JP2019165004A - Insulation tube - Google Patents

Abstract

To provide an insulation tube having excellent durability, electric characteristics, and flame retardancy.SOLUTION: An insulation tube has one or more layers mainly made of a polyarylene sulfide resin, and at least one of the layers is a layer composed of a polyarylene sulfide resin with a melting point of 275°C or less.SELECTED DRAWING: None

Description

  The present invention relates to an insulating tube having excellent durability, electrical characteristics, and flame retardancy.

Conventionally, polyolefin, polyester, polyimide film, etc. are extruded as insulation coating materials for electric wires used inside and / or outside refrigerators, refrigerators, compressors, motors such as air conditioners and automobiles, and various electric and electronic devices. Insulating tubes formed by processing into a tube shape, or by winding a film directly or by applying an adhesive and applying an ultrasonic sealing process are employed.
With the recent miniaturization of equipment, the insulating tube is also required to be thin. In order to cope with this, a tube made by extrusion molding of two or more layers that does not use an adhesive has been studied. However, since a compatible resin is selected, it is difficult to achieve both heat resistance and flame retardancy. (Patent documents 1, 2). In addition, high durability such as heat resistance and moist heat resistance is required because it is used for a long time under harsh environments such as high humidity and high temperature, and insulation using polyarylene phenylene sulfide is required to improve this. Although the tube has been studied, the durability of the material itself can be improved, but there is a problem that the durability when the tube is used for a long time, particularly the adhesion durability of the joint portion between the films is low (patent) Reference 3).

JP-A-60-202617 JP-A-60-195812 JP 10-13661 A

  An object of the present invention is to solve the above-described problems. That is, an object of the present invention is to provide an insulating tube having excellent durability, electrical characteristics, and flame retardancy.

  The insulating tube of the present invention has the following configuration in order to solve the above problems. That is, an insulating material characterized in that it has at least one layer mainly composed of polyarylene sulfide resin, and at least one of the layers is a layer composed of polyarylene sulfide resin having a melting point of 275 ° C. or less. It is a tube.

Since the insulating tube of the present invention is excellent in durability, electrical characteristics, and flame retardancy, it is used inside and / or outside of motors such as refrigeration / freezers, compressors, air conditioners and automobiles, and various electric / electronic devices. It can be suitably used as an insulating coating material for electric wires.

The insulating tube of the present invention refers to a resin formed into a cylindrical shape by extrusion or molding.
The insulating tube of the present invention includes at least one layer mainly composed of polyarylene sulfide resin. Here, the main component means that 80% by mass or more of the raw material constituting the insulating tube is occupied. By using a polyarylene sulfide resin as a main component, excellent characteristics such as durability and flame retardancy can be expressed.
The polyarylene sulfide resin used for the insulating tube of the present invention is a copolymer having a repeating unit of-(Ar-S)-. Examples of Ar include units represented by the following formulas (1) to (11).

(R1 and R2 are substituents selected from hydrogen, an alkyl group, an alkoxy group, and a halogen group, and R1 and R2 may be the same or different.)
As the repeating unit of the polyarylene sulfide resin used in the insulating tube of the present invention, a p-arylene sulfide unit represented by the above formula (1) is preferable, and typical examples thereof include polyphenylene sulfide, polyphenylene sulfide sulfone, Examples thereof include polyphenylene sulfide ketones, and particularly preferred p-arylene sulfide units are preferably exemplified from the viewpoint of film properties and economy.

  In the polyarylene sulfide resin which is the main component of the insulating tube of the present invention, the p-phenylene sulfide unit represented by the following structural formula is 75 to 100 mol%, more preferably 75 to 98 mol%, more preferably all repeating units. It is preferable to occupy 85-98 mol%. When the main component is less than 75 mol%, the durability may be lowered.

At least one layer constituting the insulating tube of the present invention is made of a polyarylene sulfide resin having a melting point of 275 ° C. or lower. By providing the layer having the above melting point, both workability and durability when used as an insulating tube can be achieved. When the melting point range is exceeded, processing at a high temperature is performed, and workability may be deteriorated. When the melting point is below the above range, the heat resistance of the insulating tube may be lowered. The melting point of the polyarylene sulfide resin to be used is preferably 235 to 275 ° C, more preferably 245 to 265 ° C. The melting point of the resin constituting the insulating tube can be confirmed by the method described later.
The polyarylene sulfide resin having a melting point of 275 ° C. or less used for the insulating tube of the present invention is 2 to 25 mol%, preferably 2 to 15 mol% of the repeating unit of the polyarylene sulfide resin. It can be obtained by polymerization. If the copolymerized unit is less than 2 mol%, the melting point of the polyarylene sulfide resin cannot be within the above-described range, and the processability may be lowered. On the other hand, if the copolymerized unit exceeds 25 mol%, the degree of polymerization of the polyarylene sulfide resin becomes low, and it becomes difficult to increase the molecular weight, so that the mechanical properties may be lowered.

  Preferred copolymer units are

(Here, X represents an alkylene, CO, or SO ₂ unit.)

(Wherein R represents an alkyl, nitro, phenylene, or alkoxy group), and a particularly preferred copolymer unit is an m-phenylene sulfide unit.

  The mode of copolymerization with the copolymerization component is not particularly limited, but is preferably a random copolymer. The melting point of the polyphenylene sulfide resin can be confirmed by using the method described later.

