JPH0212981B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyester tubular body with excellent sliding properties and mechanical properties. Thermoplastic polyesters, represented by polybutylene terephthalate and polyethylene terephthalate, have excellent mechanical properties, heat resistance, and chemical resistance, and have been widely used as injection molding materials for machinery and electrical parts. Now, they are being applied to functional tubular bodies such as pipes, tubes, and wire coverings by extrusion molding. However, tubular bodies made of thermoplastic polyester have insufficient surface smoothness, resulting in poor sliding properties during use, which not only causes significant wear but also cracks on the surface, leading to destruction of the tubular body. have. On the other hand, as a method of imparting surface smoothness to ordinary thermoplastic polyester molded products, polyolefin, polyfluorinated ethylene, etc.
A method of molding a composition to which molybdenum disulfide, graphite, etc. are added (for example, JP-A-50-55653
Publication No. 50-55657 and Japanese Patent Application Laid-open No. 1972-55657
-66548, etc.), but the tubular bodies formed by molding the above compositions not only still have insufficient sliding properties but also fail to satisfy the mechanical properties of the tubular bodies, causing cracks and Easy to cause destruction. Therefore, the inventors of the present invention investigated the purpose of obtaining a polyester tubular body that satisfies sliding properties and mechanical properties at the same time, and found that a tubular body made of a composition containing a specific additive to thermoplastic polyester. The present invention has been achieved by discovering that the above-mentioned object is satisfied. That is, the present invention uses polybutylene terephthalate and/or polyethylene terephthalate 100
At least one selected from synthetic waxes, substituted or unsubstituted alkylene bis fatty acid amides, and montan wax or modified products thereof, per part by weight.
A polyester tubular body is provided in which a compound containing 0.01 to 5 parts by weight is extruded into a tubular shape, and a linear material is inserted into the hollow part at the same time as or after the molding. The above additive of the present invention is a compound known as a lubricant for ordinary thermoplastic resins, but not all so-called lubricants have the same effect as the present invention, and instead of the additive of the present invention, for example, Metallic soaps, polyalkylsiloxanes, which are common lubricants,
Even if polyfluorinated ethylene, graphite, etc. are used, a tubular body made of a blend of polyester and these additives cannot achieve the effects aimed at by the present invention. Polybutylene terephthalate (PBT) and polyethylene terephthalate (PET) used in the present invention are essentially thermoplastic polyesters formed by condensation polymerization of terephthalic acid or its derivatives and 1,4-butanediol or ethylene glycol. In proportion, other dicarboxylic acids such as isophthalic acid, adipic acid, sebacic acid, decanedicarboxylic acid, ethylene glycol, neopentyl glycol, 1,4-butanediol, hexamethylene glycol, decamethylene glycol and polyethylene glycol, polytetra Other diols such as polyalkylene glycols such as methylene glycol can be included as copolymerized components. These polyesters preferably have a relative viscosity of 1.2 to 2.0, particularly 1.3 to 1.85, as measured in a 0.5% orthochlorophenol solution at 25°C. The synthetic wax used as an additive in the present invention is a synthetic polyalkylene wax having a softening point of 113 to 135°C, and specifically includes polyethylene wax and polypropylene wax. Substituted or unsubstituted alkylene bis fatty acid amide is a compound consisting of an alkylene group (having 2 to 12 carbon atoms), a fatty acid group (having 2 to 30 carbon atoms), and a substituent (preferably hindered phenols). Specific examples include ethylene bisstearamide, hexene bislauric acid amide, and ethylene bis-3 (3,5 di-tert-butyl, hydroxyphenol) propanamide. In addition, montan wax and its modified products are those in which part or all of the fatty acid ester, which is the main component of montan wax and wax, is replaced with other alcohol components, or alkali metals such as sodium and potassium, or alkali metals such as calcium, magnesium, and barium. A modified product of metal salts such as earth metals, with a hydrocarbon compound content of 50%.
% or less and is solid at room temperature. These additives are added to polyester singly or in combination of two or more, and the amount added is 0.01 to 5 parts by weight per 100 parts by weight of polybutylene terephthalate or polyethylene terephthalate.
Preferably it is 0.05 to 3 parts by weight. The amount added
If it is less than 0.01 part by weight, the surface smoothness effect will not be exhibited.
If it exceeds 5 parts by weight, the mechanical properties of the tubular body will deteriorate, which is not preferable. The compound forming the polyester tubular body of the present invention may further include lubricants other than those mentioned above, powdery or fibrous fillers or reinforcing agents, plasticizers, flame retardants, nucleating agents,
Antioxidants, ultraviolet absorbers, heat stabilizers, pigments, dyes, etc. can be contained. There are no particular restrictions on the means for blending the above additives into the polyester, and there are methods for obtaining a pellet-like blend by supplying this to an extruder with or without premixing in a tumbler or Henschel mixer, and methods for obtaining a pellet-like blend. Alternatively, there may be a method in which the additive and the polyester are directly supplied to a molding machine separately to mold the tubular body. The method for forming the tubular body is not limited to the usual methods, such as a method of supplying the compound to an extruder, heating and melt-kneading it at about 240 to 300°C, and then melting and extruding the hollow tubular body from a die of an appropriately shaped shape, and the above-mentioned method. Examples include a method in which a so-called electric wire-coated tubular body is formed by extruding a melted product simultaneously with a metal wire. In the former method, better mechanical properties can be expected by appropriately stretching or heat-treating the obtained tubular objects such as tubes and pipes, while in the latter method, by interposing an appropriate primer between the metal and the coating polymer, Adhesive strength can be further improved. In the present invention, when the tubular body obtained by the former method is molded, a linear object is inserted after molding. At that time, it is preferable to apply a lubricant such as grease to the linear object. The polyester tubular body of the present invention has extremely excellent sliding properties and mechanical properties, so it has good surface smoothness during sliding, little wear, and improved durability, making it suitable for industrial tubing. It is useful as a coating for pipes and electric wires. The present invention will be further explained below with reference to Examples. Example 1 For 100 parts by weight of polybutylene terephthalate (PBT) with a relative viscosity of 1.70 or polybutylene terephthalate decanedicarboxylate (PBT/D, T/D molar ratio; 70/30) with a relative viscosity of 1.68, as shown in Table 1. The additives shown were blended in the proportions shown in Table 1 and melt-kneaded using a screw extruder set at 250°C to form chips. Next, use this chip
It was dried for 5 hours in a hot air dryer at 130°C. The dried chips were subjected to an extruder equipped with a 40 mmφ screw and tube die, and the cylinder temperature was
A tube with an outer diameter of 5 mm and an inner diameter of 3 mm was melt-extruded at a die temperature of 250°C and a die temperature of 250°C, and was cooled with water. The obtained tube was cut into a length of 500 mm, a metal wire with a length of 1000 mm and a diameter of 2.5 mm with a greased surface was inserted into the tube, and the tubular body was bent into a U shape and fixed. Next, the surface smoothness was determined by measuring the force (Kg) when pulling out the metal wire at a speed of 50 mm/min. In addition, the metal wire of the tubular body set in the same manner as above was reciprocated at a rate of 120 times/min, and the number of reciprocating movements until cracks appeared in the tubular body was measured, and the mechanical properties of the tube during sliding were determined. did. The results are shown in Table 1.

