KR100454284B1 - Preparation of a rubber composition having a high elongation - Google Patents

Abstract

The present invention relates to a method for producing a highly stretchable rubber composition, and more particularly, by using natural rubber as a substrate and undergoing a two-step plasticization process, high extensibility can be given to maximize slip resistance characteristics. As it adds hard carbon, white carbon and mica, it can show various colors according to the pigment used, which enhances fashion. In particular, when the new rubber composition is applied to a shoe outsole, the outsole with enhanced functionality and fashion The present invention relates to a method for producing an improved high stretch rubber composition.

Description

Preparation method of high elastic rubber composition {Preparation of a rubber composition having a high elongation}

The present invention relates to a method for producing a highly stretchable rubber composition, and more particularly, by using natural rubber as a substrate and undergoing a two-step plasticization process, high extensibility can be given to maximize slip resistance characteristics. As it adds hard carbon, white carbon and mica, it can show various colors according to the pigment used, which enhances fashion. In particular, when the new rubber composition is applied to a shoe outsole, the outsole with enhanced functionality and fashion The present invention relates to a method for producing an improved high stretch rubber composition.

At present, various attempts have been made to maximize fashion with high performance and functionalization based on low specific gravity in the development of footwear materials. In order to reduce the weight and low specific gravity of the material for shoes, foam materials are used a lot, and the low specific gravity foam is used for midsoles, insoles and outsoles of shoes. Therefore, when the foam material is used, it is possible to lighten the shoes, and the cushion and walking comfort can be given, so the function of the midsole and insole can be said to be almost completely performed at present.

However, unlike the midsole or insole of the shoe, the outsole has a much higher degree of wear than the midsole or insole that does not come in direct contact with the road because the outsole is substantially in contact with the road surface. High abrasion resistance is required, and there is an urgent need to reinforce elasticity and slip resistance to meet stability during walking and to mitigate the impact on the foot.

However, the above problem is not solved when the existing foam is used as the outsole of the shoe, it required the development of another technology.

Therefore, in order to improve the competitiveness of the shoe industry, the expression of wear resistance and slip resistance at the rubber level is required. Therefore, even when used in the outsole of shoes, it is necessary to develop materials and technologies that can exhibit the above wear resistance and slip resistance characteristics while being lightweight. .

In general, highly elongated rubbers exhibit low elastic modulus and elasticity in a wide range. When the external force is removed, there is no loss of energy due to hysteresis. Outsole requiring slip resistance and shock absorption Can be used as a part of

When the high-strength rubber is used as a part of the outsole requiring shock absorption, if a part of the outsole slightly protrudes toward the ground, and the high-strength rubber is used inside the protruding portion, a large amount of the impact applied to the foot from the ground Since it is applied to the protruding portion, the high-strength rubber inserted into the protrusion due to the impact received at this time is deformed.

Due to the energy consumed in the deformation of the high-strength rubber, the impact applied to the body from the ground can be alleviated a lot, and after the external force is removed, the rubber deformed by the conversion of energy returns to the shape before deformation. Movement or walking is also possible by the kinetic energy of.

Hereinafter, the various methods proposed for high-performance and high-functionalization of the shoe outsole are as follows.

There have been many attempts to introduce the characteristics of rubber products to enhance the function of shoe outsoles. In other words, one of the various physical properties of the rubber may be used as a part of the shoe by maximizing one of the physical properties that can exhibit the desired effect when introduced into the outsole of the shoe and its properties to the material of the outsole for shoes.

As an example of the method, rubber made of a composition that maximizes extensibility, which is one of the greatest properties of a rubber product, is excellent in slip resistance and can be applied as a part of a shoe outsole.

As the above method, conventional methods such as the use of a tackifier, the use of a material having excellent shock absorption properties, or the use of a special kind of rubber have been used.

However, when the tackifier is used in the above-described method, when the outsole manufactured is stored for a long time, the tackifier is oozed out onto the surface of the rubber molding, and thus foreign matter such as dust adheres to the tackifier, thereby slipping. There is a problem that the resistance characteristics are significantly lowered.

