JPH05416A - Prepreg manufacturing method - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the affinity of the fiber base material for prepreg with the resin. [Structure] The fiber base material is irradiated with ultraviolet rays and then impregnated with a resin. Wavelength of ultraviolet rays 200 to 400 nm, the cumulative dose in the range of ^{100mJ / cm 2 ~2000mJ / cm 2} . Ultraviolet irradiation and treatment with a coupling agent may be used in combination.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a prepreg.

[0002]

2. Description of the Related Art The signal transmission speed and transmission loss of a circuit are greatly affected by the dielectric constant and dielectric loss tangent of a substrate. The smaller the dielectric constant of the substrate, the higher the signal transmission speed, and the smaller the dielectric loss tangent, the smaller the transmission loss. Substrates for applications requiring high signal transmission speed and high efficiency, such as computers, are required to have a low dielectric loss tangent and a low dielectric constant.

Since the heat-resistant organic fiber has a smaller dielectric constant and dielectric loss tangent than that of glass, the dielectric constant of the laminated plate having the heat-resistant organic fiber as a base material is also small. Therefore, in addition to glass fiber base materials, heat-resistant organic fiber base materials have come to be used as materials for prepregs. Examples of the heat-resistant organic fiber include aramid fiber, fluororesin fiber, and fibers such as polyetheretherketone and polyetherimide referred to as heat-resistant engineering plastics, and a yarn obtained by twisting these or alone or a glass fiber. A resin is impregnated into a woven fabric using a yarn in which the above fibers are mixed and twisted, or a non-woven fabric using these fibers, and dried to obtain a prepreg.

By the way, both glass fiber and heat-resistant organic fiber are treated with a coupling agent, a plasma treatment, a surface treatment with sodium metal, etc. individually or in combination to enhance the affinity with the resin.

[0005]

However, the treatment with the coupling agent is still inadequate, the resin is not sufficiently impregnated into the base material, and it contains voids, which deteriorates the heat resistance of the laminated plate, resulting in poor molding. Requires high pressure. For this reason, when it is used for multi-layered adhesion, the positional accuracy between layers deteriorates. Also,
When the obtained laminated plate is exposed to high temperatures, blister (interfacial peeling) and measling (peeling at the entanglement points) occur, and the dimensional stability decreases when making multiple layers, and the drill workability also bad.

The surface treatment with metallic sodium is difficult and difficult to handle. The method of plasma treatment is
Since a vacuum chamber is required and the processing method is complicated, the efficiency is low and continuous processing is difficult. An object of the present invention is to provide a simple method for improving the affinity between a base material and a resin.

[0007]

The present invention is characterized in that a fiber base material is irradiated with ultraviolet rays and then impregnated with a resin varnish and dried.

As the fiber base material, glass fiber or quartz fiber is used as the inorganic fiber. Organic fibers include aramid resin, fluororesin (tetrafluoroethylene resin, tetrafluoroethylene-hexafluoropropylene copolymer resin, tetrafluoroethylene peralkyl ether copolymer resin, etc.) Heat-resistant engineering plastic (whole aromatic) (Polyamide, polyphenylene sulfide, polyetheretherketone, polyetherimide, wholly aromatic polyester, etc.)
Is mentioned. In short, fibers that can withstand the molding temperature of the matrix resin and the melting temperature of the solder can be generally used.

Yarns obtained by mixing these inorganic or organic fibers individually or in a mixture are made into various woven fabrics such as plain weave, twill weave and satin weave,
Alternatively, it is made into a non-woven fabric and used as a base material. A mixed material of inorganic fibers and organic fibers is particularly preferable. The filament diameter of the fiber is preferably several μm to several tens μm. A yarn obtained by combining a plurality of such fibers is woven in the same manner as in ordinary woven fabric production. The thickness of this woven fabric is preferably in the range of 20 μm to 250 μm.

