JPH09255754A - Curable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a curable compsn. which is free from residual surface tack when cured by compounding a thiolated polymer, a polyisocyanate, and a levelling agent and/or an antifoaming agent for a coating material. SOLUTION: 100 pts.wt. polymer having a number-average mol.wt. of 600-200,000 and at least two thiol groups in the molecule is compounded with a polyisocyanate as the curative in a molar ratio of the isocyanate groups to the thiol group of the polymer of 0.5-4.0 and then compounded with 0.01-5 pts.wt. levelling agent and/or antifoaming agent for a coating material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable composition, and more particularly to a curable composition that is free from residual tack on the surface of a cured product and is suitable for use as a sealing material.

[0002]

2. Description of the Related Art A polymer containing two or more thiol groups in one molecule is easily cured when mixed with an oxidizing agent, and the thiol group easily reacts with an epoxy group, an isocyanate group or the like to increase the molecular weight. From sealing materials, paints,
Widely used for adhesives.

Examples of such a thiol group-containing polymer include a polysulfide polymer described in US Pat. No. 2,466,963 and a polysulfide polyether polymer described in Japanese Patent Application Laid-Open No. Hei 4-363325 filed by the present applicant. You.

In Japanese Patent Application Laid-Open No. 52-125563, the above-mentioned polysapphidide polymer is further disclosed.
In No. 21, there is proposed a curable composition suitable for a sealing material, which has a small amount of foaming, good weather resistance, and a white cured product can be easily obtained by curing the polysulfide polyether polymer and an isocyanate compound. It was

However, these curable compositions have a problem in that after curing, a large amount of tack remains on the surface of the cured product.

[0006]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to cure by reaction of a polymer having two or more thiol groups in one molecule with a polyisocyanate compound having two or more isocyanate groups in one molecule. The present invention provides a curable composition which is useful as a building sealant having no residual tack on the surface of the cured product.

[0007]

As a result of earnest research in view of the above object, the present inventors have found that a polysulfide polymer and / or a polysulfide polyether polymer, a compound having two or more isocyanate groups in one molecule, A curable composition characterized by having a predetermined amount of a coating leveling agent and / or a paint defoaming agent has been found to have no residual tack on the surface of the cured product, and the present invention has been conceived.

That is, the curable composition of the present invention comprises:
(A) a polymer having two or more thiol groups in one molecule, and (b) a polyisocyanate compound having two or more isocyanate groups in one molecule as a curing agent,
(C) A curable composition comprising (1) a leveling agent for paints and / or (2) an antifoaming agent for paints.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

[Polymer having two or more thiol groups in one molecule]: The polymer having two or more thiol groups in one molecule in the curable composition of the present invention is an ether bond, a thioether bond or a disulfide bond. It may have a urethane bond and an ester bond.

Preferred examples of such a polymer having two or more thiol groups in one molecule include JP-B-47-
No. 48279, polyoxyalkylene polyols described in U.S. Pat.
Polymer captan described in JP-A-3389. Other known compounds include thiol-terminated liquid polymers described in U.S. Pat. No. 3,923,748, and thiol-terminated liquid polymers of liquid thioethers described in U.S. Pat. No. 4,366,307. Can be
Furthermore, particularly preferred are the polysulfide polyether polymers and polysulfide polymers described below.

The number average molecular weight of such a polymer having two or more thiol groups in one molecule is usually 100 to 20.
000, preferably 400 to 100,000.

[Polysulfide Polyether Polymer]: The polysulfide polyether polymer in the second curable composition of the present invention has (A)-(R ₁ O) _{n in the} main chain.
-(Wherein, R ₁ is an alkylene group having 2 to 4 carbon atoms, n is an integer of 6 to 200), and (a)-(C ₂ H ₄ OCH ₂ OC ₂ H ₄ -S _X -)-and-(CH ₂ CH (OH) CH _2-
S _X) -. (Where, X is contains a structural unit represented by is an integer from 1 to 5), and the end, _{(c) -C 2 H 4 OCH 2 OC} 2 H 4 -
Those having a SH and / or -CH ₂ CH (OH) thiol groups represented by CH ₂ -SH.

