JP2710367B2 - Corrosion prevention lining method for pipe inner surface - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a lining method for an inner surface of a pipe in which corrosion resistance is required.

[Conventional technology]

Conventionally, in the case of metal, asbestos, and fume pipes used for pipes for water supply, sewerage, industrial water supply, chemical plants, etc., in order to prevent corrosion of the pipes due to the chemical properties of the internal fluid, an anticorrosion lining layer Is provided. As the anticorrosion lining on the inner surface of the pipe, there has been proposed a cement mortar mixed with an acrylic emulsion resin, a lining method using a glass fiber reinforced plastic, or a method provided with an anticorrosion lining layer using an unsaturated polyester resin mortar.

[Problems of the prior art]

However, although unsaturated polyester resins have a reputation for chemical resistance, they have high shrinkage upon curing and have residual strain, and therefore have a problem in durability under stress. Glass fiber was also tried,
Residual strain due to shrinkage was not sufficient, and a satisfactory one could not be obtained.

In addition, there is a problem that sufficient adhesion cannot be obtained even by the primer treatment because the adhesion to the tube is poor.

[Problems to be solved by the invention]

In view of the above problems, the present invention does not have shrinkage or residual strain due to a resin composition mainly containing an unsaturated polyester resin having excellent chemical resistance on the inner surface of the tube and showing no shrinkage or expansion when cured, and has no residual strain. The purpose of the present invention is to provide an anticorrosion lining method having excellent adhesion.

[Technology to solve the problem]

That is, the anticorrosion lining method for the inner surface of the pipe according to the present invention employs 100 parts by weight of an unsaturated polyester resin, 1 to 100 parts by weight of a thermoplastic resin having compatibility with a crosslinkable vinyl monomer contained in the unsaturated polyester resin, and inorganic material. Alternatively, a curing agent is added to 100 to 1800 parts by weight of an organic filler, and a resin composition exhibiting no shrinkage or expansion during curing is supplied to the inner surface of the rotating tube, and a layer of the composition is centrifugally formed on the inner surface of the tube. Thereafter, the composition is cured, and 100 parts by weight of an unsaturated polyester resin containing a curing agent, and a thermoplastic resin 1 compatible with a crosslinkable vinyl monomer contained in the unsaturated polyester resin. ~ 100 parts by weight are fed to the inner surface of the rotating tube, and a uniform resin layer is formed on the inner peripheral surface.
It is characterized by uniformly spraying 100 to 1800 parts by weight, sinking the filler into the resin liquid layer by centrifugal force, and then curing the resin composition layer which is formed and shows no shrinkage or expansion at the time of curing. is there.

[Action]

