JP2022071335A - Rubber roller for manufacturing plastic film, method and apparatus of manufacturing plastic film using the same - Google Patents

Abstract

To provide a rubber roller for manufacturing a plastic film, which is more unlikely to cause wrapping around a nip roller even in a high speed film manufacturing.SOLUTION: A rubber roller for manufacturing a plastic film is formed on an outer periphery of a core material, and has an elastic body layer formed of rubber. A heat transfer coefficient of the elastic body layer in a thickness direction is higher in an axial end portion of the core material than in an axial center portion of the core material.SELECTED DRAWING: Figure 1

Description

The present invention relates to a rubber roller for forming a film of a plastic film, a method for manufacturing a plastic film using the same, and a manufacturing apparatus.

Conventionally, as one of the methods for forming a plastic film, for example, as described in Patent Document 1, a melted resin extruded into a sheet is coated with silicone rubber on the surface of a core metal having a cooling function. A method is used in which the plastic is sandwiched between a rubber roller and a cooling roller to cool and solidify.

The reason for using the silicone rubber roller is that the silicone rubber has a high mold releasability with respect to the molten resin, it is easy to prevent the molten resin from adhering to the rubber roller and wrapping around, and even if it is heated from the molten resin, it is sufficient. This is because it can withstand long-term use due to its heat resistance.

International Publication No. 2013/08925

However, even if silicone rubber is used, if the film forming speed is increased to improve productivity, the temperature of the rubber roller surface rises, which causes a decrease in mold releasability, and the molten resin becomes a rubber roller. There was a problem that wrapping and film formation became impossible.

An object of the present invention is to provide a rubber roller for forming a plastic film, which can prevent wrapping of a molten resin even in forming a film at high speed, and a method and an apparatus for producing a plastic film using the same. There is something in it.

The rubber roller for forming a film of a plastic film of the present invention that solves the above problems is
It has a cylindrical core material and an elastic body layer formed on the outer circumference of the core material and made of rubber.
The elastic layer has a higher thermal conductivity in the thickness direction at the axial end portion than at the axial central portion of the core material.

Further, the rubber roller for forming a film of a plastic film of the present invention is a laminated body in which the elastic body layer is a laminated body in which two or more rubber layers including two or more types of rubber layers having different thermal conductivitys are laminated.
It is preferable that the thickness of the rubber layer having the highest thermal conductivity among the rubber layers gradually decreases from the axial end portion of the core material toward the axial central portion.

Further, in the rubber roller for forming a film of a plastic film of the present invention, it is preferable that the rubber layer having the lowest rubber hardness among the rubber layers is the rubber layer having the highest thermal conductivity.

Further, in the rubber roller for forming a film of a plastic film of the present invention, it is preferable that the rubber layer on the outermost surface of the elastic body layer has a rubber hardness of A80 or more.

Further, in the rubber roller for forming a film of a plastic film of the present invention, it is preferable that the rubber layer of the innermost layer of the elastic body layer has a tensile strength of 12 MPa or more.

In the method for producing a plastic film of the present invention, which solves the above problems, a molten resin is discharged from a T-die, and the discharged molten resin is cooled while being sandwiched between a nip roller and a cooling roller to solidify the molten resin. This is a method for manufacturing a plastic film to obtain a web-like plastic film.
The nip roller is the rubber roller for forming a film of a plastic film of the present invention.

The plastic film manufacturing apparatus of the present invention that solves the above problems includes a T-die, a nip roller, and a cooling roller.
A plastic film manufacturing apparatus in which a T-die, a nip roller, and a cooling roller are arranged so that the molten resin discharged from the T-die in a web shape is sandwiched between the nip roller and the cooling roller. ,
The nip roller is the rubber roller for forming a film of a plastic film of the present invention.

Each term in the present invention is defined as follows.
The "elastic body layer" is a layer made of an elastic body, and the elastic body is a substance generally called rubber or an elastomer, and is a polymer organic compound or a solid material containing the same as a basic component. It means the one defined in JIS K6200. For example, silicone rubber, Budadiene-acrylonitrile copolymer (NBR), polychloroprene (CR), chlorosulphonized polyethylene (CSM), ethylene-propylene copolymer, ethylene propylene diene rubber (EPDM), or weather resistance to them. Additives or formulations that improve slipperiness, wear resistance, strength, etc. are added.

