JP6060876B2 - Low temperature curable coating composition and cured article thereof - Google Patents

Description

  The present invention relates to a low-temperature curable coating agent composition containing an organosiloxane obtained by hydrosilylation reaction of a hydrosilyl group-containing siloxane (organohydrogensiloxane) and an alkenyl group-containing alkoxysilane, and an organometallic catalyst, and a cured article thereof. .

  Silane compounds and siloxane compounds containing alkoxysilyl groups are widely used for paints and coating agents. In other words, these siloxane compounds containing alkoxysilyl groups can form a siloxane network by blending a curing catalyst to form a siloxane network at room temperature, making it easy to form a film with excellent heat resistance and weather resistance. Therefore, it is used in a wide range of fields from outdoor buildings to electronic components.

  Such an alkoxysilyl group-containing siloxane is generally produced by partially hydrolyzing an alkoxysilane (for example, Japanese Patent No. 2801660 (Patent Document 1), Japanese Patent Application Laid-Open No. 11-166052 (Patent Document). 2), refer to JP 2009-263576 A (Patent Document 3).

  However, it is considered that the most active alkoxy group is consumed during the hydrolysis reaction in the siloxane compound containing these alkoxy groups, and the alkoxy group having a slightly lower activity remains, so that the curing rate during the subsequent curing reaction Will fall. Furthermore, since the siloxane compound obtained by using such a method contains a large number of silanol groups, when alkali is allowed to act on the cured film, the film dissolves with the silanol group as a decomposition starting point. There is a point.

  In view of this, it has been carried out to obtain a siloxane compound containing an alkoxysilyl group by hydrosilylating a silicone compound containing a hydrosilyl group and a compound having both an olefin and an alkoxysilyl group (see, for example, (See Japanese Patent No. 6-271650 (Patent Document 4).) However, the siloxane compound obtained by using such a method also has insufficient alkali resistance, and no significant improvement was observed in terms of alkali resistance.

  In addition, a coating agent made of a low-molecular alkoxysilyl group-containing silane or siloxane compound such as tetramethoxysilane is excellent in reactivity, for example, is cured within 20 minutes in an environment of 25 ° C. and 50% RH, but the film is brittle. The mechanical properties, such as cracking during the curing, were not able to withstand use as a coating film.

Japanese Patent No. 2801660 Japanese Patent Laid-Open No. 11-166052 JP 2009-263576 A JP-A-6-271650

  The present invention has been made in view of the above circumstances, and provides a low-temperature curable coating agent composition and a cured article thereof having a good reactivity and a cured film excellent in alkali resistance and crack resistance. Objective.

  As a result of intensive studies to achieve the above object, the present inventors have (i) at least two hydrosilyl groups (Si—H groups) in one molecule and at least two specific carbons in one molecule. In one molecule obtained by reacting a siloxane compound (organohydrogensiloxane) containing a chain (an alkyl chain having 3 or more carbon atoms) with (ii) a silane compound containing an olefin moiety and an alkoxysilyl group A coating agent composition comprising an organosiloxane (A) containing a plurality of alkoxysilyl groups and a specific carbon chain (an alkyl chain having 3 or more carbon atoms) and an organometallic catalyst (B) exhibits low-temperature curability, Moreover, it discovered that the cured film had alkali resistance and crack resistance, and came to make this invention.

（式中、ａ及びｂは各々独立に２〜４の整数、Ｒ¹は炭素数３〜１０のアルキル基、Ｒ²及びＲ³は各々独立に炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基である。）
（ｂ）下記一般式（２）で示されるオルガノハイドロジェンシロキサン。

（式中、ａ及びｂは各々独立に２〜４の整数、Ｒ¹は炭素数３〜１０のアルキル基、Ｒ²及びＲ³及びＲ⁴は各々独立に炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基である。）
（ｃ）下記一般式（３）で示されるアルキルシランと下記一般式（４）で示されるヒドロシランの加水分解縮合物。

（式中、ｍは０、１又は２、Ｒ¹は炭素数３〜１０のアルキル基、Ｒ²は炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基、Ｘ¹はクロル原子又はＯＲ⁵で表されるアルコキシ基であり、Ｒ⁵は炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基である。）

（式中、ｎは０、１又は２、Ｒ³は炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基、Ｘ²はクロル原子又はＯＲ⁶で表されるアルコキシ基であり、Ｒ⁶は炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基である。）

（式中、ｐは０〜３の整数、ｑは０、１又は２、Ｒ⁷及びＲ⁸は各々独立に炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基である。）
〔２〕
オルガノハイドロジェンシロキサンが、上記一般式（１）で示される環状シロキサンであることを特徴とする〔１〕記載の低温硬化性コーティング剤組成物。
〔３〕
（Ａ）オルガノシロキサンが、下記一般式（６）で示されることを特徴とする〔１〕又は〔２〕記載の低温硬化性コーティング剤組成物。

（式中、Ｒ¹は炭素数３〜１０のアルキル基、ｒは２〜５の整数である。）
〔４〕
（Ａ）オルガノシロキサンが、下記一般式（７）で示されることを特徴とする〔３〕記載の低温硬化性コーティング剤組成物。

〔５〕
（Ｂ）有機金属触媒がチタンを含有することを特徴とする〔１〕〜〔４〕のいずれかに記載の低温硬化性コーティング剤組成物。
〔６〕
実質的に溶剤を含有しないことを特徴とする〔１〕〜〔５〕のいずれかに記載の低温硬化性コーティング剤組成物。
〔７〕
使用直前に（Ａ）オルガノシロキサンと（Ｂ）有機金属触媒とを混合することを特徴とする〔１〕〜〔６〕のいずれかに記載の低温硬化性コーティング剤組成物の製造方法。
〔８〕
〔１〕〜〔６〕のいずれかに記載の低温硬化性コーティング剤組成物の硬化物品。
That is, the present invention provides the following low-temperature curable coating composition and cured articles thereof.
[1]
(A) Obtained by subjecting an organohydrogensiloxane containing any one of the following organohydrogensiloxanes (a) to (c) to a hydrosilylation reaction with an alkenyl group-containing alkoxysilane represented by the following general formula (5). Organosiloxanes,
as well as,
(B) A low-temperature curable coating agent composition comprising an organometallic catalyst.
(A) Organohydrogensiloxane represented by the following general formula (1).

