JPS63137980A - Adhesive composition - Google Patents

Abstract

PURPOSE:To obtain a highly adhesive composition of low foamability, with low viscosity at early stage after blending of the constituents, good in workability, by blending an urethane prepolymer, polyhydroxy compound, amine compound and curing catalyst so that the equivalent ratio of the NCO group to the active hydrogen be specified. CONSTITUTION:The objective composition can be obtained by blending (A) an urethane prepolymer having at least two NCO groups, (B) a polyhydroxy compound, (C) a polyamine compound (e.g., 4,4'-diaminodiphenylmethane), (D) a monoamine compound having NH2 group and other functional group reactive with NCO except NH group (e.g., monomethanolamine), and (E) a curing catalyst in such equivalent ratios as to satisfy the following relationships: (i) total active hydrogen in B and C/NCO = 0.8-1.5, (ii) total active hydrogen in the NH2 and NH in C and D/NCO = 0.2-0.9, (iii) active hydrogen in the NH2 and NH in D/active hydrogen in the NH2 in C = 2.1-9.0.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a low-foaming urethane adhesive composition,
More specifically, the present invention relates to an adhesive composition useful for adhering glass fiber reinforced plastics (FRP), wood, inorganic materials, etc. used in applications such as automobiles, ships, and buildings.

<Conventional technology> Urethane adhesives react with moisture in the air and moisture on the surface of the adherend to generate carbon dioxide gas, which forms bubbles in the adhesive layer.
May cause strength reduction.

In order to avoid this, there are methods to prevent foaming by limiting the isocyanate compounds and polyol compounds used (Japanese Patent Laid-Open No. 126297/1982), or methods to prevent foaming by adding a carbon dioxide absorbent in advance Kaisho 60-1
88455) etc. are known.

However, even with the above method, it is not possible to suppress foaming and ensure good workability in practical use for urethane adhesives having high adhesive strength. -The six applicants are:
First, a method for preventing foaming of urethane sealants by using a specific amine compound (Japanese Unexamined Patent Publication No. 1983-1999)
90284), but this composition has high viscosity, poor workability, and insufficient adhesive strength, and is not preferred as a urethane adhesive.

<Problems to be Solved by the Invention> The purpose of the present invention is to solve the above-mentioned drawbacks of the prior art and provide a urethane adhesive composition that prevents foaming, has low viscosity, good workability, and high adhesive strength. It's about doing.

Means for Solving the Problems> The present invention provides: (a) a urethane prepolymer having two or more isothiaphor 1-groups, (b) a polyhydroxy compound having two or more OH groups, (c) An adhesive composition comprising a polyamine compound having two or more NH2 groups, (d) a monoamine compound having a functional group capable of reacting with NH2 groups or isocyanate groups other than NH groups, and (e) a curing catalyst. Then, the total of active hydrogens of component (b), component (C), and component (d) that can react with the group to isocyane-1 is (a
) 0.8 to 1.5 per isocyanate group of component
equivalent, and the total of the NH2 groups of components (c) and (d) and the active hydrogens possessed by the NH groups is 0.2 to 0.0.0. g equivalent, and the NH2 group of component (d) and the active hydrogen of the NH group are 2 per active hydrogen of the NH group of component (c).
．． The present invention provides an adhesive composition characterized in that it has an equivalent weight of 1 to 9.0.

The urethane prepolymer having two or more isocyanate groups, which is the component (a) in the present invention, is composed of, for example, a polyester polyol or polyether polyol having two or more hydroxyl groups, a compound having active hydrogen such as a polyamine, and an organic polyisocyanate compound. It can be obtained by reacting with in a conventional manner.

The manufacturing conditions are not particularly limited, but include a reaction temperature of 80 to 100°C and a reaction time of about 2 to 4 hours. Completion of the reaction is confirmed by measuring free isocyanate groups by conventional methods.

Examples of the polyester polyol include polyester polyols obtained by reacting polyols with dicarboxylic acids, polyester polyols obtained by ring-opening polymerization of lactones, and the like. Examples of polyols include ethylene glycol, propylene glycol, 1,6 hexanediol, diethylene glycol, neopentyl glycol, bis(hydroxymethyl)cyclohexane, bis(hydroxyethyl)benzene, trimethylolpropane, glycerin, and polyether polyol (polyether polyol). Examples of dicarboxylic acids include succinic acid, glutamic acid, adipic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, terephthalic acid, and dimer acid.

Examples of the polyether polyol include compounds having a structure in which an alkylene oxide is added to an active hydrogen-containing compound such as a polyhydric alcohol, a polyhydric phenol, ammonia, an amine, or a polycarboxylic acid. Here, examples of the polyhydric alcohol include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, sucrose, etc. Examples of polyhydric phenols include pyrogallol, hydroquinone, bisphenol A, etc.; examples of amines include butylamine, ethylenediamine, trimethylenediamine, diethylenetriamine, cyclohexylenediamine, dicyclohexacylmethanediamine, inphoronediamine, phenylenediamine, and triamine. Diamine, xylylene diamine, diphenylmethane diamine, polyphenylmethane polyamine.

