JPH04364925A - Heat-resistant, heat-shrinkable tube and its manufacturing method - Google Patents

Abstract

PURPOSE:To manufacture a tube of superior heat shrinkability in the diameter direction by heat shrinking a tubular body composed of a thermoplastic elastomer composition containing a specified copolymer at the specified degree of crosslinking in the direction square to the length direction. CONSTITUTION:A thermoplastic elastomer composition containing 30-70wt.% of an ethylene-propylene-dien copolymer and 70-30wt.% of an ethylene vinyl acetate copolymer (5-30wt.% vinyl acetate content) is extruded out of a tube extruder, and electron radiation is emitted by an electron radiation emitting device to prepare an electron radiation emission strong tubeshaped body. The tube-shaped body is stretched (expanded) in the direction perpendicular to the lengitudinal direction to manufacture a heat-shrinkable tube 10. In that case, crosslinking caused by irradiation of an electron beam is preferably formed in a manner that gel percentage is 70-95%, particularly 80-90wt.%. The tube 10 is thermally shrunk and loaded to make it adhere to a required place of a body 11 to be installed.

Description

Detailed Description of the Invention [0001] [Industrial Application Field] The present invention relates to thermoplastic elastomer
Regarding the tube and its manufacturing method, it exhibits excellent heat shrinkability in the diametrical direction, especially in the low temperature range, has heat resistance and chemical resistance, is slip-proof and highly flexible, and has particularly good heat resistance. A heat-resistant heat-shrinkable tube that can be used as an easily removable covering material in the field of various rollers such as paper feed rolls in office machines, copying machines, etc. that require Regarding the manufacturing method. [0002] Conventionally, in the field of various rollers such as office machines and copying machines that require heat resistance, natural rubber, synthetic rubber (chloroprene), urethane materials, and foams of these materials have been hollowed out. Then, fix it to the core metal with adhesive, and then apply it with a roller.
There is a method in which the roll surface is then polished and finished. However, these rollers have poor heat resistance and
At temperatures above 0° C., there are problems such as dimensional changes. In addition, since it is fixed to the core metal with adhesive, there are also problems such as the inability to use it as a replacement covering material. For example, when a shrinkable tube is attached to the handle of a fishing rod, golf club, baby carriage, tool, etc. as a grip member, it is important that the tube exhibits excellent heat shrinkability in the diametrical direction. Then, the tube becomes
It can function as a shrink tube,
Further, it is also possible to prevent it from being easily detached from the body to be attached. In this case, it is important that the heat shrinkability is good in a low temperature region, that is, the heat shrinkage rate is excellent in a low temperature atmosphere. On the other hand, the ability of the tube to function as a shrinkable tube and the ease with which it can be removed from the object to which it is attached is related to the tube's slip performance, that is, its anti-slip properties, and it is necessary to have excellent anti-slip properties. It is. Furthermore, if the grip member is too hard, various problems tend to occur, so it is necessary to maintain flexibility. These anti-slip properties and flexibility are easily affected by the ambient temperature, and the anti-slip properties and flexibility vary greatly depending on the ambient temperature. Moreover, the anti-slip properties and flexibility decrease significantly depending on the ambient temperature, especially in winter and in cold regions. It may become unusable due to deterioration of its elasticity or flexibility. Furthermore, although the adhesion of the tube to the object to which it is attached is contradictory, it is difficult to attach or remove the tube when removing it from the object by using a cutter for replacement or the like. It is necessary to be excellent at Conventionally, shrink tubes made of soft vinyl chloride resin have been used to cover clothesline poles, etc., but their anti-slip properties and flexibility deteriorate significantly depending on the ambient temperature, especially in winter and in cold regions. It is often unusable due to deterioration. On the other hand, although it is different from a shrink tube, it can be used to coat objects such as natural rubber, synthetic rubber, and soft vinyl chloride resin.
However, since it cannot be easily installed and removed at home, it is difficult to replace. SUMMARY OF THE INVENTION It is an object of the present invention to provide a technology that can eliminate the drawbacks of the prior art, and also to provide a material that exhibits excellent heat shrinkability in the diametrical direction. It also has excellent heat shrinkage in low-temperature atmospheres, excellent slip resistance and flexibility, and can be removed from the attached object using a cutter for replacement etc. The purpose is to provide a device with excellent workability for attaching and detaching. Another object of the present invention is to further improve the heat resistance and chemical resistance of such tubes that have excellent heat shrinkability, anti-slip properties, flexibility, and workability for attachment and detachment. Further objects and novel features of the present invention will become apparent from the following description and accompanying drawings. [Means and effects for solving the problems] The present invention provides an ethylene-propylene-diene copolymer containing 30 to 70% by weight.
and 70 to 30% by weight of an ethylene-vinyl acetate copolymer (vinyl acetate content: 5 to 30% by weight), and the gel fraction indicating the degree of crosslinking is 70 to 95% by weight. % of a tube-like body that is heated and stretched in the diametrical direction relative to the length direction, and 30 to 70% by weight of an ethylene-propylene-diene copolymer; Ethylene-vinyl acetate copolymer (vinyl acetate content 5-30% by weight) 70-30% by weight
