JPS6341136A - Vinylidene fluoride group composite pipe and manufacture thereof - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a vinylidene fluoride composite pipe and a method for manufacturing the same, particularly a vinylidene fluoride resin layer and a metal layer that have excellent chemical resistance, heat resistance, and corrosion resistance. The present invention relates to a vinylidene fluoride composite pipe that has good adhesion to other materials, and a method for manufacturing the same.

(Prior Art) Vinylidene fluoride resin is widely used as a material for circular pipes because it has excellent chemical resistance, heat resistance, and corrosion resistance, and can be easily molded at relatively low temperatures. However, vinylidene fluoride resin is expensive.

When this is used as a material for circular pipes, it is necessary to increase the wall thickness in order to provide sufficient pressure resistance.

The resulting circular tube is expensive.

For this reason, attempts have been made to coat metal surfaces with vinylidene fluoride resin to form composite pipes. but,
Vinylidene fluoride resin has poor adhesion to metals. Multi-unit pipes with vinylidene fluoride resin coated on the surface of the metal layer by powder resin coating have a certain adhesive strength, but because only a thin resin layer of 5 layers can be formed, pinholes are likely to occur in the resin layer. . Therefore, when a fluid such as hot water is passed through the composite pipe, the fluid may enter the metal layer through these pinholes, causing corrosion of the metal layer. JP-A No. 55-61961 discloses that after applying a primer made of an aqueous dispersion of vinylidene fluoride resin containing chromium ions and hydrogen ions to a metal surface, and adhering vinylidene fluoride resin powder thereon, , a method of heating and sintering this is disclosed. But this method also.

The process is complicated, and the resulting composite tube has pinholes that are typical of powder coating.

In addition, in the case of composite pipes made by lining metal with vinylidene fluoride resin, the adhesion between the two is weak and the lining layer may peel off, so there is no adhesion between the vinylidene fluoride resin layer and the metal layer. Proposals have been made to provide an agent layer to improve the adhesion between the two. For example,
-23713 publication describes polyester as an adhesive.
Epoxy compositions are used. Japanese Patent Publication No. 59-12
Publication No. 3621 discloses a composite pipe using an epoxy resin-acid anhydride curing agent as an adhesive. However, both adhesives are different types of adhesives from vinylidene fluoride resin, and the adhesive layer itself is inferior in durability.

Since uneven adhesion tends to occur, when applied to a composite pipe and hot water is flowed over a long period of time, disadvantages such as the resin layer peeling off from the metal layer or cracks appearing in the resin layer occur.

Therefore, attempts have been made to use compositions similar to vinylidene fluoride resins as adhesives.

Such compositions include, for example, vinylidene fluoride resin grafted with an ethylenically unsaturated compound (Japanese Patent Application Laid-open No.
84277) and vinylidene fluoride resin grafted with a polymer of acrylic acid or methacrylic acid (disclosed in JP-A-56-133309). As a result, a composite pipe in which the vinylidene fluoride resin layer and the metal layer have persistent adhesiveness can be obtained, but a grafting process of the vinylidene fluoride resin is required in the production of the composite pipe. Therefore, the manufacturing process is complicated.Moreover, the grafting process requires a large amount of solvent, making the resulting composite tube expensive.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems, and its purpose is to use vinylidene fluoride which has good adhesiveness between the vinylidene fluoride resin layer and the metal layer. An object of the present invention is to provide a system composite pipe and a method for manufacturing the same. Another object of the present invention is to provide a vinylidene fluoride composite pipe with excellent chemical resistance, heat resistance, and corrosion resistance, and a method for manufacturing the same. Still another object of the present invention is to provide a vinylidene fluoride 7ide composite pipe and a method for manufacturing the same, which have excellent water quality and sanitary properties since the fluid to be passed through the pipe is free from contamination with impurities. Still another object of the present invention is to provide a method for manufacturing a vinylidene fluoride composite pipe using simple steps.

(Means for Solving the Problems) According to the present invention, the inner surface of a tubular metal layer is coated with a composition containing a vinylidene fluoride resin and an organosilicon compound which have been irradiated with ionizing radiation in advance.

Further, by coating the inner surface with vinylidene fluoride resin, the vinylidene fluoride resin layer and the metal layer are firmly bonded. It was completed based on the inventor's knowledge.

