JP2995310B2 - Curable composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a reactive silicon group (a silicon atom-containing group containing a silicon atom to which a hydroxyl group or a hydrolyzable group is bonded and capable of forming a siloxane bond; the same applies hereinafter). The present invention relates to a novel curable composition containing an oxypropylene polymer.

[0002]

2. Description of the Related Art An oxypropylene polymer having a reactive silicon group can be a liquid polymer and is cured at room temperature by moisture or the like to produce a rubber-like elastic cured product. For this reason, it is used as an elastic sealant adhesive for buildings and the like.

[0003] It is desirable that these have an appropriate viscosity at the time of compounding and at the time of use, and furthermore, in order to exert the mechanical properties of the cured product, particularly the rubber elasticity which is rich in flexibility,
It is desirable to have a constant molecular weight.

[0004] Many proposals have been made on a method for producing an organic polymer having a reactive silicon group in the molecule. For example, the main chain produced and sold by Kanegafuchi Chemical Industry Co., Ltd. has an oxypropylene polymer. There is an organic polymer (trade name; MS polymer) in which a methoxysilyl group is bonded to a terminal at a coalescence.

However, conventionally, it has been difficult to produce a high-molecular-weight oxypropylene polymer having a narrow molecular weight distribution (Mw / Mn is small by GPC).
Wide molecular weight distribution (Mw / Mn by GPC is large)
Only the polymer was used.

Recently, it has been reported that an oxypropylene polymer having a narrow molecular weight distribution can be obtained. A polymer in which a oxypropylene polymer having a narrow molecular weight distribution is used as a main chain and a reactive silicon group is introduced at a terminal has a low viscosity before curing.

The inventors of the present invention have determined that the tear strength of a curable composition containing two or more oxypropylene polymers having different Mn after curing is determined from the tear strength of a cured product of a single polymer. The inventors have found that the value is greatly improved from the estimated value, and have reached the present invention.

[0008]

The curable composition of the present invention has a polymerizable main chain consisting essentially of

[0009]

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An oxypropylene polymer having at least one reactive silicon group, comprising a repeating unit represented by the formula: Mw / Mn (the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn); (Similar) is 1.6 or less, the curable composition containing an oxypropylene polymer having a Mn of 2 or more.

It is preferable to contain two or more oxypropylene polymers whose Mn differs by 1,000 or more.

The reactive silicon group referred to in the present invention is not particularly limited, but typical ones include, for example,
A group represented by the following general formula [Formula 3] is exemplified.

[0013]

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[Wherein R ¹ and R ² each represent 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 ′) ₃ S
shows a triorganosiloxy group represented by Io-, ^{R 1}
Or, when two or more R ² are present, they may be the same or different. Here, R 'is a monovalent hydrocarbon group having 1 to 20 carbon atoms, and the three R's may be the same or different. X represents a hydroxyl group or a hydrolyzable group, and when two or more Xs are present, they may be the same or different. a represents 0, 1, 2 or 3, and b represents 0, 1 or 2. In addition, m

[0015]

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In the formula, b may be different. m is 0
Represents an integer of ~ 19. However, it is assumed that a + Σb ≧ 1 is satisfied. The hydrolyzable group represented by X is not particularly limited, and may be any conventionally known hydrolyzable group. Specific examples include a hydrogen atom, 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, and an alkenyloxy group. Of these, a hydrogen atom, 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, but from the viewpoint of gentle hydrolysis and easy handling. An alkoxy group such as a methoxy group is particularly preferred.

This hydrolyzable group or hydroxyl group can be bonded to one to three silicon atoms, and (a + Δb) is 1
-5 is preferred. When two or more hydrolyzable groups or hydroxyl groups are present in the reactive silicon group, they may be the same or different.

The reactive silicon group may contain one silicon atom or two or more silicon atoms. In the case of a reactive silicon group in which silicon atoms are linked by a siloxane bond or the like, 20 silicon atoms are required. There may be degrees.

The reactive silicon group represented by the following general formula [Chemical Formula 5] is preferable from the viewpoint of easy availability.

[0020]

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(Wherein R ² , X and a are the same as those described above). Specific examples of R ¹ and R ² in the above general formula [Chemical Formula 3] include, for example, alkyl groups such as methyl group and ethyl group. Group, cycloalkyl group such as cyclohexyl group, aryl group such as phenyl group, aralkyl group such as benzyl group, and R ′ is methyl group or phenyl group (R ′)
Etc. triorganosiloxy group represented by ₃ SiO- and the like. As R ¹ , R ² and R ′, a methyl group is particularly preferred.

