JP2008126467A - Elastic tube and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an elastic tube and a manufacturing method for the elastic tube which is stable against all hydrocarbon solvents including chemicals and a polar solvent, has no swelling, infiltration and adsorption by a chemical and a solvent, has little contamination due to an eluted matter eluted from a tube, enables liquid transportation in a clean state, is superior in bendability and flexibility, has no uneven thickness and parting line, and is excellent in strength. <P>SOLUTION: The elastic tube where liquid perfluoropolyether fluororubber composition is casted into a cavity of a casting mold 1 where the cavity 4 having circular ring shape cross section is formed by inserting a round rod shape core 3 in a cylindrical casting mold body 2, molded and cured to have no parting line on the appearance, and the manufacturing method for the elastic tube where liquid perfluoropolyether fluororubber composition is casted into a cavity of the casting mold where the cavity having circular ring shape cross section is formed by inserting the round rod shape core in the cylindrical casting mold body, molded and cured to have no parting line on the appearance are provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an elastic tube and a method for producing the same, and in particular, a liquid perfluoropolyether-based fluororubber composition having good solvent resistance, chemical resistance, heat resistance, and low temperature characteristics and durability. Elastic tube used for a wide range of applications such as piping members for transportation of gases, chemicals and solvents, industrial piping members, etc., which have no uneven thickness, no parting line, and excellent strength, and a method for producing the same It is about.

  Silicone rubber is generally excellent in chemical resistance and heat resistance, and is relatively easy to mold. Therefore, instead of polyvinyl chloride, which has poor oil resistance and steam resistance, medical catheters, industrial use, etc. In many fields, silicone rubber tube molded products are used. However, the silicone rubber tube has inconveniences such as penetration and adsorption of a solution such as a hydrocarbon solution and a ketone solution.

  General silicone rubber is inferior in oil resistance, and particularly swelled with hydrocarbon-based gasoline and other fuel oils, and since the strength decreases with swelling, it could not be used in those environments. Therefore, a fluororesin tube having excellent chemical resistance and fuel resistance has been developed. However, the fluororesin tube has a problem in handling because it is less flexible, hard, and lacks flexibility. In addition, the fluororubber tube is difficult to mold and has problems such as insufficient strength with respect to hot strength, polar solvent, amine solvent, and steam resistance.

  Furthermore, in the molding method, when a split mold is used, there is a problem of strength, dimensional accuracy, deburring, and the like because the molded product has a parting line in the appearance.

  In addition, for silicone rubber-based tubes, low-molecular siloxanes generated from silicone rubber may be extracted by chemicals, solvents, etc., so-called siloxane troubles that contaminate the transport liquid occur, and the use is limited. End up.

In addition, as a well-known document relevant to this invention, there exist the following.
Japanese Patent Laid-Open No. 02-308441 JP 07-256780 A JP 2000-290430 A

  The present invention has been made in view of the above circumstances. Due to the excellent solvent resistance and chemical resistance of the perfluoropolyether fluorine-containing rubber composition, all hydrocarbon solvents including chemicals and polar solvents can be used. In contrast, it is stable, does not swell, penetrate, and adsorb in chemicals and hydrocarbon solvents, and is not contaminated by the eluate from the tube. It is an object of the present invention to provide an elastic tube excellent in properties, free from uneven thickness and parting lines, and excellent in strength, and a method for producing the same.

  As a result of intensive studies to achieve the above object, the present inventors made a perfluoropolyether-based fluorine-containing rubber composition containing silica as a filling reinforcing agent and molded it with a specific casting mold. The tube structure with good dimensional accuracy without the parting line is stable to all hydrocarbon solvents including chemicals and polar solvents, and swelling, penetration and adsorption with chemicals and hydrocarbon solvents can be seen. In addition, it has been found that an elastic tube with excellent contamination and flexibility can be obtained while being able to convey clean liquid with little contamination by the eluate from the tube. It came to an eggplant.

Therefore, this invention provides the following elastic tube and its manufacturing method.
[1] Liquid perfluoropolyether-based fluororubber composition in the cavity of the casting mold in which a cavity with a circular cross section is formed by inserting a round bar core into the cylindrical casting mold body An elastic tube with no parting line in its appearance, characterized by being injected, molded and cured.
[2] Liquid perfluoropolyether-based fluororubber composition in the cavity of the casting mold in which a cavity with a circular cross-section is formed by inserting a round bar-shaped core into the cylindrical casting mold body A method for producing an elastic tube having no parting line in its appearance, characterized by injecting, molding and curing an object.
In this case, the fluorine-containing rubber composition is preferably injected, molded and cured in a state where tension is applied to the core in the cylindrical casting mold main body.
Incidentally, the crosslinking sites of the liquid perfluoropolyether fluorine-containing rubber composition, a Si-CH = CH _2, it is preferred that the crosslinking system is an addition-crosslinking or peroxide crosslinking.

