JPH10101742A - Water-soluble copolymer and water-base coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-soluble resin additive which imparts water repellency to resins. SOLUTION: This copolymer is obtd. by copolymerizing 10-90wt.% fluoroalkyl (meth)acrylate and 90-10wt.% water-soluble vinyl compd. having a group selected from among carboxyl, carboxylate, sulfo, sulfonate, phosphoric and its salt groups, phenolic and its salt groups, quat. ammonium groups, amino and its salt groups, amide, formyl, and polyether-chain-contg. groups, has a number- average mol.wt. (in terms of polyethylene glycol) according to gel permeation chromatography of 2,000-200,000, and dissolves by at least 1wt.% in water with a pH of 3-12 at 30 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a water-soluble copolymer,
And an aqueous coating composition containing the same. More specifically, the present invention relates to a water-soluble copolymer capable of providing a water-repellent film when an aqueous coating containing the water-soluble copolymer is applied to a resin product or a metal product and dried.

[0002]

2. Description of the Related Art Conventionally, as a method for imparting water repellency to the surface of a resin product or a metal product, a method of applying a paint containing a water repellent such as polytetrafluoroethylene to the surface of the product (Japanese Unexamined Patent Publication No. Hei 8-
Nos. 73836 and 8-120212) are known. In such a method, the paint containing the water repellent is usually used in a state of being dissolved in an organic solvent. However, due to environmental problems, particularly the problem of volatile organic matter concentration regulation, there is a demand for a water-based paint that provides a water-repellent film without using an organic solvent at the time of application. However, since water repellency is originally a property achieved by being hardly compatible with water, there has been no water-based paint that imparts water repellency to a coating film.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a water-soluble copolymer which can provide a coating film formed on the surface of a resin product or a metal product with a high level of water repellency for a long time, and It is an object of the present invention to provide an aqueous coating obtained by mixing the water-soluble copolymer with a commercially available coating.

[0004]

The first aspect of the present invention is as follows.
10 to 90% by weight of a fluoroalkyl (meth) acrylate and (b) a carboxyl group or a salt thereof, a sulfone group or a salt thereof, a phosphoric acid group or a salt thereof, a phenol group or a salt thereof, a quaternary ammonium base, an amino group or a salt thereof And a water-soluble vinyl compound having a functional group selected from an amide group, a formyl group and a polyether chain-containing group, or a vinyl compound having a hydrolyzable group and 90 to 10% by weight. (Gel Permeation Chromatography) The number average molecular weight in terms of polyethylene glycol by measurement is from 2,000 to 200,000.
Which provides a water-soluble copolymer that is soluble in water in an amount of 1% by weight or more. In the second aspect of the present invention, the water-soluble copolymer is used in an amount of 0.1 to 50 in the resin component of the aqueous paint.
The purpose of the present invention is to provide a water-based paint containing 0.1% by weight.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION

(1) copolymer component (a) fluoroalkyl (meth) acrylate; a fluoroalkyl (meth) acrylate that imparts water repellency to a film [herein, the term “(meth) acrylate”
It means both “acrylate” and “methacrylate”. ] Has the general formula (I)

[0006]

Embedded image CH ₂ ＣC (R) · COOC _m H _2m C _n F _{2n + 1} (I)

[Wherein, R represents a hydrogen or methyl group, m represents an integer of 1 or 2, and n represents an integer of 5 to 10. Are preferred, and examples thereof include the following compounds.

[0008]

Embedded image CH ₂ ＣＨCH ・ COOCH ₂ CF ₃ CH ₂ ＣＨCH ・ COOCH (CF ₃ ) ₂ CH ₂ ＣC (CH ₃ ) ・ COOCH ₂ (CF ₂ ) ₄ CF
₃ CH ₂ ＣＨCH ・ COO (CH ₂ ) ₂ (CF ₂ ) ₅ CF ₃ CH ₂ ＣＨCH ・ COO (CH ₂ ) ₂ (CF ₂ ) ₅ CF
(CF ₃ ) ₂ CH ₂ ＣＨCH ・ COOCH ₂ (CF ₂ ) ₁₀ H

Particularly preferred fluoroalkyl (meth) acrylate is a compound represented by the following formula.

