KR20000063876A - The manufactural method of compounds for sealing rubber door gasket for drum type washing machine - Google Patents

Abstract

PURPOSE: A rubber gasket composition is provided that prevents leaking water and absorbs the vibration of a drum, not to influence on the body of the drum. CONSTITUTION: The gasket composition comprises 30 to 60 wt% of oil extended synthetic rubber, 5 to 20 wt% of siliceous filler, 5 to 20 wt% of calcium carbonate, 5 to 15 wt% of petrolic softening agent, 0.5 to 2 wt% of vulcanizing promoter, 2 to 10 wt% of processing aid, 0.1 to 3 wt% of polyethylene glycol(PEG), 0.5 to 2 wt% of pigment, 0.1 to 1 wt% of antiaging agent and 0.2 to 1 wt% of conventional rubber vulcanizing sulfur as a curing agent. The preparation of the gasket comprises the step of : mixing the above mentioned components in a conventional mixer(Banbury mixer) in a temperature range of 80 to 130°C within 10min; shaping into a ribbon type sheet having a thickness of 6 to 10mm in a conventional open roll; cooling in a refrigerator; aging for about 12 hrs.; shaping into a desired form by vulcanizing at a temperature of about 140 to 170°C for 3 to 5 min.; and then packaging via the processing.

Description

Composition of rubber gasket for sealing door of drum washing machine and its manufacturing method {The manufactural method of compounds for sealing rubber door gasket for drum type washing machine}

The present invention relates to a composition and a manufacturing method of a rubber gasket mounted between the door and the drum of the drum type washing machine. In detail, the front door and the drum of the drum washing machine are sealed to prevent leakage of water during washing. The present invention relates to a composition of a drum washing machine door sealing rubber gasket and a method for manufacturing the same, which absorb vibration transmission to a main body by vibration of a drum to reduce vibration of a washing machine.

Conventionally, there are products using NBR as a drum washing machine gasket or general synthetic rubber. However, when NBR is used as a material, ozone in air (O ₃ ) is caused by long exposure to sunlight in the air due to the characteristics of the material. As the product ages and cracks, it is more likely to tear or leak. In particular, when using raw rubber that is weak to ozone, this aging problem can cause serious effects. For example, due to aging caused by sunlight, the gasket may be torn when the washing machine is running, which may cause water leakage due to water leakage, and when used indoors, consumer complaints may occur such as water accumulation on the floor.

In addition, even when general synthetic rubber is used, it is difficult to manufacture a product having high physical properties (tensile strength) because the hardness of the product is very low. In order to increase the tensile strength of the product, there is a method of improving the tensile strength by increasing the rubber content by limiting the amount of filler used. However, this method is limited to rubber products having a hardness of 50 (SHORE A) or higher. Increasing the content of rubber is not only good tensile strength, but also has the disadvantage that the product cost is increased due to the increase in raw material costs. In addition, when using a product of high hardness to increase the tensile strength, the vibration generated in the drum and the motor of the washing machine is not absorbed and is transmitted to the washing machine main body, so that the noise and vibration are severe when the washing machine is operated.

In order to solve the above problems, the present invention maintains a high tensile strength even at a hardness of about 40 (SHORE A) by using the oil-containing GRADE in the synthetic rubber itself to exhibit the properties of strong tensile strength even at low hardness (Tension strength = 100kgf / cm ² or more), which not only has excellent durability even when the washing machine is operated by excessive vibration or rotation, but also has excellent ozone resistance using EPDM as synthetic rubber. It has the advantage of hardly aging by sunlight even when exposed to sunlight, and it has excellent compatibility between raw material rubber and softener using P-6 petroleum softener, and the amount of volatilization during molding due to high molecular weight of softener itself. In addition, less foreign matters are generated due to the vaporization of oil in the mold formed at a high temperature. By using POLYETHYLENE GLYCOL which enables hydrogen bonding to enhance the mixing of radish, it has the advantage of high strength of molded products by uniform mixing of raw material rubber and silica and bonding between molecules. In order to provide a composition for a rubber gasket of a drum type washing machine using a small amount of BLUE and YELLOW colors and a method of manufacturing the same, it is a technical problem to be achieved by the present invention.