A tube-shaped body made of a thermoplastic elastomer composition containing
The tube is cross-linked and gas is blown into the tube.
The present invention relates to a method for producing a heat-shrinkable tube, which is characterized in that the tubular body is heated and stretched in the diameter direction with respect to the length direction at a stretching ratio of 1.2 to 2.0 times. The tube according to the present invention exhibits excellent heat shrinkability in the diametrical direction by heating and stretching in the diametrical direction as described above, and can exhibit excellent functions as a shrinkable tube. Furthermore, since it exhibits excellent heat shrinkability in the diametrical direction, it can be prevented from being easily separated from the object to be attached, even without using an adhesive. Further, the heat shrinkability in the diametrical direction is good in a low temperature region, that is, the heat shrinkage rate in a low temperature atmosphere is excellent. Incidentally, in the case of polyvinyl chloride, generally
The heat shrinkage start temperature is around 120°C, and polyethylene and polypropylene also show a similar heat shrinkage start temperature.
Even for polyvinylidene chloride, which is said to have a low heat shrinkage start temperature, the heat shrinkage rate in a low temperature atmosphere of 50 to 60°C is small. After the tube according to the present invention is left in a refrigerator at 0°C for 24 hours,
I tried to pull it out with my bare hands, but I couldn't pull it out at all.It has excellent anti-slip properties, has a higher coefficient of friction than soft vinyl chloride resin, and is difficult to slip, so it can be used in low-temperature areas, especially in winter and cold regions. Can maintain slip resistance and flexibility. In addition, it has excellent workability in attaching and detaching when removing it from the object to be attached using a cutter etc. for replacement etc.
This is thought to be because there is no plasticizer bleed unlike in soft vinyl chloride resins. Then, the present inventors found that 30 to 70% by weight of ethylene-propylene-diene copolymer
and 70 to 30% by weight of ethylene-vinyl acetate copolymer (vinyl acetate content: 5 to 30% by weight).
It has been found that heat resistance and chemical resistance can be improved by crosslinking the material by irradiating it with an electron beam or the like before stretching it in the diametrical direction of the tube. That is, such a crosslinked elastomer tube has almost no dimensional change in hot water or in an oven, and can be improved in hot water resistance and heat resistance. Further, such a crosslinked elastomer tube exhibits stability when immersed in chemicals, and can also be improved in chemical resistance. Next, a tube and a method for manufacturing the same according to the present invention will be explained with reference to the drawings as appropriate. FIG. 2 shows an example of forming a tube according to the invention prior to diametrically heated stretching. A thermoplastic elastomer composition containing 30 to 70% by weight of an ethylene-propylene-diene copolymer and 70 to 30% by weight of an ethylene-vinyl acetate copolymer (vinyl acetate content of 5 to 30% by weight), Chew
It is extruded while blowing air from a tube extruder 1, cooled in a water tank 2, taken up by a take-up roll 3, and irradiated with an electron beam by an electron beam irradiation device E to produce an electron beam irradiation crosslinked tube-like product. Get 4. Next, as shown in FIG. 3, it passes through the hot water tank 5,
After the tube-shaped body 4 is sealed with the feeding-side nip roll 6, air is again blown into the tube-shaped body 4.
The tube-shaped body 4 is stretched (inflated) in the diametrical direction with respect to the length direction, and the take-up nip roll 7 is closed to seal the internal air.At the same time, the take-up roll 8 is driven to The body 4 is once cooled through a cooling bath 9 and wound up to obtain a heat-shrinkable tube 10. In this case, crosslinking by electron beam irradiation is such that the gel fraction (indicated by the weight of the final soluble content after immersion in boiling p-xylene for 15 hours) is 70 to 95% by weight, particularly 80 to 90% by weight. It is preferable to make it so that When the gel fraction is less than 70% by weight, problems occur in hot water resistance and heat resistance, and the tube is likely to be deformed. On the other hand, when the gel fraction exceeds 95% by weight, the tube tends to develop a bad odor. Also, move the tube in the inner diameter direction,
Re-blowing at a stretching ratio of 1.2 to 2.0 times as described below.
During the processing process, it becomes impossible to inflate (rupture). Cross-linking of elastomer tubes is performed using gamma radiation other than electron beams.
This may be carried out by irradiation with radiation or ultraviolet rays, or by chemical crosslinking using an organic peroxide or the like. Further, a crosslinking aid may be used. The stretching ratio of the tube-shaped body 4 in the diametrical direction relative to the longitudinal direction is suitably 1.2 to 2.0 times, although it depends on the wall thickness. If the stretching ratio is less than 1.2 times, it will not be able to exhibit its excellent function as a shrinkable tube, and if it exceeds 2.0 times, the tube will be damaged. The thickness of the tube-like body 4 is normally 0.05 to 2 mm. One form of the obtained tube and one mode of its use are shown in FIG. When the tube 10 is heat-shrinked and attached to the required part of the object 11 by hot air or hot air blowing, the tube 10 can be brought into close contact with the required part of the object 11. In the present invention, the ethylene-propylene-diene copolymer (EPDM) constituting the tube is
A copolymer containing ethylene, propylene, and a diene compound. Examples of the diene compound include ethylidene norbornene, 1,4-hexadiene, and dicyclopentadiene. The ethylene-propylene-diene copolymer (EPDM) has an ethylene content of 60 to 7.
