JPH11235747A - Roll apparatus for molding sheet/film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the transfer of a mirror surface or an embossed pattern with high accuracy without generating residual strain. SOLUTION: In a roll apparatus for molding a sheet/film by introducing a sheet-shaped molten resin extruded from an extrusion molding machine into the gap between a main roll 26 and a press roll 27 to press the same, the main roll 26 is constituted of a high rigidity metal roll and the press roll 27 is constituted of a double cylinder consisting of a thin-walled metal outer cylinder 31 having flexibility and the high rigidity metal inner cylinder 34 concentrically and ingternally fitted to the thin-walled metal outer cylinder 31 so as to leave the feed space 33 of a cooling fluid 32 and the relation between the wall thickness of the thin-walled metal outer cylinder 31 and a roll radius is set to the wall thickness of the thin-walled metal outer cylinder 31/roll radius <=0.03 to enable elastic deformation. The thin-walled metal outer cylinder is elastically deformed to ensure a predetermined contact length (k) between the cylinder 31 and the main roll to mold a resin without forming a bank.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extruded sheet or film of plastic, a sheet material, a sheet material, a composite material such as paper or fiber and the like, and cooling to form a sheet product, a film product, a laminate product. The present invention relates to a roll device for forming a sheet and a film for producing the same.

[0002]

2. Description of the Related Art Conventionally, thermoplastic resin extrusion molding methods include a metal roll compression molding method shown in FIG. 11 and a rubber roll compression molding method shown in FIG.

In the metal roll press forming method, a sheet-like molten resin 1 is supplied from an extruder via a T-die 2 onto a main roll 3 and a holding roll 4 arranged in parallel with each other.
While being pressed between the two rolls 3 and 4 and wound around the surface of the main roll 3, an accurate thickness dimension and a mirror surface or an embossed pattern on the surfaces of the rolls 3 and 4 are transferred and formed. In many cases, these rolls 3 and 4 are made of a rigid metal roll having a diameter of 200 to 500 mm and a thickness of 15 to 30 mm, and a cooling fluid 5 such as water or oil is filled in the hollow portions of the rolls 3 and 4. The supplied resin is configured to cool the resin to an appropriate temperature. Since the rolls 3 and 4 have high rigidity, there is no deformation of the surfaces of the rolls 3 and 4 by pressing the molten resin sheet 1, and a bank in which the surplus of the supplied molten resin sheet accumulates on the rolls 3 and 4. 1a occurs.

[0004] In the rubber roll pressure forming method, a cylindrical rubber 14b is coated on the surface of a main body 14a of a press roll 14, so that the cylindrical rubber 14b of the press roll 14 can maintain the main roll 3 even at a low pressing force. The molten resin sheet 1 is deformed along the surface, and all the molten resin sheets 1 are sent to the clamping portion to
a is not formed.

[0005]

However, in the metal roll squeezing method, the amount of the bank 1a depends on the squeezing pressure, the difference between the thickness of the molten sheet and the roll interval, and the difference between the molten sheet supply speed and the roll peripheral speed. Depends on the viscosity and temperature of the molten resin, the smaller the thickness of the sheet / film, the lower it is necessary to reduce it.If the amount of banks is increased more than the molten resin allows, a horizontal wavy shape called a bank mark will appear on the surface of the product. And the product becomes defective. When the bank amount is appropriately maintained within the allowable range, a buffering action is provided to make good contact with the clamping portion, so that the mirror surface and the embossed pattern are satisfactorily transferred.

However, when the bank 1a is provided, the resin sheet is distorted at the pinching portion, and the distortion depends on the elastic property of the resin. When the roll temperature difference is large, it tends to increase in proportion.

A sheet having such residual distortion cannot be used for a display device such as a liquid crystal display device due to irregular reflection of light or a birefringence phenomenon, and the distortion is recovered with time. There is a problem in that the shape cannot be applied to stationery and the like because the initial shape cannot be maintained. Also, the molding thickness is limited to about 0.3 mm.

