JPH0788928A - Thermoplastic resin sheet or film manufacturing apparatus - Google Patents

Abstract

PURPOSE:To prevent the abrasion-damage of the outer peripheral surface of a casting drum caused by an endless metal belt by supporting the endless metal belt only on both sides of the casting drum in a contact state when the supply of a molten resin from a T-die is interrupted during the molding of a sheet or film by the abnormality of an extruder or power failure. CONSTITUTION:The film like thermoplastic resin extruded from a T-die in a molten state is cooled while pressed between a casting drum 3 and the corrosion-resistant endless metal belt 4 fitted over at least three metal rolls having horizontal axial lines and having flexibility imparted thereto under definite tension in a circular arc shape to be formed into a sheet. In this case, the casting drum 3 is composed of a cooling roller and cylindrical bodies 8 are attached to both end parts of the cooling roller 3 and the outer diameter of each of the cylindrical bodies 8 is made slightly larger than that of the cooling roller 3 and the width of the endless metal belt 4 is set so as to reach the surfaces of the large diameter parts of both end parts of the casting drum 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin sheet or film manufacturing apparatus suitable for packaging foods, stationery such as files, various packaging cases, and various industrial applications.

[0002]

2. Description of the Related Art Air knife method and polishing roller method are known as methods for producing the thermoplastic resin sheet or film.

[0003]

In the former air knife method, since a sheet or film is manufactured by press-bonding a film-like molten resin onto a cast drum with air pressure blowing from a nozzle, it is possible to vary the thickness of the sheet to which air is blown. The surface smoothness cannot be maintained, and one side of the sheet or film cannot be rapidly cooled because it is cooled by air. As a result, there is a drawback that a sheet or film excellent in surface smoothness and thickness accuracy cannot be formed. The upper limit of the pressure force of this air is about 3000 mm of water column, and since there is only one point of pressure contact with air, the production speed of a sheet or film of commercial value is about 20 m / min. Therefore, the air knife method is mainly used for producing a thin sheet or film having a thickness of about 0.2 to 0.5 mm, which does not require the appearance characteristics of the sheet or film, but the thickness is about 0. Not suitable for producing thick sheets of 7 mm or more.

The latter polishing roller method is a method of producing a sheet by sandwiching a film-like molten resin between a pair of metal rollers, and the contact between the pair of rollers simultaneously forms the sheet thickness and surface property. In order to complete, a sheet with excellent surface smoothness can be obtained when the take-up speed is as low as about 4 m / min or less, but when the take-up speed is about 6 m / min or more, the shaping of the sheet cannot be followed and it has commercial value. No sheets can be obtained. In addition, since a wavy wave is generated in a thin sheet having a thickness of about 0.4 mm or less, it becomes impossible to produce a sheet having a commercial value. In order to solve the above-mentioned problems of the prior art, a method and an apparatus for producing a thermoplastic resin sheet or film at high speed, which has excellent appearance characteristics such as gloss and surface smoothness regardless of the thickness of the sheet or film, are provided. Applicant has developed the patent application No. 4-35217
Filed as No. 8. The developed device has achieved some results, but there are still matters to be improved.

That is, in this apparatus, a film-shaped thermoplastic resin extruded in a molten state from a T-die is engaged with a cast drum and three metal rollers having at least horizontal axis lines, and a certain tension is applied to provide flexibility. With a corrosion-resistant metal endless belt that has been imparted with an arc in a manufacturing device that cools into a sheet shape while pressing it in an arc, an extruder abnormality occurs during sheet or film molding, or a melted resin When the supply is interrupted, the outer peripheral surface of the cast drum and the metal endless belt come into direct contact,
The outer peripheral surface of the cast drum and the metal endless belt will be scratched, and the smoothness of the sheet or film will not be obtained when the production is restarted, and the cast drum and the metal endless belt will have to be replaced, resulting in an increase in the manufacturing cost. .

Even if the above-mentioned scratch accident does not occur,
When the sheet or film is restarted, the cast drum is lowered by about 50 mm and the positions of the three metal rollers are adjusted to maintain the metal endless belt in a tensioned state, and the sheet or film is placed in the widened gap between the cast drum and the metal belt. After the film is extruded again and pulled out through this gap, it takes time and effort to reset the cast drum to its original position, restore the position of the roller, and restart the sheet or film molding to the desired gap size. It is an object of the present invention to provide the market with an apparatus for manufacturing a thermoplastic resin sheet or film, which improves the above-mentioned drawbacks and prevents the metal endless belt from directly contacting the cast drum even when the supply of the molten resin is interrupted. .