  The composition of the polyarylene sulfide resin constituting the insulating tube of the present invention contains various additives such as an antioxidant, a heat stabilizer, an antistatic agent and an antiblocking agent within the range not impairing the effects of the present invention. You may let them.

  As the method for producing the insulating tube of the present invention, a film made of a thermoplastic resin is decorated by vacuum molding or compression molding, and then an unnecessary portion is cut off to form a tube. Extrusion molding (direct tube from an extruder) Thermoplastic resin is shaped and cooled immediately after extrusion to form), tubular molding (melted thermoplastic resin is extruded into a tube shape from an annular die, and gas is injected while applying temperature to the tube. Inflated and stretched in a direction perpendicular to the film flow direction) or spiral tube method using a thermoplastic resin film (strip shape in the longitudinal direction of the film, then spiral so that some overlap) And the like, but the method is not limited to this.Among various molding methods, it is preferable that a film made of a thermoplastic resin is used to form a tube, from the viewpoint of reducing pinholes and improving electrical characteristics. Among the methods using a film, a spiral tube The method of shaping by the method is more preferred.

  The film used when the insulating tube of the present invention is manufactured by the spiral tube method is a film made of a thermoplastic resin without using an adhesive even if an adhesive is applied to at least one side and bonded using an adhesive. May be partially melted and fused.

  When a polyarylene sulfide film is used as the material for the insulating tube of the present invention, the polyarylene sulfide film is preferably biaxially stretched from the viewpoint of durability. When the polyarylene sulfide film used is an unstretched or uniaxially stretched film, the mechanical properties may be deteriorated when used at a high temperature for a long time. Whether or not the polyarylene sulfide film is biaxially stretched can be confirmed by evaluating the shrinkage behavior during heating described later.

  The insulating tube of the present invention preferably has a laminated configuration. By having the above configuration, it is possible to have a plurality of characteristics such as durability and insulation. When the layer composition is A and B, the laminated structure is A / B, A / B / A, A / B / A / B, A / B / A / B / A, etc. However, it is not limited to this. Further, when C is a composition different from A and B, it is possible to develop different characteristics by adopting a configuration such as A / C or A / B / C.

  The insulating tube of the present invention may include a layer made of another thermoplastic resin in addition to the layer mainly composed of polyarylene sulfide resin. Examples of the thermoplastic resin constituting the insulating tube include thermoplastic polyimide resin, polyamide resin, polyether ether ketone, polyether imide, thermoplastic polyamide imide resin, polyolefin resin such as polyethylene and polypropylene, polystyrene, polycarbonate, acrylic resin , Urethane resins, fluororesins, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyketones, and epoxy resins, but are not limited thereto. Also, two or more selected from the above and polyarylene sulfides can be blended and used.

  When a polyarylene sulfide film is used as the material for the insulating tube of the present invention, the polyarylene sulfide film preferably has a laminate structure of two or more layers. By having a layer structure of two or more layers, it is possible to have a plurality of characteristics such as durability and insulation. As a laminated structure, when the composition of the layers is (I) and (II), two layers (I) / (II), (I) / (II) / (I), (II) / (I) / (II), (II) / (I) / (II) / (I), (II) / (I) / (II) / (I) / (II), etc. It is not limited to. Moreover, it can also be set as the layer structure which added the layer which consists of a composition different from (I)-(II) further.

  The thickness of the insulating tube of the present invention is preferably 10 to 500 μm, and more preferably 25 to 300 μm. By setting it as said thickness, flexibility and insulation can be made compatible. When the thickness of the insulating tube is 10 μm or less, there is no stiffness when the tube is bent, and it may be bent or damaged. Further, if it is 500 μm or more, the rigidity is strong and it may be difficult to bend into an arbitrary shape. The thickness of the insulating tube can be confirmed by a method described later. The thickness of the insulating tube can be adjusted by adjusting the molding conditions or by adjusting the thickness of the film when a film is used.

  The insulating tube of the present invention preferably has pores in the tube. When the tube has pores, the proportion of the pores (porosity) is preferably 10% or more. By having the above porosity, the electrical characteristics as an insulating tube can be improved. Here, the porosity refers to the ratio of the area of the pores included in the image when the cross-sectional area of the arbitrary size of the insulating tube is 100, and no voids are observed in the cross-sectional image of the arbitrary size. In this case, the porosity is 0%. When the porosity is less than 10%, the number of pores contained in the insulating tube is reduced, and the proportion of air having a low dielectric constant in the tube is reduced, so that the electrical characteristics may be deteriorated. Further, the higher the porosity, the better, but 50% or less is preferable from the viewpoint of practicality.

  As a method for forming pores in the insulating tube of the present invention, a dry method (method of making a porous material by stretching a melted and extruded resin) is used because the process can be simplified and the productivity is excellent. Is preferred. Further, among the dry methods, in consideration of residence stability and productivity, a method of forming pores around the particles by stretching them with inorganic particles or organic particles in a tube is suitably used.

  The concentration of the organic / inorganic particles contained in the insulating tube of the present invention is 10 to 60% by mass when the raw material composition of the layer made of resin and other additives constituting the insulating tube is 100% by mass. It is preferably 20 to 60% by mass. By setting the particle concentration within the above range, pores can be efficiently formed. When the particle concentration is less than 10% by mass, the particle concentration is low, so that vacancies are hardly formed, and the effect of improving electrical characteristics may be poor. On the other hand, if the particle concentration exceeds 60% by mass, the extrudability and the resin become brittle, so that the mechanical properties may be deteriorated.

