JPH0559597B2 - - Google Patents

Description

[Detailed description of the invention]

"Field of Industrial Application" The present invention relates to printed circuit boards used in electrical equipment, electronic equipment, communication equipment, and the like. ``Prior Art'' Conventionally, printed circuit boards have been manufactured by forming electrical circuits on laminates such as paper-based phenolic resin laminates, paper-based unsaturated polyester resin laminates, or glass cloth-based epoxy resin laminates. ing. The laminates used for these printed circuit boards are manufactured by impregnating base materials with resin, laminating them, and curing them by heating. ``Problems to be Solved by the Invention'' However, when a laminate is manufactured using a phenolic resin, reaction by-products such as water are generated as the phenolic resin hardens, and these reaction by-products affect the physical properties of the laminate. That is, there is a problem in that it adversely affects the physical properties of printed circuit boards using it, and in order to avoid this, it is usually necessary to apply excessive pressure using a large press or the like. Furthermore, a laminate using a phenolic resin and a printed circuit board using this laminate have a drawback that electrical properties such as dielectric constant, dielectric loss tangent, and tracking resistance are low. In addition, when manufacturing laminates using paper-based phenolic resin or glass cloth-based epoxy resin, the resin is usually dissolved in a solvent to form a solution, and the base material is impregnated with this solution. Laminates have been manufactured by removing the solvent from the impregnated substrate to form an intermediate called prepreg, and laminating the prepregs under pressure at high temperatures. However, when a laminate is manufactured using such a prepreg method, there are problems in that raw material costs and equipment costs are high, and the process is complicated. In order to solve these problems, a paper-based laminate made of unsaturated polyester resin was proposed, but since unsaturated polyester resin inherently has poor heat resistance, the laminate and this laminate were The printed circuit board used also has problems such as low rigidity when hot and insufficient strength when hot. The present invention was made in view of the above circumstances, and
The object of the present invention is to provide a printed circuit board that can be manufactured without using the prepreg method and has good physical properties such as rigidity and strength when hot. "Means for Solving the Problem" As a result of various studies, the present inventors dissolved an allyl ester resin having an allyl ester group at the end of a polyester composed of a polybasic acid and a polyhydric alcohol, and an allyl ester resin. and a radically polymerizable liquid crosslinkable monomer as an essential component, the substrate is impregnated with an impregnating liquid, and the impregnated substrates are laminated to form a laminated board. The inventors have discovered that the above object can be achieved and have completed the present invention. That is, the problems in manufacturing paper-based phenolic resin laminates and glass cloth-based epoxy resin laminates are solved by using the above impregnating liquid, and the laminates are formed using this impregnating liquid. By forming an electric circuit on a laminate to make a printed circuit board, it has higher physical properties when hot than a printed circuit board made by forming an electric circuit on a laminate manufactured using unsaturated polyester resin. It is possible to obtain a printed circuit board with better electrical characteristics than a printed circuit board formed by forming an electric circuit on a laminate made of phenolic resin. Hereinafter, the printed circuit board of the present invention will be explained in detail. The allyl ester resin used in the present invention is a polyester composed of a polybasic acid and a polyhydric alcohol, and has an allyl ester group at at least one terminal thereof. Examples of the polybasic acids include dibasic acids such as orthophthalic acid, orthophthalic anhydride, isophthalic acid, phthalic acids such as terephthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, endomethylenetetrahydrophthalic acid, and methylendomethylenetetrahydrophthalic acid. Hydrophthalic acids such as phthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid and their acid anhydrides, aliphatic dibasic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, tetrabromophthalic acid, tetrachloro Examples include halogenated dibasic acids such as phthalic acid, chlorendic acid, and their acid anhydrides;
Examples of trifunctional or higher-functional polybasic acids include trimellitic acid, pyromellitic acid, and acid anhydrides thereof. These polybasic acids can be used alone or in combination. In addition, as polyhydric alcohols, ethylene glycol, 1,2-propylene glycol, 1,4
-butanediol, 1,6-hexanediol,
In addition to dihydric alcohols containing aliphatic, alicyclic or aromatic compounds such as neopentyl glycol, 1,4-cyclohexanedimethanol, paraxylene glycol, etc. (R is hydrogen or a chain alkyl group, n is 2
Examples include dihydric alcohols obtained by the addition reaction of alkylene oxides such as ethylene oxide and propylene oxide (an integer of ~10). Examples of trihydric or higher polyhydric alcohols include aliphatic trihydric alcohols such as glycerin and trimethylolpropane, and tetrahydric or higher alcohols such as pentaerythritol and sorbitol. Other examples include aliphatic, alicyclic, and aromatic halogenated polyhydric alcohols containing halogen atoms, such as dibromneopentyl glycol and adducts of tetrabrombisphenol A with ethylene oxide or propylene oxide. These can be used alone or in combination. The method for producing the allyl ester resin is not particularly limited, and may be any known method such as the method proposed in Japanese Patent Application No. 63-262217. For example, there is a method in which a diallyl ester of a dibasic acid such as diallyl terephthalate and the above-mentioned polyhydric alcohol are charged into a reactor together with a transesterification catalyst and reacted while distilling off allyl alcohol. In addition, as an industrially more effective method, instead of diallyl terephthalate, a dialkyl ester of a dibasic acid such as dimethyl terephthalate and allyl alcohol are charged into a reactor together with a polyhydric alcohol and a transesterification catalyst to produce by-products such as methanol. A method is used in which the alcohol is reacted while being distilled off. Further, depending