JPH04262322A - Manufacture of glass cloth reinforced electrical laminated plate - Google Patents

Abstract

PURPOSE:To improve exfoliation strength, soldering heat resistivity, the hygroscopic property of a laminated plate by pretreating the glass cloth of the outermost layer in advance with a rubber including a radical polymerized type double bond and using a specific radical polymerized type hardenable resin as an impregnating resin. CONSTITUTION:A glass cloth base material is pretreated with a rubber compound resin solution including a radical polymerized double bond. At least two layers of base material lines on both outer sides of which the glass clothes are arranged, are parallely and continuously conveyed, and a radical polymerized type hardenable epoxyacrylate resin unit which is liquid in itself and does not generate a reaction product upon hardening, or a mixture solution of an epoxyacrylate resin and an unsaturated polyester resin, is individually impregnated in the base material lines. The resultant products are stacked and integrated, subjected to lamination of cover sheets and/or metal foils thereon and continuously hardened, followed by being cut in a desired dimension so as to produce an electrical laminated plate.

Description

[Detailed description of the invention]

(Industrial Field of Application) The present invention relates to a method of manufacturing a glass cloth reinforced electrical laminate. Here, the electrical laminate refers to an insulating laminate used as a substrate for various electrical and electronic components, and a metal-clad laminate used as a printed circuit board.

(Prior art) Japanese Patent Application Laid-Open No. 62-2 by the present applicant
No. 68632 and the like discloses a method for manufacturing a glass cloth reinforced electrical laminate. This method involves continuously conveying at least two layers of substrates in parallel with glass cloth arranged on both outer sides, and applying radicals, which are themselves liquid and do not generate reaction by-products during curing, to the substrates individually. A method for manufacturing an electrical laminate, which includes the steps of impregnating a polymeric resin liquid, laminating and combining impregnated base materials, laminating a cover sheet and/or metal foil, continuously curing, and then cutting into desired dimensions. A method for producing a glass cloth reinforced electrical laminate, characterized in that the glass cloth is pretreated with a radically polymerizable curable resin liquid that has higher adhesion to the glass cloth than the impregnating resin liquid.

[0003] When manufacturing a laminate having at least two layers of substrates with glass cloth on both sides using the continuous manufacturing method described above, if the adhesion between the impregnating resin and the pretreatment solution is not high, the outermost glass In some cases, the interlayer peel strength between the cloth base material and the inner base material layer was insufficient. This is the case, for example, when an epoxy acrylate resin is used as the pretreatment solution and an unsaturated polyester resin is used as the impregnating resin liquid.

[0004] JP-A-59-209829 proposes, in a continuous manufacturing method of glass-based unsaturated polyester resin laminates, to impregnate a glass substrate with an epoxy resin and pre-treat it. However, epoxy resin generally takes a long time to fully cure, and shrinking it shortens the pot life of the resin liquid.
Not suitable for continuous manufacturing methods. Furthermore, since epoxy resins require amines or acid anhydrides as curing agents, there are problems in that they become heavily colored when heated and their physical properties deteriorate significantly, resulting in a decrease in commercial value. Furthermore, epoxy resin has a high viscosity,
Since it has poor impregnating properties, it is usually used after being diluted with a solvent, and it is necessary to completely dry and volatilize it. Therefore, it is an object of the present invention to solve these problems, difficulties, and drawbacks.

(Solution Method) In the present invention, at least two layers of substrates having glass cloth arranged on both outer sides are continuously conveyed in parallel, and the substrates themselves are individually coated in a liquid state during curing. Impregnated with a radical polymerizable curable epoxy acrylate resin solution that does not generate reaction products or a mixed solution of epoxy acrylate resin and unsaturated polyester resin, laminated and combined the impregnated base materials, and then laminated with a cover sheet and/or metal foil. , a method for manufacturing an electrical laminate including a step of continuously curing and then cutting into desired dimensions, characterized in that the glass cloth is pretreated with a rubber compound resin liquid containing a radically polymerizable double bond. This is a method for manufacturing a glass cloth reinforced electrical laminate.

[0006] In this way, the glass cloth base material disposed on the outermost layer side is pretreated with a rubber compound resin solution containing radically polymerizable double bonds, and the impregnating resin is epoxy acrylate resin alone or epoxy acrylate resin and unsaturated resin. Adhesion is increased by mixing polyester resin,
It is possible to improve the delamination strength. Furthermore, the metal foil-clad laminate has improved soldering heat resistance and moisture absorption. At this time, if only unsaturated polyester resin is used as the impregnating liquid, the adhesion to the rubber compound resin as the pretreatment liquid will be low, and no improvement in interlayer peel strength can be expected. Furthermore, by filling the weave of the glass cloth with a pretreated resin, the surface smoothness of the metal foil surface is improved, which is advantageous for forming fine printed circuits. Further, by making the weave of the glass cloth stronger through pre-treatment, it is possible to prevent the weave from bending during running, thereby achieving effects such as reducing warping and twisting of the laminate.

