JPH04355123A - Manufacture of phenolic resin laminated sheet - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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 phenolic resin laminate used as an electrical insulating board.

0002

[Prior Art] Recently, insulating materials, especially laminates and copper-clad laminates used for communication equipment and electronic equipment, are being punched at room temperature or a relatively low temperature near room temperature from the viewpoint of automation of processing equipment and energy saving. Excellent properties are required. For this reason, phenol-formaldehyde resins modified with drying oil or the like are usually used as resins for laminates, in which various alkylphenols are used in combination with phenol.

However, phenol-formaldehyde resins modified with drying oil have a slow curing speed and lower crosslinking density due to the modification with drying oil, so the resin in the laminate tends to be insufficiently cured, resulting in poor heat resistance and mechanical properties. Properties such as strength and water resistance deteriorate. Furthermore, during punching, interlayer peeling is likely to occur due to the low crosslinking density. In other words, in the conventional drying oil-phenol reaction products, the number of moles of phenol added to the drying oil is low, and since a polymer of drying oil is produced, the reaction rate is low in the reaction with formaldehyde, that is, the resinization reaction and curing reaction. And the curing speed was decreased, causing deterioration of various properties.

[0004] As a method for improving the curing property, there is a method in which a reaction product obtained by reacting phenols and formaldehyde in the presence of an acid catalyst is added to a dry oil-modified phenol/formaldehyde resin (Japanese Patent Application Laid-open No. 121932/1982). Proposed. Although this method shows some improvement in hardenability, it is still not sufficient to meet the recent demands for laminates in terms of punching workability, toughness, etc.

Furthermore, a method has been proposed in which cyclopentadiene or dicyclopentadiene-modified phenolic resin is used as a varnish for laminates (Japanese Patent Publication No. 47-6733). However, even in the case of this method, various properties such as punching workability and toughness are still not satisfactory. The reason for this is thought to be that it contains many components that are extremely unlikely to participate in the curing reaction, thereby reducing curability.

[0006] Recently, as printed wiring boards have become increasingly dense, there is a need to improve dimensional accuracy, and as a result, laminates have been developed that are superior in punching workability at low temperatures and toughness capable of withstanding the mounting of heavy components. It has been difficult to achieve both of these characteristics using conventional methods.

[0007]

Problems to be Solved by the Invention The present invention was developed as a result of research aimed at obtaining a phenolic resin laminate having punching workability and toughness that cannot be obtained by conventional methods. We have found that a laminate using a resin component in which resol type DCPD modified phenolic resin (hereinafter abbreviated as resol type DCPD modified phenol resin) is added to dry oil modified phenol/formaldehyde resin has extremely excellent punching workability and toughness, and based on this knowledge, we have developed various This was completed through research. The purpose is to provide an extremely tough phenolic resin laminate with excellent punching workability, water resistance, electrical properties, and mechanical properties, and a method for producing the same.

[0008]

[Means for Solving the Problems] The present invention provides resol type D
A resin component in which 3 to 50 parts by weight of CPD-modified phenol resin is added to 100 parts by weight of dry oil-modified phenol/formaldehyde resin is impregnated into a base material for a laminate, dried, and then laminated. The present invention relates to a method for manufacturing a phenolic resin laminate.

[0009] Resol type DC used in the present invention
PD-modified phenolic resin is produced by synthesizing a phenol/DCPD polymer through the reaction of phenols and dicyclopentadiene (hereinafter abbreviated as DCPD), and from the phenol/DCPD polymer.
It is most preferably produced by a two-step resolization reaction of a DCPD polymer with aldehydes.

[0010] The phenol/DCPD polymer is produced by adding an acid catalyst dropwise to a mixture of phenols and DCPD.
A method of reacting at a predetermined temperature of 0°C for a predetermined time, or a method of dropping DCPD over a predetermined time while maintaining a mixture of phenols and an acid catalyst at a predetermined temperature of 20 to 170°C, and further reacting for a predetermined time if necessary, etc. Can be synthesized. At this time, the reaction mixture contains a phenol/DCPD polymer represented by formula (I), a phenol/DCPD polymer containing an ether bond,
It contains the DCPD reactant (II), a homopolymer of DCPD, and unreacted phenols.

