KR101520279B1 - Environment-Friendly Rubber Composition - Google Patents

Abstract

The present invention relates to an environmentally friendly rubber composition to which an environmentally friendly vegetable oil is applied in place of a petroleum-based oil containing PCA, which is a harmful substance of the environment. The rubber composition comprises a raw rubber containing at least one selected from natural rubber and synthetic rubber, And a vegetable oil modified with a structure having an acid value of 1 to 10 and a weight average molecular weight of 500 to 3,000 and modified with an oleic triglyceride and a methyl ester, It is possible to produce and supply tires continuously and stably in the future without depletion of resources.

Description

Environment-Friendly Rubber Composition}

The present invention relates to a rubber composition containing a vegetable oil, and more particularly, to an environmentally friendly rubber composition to which an environmentally friendly vegetable oil is applied instead of a petroleum oil containing PCA as a harmful substance.

Today, the demand level of tires is very diverse, and as a tire itself, such as steering stability, noise, rolling resistance, braking force, and abrasion resistance, there is a demand for a technique to appropriately control all characteristics such as pollution and environment friendliness in tire manufacturing.

Among them, the environmental friendliness of tires has been increasing with the basic performance of tires and consumers' demands. Since pollution of the environment is directly related to the maintenance of human life, tire manufacturers are also doing much research on environmentally friendly tires.

In the rubber composition, when the filler is reinforced in the rubber composition having a high viscosity, the flexibility of the compounded rubber is lowered. Therefore, a certain amount of a softener is used for the purpose of improving workability. Paraffinic oil, aromatic oil, naphthenic oil and the like were used as the oil to be used in the tire rubber composition. have. In addition, chemical peptizers or process aids may be used, and low molecular weight polymers may be used. In particular, the rubber compound containing an aromatic oil is excellent in workability such as extrusion and rolling, and minimizes change in physical properties, and is used in rubber compounds in the above-mentioned oils.

In Europe, however, since the European Commission published in 2004 the regulation on all products containing polycyclic aromatic (PCA) suspected of containing carcinogens since 2009, As the development of low PCA containing oils with less than 3% PCA in oil and studies on alternatives to aromatic oils have been carried out, they contain potential or small risks of PCA containing RAE, TDAE, MES, etc. In fact.

Korean Patent Laid-Open Publication No. 10-2002-0064038 discloses a rubber composition containing a vegetable oil. However, compatibility of the vegetable oil with rubber is overlooked. In Korean Patent No. 10-0635615, a palm oil derivative is used as a softening agent, but control of physical properties is difficult.

Accordingly, the present inventors have studied oil that can be applied in place of petroleum-based oil containing PCA, which is an environmentally harmful substance, and found that it is possible to use Oleic Tri Glyceride prepared from a fatty acid extracted from natural vegetable oil instead of conventional petroleum- And Methylester to increase the molecular weight and the number of double bonds so that the modified natural vegetable oil having increased compatibility with the rubber is applied to the rubber composition, the degradation of physical properties before and after aging, which is a problem of natural vegetable oil, and It is possible to provide an environmentally friendly rubber composition capable of solving the problem of blooming and improving the low temperature properties of rubber and the processability upon extrusion, thereby completing the present invention.

Patent Publication No. 10-2002-0064038, Kumho Industrial Co., Ltd. Patent No. 10-0635615, Kumho Tire Co., Ltd.

A problem to be solved by the present invention is to provide a rubber composition which contains oleic triglyceride and methyl ester prepared from a fatty acid extracted from a vegetable oil in place of a petroleum oil as a softening agent to increase molecular weight and double bond number, To the rubber composition by applying the modified natural vegetable oil to the rubber composition to solve the problem of deterioration of the physical properties before and after aging and blooming of the natural oil and to improve the low temperature property of the rubber and the processability upon extrusion, To provide a rubber composition.

In order to solve the above problems, the present invention provides a raw material rubber containing at least one selected from the group consisting of natural rubber and synthetic rubber, silica and softening agent as reinforcing fillers having an acid value of 1 to 10, a weight average molecular weight of 500 to 3,000, There is provided a rubber composition comprising a modified vegetable oil comprising an epichlorohydrin, an epitriglyceride and a methyl ester.

In the rubber composition according to the present invention, the modified vegetable oil preferably contains oleic triglyceride and methyl ester in a weight ratio of 1: 9 to 9: 1.

In the rubber composition, it is preferable that 10 to 100 parts by weight of the silica and 1 to 40 parts by weight of the modified vegetable oil are contained based on 100 parts by weight of the raw material rubber.

In the rubber composition according to the present invention, the oleaginous triglyceride has a structure represented by the following formula (1), and the methyl ester has a structure represented by the following formula (2)

Formula 1

(2)

CH ₃ OOCR

In the general formulas (1) and (2), R 1, R 2 and R 3 are alkyl groups having 10 to 20 carbon atoms and at least one double bond.

