FABRIC, AND CABLE COVER FOR ROBOT ARM

Abstract

For providing a fabric that has a low frictional property and can exhibit long-term tribological properties even when the fabric is subjected to a high-speed frictional force under a high load, there is provided a fabric according to the present invention is a fabric in which a composite yarn of fluororesin fibers A and fibers B other than fluororesin fibers is used for at least one of a warp yarn and a weft yarn, and the fabric is characterized in that a mass ratio α of the fluororesin fibers A in the composite yarn is 5 to 70%, and a ratio of the area ratio X of the fluororesin fibers in a fabric surface to a mass ratio Y of the fluororesin fibers in the fabric is 1 or more and 5 or less. This fabric can be usefully used for a cable cover for a robot arm.

Claims

1. A fabric wherein a composite yarn of fluororesin fibers A and fibers B other than fluororesin fibers is used for at least one of a warp yarn and a weft yarn, a mass ratio α of the fluororesin fibers A in the composite yarn is 5 to 70%, and a ratio X/Y of an area ratio X of the fluororesin fibers A in a fabric surface to a mass ratio Y of the fluororesin fibers A in the fabric is 1 or more and 5 or less.

2. The fabric according to claim 1, wherein the composite yarn is used for either the warp yarn or the weft yarn, and the fibers B are used as either the weft yarn or the warp yarn orthogonal to the composite yarn.

3. The fabric according to claim 1, wherein the area ratio X is 10% or more and 60% or less.

4. The fabric according to claim 1, wherein the composite yarn is a doubled and twisted yarn obtained by doubling and twisting the fluororesin fibers A and the fibers B other than fluororesin fiber.

5. The fabric according to claim 4, wherein the fibers B constituting the doubled and twisted yarn is a twisted yarn.

6. The fabric according to claim 1, wherein the fluororesin fibers A are made from a polytetrafluoroethylene resin.

7. The fabric according to claim 1, wherein the fibers B are fibers that are 7 cN/dtex or more in tensile strength.

8. The fabric according to claim 7, wherein the fibers B are fibers that are 15 to 50 cN/dtex in tensile strength.

9. The fabric according to claim 1, wherein the fibers B are fibers that have a heat resistance temperature of 280° C. or higher.

10. The fabric according to claim 1, wherein the fibers B are fibers that are 450 to 800 cN/dtex in tensile modulus of elasticity.

11. The fabric according to claim 1, wherein the fibers B are organic fibers.

12. The fabric according to claim 1, wherein the fibers B are fibers selected from liquid crystal polyester fibers, para-aramid fibers, and polyparaphenylene benzobisoxazole fibers.

13. A robot arm cable cover comprising, in at least a part thereof, the fabric according to claim 1.

Description

EXAMPLES

[0057] Hereinafter, examples of the present invention will be described together with comparative examples.

[0058] Methods of measuring various characteristics in the present embodiment are as follows.

[0059] (1) Fineness

[0060] The fabric was disaggregated, and the fineness of the disaggregated yarn was measured in accordance with the 8.3.B method (simplified method) of JIS L1013: 2010 “Testing methods for man-made filament yarns”. If the disaggregated yarn fails to secure the amount of yarn required for the measurement method mentioned above, however, the result of carrying out the test with the maximum length that can be secured and the number of trials is used as a substitute.

[0061] (2) Tensile Strength of Fiber

[0062] The fabric was disaggregated, and the fracture strength of the disaggregated yarn was measured in accordance with 8.5 of JIS L1013: 2010 “Testing methods for man-made filament yarns”. If the disaggregated yarn fails to secure the amount of yarn required for the measurement method mentioned above, however, the result of carrying out the test with the maximum length that can be secured and the number of trials is used as a substitute.

[0063] (3) Elongation of Fiber

[0064] The fabric was disaggregated, and the elongation (elongation percentage) of the disaggregated yarn was measured in accordance with 8.5 of JIS L1013: 2010 “Testing methods for man-made filament yarns”. If the disaggregated yarn fails to secure the amount of yarn required for the measurement method mentioned above, however, the result of carrying out the test with the maximum length that can be secured and the number of trials is used as a substitute.

