JP2000283369A - Polyolefin joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constantly provide a stable joint part by applying a processing agent including a silicon compound, or a treatment agent including a silicon compound and a reaction accelerator between an EF joint and polyolefin pipes. SOLUTION: In the manufacturing of an EF(electrofusion) joint as a polyolefin joint 11, a solvent such as toluene, xylene, benzene, ethanol, methanol is added to a predetermined silicon compound, or to the silicon compound and a reaction accelerator such as benzoyl peroxide, dichlorobenzyl peroxide, dicumyl peroxide, or a treatment agent is prepared without adding the solvent, and the treatment agent is applied between an inner surface 13 of the polyolefin joint 11 and the polyolefin pipes 15, 17 by a conventional method. Then the polyolefin joint 11 and the polyolefin pipes 15, 17 are heated and deposited to be joined to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a joint for a polyolefin pipe.

[0002]

2. Description of the Related Art Conventionally, the joining of polyolefin pipes (tubes made of polyethylene, polypropylene, polybutene, polymethylpentene, etc.) for gas, water, hot water supply and heating has been carried out by electro-forming. The fusion method (EF method) is used. As shown in FIGS. 1 and 2, this method uses a polyolefin electrofusion joint (EF joint) in which a heating wire 1 is spirally embedded in the vicinity of an inner peripheral surface in advance during manufacturing.
After setting the two polyolefin pipes 5 and 7 to be joined, a predetermined electric energy is supplied to the heating wire 1 from a controller (not shown) to generate heat, so that the inner surface of the EF joint 3 is generated. This is a method of melting and joining the parts and the outer surface parts of the polyolefin pipes 5 and 7.

[0003] The EF method is 1) simple in construction, so that operations such as joining and repairing after pipe cutting can be easily performed. 2)
Advantages such as stable construction quality on site due to easy automation, 3) low tool cost and low tool maintenance cost, 4) high cost of EF joint, but reduced total construction cost It is rapidly spreading.

[0004] When joining polyolefin pipes by the EF method, in order to form a good fusion-bonded section, as a pretreatment, a pipe surface is scraped and wiped with an organic solvent such as acetone or alcohol. ing. By these pretreatments, oxides on the polyolefin pipe surface are removed (usually about 20 μm), and deposits on the pipe surface (sand, muddy water, machine oil, grease, polyolefin fine pieces generated by hooking, etc.) are removed. A good fusion bonding state between the joint and the pipe is obtained.

However, in practice, the joining of polyolefin pipes by the EF method is often carried out on site where it is difficult to ensure good working conditions. Therefore, even after the completion of the above pretreatment, a state in which good fusion bonding is inhibited is likely to occur. A typical example is the adhesion of fine sand to the surface of a polyolefin pipe or the surface of an EF joint. Such adhesion of sand
Often not visible to the naked eye, EF as it is
EF joints-polyolefin pipes may be joined by the method. It has been confirmed that almost no trouble occurs under normal conditions even in the bonding obtained in such a state. However, if an abnormal force is applied to such a joint due to an earthquake or the like, there is a risk that cracks may progress from the incompletely welded portion and gas leakage may occur.

[0006] A main object of the present invention is to provide a polyolefin joint which can always obtain a good joint even in a joining operation of a polyolefin pipe on site.

[0007]

Means for Solving the Problems The present inventors have made intensive studies in view of the state of the prior art as described above, and as a result, EF
When a treatment agent containing a silicon compound or a treatment agent containing a silicon compound and a reaction accelerator is applied between the joint and the polyolefin tube and heated, the fusion bonding between the EF joint and the polyolefin tube is extremely excellent. Found to be done. Further, at this time, it was found that even if fine sand adhered to the surface of the polyolefin pipe or the surface of the EF joint, it did not substantially affect the bonding strength between the two.

