AU2017257120B2

AU2017257120B2 - Curable composition

Info

Publication number: AU2017257120B2
Application number: AU2017257120A
Authority: AU
Inventors: Manabu Kirino
Original assignee: ThreeBond Co Ltd
Current assignee: ThreeBond Co Ltd
Priority date: 2016-04-26
Filing date: 2017-03-29
Publication date: 2020-12-17
Anticipated expiration: 2037-03-29
Also published as: BR112018071756A8; JPWO2017187874A1; AU2017257120A1; KR20190003482A; MY187352A; BR112018071756A2; WO2017187874A1; SG11201809190WA; CN109071948A; TWI727035B; TW201807114A; BR112018071756B1; KR102395402B1; JP6928849B2; CN109071948B

Abstract

The curable composition according to the present invention has excellent water repellency and water sliding properties, and good application workability, wear resistance, and storage stability. This curable composition is particularly useful for the formation of a coating on a metal surface, a coated surface, or a resin surface of an automobile body or a train car for the purpose of imparting, to the surface, water repellency, water sliding properties, durability, etc. This curable composition contains: (A) 100 parts by mass of a silicone resin having a viscosity of 50-500 mm

Description

SPECIFICATION

Title of Invention

CURABLE COMPOSITION

Technical Field

[0001]

The present invention relates to a curable composition which essentially contains

a combination of a polyorganosiloxane compound having a viscosity falling within a

specific range, a catalyst consisting of a specific metal compound, and a volatile organic

compound having a boiling point falling within a specific range, at a specific

compositional ratio, and relates to a curable composition which can harden under a

room-temperature environment to form a coating imparting water repellency, water

sliding property and durability to a metal surface, a painted surface or a resin surface,

particularly preferably a painted surface such as an automobile body.

Background Art

[0002]

Solid, semi-solid or liquid curable compositions have conventionally been

applied and laid on a painted steel sheet of an automobile body and the like for the

purpose of protection and aesthetic improvement. As such a curable composition, a

composition obtained by adding a volatile organopolysiloxane oil and a volatile

dimethylpolysiloxane to a moisture-curable organopolysiloxane, an organic solvent and

a curing catalyst (Patent Document 1); and a composition to which a high-viscosity

silicone gum is added (Patent Document 2) are known, for example. However, these

compositions were difficult to exhibit water repellency for a long time, because the non

reactive organopolysiloxane oil volatilized and dissipated over time.

[0003]

In order to solve the above-mentioned problem, various compositions consisting

of a moisture-curable silicone oligomer, an organic solvent, a curing catalyst, and a

silicone oil having a reactive functional group in the molecule have been proposed.

Patent Document 3 discloses a composition using a reactive silicone oil having a

reactive group selected from a carbinol group, a carboxy group, an amino group, a

hydroxyl group (a silanol group) and the like at both terminals of the molecular chain,

and Patent Document 4, Patent Document 5, etc. disclose compositions obtained by

diluting a low-viscosity reactive silicone oligomer having an alkoxysilyl group at the

terminal of the molecular chain in an alcohol-based solvent, a paraffin-based solvent, an

aromatic solvent, an ester-based solvent, a glycol-based solvent, or the like.

Furthermore, Patent Document 6 proposes a composition using a reactive silicone oil

having a carbinol group or an amino group at the side chain of the molecule, and Patent

Document 7 proposes a composition comprising a fluorine-containing alkoxysilane.

Patent Document 8, Patent Document 9, Patent Document 10, Patent Document 11, etc.

disclose compositions obtained by diluting a reactive silicone oligomer having an

alkoxysilyl group at the terminal of the molecular chain with a large amount of solvent

such as isoparaffin-based solvent and kerosene. Patent Document 12 discloses a

composition obtained by diluting a reactive silicone oligomer with a high-boiling point

isoparaffin-based solvent.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1: Japanese Patent Application Laid-Open No. 10-36771

