JP3087138B2 - Curable composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable composition and, more particularly, to a silicon atom-containing group containing a silicon atom having a hydroxyl group or a hydrolyzable group bonded thereto, which is capable of forming a siloxane bond (hereinafter referred to as "a"). Oxypropylene polymer containing a "reactive silicon group"), a specific silicon compound,
And a novel curable composition containing a curing catalyst.

[0002]

BACKGROUND OF THE INVENTION An oxypropylene polymer containing 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 cured product. For this reason, it is used as an elastic sealant or adhesive for buildings.

[0003] It is desirable that these materials have an appropriate curing speed upon curing, and that the rubber-like cured product has a non-adhesive surface, a large elongation property as a tensile physical property, and a rubber elasticity rich in flexibility. Is desirable.

Many proposals have been made for a method for producing an organic polymer having a reactive silicon group in the molecule.
Some are already industrially produced. For example, an organic polymer (trade name: MS polymer) having a main chain of polyoxypropylene and a methoxysilyl group bonded to a terminal, which is manufactured and sold by Kanegafuchi Chemical Industry Co., Ltd.

[0005] This organic polymer has an appropriate curing speed at the time of curing. However, with respect to the elongation of the cured product and the residual tack (stickiness) on the surface, there are certain kinds of composition and use conditions. May not be sufficient, and improvement has been desired depending on the application.

On the other hand, the present inventors have improved the tensile properties (increased elongation) and improved the residual tack (decreased tackiness).
For this reason, a method of adding or reacting a specific silicon compound to the organic polymer has already been proposed (see JP-A-64-9268).

Although the above-mentioned drawbacks in elongation properties and tackiness could be eliminated, the use of the silicon compound tended to slow down the internal curing speed (deep curing speed). Further studied and, as a result, reached the present invention. That is, if a reactive silicon group-containing oxypropylene polymer having a narrow molecular weight distribution and a high molecular weight and a curing catalyst are used, even when the above-mentioned specific silicon compound is used in combination, an appropriate curing speed during curing does not decrease ( While maintaining), and improvement of tensile properties (high elongation) and improvement of residual tack (low adhesion)
Was found to be possible.

[0008]

The curable composition of the present invention comprises (A) a polymerizable main chain comprising:

[0009]

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An oxypropylene polymer containing a repeating unit represented by the formula (1) and having at least one reactive silicon group, wherein Mw / Mn (weight average molecular weight / number average molecular weight) is 1.6 or less and number average molecular weight (Mn) is 6,000
The oxypropylene polymer as described above, (B)

[0011]

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(Wherein R is the same or different and is a substituted or unsubstituted monovalent hydrocarbon group or hydrogen atom), a silicon compound which produces R ₃ SiOH by hydrolysis, and (C) It contains a curing catalyst.

The reactive silicon group contained in the oxypropylene polymer of the component (A) used in the present invention is not particularly limited. , [Chemical formula 7].

[0014]

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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

[0016]

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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. Specifically, for example, 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,
An alkenyloxy group and the like can be mentioned. 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. Particularly preferred.

This hydrolyzable group or hydrogen 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 hydrogen groups are present in the reactive silicon group, they may be the same or different.

The reactive silicon group may have 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 [Formula 9] is preferable from the viewpoint of easy availability.

[0021]

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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 [Formula 7] include, for example, methyl group, ethyl group and the like. An alkyl group, a cycloalkyl group such as a cyclohexyl group, an aryl group such as a phenyl group, an aralkyl group such as a benzyl group, and R ′ being a methyl group or a 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 be 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 1, the curability becomes insufficient,
It becomes difficult to exhibit good rubber elasticity behavior.

The reactive silicon group may be present at the terminal of the molecular chain of the oxypropylene polymer or may be present inside. 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 it exhibits high elasticity, high elongation and low elastic modulus. It becomes easier to obtain a rubbery cured product.

The oxypropylene polymer constituting the polymerization main chain in the component (A) used in the present invention is:

[0026]

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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 it is preferable that the monomer units represented by the formula [Chemical Formula 10] are present in the polymer in an amount of 50% by weight or more, preferably 80% by weight or more. .

The oxypropylene polymer having a reactive silicon group serving as the component (A) of 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, a special polymerization method
1-1197631, JP-A-61-215622, JP-A-61-215623, JP-A-61-218632
No., JP-B-46-27250 and JP-B-59-153
No. 36 or the like.
When a reactive silicon group is introduced, the molecular weight distribution tends to be broader than that of the polymer before the introduction, so that the molecular weight distribution of the polymer before the introduction is preferably as narrow as possible.