(In the formula, a and b are each independently an integer of 2 to 4, R ¹ is an alkyl group having 3 to 10 carbon atoms, R ² and R ³ are each independently an alkyl group having 1 to 3 carbon atoms or 6 carbon atoms. -10 aryl groups.)
(B) Organohydrogensiloxane represented by the following general formula (2).

(Wherein, a and b are each independently an integer of 2 to 4, R ¹ is an alkyl group having 3 to 10 carbon atoms, R ^2, R ³ and R ⁴ are each independently an alkyl group having 1 to 3 carbon atoms, or (It is an aryl group having 6 to 10 carbon atoms.)
(C) Hydrolysis condensate of alkylsilane represented by the following general formula (3) and hydrosilane represented by the following general formula (4).

Wherein m is 0, 1 or 2, R ¹ is an alkyl group having 3 to 10 carbon atoms, R ² is an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 10 carbon atoms, and X ¹ is a chloro atom. Or, it is an alkoxy group represented by OR ⁵ , and R ⁵ is an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 10 carbon atoms.)

Wherein n is 0, 1 or 2, R ³ is an alkyl group having 1 to ³ carbon atoms or an aryl group having 6 to 10 carbon atoms, X ² is a chloro atom or an alkoxy group represented by OR ⁶ ; R ⁶ is an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 10 carbon atoms.)

(In the formula, p is an integer of 0 to 3, q is 0, 1 or 2, and R ⁷ and R ⁸ are each independently an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 10 carbon atoms.)
[2]
The low-temperature curable coating composition according to [1], wherein the organohydrogensiloxane is a cyclic siloxane represented by the general formula (1).
[3]
(A) The low-temperature curable coating composition according to [1] or [2], wherein the organosiloxane is represented by the following general formula (6).

(In the formula, R ¹ is an alkyl group having 3 to 10 carbon atoms, and r is an integer of 2 to 5)
[4]
(A) The low-temperature curable coating composition according to [3], wherein the organosiloxane is represented by the following general formula (7).

[5]
(B) The low-temperature curable coating composition according to any one of [1] to [4], wherein the organometallic catalyst contains titanium.
[6]
The low-temperature curable coating agent composition according to any one of [1] to [5], which contains substantially no solvent.
[7]
Method for producing a low temperature curable coating composition according to any one of immediately before use (A) and the organosiloxane (B) mixing the organic metal catalyst, characterized in [1] to [6].
[8]
A cured article of the low-temperature curable coating agent composition according to any one of [1] to [ 6 ].

  According to the low-temperature curable coating agent composition of the present invention, an organohydrogensiloxane (i) that is a component of the low-temperature curable coating agent composition is obtained by reacting an olefin component and an alkoxysilyl group-containing silane compound (ii). Since the siloxane (A) contains a plurality of alkoxysilyl groups and a specific carbon chain (an alkyl chain having 3 or more carbon atoms) in one molecule, the coating agent composition of the present invention is applied onto a substrate, A cured film having excellent low-temperature curability when cured and excellent alkali resistance and crack resistance is provided. Moreover, when the said organosiloxane (A) has a cyclic siloxane structure, more remarkable low-temperature curability is expressed.

The low-temperature curable coating composition according to the present invention is
(A) Obtained by subjecting an organohydrogensiloxane containing any one of the following organohydrogensiloxanes (a) to (c) to a hydrosilylation reaction with an alkenyl group-containing alkoxysilane represented by the following general formula (5). Organosiloxanes,
as well as,
(B) An organometallic catalyst is contained, and the low temperature curable coating agent composition according to the present invention will be specifically described below.

[Organosiloxane (A)]
Organosiloxane contained in the coating agent composition of the present invention,
(I) an organohydrogensiloxane containing any one of the following organohydrogensiloxanes (a) to (c);
(A) an organohydrogensiloxane represented by the following general formula (1),
(B) an organohydrogensiloxane represented by the following general formula (2),
(C) hydrolysis condensate of alkylsilane represented by the following general formula (3) and hydrosilane represented by the following general formula (4);
(Ii) an alkenyl group-containing alkoxysilane represented by the following general formula (5);
Is hydrosilylated in the presence of a hydrosilylation reaction catalyst such as a platinum complex catalyst.

（式中、ａ及びｂは各々独立に２〜４の整数、Ｒ¹は炭素数３〜１０のアルキル基、Ｒ²及びＲ³は各々独立に炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基である。）

（式中、ａ及びｂは各々独立に２〜４の整数、Ｒ¹は炭素数３〜１０のアルキル基、Ｒ²及びＲ³及びＲ⁴は各々独立に炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基である。）

（式中、ｍは０、１又は２、Ｒ¹は炭素数３〜１０のアルキル基、Ｒ²は炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基、Ｘ¹はクロル原子又はＯＲ⁵で表されるアルコキシ基であり、Ｒ⁵は炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基である。）

（式中、ｎは０、１又は２、Ｒ³は炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基、Ｘ²はクロル原子又はＯＲ⁶で表されるアルコキシ基であり、Ｒ⁶は炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基である。）

（式中、ｐは０〜３の整数、ｑは０、１又は２、Ｒ⁷及びＲ⁸は各々独立に炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基である。）

(In the formula, a and b are each independently an integer of 2 to 4, R ¹ is an alkyl group having 3 to 10 carbon atoms, R ² and R ³ are each independently an alkyl group having 1 to 3 carbon atoms or 6 carbon atoms. -10 aryl groups.)

(Wherein, a and b are each independently an integer of 2 to 4, R ¹ is an alkyl group having 3 to 10 carbon atoms, R ^2, R ³ and R ⁴ are each independently an alkyl group having 1 to 3 carbon atoms, or (It is an aryl group having 6 to 10 carbon atoms.)

Wherein m is 0, 1 or 2, R ¹ is an alkyl group having 3 to 10 carbon atoms, R ² is an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 10 carbon atoms, and X ¹ is a chloro atom. Or, it is an alkoxy group represented by OR ⁵ , and R ⁵ is an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 10 carbon atoms.)

