JPH0153912B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an adhesive composition having excellent water resistance and containing carboxylated polychloroprene as a basic resin and suitable for use as a contact adhesive. Contact-type adhesives are generally adhesives that are applied to each surface of an adherend to be bonded, left to dry for a while, and then the coated surfaces are simply brought into contact (contact), especially by applying heat and pressure for a long time. An adhesive that can be bonded without requiring curing. Adhesive compositions in which a solid content mainly composed of polychloroprene is dispersed in an aqueous medium have traditionally been used as contact adhesives. Adhesive compositions containing additives are known. This composition exhibits excellent high-temperature adhesive strength as an adhesive due to the progress of the crosslinking reaction between the carboxylated polychloroprene and the polyvalent metal oxide at room temperature. Since adhesion is impaired, an alkali such as sodium hydroxide or potassium hydroxide has been added together with a polyvalent metal oxide in order to slow down the speed of the crosslinking reaction. Therefore, when this composition is used, alkaline content remains in the adhesive layer formed between the adherends, resulting in extremely poor water resistance, making it difficult to use in practical applications where water comes into contact with the adhesive part. The current situation was that it was not possible. The present invention was made in view of the drawbacks of the above-mentioned conventional adhesive compositions in which the solid content is dispersed in an aqueous medium, and an object of the present invention is to provide an adhesive composition in which the solid content is dispersed in an aqueous medium and has particularly excellent water resistance. The gist of the adhesive composition is an adhesive composition in which carboxylated polychloroprene, a polyvalent metal compound, rosin phenol, and ammonia or an organic amine having a carbon number of 5 or less are added and dispersed in an aqueous medium. The carboxylated polychloroprene in the present invention has a carboxyl group in the molecule, preferably two or more carboxyl groups in one molecule, and is, for example, a carboxyl group-containing polymerizable monomer such as chlorobutadiene and methacrylic acid. mer by a conventionally known method such as an emulsion polymerization method. In the present invention, the polyvalent metal compound refers to an oxide, hydroxide, or salt of a metal cation of group 1 to 3 with an inorganic or organic acid, and specific examples include magnesium oxide, calcium oxide, zinc oxide,
Metal oxides such as aluminum oxide, metal hydroxides such as magnesium hydroxide, calcium hydroxide, zinc hydroxide, aluminum hydroxide, magnesium sulfate, calcium sulfate, zinc sulfate, aluminum sulfate, magnesium phosphate, calcium phosphate, phosphoric acid aluminum, magnesium silicate,
Examples include inorganic acid salts such as aluminum silicate, and organic acid salts such as calcium acetate, aluminum acetate, zinc acetate, calcium benzoate, zinc benzoate, and zinc carbamate, and zinc compounds are particularly preferably used. These metal compounds are used alone or in appropriate combinations, and the amount used varies depending on the type of metal compound, type of adherend, purpose, etc., but if it is too small, the adhesive layer that is finally formed will be damaged. If the amount is too large, the adhesive layer may become brittle, so it is generally added between 0.3 and 15 parts by weight per 100 parts by weight of the carboxylated polychloroprene.
The amount is preferably 0.5 to 6 parts by weight. In the present invention, rosin phenol means a reaction product of rosin and an aromatic alcohol, and most of the rosin phenol is presumed to be a condensation product. In particular, the reaction product of phenols and rosin containing a large amount of abietic acid, dihydroabietic acid, tetrahydroabietic acid, or dextrobimaric acid as a resin acid gives the composition adhesiveness and adhesive strength to the adherend surface. It is preferable because it has a large property of imparting . Rosin phenol may be used in combination with other tackifying resins such as coumaron-indene resins, aliphatic and aromatic petroleum resins, and terpenes, and the amount used is generally 5 parts by weight per 100 parts by weight of carboxylated polychloroprene. ~200 parts by weight, preferably 20
~100 parts by weight, and is usually used in the form of a pre-dissolved or dispersed solution in a solvent such as toluene or xylene. Ammonia in the present invention or carbon number is 5
The following organic amines are usually used as aqueous solutions, and specific examples of organic amines include methylamine,
In addition to aliphatic amines such as ethylamine, morpholine and the like may be mentioned, and ammonia is particularly preferably used. The amount used is generally 0.8 to 1 mole of carboxyl group of the above carboxylated polychloroprene.
The amount is 2.5 mol, preferably 1.0 to 1.7 mol. Particulate silica may be added and dispersed in the composition of the present invention for the purpose of improving adhesion to adherends and water resistance of the formed adhesive layer. Such silica is used in the form of a colloid that has been dispersed in water in advance and an electric double layer is formed around the silica particles by alkali ions, but in some cases carboxylated polychloroprene, etc. The essential components of the present invention may be added directly to the aqueous dispersion composition. In addition, the composition of the present invention may further contain antioxidants such as hindered phenols, colorants, fillers, surfactants, plasticizers, thickeners, film formation promoters, natural or synthetic rubber latex, etc. You can leave it there. The amount of the aqueous medium, ie, water, and the solvent added as necessary in the composition of the present invention is not particularly limited, but if it is too small, the viscosity of the composition will be high and the workability when applying it to the adherend will be impaired. If the amount is too high, the number of steps required for drying will increase, so it is generally set at 30 to 80% by weight. Also, the amount of water in the aqueous medium is usually 50% by weight.
This is considered to be the above. As the adherend, metals such as iron and various synthetic resins are usually used, but wood and the like can also be used. The reason why the composition of the present invention forms an adhesive layer with excellent water resistance is not fully clear, but for example, ammonia reacts more easily with carboxylated polychloroprene than with the polyvalent metal compound, so it is dispersed in an aqueous medium. In the composition, the carboxylated polychloroprene forms an ammonium salt, and the crosslinking reaction between the metal compound and the polychloroprene is inhibited, but as the composition is applied to the adherend and dried, the ammonia content evaporates. Then, for example, when the coated adherends are in contact with each other, the crosslinking reaction between the carboxylated polychloroprene and the polyvalent metal proceeds at room temperature, and rosin phenol is used as the tackifying resin. It is presumed that this was due to the fact that The adhesive composition of the present invention has the above-mentioned structure, and has excellent normal adhesive strength, and has better heat resistance and water resistance than conventional contact adhesives containing polychloroprene. This forms an adhesive layer. The present invention will be explained in more detail below with reference to Examples. Example 1 5 parts by weight of polyethylene glycol alkyl phenyl ether and 30 parts by weight of water as surfactants were added to a solution of 50 parts by weight of rosin phenol (Resin SP560, manufactured by Schenecta Day Chemical Co., Ltd.) dissolved in 25 parts by weight of toluene and heated at high speed. The mixture was mixed using a stirrer to obtain a rosin phenol emulsion. 200 parts by weight of carboxylated polychloroprene latex (Neoprene Latex 115, solid content 47%, manufactured by Showa Neoprene Co., Ltd.) was added to this emulsion and stirred well.
While stirring, add 3 parts by weight of 28% ammonia water (the molar ratio of ammonia to the carboxyl group of carboxylated polychloroprene is 1.5), and then add a dispersion of 3 parts by weight of activated zinc white in 4 parts by weight of water. The mixture was added and stirred to obtain a contact type adhesive composition dispersed in an aqueous medium. Apply this adhesive to a 25mm x 125mm x 0.6mm aluminum plate and a 25mm x 125mm cotton cloth (3 coats).
After drying at 80°C, the aluminum plate and cotton cloth were bonded together using a hand roll to form a test piece. After leaving the test piece at room temperature for 4 days, it was heated to 20℃.
The 180° peel strength was measured to determine the normal adhesive strength. or,
The remaining unmeasured test pieces were placed in water at room temperature for 4 days, and immediately after being taken out, the 180° peel strength was measured at 20°C to determine the water-resistant adhesive strength. The results are shown in Table 1. Example 2 The same as Example 1 except that 3 parts by weight of zinc hydroxide was used instead of 3 parts by weight of activated zinc white in Example 1.
An adhesive composition was prepared in the same manner as above. A test piece was prepared using this composition in the same manner as in Example 1, and the normal adhesive strength and water-resistant adhesive strength were determined. The results are shown in Table 1. Example 3 An adhesive composition was prepared in the same manner as in Example 1 except that 50 parts by weight of Barcam TD2615 (manufactured by Dainippon Ink Chemical Co., Ltd.) was used instead of 50 parts by weight of Resin SP560 used in Example 1 as the rosin phenol. were prepared and their physical properties were measured, and the results are shown in Table 1. Example 4 As rosin phenol, 50 parts by weight of Tamanol 803 (manufactured by Arakawa Chemical Industry Co., Ltd.) was used instead of 50 parts by weight of Resin SP560.
An adhesive composition was prepared in the same manner as in Example 1 except that parts by weight were used, and its physical properties were measured. The results are shown in Table 1. Examples 5 and 6 Adhesive compositions having the compositions shown in columns 5 and 6 of Table 1 were prepared, and their physical properties were measured, and the results are shown in Table 1. Example 7 An adhesive composition was prepared in the same manner as in Example 1, except that 25 parts by weight of rosin phenol and 25 parts by weight of polymerized rosin (Dimarex, manufactured by Hercules) were used instead of 50 parts by weight of rosin phenol in Example 1. were prepared and their physical properties were measured, and the results are shown in Table 1.

