JP2006117872A - Copolyester and method for producing heat-shrinkable tube using the copolyester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide one kind of copolyester, and to provide a method for producing a heat-shrinkable tube using the copolyester. <P>SOLUTION: This thermoplastic copolyester is formed by increasing an intrinsic viscosity thereof to a range of 0.85-1.05 dl/g through solid polymerization, and therefore applicable to production of the heat-shrinkable tube. The method for producing the heat-shrinkable tube comprises using the thermoplastic copolyester, molding the copolyester into a tubular material through melt extrusion, and subjecting the tubular material to blowing, diameter expansion, and drawing, so as to form the material into the polyester heat-shrinkable tube, wherein the heat-shrinkable tube has a heat shrinkage percentage in a machine direction (MD) of not more than 15% and a heat shrinkage percentage in a transverse direction (TD) of not less than 40%. Further, the heat-shrinkable tube is useful for and applicable to a coating for various kinds of conductors and an external insulating film for the various kinds of the conductors. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a modified thermoplastic copolyester, in particular, a method for producing a heat shrinkable tube using the copolyester, and the produced heat shrinkable tube has an appropriate heat shrinkage rate and good heat resistance after heat treatment, Thermoplastic that has chemical resistance and heat deterioration resistance, can maintain close contact with the object to be coated even after overheating at high temperature, has no phenomenon such as expansion and loosening and wrinkles, and can be used for insulation coating of electronic parts Concerning copolyester.

  Typical electrically insulated heat-shrinkable tubes have used PVC as a material for a long time, but with the trend of prohibiting the use of PVC, countries such as Europe and Japan already require the use of PVC for materials in electrical facilities. It became so.

For this reason, a known technique (Patent Document 1) shows a method of manufacturing a heat-shrinkable tube used for coating a capacitor using a kind of polyester and the polyester. The polyester shown here is a blend of 20 to 70 weight percent polyethylene terephthalate (PET) and 30 to 80 weight percent copolyester, and the copolyester has a high purity of 65 to 95 weight percent based on the diol component. It is obtained by reacting terephthalic acid (PTA) with 5-35 weight percent isophthalic acid (IPA) and ethylene glycol (EG). At the same time, the polyester shown here produces an unstretched tube by melt extrusion, immediately cools it, and then heats it again to 72-98 ° C., and the longitudinal axis (MD) stretch ratio is 1.01-1. Biaxial stretching is simultaneously performed at 4 times and a transverse axis (TD) stretching ratio of 1.3 to 2.2 times, and then the stretched heat-shrinkable tube is cooled and wound. The heat-shrinkable tube manufactured by the patented technology has no crystallinity exceeding 20%, and when this heat-shrinkable tube is placed in hot water at 98 ± 2 ° C. for 10 seconds, the shrinkage rate in the vertical direction is between 5 and 26%. Yes, the radial shrinkage is at least 25%. Further, when the heat shrinkable tube is heat shrunk and coated on the capacitor, the appearance of the heat shrinkable tube is complete and free from defects.
US Pat. No. 5,368,811

In the known technique (Patent Document 2), a manufacturing method in which the printability of the polyester heat-shrinkable tube is improved is presented. The polyester shown here is a mixture of 20 to 99.5 weight percent of a polyester containing polyethylene terephthalate and 0.5 to 50 weight percent of a copolyester containing polyethylene glycol, and the content of polyethylene glycol is 0% of the copolyester. .1 to 4 weight percent. At the same time, according to the patented technology, the manufactured heat-shrinkable tube is 100-800 W. Corona discharge treatment is performed at min / m ² , thereby achieving the effect of improving the printability of the polyester heat-shrinkable tube.
US Pat. No. 5,403,454

