JPH0222781B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to an elastic sealant with excellent weather resistance. Sealants filled into the joints of buildings must have elastic properties such as low modulus and high elongation so that they can expand and contract in response to thermal changes in the building materials that make up the joints. It is desirable that the material does not contain substances such as organic solvents that are dispersed into the atmosphere. 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 urethane sealants have insufficient weather resistance and have the disadvantage that cracks occur on the sealant surface when exposed outdoors for a long time. Polyacrylic sealants, on the other hand, have the advantage of being excellent in weather resistance, colorability, and durability, but on the other hand, they are inelastic and have high viscosity, so they can only be obtained in emulsion or organic solvent types. do not have. For this reason, when this type of sealant is filled into the joint, cracks and gaps are likely to occur because it cannot follow changes in the joint width over time due to thermal effects, etc. It is often thin and does not function well as a sealant. Additionally, attempts have been made to improve the bending resistance and weather resistance of urethane sealants by using polymers obtained by polymerizing ethylenically unsaturated monomers in polyoxyalkylene polyols as curing agents. There is. However, with this method, it is difficult to obtain an elastic sealant for construction that has well-balanced properties such as modulus, weather resistance, and adhesiveness. In other words, depending on the type and amount of the ethylenically unsaturated monomer used, the weather resistance of the sealant may be improved but the modulus may be high, or the sealant may have a low modulus but be sticky and therefore be susceptible to contamination with dust. There are drawbacks such as. The inventors do not have the above drawbacks,
As a result of various studies aimed at obtaining an elastic sealant for filling joints in buildings, etc., which has a good balance of adhesion, modulus, elongation, strength, etc. and also has excellent weather resistance, this invention was developed. . That is, in this invention, the average molecular weight is 300~
6000, polyethylene glycol, polypropylene glycol, polyoxypropylene polyol, or polyoxyethylene-polyoxypropylene polyol, is reacted with an organic diisocyanate. Polyoxyalkylene isocyanate component or average molecular weight of 1500~
The main ingredient is an acrylic low molecular weight copolymer isocyanate component (hereinafter referred to as the acrylic isocyanate component), which has an average of about 1 isocyanate group at the end of the molecule and about 1 at any position within the molecule, and has an average molecular weight of a) in the presence of 5 to 30 parts by weight of at least one polyoxyalkylene polyol selected from polyethylene glycol, polypropylene glycol, polyoxypropylene polyol or polyoxyethylene-polyoxypropylene polyol having a A functional unsaturated monomer having one carboxyl group or hydroxyl group in the molecule as a functional group capable of reacting with an isocyanate group, and b) a (meth)acrylic acid alkyl ester with an alkyl group having 2 to 14 carbon atoms. 50% by weight and at least one unsaturated monomer selected from vinyl acetate, vinyl propionate, acrylonitrile, methyl methacrylate, styrene or acrylamide 0-50
A mixture with a main monomer consisting of % by weight,
100 parts by weight of an acrylic monomer mixture in which the amount of the former A monomer used is in the range of 1/10 to 1/500 mole of the latter B monomer used, and 100 parts by weight of the above B monomer A polymerization initiator having a carboxyl group or hydroxyl group as a functional group capable of reacting with an isocyanate group or a chain transfer agent having a carboxyl group, hydroxyl group or amino group as the same functional group in a ratio of 0.3 to 20 parts by weight based on the weight part. The invention relates to an elastic sealant that uses an acrylic-polyoxyalkylene composition copolymerized with a curing agent as a curing agent. The elastic sealant of the present invention is a two-component urethane type and has the properties of an acrylic elastic material, so it has significantly improved weather resistance and excellent durability and heat resistance. Moreover, the acrylic-polyoxyalkylene composition used as a curing agent is a low-molecular-weight acrylic composition that has an average of about 1 functional group at the end of the molecule and about 1 functional group at any position within the molecule that can react with isocyanate groups. It becomes a mixture of a polymer, a polyoxyalkylene polyol, and a grafted product in which this low molecular weight acrylic copolymer is grafted onto a polyoxyalkylene polyol, and contributes to lowering the modulus of the sealant. Among this mixture, the above-mentioned low molecular weight acrylic copolymer is a copolymer having a structure and performance