JP6910821B2 - Protective tubes, protective materials and wire harnesses - Google Patents

Description

The present invention relates to a technique of a protective tube, a protective material, and a wire harness that protects a bundle of electric wires composed of a plurality of electric wires.

As a technique for protecting the electric wire bundle, there are a shrinkable tube, a vinyl tube, and the like that cover the outer circumference of the electric wire bundle to protect the electric wire from the edge of an external interfering material.

Shrinkable tubes and vinyl tubes are widely used for various purposes such as bundling electric wires, protecting the ends of electric wires and connecting parts of electric wires, and insulating. A method for producing a shrinkable tube is disclosed in, for example, Patent Document 1. Further, the use of the vinyl tube is disclosed in, for example, Patent Document 2.

However, although the conventional shrinkable tube and vinyl tube are excellent in coating performance, they have a drawback that they can be used only in advance because they are tubular. For this reason, when it is desired to cover a bundle of electric wires with a shrinkable tube or a vinyl tube, it is necessary to pass the electric wires one by one through the shrinkable tube or the vinyl tube and then attach the connector, which is very troublesome. In addition, there is a problem that it cannot be used for a covering object that cannot be preempted, and the usable range is limited.

Therefore, a tube structure has been proposed so that an electric wire can be passed through (Patent Documents 3 and 4). However, since polypropylene, amide resin, etc. exemplified in Patent Document 3 are materials having a high elastic modulus, it is difficult to bend or twist them when they have a tube structure, and long articles such as electric wire bundles can be used. Movement is restricted when covered. Further, in the so-called corrugated tube in which peaks and valleys are alternately provided in the axial direction as in Patent Document 4, it is possible to bend a bundle of electric wires even if a material having a high elastic modulus is used. It cannot be moved freely like a shrinkable tube or a vinyl tube because there is a risk that the mountain parts will interfere with each other or the electric wire will be exposed by opening from the side to a large curve.

Japanese Unexamined Patent Publication No. 11-277626 Japanese Unexamined Patent Publication No. 11-150829 Japanese Unexamined Patent Publication No. 2016-127773 Japanese Unexamined Patent Publication No. 2004-321948

In view of the above circumstances, the present invention provides a protective tube, a protective material and a wire harness which can be used without passing a wire bundle in advance and have excellent flexibility in addition to good protective performance.

That is, the present invention is as follows.
(1) A protective tube for storing a long article in which a sheet made of a thermoplastic resin is wound in the circumferential direction, and the inner end and the outer end in the circumferential direction are overlapped with each other in the radial direction. A protective tube having a shape and a structure capable of accommodating a long article inside the inner end by opening the outer end, and having a 100% tensile modulus of the sheet of 50 MPa or less.
(2) The protective tube according to (1), wherein the heat shrinkage rate of the sheet after heating at 120 ° C. for 1 hour is 20% or less.
(3) The protective tube according to (1) or (2), wherein the embrittlement temperature of the sheet is −20 ° C. or lower.
(4) The protective tube according to any one of (1) to (3), wherein the minimum wall thickness of the tube is 0.2 to 2 mm.
(5) The thermoplastic resin is polyvinyl chloride (PVC), ethylene-vinyl acetate copolymer (EVA), ethylene-propylene copolymer, ethylene-methylmethacrylate copolymer (EMMA), low-density polyethylene (LDPE). The protective tube according to any one of (1) to (4), which comprises one or more kinds selected from styrene-ethylene-butylene-styrene copolymer (SEBS).
(6) The protective tube according to any one of (1) to (5), wherein the thermoplastic resin has a weight average molecular weight of 20,000 to 1,000,000.
(7) The protective tube according to any one of (1) to (6), wherein the thermoplastic resin contains a vinyl chloride resin having a weight average molecular weight of 300,000 to 500,000.
(8) A protective material for a long article made of the protective tube according to any one of (1) to (7).
(9) A protective material for a long article made of the protective tube according to (8), wherein the long article is a bundle of electric wires.
(10) A wire harness in which a bundle of electric wires is bundled using the protective tube according to any one of (1) to (9).