In the known technique (Patent Document 3), polyethylene sulfoxide is used as a material, an unstretched tube is produced by a melt extrusion method, and the longitudinal axis (MD) stretch ratio is 1.05 to 4.4 at a temperature of 85 to 108 ° C. When the heat shrinkable tube thus produced is biaxially stretched 5 times and the transverse axis (TD) draw ratio is 1.3 to 4.5 times and placed in hot water at 100 ° C. for 30 seconds, the shrinkage ratio in the radial direction is 25 to 25%. Between 80%. In addition, the capacitor is inserted into this heat shrinkable tube and heated at 180 ° C. for 20 seconds so that the heat shrinkable tube shrinks due to heat and tightly covers the capacitor, and this capacitor is placed in an oven at 160 ° C. and after 3 minutes. Even when taken out, the heat shrinkable tube does not show defects such as wrinkles, expansion, peeling or deformation.
US Pat. No. 5,718,953

In the known technique (Patent Document 4), a kind of polyester and a heat-shrinkable tube for covering a capacitor made of the polyester are presented. One type of polyester presented here is a blend of 80-99 weight percent copolymerized polyester and 1-20 weight percent polybutylene terephthalate, the copolymerized polyester comprising 1-15 mole percent polyethylene naphthalate (PEN). ) And 85 to 90 mole percent of polyethylene terephthalate (PET), and its intrinsic viscosity is 0.65 to 1.0 dl / g. At the same time, the polyester shown here produces an unstretched tube by melt extrusion, which is immediately cooled and subsequently reheated to exceed the glass transition temperature to a longitudinal axis (MD) draw ratio of 1 to 1.5. The biaxial stretching is simultaneously performed at a double and horizontal axis (TD) draw ratio of 1.7 to 2.5 times, and then the stretched heat-shrinkable tube is cooled and wound. When the heat-shrinkable tube thus produced is placed in hot water at 98 ° C. for 30 seconds, its longitudinal shrinkage is between 5 and 15%, and its radial shrinkage is between 40 and 60%. Further, after inserting the capacitor into this heat shrinkable tube and heating it at 260 to 280 ° C. for 8 seconds to heat shrink and tightly coat the capacitor, this capacitor was put in an oven at 170 ± 5 ° C. and passed for 3 minutes. Furthermore, even if it puts in 100 +/- 2 degreeC hot water for 10 minutes, this heat-shrinkable tube does not have defects, such as a wrinkle, expansion | swelling, peeling, and a deformation | transformation.
US Pat. No. 6,528,133

Although the above-mentioned known techniques have already shown that a heat-shrinkable tube can be manufactured from a polyester material, US Pat. No. 5,368,811 and US Pat. No. 5,403,454 disclose two types of A mixed composition of different forms of polyester is used, and the patent does not mention the heat degradation characteristics after completing the capacitor coating with a heat shrink tube. Also, US Pat. No. 6,528,133 uses a mixed composition of two different forms of polyester, and the conditions for measuring heat resistance in the patent are as follows: 170 ± 5 ° C. in an oven for 3 minutes. Leave it in a hot water of 100 ± 2 ° C. for 10 minutes. In another US Pat. No. 5,718,953, heat-shrinkable tubes are manufactured using polyethylene sulfide, which has good heat-resistant deterioration characteristics, but is expensive.
In addition, as the demands for the functions of electronic products increase, the requirements for component standards have become stricter, and the requirements such as heat resistance and heat deterioration resistance of capacitors have further increased.

  The main object of the present invention is to show a modified thermoplastic copolyester and its composition and properties. By completing the modification in the synthesis reaction stage of polycondensation, the polyester resin material of the present invention can be made into a random copolyester, and when it is used for the production of polyester heat-shrinkable tubes, heat-shrinkable tubes are produced by known techniques. This eliminates the inconvenience of having to use a mixture of different forms of polyester, and avoids compatibility problems between different forms of polyester, which makes it easy to obtain and cost However, it has the advantages of being inexpensive and easy to process.