In addition, when using a material having excellent shock absorbing properties or a rubber having a special function as a base material, the material has a problem that the price competitiveness of the manufactured shoes is lowered because the material is generally expensive.

In addition, in general, the rubber composition used as a shoe outsole has been used as a carbon black filler for the balance of hardness and physical properties. However, in view of the functionality and the fashion required for the current shoe, the shoe outsole rubber using carbon black is pointed out as a problem that only a black color can be expressed without showing a variety of colors.

However, when white carbon or the like is used without using the carbon black described above, physical properties such as hardness imparted by the carbon black cannot be sufficiently satisfied, and thus a desirable solution thereof is urgently needed.

Therefore, it is necessary to develop a rubber composition that can be manufactured economically by providing slip resistance and shock absorbing property to the above-mentioned problem and various colors can be used, and do not use expensive raw materials. It is becoming.

Thus, the inventors of the present invention can be used as a component of the excellent slip resistance and shock-absorbing material in terms of high functionalization, and can show a variety of colors as a result of research efforts to produce a highly elastic rubber composition having a fashion, natural rubber It can be used as a raw material, but it can enhance extensibility by going through two-stage plasticization process, using white carbon, hard coal and mica as a brightly colored filler to enhance the fashionability, and to be degraded by the use of the filler When using a composition containing a coupling agent for increasing the physical properties such as hardness can be produced a rubber composition that can be effectively used in the manufacture of shoe outsole, and also found that the above problems can be solved The present invention has been completed.

Accordingly, the present invention provides a method for producing a new high-strength rubber composition using natural rubber as a raw material but undergoing a two-step plasticization process, which is enhanced in elongation, and which enhances fashionability by using light colored fillers. Its purpose is.

The present invention provides a method for producing a rubber composition consisting of a base rubber, a filler and an additive, the process of forming a natural rubber of one step calcined natural color rubber in a roll mill of 30 to 40 ℃ with the base rubber; 5 to 120 parts by weight of a filler selected from hard coal, white carbon and mica with respect to 100 parts by weight of the base rubber; 0.5 to 2.0 parts by weight of a coupling agent; 0.2-1.0 weight part of crosslinking adjuvant; 3.0 to 10.0 parts by weight of a metal oxide and 0.5 to 3.0 parts by weight of stearic acid as a vulcanizing stabilizer; 0.05 to 2.0 parts by weight of antioxidant; 0.5 to 3.0 parts by weight of an antistatic agent; And adding 0.1 to 2.0 parts by weight of the pigment and calcining and kneading in a kneader at 120 to 130 ° C. to form a two-stage plasticized rubber kneaded product; And 1.0 to 4.0 parts by weight of sulfur after cooling the plasticized rubber kneaded product; It is characteristic in the manufacturing method of the highly extensible rubber composition which adds 0.1-3.0 weight part of vulcanization aids, and knead | mixes in a roll mill.

Hereinafter, the present invention will be described in detail.

The present invention uses a light-color natural rubber as a base material is subjected to a two-stage plasticization process to give extensibility, which is a characteristic of the conventional natural rubber, to maximize the slip resistance characteristics, without using carbon black as a filler By using bright color fillers such as white carbon, mica, etc., fashion can be used in various colors. Functionality and fashionability can be improved by using a coupling agent to improve the compatibility between the filler and the base material rubber. This reinforcement is characterized by a highly stretchable rubber composition that can be effectively applied to a shoe outsole.

Referring to the high-strength rubber composition of the present invention in detail by component.

First, natural rubber is used as a raw material of the rubber composition according to the present invention. Since the natural rubber has high extensibility, it is suitable for the production of a rubber composition having excellent anti-slip properties, which is an object of the present invention. If color-based natural rubber is used, various colors can be applied and additional effects may be obtained.

In general, sulfur and vulcanizing aids may be added to give higher elasticity in preparing rubber compositions.

In the present invention, both sulfur and insoluble sulfur may be used in the case of sulfur. In particular, insoluble sulfur is a sulfur that does not dissolve in carbon disulfide, and thus there is an advantage in that a rubber product having a vivid color can be obtained because blooming does not occur in unvulcanized rubber. The amount used is 1.0 to 4.0 parts by weight based on 100 parts by weight of the substrate in consideration of the physical properties of the product.