Patent Document 2: Japanese Patent Application Laid-Open No. 2013-194058

Patent Document 3: Japanese Patent Application Laid-Open No. 2008-75021

Patent Document 4: Japanese Patent Application Laid-Open No. 2006-45507

Patent Document 5: Japanese Patent Application Laid-Open No. 2007-161989

Patent Document 6: Japanese Patent Application Laid-Open No. 2010-31074

Patent Document 7: WO 1996/000758, pamphlet

Patent Document 8: Japanese Patent Application Laid-Open No. 2009-138063

Patent Document 9: Japanese Patent Application Laid-Open No. 2009-138062

Patent Document 10: Japanese Patent Application Laid-Open No. 2013-166957

Patent Document 11 Japanese Patent Application Laid-Open No. 2010-202717

Patent Document 12: Japanese Patent Application Laid-Open No. 2012-241093

Summary of Invention

Problem to be solved

[0005]

However, all of these compositions are difficult to simultaneously satisfy

properties such as storage stability in an uncured state, water repellency of a cured film,

water slip property (water sliding property) and wear resistance. Furthermore, wet

wiping or another agent wiping up is required for evenly applying these compositions.

If trying to lay the compositions by only dry-wiping, it cannot be wiped off smoothly,

resulting in an uneven film, and thereby homogenous film formation is difficult. That

is, these compositions have poor workability.

Solution to Problem

[0006]

Thus, it was difficult to satisfy the properties required for the coating and the like

with the conventional coating-forming curable composition. As a result of intensive

studies to improve these properties, the present invention is to use a curable

composition having the following constitution: (A) 100 parts by mass of a silicone resin

having a viscosity of 50-500 mm 2 s-1 at 25°C and having a hydrolysable reactive group,

(B) 1.0-30 parts by mass of an aluminum-based catalyst for condensation reaction, and

(C) 600-1700 parts by mass of an organic solvent which contains 40 mass% or more of a naphthene hydrocarbon compound and of which the boiling point or the temperature range from the initial boiling point to the dry point falls within a range of 140-200°C.

[0007]

Also, the present invention includes the following embodiments. The second

embodiment is the curable composition according to the first embodiment, for which the

boiling point or the temperature range from the initial boiling point to the dry point of

the (C) falls within a range of 142-175°C, and a temperature difference between the

initial boiling point and the dry point (temperature distribution) is within 20°C when the

boiling points are not one temperature.

[0008]

The third embodiment is the curable composition according to the first or second

embodiment which forms a coating on a surface of a steel plate or a painted steel plate.

[0009]

The fourth embodiment is the curable composition according to the third

embodiment for which the steel plate or the painted steel plate is an automobile body.

[0010]

The fifth embodiment is a method for forming a coating by: applying the curable

composition according to any one of the first to fourth embodiments on the surface of

the automobile body; volatilizing the (C) under a normal-temperature or heating

environment; and then dry-wiping, or wet-wiping followed by dry-wiping, the surface.

[0011]

The sixth embodiment is a cured coating formed by the method for forming the

coating according to the fifth embodiment.

Effects of Invention

[0012]

The curable composition according to the present invention is used, so that it

becomes possible to provide a coating, on steel plates or painted steel plates used for automobile bodies and the like, which has a preferable water repellency and water sliding property and is excellent in wear resistance, storage stability, workability in a wiping step, and the like.

Description of Embodiments

[0013]

Hereinafter, the details of the present invention will be explained. Component

(A) contained in the curable composition according to the present invention is a silicone

resin having a viscosity of 50-500 mm2s-I at 25°C and having a hydrolyzable reactive

group in its molecule. The component exerts a main action in expressing functions

such as water repellency, water sliding property and wear resistance in the cured coating

made of the curable composition according to the present invention. Herein, the

silicone resin refers to a compound obtained by subjecting a polyfunctional alkoxysilane

compound to partial hydrolysis and dealcoholization condensation (also referred to as

partial hydrolysis condensation herein) with a known catalyst such as an acid, a base, an

organotin compound or an organotitanium compound, and also refers to a silicone

compound having a hydrolyzable group derived from the alkoxysilane compound at the

molecular chain terminal and/or side chain and the like, and having a linear or three

dimensional network structure. Typically, the compound is a partially hydrolyzed

condensate of an alkoxysilane compound represented by the following structural

formula (1).

[0014]

R I x- Si(OR2 ) 4_x -.- Formula (1) Herein, each of R1 and R2 independently represents an aliphatic, alicyclic or aromatic

hydrocarbon group having 1-8 carbon atoms which may have a substituent, preferably

an aliphatic hydrocarbon group having 1-5 carbon atoms, and particularly preferably a

substituent selected from a methyl group, an ethyl group and a propyl group. In

addition, x represents an integer of 0-3, preferably 0 or 1, particularly preferably 1.

