JP2001114858A - Curable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a curable composition capable of giving coating film with good surface decorativeness, high mechanical strength, high adhesion to sub strate, and high weatherability as well. SOLUTION: This curable composition comprises a hydroxy-bearing vinyl polymer, a polyisocyanate and a water absorbent; wherein the equivalent ratio of the isocyanate group in the polyisocyanate to the hydroxy group in the vinyl polymer is <=0.9; the hydroxy-bearing vinyl polymer is preferably such as to be obtained by continuous polymerization at 150-350 deg.C and 500-20,000 in number-average molecular weight. Furthermore, it is desirable that this composition is compounded with a low-molecular weight polydydric alcohol for the purpose of improving the mechanical properties of the cured coating film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable composition which can be used as a solvent-free thick coating which can be cured at room temperature and which is useful in the field of coating concrete, metal, plastic and the like.

[0002]

2. Description of the Related Art Epoxy resin and polyurethane paints have been widely used for the purpose of protecting the surface of concrete, metal, plastic, and the like and for providing cosmetic properties. Among them, epoxy resin-based paints are excellent in adhesion to substrates, heat resistance and chemical resistance, but are inferior in weather resistance, abrasion resistance, impact resistance and the like.

[0003] As a coating composition excellent in impact resistance and abrasion resistance, which is a drawback of such an epoxy coating composition, there is a polyurethane coating composition. In a commonly used polyurethane-based paint, a polyether polyol or a polyester polyol is used as a polyol component as a raw material. Of these, polyurethanes using polyether polyols have the drawback that their coatings are easily degraded by heat and photo-oxidation and corroded by acids. Further, polyurethane using a polyester polyol has a disadvantage that the coating film is easily deteriorated by hydrolysis. Therefore, both are insufficient in terms of weather resistance.

[0004] For applications requiring weather resistance, an acrylic urethane-based resin having a polyol component of poly (meth) acrylate polyol having the above-mentioned disadvantages improved is used as polyurethane. However, conventional poly (meth) acrylate polyols have a large molecular weight and do not have fluidity at room temperature. Therefore, it is necessary to dilute the composition with a solvent in order to impart appropriate fluidity. in this case,
After the application, the solvent evaporates and the skin becomes thin, and only a cured coating film having a thickness of several tens to 100 μm is obtained at a time. When considering the environmental aspect, the composition usually contains 40 to 60% by weight of a solvent, which is almost completely discharged into the air after drying. In recent years, there have been concerns about the effects of organic solvents and cleaning solvents used in various industries, including the coatings field, on air pollution and organisms due to their release into the atmosphere. Paints have been demanded.

[0005] In order to solve these problems, the present inventors have made it possible to apply a thick coating to a two-part curable composition comprising a liquid acrylic polyol and a polyisocyanate, and to improve weather resistance, chemical resistance and the like. An excellent solvent-free paint has been proposed (Japanese Patent Application Laid-Open No. 10-17640). This two-part curable composition is a material which has significantly improved the weather resistance, hydrolysis resistance, and workability, which have been problems of polyurethane-based paints.

On the other hand, Japanese Unexamined Patent Publication (Kokai) No. 61-85479 discloses that a water absorbent is used in a metal pipe anticorrosion coating comprising a polyalkylene polyol, which is a polyether polyol, and a polyisocyanate compound to prevent foaming of the coating. It is disclosed that.

[0007]

The two-pack type curable compositions proposed by the present inventors have excellent properties as described above, but are sometimes used in compositions or in air. Moisture reacts with isocyanate groups in the curable composition to generate carbon dioxide gas. Foaming occurs when the coating film is cured under high humidity, which may worsen the cosmetic properties of the resulting coating film, reduce the film strength and adhesiveness, and the use may be restricted depending on the application. The present inventors have found that.

The anticorrosion paint for metal pipes described in JP-A-61-85479 is liable to deteriorate the polyalkylene polyol, which is a main component thereof, with respect to light such as ultraviolet rays. There was a problem that was bad. Furthermore, since the paint has a high ratio of isocyanate groups to hydroxyl groups, it foams when the coating film is cured under high humidity, and the cosmetic properties of the coating film may deteriorate, or the strength or adhesiveness may decrease. It also has problems.

The present invention has been made by focusing on the problems existing in the prior art as described above. The objective is to make the surface of the resulting film cosmetic, the strength of the film,
An object of the present invention is to provide a curable composition which can maintain good adhesion of a coating film to a substrate and has excellent weather resistance of the coating film.

