JPH05214276A - Leather-like coating material - Google Patents

Abstract

PURPOSE:To provide a leather-like coating material capable of giving a crack- free coating film having excellent moisture retention breathability and touch similar to those of a leather surface and a sufficient strength when applied to an object material to which the above-mentioned properties similar to those of a leather can be imparted. CONSTITUTION:A leather-like coating material comprises 90-40wt.% film-forming material and 10-60wt.% esterified polypeptide prepd. by esterification of a polypeptide through a reaction thereof with a polyfunctional alcohol to effect chain extension of carboxyl groups as the side chains of the polypeptide, or polypeptide deriv. obtd. through a reaction of functional groups originating in the polyfunctional alcohol moieties present in the side chains of the above-mentioned esterified polypeptide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leather-like paint which gives a paint surface having a moisturizing property, a breathability and a touch feeling similar to a leather surface.

[0002]

BACKGROUND OF THE INVENTION Generally, a paint is a coating film-forming material composed of natural resin and synthetic resin and a solvent,
It is composed of a plasticizer, a curing agent, an emulsifier, a thickener, a pigment, a dye and the like, and the desired coating film properties can be obtained by appropriately selecting the above components. However, in addition to imparting beauty to the object to be coated, conventional coating materials can be provided with surface protection, that is, moisture resistance, rust prevention, corrosion resistance, chemical resistance, and oil resistance, but moisturizing properties similar to leather surface, It cannot have breathability and feel. On the other hand, in order to solve this problem, a method of mixing leather powder and gelatin powder into the paint has been proposed (Japanese Patent Laid-Open No. 62-257975). There is a problem that it is difficult to form a film having sufficient strength because of poor compatibility and adhesive strength.

The present inventors have noticed that blending a leather powder and a gelatin powder can improve the moisturizing property, breathability and touch feeling similar to the leather surface on the coated surface, and the characteristics of these materials are taken into consideration. A search was made for a material which, while making the best use of it, has a sufficient coating film strength.

[0004]

Means for Solving the Problems As a result of various investigations in view of the above situation, the inventors of the present invention have made it possible to react a polypeptide with a polyfunctional alcohol for esterification, and to carry out esterification to form a carboxyl group on the side chain of the polypeptide. If the ester derivative of the chain-extended polypeptide, or the polypeptide derivative obtained by further reacting the functional group derived from the polyfunctional alcohol present in the esterified side chain of the polypeptide is added to the paint, The inventors have found that a skin-like paint having a similar moisturizing property, breathability, touch feeling, and a coating film having sufficient strength without cracks can be obtained, and the present invention has been completed.

That is, the gist of the present invention is to carry out esterification by reacting a polypeptide with a polyfunctional alcohol to form an esterified product of a polypeptide in which the carboxyl group of the polypeptide side chain is extended, or an ester of the above-mentioned polypeptide. Polypeptide derivatives 10 to 6 obtained by further reacting a functional group derived from a polyfunctional alcohol present in the compound side chain
0% by weight and 90 to 40% by weight of a coating film-forming material.

Specific examples of the esterification product or polypeptide derivative of the polypeptide used in the present invention include the following. (1) An esterification product of a polypeptide in which a carboxyl group of a polypeptide side chain is chain-extended by reacting an aqueous solution of a polypeptide, a fine powder or a suspension thereof with excess polyfunctional alcohol to effect esterification, ) Polypeptide derivative obtained by reacting a compound having an isocyanate group with a hydroxyl group derived from a polyhydric alcohol existing in a chain-extended side chain by using a polyhydric alcohol as the polyfunctional alcohol, (3) a polyfunctional alcohol Polyhydric alcohol is used as the compound, a compound having an epoxy group on a hydroxyl group derived from the polyhydric alcohol present in the chain-extended side chain is reacted, and then it is resinified into a polypeptide derivative, and (4) as a polyfunctional alcohol Using an alcohol having an unsaturated bond, the unsaturated group derived from the alcohol present in the chain-extended side chain In the presence of a polymerization initiator, addition polymerization of vinyl monomer,
Alternatively, a synthetic polymer is graft-polymerized, or a synthetic polymer is graft-polymerized with an esterification product of a polypeptide having the unsaturated group, a polypeptide derivative,