The component (A) can be prepared by: adding a known hydrolysis catalyst to the

compound represented by the above-mentioned structural formula; and stirring the

mixture while heated in the presence of moisture so as to cause the partial hydrolysis

condensation. In the above-mentioned structural formula, when x represents 0 or 1,

the polymer of the compound will have an alkoxy group represented by (OR 2 ) at the

side chain when the polymer is linear, or alternatively the polymer does not have a

linear structure but constitutes a three-dimensional crosslinked body, and partly contains

an alkoxy group in the structure. Although x may be 2 or 3 for the compound, a

compound in which x represents 0 or 1 is preferable for effectively adding an alkoxy

group to the structure of the component (A).

[0015]

In the component (A), a measurement value of a viscosity of the compound 21 alone at 25°C in accordance with JIS-Z-8803 falls within a range of 50-500 mm s-. In

the present invention, the viscosity of the component (A) falls within the above

mentioned range, so that the cured coating of the curable composition can possess good

water repellency, water sliding property or wear resistance, or a plurality of these

properties.

[0016]

As the component (A), any commercial product can be appropriately used as

long as it has the above-mentioned properties. It can be exemplified by X-40-9250

(available from Shin-Etsu Chemical Co., Ltd., a partially hydrolyzed condensate of a

mixture in which both RI and R2 represent methyl groups and x = 1 and 2 in the formula

(1), a viscosity at 25°C is about 160 mm2 1), X-40-9225 (available from Shin-Etsu

Chemical Co., Ltd., a compound in which both RI and R2 represent methyl groups in the

formula (1), a weight-average molecular weight is about 3,600, a viscosity at 25°C is

100 mm2s ), X-40-9246 (available from Shin-Etsu Chemical Co., Ltd., a compound in

which both RI and R2 represent methyl groups in the formula (1), a weight-average molecular weight is about 6,000, a viscosity at 25°C is 80 mm2s-'), XR31-B 2733

(available from Momentive Performance Materials Japan LLC, a partially hydrolyzed

condensate of a mixture in which RI represents a methyl group and a phenyl group, R2

represents a methyl group, and x = 1 and 2 in the formula (1), a viscosity at 25°C is

about 220 mm2s ), SH 550 (available from Dow Corning Toray Co.,Ltd., a partially

hydrolyzed condensate in which RI represents a methyl group and a phenyl group, R2

represents a methyl group, and x = 2 in the formula (1), a viscosity at 25°C is about 135

mm2s-1), and the like, and they may be used alone or in combination.

[0017]

The component (B) contained in the curable composition according to the

present invention is an aluminum-based catalyst for condensation reaction, which is a

compound for condensation reaction by reaction of the hydrolyzable group (Si-OR 2

) contained in component (A) with air moisture and the like. In the present invention, an

aluminum-based compound is used as a catalyst for condensation reaction, so that

degradation of the appearance due to coloring of the cured coating or the like can be

prevented. As the aluminum-based catalysts for condensation reaction, various

organoaluminum compounds are known, which can be exemplified by an aluminum salt

compound such as aluminum octylate, aluminum triacetate and aluminum tristearate; an

aluminum alkoxide compound such as aluminum trimethoxide, aluminum triethoxide,

aluminum triallyloxide and aluminum triphenoxide; an aluminum chelate compound

such as aluminum methoxy bis(ethylacetoacetate), aluminum methoxy

bis(acetylacetonate), aluminum ethoxy bis(ethylacetoacetate), aluminum ethoxy

bis(acetylacetonate), aluminum isopropoxy bis(ethylacetoacetate), aluminum

isopropoxy bis(methyl acetoacetate), aluminum isopropoxy bis(t-butylacetoacetate),

aluminum butoxy bis(ethylacetoacetate), aluminum dimethoxy (ethylacetoacetate),

aluminum dimethoxy (acetylacetonate), aluminum diethoxy (ethylacetoacetate),

aluminum diethoxy (acetylacetonate), aluminum diisopropoxy (ethylacetoacetate), aluminum diisopropoxy (methylacetoacetate), aluminum tris(ethylacetoacetate), aluminum tris(acetylacetonate) and aluminum octylacetoacetate diisopropylate, and the like, and they may be used alone or in combination. Above all, aluminum tris(acetylacetonate), aluminum tris(ethylacetoacetate), aluminum diisopropoxy

(ethylacetoacetate), aluminum octylacetoacetate diisopropylate, aluminum

monoacetylacetonate bis(ethylacetoacetate) are particularly preferable.

