Source: http://www.google.com/patents/US5284807?dq=7,007,239
Timestamp: 2014-03-16 00:13:58
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Patent US5284807 - Glass fiber forming composition, glass fibers obtained from the composition ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA glass fiber forming composition exhibits a remarkably high dielectric constant ε.sub.r 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...http://www.google.com/patents/US5284807?utm_source=gb-gplus-sharePatent US5284807 - Glass fiber forming composition, glass fibers obtained from the composition and substrate for circuit board including the glass fibers as reinforcing materialAdvanced Patent SearchPublication numberUS5284807 APublication typeGrantApplication numberUS 07/832,267Publication dateFeb 8, 1994Filing dateFeb 7, 1992Priority dateFeb 8, 1991Fee statusPaidAlso published asCA2060709A1, CA2060709C, DE69210270D1, DE69210270T2, EP0498425A1, EP0498425B1, US5334645, US5407872Publication number07832267, 832267, US 5284807 A, US 5284807A, US-A-5284807, US5284807 A, US5284807AInventorsKiyotaka Komori, Tadashi Kukubo, Jun Naka, Seishiro Yamakawa, Shigeru YamamotoOriginal AssigneeMatsushita Electric Works, Ltd., Nippon Electric Glass Co., Ltd.Export CitationBiBTeX, EndNote, RefManPatent Citations (12), Non-Patent Citations (4), Referenced by (31), Classifications (22), Legal Events (5) External Links: USPTO, USPTO Assignment, EspacenetGlass fiber forming composition, glass fibers obtained from the composition and substrate for circuit board including the glass fibers as reinforcing materialUS 5284807 AAbstract A glass fiber forming composition exhibits a remarkably high dielectric constant ε.sub.r 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 10.sup.2.5 poise, so as to be readily spun into corresponding glass fibers. The composition consists essentially of 40 to 65 mol % of SiO.sub.2 ; 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 TiO.sub.2 and ZrO.sub.2 ; and 0.5 to 15 mol % of NbO.sub.5/2 as calculated from an incorporated amount of Nb.sub.2 O.sub.5. Alternately, the composition consist essentially of 40 to 65 mol % of SiO.sub.2 ; 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 TiO.sub.2 and ZrO.sub.2 ; 0.5 to 15 mol % of NbO.sub.5/2 as calculated from an incorporated amount of Nb.sub.2 O.sub.5 ; and 0.5 to 15 mol % of AlO.sub.3/2 as calculated from an incorporated amount of Al.sub.2 O.sub.3. 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.r ] of 9 or more at 1 MHz and 25
What is claimed is: 1. A glass fiber obtained from a glass composition which consists essentially of 0 to 15 mol % of at least one oxide selected from the group consisting of TaO.sub.2.5, LaO.sub.1.5, CeO.sub.2, ZnO, Li.sub.2 O, Na.sub.2 O, K.sub.2 O, MnO.sub.2, and BO.sub.1.5 and 85-100 mol % of an oxide mixture, said oxide mixture consisting essentially of:40 to 65 mol % of SiO.sub.2 ; CaO, SrO and BaO in amounts which total 20 to 45 mol % of the oxide mixture; TiO.sub.2 and ZrO.sub.2 in amounts which total 5 to 25 mol % of the oxide mixture; and 0. 5 to 15 mol % of NbO.sub.5/2said composition having a dielectric constant ε.sub.r of 9 or more at 1 MHz and 25 show a devitrification temperature which is lower than a spinning temperature at which said composition exhibits a viscosity of 10.sup.2.5 poise. 2. A glass fiber obtained from a glass composition which consists essentially of 0 to 15 mol % of at least one oxide selected from the group consisting of TaO.sub.2.5, LaO.sub.1.5, CeO.sub.2, ZnO, Li.sub.2 O, Na.sub.2 O, K.sub.2 O, MnO.sub.2, and BO.sub.1.5 and 85-100 mol % of an oxide mixture, said oxide mixture consisting essentially of:40 to 65 mol % of SiO.sub.2 ; CaO, SrO and BaO in amounts which total 20 to 45 mol % of the oxide mixture; TiO.sub.2 and ZrO.sub.2 in amounts which total 5 to 25 mol % of the oxide mixture; 0.5 to 15 mol % of NbO.sub.5/2 ; and 0.5 to 15 mol % of AlO.sub.3/2 ; said composition having a dielectric constant ε.sub.r of 9 or more at 1 MHz and 25 show a devitrification temperature which is lower than a spinning temperature at which said composition exhibits a viscosity of 10.sup.2.5 poise. 3. A glass fiber obtained from a glass composition which consists essentially of 0 to 15 mol % of at least one oxide selected from the group consisting of TaO.sub.2.5, LaO.sub.1.5, CeO.sub.2, ZnO, Li.sub.2 O, Na.sub.2 O, K.sub.2 O, MnO.sub.2, and BO.sub.1.5 and 85-100 mol % of an oxide mixture, said oxide mixture consisting essentially of40 to 65 mol % of SiO.sub.2 ; MgO, CaO, SrO and BaO in amounts which total 20 to 45 mol % of the oxide mixture; TiO.sub.2 and ZrO.sub.2 in amounts which total 5 to 25 mol % of the oxide mixture; 0.5 to 15 mol % of NbO.sub.2.5 ;said composition having a dielectric constant ε.sub.r of 9 or more at 1 MHz and 25 show a devitrification temperature which is lower than a spinning temperature at which said composition exhibits a viscosity of 10.sup.2.5 poise. 4. A glass fiber as set forth in claim 1, wherein said oxide mixture, consists essentially of:46 to 60 mol % of SiO.sub.2 ; 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; TiO.sub.2 and ZrO.sub.2 in amounts which total 7 to 24 mol % of the oxide mixture; and 1 to 10 mol % of NbO.sub.5/2. 5. A glass fiber as set forth in claim 3, wherein said oxide mixture consists essentially of:46 to 60 mol % of SiO.sub.2 ; 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; TiO.sub.2 and ZrO.sub.2 in amounts which total 9.05 to 21 mol % of the oxide mixture, with 7.45 to 17.33 mol % of TiO.sub.2 and 1.6 to 3.67 mol % of ZrO.sub.2 ; and 2 to 9 mol % of NbO.sub.5/2. 6. A glass fiber as set forth in claim 2, wherein said oxide mixture consists essentially of:46 to 60 mol % of SiO.sub.2 ; 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; TiO.sub.2 and ZrO.sub.2, in amounts which total 9.5 to 14 mol % of the oxide mixture, with 7.8 to 11.5mol % of TiO.sub.2 and 1.7 to 2.5 mol % of ZrO.sub.2 ; 1 to 10 mol % of NbO.sub.5/2 ; and 1 to 10 mol % of AlO.sub.3/2. 7. A glass fiber as set forth in claim 3, wherein said oxide mixture consists essentially of:46 to 60 mol % of SiO.sub.2 ; 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; TiO.sub.2 and ZrO.sub.2 in amounts which total 7 to 24 mol % of the oxide mixture; and 1 to 10 mol % of NbO.sub.2.5. Description
