KR20190134137A - A rubber composition for shoe outsole comprising recycled rubber - Google Patents

Abstract

One aspect of the present invention provides a rubber composition for shoe outsole, including 0.3 to 1.0 parts by weight of a sulfur donor represented by chemical formula (1), based on 100 parts by weight of base rubber including recycled rubber, natural rubber and butadiene rubber. Chemical formula (1) : R-(CH_2)_n-R. In the chemical formula, R is a functional group containing two or more sulfur atoms, and n is one of integers from 1 to 20.

Description

Rubber composition for shoe outsole containing regenerated rubber {A RUBBER COMPOSITION FOR SHOE OUTSOLE COMPRISING RECYCLED RUBBER}

The present invention relates to a rubber outsole rubber composition comprising a regenerated rubber, and more particularly to a shoe that can improve the physical properties by increasing the content of the regenerated rubber, including a sulfur donor, at the same time improve the aging characteristics by heat It relates to a rubber composition for outsole.

In recent years, environmental problems are emerging throughout the society, and polymer and rubber materials used in various household goods, automobile parts, electric and electronic products, etc. are mostly used as a source of environmental pollution. It is becoming.

In particular, rubber wastes generated by rubber products that are widely used as tires, among them, are not naturally decomposed, which is a major cause of environmental pollution such as water quality, soil, and air pollution. If left untreated, the rapidly growing rubber waste can cause serious environmental damage.

In addition, the number of automobile registrations in Korea is increasing every year, and the amount of waste rubber (waste tire) generated accordingly is also increasing every year. Most of the used tires are used as energy sources such as cement production and cogeneration, but they are recycled to increase the added value of recycled rubber. Therefore, development of technology to make products by replacing recycled rubber with natural rubber and synthetic rubber need.

Therefore, in order to properly use resources to prevent environmental pollution, interest and research on the treatment and recycling of industrial waste including polymers and rubber materials have been steadily around the world.

Accordingly, while development of a technology for making products including recycled rubber is underway, recycled rubber is usually a rubber made by crushing waste tires and desulfurizing to be easily reprocessed, but a problem of breaking rubber bonds and remaining crosslinking agents in the desulfurization process. This adversely affects the physical properties of the recycled rubber.

In addition, a method of improving physical properties by using a mixture of sulfur and a peroxide crosslinking mechanism is known, but there is a problem that it is difficult to solve the fundamental physical degradation when using the sulfur and peroxide crosslinking mechanism at the same time.

The present invention is to solve the above-mentioned problems of the prior art, an object of the present invention is to provide a rubber outsole rubber composition, including a sulfur donor, including a recycled rubber having excellent wear resistance while maintaining mechanical properties. .

One aspect of the present invention provides a rubber insole composition comprising 0.3 to 1.0 parts by weight of a sulfur donor represented by the following formula (1) based on 100 parts by weight of the base rubber, including recycled rubber, natural rubber and butadiene rubber.

<Formula 1>

Wherein R is a functional group containing two or more sulfur atoms and n is one of integers from 1 to 20.

In one embodiment, the content of the reclaimed rubber in the base rubber may be 40% by weight or more.

In one embodiment, the content of the natural rubber in the base rubber may be more than 30% by weight.

In one embodiment, the content of the butadiene rubber in the base rubber may be 30% by weight or less.

In one embodiment, the sulfur donor is hexamethylene-1,6-bis (thiosulfate), 1,6-bis (N, N-dibenzylthiocarbamoyldithio) -hexane, or a combination thereof. Can be.

In one embodiment, the rubber outsole rubber composition 30 to 50 parts by weight of filler, 2 to 5 parts by weight of coupling agent, 0.5 to 1.5 parts by weight of crosslinking agent, 0.5 to 1.5 parts by weight of crosslinking accelerator, and 1 to 10 parts by weight of process oil It may further include wealth.

In one embodiment, the filler may be silica, carbon black, or a combination thereof.

In one embodiment, the crosslinking accelerator may include 60 to 80% by weight of thiazole-based accelerator and 20 to 40% by weight of thiuram-based accelerator.

