JPH0274338A - Weatherstrip for automobile - Google Patents

Abstract

PURPOSE:To apply a color other than black and to improve the adhesion of coating by a method wherein urethane coating mixed with a pigment other than black is formed, with a primer interlaid, on the surface of a vulcanized substance of an ethylene-propylene rubber compound wherein other polymers are not blended. CONSTITUTION:Ethylene-propylene vulcanized rubber includes, besides an ethylene-propylene terpolymer, an ethylene-propylene polymer or the like, another rubber component, another resin component or the like in an amount within the limits not causing the loss of the characteristics of said polymer. A vulcanizer, a vulcanization accelerator, an aging preventing agent, an oxidation preventing agent, a plasticizer, etc. are compounded in said rubber compound, but another polymer for improving adhesion is not blended in said compound. This compound is molded by an ordinary molding means and coated with polyolefin diluted to about 3% concentration by a solvent such as toluene, as a primer. After this is dried, colored urethane coating is applied on the surface and thereby a coating layer is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a weather strip for an automobile.

(Conventional technology) Currently, in addition to natural rubber, the base material for weather strips is
Chloroprene rubber, styrene-butadiene copolymer rubber, ethylene-propylene rubber, etc. are used.
Among them, ethylene, which is an ethylene-propylene rubber,
Propylene terpolymer (f!PD?I), ethylene-propylene polymer (EPR) has weather resistance, aging resistance,
They are most frequently used because of their excellent ozone resistance, and chloroprene coatings, silicone coatings, urethane paints, etc. are usually applied to these coatings as a means of improving the abrasion resistance of their surfaces.

Among these, urethane paint is considered the best option for improving wear resistance compared to other coatings and is applied to the weatherstrip surface, but ethylene-propylene rubber, which is most commonly used as a weatherstrip base material, has abrasion resistance on the surface. Even when urethane paint is applied, the adhesion between the urethane paint film and ethylene-propylene rubber is poor and it is difficult to achieve the desired purpose.In order to improve the adhesion between the two, the base material EP
A method has been proposed in which DH is blended with a polymer such as a functional hydrocarbon polymer. (Refer to Japanese Patent Publication No. 60-1192) By the way, in the case of weather stripping such as on ridges, conventionally,
The base material, such as EPDM, is usually reinforced with a carbon blank and blackened, while the urethane paint used to coat its surface is a mixture of urethane polymer with silicon oxide, carbon black, silicone, etc. Black paint is used.

(Problems to be Solved by the Invention) However, the method of blending a polymer that improves adhesion, such as a functional hydrocarbon polymer, to the base material EPDM as described above has limitations in its application, and the preferred tan paint also has weather-resistant coatings. If it were made black like the strip, it would not necessarily match the exterior and interior colors of the vehicle, and it would be impossible to respond to the diversity of market needs.

In addition, due to the diversification of user needs,
Colored EPDM molded products whose surfaces have the appearance of suede, buckskin, or fapris, and are colored in various colors have been proposed (see Japanese Patent Application Laid-open No. 59-2841), but this is based on a black EPDM base material. EPD colored in
It is a coating made of a foam made of a copolymer rubber of M and vinyl chloride, and is fundamentally different from a urethane coating even though the appearance improvement is the same.

The present invention addresses the above-mentioned circumstances and aims to diversify urethane coatings without blending polymers for improving adhesion, and to color urethane coatings other than black. The purpose of this project is to adapt to the diversity of market needs and eliminate discomfort with automobiles by finding a means to achieve this goal.

(Means for Solving the Problems) That is, a feature of the present invention that satisfies the above-mentioned object is to provide the above-mentioned automobile weatherstrip by adding another polymer, such as a conjugated diene compound and a vinyl group, to improve the adhesion of the weatherstrip. Formed from a vulcanized product of an ethylene-propylene rubber compound that is not blended with a functional hydrocarbon polymer containing a saturated aliphatic ring obtained by hydrogenation of a copolymer with an aromatized compound having In addition, a urethane paint mixed with a pigment and colored in a color other than black is coated on the surface via a primer.

Here, as the vulcanized rubber used in the automotive weather strip of the present invention, in addition to ethylene-propylene rubber, chloroblend rubber, styrene-butadiene rubber, etc. may be mentioned, but the most preferred one is the above-mentioned ethylene-propylene rubber. It is.

In addition to this ethylene-propylene vulcanized rubber x, ethylene-propylene terpolymer (EPDM) or ethylene-propylene polymer (EPR), etc.
Other rubber components, such as natural rubber (NR), styrene-butadiene copolymer rubber (SBF), polybutadiene rubber (BR), acrylonitrile butadiene (NBR), polyisoprene, may be added in amounts within a range that does not impair these properties. (IR), chloroprene rubber (CR), butyl rubber (
IIR) and other resin components, such as polyethylene (PE
), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), etc. are also included. in this case,
The content of other rubber components is usually less than or equal to the amount of ethylene-propylene terpolymer or ethylene-propylene polymer.

In addition, the rubber compound forming the weatherstrip contains compounds commonly used for the above rubbers, such as sulfur, morpholine, disulfide, dicumyl peroxide, etc. as a vulcanizing agent, and 2- Mercaptobenzothiazole, zinc dimethyl-dithiocarbamate,
Tetramethylthiuram disulfide, anti-aging agent, antioxidant, ozone deterioration inhibitor such as phenyl-α-naphthylamine, 2,6-di-t-butyl-p-cresol, etc., filler such as carbon, hydrated silicic acid, magnesium carbonate. Needless to say, dioctyl sebacate, mineral oil and the like are used as plasticizers such as clay.