[0010]

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted various studies, specified the ratio of hydroxyl groups and isocyanate groups present in the curable composition, and determined the ratio of The present inventors have found out that these problems can be solved by using a conventional water-absorbing agent, and have completed the present invention. That is, the curable composition of the present invention contains a vinyl polymer having a hydroxyl group, a polyisocyanate, and a water-absorbing agent, and the equivalent ratio of the isocyanate group to the hydroxyl group is 0.9.
It is the following.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. The curable composition of the present invention is characterized by using a vinyl polymer having a hydroxyl group as a main component, a polyisocyanate, and a water absorbing agent such that an equivalent ratio of an isocyanate group to a hydroxyl group is 0.9 or less. is there.

The vinyl polymer having a hydroxyl group is one in which the hydroxyl group undergoes a urethanization reaction with an isocyanate group in the polyisocyanate to form a cured product. Examples of the vinyl polymer include (meth) acrylates having a hydroxyl group (hereinafter, referred to as (meth) acrylates containing a hydroxyl group).
A copolymer of at least one type and at least one type of another monomer having an ethylenically unsaturated group (hereinafter, referred to as an ethylenically unsaturated monomer) is preferable. In this specification, acrylic and methacryl are collectively referred to as (meth) acryl.

As the hydroxyl group-containing (meth) acrylate, various ones can be used. For example, hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate and hydroxybutyl (meth) acrylate, and pentane Polyhydric alcohol mono- or poly (meth) acrylates such as erythritol tri (meth) acrylate and glycerin mono (meth) acrylate; and epoxides such as adducts of cyclohexene oxide with (meth) acrylic acid and (meth) acrylic acid. (Meth) acrylates having one or more hydroxyl groups in the molecule, such as adducts.

As the ethylenically unsaturated monomer, various ones can be used as long as they are other than the above-mentioned hydroxyl group-containing (meth) acrylate. For example, styrene, acrylonitrile, methacrylonitrile, vinyl acetate and those having no hydroxyl group ( (Meth) acrylate and the like. Specific examples of the (meth) acrylate having no hydroxyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, and 2-ethylhexyl (meth). Examples include acrylate, 2-ethoxyethyl (meth) acrylate, and isobornyl (meth) acrylate.

The above-mentioned hydroxyl group-containing (meth) acrylate and ethylenically unsaturated monomer are different from conventional polyalkylene polyols in that their polymers, ie, hydroxyl-containing vinyl polymers, are hardly deteriorated by light, Since it has excellent weather resistance, the weather resistance of a cured film obtained from the curable composition can be improved.

The vinyl polymer having a hydroxyl group preferably has a hydroxyl value of 10 to 400 mgKOH / g, more preferably 50 to 300 mgKOH / g. When the hydroxyl value is less than 10 mgKOH / g, the reaction with the polyisocyanate is insufficient, resulting in poor curing, and the resulting cured film tends to be poor in chemical resistance, abrasion resistance and tensile properties. Conversely, if it exceeds 400 mgKOH / g, the resulting coating tends to be brittle.

The vinyl polymer having a hydroxyl group preferably has a number average molecular weight of 500 to 20,000, more preferably 1,000 to 10,000. When the number average molecular weight is less than 500, the curable composition cannot be thickly applied to the substrate, or the cured film has poor flexibility. On the other hand, when it exceeds 20,000, the viscosity of the curable composition becomes high and the workability at the time of coating or the like becomes poor.

In the present specification, the number average molecular weight (hereinafter, referred to as the number average molecular weight)
The abbreviation of Mn if necessary) and the weight average molecular weight (hereinafter abbreviated as Mw if necessary) refer to the molecular weight measured by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent. It is the value converted to.

The vinyl polymer having a hydroxyl group preferably has a glass transition temperature (hereinafter, referred to as Tg) of -70 to 30 ° C, more preferably -60 to 20 ° C. When Tg is lower than -70 ° C, the strength of the obtained coating tends to be inferior. When Tg exceeds 30 ° C., the coating tends to be brittle.

The copolymer of a hydroxyl group-containing (meth) acrylate and an ethylenically unsaturated monomer may be prepared by a conventionally known method, for example, a bulk polymerization method, a solution polymerization method, an emulsion polymerization method or the like. Accordingly, it is produced by heating and stirring a hydroxyl group-containing (meth) acrylate and an ethylenically unsaturated monomer in the presence of a polymerization solvent, a radical polymerization initiator and a chain transfer agent.

In this case, the reaction temperature may be appropriately selected depending on the monomer used, the presence or absence and type of radical polymerization initiator, the presence or absence of a polymerization solvent, the boiling point, and the like.
Is appropriate. If the temperature is lower than 50 ° C., the molecular weight of the obtained polymer may be too large or the reaction rate may be slow. On the other hand, if the temperature is higher than 350 ° C., a decomposition reaction is generated and the reaction solution is colored. May be seen. When the polymerization is carried out at 150 to 350 ° C., a polymer having a target molecular weight can be easily obtained without using a radical polymerization initiator or a chain transfer agent or by using a small amount thereof. This is a preferable method because the weather resistance becomes good.

