JP5654260B2 - Multilayer tube - Google Patents

Description

  The present invention relates to a multilayer tube which does not have a problem of plasticizer bleeding.

  In the car body painting line, plasticized nylon tubes (PA11 or PA12) were initially used, but the paint easily adheres to the inner surface of the tube, and the plasticizer in the tube elutes into the fluid (paint or solvent). As a result, there have been problems in the durability (life) of the tube due to the deterioration of the coating itself and the occurrence of tube hardening and thinning.

  In order to solve the above problems, single-layer Teflon tubes (fluorine resin tubes) with excellent smoothness on the inner surface of the tube and less paint adhesion, and excellent chemical resistance (particularly solvent resistance) have come to be used. It was.

  However, although Teflon tubes have excellent characteristics in the above points, they are significantly inferior in flexibility, bending fatigue resistance, and wear resistance compared to plasticizer-containing nylon tubes. When used for piping such as sliding parts, cracks and cracks occur in the tube in a short period of time, which can easily lead to tube breakage troubles, and it is almost impossible to use a single-layer Teflon tube for moving parts, and the pipe is fixed. However, it has been limited to use under conditions where there is little movement of the portion that has been moved.

  In order to solve the above problems, a tube having a two-layer or three-layer structure in which a plasticized nylon resin and a fluororesin are combined has been developed, and is currently used as a paint tube for an automobile body (for example, patent document). 1).

  However, a tube using a plasticizer-containing nylon resin has a problem of bleeding of the plasticizer due to aging. In particular, the paint line environment of an automobile body has a high solvent atmosphere concentration and tends to facilitate bleeding of plasticizers. Also, because it is in an environment where the solvent is always handled, the solvent itself often scatters when an operation error or trouble occurs, and the solvent itself directly contacts or adheres to the nylon of the outer layer. Bleeding (precipitation) is further accelerated, tube hardening and thinning phenomenon are accelerated, leading to the same trouble as the single-layer Teflon tube described above.

  On the other hand, if the plasticizer of the nylon resin containing the plasticizer is omitted, since the plasticizer is not blended, the hardness becomes the same as that of the Teflon tube (fluororesin tube) and the flexibility is extremely reduced. The piping itself to the movable part and the sliding part of the robot, etc., becomes impossible, which leads to the same trouble as the single layer Teflon tube as well as the plasticizer bleeding tube.

JP 2005-315362 A (Claim 1, paragraphs 0021 and 0028)

  This invention makes it a subject to provide the multilayer tube which is rich in a softness | flexibility, without mix | blending a plasticizer.

The gist of the present invention is as follows.
(1) A hollow tube composed of a plurality of layers in the thickness direction, wherein the plurality of layers are, from the outside, an outer layer composed of a thermoplastic polyamide elastomer, an intermediate layer composed of an adhesive polyamide, A multilayer tube including an inner layer composed of an adhesive fluororesin.
(2) The multilayer tube according to (1), wherein the thermoplastic polyamide elastomer is a polyamide block copolymer comprising a hard segment composed of a polyamide component and a soft segment composed of a polyalkylene ether glycol component.
(3) The multilayer tube according to the above (1) or (2), which has an outermost layer composed of a thermoplastic polyamide elastomer and a thermoplastic polyether ester elastomer outside the outer layer.
(4) The multilayer according to (3), wherein the thermoplastic polyether ester elastomer is a multi-block polymer in which hard segments made of polybutylene terephthalate and soft segments made of terephthalic acid ester of polyalkylene ether glycol are alternately bonded. tube.
(5) The multilayer tube according to (3) or (4), wherein the outer surface of the outermost layer is formed in a satin finish.
(6) The multilayer tube according to the above (1) or (2), which has an outermost layer composed of a thermoplastic polyamide elastomer and a polymer type antistatic agent outside the outer layer.
(7) The multilayer tube according to any one of (1) to (6), which does not contain a plasticizer.
(8) The multilayer tube according to any one of (1) to (7), which is a paint pipe tube for coating, a beverage transport tube, a liquid food transport tube, a chemical transport tube or a clean room piping tube.

  In the present specification, the terms “resin”, “elastomer”, and “polymer / polymer (for example, polyamide)” are used not only as a single meaning but also as a meaning of a composition containing additives. is there.

  The multilayer tube of the present invention is a product with high cleanliness that does not contain a plasticizer in all of the resin raw materials used for the inner layer, intermediate layer, outer layer, etc. The trouble caused by can be solved. Since the multilayer tube of the present invention has clean properties that do not contain a plasticizer, in addition to piping tubes used for coating fluids (paints and solvents), tubes that do not cause environmental pollution, such as food-related It can also be used as a fluid tube, a clean room piping tube (fluid: clean air, refrigerant, solvent, etc.), or a transport tube for ink, oil, or the like.

FIG. 1 shows a three-layer tube comprising an inner layer, an intermediate layer and an outer layer. FIG. 2 shows a four-layer tube comprising an inner layer, an intermediate layer, an outer layer and an outermost layer. FIG. 3 shows an apparatus for producing a multilayer tube. FIG. 4 shows an outline of the surface slip test. FIG. 5 shows an outline of a method for measuring the water contact angle. FIG. 6 shows an outline of a tube single body tensile property test after the entire surface is immersed. FIG. 7 shows an outline of the minimum bending radius measurement test. FIG. 8 shows an outline of the flexibility test. FIG. 9 shows a test apparatus for measuring the amount of helium leak using the vacuum vessel method. FIG. 10 shows the relationship between the tube length of the four-layer tube of Example 2 and the two-layer tube of Comparative Example 1 and the helium leak rate (including the helium leak rate of the joint).

  The multilayer tube of the present invention is a hollow tube composed of a plurality of layers in the thickness direction. Further, the plurality of layers include, from the outside, an outer layer made of thermoplastic polyamide elastomer, an intermediate layer made of adhesive polyamide, and an inner layer made of adhesive fluororesin. The multilayer tube of the present invention may have an outermost layer composed of a thermoplastic polyamide elastomer and a thermoplastic polyetherester elastomer or a polymer-type antistatic agent outside the outer layer.

[Inner layer]
The inner layer is made of an adhesive fluororesin.

