KR100419849B1 - Expanded material for wiper blade and preparation method of thereof - Google Patents

Abstract

The present invention relates to a foamed molded article for wiper blades and a method for manufacturing the same, and more particularly, an ethylene-based polymer alone or a suitable amount of rubber is used as a base material, and a certain amount of a crosslinking agent, a foaming agent, a silane additive and other additives is added thereto. The present invention relates to a foamed molded article for a wiper blade, which is excellent in environmental aging resistance and abrasion resistance as compared with the prior art, and a method of manufacturing the same.

Description

Foamed article for wiper blades and manufacturing method thereof

The present invention relates to a foamed molded article for wiper blades and a method for manufacturing the same, and more particularly, an ethylene-based polymer alone or a suitable amount of rubber is blended, and a predetermined amount of a crosslinking agent, a foaming agent, a silane-based additive and other additives is added thereto to form a foamed molded article. The present invention relates to a foamed molded article for wiper blades superior in aging resistance and abrasion resistance as compared with the prior art, and a manufacturing method thereof.

Wiper blades are mainly used to clean windshields of wet or wet cars, tanks, aircraft, ships, etc.

Since the rubber products used in such wiper blades are always exposed to sunlight or weather, excellent environmental aging resistance, weather resistance and ozone resistance are required.

Conventional wiper blades are made of natural rubber (NR), butadiene rubber (BR), styrene-butadiene rubber (SBR) or other special rubbers, or ethylene-propylene rubber (EPDM) or chloroprene rubber (CR). ) And recently used silicone rubber or fluorine rubber.

However, in the case of using general rubber such as natural rubber, butadiene rubber, styrene-butadiene rubber or ethylene-propylene rubber (EPDM) or chloroprene rubber (CR) as the special rubber among the rubber types, the coefficient of friction of the rubber itself Because of the high wiper shake phenomenon was apt to occur.

In addition, when natural rubber, butadiene rubber, and styrene-butadiene rubber except ethylene-propylene rubber are used, since these rubbers essentially contain double bonds in their molecular structure, they are environmentally aging resistance (heat aging resistance, weather resistance, ozone resistance). ) Has the disadvantage of falling.

In addition, the friction coefficient can be reduced when using silicone rubber, fluorine rubber or fluorine resin, but in case of silicone rubber, it is difficult to reach satisfactory environmental aging resistance, and when using fluorine resin or fluorine rubber, raw rubber or resin is expensive. In addition to the workability was inferior in moldability.

Accordingly, the present inventors foamed by containing an appropriate amount of ethylene-based polymer and rubber in order to produce a wiper to improve the environmental aging resistance, which is a problem of the conventional wiper blade rubber, and excellent moldability, while maintaining a proper friction characteristics with the glass surface This invention was completed by manufacturing a molded object.

Accordingly, an object of the present invention is to provide a foamed molded article for a wiper blade excellent in wear resistance and environmental aging resistance and a method of manufacturing the same.

The present invention is based on a substrate consisting of 75 to 100 parts by weight of ethylene polymer and 0 to 25 parts by weight of rubber, 0.05 to 10 parts by weight of blowing agent, 0.1 to 4 parts by weight of crosslinking agent, silane coupling agent, silicone oil and It is characterized by the foamed molded article for wiper blades containing 0.01-10 weight part of silane additives selected from silicone rubber.

In the method for producing a foamed molded article for a wiper blade, the substrate, the foaming agent, the crosslinking agent, the silane additive and the additive are mixed in a mixer at a temperature of 80 to 120 ° C. and sufficiently kneaded, and then the mixture is 140 to 200 ° C. and 100 to 150. Another feature is a method for producing a foamed molded article for wiper blades obtained by molding into a foam at kg / cm ² .

Referring to the present invention in more detail as follows.

The present invention relates to a foamed molded article for improved wiper blades which is excellent in environmental aging resistance and free from stick-slip phenomena occurring in general wiper blades.

