JP2002338948A - Sealant composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sealant composition which can develop weathering resistance and staining resistance and does not suffer a decrease in a curing rate even after being stored. SOLUTION: The sealant composition comprises (A) an oxyalkylene polymer containing at least one reactive silyl group in the molecule, (B) a polymer based on an acrylic ester with a 1-20C ester moiety and having a glass transition temperature of at most 10 deg.C and a weight-average molecular weight of 500-20,000, (C) a hydrolyzable silane having a group that forms an amino group upon being hydrolyzed, (D) an organotin compound, and (E) a filler.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable composition which can be cured at room temperature, and more particularly to a sealing material composition having a high curing rate even after storage.

[0002]

2. Description of the Related Art Conventionally, a sealing material has been an indispensable material in construction and civil engineering. In addition to the sealing base material, a filler, a plasticizer, a curing accelerator, an antioxidant, a thixotropy-imparting agent, and the like are added to the components of the sealing material. Of these, the plasticizer is mainly added to improve workability, and phthalic acid esters such as dioctyl phthalate and diisononyl phthalate are often used in many cases. Although phthalate-based plasticizers have been mainly used in sealing materials based on modified silicones, which are now widely used, they do not have sufficient weather resistance. In addition, there has been a problem that the bleeding of the surface occurs over time after the construction, causing self-contamination and peripheral contamination.

The present inventors have already proposed that contamination can be improved by using a plasticizer containing an acrylate ester as a main component (Japanese Patent Application No. 12-01950).
9) When this is applied to a one-component modified silicone-based sealing material, although weather resistance and stain resistance are improved,
There was a problem that the curing rate was significantly reduced after storage.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a sealing material which has weather resistance and stain resistance and does not decrease the curing speed even after storage.

[0005]

The present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, in a sealing material using an acrylic polymer as a plasticizer, an amino group by hydrolysis was used as an adhesion-imparting agent. It has been found that a sealing material containing a hydrolyzable silane having a group that produces a compound and an organotin compound not only has weather resistance and stain resistance, but also does not lower the curing rate after storage. That is, the present invention comprises (A) an oxyalkylene polymer having at least one reactive silyl group in one molecule, and (B) an acrylate having 1 to 20 carbon atoms in an ester moiety as a main component, A polymer having a glass transition temperature of 10 ° C. or less and a weight average molecular weight of 500 to 20,000, (C) a hydrolyzable silane having a group capable of generating an amino group by hydrolysis, (D) an organotin compound, E) A sealing material composition characterized by containing a filler.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION (A) contained in the composition of the present invention
The main chain skeleton of the oxyalkylene polymer containing at least one reactive silyl group in one molecule essentially has a repeating unit represented by the general formula (1).

[0007]

## STR1 ## -R ¹ -O- (1)

(In the formula, R ¹ is a divalent organic group, and is preferably a linear or branched alkylene group having 1 to 14 carbon atoms.) As a specific example of the repeating unit represented by the general formula (1),
_{-CH 2 O -, - CH 2} CH 2 O -, - CH 2 CH (C
_{H 3) O -, - CH} 2 CH (C 2 H 5) O -, - CH 2 C
_{(CH 3) 2 O -,} - CH 2 CH 2 CH 2 CH 2 O- and the like. The main chain skeleton of the oxyalkylene polymer may be composed of only one type of repeating unit, or may be composed of two or more types of repeating units. In particular, when used as a sealing material or the like, it is preferably formed of a polymer containing propylene oxide as a main component.

The reactive silyl group contained in the component (A) of the composition of the present invention includes a group represented by the following general formula (2).

[0010]

Embedded image _{^{- [- Si (R 2 2}} -a) (X a) -O-] m Si (R 3 3-b) -X b (2)

(Wherein R ² and R ³ are each an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms,
An aralkyl group having 7 to 20 carbon atoms or (R ⁴ ) ₃ SiO—
[R ⁴ is a monovalent hydrocarbon group having 1 to 20 carbon atoms;
R ⁴ may be the same or different], and when two or more R ² or R ³ are present, they may be the same or different. May be. X represents a hydrolyzable group;
When two or more exist, they may be the same or different. a represents 0, 1 or 2, and b represents 0, 1, 2 or 3. m general formulas (3)

[0012]

## STR3 ## ^{_{-Si (R 2 2-a)}} (X a) -O- (3)

A in the above need not be the same. m represents 0 or an integer of 1 to 19. However, (Σa + b) ≧ 1
Shall be satisfied.