The "thermal conductivity in the thickness direction" is the thermal conductivity in the thickness direction of the elastic body layer, in other words, the thermal conductivity in the radial direction of the rubber roller, and when the elastic body layer is composed of a plurality of rubber layers, the entire plurality of layers Refers to the thermal conductivity of.

"Rubber hardness" is an index indicating the hardness of rubber, and in the present invention, it refers to a measured value in a type A durometer hardness test shown by JIS K 6253: 2012.

The "nip roller" is a roller for sandwiching and cooling and solidifying a molten resin together with a "cooling roller", and refers to a roller having elasticity in the vicinity of the surface. For example, a roller having an ultra-smooth surface, a satin finish, or a special shape for the purpose of transferring the surface shape to the surface of a plastic film is also included. Further, the surface may have a metal thin film sleeve, a plating layer, or the like.

The "cooling roller" refers to a roller whose purpose is to solidify the molten resin by contacting and cooling the molten resin.

INDUSTRIAL APPLICABILITY The present invention provides a rubber roller for forming a plastic film film, which can prevent the molten resin from wrapping even in the film forming at a high speed, and a method and an apparatus for producing a plastic film using the same.

It is schematic cross-sectional view which shows one Embodiment of the rubber roller for film formation of a plastic film of this invention. It is a schematic side view which shows one Embodiment of the plastic film manufacturing apparatus of this invention. It is a schematic sectional drawing which shows another embodiment of the rubber roller for film formation of a plastic film of this invention. It is a schematic sectional drawing which shows another embodiment of the rubber roller for film formation of a plastic film of this invention. It is a schematic sectional drawing which shows the rubber roller for film formation of a conventional plastic film.

Hereinafter, an example of the best embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, in the plastic film film forming rubber roller (hereinafter, may be referred to as a rubber roller) 100 of the present invention, the core material 12 is coated with the elastic body layer 11.

The core material 12 has a structure capable of cooling the temperature of the surface of the rubber roller 100 from the inside, for example, as shown in FIG. 1, a flow path 13 for circulating a heat medium such as water is provided inside.

The material of the core material 12 is not particularly limited and can be appropriately selected from ordinary structural materials such as metal, plastic, and fiber reinforced resin, but a metal material having high thermal conductivity is preferably used from the viewpoint of cooling capacity. Can be done. As the metal material, for example, carbon steel, stainless steel, aluminum, an aluminum alloy, or the like can be preferably used.

In the rubber roller 100 of the present invention, the surface of the core material 12 is coated with the elastic body layer 11, and the thermal conductivity in the thickness direction of the elastic body layer 11 is the axial end portion of the core material 12 with respect to the axial central portion. Is high.

The present inventors have produced a plastic film (hereinafter, may be referred to as a film) 6 in which the molten resin 2 is sandwiched between the nip roller 3 and the cooling roller 4 as shown in FIG. 2 and cooled and solidified. It was found that the major factor hindering the improvement of the film speed was the wrapping of the molten resin 2 around the nip roller 3 due to the adhesion of the molten resin 2, and that this occurred from the end of the nip roller 3. As a result of diligent studies based on this knowledge, the thermal conductivity in the thickness direction of the elastic body layer 11 of the rubber roller 100 used as the nip roller 3 is higher at the axial end portion than at the axial center portion of the core material 12. By doing so, it was found that it is possible to prevent the above wrapping. Since the thermal conductivity in the thickness direction of the elastic body layer 11 is higher at the axial end portion than at the axial central portion of the core material 12, the surface temperature of the end portion of the rubber roller 100 is efficiently lowered. As a result, the releasability between the end portion of the rubber roller 100 and the molten resin 2 is improved, and it is possible to prevent adhesion and wrapping starting from the end portion. Further, since the surface shape of the rubber normally used for the surface of the elastic body layer 11 of the nip roller 3 is transferred to the plastic film 6, the composition cannot be easily changed, and the thermal conductivity is controlled. However, according to the present invention, the film forming speed can be easily improved by adjusting only the composition of the rubber layer in contact with the film edge portion 23 at the end portion which is not a product and improving the thermal conductivity. Can be made to.

