JPH01279958A - Curable composition - Google Patents

Abstract

PURPOSE:To make it possible to improve the dryability of an alkyd coating material by using at least two specified oxyalkylene polymers. CONSTITUTION:A hydrosilane compound formed by bonding H to a group of formula I [wherein R<2> is a 1-20C (un)substituted monovalent organic group or a triorganosiloxy group, provided that [m(2-a)+3-b] R<2> groups may be different from each other, X is a hydroxyl group or a hydrolyzable group, provided that (ma+b) X groups may be different from each other, a is 0-2, b is 0-3, and (ma+b)>=1 and m is 0-19] and an oxyalkylene polymer having an olefin group of formula II (wherein R<3> is H or a 1-20C monovalent organic group, R<4> is a 1-20C bivalent organic group, and c is 0 or 1) are subjected to an addition reaction in the presence of a Group VIII transition metal compound to obtain an oxyalkylene polymer (A) having at least one S-containing group having an Si-bonded hydroxyl group or hydrolyzable group and being crosslinkable by forming a siloxane bond. 100pts.wt. component A is mixed with 10-500pts.wt. hydroxylated oxyalkylene polymer of a number-average MW>=4,000 and/or a non-hydroxylated oxyalkylene polymer (B).

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to silicon-containing groups (hereinafter referred to as reactive (also called silicon group)
An oxyalkylene polymer containing a high molecular weight hydroxyl group and (or)
A curable composition containing an oxyalkylene polymer that does not substantially contain hydroxyl groups, the curable composition having improved drying properties of an alkyd paint applied to a cured product from the composition. .

[Conventional technology/challenge to be solved by the invention] Oxyalkylene polymers with reactive silicon groups, like room-temperature-curing silicone rubber, harden even when exposed to moisture in the air at room temperature, forming rubber-like materials. It is a polymer that gives This cured product has excellent elongation properties, strength, adhesive properties, etc.
Used in applications such as sealants and adhesives.

One of the characteristics of the oxyalkylene polymer having a reactive silicon group is that since the main chain is an oxyalkylene polymer, the surface of the cured product can be coated with most commonly used paints. In the case of silicone rubber, there is a problem in that the surface is water- and oil-repellent, and it is practically impossible to apply paint to it.

However, depending on the type of composition, the drying properties of the coating film (
In some cases, the problem arises that the coating composition has poor curability, making it difficult in practice to use the coating composition for the cured product.

In such cases, the idea of applying an alkyd paint onto a cured product of a sealant using an oxyalkylene polymer has been given up on.

However, the alkyd-based paint dries faster than oil-based paints, and the paint film is hard, glossy, and has poor adhesion.
It is excellent in most aspects such as weather resistance, oil resistance, and resistance, and its physical properties can be adjusted over a wide range depending on the type of modified oil, oil length, and type of modification, so it is a paint used for various purposes. be. Therefore, it is very beneficial to be able to apply this paint to the surface of a cured product.

Until now, even the cause of the deterioration in the drying properties of alkyd paints was completely unknown, but as a result of extensive research into this cause, the present inventors found that they contain oxyalkylene polymers that have reactive silicon groups. It has been found that when a conventional low-molecular plasticizer is added to a curable composition, drying properties are deteriorated. The plasticizer is added when it is necessary to lower the viscosity of the composition (improving workability during use) or improving the tensile properties of the cured product.

Since using a plasticizer is a simple method to reduce the viscosity of the composition and improve the tensile properties of the cured product, the present inventors investigated whether there is a plasticizer that does not worsen the drying properties of alkyd paints. As a result of research, it has been found that the above problems can be improved by using a polymer plasticizer.

Among polymer plasticizers, oxyalkylene polymers are inexpensive, and when added to oxyalkylene polymers containing reactive silicon groups, the cured product has excellent tensile properties at low temperatures. It is a plasticizer.

As a result of studying various oxyalkylene polymers, the present inventors found that when a specific oxyalkylene polymer is used as a plasticizer for an oxyalkylene polymer having a reactive silicon group, the cured product becomes an extremely good alkyd. It was discovered that it has paint drying properties, leading to the present invention.

[Means for Solving the Problems] That is, the present invention provides (A) a silicon-containing group having a hydroxyl group or a hydrolyzable group bonded to a silicon atom and having at least one silicon-containing group capable of crosslinking by forming a siloxane bond. Oxyalkylene polymer and (B) selected from the group consisting of (1) an oxyalkylene polymer containing hydroxyl groups with a number average molecular weight of 4000 or more, and O) an oxyalkylene polymer containing substantially no hydroxyl groups The present invention relates to a curable composition containing at least one kind of polymer, which has improved drying properties of an alkyd-based paint applied to a cured product from the composition.

