JPS6274982A - Elastic sealant - Google Patents

Abstract

PURPOSE:To provide an elastic sealant which is excellent in weather resistance and workability and which comprises an acryl-polyoxyalkylene isocyanate component as a main ingredient and a particular mixture as a curing agent. CONSTITUTION:Polyoxyalkylene polyol is reacted with an org. diisocyanate to obtain a low-molecular alkyl (meth)acrylate isocyanate component (I). To polyoxyalkylene polyol (A) is added a polymerization material (B) comprising an unsatd. monomer having a functional group capable of reacting with an isocyanate group, an unsatd. monomer of the formula, and a polymerization initiator or a chain transfer agent having a functional group capable of reacting with an isocyanate group. The polymerization is allowed to proceed, thereby obtaining an alkyl (meth)acrylate copolymer. The copolymer is mixed with a product obtd. by grafting the copolymer on polyoxyalkylene polyol and polyoxyalkylene polyol to obtain a mixture (II). The titled sealant is obtd. by using the component (I) as a main ingredient and the component (II) as a curing agent.

Description

[Detailed description of the invention] [Industrial application field] This invention relates to an elastic sealant with excellent weather resistance.

[Conventional technology]

Sealants filled into the joints of buildings must have elastic properties that allow them to expand and contract in response to thermal changes in the building materials that make up the joints, and they must also have the ability to expand and contract in response to thermal changes in the building materials that make up the joints. It is desirable that it does not contain any scattered substances.

Such a sealant is mainly composed of a prepolymer having an isocyanate group at the molecular end obtained by reacting a polyoxyalkylene polyol with an organic diisocyanate, a polyoxyalkylene polyol or polyamines as a curing agent, and other fillers as necessary. Urethane sealants containing softeners, stabilizers, etc. are used.

However, such conventional urethane sealants have problems in weather resistance, and have the drawback that cracks occur on the sealant surface when exposed outdoors for a long period of time.

On the other hand, recently, acrylic sealants containing a low molecular weight (meth)acrylic acid alkyl ester copolymer having a functional group as a main component have become known. This type of sealant has the advantage of being excellent in weatherability, durability, heat resistance, etc.

[Problems to be Solved by the Invention] However, this acrylic sealant has a drawback in that it is difficult to adjust the workability of the sealant and the properties of the cured sealant, particularly the elastic properties such as modulus and elongation. In other words, in order to obtain a cured sealant with low modulus and high elongation, it is necessary to increase the molecular weight of the (meth)acrylic acid alkyl ester-based low molecular weight copolymer, but increasing the molecular weight increases the viscosity and makes it difficult to work with. Another drawback is that the surface of the cured product may become sticky.

Therefore, the present invention solves the above-mentioned problem that it is difficult to adjust the construction workability and the low tackiness and elastic properties of the surface of the cured sealant with sealants that have excellent weather resistance. The purpose of the present invention is to obtain an acrylic elastic sealant which has sufficient elastic properties for joint filling, has a cured product surface with low tackiness, has excellent weather resistance, and is easy to apply.

Means for Solving Problem E] As a result of intensive studies to solve the above problems, the inventors have found that a polyoxyalkylene isocyanate component or an alkyl estyle (meth)acrylate isocyanate component is used as the main ingredient. (meth) in the presence of polyoxyalkylene polyol as a curing agent.
A copolymer that has a high molecular weight and has a large number of functional groups that can react with isocyanate groups introduced per molecule by copolymerizing an unsaturated monomer whose main component is an acrylic acid alkyl ester. The present invention was completed based on the knowledge that an industrially useful elastic sealant that solves the above-mentioned problems can be obtained by using a mixture consisting of a graft product of a polymer, a polyoxyalkylene polyol, and a polyoxyalkylene polyol. reached.