The radical polymerization initiator is not particularly limited, and examples thereof include an azo polymerization initiator and a peroxide polymerization initiator generally used in thermal polymerization. Examples of the azo polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile) and 2,2'-azobis (2,4-dimethylvalero). Nitrile) and the like. Examples of the peroxide-based polymerization initiator include hydrogen peroxide, di-t-butyl peroxide, benzoyl peroxide, and the like. The amount of the thermal polymerization initiator used is preferably 0.01 to 10 parts by weight based on 100 parts by weight of the total amount of the hydroxyl group-containing (meth) acrylate and the ethylenically unsaturated monomer.

The polymerization solvent is not particularly limited as long as it can dissolve the produced copolymer. For example, aromatic hydrocarbons such as toluene and xylene, ethyl acetate, butyl acetate, cellosolve acetate, methyl propylene glycol acetate, carbitol acetate and methyl propylene glycol acetate, acetate such as carbitol acetate and ethyl carbitol acetate, and And ketones such as acetone and methyl ethyl ketone. The amount of the polymerization solvent used is preferably such that the solid content concentration of the obtained copolymer is 10 to 90% by weight.

In particular, a method for continuous polymerization at 150 to 350 ° C. (hereinafter referred to as “high temperature continuous polymerization”) is to use a copolymer having a uniform molecular weight distribution, that is, a copolymer having Mw / Mn in the range of 1.2 to 3.0. It is preferable because it is easy to obtain and it is easy to obtain a good balance of the viscosity of the composition and the physical properties (strength, elongation, etc.) of the cured product.

As the high-temperature continuous polymerization method, JP-A-57-5
02171, 59-6207, 60-2150
A known method disclosed in each gazette such as No. 07 may be used. For example, a pressurizable reactor is filled with a solvent, and after a predetermined temperature is set under pressure, a monomer comprising a hydroxyl group-containing (meth) acrylate, an ethylenically unsaturated monomer, and, if necessary, a polymerization solvent is used. There is a method in which the body mixture is supplied to the reactor at a constant supply rate, and an amount of the reaction solution corresponding to the supply amount of the monomer mixture is withdrawn.

When a polymerization solvent is used, the solvent charged into the reactor before the start of the reaction and the polymerization solvent to be mixed with the monomer mixture may be the same or different. As the charged solvent or the polymerization solvent before the start of the reaction, the same solvents as those described above can be used, and glycols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol and tripropylene glycol,
These monoalkyl ethers, dialkyl ethers and the like can be used. The mixing ratio of the polymerization solvent is preferably 200 parts by weight or less based on 100 parts by weight of the monomer mixture.

Further, a radical polymerization initiator can be added to the monomer mixture, if necessary, and the same compounds as those described above can be used. When the thermal polymerization initiator is blended with the monomer mixture, the blending amount is as follows.
It is preferably 0.001 to 5 parts by weight based on 00 parts by weight.

The reaction pressure depends on the reaction temperature and the boiling point of the monomer mixture and the solvent used and does not affect the reaction, but may be any pressure that can maintain the reaction temperature. The residence time of the monomer mixture is preferably 2 to 60 minutes. If the residence time is less than 2 minutes, the reaction rate of the monomer may decrease, and if it exceeds 60 minutes, the productivity of the hydroxyl group-containing vinyl polymer may deteriorate.

The method of polymerizing at a temperature of 50 ° C. or higher and lower than 150 ° C. has an advantage that the equipment for producing the polymer can be relatively inexpensive. In this case, a monomer mixture consisting of a hydroxyl group-containing (meth) acrylate and an ethylenically unsaturated monomer can be polymerized at once, but a part of the monomer mixture is used as a polymerization solvent and radical polymerization. The polymerization method of adding the initiator to the reactor charged and initiating the reaction, and then dropping the remaining monomer mixture into the reaction solution, in order to reduce the molecular weight distribution of the resulting hydroxyl-containing vinyl polymer. preferable.

Next, the polyisocyanate reacts with a vinyl polymer having a hydroxyl group by urethanation to form a cured product. The polyisocyanate is preferably a liquid at ordinary temperature which does not require dilution with a solvent.

A cured product of hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, or the like, or an aliphatic polyisocyanate having no aromatic ring such as a burette, isocyanurate, or carbodiimide modified product thereof Is preferred for improving the weather resistance of the film.

In addition, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, liquid diphenylmethane diisocyanate,
Various polyisocyanates such as tolylene diisocyanate, tolidine diisocyanate, tetramethyl xylylene diisocyanate, naphthalene diisocyanate and the like, and burettes, isocyanurates and carbodiimide modified products thereof can be used. These polyisocyanates may be used in combination of two or more.

