JPH08225707A - Room temperature-curable composition - Google Patents

Abstract

PURPOSE: To obtain a room temperature-curable composition having sufficient elongation properties and tensile strength as a sealing material and having sufficient adhesiveness also to an adherend usually difficult to bond, e.g. a fluororesin steel plate. CONSTITUTION: This room temperature curable composition comprises (a) a polymer having at least one crosslinkable and hydrolyzable silyl group at the ends, (b) an acrylic copolymer having at least one crosslinkable and hydrolyzable silyl group and (c) a compound having an amino group and an alkoxysilyl group in one molecule.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a room temperature curable composition which reacts with moisture in the atmosphere to cure into a rubber, and has excellent adhesiveness to various adherends and is used as a sealing material or an adhesive. It relates to a useful room temperature curable composition.

[0002]

2. Description of the Related Art As a polymer which reacts with moisture in the atmosphere to cure into a rubber, it has at least one hydrolyzable silyl group at its terminal, and its main chain is essentially polypropylene oxide. It has been proposed to contain a polyether having a molecular weight of 6,300 to 15,000 as an active ingredient (for example, Japanese Examined Patent Publication No. 61-18582).
JP-A-3-72527, etc.).

Such a polyether is generally called a modified silicone resin and is useful as a base resin for a sealing material, but since it has essentially no adhesive property, it can be used as a silane coupling agent or a titanium coupling agent. Adhesives are needed. For the purpose of improving such adhesiveness,
It has been reported that a specific silane coupling agent is added (for example, JP-B-62-35421, JP-A-62-209164, etc.).

[0004]

However, although addition of a silane coupling agent improves the adhesiveness to ordinary adherends, it does not normally adhere to adherends such as fluororesin steel sheets. However, the adhesiveness is not sufficient, and the adhesiveness that is sufficiently satisfactory as a sealing material or an adhesive cannot be obtained.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a stretchable material having sufficient elongation and tensile strength as a sealing material, and at the same time, a fluororesin steel sheet or the like which is usually difficult to bond. It is an object of the present invention to provide a room temperature curable composition having sufficient adhesiveness to a body.

[0006]

The polyalkylene oxide which is the main chain of the polymer (a) used in the present invention includes, for example, polyethylene oxide, polypropylene oxide and polybutylene oxide, which are room temperature curable compositions. Polypropylene oxide is preferable in that it has good water resistance of the cured product and secures better elasticity as a sealing material. As the crosslinkable hydrolyzable silyl group, alkoxysilyl groups such as methoxysilyl and ethoxysilyl groups are preferable because they do not produce harmful by-products after the reaction.

When the number average molecular weight of the above-mentioned polymer becomes small, the elongation of the cured product becomes insufficient and the conformability to the joint surface decreases, and when it becomes large, the viscosity before curing becomes too high and the workability in the compounding step is improved. Therefore, it is preferably 4,
000 to 30,000, more preferably 1
The molecular weight distribution (MW
It is preferable that / Mn) is 1.6 or less because it has an excellent balance between workability and elongation of the cured product.

As the above-mentioned polymer (a), for example, "Cyryl 5A03" and "MS polymer" manufactured by Kanegafuchi Chemical Co., Ltd. and "Exestar 2410" manufactured by Asahi Glass Co., Ltd. are commercially available, and these can be used. . Also, as a mixture of the polymer (a) and a polymer (b) described later, "Cyryl MAX447" manufactured by Kanegafuchi Chemical Co., Ltd. is commercially available.

The copolymer (b) used in the present invention has an acrylic polymer as the main chain and has at least one crosslinkable hydrolyzable silyl group. For example, the following (1) To (4).

(1) As described in JP-A-54-36395, a (meth) acrylic acid ester polymer having an allyl group is represented by the following general formula in the presence of a Group VIII transition metal. A method of reacting with a hydrosilicon compound.

