JPH02286772A - Coating composition - Google Patents

Abstract

PURPOSE:To prepare a coating compsn. which can be cured with water and humidity and which forms a coating film excellent in the surface properties by reacting a silane coupling agent contg. a reactive org. functional group with an org. polyisocyanate and incorporating a specific modified fluororesin into the resulting reaction product as a film-forming component. CONSTITUTION:A silane coupling agent contg. a reactive org. functional group (e.g. a compd. of formula I or formula II) is reacted with an org. polyisocyanate (e.g. toluene 2,4-diisocyanate); into the resulting reaction product, a fluororesin (e.g. fluoroolefin-vinyl ether copolymer resin) modified with a modifier having at least one free NCO group is incorporated as a film-forming component, thus giving a coating compsn. The resulting compsn., being a curable one- component coating compsn., gives a coating film with excellent properties inherent to the fluororesin while exhibiting a high solubility in a solvent generally used for coating.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a coating composition, and more particularly to a coating composition that is curable with water and/or moisture and forms a coating film with excellent surface properties. The present invention relates to a fluorine-containing resin coating composition.

(Prior art and its problems) Conventionally, paints have been applied to the surfaces of various structures, buildings, articles, etc., to prevent corrosion and deterioration of the objects to be coated, and to protect these structures and articles. It is widely used to give a good appearance.

Various types of paints are known as such protective and bran-collecting paints, but in recent years, fluorine-containing resin paints have been widely used as paints with excellent weather resistance, antifouling properties, and other types of durability. It looks like this.

However, although fluorine-containing resins inherently have excellent weather resistance, heat resistance, water repellency, chemical resistance, electrical properties, etc., they are not soluble in boat paint solvents (therefore, they are only suitable for very special applications). has been used.

In order to solve these drawbacks, recently, fluorine-containing polymers that are soluble in common paint solvents have been developed by copolymerizing fluorine-containing monomers with common monomers, and some of them are used for paints. However, as a result of these resins having a general non-fluorine-containing monomer moiety, it is inevitable that the excellent properties of fluorine-containing resins, such as stain resistance, abrasion resistance, non-adhesiveness, and lubricity, will deteriorate. Ta.

In addition, since the above-mentioned fluorine-containing resin paints have various reactive functional groups introduced into them, by using a curing agent, in other words, as a two-component type, even higher degrees of durability can be imparted. In most cases, the hardening agents used are
Since it is a melamine or isocyanate, in the case of heat curing,
A heating device is required, which poses problems such as a fire hazard and poor curing.Furthermore, in the case of room temperature curing, there are still problems such as pot life.

Therefore, the object of the present invention is to provide a copolymer of a fluorine-containing monomer and a non-fluorine-containing monomer, which has good solubility in general paint solvents, yet has various excellent properties inherent to fluorine-containing resins. It is an object of the present invention to provide a coating composition which can be cured in one liquid.

(Means for solving problems) The above objects are achieved by the present invention as described below.

That is, the present invention provides a reaction product of a silane coupling agent having a reactive organic functional group and an organic polyisocyanate, which is a fluorine-containing resin modified with a modifier having at least one free incyanate group. This is a coating composition characterized by containing as a film-forming component.

(Function) A film-forming fluororesin is modified with a modifier that is a reaction product of a silane coupling agent having a reactive organic functional group and an organic polyisocyanate and has at least one free isocyanate group. By doing so, it is possible to provide a coating composition that has good solubility in general coating solvents, provides a coating that has various excellent properties inherent to fluorine-containing resins, and is liquid-curable. I can do it.

(Preferred Embodiments) Next, the present invention will be described in more detail by citing preferred embodiments.

The modifier used in the present invention and which mainly characterizes the present invention is a reaction product of a silane coupling agent having a reactive organic functional group and an organic polyisocyanate, and has at least one free isocyanate group. are doing.

The silane coupling agent having a reactive organic functional group used in the present invention is a compound having one or more alkoxysilyl groups and various reactive groups, and these reactive groups include amino groups, epoxy groups, etc. group, hydroxyl group, thioalcohol group, carboxyl group, vinyl group, etc.
Particularly preferred reactive groups are amino, hydroxyl and thioalcohol groups.

The above-mentioned coupling agent is represented by the following formulas (I) and (n), for example.

alkyl group, A is hydrogen atom, aminoethyl group, glycidyl group, (meth)acryloyl group, B is allyl group, trialkoxysilylpropyl group, dialkoxyalkylsilylpropyl group, glycidyl group, etc., m+n=3, n
= represents 2 or 3.

Some preferred specific examples are as follows.

