JPS6032582B2 - Automotive weather strip - Google Patents

Description

[Detailed description of the invention] TECHNICAL FIELD This invention relates to automotive weatherstrips.

Natural rubber, chloroprene rubber, styrene-butadiene copolymer rubber, etc. are used as materials for weather strips, but in addition to the functions of the weather strip itself, automotive weather strips also have soundproofing and stiffness resistance. A wide range of performance is required, including durability and abrasion resistance. Until now,
Chloroprene rubber coated urethane paints and silicon coatings have been explored as means to improve the abrasion resistance of the weatherstrip surface, but forming a chloroprene rubber coat is difficult in continuous molding and is expensive. can be,
Furthermore, since silicone coatings have poor abrasion resistance compared to film resistance, urethane paints have been used as a relatively good solution for improving abrasion resistance (silicon coatings and urethane coatings (See Table 2 at the end for each product used). On the other hand, in recent years, ethylene-propylene terpolymer (EPDM) and ethylene-propylene polymer (EPR), which are ethylene-propylene rubbers, have improved weather resistance, aging resistance, ozone resistance, etc. compared to conventional synthetic rubber, and have been used in automobiles. However, ethylene-propylene rubber has poor surface abrasion resistance, and even when urethane paint is applied to improve its abrasion resistance, the urethane coating does not form properly. Due to the poor adhesion of ethylene-propylene rubber, it was impossible to achieve the intended purpose. Several processing methods have already been attempted to improve the problem of poor adhesion of ethylene-propylene rubber. For example 01
Polish the surface with a wire brush or sandpaper, etc.
{21 UV irradiation, '31 immersion in concentrated sulfuric acid,
{41 Treating with a solution of a mixture of organic monocarboxylic acid and phosphoric acid, treating with wind aldehydes, [6} Painting a mixture of chlorinated polypropylene and ethylenediamine, '7 Treating with iodinated isocyanate, '8
} Methods include oxidizing the surface by exposing it to ozone, treating it with an alkyl hypohalite, and treating it with an epoxy resin modified with a '10 polymerized fatty acid, an amine curing agent, and an organic solvent. However, these conventional processing methods tend to cause uneven polishing;
■ There is a hygiene problem due to the generation of dust, ■ It causes deterioration of the vulcanizate, ■ It is dangerous to handle the treatment agent, ■
There are drawbacks such as requiring a special treatment agent, ■ The treatment process is complicated, and ■ Equipment costs are high. The adhesion with the vulcanized rubber is improved.
It wasn't limited. In order to improve the wear resistance of the surface of automotive weatherstrips based on ethylene-propylene vulcanized rubber, the present inventors improved the adhesion between the ethylene-propylene vulcanized rubber and the applied urethane paint. After conducting research on primer compositions, we found that we could create a primer composition that would not impair the flexibility and flexibility that are the characteristics of hot-flow rubber, but would also have sufficient adhesion to the vulcanized rubber base material. I found it.

In the present invention, this primer composition is applied to the urethane paint coating of an automobile weather strip based on ethylene-propylene vulcanized rubber. That is, the present invention uses ethylene-propylene vulcanized rubber as a base material, coats it with polyhydroxypolybutadiene in which 98% or more of double bonds are hydrogenated, and coats it with urethane paint. The present invention provides an automobile weather strip characterized by the following. Hereinafter, the present invention will be explained in detail. The polyhydroxypolybutadiene in which 98% or more of double bonds are hydrogenated as used in the present invention is as described below.

First of all, what is polyhydroxypolybutadiene mentioned here?
One or more per molecule, preferably 1.8 to 5. It is a polybutadiene polymer having a hard hydroxyl group, and the average molecular weight is usually 500 to 50,000, preferably 100.
0 to 20,000, and the manufacturing method thereof is not specified, but various known methods can be employed. For example, in the polymerization of butadiene, hydrogen peroxide, cyclohexanone peroxide, methyl ethyl ketone peroxide, azobis-based compounds having functional groups such as 8'-azobis(a-cyano)-n-propanol, 6,6-azopis(8- Radical polymerization may be carried out in a catalyst such as alcohol, ketone, or ester using a radical polymerization initiator containing a hydroxyl group such as cyano)-n-bentanol, or radical polymerization of aliphatic azodicarboxylic acid or its ester, etc. There is also a method in which polyhydroxybutadiene is obtained by polymerizing with an initiator and then reducing the carpoxyl group or ester moiety.