Another main object of the present invention is to produce a copolyester heat shrinkable tube employing the thermoplastic copolyester of the present invention. The surface of the object can be coated by the method of heat shrinkage, and when the object is coated by heat shrinkage, it has an excellent effect that it adheres tightly on the object and has a perfect appearance and no defects, and the shape of the coated object itself And the effect of protection and insulation of the coated object can be achieved. In particular, the heat-shrinkable tube and the completely coated object are both placed in an oven at 180 ± 2 ° C. and heated for 30 minutes, and even if heated in an oven at 105 ± 2 ° C. for 180 minutes, they are completely tight. A uniform coating and prevent deformations such as wrinkles, protrusions, loosening, peeling, rupturing and wrinkling.
Furthermore, after the object is coated with a heat shrinkable tube manufactured using the thermoplastic copolyester of the present invention, the heat shrinkable tube is in close contact with the surface of the object to be coated even after severe heat deterioration measurement. It can be maintained so that deformations such as wrinkles, protrusions, loosening, peeling, rupture and twisting do not occur.

  In the present invention, when synthesizing the thermoplastic copolyester of the present invention, inorganic particles having a specific particle size may be added at the stage of the melt polycondensation reaction. Its secondary purpose is to make it undissolvable and applicable to high-speed heat shrink coating operations.

  The present invention provides a method for producing a heat-shrinkable tube using the copolyester of the present invention. The polyester heat-shrinkable tube of the present invention protects the object to be coated and achieves the insulating effect of the object to be coated. With two secondary objectives. Therefore, the use of the polyester heat-shrinkable tube of the present invention is a heat-shrinkable tube that can be applied to an electronic component, covers the electronic component, and makes the electronic component have an insulating effect, for example, insulation of an aluminum capacitor. It can be a coated heat shrinkable tube or the like.

  A conventional polyester synthesis method can be used for the synthesis of the copolyester shown in the present invention. For example, a PTA manufacturing process or a DMT manufacturing process. When the PTA production process is selected, no ester is required because the esterification reaction is directly performed using dicarboxylic acid and diol as raw materials. A mixed gas of ethylene glycol and water generated in the esterification process is separated by a distillation tower, and then ethylene glycol is circulated and injected into an esterification tank, and a polymerization catalyst is injected before the esterification reaction is completed. The catalyst may be selected from an antimony catalyst, a germanium catalyst, a titanium catalyst, or a mixed form thereof, and a stabilizer containing phosphorus element such as phosphoric acid is injected before the esterification is completed and the polymerization reaction is started. Also, inorganic particles such as titanium dioxide, barium sulfate, calcium carbonate, silicon dioxide, etc. are injected at this stage. Then, a polymerization reaction is performed in a vacuum environment. When the viscosity of the copolyester reaches 0.6 dl / g or more, it is taken out and made into sliced ester grains.

  When the DMT production process is selected, a transesterification reaction is performed with a diol using an ester form of dicarboxylic acid as a raw material. A transesterification catalyst such as manganese acetate is injected before starting the reaction. Methanol generated during the transesterification reaction is not injected again into the transesterification tank after separation in the distillation column. When 98% of the theoretical methanol yield is removed and collected, a stabilizer containing elemental phosphorus is injected to lose the activity of the transesterification catalyst. Thereafter, the catalyst is selected and injected from an antimony catalyst, a germanium catalyst, a titanium catalyst, or a mixed catalyst thereof, and then a polymerization reaction is performed in a vacuum environment. When the viscosity of the copolyester reaches 0.6 dl / g or more, the copolyester is taken out and cooled rapidly to make a sliced ester grain.

  In both the PTA production process and the DMT production process, the synthesized ester particles must be further subjected to a solid state polymerization reaction. As a result, the intrinsic viscosity is increased to a range of 0.85 to 1.05 dl / g to obtain the copolyester shown in the present invention.

