JPH0249219B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a laminate formed by laminating a plurality of glass fabrics using a thermosetting resin as a binder. In particular, the present invention relates to a laminate having glass fabric as a reinforcing base material, which has excellent cold punching workability. Conventionally, glass fabric has been mainly used as a reinforcing base material for electrical insulating boards or copper-clad laminates for printed circuits used in electronic devices, telecommunications equipment, etc. that require extremely high quality. Glass fabric-based laminates have the most required dimensional stability, mechanical strength, electrical properties, heat resistance, and
This is because it has excellent properties such as chemical resistance. However, laminates made of glass fabric as a base material have the disadvantage that cold punching is difficult and machinability such as drilling is extremely poor. On the other hand, laminates using glass fabric, glass paper, glass strand mat, glass fiber, etc. as the base material are also widely known. These substrates have a weak reinforcing effect in the planar direction compared to glass fabric substrates, so although they are superior in laminate machining methods, especially cold punching, on the other hand, they are given top priority. Properties such as dimensional stability, mechanical strength, electrical properties, and chemical resistance are considerably inferior to those of glass fabric substrates. Furthermore, laminates using glass non-woven cloths containing inorganic fillers, glass paper, etc. as base materials have been proposed for the purpose of improving mechanical strength and other properties. Although this laminate is said to have excellent cold punching properties, and slight improvements in mechanical strength and electrical properties are observed, properties such as dimensional stability and heat resistance are still unsatisfactory. In addition, so-called composite-type laminates have been devised in which glass fabric is used as the base material for both surface layers of the laminate, and non-woven glass cloth containing inorganic fillers, glass paper, etc. are used as the base material for the intermediate layer. Ta. Although these laminates have excellent cold punching properties and have considerable performance in terms of mechanical strength, electrical properties, and heat resistance, their properties other than cold punching properties are inferior to that of glass. At present, it is nowhere near as good as laminates based on textiles. In particular, these laminates have poor dimensional stability not only in the planar direction but also in the Z-axis direction, resulting in fatal defects such as warpage, twisting, and breakage of through-hole plating. Furthermore, it is difficult to say that heat resistance, chemical resistance, etc. are also satisfactory. The present inventors have developed properties such as dimensional stability, mechanical strength, electrical properties, heat resistance, and chemical resistance that are almost comparable to conventional laminates using only glass fabric as a base material. As a result of intensive research to develop a glass fabric-reinforced laminate with excellent cold punching properties, we succeeded in achieving the above-mentioned properties by suppressing the strength of the threads that make up the base glass fabric. I have found that my purpose can be achieved. This glass fabric reinforced laminate is a laminate made by laminating and molding a plurality of glass fabrics using a thermosetting resin as a binder, and the tensile strength of the glass threads constituting the glass fabric is less than 10 gf/tex for both warp and weft. and the sum of both is less than 15 gf/tex, and the applicant filed the patent application on the same date as the present patent application. The laminate according to the above-mentioned patent application has excellent cold punching workability and maintains satisfactory levels of dimensional stability, heat resistance, and other properties. However, in terms of mechanical strength, especially bending strength, G-10 and FR-4 (both US
Slightly inferior to the HEMA standard). The purpose of the present invention is to provide a laminated sheet containing glass fabric that is comparable in mechanical strength including bending strength to ordinary G-10 and FR-4 and has excellent cold punching workability. It is in. The glass fabric-containing laminate according to the present invention is a laminate formed by laminating and molding a plurality of glass fabrics using a thermosetting resin as a binder, and A. The tensile strength of the glass threads constituting the glass fabric is 10 gf for both warp and weft. B. At least one glass fabric whose tensile strength is less than 10 gf/tex for both the warp and weft, and the sum of both is less than 15 gf/tex. Both are characterized by being made of one layer. In the present invention, "the tensile strength of the glass threads constituting the glass fabric" refers to the tensile strength of the glass threads constituting the glass fabric immediately before lamination molding using a thermosetting resin as a binder. In other words, in general, glass fabrics are made by interweaving warp and weft yarns, but glass fabrics have a binder (sizing agent) attached to them that is used as a binding agent during spinning of raw yarns and warping of warp yarns. After weaving, the size is usually removed by heat cleaning or washing. In addition, desized glass fabrics are typically treated with coupling agents (e.g.,
After the surface is treated with a coupling agent such as a silane compound (a coupling agent such as a silane compound is used to strengthen the bond with the epoxy resin), it is laminated and molded. In the present invention, the tensile strength of the glass threads refers to the tensile strength of the glass threads constituting the glass fabric immediately before being laminated and formed after such standard pretreatment. Point. Generally, the tensile strength of glass threads constituting ordinary glass fabrics is about 10 to 14 gf/tex for both warp and weft after desizing treatment, and further,
After surface treatment with a coupling agent, that is, immediately before use for lamination molding, it is about 16 to 20 gf/tex. At least one of the glass fabrics that is the base material of the laminate of the present invention is such that the tensile strength of the glass threads constituting it is lower than that of the warp and weft immediately before being supplied to the laminate molding using a thermosetting resin as a binder.
