KR101209604B1 - Composition of windshield wiper blade - Google Patents

Abstract

The present invention relates to a rubber composition for wiper blades, and more particularly, to a rubber mixture in which natural rubber (NR) and chloroprene rubber (CR) are mixed at an optimum ratio, a positively extruded carbon black and a high wear resistant carbon black mixture, a rubber softener, Sulfur crosslinking agent, crosslinking activator, Nt-butyl-2-benzothiazole sulfenamide, tetramethylthiuram disulfide and dithiodimorpholine in a specific ratio of a crosslinking accelerator, an antioxidant, and an ozone antiaging agent Compared to the conventional wiper blades, the wiper blade manufactured by mixing natural rubber alone or ethylene propylene diene rubber (EPDM) has improved its problems such as physical resistance, ozone resistance, heat resistance, and permanent deformation. It relates to a rubber composition for wiper blades that satisfies all the performance of the rubber material.

Wiper, Blade, Chloroprene, Ozone Resistant, Rubber, Automotive

Description

Rubber composition for wiper blades {Composition of windshield wiper blade}

1 shows the structure of a motor vehicle wiper according to the present invention.

The present invention relates to a rubber composition for wiper blades, and more particularly, to a rubber mixture in which natural rubber (NR) and chloroprene rubber (CR) are mixed at an optimum ratio, a positively extruded carbon black and a high wear resistant carbon black mixture, a rubber softener, Sulfur crosslinking agent, crosslinking activator, Nt-butyl-2-benzothiazole sulfenamide, tetramethylthiuram disulfide and dithiodimorpholine in a specific ratio of a crosslinking accelerator, an antioxidant, and an ozone antiaging agent Compared to the conventional wiper blades, the wiper blade manufactured by mixing natural rubber alone or ethylene propylene diene rubber (EPDM) has improved its problems such as physical resistance, ozone resistance, heat resistance, and permanent deformation. It relates to a rubber composition for wiper blades that satisfies all the performance of the rubber material.

The wiper system consists of a wiper blade assay, a wiper arm and a wiper motor drive. The wiper blade assay is again made up of wiper blade rubber and wiper blades.

The main function of the wiper is to remove all moisture (rain, snow, frost, etc.) on the front or rear of the vehicle, or to remove the dirt on the soiled glass to wipe out the washer fluid to ensure visibility while driving. Is an important part of safety and must be in optimum condition for wiper to function properly.

Factors that determine the performance of the wiper for securing this field of view are as follows.

The uniformity of the pressure distribution across the wiper blades as seen throughout the wiper system, the ability of the wiper blade rubber material to directly dry off the glass, and the strength of the wiper arm between the motor and the wiper blades These factors are factors such as the surface roughness of the glass surface being rubbed and the pressure generated by the air resistance generated during high-speed driving or the emergency of the wiper.

When these factors are not able to perform their original functions, the wiper system does not perform its original main function of wiping performance and causes problems such as deterioration of wiping performance or noise generated during operation.

Another important factor in the performance of the wiper is the driver's habit, which is not just removing water, but also when the wiper is operated to remove dust, or when the wiper button is turned on when it rains, the starter is turned on and then on a sunny day. If the friction occurs in a dry state, such as in operation, even the best wiper system will cause damage to the rubber and make it difficult to function properly.

Rubber for wiper blades is a rubber material that directly rubs against the glass on the front or rear of the vehicle and takes a load of about 15 g per cm and is an important contributor to the wiping blade's wiping performance. These features require high-performance materials that are flexible, low friction, noise-free, and have excellent wipe performance. Many experiments and studies have been conducted so far to have the most suitable rubber material and rubber compound.

Generally, the rubber material for automobile wiper blades currently on the market is mostly natural rubber (NR). This is due to the excellent mechanical properties of natural rubber itself (tensile strength, elongation, wear, elasticity, etc.) and low price competitiveness over other rubber materials. However, natural rubber has a disadvantage in that durability due to heat aging and ozone aging is somewhat weak due to the structural characteristics of having unsaturated double bonds in the main chain, and it is urgent to overcome the disadvantages of the blade of natural rubber material. ].

Japanese Patent Laid-Open No. 8-319375 discloses a wiper blade rubber in which carbon black is added to a mixture of natural rubber and chloroprene rubber. In addition, Korean Utility Model Publication No. 1988-0003346 shows carbon black, vulcanizing agents, fillers, etc. in natural rubber and chloroprene rubber mixtures, but the wiping and rubbing performance, heat resistance, permanent deformation and In view of the physical properties of materials such as stain resistance, the invention of the rubber composition for wiper blades having excellent durability is urgent as there is a limit in the composition of the natural rubber-chloroprene rubber mixture having optimum performance as a wiper blade.