It is preferable that at least one, preferably 1.1 to 5 reactive silicon groups are present in one molecule of the oxypropylene polymer. When the number of reactive silicon groups contained in one molecule of the polymer is less than one, the curability becomes insufficient,
It becomes difficult to exhibit good rubber-like elastic behavior.

The reactive silicon group may be present at the terminal of the molecular chain of the oxypropylene polymer or may be present therein. When the reactive silicon group is present at the terminal of the molecular chain, the effective network chain amount of the oxypropylene polymer component contained in the finally formed cured product increases, so that high strength, high elongation, and low elastic modulus are obtained. The resulting rubber-like cured product is easily obtained.

The oxypropylene polymer constituting the polymerization main chain in the polymer of the present invention is

[0025]

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And a repeating unit represented by the formula: The oxypropylene polymer may be linear or branched, or a mixture thereof. Further, other monomer units and the like may be contained, but the monomer units represented by [Chemical Formula 6] may be present in the polymer in an amount of 50% by weight or more, preferably 80% by weight or more. preferable.

The oxypropylene polymer having a reactive silicon group in the present invention is preferably obtained by introducing a reactive silicon group into an oxypropylene polymer having a functional group.

The oxypropylene polymer having a high molecular weight and a narrow molecular weight distribution and having a functional group can be obtained by a usual polymerization method of oxypropylene (anionic polymerization method using caustic alkali) or a chain extension reaction method using this polymer as a raw material. Although it is extremely difficult to obtain, Japanese Patent Application Laid-Open Nos. 61-197632 and 61-215622, which are special polymerization methods,
JP-A-61-215623, JP-A-61-21863
No. 2, JP-B-46-27250 and JP-B-59-1
No. 5,336, and the like.

The introduction of the reactive silicon group may be performed by a known method. That is, for example, the following method is used.

(1) An oxypropylene polymer having a functional group such as a hydroxyl group at the terminal is reacted with an organic compound having an active group and an unsaturated group which are reactive with the functional group. Hydrosilylation is performed by reacting a hydrosilane having a hydrolyzable group on the reaction product.

(2) An oxypropylene polymer having a functional group such as a hydroxyl group, an epoxy group or an isocyanate group (hereinafter referred to as a Y functional group) at a terminal thereof is reacted with a functional group (hereinafter referred to as a Y functional group) , Y ′ functional group) and a compound having a reactive silicon group.

Examples of the silicon compound having a Y 'functional group include γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, and γ-aminopropyltriethoxysilane. Amino group-containing silanes such as γ-
Mercapto group-containing silanes such as mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane; γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, etc. Epoxy silanes; vinyl-type unsaturated group-containing silanes such as vinyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-acryloyloxypropylmethyldimethoxysilane; and γ-chloropropyltrimethoxysilane Silanes containing chlorine atoms;
γ-isocyanatopropyltriethoxysilane, γ-
Isocyanate-containing silanes such as isocyanatepropylmethyldimethoxysilane and the like; hydrosilanes such as methyldimethoxysilane, trimethoxysilane, methyldiethoxysilane and the like can be specifically exemplified, but are not limited thereto. Absent.

Of the above methods, the method (1) or the method (2) of reacting a polymer having a terminal hydroxyl group with a compound having an isocyanate group and a reactive silicon group is preferable.

The reactive silicon group-containing oxypropylene polymer usable in the present invention has an Mn of 3,000 to 5
5,000, preferably 5,000 to 30,
More preferably, 000.

The reactive silicon group-containing oxypropylene polymer has an Mw / Mn of 1.6 or less and a narrow molecular weight distribution (high monodispersity). The value of Mw / Mn is preferably 1.5 or less, more preferably 1.4 or less. A polymer having a narrow molecular weight distribution despite its large number average molecular weight has low viscosity before curing and is easy to handle.

Although the molecular weight distribution can be measured by various methods, it is usually determined by gel permeation chromatography (GPC).
Measurement by the method is common.

To obtain the curable composition of the present invention, a method of mixing two or more oxypropylene polymers having different Mn after the introduction of a reactive silicon group, or a method of mixing two types having a functional group at a terminal. There is a method in which the above oxypropylene polymer is preliminarily mixed, and thereafter, a reactive silicon group is introduced into the functional group, but the method is not limited thereto.