On the other hand, in the rubber roll press molding method, since the molding can be performed without forming a bank, no residual distortion occurs. However, the rubber surface of the holding roll 14 cannot obtain a mirror surface like a metal roll. Also, high speed molding is not possible due to the low thermal conductivity of rubber. Further, since the clamping pressure allowed by the rubber is small, there was a problem that the embossed pattern could not be sufficiently transferred, and the life of the rubber was short.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a sheet / film forming roll apparatus capable of transferring a mirror surface or an embossed pattern with high accuracy without residual distortion.

[0010]

According to the first aspect of the present invention, a sheet-like molten resin extruded from an extruder is introduced between a main roll and a holding roll to perform pinching molding. A roll device for forming a sheet and a film, wherein a main roll is constituted by a high-rigidity metal roll, and a holding roll is provided with a thin metal outer cylinder having flexibility and a space for flowing a cooling fluid. A double cylinder consisting of a highly rigid metal inner cylinder fitted in the same outer cylindrical shape to the metal outer cylinder, wherein the thickness of the thin metal outer cylinder / roll radius ≦ 0.03
It is what it was.

According to the above construction, the contact length to the main roll can be secured by utilizing the elastic deformation of the thin metal outer cylinder in the same manner as in the rubber roll pressure forming method. An optically excellent resin film / sheet free from residual distortion and free from irregular light reflection and birefringence can be produced by molding. In addition, since both the front and back surfaces are pressed by the metal surface, the mirror surface and the embossed pattern can be transferred with high precision. Furthermore, since the metal inner cylinder is arranged inside the thin metal outer cylinder via the cooling fluid flow-in space, the strength of the holding roll can be secured while maintaining the flexibility of the thin metal outer cylinder. Furthermore, rapid cooling is possible by the thin metal outer cylinder having a small thickness, and it is possible to realize the production of a resin film / sheet that is thin and mirror-clear and has no residual distortion, which was impossible by the conventional method.

According to a second aspect of the present invention, the press roll having the above structure is formed in a drum shape in which the outer diameter of the center of the thin metal outer cylinder is larger than the outer diameter of both ends. According to the above configuration, by performing crowning in which the outer diameter of the central portion is larger than the outer diameters of the both ends, the thin metal outer cylinder is formed as the pinching load increases due to the low flexibility of the ends. It is possible to prevent the resin film / sheet from being deformed into a concave shape (hourglass shape) and prevent the resin film / sheet from being thickened at the center.

According to a third aspect of the present invention, a thin wall portion for reducing the wall thickness is formed in the vicinity of both ends of the thin metal outer cylinder of the holding roll in the circumferential direction. According to the above configuration, since the flexibility can be improved at both ends of the thin metal outer cylinder by the thin thick portion, the thin metal outer cylinder becomes concave (hourglass-shaped) as the pinching load increases.
And the resin film / sheet can be prevented from being thickened at the center.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, an embodiment of a horizontal roll forming apparatus according to the present invention will be described with reference to FIGS.

As shown in FIG. 5, the sheet / film extrusion forming apparatus provided with the horizontal roll forming apparatus 21 has an extruder 23 disposed on a pedestal 22 and feeds a thermoplastic resin raw material supplied from a raw material hopper 24. The extruder 23 heats and kneads and supplies the sheet-like molten resin to the horizontal roll forming apparatus 21 from a T-die 25 arranged at a resin outlet 23a. The horizontal roll forming apparatus 21 is a main roll (first chill roll) that receives the sheet-like molten resin from the T-die 25.
26 and a holding roll 27; a second chill roll 29 for further forming a product sheet 28 from the main roll 26;
It comprises a plurality of guide rollers 30 for sending out the product sheet 28 from the second chill roll 29.

The main roll 26 is, as shown in FIG.
Cooling fluid with the same rigid roll as before, made of a seamless steel pipe with a wall thickness of about 20 to 30 mm and finished with a mirror-like or embossed uneven surface, and the inside can control the roll temperature according to the molding resin material A flow space (water, oil, etc.) is formed.

