JP2001058353A - Vinyl chloride resin pipe for heat-resistant thermally expansible lining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the contact of a metal pipe and a vinyl chloride resin pipe by forming the vinyl chloride resin pipe for heat-resistant thermally expansible lining provided to the inner wall of the metal pipe from a chlorinated vinyl chloride resin mixed with a specific amt. of a vinyl chloride resin. SOLUTION: In a vinyl chloride resin coated metal pipe wherein the inner wall of a metal pipe is lined with a vinyl chloride resin layer in order to impact corrosion resistance to the inner surface of the metal pipe, a vinyl chloride resin pipe for heat-resistant thermally expansible lining formed from a compsn. wherein 100 pts.wt. of a chlorinated vinyl chloride resin is mixed with 50-110 pts.wt. of a vinyl chloride resin is used. This vinyl chloride resin pipe is inserted in the metal pipe and expanded in its diameter by heating to be laminated to the inner surface of the metal pipe. The diameter expanding ratio of the vinyl chloride resin pipe allowed to stand in a heating medium such as air or the like at 150-180 deg.C for 2 min. is 105-130%. A layer comprising a hot-metal adhesive may be provided on the outer surface of the vinyl chloride resin pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant, thermally expandable vinyl chloride resin tube for lining.

[0002]

2. Description of the Related Art It is generally known that a vinyl chloride resin layer is lined on the inner wall of a metal tube in order to impart corrosion resistance to the inner surface of a metal tube such as a steel tube. The vinyl chloride resin-coated metal tube is manufactured by bonding the vinyl chloride resin tube to the inner surface of the metal tube via an adhesive by heating and expanding. At this time, since the difference in linear expansion coefficient between the vinyl chloride resin pipe for lining and the metal pipe is large, stress in the peeling direction is applied to the adhesive layer in the cooling process in the production of the vinyl chloride resin-coated metal pipe, and the vinyl chloride is applied. The phenomenon of so-called "floating" in which the resin pipe and the metal pipe are separated easily occurs. In particular, this phenomenon appears remarkably in a heat-resistant vinyl chloride resin tube having a softening temperature, that is, a shrinkage initiation temperature higher than that of a general vinyl chloride tube. In order to prevent this, a method has been used in which a pressurized medium is sealed inside a heat-resistant vinyl chloride tube to cool while suppressing shrinkage during the cooling process.

[0003]

However, in order to use the above-described method for sealing a pressurized medium, an apparatus for sealing a pressurized medium is required. In addition, encapsulation of the pressurized medium,
Cooling, removal of the pressurized medium, and the number of work steps increase, and the work is also troublesome.

[0004] Therefore, an object of the present invention is to solve the above-mentioned problems and improve the adhesion between a metal pipe and a vinyl chloride pipe.

[0005]

The invention relating to the heat-resistant, thermally expandable vinyl chloride resin pipe for lining is characterized in that the vinyl chloride resin is used in an amount of 50 to 50 parts by weight per 100 parts by weight of the chlorinated vinyl chloride resin.
The above problem was solved by using a heat-resistant, thermally expandable vinyl chloride resin tube for lining mixed with 110 parts by weight.

Furthermore, as the above-mentioned heat-resistant, thermally expandable vinyl chloride resin pipe for lining, a pipe having an expansion ratio of 105% to 130% when heated at a temperature of 150 ° C. to 180 ° C. for 2 minutes can be used. .

[0007] The invention relating to a heat-resistant, heat-expandable lining vinyl chloride resin tube having an adhesive layer laminated thereon, mainly comprises a crystalline polyester on the outer surface of the heat-resistant, heat-expandable lining vinyl chloride resin tube. Component and its melting point is 12
A hot-melt adhesive layer of 0 ° C. to 150 ° C. is provided, and the Vicat softening temperature (1 kg load) of the mixed resin constituting the heat-resistant, thermally expandable vinyl chloride resin tube for lining is determined by the crystal of the hot-melt adhesive. Below 110 ° C. and above 110 ° C.

