JPS63125588A - Two-pack urethane adhesive - Google Patents

Abstract

PURPOSE:To prepare a two-pack urethane adhesive having improved initial adhesive strength and cohesive strength, by combining a chief agent comprising a water-soluble urethane prepolymer having a particular compsn. and a high- molecular polyurethane rubber with a curing agent comprising water as a main component. CONSTITUTION:A poly(alkylene ether) polyol having an ethylene oxide content of 30-90mol% is reacted with an excess of a polyisocyanate (e.g., diphenylmethane 4,4'-diisocyanate), thereby preparing a water-soluble urethane prepolymer. 100pts.wt. aforesaid prepolymer is mixed with 1-5pts.wt. high- molecular polyester urethane rubber, thereby preparing a chief agent. The chief agent thus prepared is combined with a curing agent comprising water as a main component, thereby preparing a two-pack urethane adhesive. It is pref. that a reaction catalyst, such as triethylenediamine or thiourea be contained in the curing agent.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a two-component urethane adhesive, more specifically, a two-component adhesive in which a water-soluble urethane prepolymer and water are the main component and the curing agent component, respectively. By adding high-molecular polyester urethane rubber to the ingredients,
This invention relates to a urethane adhesive that has improved initial adhesive strength and cohesive strength of a cured adhesive layer.

Prior Art and Problems to be Solved This type of adhesive, that is, a two-component urethane adhesive that uses water-soluble urethane prepolymer as the main ingredient and water as a curing agent, is already known and has poor adhesive workability. Good, contributes to improved productivity, and is particularly useful for bonding porous materials (wood, slate, paper, cloth, felt, plastic foam, etc.) to each other or porous materials to non-porous materials (metal, plastic sheets, etc.) (For example, Japanese Patent Application Laid-Open No. 58-523
(See Publication No. 78). However, when used, for example, on an automobile manufacturing line to join the pipes of seats manufactured by laminating a nonwoven fabric (surface material) to a urethane foam core material, the initial adhesive strength is lower than that of general rubber adhesives. The drawbacks are that the rise is slow and the cohesive force of the adhesive layer is insufficient.

Therefore, the inventors of the present invention have conducted repeated studies to improve the problems of initial adhesive strength and cohesive strength, and have found that this problem can be solved by adding urethane rubber with a certain degree of high crystallinity to the main component. This discovery led to the completion of the present invention.

Structure and Effects of the Invention Namely, the present invention provides (a) 100 parts (parts by weight) of a water-soluble urethane prepolymer which is a reaction product of a polyalkylene ether polyol with an ethylene oxide molar ratio of 30 to 90% and an excess of polyisocyanate; , hereinafter the same) and (b) a main agent consisting of 1 to 5 parts of high molecular weight polyester urethane rubber, and (C) a curing agent whose main component is water. It is something to do.

The water-soluble urethane prepolymer (a) in the present invention is
It is produced by reacting polyalkylene ether polyol with excess polyisocyanate, but the molar ratio of ethylene oxide in polyalkylene ether polyol is 3.
It is 0-90%.

The above polyalkylene ether polyol is usually a compound containing two or more hydroxyl groups (hereinafter referred to as polyol) and ethylene oxide in the molecule in a molar ratio of 30 to 9.
It is manufactured by adding it so that it contains 0%. For example, as polyols, ethylene glyconohediethylene glyconopepropylene glyconohedipropylene, 1,1conopebutylene glycol, neopentyl glycol, 1
, 6-hexanediol, glycerin, trimethylolpropane, trimethylolethane, hexanetriol, pentaerythritol, sorbitol, sucrose, etc., using known methods to prepare ethylene oxide or other alkylene oxides such as propylene oxide and butylene oxide. Manufactured by addition reaction or co-addition reaction. Considering hydrophilicity and workability, the molecular weight of polyalkylene ether polyol is 1000 to 20000, especially 100.
Those in the range of 0 to 5000 are preferred, and among polyalkylene ether polyols, polyalkylene ether diols are preferred.

As the above-mentioned polyinsyanate, those used in the production of ordinary urethane prepolymers can be used, for example,
Toluene diincyanate and diphenylmethane-4
, 4'-diisocyanate, purified products and crude products, etc. are used. In particular, diphenylmethane-4,
4'-diisocyanates are suitable. The reaction ratio of polyalkylene ether polyol and polyisocyanate is N
The urethane prepolymer obtained has a residual active incyanate group of 4 to 13% and a viscosity of 3000 to 1000.
0 cps is preferable in terms of reactivity, workability, performance, etc.

