JP3151144B2 - 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 polyethers having a hydrolyzable silicon group capable of forming a siloxane bond by hydrolysis to increase the molecular weight or being crosslinkable are known in the art (for example, see Japanese Patent Application Laid-Open No. 47825, JP-A-3-72527, JP-A-3-79627, Japanese Patent Publication No. Sho 4
6-30711, 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. When an alkali metal compound such as an alkali metal, an alkali metal hydroxide or an alkali metal hydride is used as the alkali in the above reaction, it is necessary to remove the alkali component.

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

On the other hand, in order to reduce the tackiness of a cured product, a photocurable compound or an air-curable compound is added.

[0006]

The polyoxyalkylene having a terminal hydroxyl group, which is a raw material of a polyether having a hydrolyzable silicon group, is generally obtained by addition polymerization of an alkylene oxide to an initiator in the presence of a catalyst. In recent years, it has become industrially possible to use metal compounds other than alkali metal compounds as polymerization catalysts for this alkylene oxide.

The polyether having a hydrolyzable silicon group has a high average molecular weight and a narrow molecular weight distribution, and thus has excellent curability. However, when a photo-curable compound or an air-curable compound is added, the surface weather resistance is poor. It turned out to be worse.

[0008]

Means for Solving the Problems The inventors have found that a decomposition product of a metal catalyst at the time of production of a raw material polyoxyalkylene remains, and that this specific impurity is produced by using a polyether having a hydrolyzable silicon group. It has been found that it has an adverse effect on the physical properties of the curable composition and its cured product.

The present invention is the following invention.

The following organic polymer (A) and 10
1 to 20 parts by weight of the air-curable compound (E) and / or 1 to 20 parts by weight of the photo-curable compound (F) based on 0 part by weight,
A curable composition comprising:

(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 derived from a compound represented by the 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 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.

[0012]

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.

[0013] The use of the double metal cyanide complex (B) results in a M
A hydroxyl group-containing polyoxyalkylene polymer (C) having a low _w / _Mn , a higher molecular weight, and a lower viscosity can be obtained.

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 can be further improved, and excellent curing can be achieved because the action of the curing catalyst is not hindered. Property is obtained.

The reduction method is as follows:
(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 "hydroxyl equivalent molecular weight" means the number of functional groups of the initiator used for producing the polyoxyalkylene polymer (C) having a terminal hydroxyl group, and the molecular weight per hydroxyl group of the polyoxyalkylene of the polymer. Refers to 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. 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.

The terminal unsaturated group-introduced product (D) of the 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) Compound having isocyanate group and hydrolyzable silicon group represented by formula (1) and 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. ^{_{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 a hydroxyl group, a carboxyl An active hydrogen-containing group selected from a 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.

In the present invention, an air-curable compound (E) and / or a photo-curable compound (F) are used together with the organic polymer (A). Use of the air-curable compound (E) is effective in improving the initial tack, and use of the photo-curable compound (F) is effective in improving the stain resistance. The air-curable compound (E) and the photo-curable compound (F) are preferably used in combination.

As the air-curable compound (E) used in the present invention, a compound having an unsaturated group in the molecule which is polymerized by oxygen in the air is preferable. Specific examples include the following compounds.

Drying oils such as paulownia oil, linseed oil, eno oil, soybean oil, sunflower oil, and rapeseed oil; various alkyd resins obtained by modifying the drying oil; reaction products of the drying oil with the functional polyoxyalkylene; A reaction product (urethane oil) of a drying oil and an isocyanate compound, an acrylic polymer modified with the drying oil, an epoxy resin, and a silicone resin.

Butadiene, chloroprene, isoprene,
A liquid polymer obtained by homopolymerizing or copolymerizing a diene compound having 4 to 8 carbon atoms such as 1,3-pentadiene, a monomer such as acrylonitrile or styrene having copolymerizability with the diene compound is used as a diene compound. Polymers such as NBR and SBR obtained by copolymerization so as to be a main component, and various modified products thereof (maleated modified products, boiled oil modified products, etc.).