The unsaturated polyester resin (A) used in the present invention can be prepared by a conventional method, for example, by using an α, β-unsaturated dibasic acid or a mixture of the same with a saturated dibasic acid and a polyhydric alcohol. A method of heating to 140 to 250 ° C. in an inert gas stream such as carbon dioxide gas and nitrogen gas to cause a condensation reaction, and gradually increasing the temperature according to the degree of reaction progress while distilling the generated water out of the reaction system; a method of heating a β-unsaturated dibasic acid anhydride or a mixture of the same with a saturated dibasic acid anhydride and an oxide in an inert gas stream at 50 to 250 ° C. in the absence of a catalyst or in the presence of a catalyst to cause a reaction, α, β Replacing some or all of the unsaturated dibasic acid or its mixture with a saturated dibasic acid with esters of these acids with lower alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol and / or Alternatively, part or all of the polyhydric alcohol is substituted with an ester of the polyhydric alcohol with a lower fatty acid such as acetic acid, propionic acid, etc., and heated to 140 to 250 ° C. in an inert gas stream in the presence of a transesterification catalyst to cause a condensation reaction. The unsaturated polyester having an acid value of 60 or less and a molecular weight of 1000 or more is obtained according to a method such as gradually increasing the temperature according to the degree of reaction progress while distilling off generated water, alcohol, etc. out of the reaction system. It is a resin that is mutually dissolved with a hydrophilic vinyl monomer. In this case, α,
Examples of the β-unsaturated dibasic acid include maleic acid, halogenated maleic acid, fumaric acid, citraconic acid, itaconic acid, halogenated itaconic acid, and acid anhydrides thereof. , Halogenated phthalic acid, phthalic anhydride, halogenated phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, 3,6-endomethylenetetrahydrophthalic acid, succinic acid, adipic acid, glutaric acid, pimelic acid, cornic acid , Azelaic acid, sebacic acid and the like. If necessary, monobasic acids such as acrylic acid, methacrylic acid, propionic acid, butyric acid, valeric acid, higher fatty acids, benzoic acid, octylic acid and the like, and trimellitic acid, hemimelic acid, trimesic acid, tetramethyl benzol As a modifier, a polybasic acid such as carboxylic acid may be used in combination with the above α, β-unsaturated dibasic acid or a mixture thereof with a saturated dibasic acid. Polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,3-butylene glycol, tetramethylene glycol, 1,6-hexanediol, Pentyl glycol, hydrogenated bisphenol A, ethylene oxide and / or propylene oxide adducts of bisphenol A and the like can be mentioned, and they are used in an amount of substantially equivalent to about 5 to 20 mol% with respect to the acid component. Is done. If necessary, higher fatty acid alcohols such as amyl alcohol, hexyl alcohol, benzyl alcohol, octyl alcohol, nonyl alcohol, and decyl alcohol; monohydric alcohols such as tetrahydrofurfuryl alcohol; glycerin, pentaerythritol, and trimethylolethane Polyhydric alcohols such as trimethylolpropane, trimethylolbutane, sorbit, erythritol, menerythritol and the like can be used in combination with the above-mentioned polyhydric alcohols as a modifier.

As oxides, ethylene oxide, 1,2
-Propylene oxide, alkylene oxides such as epichlorhydrin, methyl glycidyl ether,
Examples thereof include glycidyl ethers such as ethyl glycidyl ether and allyl glycidyl ether, and glycidyl esters such as methyl glycidyl ester, ethyl glycidyl ester, and allyl glycidyl ester.

In preparing the unsaturated polyester, when adopting a method of reacting an α, β-unsaturated dibasic acid anhydride or a mixture of the same with a saturated dibasic acid anhydride with an oxide, the catalyst used is lithium. , Sodium, potassium, magnesium, calcium, strontium,
Barium, aluminum, thallium, lead, titanium,
Zirconium, antimony, zinc, cadmium, tin,
Organic or inorganic salts of metals such as mercury, and esters of these metal acids with alcohols, and the like.
One or more of these can be used effectively in an amount of 5.0 to 0.01%, preferably 1.0 to 0.03%. In the case of employing a method of performing a transesterification reaction, the catalyst used in the above method can be used as it is as the transesterification catalyst used, and in particular, compounds of zinc, tin, antimony, lead, and titanium are used as catalysts. Large and preferred.

The crosslinkable vinyl monomer contained in the unsaturated polyester resin (A) of the present invention copolymerizes with the unsaturated polyester and acts as a crosslinker. For example, styrene, halogenated styrene, α-methylstyrene, vinyl toluene ,
Divinylbenzene, vinyl acetate, acrylic or methacrylic acid, lauryl acrylate, lauryl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate,
Hydroxypropyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate,
Methylol acrylamide, methylol methacrylamide and the like can be mentioned, and one or a mixture of two or more of these monomers is added to 100 parts by weight of the unsaturated polyester.
It can be used in a proportion of up to 300 parts by weight.

The thermoplastic resin (B) used in the present invention includes a polymerizable reactive group CH such as styrene, vinyl chloride, vinyl acetate, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and acrylamide.
_A homopolymer or copolymer of a monomer having ₂ = C <or a monomer other than the above, such as acrylic acid, methacrylic acid, maleic acid, lauryl acrylate, lauryl methacrylate, hydroxyethyl acrylate,
Hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, 2
-Ethylhexyl acrylate, 2-ethylhexyl methacrylate, methylol acrylamide, copolymers with methylol methacrylamide, and the like,
Among these, when the unsaturated polyester resin (A) and the monomer having an unsaturated group are mixed, or when (A) and the monomer having an unsaturated group undergo a curing reaction, they may become optically non-uniform. Such a thermoplastic resin can be used particularly effectively. In addition, styrene / acrylonitrile copolymer, butadiene / acrylonitrile copolymer, saturated polyesters and the like can also be used effectively.

