JP2001219500A - Resin coated flexible steel pipe and resin composition thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin coated flexible steel pipe not bringing about the generation of harmful gas or environmental pollution at a time of incineration and capable of improving the bending properties of a flexible steel pipe. SOLUTION: In the resin coated flexible steel pipe 3 constituted of a raw pipe 1 and the outer layer 2 applied to the outer surface of the raw pipe 1 by resin coating, the outer layer 2 is formed using a composition prepared by mixing 20-300 parts by weight of an inorganic filler with 100 parts by weight of a thermoplastic elastomer containing no halogen substance. By this constitution, the resin coated flexible steel pipe excellent in various characteristics such as bending properties, preservation of environment or the like is obtained while preventing environmental pollution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-coated flexible steel pipe and a resin composition thereof, and more particularly to a resin-free flexible steel pipe which is provided with a coating made of a resin composition containing no halogen-based substance as an outer layer. The present invention relates to a resin-coated flexible steel pipe having heat resistance, oil resistance, bendability, and the like, and a resin composition thereof.

[0002]

2. Description of the Related Art A flexible steel pipe is used for indoor piping from the viewpoint of workability. Further, for the purpose of protecting the flexible steel pipe, a resin-coated flexible steel pipe obtained by coating a steel pipe with a resin is also used. The resin-coated flexible steel pipe needs to have flame retardancy, heat resistance, solvent resistance, flexibility, and the like. As a resin material used for coating, polyvinyl chloride (hereinafter, referred to as PVC) is generally used. ing. The reason is that PVC is excellent in appearance, flexibility, heat resistance, solvent resistance, flame retardancy and inexpensive.

[0003] However, if PVC is used as the coating resin, a large amount of corrosive hydrogen chloride gas is generated when incinerated by disposal or the like, and extremely toxic when incinerated under inappropriate conditions. There is a concern that dioxin will be generated. In addition, when landfilled, lead ions generated from a lead compound added as a stabilizer may elute into groundwater and pollute the environment. To solve such a problem, for example, Japanese Patent Application Laid-Open No. H10-56
There is a resin-coated flexible steel pipe disclosed in Japanese Patent Application Publication No. 92-92, in which the surface of a raw pipe (steel pipe) is coated with a polyolefin resin to which a halogen-free flame retardant is added to a predetermined thickness.

[0004]

However, according to the conventional resin-coated flexible steel pipe, generation of harmful gases such as hydrogen halide and dioxin during incineration and environmental pollution are eliminated, but the coated resin and the original pipe are not affected. However, if the coating resin impairs the bendability of the flexible steel pipe, the flexible pipe will be bent at a significantly smaller curvature than the natural bending curvature of the original pipe. Such a situation causes the natural flow of various gases flowing in the pipe to be hindered.

[0005] Accordingly, an object of the present invention is to provide a resin-coated flexible steel pipe and a resin composition thereof, which do not generate harmful gas or environmental pollution at the time of incineration and can improve the flexibility of the flexible steel pipe. To provide.

[0006]

In order to achieve the above object, the present invention has, as a first feature, a resin-coated flexible steel pipe composed of a steel pipe and an outer layer in which the outer surface of the steel pipe is coated with a resin. Wherein the outer layer is a resin composition comprising 100 parts by weight of a thermoplastic elastomer not containing a halogen substance, and 20 to 300 parts by weight of an inorganic filler mixed with the thermoplastic elastomer. Provide a coated flexible steel pipe.

According to this configuration, the halogen-free thermoplastic elastomer does not generate a halogenated gas at the time of incineration, and also contains a harmful heavy metal such as a lead or a halogen-based substance which causes environmental pollution. No lead ions are generated. The inorganic filler in which 20 to 300 parts by weight is mixed with 100 parts by weight of the thermoplastic elastomer reduces the degree of adhesion between the original tube and the outer layer, thereby securing the natural bending curvature of the original tube (steel tube). Therefore, it is possible to obtain a resin-coated flexible steel pipe that does not generate harmful gas or incur environmental pollution at the time of incineration disposal and that has improved flexibility of the flexible steel pipe.

In order to achieve the above object, the present invention has, as a second feature, 100 parts by weight of an olefin-based thermoplastic elastomer in which polypropylene and a soft polyolefin are mixed, and the olefin-based thermoplastic elastomer is mixed. A resin composition for a resin-coated flexible steel pipe, comprising 20 to 300 parts by weight of an inorganic filler.