[0011]

Embedded image

(In the formula, R1 is a group selected from a monovalent hydrocarbon group and a halogenated monovalent hydrocarbon group, a is 0, 1 or 2, and X is selected from a halogen atom, an alkoxy group, an acyloxy group and a ketoximate group. Group or atom)

(2) As described in JP-A-57-179210, a chain transfer agent containing an alkyl (meth) acrylate, an alkyl (meth) acrylate containing an alkoxysilyl group, and a mercapto group. The method of copolymerizing in the presence of. (3) As described in JP-A-59-78222, copolymerization of an alkyl (meth) acrylate in the presence of a bifunctional radically polymerizable compound and a mercaptan containing an alkoxysilyl group as a chain transfer agent. How to make. (4) A method of polymerizing an alkyl (meth) acrylate using an azobisnitrile compound containing an alkoxysilyl group as a polymerization initiator, as described in JP-A-60-23405.

Among these copolymers (b), a polymer having a main chain of acrylic acid and an alkyl (meth) acrylate whose alkyl group has 1 to 12 carbon atoms is preferable from the viewpoint of flexibility, and further, A polymer composed of acrylic acid and an alkyl (meth) acrylate having an alkyl group with 2 to 8 carbon atoms is preferable. In particular, a polymer composed of methyl methacrylate is effective for improving the adhesiveness to the fluororesin steel sheet, and preferably, the portion composed of methyl methacrylate is 5% by weight or more, more preferably 20% by weight in the copolymer (b). It is more than weight%. If it is less than 5% by weight, the adhesiveness to the fluororesin steel sheet is lowered. Further, as the crosslinkable hydrolyzable silyl group, alkoxysilyl groups such as methoxysilyl and ethoxysilyl groups are preferable because they do not produce harmful by-products after the reaction.

If the molecular weight of the polymer (b) becomes small, the tackiness (stickiness) of the cured product becomes too large, and if it becomes too large, the miscibility with the polymer (a) decreases and the effect of improving the adhesiveness is not sufficient. , The number average molecular weight is 1,000 to 2
Those of 10,000 are preferable.

When the amount of the copolymer (b) added to the polymer (a) is small, the effect of improving the adhesiveness is not sufficient, and when the amount is too large, the curability and the elongation of the cured product are lowered, so that the weight of the copolymer (b) decreases. 0.1-100 with respect to 100 parts by weight of coalescence (a)
The amount is preferably part by weight, more preferably 0.5 to 80 parts by weight.

The compound (c) is a compound having an amino group and an alkoxysilyl group in one molecule as described above, and for example, 3-aminopropyltrimethoxysilane,
3-aminopropylmethylmethoxysilane, 3-aminopropyltriethoxysilane, -aminoethyl) -3-
Aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxyxysilane, N, N'-bis- [3- (trimethoxysilyl)
Propyl] ethylenediamine, N, N'-bis- [3-
(Triethoxysilyl) propyl] ethylenediamine,
N, N'-bis- [3- (methyldimethoxysilyl) propyl] ethylenediamine, N, N'-bis- [3-
(Trimethoxysilyl) propyl] hexamethylenediamine, N, N'-bis- [3- (triethoxysilyl)
Propyl] hexamethylenediamine, N, N'-bis-
[3- (Methyldimethoxysilyl) propyl] hexamethylenediamine, N, N-bis- [3- (trimethoxysilyl) propyl] ethylenediamine, N, N-bis-
[3- (methyldimethoxysilyl) propyl] ethylenediamine, N, N-bis- [3- (triethoxysilyl) propyl] ethylenediamine, N, N-bis- [3
-(Trimethoxysilyl) propyl] hexamethylenediamine, N, N-bis- [3- (methyldimethoxysilyl) propyl] hexamethylenediamine, N, N-bis- [3- (triethoxysilyl) propyl] hexamethylene Diamine, N, N-bis- [3- (trimethoxysilyl) propyl] amine, N, N-bis- [3- (triethoxysilyl) propyl] amine, N, N-bis-
Examples include [3- (methyldimethoxysilyl) propyl] amine.

When the amount of the above compound added to the polymer (a) is small, the effect of improving the adhesiveness is not sufficient, and when it is too large, the curability is deteriorated.
The amount is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 8 parts by weight with respect to 00 parts by weight.

The essential components of the room temperature curable composition of the present invention are:
As described above, a silanol condensation catalyst, a physical property adjusting agent, a plasticizer, a dehydrating agent, a filler, an anti-sagging agent and the like may be appropriately added in addition to the above essential components.