Preferably, the content of propylene is 30 to 40 mol%, and the content of the diene compound is 1 to 10 mol%. A more preferable range is 62 to 66 ethylene.
mol %, propylene is 33-37 mol %, and diene compound is 3-6 mol %. The number average molecular weight of the ethylene-propylene-diene copolymer is preferably 400,000 to 600,000, and the density is 0.
87 g/cm3 or less is preferable. Furthermore, ethylene-
Melt index of propylene-diene copolymer (1
90℃, 2.16kg load) is 0.1 to 5.0
g/10 minutes is preferable, more preferably 0.3
It is 0 to 1.0 g/10 minutes. The ethylene-propylene-diene copolymer (EPDM) used in the present invention may contain α-olefins such as butene-1 or 4-methylpentene-1 within a range that does not impair the properties of the copolymer. May contain. The ethylene-vinyl acetate copolymer (EVA) used in the present invention is a copolymer containing 5 to 30% by weight of vinyl acetate. If the vinyl acetate content is less than 5% by weight, the rubber elasticity will be poor, while if it exceeds 30% by weight, it will be difficult to mold the tube. The preferred vinyl acetate content is 15 to 30% by weight. The melt index (190℃, 2.16kg load) is 0.2 to 2.
Preferably it is 5 g/10 minutes. Regarding the melt index, if it is less than 0.2 g/10 minutes, moldability will be poor, and if it exceeds 25 g/10 minutes, molding will be difficult. A preferred melt index is 15-25 g/10 minutes. The blending ratio of the ethylene-propylene-diene copolymer (EPDM) in the thermoplastic elastomer composition of the present invention is based on the resin component (100% by weight).
The content is preferably 30 to 70% by weight, particularly preferably 50 to 60% by weight. If the blending ratio of the ethylene-propylene-diene copolymer (EPDM) is lower than 30% by weight, the resulting tube will have a low stretching ratio and insufficient heat shrinkability. On the other hand, if it is higher than 70% by weight,
The moldability of the resulting tube is reduced. On the other hand, the blending ratio of the ethylene-vinyl acetate copolymer (EVA) is based on the resin component (10
0% by weight) is 70 to 30% by weight, especially 50 to 30% by weight.
It is preferably within the range of 40% by weight. The reason for limiting the blending ratio of the above ethylene-vinyl acetate copolymer (EVA) is exactly the opposite of the reason for limiting the above-mentioned ethylene-propylene-diene copolymer; if it is lower than 30% by weight, extrusion moldability decreases. , and if it is higher than 70% by weight, the tube
There is a large amount of sagging in the shape of a tube, resulting in poor moldability. The thermoplastic elastomer composition of the present invention comprises:
By adding polyolefin, its moldability etc. can be improved. The above polyolefins include ethylene, propylene, butene-1, pentene-1,
Homopolymers of α-olefins such as hexene-1, 4-methylpentene-1, ethylene and propylene or other α-
Examples include copolymers with olefins, copolymers of two or more of these α-olefins, and the like. Among these, low density polyethylene, linear low density polyethylene,
Polyethylenes such as medium density polyethylene and high density polyethylene are preferred. The above polyethylene has a density of 0.945
g/cm3 or less is preferable, and a melt index of 0.1 to 10 g/10 min is preferable. The amount of the above polyolefin added is the above-mentioned EPDM+EVA.
It is preferably 1 to 30 parts by weight, particularly preferably 5 to 20 parts by weight, based on the weight of (100 parts by weight). In addition, it is preferable to set the amount of polyolefin added so that the melt index of the composition to which polyolefin is added is 0.5 to 20 g/10 minutes. If the amount of polyolefin added is less than 1 part by weight, blocking resistance,
It is not effective in improving moldability, and if it exceeds 30 parts by weight, the elastomer properties of the resulting composition will decrease. The thermoplastic elastomer composition of the present invention can also have improved blocking resistance and heat resistance by adding a powdered inorganic filler. Inorganic fillers include talc, calcium carbonate, gypsum, carbon black, clay, kaolin, silica, diatomaceous earth, magnesium carbonate, barium carbonate, magnesium sulfate, barium sulfate, calcium sulfate, calcium phosphate, aluminum hydroxide, and oxide. Zinc, magnesium hydroxide, calcium oxide, magnesium oxide, titanium oxide, alumina, mica, shirasu balloon, zeolite, clay silicate, cement, silica fume, mica powder, etc. can be used, but talc, titanium oxide, calcium carbonate,
Silica and the like are particularly preferred. The average particle size of the inorganic filler is 5μ
m or less, preferably 1 to 3 μm. These powdered inorganic fillers can be used alone or in combination. The total amount of the powdered inorganic filler added is preferably 2 to 15 parts by weight, based on the weight of the EPDM+EVA (100 parts by weight). If the amount is less than 2 parts by weight, the effect of adding the powdered inorganic filler may not be noticeable, and if it exceeds 15 parts by weight, the strength of the resulting composition may actually decrease. However, since adding the above-mentioned inorganic filler reduces the stretching processability of the resulting composition, it is preferable to select the amount of the inorganic filler within the above-mentioned range depending on the use of the elastomer tube. . In the present invention, in addition to the above-mentioned additives, heat stabilizers, ultraviolet absorbers, antistatic agents, antioxidants, coloring agents, etc. can also be appropriately blended. EXAMPLES The present invention will be explained in more detail with reference to the following specific examples and comparative examples. Note that the test method in the following example is as follows. (1) Modulus (kg/cm2); ASTM D88
Compliant with 2. Measured in MD direction. (2) Heat shrinkage rate (%): The tube after being stretched in the transverse direction,
