Method of producing sliding material for weather strips

Abstract

PP, an EPDM prior to crosslinking, and PE particles are fed into a twin screw extruder and melt-kneaded so that the EPDM is dynamically crosslinked, whereby a sliding material for weather strips formed of an olefin-based TPV in which the PE particles are dispersed is produced. The amount of the PE particles blended is 10 parts by mass to 90 parts by mass with respect to 100 parts by mass of the total amount of the PP and the EPDM. It is preferable that the PE particles have an average particle diameter of 30 m to 200 m before the feeding, and are micronized by the melt kneading to have an average particle diameter of 10 m to 50 m in the produced sliding material for weather strips.

Claims

1. A method of producing a sliding material for weather strips, the sliding material formed of an olefin-based TPV in which PE particles are dispersed, the method comprising: feeding PP, an EPDM prior to crosslinking, and PE particles into a twin screw extruder, and melt-kneading the PP, the EPDM, and the PE particles to dynamically crosslink the EPDM, wherein the PE particles have an average particle diameter of 30 m to 200 m before the feeding, and are micronized by the melt-kneading to have an average particle diameter of 10 m to 50 m in a produced sliding material for weather strips.

2. The method of producing a sliding material for weather strips according to claim 1, wherein the PE particles are blended in an amount of 10 parts by mass to 90 parts by mass with respect to 100 parts by mass of the total amount of the PP and the EPDM.

3. The method of producing a sliding material for weather strips according to claim 1 wherein a material for the PE particles is an ultra-high molecular weight PE.

4. The method of producing a sliding material for weather strips according to claim 1, wherein, in the sliding material for weather strips, 30 parts by mass or less of a silicone compound is additionally blended with respect to 100 parts by mass of the total amount of the PP and the EPDM.

5. The method of producing a sliding material for weather strips according to claim 1, wherein, in the sliding material for weather strips, 30 parts by mass or less of a silicone compound is additionally blended with respect to 100 parts by mass of the total amount of the PP and the EPDM, and wherein the silicone compound is fed into the twin screw extruder and kneaded together with the PP, the EPDM prior to crosslinking, and the PE particles.

6. The method of producing a sliding material for weather strips according to claim 1, wherein, in the sliding material for weather strips, 30 parts by mass or less of a silicone compound is additionally blended with respect to 100 parts by mass of the total amount of the PP and the EPDM, and wherein the olefin-based TPV in which PE particles are dispersed obtained using the twin screw extruder and the silicone compound are newly fed into a twin screw extruder and melt-kneaded.

7. A method of producing a sliding material for weather strips, the sliding material formed of an olefin-based TPV in which PE particles are dispersed, the method comprising: feeding PP, an EPDM prior to crosslinking, and PE particles into a twin screw extruder, and melt-kneading the PP, the EPDM, and the PE particles to dynamically crosslink the EPDM, wherein the PE particles are blended in an amount of 10 parts by mass to 90 parts by mass with respect to 100 parts by mass of the total amount of the PP and the EPDM, and wherein a material for the PE particles is an ultra-high molecular weight PE.

8. The method of producing a sliding material for weather strips according to claim 7 wherein the PE particles have an average particle diameter of 30 m to 200 m before the feeding, and are micronized by the melt-kneading to have an average particle diameter of 10 m to 50 m in a produced sliding material for weather strips.

9. The method of producing a sliding material for weather strips according to claim 7, wherein, in the sliding material for weather strips, 30 parts by mass or less of a silicone compound is additionally blended with respect to 100 parts by mass of the total amount of the PP and the EPDM.

10. The method of producing a sliding material for weather strips according to claim 7, wherein, in the sliding material for weather strips, 30 parts by mass or less of a silicone compound is additionally blended with respect to 100 parts by mass of the total amount of the PP and the EPDM, and wherein the silicone compound is fed into the twin screw extruder and kneaded together with the PP, the EPDM prior to crosslinking, and the PE particles.

11. The method of producing a sliding material for weather strips according to claim 7, wherein, in the sliding material for weather strips, 30 parts by mass or less of a silicone compound is additionally blended with respect to 100 parts by mass of the total amount of the PP and the EPDM, and wherein the olefin-based TPV in which PE particles are dispersed obtained using the twin screw extruder and the silicone compound are newly fed into a twin screw extruder and melt-kneaded.