In one embodiment, the process oil may be one selected from the group consisting of paraffin oil, naphthenic oil, aromatic oil, and combinations of two or more thereof.

According to one aspect of the present invention, even when a large amount of regenerated rubber is used by using a sulfur donor, wear resistance can be improved while maintaining mechanical properties.

It is to be understood that the effects of the present invention are not limited to the above effects, and include all effects deduced from the configuration of the invention described in the detailed description or claims of the present invention.

Hereinafter, the present invention will be described in detail. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

Throughout the specification, when a part is "connected" to another part, it includes not only "directly connected" but also "indirectly connected" with another member in between. . In addition, when a part is said to "include" a certain component, this means that it may further include other components, without excluding the other components unless otherwise stated.

One aspect of the present invention provides a rubber insole composition comprising 0.3 to 1.0 parts by weight of a sulfur donor represented by the following formula (1) based on 100 parts by weight of the base rubber, including recycled rubber, natural rubber and butadiene rubber.

<Formula 1>

In the above formula, R is a functional group containing two or more sulfur atoms, n may be one of the integer of 1-20.

The sulfur donor may prevent the reduction during the vulcanization process of each rubber, it may serve as a coupling agent or a crosslinking agent for producing a stable vulcanizate. The sulfur donor is a component used to solve the problem of deterioration of physical properties as the crosslinking agent derived from the recycled rubber remains in a composition containing an excess of recycled rubber more than necessary, and includes an excess recycled rubber In addition to providing sufficient durability to the outsole, these shoe outsoles are environmentally friendly and economical.

The sulfur donor may crosslink or couple each other with the recycled rubber, natural rubber and butadiene rubber constituting the base rubber (heterogeneous rubber crosslink), and may also crosslink or couple each rubber with the same kind (rubber crosslinking) ).

By the crosslinking or coupling of the base rubber, the degree of branching of the regenerated rubber, the natural rubber, and / or the butadiene rubber is increased to the required range, so that the processability and mechanical properties of the rubber composition can be harmonized.

The number of sulfur atoms contained in the functional group R located at both ends of the molecule in the sulfur donor may affect the degree of branching of the crosslinked or coupled base rubber and thus the viscosity and processability. That is, when the number of sulfur atoms is small, the viscosity cannot be lowered to the required level, and when the number of sulfur atoms is excessively high, mechanical properties of the product may be lowered. The number of sulfur atoms contained in the functional group R located at both ends of the sulfur donor may be two or more, preferably two or three.

The content of the sulfur donor may be 0.3 to 1.0 parts by weight based on 100 parts by weight of the base rubber. When the content of the sulfur donor is less than 0.3 part by weight, the viscosity of the rubber composition may be increased, and the workability may be decreased. When the content of the sulfur donor is greater than 1.0 part by weight, the mechanical properties of the shoe outsole may be reduced. The sulfur donor may be hexamethylene-1,6-bis (thiosulfate), 1,6-bis (N, N-dibenzylthiocarbamoyldithio) -hexane, or a combination thereof, but is not limited thereto. It is not.

The hexamethylene-1,6-bis (thiosulfate) may be present as a metal salt represented by the following Chemical Formula 2, specifically, a disodium salt dihydrate (Hexamethylene-1,6-bis (thiosulfate) disodium salt dihydrate).

<Formula 2>

The 1,6-bis (N, N-dibenzylthiocarbamoyldithio) -hexane may be represented by the following Chemical Formula 3.

<Formula 3>

The content of the regenerated rubber in the base rubber may be 40% by weight or more. The regenerated rubber is a rubber that has undergone a desulfurization process, and preferably, may be included in an amount of 50% by weight or more to maximize economics.

The "desulfurization process" is a necessary step in the process of reclaiming the waste rubber after the vulcanization process to add sulfur to the natural rubber to enhance the physical properties.

The content of the natural rubber in the base rubber may be 30% by weight or more. When the content of the natural rubber is less than 30% by weight, the mechanical properties of the rubber composition and the shoe outsole manufactured therefrom may be reduced.