[0065] (4) Tensile Modulus of Elasticity

[0066] In the measurement (3), the tensile modulus of elasticity was calculated from the elastic modulus at the elongation of 0.5% (average slope from the elongation of 0.45% to the elongation of 0.55%).

[0067] (5) Mass Ratio α of Fluororesin Fibers a in Composite Yarn

[0068] The fabric was cut into a size of 200 mm×200 mm, and the warp yarn and the weft yarn were then disaggregated to obtain disaggregated yarns. For each of the disaggregated warp yarns and the disaggregated weft yarns, five composite yarns were randomly selected from the disaggregated yarns obtained, and disaggregated into fluororesin fibers A and the other fibers, and the mass of each was measured. The mass ratio α of the fluororesin fibers A in the composite yarn was calculated from the following calculation formula with W for the mass sum of the five composite yarns and W.sub.F for the mass sum of the fluororesin fibers A of the five composite yarns.

α=W.sub.F/W×100[%]

[0069] If the disaggregated yarn fails to secure the amount of yarn required for the measurement method mentioned above, however, the result of carrying out the test with the maximum length that can be secured and the number of trials is used as a substitute.

[0070] (6) Weave Density

[0071] In accordance with 8.6.1 of JIS L1096: 2010 “Testing methods for woven and knitted fabrics”, a sample was placed on a flat table with unnatural creases and tension removed, the number of warp yarns and weft yarns was counted in a 50-mm space at different locations, and the average values of the warp yarns and the weft yarns were calculated per unit length.

[0072] (7) Area Ratio X of Fluororesin Fibers A in Fabric Surface

[0073] The fabric was imaged at a magnification of 50 times with a microscope “VHX-2000” manufactured by KEYENCE CORPORATION, and the area ratio of the fluororesin fibers A was calculated from the calculation formula below, with the imaged area defined as S.sub.tot and the area occupied by the fluororesin fibers A in the imaged area as S.sub.A. If X differs between the front surface and the back surface, however, the larger value of X is employed as a representative value.

Area Ratio X of Fluororesin Fiber A=S.sub.A/S.sub.tot×100[%]

[0074] The imaged area S.sub.tot and the area S.sub.A occupied by the fluororesin fibers A were calculated with the use of image analyzing software “WinROOF2015” manufactured by MITANI CORPORATION.

[0075] (8) Mass Ratio Y of Fluororesin Fibers a in Fabric

[0076] The fabric was cut into a size of 200 mm×200 mm, the warp yarn and the weft yarn were then disaggregated, the total mass W of the disaggregated yarns was measured. Subsequently, only composite yarns were selected from the disaggregated yarns, and the total mass W.sub.1 of the composite yarns in the fabric was measured. Subsequently, fluororesin fibers present independently in the fabric, not as any composite yarn, were sorted out, and the total mass W.sub.2 thereof was measured. The mass ratio Y of the fluororesin fibers A in the fabric was calculated from the following formula.

Y=(W.sub.1×α/100+W.sub.2)/W×100[%]

If the disaggregated yarn fails to secure the amount of yarn required for the measurement method mentioned above, however, the result of carrying out the test with the maximum length that can be secured and the number of trials is used as a substitute.

[0077] (9) Number of Twists

[0078] The fabric was disaggregated, and the number of twists of the disaggregated yarn was measured in accordance with 8.13. 1 of JIS L 1013: 2010 “Testing methods for man-made filament yarns”.

[0079] If the disaggregated yarn fails to secure the amount of yarn required for the measurement method mentioned above, however, the result of the test carried out with the maximum length that can be secured and the number of trials can be used as a substitute.

[0080] (10) Kinetic Friction Coefficient

[0081] The kinetic friction coefficient was measured by the ring abrasion test indicated below.

[0082] In accordance with the Method A of JIS K7218: 1986 “Testing methods for sliding wear resistance of plastics”, the woven fabrics were sampled with a length of 30 mm and a width of 30 mm, placed on a thick SUS plate with the same size about 3-mm, and fixed to a sample holder.