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 an 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.r is λ=λ.sub.0 /(ε.sub.r).sup.0.5 wherein λ.sub.0 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. In 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.r =13) and cyano resin (ε.sub.r =16 to 20);
2) to fabricate the circuit board from a suitable resin and disperse therein inorganic particles of high dielectric constant, for example, TiO.sub.2 and BaTiO.sub.3 particles; and
The circuit board dispersed with the inorganic dielectric particles is likely to have uneven dispersion of the particles leading to correspondingly uneven distribution of dielectric constant on the surface of the board. For this reason, the circuit board of this type is found to be also unsatisfactory. Consequently, the circuit board reinforced by the glass fibers or glass cloth is found desirable. In addition, the glass fiber reinforced circuit board is also found advantageous because of its economy and of easy workability such as cutting and drilling. The conventional glass fiber reinforced circuit board normally utilizes a glass cloth made of E-glass which is composed of SiO.sub.2, Al.sub.2 O.sub.3 and CaO and exhibits less dielectric constant of about 6 to 7. In place of the E-glass, there have been proposed lead glass of rather high dielectric constant. For example, lead glass consisting of 72 wt % of PbO, 26 wt % of SiO.sub.2 and 1.5 wt % of B.sub.2 O.sub.3 and 0.5 wt % of K.sub.2 O shows a dielectric constant of 13.0 sufficient to fabricate the circuit board of desired dielectric characteristics. However, such lead glass composition is found difficult to be spun into fibers of 7 to 9 μm in diameter since PbO will evaporate violently at the time of melting to thereby become less uniform in composition and therefore frequently bring about breakage of thread or fibers in the spinning process. In addition, the lead glass composition is not suitable for forming a glass cloth of fibers for use in the circuit board, since the lead glass composition has inherently low strain point and therefore easily deteriorates in a heating process of removing a primary binder which is essential in forming the glass cloth. Thus, the lead glass composition is permitted to be heat-treated only to a limited extent and is therefore not sufficiently removed of the primary binder, which lowers long-term reliability of the circuit board including the glass cloth formed from the lead glass. Further, due to the toxic nature of the lead, the lead glass composition must be handled carefully and is therefore rather inconvenient and not adequate for fabrication of the glass fiber or glass cloth thereof. Furthermore, due to large dielectric loss tangent (tan δ), the lead glass composition is not adequate for the circuit board for high frequency use.
SUMMARY OF THE INVENTION In order to eliminate the above problems, the inventors have noted a glass composition including SiO.sub.2, BaO, TiO.sub.2 and ZrO.sub.2 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 10.sup.2.5 (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 SiO.sub.2 --BaO--TiO.sub.2 --ZrO.sub.2 is found not to be suitable for forming the glass fibers because of its higher devitrification temperature than 10.sup.2.5 poise temperature, although it shows a superior dielectric constant [ε.sub.r ] 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.r ] 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 Nb.sub.2 O.sub.5. Through a further investigation into an optimum glass composition incorporating Nb.sub.2 O.sub.5, 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.r ] and low dielectric loss tangent [tan δ], in addition to superior chemical durabilities.
40 to 65 mol % of SiO.sub.2 ;
5 to 25 mol % of at least one selected from the group consisting of TiO.sub.2 and ZrO.sub.2 ; and
0.5 to 15 mol % of NbO.sub.5/2 as calculated from an incorporated amount of Nb.sub.2 O.sub.5.
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.r ] of 9 or more at 1 MHz and 25 temperature lower than a spinning temperature at which the glass composition exhibits viscosity of 10.sup.2.5 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.r ] of 9 or more at 1 MHz and 25
2) Low dielectric loss tangent [tan δ] of 0.6% or less at 1 MHz and 25
3) High dielectric constant [ε.sub.r ] and low dielectric loss tangent [tan δ] can be maintained without causing critical changes in these values even at 100 MHz or more;
5) High strain point of about 600
SiO.sub.2 is essential in the glass composition as a major glass network former and should be incorporated in the above listed proportion (40 to 65 mol %) because of that, with SiO.sub.2 proportion of less than 40 mol %, the glass composition suffers a raised devitrification temperature and a lowered viscosity not suitable to form glass fibers, in addition to that the glass composition is given only poor chemical durability, and also because of that, with SiO.sub.2 proportion of more than 65 mol %, the glass composition is difficult to have a desired high dielectric constant of 9 or more as well as suffers high glass viscosity not suitable to be formed into glass fibers.
TiO.sub.2 and ZrO.sub.2 are essential singly or in combination to increase the dielectric constant as well as to improve the chemical durabilities. It is preferred that the above components are utilized in combination and further that TiO.sub.2 is incorporated in a more amount than ZrO.sub.2. Below 5 mol % of at least one of TiO.sub.2 and ZrO.sub.2, the resulting glass composition is difficult to attain a desired dielectric constant of 9 and to improve the chemical durabilities. Above 25 mol %, the resulting glass composition suffers from so raised devitrification temperature as to disable the spinning into glass fibers. Thus, the total proportion of TiO.sub.2 and ZrO.sub.2 is limited to be within a range of 5 to 25 mol %.
Nb.sub.2 O.sub.5 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 NbO.sub.5/2 and that the devitrification temperature will adversely raised when it is added in more than 15 mol %. Thus, the proportion of NbO.sub.5/2 is limited to be within a range of 0.5 to 15 mol %.