Wherein n is 0, 1 or 2, R ³ is an alkyl group having 1 to ³ carbon atoms or an aryl group having 6 to 10 carbon atoms, X ² is a chloro atom or an alkoxy group represented by OR ⁶ ; R ⁶ is an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 10 carbon atoms.)

(In the formula, p is an integer of 0 to 3, q is 0, 1 or 2, and R ⁷ and R ⁸ are each independently an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 10 carbon atoms.)

  In the method for producing an organosiloxane of the present invention, the reaction temperature is 15 to 150 ° C, preferably 40 to 130 ° C, more preferably 70 to 120 ° C. If the temperature is too low, the reaction does not proceed or the reaction rate is remarkably low, so that productivity may be lacking. On the other hand, when it exceeds 150 ° C., there is a possibility that thermal decomposition or unintended side reaction may occur.

  In the method for producing organosiloxane of the present invention, the reaction time is 10 minutes to 24 hours. The time may be a time such that the raw material is sufficiently consumed as the reaction proceeds, but it is preferably 1 to 10 hours, more preferably 2 to 7 hours. If the reaction time is too short, the consumption of the raw material may be insufficient, and if the reaction time is too long, the raw material has already been completely consumed, which may be an unnecessary process and production efficiency may be reduced.

  In the method for producing an organosiloxane of the present invention, a reaction solvent may be appropriately used. It is not particularly limited as long as it is non-reactive with the raw material and does not become a catalyst poison for the platinum complex used in the reaction, but typically, an aliphatic hydrocarbon solvent such as hexane or heptane, or an aromatic carbon such as toluene or xylene. Examples thereof include hydrogen solvents, alcohol solvents such as methanol, ethanol, propanol, and isopropanol, and ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone.

The organohydrogensiloxane (i) is an organohydrogensiloxane containing any one of the following organohydrogensiloxanes (a) to (c):
(A) an organohydrogensiloxane represented by the following general formula (1),
(B) an organohydrogensiloxane represented by the following general formula (2),
(C) There is no particular limitation as long as it is a hydrolyzed condensate of an alkylsilane represented by the following general formula (3) and a hydrosilane represented by the following general formula (4), and the siloxane bond is linear, branched or cyclic. However, it is preferably a cyclic siloxane represented by the following general formula (1) from the viewpoint of low-temperature curability described later and alkali resistance of the resulting coating film.

（式中、ａ及びｂは各々独立に２〜４の整数、Ｒ¹は炭素数３〜１０のアルキル基、Ｒ²及びＲ³は各々独立に炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基である。）

（式中、ａ及びｂは各々独立に２〜４の整数、Ｒ¹は炭素数３〜１０のアルキル基、Ｒ²及びＲ³及びＲ⁴は各々独立に炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基である。）

（式中、ｍは０、１又は２、Ｒ¹は炭素数３〜１０のアルキル基、Ｒ²は炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基、Ｘ¹はクロル原子又はＯＲ⁵で表されるアルコキシ基であり、Ｒ⁵は炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基である。）

（式中、ｎは０、１又は２、Ｒ³は炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基、Ｘ²はクロル原子又はＯＲ⁶で表されるアルコキシ基であり、Ｒ⁶は炭素数１〜３のアルキル基又は炭素数６〜１０のアリール基である。）

(In the formula, a and b are each independently an integer of 2 to 4, R ¹ is an alkyl group having 3 to 10 carbon atoms, R ² and R ³ are each independently an alkyl group having 1 to 3 carbon atoms or 6 carbon atoms. -10 aryl groups.)

(Wherein, a and b are each independently an integer of 2 to 4, R ¹ is an alkyl group having 3 to 10 carbon atoms, R ^2, R ³ and R ⁴ are each independently an alkyl group having 1 to 3 carbon atoms, or (It is an aryl group having 6 to 10 carbon atoms.)

Wherein m is 0, 1 or 2, R ¹ is an alkyl group having 3 to 10 carbon atoms, R ² is an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 10 carbon atoms, and X ¹ is a chloro atom. Or, it is an alkoxy group represented by OR ⁵ , and R ⁵ is an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 10 carbon atoms.)

Wherein n is 0, 1 or 2, R ³ is an alkyl group having 1 to ³ carbon atoms or an aryl group having 6 to 10 carbon atoms, X ² is a chloro atom or an alkoxy group represented by OR ⁶ ; R ⁶ is an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 10 carbon atoms.)

  Specific examples of the organohydrogensiloxane (1) include 1,3,5,7-tetramethyl-dipropylcyclotetrasiloxane, 1,3,5,7-tetramethyl-dibutylcyclotetrasiloxane, , 3,5,7-tetramethyl-dipentylcyclotetrasiloxane, 1,3,5,7-tetramethyl-dihexylcyclotetrasiloxane, 1,3,5,7-tetramethyl-diheptylcyclotetrasiloxane, 3,5,7-tetramethyl-dioctylcyclotetrasiloxane, 1,3,5,7-tetramethyl-dinonylcyclotetrasiloxane, 1,3,5,7-tetramethyl-didecylcyclotetrasiloxane, 1, 3,5,7,9-pentamethyl-dipropylcyclopentasiloxane, 1,3,5,7,9-pentamethy -Dibutylcyclopentasiloxane, 1,3,5,7,9-pentamethyl-dipentylcyclopentasiloxane, 1,3,5,7,9-pentamethyl-dihexylcyclopentasiloxane, 1,3,5,7,9- Pentamethyl-diheptylcyclopentasiloxane, 1,3,5,7,9-pentamethyl-dioctylcyclopentasiloxane, 1,3,5,7,9-pentamethyl-dinonylcyclopentasiloxane, 1,3,5,7 , 9-pentamethyl-didecylcyclopentasiloxane, 1,3,5,7,9-pentamethyl-tripropylcyclopentasiloxane, 1,3,5,7,9-pentamethyl-tributylcyclopentasiloxane, 1,3,5 5,7,9-pentamethyl-tripentylcyclopentasiloxane, 1,3,5,7,9 Pentamethyl-trihexylcyclopentasiloxane, 1,3,5,7,9-pentamethyl-triheptylcyclopentasiloxane, 1,3,5,7,9-pentamethyl-trioctylcyclopentasiloxane, 1,3,5, Examples include 7,9-pentamethyl-trinonylcyclopentasiloxane and 1,3,5,7,9-pentamethyl-trisdecylcyclopentasiloxane, but are not limited to those exemplified here. There is no problem even if the number of units of the cyclic siloxane has a distribution, but more preferred is a siloxane tetramer that is thermodynamically stable and easy to produce a raw siloxane.

