JPH04216882A - Coating composition - Google Patents

Abstract

PURPOSE:To provide a new coating composition which gives a film free from deterioration of various excellent functions inherent in fluororesin and is adaptable to one-pack curing. CONSTITUTION:A coating composition which contains as the film-forming component a fluororesin modified with a silane coupling agent having at least one free isocyanate group and with a modifier which comprises a reaction product of a polysiloxane compound having reactive organic functional groups with an organic polyisocyanate and has at least one free isocyanato group.

Description

Description: [0001] 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 coating compositions, especially fluorine-containing resin coating compositions. [0002] Conventionally, paints have been used to form coating films on the surfaces of various structures, buildings, articles, etc., to prevent and protect the objects to be painted from corrosion and deterioration, and to protect these objects from corrosion and deterioration. It is widely used for the purpose of providing excellent cosmetics and surface functions. Various types of paints are known as such protective and cosmetic paints, but in recent years, fluorine-containing resin paints have been widely used as paints with excellent durability, such as weather resistance and stain resistance. It looks like this. [Problems to be Solved by the Invention] However, although fluorine-containing resins inherently have excellent weather resistance, heat resistance, water repellency, chemical resistance, electrical properties, etc., they are not soluble in common paint solvents. Therefore, there is a problem that it can only be used for very special purposes. In order to solve these drawbacks, recently, fluorine-containing polymers have been developed in which fluorine-containing monomers are copolymerized with general non-fluorine-containing monomers to make them soluble in common paint solvents. However, as a result of these copolymerizable resins having non-fluorine-containing monomer moieties, the coating film may lose the excellent properties inherent to fluorine-containing resins, such as stain resistance, abrasion resistance, non-adhesion, and lubricity. There is a problem that cannot be avoided. Furthermore, since the fluorine-containing resin has various reactive functional groups introduced therein, if a curing agent is used to make it a two-component type, even higher degrees of durability can be imparted to the resin. However, most of the curing agents currently in use are melamine or isocyanate, which requires a heating device when curing by heating, which poses problems such as a fire hazard and poor curing. Furthermore, even in the case of room temperature curing, there are problems such as pot life. Therefore, the object of the present invention is to provide a coating composition consisting of a copolymer of a fluorine-containing monomer and a non-fluorine-containing monomer, which has good solubility in general coating solvents, but which has the inherent properties of a fluorine-containing resin. It is an object of the present invention to provide a novel coating composition that can provide a film without impairing various excellent functions and can be cured in one liquid. [0004] 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 at least one free isocyanate group, a polysiloxane compound having a reactive organic functional group, and an organic polyisocyanate, which has at least one free isocyanate group. A coating composition characterized in that it contains a fluorine-containing resin modified with a modifier having as a film-forming component. [Function] By modifying the film-forming fluorine-containing resin with a specific silane coupling agent and a specific modifier, the fluorine-containing resin is It is possible to provide a coating composition that can provide a coating that exhibits the excellent performance inherent to resins and can be cured in one liquid. [Preferred Embodiment] Examples of the silane coupling agent having at least one free isocyanate group used in the present invention include the following compounds. [Formula 1] (R1 is a lower alkyl group, R is a lower alkyl group or a lower alkoxy group, R3 is a C1 to C6 alkyl group, m=
(an integer of 1 to 3, n=3-m) Further, as preferred examples of the polysiloxane compound having a reactive organic functional group used in the present invention, the following various compounds can be mentioned. (1) Amino-modified polysiloxane oil [
Chemical formula 2] [Chemical formula 3] [Chemical formula 4] [Chemical formula 5] [Chemical formula 6] [Chemical formula 7] [Chemical formula 7] embedded image The above epoxy compound can be used by reacting with a polyol, polyamide, polycarboxylic acid, etc. so that it has terminal active hydrogen. (3) Alcohol-modified siloxane oil [
(4) Mercapto-modified siloxane oil
(5) Carboxyl-modified siloxane oil (25) [26] [27] [28] Reactive organic compounds listed above Two types of compounds, a silane coupling agent having a functional group and a polysiloxane compound, are examples of preferred compounds used in the present invention, and the present invention is not limited to these examples. Therefore, in addition to the above-mentioned exemplified compounds, any other known compounds that are currently commercially available and can be easily obtained from the market can be used in the present invention. As the organic polyisocyanate to be reacted with the polysiloxane compound used in the present invention, any conventionally known organic polyisocyanate can be used, but preferred ones include toluene-2,4-diisocyanate and 4-methoxy −