〔Example〕

In the present invention, an oxyalkylene polymer having at least one reactive silicon group (hereinafter also referred to as oxyalkylene polymer (A)) is used.

The oxyalkylene polymer (A) is
No. 36319, No. 4B-12154, No. 49-326
No. 73, JP-A-50-158599, JP-A No. 51-735
No. 81, No. 54-6096, No. 55-82123,
No. 55-123620, No. 55-125121,
These are polymers proposed in publications such as No. 55-131022, No. 55-135135, and No. 55-137129.

The molecular chain of the oxyalkylene polymer (A) essentially has the general formula: % formula % (wherein R1 is a divalent hydrocarbon group, most of which are alkylene groups having 3 or 4 carbon atoms It is preferable that the repeating unit has a repeating unit shown in (most preferable when it is). Specific examples of R1 include CH3 -CH2CH2CR2CH2-. The molecular chain of the oxyalkylene polymer (A) may consist of only one type of repeating unit, or may consist of two or more types of repeating units, but CH.

As R1, -〇　)I　CR2- is particularly preferred.

In addition, the main chain of the oxyalkylene polymer has the general formula: −
It may consist only of the repeating unit represented by R1-0-, but it may also contain other repeating units. If it contains other repeating units, the general formula is: -R1
The repeating unit represented by -0- accounts for 60% (wt%) in the polymer.
, hereinafter the same) or more, and more preferably 80% or more.

The reactive silicon group that can be crosslinked and/or polymerized by forming a siloxane bond in the oxyalkylene polymer (^) is a well-known functional group, and has the characteristic that it can be crosslinked even at room temperature. There is. A representative example of this reactive silicon group is - Formula (I): (wherein, R2 is a substituted or unsubstituted monovalent organic group having 1 to 2 carbon atoms or a triorganosiloxy group, and (s(
2-a) + 3-b) pieces (7) R2haj4? , C
X is a hydroxyl group or a hydrolyzable group, (la+b) X's may be different, a is 0.
1 or 2, b is 0, 1.2 or 3, and (a
+a+b)≧1, the minor is an integer from θ to 19, and the a's in the - numbers do not need to be the same). - Among the reactive silicon groups represented by the formula (1), the group represented by the general formula (■): (wherein R2 is the same as above and g is 1.2 or 3) is preferable.

Specific examples of the hydrolyzable group which is IFJ of Examples include alkenyloxy groups. Among these, alkoxy groups such as methoxy and ethoxy groups are preferred because they are mildly hydrolyzable.

Specific examples of R2 in formula (1) include alkyl groups such as methyl and ethyl groups, cycloalkyl groups such as cyclohexyl, aryl groups such as phenyl, aralkyl groups such as benzyl, and (R = )
Triorganosiloxy represented by 35IO- (R- is a substituted or unsubstituted monovalent organic group having 1 to 20 carbon atoms, such as a methyl group or a phenyl group, and the three R's do not need to be the same) Examples include bases. Among these, methyl group is particularly preferred.

The number of reactive silicon groups in the oxyalkylene polymer (A) should be 1 or more per molecule, but from the viewpoint of maintaining sufficient curability, the average number of reactive silicon groups is 1.1 or more, and more preferably 1.5. -4 is preferred.

In addition, the reactive silicon group is an oxyalkylene polymer (A)
Preferably, it exists at the end of the molecular chain.

The average molecular weight of the oxyalkylene polymer (A) over several years is 3.
, 000 to 30.000 is preferable, and 5.00
0 to 15,000 is more preferable. The oxyalkylene polymer (A) may be used alone or in combination of two or more.

For example, the oxyalkylene polymer (A) has the formula (
A hydrosilane compound in which a hydrogen atom is bonded to a group represented by 1) and general formula (III).

R3 [) (JI2- C-114-(0) - (wherein, R3 is a hydrogen atom or a monovalent group having 1 to 20 carbon atoms, R4 is an organic group having 1 to 20 carbon atoms, and C is 0 or 1
) with an olefin group-containing oxyalkylene polymer by an addition reaction using a Group I transition metal compound such as a platinum compound as a catalyst.