H2N (CH2+ JH(CH21sSi (OCH
312(CH,lH2N (CHzl JH(CHzl
@sL (oczusl t (CH-1H2N F
CH212NHfcH2) isl (OCHsl 3
H2N (CH2+ 2NH((:H2) 3Si (
OC2H,131(J CH□3st (ocH3)3
H2N fcn2) 3S1 (OGJsl 3 In the above formula, X is a reactive group as described above or an alkyl group having the reactive group, R is a hydrogen atom, a lower alkyl group or a lower alkoxy group, and Ro is a lower 0◇CHzCH2Si (Q.C.
:H@l sH3(CH213Si (OCH313H
3(CH213Sl (oc, u513H2N (cH
212NHCH2-Ph-CH2C,H,Si ((:
H,).

The above-mentioned silane coupling agents are examples of silane coupling agents preferable in the present invention, and the present invention is not limited to these examples. are currently commercially available and can be easily obtained from the market, and any of them can be used in the present invention.

As the organic polyisocyanate to be reacted with the above-mentioned silane coupling agent, any conventionally known organic polyisocyanate can be used, but preferred examples include toluene-2,4-diisocyanate and 4-methoxy-diisocyanate.
1,3-phenylene diisocyanate, 4-isopropyl-1,3-phenylene diisocyanate, 4-chloro-1,3-phenylene diisocyanate, 4-butoxy-1,3-phenylene diisocyanate, 2,4-diisocyanate-diphenyl ether, Methylene diisocyanate-1., 4.4-methylenebis(phenylisocyanate), shrylene diisocyanate, 1.5-naphthalene diisocyanate, benzidine diisocyanate, 0-nitrobenzidine diisocyanate, 4.4-dibenzyl diisocyanate, 1.4 -tetramethylene diisocyanate, 1.6-tetramethylene diisocyanate, 1.10-decamethylene diisocyanate, 1.4
-Cyclohexylene diisocyanate, xylylene diisocyanate, 4,4-methylenebis(cyclohexyl isocyanate), 1,5-tetrahydronaphthalene diisocyanate, and the like.

Further examples include adducts of these organic polyisocyanates and other compounds, such as those having the following structural formulas, but are not limited thereto.

OCH3ゝ. 6 Alternatively, urethane prepolymers obtained by reacting these organic polyisocyanates with low molecular weight polyols or polyamines to form terminal isocyanates can also be used. Particularly preferred are non-yellowing polyisocyanes 1 to 1.

The modifier used in the present invention combines a silane coupling agent having a reactive organic functional group as described above and an organic polyisocyanate as described above, such that the organic functional group and incyanate group are present in one molecule. at a functional group ratio such that there is an excess of one or more incyanate groups, preferably one to two, in the presence or absence of an organic solvent and a catalyst, from about 0 to 150°C.
, preferably by reacting at a temperature of 20 to 80°C for about 10 minutes to 3 hours.

The modifier may be prepared in a solvent or without a solvent, but in terms of process, by preparing it in an organic solvent, the resulting solution can be used as it is for modifying the fluororesin. Therefore, it is advantageous.

Any organic solvent that may be used in the production of such a modifier may be used as long as it is inert to the respective reaction raw materials and products.

Preferred organic solvents include methyl ethyl ketone, methyl-n-propyl ketone, methyl isobutyl ketone, diethyl ketone, methyl formate, ethyl formate,
Propyl formate, methyl acetate, ethyl acetate, butyl acetate, etc. Also, acetone, cyclohexane, tetrahydrofuran, dioxane, methanol, ethanol, isopropyl alcohol, butanol, toluene, xylene,
Dimethylformamide, dimethyl sulfoxide, perchlorethylene, trichlorethylene, methyl cellosolve, butyl cellosolve, cellosolve acetate, etc. can also be used.

The fluorine-containing resin used as the film-forming resin in the present invention and modified with the above-mentioned modifier has a group that reacts with an isyanate group and is soluble in a solvent. are commercially available, and any of these commercially available fluorine-containing resins can be used in the present invention.

An example of a suitable fluorine-containing resin is a fluorine-containing olefin monomer such as tetrafluoroethylene or trifluorochloroethylene, and a hydroxyl group, a carboxyl group, an amino group,
It is a copolymer with a monomer having a functional group reactive with isocyanate groups, such as an acid anhydride group, an epoxy group, or a thioalcohol group, or it may be one in which these reactive groups are added after copolymerization. . Typical examples of these copolymerizable monomers include vinyl acetate, vinyl ester, (meth)acrylic acid, and various esters thereof. Of course, during copolymerization, a third monomer having no reactive group may be copolymerized. The copolymerization ratio of the fluorine-containing monomer and other monomers is such that the resulting copolymer is soluble in common paint solvents; for example, the molar ratio of the fluorine-containing monomer in the copolymer is 30 A range of 90% to 90% is preferable.