That is, the present invention provides the following polyolefin joint. Item 1. A polyolefin joint for joining a polyolefin pipe, wherein the joint has a treating agent containing a silicon compound or a treating agent containing a silicon compound and a reaction accelerator inside the joint. Item 2. Item 2. The polyolefin joint according to Item 1, wherein a treatment agent containing a silicon compound or a treatment agent containing a silicon compound and a reaction accelerator is attached to a coating portion of the coating heating wire on the inner surface of the joint. Item 3. Item 2. The polyolefin joint according to Item 1, wherein a treatment agent containing a silicon compound or a treatment agent containing a silicon compound and a reaction accelerator is attached to a heating wire on the inner surface of the joint. Item 4. Item 2. The polyolefin joint according to Item 1, wherein a treatment agent containing a silicon compound or a treatment agent containing a silicon compound and a reaction accelerator is attached to the inner surface of the joint other than the coated heating wire and the heating wire.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The joint made of polyolefin used in the present invention is not limited to an EF joint, but may be an external heat source (heater).
HF joints using the same.

Known polyolefin tubes can also be used.

In the present invention, the silicon compound contained in the treating agent to be present inside the polyolefin joint may have a Si—Si bond, Si—H bond, Si—O bond or Si—X (X = hydroxyl group, alkoxy group) in the molecule. , A halogen atom, at least one of an amino group and an amide group) and Si-R (R = at least one of a hydrocarbon group such as an alkyl group, an alkenyl group, and an aryl group).
).

Examples of such a silicon compound are shown below.

1. Polysilane: Polysilane refers to a compound having at least one Si-Si bond in a main skeleton structure of a chemical structure, and a group generally represented by R ^{1 to} R ³ bonded to Si. Examples of such polysilanes include those represented by the following general formulas (1) to (3). General formula (1)

[0014]

Embedded image

(Wherein R ¹ and R ² are the same or different and each represent a hydrogen atom, a halogen atom, a hydroxyl group, a C 1-20
Is selected from the group consisting of alkyl groups, alkenyl groups, aryl groups, alkoxy groups, amino groups, amido groups and silyl groups; m is usually about 2 to 10,000, more preferably about 2 to 100, A linear polysilane and a cyclic polysilane represented by the following general formula (2):

[0016]

Embedded image

(Wherein R ³ is a hydrogen atom, a halogen atom,
Selected from the group consisting of a hydroxyl group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group, an aryl group, an alkoxy group, an amino group, an amide group and a silyl group;
, More preferably about 2 to 100, and particularly preferably about 2 to 10), a silicon network polymer represented by the following general formula (3):

[0018]

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(In the formula, R ^{1 to} R ³ are the same or different from each other by two or more, and represent a hydrogen atom, a halogen atom, a hydroxyl group,
Selected from the group consisting of 1-20 alkyl, alkenyl, aryl, alkoxy, amino, amido and silyl groups; the sum of x, y and z is usually from 5 to 1
About 0000, more preferably about 5 to 100, and particularly preferably about 5 to 10).

Such a polysilane compound is prepared by using a monomer having each structural unit as a raw material and a) dehalogenating polycondensation of a halosilane in the presence of an alkali metal ("Kipping method", J. Am. Chem. Soc., 110, 124 (198
8), Macromolecules, 23, 3423 (1991)) b) Dehalogenation polycondensation of halosilanes by electrode reduction (J. Ch.
em.Soc., Chem.Commun., 1161 (1990), J. Chem. Soc., Chem.
Commun., 897 (1992)), c) a method of dehydrocondensation of hydrosilanes in the presence of a metal catalyst (JP-A-4-334551), a method of anionic polymerization of disilene cross-linked with biphenyl or the like (Macromolecules, 23,4494 (1990)) and ring-opening polymerization of cyclic disilanes.

As the polysilane, a linear polysilane and a cyclic polysilane represented by the general formula (1) are more preferable.