[0008] The phenomenon of "floating" in the cooling process in the production of a vinyl chloride-coated metal tube is that the softened vinyl chloride tube is heated to a softening temperature before the hot-melt adhesive melted is cooled to the crystallization temperature and solidified. That is, when cooled to the shrinkage starting temperature, it is considered that the adhesive is generated because the vinyl chloride tube cannot be adhered to the inner surface of the metal tube. On the other hand, by using a heat-resistant, heat-expandable lining vinyl chloride resin tube or a hot-melt-type adhesive having the above-mentioned requirements, the heat-resistant, heat-expandable lining vinyl chloride resin tube is shrunk before the hot-melt-type Solidifies,
It is possible to prevent the vinyl chloride resin for the heat-resistant thermal expansion type lining from being peeled off from the heat-resistant vinyl chloride-coated metal tube. For this reason, a heat-resistant vinyl chloride resin-coated metal tube can be manufactured without causing "lifting" without enclosing a pressurized medium at the time of manufacture.

[0009]

Embodiments of the present invention will be described below.

The heat-resistant, thermally expandable vinyl chloride resin pipe for lining (hereinafter, abbreviated as "vinyl chloride pipe for lining") according to the present invention is formed by mixing a chlorinated vinyl chloride resin and a vinyl chloride resin. Pipe. This vinyl chloride pipe for lining is inserted into a metal pipe, and then heated and expanded to form a heat-resistant vinyl chloride-coated metal pipe (hereinafter, referred to as “coated metal pipe”) in which the vinyl chloride pipe for lining is attached to the inner surface of the metal pipe. Is abbreviated as ").

The chlorinated vinyl chloride resin refers to a vinyl chloride resin having a chlorination ratio of 60 to 72%, and the vinyl chloride resin refers to a vinyl chloride polymer having a chlorination ratio of 52% to 58%.

The mixing ratio of the chlorinated vinyl chloride resin and the vinyl chloride resin is preferably 50 to 110 parts by weight of the vinyl chloride resin per 100 parts by weight of the chlorinated vinyl chloride resin. If the mixing amount of the vinyl chloride resin is less than 50 parts by weight, a floating phenomenon occurs in which the vinyl chloride resin tube and the metal tube are separated without a pressurized medium when the lining is performed, and the adhesive strength between the two is low. A satisfactory product as a metal tube cannot be obtained. On the other hand, when the mixing amount of the vinyl chloride resin is more than 110 parts by weight, the Vicat softening temperature of the vinyl chloride resin tube is lowered, and the heat resistance is insufficient and the product is not practical.

The diameter expansion ratio of the above-mentioned vinyl chloride pipe for lining, when heated at a temperature of 150 ° C. to 180 ° C. for 2 minutes, is preferably 105 to 130%. 105
%, The outer surface of the vinyl chloride resin tube does not reach the inner surface of the metal tube at the time of manufacturing the lining metal tube, and even if it does, the adhesion to the inner surface of the metal tube is insufficient, so that the lining metal tube is satisfactory. I can't get the product. 130
If the temperature is higher than ℃, the outer surface of the vinyl chloride resin tube will expand more than necessary even after it adheres to the inner surface of the metal tube during production of the lining metal tube, so it will easily buckle in the metal tube, and both will adhere uniformly Can not be obtained.

Heating at a temperature of 150 ° C. to 180 ° for 2 minutes means that the lining vinyl chloride tube is left in a heating medium at a temperature of 150 ° C. to 180 ° C. for 2 minutes. Further, the expansion ratio is a ratio of the outer diameter of the expanded pipe after heating expansion to the outer diameter of the pipe before heating expansion when the vinyl chloride pipe for lining is heated and expanded by the above method. Say.

[0015] The above-mentioned vinyl chloride pipe for lining is provided on its outer surface with a layer made of a photomelt-type adhesive for joining the vinyl pipe for lining and the metal pipe. Vinyl tubes can be manufactured.

At this time, the Vicat softening temperature of the mixed resin constituting the lining vinyl chloride tube used for the lining vinyl chloride tube having the adhesive layer laminated thereon at a load of 1 kg is determined by the crystal of the hot melt type adhesive described later. It is preferable that the temperature is not higher than the activation temperature and not lower than 110 ° C. If the Vicat softening temperature is higher than the crystallization temperature of the hot-melt adhesive, shrinkage due to cooling of the lining vinyl chloride tube starts before the hot-melt adhesive solidifies, and the lining vinyl chloride tube peels from the metal tube. This is because "floating" is likely to occur. Also, the Vicat softening temperature is 1
If the temperature is lower than 10 ° C., when the above coated metal pipe is used as a pipe material for hot water supply, heat resistance may be insufficient, and when used at a high temperature, the metal pipe may be softened and lack practicality.

