JP4430655B2 - Resin composition for cable jacket or air hose having bending resistance and low friction resistance - Google Patents

Description

  The present invention relates to a low friction cable excellent in bending resistance. Specifically, the present invention relates to a cable for an FA device such as an industrial robot in which a working unit such as a robot arm is mounted on a mobile device.

  The present invention also relates to a compressed air hose for driving FA equipment.

  In recent years, FA devices such as industrial robots have rapidly spread, but in many cases, cable / hose support and guide devices are used in devices equipped with moving devices that move the working parts such as robot arms in parallel. . A cable / hose support guide device (hereinafter referred to as a support guide device) that can be deformed following the movement of the action portion is arranged between the action portion mounted on the mobile device and the fixed end on the drive and supply side. It has been guiding a number of cables and air hoses.

  Here, the cable in the support guide device continuously bends and stretches with the movement of the action portion and rubs against the surroundings. The cable is continuously bent and stretched, and friction between the outer surface of the cable, the outer surface of the cable and the outer surface of the air hose, and the outer surface of the cable and the inner surface of the support guide device continues. As a result, if the cable jacket has insufficient bending resistance and surface slipperiness, the cable will be deformed and the coating will be broken by continuous use for a short time. Finally, the conductor breaks.

  As a method for imparting bending resistance to a cable jacket, it is known to use an aramid fiber or a fluorine-based resin as a reinforcing material for a cable jacket as disclosed in, for example, Japanese Patent Laid-Open No. 5-325651.

  However, it is not preferable to use such an expensive resin for general-purpose industrial equipment because it increases costs.

  Although improving only the slipperiness | lubricity of the electric wire coating | covering material surface is shown by patent publication 4-74803, the improvement of bending resistance is not mentioned at all and is not suggested. The invention disclosed in the publication relates to a semi-rigid coated electric wire that does not require bending resistance such as a jumper wire made of a semi-rigid polyvinyl chloride resin, and is used for a cable arranged in the support guide device as described above. Is not applicable.

  On the other hand, in recent years, cables having a cable jacket made of thermoplastic urethane resin and various tubes and hoses made of thermoplastic urethane resin have been used. It is because it is excellent in low temperature flexibility and oil resistance and has good mechanical properties. However, it is not sufficient for applications that require a high degree of bending resistance and surface slip.

  An object of the present invention is to provide a cable that can solve the above problems and is excellent in bending resistance and low friction. That is, in an industrial robot or the like equipped with a mobile device, the cable guided in the support guide device that can be deformed following the movement of the mobile device is prevented from being deformed and torn. In particular, it is intended to provide a cable that significantly suppresses meandering due to deformation of the cable, buckling (bending), and covering breakage that occur when a large number of cables and air hoses are arranged in the support guide device.

  In the resin composition for a bend resistant low friction cable jacket according to claim 1, polyvinyl chloride resin, vinyl chloride / vinyl acetate copolymer resin, ethylene / vinyl chloride copolymer resin, or ethylene / acetic acid The fatty acid amide is 0.2 to 3.0 parts by weight and the liquid plasticizer is 55 to 90 parts by weight with respect to 100 parts by weight of any one of the terpolymer resins obtained by grafting vinyl chloride to the vinyl copolymer. It is characterized by blending.

  The resin composition for a cable jacket or an air hose having a low bending resistance and a low friction according to claim 2 is obtained by blending 0.2 to 3.0 parts by weight of erucylamide with 100 parts by weight of a thermoplastic polyurethane resin. It is characterized by that.

  The resin composition for a cable sheath or an air hose having bending resistance and low friction according to claim 3 has 20 carbon atoms relative to 100 parts by weight of a thermoplastic polyurethane resin whose soft segment is made of polytetramethylene glycol or polypropylene glycol. It is characterized by comprising 0.2 to 3.0 parts by weight of a primary amide of ˜30 fatty acids.

  By using a cable jacket made of a composition comprising a vinyl chloride resin or a copolymer resin of vinyl chloride and vinyl acetate and the like with a relatively large amount of a liquid plasticizer and an appropriate amount of a fatty acid amide, Provides a low-friction cable with excellent properties. In particular, in an FA device in which an action part such as a robot arm is mounted on a mobile device, a cable connected to the action part is arranged in a support guide device that can be deformed following the movement of the action part. The cable that can withstand long-term continuous use is inexpensive.

