JPS6121268B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to rubber adhesive compositions. Rubber adhesives are widely used as industrial adhesives, and are used, for example, to bond shoes, woodworking, home appliances, and the like. It is known that alkylphenol resins are added to rubber adhesives in order to improve adhesive retention time, etc., and in such rubber adhesives, it is difficult to attach shoes and when the adhesive is used. When using melamine decorative boards, it is required to improve heat resistance. The heat resistance of conventional rubber adhesives containing alkyl phenol resins can be improved by selecting the amount of the alkyl phenol resin, the type of rubber, the kneading method, etc.; however, in most cases, the adhesive Retention time becomes extremely short. The present invention solves these problems and provides a rubber adhesive composition with improved heat resistance without extremely shortening the adhesive retention time. The adhesive composition has excellent adhesive strength and does not undergo phase separation during storage. That is, the present invention provides: (a) rubber (b) 1 mol or more of aldehyde is heated to react with 1 mol of alkylphenol or arylphenol in the presence of a potassium compound exhibiting basicity, and then acidified and subjected to a condensation reaction. The present invention relates to a rubber adhesive composition comprising a phenolic resin having a softening point of 70 to 100°C obtained by the above process, and (c) a metal oxide. The rubber of the present invention can generally be used in rubber adhesives, such as natural rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, chloroprene rubber, recycled rubber, urethane rubber, epichlorohydrin rubber, etc. It also includes modified versions of these. The phenolic resin of the present invention is produced as follows. That is, 1 mol or more of aldehyde per 1 mol of alkyl or alkylphenol,
Preferably, 1.5 to 3.0 mol of a potassium compound exhibiting basicity is present, preferably 0.01 to 0.5 mol, per 1 mol of the above-mentioned phenol, and the addition reaction is carried out at, for example, 50 to 100°C for about 1 to 10 hours. Then, add organic acid or inorganic acid to 1 mole of the above phenol.
The reaction system is made acidic (preferably pH 1 to 6) by adding 0.03 to 1 mol, and the potassium compound is neutralized. After this, the generated salt is removed by filtering, washing with water, etc., or without being removed, it is subjected to a condensation reaction under acidic conditions (PH of 1 to 6 is preferable), for example, at 80 to 250°C for 5 minutes to 15 hours. It is a resin with a softening point of 70 to 100°C. The phenolic resin thus obtained has a high proportion of aromatic nuclei having two methylol groups, and this is thought to improve heat resistance in the present invention without reducing adhesive retention. . In addition, for this purpose, in the above addition reaction, the amount of potassium compound added must be reduced to 1 phenol.
0.05-0.1 mole to mole, reaction temperature 60-100
The temperature reaction time is preferably 2 to 5 hours. In this case, the proportion of dimethylol phenyl nuclei is approximately 70 to 90% of the total phenyl nuclei. Conventionally, it is known that alkyl or aryl phenol resins produced industrially use alkali metal or alkaline earth metal hydroxides, amines, etc. as addition reaction catalysts in their production. Among these, sodium hydroxide, calcium hydroxide, and barium hydroxide are mainly used. On the other hand, in the production of the alkyl or aryl phenol resin of the present invention, a potassium compound exhibiting basicity, which has almost never been used industrially, is used. In particular, no example of using such a phenolic resin as a compounding agent for a rubber adhesive has been reported to date. Examples of the above-mentioned potassium compounds exhibiting basicity include potassium, potassium hydroxide, potassium oxide, potassium peroxide, potassium tertiary butoxide,
Potassium bromide, potassium bicarbonate, etc. Among these, potassium oxide, potassium hydroxide, potassium tertiary butoxide and potassium peroxide are preferred from the viewpoint of reactivity. The above alkylphenols include cresol, amylphenol, tert-butylphenol, sec-
These include butylphenol, octylphenol, nonylphenol, and dodecylphenol. The above-mentioned arylphenols include phenylphenol, substituted phenylphenol, and cumylphenol. Examples of the aldehyde include formalin, paraformaldehyde, furfural, and hexamethylenetetramine. Inorganic acids include hydrochloric acid, phosphoric acid, sulfuric acid, etc., and organic acids include acetic acid, formic acid, oxalic acid, maleic acid, etc. Examples of the metal oxide of the present invention include titanium oxide, magnesium oxide, zinc oxide, and the like. The present invention contains these three components as essential components, and in particular, by using the phenolic resin of the present invention, it is possible to obtain a rubber adhesive with excellent heat resistance without shortening the adhesive retention time. I can do it. The proportions of the above three components are preferably 40 to 100 parts by weight of the phenol resin and 2 to 20 parts by weight of the metal oxide to 100 parts by weight of the rubber. If the amount of phenolic resin is too small, the effect of the present invention will be small, and if it is too large, the adhesive strength will decrease. Too little metal oxide reduces adhesive strength and heat resistance, while too much metal oxide causes precipitation and phase separation. The rubber adhesive composition according to the present invention includes ketone resin, coumaron-indene resin, xylene resin,
Modifying resins such as petroleum resins, terpene resins, terpene phenol resins, and epoxy resins, additives such as calcium silicate, carbon black, and stearic acid, and other additives such as anti-aging agents, vulcanization accelerators, and curing agents are added as appropriate. Alternatively, organic solvents such as toluene, n-hexane, ethyl acetate, and methyl ethyl ketone may be used. Next, examples of the present invention will be shown. Hereinafter, "parts" are "parts by weight." Example 1 300 g of p-tert-butylphenol, 324 g of formalin, 10 g of potassium tert-butoxide
was placed in a reactor and reacted at 95°C for 2 hours with stirring. After removing the separated water, add 5g of hydrochloric acid and confirm that the pH is 2.1, then reduce the system temperature to 130℃ at 50 to 100mmHg.
A pale yellow transparent phenol resin A with a softening point of 90°C was obtained. Polychloroprene (neoprene
AD, Showa Neoprene Co., Ltd. trade name) 100 parts, magnesium oxide 6 parts, zinc oxide 5 parts, Nokrac PA
(Trade name of Ouchi Shinko Kagaku Kogyo Co., Ltd.) 2 parts were roll kneaded and dissolved in a mixed solvent consisting of 113 parts of toluene, 113 parts of n-hexane and 113 parts of ethyl acetate to obtain a rubber liquid. 45 parts of resin A, 45 parts of toluene, n-
After dissolving in a mixed solvent of 45 parts of hexane and 45 parts of ethyl acetate, the rubber liquid was mixed to obtain an adhesive composition (-A). Comparative Example 1 (Conventional Method) A pale yellow transparent phenolic resin B having a softening point of 93° C. was obtained using the same formulation as in Example 1 and using 12.5 g of barium hydroxide instead of potassium tert-butoxide. An adhesive composition (-B) was obtained in the same manner as in Example 1 using 45 parts of the above resin B. Table 1 shows the physical properties of these adhesive compositions.