The two or more reactive silicon group-containing oxypropylene polymers used in the present invention have different Mn, and the two or more oxypropylene polymers differing in Mn by 1,000 or more are used. It is more preferable to use two or more kinds that differ by 3,000 or more. For example, when the curable composition of the present invention is a three-component system, the composition having Mn of 12,000 and the composition having Mn of 15,000
00 and 20,000.

The tear strength of the cured product of the curable composition of the present invention is greatly improved as compared with the cured product of each homopolymer. Further, in the present invention, it is possible to set the modulus, elongation, and strength of the cured product within a certain range by changing the mixing ratio of two or more reactive silicon group-containing oxypropylene polymers to be used. Become. further,
It becomes easy to set the viscosity of the composition to a range suitable for work.

In particular, the effect of the tear strength is not remarkable when the difference between the molecular weights of the mixed components is small, but is remarkable when the difference is large.

The mixing ratio of each oxypropylene polymer in the curable composition of the present invention is not particularly limited. For example, when two kinds (A component + B component) are used, A
Part by weight of component: 95: 5 to 5:95 by weight of component B
And more preferably 90:10 to 10:90. In the case of three or more kinds, each component in the whole polymer may be in the range of 10 to 90% by weight.

In curing the composition of the present invention, a curing catalyst may or may not be used. When a curing catalyst is used, conventionally known curing catalysts can be widely used. Specific examples thereof include titanates such as tetrabutyl titanate and tetrapropyl titanate; tin carboxylate salts such as dibutyltin dilaurate, dibutyltin maleate, dibutyltin diacetate, tin octylate, tin naphthenate; dibutyltin oxide and phthalate Dibutyltin diacetylacetonate; organoaluminum compounds such as aluminum trisacetylacetonate, aluminum trisethylacetoacetate, diisopropoxyaluminum ethylacetoacetate; chelates such as zirconium tetraacetylacetonate and titanium tetraacetylacetonate Compounds; lead octylate; butylamine, octylamine, laurylamine, dibutylamine, monoethanolamine , Diethanolamine, triethanolamine, diethylenetriamine, triethylenetetramine, oleylamine, cyclohexylamine, benzylamine, diethylaminopropylamine, xylylenediamine, triethylenediamine, guanidine, diphenylguanidine, 2,4,6-tris (dimethylaminomethyl) Phenol, morpholine, N
Amine compounds such as -methylmorpholine, 2-ethyl-4-methylimidazole, 1,8-diazabicyclo (5.4.0) undecene-7 (DBU), or salts of these amine compounds with carboxylic acids and the like; Low molecular weight polyamide resin obtained from excess polyamine and polybasic acid; reaction product of excess polyamine and epoxy compound; γ-aminopropyltrimethoxysilane, N- (β
Silanol condensation catalysts such as silane coupling agents having an amino group such as -aminoethyl) aminopropylmethyldimethoxysilane; and other known silanol condensation catalysts such as other acidic catalysts and basic catalysts.
These catalysts may be used alone or in combination of two or more.

These curing catalysts are used in an amount of 100 parts by weight of a reactive silicon group-containing oxypropylene polymer (hereinafter referred to as "reactive silicon group-containing oxypropylene polymer")
About 0.1 to about 20 parts, more preferably about 1 to about 10 parts. If the amount of the curing catalyst used is too small relative to the reactive silicon group-containing oxypropylene polymer, the curing rate becomes slow, and the curing reaction does not easily proceed sufficiently. On the other hand, if the amount of the curing catalyst is too large relative to the reactive silicon group-containing oxypropylene polymer, local heat generation or foaming occurs during curing, and it is difficult to obtain a good cured product, which is not preferable.

The reactive silicon group-containing oxypropylene polymer can be modified by incorporating various fillers. As fillers, reinforcing fillers such as fume silica, precipitated silica, silicic anhydride, hydrous silicic acid and carbon black; calcium carbonate, magnesium carbonate, diatomaceous earth, calcined clay, clay, talc, titanium oxide, bentonite, organic Fillers such as bentonite, ferric oxide, zinc oxide, activated zinc white, hydrogenated castor oil and shirasu balloon; fibrous fillers such as asbestos, glass fibers and filaments.

