WO2017082310A1

WO2017082310A1 - Method for manufacturing tube and tube

Info

Publication number: WO2017082310A1
Application number: PCT/JP2016/083272
Authority: WO
Inventors: 将司清水; 章今田
Original assignee: ニッタ株式会社
Priority date: 2015-11-09
Filing date: 2016-11-09
Publication date: 2017-05-18
Also published as: TW201722683A

Abstract

Provided is a method for manufacturing a tube, the method comprising: a step of extrusion-molding a thermoplastic resin or a thermoplastic elastomer downward in a vertical direction, in a tube shape; a step of gradually cooling a tube 1 extruded downward in the vertical direction while suppressing heat radiation; and a step of winding the gradually-cooled tube 1 at a winding speed substantially the same as the extrusion speed of the tube 1.

Description

Tube manufacturing method and tube

The present invention relates to a method for producing a tube made of a thermoplastic resin or a thermoplastic elastomer and having a large elongation at break, and the tube.

In recent years, tubes using various thermoplastic resins and thermoplastic elastomers have been provided for industrial and medical purposes. For tube production, a method using an extrusion molding machine is generally used.

In extrusion molding, a sizing device is added to the front surface of the extrusion head of the extrusion molding machine in order to improve the appearance and outer diameter dimensional accuracy of the tube (for example, Patent Document 1). That is, as shown in FIG. 4, in a normal extruder, the tube 101 pushed out from the nozzle 100 is passed through a sizing device 104 including a holder 102 and a vacuum water tank 103. The holder 102 is provided with a sizing die 105.
Therefore, when the extruded tube is pulled by a take-up roll or the like, it is rubbed by the sizing die 105 and the resin is stretched inside and outside the tube 101, so that resin orientation occurs in the extrusion direction.

On the other hand, in the case of a tube for transporting fluid, for example, it is necessary to press-fit the tube into a pipe joint when connecting to equipment. Leading to a decline.

Patent Document 1 describes that after sizing after extrusion molding as described above, in order to correct orientation distortion, only the surface of the tube is heated and melted and then cooled and solidified, so-called annealing treatment is described. ing. Patent Document 1 shows that such an annealing process improves the elongation of the tube to about 320% (see FIGS. 2 and 3). However, considering the durability of the tube, higher tensile elongation and higher tensile strength are desired. Further, the molding method of Patent Document 1 is inferior in productivity because the number of steps such as annealing treatment increases.

Japanese Patent Laid-Open No. 57-210831

An object of the present invention is to provide a tube manufacturing method and a tube which are made of a thermoplastic resin or a thermoplastic elastomer and have improved tensile properties.

As a result of intensive studies to achieve the above-mentioned problems, the present inventors have completed the present invention. That is, the present invention has the following configuration.
(1) A step of extruding a thermoplastic resin or a thermoplastic elastomer vertically in a tube-like form, a step of gradually cooling the tube extruded downward in the vertical direction while suppressing heat dissipation, and a step of cooling Winding the tube at a take-up speed substantially equal to the tube extrusion speed.
(2) The method for producing a tube according to (1), wherein the tube is extruded while air is fed into the tube, and is gradually cooled while maintaining a predetermined diameter.
(3) The method for producing a tube according to (1) or (2), wherein the step of slow cooling is performed under conditions controlled so that the ambient temperature gradually decreases.
(4) The method for producing a tube according to any one of (1) to (3), wherein the thermoplastic resin is a polyamide resin, a polyurethane resin, or a polyester resin.
(5) The method for producing a tube according to any one of (1) to (3), wherein the thermoplastic elastomer is a polyamide elastomer, a polyurethane elastomer or a polyester elastomer.
(6) The method for producing a tube according to any one of (1) to (5), wherein the thermoplastic resin or thermoplastic elastomer contains a filler.
(7) The method for producing a tube according to (6), wherein the filler is a carbon nanotube.
(8) It consists of a polyamide resin or a polyamide-based elastomer, and the orientation obtained by the following formula from the peak intensity of each Raman spectrum in the axial direction and the circumferential direction of the tube measured with a Raman spectrometer is 2 or less. Characteristic tube.

However, the symbols in the formula are as follows.
A—P1: Peak intensity around 1440 cm ⁻¹ in the axial direction A—P2: Peak intensity around 1110 cm ⁻¹ in the axial direction B—P1: Peak intensity around 1440 cm ⁻¹ in the circumferential direction B—P2: 1110 cm in the circumferential direction ^-1 peak intensity (9) Made of polyurethane resin or polyurethane elastomer, the orientation obtained by the following formula from the peak intensity of each Raman spectrum in the axial direction and circumferential direction of the tube measured with a Raman spectrometer. A tube characterized by being 2 or less.

However, the symbols in the formula are as follows.
A-P1: the peak intensity at around 1180 cm ^-1 in the axial direction A-P2: the peak intensity at around 1610 cm ^-1 in the axial direction B-P1: the peak intensity at around 1180 cm ^-1 in the circumferential direction B-P2: 1610 cm in the circumferential direction ^-10 peak intensity (10) Made of polyester resin or polyester elastomer, the orientation obtained by the following formula from the peak intensity of each Raman spectrum in the axial direction and the circumferential direction of the tube measured with a Raman spectroscope. A tube characterized by being 2 or less.