on the reaction temperature, a polymerization inhibitor such as hydroquinone may be allowed to coexist in the reaction solution. In this way, an allyl ester resin having an allyl group at at least one end of the polyester is produced. This allyl ester resin may be used alone or in combination of two or more types. In addition, by selecting various types of the polybasic acid and polyhydric alcohol, the type of allyl ester resin can be varied, and from among these various allyl ester resins, the most suitable one is selected, By manufacturing a printed circuit board using this, it is possible to obtain a printed circuit board with good electrical properties, punchability, flame retardancy, etc. while maintaining heat resistance. Further, the crosslinking monomer used in the present invention refers to a monomer having a radically polymerizable carbon-carbon double bond. Examples of such crosslinking monomers include diallyl orthophthalate, diallyl isophthalate, diallyl terephthalate, styrene, α-methylstyrene, chlorostyrene, vinyltoluene, divinylbenzene, methyl (meth)acrylate, and ethyl (meth)acrylate. , butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, benzyl (meth)acrylate, acrylonitrile, vinyl acetate, allyl acetate, acrylamide, vinyl chloride,
Examples include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and the like. These crosslinking monomers may be one type or two types.
More than one type may be mixed and used. Organic peroxides are suitable as the curing catalyst used when radical polymerizing the allyl ester resin and the crosslinkable monomer. Examples of such organic peroxides include ketone peroxides such as methyl ethyl ketone peroxide and acetylacetone peroxide, 1,1-bis(t-butylperoxy)3,
3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane,
Peroxyketals such as 2,2-bis(t-butylperoxy)octane, n-butyl-4,4-bis(t-butylperoxy)valerate,
t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, 2,5-dimethylhexane-2,
5-hydroperoxide, 1,1,3,3-
Hydroperoxides such as tetramethylbutyl hydroperoxide, di-t-butyl peroxide, t-butylcumyl peroxide,
Dicumyl peroxide, α,α′-bis(t-butycumyl peroxide, α,α′-bis(t-butylperoxy-m-isopropyl)benzene,
Dialkyl peroxides such as 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3, acetyl peroxide , iso-butyryl peroxide, octanoyl peroxide, decanoyl peroxide,
Diacyl peroxides such as lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, di-
iso-propyl peroxydicarbonate, di-
2-ethylhexyl peroxydicarbonate,
Di-n-propyl peroxydicarbonate, dimyristyl peroxydicarbonate, di-2-
Peroxydicarbonates such as ethoxyethyl peroxydicarbonate, dimethoxy-iso-propyl peroxydicarbonate, di(3-methyl-3-methoxybutyl)peroxydicarbonate, diallyl peroxydicarbonate, t
-butyl peroxy acetate, t-butyl peroxy-iso-butyrate, t-butyl peroxy pivalate, t-butyl peroxy neodecanoate, cumyl peroxy neodecanoate, t
-butylperoxy-2-ethylhexanoate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, t-butylperoxybenzoate, di-t-butyldi peroxy-iso-phthalate,
2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butylperoxyisopropyl carbonate, cumylperoxyoctoate, t-hexylperoxyneodecanoate, t-butylperoxyneodecano Eight, t
Examples include peroxy esters such as -hexyl peroxy pivalate, t-hexyl peroxy neohexanoate, and cumyl peroxy neohexanoate. These organic peroxides can be used alone or in combination of two or more depending on the type of resin and curing conditions. Furthermore, although such organic peroxides are suitable as curing catalysts, the present invention is not limited thereto, and other curing catalysts may be used. In the present invention, the amount of allyl ester resin in the resin content of the impregnating liquid is 40 to 95% by weight, preferably 50% by weight.
~90% by weight, and the amount of crosslinking monomer is 5% by weight.
It is preferably within the range of ~60% by weight, preferably 10-50% by weight. If the allyl ester resin is less than 40% by weight, the crosslinking density will decrease and the original heat resistance will decrease, and if it is more than 95% by weight, the viscosity of the impregnating liquid will increase and it will be difficult to handle when impregnating the base material. This is not desirable because it becomes difficult. In addition, the purpose of blending crosslinking monomers is to simplify the manufacturing process by manufacturing laminates without using the prepreg method that uses solvents, etc. The first objective is to lower the viscosity of the allyl ester resin. Additionally, depending on the type of crosslinking monomer, there are advantages such as increasing the curing speed through radical reactions and lowering material costs, but if the amount is too large, it may impair the inherent heat resistance of the allyl ester resin. become. Therefore, if the amount of the crosslinking monomer is less than 5% by weight, handling during impregnation becomes difficult, and if it is more than 60% by weight, the inherent heat resistance of the allyl ester resin will be affected as described above. This is not preferable because it reduces the The impregnation liquid used in the present invention may contain flame retardants, additive plasticizers, fillers (for example, particles of aluminum hydroxide, etc.), stabilizers, lubricants, inorganic pigments, reinforcing materials, colorants, and release agents. Various additives such as molding agents and curing accelerators can also be added. Particularly in obtaining printed circuit boards, flame retardant treatments are important. Methods of making flame retardant using additive-type flame retardants or reactive-type flame retardants are used. Additive flame retardants include phosphorus flame retardants such as trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, triphenyl phosphite, tris(chloroethyl) phosphate, chlorinated paraffin, and decabrom diphenyl ether. , halogenated flame retardants such as tetrabrom diphenyl ether, antimony compounds such as antimony trioxide and antimony pentoxide, zinc borate and aluminum hydroxide. Further, as the reactive flame retardant, a reactive halogen-containing flame-retardant vinyl monomer is preferable from the viewpoint of flame retardancy and physical properties of the resulting resin. Particularly preferably, monoglycidyl methacrylate or monoglycidyl acrylate is added to an esterified product of a polyhydric alcohol having an aliphatic or alicyclic saturated hydrocarbon group containing bromine or chlorine having 1 to 18 carbon atoms and a saturated polybasic acid. Examples include halogen-containing flame-retardant vinyl monomer 1, which is represented by the following formulas, and bromine-containing flame-retardant vinyl monomers 2 and 3, which are represented by general formulas A and B. In addition, in the general formula, R ₁₁ , R ₁₂ and R ₁₃ represent hydrogen or a methyl group. The polyhydric alcohol used in the synthesis of flame retardant monomer 1 is an aliphatic or alicyclic alcohol with 1 carbon number.