  Specific examples of the organohydrogensiloxane (2) include polysiloxanes composed of methylsiloxane units and methylpropylsiloxane units, polysiloxanes composed of methylsiloxane units and methylbutylsiloxane units, and methylsiloxane units. Polysiloxane composed of methylpentylsiloxane units, polysiloxane composed of methylsiloxane units and methylhexylsiloxane units, polysiloxane composed of methylsiloxane units and methylheptylsiloxane units, methylsiloxane units and methyloctylsiloxane units Polysiloxane consisting of polysiloxane, methylsiloxane unit and methylnonylsiloxane unit Sun, although polysiloxanes and the like composed of methylsiloxane units and methyl decyl siloxane units, not limited to those exemplified here.

  The organohydrogensiloxane can also be prepared by a cohydrolysis condensation reaction of alkylsilane (3) and hydrosilane (4). A known method can be used as the hydrolysis-condensation method, and it is not particularly limited. However, a catalyst for hydrolysis / condensation reaction and water are added to a mixture of alkylsilane (3) and hydrosilane (4). And can be prepared by co-condensation.

  Specific examples of the alkylsilane (3) include propyltrimethoxysilane, butyltrimethoxysilane, pentyltrimethoxysilane, hexyltrimethoxysilane, heptyltrimethoxysilane, octyltrimethoxysilane, nonyltrimethoxysilane, decyl. Trimethoxysilane, propylmethyldimethoxysilane, butylmethyldimethoxysilane, pentylmethyldimethoxysilane, hexylmethyldimethoxysilane, heptylmethyldimethoxysilane, octylmethyldimethoxysilane, nonylmethyldimethoxysilane, decylmethyldimethoxysilane, propylphenyldimethoxysilane, butyl Phenyldimethoxysilane, pentylphenyldimethoxysilane, hexylphenyldimethoxysilane, heptylphenyldimethyl Xysilane, octylphenyldimethoxysilane, nonylphenyldimethoxysilane, decylphenyldimethoxysilane, propyltriethoxysilane, butyltriethoxysilane, pentyltriethoxysilane, hexyltriethoxysilane, heptyltriethoxysilane, octyltriethoxysilane, nonyltriethoxy Silane, decyltriethoxysilane, propylmethyldiethoxysilane, butylmethyldiethoxysilane, pentylmethyldiethoxysilane, hexylmethyldiethoxysilane, heptylmethyldiethoxysilane, octylmethyldiethoxysilane, nonylmethyldiethoxysilane, decyl Methyldiethoxysilane, propylphenyldiethoxysilane, butylphenyldiethoxysilane, pentylphenyldie Xysilane, hexylphenyldiethoxysilane, heptylphenyldiethoxysilane, octylphenyldiethoxysilane, nonylphenyldiethoxysilane, decylphenyldiethoxysilane, propyltrichlorosilane, butyltrichlorosilane, pentyltrichlorosilane, hexyltrichlorosilane, heptyltri Chlorosilane, octyltrichlorosilane, nonyltrichlorosilane, decyltrichlorosilane, propylmethyldichlorosilane, butylmethyldichlorosilane, pentylmethyldichlorosilane, hexylmethyldichlorosilane, heptylmethyldichlorosilane, octylmethyldichlorosilane, nonylmethyldichlorosilane, decyl Methyldichlorosilane, propylphenyldichlorosilane, butylphenyldichloro Examples include, but are not limited to, rosilane, pentylphenyldichlorosilane, hexylphenyldichlorosilane, heptylphenyldichlorosilane, octylphenyldichlorosilane, nonylphenyldichlorosilane, decylphenyldichlorosilane, and the like.

  Specific examples of the hydrosilane (4) include trimethoxysilane, methyldimethoxysilane, phenyldimethoxysilane, triethoxysilane, methyldiethoxysilane, phenyldiethoxysilane, trichlorosilane, methyldichlorosilane, phenyldichlorosilane and the like. However, it is not limited to those exemplified here.

  Among the above organohydrogensiloxanes, 1,3,5,7-tetramethyl-dipropylcyclotetrasiloxane, 1 from the viewpoint of easy availability of raw materials, low-temperature curability described later, and alkali resistance of the resulting coating film, 3,5,7,9-pentamethyl-dipropylcyclopentasiloxane, 1,3,5,7,9-pentamethyl-tripropylcyclopentasiloxane, polysiloxane composed of methylsiloxane units and methylpropylsiloxane units. 1,3,5,7-tetramethyl-dipropylcyclotetrasiloxane is most preferred.

The alkenyl group-containing alkoxysilane (ii) is represented by the following general formula (5).

In the general formula (5), R ⁷ and R ⁸ are each independently an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 10 carbon atoms, and the alkyl group is linear, branched or cyclic. Typically, a methyl group, an ethyl group, a propyl group, an isopropyl group, etc. are mentioned as an alkyl group, and a phenyl group, a naphthyl group, etc. are mentioned as an aryl group. Among them, a methyl group and an ethyl group are preferable, and a methyl group is particularly preferable from the viewpoint of ease of raw material production and hydrolyzability.

  In the formula (5), p is an integer of 0 to 3, preferably 0 to 1, q is 0, 1 or 2, but an organohydrogensiloxane and an alkenyl group-containing alkoxysilane are present in a platinum complex catalyst. From the viewpoint of the hydrolyzability of the organosiloxane obtained by hydrosilylation below, and the alkali resistance of a cured article formed by applying a coating composition containing the organosiloxane, q is preferably 0, and p More preferably, 0 is 0 and q is 0.

  The use ratio of the reaction raw material in the present invention is preferably 0.9 to 1.5 mol of an alkenyl group-containing alkoxysilane with respect to 1 mol of Si-H group in the organohydrogensiloxane, more preferably 1.1 to 1. 3 moles. If the amount is less than 0.9 mol, the raw material consumption may be insufficient. If the amount exceeds 1.5 mol, unreacted alkenyl group-containing alkoxysilane, which is a high-boiling component, is completely removed from the product by distillation under reduced pressure. It may be difficult to remove, or an unnecessary process such as requiring a high pressure reduction condition for complete removal may occur, resulting in a decrease in production efficiency.

