WO2019194172A1

WO2019194172A1 - Heat-shrinkable tube

Info

Publication number: WO2019194172A1
Application number: PCT/JP2019/014611
Authority: WO
Inventors: 敏脇中; 光藤澤
Original assignee: グンゼ株式会社
Priority date: 2018-04-02
Filing date: 2019-04-02
Publication date: 2019-10-10
Also published as: JPWO2019194172A1; JP7175307B2

Abstract

Provided is a novel heat-shrinkable tube which can thermally shrink to cover a surface of a member, the tube being capable of exhibiting, in a low-temperature environment, a sufficiently high degree of thermal shrinkage for covering a surface of a member. The heat-shrinkable tube has been formed from a thermoplastic resin comprising a polymer having a repeating unit represented by general formula (A), and has a wall thickness of 600 μm or larger, the wall thickness having a longitudinal-direction fluctuation of 10% or less. The heat-shrinkable tube satisfies the relationships 5≤X and 0.9≤Y/X≤1.1, where X (%) is the degree of thermal shrinkage through 5-minute heating in a gas phase having a temperature of 150°C and Y (%) is the degree of thermal shrinkage through 5-minute heating in a gas phase having a temperature of 300°C. –(Ar¹-C(=O)-Ar²-O-Ar³-O)- (A) [In general formula (A), groups Ar¹, Ar², and Ar³ each independently represent an optionally substituted aromatic hydrocarbon group.]

Description

Heat shrinkable tube

The present invention relates to a heat-shrinkable tube, a method for producing a heat-shrinkable tube, a method for producing a heat-resistant member, and a method for producing a covering member.

Conventionally, covering members made of heat-resistant resin have been used in various fields. Among the heat-resistant resins, the fluorine-based resin is excellent not only in heat resistance but also in chemical resistance, and is therefore used in a wide range of fields as a covering member that improves the heat resistance of the member.

On the other hand, although the fluorine-based resin is excellent in heat resistance, it is inferior in wear resistance, and is not suitable for a covering member that requires high wear resistance. As a resin having excellent wear resistance in addition to heat resistance, aromatic polyether ketones typified by polyether ether ketone (PEEK) are known.

For example, Patent Document 1 discloses that a conductive core material (that is, a member) formed in a rod shape or a cylindrical shape and a polyether ether ketone is formed into a cylindrical shape, and the core material inserted has a higher degree of crystallinity. An electrode bar for an electrostatic capacity type level meter having an insulating cylinder (that is, a covering member) that contracts and adheres to each other and has excellent heat resistance and durability is disclosed.

JP 2009-192485 A

As described above, aromatic polyether ketones typified by polyether ether ketone (PEEK) are characterized by excellent wear resistance in addition to heat resistance. Moreover, such an aromatic polyether ketone can also be used as a covering member that covers the surface of a member by being formed into a tube shape and thermally contracted.

However, conventionally, the aromatic polyetherketone molded into a tube shape exhibits a high heat shrinkage ratio and covers the surface of the member at a high temperature around the melting point of the aromatic polyetherketone (for example, polyetherether). If it is a ketone, it is necessary to heat it to about 340 ° C. In particular, when a thick-walled aromatic polyetherketone tube is sufficiently heat-shrinked, sufficient heating in a high-temperature environment is required.

For this reason, conventional aromatic polyether ketone tubes are not suitable as covering members for members that are thermally deformed in a high temperature environment near the melting point of aromatic polyether ketone.

Further, in the case of a member that is easily thermally expanded, when the aromatic polyetherketone tube is thermally contracted by heating to a high temperature near the melting point of the aromatic polyetherketone, the member is greatly expanded. For this reason, when the member coat | covered with the coating member which consists of aromatic polyether ketone falls to use temperature, the adhesiveness of a coating member and a member will become inadequate. In order to avoid such a situation, increasing the thermal shrinkage rate of the aromatic polyetherketone tube causes the aromatic polyetherketone tube to break due to thermal expansion of the member at the temperature of use of the member. There is a problem that it is difficult to design the dimensions of the polyetherketone tube and members.

Furthermore, the heat-shrinkable tube is also required to have a high shape accuracy with suppressed variation in wall thickness.

Under such circumstances, the present invention is a heat-shrinkable tube that can heat-shrink to cover the surface of a member, and is heat-shrinkable enough to cover the surface of the member in a low-temperature environment (for example, about 150 ° C.). The main object is to provide a novel heat-shrinkable tube that can exhibit a high rate (for example, a heat shrinkage rate of 5% or more) and that suppresses variations in thickness.

The present inventor has intensively studied to solve the above-described problems of the prior art. As a result, a heat-shrinkable tube that can be heat-shrinkable to cover the surface of a member by forming the tube according to predetermined manufacturing conditions and then stretching the tube to cover the surface of the member in a low-temperature environment It has been found that a novel heat-shrinkable tube can be obtained that can exhibit a sufficient heat-shrink rate and further suppress variations in thickness.

More specifically, in the tube forming step, the thermoplastic resin constituting the tube is heated to a temperature of 340 ° C. or higher, and the formed tube formed into a tube shape by continuous melt extrusion molding is heated to a temperature of 130 to 160 ° C. After cooling to a temperature of 10 to 50 ° C. to obtain an unstretched tube, the unstretched tube is stretched, for example, even if the wall thickness is 600 μm or more, the temperature is 150 ° C. When the heat shrinkage rate when heated in the gas phase for 5 minutes is X% and the heat shrinkage rate when heated in the gas phase at 300 ° C. for 5 minutes is Y%, the following relationship is satisfied: Furthermore, when the thickness is measured at intervals of 5 mm for the range within 50 mm in the longitudinal direction as described later, [maximum thickness-minimum thickness] / average thickness Ratio calculated by value x 100 ( %) Is a variation in wall thickness, and this is measured at eight points in the circumferential direction at equal intervals, and the largest value is the variation in the wall thickness of the thermoplastic tube). We found that a tube was obtained.
5 ≦ X
0.9 ≦ Y / X ≦ 1.1