The adhesive fluororesin in the present invention has a melting point of 150 to 250 ° C., and Lexpearl RA3150 (made by Nippon Polyethylene Co., Ltd.), which is a kind of modified olefin resin, and fluororesin is 4 × 10 ^{5 to} 5 × 10. ^A laminated sheet was produced by pressing at ⁵ Pa sample pressure at 240 ° C. for 10 minutes, and a sample collected by cutting to a width of 2.5 cm and a length of 25 cm was peeled off by a method according to JIS Z0237. A fluororesin having a 180 degree peel strength of 4 N / cm or more when a 180 degree peel strength is measured at a speed of 5 mm / min and a temperature of 23 ° C.

Moreover, the IR spectrum of the adhesive fluororesin in the present invention has an absorption peak between 1780-1880 cm ⁻¹ . Preferably, the IR spectrum of the adhesive fluororesin has an absorption peak due to an anhydride such as a maleic anhydride group between 1790 and 1800 cm ⁻¹ and between 1845 and 1855 cm ⁻¹ , or 1800 has an absorption peak due to end carbonate groups during 1815Cm ^-1, or between 1790～1800Cm ^-1, during and between 1800～1815Cm ^-1 of 1845～1855Cm ^-1, maleic groups such as anhydrous Have an absorption peak due to a mixture of anhydride and terminal carbonate groups.

More preferably, the IR spectrum of the adhesive fluororesin has an absorption peak due to an anhydride such as a maleic anhydride group between 1790 and 1800 cm ⁻¹ and between 1845 and 1855 cm ⁻¹ , or 1800 It has an absorption peak due to the terminal carbonate group between ˜1815 cm ⁻¹ .

In addition, the ratio of the height of the absorption peak between 1790 and 1800 cm ⁻¹ due to an anhydride such as a maleic anhydride group to the height of the absorption peak near 2881 cm ⁻¹ due to the CH ₂ group of the main chain is 0.5 to 1.5, preferably 0.7 to 1.2, and more preferably 0.8 to 1.0.

The ratio of the height of the absorption peak between 1800 and 1815 cm ⁻¹ due to the terminal carbonate group to the height of the absorption peak near 2881 cm ⁻¹ due to the CH ₂ group of the main chain is 1.0 to 2.0, preferably 1.2 to 1.8, more preferably 1.5 to 1.7.

  As such a fluororesin having adhesive strength, for example, a homopolymer or copolymer having a tetrafluoroethylene unit, such as a carbonate group, a carboxylic acid halide group, a hydroxyl group, a carboxyl group, or an epoxy group at the terminal or side chain A resin having a functional group of A plurality of resins may be mixed as long as the melting point and the adhesive strength are expressed. Examples of commercially available fluororesins having adhesive strength as described above include Neoflon EFEP (manufactured by Daikin Industries) and Fullon LM-ETFE AH2000 (manufactured by Asahi Glass Co., Ltd.).

  Fluororesin has excellent chemical resistance (organic solvent resistance) and low water absorption, making it ideal as a protective material.

  The thickness of the inner layer is, for example, about 0.01 to 1.0 mm, preferably about 0.01 to 0.5 mm, and more preferably about 0.02 to 0.3 mm.

[Middle layer]
The intermediate layer is made of an adhesive polyamide.

The adhesive polyamide in the present invention means one having a characteristic of strongly adhering mainly to an ETFE-based adhesive fluororesin. The adhesive polyamides, such as unplasticized type polyamide 11 (PA11), unplasticized type polyamide 12 (PA12), Polyamide 6/12 (PA6 / 12), a plasticizer containing polyamide 11, include a plasticizer containing polyamide 12 From the viewpoints of hardness, adhesive strength with fluororesin, and compatibility (adhesiveness) with the thermoplastic elastomer of the outer layer, non-plastic type polyamide 11 and non-plastic type polyamide 12 are preferred. Furthermore, in order to compensate for the disadvantages of the inner layer fluororesin which is inferior in bending fatigue resistance, non-plastic type polyamide 11 having about 6 times the durability of non-plastic type polyamide 12 in bending fatigue resistance is preferable. As the preferable adhesive polyamide 11, for example, Rilsan ^™ B and Rilsan ^™ G manufactured by Arkema, which are non-plastic type polyamide 11, are commercially available, and the commercially available products can be used.

  By using the intermediate layer composed of the adhesive polyamide 11, it is possible to strongly bond the outer layer composed of the thermoplastic polyamide 11 elastomer and the inner layer composed of the adhesive fluororesin. In addition, since the intermediate layer and the outer layer are both composed mainly of polyamide 11 and the crystal structure is a triclinic unit cell, they are easily compatible and fused with each other, and high adhesion is obtained. In addition, there is no problem such as peeling at a portion where movement such as movement or vibration is intense.

  The thickness of the intermediate layer is, for example, about 0.01 to 0.5 mm, preferably about 0.01 to 0.25 mm, and more preferably about 0.01 to 0.15 mm.

[Outer layer]
The outer layer is made of a thermoplastic polyamide elastomer.

  Examples of the thermoplastic polyamide elastomer include a polyamide block copolymer composed of a hard segment composed of a polyamide component and a soft segment composed of a polyalkylene ether glycol component. The polyamide component of the hard segment is selected from the group consisting of (1) lactam, (2) ω-amino aliphatic carboxylic acid, (3) aliphatic diamine and aliphatic dicarboxylic acid, or (4) aliphatic diamine and aromatic dicarboxylic acid. Specifically, lactams such as ε-caprolactam, ω-aminoaliphatic carboxylic acids such as 11-aminoundecanoic acid (PA11), 12-aminododecanoic acid (PA12), hexamethylenediamine, 1,7- Aliphatic diamines such as diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, and aliphatic dicarboxylic acids such as adipic acid And aromatic dicarboxylic acids such as terephthalic acid. Examples of the polyalkylene ether glycol constituting the soft segment of the polyamide-based block copolymer include polytetramethylene glycol, polyethylene glycol, poly-1,2-propylene glycol, and the like.

The melting point of the polyamide-based block copolymer is determined by the kind and ratio of the hard segment composed of the polyamide component and the soft segment composed of the polyalkylene ether glycol component. used. The polyamide-based block copolymer, for example, manufactured by Arkema Pebax ^{TM (Pebax TM)} are commercially available, it can be used the commercially available product.

  By using thermoplastic polyamide elastomer as a component of the outer layer, the flexibility of the adhesive non-plastic type polyamide resin used in the inner layer fluororesin and adhesive layer is compensated for the lack of flexibility and tremendous flexibility. And elasticity (restorability) is obtained as a tube. In addition, regarding the realization of flexibility, the so-called low molecular weight plasticizer is an elastomer type that does not cause trouble due to thinning or curing of the tube due to plasticizer bleeding, or other characteristics. Can also be maintained.

