JP2000352480A - Resin pipe and its use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin pipe which has small drawing stress even at a low temperature and is excellent in productivity by using ionomer in at least one layer. SOLUTION: Ionomer resin kneaded by an extruder 1 is extruded as a cylindrical extruded material 2 through a ring-like die orifice of the extruder, and the cylindrical extruded material 2 is taken over by a take-over machine A to be forcibly passed through a sizing die 3, so that it is formed to designated shape and dimenions. A water tank A is provided between the sizing die 3 and the take-over machine A, and the extruded material 4 formed by the sizing die 3 is cooled and solidified under the condition where expansion force by vacuum is applied in the water tank A. A take-over machine B is driven at a higher speed than the take-over machine A, water heated to a drawing temperature is stored in a water tank B, and water for cooling is stored in a water tank C. A drawing pipe 6 is cooled and stabilized in the next water tank C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin pipe which is useful as a pipe lining coating material or a pipe inner surface repairing material, at least one layer of which is made of an ionomer resin, and more particularly to a metal pipe, a thermosetting resin. The present invention relates to a resin pipe suitable for coating or repairing the inner surface of various pipes such as pipes, glass pipes, and wooden pipes, and a coating material and a coating method for a pipe lining using the resin pipe, and a pipe inner surface repair using the resin pipe. It also relates to repair methods for materials and pipes.

[0002]

2. Description of the Related Art As a steel pipe for water and sewage, for transporting chemicals, and the like, a lining steel pipe in which a resin is tightly lined is widely used. As such a lining resin,
Conventionally, a pipe provided with an adhesive layer on the outer surface of a vinyl chloride resin pipe has been widely used, and when it is applied to a steel pipe, a method is used in which the pipe is brought into close contact with the inner face of the pipe by utilizing radial expansion or the like (for example, Japanese Patent Publication No. -69057).

[0003] Vinyl chloride resin is excellent in both durability and mechanical properties. However, there is a concern that it may pollute the environment during disposal, and many proposals have been made for the replacement of resin and lining. It has been done.

[0004] For example, Japanese Patent Publication No. Sho 60-21055 discloses that a sheet is extruded to a size having a predetermined size, that is, an outer circumference equal to or slightly longer than the inner circumference of an object to be lined, and having a similar shape. The crosslinked heat-softening polymer is heated above its melting temperature, passed through a deforming die, cooled immediately, and reduced in size so that it can be inserted without contacting the inner peripheral surface of the object to be lined. A method for producing a heat-recoverable pipe, characterized in that the deformation is fixed to a non-similar size. Electron beam irradiated polyethylene is described as an example of the crosslinked polymer.

Japanese Patent Application Laid-Open No. Sho 59-71821 discloses that a synthetic resin tube provided with a thermal expansion property is introduced into a crosshead die while being kept at a predetermined temperature higher than room temperature and lower than a softening temperature. The heat-sensitive adhesive on the film is extruded from the die into a cylindrical shape, and the entire surface of the synthetic resin tube is coated in close contact with the entire surface of the synthetic resin tube to form a coated tube.Then, the coated tube is inserted into a metal tube and then heated and expanded to form an inner surface of the metal tube. A method for manufacturing a synthetic resin-lined pipe characterized by being closely attached is described.

[0006]

However, known coating materials for metal pipe linings impart thermal expansion properties by stretching, but the stress required for stretching the pipe is large, and the stretching operation is not always easy. However, there is a problem that productivity is low. Needless to say, if the stretching temperature is increased, the stress required for stretching can be reduced, but in this case, the tendency that the bending at an angle does not contribute much to the thermal expansion property is recognized.

Further, the synthetic resin used for the coating material for the known metal pipe lining does not have an adhesive property to the metal pipe, and therefore, a special adhesive is applied to the resin pipe or extruded. This requires a special operation to perform the process, which involves a large number of steps, and there is a point to be improved in terms of cost and productivity.

A metal pipe such as a water supply pipe or a gas pipe using the above-described metal pipe is generally used while being buried in the soil. Corrosion of metal pipes buried in the soil progresses due to long-term use, and inspection and repair or replacement of the pipes themselves is required at regular intervals.

On the other hand, in order to prevent the inner surface corrosion of the metal tube,
Lining metal pipes lined with resin are also widely used. As such a lining resin, those in which an adhesive layer is provided on the outer surface of various types of pipes have been widely used, and when applied to a steel pipe, the pipe is brought into close contact with the inner surface of the pipe by utilizing radial expansion or the like. Method (for example, 4-6)
No. 9057).

However, whether the underground pipe is to be repaired or replaced, it is necessary to dig the ground, so that it is necessary to perform the work in a place where digging is difficult, the labor and time required for digging, and the cost for that. In consideration of such factors, a construction method capable of performing construction in a buried state is desired.

[0011] Accordingly, an object of the present invention is to provide a low stretching stress even at a relatively low temperature, easy stretching operation, excellent productivity and satisfactory restoration when lining various pipes. It is an object of the present invention to provide a resin pipe which has good properties and exhibits strong adhesion to various pipes, and a lining covering material or a pipe repair resin pipe using the resin pipe. Another object of the present invention is to provide a coating method using the lining coating material. Still another object of the present invention is to solve the problems of the conventional pipe repair method, using the above-mentioned pipe pipe for resin repair, and keeping the pipe buried in the soil as it is. An object of the present invention is to provide a pipe repair method capable of performing repair by an inner surface coating.