In the present invention, the substrate is preferably used by mixing 75 to 100 parts by weight and 0 to 25 parts by weight of an ethylene polymer and rubber, respectively. The present invention uses an ethylene-based polymer as a base material to lower the friction coefficient compared to the conventional rubber wiper blades to prevent the wiping of the wiper blades, and to improve the moldability and environmental aging resistance.

As the ethylene polymer, polyethylene (PE), ethylene vinyl acetate copolymer (EVA), or ethylene alpha olefin copolymer may be used. If the content is less than 75 parts by weight, the hardness of the prepared foam is low and thus as a wiper blade. Poor performance

The rubber may be used alone or mixed with styrene-butadiene rubber, natural rubber, isoprene rubber, butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, or acrylonitrile-butadiene, and if the content When it exceeds 25 weight part, moldability and environmental aging resistance will fall.

In the present invention, it is preferable to contain a foaming agent that expands to the most important additive to lower specific gravity, and contains 0.05 to 10 parts by weight with respect to 100 parts by weight of the base component, and if the content is less than 0.05 parts by weight, the hardness of the foamed molded article for the wiper blade and If the specific gravity is high and exceeds 10 parts by weight, a foam having a uniform bubble cannot be obtained due to a sudden expansion beyond the high temperature viscoelastic limit of the resin. The blowing agent may be selected from azo compounds, nitroso compounds, and sulfonylhydrazide compounds having a decomposition temperature of 130 to 200 ° C., and may be used singly or in combination of two or more thereof. When the compound used as the blowing agent is described in more detail, azo-dicarbonamide, azobisisobutyronitrile or diazoaminoazobenzene may be used as the azo-based compound, and N, N'-dinitro is used as the nitroso-based compound. As a pentamethylene tetraamine and a sulfonyl hydrazide type compound, p-toluenesulfonyl hydrazide, p, p'- oxybis (benzenesulfonyl hydrazide), benzenesulfonyl hydrazide, etc. can be used.

In order to provide high temperature viscoelasticity suitable for foaming in the present invention, the organic peroxide crosslinking agent is preferably contained in an amount of 0.1 to 4 parts by weight based on 100 parts by weight of the substrate. If the high temperature viscoelasticity is not maintained, and exceeds 4 parts by weight, the hardness is sharply increased and the foam becomes unstable. The crosslinking agent is t-butyl peroxy isopropyl carbonate, t-butyl peroxy laurate, benzoyl peroxide, t-butyl peroxy acetate, t-butyl peroxy benzoate, di-t-butyl diperoxy phthalate , t-butylperoxy maleic acid, cyclohexanone peroxide, t-butyl cumyl peroxide, t-butyl hydroperoxide, 1,1-bis (t-butylperoxy) -3,3,5-srimethylcyclohexane , t-butylperoxybenzoate, dicumyl peroxide, 2,2-bis (t-butylperoxy) butane, 1,1-di (t-butylperoxy) cyclohexane, methylethylketone peroxide, 2, 5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5- (t-butylperoxy) hexyn-3, 2,5-dimethyl-2,5-di (Benzoylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexine-3, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane-3, di-t -Butyl peroxide, n-butyl-4,4-bis (t-butylperoxy) valerate and 2,2'-bis (t-butylperoxyisopropyl) benzene You can use the selected one.

In the present invention, the silane coupling agent selected from the silane coupling agent and the silicone oil and the silicone rubber used for improving the frictional properties and the wear resistance of the foamed molded article for the wiper blade is preferably contained in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the substrate. If the content is less than 0.01 part by weight, no improvement in frictional properties can be expected. If the content exceeds 10 parts by weight, there is almost no improvement in physical properties due to the increase. Examples of the silane coupling agent include vinyl silanes such as vinyl trichlorosilane, vinyl tri (2-methoxyethoxy) silane, vinyl triethoxy silane and vinyl trimethoxy silane, and 3-methacryloxypropyl trimethoxy. Silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N 2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3 -Chloropropyltrimethoxysilane and the like, and those treated with an inert carrier such as calcium carbonate can be used.