2. Polysiloxane: Polysiloxane is defined as having at least one Si in the main skeleton structure of the chemical structure.
A compound having a -O-Si bond and having a group generally represented by R (R = a hydrocarbon group such as an alkyl group, an alkenyl group, an aryl group) bonded to Si. Examples of such a polysiloxane include the following. General formula (4)

[0023]

Embedded image

(Wherein R ⁴ and R ⁵ are the same or different and each represent a hydrogen atom, a halogen atom, a hydroxyl group, a C 1-20
Selected from the group consisting of alkyl, alkenyl, aryl, alkoxy, amino, amido and silyl groups, at least one of which is a hydrogen atom, a halogen atom, a hydroxyl group, an alkoxy group, an alkenyl group, an amino group Or an amide group; m is about 2 to 10,000, more preferably about 2 to 100, and particularly preferably 2 to 10
Linear polysiloxane and cyclic polysiloxane represented by the general formula (5):

[0025]

Embedded image

(Wherein R ⁴ is a hydrogen atom, a halogen atom,
A hydroxyl group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group, an aryl group, an alkoxy group, an amino group, an amide group and a silyl group, at least one of which is a hydrogen atom, a halogen atom, a hydroxyl group, an alkoxy group; Group,
X is alkenyl, amino or amido; X is 4
About 10,000, more preferably about 4 to 100, and particularly preferably about 4 to 10), a general formula (6)

[0027]

Embedded image

(Wherein, R ^{4 to} R ^{6 each} include a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group, an aryl group, an alkoxy group, an amino group, an amide group and a silyl group) Selected from the group, at least one of which is a hydrogen atom, a halogen atom, a hydroxyl group, an alkoxy group, an alkenyl group, an amino group or an amide group;
The sum of x, y and z is usually about 5 to 10,000, more preferably about 5 to 100, and particularly preferably 5 to 10
A polymer having a skeleton of a Si-O-Si bond represented by the following formula:

3. General formula (7) R ⁴ R ⁵ R ⁶ R ⁷ Si (7) (wherein, R ^{4 to} R ⁷ are a hydrogen atom, a halogen atom, a hydroxyl group,
An alkyl group having 1 to 20 carbon atoms, an alkenyl group, an aryl group, an alkoxy group, an amino group and an amide group are selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group and an aryl group. And at least one of a hydrogen atom, a halogen atom, a hydroxyl group, an alkoxy group, an amino group and an amide group).

Examples of the silicon compound represented by the general formula (7) include vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxylan, γ- (methacryloyloxypropyl) trimethoxysilane, β -(3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N -β (aminoethyl)
γ-aminopropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, vinyltrichlorosilane, vinyl Trimethoxysilane, vinyltriethoxysilane, tris- (2-methoxyethoxy) vinylsilane, γ-glycidoxypropyltrimethoxysilane, γ- (methacryloxypropyl) trimethoxysilane, γ (2-aminoethyl) aminopropyltrimethoxysilane Preferred are methoxysilane, γ-chloropropyltrimethoxysilane, γ-aminopropyltrimethoxysilane and the like.

The silicon compounds represented by the general formulas (1) to (7) may be used alone or in combination of two or more.

Among these silicon compounds, the polysilane represented by the general formula (1) is most preferred. Also,
When polysiloxane is used, a linear one is preferable, and a peroxide is preferably used in combination as a reaction accelerator shown below.

In the treatment agent according to the present invention, a reaction accelerator can be used in combination to promote a fusion reaction between the pipe and the joint. As a reaction accelerator, benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di (peroxybenzoate) hexyne-3, 1, 4-bis (tert-butylperoxyisopropyl) benzene, lauroyl peroxide, tert-butylperacetate, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3,2,5-dimethyl -2,5-di (tert-butylperoxy) hexane, tert-butylperbenzoate, tert-butylperphenylacetate, tert-butylperisobutyrate, tert-butylper-tert-octoate, tert-butylperpivalate , Cumyl perpivalate, tert-butyl perdiethyl acetate and other peroxides and peresters; azobis-isobutyronitrile, dimethylazoiso Compounds generating radicals by heat, such as azo compounds such as Chireto; at least 1, such as a base such as pyridine, triethylamine; acetate, p- toluenesulfonic acid, acids such as hydrochloric acid
Seeds can be formulated. Among the compounds that generate radicals, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di (peroxybenzoate) hexyne-3, 2,5-dimethyl-2, Dialkyl peroxides such as 5-di (tert-butylperoxy) hexane and 1,4-bis (tert-butylperoxyisopropyl) benzene are more preferred.