The vinylidene fluoride composite pipe of the present invention includes (1) a metal layer, (2) a vinylidene fluoride resin that coats the inner surface of the metal layer and has been irradiated with ionizing radiation in advance, and an organosilicon compound represented by the following formula. a first inner layer formed from a vinylidene fluoride composition containing.

here.

R is an olefinic hydrocarbon group.

Y is a hydrolyzable organic group, and R' is R or Y.

(3) a second inner layer made of vinylidene fluoride resin and covering the inner surface of the first inner layer, thereby achieving the above object.

Another vinylidene fluoride composite pipe of the present invention includes (1) a metal layer, and (2) a vinylidene fluoride resin that coats the inner surface of the metal layer and is irradiated with ionizing radiation in advance.

A first inner layer formed from a vinylidene fluoride composition containing an organosilicon compound represented by the following formula and an organic filler and/or an inorganic filler.

here.

R is an olefinic hydrocarbon group.

Y is a hydrolyzable organic group, and Ro is R or Y.

(3) a second inner layer made of vinylidene fluoride resin and covering the inner surface of the first inner layer, thereby achieving the above object.

The method for manufacturing such a composite tube includes the steps of continuously forming a metal sheet into a circular tube shape, and welding the ends of the circular tube, while forming the first inner layer using a vinylidene fluoride composition. and a step of sequentially extruding vinylidene fluoride resin forming the second inner layer onto the inner surface of the circular tube, thereby achieving the above object.

By irradiating vinylidene fluoride resin with ionizing radiation in advance, radicals are generated within the resin, and in a composition containing this vinylidene fluoride resin and an organosiliconized metal, the generated radicals cause an organosilicon compound to form. It is thought that the graft polymerization of the polyvinylidene fluoride onto the vinylidene fluoride resin progresses.

Since the organosilicon compound that becomes the graft chain has excellent adhesion to metal, the grafted vinylidene fluoride resin composition can be firmly adhered to the inner surface of the metal layer. Moreover,
This composition maintains the chemical resistance, heat resistance, and corrosion resistance of vinylidene fluoride resin. Therefore, a composite tube with good adhesiveness between the vinylidene fluoride resin layer and the metal layer can be obtained.

However, this composition contains unreacted organosilicon compounds.
Since it contains impurities such as substances, when a fluid (for example, hot water) is passed through the obtained composite pipe, there is a risk that the impurity will be mixed into the fluid. Contamination with impurities impairs the water quality and hygiene of the composite pipe. Moreover, since the vinylidene fluoride resin undergoes oxidative deterioration due to grafting, the heat resistance of the resin decreases. Therefore, the inner surface of the grafted vinylidene fluoride resin N (first inner layer) is further coated with vinylidene fluoride resin (second inner layer) to prevent contamination of impurities and deterioration of heat resistance. The grafted vinylidene fluoride resin not only has excellent adhesion to metals as described above, but also has good adhesion to vinylidene fluoride resin. This is because the grafted vinylidene fluoride resin is the same type of composition as the vinylidene fluoride resin.

The vinylidene fluoride resin used in the first inner layer and the second inner layer refers to a vinylidene fluoride homopolymer and a copolymer of vinylidene fluoride and another monomer. Monomers include ethylene, propylene, vinyl chloride, and tetrafluoroethylene.

There are halogenated ethylenes such as dichlorofluoroethylene and 1.1.2-trifluoro-2-chloroethylene. Such monomers are contained in the copolymer in a proportion of 5 mol% or less. If it exceeds 5 mol%, the properties of the vinylidene fluoride resin will be impaired. As a commercially available product,
Examples include KF Polymer (manufactured by Kureha Kagaku Co., Ltd.) and Kynar (manufactured by Pennwalt Co., Ltd.). The vinylidene fluoride resin used for the second inner layer preferably has the same composition as the resin for the first inner layer from the viewpoint of adhesion to the first inner layer.

Examples of ionizing radiation include β rays, γ rays, and α rays.

There are neutron beams, X-rays, and accelerated electron beams, especially gamma rays.