Further, anionic polymerization is carried out using an alkali metal such as sodium or lithium or a ring body of an alkali metal and a polycyclic aromatic compound as a catalyst, followed by alkylene oxide and EPIC.

A method of functionalizing with ruhydrin or the like may also be used. Specifically, the catalyst used for anionic polymerization is a lithium body such as naphthalene body, anthracene body, or biphenyl body, or 1,4-dialkali metal butane, 1,
Examples include dialkali metal hydrocarbons such as 5-dialkali metal pentane, 1,10-dialkali metal decane, 1,4-dialkali metal, and 1,1,4,4-tetraphenylbutane. Furthermore, in order to smoothly proceed with such anionic polymerization, a hydrocarbon solvent such as hexane, heptane, benzene, toluene, xylene, cyclohexane, etc. is used.

However, when an alkali metal is used as a catalyst, it is preferable to use the above solvent together with a Lewis base such as diethyl ether, dipropyl ether, ethylpropyl ether, ethyl butyl ether. Polyhydroxybutadiene can be obtained by reacting the thus obtained Ping polymer with an epoxy compound according to a conventional method, and then treating it with a brotonic acid such as hydrochloric acid, sulfuric acid, or acetic acid.

Epoxy compounds used here include ethylene oxide, propylene oxide, butylene oxide,
Monoepoxy compounds such as cyclohexene oxide, styrene oxide, phenylglycidyl ether, etc.: glycidyl ether of pisphenol A, vinylcyclohexene diepoxide, butadiene diepoxide, dicyclobentadiene diepoxide, limonene diepoxide, bisepoxide of ethylene glycol Polyepoxy compounds such as: haloepoxy compounds such as epichlorohydrin, epibromohydrin, methylepichlorohydrin, etc. can be used.

More preferred are polyepoxy compounds and haloepoxy compounds. In the case of a monoepoxy compound, the amount used is preferably an equimolar ratio, particularly 2 or more molar ratio, to the polymer.

At this time, it is thought that the epoxy compound is bonded to both ends of the living polymer in a ring-related manner, and the hydrogen atoms of the ring-opened hydroxy groups are bonded in a state where they are substituted with an alkali metal. On the other hand, when a polyepoxy compound or a haloepoxy compound is used, the purpose of the resulting polymer is determined. Depending on the molecular weight of the mer and the number of hydroxyl groups,
Although it is selected as appropriate, it is usually 0.5 for the living polymer.
~2.0 molar ratio is used, preferably 0.6-1.0 molar ratio.

At this time, after the epoxy is ring-opened, living polymers are mainly bonded to each other, and a polymer in which several molecules are bonded via an epoxy compound having a hydroxyl group substituted with an alkali metal is obtained.

Polyhydroxypolybutadiene can also be obtained by reducing a high molecular weight polybutadiene polymer obtained by ozonolysis or other methods and containing oxygen. Regarding the microstructure of the obtained polyhydroxypolybutadiene, depending on the manufacturing method, 1,
Polymers having varying proportions of 2-bonds and 1,4-bonds are obtained. For example, the microstructure of polyhydroxypolybutadiene produced using radical polymerization is cis-1
,4 bonds 6-30%, trans-1,4 bonds 50-50%
80%, 1,2 bonds account for 15-30%, usually 1,4
This results in a microstructure with many bonds. Furthermore, in the anionic polymerization method, polyhydroxypolybutadiene having a large number of 1,4-bonds can be obtained by selecting the type of catalyst and solvent used. In the present invention, the polyhydroxypolybutadiene in which 98% or more of the double bonds are hydrogenated is the polyhydroxypolybutadiene produced in this way, with the main chain and/or side chain being Obtained by hydrogenating heavy bonds. Hydrogenation catalysts include nickel, cobalt, chromium, copper, palladium, platinum, rhodium, osmium, ruthenium,
Rhenium and the like are generally used, but nickel and ruthenium are preferred. These various metal catalysts are used as the metal itself, as a heterogeneous catalyst supported on a carrier, or as a homogeneous catalyst in which the metal is a soluble salt. As the above-mentioned carrier, carbon, alumina, silica, alumina/silica, diatomite, barium carbonate, calcium carbonate, etc. are used.

