JPH08156073A - Production equipment of thermoplastic resin sheet or film - Google Patents

Abstract

PURPOSE: To realize the production of thin film, which has no fish-eye gel and is less apt to shrink by a method wherein the hardness and thickness of the rubber, which covers the outer peripheral surface of a metal roller opposing to a casting drum. CONSTITUTION: By cooling a filmy thermoplastic resin under a molten state by being extruded from a T-die 1 under the condition being arcuately and elastically pinched between a casting drum 3 and a flexible and corrosion- resistant metal endless belt 4, which is spanned among at least three metal rollers 5, 6 and 7 having horizontal axis lines under a certain tension, sheet or film 9 is produced. In this case, the hardness of the rubber covering the outer peripheral surface of the metal roller opposing to the casting drum 3 is 75-80 in accordance with JIS-K 6301 in JIS-A degree. Its thickness is 2-3mm. Further, the width of the metal endless belt 4 is nearly equal to that of filmy molten resin extruded from the T-die 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a thermoplastic resin sheet suitable for packaging foods, stationery such as files, cases for various packages, protective films, raw materials for lamination, various industrial applications, and the like. The present invention relates to a film manufacturing apparatus.

[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 produced by press-bonding a film-like molten resin onto a cast drum with air pressure blowing from a nozzle, there is a fluctuation in the thickness of the sheet to which air is blown. Up,
The smoothness of the surface 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 the air is about 3000 mm of water column, and the production speed of the sheet or film of commercial value is about 20 m / min because the pressure point of the air is a straight line in the transverse direction. Therefore, the air knife method is mainly used for producing a thick 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 the production of thin sheets less than 0.2 mm.

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
No. 8 (JP-A-6-174919). The developed device has achieved some results, but there are still matters to be improved.

That is, in this apparatus, when a thin film having a thickness of 100 μm or less is manufactured, it is extruded from a T-die through a corrosion-resistant metal endless belt between a cast drum and a rubber-coated metal roller. In order to cool the film-shaped thermoplastic resin while pressing it, both end parts of the cast drum that are not in contact with the molten resin are curved toward both ends of the metal roller, and the peripheral surface is concave on the generatrix, Both the metal endless belt and the cast drum contact each other at their ends, failing to apply sufficient sandwiching pressure, which may lead to a situation in which a thin sheet or film cannot be formed. Further, the rubber coating layer of the metal roller may be deformed, or the end portion of the metal endless belt may be curved downward to come into contact with the peripheral surface of the cast drum. The present invention improves the above-mentioned drawbacks, does not involve fisheye gel, and does not hinder shrinkage, and is capable of producing even a thin film or sheet having a thickness of 100 μ or less, or a thermoplastic resin sheet or The purpose is to provide film manufacturing equipment to the market.

[0006]

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 metals having at least a horizontal axis. In a manufacturing apparatus for cooling a sheet while being elastically pressed in an arc shape with a corrosion-resistant metal endless belt that is hooked on a roller and is given a certain amount of flexibility, the outer periphery of the metal roller facing the cast drum The hardness of the rubber coating the surface is JIS-K6
According to JIS-A degree of 301, the hardness is 75 to 80,
The thickness of the thermoplastic resin sheet or film is 2 mm to 3 mm.

In order to solve the above-mentioned problems, it is structurally desirable that the cast drum in the manufacturing apparatus is a crown roller.

In order to solve the above-mentioned problems, a thermoplastic resin sheet is characterized in that the central portion of the cast drum in this manufacturing apparatus is substantially cylindrical and both ends thereof are tapered truncated cones. Alternatively, it is preferable in the production of the film.

In order to solve the above-mentioned problems, the width of the metal endless belt of this manufacturing apparatus is almost matched with the width of the molten resin supplied from the T die, and the width of the cast drum and It is desirable for forming the thermoplastic resin sheet or film that the metal roller facing the cast drum is formed. In order to solve the above-mentioned problems, the resin discharge port of the T die in this manufacturing apparatus is provided with a width regulating tool that makes the width of the molten resin from the T die slightly narrower than the width of the metal endless belt. It is characterized by

In order to solve the above-mentioned problems, it is preferable that the metal endless belt of the present invention is made of SUS, 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, as the other thermoplastic resin, polyethylene, polystyrene, ABS, polyethylene terephthalate, polybutylene terephthalate, polyamide, polycarbonate, vinyl chloride, methacrylic resin, ethylene vinyl alcohol copolymer resin 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.