-12 alcohols are preferred, and dibromeneopentyl glycol can be mentioned as an easily available alcohol, but is not limited thereto. Moreover, the flame retardant monomers 2 and 3 can be synthesized by an esterification reaction between dibrome neopentyl glycol and methacrylic acid. The type and proportion of these flame-retardant monomers to be added are selected depending on the demand for flame-retardant printed circuit boards, but it is preferable that they be added to the impregnating liquid in an amount of 5 to 70% by weight. If the amount added is less than 5% by weight, no improvement in flame retardancy can be expected, and if it exceeds 70% by weight, physical properties other than flame retardance will deteriorate, which is not preferable. In addition, as a flame retardant method, a method using a halogen atom as a part of the constituent elements of the allyl ester resin, a method using an additive type flame retardant, a method using a reactive type flame retardant, etc. can be used in combination. It is possible. Next, a method for manufacturing a printed circuit board using the above-mentioned impregnating liquid will be explained. First, as an example of a method for manufacturing a laminate used for printed circuit boards, a base material is impregnated with the above impregnating liquid, a plurality of impregnated base materials are laminated (for example, 2 to 20 sheets), and Examples include methods such as heating under pressure and hardening and molding. As the above-mentioned base material, the same base materials as conventionally used for laminates can be used, such as glass fiber cloth, glass non-woven cloth, etc.
Examples include paper mainly composed of cellulose fibers such as kraft paper and linter paper, and sheets or strips made of inorganic fibers such as asbestos. When paper is used as the base material, from the viewpoint of impregnability and quality, it is preferable to use paper mainly composed of cellulose fibers, such as kraft paper, which has an air-dried density of 0.3 to 0.7 g/cm ³ . Before impregnating these substrates with the impregnating liquid, it is preferable to perform an impregnating drying treatment using a treatment agent such as a silane coupling agent, methylol melamine, methylol phenol, methylol guanamine, or N-methylol compound. By performing such treatment, it is possible to improve the electrical characteristics of the manufactured printed circuit board. The thickness of the laminate used in the printed circuit board of the present invention varies depending on the type of base material, the composition of the resin composition to be impregnated, and the use of the laminate, but is usually 0.5 to 3 mm.
It is. Further, the proportion of the resin composition in the laminate is about 30 to 80% by weight. The printed circuit board of the present invention can be obtained by forming an electric circuit on such a laminate. As a method for forming an electric circuit, a commonly used etched oil method or additive method is used. An electric circuit is formed using the etched oil method,
In order to manufacture a printed circuit board, it is necessary to bond copper foil to the laminate in advance. As this copper foil, electrolytic copper foil is commercially available for use in printed circuit boards, and it is preferable to use this from the viewpoints of corrosion resistance, etching properties, and adhesive properties, but the present invention is limited to this. It is not something that can be done. The thickness of the copper foil is preferably about 10 to 100 microns. In order to effectively bond the copper foil and the base material,
It is preferable to use an adhesive, and the adhesive is preferably a liquid or semi-liquid adhesive that does not generate unnecessary side reaction products during the curing process. Examples of such adhesives include acrylate adhesives, epoxy resin adhesives, epoxy acrylate adhesives, isocyanate adhesives, and various modified adhesives thereof. Epoxy resin adhesives are preferred in terms of adhesiveness and tracking resistance.
As the epoxy resin, bisphenol A type is preferred, and as the amine curing agent used therein, any amine curing agent that is commonly used as an amine type curing agent such as aliphatic amines and aromatic amines can be used. It may be. Further, polyamide resin, terminal amino group polybutadiene nitrile rubber, etc. can also be used. A mixture of the above curing agents may also be used. In order to obtain this copper-clad laminate, the laminate used in the present invention may be formed once and then copper foil may be laminated thereon using the above-mentioned adhesive, or the copper foil may be laminated on top of the laminate using the above-mentioned adhesive. At the same time, they may be bonded together to form a copper-clad laminate with or without the above adhesive. A printed circuit board is obtained by etching the copper-clad laminate thus obtained to form an electric circuit. In addition, in the case of an additive method, a method is used in which copper is deposited on the above-mentioned laminate by electroless plating and, if necessary, electrolytic plating in the areas necessary for forming an electric circuit. "Examples" Hereinafter, the resin composition for a laminate of the present invention and a laminate using this resin composition will be specifically explained using Examples, but the following Examples will limit the present invention. It's not a thing. [Production of Allyl Ester Resin A] 610 g of diallyl terephthalate, 80 g of ethylene glycol, and 0.1 g of dibutyltin oxide are charged into a three-necked flask equipped with a distillation device and heated to 180°C under a nitrogen stream to produce allyl alcohol. was removed. allyl alcohol
After distilling about 143g, the inside of the flask was adjusted to 50mmHg.
The distillation rate was increased by reducing the pressure to . After the theoretical amount of allyl alcohol was distilled off, unreacted diallyl terephthalate was distilled off at 1 mmHg while the reaction solution was maintained at 200° C. using a thin film evaporator. The reaction solution was poured into a vat, cooled, and pulverized to obtain a powdery allyl ester resin (). Furthermore, allyl ester resins () and () were obtained using the same method as the method for obtaining the allyl ester resin () above, except that the materials shown in Table 1 were used. Table 1 shows the materials used and their blending amounts.