When synthesizing the copolyester shown in the present invention in the PTA production process, the main component of the dicarboxylic acid is high-purity terephthalic acid, and it contains isophthalic acid equivalent to 5 to 15 mole percent of the dicarboxylic acid component. It may contain other subcomponents such as 2,6-naphthalenecarboxylic acid or its ester form, but this component is not absolutely necessary for the present invention and its content comprises 8 mole percent of the copolyester. Do not exceed.
Further, when the copolyester shown in the present invention contains an isophthalic acid content lower than 5 mole percent of the dicarboxylic acid component, the heat-shrinkable tube produced thereby is placed in an oven at 180 ° C. for 30 minutes, and then heat-shrinkable. When the surface of the tube swells and loosens to form a deformation phenomenon, and the content of isophthalic acid is higher than 18 mole percent of the dicarboxylic acid component, the copolyester becomes amorphous and undergoes solid state polymerization. Thus, the intrinsic viscosity of the copolyester cannot be increased.

  The diol component composing the copolyester shown in the present invention is mainly ethylene glycol. The diol component may also contain at least one other diol component such as diethylene glycol, cyclohexanedimethanol, propylene glycol, 2,2-dimethyl-1,3-propanediol (NPG) (neopentyl glycol), 2- You can choose one from the group consisting of butyl-2-ethyl-1,3-propanediol (BEPG) and butylene glycol, but these diol subcomponents are not essential components and you choose to add diol subcomponents The content does not exceed 10 mole percent with respect to the total diol component. If it exceeds 10 mole percent, the copolyester becomes amorphous, and the intrinsic viscosity of the copolyester cannot be increased by solid-state polymerization.

  When synthesizing the copolyester of the present invention, as a preferred production method, inorganic particles are added before the end of the melt condensation polymerization, and as a more preferred production method, inorganic particles are injected in advance before the start of the condensation polymerization. deep. The inorganic particles used in the present invention can be selected from one or more of the group consisting of titanium dioxide, barium sulfate, calcium carbonate, silicon dioxide or mixtures thereof. As a preferred production method, titanium dioxide or barium sulfate is added. Furthermore, the addition amount of the inorganic particles should be 0.005 to 0.5 weight percent with respect to the weight of the copolyester, and the particle size of the inorganic particles should be smaller than 1 micrometer (μm), 0.1 to 0 Preferably it is between 5 micrometers. When synthesizing the copolyester of the present invention, the purpose of adding the above-mentioned inorganic particles in the melt-condensation polymerization stage is to make it easier to unwind after winding the heat-shrinkable tube manufactured in the present invention. Therefore, there is an advantage that it can be applied to a high-speed shrink coating operation.

  The copolyester of the present invention may further contain other additives according to actual processing needs. For example, flame retardants, colorants, antioxidants, lubricants, ultraviolet absorbers, antistatic agents and the like.

  The precursor of the copolyester of the present invention obtained by melt polymerization further undergoes a solid state polymerization reaction to increase the intrinsic viscosity within the range of 0.85 to 1.05 deciliter / gram. When the intrinsic viscosity is lower than 0.85 deciliter / gram, the thickness is not uniform when manufacturing the heat-shrinkable tube by melt extrusion, and when the intrinsic viscosity is higher than 1.05 deciliter / gram, for example, 150 micrometers or less. Thin heat-shrinkable tubes cannot be manufactured.

  The copolyester of the present invention is analyzed for thermal properties with a differential scanning calorimeter (DSC). The copolyester is rapidly cooled after complete melting, and again measured for its glass transition temperature (Tg), crystallization temperature (Tch) and melting point (Tm) at a temperature increase rate of 20 ° C./min. The glass transition temperature is preferably between 65 and 75 ° C, and the crystallization temperature is preferably higher than 170 ° C or almost no crystallization temperature. The heat of crystallization is preferably less than 15 joules / gram or non-crystalline, the melting point is preferably between 210-250 ° C., and the heat of fusion is preferably less than 15 joules / gram.