    Inorganic particles preferably used in the insulating tube of the present invention include oxide ceramics such as alumina, silica, titania, zirconia, magnesia, ceria, yttria, zinc oxide and iron oxide, and nitrides such as silicon nitride, titanium nitride and boron nitride. Ceramics, silicon carbide, calcium carbonate, aluminum sulfate, barium sulfate, potassium titanate, talc, kaolin clay, kaolinite, halloysite, pyrophyllite, montmorillonite, sericite, mica, amicite, bentonite, asbestos, zeolite, Examples thereof include inorganic compounds such as calcium silicate, magnesium silicate, diatomaceous earth, ceramics such as silica sand, and glass fiber. The organic particles preferably used in the insulating tube of the present invention have a melting point higher than that of polyarylene sulfide constituting the insulating tube, such as thermoplastic polyimide resin, aromatic polyether ketone, aromatic aryl ketone, and liquid crystal polymer (LCP). Or resin which has a softening point is mentioned. One kind of particles may be used, or a plurality of kinds may be mixed and used.

  The dielectric breakdown voltage of the insulating tube of the present invention is preferably 200 kv / mm or more, and more preferably 250 kV / mm or more. The higher the dielectric breakdown voltage, the better. However, the upper limit is 500 kV / mm considering the realizable range. The dielectric breakdown voltage is a limit voltage value when the applied voltage is increased until dielectric breakdown occurs, and can be measured based on JIS C2151 (2006). If the dielectric breakdown voltage is less than 200 kV / mm, when the insulating tube is put into practical use, sufficient insulating properties may not be exhibited and it may not be used. The dielectric breakdown voltage can be evaluated by the method described later.

  In the insulating tube of the present invention, the partial discharge start voltage in terms of 100 μm after the heat treatment at 150 ° C./1000 hours is preferably 1000 V or more, and more preferably 1300 V or more. By having the above characteristics, an excellent withstand voltage life can be exhibited when used as an insulating material. When the partial discharge start voltage in terms of 100 μm after the heat treatment at 150 ° C./1000 hours is less than 1000 V, the insulation tube may not withstand long-term practical use when used at a high temperature. Moreover, although the partial discharge start voltage is preferably as high as possible, the realizable range is 3000 V or less. The partial discharge start voltage can be evaluated by the method described later. In order to set the partial discharge start voltage in terms of 100 μm within the above range, it can be achieved by including holes in the insulating tube. The partial discharge start voltage in terms of 100 μm after the heat treatment at 150 ° C./1000 hours can be confirmed by the method described later.

  The method for producing an insulating tube of the present invention will be described by taking a case where a polyarylene sulfide film is used as a material as an example, but the present invention is not limited to this example.

  Sodium sulfide, p-dichlorobenzene, and m-dichlorobenzene are blended in the ratios referred to in the present invention, and in the presence of a polymerization aid in an amide polar solvent such as N-methyl-2-pyrrolidone (NMP), under high temperature and high pressure. React with. If necessary, a copolymer component such as trihalobenzene may be included. As a polymerization degree adjusting agent, caustic potash or alkali metal carboxylate is added, and a polymerization reaction is performed at a temperature of 200 to 290 ° C. After the polymerization, the polymer is cooled, and the polymer is filtered as a water slurry through a filter to obtain a granular polymer. This is washed with high temperature water at 30 to 100 ° C., then washed with acetic acid aqueous solution or aqueous acetate solution (for example, sodium acetate or calcium acetate) twice or more, more preferably 3 times or more, and then 30 to 80 ° C. After washing with ion-exchanged water and drying, a granular polymer of copolymerized polyphenylene sulfide (PPS) is obtained.

  Further, only sodium sulfide and p-dichlorobenzene are reacted in an amide polar solvent such as N-methyl-2-pyrrolidone (NMP) at high temperature and high pressure in the presence of a polymerization aid. If necessary, a copolymer component such as trihalobenzene may be included. As a polymerization degree adjusting agent, caustic potash or alkali metal carboxylate is added, and a polymerization reaction is performed at a temperature of 200 to 290 ° C. After the polymerization, the polymer is cooled, and the polymer is filtered as a water slurry through a filter to obtain a granular polymer. This is washed with high temperature water at 30 to 100 ° C., then washed with acetic acid aqueous solution or aqueous acetate solution (for example, sodium acetate or calcium acetate) twice or more, more preferably 3 times or more, and then 30 to 80 ° C. After washing with ion-exchanged water and drying, a polyphenylene sulfide (PPS) granular polymer is obtained.

  The copolymerized PPS granular polymer and PPS granular polymer obtained above were separately fed into an extruder with a vent heated to 300 to 330, melt extruded into a strand, and cooled with water at a temperature of 25 ° C. Thereafter, cutting is performed to produce a chip.

  The chips were individually dried under reduced pressure at 180 ° C. for 3 hours, and then separately supplied to two extruders heated to 300 to 320 ° C., and in a molten state, two layers (stacked) The structure is PPS / copolymerized PPS = (I) / (II), and the lamination ratio is (I) :( II) = 1-5: 1-5), and then discharged from the T-die die. To do. This sheet-like material is brought into close contact with a cooling drum having a surface temperature of 20 to 70 ° C. to be cooled and solidified to obtain a substantially non-oriented unstretched film.