[0012]

According to the present invention, there is provided a resin pipe in which at least one layer is an ionomer. It goes without saying that the resin pipe of the present invention may be composed of a single layer of ionomer. However, the resin pipe may have a laminated structure of two or more layers. A co-extruded laminate of an outer layer of ionomer and an inner layer of cross-linked or non-cross-linked polyethylene; C. a co-extruded laminate of an outer layer of an acid-modified ethylene resin or a silane-modified olefin resin and an inner layer of an ionomer; Examples include a co-extruded laminate of an outer layer of an acid-modified ethylene-based resin or a silane-modified olefin-based resin, an intermediate layer of an ionomer, and an inner layer of crosslinked or non-crosslinked polyethylene. The resin pipe of the present invention may be unstretched or stretched, but is preferably a stretched resin pipe in terms of thermal expansion.

According to the present invention, a coating material for a pipe lining used by bonding the above-mentioned resin pipe to the inner surface of the pipe, and this coating material for a pipe lining are inserted into the inside of the pipe, and the coating material is heated. A method of coating a tube is provided, characterized in that the tube is expanded downward and thermally bonded to an inner surface of the tube.

According to the present invention, further, the above resin pipe is
The resin pipe for pipe repair to be drawn into the pipe to be repaired having an inner diameter larger than the outer diameter of the resin pipe and used in close contact with the inner surface of the pipe, and this resin pipe for pipe repair, into the pipe buried in the soil Then, a heating medium is introduced into the resin pipe to expand the resin pipe at a temperature equal to or higher than the glass transition point (Tg) of the resin pipe and equal to or lower than the melting point (Tm) + 50 ° C. A method for repairing a pipe characterized in that the pipe is fitted to each other is provided.

In this resin pipe for repairing a pipe, the resin pipe comprises: a. Stretching stress at 70 ° C is 1 to 4MP
consisting of the ionomer of a, b. A drawn pipe; c. Having an outer diameter of 1/3 to 2/3 of the inner diameter of the tube; d. When the ratio of the outer diameter _{r 2} of the inner diameter _{r 1} and the resin pipes of the pipe and _{r =} r 2 / _{r 1,} 0.1 r
Having a thickness of 5 to 5r (mm), e. Having a recess in the outer wall extending in the axial direction or the spiral direction for venting air; f. It is preferably a flexible pipe having a bellows extending in the circumferential direction or the spiral direction. In this pipe repair method, the heat medium is preferably hot air or hot water.

[0016]

DETAILED DESCRIPTION OF THE INVENTION [Resin Pipe] In the present invention, an ionomer is defined as an ion-crosslinked ethylene-based copolymer. In general, ionomers are copolymers derived from ethylene and ethylenically unsaturated carboxylic acids, or even other ethylenically unsaturated monomers, with a cation,
In particular, it is known as neutralized with a metal cation.

The present invention is based on the finding that a resin pipe made of an ionomer is particularly suitable for use as a coating material for the inner lining of a pipe.
Unstretched ionomer resin pipes have low stress in pipe expansion even at relatively low temperatures, easy expansion operation, excellent workability, and the ionomer itself has strong adhesion to the pipe. It is based on the knowledge of showing power. In addition, in the case of using an ionomer drawn pipe, in addition to the above-mentioned adhesive properties, the drawing stress is small, the drawing operation is easy, and the productivity of the drawn pipe is excellent. In this method, satisfactory restoration properties are obtained when lining a pipe, so that the occurrence of residual strain due to thermal expansion is suppressed.Therefore, dimensional stability over a long period of use and retention of adhesive strength to the pipe can be obtained. It is based on knowledge.

See Table 1 in Experimental Example 1 described below.
Table 1 shows known vinyl chloride resins (PVC), low density polyethylene (LDPE) and ionomers A and B.
With respect to (Table 3), the results obtained by measuring the stretching stress while changing the stretching temperature are described. According to the results, both ionomers were compared to PVC and LDPE,
The stretching stress at a temperature of 70 ° C. or more is quite small, indicating that the stretching workability is remarkably excellent. This means that the resin pipe is not only advantageous in terms of workability and productivity but also excellent in terms of characteristics of the resin pipe. That is, since stretching can be performed with relatively small stress,
There is no stretching unevenness, the orientation is uniform, and this pipe has no microcracks or pinholes due to overstretching, indicating that it has excellent corrosion resistance.

Also, see Table 2 in Experimental Example 2 to be described later. Table 2 shows that the same PVC, LDPE, ionomer B, and ionomer C (Table 3) as in Table 1 were used.
The results of measuring the restoration rate after heating the stretched product at a temperature of from about 90 ° C. to 90 ° C. are shown. According to this result, the restoration ratio by heating the stretched ionomer is almost 100%, and it is understood that the restoration ratio is excellent.

Generally, the resilience of a stretched polymer largely depends on the shape memory of the polymer, and the presence of a crosslinked structure in radiation-crosslinked polyethylene is a typical example. It is understood that the excellent resilience of the stretched ionomer is due to the shape memory of the polymer, but the ionomer has a special molecular structure in which the ethylene-unsaturated carboxylic acid copolymer chain is ionically cross-linked with a cation. This unique crosslinked structure seems to contribute to excellent stretchability and resilience.

In addition, ionomers have the advantage that they have excellent thermal adhesion to various metals and other resins. For example, the bond strength between an ionomer (100 μm thick) and steel is 65 N / 25 m in a 90 ° peel test.
It is on the order of m width and has outstanding adhesive strength among general-purpose resins. This is presumably because the above-mentioned crosslinked structure also contributes to an increase in affinity with metal and an increase in adhesive strength. In addition, the ionomer has a large adhesive force with other resins, and is particularly compatible with other ethylene-based polymers, which enables the ionomer to be used in a laminate with another resin. Further, as widely used as a skin material of a golf ball, an ionomer is excellent in tear resistance and impact resistance, and also excellent in protecting the inner surface of a tube.