With the above configuration, it is possible to cover a bundle of electric wires and cables such as a wire harness for automobiles. The covered electric wire cable can be bent without applying an extra force, and the repulsive force when the bending force is removed is small, so that the protected object can be freely deformed. Further, by using the material having the above thickness and elastic modulus, wear of each electric wire due to the intrusion of sand and dust can be prevented.

An embodiment of the sheet according to the present invention is shown. An embodiment (Example 1) of the protective tube according to the present invention is shown. A form in which the protective tube according to the present invention is focused on a bundle of electric wires is shown.

The protective tube of the present invention has a tube structure as shown in FIG. 2 in which a sheet-like body made of a thermoplastic resin is wound in the circumferential direction, and has an inner end 2 and an outer end 3 in the circumferential direction in the radial direction. It is characterized in that it has a structure in which long articles such as electric wire bundles can be accommodated in the inner 4 of the protective tube by opening the outer end thereof.

The type of the thermoplastic resin of the present invention is not particularly limited, but for example, a polyolefin-based resin (low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), straight-chain low-density polyethylene). (LLDPE), etc.), copolymer of ethylene and α-olefin (propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, etc.), propylene and α-olefin (1-butene, 1-pentene, etc.) , 1-hexene, 1-octene, etc.), ethylene-propylene-diene copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl propionate copolymer Combined, ethylene-vinyl pivalate copolymer, ethylene-vinyl caproate copolymer, ethylene-vinyl caprice copolymer, ethylene-vinyl laurate copolymer, ethylene- (meth) acrylic acid ester copolymer With certain ethylene-ethyl (meth) acrylate copolymers, ethylene-methyl (meth) acrylate copolymers, ethylene-propyl (meth) acrylate copolymers, polypropylene homopolymers that are polypropylene-based resins, and propylene-ethylene copolymers. A polypropylene random copolymer, a polypropylene block polymer, a polypropylene block polymer obtained by polymerizing polypropylene and CH ₂ = CHR (R: aliphatic and aromatic having 2 to 8 carbon atoms), and an ethylene-propylene rubber (EPR) having polypropylene as a hard segment. ), Ethylene-propylene diene rubber (EPDM), acrylonitrile butadiene rubber (NBR), melt-kneading using natural rubber as a soft segment, and reactor-polymerized polypropylene polymer (TPO), styrene-ethylene-ethylene, which is an aromatic vinyl-based elastomer. Propropylene block and random copolymer (SEPS), styrene-butadiene-styrene block, and random copolymer (SBS), styrene-isoprene-styrene block, and random copolymer (SIS), and hydrogenated products thereof. , Polyethylene-based resin, low-density polyethylene, linear low-density polyethylene, etc.) and polyvinyl chloride-based resin (polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-ethylene copolymer, vinyl chloride-propylene Copolymers, chlorinated polyolefins, etc.), natural rubber, synthetic rubber (butadiene rubber, isoprene, etc.) Rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, methyl methacrylate rubber, butyl rubber, chloroprene rubber, acrylic rubber, urethane rubber, silicone rubber, etc.), thermoplastic elastomers (ethylene-propylene rubber, ethylene-propylene-diene rubber, etc.) Styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, styrene-ethylene-styrene copolymer, styrene-ethylene-butadiene-styrene copolymer, styrene-ethylene-propylene-styrene copolymer, etc.) and the like. These may be used alone or in combination of two or more. Among these, polyolefin-based resins, vinyl chloride-based resins, and styrene-based thermoplastic elastomers are preferable, and vinyl chloride-based resins and ethylene-vinyl acetate are preferable because they have appropriate flexibility and extensibility and are excellent in molding processability. Copolymers (EVA), ethylene-propylene copolymers, ethylene-methylmethacrylate copolymers (EMMA), low density polyethylene (LDPE), styrene-ethylene-butylene-styrene copolymers (SEBS) are more preferred, and chloride. Vinyl-based resins, ethylene-vinyl acetate copolymers (EVA), and ethylene-propylene copolymers are more preferable, and vinyl chloride-based resins are particularly preferable. Further, the thermoplastic resin of the present invention may contain a vinyl chloride resin having a weight average molecular weight of 300,000 to 500,000.

