JPH0478533A - Tube and preparation of tube-coated cylindrical product - Google Patents

Abstract

PURPOSE:To obtain a tube-coated cylindrical product with an extremely good surface accuracy by forming a resin film wherein a heat-resistant resin is a main ingredient on the inner surface of a tube made of a fluorinated resin having heat fusing characteristics. CONSTITUTION:A resin film wherein a heat-resistant resin is a main ingredient is formed on the inner surface of a tube made of a fluorinated resin having heat fusing characteristics. A tube provided with a heat-resistant resin film with a sufficient heat fusing characteristics without applying an undercoating treatment such as a primer in advance to a cylindrical product and a cylindrical product coated with a tube made of a fluorinated resin with an extremely good surface accuracy are obtd. In addition, a resin film wherein the heatresistant resin in a main ingredient is formed on the inner surface of a tube made of a fluorinated resin with heat fusing characteristics and a tube formed on the cylindrical product is coated therewith and is dried. The cylindrical body formed of the fluorinated resin into a tube-like product has heat-shrinking properties and it shrinks usually by 0-25% in the radial direction at 300 deg.C, pref. about 5-15% and by 25% or less in the axial direction, pref. about 0-5%. As the heat-resistant resin, polyparabanic acid resin and polymide resin are pref.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a tube made of a fluororesin having heat-sealable properties, on which a heat-resistant resin film is formed on the inner surface, and a tube made of a fluororesin on the surface thereof. The present invention relates to a method for manufacturing a tube-covered cylindrical article formed by firmly fusion bonding.

(Prior art) Fluorine-based resins have been widely used in recent years as coating materials for various rolls, including heat-fixing rolls for electronic copying machines, as they have excellent properties such as non-adhesiveness, corrosion resistance, chemical resistance, and heat resistance. has been done.

By the way, as methods for coating articles with fluororesin, there are two known methods: a so-called coating method in which a fluororesin powder paint or a dispersion paint is applied and then baked, and a sheet lining method in which a fluororesin film or sheet is pasted. However, with the former method, it is difficult to obtain a uniform, smooth, and thick coating layer; for example, even if a layer of about 50 μm is to be obtained, the diversion coating method requires three or more layers of coating. There are problems such as, even when powder coating is used, the coating thickness of several hundred microns is 1
It is difficult to obtain a smooth coating, and the processing cost is high.

Furthermore, in the sheet lining method, an adhesive method is also considered, in which the fluororesin surface is treated in advance to enable adhesion with an adhesive, and then a general resin adhesive such as epoxy resin is used as the base. It is bonded to materials.

However, with this method, the essential characteristics of fluororesins such as heat resistance, chemical resistance, cold resistance, weather resistance, etc. are reduced to the properties of adhesives. That is, there is a fundamental problem in that the long-awaited advantages of fluororesins are lost.

Another known method of coating with fluororesin is to cover the article with a heat-shrinkable tube made of fluororesin, then heat it to shrink the tube, and fix it to the article simply by the shrinkage force. However, since this method only creates close contact between the coating layer and the article, if force is applied to the tube, the tube may become twisted or wrinkled, or even if the tube is used, it may tear. There is a problem with doing so.

A method that can solve these problems is to shrink and fix a heat-shrinkable tube made of fluororesin to the surface of a cylindrical article that has been previously treated with a primer, and then heat it to a temperature above the melting point of the fluororesin. A method of fusion-bonding has also been proposed. (Japanese Unexamined Patent Publication No. 1534/1983). This method can be said to be an excellent method in that it does not cause the above-mentioned problems and it is possible to easily obtain a cylindrical article such as a roll having a fluororesin film.

(Problems to be Solved by the Invention) However, the brimer treatment agent disclosed in JP-A-64-1534 mentioned above mainly contains an aqueous solution containing tetrafluoro(alkyl vinyl ether) copolymer colloidal particles and polyamic acid. An embodiment using a dispersion liquid is exemplified, but since the embodiment exemplified here uses an aqueous dispersion liquid as described above, the coating tends to be uneven and thickness unevenness tends to occur. To improve these points, it was necessary to strictly control the viscosity of the treatment solution and the coating process. Furthermore, since it is a simple dispersion, the dispersed particles may aggregate and form surface protrusions during coating, so it is rather unsuitable for industrial mass production.