In order to synthesize such an esterified product or polypeptide derivative of the polypeptide used in the present invention, as a first step, a polyfunctional alcohol is added to the carboxyl group of the side chain of amino acids constituting the polypeptide. And the chain is extended by esterification to prepare an esterified product of a polypeptide having a functional group derived from a polyfunctional alcohol in the side chain of the polypeptide. Then, as the second step, in the first step, in an organic solvent, such as toluene, dimethylformamide, ethyl acetate, tetrahydrofuran, cyclohexane, dimethylsulfoxide, etc., which has conventionally been used with poor affinity for the polypeptide itself and was rarely used. The obtained esterified product is combined with a so-called conventional polymerization technique such as addition polymerization of a raw material compound of epoxy resin or urethane resin or other polymerizable vinyl monomer, or graft polymerization with a synthetic polymer to obtain a polypeptide derivative. To manufacture.

Such a manufacturing method will be described in detail for each mode. (1) First embodiment (Production of esterification product of polypeptide): Aqueous solution of polypeptide, fine powder or suspension thereof is allowed to react with excess polyfunctional alcohol to effect esterification. An esterification product of the polypeptide can be produced by chain-extending the carboxyl group. The polypeptide used in the present invention is
It is not particularly limited, and examples thereof include gelatin, collagen, casein and the like. In addition, chrome-tanned leather-like leathers containing these polypeptides, such as cowhide, pigskin and sheepskin, may be used as they are.

In the present invention, an esterified product of a polypeptide can be obtained by adding a polyfunctional alcohol to an aqueous solution of a polypeptide, a fine powder or a suspension thereof to carry out an esterification reaction. Examples of the polyfunctional alcohol used herein include polyhydric alcohols such as diethylene glycol, triethylene glycol, polyethylene glycol, glycerin or butanediol and propanediol, or allyl alcohol, hydroxyethyl acrylate, hydroxyethyl methacrylate, 4
Examples thereof include alcohols having an unsaturated bond such as allylcatechol and allylcarbinol, and may be alcohols having an epoxy group.

The amount of these polyfunctional alcohols used is
Although not particularly limited, an excess amount is usually used with respect to the carboxyl group in the polypeptide, and specifically, an amount of 0.0015 to 0.1 mol per 1 g of the polypeptide is an appropriate amount. Esterification is usually performed at a reaction temperature of 10
The reaction time can be arbitrarily set in the range of up to 100 ° C., and the time required for the reaction is not uniquely determined because the esterification rate can be arbitrarily selected depending on the amount of the polyfunctional alcohol used and the reaction temperature, but it is usually 1 hour. Selected within a range of up to 4 days.
By reacting these polyfunctional alcohols with the above-mentioned polypeptide, glutamic acid (G
The side chain carboxyl groups such as lu) and aspartic acid (Asp) are esterified to extend the chain. In the chain thus extended, esterification products of polypeptides having various functional groups derived from polyfunctional alcohols are obtained.
For example, among the above polyfunctional alcohols, when a polyhydric alcohol is used, an esterified product of a polypeptide having a hydroxyl group in the extended chain is obtained, and when an alcohol having an unsaturated bond is used, Gives an esterified product of a polypeptide having an unsaturated group in the extended chain.

(2) Second mode (production of polypeptide derivative): In the above-mentioned first mode, a polyhydric alcohol is used as the polyfunctional alcohol, and a hydroxyl group derived from the polyhydric alcohol is used as a chain-extended side chain. A polypeptide derivative can be produced by synthesizing an esterified product of a polypeptide having the following formula and then reacting the compound having an isocyanate group with the hydroxyl group to form a urethane. Examples of the polyhydric alcohol used here include alcohols having two or more hydroxyl groups in the molecule, such as diethylene glycol, triethylene glycol, polyethylene glycol, glycerin or butanediol, propanediol among the above-mentioned polyfunctional alcohols. Is mentioned. The method for urethane-forming the hydroxyl group present in the extended side chain of the obtained esterified product is carried out by reacting the esterified product with a compound having an isocyanate group. Specifically, for example, the esterified product may be reacted with a compound having an isocyanate group and then urethanized with a polyol or a diamine. Further, as a compound having an isocyanate group, a prepolymer having a terminal diisocyanate may be used to react with the esterified product to form a urethane, thereby obtaining a polypeptide derivative. The compound having an isocyanate group, the polyol, and the diamine used here can be selected according to the purpose and are usually general-purpose ones.

