JP2002332410A - Curing composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems that a cured product exhibiting sufficient physical properties cannot be obtained because curing does not occur or curability is lowered in the case where a catalyst is sometimes poisoned with an additive in a heat-curable composition, especially a curing composition utilizing a hydrosilylating reaction. SOLUTION: This curing composition consists essentially of the following components (A), (B), (C) and (D). (A) An organic polymer containing at least one alkenyl group capable of carrying out a hydrosilylating reaction in the molecule. (B) A curing agent containing at least two hydrosilyl groups in the molecule. (C) A hydrosilylating catalyst. (D) A hindered amine stabilizer containing an alkyl group bound to nitrogen atom in the piperidine skeleton.

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 improves the heat resistance of a cured product of an organic polymer which is cured by a hydrosilylation reaction, and further provides good mechanical properties.

[0002]

2. Description of the Related Art A curable composition in which an organic polymer having at least one alkenyl group in a molecule is crosslinked with a curing agent having two hydrosilyl groups in a molecule is disclosed in Japanese Patent Application Laid-Open No. 2-7 / 1990.
No. 5,644, and JP-A-3-181565. The cured product of this composition has excellent weather resistance, heat resistance, low moisture permeability and the like, and is expected to be used for a wide range of applications. However, for applications requiring heat resistance, such as electronic and electrical applications, further technology for improving heat resistance is required. For example, Japanese Patent Application Laid-Open No. 8-283048 and US Pat.
53743: citric acid, phosphoric acid,
Although the use of a sulfur-based antioxidant and the use of bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate are described, the curability may be reduced or desired physical properties may be obtained. There were some problems.

[0003]

In the case of a heat-curable curable composition, particularly a curable composition utilizing a hydrosilylation reaction, an additive may poison the catalyst. In that case, there is a problem that a cured product exhibiting sufficient physical properties cannot be obtained because the composition is not cured or the curability is reduced. For this reason, there has been a need to find a stabilizer that does not significantly reduce the curability of the composition and that exhibits sufficient physical properties after curing and ensures heat resistance.

[0004]

Means for Solving the Problems The present inventors have found that the addition of a hindered amine-based stabilizer in which an alkyl group is bonded to a nitrogen atom in a piperidine skeleton does not significantly reduce the curability of the composition. Thus, it has become possible to achieve both sufficient manifestation of physical properties of the cured product after curing and improvement in heat resistance.

That is, the present invention provides the following component (A):
(B) a curable composition comprising (C) and (D) as essential components; (A) an organic polymer containing at least one alkenyl group capable of hydrosilylation in a molecule, (B) a molecule A curing agent containing at least two hydrosilyl groups therein,
(C) a hydrosilylation catalyst; and (D) a hindered amine-based stabilizer in which an alkyl group is bonded to a nitrogen atom in a piperidine skeleton.

In a preferred embodiment, the invention relates to the above-mentioned curable composition wherein the organic polymer as the component (A) is a saturated hydrocarbon polymer.

A more preferred embodiment relates to the above-mentioned curable composition wherein the saturated hydrocarbon polymer as the component (A) is a polyisobutylene polymer.

[0008] In a further preferred embodiment, the present invention relates to the curable composition described above, wherein the total amount of the repeating units derived from isobutylene is 50% by weight or more.

In a further preferred embodiment, the present invention relates to the curable composition according to any one of the above, wherein the saturated hydrocarbon polymer as the component (A) has an alkenyl group at a terminal.

As a further preferred embodiment, the present invention relates to the curable composition according to any one of the above, wherein the curing agent of the component (B) is a polyorganohydrogenpolysiloxane containing at least two hydrosilyl groups in a molecule.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The component (A) used in the present invention is an organic polymer having at least one alkenyl group capable of undergoing a hydrosilylation reaction in a molecule. The alkenyl group capable of performing a hydrosilylation reaction is not particularly limited as long as it is a group containing a carbon-carbon double bond that is active in the hydrosilylation reaction. Examples of the alkenyl group include an aliphatic unsaturated hydrocarbon group such as a vinyl group, an allyl group, a methylvinyl group, a propenyl group, a butenyl group, a pentenyl group, and a hexenyl group, a cyclopropenyl group, a cyclobutenyl group, a cyclopentenyl group, and a cyclohexenyl group. And the like.