However, the symbols in the formula are as follows.
AP: Peak intensity near 1727 cm ⁻¹ in the axial direction AP2: Peak intensity near 1616 cm ⁻¹ in the axial direction BP1: Peak intensity near 1727 cm ⁻¹ in the circumferential direction BP2: 1616 cm in the circumferential direction ^-1 peak intensity around (11) The tube according to any one of (8) to (10), containing a filler.
(12) The tube according to (11), wherein the filler is a carbon nanotube.
(13) an extruder that extrudes a thermoplastic resin in a vertically downward direction in a tubular form;
A heat-dissipating shielding cylinder that is installed below the nozzle provided downward of the extruder and that is gradually cooled by inserting a tube extruded from the nozzle,
A tube manufacturing apparatus comprising: a winding roll that winds the slowly cooled tube at a take-up speed substantially equal to the tube extrusion speed.

According to the method for manufacturing a tube of the present invention, by suppressing the heat dissipation of the extruded tube, the tube is solidified while maintaining a semi-molten state, so that the extrusion rate unevenness in the axial direction of the tube can be controlled.
That is, since the tube obtained by the above production method has a resin orientation of 2 or less, the molecular orientation of the polymer is low, thereby increasing the tensile elongation in the axial direction of the tube.
Specifically, the tube of the present invention has improved elongation at break in the axial direction. For this reason, even when stress acts on the resin tube at the time of tube expansion or when a strong tension is applied at the time of use, sufficient durability is ensured and it is possible to contribute to extending the life of the tube.
In the present invention, since it is not necessary to perform an annealing process to correct the orientation strain as in the prior art, there is no increase in the number of processes or a decrease in productivity.

It is explanatory drawing which shows the Raman spectrum measurement direction of the sample tube in this invention. It is a graph which shows an example of the Raman spectrum for calculating | requiring the orientation in this invention. It is explanatory drawing which shows the manufacturing apparatus of the tube which concerns on one Embodiment of this invention. It is a schematic sectional drawing which shows the normal extrusion molding machine provided with the sizing apparatus.

Hereinafter, the tube which concerns on embodiment of this invention is demonstrated in detail. The tube according to the embodiment of the present invention is made of a thermoplastic resin such as a polyamide-based resin, a polyurethane-based resin, or a polyester-based resin, or a thermoplastic elastomer such as a polyamide-based elastomer, a polyurethane-based elastomer, or a polyester-based elastomer. It is characterized by the orientation obtained by the following formula from the analysis by 2 being 2 or less.

The symbols in the formula are as follows.
A—P1: Peak intensity near the specific wavelength (I) in the axial direction A—P2: Peak intensity near the specific wavelength (II) in the axial direction B—P1: Peak intensity B—in the circumferential direction near the specific wavelength (I) P2: Peak intensity near a specific wavelength (II) in the circumferential direction

In the Raman spectrum measurement, the peak intensity is measured separately in the axial direction and the circumferential direction of the sample tube. For example, when the sample tube is installed in the Raman spectroscopic device, the axial direction (A direction) and the circumferential direction (B direction) of the tube shown in FIG. it can.
For each of the axial direction and the circumferential direction of the tube, a specific polarization component is detected using a polarizing lens to obtain a Raman spectrum. In this Raman spectrum, the peak (P1) near the specific wavelength (I) and the peak (P2) near the specific wavelength (II) are confirmed, and the respective peak intensities (peak heights) are obtained.

The specific wavelength (I) and the specific wavelength (II) vary depending on the resin type. In the following, A-P1, A-P2, B-P1 and B-P2 are shown for some resin types.
(I) polyamide resin or polyamide elastomer,
A—P1: Peak intensity around 1440 cm ⁻¹ in the axial direction A—P2: Peak intensity around 1110 cm ⁻¹ in the axial direction B—P1: Peak intensity around 1440 cm ⁻¹ in the circumferential direction B—P2: 1110 cm in the circumferential direction ^-1 vicinity of the peak intensity (ii) polyurethane resin or polyurethane elastomer a-P1: the peak intensity at around 1180 cm ^-1 in the axial direction a-P2: the peak intensity at around 1610 cm ^-1 in the axial direction B-P1: circumferential peak intensity near 1180 cm ^-1 in the B-P2: the peak intensity at around 1610 cm ^-1 in the circumferential direction (iii) a polyester resin or polyester-based elastomer a-P1: the peak intensity at around 1727 cm ^-1 in the axial direction a-P2: peak intensity near 1616cm ^-1 in the axial direction B-P1: circumferential direction Peak intensity near 1727 cm ^-1 in the B-P2: the peak intensity Figure 2 in the vicinity of 1616cm ^-1 in the circumferential direction shows the Raman spectrum of the polyamide-based resin or a polyamide-based elastomer.