As shown in FIG. 1 and FIG. 2, the press roll 27 includes a thin metal outer cylinder 31 made of a flexible seamless stainless steel pipe and a cooling fluid (such as water or oil) 3.
It is configured as a double cylinder consisting of a highly rigid metal inner cylinder 34 which is fitted in the thin metal outer cylinder 31 coaxially with two flow spaces 33 therebetween.

That is, the pressing roll 27 has outer cylinder supporting flanges 42A, 42B on the rotating shafts 41A, 41B at both ends.
Are attached, and these outer cylinder supporting flanges 42A, 42
A thin metal outer cylinder 31 is attached between the outer peripheral portions of B.
Further, a fluid supply pipe 45 is disposed coaxially in a fluid discharge hole 43 which is formed in the axis of one rotary shaft 41A and forms a fluid return passage 44, and the fluid supply pipe 45 is thin. It is connected and fixed to a fluid shaft cylinder 46 arranged at a shaft center in the metal outer cylinder 31. Inner cylinder support flanges 47a and 47b are attached to both ends of the fluid shaft cylinder 46, respectively.
Approximately 15 to 20 from between the outer peripheral portions of the inner cylinder supporting flanges 47a and 47b to the other outer cylinder supporting flange 42B.
A metal inner cylinder 34 having a thickness of about mm is attached. A cooling fluid flow space 33 of, for example, about 10 mm is formed between the metal inner cylinder 34 and the thin metal outer cylinder 31. An outlet 34a and an inlet 34b communicating with the intermediate passages 48A, 48B outside the cylinder support flanges 47a, 47b are formed respectively.

Then, the cooling fluid supplied to the fluid supply pipe 45 via the rotary joint 49 is sent to the fluid shaft cylinder 46, and from the other end side opening 46a of the fluid shaft cylinder 46 via the intermediate passage 48B and the inflow port 34b. To the fluid supply space 33, and from the outlet 34a at one end of the metal inner cylinder 34 to the fluid return passage 44 and the rotary joint 49 via the intermediate passage 48A.

The thickness of the thin metal outer cylinder 31 is reduced within a range in which the thin cylinder theory of elasticity can be applied in order to provide flexibility, flexibility, and resilience close to rubber elasticity. The flexibility evaluated by the thin-walled cylinder theory is as follows:
/ R: expressed by the roll radius, and the smaller the value of t / r, the higher the flexibility. In the case of the holding roll 27, the optimum condition is obtained when the flexibility is t / r ≦ 0.03. Generally, a generally used holding roll has a roll diameter: R =
200 to 500 mm (roll radius r = R / 2), effective roll width: L = 500 to 1600 mm, and has a horizontally long shape with r / L <1. Then, as shown in FIG. 6, for example, a roll diameter: R = 300 mm, and a roll effective width: L = 1200
In the case of mm, the appropriate range of the thickness t is 150 × 0.03 =
4.5 mm or less, but the molten sheet width is 1000 mm
When the average linear pressure is 10 kg / cm, the equivalent spring constant is made equal by setting the thickness of the thin metal outer cylinder 31 to 3 mm as compared with the rubber roll having the same shape. Is about 9 mm, which is almost the same as the contact length of the rubber roll, which is about 12 mm. The amount of deflection at this contact length: k is about 0.05 to 0.1 mm.

Here, t / r ≦ 0.03, but a general roll diameter: R = 200 to 500 mm (roll radius r
= R / 2), particularly when the range is 2 mm ≦ t ≦ 5 mm, sufficient flexibility can be obtained, and the thickness can be easily reduced by machining. High-precision processing cannot be performed), which is in an extremely practical range.

The converted value of 2 mm ≦ t ≦ 5 mm is 0.008 ≦ t / r ≦ 0.05 with respect to a general roll diameter, but in practical use, t / r の 0.03. It is preferable to increase the wall thickness in proportion to the roll diameter. For example, when the roll diameter is R = 200, t = 2 to 3 mm, and the roll diameter is:
For R = 500, t is selected in the range of 4 to 5 mm.