In the present invention, the component (A) preferably has 1 to 10 alkenyl groups in one molecule,
It is more preferable to have 1.1 to 4, more preferably 1.2 to 3. Further, the component (A) in the present invention desirably has the alkenyl group capable of undergoing the hydrosilylation reaction at the polymer terminal.
As described above, when the alkenyl group is at the polymer terminal, the amount of effective network chains of the finally formed cured product increases, and a high-strength, high-elongation rubber-like cured product is easily obtained. preferable.

Examples of the organic polymer in the present invention include a saturated hydrocarbon polymer, a polyoxyalkylene polymer, a polyester polymer, an acrylic polymer, a phenol polymer and the like. When used, a saturated hydrocarbon polymer is preferred from the viewpoint of low gas permeability and low moisture permeability. When the component (A) is a saturated hydrocarbon-based polymer, the polymer constituting the skeleton is (1)
(2) homopolymerizing a diene-based compound such as butadiene, isoprene or the like; or polymerizing an olefin-based compound having 1 to 6 carbon atoms such as ethylene, propylene, 1-butene or isobutylene as a main monomer. It can be obtained by a method such as copolymerizing a compound and a diene-based compound and then hydrogenating the compound. Isobutylene-based polymers, hydrogenated polybutadiene-based polymers, or hydrogenated polyisoprene-based polymers can be used to easily introduce a functional group into the terminal, easily control the molecular weight, and increase the number of terminal functional groups. Preferably it is.

In the isobutylene-based polymer, all of the monomer units may be formed from isobutylene units, and the monomer unit having copolymerizability with isobutylene is preferably 50% ( % By weight, the same applies hereinafter), more preferably 30% or less, particularly preferably 20% or less.

Examples of such monomer components include olefins having 4 to 12 carbon atoms, vinyl ethers, aromatic vinyl compounds, vinyl silanes and allyl silanes. Specific examples of such a copolymer component include, for example, 1-butene, 2-butene, 2-methyl-1-butene, 3-methyl-1-butene, pentene, and 4-methyl-
1-pentene, hexene, vinylcyclohexane, methylvinyl ether, ethylvinyl ether, isobutylvinyl ether, styrene, α-methylstyrene, dimethylstyrene, pt-butoxystyrene, p-hexenyloxystyrene, p-allyloxy Styrene, p-hydroxystyrene, β-pinene, indene, vinyldimethylmethoxysilane, vinyltrimethylsilane, divinyldimethoxysilane, divinyldimethylsilane, 1,3
Divinyl-1,1,3,3-tetramethyldisiloxane, trivinylmethylsilane, tetravinylsilane, allyldimethylmethoxysilane, allyltrimethylsilane, diallyldimethoxysilane, diallyldimethylsilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane and the like.

In the hydrogenated polybutadiene-based polymer and other saturated hydrocarbon-based polymers, similarly to the case of the isobutylene-based polymer, in addition to the monomer unit serving as the main component,
Other monomer units may be contained.

In the saturated hydrocarbon polymer used as the component (A) of the present invention, a double bond remains after polymerization, such as a polyene compound such as butadiene or isoprene, as long as the object of the present invention is achieved. A small amount of such monomer units,
Preferably, it may be contained in a range of 10% or less.

The saturated hydrocarbon polymer (preferably isobutylene polymer, hydrogenated polyisoprene or hydrogenated polybutadiene polymer) has a number average molecular weight (in terms of polystyrene by GPC method) of 100,000 or less, more preferably 500 to 500.
It is preferably about 100,000, particularly 1000 to
A liquid substance of about 40,000, that is, a substance having fluidity is preferred from the viewpoint of easy handling.

