JP3203997B2 - Thermoplastic resin sheet manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for heating or stretching a thermoplastic resin sheet using a pair of rolls.
More specifically, in an apparatus for heating or stretching a thermoplastic resin sheet using a pair of rolls, without renewing a roll having a press mechanism for a long period of time, a thermoplastic resin sheet capable of efficiently producing an object to be processed with high quality. It relates to a manufacturing device.

[0002]

2. Description of the Related Art Generally, in order to stretch or heat-treat a thermoplastic resin sheet, a method of using a hot plate or a roll to contact and heat a material to be heated, or a method of heating in a non-contact manner using hot air or infrared rays. However, a roll heating method is often adopted, particularly because of uniform heating and high heat transfer efficiency. The heating roll includes a so-called heat medium circulation system in which a liquid is circulated or steam is passed through the inside of the heating roll, and an induction heating system in which an electromagnetic induction coil is provided inside and heated by an induction current.

[0003] These heating rolls are formed by processing a metal such as iron or aluminum, or a composite material of a plastic into a cylindrical shape, coating it with a plating or a plastic resin or rubber, and further finely polishing it according to the application. Processed ones are used. Since this method involves contact with the material to be heated, it is necessary to consider especially the abrasion resistance, heat resistance, non-adhesion, surface smoothness, etc., for example, chrome plating, fluorine resin coating, ceramic spraying, silicone resin coating It is possible to use it after processing such as molding.
8672 and JP-A-56-51331.

Further, when heated and heated, it has non-adhesiveness,
Japanese Patent Application Laid-Open No. 62-149413 discloses a thermoplastic resin, which has a smooth surface, is excellent in weather resistance and abrasion resistance, and can secure an appropriate elasticity by further coating thickly . It is disclosed as. In particular, in the stretching step or the tension or relaxation heat treatment step even in the heating and heating step, there is a portion having a press mechanism that requires a nip before and after it, but because it requires heat resistance, abrasion resistance and elasticity. Nip rolls coated with various resins are used.

[0005]

However, in an apparatus having such a press mechanism, the roll, particularly at the portion through which the sheet ears pass, is severely worn, and it is satisfactory even with a high-performance resin roll. Could not be used. This is because the sheet that passes through has a certain thickness, and the ears of the sheet are often set thicker in consideration of production stability in the later process. This is because a larger press pressure is applied to the portion where the heat is applied.

Another problem is that, in general, in the above-described press mechanism, pressure is often applied to a shaft end portion of a roll to function, and therefore, a distribution of press pressure in a pair of rolls is considered. The pressure near the shaft end is higher than that at the center. This also causes an increase in the pressing pressure at the ears of the passing sheet.

Further, the rotational speeds of the pair of rolls are slightly different from each other, and the three speeds of the thermoplastic resin sheet, the drive-side roll, and the rotatably supported floating roll are different from each other. I knew it was. That is, generally, in a roll having a press mechanism, one side of a pair of rolls is rotatably supported, and a rotational force is obtained through a pressed sheet. It was also found that a rotational force was obtained from this, and a speed difference occurred between the three.

In the wear caused by such a cause,
Generally, the wear of the resin-coated roll is more intense than that of the passing sheet, which shortens the life of the roll. In addition, there is a problem that the abrasion powder is mixed into the product to significantly deteriorate the quality. Continued use of a roll that is still worn causes quality defects such as uneven stretching.

[0009]

Means for Solving the Problems In the processing of a sheet using a pair of rolls having a press mechanism, the present inventors improve the wear resistance of a plastic resin or rubber roll used and improve the product quality. As a result of intensive research on the means, it has been found that abrasion can be suppressed by notching a portion corresponding to the sheet ear portion of at least one of the pair of rolls and the outside thereof with a certain taper. That is, the thermoplastic resin sheet manufacturing apparatus according to the present invention heats and raises the temperature of the thermoplastic resin sheet ,
Before and after the stretching, straining or relaxation heat treatment,
In a device using a roll having a pair of press mechanisms, the surface of at least one roll is coated with plastic resin or rubber, and the roll is gradually moved from the position corresponding to the edge of the sheet to the roll end. Notch processing is performed to reduce the diameter, and the notch
The starting point position of the sheet is in the longitudinal direction of the roll,
Within 200mm inside and 50m outside from width direction edge
m .

Hereinafter, the present invention will be described in detail. The thermoplastic resin sheet used in the present invention is not particularly limited, but typical examples include polyethylene terephthalate, polyethylene-2,6-naphthalate, polypropylene, nylon-6, and polyphenylene sulfide.

