JP2001300957A - Method for manufacturing film by calender molding of polyolefin resin and calender apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a calender apparatus and method capable of manufacturing a polyolefin resin film having a smooth surface by calender molding. SOLUTION: In the method for manufacturing the polyolefin resin film by calender molding, a difference between the surface temperature on the atmosphere side of the resin sheet on the inlet side on the roll of the final stage and the surface temperature on the role side of the resin sheet on the outlet side of the roll of the final stage is held to 10 deg.C or lower. Further, in the calender apparatus for molding the polyolefin resin film, temperature reserving devices 14 are respectively attached at least not only on the inlet and outlet sides of the roll 4 of the final stage but also on the inlet side of the roll immediately before the final stage so that the heat reflecting surfaces 19 or heating surfaces of them are arranged along the peripheral surfaces of the rolls so as to leave an interval with respect to the rolls to hold the difference between the surface temperature on the atmosphere side of the resin sheet on the inlet side of the roll of the final stage and the surface temperature on the role side of the resin sheet on the outlet side of the roll of the final stage is held to 10 deg.C or lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a film by calendering a polyolefin resin and a calender for the same, and more particularly, to rolling a polyolefin resin containing an olefin-based thermoplastic elastomer (TPO) with a calender. In addition, the present invention relates to a method for producing a polyolefin resin film capable of stably obtaining a film having a smooth surface, and a calender device therefor.

[0002]

2. Description of the Related Art Polyolefin resins have been widely used in various fields since they are inexpensive and have excellent mechanical and chemical properties. From the viewpoint of environmental protection called "chlorine", it is attracting attention as an alternative to polyvinyl chloride resin. Among the polyolefin resins, in particular, polyethylene and polypropylene are considered to be promising alternative materials in consideration of economy and safety.

[0003] Among them, sheets and films made of polyethylene resin are widely used in various fields. For example, it is widely used as a film for building materials, a film for decorative display, a medical film such as a bandage, a film for a decorative material, an adhesive tape, a film for agriculture, and the like. Sheets and films made of such polyethylene resins are conventionally and usually produced by extrusion or inflation molding, while production of films by calendering is generally more difficult than vinyl chloride resins. In some cases, a thick sheet having a thickness of about 200 μm is only industrially manufactured by calendering.

[0004] However, as is well known,
In particular, calendering, which is widely used for the processing of vinyl chloride resin, is easier to change steps, has less material loss, and is relatively easy to change conditions during operation, as compared to extrusion or inflation molding. The advantage is that the production speed is very fast.

[0005] In recent years, attempts have been made to produce films and sheets by calender molding of polyolefin resins. However, polyolefin resins generally have a low viscosity at the time of melting, and therefore, are often used for calender molding. Adheres to the roll, so-called "rolled"
(A defect that the film cannot be pulled off (peeled off) from the final roll of the calendering device) or drawdown from the calendering roll easily occurs. Further, in many cases, the film is easily broken during stretching. Thus, conventionally, it is extremely difficult to obtain a film having a smooth surface stably by calender molding of a polyolefin resin.

As described above, when the surface of the film is not smooth, when printing is performed on the film, so-called ink loss or the like occurs, which causes a defect in the product.

Furthermore, recently, not only polyolefin resins, but also so-called olefin-based thermoplastic elastomers (TPO)
In place of conventional vinyl chloride resin, in the field of medical tapes such as bandages and plasters, display tapes, bundling, anticorrosion, insulation, protection, masking, etc. There is a desire for molded products.

As such an olefin-based thermoplastic elastomer, for example, a block or graft copolymer having a polypropylene and (in some cases, polybutene) an ethylene-propylene copolymer component, a so-called reactor TPO, is known. As the reactor TPO, for example, "Cataroy" of Montell Co., "PER" of Tokuyama Corporation, "Newcon" of Chisso Corporation, and the like are known.

[0009] However, even with olefin-based thermoplastic elastomers, a method of obtaining a smooth and beautiful film having a surface of not citron skin by calendering has not been known as a practical problem.

More specifically, in order to calender-mold a polyolefin resin, necessary additives such as an antioxidant and a lubricant are added to the polyolefin resin, kneaded in a closed kneader, and then passed through a heating roll. It is heated by a strainer and supplied to a calender roll to form a film.

The behavior of the resin composition on a calender roll will be described with reference to the most common inverted L-type four calender shown in FIGS. 1 and 2 as an example. The material (polyolefin resin composition) supplied between the first bank 5 and the second bank 5)
The bank 6 is sheared, generates heat, is formed into a sheet, and is transported along the second roll 2 and the third roll 3 to form the second bank 6 and the third bank 7, respectively. After being rolled between the roll 3 and the fourth roll 4 (final roll) and carried on the fourth roll, the roll is taken up by the take-up roll 8 and, if necessary, embossed by the embossing device 9. Cooling device 1 having a plurality of cooling rolls
After cooling at 0, it is taken up by the take-up device 11.

