Source: http://www.google.com/patents/US5407872?dq=6263352
Timestamp: 2017-10-19 03:45:09
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Patent US5407872 - Glass fiber forming composition, glass fibers obtained from the composition ... - Google Patents
A glass fiber forming composition exhibits a remarkably high dielectric constant ε.sub.Γ as well as superior chemical resistance, yet it is readily spun into glass fibers. The composition is characterized to show a devitrification temperature which is lower than a spinning temperature at which the...http://www.google.com/patents/US5407872?utm_source=gb-gplus-sharePatent US5407872 - Glass fiber forming composition, glass fibers obtained from the composition and substrate for circuit board including the glass fibers as reinforcing material
Publication number US5407872 A
Application number US 08/148,539
Also published as CA2060709A1, CA2060709C, DE69210270D1, DE69210270T2, EP0498425A1, EP0498425B1, US5284807, US5334645
Publication number 08148539, 148539, US 5407872 A, US 5407872A, US-A-5407872, US5407872 A, US5407872A
Original Assignee Matsushita Electric Works Ltd., Nippon Electric Glass Co. Ltd.
Patent Citations (12), Non-Patent Citations (4), Referenced by (35), Classifications (22), Legal Events (5)
Glass fiber forming composition, glass fibers obtained from the composition and substrate for circuit board including the glass fibers as reinforcing material
US 5407872 A
A glass fiber forming composition exhibits a remarkably high dielectric constant ε.sub.Γ as well as superior chemical resistance, yet it is readily spun into glass fibers. The composition is characterized to show a devitrification temperature which is lower than a spinning temperature at which the glass composition exhibits a viscosity of 102.5 poise, so as to be readily spun into corresponding glass fibers. The composition consists essentially of 40 to 65 mol % of SiO2 ; 20 to 45 mol % of at least one component selected from the group consisting of MgO, CaO, SrO and BaO; 5 to 25 mol % of at least one component selected from the group consisting of TiO2 and ZrO2 ; and 0.5 to 15 mol % of NbO5/2 as calculated from an incorporated amount of Nb2 O5. Alternately, the composition consist essentially of 40 to 65 mol % of SiO2 ; 20 to 45 mol % of at least one component selected from the group consisting of CaO, SrO and BaO; 5 to 25 mol % of at least one component selected from the group consisting of TiO2 and ZrO2 ; 0.5 to 15 mol % of NbO5/2 as calculated from an incorporated amount of Nb2 O5 ; and 0.5 to 15 mol % of AlO3/2 as calculated from an incorporated amount of Al2 O3. The composition is also characterized to incorporate at least 85 mol % of a total amount of the oxides and have a dielectric constant [ε.sub.Γ ] of 9 or more at 1 MHz and 25° C.
1. A glass fiber forming composition consisting essentially of 0 to 15 mol % of at least one oxide selected from the group consisting of TaO2.5, LaO1.5, CeO2, ZnO, Li2 O, Na2 O, K2 O, MnO2, and BO1.5, and 85-100 mol % of an oxide mixture, said oxide mixture consisting essentially of:
CaO, SrO and BaO each being present, said CaO, SrO and BaO being present in respective amounts which total 20 to 45 mol % of the oxide mixture;
0. 5 to 15 mol % of NbO5/2 ;
said composition having a dielectric constant ε.sub.Γ of 9 or more at 1 MHz and 25° C.; and said composition being characterized to show a devitrification temperature which is lower than a spinning temperature at which said composition exhibits a viscosity of 102.5 poise.
2. A glass fiber forming composition as set forth in claim 1, wherein said oxide mixture consists essentially of:
1to 10 mol % of NbO5/2.
