JPH0333179B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composition that can be cured at room temperature and can be used in a wide range of fields such as adhesives, paints, cast products, fiber-reinforced plastics, and the like.

It is known that among resins that can be cured at room temperature, there are those that are easy to cure, and those that require temperature and time to be cured, and there are considerable differences in the difficulty of curing. For example, it is easy to cure unsaturated polyester resins, but when curing epoxy resins with amines, it is not only difficult to control the curability by increasing or decreasing the amount of amine as a curing agent, but also the viscosity In addition to being expensive, the problems of skin irritation and toxicity of amines remain.

The present inventors developed poly(meth)acrylate and polythiol compounds in order to maintain the excellent physical properties found in epoxy resins while improving their handling properties, i.e., the difficulty in controlling their curing properties and their high viscosity. We have been conducting research on so-called polyene-polythiol type resins, but this type of resin is difficult to cure in terms of high temperature curing using organic peroxides and cationic curing using cationic catalysts.
Due to the conventional wisdom that it would hardly exhibit physical properties sufficient for practical use, research and practical application have only been attempted in terms of photocuring.

Light curing is certainly an advantageous method, and when it is applied there is no need to adopt other curing methods, but in cases where light curing is difficult to apply, e.g. for bonding. Therefore, it is essential to establish a different curing system, a type of resin that hardens easily at room temperature.

From this point of view, the present inventors further investigated the room-temperature curing method for polyene-polythiol type resins and, quite unexpectedly, discovered a curing system that seems to be a type of redox reaction using a combination of an organic peroxide and a metal compound. The inventors have found that by applying the above-mentioned method, room temperature curing can be carried out very easily and in some cases in an extremely short time, and the present invention has been completed.

That is, the present invention provides (1) poly(meth)acrylates having two or more acryloyl groups or methacryloyl groups in one molecule, (2) polythiol compounds having two or more thiol groups in one molecule, (3 The present invention relates to a composition that is curable at room temperature and is comprised of (4) an organic peroxide and (4) a metal compound.

In general, curing of poly(meth)acrylates containing acryloyl or methacryloyl groups that do not contain styrene tends to be significantly more difficult than curing of styrene-containing unsaturated polyester resins or vinyl ester resins, and organic peroxides to This discovery was unexpected because it is common knowledge that curing systems that combine metal compounds do not cure, and that a combination of acyl peroxide and aromatic tertiary amine is used.

One of the fundamental differences between the curing of the poly(meth)acrylate and polythiol compound type resin of the present invention and the curing of conventional radical-curable resins, such as unsaturated polyester resins and vinyl ester resins, is that Curing resins do not show any curing accelerating ability, or conversely, curing systems consisting of organic peroxides and metal compounds that inhibit polymerization show significant curing for poly(meth)acrylate and polythiol compound type resins. It can be mentioned that it has a promoting effect.

Examples of such metal compounds include metals such as nickel, chromium, and tin.

These facts also indicate that the mechanism when poly(meth)acrylate and polythiol compound type resins are cured with organic peroxides and metal compounds is different from that of conventional radical-curable resins. Conceivable. In particular, the polythiol compound is used to form one component of the cured resin, and is not used simply as a chain transfer agent.

The poly(meth)acrylate used in the present invention is produced by copolymerizing a vinyl monomer and an unsaturated alcohol to synthesize a polymer having a hydroxyl group in the side chain, and then reacting the polymer with an unsaturated isocyanate having a (meth)acryloyl group. , is a poly(meth)acrylate having two or more acryloyl groups or methacryloyl groups in one molecule, in which the hydroxyl group of the polymer side chain is converted into a (meth)acryloyl group via two urethane bonds.

Desired vinyl monomers for copolymerizing with unsaturated alcohols to form polymers having hydroxyl groups in side chains include, for example, styrene, chlorostyrene, vinyltoluene, acrylic esters (methyl-, ethyl-, butyl- , 2-ethylhexyl, octyl, etc.), methacrylic acid esters (methyl, ethyl, propyl, etc.)
butyl, isobutyl, tertiary, butyl, 2-ethylhexyl, laurylbenzyl, cyclohexyl, tetrahydrofurfuryl, etc.), vinyl acetate, vinyl propionate, vinyl versatate, etc., and acrylic for modification. Acid, methacrylic acid can also be used.