That is, this invention provides the invention of the aspect hung up below.
Item 1. The following general formula (A):
— (Ar ¹ —C (═O) —Ar ² —O—Ar ³ —O) — (A)
[In General Formula (A), the group Ar ¹ , the group Ar ² , and the group Ar ³ are each independently an aromatic hydrocarbon group that may have a substituent. ]
A heat-shrinkable tube formed of a thermoplastic resin containing a polymer having a repeating unit represented by:
The wall thickness is 600 μm or more,
Variation in the longitudinal direction of the wall thickness is 10% or less,
When the heat shrinkage rate when heated for 5 minutes in the gas phase at 150 ° C. is X% and the heat shrinkage rate when heated for 5 minutes in the gas phase at 300 ° C. is Y%, A heat-shrinkable tube that satisfies this relationship.
5 ≦ X
0.9 ≦ Y / X ≦ 1.1
Item 2. Item 2. The heat-shrinkable tube according to Item 1, wherein the degree of crystallinity after being placed in a gas phase at a temperature of 150 ° C for 5 minutes from an environment at a temperature of 25 ° C is 10% or less.
Item 3. Item 3. The heat-shrinkable tube according to

Item

1 or 2, wherein the degree of crystallinity after being placed in a gas phase at a temperature of 200 ° C for 5 minutes from an environment at a temperature of 25 ° C is 20% or more.
Item 4. Item 4. The heat-shrinkable tube according to any one of Items 1 to 3, wherein the heat-shrinkable tube is a cylindrical endless tube.
Item 5. The following general formula (A):
— (Ar ¹ —C (═O) —Ar ² —O—Ar ³ —O) — (A)
[In the general formula (1), the group Ar ¹ , the group Ar ² , and the group Ar ³ are each independently an aromatic hydrocarbon group that may have a substituent. ]
A thermoplastic resin containing a polymer having a repeating unit represented by the following is heated to a temperature of 340 ° C. or higher, and a molded tube formed into a tube shape by continuous melt extrusion molding is cooled to a temperature of 130 to 160 ° C. Further, a molding step of cooling to a temperature of 10 to 50 ° C. to obtain an unstretched tube,
Stretching the unstretched tube molded in the molding step to obtain a heat-shrinkable tube,
A method for producing a heat-shrinkable tube.
Item 6. Item 6. The method for producing a heat-shrinkable tube according to Item 5, wherein the wall thickness is 600 µm or more.
Item 7. Preparing a heat-shrinkable tube according to any one of Items 1 to 4,
Placing a member inside the heat shrinkable tube;
A shrinking step of coating the member with a heat shrinkable tube by heating the heat shrinkable tube to a temperature of 160 ° C. or less and causing heat shrinkage;
A method for producing a heat-resistant member.
Item 8. Preparing a heat-shrinkable tube according to any one of Items 1 to 4,
A shrinking step in which the heat-shrinkable tube is heated to a temperature of 160 ° C. or less and thermally contracted;
A method for manufacturing a covering member.

According to the present invention, a heat-shrinkable tube capable of thermally shrinking and covering the surface of a member, and having a heat shrinkage rate sufficient to cover the surface of the member (for example, heat) in a low temperature environment (for example, about 150 ° C.). A novel heat-shrinkable tube that can exhibit a shrinkage rate of 5% or more and that is also capable of suppressing variation in wall thickness can be provided. Furthermore, according to the present invention, the method for producing the heat-shrinkable tube, the method for producing a heat-resistant member in which the heat-shrinkable tube is thermally shrunk to cover the surface of the member, and the heat-shrinkable tube is heat-shrinked. A method for producing a covering member can also be provided.

1 is a schematic perspective view of a heat-shrinkable tube of the present invention. It is a schematic diagram for demonstrating the method to heat-shrink the heat-shrinkable tube of this invention, and to coat | cover a member.

The heat-shrinkable tube of the present invention is a heat-shrinkable tube formed of a thermoplastic resin containing a polymer having a repeating unit represented by the following general formula (A), and has a wall thickness of 600 μm or more. The thickness variation in the longitudinal direction was 10% or less, and the heat shrinkage rate when heated for 5 minutes in a gas phase at a temperature of 150 ° C. was X%, and the film was heated for 5 minutes in a gas phase at a temperature of 300 ° C. When the thermal contraction rate at the time is Y%, the relationship of 5 ≦ X and 0.9 ≦ Y / X ≦ 1.1 is satisfied.
— (Ar ¹ —C (═O) —Ar ² —O—Ar ³ —O) — (A)
[In General Formula (A), the group Ar ¹ , the group Ar ² , and the group Ar ³ are each independently an aromatic hydrocarbon group that may have a substituent. ]

<Measurement of thickness variation>
In the present invention, the variation (%) in the thickness of the heat-shrinkable tube is calculated by the following equation when the thickness is measured at intervals of 5 mm in a range within 50 mm in the longitudinal direction of the heat-shrinkable tube. It is a value, and the variation in thickness is measured at eight locations at equal intervals in the circumferential direction of the heat-shrinkable tube, and the largest value is defined as the variation in thickness of the thermoplastic tube of the present invention. In addition, it is preferable to measure about 10 or more places, respectively, so that the thickness measurement location may prepare a heat-shrinkable tube having a length in the longitudinal direction of 50 mm or less, and be 5 mm apart in each longitudinal direction. For example, for a heat-shrinkable tube having a length of 50 mm in the longitudinal direction, the thickness variation is measured at 10 locations in each longitudinal direction (longitudinal direction at 8 locations at equal intervals in the circumferential direction), and the variation in thickness is expressed by Calculated, among the eight locations in the circumferential direction, the one with the largest variation value is defined as the variation (%) in the thickness of the heat-shrinkable tube.
Thickness variation (%) = (maximum thickness-minimum thickness) / average thickness x 100

Hereinafter, the heat-shrinkable tube of the present invention, the method for producing the heat-shrinkable tube, the method for producing a heat-resistant member in which the heat-shrinkable tube is thermally shrunk to cover the surface of the member, and the heat-shrinkable tube is heat-shrinkable A method for manufacturing the covered member will be described in detail.

1. Heat-shrinkable tube The heat-shrinkable tube of the present invention is a tubular member formed of a thermoplastic resin containing a polymer (aromatic polyether ketone) having a repeating unit represented by the following general formula (A). .
— (Ar ¹ —C (═O) —Ar ² —O—Ar ³ —O) — (A)

In the general formula (A), the group Ar ¹ , the group Ar ² , and the group Ar ³ are each independently an aromatic hydrocarbon group that may have a substituent. The group Ar ¹ , the group Ar ² , and the group Ar ³ are each independently preferably a phenylene group that may have a substituent.

In the case where the group Ar ¹ , the group Ar ² , and the group Ar ³ have a substituent, the substituent is not particularly limited, but a viewpoint of exhibiting a sufficient thermal contraction rate to cover the surface of the member in a low temperature environment Thus, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, a halogen atom, and the like are preferable. From the same viewpoint, each of the group Ar ¹ , the group Ar ² , and the group Ar ³ preferably has no substituent, and more preferably a phenylene group.

