JP2003294188A - Thermal shrinkable pipe joint and pipe junction part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal shrinkable pipe joint with an excellent result of the linear negative pressure test. <P>SOLUTION: The thermal shrinkable pipe joint is constituted by using a thermoplastic elastomer whose 100% tensile stress is 1.0 MPa to 4.5 MPa and elongation is 200% to 1000%. When the pipe joint of a length (Le) and an inside diameter (De) is thermally contracted in a free condition, the relation between the inside diameter (Do) after contraction, the thickness (to) after contraction, the outside diameter (Dp) of the pipe to be jointed and the thickness (tp) of the pipe to be jointed satisfies the following four expressions. 1<(De)/(Dp), 1.2≤(Dp)/(Do)≤2.5, 0.35≤(Le)/(Dp)≤3.0, and 1.0≤(to)/(tp)≤4.0. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a heat shrinkable pipe joint,
More specifically, it relates to a heat-shrinkable pipe joint excellent in mechanical strength, weather resistance, chemical resistance, heat resistance and rubber elasticity, and particularly to a heat-shrinkable pipe joint which is a tubular molded body.

[0002]

2. Description of the Related Art Conventionally, for joining pipes, a method of directly joining the pipe bodies to each other, a method of joining the flange portions provided on the pipe body to each other by screwing, one receiving end of the pipes and the other of the straight pipes The method of inserting and joining, the method of using a tubular joint and inserting a pipe from both ends, and joining are used. In a method other than welding, a separately molded rubber packing or the like is inserted into the joint portion in order to enhance airtightness. Although these joining methods have sufficient airtightness immediately after joining, they are poor in flexibility.Therefore, when stress is applied to the joint, the airtightness may be reduced or the joint or the pipe body may be cracked. is there.

Further, in JP-A-57-187214, a tube element made of polyvinyl chloride containing a cross-linking agent is chemically cross-linked, followed by heat expansion to an inner diameter larger than the finished inner diameter and cooling under expansion. Although a method for obtaining a title tube having a large shrinkage ratio and excellent mechanical properties is disclosed, when the heat-shrinkable tube obtained from the present invention is applied to a pipe joint, the tightening stress is small and the seal is small. Lack of sex.

Further, Japanese Patent Application Laid-Open No. 9-278910 discloses a mixture of ethylene-α olefin copolymer reacted with a single-site catalyst, low density polyethylene and a large amount of filler, etc. A tube is disclosed. This method requires a vulcanization step and is inferior in productivity, and when the heat-shrinkable tube obtained from this invention is applied to a pipe joint, the permanent elongation of the vulcanized rubber is large and the shrinkage ratio is insufficient, resulting in insufficient Sealing cannot be obtained.

Patent application Sho 56-28436 Medium and low pressure linear low density PE (LLDPE) and ethylene-vinyl acetate copolymer (EVA) or high pressure branched low density PE
A method for producing a shrink tube having a high heat shrinkage by irradiating a polymer composition composed of a mixture with (BLDPE) with an accelerated electron beam is disclosed. However, this method requires a large-scale molding device. When the heat-shrinkable tube obtained from the present invention is applied to a pipe joint, the rubber elasticity of the tube is insufficient, the tightening force is insufficient, and sufficient sealing performance cannot be obtained.

Further, in JP-A-61-76345, ethylene-
By using α-olefin copolymer as a base resin and adding vinyltrimethoxysilane and triallyl isocyanurate, a heat shrinkable tube having a large draw ratio can be produced without requiring expensive equipment. Although a method is disclosed, this method requires a long time after the molding to complete the silane crosslinking, resulting in poor productivity.

Japanese Patent Publication No. 6-62816 discloses a heat-shrinkable thermoplastic elastomer obtained by dynamically vulcanizing an ethylene / vinyl acetate copolymer and a butyl rubber mixture. The heat-shrinkable thermoplastic elastomer obtained from the present invention is disclosed. When a flexible tube is applied to a pipe joint, the residual elongation is large and sufficient heat shrinkage cannot be obtained.

Japanese Examined Patent Publication No. 3-60664 describes ethylene 1-
An invention relating to a heat-shrinkable rubber comprising a crosslinked stretched butene / polyene random copolymer rubber is disclosed. When the heat-shrinkable tube obtained from this invention is applied to a pipe joint, it can shrink at a low temperature of about 40 ° C, but it naturally shrinks during storage, resulting in a reduction in size, which causes a problem that the pipe cannot be inserted. There is.

Further, Japanese Patent Publication No. 9-309986 discloses that
An invention relating to a film, sheet or tubular heat-shrinkable molded article in which polypropylene is finely dispersed in ethylene / α-olefin / polyene random copolymer rubber is disclosed. The heat-shrinkable vulcanized rubber tube obtained from this invention had sufficient rubber elasticity, but had a high shrinkage temperature, and in order to obtain a shrinkage ratio of 20% or more in a short time,
Since it requires a shrinkage temperature of 0 ° C or higher, it cannot be used as a pipe joint for resin products having relatively low melting points such as polyvinyl chloride and polyethylene.

Further, Japanese Patent Laid-Open No. 11-218267 discloses a room temperature shrinkable tube for inserting a cylindrical inner core into a shrinkable tube, pulling out the inner core at the time of use, and shrinking the expanded tube. Although disclosed, when the heat-shrinkable tube obtained from the present invention is applied to a pipe joint, there are problems that workability is impaired and a core material is generated as a waste material.

Therefore, the pipe joint has little natural shrinkage during storage, and the shrinking temperature is 50 to 120 ° C., which is lower than the melting point of general-purpose polyvinyl chloride or polyethylene molded products, and the pipes are easily joined and airtight. The appearance of heat-shrinkable pipe joints with high mechanical strength and flexibility is desired.

In recent years, information boxes for storing optical cables, common grooves for storing electric cables and communication cables, and burying of highly watertight drainage pipes have become popular for advanced computerization, disaster prevention, and environmental improvement. These are made of polyvinyl chloride or polyethylene in units of several meters, and in order to increase the compressive strength, corrugated pipes with corrugated ring or spiral on the outer surface are widely used, and resin made with rubber packing is used. It is generally known that it is made by embedding what is connected by a joint. In this case, there are problems that the structure of the joint is complicated, that construction is troublesome, sufficient waterproofness cannot be obtained, and that flexibility is insufficient.

As an improved version of earthquake resistance and flexibility,
It is known to use a heat-shrinkable tube made by mixing polyethylene with EPDM, but rubber elasticity is insufficient,
There are problems that the shrinkage temperature is high and the construction is time-consuming, and that it cannot be used for PVC pipes that have a lower melting point than polyethylene.

[0014] A spiral made of resin is used to expand the vulcanized rubber to prevent spontaneous contraction during storage, as it can be used for polyvinyl chloride pipes that have a high melting point and can be installed in a short time and have a low melting point. It is possible to use a cold-shrinkable tube with a core inserted, but this product has problems that the structure is complicated and the product cost is high, and that the spiral core that removes the pipe at the time of joining is generated as waste.

In the case of sewer pipes, a plurality of resin adapters are adhered with an adhesive when joining a main pipe and a small-diameter home pipe or when performing a curved construction, but many materials are required. However, there is a problem that it is troublesome to construct.

[0016]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an object of the present invention is to process easily, to reduce natural shrinkage during product storage, and to use not only straight pipes but also elbows and different diameter pipes. A heat-shrinkable pipe joint made of a thermoplastic elastomer, which is easy to bond, can shrink at 50 to 120 ° C, and has excellent mechanical strength, weather resistance, chemical resistance, heat resistance and rubber elasticity after shrinking. Especially.