After immersing each tube in hot water (40 DEG C. to 100 DEG C.) for 10 seconds, the length and inner diameter of the tube were measured, and the heat shrinkage rate was determined from the following formula. Note that a negative (one) value indicates expansion. (3) Adhesion to the base material: Cover the base material with various tubes and observe the adhesion after heating at 70°C for 1 minute with a dryer or immersing in hot water at 80°C for 10 seconds. did. Good adhesion was rated O, slightly poor adhesion was rated Δ, and poor adhesion was rated X. (4) Friction coefficient: Based on ASTM D1894. A 1.5 mm thick sheet with the same composition and gel fraction as the tube.
Static friction coefficient (μs) and dynamic friction coefficient (μk) between copy paper and gloves (work gloves).
The shape after immersion for 2 hours was observed. (6) Heat resistance; various tubes (before lateral stretching)
The shape was observed after being left in a gear oven at .degree. C. for 24 hours. (7) Chemical resistance: Various tubes (before lateral stretching) are
) is expressed as the weight loss (% by weight) after 72-hour immersion at the boiling point of each solvent. In addition, chemical resistance at room temperature was observed, and those that were particularly excellent were rated ◎, those that were excellent were rated O, and those that were poor were rated X. Examples 1 to 5 and Comparative Examples 1 to 2. Ethylene-propylene-diene copolymer (Vistaron 3708
, manufactured by Exxon Chemical Co., Ltd.) and 40% by weight of ethylene-vinyl acetate copolymer (vinyl acetate content 28%, melt index 20 g/10 minutes) was melt-kneaded using an extruder. , a pellet was created. Using the prepared pellets, using a tube extruder, as shown in FIG.
A tube-shaped body of m was prepared, and this tube-shaped body was irradiated with an electron beam using an electron beam irradiation device (750 kv) manufactured by Nissin High Voltage. Next, as shown in Figure 3, 60
After passing the electron beam irradiation tube through a warm water bath at ℃ and sealing it with a nip roll on the feeding side, air is again blown into the inside of the tube. Stretch (inflate) in the diametrical direction (lateral direction) with respect to the length direction,
Close the nip roll on the take-off side to seal the internal air, and at the same time drive the take-off roll to temporarily remove the tube-shaped body.
It was cooled by passing it through a 25°C cooling bath and wound up to obtain an electron beam irradiation heat-shrinkable tube. Note that the rotational speed of the nip roll on the feeding side is 3.0 m/min. , and the rotational speed of the nip roll on the take-off side is 3.2 m/min. Met. As shown in Figure 1, the obtained electron beam irradiation tube was placed on a wooden cylinder, and then the coated tube was heated with a commercially available hair dryer to determine its adhesion to the wooden cylinder. was measured. Further, a similar coated tube was immersed in warm water, and its adhesion to a wooden cylinder was measured. The results are shown in Tables 1, 3 and 4. Table 1 shows that when the tube-shaped body was not re-blown in the lateral direction, the tube contracted by 11.5% in the length direction, but the inner diameter expanded by 3.9%. Therefore, the result was that it did not come into close contact with the wooden tube at all. On the other hand, Chu
When the tubular body is re-blown in the transverse direction and stretched, the heat shrinkage rate of the tube (when the stretching ratio is 1.2 to 2.0 times) is up to 22.4% in the length direction. Expanded, inner diameter 11.0
The shrinkage was ~38.8%, and the adhesion to the wooden cylinder was good. In addition, when tested at a stretching ratio of more than 2.0 times,
There were problems with workability, such as the tube bursting. In addition, these tables also show comparative data on heat shrinkability between electron beam irradiated elastomer tubes and commercially available soft polyvinyl chloride (PVC) tubes. Next, the temperature dependence of the thermal contraction rate of the electron beam irradiation tube (gel fraction 90%, dose 10 Mrad) stretched 1.5 times in the transverse direction was investigated. The results are shown in Table 2. From Table 2, the shrinkage rate in the inner diameter direction of the tube shows that there is almost no shrinkage at 40°C, but at 60°C
In the temperature range exceeding 90℃, the shrinkage rate increases linearly as the temperature increases, and the shrinkage rate is 15.0%.
/60°C to 30.0%/90°C, and the shrinkage rate at 100°C was almost the same as that at 90°C, confirming that the thermal shrinkage rate in a low-temperature atmosphere is excellent. Next, we will compare and contrast electron beam irradiation tubes with electron beam irradiated elastomer tubes and commercially available soft polyvinyl chloride (PVC) tubes, and examine their physical properties, hot water resistance, and heat resistance. and tested for chemical resistance. The results are shown in Tables 3 and 4. From Tables 3 and 4, it was confirmed that the dimensions of the elastomer tubes irradiated with the electron beam according to the present invention hardly changed in terms of hot water resistance and heat resistance. On the other hand, the comparative example of the electron beam irradiated elastomer tube and the commercially available soft PVC tube showed a large change. In addition, in terms of chemical resistance (organic solvent resistance), the electron beam irradiated elastomer tube of the present invention showed stability, but the electron beam irradiated elastomer tube of the comparative example and the commercially available Soft PVC tubes had problems such as melting. Next, the elastomer tube irradiated with electron beams will be compared and contrasted with elastomer tubes irradiated with electron beams and commercially available soft polyvinyl chloride (PVC) tubes, and the coefficient of friction between each base material will be determined. Measurements were made. The results are shown in Tables 3 and 4. As shown in Tables 3 and 4, the elastomer tube irradiated with electron beams has a higher coefficient of friction with each base material than the soft PVC sheet shown in the comparative example, and is less likely to slip. I understand. The friction coefficient is
Even when irradiated with electron beams, no particular problems such as slipperiness occurred. [Table 1]
Table 1