Methods for producing oxyalkylene polymers (A) other than those described above include: (1) reacting a hydroxyl group-terminated oxyalkylene polymer with a polyisocyanate compound such as toluene diisocyanate to produce an isocyanate group-terminated alkylene oxide polymer; The isocyanate group is then converted into the isocyanate group by the general formula: A method of reacting the V group of a silicon compound shown in A method of addition-reacting a mercapto group of a silicon compound, and
A specific example is a method of reacting a compound represented by the formula M: (wherein R2, R4, X and g are the same as above), but the present invention is not limited to these methods.

- In the method of reacting a hydrosilyl compound in which a hydrogen atom is bonded to a group represented by formula (1) with an oxyalkylene polymer having an olefin group represented by general formula (5), after reacting them, Some or all of the X groups may be further converted into other hydrolyzable groups or hydroxyl groups.

For example, if the X group is a halogen atom or a hydrogen atom,
It is preferable to use these groups after converting them into an alkoxy group, an acyloxy group, an aminooxy group, an alkenyloxy group, a hydroxyl group, or the like.

- In formula (I), R3 is a hydrogen atom or has 1 carbon atom
~20 substituted or unsubstituted monovalent organic groups,
A hydrogen atom or a hydrocarbon group is preferable, and a hydrogen atom is particularly preferable.

The above R4 is a divalent organic group having 1 to 20 carbon atoms, but -
R5-, -R50R5-1 to lO divalent hydrocarbon groups), etc. are preferable,
A methylene group is particularly preferred.

- As a specific method for producing an oxyalkylene polymer having an olefin group represented by the formula circle, for example, as disclosed in JP-A-54-6097, Allyl glycidyl ether, etc. is produced by reacting a compound with an unsaturated group and bonding it with an ether bond, ester bond, urethane bond, carbonate bond, etc., or when polymerizing an epoxy compound such as ethylene oxide or propylene oxide. Examples include a method of introducing an olefin group into the side chain by adding and copolymerizing an olefin group-containing epoxy compound.

The oxyalkylene polymer (hereinafter also referred to as oxyalkylene polymer (B)) used in the present invention together with the oxyalkylene polymer (A) reduces the viscosity and cost of the composition, and improves the composition. This component is used to adjust the properties such as hardness and elastic modulus of the cured product, and also to make it easier to dry the coating film when the cured product is coated with an alkyd paint.

Oxyalkylene polymer (B) has (1) number average molecule m
Oxyalkylene polymers containing 4,000 or more hydroxyl groups (hereinafter referred to as oxyalkylene polymers (C)) and oxyalkylene polymers containing substantially no hydroxyl groups (hereinafter referred to as oxyalkylene polymers (D)) )
It is at least one oxyalkylene polymer selected from the group consisting of:

Since the oxyalkylene polymer (B) is used as a plasticizer, it does not contain a group that crosslinks at room temperature, such as the reactive silicon group that the oxyalkylene polymer (A) has.

As in the case of the oxyalkylene polymer (A), the main chain of the oxyalkylene polymer (B) essentially consists of 60% or more, preferably 80% of the monomer units constituting the main chain. It is preferable that the above is represented by the general formula: % formula %. In R1, H3 or -〇〇CH2- is preferred.

The number average molecular weight of the oxyalkylene polymer (C) is 40
00 or more, preferably 4500 or more, more preferably 5000-15,000. When the number average molecular weight is less than 4,000 and the polymer contains hydroxyl groups, the drying properties of the coating film tend to deteriorate when an alkyd coating is applied to the cured product.

Furthermore, the proportion of components with a number average molecular weight of 1,000 or less is 1
It is preferably 0% (ratio from the value determined by Al1 by GPC method, the same applies hereinafter) or less because the drying properties of the alkyd paint are improved, and 5% or less is particularly preferred.

In addition, the molecular weight of the oxyalkylene polymer (C) has a narrow distribution, that is, the weight average molecule ff1 (Ft,
)/number average molecular weight (turtle) is preferable from the viewpoint that the ratio of low molecular weight components is small and thus the drying properties of the applied alkyd paint are improved, and those with FM/Fh of 2 or less are more preferable; 1. More preferably, it is 5 or less.

Specific examples of such oxyalkylene polymers (C) include those having a number average molecular weight of 4000 or more,
Polyoxypropylene glycol with a narrow molecular weight distribution or a low content with a molecular weight of 1.000 or less, in which some of the hydroxyl groups of the polyoxypropylene glycol are alkyloxy groups, alkylphenyloxy groups, alkenyloxy groups, allyloxy groups, etc. The hydroxyl group is blocked by a hydrocarbon group, or a part of the hydroxyl group is blocked by a hydrocarbon group such as an alkyl group, aryl group, or alkenyl group through a bond such as a urethane bond, ester bond, urea bond, or carbonate bond. Examples include, but are not limited to, these.