Accordingly, the present inventors have made efforts to solve the above problems, carbon black, rubber softener, sulfur crosslinking agent, crosslinking activator, crosslinking accelerator, antioxidant, and ozone anti-aging agent as a rubber composition, the carbon black As a result, a mixture of positively extruded carbon black having an excellent extrusion performance of 40 to 48 nm and high abrasion resistant carbon black having an excellent wear performance of 26 to 30 nm is mixed and administered at an optimum ratio, and a crosslinking accelerator and an antioxidant are mixed in a specific ratio. Ingredients were used. This induces synergism with the oxidant which prevents oxidation by heat and light as it crosslinks, thereby preventing mechanical properties such as hardness and preventing aging of rubber compositions due to sunlight and excellent cleaning performance as a basic performance. The invention has been completed by developing a rubber composition for the wiper blades using the optimum ratio.

Therefore, the present invention maintains the mechanical properties such as hardness, tensile strength, elongation, and excellent wiping performance, rubber composition does not generate ozone reaction due to sunlight, applied to the wiper blades of automobiles, etc. It is an object to provide a rubber composition for a wiper blade that can be managed and does not occur.

The present invention is 100 parts by weight of a mixture of natural rubber and chloroprene rubber in a 60: 40 ~ 95: 5 weight ratio, carbon black having a particle diameter of 40 ~ 48 nm and carbon black having a particle diameter of 26 ~ 30 nm 35: 45 ~ 80 parts by weight of carbon black mixed in a 50:30 weight ratio, 3 to 5 parts by weight of rubber softener, 0.5 to 2.5 parts by weight of sulfur crosslinking agent, 6 to 7 parts by weight of crosslinking activator, Nt-butyl-2-benzothiazole sulfenamide and tetramethyl 2 to 3 parts by weight of crosslinking accelerator, 2-mercaptobenzoimidazole and 2,2`-methylene bis (4, in which thiuram disulfide and dithio morpholine are mixed in a 20:30:50 to 30:40:30 weight ratio -Methyl-6-t-butylphenol) is characterized in a rubber composition for wiper blades containing 2 to 4 parts by weight of antioxidant mixed in a weight ratio of 35:65 to 55:45 and 1.5 to 2.5 parts by weight of an ozone anti-oxidant.

Hereinafter, the present invention will be described in detail.

The present invention is a carbon black, a rubber softener, a crosslinking agent, a crosslinking agent, Nt-butyl-2-benzothiazole sulfenamide in which a positively extruded carbon black and a high wear resistant carbon black are mixed in a rubber mixture in which natural rubber and chloroprene rubber are mixed at an optimum ratio. In the rubber composition in which a crosslinking accelerator, an antioxidant, and an ozone aging agent are mixed with tetramethylthiuram disulfide, and dithio dimethyl morphine in an optimum ratio, the rubber mixture, carbon black, crosslinking accelerator, and antioxidant are particularly suitable for sunlight. The present invention relates to a wiper blade rubber composition which prevents ozone aging of the rubber composition and satisfies mechanical properties such as heat resistance and permanent deformation that the wiper blade should have.

Referring to each component of the rubber composition for wiper blades of the present invention in more detail as follows.

In the rubber mixture used in the present invention, natural rubber and chloroprene rubber have a similar basic structure except that they have a methyl group (-CH ₃ ) and a chlorine group (-Cl) in terms of chemical structure, so they are easily compatible with each other, and thus mixing is useful. Do. Although natural rubber is competitive in terms of mechanical properties (tensile strength, elongation, wear and elasticity) and price compared to other rubbers, natural rubber has the disadvantage of poor durability due to heat aging and ozone aging.

In order to overcome these disadvantages, the present invention may have high heat resistance by mixing chloroprene rubber having a high van der Waals bond with a chlorine group in the main chain to a natural rubber having a methyl group in the main chain. The rubber mixture is used in the mixing ratio of the natural rubber and chloroprene rubber in the weight ratio of 60: 40 ~ 95: 5 weight ratio and less than 60: 40 is good mechanical performance but suitable physical properties as a rubber material for the wiper blade in ozone resistance and heat resistance When not exceeding 95: 5, problems such as mechanical properties such as permanent deformation, which are important for wiping performance, occur.

The carbon black used in the present invention increases the affinity with rubber and reinforces the strength. The carbon black used in the present invention has a fast extruding furnace carbon black having a particle diameter of 40 to 48 nm and a particle size. This 26 ~ 30 nm high Abrasion Furnace carbon black is used in a mixture of 30: 70 ~ 60: 40 weight ratio, when the mixing ratio is less than 30: 70 will be limited by the increase in production speed through rapid extrusion , 60: Extrusion rate is faster than 40, but the problem of wear performance is lower than the above formulation. The reason why the positively extruded carbon black and the high wear resistant carbon black are mixed is to obtain a synergistic effect because there is no carbon black having both extrusion performance and abrasion performance.

