JP2000186176A - Alkoxysilyl group-containing curable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an alkoxysilyl group-containing curable composition improved in moisture permeability and surface residual tack and spinnability, etc., and especially useful as a sealing material for building by including a specific isobutylene-based polymer and a specific acrylic polymer as main ingredients. SOLUTION: This alkoxysilyl group-containing curable composition comprises (A) an alkoxysilyl group-containing isobuthylene-based polymer of the formula [(m) and (n) are each 5-400] and (B) an alkoxysilyl group-containing acrylic polymer incompatible with the component A as main ingredients. The weight ratio of the component A to the component B is preferably (50/50) to (5/95) when both components are together used so as to be one pack type moisture curable or preferably (95/5) to (5/95) when both components are combined with a curing agent in which a catalyst for hydrolyzing an alkoxysilyl group is compounded to afford two-pack type. The component B is obtained by subjecting an alkyl acrylate to radical copolymerization with a (meth)acryloxyalkoxysilane, etc., in the presence of a chain transfer agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a curable composition containing an alkoxysilyl group, more specifically, an alkoxysilyl group-containing acrylic polymer which is incompatible with an alkoxysilyl group-containing isobutylene polymer as a main component. Accordingly, the present invention relates to a curable composition for improving moisture permeability, surface residual tack, spinnability, and the like, and particularly useful as a sealing material for construction.

[0002]

BACKGROUND OF THE INVENTION Problems to be Solved by the Invention
For example, an isobutylene-based polymer containing an alkoxysilyl group is used as a main component of the architectural sealing material. The isobutylene-based polymer contains an alkoxysilyl group at both molecular terminals, and generally contains moisture and moisture in the air ( Curing is caused by the hydrolysis reaction due to moisture) (having moisture curability). However, since the moisture permeability is poor when applying a sealing material, the so-called one-component moisture curability is insufficient, so that the two-component type is usually used in combination with a curing agent containing an appropriate catalyst. is there. In addition, since the position of the alkoxysilyl group is controlled at the molecular terminal, this isobutylene-based polymer has good cured physical properties, but has a large side chain molecular weight and an ether bond such as a polypropylene oxide chain. Since the rigid main chain portion is a C-C bond that does not have a high viscosity, the viscosity becomes high, and stringing (spinning property) occurs at the time of applying the sealing material, resulting in poor working efficiency. Use of a plasticizer can be considered for this improvement. However, when used in a large amount, surface residual tack and rubber elasticity are deteriorated, and further, the polymer content is reduced and the weather resistance is reduced. After the heat aging, the modulus increases and the elongation decreases remarkably, and the thread breaking property is improved by the thixotropic agent, but the elongation decreases.

[0003]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned drawbacks of the isobutylene-based polymer, and have found the following findings. If an alkoxysilyl group-containing acrylic polymer that is incompatible with the isobutylene-based polymer is added to the above-mentioned isobutylene-based polymer, both polymers are incompatible with each other, so polymer separation after addition and blending, and further, deterioration in physical properties of the cured product Is expected,
On the contrary, no polymer separation or bleeding was seen,
In addition, both polymers become stable in a dispersed state with each other, greatly improving the viscosity, viscosity and spinnability, and the curing reaction progresses at the interface between the polymers, compatibilization progresses during curing, and the physical properties of the cured product decrease do not do. It is presumed that such an effect is based on the so-called "sea-island structure" in which the acrylic polymer is dispersed in the form of particles in the isobutylene polymer or in the acrylic polymer in the isobutylene polymer. You.

The present invention has been completed based on the above-mentioned findings, and is directed to an isobutylene-based polymer (A) containing an alkoxysilyl group and an acrylic polymer (B) which is incompatible with the isobutylene-based polymer (A). ) As a main component.

The above-mentioned isobutylene-based polymer (A) in the present invention is a monomer having a main chain skeleton composed of at least an isobutylene unit (if necessary, other than an isobutylene unit, a monomer copolymerizable with isobutylene (for example, having 4 to 4 carbon atoms). 12
Olefins, vinyl ethers, aromatic vinyl compounds,
Units such as vinyl silanes and allyl silanes) may be contained at both ends of the molecule.