Preferably, the glass composition contains 46 to 60 mol % of SiO.sub.2, 25 to 40 mol % of at least one selected from the group consisting of MgO, CaO, SrO and BaO, 7 to 24 mol % of at least one selected from the group consisting of TiO.sub.2 and ZrO.sub.2, and 1 to 10 mol % of NbO.sub.5/2 as calculated from an incorporated amount of Nb.sub.2 O.sub.5. Most preferably, the composition incorporates 28 to 35 mol % of at least one selected from the group consisting of MgO, CaO, SrO and BaO and 2 to 9 mol % of NbO.sub.5/2.
The total amount of the above-mentioned glass forming oxides should be incorporated in at least 85 mol %. Otherwise, the glass composition fails to show a desired dielectric constant of at least 9 as well as to be properly spun into glass fibers. The glass composition of the present invention may additionally incorporate up to 15 mol % of at least one of suitable oxides such as TaO.sub.5/2, AlO.sub.3/2, LaO.sub.3/2, CeO.sub.2, ZnO, Li.sub.2 O, Na.sub.2 O, K.sub.2 O, MnO.sub.2, and BO.sub.3/2.
It is also found that an addition of suitable amount of Al.sub.2 O.sub.3 together with Nb.sub.2 O.sub.5 to a like glass composition is particularly advantageous to make the devitrification temperature sufficiently lower than the spinning temperature of 10.sup.2.5 poise viscosity. In fact, the addition of Al.sub.2 O.sub.3 will substantially restrains the precipitation of cristobalite structure of SiO.sub.2 crystals while the addition of Nb.sub.2 O.sub.5 will do the precipitation of crystals including BaO--TiO--ZrO.sub.2, thereby effectively lowering the devitrification temperature in relation to the spinning temperature of 10.sup.2.5 poise viscosity.
The glass composition thus incorporating Al.sub.2 O.sub.3 together with Nb.sub.2 O.sub.5 consists essentially of:
5 to 25 mol % of at least one selected from the group consisting of TiO.sub.2 and ZrO.sub.2 ;
0.5 to 15 mol % of NbO.sub.5/2 as calculated from an incorporated amount of Nb.sub.2 O.sub.5 ; and 0.5 to 15 mol % of AlO.sub.3/2 as calculated from an incorporated amount of Al.sub.2 O.sub.3.
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.r ] of 9 or more at 1 MHz and 25 devitrification temperature which is remarkably lower than a spinning temperature at which said composition exhibits a viscosity of 10.sup.2.5 poise.
Al.sub.2 O.sub.3 acts in combination with SiO.sub.2 as a glass network former and at the same time acts to lower the devitrification temperature and raise the viscosity of the melted composition. No substantial effect is seen when added in less than 0.5 mol % and the devitrification temperature will adversely increase when added in more than 15 mol %. Therefore, the proportion of Al.sub.2 O.sub.3 should be limited to be within a range of 0.5 to 15 mol %, preferably, 1 to 10 mol %.
Preferably, the glass composition additionally including Al.sub.2 O.sub.3 is composed of 46 to 60 mol % of SiO.sub.2 ; 25 to 40 mol % of at least one selected from the group consisting of CaO, SrO and BaO; 7 to 24 mol % of at least one selected from the group consisting of TiO.sub.2 and ZrO.sub.2 ; 1 to 10 mol % of NbO.sub.5/2 ; and 1 to 10 mol % of AlO.sub.3/2. With this addition of Al.sub.2 O.sub.3 together with Nb.sub.2 O.sub.5, the glass composition can be made to have a devitrification temperature which is sufficiently lower than the 10.sup.2.5 poise temperature by as much as 90
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 dielectric 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 m.sup.2 /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 m.sup.2 /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 m.sup.2 /g specific surface area, the particles will lower moisture proof (water proof) property and degrade dielectric loss tangent (tan δ). Below 0.2 m.sup.2 /g specific surface area, the particles are not expected to increase 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 BaTiO.sub.3, SrTiO.sub.3, PbTi.sub.1/2 Zr.sub.1/2 O.sub.3, Pb(Mg.sub.2/3 Nb.sub.1/3)O.sub.3, Ba(Sn.sub.x Mg.sub.y Ta.sub.z)O.sub.3, and Ba(Zr.sub.x Zn.sub.y Ta.sub.z)O.sub.3. Besides, the porous inorganic dielectric particle may be oxides or complex oxides of TiO.sub.2, ZrO.sub.2, and SnO.sub.2. 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.r ] 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--SiO.sub.2 --B.sub.2 O.sub.3, CaO--SiO.sub.2 --B.sub.2 O.sub.3, Li.sub.2 O--SiO.sub.2 --B.sub.2 O.sub.3, Li.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2, Na.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2, Li.sub.2 O--GeO.sub.2, CdO--PbO--SiO.sub.2, Li.sub.2 O--SiO.sub.2, B.sub.2 O.sub.3 --Bi.sub.2 O.sub.3, PbO--SiO.sub.2 --BaO, Na.sub.2 O--PbO--SiO.sub.2, PbO--GeO.sub.2, CuO, Bi.sub.2 O.sub.3, B.sub.2 O.sub.3, CdO, Li.sub.2 O, PbO, WO.sub.3, Pb.sub.5 Ge.sub.3 O.sub.11, Li.sub.2 SiO.sub.3, LiF, CuF.sub.2, ZnF.sub.2, and CaF.sub.2.
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, hereby increasing the dielectric constant [ε.sub.r ] of the circuit board.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of an inorganic dielectric particles dispersed in a resin layer of a circuit board fabricated in accordance with the present invention; and
DESCRIPTION OF THE INVENTION A glass fiber forming composition in accordance with the present invention is prepared from corresponding oxide (including complex oxide) and/or carbonate, sulfate, chloride, fluoride or the like compound such that it consists essentially of:
5 to 25 mol % of at least one component selected from the group consisting of TiO.sub.2 and ZrO.sub.2 ; and
5 to 25 mol % of at least one component selected from the group consisting of TiO.sub.2 and ZrO.sub.2 ;
0.5 to 15 mol % of NbO.sub.5/2 as calculated from an incorporated amount of Nb.sub.2 O.sub.5 ; and
0.5 to 15 mol % of AlO.sub.3/2 as calculated from an incorporated amount of Al.sub.2 O.sub.3.