The Vicat softening temperature is defined by JIS K
In 7206 “Test method for Vicat softening temperature of thermoplastics” (test load: 1 kg), when the heat transfer medium was heated from room temperature at a rate of 50 ° C./hour, the indenter penetrated the test piece by a depth of 1 mm. The temperature at the time.

The above-mentioned hot-melt type adhesive can be generally bonded without using a solvent, and is therefore preferable from the viewpoint of environmental hygiene, and has the advantages that the drying step can be omitted, the application is easy, and the like. The hot-melt adhesive in this case is mainly composed of crystalline polyester and has a melting point of 120 ° C to 15 ° C.
0 ° C., crystallization temperature of 80 ° C. or higher and melting point or lower.
When the melting point of the hot melt type adhesive is lower than 120 ° C., heat resistance is poor, and peeling is likely to occur when used at a high temperature, which is not practical. Further, when the melting point exceeds 150 ° C., it is necessary to set the resin temperature excessively high when applying the adhesive to the heat-resistant thermally expanded vinyl chloride pipe, and this resin pipe may be thermally deformed,
Deterioration occurs due to thermal decomposition of the adhesive, which is inconvenient.

The above-mentioned crystalline polyester resin means a thermoplastic saturated copolymerized polyester obtained by the polycondensation of glycol and dicarboxylic acid. Examples of the acid component include terephthalic acid, isophthalic acid, orthophthalic acid, and phthalic acid. Aromatic dibasic acids such as phenylenedicarboxylic acid and 2,6-naphthalenedicarboxylic acid, succinic acid, glucuric acid, adipic acid, suberic acid, β-methyladipic acid, pimelic acid, 1,6-hexanedicarboxylic acid, azelaine Examples include aliphatic dibasic acids such as acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, hexadecanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid. As the glycol component, ethylene glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentadiol, 3-methylpentadiol, 1,3-hexanediol, Glycols such as 1,6-hexanediol, hydrogenated bisphenol A, diethylene glycol, 1,4-cyclohexanedimethanol, triethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, polytetramethylene glycol or a residue-forming derivative thereof or It can be obtained by copolymerizing by a conventional method by appropriately selecting an α, ω-oxy acid such as caprolactone or a saturated bifunctional monomer comprising a residue-forming derivative thereof.

Further, for the purpose of improving physical properties such as crystallinity, tri- or more functional acid components such as trimellitic acid and pyromellitic acid and / or tri- or more functional polyol components such as trimethylolpropanepentaerythritol are thoroughly copolymerized. It may be done. Further, a blend of two or more polyesters may be blended so that the melting point and the crystallization temperature of the crystalline polyester resin fall within the above ranges, or a blend of the same resins having different degrees of polymerization may be used.

Further, the crystalline polyester resin includes:
Polyolefin resin can be added. This polyolefin resin is suitable for improving low-temperature characteristics and water resistance. The polyolefin resin is not particularly limited, but is preferably a low-density polyethylene or a polyethylene resin obtained by copolymerizing propylene, maleic anhydride, vinyl acetate, acrylic acid, acrylate, methacrylic acid, or the like.

Further, as a polymer other than the polyolefin resin, for example, a thermoplastic resin such as an amorphous polyester resin, a polystyrene resin, a polyurethane resin, etc. may be blended, or an epoxy resin, a phenol resin, or the like. And a thermosetting resin such as a melamine resin. Further, as other additives, talc, clay, fillers such as silica, and the like for the purpose of improving the cohesive force or a coupling agent such as a silane coupling agent for the purpose of improving the adhesion to the metal tube,
Other known weather stabilizers, anti-aging agents, processing stabilizers, and the like can be added in a range that does not impair the features of the present invention.

Examples of the metal pipe include a steel pipe, a cast iron pipe,
SUS pipes, aluminum pipes, copper pipes and the like can be mentioned.

The above melting point can be measured by a differential scanning calorimeter. Specifically, the temperature observed as an endothermic peak when the temperature is increased to 200 ° C. at a scanning rate of 10 ° C./min, cooled to 0 ° C. at the same rate, and then raised again at the same rate is defined as the melting point. Can be. Further, the above crystallization temperature is set at 200 ° C. to 0 ° C. by performing the same operation as the melting point.
It refers to the temperature observed as an exothermic peak when cooled down, and usually shows a value below the melting point.