Embedded image Wherein R and R ′ are the same or different and have 1 to 1 carbon atoms.
5 is lower alkyl; and a is an integer of 1 to 3], and has a molecular weight of 1,000 to 4,
0000, which means a waxy or high-viscosity liquid at room temperature, and can be produced by using an all-terminal functional isobutylene-based polymer obtained by a cationic polymerization method generally called an inifer method (JP-A-8-2317).
No. 58). Representative commercial products have the formula:

Embedded image Wherein n is 5-400 and m is 5-400.
The "Epion" series manufactured by Kanegafuchi Chemical Industry Co., Ltd. having the chemical structure of

Examples of the acrylic polymer (B) in the present invention include (a) alkyl acrylates (preferably having 2 to 4 alkyl carbon atoms) (for example, ethyl acrylate) disclosed in Japanese Patent Publication No. 3-80829. Propyl acrylate, n-butyl acrylate, isobutyl acrylate, amyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, n-octyl acrylate, etc.) and (b) vinylalkoxysilane (for example, vinyltrimethoxysilane, vinylmethyldimethoxy) Silane, vinyltriethoxysilane, vinyldimethylmethoxysilane, etc.) and (meth) acryloxyalkoxysilane (for example, γ-methacryloxypropyltrimethoxysilane, γ-meth One or a mixture of two or more selected from the group consisting of acryloxypropylmethyldimethoxysilane) with mercaptoalkoxylan (c) as a chain transfer agent (for example, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxy). Radical copolymerization [usually, α,
α′-azobisisobutyronitrile (AIBN), α,
Known methods such as bulk polymerization and solution polymerization using a polymerization initiator such as α'-azobisisovaleronitrile, benzoyl peroxide and methyl ethyl ketone peroxide; or a redox catalyst such as a transition metal salt, an amine or the like and a peroxide (By a redox polymerization method combining a system initiator) (usually having an average molecular weight of 3
000 to 100,000, and the average number of alkoxysilyl groups in one molecule is 1.5 to 3).

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The curable composition containing an alkoxysilyl group according to the present invention is made of a usual component such as a plasticizer except that the above-mentioned isobutylene-based polymer (A) and acrylic polymer (B) are used as main components. Agent [C ₆ -C ₁₂ alkyl ester of trimellitic acid; dibutyl phthalate,
Phthalates such as diheptyl phthalate, di (2-ethylhexyl) phthalate (DOP), butylbenzyl phthalate and butylphthalylbutyl glycolate; dibasic acid esters such as dioctyl adipate and dioctyl sebacate; fatty acid esters And the like; polyester plasticizers, etc.), fillers (heavy calcium carbonate, fatty acid-treated calcium carbonate, fumed silica, precipitated silica,
Carbon black, talc, titanium oxide, etc., adhesives (epoxy compounds, silane coupling agents, etc.), antioxidants (hindered phenols, mercaptans, sulfides, dithiocarboxylates, thioureas, thiophosphates) Thioaldehydes), anti-dripping agents (hydrogenated castor oil derivatives; metal soaps such as calcium stearate, aluminum stearate, barium stearate), coloring agents (inorganic and organic pigments, dyes, etc.),
Physical property modifiers (various silane coupling agents), water preservatives (water, hydrates of inorganic salts, etc.), ultraviolet absorbers (hindered amines, benzotriazoles, etc.), ozone deterioration inhibitors, light stabilizers, toners Etc. in an appropriate amount range.