Embedded image

Wherein R ¹ is CH ₃ or H;
Represents an integer of 5 to 10. (B) a water-soluble vinyl compound; the water-soluble vinyl compound as the component (b) includes a carboxyl group or a salt thereof, a sulfone group or a salt thereof, a phosphoric acid group or a salt thereof, a phenol group or a salt thereof, a quaternary ammonium base, and an amino group. A water-soluble vinyl compound having a functional group selected from a group or a salt thereof, an amide group, a formyl group, and a polyether chain-containing group or a vinyl compound having a hydrolyzable group.

Specifically, (meth) acrylic acid or a salt thereof (Na, K, ammonium, etc.), styrenesulfonic acid or a salt thereof, p-vinylbenzylphosphonium sulfonate, 2-acrylamido-2-methylpropanesulfonic acid or Its salts, diacetone (meth) acrylamide, N-isopropylacrylamide, N-methylol (meth) acrylamide, N-vinylpyrrolidone,
-Vinylpyridine, 4-vinylpyridine, 4-vinylbenzoic acid, methacryloyloxyethyltrimethylammonium chloride, N-vinylformamide, an ester of acrylic acid with a sugar such as glucose or fructose, a compound having a polyether chain, for example, a polyether chain And polyethers having no hydrocarbon group in the middle or at the terminal of the following group.

[0012]

CH ₂ ５CH.COO (CH ₂ CH ₂ O) _k H CH ₂ 2C (CH ₃ ) COO (CH ₂ CH ₂ O) _k H CH ₂ kC (CH ₃ ) COO (CH ₂ CH ₂ O) _k CO
C (CH ₃ ) = CH ₂ [In the above formula, k represents an integer of 4 to 20. ]

Among these, (meth) acrylic acid or its salt, styrenesulfonic acid or its salt, 2-acrylamido-2-methylpropanesulfonic acid or its salt, methacryloyloxyethyltrimethylammonium chloride, N- Vinylformamide,
Esters of sugar and acrylic acid, and compounds having a polyether chain having no hydrocarbon group at an intermediate or terminal represented by the following general formula group are preferred.

[0014]

CH ₂ 2CHCOO (CH ₂ CH ₂ O) ₁ H CH ₂ ＣC (CH ₃ ) COO (CH ₂ CH ₂ O) ₁ H CH ₂ ＣＨCHCOO (CH (CH ₃ ) CH ₂ O) ₁ H [In the above formulas, 1 represents an integer of 5 to 10. ]

(B) a vinyl compound having a hydrolyzable group; the other vinyl compound having a hydrolyzable group of the component (b) is substantially insoluble in water,
When hydrolyzed at 0 ° C. using an acidic aqueous solution having a pH of 2.0 or an alkaline aqueous solution having a pH of 13.0, a water-soluble vinyl compound in which 75% by weight or more is hydrolyzed within 8 hours. And benzyl (meth) acrylate, vinyl acetate, and maleic anhydride. Under the above conditions, the fluoroalkyl (meth)
Acrylate is not substantially hydrolyzed, and the water-repellent copolymer is provided with water repellency. Preferably, vinyl acetate is particularly high in water solubility after hydrolysis and the degree of hydrolysis is relatively easy to control.

(2) Production of copolymer The copolymer is composed of (a) 10 to 90% by weight of a fluoroalkyl (meth) acrylate and (b) 90 to 10% by weight of a vinyl compound having a water-soluble or hydrolyzable group. And by copolymerizing The polymerization method is carried out by a known method such as radical polymerization, cationic polymerization, anionic polymerization and the like, and radical polymerization is preferred in view of easy control of the polymerization reaction. In the case of radical polymerization, the polymerization is carried out in the presence of various known radical polymerization initiators, for example, radical polymerization initiators such as benzoyl peroxide and azobisisobutyronitrile.
The copolymerization is carried out at a temperature of ９０90 ° C. for 4 to 7 hours. Further, in order to improve the affinity for the binder resin used in the water-based paint and the copolymerizability, another copolymerizable compound such as styrene, alkyl (meth) acrylate, polyester (meth) ) Acrylates, urethane (meth) acrylates and the like may be added in a proportion of less than 50% by weight.