In the general formula (A), a polymer in which the group Ar ¹ , the group Ar ² , and the group Ar ³ are all phenylene groups is referred to as polyetheretherketone (hereinafter sometimes referred to as “PEEK”). It is a polymer. PEEK is usually produced by combining hydroquinone and benzophenone bonded to both ends using halogen as a substituent by a known nucleophilic substitution reaction. For example, it can be produced by a method of reacting 4,4′-difluorobenzophenone and hydroquinone in diphenyl sulfone (DPS) in the presence of an alkali metal carbonate such as potassium carbonate and / or sodium carbonate. There is also a production method in which benzophenone and a benzene ring having a ketone group bonded with chlorine as an electrophile at both ends are bonded by a known electrophilic substitution reaction using aluminum chloride or the like as a catalyst. By adjusting the composition ratio of the monomers constituting PEEK, those having a polymer terminal as a halogen atom such as a fluorine atom can be used, and those having a hydroxyl group can also be used. Moreover, the thing by which the terminal blocker was made to react with the terminal of PEEK, and the halogen terminal and the hydroxyl group terminal were substituted by inert substituents, such as a phenyl group, can also be used.

As a typical commercial product of PEEK, a product name “Victorex PEEK” series manufactured by Victorx is listed. Specifically, there are Victorex PEEK450G, 381G, 151G, 90G (trade name) and the like. In addition, as a commercial product of PEEK, VESTAKEEEP (trade name) of Daicel Degussa Co., Ltd. can be mentioned, and in addition, it is marketed by Solvay.

In the present invention, the polymer having the repeating unit represented by the general formula (A) may be a homopolymer composed of the above repeating unit, or may be a copolymer with another repeating unit. Good. In the case of a copolymer with other repeating units, from the viewpoint of exhibiting a sufficient heat shrinkage rate to cover the surface of the member in a low temperature environment, specific examples of other repeating units include the following general formula ( B) to (F).

— (Ar—C (═O) —Ar—O—Ar—X—Ar—O) — (B)
— (Ar—C (═O) —Ar—O) — (C)
— (Ar—C (═O) —Ar—C (═O) —Ar—O—Ar—X—Ar—O) — (D)
— (Ar—SO ₂ —Ar—O—Ar—O) — (E)
— (Ar—SO ₂ —Ar—O—Ar—X—Ar—O) — (F)

In the general formulas (B) to (F), the plurality of groups Ar are each independently the same as the groups Ar ¹ to Ar ^{3 in} the general formula (A). Examples of the group X include a single bond, an oxygen atom, a sulfur atom, a group —SO ₂ —, a group —CO—, or a divalent hydrocarbon group.

The thermoplastic resin forming the heat-shrinkable tube of the present invention may further contain another polymer in addition to the above polymer. Other polymers include polyetherimide (PEI), polyamideimide (PAI), polyetherketone (PEK), polyphenylsulfone (PPSU) and the like. These other polymers can be used for the purpose of reinforcing the above polymers, for example.

In the thermoplastic resin forming the heat-shrinkable tube of the present invention, the proportion of the polymer having the repeating unit represented by the general formula (A) is preferably about 50 to 100% by mass, more preferably 80 to 100%. About mass% is mentioned. The proportion of the other polymer is preferably about 0 to 20% by mass. When the ratio of the polymer to the other polymer in the thermoplastic resin is in such a range, a sufficient heat shrinkage rate can be exhibited in order to cover the surface of the member in a low temperature environment.

The melting point of the thermoplastic resin constituting the heat-shrinkable tube of the present invention is not particularly limited as long as it exhibits excellent heat resistance, but is preferably about 330 to 360 ° C., more preferably 340 to 350. A temperature of about ° C can be mentioned.

The heat-shrinkable tube of the present invention may contain a filler or an additive as necessary in addition to the above thermoplastic resin. The filler is added as necessary for the purpose of increasing the mechanical strength of the covering member obtained by heat-shrinking the heat-shrinkable tube of the present invention. As a filler, a well-known filler can be used and inorganic fillers, such as plate shape, flake shape, and scale shape, carbon black, etc. can be used.

Examples of inorganic fillers include scale-like or flake-like mica, mica, sericite, illite, talc, kaolinite, montmorillonite, smectite, vermiculite, plate-like or flaky titanium dioxide, potassium titanate and lithium titanate. Scaly titanate compounds, boehmite and the like. Among these, preferable examples of the filler include mica, sericite, illite, talc, kaolinite, montmorillonite, flaky titanate compound, boehmite and the like. Examples of carbon black include gas black, acetylene black, oil furnace black, thermal black, channel black, ketjen black, and carbon nanotube. A filler may be used individually by 1 type and may be used in combination of 2 or more types. When the heat-shrinkable tube of the present invention contains a filler, the filler content is preferably about 3 to 30% by mass.

Additives include antioxidants, thermal stabilizers, thermal conductors, plasticizers, light stabilizers, lubricants, antifogging agents, antiblocking agents, slip agents, crosslinking agents, crosslinking aids, adhesives, flame retardants, A dispersing agent etc. are mentioned. An additive may be used individually by 1 type and may be used in combination of 2 or more types. When the heat-shrinkable tube of the present invention contains an additive, the content of the additive is preferably about 30 to 60% by mass.

The shape of the heat-shrinkable tube of the present invention is cylindrical. From the viewpoint of heat-shrinking the heat-shrinkable tube of the present invention and suitably covering the surface of a cylindrical or columnar member, the tube is preferably a cylindrical endless tube.

The wall thickness M (see FIG. 1) of the heat-shrinkable tube of the present invention is 600 μm or more. In order to heat-shrink a conventional aromatic polyetherketone tube to cover the surface of a member, the temperature is close to the melting point of the aromatic polyetherketone (for example, about 340 ° C for polyetheretherketone). In particular, when an aromatic polyetherketone tube having a large thickness of 600 μm or more is sufficiently heat-shrinked, sufficient heating in a high-temperature environment is required. On the other hand, the heat-shrinkable tube of the present invention has a heat shrinkage rate sufficient to cover the surface of the member in a low-temperature environment (for example, about 150 ° C.) even though the wall thickness M is 600 μm or more. (For example, the thermal shrinkage rate is 5% or more).

The thickness M of the heat-shrinkable tube of the present invention is not particularly limited as long as it is 600 μm or more, and may be appropriately adjusted according to the use. However, the heat-resistant member (the heat-shrinkable tube of the present invention is heat-shrinked). The surface of the member is covered with a covering member), and the heat shrinkage rate is sufficient to cover the surface of the member in a low temperature environment while improving the heat resistance and wear resistance. From the viewpoint of suppressing an increase in the size of the heat-resistant member accompanying an increase in thickness, the thickness is preferably about 600 to 1400 μm, more preferably about 600 to 1000 μm.