[0018]

As the component (B), known commercial products can be used, e.g., DX-9740

(mixture of aluminum alkoxide compounds) and CAT-AC (mixture of aluminum

alkoxide compounds, a diluted product of 50 mass% toluene) available from Shin-Etsu

Chemical Co., Ltd., as well as Alumichelate A (W) (aluminum tris(acetylacetonate)),

Alumichelate D (aluminum monoacetylacetonate bis(ethylacetoacetate), active

ingredient: 76 mass%), AIPD (aluminum isopropylate), ALCH (aluminum diisopropoxy

(ethylacetoacetate)) and ALCH-TR (aluminum tris(ethyl acetoacetate)) available from

Kawaken Fine Chemicals Co.,Ltd., and the like are used, and they may be used alone or

in combination.

[0019]

The composition amount of the component (B) in the present invention falls

within a range of 1.0-30 parts by mass, preferably 1.5-25 parts by mass based on 100

parts by mass of the component (A). If the amount is less than the above-mentioned

composition amount, there is a possibility that the curable composition according to the

present invention cannot form a cured coating having a sufficient strength due to poor

curing, and on the other hand, if the amount exceeds the above-mentioned composition

amount, there is a possibility that the curable composition according to the present

invention has a problem of storage stability at normal temperature.

[0020]

The component (C) contained in the curable composition according to the present invention is an organic solvent which contains 40 mass% or more of a naphthene hydrocarbon compound and of which the boiling point falls within a range of

140-200°C, preferably 141-185°C, particularly preferably 142-175°C, which is an

essential component in a process that the component (A) and the component (B) are

uniformly dissolved and diluted to form a thin film. The naphthene hydrocarbon

compound described in the present invention refers to a saturated hydrocarbon having a

cyclic structure in the molecule, and as long as the compound has this structure, the

cyclic structure may include one or more functional groups such as a halogen group or

various organic groups. From the viewpoints of reactivity, odor, viscosity, etc. of the

composition, it is particularly preferable that the functional group is a hydrocarbon

group having at least about 3 carbon atoms such as a methyl group, an ethyl group, an

n-propyl group and an i-propyl group. When the boiling point of the component (C) is

not lower than the lower limit value of the above-mentioned range, the curable

composition according to the present invention can stay in a liquid state on the substrate

in a period necessary for forming a film. On the other hand, when the boiling point is

not more than the upper limit value of the above-mentioned range, the curable

composition according to the present invention can have appropriate volatility and

obtain preferable workability. Herein, when the boiling points are not one temperature

because of the component being a mixture or the like, the boiling point range in the

present invention refers to a range including the boiling starting temperature (initial

boiling point) and the boiling end temperature (dry point). In this case, from the

viewpoint of workability, it is particularly preferable that the temperature difference

(temperature distribution) between the initial boiling point and the dry point is within

0 C.

[0021]

An organic solvent containing 40 mass% or more of a naphthene hydrocarbon

compound as the component (C) is used, so that the cured product of the component (A) which has been progressively cured on the substrate can be homogenously spread by dry-wiping when forming the cured coating of the curable composition according to the present invention. Although the specific mechanism for expressing such a function is unknown, it is considered that, by using an organic solvent having the above-mentioned constitution, the solvent can act like a plasticizer in the cured product which has been progressively cured on the substrate to soften the cured product to some extent, enabling to stretch the cured product by the external force of dry-wiping, so that the cured product can be formed into a thin film on the substrate.