The hydrolyzable group represented by X is not particularly limited, and may be a conventionally known hydrolyzable group. Specifically, a halogen atom, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an acid amide group, an aminooxy group, a mercapto group,
An alkenyloxy group and the like can be mentioned. Among these, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an aminooxy group, a mercapto group and an alkenyloxy group are preferred, and an alkoxy group is particularly preferred from the viewpoint of gentle hydrolysis and easy handling. .

This hydrolyzable group has one silicon atom
３3 can be combined, and (３a + b) is 1
A range of ~ 5 is preferred. When two or more hydrolyzable groups or hydroxyl groups are bonded to the reactive silyl group, they may be the same or different.

The number of silicon atoms forming the reactive silyl group may be one, or may be two or more. In the case of a silicon atom linked to a siloxane bond or the like, the number may be about twenty.

Among these reactive silyl groups, a group represented by the following general formula (4) is preferred in that it is easily available.

[0018]

Embedded image —Si (—R ³ _3-b ) (X _b ) (4)

In the formula, R ³ , X and b are the same as described above.

Specific examples of R ² and R ³ in the general formula (2) include, for example, an alkyl group such as a methyl group and an ethyl group, a cycloalkyl group such as a cyclohexyl group, and an aryl group such as a phenyl group. , An aralkyl group such as a benzyl group,
R ⁴ is a methyl group, a trimethylsiloxy group represented by R ⁴ ₃ SiO- can be mentioned a phenyl group. Of these, a methyl group is particularly preferred.

The plasticizer of the present invention contains acrylic acid ester as a main component (hereinafter referred to as an acrylic plasticizer). The ester portion of the acrylate ester has 1 to 1 carbon atoms.
20 are used.

Specifically, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, s-butyl acrylate, t-butyl acrylate, neopentyl acrylate, acrylic acid 2 Alkyl acrylates such as ethylhexyl, isodecyl acrylate, lauryl acrylate, tridecyl acrylate and stearyl acrylate; cycloaliphatic alkyl acrylates such as cyclohexyl acrylate, isobornyl acrylate and tricyclodecinyl acrylate; hydroxy acrylate Hydroxyalkyl acrylates such as ethyl, hydroxybutyl acrylate, hydroxypropyl acrylate and ε-caprolactone addition reaction product of hydroxyethyl acrylate; 2-methoxy acrylate Chill, dimethylaminoethyl acrylate, chloroethyl acrylate, and a hetero atom-containing acrylic acid esters such as trifluoroethyl acrylate and tetrahydrofurfuryl.
One or more of these may be polymerized.

It is also possible to copolymerize copolymerizable monomers other than acrylic acid esters. For example,
Examples include vinyl monomers such as methacrylates, α-olefins, vinyl esters, and vinyl ethers.

The acrylic plasticizer is produced by ordinary radical polymerization, but a radical polymerization initiator may or may not be used.

Examples of the radical-generating polymerization initiator include peroxides such as diisopropylperoxydicarbonate, tert-butylperoxypivalate, benzoyl peroxide, lauroyl peroxide, and ditertiary butyl peroxide, and azobisisobutyrate. Azo compounds such as lonitrile and azobisisovaleronitrile, and inorganic peroxides such as ammonium persulfate and potassium persulfate can be used. The amount of the polymerization initiator to be used is preferably 5 parts by weight or less, more preferably 2 parts by weight or less, based on 100 parts by weight of the total amount of the monomers constituting the acrylate copolymer. If it is at least 5 parts by weight, the weather resistance will decrease. It is preferable not to use a chain transfer agent because it leads to a decrease in weather resistance.

As the polymerization method, ordinary methods such as suspension polymerization and emulsion polymerization in an aqueous medium, solution polymerization in an organic solvent, and bulk polymerization can be adopted.

In the case of solution polymerization, the organic solvent may be any of those usually used as solvents, for example, cyclic ethers such as tetrahydrofuran and dioxane; aromatic hydrocarbon compounds such as benzene, toluene and xylene; ethyl acetate and butyl acetate Esters; ketones such as acetone, methyl ethyl ketone and cyclohexanone; alcohols such as methanol, ethanol and isopropanol. One or more of these can be used.

