JPH0557792A - Vinyl chloride resin pipe for lining of existing pipe - Google Patents

Abstract

PURPOSE:To prevent breaking of a lining pipe, which is ascribable to a pressure change of a circulating liquid within the lining pipe and contrive an improvement in respect of sanitation, by a method wherein a residual rate of inner stress strain after lining is reduced and the lining pipe is made free from eluation of a poisonous substance. CONSTITUTION:Chlorinated polyethylene having a mean molecular weight of 20X10<4> to 25X10<4> is used selectively as a modifier and the 5-20 pts.wt. chlorinated polyethylene is compounded with polyvinyl chloride on the basis of 100 pts.wt. of the same. Then a tin stabilizer is used as a stabilizer and 1.0-4.5 pts.wt. stabilizer is compounded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vinyl chloride resin pipe for lining the inner surface of an existing pipe, more specifically, for repairing an existing pipe such as a water supply pipe line buried underground or in a building body, The present invention relates to a vinyl chloride resin pipe for a lining, which is subsequently inserted into an inner surface for reinforcement or the like and is installed in a lined state.

[0002]

2. Description of the Related Art The existing pipe as described above may be unexpectedly damaged or cracked due to corrosion due to the passage of a long time, external pressure from the surroundings, internal pressure due to a fluid in the pipe, or the like. If these damages occur, for example, in underground water pipes, drinking water may become turbid due to intrusion of groundwater, and water pressure may be reduced due to a decrease in water pressure in the pipes. However, in practice, in the case of an existing pipe of this type, which is buried underground of a building on the ground or buried in the body of the building itself, it is difficult to replace itself.

For this reason, recently, for repairing or reinforcing the existing pipe as described above, a lining construction method in which a synthetic resin pipe is subsequently inserted inside the pipe and the inner surface is lined has attracted attention. This lining method is disclosed in Japanese Patent Application Laid-Open No. 1-29558.
As can be seen in Japanese Patent No. 28, a thermoplastic synthetic resin pipe having an outer diameter smaller than its inner diameter is inserted into the existing pipe to be repaired in a heat-softened state, and then a steam is introduced into the resin pipe. By applying internal pressure, the resin pipe is expanded in the radial direction and brought into close contact with the inside of the existing pipe, after which a cooling medium is introduced and cooled and solidified as it is.

By the way, conventionally, the resin pipe for lining used in the above-mentioned lining construction method is generally widely used as a material for constructing an underground conduit from the viewpoints of material cost, durability, thermal deformation durability and the like. Such hard vinyl chloride resin pipes are often used. This vinyl chloride resin tube is a mixture of polyvinyl chloride resin with a general MBS-based modifier as a modifier and a heat-resistant lead-based stabilizer as a stabilizer. Colorants, lubricants,
It is a mixture of pigments and the like, formed into a long tubular body by an extrusion molding method, reheated to be softened and wound on a drum, and carried into the construction site in the state of this wound material,
Has been used.

[0005]

However, when lining construction of an existing pipe is performed using the conventional hard vinyl chloride resin pipe as described above, it is found that the following problems occur after the construction. I've been

The first problem is that, especially when the lining of the water supply pipeline is performed, the fluctuation of the internal water pressure inevitably applied to the pipeline, especially the intermittent occurrence of water hammer phenomenon. This is because the shocked change in water pressure may cause the lining of the resin pipe to break even under internal water pressure conditions below the standard value.

The inventors of the present invention have made various investigations into the causes of such problems, and have found that they are mainly attributable to the following reasons. That is,
The lining resin pipe is expanded by introducing steam after it is inserted into the existing pipe at the time of construction and is intimately contacted with the inner surface of the existing pipe.However, in order to prevent contraction and restoration in the subsequent cooling process, the vapor in the pipe is compressed air. It is assumed that cooling is performed while maintaining the internal pressure during expansion. For this reason, the lining resin pipe is lined while retaining its own internal strain, and even a slight external stress may cause breakage.

The second problem is that the raw material for the lining resin pipe contains metallic lead added as a stabilizer as described above, so that it flows through the pipe particularly when used for lining water supply pipelines. This is the point where metallic lead, which is designated as a non-medicinal powerful drug, elutes in drinking water. Elution amount is JIS K 6
Although it is estimated that the amount of lead dissolved in the hard vinyl chloride pipe for water supply specified in 742 is less than the specified value, there is a concern that it will have an adverse effect on the human body due to long-term intake, so elution should be suppressed as much as possible. It goes without saying that it is desirable.