Further, since the thin metal outer cylinder 31 has both ends supported by the outer cylinder supporting flanges 42A and 42B and has low flexibility, the thickness accuracy of the product sheet 28 may be reduced. For this reason, as shown in FIG.
= (Total roll width Lo-roll effective width L) / 2 is set to a value that is twice that of a conventional metal roll. The roll play width ΔL is about 200 mm (about 100 mm for a conventional metal roll). In FIG. 3, L1 indicates the overall roll width Lo of the conventional metal roll.

Further, the thin metal outer cylinder 31 has higher flexibility by reducing the wall thickness. However, as the clamping force between the main roll 26 and the holding roll 27 is increased, the flexibility of both ends is increased. Due to the low height, the holding roll 27 is concavely curved from the center to the end, and the thickness of the product sheet 28 becomes thicker toward the center. In extreme cases, the main roll 26 and the holding roll 27 may come into contact at both ends. There is.

In order to solve the above problem, in this embodiment, the thin metal outer cylinder 31 is formed in a drum shape in which the outer diameter at the center is larger than the outer diameters at both ends by a crowning amount: C. Thereby, it is possible to prevent the thickness of the central portion of the product sheet 28 from being increased. In FIG. 3, the amount of crowning: C is 0.05 although exaggerated and depends on the characteristics of the molten resin.
A sufficient correction effect can be obtained in a range of 0.2 mm.

FIG. 4 shows another means for preventing the thin metal outer cylinder 31 from becoming drum-shaped as the clamping force increases.
As shown in FIG. 5, grooves 51, which are thin portions that reduce the thickness: t by the thickness reduction amount: h, are formed in the vicinity of the ends in the circumferential direction. The grooves 51 can enhance the flexibility of both ends of the thin metal outer cylinder 31 without pressing the thin portions at the ends of the product sheet 28,
6 can be prevented from coming into contact with the press roll 27. Here, the appropriate range of the wall thickness reduction: h in the groove portion 51 is in the range of 70% to 50% with respect to the thickness t. If the thickness exceeds this range, the improvement in flexibility is small. This is because the strength of the outer cylinder 31 is insufficient. The groove 51 is formed at a position where the outer cylinder support flange 42 is not buffered. The pressing roll 27 having a roll width Lo is 100 mm to 150 mm from the end face. The width of the groove 51 is 50 mm.
If the thickness exceeds this range in the range of 100 mm to 100 mm, appropriate flexibility cannot be obtained.

FIG. 7 shows the effect of the groove 51. Roll effective width: L = 1000 mm, wall pressure: t =
The linear pressure distribution and displacement amount when a linear pressure of 10 kg / cm is applied to the 4 mm holding roll 27 in the case of forming the groove portion 51 with the wall thickness reduction: h = 2 mm and the flat roll having no groove portion, respectively. Is shown. According to the analysis results,
The roll having the groove 51 is, as compared with the flat roll,
The flattening of the sheet thickness distribution is improved from the amount of displacement, and the rate of increase of the linear pressure at the end of the roll is low. Therefore, the uniformity of the thickness of the product sheet 28 is improved by the grooves 51. In addition, end contact between the main roll 26 and the holding roll 27 can be prevented.

In this case, the groove 51 is inserted into the thin metal outer cylinder 31.
Although it was formed on the front side, it may be on the back side or both sides.
Further, it is sufficient that the groove is formed in a thin shape without having to be a visually clear groove shape.

The crowning C and the groove 51 may be used alone, but by combining them, the adverse effect of the curvature of the holding roll 27 can be more effectively eliminated.

Example 1 Heat-resistant and transparent high-performance resin (JS
R company, trade name "ARTON", glass transition temperature 180
° C) at 120 ° C for 1 hour, and then T-die (effective width 10) in a single screw extruder (65 mm diameter, L / D = 32).
5 with a double press roll (thin metal outer cylinder thickness 4 mm, with crowning and groove processing) of FIG. 5 and a conventional rigid metal roll. FIG. 8 shows the result of forming a sheet using the vertical three-roll method. FIG. 9 shows the dimensions of the roll used here.

