JPH0473128A - Preparation of polyphenylene sulfide resin lining metal pipe - Google Patents

Abstract

PURPOSE:To prepare a metal pipe excellent in heat resistance, corrosion resistance, acid resistance, alkali resistance and chemical resistance by lining the metal pipe with a polyphenylene sulfide resin (PPS) molded at specific m.p. temp. CONSTITUTION:When melting temp. is set to 330 - 420 deg.C, especially pref., to 340 - 400 deg.C at the time of the manufacturing of a PPS pipe, the PPS pipe low in a degree of crystallization and rich in flexibility can be stably obtained even when no special cooling treatment is performed. When the PPS pipe is formed into a thermally expansible pipe having an outer diameter smaller than the inner diameter of a metal pipe by contraction or stretching, for example, a die having an inner diameter smaller than the outer diameter of the pipe is used and the temp. contracting or stretching the PPS pipe is set to 70 - 140 deg.C, especially pref., to 75 - 130 deg.C. When the PPS pipe thus obtained is inserted in the metal pipe, for example, an adhesive is applied to the inner surface of the metal pipe and the outer surface of the PPS pipe and the PPS pipe is inserted in the metal pipe and heated to the softening point thereof or higher to be expanded to be closely bonded to the inner wall of the metal pipe.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a metal tube lined with polyphenylene sulfide resin (hereinafter abbreviated as PPS), which has excellent heat resistance, corrosion resistance, acid resistance, alkali resistance, chemical resistance, etc. The production method according to the present invention stably produces PPS.
It is possible to obtain lined metal tubes. In addition, the PPS-lined metal pipes obtained by the method of the present invention are used as hot water pipes and hot spring pipes in various buildings, hot water/chemical/solvent pipes in power plants, chemical plants, etc., and oil country tubular goods.

<Prior Art> Plastic-lined metal pipes are made of iron, stainless steel, or other metal pipes that have poor corrosion resistance, and the inner or outer surfaces of the pipes are protected with plastic that has excellent corrosion resistance, and are used for various types of piping. In particular, PPS-lined metal pipes are lined with PPS, a highly functional engineering plastic with excellent corrosion resistance, chemical resistance, heat resistance, and flame retardancy. 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 lined metal pipes using PPS has already been published in Japanese Patent Application Laid-open Nos. 59-85747 and 61.
A proposal has been made in the publication No.-162323. but,
In the case of JP-A-59-85747, a non-expandable PPS tube is inserted into a heated metal tube at room temperature, and the metal tube is squeezed with great force to bond it to the PPS tube. The problem was that a large amount of force was applied and there were many problems such as breakage. Also, JP-A-61-16
Publication No. 2323 uses a PPS tube subjected to solid phase extrusion, but in the case of PPS, it is necessary to use a special extruder with high pressure output in order to form a tube of uniform thickness by solid phase extrusion. However, it was extremely difficult to apply this manufacturing method industrially.

As a method for improving the above problems, JP-A No. 63-2818
No. 28 proposes a method using a heat-expandable PPS tube. However, although PPS has high rigidity, it is very brittle and has poor flexibility, so it is difficult to obtain a tube with excellent flexibility that can be used as a thermally expandable tube using normal molding methods. Ta. Therefore, PPS
Attempts have been made to add other highly flexible polymers to give PPS flexibility, or to suppress the crystallinity of PPS by rapidly cooling it. Nevertheless, the blending method
To date, no polymer that is compatible with S has been found, and even when a polymer with a certain degree of affinity is added, it is necessary to add a large amount in order to provide sufficient flexibility. Therefore, there was a problem in that properties characteristic of PPS, such as heat resistance, chemical resistance, and flame retardancy, were lost. On the other hand, in the case of rapid cooling, subtle fluctuations in the cooling conditions have a very large effect on the flexibility of the tube.
There were problems such as large opening and tremors, and the inability to perform continuous tube contraction operations after tube forming. In addition, when creating thermally expandable tubes by shrinking or stretching tubes, they may break due to lack of flexibility at low temperatures, or they may be affected by crystallization even at high temperatures where they are considered to be highly flexible. There were problems such as plastic deformation of the molecules, which resulted in a decrease in thermal expansion and flexibility.

<Problems to be Solved by the Invention> In view of the above-mentioned circumstances, the present invention provides a method for manufacturing a lined metal tube in which the metal tube is lined with a PPS tube having excellent thermal expansion properties. It is in.

<Means for solving the problems> The present invention provides PPS molded at 330 to 420'C.
The present invention relates to a method for manufacturing a PPS-lined metal tube characterized by lining the tube.

The method for manufacturing a PPS pipe for lining in the present invention is a method for manufacturing a normal PPS pipe, but the melting temperature is set to 330-330°C.
It is necessary to set the temperature to 420°C, particularly preferably 340 to 400°C. At a molding temperature lower than the conventional 330°C, rapid cooling is required after tube forming to obtain a PPS tube with low crystallinity, and continuous tube shrinking operation cannot be performed after tube forming. This is undesirable because problems such as variation in the flexibility of the tube due to slight fluctuations in cooling conditions occur. As the melting temperature of PPS increases, the apparent crystallization rate decreases;
When molded at a high temperature of 0° C. or higher, a highly flexible tube with low crystallinity can be stably obtained without any special cooling treatment.