[Manufacture of unsaturated polyester resin]

101 g of propylene glycol and 84 g of isophthalic acid were placed in a separable flask equipped with a stirrer, a thermometer, a gas inlet tube, and a condenser, and the mixture was reacted at 185°C for 3 hours under nitrogen bubbling conditions while distilling condensed water. Ta. Next, add 88g of fumaric acid and then heat to 185°C.
The mixture was allowed to react for 6 hours. Finally, the pressure inside the system was reduced to about 12 mmHg, and the temperature inside the flask was raised to 200°C to complete the reaction, and a resin with an acid value of 30 was obtained. This resin was dissolved in styrene to obtain an unsaturated polyester resin (2) with a styrene concentration of 45%. (Examples 1 to 3) Kraft paper with a basis weight of 135 g/m ² was coated with Nikaresin S-
305 (trade name, Nippon Carbide Methylol Melamine) Soaked in an aqueous solution, squeezed with a roller, and heated at 120℃ for 30 minutes.
Dry for a minute. The resulting paper base contains 15 methylolmelamine.
% by weight was spread. This paper was floated in an impregnating liquid having the composition shown in Table 2, and one side of the paper was impregnated with the resin liquid. 8 sheets of paper impregnated with resin liquid and copper foil MK with adhesive
-61 (manufactured by Mitsui Kinzoku Mining Co., Ltd.) were stacked on top of each other and placed between two Lumirror films (manufactured by Toray Industries, Ltd., polyester film) and hot pressed using a scissor press. The heat and pressure conditions were 140°C for 10 minutes and a pressure of 10Kg/cm ² .
Thereafter, it was heated in a dryer at 150°C for 1 hour to complete curing. The thickness of the obtained copper-clad laminate is
It was 1.58-1.62mm. An electric circuit was formed on this copper-clad laminate using the etched oil method to produce a printed circuit board. Table 3 shows the measurement results of the electrical characteristics. (Conventional Example 1) A printed circuit board was produced in the same manner as in Example 1, except that an unsaturated polyester resin () to which 2 parts of dibenzoyl peroxide was added was used as the resin composition for a laminate. The measurement results of various properties are shown in Table 3. (Conventional example 2) Commercially available paper phenol laminate (thickness 1.6 mm, XPC
A printed circuit board was produced in the same manner as in Example 1 using the same grade. The measurement results of various properties are shown in Table 3.