  The elastic tube of the present invention is made of a perfluoropolyether-based fluorine-containing rubber composition having excellent solvent resistance, so that it has excellent solvent resistance, no elution of low molecular components in the transport solvent, and a uniform thickness. Because it has no parting line, it has excellent durability, so it can be used in a wide range of fields that require liquid transportation of clean solvents and chemicals including electric and electronic, and its industrial use. Great value.

  The elastic tube of the present invention can be obtained by molding using a perfluoropolyether-based fluorine-containing rubber composition as a material and a casting mold described later.

The perfluoropolyether-based fluorine-containing rubber composition according to the present invention is preferably a crosslinkable perfluoropolyether-based fluorine-containing rubber composition. In this case, the crosslinking site of the fluorine-containing rubber composition is Si—CH. = CH ₂ and the crosslinking system is addition reaction crosslinking or peroxide crosslinking is preferred.

The perfluoropolyether-based fluorine-containing rubber composition in which the crosslinking site used in the present invention is Si—CH═CH ₂ is disclosed in Japanese Patent Nos. 2990646, 2000-007835, and 2001-106893. It is described in detail in Japanese Patent Laid-Open No. 2003-201401 and the like, and is generally available as a trade name SIFEL series (Shin-Etsu Chemical Co., Ltd.).

The perfluoropolyether-based fluorine-containing rubber composition will be described in detail.
(A) a perfluoro compound having at least two alkenyl groups in the molecule and having a divalent perfluoroalkylene structure or a divalent perfluoropolyether structure in the main chain;
(B) A reinforcing filler, and (C) a crosslinking agent having a hydrosilyl group in the molecule or a peroxide crosslinking agent having a sufficient amount to cure the component (A) are suitable. .

［式中、Ｘは−ＣＨ₂−、−ＣＨ₂Ｏ−、−ＣＨ₂ＯＣＨ₂−又は−Ｙ−ＮＲ−ＣＯ−（Ｙは−ＣＨ₂−又は下記構造式（Ｚ）

（ｏ，ｍ又はｐ位）で示される基）
で表される基、Ｒは水素原子、メチル基、フェニル基又はアリル基、Ｘ’は−ＣＨ₂−、−ＯＣＨ₂−、−ＣＨ₂ＯＣＨ₂−又は−ＣＯ−ＮＲ−Ｙ’−（Ｙ’は−ＣＨ₂−又は下記構造式（Ｚ’）

（ｏ，ｍ又はｐ位）で示される基）
で表される基であり、Ｒは上記と同じである。ａは独立に０又は１、Ｌは２〜６の整数、ｂ及びｃはそれぞれ０〜２００の整数である。］ Of particular importance is the polymer of the component (A), and the component (A) is preferably a linear fluoropolyether compound represented by the following general formula (1).

[Wherein, X is _{-CH 2 -, - CH 2 O} -, - CH 2 OCH 2 - or -Y-NR-CO- (Y is -CH ₂ - or the following structural formula (Z)

(Group represented by o, m or p position)
R is a hydrogen atom, methyl group, phenyl group or allyl group, X ′ is —CH ₂ —, —OCH ₂ —, —CH ₂ OCH ₂ — or —CO—NR—Y ′ — (Y 'Is -CH ₂ -or the following structural formula (Z')

(Group represented by o, m or p position)
R is the same as above. a is independently 0 or 1, L is an integer of 2 to 6, and b and c are integers of 0 to 200, respectively. ]

  Examples of the reinforcing filler of the component (B) include fumed silica, wet silica, pulverized silica, calcium carbonate, diatomaceous earth, carbon black, various metal oxide powders, and the like. It may be processed. Among these, fumed silica is particularly preferable from the viewpoint of improving mechanical strength, and further, fumed silica treated with a silane-based surface treatment agent is preferable from the viewpoint of improving dispersibility.

  (B) As an addition amount of the reinforcing filler of a component, 1-200 mass parts is preferable with respect to 100 mass parts of (A) component. In particular, 5 to 100 parts by mass is preferable from the viewpoint of stability of mechanical properties. If the addition amount of the reinforcing filler is too small, the mechanical strength may be lowered, and if it is too much, the fluidity is lowered, and there may be a problem in moldability such as air mixing.