The vulcanizing aid is used 0.1 to 3.0 parts by weight in consideration of physical properties with respect to 100 parts by weight of the substrate, the vulcanizing aid is, for example, 2-mercapto benzothiazole, 2-benzothiazole disulfide, tetramethyl thiuram disulfide, Tetramethyl thiuram monosulfide, oxydiethylene benzo thiazole sulfenamide and cyclohexyl benzothiazole sulfenamide can be used.

In contrast to the conventional use of carbon black as a filler for the balance of physical properties, including the hardness characteristics of rubber vulcanizate, in the present invention, a light-colored filler is used, and specifically, for example, alone or any of hard coal, white carbon and mica. Mixtures of one component can be selected.

In this case, when the hard coal is used, the amount is preferably 20 to 80 parts by weight. If the amount is less than 20 parts by weight, the reinforcing effect is hardly exhibited. If white carbon is used, the amount of use is preferably 5 to 10 parts by weight. If the amount is less than 5 parts by weight, the reinforcing effect is hardly exhibited. In addition, when the mica is used, the amount is preferably 10 to 30 parts by weight. If the amount is less than 10 parts by weight, the reinforcing effect is hardly exhibited.

When white carbon is used as a filler, since the white carbon is made of an inorganic material, compatibility with the base rubber, which is an organic material, is not good, and thus, various coupling agents are used since the physical properties of the rubber kneaded product do not improve significantly.

The coupling agent is 0.5 to 2 parts by weight based on 100 parts by weight of the substrate, specific examples of the coupling agent that can be used, for example, bis- [3- (triethoxysilyl) -propyl] tetrasulfide, 50% bis- [3- (triethoxysilyl) -propyl] tetrasulfide, bis- [3- (triethoxysilyl) -propyl] tetrasulfide coated with white carbon, 3-mercaptopropyl crymethoxy silane, 3- Animopropyl triethoxy silane, tri- (2-methoxyethoxy) vinyl silane, and the Chartwell ratio 505 · 1 having a mercapto group and the Chartwell ratio 600 having a sulfide group can be used.

In addition, in the case of using white carbon, a crosslinking aid may be used in an amount of 0.2 to 1.0 parts by weight based on 100 parts by weight of the base material to assist the activation of the crosslinking system. The crosslinking aid may be selected from polyethylene glycol, diethylene glycol or actiol.

As described above, when white carbon or the like is used as the filler, the compatibility between the natural rubber and the white carbon, which are the raw materials, can be improved by increasing the coupling agent and the crosslinking assistant, and the crosslinking efficiency can be increased.

Moreover, 3-10 weight part of zinc oxide which is a metal oxide, and 0.5-3 weight part of stearic acid are used with respect to 100 weight part of base materials as a vulcanization stabilizer.

In the case of general rubber moldings, when exposed to the air for a long time, an antioxidant is used because cracks are generated by oxygen and ozone in the air, and the amount thereof is used in an amount of 0.05 to 2.0 parts by weight based on 100 parts by weight of the substrate. Specifically, for example, octadecyl 3,5 di-tert-butyl-4-hydroxy hydrocinnamate, tetrakis [methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate) Methane, thiodiethylene bis 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, 1,2-bis (3,5-di-tert-butyl-4-hydroxyhydrocinnamoyl) Hydrazine, calcium bis [monoethyl (3,5-di-tert-butyl-4-hydroxybenzyl) phosphate], 1,3,5-tris (3,5-di-tert-butyl-4-hydroxy Hydroxybenzyl) -S-triazine 2,4,6 trione and tris (2,4-di-tert-butylphenyl) phosphite.

In order to improve the workability, 0.5 to 3.0 parts by weight of the antistatic agent and 0.1 to 2.0 parts by weight of the pigment are used for 100 parts by weight of the base material. Highly stretchable rubber compositions that can be used can be prepared.

As such, simply showing the components included in the rubber composition according to the present invention can be summarized as follows.

In addition, in the case of manufacturing the rubber composition of the present invention, the plasticizing process is carried out twice to increase plasticity to a suitable level for the production of shoe outsoles.