[0017]

It is an object of the present invention to solve the problems associated with the prior art as described above, and the material and shape of the pipes to be joined can be selected without any special adhesive such as adhesive or rubber ring. A heat-shrinkable pipe joint that does not require a sealant, can be easily joined in a short time, and has sufficient airtightness, flexibility, mechanical strength, weather resistance after joining, and is recyclable. It is to provide a pipe joint using a heat-shrinkable pipe joint.

[0018]

The present invention is a heat-shrinkable pipe joint and a pipe joint portion using the heat-shrinkable pipe joint as described below. (1) 100% tensile stress 1.0MPa to 4.5MP
a, a heat-shrinkable pipe joint formed by using a thermoplastic elastomer having an elongation of 200% to 1000%, in which the pipe joint length (Le), the pipe joint inner diameter (De), and the pipe joint are in a free state. Inner diameter after shrinkage (Do), wall thickness after shrinkage (to), outer diameter of pipe to be joined (Dp), thickness of pipe to be joined (t)
A heat-shrinkable pipe joint in which the relationship of p) satisfies the following expressions (1) to (4).

[0019]       1 <(De) / (Dp) ... (1)       1.20 ≦ (Dp) / (Do) ≦ 2.50 (2)       0.35 ≦ (Le) / (Dp) ≦ 3.0 (3)       1.0 ≦ (to) / (tp) ≦ 4.0 (4)

(2) The heat shrinkage temperature of the pipe joint is 50 to 1
The heat-shrinkable pipe joint according to (1) above, which has a heat-shrinkage rate of 20% to 75% at 20 ° C.

(3) The pipe joint comprises a crosslinked granular rubber (A) having an average particle size of 30 μm or less and a Vicat softening point 121.
-180 ° C thermoplastic resin (B) and melting point 50-120 ° C
(1), which is a thermoplastic elastomer containing the thermoplastic resin (C) and the softening agent (D).
The heat-shrinkable pipe joint according to (2).

(4) The crosslinked granular rubber (A) of the pipe joint is an ethylene / α-olefin copolymer rubber composed of ethylene and an α-olefin having 3 to 20 carbon atoms, or ethylene and carbon atoms. Ethylene / α-consisting of α-olefin of number 3 to 20 and non-conjugated polyene
Olefin / non-conjugated polyene copolymer rubber with a weight ratio of granular rubber (A) / olefin resin (B) of 90/10
50/50 (both total 100 parts by weight), (A)
And a melting point of 50 to 120 relative to 100 parts by weight of (B).
The heat-shrinkable pipe joint according to (1) to (3) above, which contains the resin (C) at 5 ° C. in an amount of 5 to 70 parts by weight and the softening agent (D) in an amount of 5 to 100 parts by weight.

(5) Vicat softening point 121 of the pipe joint
To 180 ° C. thermoplastic resin (B) is a crystalline high molecular weight solid resin obtained from the polymerization of one or more mono-olefins by either a high pressure method or a low pressure method. The heat-shrinkable pipe joint according to (1) to (4).

(6) The thermoplastic resin (C) having a melting point of 50 to 120 ° C. of the pipe joint is a copolymer composed of two or more kinds of α-olefins selected from α-olefins having 2 to 12 carbon atoms. The heat-shrinkable pipe joint according to any one of (1) to (5) above.

(7) A pipe joint comprising the heat-shrinkable pipe joint according to any one of (1) to (6) and a pipe to be joined having an outer diameter (Dp) and a wall thickness (tp). .

(8) A pipe joint portion in which a pipe having an outer surface having a flat shape, a spiral shape, or a ring shape is joined using the heat-shrinkable pipe joint according to any one of claims 1 to 6.

The pipe joint having the above-mentioned characteristics is a heat-shrinkable pipe joint having a 100% tensile stress of 1.0 MPa.
It is a heat-shrinkable pipe joint formed by using a thermoplastic elastomer having 4.5 MPa from a and an elongation of 200% to 1000%, and the ratio of the inner diameter (De) of the pipe joint to the outer diameter (Dp) of the pipe to be joined [Dp]. (De) / (Dp)] is greater than 1 and the ratio [(Dp) / (Do)] of the outer diameter (Dp) of the pipe to be joined and the inner diameter (Do) after shrinkage when the pipe joint is thermally shrunk in the free state ] Is 1.2
0 to 2.50, and the ratio [(Le) / (Dp)] of the pipe joint length (Le) to the pipe outer diameter (Dp) is 0.35 to
3.0, wall thickness after shrinkage of pipe joint (to) and wall thickness of pipe to be joined (t)
The ratio [(to) / (tp)] of p) is 1.0 to 4.0, the heat shrink temperature is 50 to 120 ° C., and the heat shrink ratio is 20% to 75%.

The heat-shrinkable pipe joint having the above-mentioned characteristics includes a crosslinked granular rubber (A) having an average particle diameter of 30 μm or less and a thermoplastic resin (B) having a Vicat softening point of 121 to 180 ° C. It is desirable that the thermoplastic elastomer comprises a thermoplastic resin (C) having a melting point of 50 to 120 ° C., and a softening agent (D).

The heat-shrinkable pipe joint according to the present invention as described above is expanded at a temperature below the Vicat softening point of the thermoplastic resin (B) and above the melting point of the thermoplastic resin (C).
It is a molded product obtained by cooling to a temperature below the melting point.

The heat-shrinkable pipe joint according to the present invention has specific tensile stress, elongation, shrinkage temperature, heat shrinkage rate and dimensions. (i) The 100% tensile stress of the thermoplastic elastomer used is 1.0 MPa to 4.5 MPa, preferably 1.5
MPa to 4.0 MPa (ii) The elongation of the thermoplastic elastomer used is 200%
To 1000%, preferably 250% to 900% (iii) shrinkable pipe joint inner diameter (De) and jointed pipe outer diameter (D)
The ratio (De) / (Dp) of p) is greater than 1, preferably 1.01 to 2.0, more preferably 1.05 to 1.8 (iv) the outer diameter (Dp) of the pipe to be joined, and the heat Ratio of inner diameter (Do) after heat shrinkage (D) when shrinkable pipe joint is heat shrunk in free state
p) / (Do) is 1.20 to 2.50, preferably 1.
More preferably from 25 to 2.30, the ratio [(Le) / (Dp)] of the pipe joint length (Le) to the pipe outer diameter (Dp) of 1.30 to 2.00 (v) is 0. 35 to 3.0, preferably 0.40 to 2.5 (vi) Thickness after contraction of pipe joint (to) and wall thickness of pipe to be joined (t)
p) ratio [(to) / (tp)] is 1.0 to 4.0, preferably 1.5 to 3.5 (vii) Shrinkage temperature is 50 to 120 ° C., preferably 60 to
The temperature is 110 ° C, more preferably 60 to 100 ° C. The heat shrinkage is 20% to 75%, preferably 25% to 70%.

100% of the thermoplastic elastomer used
Tensile stress and elongation are measured as follows.

The thermoplastic elastomer composition is heated to a molten state in a mold at a temperature above its melting point (190 ° C. when the resin B is polypropylene) using a press molding machine, and then 4
20 minutes × 20 cm × pressing for 5 minutes, then moving the mold together to a cooling press, cooling the mold for 5 minutes while water cooling the pressure plate.
Adjust a 2 mm press sheet. From this sheet JI
The No. 3 dumbbell test described in SK6251 is punched out and measured by the method described in the same method.