3. A glass fiber forming composition consisting essentially of 0 to 15 mol % of at least one oxide selected from the group consisting of TaO2.5, LaO1.5, CeO2, ZnO, Li2 O, Na2 O, K2 O, MnO2, and BO1.5, and 85-100 mol % of an oxide mixture, said oxide mixture consisting essentially of:
40 to 65 mol % of SiO2 ; CaO, SrO and BaO each being present, said CaO, SrO and BaO being present in respective amounts which total 20 to 45 mol % of the oxide mixture;
said composition having a dielectric constant ε.sub.Γ of 9 or more at 1 MHz and 25° C.; ; and
4. A glass fiber forming composition as set forth in claim 3, said composition consisting essentially of 0 to 15 mol % of at least one oxide selected from the group consisting of TaO2.5, LaO1.5, CeO2, ZnO, Li2 O, Na2 O, K2 O, MnO2, and BO1.5, and 85-100 mol % of an oxide mixture, said oxide mixture consisting essentially of:
46 to 60 mol % of SiO2 ; CaO, SrO and BaO, in amounts which total 26.2 to 31.5 mol % of the oxide mixture, with 6.8 to 9.0 mol % of CaO, 6.0 to 7.5 mol % of SrO, and 13.4 to 15.0 mol % of BaO;
TiO2 and ZrO2, in amounts which total 9.5 to 14 mol % of the oxide mixture, with 7.8 to 11.5 mol % of TiO2 and 1.7 to 2.5 mol % of ZrO2 ;
5. A glass fiber forming composition consisting essentially of 0 to 15 mol % of at least one oxide selected from the group consisting of TaO2.5, LaO1.5, CeO2, ZnO, Li2 O, Na2 O, K2 O, MnO2, and BO1.5, and 85-100 mol % of an oxide mixture, said oxide mixture consisting essentially of:
MgO, CaO, SrO and BaO each being present, said MgO, CaO, SrO and BaO being present in respective amounts which total 20 to 45 mol % of the oxide mixture;
TiO and ZrO2 in amounts which total 5 to 25 mol % of the oxide mixture;
said composition having a dielectric constant ε.sub.Γ of 9 or more at 1 MHz and 25° C.; and
6. A glass fiber forming composition as set forth in claim 5, wherein said oxide mixture consists essentially of:
MgO, CaO, SrO and BaO in amounts which total 25 to 40 mol % of the oxide mixture with 13.0 to 15.5 mol % of BaO; TiO2 and ZrO2 in amounts which total 7 to 24 mol % of the oxide mixture; and
7. A glass fiber forming composition as set forth in claim 5, said composition consisting essentially of 0 to 15 mol % of at least one oxide selected from the group consisting of TaO2.5, LaO1.5, CeO2, ZnO, Li2 O, Na2 O, K2 O, MnO2, and BO1.5, and 85-100 mol % of an oxide mixture, said oxide mixture consisting essentially of:
MgO, CaO, SrO and BaO, in amounts which total 28 to 35 mol % of the oxide mixture, with 0 to 4 mol % of MgO, 6.5 to 9.3 mol % of CaO, 6.0 to 7.75 mol % of SrO 13.0 to 15.5 mol % of BaO;
TiO2 and ZrO2 in amounts which total 9.05 to 21 mol % of the oxide mixture with 7.45 to 17.33 mol % of TiO2 and 1.6 to 3.67 mol % of ZrO2 ; and
This is a continuation of application Ser. No. 07/832,267, filed Feb. 7, 1992, (now U.S. Pat. No. 5,284,807).