  The hydrosilylation reaction catalyst in the present invention is preferably platinum (Pt) and / or a complex compound having platinum (Pt) as a central metal, which is known as a known technique. Specifically, an alcohol solution of chloroplatinic acid, a 1,3-divinyltetramethyldisiloxane complex of chloroplatinic acid, a compound obtained by neutralizing the complex, and the oxidation number of the central metal are Pt (II) or Pt ( 0) 1,3-divinyltetramethyldisiloxane complex. Preferably, the oxidation number of the central metal is a complex other than Pt (IV) from the viewpoint of addition site selectivity, and Pt (0) and Pt (II) are particularly preferable.

  The amount of the hydrosilylation reaction catalyst used in the present invention is not particularly limited as long as the catalytic effect of the hydrosilylation reaction is expressed, but is preferably 0.000001 to 1 mol with respect to 1 mol of the alkenyl group-containing alkoxysilane. More preferably, it is 0.0001-0.01 mol. When the amount is less than 0.000001 mol, there is a possibility that a sufficient catalytic effect may not be exhibited. When the amount is more than 1 mol, the effect is saturated, and the production cost may be increased, which may be uneconomical.

  In the present invention, specific examples of the organosiloxane obtained by hydrosilylating the organohydrogensiloxane and the alkenyl group-containing alkoxysilane in the presence of a hydrosilylation reaction catalyst such as a platinum complex catalyst include bis-trimethoxysilyl. Ethyl-1,3,5,7-tetramethyl-dipropylcyclotetrasiloxane, bis-methyldimethoxysilylethyl-1,3,5,7-tetramethyl-dipropylcyclotetrasiloxane, bis-triethoxysilylethyl- 1,3,5,7-tetramethyl-dipropylcyclotetrasiloxane, bis-trimethoxysilylpropyl-1,3,5,7-tetramethyl-dipropylcyclotetrasiloxane, bis-methyldimethoxysilylpropyl-1, 3,5,7-tetramethyl Dipropylcyclotetrasiloxane, bis-triethoxysilylpropyl-1,3,5,7-tetramethyl-dipropylcyclotetrasiloxane, bis-trimethoxysilylethyl-1,3,5,7-tetramethyl-dibutylcyclo Tetrasiloxane, bis-triethoxysilylethyl-1,3,5,7-tetramethyl-dibutylcyclotetrasiloxane, bis-trimethoxysilylpropyl-1,3,5,7-tetramethyl-dibutylcyclotetrasiloxane, bis -Triethoxysilylpropyl-1,3,5,7-tetramethyl-dibutylcyclotetrasiloxane, bis-trimethoxysilylethyl-1,3,5,7-tetramethyl-dipentylcyclotetrasiloxane, bis-triethoxysilyl Ethyl-1,3,5,7-tetrame Ru-dipentylcyclotetrasiloxane, bis-trimethoxysilylpropyl-1,3,5,7-tetramethyl-dipentylcyclotetrasiloxane, bis-triethoxysilylpropyl-1,3,5,7-tetramethyl-dipentylcyclo Tetrasiloxane, bis-trimethoxysilylethyl-1,3,5,7-tetramethyl-dihexylcyclotetrasiloxane, bis-triethoxysilylethyl-1,3,5,7-tetramethyl-dihexylcyclotetrasiloxane, bis -Trimethoxysilylpropyl-1,3,5,7-tetramethyl-dihexylcyclotetrasiloxane, bis-triethoxysilylpropyl-1,3,5,7-tetramethyl-dihexylcyclotetrasiloxane, bis-trimethoxysilyl Ethyl-1,3,5 7-tetramethyl-diheptylcyclotetrasiloxane, bis-triethoxysilylethyl-1,3,5,7-tetramethyl-diheptylcyclotetrasiloxane, bis-trimethoxysilylpropyl-1,3,5,7- Tetramethyl-diheptylcyclotetrasiloxane, bis-triethoxysilylpropyl-1,3,5,7-tetramethyl-diheptylcyclotetrasiloxane, bis-trimethoxysilylethyl-1,3,5,7-tetramethyl Dioctylcyclotetrasiloxane, bis-triethoxysilylethyl-1,3,5,7-tetramethyl-dioctylcyclotetrasiloxane, bis-trimethoxysilylpropyl-1,3,5,7-tetramethyl-dioctylcyclotetra Siloxane, bis-triethoxysilylpropyl 1,3,5,7-tetramethyl-dioctylcyclotetrasiloxane, bis-trimethoxysilylethyl-1,3,5,7-tetramethyl-dinonylcyclotetrasiloxane, bis-triethoxysilylethyl-1,3 , 5,7-tetramethyl-dinonylcyclotetrasiloxane, bis-trimethoxysilylpropyl-1,3,5,7-tetramethyl-dinonylcyclotetrasiloxane, bis-triethoxysilylpropyl-1,3,5 , 7-tetramethyl-dinonylcyclotetrasiloxane, bis-trimethoxysilylethyl-1,3,5,7-tetramethyl-didecylcyclotetrasiloxane, bis-triethoxysilylethyl-1,3,5,7 -Tetramethyl-didecylcyclotetrasiloxane, bis-trimethoxysilylpropyl 1,3,5,7-tetramethyl-didecylcyclotetrasiloxane, bis-triethoxysilylpropyl-1,3,5,7-tetramethyl-decylcyclotetrasiloxane, tris-trimethoxysilylethyl-1, 3,5,7,9-pentamethyl-dipropylcyclopentasiloxane, tris-trimethoxysilylpropyl-1,3,5,7,9-pentamethyl-dipropylcyclopentasiloxane, bis-trimethoxysilylethyl-1, 3,5,7,9-pentamethyl-tripropylcyclopentasiloxane, bis-trimethoxysilylpropyl-1,3,5,7,9-pentamethyl-tripropylcyclopentasiloxane, from methylsiloxane units and methylpropylsiloxane units Consists of polysiloxane and vinyl Hydrosilylation reaction product with limethoxysilane, hydrosilylation reaction product of polysiloxane composed of methylsiloxane unit and methylpropylsiloxane unit and allyltrimethoxysilane, cohydrolysis of propyltrimethoxysilane and trimethoxysilane Although a condensation reaction product etc. are mentioned, it is not restricted to what was illustrated here. Among these, bis-trimethoxysilylethyl-1,3,5,7-tetramethyl-dipropylcyclotetrasiloxane, from the viewpoint of easy availability of raw materials, low-temperature curability described later, and alkali resistance of the resulting coating film, Tris-trimethoxysilylethyl-1,3,5,7,9-pentamethyl-dipropylcyclopentasiloxane, bis-trimethoxysilylethyl-1,3,5,7,9-pentamethyl-tripropylcyclopentasiloxane, Hydrosilylation reaction product of polysiloxane composed of methylsiloxane unit and methylpropylsiloxane unit and vinyltrimethoxysilane, cohydrolysis condensation reaction product of propyltrimethoxysilane and trimethoxysilane are preferred, and bis-trimethoxy Silylethyl-1,3,3 , 7-tetramethyl - dipropyl cyclotetrasiloxane is most preferred.