The production of the polyolefin joint of the present invention and the joining of a polyolefin pipe using the polyolefin joint will be described with reference to FIGS.

In producing the polyolefin joint 11 of the present invention, a treating agent is prepared by adding a solvent to a predetermined silicon compound or a silicon compound and a reaction accelerator, or without adding a solvent, and preparing a treating agent by a conventional method. This treating agent is applied to the inner surface 13 of the polyolefin joint manufactured according to the above. In order to join the polyolefin pipes, the polyolefin pipes 15, 17 are inserted into the polyolefin joint 11 of the present invention, and then heated and fused according to a conventional method.

As the method of applying the treating agent, (a) a method of attaching the treating agent to a tissue paper or a paper sheet and applying it to the inner surface of the polyolefin joint, and (b) using a brush to apply the treating agent to the inner surface of the polyolefin joint. (C) a method of spraying and applying a treating agent to the inner surface of a polyolefin joint, (d) a method of directly immersing a polyolefin joint in the treating agent, and (e) applying a treating agent to a coated heating wire (coated wire) or A method of applying to the heating wire (wire) 19, (f) At the time of manufacturing the joint, a treating agent is applied in advance to the core, the heating wire (wire) or the coated heating wire (coated wire), and the inner surface of the joint is passed through the core. It is possible to adopt a method of applying the method or a method of using a heating wire (wire) coated with a treating agent in advance or a coated heating wire (coated wire) 19 as it is. Wear. As the coating method in the cases (e) and (f), known coating methods such as the above (a) to (d) can be adopted.

Examples of the solvent contained in the treatment agent include toluene, xylene, benzene, ethanol, methanol, isopropanol, n-propanol, butanol, butanol, tetrahydrofuran, dimethoxyethane, dimethylacetamide, and the like which have been conventionally used for wiping the tube surface. It is preferable to use ethylene glycol, triethylene glycol, tetraethylene glycol and the like.

The ratio of the silicon compound to the solvent is not particularly limited, but is usually about 0.1 to 100 parts by weight, more preferably about 1 to 40 parts by weight, based on 100 parts by weight of the solvent. When using a reaction accelerator, 10 parts by weight of the silicon compound, the solubility of the solvent or less,
It is preferably at most 10 parts by weight, more preferably at most 4 parts by weight.

The amount of the silicon compound applied to the joint surface inside the polyolefin joint is not particularly limited, but is usually about 0.001 to 100 g / m ² , and more preferably about 0.1 to 100 g / m ² .
It is a 01~50g / m ² about. The amount of the reaction accelerator used is also not particularly limited, but is usually 0.1% by weight of the silicon compound.
About 100%, more preferably about 0.5 to 40%. The heating conditions are also not particularly limited, but as a standard condition, it is about 200 ± 20 ° C., which is employed for heat fusion between ordinary polyolefin pipes and EF joints, for about 10 to 30 seconds.

When joining the polyolefin pipe using the polyolefin joint of the present invention, the polyolefin pipe may be previously hooked and / or wiped with alcohol as in the prior art. In this case, the joining characteristics between the pipe and the joint can be further improved.

It is presumed that the joining characteristics between the polyolefin pipe and the joint are remarkably improved by the present invention for the following reasons.