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, 4,4-methylenebis(phenylisocyanate), julylene diisocyanate, 1,5-naphthalene diisocyanate, benzidine diisocyanate, o-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, adducts of these organic polyisocyanates and other compounds include, for example, those having the following structural formulas, but are not limited thereto. [Chemical 29] (Hereafter the blank space) [Chemical 30] [Chemical 31] [Chemical 32] [Chemical 33] [Chemical 34] [Chemical 35] In addition, these organic polyisocyanates and low molecular weight polyols or polyamines can be combined into terminal isocyanates. Naturally, urethane prepolymers obtained by reacting in the following manner can also be used in the present invention. The modifier used in the present invention is a polysiloxane compound having a reactive organic functional group as described above and an organic polyisocyanate as described above, in which the organic functional group and the isocyanate group are contained in one molecule. With a functional group ratio of one or more isocyanate groups, preferably an excess of 1 to 2, in the presence or absence of an organic solvent and a catalyst, about 0 to 1
About 10 minutes at a temperature of 50°C, preferably 20-80°C
It can be easily obtained by reacting for 3 hours. [0016] 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 directly used to modify the fluorine-containing resin. This is advantageous because it can be used for. 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 are:
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., and also acetone, cyclohexane,
Tetrahydrofuran, dioxane, methanol, ethanol, isopropyl alcohol, butanol, toluene, xylene, dimethylformamide, dimethyl sulfoxide, perchloroethylene, trichlorethylene, methyl cellosolve, butyl cellosolve, cellosolve acetate, etc. can also be used. The paint solvent used in the present invention is a solvent commonly used in paints, and includes, for example, the solvents exemplified above. Various types of fluorine-containing resins are commercially available, which are used as film-forming resins in the present invention and are modified with the above-mentioned silane coupling agent and specific modifier. Any of these commercially available fluorine-containing resins can be used in the present invention as long as they have the following properties and are soluble in solvents. Examples of such fluorine-containing resins include fluorine-containing olefin monomers such as tetrafluoroethylene and trifluorochloroethylene, and monomers having isocyanate-reactive functional groups such as hydroxyl groups, carboxyl groups, amino groups, or epoxy groups. Examples include copolymers of For example, typical examples of copolymerizable monomers include:
Various alkyl vinyl ethers can be mentioned. The coating composition of the present invention has the above-mentioned components as essential components, and their blending ratio is such that the solvent has a total solid content of 5.
The film-forming fluororesin accounts for about 5 to 30% by weight in 100 parts by weight of the paint, and the silane coupling agent and the modifier account for 100 parts by weight of the fluororesin. A range of 1 to 100 parts by weight per part by weight is preferred. Incidentally, the silane coupling and the reaction between the modifier and the fluorine-containing resin may be carried out before or after the preparation of the coating material, and are not particularly limited. Furthermore, the coating composition of the present invention, like other general coatings, contains extender pigments, organic pigments, inorganic pigments, other film-forming resins, plasticizers, ultraviolet absorbers, antistatic agents, and leveling agents. , a curing agent, a catalyst, 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, etc. Resin, vinyl chloride/vinyl acetate/vinyl alcohol copolymer resin, alkyd resin, epoxy resin, acrylonitrile-butadiene resin, polyurethane resin, polyurea resin, nitrocellulose resin, polybutyral resin, polyester resin , melamine resins, urea resins, acrylic resins, polyamide resins, etc., and in particular, 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. 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. When the coating composition of the present invention is brought into contact with moisture in the air, water, steam, etc., the silanol groups undergo a crosslinking reaction and are cured. Catalysts for promoting this silanol condensation are generally alkyl titanates, tin octylate, carboxylic acid salts such as dibutyltin dilaurate, amino salts such as dibutylamine-2-ethylhexoate, and other acidic acids. Catalysts and basic catalysts are preferred. The amount used is 0.0001% by weight ~
A range of 5% by weight is preferred. Further, when curing the coating composition of the present invention, curing may be performed by using a curing agent such as isocyanate or melamine in combination. The content of silanol groups due to modification is preferably in the range of 0.1% by weight to 60% by weight, but when considering the transparency of the paint, it is 0.1% by weight.
