Abstract:
The invention provides a low dielectric material. The low dielectric material comprises: (i) 5-50 parts by weight of polyphenylene ether (PPE) resin having a Mw of 1000˜7000, a Mn of 1000-4000 and Mw/Mn=1.0-1.8; and (ii) 10-90 parts by weight of liquid crystal polymer with allyl group having a Mw of 1000˜5000, a Mn of 1000-4000 and Mw/Mn=1.0-1.8, wherein the dielectric material has Dk of 3.4-4.0 and Df of 0.0025-0.0050. The dielectric material is suitably used in prepregs and insulation layers of a circuit board, because it has high Tg, low thermal expansion coefficient, low moisture absorption and excellent dielectric properties such as Dk and Df

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Continuation-in-Part of co-pending application Ser. No. 13/845,908, filed on Mar. 18, 2013. The entire contents of which are hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Technical Field 
         [0003]    The invention relates to a material with low dielectric loss, particularly to a resin composition. 
         [0004]    2. Related Art 
         [0005]    As developed with wireless transmission products and technologies of transmitting high frequency, epoxy resin and novolak resin cannot satisfied for the advance application, especially high frequency printed circuit board (PCB). Fluorine-containing resin can be used as PCB with low dielectric loss. However, fluorine-containing resin is expensive and not easy to work, and thus limited to the use of military and astrodynamics. In addition, polyphenylene ether (PPE) resin has excellent mechanical property and dielectric property such as Dk and Df. Therefore, the PPE resin is preferable to be used a material for high frequency PCB. 
         [0006]    However, because the PPE resin is a thermal plastic resin, as applied in a copper-clad laminate, it may has disadvantages as follows: it is not easy to work due to a high melting viscosity of PPE resin, interlayer film is easy released in a solvent clean step during a process for manufacturing PCB due to a poor solvent resistance of PPE resin, and it is not easy to operate above a temperature of 250° C. in soldering process due to melting point close to Tg. Therefore, PPE resin has to be modified by curing so as to meet the requirement of using in PCB. 
         [0007]    Curing modification of PPE resin generally has two manners: PPE resin may become curable resin by introducing crosslinking active functional groups to molecular structure of PPE resin. Alternatively, PPE resin may become co-mixing curable composite material by introducing other curable resins to molecular structure of PPE resin with co-mixing modification or interpenetrating network technology. However, PPE resin is likely incompatible with the active functional groups or curable resins, because the polar difference exists in their chemical structures. Alternatively, PPE resin may lose the excellent properties, after it conducts curing modification with the active functional groups or curable resins. 
         [0008]    Therefore, there is a need to develop a material has excellent dielectric properties and other properties such as high Tg, low coefficient of thermal expansion and low water absorption of PCB requirement. Also, the material can be applied in the manufacture of high frequency PCB. 
       SUMMARY OF THE INVENTION 
       [0009]    An object of the invention is to provide a low dielectric material, which has excellent dielectric properties, low coefficient of thermal expansion and low water absorption. 
         [0010]    To accomplish the above object, there is provided a low dielectric material, which comprises: (i) 5-50 parts by weight of polyphenylene ether (PPE) resin having a Mw of 1000˜7000, a Mn of 1000-4000 and Mw/Mn=1.0-1.8; and (ii) 10-90 parts by weight of liquid crystal polymer with allyl group having a Mw of 1000˜5000, a Mn of 1000-4000 and Mw/Mn=1.0-1.8, wherein the dielectric material has Dk of 3.4-4.0 and Df of 0.0025-0.0050. 
         [0011]    In the low dielectric material of the invention, the low dielectric material further comprises 0.01-15 parts by weight of bismaleimide resins. In the low dielectric material of the invention, the low dielectric material further comprises 0.01-10 parts by weight of polymer additives. 
         [0012]    In the low dielectric material of the invention, the polyphenylene ether resin is represented by the formula 
         [0000]    
       
                 
         
             
             
         
       
     
         [0013]    wherein Y represents at least one C, O and benzene ring or the combination. 
         [0014]    In the low dielectric material of the invention, bismaleimide resins are selected from groups consisting of 
         [0015]    Phenylmethane maleimide 
         [0000]    
       
                 
         
             
             
         
       
     
         [0016]    wherein n≧1; 
         [0017]    Bisphenol A diphenyl ether bismaleimide 
         [0000]    
       
                 
         
             
             
         
       
     
         [0018]    3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylethane bismaleimide 
         [0000]    
       
                 
         
             
             
         
       
     
         [0000]    and 
         [0019]    1,6-bismaleimide-(2,2,4-trimethyl)hexane. 
         [0000]    
       
                 
         
             
             
         
       
     
         [0020]    In the low dielectric material of the invention, the polymer additives are selected from groups consisting of 
         [0021]    Homopolymers of Butadiene 
         [0000]    
       
                 
         
             
             
         
       
     
         [0022]    wherein y=70% and x+z=30% ; 
         [0023]    Random copolymers of butadiene and styrene 
         [0000]    
       
                 
         
             
             
         
       
     
         [0024]    wherein y=30%, x+z=70% and w=≧1, and the amount of styrene=25 wt %; 
         [0025]    Maleinized Polybutadiene 
         [0000]    
       
                 
         
             
             
         
       
     
         [0026]    wherein y=28% and x+z=72%, the amount of maleic anhydride=8 wt %; 
         [0027]    Butadiene-styrene-divinylbenzene copolymer; and 
         [0028]    Styrene Maleic Anhydride copolymer 
         [0000]    
       
                 
         
             
             
         
       
     
         [0029]    wherein X=1˜8 and n≧1. 
         [0030]    In the low dielectric material of the invention, it is preferable that crosslinking agent is added to increase crosslinking density of resins. The crosslinking agents with 40-80 parts by weight may be selected from the following groups consisting of 
         [0000]    
       
                 
         
             
             
         
       
     
         [0031]    In the low dielectric material of the invention, it is preferable that catalyst is added to increase reaction of crosslinking agents and other resins. The catalysts includes at least one peroxide having 116° C.-128° C. for a half life of 10 hours with 2-8 phr based on the total weight of PPE, BMI, polymer additives and crosslinking agents. The suitable peroxides comprise dicumyl peroxide, α,α′-bis(tert-butylperoxy)diisopropyl benzene and 2,5-di(tert-butylperoxy)-2,5-dimethyl-3-hexyne. 
         [0032]    In the low dielectric material of the invention, it is preferable that filler is added to increase thermal conductivity and mechanical strength, and reduce thermal expansion. The suitable fillers may be fused silica, sphere-shaped silica, talc aluminum silicate and soft silica, e.g., siliesoft, wherein the soft silica can be used to reduce a drill bit wearing away when PCB is drilled to form holes by the drill bit. The soft silica has a particle size in a range of 0.5 μm-10 μm. 
         [0033]    In order to increase flame retardation of the low dielectric material of the invention, halogen-containing flame retardants and flame retardants without halogen may be used. The halogen-containing flame retardants may comprise decabromodiphenyl ethane. The flame retardants without halogen may comprise phosphor-containing flame retardants and phosphates. The phosphor-containing flame retardants and phosphates are produced by ALBEMARLE CO., LTD. The phosphates are like tetrakis(2,6-dimethylphenyl) 1,3-phenylene bisphosphate, HCA derivative (I), HCA derivative (II) and HCA derivative (III). The tetrakis(2,6-dimethylphenyl) 1,3-phenylene bisphosphate can be represented by the formula, 
         [0000]      (OC 6 H 3 (CH 3 ) 2 ) 2 P(O)OC 5 H 4 OP(O)(OC 6 H 3 (CH 3 ) 2 ) 2 ; 
         [0034]    HCA derivative (I) having the following paradiphenyl phosphoryl dibenzyl structure: 
         [0000]    
       