Here, since the peak (P1) is derived from the C—H bond in the polymer compound, it is derived from the side chain of the polymer compound. On the other hand, the peak (P2) originates from the C—C bond, C═C bond, and the like in the polymer compound, and hence from the main chain of the polymer compound.

Therefore, when the orientation of the polymer compound is high, the ratio of the peak intensity indicated by P2 / P1 is large.
On the other hand, whether the orientation of the polymer compound is strongly applied in the A direction or the B direction can be determined by comparing P2 / P1 in each direction. Therefore, the closer the ratio of {(A-P2) / (A-P1)} / {(B-P2) / (B-P1)} to 1, the smaller the orientation, that is, the molecular orientation of the polymer It shows that they are not aligned.
Note that Raman spectroscopy is effective as an evaluation method for the orientation of crystalline polymers. For example, Michinori Kawano et al., Okayama Industrial Technology Center H27-17, “Evaluation of orientation of polypropylene with a laser Raman microscope”, < It is reported at http: //www.pref/okayama.jp/sangyo/kougi//riyo/report/pdf/2014/H27-17.pdf>. In this report, the relationship between the draw ratio of polypropylene and the Raman spectrum was investigated, and it was described that a large change was observed in the Raman spectrum due to stretching.

The orientation of the tube of the present invention determined from the above formula is 2 or less, preferably 1.6 or less. The orientation is preferably as close to 1 as possible. Since the orientation of the tube of the present invention in which the orientation is in the above range is suppressed in the axial direction, the tensile elongation in the axial direction becomes high.

Specifically, the tube of the present invention has a high elongation at break in the axial direction, as shown in Examples described later. The elongation at break varies depending on the material of the thermoplastic resin or thermoplastic elastomer used. For example, the polydodecanamide (polyamide 12) tube used in the examples has a elongation at break of 350% or more, particularly 400% or more. .
The elongation at break can be measured by a tensile tester. In measurement, a tube having a predetermined length is fixed to a tensile tester and a tensile test is performed.

Examples of the thermoplastic resin forming the tube of the present invention include, in addition to the above-described polyamide resin, polyurethane resin, and polyester resin, polyimide resin, polystyrene resin, polycarbonate resin, polyolefin resin, and acrylic resin. Resin, methacrylic resin, fluorine resin, silicone resin, polyacetal resin (polyoxymethylene), polyarylate resin, polyphenylene ether, polyphenylene sulfide, polysulfone, polyethersulfone, polyetheretherketone, vinyl chloride resin, polyvinyl resin Examples include, but are not limited to, resins. In addition, the thermoplastic resin may be used singly or in plural, and multicomponent systems such as copolymerization, addition, blending, and alloy may be used singly or in plural. More preferred are polyamide resins, polyurethane resins, and polyester resins.

Specific examples of the polyamide-based resin include polyamide 11, polyamide 12, polyamide 6, polyamide 66, polyamide 610, polyamide 612, polyamide 666, polyamide 46, polyamide 10T, polyamide 6T, aramid resin (fully aromatic polyamide), and the like. It is done. Specific examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Specific examples of the polyolefin resin include polyethylene and polypropylene.

Examples of the thermoplastic elastomer (TPE) include, but are not limited to, the above-described polyamide-based thermoplastic elastomer, polyurethane-based thermoplastic elastomer, and polyester-based thermoplastic elastomer. The thermoplastic elastomer is a polymer composed of a hard phase (hard segment) and a soft phase (soft segment), and exhibits properties as rubber at room temperature, but exhibits thermoplasticity at high temperature.

Examples of the polyamide-based elastomer include a hard segment made of polyamide and a block copolymer with a soft segment.

The polyurethane-based thermoplastic elastomer is an elastic body obtained by a reaction between a polyol and an isocyanate, and a known thermoplastic polyurethane (TPU) can be used. A thermoplastic polyurethane can be used individually by 1 type or in combination of 2 or more types. The thermoplastic polyurethane is usually obtained by reacting polyisocyanate, a long-chain polyol, a chain extender, and, if necessary, another isocyanate-reactive compound.
The polyisocyanate is not particularly limited as long as it is a compound having at least two isocyanate groups in the molecule. Examples of the polyisocyanate include aliphatic polyisocyanate, alicyclic polyisocyanate, aromatic polyisocyanate, and araliphatic polyisocyanate. Polyisocyanate can be used individually or in combination of 2 or more types.

Examples of the aliphatic polyisocyanate include 1,3-trimethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,2-propylene diisocyanate, 1, 2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2-methyl-1,5-pentamethylene diisocyanate, 3-methyl-1,5-pentamethylene diisocyanate, 2,4,4- And aliphatic diisocyanates such as trimethyl-1,6-hexamethylene diisocyanate and 2,2,4-trimethyl-1,6-hexamethylene diisocyanate.

Examples of the alicyclic polyisocyanate include 1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate). 4,4-Methylenebis (cyclohexyl isocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, 1, 4-bis (isocyanate methyl) Examples include alicyclic diisocyanates such as cyclohexane and norbornane diisocyanate.

