JPH04345676A - In-mold coating composition - Google Patents

Abstract

PURPOSE:To impart a surface texture like a natural leather to a molding and prevent a grip part of a molding, e.g. a steering wheel, from becoming sticky due to the sweat on a hand by using the title compsn. contg. a urethane resin and a specified amt. of a collagen powder. CONSTITUTION:The title compsn. of a one- or two-component type is prepd. by compounding 100 pts.wt. urethane resin dispersed in a solvent with 10-100 pts.wt. collagen powder. The resin prepd. from a polyester polyol is pref. because it gives a coating film excellent in abrasion resistance.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a urethane-based mold coating paint for imparting a leather-like design surface to molded articles.

The mold coating paint of the present invention can be used to mold coat automotive interior parts that require a matte appearance, a soft feel, and wear resistance, such as urethane steering wheels, horn pads, armrests, headrests, and instrument panels. It is suitable as a skin forming material during molding.

[0003] In this specification, the compounding unit is a weight unit unless otherwise specified.

[0004] Here, explanation will be given mainly by taking as an example a case in which a urethane handle is mold coated, but the same applies to other molded products.

[0005]

BACKGROUND OF THE INVENTION Conventionally, urethane handles have been manufactured as follows (see Figures 1 and 2).

[0006] A coating film 5 is formed by applying a urethane-based mold coating paint to the product cavity surfaces of molding molds 1 and 2 consisting of a pair of split molds. After drying the coating film 5 appropriately, the mold is closed. Urethane foam molding material is injected into the product cavity 4 formed by closing the mold (usually reaction injection molding, hereinafter abbreviated as "RIM molding").
Inject by Then, by foaming and curing the molding material, the core portion 9 is formed, and the coating film 5 is adhesively integrated with the core portion 9 and the core metal 7. When the foaming and curing is completed, the molds 1 and 2 are opened and the molded product (urethane handle) is released (see Utility Model Publication No. 53-25076, etc.).

[0007] Here, the above-mentioned mold coating paint is generally a one-component type or a two-component type. and,
In order to give the handle surface a leather-like appearance, embossing was applied to the mold.

[0008]

[Problems to be Solved by the Invention] However, the leather-like skin formed as described above has the following problems.

[0009] Molded products that have almost no moisture permeability and have gripping contact parts such as handles tend to become sticky on the hands due to perspiration.

■It is difficult to bring out the texture of natural leather, and
It also has a glossy finish, making it difficult to meet the demands of luxury and authenticity.

An object of the present invention is to provide a paint for mold coating that can solve the above-mentioned problems in mold coating molding.

0012

[Means for Solving the Problems] The mold coating paint of the present invention solves the above problems by the following structure.

[0013] In a mold coating paint in which a one-component or two-component urethane resin is dispersed in a solvent, 10 parts of collagen powder is added to 100 parts of the urethane resin.
It is characterized by being blended in a ratio of ~100 parts.

[0014]

[Detailed explanation of means]

Next, each configuration of the above means will be explained in detail.

A. The general concept of the mold coating paint of the present invention is that a one-component or two-component urethane resin is dispersed in a solvent.

(1) As a one-component type, one in which the resin component is an isocyanate prepolymer obtained by chain-extending a polyol with polyisocyanate is used. Specifically, "NV-0653" manufactured by Dainippon Ink and Chemicals Co., Ltd. can be mentioned.

(2) As a two-component type, it consists of a polyol component and a polyisocyanate (including isocyanate prepolymer) called an effect agent, and specifically, Gll
"RIM BON" manufactured and sold by iden
D" etc.

(3) As the polyol component, either polyester type or polyether type can be used. Generally, polyester-based materials are desirable because they provide excellent physical properties such as abrasion resistance.

(a) Polyester polyols include dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, and piperic acid, and an excess of diol components such as ethylene glycol, polyoxyethylene glycol, dipropylene glycol, and polyoxypropylene glycol. Those obtained by reacting with can be used, and adipic acid-based ones are usually used. .