The need for high speed and high frequency information transmission is becoming more and more pronounced with the recent development of sophisticated information systems. In the field of mobile communication by car telephones and personal radios as well as new media of satellite broadcasting and cable television network, there has been an increasing demand of miniaturizing electronic devices and also microwave circuit elements such as dielectric resonators utilized in combination with the electronic devices. The size of the microwave circuit elements is determined in dependance upon the wavelength of all applied electromagnetic wave. It is known that the wavelength λ of the electromagnetic wave propagating through a dielectric body having a dielectric constant of ε.sub.Γ is λ=λ0 /(ε.sub.Γ)0.5 wherein λ0 is propagation wavelength in vacuum. Therefore, the microwave circuit elements can be made more compact when utilizing a circuit board or substrate having a higher dielectric constant. In addition, the use of the circuit board of higher dielectric constant is advantageous in that it acts to concentrate the electromagnetic energy within the board and thereby minimize the leakage of the electromagnetic wave. Ill order to give a high dielectric constant to the circuit board, there have been utilized in the art;
1) to fabricate the circuit board from a resin of high dielectric constant, for example, polyvinylidene fluoride (ε.sub.Γ =13) and cyano resin (ε.sub.Γ =16 to 20);
In order to eliminate the above problems, the inventors have noted a glass composition including SiO2, BaO, TiO2 and ZrO2 which is a lead-less composition and shows a good dielectric characteristic as well as excellent chemical durabilities, for example, acid-proof, alkali-proof and water resisting property. However, this glass composition has a relatively high devitrification temperature and is therefore found difficult to be spun into corresponding glass fibers. Spinning or fabrication of the glass fibers is generally effected by drawing the melted glass composition through 200 to 800 minute nozzles in the bottom of a platinum pot (generally called as a bushing). In this process, the glass composition of high devitrification temperature undergoes crystallization on the bottom of the bushing due to the devitrification, which hinders smooth drawing of the composition and therefore suffers the breakage of the resulting glass fibers. For successfully fabricating the glass fibers, it has been a general practice to control the temperature of the bushing's bottom as well as to control a winding speed of the resulting glass fibers in an attempt to avoid the devitrification. Nevertheless, even the above control becomes ineffective when the devitrification temperature of the glass composition is higher than a temperature at which the composition has a viscosity of 102.5 (316) poise. In other words, the control is not possible at a very low viscosity of the melted glass composition. In view of the above, the glass composition of SiO2 -BaO-TiO2 -ZrO2 is found not to be suitable for forming the glass fibers because of its higher devitrification temperature than 102.5 poise temperature, although it shows a superior dielectric constant [ε.sub.Γ ] of as high as 9 or more.
Based upon the above recognitions, much studies have been concentrated on examining an optimum glass composition which not only exhibits a superior dielectric characteristic as well as chemical durabilities but also is capable of being readily formed into glass fibers, and have revealed that a particular glass composition with a high dielectric constant [ε.sub.Γ ] as well as low dielectric loss tangent [tan δ] can be improved so as to be readily spun into corresponding glass fibers by the addition of a suitable proportion of Nb2 O5. Through a further investigation into an optimum glass composition incorporating Nb2 O5, the present invention has been accomplished.
Accordingly, it is a primary object of the present invention to provide a glass fiber forming composition which is capable of readily spun into glass fibers, yet retaining desired high dielectric constant [ε.sub.Γ ] and low dielectric loss tangent [tan δ], in addition to superior chemical durabilities.
The composition is further characterized to include at least 85 mol % of a total amount of the oxides and have a dielectric constant [ε.sub.Γ ] of 9 or more at 1 MHz and 25° C., and to have a devitrification temperature lower than a spinning temperature at which the glass composition exhibits viscosity of 102.5 poise so as to be readily spun into corresponding glass fibers. Thus prepared glass composition is found to have excellent characteristics as follows:
1) High dielectric constant [ε.sub.Γ ] of 9 or more at 1 MHz and 25° C.;
3) High dielectric constant [ε.sub.Γ ] and low dielectric loss tangent [tan δ] can be maintained without causing critical changes in these values even at 100 MHz or more;
Nb2 O5 is essential in that it lowers remarkably the devitrification temperature, However, it is found that a desired effect is not expected below 0.5 mol % of NbO5/2 and that the devitrification temperature will adversely raised when it is added in more than 15 mol %. Thus, the proportion of NbO5/2 is limited to be within a range of 0.5 to 15 mol %.
0.5 to 15 mol % of NbO5/2 as calculated from an incorporated amount of Nb2 O5 ; and 0.5 to 15 mol % of
AlO3/2 as calculated from an incorporated amount of Al2 O3.
The glass composition is also characterized to incorporate at least 85 mol % of a total amount of the oxides and has a dielectric constant [ε.sub.Γ] of 9 or more at 1 MHz and 25° C., and to show a devitrification temperature which is remarkably lower than a spinning temperature at which said composition exhibits a viscosity of 102.5 poise.
The resin is preferably made of a PPO composition composed of PPO (polyphenylene oxide) and at least one of cross-linking polymer and cross-linking monomer, as expressed by a general formula: ##STR1## wherein each R represents hydrogen or hydrocarbon group having 1 to 3 carbon atoms and may be a different hydrocarbon group from each other. One example of PPO is poly (2.6-dimethyl-1.4-phenylene oxide) which may be synthesized by a manner as disclosed in U.S. Pat. No. 4,059,568. It is preferred but not in a limited sense that PPO is selected to have a weight-average molecular weight [Mw] of 50,000 and a molecular-weight distribution [Mw/Mn] of 4.2 in which Mn is a number-average molecular weight.
