KR20050023127A - Thermoplastic Elastomer Composition Having Anti-Abrasion and Excellent Slip Property - Google Patents

Abstract

PURPOSE: Provided is a thermoplastic elastomer composition for producing product under extrusion or drawing process having excellent abrasion-resistance and slip property comprising EPDM rubber together with styrene-ethylene-butadiene copolymer. CONSTITUTION: The composition comprises 50-100 parts by weight of EPDM rubber, 300-500 parts by weight of homo polypropylene, 10-40 parts by weight of filler, 1-10 parts by weight of styrene-ethylene-butadiene copolymer, 5-20 parts by weight of aliphatic amide, 2-10 parts by weight of cross-linking agent and 1-6 parts by weight of cross-linkage activating agent. EPDM rubber is three-member copolymer comprising ethylene and propylene as main components. The homo polypropylene has isotacticity of at least 96 and melt index (230deg.C, 2.16kg) ranging from 2-25g/min.

Description

Thermoplastic Elastomer Composition Having Anti-Abrasion and Excellent Slip Property}

The present invention relates to a thermoplastic elastomer composition having excellent wear resistance and slip resistance. More specifically, styrene-ethylene-butadiene air reduces the size of EPDM rubber by reducing the interfacial tension between EPDM rubber and Homo Polypropylene having a crosslinked structure, thereby increasing the interfacial adhesion. The present invention relates to a thermoplastic elastomer composition having a high wear resistance and a low coefficient of friction and excellent slip resistance by mixing the copolymer, which can be extruded and injected simultaneously with other thermoplastic elastomers.

Conventionally, the surface of the thermoplastic elastomer was coated with polyurethane to realize a low coefficient of friction. However, the polyurethane coating has a problem that it is impossible to achieve a consistently low friction coefficient because of poor wear resistance.

In addition, US Patent No. 6,440,492 discloses a method of coating rubber with crystalline polyolefin powder to realize wear resistance and low coefficient of friction.

In addition, Japanese Patent Application Laid-Open No. 7-346094 discloses a method of blending a polyolefin resin with a thermoplastic elastomer and then a filler such as fatty acid amide and organopolysiloxane, but showing a significant decrease in abrasion resistance and coefficient of friction. It is difficult to lower, and there is a problem of inferior slip.

In order to solve the above problems, the present invention provides a homopolypropylene matrix (PP) by mixing a styrene-ethylene-butadiene copolymer which lowers the interfacial tension and increases the interfacial adhesion between the EPDM rubber having a crosslinked structure and the homopolypropylene. It is an object of the present invention to provide a thermoplastic elastomer composition having excellent slip resistance and improved wear resistance and low coefficient of friction as the particle diameter of the EPDM rubber component having a cross-linked structure in the matrix is reduced and the morphology is improved. .

The above and other objects of the present invention can be achieved by the present invention described below.

The present invention, 50 to 100 parts by weight of Ethylene-Propylene-Dine Monomer rubber to achieve the above object; 300 to 500 parts by weight of homo polypropylene; 10 to 40 parts by weight of the filler; 1 to 10 parts by weight of styrene-ethylene-butadiene copolymer; Aliphatic amide 5 to 20 parts by weight; 2 to 10 parts by weight of a crosslinking agent; And 1 to 6 parts by weight of the crosslinking agent; provides an excellent thermoplastic elastomer composition characterized in that the wear resistance and slip properties.

Hereinafter, the present invention will be described in detail.

Thermoplastic elastomers may be prepared by dynamic crosslinking reaction under high shear stress and heat treatment using a continuous extruder by adding a crosslinking agent and a crosslinking active agent to a composition including EPDM rubber, homo polypropylene and styrene-ethylene-butadiene copolymer. Can be.

The EPDM rubber is a ternary copolymer composed mainly of ethylene and propylene, and is ethylidene-norbonene, dicyclopentadiene and 1,4-hexadiene, which are diene copolymers having unsaturated bonds. (1,4-hexadiene) etc. can be used, It is preferable to use the said ethylidene norbornene copolymer with a high crosslinking speed. The EPDM rubber may be used in the range of 50 to 100 parts by weight in the entire thermoplastic elastomer.

The properties of the homopolypropylene are greatly influenced by molecular weight, molecular weight distribution and stereoregularity. The homo polypropylene is crystalline, isotacticity may be 96 or more, and the melt index (230 ° C., 2.16 kg) may be used in the range of 2 to 25 g / min to increase the crystallinity. It is preferable to use in the range of 11 g / 10min. The test method is measured by using TS T-1238 (ASTM D 1238).