More preferably, the content is 30% by weight. The coating composition of the present invention can be cured in one liquid by contacting with moisture in the air, water, steam, etc., and also maintains the inherent surface hardness, gloss, and weather resistance of fluorine-containing resin coatings. , solvent resistance, stain resistance, etc.
It is possible to provide a paint base that is as good as that obtained by curing a fluorine-containing resin with a curing agent such as melamine or isocyanate. The coating composition of the present invention can be used alone or with a primer to coat not only metals such as steel plates, aluminum plates, and aluminum sashes, but also inorganic materials such as glass, cement, and concrete, FRP, polyester, polyethylene, polypropylene, It is useful for coating various plastics such as nylon, vinyl chloride resin, acrylic resin, and various types of wood. [Examples] Next, the present invention will be explained in more detail with reference to 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 (Production of Modifier) 15.1 parts of isophorone diisocyanate, 0 parts of dibutyltin dilaurate
．． 005 parts of ethyl acetate and 70 parts of ethyl acetate were gradually added dropwise to 150 parts of polydimethylsiloxane (molecular weight 2,200) having a terminal hydroxyl group having the structure shown below while stirring well at 80°C. embedded image After the reaction was completed, ethyl acetate was removed by evaporation to obtain 162 parts of transparent liquid modifier (I). Obtained modifier (I)
According to the infrared absorption spectrum, absorption due to free isocyanate groups is observed at 2270 cm-1, and
An absorption band based on -SiO- was shown at 090 cm-1. Furthermore, when the amount of free isocyanate groups in this modifier was quantified, the theoretical value was 1.73%, whereas the actual value was 1.61%. Therefore, the main structure of the above modifier is estimated to be the following formula. ##STR37## Reference Example 2 (Production of modifier) Water-added MDI2
1.4 parts of butyltin dilaurate, 0.006 parts of ethyl acetate, and 86 parts of ethyl acetate were mixed at 80°C with good stirring, and into this was added polydimethylsiloxane with the same terminal hydroxyl group as used in Reference Example 1 (molecular weight 2200). 180 parts were gradually added dropwise to react. After the reaction was completed, ethyl acetate was removed by evaporation to obtain 194 parts of transparent liquid modifier (II). According to the infrared absorption spectrum of the obtained modifier (II), absorption due to free isocyanate groups was observed at 2270 cm-1, and an absorption band based on -SiO- was observed at 1090 cm-1. In addition, when the free isocyanate group in this modifier was quantified, the theoretical value was 1.70.
%, whereas the actual value was 1.58%. Therefore, the main structure of the above modifier is estimated to be the following formula. [Chemical formula 38] Reference example 3 (modification of resin) Fluoroolefin-vinyl ether copolymer resin solution (
Solid content 50%, hydroxyl value 24 mgKOH/g, manufactured by Asahi Glass (Lumiflon) 300 parts, and a silane coupling agent (CH3O)3Si(CH2) having an isocyanate group.
20 parts of 3NCO (Shin-Etsu Chemical (KBM-9007)) and 3 parts of the modifier (I) of Reference Example 1 were added and reacted at 80°C for 7 hours to obtain a fluorine-containing resin solution modified with the modifier. According to an infrared absorption spectrum, the modified resin thus obtained had an absorption band based on -SiO- at 1090 cm-1, but no absorption due to isocyanate groups (2270 cm-1) was observed. This is presumed to be due to graft bonding of the coupling agent to the resin. Reference Example 4 (Modification of resin) Fluoroolefin-vinyl ether copolymer resin solution (
A silane coupling agent (C2H5O)3Si(CH2
) 24 parts of 3NCO (Shin-Etsu Chemical (KBE-9007)) and 4 parts of the modifier (I) of Reference Example 1 were added and reacted at 80°C for 7 hours to obtain a fluorine-containing resin solution modified with the modifier. According to an infrared absorption spectrum, the modified resin thus obtained had an absorption band based on -SiO- at 1090 cm-1, but no absorption due to isocyanate groups (2270 cm-1) was observed. This is presumed to be due to graft bonding of the coupling agent to the resin. Reference Example 5 (Resin Modification) A silane cup having an isocyanate group was added to 300 parts of a trifluorochloroethylene copolymer resin solution (solid content 50%, hydroxyl value 25 mgKOH/g, manufactured by Central Glass (Selfful Coat)). Ring agent (CH3O)2CH3Si(CH2
