JPS5971333A - Resin-impregnated laminated paper board - Google Patents

Abstract

PURPOSE:To obtain the titled laminated board having excellent flameretardance, electrical insulation, strength, and soldering resistance, by impregnating a specific amount of a phenolic resin in a paper sheet composed of specific amounts of Al(OH)3 poweder, inorganic fibers and cellulose pulp, and laminating and forming the impregnated paper sheets. CONSTITUTION:A paper sheet composed of 70-90wt% of Al(OH)3 powder, 1- 10wt% of inorganic fibers and 9-28wt% of cellulose pulp is impregnated with a phenolic resin, and the sheets are laminated and formed to obtain the objective laminated board. The content of the phenolic resin in the laminated board is adjusted to 25-60wt%. The paper may be treated with a silane coupling agent either by treating the Al(OH)3 powder with the agent, or by treating the paper with the agent, or by impregnating the paper with the phenolic resin containing the agent. The amount of the silane coupling agent is preferably 0.05-1wt% based on Al(OH)3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laminate that is excellent in flame retardancy, electrical insulation, strength, and solder heat resistance, and more specifically, it is made from aluminum hydroxide powder, inorganic fibers, and cellulose pulp in a specific ratio. This invention relates to a laminate made by impregnating mixed paper with a phenol resin solution in a specific proportion, laminating and forming the mixture.

Laminated boards, which are made by impregnating paper with phenolic resin and applying heat and pressure, have been used for various electrical insulating materials including printed circuit boards.

However, since the impregnated resin and paper are generally flammable materials, in order to make the laminate nonflammable or flame retardant, flame retardant resins are used or flame retardants are added to the resin liquid. There is.

However, these flame retardant resins and flame retardants contain elements such as halogen, antimony, and phosphorus, are often toxic, and are expensive, and the chemical resistance, heat resistance, and electrical properties of the cured resins are limited. It has the disadvantage that it causes a decrease in

On the other hand, the present inventors used aluminum hydroxide at 55 to 9
We have discovered that by using paper mixed with pulp in the range of 5% by weight as the base paper for laminates, flame retardancy and electrical properties are significantly improved compared to laminates using conventional paper. Taku patent application 0156-58401).

This laminate was found to have excellent flame retardancy and electrical properties, but as a result of further research, the inventors and others
Aluminum hydroxide powder 70-90% by weight, inorganic fabric 11
A mixed paper consisting of 1 to 10% by weight of cellulose pulp and 9 to 28% by weight of cellulose pulp is impregnated with phenolic resin, laminated and molded to form a laminate, and the phenolic resin content in the laminate at this time is calculated based on the weight of the laminate. It has been found that by adjusting the content to 25 to 60%, a laminate with even better properties such as strength, flame retardance, electrical properties, and solder heat resistance can be obtained. .

The aluminum hydroxide powder used in the present invention is
It may have a givenite crystal structure, a boehmei]-crystal structure, or a bayerite crystal structure, but in consideration of the thermal decomposition temperature, it is desirable to have a gibbsite crystal structure. Further, the average particle diameter is preferably 100 microns or less, particularly 0.5 microns or less.
~60 microns is optimal.

Inorganic fibers include glass fiber, slag wool,
Rock wool, asbestos fibers, etc. can be used.

As the cellulose pulp, natural cellulose pulp such as paper pulp can be preferably used, but in order to increase the amount of aluminum hydroxide, which has a negative potential, fixed on the pulp, it is preferable to use a cationically modified pulp obtained by cationizing the pulp. In addition, without cationizing the pulp,
The constant Wl of aluminum hydroxide to pulp can also be increased by positively charging the atmosphere of the aqueous dispersion of pulp and aluminum hydroxide using a thionized resin or the like.

The phenolic resin to be impregnated into the mixed paper is prepared by reacting phenols such as phenol, cresol, resorcinol, or alkyl-substituted phenol with formaldehyde or paraformaldehyde using an alkaline substance as a catalyst, or by reacting an acidic reaction with an alkaline substance. Liquid resins obtained by the process, oil-modified phenolic resins, melamine-modified phenolic resins, etc. can be used, and these resins are generally dissolved in a solvent such as methanol or acetone and impregnated into the mixed paper.