Hereinafter, a method and a process for producing a heat shrinkable tube from the copolyester shown in the present invention will be described.
In the dehumidified air at 150 to 170 ° C., the copolyester shown in the present invention is dried for 4 to 6 hours, the dried copolyester is continuously melted in an extruder, and the melting temperature is set higher than the melting point (Tm), After the molten resin body is extruded and passed through the nozzle of the annular nozzle, it is immediately cooled with cold air or cold water to be molded into a cylindrical unstretched tube, and this unstretched tube is conveyed by a feed roller to hot water or infrared Heat with a lamp, heat up to the glass transition temperature or higher, pass compressed air into the inside and blow-expand the unstretched tube to form a tube with a predetermined diameter, and further blow-stretch with another cooling pinching roller Pull out the tube and wind it up to make a heat shrinkable tube. This heat-shrinkable tube is stretched in the radial direction (TD, Transverse Direction) by blow stretching, and stretched in the longitudinal direction (MD, Machine Direction) due to the speed difference between the two front and rear rollers. Since the tube is cooled immediately after being stretched in the biaxial direction, the tube is cooled and contracts in the radial direction (TD) and the longitudinal direction (MD). This achieves the purpose of coating the object. The heat-shrinkable tube of the present invention has a thickness of 20 to 200 micrometers and a pipe diameter circumference of 4 to 300 mm as a preferred embodiment.

The heat shrinkable tube made of the copolyester shown in the present invention has a machine direction (MD) stretch ratio equal to the ratio of the pulling speed of the contracted tube after stretching and the conveying speed of the unstretched tube. The radial (TD) draw ratio is equal to the ratio of the tube diameter after blow expansion to the diameter of the unstretched tube.
When producing a heat-shrinkable tube with the copolyester shown in the present invention, the temperature of stretching diameter is preferably between 85 ° C. and 105 ° C., and the ratio of machine direction (MD) stretching is between 1.0 and 3.0 times. The stretching ratio in the radial direction (TD) is preferably 1.3 to 4.5 times.

  When the heat-shrinkable tube produced in the present invention is taken out of hot water at 100 ° C. for 30 seconds and then taken out, its longitudinal direction (MD) heat shrinkage rate is preferably 5% to 15%. If the longitudinal heat shrinkage rate is lower than 5%, the edges of the heat shrinkable tube and the object to be coated are not tightly coated. If the longitudinal heat shrinkage rate is higher than 15%, the heat shrinkage tube is deformed when covered. Moving. The radial direction (TD) heat shrinkage rate is preferably higher than 35%. If the radial direction (TD) heat shrinkage rate is lower than 35%, the coating tightness of the heat shrinkable tube may be insufficient.

  After the heat-shrinkable tube manufactured in the present invention is coated on the object to be coated, it is heated to a temperature exceeding 200 ° C. and lower than the melting point of the copolyester to shrink the tube, thereby completing the object coating.

  After the heat-shrinkable tube of the present invention was completely coated, it was placed in an oven at 180 ° C. for 30 minutes and after being heated in an oven at 105 ° C. for 3 hours. It remains in close contact with the surface of the object, and deformation phenomena such as wrinkles, protrusions, loosening, peeling, bursting, and twisting do not occur.

  When the heat-shrinkable tube manufactured with the copolyester shown in the present invention is washed with acetone after printing, the printed font after washing can be prevented from collapsing.

