KR100777492B1 - Styrene-based sement composition - Google Patents

Abstract

A styrene-based cement composition is provided to improve the adhesion and green adhesive strength of a rubber mixture, thereby preventing the separation of interface. A cement composition comprises 100 parts by weight of a rubber material which comprises 5-15 parts by weight of a liquid isoprene rubber, 30-50 parts by weight of a solution polymerization styrene-butadiene rubber containing 30-50 wt% of styrene and 30-50 wt% of vinyl component, 10-50 parts by weight of an emulsion polymerization styrene-butadiene rubber containing 30-50 wt% of styrene and 30-50 wt% of vinyl component, and 5-15 parts by weight of a butadiene rubber; 40-70 parts by weight of carbon black; 1-5 parts by weight of zinc oxide; 1-3 parts by weight of stearic acid; 1-3 parts by weight of a heat resistant antiaging agent; 2-7 parts by weight of a copolymer of styrene and alpha-methyl styrene; 1-3 parts by weight of a process oil; 0.1-2.0 parts by weight of sulfur; 0.5-3.0 parts by weight of insoluble sulfur; 0.5-2.0 parts by weight of a vulcanization accelerator; and 50-95 parts by weight of a nonaromatic solvent.

Description

Styrene-based cement composition {STYRENE-BASED SEMENT COMPOSITION}

The present invention relates to a styrene rubber-based liquid cement composition which has excellent adhesion and maintains adhesion for a long time. More specifically, styrene provides adhesion between rubbers by dissolving a specific rubber and a binder in a non-aromatic solvent. A rubber based cement composition.

In the rubber industry, various substances such as rubbers and pharmaceuticals are mixed and used according to functions and elements, and the main components of the rubber composition are different depending on the combination thereof. In recent years, rubber products including tires have been variously demanded and have been used harshly. According to this usage trend, various chemicals contained in rubber during the processing of rubber semi-finished products are exposed to the rubber surface according to the environment and time, and the adhesiveness of the interface during the process of combining the rubber semi-finished products and the interface adhesion after vulcanization decrease. There is a problem.

In particular, in recent years, as the high styrene-containing rubber or silica content in the rubber composition increases, the interfacial adhesion and adhesion between rubbers are significantly decreased. In order to prevent such a problem, it is essential to maintain proper adhesiveness of rubber products and to maintain dimensional stability of all semi-finished products during processing of rubber products.

Thus, there is a further need for the use of binder materials that impart cohesion and adhesion suitable for the properties of the rubbers used.

Currently, most rubber industries apply latex rubber such as natural rubber as a binder. When it is applied to semi-finished products using isoprene rubber, it maintains overall performance, especially stickiness is maintained for a long time. KNOTY tearing behavior at the interface shows excellent interfacial adhesion, but when it is applied to styrene rubber-based rubber compound, it is extremely miscible and the interface separation occurs at the interface of rubber semi-finished product.

In particular, during the tire manufacturing process, since the tire is manufactured by combining several semi-finished products, rubber cement used to improve the interfacial adhesion strength between the semi-finished rubber products plays an important role. Accordingly, in the manufacture of tires, an optimal cement composition is required according to the raw rubber used. In particular, in recent years, as the performance of tires is accelerated, the harsher the conditions for use, it is essential to maintain the bonding force between the rubbers forming the tire.

In addition, manufacturers of rubber products, including tire companies, have recently conducted a lot of research to develop or apply environmentally friendly materials. In particular, research on the replacement of harmful substances generated or contacted during the manufacturing process is being actively conducted, and it is essential to develop more environmentally friendly, high performance, and high functional materials by removing harmful substances.

An object of the present invention is to provide a styrene rubber-based cement composition which is excellent in adhesive strength between rubbers and in which the adhesive strength is maintained for a long time.

