JP2001004072A - Pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve chemical resistance and heat resistance by using a material including a styrene polymer or a polymer having a syndiotactic structure. SOLUTION: In a pipe, an inside surface is formed of a material containing a styrene polymer or a polymer having a syndiotactic structure. That is, this is a pipe that a pipe inside surface directly contacting with fluid flowing in the pipe is formed of a material containing a styrene polymer or a polymer having the syndiotactic structure. The styrene polymer having the syndiotactic structure is a styrene polymer having a stereochemical structure that a phenyl group being a side chain is alternately positioned in the opposite direction to a principal chain having a stereochemical structure formed of the syndiotactic structure, that is, a carbon-carbon bond, and the tacticity is quantitatively determined by a nuclear magnetic resonance method by isotopic carbon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe, and more particularly, to a pipe useful for a machine tool or an apparatus in a chemical factory or a food manufacturing factory.

[0002]

2. Description of the Related Art Machines and equipment in chemical factories, food manufacturing factories, hot spring facilities, and the like are required to have chemical resistance and heat resistance. In particular, pipes used in these machines and equipment are directly used for chemical products, Because it is exposed to chemicals and high heat, it is a material that requires stricter chemical resistance and heat resistance.

[0003] As such a pipe, a steel pipe is usually used, but it has a drawback that it is excellent in heat resistance but inferior in chemical resistance. Therefore, as an alternative to steel pipe,
Tubes formed from resins such as polyphenylene sulfide, polyether-terketone, or fiber reinforced resins have been used.

[0004] However, tubes made of polyphenylene sulfide are inferior in chemical resistance, especially in concentrated nitric acid resistance, and have a high polyether sulfide resistance.
Terue-terketone tubes have the disadvantage of poor chemical resistance, especially concentrated sulfuric acid resistance. Further, the fiber reinforced resin tube has a problem that the manufacturing process is complicated and a pinhole is easily generated due to the manufacturing process of the material and the tube.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of conventional pipes and to provide a pipe excellent in chemical resistance and heat resistance.

[0006]

Means for Solving the Problems In order to achieve the above object, the present inventors have focused on a material for forming a pipe, particularly a material for forming an inner surface of a pipe which is in direct contact with a fluid in the pipe, and have studied diligently. As a result of the superposition, it was found that the above object can be achieved by using a styrene-based polymer having a syndiotactic structure or a material containing the polymer,
The present invention has been completed based on this finding.

That is, the present invention provides (1) a pipe characterized in that the inner surface is formed of a styrene-based polymer having a syndiotactic structure or a material containing the polymer, and (2) a pipe having a multilayer structure. It is intended to provide a tube according to the above (1), which is a tube.

[0008]

Embodiments of the present invention will be described below. The tube of the first invention in the present application is characterized in that the inner surface is formed of a styrene-based polymer having a syndiotactic structure or a material containing the polymer.

That is, a tube in which the inner surface of the tube which is in direct contact with the fluid flowing in the tube is formed of a styrene polymer having a syndiotactic structure or a material containing the polymer. The styrenic polymer having a syndiotactic structure used in the present invention is a syndiotactic structure having a stereochemical structure, that is, a phenyl group which is a side chain with respect to a main chain formed from carbon-carbon bonds is alternately formed. Is a styrenic polymer having a steric structure located in the opposite direction, and its tacticity is determined by nuclear magnetic resonance (13C-NMR) using isotope carbon.

The tacticity measured by the 13-NMR method is represented by the abundance ratio of a plurality of continuous structural units, for example, a dyad in the case of two, a triad in the case of three, and a pendant in the case of five. However, the styrenic polymer having a syndiotactic structure in the present invention is usually 75% by racemic dyad.
Polystyrene, poly (alkylstyrene), poly (halogenated styrene), poly (halogenated alkyl) having a syndiotacticity of 85% or more, preferably 30% or more, preferably 50% or more in racemic pendad Styrene), poly (alkoxystyrene), poly (vinyl benzoate), hydrogenated polymers thereof and mixtures thereof, or copolymers containing these as a main component.