The content of the butadiene rubber in the base rubber may be 30% by weight or less. If the content of the butadiene rubber is more than 30% by weight, the mechanical properties may be partially improved, but the content of the regenerated rubber is relatively low, so it is difficult to realize the effects of eco-friendliness and economics.

The shoe outsole rubber composition may further comprise 30 to 50 parts by weight of a filler, 2 to 5 parts by weight of coupling agent, 0.5 to 1.5 parts by weight of crosslinking agent, 0.5 to 1.5 parts by weight of crosslinking accelerator, and 1 to 10 parts by weight of process oil. .

The coupling agent may include functional groups at both ends, so that functional groups at one end may react with the filler and functional groups at the other end may react with the rubber chain to improve mechanical properties of the shoe outsole.

The coupling agent may be a silane-based, siloxane-based, a mixture thereof, or a polymer thereof, and may be modified by a functional group or a substituent as necessary, and preferably, may be a silane-based coupling agent. Preferably, it may be bis [3- (triethoxysilyl) propyl] tetrasulfide.

The silane coupling agent chemically bonds the surface of the filler silica with the rubber chain to improve the mechanical properties of the rubber composite by improving the interaction and dispersibility between the rubber and the filler. The amount of the coupling agent may be 2 to 5 parts by weight, preferably 3 to 5 parts by weight, but is not limited thereto.

The crosslinking agent is a material that plays a role of crosslinking between the rubber chains, and may impart mechanical strength and chemical stability such as hardness and elasticity to the rubber composition and the shoe outsole. The crosslinker may be sulfur. The content of the crosslinking agent may be 0.5 to 1.5 parts by weight, preferably 1.0 to 1.3 parts by weight. If the content of the crosslinking agent is less than 0.5 parts by weight, the viscosity of the rubber composition may be increased, and workability may be reduced. If the content of the crosslinking agent is more than 1.5 parts by weight, the mechanical properties of the shoe outsole may be reduced.

The crosslinking accelerator is a component that serves to assist the sulfur donor, and shortens the vulcanization time, lowers the vulcanization temperature, improves the quality, has the advantage of economically advantageous by reducing the amount of the vulcanizing agent.

The crosslinking accelerator may be an aldehyde ammonia, aldehyde amine, guanidine, thiourea, thiazole, thiuram, dithio carbomate, xanthate, sulfenamide or mixtures thereof. , Thiazole-based, thiuram-based, sulfenamide-based, or mixtures thereof, and more preferably, thiazole-based and thiuram-based accelerators, but are not limited thereto.

The crosslinking accelerator may include 60 to 80% by weight of a thiazole-based accelerator and 20 to 40% by weight of a thiuram-based accelerator, and when out of the range, mechanical properties of the product may be reduced.

The thiazole-based accelerator is 2-mercapto banjo thiazole, dibenzothiazyl disulfide, sodium-2-mercapto benzothiazole, Zn-salt of 2-mercapto banjo thiazole, cyclo of 2-mercapto banjo thiazole It may be one or more promoters selected from the group consisting of hexylamine salt, wherein the thiuram system is in the group consisting of tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, dipentamethylene thiuram tetrasulfide It may be one or more promoters selected.

The filler may be silica, carbon black, or a combination thereof, preferably silica.

The process oil may be one selected from the group consisting of paraffin oil, naphthenic oil, aromatic oil and a combination of two or more thereof.

The process oil may affect properties such as compatibility with various rubbers, rubber processability, low temperature properties, anti-pollution resistance, aging resistance, elasticity, wear resistance and the like of the product rubber.

The process oil may be an aromatic, naphthenic, or paraffinic oil. In general, the compatibility with rubber may be an aromatic, naphthenic, or paraffinic order, but the butyl rubber may have excellent paraffinic compatibility.

Preferably, it may be a white oil of paraffin oil, which is an oil manufactured under highly refined paraffin oil as a raw material under a long-term accumulated technology and thorough quality control, and excellent oxidation stability, discoloration to light and heat even after long use It is less polluted and has excellent water separation, which does not cause emulsification when mixed with water, and is advantageous for blending special rubber products.