The porous inorganic dielectric particles to be dispersed in the resin layer of the circuit board is shown in FIG. 1 to have minute pores, voids, cracks or the like openings in the outer surface into which the resin can easily permeate, and having an average particle size of 5 to 100 μm and a specific surface area of 0.3 to 7.0 m.sup.2 /g. The dielectric particles may be obtained by pulverizing inorganic dielectric blocks which have been sintered at a relatively low temperature into porous structure. Alternately, the dielectric particles may be obtained by firstly dissipating suitable inorganic particles into, for example, a water solution of PVA (polyvinylalcohol) followed by spraying the solution in a dry atmosphere, for example, at a temperature of 130 make resulting granules, and then baking or sintering the resulting granules at a temperature of about 1100 particles. In the latter process, the sintering is carried out in such a manner as to effect physical and chemical bondings between particles within the spray-formed granules and to permit grain growth of minute particles but to leave the granules readily separable from each other. The resulting particles are found to be sufficiently porous as they have pores and cracks in the outer surface as well as internal voids.
At the sintering, a suitable additive may be employed to control grain growth and electrical characteristics of the sintered dielectric particles as usual in the general sintering process. In view of that the dielectric particles are preferred to have an average particle size of 5 to 100 μm and a specific surface area of 0.3 to 7.0 m.sup.2 /g, when forming the dielectric particles as secondary particles agglomerated from primary particles, the primary particles are required to have an average particle size of 0.1 to 5 μm, as determined from a following relation among the particle size d of the primary particle, true specific weight ρ of the primary particle, and specific surface area (Sw) of the secondary particle: ##EQU1## That is, an optimum size of the primary particles for barium titanate (BaTiO.sub.3) is determined to be 0.14 to 3.3 μm.
The metal foil may be of copper or aluminum and is pressed together with the laminate of the prepregs by a suitable pressure which is selected in order to give a desired thickness to the resulting circuit board and at the same time to avoid breaking the dielectric particles. The heating temperature for effecting the cross-linking depends primarily on the reaction temperature of the initiator and is therefore suitably selected in accordance with the kinds of the initiator included in the PPO composition. The heating time may be also selected in accordance with the kinds of the initiator. For example, the heat press is effected at a temperature of 150 kg/cm.sup.2 for 10 to 60 minutes. FIG. 2 illustrates a typical one of thus fabricated circuit board which comprises the PPO resin layer 1 reinforced by the glass cloth 2, the dielectric particles 3 dispersed in the layer 1, and the metal foils 4 on both sides of the circuit board.
GLASS COMPOSITIONS Examples 1 to 32 and Comparative Examples 1 to 3 Glass forming materials were placed in a platinum crucible and heated at 1500 listed proportion of components in Tables 1 to 6. The glass forming materials employed were SiO.sub.2, carbonates of MgO, CaO, SrO, and BaO, anatase TiO.sub.2, ZrO.sub.2, and Nb.sub.2 O.sub.5. Then, the melted glass compositions were caused to flow over a carbon-made plate and annealed to provide individual glass plates. The resulting glass plates were examined with regard to the following characteristics [A] to [D]. The results are included in Tables 1 to 6.
[A] Dielectric constant and dielectric loss tangent 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.r ] and dielectric loss tangent [tan δ] by an impedance analyzer at 25 and 1 GHz.
[B] 10.sup.2.5 poise temperature A portion of each glass plate was melted and was measured by a platinum ball lifting method as to a melt viscosity for determination of a temperature at which the melt viscosity becomes 10.sup.2.5 poise.
[C] Devitrification temperature A portion of each glass plate was pulverized into particles having a particle size of 297 to 500 μm. The particles were then placed in a platinum tray. The tray was kept within an electric furnace having a temperature gradient for 16 hours and was then allowed to cool in the air for determination of the devitrification temperature by microscope observation as to the appearance of the devitrification.
[D] Glass fiber forming feasibility The remainder of each glass was pulverized and placed into a platinum tray and melted by electrically heating the tray. While maintaining the tray at 10.sup.2.5 poise temperature, the melt was drawn or spun through a minute nozzle in the bottom of the tray and wound in order to obtain a glass fiber.
TABLE 1__________________________________________________________________________          Example 1                Example 2                      Example 3                            Example 4                                  Example 5                                        Example 6                                              Example                                                    Example__________________________________________________________________________                                                    8Composition(mol %)SiO.sub.2      50.0  50.0  50.0  50.0  50.0  50.0  50.0  50.0CaO            7.5   7.5   7.5   7.5   7.5   7.5   7.5   9.0SrO            7.5   7.5   7.5   7.5   7.5   7.5   7.5   6.0BaO            15.0  15.0  15.0  15.0  15.0  15.0  15.0  15.0MgO            --    --    --    --    --    --    --    --TiO.sub.2      9.08  10.73 11.55 10.7  12.38 13.2  14.85 11.55ZrO.sub.2      1.92  2.27  2.45  3.3   2.62  2.8   3.15  2.45NbO.sub.5/2    9.0   7.0   6.0   6.0   5.0   4.0   2.0   6.0dielectric constant &#949;.sub.&#915;  (1 MHz)          11.7  11.6  11.6  11.2  11.5  11.5  11.5  11.5dielectric constant &#949;.sub.&#915;  (1 GHz)          11.7  11.6  11.6  11.2  11.5  11.5  11.5  11.5dielectric loss tan &#948; [%]          0.08  0.08  0.09  0.09  0.08  0.08  0.09  0.08(1 MHz)dielectric loss tan &#948; [%]          0.31  0.30  0.29  0.28  0.30  0.30  0.29  0.30(1 GHz)10.sup.2.5 poise temp. Tx (          1147  1150  1153  1152  1155  1151  1158  1149devitrification temp. Ty (          1080  1071  1070  1090  1080  1095  1120  1066(Tx-Ty)            67    79    83    62    75    56    38    83glass fiber forming feasibility          good  good  good  godd  good  good  good  good__________________________________________________________________________