When it is necessary to use the product, the test piece is left in an oven at 120 ° C. for 20 minutes before punching to remove the stretch, and then allowed to stand at room temperature overnight.

The heat shrinkage rate and shrinkage temperature of the heat shrinkable pipe joint are
Measure as follows.

(1) Heat Shrinkage In the direction perpendicular to the pipe axis of the heat shrinkable pipe joint, JIS K625
A No. 3 dumbbell test piece described in 1 was punched out, and then a 20 mm marked line was drawn in the center of this test piece, and the temperature was 50 ° C or higher and 120
After leaving it for 10 minutes in an oven set to an arbitrary temperature of not higher than 0 ° C. by a method that does not prevent shrinkage, it is taken out from the oven and left to stand on a flat and flat surface for 1 hour at room temperature. Thereafter, the distance between the marked lines (L1, unit is mm) is measured, and the heat shrinkage rate at each arbitrary temperature is measured by the following formula (1).

Next, a temperature-shrinkage curve is created from the obtained shrinkage at any temperature, and the value when the shrinkage is in an equilibrium state (point C in FIG. 1) is shown for the heat-shrinkable pipe joint. The heat shrinkage rate. If the No. 3 dumbbell test piece cannot be punched through, use a test piece with an approximate shape.

Thermal shrinkage = [(20−L1) / 20] × 100 (%) (1) (2) Temperature at which the shrinkage obtained in the thermal shrinkage temperature (1) is in an equilibrium state. (Point D in FIG. 1) is the shrinkage temperature. Inner diameter (De) of heat-shrinkable pipe joint, outer diameter (Dp) of pipe to be joined, inner diameter after heat shrinkage (Do) when heat-shrinkable pipe joint is heat-shrinked in a free state,
The length (Le) of the pipe joint, the post-shrinkage wall thickness (to) of the pipe joint, and the wall thickness (tp) of the pipe to be joined are determined as follows. (3) Heat shrinkable pipe joint inner diameter (De) When the pipe is circular, the inner diameter is measured. When the pipe is elliptical, the average value of the inner minor diameter and the inner major diameter is measured. π
Converted according to. (4) Outer diameter of pipe to be joined (Dp) The outer diameter when the pipe is circular and the surface is flat, the outermost diameter when the pipe is circular and has irregularities such as spiral shape, ring shape, and the elliptical surface. If is smooth, the average value of the minor axis and the major axis is measured.If the pipe is irregular, the outermost circumference is measured and calculated.
Convert to the outer diameter of the circle by the same method as (3). (5) Inner diameter (Do) after heat shrinking when the heat shrinkable pipe joint is heat shrunk in a free state (Do) Heat shrink until the shrinkage reaches an equilibrium state at the shrink temperature without applying tension to the heat shrinkable pipe joint. After that, the inner diameter is measured by the same method as the above (3). (6) Length of pipe joint (Le) Measure and obtain the length in the pipe axis direction. If the cross section of the pipe is not flat or is not perpendicular to the pipe axis, measure the minimum value of the length in the pipe axis direction. (7) Wall thickness after shrinkage of pipe joint (to) After shrinking in the same manner as in (5), the wall thickness is measured and obtained as an average value.

(6) Wall thickness of pipe to be joined (tp) When the pipe shape is flat, the wall thickness in the circumferential direction is measured, and in the case of a spiral or ring shape, the wall thickness in the circumferential direction of the valley is measured. Calculate as the average value.

The thermoplastic elastomer forming the heat-shrinkable pipe joint according to the present invention has a specific 100% tensile stress, elongation and heat shrinkage. 100% tensile stress is 1 MPa
When the pressure is in the range from 4.5 MPa to 4.5 MPa, the wall thickness of the joint can be selected over a wide range and good watertightness can be obtained. When the elongation is in the range of 200% to 1000%, the diameter expansion for imparting heat shrinkability can be easily performed with a wide diameter expansion ratio, and the elbow and the different diameter pipe of the small diameter pipe and the large diameter pipe can be performed. A joint for coupling can be easily obtained.

The length (Le) of the pipe joint, the inner diameter (De) of the pipe joint, the inner diameter after contraction (Do) when the pipe joint is thermally contracted in the free state, the wall thickness after contraction (to), When the outer diameter (Dp) of the joint pipe and the wall thickness (tp) of the joint pipe satisfy the prescribed relationships, a pipe joint having sufficient strength, watertightness and excellent workability can be produced at low cost.

In the heat shrinkable pipe joint according to the present invention, the heat shrinkage temperature is preferably 50 to 120 ° C. When the heat shrinkage temperature is in the range of 50 to 120 ° C, it can shrink at a lower temperature than conventional products and can be applied to resin pipes with a low melting point such as polyvinyl chloride pipes and low density polyethylene pipes, and most resins can be used. It can be used for pipes. In addition, the effect of reducing the amount of heat for heating makes it possible to reduce the size of the heat-shrinking device and significantly reduce the construction time. Furthermore, there is little natural shrinkage during storage, and construction problems can be prevented.

In the heat shrinkable pipe joint according to the present invention, the heat shrinkage rate is preferably 20% to 75%.
When the heat shrinkage is in the range of 20% to 75%, not only good workability and sufficient watertightness can be obtained, but also when used in a spiral or ring-shaped pipe, the joint fits well in the groove and is strong. Can be combined easily. In the range of 75% or more, it is necessary to set the diameter expansion ratio to 300% (4 times the inner diameter of the original tube) or more, and the tube is frequently cut during the diameter expansion, which makes production difficult.

As the raw material rubber of the crosslinked granular rubber (A) used in the present invention, rubber which can be crosslinked by a known method can be used without limitation, but ethylene.α-
An olefin copolymer rubber or an ethylene / α-olefin / non-conjugated polyene copolymer rubber is preferable, and an ethylene / α-olefin / non-conjugated polyene copolymer rubber is particularly preferable.

As an α-olefin for producing an ethylene / α-olefin copolymer rubber or an ethylene / α-olefin / non-conjugated polyene copolymer rubber used as a raw material rubber for the crosslinked granular rubber (A) Has 3 to 20 carbon atoms, preferably 3 to 10 carbon atoms. Specific examples include propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene and the like. Of these, propylene and 1-butene are preferred. That is,
As a raw material for the crosslinked granular rubber (A), ethylene.
Propylene / non-conjugated polyene copolymer rubber, ethylene /
A 1-butene / non-conjugated polyene copolymer rubber is preferable, and an ethylene / propylene / non-conjugated polyene copolymer rubber is particularly preferably used.

Ethylene / α-olefin copolymer rubber used as a raw material rubber for the crosslinked granular rubber (A),
To ethylene / α-olefin / non-conjugated polyene copolymer rubber has a molar ratio (ethylene / α-olefin) of structural units derived from ethylene and α-olefin of 55/4.
It is desirable to be in the range of 5 to 85/15, preferably 60/40 to 80/20.

As the non-conjugated polyene for producing the ethylene / α-olefin / non-conjugated polyene copolymer rubber used as the raw material rubber for the crosslinked granular rubber (A), a cyclic or chain-like non-conjugated polyene is used. Used.
Examples of the cyclic non-conjugated polyene include 5-ethylidene-2
-Norbornene, dicyclopentadiene, 5-vinyl-2-norbornene, norbornadiene, methyltetrahydroindene and the like can be mentioned. Further, as the chain-like non-conjugated polyene, for example, 1,4-hexadiene, 7-methyl-1,6-
Octadiene, 8-methyl-4-ethylidene-1,7-nonadiene, 4-ethylidene-1,7-undecadiene and the like can be mentioned. These non-conjugated polyenes are used alone or as a mixture of two or more thereof, and the copolymerization amount thereof is 1 in iodine value.
-40, preferably 2-35, more preferably 3-30
Is desirable.