In the present invention, an epoxy resin, a polyimide resin, a bismaleimide-triadicine resin, a modified polyimide resin or the like can be used as the thermosetting resin, but a cyanate ester resin or a maleimide-styrilized resin having a low dielectric constant is used. Etc. are suitable.

The irradiation with ultraviolet rays may be combined with the treatment with a coupling agent. In this case, the fiber base material treated with the coupling agent may be irradiated with ultraviolet rays, or the fiber base material irradiated with ultraviolet rays may be treated with the coupling agent. It is also possible to treat the fiber base material irradiated with ultraviolet rays with a coupling agent, and then further irradiate it with ultraviolet rays.

As the coupling agent, those containing organic silane as a main component are widely used. Organosilane is
It is represented by the general formula R _n SiX _(4-n) . In this formula, R
Represents a group having at least one carbon atom, and the hydrogen atom bonded to the carbon atom may be substituted with a reactive group such as an amino group, an epoxy group, a mercapto group or a vinyl group. X is any monovalent hydrolyzable group,
For example, it represents a halogen atom, an alkoxy group or an acyloxy group, and n is an integer of 1 to 3. When n is 1 or 2, X's may be the same or different. Organosilanes may be used as a mixture of two or more kinds.

Perfluoroalkylsilanes (eg,
3,3,3-trifluoropropyltrimethoxysilane,
3,3-4,4-5,5-6,6-7,7-8,8-tridecafluorooctyltrimethoxysilane), aminosilane (for example, γ- (2-aminoethyl) aminopropyltrimethoxysilane) ), When using a coupling agent having a good affinity with the fiber base material, it is treated with the coupling agent and then irradiated with ultraviolet rays, and on the contrary, a coupling agent having a good affinity with the resin is used. In this case, it is effective to treat with a coupling agent after irradiating with ultraviolet rays.

The organic silane is usually used as an aqueous solution or a mixed solution of an organic solvent such as alcohols, ketones, glycol ethers and water and adjusted to a concentration of about 0.01 to 5% by weight. As a method of applying to the base material,
Any known method such as a dipping method, a spraying method and a gasification method can be adopted. A commonly used dipping method is to immerse a substrate in a solution at a temperature close to room temperature for a few seconds, squeeze with a mangle, and subsequently dry cure at 80 to 180 ° C. for a few minutes to obtain 0.01 to 100 parts of an organic silane. A base material provided with about 2% by weight is obtained.

The wavelength of ultraviolet rays to be irradiated is 200 to 4
A generally known processing condition is adopted by using an ultraviolet ray lamp having a wavelength of 00 nm. 10 for an ultraviolet lamp
Various lamps that emit light with a wavelength of 0 to 1000 nm (for example, a low pressure mercury lamp and a high pressure mercury lamp) can be used.

The cumulative irradiation dose is 100 mJ / cm ² to 2
The range is 000 mJ / cm ² . 100 mJ / cm ²
If it does not meet the requirements, there is no effect. The effect of UV irradiation is 20
It is saturated at 00 mJ / cm ² , and although there are differences depending on the materials, the coupling agent and the organic base material may be deteriorated by heat and deteriorated.

[0017]

[Function] The energy of ultraviolet rays makes the electronic state of the base material or the surface of the coupling agent unstable, and moisture in the air,
It is presumed that polar groups such as —OH and —COOH are formed by reacting with carbon dioxide and oxygen. Therefore, the affinity of the base material-coupling agent, the coupling agent-resin, and the base material-resin is improved, the impregnation property of the resin is improved, and voids are eliminated, so that molding at a low pressure becomes possible. It is considered that various defects that the prepreg had were eliminated.