According to this structure, since the olefin-based thermoplastic elastomer in which the polypropylene and the soft polyolefin are mixed does not contain a halogen substance, the olefin-based thermoplastic elastomer does not generate a halogenated gas even if it is incinerated, and has a low environmental pollution. Since it does not contain harmful heavy metals such as halogen-based substances or lead, it does not generate lead ions. And 1
When a composition obtained by mixing 20 to 300 parts by weight of an inorganic filler with 00 parts by weight of a thermoplastic elastomer is used as an outer layer of a resin-coated flexible steel pipe, the composition may be used to reduce the degree of adhesion between the original pipe (steel pipe) and the outer layer. It functions and ensures the natural bending curvature of the original tube. Therefore, generation of harmful gas and environmental pollution at the time of incineration do not occur, so that even when used for a resin-coated flexible steel pipe used for indoor piping or the like, the flexibility of the resin-coated flexible steel pipe can be improved. .

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a resin-coated flexible steel pipe according to the present invention. The resin-coated flexible steel pipe 3
It comprises an original tube 1 which is a main component of a flexible steel tube, and an outer layer 2 which covers the original tube 1. The outer layer 2 uses a resin material described below. The present inventors have studied various resin compositions containing no halogen-based substance as the material used for the outer layer 2. In addition, various fillers, additives, etc. were studied to control the adhesion between the coated resin and the metal flexible raw pipe, which greatly affects the piping properties of the resin-coated flexible steel pipe. As a result, when a composition obtained by mixing 20 to 300 parts by weight of an inorganic filler with respect to 100 parts by weight of a thermoplastic elastomer (TPE) containing no halogen substance is used for the outer layer 2, no halogenated gas is generated during incineration. It has been found that it is possible to provide a resin-coated flexible steel pipe which has clean characteristics free of harmful heavy metals such as lead and has excellent bending properties.

As the inorganic filler, calcium carbonate, talc, soft clay, hard clay, calcined clay, silica, zinc oxide, mica powder, molybdenum disulfide, glass fiber, glass beads, graphite, carbon black and the like can be used. it can. Among them, calcium carbonate
Optimum because it is easy to knead into the resin and the decrease in mechanical properties is small. Calcium carbonate includes synthetic calcium carbonate (light calcium carbonate) having small particles and heavy calcium carbonate obtained by mechanically pulverizing coarse limestone. Heavy calcium carbonate is preferable because of good kneading processability. Among them, those having an average particle diameter of 1 to 4 μm are excellent in workability and product appearance and are most suitable.

When laying a resin-coated flexible steel pipe in a building, bending is performed according to the structure of the building. At this time, in the resin-coated flexible steel pipe 3 in which the adhesion between the outer layer 2 and the original pipe 1 is strong, the outer layer 2 impairs the bendability of the original pipe 1, and has a significantly smaller curvature than the natural bending curvature of the original pipe 1. It will be bent by. This condition is a factor that hinders the natural flow of various gases flowing in the pipe.

However, by blending the inorganic filler, the resin-coated flexible steel pipe 3 can have a natural bending curvature. This is due to the addition of inorganic fillers
This is because the adhesion between the coating resin and the original tube has been reduced. In this case, if the added amount of the inorganic filler is less than 20 parts by weight, the effect of adding the inorganic filler is hardly exhibited. When the amount exceeds 300 parts by weight, the rubber elasticity of the thermoplastic elastomer is lost,
In particular, a significant deterioration occurs in low-temperature characteristics.

Here, the thermoplastic elastomer will be described in detail. Thermoplastic elastomer is a polymer material which exhibits the properties of vulcanized rubber at normal temperature, but is plasticized at high temperature and can be molded using a plastic processing machine. A flexible component (soft segment) having rubber elasticity in the molecule;
It has a molecular constraint (hard segment) to prevent plastic deformation. There is a characteristic that the hard phase is plasticized by heating and re-hardened when cooled. Examples of the thermoplastic elastomer include styrene-based, ester-based, urethane-based, amide-based, and olefin-based thermoplastic elastomers. Hereinafter, each will be described in detail.

The styrene-based thermoplastic elastomer is a styrene-based block copolymer, and SBS (PS (polystyrene) -polybutadiene-PS) or SIS (PS-polyisoprene P), depending on the type of soft segment.
S), SEBS (PS-polyethylene / butylene-P
S) and the like. From the viewpoint of heat resistance, SEBS containing no double bond in the molecular main chain is preferable.