The amount of the metal supported on this tin-coated carrier is usually 0.01 to 5.
% by weight, preferably from 0.2 to 15% by weight. Although polyhydroxypolybutadiene can be reacted as it is with hydrogen using the above-mentioned metal as a catalyst, a better hydrogenation reaction can be carried out by using a molten metal. As this solvent, aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, fables, or mixed solvents thereof can be used. The amount of the above-mentioned catalyst used during hydrogenation varies depending on the type of catalyst, hydrogenation method, etc., but for example, when carrying out suspension polymerization using a ruthenium catalyst, the ratio of ruthenium to polyhydroxypolybutadiene is is used in a range of 0.01 to 1.0% by weight.

The reaction temperature is preferably 20 to 150 qo. If the reaction temperature becomes high, the hydrogenation rate can be increased, but this is not preferable because the cleavage of hydroxyl groups becomes non-negligible. The hydrogen used may be used at normal pressure, in a flow system or at high pressure, and the hydrogenation reaction may be carried out in any reaction form such as a fixed bed suspension system. Under the above-mentioned hydrogenation conditions, the double bonds in the main chain and/or side chains in polyhydroxypolybutadiene are hydrogenated, but in the composition of the present invention, the double bonds in the polymer It is necessary that the polymer is almost completely hydrogenated, with 98% of the double bonds in the polymer before hydrogenation.
% or more, preferably 99% or more, more preferably until substantially no double bonds remain.

In the present invention, as a primer, polyhydroxypolybutadiene in which 98% or more of the double bonds have been hydrogenated is heated and melted on an ethylene-propylene vulcanized rubber base material, or it is dissolved in an organic solvent. Apply.

Examples of organic solvents in this case include hydrocarbons such as n-hexane, cyclohexane, benzene, toluene, and xylene; chlorine compounds such as chloroform, carbon tetrachloride, and trichlorethylene; Examples include carbon disulfide, and these can be used alone or in a mixture of two or more. The urethane paint used in the present invention is, for example, a mixture of urethane polymer, silicon oxide, carbon black, silicon, etc., and a solvent.

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 weight 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.

In addition to ethylene-propylene terpolymer or ethylene-propylene polymer, the ethylene-propylene vulcanized rubber used in the automotive weather strip of the present invention may contain other materials in an amount within a range that does not lose these properties. Rubber components, such as natural rubber (NR), styrene-butadiene copolymer rubber (SBR), polybutadiene rubber (BR), acrylonitrile butadiene (NBR), polyisoprene (IR), chloroprene rubber (CR), butyl rubber (1)
1R), and other resin components such as polyethylene (PE)
, polypropylene (PP), ethylene-vinyl acetate copolymer (
EVA) and the like are also included.

In this case, the content of other rubber components is usually 1/2 or less of the ethylene-propylene terpolymer or ethylene-propylene polymer. This vulcanized rubber also contains commonly used compounds, such as sulfur, morpholine, disulfide, dicumyl peroxide as a vulcanizing agent, and 2-mercaptobenzothiazo as a vulcanization accelerator.
phenyl-Q naphthylamine as an antiaging agent, antioxidant, and ozone deterioration inhibitor, such as zinc dimethyl dithiocarbamate, and tetramethylthiuram disulfide.
Needless to say, 2,6-di-t-butyl-p-cresol, etc., carbon, hydrated silicic acid, magnesium carbonate, clay, etc. are used as fillers, and dioctyl sebacate, mineral oil, etc. are used as plasticizers.

In addition, as foaming agents for rubber, N,N'-dinitroso bentamethylene tetramine, N,N'-dimethyl-N,
N'-dinitrosoterephthalamide, azodicarbonamide, azobisisobutyronitrile, benzene sulfonyl hydrazide, P,P'-oxybis(benzenesulfonyl hydraside, toluenesulfonyl hydrazide)
As foaming aids, urea, salicylic acid, etc. may be optionally blended depending on the amount of foaming.

Moreover, the presence or absence of foaming is arbitrarily adjusted depending on the application location. To manufacture the automotive weather strip of the present invention,
The above-mentioned primer is applied by spraying, brushing, or other painting methods to the sealing side of the ethylene-propylene vulcanized rubber, which has been molded by conventional extrusion, compression, or injection molding. After drying at a temperature ranging from room temperature to about 20,000 ℃, this is coated with a urethane paint by a normal coating method to form a urethane coating layer, and dried and cured.