The intrinsic viscosity [η] of ethylene / α-olefin / non-conjugated polyene copolymer rubber used as a raw material rubber for the crosslinked granular rubber (A) measured in decalin (decahydromaphthalene) at 135 ° C. is , 0.8 to 6.0
dl / g, preferably 1.0-. It is desirable to be in the range of 5.0 dl / g, and more preferably 1.1 to 4.0 dl / g.

Ethylene / α-having the above characteristics
The olefin copolymer rubber or the ethylene / α-olefin / non-conjugated polyene copolymer rubber is known in the art as described in “Polymer Production Process (published by Industrial Research Institute)”, pages 309 to 330, etc. It can be prepared by the method of.

As the raw material rubber for the crosslinked granular rubber (A), a polymer other than the ethylene / α-olefin copolymer rubber or the ethylene / α-olefin / non-conjugated polyene copolymer may be used. For example, natural rubber, styrene butadiene rubber, nitrile rubber, chloroprene rubber, acrylic rubber, hydrogenated NBR and the like can be mentioned. These can be used alone or in combination of two or more, and ethylene.α
-Can be used in combination with olefin / non-conjugated polyene copolymer rubber.

As a method for uniformly dispersing the particles of the crosslinked granular rubber (A), for example, a non-crosslinked ethylene / α-olefin / nonconjugated polyene copolymer which is a raw material rubber of the crosslinked granular rubber (A) is used. Coalescence and Vicat softening point 121
The olefin resin (B) at ~ 180 ° C, the cross-linking agent, and other compounding agents are kneaded by a twin-screw extruder, a Banbury mixer, etc., and ethylene / α-olefin / A method of dynamically crosslinking so that the average particle diameter of the non-conjugated polyene copolymer rubber is 30 μm or less, and a non-crosslinked ethylene / α-olefin / nonconjugated polyene copolymer which is a raw material rubber of the crosslinked granular rubber (A). The polymer is mixed with a cross-linking agent and other compounding agents and then cross-linked, and the cross-linked product is pulverized to have an average particle size of 30 μm or less, and then the particles are subjected to a Vicat softening point of 121 by a twin-screw extruder, a Banbury mixer or the like. ~ 180 ° C olefin resin (B)
And a method of kneading with the resin (C) having a melting point of 50 to 120 ° C. Of course, the method for manufacturing the heat-shrinkable pipe joint of the present invention is not limited to the above method.

The average particle size of the crosslinked granular rubber (A) is 30 μm or less, preferably 20 μm or less, more preferably 10 μm or less in order to maintain good surface smoothness and mechanical strength of the heat-shrinkable pipe joint. Desirable for.

The olefinic resin (B) used in the present invention has a Vicat softening point of 121 to 180 ° C., preferably 125 to 165 ° C., and high crystallinity obtained from the polymerization of one or more monoolefins. Molecular weight solid resin, MFR (ASTM D1238-65T, 230
(° C) is usually 0.01 to 100 g / 10 min, especially 0.05
It is preferably in the range of up to 70 g / 10 minutes. The crystalline polyolefin resin has a role of improving fluidity and mechanical strength of the composition, and typical examples thereof include polyethylene and polypropylene, but polypropylene is particularly preferable.

The resin (C) having a melting point of 50 to 120 ° C. used in the present invention is a homopolymer or copolymer of α-olefin, polystyrene, ABS resin, polyvinyl chloride resin,
Examples thereof include syndiotactic 1,2-polybutadiene.

The polymerization method of the olefin resin used as the resin (C) in the present invention may be either random polymerization or block polymerization. In the case of a random polymer, the smaller α
An α-olefin copolymer containing an olefin constituent unit in an amount of usually 40 mol% or less, preferably 30 mol% or less is desirable.

The α-olefin has 2 to 12 carbon atoms,
For example, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1pentene, 1-octene, 1-decene and the like can be mentioned. Of these, ethylene, propylene, 1-butene, 1-octene and the like are preferable.

The homopolymer is preferably an ethylene or 1-butene homopolymer, and the α-olefin copolymer is an α-olefin having 2 to 12 carbon atoms, preferably 2 to 10 carbon atoms.
-Α-olefin copolymers obtained by copolymerizing two or more α-olefins selected from olefins are preferable, copolymers of ethylene and α-olefins having 3 to 10 carbon atoms, and propylene and 2 to 10 carbon atoms. Are preferable, and copolymers of 1-butene and α-olefins having 2 to 10 carbon atoms, particularly crystalline α-olefin copolymers are preferable.

In the case of polystyrene, a homopolymer of styrene or a copolymer of styrene and acrylonitrile, methyl methacrylate, α-methylstyrene or the like is preferable.

In the case of ABS resin, 20 to 35 mol% of acrylonitrile constitutional unit and 20 parts of butadiene constitutional unit are used.
ABS resins containing -30 mol% and styrene constitutional units of 40-60 mol% are preferred.

The resin (C) used in the present invention is
Those having a melting point of 50 to 120 ° C., preferably 60 to 115 ° C. can be used without limitation. Since the resin (C) having a melting point of 50 to 120 ° C. is used, it is possible to obtain a heat-shrinkable pipe joint that can recover the shape at a low temperature in a short time and has a small natural recovery during storage.

In the heat shrinkable pipe joint of the present invention, the weight ratio of the crosslinked granular rubber (A) to the olefin resin (B) is 90/10 to 50/50, preferably 85/15 to 5.
It is preferably 5/45, more preferably 80/20 to 60/40 (both total 100 parts by weight). Since the weight ratio of the crosslinked granular rubber (A) and the olefin resin (B) is in the above ratio, it is possible to obtain a heat-shrinkable pipe joint excellent in moldability, flexibility and rubber elasticity.

The heat-shrinkable pipe joint of the present invention has a melting point of 5
The content of the resin (C) at 0 to 120 ° C. is the total amount of the crosslinked granular rubber (A) and the olefin resin (B) of 10
5 to 70 parts by weight, preferably 10 to 60 parts by weight, relative to 0 parts by weight
It is desirable that the amount is parts by weight, more preferably 10 to 50 parts by weight. Since the content of the resin (C) is in the above range, it is possible to obtain a heat-shrinkable pipe joint which prevents natural recovery during storage, has excellent rubber elasticity and recovery rate, and has a small permanent set.

The content of the softening agent (D) in the heat-shrinkable pipe joint of the present invention is 5 to 10 based on 100 parts by weight of the total amount of the crosslinked granular rubber (A) and the olefin resin (B).
It is desirable that the amount is 0 parts by weight, preferably 10 to 90 parts by weight.

Examples of the softener (D) of the present invention include petroleum-based softeners such as process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, and petrolatum.
Coal tar, coal tar softeners such as coal tar pitch, castor oil, rapeseed oil, soybean oil, fatty oil softeners such as coconut oil, tall oil, beeswax, carnauba wax, waxes such as lanolin, ricinoleic acid, Fatty acids such as palmitic acid, stearic acid, barium stearate, calcium stearate or metal salts thereof, naphthenic acid or metal soaps thereof, pine oil, rosin or its derivatives, terpene resins, petroleum resins, coumarone indene resins, atactic polypropylene, etc. Synthetic polymeric substances, dioctyl phthalate, dioctyl adipate, ester plasticizers such as dioctyl sebacate, carbonate ester plasticizers such as diisododecyl carbonate, other microcrystalline wax, sub (factice), liquid polybutadiene,
Examples include modified liquid polybutadiene, liquid thiocol, and hydrocarbon-based synthetic lubricating oil. Of these, petroleum-based softeners and hydrocarbon-based synthetic lubricating oils are preferable.

