JP2002155126A - Two-pack curable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new two-pack curable composition which is excellent in weatherability and mechanical strength, has sufficient extensibility, and gives little surface residual tack. SOLUTION: The two-pack curable composition consists of a principal component containing an isocyanato-containing polyurethane prepolymer obtained by reacting a polyisocyanate compound with a polyoxyalkylene polyol having a hydroxyl value OHV of 5-60 mgKOH/g and an overall degree of unsaturation USV (meq/g) satisfying the relation of the formula: USV<=1.2/OHV; and a curing agent containing an acrylic polymer having an active hydrogen group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an isocyanate group-containing polyurethane prepolymer obtained by reacting a polyoxyalkylene polyol having a low total unsaturation with a polyisocyanate compound, and an active hydrogen group-containing acrylic polymer. , Less residual tack on the surface of cured product,
The present invention also relates to a two-part curable composition having excellent weather resistance and extensibility, and the composition of the present invention comprises a sealing material, a wall material,
It is useful as a waterproof material, floor material, paint, and the like.

[0002]

2. Description of the Related Art Polyurethane resins are widely used as sealing materials, wall materials, waterproof materials, flooring materials, paints, etc. because of their excellent properties such as rubber elasticity, abrasion resistance, cold resistance and durability. ing. These generally comprise a polyurethane prepolymer having an isocyanate group at a molecular end obtained by reacting a polyoxyalkylene polyol and a polyisocyanate compound as a main component, a polyoxyalkylene polyol or a polyamine as a curing agent, and other necessary components. A composition containing a filler, a plasticizer, a stabilizer and the like is used. However, such a composition has insufficient weather resistance, and deteriorates when used for a long time outdoors or the like.
There is a disadvantage that chalking and cracks occur. As a method for improving the weather resistance, an acrylic urethane composition containing a hydroxyl group-containing acrylic polymer (acrylic polyol) has been proposed (Japanese Patent Publication No. 22-22).
781, JP-A-5-262808, JP-A-7- 1970
11).

[0003] However, while these compositions are excellent in weather resistance, they have the drawback that the elongation rate of the cured product is insufficient, and that the surface after curing has a tackiness and is easily contaminated by dust and the like. Further, as an acrylic urethane composition having no tackiness on the surface after curing, a composition using an acrylic polymer having at least one hydroxyl group at each terminal (JP-A-7-10957) has been proposed, but is satisfactory. I couldn't do it.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a two-pack type acrylic urethane composition which improves the above-mentioned drawbacks, has excellent weather resistance and extensibility, and has little residual tack on the surface. is there.

[0005]

That is, the present invention relates to a polyisocyanate compound and a hydroxyl value OHV (mg KOH / g).
Isocyanate group-containing polyurethane obtained by a reaction with a polyoxyalkylene polyol satisfying the following general formula (1): 5 to 60 and a total degree of unsaturation USV (meq / g): USV ≦ 1.2 / OHV (1) The present invention relates to a two-part curable composition comprising a main agent containing a prepolymer and a curing agent containing an active hydrogen group-containing acrylic polymer.

In a preferred embodiment, the acrylic polymer having an active hydrogen group has a number average molecular weight of 1,000 to 5,
000 and a hydroxyl value of 10 to 400 mg KOH /
g. The two-part curable composition according to the above, which is g.

In a further preferred embodiment, the two-part curable type according to any of the above, wherein the ratio of the polyoxyalkylene polyol to the active hydrogen group-containing acrylic polymer in the composition is from 10/90 to 90/10. Composition.

[0008]

DETAILED DESCRIPTION OF THE INVENTION The isocyanate group-containing polyurethane prepolymer used in the present invention comprises a polyisocyanate compound and a hydroxyl value OHV (mg KOH / g).
And a polyoxyalkylene polyol satisfying the following general formula (1): USV ≦ 1.2 / OHV (1) having a free isocyanate group by a known method. It was reacted so as to remain. As a production method, for example, a polyisocyanate compound is reacted with the above-described polyoxyalkylene polyol at 100 ° C. for several hours to produce the compound.
The isocyanate group content is preferably from 0.3 to 7.0% by weight, and a particularly preferred range is from 0.5 to 5.0% by weight. When the isocyanate group content is less than 0.3% by weight, the viscosity of the polyurethane prepolymer is too high, so that the workability tends to be deteriorated when mixing the main agent and the curing agent or applying the mixture. If it exceeds, the elongation rate of the cured product tends to decrease.