The method for increasing the thermal conductivity of the elastic layer 11 of the rubber roller 100 in the thickness direction at the axial end portion higher than the axial central portion of the core material 12 is not particularly limited, but as shown in FIG. 1, for example. The elastic layer 11 may be divided into a plurality of portions in the axial direction, and a rubber 16 having a high thermal conductivity may be provided at the ends. Further, as shown in FIG. 3, the elastic body layer 11 is composed of a plurality of rubber layers having different thermal conductivitys, and the thickness of the rubber layer 17 having the highest thermal conductivity is from the axial end portion to the central portion. It may be gradually reduced, and in this case, since there is no seam, no seam mark remains on the formed plastic film 6, which is preferable.

Further, as shown in FIG. 3, the elastic body layer 11 is composed of a plurality of rubber layers having different thermal conductivitys, and the thickness of the rubber layer 17 having the highest thermal conductivity gradually decreases from the axial end portion to the central portion. In this case, it is preferable that the rubber layer having the lowest rubber hardness among the rubber layers is the rubber layer 17 having the highest thermal conductivity. With such a structure, it becomes easy to make the contact pressure distribution in the axial direction of the nip roller 3 and the cooling roller 4 uniform. If the contact pressure distribution in the axial direction is uniform, for example, in a plastic film forming method for transferring the surface shape of the nip roller 3 and / and the cooling roller 4 to the film 6, uniform transfer over the entire width is possible. can get.

Further, it is preferable that the rubber layer 18 on the outermost surface of the elastic body layer 11 has a rubber hardness of A80 or more. In the method of forming a film of a plastic film in which the molten resin 2 is sandwiched between the nip roller 3 and the cooling roller 4 and cooled and solidified, the resin contained in the molten resin 2 called fisheye (hereinafter, may be referred to as FE) is deteriorated. It is known that there is an effect of crushing protrusions due to an object or the like, and it is also known that the higher the rubber hardness of the elastic body layer 11 of the nip roller 3, the higher the crushing effect. For example, when the film 6 is used as the surface protective film, the FE may cause a problem that a dent is generated on the protecting partner. On the other hand, if the rubber hardness of the elastic layer 11 is too high, the rubber is less likely to be deformed, which not only deteriorates the contact pressure distribution in the roller axial direction, but also deteriorates the contact width between the nip roller 3 and the cooling roller 4 in the rotational direction. Due to the narrowing (hereinafter, referred to as the nip width), it is not possible to sufficiently obtain the contact time between the nip roller 3 and the molten resin 2, and the surface of the nip roller 3 is insufficiently cooled or shaped. It may not be possible to transfer the shape to the film 6. In response to this problem, the inventors have found that when the elastic layer 11 is composed of a plurality of rubber layers, the FE can be effectively crushed as long as the outermost rubber has a high hardness of A80 or higher. rice field. That is, by making the rubber layer 17 on the inner layer side soft rubber, the elastic body layer 11 becomes flexible as a whole, and the FE is obtained while maintaining a good contact pressure distribution in the roller axial direction and obtaining a sufficient nip width. It becomes possible to be compatible with the crushing action. For the above reasons, the rubber hardness of the rubber layer 17 on the inner layer side of the elastic layer 11 is preferably A60 or less.

Further, when the elastic body layer 11 is composed of a plurality of rubber layers as shown in FIG. 4, the rubber layer 19 of the innermost layer preferably has a tensile strength of 12 MPa or more. The nip roller 3 for film forming is often used at a high contact pressure, and the rubber may be broken. Destruction of rubber is particularly likely to occur in the innermost layer, but if the tensile strength of the rubber in the innermost layer is 12 MPa or more, it is easy to obtain a practically sufficient life even if a sufficient contact pressure is applied in this application.