Examples of aromatic polyisocyanates include m-phenylene diisocyanate, p-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthylene-1,4-diisocyanate, and naphthylene-1,5-diisoisocyanate. 4,4 · -diphenyl diisocyanate, 4,4 · -diphenylmethane diisocyanate, 2,4 · -diphenylmethane diisocyanate, 2,2 · -diphenylmethane diisocyanate, 4,4 · -diphenyl ether diisocyanate, 2,2 · -di Aromatic diisocyanates such as phenylpropane-4,4-diisocyanate, 3,3-dimethyldimethylphenyl-4,4-diisocyanate, 4,4-diphenylpropane diisocyanate And so on.

Examples of the araliphatic polyisocyanate include 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, ω, ω · -diisocyanate-1,4-diethylbenzene, 1,3-bis (1-isocyanate- And araliphatic diisocyanates such as 1-methylethyl) benzene, 1,4-bis (1-isocyanate-1-methylethyl) benzene, 1,3-bis (α, α-dimethylisocyanatomethyl) benzene, and the like.
Examples of polyisocyanates include 1,6-hexamethylene diisocyanate, 4,4-methylene bis (cyclohexyl isocyanate), 1,3-bis (isocyanate methyl) cyclohexane, 1,4-bis (isocyanate methyl) cyclohexane, isophorone diisocyanate, 2 , 4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4-diphenylmethane diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, norbornane diisocyanate, 1, 3-bis (α, α-dimethylisocyanatomethyl) benzene can be preferably used.

As the polyisocyanate, the exemplified aliphatic polyisocyanate, alicyclic polyisocyanate, aromatic polyisocyanate, dimer or trimer by araliphatic polyisocyanate, reaction product or polymer (for example, diphenylmethane diisocyanate). Dimers and trimers of, reaction products of trimethylolpropane and tolylene diisocyanate, reaction products of trimethylolpropane and hexamethylene diisocyanate, polymethylene polyphenyl isocyanate, polyether polyisocyanate, polyester polyisocyanate, etc. ) Etc. can also be used.

Examples of the long-chain polyol include polyether polyol, polyester polyol, polycarbonate polyol, polyolefin polyol, and polyacryl polyol.

Examples of the polyether polyol include polyalkylene ether glycols such as polyethylene ether glycol, polypropylene ether glycol, and polytetramethylene ether glycol (PTMG), and a plurality of alkylene oxides as monomer components such as an ethylene oxide-propylene oxide copolymer. And (alkylene oxide-other alkylene oxide) copolymers containing.

Examples of the polyester polyol include a condensation polymer of a polyhydric alcohol and a polyvalent carboxylic acid; a ring-opening polymer of a cyclic ester (lactone); a reaction by three kinds of components: a polyhydric alcohol, a polyvalent carboxylic acid, and a cyclic ester. Things can be used. In the condensation polymer of polyhydric alcohol and polycarboxylic acid, the polyhydric alcohol includes, for example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,3-butanediol, , 4-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2,4- Diethyl-1,5-pentanediol, 1,9-nonanediol, 1,10-decanediol, glycerin, trimethylolpropane, trimethylolethane, cyclohexanediols (such as 1,4-cyclohexanediol), cyclohexanedimethanols (1,4-cyclohex Etc. Nji methanol), bisphenols (bisphenol A, etc.), such as sugar alcohols (such as xylitol or sorbitol) can be used. On the other hand, examples of polyvalent carboxylic acids include aliphatic dicarboxylic acids such as malonic acid, maleic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid; 1,4-cyclohexane Examples thereof include alicyclic dicarboxylic acids such as dicarboxylic acids; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, paraphenylene dicarboxylic acid and trimellitic acid.

In the ring-opening polymer of cyclic ester, examples of the cyclic ester include propiolactone, β-methyl-δ-valerolactone, and ε-caprolactone. In the reaction product of the three types of components, those exemplified above can be used as the polyhydric alcohol, polycarboxylic acid, and cyclic ester.

Examples of the polycarbonate polyol include a reaction product of a polyhydric alcohol and phosgene, chloroformate, dialkyl carbonate or diaryl carbonate; a ring-opening polymer of a cyclic carbonate (such as alkylene carbonate). Specifically, in the reaction product of a polyhydric alcohol and phosgene, the polyhydric alcohol includes the polyhydric alcohols exemplified above (for example, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol). Neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, etc.) can be used. In the ring-opening polymer of cyclic carbonate, examples of the alkylene carbonate include ethylene carbonate, trimethylene carbonate, tetramethylene carbonate, hexamethylene carbonate, and the like. In addition, the polycarbonate polyol should just be a compound which has a carbonate bond in a molecule | numerator, and the terminal is a hydroxyl group, and may have an ester bond with a carbonate bond. Representative examples of polycarbonate polyols include polyhexamethylene carbonate diol, diol obtained by ring-opening addition polymerization of lactone to polyhexamethylene carbonate diol, and co-condensate of polyhexamethylene carbonate diol with polyester diol or polyether diol. Etc.