It is necessary that the mixing ratio of the polyisocyanate and the vinyl polymer having a hydroxyl group is 0.9 or less as an equivalent ratio of the isocyanate group in the polyisocyanate to the hydroxyl group in the vinyl polymer. Further, when the curable composition is one to which a low-molecular-weight polyhydric alcohol described below is added, the equivalent ratio of the isocyanate group to the total amount of the hydroxyl group in the vinyl polymer and the hydroxyl group in the low-molecular-weight polyhydric alcohol is used. It must be 0.9 or less. When the equivalent ratio is smaller than 0.5, the strength of the coating film obtained is low and the chemical resistance and the like become poor, so that the equivalent ratio is preferably 0.5 or more. On the other hand, if the equivalent ratio exceeds 0.9, the resulting coating film tends to foam under high humidity, which is not suitable.

The composition of the present invention is characterized in that a water-absorbing agent is used in combination, and the water-absorbing agent reacts with the polyisocyanate in the curable composition or in the air to generate carbon dioxide gas and foam. It is for suppressing. Therefore, by adding a water-absorbing agent, it is possible to maintain the cosmetic properties of the obtained coating surface, the strength of the coating, and the adhesiveness of the coating to the substrate. As the water absorbing agent, zeolite and powdered silica gel that physically adsorb water, calcium oxide, anhydrous gypsum, cement, and the like that chemically adsorb water can be used. The mixing ratio of the water absorbing agent is preferably 0.01 to 100 parts by weight of the vinyl polymer having a hydroxyl group.
-100 parts by weight, more preferably 1-30 parts by weight. When the proportion is less than 0.01 part by weight, the foaming suppressing effect is not sufficiently exhibited, and when the proportion is more than 100 parts by weight, the obtained cured film may be hard and brittle.

According to the present invention, it has been found that foaming is effectively suppressed by setting the equivalent ratio of isocyanate groups to hydroxyl groups in the composition to 0.9 or less and using a water absorbing agent.

Next, a low molecular weight polyhydric alcohol is added to the curable composition, if necessary, for the purpose of improving the mechanical properties of the cured film obtained. Specific examples of the low molecular weight polyhydric alcohol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol,
Examples include 1,6-hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, bisphenol A, trimethylolethane, trimethylolpropane, glycerin and sorbitol. These low molecular weight polyhydric alcohols can be used in combination of two or more.

When the low molecular weight polyhydric alcohol is blended, the preferred ratio is 0.1 to 50 parts by weight based on 100 parts by weight of the hydroxyl group-containing polymer, more preferably 1 to 3 parts by weight.
0 parts by weight. When this proportion is less than 0.1 part by weight, the effect of improving the mechanical properties of the obtained cured film is not sufficient, and when it is more than 50 parts by weight, the obtained cured film becomes hard and brittle. Sometimes.

In the case where the polyisocyanate does not have an aromatic ring, the curable composition of the present invention preferably contains a catalyst to accelerate the curability. Examples of the catalyst include 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 '' -Pentamethyldipropylene-triamine, tetramethylguanidine, triethylenediamine, N, N'-dimethylpiperazine, N, -methyl, N '-(2-dimethylamino) -ethylpiperazine, N-methylmorpholine, N (N'-dimethylaminoethyl) -morpholine, 1,2-
Dimethylimidazole, dimethylaminoethanol, dimethylaminoethoxyethanol, N, N, N'-trimethylaminoethyl-ethanol, N-methyl-N '-(2-hydroxyethyl) -ethanolamine, N-methyl-N'-(2 -Hydroxyethyl) -piperazine, N- (2-hydroxyethyl)
Amine catalysts such as morpholine, bis (2-dimethylaminoethyl) ether and ethylene glycol bis (3-dimethyl) -aminopropyl ether, lead octenoate, lead octylate, dibutyltin dilaurate, dibutyltin mercaptide, dibutyltin thiocarboxy And organic metal compounds such as dibutyltin dimalate, dioctyltin mercaptide and dioctyltin thiocarboxylate, and calcium carbonate and sodium bicarbonate. Among these, the use of an organometallic compound is preferable because of excellent reactivity of the urethanization reaction.

The amount of the catalyst to be added is 0.001 to 1 with respect to 100 parts by weight of the vinyl polymer having a hydroxyl group.
0 parts by weight is preferable, and 0.001 to 3 parts by weight is more preferable. When a catalyst is compounded in the composition, it is preferable to first mix the catalyst in a mixture excluding the polyisocyanate, and then mix the polyisocyanate, since a side reaction can be reduced.

The curable composition of the present invention may further contain, if necessary, barium sulfate, silicon oxide, talc,
Fillers such as mica, kaolin clay and calcium carbonate, natural mineral fibers such as sepiolite, attapulgite, and bolastonite, artificial fibers such as glass fiber, carbon fiber, aramid fiber, phenol fiber, and polyvinyl alcohol fiber, and organic thickeners Thickening and anti-sagging agents, coloring pigments such as phthalocyanine blue, phthalocyanine green, titanium oxide, carbon black and iron oxide, and hydrolysis prevention of carbodiimides, azodicarboxylates and fatty acid amides Agents, sterically hindered phenols, antioxidants such as aromatic diamines,
A benzotriazole-based, benzophenone-based, salicylic acid-based ultraviolet absorber, a silicone-based, acrylic-based, mineral-based defoamer, a leveling agent, and the like can be added.