The polyester urethane rubber (b) in the present invention is
A polyester obtained by reacting a polycarboxylic acid (phthalic acid, adipic acid, trimerized lyluic acid, maleic acid, dimer acid, etc.) with a polyol is reacted with approximately the same amount of polyisocyanate on its terminal hydroxyl group. It refers to a polymer with a molecular weight of usually 10,000 to 10,000.
5oooo is preferred. Such polymeric polyester urethane rubber itself has high crystallinity and contributes to the development of the above-mentioned initial adhesive force and cohesive force. The amount used is selected within the range of 0.5 to 5 parts, preferably 1 to 3 parts, based on 100 parts of the water-soluble urethane prepolymer. If it is less than 0.5 part, the desired effect cannot be obtained, and if it exceeds 5 parts,
The viscosity becomes too high to be suitable for spray application.

The curing agent (c) mainly composed of water in the present invention is mainly composed of water having an active hydrogen group that reacts with the active incyanate group of the water-soluble urethane prepolymer (a), and in which various reaction catalysts are added. It is preferable to add the following to form an aqueous solution that can be sprayed. This catalyst includes organic amines such as triethylenediamine, triethylamine, dimethylethanolamine, tetramethylpropylenediamine, and tetramethylenetriamine, as well as inorganic basic compounds such as borax and sodium hydroxide, urea, thiourea, amino acid salts, and basic At least one of a number of amino acids can be used, but urea, thiourea, amino acid salts, and basic amino acids are particularly preferred from the viewpoint of toxicity, odor, water solubility, economic efficiency, etc., and when thiourea is used, shows the characteristic that the heat resistance of the adhesive after curing is significantly improved.

The two-component urethane adhesive according to the present invention is composed of a main ingredient consisting of water-soluble urethane prepolymer gloss and polyester urethane rubber (b) in the above-mentioned predetermined proportions, and a curing agent (c). If necessary, appropriate amounts of ordinary fillers, anti-aging agents, coloring pigments, reaction catalysts, adhesion agents, solvents, plasticizers, etc. may be added to the main component. Further, appropriate amounts of ordinary adhesion agents, dyes and pigments, fillers, surfactants, etc. may be added to the curing agent (C) as necessary. In particular, the addition of a surfactant improves the compatibility with the urethane prepolymer, and the addition of dyes and pigments makes it possible to mix the spray surface and check the amount of coating. Furthermore, by adding a filler and a water-soluble resin, it is possible to prevent penetration into porous materials and reduce costs.

The two-component urethane adhesive of the present invention configured as described above is extremely fast when the main ingredient and the curing agent are mixed or brought into contact with each other.
Since the curing reaction occurs in several tens of seconds, the adhesive is usually applied by spraying the base agent and curing agent separately.
It is preferable to simultaneously spray the adhesive using a so-called double-headed gun, and apply the base agent and curing agent to one of the surfaces to be adhered while contacting and mixing them in the air, and then overlap and adhere the other surface.

Next, the present invention will be explained in more detail with reference to Production Examples, Examples, and Comparative Examples. In the example sentences, parts mean parts by weight.

Production Example 1 (Production of urethane prepolymer) Average molecule @
100 parts of diphenylmethane-4,4'-diisocyanate (NG
OloH ratio = 6.0) was added to a stirrable container with a heat-insulating jacket, mixed, and reacted for 3 hours at an elevated temperature of 80°C, resulting in a residual active incyanate group of 9.33% and a viscosity of 4000 cps. A water-soluble urethane prepolymer is obtained.

After adding 25 parts of methylene chloride to 300 parts of this urethane prepolymer and stirring uniformly, add 18% of a 20% methylene chloride solution of polyurethane rubber (manufactured by Bayer AG, Dessaucoal 500, molecular weight approximately 34,000) prepared in advance. .75 parts were added and stirred uniformly to prepare a main ingredient. The viscosity was 1,000 cps/20°C.

Production Examples 2 to 8 In the same manner as Production Example 1, water-soluble urethane prepolymers were prepared using the polyalkylene ether polyols and polyisocyanates shown in Table 1.

20 parts of methylene chloride was added to 80 parts of each of the water-soluble urethane prepolymers obtained in Table 1, stirred with fft, and urethane rubber (manufactured by Bayer AG, Desmocol 500) was added.
5 parts of a 20% methylene chloride solution was added and stirred uniformly to prepare the main ingredients shown in Table 2.

Production Examples 9 to 11 25 parts of methylene chloride was added to 300 parts of the urethane prepolymer obtained in Production Example 1, and after mixing and stirring, 20 parts of polyurethane rubber (Desmocol 5OO manufactured by Bayer) was added.
% methylene chloride solution was added in the proportions shown in Table 3 to prepare a base agent.