The homo polypropylene may be used in the range of 300 to 500 parts by weight in the entire thermoplastic elastomer.

The filler is used for the purpose of reinforcing and increasing, and may be selected from the group consisting of carbon black, hard coal, talc, silica, mistron vapor, and the like. The filler may be used in the range of 10 to 40 parts by weight in the entire thermoplastic elastomer.

The styrene-ethylene-butadiene copolymer may use a terpolymer, and the styrene content of the styrene-ethylene-butadiene terpolymer may be used in a range of 20 to 50 parts by weight, and used in a range of 30 to 40 parts by weight. It is preferable.

The styrene-ethylene-butadiene copolymer may be used in the range of 1 to 10 parts by weight of the entire thermoplastic elastomer, and is preferably used in the range of 1 to 5 parts by weight.

The styrene-ethylene-butadiene copolymer reduces the interfacial tension between the EPDM rubber and the homo polypropylene to increase the interfacial adhesion, thereby reducing the EPDM rubber size to excellent wear resistance and low A thermoplastic elastomer having a coefficient of friction and excellent slip properties is produced.

The aliphatic amide is used to increase the slip properties of the thermoplastic elastomer according to the present invention, and may be used as the Amoslip of AKZO NOBEL, which is a commercially available oleamide-based liquid tank. have. The aliphatic amide may be used in the range of 5 to 20 parts by weight in the entire thermoplastic elastomer.

The crosslinking agent and the crosslinking agent may be used among a mixture of sulfur and a vulcanization accelerator, a mixture of a phenol resin and a halogen donor, and a mixture of a peroxide and a peroxide activator. As the mixture of the phenol resin and the halogen donor in the crosslinking agent and the crosslinking agent, a mixture of Esp-1045 and tin chloride of Schenctady may be used.

The crosslinking agent may be used in the range of 2 to 10 parts by weight in the entire thermoplastic elastomer. In addition, the crosslinking activator may be used in the range of 1 to 6 parts by weight in the entire thermoplastic elastomer.

In addition, general additives such as stearic acid, process oil, compatibilizer, and antioxidant, which are mainly used in the polymer processing industry, may be further used, and the amount of use may be used within a range that does not significantly affect the crosslinking. That is, the stearic acid may be used in the range of 0.1 to 2 parts by weight in the entire thermoplastic elastomer, and the process oil may be used in the range of 60 to 100 parts by weight in the entire thermoplastic elastomer. In addition, the compatibilizer may be used in the range of 1 to 10 parts by weight of the entire thermoplastic elastomer.

The hardness of the thermoplastic elastomer comprising the composition as described above is in the range of 40 to 60 Shore D, and preferably in the range of 45 to 55 Shore D.

As the kneading apparatus that can be used in the present invention, a banbury mixer, a single screw extruder, a twin screw extruder, or the like can be used, and it is preferable to use a continuous kneading apparatus.

The present invention will be described with reference to the drawings as follows.

1 shows the size of the crosslinked EPDM rubber of a thermoplastic elastomer using a styrene-ethylene-butadiene copolymer according to the present invention, and the size of the crosslinked EPDM rubber is 1 to 3 μm.

Figure 2 shows the size of the crosslinked EPDM rubber of the thermoplastic elastomer not using a styrene-ethylene-butadiene copolymer unlike the present invention, the size of the crosslinked EPDM rubber is 3 to 5㎛.

Therefore, it can be seen that the size of the crosslinked EPDM rubber of the thermoplastic elastomer using the styrene-ethylene-butadiene copolymer according to the present invention is smaller, and the size of the crosslinked EPDM rubber is reduced in roughness on the surface. It can have an excellent friction coefficient, it can be seen that there is an excellent effect of wear resistance and slip resistance.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the examples.

Example 1

100 parts by weight of EPDM rubber was mixed at 80 rpm at a temperature of 180 ° C. for 1 minute in a brabender mixer capable of controlling the temperature by oil circulation, and then 390 parts by weight of homopolypropylene was added and further mixed for 2 minutes. 1.5 parts by weight of stearic acid, 1.8 parts by weight of zinc oxide, 9.0 parts by weight of styrene-ethylene-butadiene copolymer, 10.0 parts by weight of aliphatic amide and 75.0 parts by weight of paraffinic process oil were mixed and mixed for 3 minutes, and then 4.0 parts by weight of phenol resin. After the addition and mixing for 1 minute, 1.0 parts by weight of the crosslinking agent was added, and further mixed for 5 minutes to prepare a final uniform thermoplastic elastomer composition.

