JPH0511759B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a method of manufacturing a glass fiber 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 foil-covered laminate used as a printed circuit board. BACKGROUND TECHNOLOGY AND PROBLEMS Japanese Patent Laid-open Nos. 55-4838 and 56-98136 disclose continuous manufacturing methods for electrical laminates. This method involves individually impregnating a plurality of base materials with a curable resin liquid while continuously conveying them in parallel, stacking and combining the impregnated base materials, and forming a cover sheet and/or metal foil. It consists of a continuous process such as laminating, curing continuously, and cutting. Electrical laminates are made by stacking multiple sheets of prepreg and forming them using a hot press. Glass cloth is placed on the outside, glass paper is placed on the inside, and an inorganic filler is placed on the inside glass paper base material. It is known to improve the dimensional stability of composite laminates by using resins containing high amounts of . If a composite laminate having a similar structure is to be manufactured by the continuous method described above, a resin liquid containing a large amount of inorganic filler must be supplied only to the inner nonwoven fabric substrate. However, it is not only inconvenient to separately supply resin liquids of different compositions to the substrates on the same line, but also has drawbacks such as the fact that the two types of recovered resin liquids are a mixture and cannot be reused as they are. There is. It is also possible to supply the outer glass cloth substrate with a high filler content resin having the same composition as the inner glass paper substrate, but it is not possible to increase the filler content too high because of clogging of the glass cloth. Therefore, it is an object of the present invention to solve these problems, difficulties, and drawbacks. Solution method In the present invention, a plurality of base materials each having a glass cloth on the outside and a non-woven fabric on the inside are continuously conveyed in parallel and are individually delivered to the row of base materials in a liquid state so that they react by reaction during curing. For electrical use, which includes the steps of impregnating a curable resin liquid that does not generate products, laminating and combining impregnated base materials, laminating a cover sheet and/or metal foil, curing continuously, and then cutting into desired dimensions. In the method of manufacturing a laminate, an inorganic filler is roughened and adhered to the nonwoven fabric base material using an organic binder, and the glass cloth is pretreated with a radical polymerizable curable resin liquid that has high adhesion to the glass cloth. This is a method for manufacturing a glass fiber reinforced electrical laminate, which is characterized by a process. In this way, by pre-adhering the inorganic filler to the nonwoven fabric base material that will become the core part,
The same composition of curable resin liquid can be used for impregnating all substrates, and it is also possible to selectively fill the core with a high amount of inorganic filler to improve dimensional stability. Become. When a double-sided metal foil-clad laminate is manufactured according to the present invention, the through-hole reliability of the resulting laminate is improved. At the same time, the glass cloth base material disposed on the outermost side is pretreated with a resin liquid to unevenly distribute the resin on the surface of the glass cloth, thereby improving the delamination strength. 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. In addition, since the glass cloth base material is impregnated with the curable resin liquid in advance, its wettability is improved, compared to impregnating untreated glass cloth.
Since the curable resin liquid highly filled with an inorganic filler can satisfactorily impregnate or adhere to the glass cloth substrate without clogging, it is possible to use a curable resin liquid highly filled with the inorganic filler. Furthermore, 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 liquid as the pretreatment resin liquid, the reaction time is short, productivity is high in a continuous manufacturing method, and curing agents such as amines and acid anhydrides are not required. It also avoids discoloration and deterioration of properties due to In addition, the viscosity of the radical polymerizable curable resin liquid can be adjusted using a crosslinking monomer, such as styrene, instead of a solvent, so there is no need to remove the solvent, and the residual solvent can be used after lamination curing. No defects such as foaming occur. Furthermore, since both the resin liquid used for pre-treatment of glass cloth and the resin liquid used for the main impregnation are radical polymerization type resin liquids, they crosslink with each other, and as in the method of JP-A No. 59-209829, Mechanical strength, including delamination strength, is considerably improved compared to when resins with different curing mechanisms are used for pretreatment and main impregnation. Preferred Embodiment In carrying out the present invention, the glass cloth base materials placed on both outer sides are used after being pretreated as described here, and the nonwoven fabric base material to which an inorganic filler is attached is placed on the inside. JP-A No. 55-4838, No. 56-1, except that processing is carried out while continuously conveying a row of substrates consisting of
98136 etc. can be applied. Incidentally, in the case of continuous curing, the equipment etc. are simple when curing is carried out substantially without pressure. Glass cloth is a cloth in which 50 to 800 yarns of glass filaments (usually about 9 μm in thickness) are woven vertically and horizontally using various weaving methods such as satin weave, plain weave, open weave, and twill weave. It is a general term for In the present invention, one layer of such glass cloth is used on each outer side. The resin used for pretreatment is preferably a resin that has higher adhesion to glass fibers than the impregnating resin, but may be the same as the impregnating resin in some cases. Examples of the resin used in the pretreatment include radical polymerizable curable resins such as unsaturated polyester resins, epoxy acrylate resins, polyester acrylate resins, urethane acrylate resins, and diallyl phthalate resins. When the impregnation resin is an unsaturated polyester resin, epoxy acrylate resins and urethane acrylate resins are particularly preferred as pretreatment resins. Rubber components may be incorporated or blended into the polymer backbone to improve adhesion, the amount being preferably between 2 and 50% by weight. A catalyst or polymerization initiator is required for curing of radical polymerizable resins. Organic peroxides are common as polymerization initiators, and a large number of them are known.