The weight average molecular weight of the thermoplastic resin is preferably 20,000 to 1,000,000, more preferably 100,000 to 500,000, and even more preferably 250,000 to 350,000. If the weight average molecular weight is less than 20,000, processing defects such as drawdown and wrapping around the roll are likely to occur during processing into a sheet-like body. On the other hand, if it exceeds 1 million, it becomes difficult to melt and knead with an extruder or a Banbury mixer.

Further, by containing a thermoplastic resin having a weight average molecular weight of 300,000 or more, the protective tube of FIG. 2 is less likely to collapse due to its own weight or deformation during work, and a protective tube having high shape stability can be obtained. As the thermoplastic resin, it is particularly preferable to use polyvinyl chloride (PVC) having a weight average molecular weight of 300,000 to 500,000.

The protective tube of the present invention may contain a plasticizer in order to impart appropriate flexibility, extensibility and workability. Examples of plasticizers include phthalic acid-based plasticizers, isophthalic acid-based plasticizers, terephthalic acid-based plasticizers, adipic acid-based plasticizers and their polyester-based plasticizers, phosphoric acid-based plasticizers, trimellitic acid-based plasticizers, and epoxys. A plasticizer or the like can be used. Specific examples of the plasticizer include DINP (diisonyl phthalate), DHP (diheptyl phthalate), DOP (di-2-ethylhexyl phthalate), n-DOP (di-n-octyl phthalate), DIDP (phthalic acid). Diisodecyl), DOIP (di-2-ethylhexyl isophthalate), DOTP (di-2-ethylhexyl terephthalate), BBP (benzylbutylphthalate), TOTM (tri-2-ethylhexyl trimeritate), DOA (di-2-ethylhexyl adipate) 2-Ethylhexyl), TCP (tricrezyl phosphate), BOA (benzyloctyl adipate), polyester plasticizer (adipate-propylene glycol-based polyester, adipic acid-butylene glycol-based polyester, phthalic acid-propylene glycol-based polyester, etc.) ), DPCP (diphenyl cresil phosphate), diisodecyl adipate, epoxidized soybean oil, epoxidized flaxseed oil, chlorinated paraffin and the like. These may be used alone or in combination of two or more. DINP, DOTP, TOTM, DOA, polyester plasticizer, epoxidized soybean oil, epoxidized linseed oil, and chlorinated paraffin are preferable, and DINP is more preferable.

Further, the protective tube of the present invention is a colorant, a stabilizer, an antioxidant, an ultraviolet absorber, a lubricant as an inorganic filler, a modifier, and other additives as long as it does not impair the effect of the present invention. , Pigments and the like can be included.

Examples of the inorganic filler include aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, calcium hydroxide, potassium hydroxide, barium hydroxide, triphenylphosphite, ammonium polyphosphate, polyphosphate amide, dilyconium oxide, and magnesium oxide. , Zinc oxide, titanium oxide, molybdenum oxide, guanidine phosphate, hydrotalcite, snaketite, zinc borate, zinc anhydride borate, zinc metaborate, barium metaborate, antimony oxide, antimony trioxide, antimony pentoxide, red phosphorus, Talk, alumina, silica, boehmite, bentonite, sodium silicate, calcium silicate, calcium sulfate, calcium carbonate, magnesium carbonate, carbon black, and may be used alone or in combination of two or more. It is preferably talc, alumina, silica, calcium silicate, calcium sulfate, calcium carbonate, magnesium carbonate, and more preferably calcium carbonate.

These inorganic fillers may be obtained by crushing a natural product, or may be obtained by neutralizing and precipitating an aqueous solution or the like. Further, a surface treatment agent or the like introduced with a functional group may be used. As the surface treatment agent, fatty acids, rosinic acid, lignin acid, quaternary ammonium salt and the like can be used.

Examples of the modifier include vinyl chloride-vinyl acetate copolymer, vinyl chloride-ethylene copolymer, vinyl chloride-propylene copolymer, chlorinated polyethylene, ethylene-vinyl acetate copolymer, and acrylonitrile-butadiene-styrene. Examples thereof include copolymers, methyl methacrylate-butadiene-styrene copolymers, acrylonitrile-butadiene copolymers, methyl methacrylate-butyl acrylate copolymers, thermoplastic polyurethanes, polyester-based thermoplastic elastomers and the like. These may be used alone or in combination of two or more.