Examples of the cross-linking agent used in the production of the cross-linked granular rubber (A) of the present invention include organic peroxides, sulfur compounds, and those commonly used in the rubber industry. You can Organic peroxides include dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, 2,5 -Dimethyl-2,5-di (t-
Butylperoxy) hexyne-3, di-t-butylperoxide, di-t-butylperoxy-3,3,5-trimethylcyclohexane, t-dibutylhydroperoxide and the like. Among them, dicumyl peroxide, di-t-butyl peroxide and di-t-butylperoxy-3,3,5-trimethylcyclohexane are preferably used.

The amount of the organic peroxide is usually 1 per 100 g of the raw rubber used as the crosslinked granular rubber (A).
× 10 ^{-3 to} 5 × 10 ^-2 mol, preferably 3 × 10 ^-3 to
3 × 10 ^- used in ² molar ratio.

When an organic peroxide is used as a crosslinking agent, it is preferable to use a crosslinking auxiliary together. Examples of the crosslinking aid include sulfur; quinonedioxime compounds such as p-quinonedioxime; (meth) acrylic compounds such as ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate; diallyl phthalate, triallyl isocyanurate, etc. Allyl compounds; other maleimide compounds, divinylbenzene and the like.

Such a cross-linking aid is used in a proportion of 0.5 to 2 mol, preferably equimolar to 1 mol of the organic peroxide used.

Examples of the sulfur compounds include sulfur, sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, tetramethylthiuram disulfide and selenium dithiocarbamate. Of these, sulfur is preferred.

The sulfur compound is usually 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, and more preferably 1. to 100 parts by weight of the rubber used as the crosslinked granular rubber (A). It is used in a proportion of 0 to 3.0 parts by weight.

When a sulfur compound is used as a crosslinking agent, it is preferable to use a vulcanization accelerator together. As the vulcanization accelerator, for example, N-cyclohexyl-2-benzothiazole sulfenamide, N-oxydiethylene-2-benzothiazole sulfenamide, N, N'-diisopropyl-2-benzothiazole sulfenamide, 2 -Thiazol compounds such as mercaptobenzothiazole, 2- (2,4-dinitrophenyl) mercaptobenzothiazole, 2- (2,6-diethyl-4-morpholinothio) benzothiazole and dibenzothiazyl-disulfide; diphenylguanidine , Guanidine compounds such as triphenylguanidine and diorsotolyl guanidine; aldehyde amine compounds such as acetaldehyde-aniline condensate and butyraldehyde-aniline condensate; imidazoline compounds such as 2-mercaptoimidazoline; diethylthiourea, dibutylthiourea etc. Thiourea system Compounds; thiuram-based compounds such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide; zinc dimethyldithiocarbamate;
Examples thereof include dithioate-based compounds such as zinc diethyldithiocarbamate and tellurium diethyldithiocarbamate; xanthate-based compounds such as zinc dibutylxanthate; and zinc oxide.

These vulcanization accelerators are added to 100 parts by weight of the raw rubber used as the crosslinked granular rubber (A).
0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight,
It is more preferably used in a proportion of 0.5 to 5 parts by weight.

As the components of the heat-shrinkable pipe joint according to the present invention, the granular rubber (A) cross-linked with the above-mentioned crosslinking agent, crosslinking aid, vulcanizing agent and vulcanization accelerator and the Vicat softening point 121 to In addition to the olefin resin (B) having a temperature of 180 ° C., the resin (C) having a melting point of 50 to 120 ° C., and a softening agent, if necessary, other conventionally known compounding agents such as a reinforcing agent, a filler, a processing aid, a pigment, Compounding agents which are usually used in the production of rubbers and thermoplastic resins such as anti-aging agents and foaming agents are used within the range not impairing the object of the present invention.

Examples of the reinforcing agent include SRF and G
PF, FEF, MAF, ISAF, SAF, FT, MT
Various carbon blacks such as, and finely divided silicic acid are appropriately used.

As the filler, for example, light calcium carbonate, heavy calcium carbonate, talc, clay and the like are used.

These reinforcing agents and fillers are the total amount of the crosslinked granular rubber (A), the olefin resin (B) having a Vicat softening point of 121 to 180 ° C., and the resin (C) having a melting point of 50 to 120 ° C. of 100. 100 parts by weight or less with respect to parts by weight,
It is preferably used in a proportion of 80 parts by weight or less.

As the processing aid, it is possible to use a processing aid which is usually used for processing rubber or thermoplastic resin. Examples of such processing aids include higher fatty acids such as ricinoleic acid, stearic acid, palmitic acid, and lauric acid; higher fatty acid salts such as barium stearate, calcium stearate, and zinc stearate; ricinoleic acid ester, stearic acid ester, Examples thereof include higher fatty acid esters such as palmitic acid ester and lauric acid ester.

The processing aid is usually 100 parts by weight in total of a crosslinked granular rubber (A), an olefin resin (B) having a Vicat softening point of 121 to 180 ° C. and a resin (C) having a melting point of 50 to 120 ° C. On the other hand, it is desirable to use it in an amount of about 10 parts by weight or less, preferably about 0.5 to 5 parts by weight.

As the pigment, conventionally known inorganic pigments (eg titanium white) and organic pigments (eg naphthol green B) are used. The pigment includes a crosslinked granular rubber (A), an olefin resin (B) having a Vicat softening point of 121 to 180 ° C, and a resin (C) having a melting point of 50 to 120 ° C.
50 parts by weight, preferably 40 parts by weight, based on 100 parts by weight in total.

Examples of the antiaging agent include aromatic secondary amine stabilizers such as phenylbutylamine, N, N'-di-2-naphthyl-p-phenylenediamine, dibutylhydroxytoluene, tetrakis [methylene (3 , 5-Di-t-butyl-4-hydroxy) hydrocinnamate] Phenolic stabilizers such as methane, bis [2-methyl-4- (3-n-alkylthiopropionyloxy) -5-t-butylphenyl] Examples thereof include thioether-based stabilizers such as sulfides and dithiocarbamate-based stabilizers such as nickel dibutyldithiocarbamate.

The antioxidants can be used alone or in combination of two or more. Such an anti-aging agent includes cross-linked granular rubber (A) and Vicat softening point 121.
-180 ° C olefin resin (B) and melting point 50-12
It is usually used in an amount of 0.1 to 5 parts by weight, preferably 0.2 to 3 parts by weight, based on 100 parts by weight of the total amount of the resin (C) at 0 ° C.

The heat-shrinkable pipe joint according to the present invention exhibits excellent heat resistance and durability without the use of an antiaging agent. However, if an antiaging agent is further used, the product life will be extended. It is possible to

The heat-shrinkable pipe joint according to the present invention may be a non-foamed body or a foamed body. As the foaming agent used for forming the foam, any of physical foaming agents such as supercritical carbon dioxide and water and commercially available chemical foaming agents can be preferably used. As a chemical foaming agent,
For example, inorganic foaming agents such as sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate and ammonium nitrite; nitroso compounds such as N, N'-dinitrosoterephthalamide and N, N'-dinitrosopentamethylenetetramine, Azo compounds such as azodicarbonamide, azobisisobutyronitrile, azocyclohexylnitrile, azodiaminobenzene, barium azodicarboxylate, benzenesulfonyl hydrazide, toluenesulfonyl hydrazide, p, p'-oxybis (benzenesulfonylhydrazide) diphenyl Sulphone-3,3'-
Examples thereof include sulfonyl hydrazide compounds such as disulphenyl hydrazide, azide compounds such as calcium azide, 4,4′-diphenyl disulfonyl azide, and paratoluene sulfonyl azide. Among them, an azo compound, a sulfonyl hydrazide compound, and an azide compound are preferably used.