(b) As the polyether polyol, the following bifunctional, trifunctional or higher functional polyfunctionals can be used alone or in appropriate combinations.

■Bifunctional: polyoxypropylene-polyoxyethylene glycol, polyoxyethylene glycol, polyoxypropylene glycol, polyoxybutylene glycol, ■trifunctional: propylene oxide-trimethylolpropane copolymer, propylene oxide- Hexanetriol copolymer, propylene oxide-glycerin copolymer, ethylene oxide-propylene oxide-
Glycerin copolymer, ■Tetrafunctional: ethylenediamine-ethylene oxide-
Propylene oxide copolymer (4) As the isocyanate component, commonly used ones can be used, and for example, the type and amount are appropriately selected from the following depending on the physical properties required of the molded product. Generally, when light resistance is required, such as in a handle, it is desirable to use a non-yellowing type aliphatic isocyanate.

(a) Aliphatic isocyanate In addition to the original aliphatic isocyanate, it also includes alicyclic isocyanate, such as hexamethylene diisocyanate (HMDI), xylene diisocyanate (XDI), and hydrogenated xylene diisocyanate. Nato (hydrogenated XDI), 4,4'-methylenebisdicyclohexyl diisocyanate (H12MDI), methylcyclohexyl diisocyanate (hydrogenated TDI),
and isophorone diisocyanate (IPDI), and furthermore, from the viewpoint of handling, so-called non-yellowing products such as dimers, trimers, trimethylolpropane adducts, and prepolymers made of these polymers can be mentioned. can.

(b) Aromatic isocyanate 4,4'
-Diphenylmethane diisocyanate (hereinafter referred to as “MDI”)
), crude MDI, liquid MDI, tolylene diisocyanate, phenylene diisocyanate, etc. Furthermore, from a handling standpoint, polymerized dimers, trimers, trimethylolpropane, prepolymers, etc. can be mentioned.

(5) As the above-mentioned solvent, one or more polar solvents such as methyl ethyl ketone (MEK), tetrahydrofuran (THF), isofuropyl alcohol (IPA), dimethyl formamide (DMF), ethyl acetate, and cellosolve are used. Furthermore, if necessary, a mixture of toluene, xylene, benzene, trichloroethane, methylene chloride, etc. can be used.

B. In the mold coating paint having the above-mentioned structure, the present invention requires that collagen powder be blended in a ratio of 10 to 100 parts with respect to 100 parts of urethane resin.

(1) Collagen is a type of hard protein that forms the main component of connective tissue in the body, including bones, cartilage,
"fibrous solid found in skin, fish scales, etc." (from "Iwanami Physical and Chemical Dictionary 4th Edition"). Collagen powder is
It is manufactured by the following known method.

■ Collagen fibers are prepared by selectively removing sugars and fatty acids from the skin, bones, and tendons of animals (cows, pigs, sheep, and goats) through a biochemical reaction using specific enzymes. The collagen fibers are pulverized as they are or after a crosslinking reaction has occurred. Products manufactured using this method include "CX-240" and "CX-240" from Showa Denko K.K.
Examples include those manufactured and sold under trade names such as "260" and "CX-28".

[0028] After chromium tanning the above animal skin,
Perform pulverization.

[0029] The collagen powder obtained by the production method (2) above is preferable because it does not contain chromium and does not contain impurities such as fats and sugars.

The particle size of the collagen used is 5 to 25 μm. When the particle size is less than 5 μm, the matting effect is insufficient, and when the particle size exceeds 25 μm, the mold coat application operation (usually spray application) becomes difficult.

(2) The blending amount of collagen powder is 10
If the amount is less than 50%, it is difficult to impart a leather-like appearance and moisture permeability to the epidermis. Moreover, if the amount exceeds 100 parts, the viscosity of the paint becomes too high and the application workability deteriorates, and the parts where the collagen powders come into direct contact with each other without intervening the urethane resin, that is, the collagen powders become a sea phase, and the epidermis This tends to lead to a decrease in wear resistance.

