JP3151142B2 - Curable composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a curable composition which cures in the presence of moisture.

[0002]

2. Description of the Related Art Several examples of a polyether having a hydrolyzable silicon group capable of forming a siloxane bond by hydrolysis and having a high molecular weight or capable of crosslinking are known in the art (for example, see Japanese Patent Application Laid-Open No. 47825, JP-A-3-72527, JP-A-3-79627, JP-B-46
-30711, JP-B-45-36319, JP-B-46-
17553).

[0003] Since these polyethers take a step of reacting with an organic halogen compound or the like under alkaline conditions as production conditions, salts are by-produced, and it is necessary to remove them. It is known that the residual salt increases the water absorption of a cured product obtained by curing a polyether having a hydrolyzable silicon group, and deteriorates water resistance. In addition, as the alkali in the above reaction, for example, when an alkali metal compound such as an alkali metal, an alkali metal hydroxide, or an alkali metal hydride is used, a polyether having a hydrolyzable silicon group produced depending on the case may be used. In some cases, the storage stability of a curable composition produced by adding a filler, a catalyst, and the like is significantly deteriorated.

A method for removing ionic components derived from these salts or alkalis has been proposed (for example, Japanese Patent Publication No. 61-29371).

[0005]

On the other hand, polyoxyalkylenes having a terminal hydroxyl group, which are the raw materials of polyethers having a hydrolyzable silicon group, are generally prepared by adding an alkylene oxide to an initiator in the presence of a catalyst. Although produced by polymerization, in recent years, it has become industrially possible to use a metal compound other than an alkali metal compound as a polymerization catalyst for this alkylene oxide.

The polyether having a hydrolyzable silicon group has a high average molecular weight and a narrow molecular weight distribution, and is therefore excellent in curability. However, when a hydrolyzable silicon group is introduced into a terminal hydroxyl group, the raw material polyoxyalkylene is produced. Decomposition products of the metal catalyst at the time remain, and the storage stability of the curable composition produced by adding a filler, a catalyst, and the like may be significantly deteriorated.

A composition obtained by adding a filler, particularly calcium carbonate, to a polyether having a hydrolyzable silicon group is used as a sealing agent or an adhesive, but poor storage stability causes a reduction in the pot life. This was a problem that had to be solved due to a decrease in workability.

[0008]

DISCLOSURE OF THE INVENTION The present invention aims at improving such problems, particularly the storage stability of the curable composition, and includes the following organic polymers (A) and (A). ) 100 to 100 parts by weight, average particle size 0.05 to 1.0 μm
m of the easily dispersed cubic calcium carbonate (E) from 10 to 30
A curable composition containing 0 parts by weight is provided.

(Organic polymer) A hydroxyl group-containing polyoxyalkylene polymer (C) obtained by polymerizing an alkylene oxide with an initiator using a double metal cyanide complex (B) as a catalyst is represented by the following formula (1). Having a hydrolyzable silicon group, and the total amount of ionic impurities is 50 ppm
The following organic polymer (A).

-R-SiX _a R ¹³ _-a (1) In the formula (1), R is a divalent organic group, and R ¹ is a group having 1 to 20 carbon atoms.
Is a substituted or unsubstituted monovalent hydrocarbon group, X is a hydroxyl group or a hydrolyzable group, and a is an integer of 1 to 3.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The organic polymer (A) is derived from a hydroxyl group-containing polyoxyalkylene polymer (C) obtained by polymerizing an alkylene oxide with an initiator using a double metal cyanide complex (B) as a catalyst. You.

The use of the double metal cyanide complex (B) results in a M
It is possible to obtain a hydroxyl group-containing polyoxyalkylene polymer (C) having a low _w / _Mn , a higher molecular weight and a lower viscosity.

As the double metal cyanide complex (B), a complex containing zinc hexacyanocobaltate as a main component is preferable, and an ether and / or alcohol complex thereof is particularly preferable. Its composition is essentially JP-B-46-2725.
No. 0 can be used. As ethers, ethylene glycol dimethyl ether (glyme),
Diethylene glycol dimethyl ether (diglyme)
Are preferred, and glyme is particularly preferred from the handling during the production of the complex. As the alcohol, t-butanol is preferable.