The present invention also relates to a rubber composition comprising silica as a reinforcing filler in a raw material rubber containing at least one selected from natural rubber and synthetic rubber, having an acid value of 1 to 10, a weight average molecular weight of 500 to 3,000 and oleic triglyceride And a methyl ester as a softening agent in a master batch or tire.

The rubber composition provided by the present invention is environmentally friendly by removing the harmful substances of PAH by using oleic triglyceride and methyl ester prepared from the fatty acid extracted from natural vegetable oil, Thereby enabling stable tire production and supply and demand.

Hereinafter, the present invention will be described in more detail.

The present invention relates to a raw material rubber containing at least one selected from natural rubber and synthetic rubber, silica and softening agent as reinforcing fillers having an acid value of 1 to 10, a weight average molecular weight of 500 to 3,000, oleic triglyceride And a modified vegetable oil comprising a methyl ester.

In the rubber composition according to the present invention, the raw rubber may be any material as long as it can be used as the raw rubber for the tire rubber composition. Examples of such raw rubber include natural rubber or synthetic rubber alone, And a synthetic rubber in a weight ratio of 1: 9 to 9: 1 may be used.

Examples of the synthetic rubber include synthetic rubbers such as but not limited to styrene-butadiene rubber, butadiene rubber, isoprene-containing styrene-butadiene rubber, nitrile-containing styrene-butadiene rubber, neoprene rubber, chlorobutyl rubber, bromobutyl rubber, It can be rubber.

The raw rubber may be a mixture of two or more kinds of synthetic rubbers. Here, the two types of synthetic rubbers may be raw rubbers mixed at a weight ratio of 1: 9 to 9: 1.

In the tread rubber composition for a tire according to the present invention, the silica used as the reinforcing filler may be any as long as it is used in the tire rubber composition as a reinforcing filler in the art. As an example of such silica, silica having a specific surface area (BET) of 110 to 290 m ² / g, a moisture content of 4.0 to 7.0% and a purity of 80% or more is added in an amount of 10 to 100 Parts by weight may be used. Preferably, when the content of silica is 30 parts by weight or more, the effect is more remarkably manifested.

The modified vegetable oil containing oleic triglyceride and methyl ester, which is a softening agent contained in the tread rubber composition for a tire according to the present invention, has a specific gravity of 1 or less, an acid value of 1 to 10, a weight average molecular weight of 500 to 500, 3,000 is preferably used in the range of 1 to 40 parts by weight based on 100 parts by weight of the raw material rubber.

The modified vegetable oil includes oleyltriglyceride having the following formula (1), thereby increasing the amount of double bonds in the oil, thereby improving the compatibility with the rubber and improving the physical properties as compared with the pure natural vegetable oil. Solves the blooming problem and improves the softening effect of the oil by including methyl esters which are low molecules of the following formula:

Formula 1

(2)

CH ₃ OOCR

In the general formulas (1) and (2), R 1, R 2 and R 3 are alkyl groups having 10 to 20 carbon atoms and at least one double bond.

The modified natural oil may be prepared by mixing oleic triglyceride and methyl ester, which are prepared from fatty acids collected from any one of soybean oil, sunflower seed oil, castor oil, palm oil, grape seed oil or rapeseed oil at a weight ratio of 1: 9 to 9: . When the oleic triglyceride is more than 90%, the processability and softening effect are not sufficient, and when the methyl ester content is 90% or more, the rubber composition becomes too soft. When the weight ratio of oleic triglyceride and methyl ester is 5: 5, the modified natural oil can improve the most excellent physical properties and extrusion performance, and the kind and composition of the natural oil are not particularly limited .

The modified natural vegetable oil has excellent softening effect relative to petroleum oil, so that the physical properties of the rubber compound are lower than that of petroleum-based oil when the same amount is applied. However, when the amount is reduced by 15 to 30%, preferably 25 to 30% The extrusion performance can be improved while maintaining other physical properties.

The modified natural vegetable oil has excellent softening effect and is excellent in compounding and extrusion characteristics and can reduce degradation of physical properties of rubber compound after crosslinking through crosslinking reaction with double bonds present in oil. It is also expected that the compatibility with natural rubber (NR), which is the same natural material, is very good.

The modified natural vegetable oil may be used in the form of a block rubber after being incorporated into a master batch in order to increase the amount thereof. In this case, the modified natural vegetable oil may be added in an amount of 10 to 100 parts by weight based on 100 parts by weight of the masterbatch raw material rubber.

Various additives such as active agents, antioxidants, process oils, vulcanizing agents and vulcanization accelerators used in conventional tire rubber compositions other than the above-mentioned raw rubber, silica and oil may be appropriately selected and used in a predetermined amount . However, these are general components used in the conventional tire rubber composition and are not essential components of the present invention, and therefore, detailed description thereof will be omitted below

On the other hand, the present invention includes a tire containing the tire rubber composition. At this time, the tire includes any one selected from a tire for a passenger car and a tire for a truck / bus.

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

Example  1 and Comparative Example  One

The composition as shown in Table 1 below was precisely weighed, and the fill factor was measured to be 0.70 in a 1.6 L Banbury mixer. The resulting mixture was placed in a Banbury mixer and mixed at 165 DEG C for 20 minutes Was vulcanized to prepare a rubber.