The polyolefin polyol is a polyol having an olefin as a component of the skeleton (or main chain) of the polymer or copolymer and having at least two hydroxyl groups in the molecule (particularly at the terminal). The olefin may be an olefin having a carbon-carbon double bond at the terminal (for example, an α-olefin such as ethylene or propylene), or an olefin having a carbon-carbon double bond at a position other than the terminal. (For example, isobutene and the like) and diene (for example, butadiene, isoprene and the like) may be used. Representative examples of polyolefin polyols include butadiene homopolymers, isoprene homopolymers, butadiene-styrene copolymers, butadiene-isoprene copolymers, butadiene-acrylonitrile copolymers, butadiene-2-ethylhexyl acrylate copolymers, butadiene-n-octadecyl acrylate copolymers, and the like. Or the thing which modified the terminal of an isoprene-type polymer into a hydroxyl group is mentioned.
The polyacrylic polyol is a polyol having (meth) acrylate as a component of the polymer (or copolymer) skeleton (or main chain) and having at least two hydroxyl groups in the molecule (particularly at the terminal). As the (meth) acrylate, (meth) acrylic acid alkyl ester [for example, (meth) acrylic acid C1-20 alkyl ester, etc.] is preferably used. Also, for the polyol, any material other than those listed here can be used.

As the chain extender, a chain extender usually used in the production of thermoplastic polyurethane can be used, and the kind thereof is not particularly limited, but a low molecular weight polyol, polyamine or the like can be used. A chain extender can be used individually or in combination of 2 or more types.
Representative examples of chain extenders include ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,2 -Polyols such as pentanediol, 2,3-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol (Especially diols); polyamines (particularly diamines) such as hexamethylenediamine, 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, 4,4′-methylenebis-2-chloroaniline, and the like.

A commercially available product can be used as the thermoplastic polyurethane. Examples of commercially available products include adipate TPU having a hardness of 80, adipate TPU having a hardness of 90, a caprolactone TPU having a hardness of 90, a PTMG TPU having a hardness of 92, an adipate TPU having a hardness of 92, and the like.
These thermoplastic resins may be used alone, or two or more of them may be used in combination as long as the effects thereof are not impaired.

Polyester resin is obtained by polycondensation of polyvalent carboxylic acid and polyalcohol. Examples of the polyvalent carboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid. Examples of the polyalcohol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like.

Specific examples of the polyester-based resin include polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, and the like.
The polyester elastomer can be produced by transesterification or polycondensation reaction using dimethyl terephthalate, 1,4-butanediol, and poly (oxytetramethylene) glycol as raw materials.

In the thermoplastic resin and the thermoplastic elastomer, additives such as glass fibers and carbon nanotubes (CNT) may be added as a reinforcing material depending on the use, so long as the effect is not impaired. Not limited. By adding a reinforcing material to the thermoplastic resin, it is possible to increase the strength without impairing the tensile properties of the resulting tube, i.e., maintaining the elongation at break, thereby reducing the wall thickness and bending the tube. Etc. becomes easier.
The additive is usually added in a proportion of 30% by mass or less, preferably 10% by mass or less, based on the total amount of the tube. As the carbon nanotube, any of a single wall, a double wall, and a multilayer can be used.

Next, a method for manufacturing the tube of the present invention will be described. As described above, in the present invention, in order to give a high elongation at break to the tube, the orientation represented by the above formula is set as low as 2 or less. In order to obtain such a tube of the present invention, it is necessary to perform extrusion molding so that molecular orientation is not applied. For this purpose, it is important that the tube is solidified gradually without being rubbed due to sizing or a pulling force due to winding, or the like without being rapidly cooled.

To extrude the tube without applying stress, it is preferable to extrude the tube vertically downward from the tip nozzle of the extruder. In this case, since the tube tends to stretch due to its own weight at the time of dropping, the orientation is suppressed by gradually solidifying while feeding air into the tube so as to have a predetermined diameter.

In order to gradually solidify the extruded tube, it is important to control the ambient temperature. That is, when the solidification of the tube is delayed because the temperature is too high, the tube is stretched by its own weight, and a tube having a predetermined diameter or thickness cannot be obtained. On the other hand, when the temperature is low, the tube solidifies rapidly, so that the difference between the solidified portion and the melted portion becomes large, and the influence of its own weight and internal pressure concentrates on the melted portion immediately after coming out from the tip nozzle. As a result, it extends partially, leading to variations in dimensions and wall thickness.
Therefore, it is preferable to control the ambient temperature to gradually decrease so that no orientation is applied between the time when the tube is extruded and the time when the tube is solidified.

Hereinafter, an example of the manufacturing method of the tube of this invention is demonstrated based on FIG. In the extrusion molding machine 10 shown in FIG. 3, a screw 13 is provided in a cylinder 12 provided with a hopper 11, and a die 14 having a nozzle 15 is provided at the tip of the screw 13. The tube 1 pushed out vertically from the base 15 a of the nozzle 15 is wound on the outer peripheral surface of the winding roll 17. An outer diameter measuring device 18 is installed on the upstream side of the winding roll 17.
The extrusion molding machine 10 is not particularly limited, and may be a commercially available extrusion molding machine. The extrusion direction is not particularly limited as long as orientation is not applied, and may be, for example, a horizontal direction.