The ester-based thermoplastic elastomer has PBT (polybutylene terephthalate) and PET (polyethylene terephthalate) as hard segments,
It is a generic term for those having a soft polyester copolymer as a soft segment, and the soft segment is PTMG.
There are polyether / ester copolymers comprising a condensate of (polytetramethylene glycol) and terephthalic acid, and polyester / ester copolymers using polycaprolactone.

In the urethane-based thermoplastic elastomer, the hard segment is polyurethane, and there are a polyester type and a polyether type depending on the type of the soft segment. Further, examples of the polyester type include a caprolactone type, an adipate type, and a polycarbonate type. From the viewpoint of water resistance, a polyether type or a polycarbonate type, which is hardly hydrolyzed, is preferable. The amide-based thermoplastic elastomer is a thermoplastic elastomer in which nylon 6, 66, 11, 12 or the like is used as a hard segment and polyether or polyester is used as a soft segment.

The olefin-based thermoplastic elastomer is a thermoplastic elastomer having a hard segment of a polyolefin resin, and includes a blend type and a copolymer type. It is most suitable among thermoplastic elastomers because of its excellent cold resistance and low cost. Here, the hard segment refers to the polymer component of the composition in the range of 15% to 95% by weight. Among the olefinic thermoplastic elastomers, dynamically vulcanized EP
Those having DM in the soft segment are most preferred from the viewpoint of heat resistance and oil resistance. A blend of an elastomer containing a styrene component having good compatibility with PP is excellent in kneading processability and can be plasticized without adding a plasticizer or a softening agent such as process oil. , PS, ABS, etc.) are preferable since they do not affect them at all.

As the hard segment, a crystalline polyolefin is required, and PP (polypropylene), HDPE (high-density polyethylene), or LDP
E (low density polyethylene) and the like. Soft segments include EPM (ethylene propylene rubber), EPDM (ethylene propylene diene copolymer rubber), NBR (acrylonitrile-butadiene rubber),
Hydrogenated NBR, EOR (ethylene-octene copolymer rubber), EBR (ethylene-butene-1 copolymer rubber), LLDPE (linear low-density polyethylene), VL
DPE (ultra low density polyethylene), EEA (ethylene-
Ethyl acrylate copolymer), EVA (ethylene-vinyl acetate copolymer), and elastomers containing a styrene component.

The elastomer containing a styrene component includes S
BS (PS (polystyrene) -polybutadiene-P
S), SIS (PS-polyisoprene-PS), SEB
S (PS-polyethylene / butylene-PS) and other styrene-based thermoplastic elastomers, as well as SBR
(Styrene-butadiene rubber), hydrogenated SBR, SI
S (styrene-isoprene rubber), styrene-polyethylene copolymer, styrene-vinyl acetate copolymer and the like. Hydrogenated SBR having excellent compatibility with polypropylene is preferred. In addition, there are those in which the soft segment is partially crosslinked with an organic peroxide or the like, and those in which the soft segment dispersed at the time of kneading is completely crosslinked (dynamic vulcanization). Examples of the polypropylene include a homopolypropylene containing no ethylene component and a random polypropylene that is a random copolymer of ethylene. Homopolypropylene having a high crystal melting point and excellent heat resistance is preferred.

Further, according to the study of the present invention, it has been found that the outer layer 2
In the resin material, the main component of the thermoplastic elastomer containing no halogen substance is an olefin-based thermoplastic elastomer composed of a mixture of polypropylene and a soft polyolefin, and having a composition ratio of 15/85 to 95/5. In some cases, it was found that the impact characteristics at low temperatures were excellent. If the polypropylene is less than the above composition ratio, it does not function as a hard segment, so that sufficient heat resistance and oil resistance as a thermoplastic elastomer cannot be obtained. Also, when the polypropylene exceeds the above composition ratio,
Since the number of soft segments is too small, sufficient rubber elasticity as a thermoplastic elastomer cannot be obtained, and in particular, the bending characteristics of the resin-coated flexible steel pipe are significantly reduced.