  When selecting performance such as mechanical properties, hardness, restorability, transparency, moldability, and flexibility as a tube, it is possible to select from various physical properties of each grade of thermoplastic polyamide elastomer, for example, The hardness of the thermoplastic polyamide elastomer can be selected from the range of Shore D26 to Shore D71, but considering the balance of various performances and molding characteristics of the tube, the hardness of the Shore D32 to Shore D68 is about The choice of grade is preferred.

  The thickness of the outer layer is, for example, about 0.2 to 6.0 mm, preferably about 0.3 to 5.0 mm, and more preferably about 0.4 to 4 mm.

[Outermost layer]
In the multilayer tube of the present invention, the outermost layer provided as necessary is composed of a thermoplastic polyamide elastomer and a thermoplastic polyetherester elastomer or a polymer type antistatic agent.

  A plastic tube generally has a smooth inner surface, and if it is smooth like a mirror-finished surface, it is slippery against the fluid (liquid or gas) in contact with it, and it is difficult for substances to adhere to it. However, if the outer surface of the tube is similarly smooth and mirror-finished, the phenomenon of the tubes sticking to each other (sticking) occurs, and the slipping property between the tubes is reduced. It tends to get worse.

  This tendency to become a sticking state is likely to occur not only for the same tubes but also for other system constituent materials such as resins and metals, and there is an increase in the contact area due to the smooth surface. As a factor, the coefficient of friction and the frictional resistance are increased, resulting in a decrease in the wear resistance of the tube.

  Therefore, for multiple piping tubes used for fluid (liquid or gas) piping in painting robots, etc., other components (tubes of the same material, tubes of other materials, cables such as electric wires) If there is a part that comes into contact with the tube guide, flexible hose, etc.) and the part is bent, stretched, stretched, twisted, or rubbed, the inner surface of the tube should be smooth to prevent pressure loss and material retention. However, the tube outer surface is finished with an appropriate roughness (pear texture, etc.) with reduced smoothness, and the tube with less contact area and contact resistance is more effective. It will be.

  However, in a three-layer tube in which the outer layer composed of the thermoplastic polyamide elastomer is the outer surface of the tube, it is difficult to form the outer surface of the tube in a satin shape while keeping the inner surface of the tube smooth (smooth). .

  By providing an outermost layer composed of a thermoplastic polyamide elastomer and a thermoplastic polyetherester elastomer on the outside of the outer layer of the three-layer tube, the outer surface of the tube can be formed into a satin finish.

  As the thermoplastic polyamide elastomer used for the outermost layer, the same thermoplastic polyamide elastomer used for the outer layer can be used.

  The thermoplastic polyether ester elastomer is not particularly limited as long as it is a thermoplastic elastomer mainly composed of polyester. For example, a hard segment made of polyester formed from an aromatic dicarboxylic acid or an ester-forming derivative thereof and a diol. And a block copolymer of a soft segment formed mainly from a polyether.

  The thermoplastic polyetherester elastomer preferably has a Shore D hardness (based on JIS K7215) of 45 to 75D, more preferably 50 to 65D, and a flexural modulus (based on ASTM D790) of preferably 90 to 600 MPa, More preferably, it is 150-400 MPa.

  The thermoplastic polyether ester elastomer may be used alone or in combination with two or more kinds of hardness for the purpose of obtaining necessary characteristics.

  Examples of the aromatic dicarboxylic acid or its ester-forming derivative used for the hard segment of the block copolymer include terephthalic acid, dimethyl terephthalate, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2, Examples include 7-dicarboxylic acid, diphenyl-4,4′-dicarboxylic acid, diphenoxyethanedicarboxylic acid, 5-sulfoisophthalic acid, or ester forming derivatives thereof, preferably terephthalic acid and / or dimethyl terephthalate.

  Examples of the diol used for the hard segment of the block copolymer include ethylene glycol, trimethylene glycol, tetramethylene glycol (1,4-butanediol), pentamethylene glycol, hexamethylene glycol, neopentyl glycol having a molecular weight of 300 or less. , Aliphatic diols such as decamethylene glycol, alicyclic diols such as 1,4-cyclohexanedimethanol and tricyclodecane dimethylol, xylylene glycol, 4,4′-dihydroxydiphenyl, 2,2-bis (4- Hydroxyphenyl) propane, 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane, bis (4-hydroxyphenyl) sulfone, bis (2-hydroxyphenyl) sulfone, bis [4- (2-hydroxy) Fragrances such as ethoxy) phenyl] sulfone, 1,1-bis [4- (2-hydroxyethoxy) phenyl] cyclohexane, 4,4′-dihydroxy-p-terphenyl, 4,4′-dihydroxy-p-quarterphenyl Group diol, preferably 1,4-butanediol.

  Examples of polyethers (polyoxyalkylenes) used in the soft segment of the block copolymer include poly (ethylene oxide) glycol, poly (propylene oxide) glycol, and poly (tetramethylene oxide) having a number average molecular weight of about 300 to 6000. Glycol, poly (hexamethylene oxide) glycol, ethylene oxide propylene oxide copolymer, poly (propylene oxide) glycol ethylene oxide addition polymer, ethylene oxide tetrahydrofuran copolymer, preferably poly (propylene oxide) glycol, poly (tetramethylene oxide) glycol Is mentioned.

  The production method of the block copolymer is not particularly limited and can be produced by a known method. For example, a hard segment is prepared by ester reaction or transesterification of dicarboxylic acid or dicarboxylic alcohol diester and glycol. , A method in which polyoxyalkylene glycol is added to effect transesterification to copolymerize the soft segment; a method in which the hard segment and the soft segment are subjected to an addition reaction, a method in which they are combined with a chain linking agent, or a method in which the respective reaction products are melt mixed Etc.

  The thermoplastic polyether ester elastomer is preferably a multi-block polymer in which hard segments made of polybutylene terephthalate and soft segments made of terephthalic acid ester of polyalkylene ether glycol are alternately bonded.

The preferable thermoplastic polyether ester elastomer has a hard segment represented by the following formula (I):
[—COC ₆ H ₄ CO—O (CH ₂ ) ₄ O—] _n
(In the formula, —COC ₆ H ₄ CO— represents a terephthaloyl group.)
The soft segment is represented by the following formula (II):
[—COC ₆ H ₄ CO—O {(CH ₂ ) _p O} _q −] _m
(In the formula, —COC ₆ H ₄ CO— represents a terephthaloyl group.)
Indicated by

As the preferable thermoplastic polyetherester elastomer, for example, Hytrel ^TM series (manufactured by Toray DuPont) is commercially available, and the commercially available product can be used.

