JPH07197010A - Two-component acryl-urethane sealant composition - Google Patents

Abstract

PURPOSE:To obtain the subject compsn. which is excellent in weatherability and durability and can form an elastic sealant with a low surface tackiness by combining a specific isocyanate as the major component and a specific low-molecular acrylic (co)polymer as the curative. CONSTITUTION:This sealant compsn. comprises an NCO-terminated polyoxyalkylene polyisocyanate (A) as the major component and a low-molecular acrylic (co)polymer (B), as the curative, which is obtd. by reacting a monomer mixture comprising an unsatd. monomer (a) having an OH or NH2 group, a (meth)acrylic ester (b), and an unsatd. monomer (c) (e.g. vinyl acetate or acrylonitrile) and/or an unsatd. monomer (d) having a COOH group in the presence of a polymn. initiator or a chain transfer agent. In the monomer mixture, the wt. ratio of monomer (b) to monomer (c) and/or monomer (d) is (100:0)-(50:50), and the molar ratio of monomer (a) to the sum of monomer (b), (c), and (d) is (1:10)-(1:500).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an elastic sealant having less tack on the surface of the sealant, excellent weather resistance, durability and adhesion to the finish coating material, and less contamination to the finish coating material.

[0002]

2. Description of the Related Art Modified silicone type, polysulfide type, silicone type, acrylic urethane type, and urethane type are known as elastic sealants, but they still have many problems. For example, in modified silicones, tackiness appears on the sealant surface due to craters on the sealant surface and curing conditions. There are things that make things dirty. Further, the polysulfide-based material has a point that the finish coating material on the surface is soiled, a crater appears on the surface of the sealant, a modulus is increased by heat, and elongation is significantly reduced. The silicon-based material has problems that the finish coating material is difficult to adhere to the surface, dust is likely to adhere to the surface, and a crater phenomenon occurs. Urethane type has heat resistance
There are disadvantages such as insufficient weather resistance, easy tacking and stains on the surface, and risk of foaming when the temperature and humidity during construction are high.

[0003]

On the other hand, conventionally, the acrylic urethane type sealant is mainly composed of polyoxyalkylene type isocyanate or acrylic type isocyanate and has a functional group capable of reacting with an isocyanate group at an average of about 1 at the molecular end. Elastic sealant composed of an acrylic low molecular weight (co)polymer having an average number of 1 at any position in the molecule, a polyoxyalkylene polyol, and a curing agent containing as a main component a mixture with a graft product of both. However, it is proposed that they have excellent weather resistance, durability and heat resistance. A representative example of this type is Japanese Examined Patent Publication No. 2-22781.

However, these compositions have the drawback that they tend to be contaminated by dust and the like due to the tackiness of the sealant surface, and when they are used for exposed joints despite their excellent weather resistance and durability. The fact is that the range of use is limited and the usage is limited.

It is an object of the present invention to provide a two-pack type acrylic urethane sealing agent composition capable of producing an elastic sealant with less tack on the sealant surface while maintaining the excellent performance of the acrylic urethane type.

[0006]

[However, in the above (b), (c) and (d), at least one of (c) and (d) is 0 to 50% by weight with respect to 100 to 50% by weight of (b), and (a) The amount used is within the range of 1/10 to 1/500 mol of the total amount used of (b) and at least one of (c) and (d). The amount of (e) used is 0.1 to 30 parts by weight per 100 parts by weight of the monomer mixture consisting of (a), (b), (c) and/or (d). ]

[0007]

The elastic sealant composed of the two-pack type acrylic urethane sealing agent composition of the present invention has both the rubber elasticity as a urethane type and the weather resistance and heat resistance as an acrylic type, and the acrylic low molecular weight in the curing agent. By adjusting the number of functional groups that can react with the isocyanate groups of the (co)polymer and the average distance between crosslinks, the sealant has low hardness, low modulus, and high elongation, and is required for architectural sealants. The characteristics are satisfied, and the tack is improved.