Examples of the polyisocyanate compound used in the present invention include: 1) tolylene diisocyanate (including various mixtures of isomers), diphenylmethane diisocyanate (including various mixtures of isomers), 3. 3'-dimethyl-4 / 4'-
Biphenylene diisocyanate, 1,4-phenylene diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, naphthylene diisocyanate, dicyclohexyl methane 4.4'-diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, hydrogenated xylene diisocyanate, 1.4 -Cyclohexyl diisocyanate, 1
-Methyl-2,4-diisocyanato-cyclohexane,
Diisocyanates such as 2,4,4-trimethyl-1,6-diisocyanato-hexane and norbornane diisocyanate; 2) 4,4 ', 4 "-triphenylmethane triisocyanate; tris (4-phenylisocyanato)
3) triisocyanates such as thiophosphate; 3) urethanized modified isocyanates, isocyanurated modified products, carbodiimidized modified products, buret modified products, crude tolylene diisocyanate, polymethylene polyphenylisocyanate, etc. It is a functional isocyanate. The hydroxyl value OHV (m
gKOH / g) is 5 to 60 and the total degree of unsaturation is US
A polyoxyalkylene polyol whose V (meq / g) satisfies the general formula (1): USV ≦ 1.2 / OHV (1) refers to, for example, Zn3 as described in JP-B-44-551. Metal cyanide complexes such as [Co (CN) 6] 2,
An alkylene oxide compound is converted to an active hydrogen compound using cesium hydroxide as described in JP-A-7-278289 or a phosphazenium compound as described in JP-A-11-106500 as a catalyst. Obtained by adding. Here, the active hydrogen compound is, for example, water, methanol, ethanol, normal-propanol, isopropanol, normal-butyl alcohol, sec-butyl alcohol, and tert.
-Butyl alcohol, isopentyl alcohol, ter
alcohols having 1 to 10 carbon atoms such as t-pentyl alcohol and normal-octyl alcohol; for example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-
Polyhydric alcohols having 2 to 10 carbon atoms and having 2 to 4 hydroxyl groups, such as butanediol, trimethylolpropane, glycerin, and pentaerythritol, such as polyethylene oxide, polypropylene oxide, and copolymers thereof. Or 6
Polyalkylene oxides having a molecular weight of 100 to 10,000 and having 2 to 6 hydroxyl groups at the terminals, such as N, N'-dimethylethylenediamine, N, N'-diethylethylenediamine or di ( Polyhydric amines having 2 to 3 carbon atoms and having 2 to 3 secondary amino groups such as 2-methylaminoethyl) amine, such as piperazine, pyrazine,
4 to 20 carbon atoms such as 4,7-triazacyclononane
Cyclic polyamines containing two or three secondary amino groups.

[0010] Of these active hydrogen compounds, water is more preferable, and examples thereof include water such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, trimethylolpropane, glycerin, and pentaerythritol. Polyhydric alcohols having 2 to 4 hydroxyl groups having 2 to 10 carbon atoms, such as polyethylene oxide, polypropylene oxide or copolymers thereof, having 2 to 6 terminals and having 2 to 6 terminals Having a molecular weight of 100 to 10,000 having one hydroxyl group
00 polyalkylene oxides.

Examples of the alkylene oxide compound include ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, styrene oxide, cyclohexene oxide, epichlorohydrin, epibromohydrin, methyl glycidyl ether,
Epoxy compounds such as allyl glycidyl ether and phenyl glycidyl ether. These may be used in combination of two or more. When used in combination, a method of simultaneously using a plurality of alkylene oxide compounds, a method of sequentially using a plurality of alkylene oxide compounds, or a method of repeatedly repeating the steps can be employed. Among these alkylene oxide compounds, ethylene oxide, propylene oxide, 1,2-butylene oxide or styrene oxide is preferred, and ethylene oxide and propylene oxide are more preferred.

The use of a commonly used catalyst such as KOH is not preferable because the total degree of unsaturation increases. Here, the total degree of unsaturation in the polyoxyalkylene polyol is an index of the amount of a monool having an unsaturated group at a molecular terminal generated mainly by a side reaction of propylene oxide when synthesizing the polyoxyalkylene polyol. Things. Since the monol has a low molecular weight as compared with the polyoxyalkylene polyol produced by the main reaction, the molecular weight distribution of the polyoxyalkylene polyol is significantly widened and the average number of functional groups is reduced.
Therefore, when a polyoxyalkylene polyol having a high monol content is used, the physical properties such as hardness and mechanical strength are lowered, which causes deterioration of various physical properties. Therefore, the monol should be as small as possible and the total unsaturation U
SV (meq / g) ≦ 1.2 / OHV (mgKOH /
g) must be satisfied. 1.2 / O total unsaturation
When the HV exceeds HV, problems such as a decrease in mechanical strength of the cured composition and a decrease in contamination due to residual tack on the surface occur.

The total degree of unsaturation USV (meq / g)
Can be measured by the method described in JIS K1557.

The hydroxyl value (mgKOH / g) of the polyoxyalkylene polyol must be in the range of 5-60. When the hydroxyl value (mgKOH / g) is less than 5,
Since the viscosity of the polyoxyalkylene polyol becomes too high, the workability of the composition decreases. If it exceeds 60, the hardness of the composition after curing becomes too high, and the elongation decreases.

The hydroxyl value (mgKOH / g) is expressed in J
It can be measured according to IS K 1557.