When these components are blended, the blending ratio is preferably 100 parts by weight or less based on 100 parts by weight of the vinyl polymer having a hydroxyl group. When the curable composition of the present invention is applied to, injected or filled into a substrate, similarly to the conventional two-part curable urethane composition, a vinyl polymer having a hydroxyl group, a water absorbing agent and, if desired, a low molecular weight. What is necessary is just to mix the polyisocyanate immediately before use with the polyhydric alcohol previously mixed.

A mixture of a vinyl polymer having a hydroxyl group, a water-absorbing agent and, if necessary, a low-molecular-weight polyhydric alcohol is subjected to a dehydration operation after blending a catalyst and other blends if necessary and before blending a polyisocyanate. Is preferred. By performing the dehydration operation, it is possible to further effectively prevent the foaming of the composition caused by the reaction between the water and the polyisocyanate contained in the vinyl polymer having a hydroxyl group, the water absorbing agent and, if necessary, the low molecular weight polyhydric alcohol. be able to. As a method of the dehydration operation, a vacuum dehydration method and the like can be mentioned.

The method of applying the curable composition includes a method using a roller, a rake, a trowel, a spray and the like, and the method of injecting or filling is a method using a caulking gun, a spatula, a spatula, a trowel and the like. Is mentioned. The curable composition as described above, paint, waterproof material,
It can be suitably used for various uses such as coating materials such as wall materials and painted floor materials, and sealing materials.

As described above, according to the curable composition described in detail in the embodiment, the obtained curable film is excellent in weather resistance and has the following specific effects. -By using a vinyl polymer having a hydroxyl group, particularly one having a number average molecular weight of 500 to 20,000, the curable composition can be made to have a low viscosity, and workability in application, injection or filling of the curable composition. Can be improved.

The curable composition can have a low viscosity as described above and can be used as a solvent-free composition using no organic solvent, so that problems such as odor can be suppressed. -Since the curable composition can be a solventless composition,
The cured film of the curable composition can be made thicker.

[0046]

EXAMPLES Examples of the present invention, examples and comparative examples will be shown below, and the above embodiment will be described more specifically. In the following, parts and% are based on weight. (Production Example 1, Production of Polymer Having Hydroxyl Group by High-Temperature Continuous Polymerization Method) A 300-ml pressurized stirred tank reactor equipped with an electric heater was filled with diethylene glycol monoethyl ether, and the temperature was raised to 250 ° C. The pressure is adjusted to a gauge pressure of 2.45 to 2.65 MPa using a pressure controller.
(25-27 kgf / cm ² ).

Then, while keeping the pressure of the reactor constant, 16 parts of 2-hydroxyethyl methacrylate and 20 parts of 2-hydroxyethyl acrylate as the hydroxyl group-containing (meth) acrylate and 2-ethylhexyl acrylate as the ethylenically unsaturated monomer were used. A monomer mixture A-1 consisting of 54 parts of late and 10 parts of styrene was continuously supplied from the raw material tank to the reactor at a constant supply rate (23 g / min, residence time: 12 minutes). A reactant corresponding to the supply amount of the monomer mixture A-1 was continuously extracted from the outlet. Immediately after the start of the reaction, after the reaction temperature once decreased, a temperature increase due to the heat of polymerization was observed. However, the reaction temperature was maintained at 270 to 271 ° C. by controlling the heater.

The point at which the temperature was stabilized after the start of the supply of the monomer mixture A-1 was defined as the starting point of the withdrawal of the reaction solution, and the reaction was continued for 50 minutes. As a result, 1150 parts of the monomer mixture A-1 was obtained. Then, 1130 parts of the reaction solution was recovered.

Next, the reaction solution was introduced into a thin film evaporator,
Volatile components such as unreacted monomers were separated to obtain 990 g of a concentrated solution (copolymer B-1). From the gas chromatograph,
There was no unreacted monomer in the concentrate. The number average molecular weight (hereinafter, abbreviated as Mn) of the copolymer B-1 in which the molecular weight determined by GPC is 2,000, and the weight average molecular weight (hereinafter, abbreviated as Mw) is obtained by using tetrahydrofuran as a solvent and converting the molecular weight obtained by GPC into polystyrene. Is 3,600, Mw / M
n was 1.80. The concentrated solution has a hydroxyl value of 17
It was 3 mgKOH / g. (Production Example 2, Production of a polymer having a hydroxyl group by a solution polymerization method) 10 parts of hydroxyethyl methacrylate and 20 parts of hydroxyethyl acrylate as a hydroxyl group-containing (meth) acrylate, 2- as an ethylenically unsaturated monomer
A mixture obtained by mixing 70 parts of ethylhexyl acrylate was used as a monomer mixture A-2.