The method for producing the component (A) of the present invention is described in JP-A-3-152164 and JP-A-7-30490.
9, a method of reacting a compound having an unsaturated group with a polymer having a hydroxyl group or the like to introduce an unsaturated group into the polymer as disclosed in each of the publications. Examples of a method for introducing an unsaturated group into a polymer having a halogen atom include a method of performing a Friedel-Crafts reaction with alkenyl phenyl ether, a method of performing a substitution reaction with allyltrimethylsilane or the like in the presence of a Lewis acid, and a method of freeing various phenols. A method in which a Delft-Crafts reaction is performed to introduce a hydroxyl group, and then the above-described alkenyl group introduction method is further used in combination. Further, a method of introducing an unsaturated group during polymerization of a monomer as disclosed in U.S. Pat. No. 4,316,973, JP-A-63-105005, and JP-A-4-288309 is also possible.

The curing agent as the component (B) of the present invention is not limited as long as it contains at least two hydrosilyl groups in the molecule. Here, one hydrosilyl group refers to one SiH group. Therefore, when two hydrogen atoms are bonded to the same Si, it is calculated as two hydrosilyl groups.

As the component (B), an organohydrogenpolysiloxane is one of the preferable ones. Here, the organohydrogenpolysiloxane refers to a polysiloxane having a hydrocarbon group and a hydrogen atom on a Si atom, and when its structure is specifically shown,

[0022]

Embedded image And the like.

Among the above-mentioned various hydrosilyl group-containing groups, consideration is given to the fact that the hydrosilyl group-containing curing agent as the component (B) of the present invention has good compatibility with various organic polymers such as the component (A). In particular, the following are preferable.

[0024]

Embedded image The number of hydrosilyl groups contained in the component (B) may be at least two in one molecule.
-40 are preferred, and 3-30 are more preferred. In the case where the composition of the present invention is cured by a hydrosilylation reaction, if the number of the hydrosilyl groups is less than 2, curing is slow and curing failure often occurs. When the number of the hydrosilyl groups is more than 40, the stability of the curing agent (B) is deteriorated, and a large amount of the hydrosilyl groups remains in the cured product even after curing, which causes voids and cracks. Becomes

Further, in the curable composition of the present invention,
The ratio of the alkenyl group in the component (A) to the hydrosilyl group in the component (B) is usually from 1: 0.5 to 1: 5 in molar ratio.
, Preferably 1: 0.8 to 1: 3, more preferably 1: 1 to 1: 2.5. If the amount is less than 1 for the alkenyl group, a sufficiently cured cured product cannot be obtained. If the amount is more than 2.5 for the alkenyl group, the heat resistance may be deteriorated due to the influence of the remaining SiH.

The hydrosilylation catalyst which is the component (C) of the present invention is not particularly limited, and any catalyst can be used.

More specifically, solid platinum is supported on a carrier such as chloroplatinic acid, platinum alone, alumina, silica, and carbon black; a platinum-vinylsiloxane complex {for example, Ptn (ViMe ₂ SiOSiMe ₂ Vi)
n, Pt [(MeViSiO) ₄ ] m}; platinum-phosphine complex {for example, Pt (PPh ₃ ) ₄ , Pt (PB
u ₃ ) ₄ }; platinum-phosphite complex {for example, Pt [P
(OPh) ₃ ] ₄ , Pt [P (OBu) ₃ ] ₄ (where Me is
Represents a methyl group, Bu represents a butyl group, Vi represents a vinyl group, Ph represents a phenyl group, n and m represent integers, and Pt (ac
ac) ₂ , also U.S. Pat. No. 31,596 to Ashby et al.
No. 01 and 3159662.
Also included are hydrocarbon complexes, as well as the platinum alcoholate catalyst described in Lamoreaux et al., U.S. Pat. No. 3,220,972. In the platinum-vinylsiloxane complex of the present invention, the ratio of platinum (Pt) to the ligand is preferably platinum: ligand = 1: 0.2 to 1: 4 in molar ratio.