Here, poly (alkylstyrene) includes poly (methylstyrene), poly (ethylstyrene), poly (isopropylstyrene), poly (tert-butylstyrene), poly (phenylstyrene) and poly (phenylstyrene). Vinyl (naphthalene), poly (vinylstyrene) and the like, and poly (halogenated styrene) includes poly (chlorostyrene), poly (bromostyrene) and poly (fluorostyrene).

The poly (halogenated alkylstyrene) includes poly (chloromethylstyrene) and the like, and the poly (alkoxystyrene) includes poly (methoxystyrene) and poly (ethoxystyrene). Among these, particularly preferred styrenic polymers include:
Polystyrene, poly (p-methylstyrene), poly (m
-Methylstyrene), poly (p-tert-butylstyrene), poly (p-chlorostyrene), poly (m-chlorostyrene), poly (p-fluorostyrene), hydrogenated polystyrene, and their structural units And a copolymer containing

For producing such a styrenic polymer having a syndiotactic structure, a known method may be adopted. For example, a titanium compound and a titanium compound are prepared in an inert hydrocarbon solvent or in the absence of a solvent. A method of polymerizing a styrene monomer using a condensation product of water and an alkylaluminum as a catalyst (Japanese Patent Application Laid-Open No. 62-1).
87708, etc.).

Poly (halogenated alkylstyrene) and hydrogenated polymers thereof are also prepared by known methods (JP-A-1-46912, JP-A-1-17885).
No. 05). The molecular weight of these polymers is not particularly limited, but usually those having a weight average molecular weight of 10,000 or more, especially 50,000 or more are preferably used.

The molecular weight distribution is not particularly limited with respect to its width, but Mw (weight average molecular weight) / Mn
Those having a (number average molecular weight) of 4 or less, preferably 3 or less are desirable. In the present invention, the weight average molecular weight is 10,
If it is less than 000, the intended purpose may not be sufficiently achieved, which is not preferable.

The degree of crystallinity of the styrenic polymer having a syndiotactic structure is not particularly limited. However, from the viewpoint of heat resistance and prevention of scale adhesion, the degree of crystallinity is 1%.
5% or more, preferably 25% or more, more preferably 3% or more
Desirably, it is 0% or more. In the present invention, as the material for forming the inner surface of the tube, only one kind of the styrene-based polymer having the syndiotactic structure may be used alone, or two or more kinds may be used in combination.

Further, other materials such as rubber may be included in addition to the polymer. Specific examples of other materials include natural rubber, polybutadiene, polyisoprene, polyisobutylene, neoprene, polysulfide rubber, thiocol rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, and styrene-butadiene. Block copolymer, hydrogenated styrene
Butadiene block copolymer (SEB), styrene-butadiene-styrene block copolymer, hydrogenated styrene-butadiene-styrene block copolymer (SEB)
S), styrene-isoprene block copolymer, hydrogenated styrene-isoprene block copolymer (SE (SE
P), styrene-isoprene-styrene block copolymer, hydrogenated styrene-isoprene-styrene block copolymer (SEPS), ethylene propylene rubber, ethylene propylene diene rubber, butadiene-acrylonitrile-styrene-core-shell rubber, methyl methacrylate
To-butadiene-styrene-core-shell rubber, methyl methacrylate-butyl acrylate-styrene-core-shell rubber, octyl acrylate-butadiene-acrylonitrile-styrene-core-shell rubber, butadiene-
Elastic materials such as styrene-core shell rubber, methyl methacrylate-butyl acrylate-siloxane, and the like, or modified products thereof may be used.

These elastic bodies may be used alone or in a combination of two or more. Further, in the present invention, as a material to be used in combination with the styrene-based polymer having a syndiotactic structure, in place of the elastic body or together with the elastic body, linear high-density polyethylene, linear low-density polyethylene, high-pressure method Low density polyethylene, isotactic polypropylene, syndiotactic polypropylene, block polypropylene,
Polyolefin resins such as random polypropylene, polybutene, 1,2-polybutadiene, cyclic polyolefin, and poly-4-methylpentene; polystyrene resins such as polystyrene and impact-resistant polystyrene; polycarbonate, polyphenylene ether, and polyphenylene Thermoplastic resins such as polyester resins such as sulfide, polyethylene terephthalate and polybutylene terephthalate, and polyamide resins such as polyamide 6 and polyamide 6,6 can be used.