[0011]

[Chemical formula 1]

0012

[Case 2]

[0013] Also, in DCPD, at high temperatures, the equilibrium between DCPD and cyclopentadiene (hereinafter abbreviated as CPD) leans toward CPD, so depending on the reaction conditions, phenol/CPD polymers, phenol/CPD reactants containing ether bonds, CP
A homopolymer of D is also produced. These compositions can be changed significantly depending on the type and amount of acid catalyst, reaction temperature, and reaction time.

If necessary, the reaction mixture is neutralized with a basic substance or washed with water to remove the acid catalyst, and if necessary, unreacted phenols are removed by distillation under reduced pressure under heating for the next resolization reaction. served. At this time, it is preferable not to contain 20% or more of unreacted phenols. If 20% or more of unreacted phenols remain, they will react with aldehydes in the subsequent resolization reaction to produce a resol-type phenolic resin that is not modified with DCPD, resulting in a decrease in the DCPD modification rate and insufficient punching. Workability and toughness cannot be obtained.

As the phenols, phenol or substituted phenols having an alkyl group or aryl group having 1 to 9 carbon atoms as a substituent can be used.
Phenol, o-cresol, m-cresol, p-cresol, 3,5-xylenol, 2,4-xylenol, butylphenol, octylphenol, nonylphenol, phenylphenol are preferred, especially:
Phenol and m-cresol are preferred. It is also possible to use two or more types of phenols in combination. The reaction molar ratio of phenols/DCPD varies depending on the catalyst species, catalyst amount, reaction temperature, reaction time, etc., but is preferably from 1/1 to 7/1, and more preferably from 3/1 to 5/1. When the reaction molar ratio of phenols/DCPD is 1/1 or less, D
A large amount of CPD homopolymer is produced, resulting in a decrease in curability. Also, if it exceeds 7/1, the phenol/D
The degree of polymerization of the CPD polymer decreases, and the curability decreases. Examples of acid catalysts include inorganic acids such as boron trifluoride, hydrochloric acid, sulfuric acid, phosphoric acid, phosphoric anhydride, zinc chloride, ferric chloride, and aluminum chloride; organic acids such as oxalic acid, acetic acid, and p-toluenesulfonic acid; Others may be used alone or in combination. The amount of the catalyst used is not particularly limited, but is preferably 0.01 to 5% by weight based on the amount of phenols charged. As basic substances for neutralization, ammonia, triethylamine,
Amines such as triethanolamine and hexamethylenetetramine, and alkali metal hydroxides such as sodium hydroxide and potassium hydroxide are used, but when alkali metal hydroxides are used, ionic substances are contained in the reaction product. Ammonia and amines are preferably used since the residual electrical properties are deteriorated.

[0016] The resol type DCPD-modified phenol resin is produced by combining the phenol/DCPD reaction mixture obtained in the first stage reaction with aldehydes such as formalin and paraformaldehyde at a predetermined temperature of 40 to 120°C in the presence of a basic catalyst. It can be obtained by diluting with an organic solvent such as methanol or toluene. Organic solvents such as alcohols such as methanol, ethanol, propanol, and butanol, aromatic hydrocarbons such as benzene, toluene, and xylene, and ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone may be used as the reaction solvent.

The amount of aldehydes to be added is determined based on 1 mole of phenol charged in the first stage reaction, or when unreacted phenol is removed after the reaction, 1 mole of phenol nucleus in the reaction mixture after removal of unreacted phenol. 0 per mole.
1 to 2.0 mol is preferable, and 0.6 to 1.4 mol is more preferable. As the basic catalyst, amines such as ammonia, triethylamine, ethylenediamine, hexamethylenetetramine, and triethanolamine, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, barium hydroxide, etc. can be used, but the reaction product Ammonia and amines are preferably used because they do not leave ionic substances in the product.