The content of the carbon black is used in the range of 40 to 50 parts by weight based on 100 parts by weight of the rubber mixture, and the mechanical properties and the heat resistance thereof are lowered when the weight is less than 40 parts by weight. Problem occurs.

Rubber softener used in the present invention is to give plasticity to the rubber to aid in mixing or dispersing the compounding agent to improve the processability during extrusion or injection, and distinguishes it from the plasticizer in that it lowers the hardness itself rather than simply lowering the glass transition temperature. do. The content of the rubber softener is used in the range of 3 to 5 parts by weight with respect to 100 parts by weight of the rubber mixture, and less than 3 parts by weight of plasticity has a problem in that the workability is somewhat deteriorated, when it exceeds 5 parts by weight is too soft to have a hardness Falling problem occurs. As the rubber softener, it is more effective to use a paraffin softener or an aromatic oil that is a mineral oil softener.

Sulfur cross-linking agent used in the present invention serves to connect the chain rubber polymer to the three-dimensional network structure and the content of the cross-linking agent is used in the range of 0.5 to 2.5 parts by weight based on 100 parts by weight of the rubber mixture, less than 0.5 parts by weight Particularly uncrosslinked at the time is more likely to occur, the hardness is lowered, excessive crosslinking occurs when more than 2.5 parts by weight due to the difficulty of processing and the hardness increases the problem of inflexibility.

The crosslinking activator used in the present invention serves to further promote the accelerating reaction by activating the following crosslinking accelerator and the content is used in the range of 3 to 5 parts by weight based on 100 parts by weight of the rubber mixture, and the crosslinking reaction is less than 3 parts by weight. It takes a long time to have a disadvantage in that the production is slow, and when more than 5 parts by weight to promote the cross-linking reaction, the reaction is too fast may cause quality problems, such as the occurrence of defects due to pre-vulcanization. Therefore, it is more effective to use zinc oxide or stearic acid as the crosslinking activator.

The crosslinking accelerator used in the present invention is used to shorten the crosslinking time of the crosslinking agent, and the crosslinking accelerator may contain Nt-butyl-2-benzothiazole sulfenamide, tetramethylthiuram disulfide, and dithiodimorpholine, respectively. : 30: 50 ~ 30: 40: 30 It is used by mixing in the weight ratio and when less than 20: 30: 50 unvulcanized phenomenon occurs that will not cause sufficient crosslinking reaction within a given time, which will result in unsatisfactory physical properties. If it exceeds 40:30, the crosslinking reaction is speeded up, which causes a problem of pre-vulcanization, that is, scorch.

The amount of the crosslinking accelerator is used in an amount of 0.5 to 2 parts by weight based on 100 parts by weight of the rubber mixture.

The antioxidant used in the present invention is used to prevent oxidation due to aging of rubber, and 2-mercaptobenzimidazole and 2,2`-methylene bis (4-methyl-6-t-butylphenol) are respectively 40: It is used by mixing in 60 to 60:90 weight ratio, the amount used is in the range of 1 to 1.5 parts by weight with respect to 100 parts by weight of the rubber mixture, when less than 1 part by weight physical damage such as cracks by oxygen and ozone in the atmosphere This may occur, and if it exceeds 1.5 parts by weight, it will cause contamination.

The ozone anti-aging agent used in the present invention is used to prevent aging due to the reaction between the sun and rubber, and the amount of the anti-aging agent is used in the range of 2 to 3 parts by weight based on 100 parts by weight of the rubber mixture and is less than 2 parts by weight. Cracks due to crosslinked chain breakage due to ozone (O ₃ ) in the middle, and when exceeding 3 parts by weight also causes problems such as whitening and pollution. It is more effective to use N-isopropyl-N`-phenol-p-phenylenediamine which is excellent in fouling resistance and resistant to ozone as the ozone anti-aging agent.

In the present invention, a compatibilizer is not additionally used in addition to the natural rubber and the chloroprene rubber. Because the two rubbers have a similar basic structure except that they have a methyl group (-CH ₃ ) and a chlorine group (-Cl) because of their chemical structure, they can be easily blended with each other. In addition, the compatibilizer was not used because it is one of the factors causing the deterioration of the physical properties of the rubber material.

The manufacturing method of the rubber composition for wiper blades of this invention is a general method used at the time of manufacture in the art, and does not specifically limit the method.

A schematic manufacturing method is as follows.

First, filtering is performed to remove foreign substances from raw materials. After filtering, the final rubber compound is mixed through a roller to ensure that the compound is mixed evenly. The blended rubber is cut to a suitable size and then subjected to aging to vulcanization. In order to finish the rubber material for the wiper blade, the surface material is finally processed to manufacture the rubber material for the final wiper blade.