TABLE 2__________________________________________________________________________           Example 9                 Example 10                       Example 11                             Example 12                                   Example 13                                         Example 14                                               Example__________________________________________________________________________                                               15Composition(mol %)SiO.sub.2       52.5  52.5  55.0  55.0  55.0  49.0  49.02CaO             9.3   7.75  7.5   7.5   7.5   7.3   7.35SrO             6.2   7.75  7.5   7.5   7.5   7.3   7.35BaO             15.5  15.5  15.0  15.0  15.0  14.6  14.71MgO             --    --    --    --    --    --    --TiO.sub.2       9.53  9.53  8.7   9.28  9.9   14.5  14.56ZrO.sub.2       2.02  2.02  1.8   1.97  2.1   3.4   3.09NbO.sub.5/2     4.95  4.95  4.5   3.75  3.0   3.9   3.92dielectric constant &#949;.sub.&#915;  (1 MHz)           11.0  10.9  10.5  10.5  10.4  11.8  11.9dielectric constant &#949;.sub.&#915;  (1 GHz)           10.9  10.9  10.5  10.4  10.4  11.8  11.8dielectric loss tan &#948; [%] (1 MHz)           0.07  0.07  0.08  0.07  0.07  0.09  0.08dielectric loss tan &#948; [%] (1 GHz)           0.29  0.29  0.27  0.28  0.28  0.29  0.3010.sup.2.5 poise temp. Tx (           1164  1168  1180  1173  1175  1157  1145devitrification temp. Ty (           1096  1124  1126  1130  1117  1112  1102(Tx-Ty)             68    44    54    43    58    45    43glass fiber forming feasibility           good  good  good  good  good  good  good__________________________________________________________________________
TABLE 3______________________________________          Exam- Exam-   Exam-   Exam-          ple 16                ple 17  ple 18  ple 19______________________________________Composition(mol %)SiO.sub.2        47.16   50.0    50.0  50.0CaO              7.03    6.5     7.5   6.9SrO              7.03    6.5     7.5   6.9BaO              14.05   13.0    15.0  13.7MgO              --      4.0     --    --TiO.sub.2        13.95   14.85   11.5  11.5ZrO.sub.2        3.27    3.15    2.5   2.5NbO.sub.5/2      7.51    2.0     4.5   6.0TaO.sub.5/2      --      --      1.5   --LaO.sub.3/2      --      --      --    2.5dielectric constant &#949;.sub.&#915;  (1 MHz)            12.3    11.2    11.2  11.4dielectric constant &#949;.sub.&#915;  (1 GHz)            12.3    11.2    11.2  11.4dielectric loss tan &#948; [%]            0.08    0.10    0.07  0.09(1 MHz)Dielectric loss tan &#948; [%]            0.31    0.30    0.30  0.31(1 GHz)10.sup.2.5 poise temp. Tx (            1085    1149    1153  1145devitrification temp. Ty (            1085    1095    1090  1115(Tx-Ty)              51       54     63    30glass fiber forming feasibility            good    good    good  good______________________________________
TABLE 4______________________________________      Exam- Exam-   Exam-   Exam- Exam-      ple 20            ple 21  ple 22  ple 23                                  ple 24______________________________________Composition(mol %)SiO.sub.2    50.0    50.0    50.0  50.0  40.0CaO          6.9     6.9     6.8   7.5   9.0SrO          6.9     6.9     6.8   7.5   6.0BaO          13.7    13.7    13.4  15.0  15.0MgO          --      --      --    --    --TiO.sub.2    11.5    11.5    11.5  7.45  17.33ZrO.sub.2    2.5     2.5     2.5   1.6   3.67NbO.sub.5/2  6.0     6.0     6.0   11.0  9.0CeO.sub.2    2.5     --      --    --    --ZnO          --      2.5     --    --    --Li.sub.2 O   --      --      1.0   --    --Na.sub.2 O   --      --      1.0   --    --K.sub.2 O    --      --      1.0   --    --Dielectric constant        11.5    11.1    11.1  11.7  14.1&#949;.sub.&#915;  (1 MHz)Dielectric constant        11.5    11.1    11.1  11.6  14.1&#949;.sub. &#915;  (1 GHz)dielectric loss tan &#948;        0.08    0.09    0.05  0.08  0.11[%] (1 MHz)dielectric loss tan &#948;        0.30    0.30    0.22  0.30  0.31[%] (1 GHz)10.sup.2.5 poise temp. Tx        1145    1136    1080  1142  1090(devitrification temp.        1118    1130    1078  1140  1089Ty ((Tx-Ty)          27       6       2     2     1glass fiber forming        good    good    good  good  goodfeasibility______________________________________
TABLE 5__________________________________________________________________________          Example 25                Example 26                      Example 27                            Example 28                                  Example 29                                        Example 30                                              Example                                                    Example__________________________________________________________________________                                                    32Composition(mol %)SiO.sub.2      55.0  50.0  50.0  50.0  50.0  50.0  48.0  50.0CaO            9.0   9.0   9.0   7.5   9.0   6.8   9.0   6.9SrO            6.0   6.0   6.0   7.5   6.0   6.8   6.0   6.9BaO            15.0  15.0  15.0  15.0  15.0  13.4  15.0  13.7TiO.sub.2      7.8   9.9   9.5   9.5   9.1   11.5  9.1   11.5ZrO.sub.2      1.7   2.1   2.0   2.0   1.9   2.5   1.9   2.5NbO.sub.5/2    3.0   6.0   6.0   6.0   6.0   6.0   6.0   6.0AlO.sub.3/2    2.5   2.0   2.5   2.5   3.0   3.0   5.0   2.5dielectric constant &#949;.sub.&#915;  (1 MHz)          10.1  11.2  11.1  11.1  11.0  11.0  11.0  11.0dielectric constant &#949;.sub.&#915;  (1 GHz)          10.1  11.2  11.1  11.1  11.0  11.0  11.0  11.0dielectric loss tan &#948; [%]          0.07  0.08  0.08  0.08  0.08  0.08  0.08  0.09(1 MHz)dielectric loss tan &#948; [%]          0.27  0.29  0.29  0.29  0.28  0.28  0.28  0.28(1 GHz)10.sup.2.5  poise temp. Tx (          1199  1154  1162  1160  1166  1164  1160  1158devitrification temp. Ty (          1085  1054  1063  1065  1060  1064  1057  1070(Tx-Ty)            114   100   99    95    106   100   103   88glass fiber forming feasibility          excellent                excellent                      excellent                            excellent                                  excellent                                        excellent                                              excellent                                                    excellent__________________________________________________________________________
TABLE 6______________________________________     Comparative              Comparative                         Comparative     Example 1              Example 2  Example 3______________________________________Composition(mol %)SiO.sub.2   40.0       50.0       50.0CaO         7.5        7.5        9.0SrO         7.5        7.5        6.0BaO         15.0       15.0       15.0MgO         --         --         11.5TiO.sub.2   23.0       16.5       2.5ZrO.sub.2   7.0        3.5        --NbO.sub.5/2 --         --         --AlO.sub.3/2 --         --         6.0dielectric constant       13.5       11.0       10.6&#949;.sub.&#915;  (1 MHz)dielectric constant       13.5       11.0       10.6&#949;.sub.&#915;  (1 GHz)dielectric loss tan       0.13       0.09       0.09&#948; [%] (1 MHz)dielectric loss tan       0.32       0.29       0.30&#948; [%] (1 GHz)10.sup.2.5 poise temp.       1077       1147       1176Tx (devitrification temp.       1214       1204       1203Ty ((Tx-Ty)        -137       -57        -27glass fiber forming       not        not        notfeasibility acceptable acceptable 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 Nb.sub.2 O.sub.5 and incorporating excess amounts of TiO.sub.2 and ZrO.sub.2, Comparative Example 2 lacking Nb.sub.2 O.sub.5, and Comparative Example 3 incorporating Al.sub.2 O.sub.3 but not Nb.sub.2 O.sub.5. For all of Comparative Examples 1 to 3, the devitrification temperature Ty is higher than the 10.sup.2.5 poise temperature Tx in contrast to Examples 1 to 32. Thus, the relation [Tx - Ty] between the devitrification temperature and 10.sup.2.5 poise temperature is found to well indicative of the glass fiber forming feasibility. Also, it is confirmed that Al.sub.2 O.sub.3 alone will not impart the glass fiber forming feasibility.