(3) Third Mode (Production of Polypeptide Derivative): In the above-mentioned first mode, a polyhydric alcohol is used as the polyfunctional alcohol, and a hydroxyl group derived from the polyhydric alcohol is used as a chain-extended side chain. A polypeptide derivative can be produced by synthesizing an esterified product of a polypeptide having ## STR4 ## and then reacting a compound having an epoxy group with the hydroxyl group and further converting it into a resin. As the polyhydric alcohol used here, the same one as in the case of the second aspect is used. As the compound having an epoxy group, for example, epichlorohydrin and the like can be mentioned, and after the esterification product is epoxidized using this, for example, polyhydric phenol may be reacted to be resinified sequentially, or terminal epoxidized. The resin may be reacted with the hydroxyl group of the esterified product to give a polypeptide derivative.

(4) Fourth Aspect (Production of Polypeptide Derivative): In the above-mentioned first aspect, an alcohol having an unsaturated bond is used as the polyfunctional alcohol, and an unsaturated bond is added to the side chain extended. Or an esterified product of a polypeptide having an unsaturated group derived from an alcohol, and then addition-polymerizing a vinyl monomer to the unsaturated group in the presence of a polymerization initiator, or graft-polymerizing a synthetic polymer, or A polypeptide derivative can be produced by graft-polymerizing an esterified product of the polypeptide having the unsaturated group onto a synthetic polymer. As the alcohol having an unsaturated bond used here,
The allyl alcohol, 4-allyl catechol, allyl carbinol etc. which were mentioned above are mentioned. There are various methods for producing a polypeptide derivative using such an esterified product having an unsaturated group. For example,
Examples thereof include a method of performing addition polymerization with various polymerizable vinyl monomers using a conventional polymerization initiator, a graft polymerization of a synthetic polymer with an esterified product, and a graft polymerization of the esterified product with a synthetic polymer.

As the above-mentioned polymerization initiator, for example, benzoyl peroxide, azoisobutyronitrile, etc. are used, and further, known polymerization techniques utilizing radiation polymerization, ultraviolet polymerization or polymerization by mechanochemical reaction are used. Good. Further, as the polymerizable vinyl monomer, vinyl chloride, ethylene, styrene, methyl methacrylate, butadiene, chloroprene, and the like, as well as a silicon-based monomer can be used. In the above or, in the unsaturated group of the esterified product is cleaved by a polymerization initiator on the synthetic polymer or synthetic polymer molded article, the esterified product is grafted to the synthetic polymer, or vice versa. It is carried out by grafting onto the esterified product. As the polymerization initiator used here, the same ones as listed above can be used. Further, examples of the synthetic polymer include polyvinyl chloride, polyethylene, polyamide resin, silicon rubber, polybutadiene rubber, chloroprene rubber, and thermoplastic rubber. However, rubber can be grafted with a vulcanized product, but its effect is smaller than that of an unvulcanized product.

The polypeptide derivative in the present invention is obtained by each of the second to fourth aspects using the esterified product obtained by the first aspect as described above as an intermediate. The structural feature of the polypeptide derivative thus obtained is that the side chain of the polypeptide has a urethane bond (obtained in the second mode) and the side chain of the polypeptide is epoxidized (third mode). And a synthetic polymer bound to the side chain of the polypeptide (4th
(Obtained in the form of)).

The use of such an esterified product or polypeptide derivative of a polypeptide as a coating material is carried out by mixing it with a coating film-forming material. Examples of the coating film-forming product used in the present invention include natural resins such as rosin and gum, alkyd resins, acrylic resins, epoxy resins, polyamide resins, polyurethane resins, unsaturated polyester resins, synthetic resins such as vinyl resins, There is no particular limitation and either may be used. Further, these coating film-forming products may be used alone or in combination of two or more. The mixing ratio of the esterification product or polypeptide derivative of the polypeptide and the coating film-forming product is 90 to 40% by weight based on the solidification product of the esterification product or polypeptide derivative of the polypeptide and 10 to 60% by weight. The range is appropriate. If the amount of the esterified product or polypeptide derivative of the polypeptide is less than 10% by weight, the desired moisturizing property, breathability and touch feeling on the surface of the leather cannot be obtained, and if it exceeds 60% by weight, the strength of the coating film decreases. It is not desirable because it will come.