For example, heat rolls used for fusing in electronic copying machines require extremely high surface precision, so it is necessary to narrow the tolerance range for thickness unevenness, and small convex surface protrusions can also affect images. The method disclosed in Japanese Patent Application Laid-Open No. 1534-1986 has another drawback, such as the fact that it is not allowed because

In view of the above-mentioned problems, the present invention provides a tube comprising a heat-resistant resin film that has sufficient thermal adhesion properties without the need for prior application of an undercoat such as a primer to a cylindrical article, and a tube with extremely good surface precision. An object of the present invention is to provide a method for manufacturing a cylindrical article coated with a fluororesin tube.

(Means for Solving the Problems) In order to achieve the above objects, the present invention firstly forms a resin film containing a heat-resistant resin as a main component on the inner surface of a fluororesin tube having heat-fusible properties. We adopted a configuration in which

Second, as a means for producing a tube-coated cylindrical article, a step of forming a resin film containing a heat-resistant resin as a main component on the inner surface of a fluororesin tube having heat-sealing properties;
A configuration is adopted that includes a step of covering the formed tube on a cylindrical article, and a step of fusing the formed tube to the cylindrical article.

(Example) The means to solve the problem will be explained in detail below.

The fluororesin tube according to the present invention is a cylindrical body formed in a tube shape from a fluororesin,
Further, the heat-shrinkable fluororesin tube is the above-mentioned tube with heat-shrinkability added thereto.

Such heat-shrinkable fluororesin tubes are usually made into a tube shape by film-forming, stretching, etc. of fluororesin. warm to a lower temperature,
Although it can be manufactured by applying internal pressure to the tube and expanding it in the radial direction and, if necessary, in the axial direction, it can be stretched and manufactured. However, the heat-shrinkable tube used in the present invention is limited to the method described above. In short, any material that shrinks when heated is sufficient.

Of course, depending on the manufacturing method, it is also possible to provide a heat-shrinkable tube that has some expansion in one direction and heat-shrinks in the other direction, and these are also included in the scope of heat-shrinkable tubes in the present invention. At this time, the heat shrinkage rate may be set as appropriate and there is no particular restriction, but it is usually 30
Examples include those that shrink in the radial direction by 0 to 25%, preferably about 5 to 15%, and in the axial direction by 25% or less, preferably about 0 to 5% at 0°C.

The fluororesin that is the raw material for the tube used in the present invention is not particularly limited, and its melt viscosity at a molding temperature of 1111 is also preferably lXl0' to l
Examples include those of Those that are capable of thermofluidity are more preferred.

As such a preferable fluororesin, a copolymer of tetrafluoroethylene and a fluorinated ethylenically unsaturated compound can be exemplified, for example, as shown by the following formula, fluoro(alkylethylene): X'(CF*)ncX"=cX'X'Fluoro(oxyalkylethylene)2X'(CF z
) no CX"=CX'X' and fluoro(vinyl polyether): CF.

X'(CFz)no(CFCFtO)mcX"=cX3
A copolymer of a fluorinated ethylenically unsaturated compound and tetrafluoroethylene such as and ethylene/tetrafluoroethylene copolymer (a small amount of a third component may be copolymerized if necessary). Some of these copolymers are Teflon FEP,
It is commercially available as PFA (both are trade names of fluororesins manufactured by Mitsui DuPont Fluorochemical Co., Ltd. and DuPont Company).

Among these tetrafluoroethylene copolymers, those with relatively high melt viscosities, particularly those with specific melt viscosities of 5X10' to 1X10' voids, have high tear strength and are advantageous in the manufacture of tubes and in the use of fused articles. be. Copolymers with a specific melt viscosity exceeding the above range tend to lack thermal fluidity, which may be disadvantageous in tube forming, and they tend to lack adhesive properties to metals, etc., making it difficult to manufacture coating films. However, it can be used depending on the purpose, and the specific melt viscosity is not particularly limited.