The molecular weight of the thermoplastic resin (B) varies over a wide range,
It is in the range of about 000 to 1,000,000.

The filler (C) used in the present invention is an inorganic or organic fine powder filler such as calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, alumina, clay, kaolin, talc, diatomaceous earth, silica gel, Examples thereof include mica powder, glass fiber powder, asbestos (powder), rock wool, silica powder, sand, and wood powder. One or a mixture of two or more of these fillers can also be used effectively.

In the above description, as is well known, the unsaturated polyester resin (A) has a large shrinkage during curing. When styrene is used as a cross-linking agent, shrinkage is reduced to some extent but is not sufficient, and warpage occurs due to shrinkage,
Due to residual strain, peeling is poor due to poor adhesion to the tube.

The resin composition which exhibits no shrinkage or swelling property upon curing according to the present invention is compatible with 100 parts by weight of the unsaturated polyester resin (A) and the crosslinkable vinyl monomer contained in the unsaturated polyester resin. 1-100 parts by weight of a thermoplastic resin (B) and an inorganic or organic filler (C) 1
It is the one obtained by adding a curing agent to 00 to 1800 parts by weight. This resin composition does not generate residual strain during curing, and its adhesion to the inner surface of the tube is greatly improved by the pressure applied to the inner surface of the tube due to expansion. Cracks can be prevented.
If the amount of the thermoplastic resin is less than 1 part by weight, the shrinkage cannot be sufficiently solved. If the amount exceeds 100 parts by weight, the thermoplastic resin is separated from the polymerizable vinyl monomer and the storage stability of the liquid is poor, and This causes inconvenience of interlayer separation during construction. In addition, when a filler is added, it is difficult to form a uniform composition, so that it is not always possible to mold with a uniform material. According to the present invention, it has been found that the adhesion is improved by centrifugal molding and curing the resin composition. Since the centrifugal force is proportional to the angular velocity of the rotating body and the mass of the object, it is advantageous that the centrifugal effect of the floating filler present in the liquid has a large specific gravity. This centrifugal force is usually formed with a force several tens of times the gravity. When the addition amount of the inorganic or organic filler is set to 100 to 1800 parts by weight, if the amount is less than 100 parts by weight, the pressure applied to the tube wall at the time of centrifugal molding is small and sufficient adhesion cannot be obtained. This is because the concentration of the filler at the interface of the tube wall increases and the adhesion decreases, and the viscosity of the composition increases, making it difficult to perform lining molding.

In the case of centrifugal molding, it is easier to form a uniform lining layer if the viscosity is low. In molding, a mixture obtained by mixing a filler into the resin composition is loaded on the inner surface of the rotating body of the pipe, or (A)
The composition of (B) may be applied to the inner surface of the pipe to form a uniform lining liquid layer, and the filler powder may be sprinkled from the liquid layer to settle the filler in the resin liquid layer by centrifugal force.

Hereinafter, the present invention will be described in more detail with reference to experimental examples, examples, and comparative examples.

Experiment 1 A four-necked flask equipped with a thermometer, a partial condenser, a total condenser, an inert gas inlet tube, and a stirrer was charged with 78.5 g of maleic anhydride, 33.2 g of isophthalic acid, and 80 g of propylene glycol.
A dehydration-condensation reaction was performed at 00 ° C. to obtain an unsaturated polyester having an acid value of 30, and 55 parts of the polyester was mutually dissolved with 45 parts of styrene together with 0.02 part of hydroquinone to obtain a resin (I).

Experiment 2 To the same flask used in Experiment 1, phthalic anhydride 74
g, maleic anhydride 49 g and propylene glycol 80 g
And subjected to a dehydration-condensation reaction at 200 ° C. in an inert gas atmosphere to obtain an unsaturated polyester having an acid value of 40. 60 parts of the polyester and 0.01 part of hydroquinone were mutually dissolved together with 40 parts of styrene to obtain a resin (II).