Rubber compounding table (unit: phr ^{1 )} ) division Comparative Example 1 Example 1 Synthetic rubber ^{2 )} 100 100 ZnO ₂ (Zinc Oxide) 3 3 Stearic acid 2 2 Silica 80 80 X-50S ^{3 )} 12.8 12.8 RAE Oil 37.5 - Natural oil ^{4 )} - 27
(28% reduction) sulfur 1.5 1.5 CBS (N-Cyclohexylbenzo thiazole) 1.5 1.5 DPG (N, N-diphenylguanidine) One One 1) phr: Parts per hundred rubber, Weight of mixed material to 100% of raw rubber weight
2) Synthetic rubber: a vinyl content of 55 to 65%, a styrene content of 20 to 30%, a solution polymerization styrene-butadiene rubber
3) X-50S: Silane coupling agent for silica mixed with N-330 and Si-69 at 50:50
4) Natural oils: modified vegetable oils containing oleic triglycerides and methyl esters

Evaluation example  One

The following vulcanization characteristics and physical properties of the rubber prepared in Example 1 and Comparative Example 1 were evaluated, and the results are shown in Table 2 below.

The evaluation methods of the vulcanization characteristics and physical properties are as follows.

Mooney viscosity (Mooney viscosity): was measured according to ASTM standard D 1646. The Mooney viscosity is a value indicating the viscosity of the unvulcanized rubber. The lower the numerical value, the better the workability of the unvulcanized rubber.

Hardness : Measured by a Shore A type hardness tester. The hardness indicates the stability of the specimen to the rigidity of the specimen. The higher the value, the better the stability of the manipulation.

300% Modulus : The tensile strength at 300% elongation was measured according to ASTM standard D 412, and the higher the value, the better the strength.

Elongation : The strain value was measured in a tensile tester by the method of indicating the strain value in% until breaking of the test piece.

Tensile strength : The force per unit area was measured as a value indicating the stress value until the test piece was broken in the tensile tester.

Breaking strength : The force per unit area was measured as a value indicating the stress value until the test piece was torn in the tensile tester.

Wear : The William abrasion tester was used to measure the degree of wear of the rubber by rotating the specimen at high temperature. The lower the value, the better the abrasion performance .

Viscoelasticity : The tan δ value was measured from -60 ° C to 80 ° C under a 10 Hz frequency with a 0.2% strain using a Gabo viscometer. At this time, the temperature with the highest tan δ is defined as the glass transition temperature, and the larger the value of 0 ° C tan δ, the better the braking performance on the wet road surface. The lower the tan δ value of 60 ° C, .

Vulcanization characteristics  And physical property test division Comparative Example 1 Example 1 Mooney viscosity (100 DEG C) 101 101 Cross-linking time (T40) 9.3 10.5 Hardness 70 69 300% modulus
(kgf / cm ² ) Before aging 128 130 After aging 178 182 The tensile strength
(kgf / cm ² ) Before aging 219 217 After aging 217 210 Elongation (%) Before aging 480 470 After aging 380 370 Breaking strength
(kgf / mm ² ) Before aging 37 38 After aging 37 37 William Wear Properties (%) 1.17 1.03 Tg -6.7 -20.6 0 ℃ Tanδ 0.571 0.298 60 캜 Tanδ 0.119 0.091 Wet Skid 37 37

From the results of Table 2, it was confirmed that the abrasion resistance and the rotation resistance were improved while the tensile strength before and after aging was maintained at the same level as that of Comparative Example 1 in Example 1 in which modified natural vegetable oil was applied. Further, it is considered that Tg is lowered and the low temperature performance of the rubber is excellent. In order to cope with the existing petroleum oil, a reduction of about 28% is appropriate as in Example 1, and it is considered that the physical property can be modified by controlling the amount of use according to the user's intention.

Claims (6)

Natural rubbers, and synthetic rubbers, as a reinforcing filler, silica and a softener having an acid value of 1 to 10, a weight average molecular weight of 500 to 3,000, and an olefinic triglyceride and a methyl ester A rubber composition comprising a modified natural vegetable oil. The method according to claim 1,
Wherein the modified natural vegetable oil comprises oleic triglyceride and methyl ester in a weight ratio of 1: 9 to 9: 1. The method according to claim 1,
10 to 100 parts by weight of the silica and 1 to 40 parts by weight of the modified natural vegetable oil are contained based on 100 parts by weight of the raw rubber. The method according to claim 1,
Wherein the oleic triglyceride has a structure represented by the following formula (1), and the methyl ester has a structure represented by the following formula (2).
Formula 1

(2)
CH ₃ OOCR
In the above Formulas 1 and 2, R, R 1, R 2, and R 3 are alkyl groups having 10 to 20 carbon atoms and at least one double bond. A master batch comprising the rubber composition according to any one of claims 1 to 4. A tire made from the rubber composition according to any one of claims 1 to 4.