The aliphatic peroxides disclosed in the above are preferred, and it is particularly preferred to use those selected from aliphatic peroxyesters alone or in combination. Specifically, for example, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, acetyl peroxide, isobutyryl peroxide, t-butylperoxy-2 -ethylhexanoate, etc. Aliphatic peroxyesters include, for example, t-butylperoxyacetate, t-butylperoxyisobutyrate, t-butylperoxy-2-ethylhexanoate, t-butylperoxylaurate, etc. say. The pretreated resin liquid is used after being diluted to an appropriate viscosity with a solvent or a liquid polymerizable crosslinking monomer. The adhesion amount of the pretreatment resin liquid is 5 to 40 parts by weight, preferably 10 to 40 parts by weight of solid content per 100 parts by weight of glass cloth.
The amount is 30 parts by weight, more preferably 15 to 25 parts by weight. 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. The pretreatment method for the glass cloth is arbitrary, but for example, the pretreatment resin is diluted with 10 to 50% of a focusing monomer that also serves as a solvent, such as styrene, to prepare a pretreatment liquid with an appropriate viscosity, and then the glass cloth is prepared. It may be applied by coating, dipping, etc. In addition, 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, the pretreatment applied when impregnated with the curable resin liquid This is a preferred embodiment since it is possible to prevent a decrease in the treatment effect due to the resin dissolving into the subsequent impregnating resin liquid. Pretreatment can be integrated into the continuous laminate production line, or it can be carried out on a separate line.
It may also be used by winding it into a roll. The nonwoven fabric is a long sheet-like glass nonwoven fabric (glass paper) 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. Part of the nonwoven fabric can also be replaced with paper. The non-woven fabric has 1 layer on the inside depending on the board thickness.
A layer or several layers can be used. The inorganic filler used is water-insoluble and insulating. Examples include metal oxides such as silica, alumina, zirconia, titanium dioxide, and zinc white, metal hydroxides such as magnesium hydroxide and aluminum hydroxide, talc, kaolin, mica, wollastonite, and clay minerals. These include natural minerals, insoluble salts such as calcium carbonate, magnesium carbonate, barium sulfate, and calcium phosphate. Inorganic fillers that have a high specific gravity or a large shape tend to settle and are difficult to handle during processing. Moreover, the unevenness on the surface of the laminate after treatment becomes large, causing a poor appearance. Therefore, the aspect ratio of the shape is small,
Preferably, the particle size is 10 μm or less. Flame retardant aids and other substances that are generally added to laminates and that fall under the above definition of inorganic filler may be added in addition to the filler of the present invention. Examples of the organic binder include epoxy resin, melamine resin, polyvinyl alcohol, and acrylic resin. The amount of inorganic filler attached to the nonwoven fabric base material is
50 to 700 parts by weight per 100 parts by weight, preferably
100 to 600 parts by weight, more preferably 200 to 600 parts by weight
500 parts by weight. This amount of adhesion is determined in consideration of the balance between the dimensional stability improvement effect of the inorganic filler and the impregnating property of the impregnating resin liquid into the treated substrate. The amount of organic binder used is 1 to 60 parts by weight, preferably 2 to 40 parts by weight per 100 parts by weight of inorganic filler. This amount may be any amount that allows the inorganic filler to be adhered to the nonwoven fabric substrate in just the right amount and not enough to prevent powder from falling. The method of adhering to the nonwoven fabric substrate is arbitrary, but the inorganic filler and binder can be dispersed in a medium such as water to create a dispersion, the dispersion is supplied to the substrate by dipping, coating, etc., and then dried. This can be done by removing the medium. Nonwoven fabrics, especially glass paper, have a low density and do not have sufficient mechanical strength such as tensile strength, so problems such as cutting tend to occur in continuous manufacturing methods. However, by selecting an appropriate binder in this process, tensile strength It can reinforce the strength and avoid troubles such as cutting. One of the features of the continuous production method is that a curable resin liquid that is liquid itself and does not generate reaction by-products upon curing is used for impregnating the substrate. Such resins include unsaturated polyester resins, epoxy resins, epoxy acrylate resins, polyester acrylate resins, urethane acrylate resins, spiran resins, diallyl phthalate resins, and the like. According to the present invention, the above-mentioned inorganic filler can be added in an amount of 100 parts by weight or less, preferably 10 to 50 parts by weight, per 100 parts by weight of the impregnating resin.