An accelerated electron beam is preferred. Gamma rays are preferable for granular vinylidene fluoride resin. A sheet of vinylidene fluoride resin is continuously irradiated with an electron beam and then pelletized. The radiation dose is said to be 0.1 megarad or more. If it is less than 0.1 Megara, the desired adhesion to metal cannot be obtained even if an organosilicon compound is added and mixed in a subsequent step. Although there is no particular limit to the maximum dose, if a large amount of irradiation is applied, vinylidene fluoride resin will decompose.

As a result, the resin becomes colored and deteriorates, which is undesirable.

The silicon compound has alkoxy groups, acyloxy stores,
It contains hydrolyzable organic groups such as oxime groups and substituted amino groups and olefinic hydrocarbon groups. For such organosilicon compounds.

Examples include vinyltrimethoxysilane and vinyltriethoxysilane. The organosilicon compound is contained in an amount of 0.1 to 10 parts by weight, preferably 0.3 to 5 parts by weight, based on 100 parts by weight of vinylidene fluoride resin. If the amount is less than 0.1 part by weight, desired adhesiveness between the vinylidene fluoride resin layer and the metal layer cannot be obtained.

If it exceeds 10 parts by weight, the adhesiveness will not improve much and the properties of the vinylidene fluoride resin will be impaired.

Any known metal can be used for the metal layer.

Examples include aluminum and its alloys, iron and its alloys, stainless steel, copper and its alloys. The surface of the metal layer is preferably cleaned with acid, alkali, detergent, organic solvent, or the like. Surface treatments such as chemical conversion treatment and oxidation treatment may also be performed.

Furthermore, blasting, sandpapering, plating, thermal spraying, or the like may be applied. However, conventional etching and treatment with vinylidene fluoride primer are not necessary.

An organic or inorganic filler may be further added to the composition forming the first inner layer in order to improve adhesion to metal. Vinylidene fluoride resin, which is the main component of the first inner layer, has a large coefficient of linear expansion.

Therefore, the adhesiveness decreases due to the difference in linear expansion coefficient with the metal. The linear expansion coefficient of vinylidene fluoride resin is (0,
7-1.5) Xl0-'/'C, aluminum is 0.23X10-'/'c, and iron is 0.11
X 10-'/°C. In particular, when the composite tube of the present invention is used for hot water, there is a risk that the first inner layer will peel off from the metal layer due to this difference in linear expansion coefficient. Therefore, it is necessary to lower the linear expansion coefficient of the vinylidene fluoride resin to bring it closer to that of the metal, thereby increasing the adhesiveness between the metal layer and the first inner layer. Therefore.

As the organic or inorganic filler, a substance that lowers the coefficient of linear expansion of the vinylidene fluoride resin is used. Organic fillers include 2. For example, phenolic resin.

There are thermosetting resin powders such as melamine resins, organic fibers such as carbon fibers and aramid fibers, graphite, and wood flour. Examples of inorganic fillers include 1.

Inorganic fine powder such as talc, mica, calcium carbonate,
There are inorganic fibers such as glass fiber and potassium titanate fiber. The amount of organic or inorganic filler is 100 parts by weight or less, preferably 5 parts by weight, based on 100 parts by weight of vinylidene fluoride resin.
It is added in an amount of 100 parts by weight. If it exceeds 100 parts by weight, the properties of the vinylidene fluoride resin will be impaired.

Addition of fillers.

It may be used either during mixing or during melt-kneading.

Thus, the composite tube of the present invention having a metal layer, a first inner layer, and a second inner layer is optionally provided with an outer layer on the outer surface of the metal layer in order to protect the metal layer.

For example, as shown in FIG. 1, a composite pipe A of the present invention has a metal layer 3. A first layer covering the inner surface of this metal layer 3
Inner layer 1. A second inner layer 2 covering the inner surface of this inner layer 1.
and outer N4 covering the outer surface of the metal layer 3.

The first inner layer 1 is formed from a vinylidene fluoride resin that has been irradiated with ionizing radiation in advance and a vinylidene fluoride composition containing the organosilicon compound. Second
The inner layer 2 is made of vinylidene fluoride resin. The outer layer 4 may be formed of other resins besides vinylidene fluoride resin.

Such a composite tube is manufactured in two steps, for example, according to the continuous manufacturing apparatus shown in FIG.

