JP2964570B2 - Method for producing polyphenylene sulfide resin-lined metal tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention relates to a metal pipe lined with a polyphenylene sulfide resin (hereinafter abbreviated as PPS) having excellent heat resistance, corrosion resistance, acid resistance, alkali resistance, chemical resistance and the like. The production method according to the present invention makes it possible to stably obtain a PPS-lined metal tube. The PPS-lined metal pipe obtained by the method according to the present invention is used as a hot water pipe or a hot spring pipe of various buildings, a hot water / chemical / solvent pipe or an oil well pipe in a power plant or a chemical plant.

<Prior Art> A lining metal pipe made of plastic protects an inner surface or an outer surface of a metal pipe such as iron or stainless steel having poor corrosion resistance with a plastic having excellent corrosion resistance, and is used for various pipes. Above all, lining metal pipes using PPS are lining PPS, which is a high-performance engineering plastic with excellent corrosion resistance, chemical resistance, heat resistance, flame retardancy, etc. It is also expected to be used as special piping for chemical plants that require hot water resistance, corrosion resistance, and chemical resistance. A method for manufacturing a lining metal pipe using PPS has already been disclosed in Japanese Patent Application Laid-Open Nos. 59-85747 and 61-162323.
A proposal is made in Japanese Patent Publication No. However, Japanese Patent Application Laid-Open No. 59-8574
In the case of No. 7, in order to insert a non-expandable PPS tube at room temperature into a heated metal tube and squeeze the metal tube with a large force to adhere to the PPS tube, an extremely large force is applied to the PPS tube. The problem was that there were many troubles such as breakage.
Japanese Patent Application Laid-Open No. 61-162323 uses a solid-phase extruded PPS tube. In the case of PPS, a special extruder with a high-pressure output is used to form a tube of uniform thickness by solid-phase extrusion. Therefore, it was extremely difficult to apply this production method industrially.

As a method for solving the above problem, Japanese Patent Application Laid-Open No. 63-281828 proposes a method using a heat-expandable PPS tube. However, while PPS has high rigidity, it is very brittle and poor in flexibility, so it is difficult to obtain a tube having excellent flexibility that can be used as a thermally expandable tube by a normal molding method. Was. For this reason, there have been attempts to add a polymer having excellent flexibility in order to impart flexibility to the PPS, or to suppress the crystallinity of the PPS by rapidly cooling the polymer. Nevertheless, a polymer compatible with PPS has not yet been found by the blending method at present, and even if a polymer with a certain degree of affinity is added, it is necessary to provide sufficient flexibility. It is necessary to add a large amount, so that heat resistance, chemical resistance, flame resistance, etc.
There was a problem that the characteristic property of PPS was lost. On the other hand, in the case of rapid cooling, since subtle fluctuations in cooling conditions have a very large effect on the flexibility of the pipe, problems such as large lot runout and the inability to continuously perform the contraction operation after the pipe is formed. there were. Also, when creating a thermally expandable tube by contracting or stretching the tube, it may break due to lack of flexibility at low temperatures, and the effects of crystallization in a high temperature region where flexibility is considered to be high. On the contrary, there is a problem that the thermal expansion property and the flexibility are lowered in terms of plastic deformation of the molecule.

<Problems to be Solved by the Invention> In view of the above circumstances, the present invention provides a method for manufacturing a lining metal pipe in which a PPS pipe excellent in heat expansion property is lined with a metal pipe when lining the metal pipe. It is in.

<Means for Solving the Problems> The present invention relates to a method for producing a PPS-lined metal tube, which is characterized by lining with a PPS tube formed at 330 to 420 ° C.

The method for producing a lining PPS pipe in the present invention is the same as the ordinary PPS pipe production method, except that the melting temperature is 330 to 420.
° C, particularly preferably 340-400 ° C. At a molding temperature lower than the conventional 330 ° C, it is necessary to cool rapidly after forming the tube in order to obtain a PPS tube with low crystallinity. It is not preferable because problems such as variations in the flexibility of the pipe obtained due to subtle variations in cooling conditions occur. Since the apparent crystallization rate decreases as the melting temperature increases, PPS has a low degree of crystallinity and flexibility without special cooling when molded at temperatures higher than 330 ° C. It becomes possible to obtain a tube stably. Also,
If the temperature exceeds 420 ° C., the decomposition of the resin becomes remarkable, which is not preferable. The crystallization rate is considered to be correlated with the magnitude of the molecular weight. Generally, within the above-mentioned molding temperature range, a low-molecular-weight one needs to be molded at a higher temperature. The melting temperature is, for example, equivalent to the barrel temperature when using an extruder, and the resin discharge temperature is within the normal PPS temperature range,
It does not necessarily need to be within the above temperature range. However, it is necessary to discharge within 5 minutes from the position of the barrel set at the above temperature.

