JPH0577498B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a tube molded from a vinyl chloride resin composition having heat deformation resistance and high impact resilience. <Prior Art> In general, rubber is mainly used for applications requiring heat deformation resistance and high impact resilience. The reason for this is that it has heat deformation resistance and high impact resilience, which are characteristics of rubber. However, tubes made of rubber require a vulcanization process, which increases the number of man-hours, and the material cannot be recycled. In order to overcome the drawbacks of these rubbers, soft vinyl chloride resin and thermoplastic elastomer resin are used in some parts of the tube, but because they are thermoplastic resins, they have low heat deformation resistance and creep resistance. Due to its poor performance, its range of use was limited. <Problems to be Solved by the Invention> In view of the above circumstances, the present inventors have developed a material that has heat deformation resistance and high impact resilience similar to rubber, but has processability similar to that of general thermoplastic resins. As a result of extensive research, we found that a vinyl chloride resin containing polyvinyl chloride gel that is insoluble in tetrahydrofuran (hereinafter referred to as partially crosslinked vinyl chloride resin) and a copolyester resin is used as a blend. When molded from the above-mentioned vinyl chloride resin composition, the tube has heat deformation resistance and high impact resilience close to those of rubber, yet can be molded in the same manner as general thermoplastic resins. This surprising fact was discovered and the present invention was completed. An object of the present invention is to provide a tube molded from a vinyl chloride resin composition that has heat deformation resistance and high impact resilience close to those of rubber, but also has moldability similar to that of general thermoplastic resins. be. <Means for Solving the Problems> That is, the present invention involves adding butane to terephthalic acid to 100 parts by weight of a vinyl chloride resin consisting of 8 to 90% by weight of polyvinyl chloride gel insoluble in tetrahydrofuran and the remainder being soluble in tetrahydrofuran. Diols and poly(tetramethylene oxide)
This tube is made of a vinyl chloride resin having heat deformation resistance and high impact resilience and is made of 10 to 200 parts by weight of a copolyester resin obtained by copolymerizing glycol and 25 to 300 parts by weight of a plasticizer. Depending on the general shape of the tube, the main molding method is extrusion molding, but short special shapes can also be molded by injection molding, blow molding, or press molding. A feature of the tube of the present invention is that a copolyester resin is blended with a partially crosslinked vinyl chloride resin in the resin of the composition. This makes it possible to manufacture tubes with heat deformation resistance and high impact resilience using the same molding method as that used for thermoplastic resins. Although the crosslinked portion in the resin component is not specified, from the viewpoints of heat deformation resistance, high impact resilience, and processability, it is appropriate to range from 8% to 90% by weight. The copolyester resin used in the present invention is obtained by copolymerizing terephthalic acid with butanediol and poly(tetramethylene oxide) glycol, and has a composition of PBT (polybutylene terephthalate) as a hard segment and polyester as a soft segment. It is a polyester resin consisting of terephthalic acid ester of (tetramethylene oxide) glycol. Examples of these include the product name Hytrel manufactured by DuPont Toray. Regarding the number of added parts of copolyester resin, 10
If it is less than 200 parts by weight, it is not effective at all, and if it exceeds 200 parts by weight, it is undesirable because it tends to adhere to the kneading machine, resulting in poor workability and high cost. A particularly desirable range is 30 parts by weight or more and 90 parts by weight or less, which exhibits good impact resilience and processability. In the composition of the present invention, the plasticizer is added to impart rubber elasticity to the obtained molded article and to improve impact resilience, and the amount added varies depending on the intended use of the molded article. However, if the amount of plasticizer is too small, high-temperature melting and high-pressure molding will be required, making processing difficult, and the resulting tube will be brittle and have poor appearance. On the other hand, if the amount of plasticizer is too large, the plasticizer will boil out of the resulting tube, causing many problems in processability and practicality such as stickiness, which is not preferable. Examples of such plasticizers include alkyl esters of aromatic polybasic acids such as dibutyl phthalate, dioctyl phthalate, and butylbenzyl phthalate; alkyl esters of aliphatic polybasic acids such as dioctyl adipate, dioctyl azelate, and dioctyl sepacate; Examples include alkyl esters of phosphoric acid such as tricresyl phosphate, polyesters, and the like. The vinyl chloride resin composition used for the tube of the present invention can be used as it is, but if necessary, it may be blended with other thermoplastic resins, rubber, heat stabilizers, fillers, pigments, processing aids, etc. used.
Other thermoplastic resins include general vinyl chloride resin, ethylene vinyl acetate copolymer, ethylene vinyl chloride copolymer, urethane vinyl chloride copolymer,
Chlorinated polyethylene, ABS resin, AS resin, urethane resin, acrylic resin, etc. are used, and as the rubber, NBR, CR, etc. are used. The partially crosslinked vinyl chloride resin composition used in the tube of the present invention can be granulated and molded by the same process as conventional vinyl chloride resins. That is, it is mixed with a plasticizer, a stabilizer, etc. using a mixer such as a super mixer or a blender, and then kneaded and granulated using a Banbury, roll, extruder, or the like. Of course, even in the form of a mixed powder, there is no difference in molding process from conventional vinyl chloride resins.
Granulated pellets can be made into tubes by injection molding, extrusion molding, blow molding, and press molding in the same way as general vinyl chloride resins, and the moldability is also good like general vinyl chloride resins. However, the resulting tube can exhibit superior heat deformation resistance and impact resilience compared to general vinyl chloride resins. Example 1 100 parts by weight of a vinyl chloride polymer (UX-C, manufactured by Sumitomo Chemical Industries, Ltd.) with a gel content of 20% and an average degree of polymerization of the soluble portion in tetrahydrofuran of 5000, 90 parts by weight of dioctyl phthalate, and a barium zinc stabilizer (ADEKA・Manufactured by Argus, AP-539) 3 parts by weight, and melting point 162℃
and a copolyester resin having Shore D hardness (ASTM) 40 (Hytrel 4057, manufactured by Toray Dupont) were added, and the mixture was kneaded with a Banbury mixer to form pellets. Press sheets were made from the pellets and evaluated for thermal deformation, rebound resilience, and workability.