When the functional unsaturated monomer having one carboxyl group, epoxy group or hydrolyzable group (d) in the molecule is used as the curing agent together with other components, for example, the above-mentioned functional When a silane coupling agent having a hydrolyzable group at the terminal of the molecule is used as the unsaturated monomer, in the molecular structure of the acrylic low molecular weight (co)polymer as the curing agent, it may be appropriately separated in the middle of the molecular chain. The structure has a structure in which a hydrolyzable group is added to the pendant-bonded hydroxyl group or amino group. When an acrylic unsaturated monomer such as vinylsilane having a hydrolyzable group at the molecular end is used, the acrylic low molecular weight (co)polymer as a curing agent becomes a copolymer with the vinylsilane. By doing so, only the tack on the surface can be further improved without deteriorating the properties of the elastic sealant.

Next, the present invention will be described in detail.

The two-component type acrylic urethane sealing agent composition of the present invention comprises the above-mentioned main agent (A) and a curing agent (B).

The main agent (A) is a polyoxyalkylene isocyanate having an isocyanate group at the molecular end by reacting a polyoxyalkylene polyol having an average molecular weight of 300 to 6000 with an organic diisocyanate as described above. The polyoxyalkylene isocyanate component is obtained by polymerizing a polyhydric alcohol and an alkylene oxide, and the number average molecular weight of this polyoxyalkylene polyol is preferably 300 to 6000 in terms of effects.

Examples of the polyhydric alcohol which is a raw material for the polyoxyalkylene incyanate component include ethylene glycol, propylene glycol, glycerin and trimethylolpropane. Preferred are diols such as ethylene glycol and propylene glycol, and triols such as glycerin.

Also, as the alkylene oxide which is a raw material of the above, propylene oxide, ethylene oxide, butylene oxide and the like can be mentioned, and these can be used alone or in admixture of two or more kinds.

Specific examples of the organic diisocyanate to be reacted with the polyoxyalkylene polyol obtained by the above method include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, Examples include xylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and bis(isocyanatomethyl)cyclohexane. Preferably, 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate are used, but when non-yellowing diisocyanate such as hexamethylene diisocyanate and isophorone diisocyanate is used, the heat resistance of the resulting elastic sealant,
It is preferable to use these because the weather resistance is further improved.

Next, the curing agent will be described.

The curing agent used in the present invention is the following (a)
It is an acrylic low molecular weight (co)polymer obtained by reacting a monomer mixture composed of (b), (c) and at least one of (d) in the presence of (e) below. (A) A functional unsaturated monomer having one hydroxyl group or amino group in the molecule as a functional group capable of reacting with an isocyanate group. (B) (Meth)acrylic acid alkyl ester. (C) At least one unsaturated monomer selected from the group consisting of vinyl acetate, vinyl propionate, acrylonitrile, styrene and acrylamide. (D) A functional unsaturated monomer having one carboxyl group, epoxy group or hydrolyzable group in the molecule. (E) A polymerization initiator or a chain transfer agent.

Examples of the functional unsaturated monomer having a hydroxyl group or an amino group as a functional group capable of reacting with an isocyanate group in the component (a) include 2-hydroxyethyl methacrylate and acrylic acid. 2-hydroxyethyl, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, 3-chloro-2-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl acrylate, allyl alcohol, methylolation Unsaturated hydroxyl group-containing monomers such as acrylamide and methylolated methacrylamide, methacrylic acid-2,
An amino group-containing unsaturated monomer such as 2,6,6-tetramethylpiperidine can be used. In this case, the component raw materials may be used alone or in combination. When used in combination, a preferred combination is 2-hydroxyethyl methacrylate and-3-chloro-2-hydroxypropyl methacrylate.

Examples of the component (b) include acrylic acid or methacrylic acid having 2 to 14 carbon atoms such as ethyl,
One or more of alkyl esters such as n-butyl, isobutyl, 1-ethylpropyl, 2-methylpentyl, 2-ethylbutyl and 2-ethylhexyl can be used. In this case, these component raw materials may be used alone or in combination. When used in combination, a preferable combination is n-butyl acrylate and acrylic acid -2.
-Ethylhexyl.