For example, Hytrel ^TM 6377 has a Shore D hardness (based on JIS K7215) 63 and a flexural modulus (based on ASTM D790) 353 MPa, and can be suitably used as a thermoplastic polyetherester elastomer.

  The ratio (mass ratio) between the thermoplastic polyamide elastomer and the thermoplastic polyether ester elastomer in the outermost layer can provide an appropriate roughness (pear texture) of the outer surface of the tube during molding, and the thermoplastic polyamide elastomer It is necessary to increase the blending ratio of the thermoplastic polyamide elastomer in terms of maintaining the properties such as transparency and flexibility, and it is preferably 95/5 to 60/40, and 90/10 to 70/30. More preferably it is.

  Since the blended thermoplastic polyamide elastomer and thermoplastic polyether ester elastomer are melted together, the ether-based elastomer does not cause problems in terms of function and quality in molding.

  Further, when the outermost layer of the multilayer tube of the present invention is composed of a thermoplastic polyamide elastomer and a polymer type antistatic agent, it is particularly suitable as a piping tube for a two-component curable paint. That is, since the solvent used for cleaning the two-component curable paint is a special one, static electricity is likely to be generated, and thus the multilayer tube as described above is effective.

The polymer type antistatic agent may be any antistatic agent having a high molecular weight (for example, a number average molecular weight of 1000 or more), and is not particularly limited, but is usually an olefin block and / or a polyamide block and a hydrophilic block. And a block copolymer. Among these, in the present invention, from the viewpoint of compatibility with the thermoplastic polyamide elastomer, a master comprising a block copolymer of a polyamide block and a polyether block and a polymer type antistatic agent blended in both. A batch type is preferred. Such is a block polymer, for example, is described in JP-T-2003-508622, for example, manufactured by Arkema Pebax ^{TM (Pebax TM) MV1074, MV2080} , MH1657, MH2030 are commercially available, the use of the commercially available product Can do.

The addition amount of the polymer antistatic agent can be appropriately selected so that the volume resistivity of the outermost layer is in the range of about 1 × 10 ⁴ to 1 × 10 ¹² Ω · cm. For example, the ratio (mass ratio) between the thermoplastic polyamide elastomer and the polymer antistatic agent can be selected from the range of, for example, thermoplastic polyamide elastomer / polymer antistatic agent = 100/1 to 100/100, For example, it is 100/5 to 100/50, preferably 100/10 to 100/45, and more preferably about 100/15 to 100/40.

The volume resistivity of the outermost layer is, for example, 1 × 10 ⁴ to 1 × 10 ¹² Ω · cm, preferably 1 × 10 ⁵ to 1 × 10 ¹⁰ Ω · cm, and more preferably 5 × 10 ^{6 to} 5 × 10. It is about ⁹ Ω · cm.

  It does not specifically limit as a preparation method of the compound which comprises an outermost layer, A normal mixing or kneading method can be used. For example, a method of kneading various components in a heated and melted state using a kneader or mixer such as a single screw extruder, twin screw extruder, Banbury mixer, Brabender, Henschel mixer, open roll, kneader, etc. .

  The thickness of the outermost layer may be selected according to the application, but is, for example, 0.01 to 2 mm, preferably 0.01 to 1 mm, and more preferably about 0.01 to 0.5 mm.

  The elastomer constituting the outer layer or outermost layer of the multilayer tube of the present invention is a stabilizer (thermal stabilizer, antioxidant, light stabilizer), colorant (pigment, masterbatch, etc.) unless the object of the present invention is impaired. However, the total amount of these additives is preferably 5% by mass or less, and more preferably 3% by mass or less.

[Multilayer tube]
The multilayer tube of the present invention may have at least a plurality of layer structures including, from the outside, an outer layer made of thermoplastic polyamide elastomer, an intermediate layer made of adhesive polyamide, and an inner layer made of adhesive fluororesin. However, a four-layer structure in which an outermost layer composed of a thermoplastic polyamide elastomer and a thermoplastic polyether ester elastomer or a polymer type antistatic agent is provided on the outer side of the outer layer is preferable.

  The outer diameter and inner diameter of the multilayer tube of the present invention are not particularly limited and can be selected depending on the application. For example, when used as a paint tube for an automobile body, the outer diameter is 2 to 20 mm (particularly 3 to 16 mm). The inner diameter is about 1.0 to 15 mm (particularly 2 to 13 mm). If the difference between the outer diameter and the inner diameter (the thickness of the tube) is too large, the transparency decreases, so the difference between the outer diameter and the inner diameter is about 1 to 8 mm (particularly 1 to 6 mm). Tubes used in electrostatic coating machines and the like need to have high insulation characteristics such as dielectric breakdown voltage, so it is necessary to increase the tube wall thickness, but from the viewpoint of maintaining flexibility and transparency of the tube, the outer layer As the thermoplastic polyamide elastomer used in the above, it is preferable to select a low hardness grade having many elastomer components and excellent flexibility and transparency, particularly Shore D32 to Shore D42.

  The multilayer tube of the present invention can be obtained by a conventional method, for example, by multilayer extrusion molding (coextrusion molding) of the outer layer, the intermediate layer, the inner layer and, if necessary, the outermost layer. it can.

  Since the raw material used for the multilayer tube of the present invention does not contain a plasticizer, crazing due to tube hardening or thinning or hardening or embrittlement over time does not occur, and physical properties and performance such as flexibility do not change. .

  In the formation of the multilayer tube of the present invention, a multi-layer coextrusion molding machine (coextrusion molding machine) shown in FIG. 3 is required, but the raw material configuration shown in Table 1 (Nos. 1, 2, and 3 are thermoplastic polyamide elastomers). When unit 4 is molded with non-adhesive plastic nylon and unit 5 is an adhesive fluororesin), the temperature of the adapter from the cylinder is increased due to the low melting point of the polyamide elastomer located in units 1, 2, and 3. In order to improve the smoothness of the inner surface of the tube (maintaining excellent surface roughness), it is necessary to increase the temperature near the die on the outlet side. Therefore, it is impossible to lower the temperature near the die necessary for forming the tube surface into a satin-finished state, and the tube surface resin is led to the vacuum cooling water tank in a high temperature state, so that the crystallization of the tube surface resin is delayed and the surface itself is smooth (smooth) ) Tube is formed.