less than 10gf/tex and the sum of both is 15gf/tex
tex, which is considerably lower than that of conventional glass fabric substrates. Although the tensile strength of the yarns in at least one layer of the glass fabric substrate of the present invention is considerably lower than that of the yarns of the conventional glass fabric substrate, the glass fabric substrate laminate of the present invention is It has properties such as dimensional stability, mechanical strength, electrical properties, heat resistance, and chemical resistance that are comparable to those of conventional glass fabric-based laminates, and compared to conventional glass fabric-based laminates. It is surprising that this material exhibits far superior cold punching workability. Thermosetting resins used as binders in the present invention include epoxy resins, polyimide resins, phenolic resins, polyester resins, silicone resins, polyurethane resins, and polyvinyl butyral, which are conventionally used in the production of laminates based on glass fabrics. Although resins and the like can be used, the material is not limited to these materials. Additionally, inorganic fillers and other commonly used additives can be blended with the thermosetting resin. As long as the yarn used in the glass fabric used as the base material in the present invention is a long glass fiber, there are no restrictions on the single yarn diameter, number of converged yarns, etc. Furthermore, there are no particular restrictions on the composition of the glass, but E glass with a low alkali content and D glass with a low dielectric constant are generally advantageously used as glasses for electrical insulating boards or printed circuit boards. Glass fabrics are usually made of warp and weft interwoven, and weave structures include plain weave, twill weave, satin weave, etc., but the structure of the glass fabric used in the present invention is not particularly limited. Glass fabrics have a binder (sizing agent) mainly composed of starch, polyvinyl alcohol, etc. used as a binding agent during yarn spinning and warping, but they are usually processed by heat cleaning, washing, etc. after weaving. Deglue with. Furthermore, after de-sizing, the surface is treated with a coupling agent such as a silane compound to form a base material for a laminate. The coupling agent exerts a crosslinking effect between the glass and the resin binder,
Increase the bond between the two. A suitable coupling agent is selected to match the resin binder used.
For example, compatible coupling agents for epoxy resin binders can be selected from among silane compounds. As mentioned above, the glass threads in at least one layer of the base material layers constituting the glass fabric base material laminate of the present invention are characterized by extremely low tensile strength,
Its tensile strength is much lower than that of glass as defined in JIS R 3413-3.2(3). Generally, the tensile strength of glass thread is determined by the amount of adhesive applied,
Although the amount of coupling agent deposited and the temperature of heat cleaning vary depending on time, a special strength-lowering treatment is required to obtain a low-strength glass fabric as used in the present invention. Other methods of reducing strength include heat cleaning at a high temperature of 400°C or higher for a relatively long period of time, or immersion in an acid or alkali solution, but the former method requires a long period of time in a special furnace. The latter method is not very advantageous from an industrial perspective because of its processing, and the latter method has the problem of adversely affecting the electrical properties of the glass fabric base laminate finally obtained. A particularly preferred strength-lowering treatment method is to apply a dilute solution of a specific silane compound such as tetraalkoxysilane, trialkoxysilane, or dialkoxysilane to the glass fabric, and then remove the glass fabric with a trace amount of the silane compound attached. This is a heating method. By such a method, it is possible to reduce the strength very effectively and industrially. It is desirable that the specific silane compound described above be applied prior to heat cleaning to remove the sizing agent. This application can be accomplished by dipping the glass fabric in a dilute solution of the silane compound or by spraying the glass fabric with a dilute solution. The amount of the silane compound applied and the heat cleaning heating temperature as described above have a positive correlation with the amount of decrease in the tensile strength of the glass thread.
By changing the application amount and heat cleaning heating temperature, the tensile strength of the glass thread can be arbitrarily controlled. Note that the lower limit of the tensile strength of the glass threads constituting the low-strength glass fabric as described above is such that the dimensional stability, mechanical strength, and other properties of the resulting laminate and compatibility in the laminate molding process are satisfied. There is no particular limitation as long as the tensile strength of the warp is approximately 5g.
It is desirable that it is f/tex or more. The laminate according to the present invention includes at least one sheet of the above-mentioned low-strength glass fabric, and the tensile strength of the glass threads constituting the glass fabric is 10 g for both warp and weft.
At least one of the conventional glass fabrics (hereinafter referred to as "high-strength glass fabrics") having a f/tex or higher
It is made by laminating and molding the sheets. The number of laminated glass fabrics constituting the base material of the laminate is not particularly limited, and varies depending on the use of the laminate. Generally, a laminated structure in which at least three glass fabrics are laminated and a high-strength glass fabric is disposed on at least one surface layer side is preferred.
In particular, a laminated structure in which one high-strength glass fabric is placed on each surface is best. Rotation of the laminate can be carried out according to conventional methods. That is, generally, semi-cured prepregs made by impregnating glass fabric with a resin are stacked on top of each other, and compression and heating molding is performed. Further, a casting method and a low pressure heating method are also possible. For printed circuit boards, a metal film such as copper foil is attached to one or both sides of the laminate, but a method such as an additive method in which the circuit forming material is attached after molding is also possible. Examples and comparative examples of glasses will be specifically described below. In the examples, "parts" mean parts by weight. Example 1 A glass fabric was woven in which the warp and weft were made of ECG75 1/0 (67.5 tex) and the density was 44 warp/25 mm and 32 weft 25 mm. The tensile strength of this glass fabric is 110Kgf/25 for the warp.