Hereinafter, embodiments of the present invention will be described in detail.

Examples and Comparative Examples

Rubber, metal oxide, stearic acid, anti-aging agent according to the mixing ratio (unit: parts by weight) of Tables 1 and 2 below at a speed of 50 to 70 rpm in a Banbury mixer maintained at 70 ° C. , A surfactant and a metal / fatty acid processing aid were added and mixed for 5 minutes, followed by further adding a filler, a coupling agent, and a process oil, followed by further mixing for 10 minutes.

Again, in the state of maintaining a speed of 40 ~ 60rpm in an open roll mill (Open roll-mill) maintained at 70 ℃, crosslinking agent, crosslinking accelerator in the mixture according to the mixing ratio (unit: parts by weight) of Tables 1 and 2 And a sulfur donor was added and mixed for 5 minutes, and rubber compositions for shoe outsoles of Examples and Comparative Examples were prepared in sheets of 1 to 2 mm, and the mold thickness was 160 ° C. in molds having 2 mm and 5 mm, respectively. Specimens were prepared by press molding for 6 minutes under a press condition of 120 kgf / cm ² .

division EXAMPLE
One EXAMPLE
2 EXAMPLE
3 EXAMPLE
4 EXAMPLE
5 EXAMPLE
6 EXAMPLE
7 Play rubber 40 50 50 40 40 40 40 caoutchouc 30 30 30 30 30 30 30 Styrene / butadiene rubber ¹⁾ - - - - - - - Butadiene rubber ²⁾ 30 20 20 30 30 30 30 Filler (silica ³⁾ ) 40 40 40 40 40 40 40 Coupling Agent ⁴⁾ 3 3 3 3 3 3 3 Processing aid One One One One One One One Metal oxide 5 5 5 5 5 5 5 Stearic acid One One One One One One One Anti-aging One One One One One One One Surfactants One One One One One One One Process oil ⁵⁾ 2 2 2 2 2 2 2 Crosslinking agent (sulfur) 1.2 1.2 1.2 1.2 1.2 1.2 1.2 Crosslinking promoters 1 ⁶⁾ 0.8 0.8 0.8 0.8 0.8 0.8 0.8 Crosslinking accelerator2 ⁷⁾ 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Sulfur donor 1 ⁸⁾ 0.5 0.5 - 0.3 0.4 0.8 One Sulfur donor2 ⁹⁾ - - 0.5 - - - -

division Comparative example
One Comparative example
2 Comparative example
3 Comparative example
4 Comparative example
5 Comparative example
6 Comparative example
7 Comparative example
8 Comparative example
9 Comparative example
10 Play rubber 40 40 50 40 40 40 40 40 30 20 caoutchouc 30 - 30 30 30 30 30 30 30 30 Styrene / butadiene rubber ¹⁾ - 30 - - - - - - - - Butadiene rubber ²⁾ 30 30 20 30 30 30 30 30 40 50 Filler (silica ³⁾ ) 40 40 40 40 40 40 40 40 40 40 Coupling Agent ⁴⁾ 3 3 3 3 3 3 3 3 3 3 Processing aid One One One One One One One One One One Metal oxide 5 5 5 5 5 5 5 5 5 5 Stearic acid One One One One One One One One One One Anti-aging One One One One One One One One One One Surfactants One One One One One One One One One One Process oil ⁵⁾ 2 2 2 2 - - - - 2 2 Crosslinking agent (sulfur) 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 Accelerators1 ⁶⁾ 0.8 0.8 0.8 0.6 0.8 0.8 0.8 0.8 0.8 0.8 Accelerator2 ⁷⁾ 0.4 0.4 0.4 0.6 0.4 0.4 0.4 0.4 0.4 0.4 Sulfur donor 1 ⁸⁾ - - - - 0.1 0.2 1.1 1.5 - - Sulfur donor2 ⁹⁾ - - - - - - - - - -

1) SBR 1502, Kumho Petrochemical 2) KBR 01, Kumho Petrochemical

3) Zeosil 175MP, Rhodia

4) Si-69, Rhodia

5) W-1500, Michang Petrochemical

6) DM, OCI

7) TS, OCI

8) DHTS, Nocil

9) VULCUREN, Lanxess

Experimental Example

Hardness, tensile strength, tear strength, and abrasion resistance (NBS) were measured for the specimens prepared in Examples and Comparative Examples, and the results are shown in Tables 3 and 4 below.