Piperazine, amine ethylpiperazine, monoethanolamine, jetanolamine, triethanolamine, etc., and polycarboxylic acids such as succinic acid, adipic acid,
Phthalic acid, terephthalic acid, trimellitic acid, etc. are used as alkylene oxide such as ethylene oxide (hereinafter E
(abbreviated as O), propylene oxide (hereinafter abbreviated as PO)
, butylene oxide, tetrahydrofuran, styrene oxide, epichlorohydrin and the like.

The molecular weight of the polyester polyol and polyether polyol is usually 300 to 10,000, preferably 500 to 3,000.

The polyamines include aliphatic polyamine compounds such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, cyclohexylenediamine, and 0-phenylenediamine. , m-phenylenediamine, p-phenylenediamine, 4.4'
- Diaminodiphenylmethane, 4,4'-diaminophenyl sulfone, 4,4'-diaminodiphenyl ether, 2,4-diaminodiphenylamine, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, 2,4
- Aromatic polyamine compounds such as diaminotoluene can be exemplified.

Examples of the organic polyisocyanate compound include ethylene diisocyanate and ethylidene diisocyanate-1.
-, aliphatic polyisocyanates such as propylene-1,2-diisocyanate, hexamethylene diisocyanate, cyclohexane-1,2-diisocyanate, hydrogenated xylylene diisocyanate, metaphenylene diisocyanate, 2,4-tolylene diisocyanate, 2,
6-Toluylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate condensate, 3,3'-dimethyl-4
, 4'-diphenylene diisocyanate, 3,3'-dimethoxy-4,4'-diphenylene diisocyanate,
4.4'-diphenylene diisocyanate, triphenylmethane-triisocyanate, 1,5-naphthalene diisocyanate, furfurylidene diisocyanate,
Examples include aromatic polyisocyanate compounds such as xylylene diisocyanate and polymers thereof.

These can also be used in combination.

As the polyhydroxy compound having two or more hydroxyl groups, which is the component (b) in the present invention, the polyether polyols, polyester polyols, etc. used in the synthesis of the urethane prepolymer, which is the component (a), can be used. , and further include polyether ester polyols and acrylic-modified or epoxy-modified polyols thereof.

As the polyether ester polyol.

A polyether ester polyol obtained by reacting a polyoxyalkylene polyol with a polycarboxylic acid anhydride and a cyclic ether compound described in Japanese Patent Publication No. 48-10078 can be exemplified.

These can also be used in combination.

As the polyamine compound having two or more NH2 groups, which is the component (c) in the present invention, the above-mentioned polyamines used in the synthesis of the urethane prepolymer, which is the component (a), can be used. , ethylenediamine and diethylenetriamine, and among the aromatic polyamine compounds, 4,4'-diaminodiphenylmethane is preferred. These may be used in combination.

Examples of monoamine compounds having a functional group capable of reacting with an NH group or an isocyanate group other than an NH group, which is component (d) in the present invention, include monomethanolamine, dimetatoolamine, monoethanolamine, jetanolamine, and isopropanolamine. Amino alcohols such as toolamine, 0-aminophenol, m-aminophenol, p-
Aminophenol, 0-aminobenzyl alcohol, m
-aminobenzyl alcohol, 2-amino-4-chlorophenol, 2-amino-p-cresol, 4-amino-m
- aminophenols such as cresol, 6-amino-m-cresol, 4-amino-2,6 dichlorophenol,
Examples include aminothiophenols such as 2-aminothiophenol, 3-aminothiophenol, and 4-aminothiophenol, with aminoalcohols being particularly preferred. These may be used in combination.

As the curing catalyst which is component (e) in the present invention, a so-called urethane catalyst is used. Specific examples include stannous acetate, stannous octanoate, and stannous lauric acid.
tin, stannous carboxylic acids such as stannous oleate, dibutyltin diacetate, dibutyltin dilaurate,
Dialkyltin salts of carboxylic acids such as dibutyltin maleinate, dibutyltin di-2-ethyl-hexoate, dilauryltin diacetate, dioctyltin diacetate, 1-helimethyltin hydroxide, tributyltin hydroxide,
Alkyltin hydroxides such as trioctyltin hydroxide and dibutyltin oxide, dialkyltin oxides such as dioctyltin oxide and dilauryltin oxide, dialkyltin dichlorides such as dibutyltin dichloride and dioctyltin dichloride, triethylamine, benzyldimethylamine, tertiary amines such as triethylenediamine and tetramethylbutanediamine, phenol salts, stearates, oleates or formates of 1,8-diazabicyclo(5,4,0)undecene-7 (hereinafter referred to as rDBUJ); and quaternary ammonium salts.