Included in the cross-linking polymer are, for example, 1.2-poly butadiene, 1.4-poly butadiene, styrene-butadiene copolymer, denatured 1.2-poly butadiene (maleine-, acryl- and epoxy-denatured) and rubbers, although not limited thereto. The cross-linking polymer may be utilized singly or in combination and may be polymerized in the form of either elastomer or rubber. Also, polystyrene may be added to the cross-linking polymer in such an amount as not to suppress the desired characteristics of the resin.
The resin may incorporate a number of inorganic dielectric particles which are dispersed in the resin layer to further increase the dielectric constant of the circuit board. When non-porous dielctric particles are utilized, the particles are preferred to have an average particle size of 1 to 5 μm with a specific surface area of 0.2 to 3.0 m2 /g for reason that the particles can be readily and uniformly dispersed in the resin. To further increase the dielectric constant, it is most preferred to utilize porous dielectric particles having minute pores, voids, cracks or the like openings in the outer surface into which the resin can easily permeate. The porous dielectric particles are preferred to have an average particle size of 5 to 100 μm with a specific surface area of 0.3 to 7.0 m2 /g. Above 100 μm particle size, the particles are likely to bring about uneven surface configuration of the resin layer or the circuit board, so as to lower moisture proof (water proof) property, to degrade dielectric loss tangent (tan δ), and even to suffer particle breakage in the fabrication process of the circuit board leading to undesired variation in dielectric characteristics. Above 7.0 m2 /g specific surface area, the particles will lower moisture proof (water proof) property and degrade dielectric loss tangent (tan δ). Below 0.2 m2 /g specific surface area, the particles are not expected to increase dielectric dielectric constant of the circuit board. The porous inorganic dielectric particles may be preferably agglomerated particles which are formed from corresponding primary particles to have pores, voids or like opening between the primary particles. The primary particles are preferably combined physically and chemically by sintering.
Preferably, the porous inorganic dielectric particles may include compounds of high dielectric constant having a perovskite or complex perovskite crystalline structure. For example, dielectric particle of such structures includes BaTiO3, SrTiO3, PbTi1/2 Zr1/2 O3, Pb(Mg2/3 Nb1/3)O3, Ba(Snx Mgy Taz)O3, and Ba(Zrx Zny Taz)O3. Besides, the porous inorganic dielectric particle may be oxides or complex oxides of TiO2, ZrO2, and SnO2. The porous inorganic dielectric particles may be provided in the form of globular, various block configuration or any other configurations. The circuit board, which is fabricated from a resin to incorporate the dielectric particles together with the glass fibers in accordance with the present invention, is selected to have 25 to 95 vol % of the resin, 5 to 75 vol % of the dielectric particles, and 5 to 70 vol % of the glass fibers. The use of the porous dielectric particles is found particularly effective for increasing dielectric constant [ε.sub.Γ ] in that the pores of the particles appear to provide more spaces of high dielectric constant as compared to non-porous particles, in that the porous particles are reluctant to sink in a resin varnish to be thereby readily mixed with the resin for facilitating the fabrication of the circuit board, and also in that the porous particles can be readily fractured at the time of drilling or cutting the resulting circuit board to thereby facilitate the circuit board processing.
When sintering to obtain the dielectric secondary particles from the primary particles, it is preferred to employ a sintering aid of any kind which will not damage the dielectric characteristic and yield sufficient reinforcing effect. The sintering aid is incorporated in a suitable proportion depending upon a desired effect and also upon the kinds of the aid. Generally, the aid is preferably incorporated in 0.1 to 5 wt % based upon the weight of the dielectric particles and has an average particle size of 0.01 to 100 μm, preferably of 0.1 to 50 μm for a uniformly dispersing purpose. The sintering aid includes BaO-SiO2 -B2 O3, CaO-SiO2 -B2 O3, Li2 O-SiO2 -B2 O3, Li2 O-Al2 O3 -SiO2, Na2 O-Al2 O3 -SiO2, Li2 O-GeO2, CdO-PbO-SiO2, Li2 O-SiO2, B2 O3 -Bi2 O3, PbO-SiO2 -BaO, Na2 O-PbO-SiO2, PbO-GeO2, CuO, Bi2 O3, B2 O3, CdO, Li2 O, PbO, WO3, Pb5 Ge3 O11, Li2 SiO3, LiF, CuF2, ZnF2, and CaF2.