The blending amount of the foaming agent is appropriately selected so that the specific gravity of the foamed body after vulcanization and foaming is 0.01 to 0.8. However, the crosslinked granular rubber (A) and the Vicat softening point 121 to 18
0.5 to 40 parts by weight, preferably 1 to 30 parts by weight, and more preferably 2 to 100 parts by weight of the total amount of 0 ° C. olefin resin (B) and melting point 50 to 120 ° C. resin (C).
It is desirable to use 25 parts by weight.

If necessary, a foaming aid may be used in combination with the foaming agent. The addition of the foaming aid is effective in controlling the decomposition temperature of the foaming agent and making the bubbles uniform.
Examples of the foaming aid include organic acids such as salicylic acid, phthalic acid, stearic acid and oxalic acid, urea and derivatives thereof.

[Preparation of Heat Shrinkable Pipe Joint] The heat shrinkable pipe joint according to the present invention can be prepared, for example, by the following method. That is, for example, a non-crosslinked ethylene / α-olefin / non-conjugated polyene copolymer rubber used as a crosslinked granular rubber (A) which is an essential component of the heat-shrinkable pipe joint according to the present invention, and a Vicat softening point. 121 ~ 1
The olefin resin (B) at 80 ° C., the softening agent (D), a cross-linking agent, and other compounding agents are kneaded by a twin-screw extruder, a Banbury mixer, or the like at a temperature not lower than the melting point of the olefin resin (B), and the device is used. Under high shear, in medium or other kneader,
Crosslinking agent Dynamically crosslinked above the reaction temperature, ethylene / α-olefin / non-conjugated polyene copolymer rubber has an average particle size of 3
The crosslinked granular rubber (A) having a particle size of 0 μm or less is kneaded so as to be a composition uniformly dispersed in the olefin resin (B). It is preferable that the softening agent is preliminarily oil-extended in the non-crosslinked ethylene / α-olefin / non-conjugated polyene copolymer rubber because the kneading property is improved.

Then, the composition is melted at a melting point of 50 to 120 ° C.
The resin (C) and the softening agent and the like as necessary are kneaded by a twin-screw extruder, a Banbury mixer or the like and pelletized by a pelletizer to prepare a pellet-shaped thermoplastic elastomer for a heat-shrinkable pipe joint. Of course, the method for producing the thermoplastic elastomer used in the present invention is not limited to the above method.

The thermoplastic elastomer for the heat-shrinkable pipe joint thus prepared is heated to a temperature not lower than the melting point of the olefin resin (B) by an extruder, calender roll, press, injection molding machine, transfer molding machine or the like. It is molded into a desired shape at a temperature and becomes a heat-shrinkable pipe joint molded body.

The heat-shrinkable pipe joint molded article is a molded article obtained from the above-mentioned thermoplastic elastomer, and the heat shrinkability can be imparted by the following method. First, the heat-shrinkable pipe joint molded body is expanded or stretched at a temperature not higher than the Vicat softening point of the olefin resin (B). For example, a molded body of a tube, a sheet or a rod is heated from room temperature to 120 ° C.
The diameter expansion or stretching is performed at a temperature of less than. Next, in an expanded or stretched state, in a temperature atmosphere not lower than the melting point of the resin (C) and lower than the Vicat softening point of the olefin resin (B), preferably the melting point of the resin (C) + 10 ° C. or higher, the olefin resin (B The Vicat softening point of 1) is kept below −10 ° C. for 1 to 60 minutes, preferably 3 to 40 minutes, and then cooled to below the melting point of the resin (C) in the expanded or stretched state. There are no particular restrictions on the cooling method, such as cooling by cooling, water cooling, or air cooling.

The heat-shrinkable pipe joint of the present invention obtained as described above retains its expanded or stretched shape even if the force applied for expanding or stretching is removed.

When the heat-shrinkable pipe joint of the present invention obtained as described above is placed again in an atmosphere of a temperature equal to or higher than the melting point of the resin (C), molding for heat-shrinkable pipe joint before expansion or stretching is performed. It tries to return to the body and heat shrinks. The heat-shrinkable pipe joint according to the present invention is, for example, a tubular elastomer molded body having a large inner diameter after expansion, and a shape before expansion of the tubular elastomer molded body having a smaller diameter than this inner diameter.
It is possible to repeat the contraction and expansion of the tubular elastomer molded body.

The reason why the heat-shrinkable pipe joint having such an effect can be provided is not clear, but it is presumed as follows. That is, the resin (C) having a melting point of 50 to 120 ° C. is contained in the olefin resin component in the thermoplastic elastomer composed of the crosslinked granular rubber (A) and the olefin resin (B) having a Vicat softening point of 121 to 180 ° C. When the thermoplastic elastomer is expanded or stretched at a temperature below the Vicat softening point of the olefin resin (B) and above the melting point of the resin (C), the resin (C) is stretched in the deformation direction in the form of fine particles. As it cools, it loses elasticity and this hinders rubber elasticity (shape recovery). At the time of shape recovery, resin (C)
Melts, the tension is released, and the original state is restored. The resin (C) that has returned to the original state acts as a filler in the heat-shrinkable pipe joint, so that the pipe joint after contraction exhibits high rubber elasticity at the operating temperature.

The heat-shrinkable pipe joint of the present invention comprises a crosslinked granular rubber (A) or a granular rubber (A) containing a softening agent.
Olefinic resin (B) having a Vicat softening point of 121 to 180 ° C and a melting point of 50 to 120 ° C (C), or olefinic resin (B) having a Vicat softening point of 121 to 180 ° C and a melting point of 50 to 120 ° C ( C) and a high-rubber-elastic thermoplastic elastomer finely dispersed in a softening agent (D) to control heat resistance with a Vicat softening point of 121 to 180 ° C.
Since the olefin resin and the heat shrinkage temperature are controlled by the resin (C) having a melting point of 50 to 120 ° C., it is easy to use and has high rubber elasticity comparable to vulcanized rubber.

The average particle diameter of the crosslinked granular rubber of the present invention, the melting point of the resin, and the Vicat softening point are values determined by the following methods. (1) Average Particle Size of Granular Rubber An electron microscope was used to take a photograph of a cross section of the thermoplastic elastomer composition magnified 5000 times, and the average particle size of the dispersed crosslinked rubber component was measured by image analysis.

(2) Melting Point of Resin (DSC Method) The melting point of the resin is measured by using DSC, after raising the temperature from room temperature to 200 ° C. and holding for 10 minutes, then cooling to −40 ° C. and then from −40 ° C. It was displayed at the apex of the endothermic peak when the temperature was raised to 200 ° C. The heating rate was 10 ° C./min.

(3) Vicat softening point Measured according to ASTM D1525.

Since the heat-shrinkable pipe joint of the present invention has the above-mentioned characteristics, it can be suitably used as a tube-, sheet-, or rod-shaped heat-shrinkable pipe joint.