As the initiator, a compound having 2 to 10 active hydrogens is preferable, a polyhydroxy compound is preferable, and a polyhydroxy compound having 2 to 8, especially 2 to 4 hydroxyl groups is preferable. Specifically, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 1,
There are 4-butanediol, 1,6-hexanediol, glycerin, trimethylolpropane, pentaerythritol, diglycerin, sucrose, and polyols having a lower molecular weight than the target product obtained by reacting them with alkylene oxide. These may be used alone or in combination of two or more. Also, unsaturated group-containing monohydroxy compounds such as allyl alcohol can be used.

The organic polymer (A) of the present invention has a total amount of ionic impurities of 50 ppm or less. In particular, the present invention is suitable when the ionic impurities include (a) a metal compound derived from the double metal cyanide complex (B) and / or (b) an alkali metal compound. 3 ionic impurities
It is preferably at most 0 ppm, more preferably at most 20 ppm.

By reducing the amount of these metallic impurities, the storage stability of the organic polymer (A) and the curable composition of the present invention is further improved. Property is obtained.

As a method of reducing the above, the following (I) to
(III). The method (I) is particularly preferable because ionic impurities can be effectively and economically reduced.

(I) A method in which ionic impurities contained in a polymer are converted into a salt essentially insoluble in the polymer, and the salt is removed from the polymer. Specifically, after adding a compound capable of reacting with ionic impurities to form a salt essentially insoluble in the polymer, water and, if necessary, a nonionic surfactant,
There is a method of precipitating a salt by dehydration and then removing the salt. As the compound capable of forming a salt, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, pyrophosphoric acid, sodium acid pyrophosphate and the like are preferable. The precipitated salt can be removed by a filtration operation, an adsorption operation, or the like.

(II) A method of removing a ionic impurity by adding a solvent to a polymer and then bringing the polymer into contact with an anion exchange resin and / or a cation exchange resin.

(III) A method for removing a metal compound caused by a double metal cyanide complex (B) after treating with a pH buffer and optionally ammonia and a chelating agent, adding an aliphatic alcohol and a chelating agent, A method of removing a metal compound caused by the double metal cyanide complex (B), and a method of removing a metal compound caused by the double metal cyanide complex (B) after treatment with an oxidizing agent.

The ionic impurities referred to in the present invention are:
Cations and anions, such as zinc ions, cobalt ions, cyan ions, and chloride ions, caused by the double metal cyanide complex (B); sodium ions and potassium ions mixed as impurities in the step of producing the organic polymer (A) Alkali metal ions, halogen ions, etc .; carboxylate ions generated by oxidation of polyoxyalkylene in the step of producing the organic polymer (A); ester bonds in the step of producing the organic polymer (A),
Includes all anions and cations such as catalytic metal salts added when forming carbonate bonds and the like.

The organic polymer (A) has a hydrogen atom in the hydroxyl group of the hydroxyl group-containing polyoxyalkylene polymer (C),
What substituted by the group represented by Formula (1) is preferable.

The number of hydroxyl groups per molecule of the polyoxyalkylene polymer (C) used in the present invention is preferably 2 to 10. From the balance of physical properties such as viscosity, strength and elongation, it is particularly preferable that the number is 2 to 8, especially 2 to 4.

Preferred polymers (C) are polyoxypropylene diol, polyoxypropylene triol and polyoxypropylene tetraol. Further, when used in the following methods (a) and (d), unsaturated group-terminated polyoxyalkylene monols such as polyoxypropylene glycol monoallyl ether can also be used.

The polyoxyalkylene polymer (C) preferably has a molecular weight in terms of hydroxyl value of 5,000 to 30,000, more preferably 8,000 to 30,000.

In the present invention, the term "molecular weight in terms of hydroxyl value" means the number of functional groups of the initiator used when producing the polyoxyalkylene polymer (C) having a terminal hydroxyl group, and the molecular weight per hydroxyl group of the polyoxyalkylene of the polymer. Means the molecular weight calculated by the product of

The organic polymer (A) has a hydrolyzable silicon group represented by the formula (1). —R—SiX _a R ¹³ _-a (1) In the formula (1), R is a divalent organic group, and R ¹ is a carbon number of 1 to 20.
Is a substituted or unsubstituted monovalent hydrocarbon group, X is a hydroxyl group or a hydrolyzable group, and a is an integer of 1 to 3.