Referring to FIG. 1 for explaining an example of a method for manufacturing an ionomer resin pipe of the present invention, the ionomer resin kneaded by an extruder 1 is extruded into a cylindrical extrudate 2 through a ring-shaped die orifice of the extruder. The cylindrical extrudate 2 is forcibly passed through the sizing die 3 by being taken up by the take-up machine A, and is formed into a predetermined shape and dimensions. A water tank A (vacuum water tank) is provided between the sizing die 3 and the take-off machine A, and the extrudate 4 formed by the sizing die 3 is:
In the water tank A, it is cooled and solidified under the condition that the expansion tension due to the vacuum is applied.

A take-up machine B is provided in front of the take-up machine A via a water tank B and a water tank C. The take-up machine B is driven at a higher speed than the take-up machine A, and the water tank B contains water (heat medium) heated to the stretching temperature, while the water tank C contains water for normal cooling. Is housed. Thus, the pipe 5 from the take-up machine A is
In the water tank B, the drawing pipe 6 is uniaxially stretched at a magnification corresponding to the ratio of the pulling speed of the pulling machine B / the pulling speed of the pulling machine A (radial contraction also occurs at the same time). Cooled and stabilized. The stabilized pipe 7 is cut into a predetermined size by a cutter, and becomes a coating material for pipe lining. Note that the manufacturing method shown in FIG. 1 is for manufacturing a drawn resin pipe, and when used as an undrawn resin pipe, the drawing speed of the drawing machine B is set to be the same as that of the drawing machine A. Can be manufactured.

In order to manufacture a resin pipe having a multilayer structure, the number of extruders corresponding to the type of resin is used, each resin is kneaded in the extruder, and then combined by a multilayer multiplex die to form a layer through an orifice. Extrusion and the same molding operation as described above may be performed.

FIG. 2A shows several examples of the cross-sectional structure of the resin pipe of the present invention. FIG. 2A shows an example in which the resin pipe 10 is formed of a single-layer ionomer 11, and FIGS.
Shows an example in which the resin pipe 10 has a multilayer structure. In the case of a multilayer structure, at least one of the layers only needs to include the ionomer layer. For example, a preferred resin pipe 10 having a multilayered structure comprises (B) a co-extruded laminate of an outer layer 11 of an ionomer and an inner layer 12 of a crosslinked or non-crosslinked polyethylene, and (C) an acid-modified ethylene-based resin or silane-modified. A co-extruded laminate of an outer layer 13 of an olefin-based resin and an inner layer 11 of an ionomer;
(D) a co-extruded laminate of an outer layer 13 of an acid-modified ethylene-based resin or a silane-modified olefin-based resin, an intermediate layer 11 of an ionomer, and an inner layer 12 of a crosslinked or non-crosslinked polyethylene. Of course, it is not limited to these examples.

The ethylene-unsaturated carboxylic acid copolymer serving as the base polymer of the ionomer includes 88 to 98 mol%, particularly 90 to 97 mol% of an ethylene component, 2 to 12 mol% of an unsaturated carboxylic acid component, In particular, 3 to 10 mol%, and 0 to 15 mol%, especially 0 to 12 mol% of other unsaturated monomer components other than ethylene and unsaturated carboxylic acid.
The copolymerization may be carried out at a ratio of mol%. Further, as long as the sum satisfies the above conditions, two or more kinds of unsaturated carboxylic acid component units may be used.

As the unsaturated carboxylic acid component, for example,
Acrylic acid, methacrylic acid, ethacrylic acid, fumaric acid,
Examples thereof include maleic acid, maleic acid monomethyl ester, maleic acid monoethyl ester, and maleic anhydride, and acrylic acid or methacrylic acid is particularly preferable.

Other unsaturated monomer components include, for example, acrylic esters such as methyl (meth) acrylate, ethyl (meth) acrylate, isobutyl (meth) acrylate, and n-butyl (meth) acrylate; Examples include methacrylic acid esters and vinyl acetate.

Examples of the metal cation in the ethylene-unsaturated carboxylic acid copolymer ionomer include alkali metals such as lithium, sodium and potassium, alkaline earth metals such as magnesium and calcium, and transition metals such as zinc. The degree of neutralization by metal ions is not particularly limited, but those having an average degree of neutralization of 10% or more, preferably 20 to 80% are suitable.

As the ionomer, 190 ° C., 2
Melt flow rate at 160 g load is 0.1 to 5
It is preferable to use one having 0 g / 10 min, especially about 0.2 to 30 g / 10 min. Also, 70 ° C of ionomer
Stretching stress of 1 to 4 MPa, preferably 1.5
It is preferably from 3.5 to 3.5 MPa. Stretching stress is 4
When the pressure exceeds MPa, not only the expansion operation becomes difficult, but also the operation of drawing the resin pipe into a pipe having a curved pipe part becomes particularly difficult. On the other hand, if the stretching stress is less than 1 MPa, elongation occurs during the operation of drawing in the resin pipe, which is not preferable.

It should also be understood that in the present invention, a plurality of ionomers can be used in a blended form or in a laminated form. Ionomers are broadly classified into two types: hard ionomers containing no unsaturated ester units and soft ionomers containing unsaturated ester units. These two types of ionomers can be blended or laminated. Can be used.

The polyethylene used for forming the multi-layer pipe in combination with the ionomer includes low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), and linear polyethylene. Ultra low density polyethylene (LULD
PE) and the like are used. These polyethylenes are radically crosslinkable, and when melt-extruded in combination with a radical crosslinking agent, they produce crosslinked polyethylene. As the radical crosslinking agent, an organic peroxide is appropriate, and it is appropriate to use 0.1 to 5 parts by weight of a radical crosslinking agent (initiator) per 100 parts by weight of polyethylene.