That is, this invention provides: a) a polyoxyalkylene isocyanate component having an isocyanate group at the molecular end obtained by reacting a polyoxyalkylene polyol with an organic diisocyanate, or an isocyanate group having an average of about one isocyanate group at the end of the molecule and any number of isocyanate groups in the molecule; A (meth)acrylic acid alkyl ester-based low molecular weight copolymer isocyanate component (hereinafter referred to as an acrylic isocyanate component) having an average of one or more molecules at 5 to 60% by weight of a polyoxyalkylene polyol, B) a) an unsaturated monomer having a functional group capable of reacting with an isocyanate group, and b) the general formula; % formula % (in the formula, R is hydrogen Or methyl group, R2 has 2 carbon atoms
~14 alkyl group) Unsaturated monomer represented by (however, up to 50% by weight may be substituted with other copolymerizable unsaturated monomer)
and c) 95 to 40% by weight of a polymerization raw material consisting of a polymerization initiator and/or a chain transfer agent that generates a functional group that reacts with isocyanate groups, and is capable of reacting with isocyanate groups, resulting from a polymerization reaction. A (meth)acrylic acid alkyl ester copolymer having an average of about 1 functional group at the end of the molecule and about 5 to 20 functional groups at any position within the molecule and a number average molecular weight of 25,000 to 200,000. The present invention relates to an elastic sealant that uses a mixture of a graft of a copolymer and a polyoxyalkylene polyol and a polyoxyalkylene polyol (hereinafter referred to as an acrylic-polyoxyalkylene mixture) as a curing agent.

As described above, the elastic sealant of the present invention is a two-component urethane type using a polyoxyalkylene isocyanate component or an acrylic isocyanate component as the main ingredient and an acrylic-polyoxyalkylene mixture as the curing agent, Since this sealant has the properties of an acrylic sealant, it has excellent properties such as heat resistance, durability, and weather resistance.

In addition, the above acrylic-polyoxyalkylene mixture has an average of about 5 to 20 functional groups per molecule that have a high molecular weight and can react with isocyanate groups obtained in the above reaction.
Since it is a mixture containing a (meth)acrylic acid alkyl ester-based copolymer having a large number of copolymers, when the main ingredient is cured using this as a curing agent, due to the high molecular weight of the copolymer, Low modulus, high elongation.

It can highly satisfy the elastic properties required for architectural sealants, such as low hardness.

Moreover, since the above-mentioned copolymer has a large number of functional groups per molecule, it is possible to ensure the reaction between the copolymer and the acrylic or polyoxyalkylene base material, so that no reaction occurs after curing. Because there is no risk of ingredients remaining,
It is possible to form a cured sealant with excellent stain resistance by suppressing tackification of the surface of the cured product.

Furthermore, if the above-mentioned copolymer has a high molecular weight, there is a concern that construction workability will be lowered due to an increase in viscosity, but this concern can be avoided by using the polyoxyalkylene polyol used when synthesizing the above-mentioned copolymer. That is, since this polyol originally has a lower viscosity than acrylic ones and has a molecular weight in the range of 400 to 6,000, when the above copolymer is obtained in the presence of this polyol, , together with the formation of a graft body of both, can greatly contribute to lowering the viscosity of the mixture.

Therefore, by using the above-mentioned acrylic-polyoxyalkylene mixture as a curing agent in combination with a main ingredient consisting of a polyoxyalkylene isocyanate component or an acrylic isocyanate component, the viscosity of the sealant can be adjusted without using a solvent. It can be easily adjusted, which greatly improves construction workability, and there is no need to worry about eyesightening after construction.

In addition, in the following, acrylic copolymer and acrylic low molecular weight copolymer refer to (meth)acrylic acid alkyl ester copolymer and the same low molecular weight copolymer, respectively. This refers to copolymers and low molecular weight copolymers of the same as raw monomers.

[Structure and Function of the Invention] The elastic sealant of the present invention is characterized in that an acrylic-polyoxyalkylene mixture is used as a curing agent for a main component consisting of a polyoxyalkylene isocyanate component or an acrylic isocyanate component. This mixture is composed of an acrylic copolymer, a polyoxyalkylene polyol, and a grafted product of both, and is prepared as follows.

That is, it can be prepared by adding a specific amount of the polymerization raw material as the B component to the polyoxyalkylene polyol as the A component and causing a polymerization reaction.

The polyoxyalkylene polyol as component A is obtained by polymerizing a polyhydric alcohol and an alkylene oxide, and has a number average molecular weight of 400 to 6, and has hydroxyl groups as functional groups capable of reacting with isocyanate groups at least at both ends of the molecule. ,000, preferably 400 to 4,000.

If the molecular weight of this polyol is less than 400, the modulus of the cured sealant product tends to increase and the surface of the cured product tends to become sticky, and the sealant becomes more hygroscopic or water-absorbing, resulting in poor storage stability, making it unsuitable. be. Moreover, if the molecular weight of the polyol exceeds 6,000, it will be difficult to contribute to lowering the viscosity of the sealant, which is still inappropriate.

Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, glycerin, pentaerythritol, and trimethylolpropane, but diols such as ethylene glycol and propylene glycol, and triols such as glycerin are preferably used.

Examples of the alkylene oxide mentioned above include propylene oxide, ethylene oxide, butylene oxide, etc., and these may be used alone or in a mixture of two or more.

The polymerization raw material as component B consists of a) an unsaturated monomer having a functional group capable of reacting with an isocyanate group, and b) the following general formula; Carbon number 2
~14 alkyl group) Unsaturated monomer represented by (however, up to 50% by weight may be substituted with other copolymerizable unsaturated monomer)
and c) a polymerization initiator and/or chain transfer agent having a functional group capable of reacting with an isocyanate group.

The above monomer a is an unsaturated monomer having a carboxyl group, a hydroxyl group, etc., and specifically includes acrylic acid, methacrylic acid, maleic acid, 2-hydroxyethyl acrylate,
Examples include 2-hydroxyethyl methacrylate.

In addition, the above b monomer refers to acrylic acid or methacrylic acid having 2 to 14 carbon atoms, such as ethyl, n-butyl, isobutyl, 1-ethylpropyl, 2-methylpentyl, 2-ethylbutyl, 2-ethylhexyl, etc. 100 to 50 of one or two or more alkyl esters of
% by weight and other unsaturated monomers copolymerizable with these,
For example, it contains 0 to 50% by weight of vinyl acetate, vinyl propionate, acrylonitrile, methyl methacrylate, styrene, acrylamide, and the like.

If the amount of other copolymerizable unsaturated monomers exceeds 50% by weight, weather resistance will decrease, which is not preferable.

Furthermore, as a polymerization initiator having a functional group that reacts with the isocyanate group of component C, there are polymerization initiators having a carboxyl group, a hydroxyl group, etc., and specifically, azobiscyanovaleric acid, peroxide oxalic acid, Examples include azovissia/pentanol.

Furthermore, as chain transfer agents having functional groups that can react with isocyanate groups, there are chain transfer agents having carboxyl groups, hydroxyl groups, amino groups, etc., and specifically, thioglycolic acid, 2-mercaptoacetic acid, 2-mercaptoacetic acid, and 2-mercaptoacetic acid. ethanol,
Examples include 2-amino/ethanethiol.

Among these polymerization raw materials, the usage ratio of a monomer and b monomer is such that the usage amount of a monomer is 1/10 of the usage amount of b monomer.
Considering the degree of polymerization and polymerization ratio within the range of ~1/300 mole, the acrylic copolymer has on average a functional group capable of reacting with the isocyanate group derived from the a monomer at any position within the molecule. It is determined that about 4 to 19 pieces are introduced, preferably about 5 to 15 pieces on average.

That is, the total number of functional groups including the above number of functional groups and an average of about 1 functional group introduced at the end of the molecule derived from the C component described later, that is, the total number of functional groups per molecule of the copolymer is about 5 to 2 on average.
The usage ratio of a and b monomers is determined so that the number of monomers is 0. Here, if the total number of functional groups is less than about 5 on average, no reduction or disappearance of surface tackiness of the cured sealant can be expected, and if it exceeds about 20 on average,
Both methods are unsuitable, as they have problems such as an increase in the modulus of the cured sealant.

As component C, the above-mentioned polymerization initiator and chain transfer agent may be used in combination, or either one may be used, but the amount used is such that on average about one isocyanate is present at the molecular terminal of the copolymer. The b monomer 10
The range is 0.03 to 1.0 parts by weight relative to 0 parts by weight. The reason why an average of about one functional group capable of reacting with an isocyanate group is introduced at the end of the molecule is to obtain good results in the elastic properties of the cured sealant.

The polymerization reaction may be carried out according to a conventional method by adding the polymerization raw material as the B component to the polyoxyalkylene polyol as the A component, and in this case, the A component is 5 to 60% by weight.
The mixing ratio of components A and B should be determined so that the amount of component B is preferably 95 to 40% by weight, preferably 90 to 50% by weight. If the amount of component A is less than 5% by weight, the viscosity of the sealant cannot be lowered, and if it exceeds 60% by weight, there is a risk that the weather resistance, heat resistance, etc. of the cured sealant may deteriorate.

Polymerization is radical polymerization, and depending on what is used as the C component in the polymerization raw material, ordinary polymerization initiators, chain transfer agents,
For example, benzoyl peroxide, α·d-azobisisobutyronitrile, lauryl mercaptan, and the like can be used as appropriate.