The oxyalkylene polymer (D) is a polymer having substantially no hydroxyl groups.

If the oxyalkylene polymer (D) substantially contains hydroxyl groups, the drying properties of the coating film generally tend to deteriorate when the cured product is coated with an alkyd coating.

Since oxyalkylene polymers are usually produced by ionic polymerization of alkylene oxide, they usually contain hydroxyl groups, particularly terminal hydroxyl groups. There are various methods for obtaining an oxyalkylene polymer (D) from an oxyalkylene polymer having a hydroxyl group. For example, by utilizing the reactivity of hydroxyl groups and introducing substituted or unsubstituted hydrocarbon groups, 90 mol% or more, preferably 90%
5 mol% or more of the hydroxyl groups are converted to groups other than hydroxyl groups.

Examples of polymers in which hydroxyl groups have been converted to other groups include oxyalkylene polymers with terminal hydroxyl groups such as those listed as specific examples of the oxyalkylene polymer (C), which have ether bonds, urethane bonds, etc. Through bonds such as bonds, ester bonds, urea bonds, and carbonate bonds, alkyl groups such as methyl, ethyl, propyl, chloromethyl, benzyl, and glycidyl groups, and aryls such as phenyl, toluyl, and chlorophenyl groups can be formed. group, vinyl group,
Examples include oxyalkylene polymers blocked with iWI such as alkenyl groups such as allyl groups, or unsubstituted hydrocarbon groups, preferably c-c4o hydrocarbon groups. However, the polymer is not limited to these, and oxyalkylene polymers other than these may be used as long as they do not substantially contain hydroxyl groups.

Among the above oxyalkylene polymers (D), oxyalkylene polymers containing an alkenyl group are convenient to use because they serve as raw materials for the oxyalkylene polymer (A).

The molecular weight of the oxyalkylene polymer (D) is not particularly limited, but it is usually preferably about 1000 or more. Generally, when the number average molecular weight of the oxyalkylene polymer (D) increases, the coating properties of the alkyd coating composition are further improved. For example, when the molecular weight is 4,000 or more, the desirable coating properties of the alkyd coating composition can be improved. Furthermore, the molecular weight is 4500 or more, and <1. : 5000-150
00"?'Arno is preferable. Also, the content and molecular weight distribution of components having a number average molecular ffi of 1000 or less in the oxyalkylene polymer (D) are similarly described in the case of the oxyalkylene polymer (C). It is preferable that the component with a number average molecular Q of 1000 or less is lower, and R
The smaller w/& is, the more preferable.

The oxyalkylene polymer (B) may be used alone or in combination of 28 or more. Note that the oxyalkylene polymer (B) is the oxyalkylene polymer (A
) It may be blended as a solvent during production.

The amount of the oxyalkylene polymer (B) used is preferably 10 to 500 parts, and 20 to 200 parts per 100 parts (by weight, the same applies hereinafter) of the oxyalkylene polymer (A).
Part is more preferable. When the amount is less than 10 parts, the plasticizing effect is small and it is not practical in terms of lowering the elastic modulus and increasing elongation of the cured product, and when it exceeds 500 parts, curing tends to be slow.

A curing accelerator, filler, other additives, etc. may be added to the composition of the present invention, if necessary.

Examples of the curing accelerator that can be used in the present invention include organic tin compounds, acidic phosphoric esters, reaction products of acidic phosphoric esters and amines, saturated or unsaturated polyhydric carboxylic acids or their acid anhydrides, and organic titanates. compounds, organic aluminum compounds, organic zirconium compounds, etc.

Specific examples of the organic tin compound include dibutyltin dilaurate, dibutyltin dilarate, dibutyltin phthalate, tin octylate, and dibutyltin methoxide.

In addition, the acidic phosphoric acid ester is a phosphoric acid ester containing a portion of 10-P, and
H 1 for example (R-0), -P-(OH) a-a (
Specifically, organic acidic phosphoric acid esters represented by dhal or 2, R represents an organic residue, etc.
o)P(OH)2, [(CH3)2CHO]
z POH, [)10-CH2CH(0)1)012
P.O.H.

[HO-CI-bCH(OH)O]P(OH)2, [l
o-CH2CH(OH)C2H40] P(OH)2 and the like.