As shown in FIG. 2, in such a calendering process, in particular, the third roll 3 is formed on the delivery side 3R _{o of} the third roll where the material (ie, polyolefin resin sheet) is taken up by the fourth roll 4. , And the fourth roll 4
At the outlet side 4R _o of the fourth roll after the material has been taken up by the take-up roll 8, each of which comes into contact with the outside air, the temperature is significantly reduced, and in extreme cases, the inlet side 4R of the fourth roll The surface temperature of the material that comes into contact with the outside air of the material _i is the second
In some cases, the temperature may drop by about 30 ° C. as compared with the resin of the bank 6. When the polyolefin resin is the temperature of the surface of the material in contact with the outside air thus in the fourth inlet side 4R _i roll 4 is reduced, occurs a minute crystal of the polyolefin resin to the surface of the sheet, it is drawn off from the last stage rolls 4 The surface of the film 12 becomes yuzu skin, and even after the subsequent steps, ie, embossing, cooling, and winding, the yuzu skin is maintained, and thus a film having a smooth surface cannot be obtained.

[0013]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the production of a film by calendering a polyolefin resin.
An object of the present invention is to provide a calender and a calender capable of obtaining a polyolefin resin film having a smooth surface by calendering.

[0014]

According to the present invention, there is provided a method for producing a film by calendering a polyolefin resin. A method for producing a film by calendering a polyolefin resin, wherein a difference between the surface temperature of the resin sheet on the exit side from the roll and the surface temperature on the roll side is maintained at 10 ° C. or less.

Further, according to the present invention, the difference between the surface temperature on the atmosphere side of the resin sheet on the entry side on the last stage roll and the surface temperature on the roll side of the resin sheet on the exit side from the last stage roll is determined. In order to maintain the temperature at 10 ° C. or less, a heat reflection surface or a heating surface is provided at least on the entrance side and the exit side of the roll of the last stage and the entrance side of the roll immediately before the last stage with a space around the roll. A calender device for molding a polyolefin resin, characterized in that a heat retaining device is attached along the surface.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, as shown in FIG. 2, the entry side R _i of each roll is formed by rolling the material by a nip between the rolls, and forming a sheet as a next roll (or pull). refers to about half of the surface up to the previous carried to take roll) roll, and the exit side R _o of the roll, material is taken up in the next stage of the roll (or take-up roll),
As such, it refers to approximately the half-peripheral surface of the preceding roll that is exposed to the outside air.

In the present invention, the polyolefin resin comprises:
refers to a homo- or copolymer of α-olefin, preferably, polyethylene, polypropylene, ethylene-propylene copolymer, other than ethylene-butylene copolymer, and the like,
The olefin-based thermoplastic elastomer (T
PO).

Further, in the present invention, the roll configuration of the calendering apparatus includes three upright types, four upright types, four L-types,
Any of the inverted L-type, the Z-type four-type, the six-type, etc. may be used, but the following description will be made by taking the representative example of the inverted L-type four as shown in FIG.

As described above, in the production of a film by calender molding of a polyolefin resin, the temperature of the material is remarkably lowered while being transported through the third roll and the fourth roll. As shown in the figure, at least the entry side 4R of the fourth roll (final stage roll) 4
_i and the egress 4R _o fourth roll immediately preceding the roll of Toko (third
At each of the entrances 3R _i of the roll 3, the heat retaining device 14 is installed such that the heat reflection surface 19 or the heating surface is spaced close to and close to the surface of the roll, and the entrance on the fourth roll 4. the difference 10 ° C. to the exit side 4R _o of the roll side of the surface temperature of the material from 4R _i surface temperature of the fourth roll 4 material outside air side of the following, preferably, while maintaining the 8 ° C. or less, fourth By taking the film 15 from the roll, the crystallization of the polyolefin resin on the fourth roll can be prevented, and a film having a stable and smooth surface can be obtained.

As an example of the heat retaining device 14 used in the present invention, as shown in FIG. 3, for example, a heat insulating material layer 17 such as glass fiber is provided on a substrate 16 and an aluminum mirror surface foil such as an aluminum mirror foil is provided thereon. Metal sheet 18 with high heat reflectance
As a heat reflecting surface 19. The heat reflection surface has a surface shape to cover along and along the peripheral surface of the roll on the entrance side or the exit side of the roll. The heat reflecting surface is preferably closer to the material (sheet) on the roll.

Although not shown, the heat retaining device may have a structure in which an appropriate heat medium, for example, a heating steam or a heating oil is circulated, or may have a structure in which a heater is incorporated. However, in any case, the surface, that is, the heating surface needs to have a shape along the roll peripheral surface.

[0022]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited by these examples.

EXAMPLE 1 As shown in FIG. 3, a heat reflecting surface made of an aluminum mirror-finished foil was rolled on the entrance side of the third roll and the entrance side and exit side of the fourth roll of the inverted L-type four-roll calendering apparatus. The heat reflecting plate provided opposite to the roll is installed close to the sheet (material) on the roll (this is referred to as a mounting type A of the heat reflecting plate), and a high-density polyethylene compound having the following composition is calendered. Thus, a film having a thickness of 30 μm was manufactured.