) 18 parts of 3NCO (Shin-Etsu Chemical (KBE-9007)) and 4 parts of the modifier (I) of Reference Example 1 were added and reacted at 80° C. for 7 hours to obtain a fluorine-containing resin solution modified with the modifier. According to an infrared absorption spectrum, the modified resin thus obtained had an absorption band based on -SiO- at 1090 cm-1, but no absorption due to isocyanate groups (2270 cm-1) was observed. This is presumed to be due to graft bonding of the coupling agent to the resin. Examples 1 to 3 and Comparative Examples 1 to 3 Reference Example 3 to
The modified fluorine-containing resin solution of No. 5 was made into a paint according to the formulation shown in Table 1 according to a conventional coating method to obtain coating compositions of Examples 1 to 3 of the present invention. Table 2 shows the results of physical property tests for each item using this material. In Comparative Examples 1 to 3, the unmodified resin solutions of Reference Examples 3 to 5 were used for coating film formation, and isocyanate was used as a curing agent. In addition, various physical property tests of the coating composition of the present invention were carried out by coating it on a zinc steel plate (treated with phosphoric acid) to a dry thickness of 25 μm and leaving it at room temperature (23°C, 46% humidity) for 10 days. It was dried and used for each of the tests described below. Stain resistance (*1) - Lipstick, crayon... Wipe off with a dry cloth - Magic (dry cloth wipe)... Wipe off with a dry cloth (solvent wipe)... Petroleum Benzine/ethanol = 5
Wipe off with a mixed solvent of 0/50 (weight ratio) <Judgment criteria> Lipstick resistant
Crayon resistant Magic resistant ◎ No marks left Same as left
Same as left ○
There is a very slight mark Same as left
Same as left
△ Leaves a lot of marks and is difficult to remove Same as left Same as left
× Leaves no trace
Same as left
Same as left Surface properties (*2) ・Water repellency...Contact angle (°) ・Falling angle...The angle at which water droplets begin to slide when the coated sample is tilted (Water repellency and falling angle measurements are both consistent) (Using a contact angle meter manufactured by Kaimen Kagaku Co., Ltd.) ・Cellotape peeling: After pressing Cellotape (Nichiban) onto the coated surface with a constant pressure, measure the peeling force at 25°C for 3 days (JIS C2107) Table 1
Example Comparative example
1 2 3 1
2 3 Resin (solid content 5
0%) 100 100 100 100
100 100 Methyl ethyl ketone
75 75 75 75 7
5 75 xylene
25 25 25 25
25 25 Titanium oxide (CR-09)
20 20 20
20 20 20 Coronate EH (Nippon Polyurethane) − −
- 8.6 9.3 9.0
Diffyltin dilaurate (*3) 0.
001 0.001 0.001 0.00
04 0.0004 0.0004*3: The amount of dibutyltin dilaurate was adjusted to the same final amount in consideration of the amount added at the time of producing the modifier. Table 2
Example
Comparative example
1 2 3
1 2 3 Gloss (60
°Gross) 74 74 75
79 81 78 Adhesion (copper tape peeling) 100
/100 100/100 100/100 100/
100 100/100 100/100 Stain resistance (*1) Lipstick ◎
◎ ◎ ◎ ◎
◎Crayon ◎
◎ ◎ ◎
◎ ◎Magic (dry cloth wipe) ◎ ◎
◎ × × ×
(Wipe off solvent) ◎ ◎
◎ ◎ ◎
◎ Surface properties (*2) Water repellency 97.2
96.5 98.0 78.0
80.2 77.8 Falling angle (°)
20-40 20-40 20-40 40
~50 40~50 40~50 Static friction coefficient
0.12 0.14 0
．． 16 0.44 0.41 0.
39 Cello tape peeling (g/cm)
19 14 18 28
5 306 322 [Effects] As described above, the coating composition of the present invention has good solubility in general coating solvents, but does not have the stain resistance and abrasion resistance inherent to fluorine-containing resins. It is possible to provide a coating that can exhibit excellent properties such as non-adhesiveness and slipperiness. or,
It is a coating composition that can be cured in one component, and the above-mentioned excellent properties are not impaired.

Claims (2)

[Claims] 1. A reaction product of a silane coupling agent having at least one free isocyanate group, a polysiloxane compound having a reactive organic functional group, and an organic polyisocyanate, the reaction product having at least one free isocyanate group. 1. A coating composition comprising, as a film-forming component, a fluorine-containing resin modified with a modifying agent. 2. The coating composition according to claim 1, further comprising water as a curing agent.