  Similarly, by using a cable jacket made of a composition obtained by adding 0.2 to 3.0 parts by weight of a fatty acid amide to a thermoplastic urethane resin, a low-friction cable having excellent bending resistance can be obtained. .

  The composition of claim 1 of the present invention uses a polyvinyl chloride resin or a vinyl chloride copolymer resin as the base resin of the composition constituting the cable jacket. This is because vinyl chloride resin is inexpensive, flame retardant, and easy to process.

  As the polyvinyl chloride resin, all ordinary ones can be used, and partially crosslinked ones are also used. Examples of vinyl chloride copolymer resins include vinyl chloride / vinyl acetate copolymer resins, ethylene / vinyl chloride copolymer resins, or ternary copolymer resins obtained by grafting vinyl chloride to ethylene / vinyl acetate copolymers. Are preferably used, but others are possible.

  As the fatty acid amide added to the vinyl chloride resin, erucylamide and oleylamide are particularly preferable. However, other fatty acid amides such as ethylene bisamide, methylol amide and the like can also be used.

  The blending amount of the fatty acid amide is 0.2 to 3.0 parts by weight, preferably 0.4 to 2.0 parts by weight with respect to 100 parts by weight of the vinyl chloride resin or vinyl chloride copolymer resin. When the blending amount of the fatty acid amide is less than 0.2 parts by weight, the bending and low friction resistance of the cable jacket is insufficient, and when it exceeds 3.0 parts by weight, kneading and extrusion for forming the cable jacket from the composition Inferior processability in

  As the liquid plasticizer, liquid plasticizers for various vinyl chloride resins such as DOP (dioctyl phthalate), phthalate ester, trimellitic ester, phosphate ester and fatty acid ester can be used alone or in combination. Can be used. Examples of phthalic acid ester-based compounds include dioctyl phthalate, diethylhexyl phthalate, ditridecyl phthalate, and the like, and trimellitic acid-based compounds include trioctyl trimellitate, tri-n-octyl trimellitate, etc. Examples of fatty acid esters include dioctyl adipate, dioctyl azelate, dioctyl sebacate and the like. Further, tricresyl phosphate can be used as a phosphoric ester-based liquid plasticizer, and those obtained by epoxidizing and stabilizing vegetable oils such as soybean oil can also be used.

  The addition amount of the liquid plasticizer is 55 to 90 parts by weight, preferably 60 to 80 parts by weight with respect to 100 parts by weight of the vinyl chloride resin or vinyl chloride copolymer resin. When the amount of the liquid plasticizer is 55 parts by weight or less, sufficient flexibility cannot be obtained. Therefore, even when the amount of the fatty acid amide is sufficient, sufficient bending resistance cannot be obtained. On the other hand, when the amount of the liquid plasticizer exceeds 90 parts by weight, the cable jacket becomes excessively flexible, and particularly the friction resistance is lowered.

  In the composition of claim 1 of the present invention, in addition to the above basic components, fillers and stabilizers generally used for vinyl chloride resins, flame retardants, lubricants and colorants can be added as appropriate. As the filler, for example, calcium carbonate, aluminum hydroxide, aluminum silicate (calcined clay) and the like can be used, and as the stabilizer, for example, lead-based, calcium-zinc-based, tin-based, and the like can be used.

  The compositions of Claims 2 and 3 of the present invention are compositions for constituting a cable jacket or an air hose, and are obtained by adding an appropriate amount of a specific fatty acid amide to a thermoplastic urethane resin.

  The thermoplastic urethane resin is composed of a soft segment derived from a long-chain diol component and a hard segment derived from a short-chain diol component. When heated and melted, the entire fluid flows uniformly, but after molding, the soft segment is in the rubber state to the softened state, and the hard segment is in the glass state to form a physical cross-linked portion (portion that has the same effect as vulcanization) .

  As the thermoplastic urethane resin, the long-chain diol is polytetramethylene glycol (PTMG) or polypropylene glycol (PPG), and the long-chain diol is polycaprolactone (PCL) or polycarbonate polyester (PCP). A polyester diol or a special diol such as polybutadiene diol can also be used. The polytetramethylene glycol (PTMG) type is preferred from the balance between physical properties, durability and price.

  The fatty acid amide added to the thermoplastic urethane resin is preferably a higher fatty acid amide having 20 to 30 carbon atoms, more preferably such a primary amide of a monoene unsaturated fatty acid, and particularly preferably erucyl amide. . The fatty acid primary amide added to the polytetramethylene glycol (PTMG) type or polypropylene glycol type thermoplastic urethane resin needs to have 20 to 30 carbon atoms (Claim 3).

