JPH0320138B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for producing a paper-based phenolic resin laminate that has excellent punching workability and maintains flame retardancy. Conventional technology Conventionally, in order to impart flame retardancy to paper-based phenolic resin laminates, Br-based compounds (mostly Br-based epoxy resin, tetrabromobisphenol A, Br-based diphenyl ether, etc.) have been added to the phenolic resin. ), P-based compounds (triphenyl phosphate,
(tricresyl phosphate, etc.), N-based compounds (melamine resin, benzoguanamine resin, etc.), antimony trioxide, etc. were used in combination. In addition, in order to further improve flame retardancy, the paper base material is treated in advance with a phenolic resin initial condensate, a melamine resin initial condensate alone, or a water or methanol solution containing a mixture of these, and then an overcoat is applied as described above. There is also a method of using phenolic resin and Br, P, and N compounds. As the phenolic resin, tung oil-based phenolic resin is often used due to recent demands for lowering the punching temperature of laminates and improving punching workability. Problems to be Solved by the Invention In the conventional compounding system, in order to further lower the punching temperature, it is necessary to increase the amount of tung oil-modified phenolic resin used, but the flame retardance decreases. On the other hand, in order to improve flame retardancy, the Br
Increasing the content of P-based compounds, P-based compounds, and N-based compounds leads to a decrease in punching properties due to a decrease in heat resistance and interlayer adhesion, and further to an increase in costs due to differences in material prices. That is, in conventional compounding systems, improving punchability and ensuring flame retardancy have a contradictory relationship, and it has been extremely difficult to achieve both. The object of the present invention is to solve these problems in conventional compounding systems and to provide a paper-based phenolic resin laminate that has both punching workability and flame retardancy. Measures to solve the problem If the paper substrate is pretreated with a phenolic resin precondensate, a melamine resin precondensate, or a mixed solution of both, and then overcoated with tung oil-modified phenolic resin to obtain a laminated material, the overcoat The use of Br-based, P-based, and N-based flame retardants in resins works in the direction of inhibiting the flexibility and interlayer adhesion of tung oil-modified phenol resin, so the amount of the flame retardants used is as much as possible to improve punchability. need to be reduced. As already mentioned, pre-treating the paper base material with a phenolic resin initial condensate or a melamine resin initial condensate alone or in combination is a great way to improve flame retardancy, even if the material does not have any flame retardant action. It is known to be effective. The present invention uses a compound that exhibits a more active flame retardant effect than phenolic resin or melamine resin at the stage of pre-treating (undercoating) the paper base material,
It reduces the amount of flame retardant used in the top coat resin. Br, P, and N are known as elements that have a flame retardant effect, but in order to meet the purpose of the present invention, they must be water-soluble in order to improve the treatment effect on paper base materials. As a result of various selections, the general formula (l, m, n are integers of 1 to 5) An aminomethyl phosphonate represented by the following was selected. To use it, the aminomethyl phosphonate is mixed with a phenolic resin initial condensate, a melamine resin initial condensate, or a mixed solution of both, diluted with water and methanol to a predetermined concentration, and used as an undercoat resin. The amount of aminomethylphosphonate to be added is not particularly limited, but when the solid content of the undercoat resin is 100 parts by weight, 2 to 20% is practically appropriate. If the amount added is small, a sufficient flame retardant effect cannot be obtained, and if it exceeds 20%, the heat resistance of the laminate may be reduced due to the low heat resistance of aminomethylphosphonate itself. In the present invention, after applying the above-mentioned undercoat to the paper base material, a topcoat of tung oil-modified phenolic resin varnish containing a flame retardant is applied to obtain a laminate material, which is then laminated and molded to produce a laminate. Effect By adding a water-soluble aminomethylphosphonate compound, it can be used in the pre-treatment stage of paper base materials in addition to the treatment effects of solvents such as water and methanol, as well as the treatment effects of low-molecular phenol resins and melamine resins. In addition, the P-based compound, which has a positive flame retardant effect, is fixed in the paper base material, thereby increasing the flame retardant effect. This reduces the amount of flame retardant used in the top coat resin, minimizes the drawbacks caused by adding flame retardants, maximizes the advantages of tung oil-modified phenolic resin, and improves punching processability. . Example Phenol resin initial condensate, trimethylolmelamine, diethyl-N,N-bis(2-hydroxyethyl)-aminomethylphosphonate were added in a solid weight ratio of 60/30/10, and concentrated with water and methanol. A resin varnish for undercoat diluted to 15% was prepared. After soaking 11 mils kraft paper in the above resin varnish for undercoating and drying at 160°C for 10 minutes, add tung oil-modified phenolic resin, brominated epoxy resin with an epoxy equivalent of 400 and a Br content of 48%, and triphenyl phosphate. A laminate material with a total resin content of 50% was obtained by impregnating and drying a top coat resin varnish prepared with a solid content weight ratio of 70/20/10. A 35 μm thick copper foil was placed on the surface of the 8 sheets of the laminated material, and this was heated and pressed to obtain a 1.6 mm thick single-sided copper-clad laminate. Comparative Example 1 A phenolic resin initial condensate and trimethylolmelamine were added at a solid weight ratio of 70/30,
A resin varnish for undercoat diluted with water and methanol to a concentration of 15% was prepared. Hereinafter, a single-sided copper-clad laminate with a thickness of 1.6 mm was obtained in the same manner using the same top-coat resin varnish as in the example. Comparative Example 2 Using the same undercoat resin varnish as Comparative Example 1,
After pretreatment in the same manner as in the example, a tung oil-modified phenolic resin, a brominated epoxy resin with an epoxy equivalent of 400 and a Br content of 48%, and triphenyl phosphate were prepared in a solid weight ratio of 50/40/10. Using resin varnish for top coating, in the same manner as in the example below,
A single-sided copper-clad laminate with a thickness of 1.6 mm was obtained. Table 1 shows the characteristics test results of the laminates of Examples and Comparative Examples 1 and 2.

[Table] Effects of the Invention As is clear from Table 1, the laminate according to the present invention has a phenolic resin modified with tung oil as the top coat.
Flame retardancy can be ensured even though the amount of Br-based flame retardant is 50% of the conventional amount, and by increasing the amount of tung oil-modified phenol resin used, it is possible to provide laminates with excellent punchability and reduce costs. It is of great industrial value in that it can also be used to

Claims (1)

[Claims] 1. General formula (l, m, n are integers of 1 to 5) Aminomethyl phosphonate represented by is added to a phenolic resin initial condensate, a melamine resin initial condensate, or a mixed solution of both to prepare a resin varnish for undercoating. A method for producing a laminate board, which comprises pre-impregnating a paper base material, drying it, further impregnating it with a tung oil-modified phenolic resin varnish containing a flame retardant, drying it to obtain a laminate material, and then laminating and molding this material.