Cement composition of the present invention is 5 to 15 parts by weight of liquid isoprene rubber, 30 to 50% by weight of styrene content, 30 to 50% by weight of vinyl polymer solution 30 to 50 parts by weight of styrene butadiene rubber, 30 to 50 parts by weight of styrene 40 to 70 parts by weight of carbon black, 1 to 100 parts of zinc oxide, based on 100 parts by weight of the raw material rubber consisting of 10 to 50 parts by weight of an emulsion-polymerized styrene butadiene rubber having a vinyl content of 30 to 50% by weight, and 5 to 15 parts by weight of butadiene rubber. 5 parts by weight, 1 to 3 parts by weight of stearic acid, 1 to 3 parts by weight of heat resistant antioxidant, 2 to 7 parts by weight of copolymer resin of styrene and α-methylstyrene, 1 to 3 parts by weight of process oil, and 0.1 to 2.0 parts by weight of sulfur Part, characterized in that it comprises 0.5 to 3.0 parts by weight of insoluble sulfur, 0.5 to 2.0 parts by weight of vulcanization accelerator and 50 to 95 parts by weight of a non-aromatic solvent.

The content of the liquid isoprene rubber used in the present invention is preferably used 5 to 15 parts by weight, but less than 5 parts by weight of the aging (adhesion) of the binder is not significantly reduced, if more than 15 parts by weight after vulcanization It is not preferable because the interfacial adhesion is reduced.

The solution-polymerized styrene butadiene rubber (S-SBR) used in the present invention preferably has a styrene content of 30 to 50% by weight and a vinyl content of 30 to 50% by weight. If the styrene content and the vinyl content are out of the range, the physical properties decrease, which is not preferable.

It is preferable to use the solution-polymerized styrene-butadiene rubber 30 to 50 parts by weight, but less than 30 parts by weight, the miscibility and interfacial adhesion strength is not preferable, and if it exceeds 50 parts by weight, green adhesiveness and miscibility is greatly reduced, which is not preferable. not.

The emulsion polymerization styrene butadiene rubber (E-SBR) used in the present invention, the styrene content is 30 to 50% by weight, the vinyl content is preferably 30 to 50% by weight. When the styrene content and the vinyl content are outside the above ranges, the styrene content and the vinyl content do not meet the required physical properties of the reference matrix rubber.

The emulsion-polymerized styrene-butadiene rubber is preferably used in an amount of 10 to 50 parts by weight. If it is less than 10 parts by weight, it is not preferable because of insufficient miscibility.

The butadiene rubber used in the present invention is preferably used in an amount of 5 to 15 parts by weight, but less than 5 parts by weight is not preferable due to lack of dynamic properties and miscibility, and when it exceeds 15 parts by weight, it is not preferable because of miscibility and adhesiveness. not.

The carbon black used in the present invention has an iodine adsorption value of 110 to 130 g / kg, a DBP oil absorption of 122 to 142 ml / 100 g, a nitrogen adsorption specific surface area of 115 to 135 m ² / g, a coloring degree of 110 to 130%, and a particle size distribution map. HP130-based carbon black having a (ΔD50 / M) of 0.95 to 1.55 is preferred, but when the physical properties of the carbon black are outside the above ranges, there is a possibility of a decrease in bonding strength due to a difference in reinforcing effect, and a dispersion effect in solution phase is preferred. Not.

The content of the carbon black is preferably 40 to 70 parts by weight. Outside of the range, the amount of bound rubber is formed, it is difficult to uniformly disperse the solution phase, and the fineness decreases, so the cement solution process is not preferable.

It is preferable to use 2 to 7 parts by weight of the copolymer of the styrene and α-methyl styrene used in the present invention. If it is less than 2 parts by weight, it is not preferable because the green adhesive force is insufficient due to the lack of miscibility and adhesiveness with the rubber component. In addition, exceeding 7 parts by weight affects the cement properties, causes a change in the dynamic viscoelastic properties, and decreases the adhesion of the interface, which is not preferable.