In addition, on top of this automotive weather strip, in order to improve wear resistance and prevent blocking properties,
Furthermore, silicone may be applied. The automotive weather strip of the present invention has excellent adhesion between the ethylene-propylene diluted rubber and the urethane coating layer through a special brimer, so it has much better abrasion resistance than conventional products. It becomes something.

Examples of the present invention are listed below.

The results of physical property tests of the weather strips for personal vehicles obtained in Examples 1 to 5 and Control Examples 1 to 9 are listed in the table below.
In addition, the physical property test is based on the following.

○｝ Abrasion resistance test using a glass edge abrasion tester that is an improved version of the Gakushin abrasion tester.

Test conditions Friction element Glass (5 ribs thick) Friction element cycle 6 sub/min friction element stroke 7 Broadside Test method Normal wear:
Attach the sample to the above testing machine, rub the sample, and examine the abrasion properties under normal conditions.

Weather and abrasion resistance: Weather and abrasion resistance is examined by exposing the material to a weatherometer using two carbon arc lamps for 20 beats and then rubbing it.

[21 Adhesion test by peeling test (JISD0202) {3' Followability test example by bending test (JISK6301) 1 Ethylene loop.

Pyreneuter polymer-10 parts, carbon black 57
．． 5 parts, mineral oil 35 parts, zinc lotus 5 parts, stearic acid 1 part
1 part of rubber compound, 2 parts of vulcanization accelerator, 1.5 parts of sulfur.
Vulcanization was carried out at 60° C. for 30 minutes to prepare an ethylene-propylene terpolymer vulcanizate. 100% polyhydroxypolybutadiene with hydrogenated double bonds of 98% or more
After heating the mixture to a temperature of 100° C. and dipping the vulcanizate thereon, a urethane paint was applied thereto, and the mixture was dried and cured at 10,000°C for three intervals to produce a weather strip for an automobile.

Example 2 The same polyhydroxypolybutadiene as in Example 1 was dissolved in 9 parts of cyclohexanone, applied to the fluidized product used in Example 1, and the above solvent was evaporated at room temperature. After that, apply urethane paint to the surface and apply 16000
A weather strip for an automobile was manufactured by drying and curing for 0 minutes.

Example 3 5 parts of the same polyhydroxypolybutadiene as in Example 1 was added to n
- Dissolved in 95 parts of hexane and applied it to the same vulcanizate as in Example 1. After evaporating the solvent at room temperature, a urethane paint was applied and dried and cured at 90°C for 8 minutes to produce a weather strip for an automobile. .

Example 4 Same polyhydride as Example 1.

Dissolve 5 parts of xypolybutadiene in 95 parts of toluene, apply it to the same vulcanizate as in Example 1, evaporate the solvent at room temperature, apply urethane paint, dry and cure at 90o0 for 8 minutes, and apply it to the vulcanizate. manufactured weather strips for Example 5 6 parts of the same polyhydroxybutadiene as in Example 1 was dissolved in 95 parts of tetrahydrofuran, and then dissolved in Example 1.
After coating the same vulcanizate as above and evaporating the solvent at room temperature, a urethane paint was applied and dried and cured at 90oC for 8 minutes to produce weather strips for automobiles.

Comparative Example 1 Example 1 was carried out using a solution of Ester Resin 20J (trade name: Toyobo Aya Co., Ltd., saturated polyester) in a [methyl ethyl ketone [1]: toluene '9'] mixed solvent.
After drying at room temperature, a urethane paint was coated on the same vulcanizate as used in the above, and the urethane paint was heated and dried at 9000 for 8 minutes to produce a weather strip for automobiles.

Control example 2 "Vinyrite VMCH" (trade name: manufactured by Union Carbide, vinyl chloride-vinyl acetate copolymer resin) was dissolved in a mixed solvent of [methyl ethyl ketone [1]: toluene '1]]. Apply to the same vulcanizate as used in Example 1, dry at room temperature, then apply urethane paint to 90q.
A weather strip for automobiles was produced by heating and drying for 8 minutes at 1000 yen.