[0022]

In the present invention, as a naphthene hydrocarbon compound contained in the

organic solvent, any material can be appropriately selected. Herein, when the organic

solvent is a material consisting only of a naphthene hydrocarbon compound, the solvent

can be exemplified by propylcyclohexane (boiling point: 155°C), 1,3,5

trimethylcyclohexane (boiling point: 140°C), 1,2,3-trimethylcyclohexane (boiling point:

151C), 1,2,4-trimethylcyclohexane (boiling point: 145°C), cyclooctane (boiling point:

149°C), 1,1,3,5-tetramethylcyclohexane (boiling point: 148°C), cyclooctane (boiling

point: 149°C), and the like. Each of these naphthene hydrocarbon compounds may be

used alone or as a mixture of plural kinds. If the temperature range from the boiling

point, i.e., initial boiling point, to the dry point of the mixture is included within the

above-mentioned temperature range, the mixture may contain a naphthene hydrocarbon

compound in which the boiling point of the compound alone falls outside the above

mentioned range. Additionally, in the present invention, if the boiling point of the

whole organic solvent is within the above-mentioned range, the organic solvent may

contain an organic solvent compound other than the naphthene hydrocarbon compound.

In this case, a ratio of the naphthene hydrocarbon compound to the whole organic

solvent is 30 mass% or more.

[0023]

As a commercial product of the organic solvent, a product sold as a mixture of

various naphthene hydrocarbon compounds can be used, and exemplified by Swaclean

150 (initial boiling point: 145°C, dry point: 170°C) and Naphtesol 160 (initial boiling

point: 157°C, dry point: 179°C) available from Maruzen Petrochemical CO,LTD.,

Exxsol D 30 (initial boiling point: 145°C, dry point: 163°C) and Exxsol D40 (initial

boiling point: 166°C, dry point: 191°C) available from Exxon Mobil Corporation, and

the like.

[0024]

The composition amount of the component (C) in the present invention falls

within a range of 600-1700 parts by mass, preferably 700-1600 parts by mass based on

100 parts by mass of the component (A). When the composition amount falls within

this range, the curable composition according to the present invention can acquire both

adequate volatility and coating formability, and can be laid with a good workability so

as to achieve homogenous coating formation.

[0025]

Furthermore, in the curable composition according to the present invention, any

additives can be appropriately added unless the properties are damaged. Components

corresponding to a purpose, e.g., an adhesion imparting agent such as reactive or non

reactive silicone oil, alkoxysilane compound and silane coupling agent, an antioxidant,

a corrosion inhibitor, a colorant, a surfactant, a rheology modifier, an ultraviolet

absorber, an infrared absorber, a fluorescence agent, an abrasive, a perfume, a filler and

the like can be selected.

[0026]

The curable composition according to the present invention can be applied to

substrates such as various metals, glass, ceramics and resin, preferably to a metal steel

plate, a painted metal steel plate or a glass surface, particularly preferably to a painted

steel plate used for automobile exterior (also referred to as an automobile exterior steel plate in this specification).

[0027]

Also, the present invention relates to a method for forming a coating using the

curable composition. The method for forming a coating according to the present

invention comprises: applying the curable composition on the surface of the automobile

body; volatilizing the (C) under a normal-temperature or heating environment; and then

dry-wiping, or wet-wiping followed by dry-wiping, the surface. Although the latter

applying method, i.e., the dry-wiping after the wet-wiping may be adopted, the present

invention is characterized in that a cured coating having good properties can be obtained

from the curable composition according to the present invention even by only dry

wiping, and thereby the workability during applying is excellent.

[0028]

The application means in forming the coating of the curable composition is not

particularly limited, and any application means, e.g., manual application using a fiber

impregnated with the composition, brush application, mechanical application using an

automatic machine, and the like can be appropriately selected. In the present invention,

application in accordance with the following method is particularly preferable. That is,

the method comprises: impregnating a fiber such as a dry sponge or waste cloth with a

suitable amount of the curable composition according to the present invention; thinly

spreading the curable composition onto the surface of the substrate by hand; and

volatilizing volatile components by natural drying or forced drying using a dryer or the

like. At this time, the component (A) which is the reactive component contained in the

composition contacts the moisture in the air to advance the hydrolysis reaction by the

action of the catalyst (B), and is cross-linked and cured on the substrate in parallel with

volatilization of the volatile component to form a resinous cured product. Thereafter,

the cured product can be spread out by dry-wiping with a dry cloth or the like to form a

coating layer with a homogeneous cured coating. For the conventionally known curable composition, wet-wiping after volatilization of the volatile components, or a post-process in which the surface is treated with a treatment liquid for another wiping up, and then dry-wiped with a dry cloth, have been required during the applying. On the other hand, although the curable composition according to the present invention may be subjected to these post-processes, a homogeneous cured coating can be obtained even by only dry-wiping with the dry cloth after volatilization of the solvent, which is extremely excellent in workability. Herein, the cured coating made of the curable composition according to the present invention is preferably a thin film, and preferably has a film thickness of approximately 0.002-75 [m, preferably 0.01-50 [m, more preferably 0.05-10 [m. When the film thickness of the cured coating falls within the above-mentioned range, good water repellency, water sliding property, workability during applying and wear resistance can be concurrently achieved.