As a method for incorporating an additive such as a plasticizer, an inorganic filler, a modifier, and other additives such as a colorant, a stabilizer, an antioxidant, an ultraviolet absorber, a lubricant, and a pigment into the protective tube of the present invention, as described above. Examples thereof include a method of melt-kneading a mixture of a thermoplastic resin and the additive. The melt-kneading method is not particularly limited, but various mixers and kneaders equipped with a heating device such as a twin-screw extruder, a continuous type and batch type kneader, a roll, and a Banbury mixer can be used. Is mixed so as to be uniformly dispersed, and the obtained mixture is molded into a base material by a conventional molding method such as a calendar method, a T-die method, or an inflation method. The molding machine is preferably a calendar molding machine from the viewpoints of productivity, color change, shape uniformity, and the like. As the roll arrangement method in calendar molding, for example, known methods such as L-type, inverted L-type, and Z-type can be adopted, and the roll temperature is usually set to 150 to 200 ° C., preferably 155 to 190 ° C.

The tube in which the sheet 1 made of the thermoplastic resin of the present invention is wound in the circumferential direction has a shape in which the inner end 2 and the outer end 3 in the circumferential direction are overlapped with each other in the radial direction, and the electric wire bundle has a shape. Such a long article is a protective tube having a structure capable of opening the outer end 3 and accommodating the long article in the inner 4 of the inner end 2 (FIG. 2). If the inner end 2 and the outer end 3 are not overlapped with each other in the radial direction, the wire bundle may pop out from the gap or the protective tube may come off the wire bundle.

The tube (FIG. 2) in which the sheet 1 made of the thermoplastic resin of the present invention is wound in the circumferential direction has a length in which the inner end 2 to the outer end 3 in the circumferential direction are overlapped with each other in the radial direction. It is preferably 1/8 or more and 3 or less, more preferably 1/4 or more and 2 or less, and further preferably 1/2 or more and 3/2 or less of the outer peripheral length of the cross-sectional circle of the tube structure. If the wrapped length is less than 1/8, the electric wire may pop out from the wrapped portion when the electric wire bundle is bent after covering the electric wire bundle. Further, if the wrapped length exceeds 3, the work of opening the outer end portion 3 in order to bundle the electric wire bundle becomes complicated.

The wall thickness of the tube structure of the present invention is a value obtained by dividing the difference between the outer diameter and the inner diameter of the cross-sectional circle of the tube structure by 2, and the larger the thickness of the sheet-like body 1, the longer the stacked length. The thicker the wall, the thicker it becomes. If the stacked length is not an integral multiple of the outer peripheral length of the cross-sectional circle of the tube structure, the wall thickness of the more stacked portion 7 is the thickness of the sheet-like body rather than the wall thickness of the non-stacked portion 8. It becomes thicker (Fig. 3). Here, the minimum wall thickness of the tube structure is preferably in the range of 0.2 to 2 mm, more preferably 0.3 to 1 mm, and further preferably 0.4 to 0.8 mm. If the minimum wall thickness is less than 0.2 mm, the wearability is lowered, and the protection of the wire bundle from the edge of the external interfering material or the like may be lowered. If it exceeds 2 mm, the flexibility is lowered, and when the wire bundle is covered, the flexibility of the wire bundle may be lowered.

It is essential that the 100% tensile modulus of the sheet made of the thermoplastic resin of the present invention is 200 MPa or less. It is preferably 2 to 50 MPa, more preferably 5 to 30 MPa. A protective tube having a 100% tensile modulus greater than 200 MPa is difficult to bend or twist by hand, and when the wire bundle is covered, the wire bundle cannot be moved freely, so that it cannot be suitably used as a protective tube.

The protective tube of the present invention preferably has a heat shrinkage rate of 20% or less, more preferably 10% or less, still more preferably 5% or less after 1 hour in an environment of 120 ° C. on the sheet. If the heat shrinkage rate exceeds the above-mentioned value, peeling may occur in a high temperature environment after the wires are focused.

In the protective tube of the present invention, the embrittlement temperature of the sheet according to JIS K 7216 is preferably −20 ° C. or lower, more preferably −30 ° C. or lower, still more preferably −40 ° C. or lower. If the embrittlement temperature exceeds the above-mentioned value, cracks may occur in a low temperature environment after the wire is focused.