Examples and comparative examples are given below to further clarify the technical contents of the present invention. The scope of rights of the present invention is not limited to the scope of the examples.
Example 1
10.27 weight parts of bis-2-hydroxyethyl terephthalate (BHET) is taken, 0.432 weight parts of isophthalic acid (IPA) and 3.243 weight parts of ethylene glycol (EG) are placed in the reaction vessel, When the raw material temperature reaches 190 ° C. or higher, the esterification reaction starts, the reaction pressure is 1.0 to 1.5 kg / cm ² , the reaction is performed for 180 minutes to achieve an esterification rate of 95% or higher, and 0.035 wt. Titanium dioxide, stabilizer phosphoric acid, and catalytic antimony acetate are added, and vacuum is started. The material temperature is set to 250 to 280 ° C. in a vacuum environment of 1 torr, the reaction is performed to a viscosity of 0.60 deciliter / gram or more, the material is discharged and cooled to form cylindrical amorphous raw particles. Subsequently, this raw granule is put into a solid state polymerization reactor, the temperature of the ester granule is set to 190 to 220 ° C., and the viscosity of the ester granule is increased to 0.95 deciliter / gram in a nitrogen atmosphere or a vacuum environment. .
The formed ester grains are dried with dehumidified air at 150 ° C. for 4 hours, melt extruded at 250 to 270 ° C. with an extruder, and formed into a hollow columnar unstretched raw pipe through a ring nozzle, and this raw pipe is immediately cooled. The feed pipe (Feed Roller) with the rotation speed set to 100 rpm is allowed to pass through the water tank and then the feed pipe is passed through the heater so that the temperature of the feed pipe reaches 90-100 ° C. Pressurized air is passed inside, the diameter of the original pipe is blown and expanded to a tube that is 1.3 times the diameter of the original pipe, and the expanded tube is pulled out by a pulling roller (Nip Roller) with a rotation speed of 105 rpm. In this way, the heat shrinkable tube is formed.
Subsequently, a series of measurements are performed on the manufactured heat shrinkable tube. Measurement of blow stability, measurement of appearance coating integrity after heating in an oven at 180 ° C. for 30 minutes, measurement of appearance coating integrity after heating in an oven at 105 ° C. for 3 hours, measurement of wound heat-shrinkable tube Including the measurement of unwinding ease and the measurement of acetone-cleaning print integrity, the details of the results are shown in (Table 1).

Example 2
According to the method of Example 1, except that 9.73 parts by weight of bis-2-hydroxyethyl terephthalate (BHET) and 0.864 parts by weight of isophthalic acid (IPA) were placed in the reactor, reacted, and melted. After polymerization is complete, solid state polymerization is performed to increase the viscosity to 0.97 deciliter / gram. Subsequently, each item was measured on the manufactured heat-shrinkable tube, and the results are shown in (Table 1).

Example 3
According to the method of Example 1, except that 9.186 parts by weight of bis-2-hydroxyethyl terephthalate alone (BHET) and 1.296 parts by weight of isophthalic acid (IPA) were placed in the reactor, reacted, and melted. After polymerization is complete, solid state polymerization is performed to increase the viscosity to 1.05 deciliter / gram. When the polyester of this example is subjected to solid-state polymerization, the heating conditions for the temperature increase slower than those of Example 1 are necessary, otherwise a lump is generated. Subsequently, each item was measured on the manufactured heat-shrinkable tube, and the results are shown in (Table 1).

Example 4
According to the method of Example 1, except that only 10.81 parts by weight of bis-2-hydroxyethyl terephthalate (BHET) is placed in the reactor and reacted. No IPA was added, 2.91 parts by weight of ethylene glycol (EG) and 0.552 parts by weight of 2-butyl-2-ethyl-1,3-propanediol (2-Butyl-2-Ethyl-1,3- Propanediol (abbreviation BEPG) is added and after completion of melt polymerization, solid state polymerization is performed to increase the viscosity to 0.95 deciliter / gram. Subsequently, each item was measured on the manufactured heat-shrinkable tube, and the results are shown in (Table 1).

Example 5
According to the method of Example 1, except that 10.81 wt.% Of bis-2-hydroxyethyl terephthalate alone (BHET) was placed in the reactor to react (without adding IPA), 2.91 wt. Glycol (EG) and 0.750 weight part of cyclohexane dimethanol (abbreviated as CHDM) are added to complete the melt polymerization, followed by solid state polymerization to increase the viscosity to 0.95 deciliter / gram. Subsequently, each item was measured on the manufactured heat-shrinkable tube, and the results are shown in (Table 1).