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[Table] Comparative Example 1 In Example 1, rosin phenol (resin
An adhesive composition was prepared in the same manner as in Example 1, except that 50 parts by weight of α-pinene phenol (YS Polyster 2130, manufactured by Yasushi Kogyo Co., Ltd.) was used instead of 50 parts by weight (SP560), and its physical properties were determined. The results are shown in Table 2. Comparative Examples 2 to 7 Adhesive compositions having various compositions shown in Table 2 were prepared and their physical properties were measured, and the results are shown in Table 2.

【table】

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Claims (1)

[Scope of Claims] 1. An adhesive composition comprising carboxylated polychloroprene, a polyvalent metal compound, rosin phenol, and ammonia or an organic amine having 5 or less carbon atoms added and dispersed in an aqueous medium. 2. The composition according to item 1, wherein the polyvalent metal compound is a zinc compound. 3. The composition according to item 1 or 2, wherein the polyvalent metal compound is a polyvalent metal oxide or hydroxide. 4. The composition according to any one of Items 1 to 4, wherein the amount of the polyvalent metal compound added is 0.3 to 15 parts by weight based on 100 parts by weight of carboxylated polychloroprene. 5. The composition according to any one of Items 1 to 4, wherein the amount of rosin phenol added is 5 to 200 parts by weight per 100 parts by weight of carboxylated polychloroprene. 6 Items 1 to 5, wherein the amount of ammonia or organic amine added is 0.8 to 2.5 mol per mol of carboxyl group of carboxylated polychloroprene.
The composition according to any one of the above.