mm, and the weft was 80Kgf/25mm. This glass fabric was processed using the following two methods. That is, (A) Heat cleaning was performed in a heating furnace at 400° C. for 20 hours. (B) The glass fabric obtained by the method of (A) was immersed in an aqueous solution of 5 c.c. of tetraethoxysilane, squeezed, dried, and heat-cleaned again in a heating furnace at 400° C. for 20 hours. The glass fabrics obtained in (A) and (B) were then immersed in an aqueous solution containing 5 g of epoxysilane and dried. The tensile strength of the epoxy silane treated fabric (A) is 50Kgf/warp
25mm, weft 40Kgf/25mm, warp per tex
16.9gf/tex, weft 18.5gf/tex, and that of (B) is warp 22.3Kgf/25mm, weft 15.1Kgf/25mm
So, per tex, warp 7.5gf/tex weft 7.0gf/
It is tex. These glass fabrics were impregnated with an epoxy resin varnish having the following composition, and heated and dried at 160°C to prepare prepregs. Next, a total of two prepregs made of the woven fabric of (A) are placed on top and bottom surfaces, and six prepregs made of the woven fabric of (B) are sandwiched in the middle. °C, 40Kg/
^Compression molding was performed to obtain a copper-clad laminate with a thickness of 1.6 mm. Resin varnish composition AER-711 (epoxy resin manufactured by Asahi Kasei) 100 parts dicyandiamide 3 parts benzyldimethylamine 0.2 parts dimethylformamide 20 parts methyl ethyl ketone 100 parts The properties of the obtained laminate are as shown in Table 1,
It has very good punching properties, solder heat resistance, chemical resistance, coefficient of linear expansion in the thickness direction, etc., and its bending strength is on the same level as general glass fabric reinforced laminates. Example 2 The same glass fabric as in Example 1 was processed in two additional ways. That is, (C) the adhering adhesive was partially burnt out by exposing it to a high-temperature furnace at 625°C for 6 seconds, and then heat-cleaned it in a heating furnace at 400°C for 20 hours, and then 5 g/
It was immersed in an aqueous epoxy silane solution and dried. (D) A glass fabric was prepared by exposing it to a high-temperature oven at 625°C for 6 seconds to partially burn out the adhering adhesive, and immersed it in an aqueous solution of 10 g of tetraethoxysilane, squeezed the liquid, and dried it. Next, after heat cleaning this in a heating furnace at 400℃ for 20 hours,
It was immersed in an aqueous solution of epoxy silane of 100 g/g and dried. The tensile strength of the glass fabric obtained by method (C) is 48Kgf/25mm for the warp and 38Kgf/25mm for the weft.
At hit, warp 16.1gf/tex, weft 17.6gf/tex
The tensile strength of the glass fabric obtained by method (D) is 29.5 Kgf/25 mm for the warp and 9.7 Kgf/25 mm for the weft.
Warp 9.7gf/tex Weft 5.0gf/tex
It was hot. Next, one prepreg made of the woven fabric of (C) was placed on both the upper and lower surfaces, and six prepregs made of the woven fabric of (D) were sandwiched in the middle to form a copper-clad laminate in the same manner as in Example 1. Obtained. Example 3 A glass fabric was woven in which the warp and weft were made of ECG37-1/0 (135 tex) and the density was 25 threads/25 mm in both warp and weft. The tensile strength of the glass fabric was 125 Kgf/25 mm for the warp and 110 Kgf/25 mm for the weft. When this was processed using the same method as 2 (D), the tensile strength was 30.5Kgf/25mm for the warp and 30.5Kgf/25mm for the weft.
17.8Kgf/25mm, warp is 9.0gf/tex
tex and weft were 5.3gf/tex. Next, one prepreg made of the glass fabric obtained in (C) of Example 2 was stacked on each of the upper and lower surfaces, and four prepregs made of the glass fabric obtained in this example were sandwiched in the middle. A copper-clad laminate was obtained in the same manner as in Example 1. Comparative Example 1 A glass fabric was woven whose warp and weft were made of ECG75 1/0 (67.5 tex) and whose density was 44 warps/25 mm and weft 32 threads/25 mm. The tensile strength of this glass fabric is 110Kgf/25mm for warp and 80Kgf/25mm for weft.
It was hot. Next, this fabric was placed in a heating oven at 400℃ for 20 minutes.
Heat cleaning was performed for a period of time to burn off the adhering adhesive.
Next, this glass fabric was coated with tetraethoxysilane 5
It was immersed in an aqueous solution of cc/. After squeezing and drying, this glass fabric was heat-cleaned again in a heating furnace at 400°C for 20 hours, and then immersed in an aqueous solution of 5 g of epoxy silane as a coupling agent.
Dry. The tensile strength of the glass fabric treated in this way is 22.3Kgf/25mm for the warp and 15.1Kgf/25mm for the weft.
mm, warp 7.5gf/tex weft 7.0g per tex
It was f/tex. This glass fabric was impregnated with the epoxy resin varnish of Example 1 and dried by heating at 160°C to produce a prepreg. 8 sheets of prepreg and the surface
A 1.6 mm thick copper clad laminate was obtained by stacking 35 μm copper foil and compression molding at 175° C. and 40 Kg/cm ² . Comparative Example 2 In Comparative Example 1, the sample was first heated in a heating furnace at 400°C.
The glass fabric heat-cleaned for 20 hours was immediately immersed in an aqueous solution containing 5 g of epoxy silane and dried to obtain a surface-treated glass fabric. The tensile strength of this glass fabric is 50Kgf/25mm for warp and 25mm for weft.
40Kgf/25mm, warp 16.9gf/tex
The weft was 18.5 gf/tex. Next, Example 1
A copper-clad laminate was obtained in the same manner as above. Comparative Example 3 Wet-made glass paper with a basis weight of 70 g/m ² and a single fiber diameter of 9 μ was impregnated with the resin varnish of Example 1.
It was dried to create a prepreg. This prepreg
Layer 10 sheets and 35μ copper foil on the surface and heat at 175℃ for 40 minutes.
A copper-clad laminate with a thickness of 1.6 mm was obtained by compression molding at Kg/cm ² . Comparative Example 4 Eight sheets of prepreg from Comparative Example 3 were stacked on the middle layer, two sheets of prepreg from Comparative Example 2 were stacked on the upper and lower surface layers, and
A 1.6 mm thick copper clad laminate was obtained by layering 35 μm copper foil and compression molding at 175° C. and 40 Kg/cm ² . The properties of the glass fabrics and the resulting laminates used in each of the Examples and Comparative Examples are shown in Table 1 below.