The method for manufacturing the laminate of the present invention will be explained below.

After adding No. 11 Hi cloth to the beaten pulp slurry and mixing well, a cationizing agent such as polyamide epichlorohydrin resin is added to cationize the pulp fibers. Next, a slurry of aluminum hydroxide powder having a particle size of 0.5 to 60 microns dispersed in water is added, thoroughly mixed, and paper is made using a paper machine. At this time, the ratio of aluminum hydroxide powder, inorganic fiber and pulp is 70-90:1-10:
9 to 28 (all percentages by weight).

The thus obtained mixed paper is immersed in a phenolic resin solvent solution and tied, and impregnated so that the phenol resin content when formed into a laminate becomes 25 to 60% (in terms of solid content) of the laminate weight.

This impregnated paper is dried to evaporate the solvent, and a predetermined number of sheets are piled up and heated at 90 to 120° C. for 5 to 30 minutes. This causes the impregnated phenolic resin to condense and become B-stage. After that, at roughly 120-180℃, 10-2
The laminate of the present invention can be manufactured by proceeding with condensation under a pressure of 0.00 k (+/ci2), curing and shaping.

The blending ratio of aluminum hydroxide powder, inorganic fiber, and cellulose pulp in the mixed paper used in the present invention is 70 to 90:1.
The reason why the ratio was limited to 10:9 to 28% by weight) is as follows. That is, when the content of aluminum hydroxide powder is lower than 70% by weight, flame retardancy becomes insufficient,
If it exceeds 90% by weight, bending strength becomes insufficient and solder heat resistance decreases. Komoda, nothing (fiber content is 1% by weight)
If the bending strength is lower than 10M%, the bending strength will be insufficient.
Even if the bending strength is exceeded, the bending strength will be insufficient. This seems to be related to the relationship between w<wei. If the content of cellulose pulp is lower than 9% by weight, the bending strength will be insufficient, and if it exceeds 28% by weight, the flame retardance will be insufficient.

The phenolic resin content in the laminate is 25 to 60% by weight (
The reason for this is that if the content is lower than 25% by weight, the bending strength of the laminate increases by 1q, but the laminate becomes non-uniform, and conversely, if it exceeds 60% by weight, it becomes flame retardant. This is because they become less sexually active.

Note that by treating the laminate of the present invention with a silane coupling agent, the bending strength and solder heat resistance of the laminate can be further improved. As the silane coupling agent, aminosilane, boxysilane, vinylsilane, etc. can be used. Methods for treating the laminate with a silane coupling agent include a method in which mixed paper is manufactured using aluminum hydroxide powder that has been treated with a silane coupling agent in advance, a method in which mixed paper is treated with a silane coupling agent, and a method in which mixed paper is treated with a silane coupling agent. Any method, such as a method of impregnating mixed paper with a phenolic resin containing an agent, can be adopted. The amount of the silane coupling agent used is 0.01 to 5% by weight, preferably 0.05 to 1% by weight based on aluminum hydroxide.
If the amount of the coupling agent is less than this, the processing effect will be poor, and if it is more than this, no improvement in performance can be expected and the cost will increase.

The features of the present invention will be further explained below with reference to Examples and Comparative Examples.

Aluminum hydroxide powder (Showa Light Metal Co., Ltd., Taisei, Hisilite H-32) with an average particle size of about 8 microns was gradually added to water with stirring to create an aqueous dispersion with a solid content of 10% by weight. Separately, softwood was bleached. Kraft pulp (beating degree 35
After adding a predetermined amount of glass fiber (10 microns in thickness, 3++1 m in length) to a 3% by weight aqueous dispersion of SR) and thoroughly mixing the mixture, a modified polyacrylamide resin was added to make the atmosphere of the aqueous dispersion cationic. It became.

The pulp thus obtained and the aqueous dispersion of glass [E] were mixed with the aqueous dispersion of aluminum hydroxide in a predetermined amount, and paper was made using a Fourdrinier paper machine to make a mixed paper with a basis weight of 190(]/T112). In this case, the ratios of pulp, aluminum hydroxide powder, and glass fiber were changed to produce mixed papers with various blending ratios.