The protective tube of the present invention may have a structure made of a single thermoplastic resin or a laminated structure made of a plurality of thermoplastic resins. Further, as long as the function of the present invention is not impaired, materials other than the thermoplastic resin, such as urethane resin, epoxy resin, phenol resin, melamine resin, urea resin, and unsaturated resin, are inside, outside, or inside the tube made of the thermoplastic resin. It may have a laminated structure with a thermosetting resin such as a polyester resin or an alkyd resin, an inorganic compound such as silica, alumina or carbon, a metal such as aluminum, nickel, copper or iron, a woven cloth or a non-woven fabric.

The protective tube of the present invention may be provided with an adhesive layer inside or outside, if necessary, in order to maintain shape stability. The adhesive strength of the adhesive layer with the sheet or the adhesive strength between the adhesive layers is preferably 0.1 N / 10 mm or more. When it is more than this value, the adhesiveness for obtaining shape stability can be sufficiently exhibited.

Since the protective tube of the present invention has electrical insulation, it can be more preferably used as a protective material for a bundle of electric wires. The volume resistivity of the tube ^{is preferably 10 10} Ωcm or more, more preferably 10 ¹¹ Ωcm or more, and further preferably 10 ¹² Ωcm or more.

Since the protective tube of the present invention has flame retardancy, it can be more preferably used as a protective material for a bundle of electric wires. The oxygen index of the tube is preferably 17 or more, more preferably 20 or more, still more preferably 23 or more.

Since the protective tube of the present invention has edge resistance, it can be more preferably used as a protective material for a bundle of electric wires. The number of reciprocations in the scrape wear test of the protective tube is preferably 50 times or more, more preferably 100 times or more, still more preferably 300 times or more, still more preferably 500 times or more.

The protective tube of the present invention can be suitably used as an exterior material for a long article such as a bundle of electric wires, and can suitably protect the bundle of electric wires from the edge of an external interference material or the like.

Further, the protective tube of the present invention can be suitably used as an exterior material of a wire harness for an automobile, and does not require pre-threading of an electric wire bundle, which is a work required for a shrinkable tube or a vinyl tube, and each member such as a connector. Can be attached to the wire bundle after being attached to the wire bundle.

Hereinafter, the present invention will be described in more detail with reference to examples. Moreover, these are merely examples and do not limit the content of the present invention.