[0083] The mating material used is made of S45C, and has a hollow cylindrical ring shape of 25.6 mm in outer diameter, 20 mm in inner diameter and 15 mm in length. The surface of the ring was polished with a sandpaper to the adjusted surface roughness of Ra=0.8 μm±0.1. For the measurement of the roughness, a roughness tester (“SJ-201” from Mitutoyo Corporation) was used.

[0084] With the use of, as a ring abrasion tester, “MODEL: EFM-III-EN” manufactured by A & D Company, Limited, a test was performed at a friction load of 20 MPa and a friction speed of 400 mm/second to measure the sliding torque, and the average value was calculated from friction coefficients to fractures. Because the static friction coefficient was included immediately after the start of sliding, the average value for the friction coefficients from 1 second after the start of sliding (sliding distance: 0.4 m) to fractures was calculated as a kinetic friction coefficient.

[0085] The kinetic friction coefficient of smaller than 0.055 was regarded as A, the kinetic friction coefficient of 0.055 or more and 0.060 or less was regarded as B, the kinetic friction coefficient of larger than 0.060 and 0.065 or less was regarded as C, and the kinetic friction coefficient of larger than 0.065 was regarded as D.

[0086] (11) Sliding Durability Distance

[0087] In the ring abrasion test mentioned above, the sliding was continued until the fabric was fractured, and the fabric that was not fractured even after sliding of 60 m was regarded as A, the fabric fractured at 50 m or more and less than 60 m was regarded as B, the fabric fractured at 40 m or more and less than 50 m was regarded as C, the fabric fractured at 25 m or more and less than 40 m was regarded as D, and the fabric fractured at a sliding distance of less than 25 m was regarded as E.

Example 1

[0088] A PTFE fiber (“TOYOFLON” (registered trademark) from Toray Industries, Inc.) of 880 dtex in total fineness, 120 filaments in number of single yarns, and 33 t/m in number of twists and a liquid crystal polyester fiber (“SIVERAS” (registered trademark) from Toray Industries, Inc.) of 850 dtex in total fineness, 144 filaments in number of single yarns, and 33 t/m in number of twists were doubled and twisted for 167 t/m in number of twists to obtain a composite yarn as a doubled and twisted yarn, and a 3/1 twill fabric was produced by a loom with the use of the doubled and twisted yarn as the warp yarn, and a liquid crystal polyester fiber of 1700 dtex in total fineness and 288 filaments in number of single yarns (“SIVERAS” (registered trademark) from Toray Industries, Inc.) as the weft yarn. Thereafter, the fabric was refined in a refining tank at 80° C. and thermally set at 180° C.

Example 2

[0089] A fabric was obtained in accordance with the same procedure as in Example 1 except that the composite yarn used in Example 1 was used for the warp yarn and the weft yarn.

Comparative Example 1

[0090] A fabric was obtained in accordance with the same procedure as in Example 1 except that a PTFE fiber (“TOYOFLON” (registered trademark) from Toray Industries, Inc.) of 1760 dtex in total fineness and 240 filaments in number of single yarns was used as the weft yarn.

Example 3

[0091] After doubling and twisting a liquid crystal polyester fiber (“SIVERAS” (registered trademark) from Toray Industries, Inc.) of 425 dtex in total fineness and 72 filaments in number of single yarns and a PTFE fiber (“TOYOFLON” (registered trademark) from Toray Industries, Inc.) of 880 dtex in total fineness and 120 filaments in number of single yarns, the liquid crystal polyester fiber of 425 dtex in total fineness and 72 filaments in number of single yarns was further doubled and twisted into the doubled and twisted yarn for 167 t/m in number of twists to obtain a doubled and twisted yarn. A 3/1 twill fabric was produced by a loom with the use of the doubled and twisted yarn as the warp yarn, and a liquid crystal polyester fiber of 1700 dtex in total fineness and 288 filaments in number of single yarns (“SIVERAS” (registered trademark) from Toray Industries, Inc.) as the weft yarn. Thereafter, the fabric was refined in a refining tank at 80° C. and thermally set at 180° C.