In the present invention, an inorganic filler, a nucleating agent, a plasticizer, a release agent, a styrenic polymer having a syndiotactic structure, the above-mentioned elastic body, and the above-mentioned thermoplastic resin are added to
An antioxidant, a flame retardant, a flame retardant auxiliary, a pigment, an antistatic agent and the like can be added. As inorganic fillers, powders of carbon black, graphite, titanium dioxide, silica, calcium sulfate, calcium carbonate, barium carbonate, magnesium carbonate, magnesium sulfate, barium sulfate, tin oxide, alumina, kaolin, silicon carbide, glass, etc. Inorganic fillers, glass fibers, carbon fibers, carbon whiskers, potassium titanate whiskers, magnesia whiskers, silicon carbide whiskers, silicon nitride whiskers, zinc oxide whiskers, calcium carbonate whiskers, etc. Filler, plate-like inorganic filler such as mica, glass, talc, graphite and the like can be mentioned.

As a nucleating agent, aluminum di (pt-
Butylbenzoate), metal carboxylate, sodium methylenebis (2,4-di-t-butylphenol) acid phosphate, talc, phthalocyanine derivatives and the like. As a plasticizer, polyethylene glyco-
, Polyamide oligomers, ethylene bis stearamide, phthalic acid esters, polystyrene oligomers, polyethylene waxes, mineral oils, silicone oils and the like.

As the release agent, polyethylene wax,
Silicone oil, long-chain carboxylic acids, and metal salts of long-chain carboxylic acids are exemplified. Examples of the antioxidant include those based on phosphorus, phenol, and sulfur. As the flame retardant, brominated polystyrene, brominated syndiotactic polystyrene, brominated polyphenylene ether, brominated diphenylalkane, brominated diphenyl ether, phosphate ester, polyphosphoric acid, etc. And antimony trioxide.

Known pigments and antistatic agents can be used arbitrarily. In the present invention, when a styrene-based polymer having a syndiotactic structure is used in combination with an elastic material or a thermoplastic resin as another material as a material for forming the inner surface of the tube, a special restriction is imposed on the mixing ratio. However, the total amount thereof is usually 85 to 1% by weight, preferably 50 to 99% by weight, based on 15 to 99% by weight of the styrene polymer having a syndiotactic structure.
It is 50 to 10% by weight with respect to 90% by weight.

If the amount of the styrene-based polymer having a syndiotactic structure is less than 15% by weight, heat resistance may decrease, which is not desirable. When blending inorganic fillers, nucleating agents, plasticizers, mold release agents, antioxidants, flame retardants, flame retardant aids, pigments, antistatic agents, etc., there is no special restriction on the blending ratio, The compounding amount usually used may be sufficient.

Along with a styrenic polymer having a syndiotactic structure, an elastic material, a thermoplastic resin or an inorganic filler, a nucleating agent, a plasticizer, a release agent, an antioxidant, a flame retardant, a flame retardant auxiliary, a pigment, When an antistatic agent or the like is used, it is necessary to prepare a composition composed of these materials, but there is no particular limitation on the preparation method, and the composition can be prepared by a known method.

For example, these materials are used in ribbon blenders, Henschel mixers, Banbury mixers, drum tumblers, single screw extruders, twin screw extruders, multi-screw extruders, coneders, etc. The composition can be obtained by melt-kneading using the above. As the temperature at the time of melt-kneading, the melting point of the styrene-based polymer having a syndiotactic structure to be used is 350 ° C. or less, preferably the melting point of the polymer to be 330 ° C. or less. If the melting point is lower than the melting point of the polymer, the homogeneity of the composition may be deteriorated or the impact resistance may be lowered. If the temperature exceeds 350 ° C., the composition may be deteriorated.

The tube according to the first invention of the present application is a tube characterized in that its inner surface is formed of a styrene polymer having a syndiotactic structure or a material containing the polymer. It is not necessary to adopt a special method for manufacturing the pipe.For example, when the inner surface of the steel pipe is formed of a styrene polymer having a syndiotactic structure, the polymer is put in the steel pipe and the steel pipe is rotated. A method is adopted in which the polymer is heated and melted to apply the polymer.