CIRCUIT BOARDS Example 33 A double-sided circuit board was fabricated from PPO (poly-phenylene-oxide) resin which was reinforced by a glass cloth obtained from the glass fiber of Example 3 and additionally incorporated a number of porous dielectric particles.
The glass cloth utilized was a plain weave having a thickness of 100 μm with a fiber diameter of 7 μm and having a weave density of 60 warps and 58 wefts per 25
The porous dielectric particles were chiefly composed of BaTi.sub.0.7 Zr.sub.0.3 O.sub.3, which were prepared through the steps of wet-blending 500 g of BaTi.sub.0.7 Zr.sub.0.3 O.sub.3 having an average particle size of 0.1 μm, 2.5 g of borosilicate glass (available from Iwaki Glass Co., Ltd., Japan), 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 1050 2 hours. The resulting porous dielectric particles were agglomerated or secondary particles from the primary particles and have an average particle size of 20 μm and a specific surface area of 1.0 m.sup.2 /g.
Mixture of 180 parts by weight [30 vol %] of porous BaTi.sub.0.7 Zr.sub.0.3 O.sub.3 particles and 74 parts by weight [70 vol %] of PPO were added to 300 parts by weight of trichloroethylene (sold under the trade name of "Trichlene" from Toa Gosei Chemical Industry Co., Ltd., Japan) and then stirred by means of a 2 l capacity reactor with bubble distinguishing capability to obtain a bubble-free resin varnish in which PPO was completely dissolved.
The glass cloth was impregnated in thus prepared resin varnish and dried at 50 mixture of PPO and BaTi.sub.0.7 Zr.sub.0.3 O.sub.3 particles and 38 wt % [about 30 vol %] of the glass cloth. Five sheets of the resulting prepregs were laminated together with 17 μm thick copper foils and heat-pressed at a pressure of 33 Kg/cm.sup.2 at 250 double-side circuit board.
Comparative Example 4 A double-sided circuit board was fabricated in the identical manner as in Example 33 except that a glass cloth utilized was obtained from a lead glass which consists essentially of 41.2 mol % of PbO, 55.3 mol % of SiO.sub.2, 2.8 mol % of B.sub.2 O.sub.3, and 0.7 mol % of K.sub.2 O and which has a dielectric constant of 13.0 at 1 MHz, 12.9 at 1 GHz and a dielectric loss tangent [tan δ] of 0.09 % at 1 MHz and 0.54 % at 1 GHz.
Comparative Example 5 A double-sided circuit board was fabricated in the identical manner as in Example 33 except that a glass cloth utilized was obtained from an E-glass which consists essentially of 57.9 mol % of SiO.sub.2, 8.7 mol % of Al.sub.2 O.sub.3, 7.3 mol % of B.sub.2 O.sub.3, 24.2 mol % of CaO, 1.6 mol % of MgO, and 0.3 mol % of K.sub.2 O and which has a dielectric constant of 6.5 at 1 MHz and also at 1 GHz and a dielectric loss [tan δ] of 0.15% at 1 MHz and 0.28% at 1 GHz.
Examples 34 to 39 Double-sided circuit boards were fabricated in the identical manner as in Example 33 except that there were utilized the PPO compositions of different component proportions as listed in Table 7.
TABLE 7__________________________________________________________________________         Examples(by weight parts)         34 &amp; 47              35 &amp; 48                   36 &amp; 49                        37 &amp; 50                             38 &amp; 51                                   39 &amp; 52__________________________________________________________________________PPO (poly-phenylene-oxide)         110   40  110   40  110   110cross-linking polymer         SBS.sub.#1)              SBS  SBS  SBS  p-TAIC.sub.#3)                                   --         80 parts              120 parts                   80 parts                        120 parts                             90 partscross-linking monomer         TAIC.sub.#2)              TAIC TAIC TAIC --    TAIC         10 parts               40 parts                   10 parts                         40 parts  90 partsinitiator.sub.#4)          4    4    4    4    4     4porous dielectric particles         470  470  470  470  470   470solvent (trichloroethylene)         1000 1000 1000 1000 1000  1000__________________________________________________________________________ .sub.#1) SBS is for styrene butadiene copolymer .sub.#2) TAIC for triallylisocyanate .sub.#3) pTAIC for polymer of TAIC, .sub.#4) 25-dimethyl-2-5-di-(tert-butylperoxy)hexyne-3 [sold under the tradename of Perhexyne 25B from Nippon Yushi KK
Example 40 A double-sided circuit board was fabricated in the identical manner as in Example 33 except that dielectric particles utilized were non-porous BaTi.sub.0.7 Zr.sub.0.3 O.sub.3 having an average particle size of 20 μm and a specific surface area of 0.2 m.sup.2 /g.