In the polysulfide polyether polymer, the polyether portion of (a) and the structural unit shown in (a) may be bonded in an arbitrary sequence. The proportion of the (A)-(R ₁ O) _n- component is 2 to 95% by weight, and the (B) (C ₂ H ₄ OCH ₂ OC ₂ H ₄ -S _X ) component is 3 to 70% by weight. %
It is preferable that the content of the (CH ₂ CH (OH) CH ₂ —S _X ) component is 1 to 50% by weight. The number average molecular weight of this polysulfide polyether polymer is usually 600 to 200,000, preferably 800 to 50,000.

Such a polysulfide polyether polymer can be produced by a method described in, for example, JP-A-4-363325.

[0016] [polysulfide polymer -: polysulfide polymer in the third curable composition of the present invention, in the main chain _{(d) - (C 2 H 4 OCH} 2 OC 2 H 4 -
Sx)-(however, x is an integer of 1 to 5), and (o) -C ₂ H ₄ O at the end.
It has a thiol group represented by CH ₂ OC ₂ H ₄ —SH. This polysulfide polymer has fluidity at room temperature and usually has a number average molecular weight of 100 to 200,0.
00, preferably 400 to 50,000.

Preferred examples of such polysulphide polymers are described in US Pat. No. 2,466,963.

[Polyisocyanate compound having two or more isocyanate groups in the molecule]: The compound (b) having two or more isocyanate groups in the molecule of the present invention includes an organic polyisocyanate compound and / or an active hydrogen-containing compound. A urethane prepolymer obtained by reacting a compound with an organic polyisocyanate compound is preferable.

As the organic polyisocyanate compound,
Specific examples include tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate (crude MDI), xylylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, and the like.

As the active hydrogen-containing compound, a hydroxyl group-terminated polyester, a polyvalent polyalkylene ether, a hydroxyl group-terminated polyurethane polymer, an acrylic polyol having a hydroxyl group introduced into an acrylic copolymer, a hydroxyl group-terminated polybutadiene, a polyvalent polythioether, a polyacetal, An aliphatic polyol, an alkane including an alkylenethiol having two or more SH groups, an alkene and an aliphatic thiol, a polysulfide polymer having an SH group at the terminal,
Siamines, including aromatic, aliphatic and heterocyclic diamines, and the like, and mixtures thereof.

As the urethane prepolymer, the above-mentioned active hydrogen-containing compound and organic polyisocyanate compound,
It is obtained by reacting under the condition of an excess of isocyanate compound.

In the present invention, the molar ratio of the isocyanate group in the compound (b) to the thiol group in the above-mentioned (a) thiol group-containing polymer (isocyanate group / thiol group) is 0.5 to 4. Blend so that it will be 0. If the molar ratio is less than 0.5, the composition does not have a sufficiently high molecular weight, which is not preferable. On the other hand, if it exceeds 4.0, the cured product becomes hard and brittle, which is not preferable. A more preferred molar ratio is 0.7 to 3.0.

[Leveling agent for paints, defoaming agent for paints]:
The coating leveling agent and coating defoaming agent of the present invention may be a leveling agent and a defoaming agent generally added to coatings,
Acrylic polymers, vinyl polymers, silicone polymers, and mineral polymers are available.

[0024] Above all, leveling agents for silicone-based paints
Defoaming agents for paints are preferred, and alkyl / aralkyl-modified silicone polymers are more preferred.

The leveling agent for paints and / or the defoaming agent for paints may be contained in an amount of 0.01 to 5 parts by weight per 100 parts by weight of the polymer (a) having two or more thiol groups in one molecule. preferable.

[Other Compounds]: The curable composition of the present invention contains calcium carbonate, talc, clay for the purpose of further improving economy, workability in applying the composition and physical properties after curing. An acidic substance can be added as a filler such as titanium oxide or silica, a plasticizer, a curing catalyst and a curing retarder.

As the curing catalyst, a tertiary amine, an organometallic compound or the like is used.