[0007]

In order to solve the above-mentioned problems, a specific invention is a film-shaped thermoplastic resin extruded in a molten state from a T-die and a cast drum and three metal rollers having at least horizontal axes. In a manufacturing device that is cooled to a sheet shape while being pressed in an arc shape with a corrosion-resistant metal endless belt that is applied with a certain tension and imparts flexibility, the outer diameter of both ends of the cast drum is
The apparatus for producing a thermoplastic resin sheet or film is characterized in that it has a diameter slightly larger than the outer diameter of the intermediate portion, and the width of the metal endless belt is such that it reaches the surface of the large diameter portion.

In order to solve the above-mentioned problems, the cast drum in the manufacturing apparatus comprises a cooling roller, and a cylindrical elastic body is attached to both ends of the cooling roller, and the outer diameter of the cylindrical elastic body is equal to that of the cooling roller. It is desirable that the diameter is slightly larger than the outer diameter.

In order to solve the above-mentioned problems, the cylindrical body in this manufacturing apparatus may be made of hard rubber or plastic and may be detachably attached to both ends of the cooling roller.

In order to solve the above problems, the width of the cylindrical body of this manufacturing apparatus is about 30 mm, and the difference in the outer diameter between the cooling roller and the cylindrical body is about 0.05 mm to 0.1 mm. desirable. In order to solve the above problems,
On the downstream side of the extrusion nozzle of the T die in this manufacturing apparatus,
A cast drum that receives the thermoplastic resin extruded from the nozzle into the gap, and a first metal roller located above the cast drum are arranged as a pair,
The first metal roller is provided so as to be able to move toward and away from the cast drum, and a second roller that is in contact with the peripheral surface of the cast drum on the downstream side from the approach point between the cast drum and the first metal roller. There is a metal roller of
The metal endless belt is engaged under a constant tension between these two metal rollers and the third metal roller, and in the area between the first and second metal rollers, the metal endless belt is While having the flexibility to run along the peripheral surface of the cast drum, the surface of the first metal roller for pressing the metal endless belt on the cast drum is coated with heat-resistant rubber or elastic elastomer. In addition, the axes of the three metal rollers are horizontal. In order to solve the above-mentioned problems, the metal endless belt of this invention is SU
It is preferably made of S, a kind of carbon steel or titanium alloy.

As the polypropylene resin which is one of the crystalline thermoplastic resins used in the present invention, crystalline propylene homopolymer or propylene is copolymerized with one or more kinds of comonomer other than propylene such as ethylene and butene. Crystalline copolymers and mixtures thereof are used. These polypropylene resins include antioxidants, lubricants, antistatic agents, slip agents, anti-blocking agents, UV absorbers, nucleating agents, transparency improvers, organic peroxides, pigments, inorganic materials such as talc and calcium carbonate. In some cases, a system filler, an organic filler such as wood powder or synthetic fiber, another resin or rubber such as polyethylene or ethylene propylene rubber may be appropriately added and used. Further, other thermoplastic resins include polyethylene, polystyrene, and AB.
S, polyethylene terephthalate, polybutylene terephthalate, polyamide, polycarbonate, vinyl chloride or the like can be used. The sheet or film production apparatus is also applicable to the production of multilayer sheets or laminated sheets. If necessary, the sheet or film thus produced is directly introduced into a water tank for secondary cooling, and then the cooling liquid adhering to the sheet surface is removed, and then the heat distortion temperature of the thermoplastic resin using this sheet. When the heat treatment is performed in the temperature range of -40 ° C to the heat distortion temperature + 15 ° C, the transparency of the crystalline thermoplastic resin increases.

