JP2001001397A - Stretching roll for manufacturing film and manufacture of polyester film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To scarcely damage a stretching roll in the case of mounting or removing the roll in a manufacturing line and to provide good durability directed to manufacture a smooth product without damage by making a surface layer of a metal layer containing a non-adhesive resin and setting a hardness of the metal layer to a specific value or more. SOLUTION: The stretching roll is formed with predetermined surface properties by coating a surface of a cylindrical core with an alloy powder of a tungsten carbide- nichrome or the like by a thermal spraying method such as a pressure reducing plasma spraying machine or the like, forming a superhard alloy film having a high surface hardness, then dissolving a predetermined non-adhesive resin to impregnate it with its solution, and then polishing the roll to be finished. As the resin, a water repellent resin having non-adhesivity no functional group such as an epoxy resin or the like in a molecule such as a fluorine-containing polymer such as a polytetrafluoroethylene or the like or a silicone resin or the like is used. The hardness HV of the surface metal layer of the roll is 900 or more. Thus, good durability is provided, and a smooth product having no damage even by repeatedly using for a long period can be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film-stretching roll utilizing a difference in peripheral speed between rolls, and more particularly to a film-stretching roll suitable for producing a smooth polyester film having good surface properties.

[0002]

2. Description of the Related Art Consumer digital video tapes put into practical use in 1995 are provided with a metal magnetic thin film of Co on a base film having a thickness of 6 to 7 .mu.m by vacuum evaporation and coating the surface with a diamond-like carbon film. Become
In the case of a camera-integrated video using a DV mini-cassette, the basic specification (SD specification) has a recording time of one hour.

This digital video cassette (DVC) tape is the world's first digital video cassette tape for home use. A large body of information can be recorded despite its small body. B. Since the signal does not deteriorate, the image quality and sound quality do not deteriorate even after many years, c. Because it is not disturbed by noise,
Enjoy high image quality and high sound quality, d. It has such advantages that the image does not deteriorate even after repeated dubbing, and is highly evaluated in the market.

[0004] Since the magnetic layer of the DVC tape is very thin and the surface morphology of the polyester base film becomes the surface morphology of the tape as it is, the surface of the polyester base film for the DVC tape is increasingly required to be free from scratches. It has become.

[0005] Usually, a polyester film is produced using a stretching roll utilizing a peripheral speed difference between the rolls.
As a film stretching roll suitable for producing a smooth polyester film, a roll using rubber such as silicone for the surface layer, a metal roll such as chrome plating on the surface layer, a resin component on the surface, any one of metal and ceramic, Or a roll coated such that a combination of two or more thereof and Teflon are dispersed (Japanese Patent Application Laid-Open No. 60-78724).
However, in order to produce a polyester base film such as a polyester base film for a DVC tape, which is smooth and has few scratches on the surface, a roll using a rubber such as silicone as a surface layer is required to be stretched and stretched over time. The rubber is scraped and defects such as streaks are formed on the roll surface.As a result, the film stretched on the roll tends to have a large amount of scratches. The film sticks to the surface of the roll, and uneven peeling tends to occur, and surface defects such as sticking marks tend to occur, and any one of a resin component, a metal, and a ceramic, or a combination of two or more of these are used on the surface. In the case of a roll coated so that the material and Teflon are dispersed, the surface of the adhesive traces caused by the film sticking to the roll surface, which has become hot during stretching, Although disadvantage does not occur, because the roll surface of rough, the stretched surface of the film is likely to enter a large amount scratches, polyester base film for a DVC tape could not be produced. In order to eliminate these defects, the roll surface layer is made of a metal containing fine particles of fluorine-containing polymer, and the surface roughness Ry of the surface layer is
A surface scratch having a value of 0.3 μm to 1.0 μm and a height or depth, or a sum of height and depth of 1.0 μm or more is 40/100 cm ² or less, for film production. Stretching rolls have been made to produce polyester base films for DVC tapes (Japanese Unexamined Patent Publication No.
No. 76571).

[0006] The stretching roll disclosed in Japanese Patent Application Laid-Open No. H10-76571 has made it possible to produce a polyester base film such as a polyester base film for DVC tape, which has a smooth surface with few scratches. When the jig or other object touches the surface of the stretch roll when care is taken carelessly when attaching or removing it to the stretch roll, the surface of the stretch roll tends to be scratched, which may damage the polyester film being manufactured. In addition, when the surface of the stretching roll is soiled, when the roll surface is wiped and cleaned with a clean cloth, the surface of the stretching roll tends to be scratched, and therefore, the polyester film being manufactured tends to be scratched. I knew it.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and is useful for producing a smooth and scratch-free polyester film which is hardly damaged when being attached to or detached from a production line. An object of the present invention is to provide a stretch roll having good properties.