Comparative Example 3 A mixture of "Essurek BM-2" (trade name: Sekisui Chemical Co., Ltd., butyral resin) dissolved in a mixed solution of [butanol [1': xylene {1}], and the same as that used in Example 1 was used. The same vulcanizate was coated, and after drying at room temperature, a urethane paint was applied and dried and cured at 90° C. for 8 minutes to produce a weather strip for an automobile.

Control example 4 "Orestar M55-80A" (trade name: manufactured by Mitsui Tosho, moisture-curing polyurethane resin) dissolved in toluene was applied to the same additive as used in Example 1, and kept at room temperature. After drying, apply urethane paint 9
A weather strip for an automobile was manufactured by drying and curing for 8 minutes at 0:00.

Control example 5 10 anchors of “Desmophen 100” (trade name: manufactured by Bayer AG, polyhydroxy compound) and “Desmodur L” (
The same vulcanization as that used in Example 1 was carried out using a mixed solution of [Product name: Bayer, Polyisocyanate] 15 Ikarito in a mixed solution of [methyl glycol acetate: butyl acetate: ethyl acetate: toluene]. After applying it to an object and drying it at room temperature, a urethane paint was applied, and it was dried and cured for 8 minutes at 9 pips to produce a weather strip for an automobile.

Control example 6 "Betsukosol J-534" (trade name: manufactured by Dainippon Ink and Chemicals, linseed oil-modified long oil alkyd resin) was dissolved in a mineral base, and cobalt naphthenate was added as a desiccant. was applied to the same vulcanizate as used in Example 1, and after drying at room temperature, a urethane paint was applied and dried and cured at 90 oo for 8 minutes to produce a weather strip for an automobile.

Control example 7 "Beccosol J-524" (trade name: manufactured by Dainippon Ink and Chemicals, linseed oil modified short oil alkyd resin) 8 eaves, "
A mixture of 20 parts of Super Betsukamine J-820J (trade name: Dainippon Ink & Chemicals, butylated melanin resin) mixed and dissolved in xylene was used, and this was applied to the same vulcanizate used in Example 1. After drying at 12,000 for 30 minutes, a urethane paint was applied and dried and cured at 90 qo for 8 minutes to produce an automobile weather strip.

Control Example 8 A mixture of 99 parts of "Acryloid C-110V" (trade name: manufactured by Rohm and Haas, thermoplastic acrylic resin) and 1 part of nitrocellulose dissolved in toluene was used in Example 1. Apply it to the same vulcanizate that was used,
After drying at room temperature, a urethane paint was applied and dried and cured at 90 oo for 8 minutes to produce a weather strip for an automobile.

Control example 9 "Acrydic 47-712" (product name: Dainippon Ink & Chemicals, thermosetting acrylic resin) 8 anchors and "Super Beckamine 47-508" (product name: Dainippon Ink & Chemicals, butyl) Melamine resin) 2 Ikarito dissolved in a mixed solvent of [toluene {2) and butyl acetate [11] was used, and this was applied to the same vulcanizate as used in Example 1, and heated at 15,000 for 30 minutes. After drying, a urethane paint was applied and dried and cured at 9000 for 8 minutes to produce a weather strip for an automobile.

The results of the physical property tests for the above Examples and Control Examples are shown in Table 1 below.

As is clear from Table 1, the automotive weather strip of the present invention has extremely excellent adhesion between the tempered rubber base material and the urethane coating layer, and has better abrasion resistance, deformation followability, and adhesion than conventional products. It can be seen that it is significantly superior.

Table 2 shows the abrasion resistance of conventional silicone treatment and the use of urethane paint alone for comparison. Table 1) *1: Adhesiveness is observed, but it peels off with very little force, so it cannot be measured in the peeling test according to JISD0202.

*2: Adhesion itself is extremely poor and cannot be subjected to the Hakufuji test.

*3: Motomura was not exposed after more than 50,000 times of friction in the wear resistance test.

(Normal wear) *4: The base material is removed according to the number of times listed.

All control examples 1 to 9 agree.

Table 2 Wear resistance test results (Details) All numbers are based on the number of times of friction and base material exposure.

Claims (1)

[Claims] 1. It is characterized by having an ethylene-propylene vulcanized rubber as a base material, coated with polyhydroxypolybutadiene in which 98% or more of double bonds are hydrogenated as a primer, and covering the primer with urethane paint. Automotive weather strip.