Plasticization, ie, the Soviet Union, refers to the increase in plasticity by reducing the viscoelastic properties by reducing the molecular weight of rubber molecular chains by breaking or intertwining the chain molecules by mechanical shearing force or chemical action on raw rubber. For large, uneven natural rubber, this is a necessary process.

Plasticization of rubber can be divided into low temperature and high temperature

In the case of low-temperature sorption, it proceeds using a roll mill. Rubber is subjected to mechanical compressive shear force between two rolls, and the rubber molecules are cut, and the end of the cutting molecules is stabilized by oxygen in the air, resulting in low molecular weight and increased plasticity. .

High-temperature sorption is mainly used in closed kneaders because the rubber is used at temperatures above 120 ° C. In high-temperature sorption, the mechanical shearing force is hard to occur because the rubber is soft, and the oxidation reaction by oxygen in the air is rather difficult. Is the main factor.

When these two methods are used in parallel, the Soviet Union of the high molecular weight portion of the rubber is advanced by low temperature sorption, and the Soviet Union of the low molecular weight portion of the rubber is advanced by the high temperature sorption, so that the rubber can be uniformly plasticized as a whole.

That is, the first of the plasticization process for producing the rubber composition of the present invention is to calcined the base rubber by mechanical shear force in a low-temperature roll-mill, the natural rubber used as the substrate is a low temperature of 30 ~ 40 ℃ First, the plasticizer was first calcined using a roll mill, and then the plasticizer was added to the first calcined base rubber by adding fillers and other additives, which are used in the present invention, in a kneader at 120 to 130 ° C. And kneading.

At this time, if the temperature of the roll mill is less than 30 ℃ overload occurs in the machine, if it exceeds 40 ℃ mechanical shear force does not appear large. In addition, the temperature of the kneader is 120 to 130 ° C. If the temperature is less than 120 ° C, chemical plasticization does not appear much, and if it exceeds 130 ° C, problems in workability appear.

By the primary plasticization process as described above, the base rubber is well kneaded with the constituents added next, and is highly extensible while undergoing the second plasticization process in the next high temperature kneader, A rubber composition suitable for outsole having a shoe is prepared.

Since the rubber composition according to the present invention has a high plasticity through the plasticizing process by the mechanical shearing force and the plasticizing process made in the high temperature kneader as described above, when manufacturing the outsole for shoes using the same This will have a very desirable effect of being enhanced.

As described above, the rubber composition according to the present invention uses natural rubber as a base material, but introduces excellent physical properties of the base rubber into the outsole of the shoe by adjusting the blending ratio so that the mixing and kneading of the base material and additives is performed well, and the filler By using a bright color filler such as white carbon as a solution to the problem that the color of the existing foam all appeared in black can represent a variety of colors, it is particularly useful for manufacturing a shoe outsole emphasizing fashion.

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

Example 2

After calcining the natural rubber, which is a base material, in a roll mill at 30 ° C. for about 15 to 20 minutes, 30 parts by weight of hard coal as a filler, 5 parts by weight of zinc oxide as a vulcanizing stabilizer, 2 parts by weight of stearic acid, and an antioxidant are added to 100 parts by weight of the substrate. 1.0 part by weight of octadecyl 3,5 di-tert-butyl-4-hydroxy hydrocinnamate, 1.5 parts by weight of a span as an antistatic agent and 0.5 parts by weight of an orange pigment in a kneader at 120 ° C. for about 20 minutes to knead and Plasticized.

The calcined rubber kneaded product was cooled and kneaded in a roll mill by adding 3.0 parts by weight of general sulfur and 0.3 parts by weight of tetramethyl thiuram monosulfide as a vulcanizing aid.

Thereafter, the appropriate crosslinking time was measured and the kneaded material was put into a mold under the conditions of 155 ° C. and 150 kg / cm 2, followed by press molding to prepare a rubber for shoe outsole according to the present invention, and the characteristics thereof are shown in Table 3 below. .