The raw material composition adopted for the above countermeasure is the composition shown in Table 2, and 20% of the thermoplastic polyetherester elastomer is blended in the first machine. The melting point of the main component thermoplastic polyamide elastomer (Pebax ^TM 55R53 manufactured by Arkema) is 167 ° C., whereas the melting point of the added thermoplastic ether ester elastomer (Hytrel ^TM 6377 manufactured by Toray DuPont) is 217 ° C. The temperature gradient from the cylinder in Unit 1 to the adapter can be set high. Since the decomposition temperature of the thermoplastic elastomer is 250 ° C., troubles such as thermal decomposition do not occur even if it is molded at the molding temperature shown in Table 2, and the molding temperature conditions near the die in Table 2 are kept low. Since the tube is guided to the vacuum cooling bath at a lower temperature, crystallization of the tube surface is accelerated, and a satin forming of the surface becomes possible.

  In addition to the above-described molding advantages, there is no problem in compatibility and bonding between the thermoplastic polyamide elastomer and the thermoplastic polyether ester elastomer because both soft segments are the same ether elastomer. Since the hard segment is heterogeneous between polyamide and polybutylene phthalate, it can be said that it is also effective to obtain an appropriate roughness (pear texture) on the tube surface.

  In order to describe the present invention more specifically and in detail, examples are shown below, but the present invention is not limited to these examples. Details of the components used in the examples and measurement methods for performance evaluation of the multilayer tubes obtained in the examples are shown below. In the examples, “parts” and “%” are based on mass unless otherwise specified.

[Contents of ingredients]
Inner layer (adhesive fluororesin):
Neoflon EFEP RP-5000 manufactured by Daikin Industries
Intermediate layer (adhesive polyamide):
Rilsan ^™ G KNO manufactured by Arkema
Outer layer (thermoplastic polyamide elastomer):
Arkema Pebax ^{TM (Pebax TM)} 55R53
Outermost layer 1 (thermoplastic polyamide elastomer + thermoplastic polyether ester elastomer):
Thermoplastic polyamide elastomer (manufactured by Arkema Pebax ^{TM (Pebax TM) 55R53):} 80 parts by weight thermoplastic polyetherester elastomer (manufactured by Du Pont-Toray Co., Ltd. Hytrel ^TM 6377): 20 parts by mass outermost 2 (thermoplastic polyamide elastomer + high Molecular antistatic agent):
Thermoplastic polyamide elastomer (manufactured by Arkema Pebax ^{TM (Pebax TM) 55R53):} 80 parts by weight polymeric antistatic agent (manufactured by Arkema Pebax ^{TM (Pebax TM) MV2080):} 20 parts by mass outermost layer 3 (thermoplastic polyamide elastomer + Polymer antistatic agent):
Thermoplastic polyamide elastomer (manufactured by Arkema Pebax ^{TM (Pebax TM) 55R53):} 85 parts by weight polymeric antistatic agent (manufactured by Arkema Pebax ^{TM (Pebax TM) MV2080):} 15 parts by weight

[Production example of compound constituting outermost layer 1]
Using a twin screw extruder (caliber: 46 mm, L / D = 46), 230 Aquema Pevax ^TM (Pebax ^TM ) 55R53 (80 parts by mass) and Toray DuPont Hytrel ^TM 6377 (20 parts by mass) are used. The mixture was melt-kneaded at 0 ° C. to obtain a pellet-shaped blend.

[Production example of compound constituting outermost layer 2]
Using a twin screw extruder (caliber 46 mm, L / D = 46), Arkema Pevax ^TM (Pebax ^™ ) 55R53 (80 parts by mass) and Arkema Pebax ^TM (Pebax ^TM ) MV2080 (20 parts by mass) Was melt-kneaded at 180 ° C. to obtain a pellet-shaped blend.

[Production example of the compound constituting the outermost layer 3]
Using a twin screw extruder (caliber 46 mm, L / D = 46), Arkema Pevax ^TM (Pebax ^TM ) 55R53 (85 parts by mass) and Arkema Pebax ^TM (Pebax ^TM ) MV 2080 (15 parts by mass) Was melt-kneaded at 180 ° C. to obtain a pellet-shaped blend.

(Example 1) Manufacture of a three-layer tube As an inner layer, NEOFRON EFEP RP-5000 (adhesive fluororesin) manufactured by Daikin Industries, Ltd. is used, and Rilsan ^™ G KNO (adhesive polyamide) manufactured by Arkema is used as an intermediate layer. as the outer layer, used by Arkema Pebax ^{TM (Pebax TM)} 55R53 (thermoplastic polyamide elastomer), in the manufacturing apparatus shown in FIG. 3, according to the molding conditions shown in Table 1, forming a three-layer tube of the structure shown in FIG. 1 did. The three-layer tube was manufactured in four types (outer diameter × inner diameter) of (4 mm × 2.5 mm), (6 mm × 4 mm), (8 mm × 6 mm), and (10 mm × 8 mm).

(Example 2) Production of four-layer tube As an inner layer, NEOFRON EFEP RP-5000 (adhesive fluororesin) manufactured by Daikin Industries, Ltd., and Rilsan ^™ G KNO (adhesive polyamide) manufactured by Arkema as an intermediate layer, as the outer layer, used by Arkema Pebax ^{TM (Pebax TM)} 55R53 (thermoplastic polyamide elastomer), as an outermost layer, using the formulation prepared in preparation example of formulations constituting an outermost layer 1 of FIG. 3 In the manufacturing apparatus shown, according to the molding conditions shown in Table 2, a four-layer tube having the structure shown in FIG. The four-layer tube was manufactured in four types (outer diameter × inner diameter) of (4 mm × 2.5 mm), (6 mm × 4 mm), (8 mm × 6 mm), and (10 mm × 8 mm).

(Example 3) Manufacture of antistatic type four-layer tube As an inner layer, NEOFRON EFEP RP-5000 (adhesive fluororesin) manufactured by Daikin Industries, Ltd. is used, and Rilsan ^™ G KNO (adhesive polyamide) manufactured by Arkema is used as an intermediate layer. the use, as the outer layer, used by Arkema Pebax ^{TM (Pebax TM)} 55R53 (thermoplastic polyamide elastomer), as an outermost layer, using the formulation prepared in preparation example of a formulation which constitutes the outermost layer 2 of, In the same manner as in Example 2, a four-layer tube having an antistatic layer as the outermost layer was molded. The four-layer tube was manufactured in five types (outer diameter × inner diameter) (4 mm × 2 mm), (4 mm × 2.5 mm), (6 mm × 4 mm), (8 mm × 6 mm), and (10 mm × 8 mm).