The active hydrogen group-containing acrylic polymer used in the present invention can be obtained by a known method. For example, 1) a plurality of monomers which are obtained by polymerizing a monomer having a hydroxyl group and an unsaturated monomer containing a (meth) acrylate ester using a polymerization initiator and a chain transfer agent, and bonding pendantly to a molecular chain. 2) a method for obtaining a polymer having two hydroxyl groups, 2) using an unsaturated monomer mixture containing an unsaturated monomer having a hydroxyl group and an (meth) acrylate ester with an initiator having a hydroxyl group or a chain transfer agent. A method of obtaining a hydroxyl-containing acrylic polymer having at least one hydroxyl group at a molecular chain terminal and at least one hydroxyl group at an arbitrary position in the molecular chain by polymerization, 3) General formula 2: HO-A- (S) n- B-OH (2) (wherein, A and B each represent a divalent organic group, n
Is an integer of 2 to 5. ), The polymerization of the unsaturated monomer (b) in the presence of the compound (a) using the radical polymerization initiator (c) is carried out. Method for obtaining a polymer having one hydroxyl group at each end of a molecule obtained by presenting at least 50 mole times the polymerization initiator (c) (JP-A-7-10957), 4) (meth) acrylic acid An unsaturated monomer containing an ester is polymerized with an organic peroxide initiator using an organic sulfonic acid compound in the presence of an alcohol compound to form a polymer having at least two hydroxyl groups at both ends of the molecule. Obtaining method (JP-A-7-10957),
5) A method of continuously polymerizing a hydroxyl group-containing (meth) acrylate and an ethylenically unsaturated monomer at a high temperature of 150 to 350 ° C. to obtain a hydroxyl group-containing acrylic polymer (Japanese Patent Laid-Open No. 10-1)
95111, JP-A-10-17640).

The term "(meth) acrylic acid" means containing one or both of acrylic acid and methacrylic acid.

Among them, the polymer obtained by the methods 3) and 4) is a telechelic polymer having hydroxyl groups at both ends of the molecule, and a composition using the polymer has an improved elongation rate and a residual tackiness on the surface. It is preferable because it has an effect on reduction. The method 5) can reduce the production cost, and the obtained polymer is
It is preferable because of its low viscosity.

The active hydrogen group-containing acrylic polymer preferably has a number average molecular weight of 1,000 to 50,000 and a hydroxyl value of 10 to 400 mgKOH / g. When the hydroxyl value is less than 10 mgKOH / g, the crosslink density after curing becomes insufficient, and not only the surface tack remains, but also there is a tendency that sufficient mechanical strength cannot be obtained. If it exceeds 400 mgKOH / g, the crosslink density tends to be too high and sufficient elongation cannot be obtained.

The hydroxyl value (mgKOH / g) is expressed in J
It can be measured according to IS K 1557.

When the number average molecular weight is less than 1,000,
Since the molecular weight is too small and the distance between crosslinking points after curing is too short, there is a tendency that sufficient elongation cannot be obtained.
If it exceeds 000, the polymer viscosity becomes too high,
There is a tendency that problems such as difficulty in mixing and working the two liquids and ensuring sufficient workability cannot be ensured.

The number average molecular weight can be measured by a standard polystyrene conversion method using gel osmotic pressure chromatography (GPC).

Examples of the acrylate include alkyl acrylates, specifically, methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, isobutyl acrylate, and trimethylolpropane triacrylate.
One or more of these are used.

Examples of the methacrylate include alkyl methacrylates, specifically, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, trimethylolpropane trimethacrylate, methoxydiethylene methacrylate, methoxydiethylene methacrylate, and methoxy methacrylate. Examples include polyethylene glycol methacrylate and allyl methacrylate, and one or more of these are used.

As the (meth) acrylic acid ester, an ester of a higher alcohol can be used together with the alkyl ester having a relatively short carbon number as described above. As the higher alcohol, an alcohol having 8 or more carbon atoms is preferable. is there. Specifically, monomers such as n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, myristyl (meth) acrylate, cetyl (meth) acrylate, and stearyl (meth) acrylate For example, one or more of these are used.

Specific examples of the monomer having a hydroxyl group include (meth) acrylic acid derivatives such as hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate, vinyl ether derivatives such as hydroxyethyl vinyl ether, allyl alcohol, and the like. Examples include methylolated acrylamide, methylolated methacrylamide, and the like,
Examples of the monomer having an amino group include methacrylic acid-2,
Compounds known to those skilled in the art such as 2,6,6-tetramethylpiperidine are exemplified. One or more of these monomers are selected and used.

In the present invention, as the monomer used as required together with the above (meth) acrylic monomer, a so-called vinyl polymerizable monomer can be used, and a styrene monomer (styrene, α -Methylstyrene, vinyltoluene, etc.), monomers having a nitrile group such as acrylonitrile, methacrylonitrile, vinyl halides such as vinyl chloride, vinylidene halides such as vinylidene chloride, vinyl alcohol derivatives such as vinyl acetate, vinyl ethers, Compounds known to those skilled in the art, such as vinylpyrrolidone and acrylamide, can be exemplified. In addition, two or more monomers can be freely selected and used in combination according to the required properties.