(Left below) Band-shaped metal sheet 50 pulled out from uncoiler 5
is bent by a U-shaped forming machine 6 into a U-shape in which each side extending in the longitudinal direction faces each other. The metal sheet 51 bent into a U-shape is further formed into a circular tube 52 having a perfect circular cross section by a circular tube forming machine 7. The overlapping portion of the circular tubes 52 formed by the circular tube forming machine 7 is welded by the welding machine 8.

The vinylidene fluoride composition and the vinylidene fluoride resin are sequentially extruded onto the inner peripheral surface of the circular tube 52 by the inner surface resin coating device 70 disposed inside the U-shaped metal sheet 51 and inside the circular tube 52. Then, the inner peripheral surface is coated with a first inner layer and a second inner layer.

The resin-filled lower 10 of the inner surface resin coating device 70 is connected to a first inner layer extruder 711 and a second inner layer extruder a712. The resin extruded from the first inner layer extruder @ 711 and the second inner layer extruder 712 is transferred to the circular tube 5 by the inner surface resin coating device 70 through different routes, respectively.
It is pushed out to the inner peripheral surface of 2. Thereby, the inner peripheral surface is coated with the first inner layer and the second inner layer. The first inner layer resin and the second inner layer resin are used in the inner surface resin coating device 70.
The resin may be combined within the inner layer and coated as two layers of resin, or after the first inner layer is coated, the second inner layer may be coated on the inner surface thereof. The outer peripheral surface of the circular tube 52 coated with the first inner layer and the second inner layer is further coated with resin by the outer surface coating device 9 as necessary.

A circular tube (composite tube) 53 whose inner and outer circumferential surfaces are coated with resin is taken by the take-up machine IO and the cutting machine 11.

A composite tube of desired length is formed.

In the above method for manufacturing a composite pipe, in order to improve the adhesiveness between the vinylidene fluoride resin layer and the metal layer.

A cleaning process, a surface treatment process, and a heating process may be provided before coating with the resin. Moreover, it is preferable to heat the circular tube 52 even before welding in order to improve the stability of welding and the adhesiveness between the metal layer and the first inner layer.

In such a method for manufacturing a composite pipe, the vinylidene fluoride composition forming the first inner layer is prepared after sufficiently mixing a vinylidene fluoride resin and an organosilicon compound that have been irradiated with ionizing radiation in advance.

It is supplied to the first inner layer extrusion a 711. but.

After this mixing, the mixture may be further melt-kneaded and supplied in the form of a kneaded product. For melt admixture, j! A kneading machine such as an e-shaft or twin-shaft press ratio machine, a Benbury mixer, etc. is used. The kneading temperature is preferably 150 to 250°C.

If the temperature is lower than 150° C., the vinylidene fluoride resin will not melt, so that the vinylidene fluoride resin and the organosilicon compound will not be sufficiently kneaded. If the temperature exceeds 250°C, the vinylidene fluoride resin becomes noticeably colored during melt-kneading, and the decomposition reaction is accelerated.

As a result, toxic substances such as hydrofluoric acid are generated. The kneading time is not particularly limited, but if kneaded for too long,
Decomposition of vinylidene fluoride resin occurs. The melt-kneaded product is
Once cooled and solidified, it is made into granules.

It is supplied to a first inner layer extruder 711. For the kneaded material,
Additives such as antioxidants and ultraviolet absorbers may also be added.

A method for manufacturing a composite tube of the present invention includes one such method of manufacturing a vinylidene fluoride resin composition to form a composite tube of the present invention.

It is applicable only to compositions with good adhesion to metals.

(Example) The present invention will be described below with reference to examples.

Vinylidene fluoride resin powder (KF Polymer" 1100)
(manufactured by Kureha Kagaku Co., Ltd.) in a polyethylene container.

γ-rays (C06°) were irradiated at 1 megarad in air.

To 100 parts by weight of this vinylidene fluoride resin, 2 parts by weight of vinyltrimethoxysilane (VTS-M, manufactured by Chi-7so Corporation) was added and mixed for 5 minutes using a Henschel mixer.

The mixture was supplied to a first inner layer extruder a711, and the vinylidene fluoride resin powder was supplied to a second inner layer extruder 712.

An aluminum-magnesium alloy coil having a width of 140mm and a thickness of 0.4*n was fixed to the uncoiler 5.

