JPS61133201A - Room temperature curable elastic composition - Google Patents

Abstract

PURPOSE:To provide a water or moisture-curable composition suitable for elastic sealant, consisting mainly of a polymer prepared by polymerization of acrylic ester monomer in the presence of silane compound as a chain transfer agent and radical initiator. CONSTITUTION:The objective composition consisting mainly of a polymer pre pared by polymerization of (A) at least one sort of acrylic ester mononer of formula I (R1 is 2-8C alkyl)(e.g., ethyl acrylate, n-octyl acrylate) using, as a chain transfer agent, (B) a Silane compound of formula II or III (R2 is OCH3, OC2H5 etc.; R3 is 1-4C alkyl; a is 0-2; X is Cl or Br)(e.g., methyl diethoxysilane) in such a molar ratio (B)/(A) as to be pref. 1/0.005-1/0.1 in the presence of (C) a radical initiator (e.g., 2,2'-azobisisobutylonitrile). EFFECT:Highly resistant to light, heat and stain with good weatherability and durability, also being inexpensive.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a room-temperature curable elastic composition, more specifically, a moisture or moisture curable elastic composition suitable for use as an inexpensive elastic sealant with excellent light resistance, weather resistance, heat resistance, durability, and stain resistance. The present invention relates to a curable copolymer composition.

Elastic sealants are indispensable materials in various industries such as architecture, civil engineering, vehicles, and electrical equipment, and their usage is increasing year by year.

Currently, various polymer compositions such as polyurethane-based, polyacrylic emulsion-based, modified silicone-based, polysulfide-based, and silicone-based polymer compositions are used as elastic sealants. Among these, silicone-based materials, particularly two-component silicone-based materials, are particularly useful as architectural sealants because they have superior properties in terms of light resistance, weather resistance, heat resistance, and durability compared to other polymer compositions. However, the cost is high, and there are problems with contamination of surrounding parts and adhesion with the paint film applied to the surface of the elastic sealant, which is thought to be caused by the migration of low molecular weight polydimethylsiloxane in the composition. There is.

The present inventors conducted research to solve the problems of staining and adhesion while maintaining the excellent light resistance and other properties of the two-component silicone system, and found that a specific acrylic ester A copolymer obtained by polymerizing a monomer and a specific vinylalkoxysilane and (meth)acryloxyalkoxysilane in the presence of a mercapto group-containing chain transfer agent is created, and a polymer containing the copolymer as a main component is produced. An application for a combined composition is already pending (see Japanese Unexamined Patent Publication No. 179210/1983). However, the cured product of this composition has a low modulus strength (cutting strength) and often has a sticky surface, so it has drawbacks such as easy adhesion of dust and dirt.

Therefore, the inventors of the present invention have developed an even more in-depth solution in view of such problems. ,@
As a result of our research, we found that the above acrylic acid ester monomer (and other polymerizable monomers are used in combination as necessary) is polymerized in the presence of a specific silane compound and a normal radical initiator as a chain second agent. Then, it was discovered that the resulting polymer had an alkoxy or halogen silyl group at both ends of its molecular chain, and that the above-mentioned drawbacks were eliminated and the polymer had the desired physical properties.The inventors completed the present invention. It's arrived.

That is, the present invention provides at least one acrylic acid ester monomer represented by the formula (1): CH2=CHC0UR [wherein R1 is an alkyl group having 2 to 8 carbon atoms]. Formula as a chain second moving agent: % Formula %) [In the formula, R2 is a methoxy or ethoxy group, R3 is an alkyl group having 1 to 4 carbon atoms, 1 is 0, 1 or 2, and
is chloro or bromo] and (3) a polymer obtained by polymerization in the presence of a radical initiator. It is. The reaction chain mechanism of the acrylic acid ester monomer (1) (M ), the silane compound (2) [e.g. >5i-H], and the radical initiator (3) [1] in the polymer is as follows: 1) I・+H-3t-→IH+・5tK (start] ii)
-/S i ・-1-n M −+ S i 10M Snow-, M, [: Growth] 1) 1) N Si (-M10M・+・
At St→-5i fM-f St -[stop]/
It is thought that the process proceeds as n \. Here, the silyl radical (・
The acrylic acid ester monomer (1) used in the present invention, in which primary radical termination is likely to occur because 5s-) is stable, and alkoxysilyl groups are formed at both ends, includes, for example, ethyl acrylate, propyl acrylate, n-
Butyl acrylate, imbutyl acrylate, amyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, n-
Straight chain, branched chain and alicyclic alkyl esters having 2 to 8 carbon atoms such as octyl acrylate are preferred, and at least one of these is used. If the number of carbon atoms is 1, the physical properties of the obtained polymer will be hard and brittle, and if the number of carbon atoms is 9 or more, the obtained polymer will not only have low strength but also tend to develop stickiness, which is not preferable.