A long heat radiation shielding cylinder 19 is provided on the base 15 a of the nozzle 15. This heat radiation shielding cylinder 19 suppresses heat radiation of the tube 1 pushed out from the base 15a, and performs temperature control until the tube 1 is solidified. That is, the heat radiation shielding cylinder 19 has a function of imparting appropriate hardness (strength) by gradually solidifying the tube 1 while maintaining the semi-molten state without being influenced by the outside air temperature. Therefore, as long as this function is exhibited, the material of the heat shielding cylinder 19 is not particularly limited, and metal, plastic, paper, or the like can be used. In addition, examples of the shape include a circle, an ellipse, and a polygon. In consideration of the function, a circle is preferable. For example, when discharging the tube 1 downward in the vertical direction, it has a length necessary for solidifying the molten resin while keeping the temperature, and is preferably about 200 mm to 1 m, for example. Moreover, it is preferable to adjust the length of the cylinder in accordance with the discharge speed of the molten resin. If necessary, the heat radiation shielding cylinder 19 may have a temperature control function.
Moreover, you may control the temperature of the passage route of the tube 1 extruded as mentioned above.

The temperature of the cylinder 12 and the die 14 is set in advance according to the melting temperature of the thermoplastic resin to be charged. In this state, the produced pellet 3 is put into a hopper 11 of an extrusion molding machine 10 and poured into a cylinder 12. The resin of the pellet 3 that has flowed into the cylinder 12 is melted in the cylinder 12 to become a molten resin 2. The molten resin 2 is discharged in the direction of the die 14 by the rotation of the screw 13.

Next, the molten resin 2 is pushed out by the flow path in the die 14 and pushed out to the nozzle 15. A nozzle 15a for molding the tube is attached to the nozzle 15, and the tube 1 is manufactured by discharging from the nozzle 15a. Here, the nozzle 15 is not provided with a sizing process. Therefore, the tube 1 is discharged according to the discharge amount of the resin and passes through the heat radiation shielding cylinder 19. As the tube 1 passes through the heat radiation shielding cylinder 19, the tube 1 is solidified while being kept warm.

Next, the tube 1 is wound around the pulley 16, passes through the outer diameter measuring device 18, and is wound around the winding roll 17. A driving force is applied to the pulley 16 by a motor or the like, and a pulling force is applied to the discharged tube 1. The take-up speed at this time is set according to the discharge amount discharged from the die 14, and the take-up speed and the discharge speed are set to be substantially equal. *

Since the tube obtained by the above embodiment is as thin as 0.1 to 1.0 mm, it is important to stabilize the discharge amount and eliminate external force. As shown in FIG. 3, in this embodiment, the tube 1 is extruded downward in the vertical direction, and is pushed out while feeding air into the tube. Thereby, since the predetermined internal pressure is applied to the tube 1, the tube 1 is gradually cooled while maintaining a predetermined diameter, and deformation of the tube 1 in the radial direction can be prevented. In addition, it is preferable to prevent stress from acting in the axial direction of the molded tube 1 by setting the take-up speed according to the discharge amount. Furthermore, since sizing is not performed during resin extrusion, the orientation of the resin in the direction of the extrusion axis can be suppressed while maintaining the molding speed.

The tube 1 pushed out from the nozzle 15 is solidified while the resin is maintained in a semi-molten state in the process of passing through the heat radiation shielding cylinder 19. Thus, since the extruded tube 1 is gradually solidified in the heat radiation shielding cylinder 19, molding shrinkage can be reduced, and disturbance due to outside air or the like can be eliminated. Moreover, the orientation of the resin can be suppressed by solidifying while maintaining a semi-molten state.
Further, since the resin is gradually solidified, there is an advantage that a tube with high dimensional accuracy with little variation in the outer diameter can be obtained. It is considered that the outer diameter of the tube 1 is stable because an excessive stress is not applied to the resin by controlling the pulling force while the resin is maintained in a semi-molten state.

Hereinafter, the present invention will be described more specifically with reference to examples. In addition, this invention is not limited only to these Examples.

Example 1
A commercially available pellet of polydodecanamide (nylon 12) was used as the thermoplastic resin, and this was put into an extrusion molding machine 10 shown in FIG. 3 to produce a tube 1 having an outer diameter of 1 mm and an inner diameter of 0.8 mm.
Here, as the heat radiation shielding cylinder 19, an iron cylinder having an outer diameter of 30 mm, an inner diameter of 27 mm, and a length of 1 m was used. The heat radiation shielding cylinder 19 was attached to the base 15 a of the nozzle 15, the tube 1 was pushed out from the base 15 a, and a predetermined amount of air was injected into the tube 1 while passing through the heat radiation shielding cylinder 19 and solidified. At this time, the extrusion speed was set to 20 m / min. The extrusion speed shown here refers to the speed of the resin discharged from the extruder.
At this time, a thermocouple was inserted into the cylinder through through holes provided in the heat radiation shielding cylinder 19 at predetermined intervals, and the temperature in the cylinder was measured. The results are shown in Table 1.