similar to a telechelic type low molecular weight polymer having functional groups at both ends of the molecule, and has almost both long-chain molecules. The structure has a functional group involved in curing at the end. For this reason, the sealant can have a high molecular weight in linear and network shapes when cured, and has a low modulus. Since the above-mentioned graft body also has a structure in which the above-mentioned low molecular weight acrylic copolymer is grafted onto polyoxyalkylene polyol, the distance between crosslinks becomes long when the sealant is cured, and a sealant with low modulus is obtained. . Furthermore, the acrylic isocyanate component used as the main component also has a structure and performance similar to the telechelic type low molecular weight material, and similarly contributes to lowering the modulus of the sealant. Furthermore, the curing agent of this elastic sealant contains a high viscosity acrylic low molecular weight copolymer, but by mixing low viscosity polyoxyalkylene polyol, the viscosity of the curing agent can be increased without using a solvent. Since it is possible to lower the elastic sealant, workability during construction can be improved without deteriorating the properties of the elastic sealant, and furthermore, it does not cause eye loss after construction. As the main ingredient in the elastic sealant of the present invention, a polyoxyalkylene isocyanate component or an acrylic isocyanate component may be used alone, or both may be used as a mixture in any proportion. According to this, the ratio of the polyoxyalkylene component and acrylic component in the sealant can be varied over a wide range depending on the purpose, and the base polyoxyalkylene isocyanate component or acrylic isocyanate component and curing agent can be obtained. The sealant can have various properties depending on the combination of the polyoxyalkylene polyol and the acrylic monomer mixture used for this purpose. The polyoxyalkylene isocyanate component used as the main ingredient is a polyoxyalkylene polyol obtained by polymerizing a polyhydric alcohol such as ethylene glycol, propylene glycol, or glycerin and an alkylene oxide such as ethylene oxide or propylene oxide, specifically polyethylene glycol. , polypropylene glycol, polyoxypropylene polyol, or polyoxyethylene-polyoxypropylene polyol, by reacting at least one polyoxyalkylene polyol with an organic diisocyanate.
The average molecular weight of the above polyoxyalkylene polyol is preferably 300 to 6,000. The organic diisocyanate used to introduce an isocyanate group into at least the molecular terminal of the above polyoxyalkylene polyol is not particularly limited, and specifically includes 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, Examples include 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, and hexamethylene diisocyanate. In addition, as the acrylic isocyanate component used as the main component, in the presence of a polymerization initiator having a functional group capable of reacting with an isocyanate group or a chain transfer agent having a functional group capable of reacting with an isocyanate group, A) reacting with the isocyanate group. B) 100 to 50% by weight of a (meth)acrylic acid alkyl ester whose alkyl group has 2 to 14 carbon atoms, and other materials that can be copolymerized with this. An average of about 1 functional group at the end of the molecule that can react with the isocyanate group obtained by copolymerizing an acrylic monomer mixture with a main monomer consisting of 0 to 50% by weight of unsaturated monomers. And, it is obtained by further reacting an acrylic low molecular weight copolymer having an average of about one copolymer at any arbitrary position within the molecule with an organic diisocyanate. Polymerization initiators having a functional group capable of reacting with the above-mentioned isocyanate groups include polymerization initiators having a carboxyl group and a hydroxyl group, specifically azobiscyanovaleric acid, oxalic acid peroxide, and azobiscyanopentanol. Examples include. Chain transfer agents having a functional group that can react with an isocyanate group include those having a carboxyl group, a hydroxyl group, or an amino group, and specifically include thioglycolic acid, 2-mercaptoacetic acid,
Examples include 2-mercaptoethanol and 2-aminoethanethiol. During copolymerization, the above polymerization initiator and the above chain transfer agent may be used together, or either one of them may be used. The amount of these used is such that on average about one functional group capable of reacting with the isocyanate group derived from the above polymerization initiator or chain transfer agent is introduced into the molecular terminal of the low molecular weight acrylic copolymer, and this copolymer is In order to prevent the average molecular weight from being too low or too high, the amount is preferably in the range of 0.3 to 20 parts by weight per 100 parts by weight of B monomer. Next, the A monomer mentioned above is a carboxyl group,