C. Molding method Mold coat molding using the above-mentioned mold coat paint containing a predetermined amount of collagen is carried out in the same manner as conventional methods. Note that the thickness of the mold coat varies depending on the physical properties, but is usually 5 to 100 μm.

[0033] In the case of IM molding the core part, the formulation of the foam molding material and the molding conditions are shown below.

Urethane foam molding material polyether polyol
100 parts glycol crosslinking agent
1
Part 8 Catalyst

2 parts Trichlorofluoromethane (Freon 11)
16 parts MDI prepolymer

65 parts RIM molding conditions injection speed 1
50g/sec, injection pressure (both liquids) 10
0kgf/cm2, injection time
4 seconds, mold temperature

50℃, curing time
2 minutes,

[0035]

[Operations and Effects of the Invention] The mold coating paint of the present invention exhibits the following functions and effects due to the above structure.

(2) Since the collagen powder 11 is dispersed in the urethane resin 12 as an island phase (see FIG. 3), the moisture permeability of the epidermis is good. Therefore, when applied to a molded product having a gripping contact portion such as a handle, stickiness caused by sweating of the hands, which conventionally occurs, is less likely to occur.

[0037] Collagen powder is made from natural leather material, and the texture can be as close as possible to natural leather not only visually but also tactilely, and it has a matte appearance. is obtained.

[0038]

[Examples] In order to better understand the present invention, the present invention will be explained below with reference to Examples.

(1) Preparation of paint for mold coating Commercially available paint for mold coating (“RIM BOND”,
Manufactured and sold by Glliden Co., Ltd., 1 urethane resin
00 parts, collagen powder ("CX-240",
The respective amounts shown in Table 1 (average particle size 20 μm) were blended.

(2) Mold coat forming After applying the mold coat paint prepared above to the product cavity surface of the mold with a spray gun so that the dry film thickness is 15 to 20 μm, molds 1 and 2 are coated. The core metal 7 is set inside, and the molds 1 and 2 are closed. Subsequently, RIM molding was performed in the product cavity 4 formed by closing the mold using the urethane foam molding material having the above composition under the above molding conditions. Physical property tests for the following items were conducted on the skin of the urethane handle after release from the mold using the methods described below.

(i) Abrasion resistance: band-shaped cotton canvas (#10
, width 40mm) with a 100g weight attached to the end of the cylinder, stroke 120mm, and 50,000 cycles/min at 60 cycles/min.
The friction was repeated several times, and the state of wear on the surface was visually observed.

(ii) Gloss: Digital variable angle gloss meter (“U
GK-5K" (manufactured by Suga Test Instruments Co., Ltd.) was used to measure the gloss (gloss) at four locations for each example and comparative example under the condition of an incident light receiving angle of 60 degrees, and the average value was determined.

(3) Test results and discussion The test results are shown in Table 1. From the results shown in Table 1, it can be seen that all the skins of molded products formed with the mold coating paint of the present invention exhibit good practical physical properties. In addition, the epidermis of each example was observed visually and by touching with sweaty hands.
In both cases, the leather-like appearance was stopped, and the hands did not feel sticky.

[0044]

[Table 1]

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a mold used when molding a urethane handle using the mold coating paint of the present invention.

FIG. 2 is a schematic cross-sectional view of a urethane handle molded using the mold coating paint of the present invention.

FIG. 3 is an enlarged view of part A in FIG. 2;

[Explanation of symbols]

1. Molding mold, 2. Molding mold, 5　　　　Mold coat coating film.

Claims (2)

[Claims] Claim 1: A mold coating paint comprising a one-component or two-component urethane resin dispersed in a solvent,
A paint for mold coating, characterized in that collagen powder is blended in a ratio of 10 to 100 parts by weight with respect to 100 parts by weight of the urethane resin. 2. The paint for mold coating according to claim 1, wherein the polyol component of the urethane resin is polyester-based.