                 
         
             
             
         
       
     
         [0035]    HCA derivative (II) having the following structure: 
         [0000]    
       
                 
         
             
             
         
       
     
         [0036]    wherein with the proviso that when B is —CH 2 —, —CH(CH 3 )—, m is 1 and n is 1 to 3; with the proviso that when B is ═CHCH═, m=2 and n=0; and 
         [0037]    HCA derivative (III) having the following structure (XP7866, Albemarle): 
         [0000]    
       
                 
         
             
             
         
       
     
         [0000]    wherein A is a direct bond, C 6 -C 12  aryl, C 3 -C 12  cycloalkyl, or a C 3 -C 12  cycloalkenyl, wherein said cycloalkyl or cycloalkenyl may be optionally substituted by a C 1 -C 6  alkyl;
   each R 1 , R 2 , R 3  and R 4  are independently hydrogen, C 1 -C 15  alkyl, C 6 -C 12  aryl, C 7 -C 15  aralkyl or C 7 -C 15  alkaryl; or R 1  and R 2  or R 3  and R 4  taken together can form a saturated or unsaturated cyclic ring, wherein said saturated or unsaturated cyclic ring may be optional substituted by a C 1 -C 6  alkyl;   each m is independently 1, 2, 3 or 4   each R 5  and R 6  are independently hydrogen or a C 1 -C 6  alkyl;   each n is independently 0, 1, 2, 3, 4 or 5;   with the proviso that when A is aryl or a direct bond, n cannot be 0.   
 
         [0043]    The foregoing and other objects, features and advantages of the present invention will be apparent to those skilled in the art from the following detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0044]    The features of the invention believed to be novel are set forth with particularity in the appended claims. The invention itself, however, may be best understood by reference to the following detailed description of the invention, which describes an exemplary embodiment of the invention, taken in conjunction with the accompanying drawings, in which: 
           [0045]    The FIGURE shows a FTIR spectrum of liquid crystal polymer of an embodiment according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0046]    In one aspect of the present invention, there is provided a thermal curable dielectric material to produce a prepreg in a successive process in the following examples 4-1 to 4-7. The process uses the dielectric material as a coating on a substrate which may be a fiberglass cloth. The apparatus for producing the prepreg includes a pasting tank wherein there are provided a plurality of rolls. The pasting tank is filled with the dielectric material. A roll of fiberglass cloth may enter the pasting tank and pass the plurality of rolls. The fiberglass cloth is sufficiently impregnated with the dielectric material, and then surplus dielectric material is removed by a metering roller. A heat treatment for curing the dielectric material and removing the solvent is required at 100° C. to 350° C. for 1 minute to 5 hours, preferably at 150° C. to 300° C. for 1 minute to 3 hours. The prepreg is obtained after the cured dielectric material is cooled down and the fiberglass cloth is wrapped. 
         [0047]    A double-sided copper-clad laminate is produced by providing several prepregs in a neat stack between two electrodeposited copper foils, conducting a hot pressing process under 40 to 900 psi, raising temperature from 80° C. to 200° C. in 30 minutes, and then hot pressing at 200° C. for 120 minutes, and then cooling down to room temperature in 30 minutes in a vacuum pressing machine. The prepreg includes a fiberglass cloth of electrical grade 2116 and the dielectric material. Generally, a double-sided copper-clad laminate with a thickness of 1.0 mm is produced by providing 4 sheets of prepregs in a neat stack between two electrodeposited copper foils, with a thickness of 1.5 mm is produced by providing 7 sheets of prepregs, and with a thickness of 2.0 mm is produced by providing 10 sheets of prepregs. 
         [0048]    The low dielectric material of the present invention may form a stable homogeneous solution in a solvent with a low boiling point. The properties of a copper-clad laminate with the dielectric material of the invention were determined including Tg, heat decomposition temperature, heat decomposition time, solder heat resistance (288° C.), thermal expansion coefficient, water absorption, thermal conductivity, dielectric constant, dielectric loss tangent and flammability according to IPC-TM-650 test method manual. The determining results show the copper-clad laminate with the dielectric material of the invention has high Tg, excellent dielectric properties such as Dk and Df, low water absorption, high thermal resistance and high thermal conductivity. The copper-clad laminate is suitable used as a substrate for electronic elements and IC package. 
       EXAMPLES 
       [0049]      
         [0000]    
       
         
               
             
               
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 1-1 
               
             
             
               
                   
               
               
                 INFLUENCE OF PPE RESIN AMOUNT 
               
             
          
           
               
                   
                 AMOUNT OF PPE RESIN 
               
             
          
           
               
                 EXAMPLE 4-1-1 
                 C1 
                 C2 
                 C3 
                 C4 
                 C5 
                 C6 
                 C7 
               
               
                   
               
             
          
           
               
                 PPE resin 
                 SA9000 
                 60 
                 52.5 
                 45 
                 41 
                 37.5 
                 34 
                 22.5 
               
               
                 BMI resin 
                 5100 
                 15 
                 15 
                 15 
                 15 
                 15 
                 15 
                 15 
               
               
                 Polybutadiene 
                 Ricon100 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
               
               
                 Crosslinking 
                 TAIC 
                 15 
                 22.5 
                 30 
                 34 
                 37.5 
                 41 
                 52.5 
               
               
                 agents 
               
               
                 Flame 
                 XP7866, phr 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
               
               
                 retardants 
               
               
                 fillers 
                 Fused silica, 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
               
               
                   
                 phr 
               
               
                 catalysts 
                 Peroxide 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
               
               
                   
                 119° C. for a 
               
               
                   
                 half life of 
               
               
                   
                 10 hrs 
               
               
                 Tg, TMA 
                 IPC-TM-650 
                 206 
                 224 
                 229 
                 221 
                 212 
                 213 
                 212 
               
               
                   
                 2.4.24.3 
               
               
                 coefficient of 
                 IPC-TM-650 
                 58/334 
                 60/305 
                 56/251 
                 53/247 
                 56/211 
                 61/204 
                 55/245 
               
               
                 thermal 
                 2.4.24 
               
               
                 expansion 
               
               
                 (α1/α2), ppm/ 
               
               
                 ° C. 
               