In addition, the PPS pipe usually has an outer diameter equal to or larger than the inner diameter of the metal pipe, and the wall thickness is preferably in the range of 0.1 to 5 mm.

Known methods, such as a method using a die having an inner diameter smaller than the outer diameter of the pipe, can be used as a method for forming the PPS pipe into a thermally expandable pipe having an outer diameter smaller than the inner diameter of the metal pipe by contracting or stretching. However, the temperature at which the tube is drawn or stretched must be 70 to 140 ° C, particularly preferably 75 to 130 ° C. In this case, if the temperature is 140 ° C. or higher, the crystallization of PPS proceeds, and the relaxation time of the molecular motion of the amorphous phase becomes extremely fast, so that plastic deformation is likely to occur, and therefore, the heat expansion property is undesirably reduced. On the other hand, if the temperature is lower than 70 ° C., the tube is easily broken, which is not preferable.

In the PPS used in the present invention, 70 mol% or more, particularly preferably 90 mol% or more, of the A portion in the structural unit represented by (-AS-) is p-phenylene. p-
The structural components other than the phenylene moiety include m-phenylene,
o-phenylene, 2,6-naphthalene, 4,4-biphenylene and the like, or And the like, and a divalent aromatic residue containing at least two aromatic rings having 6 carbon atoms, and further, F, Cl, Br, CH ₃
And the like may be introduced. This may be a homopolymer, a random copolymer, or a block copolymer. Preferably, a block copolymer composed of a PPS part and a polyphenylene sulfide ketone part, a block copolymer composed of a PPS part and a polyphenylene sulfide sulfone part, and the like are used. In the case of a homopolymer, measurement was performed with a parallel plate type viscometer, 30
The real part (η ′) of the complex viscosity at 0 ° C. and 100 rad / sec is 10 to 1
70 mol% of the -Ar- moiety in the general structural formula of the sulfur arylene resin having a melt viscosity in the range of ⁵ poises, more preferably in the range of 500 to 5000 poises, and having a sulfide bond.
Or more, particularly preferably 90 mol% or more It is a PPS composed of bonds. The molecular chains of the PPS used may be linear, branched, partially crosslinked, or a mixture thereof. Also configure PPS Other components include, for example, formed by a synthesis process and a post-treatment process in addition to the above. Also included.

As a method of the polymerization of the PPS, generally known methods, for example, a method of polymerizing p-dichlorobenzene in the presence of sulfur and sodium carbonate, sodium sulfide or sodium hydrosulfide and sodium hydroxide in a polar solvent Alternatively, there is a method of polymerizing in the presence of hydrogen sulfide and sodium hydroxide, a method of self-condensation of p-chlorothiophenol, but in an amide solvent such as N-methylpyrrolidone, dimethylacetamide or a sulfone solvent such as sulfolane. The most common method is to react sodium sulfide with p-dichlorobenzene.

Such PPS is, 300 ° C., a dynamic viscosity at 10rad / sec [η '] is 500 to ⁵ poise, preferably in a range of 1,000 to 50,000 poise, the cross-linked with that of the linear or partially crosslinked type Those having a low degree and close to a linear shape are preferred.

Further, the following polymers can be mixed and used in the PPS at a ratio that does not impair the properties required for the application. These polymers include ethylene, butylene, pentene, butadiene, isoprene, chloroprene, styrene, α-
Homopolymers or copolymers of monomers such as methylstyrene, vinyl acetate, vinyl chloride, acrylates, methacrylates, (meth) acrylonitrile, ionomers, polyesters, polycarbonates, polysulfones, polyarylsulfones, polyethers Sulfone, polyarylate, polyphenylene oxide, polyphenylene sulfide ketone, polyetheretherketone, polyimide, polyamideimide, polyetherimide, silicone resin, fluororesin, polyarylether, homopolymer, random copolymer, etc. Examples include block copolymers and graft copolymers.

In addition, PPS includes fibrous reinforcing agents such as glass fiber, carbon fiber, potassium titanate, whisker, asbestos, silicon carbide, boron fiber, and aramid fiber; barium sulfate,
Calcium sulfate, kaolin, clay, virophilite, bentonite, zeolite, mica, mica, talc, ferrite, calcium silicate, calcium carbonate, magnesium carbonate, dolomite, antimony trioxide, zinc oxide, titanium oxide, magnesium oxide, iron oxide Inorganic fillers such as molybdenum disulfide, graphite, stone, glass beads, glass balloons, and quartz powder can be contained up to 80% by weight. When adding these reinforcing agents or fillers, known silane or titanium coupling agents can be used in combination.

In addition, a small amount of a release agent, a colorant, a heat stabilizer, an ultraviolet stabilizer, a foaming agent, a flame retardant, a flame retardant auxiliary, and a rust inhibitor can be added.