However, it goes without saying that other polymers for improving adhesion are not blended into the rubber compound according to the present invention.

Further, the urethane paint used in the present invention is, for example, one in which a pigment is mixed with a urethane polymer.

Examples of the above urethane polymer include a one-component urethane polymer obtained by subjecting a urethane prepolymer produced from a bifunctional polyol and a diisocyanate to a chain extension reaction with a low-molecular diol, or a one-component urethane polymer produced from a 2- to 4-functional polyol and a diisocyanate. A two-component urethane polymer obtained by mixing a di- to tetra-functional polyol with a urethane prepolymer produced by the above method immediately before use is mentioned.

Therefore, when manufacturing the automotive weather strip of the present invention, toluene is added to the surface of the vulcanized rubber to be coated by molding using a conventional molding method such as extrusion, compression molding, or injection molding. .1-A polyolefin diluted to a concentration of about 3% with a solvent such as trichloroethane is applied as a primer by dipping, brushing, or spraying, and after this has dried, the colored urethane paint is applied to the surface. , to form a coating layer.

(Function) As described above, the automobile weatherstrip whose surface is coated with colored urethane paint retains wear resistance and anti-freezing performance at low temperatures, and has sufficient functionality as a weatherstrip itself, just like conventional black urethane paint. In addition to fulfilling the
You can freely select the exterior and interior colors of your choice.
Particularly when matched with the interior color, it makes the interior of the hardtop car feel more expansive, making it easier to respond to diversifying market needs, and improving the exterior appearance.

(Example) The present invention will be further explained in detail below.

As described above, the present invention is a weather strip in which the surface is coated with a colored urethane paint via a primer, and this will be described in more detail according to a specific manufacturing method, and comparative examples will also be presented.

Example-1 100 parts of EPDM, 50 parts of carbon black, 40 parts of paraffin softener, 20 parts of calcium carbonate, 5 parts of zinc white
1 part of stearic acid, 2 parts of a vulcanization accelerator, and 1 part of sulfur. A rubber composition is heated and vulcanized in an oven at 200°C for 3 minutes to form an automotive weather strip using the vulcanizate as a base material. A polyolefin primer diluted with toluene to a concentration of 3% was applied to the surface, and after drying at room temperature for 10 minutes or more, a colored polyester polyol primer obtained by reacting with diisocyanate was applied.
The product was heated and dried at 0° C. for 15 minutes to obtain a colored urethane film weatherstrip product (A).

Comparative Example-1 100 parts of EPDM, 50 parts of carbon black, 40 parts of paraffin softener, 20 parts of calcium carbonate, 5 parts of zinc white
A rubber composition containing 1 part of stearic acid, 2 parts of vulcanization accelerator, and 1 part of sulfur was heated and vulcanized in an oven at 200° C. for 3 minutes to obtain a weatherstrip product (B).

Comparative Example-2 100 parts of EPDM, 50 parts of carbon black, 40 parts of paraffin softener, 20 parts of calcium carbonate, 5 parts of zinc white
1 part of stearic acid, 2 parts of vulcanization accelerator, and 1 part of sulfur were heated and vulcanized in an oven at 200°C for 3 minutes. A coating composition containing 100 parts of the prepared prepolymer, 5 parts of carbon black, and 100 parts of toluene was applied and dried by heating at 100° C. for 15 minutes to obtain a urethane film weatherstrip product (C).

Next, the above Weatherstrip products (A) and (B)
When we attempted physical property tests for (C),
The results shown in the table below were obtained.

However, the abrasion resistance test was based on the following test conditions.

Friction element: Glass (thickness: 51 m) Friction element cycle: 60 times/min Friction element stroke: 70 cranes In addition, the adhesion test was performed using a peel test (JIS DO202), and the followability test was performed using a bending test (JIS K 6301).
According to

From the results on the ridges, it can be seen that the weather strip of the present invention has the abrasion resistance of the urethane paint and has no inferiority in function as a weather strip.

(Effects of the Invention) In the present invention, the following effects can be achieved by coating the surface of the vulcanizate with the colored urethane paint as described above via a primer.

(1) Since the urethane paint on the surface of the weather strip is colored, it is possible to freely select the desired color, whether it is for the exterior or interior. In top-of-the-line cars, it gives off a sense of spaciousness inside the car, eliminating the sense of discomfort associated with the conventional color black.

(2) Since weather-resistant urethane paint is used, it has excellent durability and does not fade or change color.

(3) The colored urethane paint can be freely selected from either a glossy finish or a satin finish, which significantly improves the appearance.

(4) Colored urethane paint, like black urethane paint, has excellent abrasion resistance and anti-freezing properties at low temperatures, and provides sufficient functionality for the weather strip itself.

maintain.

Claims (1)

[Claims] 1. A urethane paint made of a vulcanized product of an ethylene-propylene rubber compound that is not blended with other polymers to improve adhesion, and a urethane paint mixed with a pigment to give it a color other than black is applied to the surface of the vulcanized product through a primer. A weather strip for automobiles characterized by forming a coating.