In a four-necked flask equipped with a reflux condenser, a thermometer, a dropping funnel, a glass tube for purging nitrogen and a stirrer, 15 parts of the monomer mixture A-2 and methyl isobutyl ketone (hereinafter referred to as MIBK). And 100 parts of 2,2′-azoisobutyronitrile were charged, and the polymerization reaction was started at 90 ° C. while blowing nitrogen. Thereafter, 85 parts of the monomer mixture A-2, 25 parts of MIBK and 2,2′-
A polymerization reaction was carried out by continuously dropping 31 parts of a solution composed of 6 parts of azobisisobutyronitrile over 6 hours.

The solvent was distilled off from the obtained reaction solution under reduced pressure to obtain a copolymer B-2. The molecular weight of copolymer B-2 determined by the same method as in Production Example 1 was Mn of 8,800 and Mw of 1
It was 9,000 and Mw / Mn was 2.2. The hydroxyl value was 146 mgKOH / g. (Example 1) 100 parts of B-1 obtained in Production Example 1, 0.01 part of di-n-butyltin dilaurate, 3 parts of propylene glycol, 5 parts of molecular sieve 5A, polysiloxane-based defoamer BYK -066 [made by Tetsutani Corporation] 1 copy,
7 parts of titanium oxide, 40 parts of kaolin clay and sepiolite (trade name Miracle LFC-5, manufactured by Omi Mining Co., Ltd.)
Five parts were added to a planetary mixer, and the mixture was stirred at room temperature for 15 minutes. Subsequently, while kneading at 70 ° C., a dehydration operation was performed in vacuum for 1 hour to obtain a mixture C-1.

Next, 100 parts of C-1 (2.34 meq
/ G) and an isocyanurate of hexamethylene diisocyanate [Sumidur N
3500, NCO group content 5.14 meq / g, manufactured by Sumitomo Bayer Urethane Co., Ltd.] with an NCO / OH equivalent ratio of 0.6
And stirred thoroughly to produce a composition.

The obtained composition was evaluated according to the following evaluation method. Table 1 shows the results. (Tensile physical properties) The obtained composition was immediately poured onto a fluororesin plate, and allowed to stand at 20 ° C and a humidity of 60% to be cured. 1
The average film thickness of the cured film after 68 hours was 1.0 to 1.1.
mm.

The obtained cured film was measured at a tensile speed of 200 mm / min according to JIS K 6301, and the tensile strength and elongation were measured. (Foamability) The composition was poured onto a mortar plate so that the dry film thickness was about 2 mm.
The reaction was cured for 168 hours at 85 ° C. and a humidity of 85%. The obtained cured film was visually observed.

In Tables 1 and 2, △, Δ, and X have the following meanings. ：: No abnormality in appearance. わ ず か: Slight foaming in appearance. ×: Large foaming in appearance. (Surface tack) The composition was placed on a mortar plate so that the dry film thickness was about 2 mm. 1 at 20 ° C, 60% humidity
The reaction was cured for 68 hours. The obtained cured film was observed by finger touch.

In Tables 1 and 2, △, Δ, and X have the following meanings. ：: no tack △: slight touch at fingertip
×: Feel a strong tack at the fingertip (Example 2) 100 parts (2.34 meq / g) of C-1 obtained in Example 1 and the isocyanurate of hexamethylene diisocyanate used in Example 1 were NCO /
The mixture was added at an OH equivalent ratio of 0.8 and stirred sufficiently to produce a composition.

The obtained composition was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results. Example 3 100 parts of B-1 obtained in Production Example 1, 0.01 part of di-n-butyltin dilaurate, 3 parts of propylene glycol, 30 parts of molecular sieve 5A, polysiloxane-based defoamer BYK -066 1 part, titanium oxide 7 parts, kaolin clay 40 parts and sepiolite 5 parts were added to a planetary mixer and stirred at room temperature for 15 minutes. Subsequently, while kneading at 70 ° C., a dehydration operation was performed for 1 hour under vacuum to obtain a mixture C-2.

Next, 100 parts of this mixture C-2 (2.
02meq / g) and the isocyanurate of hexamethylene diisocyanate used in Example 1 at an NCO / OH equivalent ratio of 0.6, followed by sufficient stirring to produce a composition.

The obtained composition was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results. Example 4 100 parts of B-1 obtained in Production Example 1, 0.01 part of di-n-butyltin dilaurate, 3 parts of propylene glycol, 5 parts of quicklime, polysiloxane-based defoamer BY
1 part of K-066, 7 parts of titanium oxide, kaolin clay 40
And 5 parts of sepiolite were added to a planetary mixer, stirred at room temperature for 15 minutes, and subsequently kneaded at 70 ° C., while performing a dehydration operation for 1 hour under vacuum to obtain a mixture C-3.