This further improves dimensional stability in the thickness direction and improves through-hole reliability. The present invention will be explained in detail below with reference to Examples. Example: Both outermost layers of the base material layer have a thickness of 180 μm and a basis weight of 210
Use g/m ² glass cloth, with a basis weight of 40 in the middle.
A 1.6 mm thick double-sided copper foil-covered unsaturated polyester laminate was prepared using three layers of glass paper of g/m ² and 18 μm thick copper foil coated with 40 μm thick epoxy adhesive on both sides using a continuous method. It was manufactured using The glass paper is impregnated with a treatment liquid in which 100 parts by weight of water, 80 parts by weight of calcium carbonate, and 4 parts by weight of an epoxy binder are dispersed as an emulsion.
It was dried at 150° C. for 5 minutes, and 400 parts by weight of calcium carbonate was deposited on 100 parts by weight of the paper. The resin liquid for impregnation is a liquid uniformly mixed with 100 parts by weight of a flame-retardant unsaturated polyester resin (brome content: 14% by weight), 4 parts by weight of antimony trioxide, 1 part by weight of benzoyl peroxide, and 30 parts by weight of calcium carbonate. Using resin. The glass cloth is impregnated with a rubber-modified epoxy acrylate resin solution containing 50% styrene monomer.
Pretreatment was performed by heating at 160°C for 5 minutes. The amount of resin deposited at this time was 20% by weight in terms of solid content per 100 parts by weight of glass cloth. Pre-treated glass cloth is placed on the outermost sides of both sides, and glass paper is placed on the inside while being continuously conveyed.
After being individually impregnated with the resin liquid, they are combined and laminated with copper foil on both sides, and then continuously passed through a tunnel type curing furnace at 100°C for 15 minutes and at 150°C for 10 minutes.
Heat cured for minutes. Comparative Example 1 A double-sided copper foil-clad laminate with a thickness of 1.6 mm was manufactured by the same procedure as in the example except that glass paper was used without being treated with an inorganic filler. Comparative Example 2 A double-sided copper foil-clad laminate with a thickness of 1.2 mm was produced in the same manner as in the example except that the glass cloth was not pretreated. The performance of the laminates of Examples and Comparative Examples is shown in the table below.

【table】

[Table] (1) Evaluation method for through-hole reliability: A sample of 200 double-sided copper through-holes with a diameter of 1 mmφ connected in series was heated at 20°C for 20 seconds and then at 260°C.
The cycle of immersion for 10 seconds is repeated, and it is expressed as the number of cycles until the rate of change in electrical resistance value at high temperature exceeds 10%. (2) The interlayer peel strength is measured according to the JIS S-5012 method for measuring conductor peel strength using a test piece cut to a width of 1 cm. (3) 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 distance moved in the orthogonal direction from the straight line per meter when viewed from the plane of the glass cloth.

Claims (1)

[Claims] 1. While continuously conveying a plurality of base material rows in which glass cloth is arranged on both outer sides and non-woven fabric on the inner side in parallel, the base material rows are individually reacted in a liquid state themselves during curing. An electric method that includes the steps of impregnating a curable resin liquid that does not generate by-products, laminating and combining the impregnated base materials, laminating a cover sheet and/or metal foil, curing continuously, and then cutting into desired dimensions. In the method for manufacturing a laminate for use in glass cloth, 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,
A continuous manufacturing method for a glass fiber reinforced electrical laminate, characterized in that an inorganic filler is preliminarily attached to the nonwoven fabric base material using an organic binder. 2. The method according to item 1, wherein the radically polymerizable curable resin used in the pretreatment has higher adhesion to the glass cloth than the impregnating resin. 3. The method according to item 1, wherein the radically polymerizable curable resin liquid used in the pretreatment is an epoxy acrylate resin liquid or a urethane acrylate resin liquid. 4. The method according to item 3, wherein the epoxy acrylate resin liquid or urethane acrylate resin liquid used in the pretreatment contains a rubber component of 2 to 50% by weight. 5 In the pretreatment, the amount of resin attached to the glass cloth is 5 to 40% per 100 parts by weight of the glass cloth.
The method according to any one of items 1 to 4, wherein the amount is parts by weight. 6. The method according to any one of items 1 to 5, wherein the pretreatment resin liquid is an epoxy acrylate resin, and the impregnation resin liquid is an unsaturated polyester resin. 7 The amount of inorganic filler adhered to the nonwoven fabric base material is
7. The method according to any one of items 1 to 6, wherein the organic binder is used in an amount of 50 to 700 parts by weight per 100 parts by weight, and the amount of organic binder used is 1 to 60 parts by weight per 100 parts by weight of the inorganic filler. 8. The method according to any one of items 1 to 7, wherein the inorganic filler is contained in an amount of 1 to 50 parts by weight per 100 parts by weight of the curable resin impregnated into the base material.