The tube according to the present invention may or may not contain a filler, but the addition of the filler does not significantly impair the formability and strength of the raw material composition of the tube and the strength of the fused film. In some cases, it may be preferable to add an appropriate filler such as carbon black or graphite for the purpose of improving the properties of the fusion layer, such as wear resistance, creep resistance, thermal conductivity, or electrical conductivity.

The present invention is achieved by forming a resin film mainly composed of a heat-resistant resin on the inner surface of the fluorine-based tube as described above, and the resin film is formed by coating a liquid material mainly composed of a heat-resistant resin on the inner surface of the fluorine-based tube. The resin film may be coated and formed by passing it through the tube or filling it into the tube, or it may be coated and formed on the inner surface of the tube with a scraper or the like, and there is no particular restriction on the method of formation. species or two
Although it is desirable that the resin is made of only one or more heat-resistant resins, other components may be mixed as appropriate, if necessary.

Normally, to form such a resin film, heat-resistant resin or its precursor is dissolved in an organic solvent, etc., applied as a liquid to the inner surface of the tube, dried, and heat-treated if necessary. Any other conceivable method can be applied.

When using a heat-resistant resin or its precursor dissolved in an organic solvent, examples of the organic solvent include dimethylformamide, dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide, dioxolane, β-butyrolactone, cyclopentanone, isophorone, propylene carbonate, Examples include a cyclohexanone/acetone mixture, a cyclohexanone/dioxane/methyl ethyl ketone mixture, and the resin concentration thereof is 0.1 to 20% by weight, preferably 0.5 to 5% by weight.
I can give an example of the degree. There is no particular limit to the resin concentration, but when forming a resin film by filling and passing a resin liquid into the tube described above, the resin concentration as described above is desirable (of course, it may be used even if it exceeds this range). ), at this level of concentration, the resin solution has an appropriate viscosity and tends to be easily applied uniformly to the inner surface of the tube.

Heat-resistant resins include polypalpanic acid, polyimide resin, polyphenylene sulfide, polyarylate, polysulfide, polyaryl sulfone, polysulfone, polyether sulfone, polyether ether ketone,
Examples include synthetic resins such as polyphenylene ether, among which polypalpanic acid resins and polyimide resins are preferred.

Here, a specific example of forming a resin film inside the tube described above will be described.

First, the tube is cut to an appropriate size, and if necessary, the inner surface is etched, degreased, and cleaned.

After that, the inside of the tube is filled with a specified resin solution,
Methods include tying both ends of the tube and shaking it well, or tying both ends of the tube to a ring-shaped article and filling the tube with a specified resin solution from one end, or allowing the resin solution to pass alternately from both ends. A coating layer may be formed on the inner surface of the tube using a method, followed by drying and, if necessary, heat treatment, etc., to form a resin film of a predetermined thickness.

The above is an example of applying and forming a resin film inside a cut tube, but of course it is also possible to continuously form a resin film on the inner surface of a long tube. Methods such as those shown in FIG. 2 and the like can be considered.

Namely, the tube! This is a method in which the resin solution 2 is filled and confined inside the tube, and then passed through a roll 3 to take it out and drain the liquid.As a result, the resin solution 2 is continuously supplied to the inner surface of the long tube, forming a coating layer. be done. Thereafter, it may be cut and dried if necessary, and heat treated if necessary to form a resin film of a predetermined thickness.

At this time, the resin solution was explained as an example of the resin liquid, but
The resin liquid used for forming the resin film may be a dispersion such as an aqueous dispersion, and is not particularly limited as long as it can form a resin film in any state.

The polyparabanic acid resin preferably used as the heat-resistant resin according to the present invention is a resin obtained by reacting diisocyanate and hydrocyanic acid. 2.4 as diisocyanate
-) lylene diisocyanate, 2.6-) lylene diisocyanate, 4,4°-diphenylmethane diisocyanate, naphthalene-1,5-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 4,4'-methylenebiscyclohexyl Examples include diisocyanates. In this case, when 2.4-)lylene diisocyanate is used, the following reaction formula is shown.