The silanol condensation catalyst is added for the purpose of promoting the moisture curing reaction. As this silanol condensation catalyst, known ones can be used, for example, dibutyltin dilaurate, dibutyltin maleate, dibutyltin oxide, dibutyltin diacetate, dibutyltin phthalate, dibutyltin bisacetylacetonate, dibutyltin bis (monoester). Maleate), dibutyltin octoate, tin octylate, dioctyltin oxide, tin compounds such as tin naphthenate, titanate compounds such as tetra-n-butoxytitanate, tetraisopropoxytitanate, dibutylamine-2-ethylhexoate. Such as amine salts, diisopropoxyaluminum ethyl acetoacetate and other organoaluminum compounds, zirconium tetraacetylacetonate, titanium tetraacetylacetonate and other chelate compounds, octyl Acid lead, and the like. The above silanol catalyst is used alone or 2
You may use together more than one kind.

When the amount of the silanol condensation catalyst added is small, the curing rate is low, and when it is large, the curing rate is high and the workability is deteriorated. Therefore, the amount is 0.1 to 10 with respect to 100 parts by weight of the polymer (a). Parts by weight are preferred.

The physical property modifier is added for the purpose of improving tensile properties. Examples of the physical property adjusting agent include silicon compounds having one silanol group in one molecule. Examples thereof include triphenylsilanol, trialkylsilanol, dialkylphenylsilanol, diphenylalkylsilanol, and the like. There is a silicon compound that decomposes to form a compound having one silanol group in one molecule, and examples thereof include triphenylmethoxysilane, trialkylmethoxysilane, dialkylphenylmethoxysilane, diphenylalkylmethoxysilane, triphenylethoxysilane, and triphenylethoxysilane. Alkyl ethoxysilane etc. are mentioned. The physical property modifiers may be used alone or in combination of two or more.

The above-mentioned plasticizer is added for the purpose of enhancing the elongation property after curing and lowering the modulus. Examples of the plasticizer include phosphates such as tributyl phosphate and tricresyl phosphate, phthalates such as dioctyl phthalate, fatty acid monobasic acids such as glycerin monooleate, dibutyl adipate and dioctyl adipate. And fatty acid dibasic acid ester, polyethylene glycol (PEG), and the like. The above plasticizers may be used alone or in combination of two or more kinds.

The dehydrating agent is added for the purpose of removing water during storage. Examples of the dehydrating agent include silane compounds such as vinyltrimethoxysilane, dimethordimethoxysilane, tetraethoxysilane, methyltrimethoxysilane, and methyltriethoxysilane.

When the amount of the dehydrating agent is small, the viscosity becomes thick during storage and gels, so that the storage stability is deteriorated, and when the amount is large, the curing time after construction becomes long, so the addition amount is 100 parts by weight of the polymerization (a). On the other hand, 0.1 to 10 parts by weight is preferable.

The above-mentioned filler is added for the purpose of reinforcing the cured product. Examples of the filler include calcium carbonate, magnesium carbonate, hydrous silicic acid, silicic acid anhydride, calcium silicate, silica, titanium dioxide, clay, talc, carbon black and the like. The above fillers may be used alone or in combination of two or more.

The above-mentioned anti-sagging agent is added for the purpose of suppressing sagging during work. Examples of the anti-sagging agent include hydrogenated castor oil derivatives, fatty acid amide wax, aluminum stearylates, barium stearylates and the like. The anti-sagging agent may be used alone or in combination of two or more kinds.

Furthermore, pigments, ultraviolet absorbers, antioxidants, flame retardants and the like may be added to the room temperature curable composition of the present invention as appropriate.

[0029]

The room temperature curable composition of the present invention is cured by incorporating a polymer (a) whose main chain is essentially a polyalkylene oxide and which has a crosslinkable hydrolyzable silyl group at its end. It is possible to give the body flexibility. In addition, an acrylic copolymer (b) having a crosslinkable hydrolyzable silyl group and a compound having an amino group and an alkoxysilyl group in one molecule are blended to give a difficult adherend such as a fluorine steel plate. Also, high adhesiveness can be obtained, and compatibility of the polymers (a) and (b) can be obtained.