Example 41 A double-sided circuit board was fabricated in the identical manner as in Example 33 except that dielectric particles utilized were non-porous BaTi.sub.0.7 Zr.sub.0.3 O.sub.3 having an average particle size of 1.6 μm and a specific surface area of 1.5 m.sup.2 /g.
Example 42 A double-sided circuit board was fabricated in the identical manner as in Example 33 except that dielectric particles utilized were 347 g of non-porous TiO.sub.2 [rutile] having an average particle size of 3.4 μm and a specific surface area of 1.7 m.sup.2 /g.
Example 43 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 Ba.sub.0.7 Sr.sub.0.3 TiO.sub.3 having an average particle size of 0.1 μm, 1.7 g of CuO, and 50 ml of 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 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 m.sup.2 /g.
Example 44 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 BaTi.sub.0.7 Zr.sub.0.3 O.sub.3 having an average particle size of 0.1 μm, 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 1100 porous dielectric particles were agglomerated or secondary particles from the primary particles and have an average particle size of 80 μm and a specific surface area of 5.6 m.sup.2 /g.
Example 45 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 100 g of BaTi.sub.0.7 Zr.sub.0.3 O.sub.3 having an average particle size of 0.1 μm, 1.7 g of CuO, and 10 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 1100 2 hours. The resulting porous dielectric particles were agglomerated or secondary particles from the primary particles and have an average particle size of 6 μm and a specific surface area of 5.3 m.sup.2 /g.
Example 46 A double-sided circuit board was fabricated in the identical manner as in Example 33 except that a glass cloth was obtained from the glass composition of Example 26.
Example 47 A double-sided circuit board was fabricated in the identical manner as in Example 34 except that a glass cloth was obtained from the glass composition of Example 26.
Example 48 A double-sided circuit board was fabricated in the identical manner as in Example 35 except that a glass cloth was obtained from the glass composition of Example 26.
Example 49 A double-sided circuit board was fabricated in the identical manner as in Example 36 except that a glass cloth was obtained from the glass composition of Example 26.
Example 50 A double-sided circuit board was fabricated in the identical manner as in Example 37 except that a glass cloth was obtained from the glass composition of Example 26.
Example 51 A double-sided circuit board was fabricated in the identical manner as in Example 38 except that a glass cloth was obtained from the glass composition of Example 26.
Example 52 A double-sided circuit board was fabricated in the identical manner as in Example 39 except that a glass cloth was obtained from the glass composition of Example 26.
Example 53 A double-sided circuit board was fabricated in the identical manner as in Example 40 except that a glass cloth was obtained from the glass composition of Example 26.
Example 54 A double-sided circuit board was fabricated in the identical manner as in Example 41 except that a glass cloth was obtained from the glass composition of Example 26.
Example 55 A double-sided circuit board was fabricated in the identical manner as in Example 42 except that a glass cloth was obtained from the glass composition of Example 26.
Example 56 A double-sided circuit board was fabricated in the identical manner as in Example 43 except that a glass cloth was obtained from the glass composition of Example 26.
Example 57 A double-sided circuit board was fabricated in the identical manner as in Example 44 except that a glass cloth was obtained from the glass composition of Example 26.
Example 58 A double-sided circuit board was fabricated in the identical manner as in Example 45 except that a glass cloth was obtained from the glass composition of Example 26.
The circuit boards of Examples 33 to 58 and Comparative Examples 4 and 5 were examined with regard to dielectric constant [ε.sub.r ], dielectric loss tangent [tan δ], peel strength, solder resistance at 260 resistance, the circuit boards of the Examples and the comparative Examples were cut into 30 same kind were floated on a melted solder maintaining at 260 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 means that the specimen sees no substantial deformation even after being exposed to the solder of 260
TABLE 8__________________________________________________________________________       dielectric constant                 dielectric loss solder resistance       &#949;.sub.&#915;                 tan &#948; (%)                          peel strength                                 at 260       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__________________________________________________________________________
Another test was made by the use of PCT tester (manufactured by Shimadzu Seisakusho, Ltd.) with regard to grain strength of the porous dielectric particles utilized in Examples 33 to 39, 43, 45 to 52, 56, and 58 which were obtained by sintering in the presence of the sintering aid of borosilicate glass and those utilized in Examples 44 and 57 which were obtained by sintering in the absence of the sintering aids. The results are that the porous dielectric particles of the former Examples [33 to 39, 43, 45 to 52, and 58] has a grain strength of 7.0 to 8.5 kg/mm.sup.2, while those of the latter Examples [44 and 57] has a grain strength of 3.5 to 3.8 kg/mm.sup.2. Accordingly, it is also confirmed that the use of the sintering aid in forming the porous dielectric particles is particularly advantageous for increasing the grain strength.