  Component (C) is a crosslinking agent that cures the polymer of component (A), and can be broadly classified into (i) a crosslinking agent capable of addition reaction having a hydrosilyl group in the molecule, or (ii) a peroxide crosslinking agent.

  When the addition reaction is performed using a crosslinking agent capable of addition reaction of component (C), an organosilicon compound having at least two hydrogen atoms (SiH groups) bonded to a silicon atom in one molecule is required. From the viewpoint of compatibility with the component A), dispersibility, and uniformity after curing, those having one or more fluorine-containing groups in one molecule are preferable.

  Furthermore, when performing addition reaction crosslinking, a catalyst that promotes the addition reaction between the alkenyl group and the hydrosilyl group in component (A) is required. This hydrosilylation reaction catalyst is generally a noble metal compound and is expensive. For this reason, platinum or platinum compounds that are relatively easily available are often used.

  When an organic peroxide is used as the component (C), the organic peroxide can be used without any particular limitation as it is usually used for curing a peroxide curable rubber composition. Specifically, for example, benzoyl peroxide, bis (2,4-dichlorobenzoyl) peroxide, di-t-butyl peroxide, 2,5-dimethyl-di-t-butylperoxyhexane, t-butyl peroxide Examples include benzoate, t-butyl peroxyisopropyl carbonate, and dicumyl peroxide. These may be used alone or in combination of two or more.

  Component (C) may be added in an amount sufficient to cure the polymer of component (A). Usually, in the case of addition crosslinking, the molar ratio of hydrosilyl group / alkenyl group is 0.5 to 2.0. More preferably, it is 0.8 to 1.5, and the amount of the hydrosilylation reaction catalyst used is preferably 0.1 to 1,000 ppm in terms of platinum group metal mass relative to component (A). . When using an organic peroxide, it is preferable to mix | blend 0.01-5 mass parts with respect to 100 mass parts of polymers of (A) component, More preferably, 0.05-3 mass parts is mix | blended.

  The viscosity of the liquid perfluoropolyether fluorine-containing rubber composition measured at 25 ° C. by a rotational viscometer is preferably in the range of 1 to 10,000 Pa · s, more preferably in the range of 10 to 5,000 Pa · s. When the viscosity is less than 1 Pa · s, the strength of the elastic tube may decrease, and when it exceeds 10,000 Pa · s, molding may be difficult.

  Next, the elastic tube of the present invention obtained by molding and curing the perfluoropolyether-based fluorine-containing rubber composition will be described with reference to the drawings. FIG. 1 is a schematic perspective view showing an example of the elastic tube shape of the present invention, and FIG. 2 is a schematic sectional view thereof. The elastic tube of the present invention is made of a cured product of the above perfluoropolyether-based fluorine-containing rubber composition and has no parting line.

The shape and dimensions of the elastic tube of the present invention are not particularly limited, but the inner diameter is preferably 5 mm or less, particularly preferably 3 mm or less, and preferably 1 mm or more, and the wall thickness is preferably 1 to 9 mm, particularly 2 to 6 mm.
Further, the elastic tube of the present invention preferably has an uneven thickness of 0.1 mm or less, particularly 0.05 mm or less.

  Such an elastic tube can be molded using a casting mold 1 as shown in FIG. In this mold, a circular bar-shaped cavity 4 is formed by inserting a round bar-shaped core 3 into a cylindrical casting mold body 2. In FIG. 3, 5 and 6 are fixing portions of the core 3, 7 is a core pulling mechanism portion, and the lower core fixing portion 5 and the upper core fixing portion 6 connect the core 3. While holding, fixing, firmly fixing the core 3 to the lower core fixing portion 5 at the time of material injection, molding and curing, the core 3 is strongly pulled by the core pulling mechanism portion 7, and tension is applied, The core 3 is not deformed by the pressure from the material at the time of material injection, and there is no eccentricity in the whole or locally, and the core 3 is maintained at the center in the cylindrical casting mold body 2. To do. Thereby, an elastic tube without uneven thickness can be formed. In addition, 8 is a material injection port, 9 is an air discharge port.

  As a method for forming the elastic tube, the perfluoropolyether-based fluorine-containing rubber composition is injected from the material injection port 8, whereby the air in the cavity 4 is excluded from the air discharge port 9, and the material fills the mold. After that, the inlet 8 and the outlet 9 are closed and heat-treated in an oven. After the heat treatment, the molded product is taken out from the oven, cooled and taken out from the mold to complete the molding.