Such polymers are of poor quality, have a high glass transition temperature (for example, about 280 to 400°C), have excellent heat resistance, and are self-extinguishing. Of course, the present invention is not limited to the above description, and includes all those commonly referred to as polyparabanic acid resins. Such a liquid material (processing stock solution) whose main component is polyparabanic acid resin is easy to apply to the inner surface of the tube, enables the formation of a resin film with excellent coating thickness accuracy, and is compatible with fluororesin tubes. It also has the advantage of having excellent adhesive properties, making it extremely advantageous compared to conventional products.

The polyimide resin that is preferably used as the heat-resistant resin according to the present invention is a polymer compound that has an imide bond in the repeating unit in the main chain as the structure of the polymer obtained after heat curing. includes polyimide, polyamideimide, polyetherimide, polyimide sulfone, polyamino bismaleimide, etc. and mixtures thereof.

These polyimide resins can be used alone or in a blend for the brimer treatment agent, and can also be used in a blend with other heat-resistant resins.

The polymer compound will be described in detail below.

(a) The polyimide described above is a synthetic resin having an imide bond in the repeating unit of the main chain, preferably in the formula Ar is a trivalent aromatic group containing at least one aromatic ring, and R is a divalent aromatic group. A polyimide having a repeating unit represented by (indicating an organic group) as a main structural unit is used.

Specifically, (a-1) copolymerizing benzophenone tetracarboxylic dianhydride (BTDA) with two aromatic diisocyanates, namely diphenylmethane-4,4°-diisocyanate and tolylene diisocyanate; It is made by reacting the synthesized (a-3) biphenyltetracarboxylic acid anhydride and metaphenylene diamine, and is manufactured by Ube Industries, Ltd. and is known as "Corbilex R"(Ar' represents a divalent aromatic group). (shown).

(a-2) Consisting of pyrolimetic anhydride and diaminodiphenyl ether, manufactured by DuPont, known under the trade name "Besuvel" (a-4) Biphenyltetracarboxylic anhydride and 4
, 4゛diaminodiphenyl ether, and is manufactured by Ube Industries, Ltd. and is known under the trade name "Corbilex S".

In addition, when diaminodiphenyl ether is used as the diamino compound, the polyimide resin can also be classified as polyetherimide, which will be described later.

(b) The polyamideimide described above is a synthetic resin having an imide bond and an amide bond in the repeating unit of the main chain, and preferably has the following formula (b-2) l-limellitic acid and 4.4゛-diamino A polyamide obtained by the reaction of diphenyl ether and having as a main structural unit a repeating unit represented by (wherein Ar is a trivalent aromatic group containing at least one aromatic ring, and R is a divalent organic group) Imides are used.

To give specific examples, (b-1) A compound obtained by the reaction of trimellinic acid and 4.4°-methylenebisaminobenzene and having a structure such as that manufactured by Amoco and known under the trade name "Torlon". Examples include.

(C) The polyetherimide described above is a synthetic resin having imide bonds and ether bonds in the repeating unit of the main chain, and preferably has the following formula (where Ar is a trivalent compound containing at least one aromatic ring). A polyetherimide having as a main structural unit a repeating unit represented by an aromatic group (R represents a divalent organic group) is used.

Furthermore, polyether sulfide imide in which at least one of the above ether bonds is replaced with a sulfide bond can also be used.

To give specific examples, (c-1) Manufactured by General Electric Company, product name "
Those with structures such as those known as "Ultem".

(c-2) Some of the ether bonds are replaced with sulfide bonds. (d) The polyimide sulfone described above is a synthetic resin having an imide bond and a sulfonyl group in the repeating unit of the main chain, and preferably has the following formula ( A polyimide sulfone having a repeating unit represented by the following formula (wherein Ar is a trivalent aromatic group containing at least one aromatic ring and R is a divalent organic group) as a main structural unit is used.