Examples of the component (c) include vinyl acetate, vinyl propionate, acrylonitrile, styrene and acrylamide, which may be used alone or in combination. When used in combination, a preferable combination is vinyl acetate and acrylonitrile.

The component (d) is a functional unsaturated monomer having one carboxyl group, epoxy group or hydrolyzable group in the molecule.

Examples of this type of unsaturated monomer include carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid and itaconic acid, or glycidyl acrylate, glycidyl methacrylate, glycidyl vinyl sulfonate and allyl. Epoxy group-containing unsaturated monomers such as glycidyl ether, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane and other hydrolyzable group-containing unsaturated monomers A mer can be used. The component (d) is used instead of the component (c) or together with the component (c), and serves as an additional component as described above. in this case,
When used in combination with the component (c), the mutual ratio is 100% by weight of the component (c) and 0 to 500% by weight of the component (d).
It is preferable that the ratio is In particular (c)
A suitable combination when the component and the component (d) are combined is acrylonitrile and acrylic acid.

The polymerization initiator or chain transfer agent as the component (e) serves as a polymerization catalyst when radically polymerizing the above (a) to (d), and for example, a peroxide such as benzoyl peroxide, Azonitrile compounds such as α,α′-azobisisobutyronitrile are used. As the chain transfer agent, thiols such as butanethiol, 2-mercaptoethanol, n-dodecylmercaptan, etc. are used.

Next, the use ratio of each of the component raw materials (a) to (e) in the curing agent of the component (B) will be described.

(B) which constitutes the above curing agent (B),
The mutual use ratios of the components (c) and (d) are as follows. That is, at least one of (c) and (d) is 0 to 50 with respect to 100 to 50% by weight of (b).
Set to% by weight. If at least one of (c) and (d) exceeds 50% by weight, the weather resistance becomes low, which is not preferable. The amount of (a) used is 1 of the total amount of (b) and at least one of (c) and (d).
It is set within a range of 1/0 to 1/500 mol. As a result, a plurality of hydroxyl groups or amino groups (usually 3 to 15) are pendantly bonded at predetermined positions in the molecular chain of the acrylic low molecular weight (co)polymer that is the curing agent (B). Become.

In addition, the amount of the component (e) such as the polymerization initiator to be used is 100 in terms of the effect, and the total amount of the components (a) to (d) is 100.
It is set within the range of 0.1 to 30 parts by weight with respect to parts by weight.

The molecular weight of the acrylic low molecular weight (co)polymer, which is the curing agent (B) obtained by using the raw materials (a) to (e), is not particularly limited as long as it is liquid.
It is preferable to use one having a number average molecular weight of 1500 or more. From the viewpoint of workability of the sealant obtained by using the two-component acrylic urethane sealing agent composition of the present invention and elasticity of the cured sealant, it is more preferable to use one having a number average molecular weight of 2000 to 9000. When the number average molecular weight exceeds 9000, the viscosity becomes high and the fluidity becomes insufficient, so that there is a problem in use. On the other hand, when the number average molecular weight is less than 1500, the obtained elastic sealant may have tackiness and the like.

The acrylic low molecular weight (co)polymer which serves as the above-mentioned curing agent can be obtained by copolymerizing the above-mentioned components (a) to (e) according to a conventional method. The polymerization is radical polymerization.

The above-mentioned copolymer is usually obtained by solution polymerization in a non-aqueous solution. However, in addition to solution polymerization, for example, a polymer obtained by bulk polymerization, suspension polymerization, emulsion polymerization or the like is used as a non-aqueous solution. Things can also be used.

The solvent used for solution polymerization, or the solvent used when the polymer obtained by another polymerization method is made into a non-aqueous solution, is usually aromatic hydrocarbons, ketones, alcohols (preferably isopropanol). ), esters, ethers, etc., or a mixture of two or more thereof can be used.

The above-mentioned curing agent (B) may contain a filler and a catalyst necessary for the elastic sealant.
Further, if necessary, a plasticizer, an antioxidant, an antioxidant, an ultraviolet absorber, a dehydrating agent, a thixotropic agent, etc. can be added.