The drying oil-modified phenol/formaldehyde resin can be synthesized by reacting a drying oil such as tung oil with a phenol in the presence of an acid catalyst, and then reacting it with formaldehyde in the presence of a basic catalyst to form a resol.

The laminate of the present invention is prepared by adding and dissolving the resol-type DCPD-modified phenol resin obtained as described above in a drying oil-modified phenol/formaldehyde resin to obtain a varnish, which can be used to prepare varnishes such as kraft paper, linter paper, glass cloth, glass nonwoven fabric, The laminate of the present invention can be obtained by impregnating and drying a base material such as polyester cloth, aramid fiber cloth, or canvas, and then laminating usually 3 to 10 sheets and molding them under heat and pressure.

The amount of the resol type DCPD modified phenol resin added to both the drying oil-modified phenol/formaldehyde resin is 3 to 50 parts by weight per 100 parts by weight of the drying oil-modified phenol/formaldehyde resin.
Preferably it is 8 to 35 parts by weight. If it is less than 3 parts by weight, there will be little effect of improving hardenability, and if it exceeds 50 parts by weight, punching workability will deteriorate. In addition, the amount of resin to be impregnated is 30 to 7 on a dry basis based on the total amount of resin and base material.
It is 0% by weight. The heating and pressurizing conditions are 120 to 180
The temperature is 50-150 kg/cm2.

[0021] In the present invention, other phenolic resins may be appropriately used in combination with up to 50% by weight of the total resin as the resin to be impregnated into the base material. Examples of resins that can be used in combination include unmodified resol resins and alkylphenol resol resins.

[0022]

[Function] The phenolic resin laminate of the present invention has extremely excellent punching workability, water resistance, electrical properties, and mechanical properties, and can be suitably used for printed wiring boards. The reason why the phenolic resin laminate according to the present invention has extremely improved water resistance and punching workability compared to a laminate using DCPD-modified phenolic resin or drying oil-modified phenolic resin alone is not fully clear. Resol type DCPD
The reaction between the modified phenolic resin and the drying oil-modified phenolic resin occurs extremely quickly compared to the reaction between resol type DCPD modified phenolic resins and the reaction between drying oil-modified phenolic resins, resulting in a laminated layer with a high degree of hardening. This is thought to be due to the fact that the board can be obtained.

The reason why the reaction between the resol-type DCPD-modified phenolic resin and the drying oil-modified phenolic resin is rapid is considered to be due to the following reason. In the reaction between drying oil-modified phenolic resins, since the number of moles of phenol added to the drying oil is low, a polymer of the drying oil is produced during the curing process, which inhibits curing. Furthermore, in the reaction between DCPD-modified phenol resins, since the phenol nuclei have a cyclic structure, when the molecular weight increases to a certain extent during the curing process, the molecular structure becomes rigid, making it difficult for the curing reaction to proceed any further.

On the other hand, as in the present invention, resol type DCPD
When the modified phenolic resin and the drying oil-modified phenolic resin coexist, the number of moles of phenol to the drying oil increases, suppressing the formation of polymers in the drying oil, and furthermore, the resol type DCPD modified phenolic resin and the drying oil-modified phenolic resin The reaction product has a more flexible molecular structure than the reaction product between DCPD-modified phenol resins due to the introduction of the long-chain alkyl group of the drying oil between the phenol nuclei, making it easier to proceed to the next curing reaction. . As a result, it is thought that a laminate that cures quickly and has a high degree of curing can be obtained.

[0025]

[Examples] The present invention will be explained below with reference to Examples.