Production Examples 12 to 19 25 parts of methylene chloride was added to 300 parts of the urethane prepolymers obtained in Production Examples 2 to 8, and after stirring uniformly, urethane rubber (Desmocol 53 manufactured by Bayer) was added.
18.75 parts of a 20% methylene chloride solution having a molecular weight of about 34,000) was added to prepare the main ingredients shown in Table 3.

Table 3 Table 3 (continued) Note) x Urethane rubber 20% methylene chloride solution production example 20 A curing agent was prepared by dissolving 10 parts of urea in 90 parts of water.

Production Examples 21 to 25 - Curing agents were prepared in the same manner as in Production Example 20 using the catalysts shown in Table 4.

Table 4 Example 1 The base material obtained in Production Example 1 and the curing agent obtained in Production Example 20 were applied to an injection molded urethane foam for automobile seats.
The coating was applied at a rate of 0 g/d and 35 g/d using a double-headed spray gun so as to be mixed in the air, and a polyester woven fabric was superimposed thereon and pressed at 80° C. for 15 seconds. 1. Peel strength after 10 seconds after removal from the pressurized press. OL!
' / i n , and the urethane foam was destroyed.

Comparative Example 1 Instead of the main ingredient of Example 1, a polyalkylene ether polyol containing propylene oxide as the main component (Sunix pp3000 manufactured by Sanyo Chemical Industries, Ltd., diol of 100% propylene oxide, molecule ff13000)
A urethane prepolymer (NC010H ratio: 4.01, residual active incyanate group: 6.3%, viscosity: 3500) was prepared in the same manner as in Production Example 1 using 300 parts of diphenylmethane-4°4'-diisocyanate. 300 parts of polymer, 25 parts of methylene chloride and polyurethane rubber (Desmocol 500 manufactured by Bayer)
A base resin was prepared by adding 18.75 parts of a 20% methylene chloride solution, and the curing agent obtained in Production Example 20 was pressed for 60 seconds in the same manner as in Example 1, but the peel strength was 0.
．． 5~/in, and 90 seconds of pressure bonding was required to reach an adhesive strength that would destroy the urethane foam.

Comparative Example 2 A base material without adding urethane rubber was prepared in Production Example 1, and 2 was prepared in the same manner as in Example 1 using the curing agent of Production Example 20.
After hot pressing for 5 seconds, the peel strength was 0.5 K9
/in or less, and the hot pressing time required to destroy the urethane foam was I seconds.

Examples 2 to 24 The urethane foam used in Example 1 was added with 70 P/i of the main agent obtained in Production Examples 1 to 19 and 35 P/rd of the curing agent obtained in Production Examples 20 to 25 as shown in Table 5. Using the same method as in Example 1, a polyester woven fabric was superimposed on the urethane foam, and hot pressing was performed. The test measured the time required for hot pressing until the urethane foam was destroyed. The results are shown in Table 5.

Table 5 (Continued) Test 1 In order to test the blending effect of polyurethane rubber, the amount of polyurethane rubber added was varied in the base material containing the urethane prepolymer obtained in Production Example 1, and the curing agent of Production Example 20 was used. Adhesion was performed in the same manner as in Example 1, and the hot pressing time until the polyurethane foam broke was measured in a peel test. The results are shown in Table 6.

Note *) When the amount of urethane rubber added was 10%, the viscosity of the base resin was high and spray coating was not possible, so mix the base resin and hardening agent in a ratio of 2 = 1 with a static mixer and use a brush. It was applied.

Test 2 Using the base resin and curing agent used in Test 1, the adherend was No. 9 Campus/No. 9 Campus, and the pressing temperature was 80°C.
Bonding was carried out in the same manner as in Example 1 under the conditions of 20°C and 20°C. Table 7 shows the peel strength test results. In addition, the state of destruction was all a-group failure.

Table 7 (KIi/in) Note x) Test conducted using the method shown in Table 6. As is clear from the test results, when polyurethane rubber is added to the base material, the initial adhesive strength improves, and as a result, the hot press adhesive work is shortened. It can be done in time. On the other hand, if the urethane rubber is 10% by weight or more, the main ingredient cannot be sprayed.

Claims (1)

[Claims] 1. (a) 100 parts by weight of a water-soluble urethane prepolymer which is a reaction product of a polyalkylene ether polyol with an ethylene oxide molar ratio of 30 to 90% and an excess of polyisocyanate; A two-component urethane adhesive characterized by comprising a main agent consisting of 1 to 5 parts by weight of molecular polyester urethane rubber, and (c) a curing agent whose main component is water. 2. The molecular weight of polyester urethane rubber (b) is 100
00 to 50,000. 3. The adhesive according to item 1 above, wherein the curing agent (c) contains at least one member selected from the group of organic amines, inorganic basic compounds, urea, thiourea, amino acid salts, and basic amino acids as a reaction catalyst. agent.