Example 4

[0092] After doubling and twisting a liquid crystal polyester fiber of 850 dtex in total fineness and 144 filaments in number of single yarns (“SIVERAS” (registered trademark) from Toray Industries, Inc.) and a PTFE fiber (“TOYOFLON” (registered trademark) from Toray Industries, Inc.) of 440 dtex in total fineness and 60 filaments in number of single yarns, the PTFE fiber (“TOYOFLON” (registered trademark) from Toray Industries, Inc.) of 440 dtex in total fineness and 60 filaments in number of single yarns was further doubled and twisted into the doubled and twisted yarn for 167 t/m in number of twists to obtain a doubled and twisted yarn. A 3/1 twill fabric was produced by a loom with the use of the doubled and twisted yarn as the warp yarn, and a liquid crystal polyester fiber of 1700 dtex in total fineness and 288 filaments in number of single yarns (“SIVERAS” (registered trademark) from Toray Industries, Inc.) as the weft yarn. Thereafter, the fabric was refined in a refining tank at 80° C. and thermally set at 180° C.

Example 5

[0093] A fabric was obtained in accordance with the same procedure as in Example 1 except that the fiber B before doubling and twisting was 0 t/m in number of twists.

Example 6

[0094] A PTFE fiber (“TOYOFLON” (registered trademark) from Toray Industries, Inc.) of 440 dtex in total fineness, 60 filaments in number of single yarns, and 33 t/m in number of twists and a liquid crystal polyester fiber (“SIVERAS” (registered trademark) from Toray Industries, Inc.) of 1275 dtex in total fineness, 216 filaments in number of single yarns, and 33 t/m in number of twists were doubled and twisted for 167 t/m in number of twists to obtain a doubled and twisted yarn, and a 3/1 twill fabric was produced by a loom with the use of the doubled and twisted yarn as the warp yarn, and a liquid crystal polyester fiber of 1700 dtex in total fineness and 288 filaments in number of single yarns (“SIVERAS” (registered trademark) from Toray Industries, Inc.) as the weft yarn. Thereafter, the fabric was refined in a refining tank at 80° C. and thermally set at 180° C.

Example 7

[0095] A fabric was obtained in accordance with the same procedure as in Example 6 except that the composite yarn used in Example 6 was used for the warp yarn and the weft yarn.

Comparative Example 2

[0096] A fabric was obtained in accordance with the same procedure as in Example 6 except that the warp yarn used in Example 6 was used for the weft yarn, whereas the weft yarn used in Example 6 was used for the warp yarn.

Example 8

[0097] A PTFE fiber (“TOYOFLON” (registered trademark) from Toray Industries, Inc.) of 880 dtex in total fineness, 120 filaments in number of single yarns, and 33 t/m in number of twists and a polyparaphenylene terephthalamide fiber of 850 dtex in total fineness, 144 filaments in number of single yarns, and 33 t/m in number of twists (“KEVLAR” (registered trademark) from DU PONT-TORAY CO., LTD.) were doubled and twisted for 167 t/m in number of twists to obtain a doubled and twisted yarn, and a 3/1 twill fabric was produced by a loom with the use of the doubled and twisted yarn as the warp yarn, and a polyparaphenylene terephthalamide fiber of 1700 dtex in total fineness and 288 filaments in number of single yarns (“KEVLAR” (registered trademark) from DU PONT-TORAY CO., LTD.) as the weft yarn. Thereafter, the fabric was refined in a refining tank at 80° C. and thermally set at 180° C.

Example 9

[0098] A PTFE fiber (“TOYOFLON” (registered trademark) from Toray Industries, Inc.) of 880 dtex in total fineness, 120 filaments in number of single yarns, and 33 t/m in number of twists and a polyester fiber (“TETORON”, polyethylene terephthalate fiber from Toray Industries, Inc.) of 850 dtex in total fineness, 144 filaments in number of single yarns, and 33 t/m in number of twists were doubled and twisted for 167 t/m in number of twists to obtain a doubled and twisted yarn, and a 3/1 twill fabric was produced by a loom with the use of the doubled and twisted yarn as the warp yarn, and a polyester fiber of 1700 dtex in total fineness and 288 filaments in number of single yarns (“TETORON”, polyethylene terephthalate fiber from Toray Industries, Inc.) as the weft yarn. Thereafter, the fabric was refined in a refining tank at 80° C. and thermally set at 180° C.