It is an unsaturated monomer having a hydroxyl group, and specific examples include acrylic acid, methacrylic acid, maleic acid, 2-hydroxyethyl acrylate, and 2-hydroxyethyl methacrylate. The B monomer mentioned above 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,
- 100 to 50% by weight of one or more alkyl esters such as ethylhexyl and other monomers copolymerizable with these, specifically vinyl acetate, vinyl propionate, acrylonitrile,
It contains 0 to 50% by weight of at least one unsaturated monomer selected from methyl methacrylate, styrene, and acrylamide. It should be noted that if the amount of the other copolymerizable unsaturated monomer exceeds 50% by weight, it is not preferable because weather resistance decreases. The usage ratio of A monomer and B monomer is determined by adjusting the degree of polymerization and polymerization ratio within the range where the usage amount of A monomer is 1/10 to 1/500 mol of the usage amount of B monomer. Taking this into consideration, it is determined that on average about one functional group capable of reacting with the isocyanate group derived from the A monomer is introduced at any position within the molecule of the acrylic low molecular weight copolymer. The above-mentioned low molecular weight acrylic copolymer is produced by copolymerizing a predetermined amount of monomer A and monomer B in the presence of a predetermined amount of a polymerization initiator or a chain transfer agent according to a conventional method. can get. Polymerization is radical polymerization, such as benzoyl peroxide, α・
Conventional polymerization initiators such as α'-azobisisobutyronitrile are used, but these conventional initiators are not necessarily required when the specific polymerization initiators described above are used. In this copolymerization, it is preferable to carry out bulk polymerization without using a solvent, and if unreacted monomers remain, it will cause odor during sealant application and eye discoloration after application, so unreacted monomers It is preferable to adjust the polymerization conditions such as temperature and time so that no particles remain. An acrylic isocyanate component is obtained by reacting the thus obtained low molecular weight acrylic copolymer with an organic diisocyanate. As the above-mentioned organic diisocyanate, those exemplified for the polyoxyalkylene isocyanate component can be similarly used. The average molecular weight of this acrylic isocyanate component is not particularly limited as long as it is liquid, but it is preferably 1500 to 1,500.
It is better to use 6000. The acrylic-polyoxyalkylene composition as a curing agent in the elastic sealant of the present invention is composed of acrylic monomers of monomer a and monomer b in the presence of 5 to 30 parts by weight of polyoxyalkylene polyol. It is obtained by copolymerizing 100 parts by weight of the mixture using a polymerization initiator or chain transfer agent having a functional group capable of reacting with an isocyanate group. The polyoxyalkylene polyol used here is one of the same polyoxyalkylene polyols as exemplified for the polyoxyalkylene isocyanate component of the main ingredient, but has an average molecular weight of
1000 to 6000 is preferably used. If the molecular weight of this polyol is lower than 1000, the hardness of the sealant will increase, which is not preferable. In addition, the a monomer, b monomer, and the polymerization initiator or chain transfer agent react with the A monomer, B monomer, and isocyanate group used to obtain the acrylic isocyanate component in the main ingredient, respectively. A polymerization initiator having a functional group capable of reacting with an isocyanate group or a chain transfer agent having a functional group capable of reacting with an isocyanate group are used in the same proportions. This copolymerization can be carried out in the presence of a polyoxyalkylene polyol in the same manner as the copolymerization for obtaining a low molecular weight acrylic copolymer in the acrylic isocyanate component of the main ingredient. The acrylic-polyoxyalkylene composition obtained in this way is a low molecular weight acrylic composition having an average of about 1 functional group at the end of the molecule and about 1 functional group at any position within the molecule that can react with an isocyanate group. It is a mixture of a polymer, a polyoxyalkylene polyol, and a grafted product in which the above-mentioned low molecular weight acrylic copolymer is grafted onto a polyoxyalkylene polyol, and contributes to lowering the modulus of the sealant. Moreover, since polyoxyalkylene polyol is mixed, the viscosity of the curing agent blend system prepared by blending this curing agent with various additives described later does not become too high, and workability is good. The ratio of the polyoxyalkylene component to the acrylic component in the elastic sealant of this invention can be varied over a wide range depending on the purpose, but usually the acrylic component is 15 to 15% of the total amount of the base agent and curing agent.