As the radical crosslinking agent (initiator), all the radical initiators used in this kind of crosslinking treatment can be used. For example, organic peroxides, organic peresters, and the like can be used.
For example, benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5-di (peroxidebenzoate) hexyne-3, 1,4-bis (tert-butylperoxyisopropyl) benzene, lauroyl peroxide, tert-butyl peracetate, 2,5-dimethyl-
2,5-di (tert-butylperoxy) hexyne-3,
2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, tert-butylperbenzoate, tert-
Butyl perphenyl acetate, tert-butyl perisobutyrate, tert-butyl per-sec-octoate,
There are tert-butyl perpiparate, cumyl perpiparate and tert-butyl perdiethyl acetate, and other azo compounds such as azobisisobutyronitrile and dimethylazoisobutyrate. In order to effectively perform crosslinking under the conditions of melt-kneading polyethylene, the half-life temperature of the radical initiator is desirably in the range of 100 to 200 ° C.

Further, the above polyethylene can be crosslinked with silane. That is, a silane compound that can be subjected to a grafting treatment and a crosslinking treatment can be blended into polyethylene, grafted in the presence of the above radical initiator, and then crosslinked by hydrolysis. As the radical polymerizable organic group,
Examples include an ethylenically unsaturated hydrocarbon group such as a vinyl group, an allyl group, a butenyl group, and a cyclohexenyl group, and an alkyl group containing an ethylenically unsaturated carboxylic ester unit such as an acryloxyalkyl group and a methacryloxyalkyl group. However, vinyl groups are preferred. Examples of the hydrolyzable organic group include an alkoxy group and an acyloxy group. Suitable examples of the silane compound include, but are not limited to, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris (methoxyethoxy) silane, and the like. In the latter case, it is preferable that the silane compound is present in an amount of 0.1 to 10 parts by weight, particularly 0.2 to 5.0 parts by weight, and the radical initiator is present in a catalytic amount per 100 parts by weight of the polyethylene.

The acid-modified ethylene-based resin or silane-modified olefin-based resin used in the formation of the multi-layer pipe in combination with the ionomer is used when the resin pipe of the present invention is used as an inner coating material or a repair material for the pipe. It serves to adhere to the pipe and is used for the outer layer in contact with the pipe. The acid-modified ethylene-based resin is a graft-modified polyethylene having a graft amount of an unsaturated carboxylic acid or a derivative thereof of 0.01 to 10% by weight, preferably 0.1 to 5% by weight. Examples of the polymer include the polyethylene exemplified above, and a copolymer of ethylene with a vinyl ester such as α, β-unsaturated carboxylic acid ester such as acrylic acid ester and methacrylic acid ester and vinyl acetate. .
As the unsaturated carboxylic acid, those exemplified above are suitable, but maleic acid, nadic acid (registered trademark) or acid anhydrides thereof are preferable. Other examples of the acid-modified ethylene-based resin include the ethylene-unsaturated carboxylic acid copolymers exemplified above, that is, those not neutralized with metal ions.

Further, the silane-modified olefin resin used in combination with the ionomer to form a multilayer pipe has a grafting amount of the unsaturated silane compound of 0.01 to 5% by weight.
It is preferably a graft-modified olefin-based resin in an amount of 0.02 to 3% by weight. As an olefin polymer serving as a base of such a silane-modified olefin resin,
Homopolymers of olefins having 2 to 8 carbon atoms such as ethylene, propylene, 1-butene and 1-hexene, and α, β such as acrylates and methacrylates
-Selected from vinyl esters such as unsaturated carboxylic acid esters, vinyl acetate and vinyl propionate, epoxidized unsaturated hydrocarbons, epoxidized unsaturated ethers, and epoxy group-containing olefin copolymers such as epoxidized unsaturated esters. And at least one copolymerized monomer and the olefin.

As long as the graft concentration of the unsaturated silane compound satisfies the above specified value, a mixture of a silane-graft-modified olefin-based resin and another non-silane-grafted thermoplastic resin can be used. Representative examples of such thermoplastic resins include high-, medium-, or low-density polyethylene, vinyl esters such as ethylene and vinyl acetate, unsaturated carboxylic esters such as acrylates and methacrylates, butene, hexene. And the like, copolymers with α-olefins, such as, homo, random, and block polypropylene.

The unsaturated silane compound used in the synthesis of the silane-modified olefin resin is a silane compound having an unsaturated group and a hydrolyzable group, and specific examples thereof include vinyltrimethoxysilane and vinyltriethoxy. Examples thereof include vinyl silanes such as silane, vinyl (β-methoxyethoxy) silane and vinyl triacetoxy silane, and acrylic silanes such as acryloxy propyl trimethoxy silane and methacryloxy propyl trimethoxy silane.

The resin pipe of the present invention contains resin compounding agents known per se, such as fillers, coloring agents, heat stabilizers, weather stabilizers, antioxidants, antioxidants, antistatic agents, metal soaps, and the like. A well-known resin compounding agent such as a lubricant such as wax, a modifying resin or rubber, and sulfur for chlorine-resistant water can be compounded according to a formulation known per se.

The drawn pipe used in the present invention, which comprises at least an ionomer layer, varies depending on the inner diameter of the pipe to be formed and the required thickness of the coating.
Preferably, it has a thickness of 1 to 5.0 mm. Further, the thickness of the ionomer layer relative to the total thickness of the pipe is preferably 50% or more, particularly preferably 60% or more.

When producing a drawn pipe, the drawing temperature of the extrudate varies depending on the type of the ionomer, but is generally in the range of 50 to 100 ° C., particularly preferably 55 to 95 ° C., and is preferably in the uniaxial direction. Is preferably in the range of 1.02 to 3 times, particularly 1.04 to 2.5 times. Further, the degree of diameter reduction accompanying stretching, that is, the ratio of diameter after stretching / diameter before stretching is preferably in the range of 0.50 to 0.98, particularly 0.6 to 0.96.

[Coating material for pipe lining and method thereof] In order to use the resin pipe of the present invention for coating a pipe as a coating material for pipe lining, the resin pipe is inserted into the inside of the pipe, and the coating material is heated. And heat bonded to the inner surface of the tube.