12. A method of producing a sliding material for weather strips, the sliding material formed of an olefin-based TPV in which PE particles are dispersed, the method comprising: feeding PP, an EPDM prior to crosslinking, and PE particles into a twin screw extruder, and melt-kneading the PP, the EPDM, and the PE particles to dynamically crosslink the EPDM, wherein the PE particles are blended in an amount of 10 parts by mass to 90 parts by mass with respect to 100 parts by mass of the total amount of the PP and the EPDM, and wherein, in the sliding material for weather strips, 30 parts by mass or less of a silicone compound is additionally blended with respect to 100 parts by mass of the total amount of the PP and the EPDM.

13. The method of producing a sliding material for weather strips according to claim 12 wherein the PE particles have an average particle diameter of 30 m to 200 m before the feeding, and are micronized by the melt-kneading to have an average particle diameter of 10 m to 50 m in a produced sliding material for weather strips.

14. The method of producing a sliding material for weather strips according to claim 12 wherein the silicone compound is fed into the twin screw extruder and kneaded together with the PP, the EPDM prior to crosslinking, and the PE particles.

15. The method of producing a sliding material for weather strips according to claim 12 wherein the olefin-based TPV in which PE particles are dispersed obtained using the twin screw extruder and the silicone compound are newly fed into a twin screw extruder and melt-kneaded.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1A to 1C illustrate a method of producing a sliding material for weather strips according to Examples, wherein FIG. 1A is a schematic diagram illustrating that PP, an EPDM prior to crosslinking, and PE particles are fed into a twin screw extruder to perform melt-mixing, FIG. 1B is a schematic diagram illustrating that olefin-based TPV pellets in which PE particles are dispersed obtained in FIG. 1A and a silicone compound are newly fed into a twin screw extruder to perform melt-kneading, and FIG. 1C is a schematic view illustrating the structure of a sliding material for weather strips obtained in FIG. 1B;

(2) FIG. 2A1 is a side view of the state of an abrasion test, FIG. 2A2 is a sectional view of a test piece after the abrasion test, FIG. 2B1 is a side view of the state of sliding resistance measurement, and FIG. 2B2 is a plan view of the state of the sliding resistance measurement;

(3) FIG. 3A is a sectional view of a glass run formed by applying a sliding material for weather strips of Examples to a portion, making sliding contact with glass, of a weather strip, and FIG. 3B is a sectional view of an inner weather strip and an outer weather strip formed by applying a sliding material for weather strips of Examples to a portion, making sliding contact with glass, of a weather strip; and

(4) FIGS. 4A and 4B illustrate a method of producing a sliding material for weather strips according to Conventional Example, wherein FIG. 4A is a schematic diagram illustrating that an olefin-based TPV after crosslinking and PE particles are fed into a twin screw extruder to perform melt-mixing, and FIG. 4B is a schematic view illustrating the structure of a sliding material for weather strips obtained in FIG. 4A.

MODES FOR CARRYING OUT THE INVENTION

(5) PP, an EPDM prior to crosslinking, and PE particles are fed into a twin screw extruder and melt-kneaded so that the EPDM is dynamically crosslinked, whereby a sliding material for weather strips formed of an olefin-based TPV in which the PE particles are dispersed is produced. The amount of the PE particles blended is 10 parts by mass to 90 parts by mass with respect to 100 parts by mass of the total amount of the PP and the EPDM. It is preferable that the PE particles have an average particle diameter of 30 m to 200 m before the feeding, and are micronized by the melt kneading to have an average particle diameter of 10 m to 50 m in the produced sliding material for weather strips. A material for the PE particles is preferably an ultra-high molecular weight PE.

(6) In the sliding material for weather strips, 30 parts by mass or less of a silicone compound may be additionally blended with respect to 100 parts by mass of the total amount of the PP and the EPDM. The silicone compound may be fed into the twin screw extruder and kneaded together with the PP, the EPDM prior to crosslinking, and the PE particles. Alternatively, the silicone compound and the olefin-based TPV in which PE particles are dispersed obtained using the twin screw extruder may be newly fed into a twin screw extruder and melt-kneaded.

EXAMPLES

(7) Olefin-based TPVs (sliding materials for weather strips) of Examples 1 to 7 and Comparative Example 1 of the respective formulations shown in the following Table 1 were produced. The values of the formulations represent the amounts in parts by mass of other materials blended with respect to 100 parts by mass of the total amount of PP and an EPDM.