The rubber used for the rubber layer of the elastic layer 11 is, for example, silicone rubber, budaziene-acrylonitrile copolymer (NBR), polychloroprene (CR), chlorosulphonized polyethylene (CSM), ethylene / propylene copolymer, ethylene propylene diene. Rubber (EPDM), or an additive that improves weather resistance, slipperiness, abrasion resistance, strength, etc., can be added to them, or a formulation can be appropriately selected and used. For example, a silicone rubber having high mold releasability and heat resistance to the molten resin 2 can be preferably used for the rubber layer in contact with the molten resin 2. On the other hand, as the rubber near the interface with the core material 12, it is preferable to use rubber having a tensile strength of 12 MPa or more as described above, but it is often difficult to obtain sufficient strength with silicone rubber. When the elastic body layer 11 is composed of a plurality of rubber layers, the rubber of the innermost layer is cooled by the cooling structure of the core material, so that heat resistance is not required in many cases, and the outermost layer is releasable. A structure in which silicone rubber having excellent heat resistance is used and other rubber having excellent strength, such as NBR or urethane rubber, is used for the innermost layer can be preferably used.

Further, the surface of the rubber roller 100 may be provided with a material other than rubber, for example, a thin film sleeve made of metal, a fluorine tube, or the like. As the thin film sleeve made of metal, one made of nickel or stainless steel, or one having various surface treatments such as plating or coating on the surface thereof can be used.

As a method of coating the surface of the core material 12 with the rubber layer 11, a method of winding a sheet-shaped uncrosslinked rubber for cross-linking, a method of applying liquid uncross-linked rubber, or a method of coating the surface of the core material 12 is performed, as in the case of manufacturing various rubber rollers. There is a method of spraying or filling in a mold and then cross-linking, and a method of inserting a core material 12 into a cross-linked rubber tube and adhering it.

The thickness of the elastic layer 11 is not particularly limited, but it is preferably covered with rubber having a thickness of about 1 to 20 mm. Further, in the configuration in which the rubber layers are laminated as illustrated above, it is preferable that the above range is taken by the entire laminated rubber. Within this range, when the film 6 is formed, it is easy to alleviate the non-uniformity of the contact pressure due to the processing accuracy of the rubber roller 100 and the opposing cooling roller 4 and the uneven thickness of the film 6 in the width direction, and the film 6 is uniformly melted. The resin 2 can be easily pressed and cooled. Further, when the temperature of the surface of the embossed roller is controlled by a structure such as circulating a heat medium inside the core material 12, it becomes easy to control the temperature.

FIG. 2 shows an example of the form of the plastic film manufacturing apparatus of the present invention. In the form of the plastic film manufacturing apparatus of the present invention, the molten resin 2 discharged from the T die 1 is sandwiched and cooled by the cooling roller 4 and the nip roller 3 to obtain the plastic film 6. Then, if necessary, cutting or trimming of the edge 23 is performed in the slit step 21, and the film roll 10 is wound into a roll in the winding step 22. After that, if necessary, it is subjected to a slitting process and other processing processes again to become a product roll.

The T-die 1 is melt-kneaded by an extruder (not shown), and the sent molten resin 2 is continuously discharged from a slit provided in the depth direction with respect to the drawing to extrude the molten resin 2 into a sheet shape. It is preferable to provide a filtration device called a polymer filter between the extruder and the T-die 1 because it is easy to reduce the mixing of foreign substances called fisheye and deteriorated resin. The width of the slit of the T-die 2 is preferably adjustable at regular intervals in the width direction of the film 6 and controls the thickness unevenness in the width direction of the film 6. The thickness of the film 6 to be formed can be adjusted by the ratio of the discharge speed of the molten resin 2 to the rotation speed of the cooling roller 4. When the film 6 to be formed has a multi-layer structure, a molten resin laminating device called a feed block is provided upstream of the T-die 1, or the T-die 1 has a structure having a plurality of manifolds called a multi-manifold structure. It is possible to obtain a multilayer film by extrusion. Further, the width of the film 6 to be formed may be changed by restricting the flow path width of the molten resin 2 in the film width direction.

The positional relationship between the T-die 1 and the cooling roller 2 and the nip roller 3 is preferably an adjustable structure. Normally, in order to transfer the surface shape of the nip roller 3 to the molten resin 2 with high accuracy, it is preferable to hold the molten resin 2 in the molten state before cooling. Therefore, as shown in FIG. 2, the molten resin 2 is directly connected to the nip point. It is preferable to adjust the position of the T-die 1 or the cooling roller 4 so that The positional relationship between the 4 and the nip roller 3 may be adjusted as appropriate.