The heating of the resin pipe can be performed directly or indirectly. For example, in the former case,
The tube into which the resin pipe is inserted is placed in a heating oven, and the whole may be heated.In the latter case, the tube is heated by electromagnetic induction,
Heat bonding may be performed by sequentially heating from one end to the other end by high-frequency induction heating, hot air blowing, gas burner heating, or the like.

When the resin pipe is a stretched pipe, the expansion is performed by utilizing the thermal expansion property inherent in the stretched pipe. In order to supplement the expansion property, hot air may be blown into the pipe. it can. Of course, when the resin pipe is an unstretched pipe, the expansion of the pipe depends on the fluid pressure of the heat medium. For this purpose, both ends of the resin pipe may be closed in advance.

[Pipe Repair Method] In the present invention, it is possible to repair the pipe buried in the soil by coating the inner surface of the pipe as it is by applying the above-mentioned pipe lining coating material and coating method. In FIG. 3 for explaining the principle of the repair method of the present invention, in a step (A), a towing line 23 for drawing an ionomer resin pipe is passed through a pipe 22 buried in the soil 21 and requiring repair. In the step (B), an ionomer resin pipe 24 having an outer diameter smaller than the inner diameter of the pipe 22 is prepared, and the traction cable 23 is connected to the resin pipe 24.
By pulling the tow rope 23
Until one end of the resin pipe 24 comes out of the end of the pipe 22,
The resin pipe 24 is pulled in. In the step (C), a wet or dry heating medium 25 is supplied from the other end of the resin pipe 24.
Is blown into the resin pipe 24, and the resin pipe 24 is heated to a temperature equal to or higher than the glass transition point (Tg) and the melting point (Tm) +
Heat to a temperature below 50 ° C. and expand. As a result, as shown in step (D), a protective coating 26 of the ionomer resin is firmly adhered to the inner surface of the pipe 22, and the pipe 22 is repaired effectively while being buried in the soil. .

In the resin pipe used in the repair method of the present invention, the resin pipe having an outer diameter of 1/3 to 2/3 of the inner diameter of the pipe is advantageous in terms of workability of drawing into the pipe. . The resin pipe is used, when the ratio of the outer diameter _{r 2} of the inner diameter _{r 1} and the resin pipes of the pipe and _{r =} r 2 / _{r 1,} 0.1 r to 5r of (mm), especially 0.2r to 4 Having a thickness of 0.5r (mm) is advantageous in terms of protecting the inner surface of the tube and pulling into the tube. When the thickness exceeds the above range, if a curved pipe portion, for example, an elbow portion at an angle of 90 ° exists in a part of the pipe to be repaired, the resin pipe tends to be not smoothly drawn in. If the thickness is less than the above range, the inner surface protection of the pipe may be insufficient, so that the thickness is preferably within the above range.

In the repair method of the present invention, a flexible tube having a bellows extending in a circumferential direction or a spiral direction can be used as the resin pipe. In this case, the resin pipe can be smoothly drawn through the curved pipe portion. Will be done.

Further, when the resin pipe is heated and expanded, it is important that the air in the pipe is smoothly discharged to the outside and that the resin pipe is in close contact with the resin pipe without any gaps due to bubbles of residual air. It is preferable that the outer wall has a concave portion for venting air extending in the direction or spiral direction.

In order to use the ionomer resin pipe of the present invention for coating and repairing a pipe, as described above, the ionomer pipe is inserted into the pipe, and the resin pipe is expanded under heating to be thermally bonded to the inner surface of the pipe. Let it. The heating of the ionomer resin pipe can be performed by a dry method or a wet method using a heat medium. Hot air heated by a gas burner or the like or hot water or hot water may be blown from one end of the resin pipe, and may be sequentially heated and expanded from one end to the other end while performing thermal bonding.

The expansion of the resin pipe is performed in the same manner as the above-mentioned coating method in the case of a stretched pipe by utilizing the inherent thermal expansion property of the stretched pipe. Hot air can be blown into the interior. Of course, when the resin pipe is an unstretched pipe, the expansion of the pipe depends on the fluid pressure of the heat medium. For this purpose, both ends of the resin pipe may be closed in advance.

The pipes covered by the present invention include buried pipes such as sewer pipes, civil engineering and agricultural pipes, water pipes, gas pipes, and the like.
Internal pressure pipes, such as a hot water supply pipe, a hydraulic pneumatic pipe, and a pneumatic pipe, are mentioned. The material of the tube is generally steel or cast iron, but in addition to a metal tube such as a galvanized tube or a copper tube, a light metal tube such as aluminum or its alloys, a thermosetting resin tube, Of course, it can be applied to a glass tube and a wooden tube.

[0052]

EXPERIMENTAL EXAMPLE The present invention will be further described by the following example. [Experimental Example 1] Stretching stress (100% modulus) Measuring method: Sample (10 × 10
0 to 1 mm) between 50 to 100 mm (100 mm)
%) Was measured. For confirmation, the elongation between marked lines (elongation between chucks) of the sample immediately after the measurement was also measured.

[0053]

[Table 1] Stretching stress (numbers in parentheses in the table indicate elongation between marked lines) Unit: MPa measurement temperature PVC LDPE ionomer A ionomer B 23 ° C> 50 8.9 (71%) 13.5 (95%) 13.5 (106% ) 70 ℃> 50 4.9 (105%) 2.6 (120%) 2.6 (127%) 80 ℃> 50 4.1 (100%) 1.6 (118%) 1.6 (125%) 90 ℃ 12.3 (98%) 3.2 (110% ) 0.8 (107%) 1.0 (110%) 100 ℃ 5.9 (110%) 1.1 (95%) 0.2 (100%) 0.3 (100%) 110 ℃ 4.0 (105%) 0.2 (90%) 0.05 (80%) 0.1 (90%) 120 ℃ 3.8 (100%) 130 ℃ 2.6 (97%)

[Experimental example 2] Restorability Measuring method: A sample similar to the one in which the stretching stress was measured was stretched 140%, and after cooling with cold water, it was evaluated how much the film was restored in one hour in oven heating. 70 mm between marked lines.

