KR100315456B1 - Chloroprene rubber composition having good thermal resistance and abrasion resistance - Google Patents

Abstract

The present invention relates to a chloroprene rubber composition, by mixing chloroprene rubber vulcanized with sulfur and chloroprene rubber vulcanized with mercaptan and adding carbon black having an average particle size of 30 to 40 ㎛, heat resistance and mechanical strength The present invention relates to a chloroprene rubber composition having excellent wear resistance.

Description

Chloroprene rubber composition having good thermal resistance and abrasion resistance

The present invention relates to a chloroprene rubber composition, and more particularly, to a chloroprene rubber composition excellent in heat resistance and wear resistance, characterized by using carbon black excellent in wear resistance and reinforcement.

Generally, chloroprene rubber is a synthetic rubber with a long history, and has excellent physical properties such as ozone resistance, heat resistance, and oil resistance, and especially weather resistance. In addition, since it has high polarity of chlorine, the cohesive energy due to intermolecular force is large, and thus oil resistance and solvent resistance are excellent, and thus it has been widely used in many rubber products requiring these properties in combination.

Chloroprene rubber is mostly a chloroprene rubber homopolymer, and has a structure of 80% or more trans-1,4 bond and has a very regular structure, so it is crystallized reversibly and is already crystallized at room temperature, and has the highest density among synthetic rubbers. .

Chloroprene polymers are generally prepared by emulsion polymerization, and the bond amount of trans-1,4 is changed depending on the polymerization temperature. That is, as the polymerization temperature is higher, the amount of trans-1,4 bond is gradually reduced and the crystallinity is lowered.

However, although chloroprene rubber has excellent physical properties as described above, its use has been limited in the field requiring high mechanical strength and high wear resistance due to its weak mechanical strength and poor wear resistance.

In addition, chloroprene has a problem in that weather resistance and water resistance are poor when ZnCl ₂ is released when vulcanized with zinc oxide (ZnO) instead of sulfur.

Therefore, various methods have been tried to improve this.

For example, in order to improve the abrasion resistance of the chloroprene rubber composition, a method of increasing the content of rubber or selecting a polymer having a high molecular weight has been proposed.

However, when the rubber content is increased or when a polymer having a large molecular weight is used, there is a problem in that an increase in product price and workability are deteriorated.

The present invention has been made to solve the problems as described above, to provide a chloroprene rubber composition excellent in mechanical properties without reducing heat resistance.

The present invention to achieve the above object,

a) 40 to 60 parts by weight of chloroprene rubber vulcanized with sulfur;

b) 40 to 60 parts by weight of chloroprene rubber vulcanized with mercaptan; And

c) 35 to 65 parts by weight of carbon black based on 100 parts by weight of the mixture of a) and b).

It provides a chloroprene rubber composition comprising a.

The present invention also provides a chloroprene rubber composition having an average particle diameter of the carbon black of 30 to 40 ㎛.

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

The chloroprene rubber composition used in the present invention is preferably used by mixing 40 to 60 parts by weight of chloroprene rubber vulcanized with sulfur and 40 to 60 parts by weight of chloroprene rubber vulcanized with mercaptan.

Chloroprene rubber vulcanized with sulfur forms a three-dimensional network structure by intermolecular connection in the form of -S-S- and thus has a sulfur bond in the molecular chain, and the terminal of the molecule is a thiuram structure. Although having a structure, since the heat resistance and the permanent compression decrease rate is less than 60 parts by weight of chloroprene rubber vulcanized with sulfur is not preferable because the heat resistance of the chloroprene rubber composition is lowered.

In addition, chloroprene rubber vulcanized with mercaptan (R-SH, where R is an organic functional group) does not contain sulfur bonds in the molecular chain in the molecular structure, so it has excellent heat resistance and compression set, but mechanical strength is low. Since it is low, the use of more than 60 parts by weight of chloroprene rubber vulcanized with mercaptan lowers the mechanical strength is not preferred.

Therefore, in the present invention, it is preferable to mix 40 to 60 parts by weight of chloroprene rubber vulcanized with sulfur and 40 to 60 parts by weight of chloroprene rubber vulcanized with mercaptan, thereby improving all the physical properties to be achieved by the present invention. do.

In addition, it is preferable that the average particle diameter of the carbon black used in the present invention is 30 to 40 µm, and when the average particle diameter is less than 30 µm, it is not preferable because the compounding process is difficult, and the average particle diameter is 40 µm. When exceeding, since the reinforcement property of carbon black is inferior, since the wear resistance improvement of a chloroprene rubber composition cannot be expected, it is not preferable.

The carbon black is preferably used in an amount of 35 to 65 parts by weight based on 100 parts by weight of rubber, and when carbon black is less than 35 parts by weight, improvement of mechanical properties and abrasion resistance cannot be expected. In the case of blending and workability may be inferior, it is not preferable.

In addition, to the chloroprene rubber composition according to the present invention, colorants, foaming agents, flame retardants, softeners and the like can be further added within a range not departing from the object of the invention.

Hereinafter, preferred examples are provided to aid in understanding the invention. However, the following examples are provided to better understand the present invention, and the present invention is not limited to the following examples.