[0029]

Hereinafter, the effects of the present invention will be explained in detail with

reference to Examples, but these Examples are not intended to limit the embodiments of

the present invention.

Examples

[0030]

The properties of the curable composition according to the present invention

were evaluated in the following Examples and Comparative Examples. Herein, in

relation to the respective properties, a composition of which not more than one property

was rated as "Medium (triangle A)" is preferable, and a composition of which all

properties were rated as "Good (circle 0)" is more preferable, as the composition to be

used for the purpose of coating formation. In addition, each curable composition

(hereinafter, also referred to simply as "composition") evaluated in Examples and

Comparative Examples according to the present invention was prepared by mixing raw

materials shown in Tables 1 and 2 with a mass ratio described in the same tables, and stirring at 25°C for 30 minutes.

[0031]

[Method for evaluating water repellency/water sliding property]

About 2 ml of each composition shown in the tables was infiltrated into tissue

paper, thinly applied on a black painted plate (available from ASAHI-BETECHNO

K.K., material: SPCC-SD, standard: JIS-G-3141, size: 0.8 mmx70 mmx150 mm, one

surface was painted black with aminoalkyd after chemical conversion and

electrodeposition) by hand, allowed to stand in a room at 25°C for 10 minutes, and then

a remainder was wiped off with a dry microfiber cloth. This was further allowed to

stand in a room at 25°C for 2 weeks for curing, to obtain a test piece coated with each

composition. One drop (about 0.05 ml) of purified water was dropped to this test piece,

and a contact angle with the water drop (water contact angle) was measured using a

contact angle meter (DM-500, available from Kyowa Interface Science Co., Ltd.) to

evaluate the water repellency. The water repellency was evaluated in accordance with

an evaluation criterion, where a test piece having a water contact angle of larger than

950 was rated as "Good (0)", a test piece having a water contact angle of 83-95° was

rated as "Medium (A )", and a test piece having a water contact angle of smaller than

83° was rated as "Bad (cross X)". In addition, one drop (about 0.05 ml) of purified

water was dropped to the same test piece, the test piece was gradually inclined from a

horizontal state, and an angle at which the water droplet started to flow (water sliding

angle) was visually observed to evaluate the water sliding property. The water sliding

property was evaluated in accordance with an evaluation criterion, where a test piece

having a water sliding angle of smaller than 35° was rated as "Good (0)", a test piece

having a water sliding angle of 35-45° was rated as "Medium ( A )", and a test piece

having a water sliding angle of larger than 45° was rated as "Bad (X )".

[0032]

[Method for evaluating wear resistance]

A test piece on which the composition was applied was prepared by the same

method as used for evaluating the water repellency/water sliding property. The surface

on a side of the test piece on which the composition was applied was subjected to a

wear resistance test using a simple friction tester (available from Imoto Machinery Co.,

Ltd.). In the test, a moving plate on which the test piece was fixed was reciprocated

with one round-trip of 100 mm at a rate of 30 times a minute, and on the center of the

test piece, a frictional object loaded with a 300 g weight was placed, which object was

reciprocated 300 times to abrade the test piece. A water contact angle of the surface

after wear was measured in the same manner as described above to evaluate the wear

resistance. Evaluation was carried out in accordance with an evaluation criterion,

where a test piece of which a water contact angle after 300 reciprocations was larger

than 90% of the water contact angle before wear was rated as "Good (0)", a test piece

of 7 5 - 9 0 % was rated as "Medium ( A)", and a test piece of smaller than 75% was rated

as"Bad(X)". Herein, the frictional object used in the test was prepared by wrapping

a dried clean fabric having a width of 40 mm impregnated with an adequate amount of

distilled water (water-absorbable cloth made of cellulose/cotton composite fiber,

"Threebond 6644E" available from ThreeBond Co., Ltd.) around a stainless steel

cylinder having a diameter of 20 mm, and placed so that the axis of the cylinder was

oriented in a direction orthogonal to the moving direction of the moving plate.