As the filler, for example, fumed silica,
Reinforcing fillers such as precipitated silica, heavy calcium carbonate, light calcium carbonate, non-reinforcing fillers such as microballoons and the like can be mentioned. The addition amount of these fillers is preferably 30 to 70 parts by weight with respect to 100 parts by weight of the curing agent. If the addition amount is too small, it is difficult to obtain a predetermined strength, and if the addition amount is too large, the elongation of the cured product is poor. Is not preferable.

Examples of the catalyst include lead-based catalysts such as lead octylate and lead naphthenate, tin-based catalysts such as dibutyltin dilaurate and tin octylate, and amine-based derivatives such as triethylenediamine and diaminodiphenylmethane. Etc. can be used. The addition amount of these is preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the curing agent.

The two-pack type acrylic urethane sealing agent composition of the present invention is obtained by blending the above-mentioned main agent (A) and curing agent (B). In this case, the mixing ratio of the main agent (A) and the curing agent (B) is such that the functional group capable of reacting with the isocyanate group in the curing agent (B) is 0 with respect to 1 equivalent of the isocyanate group in the main agent (A). It is preferable to set it to be 0.7 to 1.5 equivalents. The functional group is 0.
This is because if it is less than 7 equivalents, there is a risk of foaming, and if it exceeds 1.5 equivalents, the tack on the surface becomes remarkable.

The molecular structure of the acrylic low molecular weight (co)polymer (which constitutes the elastic sealant) is (a)
Taking the case of (1) and (b) as an example,
As shown in the following formula (1), a plurality of hydroxyl groups are pendantly bonded to the main chain at predetermined intervals.
This serves as the main component, and as the subcomponent, the compound of the formula (2) having a hydroxyl group bonded to the terminal is generated. In this case, the production ratio of the subcomponent is about 2 to 10%.

[0035]

[Chemical 1]

[0036]

[Chemical 2]

On the other hand, the acrylic low molecular weight (co)polymer which constitutes the elastic sealant described in Japanese Patent Publication No. 2-22781 is represented schematically by the following formula (3). The molecular structure is such that about 1 hydroxyl group on average at the end of the molecular chain and about 1 hydroxyl group on average at any position in the molecule are bonded.

[0038]

[Chemical 3]

Due to such a difference in structure, the sealant obtained by the two-component type acrylic urethane sealing agent composition of the present invention has excellent weather resistance and heat resistance as compared with those described in the above publications. Moreover, the tack etc. will be improved.

[0040]

As described above, the two-pack type acrylic urethane sealing agent composition of the present invention is composed of the main agent (A) and the curing agent (B), and is thus obtained. The elastic sealant has both rubber elasticity as a urethane type and weather resistance and heat resistance as an acrylic type, and corrects the position and number of functional groups such as hydroxyl groups capable of reacting with isocyanate groups in the curing agent. Therefore, tack on the surface of the sealant is improved, and adhesion of dust or the like is less likely to occur.

Next, examples will be described together with comparative examples. In the following, “part” means “part by weight”.

[0042]

Example 1 [Preparation of curing agent] An acrylic compound composition comprising 170 parts of n-butyl acrylate, 4 parts of 2-hydroxyethyl acrylate, 30 parts of isopropyl alcohol and 2 parts of n-dodecyl mercaptan was prepared. did.

This compounded composition was placed in a 200 cc four-necked flask, the contents of the flask were heated to 80° C. while stirring, and the inside of the flask was replaced with nitrogen, and α,α′-azobisisobutyronitrile was added. 5 parts were added. As a result, an exothermic reaction immediately started and the internal temperature rose. When the amount of reflux became low, 0.5 part of α,α′-azobisisobutyronitrile was further added and reacted to complete the reaction.
As a result, a resin solution having a nonvolatile content of 85% was obtained.