An object of the present invention is to provide a lining resin pipe which can solve the above problems.

[0010]

As a result of earnest studies for the above object, the present invention has made it possible to obtain a resin after expansion deformation by mixing a certain amount of chlorinated polyethylene having a molecular weight in a specific range with polyvinyl chloride resin. The internal strain remaining in the pipe, that is, the residual stress, can be greatly reduced compared to conventional products, and the use of tin-based stabilizers specified in the PL standard as stabilizers allows the elution of toxic substances. It has been completed by finding that it is possible to manufacture a vinyl chloride resin tube that is free from the risk of heat deterioration and that does not suffer from heat deterioration.

That is, one of the inventions is 100 parts by weight of polyvinyl chloride resin and a molecular weight of 20 × 10 ^{4 to} 25 × 10.
^A vinyl chloride resin pipe for lining an existing pipe, characterized by being mixed with 5 to 20 parts by weight of chlorinated polyethylene of ⁴ .

According to another aspect of the invention, in the resin pipe of the first aspect of the present invention, a tin-based stabilizer is selectively used as a stabilizer, and the stabilizer is 1.0% by weight with respect to 100 parts by weight of the polyvinyl chloride resin.
~ 4.5 parts by weight are blended.

[0013]

[Detailed Description of Means] As the polyvinyl chloride resin used in the present invention, an average degree of polymerization of homopolymerization of 400 to 400
A polyvinyl chloride resin in the range of 1350 or a mixture of two or more thereof is preferably used.

Chlorinated polyethylene is used as a modifier in place of the MBS type modifier used in conventional general vinyl chloride resin pipes. First,
The chlorinated polyethylene used as the modifier may have a chlorination degree of about 30 to 40%, but has an average molecular weight of 20 × 10 ^{4 to} 25 × 10 ^4.
It is necessary to use the thing of the range of. You may use the said molecular weight range 1 type or in mixture of 2 or more types. When an average molecular weight of less than 20 × 10 ⁴ is used, the tensile strength of the resin pipe after molding becomes insufficient, and when an average molecular weight of more than 25 × 10 ⁴ is used, after the lining resin pipe is applied. The effect of relaxing the internal strain, that is, the effect of reducing the residual stress is insufficient, and the object of the present invention cannot be achieved well. The most preferable average molecular weight of chlorinated polyethylene is 22 × 10 ^{4 to} 24 ×.
The range is 10 ⁴ .

The amount of the chlorinated polyethylene compounded is 5 to 2 with respect to 100 parts by weight of the polyvinyl chloride resin.
It is limited to the range of 0 parts by weight. If the blending amount is less than 5 parts by weight, the effect of reducing internal strain will not be exhibited, and if the blending amount exceeds 20 parts by weight, the rigidity of the resin pipe, particularly the tensile strength, will be extremely reduced, and the resin pipe for lining As a result, the required practical strength cannot be obtained. The most preferable compounding amount is in the range of 8 to 15 parts by weight with respect to 100 parts by weight of the polyvinyl chloride resin.

The tin-based stabilizer used as the stabilizer in the present invention is, for example, poly (di-n-octyltin maleate), bis (monoester of maleic acid-n-octyltin), laurate-n-octyltin. , Bis (isooctyl thioglycolate) di-n-octyl tin, dithioglyco-late tetramethylene di-n-octyl tin, tris (isooctyl thioglycolate) n-
Octyl tin and the like can be mentioned, and one or more of these can be preferably used. Therefore, the use of stabilizers other than the above tin-based stabilizers is excluded in this invention. That is, lead-based stabilizer, cadmium
Barium stabilizers are particularly unsuitable as lining materials for water supply pipes in that they include substances specified as non-medicinal powerful drugs, and Ca-Zn stabilizers are thermally deteriorated by heating during extrusion molding. Can not be used because.

If the amount of the tin-based stabilizer compounded is less than 1.0 part by weight with respect to 100 parts by weight of the polyvinyl chloride resin, the thermal stability at the time of extrusion molding of the resin tube will be insufficient, resulting in 4.5 parts by weight. If it exceeds, the effect of improving the thermal stability will no longer be saturated, which is rather disadvantageous from the economical aspect. The most preferable range of the blending amount is 1.5 to 4.0 parts by weight in the total amount of one or more tin stabilizers.