(8) TABLE-US-00001 TABLE 1 Comparative Example 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Material PP 64 64 64 64 64 64 64 64 (parts by EPDM 36 36 36 36 36 36 36 36 mass) PE particles 0 10 10 40 40 70 86 102 Compatibilizing 10 10 10 10 10 10 10 10 agent Carbon black 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 MB Crosslinking 4 4 4 4 4 4 4 4 agent Antioxidant 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 Silicone 5.9 6.4 30 7.9 30 30 10.2 11.1 compound Total Amount 123.1 133.6 157.2 165.1 187.2 217.2 213.4 230.3 Amount of 4.8 4.8 19.1 4.8 16 14 4.8 4.8 Silicone compound relative to total amount (% by mass) Normal Tensile strength 26.0 good 19.1 good 17.1 good 14.0 good 15.8 good 16.8 good 14.0 good 15.1 good Physical [Mpa] Properties Elongation [%] 560 good 480 good 500 good 340 good 410 good 370 good 160 good 120 good Static friction 0.45 poor 0.32 good 0.36 good 0.24 good 0.34 good 0.30 good 0.27 good 0.28 good coefficient [] Dynamic friction 0.19 good 0.15 good 0.13 good 0.14 good 0.09 good 0.10 good 0.14 good 0.15 good coefficient [] Sliding 18.2 poor 10.0 good 8.0 good 3.7 good 3.5 good 3.2 good 3.8 good 2.9 good resistance [N] Amount of wear 0.07 good 0.04 good 0.04 good 0.08 good 0.08 good 0.08 good 0.07 good 0.108 fair by glass [mm]

(9) Here, the details of each of the materials areas follows.

(10) PP: block PP, trade name NOVATEC-PP EC7, manufactured by Japan Polypropylene Corporation

(11) EPDM: trade name EP98, manufactured by JSR Corporation

(12) PE particles: UHMWPE particles, trade name HI-ZEX MILLION 240S (average molecular weight: approximately 2,000,000, average particle diameter: approximately 120 m), manufactured by Mitsui Chemicals, Inc.

(13) Compatibilizing agent: trade name TAFMER 7080, manufactured by Mitsui Chemicals, Inc.

(14) Carbon black: carbon black masterbatch (MB), trade name MFP-CB45L, manufactured by MITSUFUKU INDUSTRY CO., LTD.

(15) Crosslinking agent: phenol resin, trade name TACKIROL 250I, manufactured by TAOKA CHEMICAL COMPANY, LIMITED

(16) Antioxidant: hindered phenol-based antioxidant, trade name IRGANOX1010, manufactured by BASF

(17) Silicone compound: pellet type silicone, trade name BY27-001, manufactured by Dow Corning Toray Co., Ltd.

(18) Through the following two steps, the olefin-based TPVs of Examples 1 to 7 and Comparative Example 1 were produced.

(19) (1) Step of Producing an Olefin-Based TPV in which PE Particles are Dispersed

(20) As illustrated in FIG. 1A, PP and an EPDM prior to crosslinking were fed together with a compatibilizing agent, carbon black, a crosslinking agent, and an antioxidant into a first hopper 11 arranged at a base end of a twin screw extruder 10, and PE particles were fed into a second hopper 12 (arranged in the first half portion of the screw length of the twin screw extruder) adjacent to the first hopper 11. During passing through the twin screw extruder 10, the PP, the EPDM prior to crosslinking, and the PE particles were melt-kneaded by shearing by the rotation of twin screws so that the EPDM was dynamically crosslinked, whereby an olefin-based TPV 1 in which the PE particles are dispersed was extruded. Then, this olefin-based TPV 1 was pelletized.

(21) Note that all of these materials may be fed into the first hopper 11 together.

(22) (2) Step of Producing the Olefin-Based TPV Further Containing a Silicone Compound

(23) As illustrated in FIG. 1B, the pellets of the olefin-based TPV 1 obtained using the twin screw extruder 10 were newly fed into a first hopper 21 arranged at a base end of a twin screw extruder 20, and a silicone compound was fed into a second hopper 22 adjacent to the first hopper 21, and these materials were kneaded and an olefin-based TPV 2 containing a silicone compound was extruded.

(24) Note that all of these materials may be fed into the first hopper 21 together.