In the present invention, as described above, by applying tension to the core 3 in the cylindrical casting mold main body 2, the core 3 is not deformed by the material pressure when the material (composition) is injected. Therefore, an elastic tube free from uneven thickness can be obtained.
The above material (composition) is generally greater than 0 kgf / cm ^2, it is injected into the cavity at a particular 0 kgf / cm ² greater than 100 kgf / cm ² or less pressure. On the other hand, the core, 0 kgf / greater than cm ² 10,000kgf / cm ² or less, the core be pulled strongly upward in FIG. 3 in particular over the tension of 1kgf / cm ² ~1,000kgf / cm ² preferable.

The heat treatment conditions in the oven are preferably 150 to 200 ° C., particularly 180 to 200 ° C. for 30 minutes to 90 minutes, particularly 40 minutes to 60 minutes. Moreover, as cooling conditions, it may cool by any means, such as standing at room temperature, water cooling, and air cooling.
In molding, a mold release agent may be used to improve the mold releasability between the molded product and the mold.

  The elastic tube thus obtained is formed of a perfluoropolyether-based fluorine-containing rubber, has no parting line, has an uneven thickness of 0.1 mm or less, and has a strength that can withstand solvent, external stress, and the like. The same chemical resistance and solvent resistance can be obtained regardless of the tube thickness.

  The elastic tube of the present invention can be used for various applications. In other words, parts that require flexibility, oil resistance, chemical resistance, and heat resistance, such as fuel transfer piping, medical catheters, printer ink transfer piping members, machine tool cutting oil piping members, etc. can be used widely. .

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.

Rubber materials and production equipment used in examples and comparative examples (perfluoropolyether-based fluorine-containing rubber materials)
Fluorine-containing rubber composition (I): SIFEL 3400 (A / B) (manufactured by Shin-Etsu Chemical Co., Ltd., liquid two-component type composition standard formulation): addition reaction crosslinking, (I) crosslinking site Si—CH═CH ₂
Fluorine-containing rubber composition (II): SIFEL 3155 (manufactured by Shin-Etsu Chemical Co., Ltd., liquid one-component type composition standard formulation): addition reaction crosslinking, (II) crosslinking site Si—CH═CH ₂

(Silicone rubber composition)
Silicone rubber composition (I): KE1950-40 (A / B) (manufactured by Shin-Etsu Chemical Co., Ltd., standard composition of liquid two-component composition)
Silicone rubber composition (II): KE1935 (A / B) (standard composition of liquid two-component composition manufactured by Shin-Etsu Chemical Co., Ltd.)

(Curing equipment)
・ High temperature curing oven (mold)
As the tube, a die body designed for forming a tube with an outer diameter of 5 mm, an inner diameter of 2 mm, a wall thickness of 1.5 mm, and a length of 200 mm and a core with an outer diameter of 2 mm and a length of 300 mm are used.

[Example 1]
In order to obtain a molded article having the structure shown in FIG. 1, the mold shown in FIG.
After fixing the tube inner diameter forming core in the unheated mold body under a tension of 10 kgf / cm ^2, a fluorine-containing rubber composition; SIFEL 3400 (A / B) ( Shin-Etsu Chemical Co., Ltd., liquid two-component type composition standard composition) material is injected at a pressure of 2 kgf / cm ² , and after the discharge of the liquid material is seen from the air outlet, the material injection is completed, Next, the material was cross-linked by heating for 40 minutes in an oven set at 200 ° C. with the material inlet and air outlet of the mold closed. After cooling, the tube molded product was taken out from the mold and post-cured at 200 ° C. for 4 hours to obtain the elastic tube of the present invention.

[Example 2]
As in Example 1, after fixing the core for forming the tube inner diameter in the unheated mold body under a tension of 10 kgf / cm ² , the fluorine-containing rubber composition from the material injection port; SIFEL 3155 (Shin-Etsu Chemical Co., Ltd., liquid one-component type composition standard composition) Material is injected at a pressure of 2 kgf / cm ² , and after the discharge of the liquid material is seen from the air outlet, the material injection is completed. Subsequently, the material injection port and the air discharge port of the mold were closed and heated for 40 minutes in an oven set at 200 ° C. After cooling, the tube molded product was taken out from the mold and post-cured at 200 ° C. for 4 hours to obtain the elastic tube of the present invention.