R in the formula (1) is a divalent organic group. R
¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, preferably an alkyl group having 8 or less carbon atoms, a phenyl group or a fluoroalkyl group. Particularly preferred are a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, a cyclohexyl group, a phenyl group and the like.

X is a hydroxyl group or a hydrolyzable group, and examples of the hydrolyzable group include a halogen atom, an alkoxy group, an acyloxy group, an amide group, an amino group, an aminooxy group, a ketoximate group and a hydride group. Among these, the number of carbon atoms of the hydrolyzable group having a carbon atom is preferably 6 or less, particularly preferably 4 or less. Preferred X includes a lower alkoxy group having 4 or less carbon atoms, particularly a methoxy group, an ethoxy group, a propoxy group, and the like. a is an integer of 1 to 3, preferably 2 or 3.

Next, a method for producing the organic polymer (A) will be described. In the organic polymer (A) in the present invention, a hydrolyzable silicon group can be introduced into the terminal of the hydroxyl group-containing polyoxyalkylene polymer (C) by the method described in the following (A) to (D). Such compounds are liquid at room temperature, and the cured product retains flexibility even at relatively low temperatures,
When used as a sealing material, an adhesive or the like, it has preferable characteristics.

(A) A method of reacting the terminal unsaturated group-introduced product (D) of the polymer (C) with a silicon hydride compound represented by the formula (2). ^{_{HSiX a R 1 3-a ···}} (2) However, Equation (2) Medium R ^1, X, a is as defined above.

Terminal unsaturated group-introduced product (D) of polymer (C)
Can be obtained by converting the terminal hydroxyl group OH of the polymer (C) to OM (M is an alkali metal) and then reacting the polymer with an unsaturated group-containing halogenated hydrocarbon such as allyl chloride or the like. There is a method in which a compound having a functional group capable of reacting is reacted with the polymer (C) and bound by an ester bond, a urethane bond, a carbonate bond, or the like. Further, when polymerizing the alkylene oxide in the production of the polymer (C), a method of introducing an unsaturated group into a side chain by copolymerizing an alkylene oxide having an unsaturated group such as allyl glycidyl ether or a terminal as an initiator. It can also be obtained by using an unsaturated group-containing monohydroxy compound.

(B) A compound having an isocyanate group and a hydrolyzable silicon group represented by the formula (1) and a polymer (C)
How to react.

(C) After the polymer (C) is reacted with a polyisocyanate compound such as tolylene diisocyanate to form an isocyanate group terminal, the W group of the silicon compound represented by the formula (3) is reacted with the isocyanate group. How to let.

[0035] ^{_{R 1 3-a -SiX a -R}} 5 W ··· (3) However, Equation (3) Medium R ^1, X, a are as defined above, R ⁵ is a divalent organic radical, W is An active hydrogen-containing group selected from a hydroxyl group, a carboxyl group, a mercapto group and an amino group (primary or secondary).

(D) Formula (3) wherein W is a mercapto group and the unsaturated group of the terminal unsaturated group-introduced product (D) of the polymer (C)
And reacting the mercapto group of the silicon compound represented by

The removal of the ionic impurities is as described in (a) to (d) above.
In each method of (d), it is preferable to carry out at an appropriate stage such as before the reaction of each silicon compound, and the total amount is 50 ppm or less. The following method (e) or (f) is preferred.

(E) After converting the ionic impurities contained in the polymer (C) into a salt essentially insoluble in the polymer (C),
After removing the salt from the polymer (C) to reduce the ionic impurities contained in the polymer (C) to 50 ppm or less, a hydrolyzable silicon group is introduced into the polymer (C),
Organic polymer (A).

(F) After converting the ionic impurities contained in the terminal unsaturated group-introduced product (D) of the polymer (C) into a salt essentially insoluble in the terminal unsaturated group-introduced product (D), By removing the salt from the terminal unsaturated group-introduced product (D), ionic impurities contained in the terminal unsaturated group-introduced product (D) are reduced to 50 pp.
m or less, the terminal unsaturated group-introduced product (D) and the formula (2)
To produce an organic polymer (A).

The molecular weight of the organic polymer (A) in the present invention is calculated based on the hydroxyl value-converted molecular weight of the polymer (C) as a raw material. The molecular weight is 5,000 to 30,000
Is preferred. If it is lower than 5,000, the cured product is hard and the elongation is low. If it exceeds 30,000, the flexibility and elongation of the cured product are not problematic, but the viscosity of the polymer itself becomes extremely high and the practicality is lowered. Especially 8000-30
000 is preferred.