  The compounding amount of the fatty acid amide is 0.2 to 3.0 parts by weight, preferably 0.3 to 2.5 parts by weight with respect to 100 parts by weight of the thermoplastic urethane resin. When the blending amount of the fatty acid amide is less than 0.2 parts by weight, the cable has insufficient bending resistance and low frictional resistance. Inferior in workability.

  A cable jacket is formed from the composition according to claim 1, 2 or 3 by extrusion molding or the like.

  An FA hose driving air hose is molded in the same manner from the thermoplastic urethane resin composition according to claim 2 or 3. The air hose, for example, guides compressed air for bending and stretching the robot arm, and is housed together with a cable in the following support guide device and is subjected to repeated bending and friction in exactly the same manner as the cable jacket of the cable. Therefore, in the thermoplastic urethane resin-based composition having pressure resistance, those used for the cable jacket can be used as they are for the air hose.

  Evaluation of the durability performance of the cable relating to the bending resistance and low friction resistance of the cable jacket was performed as follows.

  The cable used for the evaluation of the durability performance is a twisted vinyl insulation vinyl sheath cable (1) including four pairs of conductor wires as shown in the sectional view of FIG. Two conductors (3) having a cross-sectional area of 0.2 square millimeters are each covered with an insulator (4) and twisted together, and four pairs of electric wires are bundled from such a pair to form a cylindrical cable. is there. Here, an electromagnetic shielding layer is provided in the cross section of the cable jacket (2).

  A durability performance test apparatus and test conditions will be described with reference to FIGS.

  As shown in FIG. 2, the movable end (6) is movably arranged along the horizontal rail (5), and the fixed end (7) is provided on the base surface (9) below the rail (5). It has been. Between the moving end (6) and the fixed end (7), a caterpillar chain-shaped support guide device (8) is arranged. When the moving end (6) comes directly above the fixed end (7), the support guide device (8) has an elongated, generally U-shaped shape that lies on its side. Along with the movement, it moves like a part of a caterpillar chain running left and right on the base surface (9). Here, TKP0320-2B (Curved radius of curvature of caterpillar curved portion (R) 37 mm) manufactured by Enomoto Chain Co., Ltd. was used as the support guide device.

  Six cables (1) were attached to such a device. The cable (1) is gently wired in two steps in three in the fixed end (7) and the support guide device (8) (FIG. 3), and is clamped by a jig only at the moving end (6). The movement of the cable in the length direction is restricted.

  The cable was tested for bending resistance by repeatedly reciprocating the moving end (6) on the rail (5). Here, the moving stroke of the moving end on the rail was set to 100 cm, and the moving speed was set to 100 m / min. Each cable continues to bend and stretch, and continues to receive friction with the adjacent cable and the inner surface of the support guide device. When the bending is repeated, a meandering portion is first generated in the cable, and then the cable is bent just before the cable is broken. This state was determined to be buckling. The number of reciprocations of the moving end until buckling occurred was regarded as the number of bending resistances, and the measurement was repeated three times to represent the approximate range of measured values.

(Examples 1-3)
A polyvinyl chloride resin TK-2500LS (average polymerization degree 2250) manufactured by Shin-Etsu Chemical Co., Ltd. was used as the base resin of the composition constituting the cable jacket (2). 60, 80, and 70 parts by weight of DOP were added as liquid plasticizers to 100 parts by weight of the base resin. As fatty acid amide, 0.5 part by weight of Armoslip E (registered trademark), an Elsilamide product manufactured by Lion Akzo, was added. Further, a composition in which 6 parts by weight of tribasic lead sulfate and 1 part by weight of lead stearate as a stabilizer and 50 parts by weight of calcium carbonate as a filler was added was used.

Table 1 shows the results of durability performance evaluation expressed by the number of bending resistances together with a list of compositions. In each of Examples 1 to 3, very excellent durability performance of 50,000 to 60,000 was obtained. Moreover, as shown in the lower end of Table 1, there was no problem in workability when forming the cable jacket.

(Examples 4 to 5)
In Examples 4 to 5, the amount of fatty acid amide added was 0.25 parts by weight.

  In Example 4, the same conditions as in Example 3 were used except that the amount of fatty acid amide added was reduced to 0.25 parts by weight and the amount of calcium carbonate added was increased to 60 parts by weight.