The organosiloxane (A) contained in the coating agent composition of the present invention has a cyclic siloxane skeleton represented by the following general formula (6) as a structural unit and a plurality of alkoxysilyl groups and a specific carbon chain (in one molecule). When it contains an alkyl chain having 3 or more carbon atoms, it exhibits particularly good low-temperature curability, alkali resistance, and crack resistance.

In the general formula (6), R ¹ represents an alkyl group having 3 to 10 carbon atoms, and r represents the carbon number of the carbon chain spacer. r may be in the range of an integer of 2 to 5, and particularly in the range of an integer of 2 to 3, from the viewpoint of easy availability of raw materials, low-temperature curability described later, and alkali resistance of the resulting coating film. R ¹ is preferably a propyl group and r is more preferably 2.

That is, (A) a particularly good low-temperature curability and alkali resistance when the organosiloxane structural unit contains a cyclic siloxane skeleton represented by the following general formula (7) and a plurality of alkoxysilyl groups and propyl groups in one molecule. Demonstrate crack resistance.

[(B) Organometallic catalyst]
The organometallic catalyst contained in the coating agent composition of the present invention is not particularly limited as long as it is a curing catalyst used for curing a general moisture condensation curable composition. As the organometallic catalyst, a titanium-based, aluminum-based, tin-based, zirconium-based or bismuth-based catalyst can be suitably used. Specific examples of titanium-based catalysts include tetraalkyl orthotitanates such as tetrabutyl orthotitanate, tetramethyl orthotitanate, tetraethyl orthotitanate and tetrapropyl orthotitanate, and partial hydrolysates thereof. Examples of the aluminum catalyst include aluminum trihydroxide, aluminum alcoholate, aluminum acylate, aluminum acylate salt, aluminosiloxy compound, aluminum metal chelate compound and the like. Examples of the tin catalyst include dioctyltin dioctate and dioctyltin dilaurate, but are not limited to those exemplified here. Of these, tetraalkyl orthotitanate having higher reactivity is preferable, and tetrapropyl orthotitanate and tetrabutyl orthotitanate are most preferable.

  The addition amount of the organometallic catalyst is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of (A) the organosiloxane.

  The low-temperature fast-curing coating agent composition of the present invention is a mixture of (A) an organosiloxane and (B) an organometallic catalyst, but preferably contains substantially no solvent. Here, “substantially” means that the solvent contained in the composition is 1% by mass or less, particularly 0.1% by mass or less. The solvent here is intentionally included in the low-temperature fast-curing coating agent composition such as (A) the reaction solvent used in the production of the organosiloxane, which could not be completely removed by distillation under reduced pressure. It refers to those that are not added ingredients.

  The coating agent composition of the present invention is applied to the surface of a solid substrate to give a coated solid substrate as a cured article. The coated solid substrate is not particularly limited, and usable solid substrates are often polycarbonates and polycarbonate blends, acrylic resins including poly (methyl methacrylate), poly (ethylene terephthalate), and the like. And polyesters such as poly (butylene terephthalate), polyamides, polyimides, acrylonitrile-styrene copolymers, styrene-acrylonitrile-butadiene copolymers, polyvinyl chloride, polystyrene, blends of polystyrene and polyphenylene ether, cellulose acetate butyrate Polymer substrates such as rate and polyethylene are included. In addition, solid substrates include metal substrates, paint-coated surfaces, glass, ceramics, concrete, slate plates and textiles. However, the coating agent composition of the present invention is preferably used for coating an acrylic resin.

When the coating agent composition is applied to a substrate, curing proceeds at a low temperature curability, that is, at 25 ° C. and 50% RH within 20 minutes, and a corresponding cured article is obtained. In particular, when a cyclic siloxane containing a plurality of alkoxysilyl groups and propyl groups in one molecule represented by the following general formula (7) is used as the organosiloxane (A) contained in the composition, 15 minutes at the same temperature. Curing progresses within the range, and a cured article with better alkali resistance can be obtained without causing appearance defects such as repellency, cracks associated with curing, and peeling from the substrate.
Here, “curing” means that the surface of the coating film is tack-free (a dry state of the touch, a state where the curing has progressed and the coating film does not adhere to the fingertip).

  Moreover, since it will harden | cure in a comparatively short time if it mixes, it is good to mix (A) organosiloxane and (B) organometallic catalyst just before use to make a coating agent composition.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the examples shown below.