  Next, in the case of biaxial stretching, the unstretched film obtained above is sequentially biaxially stretched or simultaneously biaxially stretched in the range from the glass transition point of the copolymerized PPS resin to the cold crystallization temperature of the PPS. After biaxial stretching with a machine, a one-stage or multi-stage heat treatment is performed at a temperature in the range of 150 to 280 ° C. to obtain a biaxially oriented polyarylene sulfide film.

  The resulting polyarylene sulfide film is slit to a width of 2 cm in the film width direction and wound up in a roll shape. Next, the above roll is uniformly wound on a 0.5 cm diameter SUS rod whose surface has been subjected to fluorine processing so that the overlapping portion is 1 cm with the surface on which the copolymerized PPS is laminated facing inside, and winding starts. And stop the end of winding with tape. Next, after the overlapping portion is fused with ultrasonic waves using a small ultrasonic fusing device having a tip diameter of 0.5 cm, the winding core rod is removed to obtain an insulating tube.

  Since the insulating tube of the present invention is a thin film and excellent in durability, electrical insulation and adhesion durability, it can be used inside and / or outside of motors such as refrigeration / freezers, compressors, air conditioners and automobiles, and various electric / electronic devices. It is useful as an insulating coating material for electric wires used.

[Measurement method of characteristics]
(1) Thickness of insulating tube and thickness of each layer to be formed Cut from the end face of the insulating tube with scissors parallel to the longitudinal direction of the tube. For the cross section corresponding to the longitudinal direction of the tube from the cut sample, an ion etching treatment was performed for 10 minutes using a sputtering apparatus under conditions of a degree of vacuum of 10 ⁻³ Torr, a voltage of 0.25 KV, and a current of 12.5 mA. After cutting, the surface is subjected to gold sputtering, and observed with a scanning electron microscope at a magnification of 500 times, and an image that can observe the entire thickness direction of the sample is collected. From the image obtained by observation, the thickness of the hottest part of the sample was read from the image obtained by observation, and the thickness of the insulating tube and the thickness of each layer constituting this were measured.
When the whole thickness direction of the laminate cannot be confirmed at the above magnification, several images are taken in the thickness direction, and the whole image is confirmed by connecting the images. The sample used for the measurement of thickness selected 10 places in total of arbitrary places, and made the average of the measured value of 10 samples the thickness of the sample, and the thickness of each layer.

(2) The melting point of the resin constituting the insulating tube is cut from the end face of the insulating tube with scissors parallel to the longitudinal direction of the tube. Using a microplane from the cut-out insulating tube, an arbitrary layer to be measured is scraped and sampled within a range not exceeding the thickness confirmed in (1). In accordance with JIS K7121-1987, a differential scanning calorimeter is used as a differential scanning calorimeter DSC (RDC220), and a data analyzer is a disk station (SSC / 5200) manufactured by Seiko Instruments Inc. The temperature is raised to 20 ° C. at a rate of temperature rise of 20 ° C./min (1st Run). After the sample is taken out and rapidly cooled, the temperature is raised from room temperature to 350 ° C. at a heating rate of 20 ° C./min (2nd Run).

  The melting point of the resin is the melting point (Tm), which is the peak temperature of the endothermic peak of melting confirmed on the 2nd Run DSC chart.

(3) Shrinkage behavior during heating of the insulating tube The insulating tube is cut open in parallel to the longitudinal direction of the tube, and a sample having a sample width of 4 mm and a sample length of 15 mm is cut in the tube longitudinal direction and the transverse direction, respectively. Next, a sample is set on a thermomechanical measuring apparatus TMA / SS6100 (Seiko Instruments) at a distance between chucks of 5 mm and a load of 3 g, and the melting point is the lowest among the layers constituting the insulating tube confirmed in (2) from room temperature. The temperature was raised to a melting point of the resin of the layer of −40 ° C. at a heating rate of 10 ° C./min, held for 10 minutes, and the dimensional change (%) was read. The measurement was carried out at n = 5 in the longitudinal direction and the transverse direction of the tube, the average value in each direction was calculated, and evaluated according to the following criteria.
0: (Unstretched) The dimensional change in both the longitudinal direction and the transverse direction is 1.0% or less, and the ratio of the dimensional change (lateral direction / longitudinal direction) is 0.1 to 1.1.
1: (uniaxial stretching) The dimensional change amount in either the longitudinal direction or the transverse direction is greater than 1.0% and the ratio of the dimensional change amount (lateral direction / longitudinal direction) is greater than 0.1, or Less than 1 2: (Biaxial stretching) The amount of dimensional change in both the longitudinal direction and the transverse direction is 1% or more. (4) Electrical characteristics of the insulating tube a. A dielectric breakdown voltage insulating tube cut into a length of 5 cm in the longitudinal direction of the tube and conditioned for 24 hours in an environment of 23 ° C. and 65% RH is used as a sample. Prepare the upper electrode as a rod-shaped electrode with a diameter of 0.5 cm and a length of 3 cm, the lower electrode as a pedestal with a cylindrical shape with a diameter of 75 mm and a height of 15 mm. The upper electrode protrudes from the end of the electrode and does not contact the electrode Install it completely inside the insulation tube. Next, the dielectric breakdown voltage was measured under the conditions of a frequency of 60 Hz and a boosting rate of 1000 V / sec using an AC dielectric breakdown tester (manufactured by Kasuga Electric Co., Ltd., AC 30 kV). The dielectric breakdown voltage per unit thickness was calculated from the obtained dielectric breakdown voltage (kV) and the thickness (μm) of the insulating tube. The measurement was performed at n = 10, and the average value was taken as the dielectric breakdown voltage (kV / mm) of the sample.