[0030]

Embodiments of the present invention will be described below.
In the following, "parts" means "parts by weight".

Examples 1 to 15 and Comparative Examples 1 to 4 [Synthesis of Polymer (b)] Polymer (b) was obtained by the following method. (B-1 polymer) 2 with thermometer, cooling tube, dropping funnel
To a liter separable flask, charge 200 g of toluene, stir and purge with nitrogen, and use an oil bath for 80
After the temperature was raised to 0 ° C, a solution of 2 g of azobiscyclohexanecarbonitrile dissolved in 10 g of toluene was added, and to this was added 150 g of n-butyl acrylate, 160 g of methyl methacrylate, 20 g of 3-methacryloxypropyltrimethoxysilane, and 3-mercapto. A mixed solution of 25 g of propyltrimethoxysilane was added dropwise over 2 hours for polymerization.

3 hours after the end of the dropping, a solution of 2 g of azobiscyclohexanecarbonitrile dissolved in 10 g of toluene was additionally added, and the mixture was heated and stirred for 2 hours to complete the polymerization reaction, and the solid content was 70.2%. A reaction solution (an acrylic copolymer having a crosslinkable hydrolyzable silyl group) was obtained. The acrylic copolymer having a crosslinkable hydrolyzable silyl group has a styrene-equivalent molecular weight of 5,300 as determined by gel permeation chromatography (hereinafter referred to as GPC), and has a weight average molecular weight of It was 9,900.

(B-2 Polymer) 200 g of toluene was charged into a 2 liter separable flask equipped with a thermometer, a cooling tube and a dropping funnel, and the temperature was raised to 80 ° C. in an oil bath while stirring and purging with nitrogen. , 2 g of azobiscyclohexanecarbonitrile was added to 10 g of toluene, and 500 g of methyl methacrylate, 50 g of 3-methacryloxypropyltrimethoxysilane, and 3-
A mixed solution of 25 g of mercaptopropyltrimethoxysilane was added dropwise for 1 hour for polymerization.

After 3 hours from the end of the dropping, a solution of 2 g of azobiscyclohexanecarbonitrile dissolved in 10 g of toluene was additionally added, and after 3 hours, a solution of 2 g of azobiscyclohexanecarbonitrile dissolved in 10 g of toluene was added and then 2 hours were added. Continue heating and stirring to complete the polymerization reaction,
A reaction solution having a solid content of 68.3% (crosslinkable hydrolyzable silyl group-containing acrylic copolymer) was obtained. The acrylic copolymer having a crosslinkable hydrolyzable silyl group has a styrene-equivalent molecular weight by GPC of 28,300 in terms of number average molecular weight and 4,90 in terms of polymerization average molecular weight.
It was 0.

For comparison, a simple acrylic copolymer and a styrene polymer having a crosslinkable hydrolyzable silyl group were obtained by the following method instead of the copolymer (b). Acrylic copolymer (B-3 polymer) 200 g of toluene was charged into a 2 liter separable flask equipped with a thermometer, a cooling tube, and a dropping funnel, and heated to 80 ° C in an oil bath while stirring and purging with nitrogen. After that, a solution of 2 g of azobiscyclohexanecarbonitrile dissolved in 10 g of toluene was added, and 150 g of n-butyl acrylate, 350 g of methyl methacrylate,
A mixed solution of 25 g of dodecyl mercaptan was added dropwise over 2 hours for polymerization.

After 3 hours from the end of the dropping, a solution of 2 g of azobiscyclohexanecarbonitrile dissolved in 10 g of toluene was additionally added, and after a further 3 hours, a solution of 2 g of azobisisobutyronitrile dissolved in 10 g of toluene was added.
Continue heating and stirring for an hour to complete the polymerization reaction and the solid content to 6
A 9.0% reaction solution (acrylic copolymer) was obtained. The styrene-equivalent molecular weight of the acrylic copolymer by GPC was 51,300 in number average molecular weight and 9,100 in weight average molecular weight.