[0033]

[Method for evaluating workability]

The composition was applied on the coated plate under the same conditions as in

the evaluation of the water repellency and water sliding property, which was allowed to

stand in a room at 25°C for 10 minutes, then the remainder was dry-wiped with a dry

microfiber cloth, and the workability was evaluated by a sensory test on the resistance

during wiping. Evaluation was carried out in accordance with an evaluation criterion,

where a test piece which could be wiped evenly with light force was rated as "Good

(O)", and a test piece on which jaggedness was felt during wiping was rated as "Bad

(X)".

[0034]

[Method for evaluating storage stability]

About 50 g of each composition shown in the tables was put into a 100 ml

colorless transparent glass bottle, sealed, stored in a thermostat bath set to 40°C for 1

month, and then an appearance of the liquid was visually observed to evaluate the

storage stability. Evaluation was carried out in accordance with an evaluation criterion,

where a test piece showing no discoloration was rated as "Good (0)", a test piece

showing slight yellowing or browning was rated as "Medium ( A)", and a test piece

showing apparent discoloration was rated as "Bad (X)".

[0035]

The following materials were used as raw materials contained in each

composition of Examples and Comparative Examples.

(A) Silicone resins having a viscosity of 50-500 mm 2 s-I at 25°C and having a

hydrolysable reactive group, and a comparative component therefor: -X-40-9250: a compound available from Shin-Etsu Chemical Co., Ltd., in which

both R1 and R2 represent methyl groups in the formula (1), a weight-average molecular

weight is about 2,100 and a viscosity at 25°C is 160 mm2s-I; -X-40-9225: a compound available from Shin-Etsu Chemical Co., Ltd., in which

weight is about 3,600 and a viscosity at 25°C is 100 mm2s-I; -X-40-9246: a compound available from Shin-Etsu Chemical Co., Ltd., in which

weight is about 6,000 and a viscosity at 25°C is 80 mm2s-I; - (Comparative product) KR-500: a compound available from Shin-Etsu

Chemical Co., Ltd., in which both RI and R2 represent methyl groups in the formula (1), a weight-average molecular weight is about 1,000 and a viscosity at 25°C is 25 mm s

(B) An aluminum-based catalyst for condensation reaction, and comparative

components therefor:

- DX 9740: an aluminum alkoxide compound available from Shin-Etsu Chemical

Co., Ltd.;

- (Comparative product) D25: an organotitanium-based catalyst available from

Shin-Etsu Chemical Co., Ltd.;

- (Comparative product) ORGATIX TC401: a 2-propanol solution containing 65

mass% of titanium tetraacetylacetonate, available from Matsumoto Fine Chemical

Co.Ltd..

(C) Organic solvents having a boiling point within a range of 140-200°C and

containing a naphthene hydrocarbon compound, and comparative components therefor:

- Swaclean 150: an organic solvent comprising a mixture of a C 9

alkylcyclohexane, available from Maruzen Petrochemical CO., LTD., the initial boiling

point is 145°C and the dry point is 170°C;

- Exxsol D30: an organic solvent containing about 50% of a dearomatized

naphthene hydrocarbon compound, available from Exxon Mobil Corporation, the initial

boiling point is 145°C and the dry point is 163°C;

- Exxsol D40: an organic solvent containing about 90% of a dearomatized

boiling point is 166°C and the dry point is 191°C;

- (Comparative product) Exxsol D80: an organic solvent comprising a

hydrogenated light naphtha hydrocarbon compound, available from Exxon Mobil

Corporation, the initial boiling point is 205°C and the dry point is 240°C;

- (Comparative product) KYOWASOL C-900: an organic solvent comprising a

mixture of a C 9 alkane isomer, available from KH Neochem Co., Ltd., the initial boiling

point is 131°C and the dry point is 141°C.

