JP2000257786A - Connecting method of polyethylene pipe or member and polypropylene pipe or member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method to heat-fuse a pipe and a pipe or a pipe and a member under a method to connect a polyethylene pipe or member and a polypropylene pipe or member. SOLUTION: This connecting method is to connect a polyethylene pipe or member and a polypropylene pipe or member to each other. In this case, the pipe and the pipe or the pipe and the member are heat-fused by using the pipe or a joint, a film or a sheet type connecting member blending polyethylene 10-90 wt.% and polypropylene 90-10 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a water pipe, a sewer pipe,
The present invention relates to a method for connecting a member such as a polyethylene pipe or a polyethylene saddle or a mass used for a building member or the like to a member such as a polypropylene tube or a polypropylene saddle or a mass.

[0002]

2. Description of the Related Art In recent years, polyethylene pipes have attracted attention for durability, flexibility, impact resistance and the like, and are used for water supply, drainage, sewerage, and the like. In general, the connection between polyethylene pipes and the connection between pipes and members such as joints are performed by mechanical joints, RR joints using packing, or fusion welding that fuses and connects a part of tubes and members using a heater or heating wire. A method called has been performed. Among these, the connection by fusion has a feature that the connection portion is extremely unlikely to be destroyed by deformation such as elongation of the pipeline since the connected ones are integrated. on the other hand,
Polypropylene pipes, which have excellent rigidity and heat resistance, have also attracted attention in recent years, and are being used for drainage, building members, and the like. The same method as that for the polyethylene pipe is used for the connection between the polypropylene pipes.

[0003] As polyethylene pipes and polypropylene pipes are widely used, it becomes necessary to join pipes and members made of polyethylene and polypropylene made of different materials. For the joining of polyethylene and polypropylene, it is preferable to integrally connect by fusion from the viewpoint of strength. However, direct fusion of pipes and members made of these two materials is not possible when polyethylene and polypropylene are fused. No, because there is no so-called compatibility, even if it looks like they are fused,
When a peeling test was performed, the strength of the fused portion was significantly lower than that of the base material. Therefore, mechanical joints and RR
A joint was used.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for connecting a polyethylene pipe or member to a polypropylene pipe or member by heat-sealing the pipe or tube or the tube and member. is there.

[0005]

In order to connect a polyethylene pipe or a member to a polypropylene pipe or a member by heat fusion, the present inventors have proposed a joining method which is a pipe or a joint in which polyethylene and polypropylene are mixed at a specific ratio. By joining using a member or inserting a sheet or film-like joining member in which polyethylene and polypropylene are mixed in a specific ratio into the joint between the polyethylene tube or the member and the polypropylene tube or the member, the polyethylene tube is joined. Alternatively, they have found that the member and the polypropylene tube or member can be firmly heat-sealed, and have completed the present invention.

That is, the present invention relates to a method for connecting a polyethylene pipe or member to a polypropylene pipe or member, wherein the joining member is a pipe or joint containing 10 to 90% by weight of polyethylene and 90 to 10% by weight of polypropylene. A method for connecting a polyethylene pipe or a member to a polypropylene pipe or a member, wherein the pipe and the pipe or the pipe and the member are thermally fused.

Further, the present invention provides a method for connecting a polyethylene pipe or member to a polypropylene pipe or member, wherein a film or sheet-like joining member containing 10 to 90% by weight of polyethylene and 90 to 10% by weight of polypropylene is blended. A method for connecting a polyethylene pipe or a member and a polypropylene pipe or a member, wherein the method is inserted into a joint portion and the tube and the tube or the tube and the member are thermally fused.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Polyethylene pipe The polyethylene pipe used in the present invention is a pipe formed by extrusion molding or injection molding of a polyethylene resin such as high-density polyethylene, medium-density polyethylene, linear low-density polyethylene, low-density polyethylene, or a compound thereof. Examples of the high-density polyethylene include a polyethylene homopolymer, or a copolymer of ethylene and an α-olefin such as propylene, 1-butene, 1-hexene, 4-methylpentene-1, or 1-octene as a comonomer. Examples of the medium-density polyethylene and low-density polyethylene include those obtained by copolymerizing ethylene and an α-olefin such as propylene, 1-butene, 1-hexene, 4-methylpentene-1, or 1-octene as a comonomer. Can be

These polyethylene resins are polymerized using a Ziegler-Natta type catalyst (a so-called titanium catalyst) or a Phillips catalyst (a so-called chromium catalyst) by a so-called middle-low pressure method under one-stage or two-stage or more different polymerization conditions. It is preferable to use a polyethylene resin which has been used. Further, it is more preferable to use a polyethylene resin which is a so-called metaceron type polymer polymerized by using a metallocene catalyst and is polymerized under one or two or more different polymerization conditions.

[0010] 2. Polyethylene member Examples of the polyethylene member used in the present invention include a socket joint, a saddle, a cheese, a cap, a square, and the like obtained by injection molding and extrusion molding using the above polyethylene resin.