Hereinafter, the present invention will be described in more detail based on the following examples, but the present invention is not limited to the examples.

Example   1 to 3

Rubber kneading of natural rubber and chloroprene rubber, carbon black, rubber softener, crosslinking agent, crosslinking agent, crosslinking accelerator, antioxidant and ozone antiaging agent at 120-130 ° C. for 10-30 minutes as shown in Table 1 below. A rubber composition was prepared by mixing using a group.

Example 4

In the same manner as in Example 1, a rubber composition was prepared by additionally adding a compatibilizer.

Comparative Examples 1 to 2

To carry out the same as in Example 1, to prepare a composition with the composition shown in Table 1 below.

The physical properties of the compositions prepared in Examples 1 to 4 and Comparative Examples 1 and 2 are measured, and are shown in the following Tables 1 to 2.

Experimental Example

1. Hardness: measured using a hardness tester at room temperature.

2. Tensile strength: measured at room temperature using a dumbbell No. 3 test piece.

3. Elongation: measured at room temperature using a dumbbell No. 3 test piece.

4. Tensile stress (100% modulus): Measured using a dumbbell No. 3 specimen at room temperature.

5. Hardness change: The values before and after aging were measured using a race at 80 ℃.

6. Tensile strength change rate: It was measured after aging using a rubber tensioning machine at 80 ℃.

7. Elongation rate of change: It was measured after aging using an elongation measuring device of the rubber tension machine at 80 ℃.

8. Tensile stress change rate: It was measured after aging using a rubber tension machine at 80 ℃.

9. Ozone resistance: measured using an ozone generator at 40 ° C.

10. Volume change rate: Measured using methanol for 24 hours at room temperature.

11. Pollution resistance: measured using washer solution for 24 hours at 50 ℃.

12. Wiping performance: The window was sprayed with water under rain conditions, the wipers were operated, and the wipers were operated 20000 times. Class 1 means that there is no 1 mm thick line, class 2 is 1 to 2 lines, class 3 is 3 to 4 lines, class 4 is 5 to 6 lines, and class 5 is more than 7 lines.

According to the results of Table 2, compared to the rubber composition for wiper blades made of only natural rubber, the composition containing natural rubber and chloroprene rubber showed excellent tensile strength and elongation, and flexibility to influence wiping performance was also excellent. In addition, the compressive permanent shrinkage rate and the wipe performance evaluation shows that the example shows a much smaller value that there is excellent wipe performance, there was no crack generation.

Among the functions of the wiper blade, the function of washing the contaminants in the glass window was evaluated, and the volume change rate and the contamination of the washer fluid were evaluated for the influence of the washer solution. In the contaminated portion, the rubber composition of the example did not cause contamination, and the composition of the comparative example showed conspicuous contamination.

As described above, according to the present invention, the rubber composition for the wiper blade is excellent in wiping performance, prevention of ozone aging due to sunlight, and physical properties such as flexibility and compressive permanent shrinkage, as compared to a composition using only natural rubber. Therefore, it can be applied to wiper blades used in automobiles, etc., which can contribute to performance improvement.

Claims (4)

100 parts by weight of a rubber mixture in which natural rubber and chloroprene rubber are mixed at a weight ratio of 60:40 to 95: 5; 80 parts by weight of carbon black having a particle diameter of 40 to 48 nm and carbon black having a particle size of 26 to 30 nm mixed in a weight ratio of 35:45 to 50:30; 3 to 5 parts by weight of a rubber softener; Sulfur cross-linking agent 0.5 to 2.5 parts by weight; 6 to 7 parts by weight of the crosslinking activator; 2 to 3 parts by weight of a cross-linking accelerator in which N-t-butyl-2-benzothiazole sulfenamide, tetramethylthiuram disulfide and dithio dimorpholine are mixed at a weight ratio of 20:30:50 to 30:40:30; 2 to 4 parts by weight of an antioxidant in which 2-mercaptobenzoimidazole and 2,2′-methylene bis (4-methyl-6-t-butylphenol) are mixed in a weight ratio of 35:65 to 55:45; And A rubber composition for a wiper blade, characterized in that it contains 1.5 to 2.5 parts by weight of an ozone anti-aging agent. The method of claim 1, The rubber softener is a rubber composition for wiper blades, characterized in that the paraffin softener or aromatic oil. The method of claim 1, The crosslinking agent is a rubber composition for a wiper blade, characterized in that the zinc oxide or stearic acid. The method of claim 1, The ozone anti-aging agent is a rubber composition for a wiper blade, characterized in that N-isopropyl-N`-phenol-p-phenylenediamine.

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