The variation in the longitudinal direction of the thickness M of the heat-shrinkable tube of the present invention is not particularly limited as long as it is 10% or less, but is preferably 8% or less, more preferably 5% from the viewpoint of providing higher shape accuracy. The following are mentioned. In addition, the lower limit value of the variation in the longitudinal direction of the thickness M is 0%. The method for measuring the variation in the longitudinal direction of the thickness M of the heat-shrinkable tube is as described above.

Further, the length L of the tube (see FIG. 1) may be appropriately set according to the size of the member to be coated, and is not particularly limited, but may be about 1000 to 4000 mm, for example. The outer diameter N of the tube (see FIG. 1) may be set as appropriate according to the size of the member to be covered, and is not particularly limited, but may be about 50 to 300 mm, for example.

The heat-shrinkable tube of the present invention has a heat shrinkage rate of X% when heated in a gas phase at a temperature of 150 ° C. for 5 minutes, and a heat shrinkage rate when heated in a gas phase at a temperature of 300 ° C. for 5 minutes. When Y is Y%, the following relationship is satisfied.
5 ≦ X
0.9 ≦ Y / X ≦ 1.1

That is, the heat-shrinkable tube of the present invention has a large heat shrinkage rate X of 5% or more when heated in a gas phase at a temperature of 150 ° C. for 5 minutes, and the temperature with respect to the heat shrinkage rate X (%). The ratio (Y / X) of heat shrinkage Y (%) when heated in a gas phase at 300 ° C. for 5 minutes is in the range of 0.9 to 1.1, and at a low temperature of 150 ° C. The difference between the heat shrinkage rate X% and the heat shrinkage rate Y% at a high temperature of 300 ° C. is small. For this reason, the heat-shrinkable tube of the present invention can exhibit a sufficient heat shrinkage rate (for example, a heat shrinkage rate of 5% or more) to cover the surface of the member in a low temperature environment (for example, about 150 ° C.). it can. The heat-shrinkable tube of the present invention having characteristics different from those of the conventional aromatic polyetherketone tube is suitably produced by, for example, the method described in “2. Method for producing heat-shrinkable tube” described later. be able to.

In the present invention, the heat shrinkage rate X, Y (%) of the heat shrinkable tube is a value obtained by measuring as follows. The heat-shrinkable tube is transferred from an environment at a temperature of 25 ° C. to a thermostatic bath at a temperature of 150 ° C. in an atmospheric environment, heated for 5 minutes, and the heat shrinkage rate X% is measured. Separately, the heat-shrinkable tube is transferred from an environment at a temperature of 25 ° C. to a thermostatic bath at a temperature of 300 ° C. in an atmospheric environment, heated for 5 minutes, and the heat shrinkage rate Y% is measured. The heat shrinkage ratios X and Y (%) are calculated by the following calculation formulas for the heat shrinkable tubes before and after heat shrinkage, by cutting the tube in the longitudinal direction, opening the tube, and measuring the circumference of the tube with calipers. Ask for.
Heat shrinkage rate = (perimeter before heat shrink-circumference after heat shrink) / circumference before heat shrink x 100 (%)

In the present invention, the heat shrinkage ratio X% of the heat-shrinkable tube may be 5% or more, preferably about 5 to 30%, more preferably about 8 to 30%, and still more preferably about 10 to 30%. Can be mentioned. When the thermal contraction rate X is in such a range, a thermal contraction rate sufficient to cover the surface of the member can be exhibited in a low temperature environment. The heat shrinkage rate Y% of the heat shrinkable tube may satisfy the above relationship with the heat shrinkage rate X%, preferably about 5 to 33%, more preferably about 9 to 30%, Preferably, it is about 11 to 30%.

The ratio (Y / X) of the heat shrinkage rate X% at a low temperature of 150 ° C. and the heat shrinkage rate Y% at a high temperature of 300 ° C. is within the range of 0.9 to 1.1. Although it may be sufficient, a range of 0.95 to 1.1 is more preferable.

In addition, the heat-shrinkable tube of the present invention exhibits a heat shrinkage rate sufficient to cover the surface of a member in a low-temperature environment, and from the viewpoint of suppressing variation in thickness, from an environment at a temperature of 25 ° C. The degree of crystallinity A after being placed in a gas phase at a temperature of 150 ° C. for 5 minutes is preferably 10% or less, more preferably 8% or less, and even more preferably 5% or less. In addition, the lower limit of the crystallinity A is, for example, 0%.

The heat-shrinkable tube of the present invention has a crystallinity B after being placed in a gas phase at a temperature of 200 ° C. for 5 minutes from an environment at a temperature of 25 ° C. from the viewpoint of exhibiting high mechanical strength after heat shrinkage. Is preferably 20% or more, more preferably 25% or more, and further preferably 30% or more. In addition, the upper limit of the crystallinity degree B is, for example, 35%.

The crystallinity A of the heat-shrinkable tube of the present invention is measured as follows. The heat-shrinkable tube is transferred from an environment at a temperature of 25 ° C. to a constant temperature bath at a temperature of 150 ° C. in an atmospheric environment, heated for 5 minutes, and the crystallinity A is measured by the following method. Separately, each heat-shrinkable tube is transferred from an environment at a temperature of 25 ° C. to a constant temperature bath at a temperature of 200 ° C. in an atmospheric environment, heated for 5 minutes, and the crystallinity B is measured by the following method.

<Measurement method of crystallinity>
In accordance with the measurement method described in JIS K 7121 using a differential scanning calorimeter (for example, DSC-60 manufactured by Shimadzu Corporation), the amount of crystallization when the temperature is increased from 30 ° C. to 380 ° C. at 10 ° C./min. The heat of fusion is measured and calculated by the following formula.
Crystallinity = (heat of fusion−heat of crystallization) / 100% heat of fusion at the time of crystallization × 100

2. Manufacturing method of heat-shrinkable tube The heat-shrinkable tube of the present invention having the above-mentioned heat-shrinking characteristics can be preferably manufactured by a manufacturing method including, for example, the following forming process and stretching process.