(Example 4) Manufacture of antistatic type four-layer tube The above-mentioned "preparation prepared in the manufacture example of the compound constituting the outermost layer 2" was prepared in the preparation example of the compound constituting the outermost layer 3. In the same manner as in Example 3 except that an object is used, the (outer diameter × inner diameter) is (4 mm × 2 mm), (4 mm × 2.5 mm), (6 mm × 4 mm), (8 mm × 6 mm), (10 mm × 8 mm). 5 types of four-layer tubes were manufactured.

(Comparative Example 1)
As the inner layer, NEOFRON EFEP RP-5000 (adhesive fluororesin) manufactured by Daikin Industries, Ltd. is used, and as the outer layer, Daiamide ZL1105 (nylon resin with adhesive plasticizer (polyamide 12)) manufactured by Daicel Eponic is used, Two types of two-layer tubes having (x inner diameter) of (6 mm x 4 mm) and (10 mm x 8 mm) were molded.

(Test Example 1) Surface slipperiness test As shown in FIG. 4, bundling with 6 test tubes around the upper and lower 2 test tubes, and using a binding band, the entire tube does not move. Fixed. At this time, a core rod was inserted in order to prevent the outer six test tubes bundled by the binding band from being deformed. This was attached to a tensile tester and pulled at a rate of 60 mm / min, and the force required for the central test tube to detach from the outer six tube bundles was measured. (The lower the value, the less the frictional resistance and the better the sliding performance)
Table 3 shows the test results for a tube having an outer diameter of 6 mm and an inner diameter of 4 mm.

  The four-layer tube of Example 2 with a satin finish on the surface of the tube has a detachment force of the central test tube reduced by 60% or more compared to the three-layer tube of Example 1, and the friction resistance is reduced by the finish of the finish. As a result, an effect of improving the sliding performance was confirmed. As for the two-layer tube of Comparative Example 1, since the plasticizer is blended, it is difficult to form a matte finish on the surface, but since the plasticizer itself is deposited on the tube surface, there is no effect on the matte finish. It is done.

(Test example 2) Water contact angle confirmation test on the inner surface of the tube (confirmation of liquid non-adhesion performance)
1. Test purpose Between the inner layer and the outer layer of the multilayer tube of the present invention, in order to strengthen the adhesion between the inner layer fluororesin and the outer layer thermoplastic polyamide elastomer, an adhesive polyamide (without plasticizer) is disposed as an intermediate layer. However, in addition to the improvement of the adhesive strength, it is considered effective for the smoothness of the inner surface of the fluororesin of the tube.

  That is, like the two-layer tube of Comparative Example 1, in the configuration of “fluorine resin + plasticizer-containing nylon resin two-layer tube”, there is a difference in the hardness between them and the resin molding temperature. The resin tends to be easily affected by the joint surface with the nylon resin of the outer layer, but when an adhesive polyamide is arranged as an intermediate layer like the multilayer tube of the present invention, the hardness between them and the resin molding temperature It is considered that the difference between the two is reduced, and the fluororesin in the inner layer is hardly affected by the joint surface with the adhesive polyamide.

  The smoothness of the inner surface of the tube can also be confirmed by measuring the surface roughness, but when considering the actual flow of liquid such as paint, the confirmation of “non-adhesion performance of liquid (repellency)” The determination is in line with actual use.

  “Non-adhesion performance of liquid (repellency, reverse wettability)” can be determined by dropping water on the sample surface and measuring its contact angle. Carried out.

2. Test tube (1) Four-layer tube of Example 2 (outer diameter 10 mm × inner diameter 8) [surface texture]
(2) Two-layer tube of Comparative Example 1 (outer diameter 10 mm × inner diameter 8)

3. Test Method Distilled water was dropped on the inner surface of the test tube cut in half in the axial direction, the angle θ ₁ shown in FIG. 5 was measured with a digital microscope, and 2θ ₁ was defined as the contact angle (θ / 2 method) ).

  Since the standard water contact angle confirmation test is performed for the purpose of confirming the performance of the surface smoothness (non-adhesion performance of the liquid) of the resin material itself, a plate (planar) of the resin material is used as the test sample. However, when a sample plate is formed by heating and press-molding a ring-shaped tube, the surface smoothness such as the inner surface roughness of the sample tube itself changes, and a substantial “liquid non-adhesion performance ( (Repellency) ”cannot be determined.

  Therefore, if the size is about “tube size: outer diameter 10 mm × inner diameter 8 mm” used in this test, the water contact angle can be confirmed and judged as a relative evaluation. The test was conducted.

4). Measurement Results Table 4 shows the results of measuring the contact angle for each test tube (n = 3).

5. Consideration of measurement results As is clear from the measurement results, the four-layer tube of Example 2 has a larger water contact angle and superior surface tension of water than the two-layer tube of Comparative Example 1, and as a result, It was confirmed that the “non-adhesion performance (repellency)” was excellent (representing the opposite meaning), the two-layer tube of Comparative Example 1 was more easily wetted than the four-layer tube of Example 2, and the liquid remained. Easy to do).

  In addition, the outer periphery of the four-layer tube of Example 2 is given a [surface satin finish] (improvement effect on the surface slip performance), but there is no influence on the tube inner surface due to the matte molding, and the quality of the tube inner surface smoothness It was also confirmed that it was maintained.

(Test example 3) Creep characteristic test for confirming guaranteed pressure resistance The resin used for the outer layer and the outermost layer of the four-layer tube of Example 2 is mainly composed of PA11 elastomer. The segment is PA11 (nylon 11) resin, and the soft segment is composed of a “polyether block polyamide copolymer” made of a polyether elastomer.

  Therefore, the hard segment PA11 has a structure in which the elastomer of the soft segment with rubber elasticity is connected in a chain, so that external pressure (internal pressure applied to the tube) can be applied rather than normal plasticized nylon. However, the amount of strain due to internal stress is small, and it is judged that the strain has excellent characteristics in terms of resilience after pressure release. As a support for this, for comparison with the four-layer tube of Example 2 and the two-layer tube of Comparative Example 1 having substantially the same level of characteristics (flexibility, hardness, strength, etc.) Was carried out.

2. Test tube (1) Four-layer tube of Example 2 (outer diameter 6 mm × inner diameter 4) [surface texture]
(2) Two-layer tube of Comparative Example 1 (outer diameter 6 mm × inner diameter 4)

3. Test method The guaranteed withstand pressure is 1.5 times the maximum operating pressure (rated pressure) of the tube, and this tube pressure is applied to the tube momentarily or for a short time to temporarily expand the outer diameter of the tube. Also, after the pressure is released (exhaust pressure), it refers to the pressure that can be restored to the original tube outer diameter.