               
                 water 
                 PCT/121° C./ 
                 0.29 
                 0.33 
                 0.34 
                 0.34 
                 0.39 
                 0.39 
                 0.40 
               
               
                 absorption 
                 1 hr 
               
               
                 288° C. 
                 Dip288° C. 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
               
               
                 thermal 
               
               
                 resistance 
               
               
                 Dk(2-10 GHz) 
                 Cavity 
                 3.93 
                 3.89 
                 3.89 
                 3.89 
                 3.90 
                 3.86 
                 3.87 
               
               
                 Df(2-10 GHz) 
                 Cavity 
                 0.0057 
                 0.0054 
                 0.0048 
                 0.0044 
                 0.0040 
                 0.0040 
                 0.0039 
               
               
                 flammability 
                 UL94 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
               
               
                   
               
             
          
         
       
     
         [0050]    Tg, Dk and Df were compared with different ratio and amount of PPE. The Tg level may be affected by the amount of PPE used. Also, the amount of PPE may also have an effect on the Dk and Df value. When the amount of PPE is high, Dk and Df may be high. When the amount of PPE is low, Dk and Df may be low. Typically, a low value for the Dk and Df is preferred. In addition, the thermal expansion coefficient may be raised when PPE is added, and BMI is added to balance the effect. In Table 1-1, part number SA9000 of PPE with chemical name of Polyphenylene Oxide (PPO) or Polyphenylene Ether (PPE) is produced by Sabic CO., LTD. 
         [0000]    
       
         
               
             
               
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 1-2 
               
             
             
               
                   
               
               
                 INFLUENCE OF LCP AMOUNT 
               
             
          
           
               
                   
                 AMOUNT OF LCP 
               
             
          
           
               
                 EXAMPLE 4-1-2 
                 C8 
                 C9 
                 C10 
                 C11 
                 C12 
                 C13 
               
               
                   
               
             
          
           
               
                 PPE resin 
                 SA9000 
                 48.5 
                 27 
                 5.4 
                 13.5 
                 13.5 
                 13.5 
               
               
                 BMI resin 
                 5100 
                 0 
                 0 
                 0 
                 15 
                 15 
                 15 
               
               
                 Polybutadiene 
                 Ricon100 
                 0 
                 0 
                 0 
                 10 
                 10 
                 10 
               
               
                 LCP 
                 — 
                 10 
                 50 
                 90 
                 50 
                 50 
                 50 
               
               
                 Crosslinking 
                 TAIC 
                 41.5 
                 23 
                 4.6 
                 11.5 
                 11.5 
                 11.5 
               
               
                 agents 
               
               
                 Flame 
                 HCA derivative (II), 
                 0 
                 0 
                 0 
                 0 
                 27 
                 27 
               
               
                 retardants 
                 phr 
               
               
                   
                 Decabromodiphenyl 
                 11 
                 14 
                 18 
                 12 
                 0 
                 0 
               
               
                   
                 Ethane, phr 
               
               
                 fillers 
                 Fused silica, phr 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
               
               
                 catalysts 
                 Peroxide 119° C. for 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
               
               
                   
                 a half life of 10 hrs 
               
               
                   
                 Imidozole, phr 
                 0.1 
                 0.5 
                 0.9 
                 0.5 
                 0.5 
                 0.5 
               
               
                 Tg, TMA, ° C. 
                 IPC-TM-650 
                 193 
                 219 
                 205 
                 225 
                 230 
                 227 
               
               
                   
                 2.4.24.3 
               
               
                 coefficient of 
                 IPC-TM-650 2.4.24 
                 49/244 
                 45/232 
                 47/250 
                 44/240 
                 56/231 
                 59/245 
               
               
                 thermal 
               
               
                 expansion 
               
               
                 (α1/α2), ppm/ 
               
               
                 ° C. 
               
               
                 water 
                 PCT/121° C./1 hr 
                 0.30 
                 0.31 
                 0.33 
                 0.32 
                 0.34 
                 0.31 
               
               
                 absorption 
               
               
                 288° C. 
                 Dip288° C. 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
               
               
                 thermal 
               
               
                 resistance 
               
               
                 Dk(2-10 GHz) 
                 Cavity 
                 3.95 
                 3.94 
                 3.96 
                 3.9 
                 3.91 
                 3.41 
               
               
                 Df(2-10 GHz) 
                 Cavity 
                 0.0041 
                 0.0045 
                 0.0046 
                 0.0042 
                 0.0041 
                 0.0026 
               
               
                 flammability 
                 UL94 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
               
               
                   
               
             
          
         
       
     
         [0051]    Liquid crystal polymers generally exhibit good chemical, moisture and temperature resistance, and good mechanical strength, and can be formed into thin films that have a high degree of structural integrity. However, the cost and/or the dielectric constant of a film made solely of LCP may be too high for certain electronic applications. 
         [0052]    The liquid crystal polymer according to the present invention is selected from a liquid crystalline polymer (or a thermoplastic polymer capable of forming an optically anisotropic melt phase) processable in a molten state. Chemical formulation of the liquid crystal polymer is not particularly limited to a specific one as long as it is a liquid crystalline polymer that can be melt-processable, and examples thereof may include a thermoplastic liquid crystal polymer of vinyl type, a thermoplastic liquid crystal aromatic polyamide, or a thermoplastic liquid crystal aromatic polyester, and preferably, modified by introducing allyl group at terminals and/or side ends thereto. The liquid crystal polymer of the present invention can carry out free radical reaction to form an interpenetrating polymer network by the allyl group. In Table 1-2, Example 13 uses low Dk glass fiber, and Example 8 and Example 9 use E-glass fiber. 
         [0053]    The thermoplastic liquid crystal polymer of vinyl type has the following structure: 
         [0000]    
       
                 
         
             
             
         
       
     
         [0054]    The thermoplastic liquid crystal aromatic polyamide has the following structure: 
         [0000]    
       
                 
         
             
             
         
       
     
         [0055]    The liquid crystal polymer of the present invention has FTIR spectrum shown as the FIGURE Peak 3472 cm −1  relates to —OH or —NH stretch. Peak 3097 cm −1  relates to Vinyl or —CH2 asymmetric stretch. Peaks 2950 cm-1, 2919-1 cm, 2874 cm-1 and 2842 cm-1 relate to —C≡C—H, —C═CH2, —C—CH3 or 
         [0000]    
       
                 
         
             
             
         
       
     
         [0000]    Peaks 1730 cm-1 and 1715 cm-1 relate to aromatic ester, C═O stretch, saturated C═O stretch or aromatic C═O. Peaks 1640 cm-1 and 1605 cm-1 relate to —C═C or ring mode C═C. Peaks 1640 cm-1, 1570 cm-1 and 1482 cm-1 relate to —NH bending or asymmetric 
         [0000]    
       
                 
         
             
             
         
       
     
         [0000]    stretch. Peaks 1459 cm-1 and 1377 cm-1 relate to 
         [0000]    
       
                 
         
             
             
         
       