In addition, the foamed molded article for the wiper blade of the present invention may be added to the metal oxide, fatty acids, fillers, foaming aids, crosslinking aids, stabilizers, abrasion resistance improvers and additives for reducing the coefficient of friction as needed.

Among the additives, fillers that act as nucleating agents in the present invention are selected from hard and heavy calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, silica, clay, talc, carbon black and modified substances thereof in 100 parts by weight of the substrate. It can contain 0-10 weight part with respect to.

In addition, the present invention may contain 1 to 5 parts by weight of a metal oxide or a crosslinking aid (internal mold release agent) in 100 parts by weight of the base material in order to improve processing characteristics and to improve physical properties of the foam. The metal oxide may be cadmium oxide, zinc oxide, magnesium oxide, mercury oxide, tin oxide, lead oxide, calcium oxide, and the like. The crosslinking aid (internal mold release agent) may be stearic acid, zinc stearate, zinc carbonate, calcium carbonate, barium stearate. Etc. can be used. In particular, the metal oxide also serves as a decomposition aid for the blowing agent.

In the production of foamed molded articles for wiper blades, a banbury mixer and an open roll mill are opened at a temperature range of not less than the melting point of the ethylene-based polymer as the base material and not more than the decomposition point of the blowing agent and the crosslinking agent, that is, 80 to 120 ° C. After kneading with a roll mill or kneader to make a kneaded product, it is made into sheets for compression molding and pellets for injection molding. Then, the foam is formed by pressing and heating. It includes the manufacturing method of the foamed molded object for wiper blades which pressurizes for 5 to 60 minutes on the conditions of 100-150 kg / cm <^2> and shaping | molding pressure, and forms a foam by opening a metal mold | die.

In more detail, the manufacturing method is first prepared into a closed mold by producing a compound in which a foaming agent, a crosslinking agent and other additives, and a silane-based additive or other additives as necessary in the form of a sheet (sheet). At this time, in the case of compression molding, the press is used, and in the case of injection molding, the compound is introduced into the mold to maintain high temperature and pressure for 5 to 60 minutes to proceed with crosslinking and foaming, and then the mold is opened momentarily. By expanding the pressure using a pressure difference by removing the pressure, a foamed molded article for a wiper blade having a fine cell structure is produced.

In this case, the foam may be directly molded into a product shape, or it may be made into a product form through post-processing such as skiving or grinding by preparing a foam on a sheet. In addition, by using a skiving machine and a cutter (cutter) to make a certain thickness and size, after the trimming and grinding process of the skilled worker and put it back into a mold having a product form 120 ~ A hot press at 180 ° C. for 3 to 20 minutes and a cold press for 10 to 20 minutes at a low temperature of about 0 to 30 ° C. with the mold closed again to remove the product. It is also possible to produce a product in the desired form.

The foamed molded article for the wiper blade according to the present invention prepared by the above composition and method has a permanent compression ratio of 10 to 40%.

The foamed molded article for the wiper blade according to the present invention as described above is a wiper blade made of conventional solid rubber has a specific gravity of 1.0 to 1.4 range, compared to the specific gravity of 0.2 to 0.9 range of light weight and excellent foaming characteristics, there is no shaking phenomenon In addition, it is excellent in elasticity to prevent local wear of the glass by sand or dust attached to the glass when the normal rubber wiper is in operation. In addition, since the friction coefficient is smaller than the conventional one, the wear resistance is excellent and the environmental aging resistance is excellent because the double bond is not contained in the molecular structure.

In addition, the foamed molded article for the wiper blade according to the present invention is capable of producing a wiper blade of various colors, such as white, yellow, because the cross-linking by the organic peroxide in the molding of the foam has an advantage in terms of fashion.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by Examples.