Here, the weight ratio of the isobutylene-based polymer (A) to the acrylic polymer (B) is usually
(I) 50/50 to 5 /
95, preferably in the range of 45/55 to 10/90 [in this case, if the ratio of the acrylic polymer (B) is less than the lower limit (50/50), the isobutylene-based polymer having poor moisture permeability will be obtained. It becomes a matrix polymer (continuous phase), the water required for the curing reaction is not supplied promptly, the practical curing speed is lost, and if it exceeds the upper limit (5/95), the spinnability deteriorates and the residual (Ii) when a two-pack type curing agent is used in combination with a curing agent containing a catalyst for hydrolyzing the alkoxysilyl group, 95/5 to 5/95, preferably 90/10 In this case, if the ratio of the acrylic polymer (B) is less than the lower limit (95/5), the diffusion of water in the composition becomes slow and the reaction is necessary for the reaction. What At the same time when the partial becomes difficult to uniformly supply, when a high viscosity viscosity by spinnability is deteriorated, also greater than the upper limit value (5/95), deterioration of spinnability, tend to residual tack is severely]. The curing agent contains a curing catalyst (tin-based catalyst such as tin dioctylate, dibutyltin dilaurate, dibutyltin bisacetylacetonate, etc.) and a co-catalyst (such as a tertiary amine compound), a plasticizer, and a filler. Prepare by adding.

In the use of the above-mentioned plasticizer, an alkyl trimellitate ester is preferable. When this plasticizer is used, a change in modulus and a decrease in elongation during heat aging can be significantly suppressed. It is presumed that the main cause is that the volatilization loss at the time is small. The trimellitic acid alkyl ester alone or in combination with another plasticizer is used, and the total amount of the isobutylene polymer (A) and the acrylic polymer (B) is 100 parts (parts by weight, the same applies hereinafter).
May be blended in an amount of from 30 to 70 parts with respect to

[0010]

Next, the present invention will be described more specifically with reference to Production Examples, Examples and Comparative Examples. Production Example 1 (Production of acrylic polymer (B)) 77 g of trioctyl trimellitate (TOTM) was heated and stirred at 80 ° C. while replacing with nitrogen in a kolben, and 179.2 g of butyl acrylate and γ-mercaptopropyl were added thereto. Methyldimethoxysilane (0.756 g), γ-methacryloxypropylmethyldimethoxysilane (0.97 g)
4 g), a polymerization reaction is carried out at 80 to 85 ° C. while a mixture of 0.56 g of AIBN and 20 g of methanol is dropped over about 1 hour. After dropping, stirring is continued for 3 hours while maintaining the reaction temperature at 80 ° C., and methanol is removed under reduced pressure to obtain a colorless, transparent, viscous liquid acrylic polymer. Viscosity (B-type viscometer, rotor No. 7, rotation speed 20 rpm)
80,000 to 130,000 cps.

Examples 1-4 and Comparative Examples 1 and 2 (in the case of one-pack type) (1) Curable composition "Epion EP505S" (manufactured by Kanegafuchi Chemical Industry Co., Ltd.) as the isobutylene polymer (A) Molecular weight about 200
0) and the acrylic polymer (B) obtained in Production Example 1 in combination with other components in the number of parts shown in Table 1 below to obtain a curable composition. In addition, aminosilanes were used as an adhesive; methanol was used as a stabilizer; benzotriazoles and hindered amines were used as antioxidants; and organotin compounds were used as catalysts.

(2) Performance test The following items were tested and the results are shown in Tables 1 and 2. i) Viscosity measurement The rotor No. was measured using a B-type viscometer. 7 and 2 rpm
viscosity at 20 ° C. (× 10 ⁴ c
ps) and the viscosity ratio [2 rpm / 10 rpm
m] is calculated. The acceptable viscosity at 20 ° C. and 10 rpm is about 200,000 to 400,000 cps. ii) Spinnability Under a condition of 20 ° C./65% RH, the composition is taken out into a beaker, stirred well with a glass rod, and then quickly pulled up, and the length of the attached material is read. ○: 10 mm or less, Δ: 10 to 20 mm, ×: 20 mm
Iii) Front and back touch drying time (TFT, h) The touch drying time at 20 ° C. and 65% RH is measured. Generally, the pass value is within 4 hours. iv) Depth of curing from the surface after one day The cured thickness (mm) after standing curing for one day in a shape of W × D = 10 mm × 10 mm. 1mm or more passes. v) Surface residual tack The bead of the above (iv) was subjected to finger touch judgment after curing for one week at 20 ° C and 65% RH. ：: No stickiness Δ: Feel sticky ×: Feel very sticky vi) Sheet physical properties Sheet having a thickness of about 1 mm (20 ° C., 65% RH × 1 week +)
(50 ° C. × 1 week) is measured according to JIS K6251. vii) Change in physical properties after heat resistance The above sheet was left in an oven under each condition for 24 hours, and physical properties were measured under standard conditions. The rate of change is displayed in comparison with the above-mentioned normal physical property values. viii) Change in physical properties after immersion in warm water Measured after immersing the above sheet in water at 100 ° C for 1 week. The rate of change is expressed in comparison with the normal physical property values as described above.