The average particle size used in the present invention is 0.05 to
1.0 μm easily dispersed cubic calcium carbonate (E)
For example, a suspension of calcium hydroxide to which fine cubic calcium carbonate is added and mixed as a nucleating agent is sprayed into a carbon dioxide gas stream, or the suspension is quickly converted to carbon dioxide by another reaction method such as a packed tower. By conducting the contact reaction frequently and frequently, crystals can be produced by sequentially growing crystals on the nucleating agent.

In order to improve the workability (thixotropic property) of the composition such as a sealing material and the tensile properties of the cured product (high elongation and high strength), the calcium carbonate is used for the purpose of the present invention. Is more desirably surface-treated with an organic substance.

Examples of the surface treating agent include higher fatty acid-based organic substances, resin acid-based organic substances, aromatic carboxylic acid esters, cationic surfactants, and nonionic surfactants. Specifically, as a higher fatty acid-based organic substance, for example, an alkali metal salt of a higher fatty acid such as sodium stearate having 10 or more carbon atoms; as a resin acid-based organic substance, for example, abietic acid, neoabietic acid, d-
Pimaric acid, id-pimaric acid, bodocapric acid, benzoic acid, cinnamic acid, etc .; as aromatic carboxylic acids, for example, esters of phthalic acid such as octyl alcohol, butyl alcohol, isobutyl alcohol, lower alcohol esters of naphthoic acid, and rosin Lower alcohol esters of acids and aromatic polycarboxylic acids, such as maleic acid adducts of aromatic dicarboxylic acids or rosin acids, or partial esterifications of different alcohols; and anionic surfactants such as dodecylbenzenesulfonic acid; Anionic surfactants of the sulfate or sulfonic acid type, such as sodium lauryl sulfonate and dodecylbenzene sulfonic acid, may be mentioned.

These surface treatment agents may be used alone or in combination of two or more. For example, those obtained by adsorbing a higher fatty acid-based organic substance and a resin acid-based organic substance such that the total amount thereof is in the range of 0.2 to 4 parts by weight per 100 parts by weight of calcium carbonate, or a sulfate ester type or sulfone type An acid-type anionic surfactant and an ester of an aromatic carboxylic acid can be added in a ratio of 5 to 20 parts by weight of the former to 10 parts by weight of the latter. In the present invention, it is particularly preferable to use an anionic surfactant alone or in combination with another surface treating agent.

These easily dispersible cubic calcium carbonates (E) may be used alone or in combination of two or more. The average particle size is 1 to 3μ, also called calcium dicarbonate.
It is also possible to use in combination with so-called heavy calcium carbonate having an average particle diameter of 4 to 20 μm obtained by grinding and classifying crystalline calcium carbonate or limestone from the spindle-shaped calcium carbonate or limestone produced by the sedimentation method.

The easily dispersible cubic calcium carbonate (E) is
It is used in an amount of 10 to 300 parts by weight based on 100 parts by weight of the organic polymer (A). Preferably, 30 to 200 parts by weight are used. If the amount is less than 10 parts by weight, the obtained composition has insufficient thixotropic properties, and the effect of improving the tensile properties after curing is also insufficient. If it exceeds 300 parts by weight, the tensile properties are significantly reduced.

In the present invention, a curing catalyst may be used to accelerate the curing of the organic polymer. As the curing catalyst, a compound known as a catalyst for hydrolysis and condensation of a hydrolyzable silicon group can be used. Metal salts of carboxylic acids such as alkyl titanates, organosilicon titanates, tin octylate and dibutyltin dilaurate; amine salts such as dibutylamine-2-ethylhexoate; and other acidic catalysts and Basic catalysts can be used. As the amount of the curing catalyst used, the amount of the organic polymer (A) 1
0.001 to 10 parts by weight, especially 0.1 to 100 parts by weight.
It is preferable to use from 01 to 5 parts by weight.

