JPH0244330B2 - FUENOORUFUOOMUNOSEIZOHOHO - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a phenolic foam using a benzyl ether type phenolic resin. Phenol foam is known for its heat resistance, flame retardancy,
Although it has excellent performance such as low smoke emission, it is difficult to use because it is extremely brittle and has a tendency to fall apart compared to other plastic foams such as urethane foam and polystyrene foam. In addition to these physical property disadvantages, resol-type phenolic resins have problems with their own storage stability, and novolac-type phenolic resins have their own disadvantages, such as being inconvenient to handle because they are solids. However, up to the present, the amount of phenol foam used has not increased significantly. On the other hand, in the case of phenol foam made from a benzylic ether type phenolic resin, the phenol resin itself has good storage stability, but when a curing agent is added, it turns into a resin with intense heat generation and foaming. The resulting foam has a very low density and is too brittle to be used as an insulating material. Regarding foams using benzylic ether type phenolic resin, a method of producing urethane foam by reacting with a polyisocyanate compound is also known, for example, in Japanese Patent Publication No. 55-27093, etc.
Compared to phenol foam, it is considerably inferior in terms of flame retardancy, low smoke emission, etc. The present invention uses a practically applicable benzyl ether type phenolic resin that maintains the heat resistance, flame retardance, and low smoke emission properties that are the characteristics of phenol foam, while improving the poor mechanical properties that are its drawbacks. It concerns the phenol form. That is, the present invention provides a method for producing phenol foam, which comprises foaming and heating a liquid mixture consisting of a benzyl ether type phenolic resin, a polyisocyanate compound, an aromatic sulfonic acid compound, water, a blowing agent, and a foam stabilizer. It is. Since the phenol foam according to the present invention has a hard skin layer and does not have any slipping properties, it has good adhesion to the surface material, which was not possible with conventional phenol foams made from resol type or novolac type phenolic resins. It also has the advantage that a laminate with various surface materials can be integrally molded by self-adhesion. The benzyl ether type phenol resin used in the present invention is known from, for example, Japanese Patent Publication No. 47-50873, and has the general formula