In the present invention, component (b), component (c), and (
It is necessary that the total amount of active hydrogen that can react with the isocyanate group in component d) is 0.8 to 1.5 equivalents of the isocyanate group in component (a). 0.
If the amount is less than 8 equivalents, foaming cannot be sufficiently prevented. Also 1
If the amount exceeds 5 equivalents, the molecular weight of the cured product will not be sufficiently large and a practically sufficient adhesive strength will not be obtained.

In addition, in the present invention, the sum of active hydrogens possessed by the NH2 groups and NH groups of the components (c) and (d) is (a
) 0.2 to 00 g per equivalent of isocyanate group of component
Equivalence is required. Total active hydrogen is 0.2
If it is less than the equivalent amount, it will not be effective in preventing foaming, and if it is used in excess of 00 g equivalent, the viscosity of the adhesive composition will become too high and the workability will decrease.

Furthermore, in the present invention, component (d) NH2 group and N
The active hydrogen contained in the H group is required to be 2.1 to 9.0 equivalents per equivalent of active hydrogen in the NH2 group of component (C). If the amount of active hydrogen is less than 2.1 equivalents, the viscosity of the adhesive composition will become too high and workability will be reduced, and if it is used in excess of 9.0 equivalents, the crosslinking density will be low in the early stage of curing of the adhesive composition. Foaming cannot be suppressed.

When the adhesive composition of the present invention is used for adhesion and needs to have a high viscosity during application in order to place emphasis on preventing thickening and sagging, component (C) should be added in large amounts to inject or spread over a large area. When coating requires low viscosity during application,
Another feature of the present invention is that the initial viscosity of the adhesive composition can be controlled by varying the equivalent ratio of active hydrogen in component (c) and component (d), such as by increasing the amount of component (d).

In addition, in the present invention, the amount of curing catalyst used is usually (
a) 0.0% in the case of a soot-based catalyst based on 100 parts by weight of component.
0.01 to 0.5 parts by weight, and 0.01 to 5 parts by weight in the case of tertiary amines, salts of DBU, and quaternary ammonium salts.

Further, in the present invention, the total amount of components (b), (c), (d) and (e) used is usually 100% of component (a).
10 to 200 parts by weight, preferably 50 to 200 parts by weight
It is 150 parts by weight.

In the present invention, in order to impart desired physical properties and viscous properties to the adhesive composition, such as prevention of sagging and shape retention,
Inert fillers, plasticizers, etc. may also be added. Inert fillers include, for example, dry carbon black, platelet silica, spherical glass particles, titanium dioxide, talc, calcium carbonate, zinc white, etc., and usually contain 100% of component (a).
It is added in an amount of 0.1 to 200 parts by weight. In addition, the plasticizer is usually 1 part by weight per 100 parts by weight of component (a).
The plasticizer used includes dioctyl phthalate, dibutyl phthalate, tricresyl phosphate, partially hydrogenated terpene, and chlorinated diphenyl.

Next, examples of the present invention will be shown. In the text, parts mean parts by weight.
% indicates weight %. Note that the present invention is not limited to the examples.

[Example 1] 100 parts of polyether polyol (Efsenol 2020, manufactured by Asahi Glass Co., Ltd.), 35 parts of 4,4'-diphenylmethane diisocyanate polymer (Sumidur 44, V-20, manufactured by Sumidur Bayer Urethane) and hydrogenated xylylene diisocyanate ( Takenate 600, Takeda Pharmaceutical Co., Ltd.) 13
The mixture was reacted at 80° C. for 2 hours to obtain a urethane prepolymer [component (a)] containing 9.2% of free isocyanate groups, which was used as a main component.

Polyether polyol [Efcenol 45ONE,
1ljl Glass: 28 parts of component (b), 33.0 parts of component (d), diethylenetriamine, 30.3 parts of component (C), and dibutyl laurate [(
A mixture of 0.05 part of component e) was used as a curing agent.

[The active hydrogen of the amino group of the component (d) is 6.5 equivalents per equivalent of the active hydrogen of the component (C). ] Next, the base agent and the curing agent were mixed at room temperature uniformly at a weight ratio of 100:23 to obtain an adhesive composition. The viscosity of this adhesive composition at the initial stage of mixing was 500,000 CPS or less.

A shear test piece was prepared by bonding a humidified SMC board in an environment of 30° C. and 95% RH with the adhesive composition. When this was subjected to shear failure, the shear failure strength was 70 kg/cJ, resulting in material failure of SMC, and no foaming of the adhesive layer was observed.

