JPH07115363B2 - Method for manufacturing tubular products - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a tubular article, and more particularly to a method for producing a tubular article having a smooth outer surface.

<Prior Art> Tubular materials made of synthetic resin are used for various purposes.
One of them is the use as a seamless belt.

Usually, the belt that transmits the driving force generated by the rotation of the motor, etc., or conveys the article is connected by abutting the ends of a sheet-shaped or strip-shaped molded product, or stacking them and bonding them with an adhesive or the like. However, since the mechanical strength of the connecting portion is poor and the connecting portion has a step difference, it cannot be said that the adhesion with the pulley to be attached is sufficient, and it is difficult to obtain smooth rotation.

On the other hand, since the belt manufactured from the tubular material is seamless, the conventional product is being replaced by a seamless belt.

In order to produce a tubular product for obtaining such a seamless belt, JP-A-60-166424 discloses that a polyamic acid solution is applied to the inner peripheral surface of a cylinder, the solvent is removed by heating, and the polyamic acid solution is used. A method for obtaining a polyimide tubular product by converting imide into imide has been proposed.

<Problems to be Solved by the Invention> However, the tubular article obtained by this method solves the above-mentioned drawbacks, but is produced in a state where the outer surface of the tubular article is in contact with the inner peripheral surface of the cylinder. Therefore, the smoothness (surface roughness) of the outer surface of the tubular object depends on the smoothness of the inner peripheral surface of the cylinder, and scratches and the like may be transferred as they are, causing problems in terms of mechanical strength. Is.

Further, when a belt lacking in smoothness on the outer surface is used as, for example, a carrier belt for supporting a photoconductor belt used in an electrophotographic copying machine, an image due to pattern exposure on the photoconductive layer and the photoconductive layer of the photoconductor belt is formed. There is also a problem that it cannot be obtained accurately and clear copying cannot be performed.

<Means for Solving Problems> An object of the present invention is to obtain a tubular article having an outer surface smoothness which cannot be obtained by the tubular article obtained by the conventional method.

That is, the method for producing a tubular product of the present invention is a synthetic resin tubular product obtained by applying a synthetic resin solution to the inner peripheral surface of a cylinder and then partially semi-drying the solvent in the solution, and peeling the synthetic resin tubular product from the cylinder to obtain a core. It is characterized in that the residual solvent is removed by inserting a material and then heating.

In the present invention, first, the inner diameter is usually about 1 to 50 cm metal,
A synthetic resin solution is applied to the inner peripheral surface of a heat-resistant cylinder made of glass, a fluororesin or the like (if desired, a mold release treatment is applied to the inner peripheral surface by applying a solution of a silicone resin, a fluororesin or the like).

The application of the synthetic resin solution to the inner peripheral surface of the cylinder can be performed by a conventionally known method, for example, a depping method of immersing the cylinder in the synthetic resin solution and pulling it up, or a synthetic resin solution near one end of the cylinder. It can be carried out by a method of supplying and then unrolling with a scraper or the like.

The synthetic resin solution applied to the inner peripheral surface of the cylinder can be arbitrarily selected according to the intended use of the tubular product, and examples thereof include solutions of polyimide, polyamic acid, polyamideimide, polybenzimidazole and the like.
Among these synthetic resins, it is preferable to use polyimide as a super engineering plastic excellent in heat resistance, mechanical properties, chemical properties and the like and polyamic acid as a precursor thereof.

The polyimide and polyamic acid solution can be obtained, for example, by reacting a substantially equimolar mixture of an aromatic tetracarboxylic dianhydride (or a derivative thereof) and an aromatic diamine in an organic polar solvent.

Specific examples of such aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4 ′-
Biphenyl tetracarboxylic dianhydride, 2,3,3 ', 4'-
Biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetra Examples thereof include carboxylic acid dianhydride, 2,2'-bis (3,4-dicarboxyphenyl) propane dianhydride and bis (3,4-dicarboxyphenyl) sulfone dianhydride.

On the other hand, specific examples of the aromatic diamine include 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 3,3′-diaminodiphenylmethane, paraphenylenediamine, metaphenylenediamine, benzidine, 3,3′- Dimethoxybenzidine, 4,4′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl sulfide, 4,4′-diaminodiphenylpropane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, etc. Can be mentioned.