3. Polypropylene tube and member The polypropylene tube used in the present invention is a polypropylene homopolymer, a random copolymer obtained by copolymerizing propylene with ethylene or 1-butene, and a rubber component such as ethylene-propylene rubber or ethylene-butylene rubber dispersed in a polypropylene homopolymer. It is a tube formed by extrusion molding or injection molding of the block copolymer.
Examples of the polypropylene member include joints, saddles, cheeses, caps, and squares formed by injection molding and extrusion molding using these resins.

4. Joining member The joining member used in the present invention is formed by mixing 10 to 90% by weight of polyethylene and 90 to 10% by weight of polypropylene through an extruder in advance, or compounding the pellets immediately before molding, and by injection molding and extrusion molding. Pipes, fittings (saddles, cheeses) or sheets or films manufactured by extrusion. Furthermore, it is also possible to produce an electrofusion joint using the above resin mixture.

As the polyethylene and polypropylene used for the joining member used in the present invention, it is preferable to use a polyethylene pipe, a polypropylene pipe to be joined, or the same resin as those members. The melt flow rate (MFR) of each resin is 0.03 to 10 g / 1.
0 minutes is preferable, and 0.05 to 5 g / 10 minutes is desirable.
If the MFR is less than 0.03 g / 10 min, the injection and extrudability are poor, and if it is more than 10 g / 10 min, the strength becomes insufficient, which is not preferable.

The mixing ratio of polyethylene and polypropylene in the joining member is such that polyethylene is 10 to 90% by weight, polypropylene is 90 to 10% by weight, and polyethylene is 20 to 80% by weight. Polypropylene is preferably 80 to 20% by weight, and desirably polyethylene is 40 to 60% by weight and polypropylene is 60 to 40% by weight. If the content of polyethylene or polypropylene is less than 10% by weight, the strength of the fused portion cannot be obtained. In addition, as long as the above-mentioned polyethylene and polypropylene do not deteriorate the performance of the resin, polymer additives and fillers such as commonly used antioxidants, ultraviolet absorbers, heat stabilizers, lubricants, crystallization nucleating agents, pigments, etc. Etc. can be used.

[0015] 5. Connection method In the connection method used in the present invention, a joining member is interposed between a polyethylene pipe or member and a polypropylene pipe or member, and the three members are melt-joined using a heater. For example, in the case of connection between a pipe and a pipe, a joint member in the form of a socket joint is installed between a polyethylene pipe and a polypropylene pipe to be connected, and the polyethylene pipe and the joint member are heat-fused. Finally, the polyethylene pipe and the polypropylene pipe are connected by heat-sealing the polypropylene pipe and the joining member. Alternatively, it is also possible to install a joining member in the shape of a saddle joint on a polyethylene tube and connect the polypropylene tube in a branch shape by heat fusion. The connection between the polypropylene tube and the saddle made of polyethylene is performed by installing a sheet or film-like joining member on the tube surface of the saddle and performing heat fusion. The heat fusion temperature in the bonding of the present invention is 200 to 250 ° C., preferably 21 to 250 ° C.
0-230 ° C.

A polyethylene pipe or member that is incompatible with simple fusion and a polypropylene pipe or member are fused with the same polyethylene and polypropylene components contained in the joining member to maintain the strength of the fused portion. In the joining member, polyethylene and polypropylene are mixed in a molten state in the extrusion step, so that the strength and the like of the joining member are almost the same as those of the polyethylene pipe and the polypropylene pipe.

Here, when a polyethylene resin produced with a metallocene catalyst is used as the polyethylene for the polyethylene pipe or member and / or the joining member, the polyethylene resin has an extremely narrow molecular weight distribution and crystallinity distribution, and a conventional polyethylene resin. Compared with polypropylene, it has a property that it is very easily mixed when mixed with polypropylene, that is, has a very high compatibility, so that the strength of the fused portion after joining is high.

[0018]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples. In addition, the test method in an Example is as follows. (1) MFR: Measured at 190 ° C. for polyethylene and 230 ° C. for polypropylene under a load of 2.16 kg in accordance with JIS K7210. (2) Judgment of fusion performance: 5 pieces of a 10 mm-wide strip-shaped test piece having a length such that the fusion portion is the center from the fusion portion
This cutout was subjected to a tensile test. Judgment of fusion bonding is judged to be acceptable only when ductile fracture has occurred at the fusion joint in all tensile tests, or when fracture has occurred at the pipe or member part. The test was rejected when unseen destruction (hereinafter referred to as interfacial peeling) occurred.

Example 1 As a polyethylene pipe, a high-density polyethylene (M
FR = 0.06 g / 10 min, density = 0.950 g / cm
³ ) Extruded pipe (outer diameter 60mm, wall thickness 5m)
m) was used. As a polypropylene pipe (MF
A pipe (outer diameter 60 mm, wall thickness 5 mm) extruded from R = 0.6 g / 10 min, homopolymer) was used. As a joining member, a pipe (outer diameter 75 mm, wall thickness 10 mm) formed by molding a material in which the high-density polyethylene and the polypropylene homopolymer were previously compounded in an extruder at a ratio of 50:50 (weight ratio) was cut into a length of 100 mm. Using the socket joint prepared as described above, fusion was performed using a 210 ° C. heater for heat fusion. As a result of cutting out a test piece so as to include the joint and conducting a tensile test, no interfacial peeling was observed.