In the case of producing a resin tube, a usual method, for example, an extrusion method is suitably employed. The tube in the present invention may be a single-layer tube using a styrene-based polymer having a syndiotactic structure or a material containing the polymer, or a styrene-based tube having an innermost layer having a syndiotactic structure. It may be a multi-layer tube made of a polymer or a material containing the polymer.

That is, the tube of the second invention in the present application is a multilayer tube characterized in that the innermost layer is formed of a styrene-based polymer having a syndiotactic structure or a material containing the polymer. This multilayer tube may be a two-layer tube in which the inner layer is formed of a styrene-based polymer having a syndiotactic structure or a material containing the polymer, and the outer layer is formed of a different material,
The inner layer is formed of a styrene-based polymer having a syndiotactic structure or a material containing the polymer,
The intermediate layer may be formed of a different material, and the outer layer may be a three-layer tube further formed of a different material.

That is, the number of layers of the multilayer tube of the present invention is not limited as long as at least the innermost layer is formed of a styrene polymer having a syndiotactic structure or a material containing the polymer. It is. The layers other than the innermost layer are not particularly limited, and a steel pipe can be used, and various other materials are used. Among them, a fiber reinforced resin having a thermosetting resin as a matrix is preferable.

Examples of the thermosetting resin include bisphenol type epoxy resin, novolak type epoxy resin,
Phenol resin, urea resin, melamine resin, unsaturated polyester resin, diallyl phthalate resin, polyimide resin and the like can be mentioned. These thermosetting resins are usually used together with a curing agent and, if necessary, a curing accelerator, and the curing agent and the curing accelerator are appropriately selected and used depending on the thermosetting resin to be used.

Suitable thermosetting resins include thermosetting epoxy resins. Examples of the curing agent include aliphatic amines, aromatic amines, tertiary amines, acid anhydrides, boron trifluoride-amine complexes. And phenol resin oligomers. Examples of the curing accelerator for the thermosetting epoxy resin include imidazoles and mercaptans.

The fibers used here include, for example, polyamide fibers, polyethylene terephthalate fibers, glass fibers, carbon fibers, aramid fibers, and ceramic (silicon carbide, boron, alumina, alumina-silica, etc.) fibers. Strength and high elasticity fibers are preferably used. A fiber-reinforced resin having a thermosetting resin as a matrix is formed into a sheet, nonwoven fabric, mat, woven fabric, or knitted fabric containing the above-mentioned fibers, impregnated with the thermosetting resin, and then dried by heating and curing. Obtainable.

When this fiber reinforced resin is used as at least one outer layer of a pipe, it may be a sheet, a nonwoven fabric, a mat, a woven fabric,
After impregnating the thermosetting resin into the fiber in the form of a knit,
Heat drying and semi-curing, winding around the tube forming the inner layer,
Thereafter, the outer layer is formed by completing the curing. The winding angle and thickness may be arbitrarily selected depending on the desired pipe.

As the outer layer, a fiber reinforced resin having a thermosetting resin as a matrix is preferable, but a thermoplastic resin may be used instead of the fiber reinforced resin or as a layer other than the outer layer. As the thermoplastic resin, polyethylene, polypropylene, polyvinyl chloride,
Examples include methacrylic acid resins, and engineering of polycarbonate, polyamide, polyacetal, polybutylene terephthalate, polyphenylene oxide, polyphenylene ether, polyether sulfone, polysulfone, polyphenylene sulfide, and the like. Plastics and the like.

When the outermost layer of the tube is to be plated, acrylonitrile-butadiene-styrene copolymer, polycarbonate and the like are preferred from the viewpoint of plating performance. According to the present invention, (1) a tube characterized in that the inner surface is formed of a styrene-based polymer having a syndiotactic structure or a material containing the polymer, and (2) a tube is a multilayer tube. A tube according to the above (1) is provided.

[0036]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. Example 1 A cylindrical tube having an outer diameter of 34 mm and a wall thickness of 3.5 mm was formed from a syndiotactic polystyrene ("Zarek" S100 manufactured by Idemitsu Petrochemical Co., Ltd.) using a tube extrusion molding machine.