An unsaturated monomer containing a (meth) acrylic acid ester is polymerized with an organic peroxide-based initiator using an organic sulfonic acid compound in the presence of an alcohol compound, so that at least two terminals are present at both ends of the molecule. Examples of the alcohol compound used in the method for obtaining a polymer having one hydroxyl group include aliphatic or alicyclic alcohols such as methyl alcohol, ethyl alcohol, butyl alcohol, neopentyl alcohol, and cyclohexanol, ethylene glycol, and propylene. Aliphatic or alicyclic glycols such as glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-dimethylolcyclohexane, 1,4-dihydroxycyclohexane, glycerin, trimethylolpropane , Pentaerythritol, Risuritoru, threose, ribose, a multi-functional alcohol and sugars such as sucrose,
Glycol ethers such as diethylene glycol, dipropylene glycol, and triethylene glycol; amino alcohols such as monoethanolamine, diethanolamine, triethanolamine, and N-methyldiethanolamine; fragrances such as benzyl alcohol, hydroquinone diethylol ether, and bishydroxyethyl terephthalate Examples include alcohol compounds having a ring, methoxyethanol, ethoxyethanol, ethylene glycol monoacetate, diethylene glycol monoacetate, sorbitan fatty acid esters, and other mono- or polyacylated derivatives or mono- or polyetherified derivatives of the above-mentioned alcohol compounds. Each of the above alcohol compounds has at least one hydroxyl group and a methylene proton or a methine proton, and this proton dissociates to generate a radical, thereby generating an acrylic polymer. As a result, the hydroxyl group of the alcohol compound used as a raw material forms the terminal group of the polymer as it is. All compounds known to those skilled in the art other than those exemplified here can be used. The active hydrogen group-containing acrylic polymer obtained by using a monofunctional alcohol as the alcohol compound becomes substantially bifunctional,
When a diol is used as the alcohol compound, the active hydrogen group-containing acrylic polymer becomes substantially tetrafunctional.

The organic sulfonic acid compound has a function as a catalyst for extracting the above-mentioned methylene proton or methine proton of the alcohol compound, and is not limited as long as it has such a function. Specifically, methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, aliphatic sulfonic acids such as octanesulfonic acid, alicyclic sulfonic acids such as cyclohexanesulfonic acid,
Aromatic monosulfonic acids such as benzenesulfonic acid, benzenedisulfonic acid, toluenesulfonic acid, naphthalenesulfonic acid, naphthalenedisulfonic acid, 1-naphthol-4-sulfonic acid, 2-naphthylamine-6-sulfonic acid and dodecylbenzenesulfonic acid; Examples thereof include sulfonic acids having a polymerizable unsaturated group, such as disulfonic acids, (meth) acrylic acid-2-sulfonic acid, styrene sulfonic acid, and vinyl sulfonic acid, and may be used alone or in combination of two or more. In addition, an inorganic acid such as hydrochloric acid or sulfuric acid or phosphoric acid may be used together with these organic sulfonic acid compounds. The organic peroxide-containing initiator used for the polymerization is a substance containing an organic peroxide or an organic peroxide and a decomposition accelerator for accelerating the decomposition of the organic peroxide. Well-known compounds such as oxide, dicumyl peroxide, MEK peroxide, and cyclohexanone peroxide are used. As the decomposition accelerator, inorganic acids such as hydrochloric acid and sulfuric acid, organic acids such as acetic acid and benzoic acid, ferrocene, and naphthenic acid are used. Metal salts, sulfites,
Compounds such as various mercaptans, amines, and reducing compounds such as ascorbic acid are exemplified.

General formula (2): HO-A- (S) n-B-OH (2) (where A and B each represent a divalent organic group,
Is an integer of 2 to 5. ), The polymerization of the unsaturated monomer (b) in the presence of the compound (a) using the radical polymerization initiator (c) is carried out. Specific examples of the compound represented by the general formula (2) used in the hydroxyl group-containing acrylic polymer obtained by being present at 50 times or more the amount of the polymerization initiator (c) include bis (2- Examples thereof include (hydroxyethyl) disulfide, bis (2-hydroxyethyl) trisulfide, bis (2-hydroxypropyl) disulfide, and bis (2-hydroxypropyl) trisulfide. When the ratio of (a) / (c) is 50 or less, the number of hydroxyl groups at both ends is decreased, and as a result, a polymer having low telechelic properties is not preferred.

Examples of the radical polymerization initiator include azobisisobutyronitrile, 2,2'-azobis [2-methyl-N-
(2-hydroxyethyl) propionamide], and a redox catalyst can also be used.