[0012]

The operation of the invention described in claim 1 will be described below. Similar to the ordinary T-die method, the molten film-like thermoplastic resin extruded from the T-die is cooled while being pressed in an arc shape between the intermediate portion of the cast drum and the metal endless belt, or a sheet having a desired thickness or It is manufactured into a film. When the supply of the molten resin from the T-die is interrupted due to an abnormality in the extruder, a power failure, etc. during the molding of this sheet or film, the molten resin disappears on the cast drum, but the metal endless belt is curved in an arc shape. From the center to the axial direction, the intermediate portion of the cast drum is in a bridged state and does not contact the cast drum, and the metal endless belt makes contact only at both ends of the cast drum. No scratches are generated on both the outer peripheral surface of the sheet and the surface of the metal endless belt. Then, at the start of re-forming the sheet or film, the metal endless belt is brought into contact with both ends of the cast drum, and the film heat in a molten state extruded from the T die into the gap between the intermediate portion of the cast drum and the metal endless belt. A plastic resin is supplied, flowed along the arc portion, drawn out from the arc portion, and made into a sheet or film, and then the cast drum is relatively separated from the metal endless belt and set to a desired thickness. After that, a sheet or film having a desired thickness is continuously formed.

In the invention described in claim 2, the cast drum comprises a cooling roller, and a cylindrical elastic body is attached to both ends of the cooling roller, and the outer diameter of the cylindrical elastic body is the outside of the cooling roller. Since the diameter is slightly larger than the diameter, the metal endless belt does not come into direct contact with the peripheral surface of the cooling roller in addition to the above action, and the peripheral surface of the metal endless belt is supported by the cylindrical elastic body. It In the invention described in claim 3, since the cylindrical elastic body is made of hard rubber or plastic and is detachably attached to both ends of the cooling roller, the metal endless belt is made of hard rubber. Alternatively, the cylinder is flexibly supported by a plastic cylinder, and when the cylinder is worn, the cylinder is removed from each end of the cooling roller and replaced with a new cylinder. In the invention described in claim 4, the width dimension of the cylindrical body is about 30 mm, and the difference in outer diameter dimension between the cooling roller and the cylindrical body is 0.05 mm to 0.1 mm.
Since it is of a degree, it operates in the same manner as the invention described in claims 1 and 2.

In the invention described in claim 5, T
On the downstream side of the extrusion nozzle of the die, a cast drum that receives the thermoplastic resin extruded from this nozzle in its gap and a first metal roller located above this cast drum are arranged as a pair. A metal roller is provided so as to be able to approach and separate from the cast drum, and a second roller that is in contact with the peripheral surface of the cast drum on the downstream side from the approach point of the cast drum and the first metal roller.
The metal endless belt is engaged under a constant tension between these two metal rollers and the third metal roller, and the area between the first and second metal rollers is arranged. In the above, the metal endless belt has flexibility to run along the peripheral surface of the cast drum, and the surface of the first metal roller for pressing the metal endless belt on the cast drum is made of heat-resistant material. The thermoplastic resin sheet or film manufacturing apparatus is characterized in that it is covered with rubber or an elastomer having elasticity, and the axes of the three metal rollers are horizontal. In addition to the function of the invention described above, a film extruded in a molten state from the T die by setting the first metal roller in a state of being brought close to the peripheral surface of the cast drum. Of the thermoplastic resin is supplied between the metal endless belt and cast drum that engages the first metal roller, then the cast drum and the first, second
Of the film-shaped thermoplastic resin, which is guided by the metal roller and the metal endless belt to the arc-shaped pressing portion formed by the cast drum and the metal endless belt.
Is absorbed by the heat-resistant rubber or elastomer having elasticity.

[0015]

EXAMPLES Next, typical examples of the invention described in claims 1 to 6 will be described below. In FIG. 1, 1 is T
On the downstream side of the extrusion nozzle of the T-die 1, a cast drum 3 that receives the molten polypropylene resin 2 extruded from the nozzle in its gap and a first metal roller 5 located above the cast drum 3 are paired. The first metal roller 5 is equipped so as to be able to approach and separate from the cast drum 3. A second metal roller 6 is arranged on the downstream side in contact with the peripheral surface of the cast drum 3 in the rotation direction of the cast drum from the approach point between the cast drum 3 and the first metal roller 5, The metal endless belt 4 is engaged between the two metal rollers 5 and 6 and the third metal roller 7 with a constant tension. This metal endless belt 4 is
In the area 8 between the second metal rollers 5 and 6, running along the peripheral surface of the cast drum 3 and having flexibility so as to cool the resin 2 while pinching it to form a sheet-like shape 9, The surface of the first metal roller 5 for pressing the metal endless belt 4 on the cast drum 3 is coated with heat-resistant silicone rubber or elastic elastomer. This coating thickness is 5-15 mm,
The rubber hardness of the elastomer used is preferably 55 to 85 degrees. The cast drum 3 comprises a cooling roller,
The cylindrical body 10 is attached to both ends of this cooling roller,
The outer diameter of the cylindrical body 10 is slightly larger than the outer diameter of the cooling roller 3. The width of the metal endless belt 4 is such that the width of the metal endless belt 4 reaches the cylindrical bodies 10 (see FIG. 2). The cylindrical body 10 is made of hard rubber or plastic and is detachably attached to both ends of the cooling roller 3. The width of the cylindrical body 10 is about 30 mm, and the difference in outer diameter between the cooling roller 3 and the cylindrical elastic body 8 is about 0.05 mm to 0.1 mm.
Further, the axes of the three metal rollers 5, 6, 7 are horizontal. The surface roughness of the cast drum 3 is 0.5 μ.
m or less, preferably 0.3 μm or less. The metal endless belt 4 is made of SUS, a kind of carbon steel or titanium alloy, and SUS is preferable from the viewpoint of corrosion resistance.

