JP2007269988A - Moisture-curing resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a moisture-curing resin composition suitable for bonding a decorative board to a wall or the ceiling during repair of a bathroom because an adhesive layer has flexibility and elasticity over a long period and sufficient storage stability and exhibits high levels of water resistance, while frequent exposure of a conventional moisture-curing resin composition to high humidity after application such as repair of the bathroom causes deterioration of the flexibility of the composition cured product. <P>SOLUTION: The moisture-curing resin composition comprises at least (a) an oxyalkylene-based polymer containing a reactive silicon group, (b) a reaction product of a dibutyltin salt with ethyl orthosilicate, (c) an epoxy resin and (d) a ketimine compound to be a latent curing agent for the (c). The moisture-curing resin composition is characterized as comprising (a) the oxyalkylene-based polymer containing the reactive silicon group, (b) a curing catalyst for the (a), (c) the epoxy resin and (d) the ketimine compound to be the latent curing agent for the (c). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a moisture curable resin composition comprising an oxyalkylene polymer containing a reactive silicon group and an epoxy resin, and excellent in flexibility, water resistance and storage stability.

Epoxy resins are used in many fields, but there is a problem that the peel adhesion strength is small because the cured product has poor flexibility. On the other hand, an oxyalkylene polymer having a reactive silicon group becomes a rubber-like elastic body in a one-pack type and cured at room temperature, and exhibits good peel adhesion strength due to its flexibility, but the cured product has water-resistant adhesion performance. Low is a problem. Therefore, in order to improve the hardness of the epoxy resin cured product and the water-resistant adhesion performance and insufficient strength of the cured oxyalkylene polymer having a reactive silicon group, a curable resin composition in which both are combined has been proposed. Most are two-component types consisting of a main agent and a curing agent, but by using a ketimine compound as an epoxy resin curing agent, a one-component type in which the main agent and (latent) curing agent are mixed in advance has been developed. However, this one-pack type moisture curable resin has poor storage stability, and the crosslinking reaction has progressed during storage, so that it may not be used.
JP-A-63-273629 Japanese Patent Laid-Open No. 4-1220 Japanese Patent Laid-Open No. 5-271389 Japanese Patent No. 3512938

  The problem of the present invention is that the adhesive layer has flexibility and water resistance for a long period of time, has good storage stability, and is applied to the walls and ceilings of parts that become water sources such as around the bathroom, toilet, and kitchen. It is to provide a moisture curable resin composition suitable for plate bonding.

  As a result of studying to solve the above-mentioned problems, (a) an oxyalkylene polymer containing a reactive silicon group, (b) a reaction product of dibutyltin salt and normal ethyl silicate, (c) an epoxy resin, (d ) A moisture-curable resin composition containing a ketimine compound as a latent curing agent in (c), which retains flexibility and water resistance for a long period of time, and is excellent in storage stability The composition was found and the present invention was achieved.

  The moisture curable resin composition of the present invention maintains flexibility and water resistance for a long time with a single solution, and has excellent storage stability. Suitable for adhering a decorative board to the skin.

  Specific examples of the oxyalkylene polymer containing a reactive silicon group as component (a) used in the present invention include Japanese Patent Publication No. 45-36319, Japanese Patent Publication No. 46-12154, and Japanese Patent Publication No. 50-156599. , JP 54-6096, JP 55-13767, JP 55-13468, JP 57-164123, JP 3-2450, US Patent 3,632,557, US Patent 4,345,053, U.S. Pat. No. 4,366,307, U.S. Pat. No. 4,960,844, etc., and JP-A 61-197631, JP-A 61-215622, Oxygen having a narrow molecular weight distribution with a high molecular weight having a number average molecular weight of 6,000 or more and Mw / Mn of 1.6 or less proposed in Japanese Laid-Open Patent Publication Nos. 61-215623 and 61-218632 Alkylene polymer can be exemplified, but not particularly limited thereto. The oxyalkylene polymer containing a reactive silicon group obtained by the above method may be used alone or in combination of two or more. An oxyalkylene polymer obtained by blending a vinyl polymer having a reactive silicon group can also be used.