The thermoplastic resin sheet of the present invention comprises, for example, a molten polymer made of the above-described thermoplastic resin,
Using an extruder, extruding a sheet from a die having a slit-shaped discharge port and then quenching to form an unstretched resin sheet, or stretching the unstretched sheet uniaxially or biaxially. Formed by The thickness of the resin sheet is 5 μm to 3000 μm. If it is less than 5 μm, it is too thin, and if it exceeds 3000 μm, it is too thick and the effect of the present invention is small.

[0012] The roll ring of the roll used in the present invention is made of a metal such as iron or aluminum or a composite material of plastic, which is provided with a cavity for introducing a liquid or gas for heat exchange therein. In addition to the above, a thick metal core for disposing an electromagnetic induction coil therein and supplying an induced current to generate heat can be used. In these members, a heat pipe or the like for temperature equalization can be embedded in the cylindrical wall thickness.

Further, the press mechanism for a pair of rolls in the present invention means that air pressure, hydraulic pressure,
It may have a mechanism for pressing by a screw mechanism or the like, or may have a mechanism for pressing a roll having a similar press mechanism on the entire surface of the roll or a part thereof, and further simply weigh the roll itself. Alternatively, a pressing mechanism may be used. Further, a mechanism for equalizing the press pressure may be provided inside the roll. Further, the shaft end of the roll may be rotatably supported or driven, but it is preferable that at least one roll is driven and the other roll is rotatably supported.

The plastic resin or rubber coated on the roll of the present invention includes silicone resin, neoprene rubber, ethylene propylene rubber, hypalon rubber, NBR
Rubber or the like can be used, but is not limited thereto. The thickness of the plastic resin or rubber used in the present invention is preferably 1 mm or more, more preferably 5 mm or more. If it is less than 1 mm, the function of the press is impaired, which is not preferable. The rubber hardness is preferably in the range of 35 ° to 95 ° in Shore hardness. If the angle is less than 35 °, when used as a press, wear is severe and it is not practical. One of the features of the present invention is that the effect is remarkably exerted on rubber having higher hardness. However, if the hardness exceeds 95 °, the function as an original rubber, that is, elasticity is impaired, so that it is preferable. Absent.

On the other hand, the other of the pair of rolls may be a roll coated with the above-mentioned plastic resin or rubber, and may be a metal or a reinforced plastic such as FRP surface-treated with chrome plating or ceramic coating. A roll using a core may be used. However,
It is not limited to these.

The surfaces of a pair of rolls are generally polished flat, but a drum-shaped crowning may be provided so that pressure is uniformly distributed over the entire width. However, the effect of the present invention can be expected only by crowning. Can not. A high effect can be expected by using together with the tapered notch as in the present invention.

The tapered notch of the present invention must be cut so that the diameter gradually decreases from the position corresponding to the sheet edge of the roll toward the longitudinal end of the roll. This notch processing may be performed on only one of the pair of rolls, or may be performed on both rolls. As the range of the processing, the starting point of the notch processing of one of the pair of rolls is set to a position within 200 mm inward in the longitudinal direction of the roll from the edge in the width direction of the sheet, and the sheet edge outward from there. 必to be from the edge to a position of less than 50mm
It is necessary. If the notch processing starts from the inner side at a distance of more than 200 mm from the edge of the sheet, the pressing pressure at the ears becomes weak and the original pressing cannot be performed, which is not preferable. Also,
Starting from outside the sheet edge by more than 50 mm is not preferable because the portion where the pair of rolls are in contact with each other becomes wide.

[0018] The shape of cutout which is, viewed in vertical cross-section including the roll axis, can be configured to form a linearly tapered or curved. In the case of a curve, the curve is a curve that protrudes outward in the roll radial direction. Further, the angle of the tapered straight line or curve with respect to the non-notched portion on the roll surface is preferably 0.01 to 2 °. The purpose of forming the taper is to change the press pressure gradually,
Since the ear portion of the resin sheet is generally formed gradually thicker toward the end of the ear, it is necessary to form a taper in order to cope with the changing thickness.

Here, the tapered notch is easily formed into a linear taper from the viewpoint of workability, but a curved taper (a curved surface taper as a roll surface) is more preferable because it can more appropriately cope with a change in the thickness of the lug portion. When the resin sheet is thin, it is necessary to form a smaller angle, and when the resin sheet is thick, it is necessary to form a larger angle, but in order to process resin sheets of various thicknesses, Is preferably in the range of 0.01 to 2 °. Regarding the angle in the case of a curved surface, a range of 0.01 to 2 ° is preferable as an angle formed by a non-cut portion of the roll surface at a position of 200 mm measured from the taper start point (that is, the notch start portion). It is.