Next, a method for manufacturing the above coated metal tube will be described.

First, a chlorinated vinyl chloride resin and a vinyl chloride resin are mixed in the above-mentioned predetermined ratio for a heat-resistant, heat-expandable lining vinyl chloride resin tube used in the present invention.
Here, a known heat-resistant improver, a stabilizer, a filler, a lubricant, and the like can be mixed with the polyvinyl chloride resin as needed. After extruding this composition, it is immediately quenched to reduce the diameter to produce a heat-resistant, thermally expandable vinyl chloride resin tube for lining.

Next, the hot melt type adhesive layer is provided on the outer surface of the lining vinyl chloride pipe. this is,
A method of melt-coating the above-mentioned hot melt type adhesive with a crosshead die, a melt winding method of extruding and winding a hot melt type adhesive in a belt shape, or a film winding of winding a film type hot melt type adhesive on a polyvinyl chloride tube. It can be performed by an attaching method or the like.

The lining vinyl chloride tube provided with the obtained hot-melt type adhesive layer is inserted into a metal tube. Next, the temperature is raised to a temperature equal to or higher than the melting point of the hommelt type adhesive. This method of increasing the temperature can be performed by sequentially heating from one end to the other end or from the center to both ends with a burner, hot air or the like from the outside of the metal tube.
The reason why such a heating method is employed is to efficiently discharge air existing in the gap between the lining polyvinyl chloride pipe and the metal pipe to the end.

At this time, the diameter of the lining polyvinyl chloride pipe is increased, and the metal pipe and the lining vinyl chloride pipe are bonded to each other by the hot melt type adhesive layer.

Next, it is left to cool as it is. At this time, the hot-melt adhesive layer is first solidified, and then the lining vinyl chloride tube is solidified (cured). Since the hot melt type adhesive layer is solidified first, even if the lining vinyl chloride tube is solidified (hardened), shrinkage is suppressed.
As a result, occurrence of “floating” can be suppressed.

The coated metal pipe according to the present invention can be used for a hot water supply piping material, a heating piping material and the like.

[0032]

Next, the present invention will be described in more detail with reference to embodiments.

Example 1 (Production of vinyl chloride pipe for lining) Chlorinated vinyl chloride resin (hereinafter abbreviated as "CPVC") (manufactured by Kaneka Chemical Co., Ltd .: H-829, polymerization degree 800, chlorine) Conversion rate 69%) 1
00 parts by weight and a vinyl chloride resin (hereinafter abbreviated as “PVC”) (manufactured by Mitsubishi Chemical Corporation: SG-1100, degree of polymerization: 10)
00, chlorination rate 53%) 79 parts by weight,
2.3 parts by weight of octyltin compound heat stabilizer (manufactured by Nitto Kasei) and polyethylene lubricant (manufactured by Allied Chemical Company)
4.2 parts by weight, 10 parts by weight of a methyl methacrylate-butadiene-styrene copolymer (manufactured by Kaneka Chemical Co., Ltd.), 10 parts by weight of chlorinated polyethylene (manufactured by Daiso), and 0 filler (manufactured by Maruo Calcium Co., Ltd.) Was added and mixed.

This compounded composition is extruded into a cylindrical shape from a die by an extrusion molding method, and is guided to a cooling molding die while being in a softened state, and is cooled and solidified in order to reduce the diameter. afterwards,
It was cut to the required length to produce a lining PVC pipe.

The temperature of the resin extruded from the die in the above manufacturing method was about 190 ° C., and the temperature of the resin when entering the molding die was about 120 ° C.

The obtained lining polyvinyl chloride pipe had an outer diameter of 50.5 mm, a thickness of 3.0 mm, and a length of 4 mm.
It was 150 mm. The diameter expansion rate at 160 ° C. for 2 minutes in an oil bath was 10.5%, and the Vicat softening temperature was 113 ° C. (1 kg load).

(Lamination of Hot Melt Type Adhesive) A hot melt type adhesive layer was formed on the outer surface of the vinyl chloride pipe for lining. The hot-melt adhesive used was a polyester-based adhesive (melting point: 145 ° C., crystallization temperature: 120 ° C.).
° C), which was melted, applied to the outer surface of a vinyl chloride pipe for lining, and laminated. At this time, the coating film thickness was 0.1 mm.