Although it is possible to use a methacrylic ester monomer instead of the acrylic ester monomer described above, using this kind of methacrylic ester monomer is not preferable because the resulting composition may not have rubber elasticity. . However, within a range that does not impair the physical properties required for the final composition, usually 5
Other polymerizable monomers that can be polymerized with the acrylic ester monomer may be used in combination at a ratio of 0 mol% or less, preferably 20 mol% or less. Examples of such monomers include methacrylic esters ( Methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, inbutyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate,
Tetrahydrofurfuryl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl methacrylate, 2-methocinoethyl methacrylate, 2-ethoxyethyl methacrylate, etc.), acrylic esters other than the above (methyl acrylate, glycidyl acrylate, etc.) /-t, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, etc.), methacrylic acid, acrylic acid, vinyl acetate, vinyl propionate, vinyl non-sate (trade name Beoba, manufactured by Fel 1 Otsugaku), vinyl chloride, acrylonitrile , styrene, acrylamide, N-methylolacrylamide, vinylpyridine, maleic anhydride, vinylpyrrolidone, butadiene, and the like.

The above-mentioned silane compound (2) used in the present invention functions as a chain migration agent and also serves as a reaction component, introducing alkoxy or halogen silyl groups at both ends of the molecular chain of the resulting polymer. Examples of such silane compounds include methyldiethquinolane, dimethylethoxysilane, trimethoxysilane, dimethylmethoxysilane, methyldimethoxysilane, trimethoxysilane, ethyljethoxysilane, diethylethquinsilane, ethyljethoxysilane, diethyl Methoxysilane, propyljethoxysilane, probyldimethoxysilane, dipropylethoxysilane, dipropylmethoxysilane, butyldiethoxosilane, butyldimethoxysilane, dibutylethoxy7rane, diethylethquinsilane, tetrachlorosilane, tetrabromosilane. One or more of these are used.

The radical initiator (3) used in the present invention is one used in ordinary bulk polymerization and solution polymerization, such as 2,2'-azobisisobutyronitrile (AIBN).
, 42'-azobisisovaleronitrile, 2,2-azobis(2,4-dimethylvaleronitrile), benzoyl peroxide, L-butyroperoxide, methyl ethyl ketone peroxide, etc., and redox catalysts used in tsuredox polymerization ( Transition Δ
A combination of peroxide-based radical initiators and peroxide-based radical initiators may be employed.

The polymer which is the main component of the room temperature curable elastic composition according to the present invention includes the above-mentioned silane compound (2) and a radical initiator (
In the presence of 3), acrylic acid ester monomer (1) alone or in combination with other polymerizable monomers is radically polymerized using conventional methods (bulk polymerization method, solution polymerization method, etc.) and conditions. Manufactured by. In order to prevent gelation during the above polymerization, formula: % formula %) [In the formula, R4 is a divalent hydrocarbon group, R5 has a carbon number of 1 to 4
, R6 is a methoxy or ethoxy group, and b is 0, 1 or 2. In addition, in order to further improve the cured physical properties of the obtained polymer (particularly to obtain a tough cured product), the formula: % formula %) [In the formula, R7 is an alkyl group having 1 to 4 carbon atoms, and methoxy or ethoxy group, and C is 0.1 or 2 ] (e.g., vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinyltriethoxysilane, vinylmethyljethoxy7rane, etc.) Or formula: [In the formula, R9 is hydrogen or a methyl group, 10 is a divalent hydrocarbon group, R1□ is an alkyl group having 1 to 4 carbon atoms, and K.

is a methquine or ethoxy group, and d is 0.1 or 2. An appropriate amount of methyldimethoxinelan, r-(meth)acryloxypropyltriethoxysilane, r-(meth)acryloxypropylmethyldiethoxysilane, etc.) may be copolymerized.