     
         [0000]    symmetric stretch. Peaks 1299 cm-1, 1244 cm-1, 1188 cm-1, 1153 cm-1, 1043 cm-1 and 1023 cm-1 relate to —C—O—, —C—O—C— or —C—C—C—. Peaks 1377 cm-1 to 1023 cm-1 relate to amide, imide, —CN stretch. Peaks 827 cm-1 to 691 cm-1 relate to —C═C— on benzene ring, para or meta substituted phenyl or —NH out of plane wagging or mono. It can be found from the FIGURE that peaks identify the thermoplastic liquid crystal polymer of vinyl type and the thermoplastic liquid crystal aromatic polyamide. 
         [0000]    
       
         
               
             
               
               
             
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
             
               
               
             
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                 INFLUENCE OF BMI RESIN SPECIES AND AMOUNT 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 BMI RESIN 
               
             
          
           
               
                 EXAMPLE 4-2 
                 A1 
                 A2 
                 A3 
                 A4 
                 A5 
                 A6 
                 A7 
                 A8 
               
               
                   
               
             
          
           
               
                 PPE resin 
                 SA9000 
                 42.5 
                 40 
                 37.5 
                 35 
                 32.5 
                 37.5 
                 37.5 
                 37.5 
               
               
                 BMI resin 
                 2300 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 15 
                 0 
               
               
                   
                 4000 
                 0 
                 0 
                 0 
                 0 
                 0 
                 15 
                 0 
                 0 
               
               
                   
                 5100 
                 5 
                 10 
                 15 
                 20 
                 25 
                 0 
                 0 
                 0 
               
               
                   
                 TMH 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 15 
               
               
                 Polybutadiene 
                 Ricon100 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
               
               
                 Crosslinking 
                 TAIC 
                 42.5 
                 40 
                 37.5 
                 35 
                 32.5 
                 37.5 
                 37.5 
                 37.5 
               
               
                 agents 
               
               
                 Flame 
                 XP7866, 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
               
               
                 retardants 
                 phr 
               
               
                 fillers 
                 Fused 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
               
               
                   
                 silica, 
               
               
                   
                 phr 
               
               
                 catalysts 
                 Peroxide 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
               
               
                   
                 119° C. 
               
               
                   
                 for a half 
               
               
                   
                 life of 
               
               
                   
                 10 hrs 
               
               
                 Tg, TMA 
                 IPC-TM- 
                 210 
                 212 
                 212 
                 211 
                 211 
                 212 
                 222 
                 195 
               
               
                   
                 650 
               
               
                   
                 2.4.24.3 
               
               
                 Coefficient 
                 IPC-TM- 
                 60/296 
                 58/250 
                 56/211 
                 54/207 
                 50/197 
                 55/260 
                 45/170 
                 45/288 
               
               
                 of 
                 650 
               
               
                 thermal 
                 2.4.24 
               
               
                 expansion 
               
               
                 (α1/α2), 
               
               
                 ppm/° C. 
               
               
                 water 
                 PCT/121° C./ 
                 0.30 
                 0.34 
                 0.39 
                 0.44 
                 0.46 
                 0.41 
                 0.47 
                 0.33 
               
               
                 absorption 
                 1 hr 
               
               
                 288° C. 
                 Dip288° C. 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
               
               
                 thermal 
               
               
                 resistance 
               
               
                 Dk(2-10 GHz) 
                 Cavity 
                 3.85 
                 3.87 
                 3.90 
                 3.94 
                 3.98 
                 3.91 
                 3.93 
                 3.86 
               
               
                 Df(2-10 GHz) 
                 Cavity 
                 0.0040 
                 0.0041 
                 0.0040 
                 0.0042 
                 0.0043 
                 0.0042 
                 0.0046 
                 0.0041 
               
               
                 flammability 
                 UL94 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-1 
                 V-0 
                 V-0 
               
               
                   
               
             
          
           
               
                   
                 BMI RESIN 
               
             
          
           
               
                   
                   
                   
                   
                   
                   
                   
                   
                 Comparative 
               
               
                 EXAMPLE 4-2 
                 A9 
                 A10 
                 A11 
                 A12 
                 A13 
                 A14 
                 A15 
                 example 
               
               
                   
               
             
          
           
               
                 PPE resin 
                 SA9000 
                 37 
                 37 
                 37 
                 37 
                 37 
                 37.5 
                 37 
                 50 
               
               
                 BMI resin 
                 2300 
                 8 
                 0 
                 8 
                 0 
                 0 
                 5 
                 4 
                 0 
               
               
                   
                 4000 
                 8 
                 8 
                 0 
                 8 
                 0 
                 5 
                 4 
                 0 
               
               
                   
                 5100 
                 0 
                 8 
                 0 
                 0 
                 8 
                 5 
                 4 
                 0 
               
               
                   
                 TMH 
                 0 
                 0 
                 8 
                 8 
                 8 
                 0 
                 4 
                 0 
               
               
                 Polybutadiene 
                 Ricon 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
                 0 
               
               
                   
                 100 
               
               
                 Crosslinking 
                 TAIC 
                 37 
                 37 
                 37 
                 37 
                 37 
                 37.5 
                 37 
                 50 
               
               
                 agents 
               
               
                 Flame 
                 XP7866, 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
               
               
                 retardants 
                 phr 
               
               
                 fillers 
                 Fused 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
               
               
                   
                 silica, 
               
               
                   
                 phr 
               
               
                 catalysts 
                 Peroxide 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
               
               
                   
                 119° C. 
               
               
                   
                 for a 
               
               
                   
                 half 
               
               
                   
                 life of 
               
               
                   
                 10 hrs 
               
               
                 Tg, TMA 
                 IPC-TM- 
                 208 
                 204 
                 205 
                 200 
                 214 
                 210 
                 207 
                 218 
               
               
                   
                 650 
               
               
                   
                 2.4.24.3 
               
               
                 Coefficient 
                 IPC-TM- 
                 50/210 
                 57/278 
                 45/230 
                 52/268 
                 54/290 
                 53/240 
                 49/225 
                 64/325 
               
               
                 of 
                 650 
               
               
                 thermal 
                 2.4.24 
               
               
                 expansion 
               
               
                 (α1/α2), 
               
               
                 ppm/° C. 
               