The solvent of this resin solution was removed under reduced pressure until the content became 5% or less to obtain an acrylic low molecular weight (co)polymer. This composition has a viscosity of 1 by a B-type rotational viscometer.
8,000 poise (25° C., 6 rpm), number average molecular weight of 3000 by GPC, number of hydroxyl groups per molecule of 4.
It was 1.

Next, as shown in the number of parts shown in Table 1, a filler, a catalyst, a plasticizer, etc. were added to this curing agent and kneaded to obtain a curing agent composition used in the present invention.

[Preparation of Main Agent] As the main agent, the molecular weight is 20
Polyoxyalkylene isocyanate component obtained by reacting 2,4-tolylene diisocyanate as an organic diisocyanate with a polyoxyalkylene polyol consisting of a mixture of polypropylene glycol of 00 and polyoxypropylene triol having a molecular weight of 3000 (containing an isocyanate group (Amount 2.0%) was prepared.

Next, the curing agent composition was blended in a ratio of 250 parts with respect to 100 parts of the main component to obtain an elastic sealant according to the present invention.

[0048]

Example 2 [Preparation of curing agent] 160 parts of n-butyl acrylate, 3 parts of 3-hydroxypropyl methacrylate, 10 parts of acrylonitrile, 30 parts of isopropanol, 1 part of lauroyl peroxide, 2 parts of n-dodecyl mercaptan. Was used in the same manner as in Example 1 to obtain an acrylic low molecular weight copolymer. This has a viscosity of 27 with a B-type rotational viscometer.
000 poise (25°C, 6 rpm), number average molecular weight by GPC is 2900, number of hydroxyl groups per molecule is 2.5
Met.

Next, as shown in the number of parts shown in Table 1, a filler, a catalyst, a plasticizer, etc. were added to this copolymer,
The mixture was kneaded to obtain a curing agent composition used in this invention.

[Preparation of Main Agent] As the main agent, the molecular weight is 20
Polyoxyalkylene isocyanate component obtained by reacting 2,4-tolylene diisocyanate as an organic diisocyanate with a polyoxyalkylene polyol composed of a mixture of polypropylene glycol of 00 and polyoxypropylene triol having a molecular weight of 3000 (isocyanate group content 3.0%) was prepared.

Next, 290 parts of the hardener composition was blended with 100 parts of the base material to obtain an elastic sealant according to the present invention.

[0052]

Example 3 [Preparation of Curing Agent] 160 parts of n-butyl acrylate, 2.5 parts of 2-hydroxyethyl acrylate, 1.3 parts of acrylic acid, 30 parts of isopropanol, α,α′-azobis Using 1 part of isobutyronitrile and 2 parts of n-dodecyl mercaptan, an acrylic low molecular weight copolymer was obtained in the same manner as in Example 1. This product had a viscosity of 45200 poises (25° C., 6 rpm) by a B-type rotational viscometer, a number average molecular weight of 3700 by GPC, and a hydroxyl group number of 2.5 per molecule.

100 parts of this acrylic low molecular weight copolymer, 1 part of tris-2,4,6 (dimethylaminomethyl)phenol and 8.8 parts of γ-glycidoxypropyltrimethoxysilane were added to a 400 cc four-necked bottle. Put the contents in a flask, and while stirring, replace the inside of the flask with nitrogen to 100 contents.
The mixture was heated to 0° C. and graft-reacted for about 5 hours.

Thus, an acrylic low molecular weight copolymer having a hydrolyzable group was obtained. This product has a viscosity of 82,000 poise (25° C., 6 rp
m).

Next, as shown in the number of parts shown in Table 1, a filler, a catalyst, a plasticizer, etc. were added to this and kneaded to obtain a curing agent composition used in the present invention.

[Preparation of Main Agent] As the main agent, the molecular weight is 30
Polyoxyalkylene isocyanate component obtained by reacting 2,4-tolylene diisocyanate as an organic diisocyanate with a polyoxyalkylene polyol composed of a mixture of polypropylene glycol of 00 and polyoxypropylene triol having a molecular weight of 3000 (isocyanate group content 2.6%) was prepared.

Next, 290 parts of the hardener composition was mixed with 100 parts of the main agent to obtain an elastic sealant according to the present invention.