The above acrylic acid ester monomer (1) and the 7-run compound (
In the usage ratio of 2), especially when the heavy body is used as a cooling material, usually 1 part of acrylic acid ester monomer is used.
The amount may be selected at 0.005 to 0.1, preferably 0.01 to 0.05 mol, of the silane compound. If the proportion of the silane compound is less than 0.005 mol, the viscosity of the resulting polymer will be high, and the curability of the polymer due to water or moisture will be insufficient. If the amount exceeds 0.1 mole, the cured physical properties of the polymer deteriorate and become brittle), which tends to make it uneconomical.

The polymer produced as described above has almost no frost formation after curing, is free from contamination due to adhesion of dust, and has excellent light resistance, weather resistance, and is comparable to conventional two-component silicone systems. It is recognized that it has heat resistance and durability, and imparts strong rubber elasticity, especially in terms of modulus strength.

The room temperature curable elastic composition according to the present invention is composed of the above polymer alone or by adding various additives for various uses to the polymer. In addition to sealing materials, it can also be used in a wide range of applications such as paints and adhesives. The application to tooling materials will be described in detail below.

For tooling material compositions, plasticizers, fillers, reinforcing agents, sagging agents, colorants, physical property regulators, stabilizers, adhesion promoters, curing accelerators, solvents, etc. are blended with the polymer as necessary. However, it has excellent light resistance, weather resistance, and heat resistance comparable to silicone-based sealants, even without the use of anti-aging agents that are required with conventional elastic tooling materials (polyurethane-based, modified/licone-based, etc.). It is extremely useful because it is durable and its manufacturing cost is much lower.

As plasticizers, dibutyl phthalate, dibutyl phthalate, di(2
- Heptaric acid esters such as ethylhexyl) phthalate, butyl benzyl phthalate, butyl phthalyl butyl glycolate; Non-aromatic dibasic acid esters such as dioctyl adipate and dioctyl sebacate; diethylene glycol dibenzoate, triethylene glycol dibenzoate, etc. esters of polyalkylene glycol;
Phosphate esters such as tricresyl phosphate and tributyl phosphate; chlorinated paraffins; aromatic hydrocarbon oils such as alkyldiphenyl and partially water ffi terphenyl, etc. Can be used alone or in combination of two or more. However, it is not necessarily necessary. In addition,
These plasticizers can also be blended during polymer production.

Fillers and reinforcing materials are used for purposes such as improving the properties (elongation, tensile strength, etc.) of the curable composition, adjusting properties, and reducing costs. Russoum carbonate surface treated with cationic surfactants, anionic surfactants, etc.; magnesium carbonate; talc; titanium oxide; barium sulfate; alumina; metal powders such as aluminum, zinc, iron, etc.; bentonite; kaolin clay; One or more of ordinary materials such as fumed silica powder, quartz powder, carbon black, and talc are used.

In particular, when the composition of the present invention is used, it has very excellent light resistance and weather resistance, so even if fillers and reinforcing materials that provide transparency, such as fume-dont strength, are used, the composition has sufficient light resistance and weather resistance that can be used outdoors. Give sex.

Examples of anti-sagging agents include hydrogenated castor derivatives; metal soaps such as calcium stearate, aluminum stearate, and barium stearate. There are cases.

As the coloring agent, ordinary inorganic or organic pigments, dyes, etc. can be used as required. The polymer according to the present invention is almost colorless and has excellent color fastness, so if the weather resistance of the pigments and dyes used is taken into consideration, excellent color tone can be maintained for a long time.

As the physical property modifier, various silane coupling agents such as alkylalkoxysilanes such as methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, and n-propyltrimethoxysilane; dimethyldiisopropenoxysilane, methyltriisopropenosilane, etc. Alkylisopropenoquine silanes such as xinlan, γ-glycidoxypropylmethyldiisopropenoquine silane: r-glycidoxypropylmethyldimethoxysolane,
r-glycidoxypropyltrimethoxyquinonerane, vinyltrimethoxinrane, vinyldimethylmethoxysilane,
γ-aminopropyltrimethoxy7norane, N-(β-aminoethyl)aminopropylmethyldimethoxysilane,
Alcoquine silanes having functional groups such as r-mercaptopropyltrimethoxine and γ-mercaptopropylmethyldimethoxine are added as necessary.