In order to achieve the above object, the present invention is 30 to 60% by weight of oil-added synthetic rubber, 5 to 20% by weight of precipitated silica (PRECIPITATED SILICA), the main ingredient of SiO ₂ , 5 to 20% by weight of calcium carbonate, petroleum 5 to 15% by weight system softener, 0.5 to 2% by weight vulcanization accelerator to increase the vulcanization rate, 0.1 to 3% by weight processing aid 0.5 to 2% by weight pigment, 0.1 to 1% by weight antioxidant The present invention relates to a composition of a rubber gasket for sealing a drum washing machine door composed of a composition ratio of weight%, and a manufacturing method thereof.

The present invention has a characteristic of having 30 to 70% of oil in the raw material rubber itself as a synthetic rubber and having high tensile strength even at low hardness by using EPDM having a high molecular weight, and the material is registered in Korean Patent Publication No. 208314. The adhesive thermoplastic composition which consists of EPM vulcanized rubber, EPDM vulcanized rubber, and a thermoplastic elastomer is disclosed, and the characteristic is as already disclosed,

In order to prevent aging due to heat when used at high temperature for a long time, an anti-aging agent for improving heat resistance was used. As a result, the problems such as the increase in hardness and the elongation of tensile strength of the product due to the high heat (boiling method) during washing of the drum washing machine were overcome. In order to prevent aging due to abrasion of the product and to improve elasticity, silica-based fillers are used, and the silica-based fillers and the EPDM rubber have good mixing properties, and hydrogen bonding is possible to make intermolecular bonds. Polyethylene glycol (POLYETHYLENE GLYCOL) was used. In particular, the gray color product is located on the front side of the drum washing machine, so it uses a small amount of blue pigment to improve the vividness of the product.

In the present invention, the silica-based filler is PRECIPITATED SILICA, and the main component is SiO ₂ , which is white powder as colorless, odorless, and odorless fine particles. Due to its high surface area, it is easy to disperse with rubber and is often used as a reinforcing filler in colored rubber formulations that do not use carbon black, which is a reinforcing filler, and a paraffinic P-6 oil is used as a petroleum softener. As a vulcanizing aid, dithicarcarmate, thiazole, and thiuram-based accelerators that increase the vulcanization rate were used. ZnO), stearic acid (STEARIC ACID) and polyethylglycol (POLYETHYL GLYCOL (PEG)) were used, and the pigments were prepared in the color desired by the user using TiO2 (white), BLUE color, YELLOW color, etc. Styrenated phenol (STYRENATED PHENOL) and sulfur for rubber vulcanization were used as a curing agent.

Hereinafter, the manufacturing method will be described in detail with reference to the following examples.

Example 1

30 to 60% by weight of oil-added synthetic rubber, 5 to 20% by weight of PRECIPITATED SILICA as filler, 5 to 20% by weight of calcium carbonate, 5 to 20% by weight of paraffinic P-6 blended oil with petroleum softener 15% by weight, the vulcanization accelerator to increase the vulcanization rate of the vulcanization accelerator (DITHCARVAMATE), thiazole (TIIAZOLE) and thiuram compound 0.5 to 2% by weight, usually as a processing aid 2 to 10% by weight of zinc-activated zinc oxide (ZnO), stearic acid (STEARIC ACID) -based compound, 0.1 to 3% by weight of polyethylglycol (POLYETHYL GLYCOL (PEG)), 0.5 to 2% by weight of pigment, as an antioxidant Styrenated phenol (STYRENATED PHENOL) 0.1 to 1% by weight, the composition of the rubber vulcanizing sulfur in a composition ratio of 0.2 to 1% by weight of the composition and then weighing the composition 80-130 using a conventional mixer (BANBURY MIXER) After sufficient mixing within 10 minutes in the temperature range of ℃, the usual 60 ~ 80 ℃ Peunrol (OPEN ROLL) at 2 by using a single blade makes a kneaded material of the ribbon to form 6~10mm thickness. At this time, the ribbon-shaped kneaded material prepared as the sheet temperature of about 60 to 80 ℃ is moved to the cooling device to cool.

Example 2

The ribbon prepared and cooled in Example 1 is moved to the loading tray and aged for about 12 hours to stabilize the physical properties of the mixture, and then a temperature of about 140 ° C. to 170 ° C. and a time of 3 minutes to 5 minutes in a conventional rubber injection molding machine. By using the rubber injection machine to form the desired shape by vulcanization, the reaction starts not only to make the mixture uniform and soft in the screw and chamber inside the injection machine, but also to vulcanize the reaction immediately while the rubber is stored in the screw and the chamber. In addition, there is no difficulty in molding even in a complicated shape, and there is an advantage of fast production speed.

Example 3.