The polymerization conditions include a polymerization temperature of 20 to 30.
The reaction can be carried out at 0 ° C. under normal pressure to 10 MPa, and in the case of pressurization, using a pressure resistant autoclave for a reaction time of 5 minutes to 20 hours. The polymerization method may be batch polymerization, semi-batch polymerization, or continuous polymerization.

The acrylic plasticizer of the present invention has a glass transition temperature of 10 ° C. or lower, preferably 0 ° C. or lower, more preferably -10 ° C. or lower. The weight average molecular weight is 50
It is preferably from 0 to 20,000, and 700
More preferably, it is at least 10,000. When the glass transition temperature is higher than 10 ° C., workability at a low temperature becomes poor. On the other hand, if the weight average molecular weight exceeds 20,000, sufficient plasticity cannot be obtained, and the workability also deteriorates. On the other hand, when it is less than 500, the low molecular polymer bleeds, so that the contamination is reduced.

The amount of addition is based on 100 parts by weight of (A)
(B) 1 part by weight to 150 parts by weight, preferably 5 parts by weight
120 parts by weight is more preferred. More preferred is 10 to 100 parts by weight. If the amount is less than 1 part by weight, the effect as a plasticizer is lost. On the other hand, if the amount is more than 150 parts by weight, bleeding occurs on the surface, and the contamination becomes worse.

In the present invention, (C) a hydrolyzable silane having a group capable of forming an amino group by hydrolysis is added. This is to enhance the adhesion to the adherend. Usually, a hydrolyzable silane having an amino group is used as a sealing material. In this case, curing may be delayed after storage. However, when the silane of the present invention is used,
This is improved.

The group that generates an amino group by hydrolysis has, for example, a ketimine structure and the like.
It is a group that forms _two groups or a —NHR group (R is an alkyl group). Further, the hydrolyzable silyl group is represented by (A)
This is the same as (4) described above. However, (A)
May be the same or different.

More specifically, dimethyl keto iminopropyl trimethoxy silane, dimethyl keto imino propyl triethoxy silane, methyl ethyl keto imino propyl trimethoxy silane, methyl ethyl keto imino propyl triethoxy silane, methyl isobutyl keto imino propyl trimethoxy silane, methyl isobutyl keto silane Examples include iminopropyldimethoxymethylsilane and methylisobutylketiminopropyltriethoxysilane.
One or more of these may be used.

[0034] The addition amount is based on 100 parts by weight of (A).
(C) 0.1 to 10 parts by weight is preferred. More preferably, it is 0.2 to 7 parts by weight, and still more preferably 0.5 to 5 parts by weight. When the amount is less than 0.1 part by weight, the adhesion to the adherend is insufficient, and when the amount is more than 10 parts by weight, the weather resistance decreases.

In the present invention, (D) an organotin compound is used.
This is a catalyst for subjecting the reactive silyl groups of (A) to a condensation reaction with moisture. Specific examples include dibutyltin dilaurate, dibutyltin mercaptide, dibutyltin thiocarboxylate, dibutyltin dimaleate, dibutyltin diacetate, dibutyltin diacetacetonate, tin octylate, and dioctyltin dimaleate. Among them, dibutyltin diacetacetonate is
It is preferable because the reaction speed is higher than other catalysts.

The amount of addition was 100 parts by weight of (A)
(D) 0.1 to 10 parts by weight is preferred. More preferably, it is 0.2 to 7 parts by weight, and still more preferably 0.5 to 5 parts by weight. If the amount is less than 0.1 part by weight, curing is not sufficient, and if the amount is more than 10 parts by weight, weather resistance decreases.

In the present invention, a filler (E) is added. Thereby, mechanical properties are improved, and strength and elongation are improved. As a specific example, the average particle size is 0.02 to 2.0 μm
Light calcium carbonate, average particle size 1.0-5.0μ
m heavy calcium carbonate, titanium oxide, zinc oxide,
Carbon black, synthetic silicic acid, talc, zeolite,
Examples include mica, silica, calcined clay, kaolin, bentonite, aluminum hydroxide and barium sulfate. Among these, light calcium carbonate, heavy calcium carbonate, and titanium oxide, which are highly effective in improving physical properties, are preferred. The addition amount of the filler (E) is preferably 10 parts by weight to 300 parts by weight based on 100 parts by weight of (A). More preferably, the amount is 20 parts by weight to 250 parts by weight. When the amount of the filler is 10 parts by weight or less or 300 parts by weight or more,
It is not preferable because the mechanical properties of the sealing material are impaired.