[0013]

The operation of the invention described in claim 1 will be described below. As in the ordinary T-die method, the molten resin extruded from the T-die is continuously supplied between the intermediate portion of the cast drum and the metal endless belt, and while being conveyed between them, the molten resin is circular. It is cooled while being pressed in an arc shape and manufactured into a sheet or film having a desired thickness. At this time, since the hardness of the coating rubber of the metal roller is 75 to 80 and the thickness thereof is 2 to 3 mm, both ends of the cast drum do not come into contact with the metal roller, and both ends of the metal belt are cast drum. The molten resin is produced into a film or sheet having a thickness of 100 μm or less at a desired pressure without contacting the peripheral surface of the film. At this time, the pressing force of the cast drum against the metal belt is sufficiently exerted, and the fish eye gel, which is easily noticeable on the thin film or sheet, is crushed, and its properties such as transparency can be enhanced, and non-oriented molding can be performed. Therefore, product shrinkage does not occur.

In the invention described in claim 2, in addition to the function of the invention described in claim 1, since the cast drum is a crown roller, the cast drum is pressed against the metal roller to compress the molten resin. However, the both ends of the metal belt are not in contact with the peripheral surface of the cast drum, and the molten resin is produced into a film or sheet having a thickness of 100 μm or less at a desired sandwiching pressure.

In the invention described in claim 3, since the central portion of the cast drum is substantially cylindrical and both ends thereof are tapered truncated cones,
It operates similarly to the invention described in claim 2.

According to the invention described in claim 4, in addition to the operation of the invention described in claims 1 to 3, the width of the metal endless belt is made to approximately match the width of the molten resin supplied from the T die. The cast drum and the metal roller facing the cast drum are formed to be slightly wider than the cast drum.
In addition to the same effect as the invention described in, the amount of both ends of the cast drum and both ends of the metal roller protruding from both sides of the film or sheet is extremely short, so that the end of the cast drum and the end of the metal roller due to deformation are There is less chance of contact.

In a fifth aspect of the invention, the resin discharge port of the T die is provided with a width regulating tool for making the width of the molten resin from the T die slightly narrower than the width of the metal endless belt. Therefore, in addition to the action of the invention described in claims 1 to 4, the extrusion width of the molten resin is restricted to the width to be produced at the stage before the pressure is applied.

Since the invention according to claim 6 is characterized in that the metal endless belt is made of one of SUS, carbon steel and titanium alloy, the same operation as the invention according to claims 1 to 5 is achieved. .

[0019]

EXAMPLES Next, typical examples of the invention described in claims 1, 2, 4, 5 and 6 will be described below. In FIG.
Reference numeral 1 denotes a T-die, and a film-shaped thermoplastic resin extruded in a molten state from the T-die 1 is engaged with a cast drum 3 and three metal rollers 5, 6 and 7 having at least a horizontal axis, and fixed. The width of the metal endless belt 4 in the manufacturing apparatus for manufacturing the sheet or film 9 by elastically pressing in an arc shape with the corrosion-resistant metal endless belt 4 to which flexibility is applied by applying the tension The width of the film-like molten resin extruded from No. 1 is almost the same as the width. The cast drum 3 and the metal roller 5 facing the cast drum 3 are formed slightly wider than the width of the metal belt 4, and a rubber covering the outer peripheral surface of the metal roller 5 facing the cast drum 3 is formed. The hardness is set to 75 to 80 according to JIS-A degree of JIS-K6301, and the thickness is set to 2 mm to 3 mm. Between the cast drum 3 and the metal roller 5 facing the cast drum 3, a sandwiching portion 2 of a film-like thermoplastic resin extruded from the T die 1 via the metal endless belt 4 is formed. There is. The cast drum 3 is a crown roller (see FIG. 2).

The shape of the cast drum 3 is not limited to the shape shown in FIG. 2, and the center portion of the cast drum 3 may be substantially cylindrical, and both ends thereof may be tapered truncated cones (claim 3). Corresponding to the invention described). Further, the cast drum 3 and the metal roller 5 facing the cast drum 3 may have a short cylindrical shape shown in FIG. The T-die 1
A width regulating tool (not shown) having a resin width slightly narrower than that of the metal endless belt 4 is attached to the resin discharge port. The metal endless belt 4 is made of SUS, carbon steel or a titanium alloy.