Example 1

90 parts by weight of the ethylene-butene copolymer resin and 10 parts by weight of the ethylene-propylene diene rubber were used to obtain zinc oxide, stearic acid, titanium oxide, silicone oil, and other preparations in the temperature range of 80 to 120 ° C. After kneading and kneading, a dicumyl peroxide and an azodicarbonamide-based blowing agent were added thereto as a crosslinking agent, and kneaded for about 20 minutes to prepare a sheet-like kneaded product. This was put into a mold having a thickness of 20 mm under conditions of 150 ° C. and 150 kg / cm ² , and pressed for 40 minutes to demould to form a foam for wiper blades.

Example 2

Using a blend of 30 parts by weight of ethylene-octene copolymer, 50 parts by weight of ethylene vinyl acetate copolymer and 20 parts by weight of isoprene rubber as the substrate, the composition shown in Table 1 above has a surface temperature of 90 to 105 ° C. Kneading in a roll mill was carried out, and in particular, 3 parts by weight of vinyl tri (2-methoxyethoxy) silane was kneaded together as a silane coupling agent, and then a foam for a wiper blade was formed by a press method.

Example 3

Based on the blend of 70 parts by weight of ethylene-butene copolymer and 30 parts by weight of ethylene vinyl acetate copolymer, a compound was prepared in the same manner as in Example 1, and the obtained compound was immediately pelleted, and the wiper blade was injected by injection molding. The foam for was molded. At this time, the injection temperature was 170 ℃ and the clamping time was 420 seconds in the screw temperature 80 ~ 110 ℃ range.

Example 4

The base material was a blend of 65 parts by weight of ethylene-butene copolymer, 30 parts by weight of ethylene vinyl acetate copolymer, and 5 parts by weight of ethylene-propylene-diene rubber. Other kneading methods and molding methods were performed in the same manner as in Example 3 for wiper blades. Foams were prepared.

Comparative example

Tridonwipe ^TM (AD), a commercially available product of a diene rubber wiper blade, was used as a comparative example.

Test Example

The physical properties of the molded article prepared in Examples 1 to 4 and the product of Comparative Example were measured by the following method, and the results are shown in Table 2 below.

<Test method>

1. Measurement of Friction Coefficient

The static friction coefficient was measured using a friction tester (slip tester) to measure the starting angle (θ) of the slip and then obtained tanθ as the friction coefficient.

The dynamic friction coefficient was calculated by dividing this value by the given load by measuring the slip resistance by using UTM. At this time, the friction surface was used as the glass surface, and the friction coefficient for the wet surface was measured by measuring the friction coefficient in the state of water sprayed on the glass surface.

2. Specific gravity

Specific gravity was measured five times using an automatic specific gravity measurement device and the average value was taken.

3. Hardness

Hardness was measured in accordance with ASTM D-2240 by cutting an intermediate portion of the foam with an Asker C type hardness meter.

4. Tensile Strength and Elongation

After making a test piece having a thickness of 3 mm from the foam, a test piece was made with a No. 2 mold knife, and tensile strength and elongation were measured according to KS M 6518. At this time, five test pieces were used for the same test, and the tensile speed was 500 mm / min.

5. Compression set

Permanent compression shrinkage was measured in accordance with ASTM D-3754 for a specimen prepared in the form of a cylinder having a diameter of 30 ± 0.5mm after the foam was prepared to a thickness of about 10mm. After the heat treatment was left for 6 hours in an air circulating oven maintained at 50 ± 0.1 ℃, the test pieces were taken out and left for 30 minutes (cooling) at room temperature, and the thickness was measured.

In Equation 1; t ₀ is the initial thickness of the test piece, t _f is the thickness after cooling and ts is the thickness of the space bar.