High-density polyethylene resin compound High-density polyethylene (Novatec HD HB430 manufactured by Nippon Polychem Co., Ltd., MFR = 0.30 g / 10 minutes) 100 parts by weight Antioxidant (Irganox 1010 manufactured by Nippon Ciba Geigy Co., Ltd.) 0.2 parts by weight Lubricant (calcium stearate) 0.1 parts by weight Pigment (titanium oxide) 10 parts by weight The conditions for calendering are as follows: the temperature of the material supplied to the calendering device is 160 ° C. Roll temperature 170 ° C, peripheral speed of the fourth roll 10 to 30
m / min, and the third roll / fourth roll peripheral speed ratio was 1/17.

The second bank temperature (T _b ), the surface temperature (T _i ) of the material on the atmosphere side of the fourth roll entering side, and the roll side temperature (T _o ) of the material on the fourth roll exit side were obtained. Table 1 shows the results of the determination of the surface properties of the resin film. The surface temperature of each material was measured with a non-contact radiation thermometer (manufactured by Tasco Japan Co., Ltd.). The surface properties of the obtained film were evaluated as "O" when the surface was smooth, "A" when the skin was slightly, but slightly, and "X" when the surface was almost yuzu.

Similarly, the installation type B in which the heat reflecting plate is installed on the entrance side of the third roll, the entrance side and the exit side of the fourth roll of the calender device, the exit side of the first roll and the exit side of the second roll. Mounting type C in which a heat reflection plate is installed on the side, the entrance side of the third roll, the entrance side, the entrance side and the exit side of the fourth roll, and the installation type D in which the heat reflection plate is installed only on the entrance side of the fourth roll. A film having a thickness of 30 μm made of the same high-density polyethylene resin as described above was produced. In addition, without installing a heat reflecting plate on the calender, similarly, a thickness 3 made of the same high-density polyethylene resin as described above.
A 0 μm film was produced. Table 1 shows the determination results of the second bank temperature, the surface temperature of the material on the atmosphere side of the fourth roll entering side, the roll side temperature of the material on the fourth roll exit side, and the surface properties of the obtained resin film.

[0027]

[Table 1]

Example 2 A 30 μm thick film was produced in the same manner as in Example 1 except that the following polypropylene resin compound was used instead of the high-density polyethylene resin compound. The second bank temperature, the surface temperature of the material on the atmosphere side of the fourth roll entering side, the fourth
Table 2 shows the results of determining the roll-side temperature of the material on the roll exit side and the surface properties of the obtained resin film.

High-density polypropylene resin composition High-density polypropylene (Jiaromer PM620A manufactured by Japan Polyolefin Co., Ltd., MFR = 7 g / 10 min) 100 parts by weight Antioxidant (Irganox 1010 manufactured by Nippon Ciba Geigy Co., Ltd.) 0.2 Parts by weight Lubricant (calcium stearate) 0.1 part by weight Pigment (titanium oxide) 10 parts by weight

[0030]

[Table 2]

[0031]

As described above, according to the present invention, when a film is produced by calender molding a polyolefin resin, the surface temperature of the resin composition on the entry side on the roll at the final stage and the surface temperature of the final stage are reduced. A film having a smooth surface without causing citron skin by maintaining the difference between the surface temperature of the resin composition on the exit side from the roll and the roll side of the resin composition at 10 ° C. or lower, preferably 8 ° C. or lower. Can be obtained stably.

Further, according to the present invention, at least a heat reflection surface or a heating surface is provided at intervals on at least the entrance side and the exit side of the last stage roll and the entrance side of the roll immediately before the last stage. The method according to the present invention can be advantageously carried out by using a calender device having a heat retaining device mounted along the peripheral surface of the device.

[Brief description of the drawings]

FIG. 1 is a schematic device configuration diagram showing an entire calendar device.

FIG. 2 is a diagram showing a configuration of an inverted L-type four rolls in a calendar device.

FIG. 3 is a sectional view showing one embodiment of a heat reflection plate used in the present invention.

[Explanation of symbols]

1 ... the first roll 2 ... the second roll 3 ... the third roll 4 ... fourth roll 5 ... the first bank 6 ... the second bank 7 ... the third bank 8 ... the take-up roll R _i ... roll of the incoming side R _o ... Outgoing side of roll 14 ... Insulation device 16 ... Substrate 17 ... Heat insulation layer 19 ... Heat reflection surface 19 ... Heat reflection surface

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) C08L 23:00 C08L 23:00

Claims (2)

[Claims] 1. A method for producing a film by calendering a polyolefin resin, wherein the surface temperature of the air side of the resin sheet on the entrance side on the roll at the final stage and the roll of the resin sheet on the exit side from the roll at the final stage. A method for producing a film by calendering a polyolefin resin, wherein the difference from the surface temperature on the side is maintained at 10 ° C. or less. 2. The difference between the surface temperature on the atmosphere side of the resin sheet on the entry side on the last roll and the surface temperature on the roll side of the resin sheet on the exit side from the last roll is maintained at 10 ° C. or less. In this way, at least on the entry side and exit side of the last stage roll and on the entry side of the roll immediately before this last stage, a heat reflection surface or a heating surface is spaced apart and kept warm along the peripheral surface of the roll. A calender device for molding polyolefin resin, which is provided with a device.