Experiment 3 A four-necked flask equipped with a thermometer, a stirrer, a dropping device, a cooling device, an inert gas inlet tube, and a reflux condenser, 294 g of maleic anhydride, 1,036 g of phthalic anhydride, 1.5 g of zinc acetate and 50 g of propylene glycol, In an inert gas atmosphere, while maintaining the temperature at 130 to 150 ° C, 500 g of propylene oxide was dropped from the dropping device over 90 minutes to cause a reaction, and after the completion of the dropping, the mixture was kept at 150 ° C for 1 hour to obtain an unsaturated polyester having an acid value of 3.8. Then, 60 parts of the polyester and 0.01 part of hydroquinone were mutually dissolved with 40 parts of styrene to obtain a resin (III).

Experiment 4 Into the same flask used in Experiment 1, isophthalic acid
830 g, adipic acid 730 g, dipropylene glycol 670 g,
And 530 g of diethylene glycol, and subjected to a condensation reaction at 230 ° C. in an inert gas atmosphere to obtain a saturated polyester having an acid value of 9.2.
The resin (4) was mutually dissolved with 60 parts of styrene together with 005 parts.

Experiment 5 40 parts of polystyrene having a molecular weight of about 10,000 were hydroquinone
The resin (5) was dissolved in 60 parts of styrene together with 0.01 part.

Experiment 6 A three-necked flask equipped with a reflux condenser, a stirrer, and a dropping device was charged with 1,000 g of water and 2.0 g of polyvinyl alcohol.
g, 135 g of methyl acrylate and 6 g of benzoyl peroxide using a dropper to add
After dropping, the mixture was kept at 85 ° C. for 4 hours. After cooling, the solid content was filtered off, washed with water and dried to obtain a styrene-methyl acrylate copolymer having a molecular weight of about 120,000. 40 parts of the copolymer was dissolved in 60 parts of styrene together with 0.01 part of hydroquinone, and the resin (6 ).

〔Example〕

 Next, examples of the present invention and comparative examples will be described.

A lining composition solution was prepared according to the formulation shown in Table 1.

After mixing the raw materials, 150φ x 500mm tube, rotation speed 100-5
After lining at 00 rpm and a tube temperature of 70 ° C., the tube was cured at a temperature of 80 ° C. for 1 hour. Various performance test results such as workability and storage stability during molding of the obtained lining tube
It is as shown in the table.

The silica sand used as the filler in Table 1 was fine sand / 5 // 7
No. is blended in 1/1/1.

[Effect] As described above, the present invention uses a resin composition that exhibits no shrinkage or expansion during curing, and even if the inner wall surface of the tube has some irregularities, the primer is uniformly pressed without unevenness. There is no need to apply any treatment and the economic effect is great.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Hiroshi Okamoto, Inventor 5-8-8 Nishiburi-cho, Suita-shi, Osaka Japan Resin Research Laboratory, Nihon Shokubai Chemical Industry Co., Ltd. No. 8 in Resin Laboratory, Nihon Catalytic Chemical Industry Co., Ltd. (56) References JP-A-60-244378 (JP, A)

Claims (2)

(57) [Claims] 1. A thermoplastic resin (B) having compatibility with 100 parts by weight of an unsaturated polyester resin (A) and a crosslinkable vinyl monomer contained in the unsaturated polyester resin (A).
1 to 100 parts by weight and an inorganic or organic filler (C) 100
硬化 1800 parts by weight of a curing agent, and a resin composition exhibiting no shrinkage or expansion during curing is supplied to the inner surface of the rotating tube, and a layer of the composition is centrifugally formed on the inner peripheral surface of the tube. An anticorrosion lining method for the inner surface of a pipe, characterized in that the pipe is cured. 2. 100 parts by weight of an unsaturated polyester resin (A) containing a curing agent, and said unsaturated polyester resin (A)
1-100 parts by weight of a thermoplastic resin (B) compatible with the crosslinkable vinyl monomer contained therein is supplied to the inner surface of the rotating tube to form a uniform resin layer on the inner peripheral surface, and further filled. 100-1800 parts by weight of the material (C) are evenly dispersed, the filler is submerged in the resin liquid layer by centrifugal force, and the resin composition layer which is formed and shows no shrinkage or expansion at the time of curing is cured. The anticorrosion lining method for the inner surface of the pipe.