As an example of a catalyst other than a platinum compound,
Is RhCl (PPh_Three)_Three, RhCl _Three, Rh / Al
_TwoO_Three, RuCl_Three, IrCl_Three, FeCl_Three, AlCl_Three,
PdCl_Two・ 2H_TwoO, NiCl_Two, TiCl_Four, Etc.
Can be These catalysts may be used alone or in combination of two or more.
It may be used together. Chloroplatinic acid in terms of catalytic activity,
Platinum-olefin complex, platinum-vinylsiloxane complex,
Pt (acac)_TwoAre preferred. Especially for the amount of catalyst
There is no limitation, but 1 mol of alkenyl group in component (A)
10 for^-1-10^-8It is good to use in the range of mol.
Preferably 10^-2-10^-6Use in the range of mol
No. Also, hydrosilylation catalysts are generally expensive and corrosive.
In addition, a large amount of hydrogen gas is generated and the cured product foams
10^-1It is better not to use more than mole
Good. In the present invention, an alkane using a noble metal catalyst is used.
Curable composition by addition reaction of Si-H group to
Since the material is cured, the curing speed is very fast, and line production
It is convenient in performing.

As the hindered amine stabilizer having an alkyl group bonded to the nitrogen atom in the piperidine skeleton, which is the component (D) of the present invention, bis (1,2,2,6,6-pentamethyl-4-piperidyl) ) Sebacate, ADK STAB LA-62 or LA-63 (both manufactured by Asahi Denka Kogyo), 2-
(3,5-di-t-butyl-4-hydroxybenzyl)
Bis-n-butylmalonate (1,2,2,6,6-
Pentamethyl-4-piperidyl), dimethyl succinate
1- (2-hydroxyethyl) -4-hydroxy-2,
2,6,6-tetramethyl-4-piperidine polycondensate and the like. Among them, screws (1, 2, 2, 6, 6
-Pentamethyl-4-piperidyl) sebacate is preferred because it is a liquid and has good compatibility with a saturated hydrocarbon polymer. The hindered amine-based stabilizer is preferably used in an amount of 0.01 to 10 parts, more preferably 0.1 to 3 parts. 0.01
If the amount used is less than 10 parts, sufficient heat resistance may not be obtained, and if it is more than 10 parts, the curability may decrease.

The heat resistance is further improved by combining the hindered amine stabilizer (D) and other stabilizers, for example, a phenolic antioxidant and a benzotriazole stabilizer. As phenolic antioxidants, specifically, triethylene glycol
Bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) Propionate], 2,4-bis (n-octylthio) -6- (4-hydroxy-3,5
-Di-t-butylanilino) -1,3,5-triazine, pentaerythrityl-tetrakis [3-3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,2-thio-diethylenebis [3- (3,5-
Di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2-
Thiobis (4-methyl-6-t-butylphenol),
N, N'-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide), 3,5-
Di-tert-butyl-4-hydroxy-benzylphosphonate-diethyl ester, 1,3,5-trimethyl-
2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl- 4
-Ethylphenol, α-methylbenzylphenol,
Di (α-methylbenzyl) phenol, tri (α-methylbenzyl) phenol, 2,2′-methylenebis (4
-Ethyl-6-t-butylphenol), 2,2'-methylenebis (4-methyl-6-t-butylphenol), 4,4'-butylidenebis (3-methyl-6-t
-Butylphenol), 4,4'-thiobis (3-methyl-6-t-butylphenol), 2,5-di-t-butylhydroquinone, 2,5-di-t-amylhydroquinone, 2,6-di- t-butyl-p-cresol,
2,4,6-tri-t-butylphenol, styrenated phenol, 4-hydroxy-methyl-2,6-di-
t-butylphenol, 2,5-di-t-butyl-hydroquinone, cyclohexylphenol, butylhydroxyanisole, 4,4'-isopropylidenebisphenol, 1,1-bis- (4-hydroxy-phenyl) cyclohexane, 4,4'-methylene-bis (2,
6-di-t-butylphenol), 2,6-bis (2 ′
-Hydroxy-3'-t-butyl-5'-methylbenzyl) 4-methyl-phenol, 1,1,3-tris (2-methyl-4-hydroxy-5-t-butyl-phenyl) butane, tris ( 3,5-di-t-butyl-4
-Hydroxyphenyl) isocyanurate, tris [β- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl-oxyethyl] isocyanate, 4,4′-thiobis (2-methyl-6-t- Butylphenol) and the like. Among them, particularly preferred is octadecyl-3- (3,5-di-), which has little effect on curability and has good compatibility with a saturated hydrocarbon polymer.
t-butyl-4-hydroxyphenyl) propionate or pentaerythrityl-tetrakis {3- (3,5
-Di-t-butyl-4-hydroxyphenyl) propionate}. Examples of benzotriazole-based compounds include, for example, 2- (5-methyl-2-hydroxyphenyl) benzotriazole and 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl]- 2H-benzotriazole, 2- (3,5-
Di-tert-butyl-2-hydroxyphenyl) benzotriazole, 2- (3-tert-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole,
2- (3,5-di-t-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-
Di-t-amyl-2-hydroxyphenyl) benzotriazole and the like. Among them, 2- (3,5-di-
T-butyl-2-hydroxyphenyl) benzotriazole and 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole are preferable in that the curability is hardly reduced.