[0058]

Example 4 [Preparation of Curing Agent] 2-Ethylhexyl Acrylate 16
0 part, 2-hydroxyethyl acrylate 6 parts, isopropanol 30 parts, lauroyl peroxide 1 part, n
Using 2 parts of dodecyl mercaptan, an acrylic low molecular weight copolymer was obtained in the same manner as in Example 1. This one is B
Viscosity of 12,000 poise (25℃,
6 rpm), number average molecular weight by GPC is 3200, 1
The number of hydroxyl groups per molecule was 5.6.

100 parts of this acrylic low molecular weight copolymer and 1 part of γ-isocyanatopropyltrimethoxysilane
1.5 parts was put into a 400 cc four-necked flask, the contents of the flask were heated to 50° C. while stirring and the inside of the flask was replaced with nitrogen, and an addition reaction was carried out for about 3 hours.

In this way, an acrylic low molecular weight copolymer having a hydrolyzable group was obtained. This product has a viscosity of 24000 poise (25°C, 6 rp
m).

Next, as shown in the number of parts shown in Table 1, a filler, a catalyst, a plasticizer, etc. were added to the mixture and kneaded to obtain a curing agent composition for the elastic sealant of the present invention.

[Preparation of Main Agent] As the main agent, the molecular weight is 30
Polyoxyalkylene isocyanate component obtained by reacting 2,4-tolylene diisocyanate as an organic diisocyanate with a polyoxyalkylene polyol composed of a mixture of polypropylene glycol of 00 and polyoxypropylene triol having a molecular weight of 3000 (isocyanate group content 3.0%) was prepared.

Next, the elastic sealant according to the present invention was obtained by mixing 280 parts of the curing agent composition with 100 parts of the main agent.

[0064]

Example 5 [Preparation of Curing Agent] 2-Ethylhexyl Acrylate 16
0 part, 2-hydroxyethyl acrylate 3 parts, glycidyl methacrylate 1.5 parts, isopropanol 30 parts,
An acrylic low molecular weight copolymer was obtained in the same manner as in Example 1 except that 1 part of lauroyl peroxide and 2 parts of n-dodecyl mercaptan were used. This product has a viscosity of 20,000 poise (25°C, 6 rpm) measured by a B-type rotational viscometer, GP
The number average molecular weight by C was 3000, and the number of hydroxyl groups per molecule was 2.7.

100 parts of this acrylic low molecular weight copolymer, 1 part of tris-2,4,6 (dimethylaminomethyl)phenol and 9 parts of γ-aminopropyltrimethoxysilane were placed in a 400 cc four-necked flask and stirred. While the inside of the flask was being replaced with nitrogen, the content was heated to 100° C. and the addition reaction was performed for about 4 hours.

Thus, an acrylic low molecular weight copolymer having a hydrolyzable group was obtained. This product has a B-type rotational viscometer of 47,000 poise (25°C, 6 rp).
m).

Next, as shown in the number of parts shown in Table 1, a filler, a catalyst, a plasticizer, etc. were added to this copolymer,
The mixture was kneaded to obtain a curing agent composition used in this invention.

[Preparation of Main Agent] As the main agent, the molecular weight is 30
Polyoxyalkylene isocyanate component obtained by reacting 2,4-tolylene diisocyanate as an organic diisocyanate with a polyoxyalkylene polyol composed of a mixture of polypropylene glycol of 00 and polyoxypropylene triol having a molecular weight of 3000 (isocyanate group content 2 .2%) was prepared.

Next, the curing agent composition was compounded at a ratio of 300 parts with respect to 100 parts of the main agent to obtain the elastic sealant according to the present invention.

[0070]

Example 6 [Preparation of Curing Agent] 2-Ethylhexyl Acrylate 16
0 parts, 2-hydroxyethyl acrylate 3 parts, γ-methacryloxypropyltrimethoxysilane 1 part, isopropanol 30 parts, laurilopoxide 1 part, n-
An acrylic low molecular weight copolymer was obtained in the same manner as in Example 1 except that 2 parts of dodecyl mercaptan was used. This one is B
Viscosity measured with a rotary viscometer of 30,000 poise (25°C,
6 rpm), number average molecular weight by GPC is 2700, 1
The number of hydroxyl groups per molecule was 2.6.