b. Partial discharge start voltage A 2 × 2 cm sample is cut out from an arbitrary portion of the insulating tube, a brass rod having a diameter of 75 mm and a length of 10 mm is passed through the tube, and a treatment at 150 ° C./1000 hours is performed in a hot air oven. The treated sample was conditioned for 24 hours in an environment of 23 ° C. and 65% RH, and then placed in an electronic micrometer (Anritsu Co., Ltd., K-312A, needle pressure 30 g) in an atmosphere of 23 ° C. and 65% RH. Then, measure the thickness at any three locations of the sample, and set the average value as the thickness (μm) of the sample. Next, the partial discharge starting voltage is measured using a partial discharge measuring instrument (model name “QM-50”) manufactured by Mitsubishi Cable Industries, Ltd. The test piece is sandwiched between a stainless steel plate and a brass electrode, An AC voltage was applied to the stainless steel plate and the brass electrode at a pressure increase rate of 200 Vrms / second, and the voltage value was measured when the discharge charge amount measured by the partial discharge measuring device reached 100 pC. Inserted into the following equation, the partial discharge start voltage in terms of 100 μm of the sample is obtained.
Partial discharge start voltage (V) in terms of 100 μm = measured value (V) / thickness (μm) × 100 (μm)
The measurement was carried out with n = 10, and the numerical value obtained by arithmetic average was used as the partial discharge start voltage in terms of 100 μm of the sample.

(5) Durability of the insulating tube A length of 15 cm is cut out from the insulating tube in the longitudinal direction of the tube, and cut from the end surface of the insulating tube with scissors parallel to the longitudinal direction of the tube. A sample having a length of 10 cm in the longitudinal direction of the tube and a width of 1 cm in the transverse direction of the tube is sampled from the cut sample to obtain a sample for evaluation. The above sample was subjected to heat treatment for 1000 hours in a hot air oven set at a temperature of 200 ° C., the breaking strength before and after the heat treatment was measured, and the strength retention was calculated from the following formula. The breaking strength is set according to the method specified in JIS-C2151, using a Tensilon tensile tester, setting a sample piece having a width of 1 cm so that the length between chucks is 10 cm, and performing a tensile test at a tensile speed of 300 mm / min. It measured 10 times on these conditions, the average value was calculated | required, and it was set as the intensity | strength retention rate of the sample.

Strength retention (%) = Y / Y0 × 100
Y0: Breaking strength before heat treatment (MPa)
Y: Breaking strength after heat treatment (MPa)
A: Strength retention is 75% or more,
B: Strength retention ratio is 65% or more and less than 75% C: Strength retention ratio is not 65% or the appearance of the sample after the heat treatment is visually observed, and the adhesion between the layers constituting the insulating tube is evaluated according to the following criteria. did.
A: One breakage point (good adhesion between layers)
B: There are two fracture locations (inadequate adhesion between layers).

(6) Workability of the insulating tube The insulating tube is cut to a length of 5 cm and used as a sample. An SUS round bar (manufactured by MISUMI Corporation, MRS 0.7) having a diameter of 0.7 cm and a length of 10 cm is passed through the diameter of the tube and adjusted so that the insulating tube is arranged at the center. Next, the insulating tube together with the SUS round bar is left for 10 minutes in an oven set at the melting point of the resin with the lowest melting point of the resin constituting the insulating tube for 10 minutes, and then taken out and cooled. The state of the insulating tube after cooling was evaluated according to the following criteria. In addition, melting | fusing point of resin of the layer with the lowest melting | fusing point among the layers which comprise an insulating tube can be confirmed with the method as described in (1).
A: The insulation tube cannot be removed from the SUS round bar by hand (good workability)
B: The insulation tube can be removed from the round bar of SUS by hand (workability is poor).

(7) Cut off the flame-retardant insulating tube of the insulating tube to a length of 127 ± 1 mm to make a sample. Using this sample, flame retardancy was evaluated by a vertical combustion test based on the UL-94 standard. Adjust the height of the blue flame without yellow tip of the burner to 19.5 mm (3/4 inch), expose the center of the lower end of the test piece held vertically to the flame for 10 seconds, then release it from the flame until extinguishing The time was recorded. After extinguishing the flame, the second flame is applied for 10 seconds in the same manner as the first, and the flame is separated from the flame again to measure the combustion time, and the flame retardance is judged from the state of combustion. Evaluation was performed at n = 5, and the determination was made according to the following criteria.

    A: The total time to flame extinction after 10 times of flame contact after 5 times contact with 5 test pieces is within 50 seconds, and the time to flame extinction after each flame contact is within 10 seconds. is there.

    B: The total time to extinguish after 10 times of flame contact with 5 test pieces 2 times in total is longer than 50 seconds, and the time to extinction after each flame contact is longer than 10 seconds.