(Production of coated metal tube) A vinyl chloride tube for lining provided with the hot melt type adhesive was inserted into a metal tube and heated. The metal pipe used at this time was a carbon steel pipe for piping (nominal diameter 50 A, outer diameter 60.5 mm, inner diameter 5
(2.9 mm, length 4000 mm), and heating was performed by blowing hot air onto the outer surface of the metal tube.

As a heating method, the metal tube is sequentially heated from the center to both ends (maintained at a tube temperature of 170 ° C. for 5 minutes).
Then, a method of natural cooling was adopted. Table 1 shows the appearance and adhesive strength of the obtained coated metal tube.

Comparative Example 1 (Production of vinyl chloride resin tube for lining) A vinyl chloride resin for lining was produced in the same manner as in Example 1 except that the composition of the heat-resistant vinyl chloride tube was changed to CPVC: PVC = 100: 10. Made of tubes. The Vicat softening temperature at this time is 12
It was 1 ° C.

(Lamination of Hot Melt Type Adhesive and Production of Coated Metal Tube) A heat-resistant vinyl chloride-coated steel tube was produced in the same manner as in Example 1 except that the above-mentioned vinyl chloride resin tube for lining was used. Table 1 shows the appearance and adhesive strength of the obtained coated metal tube.

[0042]

[Table 1]

[0043] Results The results showed the appearance of Example 1 was very good, was observed phenomenon of Comparative Example 1 "float". Also, the adhesive strength of Comparative Example 1 was significantly lower than that of Example 1.

[0044]

The heat-resistant vinyl chloride resin-coated metal pipe manufactured by using the lining vinyl chloride pipe obtained according to the present invention can be easily manufactured.
Further, the adhesion between the coated metal pipe and the lining polyvinyl chloride pipe can be improved without generating defects such as “floating”.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B32B 27/30 101 B32B 27/30 101 27/36 27/36 C08J 5/00 CEV C08J 5/00 CEV C08L 27/06 C08L 27/06 27/24 27/24 F16L 9/14 F16L 9/14 11/06 11/06 // C08J 5/18 CEV C08J 5/18 CEV B29K 27:06 67:00 705: 00 B29L 23:00 F-term (Reference) 3H111 AA01 AA02 BA01 BA15 BA34 CA52 CB03 CB04 DA26 DB03 EA12 4F071 AA23 AA24 AF43Y AH19 BA01 BB06 BC05 4F100 AB01C AK15A AK41B AL05A BA01 BA02 BA03 BA07 BA10A BA10B01B00 JA10 JA03 J02 JA03 YY00B 4F211 AA15 AA24 AD03 AD12 AG03 AG08 AH43 SA13 SC03 SD04 SG01 SH06 SN02 SP20 SP25 4J002 BD04X BD18W

Claims (4)

[Claims] 1. A heat-resistant, thermally expandable vinyl chloride resin pipe for lining, comprising 50 to 110 parts by weight of vinyl chloride resin mixed with 100 parts by weight of chlorinated vinyl chloride resin. 2. The heat-resistant, thermally expandable vinyl chloride resin pipe for a lining according to claim 1, wherein the diameter expansion ratio when heated at a temperature of 150 ° C. to 180 ° C. for 2 minutes is 105 to 130%. 3. A heat-resistant, heat-expandable lining vinyl chloride resin tube according to claim 1, wherein the outer surface of the heat-expandable lining vinyl chloride resin tube comprises crystalline polyester as a main component, and has a melting point of 120 ° C. to 150 ° C.
The hot-melt adhesive layer is provided, and the Vicat softening temperature (1 kg load) of the mixed resin constituting the heat-resistant thermally expandable lining vinyl chloride resin pipe is as follows:
Below the crystallization temperature of the hot melt adhesive,
A heat-resistant, heat-expandable lining vinyl chloride resin tube having an adhesive layer laminated at a temperature of 110 ° C. or higher. 4. The heat-resistant thermally-expandable vinyl chloride resin pipe according to claim 1 or 2, or the heat-resistant thermally-expandable vinyl chloride resin pipe having an adhesive layer laminated thereon according to claim 3 inside a metal pipe. A heat-resistant vinyl chloride-coated metal tube that has been heated and expanded in size and attached to the inner surface of the metal tube.