Preferably, the content is 95% by weight. If the acrylic component in the sealant is too small, the properties of the sealant as an acrylic elastic body will be low and the weather resistance will be poor, which is not preferable. Further, if the amount is too large, the viscosity of the sealant increases and workability decreases, which is not preferable. In addition, the blending ratio of the base resin and curing agent in this invention is usually such that the amount of functional groups capable of reacting with isocyanate groups in the curing agent is 0.7 to 1.1 equivalents per 1 equivalent of isocyanate groups in the base resin. preferable. The elastic sealant of the present invention can contain fillers and catalysts required for general sealants. Further, pigments, anti-aging agents, anti-mold agents, antioxidants, ultraviolet absorbers, ozone deterioration inhibitors, thixotropic agents, etc. can be added as necessary. The above fillers improve the strength of the cured sealant, such as calcium carbonate,
Examples include silica powder, talc, glass powder, and titanium oxide. The amount of these fillers added is
The amount is preferably 30 to 200 parts by weight per 100 parts by weight; 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, which is not preferable. Further, as the catalyst, organic metal compounds such as dibutyltin dilaurate, monobutyltin oxide, and dioctyltin dilaurate, and amine derivatives such as triethylenediamine, triethylenetetramine, and diaminodiphenylmethane can be used. The amount of these additives is preferably 0.01 to 5 parts by weight per 100 parts by weight of the curing agent. The elastic sealant of the present invention configured as described above has the advantage that it has good workability during construction and does not cause eye loss after construction. In addition, the sealant after curing has the characteristics of an acrylic elastic material, so it has excellent weather resistance, durability, and heat resistance, and has low modulus and high elongation, easily following changes in joint width, and over time. No cracks occur even after a long time. Next, examples of this invention will be described. In the following, "part" means part by weight, "%" means weight %, and "molecular weight" means average molecular weight, respectively. Example 1 An acrylic blended composition was prepared consisting of 100 parts of n-butyl acrylate, 10 parts of acrylonitrile, 1.0 part of acrylic acid, and 1.6 parts of thioglycolic acid. 30% of this blended composition and 10 parts of polypropylene glycol having a molecular weight of 3000 were placed in a 200 c.c. 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 nitrogen for about 60 minutes, when 0.1 part of α·α'-azobisisobutyronitrile was added, heat generation immediately started. After the heat generation became somewhat gradual, 0.2 part of α·α'-azobisisobutyronitrile was added to the remainder of the above-mentioned composition and was gradually added into the flask using a dropping funnel over a period of about 3 hours. The point at which no heat generation was observed thereafter was defined as the end point of polymerization. The acrylic-polyoxyalkylene composition thus obtained had a viscosity of 250 poise (30° C., 2 rpm) as measured by a B-type rotational viscometer. 100 parts of this composition, 100 parts of calcium carbonate, 23 parts of titanium dioxide, 1.6 parts of Disparon 3600N (polyether ester type surfactant manufactured by Kusumoto Kasei Co., Ltd.),
0.5 part of dibutyltin dilaurate was blended, premixed using a kneader, and further kneaded using three rolls to obtain a curing agent blended system for the elastic sealant of the present invention. It was obtained by reacting 2,4-tolylene diisocyanate as an organic diisocyanate with a polyoxyalkylene polyol consisting of a mixture of 100 parts of polypropylene glycol with a molecular weight of 3000 and 30 parts of polyoxypropylene triol with a molecular weight of 3000 as the main ingredient. Polyoxyalkylene isocyanate component (isocyanate group content 2.85%)