The composition of the present invention may further contain other fillers, reinforcing agents, anti-sagging agents, adhesives and the like, if necessary. As fillers, talc, clay, silica, etc., as reinforcing agents, carbon black, finely divided silica, etc., as pigments, inorganic pigments such as iron oxide, chromium oxide, titanium oxide, and organic pigments such as phthalocyanine blue, phthalocyanine green, etc. Examples of the pigment include hydrogenated castor oil, calcium stearate, zinc stearate, and fine powder silica as the anti-sagging agent, and examples of the adhesive include aminosilane and epoxysilane.

In the present invention, a plasticizer can be optionally used. As the plasticizer, known plasticizers can be used, and specifically, phthalic esters such as dioctyl phthalate, dibutyl phthalate and butyl benzyl phthalate; dioctyl adipate, isodecyl succinate, dibutyl sebacate, butyl oleate and the like Aliphatic carboxylic acid esters; glycol esters such as pentaerythritol ester; phosphates such as trioctyl phosphate and tricresyl phosphate; epoxy plasticizers such as epoxidized soybean oil and benzyl epoxystearate; chlorinated paraffins alone Alternatively, they can be used in a mixture of two or more.

The composition of the present invention can further contain various known additives and the like. As the additive, an adhesion imparting agent such as a phenol resin and an epoxy resin, various antioxidants, an ultraviolet absorber and the like can be used.

The curable composition at room temperature of the present invention is stable for a long period of time under sealing, cures in the presence of moisture at room temperature, and can be used particularly for elastic sealants and adhesives.

[0052]

【Example】

(Synthesis of polymer) Hydroxyl value using a glycerin-propylene oxide adduct having a molecular weight of 1,000 as an initiator and a zinc hexacyanocobaltate glyme complex as a catalyst.
A polyoxypropylene polymer of 0 mgKOH / g was obtained. This was reacted with allyl chloride in the presence of an alkali to convert the terminal hydroxyl group to an allyloxy group, thereby obtaining a polymer containing impurities such as metal ions.

(Purification of polymer a) To 1 kg of a polymer containing impurities such as metal ions, 5 g of a polyoxypropylene polymer having a molecular weight of 10,000 obtained by block-polymerizing ethylene oxide to 10% of terminals, 50 g of water and 10 g of sodium acid pyrophosphate were added. The mixture was stirred at 90 ° C. for 1 hour. Subsequently, water was distilled off under reduced pressure at 90 ° C., and then Kyoward 600 (synthetic magnesia silicate, manufactured by Kyowa Chemical)
Was added thereto, and the polymer was dehydrated under reduced pressure at 90 ° C. for 1 hour. Then, 2 liters of hexane was added to dissolve the polymer, and impurities were removed by filtration using filter paper. Thereafter, hexane was distilled off under reduced pressure to obtain a purified polymer A1.

(Purification of polymer a) Except that 1 g of sodium acid pyrophosphate was added,
A purified polymer A2 was obtained in exactly the same manner as described above.

(Preparation Example 1 of Polymer) Methyldimethoxysilane was added to the polymer A1 obtained by (purification of polymer a) by using chloroplatinic acid as a catalyst to give 0.17.
Thus, a polymer P1 having mmol / g of a hydrolyzable silicon group at the terminal was obtained. Table 1 shows the content of the ionic impurities contained in the composition.

(Production Example 2 of Polymer) Methyldimethoxysilane was added to the polymer A2 obtained by (Purification of Polymer A) using chloroplatinic acid as a catalyst to give 0.16.
A polymer P2 having mmol / g of a hydrolyzable silicon group at a terminal was obtained. Table 1 shows the content of the ionic impurities contained in the composition.

(Examples and Comparative Examples) With respect to 100 parts by weight of the organic polymer P1 or P2, calcium carbonate shown in Table 2 (the numbers in Table 2 are parts by weight) and dioctyl phthalate 5
0 parts by weight, 3 parts by weight of hydrogenated castor oil and 1 part by weight of a phenolic antioxidant were added and kneaded using three paint rolls to obtain a composition. To this was added 2 parts by weight of dibutyltin diacetylacetonate as a curing agent,
The time-dependent change in viscosity at 65 ° C. and 65% humidity was measured with a B8R viscometer (No. 6 rotor) at 5 rpm, and the time until the viscosity reached 800,000 cP was defined as the pot life. Also JIS
Slump (vertical) at 35 ° C. was measured based on A5758.