It can be seen from Table 1 that the tube gradually cools and solidifies in the process of passing through the heat radiation shielding cylinder 19 because the temperature of the end of the heat radiation shielding cylinder 19 is lowered to a temperature close to room temperature.

(Comparative Example 1)
A commercially available pellet of polydodecanamide (polyamide 12) was used as the thermoplastic resin, and a tube having an outer diameter of 1 mm was produced by an extruder equipped with a sizing device 104 as shown in FIG.

(Comparative Example 2)
As a thermoplastic resin, a commercially available pellet of polyamide 12 is extruded in the same manner as in Example 1 except that it does not have the heat-shielding cylinder 19, and the outer diameter is 1 mm. A tube was prepared.

<Evaluation test>
(Elongation at break)
A tube of a predetermined length obtained by an extrusion molding machine is fixed to a tensile tester (AGS-5KNX manufactured by Shimadzu Corporation), a tensile test is performed at a tensile speed of 100 mm / min, and the elongation at break in the axial direction of the resin tube is measured. did. The results are shown in Table 1.
(Orientation)
The tube obtained by the extrusion molding machine was attached to a Raman spectroscope (NRS-3100 manufactured by Jasco). A laser having a wavelength of 532 nm was used as the light source.
In installing the sample tube in the apparatus, the tube was first installed in a predetermined direction so that the peak intensity in the axial direction could be measured. Then, the peak intensity (A-P1) near 1440 cm ⁻¹ and the peak intensity (A-P2) near 1110 cm ⁻¹ in the axial direction were measured.
Next, the installation direction of the tube in the apparatus is changed (that is, changed to the direction orthogonal to the installation direction in the axial direction), and the peak intensity (B-P1) near 1440 cm ⁻¹ in the circumferential direction and 1110 cm ^{− is changed.} The peak intensity around ¹ (BP2) was measured.
Thereafter, the orientation was determined by the above formula. The results are shown in Table 2. The closer the orientation is to 1, the more uniform force is applied to the molded product, and the smaller the orientation, in other words, the molecular orientation of the polymer is not uniform.

From the results shown in Table 2, it can be seen that the tube obtained according to the embodiment of the present invention has improved elongation at break in the axial direction of the tube as compared with the case of using another extrusion molding machine. Moreover, it turns out that orientation is related as a factor which this breaking elongation improved. If the orientation during extrusion molding is close to 1, that is, there is no orientation in the extrusion direction and circumferential direction of the tube, a high elongation at break can be obtained.

Example 2
(Polyamide elastomer tube)
As the thermoplastic elastomer, commercially available polyamide elastomer pellets (PEBAX (registered trademark) manufactured by Arkema Co., Ltd.) were used, and this was put into an extrusion molding machine 10 shown in FIG. 3, and the outer diameter was 1 mm and the inner diameter was 0.8 mm. Tube 1 was produced.
Here, as the heat radiation shielding cylinder 19, the same iron cylinder as in Example 1 was used. The heat radiation shielding cylinder 19 is attached to the base 15a of the nozzle 15, the tube 1 is extruded from the base 15a, and a predetermined amount of air is injected into the tube 1 while passing through the heat radiation shielding cylinder 19 in the same manner as in the first embodiment. The solution was gradually cooled and solidified. At this time, the extrusion speed was set to 20 m / min.

Example 3
(Polyurethane elastomer tube)
As a thermoplastic elastomer, commercially available polyurethane elastomer pellets (Milactolan (registered trademark) manufactured by Nippon Milactolan Co., Ltd.) are used, and this is put into an extrusion molding machine 10 shown in FIG. 3, and has an outer diameter of 1 mm and an inner diameter of 0.8 mm. The tube 1 was prepared.
Here, as the heat radiation shielding cylinder 19, the same iron cylinder as in Example 1 was used. The heat radiation shielding cylinder 19 is attached to the base 15a of the nozzle 15, the tube 1 is extruded from the base 15a, and a predetermined amount of air is injected into the tube 1 while passing through the heat radiation shielding cylinder 19 in the same manner as in the first embodiment. The solution was gradually cooled and solidified. At this time, the extrusion speed was set to 20 m / min.

Example 4
(Polyester elastomer tube)
As the thermoplastic elastomer, a commercially available polyester elastomer (Primalloy (registered trademark) manufactured by Mitsubishi Chemical Corporation) is used, and this is put into an extrusion molding machine 10 shown in FIG. 3, and has an outer diameter of 1 mm and an inner diameter of 0.8 mm. The tube 1 was prepared.
Here, as the heat radiation shielding cylinder 19, the same iron cylinder as in Example 1 was used. The heat radiation shielding cylinder 19 is attached to the base 15a of the nozzle 15, the tube 1 is extruded from the base 15a, and a predetermined amount of air is injected into the tube 1 while passing through the heat radiation shielding cylinder 19 in the same manner as in the first embodiment. The solution was gradually cooled and solidified. At this time, the extrusion speed was set to 20 m / min.