Next, as shown in the number of parts shown in Table 1, a filler, a catalyst, a plasticizer and the like were added to this composition and kneaded to obtain a curing agent composition used in the present invention.

[Preparation of Main Agent] The main agent has a molecular weight of 30.
Polyoxyalkylene isocyanate component obtained by reacting 2,4-tolylene diisocyanate as an organic diisocyanate with a polyoxyalkylene polyol composed of a mixture of polypropylene glycol of 00 and polyoxypropylene triol having a molecular weight of 3000 (isocyanate group content 2 .6%) was prepared.

Next, the curing agent composition was blended in a ratio of 280 parts to 100 parts of the main component to obtain an elastic sealant according to the present invention.

[0074]

Example 7 [Preparation of Curing Agent] 2-Ethylhexyl Acrylate 16
0 part, methacrylic acid-2,2,6,6-tetramethylpiperidyl 4 parts, isopropyl alcohol 30 parts, α,
An acrylic low molecular weight copolymer was obtained in the same manner as in Example 1 except that 1 part of α'-azobisisobutyronitrile and 2 parts of n-dodecyl mercaptan were used. This has a viscosity of 15,000 poise (25°C, 6r
pm), the number average molecular weight by GPC was 3000, and the number of hydroxyl groups per molecule was 3.8.

[Preparation of Main Agent] As the main agent, the molecular weight is 30
Polyoxyalkylene isocyanate component obtained by reacting 2,4-tolylene diisocyanate as an organic diisocyanate with a polyoxyalkylene polyol composed of a mixture of polypropylene glycol of 00 and polyoxypropylene triol having a molecular weight of 3000 (isocyanate group content 2 .6%) was prepared.

Next, the curing agent composition was blended in a ratio of 280 parts to 100 parts of the main component to obtain an elastic sealant according to the present invention.

[0077]

Comparative Example 1 In Example 1, the same amount of polyoxypropylene triol having a molecular weight of 4000 was used instead of the acrylic low molecular weight copolymer used as the curing agent. An elastic sealant for comparison was prepared in the same manner as in Example 1 except for the above.

[0078]

Comparative Example 2 An acrylic compound composition comprising 100 parts of n-butyl acrylate, 10 parts of acrylonitrile, 1.0 part of acrylic acid and 1.6 parts of thioglycolic acid was prepared. 30% of this compounded composition and a molecular weight of 3000
And 10 parts of polypropylene glycol in Example 2 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 substituting with nitrogen for about 60 minutes, 0.1 part of α,α'-azobisisobutyronitrile was added, and heat generation started immediately. After this exotherm became a little mild, 0.2 parts of α,α′-azobisisobutyronitrile was added to the rest of the above composition, and the mixture was gradually added to the flask by a dropping funnel in about 3 hours. It was After that, the time when the exotherm was not observed was taken as the end point of the polymerization.

The acrylic-polyoxyalkylene-based composition thus obtained had a viscosity of 250 poise (30° C., 2 rpm) as measured by a B-type rotational viscometer. To 100 parts of this composition, 100 parts of calcium carbonate, 23 parts of titanium dioxide, 1.6 parts of Disparlon 3600N (Kusumoto Kasei Co., Ltd., a polyether ester type surfactant), and 0.5 parts of dibutyltin dilaurate were added, and kneader was used. After premixing, the mixture was further kneaded with a three-roll mill to obtain a curing agent blending system for an elastic sealant.

As the main agent, a polyoxyalkylene polyol composed of a mixture of 100 parts of polypropylene glycol having a molecular weight of 3000 and 30 parts of polyoxypropylene triol having a molecular weight of 3000 was reacted with 2,4-tolylene diisocyanate as an organic diisocyanate. Using the obtained polyoxyalkylene isocyanate component (content of mesocyanate group: 2.85%), the main component 10
An elastic sealant of a comparative example was prepared by blending 30 parts of this main agent with 100 parts of the curing agent compounding system so that the curing agent was about 150 parts with respect to 0 part.