(8) Withstand voltage life After cutting the insulation tube to a length of 5 cm in the longitudinal direction of the tube, a brass rod having a diameter of 75 mm and a height of 10 mm is passed through the tube, and is treated at 150 ° C./1000 hours in a hot air oven. . For the treated sample, the sample was conditioned for 24 hours in an environment of 23 ° C. and 65% RH, the upper electrode was a rod-shaped electrode having a diameter of 0.5 cm and a length of 3 cm, and the lower electrode serving as a pedestal was φ75 mm in height. Prepare a 15 mm cylindrical shape, and install the upper electrode inside the insulating tube completely so that the end of the electrode does not protrude from the electrode. Use an AC breakdown tester (AC30 kV, manufactured by Kasuga Electric Co., Ltd.). Then, the voltage was applied at an applied voltage of 2 kV and a frequency of 80 kHz, and the time (minutes) from the application to the breakdown was measured. The evaluation was carried out with n = 5, and the average value was taken as the withstand voltage life of the sample, and A: time to be destroyed after the application of electricity was 60 minutes or more B: until after the application of electricity to destruction The time from 15 minutes to less than 60 minutes C: The time from destruction to destruction after less than 15 minutes.

(9) Porosity After cutting the insulating tube into a length of 30 cm in the longitudinal direction of the tube, it is cut from the end face of the insulating tube with scissors parallel to the longitudinal direction of the tube. From the cut sample, a sample having a length of 25 cm in the longitudinal direction of the tube and a width of 1 cm in the transverse direction of the tube is sampled, and the weight is measured with a precision balance. The thickness (cm) is measured using an electronic micrometer (Anritsu Co., Ltd., K-312A type, needle pressure 30 g) at any three points on this sample, and the average value is calculated. The average value of the measured weight and thickness is inserted into the following formula, and the porosity of the insulating tube is calculated.
Porosity (%) = [weight (g) / [average thickness (cm) × 25 cm × 1 cm]] / theoretical density (g / cm ³ )
Theoretical density Polypropylene 0.94 g / cm ³
Polyphenylene sulfide 1.34 g / cm ³

(Reference Example 1) Method for Producing Copolymerized PPS Resin 100 moles of sodium sulfide nonahydrate, 45 moles of sodium acetate and 25 liters of N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP) in an autoclave. Was gradually heated to a temperature of 220 ° C. while stirring, and the contained water was removed by distillation. In the system after dehydration, 90 mol of p-dichlorobenzene as a main component monomer and 10 mol of m-dichlorobenzene as a secondary component monomer were added together with 5 liters of NMP, and nitrogen was supplied at a temperature of 170 ° C. at 3 kg / cm 3. After pressurizing and sealing at ² , the temperature was raised and polymerization was carried out at 260 ° C. for 4 hours. After completion of the polymerization, the polymer was cooled, the polymer was precipitated in distilled water, and a small polymer was collected with a wire mesh having a 150 mesh opening. The small polymer obtained in this way was washed twice with distilled water at 90 ° C., then washed three times with an aqueous sodium acetate solution, then washed once with distilled water, and dried at a temperature of 120 ° C. under reduced pressure. Thus, a copolymer PPS resin granule having a melting point of 255 ° C. was obtained. The obtained granules were put into a vented co-rotating twin-screw kneading extruder (manufactured by Nippon Steel Works, screw diameter 30 mm, screw length / screw diameter = 45.5) heated to 300 ° C., and a residence time of 90 Second, the melt was extruded at a screw speed of 150 revolutions / minute, discharged into a strand, cooled with water at a temperature of 25 ° C., and immediately cut to produce a copolymer PPS resin chip.

Reference Example 2 Production Method of PPS Resin An autoclave was charged with 100 moles of sodium sulfide nonahydrate, 45 moles of sodium acetate and 25 liters of N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP). While stirring, the temperature was gradually raised to a temperature of 220 ° C., and the contained water was removed by distillation. In the system after the dehydration, 100 moles of p-dichlorobenzene as a main component monomer was added together with 5 liters of NMP, nitrogen was pressurized and sealed at 3 kg / cm ² at a temperature of 170 ° C., and the temperature was increased. Polymerization was performed at a temperature of 4 ° C. for 4 hours. After completion of the polymerization, the polymer was cooled, the polymer was precipitated in distilled water, and a small polymer was collected with a wire mesh having a 150 mesh opening. The small polymer obtained in this way was washed twice with distilled water at 90 ° C., then washed three times with an aqueous sodium acetate solution, then washed once with distilled water, and dried at a temperature of 120 ° C. under reduced pressure. As a result, granules of PPS resin having a melting point of 280 ° C. were obtained. The obtained granule was charged into a vented co-rotating twin-screw kneading extruder (manufactured by Nippon Steel Works, screw diameter 30 mm, screw length / screw diameter = 45.5) heated to 330 ° C., and a residence time of 90 Second, the melt was extruded at a screw speed of 150 revolutions / minute, discharged into a strand, cooled with water at a temperature of 25 ° C., and immediately cut to produce a PPS resin chip.