In the olefin-based thermoplastic elastomer containing a mixture of polypropylene and a soft polyolefin as a main component, when the polypropylene has a morphology that forms a continuous phase of the composition, the high melting point characteristic of polypropylene is a material having a high melting point. Because it is reflected in the characteristics,
Heat resistance can be increased. In addition, if the polypropylene forms the continuous phase of the composition, the extrusion coatability can be improved. Most preferably, in the olefin-based thermoplastic elastomer containing a mixture of the polypropylene and the soft polyolefin as a main component, the soft polyolefin is an ethylene-propylene-diene terpolymer,
And it is the case where it is crosslinked. This makes it possible to improve oil resistance.

In the olefin-based thermoplastic elastomer containing a mixture of the polypropylene and the soft polyolefin as a main component, when the soft polyolefin is an elastomer containing a styrene component, the soft polyolefin has excellent compatibility with the polypropylene. It was found that kneading processability was excellent.

Further, the inorganic filler is added to 100 parts by weight of the halogen-free thermoplastic elastomer.
In the resin-coated flexible steel pipe 3 in which the composition mixed with 0 to 300 parts by weight is used for the outer layer 2, 1 to 300 parts by weight of the non-halogen flame retardant is contained in the outer layer 2 based on 100 parts by weight of the resin component in the composition. When mixed, the flame retardancy is improved, so that the safety of the product can be improved. Flame retardants include metal hydroxides, metal oxide compounds, phosphorus compounds and the like. These flame retardants can be used alone or in combination of two or more.

Examples of metal hydroxide-based flame retardants include magnesium hydroxide, aluminum hydroxide, hydrotalcite, calcium aluminate hydrate, calcium hydroxide, barium hydroxide, hard clay and the like. In particular, magnesium hydroxide having an average particle size of 8 μm or less is most preferable because of its excellent flame retardancy and excellent appearance during molding. This is because if there is a large amount of coarse particles, irregularities of the coarse particles will appear on the surface of the molded article during extrusion molding of the coating material.

The metal oxide compounds include antimony oxide, aluminum oxide, magnesium oxide and the like. Examples of the phosphorus compound include red phosphorus, phosphate ester, phosphonate, and phosphorinene.
In particular, the addition of red phosphorus is highly effective in improving flame retardancy. In addition, additives such as an antioxidant, a lubricant, a surfactant, a colorant, a softener, a plasticizer, an inorganic filler, and a compatibilizer can be added to these resin compositions as needed. In addition, the above various additives can be surface-treated with a fatty acid metal salt, a silane-based, and a titanate-based coupling agent or an acrylic resin according to an ordinary method in consideration of kneading processability, extrusion processability, and water resistance. It is.

Next, an embodiment of the present invention will be described.
2 and 3 show examples of the present invention, and FIG. 4 shows a comparative example. The resin compositions and the resin-coated flexible steel pipes shown in Examples 1 to 18 of FIGS. 2 and 3 and Comparative Examples 1 to 4 of FIG. 4 were produced in the following manner. A polymer and various compounding agents were charged into a 30 mm twin-screw kneading extruder preheated to 200 to 250 ° C and kneaded to obtain a resin composition. This kneaded material was pelletized and used as a material for producing a resin-coated flexible steel pipe. Using this pelletized material, an outer diameter of 2
A resin in which an outer layer having a thickness of 0.75 mm is formed by extruding a tube on a 4.2 mm stainless steel bellows-shaped flexible steel pipe original tube (standard specification for stainless steel flexible pipe for gas; Japan Gas Association, 20A). A coated flexible steel pipe was made. The extrusion temperature in this case is 150 to
The temperature was 250 ° C.

Next, the resin-coated flexible steel pipe produced by the following method was evaluated. FIG. 5 shows a bending radius 4 when a 90 ° bending test of the resin-coated flexible steel pipe was performed in the evaluation of the resin-coated flexible steel pipe. (A) Bending test: In accordance with the method of the standard specification, 1
When 80 ° bending is performed, after 8 times, the coating has no cracks and the pipe has airtightness. When 90 ° bending is performed without using a cylinder, the bending property of the original pipe is reduced. The bendability was evaluated from the three viewpoints of not hindering and observing the degree of whitening of the coating of the bent portion.

The bendability when 90 ° bending was performed without using a cylinder was measured by measuring a bending radius 4 in the state shown in FIG. 5, and a raw tube having the same shape without the outer layer 2 (coating) was similarly bent. The ratio to the bending radius in the case (bending radius ratio = bending radius of cladding tube / bending radius of original tube) was calculated. Here, when the bending radius ratio was 0.4 to 1.20, the bending property was determined to be “good”, and when the bending radius ratio was 0.70 to 1.20, it was determined to be “excellent”. The whitening of the outer layer 2 is caused by the deformation of the outer layer 2 at a wrinkle portion or a bent portion caused by bending of the resin-coated flexible steel pipe 3. ).
The above items were comprehensively evaluated, and excellent bendability (double circle), good (O), and poor (X) were determined.