[0055]

[Table 2] Restoration rate% of the distance between the marked lines (the number in parentheses is the stretching rate% between the marked lines at the time of stretching) Restoration temperature Stretching temperature sample 90 ° C 100 ° C 110 ° C 70 ° C PVC LDPE 99 (124) 98 (125) 99 (123) Ionomer B 99 (131) 98 (131) 99 (134) Ionomer C 99 (128) 99 (128) 99 (131) 80 ° C PVC 98 (139) 99 (140) 95 (142 ) LDPE 99 (128) 98 (131) 99 (131) Ionomer B 98 (138) 96 (142) 98 (137) Ionomer C 98 (135) 96 (136) 97 (135) 90 ° C PVC 99 (145) 99 (145) 98 (143) LDPE 98 (137) 96 (135) 95 (147) Ionomer B 93 (141) 96 (145) 97 (146) Ionomer C 96 (137) 91 (155) 95 (141)

Evaluation result: almost 1 in all samples
00% restored. (70-90 ° C.) Restorability was measured for the width and thickness of the test piece as well as between the marked lines.
Restored.

Hereinafter, the present invention will be described specifically with reference to examples. In addition, the composition and physical properties of the raw resin used in the examples and comparative examples, and the evaluation method of the obtained resin-lined steel pipe are as follows.

1. Resin raw material for coating material 1.1. Ethylene / methacrylic acid copolymer ionomer Ionomer described in Table 3 1.2. Ethylene / methacrylic acid copolymer (EMAA) Methacrylic acid content 12% by weight Melt index 7g / 10min 1.3. Low-density polyethylene (LDPE) Low-density polyethylene Mirason 401 manufactured by Mitsui Chemicals, Inc. Melt index 1.6 g / 10 min Density 918 kg / m ³ 1.4. Silane-modified ethylene copolymer composition The silane-modified polyethylene copolymer composition used for the outer layer as an adhesive for various pipes is ethylene / ethyl acrylate (copolymer weight ratio 81/19, melt index 25 g / 10 min) 100 0.4 parts by weight of γ-methacryloxypropyl trimethoxysilane to 2,
0.1 part by weight of 5-dimethyl-2,5-bis (tert-butylperoxy) hexane was added, and this mixture was added to 30 parts.
It was synthesized by kneading at a resin temperature of 220 ° C. using a mm single screw extruder.

[0059]

[Table 3] Ionomer Ionomer Ionomer Ionomer A BCD methacrylic acid content 10 10 9 10 (wt%) Butyl acrylate 0.0010 content (wt%) Mediumness 70 50 20 70 (%) Metal cation zinc sodium zinc Zinc Melt Index 11 5 1 (g / 10min)

2. Evaluation method of resin-lined steel pipe 2.1. Shear adhesive stress A test piece with a width of 20 mm was cut out from the resin-lined steel pipe, and in accordance with the Japan Water Works Association Standard JWWA-K116,
The force required to push out the resin lining portion with the backing metal was measured, and the value obtained by dividing by the contact area of the resin lining portion was determined as the shear adhesive stress (measuring temperature 23 ° C.). 2.2. Durability test A resin-lined steel pipe was cut out of a length of 1 m from an arbitrary place, and a cycle test in which one cycle of immersion in 80 ° C hot water for 2 hours and immersion in 20 ° C hot water for 2 hours was repeated 60 times, and then 2.1. According to the method described in the above section, the shear adhesive stress was measured.

Example 1 Using an extruder 1 shown in FIG.
The ionomer B was extruded at a resin temperature of 170 ° C. and cooled in a vacuum water tank A provided with a sizing die 3 to produce an ionomer tube 4 having a primary outer diameter of 22 mm and a thickness of 1 mm. After passing through the take-up machine A, the ionomer tube 4 is heated to a temperature of 80 ° C. by the water tank B, and stretched by setting the speed ratio between the take-up machine B and the take-up machine A to 1.18.
After cooling and solidifying to room temperature, it was cut into a predetermined length by a cutter. The secondary outer diameter of the obtained ionomer tube 7 is 2
It was 0 mm. These operations were performed continuously. When the obtained ionomer tube 7 was immersed in hot water at 90 ° C. for 2 minutes, the outer diameter expansion rate was 10% and the lengthwise shrinkage rate was 17%, showing good shape resilience. Further, the ionomer pipe 7 is inserted into a carbon steel pipe for piping (inner diameter 21.6 mm),
The steel pipe was heated from one end to the other end by a burner so that the surface temperature of the steel pipe became 150 ° C. on average. Table 4 shows the performance evaluation results of the obtained ionomer-lined steel pipe. In addition, since the ionomer tube 7 has good transparency, an interesting advantage that the adhesive interface between the coating material and the steel tube can be visually observed, and even if air traps occur at the interface, it can be visually detected. Was found.

Example 2 As a cross-sectional structure of a covering material for lining, in a multilayer structure shown in FIG. 2C, co-extrusion in which an ethylene-methacrylic acid copolymer (EMAA) is an outer layer 13 and an ionomer B is an inner layer 11 is shown. Stretching with a primary outer diameter of 22 mm, a thickness of 1 mm, and a secondary outer diameter of 20 mm was carried out in the same manner as in Example 1 except that the laminated tube was manufactured using a multilayer multiple die and the thickness ratio between the outer layer 13 and the inner layer 11 was 10/90. A pipe was prepared, and a resin-lined steel pipe was prepared in the same manner as in Example 1. Table 4 shows the performance evaluation results of the obtained resin-lined steel pipe.