(Molding process)
The following general formula (A):
— (Ar ¹ —C (═O) —Ar ² —O—Ar ³ —O) — (A)
[In the general formula (1), the group Ar ¹ , the group Ar ² , and the group Ar ³ are each independently an aromatic hydrocarbon group that may have a substituent. ]
A molded tube formed by heating a thermoplastic resin containing a polymer having a repeating unit represented by the following formula is heated to a temperature of 340 ° C. or more and subjected to continuous melt extrusion to a temperature of 130 to 160 ° C. (first After that, the tube is further cooled to a temperature of 10 to 50 ° C. (second cooling step) to obtain an unstretched tube.

In the molding step, the composition of the thermoplastic resin that is subjected to continuous melt extrusion molding is as described above in the section “1. Heat-shrinkable tube”. Specifically, in the molding step, first, a thermoplastic resin having the above composition, and raw materials such as fillers and additives added as necessary are heated to a temperature of 340 ° C. or higher and mixed, followed by continuous melt extrusion. A molded tube formed into a tube shape by molding is obtained.

As a method for mixing raw materials, known mixing means can be applied, for example, biaxial extrusion molding can be used. For continuous melt extrusion, known melt extrusion means can be applied, and examples thereof include a method using a single screw extruder and a circular mandrel die for extrusion. At this time, the thickness of the obtained molded tube can be adjusted to a desired thickness by appropriately setting the lip width and extrusion molding conditions of the circular mandrel. In order to accurately maintain the shape of the tube after discharge, a mandrel such as an air ring may be used at the die outlet. In addition, by installing a circular mandrel die at the tip of the twin screw extruder, mixing of raw materials and melt extrusion can be performed at once to form a tube.

The heating temperature in continuous melt extrusion is a heat shrinkage rate sufficient to cover the surface of the member in a low temperature environment (for example, about 150 ° C.) (for example, the heat shrinkage rate is 5%). From the viewpoint of exhibiting the above), the temperature may be 340 ° C. or higher, and may be appropriately set according to the composition of the thermoplastic resin used as a raw material. From the viewpoint of suppressing variation in thickness while imparting Y (%), and from the viewpoint of improving characteristics such as heat resistance of a coating member obtained by thermally shrinking the obtained heat-shrinkable tube, preferably 350 to 420 ° C. About 370 to 400 ° C. is preferable.

In the molding process, after forming the molded tube, it is cooled to a temperature of 130 to 160 ° C. (first cooling process), further cooled to a temperature of 10 to 50 ° C. (second cooling process), and unstretched Get the tube. As a result, even though the thickness of the resulting heat-shrinkable tube is as thick as 600 μm or more, the variation in thickness is suppressed, and a sufficient heat shrinkage rate is provided to cover the surface of the member in a low-temperature environment. It will be possible to demonstrate.

In the first cooling step, the temperature of the molded tube at the start of cooling of the molded tube is preferably about 280 to 400 ° C. The temperature of the molded tube after the first cooling step is not particularly limited as long as it is 130 to 160 ° C., but is preferably about 130 to 150 ° C.

In the first cooling step, the cooling time for cooling the molded tube is preferably 30 seconds or less, more preferably 20 seconds or less, and further preferably 1 to 15 seconds.

In the second cooling step, which is performed subsequent to the first cooling step, the temperature of the molded tube at the start of cooling of the molded tube is about the above-mentioned temperature immediately after the first cooling step (ie, 130 to 160 ° C. Degree, preferably about 130 to 150 ° C.). The temperature of the molded tube after the second cooling step is not particularly limited as long as it is 10 to 50 ° C., but is preferably about 10 to 40 ° C.

In the second cooling step, the cooling time for cooling the molded tube is preferably 5 seconds or more, more preferably 10 seconds or more, and further preferably 10 to 90 seconds.

The cooling of the formed tube in the first cooling step and the second cooling step can be performed using, for example, a cooling mandrel. More specifically, the melt-extruded thermoplastic resin in a molten state is formed into a tube shape along a mandrel-shaped sizing (sizing mandrel). At this time, the temperature on the mold lip side of the sizing mandrel is set to 130 to 160 ° C. (preferably 130 to 150 ° C.) (first cooling step), and the portion beyond that is set to 10 to 50 ° C. (preferably 10 to 10 ° C.). 40 ° C.) (second cooling step), the first cooling step and the second cooling step of the molded tube can be performed.

(Stretching process)
In the stretching process, the tube (unstretched tube) molded in the molding process is stretched. By this stretching step, the heat shrinkability is imparted to the heat shrinkable tube. This stretching process may be performed continuously with the molding process or may be performed in a separate process. The tube stretching step can be performed by tubular stretching using a known stretching apparatus. The tubular stretching may be simultaneous biaxial stretching or uniaxial stretching only in the TD direction.

In the stretching step, stretching conditions are set in order to give the predetermined heat shrinkage rate to the heat-shrinkable tube of the present invention. Specifically, the thermal shrinkage rate in the TD direction is controlled by the ratio of the outer diameter of the unstretched tube to the outer diameter of the stretched tube (lateral stretching ratio). In order to obtain a heat-shrinkable tube having the above-described heat shrinkage rate, the transverse direction draw ratio is set to 1.10 or more. Further, the shrinkage rate in the MD direction is controlled by the ratio of the speed of the unstretched tube introduced into the stretched portion and the speed of the stretched tube detaching from the stretched portion (longitudinal stretch ratio). On the other hand, in order to obtain a heat-shrinkable tube having the above-described heat shrinkage rate, the longitudinal stretching ratio may be arbitrary. For this reason, only the stretching in the transverse direction may be performed in a somewhat free state without fixing the length in the longitudinal direction. Depending on the intended use, the stretching ratio in the machine direction may be set in the range of about 0.95 to 1.20 times.

The temperature under the atmosphere in which the stretching step is performed is preferably set within the range from the temperature at which the elastic modulus of the thermoplastic resin used as a raw material is rapidly reduced to the crystallization temperature of the resin. Since the polymer having the repeating unit represented by the general formula (1) is a crystalline resin, crystallization progresses as the stretching temperature increases. As the crystallization progresses, the mechanical strength of the tube can be increased, but the thermal contraction rate of the tube becomes smaller. Therefore, in order to achieve both the viewpoint of suppressing variation in thickness while imparting the predetermined heat shrinkage ratio to the covering member and the viewpoint of increasing the heat resistance and mechanical strength after covering the member, stretching is performed. The temperature under the atmosphere in which the process is performed is preferably about 120 to 160 ° C., more preferably about 130 to 150 ° C. By selecting a temperature below the crystallization temperature of the thermoplastic resin so that the crystallization does not progress so much, it is possible to exhibit a sufficient thermal contraction rate to cover the surface of the member in a low temperature environment. it can.