That is, Si—Si bond and / or Si—H
The silicon compound having a silyl radical generated by heating or in the presence of a radical initiator, reacts with the sand surface, the polyolefin pipe, and the oxide film of the polyolefin pipe,
Easy to form chemical bonds.

Si—X (X: at least one of a hydroxyl group, an alkoxy group, a halogen atom, an amino group or an amide group)
The silicon compound having a (species) easily reacts with the Si-OH on the sand surface to form a chemical bond.

The silicon compound having a Si—O bond is
It has affinity for Si-OH and Si-O on the sand surface.

On the other hand, silicon compounds having Si-R (R = hydrocarbon group such as alkyl, alkenyl, aryl group, etc.)
Has affinity with polyolefin tubes.

Therefore, when joining the polyolefin pipe and the polyolefin joint using the polyolefin joint of the present invention, even if sand remains on the surface of the polyolefin pipe, the sand itself chemically forms the joint. Since it is incorporated as a part, the strength of the joint is not significantly reduced.

[0047]

EXAMPLES Examples and comparative examples are shown below to further clarify the features of the present invention.

[Method of Applying Silicon Compound and Joint Strength Test] In the following examples, a treating agent obtained by adding methylphenylpolysilane having an average degree of polymerization of 6 to a predetermined solvent was mixed with a polyethylene EF joint (inner diameter 60.5 mm, meat (Thickness: 7.1 mm). Tissue paper,
Coating means such as a rag, a sprayer, a brush, and a direct dipping were used. In addition, a treatment agent was previously applied to the core during the production of the joint, and was applied to the inner surface of the joint through the core. Alternatively, a treatment agent was applied to the heating wire (wire) or the coated heating wire (coated wire) during the production of the joint.

On the other hand, according to a conventional method, the outer surface of a polyethylene pipe (outer diameter: 60.2 mm, wall thickness: 5.5 mm) immediately after being taken out of the packaging material or taken out of the packaging material and left outdoors is 0.2 mm.
After scraping, or without scraping, by pre-treatment by wiping with alcohol, and then a predetermined amount of sand (particle size: 10
6 μm or less).

Thereafter, this polyethylene pipe was set in the above-mentioned polyethylene EF joint, and the average clearance was 0.5 mm and the polyethylene pipe was 1 mm.
Energization was performed for 10 seconds to perform bonding. The power supplied at the time of this energization was about 4 W / cm ² , and the joint was maintained at a temperature of about 200 ° C. or more for about 20 seconds. Next, eight test pieces having a width of 10 mm were cut out at regular intervals in the pipe length direction of the joint, and as shown in FIG. 5, a connecting rod was welded to the end of the EF joint to perform a peel test. The length of the joint is 31mm (same as the heating zone width of the EF joint).
The tensile speed was 50 mm / sec.

Table 1 below shows the results obtained in the examples and comparative examples.

Example 1 A toluene solution having a methylphenylpolysilane concentration of 25% by weight was prepared, and the toluene solution of this polysilane was applied to the entire inner surface of the EF joint using a spray machine. Using an EF joint that was left for 30 days after application, in a state where a predetermined amount of sand was adhered to the scraped polyethylene pipe surface, heat fusion was performed to perform the joining operation, and finally using the test piece obtained from the joint part And a peel test.

Example 2 A joining operation and a peel test were performed in the same manner as in Example 1 except that an EF joint left for 60 days after application was used.

Example 3 A joining operation and a peel test were carried out in the same manner as in Example 1 except that an EF joint which was left to stand for 30 days after applying a toluene solution having a methylphenylpolysilane concentration of 10% by weight was applied.

Example 4 A joining operation and a peel test were carried out in the same manner as in Example 1 except that an EF joint which was allowed to stand for 30 days after applying an ethanol solution having a methylphenylpolysilane concentration of 25% by weight was used.

Example 5 At the time of producing a joint, methylphenylpolysilane concentration was 25% by weight.
The coated heating wire (coated wire) was directly immersed in the toluene solution of No. 1 to apply the toluene solution to the coated portion, and an EF joint was manufactured using the coated solution. A joining operation and a peel test were performed in the same manner as in Example 1 except that this EF joint was used.