[Comparative Example 1]
In the unheated split mold shown in FIG. 4, after fixing the tube inner diameter molding core without applying tension, a fluorine-containing rubber composition; SIFEL 3155 (manufactured by Shin-Etsu Chemical Co., Ltd., Standard composition of liquid one-component type composition) The materials were charged and subjected to heat crosslinking by press molding at a press temperature of 150 ° C., a press pressure of 50 kgf / cm ² and a press time of 20 minutes. Thereafter, the tube molded product was taken out from the mold and post-cured at 200 ° C. for 4 hours to obtain an elastic tube having a parting line.
In FIG. 4, 11 is an upper mold, 12 is a lower mold, 13 is a split part, and 14 is a core.

[Comparative Example 2]
Using the mold shown in FIG. 3, the production was performed in the following steps.
After fixing the tube inner diameter forming core in the unheated mold body under a tension of 10 kgf / cm ² , it has the same hardness as SIFEL 3400 used in Example 2 from the material injection port. Silicone rubber composition: KE-1950-40 (A / B) (manufactured by Shin-Etsu Chemical Co., Ltd., liquid two-component type) Material is injected at a pressure of 2 kgf / cm ² , and the liquid material is discharged from the air outlet. After being seen, the material injection was completed, and the material was cross-linked for 40 minutes in an oven set at 200 ° C. with the material inlet and air outlet of the mold closed. After cooling, the tube molding was taken out from the mold and post-cured at 200 ° C. for 2 hours to obtain a silicone elastic tube.

[Comparative Example 3]
Using the mold shown in FIG. 3, the production was performed in the following steps.
After fixing the tube inner diameter forming core in the unheated mold body with a tension of 10 kgf / cm ² , the core has the same hardness as SIFEL 3155 used in Example 2 from the material inlet. Silicone rubber composition: KE-1935 (A / B) (manufactured by Shin-Etsu Chemical Co., Ltd., liquid two-component type) Material is injected at a pressure of 2 kgf / cm ² , and the liquid material is discharged from the air outlet. Thereafter, the material injection was completed, and the material was injected and crosslinked in an oven set at 200 ° C. for 40 minutes with the material inlet and air outlet of the mold closed. After cooling, the tube molded product was taken out from the mold and post-cured at 200 ° C. for 2 hours to obtain a silicone elastic tube.

[Method of evaluating the permeability of the solution into the tube]
The tube obtained with the fluorine-containing rubber composition of Example 2 and Comparative Example 1 and the silicone rubber composition of Comparative Examples 2 and 3 was colored with a dye (Oil Blue (II) N Orient Chemical Co., Ltd.). After filling with toluene and leaving to stand at room temperature for 1 day, the colored state of the inner surface of the tube was observed.
None: Almost no discoloration due to penetration of the coloring solution.
Existence: Discoloration is observed in the tube due to penetration of the coloring solution.

[Solvent resistance evaluation method]
For tubes obtained with the fluorine-containing rubber compositions of Examples 1 and 2 and Comparative Example 1 and the silicone rubber compositions of Comparative Examples 2 and 3, hydrocarbon solvent gasoline, toluene, ketone solvent acetone, ester After being immersed in ethyl acetate as a solvent for 3 days, the volume change rate was measured by the following calculation formula and summarized in Table 1.
(Volume change rate calculation formula)-Conforms to JIS K6301

[Evaluation method of tube thickness deviation]
The thicknesses of the four diagonal portions of the tube cross sections obtained in Examples 1 and 2 and Comparative Examples 1 to 3 were measured, and the maximum value, minimum value, and thickness difference of the thicknesses are summarized in Table 1. .
Measurement location:
Four-point measuring machine diagonally with respect to the tube cross section shown in FIG.
Peacock [Ozaki Mfg. Co., Ltd.] Dial Pipe Gauge

[Evaluation of rubber properties]
The rubber physical properties of the cured rubber products obtained in the above Examples and Comparative Examples were measured according to JIS K6249, and the results are summarized in Table 1.

As a result, the elastic tube according to the present invention, which is made of a perfluoropolyether-based fluorine-containing rubber composition and molded using a cylindrical casting mold, has no solvent permeation and is contaminated with the transport chemical solvent. As a result, the solvent resistance is excellent, and the tube thickness is uniform and there is no parting line in the appearance.
On the other hand, as shown in the comparative example, with silicone rubber, even if the wall thickness is uniform, the penetration of the solvent into the tube and the volume change rate are large, so the durability is inferior and the carrier solvent is contaminated. I understand that.