The heat-shrinkable tube of the present invention is obtained as a long tube through the molding process and the stretching process. Therefore, the heat-shrinkable tube of the present invention can be cut into a desired length according to the size of the member to be heat-shrinked and coated to obtain the heat-shrinkable tube of the present invention.

3. Manufacturing method of heat-resistant member The heat-resistant member of the present invention is obtained by coating the surface of a member with a coating member obtained by thermally shrinking the heat-shrinkable tube of the present invention. The heat-resistant member of the present invention can be manufactured by disposing a member inside the heat-shrinkable tube of the present invention and thermally shrinking the heat-shrinkable tube, thereby covering the member with the heat-shrinkable tube. it can. More specifically, the heat-resistant member of the present invention can be suitably produced by a method comprising the following steps.

The step of disposing the member inside the heat-shrinkable tube of the present invention The heat-shrinkable tube of the present invention is heated to a temperature of 160 ° C. or lower and thermally contracted, whereby the member is heat-shrinkable (the heat-shrinkable tube of the present invention Shrinking process for covering with a heat-shrinkable coating member)

In the step of disposing a member inside the heat-shrinkable tube of the present invention, details of the heat-shrinkable tube of the present invention are as described above. In addition, the member is not particularly limited, but from the viewpoint of imparting heat resistance and the like by suitably covering the outer surface with the heat-shrinkable covering member of the heat-shrinkable tube of the present invention, a cylindrical or cylindrical member It is preferable that The member is used in a field where excellent heat resistance and wear resistance are required, and specific examples include CFRP rollers.

(Shrinking process)
In the shrinking step, with the member disposed in the heat-shrinkable tube of the present invention, the heat-shrinkable tube is heated to a temperature of 160 ° C. or less, and the heat-shrinkable tube is thermally shrunk to heat the surface of the member. Close the shrinkable tube. That is, in this shrinking step, the heat-shrinkable tube of the present invention is coated with the covering member that is heat-shrinked to obtain a heat-resistant member. As described above, the heat-shrinkable tube of the present invention exhibits a sufficient heat shrinkage rate (for example, a heat shrinkage rate of 5% or more) to cover the surface of the member in a low temperature environment (for example, about 150 ° C.). Even at 150 ° C. or lower, it can be thermally shrunk, and a heat-resistant member is suitably obtained.

Schematic diagram for explaining the shrinking process is shown in FIG. In the shrinking step, as shown in FIG. 2, the member 2 is disposed in the heat-shrinkable tube 1, and in this state, the heat-shrinkable tube 1 is heated and shrunk inward, so that the heat-shrinkable tube 1 is moved to the member 2. The heat-shrinkable tube 1 is heat-shrinked to cover the surface of the member 2 to obtain a heat-resistant member.

The heating temperature in the shrinking step can be appropriately set according to the heat resistant temperature of the member, but in the method for producing a heat resistant member of the present invention, the shrinking step can be suitably performed at a low temperature of 160 ° C. or lower. From the viewpoint of suitably heat-shrinking the heat-shrinkable tube of the present invention and bringing it into close contact with the surface of the member, the heating temperature in the shrinking step is preferably about 150 to 160 ° C., preferably about 152 to 155 ° C. . The heating time is appropriately set according to the size of the heat-shrinkable tube and the member. For example, the heating time is 10 minutes or more after the heat-shrinkable tube reaches the above temperature, preferably about 10 to 15 minutes. During this time, the above temperature may be maintained.

For covering the member with the heat-shrinkable tube of the present invention, for example, in the case of a columnar or cylindrical member, the surface of the member is covered with the heat-shrinkable tube of the present invention and allowed to stand in a free state on a concentric shaft. It can be performed by heating in a thermostat.

(Annealing process)
In the manufacturing method of the heat resistant member of this invention, you may have an annealing process further after a shrinkage | contraction process. In the annealing process, the heat resistant member is heated at a temperature higher than the heating temperature in the shrinking process. The annealing process is performed as necessary in order to increase the mechanical strength of the heat-resistant member (particularly to increase the tensile modulus and wear resistance). That is, the annealing process increases the mechanical strength of the covering member made of the thermoplastic resin containing the polymer.

In the present invention, the heating temperature of the heat resistant member in the annealing step is preferably higher than the heating temperature in the shrinking step and higher than the crystallization temperature of the thermoplastic resin constituting the covering member, Specifically, the temperature is preferably about 160 to 200 ° C, more preferably about 170 to 180 ° C.

The annealing step may be performed by continuously increasing the heating temperature after heating in the above-described shrinking step, or may be performed after cooling the coating member after the shrinking step. The heating time is appropriately set according to the size of the heat resistant member. For example, the heating time is 30 minutes or more after the surface temperature of the heat resistant member reaches the above temperature, preferably about 60 to 90 minutes. What is necessary is just to hold | maintain said temperature.

The annealing step can be performed, for example, by heating the heat resistant member in a constant temperature layer.

4). Manufacturing method of covering member The covering member of this invention heat-shrinks the heat-shrinkable tube of this invention. The covering member of this invention can be suitably manufactured by the method provided with the following processes.

Step of preparing the heat-shrinkable tube of the present invention The heat-shrinkable tube of the present invention is heated to a temperature of 160 ° C. or lower to cause heat shrinkage.

That is, if the heat-shrinkable tube of the present invention is heated to a temperature of 160 ° C. or lower and thermally contracted, the coated member of the present invention can be obtained. The heat resistant member is obtained.

In the step of preparing the heat-shrinkable tube of the present invention, details of the heat-shrinkable tube of the present invention are as described above. Moreover, in the manufacturing method of the coating | coated member of this invention, about a shrinking process, it is the same as that of "3. Manufacturing method of a heat resistant member", and may further have the above-mentioned annealing process as needed.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples. In the present invention, the heat shrinkage rate, crystallinity, and thickness variation of the heat shrinkable tube were measured as follows.

<Heat shrinkage>
Each heat-shrinkable tube obtained in Examples, Comparative Examples, and Reference Examples was transferred from an environment at a temperature of 25 ° C. to an oven at a temperature of 150 ° C. in an atmospheric environment, heated for 5 minutes, and heat shrinkage rate. X% was measured. Separately, each heat-shrinkable tube was transferred from an environment at a temperature of 25 ° C. to a thermostatic bath at a temperature of 300 ° C. in an atmospheric environment, heated for 5 minutes, and the heat shrinkage rate Y% was measured. The heat shrinkage ratios X and Y (%) are calculated by the following calculation formulas for the heat shrinkable tubes before and after heat shrinkage, by cutting the tube in the longitudinal direction, opening the tube, and measuring the circumference of the tube with calipers. Determined by The results are shown in Table 1.
Heat shrinkage rate = (perimeter before heat shrink-circumference after heat shrink) / circumference before heat shrink x 100 (%)

<Crystallinity>
Each heat-shrinkable tube obtained in Examples, Comparative Examples, and Reference Examples was transferred from an environment at a temperature of 25 ° C. to a constant temperature bath at a temperature of 150 ° C. in an atmospheric environment and heated for 5 minutes. Was used to measure the crystallinity A. Separately, each heat-shrinkable tube was transferred from an environment at a temperature of 25 ° C. to a temperature-controlled bath at a temperature of 200 ° C., heated for 5 minutes, and the crystallinity B was measured by the following method. The results are shown in Table 1.