Further, if the temperature exceeds 420°C, the decomposition of the resin will become significant, which is not preferable. The crystallization rate seems to be correlated with the size of the molecular weight, and generally, within the above molding temperature range, those with a low molecular weight need to be molded at a higher temperature.

The melting temperature corresponds to, for example, the barrel temperature when an extruder is used, and the discharge temperature of the resin does not necessarily need to be within the above temperature range as long as it is within the normal PPS temperature range.

However, it is necessary to discharge within 5 minutes from the position of the barrel set at the above temperature.

In addition, PPS pipes usually have an outer diameter that is the same as or larger than the inner diameter of the metal pipe, and a wall thickness of 0.5 mm. A range of 1 to 5 mm is preferred.

The above-mentioned PPS tube can be made into a thermally expandable tube with an outer diameter smaller than the inner diameter of the metal tube by shrinking or stretching, using known methods such as using a die with an inner diameter smaller than the outer diameter of the tube. However, the temperature at which the tube is contracted or stretched is 70 to 140"C2, particularly preferably 75 to 130"C2.
It needs to be ℃.

In this case, at temperatures above 140° C., crystallization of PPS progresses and the relaxation time of molecular motion in the amorphous phase becomes extremely rapid, making it easy for plastic deformation to occur, which is undesirable because thermal expansion property decreases. Further, if the temperature is below 70°C, the tube is likely to break, 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 moiety in the structural unit represented by (-A-8-) is p-phenylene. Structural components other than the p-phenylene moiety include m-phenylene, O-phenylene, 2゜6-naphthalene, 4.4-
There is a divalent aromatic residue containing biphenylene, or two aromatic rings having 6 carbon atoms, and each aromatic ring contains F, CQ, Br, (
: A substituent such as H3 may be introduced. This may be a homopolymer, a random copolymer, or a block copolymer. Preferable examples include a block copolymer consisting of a PPS portion and a polyphenylene sulfide ketone portion, and a flock copolymer consisting of a PPS portion and a polyphenylene sulfide sulfone portion. In the case of a homopolymer, the real part (η') of the complex viscosity at 300°C and 100 rad/see measured with a parallel plate viscometer is 10 to 106 poise, more preferably 500 to 5000 poise. The shape of the molecular chain of PPS in which 70 mol% or more, particularly preferably 90 mol% or more of the -Ar portion in the general structural formula of the sulfide bond-containing sulfur arylene resin is used, has a melt viscosity within this range. , linear, branched, partially crosslinked, and mixtures thereof.

In addition to the above, PPS is formed by a synthesis process or a post-treatment process.The method for polymerizing the above-mentioned PPS is generally known, for example, by adding p-dichlorobenzene in the presence of sulfur and sodium carbonate. A method of polymerization, a method of polymerization in the presence of sodium sulfide, sodium bisulfide and sodium hydroxide, or hydrogen sulfide and sodium hydroxide in a polar solvent;
There is a method of self-condensation of p-chlorothiophenol, but there is also a method of reacting sodium sulfide and p-dichlorobenzene in an amide solvent such as N-methylpyrrolidone, dimethylacedoide, or mido, or a sulfonic solvent such as sulfolane. Most common.

Such PPS has a dynamic viscosity [η°] of 500 to 10' poise, preferably 1000 to 50000 poise at 300°C and 10 rad/sec, and is linear or partially crosslinked. It is preferable that the degree of curvature is low and that the shape is close to linear.

Furthermore, PPS can be mixed with the following polymers in proportions that do not impair the properties required for the purpose. These polymers include ethylene, phthylene, pentene, phtadiene, iso-7-lene, chlorobrene, styrene, α-
Homopolymers or copolymers of monomers such as methylstyrene, vinyl acetate, vinyl chloride, acrylic esters, methacrylic esters, (meth)acrylonitrile,
Ionomer polyester, polycarbonate, polysulfone, polyaryl sulfone, polyether sulfone, polyarylate, polyphenylene oxide, polyphenylene sulfide ketone, polyether ether ketone, polyimide, polyamide, polyetherimide, 7 silicone resin, fluororesin, Examples include homopolymers, random copolymers, block copolymers, and graft copolymers such as polyaryl ether.

In addition, PPS includes fibrous reinforcement materials such as glass fiber, carbon fiber, potassium titanate, whisker asbestos, silicon carbide, boron fiber, and aramid fiber; barium sulfate,
Cal/rum sulfate, kaolin, clay pyrophyllite, bentonite, zeolite, mica, mica, talc,
Ferrite, Cal/Rum silicate, Cal/Rum carbonate, magnesium carbonate, dolomite, antimony dioxide, zinc oxide, titanium oxide, magnesium oxide, iron oxide, molybdenum disulfide, graphite, gypsum, glass peas, glass balloon, quartz powder It is possible to contain up to 80% by weight of inorganic fillers such as. When adding these reinforcing agents or fillers, known silane or titanium coupling agents can be used in combination.