The molded product using the rubber injection machine in Example 2 was packaged through a post-processing process to produce a rubber gasket for sealing the drum washing machine door.

Comparative example

division Condition General Synthetic EPDM (existing use) NBR (existing use) OIL EXTENDED EPDM Tensile strength (kgf / cm ² ) 25 ℃, universal testing machine 30-50 100-120 110 to 150 Ozone performance Ozone tester 50pphm, 40 ℃, left for 168 hours No problem Abnormality (cracks occur) No problem

The present invention as described above has the advantage of using a large amount of filler in the case of the mixture of the same hardness due to the use of OIL EXTENDED EPDM containing the OIL in the raw material rubber itself has the advantage of reducing the raw material cost and high tensile strength, synthesis As the rubber uses EPDM which has very strong weather resistance (ozone resistance), there is almost no aging due to ozone even in the long-term use of the washing machine.Therefore, there is no risk of leakage caused by aging of the gasket in case of long-term use. In this case, by using an anti-aging agent for improving heat resistance in order to prevent aging due to heat, thereby overcoming problems such as increase in hardness and elongation of the product due to high heat (boiling method) during washing of the drum washing machine. In addition, it prevents aging due to abrasion of the product and uses the white silica-based filler with excellent elasticity and reinforcing effect, and not only has improved properties such as wear resistance, tear strength, and restoring force, but also raw material rubber and silica-based filler. In order to facilitate the mixing of molecules and the binding between molecules, there is an advantage in that the binding strength between raw materials and fillers is increased. In addition, by adding a small amount of pigment, the color of the product is clear and has a clear effect, and the appearance of the product is more beautiful than when the pigment is not used, and by using a rubber injection molding method, the compression molding method after conventional sheet punching Compared to the production speed is significantly faster than the manual process of punching out the kneaded material, the incidence of color defects due to the incorporation of foreign matters is low as well as the productivity is improved as the deleted process.

Claims (3)

Rubber gasket composition for drum washing machine door sealing, 30 to 60% by weight of oil-added synthetic rubber, 5 to 20% by weight of silica filler, 5 to 20% by weight of calcium carbonate, 5 to 15% by weight of petroleum softener, 0.5 vulcanization accelerator -2% by weight, 2-10% by weight of processing aids, 0.1-3% by weight of POLYETHYL GLYCOL (PEG), 0.5-2% by weight of pigments, 0.1-1% by weight of anti-aging agent, sulfur for rubber vulcanization 0.2-1 Rubber gasket composition for sealing the drum washing machine door, characterized in that the composition by weight and composition of the weight percent. The method of claim 1, wherein the silica-based filler is a precipitated silica (PRECIPITATED SILICA), the petroleum softener is a paraffinic (PARAFINE) -based P-6 blending oil, the vulcanization accelerator is DITHIOCARVAMATE, thia THIAZOLE, and TIURAM compounds, the processing aid is a compound of zinc (ZnO), stearic acid (STEARIC ACID) and polyethylglycol (POLYETHYL GLYCOL (PEG)), the anti-aging agent Styreneated phenol (STYRENATED PHENOL) rubber gasket composition for sealing the door of the drum washing machine. In the manufacturing method of rubber gasket for sealing door of drum washing machine, 30 ~ 60% by weight of oil-added synthetic rubber, 5 ~ 20% by weight of PRECIPITATED SILICA, 5 ~ 20% by weight of calcium carbonate, paraffin ( 5-15% by weight of PARAFINE P-6 blended oil, 0.5-2% by weight of DITHIOCARVAMATE, THIAZOLE, and TIURAM compound, zincated (ZnO), stearin 2-10% by weight of acid compound, 0.1-3% by weight of polyethylglycol (PEG), 0.5-2% by weight of dye, 0.1-1% by weight of styrenated phenol (STYRENATED PHENOL) After the mixture was mixed at a composition ratio of 0.2 to 1% by weight of sulfur in a temperature range of 80 to 130 ° C. within 10 minutes using a general mixer (BANBURY MIXER), the mixture was sufficiently mixed in a normal OPEN ROLL of 60 to 80 ° C. Using two blades, it was made into a ribbon-shaped mixture with a thickness of 6 to 10 mm and then moved to a cooling device to cool it. After aging for about 12 hours, and then vulcanized at a temperature of about 140 ℃ to 170 ℃ and a time of 3 minutes to 5 minutes in a conventional rubber injection molding machine to be molded into a desired shape and then manufactured by packing through the processing process Method for producing a drum washing machine door sealing rubber gasket characterized in that.