Of these, drying oils, liquid diene polymers and modified products thereof are particularly preferred. The air-curable compound (E) may be used alone or in combination of two or more.

The effect may be enhanced by using a catalyst or a metal dryer which promotes the oxidation curing reaction together with the air-curable compound (E). Examples of these catalysts and metal dryers include metal salts such as cobalt naphthenate, lead naphthenate, zirconium naphthenate, cobalt octylate, and zirconium octylate, and amine compounds.

When the air-curable compound (E) is used, the amount used is preferably 0.1 to 100 parts by weight of the organic polymer (A).
01 to 20 parts by weight. If the amount is less than 0.01 part by weight, the effect of improving the initial tack, which is the purpose of using the air-curable compound (E), is insufficient, and if it exceeds 20 parts by weight, elongation of the cured product is impaired. The preferred amount is 1
To 10 parts by weight.

Photocurable compound (F) used in the present invention
The term “light” means that the molecular structure undergoes a chemical change in a very short time due to the action of light, thereby causing a physical property change such as curing.
Many compounds, such as monomers, oligomers, resins and compositions containing them, are known as such compounds.
Any commercially available one can be used. Representative examples include unsaturated acrylic compounds, polyvinyl cinnamate, and azide resin, and unsaturated acrylic compounds are particularly preferable.

As the unsaturated acrylic compound, a monomer or oligomer having one to several acryloyl groups or methacryloyl groups, or a mixture thereof is preferable, and a compound having an acryloyl group is particularly preferable. More specifically, propylene (or butylene, ethylene)
Monomers such as glycol di (meth) acrylate and neopentyl glycol di (meth) dimethacrylate and oligoesters having a molecular weight of 10,000 or less obtained by polymerizing the monomers are preferred.

When the photocurable compound (F) is used, the amount used is preferably 0.0 to 100 parts by weight of the organic polymer (A).
1 to 20 parts by weight. If the amount is less than 0.01 part by weight, the improvement of stain resistance, which is the purpose of using the photocurable compound (F), is insufficient, and if it exceeds 20 parts by weight, elongation of the cured product is impaired. The preferred amount is 1 to 10 parts by weight.

The composition of the present invention may further include, if necessary,
A curing catalyst, a plasticizer, a filler, an adhesion-imparting agent, and other additives may be added for use.

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; dibutylamine-2
Amine salts such as ethylhexoate; and other acidic and basic catalysts can be used. The curing catalyst is preferably used in an amount of 0.001 to 10 parts by weight, especially 0.01 to 5 parts by weight, per 100 parts by weight of the organic polymer (A). preferable.

As the plasticizer, known plasticizers can be used, and specifically, phthalic esters such as dioctyl phthalate, dibutyl phthalate and butyl phthalate; dioctyl adipate, isodecyl succinate, dibutyl sebacate, Aliphatic carboxylic acid esters such as butyl oleate;
Glycol esters such as pentaerythritol ester; phosphate esters such as trioctyl phosphate and tricresyl phosphate; epoxy plasticizers such as epoxidized soybean oil and benzyl epoxystearate; chlorinated paraffins and the like alone or in combination of two or more Can be used with

The composition of the present invention may contain fillers, reinforcing agents, anti-sagging agents, adhesives and the like.

The amount of the filler used is preferably from 0 to 1000% by weight, particularly preferably from 50 to 250% by weight, based on the organic polymer (A). The following are specific examples of the filler. These fillers may be used alone or in combination of two or more.

Calcium carbonate, fumed silica, precipitated silica, silicic anhydride, hydrous silicic acid and carbon black, magnesium carbonate, diatomaceous earth, calcined clay, clay, talc, titanium oxide, bentonite, organic bentonite, ferric oxide, Powdered fillers such as zinc oxide, activated zinc flower, shirasu balloon, wood flour, pulp, cotton chips, mica, walnut flour, fir flour, graphite, aluminum fine powder, flint powder, asbestos, glass fiber, glass filament, Fibrous fillers such as carbon fiber, Kevlar fiber and polyethylene fiber.