Furthermore, examples of the titanate compound include titanate esters such as tetrabutyl titanate, tetraisopropyl titanate, and triethanolamine titanate.

When a curing accelerator is used, the total amount added is preferably 0.1 to 20 parts per 100 parts of the oxyalkylene polymer (A).

Examples of the filler include solid calcium carbonate, light calcium carbonate, colloidal calcium carbonate, kaolin, talc, silica, titanium oxide, aluminum silicate, magnesium oxide, zinc oxide, and carbon black.

Examples of the other additives include hydrogenated castor oil,
Examples include anti-sagging agents such as organic bentonite, colorants, and anti-aging agents.

It goes without saying that a low molecular weight plasticizer such as dioctyl phthalate may be used in combination with the composition of the present invention as long as the effects of the present invention are achieved.

The composition of the present invention as described above can be usefully used as an adhesive, a paint, a coating film waterproofing agent, a sealing material, a molding material, a cast rubber material, a foaming material, and the like.

For example, when applied as a building sealant, 10 to 300 parts of an inorganic filler such as calcium carbonate, talc, or kaolin is usually added to 100 parts of the oxyalkylene polymer (A), and further oxidized if necessary. Titanium,
After adding appropriate amounts of pigments such as carbon black, ultraviolet absorbers, anti-aging agents such as radical chain inhibitors, and air-drying compounds such as drying oil and synthetic drying oil, the mixture is thoroughly and uniformly kneaded using a kneader or paint roll. When applied and exposed to moisture in the air, it hardens quickly, for example within an hour to several days, and has good weather resistance, transparency, and
A rubber elastic material that exhibits tensile elongation can be changed.

When applied as a paint, it cures in the same manner as described above, resulting in a cured product that exhibits high tensile elongation and weather resistance, and exhibits excellent properties as a highly elastic paint for architecture, a brimmer for concrete structures, a waterproofing agent, etc.

Furthermore, when applied as a coating film waterproofing agent, it has an excellent balance between breaking strength and elongation, as well as good durability and water resistance, so deterioration such as blistering and peeling is improved compared to existing technologies.

Furthermore, when applied as an adhesive, it has excellent adhesive strength,
In particular, it is used in structural adhesives as an adhesive with a good balance between peel adhesive strength and shear adhesive strength.

When applying an alkyd-based paint onto a cured product made from the composition of the present invention, which is used for various purposes, the properties of the cured product are improved by applying the coating after the composition is almost completely cured. It is preferable because it is easy to paint because it can be applied onto objects, and there is no interruption in the supply of moisture necessary for curing of the oxyalkylene polymer (A) by the coating film. Once it has solidified, it can be painted.

The alkyd-based paint is not particularly limited, and may be a condensate of a polybasic acid (phthalic anhydride, maleic anhydride, etc.) and a polyhydric alcohol (glycerin, pentaerythritol, ethylene glycol, trimethylolethane, etc.), a fatty oil or So-called oil-modified alkyd resins modified with fatty acids (linseed oil, soybean oil, castor oil, safflower oil, etc.) and modified alkyd resins modified with various resins or vinyl monomers are the main materials used to form coatings. Alkyd resin face and alkyd resin enamel used in coatings for vehicles, aircraft, industrial, etc., and alkyd resin formulations used in coatings for architecture, iron bridges, ships, etc. It may be in any form, such as paint (also called synthetic resin compound paint), alkyd resin base paint used as a base paint for automobiles, machines, electrical products, furniture, etc. The effect is particularly remarkable in long-oil alkyd paints that are used for general purposes and have a large amount of drying oil.

Conventionally, when applying a cured alkyd paint that uses a combination of an oxyalkylene polymer (A) and a conventional low molecular weight plasticizer, the drying of the paint is significantly delayed, and sticky residue remains even after about a month has passed. Therefore, when applying an alkyd-based paint to the cured product, it has been said that the alkyd-based paint cannot be used unless it is first coated with a paint other than the alkyd-based paint (brimer).
By using the composition of the present invention, a conventional alkyd coating film can be formed on a cured product of a composition containing an oxyalkylene polymer (A) and a plasticizer by a conventional method.

Next, the composition of the present invention will be specifically explained based on Examples.

Synthesis Example 1 800 g of an oxypropylene polymer with an average molecular weight of 8,000 in which allyl ether groups have been introduced into 97% of all terminals was placed in a pressure-resistant reaction vessel equipped with a stirrer, and 1 methyldimethoxysilane was added.
Added 9g. Then, a chloroplatinic acid catalyst solution (H2PtC
After adding 0.34 ml of a solution in which 8.9 g of #-8H20 was dissolved in 18 ml of isopropyl alcohol and 160 ml of tetrahydrofuran, the mixture was reacted at 80° C. for 6 hours.