To give a concrete example, (d-1) Examples include those having the following structure.

Examples include those with structures such as.

(e) The polyamino bismaleimide described above is an addition polymer of bismaleimide and diamine, preferably synthesized from the following formula Zint, and manufactured by Boo [Co. and Technoch Co., Ltd.]
Polyamino bismaleimide, which is jointly developed with E.M.I.E. and is known under the trade name "Conbuimide" (in the formula, R represents a divalent organic group), has a repeating unit as a main structural unit.

Specifically, (e-1) is obtained by an addition reaction between bismaleimide and an aromatic diamine, and is manufactured by Roth-Boulin and is known under the trade name "Kinel" (in the formula, R represents an aromatic group), etc. Examples include those with the structure.

Such a polyimide resin is generally used in the form of a polyimide resin precursor (polyamic acid) represented by the following formula, dissolved in a solvent.

(In the formula, R1 and R't represent -gupi)←c+h (匡)-, etc.).

(e-2) Bismaleimide and aminobenzoic acid hydra precursor are polyamide resins having carboxyl groups, which easily form polyimide bonds by heating and dehydration.

(In the formula, Ar represents a trivalent aromatic group, and R represents a divalent organic group.) In this way, the precursor is dissolved in an organic solvent and used, but the above is just one specific example. It should not be particularly limited.

Further, as described above, the resin film of the present invention can be formed by using a heat-resistant resin as a main component and mixing other components as appropriate, if necessary.

In the present invention, the inner surface of the fluororesin tube may be subjected to an appropriate inner surface treatment if necessary, and then a resin film containing a heat-resistant resin as a main component may be formed thereon. Examples of such inner surface treatment include chemical etching using a dispersion of an alkali metal such as sodium metal, and various other known methods. Of course, such inner surface treatment is used when the fluororesin tube and the resin film whose main component is a heat-resistant resin do not fit easily, and the scope of the present invention is of course also when no inner surface treatment is performed.

Such inner surface treatment may be carried out by any suitable method before forming the resin film, but the chemical etching method using metallic sodium is most suitable for treating the tube in the form of a tube.

In the present invention, there are no particular restrictions on the material that can be thermally fused with the fluororesin tube having a resin layer on its inner surface (material to be fused), but cylindrical articles, especially metallic ones, are preferred. More preferred. Examples of such cylindrical articles include pipes and rolls made of metal, such as aluminum or aluminum alloy, as described above, and are not particularly limited. These cylindrical articles include hollow cylindrical bodies. It also includes cylindrical shapes with no hollow interior, and in this case, the cylindrical shape does not necessarily have to be a cylinder in the strict sense.

If necessary, the surface of such a cylindrical article may be roughened by physical treatment, chemical treatment, etc., before being coated with a tube, so that thermal fusion can be more easily formed. It's easier and more convenient.

(It goes without saying that the present invention can be achieved without such appropriate treatment). Such physical treatment is not particularly limited, but examples include sandblasting, liquid honing, barrel polishing, etc., and is a treatment that roughens the surface of the aluminum cylindrical body by physical action to give it a satin-like or ground-glass appearance. In terms of surface roughness (J 15-B-0601), it is preferably about 3 to 15 microns, more preferably about 5 to 10 microns, but of course there is no particular limit to this value.

A preferred physical treatment is sandblasting, which is exemplified by a method in which sand-like materials such as alumina powder, silica, glass beads, etc. are injected together with compressed air toward the surface of the aluminum cylinder.

At this time, there are no particular restrictions on the type of sand-like material, the amount of agitation, etc., and they may be set appropriately so as to provide a predetermined surface, but usually, those with an average amount of agitation of 100 μm or less tend to be used. The injection pressure may also be set appropriately depending on the purpose. There are no particular restrictions on the chemical treatment mentioned above, but -
Boat fishing can be carried out using various gases, chemicals, etc., and electrochemical treatments such as alumite treatment are also very effective.