Example 2

A final uniform thermoplastic elastomer composition was prepared in the same manner as in Example 1 except that 380 parts by weight of homo polypropylene and 7 parts by weight of styrene-ethylene-butadiene copolymer were applied.

Example 3

A final uniform thermoplastic elastomer composition was prepared in the same manner as in Example 1 except that 370 parts by weight of homo polypropylene and 5 parts by weight of styrene-ethylene-butadiene copolymer were applied.

Example 4

A final uniform thermoplastic elastomer composition was prepared in the same manner as in Example 1 except that 360 parts by weight of homopolypropylene and 3 parts by weight of styrene-ethylene-butadiene copolymer were applied.

Example 5

A final uniform thermoplastic elastomer composition was prepared in the same manner as in Example 1 except that 350 parts by weight of homopolypropylene and 2 parts by weight of styrene-ethylene-butadiene copolymer were applied.

Comparative Example 1

In order to contrast with the thermoplastic elastomer composition of the present invention, the respective physical properties were measured by using Teflon PTFE (Polytetrafluoroethylene) manufactured by Dupont, USA.

Teflon coating paints a fluorine resin, sprays an appropriate amount on the surface like paint, and then heats and calibrates at a constant temperature to form an inert hard coating layer.

Comparative Example 2

In order to compare with the thermoplastic elastomer composition of the present invention, each physical property was measured by using Dow TPU 2355 series 95AE (Thermoplastic polyurethanes).

Comparative Example 3

The final uniform thermoplastic elastomer composition was prepared by mixing in the same manner as in Example 1 except for the styrene-ethylene-butadiene copolymer.

[Test Example 1]

The compositions of Examples 1 to 5 and Comparative Examples 1 to 2 were recovered, and some of them were compression molded at 210 ° C. to prepare test pieces, and some of them were extruded using an extruder into ribbon-shaped sheets to measure physical properties. After fabrication, the physical properties were tested and evaluated.

The physical property measurement results of Examples 1 to 5 and Comparative Examples 1 to 2 are summarized in Table 1 below.

division Shore D Tensile Strength (MPa) Elongation (%) Static friction coefficient Dynamic friction coefficient DIN wear Example 1 52 25.5 480 0.17 0.14 35 Example 2 51 25.1 493 0.18 0.16 38 Example 3 50 23.5 520 0.20 0.16 38 Example 4 49 22.6 550 0.21 0.17 40 Example 5 48 20.6 587 0.21 0.18 42 Comparative Example 1 52 35 320 0.25 0.20 43 Comparative Example 2 52 38.9 450 0.30 0.25 48

Note: 1) Tensile strength and elongation were measured using ATS D-638.

   2) Dynamic and static friction coefficients were measured using the 'Standard Test Method for Static and Dynamic Friction Coefficients of Plastic Films and Sheets' using ATS D-1894.

3) Abrasion resistance measured by 'DIN wear' test using KS M 6518

As can be seen in Table 1, embodiments of the thermoplastic elastomer composition having excellent wear resistance and slip resistance according to the present invention are elongation rate, increase as the content of the homo polypropylene and styrene-ethylene-butadiene copolymer for EPDM rubber Static friction coefficient, dynamic friction coefficient and DIN wear decreased, and tensile strength increased. In addition, the hardness was increased as a result of increasing the content of the homo polypropylene and styrene-ethylene-butadiene copolymer, and the content of the homo polypropylene and styrene-ethylene-butadiene copolymer was adjusted to obtain the desired hardness. It was possible to do. Therefore, it was found that a thermoplastic elastomer composition having various physical properties can be obtained by appropriately adjusting the mixing ratio of IPD rubber, homo polypropylene and styrene-ethylene-butadiene copolymer.

As a result, in the case of DIN wear for wear resistance, it was found that the wear resistance of the thermoplastic elastomer composition was excellent because the DIN wear amount of the embodiments was reduced compared to Comparative Examples 1 and 2, and the static and dynamic coefficients of friction for slip resistance were compared. Compared with 1 and 2 it can be seen that since the static and dynamic coefficients of friction of the embodiments is reduced, the slip properties of the thermoplastic elastomer composition are excellent.