As the metal tube used in the present invention, a generally known metal or alloy tube can be used. For example,
Examples include iron, stainless steel, brass, copper, aluminum, titanium, duralumin, zinc, tin, and nickel.

A known method can be used to insert the PPS tube into the metal tube. For example, the inner surface of a metal tube and / or PPS
There is a method in which an adhesive is applied to the outer surface of the tube, the PPS tube is inserted into the metal tube, and the PPS tube is expanded under heating at a temperature equal to or higher than the softening point to adhere to the inner wall of the metal tube.

In addition, the adhesive used in the present invention can use various adhesives generally known, but those that are stable to heat of 300 ° C. or more are preferable, for example, polyphenylene oxide, polyamide, Examples include polysulfone, styrene-butadiene copolymer, polyurethane, epoxy resin, phenol resin, unsaturated polyester, polyamide imide, vinyl ester resin, and the like.

<Examples> The present invention will be specifically described based on examples. But,
The present invention is not limited to the following examples.

Example 1 Using a 90 mm extruder with a PPS set at 350 ° C., an outer diameter of about 60 m
m, a tube having a wall thickness of about 2 mm was produced at a speed of 0.5 m / min. The resulting tube was amorphous with a transparent tube. The tube was subjected to X-ray diffraction, and only a very broad peak, probably due to molecular orientation, was observed, but no sharp diffraction image due to the crystal was obtained. This tube is 10
The tube was contracted through a thermostat at 0 ° C. and further through a sizing device having an outer diameter of 57 mm to obtain a PPS thermally expandable tube. The speed of the tube was 0.5 m / min, which was smooth. The obtained thermal expansion tube was inserted into a steel tube having an inner diameter of 60 mm, heated to 250 ° C., and allowed to cool to prepare a lining tube. The adhesion between the steel pipe and the PPS pipe was good.

The PPS used had a dynamic viscosity [η ′] at 300 ° C. and 10 rad / sec of about 4000 poise.

Comparative Example 1 A PPS tube was prepared in the same manner as in Example 1 except that the set temperature of the extruder was set to 300 ° C. In the X-ray diffraction image of the obtained tube, a sharp diffraction peak was clearly observed at around 22 degrees, which is considered to be a PPS crystal. The crystallinity estimated from X-ray diffraction was about 35%. In order to stably shrink this tube, the set temperature of the thermostat had to be 150 ° C. or higher. After contraction at 150 ° C. and lining in the same manner as in Example 1, the thermal expansion was insufficient and the PPS pipe did not adhere to the steel pipe.

 The PPS used was the same as in Example 1.

Example 2 Using an extruder set at 360 ° C., a PPS tube was formed at a speed of 0.5 m / min, a sizing device was placed in front of the extruder, and sizing was continuously performed. The process was stable. The outer diameter of the obtained thermal expansion tube was about 57 mm, and the wall thickness was about 2 mm. No crystallinity could be confirmed by X-ray diffraction. An epoxy resin was applied to the surface of this tube, and a lining tube was obtained in the same manner as in Example 1. The adhesion between the PPS pipe and the steel pipe was good. The PPS used had a dynamic viscosity of about 10,000 poise at 300 ° C. and 10 rad / sec.

Comparative Example 2 An extruder set at 300 ° C. was used to create a thermal expansion tube in the same manner as in Example 2. If the sizing device was not attached to the extruder, the sizing process could not be performed stably. The outer diameter of the obtained thermally expandable tube was about 58 mm, and the wall thickness was about 2.2 mm. The crystallinity obtained by X-ray diffraction was about 40%. A lining was attempted on the steel pipe in the same manner as in Example 2, but the PPS pipe had almost no thermal expansion property, and the lining pipe could not be formed. In addition, for the purpose of quenching the extruder of the pipe, cooling air of about 20 ° C. was added 5 to 20 cm in front of the nozzle of the extruder, but considerable unevenness in the wall thickness of the pipe occurred, and the pipe was broken, Sizing could not be performed stably. In addition, used
The PPS is the same as in the second embodiment.

<Effect of the Invention> In the method for producing a PPS-lined metal tube according to the present invention, the PPS
When the tube is contracted, the PPS tube is lined on the inner surface of the metal tube with very little thermal destruction and extremely stable thermal expansion.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B29C 63/00-63/48 F16L 58/00-58/16

Claims (2)

(57) [Claims] 1. A method for producing a polyphenylene sulfide resin-lined metal pipe, which comprises lining with a polyphenylene sulfide resin pipe molded at a melting temperature of 330 to 420 ° C. 2. A polyphenylene sulfide resin tube having a diameter of 70 to 14
The method for producing a polyphenylene sulfide resin-lined metal pipe according to claim 1, wherein the diameter is reduced or stretched in a temperature range of 0 ° C.