Example 1

40 parts by weight of sulfur-vulcanized chloroprene rubber, 60 parts by weight of chloroprene rubber vulcanized with mercaptan, 45 parts by weight of carbon black having an average particle diameter of 30 to 40 μm, 6 parts by weight of zinc oxide, based on 100 parts by weight of the chloroprene rubber mixture, 5.5 parts by weight of magnesium oxide, 1 part by weight of stearic acid, 5 parts by weight of N2 oil (manufactured by unchanged petrochemical), 3 parts by weight of antioxidant, ethylene thiourea (ETU) -75 0.7 parts by weight and 1 part by weight of tetramethyl thiuram disulfide (TT) were mixed to prepare a rubber composition in an open mill.

Example 2

60 parts by weight of chloroprene rubber vulcanized with sulfur, 40 parts by weight of chloroprene rubber vulcanized with mercaptan, 45 parts by weight of carbon black having an average particle diameter of 30 to 40 μm, 6 parts by weight of zinc oxide, based on 100 parts by weight of the chloroprene rubber mixture, A rubber composition was prepared in an open mill by mixing 5.5 parts by weight of magnesium oxide, 1 part by weight of stearic acid, 5 parts by weight of number 2 oil, 3 parts by weight of an antioxidant, 0.7 parts by weight of ETU-75, and 1 part by weight of TT.

Comparative Example 1 to Comparative Example 5

A rubber composition was prepared by mixing each component in the amounts shown in Table 1 below. Tensile strength and abrasion wear specimens of the prepared rubber composition were measured to measure rubber properties.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Chloroprene rubber vulcanized with mercaptan 60 40 40 40 40 100 Sulfur Vulcanized Chloroprene Rubber 40 60 60 60 60 100 Carbon Black 1 45 45 70 45 45 Carbon Black 2 45 Carbon Black 3 45 Zinc oxide 6 6 6 6 6 6 6 Magnesium oxide 5.5 5.5 5.5 5.5 5.5 5.5 5.5 Stearic acid One One One One One One One Number 2 oil 5 5 5 5 5 5 5 Anti-aging 3 3 3 3 3 3 3 TT One One One One One One One ETU 0.7 0.7 0.7 0.7 0.7 0.7 0.7

Carbon black 1: 30-40 micrometers of average particle diameters

Carbon Black 2: Average Particle Size 70 to 90 µm

Carbon Black 3: Average Particle Size 300 to 500 µm

The chloroprene rubber compositions prepared in Examples 1 and 2 and Comparative Examples 1 to 5 were pressed at an appropriate vulcanization time at 150 ° C. to prepare tensile strength and acron wear specimens, and were left at room temperature and 100 ° C. in a dry oven for 2 weeks. The heat resistance of the rubber was measured.

Tensile strength test for the rubber composition was carried out using a universal tensile tester (Instron 4204) with a KS type No. 3 tensile test specimen at a rate of 500 mm / min, wear resistance test was carried out using an Akron wear tester 4.5 500 kg pre-wear was performed in the state of adding kg and then the average value was measured by measuring the amount of wear three times by 1,000 revolutions.

The measured values are shown in Table 2.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Room temperature Tensile Strength (㎏ / ㎠) 209 228 157 125 176 189 238 Average wear (g) 0.44 0.51 1.11 1.29 1.04 0.45 0.57 100 ℃ dry oven for 2 weeks Tensile Strength (㎏ / ㎠) 206 210 139 89 141 156 176 Average wear (g) 0.73 0.79 1.86 2.14 1.62 0.71 1.08

As shown in Table 2, in the rubber composition of 40 to 60 parts by weight of sulfur-vulcanized chloroprene rubber and 40 to 60 parts by weight of chloroprene rubber vulcanized with mercaptan, 45 parts by weight of carbon black having an average particle diameter of 30 to 40 μm In the used chloroprene rubber compositions of Examples 1 and 2, the tensile strength was 200 kg / cm 2 and the average wear amount was less than 1.0 g. It can be seen that excellent.

However, as a result of using carbon black having an average particle diameter of 70 µm or more, the rubber compositions of Comparative Example 1 and Comparative Example 2 had a mechanical strength of less than 160 kg / cm 2 and a mechanical abrasion of 1.0 g or more. It can be seen that the strength and wear resistance are lower than those of the chloroprene rubber compositions of Examples 1 and 2.

The rubber composition of Comparative Example 4 using 100 parts by weight of chloroprene rubber vulcanized with mercaptan is excellent in wear resistance with an average wear amount of 1.0 g or less, but it can be seen that the mechanical strength is low as the tensile strength is less than 190 kg / cm 2.

In addition, in the rubber composition of Comparative Example 5 using 100 parts by weight of sulfur-vulcanized chloroprene rubber, tensile strength and abrasion resistance at room temperature showed excellent physical properties of 238 kg / cm 2 and 0.57 g, respectively. In the 2-week heat resistance test, the tensile strength was 176 kg / cm 2, and the average wear amount was 1.98 g, indicating that the mechanical strength and the abrasion resistance were poor.

Therefore, the chloroprene rubber composition according to the present invention is used by mixing chloroprene rubber vulcanized with sulfur and chloroprene rubber vulcanized with mercaptan to have excellent heat resistance and mechanical strength by using carbon black having an average particle diameter of 30 to 40 μm. The chloroprene rubber composition excellent in wear resistance can be provided.

Claims (2)

a) 40 to 60 parts by weight of chloroprene rubber vulcanized with sulfur; b) 40 to 60 parts by weight of chloroprene rubber vulcanized with mercaptan; And c) 35 to 65 parts by weight of carbon black based on 100 parts by weight of the mixture of a) and b). Chloroprene rubber composition comprising a. The method of claim 1, Chloroprene rubber composition having an average particle diameter of the carbon black of 30 to 40 ㎛.