The surface roughness of the metal endless belt 4 in contact with the molten resin is 0.5 μm or less, preferably 0.
This metal endless belt 4 is preferably 3 μm or less.
Is used as a belt by welding a thin metal plate, it is necessary to prevent the unevenness of the weld joint from affecting the sheet. When the thickness of the metal endless belt 4 is thin, unevenness is likely to occur in the connecting portion, and when it is thick, the flexibility of the metal endless belt 4 is lost and use is hindered. Therefore, the thickness of the metal endless belt is 0.5 to 1.2 mm. The degree is appropriate. The operation of the above-described embodiment is the same as the operation of the invention described in the corresponding claims, and thus the description thereof is omitted here.

[0017]

According to the manufacturing apparatus of the specific invention described in claim 1, when the supply of the molten resin from the T-die is interrupted due to an abnormality in the extruder, a power failure, etc. during the molding of the sheet or film, the metal The metal endless belt does not come into contact with the intermediate portion of the cast drum, but the metal endless belt makes contact only at both ends of the cast drum, and the metal endless belt can eliminate the occurrence of scratches on the outer peripheral surface of the cast drum. Then, at the time of starting the re-forming of the sheet or film, the metal endless belt is brought into contact with both ends of the cast drum, and the T end is formed in the gap between the intermediate portion of the cast drum and the metal endless belt.
A molten film-like thermoplastic resin extruded from a die is supplied, flowed along the arc portion, pulled out from this arc portion, made into a sheet or film, and then the cast drum is relative to the metal endless belt. After separating and setting to a desired thickness, a sheet or film having a desired thickness can be continuously formed, and the setup work can be easily performed even for women and women such as parts and the setup time can be shortened.

In the invention described in claim 2, the cast drum comprises a cooling roller, and cylindrical elastic bodies are attached to both ends of the cooling roller, and the outer diameter of the cylindrical body is the outer diameter of the cooling roller. In addition to the above effect, the metal endless belt does not come into direct contact with the peripheral surface of the cooling roller when the supply of the molten resin is interrupted. It can support both ends of the endless belt. In the invention described in claim 3, since the cylindrical body is made of hard rubber or plastic and is detachably attached to both end portions of the cooling roller, both end portions of the metal endless belt are The elastic cylindrical body made of hard rubber or plastic can flexibly support when the supply of the molten resin is interrupted, and when the cylindrical body is worn for a long time and is worn, the cylindrical body is removed from each end of the cooling roller, and Can be replaced with a cylinder.
Further, even if the metal roller 5 or 6 may accidentally collide with the cast drum in the preparatory stage before the operation of this apparatus, the impact is absorbed by the elastic cylindrical body 8, and the surface of the cast drum 3 is absorbed. Also, the surface of the metal endless belt 4 is not damaged. In addition, since this cylindrical body is softer than the metal endless belt, even if they contact each other, the metal endless belt is hardly damaged and the expensive metal endless belt is hardly damaged. It is not necessary to polish, the cylindrical body is mainly worn, and the maintenance and management of the entire device is easy and the cost can be reduced. In the invention described in claim 4, the width of the cylindrical elastic body is about 30 mm, and the difference in outer diameter between the cooling roller and the cylindrical elastic body is 0.05.
Since it is about 0.1 mm to 0.1 mm, the above-mentioned claim 1
The same effects as those of the invention described in claim 2 are obtained, the structure is simplified without lengthening the cooling roller, and it is suitable for forming a thick film of 0.3 mm or more.