The heat-shrinkable pipe joint of the present invention is used as a tube-, sheet-, or rod-shaped heat-shrinkable pipe joint, and has a flat-shaped, ring-shaped, spiral-shaped pipe joint, elbow, cheese or a different diameter. It can be widely used for pipe joints, etc.

[0098]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0099]

Example 1 As a raw material rubber for the crosslinked granular rubber (A), ethylene-propylene-5-ethylidene having an ethylene content of 78 mol%, an iodine value of 13 and an intrinsic viscosity [η] of 3.3 dl / g. -2-Norbornene copolymer rubber [EPT-1] 100 parts by weight, mineral oil softener (D)
(Idemitsu Kosan Dyna Process Oil PW-380) 75
175 parts by weight of EPT pellets blended with 1 part by weight, polypropylene pellets [PP-1: trade name Grand Polypro J101 (made by Grand Polymer), Vicat softening point 155 ° C.] as olefin resin (B) 45 parts by weight, and crosslinking agent 1 A mixed solution of 0.3 parts by weight of 3,3-bis (tert-butylperoxyisopropyl) benzene and 0.3 parts by weight of a crosslinking aid divinylbenzene was uniformly mixed in a Henschel mixer. Next, the pellets on which the cross-linking agent and the cross-linking aid are attached on the surface are extruded at 230 ° C. using a twin-screw extruder (Toshiba Kikai Co., Ltd. TEM-50), and a dynamic heat treatment is performed to obtain PP To obtain a composition in which the EPT crosslinked granular rubber (A) was uniformly dispersed. Next, based on 100 parts by weight of the total amount of (A) and (B) in this composition, an ethylene / 1-butene copolymer [E] as a resin (C) [E
BR-1: ethylene content 90 mol%, 1-butene content 10 mol%, melting point 82 ° C.] 20 parts by weight are extruded at 230 ° C. using the above-mentioned twin-screw extruder, passed through a pelletizer, and pelletized. A thermoplastic elastomer for heat-shrinkable pipe joints was obtained. The melt flow rate of this thermoplastic elastomer was measured according to ASTM-D-1238-65T at 230 ° C and 2.16.
It was measured under a load of kg. The composition was heated and pressed at 190 ° C. for 4 minutes with a press molding machine and then cooled for 5 minutes to obtain 200 mm × 2.
A sheet of 00 mm x 2 mm was prepared and the hardness was JISK6.
253, 100% tensile stress and elongation according to JIS K6251
Was measured by the method.

Further, the same pelletized thermoplastic elastomer was mixed with a single-screw extruder [P50-32A of Japan Steel Works Ltd.].
BV)] at 190 ° C. to obtain a tube having an inner diameter of 75 mm and a thickness of 3.5 mm. This tube was allowed to cool overnight at room temperature, and then two tubes each having a length of 200 mm were cut out to obtain a heat-shrinkable pipe joint molded body.

Two of these heat-shrinkable pipe joint molded bodies were preheated in an oven at 120 ° C. for 10 minutes, and then each had an outer diameter of 33.
Using a diameter expander consisting of two mm rollers, the diameter expansion ratio is 1
Stretched and expanded to 00% (twice the original inner diameter), then 1
Hold in an oven at 20 ° C for 10 minutes, then, while still attached to the expander, soak it in cold water at 4 ° C for 10 minutes to impart heat shrinkability, and then remove from the expander at room temperature for one day and night. After leaving it for 2 hours, it was cut into a length of 150 mm to obtain two heat-shrinkable pipe joints.

Using one of the heat-shrinkable pipe joints, the heat-shrinkage rate, the shrinkage temperature, the inner diameter (Do) after shrinkage of the heat-shrinkable pipe joint and the wall thickness after shrinkage of the heat-shrinkable pipe joint according to the method described above. (T
o) was measured. Inner diameter of one other heat-shrinkable pipe fitting (D
e) and the length (Le) of the heat-shrinkable pipe joint, the outer diameter (Dp) 117 mm and the wall thickness (tp) 1.8 of the pipe to be joined are measured.
mm, length of 200 mm, independent double-pressed pipes [(Dipolin DDM-100: manufactured by Torii Kasei Co., Ltd.) are used, and set so that the mating surface becomes the center of the heat-shrinkable pipe joint. For 5 minutes, the entire circumference was uniformly heated from the mating surface in the center toward both ends of the heat-shrinkable pipe joint, and heat-shrinked to join the pipes to be joined.

After adjusting the condition of the joined pipe joined by the heat-shrinkable pipe joint at room temperature for one day, a linear negative pressure test by negative pressure inside the pipe was carried out in accordance with JIS K6741.

[0104]

Example 2 An ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber (EPT) having an ethylene content of 63 mol%, an iodine value of 22 and an intrinsic viscosity [η] of 3.0 dl / g in Example 1 was used. -2) 100 parts by weight,
Mineral oil softener (Dyna Process Oil PW manufactured by Idemitsu Kosan
-380) Oil-extended EPT150 blended with 50 parts by weight
Parts by weight and 35 parts by weight of polypropylene (PP-1) in advance by an internal mixer [Kobe Steel Co., Ltd. Mixtron BB1
6] and used as a resin (C) in the form of pellets by mixing with an pulverizer and ethylene / 1-butene copolymer [EBR-2: ethylene content 85 mol%, 1-butene content 15 mol %, Melting point 59 ° C.] was used in the same manner as in Example 1 except that a heat-shrinkable pipe joint composition was prepared. The results are shown in Table 1.

[0105]

Example 3 In Example 1, as a raw material rubber for the crosslinked granular rubber (A), ethylene having an ethylene content of 78 mol%, an iodine value of 12, and an intrinsic viscosity [η] of 4.1 dl / g. 100 parts by weight of propylene / 5-ethylidene-2-norbornene copolymer rubber (EPT-3),
Oil-extended EP blended with 120 parts by weight of mineral oil-based softening agent (D) (Idemitsu Kosan Dyna Process Oil PW-380)
T220 parts by weight and P as the olefin resin (B)
The same procedure as in Example 1 was carried out except that 45 parts by weight of P-1 were mixed in advance with an internal mixer [Mixtron BB16 of Kobe Steel Ltd.] and pelletized with a pulverizer. The results are shown in Table 1.

[0106]

[Example 4] In Example 1, except that the heat shrinkable pipe joint molded body had an inner diameter of 60 mm and a diameter expansion ratio of 200%.
The same procedure as in Example 1 was performed. The results are shown in Table 1.

[0107]

[Example 5] The same procedure as in Example 1 was carried out except that the length of the heat-shrinkable pipe joint was changed to 60 mm. The results are shown in Table 1.

[0108]

Example 6 The procedure of Example 1 was repeated except that the thickness of the heat-shrinkable pipe joint molded article was changed to 2.0 mm. The results are shown in Table 1.

[0109]

Example 7 In Example 1, polypropylene pellets [PP-2: trade name Grand Polypro B241 (manufactured by Grand Polymer) as the olefin resin (B),
Vicat softening point 135 ° C.], 1-butene / ethylene copolymer as resin (C) [BER: 1-butene content 99
Mol%, ethylene content 1 mol%, melting point 112 ° C.] 5
Example 1 was repeated except that 0 part by weight was used. The results are shown in Table 1.

[0110]

[Embodiment 8] In Embodiment 1, as resin (C), 1-
Using butene-propylene copolymer [BPR: 1-butene content 75 mol%, propylene 25 mol%, melting point 71 ° C.], the pipe to be joined has an outer diameter (Dp) of 114 mm and a wall thickness of the pipe.
(tp) The same procedure as in Example 1 was performed except that two flat hard vinyl chloride pipes VU100 having a length of 3.1 mm and a length of 200 mm were used. The results are shown in Table 1.