Examples of the adhesion-imparting agent include silane coupling agents such as aminosilane and epoxysilane, phenolic resins and epoxy resins.

Other pigments include inorganic pigments such as iron oxide, chromium oxide, and titanium oxide, and organic pigments such as phthalocyanine blue and phthalocyanine green; as an anti-sagging agent, organic acid-treated calcium carbonate, hydrogenated castor oil, calcium stearate, zinc stearate; Various antioxidants such as finely divided silica, ultraviolet absorbers and the like can be used.

The curable composition of the present invention cures at room temperature in the presence of moisture and can be used particularly for elastic sealants, adhesives and coating materials.

[0060]

【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 at 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 10 g of Kyoward 600 (synthetic magnesia silicate, manufactured by Kyowa Chemical Industry) was added. Dissolve and filter out the impurities 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.

(Production Example 1 of Polymer) Methyldimethoxysilane was added to the polymer A1 obtained by (Purification of Polymer a) 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.

(Preparation Example 2 of Polymer) Methyldimethoxysilane was added to the polymer A2 obtained in (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.

(Photocurable compounds) The photocurable compounds used in the examples are as shown in Table 3.

(Examples or Comparative Examples) 100 parts by weight of the organic polymer P1 or P2 was added to 100 mg of colloidal calcium carbonate.
20 parts by weight, heavy calcium carbonate 20 parts by weight, terminal 9
55 parts by weight of a high molecular weight polyether plasticizer in which 0% or more is converted to an allyloxy group, 5 parts by weight of dioctyl phthalate, 3 parts by weight of an epoxy resin (Epicoat 828), 3 parts by weight of hydrogenated castor oil, 5 parts by weight of titanium oxide Parts, 1 part by weight of a phenolic antioxidant, 3 parts of tung oil, which is an air-curable compound (E), and 5 parts by weight of a photocurable compound (F) shown in Table 2, and kneaded using a three paint roll. A composition was obtained.

Further, 3 parts by weight of tin dioctylate, 0.5 part by weight of laurylamine, 6.5 parts by weight of dioctyl phthalate, and 20 parts by weight of heavy calcium carbonate were previously mixed with this composition, and three paint rolls were prepared. The mixture was kneaded using a hardening agent, and cured at 20 ° C. and 65% humidity for 7 days, and then cured at 50 ° C. and 60% humidity for 7 days to a thickness of 5 mm.
Sheet was obtained.

After 250 hours, 500 hours, and 750 hours, the surface weather resistance was measured with a sunshine weatherometer. The evaluation was evaluated as ○ when no surface crack was observed after the sunshine weatherometer test, Δ when hair crack was observed, and × when clearly crack was observed. Table 2 shows the results.

As shown in Examples 1 and 2 in Table 2, P1 having a low ionic impurity content and an air-curable compound (E)
The cured product of the composition composed of the combination of the photocurable compound (F) and the cured product of the composition composed of the same combination using P2 having a large ionic impurity content shown in Comparative Examples 1 and 2 Excellent surface weather resistance.

[0070]

[Table 1]

[0071]

[Table 2]

[0072]

[Table 3]

[0073]

The present invention has excellent surface weather resistance.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-70425 (JP, A) JP-A-8-231707 (JP, A) JP-A-6-200013 (JP, A) 502438 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 1/00-101/16

Claims (7)

(57) [Claims] 1. The following organic polymer (A) and 10
1 to 20 parts by weight of the air-curable compound (E) and / or 1 to 20 parts by weight of the photo-curable compound (F) based on 0 part by weight,
A curable composition comprising: (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 air-curable compound (E) is a drying oil. 3. The curable composition according to claim 1, wherein the photocurable compound (F) is a compound containing one or more acryloyl groups in a molecule. 4. The ionic impurity comprises (a) a metal compound derived from the double metal cyanide complex (B) and / or (b) an alkali metal compound.
The curable composition of any one of the above. 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.