Example 10

[0099] A PTFE fiber (“TOYOFLON” (registered trademark) from Toray Industries, Inc.) of 880 dtex in total fineness, 120 filaments in number of single yarns, and 33 t/m in number of twists and a polyphenylene sulfide fiber (“TORCON” (registered trademark) from Toray Industries, Inc.) of 850 dtex in total fineness, 144 filaments in number of single yarns, and 33 t/m in number of twists were doubled and twisted for 167 t/m in number of twists to obtain a doubled and twisted yarn, and a 3/1 twill fabric was produced by a loom with the use of the doubled and twisted yarn as the warp yarn, and a polyphenylene sulfide fiber (“TORCON” (registered trademark) from Toray Industries, Inc.) of 1700 dtex in total fineness and 288 filaments in number of single yarns as the weft yarn. Thereafter, the fabric was refined in a refining tank at 80° C. and thermally set at 180° C.

Comparative Example 3

[0100] A PTFE fiber (“TOYOFLON” (registered trademark) from Toray Industries, Inc.) of 440 dtex in total fineness, 60 filaments in number of single yarns, and 33 t/m in number of twists and a polyester fiber (“TETORON” (registered trademark), polyethylene terephthalate fiber from Toray Industries, Inc.) of 44 dtex in total fineness and 18 filaments in number of single yarns were doubled and twisted for 210 t/m in number of twists to obtain a doubled and twisted yarn, and a five-harness satin fabric was produced by a loom with the use of the doubled and twisted yarn as the warp yarn, and a polyester fiber of 26 s/2 (454 dtex) in total fineness “TETORON” (registered trademark), polyethylene terephthalate fiber from Toray Industries, Inc.) as the weft yarn. Thereafter, the fabric was refined in a refining tank at 80° C. and thermally set at 180° C.

Comparative Example 4

[0101] A PTFE fiber (“TOYOFLON” (registered trademark) from Toray Industries, Inc.) of 2660 dtex in total fineness, 360 filaments in number of single yarns, and 33 t/m in number of twists and a carbon fiber of 1980 dtex in total fineness, 3000 filaments in number of single yarns, and 33 t/m in number of twists (“TORAYCA” (registered trademark) from Toray Industries, Inc.) were doubled and twisted for 167 t/m in number of twists to obtain a doubled and twisted yarn, and a 2/2 twill fabric was produced by a loom with the use of the doubled and twisted yarn as the warp yarn and the weft yarn. Thereafter, the fabric was refined in a refining tank at 80° C. and thermally set at 180° C.

[0102] For the fabrics described in Examples and Comparative Examples, Tables 1 and 2 summarize the results of evaluating the configuration of the composite yarn, the fabric configuration, the kinetic friction coefficient, and the sliding durability distance.

TABLE-US-00001 TABLE 1 Comparative Example 1 Example 2 Example 1 Example 3 Example 4 Example 5 Configuration Combined method — Doubling and Doubling and Doubling and Doubling and Doubling and Doubling and of composite twisting twisting twisting twisting twisting twisting yarn Mass ratio α of % 51% 51% 51% 51% 51% 51% fluororesin fibers A in composite yarn Fluororesin Fineness dtex 880 880 880 880 440 × 2 880 fiber A Fiber B Fiber type — Liquid Liquid Liquid Liquid Liquid Liquid crystal crystal crystal crystal crystal crystal polyester polyester polyester polyester polyester polyester fiber fiber fiber fiber fiber fiber (425T × 2) Fineness dtex 850 850 850 850 850 850 Tensile cN/dtex 19 19 1 9 19 19 19 strength Tensile cN/dtex 690 690 690 690 690 690 modulus of elasticity Elongation % 5.0 5.0 5.0 5.0 5.0 5.0 Number of t/m 33 33 33 0 33 0 twists Twist t/m .Math. dtex.sup.0.5 962 962 962 0 962 0 coefficient Fabric Weave structure — 3/1 twill 3/1 twill 3/1 twill 3/1 twill 3/1 twill 3/1 twill configuration Yarn used Warp yarn — Composite Composite Composite Composite Composite Composite yarn yarn yarn yarn yarn yarn Weft yarn — Liquid Composite PTFE fiber Liquid Liquid Liquid crystal yarn 1760T-240 crystal crystal crystal polyester polyester polyester polyester fiber fiber fiber fiber 1700T-288F 1700T-288F 1700T-288F 1700T-288F Weave Warp yarn Number of 54 54 54 54 54 54 density yarns/2.54 cm Weft yarn Number of 33 33 33 33 33 33 yarns/2.54 cm Area ratio X of % 45 51 63 32 52 38 fluororesin fibers A in fabric surface Mass ratio Y of % 32 51 70 32 32 32 fluororesin fibers A in fabric X/Y — 1.41 1.00 0.90 1.00 1.63 1.19 Properties Kinetic friction A A A B A A coefficient Sliding durability — A B 0 B B B distance