The temperature of the molten resin 2 is appropriately set depending on the type of resin used and the film forming speed, but for example, in the case of a general polyethylene resin, it can be generally selected in the range of about 130 ° C. to 300 ° C.

As the cooling roller 4, for example, a cooling roller 4 having a flow path for circulating a heat medium inside and having a structure capable of controlling the surface temperature is used. The surface temperature of the cooling roller 4 is appropriately set depending on the type of the molten resin 2, the contact time between the molten resin 2 and the cooling roller 4, the room temperature and the humidity, and is 10 to 60 from the viewpoint of the film forming speed and the surface quality of the film. It is preferably ° C. When the temperature of the surface of the cooling roller 4 is within the above range, it is easy to cool and solidify the molten resin 2 within a practical film forming speed range, and on the surface of the cooling roller 4 during film forming. It also becomes easy to prevent deterioration of the surface quality of the film 6 due to the occurrence of dew condensation.

The material of the surface of the cooling roller 4 is not particularly limited, but a metal or ceramics or a resin and a composite film of resin and metal, and a carbon-based film such as diamond-like carbon can be used. It is also possible to use rubber as the surface material of the cooling roller 4. As the metal, iron, steel, stainless steel, aluminum, titanium, chromium, nickel and the like can be preferably used. Further, as the ceramic, a sintered body such as alumina, silicon carbide, or silicon nitride can be preferably used. Since the surface shape of the cooling roller 4 is transferred to the molten resin and becomes the surface shape opposite to the surface of the film 6 in contact with the nip roller 3, it is also possible to prevent deterioration of the appearance quality of the film 6 and the occurrence of convex defects. It is preferable to use industrial chrome plating or ceramics having excellent durability and rust prevention. In order to make the surface of the cooling roller 4 metal, known surface treatment techniques such as electroplating and electroless plating can be appropriately used in addition to the usual machining using a metal material. Similarly, in order to obtain a ceramic surface, known surface treatment techniques such as thermal spraying and coating can be appropriately used in addition to normal machining using a ceramic material.

The surface shape of the cooling roller 4 is transferred to the molten resin 2 to determine the shape of the opposite surface of the film 6 in contact with the nip roller 3. Therefore, the surface shape of the cooling roller 4 is appropriately designed according to the film 6 manufactured by using the plastic film manufacturing apparatus of the present invention.

The nip roller 3 is the rubber roller 100 for forming a film of a plastic film of the present invention. As described above, since the rubber roller 100 for forming a film of a plastic film of the present invention can prevent wrapping due to the adhesion of the molten resin, it is possible to form a film of a plastic film at high speed.

As a means for pressing the nip roller 3 against the cooling roller 4 and pressing the molten resin 2, the gap between the cooling roller 2 and the nip roller 3 or the pushing amount of the nip roller 3, that is, the relative position between the nip roller 3 and the cooling roller 4 May be controlled by a method of sandwiching a taper block or the like, or a method of controlling the force for pressing the nip roller 3 by an air cylinder or the like may be used. However, when forming a thin film such that the thickness of the molten resin 2 at the nip point is 100 μm or less, or when the rubber hardness of the elastomer coated on the nip roller 3 is 90 A or more, control by the pushing amount is not possible. Since the pressure spots may become too large, a method of controlling the pressing force is preferable. The pressing pressure is appropriately set, but is preferably in the range of about 0.1 to 5 kN / m. When the pressing pressure is in the above range, the surface of the nip roller 3 is easily transferred to the molten resin 2 and the FE is easily crushed.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. In addition, various evaluation and measurement methods are shown below.

[Thermal conductivity in the thickness direction of the elastic layer]
A sample was prepared from the same rubber as that coated on the roller, and the measurement was performed by the hot wire method using a test device compliant with JIS R 2616: 2001. For an elastic layer composed of a plurality of rubber layers, the thermal conductivity of each of the constituent rubbers is measured, the value obtained by multiplying each thermal conductivity by the thickness of each layer is integrated, and the total thickness of the elastic layer is divided. The heat conductivity of the elastic layer was taken as the heat conductivity.

[Rubber hardness]
A plate-shaped sample having a thickness of 15 mm was prepared from the same rubber as that coated on the roller, and measured at room temperature of 23 ° C. using a type A durometer conforming to JIS K 6253: 2012 at a standard measurement time.