Furthermore, specific examples of the organic polar solvent include N-methyl-
2-pyrrolidone, N, N-dimethylacetamide, dimethylformamide, dimethylsulfoxide, hexamethylenephosphortriamide and the like can be mentioned. These organic polar solvents may be mixed with phenols such as cresol, phenol and xylenol, and hydrocarbons such as hexane, benzene and toluene.

The monomer concentration in the solvent when the aromatic tetracarboxylic dianhydride and the aromatic diamine are reacted in the solvent to obtain a polyamic acid solution can be set according to various conditions, but usually 5 to 30 % By weight, preferably 10 to 25% by weight, usually less than 80 ° C., preferably about 1 to 50 ° C.
Allow to react for ~ 10 hours.

The polyamic acid solution obtained as described above is obtained in a state where the solution viscosity increases with the progress of the reaction, but in the present invention, the intrinsic viscosity is 0.5 or more (30 ° C., N-methyl-2
It is preferred to obtain a polyamic acid solution of (in pyrrolidone). By using a polyamic acid solution having an intrinsic viscosity of 0.5 or more, the obtained tubular product has particularly excellent heat deterioration resistance.

In applying the synthetic resin solution to the inner peripheral surface of the cylinder in the production method of the present invention, the viscosity of the solution is the application thickness,
Although it can be appropriately set according to the cylinder inner diameter, coating temperature, etc., it is usually about 10 to 10,000 poise (temperature during coating process, measured value by B-type viscometer), and synthetic resin concentration in the solution is 5 to 5. It is set to 30% by weight, preferably 10 to 20% by weight.

In the present invention, after applying a synthetic resin solution to the inner peripheral surface of the cylinder, a part of the solvent is removed by semi-drying and peeled from the cylinder to obtain a synthetic resin tubular product containing residual solvent, but preferably semi-drying The solvent content at that time is adjusted to be 5 to 50% by weight. If the solvent content after drying is less than 5% by weight, the fluidity of the outer surface of the synthetic resin tubular product tends to be lost, and the outer surface of the tubular product obtained by inserting and heating the core material in the subsequent process is smooth. There are cases where the sex is not sufficient. On the other hand, if it exceeds 50% by weight, the fluidity of the synthetic resin tubular product may become too large, and it may be difficult to finally obtain a tubular product having a uniform thickness.

Since the synthetic resin tubular product containing the residual solvent obtained as described above has an appropriate fluidity while maintaining the shape, after the core material is inserted, the residual solvent is removed by heating to remove the external surface. Becomes smooth.

As the core material to be inserted, metals such as copper, aluminum, iron, and brass, heat-resistant plastics such as tetrafluoroethylene, glass, etc. can be used without particular limitation, and their shapes are cylindrical, cylindrical, square. A columnar shape or the like can be used. Of these shapes, when the tubular product obtained in the present invention is used as a seamless belt, it is preferable to use a columnar (rod-shaped) or cylindrical (pipe-shaped or tube-shaped) core material. Further, when obtaining a tubular article for a belt, various protrusions on the outer surface of the core material, for example, a square shape, a circular shape,
It is preferable to use a product in which the outer surface provided with a protrusion such as a linear shape is processed into an uneven shape. When a tubular product with a core material with an uneven outer surface inserted is manufactured, the inner wall surface of the resulting tubular product becomes uneven, and it fits well when attached as a belt to a pulley, and a slip phenomenon occurs during drive rotation. Instead, the driving force can be reliably transmitted.

Further, if the synthetic resin forming the tubular product is hard, the flexibility of the tubular product becomes poor, and in particular, it becomes impossible to bend by making the radius of curvature small. Therefore, in applications requiring such flexibility. In order to use a tubular product, it is preferable that the core material has a corrugated longitudinal section. For example, as the core material, a metal wire or metal strip wound around the core material having the above-mentioned cylindrical shape in a spiral shape can be used.

In the present invention, as described above, the target tubular material having a smooth outer surface can be obtained by inserting the core material, removing the residual solvent by heating, and then removing the core material. The outer surface of the obtained tubular product is extremely smooth, and it is possible to obtain a product having a surface roughness of 0.05 μm or less using a surface roughness meter.

<Effects of the Invention> As described above, the method for producing a tubular article of the present invention removes a part of the solvent of the synthetic resin solution applied to the inner peripheral surface of the cylinder by drying, and then once peels it off and inserts the core material. Since the residual solvent is removed by the residual solvent, the outer surface of the obtained tubular product does not depend on the smoothness of the inner peripheral surface of the cylinder and becomes a smooth surface with extremely small surface roughness.