               
                 water 
                 PCT/121° C./ 
                 0.43 
                 0.42 
                 0.41 
                 0.36 
                 0.44 
                 0.40 
                 0.39 
                 0.33 
               
               
                 absorption 
                 1 hr 
               
               
                 288° C. 
                 Dip288° C. 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
               
               
                 thermal 
               
               
                 resistance 
               
               
                 Dk(2-10 GHz) 
                 Cavity 
                 3.96 
                 3.91 
                 3.90 
                 3.87 
                 3.89 
                 3.91 
                 3.90 
                 3.80 
               
               
                 Df(2-10 GHz) 
                 Cavity 
                 0.0041 
                 0.0041 
                 0.0045 
                 0.004 
                 0.0039 
                 0.0041 
                 0.0043 
                 0.0044 
               
               
                 flammability 
                 UL94 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
               
               
                   
               
             
          
         
       
     
         [0056]    The coefficient of thermal expansion was measured with different species and amount of BMI resin. The more the amount of BMI resin is, the lower the coefficient of thermal expansion is. In the example, there are three kinds of comparison comprising three groups that A1-A5 shows different amount of BMI with the same species, A6-A8 shows the same amount of BMI with different species and A9-A15 shows about the same total amount of BMI with more than two species. In Table 2, part numbers 2300, 4000, 5100 and TMH of BMI are produced by Daiwakasei Industry CO., LTD, in which part number 2300 has chemical name of phenyl methane maleimide, part number 4000 has chemical name of 2,2′-bis[4-(4-maleimidophenoxy)phenyl]propane, part number 5100 has chemical name of 3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethane bismaleimide and part number TMH has chemical name of 1,6′-bismaleimide-(2,2,4-trimethyl)hexane. 
         [0057]    It can be found from group A1-A5 that by increasing the amount of BMI resin, the thermal expansion coefficient would decrease. However, by increasing the amount of BMI resin, the water absorption would also increase. As to group A6-A8, different BMI resins may reduce the thermal expansion coefficient, but would also affect the water absorption. Regarding group A9-A15, different combination of BMI resins may reduce the thermal expansion coefficient, and affect the water absorption also. In the invention, the object of addition of BMI to the dielectric material is to reduce the thermal expansion coefficient. However, the more the amount of BMI resin is, the higher the water absorption is. Therefore, the polymer additives are added to reduce the water absorption. 
         [0000]    
       
         
               
             
               
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
             
               
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 3 
               
               
                   
               
               
                 INFLUENCE OF POLYMER ADDITIVES SPECIES AND AMOUNT 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 POLYMER ADDITIVES 
               
             
          
           
               
                 EXAMPLE 4-3 
                 B1 
                 B2 
                 B3 
                 B4 
                 B5 
                 B6 
                 B7 
               
               
                   
               
             
          
           
               
                 PPE resin 
                 SA9000 
                 40 
                 37.5 
                 35 
                 32.5 
                 30 
                 37.5 
                 37.5 
               
               
                 BMI resin 
                 5100 
                 15 
                 15 
                 15 
                 15 
                 15 
                 15 
                 15 
               
               
                 Polybutadiene 
                 Ricon100 
                 5 
                 10 
                 15 
                 20 
                 25 
                 0 
                 0 
               
               
                   
                 Ricon130MA8 
                 0 
                 0 
                 0 
                 0 
                 0 
                 10 
                 0 
               
               
                   
                 Ricon150 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 10 
               
               
                   
                 Ricon257 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
               
               
                 SMA 
                 S:M = 3:1 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
               
               
                   
                 S:M = 4:1 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
               
               
                   
                 S:M = 5:1 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
               
               
                   
                 S:M = 6:1 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
               
               
                   
                 S:M = 8:1 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
               
               
                 Crosslinking 
                 TAIC 
                 40 
                 37.5 
                 35 
                 32.5 
                 30 
                 37.5 
                 37.5 
               
               
                 agents 
               
               
                 Flame retardant 
                 XP7866, phr 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
               
               
                 Fillers 
                 Fused silica, phr 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
               
               
                 catalysts 
                 Peroxide 119° C. 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
               
               
                   
                 for a half life of 
               
               
                   
                 10 hrs 
               
               
                 Tg, TMA 
                 IPC-TM-650 
                 221 
                 212 
                 200 
                 194 
                 186 
                 213 
                 217 
               
               
                   
                 2.4.24.3 
               
               
                 coefficient of 
                 IPC-TM-650 
                 53/201 
                 56/211 
                 64/220 
                 67/260 
                 74/300 
                 58/265 
                 57/270 
               
               
                 thermal expansion 
                 2.4.24 
               
               
                 (α1/α2), ppm/° C. 
               
               
                 water absorption 
                 PCT/121° C./1 hr 
                 0.43 
                 0.39 
                 0.35 
                 0.32 
                 0.28 
                 0.45 
                 0.43 
               
               
                 288° C. thermal 
                 Dip288° C. 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
               
               
                 resistance 
               
               
                 Dk(2-10 GHz) 
                 Cavity 
                 3.93 
                 3.90 
                 3.87 
                 3.86 
                 3.84 
                 3.92 
                 3.90 
               
               
                 Df(2-10 GHz) 
                 Cavity 
                 0.0043 
                 0.0040 
                 0.0041 
                 0.0040 
                 0.0039 
                 0.0045 
                 0.0044 
               
               
                 flammability 
                 UL94 
                 V-0 
                 V-0 
                 V-0 
                 V-1 
                 V-1 
                 V-0 
                 V-0 
               
               
                   
               
             
          
           
               
                   
                 POLYMER ADDITIVES 
               
             
          
           
               
                   
                   
                   
                   
                   
                   
                 Comparative 
               
               
                 EXAMPLE 4-3 
                 B9 
                 B10 
                 B11 
                 B12 
                 B13 
                 example 
               
               
                   
               
             
          
           
               
                 PPE resin 
                 SA9000 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
                 42.5 
               
               
                 BMI resin 
                 5100 
                 15 
                 15 
                 15 
                 15 
                 15 
                 15 
               
               
                 Polybutadiene 
                 Ricon100 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
               
               
                   
                 Ricon130MA8 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
               
               
                   
                 Ricon150 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
               
               
                   
                 Ricon257 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
               
               
                 SMA 
                 S:M = 3:1 
                 10 
                 0 
                 0 
                 0 
                 0 
                 0 
               
               
                   
                 S:M = 4:1 
                 0 
                 10 
                 0 
                 0 
                 0 
                 0 
               
               
                   
                 S:M = 5:1 
                 0 
                 0 
                 10 
                 0 
                 0 
                 0 
               
               
                   
                 S:M = 6:1 
                 0 
                 0 
                 0 
                 10 
                 0 
                 0 
               
               
                   
                 S:M = 8:1 
                 0 
                 0 
                 0 
                 0 
                 10 
                 0 
               
               
                 Crosslinking agents 
                 TAIC 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
                 42.5 
               
               
                 Flame retardants 
                 XP7866, phr 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
               
               
                 fillers 
                 Fused silica, phr 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
               
               
                 catalysts 
                 Peroxide 119° C. 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
               
               
                   
                 for a half life of 
               
               
                   
                 10 hrs 
               
               
                 Tg, TMA 
                 IPC-TM-650 
                 220 
                 215 
                 210 
                 206 
                 195 
                 222 
               
               
                   
                 2.4.24.3 
               
               
                 coefficient of 
                 IPC-TM-650 
                 45/232 
                 48/237 
                 50/245 
                 51/240 
                 53/260 
                 45/200 
               
               
                 thermal expansion 
                 2.4.24 
               
               
                 (α1/α2), ppm/° C. 
               