Zinc oxide, stearic acid, heat resistant antioxidants and process oils used in the present invention are used in the above-described content ranges, which are the usual usage ranges used to obtain optimum physical properties. As the heat-resistant anti-aging agent, known ones can be used without limitation, and preferred types thereof include TMDQ (2,2,4-trimethyl-1,2-dihydroquinoline) and IPPD (N-phenyl-N'-isopropyl). -p-phenylenediamine, MBI (2-mercaptobenzimidazole) and TAPDT (2,4,6-tris (N-1,4-dimethylpentyl-p-phenylenediamino) -1,3,5 Triazine), and the like.

The vulcanizing agent and the vulcanization accelerator used in the present invention are not particularly limited in kind. Preferably, sulfur and inert sulfur are used as the vulcanizing agent, and CZ-based vulcanization accelerator may be used as the vulcanizing accelerator. The sulfur content is preferably 0.1 to 2.0 parts by weight, the insoluble sulfur content is 0.5 to 3.0 parts by weight, and the vulcanization accelerator is preferably 0.5 to 2.0 parts by weight. It is not preferable because the rubber interface strength is lowered.

The non-aromatic solvent used in the present invention is preferably a C ₆ ~ C ₈ hydrocarbon-based organic solvent, in particular cyclohexane, n-hexane, or mixtures thereof, or refined heavy naphtha (RHN: Refined Heavy Naphtha) It is preferable to use a solvent.

It is preferable to use the content of the non-aromatic solvent is 50 to 95 parts by weight, the viscosity is less than 50 parts by weight, the coating film is thickened and the drying rate is slowed to form a non-uniform film during application, it is not preferable, If it exceeds 95 parts by weight, the viscosity is low, so it may flow down or the sustained adhesiveness may be lowered, and the interfacial strength may be lowered, which is undesirable.

In the cement composition of the present invention, in addition to the above components, conventional additives added to a general cement composition may be blended in a usual amount of use. Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

Example  And Comparative example

The components, except for sulfur, insoluble sulfur, styrene-α-methylstyrene copolymer, and solvent, were mixed in the first mixer at a temperature of 160 ° C. at 40 rpm for about 3 minutes according to the composition of Table 1, and the mixture was mixed for 4 hours or more. After standing, sulfur and insoluble sulfur were added and blended. At this time, the mixing was performed at a temperature of 105 ° C. for 1 minute. A certain amount of this compound was sufficiently dissolved in a 1: 1 mixed solvent of cyclohexane and n-hexane, then homogenized at a speed of 1000 rpm, then dissolved in a styrene-α-methylstyrene copolymer resin, followed by mixing at a speed of about 600 rpm. In order to improve the uniformity of the solution, a cement composition was prepared by adding DPG, a nonionic surfactant.

Physical properties of the cement compositions of the prepared examples and comparative examples were measured according to ASTM standards, and the results are shown in Table 2 below.

Table 1

                                       (Unit: parts by weight)

Furtherance Comparative example Example Natural Rubber ^{1 )} 100 - Liquid Isoprene Rubber - 10 Solution Polymerized Styrene Butadiene Rubber - 40 Emulsion polymerization styrene butadiene rubber - 40 Butadiene rubber - 10 N330 carbon black 30 - HP130 carbon black - 60 Styrene-α-methylstyrene copolymer resin - 4 Zinc oxide 10 3 Stearic acid 2 2 ^{Heat Resistant Antioxidant 2 )} 3 3 Process oil 2 2 brimstone 2.6 0.9 Insoluble sulfur - 1.8 Vulcanization accelerator ^{3 )} 0.4 1.0 Diphenylguanidine (DPG) - 0.5 Solvent ^{4 )} 45 91

Note 1) SMR 5CV (Malaysia Standard Rubber)

    2) TMDQ (2,2,4-trimethyl-1,2-dihydroquinoline)

       Product name: Kumanox-RD (Kumho Monsanto Co., Ltd. product)

    3) TBBS (t-butyl-2-benzothiazole sulfenamide)