Example 6
Follow the procedure of Example 2, but do not add titanium dioxide (TiO ₂ ). After completion of melt polymerization, solid state polymerization is performed to increase the viscosity to 0.95 deciliter / gram. Subsequently, each item was measured on the manufactured heat-shrinkable tube, and the results are shown in (Table 1).

Example 7
According to the method of Example 1, except that 9.94 weight parts of bis-2-hydroxyethyl terephthalate (BHET) and 0.692 weight parts of isophthalic acid (IPA) were placed in the reactor, reacted, and melted. After polymerization is complete, solid state polymerization is performed to increase the viscosity to 0.85 deciliter / gram. Subsequently, each item was measured on the manufactured heat-shrinkable tube, and the results are shown in (Table 1).

Comparative Example 1
According to the method of Example 1, except that 10.81 wt.% Of bis-2-hydroxyethyl terephthalate alone (BHET) is taken, IPA is not added, and 3.243 wt. Of ethylene glycol (EG) is added to the reactor. It is allowed to react inside and after completion of melt polymerization, solid state polymerization is performed to increase the viscosity to 0.95 deciliter / gram. Subsequently, each item was measured on the manufactured heat-shrinkable tube, and the results are shown in (Table 1).

Comparative Example 2
According to the method of Example 1, except that 10.537 parts by weight of bis-2-hydroxyethyl terephthalate alone (BHET), 0.216 parts by weight of isophthalic acid (IPA) and 3.243 parts by weight of ethylene glycol (EG). The reaction is conducted in a reactor, and after completion of melt polymerization, solid state polymerization is performed to increase the viscosity to 0.95 deciliter / gram. Subsequently, each item was measured on the manufactured heat-shrinkable tube, and the results are shown in (Table 1).

Comparative Example 3
According to the method of Example 1, except that 8.970 parts by weight of bis-2-hydroxyethyl terephthalate (BHET), 1.470 parts by weight of isophthalic acid (IPA) and 3.243 parts by weight of ethylene glycol (EG). The reaction is conducted in a reactor and melt polymerization is performed to increase the viscosity to 0.75 deciliter / gram. Since the polyester obtained in this way is remarkably agglomerated during solid state polymerization, it is formed into a heat-shrinkable tube using a copolyester that does not undergo solid state polymerization. The drying temperature before the ester grain melt processing is set to 70 ° C. Subsequently, each item was measured on the manufactured heat-shrinkable tube, and the results are shown in (Table 1).

Comparative Example 4
According to the method of Example 5, except that 10.81 parts by weight of bis-2-hydroxyethyl terephthalate (BHET) was placed in the reactor to react, and IPA was not added, but 2.260 parts by weight of ethylene glycol (EG ) And 2.250 parts by weight of cyclohexane dimethanol (abbreviated as CHDM) are reacted in the reactor and melt polymerized to increase the viscosity to 0.80 deciliter / gram. Since the polyester obtained in this way is remarkably agglomerated during solid state polymerization, it is formed into a heat-shrinkable tube using a copolyester that does not undergo solid state polymerization. The drying temperature before the ester grain melt processing is set to 70 ° C. Subsequently, each item was measured on the manufactured heat-shrinkable tube, and the results are shown in (Table 1).

（表１）の個別物質含有量は、全てコポリエステルに対する含有量である。
表中の符号は、◎良好、△普通、×不良。 Results According to the results shown in Table 1, the copolyesters of Examples 1 to 7 were produced by increasing the intrinsic viscosity in the range of 0.85 to 1.05 deciliter / gram by solid state polymerization. The heat-shrinkable tube has a blow-stable surface, an appearance coating integrity surface after heating in an oven at 180 ° C for 30 minutes, an appearance coating integrity surface after heating in an oven at 105 ° C for 3 hours, and winding. The results were excellent in all aspects of the ease of unwinding of the heat-shrinkable tube and the acetone-cleaning printing completeness.