The elastic sealant of the present invention was prepared by blending 100 parts of a curing agent compounding system with 30 parts of the base resin so that the curing agent was about 150 parts per 100 parts of the base resin. Example 2 Conducted using an acrylic compound composition consisting of 95 parts of n-butyl acrylate, 5 parts of styrene, 3 parts of 2-hydroxyethyl acrylate, and 2 parts of 2-mercaptoethanol, and 20 parts of polypropylene glycol with a molecular weight of 4000. An acrylic-polyoxyalkylene composition was obtained in the same manner as in Example 1. This composition has a viscosity of 70 poise (30°C,
2 rpm). 100 parts of this composition, 120 parts of calcium carbonate, 16 parts of titanium dioxide, 2.4 parts of Disparon 3600N (mentioned above)
1 part, 0.2 part of triethylenetetramine, and 0.2 part of carbon black were thoroughly kneaded using a kneader and three rolls to obtain a curing agent blend system according to the present invention. An acrylic isocyanate component used as a main ingredient was obtained as follows. That is, an acrylic low molecular weight copolymer was obtained in the same manner as in Example 1 using only the above acrylic blended composition. 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 4200 measured by vapor pressure osmosis, and a number of hydroxyl groups per molecule.
It was 2.08. 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,
The reaction was carried out at 80° C. for 5 hours to obtain an acrylic isocyanate component (isocyanate group content: 2.05%) into which isocyanate groups were introduced. The elastic sealant of the present invention was prepared by adding 100 parts of a curing agent compound to 50 parts of this acrylic isocyanate component so that the curing agent was about 80 parts based on 100 parts of the main agent. Example 3 Same as Example 1 using an acrylic compound composition consisting of 100 parts of 2-ethylhexyl acrylate, 15 parts of acrylonitrile, 1.5 parts of acrylic acid, and 1.8 parts of 2-mercaptoacetic acid and 15 parts of polypropylene glycol having a molecular weight of 1000. An acrylic-polyoxyalkylene composition was obtained. However, azobiscyanovaleric acid was used as a polymerization initiator instead of α·α'-azobisisobutyronitrile.
This composition has a viscosity of 100 as measured by a B-type rotational viscometer.
It was poise (30℃, 2rpm). 100 parts of this composition, 110 parts of calcium carbonate, 25 parts of titanium dioxide, 1.7 parts of Disparon 3600N (mentioned above)
1 part, dibutyltin dilaurate 0.5 parts,
The mixture was sufficiently kneaded using a kneader and three rolls to form a curing agent compounded system. Using the same acrylic isocyanate component as the base component in Example 2 as the base component, 60 parts of the acrylic isocyanate component was blended with 100 parts of the curing agent so that the curing agent was approximately 70 parts per 100 parts of the base component. This invention was made into an elastic sealant. Example 4 50 parts of n-butyl acrylate, ethyl acrylate
50 parts, 2-hydroxyethyl acrylate 1 part, 2
- An acrylic-polyoxyalkylene composition was obtained in the same manner as in Example 1 using an acrylic compound composition consisting of 2 parts of mercaptoethylamine and 30 parts of polypropylene glycol having a molecular weight of 4000. This composition had a viscosity of 300 poise (30° C., 2 rpm) using a B-type rotational viscometer. 100 parts of this composition, 100 parts of calcium carbonate, 15 parts of titanium dioxide, 2 parts of Disparon 3600N (mentioned above),
0.1 part of dibutyltin dilaurate and 0.1 part of carbon black were blended and thoroughly kneaded using a kneader and three rolls to obtain a curing agent blend system. Using the same polyoxyalkylene isocyanate component as the base material of Example 1 as the base material,
Add 35 parts of this polyoxyalkylene isocyanate component so that the curing agent is about 130 parts to 100 parts.