The strip-shaped aluminum alloy sheet 50 pulled out from the uncoiler 5 is surface-treated with a 10% hydrochloric acid solution at 50°C. It was bent into a U-shape in which the side parts extending in the direction faced each other. The aluminum alloy sheet 51 bent into a U-shape is further heat-treated at 300°C, and a circular tube forming machine 7 is used to form a circular tube 52 (inner diameter 43 mm) with a perfect circular cross section.
It was molded into. The overlapped portions of the circular tubes 52 formed by the circular tube forming machine 7 are welded [8], and an inner surface resin disposed from the inside of the U-shaped aluminum alloy sheet 51 to the inside of the circular tube 52 is welded [8]. The coating device 70 coats the circular tube 52 at 220°C.
A vinylidene fluoride composition and a vinylidene fluoride resin were sequentially extruded onto the inner circumferential surface of the tube to coat the inner circumferential surface with the first inner layer and the second inner layer. The vinylidene fluoride composition and the vinylidene fluoride resin are supplied in advance to the first inner layer extruder 711 and the second inner layer extruder 712, respectively, as described above. The barrel temperature of the extruder was 230°C in all cases.

On the outer peripheral surface of the circular tube 52 whose inner surface is coated in this way.

The composite tube 53 was coated with vinylidene fluoride resin at 230° C. using the outer surface coating device 9. Composite pipe 53.

It was cut into a desired length using a pulling machine 10 and a cutting machine 11. In the continuous manufacturing process of these composite pipes.

The speed of the production line was 1 m/win.

The obtained composite tube had an inner diameter of 40 fins and an outer diameter of 45 mm.

The thickness of the first inner layer is 0.5 mm, and the thickness of the second inner layer is 1 mm.
The thickness of the dragon and outer layer was 0.6 gn. When this composite pipe was subjected to a peel test, the result was 8.5 kg/
A peel strength of 2 cm (adhesion strength per 2 marks in width) was obtained.

Furthermore, the heat resistance, adhesion, water quality, and sanitary properties of the composite pipe were tested in the following manner.

fl) Temperature Difference Test While 95°C hot water was flowing through the inside of a composite pipe cut into 1 m length, the entire pipe was immersed in a 65°C hot water bath. After the composite tube was left for 500 hours with a temperature difference in the thickness direction, the inner surface of the tube was observed, and no abnormality was found.

(2) Heat cycle test 120℃ steam and 20℃
C. cold water was alternately passed through the tube for 5 minutes each. After conducting the test for 1000 cycles with 10 minutes as one cycle, the inner surface of the tube was observed, and although a bulge with a diameter of approximately 11111 was observed, there was no abnormality in the adhesion between the first inner layer and the aluminum alloy layer.

(3) Dissolution test (water hygiene) The water hygiene of the composite pipe was tested using JISK6776-87 (
When measured according to the standard for heat-resistant hard vinyl chloride pipes, the consumption of potassium permanganate was 0.9■/7! Met.

These results are shown in the table below.

Irradiation of main T-ray with one tip! A composite tube was obtained in the same manner as in Example 1, except that l, '1ffi was set to 3 megarads. The peel strength of the resulting composite tube was 8.7 kg/2 cm.

When this composite tube was subjected to the same test as in Example 1, no abnormality was observed in the temperature difference test.

Although blistering was observed after a diameter of 1 mm in the heat cycle test, there was no abnormality in the adhesiveness between the first inner layer and the aluminum alloy layer. The amount of potassium permanganate consumed in the dissolution test was 1.4 μ/l. These results are shown in the table below.

Example 1 except that 20 parts by weight (based on 100 parts by weight of vinylidene fluoride resin powder) of mica (Sujirite Mica" 20011, manufactured by Kuraray Co., Ltd.) was further added to the mixture as an inorganic filler. A composite tube was obtained in the same manner as in Example 1.The peel strength of the obtained composite tube was 8.5 kg/2cm.The same test as in Example 1 was conducted on this composite tube, and the result was a temperature difference test, a thermal No abnormality was observed in the cycle test.

The amount of potassium permanganate consumed in the dissolution test was 0.7■
/l.