[Tensile strength]
Measurement was performed using a dumbbell-shaped No. 3 test piece made of the same rubber as that coated on the roller by a measuring method and measuring device conforming to JIS K 6251: 2017.

[Film formation speed]
The film forming speed of the plastic film was gradually increased, and the molten resin was wrapped around the nip roller to make the film forming impossible.

[Transfer unevenness]
The haze of the obtained plastic film was measured at 5 points at equal intervals in the width direction using a measuring device and measuring method based on JIS K7136: 2000, and the difference between the maximum and minimum values divided by the average value was multiplied by 100. The value was taken as transfer unevenness.

[Height of FE]
The surface of the obtained plastic film was visually observed, and the height of the found FE was measured with a laser microscope. Five FEs were measured for each level and the average value was calculated.

[Example 1]
A roller having the structure shown in FIG. 1 was manufactured. Silicone rubber with a rubber hardness of A70 and a thermal conductivity of 0.35 W / mK is used for the elastic layer in the center, and silicone rubber with a rubber hardness of A70 and a thermal conductivity of 0.7 W / mK is used for the elastic layer at the ends. Both were coated with only one layer with a thickness of 10 mm. The width of the elastic layer at the center was 1500 mm, and the width of the elastic layer at the ends was 150 mm. The obtained rubber roller is used as a nip roller in a plastic film manufacturing apparatus in FIG. 2, and a single layer of low-density polyethylene (LDPE) having a density of 0.93 g / cm3 is applied from a T-die whose slit width is adjusted to 0.9 mm. In the configuration, the film was discharged at 220 ° C., sandwiched and cooled by a cooling roller and a nip roller to obtain a plastic film having a thickness of 30 μm.

[Example 2]
A roller having a two-layer rubber structure shown in FIG. 3 was manufactured. The elastic layer is covered with silicone rubber having a rubber hardness of A70 in both the surface layer and the inner layer to a thickness of 10 mm, and the rubber layer of the inner layer is made of rubber having a higher thermal conductivity than the rubber layer of the surface layer. The thermal conductivity in the thickness direction was 0.41 W / mK at the center in the roller axial direction and 0.65 W / mK at the end. The width of the elastic layer was 1800 mm. Using the obtained rubber roller as a nip roller, a film was formed under the same plastic film manufacturing apparatus and film forming conditions as in Example 1 to obtain a plastic film having a thickness of 30 μm.

[Example 3]
A roller having a two-layer rubber structure shown in FIG. 3 was manufactured. The elastic layer is covered with silicone rubber with a rubber hardness of A82 on the surface and silicone rubber with a rubber hardness of A55 on the inner layer to a thickness of 10 mm, and the rubber layer on the inner layer has higher thermal conductivity than the rubber layer on the surface. Using rubber, the thermal conductivity in the thickness direction of the elastic body layer was 0.38 W / mK at the central portion in the roller axial direction and 0.64 W / mK at the outermost portion. The width of the elastic layer was 1800 mm. Using the obtained rubber roller as a nip roller, a film was formed under the same plastic film manufacturing apparatus and film forming conditions as in Example 1 to obtain a plastic film having a thickness of 30 μm.

[Example 4]
A roller having a three-layer rubber structure shown in FIG. 4 was manufactured. The elastic layer is coated with silicone rubber with a rubber hardness of A70 for both the surface layer and the middle layer, the inner layer is coated with NBR with a rubber hardness of A70, and the rubber layer with the middle layer is the rubber with the highest thermal conductivity among the three layers. board. Further, the NBR of the inner layer had a tensile strength of 12.5 MPa. The thermal conductivity in the thickness direction of the elastic layer was 0.38 W / mK at the center in the roller axial direction and 0.61 W / mK at the end. The width of the elastic layer was 1800 mm. Using the obtained rubber roller as a nip roller, a film was formed under the same plastic film manufacturing apparatus and film forming conditions as in Example 1 to obtain a plastic film having a thickness of 30 μm.