As the tertiary amine, monoamines, diamines, triamines, polyamines, cyclic amines,
There are alcohol amines, ether amines and the like, and specific examples are triethylamine, N, N-dimethylcyclohexylamine, N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-. Tetramethylpropane-1,3-diamine, N, N, N ′, N′-tetramethylhexane-1,6-diamine, N, N,
N ', N ", N" -pentamethyldiethylenetriamine, N, N, N', N ", N" -pentamethyldipropylenetriamine, tetramethylguanidine, N, N-dipolyoxyethylenestearylamine, N, N -Dipolyoxyethylene tallow alkylamine, triethylenediamine, N, N'-dimethylpiperazine, N-methyl-
N '-(2 dimethylamino) -ethylpiperazine, N-
Methylmorpholine, N-ethylmorpholine, N-
(N ′, N′-dimethylaminoethyl) -morpholine,
1,2-dimethylimidazole, dimethylaminoethanol, dimethylaminoethoxyethanol, N, N,
N'-trimethylaminoethylethanolamine, N-
Methyl-N ′-(2-hydroxyethyl) -piperazine,
N- (2hydroxyethyl) -morpholine, bis- (2
Dimethylaminoethyl) ether, ethylene glycol bis- (3dimethyl) -aminopropyl ether, and the like. Among them, an N, N-dipolyoxyethylene alkylamine compound is preferable because the residual tack of the cured product is small. Specific examples include N, N-dipolyoxyethylene stearylamine, N, N-dipolyoxyethylene tallow alkylamine, and the like. Further, a hindered amine type light stabilizer is also preferable because the residual tack is small. These three
Two or more secondary amines may be used.

The organometallic compounds include organotin compounds, organomercury compounds, organolead compounds, and the like. Specifically, tin octylate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin mercaptide, dibutyltin thiocarboxyl. Examples thereof include phthalate, dibutyltin dimaleate, dioctyltin mercaptide, dioctyltin thiocarboxylate, phenylmercuric propionate and lead octenoate. Among them, an organic tin compound which is less affected by discoloration and the like is preferable, and more preferable are dialkyltin mercaptide, dialkyltin dicarboxylate, dialkyltin bis (dicarboxylic acid monoalkyl ester) salt, dialkyltin (dicarboxylic acid) salt and the like. .

As the acidic substance, organic acids such as citric acid, stearic acid, and 2-ethylhexanoic acid are preferable.

Generally, by curing a polymer having two or more thiol groups in one molecule with a compound containing two or more isocyanate groups in one molecule, there is little foaming and good weather resistance, and a white type Since a cured product can be easily obtained, a curable composition suitable for a sealing material can be obtained.
However, these compositions have a problem that a large amount of residual tack remains on the surface of the cured product.

In the present invention, a polymer having two or more thiol groups in one molecule and a compound having two or more isocyanate groups in one molecule are used together with a predetermined amount of a coating leveling agent and / or a coating decoloring agent. By adding the foaming agent, residual tack on the surface of the cured product is eliminated.

[0033]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Synthesis Example 1 Bifunctional polypropylene glycol obtained by adding propylene oxide to propylene glycol (OH value: 55.3 mgKOH / g) 800
g, 87.7 g of epichlorohydrin, and 1.0 g of stannic chloride pentahydrate were charged into a reaction vessel, and the temperature was adjusted to 80 to 90 ° C.
For 3 hours. In addition, polysulfide polymer
(Toray Thiokol Co., Ltd., trade name "Thiocol LP5
5 ″) 887.7 g were added and mixed, then 76 g of sodium hydrosulfide (purity 70%) was added, and the mixture was stirred at 80 ° C. for 2 hours. Thereafter, 7.1 g of a 50% aqueous solution of citric acid was added, and the mixture was added for 15 minutes. After stirring and dehydration, the salt was removed to obtain a pale yellow transparent polymer having a mercaptan content of 2.0% by weight and a viscosity of 80 poise (25 ° C.).