Further, if necessary, ultraviolet absorbers such as benzophenone compounds, benzotriazole compounds and oxalic anilide compounds, light stabilizers such as hindered amine compounds, antioxidants such as hindered phenol compounds, hydrogenated castor oil, etc. Anti-dripping agents, dehydrating agents such as vinyltrimethoxysilane, methyl orthoformate and methyl orthoacetate, coloring agents and organic solvents.

It is also possible to add an anti-tack agent. Specifically, Aronix M6100, M710
0, M8060, M8100 (all are polyester acrylates manufactured by Toa Gosei Co., Ltd.) and photocurable compounds represented by polyfunctional acrylic oligomers such as trimethylolpropane, and air curable compounds such as tung oil, linseed oil, polybutadiene, and unsaturated polyester. Compounds. These tackifiers may be used in combination. Polyfunctional acrylic oligomers are preferred because they have an excellent tack prevention effect. When a polyfunctional acrylic oligomer is used, it is more effective to use a photoinitiator in combination. Hereinafter, specific examples will be described.

[0040]

Examples <Examples 1 to 3 and Comparative Examples 1 and 2> In Examples, (A) MS polymer S was used as an oxyalkylene polymer containing at least one reactive silyl group in one molecule.
-203 (manufactured by Kanegafuchi Chemical Co., Ltd.), and (C) methylisobutylketoiminopropyltriethoxysilane (hereinafter referred to as adhesion-imparting agent 1) as a hydrolyzable silane having a group capable of producing an amino group by hydrolysis, The compounding with the curing accelerator and other fillers was performed as shown in Table 1 (each number is part by weight). In addition, (B) the carbon number of the ester part is 1
As a polymer which is an acrylate ester of -20, a plasticizer as shown in Table 2 was used. In Comparative Examples 1 and 2, dioctyl phthalate (hereinafter referred to as DOP) was used as the plasticizer instead of the polyacrylate. In Comparative Examples 2 and 3, N- (β was used as the adhesion-imparting agent instead of the hydrolyzable silane that generates an amino group by hydrolysis.
-Aminoethyl) -γ-aminopropyltrimethoxysilane (hereinafter referred to as “adhesion imparting agent 2”).

These blends were prepared immediately after blending and stored at 50 ° C. for one month according to JIS A-1439.
, A tack-free test was performed. Also, the test specimen immediately after blending was subjected to outdoor exposure in Funami-cho, Nagoya City for 6 months after indoor curing for one week, and the degree of dirt was visually evaluated according to the following criteria. ：: little dust adhered, 少 し little dust adhered, ×: considerable dust adhered. Further, for accelerated weather resistance test, samples were JIS 1
The sample was attached to a holder described in No. 439, placed in a sunshine weatherometer (manufactured by Suga Test Instruments) for 1,000 hours, and the surface state was observed, and evaluated according to the following criteria. ：: no cracks, Δ: slight cracks, ×: clear cracks The results are shown in Table 3.

[0042]

[Table 1]

1) Dibutyltin diacetacetonate 2) White luster CCR (manufactured by Shiraishi calcium) 3) Taipaque CR-97 (manufactured by Ishihara Sangyo) 4) A-171 (manufactured by Nippon Unicar) 5) Sanol LS-770 (manufactured by Sankyo) 6) Tinuvin 327 (manufactured by Ciba Specialty Chemicals) 7) Dispalon 6500 (manufactured by Kusumoto Chemicals)

[0044]

[Table 2]

[0045]

[Table 3]

[0046]

The sealing material composition of the present invention has good weather resistance and stain resistance, and does not reduce the curing rate even after storage, and is suitable as a building sealing material.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C08L 71/02 C08L 71/02

Claims (2)

[Claims] (1) an oxyalkylene polymer containing at least one reactive silyl group in one molecule; (B) an acrylate ester having an ester moiety having 1 to 20 carbon atoms; A polymer having a glass transition temperature of 10 ° C. or less and a weight average molecular weight of 500 to 20,000,
A sealing material composition comprising (C) a hydrolyzable silane having a group capable of generating an amino group by hydrolysis, (D) an organotin compound, and (E) a filler. 2. The ratio of each of the components (A) to (E) in claim 1 is 1 to 150 parts by weight of (B) and 0.1 part by weight of (C) with respect to 100 parts by weight of (A). -10 parts by weight, (D)
0.1 to 10 parts by weight and (E) 10 to 300 parts by weight of the sealing material composition.