[0018]

Example 1 100 parts by weight of a bisphenol type epoxy resin and 2.5 parts by weight of dicyandiamide were mixed, and 2-ethyl-
0.2 parts by weight of 4-methyl-imidazole and methyl ethyl ketone were added to form a varnish. The glass cloth treated with N- (β-aminoethyl) -α-aminopropyltrimethoxysilane was irradiated with ultraviolet rays by a conveyor type ultraviolet irradiation device until the cumulative irradiation amount reached 700 mJ / cm ² . The glass cloth was impregnated with the varnish and heated at 170 ° C. for 15 minutes to obtain a prepreg of 500 × 500 mm. Two sheets of this prepreg were stacked, a copper foil having a thickness of 35 μm was arranged on both sides, and heated and pressed at a temperature of 170 ° C. and a pressure of 2 MPa for 60 minutes. The obtained copper-clad laminate was etched to form an inner layer circuit board. Then, the inner layer circuit board, the prepreg and the copper foil are laminated, and the temperature is again 170 ° C. and the pressure is 2 MPa.
By heating and pressurizing for 60 minutes, a multilayer circuit board A was obtained. This multi-layer circuit board A was tested for 2 hours after the pressure cooker test.
There was no abnormality even when immersed in solder at 60 ° C for 30 seconds. No void was observed. The dimensional changes of the inner layer circuit board are 3σ = 0.007% (warp direction) and 3σ, respectively.
= 0.006% (weft direction).

For comparison, N without UV irradiation
A multilayer circuit board B was manufactured in the same manner by using a glass cloth treated with-(β-aminoethyl) -γ-aminopropylmethoxysilane. Further, a multilayer circuit board C was manufactured with a molding pressure of 4 MPa. This multilayer circuit board B was swollen for 30 seconds in a solder at 260 ° C. for 2 hours after the pressure cooker test for 2 hours. Further, voids were recognized, and the dimensional change of the inner layer circuit board (according to JIS C-6481) was 3σ = ± 0.008% (warp direction), 3σ = ± 0.
It was 006% (weft direction). The multilayer circuit board C is
After 4 hours from the pressure cooker test, it was dipped in solder at 260 ° C. for 30 seconds to generate blisters. Although no void was observed, the dimensional change of the inner layer circuit board was 3σ = 0.015% (warp direction), 3σ = 0.01, respectively.
It was 2% (weft direction).

Example 2 S glass fiber 60% by volume, tetrafluoroethylene resin fiber 4
0% by volume mixed woven fabric with a thickness of 0.1 mm (60 /
(25 mm × 58 pieces / 25 mm) was irradiated by a conveyor type ultraviolet irradiation device so that the cumulative irradiation amount became 700 mJ / cm ² (80 W, 1 minute). Next, this irradiation-treated woven fabric is N
-(Β-Aminoethyl) -γ-aminopropylmethoxysilane After being dipped in a 0.1% by weight aqueous solution, it was uniformly squeezed with a mangle so that the amount of the aqueous solution was 30 parts by weight with respect to 100 parts by weight of the woven fabric, and a hot air dryer And dried at 150 ° C. for 2 minutes. Next, an epoxy resin of NEMA standard FR-4 was impregnated into 55 parts by weight of the woven fabric so that the amount of resin adhered was 45 parts by weight to obtain a prepreg. Eight prepregs were stacked and pressure-molded at 170 ° C. and a pressure of 2 MPa for 1 hour to obtain a laminated plate. The heat resistance of the obtained laminate was 10 hours, and the dimensional change after the heat treatment (E-0.5 / 170) was −0.040 in the warp direction and −0.055 in the weft direction.
Moreover, no cracks or peeling occurred during drilling. Heat resistance is measured by boiling a 50 mm x 50 mm laminated plate test piece at normal pressure, immersing it in a solder bath at 260 ° C for 30 seconds, and then taking it out and checking for the presence of blisters or measling. It is represented by. For comparison, the laminated sheet produced in the same manner as in Example 2 except for UV irradiation had a heat resistance of 5 hours, and the dimensional change after the heat treatment was −0.110 in the warp direction and −0. 12
It was 0. Moreover, some cracks or peeling occurred during drilling.