When a high-strength cured composition is desired to be obtained with these fillers, mainly fumed silica, precipitated silica, silicic anhydride, hydrous silicic acid, carbon black, surface-treated fine calcium carbonate, calcined clay, clay, If a filler selected from active zinc white and the like is used in an amount of 1 to 100 parts based on 100 parts of the reactive silicon group-containing oxypropylene polymer, preferable results can be obtained. In addition, when it is desired to obtain a cured composition having low strength and large elongation, a filler selected mainly from titanium oxide, calcium carbonate, magnesium carbonate, talc, ferric oxide, zinc oxide, and shirasu balloon, etc. Is used in the range of 5 to 200 parts with respect to 100 parts of the reactive silicon group-containing oxypropylene polymer, a preferable result can be obtained. Of course, these fillers may be used alone or in combination of two or more. It is preferable that many fillers can be used by lowering the viscosity.

In the curable composition of the present invention, it is more effective to use a plasticizer in combination with a filler, since the elongation of the cured product can be increased or a large amount of filler can be mixed. As this plasticizer, dioctyl phthalate,
Phthalates such as dibutyl phthalate and butyl benzyl phthalate; aliphatic dibasic esters such as dioctyl adipate, isodecyl succinate and dibutyl sebacate; glycol esters such as diethylene glycol dibenzoate and pentaerythritol; Aliphatic esters such as butyl oleate and methyl acetyl ricinoleate; phosphates such as tricresyl phosphate, trioctyl phosphate and octyl diphenyl phosphate; epoxy plastics such as epoxidized soybean oil and epoxy benzyl stearate; Polyester plasticizers such as polyesters of dibasic acid and dihydric alcohol; Polyethers such as polypropylene glycol and its derivatives; Poly-α-methylstyrene, polystyrene Polystyrenes such emissions; polybutadiene, butadiene - acrylonitrile copolymer, polychloroprene, polyisoprene, polybutene, can be used in any form of plasticizers alone or a mixture of two or more of such chlorinated paraffins. The amount of the plasticizer is 1 to 10 based on 100 parts of the reactive silicon group-containing oxypropylene polymer.
When used in the range of 0 parts, a preferable result is obtained.

The method for preparing the curable composition of the present invention is not particularly limited. For example, the above-mentioned components are blended and kneaded at room temperature or under heat using a mixer, roll or kneader, or a suitable solvent is added. Conventional methods such as dissolving and mixing the components using a small amount can be employed. Also, by appropriately combining these components, a one-pack or two-pack composition can be prepared and used.

When exposed to the atmosphere, the curable composition of the present invention forms a three-dimensional network by the action of moisture and cures into a solid having rubber-like elasticity.

When using the curable composition of the present invention, if necessary, an adhesion improver, a physical property modifier,
Various additives such as a storage stability improver, a lubricant, a pigment, and a foaming agent can be appropriately added.

The curable composition of the present invention is particularly useful as an elastic sealant and can be used as a sealant for buildings, ships, automobiles, roads and the like. Further, since it can adhere to a wide range of substrates such as glass, porcelain, wood, metal, and resin moldings alone or with the aid of a primer, it can be used as various types of sealing compositions and adhesive compositions. . Further, it is also useful as a food packaging material, a cast rubber material, a molding material, and a paint.

[0051]

The cured product of the curable composition of the present invention has excellent tear strength.

[0052]

EXAMPLES In order to further clarify the present invention, examples will be given below.

Synthesis Example 1 A 1.5-liter pressure-resistant glass reaction vessel was charged with a molecular weight of 15.0
00 polyoxypropylene triol (Mw / Mn =
1.38 g (0.081 equivalent) of 1.38 and a viscosity of 89 poise were charged and the atmosphere was changed to a nitrogen atmosphere.

At 137 ° C., 19.1 g of a 28% methanol solution of sodium methoxide (0.099 g) was added through a dropping funnel.
Was added dropwise and reacted for 5 hours, followed by devolatilization under reduced pressure.
Return under nitrogen atmosphere, 9.0 g of allyl chloride (0.118
Was added dropwise and reacted for 1.5 hours, and then 5.6 g of a 28% methanol solution of sodium methoxide (0.5 g) was added.
029 equiv) and 2.7 g of allyl chloride (0.035 equiv)
Allylation was carried out using.