The alkoxy silanes are alkoxy silanes bonded to silicon atoms.
As the number of groups increases, the hardness tends to increase. Usually, the physical property modifier exhibits sufficient effects in an amount of about 5 parts or less per 100 parts (parts by weight, hereinafter the same) of the polymer used as the material for the sealant.

As a stabilizer, methanol,
Lower alcohols such as ethanol and various alkoxysilane-based silane coupling agents may be used in an amount of 10 parts or less per 100 parts of polymerization.

The adhesion promoter itself has adhesive properties to glass, other ceramics, metals, etc., and can be bonded to a wide range of materials by using various primers. Although it is not necessary, it is possible to improve adhesion to a wider variety of adherends by using one or more of various silane coupling agents, alkyl titanates, aromatic polyisonanates, etc. I can do it.

As curing accelerators, titanate esters such as tetrabutyl titanate and tetrapropyl titanate; organic tin compounds such as cyphthyltin dilaurate, dibutyltin maleate, dibutyltin diacetate, tin octylate, and silver naphthenate; lead octylate; butylamine, octylamine,
Dibutylamine, monoethanolamine, jetanolamine, triethanolamine, diethylenetriamine, triethylenetetramine, oleylamine, octylamine, cyclohexylamine, benzylamine, diethylaminopropylamine, xylylenediamine, triethylenediamine, guanidine, diphenylguanidine, 44. 6-tris(dimethylaminomethyl)phenol, morpholine, N-methylmorpholine, 1,3-diazabicyclo(5,4°6)undecene-7(DBU
) or salts of these carboxylic acids; low molecular weight polyamide resins obtained from excess polyamines and polybasic acids; reaction products of excess polyamines and epoxy compounds; silane coupling agents having amino groups; For example, γ-aminopropyltrimethoxine run, N
-(β-aminoethyl)aminopropylmethyldimethoxysilane or the like may be used alone or in combination as necessary.

Note that solvents may be added for the purpose of improving workability and reducing viscosity, such as aromatic hydrocarbon solvents such as toluene and xylene, and esters such as ethyl acetate, butyl acetate, amyl acetate, and cellosolve acetate. and ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and diisobutyl ketone. This solvent may be used during polymer production.

It is not necessary to add an anti-aging agent, or ordinary antioxidants and ultraviolet absorbers may be used.

Such a sealant composition can be prepared as a one-component type in which all the ingredients are mixed in advance and stored in a sealed container, and cured by the moisture in the air after installation. It can also be prepared as a two-component type in which components such as , plasticizer, water, etc. are blended in advance, and a single polymer composition is mixed with a main ingredient containing the above-mentioned compounding agents (materials) before use.

In the case of one-component type, all the ingredients are mixed in advance, so
It is preferable that a compounding agent (material) containing water is dehydrated and dried before use, or dehydrated during compounding and kneading by reducing pressure or the like.

In the case of a two-component type, there is no need to mix a curing catalyst with the main component containing a polymer, so there is little worry about gelation even if the compound (material) contains a small amount of water. When storage stability is required, dehydration and drying is preferred.

As the dehydration/drying method, suitable methods include heat drying for solid materials such as powder, and vacuum dehydration method for liquid materials, or dehydration methods using synthetic zeolite, activated alumina, silica gel, etc. Alternatively, dehydration may be carried out by blending a small amount of an incyanate compound and causing the incyanate group to react with water. In addition to such dehydration drying methods, lower alcohols such as methanol and ethanol, alkoxysilane compounds such as n-propyltrimethoxysilane, vinylmethyldimethoxysilane, r-mercaptopropylmethyldimethoxysilane, and γ-glycidoxypropyltrimethoxysilane are used. By adding it, storage stability is further improved.

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 100 g (0,781 mol) of n-butyl acrylate,
γ-acryloxypropylmethyldimethoxysilane 0.
5g (0,0021 mol), methyljethoxysilane O
85 (0,0037 mol) and λ2'-azobis(
4-dimethylvaleronitrile) 0゜1) 0.0004
Mol) is placed in a glass enclosure. This is cooled to -20°C, degassed using a vacuum pump, and then sealed with glass. When polymerization is carried out while this polymerization tube is kept in a constant temperature bath at 60° C., the viscosity of the contents increases in about 4 hours. Polymerization is continued for an additional 2 hours to complete the polymerization. The obtained polymer is a viscous liquid, and is subjected to a vacuum weight change method (non-volatile fraction method) at 105°C for 3 hours.
The polymerization rate was 88.2%.