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS3060041 *Jan 20, 1960Oct 23, 1962Microcell LtdGlass compositionsUS4055435 *Jun 2, 1976Oct 25, 1977Hoya Glass Works, Ltd.Glass compositions for ophthalmic lensesUS4179300 *Jan 20, 1978Dec 18, 1979Hoya CorporationOptical glassUS4390638 *Jul 13, 1981Jun 28, 1983Schott GlaswerkeAcidproof, hydrolysis-resistant optical and ophthalmic glass of low densityUS4400473 *Jun 2, 1982Aug 23, 1983Schott GlaswerkeAcidproof, hydrolysis-resistant optical and ophathalmic glass of low densityUS4830989 *Feb 22, 1988May 16, 1989Pfizer Inc.Alkali-resistant glass fiberEP0013379A1 *Dec 17, 1979Jul 23, 1980Rogers CorporationDielectric material, circuit boards made from this material, and method of making said material and said circuit boardsEP0227269A1 *Nov 4, 1986Jul 1, 1987Corning Glass WorksOptical and ophthalmic glassesFR1561647A * Title not availableGB2172892A * Title not availableJPH0250834A * Title not availableJPH01179741A * Title not available* Cited by examinerNon-Patent CitationsReference1 *Patent Abstracts of Japan, vol. 13, No. 461 (C 645) 18 Oct. 1989 & JP A 01 179 741, Jul. 17, 1989.2Patent Abstracts of Japan, vol. 13, No. 461 (C-645) 18 Oct. 1989 & JP-A-01 179 741, Jul. 17, 1989.3 *World Patents Index Latest, Week 03, Derwent Publications Ltd., AN 90 096954 & JP A 2 050 834, Feb. 20, 1990.4World Patents Index Latest, Week 03, Derwent Publications Ltd., AN 90-096954 & JP-A-2 050 834, Feb. 20, 1990.* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS5674616 *Feb 6, 1995Oct 7, 1997Conversion Technologies International, Inc.Glass beads having improved fracture toughnessUS5874375 *Oct 29, 1996Feb 23, 1999Unifrax CorporationHigh temperature resistant glass fiberUS5932347 *Dec 31, 1996Aug 3, 1999Owens Corning Fiberglas Technology, Inc.Mineral fiber compositionsUS6025288 *Jan 13, 1999Feb 15, 2000Unifrax CorporationHigh temperature resistant glass fiberUS6030910 *Aug 13, 1998Feb 29, 2000Unifrax CorporationHigh temperature resistant glass fiberUS6309990 *Oct 8, 1997Oct 30, 2001Nitto Boseki Co., Ltd.Glass fiber of low permittivityUS6358871Mar 22, 2000Mar 19, 2002Evanite Fiber CorporationLow-boron glass fibers and glass compositions for making the sameUS6419981Jul 20, 2000Jul 16, 2002Ppg Industries Ohio, Inc.Impregnated glass fiber strands and products including the sameUS6593255Nov 3, 2000Jul 15, 2003Ppg Industries Ohio, Inc.Impregnated glass fiber strands and products including the sameUS6794322Dec 5, 2001Sep 21, 2004Evanite Fiber CorporationLow-boron glass fibers and glass compositions for making the sameUS6878651Dec 1, 2000Apr 12, 2005Ford Global Technologies, LlcGlass compositions for ceramic electrolyte electrochemical conversion devicesUS6949289Nov 3, 2000Sep 27, 2005Ppg Industries Ohio, Inc.Impregnated glass fiber strands and products including the sameUS6953757Jan 10, 2003Oct 11, 2005Unifrax CorporationHigh temperature a resistant vitreous inorganic fiberUS7007509Mar 4, 2005Mar 7, 2006Ford Global Technologies, LlcMethod of making glass compositions for ceramic electrolyte electrochemical conversion assemblies and assemblies made therebyUS7008892 *Jul 11, 2003Mar 7, 2006AlcatelRaman-active optical fiberUS7153796Jan 19, 2005Dec 26, 2006The Morgan Crucible Company PlcSaline soluble inorganic fibresUS7155820Oct 27, 2003Jan 2, 2007Matsushita Electric Industrial Co., Ltd.Method for manufacturing printed circuit boardUS7259118Apr 28, 2004Aug 21, 2007The Morgan Crucible Company PlcSaline soluble inorganic fibersUS7354641Oct 12, 2004Apr 8, 2008Ppg Industries Ohio, Inc.Resin compatible yarn binder and uses thereofUS7468336Jun 25, 2004Dec 23, 2008Unifrax LlcHigh temperature resistant vitreous inorganic fiberUS7468337Jun 25, 2004Dec 23, 2008Unifrax I LlcHigh temperature resistant vitreous inorganic fiberUS7470641Jan 2, 2003Dec 30, 2008The Morgan Crucible Company PlcSaline soluble inorganic fibresUS7629279 *Oct 15, 2003Dec 8, 2009Nippon Electric Glass Co., Ltd.Glass fiberUS7678721Oct 26, 2006Mar 16, 2010Agy Holding Corp.Low dielectric glass fiberUS7875566Oct 31, 2005Jan 25, 2011The Morgan Crucible Company PlcModification of alkaline earth silicate fibresUS8062746Mar 10, 2003Nov 22, 2011Ppg Industries, Inc.Resin compatible yarn binder and uses thereofUS8105690Feb 11, 2004Jan 31, 2012Ppg Industries Ohio, IncFiber product coated with particles to adjust the friction of the coating and the interfilament bondingUS20120329912 *Sep 8, 2011Dec 27, 2012Taiwan Union Technology CorporationFused filler and its manufacturing method and useCN100488906COct 8, 1999May 20, 2009Ppg工业俄亥俄公司Glass fiber-reinforced prepreg, laminates, electronic circuit boards and methods for assembling fabricWO1997016386A1 *Oct 29, 1996May 9, 1997Unifrax CorpHigh temperature resistant glass fiberWO2000021900A1 *Oct 8, 1999Apr 20, 2000Lammon Hilinski KamiGlass fiber-reinforced prepregs, laminates, electronic circuit boards and methods for assembling a fabric* Cited by examinerClassifications U.S. Classification501/35, 501/70, 501/72, 501/38International ClassificationC03C13/00, H05K1/03Cooperative ClassificationC03C3/097, H05K2201/0116, C03C3/091, H05K1/0373, H05K1/0366, H05K2201/0209, C03C13/00, C03C3/102, H05K1/0326European ClassificationC03C3/097, C03C3/091, C03C3/102, H05K1/03C4D, H05K1/03C2B, C03C13/00, H05K1/03C4CLegal EventsDateCodeEventDescriptionJan 28, 2009ASAssignmentOwner name: PANASONIC ELECTRIC WORKS CO., LTD., JAPANFree format text: CHANGE OF NAME;ASSIGNOR:MATSUSHITA ELECTRIC WORKS, LTD.;REEL/FRAME:022288/0703Effective date: 20081001Jul 13, 2005FPAYFee paymentYear of fee payment: 12Jul 19, 2001FPAYFee paymentYear of fee payment: 8Jul 24, 1997FPAYFee paymentYear of fee payment: 4Feb 7, 1992ASAssignmentOwner name: MATSUSHITA ELECTRIC WORKS, LTD., JAPANOwner name: NIPPON ELECTRIC GLASS CO., LTD., JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:KOMORI, KIYOTAKA;YAMAKAWA, SEISHIRO;YAMAMOTO, SHIGERU;AND OTHERS;REEL/FRAME:006020/0255Effective date: 19920129RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google