In this example, the total amount of active hydrogen that can react with the isocyanate groups of components (b), (c), and (d) per equivalent of free isocyanate groups of component (a) is 1.
3 equivalents, and the total active hydrogen of the amino groups in components (c) and (d) is 0.4 equivalents per equivalent of free isocyanate groups in component (a).

[Example 2] A curing agent was prepared in the same manner as in Example 1 except that 30.44 parts of component (C) was used in place of diethylenetriamine in Example 1 and pentaethylenehexamine was used. Here, the isocyanate group of component (a), component (b), component (c), and (d
) The equivalent ratio of active hydrogen capable of reacting with the isocyanate group of the component is the same as in Example 1.

This was mixed with the base resin obtained in Example 1 at a weight ratio of 100:23 in the same manner as in Example 1, and an adhesive composition was used to adhere humidified SMC in the same manner as in Example 1, and a shear test was conducted. . As a result, no foaming was observed, and the shear fracture strength was 72 kg/d, resulting in material failure of SMC.

[Example 3] In place of monoethanolamine in Example 1, jetanolamine [38.00 parts of component (d)] was used, and 16 others were used as a curing agent in the same manner as in Example 1.

In this example, the isocyanate group 1 of component (a)
Per equivalent, the total amount of active hydrogen that can react with the isocyanate groups of component (b), component (c), and component (d) is 1
．． 4 equivalents, and the total active hydrogen of the amino groups of components (c) and (d) is 0.3 equivalent per equivalent of the isocyanate group of component (a), and the active hydrogen of component (c) The active hydrogen of the amino group in component (d) is 5 per equivalent.
．． 1 equivalent. This curing agent was mixed with the main resin obtained in Example 1.
An adhesive composition mixed in the same manner as in Example 1 at a weight ratio of 00:24 was used to adhere humidified SMC in the same manner as in Example 1, and a shear test was performed. As a result, no foaming was observed, and the shear fracture strength was 69 kg/cm? This resulted in material destruction of the SMC.

[Comparative Example 1] An adhesive composition was obtained in the same manner as in Example 1 except that 2.5 parts of diethylene l-heliamine and 6.0 parts of monoethanolamine (component (C)) were used in Example 1. .

The viscosity of the adhesive composition at the initial stage of mixing was as high as 1,000,000 CPS or more, and it generated a lot of heat and hardened before being pressed.

In addition, in this comparative example, the total active hydrogen of the amino groups of the component (c) and the component (d) per equivalent of the isocyanate group of the component (a) is 0.95 equivalent.

[Comparative Example 2] The monoethanolamine used in Example 1 was changed to 1.0 part, and the other conditions were the same as in Example 1. The adhesive foamed and became spongy. In this case, the total amount of active hydrogen in the amino groups of component (c) and component (d) per equivalent of isocyanate group in the main agent is 0.17 mol.

[Comparative Example 3] An adhesive composition was obtained in the same manner as in Example 1, except that 1.5 parts of diethylenetriamine was used in Example 1.

The mixture of main agent and curing agent has a high viscosity of 800,000 CPS.
I couldn't crimp it.

In addition, in this comparative example, per equivalent of active hydrogen of component (C),
The active hydrogen of the amino group in component (d) is 1.3 equivalents.

[Comparative Example 4] An adhesive composition was obtained in the same manner as in Example 1 except that the monoethanolamine of Example 1 was used in an amount of 5.0 parts.

The mixture of the base agent and the curing agent initially generated heat and started curing, but the subsequent curing was slow and the mixture foamed and became spongy. In this comparative example, the active hydrogen of the amino group of the component (d) was 103 g equivalent per 1 equivalent of the active hydrogen of the component (c).

<Effects of the Invention> The adhesive composition of the present invention has a low viscosity at the initial mixing stage, good workability, high adhesive strength, and can suppress foaming due to moisture, and is suitable for automobiles, ships, and construction. It can be suitably used for adhesion of FRP, wood, inorganic materials, etc. used in applications such as objects.

Claims (1)

[Claims] (a) Urethane prepolymer having two or more isocyanate groups, (b) Polyhydroxy compound having two or more OH groups, (c) Polyamine compound having two or more NH_2 groups , (d) a monoamine compound having a functional group capable of reacting with an NH_2 group or an isocyanate group other than the NH group, and (e) a curing catalyst, the adhesive composition comprising (b) component, (c) component, and The total number of active hydrogens in component (d) that can react with isocyanate groups is (a)
0.8 to 1.5 equivalents per equivalent of isocyanate group in component (c) and component (d), and the total of active hydrogens possessed by NH_2 groups and NH groups in component (c) and component (d) is per equivalent of isocyanate group in component (a). 0.2 to 0.9 equivalent, and (d
) The NH_2 group of the component and the active hydrogen contained in the NH group are (
c) 2.1 to 1 equivalent of active hydrogen of NH_2 group of component
An adhesive composition having an equivalent weight of 9.0.