With the addition of the sintering aid, it is possible not only to facilitate the sintering but also to strengthen the dielectric particles for avoiding collapsing thereof at the time of fabricating the circuit board, to lower the sintering temperature so as to enable the formation of porous dielectric particles of relatively large pores, thereby increasing the dielectric constant [ε.sub.Γ ] of the circuit board.
0.5 to 15 mol % of AlO3/2 a as calculated from an incorporated amount of Al2 O3.
The glass plates were cut and polished to present corresponding sample specimens which were then formed on both sides thereof with gold electrodes by vacuum evaporation and measured with regard to dielectric constant [ε.sub.Γ ] and dielectric loss tangent [tan δ] by an impedance analyzer at 25° C. for respective frequencies of 1 MHz and 1 GHz.
TABLE 1__________________________________________________________________________           Example                Example                     Example                          Example                               Example                                    Example                                         Example                                              Example           1    2    3    4    5    6    7    8__________________________________________________________________________Composition    SiO2           50.0 50.0 50.0 50.0 50.0 50.0 50.0 50.0(mol %)  CaO    7.5  7.5  7.5  7.5  7.5  7.5  7.5  9.0    SrO    7.5  7.5  7.5  7.5  7.5  7.5  7.5  6.0    BaO    15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0    MgO    --   --   --   --   --   --   --   --    TiO2           9.08 10.73                     11.55                          10.7 12.38                                    13.2 14.85                                              11.55    ZrO2           1.92 2.27 2.45 3.3  2.62 2.8  3.15 2.45    NbO5/2           9.0  7.0  6.0  6.0  5.0  4.0  2.0  6.0dielectric constant εr (1 MHz)           11.7 11.6 11.6 11.2 11.5 11.5 11.5 11.5dielectric constant εr (1 GHz)           11.7 11.6 11.6 11.2 11.5 11.5 11.5 11.5dielectric loss tan δ [%] (1 MHz)           0.08 0.08 0.09 0.09 0.08 0.08 0.09 0.08dielectric loss tan δ [%] (1 GHz)           0.31 0.30 0.29 0.28 0.30 0.30 0.29 0.30102.5 poise temp. Tx (°C.)           1147 1150 1153 1152 1155 1151 1158 1149devitrification temp, Ty (°C.)           1080 1071 1070 1090 1080 1095 1120 1066(Tx-Ty) °C.           67   79   83   62   75   56   38   83glass fiber forming feasibility           good good good good good good good good__________________________________________________________________________
TABLE 2__________________________________________________________________________           Example                Example                     Example                          Example                               Example                                    Example                                         Example           9    10   11   12   13   14   15__________________________________________________________________________Composition    SiO2           52.5 52.5 55.0 55.0 55.0 49.0 49.02(mol %)  CaO    9.3  7.75 7.5  7.5  7.5  7.3  7.35    SrO    6.2  7.75 7.5  7.5  7.5  7.3  7.35    BaO    15.5 15.5 15.0 15.0 15.0 14.6 14.71    MgO    --   --   --   --   --   --   --    TiO2           9.53 9.53 8.7  9.28 9.9  14.5 14.56    ZrO2           2.02 2.02 1.8  1.97 2.1  3.4  3.09    NbO5/2           4.95 4.95 4.5  3.75 3.0  3.9  3.92dielectric constant εr (1 MHz)           11.0 10.9 10.5 10.5 10.4 11.8 11.9dielectric constant εr (1 GHz)           10.9 10.9 10.5 10.4 10.4 11.8 11.8dielectric loss tan δ [%] (1 MHz)           0.07 0.07 0.08 0.07 0.07 0.09 0.08dielectric loss tan δ [%] (1 GHz)           0.29 0.29 0.27 0.28 0.28 0.29 0.30102.5 poise temp, Tx (°C.)           1164 1168 1180 1173 1175 1157 1145devitrification temp. Ty (°C.)           1096 1124 1126 1130 1117 1112 1102(Tx-Ty) °C.           68   44   54   43   58   45   43glass fiber forming feasibility           good good good good good good good__________________________________________________________________________