In addition, the belt made from the obtained tubular material is not only seamless, but also has excellent mechanical strength without scratches on the surface, especially the belt from a polyimide tubular material using polyimide as a synthetic resin. When manufactured, it becomes a belt having excellent heat resistance and mechanical properties, and is useful as a driving force transmission belt, a conveyance belt, and a carrier belt for electrophotographic copying.

Further, when a core material having an uneven outer surface is used as the core material used in the production method of the present invention, the inner wall surface of the obtained tubular product becomes uneven, and when used as a belt, the inner wall surface becomes uneven. The slip phenomenon is improved, and the force such as the driving force can be reliably transmitted. In addition, by increasing the depth of the irregularities on the outer surface of the core material and using a core material having a corrugated longitudinal cross section, the tubular product obtained also has a corrugated longitudinal cross section, which is excellent in flexibility. Obtainable.

<Example> The present invention will be described in more detail with reference to the following examples, but it goes without saying that various modifications and applications may be made without departing from the technical idea of the present invention.

Example 1 An equimolar mixture of pyromellitic dianhydride and 4,4-diaminodiphenyl ether was reacted in N-methyl-2-pyrrolidone (monomer concentration 20% by weight) at a temperature of 10 ° C. for 10 hours to obtain a solution viscosity of 25,000. A polyamic acid solution having a poise (50 ° C, B-type viscometer) and an intrinsic viscosity of 2.4 (30 ° C, Ubbelohde-type viscometer) was obtained.

To 100 parts by weight of this solution, 33 parts by weight of N-methyl-2-pyrrolidone was added and diluted, and the mixture was heated to 50 ° C. to prepare a solution having a viscosity of 900 poise.

Next, immerse an iron pipe with an inner diameter of 120 mm, a wall thickness of 10 mm, and a length of 50 cm in this solution (the inner peripheral surface of which has been surface-finished to 1S, which has been coated with silicone resin and baked to release it). Then, the polyamic acid solution was filled and pulled up.

Then, a bullet-shaped body having an outer diameter of 119.0 mm was run in the iron pipe at a speed of 20 mm / min to apply the polyamic acid solution to the inner peripheral surface of the iron pipe with a uniform thickness.

Then, this is heated at 130 ℃ for 60 minutes to reduce the solvent content to 40
The polyamic acid tubing formed in the iron pipe was peeled off and pulled out by cooling to room temperature.

Next, an aluminum pipe having an outer diameter of 118.7 mm and a length of 50 cm was inserted into the polyamic acid tubular product, placed in a hot air dryer, heated from 200 ° C to 300 ° C over 1 hour, and then heated at 300 ° C. After heating for 30 minutes, the residual solvent was removed and the imide was converted, and the mixture was cooled to room temperature.

After cooling, by pulling out the core material, the inner diameter is 119.5 mm,
A polyimide tubular product having a wall thickness of 75 μm, a length of 40 cm and an outer surface roughness of 0.01 μm was obtained.

The photosensitive belt for electrophotographic copying prepared from the obtained tubular product was able to obtain a clear copy image with less noise compared with the conventional product.

Comparative Example 1 In Example 1, the polyamic acid tubular product was not peeled off, and the heating residual solvent was removed and the imide conversion was performed in a state of being coated on the inner peripheral surface of the iron pipe to obtain a polyimide tubular product.

In this case, on the outer surface of the obtained tubular product, the surface roughness of the inner peripheral surface of the iron pipe is transferred as it is to 0.2 μm, and when used as a photosensitive belt for electrophotographic copying, there are many noises and the definition is poor. I couldn't get it.

Example 2 An iron pipe having an inner diameter of 60 mm, a wall thickness of 5 mm and a length of 50 cm was placed in a solution of 900 poise of the solution clay obtained in Example 1 (the inner peripheral surface treatment was the same as that of the iron pipe used in Example 1). Was dipped, filled with a polyamic acid solution and pulled up.

Next, a bullet-shaped body having an outer diameter of 59.2 mm was run inside the iron pipe at a speed of 20 mm / min to apply the polyamic acid solution to the inner peripheral surface of the iron pipe with a uniform thickness.

Then, it is heated at 125 ℃ for 60 minutes to reduce the solvent content to 40
The polyamic acid tubing formed in the iron pipe was peeled off and pulled out by cooling to room temperature.