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, a functional group having reactivity with the Y functional group (Hereinafter referred to as Y 'functional group) and a compound having a reactive silicon group.

Examples of the silicon compound having the Y 'functional group include γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, 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. Epoxysilanes; 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 isocyanate propyl methyl dimethoxy silane; hydrosilanes such as methyl dimethoxy silane, trimethoxy silane, methyl diethoxy silane 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.

As the number average molecular weight (Mn) of the reactive silicon group-containing oxypropylene polymer, those having a number average molecular weight (Mn) of 6,000 or more can be effectively used.
0000, more preferably 7,000-30,000
It is. Furthermore, in this oxypropylene polymer, the ratio of the weight average molecular weight to the number average molecular weight (Mw / M
n) is 1.6 or less, and the molecular weight distribution is extremely narrow (monodispersity is large). The value of Mw / Mn is preferably 1.5
Or less, more preferably 1.4 or less. The molecular weight distribution can be measured by various methods, but is generally measured by gel permeation chromatography (GPC). Since the molecular weight distribution is narrow in spite of the large number average molecular weight, the composition of the present invention exhibits appropriate curing characteristics at the time of curing and exhibits good rubber-like elastic behavior after curing. In particular, the cured product of the composition of the present invention has a non-adhesive surface and a large elongation property as compared with a composition using an oxypropylene polymer having a reactive silicon group having a wide molecular weight distribution.

The silicon compound used as the component (B) of the present invention includes:

[0037]

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Wherein R is the same or different and is a substituted or unsubstituted monovalent hydrocarbon group ,
It is a silicon compound that produces R ₃ SiOH by hydrolysis.

Among them,

[0040]

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(Wherein R is the same as R in Chemical Formula 11, and Q is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms), or

[0042]

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(Wherein, R is the same as R in [Chemical Formula 11], and Z is a substituted or unsubstituted monovalent organic group having 1 to 20 carbon atoms).

Specific examples are shown below, but the silicon compound as the component (B) is not limited thereto.

The compound represented by the formula [12] includes R
Is a methyl group, an ethyl group, a propyl group, an alkyl group such as a butyl group, an aryl group such as a phenyl group, or a substituted group thereof.

[0046]

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And the like.

Examples of the compound represented by the following formula:

[0049]

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And the like.

In addition, although it does not belong to the above [Formula 12] or [Formula 13],

[0052]

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[0053]

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[0054]

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[0055]

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And the like can also be used.

In the above-mentioned silicon compound (B),

[0058]

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Hexamethyldisilazane is desirable because it is easily available and the synthesis is simple.

The amount of the silicon compound (B) used is not particularly limited, and may be freely changed according to the expected properties of the cured product. 0.1 to 10 parts, preferably 0.5 to 10 parts, per 100 parts of polymer (parts by weight, the same applies hereinafter).
5 parts. Less than 0.1 part has a small effect, and
Use of more than one part is undesirable in terms of a balance between cost and performance due to the use of expensive silicon compounds.

The method of mixing the polymer (A) and the silicon compound (B) of the present invention can be roughly classified into three methods.

One is a method of simply adding the silicon compound (B) to the polymer (A). What is necessary is just to adjust the heating and stirring conditions and the like according to the properties of the silicon compound (B), and to uniformly disperse and dissolve it. In this case, it is not necessary to achieve a completely uniform state, and even if the state is opaque, the object can be sufficiently achieved by dispersing. Also, if necessary,
A dispersibility improver such as a surfactant may be used in combination.

The second method is to mix the compound in a predetermined amount when the final product is used. For example, when used as a two-component sealing material, the compound can be mixed and used as a third component in addition to the base and the curing agent.

The third method involves reacting the compound with an organic polymer in advance. If necessary, a tin-based, titanate-based, acid or basic catalyst may be used in combination with a required amount of water. Is added, and heating and devolatilization under reduced pressure achieves the object.