[0008]

According to the present invention, the surface layer comprises a metal layer containing a non-adhesive resin, and the hardness of the metal layer is H.
A stretching roll for producing a film, wherein V is 900 or more, and a method for producing a polyester film using the same.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The roll for stretching a film in the present invention is a roll for stretching a film between heated rolls having different peripheral speeds, and is a cylindrical roll that can be driven and rotated.

[0010] The roll surface is composed of a metal layer containing a non-adhesive resin. As the non-adhesive resin, non-adhesive, does not have a functional group such as epoxy resin in the molecule, a water-repellent resin is used, specifically, polytetrafluoroethylene, perfluoroalkoxy resin, Ethylene-tetrafluoroethylene resin, polyvinylidene fluoride, fluorine-containing polymer such as fluororubber, polydimethylsiloxane, polyhydrogenpolysiloxane, polymethylphenylsiloxane, fluoroalkyl-modified silicone,
Examples include silicone resins such as amide-modified silicone and epoxy-modified silicone, and mixtures thereof.

The hardness (HV) of the metal layer on the surface of the stretching roll is:
It is 900 or more, preferably 1000 to 1600, more preferably 1000 to 1500. By using a cemented carbide as the metal, a hardness of 900 or more in HV is easily achieved.

When the HV is 900 or more, the abrasion resistance is excellent, and when the stretch roll is attached to or detached from a film forming line, careless handling of the stretch roll may cause an object such as a jig to touch the stretch roll surface. However, it is possible to prevent the surface of the stretching roll from being damaged. In addition, when the surface of the stretching roll becomes dirty, even if the roll surface is wiped and cleaned with a clean cloth, the surface of the stretching roll is prevented from being damaged. If the HV exceeds 1600, the roll surface becomes too hard, and it becomes difficult to control the surface roughness Ry value.

The thickness of the metal layer is preferably 10 to 900.
μm, more preferably 50 to 500 μm. If the thickness is less than 10 μm, the wear resistance is undesirably reduced. If the thickness exceeds 900 μm, the metal layer is easily broken, which is not preferable.

When the non-adhesive resin is contained in the metal layer, sticking between the roll surface and the film, which has become high during stretching, is prevented.

[0015] The content of the non-adhesive resin is preferably 0.1 to 0.5.
The content is desirably 1 to 30% by weight, more preferably 0.3 to 20% by weight. If the content is less than 0.1% by weight, adhesion between the roll surface and the film, which has been heated to a high temperature during stretching, is not preferred. If the content is more than 30% by weight, the non-adhesive resin tends to fall off the alloy layer, which is not preferable.

The surface roughness Ry of the roll surface layer is preferably 0.3 μm to 1.0 μm, more preferably 0.5 μm.
m to 1.0 μm is desirable.

If the Ry value is less than 0.3 μm, the surface of the stretching roll becomes a super mirror surface, the film does not slide on the roll surface, and it is difficult to stretch the film.
If the Ry value is greater than 1.0 μm, the roughness of the surface of the stretching roll is transferred to the stretched film, and the stretched film has a undulating undulation, which is not preferable.

[0018] The roll surface layer, the height or depth or height and depth of the sum 1.0μm or more surface flaws, is 40/100 cm ² or less, nothing is preferable if possible.

If the number of surface scratches exceeds 40/100 cm ² , a large amount of scratches having a height of about 0.25 μm or more tend to enter the stretched film, which is not preferable. The closer the surface scratches are to zero, the more difficult it is for the stretched film to be damaged, which is preferable.

The stretching roll for the present film is a polyester film for home digital video (DVC) tape, which has a very small number of scratches, especially a polyethylene terephthalate and polyethylene-2,6-naphthalate film. Utilized and suitable for use as a draw roll for manufacturing. The term “polyethylene terephthalate” or “polyethylene-2,6-naphthalate” as used herein means that 80% or more of its constituent components are ethylene terephthalate or ethylene naphthalate.
Examples of the polyester copolymer component other than ethylene terephthalate and ethylene naphthalate include diol components such as diethylene glycol, propylene glycol, neopentyl glycol, polyethylene glycol, p-xylylene glycol, and 1,4-cyclohexanedimethanol, adipic acid, Examples include dicarboxylic acid components such as sebacic acid, phthalic acid, isophthalic acid, and 5-sodium sulfoisophthalic acid, polyfunctional dicarboxylic acid components such as trimellitic acid and pyromellitic acid, and p-oxyethoxybenzoic acid.