(Example 1)
The copolymer PPS and PPS resin chips prepared in Reference Examples 1 and 2 were separately dried under reduced pressure at 180 ° C. for 3 hours, and then separately supplied to two extruders heated to 300 ° C. and 330 ° C., respectively. Then, after filtration through a 16 μm cut filter heated to a temperature of 320 ° C. in a molten state, two layers are formed using a laminating device at the top of the die (the laminating structure is copolymerized PPS / PPS = (I) / (II), the laminating ratio is ( I): (II) = 2: 3), melt-extruded from a die of a T die set at a temperature of 320 ° C, and then solidified by cooling while applying an electrostatic charge to a cast drum having a surface temperature of 25 ° C Thus, an unstretched film having a thickness of 500 μm was obtained. Next, after preheating the obtained unstretched film with a plurality of heating rolls heated to a surface temperature of 90 ° C., a heating roll heated to a surface temperature of 95 ° C. and a peripheral speed provided next to the heating roll. The film was stretched 3.5 times in the longitudinal direction (MD direction) between different cooling rolls at 30 ° C. The uniaxially stretched sheet thus obtained was stretched 3.5 times at a temperature of 85 ° C. in the direction perpendicular to the longitudinal direction (TD direction) using a tenter, and subsequently heat treated at 230 ° C. Subsequently, after 5% relaxation treatment was performed in the transverse direction (TD direction) for 4 seconds in a relaxation treatment zone at 230 ° C., the film edge was removed after cooling to room temperature to obtain a biaxially stretched film having a thickness of 50 μm. Next, the obtained polyarylene sulfide film is slit to a width of 2 cm in the film width direction and wound into a roll. Next, the above roll is uniformly wound on a SUS rod having a diameter of 1.0 cm whose surface has been subjected to fluorine processing so that the overlapping portion becomes 1 cm with the surface on which the copolymerized PPS is laminated on the inside, and winding starts. And stop the end of winding with tape. Next, the overlapping portion was fused with ultrasonic waves using a small ultrasonic fusing device having a tip diameter of 0.5 cm, and then the core rod was removed, and the inner diameter of the polyarylene sulfide was 1.0 cm and the thickness was 100 μm. Insulated tube was obtained. The porosity of this insulating tube was 0%.

(Example 2)
The copolymer PPS and PPS resin chips prepared in Reference Examples 1 and 2 were separately dried under reduced pressure at 180 ° C. for 3 hours, respectively, and then co-polymerized with a Plabor (Plastics Engineering Laboratory Co., Ltd.) two-layer tube molding machine. The polymerized PPS resin is melted separately at an extrusion temperature of 300 ° C. and the PPS resin is melted separately at an extrusion temperature of 330 ° C., and the molten resin is joined by an adapter, and through a die set at 320 ° C., a layer of the copolymerized PPS resin comes inside Thus, a laminated tubular body was formed. Subsequently, it is cooled by a sizing die for dimension control and taken up, and has a two-layer structure of an outer layer made of PPS resin and an inner layer made of copolymerized PPS, with a lamination ratio of outer layer / inner layer = 2/1 and an inner diameter of 1.0 cm, A laminated tube made of polyarylene sulfide having a thickness of 300 μm was obtained. The porosity of this insulating tube was 0%.

(Example 3)
80 wt% of PPS resin granules prepared in Reference Example 2 having a melting point of 280 ° C. and 30 wt% of SC5500 (D50 = 1.5 μm, D5 = 0.3 μm, D90 = 3.0 μm) manufactured by Admatechs as silica particles Then, it is put into a co-rotating twin-screw kneading extruder with a vent heated to 320 ° C. (manufactured by Nippon Steel Works, screw diameter 30 mm, screw length / screw diameter = 45.5), residence time 90 seconds, screw It was melt-extruded at a rotational speed of 150 revolutions / minute, discharged in the form of a strand, cooled with water at a temperature of 25 ° C., and immediately cut to produce a chip. The raw material A and the copolymer PPS chips prepared in Example 1 were separately dried under reduced pressure at 180 ° C. for 3 hours, and then separately supplied to two extruders heated to 330 ° C. and 300 ° C., respectively. After filtering with a 16 μm cut filter heated to a temperature of 320 ° C. in the state, two layers are formed with a laminating apparatus at the upper part of the die (the laminating structure is copolymerized PPS / raw material A = (I) / (II), the laminating ratio is (I ): (II) = 2: 3) After being melt-extruded from a die of a T die set at a temperature of 320 ° C., it is cooled and solidified by applying an electrostatic charge to a cast drum having a surface temperature of 25 ° C. An unstretched film having a thickness of 500 μm was obtained. Next, after preheating the obtained unstretched film with a plurality of heating rolls heated to a surface temperature of 90 ° C., a heating roll heated to a surface temperature of 95 ° C. and a peripheral speed provided next to the heating roll. The film was stretched 3.3 times in the longitudinal direction (MD direction) between different cooling rolls at 30 ° C. The uniaxially stretched sheet thus obtained was stretched 3.3 times at a temperature of 85 ° C. in the direction perpendicular to the longitudinal direction (TD direction) using a tenter, and subsequently heat treated at 230 ° C. Subsequently, after 5% relaxation treatment was performed in the transverse direction (TD direction) for 4 seconds in a relaxation treatment zone at 230 ° C., the film edge was removed after cooling to room temperature to obtain a biaxially stretched film having a thickness of 50 μm. Next, the obtained polyarylene sulfide film is slit to a width of 2 cm in the film width direction and wound into a roll. Next, the above roll is uniformly wound on a SUS rod having a diameter of 1.0 cm whose surface has been subjected to fluorine processing so that the overlapping portion becomes 1 cm with the surface on which the copolymerized PPS is laminated on the inside, and winding starts. And stop the end of winding with tape. Next, the overlapping portion was fused with ultrasonic waves using a small ultrasonic fusing device having a tip diameter of 0.5 cm, and then the core rod was removed, and the inner diameter of the polyarylene sulfide was 1.0 cm and the thickness was 100 μm. Insulated tube was obtained. The porosity of this insulating tube was 30%.