The tubes obtained in Examples 2 to 4 were examined for elongation at break and orientation in the same manner as in Example 1. The results are shown in Table 3. Table 3 also shows the wavelengths indicating the peak intensities in the axial and circumferential directions of the tube.

(Note) In P1 and P2, the upper stage indicates the axial direction of the tube, and the lower stage indicates the circumferential direction.
PAE: Polyamide elastomer, TPU: Polyurethane elastomer, TPEE: Polyester elastomer

From the results shown in Table 3, it can be seen that also in the thermoplastic elastomer, the orientation at the time of extrusion molding can approach 1 as in the thermoplastic resin, so that the elongation at break in the axial direction of the tube is improved. .

Example 5
(Polyamide tube with carbon nanotubes added)
A tube was produced in the same manner as in Example 1 except that carbon nanotubes manufactured by Nanocyl Co. were added to a commercial pellet of polydodecanamide (nylon 12) at a ratio of 3.5% by mass with respect to the total amount. .
The tensile yield stress and breaking elongation of the obtained tube were measured. For comparison, the tensile yield stress and elongation at break of the tube obtained in Example 1 were measured in the same manner.
The tensile yield stress was determined by the tensile yield stress described in JIS K7161 (Plastic-Test method for tensile properties). The elongation at break was determined in the same manner as in Example 1. The results are shown in Table 4.

As shown in Table 4, the tensile yield stress is improved by adding carbon nanotubes. Therefore, the tube pressure resistance related to the tensile yield stress is expected to be improved by 30%, and the breaking pressure of the tube is improved.

DESCRIPTION OF SYMBOLS 1 Tube 2 Molten resin 3 Pellet 11 Hopper 12 Cylinder 13 Screw 14 Die 15 Nozzle 15a Base 16 Pulley 17 Winding roll 18 Outer diameter measuring device 19 Radiation shielding cylinder

Claims

A process of extruding a thermoplastic resin or thermoplastic elastomer vertically downward in a tubular form;
A step of slowly cooling the tube extruded downward in the vertical direction while suppressing heat radiation;
A step of winding the slowly cooled tube at a take-up speed substantially equal to the extrusion speed of the tube.
2. The method for producing a tube according to claim 1, wherein the tube is extruded while air is fed into the tube, and is slowly cooled while maintaining a predetermined diameter.
The method for producing a tube according to claim 1 or 2, wherein the slow cooling step is performed under conditions controlled so that the ambient temperature gradually decreases.
The method for producing a tube according to any one of claims 1 to 3, wherein the thermoplastic resin is a polyamide resin, a polyurethane resin or a polyester resin.
The method for producing a tube according to any one of claims 1 to 3, wherein the thermoplastic elastomer is a polyamide-based elastomer, a polyurethane-based elastomer, or a polyester-based elastomer.
The method for producing a tube according to any one of claims 1 to 5, wherein the thermoplastic resin or thermoplastic elastomer contains a filler.
The method for producing a tube according to claim 6, wherein the filler is a carbon nanotube.
It consists of a polyamide resin or a polyamide-based elastomer, and the orientation obtained by the following formula from the peak intensity of each Raman spectrum in the axial direction and the circumferential direction of the tube measured with a Raman spectrometer is 2 or less. tube.

However, the symbols in the formula are as follows.
A—P1: Peak intensity around 1440 cm −1 in the axial direction A—P2: Peak intensity around 1110 cm −1 in the axial direction B—P1: Peak intensity around 1440 cm −1 in the circumferential direction B—P2: 1110 cm in the circumferential direction -1 peak intensity
It is made of polyurethane resin or polyurethane elastomer, and the orientation obtained by the following formula from the peak intensity of each Raman spectrum in the axial direction and the circumferential direction of the tube measured with a Raman spectrometer is 2 or less. Tube.

However, the symbols in the formula are as follows.
A-P1: the peak intensity at around 1180 cm -1 in the axial direction A-P2: the peak intensity at around 1610 cm -1 in the axial direction B-P1: the peak intensity at around 1180 cm -1 in the circumferential direction B-P2: 1610 cm in the circumferential direction -1 peak intensity
It consists of a polyester-based resin or a polyester-based elastomer, and the orientation obtained by the following formula from the peak intensity of each Raman spectrum in the axial direction and circumferential direction of the tube measured with a Raman spectroscope is 2 or less, Tube.

However, the symbols in the formula are as follows.
AP: Peak intensity near 1727 cm −1 in the axial direction AP2: Peak intensity near 1616 cm −1 in the axial direction BP1: Peak intensity near 1727 cm −1 in the circumferential direction BP2: 1616 cm in the circumferential direction -1 peak intensity
The tube according to any one of claims 8 to 10, containing a filler.
The tube according to claim 11, wherein the filler is a carbon nanotube.
An extruder for extruding a thermoplastic resin in a vertically downward direction in a tubular form;
A heat-dissipating shielding cylinder that is installed below the nozzle provided downward of the extruder and that is gradually cooled by inserting a tube extruded from the nozzle,
A tube manufacturing apparatus comprising: a winding roll that winds the slowly cooled tube at a take-up speed substantially equal to the tube extrusion speed.