A hydroxyl group-containing acrylic polymer having at least one active hydrogen at the molecular chain terminal and at least one at an arbitrary position in the molecular chain can be prepared, for example, in the presence of 2-mercaptoethanol and / or thioglycolic acid. It can be obtained by polymerizing an acrylic monomer and, if necessary, another monomer in the presence of a radical polymerization initiator. In a preferred embodiment, a polyol compound such as polyoxypropylene glycol is used in the polymerization.

An active hydrogen group obtained by polymerizing a monomer having active hydrogen and an unsaturated monomer containing (meth) acrylate using a polymerization initiator or a polymerization initiator and a chain transfer agent. The containing acrylic polymer is obtained by copolymerizing the above-mentioned hydroxyl group-containing monomer as an essential component.

The same polymerization initiator as described above can be used. As the chain transfer agent, compounds well known to those skilled in the art can be used, and alkyl mercaptans such as lauryl mercaptan and dodecyl mercaptan are exemplified as particularly preferable compounds. As the polymerization mode, any polymerization mode such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, and solid phase polymerization may be used. Further, the polymerization may be carried out by charging the raw material monomer and the radical polymerization initiator all at once, or may be carried out while supplying each component to the polymerization system as needed. In addition, first, at least a part of the solvent may be charged in the polymerization vessel in advance, and the polymerization may be performed by supplying the raw material monomer and the radical polymerization initiator thereto. Further, the polymerization vessel used in the present invention may be a batch type such as a flask type or a kneader, a tube type of a piston flow,
Depending on the viscosity of the polymer, a continuous type such as a twin screw extruder may be used. Also, a semi-batch type reactor can be used without any problem. The polymerization temperature when producing the (meth) acrylate copolymer is not particularly limited, and there is no problem as long as it is within a temperature range in which ordinary radical polymerization is performed.

When producing the (meth) acrylic ester copolymer, the reaction can be carried out under normal pressure, but it can also be carried out under pressure in an autoclave or extruder.

According to the high-temperature continuous polymerization method for obtaining a copolymer by continuous polymerization at a high temperature, a hydroxyl group-containing copolymer having a low molecular weight and a low viscosity can be obtained.
There is no need to use a thermal polymerization initiator, or even when a thermal polymerization initiator is used, a small amount of a copolymer having the desired molecular weight can be obtained, so that impurities that generate radical species by heat or light are almost eliminated. Since a copolymer having a high purity without containing is obtained, the cured composition can have excellent weather resistance. Further, a copolymer having a lower polydispersity than that obtained by conventional solution polymerization can be obtained.
As a high-temperature continuous polymerization method, JP-A-57-502171, 59-6
No. 207, No. 60-215007 and the like. For example, filling a pressurizable reactor with a solvent,
After setting to a predetermined temperature under pressure, a monomer mixture comprising a hydroxyl group-containing (meth) acrylate, an ethylenically unsaturated monomer and, if necessary, a polymerization solvent is supplied to the reactor at a constant supply rate. And a method of extracting a reaction solution in an amount corresponding to the supply amount of the monomer mixture. When a polymerization solvent is used, the solvent charged into the reactor at the start of the reaction and the polymerization solvent mixed with the monomer mixture may be the same or different. As the solvent or the polymerization solvent, those similar to those described in the solution polymerization can be used, and alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, and tripropylene glycol can be used. The mixing ratio of the polymerization solvent is 20 to 100 parts by weight of the monomer mixture.
It is preferably 0 parts by weight or less. In addition, the monomer mixture may be blended with a thermal polymerization initiator, if necessary, and as the thermal polymerization initiator that can be used in this case, the same ones as those described in the solution polymerization can be used. . When the thermal polymerization initiator is blended with the monomer mixture, the amount is 0.001 to 5 parts by weight per 100 parts by weight of the monomer mixture.
It is preferably in parts by weight. Reaction temperature is 150-35
Preferably it is 0 ° C. When the temperature is lower than 150 ° C., the molecular weight of the obtained copolymer becomes too large,
The reaction rate may be slow, while 350 ° C
When the ratio exceeds the above range, a decomposition reaction may occur and the reaction solution may be colored. The 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. When the residence time is less than 2 minutes, when the unreacted monomer exceeds 60 minutes, productivity may be deteriorated.

The urethane prepolymer and / or curing agent used in the present invention may be used in combination with a compound having a small molecular weight and referred to as a chain extender, in addition to the polyol and acrylic polyol. It is also possible to arbitrarily adjust the physical strength of the final product. Such chain extenders include ethylene glycol, propylene glycol, butanediol, neopentyl glycol, 1,6-hexanediol, spiroglycol, bishydroxyethoxybenzene, methylenebis-
Glycols such as o-chloroaniline and diamines can be used.

As the urethane prepolymer used in the present invention, an isocyanate group-containing polyurethane prepolymer obtained by reacting the acrylic polyol with a polyisocyanate compound can be used in combination.

Further, it is possible to use a polyoxyalkylene polyol satisfying the above formula (1) in the curing agent used in the present invention.