Comparative Example 1 The pipes were connected in the same manner as in Example 1 except that the joining member was made of the polypropylene homopolymer of Example 1. Cut out the test piece to include the joint,
As a result of the tensile test, interfacial peeling occurred at the fusion surface between all the polyethylene pipes and the joining members.

Comparative Example 2 Connection of pipes was performed in the same manner as in Example 1 except that the joining member was made of a resin in which 95% by weight of the high-density polyethylene and 5% by weight of the polypropylene homopolymer were previously blended by an extruder. Was done. A test piece was cut out so as to include the joint, and a tensile test was performed. As a result, interfacial peeling occurred at the joint between the three joining members out of five and the polypropylene pipe.

Example 2 A high-density polyethylene (M
FR = 0.15 g / 10 min, density = 0.954 g / cm
³ ) Low-density polyethylene (MFR = 2.0 g / 10 min, density = 60% by weight, manufactured using a metallocene catalyst)
A pipe (outer diameter 60 mm, wall thickness 5 mm) obtained by extrusion-molding a resin containing 0.898 g / cm ³ ) and 40% by weight was used. As the polypropylene pipe, a pipe made of a polypropylene block copolymer (MFR = 0.6 g / 10 min, ethylene content = 5.0% by weight) was used. As a joining member, low-density polyethylene 8 produced using the above-described metallocene catalyst and 12% by weight of the high-density polyethylene 8
% By weight and the above polypropylene block copolymer 80
A pipe (outer diameter 75 mm, wall thickness 10 mm) was formed by extrusion using a resin whose weight% was previously blended by an extruder. Using a socket joint prepared by cutting this pipe into a length of 100 mm, the pipe was fused using a 210 ° C. heat fusion heater. A test piece was cut out to include the joint and subjected to a tensile test. As a result, no interfacial peeling was observed.

Comparative Example 3 A fusion and tensile test were performed under the same conditions as in Example 2 except that the joining member was made of the polypropylene block copolymer of Example 2 alone. As a result, interface peeling between the polyethylene pipe and the joining member occurred in one of the five pipes.

Example 3 As the polyethylene pipe, the high-density polyethylene of Example 2 (MFR = 0.15 g / 10 min, density = 0.95)
4 g / cm ³ ) extruded pipe (outer diameter 60 mm,
(Thickness: 5 mm). As a polypropylene pipe, a polypropylene block copolymer (MFR = 0.
6 g / 10 min, ethylene content = 5.0% by weight) was used. As a joining member, a resin in which 45% by weight of the high-density polyethylene, 30% by weight of the low-density polyethylene manufactured using the metallocene catalyst, and 25% by weight of the polypropylene block copolymer are previously compounded by an extruder is used for extrusion molding. To form a pipe (outer diameter 75 mm, wall thickness 10 mm). Using a socket joint made by cutting this pipe to a length of 100 mm,
Using a heater for heat fusion. A test piece was cut out to include the joint and subjected to a tensile test. As a result, no interfacial peeling was observed.

[0025]

The method for connecting a polyethylene pipe or member to a polypropylene pipe or member according to the present invention uses a joint member which is a pipe or joint in which polyethylene and polypropylene are blended in a specific ratio, or a sheet or film-like joint member. Since the joining member is inserted between the polyethylene material and the polypropylene material and thermally fused, the polyethylene material and the polypropylene material are firmly joined, and the water pipe, the sewage pipe,
It can be suitably used in the field of building members and the like.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 23:04 23:10 (72) Inventor Katsuyo Kazuyama 1-1-10 Yurakucho, Chiyoda-ku, Tokyo Japan F-term in the Polyolefins Division of Polychem Corporation (reference) 3H019 GA02 4F071 AA15 AA20 AH03 AH19 CA02 CD02 CD07 4F211 AA04 AA05 AA11 AD05 AD08 AD12 AG08 AH11 TA01 TC07 TC11 TD07 TD11 TN24 TN29

Claims (4)

[Claims] 1. A method for connecting a polyethylene pipe or member to a polypropylene pipe or member, the method comprising the steps of:
A method for connecting a polyethylene pipe or a member to a polypropylene pipe or a member, wherein the pipe and the member or the tube and the member are heat-sealed by using a joining member which is a tube or a joint in which the weight% is mixed. 2. A method for connecting a polyethylene pipe or member to a polypropylene pipe or member, the method comprising the steps of:
% By weight is inserted into the joint, and a tube or tube or a tube and the member are heat-sealed to connect the polyethylene tube or the member to the polypropylene tube or the member. Method. 3. The connection method according to claim 1, wherein the polyethylene pipe or the member is a molded article containing a resin produced by using a metallocene catalyst. 4. The polyethylene used for the joining member,
2. A resin produced using a metallocene catalyst.
4. The connection method according to any one of items 1 to 3.