【table】

[Table] As is clear from Table 3, the printed circuit board of the example has higher heat resistance than the printed circuit board manufactured using the unsaturated polyester resin shown in Conventional Example 1, and the printed circuit board manufactured using the phenol resin shown in Conventional Example 2 has higher heat resistance. It has better electrical characteristics than conventional printed circuit boards. The methods for measuring the dielectric constant, dielectric loss tangent, insulation resistance, surface resistance, and hot bending modulus in Table 3 were conducted in accordance with JIS C6481. In addition, the comparative tracking index was measured using the IEC method. The measured values of permittivity and dielectric loss tangent are at 1MHz,
The surface resistance shows the value measured on the laminate surface, and the comparative tracking index value shows the value measured on the adhesive surface. Heat resistance was determined by visual inspection of the printed circuit board after immersing it in a solder bath at 260°C for 1 minute. "Effects of the Invention" As explained above, the printed circuit board of the present invention is produced by dissolving an allyl ester resin having an allyl ester group at the end of a polyester made of a polybasic acid and a polyhydric alcohol, and an allyl ester resin. , and a radically polymerizable liquid crosslinkable monomer as essential components, the substrate is impregnated with an impregnating liquid, and the impregnated substrates are laminated to form a laminated board. Therefore, when manufacturing printed circuit boards, printed circuit boards can be manufactured without using the prepreg method.
This makes it possible to reduce costs such as raw material prices and equipment costs, and to manufacture printed circuit boards through simple processes, and the resulting printed circuit boards have excellent heat resistance and electrical properties. . Therefore, the present invention has the effect that a printed circuit board with excellent heat resistance and electrical characteristics can be provided at low cost.

Claims (1)

[Claims] 1 Contains as essential components an allyl ester resin having an allyl ester group at the end of a polyester composed of a polybasic acid and a polyhydric alcohol, and a liquid crosslinking monomer that dissolves the allyl ester resin and is capable of radical polymerization. A printed circuit board characterized by using a laminate board made by impregnating a base material with an impregnating liquid and laminating the impregnated base materials.