In the present invention, when the position and shape of the ear portion of the thermoplastic resin sheet passing therethrough are always constant, the outer portion of the ear portion should be cut out more than the notch taper of the present invention. This is preferable because the effect can be further increased.

A typical embodiment of a thermoplastic resin sheet manufacturing apparatus according to the present invention will be described with reference to the drawings. FIG.
Shows a pair of roll portions having a press mechanism in the thermoplastic resin sheet manufacturing apparatus according to one embodiment of the present invention. In the figure, reference numerals 1 and 2 denote a pair of rolls. In the present embodiment, the roll 1 is a driven roll, a roll 2
Are provided on the drive roll. The roll 1 is pressed against the roll 2 by a press pressure P from a shaft by an appropriate press mechanism, and the thermoplastic resin sheet 3 running between the two rolls is nipped.

In this embodiment, the surface of one roll 1 is coated with a plastic resin, more specifically, a silicone resin, and the surface of the other roll 2 is chrome-plated. At both ends in the longitudinal direction of the roll 1, notch processing (taper processing) is performed so that the diameter gradually decreases from a position corresponding to the ear 3 a of the sheet 3 toward the roll end. The starting point of the notch processing portion 4 is set in the longitudinal direction of the roll 1 so as to be within 200 mm inside and 50 mm outside the width direction edge of the sheet 3. The longitudinal cross-sectional shape of the notched portion 4 including the axis of the roll 1 is formed in a linear tapered shape, and the angle θ of the straight portion with respect to the non-notched portion of the roll surface is:
It is set in the range of 0.01 to 2 °.

FIG. 2 shows another embodiment, in which a thermoplastic resin sheet 13 is nipped between a pair of rolls 11 and 12. In the present embodiment, the cutout portion 14 of the roll 11 is formed in a curved tapered shape that protrudes radially outward when viewed in a vertical cross-sectional shape including the axis of the roll 11. The range of the starting point of the notch processing portion 14 in the roll longitudinal direction is the same range as that shown in FIG. The angle θ of the taper curve with respect to the non-notched portion of the roll surface at a position 200 mm away from the notched portion on the inner side in the longitudinal direction of the roll is set in the range of 0.01 to 2 °.

FIG. 3 shows still another embodiment, in which a thermoplastic resin sheet 2 is sandwiched between a pair of rolls 21 and 22.
3 is nipped. In this embodiment, the cutout portion 24 of the roll 21 is formed in a two-stage linear taper shape. Notch processing portion 24 on the inner side when viewed in the roll longitudinal direction
a substantially corresponds to the position of the ear portion 23a of the seat 23,
The outer cutout portion 24b is set outside the ear portion 23a. The notching unit 24a, an angle theta ₁ with respect to the non-notching of the roll surface is set in a range of 0.01 to 2 °, the angle of the notching portions 24b theta
₂ is set to an angle larger than theta _1. As described above, in the present invention, the shape of the cutout processing portion can take various modes.

Hereinafter, the present invention will be described with reference to examples. In the present invention, characteristics and evaluations were measured by the following methods. (1) Roll wear The following judgment was made by visual observation. ◎: No abrasion ○: Abrasion is observed but no abrasion powder is scattered △: Abrasion is observed and abrasion powder is adhered to the roll ×: A cut due to abrasion is formed in the ear part

(2) Abrasion powder in the sheet Biaxially stretched and then heat-treated, the obtained sheet (film) is slit and rolled up, and the number of foreign matters visible from the surface of the product roll on the ear side of the resin sheet is counted around the product roll. 1m counted
^It was converted to ^two .

(3) Rubber hardness Measured using a C200 type hardness meter according to JIS-K6301.

[0028]

【Example】

Examples 1, 2, and 3 A silicone resin was coated on a metal roll surface and molded to a thickness of 10 mm, a rubber hardness of 60 ° shore, and an outer diameter of 200 mm.
Silicone roll. On the other hand, a roll obtained by spraying a ceramic on a 200 mm metal roll was also used as a silicone roll and a pair of press rolls on the low-speed stretching side of a longitudinal stretching apparatus. As for the press pressure, air pressure was applied to the shaft end of the roll using an air cylinder to apply a pressure of 10 kg / cm.