Typical examples of unsaturated alcohols for forming polymers with hydroxyl groups in side chains include:
Examples include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, and allyl alcohol.

An unsaturated isocyanate having a (meth)acryloyl group is converted into an unsaturated monoalcohol having an acryloyl group or a methacryloyl group, and a diisocyanate is added so that the molar ratio of hydroxyl group to isocyanate group is substantially 1:1. It is synthesized by reacting as follows.

Examples of unsaturated monoalcohols include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate.

Examples of the diisocyanate include 2,4-tolylene diisocyanate, mixed isocyanate of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, and 1,6-hexocyanate. Examples include methylene diisocyanate, 1,5-naphthylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and hydrogenated xylylene diisocyanate.

Examples of the polythiol compound used in the present invention include compounds having two or more thiol groups in one molecule and prepolymers. Representative examples of compounds include esterification products of thioglycolic acid or thiopropylenic acid and polyhydric alcohols. Specific examples include hexanediol dithiglycolate, hexanediol thiopropylate, trimethylolpropane trithioglycolate, trimethylolpropane trithiopropionate, pentaerythritate tetrathioglycolate, pentaerythritate tetrathiopropionate, etc. can be given. In addition, thiobisphenol A, isocyanuric acid (3-mercaptopropyl) ester, triazine trithiol,
Thiopentaerythrite and the like can also be used.

As prepolymers, thioalkyd resins,
For example, trimethylolpropane ~ phthalic anhydride ~
Examples include alkyd resins having thiol groups obtained by esterifying mercaptopropionic acid.

The mixing ratio of poly(meth)acrylate and polythiol compound is preferably such that the molar ratio of (meth)acryloyl group to thiol group is 1:1, but the above molar ratio may be changed depending on the purpose. You may change it. For example, when the composition of the present invention is used as an adhesive, a polythiol compound may be added so that some thiol groups remain, and if the composition of the present invention can be post-cured, Poly(meth)acrylate may be added in excess so that (meth)acryloyl groups remain.

Examples of the organic peroxide used in the present invention include ketone peroxides such as methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, cyclohexanone peroxide, and 1,1-bis(t-butyl peroxide).
Peroxyketanols such as 3,3,5-trimethylcyclohexane, t-butyl hydride peroxide, cumene hydride peroxide, diisopropylbenzene hydroperoxide, paramethane hydroperoxide, 1,1,3,
3. Hydroperoxides such as tetramethylbutylhydroperoxide, peroxy esters such as t-butylperoxybenzoate, t-butylperoxylaurate, etc. Two or more of these organic peroxides may be used in combination.

The amount of organic peroxide used is in the range of 0.1 to 10 parts by weight based on 100 parts by weight of the mixture of poly(meth)acrylate and polythiol compound. If the amount of organic peroxide used is less than 0.1 part by weight, it will be difficult to completely cure, while if the amount of organic peroxide used is more than 10 parts by weight, the physical properties of the cured product will deteriorate, which is not preferable.

Examples of the metal compound used in the present invention include those that are soluble in organic solvents or poly(meth)acrylates and/or polythiol compounds, preferably those that are soluble in organic solvents and are soluble in poly(meth)acrylates and/or polythiol compounds. Examples include organic acid salts of metals having a valence of two or more and chelate compounds that are soluble in the polythiol compound.

Metals that can be used in the present invention include copper, cobalt, nickel, manganese, vanadium, chromium,
Zirconium, iron, palladium, molybdenum,
Examples include tin, cerium, aluminum, etc.

These metals are utilized as metal salts or chelate compounds of organic acids such as naphthenic acid, octylic acid, lauric acid, oleic acid, rosin acid, and the like. However, since organic acid salts of vanadium are unstable and have poor storage stability, it is preferable to use them in a stabilized form by dissolving a chelate compound such as vanadium acetylacetonate in an acidic alkyl phosphate ester. This tendency is also observed in organic acid salts of molybdenum and palladium, so it is preferable to use them in the same form as acetylacetonate of vanadium.