[Example 1]
In Example 1, 1,3,5,7-tetramethyl-dipropylcyclotetrasiloxane was used as the organohydrogensiloxane and vinyltrimethoxysilane was used as the alkenyl group-containing alkoxysilane, and synthesis was performed based on the following formulation.
In a separable flask equipped with a stirrer, reflux condenser, dropping funnel and thermometer, 575 parts by weight of vinyltrimethoxysilane, 333 parts by weight of toluene, platinum complex (1,3-divinyltetramethyldisiloxane of Pt (0)) The toluene solution of (complex) was stirred and mixed in an amount corresponding to 0.00002 mol (in terms of platinum) of platinum complex with respect to 1 mol of Si-H group. Thereafter, when the internal temperature reached 75 ° C. by heating, 600 parts by mass of 1,3,5,7-tetramethyl-dipropylcyclotetrasiloxane (1.1 mol of alkenyl group to 1 mol of Si—H group) The corresponding amount) was added dropwise over 2 hours. At the same time as the dropping, a reaction occurred, an exotherm was generated, and the reaction solution temperature gradually increased from 75 ° C. Therefore, the heating was stopped, and the dropping was continued while adjusting the reaction solution temperature not to exceed 90 ° C. After completion of the dropwise addition, the reaction solution was aged for 1 hour while being heated to an internal temperature of 90 ° C., and then IR and hydrogen gas generation amount of the reaction solution were measured to confirm that no Si—H groups remained. Then, the corresponding organosiloxane was obtained by removing toluene by depressurizing distillation (80 degreeC, 5 mmHg).
100 parts by mass of the obtained organosiloxane and 5 parts by mass of tetrabutyl orthotitanate as an organometallic catalyst were uniformly mixed and defoamed using a stirrer to obtain a coating agent composition.

[Example 2]
In Example 2, the same procedure as in Example 1 was used, except that 5 parts by mass of di-n-butoxy (ethyl acetoacetate) aluminum was used as the organometallic catalyst instead of 5 parts by mass of tetrabutyl orthotitanate in Example 1. A composition was prepared.

[Example 3]
In Example 3, instead of 600 parts by mass of 1,3,5,7-tetramethyl-dipropylcyclotetrasiloxane of Example 1 as organohydrogensiloxane, 1,3,5,7-tetramethyl-dioctylcyclotetra A composition was prepared in the same procedure as in Example 1 except that 820 parts by mass of siloxane (an amount corresponding to 1.1 mol of an alkenyl group with respect to 1 mol of Si-H group) was used.

[Example 4]
In Example 4, instead of 600 parts by mass of 1,3,5,7-tetramethyl-dipropylcyclotetrasiloxane of Example 1 as organohydrogensiloxane, 1,3,5,7,9-pentamethyl-tripropyl A composition was prepared in the same manner as in Example 1 except that 753 parts by mass of cyclopentasiloxane (amount corresponding to 1.1 mol of alkenyl group with respect to 1 mol of Si-H group) was used.

[Example 5]
In Example 5, instead of 600 parts by mass of 1,3,5,7-tetramethyl-dipropylcyclotetrasiloxane of Example 1 as the organohydrogensiloxane, the average structural formula is represented by M ₂ ^DH ₂ D ^Pr ₂ . Chain siloxane (wherein M represents a terminal trimethylsiloxane unit, D ^H represents a methyl siloxane unit, D ^Pr represents a methyl propyl siloxane unit, and each number represents the number of components of the corresponding unit. The composition was prepared in the same procedure as in Example 1 except that 860 parts by mass (the amount corresponding to 1.1 mol of the alkenyl group relative to 1 mol of the Si—H group) was used.

[Example 6]
In Example 6, instead of 600 parts by mass of 1,3,5,7-tetramethyl-dipropylcyclotetrasiloxane of Example 1 as organohydrogensiloxane, a cohydrolysis condensation reaction of propyltrimethoxysilane and trimethoxysilane A composition was prepared in the same procedure as in Example 1 except that 525 parts by mass of the product (amount corresponding to 1.1 mol of alkenyl group relative to 1 mol of Si-H group) was used.

[Comparative Example 1]
In Comparative Example 1, 100 parts by mass of N-2- (aminoethyl) -3-aminopropyltrimethoxysilane and 5 parts by mass of tetrabutyl orthotitanate as in Example 1 as an organometallic catalyst were uniformly used with a stirrer. And defoamed to obtain a coating composition.

[Comparative Example 2]
In Comparative Example 2, 100 parts by mass of tetramethoxysilane and 5 parts by mass of tetrabutyl orthotitanate same as Example 1 as an organometallic catalyst were uniformly mixed and defoamed using a stirrer to obtain a coating agent composition. It was.

[Comparative Example 3]
In Comparative Example 3, 100 parts by mass of trimethoxymethylsilane and 5 parts by mass of tetrabutyl orthotitanate same as Example 1 as an organometallic catalyst were uniformly mixed and defoamed using a stirrer to obtain a coating composition. Obtained.

[Comparative Example 4]
In Comparative Example 4, 100 parts by mass of a partially hydrolyzed oligomer of trimethoxymethylsilane and 5 parts by mass of tetrabutyl orthotitanate as in Example 1 as an organometallic catalyst were uniformly mixed and defoamed using a stirrer. A coating agent composition was obtained.

[Comparative Example 5]
In Comparative Example 5, instead of 600 parts by mass of 1,3,5,7-tetramethyl-dipropylcyclotetrasiloxane of Example 1 as organohydrogensiloxane, the average structural formula is represented by D ₂ ^DH _2. Cyclic siloxane (where D means a dimethylsiloxane unit, ^DH means a methylsiloxane unit, and each number means the number of components of the corresponding unit) 475 parts by mass (one mole of Si-H group) A composition was prepared in the same manner as in Example 1 except that the amount of alkenyl group corresponding to 1.1 mol was used.

[Comparative Example 6]
In Comparative Example 6, 1,3,5,7-tetramethylcyclotetrasiloxane 212 was substituted for 600 parts by mass of 1,3,5,7-tetramethyl-dipropylcyclotetrasiloxane of Example 1 as the organohydrogensiloxane. A composition was prepared in the same procedure as in Example 1 except that the amount of the alkenyl group was 1.1 mol relative to 1 mol of the Si-H group.

[Comparative Example 7]
In Comparative Example 7, instead of 600 parts by mass of 1,3,5,7-tetramethyl-dipropylcyclotetrasiloxane of Example 1 as organohydrogensiloxane, the average structural formula is represented by M ₂ ^DH ₃ D ₁ . Chain siloxane (wherein M represents a terminal trimethylsiloxane unit, ^DH represents a methylsiloxane unit, D represents a dimethylsiloxane unit, and each number represents the number of components of the corresponding unit. The composition was prepared in the same procedure as in Example 1 except that 490 parts by mass (the amount corresponding to 1.1 mol of the alkenyl group relative to 1 mol of the Si—H group) was used.