The weight ratio of (a) the fluoroalkyl (meth) acrylate to (b) the water-soluble or hydrolysable vinyl compound is in the range of 10/90 to 90/10. When the ratio of the fluoroalkyl (meth) acrylate of the component (a) exceeds 90% by weight, a copolymer having poor water solubility is obtained, and conversely, the ratio of the water-soluble radical polymerizable compound of the component (b) is obtained. Exceeds 90% by weight, it is difficult to impart sufficient water repellency to the final coating film. However, when the water solubility must be particularly emphasized, the ratio of the water-soluble radically polymerizable compound is preferably 70 or more. When the water repellency is particularly important, the ratio of the fluoroalkyl (meth) acrylate is preferable. Should be set to 70 or more.

(3) Water-soluble copolymer The copolymer of the present invention contributes to water repellency (a)
By using a fluoroalkyl (meth) acrylate as a component and a vinyl compound as a component (b) contributing to water-solubility, water-soluble such as 1% by weight or more dissolved in 30 ° C. water of pH 3-12. A copolymer is obtained. The molecular weight of this water-soluble copolymer was measured using a mixture of 10% by weight or 40% by weight of methyl alcohol added to an acetate buffer at pH 4 under the following conditions, and GPC (gel permeation chromatography). Number average molecular weight in terms of polyethylene glycol by measurement is 2,000 to 20
000, preferably from 5,000 to 80,000.

(Conditions) Equipment: system 8010 manufactured by TOSOH (Tosoh) Column: TSKgel GMPW 1 + GP2500PW 1 manufactured by TOSOH (Tosoh) Temperature: 40 ° C. Flow rate: 1 ml / min Injection amount: 100 μl Concentration: injection concentration 0.1% by weight Detector: RI (refractometer) If the molecular weight of the water-soluble copolymer is less than 2,000, the advantage of increasing the molecular weight is lost, and the copolymer easily bleeds out of the final film. And water repellency cannot be imparted over a long period of time. On the other hand, when the molecular weight of the water-soluble copolymer is 20
If it exceeds 000, the solubility in water is inferior, which is not preferable.

(4) Aqueous paint The aqueous paint of the present invention contains the above water-soluble copolymer in an amount of 0.1 to 50% by weight in the resin component of the aqueous paint. If the amount is less than 0.1% by weight, sufficient water repellency cannot be imparted to the obtained film, while if it exceeds 50% by weight, the compatibility with other coating resin is not good. In addition, the appearance of the resulting film is impaired.

In preparing the water-based paint, the water-soluble copolymer of the present invention may be blended with a commercially available water-based paint. Further, the water-soluble copolymer of the present invention is used as a protective colloid agent when producing an acrylic resin aqueous emulsion, a vinyl acetate resin emulsion, a polyvinylidene chloride emulsion, or the like,
It may be used when preparing a water-based paint. As the aqueous paint, any known aqueous paint can be used, and examples thereof include an acrylic resin emulsion paint, a vinylidene chloride resin emulsion paint, a polyvinyl acetate emulsion paint, and an aqueous UV resin paint. Can be

The water-based paint of the present invention can be coated with various resins or metals using a known coating method, for example, a bar coating method, a roll coating method, a spray coating method, a dipping method, a spin coating method or the like. It can be applied to the surface of a molded article to be dried, dried, or irradiated with UV to form a film. The thickness of the film to be formed is 0.1 to 20
0 μm, particularly preferably in the range of 0.2 to 50 μm. When the thickness of the film is less than 0.1 to 200 μm, sufficient water repellency is not exhibited, and the durability of the film itself is poor, which is not preferable. On the other hand, when the thickness exceeds 200 μm, the cost is increased with respect to the performance obtained. Not economically favorable.