As shown in Table 2, it was confirmed that the foamed molded article of Examples 1 to 4 according to the present invention had excellent frictional properties, light weight and particularly excellent permanent compression yield, so that adhesion to the glass surface and wipe performance were increased. In addition, since Examples 1 to 4 of the present invention are foams, the tensile strength of 40 kg / cm ² or more is suitable for the wiper blade.

As described above, the foamed molded article for the wiper blade according to the present invention uses an ethylene-based polymer and rubber as a substrate, and uses a foam instead of a conventional solid rubber as a base material, thereby providing a wiper at weather resistance, abrasion resistance, in particular, semi-dry or cold. The phenomenon of adhesion between the blade rubber and the glass surface stops the operation of the wiper (so-called lock phenomenon), vibration caused by the speed dependence of the friction coefficient, poor effect of the wiper, abnormal friction of the blade surface, It solves problems such as shortening the life of the connection angle part of the wiper system and can be usefully used for the wiper blade.

Claims (8)

From 0.05 to 10 parts by weight of foaming agent, 0.1 to 4 parts by weight of crosslinking agent, silane coupling agent, silicone oil and silicone rubber with respect to a base material consisting of 75 to 100 parts by weight of an ethylene polymer and 0 to 25 parts by weight of rubber, and 100 parts by weight of the base material. A foamed molded article for wiper blades comprising 0.01 to 10 parts by weight of the selected silane additive. The foamed molded article for wiper blade according to claim 1, wherein the ethylene polymer is selected from polyethylene, ethylene vinyl acetate copolymer and ethylene alpha olefin copolymer. The rubber according to claim 1, wherein the rubber is one or more selected from styrene-butadiene rubber, natural rubber, isoprene rubber, butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, and acrylonitrile-butadiene rubber. Foamed molded article for wiper blades. The foamed molded article for wiper blade according to claim 1, wherein the blowing agent is one or a mixture of two or more selected from azo compounds, nitroso compounds, and sulfonylhydrazide compounds. The method of claim 4, wherein the azo compound is selected from azodicarbonamide, azobisisobutyronitrile and diazoaminoazobenzene, and the nitroso-based compound is N, N'-dinitrosopentamethylenetetraamine, The sulfonyl hydrazide-based compound is a foamed molded article for wiper blades, characterized in that selected from p-toluenesulfonylhydrazide, p, p'-oxybis (benzenesulfonylhydrazide) and benzenesulfonylhydrazide. The method of claim 1, wherein the crosslinking agent is t-butylperoxyisopropyl carbonate, t-butylperoxylaurylate, benzoyl peroxide, t-butylperoxy acetate, t-butylperoxybenzoate, di- t-butyldiperoxyphthalate, t-butylperoxymaleic acid, cyclohexanone peroxide, t-butyl cumyl peroxide, t-butyl hydroperoxide, 1,1-bis (t-butylperoxy) -3,3, 5-Srimethylcyclohexane, t-butylperoxybenzoate, dicumylperoxide, 2,2-bis (t-butylperoxy) butane, 1,1-di (t-butylperoxy) cyclohexane, methylethyl Ketone peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5- (t-butylperoxy) hexine-3,2,5-dimethyl -2,5-di (benzoylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexyn-3, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane -3, di-t-butylperoxide, n-butyl-4,4-bis (t-butylperoxy) valerate and 2,2'-bis (t-butylperoxy Foamed molded article for wiper blades, characterized in that selected from isopropyl) benzene The foamed molded article for wiper blade according to claim 1, wherein the foamed molded article for wiper blade has a permanent compression shrinkage of 10 to 40%. In the method for producing a foamed molded article for a wiper blade, a substrate, a crosslinking agent, a foaming agent, a silane additive and an additive are mixed in a mixer at a temperature of 80 to 120 ° C., and sufficiently kneaded, and then the mixture is 140 to 200 ° C. and 100 to 150 kg / cm. Method for producing a foamed molded article for wiper blades, characterized in that obtained by molding into a foam in ² .