[Example 1]
(1) Premixing: 40 parts by mass of diisononyl phthalate (manufactured by J-PLUS Co., Ltd.) as a plasticizer with respect to 100 parts by mass of polyvinyl chloride (TH1000 manufactured by Taiyo PVC Co., Ltd.) having an average degree of polymerization of 1000 (weight average molecular weight 130,000). 20 parts by mass of calcium carbonate (Calcies P, manufactured by Kamishima Chemical Industry Co., Ltd.) was blended as an inorganic filler and premixed with a tumbler (SKD-200 manufactured by Platec Co., Ltd.) for 5 minutes.
(2) Pelletization: The above mixture is melt-kneaded with a 35 mm ψ twin-screw extruder with a vent (TEM-35B manufactured by Toshiba Machine Co., Ltd.) at a screw rotation speed of 250 rpm and a cylinder temperature of the extruder at 160 ° C., and pelletized by strand cutting. did.
(3) Molding of protective tube: A 40 mm ψ single-screw extruder (FS40, manufactured by Ikekai Co., Ltd.) equipped with a die having the cross-sectional structure shown in FIG. Maximum wall thickness 1 mm, minimum wall thickness 0.5 mm, outer diameter 10 mm, length 50 mm, a part in which the inner end to the outer end in the circumferential direction are overlapped with each other in the radial direction (expressed as wrap). A protective tube having a shape shown in FIG. 2 having a circumference of 1/2 of the circumference of the circle in cross section was obtained. After the end of the obtained protective tube was opened, it was sandwiched between SUS plates weighing 1 kg and heated at 120 ° C. for 1 hour to obtain a sheet. Table 1 shows the results of the following evaluations using the obtained protective tubes and sheets.
[Examples 2-3, 7-9]
A protective tube was obtained in the same manner as in Example 1 except that the degree of polymerization of polyvinyl chloride in Example 1 was changed, and the same evaluation was performed. The polyvinyl chloride used was as follows. The results are shown in Tables 1-2.
[Examples 4 to 6]
A protective tube was obtained in the same manner as in Example 3 except that the compounding ratio of Example 3 was changed, and the same evaluation was performed. The polyvinyl chloride used was as follows. The results are shown in Table 2.
[Example 10]
A 40 mm ψ single-screw extruder (FS40, manufactured by Ikegai Co., Ltd.) equipped with a die having the cross-sectional structure shown in FIG. Extruded at a linear speed of 35 m / min, the maximum wall thickness is 1 mm, the minimum wall thickness is 0.5 mm, the outer diameter is 10 mm, the length is 50 mm, and the inner end to the outer end in the circumferential direction are overlapped with each other in the radial direction. A protective tube having a shape shown in FIG. After the end of the obtained protective tube was opened, it was sandwiched between SUS plates weighing 1 kg and heated at 120 ° C. for 1 hour to obtain a sheet. Table 2 shows the results of the following evaluations using the obtained protective tubes and sheets.
[Example 11]
Pellets of random PP (Prime Polymer Prime TPO E-2710), which is an ethylene-propylene copolymer, were obtained in a protective tube by the method described in Example 10, and the same evaluation was performed. The results are shown in Table 2.
[Examples 12 to 16]
The same method as in Example 1 except that the wrap length of Example 1 was changed, and the minimum wall thickness was further changed in Example 14, and the maximum and minimum wall thicknesses were further changed in Examples 15 and 16. A protective tube was obtained in the above and the same evaluation was performed. The polyvinyl chloride used was as follows. The results are shown in Tables 2-3.
[Examples 17 to 19]
A protective tube was obtained in the same manner as in Example 14 except that the maximum and minimum wall thicknesses of Example 14 were changed, and the same evaluation was performed. The polyvinyl chloride used was as follows. The results are shown in Table 3.
[Comparative Example 1]
TH1000 manufactured by Taiyo PVC Co., Ltd .: A protective tube having an average degree of polymerization of 1000 (weight average molecular weight of 130,000) was obtained by the method described in Example 10, and the same evaluation was performed. The results are shown in Table 4.
[Comparative Example 2]
TH1000 manufactured by Taiyo PVC Co., Ltd .: The method according to Example 10 in which 100 parts by mass of an average degree of polymerization 1000 (weight average molecular weight 130,000) and 100 parts by mass of an ethylene-vinyl acetate copolymer (Tosoh Ultrasen 640) are hand-blended. A protective tube was obtained in the above, and the same evaluation was performed. The results are shown in Table 4.
[Comparative Example 3]
A protective tube obtained by changing the compounding ratio of Example 9 by the method described in Example 9 was obtained, and the same evaluation was performed. The results are shown in Table 4.
[Comparative Example 4]
A protective tube having no wrap in Example 1 (with a wrap length of 0) was obtained by the method described in Example 1, and the same evaluation was performed. The results are shown in Table 4.
TH1000 manufactured by Taiyo PVC Co., Ltd .: Average degree of polymerization 1000 (weight average molecular weight 130,000)
TH2000 manufactured by Taiyo PVC Co., Ltd .: Average degree of polymerization 2000 (weight average molecular weight 260,000)
TH2800 manufactured by Taiyo PVC Co., Ltd .: Average degree of polymerization 2800 (weight average molecular weight 350,000)
TH3800 manufactured by Taiyo PVC Co., Ltd .: Average degree of polymerization 3800 (weight average molecular weight 470,000)
TH700 manufactured by Taiyo PVC Co., Ltd .: Average degree of polymerization 700 (weight average molecular weight 90,000)
Taiyo PVC TU400: Average degree of polymerization 4500 (weight average molecular weight 560,000)

<100% tensile modulus>
After forming the obtained sheet into the shape of a No. 3 dumbbell, the stress at 100% elongation when the test piece was subjected to a tensile test at 300 mm / min in accordance with JIS K 6251 was measured. The results are shown in Tables 1 to 4. When the elongation was less than 100%, it was described as "break".