(B) Low temperature test: In a temperature environment of -15 ° C., the operation of bending the resin-coated flexible steel pipe 3 by 180 ° using a cylinder having a diameter of 50 mm was alternately repeated left and right eight times in total. The outer layer 2 was observed for cracks, cracks, cracks and the like due to this bending. Those in which cracks, cracks, and cracks in the outer layer 2 were recognized were rejected (x), and those in which these were not recognized were evaluated as good (o). Further, in the test under a temperature environment of -40 ° C, a sample in which no crack, crack or crack of the outer layer 2 was observed was evaluated as excellent (double circle).

(C) High-temperature edible oil resistance: A resin-coated flexible steel pipe was bent at 180 ° using a cylinder having a diameter of 50 mm, and immersed in soybean oil whose bent portion was heated to 155 ° C for 24 hours. After being taken out of the oil, the outer layer 2 was observed for melting, cracks, cracks and the like. Melting, cracking of the outer layer 2,
Those with cracks etc. were rejected.

(D) Oil resistance: The outer layer 2 was peeled off from the resin-coated flexible steel pipe subjected to the heat resistance test, and the peeled outer layer 2 was punched out with a JIS No. 3 dumbbell, and a tensile test was performed. Further, the residual ratio was calculated when compared with the tensile strength of the initial product before immersion. Tensile strength (TB) residual ratio is 6
0% or more is good (○), 80% or more is excellent (double circle), 60
% Was regarded as rejected (x).

(C) Kneading processability: When preparing the resin composition by kneading, the load current in the twin-screw extruder is monitored, and the load is 15 A with respect to the allowable current (20 A) of the driving motor.
Less than, excellent kneading processability (double circle), 15A-2
A sample of 0A was judged as good (○), and one exceeding 20A was judged as poor kneading processability (x).

(D) Flame retardancy: The surface of the prepared resin-coated flexible steel pipe 3 is a Bunsen burner (flame port inner diameter 10
mm, flame length 40mm) about 10mm from the lower end of the reducing flame
The resin-coated flexible steel pipe 3 was held in a distant position, placed in a flame for 5 seconds or 15 seconds, taken out, and observed for combustion. When the flame is indirectly fired for 5 seconds, the resin is not ignited, or when the flame is extinguished within 5 seconds after taking out even if it is ignited, the resin is marked as ○. The case where the flame extinguished within 5 seconds or less after the removal was rated as a double circle, the ignition was further performed within 5 seconds, and the case where burning continued for 5 seconds or more after removal was rated as x. In addition, hydrogen chloride (HCl) gas is generated
It was judged that the environmental load was large.

As is apparent from FIGS. 2 and 3, Examples 1 to 18 according to the present invention all have bending property, low-temperature properties,
It can be seen that it has excellent heat resistance, oil resistance, kneading workability, and flame retardancy, and has a small environmental load. Of these, Examples 1 to 1
Nos. 4 and 18 are examples of olefin thermoplastic elastomers, and Examples 15 to 17 are examples of ester, urethane and amide thermoplastic elastomers. Comparing Example 1 in which the inorganic filler was not added and Examples 2 to 14 in which the inorganic filler was added, Examples 2 to 14 had a 90 ° bending radius improved, and that the bendability was improved. I understand.

In Examples 1 to 14 and 18 using an olefin thermoplastic elastomer, the other Examples 15 to 17 were used.
The low-temperature characteristics are more excellent than those of. Examples 1, 5, 1 wherein a softener was crosslinked by adding a crosslinking agent during kneading.
Example 3 has the same composition and is not crosslinked.
4, etc., have improved oil resistance. Examples 6, 7, 10, and 10 comprising an elastomer containing polypropylene and a styrene component among olefin-based thermoplastic elastomers.
No. 11 is more excellent in kneading workability than the other examples.
The cause is considered to be good compatibility between the polypropylene and the elastomer containing the styrene component. further,
Example 14 in which a non-halogen flame retardant was added has improved flame retardancy as compared with the other examples.