[0021]

According to the first aspect of the invention, the molten film-like thermoplastic resin extruded from the T-die is supplied to substantially the width of the metal endless belt, as in the ordinary T-die method.
This molten resin can be cooled while being pressed in an arc shape between the intermediate portion of the cast drum and the metal endless belt to be manufactured into a smooth sheet or film having a desired thickness. In particular, at this time, the hardness of the rubber covering the outer peripheral surface of the metal roller facing the cast drum is 75 to 80 according to JIS-A degree of JIS-K6301, and the thickness thereof is 2 to 3 mm. The ends of the cast drum are not in contact with the opposing metal rollers, and the ends of the metal belt are not in contact with the peripheral surface of the cast drum, and the molten resin is formed into a film or sheet having a thickness of 100 μm or less at a desired pressure. Can be manufactured. Outside the rubber thickness range and outside the rubber hardness range, the amount of deformation of the coated rubber of the metal roller increases,
The smoothness and transparency of the film or sheet are impaired.

In the invention described in claim 2, in addition to the effect of the invention described in claim 1, since the cast drum is a crown roller, the cast drum is pressed against the metal roller and the molten resin is pressed down. However, both ends of the metal belt do not come into contact with the peripheral surface of the cast drum, and the molten resin can be produced into a film or sheet having a thickness of 100 μm or less at a desired clamping pressure.

In the invention described in claim 3, since the central portion of the cast drum is substantially cylindrical and both ends thereof are tapered truncated cones, the structure of the cast drum is slightly improved. In addition to the effect of the invention of claim 1, a cast drum is pressed against the metal roller,
Even if the molten resin is pressed, both ends of the metal belt are not in contact with the peripheral surface of the cast drum, and the molten resin can be produced into a film or sheet having a thickness of 100 μm or more at a desired pressing pressure.

In the invention as set forth in claim 4, the width of the metal endless belt is approximately matched with the width of the molten resin supplied from the T die, and the cast drum and the cast drum are slightly wider than this. Since the metal roller facing the drum is formed, the same effect as that of the invention according to claims 1 to 3 can be obtained, and both ends of the cast drum and both ends of the metal roller protrude from both sides of the film or sheet. Is extremely short, the possibility of contact between the end of the cast drum and the end of the metal roller due to deformation can be eliminated, the life of the cast drum and the metal roller can be extended, and the manufacturing cost thereof can be reduced.

In the invention described in claim 5, since the width of the molten resin from the T die is slightly narrower than that of the metal endless belt, a width regulating tool is attached to the resin discharge port of the T die. In addition to the effects of the invention described in claims 1 to 4, it is possible to regulate the extrusion width of the molten resin to the width to be produced at the stage before the pressing.

In the invention according to claim 6, since the metal endless belt is made of SUS, carbon steel or a titanium alloy, the same effects as those of the invention according to claims 1 to 5 can be obtained. .

[Brief description of drawings]

FIG. 1 is a schematic side view of an embodiment.

FIG. 2 is a front view showing a relationship between a cast drum and a metal belt.

FIG. 3 is a front view showing a different aspect of the cast drum.

[Explanation of symbols]

 1 T-die 2 Membrane polypropylene resin 3 Cast drum 4 Metal endless belt 5 Rubber-coated metal roller

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 apparatus that cools into a sheet shape while elastically pressing in an arc shape with a corrosive metal endless belt, the hardness of the rubber coating the outer peripheral surface of the metal roller facing the cast drum is JIS-K6301 JIS-A. Hardness to 75-80 according to the degree, and its thickness is 2mm-3m
m is a device for producing a thermoplastic resin sheet or film. 2. The apparatus for producing a thermoplastic resin sheet or film according to claim 1, wherein the cast drum is a crown roller. 3. The apparatus for producing a thermoplastic resin sheet or film according to claim 1, wherein the center portion of the cast drum is substantially cylindrical and both ends thereof are tapered truncated cones. 4. The width of the metal endless belt is substantially matched with the width of the molten resin supplied from the T die, and the cast drum and the metal roller facing the cast drum are formed slightly wider than this. 4. The apparatus for producing a thermoplastic resin sheet or film according to claim 1, 2 or 3, wherein: 5. The width regulating tool for making the width of the molten resin from the T-die slightly narrower than the width of the metal endless belt is attached to the resin discharge port of the T-die. An apparatus for manufacturing a thermoplastic resin sheet or film according to 2, 3, or 4. 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.