Further, the above polyester does not exceed 5% by weight of at least one of an alkali metal salt derivative of sulfonic acid which is non-reactive with the polyester and a polyalkylene glycol which is substantially insoluble in the polyester. You may mix to the extent. Also used as stretching rolls for manufacturing films that require smooth and very few scratches, such as polyethylene terephthalate and polyethylene-2,6-naphthalate films for optical applications, utilizing the difference in peripheral speed of the rolls Suitable to do.

Next, the method for producing the stretching roll of the present invention will be described, but the present invention is not limited thereto.

The stretching roll of the present invention has, for example, a structure in which a tungsten carbide-nichrome (WC-
NiCr), tungsten carbide-cobalt (WC
-Co), chromium carbide-cobalt (CrC-C)
o), etc., to form a cemented carbide film having a high surface hardness by applying a spraying method using a reduced pressure plasma spraying device, an aeroplasma spraying device, an arc spraying device, a frame spraying device, etc. A cylindrical roll having an alloy film formed thereon is immersed in a solution in which the non-adhesive resin is dissolved, the alloy film layer is impregnated with a predetermined amount of the non-adhesive resin, then polished and finished to a predetermined surface property. Can be created. In the film formation by the thermal spraying method, voids are formed in the alloy layer, and the non-adhesive resin is easily contained therein, which is preferable. The manufacturing method is not limited to this method.

The method of producing a polyester film, particularly a polyethylene terephthalate or polyethylene naphthalate film, using the stretching roll of the present invention means that the film is stretched at a temperature equal to or higher than the glass transition temperature and equal to or lower than the melting point of the film by utilizing the peripheral speed difference of the roll. The production method is characterized in that the production method includes a step of using the stretching roll of the present invention in a stretching step, that is, using the stretching roll in a stretching section. Preferred stretching conditions include a stretching temperature of 90 to 140 ° C. and a stretching ratio of 2.7 to
It is 5.5 times. Since the film produced by this production method has very few surface scratches, it is preferably used for magnetic recording tapes, especially polyester films for magnetic recording tapes for recording digital data such as DVC tapes.

[Method of Measuring and Evaluating Characteristic Values] (1) Hardness Vickers hardness and HV are used as hardness. Using a Vickers hardness tester, a square pyramid diamond indenter with a diagonal angle of 136 ° was used, and the load when a pyramid-shaped depression was formed on the test surface was divided by the surface area obtained from the diagonal length of the permanent depression. HV = 0.1891 × (F / d ² ) HV: Vickers hardness, F: Load [N], d: Average of diagonal length of depression [mm] Is calculated by

A flat plate sample is prepared by using an alloy material for forming a stretching roll and a thermal spraying method, and it is used as a test piece. Measurement is performed at five places, and the average value is determined.

(2) Surface roughness Ry value The surface roughness Ry value is determined by measuring the surface roughness of the stretching roll surface in the ridge direction using a stylus type surface roughness meter. The stylus radius is 2 to 5 μm, the cutoff value is 0.8 mm, and the evaluation length is 4
mm. The Ry value is determined according to JIS B0601. Measure 10 points almost evenly from the whole roll,
The average value is defined as the Ry value.

(3) Number of surface scratches A replica of the stretch roll surface of about 10 cm square was taken from the stretch roll surface using a crosslinkable silicone rubber, and the replica surface was observed using a laser microscope to determine the height or depth. Alternatively, the number of surface flaws whose sum of height and depth is 1.0 μm or more is determined. In addition, 10 surface replicas are evenly taken from the stretching roll and converted into a value of 100 cm ² to obtain the number of surface scratches.

(4) Evaluation of Surface Properties of Film Produced by the Production Method of the Present Invention The surface of the produced film is observed using a laser microscope, and the number of scratches having a height of about 0.25 μm or more is determined. Based on the number of film surface scratches, it was evaluated as 50/100 cm ² or more × 20-49 / 100 cm ² △ 10-19 / 100 cm ² ○ 10 / less than 100 cm ² . X level is a level that is not practical. ◎ is very good, ○ is good, and △ is a practically manageable level.

[0030]

Next, the present invention will be described based on examples.

Example 1 An alloy film of tungsten carbide (80%) and nichrome (20%) was formed on an iron roll core by a plasma spraying method to a thickness of 120 μm, and polydimethyl as a non-adhesive resin was formed. It was impregnated with a toluene solution of a siloxane resin, and was contained in the alloy layer at a ratio of 1.5% by weight. The surface was polished, and a stretching roll was prepared.