On the other hand, Comparative Examples 1 to 4 shown in FIG. 4 show bending properties, low-temperature properties, heat resistance, oil resistance, kneading workability, flame retardancy,
One of the environmental loads was rejected. Comparative Example 1 in which PVC was used for the outer layer 2 showed that hydrogen chloride (H
Since Cl) gas is generated, the environmental load is large. In Comparative Example 2 in which the amount of the inorganic filler added was excessive, the rubber elasticity as a thermoplastic elastomer was lost, and cracking was confirmed in a low-temperature resistance test, and the sample was rejected. In addition, the kneading processability was significantly reduced. Further, Comparative Example 3, in which the amount of the soft polyolefin added was too small, did not fulfill the function of the soft segment, and thus was inferior in rubber elasticity as a thermoplastic elastomer. For this reason, the bendability of the original flexible steel pipe was significantly impaired, and the bending test failed. Also,
A remarkable whitening phenomenon peculiar to crystalline polyolefin is observed at the bent portion, and there is a defect in appearance. Further, Comparative Example 4 in which the amount of polypropylene is too small is inferior in heat resistance and oil resistance as a thermoplastic elastomer.

[0038]

As described above, according to the resin-coated flexible steel pipe of the present invention, the outer layer coated on the steel pipe reduces the adhesion between the steel pipe and the outer layer to 100 parts by weight of a thermoplastic elastomer containing no halogen substance. 20 to 300 parts by weight of an inorganic filler that has the effect of producing harmful gases such as hydrogen halide and dioxin during incineration, and halogen-based substances and lead that cause environmental pollution. And a resin-coated flexible steel pipe excellent in various properties such as environmental preservation, bending properties, low-temperature properties, heat resistance, oil resistance, kneading workability, and flame retardancy.

Further, according to the resin composition of the present invention, 20 to 30 parts by weight of 100 parts by weight of an olefin-based thermoplastic elastomer in which polypropylene and a soft polyolefin are mixed.
Since 0 parts by weight of the inorganic filler is mixed, the olefin-based thermoplastic elastomer does not contain a halogen substance, so that it does not generate a halogenated gas even when incinerated and does not cause environmental pollution. In addition, the inorganic filler,
When used for the outer layer of the resin-coated flexible steel pipe, the degree of adhesion to the original pipe surface is reduced, and the natural bending curvature of the original pipe can be secured. As a result, no harmful gas is generated during incineration and no environmental pollution is caused.Therefore, even when used for resin-coated flexible steel pipes, there is no need to worry about environmental pollution when incinerated or landfilled. The flexibility of the coated flexible steel pipe can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a resin-coated flexible steel pipe according to the present invention.

FIG. 2 is an explanatory view showing first to fourteenth embodiments of the present invention.

FIG. 3 is an explanatory view showing fifteenth to eighteenth embodiments of the present invention.

FIG. 4 is an explanatory diagram showing a comparative example.

FIG. 5 is a front view showing a state after a 90 ° bending test of the resin-coated flexible steel pipe for evaluation of the resin-coated flexible steel pipe.

[Explanation of symbols]

 Reference Signs List 1 original pipe 2 outer layer 3 resin-coated flexible steel pipe 4 bending radius