TABLE 3__________________________________________________________________________           Example 16                 Example 17                       Example 18                             Example 19__________________________________________________________________________Composition    SiO2           47.16 50.0  50.0  50.0(mol %)  CaO    7.03  6.5   7.5   6.9    SrO    7.03  6.5   7.5   6.9    BaO    14.05 13.0  15.0  13.7    MgO    --    4.0   --    --    TiO2           13.95 14.85 11.5  11.5    ZrO2           3.27  3.15  2.5   2.5    NbO5/2           7.51  2.0   4.5   6.0    TaO5/2           --    --    1.5   --    LaO3/2           --    --    --    2.5dielectric constant εr (1 MHz)           12.3  11.2  11.2  11.4dielectric constant εr (1 GHz)           12.3  11.2  11.2  11.4dielectric loss tan δ [%] (1 MHz)           0.08  0.10  0.07  0.09dielectric loss tan δ [%] (1 GHz)           0.31  0.30  0.30  0.31102.5 poise temp. Tx (°C.)           1136  1149  1153  1145devitrification temp. Ty (°C.)           1085  1095  1090  1115(Tx-Ty) °C.           51    54    63    30glass fiber forming feasibility           good  good  good  good__________________________________________________________________________
TABLE 4__________________________________________________________________________           Example 20                 Example 21                       Example 22                             Example 23                                   Example 24__________________________________________________________________________Composition    SiO2           50.0  50.0  50.0  50.0  40.0(mol %)  CaO    6.9   6.9   6.8   7 5   9.0    SrO    6.9   6.9   6.8   7.5   6.0    BaO    13.7  13.7  13.4  15.0  15.0    MgO    --    --    --    --    --    TiO2           11.5  11.5  11.5  7.45  17.33    ZrO2           2.5   2.5   2.5   1.6   3.67    NbO5/2           6.0   6.0   6.0   11.0  9.0    CeO2           2.5   --    --    --    --    ZnO    --    2.5   --    --    --    Li2 O           --    --    1.0   --    --    Na2 O           --    --    1.0   --    --    K2 O           --    --    1.0   --    --dielectric constant εr (1 MHz)           11.5  11.1  11.1  11.7  14.1dielectric constant εr (1 GHz)           11.5  11.1  11.1  11.6  14.1dielectric loss tan δ [%] (1 MHz)           0.08  0.09  0.05  0.08  0.11dielectric loss tan δ [%] (1 GHz)           0.30  0.30  0.22  0.30  0.31102.5 poise temp. Tx (°C.)           1145  1136  1080  1142  1090devitrification temp. Ty (°C.)           1118  1130  1078  1140  1089(Tx-Ty) °C.           27    6     2     2     1glass fiber forming feasibility           good  good  good  good  good__________________________________________________________________________
TABLE 5__________________________________________________________________________           Example                Example                     Example                          Example                               Example                                    Example                                         Example                                              Example           25   26   27   28   29   30   31   32__________________________________________________________________________Composition    SiO2           55.0 50.0 50.0 50.0 50.0 50.0 48.0 50.0(mol %)  CaO    9.0  9.0  9.0  7.5  9.0  6.8  9.0  6.9    SrO    6.0  6.0  6.0  7.5  6.0  6.8  6.0  6.9    BaO    15.0 15.0 15.0 15.0 15.0 13.4 15.0 13.7    TiO2           7.8  9.9  9.5  9.5  9.1  11.5 9.1  11.5    ZrO2           1.7  2.1  2.0  2.0  1.9  2.5  1.9  2.5    NbO5/2           3.0  6.0  6.0  6.0  6.0  6.0  6.0  6.0    AlO3/2           2.5  2.0  2.5  2.5  3.0  3.0  5.0  2.5dielectric constant εr (1 MHz)           10.1 11.2 11.1 11.1 11.0 11.0 11.0 11.0dielectric constant εr (1 GHz)           10.1 11.2 11.1 11.1 11.0 11.0 11.0 11.0dielectric loss tan δ [%] (1 MHz)           0.07 0.08 0.08 0.08 0.08 0.08 0.08 0.09dielectric loss tan δ [%] (1 GHz)           0.27 0.29 0.29 0.29 0.28 0.28 0.28 0.28102.5 poise temp. Tx (°C.)           1199 1154 1162 1160 1166 1164 1160 1158devitrification temp. Ty (°C.)           1085 1054 1063 1065 1060 1064 1057 1070(Tx-Ty) °C.           114  100  99   95   106  100  103  88glass fiber forming feasibility           excellent                excellent                     excellent                          excellent                               excellent                                    excellent                                         excellent                                              excellent__________________________________________________________________________