Next, a core material (see FIG. 1) having an outer diameter of 59.5 mm and a length of 50 cm and a groove of 1 mm in pitch and 0.7 mm in depth on the outer peripheral wall of the rod was made into the above polyamic acid tubular material. It was inserted and heated under the same conditions as in Example 1 to remove the residual solvent and convert the imide to obtain a polyimide tubular product.

The obtained tubular product has an inner diameter of 59.5 mm, a wall thickness of 70 μm, and a length of 48 cm, and linear projections with a pitch of 1 mm are formed in the lengthwise direction on the inner wall surface, and the outer peripheral surface has a surface roughness of 0.01 μm. The surface was extremely smooth.

The obtained tubular product was cut into a belt-shaped tubular product by cutting it into a width of 6 mm, the belt was attached so that a tension of 1 kg was applied between pulleys having a diameter of 5 mm, and the belt was driven and rotated at 3000 rpm.

As a result, the belt did not break even when the number of driving times reached 1 × 10 ⁷ , and no slip phenomenon between the pulleys was observed. Further, the belt did not meander.

Incidentally, a polyimide tubular article having no linear protrusions on its inner wall surface was produced in the same manner as in Example 2 except that the core material used in Example 2 above had no groove, and the belt was used in Example 2 above. When the belt was driven and rotated under the same conditions as in 1., the belt was not broken, but a slip phenomenon started to be slightly exhibited after the number of times of driving was about 1 × 10 ³ times.

Example 3 An equimolar mixture of pyromellitic dianhydride and 4,4-diaminodiphenyl ether was reacted in N-methyl-2-pyrrolidone (monomer concentration 20% by weight) at a temperature of 10 ° C. for 5 hours to obtain a solution viscosity. A polyamic acid solution having a viscosity of 20,000 poise (50 ° C., B type viscometer) and an intrinsic viscosity of 2.8 (30 ° C., Ubbelohde viscometer) was obtained. The solution was heated at 50 ° C. for 24 hours to adjust the solution viscosity to 3,000 poise.

Next, an inner diameter of 50 mm, a wall thickness of 10 mm, and a stainless steel cylinder having a length of 50 cm were immersed in this solution, filled with a polyamic acid solution and pulled up, and then a bullet-shaped body having an outer diameter of 48.5 mm was run in the cylinder. Then, the polyamic acid solution was uniformly applied to the inner peripheral surface of the cylinder.

Then, by heating this at 150 ° C. for 60 minutes to remove the contained solvent so that the solvent content becomes 24% by weight, the system is cooled to room temperature, and the polyamic acid tubular product formed in the cylinder is peeled off and pulled out. It was

Next, insert a brass tube (outer diameter 49.5 mm, see Fig. 2) in which 2 mmφ copper wire is spirally wound at 5 mm intervals into the above polyamic acid tubular product and heat it to 400 ° C to remove residual solvent. Was removed and the imide was converted, and the mixture was cooled to room temperature.

After cooling, the copper wire wound around the core material was pulled out while being plastically deformed, and then the core material was pulled out to obtain a polyimide tubular product having a corrugated longitudinal section.

Since the obtained tubular product is molded into a corrugated pipe with a core material, it has excellent flexibility, and its outer surface also has a surface roughness of 0.02.
It had a smoothness of μm, no scratches on the surface, and excellent mechanical strength. Also, in terms of heat resistance, there was no change in shape at 300 ° C, which was good.

[Brief description of drawings]

FIG. 1 shows Example 2 of the method for producing a tubular article according to the present invention.
2 is a side view of the core material used in Example 3, and FIG. 2 is a side view of the core material used in Example 3. 1 ... Core material, 2 ... Groove, 3 ... Copper wire

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 60-203427 (JP, A) JP 60-190337 (JP, A) JP 60-166424 (JP, A)

Claims (4)

[Claims] 1. A synthetic resin tubular product obtained by applying a synthetic resin solution to the inner peripheral surface of a cylinder and partially semi-drying the solvent in the solution, peeling the tubular product from the cylinder, inserting a core material, and then heating. A method for producing a tubular product, which comprises removing residual solvent by 2. The method for producing a tubular article according to claim 1, wherein the synthetic resin solution is a polyamic acid solution. 3. The method for producing a tubular article according to claim 1, wherein the solvent content in semi-drying is 5 to 50% by weight. 4. The method for producing a tubular article according to claim 1, wherein at least an inner wall surface of the tubular article obtained by providing an uneven shape on the outer surface of the core material is provided with an irregular shape.