The elastic sealant of the present invention was prepared by adding 100 parts of a curing agent compounding system to 1 part of the elastic sealant of the present invention. Example 5 90 parts of n-butyl acrylate, 10 parts of vinyl acetate,
An acrylic-polyoxyalkylene composition was prepared in the same manner as in Example 1 using an acrylic compound composition consisting of 3 parts of 2-hydroxyethyl acrylate and 2 parts of 2-mercaptoethanol and 10 parts of polyethylene glycol having a molecular weight of 1000. Obtained. This composition has a viscosity of 85 poise (30°C,
2 rpm). 100 parts of this composition, 120 parts of calcium carbonate, 16 parts of titanium dioxide, 1.5 parts of Disparon 3600N (mentioned above)
1 part, 0.2 part of triethylenetetramine, and 0.2 part of carbon black were thoroughly kneaded using a kneader and three rolls to obtain a curing agent blend system according to the present invention. An acrylic isocyanate component used as a main ingredient was obtained as follows. That is, an acrylic low molecular weight copolymer was obtained in the same manner as in Example 1 using only the above acrylic blended composition. This copolymer has a polymerization rate of 100%, a viscosity of 90 poise measured by a B-type rotational viscometer (30°C, 2 rpm), a molecular weight of 3800 measured by vapor pressure osmosis, and a number of hydroxyl groups per molecule.
It was 2.01. After dehydrating 100 parts of this acrylic low molecular weight copolymer, 10 parts of xylylene diisocyanate and 0.003 parts of dibutyltin dilaurate were added, and the mixture was reacted at 80°C for 5 hours. content 1.99%). The elastic sealant of the present invention was prepared by adding 100 parts of a curing agent compound to 50 parts of this acrylic isocyanate component so that the curing agent was about 80 parts based on 100 parts of the main agent. Example 6 An acrylic compound composition consisting of 100 parts of 2-ethylhexyl acrylate, 20 parts of vinyl propionate, 1.5 parts of acrylic acid, and 1.8 parts of 2-mercaptoacetic acid and polyethylene propylene glycol with a molecular weight of 1450 (ethylene oxide accounted for in all molecules) The weight of is 20
%) to obtain an acrylic-polyoxyalkylene composition in the same manner as in Example 1. However, azobiscyanovaleric acid was used as a polymerization initiator instead of α·α'-azobisisobutyronitrile. This composition had a viscosity of 160 poise (30° C., 2 rpm) using a B-type rotational viscometer. 100 parts of this composition, 80 parts of calcium carbonate, 15 parts of titanium dioxide, 1.5 parts of Disparon 3600N (mentioned above)
1 part, dibutyltin dilaurate 0.4 parts,
The mixture was sufficiently kneaded using a kneader and three rolls to form a curing agent compounded system. As the main ingredient, a polyoxyalkylene isocyanate component (isocyanate group content: 7.4%) having an isocyanate group at the molecular end obtained by reacting polyethylene glycol with a molecular weight of 800 with hexamethylene diisocyanate as an organic diisocyanate was used, and 100 parts of the main ingredient was used. The elastic sealant of the present invention was prepared by blending 100 parts of a curing agent compounding system with 11 parts of this main ingredient so that the curing agent amounted to about 440 parts. Example 7 50 parts of n-butyl acrylate, ethyl acrylate
50 parts, 5 parts of acrylamide, 10 parts of methyl methacrylate, 1 part of 2-hydroxyethyl acrylate,
An acrylic-polyoxyalkylene composition was obtained in the same manner as in Example 1 using an acrylic compound composition consisting of 2 parts of 2-mercaptoethylamine and 30 parts of polypropylene glycol having a molecular weight of 3000. This composition has a viscosity measured by a B-type rotational viscometer.