Further, small amounts of a mold release agent, a coloring agent, a heat stabilizer, an ultraviolet stabilizer, a foaming agent, a flame retardant, a flame retardant aid, and a rust preventive agent can also be contained.

The metal tube used in the present invention can be a generally known metal or alloy tube.

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 PP
There is a method in which an adhesive is applied to the outer surface of the S-tube, the PPS tube is inserted into the metal tube, and the PPS tube is expanded under heating above the softening point temperature to tightly adhere to the inner wall of the metal tube.

Further, as the adhesive used in the present invention, various commonly known adhesives can be used, but it is preferable to use one that is stable against heat of 300°C or higher, such as polyphenylene oxide, polyamide, Examples include polysulfone, styrene-butadiene copolymer, polyurethane, Epoquin resin, phenol resin, unsaturated polyester, polyamideimide, and vinyl ester resin.

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

Example 1 A tube with an outer diameter of about 60 mm and a wall thickness of about 2 mm was produced at a speed of 0.5 m/min using a 90 mm extruder with PPS set at 350°C. The obtained tube was transparent and of poor quality. When this tube was subjected to X-ray diffraction, only a very broad peak, which was thought to be due to the orientation of the molecules, was observed, and no distinct diffraction image due to crystals was obtained.

This tube was passed through a constant temperature bath at 100°C, and the outer diameter was 57 mm.
The tube was shrunk through a sizing device to obtain a PPS thermally expandable tube. The rate of constriction is 0.0 per minute. It was 5m and smooth. The obtained thermal expansion tube was inserted into a steel tube with an inner diameter of 60 mm, heated to 250 ''C, and then allowed to cool to produce a lining tube. The adhesion between the steel tube and the PPS tube was good.

The PPS used was 300°C and 10 rad/see.
The dynamic viscosity [η゛] was approximately 4000 poise.

Comparative Example 1 A PPS tube was produced in the same manner as in Example 1, with the extruder set at 300'C. In the X-ray diffraction image of the obtained tube, a Noyab diffraction peak was clearly observed around 22 degrees, which is thought to be that of PPS crystals. The degree of crystallinity estimated from X-ray diffraction was about 35%. In order to stably shrink this tube, the set temperature of the constant temperature bath had to be 150° C. or higher. When the tube was contracted at 150° C. and lined using the same method as in Example 1, the thermal expansion property was insufficient and the PPS tube did not adhere to the steel tube.

The PPS used was the same as in Example 1.

Example 2 A PPS pipe was molded at a speed of 0.5 m per minute using an extruder set at 360″C, and a sizing device was placed in front of the extruder to perform sizing treatment continuously. The process was stable. The outer diameter of the obtained thermal expansion tube was approximately 57 mm, and the wall thickness was approximately 2 mm.Also, no crystallinity was confirmed by X-ray diffraction.Epoxy resin was applied to the surface of this tube. A lined pipe was obtained in the same manner as in Example 1.The adhesion between the PPS pipe and the steel pipe was good.The dynamic viscosity of the PF'S used at 300°C and 110 rad/see was approximately 10
It is of 000 poise.

Comparative Example 2 An attempt was made to create a thermal expansion tube using the same method as in Example 2 using an extruder set at 300°C. The sizing process could not be carried out stably unless the sizing device was closely attached to the extruder.

The outer diameter of the obtained thermally expandable tube was approximately 58 mm, and the wall thickness was approximately 2.5 mm.
It was 2 mm. In addition, the crystallinity obtained by X-ray diffraction is approximately 4
It was 0%. An attempt was made to line a steel pipe using the same method as in Example 2, but the PPS pipe had almost no thermal expansion, and it was not possible to create a lined pipe. In addition, for the purpose of rapid cooling after extruding the tube, 5 to 20 cm of the nozzle of the extruder is
Cooling air at about 20° C. was applied in front of the tube, but the wall thickness of the tube became quite uneven and the tube was damaged, making stable sizing impossible. Note that the PPS used was the same as in Example 2.

<Effects of the Invention> In the method for manufacturing a PPS lined metal pipe according to the present invention, PPS
When shrinking the PS tube, there is very little damage to the reading tube.
A highly stable thermally expandable PPS tube is lined on the inner surface of the metal tube.

Claims (1)

[Claims] 1. A method for manufacturing a polyphenylene sulfide resin-lined metal tube, characterized in that the tube is lined with a polyphenylene sulfide resin tube molded at a melting temperature of 330 to 420°C. 2. Polyphenylene sulfide resin pipe is 70-140℃
2. The method for manufacturing a polyphenylene sulfide resin-lined metal tube according to claim 1, wherein the diameter is reduced or stretched in a temperature range of .