The type of coating film-forming material is appropriately selected according to the desired physical properties of the coating film, but if necessary, a solvent, a plasticizer, a curing agent, an emulsifier, a thickener, a pigment, a dye or the like is used in an appropriate amount. The solvent is not particularly limited, but for example, toluene, xylene, ethyl acetate, methyl ethyl ketone, etc. are usually used. The esterification product or polypeptide derivative of the polypeptide and the coating film-forming product and other necessary additives can be mixed by a conventional method using a sand mill, a ball mill, a multi-axis roll or the like.

[0018]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Production Example 1 A 500 ml separable flask equipped with a stirrer was treated with an alkali-treated gelatin (Konica Gelatin Co., Ltd., molecular weight: about 10).
45 g (dry matter) of 10,000 alpha gelatin) is added, and this is dissolved in 100 ml of distilled water. Next, 50 ml of allyl alcohol was added and reacted at 50 ° C. for 24 hours. In order to recover the esterified product, water as a solvent and excess allyl alcohol that did not participate in the reaction were evaporated under reduced pressure at 50 ° C., and subsequently, they were completely dried and removed under reduced pressure at 80 ° C. for 24 hours. The obtained esterified product was dissolved again in 100 ml of distilled water, and the same operation as above was repeated 3 times. As a result, the yield of the esterified product reached a constant amount. The final yield was 48 g. The fine powder obtained is a diffuse reflection method F.
The absorption at 1724 cm ⁻¹ by T-IR and the color reaction with hydroxamic acid-iron (III) confirmed the presence of an ester bond from the color change from yellow to magenta. Further, it was found from a 200 MHz NMR analysis that about 91% of the carboxyl groups of gelatin were esterified products of gelatin (gelatin / allyl alcohol).

Production Example 2 51 g of chrome-tanned leather (cowhide) powder pulverized to about 10 μm or less in terms of dry matter was put in a 500 ml separable flask equipped with a stirrer together with 50 ml of allyl alcohol to make a suspension, and stirred at 50 ° C. The reaction was carried out for 24 hours. Next, excess allyl alcohol was distilled off under reduced pressure and then completely distilled off under reduced pressure at 40 ° C. for 24 hours. The obtained esterified product was washed with 100 ml of distilled water,
A small amount of alcohol was removed by the same method as in Production Example 1.
As a result of repeating this operation three times, the yield of the esterified product (chromic tanned leather / allyl alcohol) reached a constant amount.
The final yield obtained was 52.4 g, and the esterification rate due to weight increase was about 37%.

Production Example 3 50 ml in a 500 ml separable flask equipped with a stirrer
Diethylene glycol and 53 g casein (reagent 1
Grade) and 0.1 N HCl (50 ml) were added, and the reaction was performed while maintaining the temperature at 50 ° C. with stirring. After reacting for 24 hours, the reaction was stopped, the reaction product was precipitated in methanol, and washed repeatedly with water to completely remove diethylene glycol that did not participate in binding. This was air-dried and further dried under reduced pressure to remove a trace amount of water. As a result, 5
3.6 g of esterified product (casein / diethylene glycol) was obtained.

Production Example 4 40 g of the esterified product (gelatin / allyl alcohol) obtained in Production Example 1 and 100 ml of a 2 mmol / liter toluene solution of a radical initiator benzoyl peroxide (hereinafter referred to as BPO) were mixed with 1 liter equipped with a stirrer. After being placed in a separable flask, 38 g of styrene monomer and 250 ml of toluene were further added, and after substitution with nitrogen, reaction was carried out at 80 ° C. for 3 hours. Then, methanol was added to stop the reaction, and the styrene monomer in the obtained graft product and polystyrene not involved in the binding were removed by washing with acetone to give 43 g of a polypeptide derivative (gelatin / polystyrene graft product). Obtained.

Production Example 5 A 300 ml separable flask equipped with a stirrer was charged with 50 g of vinyl chloride powder and 4.5 g of the esterified product (gelatin / allyl alcohol) obtained in Production Example 1, and then 3 m.
1 ml of a dimethylsulfoxide solution of mol / liter BPO and 50 ml of toluene were added and reacted at 80 ° C. for 3 hours. After filtering through Nutze, it was thoroughly washed with ethanol and then dried to obtain 54.3 g of a polypeptide derivative (gelatin / vinyl chloride graft product).