According to the above experimental results, although the surface property and the transparency are the same between the method of the present invention and the conventional method, there is a remarkable difference in the presence or absence of residual strain. , Almost no distortion level, and was sufficiently usable for optical applications. In addition, the clamping pressure is 7 k
The same experiment was performed at g / cm, but the surface properties and transparency and the presence or absence of residual strain were not changed.

Example 2 Using an undried solid-phase polymerized PET resin having an intrinsic viscosity (IV) of 0.8, a 2-vent co-rotating twin-screw extruder (57 mm in diameter, L / D = 40) was used to prepare T. A die (effective width: 1000 mm, lip interval: 0.8 mm) was attached, and the double press roll of the present invention (thin metal outer cylinder thickness 4)
FIG. 10 shows the result of forming an A-PET film using a roll forming apparatus having a thickness of 0.1 mm (without crowning and groove processing).

The PET resin has a low melt viscosity and has the property of becoming transparent when rapidly cooled and solidified. With the cooling capacity of a conventional thick metal roll, a thin sheet or film having a thickness of 0.2 mm or less is sandwiched. Pressing was extremely difficult. However, by using the double pressing roll 27 of the present invention, a transparent film product having a thin mirror surface having a thickness of 0.14 mm and having no residual distortion could be manufactured. Therefore, the holding roll 27 of the present invention can not only reduce and reduce the residual distortion, but also can rapidly and uniformly cool the molten resin due to the small thickness of the thin metal outer cylinder 31, thereby rapidly cooling the resin. As a result, it has been found that a transparent thin film / sheet having no residual distortion can be favorably formed. Although a PET resin is exemplified here, a film product having no residual distortion with a thin mirror surface by rapid cooling can be manufactured using a resin such as polycarbonate (PC).

According to the above embodiment, the thin metal outer cylinder 3
By utilizing the elastic deformation obtained in the range of thickness / roll radius ≦ 0.03 of 1, the equivalent spring constant and the contact length of the pressing portion are obtained in the same manner as in the rubber roll pressing method. The molten resin can be pinched and molded without any residual resin, and a resin film / sheet suitable for optical applications without residual distortion can be produced. In addition, the obtained molded resin film / sheet can transfer the mirror surface and embossed pattern similar to the metal roll compression molding method, as well as the adhesion to the roll surface and the short service life, as compared with the rubber roll compression molding method. There is no problem such as. Furthermore, rapid cooling can be performed by the thin metal outer cylinder 31, so that high-speed molding can be performed, and further rapid cooling can be performed as compared with the metal roll compression molding method. Even with this, it is possible to form a mirror surface at high speed with a thin wall having no residual distortion.

The outer diameter at the center of the thin metal outer cylinder 31 is larger than the outer diameters at both ends by a crowning amount: C = 0.05-0.
Since it is formed in a large drum shape within the range of 2 mm, it is possible to prevent the thin metal outer cylinder 31 from being bent in a curved shape with an increase in the clamping force, and to prevent the center portion of the product sheet 28 from being thickened.

Further, by forming grooves 51 in the circumferential direction near the end of the thin metal outer cylinder 31 to reduce the thickness: t by the thickness reduction amount: h, the both ends of the thin metal outer cylinder 31 can be formed. By increasing the flexibility, it is possible to prevent the thin metal outer cylinder 31 from becoming drum-shaped with an increase in the clamping force, so that the non-uniform thickness portion at the end of the product sheet 28 is not compressed, In addition, end contact between the main roll 26 and the pressing roll 27 can be prevented.