This polymerization reaction is usually carried out using a bulk polymerization method that does not use a solvent, and if unreacted monomers remain after the polymerization reaction, it will cause odor during sealant application and eye discoloration after application. Temperature 5 so that as little as possible remains
This is carried out by adjusting polymerization conditions such as time.

The polymerization reaction product obtained in this manner is an acrylic copolymer having an average of about 1 functional group at the end of the molecule and about 4 to 19 functional groups at arbitrary positions within the molecule, which reacts with isocyanate groups. It is an acrylic-polyoxyalkylene mixture consisting of a graft product of a polymer and a polyoxyalkylene polyol and a polyoxyalkylene polyol that does not participate in hyphraft. Here, the above copolymer has a number average molecular weight of 25,000 to 200,000.
．． Particularly preferably, it needs to be set in the range of 30,000 to 150,000. In other words, when the number average molecular weight is less than 25,000, the cured sealant must have low modulus, high elongation, and low hardness. Adjustment becomes difficult. Furthermore, if the number average molecular weight exceeds 200.000, it is difficult to reduce the viscosity of the sealant, and furthermore, due to the difference in chain transfer constant of the monomers, it is difficult to reduce the tackiness of the surface of the cured sealant. It also becomes difficult to achieve non-adhesive properties.

The above-mentioned molecular weight and the above-mentioned number of functional groups per molecule can be measured after separating each polymer component constituting the polymer mixture after the above-mentioned polymerization reaction, but this operation is quite troublesome and is not necessarily practical. I can't say that. Therefore, more simply, the above-mentioned polymerization reaction is carried out using exactly the same polymerization raw materials and under the same conditions except that it is separately carried out in the absence of component A, that is, polyoxyalkylene polyol, and the acrylic resin obtained by this method is The molecular weight and number of functional groups of the system copolymer may be measured, and these values may be regarded as the molecular weight and number of functional groups of the copolymer obtained by polymerization reaction in the presence of component A. Even when estimated in this way, there is almost no significant difference between the measured value and the actual value.

In this invention, the polyoxyalkylene isocyanate component or the acrylic isocyanate component may be used alone, or both may be used as the main component to be combined with the curing agent made of the acrylic-polyoxyalkylene mixture prepared by the above method. You may mix and use in arbitrary ratios.

The above polyoxyalkylene isocyanate component is
An organic diisocyanate is added to a polyoxyalkylene polyol having a number average molecular weight of about 400 to 6,000, which is the same as the component A used to obtain the curing agent, and the number of isocyanate groups is 1,8 to 1 per equivalent of hydroxyl group in the polyol. 2
．． It is obtained by reacting at a ratio of 3 equivalents, preferably 1.9 to 2.1 equivalents, and has an isocyanate group at the end of the molecule.

The above-mentioned organic diisocyanate is not particularly limited, but it is preferable to use a diisocyanate such as 1,3-bisisocyanate methyl cyclohexane and inphorone diisocyanate, which will not cause yellowing of the cured sealant. Others 2,4-tolylene diisocyanate, 2,6-
Examples include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, and the like.

The above acrylic isocyanate component has a number average molecular weight of 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 type type type type type type type type type type form. It is obtained by reacting an acrylic low molecular weight copolymer of about 500 to 6,000 with the same organic diisocyanate as above in the same manner as above, and the above reaction results in an average of about 1 isocyanate group at the end of the molecule. And, on average, about 1 or more, and usually up to 2, are introduced at any position within the molecule.

The above acrylic low molecular weight copolymer used here was prepared in the same manner as above except that the polyoxyalkylene polyol as component A was not used in the method for preparing the acrylic and polyoxyalkylene mixture as the curing agent. Obtainable.

That is, by using monomers a and b as polymerization raw materials and a polymerization initiator and/or chain transfer agent having a functional group capable of reacting with an isocyanate group as component C, isocyanate groups are added to the copolymer molecule. The reactive functional group is introduced as described above, and the molecular weight is as described above.
It can be easily obtained by adjusting the amounts of the C component and the monomer a, and by adjusting the polymerization conditions as appropriate.

In the elastic sealant of the present invention, the blending ratio of the base agent and the curing agent is usually such that the amount of functional groups that react with the isocyanate groups in the curing agent is 0.1 to 1 equivalent of isocyanate groups in the base agent.
It is preferable to adjust the amount to 8 to 1.4 equivalents.