It is a schematic perspective view which shows an example of the elastic tube shape of this invention. It is a schematic sectional drawing which shows an example of the elastic tube shape of this invention. It is the schematic which shows an example of the liquid mold structure used for the elastic tube shaping | molding of this invention. It is the schematic which shows the split mold which has a parting line in the tube after the shaping | molding used in the comparative example 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Casting die 2 Cylindrical casting mold main body 3 Core 4 Cavity 5 Core fixing part 6 Core fixing part 7 Core pulling mechanism part 8 Material injection port 9 Air discharge port

Claims (9)

  A liquid perfluoropolyether-based fluorine-containing rubber composition is inserted into the cavity of the casting mold in which a circular ring-shaped cavity is formed by inserting a round bar-shaped core into the cylindrical casting mold body, An elastic tube with no parting line in its appearance, characterized by injection, molding and curing. _2. The elastic tube according to claim 1, wherein the crosslinking site of the liquid perfluoropolyether-based fluorine-containing rubber composition is Si—CH═CH ₂ , and the crosslinking system is addition reaction crosslinking or peroxide crosslinking. . The liquid perfluoropolyether-based fluorine-containing rubber composition is
(A) a perfluoro compound having at least two alkenyl groups in the molecule and having a divalent perfluoroalkylene structure or a divalent perfluoropolyether structure in the main chain;
(B) Reinforcing filler, and (C) Addition-reactive cross-linking agent or peroxide cross-linking agent having a hydrosilyl group in the molecule: an amount sufficient to cure the component (A). The elastic tube according to claim 1 or 2. (A) component is the following general formula (1)

[Wherein, X is _{-CH 2 -, - CH 2 O} -, - CH 2 OCH 2 - or -Y-NR-CO- (Y is -CH ₂ - or the following structural formula (Z)

(Group represented by o, m or p position)
R is a hydrogen atom, methyl group, phenyl group or allyl group, X ′ is —CH ₂ —, —OCH ₂ —, —CH ₂ OCH ₂ — or —CO—NR—Y ′ — (Y 'Is -CH ₂ -or the following structural formula (Z')

(Group represented by o, m or p position)
R is the same as above. a is independently 0 or 1, L is an integer of 2 to 6, and b and c are integers of 0 to 200, respectively. ]
The elastic tube according to claim 3, which is a linear fluoropolyether compound represented by the formula:   Liquid perfluoropolyether-based fluorine-containing rubber composition is injected into the cavity of the casting mold in which a circular ring-shaped cavity is formed by inserting a round bar-shaped core into the cylindrical casting mold body. A method for producing an elastic tube having no parting line in its appearance, characterized by being molded and cured.   6. The method for producing an elastic tube according to claim 5, wherein the fluorine-containing rubber composition is injected, molded and cured in a state where tension is applied to the core in the cylindrical casting mold main body. Crosslinking site of the liquid perfluoropolyether fluorine-containing rubber composition, a Si-CH = CH _2, according to claim 5 or 6, wherein the crosslinking system is an addition-crosslinking or peroxide crosslinking An elastic tube manufacturing method. The liquid perfluoropolyether-based fluorine-containing rubber composition is
(A) a perfluoro compound having at least two alkenyl groups in the molecule and having a divalent perfluoroalkylene structure or a divalent perfluoropolyether structure in the main chain;
(B) Reinforcing filler, and (C) Addition-reactive cross-linking agent or peroxide cross-linking agent having a hydrosilyl group in the molecule: an amount sufficient to cure the component (A). The method for producing an elastic tube according to claim 5, wherein the elastic tube is provided. (A) component is the following general formula (1)

[Wherein, X is _{-CH 2 -, - CH 2 O} -, - CH 2 OCH 2 - or -Y-NR-CO- (Y is -CH ₂ - or the following structural formula (Z)

(Group represented by o, m or p position)
R is a hydrogen atom, methyl group, phenyl group or allyl group, X ′ is —CH ₂ —, —OCH ₂ —, —CH ₂ OCH ₂ — or —CO—NR—Y ′ — (Y 'Is -CH ₂ -or the following structural formula (Z')

(Group represented by o, m or p position)
R is the same as above. a is independently 0 or 1, L is an integer of 2 to 6, and b and c are integers of 0 to 200, respectively. ]
The method for producing an elastic tube according to claim 8, which is a linear fluoropolyether compound represented by the formula:

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