The compounding ratio of the main component and the curing agent of the two-part curable composition of the present invention is such that the active hydrogen group-containing compound in the curing agent is added to the isocyanate group equivalent of the isocyanate group-containing polyurethane prepolymer in the main component. Is preferably set so that the number of active hydrogen groups becomes 0.7 to 1.5 equivalents. When the amount of active hydrogen groups is less than 0.7 equivalent, foaming may occur. When the amount is 1.5 equivalents or more, mechanical strength may decrease and residual tack on the surface may increase.

The ratio of the polyoxyalkylene polyol to the active hydrogen group-containing acrylic polymer in the two-part curable composition of the present invention is preferably from 10/90 to 90/10. If the amount of the active hydrogen group-containing acrylic polymer is larger than this, the residual tack on the surface becomes severe, the viscosity increases, and the workability decreases. If the amount is small, sufficient weather resistance tends to be not obtained.

In a preferred embodiment, a catalyst for adjusting the reaction between the NCO group and the active hydrogen group is added to the two-part curable composition of the present invention, if necessary. As such a catalyst, a catalyst well known to those skilled in the art can be used, and lead compounds such as lead naphthenate and lead octylate, tin compounds such as dibutyltin dilaurate and tin octylate, and tertiary amino compounds such as triethylenediamine Well-known compounds such as bismuth compounds can be exemplified as typical catalysts.

Further, the two-part curable composition of the present invention has a viscosity,
Fillers, thixotropic agents, plasticizers, solvents, adhesives, coloring agents, stabilizers, fungicides, etc. are mixed to control resin properties, resistance, etc. It can be a product such as wood, flooring, paint, etc., and these can be mixed with one or both of the two components constituting the composition.

The filler has the effect of adjusting the viscosity of the composition, improving the strength of the cured composition, and has the effect of coloring. As such a filler, it is possible to use inorganic, organic particles, short fibers, or powdery materials, such as precipitated silica, wollastonite, clay, talc, calcium carbonate, and surface treatment. Examples include calcium carbonate, acicular calcium carbonate, aluminum hydroxide, titanium oxide, microballoons, and the like.

Examples of the thixotropy imparting agent include ultrafine silica powder, hydrogenated castor oil, organic bentonite, calcium stearate and the like. Examples of the stabilizer include an antioxidant, an ultraviolet absorber, and a heat stabilizer.

The two-part curable composition of the present invention can be mixed by a method of kneading using a planetary mixer, a roll, a kneader, or the like, or a method of stirring and mixing using a dissolver, a twin-screw stirrer, or the like. is there.

[0047]

EXAMPLES Examples of the present invention will be described below together with comparative examples. In the following, “parts” means “parts by weight”. (Production Example of Acrylic Polymer) Acrylic Polymer A1: 100 parts of toluene was charged into a flask equipped with a dropping funnel, a stirrer, a nitrogen inlet tube, a thermometer, and a reflux condenser, and 100 ° C. while gently blowing nitrogen. The mixture was heated up to 93 parts of butyl acrylate and 1.6 parts of mercaptoethanol in 7 parts of 2-hydroxyethyl acrylate and 1.6 parts of 2,2′-azobisisobutyronitrile in toluene 20. What was dissolved in the part was dropped into the flask over 2 hours. After completion of the dropwise addition, stirring was continued for 1 hour at the same temperature to complete the polymerization.
When the polymerization rate was determined from the residual rate of the vinyl monomer by gas chromatography, it was 96%. Subsequently, the toluene was distilled off, and the residue was dried at 45 ° C. under reduced pressure to obtain a copolymer (A1) having a hydroxyl group only at one terminal and a side chain.
I got The number average molecular weight (Mn) of the polymer (A1) was measured by a standard polystyrene conversion method using gel osmotic pressure chromatography (GPC). The result was 4900, and the hydroxyl value measured according to JIS K 1557 was 43 mg KOH. / G.

Acrylic polymer A2: A flask equipped with a dropping funnel, a stirrer, a nitrogen inlet tube, a thermometer and a reflux condenser was charged with 153 parts of 2-hydroxyethyl disulfide, and 100 ° while gently blowing nitrogen gas.
The temperature was raised to C. A solution of 1.6 parts of 2,2′-azobisisobutyronitrile in 80 parts of butyl acrylate was added dropwise thereto over 2 hours. During dropping, keep the internal temperature at 105.
It was kept at ± 5 ° C. After completion of the dropwise addition, the mixture was further stirred at the same temperature for 1 hour to obtain a polymer mixture. Subsequently, the polymer mixture was transferred to a separating funnel, 100 parts of toluene was added, and the mixture was shaken well and allowed to stand for a while to remove the lower layer (2-hydroxyethyl disulfide) separated into two layers. Next, this toluene layer (upper layer) was washed three times with 200 parts of ion-exchanged water, 50 parts of sodium sulfate was added, and the toluene layer was dehydrated. Next, toluene was distilled off from the toluene layer to obtain an acrylic polymer (A2) having one hydroxyl group at both ends of the molecule. The number average molecular weight of the polymer (A2) was 4,400, and the hydroxyl value was 24 mgKOH / g. (Production Example of Polyoxyalkylene Polyol) Polyol P1: A dipropylene glycol-propylene oxide adduct having a molecular weight of 700 was used as an initiator, a zinc hexacyanocobaltate-glyme complex was used as a catalyst, and the molecular weight was 3000, and the total unsaturation was USV (meq / g). ) Is JI
The polyoxypropylene diol (P1) having a total degree of unsaturation of 0.013 as measured by the method described in SK1557 was obtained. Further, the hydroxyl value measured according to JIS K 1557 was 37.4 mgKOH / g.