[Table] Solder heat resistance Abnormal after 4 hours of boiling
Same left Same left Same left
Same as left Blisters Blisters occur
(260℃ solder bath for 20 seconds after boiling)

occurrence
immersion test)


Insulation resistance 6.2×10 ¹²
4.8×10 ¹² 9.1×10 ¹¹ 5.5
× 5.2× 3.9× 4.1×10 ¹¹
(C-96/20/65+D-2/100)
10 ¹²
10 ¹² 10 ⁹
Linear expansion coefficient in thickness direction 2.6×10 ⁻⁵
2.4×10 ⁻⁵ 8.2×10 ⁻⁵ 2
×10 ⁻⁵ 2.2× 1.2× 10 ⁻⁴
(20℃～80℃；cm/cm/deg)

10 ^-5 10 ^-4
chemical resistance


(260℃ after immersion in methylene chloride) No abnormality
No abnormality No abnormality No abnormality 〃 Blistering Slightly blistering (soaked in bath)

frequent occurrence

Claims (1)

[Scope of Claims] 1. A laminate formed by laminating and molding a plurality of glass fabrics using a thermosetting resin as a binder, A. The tensile strength of the glass threads constituting the glass fabrics is 10 gf/tex or more for both warp and weft. At least one glass fabric and at least one glass fabric in which the tensile strength of the glass threads constituting the glass fabric are less than 10 gf/tex for both warp and weft, and the sum of both is less than 15 gf/tex. A laminated board containing glass fabric that is characterized by the fact that it becomes 2. A patent for a laminate made by stacking at least three glass fabrics, in which a glass fabric whose tensile strength is 10 gf/tex or more for both warp and weft is arranged on at least one surface layer side. A laminate according to claim 1. 3 The tensile strength of glass threads for both warp and weft
3. The laminate according to claim 2, wherein glass fabric having a density of 10 gf/tex or more is disposed on both surface layers. 4. A glass fabric-containing laminate according to any one of claims 1 to 3, wherein a metal film is formed on at least one surface.