Example 3 A mixed woven fabric (60/25 mm × 58/25 mm) having a thickness of 0.1 mm and composed of 60% by volume of S glass fiber and 40% by volume of polyetheretherketone resin fiber was used as a base material and A laminated board was obtained in the same manner as in Example 2. The heat resistance of the obtained laminate was 11 hours. The dimensional change after heat treatment is -0.035 in the warp direction and -0.040 in the weft direction.
Met. Also, no cracks or peeling occurred during drilling. For comparison, the laminate produced in the same manner as in Example 3 except that UV irradiation had a heat resistance of 6 hours,
The dimensional change after the heat treatment was −0.100 in the warp direction and −0.105 in the weft direction. Moreover, some cracks or peeling occurred during drilling.

Example 4 In Example 2, instead of the epoxy resin, maleimide-
A laminated board was obtained using the stililde resin under the same conditions as in Example 2 below. The heat resistance of the obtained laminate was 12 hours.
The dimensional change after the heat treatment was -0.035 in the warp direction and -0.040 in the weft direction. Also, no cracks or peeling occurred during drilling. For comparison, the heat resistance of the laminate produced in the same manner as in Example 4 except that the ultraviolet irradiation was 5 hours. The dimensional change after the heat treatment is -0.110 in the warp direction and -0.120 in the weft direction.
Met. Moreover, some cracks or peeling occurred during drilling.

Example 5 A woven fabric (60 fibers / 25 mm × 58 fibers / 25 mm) having a thickness of 0.1 mm and made of tetrafluoroethylene resin fibers has a good affinity with a fiber base material γ- (2-aminoethyl). Aminopropyltrimethoxysilane treatment was performed, and then a cumulative irradiation dose of 700 mJ / cm ² (80 W,
Irradiation for 1 minute). This woven cloth was impregnated with an epoxy resin so that the resin adhesion amount was 45 parts by weight with respect to 55 parts by weight of the woven cloth to prepare a prepreg, and a laminated board was obtained under the same conditions as in Example 2. The heat resistance of the obtained laminate was 8 hours. The dimensional change after heat treatment is
The value was 0.060 and the weft direction was -0.080. Also,
No cracking or peeling occurred during drilling. For comparison, the heat resistance of the laminate produced in the same manner as in Example 5 except that the ultraviolet irradiation was 3 hours. The dimensional change after the heat treatment was -0.130 in the warp direction and -0.150 in the weft direction. Also, cracking or peeling occurred during drilling.

[0024]

According to the present invention, since the affinity between the resin and the base material is improved, the impregnation property of the resin into the base material is improved, and the heat resistance, dimensional stability and reliability of the printed wiring board are improved. improves.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location B32B 17/04 7148-4F C08J 5/24 CFJ 7188-4F // B29K 105: 06 B29L 7:00 4F (72) Inventor Yoichi Kaneko 1500 Ogawa, Shimodate, Ibaraki Pref., Hitachi Chemical Co., Ltd. Shimodate factory (72) Inventor Takayuki Suzuki, 1500, Ogawa, Shimodate, Ibaraki Hitachi Chemical Co., Ltd. Shimodate factory

Claims (5)

[Claims] 1. A method for producing a prepreg, which comprises irradiating a fiber base material with ultraviolet rays, and then impregnating a resin varnish and drying the prepreg. 2. The method for producing a prepreg according to claim 1, wherein the fiber base material treated with the coupling agent is irradiated with ultraviolet rays, and then impregnated with a resin varnish and dried. 3. The method for producing a prepreg according to claim 1 or 2, wherein the fiber base material is a woven or non-woven fabric made of inorganic fibers. 4. The method for producing a prepreg according to claim 1 or 2, wherein the fiber base material is a woven or non-woven fabric made of organic fibers. 5. The method for producing a prepreg according to claim 1 or 2, wherein the fiber base material is a woven or non-woven fabric in which organic fibers and inorganic fibers are composited.