This stretching roll is incorporated into a film forming machine and used as a stretching roll for longitudinal stretching. The film is stretched at 95 ° C. by 3.4 times in magnification, 95 ° C. by 3.4 times in magnification, and heat-treated at 210 ° C. By the biaxial stretching method, a smooth polyethylene terephthalate film having a Ra value of 5 nm and a thickness of 6 μm for a base film of a DVC tape was produced for 5 days. Thereafter, the main stretching roll was removed and stored. The use of such a stretching roll was repeated, and this stretching roll was used for a total of 60 days.

A stretching roll used for a total of 60 days and a DV manufactured after using the main stretching roll for a total of 60 days
Table 1 shows the properties of the polyester film for the base film of the C tape.

Example 2 The procedure of Example 1 was repeated, except that the longitudinal stretching was 130 ° C. and 4.1 times, and the transverse stretching was 130 ° C. and 4.1 times.
Smooth polyethylene-2 with a Ra value of 5 nm and a thickness of 4 μm for a base film of C-LP (long play) tape,
Production of 6-naphthalate film was performed for 5 days. Thereafter, the main stretching roll was removed and stored. The use of such a stretching roll was repeated, and this stretching roll was used for a total of 60 days.

The stretching roll used for a total of 60 days and the DV produced after using the main stretching roll for a total of 60 days
Table 1 shows the properties of the polyester film for the base film of the C tape.

Example 3 In the production of the stretching roll of Example 1, an alloy film of tungsten carbide (80%) and nichrome (20%) was coated with 5%.
It was formed with a thickness of 5 μm.

Otherwise, in the same manner as in Example 1, a stretching roll was prepared, and the thickness of the DVC tape for the base film was 6 mm.
Production of a smooth polyethylene terephthalate film having a Ra value of 5 μm and a Ra value of 5 nm was carried out for 5 days. Thereafter, the main stretching roll was removed and stored. The use of such a stretching roll was repeated, and this stretching roll was used for a total of 60 days.

A stretching roll used for a total of 60 days, and a DV manufactured after using the main stretching roll for a total of 60 days.
Table 1 shows the properties of the polyester film for the base film of the C tape.

Example 4 In the production of the stretching roll of Example 1, an alloy film of tungsten carbide (80%) and nichrome (20%) was coated with 4%.
It was formed with a thickness of 80 μm.

Otherwise, a stretching roll was prepared in the same manner as in Example 1, and a 6 μm thick DVC tape base film was used.
Production of a smooth polyethylene terephthalate film with a Ra value of m and 5 nm was carried out for 5 days. Thereafter, the main stretching roll was removed and stored. The use of such a stretching roll was repeated, and this stretching roll was used for a total of 60 days.

A stretching roll used for a total of 60 days and a DV produced after using the main stretching roll for a total of 60 days
Table 1 shows the properties of the polyester film for the base film of the C tape.

Example 5 In the production of the stretching roll of Example 1, the content of the polydimethylsiloxane resin in the alloy layer was set to 0.3% by weight.

Otherwise, a stretching roll was prepared in the same manner as in Example 1, and a 6 μm thick DVC tape base film was used.
The production of a smooth polyethylene terephthalate film with a Ra value of m and 5 nm was carried out for 10 days. Thereafter, the main stretching roll was removed and stored. The use of such a stretching roll was repeated, and this stretching roll was used for a total of 60 days.

The stretching roll used for a total of 60 days and the DV produced after using the main stretching roll for a total of 60 days
Table 1 shows the properties of the polyester film for the base film of the C tape.

Example 6 In the production of the stretching roll of Example 1, the content of the polydimethylsiloxane resin in the alloy layer was set to 15% by weight.

Otherwise, a stretching roll was prepared in the same manner as in Example 1, and a 6 μm thick DVC tape base film was used.
Production of a smooth polyethylene terephthalate film with a Ra value of m and 5 nm was carried out for 5 days. Thereafter, the main stretching roll was removed and stored. The use of such a stretching roll was repeated, and this stretching roll was used for a total of 60 days.

The stretching roll used for a total of 60 days and the DV manufactured after using the main stretching roll for a total of 60 days
Table 1 shows the properties of the polyester film for the base film of the C tape.