Examples of the substrate include various resin products of a thermoplastic resin or a thermosetting resin, for example, films and sheets. The thermoplastic resin is not particularly limited and includes, for example, olefin resins such as polyethylene, polypropylene, polybutene, propylene-ethylene copolymer resin, poly-4-methylpentene-1 resin, polystyrene resin, styrene-acrylonitrile resin, ABS Resins, polyester resins, polyamide resins, poly (meth) acrylate resins, polyurethane resins, and the like. Examples of the polyamide resin include nylon 6, nylon 66, nylon 610, nylon 11, nylon 12, and the like. Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, and polycarbonate. Examples of the thermosetting resin include an epoxy resin, a phenol resin, a urea resin, and a melamine resin.

Further, hydrogenated products of ethylene-propylene copolymer elastomer (EPR), ethylene-propylene-diene copolymer elastomer (EPDM), and styrene-butadiene-styrene block copolymer (SEB)
S), and various thermoplastic elastomers and rubbers such as hydrogenated styrene-isoprene-styrene block copolymer (SEPS).

The metal substrate is not particularly limited, and examples thereof include iron, aluminum, zinc, copper and the like and alloys thereof. Since the water-soluble copolymer of the present invention is water-soluble, it exhibits high compatibility with commercially available water-based paints and forms a uniform film. Therefore, the surface of a resin film, a resin sheet or a metal product having such a film formed thereon is robust and has excellent durability.

[0026]

【Example】

[Reference Example 1] Production example of acrylic resin aqueous emulsion: 48 g of methyl methacrylate, 48 g of ethyl acrylate and 4 g of acrylic acid, 3 g of sodium dodecylbenzenesulfonate as an emulsifier, and 0.5 g of potassium persulfate as a radical polymerization initiator, 230 g of water In addition, this was stirred under 85
The temperature was raised to ℃ and emulsion polymerization was carried out with an initiator for 8.5 hours to obtain an acrylic resin emulsion. The resin-based solid concentration of the acrylic resin emulsion aqueous paint was 41% by weight.

Example 1 4 g of 1H, 1H, 2H, 2H heptadecafluorodecyl acrylate (“Biscoat 17F” manufactured by Osaka Organic Chemical Industry Co., Ltd.) and polyethylene glycol monomethacrylate (“Blemmer PME400” manufactured by NOF Corporation) )) Dissolve 12 g in 48 g of methyl isobutyl ketone, add 80 mg of azobisisobutyronitrile as a radical polymerization initiator,
After the temperature was raised to ° C., polymerization was performed at the same temperature for 7 hours, and then reprecipitation was performed in hexane to obtain a copolymer.

The copolymer obtained in this manner has a pH of
It was freely mixed with 7.0 water (100% by weight dissolved). The number average molecular weight in terms of polyethylene glycol was 1.1 × 10 ^{4 as} measured by GPC (gel permeation chromatography) using a mixed solution of 10% methanol and a pH 4 acetate buffer as an eluent. FIG. 1 shows a GPC chart of the obtained water-soluble copolymer. 7 parts by weight of the water-soluble copolymer thus obtained was mixed with 244 parts by weight of the aqueous acrylic resin emulsion paint obtained in Reference Example 1 (total of the resin components was 100 parts by weight), and the polycarbonate was coated with a # 80 bar coater. It is applied on a substrate and dried to form a film having a thickness of 40 μm.
When the contact angle with water was measured in accordance with
In °, water repellency was observed.