Since the positions of the ears passing through the silicone roll vary depending on the thickness of the resin sheet, the average value is calculated. A taper starting point is set at 50 mm inward from the edge of the sheet, and a straight line of 0.15 ° is obtained. Notched by taper (Example 1). The taper starting point was 20 mm outward, and the linear taper angle was 2 ° (Example 2). Further, a position 150 mm inward from the edge of the sheet is set as a taper start point, and a curved surface taper based on a quadratic curve is formed at an angle of 0.05 °.
(Example 3).

The polyethylene terephthalate was dried by a conventional method, melted using an extruder, and discharged from a wide die to obtain an unstretched sheet of 80 μm to 200 μm. This was pre-heated at 97 ° C., the temperature of the press roll was set at 110 ° C., and stretched longitudinally at a stretch ratio of 3.5 to 4.5 times,
Next, the film was transversely stretched 3.6 times at a preheating temperature of 105 ° C. to 115 ° C. and further heat-treated to obtain a biaxially stretched polyester film of 7 μm to 12 μm, which was slit to obtain a predetermined roll. The wear condition of the roll was observed, and the number of foreign substances on the product roll was counted. Table 1 shows the results.

Comparative Examples 1, 2, and 3 In Example 1, the test was performed using a normal (that is, a flat roll surface) silicone roll in which a portion through which a portion corresponding to a lug portion of a resin sheet passed was not cut out (Comparative Example). 1).
Further, in Example 2, the taper start point was set to 100 mm outside the ear passage portion (from the sheet edge) (Comparative Example 2). Further, in Example 3, the taper start point was set to 300 mm inside the sheet edge (Comparative Example 3).

[0032]

[Table 1]

[0033]

According to the present invention, at least one of the pair of rolls having the press mechanism can be used for a long period of time because the abrasion of the ear-passing portion of the resin sheet of the roll is suppressed.
In addition, since the amount of abrasion powder is reduced, the amount of foreign substances caught in the product is also reduced, and the quality of the product can be improved.

[Brief description of the drawings]

FIG. 1 is a front view of a pair of rolls according to an embodiment of the present invention.

FIG. 2 is a front view of a pair of rolls according to another embodiment.

FIG. 3 is a front view of a pair of rolls according to still another embodiment.

[Explanation of symbols]

 1, 11, 21 Roll having notched portion 2, 12, 22 Other roll 3, 13, 23 Thermoplastic resin sheet 4, 14, 24 Notched portion

Continuation of the front page (51) Int.Cl. ⁷ identification code FI B29K 101: 12 B29L 7:00 (56) References JP-A-63-92797 (JP, A) Japanese Utility Model Application Laid-open No. 2-94853 (JP, U) (58) Field surveyed (Int.Cl. ⁷ , DB name) B29C 55/00-55/30 B29C 35/02-35/08 B29C 43/24 B29C 43/46 B29C 47/88-47/90

Claims (7)

(57) [Claims] 1. A thermoplastic resin sheet is heated and heated and stretched.
At least before and after the heat treatment process
In an apparatus using a roll having a pair of press mechanisms, the surface of at least one roll is coated with a plastic resin or rubber, and the diameter of the roll is gradually reduced from a position corresponding to the edge of the sheet to the roll end. Notch processing is performed so that
The starting point position is the position of the sheet in the longitudinal direction of the roll.
Within 200mm inside and 50mm outside from width direction edge
An apparatus for manufacturing a thermoplastic resin sheet, characterized in that the range is within the range . 2. A shaft of the roll of the notched portion.
The apparatus for producing a thermoplastic resin sheet according to claim 1, wherein the longitudinal sectional shape including the core is a straight line . 3. The non-linear shape of the roll surface of the roll.
The angle with respect to the notched portion is 0.01 to 2 °,
An apparatus for manufacturing a thermoplastic resin sheet according to claim 2 . 4. The shaft of the roll of the notched portion
The vertical cross-sectional shape including the core is convex outward in the roll radial direction.
The apparatus for producing a thermoplastic resin sheet according to claim 1, wherein the apparatus is a curve . 5. The method according to claim 5, wherein said curve is located inside the roll in the longitudinal direction.
At a position 200 mm away from the notch processing start part
To the notched portion of the roll surface of the roll
The apparatus for producing a thermoplastic resin sheet according to claim 4, wherein the angle is 0.01 to 2 ° . 6. The thermoplastic resin sheet has a thickness of 5 to 300.
The apparatus for producing a thermoplastic resin sheet according to claim 1, wherein the thickness is 0 μm . 7. A plastic resin or rubber having a thickness of 1
The thermoplastic resin sheet manufacturing apparatus according to any one of claims 1 to 6, wherein the rubber hardness is 35 to 95 degrees in Shore hardness of not less than mm.