Example 3 As the cross-sectional structure of the lining covering material, in the multilayer structure shown in FIG. 2D, an ethylene / methacrylic acid copolymer (EMAA) was used as the outer layer 13, the ionomer B was used as the intermediate layer 11, and the low density was used. Polyethylene (LDP
E) The co-extruded laminated tube having the inner layer 12 is a multilayer multiplex die, and the thickness ratio of the outer layer 13, the intermediate layer 11, and the inner layer 12 is 10 /.
Except for the fact that it was manufactured as 80/10, in the same manner as in Example 1, the primary outer diameter was 22 mm, the thickness was 1 mm, and the secondary outer diameter was 20 m
m, and a resin-lined steel pipe was prepared in the same manner as in Example 1. Table 4 shows the performance evaluation results of the obtained resin-lined steel pipe.

Comparative Example 1 A low-density polyethylene (LDPE) containing 0.5 parts by weight of dicumyl peroxide was used in place of ionomer B, and was extruded at a resin temperature of 220.degree. An attempt was made to produce a drawn polyethylene tube. However, since the stretching stress of the crosslinked polyethylene was too large, stretching could hardly be performed even if the temperature of the water tank B was raised to 100 ° C.

Example 4 The cross-sectional structure of the lining covering material was the same as the multilayer structure shown in FIG. 2C except that the silane-modified polyethylene copolymer composition was used as the outer layer 13 and the ionomer A was used as the inner layer. As in Example 2,
A drawn tube having a primary outer diameter of 22 mm, a thickness of 1 mm, and a secondary outer diameter of 20 mm was prepared, and a resin-lined steel pipe was prepared in the same manner as in Example 1. Table 4 shows the performance evaluation of the obtained resin-lined steel pipe.

Example 5 A stretched tube (ionomer tube 7) having a primary outer diameter of 22 mm, a thickness of 1 mm, and a secondary outer diameter of 20 mm prepared in the same manner as in Example 4 was inserted into an aluminum tube having an inner diameter of 21.5 mm. An ionomer-lined aluminum tube was prepared in the same manner as in Example 1. Table 4 shows the performance evaluation of the obtained ionomer lining tube.

[0067]

[Table 4]

Example 6 The ionomer B shown in Tables 3 and 5 was used as the ionomer, and the extruder 1 shown in FIG. 1 was used.
Extruded at a resin temperature of 170 ° C using a sizing die
Cooled in a vacuum water tank A equipped with an outer diameter of 22 mm,
An ionomer tube 4 having a thickness of 1 mm was manufactured. In a state where the ionomer tube 4 was heated to 60 ° C., the ionomer tube 4 was inserted into a carbon steel tube for piping (inner diameter 35.7 mm, total length 1 m) having an angle of 90 ° elbow by using a towing line. Subsequently, after one end is sealed with a clamp, while being heated in an oven at 100 ° C., industrial air (pressure 0.3 MPa) is blown from the other end of the ionomer tube 4 to pressurize the ionomer tube 4.
Was expanded to produce a carbon steel pipe having an ionomer inner surface coating layer. When the thickness of the coating layer of this ionomer-coated steel pipe was measured on test pieces cut out from any 10 places including the elbow portion, 0.65 ±
It was in the range of 0.05 mm thickness, and it was confirmed that the film was uniformly expanded. Further, as an index of gas barrier properties, 5
When the gas permeability of nitrogen gas and oxygen gas was measured for the 0 μm thick blown film,
870, 3550 cc / m ² · d. atm.

[Examples 7 and 8] Example 6 was repeated except that ionomer C or ionomer D shown in Tables 3 and 5 was used instead of ionomer B as the ionomer.
In the same manner as in the above, an ionomer-coated carbon steel pipe was manufactured.
When the thickness of the coating layer of the obtained ionomer-coated steel pipe was evaluated in the same manner as in Example 6, good uniformity of the film thickness was observed in each case. Further, when the gas permeability of nitrogen gas and oxygen gas was measured in the same manner as in Example 6, the ionomer C was measured.
780, 2680 cc / m ² · d. at
m and 1250 and 44 for ionomer D, respectively.
30 cc / m ² · d. atm.

Comparative Example 2 Instead of the ionomer, Table 5
A resin-coated carbon steel pipe was manufactured in the same manner as in Example 6 except that the described 14% EVA was used. The thickness of the coating layer of the obtained resin-coated steel pipe was evaluated in the same manner as in Example 6. As a result, a locally thin portion was observed in the elbow portion and the clamp sealing portion at the tip (average thickness = 0.65 mm). , Thinnest thickness = 0.41 mm). Further, when the gas permeability of nitrogen gas and oxygen gas was measured in the same manner as in Example 6, they were 2260 and 7400 cc / m ² · d. atm, and gas barrier properties were insufficient.

[Comparative Example 3] Instead of the ionomer, Table 5
Except for using the described LDPE, in the same manner as in Example 6,
A resin tube 4 was manufactured. When this resin tube 4 was heated to 60 ° C., it could not be held forward at the 90 ° elbow when inserted into the carbon steel tube.
While being heated to 0 ° C., the tube was inserted into a carbon steel tube using a towing line. After sealing one end with a clamp, even in the operation of performing thermal expansion, it did not expand with industrial air (pressure 0.3 MPa) when heated in an oven at 100 ° C.
By heating and expanding the resin tube 4 in a 130 ° C. oven, a carbon steel tube having an LDPE inner surface coating layer was manufactured. When the thickness of the coating layer of the obtained resin-coated steel pipe was evaluated in the same manner as in Example 6, similar to Comparative Example 2, the occurrence of locally thin portions was observed in the elbow portion and the clamp sealing portion at the tip. (Average thickness = 0.64 mm, thinnest thickness = 0.39 mm). Furthermore, when the gas permeability of nitrogen gas and oxygen gas was measured in the same manner as in Example 6,
1330, 4620 cc / m ² · d. atm.