It was 280 poise (30°C, 2 rpm). 100 parts of this composition, 100 parts of calcium carbonate, 15 parts of titanium dioxide, 2 parts of Disparon 3600N (mentioned above),
0.1 part of dibutyltin dilaurate and 0.1 part of carbon black were blended and thoroughly kneaded using a kneader and three rolls to obtain a curing agent blended system. The main ingredient is a polyoxyalkylene type having an isocyanate group at the end of the molecule, obtained by reacting polyethylene propylene glycol with a molecular weight of 1450 (the weight of ethylene oxide in the entire molecule is 20%) with xylylene diisocyanate as an organic diisocyanate. The elastic sealant of this invention is made by using an isocyanate component (isocyanate group content 5.2%) and blending 100 parts of the curing agent compounding system with 12 parts of the base resin so that the curing agent is about 370 parts per 100 parts of the base resin. did. Comparative Example 1 Instead of the acrylic-polyoxyalkylene composition in the curing agent blending system of Example 1, molecular weight
The procedure was the same as in Example 1, except that the same amount of polypropylene glycol 3000 was used (but the main ingredient
So that the above curing agent is 70 parts per 100 parts,
An elastic sealant for comparison was prepared by blending 100 parts of a curing agent compound into 60 parts of the base agent. Comparative Example 2 When producing the acrylic-polyoxyalkylene composition of Example 1, an acrylic blended composition consisting of 100 parts of n-butyl acrylate, 10 parts of acrylonitrile, and 2.2 parts of lauryl mercaptan was used as the acrylic blended composition. An acrylic-polyoxyalkylene composition was prepared in the same manner as in Example 1, except that a comparative elastic sealant was prepared with the same composition as in Example 1. When properties were evaluated based on JIS-A-5758 for the elastic sealants obtained in Examples 1 to 7 and Comparative Examples 1 and 2, Examples 1 to 7
The sealant of Comparative Example 1 had a slump of 0 mm and was free from staining, but the sealant of Comparative Example 2 had a slump of 10 mm and showed some staining. Furthermore, the extrudability and tensile adhesion properties were as shown in the following table.

【table】

[Table] Also, the above Examples 1 to 7 and Comparative Examples 1 and 2
When the cured products of the elastic sealants were subjected to an outdoor exposure test (for 6 months), no surface cracks occurred in any of the sealants of Examples 1 to 7. However, the sealant of Comparative Example 1 had significant surface cracks, and the sealant of Comparative Example 2 had some cracks.

Claims (1)

[Claims] 1 Obtained by reacting an organic diisocyanate with at least one polyoxyalkylene polyol selected from polyethylene glycol, polypropylene glycol, polyoxypropylene polyol, or polyoxyethylene-polyoxypropylene polyol having an average molecular weight of 300 to 6000. A polyoxyalkylene isocyanate component having an isocyanate group at the end of the molecule or a low molecular weight acrylic component having an average of about one isocyanate group at the end of the molecule and an average of about one at any position within the molecule with an average molecular weight of 1,500 to 6,000. At least one polyoxyalkylene polyol selected from polyethylene glycol, polypropylene glycol, polyoxypropylene polyol, or polyoxyethylene-polyoxypropylene polyol, which has a polymer isocyanate component as a main ingredient and has an average molecular weight of 1000 to 6000.
In the presence of 30 parts by weight, a) a functional unsaturated monomer having one carboxyl group or hydroxyl group in the molecule as a functional group capable of reacting with an isocyanate group, and b) an alkyl group having 2 to 14 carbon atoms. (meth)acrylic acid alkyl ester of 100-50% by weight
and a main monomer consisting of 0 to 50% by weight of at least one unsaturated monomer selected from vinyl acetate, vinyl propionate, acrylonitrile, methyl methacrylate, styrene or acrylamide, the former 100 parts by weight of an acrylic monomer mixture in which the amount of the a monomer used is in the range of 1/10 to 1/500 mole of the amount of the latter b monomer,
A polymerization initiator having a carboxyl group or a hydroxyl group as a functional group capable of reacting with an isocyanate group in a proportion of 0.3 to 20 parts by weight per 100 parts by weight of the above b monomer, or a carboxyl group as the same functional group,
An elastic sealant whose curing agent is an acrylic-polyoxyalkylene composition copolymerized with a chain transfer agent having a hydroxyl group or an amino group.