1 width 14 (I
Except for using a cold-rolled steel plate with a thickness of 0.2 mm and a thickness of 0.2 mm.
A composite tube was obtained in the same manner as in Example 1. The peel strength of the obtained composite tube was 6.0 kg/2 cm. When this composite pipe was subjected to the same test as in Example 1, a bulge with a diameter of around 1 mm occurred in the temperature difference test.
Although in the heat cycle test, bulges with a diameter of around 2mm were observed with an area ratio of about 5%.

There was no abnormality in the adhesion between the first inner layer and the aluminum alloy layer. The amount of potassium permanganate consumed in the dissolution test was 1.
3mg/j! Met.

These results are shown in the table below.

Although an attempt was made to manufacture a composite tube in the same manner as in Example 1 except that γ-rays were not irradiated, the first inner layer and the metal layer did not adhere at all.

These results are shown in the table below.

Spot I: Except for not using vinyltrimethoxysilane,
A composite tube was obtained in the same manner as in Example 1. The peel strength of the resulting composite tube was 0.8 kg/2cn+. The same tests as in Example 1 were conducted on this composite tube. In both cases, the first inner layer and the second inner layer were completely removed from the metal layer in 24 hours in the 7 temperature difference test and in 30 cycles in the thermal cycle test. Peeled off. The amount of potassium permanganate consumed in the dissolution test was 0.6 μ/l.

These results are shown in the table below.

Construction Comparison (1) A composite pipe was obtained in the same manner as in the example construction except that the thickness of the first inner layer was 1.51 m and the second inner layer was not coated. The strength of the resulting composite tube is ff1ll:4.

It was 8.6 kg/2 cm. When this composite tube was subjected to the same tests as in Example 1, no abnormality was observed in the temperature difference test, and although a bulge around 1 inch in diameter was observed in the heat cycle test, the first inner layer and aluminum alloy layer There was no abnormality in the adhesion with.

However, the inner layer was yellowed after the test. In addition, the consumption amount of potassium permanganate in the dissolution test was 10.9 μ/1.

These results are shown in the table below.

After sandblasting the inner surface of a steel pipe with an inner diameter of 80mm and a thickness of 31mm, we applied vinylidene fluoride resin (Polyflon TFE Enamel EK-19) as a primer to that surface.
58GG (manufactured by Daikin) was applied with a brush. When this was dried at room temperature for 1 hour, a coating film of about 30 μm was obtained. Add vinylidene fluoride resin (Neoflon FEP, manufactured by Daikin) on top of the paint film.

Deposited by powder coating at 380°C, 200°C
A μI vinylidene fluoride resin film was formed.

After heat treating the resulting composite tube at 350°C for 2 hours.

A temperature difference test similar to that in Example 1 was conducted.

In 50 hours, the bulge with a diameter of around 4 liters increased to 20% in terms of area ratio.
The vinylidene fluoride resin film was completely peeled off from the steel pipe after 100 hours.

(Left below) As is clear from the Examples and Comparative Examples, the vinylidene fluoride composite pipe of the present invention can be obtained through a simple process and has excellent adhesion between the vinylidene fluoride resin layer and the metal layer. ing. Almost no abnormalities were observed in temperature difference tests or thermal cycle tests, and the heat resistance was also good. If the vinylidene fluoride resin layer contains mica as an inorganic filler, the heat resistance will be further improved. Moreover, even in the dissolution test, there was only a small amount of eluate, and the water quality and sanitary properties are also excellent.

A composite tube that does not contain vinyltrimethoxysilane (organosilicon compound) in the first inner layer or uses vinylidene fluoride resin that is not irradiated with gamma rays.

Adhesion between the vinylidene fluoride resin layer and the metal layer is poor. Composite tubes that were not coated with a second inner layer.

Although the adhesion between the resin layer and the metal layer is excellent.

A large amount of eluate was obtained in the dissolution test, resulting in poor water quality and hygiene. The composite tube was obtained by a conventional powder coating method in which vinylidene fluoride resin powder was deposited on a coating of vinylidene fluoride primer.

Adhesion between the resin layer and metal layer is poor.

(Effects of the Invention) According to the present invention, a composite pipe with good adhesiveness between the vinylidene fluoride resin layer and the metal layer can be obtained. This composite pipe has chemical resistance and chemical resistance, which is a characteristic of vinylidene fluoride resin.
Excellent heat resistance and corrosion resistance. Water quality and hygiene are also good. The method for manufacturing a composite tube is simple, and the length and diameter of the tube can be set arbitrarily, so the resulting composite tube is inexpensive. Therefore, the composite pipe of the present invention can be effectively used as a piping material for hot water supply, a pipe for distributing chemicals at high temperatures, a plant material, a clean pipe, and the like.