In the invention described in claim 5, T
On the downstream side of the extrusion nozzle of the die, a cast drum that receives the thermoplastic resin extruded from this nozzle in its gap and a first metal roller located above this cast drum are arranged as a pair. A metal roller is provided so as to be able to approach and separate from the cast drum, and a second roller that is in contact with the peripheral surface of the cast drum on the downstream side from the approach point of the cast drum and the first metal roller.
The metal endless belt is engaged under a constant tension between these two metal rollers and the third metal roller, and the area between the first and second metal rollers is arranged. In the above, the metal endless belt has flexibility to run along the peripheral surface of the cast drum, and the surface of the first metal roller for pressing the metal endless belt on the cast drum is made of heat-resistant material. The thermoplastic resin sheet or film manufacturing apparatus is characterized in that the three metal rollers are covered with rubber or an elastomer having elasticity, and the axes of the three metal rollers are horizontal. In addition to the effects of the invention described above, a film extruded in a molten state from the T die by setting the first metal roller in a state of being brought close to the peripheral surface of the cast drum. Of the thermoplastic resin is supplied between the metal endless belt and cast drum that engages the first metal roller, then the cast drum and the first, second
The metal roller and the metal endless belt can guide the arc-shaped pressing portion formed by the cast drum and the metal endless belt, and the variation in the molding thickness of the film-shaped thermoplastic resin can be transferred to the first metal roller. It can be absorbed with the above-mentioned heat-resistant rubber or elastic elastomer coated.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an example.

FIG. 2 is a partially cutaway enlarged view showing a relationship between a cast drum and a metal belt.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 T-die 2 Membrane polypropylene resin 3 Cast drum 4 Metal endless belt 5 First metal roller 6, 7 Second and third metal roller 8 Cylindrical body

Claims (6)

[Claims] 1. A film-shaped thermoplastic resin extruded in a molten state from a T-die is interlocked with a cast drum and three metal rollers having at least horizontal axis lines, and a constant tension is applied to impart flexibility. In a manufacturing device that cools into a sheet shape while pressing it in an arc shape with a corrosive metal endless belt, the outer diameter of both ends of the cast drum is
An apparatus for manufacturing a thermoplastic resin sheet or film, wherein the metal endless belt has a diameter slightly larger than the outer diameter of the intermediate portion, and the width of the metal endless belt reaches the surface of the large diameter portion. 2. The cast drum comprises a cooling roller, and a cylindrical body is attached to both ends of the cooling roller,
The thermoplastic resin sheet or film manufacturing apparatus according to claim 1, wherein the outer diameter of the cylindrical body is slightly larger than the outer diameter of the cooling roller. 3. The apparatus for producing a thermoplastic resin sheet or film according to claim 2, wherein the cylindrical body is made of hard rubber or plastic and is detachably attached to both ends of the cooling roller. 4. The thermoplastic resin sheet according to claim 2, wherein the width of the cylindrical body is about 30 mm, and the difference in outer diameter between the cooling roller and the cylinder is about 0.05 mm to 0.1 mm. Or film manufacturing equipment. 5. A cast drum, which receives the thermoplastic resin extruded from this nozzle in its gap, and a first metal roller located above this cast drum, are arranged as a pair on the downstream side of the extrusion nozzle of the T die. Yes, this first
The metal roller of the cast drum is provided so as to be able to approach and separate from the cast drum, and in the rotation direction of the cast drum from the approach point of the cast drum and the first metal roller, the metal roller of the Second to contact
The metal endless belt is engaged under a constant tension between these two metal rollers and the third metal roller, and the area between the first and second metal rollers is arranged. In the above, the metal endless belt has flexibility to run along the peripheral surface of the cast drum, and the surface of the first metal roller for pressing the metal endless belt on the cast drum is made of heat-resistant material. The thermoplastic resin sheet or film manufacturing apparatus according to claim 1, wherein the three metal rollers are covered with rubber or an elastomer having elasticity and the axes of the three metal rollers are horizontal. 6. The apparatus for manufacturing a thermoplastic resin sheet or film according to claim 1, 2, 3, 4, or 5, wherein the metal endless belt is made of SUS, carbon steel or a titanium alloy.