  The compositions obtained in Examples 1 to 6 and Comparative Examples 1 to 7 were subjected to bar coater no. 14 was applied to an acrylic plate (manufactured by Mitsubishi Rayon Co., Ltd., Acrylite EX # 001 colorless 2 mm thickness) and subjected to various evaluations described later.

[Low-temperature curability test]
After applying the composition described in Examples 1 to 6 and Comparative Examples 1 to 7 to the base material (acrylic plate) by the above application method, tack-free time (touch drying time, curing proceeds and the coating film is applied to the fingertip Time until no longer adhered) was confirmed. The evaluation results are shown in Tables 1 and 2 below.

[Alkali resistance]
The alkali resistance of the cured film obtained by applying the composition described in Examples 1 to 6 and Comparative Examples 1 to 7 to the base material (acrylic plate) and curing by the above coating method is obtained using an aqueous sodium hydroxide solution. The spot test was confirmed. As a specific test method, after coating, it was allowed to stand for one week under the conditions of 25 ° C. and 50% RH and sufficiently cured, and then a drop of a 10% by mass sodium hydroxide aqueous solution was dropped on the film, for a total of five places. This was carried out and allowed to stand at room temperature (25 ° C.) for 1 hour, and then rinsed with water and dried to visually confirm the dissolution of the cured film and traces of water droplets. When no trace of water droplets was observed, it was evaluated as “◯” as having excellent alkali resistance. When traces of water droplets were observed, or when the film was dissolved, it was evaluated as “x”. The evaluation results are shown in Tables 1 and 2 below.

[Appearance evaluation]
The external appearance of the cured film obtained by apply | coating and hardening | curing this composition as described in Examples 1-6 and Comparative Examples 1-7 on a base material (acrylic board) with the said application | coating method was confirmed. Specifically, attention was focused on appearance defects such as cracks associated with curing and the presence or absence of peeling from the substrate (denoted as “crack resistance” in the table). When these appearance defects were not observed at all, it was evaluated as “◯” as having excellent appearance. When these appearance defects were slightly observed, it was evaluated as “Δ”. When these appearance defects were observed remarkably, it was evaluated as “x”. The evaluation results are shown in Tables 1 and 2 below.

  The above results demonstrate that when the compositions described in Examples 1-6 are applied to a substrate, low temperature curability, i.e., curing proceeds within 20 minutes at 25 ° C. and 50% RH. . In particular, as in Example 1, when the organosiloxane contained in the composition was a cyclic siloxane containing a plurality of alkoxysilyl groups and propyl groups in one molecule represented by the general formula (7), the same It indicates that curing proceeds within 15 minutes at a temperature, and a cured article having further excellent alkali resistance can be obtained without causing appearance defects such as repelling, cracks associated with curing, and peeling from the substrate. Here, “curing” means that the surface of the coating film is tack-free (a dry state of the touch, a state where the curing has progressed and the coating film does not adhere to the fingertip).

  Although the present invention has been described with the embodiment, the present invention is not limited to the embodiment, and other embodiments, additions, changes, deletions, and the like can be conceived by those skilled in the art. As long as the effects of the present invention are exhibited in any aspect, they are included in the scope of the present invention.

Claims (8)

(A) Obtained by subjecting an organohydrogensiloxane containing any one of the following organohydrogensiloxanes (a) to (c) to a hydrosilylation reaction with an alkenyl group-containing alkoxysilane represented by the following general formula (5). Organosiloxanes,
as well as,
(B) A low-temperature curable coating agent composition comprising an organometallic catalyst.
(A) Organohydrogensiloxane represented by the following general formula (1).

(In the formula, a and b are each independently an integer of 2 to 4, R ¹ is an alkyl group having 3 to 10 carbon atoms, R ² and R ³ are each independently an alkyl group having 1 to 3 carbon atoms or 6 carbon atoms. -10 aryl groups.)
(B) Organohydrogensiloxane represented by the following general formula (2).

(Wherein, a and b are each independently an integer of 2 to 4, R ¹ is an alkyl group having 3 to 10 carbon atoms, R ^2, R ³ and R ⁴ are each independently an alkyl group having 1 to 3 carbon atoms, or (It is an aryl group having 6 to 10 carbon atoms.)
(C) Hydrolysis condensate of alkylsilane represented by the following general formula (3) and hydrosilane represented by the following general formula (4).

Wherein m is 0, 1 or 2, R ¹ is an alkyl group having 3 to 10 carbon atoms, R ² is an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 10 carbon atoms, and X ¹ is a chloro atom. Or, it is an alkoxy group represented by OR ⁵ , and R ⁵ is an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 10 carbon atoms.)

Wherein n is 0, 1 or 2, R ³ is an alkyl group having 1 to ³ carbon atoms or an aryl group having 6 to 10 carbon atoms, X ² is a chloro atom or an alkoxy group represented by OR ⁶ ; R ⁶ is an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 10 carbon atoms.)

(In the formula, p is an integer of 0 to 3, q is 0, 1 or 2, and R ⁷ and R ⁸ are each independently an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 10 carbon atoms.)   The low-temperature curable coating composition according to claim 1, wherein the organohydrogensiloxane is a cyclic siloxane represented by the general formula (1). (A) Organosiloxane is shown by following General formula (6), The low-temperature-curable coating agent composition of Claim 1 or 2 characterized by the above-mentioned.

(In the formula, R ¹ is an alkyl group having 3 to 10 carbon atoms, and r is an integer of 2 to 5) (A) Organosiloxane is shown by following General formula (7), The low-temperature-curable coating agent composition of Claim 3 characterized by the above-mentioned.

  (B) The low-temperature curable coating composition according to any one of claims 1 to 4, wherein the organometallic catalyst contains titanium.   The low-temperature curable coating composition according to any one of claims 1 to 5, which contains substantially no solvent. Method for producing a low temperature curable coating composition of any one of claims 1 to 6, characterized by mixing immediately before use (A) and the organosiloxane (B) an organometallic catalyst. A cured article of the low-temperature curable coating agent composition according to any one of claims 1 to 6 .