[Comparative Example 1]
A roller having the structure shown in FIG. 5 was manufactured. The elastic layer was coated with a silicone rubber having a rubber hardness of A70 and a thermal conductivity of 0.35 W / mK with a thickness of 10 mm and only one layer. The width of the elastic layer was 1800 mm. Using the obtained rubber roller as a nip roller, a film was formed under the same plastic film manufacturing apparatus and film forming conditions as in Example 1 to obtain a plastic film having a thickness of 30 μm.

Table 1 shows the film forming results of the plastic films of Examples 1 to 4 and Comparative Example 1. In Comparative Example 1, the molten resin was wound around the nip roller at a film forming speed of 83 m / min. On the other hand, in Examples 1 to 4, winding did not occur even at 120 m / min.

Further, in Example 1, marks of rubber seams could be seen on the formed plastic film, but in Examples 2 to 4, since the elastic layer was not divided in the width direction, the marks of rubber seams could be confirmed. There wasn't.

In Example 3, since the rubber hardness of the rubber layer having the lowest rubber hardness is A55, the transfer unevenness is smaller than that of the other Examples and Comparative Examples, and the rubber hardness of the outermost rubber layer is A82. Therefore, the height of FE was lowered by about 40 to 50%.

The rubber of Example 2 broke and peeled off in about 1200 hours of use, whereas in Example 4, the tensile strength of the rubber layer of the innermost layer was 12.5 MPa, so that the rubber did not peel off even in 4000 hours.

The present invention is not limited to the plastic film manufacturing apparatus and manufacturing method, but is not limited to a laminating apparatus and process in which a molten resin is discharged onto a plastic film and sandwiched and cooled by two rollers, or embossing as a secondary processing, for example. It can be applied to devices and processes that heat a plastic film and nip it with a roller, such as processing, but the scope of its application is not limited to these.

1 T-die 2 Molten resin 3 Nip roller 4 Cooling roller 5 Peeling roller 6 Plastic film 7 Cutter 8 Edge suction tube 9 Near roller 10 Film roll 11 Elastic body layer 12 Core material 13 Heat medium flow path 14 Bearing 15 Central rubber 16 Rubber at the end 17 Rubber layer with the highest thermal conductivity 18 Rubber layer on the outermost layer 19 Rubber layer on the innermost layer 21 Slit process 22 Winding process 23 Film edge 100 Plastic film film-forming rubber roller 101 of the present invention Conventional Rubber roller for film formation of plastic film A Film traveling direction

Claims (7)

It has a cylindrical core material and an elastic body layer formed on the outer circumference of the core material and made of rubber.
The elastic layer has a higher thermal conductivity in the thickness direction at the axial end portion than at the axial central portion of the core material.
Rubber roller for film formation of plastic film. The elastic layer is a laminated body in which two or more rubber layers including two or more types of rubber layers having different thermal conductivitys are laminated.
The thickness of the rubber layer having the highest thermal conductivity among the rubber layers gradually decreases from the axial end portion of the core material toward the axial central portion.
The rubber roller for forming a film of a plastic film according to claim 1. The rubber roller for forming a film of a plastic film according to claim 2, wherein the rubber layer having the lowest rubber hardness among the rubber layers is the rubber layer having the highest thermal conductivity. The rubber layer on the outermost surface of the elastic body layer is a rubber roller for forming a film of a plastic film according to claim 2 or 3, wherein the rubber layer has a rubber hardness of A80 or more. The rubber layer for forming a film of a plastic film according to any one of claims 2 to 4, wherein the rubber layer of the innermost layer of the elastic body layer has a tensile strength of 12 MPa or more. A method for manufacturing a plastic film obtained by discharging a molten resin from a T-die and solidifying the molten resin by cooling the discharged molten resin while sandwiching it between a nip roller and a cooling roller to obtain a web-shaped plastic film. There,
The nip roller is a rubber roller for forming a film of a plastic film according to any one of claims 1 to 5.
How to make a plastic film. Equipped with T-die, nip roller and cooling roller
A plastic film manufacturing apparatus in which a T-die, a nip roller, and a cooling roller are arranged so that the molten resin discharged from the T-die in a web shape is sandwiched between the nip roller and the cooling roller. ,
The nip roller is a rubber roller for forming a film of a plastic film according to any one of claims 1 to 5.
Plastic film manufacturing equipment.

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