<Measurement of thickness variation>
Each heat-shrinkable tube obtained in Examples, Comparative Examples, and Reference Examples was cut to 50 mm in the longitudinal direction. Next, with respect to each longitudinal direction (eight locations at equal intervals in the circumferential direction), the thickness was measured at 10 locations at intervals of 5 mm, and the variation in thickness was calculated by the following formula. Among the 8 thickness variations in the circumferential direction, the one with the largest variation value was defined as the thickness variation (%) of the heat-shrinkable tube.
Variation in thickness (%) = (maximum thickness-minimum thickness) / average thickness x 100

<Example 1>
A heat-shrinkable tube was produced by the following molding process and stretching process.
(1) Molding process of a thermoplastic resin into a tube shape As a thermoplastic resin, PEEK (polyetheretherketone, PEEK650G manufactured by Victrex) is charged into a single screw extruder having a screw diameter of 40 m and heated to 380 ° C. did. Next, it is melt extruded from a lip diameter φ146 mm die at a speed of 0.3 m / min to form a molded tube, and sizing mandrels (external diameter φ110 mm, 130 mm long lip side (extrusion discharge side)) are filled with pressurized water inside the mandrel. Circulate and set to 140 ° C. (perform the first cooling step) and use the remaining 100 mm length to circulate water to set to 30 ° C. (perform the second cooling step)) A cooling step (140 ° C. for 6 seconds) and a second cooling step (30 ° C. for 20 seconds) were performed to obtain an unstretched tube having an inner diameter of 110 mm and a wall thickness of 800 μm.
(2) Stretching process of unstretched tube The unstretched tube obtained in the molding process was cut to a length of 4000 mm and expanded with a mandrel having an outer diameter of φ150 mm heated to 150 ° C., and the Tg was maintained while maintaining the inner diameter of the tube. By cooling to a temperature below (143 ° C.) (80 ° C.), a shrinkable tube having an inner diameter of 150 mm and a wall thickness of 610 μm was obtained.

<Example 2>
A heat-shrinkable tube was produced by the following molding process and stretching process.
(1) Molding process of a thermoplastic resin into a tube shape As a thermoplastic resin, PEEK (polyetheretherketone, PEEK650G manufactured by Victrex) is charged into a single screw extruder having a screw diameter of 40 m and heated to 380 ° C. did. Next, it is melt extruded from a lip diameter φ146 mm die at a speed of 0.3 m / min to form a molded tube, and sizing mandrels (external diameter φ110 mm, 130 mm long lip side (extrusion discharge side)) are filled with pressurized water inside the mandrel. Circulate and set to 140 ° C. (perform the first cooling step), and set the remaining 100 mm length to 30 ° C. by circulating water (perform the second cooling step) A cooling step (140 ° C. for 6 seconds) and a second cooling step (30 ° C. for 20 seconds) were performed to obtain an unstretched tube having an inner diameter of 110 mm and a wall thickness of 1200 μm.
(2) Stretching process of unstretched tube The unstretched tube obtained in the molding process was cut to a length of 4000 mm and expanded with a mandrel having an outer diameter of φ150 mm heated to 150 ° C., and the Tg was maintained while maintaining the inner diameter of the tube. By cooling to a temperature of (143 ° C.) or lower (80 ° C.), a shrinkable tube having an inner diameter of 150 mm and a wall thickness of 990 μm was obtained.

<Comparative Example 1>
A tube was manufactured by the following molding process and stretching process.
(1) Molding process of a thermoplastic resin into a tube shape As a thermoplastic resin, PEEK (polyetheretherketone, PEEK650G manufactured by Victrex) is charged into a single screw extruder having a screw diameter of 40 m and heated to 380 ° C. did. Next, it is melt extruded from a lip diameter φ146 mm die at a speed of 0.3 m / min to form a molded tube, and sizing mandrels (external diameter φ110 mm, 130 mm long lip side (extrusion discharge side)) are filled with pressurized water inside the mandrel. Circulating and setting to 140 ° C. (the cooling process is performed), and the remaining 100 mm length is 140 ° C., the cooling process (at 140 ° C. for 26 seconds) is performed, and an unstretched tube having an inner diameter of φ110 mm and a wall thickness of 800 μm is obtained. Obtained.
(2) Unstretched tube stretching step The unstretched tube obtained in the molding step (naturally cooled to room temperature) was cut to a length of 4000 mm and expanded with an outer diameter φ150 mm mandrel heated to 150 ° C. Attempts were made to prevent the unstretched tube from being uniformly expanded, so that the unstretched tube could not be hung on the mandrel and could not be stretched, so a shrinkable tube could not be obtained.

<Comparative example 2>
A heat-shrinkable tube was produced by the following molding process and stretching process.
(1) Molding process of a thermoplastic resin into a tube shape As a thermoplastic resin, PEEK (polyetheretherketone, PEEK650G manufactured by Victrex) is charged into a single screw extruder having a screw diameter of 40 m and heated to 380 ° C. did. Next, it is melt extruded from a lip diameter φ146 mm die at a speed of 0.3 m / min to form a molded tube, and sizing mandrels (external diameter φ110 mm, 130 mm long lip side (extrusion discharge side)) are filled with pressurized water inside the mandrel. Circulate and set to 30 ° C (perform the cooling process) and perform the cooling process (30 ° C for 26 seconds) using the remaining 100mm length (30 ° C) to obtain an unstretched tube with an inner diameter of φ110mm and a wall thickness of 800μm. Obtained. However, at this time, an appearance defect of a ring-shaped pattern occurred on the outer periphery of the molded tube.
(2) Stretching process of unstretched tube The unstretched tube obtained in the molding process was cut to a length of 4000 mm and expanded with a mandrel having an outer diameter of φ150 mm heated to 150 ° C., and the Tg was maintained while maintaining the inner diameter of the tube. By cooling to a temperature below (143 ° C.) (80 ° C.), a shrinkable tube having an inner diameter of 150 mm and a wall thickness of 610 μm was obtained. However, the ring-shaped pattern of the molded tube formed in the molding process was more prominently formed on the outer periphery of the shrinkable tube by this stretching process.