(Comparative Example 1)
FLX80E4 (manufactured by Sumitomo Chemical Co., Ltd.) as a polypropylene resin and Admer QF500 (manufactured by Mitsui Chemicals, Inc.) as a modified polypropylene resin are separately supplied to two extruders heated to 220 ° C. and 190 ° C. and melted. And filtered with a 16 μm cut filter heated to 200 ° C. and then with a laminating device at the top of the base (laminated configuration is FLX80E4 / Admer QF500 = (I) / (II), laminating ratio is (I) :( II) = 2: 3) After being melt-extruded from a die of a T-die set at a temperature of 220 ° C., it is cooled and solidified by applying an electrostatic charge to a cast drum having a surface temperature of 25 ° C., and a thickness of 500 μm. An unstretched film was obtained. Next, after preheating the obtained unstretched film with a plurality of heating rolls heated to a surface temperature of 125 ° C., a heating roll heated to a surface temperature of 135 ° C. and a peripheral speed provided next to the heating roll. The film was stretched 5 times in the longitudinal direction (MD direction) between different cooling rolls at 30 ° C. The uniaxially stretched sheet thus obtained was stretched 6.0 times at a temperature of 150 ° C. in the direction perpendicular to the longitudinal direction (TD direction) using a tenter, and subsequently heat treated at 155 ° C. Subsequently, after 10% relaxation treatment in the transverse direction (TD direction) for 7 seconds in a relaxation treatment zone at 155 ° C., the film edge was removed after cooling to room temperature to obtain a biaxially stretched film having a thickness of 50 μm. Next, the obtained polypropylene film is slit to a width of 2 cm in the film width direction and wound into a roll. Next, a SUS rod having a diameter of 1 cm with a fluorinated surface is wound uniformly on the roll so that the overlapping portion is 1 cm with the surface on which the copolymerized PPS is laminated on the inside. Tape the end. Next, the overlapping portion was fused with ultrasonic waves using a small ultrasonic fusing device having a tip diameter of 0.5 cm, and then the winding core rod was removed, and the inner diameter of the polypropylene film was 1.0 cm and the thickness was 100 μm. An insulating tube was obtained. The porosity of this insulating tube was 0%.

(Comparative Example 2)
The PPS resin chip produced in Reference Example 2 was dried under reduced pressure at 180 ° C. for 3 hours, then supplied to an extruder heated to 330 ° C., and filtered through a 16 μm cut filter heated to a temperature of 320 ° C. in a molten state. It was melt-extruded from a die of a T die set at a temperature of 320 ° C., and solidified by cooling while applying an electrostatic charge to a cast drum having a surface temperature of 25 ° C. to obtain an unstretched film having a thickness of 500 μm. Next, after preheating the obtained unstretched film with a plurality of heating rolls heated to a surface temperature of 90 ° C., a heating roll heated to a surface temperature of 95 ° C. and a peripheral speed provided next to the heating roll. The film was stretched 3.5 times in the longitudinal direction (MD direction) between different cooling rolls at 30 ° C. The uniaxially stretched sheet thus obtained was stretched 3.5 times at a temperature of 85 ° C. in the direction perpendicular to the longitudinal direction (TD direction) using a tenter, and subsequently heat treated at 230 ° C. Subsequently, after 5% relaxation treatment was performed in the transverse direction (TD direction) for 4 seconds in a relaxation treatment zone at 230 ° C., the film edge was removed after cooling to room temperature to obtain a biaxially stretched film having a thickness of 50 μm. Next, the obtained polyarylene sulfide film is slit to a width of 2 cm in the film width direction and wound into a roll. Next, a SUS rod having a diameter of 1 cm with a fluorinated surface is wound uniformly on the roll so that the overlapping portion is 1 cm with the surface on which the copolymerized PPS is laminated on the inside. Tape the end. Next, the overlapping portion was fused with ultrasonic waves using a small ultrasonic fusing device having a tip diameter of 0.5 cm, and then the core rod was removed, and the inner diameter of the polyarylene sulfide was 1.0 cm and the thickness was 100 μm. Insulated tube was obtained. The porosity of this insulating tube was 0%.
Table 1 shows the characteristic evaluation results of the insulating tubes obtained in Examples 1 and 2 and Comparative Examples 1 and 2.
The processability of the insulating tube was evaluated at 235 ° C. for Examples 1 and 2, 100 ° C. for Comparative Example 1, and 260 ° C. for Comparative Example 2.

Since the insulating tube of the present invention is excellent in durability, electrical insulation and durability, it is used inside and / or outside of motors and various electric / electronic devices such as refrigerators, refrigerators, compressors, air conditioners and automobiles. It can be suitably used as an insulating coating material for electric wires.

Claims (6)

An insulating tube comprising at least one layer comprising a polyarylene sulfide resin as a main component, wherein at least one of the layers is a layer comprising a polyarylene sulfide resin having a melting point of 275 ° C. or lower. The insulating tube according to claim 1, wherein the insulating tube is made of a polyarylene sulfide film. The insulating tube according to claim 2, wherein the polyarylene sulfide film is biaxially stretched. The insulating tube according to claim 2, wherein the polyarylene sulfide film has a constitution of two or more layers. The insulating tube according to claim 1, wherein the insulating tube has a thickness of 25 to 500 μm. The insulating tube according to claim 1, wherein a partial discharge start voltage in terms of 100 μm after the heat treatment at 150 ° C./1000 hours is 1000 V or more.