Further, various plasticizers and various inorganic fillers can be added to the curable composition of the present invention according to the purpose.

The plasticizer is added in order to improve the fluidity of the present composition. Generally used plasticizers can be used, but the saturated hydrocarbon polymer used in the present invention can be used. Those having good compatibility are preferred. Specific examples of the plasticizer include, for example, polybutene, hydrogenated polybutene, α-
Methylstyrene oligomer, liquid polybutadiene, hydrogenated liquid polybutadiene, paraffin oil, naphthenic oil, atactic polypropylene and the like, among which hydrogenated polybutene preferably containing no unsaturated bond, hydrogenated liquid polybutadiene, paraffin oil, Hydrocarbon compounds such as naphthenic oil and atactic polypropylene are preferred.

Further, the curable composition of the present invention includes:
If necessary, other fillers, ultraviolet absorbers, pigments, surfactants, and the like, and an adhesiveness-imparting agent for imparting adhesiveness to the curable composition can be appropriately added. Specific examples of the filler include silica, alumina, calcium carbonate, titanium oxide, zinc white, barium sulfate, clay, inorganic compounds such as talc, polypropylene, polyethylene,
Organic fillers such as polyacrylic acid esters can be used. Further, as an adhesion-imparting agent, various silane coupling agents that do not inactivate the catalyst, for example, specifically, epoxy-based, olefin-based, methacryl-based, ester-based,
A tertiary amine silane coupling agent is exemplified.

[0034] The method of using the composition of the present invention is not particularly limited, but may be a method using a mold molded or extruded, or a method using a bead, or spray spraying, roll coating or the like. A method in which the composition is sometimes discharged onto a base material and cured for use.

The composition of the present invention can be used as a sealing material, a gasket material, an adhesive, a sealing material / potting material, various coating materials, a vibration-proof material, etc., having low moisture permeability, low moisture absorption, low gas permeability, heat resistance. It can be expected to be used in a wide range of application fields, utilizing its weather resistance, electrical insulation, and vibration absorption. Although there are no particular restrictions on specific applications, for example, gasket seal materials used for capacitors, lithium batteries, fuel cells, batteries, chemical plants, engines, fuel tanks, etc., architectural seals, rooftop waterproofing and solar cell seals Gasket materials for outdoor use such as stoppers, pipes, boxes for sealing electric circuits, lids for industrial cans, food cans, bottles, etc., packing used for high-performance ink materials such as ink cartridges, and the surface of electronic circuits Protective coats, card materials such as IC cards, surface coating materials for packing materials such as aluminum that require chemical resistance such as fuel cells, sound insulation, vibration-proof sheet materials, roll materials for machinery and electrical equipment, hydrogen, Examples thereof include a pipe through which a gas such as oxygen passes and a sealing material for a joint portion.