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B05D 7/24 303 B05D 7/24 303Z B32B 1/08 B32B 1/08 B C08K 3/00 C08K 3/00 5/49 5/49 C08L 23/12 C08L 23/12 23/16 23/16 53/02 53/02 101/00 101/00 F16L 9/14 F16L 9/14 (72) Inventor Kiyoshi Watanabe Hitachi, Ibaraki 5-1-1 Hidaka-cho, Hitachi Power Systems Research Laboratory, Hitachi Cable, Ltd. (72) Inventor Ryutaro Kikuchi 5-1-1, Hidaka-cho, Hitachi, Ibaraki Pref. Hitachi Cable, Ltd. Hidaka Factory (72) Invention Person Minoru Fujiyoshi 2nd Daifuku Kuwana-shi, Mie Hitachi Metals Co., Ltd. Kuwana Plant (72) Inventor Yoshihiro Usami 2nd Daifuku Kuwana-shi, Mie Hitachi Metals Co., Ltd. Kuwana Plant (72) Inventor Hiroshi Haseda 2nd Daifuku, Kuwana-shi, Mie Hitachi Metals, Inc. Kuwana Plant (72) Inventor Takashi Tokoku 2nd Daifuku, Kuwana-shi, Mie, Hitachi Metals Ltd. Kuwana Plant, F-term 3H111 AA01 AA02 BA03 BA15 BA34 CB03 CB08 DA11 DA26 DB18 4D075 CA03 CA13 CA18 CA44 CA50 DA17 DA20 DB02 DB04 DC01 EA15 EA17 EB12 EB13 EB14 EB19 EB20 EB22 EB35 EB37 EB38 EB39 EB56 EC01 EC02 EC03 EC04 EC13 EC22 EC24 EC54 EC60 4F100 AA01AAAAAAAAAABAH AD01H AG00H AK01B AK03B AK07B AK12B AK75B AL05B AL09B BA02 CA08B CA23B DA11 DG01H GB07 GB51 JB07 JB16B JB20B JJ03 JJ07 JK13B JK17 JK17A JL00 4J002 AC072 AC112 BB031 BB052 BB062 BB121 BB152 BP011 BP031 CF101 CF191 CK031 CK041 CK051 CL071 CL081 DA036 DA057 DE077 DE087 DE106 DE127 DE147 DE236 DE287 DG026 DJ006 DJ016 DJ036 DJ046 DJ056 DL006 EW047 EW127 FA046 FD016 FD137 GL00

Claims (13)

[Claims] 1. A resin-coated flexible steel pipe comprising a steel pipe and an outer layer resin-coated on the outer surface of the steel pipe, wherein the outer layer comprises: 100 parts by weight of a thermoplastic elastomer containing no halogen substance; A resin-coated flexible steel pipe comprising a resin composition containing 20 to 300 parts by weight of an inorganic filler mixed with an elastomer. 2. The thermoplastic elastomer according to claim 1, wherein the thermoplastic elastomer is a mixture of polypropylene and a soft polyolefin, and has a composition ratio of 15/85 to 95/5. Resin-coated flexible steel pipe. 3. The soft polyolefin is ethylene-
The resin-coated flexible steel pipe according to claim 2, which is a propylene-gen terpolymer and is crosslinked. 4. The soft polyolefin is an elastomer containing a styrene component.
The resin-coated flexible steel pipe as described in the above. 5. The inorganic filler is calcium carbonate, talc, soft clay, hard clay, calcined clay, silica, zinc oxide, mica powder, molybdenum disulfide, glass fiber, glass beads, graphite, or carbon black. The resin-coated flexible steel pipe according to claim 1, wherein: 6. The outer layer contains a non-halogen flame retardant in an amount of 1 to 300 parts by weight based on 100 parts by weight of a resin component of the resin composition.
The resin-coated flexible steel pipe according to claim 1, which is mixed with parts by weight. 7. The resin-coated flexible steel pipe according to claim 6, wherein the non-halogen flame retardant contains a metal hydroxide, a metal oxide compound, or a phosphorus compound. 8. The metal hydroxide is magnesium hydroxide, aluminum hydroxide, hydrotalcite, calcium aluminate hydrate, calcium hydroxide, barium hydroxide, or hard clay, and the metal oxide compound is , Antimony oxide, aluminum oxide, or magnesium oxide, wherein the phosphorus compound is red phosphorus, phosphate ester,
The resin-coated flexible steel pipe according to claim 7, which is phosphonate or phosphorine. 9. The composition according to claim 1, further comprising: 100 parts by weight of an olefin-based thermoplastic elastomer obtained by mixing polypropylene and a soft polyolefin; and 20 to 300 parts by weight of an inorganic filler mixed with the olefin-based thermoplastic elastomer. A resin composition for a resin-coated flexible steel pipe. 10. The resin composition for a resin-coated flexible steel pipe according to claim 9, wherein the soft polyolefin is an ethylene-propylene-gen terpolymer and is crosslinked. 11. The resin composition for a resin-coated flexible steel pipe according to claim 9, wherein the soft polyolefin has a composition ratio with the polypropylene of 15/85 to 95/5. 12. The inorganic filler comprises calcium carbonate,
The resin-coated flexible steel pipe according to claim 9, which is talc, soft clay, hard clay, calcined clay, silica, zinc oxide, mica powder, molybdenum disulfide, glass fiber, glass beads, graphite, or carbon black. Resin composition. 13. The resin composition of claim 9, wherein the olefin-based thermoplastic elastomer contains 1 to 300 parts by weight of a non-halogen flame retardant.