Unit % Lateral stretching Electron beam final irradiation
Electron beam irradiation
PVC Magnification (times) Length direction Inner diameter direction
Length direction Inner diameter direction Length direction Inner diameter direction
1.0 10.0
-5 11.5 -3.9
4.3 -2.8 1.2
2.6 16.6
0 11.0 2.4
1.5 1.5 -2
．． 6 30.4 -11.4
26.1 -1.0 7
．． 4 2.0 -14.3
41.4 -22.4 38
．． 8 -10.2 21.2 Notes; Stretching temperature: 60°C Shrinking temperature/time: 80°C/1
0 second cooling temperature/temperature: 20°C/10 seconds [Table 2]
Table 2 Ambient temperature ℃
40 50 60 70
80 90 100 Tube shrinkage rate (%) Length direction 0 0
0 -8.0 -11.4 -15.
0 -15.0 Tube shrinkage rate (%) Inner diameter 1.0
3.0 15.0 21.0 26.1
30.0 30.0 0020 [Table 3]
Table 3
fruit
Example No.
item
1 2
3 4 Electron beam irradiation dose 5
10 20
10 (Mrad)

Gel fraction
(wt%) 70
80 90
80 Tube lateral blow-up ratio 1.5
1.5 1.5 1.5 Modulus 0℃ 170
180 200
180 (kg/cm2) 23℃
140 150
180 150 Heat shrinkage rate Tube length -3.0
-11.4 -8.5
0 (%) Inner diameter
30.0 26.1
27.0 11.0 Adhesion to base material Dryer O
O O
O Hot water O O
O O Coefficient of friction Copy paper 0.63/0.69
0.62/0.65 0.61/0.66
0.62/0.65
Work gloves 0.60/0.65 0
．． 62/0.65 0.61/0.65 0
．． 62/0.65 hot water resistance
Not deformed Not deformed Not deformed
Heat resistant without deformation
Slightly deformed No deformation No deformation No deformation Chemical resistance Boiling point (wt%) 32/3
4/23 21/26/20 10/12/10
21/26/20 Room temperature
O O O ◎ ◎ ◎ ◎
◎ ◎ ◎ ◎ ◎ Note: The coefficient of friction indicates the value of μk/μs for both copy paper and work gloves. The same goes for Table 4. Chemical resistance values are for toluene/triclene/MEK. The same goes for Table 4. [Table 4]
Table 4
Example No.
Comparison example no. Item 5
1 2
Electron beam irradiation dose
10 0
0 (Mrad)