(25) FIG. 1C is an enlarged schematic view of the structure of the produced olefin-based TPV 2 of Examples 1 to 7. The olefin-based TPV 2 of Examples 1 to 7 had a sea-island structure in which EPDM 4 serving as a domain (island phase) was dispersed in PP 3 serving as a matrix (sea phase), and furthermore, PE particles 5 were dispersed in the olefin-based TPV 2. Compared to the above-described Conventional Example illustrated in FIG. 4B, both the EPDM 4 and the PE particles 5 had better dispersibility. The PE particles 5 had an average particle diameter of approximately 120 m before the feeding, but, were micronized by the melt kneading to have an average particle diameter of approximately 50 m and be uniform in diameter in the thus-produced olefin-based TPV 2.

(26) The normal physical properties of each of the olefin-based TPVs of Examples 1 to 7 and Comparative Example 1 were tested and measured, and evaluated as follows, and shown in Table 1 above.

(27) 1. Tensile Strength and Elongation

(28) In accordance with JIS K6251, a tensile test was carried out at normal temperature to measure tensile strength and elongation (elongation at break). A tensile strength of 6.0 MPa or higher was evaluated as good, and a tensile strength of lower than 6.0 MPa was evaluated as poor. An elongation of 70% or higher was evaluated as good, and an elongation of lower than 70% was evaluated as poor.

(29) 2. Static Friction Coefficient, Dynamic Friction Coefficient

(30) In accordance with JIS K7125, static and dynamic friction coefficients were calculated from loads at the time of movement at 100 mm/min. A static friction coefficient of 0.4 or smaller was evaluated as good, and a static friction coefficient of larger than 0.4 was evaluated as poor. A dynamic friction coefficient of 0.2 or smaller was evaluated as good, and a dynamic friction coefficient of larger than 0.2 was evaluated as poor.

(31) 3. Sliding Resistance

(32) A test piece 2a molded of the olefin-based TPV 2 and having a width of 5 mm, a length of 160 mm, and a thickness of 2 mm was produced, and the test piece 2a was attached onto a holder 15 and set in a testing machine, as illustrated in FIGS. 2A1 and 2A2. A glass abrader plate 16 having a length of 30 mm in the sliding direction was placed on the test piece 2a, and a load of 10 N was applied thereon, and the surface of the test piece 2a was reciprocally slid in the length direction at a sliding velocity of 150 mm/sec. A load in the horizontal direction was measured at the time of the 50,000th reciprocal sliding cycle, and the measured load was regarded as a sliding resistance value. A sliding resistance of 10 N or smaller was evaluated as good, and a sliding resistance of larger than 10 N was evaluated as poor.

(33) 4. Amount of Wear by Glass

(34) A test piece 2b molded of the olefin-based TPV 2 and having a width of 20 mm, a length of 160 mm, and a thickness of 2 mm was produced, and the test piece 2b was attached onto a holder 17 and set in a testing machine, as illustrated in FIG. 2B1. A glass abrader plate 18 whose bottom surface has a width of 50 mm and a length of 20 mm in the sliding direction (with R =10 mm) was placed on the test piece 2b, and a load of 30 N was applied thereon, and the surface of the test piece 2b was reciprocally slid in the length direction at a sliding velocity of 60 sliding cycles/min. As illustrated in FIG. 2B2, the amount of wear (mm) of the test piece 2b was measured after 10,000 reciprocal sliding cycles. An amount of wear of 0.10 mm or less was evaluated as good, an amount of wear of more than 0.10 mm and not more than 0.11 mm was evaluated as fair, and an amount of wear of more than 0.11 mm was evaluated as poor.

(35) Each of the olefin-based TPVs 2 of Examples 1 to 7 may be applied as a sliding material for weather strips, for example, to a portion, making contact with glass 40, of a glass run 31 as illustrated in FIG. 3A, or of an inner weather strip 32 or an outer weather strip 33 as illustrated in FIG. 3B.

(36) Note that the present invention is not limited to Examples above, and suitable modifications may be embodied within the scope not deviating from the gist of the invention.

(37) (1) Although a silicone compound was kneaded in the second step in Examples, a silicone compound may be fed into the twin screw extruder 10 in the first step and kneaded together with the PP, the EPDM prior to crosslinking, and the PE particles.

REFERENCE SIGNS LIST

(38) 1 Olefin-based TPV 2 Olefin-based TPV containing a silicone compound 2a Test piece 2b Test piece 3 PP 4 EPDM 5 PE particle 10 Twin screw extruder 11 First hopper 12 Second hopper 15 Holder 16 Glass abrader plate 17 Holder 18 Glass abrader plate 20 Twin screw extruder 21 First hopper 22 Second hopper 31 Glass run 32 Inner weather strip 33 Outer weather strip