Example 2 1H, 1H, 2H, 2H 4 g of heptadecafluorodecyl acrylate and 8 g of N-vinylformamide were dissolved in 48 g of N-methylpyrrolidone, and 80 mg of azobisisobutyronitrile was used as a radical polymerization initiator. The mixture was added, and the mixture was polymerized at 70 ° C. for 7 hours under stirring, and then reprecipitated in diethyl ether to obtain a copolymer. The obtained water-soluble copolymer is dissolved in water having a pH of 7.0.
Wt% dissolved. The number average molecular weight in terms of polyethylene glycol measured by GPC (gel permeation chromatography) using a mixed solvent obtained by adding 10% of methanol to a pH 4 acetate buffer as an eluent is 5.4 × 1.
0 was ^3. 5 parts by weight of this water-soluble copolymer was used in Reference Example 1.
Was mixed with 244 parts by weight of the acrylic resin emulsion aqueous paint obtained in the above (100 parts by weight of the total amount of resin components), applied to a polycarbonate substrate with a # 80 bar coater, and dried to form a film having a thickness of 40 μm. When the contact angle was measured, water repellency was found at 100 °.

Example 3 1H, 1H, 2H, 2H Heptadecafluorodecyl acrylate 4g, acrylic acid 8
g of polyester acrylate (PLACCEL FA-1 manufactured by Daicel Chemical Industries, Ltd.) was dissolved in 48 g of dioxane, and azobisisobutyronitrile 2 was dissolved in 48 g of dioxane.
0 mg was added as a radical polymerization initiator.
After polymerization at 7 ° C. for 7 hours, reprecipitation was performed in hexane to obtain a copolymer. This copolymer is prepared by adding 15 parts of water to pH 8.0 water.
Wt% dissolved. The number average molecular weight in terms of polyethylene glycol measured by GPC (gel permeation chromatography) using a mixed solvent obtained by adding 40% of methanol to a pH 4 acetate buffer as an eluent is 1.1 × 1.
0 was ^4. 5 parts by weight of this copolymer was mixed with 244 parts by weight of the aqueous acrylic resin emulsion paint obtained in Reference Example 1 (the total resin component was 100 parts by weight), applied to a polycarbonate substrate with a # 80 bar coater, and dried. Thickness 4
When a coating film having a thickness of 0 μm was formed and the contact angle with water was measured, water repellency was recognized at 106 °.

Example 4 1H, 1H, 2H, 2H Heptadecafluorodecyl acrylate 4g, acrylic acid 8
g of polyester acrylate (PLACCEL FA-1 manufactured by Daicel Chemical Industries, Ltd.) was dissolved in 48 g of dioxane, and azobisisobutyronitrile 2 was dissolved in 48 g of dioxane.
0 mg was added as a radical polymerization initiator.
After polymerization at 7 ° C. for 7 hours, 28% aqueous ammonia was added to 3.6
g was added to obtain a precipitate (copolymer).

The recovered copolymer was dissolved in water of pH 7.0 at 5% by weight. The number average molecular weight in terms of polyethylene glycol measured by GPC (gel permeation chromatography) using a mixed solvent obtained by adding 40% of methanol to an acetate buffer of pH 4 as eluent is 2.0 × 10
^{Was 4} . 7 parts by weight of this copolymer was mixed with 100 parts by weight of a water-soluble UV-curable resin (IRR143 manufactured by Daicel Chemical Industries, Ltd.), applied to a polycarbonate substrate with a # 28 bar coater, and then irradiated with ultraviolet rays to a thickness of 40 μm. Was formed, and the contact angle with water was measured.
, Water repellency was observed.

Comparative Example 1 1 g of 1H, 1H, 2H, 2H heptadecafluorodecyl acrylate and 1 g of N-vinylformamide were dissolved in 48 g of N-methylpyrrolidone, and 80 mg of azobisisobutyronitrile was used as a radical polymerization initiator. The mixture was added and polymerized at 70 ° C. for 7 hours with stirring, and then reprecipitated in diethyl ether to obtain a copolymer. This copolymer was substantially insoluble in water and could not be uniformly mixed with the water-based paint.