Gel fraction (wt%) 80
0 0
Lateral blow-up ratio of tube 2.0
1.5 1.5
modulus
0℃ 180 17
0 3800 (kg/cm2)
23℃ 150 140
370
Heat shrinkage rate Tube length -22.4
-2.6 -1.0 (
%) Inner diameter 38.8
30.4 7.4
Adhesion to base material Dryer O
O △
Hot water O
O △
Coefficient of friction Copy paper
0.62/0.65 0.63/0.69
0.61/0.66 Work gloves 0.62/0.65 0.60/
0.65 0.61/0.65
Hot water resistance
Not deformed Deformed Not deformed
Heat-resistant
Not deformed Deformed Not deformed Chemical resistance Boiling point (wt%) 21/26/2
0 100% dissolved Same as left
Room temperature ◎ ◎ ◎ ×
x x x x x
[0022] As described above, according to the present invention, it exhibits excellent heat shrinkability in the diametrical direction, has excellent heat shrinkage in a low-temperature atmosphere, and has excellent slip resistance and flexibility. ,
It was possible to provide a tube that has excellent workability for attaching and removing the tube when it is peeled off from the attached body using a cutter or the like for replacement or the like. Furthermore, according to the present invention, it has been possible to improve the heat resistance and chemical resistance of the tube while providing such excellent performance. The tube according to the present invention can be used not only for the various rollers mentioned above, but also for use as a grip member on the handles of fishing rods, golf clubs, baby carriages, tools, etc., and for paper feeders in office machines. It can also be used when a tube is attached to a shaft as a roll member in a roll.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of one form of a tube and one mode of use thereof showing an embodiment of the present invention,