               
                 water absorption 
                 PCT/121° C./1 hr 
                 0.46 
                 0.45 
                 0.43 
                 0.43 
                 0.40 
                 0.56 
               
               
                 288° C. thermal 
                 Dip288° C. 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
               
               
                 resistance 
               
               
                 Dk(2-10 GHz) 
                 Cavity 
                 3.95 
                 3.95 
                 3.93 
                 3.91 
                 3.90 
                 3.93 
               
               
                 Df(2-10 GHz) 
                 Cavity 
                 0.0085 
                 0.0073 
                 0.0064 
                 0.0056 
                 0.0042 
                 0.0043 
               
               
                 flammability 
                 UL94 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
               
               
                   
               
             
          
         
       
     
         [0058]    The water absorption was measured with different species and amount of polymer additives. Polybutadiene (PB) and styrene-maleic anhydride (SMA) were used as the polymer additives in the invention. It can be found from using the different amount of PB with the same species that by increasing the amount of PB, the water absorption would decrease. However, with the increasing amount of PB, the coefficient of thermal expansion would also increase. As to using different species of PB in combination with SMA, it shows SMA can reduce the water absorption and the coefficient of thermal expansion, but Df may remain high. However, PB can be used to reduce Df In Table 3, part numbers Ricon100, Ricon130MA8, Ricon150 and Ricon257 of PB are produced by Sartomer CO., LTD, in which part number Ricon100 has chemical name of butadiene styrene copolymer, part number Ricon130MA8 has chemical name of butadiene adducted with maleic anhydride, part number Ricon 150 has chemical name of polybutadiene resin and Ricon 257 has chemical name of polybutadiene grafted with styrene and benzene in toluene solution. In Table 3, SMA with S:M=3:1 indicates that the ratio of styrene to maleic anhydride is 3 to 1. Generally, the ratios are about 1:1˜12:1. 
         [0000]    
       
         
               
             
               
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 4 
               
             
             
               
                   
               
               
                 INFLUENCE OF DIFFERENT SPECIES OF CROSSLINKING AGENTS 
               
             
          
           
               
                   
                 CROSSLINKING AGENT 
               
             
          
           
               
                 EXAMPLE 4-4 
                 D1 
                 D2 
                 D3 
                 D4 
                 D5 
               
               
                   
               
             
          
           
               
                 PPE resin 
                 SA9000 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
               
               
                 BMI resin 
                 5100 
                 15 
                 15 
                 15 
                 15 
                 15 
               
               
                 polybutadiene 
                 Ricon100 
                 10 
                 10 
                 10 
                 10 
                 10 
               
               
                 Crosslinking 
                 TAC 
                 37.5 
                 0 
                 0 
                 0 
                 0 
               
               
                 agents 
                 TAIC 
                 0 
                 37.5 
                 0 
                 0 
                 0 
               
               
                   
                 TBS 
                 0 
                 0 
                 37.5 
                 0 
                 0 
               
               
                   
                 TMAIC 
                 0 
                 0 
                 0 
                 37.5 
                 37.5 
               
               
                 Flame retardants 
                 XP7866, phr 
                 20 
                 20 
                 20 
                 0 
                 0 
               
               
                   
                 Decabromodiphenyl 
                 0 
                 0 
                 0 
                 10 
                 0 
               
               
                   
                 Ethane, phr 
               
               
                   
                 HCA derivative (II), 
                 0 
                 0 
                 0 
                 0 
                 20 
               
               
                   
                 phr 
               
               
                 fillers 
                 Fused silica, phr 
                 20 
                 20 
                 20 
                 20 
                 20 
               
               
                 catalysts 
                 Peroxide 119° C. for 
                 2.5 
                 2.5 
                 2.5 
                 4 
                 4 
               
               
                   
                 a half life of 10 hrs 
               
               
                 Tg, TMA 
                 IPC-TM-650 
                 183 
                 212 
                 202 
                 188 
                 183 
               
               
                   
                 2.4.24.3 
               
               
                 coefficient of 
                 IPC-TM-650 2.4.24 
                 59/273 
                 56/211 
                 50/250 
                 49/267 
                 50/235 
               
               
                 thermal 
               
               
                 expansion 
               
               
                 (α1/α2), ppm/° C. 
               
               
                 water absorption 
                 PCT/121° C./1 hr 
                 0.39 
                 0.39 
                 0.12 
                 0.35 
                 0.30 
               
               
                 288° C. thermal 
                 Dip288° C. 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
               
               
                 resistance 
               
               
                 Dk(2-10 GHz) 
                 Cavity 
                 3.95 
                 3.90 
                 3.75 
                 3.86 
                 3.91 
               
               
                 Df(2-10 GHz) 
                 Cavity 
                 0.0039 
                 0.0040 
                 0.0035 
                 0.004 
                 0.0038 
               
               
                 flammability 
                 UL94 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
               
               
                   
               
             
          
         
       
     
         [0059]    The dielectric material of the invention may comprise at least one crosslinking agent with 40-80 parts by weight selected from the following groups consisting of Triallyl cyanurate (TAC), Triallyl isocyanurate (TAIC), 4-tert-butylstyrene and TMAIC. The properties of a copper-clad laminate with the dielectric material of the invention were measured with different species of crosslinking agents. It can be found by using TAC that Tg and the coefficient of thermal expansion were poor, and water absorption, Dk and Df were of ordinary level. As to TAIC, all the properties of a copper-clad laminate with the dielectric material of the invention were of ordinary level. However, one drawback with TAIC is that it is volatile during hot press cycle. The use of TMAIC can effectively improve the high volatility of TAIC because TMAIC has a high melting point and does not evaporated easily, while maintaining the properties to its ordinary level. Regarding 4-tert-butylstyrene, the coefficient of thermal expansion, water absorption and Df were excellent, but Dk is low. 
         [0000]    
       
         
               
             
               
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 5 
               
             
             
               
                   
               
               
                 INFLUENCE OF DIFFERENT SPECIES OF FLAME RETARDANTS 
               
             
          
           
               
                   
                 FLAME RETARDANTS 
               
             
          
           
               
                 EXAMPLE 4-5 
                 E1 
                 E2 
                 E3 
                 E4 
                 E5 
                 E6 
               
               
                   
               
             
          
           
               
                 PPE resin 
                 SA9000 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
               
               
                 BMI resin 
                 5100 
                 15 
                 15 
                 15 
                 15 
                 15 
                 15 
               
               
                 polybutadiene 
                 Ricon100 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
               
               
                 Crosslinking 
                 TAIC 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
               
               
                 agents 
               
               
                 Flame 
                 Decabromodiphenyl 
                 10 
                 0 
                 0 
                 0 
                 0 
                 0 
               
               
                 retardants 
                 Ethane, phr 
               
               
                   
                 XP7866, phr 
                 0 
                 20 
                 15 
                 10 
                 0 
                 0 
               
               
                   
                 Tetrakis(2,6-dimethylphenyl) 
                 0 
                 0 
                 5 
                 10 
                 0 
                 0 
               
               
                   
                 1,3-phenylene 
               
               
                   
                 bisphosphate, phr 
               
               
                   
                 HCA derivative (II), phr 
                 0 
                 0 
                 0 
                 0 
                 20 
                 0 
               
               
                   
                 DPO, phr 
                 0 
                 0 
                 0 
                 0 
                 0 
                 20 
               
               
                 fillers 
                 Fused silica, phr 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
               
               
                 catalysts 
                 Peroxide 119° C. for a half 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
               
               
                   
                 life of 10 hrs 
               
               
                 Tg, TMA 
                 IPC-TM-650 2.4.24.3 
                 224 
                 212 
                 226 
                 180 
                 214 
                 224 
               
               
                 coefficient of 
                 IPC-TM-650 2.4.24 
                 55/233 
                 56/211 
                 65/267 
                 67/339 
                 50/210 
                 45/170 
               
               
                 thermal 
               
               
                 expansion 
               
               
                 (α1/α2), ppm/ 
               
               
                 ° C. 
               