  In Example 5, 0.25 parts by weight of Armoslip CP-P (registered trademark), an oleylamide product manufactured by Lion Akzo, was used as the fatty acid amide in place of Armoslip E (registered trademark), which is an erucylamide product. The conditions were the same as in Examples 3 to 4, except that the amount of calcium carbonate added was 40 parts by weight.

  As shown in Table 1, even if either erucylamide or oleylamide is used, when the amount of fatty acid amide is 0.25 parts by weight, the number of flexing is 30,000 to 40,000, and practically sufficient durability performance is provided. A cable was obtained. However, the durability performance of the cable was slightly lower than in Examples 1 to 3 to which 0.5 part by weight was added.

(Example 6)
The conditions were exactly the same as in Example 3 except that the amount of Armoslip E (Elsylamide) added was increased to 2.8 parts by weight. As shown in Table 1, the measured number of flexing resistances was the same as in Example 3 with 0.5 parts by weight added, and no further effect was observed due to the increase in the amount added. On the other hand, no problem was found in the workability shown at the lower end of Table 1.

(Comparative Examples 1-3)
In the composition constituting the cable jacket (2), other compositions were the same as those in Example 3, and the addition amount of fatty acid amide was 0, 0.1 and 0.15 parts by weight. Here, only in Comparative Example 2, armor slip CP-P (oleylamide) was used instead of armor slip E (erucylamide). The results are shown in Table 2. In Comparative Example 1 with an addition amount of 0 and Comparative Example 2 with an addition amount of 0.15 parts by weight, the number of flexing resistances is only 20 or less, and even in Comparative Example 3 with an addition amount of 0.15 parts by weight, the number of flexing resistances is only 40 or less. There wasn't. From these results, it is known that the effect of addition is hardly seen when the amount of fatty acid amide added is 0.15 parts by weight or less. In light of the results of Examples 4 to 5, it is known that the durability performance of the cable changes dramatically between 0.15 parts by weight and 0.25 parts by weight.

(Comparative Example 4)
The conditions were the same as in Examples 3 and 6, except that the amount of fatty acid amide added was 3.5 parts by weight. The number of bending resistances was 50,000 to 60,000 as in Examples 1 to 3 and 6, but there was difficulty in workability in kneading and extrusion, and it was difficult to form a cable jacket industrially. Accompanied by. That is, even if the amount of the fatty acid amide was increased to about 3.5 parts by weight, the effect of improving the durability performance was not seen, and the processability was only impaired.

(Comparative Examples 5-6)
The amount of DOP added was 45 parts by weight and 100 parts by weight, and the other compositions were the same as in Examples 1-3. As shown in Table 2, all of the durability performance was insufficient.

  In Comparative Example 5 in which the amount of DOP added is too small, the flexibility of the cable is low, so that the cable is difficult to bend, and the curvature of the support guide device (8) is increased by increasing the curvature R of the cable. In addition to hindering the movement of (6), in actual use conditions, it may cause contact or collision with other members adjacent to the support guide device, causing damage to the member and the support guide device. . Therefore, it was determined that the curved portion of the support guide device (8) was unusable when the bulge of the curved portion was clearly observed. When the reciprocation of the moving end (6) was continued, buckling occurred at 20,000 to 30,000. Since the cable has low flexibility and poor bendability, friction in the support guide device is increased, and it is considered that the durability performance was insufficient.

  On the other hand, when the amount of DOP added is excessive, the number of flexing resistances was 5,000 to 10,000, which was significantly lower than that of the example. It is considered that the durability performance represented by the number of bending resistances was insufficient because the cable was excessively flexible and low friction was not obtained.

  The above results show that the effects of the present invention can be obtained only by a synergistic effect of an appropriate amount of DOP and an appropriate amount of fatty acid amide.

(Examples 7 to 9)
A vinyl chloride copolymer resin was used in place of the polyvinyl chloride resin as the base resin of the composition constituting the cable jacket (2), and other conditions were the same as in Examples 1 to 3. The following three types of resins were used as vinyl chloride copolymer resins. Rislon E-2800 (average polymerization degree 2750) manufactured by Tosoh Corporation which is an ethylene-vinyl chloride copolymer resin, and Nipolit MH manufactured by Chisso Corporation which is a VA-PVC resin which is a vinyl acetate-vinyl chloride copolymer resin. (Average polymerization degree 1500) and ZEST GR5F (average polymerization degree 1400) manufactured by Shin-Daiichi PVC Co., Ltd., which is a ternary copolymer resin obtained by grafting vinyl chloride onto an ethylene-vinyl acetate copolymer.