4. Figure 1 is a cross-sectional front view showing one embodiment of the composite pipe of the present invention, and Figure 2 is a schematic diagram showing the apparatus for manufacturing the composite pipe of Figure 1.

l...first inner layer, 2...second inner layer, 3...metal layer.

4...Outer layer, 5...Uncoiler-26...U-shaped molding machine.

7... Circular tube forming machine, 8... Welding machine, 9... Outer surface coating device.

DESCRIPTION OF SYMBOLS 10... Taking machine, 11... Cutting machine, 50... Metal sheet, 51... Metal sheet 52 bent into a U-shape
...Circular pipe, 53...Circular pipe (?j! Joint pipe main pipe 70...
・Inner surface resin coating device, 710...Resin inlet, 711・
...First inner layer extruder, 712...Second inner layer extruder.

that's all Applicant: Director of the Agency of Industrial Science and Technology II, Figure 1 Figure 2

Claims (1)

[Claims] 1. (1) a metal layer; (2) a metal layer that coats the inner surface of the metal layer and contains a vinylidene fluoride resin that has been irradiated with ionizing radiation in advance and an organosilicon compound represented by the following formula; a first inner layer formed from a vinylidene fluoride composition; Or Y. (3) A vinylidene fluoride composite pipe comprising a second inner layer made of vinylidene fluoride resin and covering the inner surface of the first inner layer. 2. The first inner layer is made of the vinylidene fluoride resin 10
0.1 to 10 parts by weight of the organosilicon compound
The vinylidene fluoride composite pipe according to claim 1, which is formed from a composition containing within the range of parts by weight. 3. The vinylidene fluoride composite pipe according to claim 1, wherein the dose of the ionizing radiation is 0.1 megarad or more. 4. The vinylidene fluoride composite pipe according to claim 1, wherein the organosilicon compound is at least one of vinyltrimethoxysilane and vinyltriethoxysilane. 5. The vinylidene fluoride composite tube according to claim 1, wherein the ionizing radiation is at least one of β rays, γ rays, α rays, neutron beams, X-rays, and accelerated electron beams. 6. (1) a metal layer; (2) a vinylidene fluoride resin that coats the inner surface of the metal layer and has been irradiated with ionizing radiation in advance, an organosilicon compound represented by the following formula, and an organic filler and/or an inorganic a first inner layer formed from a vinylidene fluoride composition containing a filler; and R' is R or Y. (3) A vinylidene fluoride composite pipe, comprising: a second inner layer made of vinylidene fluoride resin and covering the inner surface of the first inner layer. 7. The first inner layer is made of the vinylidene fluoride resin 10
0.1 to 10 parts by weight of the organosilicon compound
7. The vinylidene fluoride composite pipe according to claim 6, which is formed from a composition containing within the range of parts by weight. 8. The vinylidene fluoride composite pipe according to claim 6, wherein the dose of the ionizing radiation is 0.1 megarad or more. 9. The vinylidene fluoride composite pipe according to claim 6, wherein the organosilicon compound is at least one of vinyltrimethoxysilane and vinyltriethoxysilane. 10. The vinylidene fluoride composite tube according to claim 6, wherein the ionizing radiation is at least one of β rays, γ rays, α rays, neutron beams, X-rays, and accelerated electron beams. 11, the first inner layer is made of the vinylidene fluoride resin 1
7. The vinylidene fluoride composite pipe according to claim 6, which is formed from a composition containing the organic filler and/or inorganic filler in a ratio of 100 parts by weight or less to 00 parts by weight. 12. Claim 6, wherein the organic filler is at least one of thermosetting resin powder such as phenolic resin and melamine resin, organic fiber such as carbon fiber and aramid fiber, graphite, and wood flour. The vinylidene fluoride composite pipe described in . 