[Formula] (R represents a hydrogen atom, a hydrocarbon group, an oxyhydrocarbon group, or a halogen atom. n = 1-3) and the following general formula R'CHO (R' is a hydrogen atom or 1-3) (representing a hydrocarbon group having 8 carbon atoms) in a ratio of 1:1 to 1:3 in the presence of a metal salt catalyst. The foam stabilizer used in the present invention is a silicone nonionic surfactant and/or a nonionic surfactant, such as an ethylene oxide adduct of sorbitan fatty acid ester, alkylphenol, or the like. The blowing agent used in the present invention is a low-boiling aliphatic hydrocarbon or its halide, and examples thereof include petroleum ether, n-hexane, n-heptane, methylene chloride, and trichlorofluoromethane. The aromatic sulfonic acid compound used in the present invention is typified by benzenesulfonic acid, toluenesulfonic acid, xylene sulfonic acid, phenolsulfonic acid, etc., but inorganic acids such as phosphoric acid, sulfuric acid, and hydrochloric acid can also be used in combination. The aromatic sulfonic acid compound is preferably used as an aqueous solution with an appropriate amount of water. The addition of water used in the present invention can be accomplished by any method, such as by using an aromatic sulfonic acid as an aqueous solution as described above. The amount of water is effective if it is in the range of 0.1 to 100 parts by weight, preferably 4 to 45 parts by weight, based on 100 parts by weight of the benzyl ether type phenolic resin. Excessive water in excess of 100 parts by weight will cause bulging, while less than 0.1 part by weight will result in uncontrollable foaming. The polyisocyanate compound used in the present invention is
Polymethylene polyphenyl isocyanate (so-called crude 4,4'-diphenylmethane diisocyanate), tolylene diisocyanate, hexamethylene diisocyanate, etc. are preferred, but reactions of polyisocyanates with polyhydric alcohols such as glycol, glycerin, and trimethylolpropane are preferred. A polyisocyanate compound having a terminal isocyanate group or a prepolymer type polyisocyanate compound having a terminal isocyanate group obtained by reacting a polyisocyanate with a polyether-based or polyester-based polyol can also be used. The polyisocyanate compound and the aromatic sulfonic acid compound have an [NCO]/[SO ₃ H] equivalent ratio of 0.0 to 1.0,
It is preferably used in a range of 0.3 to 0.9. ([NCO] here refers to the gram equivalent of isocyanate groups, and [SO ₃ H] refers to the gram equivalent of sulfone groups.) [NCO]/[SO ₃ H] equivalent ratio of 0.1 or less In this case, the resulting foam is very brittle, has a low density, and has a large shrinkage after molding. If the [NCO]/[SO ₃ H] equivalent ratio exceeds 1.0, the foam will be extremely non-uniform and a practical foam cannot be obtained. The polyisocyanate compound is 1 to 50 parts by weight per 100 parts by weight of benzyl ether type phenol resin.
Parts by weight may be used, preferably in the range from 3 to 25 parts by weight. The amount of the foam stabilizer used is preferably 1 to 5 parts by weight per 100 parts by weight of the benzyl ether type phenolic resin. In the present invention, in order to further improve the mechanical properties of the foam, as additives, polyhydric hydroxy compounds such as ethylene glycol, propylene glycol, glycerin, or polyoxyalkylene polyols such as polyoxyethylene glycol, It is also possible to add polyoxypropylene glycol or nitrogen-containing compounds such as diethanolamine, triethanolamine, diethanoltriamine, urea, etc.Flame retardants can also be added to further improve heat resistance, flame retardancy, and low smoke emission. , inorganic powder, etc. can be added as appropriate. The foam according to the invention is produced as follows. A benzyl ether type phenolic resin, a foam stabilizer, a blowing agent, and optionally other additives are mixed. Next, a polyisocyanate compound and an aromatic sulfonic acid compound are added to this liquid mixture, mixed vigorously at room temperature, poured into a mold, and heated to 60 to 80°C to obtain a foam. In this case, although it takes some time, a foam can be obtained without heating.
It is also possible to mix the polyisocyanate compound and the curing agent in advance and add them to the above mixture. Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. Example 1 Prior to foam molding, a benzyl ether type phenolic resin was synthesized by the following method. Phenol 357g, paraformaldehyde 174
g, 1.5 g of lead naphthenate, and 3.0 g of zinc naphthenate were stirred and mixed, and after reacting at 110 to 114°C for 3 hours, they were immediately dehydrated under reduced pressure.
A benzyl ether type phenolic resin of 30,000 cps (at 25°C) was obtained. Example 2 100 g of benzyl ether type phenol resin obtained in Example 1, 3 g of foam stabilizer (Tween-40:
(Manufactured by Kao Atlas Co., Ltd.), 25g of foaming agent (Freon R-
11:Mitsui Fluorochemical Co., Ltd.) mixed thoroughly,
Add to this 70g of hardening agent (p-toluenesulfonic acid 70%)
Aqueous solution) and 4.0 g of crude diphenylmethane diisocyanate (Millionate MR-200: manufactured by Nippon Polyurethane Co., Ltd.) were added and mixed using a lab mixer.
After stirring vigorously for 15 seconds at 3,000 to 4,000 rpm, the mixture was poured into another mold for foaming. The foam obtained after heating the foam in a constant temperature bath at 60 to 80°C for 30 to 60 minutes had no brittleness, no looseness, no shrinkage, and had good mechanical properties. Table 1 shows the physical properties of the phenol foam obtained in this example, and the results of the flame retardancy test (ASTM-D-1692) and smoke generation test (JIS A-1321).

[Table]
Examples 3 to 10 and Comparative Examples 1 to 3 Using the benzyl ether type phenolic resin described in Example 1, foams were synthesized in the same manner as in Example 2. The compounding recipe and molding results are shown in Table-2. (The numbers in the table represent parts by weight.)

【table】

【table】

[Table] As described above, in Examples 2 to 10, good foams were obtained that were free from brittleness, looseness, and shrinkage. Example 11 In order to demonstrate that the phenol foam according to the present invention has excellent adhesion to face materials, the adhesive strength with K-liner paper and mild steel plate was measured by a 90 degree peel test. For comparison, Table 3 shows the results of the same test for phenol foam obtained from resol type phenolic resin.

【table】

[Table] The adhesive strength of the phenol foam according to the present invention to the surface material was 6 to 9 times higher than that of the phenol foam using a resol type phenolic resin.

Claims (1)

[Claims] 1. A method for producing phenol foam, which comprises foaming and heating a liquid mixture consisting of a benzyl ether type phenolic resin, a polyisocyanate compound, an aromatic sulfonic acid compound, water, a foaming agent, and a foam stabilizer.