[0111]

Comparative Example 1 In Example 1, 78 g of the granular rubber (A) was used.
Parts by weight, propylene / 1 as the olefin resin (B)
-Butene copolymer [PBR: propylene content 88 mol%, 1-butene content 12 mol%, Vicat softening point 11
4 ° C.] and the mineral oil-based softening agent (D) were used in an amount of 22 parts by weight and 90 parts by weight, respectively. The results are shown in Table 2. The 100% tensile stress, (Dp) / (Do) and the shrinkage rate were both low, sufficient tightening force could not be obtained, and the negative pressure could not be maintained for the specified time in the linear negative pressure test.

[0112]

Comparative Example 2 The procedure of Example 1 was repeated except that the resin (C) was not used. The results are shown in Table 2.
Since the resin (C) was not used, it contracted when it was removed from the diameter expansion device, and the resin tube could not be inserted.

[0113]

Comparative Example 3 The procedure of Example 1 was repeated, except that the heat-shrinkable pipe joint molding had an inner diameter of 106 mm. The results are shown in Table 2. (Dp) / (Do) was small, and the negative pressure could not be maintained for the specified time in the linear negative pressure test.

[0114]

Comparative Example 4 The procedure of Example 1 was repeated, except that the length (Le) of the heat-shrinkable pipe joint was changed to 35 mm. The results are shown in Table 2. (Le) / (Dp) was small, and the negative pressure could not be maintained for the specified time in the linear negative pressure test.

[0115]

COMPARATIVE EXAMPLE 5 The procedure of Example 1 was repeated except that the thickness (to) of the heat-shrinkable pipe joint was changed to 1.1 mm. The results are shown in Table 2. (To) / (tp) was small, and the negative pressure could not be maintained for the specified time in the linear negative pressure test.

[0116]

Comparative Example 6 In Example 1, the granular rubber (A) was mixed with 45
1 part of butene / ethylene copolymer [BER: 55 parts by weight of olefin resin (B), resin (C)]
Example 1 was repeated except that 1-butene content was 99 mol%, ethylene content was 1 mol%, melting point was 112 ° C, and 30 parts by weight of the mineral oil-based softening agent (D) was used. The results are shown in Table 2. Poor rubber elasticity, requiring high shrinkage temperature, 1
Since the 00% tensile stress was also high, the pipe to be joined was deformed. In addition, the adhesion after shrinkage was poor, and the negative pressure could not be maintained for the specified time in the linear negative pressure test.

[0117]

COMPARATIVE EXAMPLE 7 In Example 1, 70 parts by weight of the crosslinked granular rubber (A), 30 parts by weight of the olefin resin (B), 10 parts by weight of the resin (C), and a mineral oil softener (D )
The same procedure as in Example 1 was carried out except that the above was changed. The results are shown in Table 2. It could not be used as a joint because it was cut when expanding the diameter of the heat-shrinkable pipe joint.

[0118]

EFFECTS OF THE INVENTION The heat-shrinkable pipe joint of the present invention has excellent results in a linear negative pressure test.

[0119]

[Table 1]

[0120]

[Table 2]

[Brief description of drawings]

FIG. 1 is a temperature-shrinkage rate curve used when calculating a shrinkage temperature in the present invention.

[Fig. 2] Joining of flat-shaped pipes according to the present invention

FIG. 3 Joining of ring-shaped tubes according to the present invention

[Explanation of symbols]

2A, B Pipe to be joined, Figure 2C Butt surface Figure 2D Joint. Dotted line in Fig. 2 The dotted line is the joint before heat shrinkage. Figure 3A, B Pipe to be joined Figure 3C Butt surface Figure 3D fitting. Dotted line in Fig. 3 The dotted line is the joint before heat shrinkage.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3H019 FA01                 4F071 AA02 AA15X AA20 AA20X                       AA21X AA71 AA84 AA85                       AD06 AE04 AF02 AF13 AF45                       AH03 AH12 AH17 BA01 BB06                       BC05 BC12                 4J002 AC01W AC03Y AC05X AC08W                       AC11W AE00Y AE03Y AE04Y                       AE05Y AF02Y AG00Y BA01Y                       BB03X BB05W BB10W BB12X                       BB13Y BB16X BB19X BC03X                       BC06X BC07X BD04X BG04W                       BG06W BN15X EH006 EH096                       EH146

Claims (8)

[Claims] 1. A 100% tensile stress of 1.0 MPa to 4.
A heat-shrinkable pipe joint made of a thermoplastic elastomer having 5 MPa and an elongation of 200% to 1000%, the length of the pipe joint (Le), the inner diameter of the pipe joint (De), and the pipe joint in a free state. A heat-shrinkable tube in which the relationships among the inner diameter after shrinkage (Do), the wall thickness after shrinkage (to), the outer diameter of the pipe to be joined (Dp), and the wall thickness of the pipe to be joined (tp) satisfy the following four expressions Fittings. 1 <(De) / (Dp) 1.2 ≦ (Dp) / (Do) ≦ 2.5 0.35 ≦ (Le) / (Dp) ≦ 3.0 1.0 ≦ (to) / (tp) ≤ 4.0 2. The heat shrinkage temperature of the pipe joint is 50 to 120.
The heat-shrinkable pipe joint according to claim 1, wherein the heat-shrinkable pipe joint has a heat shrinkage rate of 20% to 75%. 3. The pipe fitting has a crosslinked average particle size of 30 μm.
Granular rubber (A) of m or less and Vicat softening point 121 to 1
A thermoplastic elastomer containing a thermoplastic resin (B) at 80 ° C., a thermoplastic resin (C) having a melting point of 50 to 120 ° C., and a softening agent (D), which is a granular rubber (A) / olefin resin (B). ) Is 90/10 to 50/50 (both are 100 parts by weight in total), and the total amount of (A) and (B) is 10
5 parts of resin (C) having a melting point of 50 to 120 ° C. to 0 part by weight
70 parts by weight and 5-100 parts by weight of the softening agent (D) are contained in the heat-shrinkable pipe joint according to claim 1 or 2. 4. A crosslinked granular rubber (A) for the pipe joint.
Is an ethylene / α-olefin copolymer rubber composed of ethylene and an α-olefin having 3 to 20 carbon atoms,
The ethylene / α-olefin / non-conjugated polyene copolymer rubber comprising ethylene, an α-olefin having 3 to 20 carbon atoms and a non-conjugated polyene is used as a raw material. Heat shrinkable pipe fitting. 5. The Vicat softening points 121 to 18 of the pipe joint.
The 0 ° C. thermoplastic resin (B) is a crystalline high molecular weight solid resin obtained from the polymerization of one or more mono-olefins by either a high pressure process or a low pressure process. The heat shrinkable pipe joint according to any one of 1 to 4. 6. The thermoplastic resin (C) having a melting point of 50 to 120 ° C. of the pipe joint is a copolymer composed of two or more kinds of α-olefins selected from α-olefins having 2 to 12 carbon atoms. The heat-shrinkable pipe joint according to claim 1. 7. A heat-shrinkable pipe joint according to claim 1,
A pipe joint part having an outer diameter (Dp) and a wall thickness (tp) to be joined. 8. A pipe joint part in which a pipe having an outer surface having a flat shape, a spiral shape, or a ring shape is joined by using the heat-shrinkable pipe joint according to any one of claims 1 to 6.