Phenol resin (manufactured by Showa Union Gosei Co., Ltd.,
BLSA-3122) was impregnated with a varnish diluted with methanol and squeezed with a squeezing roll. The amount of resin impregnated was adjusted by the methanol dilution rate and squeezing pressure. impregnation t
The phenol resin was dried for 10 minutes at aioo''C to evaporate the solvent (this phenolic resin was made into a B stage). Eight sheets of this impregnated paper were stacked at 100k (160 kg) under a pressure of 1/C1N2.
It was pressed for 60 minutes at ℃. The cooled inlet was cooled to room temperature and the pressure was removed to produce a laminate.

In addition, when performing the silane coupling agent treatment, a predetermined amount of the silane coupling agent was applied to a varnish prepared by diluting a phenol resin with methanol, and the mixed paper was impregnated with this varnish.

The physical properties of various laminates manufactured by changing the blending ratio of mixed paper pulp, aluminum hydroxide powder, and glass fiber and changing the amount of phenol resin impregnated were determined according to JIS K-6.
Table 1 shows the results of measurements based on 911 and UL standard test methods.

From this Table 1, it can be seen that the laminates having compositions within the range of the present invention, such as Examples 1 to 7, have the same physical properties as those of Comparative Examples 1 to 5, such as flame retardancy, electrical insulation, strength, and soldering heat resistance. It can be seen that the composition is superior to those with compositions outside the range of .

In particular, it can be seen that by applying the silane coupling agent treatment as in Examples 2.3, 5.6, and 7, the bending strength and solder heat resistance of the laminate are further improved.

Example 8 Aluminum hydroxide powder (manufactured by Showa Light Metal ■, Hisilite 1''-32) with an average particle size of about 8μ was gradually added to water with stirring to make an aqueous dispersion with a solid content of 12% by weight. 10% aqueous solution of propylaminotriethoxysilane per 100 parts by weight of the dispersion? Add 0.5 parts by weight of rg and stir to sufficiently adsorb the coupling agent to the aluminum hydroxide. Separately, Kenkaju bleached kraft pulp (beating degree 35)
An aqueous dispersion containing 3% by weight of SR) and 0.5% by weight of glass fibers having a thickness of 10μ and a length of 3n1m is prepared, and a modified polyacrylamide resin is added to cationize the atmosphere of the aqueous dispersion. This pulp and one glass fiber dispersion were mixed with an equal amount of the aluminum hydroxide dispersion, and paper was made using a Fourdrinier paper machine to make a mixed paper having a basis weight of 210 g/ff. As a result of analysis, the components of this mixed paper were 79% by weight of aluminum hydroxide, 18% by weight of pulp, and 3% by weight of glass fiber.

This mixed paper was impregnated with the same phenolic resin as in Examples 1 to 7 under the same conditions and pressed under the same conditions to produce a laminate. The phenolic resin content of the laminate was 31% by weight.

As a result of measuring this laminate based on JIS K-6911 and UL standard test method, the bending strength was 15 kg/Im'
, surface resistance before boiling: 1oゝΩ, surface resistance after boiling for 24 hours: 10Ω, passed V-O with IJL standard flame retardant test soap,
An excellent result of solder heat resistance of 12 seconds was obtained.

Patent applicant: Showa Denko Co., Ltd. Same Toyo Pulp Co., Ltd. Nippon Steel Mining Co., Ltd.

Claims (1)

[Scope of Claims] F. A mixed paper consisting of 70 to 90% by weight of aluminum hydroxide powder, 1 to 10% by weight of inorganic fibers, and 9 to 28% by weight of cellulose pulp is impregnated with a phenolic resin and laminated;
1. A 1 m laminate of resin-impregnated paper, which is a molded laminate, characterized in that the phenolic resin content in the laminate is 25 to 60% of the weight of the laminate. 2. A mixed paper consisting of 70-90% by weight of aluminum hydroxide powder, 1-10% by weight of inorganic fibers and 9-28% by weight of cellulose pulp is impregnated with phenolic resin and laminated;
A laminate formed by molding, characterized in that the phenolic resin content in the laminate is 25 to 60% of the weight of the laminate, and the laminate is treated with a silane coupling agent. Resin-impregnated paper laminate.