Comparative Example 2 0.1 g of 1H, 1H, 2H, 2H heptadecafluorodecyl acrylate and 15 g of acrylic acid were dissolved in 60 g of 1,4-dioxane, and 100 mg of azobisisobutyronitrile was added to a radical polymerization initiator. And polymerized at 70 ° C. for 7 hours with stirring.
The copolymer was obtained by reprecipitation in hexane. This copolymer was dissolved in water at 20% by weight. 10 parts by weight of this copolymer was mixed with 100 parts by weight of the aqueous acrylic resin paint obtained in Reference Example 1, applied to a polycarbonate substrate with a # 80 bar coater, and dried to form a film having a thickness of 40 μm. When the contact angle was measured at 71 °, no effect as a water repellent was observed.

Example 5 4 g of 1H, 1H, 2H, 2H heptadecafluorodecyl acrylate and 16 g of benzyl methacrylate were dissolved in 60 g of dioxane, and 80 mg of azoisobutyronitrile was added as a polymerization initiator. After polymerization for 7 hours, 45 g of a 0.5 M aqueous sodium hydroxide solution was added, and a precipitate (hydrolyzed copolymer) was immediately obtained.

The recovered copolymer was dissolved in water at pH 8.5 by 5% by weight. GPC using a mixed solvent obtained by adding 40% of methanol to an acetate buffer of pH 4.0 as an eluent
The number average molecular weight in terms of polyethylene glycol measured by (gel permeation chromatography) is 2.0 ×
It was 10 ⁴ . 5 parts by weight of this copolymer was mixed with 244 parts by weight of the acrylic resin emulsion aqueous paint obtained in Reference Example 1 (the total resin component was 100 parts by weight), applied on a polycarbonate substrate with a # 80 bar coater, and dried. When a film having a thickness of 40 μm was formed and the contact angle with water was measured, water repellency was recognized at 100 °.

[0037]

The water-soluble copolymer of the present invention has an extremely interesting and useful feature that, despite being water-soluble, a film obtained by mixing with a water-based paint has water repellency. .

[Brief description of the drawings]

FIG. 1 is a GPC chart of the water-soluble copolymer obtained in Example 1.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08F 230/02 C08F 230/02 C09D 5/00 C09D 5/00 A 133/16 133/16

Claims (5)

[Claims] (1) 10 to 90% by weight of (a) a fluoroalkyl (meth) acrylate and (b) a carboxyl group or a salt thereof, a sulfone group or a salt thereof, a phosphoric acid group or a salt thereof, a phenol group or a salt thereof, and a quaternary Copolymerization of 90 to 10% by weight of a water-soluble vinyl compound having a functional group selected from an ammonium base, an amino group or a salt thereof, an amide group, a formyl group, and a group containing a polyether chain, or a vinyl compound having a hydrolyzable group. And G
Number average molecular weight in terms of polyethylene glycol measured by PC (gel permeation chromatography) is 2,
000-200,000, pH 3-12 30
A water-soluble copolymer that dissolves in water at 1 ° C by 1% by weight or more. 2. A fluoroalkyl (meth) acrylate represented by the general formula (I): CH ₂ ＣC (R) .COOC _m H _2m C _n F _{2n + 1} (I) wherein R is hydrogen Or a methyl group, m represents an integer of 1 or 2, and n represents an integer of 5 to 10. Claim 1
Water-soluble copolymer of 3. The method according to claim 1, wherein the vinyl compound having a hydrolyzable group is an aqueous acidic solution having a pH of 2.0 at 30 ° C. or a pH of 13.
2. The water-soluble copolymer according to claim 1, wherein the hydrolysis rate within 8 hours in an aqueous alkaline solution of 0 is 75% or more. 4. The compound having a hydrolyzable group is benzyl acrylate, benzyl methacrylate, vinyl acetate,
2. The water-soluble copolymer according to claim 1, which is a compound selected from the group consisting of: and maleic anhydride. 5. An aqueous paint comprising the water-soluble copolymer according to claim 1 in an amount of 0.1 to 50% by weight in a resin component of the aqueous paint.