The paint solvent used in the present invention is a solvent commonly used in paints, and includes, for example, the solvents exemplified above.

The coating composition of the present invention has the above-mentioned components as essential components, and their blending ratio is such that the total solid content of the solvent is 5 to 50% by weight, and the film-forming fluorine-containing resin is 10% by weight of the coating material.
It is in the range of about 5 to 30% by weight in 0 parts by weight,
The modifier is used in an amount of 1 to 10 parts per 100 parts by weight of the fluororesin.
A range of 0 parts by weight is preferred. The reaction between the modifier and the fluorine-containing resin may be carried out before or after the preparation of the coating material, and is not particularly limited.

Furthermore, the coating composition of the present invention, like other single boat fishing coatings,
Extender pigments, organic pigments, inorganic pigments, other film-forming resins,
Plasticizers, ultraviolet absorbers, antistatic agents, leveling agents, curing agents, catalysts, etc. can be included as necessary.

Other general film-forming resins that may be used in combination include, for example, various conventionally known film-forming resins, and any of these may be used, such as vinyl chloride resins, vinylidene chloride resins, chloride resins, etc. Vinyl/vinyl acetate/vinyl alcohol copolymer resin, alkyd resin, epoxy resin, acrylonitrile-butadiene resin, polyurethane resin, polyurea resin, nitrocellulose resin, polybutyral resin, polyester resin, melamine resin Examples include resins, urea resins, acrylic resins, polyamide resins, etc., and particularly resins having reactive groups capable of reacting with isocyanate groups in their structures are preferably used. These resins can be used alone or as a mixture, and can be used as a solution or dispersion in an organic solvent.

When the coating composition of the present invention as described above is brought into contact with moisture in the air, water, or steam after coating film formation, the alkoxy group of the alkoxysilyl group reacts with water and the alcohol is eliminated, resulting in crosslinking. and harden. This crosslinking is sufficiently carried out even at room temperature, and therefore, room temperature curing is possible.

In addition, in order to promote the condensation of alkoxysilyl groups, for example, metal salts of carboxylic acids such as alkyl titanates, tin octylate, dibutyltin dilaurate, amine salts such as dibutylamine-2-ethylhexoate, etc. and other common catalysts such as acidic catalysts and basic catalysts.
It is preferably added in an amount of 0,001 to 5% by weight.

The method for producing the coating composition of the present invention itself may be the same as the conventional technique and is not particularly limited.

(Effects) The coating composition of the present invention as described above is easily cured by contacting with moisture in the air, water or steam after forming a coating film, and can be applied to metal structures, such as steel plates, aluminum plates, aluminum sash, etc. Inorganic structures such as glass, cement, and concrete, wood, FRP, polyethylene, polypropylene,
Useful for protection and bran coating of plastic structures such as nylon, polyester, vinyl chloride resin, ethylene vinyl acetate resin, acrylic resin, etc., and has surface hardness, gloss, solvent resistance, stain resistance, light resistance, and non-adhesion. It is possible to provide a coating film with excellent properties.

(Example) Next, the present invention will be explained in more detail by giving examples and comparative examples. It should be noted that unless otherwise specified, the terms in the text or % are based on weight.

Reference Example 1 (Manufacture of modifier) Adduct of hexamethylene diisocyanate and water (Duranate 24A-100, manufactured by Fukaisei Co., Ltd., NCO% = 23.
5) While stirring well at room temperature, add 3-
Gradually drop 124 parts of aminopropyltriethoxysilane and react to form a colorless, transparent and viscous liquid modifier (1) 2
74 parts were obtained.

According to the infrared absorption spectrum of the above modifier, 2.270
Absorption due to free incyanate groups was observed at cm-', and an absorption band based on 5i-0- groups was observed at 1,090 cm-'. Furthermore, when the amount of free incyanate groups in this modifier was quantified, the theoretical value was 4.20%, but the actual value was 3.92%.

Reference Example 2 (Production of Modifier) Adduct of 1 mol of trimethylolpropane and 3 mol of hexamethylene diisocyanate (Coronate HL, manufactured by Nippon Polyurethane, NCO% = 12.5, solid content 75%)
While stirring well at room temperature, 76 parts of N-phenyl-γ-aminopropyltrimethoxysilane was gradually added dropwise to 150 parts of the mixture to react, resulting in 185 parts of the colorless and transparent viscous liquid modifier (II). Obtained.