Since the present invention uses a radically polymerizable curable resin as the pretreatment resin liquid, the reaction time is short, productivity in continuous production is high, and curing agents such as amines and acid anhydrides are not required. Discoloration and deterioration of physical properties due to heating can also be avoided. In addition, since the viscosity of the radical polymerization type cured resin liquid can be adjusted using a crosslinking monomer such as styrene instead of a solvent, there is no need to remove the solvent, and it is possible to prevent foaming after lamination and curing due to residual solvent. No defective products occur. In addition, the resin liquid used for pre-treatment of glass cloth and the resin liquid used for the main impregnation are originally radical polymerization type resin liquids, so they crosslink with each other.
Mechanical strength including interlayer peel strength is considerably improved compared to the case where resins with different curing functions are used for pretreatment and main impregnation as in the method of -209829.

(Preferred Embodiment) In carrying out the present invention, an epoxy acrylate resin alone or a mixture of an epoxy acrylate resin and an unsaturated polyester is used as the impregnating liquid, and the glass cloth substrates disposed on both outer sides are made of the radicals described here. JP-A-55-4838, JP-A-56-98136, JP-A-62-26 of the present applicant, except that it is used after pretreatment with a rubber compound resin having a polymerizable double bond.
8632 etc. can be applied.

[0009] Glass cloth is made by weaving yarns made of 50 to 800 glass filaments, usually about 9 μm thick, woven vertically and horizontally using various weaving methods such as satin weave, plain weave, open plain weave, and twill weave. It is a general term for cloth. In the present invention, such glass cloth is pretreated and used, for example, in one layer on each outer side.

The resin used in the pretreatment of glass cloth in the present invention is a resin obtained by introducing a radically polymerizable double bond into the molecular chain end or backbone of a rubber compound. A typical example is commercially available maleated polybutadiene resin. Similarly, maleated butadiene copolymers such as nitrile rubber can also be used. Another example is a rubber compound in which a butadiene polymer or copolymer is oxidized with peracetic acid, etc. to epoxidize it, and the epoxy ring is opened with (meth)acrylic acid to introduce a pendant (meth)acryloyl group. and so on.

[0011] Although it is preferable to use a catalyst or a polymerization initiator for curing the resin, it is not always necessary. Organic peroxides are commonly used as polymerization initiators.
Although many are known, for the purpose of the present invention:
Aliphatic peroxides disclosed in JP-A-55-53013 are preferred, and it is particularly preferred to use aliphatic peroxyesters alone or in combination.

Specific examples include di-t-butyl peroxide, 2,5-dimethyl-2,5-(t-butylperoxy)hexane, acetyl peroxide, and isobutyryl peroxide.

Aliphatic peroxyesters include, for example, t-butylperoxyacetate, t-butylperoxyisobutyrate, t-butylperoxy-2-ethylhexanoate, and t-butylperoxylau. Refers to rate, etc.

The pretreated resin liquid is used after being diluted to an appropriate viscosity with a solvent or a liquid polymerizable crosslinking monomer. The amount of the pretreatment resin liquid applied is 5 to 40 parts by weight, preferably 10 to 30 parts by weight, and more preferably 10 to 20 parts by weight as solid content per 100 parts by weight of glass cloth. If the amount is too large, the impregnating properties of the impregnating resin will be reduced, and if the amount is too small, the desired effect will not be fully exhibited.

[0015] The pretreatment method for the glass cloth is arbitrary, but for example, the pretreatment resin may be diluted with 10 to 50% of a polymerizable monomer that also serves as a solvent, such as styrene, to prepare a pretreatment liquid with an appropriate viscosity. It may be applied by coating on glass cloth, dipping, etc.

Furthermore, since a curing catalyst such as an organic peroxide is added to the pretreatment resin liquid, if the glass cloth is semi-cured after adhesion, it will not adhere when impregnated with the curing resin liquid later. This is a preferred embodiment since it is possible to prevent a decrease in the treatment effect due to the pretreated resin being dissolved in the subsequent impregnation resin solution. The pretreatment can be carried out by incorporating it into a continuous laminate production line, or it can be wound into a roll for use.

[0017] Glass cloth may be used as the base material of the intermediate layer, or a composite structure may be formed using nonwoven fabric. When using glass cloth, it can also be treated in the same way as the glass cloth base material disposed on the outermost layer. The nonwoven fabric is a long sheet-shaped glass nonwoven fabric (also known as glass paper) that is made by wet-forming glass fibers with a thickness of 1 to 20 μm dispersed in water and using acrylic resin, polyvinyl alcohol, epoxy resin, melamine resin, etc. as a binder. There are also glass-mixed papers made of paper and glass fibers, synthetic fibers such as polyester, and non-woven fabrics made of rayon, asbestos, rock wool, etc. When the purpose is CEM1, the intermediate base material may be paper. The base material layer of the intermediate base material can be one layer or several layers depending on the plate thickness. However, in the case of the thinnest plate, only one layer of glass cloth is provided on both sides in the present invention, and the intermediate base material may be omitted.