Next, 100 parts of this mixture C-3 (2.
34 meq / g) and the isocyanurate of hexamethylene diisocyanate used in Example 1 were added at an NCO / OH equivalent ratio of 0.7, and the mixture was sufficiently stirred to produce a composition.

The obtained composition was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results. (Example 5) 100 parts of B-2 obtained in Production Example 2, 0.01 part of di-n-butyltin dilaurate, 3 parts of propylene glycol, 5 parts of molecular sieve 5A, polysiloxane-based defoamer BYK -066, 7 parts of titanium oxide, 40 parts of kaolin clay and 5 parts of sepiolite were added to a planetary mixer and stirred at room temperature for 15 minutes. Subsequently, while kneading at 70 ° C., a dehydration operation was performed for 1 hour under vacuum to obtain a mixture C-4.

Next, 100 parts of this mixture C-4 (2.
04 meq / g) and the isocyanurate of hexamethylene diisocyanate used in Example 1 at an NCO / OH equivalent ratio of 0.6, and sufficiently stirred to produce a composition.

The obtained composition was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results. Example 6 100 parts of B-1 obtained in Production Example 1, 0.01 part of di-n-butyltin dilaurate, 5 parts of molecular sieve 5A, and a polysiloxane-based defoamer BYK-066
1 part, 7 parts of titanium oxide, 40 parts of kaolin clay and 5 parts of sepiolite were added to a planetary mixer, and the mixture was stirred at room temperature for 15 minutes. A mixture C-5 was obtained.

Next, 100 parts of this mixture C-5 (2.
34 meq / g) and the isocyanurate of hexamethylene diisocyanate used in Example 1 were added at an NCO / OH equivalent ratio of 0.6, and sufficiently stirred to produce a composition.

The obtained composition was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results. (Example 7) 100 parts of B-1 obtained in Production Example 1, 0.01 part of di-n-butyltin dilaurate, 3 parts of propylene glycol, 5 parts of molecular sieve 5A, polysiloxane-based defoamer BYK -066, 7 parts of titanium oxide, 40 parts of kaolin clay, and 5 parts of sepiolite were added to a planetary mixer, stirred at room temperature for 15 minutes, and subsequently kneaded at 70 ° C, followed by dehydration in vacuum. Performed for 1 hour to obtain a mixture C-6.

Then, 100 parts of this mixture C-6 (2.
34 meq / g) and the isocyanurate of hexamethylene diisocyanate used in Example 1 were added at an NCO / OH equivalent ratio of 0.4, and the mixture was sufficiently stirred to produce a composition.

The obtained composition was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results.

[0068]

[Table 1] As shown in Table 1, in Examples 1 to 6, the mechanical properties indicated by the tensile strength and the elongation were good, there was no problem in the foaming property, and no tack on the coating surface was observed. In addition, in Example 7, the elongation was excellent, and there was no problem in the foamability. (Comparative Example 1) 100 parts of B-1 obtained in Production Example 1, 0.01 part of di-n-butyltin dilaurate, 3 parts of propylene glycol, and 1 of polysiloxane-based defoamer BYK-066
Parts, 7 parts of titanium oxide, 40 parts of kaolin clay and 5 parts of sepiolite were added to a planetary mixer, and 1 part was added at room temperature.
After stirring for 5 minutes and subsequently kneading at 70 ° C., a dehydration operation was performed in vacuum for 1 hour to obtain a mixture C-7 which is a vinyl polymer having a hydroxyl group.

Next, 100 parts of this mixture C-7 (2.
41 meq / g) and the isocyanurate of hexamethylene diisocyanate used in Example 1 were added at an NCO / OH equivalent ratio of 0.4, followed by sufficient stirring to produce a composition.

The obtained composition was evaluated in the same manner as in Example 1. Table 2 shows the evaluation results. (Comparative Example 2) 100 parts of B-1 obtained in Production Example 1, 0.01 part of di-n-butyltin dilaurate, 3 parts of propylene glycol, 1 part of polysiloxane-based defoamer BYK-066
Parts, 7 parts of titanium oxide, 40 parts of kaolin clay and 5 parts of sepiolite were added to a planetary mixer, and 1 part was added at room temperature.
After stirring for 5 minutes and subsequently kneading at 70 ° C., a dehydration operation was performed in vacuum for 1 hour to obtain a mixture C-8 which is a vinyl polymer having a hydroxyl group.

Next, 100 parts of this mixture C-8 (2.
41 meq / g) and the isocyanurate of hexamethylene diisocyanate used in Example 1 were added at an NCO / OH equivalent ratio of 1.1, followed by sufficient stirring to produce a composition.