(Synthesis Example 1) 3008 parts of phenol and 30 parts of para-toluenesulfonic acid were charged into a 51-inch four-necked flask equipped with a thermometer, reflux condenser, stirrer, and dropping funnel, and heated to 140°C. 1056 copies of DCPD
is added dropwise over 4 hours at a temperature of 140±5°C. After the dropwise addition is completed, the mixture is allowed to react at the same temperature for 3 hours. After completion of this reaction, the amount of unreacted phenol was 52.4%. After cooling, 16.8 parts of triethylamine is added to neutralize. At this time, the pH of the solution mixed at a weight ratio of reaction mixture/acetone/water = 1/2/4 was measured and found to be 7.8 (25°C). After neutralization, unreacted phenol is removed by heating under reduced pressure until the internal temperature reaches 150°C. At this time, the amount of unreacted phenol in the reaction mixture was 5.3%. Next, 736 parts of toluene was added and the mixture was cooled to 60° C., and then 21.9 parts of triethylamine was added and mixed with stirring for 10 minutes. At this time, the pH of the solution mixed at a weight ratio of reaction mixture/acetone/water = 1/2/4 was measured and found to be 9.8 (25°C). Next, 419.3 parts of 87% paraformaldehyde was added, and the temperature was gradually raised while removing condensed water produced by the reaction from the system. After reacting at 95 to 100°C for 5 hours, 1051 parts of toluene and methanol were added. 731 parts were added and dissolved to obtain a resol type DCPD modified phenol resin (Resin 1).

(Synthesis Example 2) A mixture of 1200 g of phenol, 800 g of tung oil, and 5 g of p-toluenesulfonic acid was
The reaction was carried out at ℃ for 3 hours. Next, add 800g of toluene to this.
After dilution and neutralization by adding 20 g of triethanolamine, 500 g of paraformaldehyde and 30 g of 25% aqueous ammonia were added, and the mixture was reacted at 90 to 100°C for 4 hours.
Next, dehydration and toluene removal were performed under reduced pressure to obtain toluene 1
000 g and methanol 1000 g were added to dilute the mixture to obtain a tung oil-modified phenol/formaldehyde resin (resin 2) with a resin content of 50% by weight.

(Synthesis Example 3) Phenol 1000g, 37
% formalin and 20 g of triethylamine were mixed and reacted at 60°C for 2 hours, then concentrated under reduced pressure, and diluted with a mixed solvent of methanol/water = 80/20 to obtain a water-soluble, low resin content of 50% by weight. A molecular phenol-formaldehyde resin (resin 3) was obtained.

[Examples and Comparative Examples] Resin 3 obtained in Synthesis Example 3 was impregnated into kraft paper and dried, resulting in a resin content of 10.
A 5% treated substrate was obtained. Next, this treated base material was impregnated with separately prepared top varnishes (Resin 1 and Resin 2) according to the formulations shown in Table 1 and dried to obtain a prepreg with a total resin content of 56%. Eight sheets of this were laminated, a 35 μm copper foil was placed on one side, and the sheets were heated and pressed at 160° C. and 80 kg/cm 2 for 60 minutes to obtain a phenol resin laminate with a thickness of 1.6 mm. Table 1 shows the characteristics of the laminates obtained in Examples and Comparative Examples.

[0030]

[Table 1]

[0031]

Effects of the Invention As is clear from the results in Table 1, the phenolic resin laminate manufactured by the manufacturing method of the present invention has excellent hardening properties, good punching workability, water resistance, electrical properties, mechanical properties, and printability. It can be suitably used for wiring boards.

Claims (2)

[Claims] Claim 1: A resin component in which 3 to 50 parts by weight of a resol-type dicyclopentadiene-modified phenol resin is added to 100 parts by weight of a dry oil-modified phenol/formaldehyde resin is impregnated into a base material for a laminate and dried, followed by laminate molding. A method for producing a phenolic resin laminate, characterized by: [Claim 2] The resol-type dicyclopentadiene-modified phenol resin is synthesized by resole-forming a phenol/dicyclopentadiene polymer that does not contain 20% or more of unreacted phenols.
The method for producing the described phenolic resin laminate.