13. The fluoride according to claim 6, wherein the inorganic filler is at least one of inorganic fine powders such as talc, mica, and calcium carbonate, inorganic fibers such as potassium titanate fibers, and glass fibers. Vinylidene composite pipe. 14, (1) a metal layer; (2) a vinylidene fluoride composition containing a vinylidene fluoride resin coated on the inner surface of the metal layer and irradiated with ionizing radiation in advance and an organosilicon compound represented by the following formula; The first inner layer formed, ▲ includes mathematical formulas, chemical formulas, tables, etc. ▼ where R is an olefinic hydrocarbon group, Y is a hydrolyzable organic group, and R' is R or Y. (3) A method for producing a vinylidene fluoride-based composite pipe having a second inner layer formed from a vinylidene fluoride resin and covering the inner surface of the first inner layer, the method comprising continuously rolling a metal sheet in a circle. A process of forming the circular tube into a tubular shape, and while welding the ends of the circular tube, the vinylidene fluoride composition forming the first inner layer and the vinylidene fluoride resin forming the second inner layer are added to the circular tube. A method for manufacturing a vinylidene fluoride composite pipe, which includes the step of sequentially extruding the inner surface. 15, the first inner layer is made of the vinylidene fluoride resin 1
0.1 to 1 part by weight of the organosilicon compound
15. The method for producing a vinylidene fluoride composite pipe according to claim 14, which is formed from a composition containing 0 parts by weight. 16. The method for manufacturing a vinylidene fluoride composite pipe according to claim 14, wherein the dose of the ionizing radiation is 0.1 megarad or more. 17. The method for producing a vinylidene fluoride composite pipe according to claim 14, wherein the organosilicon compound is at least one of vinyltrimethoxysilane and vinyltriethoxysilane. 18. The vinylidene fluoride composite tube according to claim 14, wherein the ionizing radiation is at least one of β rays, γ rays, α rays, neutron beams, X rays, and accelerated electron beams. Production method. 19, (1) a metal layer; (2) a vinylidene fluoride resin that coats the inner surface of the metal layer and has been irradiated with ionizing radiation in advance, an organosilicon compound represented by the following formula, and an organic filler and/or an inorganic a first inner layer formed from a vinylidene fluoride composition containing a filler, where R is an olefinic hydrocarbon group, Y is a hydrolyzable organic group, and R' is R or Y; (3) A method for manufacturing a vinylidene fluoride-based composite pipe, comprising: a second inner layer covering the inner surface of the first inner layer and formed from a vinylidene fluoride resin, the method comprising: continuously rolling a metal sheet in a circle; A process of forming the circular tube into a tubular shape, and while welding the ends of the circular tube, the vinylidene fluoride composition forming the first inner layer and the vinylidene fluoride resin forming the second inner layer are added to the circular tube. A method for manufacturing a vinylidene fluoride composite pipe, which includes the step of sequentially extruding the inner surface. 20, the first inner layer is made of the vinylidene fluoride resin 1
0.1 to 1 part by weight of the organosilicon compound
20. The method for producing a vinylidene fluoride composite pipe according to claim 19, which is formed from a composition containing 0 parts by weight. 21. The method for manufacturing a vinylidene fluoride composite pipe according to claim 19, wherein the dose of the ionizing radiation is 0.1 megarad or more. 22. The method for manufacturing a vinylidene fluoride composite pipe according to claim 19, wherein the organosilicon compound is at least one of vinyltrimethoxysilane and vinyltriethoxysilane. 23. The vinylidene fluoride composite tube according to claim 19, wherein the ionizing radiation is at least one of β rays, γ rays, α rays, neutron beams, X rays, and accelerated electron beams. Production method. 24, the first inner layer is made of the vinylidene fluoride resin 1
Production of a vinylidene fluoride composite pipe according to claim 19, which is formed from a composition containing the organic filler and/or inorganic filler in a ratio of 100 parts by weight or less to 00 parts by weight. Method. 25. Claim 19, wherein the organic filler is at least one of thermosetting resin powder such as phenolic resin and melamine resin, organic fiber such as carbon fiber and aramid fiber, graphite, and wood flour. A method for producing a vinylidene fluoride composite pipe as described in . 26. The fluoride according to claim 19, wherein the inorganic filler is at least one of inorganic fine powders such as talc, mica, and calcium carbonate, inorganic fibers such as potassium titanate fibers, and glass fibers. A method for manufacturing vinylidene composite pipes.