<Heat shrinkage rate at 120 ° C>
The obtained sheet was measured according to JIS K 7133, and the dimensional change when heated at 120 ° C. for 1 hour was measured. The dimensions were measured in the tube extrusion direction (MD) and its vertical direction (TD), and the one with the larger numerical value was adopted. The results are shown in Tables 1 to 4. If the shrinkage rate exceeds 20%, the tube cannot maintain its structure in a high temperature environment, so that it cannot be used in applications requiring heat resistance.

<Emblittlement temperature>
The obtained sheets were stacked so as to have a length of 38 mm, a width of 6 mm, and a thickness of 2 mm, and the embrittlement temperature was determined based on the presence or absence of fracture when the temperature was lowered from 0 ° C in 5 ° C increments in accordance with JIS K 7216. It was measured. The results are shown in Tables 1 to 4. If the embrittlement temperature exceeds -20 ° C, cracks will occur in a low temperature environment, so it cannot be used in applications that require cold resistance.

<Workability>
When winding the obtained protective tube around a bundle of 10 low-voltage wires for automobiles (type: AV conductor size: 0.85, finished outer diameter: 2.4 mm, vinyl chloride coating), it can be wound without effort. , The case where peeling, wrinkles, and adhesion between sheets occurred during winding was evaluated as Δ, and the case where significant difficulty in winding occurred due to the above reason was evaluated as ×. The results are shown in Tables 1 to 4. If it is extremely difficult to wind it, it cannot be used as a protective material for electric wires and the like.

<Sealing>
When the wire bundle around which the obtained protective tube is wound is bent 180 degrees and twisted 360 degrees to the right and left, the wire bundle is not exposed and the protective tube does not peel off or wrinkle. Was marked with ◯, the case where the sheet was peeled off and wrinkled without exposing the wire bundle was marked with Δ, and the case where the wire bundle was exposed was marked with ×. The results are shown in Tables 1 to 4. If the wire bundle is exposed, it cannot be used as a protective material for long articles such as the wire bundle.

<Flexibility>
After winding the obtained protective tube around the wire bundle, if the end is not rolled or the wire bundle is not exposed when bent 180 degrees, the wire bundle is exposed or the protective tube is damaged by bending. The thing was set as x. The results are shown in Tables 1 to 4. If the electric wire is exposed or the protective tube is damaged by bending, it cannot be used as a protective material for the electric wire or the like.

1 ... Sheet 2 ... Inner end in the circumferential direction 3 ... Outer end 4 ... Inner side of protective tube 5 ... Inner side surface 6 ... Wire bundle 7 ... Overlapping part 8 ... Non-overlapping part

Claims (10)

A protective tube for storing long articles in which a sheet made of thermoplastic resin is wound in the circumferential direction, and has a shape in which the inner end and the outer end in the circumferential direction are overlapped with each other in the radial direction. A protective tube having a structure capable of accommodating a long article inside the inner end by opening the outer end, and having a 100% tensile modulus of the sheet of 2 to 50 MPa. The protective tube according to claim 1, wherein the sheet has a heat shrinkage rate of 20% or less after heating at 120 ° C. for 1 hour. The protective tube according to claim 1 or 2, wherein the embrittlement temperature of the sheet is −20 ° C. or lower. The protective tube according to any one of claims 1 to 3, wherein the minimum wall thickness of the tube is 0.2 to 2 mm. The thermoplastic resin is polyvinyl chloride (PVC), ethylene-vinyl acetate copolymer (EVA), ethylene-propylene copolymer, ethylene-methylmethacrylate copolymer (EMMA), low density polyethylene (LDPE), styrene-. The protective tube according to any one of claims 1 to 4, which comprises one or more kinds selected from an ethylene-butylene-styrene copolymer (SEBS). The protective tube according to any one of claims 1 to 5, wherein the thermoplastic resin has a weight average molecular weight of 20,000 to 1,000,000. The protective tube according to any one of claims 1 to 6, wherein the thermoplastic resin contains a vinyl chloride resin having a weight average molecular weight of 300,000 to 500,000. A protective material for a long article made of the protective tube according to any one of claims 1 to 7. The protective material for a long article, which comprises the protective tube according to claim 8, wherein the long article is a bundle of electric wires. A wire harness in which a bundle of electric wires is bundled using the protective tube according to any one of claims 1 to 9.

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