The curing catalyst used as the component (C) in the present invention is not particularly limited. For example, titanates such as tetrabutyl titanate and tetrapropyl titanate; dibutyltin dilaurate, dibutyltin maleate, dibutyltin diacetate and octylic acid Tin,
Tin carboxylate salts such as tin naphthenate; reaction products of dibutyltin oxide and phthalic acid esters; dibutyltin diacetylacetonate; organic aluminum compounds such as aluminum trisacetylacetonate, aluminum trisethylacetoacetate, diisopropoxyaluminum ethylacetoacetate Chelating compounds such as zirconium tetraacetylacetonate and titanium tetraacetylacetonate; lead octylate; butylamine, octylamine, laurylamine;
Dibutylamine, monoethanolamine, diethanolamine, triethanolamine, diethylenetriamine, triethylenetetramine, oleylamine, cyclohexylamine, benzylamine, diethylaminopropylamine, xylylenediamine, triethylenediamine, guanidine, diphenylguanidine, 2,4,6-
Amine compounds such as tris (dimethylaminomethyl) phenol, morpholine, N-methylmorpholine, 2-ethyl-4-methylimidazole, 1,8-diazabicyclo [5.4.0] undecene-7 (DBU), or these Salts of amine compounds with carboxylic acids and the like; low molecular weight polyamide resins obtained from excess polyamines and polybasic acids; reaction products of excess polyamines with epoxy compounds; γ-aminopropyltrimethoxysilane, N-
A silane coupling agent having an amino group such as (β-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.

The amount of the curing catalyst (C) to be used is preferably about 0.1 to 20 parts, more preferably about 1 to 10 parts, per 100 parts of the reactive silicon group-containing oxypropylene polymer. If the amount of the curing catalyst used is too small relative to the amount of the reactive silicon group-containing oxypropylene polymer, the curing rate may be slow, and the curing reaction may not 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.

In using the curable composition of the present invention, if necessary, a filler, a plasticizer, an adhesion improver, a physical property modifier, a storage stability improver, an antioxidant, an ultraviolet absorber It is possible to appropriately add various additives such as agents, metal deactivators, ozone deterioration inhibitors, light stabilizers, amine-based radical chain inhibitors, phosphorus-based peroxide decomposers, lubricants, pigments, and foaming agents. It is.

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. Use a small amount to dissolve the ingredients,
Ordinary methods such as mixing can be employed. Also, by appropriately combining these components, a one-pack or two-pack composition can be prepared and used.

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

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 an adhesive, a paint, a coating film waterproofing agent, a food packaging material, a cast rubber material, a molding material, and a foam material.

[0071]

According to the curable composition of the present invention, it is possible to improve the tensile properties (high elongation) and the residual tack (low tack) while maintaining an appropriate curing speed.

[0072]

The present invention will be described below with reference to an embodiment, but the present invention is not limited thereto.

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 placed under a nitrogen atmosphere.

At 137 ° C., 19.1 g (0.099 g) 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, 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.

The reaction product was dissolved in hexane and treated by adsorption with aluminum silicate, and then 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 placed under a nitrogen atmosphere. Catalyst solution of chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O
0.075 ml of a solution obtained by dissolving 25 g in 500 g of isopropyl alcohol) was added thereto, followed by stirring 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.

Synthesis Example 2 A polyoxypropylene triol having a number average molecular weight of 15,000 (Mw / Mn = 1.38,
220 g (0.0447 equivalent) of viscosity and 89 g of dibutyltin dilaurate were charged, and 8.45 g (0.0447 equivalent) of γ-isocyanatopropylmethyldimethoxysilane was added dropwise at room temperature under a nitrogen atmosphere.
After the completion of the dropwise addition, the reaction was carried out at 75 ° C. for 1.5 hours. And IR spectrum, after confirming the formation of C = O absorption near disappearance 1730 cm ^-1 of the NCO absorption at about 2280 cm ^-1, the reaction was terminated. 213 g of a colorless and transparent polymer were obtained.

Comparative Synthesis Example 1 420 g of polyoxypropylene glycol having a number-average molecular weight of 3,000 and 80 g of polyoxypropylene triol having a number-average molecular weight of 3,000 were charged in a pressure-resistant glass reaction vessel purged with nitrogen. Sodium hydroxide 40
g was added and reacted at 60 ° C. for 13 hours, and then 19 g of bromochloromethane was reacted at 60 ° C. for 10 hours. (The Mw / Mn of the obtained polymer is 2.1 and the viscosity is 38
5 poise. Then, 15 g of allyl chloride was added and reacted for 36 hours. After the completion of the reaction, the pressure was reduced to remove volatile substances.

The contents were taken out into a beaker and dissolved in hexane. After adsorption treatment with aluminum silicate, hexane was removed under reduced pressure.