In addition, the resin composition applied to the vinyl chloride resin pipe for lining according to the present invention includes the above-mentioned polyvinyl chloride resin, tin-based stabilizer, chlorinated polyethylene, and
It goes without saying that processing aids, lubricants, fillers, pigments, colorants and the like can be added. The types and blending amounts of these additives are not particularly limited as long as they follow conventional methods for producing resin pipes. For example, the processing aid may be added in an amount of 1 to 5 parts by weight, and the filler may be added in an amount of 0.5 parts by weight or less, if necessary, for titanium oxide or a pigment.

The production of the resin pipe according to the present invention is
It is carried out according to the usual extrusion molding method, and the manufacturing conditions and the like are not limited in any way.

[0020]

According to the vinyl chloride resin pipe for lining made of the resin composition of the present invention, as shown in the examples described later, it has excellent relaxation property of internal stress strain over time after deformation as compared with the conventional product. Can be. Therefore, when lining is applied to the inner surface of an existing pipe to repair it, even if internal strain occurs due to cooling and solidification while retaining the internal pressure after heating and expansion while suppressing shrinkage, this strain is short-lived. It is clear that it can be alleviated. Therefore, even when it is used for lining of water supply pipes where the internal pressure changes repeatedly, there is no risk of breakage accidents due to changes in the internal water pressure, further improving the durability and reliability of lining construction. can do.

In addition, by using a tin-based stabilizer as the stabilizer as in claim 2, the toxicity of the tin-based stabilizer is lower than that of the conventional lead-based stabilizer. In particular, it can be made suitable for the lining of water supply lines.

[0022]

EXAMPLE Using various resin compositions having the composition shown in Table 1 in which the kind, the molecular weight, and the compounding amount of the modifier were changed as shown in Table 2, a diameter of 170 mm and a wall thickness of 3.7 mm were obtained by extrusion molding. Various polyvinyl chloride resin pipes (P) were manufactured.

[0023]

[Table 1]

Next, test pieces (S) were cut out from the various polyvinyl chloride resin pipes (P) produced as described above as shown in FIG. 1, and the tensile strength was measured according to JIS K 6745 to determine the rigidity. The judgment value was used.

Using the same test piece (S), both ends of the test piece are fixed by chucks (T) as shown in FIG. 2, and then the test piece (S) is pulled in the longitudinal direction. To 1
An initial stress of 00 kgf / cm ² was applied, and the stress residual ratio was measured by the load measuring device (M) until 100 hours later.

The measurement results of the tensile strength and the stress residual ratio after 100 hours are also shown in Table 2.

[0027]

[Table 2]

As shown in Table 2, chlorinated polyethylene having a molecular weight of 20 × 10 ^{4 to} 25 × 10 ⁴ was blended in a range of 5 to 20 parts by weight with respect to 100 parts by weight of vinyl chloride resin as a modifier. Polyvinyl chloride resin pipe (Examples 1 to 1
6) is a blend of chlorinated polyethylene having a molecular weight and a blending amount out of the above ranges (Comparative Examples 7 to 10), and a commonly used MBS-based or MMA-based modifier or impact resistance. Compared to those containing a reinforcing agent (Comparative Examples 11 to 13), the strength is not deteriorated, and the strength is further improved as compared with the conventional product, and the relaxation property of internal stress strain over time is improved. It was confirmed that it was excellent.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a state in which a test piece is taken out from a resin tube.

FIG. 2 is a diagram showing a measurement state of a residual stress rate with time of a test piece.

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Claims (2)

[Claims] 1. A mixture of 100 parts by weight of polyvinyl chloride resin and 5 to 20 parts by weight of chlorinated polyethylene having a molecular weight of 20 × 10 ^{4 to} 25 × 10 ⁴ ,
Vinyl chloride resin pipe for lining existing pipes. 2. The existing method according to claim 1, wherein a tin stabilizer is selectively used as the stabilizer, and the stabilizer is blended in an amount of 1.0 to 4.5 parts by weight with respect to 100 parts by weight of the polyvinyl chloride resin. Vinyl chloride resin pipe for pipe lining.