[Test Example 2]

The morphology characteristics of the thermoplastic elastomers of Example 1 and Comparative Example 3 were chopped and then refluxed with a predetermined amount (30 g) for 10 minutes with xylene, followed by evaporation of xylene in a dry oven at 100 ° C. . The sample was observed with an electron microscope (SEM) to measure the size of the crosslinked EPDM rubber. The surface states of the styrene-ethylene-butadiene copolymer used and unused were compared and shown in FIGS. 1 and 2.

1 is a cross-sectional view of the size of the crosslinked IPM rubber of the thermoplastic elastomer using a styrene-ethylene-butadiene copolymer according to the present invention, Figure 2 is a thermoplastic elastomer of the styrene-ethylene-butadiene copolymer is not used unlike the present invention The size of the crosslinked EPDM rubber is shown.

The size of the cross-linked IMPDM rubber using the styrene-ethylene-butadiene copolymer of FIG. 1 was 1 to 3 µm, and the size of the cross-linked IMPDM rubber without the styrene-ethylene-butadiene copolymer of FIG. 2 was 3 to 5 It was found to be μm.

As can be seen in Figures 1 to 2 below, the thermoplastic elastomer using the styrene-ethylene-butadiene copolymer according to the present invention was found to have a smaller size of the crosslinked EPDM rubber. It can be seen that the smaller the roughness on the surface can have an excellent coefficient of friction, and the wear resistance and slip resistance is excellent.

As described above, the thermoplastic elastomer composition having excellent abrasion resistance and slip resistance according to the present invention reduces the interfacial tension between EPDM rubber having a crosslinked structure and Homo Polypropylene to increase interfacial adhesion. It is a useful invention having excellent wear resistance and low coefficient of friction and excellent slip property by mixing styrene-ethylene-butadiene copolymer which reduces EPDM rubber size.

While the invention has been described in detail above with reference to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the scope and spirit of the invention, and such modifications and variations fall within the scope of the appended claims. It is also natural.

1 is a photograph of the size of the crosslinked EPDM rubber of a thermoplastic elastomer using a styrene-ethylene-butadiene copolymer according to the present invention is observed by electron microscopy (SEM).

Figure 2 is a photograph observing the size of the crosslinked EPDM rubber of the thermoplastic elastomer not using a styrene-ethylene-butadiene copolymer unlike the present invention by an electron microscope (SEM).

Claims (10)

50 to 100 parts by weight of EPDM rubber; 300 to 500 parts by weight of homo polypropylene; 10 to 40 parts by weight of the filler; 1 to 10 parts by weight of styrene-ethylene-butadiene copolymer; Aliphatic amide 5 to 20 parts by weight; 2 to 10 parts by weight of a crosslinking agent; And 1 to 6 parts by weight of the crosslinking agent; thermoplastic elastomer composition comprising a. The method of claim 1, The EPDM rubber is a ternary copolymer composed mainly of ethylene and propylene, and is a diene copolymer having an unsaturated bond, as ethylidene-norbonene, dicyclopentadiene, and 1, Thermoplastic elastomer composition, characterized in that 4-hexadiene (1,4-hexadiene). The method of claim 1, Isotacticity of the homopolypropylene (Isotacticity) is 96 or more thermoplastic elastomer composition, characterized in that. The method of claim 1, Melt index (230 ℃, 2.16kg) of the homopolypropylene is a thermoplastic elastomer composition, characterized in that 2 to 25 g / min. The method of claim 1, The filler is a thermoplastic elastomer composition, characterized in that at least one selected from the group consisting of carbon black, hard coal, talc, silica, mistron vapor. The method of claim 1, The styrene-ethylene-butadiene copolymer is a thermoplastic elastomer composition, characterized in that the terpolymer. The method of claim 6, The styrene of the styrene-ethylene-butadiene terpolymer is 20 to 50 parts by weight of the thermoplastic elastomer composition. The method of claim 1, The crosslinking agent and the crosslinking agent are a mixture of sulfur and a vulcanization accelerator, a mixture of a phenol resin and a halogen donor, and a mixture of a peroxide and a peroxide activator. The method of claim 1, The thermoplastic elastomer composition may further comprise 0.1 to 2 parts by weight of stearic acid, 1 to 10 parts by weight of a compatibilizer, and 60 to 100 parts by weight of process oil. The method of claim 1, The thermoplastic elastomer composition has a hardness of 40 to 60 Shore D. The thermoplastic elastomer composition.