[0018] One of the characteristics of the continuous manufacturing method is that
As shown in 838, 56-98136, 62-268632, etc., radical polymerizable curable resin liquids that are liquid themselves and do not generate reaction by-products during curing are used for impregnating substrates. . In the present invention, in order to improve the adhesion with the pretreatment liquid, a rubber compound resin having radically polymerizable double bonds, an epoxy acrylate resin alone or a resin liquid containing an epoxy acrylate mixed with an unsaturated polyester resin is used as the impregnation liquid. do. At this time, the mixing amount is 50 to 2000 parts by weight, preferably 10 parts by weight, of unsaturated polyester per 100 parts by weight of epoxy acrylate resin.
The amount is 0 to 1000 parts by weight, more preferably 170 to 400 parts by weight. If the amount of unsaturated polyester is 2000 parts by weight or more, the adhesion to the glass cloth pretreatment resin will not improve, and if it is less than 50 parts by weight, the cost will increase. Further, although it is common to mix an inorganic filler such as aluminum hydroxide with these impregnating liquids, this is not necessarily necessary in the present invention. The present invention will be explained in detail below with reference to Examples.

(Example) Both outermost sides of the base material layer have a thickness of 180 mm.
A glass cloth with a basis weight of 210 g/m2 is used, two layers of glass paper with a basis weight of 40 g/m2 are used in the middle, and an epoxy resin adhesive layer is applied to a thickness of 40 μm.Thickness 1
A double-sided copper-clad unsaturated polyester laminate having a thickness of 1.2 mm and having 8 μm copper foil on both sides was manufactured by a continuous manufacturing method. The glass cloth is made from a polybutadiene resin solution (molecular weight approximately 3
000) and heated at 160° C. for 5 minutes for pretreatment. The amount of resin deposited at this time was 15% by weight in terms of solid content per 100 parts by weight of glass cloth. As a resin for impregnation,
70 parts by weight of flame-retardant unsaturated polyester resin (brome content 14% by weight), 30 parts by weight of epoxy acrylate resin,
A liquid resin was used in which 4 parts by weight of antimony trioxide, 1 part by weight of benzoyl peroxide, and 30 parts by weight of aluminum hydroxide were uniformly mixed. Place pretreated glass cloth on both outermost sides.
While each substrate is continuously conveyed with glass paper placed inside, it is impregnated with the resin individually and then combined, and after laminating copper foil on both sides, it is continuously transported in a tunnel type curing furnace. 15 min at 100°C and 10 min at 150°C.
Heat cured for minutes.

(Comparative Example 1) A glass cloth with a thickness of 1.2 mm was prepared by the same procedure as in Example, except that the glass cloth was pretreated with a urethane acrylate resin containing 50% by weight of styrene monomer.
A double-sided copper-clad laminate of mm was manufactured.

(Comparative Example 2) A glass cloth with a thickness of 1.2 m was prepared by the same operation as in the example except that the glass cloth was not pretreated.
A double-sided copper-clad laminate of 1.0 m was manufactured.

The performance of Examples and Comparative Examples is shown in the table below.

[Table 1] 1) The interlayer peel strength is measured according to the method for measuring conductor peel strength according to JIS S 5012 using a test piece cut to a width of 1 cm. 2) Eye curvature refers to the deviation of the glass cloth from the original straight line, and the amount of eye curvature is expressed as the amount of movement per 1 m in the perpendicular direction from the straight line when viewed from the plane of the glass cloth. 3) Water absorption was measured according to JIS C 6481.

Claims (7)

[Claims] Claim 1: Continuously conveying at least two layers of substrates in parallel with glass cloth arranged on both outer sides, the substrates themselves are in liquid form and generate reaction by-products during curing. Manufacturing of electrical laminates, which includes the steps of impregnating with an unsaturated resin liquid, laminating and combining impregnated base materials, laminating a cover sheet and/or metal foil, continuously curing, and then cutting into desired dimensions. In the method, the glass cloth is pretreated with a rubber compound resin solution containing a radically polymerizable double bond, and then a radically polymerizable curable epoxy acrylate resin solution alone or in combination with the unsaturated resin solution for impregnation is applied to the base material. A method for manufacturing a glass cloth-reinforced electrical laminate, which comprises impregnating a glass cloth reinforced electrical laminate with a mixed solution with a saturated polyester resin solution. 2. The method according to claim 1, wherein the rubber compound containing a radically polymerizable double bond used in the pretreatment is a maleated butadiene polymer or copolymer. 3. The method according to claim 1 or 2, wherein the amount of the rubber compound containing the radically polymerizable double bond attached to the glass cloth in the pretreatment is 5 to 40 parts by weight as solid content per 100 parts by weight of the glass cloth. Method described. 4. The unsaturated resin liquid for impregnation contains 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight, more preferably 170 to 400 parts by weight of unsaturated polyester resin per 100 parts by weight of epoxy acrylate resin. 4. A method according to any one of claims 1 to 3, comprising: 5. The method according to claim 1, wherein the inner substrate disposed between the outer glass substrates is also a glass cloth. 6. The method according to claim 1, wherein the inner substrate disposed between the outer glass substrates is a nonwoven fabric. 7. The method according to claim 6, wherein the nonwoven fabric is glass paper.