[0013]

[Table 1]

[Table 2]

Examples 5 to 7 and Comparative Examples 3 and 4 (in the case of a two-pack type) (1) Curable composition In accordance with the above Examples, the components shown in Table 3 below were blended to obtain a curable composition. Obtain the composition. Incidentally, paraffin-based process oils as oils; polyfunctional acrylic monomers as tack removers; benzotriazoles and hindered amines as ultraviolet absorbers; mixtures of pigments / plasticizers as toners; mixtures of tin dioctylate / laurylamine as curing agents Was used. (2) Performance test The test was performed in accordance with the above examples, and the results are shown in Tables 3 and 4.

[0015]

[Table 3]

[Table 4]

Tables 1 and 2 (one-pack type) and Tables 3 and 4
From the results of (two-pack type), all of Examples 1 to 7 in which an acrylic polymer was used in combination with an isobutylene-based polymer were improved in moisture permeability, surface residual tack and spinnability, and further improved in heat resistance and water resistance. It is recognized that it is excellent. The composition of the present invention is mainly used for building sealing materials,
In addition, sealing materials for automobiles, electric appliances, civil engineering,
In addition, it can be applied to adhesives, paints, coating materials, potting materials, molded products, and the like.

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Claims (8)

[Claims] 1. An alkoxysilyl group-containing isobutylene-based polymer (A) and the isobutylene-based polymer (A)
A curable composition containing an alkoxysilyl group-containing acrylic polymer (B), which is incompatible with the above. 2. A curing agent containing a catalyst for hydrolyzing an alkoxysilyl group is combined, and the weight ratio of the isobutylene polymer (A) to the acrylic polymer (B) is 95/5.
The alkoxysilyl group-containing curable composition according to claim 1, which is of a two-pack type set within a range of from 5 to 95/95. 3. The one-pack type moisture-curable alkoxy according to claim 1, wherein the weight ratio of the isobutylene-based polymer (A) and the acrylic-based polymer (B) is set in the range of 50/50 to 5/95. A silyl group-containing curable composition. 4. An acrylic polymer (B) comprising (a) an alkyl acrylate and (b) one or a mixture of two or more selected from the group consisting of vinylalkoxysilane and (meth) acryloxyalkoxysilane. The compound is produced by radical copolymerization in the presence of a mercaptoalkoxysilane (c) as a chain transfer agent.
4. The curable composition containing an alkoxysilyl group according to any one of items 1 to 3. 5. The alkoxysilyl group-containing curable composition according to claim 4, wherein the alkyl acrylate (a) has 2 to 4 alkyl carbon atoms. 6. C ₆ -C of trimellitic acid as a plasticizer
The alkoxysilyl group-containing curable composition according to any one of claims 1 to 5, further comprising a ₁₂ alkyl ester. 7. As a plasticizer, one or a mixture of two or more selected from the group consisting of phthalic esters, dibasic esters, fatty acid esters, and polyester plasticizers, in addition to trimellitic acid alkyl esters. The curable composition containing an alkoxysilyl group according to claim 6. 8. The total blending amount of the plasticizer is 10 in total of the isobutylene-based polymer (A) and the acrylic polymer (B).
The alkoxysilyl group-containing curable composition according to claim 6 or 7, which is 30 to 70 parts by weight based on 0 part by weight.