Further, the composition obtained in the same manner was sealed and stored in a gear oven at 60 ° C. for 2 weeks, after which a curing agent was added, and the pot life was examined in the same manner. Table 2 shows these pot life.

Table 2 shows the average particle size and the particle shape of the calcium carbonate used in the examples and comparative examples.

As shown in Examples 1 to 4 in Table 3, the composition containing P1 and calcium carbonate satisfying the conditions of the present invention had an initial pot life and pot life after storage at 60 ° C. for 2 weeks. The time difference is small. On the other hand, as shown in Comparative Examples 1 to 4 in Table 4, the composition comprising the same combination of P2 has a remarkable reduction in the pot life.

On the other hand, as shown in Comparative Examples 5 to 8 in Table 5,
A composition containing only calcium carbonate that does not satisfy the conditions in the present invention has a small decrease in the pot life, regardless of the amount of ionic impurities in the polymer, but has an extremely large slump and is difficult to use as a non-sag type sealant. It is.

[0062]

[Table 1]

[0063]

[Table 2]

[0064]

[Table 3]

[0065]

[Table 4]

[0066]

[Table 5]

[0067]

According to the present invention, a curable composition having excellent storage stability and suitable for use as a non-sag type sealant can be obtained.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-90170 (JP, A) JP-A-7-90169 (JP, A) JP-A 8-231707 (JP, A) JP-A-6-90 200013 (JP, A) Special Table Hei 6-502438 (JP, A) (58) Fields surveyed (Int. Cl. ⁷ , DB name) C08L 1/00-101/16

Claims (7)

(57) [Claims] An average particle size of 0.05 to 1.0 μm per 100 parts by weight of the following organic polymer (A) and organic polymer (A).
m of the easily dispersed cubic calcium carbonate (E) from 10 to 30
A curable composition containing 0 parts by weight. (Organic Polymer) Hydroxyl represented by the formula (1) derived from a hydroxyl group-containing polyoxyalkylene polymer (C) obtained by polymerizing an alkylene oxide with an initiator using a double metal cyanide complex (B) as a catalyst. Having a decomposable silicon group,
And an organic polymer (A) having a total amount of ionic impurities of 50 ppm or less. —R—SiX _a R ¹³ _-a (1) In the formula (1), R is a divalent organic group, and R ¹ is a carbon number of 1 to 20.
Is a substituted or unsubstituted monovalent hydrocarbon group, X is a hydroxyl group or a hydrolyzable group, and a is an integer of 1 to 3. 2. The curable composition according to claim 1, wherein the surface of the easily dispersible cubic calcium carbonate (E) is treated with an organic substance. 3. The curable composition according to claim 2, wherein the organic substance used for the surface treatment of the easily dispersible cubic calcium carbonate (E) is an anionic surfactant or a mixture containing the same. 4. The curing method according to claim 1, wherein the ionic impurities include (a) a metal compound derived from the double metal cyanide complex (B) and / or (b) an alkali metal compound. Composition. 5. The organic polymer (A) converts ionic impurities contained in the polymer (C) into a salt essentially insoluble in the polymer (C), and then converts the salt into the polymer (C). ), The ionic impurities contained in the polymer (C) are reduced to 50 p.
The curable composition according to any one of claims 1 to 4, wherein the curable composition is an organic polymer obtained by introducing a hydrolyzable silicon group into the polymer (C) after the pm or less. 6. The organic polymer (A) comprises an ionic impurity contained in the terminal unsaturated group-introduced product (D) of the polymer (C),
After forming a salt essentially insoluble in the terminal unsaturated group-introduced product (D), the salt is removed from the terminal unsaturated group-introduced product (D) to be contained in the terminal unsaturated group-introduced product (D). An organic polymer obtained by reducing the ionic impurity to 50 ppm or less and then reacting the terminal unsaturated group-introduced product (D) with the silicon hydride compound represented by the formula (2).
5. The curable composition according to any one of to 4). HSiX _a R ¹ _3-a in (2) Formula (2), R ¹ is a monovalent hydrocarbon group having a substituted or unsubstituted 1 to 20 carbon atoms, X is a hydroxyl group or a hydrolyzable group,
a is an integer of 1 to 3. 7. A polymer (C) having a hydroxyl value-converted molecular weight of 50.
The curable composition according to any one of claims 1 to 6, which has a molecular weight of from 00 to 30,000.