Styrene polymer having crosslinkable hydrolyzable silyl group (B-4 polymer) In a 2 liter separable flask equipped with a thermometer, a cooling tube and a dropping funnel, 480 g of styrene and 3-methacryloxypropyl 20 g of trimethoxysilane, 25 g of 3-mercaptopropyltrimethoxysilane and 200 of toluene
After charging g, stirring and nitrogen purging, the temperature was raised to 80 ° C. in an oil bath, a solution of 2 g of azobiscyclohexanecarbonitrile dissolved in 10 g of toluene was added, and 3 hours later, 2 g of azobiscyclohexanecarbonitrile was added to toluene. A solution dissolved in 10 g was additionally added, and after 3 hours, a solution prepared by dissolving 2 g of azobisisobutyronitrile in 10 g of toluene was added, and the mixture was heated and stirred for 2 hours, and the polymerization reaction was terminated to give a solid content of 69.1. % Reaction solution (styrene polymer having a crosslinkable hydrolyzable silyl group) was obtained. The styrene-converted molecular weight by GPC of the styrene polymer having a crosslinkable hydrolyzable silyl group was 5,500 in number average molecular weight and 8,900 in weight average molecular weight.

[Preparation of Room-Temperature Curable Composition] Each of the compositions shown in Tables 1 to 4 is uniformly mixed under reduced pressure with a mixing stirrer that is closed so that moisture does not enter from the outside, and the room-temperature curable composition is prepared. I got a thing. The calcium carbonate and titanium oxide used were those previously reduced in pressure at 110 ° C. Further, as the polymer (a) having the composition shown in Tables 1 to 4, the following were used. "MS polymer S303": trade name, manufactured by Kaneka Corporation "MS polymer S203": trade name, manufactured by Kaneka Chemical "MS polymer S903": product name, manufactured by Kaneka Corporation A mixture in which an acrylic copolymer having at least one silyl group and propylene glycol having a crosslinkable hydrolyzable silyl group at the terminal are uniformly dispersed.3% by weight of a portion composed of methyl methacrylate) ESS2410 ": trade name, manufactured by Asahi Glass Co., Ltd., number average molecular weight 17,000, MW / Mn = 1.
4 "Cyryl MAX447": trade name, manufactured by Kaneka Kagaku Co. (acrylic copolymer having at least one crosslinkable hydrolyzable silyl group, and propylene glycol having a crosslinkable hydrolyzable silyl group at the end Is a uniformly dispersed mixture of 40% by weight of methyl methacrylate) "N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane": Shin-Etsu Chemical Co., Ltd., trade name "K"
BM602 "

"N- (2-aminoethyl) -3-aminopropyltrimethoxysilane": manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM603"

The room-temperature curable composition obtained by the above method was evaluated for adhesiveness according to JIS A5758.
That is, using a fluororesin steel sheet (manufactured by Daido Steel Sheet Co., Ltd.) and a vinyl chloride resin steel sheet as adherends, and using the room temperature curable composition immediately after the above adjustment, an H-shaped test piece based on JIS A5758 was prepared, After curing for 2 weeks in a constant temperature and humidity of 23 ° C. and 60% RH, and further for 2 weeks in a constant temperature chamber of 30 ° C., a tensile test is performed at a speed of 50 mm / min to measure the maximum tensile strength and the maximum elongation. Then, the fracture morphology was observed. The evaluation results are shown in Tables 1 to 4.

[0041]

[Table 1]

[0042]

[Table 2]

[0043]

[Table 3]

[0044]

[Table 4]

[0045]

EFFECTS OF THE INVENTION According to the room temperature curable composition of the present invention, it is excellent in flexibility after curing and has sufficiently high adhesion even to an adherend such as a fluororesin steel plate which is usually difficult to adhere to. It exhibits good properties and can be suitably used as a sealing material, an adhesive, etc.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Koji Yamauchi 3-5-1 Chikko Shinmachi, Sakai City, Osaka Prefecture Sekisui Chemical Co., Ltd.

Claims (1)

[Claims] 1. A polymer whose main chain is essentially a polyalkylene oxide and which has at least one crosslinkable hydrolyzable silyl group at its terminal, and (b) a crosslinkable hydrolyzable polymer. At least 1 silyl group
A room temperature curable composition comprising: an acrylic copolymer having one of the above compounds; and (c) a compound having an amino group and an alkoxysilyl group in one molecule.