According to the infrared absorption spectrum of the above modifier, 2.270
Absorption by free isocyanate groups was observed, and
It showed an absorption band based on the -3i-0- group at 1,090 cm-'. Furthermore, when the amount of free incyanate groups in this modifier was quantified, the actual value was 2.82%, while the theoretical value was 3.12%.

Reference Example 3 (Manufacture of modifier) 150 parts of hexamethylene diisocyanate trimer (Coronate EH1 manufactured by Asahi Kasei, NCO% = 21.3) was stirred well at room temperature, and 99% of γ-mercaptopropyltrimethoxysilane was added thereto. Gradually drop the solution to react.
249 parts of a colorless and transparent viscous liquid modifier (III) was obtained.

According to the infrared absorption spectrum of the above modifier, 2.270
Absorption by free isocyanate groups was observed, and
It showed an absorption band based on the -3i-0- group at 1,090 cm-'. Furthermore, when the amount of free incyanate groups in this modifier was quantified, the theoretical value was 4.0%, but the actual value was 3.72%.

Reference Example 4 (Modification of resin) Fluoroolefin-vinyl ether copolymer resin solution (
18 parts of the modifier (I) were added to 300 parts of the resin (solid content 50%, hydroxyl value 24 mgKOH/g, manufactured by Asahi Glass) and reacted at 80°C for 6 hours to obtain a fluorine-containing resin solution modified with the modifier. No incyanate group was observed in this modified resin by infrared absorption spectrum. This is presumed to be due to craft bonding of the modifier to the resin.

Reference example 5 (modification of resin) Fluoroolefin-vinyl ether copolymer resin solution (
20 parts of a modifier (n) was added to 300 parts of a resin (solid content 60%, hydroxyl value 32 mgKOH/g, manufactured by Asahi Glass) and reacted at 80°C for 6 hours to obtain a fluorine-containing resin solution modified with the modifier. No isocyanate groups were observed in this modified resin by infrared absorption spectrum. This is presumed to be due to graft bonding of the modifier to the resin.

Reference Example 6 (Modification of resin) Trifluorochloroethylene copolymer resin solution (solid content 50%, hydroxyl value 25 mgKOH/g, manufactured by Central Glass) 3
20 parts of a modifier (Irl) was added to 00 parts and reacted at 80°C for 6 hours to obtain a fluorine-containing resin solution modified with the modifier. No isocyanate groups were observed in this modified resin by infrared absorption spectrum. This is presumed to be due to graft bonding of the modifier to the resin.

Examples 1 to 3 and Comparative Examples 1 to 3 The modified resin solutions of Reference Examples 4 to 6 were made into paints according to the formulations shown in Table 1 below based on a conventional paint-making method, and coated on a zinc steel plate (treated with phosphoric acid) to a dry thickness of 254 tons. Apply at a ratio of m and leave at room temperature (2
Each film was formed by drying at 3° C. and 36% RH for 10 days, and the physical properties of each film were measured, and the results shown in Table 2 below were obtained.

In Comparative Examples 1 to 3, incyanate was added as a curing agent to the fluorine-containing resin solution used in Reference Examples 4 to 6 before modification to form a coating.

(Left below) (Paint composition) Catalyst: (manufactured) Dibutyltin dilaurate (adjusted to the same final amount considering the amount added during production of the modifier) (Coating film physical properties) Resin*I: Modification Resin (solid content 50%) Resin 92:
Unmodified resin (solid content 50%) titanium oxide: CR-
90 Hardening agent: Coronate EH (Japan Polyurethane ○= and (slightly leaves marks × = completely leaves no marks) Surface quality: Water repellency criteria: 0 = Good repellency ○ = Relatively well repelled Falling angle (°) : The angle at which water droplets start to slide when the coating material is tilted (using a contact angle meter from Kyowa Interface Materials ■) Gloss 2 60° Gloss Adhesion: Gobang adhesion Sellotape Peeling Stain resistance: Lipstick, crayon: Dry Wipe with cloth magic: Black and red were used.

*1 = Wipe off with a dry cloth *2 = Petroleum benzene/ethanol (weight ratio applicant: Dainichiseika Industries Co., Ltd. (and 1 other person) 1/1) Wipe off with a mixed solvent Judgment standard 20 = No trace left at all.

Claims (2)

[Claims] (1) A film-forming component is a fluorine-containing resin that is a reaction product of a silane coupling agent having a reactive organic functional group and an organic polyisocyanate and has been modified with a modifier having at least one free isocyanate group. A coating composition characterized by containing: (2) The coating composition according to claim 1, further comprising water as a curing agent.