  The important point in the present invention is to use a reaction product of dibutyltin salt and normal ethyl silicate as component (b). The inventors have examined each curing catalyst for the oxyalkylene polymer having a reactive silicon group described in Patent Documents 1 to 4, but when these are used, the storage stability is not sufficient. Only when a reaction product of dibutyltin salt and normal ethyl silicate is used, the curing catalytic action and storage stability with respect to the oxyalkylene polymer having a reactive silicon group are satisfied.

  The epoxy resin of component (c) used in the present invention is an epichlorohydrin-bisphenol A type epoxy resin, an epichlorohydrin-bisphenol F type epoxy resin, a flame retardant type epoxy resin such as glycidyl ether of tetrabromobisphenol A, a novolak type Epoxy resin, hydrogenated bisphenol A type epoxy resin, glycidyl ether type epoxy resin of bisphenol A propylene oxide adduct, p-oxybenzoic acid glycidyl ether ester type epoxy resin, m-aminophenol type epoxy resin, diaminodiphenylmethane type epoxy resin, Urethane-modified epoxy resin, various alicyclic epoxy resins, N, N-diglycidylaniline, N, N-diglycidyl-o-toluidine, triglycidyl isocyanurate, polyalkylene glycerin Glycidyl ethers of polyhydric alcohols such as alkyl diglycidyl ether and glycerin, epoxidized products of unsaturated polymers such as hydantoin type epoxy resins, petroleum resins, etc., but are not limited to these, and generally The used epoxy resin can be used. Among these epoxy resins, those containing at least two epoxy groups in the molecule are particularly preferable because they have high reactivity during curing, and the cured product easily forms a three-dimensional network structure. More preferred are bisphenol A type epoxy resins or novolac type epoxy resins.

  The ratio of the epoxy resin of component (c) and the oxyalkylene polymer having a reactive silicon group of component (a) is in the range of (a) / (c) = 100/5 to 100 in weight ratio. is there. When the ratio of (a) / (c) is less than 100/5, the effect of improving the toughness and water resistance of the cured epoxy resin is difficult to obtain, and the ratio of (a) / (c) exceeds 100/100. When the oxyalkylene polymer cured product is lost, the soft rubber elasticity is lost, resulting in a remarkably stiff and brittle composition. The preferred use ratio of the component (a) and the component (c) varies depending on the use of the curable resin composition and cannot be determined unconditionally. However, the strength of the cured oxyalkylene polymer as the component (a) is improved. In this case, the component (c) is used in an amount of 5 to 100 parts by weight, more preferably 10 to 60 parts by weight per 100 parts by weight of the component (a).

  The (d) component ketimine compound used in the present invention is a dehydration condensation reaction product between an amine compound having two or more amino groups in the molecule and a ketone compound. Although the basicity of nitrogen in the molecule is weak and it hardly reacts with epoxy resin in the absence of moisture, primary amine is easily generated when reacted with moisture in air, and the reaction proceeds with epoxy resin, There is an advantage that curing does not proceed unless moisture is absorbed. This feature can be used for one-pack type epoxy resins. Specific examples include polyoxypropylenediamine and methylisobutylketone dehydrated, polyoxypropylenetriamine and methylisobutylketone dehydrated. And those obtained by dehydration reaction of polyoxyalkylene diamine and methyl isobutyl ketone, and those obtained by dehydration reaction of hexamethylene diamine and methyl isobutyl ketone.

  In the present invention, a reactive silicon compound other than the component (a) can be used for the purpose of improving adhesion, and a compound having a hydrolyzable functional group that reacts in the presence of moisture and having a molecular weight of 500 or less is preferable. Further, this compound preferably has a functional substituent. Examples of the hydrolyzable functional group include an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an aminooxy group, an amide group, and an alkenyloxy group. Examples of the substituent include an epoxy-containing group, an amino-containing group, an acrylic-containing group, and a mercapto-containing group. Examples of such compounds include silane coupling agents, and these compounds may be used alone or in combination of two or more.

  In the composition of the present invention, various additives such as a dehydrating agent, a physical property adjusting agent, a filler, and an antiaging agent can be appropriately added as necessary. Hereinafter, the present invention will be described specifically by way of examples.