The elastic sealant of the present invention can contain fillers and catalysts required for general sealants. Furthermore, pigments, anti-aging agents, anti-mold agents, antioxidants, ultraviolet absorbers, ozone deterioration inhibitors, thixotropic agents, etc. can be added as necessary.

The above-mentioned fillers improve the strength of the cured sealant, and include, for example, calcium carbonate, silica powder, talc, glass powder, titanium oxide, and the like. The amount added is preferably 30 to 200 parts by weight per 100 parts by weight of the curing agent. If the amount added is too small, it will be difficult to obtain the desired strength, and if it is too large, the elongation of the cured product will be poor, so it is preferable. do not have.

Further, as the catalyst, organometallic compounds such as dibutyltin dilaurate, monobutyltin oxide, and dioctyltin dilaurate, and amine derivatives such as triethylenediamine, triethylenetetramine, and diaminodiphenylmethane can be used. These addition amounts are hardening agent 1
The elastic sealant of the present invention having the above-mentioned composition of 0.001 to 5.00 parts by weight has the advantage that it has good workability during application and does not cause eye loss after application. Furthermore, since the sealant after curing has the characteristics of an acrylic elastic material, it has excellent weather resistance, durability, and heat resistance, and it easily follows changes in joint width and does not cause cracks. do not have. Furthermore, the surface of the cured sealant does not become sticky, and therefore there is less staining due to adhesion of dust and the like.

[Effects of the Invention] As described above, since the elastic sealant of the present invention can be adjusted to a low viscosity without using a solvent, it is possible to improve workability during construction, and there is no fear of eye loss after construction.
Moreover, the cured product has excellent weather and heat resistance as an acrylic sealant.

It has durability, low modulus, and low hardness.

It has elastic properties such as high elongation, which is very suitable for use as architectural sealants, and it also has various advantages such as the cured product surface becomes low or non-adhesive and can improve stain resistance. ing.

[Example] Next, an example of the present invention will be described. In the following, parts mean parts by weight. In addition, "part weight" means number average molecular weight, and "%" means weight %.

Example 1 An acrylic compound composition consisting of 100 parts of n-butyl acrylate, 08 parts of acrylic acid, and 0.08 parts of mercaptoacetic acid was prepared.

30% of this blended composition and 20 parts of polypropylene glycol having a molecular weight of 1,000 were placed in a 200 CC four-necked flask, and the contents were heated to 70°C while stirring and replacing the inside of the flask with nitrogen.

After purging with air for about 60 minutes, 0.1 part of α·α'-azobisisobutyronitrile was added, and heat generation immediately started. After this heat generation became mild, 0.2 part of α・α′-azobisisobutyronitrile was added to the remainder of the above-mentioned composition and was gradually added to the flask over a period of about 3 hours using a dropping funnel. Ta. The point at which no heat generation was observed thereafter was defined as the end point of polymerization.

The acrylic-polyoxyalkylene mixture thus obtained had a viscosity of 150 poise (30°C, 2 rpm) as measured by a B-type rotational viscometer.

For reference, the polymerization rate of the acrylic copolymer obtained by carrying out the above polymerization reaction in exactly the same manner as above except that 20 parts of polypropylene glycol was not used was 98.4%.
, viscosity measured by B-type rotational viscometer (30°C r 2 r pm
) is 1,400 poise, molecular weight (by vapor pressure osmosis method)
was 116,000. The number of functional groups capable of reacting with isocyanate groups per molecule was 13.8.

To 100 parts of this acrylic-polyoxyalkylene mixture, 100 parts of calcium carbonate, 23 parts of titanium dioxide, 1.6 parts of Disparon 360ON (polyether ester type surfactant manufactured by Shusui Kasei Co., Ltd.), 0 parts of dibutyl tin dilaure) 0.5 parts were blended, premixed using a kneader, and further kneaded using three rolls to obtain a curing agent blended system.

Method-S: After dehydrating 100 parts of polypropylene glycol with a molecular weight of 2,000 as the main ingredient, 20 parts of 1,3-bisisocyanatomethylcyclohexane and 0.005 parts of dibutyltin dilaure were added and reacted at 80°C for 5 hours. Using the polyoxyalkylene isocyanate component (isocyanate group content 3.8%) obtained by
The elastic sealant of the present invention was prepared by blending 225 parts of the curing agent compounding system with 100 parts of this polyoxyalkylene isocyanate component so that the curing agent was 100 parts per 00 parts.