Example 6 Methylphenyl polysilane concentration 25% by weight at the time of manufacturing the joint
A heating solution (wire) was directly immersed in a toluene solution of the above to apply a toluene solution, and an EF joint was manufactured using the solution. A joining operation and a peel test were performed in the same manner as in Example 1 except that this EF joint was used.

Comparative Example 1 A polyethylene pipe and an EF joint were joined in the same manner as in Example 1 except that the amount of adhered sand was 0.03 mg / cm ² and that no methylphenylpolysilane was applied, and a test piece was prepared. Cut-outs and peel tests were performed.

The bonding in this case substantially corresponds to the standard fusion bonding in use. However, it is clear that when a load of 35 kg or more is applied to the joint, the joint is easily broken.

Comparative Examples 2-3 A polyethylene tube and an EF joint were joined in the same manner as in Comparative Example 1 except that the amount of adhered sand was increased, and a test piece was cut out and subjected to a peel test.

It is clear that if a large amount of sand adheres, the joint will easily break at low load values.

[0062]

[Table 1]

Note: Residual length = length of heating wire inside joint (L ₁ ) −length brittlely peeled off at fusion interface As is clear from the results shown in Table 1, Comparative Example 1 Examples 1 to 6 show extremely high values for the load value and the remaining length, as compared with the results of the above.

From the above, it is apparent that the use of the polyolefin joint of the present invention significantly improves the characteristics of the polyethylene pipe joint even when sand is adhered.

[0065]

By using the polyolefin joint of the present invention, the joining characteristics of the polyolefin pipe through the polyolefin joint can be significantly improved even under disadvantageous working conditions on site.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an outline of a method for joining two polyolefin pipes using an EF joint.

FIG. 2 is a cross-sectional view showing an outline of a method for joining two polyolefin pipes using an EF joint.

FIG. 3 is a cross-sectional view showing an outline of a method for joining two polyolefin tubes using an EF joint according to the present invention.

FIG. 4 is a cross-sectional view showing an outline of a joining method of the present invention for joining two polyolefin pipes using an EF joint.

FIG. 5 is a side view showing an outline of a method of preparing a peel test piece and an outline of a test method in an example of the present invention.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Hiroaki Murase, Inventor 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka Inside Osaka Gas Co., Ltd. (72) Hiroyuki Nishimura 4-chome, Hirano-cho, Chuo-ku, Osaka, Osaka No. 1-2 Inside Osaka Gas Co., Ltd. Osaka Gas Co., Ltd., 4-1-2 cho, Tochio Yoshida 4-1-2, Hirano-cho, Chuo-ku, Osaka City, Osaka Prefecture F-term in Osaka Gas Co., Ltd. 3H019 GA03 GA06 4F211 AA03 AA33 AB19 AD12 AD34 AG08 AH11 TA01 TC07 TC11 TD07 TD11 TH02 TH22 TN24 TN31

Claims (4)

[Claims] 1. A polyolefin joint for joining a polyolefin pipe, comprising a treatment agent containing a silicon compound or a treatment agent containing a silicon compound and a reaction accelerator inside the joint. 2. A treatment agent containing a silicon compound or a treatment agent containing a silicon compound and a reaction accelerator is attached to a coating portion of a heating wire on the inner surface of the joint.
The polyolefin joint according to 1. 3. The polyolefin joint according to claim 1, wherein a treating agent containing a silicon compound or a treating agent containing a silicon compound and a reaction accelerator is attached to a heating wire on the inner surface of the joint. 4. The coating agent according to claim 1, wherein a treatment agent containing a silicon compound or a treatment agent containing a silicon compound and a reaction accelerator is adhered to the inner surface of the joint other than the coated heating wire and the heating wire. Polyolefin fitting.