Example 1
As component (a), 150 parts by weight of a propylene oxide polymer having a number average molecular weight of 10,000 containing an average of two methyldimethoxysilyl groups per molecule, and as component (c), an epoxy resin (manufactured by Japan Epoxy Resins Co., Ltd.) "Epicoat 828", trade name) 13 parts by weight, calcium carbonate 300 parts by weight, polypropylene glycol ("P-3000" manufactured by Asahi Denka Kogyo Co., Ltd., trade name) 30 parts by weight were added and stirred at 100 ° C under reduced pressure. Mixed. Here, as component (b), a reaction product of dibutyltin salt and normal ethyl silicate (Neoto U-700 manufactured by Nitto Kasei Co., Ltd., trade name) 3.5 parts by weight, as component (d), ketimine type curing agent ("Eponit K-100" manufactured by Nitto Kasei Co., Ltd., product name) 6.5 parts by weight, vinyltrimethoxysilane ("NUC Silicone A171" manufactured by Nihon Unicar Co., Ltd., product name) 10 parts by weight, γ-Gly 2 parts by weight of cidoxypropyltrimethoxysilane (Toray Dow Corning Silicone Co., Ltd. “SH-6040”, trade name) was added and stirred under reduced pressure to obtain a moisture curable resin composition.
Example 2
A moisture curable resin composition was obtained in the same manner as in Example 1 except that Epicoat 828 was changed to 20 parts by weight and Eponit K-100 was changed to 10 parts by weight.
Comparative Example 1
In Example 1, instead of 3.5 parts by weight of Neostan U-700 as component (b), 3.5 parts by weight of a dibutyltin compound (“Neostan U-220” manufactured by Nitto Kasei Co., Ltd., trade name) was added. Was carried out in the same manner as in Example 1 to obtain a moisture curable resin composition.

  The storage stability was evaluated as follows: the viscosity at 23 ° C. immediately after preparation of the composition and the above composition was 333 ml in volume, and the aluminum foil moisture-proof paper cartridge was filled and sealed, then treated at 40 ° C. for 1 month and then returned to 23 ° C. The viscosity was measured and the magnification of the viscosity after one month with respect to immediately after preparation was determined. The viscosity of the rotor No. of BS type viscometer (manufactured by Toki Sangyo Co., Ltd., single cylinder type rotational viscometer) 7 was used to measure the value at 23 ° C. after 1 minute at 10 rpm.

  The adhesive strength test piece is a non-combustible decorative board having a thickness of 3 mm in accordance with the adhesive strength of the adhesive for wall / ceiling board of JISA1612-1996 and the adhesive strength test method of the adhesive construction method (Eikakasaral, Aika Kogyo Co., Ltd., Product name) and ceramic tile were bonded as a 3 mm thick adhesive layer using a 3 mm thick spacer, and were cured by moisture curing at 23 ± 1 ° C. and 50 ± 5% RH for 7 days. Thereafter, a tensile test after immersion in water at 40 ± 1 ° C. for one month was performed, and the normal tensile adhesive strength, the waterproof tensile adhesive strength, and the fracture state of the adhesive layer were compared. Table 1 shows the results using the adhesives of Examples and Comparative Examples.

Note 1) Storage stability was obtained by dividing the viscosity after storage for 1 month at 40 ° C. by the viscosity immediately after preparation.
Note 2) Normal tensile adhesive strength was measured under the conditions of 23 ± 1 ° C. and 50 ± 5% RH.
The water-resistant tensile adhesive strength was measured in a wet state after being immersed in water at 40 ° C. for 1 month.
cf cohesive failure, pf thin layer cohesive failure

  The compositions described in the examples have a viscosity of 1.2 times after being stored at 40 ° C. for one month, and are in a range where there is no practical problem. On the other hand, the composition described in the comparative example has a viscosity of 1.5 times, and there is a concern that workability may be reduced.

It is highly durable for adhesives and caulking in fields exposed to high humidity environments in construction and civil engineering. It is useful as a wall / ceiling veneer adhesive for areas such as new constructions and renovations in houses, bathrooms, toilets, and kitchen areas.

Claims (1)

  (A) an oxyalkylene polymer containing a reactive silicon group, (b) a reaction product of dibutyltin salt and normal ethyl silicate, (c) an epoxy resin, and (d) a latent curing agent for (c). A moisture curable resin composition comprising a ketimine compound.