[Example 1] to [Example 7] The polymer of Synthesis Example 1 was blended with a plasticizer, a filler and a curing catalyst in the proportions shown in Table 1 to obtain a main component. To 390 parts by weight of this base material, 64 parts by weight of a urethane prepolymer (isocyanate content 4.2% by weight) obtained by adding xylene diisocyanate to polypropylene glycol, and an additive (c) of the type and amount shown in Table 2 are added. Mixed. The obtained mixture was poured into a container having an inner diameter of 30 mm and a depth of 5 mm, the weight was measured (weight ag), and the exposed surface was immediately sprinkled with 30 to 50 mesh silica sand. With this surface facing down, excess silica sand that had not adhered was dropped and the weight was measured (weight bg). In addition, the mixture is poured into a container in the same manner as above, and the temperature is kept at 20 ° C. 60
% Curing for 5 days before curing, and the weight (weight c
g) and the weight after adhesion (weight dg) were measured, and the residual tack ratio (%) was calculated by the equation (1). The results are shown in Table 3.

Remaining tack ratio (%) = ((d−c) / (ba)) × 100 (1) Formula [Comparative Example 1] As a comparative example, a synthetic example is used in the case where the additive (c) is not added. In Example 1, the plasticizer, the filler, and the curing catalyst were added to the polymer No. 1 in the proportions shown in Table 1.
The same test as that of ~ 5 was performed. Table 3 shows the results.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

[0040]

INDUSTRIAL APPLICABILITY As described in detail above, according to the present invention, a polymer having two or more thiol groups in one molecule and a compound having two or more isocyanate groups in one molecule are used in a predetermined amount for coating. By adding the leveling agent and / or the defoaming agent for paint, residual tack on the surface of the cured product is eliminated. Such a curable composition is suitable for use as a sealing material, an adhesive or the like.

Claims (7)

[Claims] 1. A polymer having (a) two or more thiol groups in one molecule, (b) a polyisocyanate compound having two or more isocyanate groups in one molecule as a curing agent, and (c) ( A curable composition comprising 1) a leveling agent for paints and / or (2) an antifoaming agent for paints. 2. The curable composition according to claim 1, wherein
Wherein (a) a polymer having two or more thiol groups in one molecule, in the main chain _{(A) - (R 1 O) n} - ( where, R ₁
Represents an alkylene group having 2 to 4 carbon atoms, and n represents an integer of 6 to 200. ) And a polyether moiety represented by (b)-(C
₂ H ₄ OCH ₂ OC ₂ H ₄ -S _X )-, and-(CH ₂
CH (OH) CH ₂ —S _X ) — (where x is an integer of 1 to 5) and a terminal of (u) —C ₂ H ₄ OCH. ₂ OC ₂ H ₄ -SH and /
Alternatively, the curable composition is a polysulfide polyether polymer having a thiol group represented by —CH ₂ CH (OH) CH ₂ —SH. 3. The curable composition according to claim 1, wherein
The polymer (a) having two or more thiol groups in one molecule is (d)-(C ₂ H ₄ OCH ₂ OC) in the main chain.
₂ H ₄ -Sx)-(where x is an integer of 1 to 5)
A structural unit represented by
A curable composition, which is a polysulfide polymer having a thiol group represented by ₂ H ₄ OCH ₂ OC ₂ H ₄ —SH. 4. The curable composition according to claim 1, wherein (c) (1) the coating leveling agent and / or (2) the coating defoaming agent is (3) a silicone polymer and / or (4) A curable composition comprising an acrylic polymer and / or (5) a vinyl polymer. 5. The curable composition according to claim 4, wherein (c) the silicone-based polymer is (6) an alkyl-aralkyl-modified silicone polymer. 6. The curable composition according to claim 1, wherein
The molar ratio of the isocyanate group in the compound (b) having two or more isocyanate groups in one molecule and the thiol group in the polymer (a) having two or more thiol groups in one molecule (isocyanate Group / thiol group) is 0.5 to 4.0. 7. (c) (1) a coating leveling agent and / or (2) a coating defoaming agent (a) with respect to 100 parts by weight of a polymer having two or more thiol groups in one molecule, 0.
The curable composition according to claim 1, wherein the curable composition is contained in an amount of 01 to 5 parts by weight.