[Table] Example 2 The additives shown in Table 2 were blended in the proportions shown in Table 2 to 100 parts by weight of polyethylene terephthalate (PET) having a relative viscosity of 1.45, and the mixture was melt-kneaded and made into chips. Next, this chip was molded into a tube in the same manner as in Example 1. In this case, the melt-kneading temperature and tube molding temperature were 280°C. The results are shown in Table 2.

[Table] Example 3 For 100 parts by weight of polybutylene terephthalate (PBT) with a relative viscosity of 1.70 or polybutylene terephthalate decanedicarboxylate (PBT/D, T/D molar ratio; 70/30) as shown in Table 3. The additives were blended in the proportions shown in Table 3 and melt-kneaded using a screw extruder set at 250°C to form chips. Next, the chips were dried for 5 hours in a hot air dryer at 130°C. This dried chip was applied to an extruder equipped with a 40 mmφ screw and a die for wire coating, and was extruded and coated onto a copper wire with a diameter of 0.2 mm at a speed of 300 m/min under conditions of a cylinder temperature of 260°C and a die of 260°C, and a coated tubular resin layer was formed. A wire covering with a thickness of 50μ was obtained. Two coated wires were wound around iron wire with a diameter of 10 mm and a length of 100 mm, and the wires were rubbed against each other at a rate of 30 times per minute. The surface friction characteristics were measured and determined. In addition, a 1000 mm coated wire was stretched 10% and left at 150°C for 1 hour to determine whether or not cracks would form on the surface.Table 3 shows the results of determining the mechanical properties of the coated wire.

【table】

[Table] Example 4 Additives shown in Table 4 were blended in the proportions shown in Table 4 to 100 parts by weight of polyethylene terephthalate (PET) having a relative viscosity of 1.45, and the mixture was melt-kneaded and made into chips. Next, this chip was molded into a wire covering in the same manner as in Example 3. In this case, the melt-kneading temperature and the forming temperature of the wire covering were 285°C. The results are shown in Table 4.

【table】

Claims (1)

[Claims] 1 For 100 parts by weight of polybutylene terephthalate and/or polyethylene terephthalate,
A compound containing 0.01 to 5 parts by weight of at least one selected from synthetic waxes, substituted or unsubstituted alkylene bis fatty acid amides, and montan wax or modified products thereof is extruded into a tubular shape, and at the same time or after molding, it is poured into the hollow part. A polyester tubular body with a linear object inserted.