The crystallinity of the syndiotactic polystyrene forming the inner surface of this tube was 40%. The obtained tube was cut into a length of 5 cm to prepare test pieces, and the test pieces were immersed in concentrated nitric acid and concentrated sulfuric acid at 50 ° C., respectively.
It was left for 24 hours. Then, the test piece was pulled out, washed with pure water, dried, and the inner surface of the tube was observed, but the change was not visible.

Example 2 In the same manner as in Example 1, the outer diameter was 34 mm and the wall thickness was 3.5 m.
m, a tube made of syndiotactic polystyrene having a length of 500 mm was formed. On the other hand, tensile strength of 320 kg / m
m ² and a pitch-based carbon fiber strand having a tensile modulus of 2000 Kg / mm, an epoxy resin [EP154 (7
0 parts by weight), EP828 (10 parts by weight), EP1001
(20 parts by weight)], a prepreg obtained by impregnating a curing agent dicyandiamide (5 parts by weight with respect to 100 parts by weight of epoxy resin) and 5 parts by weight of dichlorodimethylurea (basis weight: 100 g / m ² , resin content: 31.5 parts) % By weight).

This prepreg was wound around the above-mentioned molded tube made of syndiotactic polystyrene so as to form five layers, and then a heat-shrinkable tape was wound thereon. Tubes were manufactured. This multilayer tube was cut into a length of 5 cm to prepare a test piece, which was immersed in concentrated sulfuric acid at 50 ° C. and left for 24 hours. Subsequently, the test piece was pulled out, washed with pure water, dried, and the inner surface of the tube was observed, but the change was not visible, and the tube was smooth.

Comparative Example 1 A polyphenylene sulfide ("Photron" 020A9, manufactured by Polyplastics Co., Ltd.) was used.
It carried out similarly to Example 1.

The pipe immersed in concentrated nitric acid had many cracks on the inner surface of the pipe. Comparative Example 2 A stainless steel mandrel having an outer diameter of 27 mm and a length of 500 mm was prepared. On the other hand, an epoxy resin [EP154 (70 parts by weight), P828 (10 parts by weight), EP1001 (20 parts by weight)] is cured on a pitch-based carbon fiber strand having a tensile strength of 320 kg / mm ² and a tensile modulus of elasticity of 62000 kg / mm. Dicyandiamide (epoxy resin 10
Prepreg obtained by impregnating 5 parts by weight of dichlorodimethylurea (5 parts by weight with respect to 0 parts by weight) (100 g of basis weight)
/ M ² , resin content 31.5% by weight).

The prepreg was wound around the above-prepared mandrel so as to have 10 layers, and a heat-shrinkable tape was wound thereon, and was integrally cured at 130 ° C. for 2 hours and thermocompression-bonded. Next, pull out the mandrel and set the inner diameter to 27m.
m of epoxy resin tube was manufactured. The drawing process took a very long time.

This epoxy resin tube weighed 1.2 times the weight of the multilayer tube obtained in Example 2.
A test piece was prepared in the same manner as in Example 2 from an epoxy resin tube, and a test was performed in the same manner as in Example 2. The inner surface of the tube swelled and "roughened".

[0044]

According to the present invention, a pipe excellent in chemical resistance and heat resistance is provided, and is extremely useful as a pipe used for a machine tool and an apparatus in a chemical factory, a food manufacturing factory, a hot spring facility, and the like.

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) B32B 27/38 B32B 27/38 F term (Reference) 3H111 AA01 BA15 BA28 CB02 CB03 CB10 CC02 DA11 DA26 DB03 DB10 DB19 DB22 4F100 AK12B AK12K AK53A BA02 DA11 DG01A DH01A DH02A EH51 EJ42 EJ82A GB07 GB90 JB01 JJ03

Claims (4)

[Claims] 1. A tube having an inner surface formed of a styrenic polymer having a syndiotactic structure or a material containing the polymer. 2. The tube according to claim 1, wherein the tube is a multilayer tube. 3. The multilayer pipe according to claim 2, wherein at least one of the layers other than the innermost layer is formed of a fiber reinforced resin. 4. The multilayer pipe according to claim 3, wherein the fiber reinforced resin is a carbon fiber impregnated with an epoxy resin.