TABLE 6__________________________________________________________________________           Comparative Example 1                       Comparative Example 2                                   Comparative Example__________________________________________________________________________                                   3Composition    SiO2           40.0        50.0        50.0(mol %)  CaO    7.5         7.5         9.0    SrO    7.5         7.5         6.0    BaO    15.0        15.0        15.0    MgO    --          --          11.5    TiO2           23.0        16.5        2.5    ZrO2           7.0         3.5         --    NbO5/2           --          --          --    AlO3/2           --          --          6.0dielectric constant εr (1 MHz)           13.5        11.0        10.6dielectric constant εr (1 GHz)           13.5        11.0        10.6dielectric loss tan δ [%] (1 MHz)           0.13        0.09        0.09dielectric loss tan δ [%] (1 GHz)           0.32        0.29        0.30102.5 poise temp. Tx (°C.)           1077        1147        1176devitrification temp. Ty (°C.)           1214        1204        1203(Tx-Ty) °C.           -137        -57         -27glass fiber forming feasibility           not acceptable                       not acceptable                                   not acceptable__________________________________________________________________________
As concluded from the listed results of Tables 1 to 6, the glass composition of Examples 1 to 32 exhibit desired dielectric characteristics for use in a circuit board and can be readily spun into the glass fibers. In contrast, the glass fiber are not available from Comparative Example 1 lacking Nb2 O5 and incorporating excess amounts of TiO2 and ZrO2, Comparative Example 2 lacking Nb2 O5, and Comparative Example 3 incorporating Al2 O3 but not Nb2 O5. For all of Comparative Examples 1 to 3, the devitrification temperature Ty is higher than the 102.5 poise temperature Tx in contrast to Examples 1 to 32. Thus, the relation [Tx-Ty] between the devitrification temperature and 102.5 poise temperature is found to well indicative of the glass fiber forming feasibility. Also, it is confirmed that Al2 O3 alone will not impart the glass fiber forming feasibility.
TABLE 7__________________________________________________________________________         Examples(by weight parts)         34 & 47               35 & 48                    36 & 49                         37 & 50                              38 & 51                                     39 & 52__________________________________________________________________________PPO (poly-phenylene-oxide)         110   40   110  40   110    110cross-linking polymer         SBS #1)               SBS  SBS  SBS  p-TAIC #3)                                     --         80 parts               120 parts                    80 parts                         120 parts                              90 partscross-linking monomer         TAIC #2)               TAIC TAIC TAIC --     TAIC         10 parts               40 parts                    10 parts                         40 parts    90 partsinitiator #4) 4     4    4    4    4      4porous dielectric particles         470   470  470  470  470    470solvent (trichloroethylene)         1000  1000 1000 1000 1000   1000__________________________________________________________________________ #1) SBS is for styrene butadiene copolymer #2) TAIC for triallylisocyanate #3) pTAIC for polymer of TAIC, #4) 25-dimethyl-2-5-di-(tert-butylperoxy)hexyne-3 [sold under the tradename of Perhexyne 25B from Nippon Yushi KK]
A double-sided circuit board was fabricated in the identical manner as in Example 33 except for dielectric particles. The dielectric particles utilized here were prepared by wet-blending 500 g of Ba0.7 Sr0.3 TiO3 having an average particle size of 0.1 μm, 1.7 g of CuO, and 50 ml of 5 wt % solution of polyvinyl alcohol in 1 l of ion exchanged water, spray-granulating it into corresponding granules of primary particles, and then sintering the granules at 1000° C. for 2 hours. The resulting porous dielectric particles were agglomerated or secondary particles from the primary particles and have an average particle size of 21 μm and a specific surface area of 1.3 m2 /g.