The obtained composition was evaluated in the same manner as in Example 1. Table 2 shows the evaluation results. (Comparative Example 3) 100 parts of B-1 obtained in Production Example 1, 0.001 part of di-n-butyltin dilaurate, 3 parts of propylene glycol, 5 parts of molecular sieve 5A, polysiloxane-based defoamer BYK -066 parts, titanium oxide 7 parts,
40 parts of kaolin clay and 5 parts of sepiolite are added to a planetary mixer, stirred at room temperature for 15 minutes, and subsequently kneaded at 70 ° C., while performing a dehydration operation for 1 hour under vacuum to obtain a hydroxyl-containing vinyl polymer. A mixture C-9 was obtained.

Next, 100 parts of this mixture C-9 (2.
34 meq / g) and the isocyanurate of hexamethylene diisocyanate used in Example 1 were added at an NCO / OH equivalent ratio of 1.1, and the mixture was sufficiently stirred to produce a composition.

The obtained composition was evaluated in the same manner as in Example 1. Table 2 shows the evaluation results.

[0075]

[Table 2] As shown in Table 2, when no water-absorbing agent was contained (Comparative Example 1), when no water-absorbing agent was contained and the equivalent ratio of isocyanate groups to hydroxyl groups exceeded 0.9 (Comparative Example 2), and when isocyanate to hydroxyl groups was used. When the equivalent ratio of the group exceeded 0.9 (Comparative Example 3), one of the tensile strength, the elongation, the foaming property, and the tack on the surface of the coating film was poor.

The technical ideas grasped from the above embodiment will be described below. The hydroxyl group-containing vinyl polymer has a hydroxyl value of 10 to 400 mgKOH / g and a glass transition temperature of -70 to 3
The curable composition according to claim 1, wherein the curable composition is a copolymer having 0 ° C and a number average molecular weight of 500 to 20,000, and the polyisocyanate has an average of two or more isocyanate groups.

With such a constitution, the cosmetic properties of the obtained coating surface, the strength of the coating, and the adhesion of the coating to the substrate can be maintained in a well-balanced manner, and the weather resistance of the coating can be improved.

The curable composition according to claim 1, wherein the content of the water absorbing agent is 0.1 to 100 parts by weight based on 100 parts by weight of the vinyl polymer having a hydroxyl group. With such a configuration, the foaming suppressing effect can be sufficiently exhibited, and the obtained cured film can be prevented from becoming hard.

The hydroxyl-containing vinyl polymer 10
0.1 to 0.1 parts by weight of low molecular weight polyhydric alcohol
50 parts by weight, and the equivalent ratio of the isocyanate group contained in the polyisocyanate to the total of the hydroxyl groups contained in the vinyl polymer and the low molecular weight polyhydric alcohol is 0.5 to 0.1.
The curable composition according to claim 1, wherein the content of the water-absorbing agent is 0.1 to 100 parts by weight based on 100 parts by weight of the vinyl polymer having a hydroxyl group.

In the case of such a constitution, particularly, the mechanical properties of the obtained cured film can be improved. -The vinyl polymer having a hydroxyl group is 150 to 35;
The curable composition according to claim 1, which is obtained by continuous polymerization at a polymerization temperature of 0 ° C.

With such a constitution, a hydroxyl group-containing copolymer having a low molecular weight, a low viscosity, a high purity, and a uniform molecular weight distribution can be obtained, and the weather resistance of the obtained film can be improved. it can.

[0082]

As described in detail above, according to the present invention,
The following effects are obtained. ADVANTAGE OF THE INVENTION According to the curable composition of this invention, the cosmetics of the obtained coating surface, the intensity | strength of a coating, the adhesiveness of the coating to a base material can be maintained, and the weather resistance of a coating is excellent. Therefore, the curable composition is useful in various industrial fields such as paints, waterproofing materials, flooring materials, sealing materials, injection materials and adhesives.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Koichi Fukushima 1-1-1, Funami-cho, Minato-ku, Nagoya-shi, Aichi F-term in Nagoya Research Institute, Inc. (reference) 4J002 CK051 DE086 DG056 DJ006 FD206 4J034 BA03 DB05 DB07 DC50 DP18 FA02 FB01 FC05 FD01 HA07 HC01 HC03 HC12 HC13 HC17 HC22 HC35 HC46 HC52 HC64 HC67 QA03 RA07 RA08 4J038 CG142 CH031 CH032 CH041 CH042 CH121 CH122 CH131 CH132 CJ031 CJ032 DB371 DB372 DG141 DG191 DG192 GA271 DG 271 271 MA13 MA14 NA01 NA03 NA11 PC02 PC04 PC08

Claims (1)

[Claims] 1. A curable composition comprising a vinyl polymer having a hydroxyl group, a polyisocyanate and a water absorbing agent, wherein the equivalent ratio of the isocyanate group to the hydroxyl group is 0.9 or less.