(1) An internal pressure of 2.4 MPa (1.5 times the maximum operating pressure of 1.6 MPa) was applied to the tube and held for 5 minutes, and then the outer diameter of the tube was measured. Thereafter, the internal pressure was released, and the outer diameter of the tube immediately after opening was measured.
This test was performed a total of 6 times (total pressurization time: 30 minutes) using a single tube sample, and the tube outer diameter after 10 minutes was also measured after the final 6th pressurization release.

(2) An internal pressure of 2.4 MPa (1.5 times the maximum operating pressure of 1.6 MPa) was applied to the tube and held for 30 minutes, and then the outer diameter of the tube was measured. Thereafter, the internal pressure was released, and the outer diameter of the tube was measured immediately after opening and 10 minutes after releasing the pressure.

4). Test result (average value of n = 3)
The results are shown in Table 5.

5. Consideration of test results From the test results in Section 4, the four layers of Example 2 were used in both the intermittent pressurization / exhaust test of the test specification of (1) and the continuous pressurization test of the test specification of (2). It was confirmed that the tube had a smaller expansion coefficient (amount of strain) when the internal pressure was applied than the two-layer tube of Comparative Example 1, and was excellent in resilience after release of pressure.

  From this test result, even if an internal pressure higher than the maximum operating pressure is accidentally or momentarily applied to the tube due to an unexpected trouble, the outer layer is made of PA11 elastomer like the 4-layer tube of Example 2. It was confirmed that the constructed tube has higher safety.

(Test Example 4) Paint solvent entire surface immersion test Test Purpose The four-layer tube of Example 2 was developed mainly for the purpose of using paint for coating as a fluid, but a solvent for coating is also used as a fluid for cleaning the paint.

  For the solvent, the resistance of the fluororesin on the inner layer of the tube is required, but the nylon elastomer on the outer layer surface is also exposed to the solvent atmosphere, and sometimes the solvent itself scatters and adheres directly to the outer surface of the tube. Consideration of the risk of solvent penetration is also necessary.

  As a countermeasure to the above, in order to confirm the resistance to the main solvents (three types) used in the coating line, a coating solvent whole surface immersion test was conducted together with the two-layer tube of Comparative Example 1.

2. 2. Test tube and test solvent 2-1. Test tube (1) Four-layer tube of Example 2 (outer diameter 6 mm × inner diameter 4) [surface texture]
(2) Two-layer tube of Comparative Example 1 (outer diameter 6 mm × inner diameter 4)

2-2. Solvent for test A: Cleaning liquid for water-based paint “NK-01C thinner for water-based solvent” Cleaning stock solution: diluted to water = 12: 88 (weight ratio)
B: No cleaning liquid “PT-R (40) thinner” for clear paint
C: No cleaning dilution for two-component paint, etc.

3. Test Method The entire test tube was immersed in the test solvents A, B, and C for 1 week at room temperature, and then the tube was taken out and dried at room temperature. Thereafter, the outer diameter and weight of the tube were measured, and a tube single body tensile property test was conducted to confirm the change of the tube due to the influence of immersion. (Comparison with before immersion test) n = 3

(Details of tube tensile test)
As shown in FIG. 6, a test tube having a free length of 100 mm was attached to a tensile tester, and a tensile test was performed at a speed of 200 mm / min.

(Confirmation of tensile property test)
100% modulus (100% MD), tensile breaking strength, tensile breaking elongation.

4). Test Results Table 6 shows changes in the outer diameter and weight of the tube after the entire surface was immersed.

  Table 7 shows the results of the tube single body tensile property test (room temperature 26 ° C.) after the entire surface immersion.

5. Test results consideration (resistance to test solvent A)
The four-layer tube of Example 2 was determined to have no significant change in size and weight, and no problem in tensile properties.

  Although there was almost no change in the size and weight of the two-layer tube of Comparative Example 1, it was judged that the tensile break elongation was significantly reduced and the tube was cured by the solvent.

(Resistance to test solvent B)
The four-layer tube of Example 2 was confirmed to be slightly swollen due to solvent absorption in terms of size and weight, and the tensile properties were 100% MD, the strength at break was reduced, and the softening tendency of the tube was confirmed. It was not a problem.

  The two-layer tube of Comparative Example 1 had a large shrinkage of the outer inner diameter of the tube and a large weight change rate (decrease rate). Also in the tensile properties, 100% MD greatly increased and the elongation at break was greatly reduced, so that remarkable tube hardening was confirmed.

(Resistance to test solvent C)
The four-layer tube of Example 2 was confirmed to be slightly swollen due to solvent absorption in terms of size and weight, and the tensile properties were also reduced by 100% MD, breaking strength, and the tendency of the tube to soften was confirmed. It was not a problem that would cause problems in use.

  The two-layer tube of Comparative Example 1 was almost the same as the test result of the test solvent B, and remarkable thinning of the tube and the effect phenomenon were confirmed.

  From the above results, it was confirmed that the PA11 elastomer used in the outer layer of the four-layer tube of Example 2 was slightly absorbed and swollen with respect to the test solvents B and C. It can be judged that there is no problem at all in the case of exposure in a solvent atmosphere or adhesion due to scattering of a solvent that occurs rarely. Compared to the four-layer tube of Example 2, the two-layer tube of Comparative Example 1 was confirmed to be cured in any of the test solvents, especially for the test solvents B and C. Occurred. Since the two types of solvents are so-called cleaning agents for oil-based paints, it is determined that a phenomenon of bleeding the plasticizer (oil) blended in the nylon layer has occurred. Therefore, even under actual use conditions (solvent atmosphere and scattering), it becomes a factor that promotes plasticizer bleeding, and there is a risk of shortening the usable period (life).

(Test Example 5) Comparative test of tube inner surface roughness, minimum bending radius, and flexibility Test purpose The multi-layer tube of the present invention is mainly intended to be a clean tube that does not use a plasticizer, but it has not only cleanliness but also superiority in improving the tube inner surface roughness and maintaining flexibility. In order to verify this, the tube inner surface roughness measurement, the minimum bending radius, and the flexibility test were performed by comparing the four-layer tube of Example 2 and the two-layer tube of Comparative Example 1.