Example 3

After calcining the natural rubber, which is a base material, in a roll mill at 30 ° C. for about 15 to 20 minutes, 5 parts by weight of zinc oxide as a vulcanizing stabilizer, 2 parts by weight of stearic acid, and octadecyl 3,5 di- as antioxidant to 100 parts by weight of the substrate 1.0 parts by weight of tert-butyl-4-hydroxy hydrocinnamate and 6 parts by weight of white carbon as a filler and 0.6 parts by weight of bis- [3- (triethoxysilyl) -propyl] tetrasulfide as a coupling agent polyethylene as a crosslinking aid 0.3 parts by weight of glycol and 0.5 parts by weight of the purple pigment were added to a kneader at 120 ° C. for kneading and calcining for about 20 minutes.

The calcined rubber kneaded product was cooled and kneaded in a roll mill by adding 2.75 parts by weight of insoluble sulfur, 1.0 part by weight of 2-benzothiazole disulfide, and 0.1 part by weight of tetramethyl thiuram disulfide as a vulcanizing aid.

After that, the appropriate crosslinking time was measured, and the rubber kneaded material was put into a mold under the conditions of 155 ° C. and 150 kg / cm 2, followed by press molding to prepare a rubber for shoe outsole according to the present invention. It was.

Comparative example

Outsole rubber, which is currently commonly used, was used in the test as a comparative example, and the results are shown in Table 3 below.

Test Example

Elongation and hardness were measured using a shoe outsole made of a rubber composition according to Examples 2 to 3 and a shoe outsole of a comparative example used in the related art, and are shown in Table 3 below.

<Elongation rate>

The elongation rate of the prepared sheet was measured by using a die cutter. At this time, five test pieces were used in the same test, and the measurement conditions are shown in Table 3.

<Hardness>

Hardness was measured according to ASTM D-2240 by Asker A type hardness tester. At this time, the measurement was repeated five times and the average value was defined as hardness.

As shown in Table 3 above, Examples 2 to 3, which are shoe insoles made of the rubber composition according to the present invention, exhibited an elongation of 700% or more, and a comparative example of shoe outsoles used in the past was 300 to 400%. It can be seen that the extensibility is significantly higher compared to that, the hardness is shown in Examples 2 to 3 according to the present invention 36 to 50, the comparative example is represented to 40 to 50, the hardness of the conventional shoe outsole Compared with, it showed high characteristics without any difference.

In addition, in the rubber compositions of Examples 2 to 3, all of the conventional comparative examples are shown in black, and since the color can be variously adjusted according to the type of pigment to be added, the rubber composition according to the present invention is applied to a shoe outsole. If there is an effect that can improve the fashion.

As described above, according to the rubber composition according to the present invention, it is possible to increase the stretchability and to exhibit various colors, so that when used in shoe outsoles, the stretchability is approximately two times higher than that used in the conventional shoe outsoles. The non-slip property is enhanced, the problem that the conventional shoe outsole is manufactured only in black is improved to apply a variety of colors there is a desirable effect that can produce a shoe outsole for enhanced fashion.

Claims (7)

delete delete delete delete delete delete In the method for producing a rubber composition consisting of a base rubber, a filler and an additive, Forming a natural rubber, which is calcined in one step, in a roll mill of light-colored natural rubber with a base rubber of 30 to 40 ° C; To the plasticized natural rubber, based on 100 parts by weight of the base rubber 5 to 120 parts by weight of a filler selected from hard coal, white carbon and mica; 0.5 to 2.0 parts by weight of a coupling agent; 0.2-1.0 weight part of crosslinking adjuvant; 3.0 to 10.0 parts by weight of a metal oxide and 0.5 to 3.0 parts by weight of stearic acid as a vulcanizing stabilizer; 0.05 to 2.0 parts by weight of antioxidant; 0.5 to 3.0 parts by weight of an antistatic agent; And adding 0.1 to 2.0 parts by weight of the pigment and calcining and kneading in a kneader at 120 to 130 ° C. to form a two-stage plasticized rubber kneaded product; And 1.0 to 4.0 parts by weight of sulfur after cooling the plasticized rubber kneaded product; Process of adding 0.1 to 3.0 parts by weight of a vulcanizing aid and kneading in a roll mill Method for producing a high extensibility rubber composition, comprising a.