500 g of this polymer was charged into a reaction vessel purged with nitrogen, and a catalyst solution of chloroplatinic acid (H ₂ PtCl
The ₆ · _6H 2 O 25g Isopropyl alcohol 500
g), and then added with 12 g of dimethoxymethylsilane and reacted at 80 ° C. for 4 hours. After the completion of the reaction, the pressure was reduced to remove volatile substances, and 550 g of a pale yellow transparent polymer was obtained.

The viscosities of the polymers obtained in Synthesis Example 1, Synthesis Example 2 and Comparative Synthesis Example 1 were measured at 23 ° C. using a B-type viscometer (BM type rotor No. 4, 12 rpm). The number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) of each polymer were analyzed by GPC. GPC
Is a column packed with polystyrene gel (manufactured by Tosoh Corporation) using tetrahydrofuran as a distilling solvent,
Analysis was performed at an oven temperature of 40 ° C. Table 1 shows the results.

[0082]

[Table 1]

Examples 1 and 2 and Comparative Example 1 100 parts of the polymer obtained in Synthesis Example 1, Synthesis Example 2 and Comparative Synthesis Example 1 were mixed with 3 parts of hexamethyldisilazane,
155 parts of colloidal calcium carbonate (manufactured by Shiraishi Kogyo Co., Ltd., trade name “Shirayuka CCR”, average particle size 0.08 μm), 60 parts of dioctyl phthalate, 2 parts of antioxidant, titanium dioxide (trade name of Ishihara Sangyo Co., Ltd. R-820 ") 4
And kneaded well with a triple paint roll, and then 3 parts of tin octylate and 0.5 part of laurylamine were added and kneaded uniformly to obtain a curable composition. Among the obtained compositions, the composition of Example 1 (using the polymer of Synthesis Example 1) and the composition of Example 2 (using the polymer of Synthesis Example 2) were the compositions of Comparative Example 1. The product had a lower viscosity and was easier to handle than the product (using the polymer of Comparative Synthesis Example 1).

Using the obtained composition, the performance in the following physical properties was compared.

(Tensile Properties) A tensile adhesion test was conducted in accordance with JIS A 5758, and the tensile stress at 50% elongation (M50) and elongation at break (EB) were evaluated.

(Curability) A 100 cc beaker was filled up to the upper edge of the beaker, and the cured state after curing at 5 ° C. for 24 hours was evaluated by a finger pressure method.

The evaluation criteria were as follows: 場合 when completely cured to the inside, 若干 when some uncured parts were found inside, but almost completely cured, 多 く: many uncured parts inside The case was evaluated as Δ, and the case where only the surface was hardened and the inside was unhardened was evaluated as x.

(Tackiness) After filling in a 100 cc beaker and curing at 23 ° C. for 24 hours, residual tack (tackiness) on the surface was evaluated by finger touch.

The evaluation criteria were ◎ when there was no tackiness and good, ○ when some tackiness was observed, and x when the surface was sticky.

As a reference example, a composition was obtained in the same manner as in Examples 1 and 2 and Comparative Example 1 except that hexamethyldisilazane was not used, and the same test (tensile adhesion) was performed using this composition. Sex test).

The results are summarized in Table 2.

[0092]

[Table 2]

As is evident from Table 2, the curability of the oxypropylene polymer having a narrow molecular weight distribution is lower than that of the oxypropylene polymer having a narrow molecular weight distribution even when a silicon compound is used. There is almost no decrease, the elongation characteristics of tensile properties are greatly improved, and 50%
It can be seen that despite the low tensile stress during elongation, a good residual tack (surface non-stickiness) is exhibited.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-298525 (JP, A) JP-A-62-151453 (JP, A) JP-A-62-151454 (JP, A) International publication 91/13927 (WO, A1) WO 91/13928 (WO, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 71/00-71/14

Claims (2)

(57) [Claims] (1) The polymerization main chain of (A) is: An oxypropylene polymer containing at least one silicon atom-containing group containing a silicon atom having a hydroxyl group or a hydrolyzable group bonded thereto, wherein Mw / Mn is 1.6 or less and a number average Molecular weight 6,000
An oxypropylene polymer having 0 or more, (B) (Wherein R is the same or different and is substituted or unsubstituted 1
It contains a group represented by valent hydrocarbon group), a silicon compound to produce a R ₃ SiOH by hydrolysis, and (C) curable composition characterized by containing a curing catalyst. 2. The method according to claim 1, wherein the silicon compound as the component (B) is: (Wherein Q is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms), or The curable composition according to claim 1, wherein the compound is a silicon compound represented by the formula (wherein, Z is a substituted or unsubstituted monovalent organic group having 1 to 20 carbon atoms).