[Table] As is clear from the results, products using 10 to 200 parts by weight of copolyester resin have good impact resilience, processability, and heat deformation resistance, especially 30 to 90 parts by weight.
Good results were obtained within the range of parts by weight. Example 2 The compositions of experiment numbers 1 and 5 used in Example 1 were
A molded product with an outer diameter of 12 mmφ and an iron core of 6 mmφ in the center was extruded using a 50 mm extruder using a cross die. In order to examine the heat deformation resistance of this tube-shaped molded product, it was cut to a length of 100 mm, left horizontally in an oven at 160°C, a load of 1 kg was applied to the 100 mm length for 1 hour, and then taken out to room temperature. The degree of deformation of the molded product after the load was removed was confirmed. The results are shown in Table 2.

[Table] <Effects of the Invention> The tube of the present invention has good moldability similar to ordinary vinyl chloride resin tubes, and also has properties similar to rubber in terms of heat deformation resistance and high impact resilience. Used for automobiles, especially for covering iron wires such as cable conduits, piping tubes in engine rooms, home appliances, protective cover tubes for electric wires, construction, food, etc., and internal parts for transporting liquids, gases, and solids. is also used.

Claims (1)

[Claims] 1 100 parts by weight of a vinyl chloride resin consisting of 8 to 90% by weight of polyvinyl chloride gel insoluble in tetrahydrofuran and the remainder soluble in tetrahydrofuran, copolymerized butanediol and poly(tetramethylene oxide) glycol with terephthalic acid. A tube made of a vinyl chloride resin having heat deformation resistance and high impact resilience, comprising 10 to 200 parts by weight of a copolyester resin obtained by the above process and 25 to 300 parts by weight of a plasticizer.