When the amount of residual hydrosilyl groups in the reaction solution was quantified by IR spectroscopy, it was found that almost no hydrosilyl groups remained. In addition, when the reactive silicon group was quantified by NMR method, (Cl30)281 (CH3) was found at the end of the molecule.
An oxypropylene polymer having approximately 1.7 CH2CH2C1120 groups per molecule was used instead.

Examples 1 to 4 and Comparative Examples 1 to 2 As shown in Table 1, the oxypropylene polymer (A) obtained in Synthesis Example 1, the oxyalkylene polymer (B) shown in Table 1, etc. A sheet with a thickness of 3 ml and 1 liter was made using the composition prepared by blending the ingredients, and after curing at room temperature for one day, alkyd paint (trade name: Rock Coat, manufactured by Rock Paint ■) was applied. The curing properties were then examined by touch after the number of days shown in Table 1.

The results are shown in Table 1.

In addition, in Table 1, ■ in the column of oxyalkylene polymer (B) is; ■ is Fin -5200, &/Rn-1,6, oxypropylene polymer with allyl ether groups at both ends, ■ is Lu 5100, L/= -1,1, proportion of components with MW 100O or less is 4%, terminal is an oxypropylene polymer having hydroxyl groups, and (2) is Mll-4000, L/Fin-1,1, an oxypropylene polymer having allyl ether groups at both ends.

■ is Fin-2400, Fiis/Rn= 1.1.
It is an oxypropylene polymer with allyl ether groups at both ends.

In addition, the numbers in the evaluation result column indicate the curing properties of the alkyd paint; 5 means that the applied paint is completely cured, 4 means that the applied paint is hardened but a little stickiness remains on the surface, and 3 means that the applied paint is cured completely When you put your finger on the surface, a little bit of paint sticks to your fingertips, 2. Although it has partially hardened, when you put your finger on the painted surface, the paint sticks to your fingertips. 1.
0 indicates that the applied paint has thickened, and 0 indicates that the applied paint has not changed at all (uncured).

Blank space below E] From the results in Table 1, when using oxypropylene with a terminal hydroxyl group blocked as in Example 1.2.4.5,
It is clear that the curing properties of alkyd paints are superior to those using conventional low-molecular plasticizers (dioctyl phthalate) and low-molecular f2 (R1+-3000) oxypropylene polymers with hydroxyl groups. It is.

It is also clear that when an oxypropylene polymer with a molecular ffl of 4000 or more is used as in Example 3, the curing properties of the alkyd paint are superior to those when a low molecular weight oxypropylene polymer is used. It is.

[Effect of the invention] The cured product obtained from the composition of the present invention containing an oxyalkylene polymer (A) and an oxyalkylene polymer (B) is coated with an alkyd paint under normal conditions. It can be dried and form a good alkyd paint film.

Claims (1)

[Scope of Claims] 1 (A) An oxyalkylene polymer having a hydroxyl group or a hydrolyzable group bonded to a silicon atom and having at least one silicon-containing group that can be crosslinked by forming a siloxane bond; B) At least one polymer selected from the group consisting of (i) an oxyalkylene polymer containing a hydroxyl group with a number average molecular weight of 4000 or more and (ii) an oxyalkylene polymer containing substantially no hydroxyl group. A curable composition containing. 2 (B) component ((B) (i) component and (B) (ii)
) component) of the oxyalkylene polymer whose weight average molecular weight (@M@_w)/number average molecular weight (@M@_n) is 1.
．． 5. The composition according to claim 1, which has a molecular weight of 5 or less. 3 (B) component ((B) (i) component and (B) (ii)
2. The composition according to claim 1, wherein the proportion of components having a molecular weight of 1000 or less in the oxyalkylene polymer (component) is 10% by weight or less. 4. The composition according to claim 1, wherein the oxyalkylene polymer as component (B)(i) has a number average molecular weight of 5,000 or more. 5. The composition according to claim 1, wherein the oxyalkylene polymer substantially free of hydroxyl groups, which is component (B)(i), is an allyl ether-terminated polymer. 6 (B) The number average molecular weight of the oxyalkylene polymer that is substantially free of hydroxyl groups and is component (i) is 1000.
The composition according to claim 1, which is the above.