Polyol P2: A glycerin-propylene oxide adduct having a molecular weight of 1,000 was used as an initiator, a zinc hexacyanocobaltate-glyme complex was used as a catalyst, and the molecular weight was 5000, the total degree of unsaturation was 0.014, and the hydroxyl value was 3
3.7 mg KOH / g of polyoxypropylene triol (P2) was obtained.

Polyol P3: A dipropylene glycol-propylene oxide adduct having a molecular weight of 700 was used as an initiator, and a zinc hexacyanocobaltate-t-butanol complex was used as a catalyst to have a molecular weight of 8,000 and a total unsaturation of 0.00.
5. Polyoxypropylene diol (P3) having a hydroxyl value of 14.0 mgKOH / g was obtained.

Polyol P4: Dipropylene glycol as initiator, potassium hydroxide as catalyst, molecular weight 30
00, total unsaturation 0.062, hydroxyl value 37.4mg
KOH / g of polyoxypropylene diol (P4) was obtained.

Polyol P5: Using glycerin as an initiator, potassium hydroxide as a catalyst, molecular weight of 5,000, total degree of unsaturation of 0.065, and hydroxyl value of 33.7 mgKOH / g
Of polyoxypropylene triol (P5) was obtained. (Production Example of Isocyanate Group-Containing Polyurethane Prepolymer) Prepolymer U1: 348 parts of 2,4-tolylene diisocyanate and 3000 parts of polyol (P1) were heated at 100 ° C.
For 10 hours to obtain a urethane prepolymer (U1) having an isocyanate group at the molecular terminal. The terminal NCO groups of the prepolymer were 2.5% by weight.

Prepolymer U2: 672 parts of isophorone diisocyanate, 5000 parts of polyol (P2), and 0.3 part of a urethanization catalyst (dibutyltin dilaurate)
The reaction was performed at 00 ° C. for 10 hours to obtain a urethane prepolymer (U2) having an isocyanate group at a molecular terminal. The terminal NCO groups of the prepolymer were 2.2% by weight.

Prepolymer U3: 348 parts of 2,4-tolylene diisocyanate was reacted with 3000 parts of polyol (P4) at 100 ° C. for 10 hours to obtain a urethane prepolymer (U3) having an isocyanate group at a molecular terminal. The terminal NCO groups of the prepolymer were 2.5% by weight.

Prepolymer U4: 672 parts of isophorone diisocyanate, 5000 parts of polyol (P5), and 0.3 part of a urethanization catalyst (dibutyltin dilaurate)
The reaction was performed at 00 ° C. for 10 hours to obtain a urethane prepolymer (U4) having an isocyanate group at a molecular terminal. The terminal NCO groups of the prepolymer were 2.2% by weight. (Production Example of Curing Agent) Curing Agent K1: 50 parts of acrylic polymer (A1), 50 parts of polyoxypropylene diol (P3), 190 parts of surface-treated calcium carbonate (Calfine 500; manufactured by Maruo Calcium Co., Ltd.), titanium oxide 20 parts, 30 parts of a plasticizer (dioctyl phthalate), 0.1 part of a curing catalyst (dibutyltin dilaurate), and 3 parts of a weathering stabilizer (Tinuvin B75) are uniformly kneaded at room temperature with a planetary mixer, and then 100 parts under reduced pressure. At room temperature for 1 hour to perform a dehydration operation.
1) was obtained.

Curing agent K2: Acrylic polymer (A2) 1
00 parts, surface-treated calcium carbonate (Calfine 50
0; 190 parts of Maruo Calcium Co., Ltd.), 20 parts of titanium oxide, 30 parts of a plasticizer (dioctyl phthalate), 0.1 part of a curing catalyst (dibutyltin dilaurate), and 3 parts of a weathering stabilizer (tinuvin B75) 3 parts. After kneading uniformly at room temperature at room temperature, the mixture was kneaded under reduced pressure at 100 ° C. for 1 hour to perform a dehydration operation to obtain a curing agent (K2).