    4) Cyclohexane: n-hexane = 1: 1 mixed solvent

TABLE 2

Test Items Comparative example Example  Rheometer (160 ℃) Tmin (minutes) 11.2 10.4 Tmax (minutes) 24.9 24.3 T40 (minutes) 6.27 6.42 T90 (minutes) 10.55 10.27 EC (minutes) ¹⁾ 11.61 11.30   Tensile Properties Hardness (shore A) 63 64 300% -modulus (kg / ㎠) 117 120 Tensile Strength (kg / ㎠) 260 270 Elongation (%) 530 525 Tear strength 53 59 PAD (kg / ㎠) ²⁾ Early 25.4 36.5 After aging 20.0 31.7 Green adhesive ^{3 )} Early 3.10 3.50 3 days later 2.50 2.65

1) E.C: End cure

2) PAD: Peel adhesion

3) Green adhesiveness means that the larger the value, the better the green adhesiveness. If green adhesiveness is lowered, it may cause process problems due to lack of adhesiveness when molding rubber semi-finished product.

As shown in Table 2, the vulcanization characteristics of the cement composition of Example compared to the vulcanization characteristics of the natural rubber cement composition of the comparative example showed almost the same degree of vulcanization, and there was almost no difference in physical properties even in the tensile properties. However, the comparative example showed a tendency to break at the interface in the strip adhesion test, whereas the example shows a marked improvement in the adhesion at the interface. This is believed to be because the adhesive strength between the cement and the rubber matrix is greatly enhanced when the cement composition of the present invention is used.

The cement composition of the present invention was applied to the actual tire rubber semifinished product (applied to the high styrene rubber compound), and the results of comparing the adhesion behavior of the rubber interface through the evaluation results of the driving using the actual accelerated vehicle (AUTO-CROSS) are shown in Table 3. It was.

TABLE 3

Test Items Comparative example Example Interface state after peeling Interface separation Pure rubber stamp ^{1 )} Mooney viscosity (125 ℃) 52.59 47.87 Observation of interface between rubber layers after exothermic test (after 20,000 repetitions) Partial Interface Verified Interfacial Insignificance Tire auto cross driving result (after 20 times of rapid braking while driving more than 200km at high speed) Partial Interface Verified No interfacial separation

Note) 1) Pure rubber stamping means that the rubber A and rubber B are cemented and crosslinked, and when the bond strength is measured, they are torn from rubber A or B and there is no separation at the interface.

As shown in Table 3, when the cement composition of the present invention is applied, the interface between rubber layers is not separated.

Cement composition of the present invention has been shown to have an effect of preventing the interface separation compared to the conventional natural rubber-based cement composition is excellent in adhesion and green adhesive strength of the rubber compound.

Claims (2)

5-15 parts by weight of liquid isoprene rubber, 30-50% by weight of styrene, 30-50% by weight of vinyl polymer, 30-50 parts by weight of styrene-butadiene rubber, 30-50% by weight of styrene, vinyl content 40 to 70 parts by weight of carbon black, 1 to 5 parts by weight of zinc oxide, 1 stearic acid based on 100 parts by weight of the raw material rubber consisting of 10 to 50 parts by weight of an emulsion-polymerized styrene butadiene rubber of 30 to 50% by weight, and 5 to 15 parts by weight of butadiene rubber. ~ 3 parts by weight, heat resistant antioxidant 1 to 3 parts by weight, copolymer resin of styrene and α-methylstyrene 2 to 7 parts by weight, process oil 1 to 3 parts by weight, sulfur 0.1 to 2.0 parts by weight, insoluble sulfur 0.5 to A cement composition comprising 3.0 parts by weight, 0.5 to 2.0 parts by weight of vulcanization accelerator and 50 to 95 parts by weight of a non-aromatic solvent. The method of claim 1, wherein the heat resistant antioxidant is 2,2,4-trimethyl-1,2-dihydroquinoline, N-phenyl-N'-isopropyl-p-phenylenediamine, 2-mercaptobenzimi Cement composition, characterized in that the doazole or 2,4,6-tris (N-1,4-dimethylpentyl-p-phenylenediamino) -1,3,5-triazine.