[0036]

o

0 0 0i 0 0

0 0 00 0

o o'- a

OOON 18 o o

0 0 00 0000

C

- o0e

[0037]

- 0 0 0 Cl x 0 0 2 0

0 0

X X 00 2 0

o ~ 0 0

X ~1 >6 >6 2C -~

0

0 0

0 0 < Q < 2 C 0

0 C-I N 0 0 0 0 2 C 0

0 C-

0 0 0 0>60 2C 0

0

C. Cl x 0 0 x 2C 0

0 0 Cl - 0

0 0 00>6 2C 0

0 ~ ~C C- 0 C- C--I 0 ~ a~ ~ ~ ~ - ~ ~

C) C- ~-~<-~%--~ ~ C. 0 0 ~ C

[0038]

In Examples of Table 1, it could be confirmed that all of the compositions

according to the present invention containing respective constituents (A) to (C) at a

predetermined compositional ratio were excellent in water repellency, water sliding

property, wear resistance, workability and storage stability. In Example 7, since the

volatilization of (C) during applying was somewhat retarded because of using a material

having a slightly higher boiling point range as (C), it was considered that a somewhat

larger quantity of composition was wiped off and removed during wiping, thus the

thickness of the coating was decreased, and as a result, the wear resistance was slightly

poor. On the other hand, according to Comparative Examples of Table 2, it was

confirmed that Comparative Examples 1, 4 and 5 using materials as (B) other than the

materials according to the present invention, for example, had the insufficient storage

stability. Comparative Example 2 using materials as (B) and (C) other than the

materials according to the present invention is poor at not only the storage stability but

also the water repellency and the water sliding property. Comparative Example 3

using a material as (C) having a boiling point out of the range according to the present

invention has the unpreferable workability. Comparative Example 6 using materials as

(A) and (B) other than the materials according to the present invention were not good at

all of the properties. For Comparative Examples 7 and 8 in which the composition

of (A), (B) and (C) was at a mass ratio out of the specific range according to the present

invention, it was confirmed that a sufficient film thickness could not be formed because

of low concentration of the composition, both Comparative Examples showed poor

wear resistance, and properties such as water repellency and water sliding property were

also insufficient. As described above, it was confirmed that, unless the composition

contained all the predetermined constituents according to the present invention, any one

or more of the above-mentioned properties were insufficient so that the composition

was not suitable for the coating formation application.

Industrial Applicability

[0039]

In the curable composition according to the present invention, the cured coating

comprises excellent water repellency, water sliding property and wear resistance, as

well as excellent workability and storage stability. Consequently, the composition is

useful for forming a thin coating layer for imparting a protective performance such as

water repellency, water sliding property and durability to a metal surface, a painted

surface, a resin surface or the like of an automobile body and a train carriage.

[0040]

By way of clarification and for avoidance of doubt, as used herein and except

where the context requires otherwise, the term "comprise" and variations of the term,

such as "comprising", "comprises" and "comprised", are not intended to exclude further

additions, components, integers or steps.

[0041]

Reference to any prior art in the specification is not an acknowledgement or

suggestion that this prior art forms part of the common general knowledge in any

jurisdiction or that this prior art could reasonably be expected to be combined with any

other piece of prior art by a skilled person in the art.

Claims

1. A curable composition comprising:

(A) 100 parts by mass of a silicone resin having a viscosity of 50-500 mm 2 s-1 at

°C and having a hydrolysable reactive group;

(B) 1.0-30 parts by mass of an aluminum-based catalyst for condensation

reaction; and

(C) 600-1700 parts by mass of an organic solvent which contains 40 mass% or

more of a naphthene hydrocarbon compound and of which a boiling point (a

temperature range from an initial boiling point to a dry point when the boiling point is

not one temperature) falls within a range of 140-200°C.

2. The curable composition according to claim 1, wherein the boiling point of the

(C) falls within a range of 142-175°C, and a temperature difference between the initial

boiling point and the dry point is within 20°C.

3. The curable composition according to claim 1 or 2, wherein the curable

composition forms a coating on a surface of a steel plate or a painted steel plate.

4. The curable composition according to claim 1 or 2, wherein the curable

composition forms a coating on a surface of an automobile body.

5. A method for forming a coating by: applying the curable composition according

to any one of claims 1-4 on a surface of an automobile body; volatilizing the (C) under a

normal-temperature or heating environment; and then dry-wiping, or wet-wiping

followed by dry-wiping, the surface.

6. A cured coating formed by the method for forming the coating according to

claim 5.