After premixing 10 g of rutile-type titanium white, 90 g of fatty acid surface-treated calcium carbonate, and 10 g of toluene to the above polymer 1001, the mixture was uniformly kneaded using three rolls, and then degassed under reduced pressure for 5 minutes in a vacuum mixer. , a white paste-like non-sagging composition is obtained.

Add 0.21 F of dibutyltin dilaurate and 0.4 F of p-octylamine to the entire amount of this paste-like composition, mix thoroughly under reduced pressure to avoid air bubbles, and then spread it on a polyethylene plate into a sheet about 2 # thick. The mixture was then left to cure in a room at 20° C. and 65% RH for 5 days to obtain a cured sheet with no tackiness and rubber elasticity.

Regarding the above cured sheet, No. 3 dumbbell specified in JIS K-6301 and Shimadzu Autograph DC5-5
When the physical properties of the rubber were measured using 000 according to the regulations of JIS K-6301, the elongation rate was 500% and the cutting strength was 6.8 Ky/aA. Well, it was 140℃/
Surface deterioration of the composition was also observed in 48-hour heat aging and 500-hour irradiation using a sunshine weatherometer.
C0.05 mol) and 0.2-azobisisobutyronitrile. Polymerization is carried out in the same manner as in Example 1 using IS' (0,0006 mol) to obtain a colorless and transparent viscous polymer. Weight change method under reduced pressure at 105℃ for 3 hours (non-volatile fractionation method)
The polymerization rate was 65.7%.

Using the above polymer, a composition is prepared by adding the ingredients in the same manner as in Example 1, and then a cured sheet is prepared.

This cured sheet had no adhesive properties, and when its rubber properties were measured in the same manner as in Example 1, the elongation rate was 600%, and the cutting strength was 2.
1KIi/c+ (and was also good in heat aging and accelerated weathering tests.

Example 3 "-Butyl acrylate-) 1005' (0,781 mol)
, 8.5 f (0.05 mol) of tetrachlorosilane and 0.1 f (0,05 mol) of λ2-azobisisobutyronitrile
Polymerization was carried out for 30 minutes in the same manner as in Example 1 to obtain a colorless and transparent highly viscous polymerized product. 105℃×3
Polymerization rate 93 by time-decompression weight change method (non-volatile fraction method)
．． It was 6%.

When this polymer was left in the air, it cured in about 15 minutes while releasing hydrochloric acid and turned into a transparent adhesive resin with rubber-like elasticity.

Comparative Example 1 128.5 fI (1 mol) of butyl acrylate, 1.8 pco of acryloxypropylmethyldimethoxysilane,
While dropping a mixed solution of γ-mercaptopropylmethyldimethoxysilane (1.6FC0,009 mole), and 0.79 (0,004 mole) of 2.2-azobisisobutyronitrile into a separable flask, Polymerization was carried out at 70°C for 6 hours. The polymerization rate was 94% as determined by the reduced pressure weight change method (non-volatile content method).

A composition prepared by adding ingredients to the above polymer in the same manner as in Example 1 was formed into a sheet and cured. When the physical properties of the rubber were measured in the same manner as in Example 1, the elongation rate was 250%, the shear strength was 10.51'f/cd, and the surface adhesion was large.

As described above, the composition of the present invention has greater elongation, lower shear strength, and excellent rubber elasticity than the comparative example, and can be prepared without stickiness.

Claims (1)

[Claims] 1. Formula (1): CH_2=CHCOOR_1 [in the formula, R
_1 is an alkyl group having 2 to 8 carbon atoms] At least one acrylic ester monomer represented by (2) is used as a chain transfer agent with the formula: ▲There are numerical formulas, chemical formulas, tables, etc.▼ or Si- (X)
_4 [In the formula, R_2 is a methoxy or ethoxy group, R_3 is an alkyl group having 1 to 4 carbon atoms, a is 0, 1 or 2, and X is chloro or bromo] and (3) a radical 1. A room-temperature-curable elastic composition characterized in that the product is a polymer obtained by polymerization in the presence of an initiator. 2. Acrylic acid ester monomer (1) and silane compound (
2) wherein the molar ratio is 1/0.005 to 0.1.
The room temperature curable elastic composition described in 2.