TABLE-US-00002 TABLE 2-1 Comparative Example 6 Example 7 Example 2 Example 8 Example 9 Example 10 Configuration Combined method — Doubling and Doubling and Doubling and Doubling and Doubling and Doubling and of composite twisting twisting twisting twisting twisting twisting yarn Mass ratio α of % 26% 26% 26% 51% 51% 51% fluororesin fibers A in composite yarn Fluororesin Fineness dtex 440 440 440 880 880 880 fiber A Fiber B Fiber type — Liquid Liquid Liquid Liquid Liquid Liquid crystal crystal crystal crystal crystal crystal polyester polyester polyester polyester polyester polyester fiber fiber fiber fiber fiber fiber Fineness dtex 1275 1275 1275 850 850 850 Tensile cN/dtex 19 19 1 9 16 8 4 strength Tensile cN/dtex 690 690 690 490 115 40 modulus of elasticity Elongation % 5.0 5.0 5.0 5.5 13.0 15.0 Number of t/m 33 33 33 0 33 0 twists Twist t/m .Math. dtex.sup.0.5 1178 1178 1178 962 962 979 coefficient Fabric Weave structure — 3/1 twill 3/1 twill 3/1 twill 3/1 twill 3/1 twill 3/1 twill configuration Yarn used Warp yarn — Composite Composite Liquid Composite Composite Composite yarn yarn crystal yarn yarn yarn polyester fiber 1700T-288F Weft yarn — Liquid Composite Composite Poly-p- Polyester Polyphenylene crystal yarn yarn phenylene fiber sulfide polyester terephtalamide 1670T-200F fiber fiber fiber 1760T-400F 1700T-288F 850T-144F Weave Warp yarn Number of 54 54 54 54 54 54 density yarns/2.54 cm Weft yarn Number of 33 33 33 33 33 33 yarns/2.54 cm Area ratio X of % 17 34 5 45 45 45 fluororesin fibers A in fabric surface Mass ratio Y of % 15 26 10 32 32 32 fluororesin fibers A in fabric X/Y — 1.13 1.31 0.50 1.41 1.41 1.41 Properties Kinetic friction C A D A A A coefficient Sliding durability — C B E A B C distance

TABLE-US-00003 TABLE 2-2 Comparative Comparat ive Example 3 Example 4 Configuration Combined method — Doubling and Doubling and of composite yarn twisting twisting Mass ratio α of % 91% 57% fluororesin fibers A in composite yarn Fluororesin Fineness dtex 440 2660 fiber A Fiber B Fiber type — Polyester Carbon fiber fiber 44T-18F Fineness dtex 44 1980 Tensile cN/dtex 4 18 strength Tensile cN/dtex 90 1300 modulus of elasticity Elongation % 40.0 1.0 Number of t/m 0 33 twists Twist t/m-dtex.sup.0.5 0 1468 coefficient Fabric Weave structure — five-layered 2/2 twill configuration satin Yarn used Warp yarn — Composite Composite yarn yarn Weft yarn — Polyester Composite fiber yarn 26s/2 Weave Warp yarn Number of 50 8 density yarns/2.54 cm Weft yarn Number of 68 8 yarns/2.54 cm Area ratio X of % 69 51 fluororesin fibers A in fabric surface Mass ratio Y of % 40 57 fluororesin fibers A in fabric X/Y — 1.72 0.90 Properties Kinetic friction A A coefficient Sliding durability — E D distance