               
                 water 
                 PCT/121° C./1 hr 
                 0.43 
                 0.39 
                 0.37 
                 0.30 
                 0.36 
                 0.25 
               
               
                 absorption 
               
               
                 288° C. thermal 
                 Dip288° C. 
                 &gt;60 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
               
               
                 resistance 
               
               
                 Dk(2-10 GHz) 
                 Cavity 
                 3.83 
                 3.90 
                 3.87 
                 3.85 
                 3.89 
                 3.88 
               
               
                 Df(2-10 GHz) 
                 Cavity 
                 0.0043 
                 0.0040 
                 0.0040 
                 0.0037 
                 0.0036 
                 0.0038 
               
               
                 flammability 
                 UL94 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
               
               
                   
               
             
          
         
       
     
         [0060]    If desired, the dielectric material of the invention may optionally comprise flame retardants. A halogen-containing flame retardant of decabromodiphenyl ethane with 7-15 phr based on the total weight of PPE, BMI, polymer additives and crosslinking agents may be added to the dielectric material of the invention. The dielectric material of the invention may comprise at least one flame retardant without halogen with 12-14 phr based on the total weight of PPE, BMI, polymer additives and crosslinking agents selected from the following groups consisting of phosphor-containing flame retardants and phosphates. The phosphor-containing flame retardants and phosphates are produced by ALBEMARLE CO., LTD, wherein HCA derivative (III) having product name of XP7866 comprises organic fillers, 10-15% phosphor. XP7866 has a particle size in a range of 0.5 μm-60 μm. The phosphates are like tetrakis(2,6-dimethylphenyl) 1,3-phenylene bisphosphate. 
         [0000]    
       
         
               
             
               
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
             
               
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 6 
               
               
                   
               
               
                 INFLUENCE OF DIFFERENT SPECIES OF FILLERS 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 FILLERS 
               
             
          
           
               
                 EXAMPLES 4-6 
                 F1 
                 F2 
                 F3 
                 F4 
                 F5 
                 F6 
                 F7 
               
               
                   
               
             
          
           
               
                 PPE resin 
                 SA9000 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
               
               
                 BMI resin 
                 5100 
                 15 
                 15 
                 15 
                 15 
                 15 
                 15 
                 15 
               
               
                 polybutadiene 
                 Ricon100 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
               
               
                 Crosslinking 
                 TAIC 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
               
               
                 agents 
               
               
                 Flame 
                 XP7866, phr 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
               
               
                 retardants 
               
               
                 fillers 
                 Fused silica, 
                 0 
                 20 
                 10 
                 10 
                 30 
                 25 
                 45 
               
               
                   
                 phr 
               
               
                   
                 Siliesoft, phr 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
                 0 
               
               
                   
                 Ball type 
                 20 
                 0 
                 10 
                 0 
                 0 
                 0 
                 0 
               
               
                   
                 silica 
               
               
                 catalysts 
                 Peroxide 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
                 2.5 
               
               
                   
                 119° C. for a 
               
               
                   
                 half life of 
               
               
                   
                 10 hrs 
               
               
                 Tg, TMA 
                 IPC-TM-650 
                 210 
                 212 
                 214 
                 220 
                 208 
                 215 
                 195 
               
               
                   
                 2.4.24.3 
               
               
                 coefficient of 
                 IPC-TM-650 
                 53/220 
                 56/211 
                 52/225 
                 58/260 
                 45/210 
                 50/220 
                 40/205 
               
               
                 thermal 
                 2.4.24 
               
               
                 expansion 
               
               
                 (α1/α2), ppm/ 
               
               
                 ° C. 
               
               
                 water 
                 PCT/121° C./ 
                 0.41 
                 0.39 
                 0.40 
                 0.39 
                 0.38 
                 0.40 
                 0.36 
               
               
                 absorption 
                 1 hr 
               
               
                 288° C. thermal 
                 Dip288° C. 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
               
               
                 resistance 
               
               
                 Dk(2-10 GHz) 
                 Cavity 
                 3.87 
                 3.90 
                 3.88 
                 3.85 
                 3.96 
                 4.01 
                 4.06 
               
               
                 Df(2-10 GHz) 
                 Cavity 
                 0.0039 
                 0.0040 
                 0.0040 
                 0.0040 
                 0.0041 
                 0.0043 
                 0.0045 
               
               
                 flammability 
                 UL94 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
               
               
                 Frequency of 
                 Drill holes 
                 500 
                 300 
                 400 
                 — 
                 — 
                 — 
                 — 
               
               
                 changing drill 
                 count 
               
               
                 bit 
               
               
                   
               
             
          
           
               
                   
                 FILLERS 
                   
               
             
          
           
               
                   
                 EXAMPLES 4-6 
                   
                 F8 
                 F9 
               
               
                   
                   
               
             
          
           
               
                   
                 PPE resin 
                 SA9000 
                 37.5 
                 37.5 
               
               
                   
                 BMI resin 
                 5100 
                 15 
                 15 
               
               
                   
                 polybutadiene 
                 Ricon100 
                 10 
                 10 
               
               
                   
                 Crosslinking agents 
                 TAIC 
                 37.5 
                 37.5 
               
               
                   
                 Flame retardants 
                 XP7866, phr 
                 20 
                 20 
               
               
                   
                 Fillers 
                 Fused silica, phr 
                 0 
                 0 
               
               
                   
                   
                 Siliesoft, phr 
                 10 
                 20 
               
               
                   
                   
                 Ball type silica, phr 
                 10 
                 0 
               
               
                   
                 catalysts 
                 Peroxide 119° C. for a half life 
                 2.5 
                 2.5 
               
               
                   
                   
                 of 10 hrs 
               
               
                   
                 Tg, TMA 
                 IPC-TM-650 2.4.24.3 
                 206 
                 210 
               
               
                   
                 coefficient of thermal expansion 
                 IPC-TM-650 2.4.24 
                 50/217 
                 51/222 
               
               
                   
                 (α1/α2), ppm/° C. 
               