Coating a cylindrical article with a tube, such as a heat-shrinkable tube, is accomplished by first inserting the cylindrical article into the tube (or vice versa), and then heat-treating it at a predetermined temperature. It is easier to insert the tube by making it slightly thicker than the diameter of the cylindrical article, and when it is shrinked by heat treatment, it will tightly cover the cylindrical article, but if the tube diameter and the cylindrical article are the same or the former It is convenient to make the tube a little smaller and forcefully insert the cylindrical article because it allows tighter coverage due to the shrinkage stress of the tube during heat treatment. At this time, there are no particular restrictions on the means of heat treatment.
This can be carried out in a heated atmosphere such as a heating furnace or by using a heat gun or the like.

For example, the manufacturing method of the present invention can be accomplished by heat-sealing a tube coated as described above, preferably a heat-shrinkable tube, onto the surface of a cylindrical article.

Heat fusion is achieved by heat treatment at a temperature higher than the melting point of the fluororesin that is the raw material for the tube. A heating furnace is suitable as a means for performing the heat treatment, but there is no particular restriction. Through such heat treatment, the cylindrical article and the tube are firmly heat-fused.

Although it is advantageous to carry out the coating and fusing of the tube continuously by changing the heat treatment temperature conditions in the second step, it is of course possible to carry out the coating and fusing in two steps in a batch manner.

If it is carried out in a process, it may be carried out by continuously raising the temperature from a low temperature to the fusion temperature. In this case, the coating process is completed in the process of gradually increasing the temperature, and the coating process and the fusion process are Although the boundaries are not clear, such cases are naturally included in the present invention. At this time, the temperature conditions during the heat treatment vary depending on the type of fluororesin and are not particularly limited, and in the case of the above-mentioned tetrafluoroethylene copolymer, there are also no particular limitations, but when expressed in ambient temperature, the
An example is about 310 to 400°C during the 0 to 320' C1 fusion process, and when expressed in terms of tube surface temperature, it is 50°C to below the melting point of the resin during the coating process, and above the melting point of the resin during the fusion process. An example is about 400°C. The above description has been made using a heat-shrinkable tube as an example, but the same applies to the case where a non-heat-shrinkable tube is used, and there is no particular restriction.

The use of the fluororesin tube-fused cylindrical article according to the present invention is not particularly limited (it can be used in a wide variety of fields, but it is preferably used as a heat roll in a fixing device in an electronic copying machine or as a heat roll in a laser beam printer). It is used as a heat roll in a fixing device, etc.

In general, electronic copying machines use static electricity to form a toner image on copy paper, which is then passed through rotating rolls (heat roll and pressure roll) that are pressed against each other to heat and melt the toner. Fix it on the copy paper. In such a fixing method, it is necessary to prevent a phenomenon called "offset" in which molten toner adheres to a heat roll and a portion of the attached image is newly attached to copy paper. Therefore, the surface of the heat roll is coated with a fluororesin to prevent toner from adhering to it, and from this point of view as well, the cylindrical article according to the present invention is particularly useful.

The above description is merely a description of preferred embodiments of the present invention, and it goes without saying that the present invention is not limited to these descriptions.

Next, more specific embodiments of the present invention will be described.

(Example 1) An average particle size of 60 nm was applied to an aluminum pipe with a diameter of 20+ nm.
μ alumina (AIZO3) powder at 5.5kg/crl
Sandblasting was carried out by spraying at a pressure of 100.degree. C. to obtain a pipe having a satin-like surface with a surface roughness of 8 .mu.m.

On the other hand, in a heat-shrinkable tube made of tetrafluoroethylene/perfluorovinylether copolymer (melting point 308°C) with a heat shrinkage rate of 7% in the radial direction and 2% in the axial direction at 300°C, ethylene of sodium naphthalene was placed. The glycol/dimethyl ether suspension is confined and subjected to chemical etching treatment, and then the first
As shown in the figure or Fig. 2, the resin solution 2 dissolved in dimethylformamide so as to have a polyparabanic acid resin concentration of 2.5% by weight is confined and the tube 1 is continuously moved, and then the resin solution 2 of Fig. 2 is enclosed. was cut into a predetermined size and dried with hot air at 150°C to obtain a heat-shrinkable tube 1 made of tetrafluoroethylene/perfluorovinyl ether copolymer with a polyparabanic acid resin film formed on the inner surface.