-Shore A: Measured using an Asker A hardness tester according to KS M6518.

Tensile strength (kgf / cm ² ): Tensile strength was measured according to KS M6518. At this time, five test pieces were used for the same test.

Tear strength (kgf / cm): The tear strength was measured according to KS M6518. At this time, five test pieces were used for the same test.

Wear resistance (%): measured using an NBS wear tester (KS M6625). After five or more standardized specimens were tested, the average values were taken as the test values except for the maximum and minimum values.

division Hardness The tensile strength Tear strength NBS wear Example 1 70 166 87 253 Example 2 71 162 93 238 Example 3 71 163 92 240 Example 4 70 160 91 215 Example 5 70 161 90 223 Example 6 71 163 91 237 Example 7 72 163 89 234

division Hardness The tensile strength Tear strength NBS wear Comparative Example 1 71 162 90 165 Comparative Example 2 72 143 59 170 Comparative Example 3 73 160 86 158 Comparative Example 4 69 159 90 167 Comparative Example 5 69 160 89 182 Comparative Example 6 70 132 90 193 Comparative Example 7 71 161 88 197 Comparative Example 8 70 161 89 189 Comparative Example 9 71 148 58 200 Comparative Example 10 72 143 61 210

Referring to Tables 3 and 4, the shoe outsole manufactured by including 0.3 to 1.0 parts by weight of sulfur donor based on 100 parts by weight of the base rubber when the rubber composition for shoe outsole is manufactured, the hardness, tensile strength and NBS wearability was significantly improved while maintaining the tear strength similarly. Also, in Comparative Examples 5 to 8, which contained a sulfur donor but the content was outside the range of 0.3 to 1.0 parts by weight, NBS wearability was compared with that of the other cases. Degraded.

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the invention is indicated by the following claims, and it should be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the invention.

Claims (9)

To 100 parts by weight of base rubber including recycled rubber, natural rubber and butadiene rubber,
A rubber outsole rubber composition comprising 0.3 to 1.0 parts by weight of a sulfur donor represented by Formula 1 below:
<Formula 1>

Where
R is a functional group containing two or more sulfur atoms,
n is one of the integers of 1-20. The method of claim 1,
The content of the reclaimed rubber in the base rubber is 40% by weight or more rubber composition for shoe outsole. The method of claim 1,
The rubber composition for shoe outsole is the content of the natural rubber in the base rubber 30% by weight or more. The method of claim 1,
The content of the butadiene rubber in the base rubber is 30% by weight or less rubber composition for shoe outsole. The method of claim 1,
The sulfur donor is hexamethylene-1,6-bis (thiosulfate), 1,6-bis (N, N-dibenzylthiocarbamoyldithio) -hexane, or a combination thereof. The method of claim 1,
The shoe outsole rubber composition further comprises 30 to 50 parts by weight of filler, 2 to 5 parts by weight of coupling agent, 0.5 to 1.5 parts by weight of crosslinking agent, 0.5 to 1.5 parts by weight of crosslinking accelerator, and 1 to 10 parts by weight of process oil. Rubber composition for. The method of claim 6,
Said filler is silica, carbon black, or a combination thereof. The method of claim 6,
The crosslinking accelerator rubber composition for a shoe outsole comprising 60 to 80% by weight of a thiazole-based accelerator and 20 to 40% by weight of a thiuram-based accelerator. The method of claim 6,
Wherein said process oil is one selected from the group consisting of paraffin oil, naphthenic oil, aromatic oil and combinations of two or more thereof.