[0036]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. Example 1 An allyl group-terminated polyisobutylene having a molecular weight of about 10,000 as component (A) synthesized by the method described in JP-A-63-105005 (EP20, manufactured by Kanebuchi Chemical Industry Co., Ltd.)
OA) 100 g and modified hydrogen polysiloxane (B) component (manufactured by Kaneka Chemical Co., Ltd., CR10)
0) was mixed in an amount of 5 g, and as a component (D), bis (1, 2, 2,
1 g of 2,6,6-pentamethyl-4-piperidyl) sebacate (trade name LS-765, manufactured by Sankyo Co., Ltd.), 1 g of Irganox 1010 (manufactured by Ciba-Geigy), and Sumisorb 400 (manufactured by Sumitomo Chemical Co., Ltd.) 1 g was mixed well by hand. To this mixture was added 55% of a platinum vinyl siloxane complex catalyst (3 wt% xylene solution) as component (C).
μL and 37 μL of dimethyl malate (manufactured by Wako Pure Chemical Industries, Ltd.) as a curing inhibitor were added and mixed. After defoaming this composition, it is poured into a mold and heated at 150 ° C./3
Cured in 0 minutes. The cured product was punched out with a JIS No. 2 (1/3) dumbbell, and the tensile properties were measured. 100 ° C
The curing time was also measured.

Further, the JIS No. 2 (1/3) dumbbell was placed in an oven at 150 ° C., and the tensile properties after heat resistance were evaluated. Table 1 shows the evaluation results. Example 2 The antioxidant was 1 octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate (trade name: MARKAO-50, manufactured by Adeka Argus Co., Ltd.).
The same operation as in Example 1 was performed except that g was added.
Table 1 shows the results. Comparative Example 1 The component (D) was bis (2,2,2,6-tetramethyl-4).
-Piperidyl) sebacate (trade name: LS-770, manufactured by Sankyo Co., Ltd.) was used, and the same operation as in Example 1 was performed. Table 1 shows the results. Comparative Example 2 The same operation as in Example 1 was performed except that the component (D), Irganox 1010, and Sumisorb 400 were not added. Table 1 shows the results. Comparative Example 3 The same operation as in Comparative Example 1 was performed except that Irganox 1010 was not added. Table 1 shows the results.

[0038]

[Table 1] As can be seen from Table 1, by using a hindered amine-based stabilizer in which an alkyl group is bonded to a nitrogen atom in the piperidine skeleton, curability and initial mechanical properties are not significantly reduced, and heat resistance can be improved. Was found.

[0039]

According to the present invention, there is provided an addition-type curing system using an organic polymer such as a saturated hydrocarbon polymer, in which the heat resistance of a cured product after curing is improved, and furthermore, a curing which gives good mechanical properties. The present invention relates to an acidic composition.

Claims (6)

[Claims] 1. A curable composition comprising the following components (A), (B), (C) and (D) as essential components: (A) at least one alkenyl capable of hydrosilylation in a molecule An organic polymer containing a group, (B) a curing agent containing at least two hydrosilyl groups in a molecule,
(C) a hydrosilylation catalyst, and (D) a hindered amine-based stabilizer in which an alkyl group is bonded to a nitrogen atom in a piperidine skeleton. 2. The curable composition according to claim 1, wherein the organic polymer as the component (A) is a saturated hydrocarbon polymer. 3. The curable composition according to claim 2, wherein the saturated hydrocarbon polymer as the component (A) is a polyisobutylene polymer. 4. The curable composition according to claim 3, wherein the total amount of the repeating units derived from isobutylene is 50% by weight or more. 5. The saturated hydrocarbon polymer as the component (A) has an alkenyl group at a terminal.
The curable composition according to any one of the above. 6. The curable composition according to claim 1, wherein the curing agent (B) is a polyorganohydrogenpolysiloxane containing at least two hydrosilyl groups in a molecule.