Production Example 6 86% of gelatin obtained in the same manner as in Example 3 except that butanediol was used in place of diethylene glycol and gelatin was used in place of casein.
The esterified product (gelatin / butanediol) was dried under reduced pressure at 80 ° C. for 24 hours to remove water, and then 10.2
g was dissolved in dimethyl sulfoxide to give a solution of about 15%. While stirring this solution, tolylene diisocyanate was added with the equivalent ratio of -NCO / OH being 1.02 to obtain a polypeptide derivative (gelatin / urethane compound complex).
Got

Production Example 7 50 g of an esterified product (gelatin / butanediol) obtained in the same manner as in Production Example 6 and 2 g of caustic soda were added to 250 m.
It was dissolved in 1 l of distilled water. On the other hand, 20 ml of epichlorohydrin was placed in a three-necked flask equipped with a dropping funnel containing 50 ml of dimethyl sulfoxide and a condenser. Next, a caustic soda solution of the esterified product was dropped from the dropping funnel over about 10 minutes, and the reaction was carried out for 5 hours while stirring. After the reaction, the mixture was poured into excess acetone, filtered, washed, and then vacuum dried to obtain an esterified epoxidized intermediate. Subsequently, 40 g of this epoxidized intermediate was dissolved in 250 ml of dimethylsulfoxide. This solution was placed in a three-necked flask equipped with a condenser and a dropping funnel, heated to 50 ° C., and 85 mmol of bisphenol A was added. After dissolution, gradually add a 40% caustic soda solution in an equimolar amount to bisphenol A,
The reaction was carried out for 6 hours. After stopping the reaction, the reaction product was filtered with excess acetone and washed repeatedly.

Next, in order to remove the caustic soda contained therein, the reaction product was put into a bisking tube and the pH was adjusted.
After dialysis in a sodium borate solution of 7.2 for 2 days,
When dried, about 53 g of product was obtained. In order to modify 53 g of this into a curable resin, the same procedure as the above-mentioned epoxidized intermediate was repeated to obtain a polypeptide derivative (polypeptide / epoxy compound complex) having epoxidized terminal hydroxyl groups. ) Got.

Production Example 8 46.8 g of the esterified product (casein / diethylene glycol) of Production Example 3 which was dried under reduced pressure at 60 ° C. for 24 hours to remove water and 100 ml of dimethyl sulfoxide were placed in a reaction vessel. Next, while stirring the solution with a stirrer, 9.52 g of butanediol and 100 ml of
Dimethylsulfoxide solution of No. 3, and then 3.6.
A solution of g of diphenylmethane diisocyanate in 50 ml of dimethylformamide was added. Next, the reaction vessel was heated to 50 ° C. and reacted for about 2 hours, then the reaction product was precipitated in methanol to recover the polymer, and the unreacted mixture remaining in the polymer was soaked with ethyl acetate for 24 hours. Extracted. As a result, the resulting polypeptide derivative (polypeptide / urethane compound complex) is a powdery, was analyzed by FT-IR surface state by diffusion method, the urethane bond in 1740 cm ^-1, 1320 cm ^-1 , 1230 cm ⁻¹ , absorption of ester bond was observed.

Production Example 9 BPO of 3 mmol / liter in toluene was added to 50 m.
1), put this solution in a polymerization tube,
52.5 g of the esterified product (gelatin / allyl alcohol) (fine powder) obtained in Production Example 1 in which water was removed by vacuum drying for an hour was added. Further, 10 ml of a chloroprene monomer purified by a conventional method was dissolved in this toluene mixed solution, the inside of the polymerization tube was replaced with nitrogen, and then polymerization was started at 60 ° C. After performing a polymerization reaction for 6 hours, the reaction mixture was poured into methanol to collect the polymer. Soxhlet extraction was carried out for 24 hours with benzene on the monomers and homopolymers remaining in the obtained polymer. The polymer obtained by drying under reduced pressure was about 55 g, and it was found that the polymer was in a state in which rubber was bound to the surface of the polypeptide. From the difference spectrum by the diffusion method (FT-IR analysis), it was found that the chloroprene diene at 1640 cm ^-1. It was confirmed by the fact that a heavy bond was observed (polypeptide / synthetic polymer complex).