Next, the heat-shrinkable tube was inserted into the pipe having the satin-like surface. (The tube has some elasticity, so it is easily inserted.) Next, it is left in an oven, the temperature is gradually raised, and heat treated in an atmosphere of 310°C (the surface temperature of the tube is 307°0) for 20 minutes. Due to the shrinkage stress of the tube, the tube was tightly coated with the first layer, and the temperature was further raised to 350° C. for 40 minutes to perform a fusion treatment.

The aluminum vibrator thus obtained has a surface accuracy of Rg =
The thickness was 1.2μ, which was extremely good, and there were very few thickness irregularities. When such a pipe was commercialized as a heating roll and used as a heat roll (fixing roll) for an electronic copying machine, extremely good performance was ensured. In addition, in such a heat roll, the tube was firmly fused through the resin layer, and when an attempt was made to forcefully peel it off using a screwdriver, the tube surface was damaged.

(Example 2) An aluminum pipe was obtained in the same manner as in Example 1 except that a liquid product in which polyamideimide resin was dissolved in dimethylformamide was used instead of polyparabanic acid resin. Similar to Example 1, this pipe also has a tube that is firmly fused through the resin layer and has a surface area R2=1.2.
The thickness was very good, and there were very few thickness irregularities.

(Example 3) An aluminum pipe was obtained in the same manner as in Example 1 except that the sandblasting treatment was not performed. In this pipe, as in Example 1, the tube was firmly fused through the resin layer, but the fusion strength seemed to be slightly inferior to that in Example 1.

(Effects of the Invention) Since the present invention is formed by forming a resin film containing a heat-resistant resin as a main component on the inner surface of a fluororesin tube having heat-sealing properties, it has extremely excellent surface precision, such as It is suitable for use by being fused to articles to be fused (cylindrical articles, etc.).

Furthermore, the present invention includes a step of forming a resin film containing a heat-resistant resin as a main component on the inner surface of a fluororesin tube having heat-adhesive properties, and a step of coating the formed tube on a cylindrical article. and a step of fusing the formed tube to the cylindrical article, the method for manufacturing a coated cylindrical article does not require prior coating of the cylindrical article with a primer such as a primer. It has now become possible to provide a fluororesin tube-coated cylindrical article with extremely good surface precision, which is provided with a heat-resistant resin film that has sufficient heat-sealing properties even when heated.

[Brief explanation of the drawing]

FIGS. 1 and 2 are cross-sectional views showing an example of a method for continuously forming a resin film on the inner surface of a tube. 1...Tube, 2...Resin solution, 3...Roll.

Claims (7)

[Claims] (1) A tube characterized by forming a resin film containing a heat-resistant resin as a main component on the inner surface of a tube made of a fluororesin having heat-fusion properties. (2) The tube according to claim (1), wherein the fluororesin tube has heat shrinkability. (3) The tube according to claim 1 or 2, wherein the heat-resistant resin is a polyparabanic acid resin and/or a polyimide resin. (4) a step of forming a resin film containing a heat-resistant resin as a main component on the inner surface of a fluororesin tube having heat-sealing properties; a step of coating the formed tube on a cylindrical article; A method for manufacturing a tube-covered cylindrical article, comprising the step of fusing the formed tube to the cylindrical article. (5) The method for manufacturing a tube-covered cylindrical article according to (4), wherein the fluororesin tube has heat shrinkability. (6) The method for producing a tube-covered cylindrical article according to claim (4) or (5), wherein the heat-resistant resin is a polyparabanic acid resin and/or a polyimide resin. (7) The method for producing a tube-covered cylindrical article according to claim (4), wherein the inner surface of the fluororesin tube is treated in advance before forming the resin film.