               
                   
                 water absorption 
                 PCT/121° C./1 hr 
                 0.36 
                 0.40 
               
               
                   
                 288° C. thermal resistance 
                 Dip288° C. 
                 &gt;600 
                 &gt;600 
               
               
                   
                 Dk(2-10 GHz) 
                 Cavity 
                 3.90 
                 3.95 
               
               
                   
                 Df(2-10 GHz) 
                 Cavity 
                 0.0053 
                 0.0060 
               
               
                   
                 flammability 
                 UL94 
                 V-0 
                 V-0 
               
               
                   
                 Frequency of changing drill bit 
                 Drill holes count 
                 600 
                 800 
               
               
                   
                   
               
             
          
         
       
     
         [0061]    The low dielectric material of the invention may optionally comprise fillers. The suitable fillers such as fused silica, sphere-shaped silica and soft silica, e.g., siliesoft may be used, wherein the soft silica can be used to reduce a drill bit wearing away when PCB is drilled to form holes by the drill bit, comparing Examples F1-F3 with Examples F8-F9. The soft silica has a particle size in a range of 0.5 μm-10 μm. The suitable amount of filler is 8-50 phr based on the total weight of PPE, BMI, polymer additives and crosslinking agents. It can be found from the fused silica and the sphere-shaped silica with the same amount that the sphere-shaped silica has lower Dk and Df than the fused silica. 
         [0000]    
       
         
               
             
               
               
             
               
               
               
               
               
             
               
               
               
               
               
               
             
               
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 7 
               
               
                   
               
               
                 INFLUENCE OF DIFFERENT AMOUNT AND SPECIES OF CATALYSTS 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 CATALYSTS 
               
             
          
           
               
                 EXAMPLE 4-7 
                 G1 
                 G2 
                 G3 
                 G4 
               
               
                   
               
             
          
           
               
                 PPE resin 
                 SA9000 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
               
               
                 BMI resin 
                 5100 
                 15 
                 15 
                 15 
                 15 
               
               
                 polybutadiene 
                 Ricon100 
                 10 
                 10 
                 10 
                 10 
               
               
                 Crosslinking 
                 TAIC 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
               
               
                 agents 
               
               
                 Flame 
                 XP7866, phr 
                 20 
                 20 
                 20 
                 20 
               
               
                 retardants 
               
               
                 fillers 
                 Ball type silica 
                 20 
                 20 
                 20 
                 20 
               
               
                 catalysts 
                 Peroxide 116° C. for a 
                 0 
                 0 
                 0 
                 0 
               
               
                   
                 half life of 10 hrs 
               
               
                   
                 Peroxide 119° C. for a 
                 2.5 
                 3 
                 7 
                 8 
               
               
                   
                 half life of 10 hrs 
               
               
                   
                 Peroxide 128° C. for a 
                 0 
                 0 
                 0 
                 0 
               
               
                   
                 half life of 10 hrs 
               
               
                 Tg, TMA 
                 IPC-TM-650 2.4.24.3 
                 212 
                 220 
                 222 
                 227 
               
               
                 coefficient of 
                 IPC-TM-650 2.4.24 
                 56/211 
                 53/225 
                 49/220 
                 50/180 
               
               
                 thermal 
               
               
                 expansion 
               
               
                 (α1/α2), ppm/ 
               
               
                 ° C. 
               
               
                 water 
                 PCT/121° C./1 hr 
                 0.39 
                 0.43 
                 0.47 
                 0.60 
               
               
                 absorption 
               
               
                 288° C. thermal 
                 Dip288° C. 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
               
               
                 resistance 
               
               
                 Dk(2-10 GHz) 
                 Cavity 
                 3.90 
                 3.91 
                 3.90 
                 3.96 
               
               
                 Df(2-10 GHz) 
                 Cavity 
                 0.0040 
                 0.0042 
                 0.0045 
                 0.0049 
               
               
                 flammability 
                 UL94 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
               
               
                   
               
             
          
           
               
                   
                 CATALYSTS 
               
             
          
           
               
                 EXAMPLE 4-7 
                 G5 
                 G6 
                 G7 
                 G8 
                 G9 
               
               
                   
               
             
          
           
               
                 PPE resin 
                 SA9000 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
               
               
                 BMI resin 
                 5100 
                 15 
                 15 
                 15 
                 15 
                 15 
               
               
                 polybutadiene 
                 Ricon100 
                 10 
                 10 
                 10 
                 10 
                 10 
               
               
                 Crosslinking 
                 TAIC 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
                 37.5 
               
               
                 agents 
               
               
                 Flame 
                 XP7866, phr 
                 20 
                 13 
                 13 
                 13 
                 13 
               
               
                 retardants 
               
               
                 fillers 
                 Ball type silica 
                 20 
                 13 
                 13 
                 13 
                 13 
               
               
                 catalysts 
                 Peroxide 116° C. for a 
                 2.5 
                 0 
                 1.5 
                 1.5 
                 1 
               
               
                   
                 half life of 10 hrs 
               
               
                   
                 Peroxide 119° C. for a 
                 0 
                 0 
                 0 
                 1.5 
                 1 
               
               
                   
                 half life of 10 hrs 
               
               
                   
                 Peroxide 128° C. for a 
                 0 
                 2.5 
                 1.5 
                 0 
                 1 
               
               
                   
                 half life of 10 hrs 
               
               
                 Tg, TMA 
                 IPC-TM-650 2.4.24.3 
                 208 
                 225 
                 220 
                 209 
                 215 
               
               
                 coefficient of 
                 IPC-TM-650 2.4.24 
                 57/230 
                 50/230 
                 47/226 
                 52/220 
                 50/235 
               
               
                 thermal 
               
               
                 expansion 
               
               
                 (α1/α2), ppm/ 
               
               
                 ° C. 
               
               
                 water 
                 PCT/121° C./1 hr 
                 0.42 
                 0.38 
                 0.40 
                 0.42 
                 0.38 
               
               
                 absorption 
               
               
                 288° C. thermal 
                 Dip288° C. 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
                 &gt;600 
               
               
                 resistance 
               
               
                 Dk(2-10 GHz) 
                 Cavity 
                 3.88 
                 3.91 
                 3.92 
                 3.93 
                 3.91 
               
               
                 Df(2-10 GHz) 
                 Cavity 
                 0.0039 
                 0.0040 
                 0.0041 
                 0.0042 
                 0.0039 
               
               
                 flammability 
                 UL94 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
                 V-0 
               
               
                   
               
             
          
         
       
     
         [0062]    The low dielectric material of the invention may optionally comprise catalysts including peroxides having 116° C.-128° C. for a half life of 10 hours. The suitable amount of peroxide is 2-8 phr based on the total weight of PPE, BMI, polymer additives and crosslinking agents. The preferable catalyst is a peroxide having 119° C. for a half life of 10 hours. 
         [0063]    The low dielectric material of the invention may comprise PPE, but not comprise epoxy resin. The desired values of Dk and/or Df cannot be obtained, if epoxy resin is added to the dielectric material of the invention. When reacting epoxy resin with the dielectric material of the invention, the open rings of the epoxy resin may produce excess OH groups, therefore causing the Dk and Df value to remain high and unable to decrease.