[0037]

As described above, according to the first aspect of the present invention, the contact length with the main roll is determined by utilizing the elastic deformation of the thin metal outer cylinder in the same manner as in the rubber roll press forming method. Therefore, it is possible to manufacture a resin film / sheet excellent in optical quality without residual distortion and without irregular reflection of light or birefringence phenomenon. In addition, since both the front and back surfaces are pressed by the metal surface, the mirror surface and the embossed pattern can be transferred with high precision. Furthermore, since the metal inner cylinder is arranged inside the thin metal outer cylinder via the cooling fluid flow-in space, the strength of the holding roll can be secured while maintaining the flexibility of the thin metal outer cylinder. Furthermore, rapid cooling is possible by the thin metal outer cylinder having a small thickness, and it is possible to realize the production of a resin film / sheet that is thin and mirror-clear and has no residual distortion, which was impossible by the conventional method.

According to the second aspect of the present invention, by performing the crowning in which the outer diameter of the central portion is larger than the outer diameters of the both end portions, the pinching load is reduced due to the low flexibility of the end portions. As the size increases, the thin metal outer cylinder can be prevented from being deformed into a concave shape (hourglass shape), and the resin film / sheet can be prevented from being thickened at the center.

Further, according to the third aspect of the present invention, the thin-walled thick portion can improve the flexibility at both ends of the thin-walled metal outer cylinder. Deformation into a concave shape (hourglass shape) can be prevented, and thickening of the resin film / sheet at the center can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a roll showing an embodiment of a horizontal roll forming apparatus according to the present invention.

FIG. 2 is a longitudinal sectional view of the press roll.

FIG. 3 is a front view showing dimensions of the press roll.

FIG. 4 is an enlarged sectional view of a portion A shown in FIG.

FIG. 5 is an overall configuration diagram of a sheet / film extrusion forming apparatus including the horizontal roll forming apparatus.

FIG. 6 is a table comparing the flexibility of the press roll and a conventional rubber roll.

FIG. 7 is a graph showing a change in a displacement amount and a linear pressure with respect to a load caused by a groove of the holding roll.

FIG. 8 is a table showing the results of molding by the press roll and a conventional metal roll.

FIG. 9 is a table showing details of a holding roll and a metal roll used in the molding of FIG. 7;

FIG. 10 is a chart showing a result of molding the A-PET resin by the press roll.

FIG. 11 is an explanatory view showing a conventional metal roll pinching method.

FIG. 12 is an explanatory view showing a conventional rubber roll pinching method.

[Explanation of symbols]

 Reference Signs List 21 horizontal roll forming device 25 T die 26 main roll 27 holding roll 31 thin metal outer cylinder 32 cooling fluid 33 flow-in space 34 metal inner cylinder 41A, 41B rotation shaft 42A, 42B outer cylinder support flange 46 fluid shaft cylinder 47a, 47b Cylinder support flange 51 Groove C Crowning amount

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Sakuhiro Sakane 1-7-89 Minami Kohoku, Suminoe-ku, Osaka-shi, Osaka Inside Hitachi Zosen Corporation (72) Inventor Shinji Miyamoto Minami-Kohoku, Suminoe-ku, Osaka-shi, Osaka 1-7-89 Hitachi Zosen Corporation

Claims (3)

[Claims] 1. A sheet / film forming roll apparatus for introducing a sheet-like molten resin extruded from an extruder between a main roll and a holding roll to perform pressure forming, wherein the main roll is formed of a highly rigid metal. A high-rigidity metal inner cylinder which is constituted by a roll, and the holding roll is a thin metal outer cylinder having flexibility, and a cooling fluid flowing space is provided in the thin metal outer cylinder and coaxially fitted into the thin metal outer cylinder. The thickness of the thin metal outer cylinder / the roll radius ≦ 0.03. 2. The sheet / film forming roll device according to claim 1, wherein the holding roll is formed in a drum shape in which the outer diameter at the center of the thin metal outer cylinder is larger than the outer diameter at both ends. . 3. The sheet / film forming method according to claim 1, wherein thin portions having a reduced thickness are formed in the vicinity of both ends of the thin metal outer cylinder of the holding roll in the circumferential direction. Roll equipment.