Example 1 30 g of the esterification product of gelatin / allyl alcohol obtained in Production Example 1 and 175 g of a polyurethane coating film-forming product (Mitsui Toatsu Chemicals, Inc., trade name "Orestar L228"
4 ", solid content 40%) and 45 g of methyl ethyl ketone (MEK) as a solvent were sufficiently mixed in a sand mill to obtain 250 g of a coating material. The solid content ratio of the esterification product of the polypeptide and the coating film-forming material in this paint was 30/70.
When the obtained coating material was applied to a paper with a brush and then dried, the surface had a skin-like surface and was excellent in moisturizing property, breathability and touch feeling.

Examples 2 to 9 By the same method as in Example 1, various polypeptide derivatives shown in Table 1 were mixed with a coating film-forming material to obtain various coating materials. When each paint was applied to a paper with a brush and then dried, the surface had a skin-like surface as in Example 1, and was excellent in moisturizing property, breathability, and touch feeling.

[0030]

[Table 1]

Example 10 30 g of the esterification product of gelatin / allyl alcohol obtained in Production Example 1 and 156 g of an epoxy resin coating film-forming material (manufactured by Mitsui Toatsu Chemicals, Inc., trade name "Epokey 813", solid content 45%) and As a solvent, 27 g of toluene was sufficiently mixed with a sand mill to obtain 213 g of a paint. The solid content ratio of the esterification product of the polypeptide and the coating film-forming material in this paint was 30/70. When the obtained coating material was applied to a metal with a brush and then dried, the surface had a skin-like surface as in Example 1 and was excellent in moisturizing property and touch feeling.

Example 11 Gelatin / polystyrene graft product 55 obtained in Production Example 4
100 g of acrylic emulsion-based coating film (Mitsui Toatsu Chemical Co., Ltd., trade name "ALMATEX Z115",
Solid content 45%) 10% aqueous solution of sodium hexametaphosphate 20 g, hydroxyethyl cellulose 0.4 g, water 20
g was thoroughly mixed with a sand mill to obtain a mixture (a). To 195.4 g of this mixture (a), 5 g of titanium oxide, 3 g of calcium carbonate, and 10 g of silica powder were thoroughly mixed again with a sand mill to obtain a mixture (b). 213 g of the mixture (b) and 10 g of a curing agent (manufactured by Mitsui Toatsu Chemical Co., Inc., trade name "ALMATEX H600") were mixed to obtain a coating material. The solid content ratio of the polypeptide derivative and the coating film-forming material in this paint is 55/45. When the obtained coating material was applied to an acrylic non-woven fabric with a brush and then dried, the surface had a skin-like surface as in Example 1 and was excellent in moisturizing property, breathability and touch feeling.

[0033]

Industrial Applicability The leather-like coating material of the present invention provides a coating film having a moisturizing property similar to that of a leather surface, an air permeability, a feeling of touch, and a sufficient strength without cracks. By applying the coating material of the present invention to a target material, the above-mentioned properties similar to leather can be imparted to the material.

Claims (6)

[Claims] 1. An esterification product of a polypeptide in which a carboxyl group of the polypeptide side chain is chain-extended or an esterification product side chain of the polypeptide is present by esterification by reacting a polypeptide with a polyfunctional alcohol. A skin-like coating material comprising 10 to 60% by weight of a polypeptide derivative obtained by further reacting a functional group derived from a polyfunctional alcohol and 90 to 40% by weight of a film-forming material. 2. The polypeptide derivative is urethanized by using a polyhydric alcohol as the polyfunctional alcohol and reacting a compound having an isocyanate group with a hydroxyl group derived from the polyhydric alcohol present in the chain-extended side chain. The skin-like paint according to claim 1. 3. The polypeptide derivative uses a polyhydric alcohol as the polyfunctional alcohol, and reacts a compound having an epoxy group with a hydroxyl group derived from the polyhydric alcohol present in the chain-extended side chain, and then resinified. The skin-like paint according to claim 1, which is a product. 4. The polypeptide derivative uses an alcohol having an unsaturated bond as a polyfunctional alcohol, and a vinyl monomer in the presence of a polymerization initiator in the unsaturated group derived from the alcohol present in the chain-extended side chain. The skin-like paint according to claim 1, which is obtained by addition-polymerizing the above-mentioned compound, or by graft-polymerizing a synthetic polymer, or by graft-polymerizing an esterified product of the polypeptide having the unsaturated group on the synthetic polymer. 5. The skin-like paint according to claim 1, wherein the polypeptide is gelatin, collagen or casein. 6. A skin is used as the polypeptide.
~ The leather-like paint as described in 4 above.