Curing agent K3: 100 parts of an acrylic polymer (ARUFONUH-2000, molecular weight: 13,000, hydroxyl value: 20 mgKOH / g; manufactured by Toagosei Co., Ltd.) obtained by a high-temperature continuous polymerization method, surface-treated calcium carbonate (calcium) Fine 500) 190 parts, titanium oxide 20 parts,
30 parts of a plasticizer (dioctyl phthalate), 0.1 part of a curing catalyst (dibutyltin dilaurate), and 3 parts of a weathering stabilizer (tinuvin B75) are uniformly kneaded at room temperature with a planetary mixer, and then mixed at 100 ° C. under reduced pressure. The mixture was kneaded for a time and a dehydration operation was performed to obtain a curing agent (K3).

Curing agent K4: Acrylic polymer (A2) 1
00 parts, surface-treated calcium carbonate (Calfine 50
0) 190 parts, 20 parts of titanium oxide, 30 parts of a plasticizer (dioctyl phthalate), 1 part of a curing catalyst (dibutyltin dilaurate), and 3 parts of a weathering stabilizer (tinuvin B75) are uniformly kneaded at room temperature with a planetary mixer. , 10 under reduced pressure
The mixture was kneaded at 0 ° C. for 1 hour to perform a dehydration operation to obtain a curing agent (K4).

Curing agent K5: 100 parts of polyoxypropylene triol (P2), 190 parts of surface-treated calcium carbonate (Calfine 500), 20 parts of titanium oxide, 30 parts of plasticizer (dioctyl phthalate), curing catalyst (dibutyltin dilaurate) 0.1 parts, weathering stabilizer (Tinuvin B7
5) After uniformly kneading 3 parts at room temperature with a planetary mixer, the mixture was kneaded under reduced pressure at 100 ° C. for 1 hour to perform a dehydration operation to obtain a curing agent (K5). (Evaluation method) [Residual tack] The tack on the surface of the test piece was evaluated by finger erosion. In the evaluation, ○ was weak and × was strong. [Mechanical properties] A test piece was measured according to JIS K6301. [Weather resistance test] The test piece was irradiated for 1000 hours using a sunshine weather meter tester. For the evaluation of weather resistance, the surface of the test piece was visually observed to determine the presence or absence of deterioration. The evaluation was as follows: 変 化 No change and × crack generation. Examples 1 to 3 The main composition and the curing agent were mixed at the compounding ratio shown in Table 1, and the defoamed composition was allowed to stand at 23 ° C. for 7 days, and then allowed to stand at 50 ° C. for 7 days to cure to prepare a test piece Then, residual tack, mechanical properties, and weather resistance were evaluated. Table 1 shows the results. As shown in Table 1, the cured product obtained from the composition of the present invention had excellent mechanical strength, sufficient elongation, low residual tack on the surface, and excellent weather resistance. Comparative Examples 1 to 4 When the polyol component in the prepolymer, which is the main agent of Examples 1 to 3, was replaced with a polyol having a high total unsaturation, the residual tack on the surface of the cured product was strong, and the stain resistance was poor. there were. Also, even when the modulus was increased by 100% as in Comparative Example 4, the residual tack was not significantly improved. Comparative Example 5 When only the active hydrogen group-containing compound in the curing agent of Example 1 was polyoxypropylene triol, the cured product was inferior in weather resistance.

[0060]

[Table 1]

[0061]

According to the present invention, the polyisocyanate compound has a hydroxyl value OHV (mgKOH / g) of 5 to 60 and a total unsaturation USV (meq / g) of USV ≦ 1.2 / O.
Curing obtained from a two-part curable composition comprising a main agent containing an isocyanate group-containing polyurethane prepolymer obtained by reaction with a polyoxyalkylene polyol satisfying HV and a curing agent containing an active hydrogen group-containing acrylic polymer The material is excellent in weather resistance and mechanical strength, has sufficient elongation, and has little residual tack on the surface, so is excellent in stain resistance.

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 4H017 AA03 AB01 AB06 AC16 AC19 4J034 BA07 DA01 DB04 DB05 DB07 DG02 DG03 DG04 DG05 DG18 DG29 DP18 HA01 HA02 HA07 HA08 HB01 HB11 HB15 HC03 HC12 HC13 HC17 HC22 HC45 HC46 HC52 HC54 HC61 HC HC67 HC68 HC70 HC71 HC73 JA42 QA02 QA05 QA07 QB13 RA07 RA08 RA10

Claims (3)

[Claims] 1. A polyisocyanate compound and a hydroxyl value OH
V (mgKOH / g) is 5 to 60 and total unsaturation is US
A main agent containing an isocyanate group-containing polyurethane prepolymer obtained by a reaction with a polyoxyalkylene polyol whose V (meq / g) satisfies the following general formula (1): USV ≦ 1.2 / OHV (1); And a curing agent containing an acrylic polymer. 2. The active hydrogen group-containing acrylic polymer has a number average molecular weight of 1,000 to 50,000 and a hydroxyl value of 1
The two-part curable composition according to claim 1, wherein the composition is 0 to 400 mgKOH / g. 3. The composition according to claim 1, wherein the ratio of the polyoxyalkylene polyol to the active hydrogen group-containing acrylic polymer is 10/10.
The two-part curable composition according to claim 1, wherein the composition is 90 to 90/10.