[Table] The method for measuring physical properties is described below. Γ Peel strength is 200 on the 5th day after adhesion between stainless steel plate and canvas according to ASTM-D-903-49.
Measurements were made at a speed of mm/min. Γ Heat resistance was measured using ASTM-D-15-88-T3A on the third day after adhering the canvas to each other. For Γ Tack Time, apply the adhesive composition to art paper in advance to a thickness of 0.5 mm using an applicator and leave it at 25°C for 20 hours. Next, the adhesive composition was similarly applied to the iron plate, and at this time, the adhesive composition side of the art paper cut into a tanzak shape was pressed onto the adhesive composition side of the iron plate every 5 minutes using finger pressure. Tear it off immediately. The time from 0 minutes to no longer adhesion was expressed as tack time. For Γ phase separation, 20g of the adhesive composition was weighed into an 18φ test tube, and the state was examined after leaving it at 25°C for 30 days. Example 2 p-phenylphenol 136g, p-tertbutylphenol 30g, paraformaldehyde 75g,
1.12 g of potassium hydroxide was added and the same reaction as in Example 1 was carried out to obtain phenol resin C having a softening point of 97°C. An adhesive composition (-C) was obtained in the same manner as in Example 1 using 45 parts of phenolic resin C. Comparative Example 2 The softening point was determined in the same manner as in Example 2 using 1 g of sodium hydroxide instead of potassium hydroxide.
Resin D was obtained at 123°C. An adhesive composition (-D) was obtained in the same manner as in Example 1 using 45 parts of Resin D. Table 2 shows the physical properties of these adhesive compositions.

[Table] Example 3 Acrylonitrile-butadiene rubber (hiker
1042 manufactured by Nippon Zeon) was masticated and then dissolved in 400 parts of methyl ethyl ketone. This was mixed with 100 parts of the phenol resin C obtained in Example 2 dissolved in 100 parts of methyl ethyl ketone to obtain an adhesive composition (-C). Comparative Example 3 100 parts of the phenol resin D obtained in Comparative Example 2 was dissolved in 100 parts of methyl ethyl ketone to the acrylonitrile-butadiene rubber liquid obtained by the same method as in Example 3, and then mixed with the above rubber liquid to form an adhesive composition. I got (-D). Table 3 shows the physical properties of these adhesive compositions.

[Table] The rubber adhesive composition of the present invention is superior to conventional rubber adhesives in the following points. (1) The rubber adhesive composition of the present invention has improved heat resistance and adhesive strength compared to conventional adhesive compositions. (2) The rubber adhesive composition of the present invention has a practically sufficient tack time and has excellent workability. (3) On the other hand, in the case of chloroprene adhesive compositions, conventional adhesive compositions with good heat resistance tended to undergo phase separation, but the adhesive composition of the present invention does not undergo phase separation. The rubber adhesive composition of the present invention can be widely used as an adhesive composition for building materials, woodworking, shoes, and home appliances that require heat resistance.

Claims (1)

[Scope of Claims] 1 (a) Rubber (b) A heating reaction of 1 mol or more of aldehyde with 1 mol of alkylphenol or arylphenol in the presence of a potassium compound exhibiting basicity, followed by acidification and condensation reaction. A rubber adhesive composition comprising (c) a metal oxide and a phenolic resin having a softening point of 70 to 100°C.