  Nylon with plasticizer is produced because the tube gradually hardens due to the bleeding of the plasticizer due to changes over time, so the flexibility changes depending on the elapsed time (period) after production, and an index value cannot be obtained. An initial characteristic confirmation test was performed using a sample having a short elapsed time later.

2. Test tube (1) Four-layer tube of Example 2 (outer diameter 6 mm × inner diameter 4) [surface texture]
(2) Two-layer tube of Comparative Example 1 (outer diameter 6 mm × inner diameter 4)

3. Test contents and results (1) Tube inner surface roughness measurement test: along the vertical direction (fluid flow direction) of the tube inner diameter side surface, using a precision roughness measuring instrument (Surfcom), the tube inner surface in the vertical direction The surface roughness of was measured. (Evaluation length: 0.8mm)
The results are shown in Table 8.

(2) Minimum bending radius measurement test: As shown in FIG. 7, after the tube was made into an annular shape, the tube was bent gradually, and the deformation rate (flatness) of the bending apex reached 10%. The diameter (R) is read, and 1/2 of the diameter is set as the minimum bending radius.

  The results are shown in Table 9.

(3) Flexibility test: As shown in FIG. 8, the test tube was set in a flexibility tester, deformed until the tube was broken, and the bending stress was measured for each bending radius. The tube length was 180 mm. (N = 3)
The results are shown in Table 10.

4). Test Result Discussion From the test results, it was confirmed that the four-layer tube of Example 2 was superior to the two-layer tube of Comparative Example 1 in all of the tube inner surface roughness, the minimum bending radius, and flexibility.

  In addition, regarding the test results, the PA11 elastomer used in the four-layer tube of Example 2 takes into account changes in data (hardness, etc.) due to the elapsed time (period) after production, like nylon with plasticizer. There is no need to do this, and it is judged that there is a great advantage in that a constant performance can always be obtained.

(Test Example 6) Helium leakage measurement test under high vacuum environment (confirmation of gas barrier performance)
1. Test purpose Tubes used for painted piping use cleaning solvent as a fluid, and if the solvent evaporates, there is a possibility that the tube will permeate and leak to the outside. Gas barrier performance is required. With the external environment of the tube kept at a high vacuum, a helium leak amount measurement test was performed on the four-layer tube of Example 2 and the two-layer tube of Comparative Example 1.

2. Test tube, etc. (1) Four-layer tube of Example 2 (outer diameter 6 mm × inner diameter 4) [surface texture]
(2) Two-layer tube of Comparative Example 1 (outer diameter 6 mm × inner diameter 4)
(3) Fitting: SUS inner diameter seal type tightening fitting (for high vacuum)

3. Test Method FIG. 9 shows a test apparatus for measuring the amount of helium leak using the vacuum vessel method.

  Prior to measuring the helium leak amount of each specimen, the cocks 1 and 2 were “closed”, the chamber was evacuated with the specimen installed in the vacuum chamber, and the background was measured. The cock 1 was opened, the inside of the specimen was evacuated, the cock 1 was closed, the cock 2 was opened, and helium gas was pressurized (0.1 MPa) into the specimen. Next, the chamber was evacuated and the amount of helium leakage was measured. The measurement of the amount of helium leakage is a value at which the amount of helium leakage is stable. (Measurement time: about 60 minutes)

4). Test Results FIG. 10 shows the relationship between the tube length of the four-layer tube of Example 2 and the two-layer tube of Comparative Example 1 and the helium leak rate (including the helium leak rate of the joint).

5. Test results consideration From the test results, the 4-layer tube of Example 2 was superior to the 2-layer tube of Comparative Example 1 in terms of gas barrier performance, albeit slightly.

  However, in consideration of long-term use, the plasticized nylon used in the two-layer tube of Comparative Example 1 is naturally considered to have a reduced gas barrier performance due to bleed out of a low molecular plasticizer. It is judged that the 4-layer tube of Example 2 of the PA11 elastomer type without any is superior from the viewpoint of maintaining the performance.

(Test Example 7) Antistatic performance of outermost layer of antistatic four-layer tube Each of the compositions constituting the outer layer of the three-layer tube of Example 1 and the outermost layer of the antistatic four-layer tube of Examples 3 and 4 Table 11 shows the surface resistivity and volume resistivity.
Test method: IEC 60093 test standard test sample plate: □ 100 mm × thickness 2 mm injection molded plate

  The antistatic grade raw material used in the antistatic type four-layer tube of Examples 3 and 4 has a low surface specific resistance and volume specific resistance in the measurement verification of the resistance value by the injection molding plate, and has sufficient antistatic performance. Have no static electricity.

1 Inner layer (adhesive fluororesin layer)
2 Intermediate layer (adhesive polyamide layer)
3 Outer layer (thermoplastic polyamide elastomer layer)
4 Outermost layer (layer consisting of thermoplastic polyamide elastomer and (thermoplastic polyetherester elastomer or polymer antistatic agent))

Claims (6)

A hollow tube composed of a plurality of layers in the thickness direction, wherein the plurality of layers are composed of an outermost layer composed of a thermoplastic polyamide elastomer and a thermoplastic polyether ester elastomer and a thermoplastic polyamide elastomer from the outside. A multi-layer tube comprising an outer layer, an intermediate layer made of an adhesive polyamide, and an inner layer made of an adhesive fluororesin , wherein the adhesive polyamide is an unplastic type polyamide 11 and an unplastic type polyamide 12 Selected from polyamide 6/12, plasticizer-blended polyamide 11 and plasticizer-blended polyamide 12, wherein the adhesive fluororesin is a homopolymer or copolymer having a tetrafluoroethylene unit and has a functional group at the terminal or side chain A multilayer tube made of resin . Thermoplastic polyether ester elastomer, a hard segment composed of polybutylene terephthalate, polyalkylene ether glycol according to claim 1, wherein the multilayer tube is a multi-block polymer soft segment consisting of terephthalic acid ester is bonded alternately. The multilayer tube according to claim 1 or 2 , wherein the outer surface of the outermost layer is formed in a satin finish. The multilayer polyamide according to any one of claims 1 to 3, wherein the thermoplastic polyamide elastomer is a polyamide block copolymer comprising a hard segment constituted by a polyamide component and a soft segment constituted by a polyalkylene ether glycol component. tube. The multilayer tube according to any one of claims 1 to 4 , which does not contain a plasticizer. The multilayer tube according to any one of claims 1 to 5 , which is a paint piping tube for painting, a beverage transport tube, a liquid food transport tube, a chemical transport tube or a clean room piping tube.

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