After dissolving the reaction product in hexane and adsorbing it with aluminum silicate, the hexane was removed under reduced pressure to obtain 311 g of a yellow transparent polymer (viscosity: 68 poise).

270 g (0.065 equivalent) of this polymer
Was charged into a pressure-resistant glass reaction vessel, and was set to a nitrogen atmosphere.
Catalyst solution of chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O 2
After adding 0.075 ml of a solution in which 5 g was dissolved in 500 g of isopropyl alcohol, the mixture was stirred for 30 minutes. 6.24 g (0.059 equivalents) of dimethoxymethylsilane was added from a dropping funnel, reacted at 90 ° C. for 4 hours, and then devolatilized to obtain 260 g of a yellow transparent polymer (Mn = 1.8 × 10 4).
⁴ , Mw / Mn = 1.5; GPC).

Synthesis Example 2 A 1.5-liter pressure-resistant glass reaction vessel was charged with a molecular weight of 6,000.
0 polyoxypropylene triol (Mw / Mn =
1.1, viscosity 11 poise) 381 g (0.183 equivalent)
Was charged to make a nitrogen atmosphere.

At 137 ° C., 42.5 g (0.220%) of a 28% methanol solution of sodium methoxide was added through a dropping funnel.
Was added dropwise and reacted for 5 hours, followed by devolatilization under reduced pressure.
Return under nitrogen atmosphere, 28.5 g of allyl chloride (0.37
2 eq.) And allowed to react for 1.5 hours, and then 16.9 g of a 28% methanol solution of sodium methoxide.
(0.088 equivalents) and 7.9 g of allyl chloride (0.103
).

This reaction product was dissolved in hexane and subjected to adsorption treatment with aluminum silicate, and then hexane was removed under reduced pressure to obtain 313 g of a yellow transparent polymer (viscosity: 10 poise).

270 g of this polymer (0.148 equivalent)
Was charged into a pressure-resistant glass reaction vessel, and was set to a nitrogen atmosphere.
Catalyst solution of chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O 2
After adding 0.075 ml of a solution in which 5 g was dissolved in 500 g of isopropyl alcohol, the mixture was stirred for 30 minutes. 14.06 g (0.132 equivalents) of dimethoxymethylsilane was added from a dropping funnel, reacted at 90 ° C. for 4 hours, and then devolatilized to obtain 264 g of a yellow transparent polymer (Mn = 7.8 × 1).
O ³ , Mw / Mn = 1.1; GPC).

Synthesis Example 3 A 1.5-liter pressure-resistant glass reaction vessel was charged with a molecular weight of 9000
0 polyoxypropylene glycol (Mw / Mn =
1.16, viscosity of 48 poise), 330 g (0.067 equivalents) were charged, and the atmosphere was changed to nitrogen.

At 130 ° C., 14.1 g (0.073) of a 28% methanol solution of sodium methoxide was added through a dropping funnel.
Was added dropwise and reacted for 5 hours, followed by devolatilization under reduced pressure.
6.7 g of allyl chloride (0.087
Was added dropwise and reacted for 1.5 hours, and then 4.0 g of a 28% methanol solution of sodium methoxide (0.4 g).
021 equivalents) and 1.9 g of allyl chloride (0.025 equivalents)
Allylation was carried out using.

This reaction product was dissolved in hexane and treated by adsorption with aluminum silicate, and then hexane was removed under reduced pressure to obtain 290 g of a yellow transparent polymer (viscosity: 38 poise).

210 g of this polymer (0.040 equivalent)
Was charged into a pressure-resistant glass reaction vessel, and was set to a nitrogen atmosphere.
Catalyst solution of chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O 2
0.046 ml of a solution obtained by dissolving 5 g in 500 g of isopropyl alcohol) was added thereto, followed by stirring for 30 minutes. 6.0 g (0.057 equivalents) of dimethoxymethylsilane was added from a dropping funnel and reacted at 90 ° C. for 4 hours. After devolatilization, 200 g of a yellow transparent polymer (Mn = 12,000,
Mw / Mn = 1.3; GPC) was obtained.