As shown in Table 3, even when these copolymer resins were used, the same results as those obtained using the polyvinyl chloride resin were obtained.

(Examples 10 to 12)
As a resin composition constituting the cable jacket (2), Armor slip E (registered trademark) is 0.3 parts by weight, 0.5 part by weight and Kuraray Co., Ltd. thermoplastic urethane resin Clamiron U-9185, respectively. What added 2.5 weight part was used.

Table 4 shows the results of durability performance evaluation expressed by the number of bending resistances. In Example 10, very excellent durability performance of 30,000 to 40,000 and in Examples 11 to 12 of 50,000 to 60,000 were obtained. Moreover, as shown in the lower end of Table 4, there was no problem in workability when forming the cable jacket.

(Comparative Examples 7-8)
Comparative Examples 7 and 8 were the same as Examples 10 to 12 except that the addition amount of Armoslip E (registered trademark) was 0 parts by weight and 0.1 parts by weight, respectively. In both cases, the number of flexing resistances is extremely low as 1 to 5, and it is known that the durability performance cannot be obtained when the fatty acid amide is not added or the added amount is insufficient even if it is added.

(Comparative Examples 9 to 10)
In Comparative Examples 9 and 10, 0.5 parts by weight and 1.0 parts by weight of Armoslip CP-P were added in place of Armoslip E, and the others were the same as in Examples 10-12. In the cables of Comparative Examples 9 and 10, no fatty acid amide bleed was observed on the surface. That is, the armor slip CP-P was too high in compatibility with the thermoplastic urethane resin and was included in the resin, and no exudation to the resin surface was observed.

  Both erucylamide (Armoslip E) and oleylamide (Armoslip CP-P) differ only in that they are the primary amides of monoene unsaturated fatty acids having 22 and 18 carbon atoms, respectively. Therefore, it is known from the comparison with Examples 10 to 12 that in this type of fatty acid amide, the performance of imparting bending resistance to the thermoplastic urethane resin changes critically around 20 carbon atoms.

(Comparative Example 11)
In Comparative Example 11, the amount of Armoslip E (registered trademark) added was 3.5 parts by weight. The number of bending resistances was 50,000 to 60,000 as in Examples 11 to 12, but there were difficulties in workability in kneading and extrusion, and it was difficult to form a cable jacket industrially. . That is, even if the amount of the fatty acid amide was increased to about 3.5 parts by weight, the effect of improving the durability performance was not seen, and the processability was impaired.

(Example 13)
A tube was formed from the same composition as in Example 11 with the same diameter and thickness as the cable jacket (2). The thermoplastic urethane resin is used as a pressure-resistant hose, and originally has sufficient pressure resistance against compressed air and its reliability. When the inside of the tube was kept at a positive pressure of about 1 atm with compressed air, the bending resistance test was performed in the same manner as in the case of the cable (2), and the number of bending resistances was 50,000 times or more. .

It is sectional drawing of the cable used for durability performance evaluation. It is a schematic diagram of a durability performance test apparatus. The cable arrangement at the fixed end of the durability test apparatus will be described.

Explanation of symbols

1 pair twisted vinyl insulated vinyl sheath cable 2 cable jacket 3 conductor
4 Insulator 6 Moving end 7 Fixed end 8 Support guide device

Claims (3)

Following the movement of the robot arm or other action part mounted on the mobile device, it is guided into the deformable support guide device (8) and continues to bend and stretch, and the adjacent cable (1) and the support guide device ( 8) A resin composition for the cable jacket (2) for the cable (1) that continues to receive friction with the inner surface,
A resin composition for a bend-resistant, low-friction cable jacket, comprising 0.2 to 3.0 parts by weight of erucylamide based on 100 parts by weight of a thermoplastic polyurethane resin. 2. The resistance to resistance according to claim 1 , wherein 0.3 to 2.5 parts by weight of erucylamide is blended with 100 parts by weight of a thermoplastic polyurethane resin whose soft segment is made of polytetramethylene glycol or polypropylene glycol. A resin composition for a bent low-friction cable jacket. The bending-resistant low friction according to claim 1 or 2, wherein the cable (1) is supported and guided by a caterpillar chain-type support guide device (8) having a U-shaped curved portion. Resin composition for flexible cable jackets.

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