[0072]

Table 5 Resin Glass transition Melting point ²⁾ Torsional rigidity ³⁾ Temperature ¹⁾ (° C) (° C) (MPa) Ionomer B 50 97 13 Ionomer C 35 98 25 Ionomer D 45 867 14% EVA ⁴⁾ - 25 91 15 LDPE ⁵⁾ -20 109 35 1) The relaxation temperature attributed to micro-Brownian motion of the polyethylene main chain was determined by dynamic viscoelasticity measurement (Macromolecules, 1993, 26 , 752). 2) DSC method 3) According to ASTM D-1043 (test piece: 1 mm press sheet), measurement temperature 60 ° C. 4) Evaflex P-1405 manufactured by DuPont-Mitsui Polychemicals Co., Ltd. (MI = 3.5 g / 10 min, VA content = 14%) 5) Low density polyethylene (described in 1. Resin raw material for coating material)

[0073]

According to the present invention, by providing a resin pipe having at least one layer of an ionomer as a coating material for a pipe lining or a pipe inner surface repairing material, the resin pipe can be expanded even at a relatively low temperature. Stress and stretching stress are small, the expansion operation and stretching operation are easy, and the advantage of excellent workability and productivity is obtained. Uniform, free of defects such as microcracks and pinholes.Satisfactory resilience is obtained when lining pipes, and the generation of residual strain is suppressed. The advantage of exhibiting a stable adhesion is achieved.

According to the present invention, the resin pipe having an outer diameter smaller than the inner diameter of the pipe is drawn into the pipe to be repaired buried in the soil, and thereafter, a heating medium is introduced into the resin pipe so that the resin pipe is heated. The pipe is expanded at a temperature equal to or higher than the glass transition point (Tg) of the resin pipe and equal to or lower than the melting point (Tm) + 50 ° C., and the resin pipe is brought into close contact with the inner surface of the pipe so that the pipe buried in the soil is maintained as it is. It is possible to perform the repair by the inner surface covering, the excavation of the ground is not required, and a great advantage is achieved in terms of labor, time and cost of construction.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a manufacturing process of an ionomer resin pipe.

FIG. 2 is a sectional view showing a sectional structure of a resin pipe.

FIG. 3 is a process diagram of a repair method according to the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) B32B 31/30 B32B 31/30 F16L 1/00 F16L 1/00 J 11/11 11/11 // B29K 33 : 00 B29L 23:00 F term (reference) 3H111 AA02 BA15 BA34 CA47 CB02 CB03 CB04 CB23 CB29 DA26 DB27 4F100 AH06A AK04A AK04B AK04C AK70A AK70B AL06A AL07A BA03 BA07 BA10A BA10B12 J11 EJ05B12 J05 EJ05B12 J05 EJ05B11 AG08 AG10 AH43 AR06 SA13 SC03 SD04 SD11 SG01 SP15 SP21 SP25 SP44

Claims (17)

[Claims] 1. A resin pipe in which at least one layer is an ionomer. 2. The resin pipe according to claim 1, comprising a single layer of an ionomer. 3. The resin pipe according to claim 1, comprising a coextruded laminate of an outer layer of an ionomer and an inner layer of crosslinked or non-crosslinked polyethylene. 4. The resin pipe according to claim 1, comprising a co-extruded laminate of an outer layer of an acid-modified ethylene resin or a silane-modified olefin resin and an inner layer of an ionomer. 5. The resin pipe according to claim 1, comprising a coextruded laminate of an outer layer of an acid-modified ethylene-based resin or a silane-modified olefin-based resin, an intermediate layer of an ionomer, and an inner layer of a crosslinked or non-crosslinked polyethylene. . 6. The resin pipe according to claim 1, wherein the resin pipe is stretched. 7. A coating material for pipe lining, wherein the resin pipe according to claim 1 is adhered to an inner surface of the pipe. 8. A method for coating a pipe, comprising inserting the coating material for a pipe lining according to claim 7 into a pipe, expanding the coating under heating, and thermally bonding the coating to an inner surface of the pipe. . 9. A pipe repair for pulling the resin pipe according to claim 1 into a pipe to be repaired having an inner diameter larger than the outer diameter of the resin pipe, and bringing the pipe into close contact with the inner surface of the pipe. For resin pipe. 10. The resin pipe according to claim 9, wherein the resin pipe is made of an ionomer having a stretching stress at 70 ° C. of 1 to 4 MPa. 11. The resin pipe is one-third to two times the inner diameter of the pipe.
The resin pipe for pipe repair according to claim 9 or 10, which has an outer diameter of / 3. 12. When the ratio of the inner diameter r ₁ of the resin pipe to the outer diameter r ₂ of the resin pipe is r = r ₂ / r ₁ , the resin pipe has a diameter of 0.1.
The resin pipe for pipe repair according to any one of claims 9 to 11, wherein the resin pipe has a thickness of 1r to 5r (mm). 13. The resin pipe for repairing a pipe according to claim 9, wherein the resin pipe has a concave portion for venting air extending in an axial direction or a spiral direction on an outer wall. 14. The resin pipe for pipe repair according to claim 9, wherein the resin pipe is a flexible pipe having a bellows extending in a circumferential direction or a spiral direction. 15. The resin pipe for pipe repair according to claim 9, which is drawn into a pipe buried in the soil,
After that, a heating medium is introduced into the resin pipe so that the resin pipe has a temperature equal to or higher than the glass transition point (Tg) and a melting point (T
m) A method for repairing a pipe, characterized in that the pipe is expanded at a temperature of + 50 ° C. or less and the resin pipe for pipe repair is brought into close contact with the inner surface of the pipe. 16. The pipe repair method according to claim 15, wherein the heat medium is hot air. 17. The pipe repair method according to claim 15, wherein the heat medium is hot water.