Example 7 In the production of the stretching roll of Example 1, the surface layer was buffed after metal plating to reduce the surface roughness. Otherwise, a stretching roll was prepared in the same manner as in Example 1. A Ra value of 5 nm with a thickness of 6 μm was obtained by the same stretching method as in Example 1.
It was attempted to produce a smooth polyethylene terephthalate film, but the main stretching roll used for longitudinal stretching was too smooth and the slip at the time of stretching was very poor, making it difficult to produce a film at the same production speed. For 30 days and production was carried out for 5 days. Thereafter, the main stretching roll was removed and stored. The use of such a stretching roll is repeated 60 times.
This stretching roll was used for a day.

The stretching roll used for a total of 60 days and the DV produced after using the main stretching roll for a total of 60 days
Table 1 shows the properties of the polyester film for the base film of the C tape.

Example 8 In the production of the stretching roll of Example 1, the surface roughness of the iron roll core used was rough, and the surface roughness of the surface of the stretching roll produced by a similar production method was large.

The other conditions were the same as in Example 1, and the thickness was 6 μm.
The production of a smooth polyethylene terephthalate film having a Ra value of 5 nm was performed for 5 days. Thereafter, the main stretching roll was removed and stored. The use of such a stretching roll was repeated, and this stretching roll was used for a total of 60 days.

The stretching roll used for a total of 60 days and the DV produced after using the main stretching roll for a total of 60 days
Table 1 shows the properties of the polyester film for the base film of the C tape.

Example 9 In the production of the stretching roll of Example 1, the iron roll core used had many scratches, and the number of scratches on the surface of the stretching roll manufactured by the same manufacturing method became large.

Otherwise, the thickness was 6 μm in the same manner as in Example 1.
The production of a smooth polyethylene terephthalate film having a Ra value of 5 nm was performed for 5 days. Thereafter, the main stretching roll was removed and stored. The use of such a stretching roll was repeated, and this stretching roll was used for a total of 60 days.

The stretching roll used for a total of 60 days and the DV produced after using the main stretching roll for a total of 60 days
Table 1 shows the properties of the polyester film for the base film of the C tape.

Comparative Example 1 In the production of the stretching roll of Example 1, the polydimethylsiloxane resin solution was not impregnated.

Otherwise, a stretching roll was prepared in the same manner as in Example 1. 6 μm thick by the same stretching method as in Example 1.
Tried to produce a smooth polyethylene terephthalate film having a Ra value of 5 nm, but the film at the time of stretching adhered to the main stretching roll used for longitudinal stretching, and it was impossible to produce a film even when the stretching temperature was lowered. Was.

Table 1 shows the properties of the obtained stretching rolls.

Comparative Example 2 In the production of the stretching roll of Example 1, the alloy metal was changed to Ni.

Otherwise, a stretching roll was prepared in the same manner as in Example 1, and a 6 μm thick DVC tape base film was used.
Production of a smooth polyethylene terephthalate film with a Ra value of m and 5 nm was carried out for 5 days. Thereafter, the main stretching roll was removed and stored. The use of such a stretching roll was repeated, and this stretching roll was used for a total of 60 days.

The stretching roll used for a total of 60 days and the DV produced after using the main stretching roll for a total of 60 days
Table 1 shows the properties of the polyester film for the base film of the C tape.

[0062]

[Table 1]

[0063]

As is clear from the characteristics shown in Table 1, the stretching roll of the present invention, that is, the stretching roll having a metal layer containing a non-adhesive resin on the surface layer and having a hardness HV of 900 or more on the surface layer. Gives a polyethylene terephthalate film and a polyethylene-2,6-naphthalate film which have excellent durability and are extremely scratch-free even after repeated use for a long period of time.

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3J103 AA02 AA51 FA09 FA12 FA17 GA02 GA12 GA52 HA04 HA22 HA31 4F210 AA24 AG01 AH38 AJ02 AJ03 AJ09 QA03 QG01 QN01

Claims (5)

[Claims] 1. A stretching roll for producing a film, wherein the surface layer comprises a metal layer containing a non-adhesive resin, and the metal layer has a hardness HV of 900 or more. 2. The method according to claim 1, wherein the surface roughness Ry value of the metal layer is 0.3 μm or more.
1.0 μm, and the number of surface flaws whose height or depth or the sum of height and depth is 1.0 μm or more is 40/100 cm.
^{2. The} stretching roll for producing a film according to claim 1, wherein the number is ² or less. 3. A method for producing a polyester film, comprising using the stretching roll according to claim 1 in a stretching step. 4. The method according to claim 3, wherein the polyester film is for a magnetic recording medium. 5. The method according to claim 4, wherein the magnetic recording medium is a digital recording type magnetic recording tape.