Example 1 To 100 parts of a mixture of 50 parts of the polymer obtained in Synthesis Example 1 and 50 parts of the polymer obtained in Synthesis Example 2, 50 parts of dioctyl phthalate, calcium carbonate (CCR manufactured by Shiraishi Industry Co., Ltd.) ) 120 parts, titanium dioxide (rutile type titanium oxide R-820 manufactured by Ishihara Sangyo Co., Ltd.) 20 parts, vinyltrimethoxysilane 2 parts, aminosilane compound (A-1120 manufactured by Nippon Unicar Co., Ltd.) 3 parts, thixotropy imparting 2 parts of an agent (D-6500 manufactured by Kusumoto Kasei Co., Ltd.) and a curing accelerator (Neostan U-220 manufactured by Nitto Kasei Co., Ltd.)
Add 2 parts and 2 parts of anti-aging agent, knead and mix, JIS
A type 5 H-type sample specified in A 5758 and a sheet-shaped cured sample having a thickness of 3 mm were prepared, and a dumbbell for a tear test (JIS A) was prepared from the sheet-shaped cured sample.
Type).

Example 2 In the same manner as in Example 1, 50 parts of the mixture of 50 parts of the polymer obtained in Synthesis Example 3 and 50 parts of the polymer obtained in Synthesis Example 2 were treated with 50 parts of dioctyl phthalate and calcium carbonate ( 120 parts of CCR (Shiroishi Industry Co., Ltd.), titanium dioxide (rutile type titanium oxide R-82 manufactured by Ishihara Sangyo Co., Ltd.)
0) 20 parts, vinyltrimethoxysilane 2 parts, aminosilane compound (A-1120 manufactured by Nippon Unicar Co., Ltd.)
3 parts, thixotropic agent (D-650 manufactured by Kusumoto Kasei Co., Ltd.)
0) 2 parts, 2 parts of a curing accelerator (Neostan U-220, manufactured by Nitto Kasei Co., Ltd.) and 2 parts of an antioxidant were added and kneaded. A sheet-shaped cured sample having a thickness of 3 mm was prepared, and a dumbbell (JIS A type) for a tear test was prepared from the sheet-shaped cured sample.

Comparative Examples 1 to 3 For 100 parts of each polymer obtained in Synthetic Examples 1 to 3, 50 parts of dioctyl phthalate, 120 parts of calcium carbonate (CCR manufactured by Shiroishi Kogyo KK) and 120 parts of Titanium (Rutile titanium oxide R-8 manufactured by Ishihara Sangyo Co., Ltd.)
20) 20 parts, vinyltrimethoxysilane 2 parts, aminosilane compound (A-112 manufactured by Nippon Unicar Co., Ltd.)
0) 3 parts, thixotropic agent (D-6 manufactured by Kusumoto Kasei Co., Ltd.)
500), 2 parts of a curing accelerator (Neostan U-220, manufactured by Nitto Kasei Co., Ltd.), and 2 parts of an antioxidant, and kneaded. A sheet-shaped cured sample having a thickness of 3 mm was prepared, and a dumbbell (JIS A type) for a tear test was prepared from the sheet-shaped cured sample. (The polymer of Synthesis Example 1 corresponds to Comparative Example 1, and the polymer of Synthesis Example 2 is Comparative Example 2.
And the polymer of Synthesis Example 3 corresponds to Comparative Example 3. ).

Using each of the dumbbells for the tear test of Examples 1 and 2 and Comparative Examples 1 to 3, a tear test was performed to measure the tear strength. The results are shown in [Table 1].

Using each of the H-type samples of Examples 1 and 2 and Comparative Examples 1 to 3, a tensile test was performed to measure the breaking strength (TB) and the elongation at break (EB). The results are also shown in [Table 1].

[0070]

[Table 1]

As is clear from Table 1, the tear strength of the cured product of Example 1 is higher than the value estimated from the tear strength of Comparative Example 1 or Comparative Example 2.

The tear strength of the cured product of Example 2 was as follows:
It is higher than the value estimated from the tear strength of Comparative Example 2 or Comparative Example 3.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C08L 71/00-71/14 C08G 65/00-65/48

Claims (2)

(57) [Claims] 1. The polymer backbone essentially comprises: ## STR1 ## A oxypropylene polymer comprising at least one silicon atom-containing group containing a silicon atom bonded to a hydroxyl group or a hydrolyzable group, and having an Mw / Mn of 1.6 or less. A curable composition comprising two or more of the above oxypropylene polymers having different Mn. 2. The curable composition according to claim 1, wherein the curable composition contains two or more oxypropylene polymers whose Mn differs by 1,000 or more.