The individual substance contents in Table 1 are all contents relative to the copolyester.
The symbols in the table are ◎ Good, △ Normal, × Poor.

Claims (9)

  A copolyester obtained by reacting a dicarboxylic acid or ester thereof with a diol, in which the diol component is ethylene glycol (EG) and the main component of the dicarboxylic acid is high-purity terephthalic acid (PTA) or an ester thereof And containing 5 to 15 mole percent of isophthalic acid (IPA) or an ester thereof, and the copolyester has an intrinsic viscosity of 0.85 to 1.05 deciliter / gram via solid state polymerization reaction. A heat-shrinkable tube copolyester characterized by being raised to   The components of the diol used are the main components ethylene glycol (EG) and diethylene glycol, cyclohexanedimethanol, propylene glycol, 2,2-dimethyl-1,3-propanediol (NPG) (neopentyl glycol), 2-butyl-2 -Containing at least one diol subcomponent group consisting of -ethyl-1,3-propanediol (BEPG) and butylene glycol, and the diol subcomponent content should not be higher than 10 mole percent of the total diol components The heat-shrinkable tube copolyester according to claim 1.   At least one of inorganic particle groups consisting of titanium dioxide, barium sulfate, calcium carbonate and silicon dioxide is added in the melt reaction stage of the copolyester synthesis, and the content of the inorganic particles is 0.005 to the copolyester weight. The heat-shrinkable tube copolyester according to claim 1 or 2, wherein the inorganic particle has a particle size of less than 1 micrometer (µm).   The heat-shrinkable tube copolyester according to claim 3, wherein the inorganic particles have a particle size of 0.1 to 0.5 micrometers (µm).   A copolyester having an intrinsic viscosity of 0.85 to 1.05 deciliter / gram is selected as a raw material, an unstretched tube is formed through melt extrusion, and the unstretched tube is further heated to the glass transition temperature or higher, and then stretched in the machine direction. And gas expansion and expansion in the radial direction to form a heat shrinkable tube having a longitudinal draw ratio of 1.0 to 3.0 times and a radial draw ratio of 1.3 to 4.5 times. A method for producing a heat-shrinkable tube, characterized in that the shrinkage ratio in the longitudinal direction when placed in water is 5% to 15% and the shrinkage ratio in the radial direction exceeds 35%.   To the copolyester raw material to be selected, at least one of inorganic particle groups consisting of titanium dioxide, barium sulfate, calcium carbonate and silicon dioxide is added, and the content of inorganic particles is 0.005 to 0.5 of the weight of the copolyester. 6. The method for producing a heat-shrinkable tube according to claim 5, wherein the weight percentage is such that the particle size of the inorganic particles is smaller than 1 micrometer (μm).   The manufactured heat-shrinkable tube is heat-shrink-coated on the object, and then heated at 180 ° C. for 30 minutes, so that the heat-shrinkable tube can completely maintain the object-covered, wrinkles, protrusions, loosening, peeling, bursting 7. The method for producing a heat-shrinkable tube according to claim 5 or 6, wherein there is no deformation phenomenon such as twisting.   The manufactured heat-shrinkable tube is heat-shrinkage coated on the object, and then heated at 105 ° C. for 180 minutes, so that the heat-shrinkable tube can completely maintain the object coating, and wrinkles, protrusions, loosening, peeling, bursting 7. The method for producing a heat-shrinkable tube according to claim 5 or 6, wherein there is no deformation phenomenon such as twisting.   The manufactured heat-shrinkable tube can be easily unwound after unwinding by adding inorganic particles of a specific particle size during the melt polycondensation reaction during the synthesis of thermoplastic copolyester. The method for producing a heat-shrinkable tube according to claim 6, wherein