FIG. 2 is an explanatory diagram of a tube molding example showing an embodiment of the present invention;

FIG. 3 is an explanatory diagram of a tube molding example showing an embodiment of the present invention;

[Explanation of symbols]

1 Tube extruder 2 Aquarium ３　　　　Collection roll 4 Tubular body 5 Hot water tank 6. Feeding side nip roll 7 Take-up nip roll 8 Collection roll 9 Cooling tank 10 Heat shrinkable tube 11　Object to be attached E Electron beam irradiation device

Claims (3)

[Claims] Claim 1: Ethylene-propylene-diene copolymer 3
0 to 70% by weight, and 70 to 30% by weight of an ethylene-vinyl acetate copolymer (vinyl acetate content: 5 to 30% by weight), and the gel fraction indicates the degree of crosslinking. 1. A heat-shrinkable tube characterized in that it is formed by heating and stretching a tube-like body having a carbon content of 70 to 95% by weight in the diametrical direction as well as in the longitudinal direction. Claim 2: The tube can be attached to the tube-attached body by heat shrinking, and the tube-attached body is covered with a coating that can be removed from the tube-attached body when necessary. The heat-shrinkable tube according to claim 1, which is a material. Claim 3: Ethylene-propylene-diene copolymer 3
A tubular body made of a thermoplastic elastomer composition containing 0 to 70% by weight and 70 to 30% by weight of an ethylene-vinyl acetate copolymer (vinyl acetate content 5 to 30% by weight) is crosslinked. The tube-shaped body is cross-linked so that the gel fraction is 70 to 95% by weight, and gas is blown into the tube-like body in the diametrical direction relative to the length direction. 1. A method for producing a heat-shrinkable tube, comprising heating and stretching at a stretching ratio of .