The amount of the metal compound to be used cannot be determined unconditionally as there are significant differences depending on the type of metal, but in general, the amount of the metal compound to be used per 100 parts by weight of the mixture of poly(meth)acrylate and polythiol compound is
The amount is from 1 ppm to 5 parts by weight, preferably from 10 ppm to 1 part by weight. If the amount of the metal compound used is less than 1 ppm, the curing accelerating effect will not be sufficient. On the other hand, if the amount of the metal compound used is more than 5 parts by weight, no curing will be observed due to the increased amount.

The organic peroxide and the metal compound may be added to the mixture of the poly(meth)acrylate and the polythiol compound in sequence, or the organic peroxide and the metal compound may be added separately and then mixed together before use. good. That is, an organic peroxide may be added to the poly(meth)acrylate component, a metal compound may be added to the polythiol compound component, and both components may be mixed at the time of use. At this time, the organic peroxide and the metal compound may be added in the opposite order.

It goes without saying that reinforcing materials, fillers, colorants, mold release agents, and the like may be appropriately used in the composition of the present invention in order to meet the required physical properties.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Synthesis of side chain unsaturated bond type polymer (C) 300 g of ethyl acetate and 3 g of azobisisobutyronitrile were placed in a separable flask equipped with a stirrer, a reflux condenser, a gas introduction tube, a thermometer, and a dropping funnel. A monomer mixture of 416 g of styrene and 144 g of 2-hydroxypropyl methacrylate was added dropwise under the boiling point of ethyl acetate in a nitrogen gas stream.

After the dropwise addition was completed, reflux was continued for 12 hours to complete the polymerization.

After adding 0.25 g of hydroquinone to stop the polymerization, the temperature was lowered to 60°C, and an adduct of 1 mol of 2,4-tolylene diisocyanate and 1 mol of 2-hydroxyethyl methacrylate (stirrer, reflux condenser, thermometer, 174 g of 2,4-tolylene diisocyanate and 0.2 g of dibutyltin dilaurate were placed in a separable flask (No. 1) equipped with a dropping funnel, heated to 60°C, and 130 g of 2-hydroxyethyl methacrylate (0.13 g of hydroquinone)
) was added dropwise, and after the dropwise addition was completed, the reaction was carried out at 60°C for 3 hours. As a result of infrared analysis, the absorption of hydroxyl groups completely disappeared, indicating that it is a pale yellow acrylate having isocyanate groups. ) was added and stirred under heating at 60°C for 5 hours in the air. As a result of infrared analysis, absorption of hydroxyl groups and isocyanate groups completely disappeared.

864 g of ethylene glycol dimethacrylate was added and ethyl acetate was distilled off under reduced pressure of 500 mmHg to obtain a side chain unsaturated bond type polymer (C) having a Hazen color number of 450 and a viscosity of 39 poise.

50 g of isocyanuric acid (3-mercaptopropyl) ester and 2 g of paramenthane hydroperoxide were mixed with 50 g of polymer (C), and 0.2 g of an acidic butyl phosphate solution of vanadium acetylacetonate (1% V) was added to this. .

Gelation occurred after about 15 minutes, followed by an exotherm reaching a maximum exotherm temperature of 139°C.

The cured resin is yellowish brown and hard, with a completely hardened surface and a Rockwell hardness (M scale) of 108.
It came out.

In addition, in the above method, isocyanuric acid (3
-Mercaptopropyl)ester except for the same formulation required about 5 hours to gel, and showed almost no heat generation, and the surface of the solidified resin was so sticky that it was impossible to measure its physical properties.

Claims (1)

[Claims] 1 (1) After copolymerizing a vinyl monomer and an unsaturated alcohol to synthesize a polymer having a hydroxyl group in the side chain, an unsaturated isocyanate having a (meth)acryloyl group is reacted to form a polymer. Poly(meth)acrylate having two or more acryloyl or methacryloyl groups in one molecule, in which the hydroxyl group in the side chain is converted into a (meth)acryloyl group via two urethane bonds, (2) 1 molecule A composition curable at room temperature, which contains a polythiol compound having two or more thiol groups, (3) an organic peroxide, and (4) a metal compound.