Using the elastic sealants of Examples and Comparative Examples thus obtained, tensile adhesion test, durability test, weather resistance test, adhesion test of finish coating material, coating of finish coating material A contamination test and a tack evaluation test were examined. The results are shown in Tables 2 to 4 below. Further, the above characteristics were examined by the methods shown below.

(1) Tensile Adhesion Test A test piece was prepared by a test method according to JIS A 5758, and a tensile test was conducted after standard curing and heating curing.
The adhesive performance was measured by using 50% tensile stress, maximum tensile stress, elongation at break, and break condition.

(2) Durability test A durability test was conducted by a test method according to the durability category 9030 of JIS A 5758.

(3) Weather resistance test A sealing agent was placed in a size of length×width×height=50 mm×50 mm×10 mm, and after initial curing (7 days at 20° C. and then 7 days at 50° C.). The test piece was irradiated with a sunshine weatherometer tester for 2000 hours. The weather resistance was determined by visually observing the deterioration of the surface.

(4) Adhesion test of finish coating materials After initial curing of the sealing agent, each finish coating material was applied, and 2
Aged at 0° C. for 14 days. In addition, the adhesion performance, after curing,
It was evaluated by the cross-cut method.

(5) Coating Contamination Test of Finishing Coating Material After the initial curing of the sealing agent, each finishing coating material was applied, and 1
I was exposed outdoors for two months. The stains, discoloration, etc. of the finish coating material were visually observed.

(6) Tack evaluation test The sealing agent was aged at 20° C. for 2 days, and the surface was evaluated by touching with a finger.

[0088]

[Table 1]

[0089]

[Table 2]

From Tables 1 and 2 above, the elastic sealants of the examples have no difference in rubber physical properties after standard curing and heat curing in the tensile adhesion test, pass the durability classification 9030, and satisfy the sunshine weatherometer. The surface did not deteriorate even after irradiation for 2000 hours. Further, the adhesion of the finish coating material is excellent, and the coating contamination of the finish coating material is also excellent.
Moreover, almost no tack was observed on the surface of the sealing agent.

On the other hand, the comparative products show a difference in the physical properties of the rubber after the standard curing and the heat curing in the tensile adhesion test, and are inferior in durability and weather resistance. Further, the adhesion of the finish coating material and the coating stain resistance of the finish coating material are slightly inferior. Also, the tack of the surface of the sealing agent was considerably recognized.

Claims (1)

[Claims] 1. A two-pack type sealant composition comprising the following main agent (A) and curing agent (B). (A) A polyoxyalkylene-based isocyanate having an isocyanate group at a molecular end obtained by reacting a polyoxyalkylene polyol having an average molecular weight of 300 to 6000 with an organic diisocyanate. (B) Acrylic low molecular weight (co-reactant obtained by reacting a monomer mixture consisting of the following (a), (b) and at least one of (c) and (d) in the presence of (e) ) Polymer. (A) A functional unsaturated monomer having one hydroxyl group or amino group in the molecule as a functional group capable of reacting with an isocyanate group. (B) (Meth)acrylic acid alkyl ester. (C) At least one unsaturated monomer selected from the group consisting of vinyl acetate, vinyl propionate, acrylonitrile, styrene and acrylamide. (D) A functional unsaturated monomer having one carboxyl group, epoxy group or hydrolyzable group in the molecule. (E) A polymerization initiator or a chain transfer agent. [However, in the above (b), (c) and (d), (b)
At least one of (c) and (d) is 0 to 50% by weight with respect to 100 to 50% by weight, and the amount of (a) used is (b) and at least one of (c) and (d). It is within the range of 1/10 to 1/500 mol of the total amount used. The amount of (e) used is 0.1 to 30 parts by weight per 100 parts by weight of the monomer mixture consisting of (a), (b), (c) and/or (d). ]