<Comparative Example 3>
A heat-shrinkable tube was produced by the following molding process and stretching process.
(1) Molding process of a thermoplastic resin into a tube shape As a thermoplastic resin, PEEK (polyetheretherketone, PEEK650G manufactured by Victrex) is charged into a single screw extruder having a screw diameter of 40 m and heated to 380 ° C. did. Next, melt extrusion at a speed of 0.3 m / min from a lip diameter φ80 mm die, and without forming a cooling step at a predetermined temperature, a sizing inner diameter φ150 mm, an inner diameter 150 φmm, and a wall thickness of 650 μm, This was a heat-shrinkable tube.

<Reference Example 1>
A heat-shrinkable tube was produced by the following molding process and stretching process.
(1) Molding process of a thermoplastic resin into a tube shape As a thermoplastic resin, PEEK (polyetheretherketone, PEEK650G manufactured by Victrex) is charged into a single screw extruder having a screw diameter of 40 m and heated to 380 ° C. did. Next, it is melt extruded from a lip diameter φ146 mm die at a speed of 0.3 m / min to form a molded tube, and sizing mandrels (external diameter φ110 mm, 130 mm long lip side (extrusion discharge side)) are filled with pressurized water inside the mandrel. Circulate and set to 140 ° C. (the cooling process is performed), the remaining 100 mm length is 140 ° C., and the cooling process (at 140 ° C. for 26 seconds) is performed to obtain an unstretched tube having an inner diameter of φ110 mm and a wall thickness of 200 μm. Obtained.
(2) Stretching process of unstretched tube The unstretched tube obtained in the molding process was cut to a length of 4000 mm and expanded with a mandrel having an outer diameter of φ150 mm heated to 150 ° C., and the Tg was maintained while maintaining the inner diameter of the tube. By cooling to a temperature below (143 ° C.) (80 ° C.), a shrinkable tube having an inner diameter of 150 mm and a wall thickness of 150 μm was obtained.

[Evaluation of tensile modulus and wear resistance]
(Sample 1)
Sample 1 was prepared by heating the shrinkable tube obtained in Example 1 for 30 minutes in a thermostatic bath at 150 ° C. in an atmospheric environment.

(Sample 2)
Sample 2 was obtained by heating the shrinkable tube obtained in Example 1 for 30 minutes in a thermostatic chamber at 150 ° C. in an atmospheric environment and further annealing (heating in a thermostatic chamber in an atmospheric environment at 170 ° C. for 1 hour). It was.

(Measurement method of tensile modulus)
The tensile elastic modulus in the circumferential direction of the tubes of

Samples

1 and 2 was measured with a test piece based on JIS K 7127 under a normal temperature environment and a tensile speed of 10 mm / min. As a result, the tensile modulus of sample 1 was 2.0 GPa, and the tensile modulus of sample 2 was 2.8 GPa.

(Evaluation of wear resistance)
In accordance with JIS K 7218, the pin-on-disk method was used for evaluation. The evaluation conditions were unlubricated, pressure was applied at 2.76 MPa under a room temperature condition, and the counterpart material was set to S45C (Ra 1.1) at a peripheral speed of 0.15 m / s. And the test piece weight before evaluation and the test piece weight after 240 minutes were measured, and it converted into wear volume and evaluated. As a result, the wear volume of sample 1 was 1.6 mm ² , and the wear volume of sample 2 was 1.1 mm ² .

DESCRIPTION OF SYMBOLS 1 ... Heat-shrinkable tube 2 ... Member 10 ... Covering member L ... Tube length M ... Tube thickness N ... Tube outer diameter

Claims

The following general formula (A):
— (Ar 1 —C (═O) —Ar 2 —O—Ar 3 —O) — (A)
[In General Formula (A), the group Ar 1 , the group Ar 2 , and the group Ar 3 are each independently an aromatic hydrocarbon group that may have a substituent. ]
A heat-shrinkable tube formed of a thermoplastic resin containing a polymer having a repeating unit represented by:
The wall thickness is 600 μm or more,
Variation in the longitudinal direction of the wall thickness is 10% or less,
When the heat shrinkage rate when heated for 5 minutes in the gas phase at 150 ° C. is X% and the heat shrinkage rate when heated for 5 minutes in the gas phase at 300 ° C. is Y%, A heat-shrinkable tube that satisfies this relationship.
5 ≦ X
0.9 ≦ Y / X ≦ 1.1
The heat-shrinkable tube according to claim 1, wherein the degree of crystallinity after being placed in a gas phase at a temperature of 150 ° C for 5 minutes from an environment at a temperature of 25 ° C is 10% or less.
The heat-shrinkable tube according to claim 1 or 2, wherein the degree of crystallinity after being placed in a gas phase at a temperature of 200 ° C for 5 minutes from an environment at a temperature of 25 ° C is 20% or more.
The heat-shrinkable tube according to any one of claims 1 to 3, wherein the heat-shrinkable tube is a cylindrical endless tube.
The following general formula (A):
— (Ar 1 —C (═O) —Ar 2 —O—Ar 3 —O) — (A)
[In the general formula (1), the group Ar 1 , the group Ar 2 , and the group Ar 3 are each independently an aromatic hydrocarbon group that may have a substituent. ]
A thermoplastic resin containing a polymer having a repeating unit represented by the following is heated to a temperature of 340 ° C. or higher, and a molded tube formed into a tube shape by continuous melt extrusion molding is cooled to a temperature of 130 to 160 ° C. Further, a molding step of cooling to a temperature of 10 to 50 ° C. to obtain an unstretched tube,
Stretching the unstretched tube molded in the molding step to obtain a heat-shrinkable tube,
A method for producing a heat-shrinkable tube.
The method for producing a heat-shrinkable tube according to claim 5, wherein the wall thickness is 600 μm or more.
Preparing a heat-shrinkable tube according to any one of claims 1 to 4,
Placing a member inside the heat shrinkable tube;
A shrinking step of coating the member with a heat shrinkable tube by heating the heat shrinkable tube to a temperature of 160 ° C. or less and causing heat shrinkage;
A method for producing a heat-resistant member.
Preparing a heat-shrinkable tube according to any one of claims 1 to 4,
A shrinking step in which the heat-shrinkable tube is heated to a temperature of 160 ° C. or less and thermally contracted;
A method for manufacturing a covering member.