The circuit boards of Examples 33 to 58 and Comparative Examples 4 and 5 were examined with regard to dielectric constant [ε.sub.Γ ], dielectric loss tangent [tan δ], peel strength, solder resistance at 260° C. The results are listed in Table 8. To determine the solder resistance, the circuit boards of the Examples and the comparative Examples were cut into 30×30 mm specimens. Three specimens of the same kind were floated on a melted solder maintaining at 260° C. for 25, 45, and 60 seconds, respectively and then withdrawn therefrom to observe whether the specimens suffers any warp, blister, or like deformation. The solder resistance was then evaluated in terms of the time [seconds] during which the deformation appeared in the specimens. That is, solder resistance of 25 sec., as listed in Table 8, means that the specimen suffers the deformation after being floated on the solder of 260° C. for 25 seconds or less and solder resistance of 60 or more means that the specimen sees no substantial deformation even after being exposed to the solder of 260° C. for 60 seconds.
TABLE 8__________________________________________________________________________       dielectric constant                dielectric loss solder resistance       εr                tan δ (%)                         peel strength                                at 260° C.       1 MHZ            1 GHz                1 MHz                     1 GHz                         [kg/cm]                                [seconds]__________________________________________________________________________Example 33  20.5 20.4                0.32 0.60                         2.3    25Comparative Example 4       21.4 21.2                0.33 0.80                         2.3    25Comparative Example 5       16.5 16.5                0.33 0.60                         2.3    25Example 34  20.0 20.0                0.32 0.60                         2.1    60 or moreExample 35  19.6 19.5                0.31 0.59                         2.0    60 or moreExample 36  20.2 20.1                0.30 0.58                         2.0    60 or moreExample 37  20.2 20.1                0.30 0.57                         2.3    60 or moreExample 38  20.5 20.4                0.31 0.58                         2.4    60 or moreExample 39  20.4 20.3                0.34 0.62                         2.3    60 or moreExample 40  13.0 13.0                0.28 0.55                         2.3    25Example 41  12.7 12.7                0.28 0.53                         2.3    25Example 42  10.2 10.2                0.28 0.42                         2.3    25Example 43  20.3 20.3                0.32 0.59                         2.3    25Example 44  25.0 25.0                0.35 0.62                         2.3    25Example 45  24.3 24.3                0.35 0.62                         2.2    25Example 46  20.2 20.1                0.32 0.60                         2.3    25Example 47  19.8 19.7                0.31 0.59                         2.1    60 or moreExample 48  19.4 19.3                0.31 0.58                         2.0    60 or moreExample 49  20.2 19.9                0.30 0.58                         2.0    60 or moreExample 50  20.2 19.9                0.30 0.57                         2.3    60 or moreExample 51  20.3 20.2                0.30 0.57                         2.4    60 or moreExample 52  20.2 20.1                0.33 0.62                         2.3    60 or moreExample 53  12.8 12.8                0.27 0.54                         2.3    25Example 54  12.5 12.5                0.27 0.52                         2.3    25Example 55  10.1 10.1                0.27 0.41                         2.3    25Example 56  20.0 20.0                0.32 0.59                         2.3    25Example 57  24.8 24.8                0.35 0.62                         2.3    25Example 58  24.1 24.1                0.35 0.62                         2.2    25__________________________________________________________________________
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2 Patent Abstracts of Japan, vol. 13, No. 461 (C-645) 18 Oct. 1989 & JP-A-01 179 741, Jul. 17, 1989.
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U.S. Classification 501/35, 501/38, 501/70, 501/72
International Classification C03C13/00, H05K1/03
Cooperative Classification C03C3/102, H05K1/0326, C03C13/00, H05K2201/0209, C03C3/091, C03C3/097, H05K1/0366, H05K1/0373, H05K2201/0116
European Classification C03C3/097, C03C3/102, C03C3/091, H05K1/03C4C, C03C13/00, H05K1/03C4D, H05K1/03C2B