Example 2 Acrylic compound composition consisting of 50 parts of n-butyl acrylate, 50 parts of ethyl acrylate, 1 part of 2-hydroxyethyl acrylate, and 0.05 part of 2-mercaptoethanol, and polypropylene glycol 40 with a molecular weight of 4,000. An acrylic-polyoxyalkylene mixture was obtained in the same manner as in Example 1. This mixture had a viscosity of 120 boids (30°C, 2 rpm) as measured by a B-type rotational viscometer.

For reference, the polymerization rate of the acrylic copolymer obtained by carrying out the above polymerization reaction in exactly the same manner as above except that 40 parts of polypropylene glycol was not used was 98.5%.
, the viscosity measured by a B-type rotational viscometer (30°C, 2 rpm) is 1
, 900 poise, molecular weight (by vapor pressure osmosis method) is 15
The number of functional groups capable of reacting with isocyanate groups per molecule was 14.5.

To 100 parts of this acrylic-polyoxyalkylene mixture, 150 parts of calcium carbonate, 15 parts of titanium dioxide, 2 parts of Disparon 360ON (mentioned above), 0.1 part of dibutyltin dilaurate, and 01 part of carbon black were added to a kneader. The mixture was sufficiently kneaded using this roll to form a curing agent-blended system.

On the other hand, an acrylic isocyanate component used as a main component was obtained as follows. That is, an acrylic low molecular weight copolymer was obtained in the same manner as in Example 1 using 9.5 parts of n-butyl acrylate, 5 parts of styrene, 3 parts of 2-hydroxyethyl acrylate, and 2 parts of 2-mercaptoethanol. Ta. This copolymer has a polymerization rate of 100%, a viscosity of 80 poise (30°C, 2 rpm) measured by a B-type rotational viscometer, a molecular weight of 4.200 measured by vapor pressure osmosis, and a number of hydroxyl groups per molecule of 2.08. It was.

After dehydrating 100 parts of this acrylic low molecular weight copolymer, 9 parts of 2,4-tolylene diisocyanate and 0.002 parts of dibutyltin dilaurate were added, and the mixture was reacted at 80°C for 5 hours to form an acrylic resin into which isocyanate groups had been introduced. System isocyanate component (isocyanate group content 2.05%)
I got it.

The above-mentioned curing agent blend system 640@ was added to 100 parts of this acrylic isocyanate component so that the amount of curing agent was about 242 parts with respect to 100 parts of this main agent to obtain an elastic sealant of the present invention.

Regarding the elastic sealants obtained in Examples 1 and 2 above,
When properties were evaluated based on JIS-A-5758, all sealants had 0 slump and no staining properties. Furthermore, the extrudability and tensile adhesion properties were as shown in the following table.

Furthermore, when the cured products of the elastic sealants of Examples 1 and 2 were subjected to an outdoor exposure test (6 months), no surface cracks were found in any of them.

Patent applicant: Nitto Electric Industry Co., Ltd. Agent: Patent attorney Moto Kunio Neikan, t”IC,7,′,
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Claims (1)

[Claims] (1) A) A polyoxyalkylene isocyanate component having an isocyanate group at the molecular end obtained by reacting a polyoxyalkylene polyol with an organic diisocyanate, or an isocyanate group at the molecular end of about 1 on average
The main ingredient is a (meth)acrylic acid alkyl ester-based low molecular weight copolymer isocyanate component having an average of one or more alkyl esters at any arbitrary position within the molecule, and (b) a polyoxyalkylene having an A number average molecular weight of 400 to 6,000. 5 to 60% by weight of the polyol, B) a) an unsaturated monomer having a functional group capable of reacting with an isocyanate group, and b) the following general formula; ▲ mathematical formula, chemical formula,
There are tables, etc. ▼ (In the formula, R_1 is hydrogen or a methyl group, R_2 is an alkyl group having 2 to 14 carbon atoms) (Can be substituted with unsaturated monomer)
and c) 95 to 40% by weight of a polymerization raw material consisting of a polymerization initiator and/or a chain transfer agent having a functional group capable of reacting with an isocyanate group. A (meth)acrylic acid alkyl ester copolymer having an average of about 1 group at the end of the molecule and about 4 to 19 groups at any position within the molecule and a number average molecular weight of 25,000 to 200,000; An elastic sealant whose curing agent is a mixture of a graft product of a polymer and a polyoxyalkylene polyol, and a polyoxyalkylene polyol.