JPS62179915A - Manufacture of thermoplastic resin sheet or film - Google Patents

Abstract

PURPOSE:To make it possible to recycle sheet- or film-shaped scrap material by a method wherein said scrap is cleaned, ground and cut. CONSTITUTION:Thermoplastic resin is extruded through a die 3 in the form of a sheet, both ends of which are cut off at an edge trimming section 4 and the central part (a) of which is taken up to a take-up roll 5 in order to be successively turned into product. On the other hand, the cut-off trimmings (b) are taken up to a take-up roll 6 and then sent to a web cleaner 10, in the suction chambers 12a and 12b of which dust adhered to the edge trimmings are swept off with rotary brushes 11a and 11b and recovered. The resultant clean trimmings are sent to a grinder 7 so as to be finely ground as raw recycling material (d) and then sent to a mixer 8 in order to be mixed with raw virgin material (e) and then supplied again to the hopper 2 of an extruder 1 to be formed into a sheet, some part of which is used again as raw recycling material.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is designed to remove trimming debris and slit ink debris generated during the production of sheets or films using heat and viscous resin. The present invention relates to a method for producing a thermoplastic IIr/ql resin sheet or film that can be recovered and used as a raw material.

[Conventional technology] Heat leaf・η! When manufacturing a sheet or film (hereinafter referred to as "sheet" including filtration) using synthetic resin, both ends of the sheet will be thicker or thinner than the other parts, so the sheet width during extrusion may be smaller than the desired width. I leave it wide and then trim both ends with a cutter. In addition, slitting is performed as necessary. For this reason, in the process of manufacturing sheets, it is impossible to avoid the generation of trimming scraps and slitting Is. From the viewpoint of cost savings and resource conservation, it is necessary to recycle sheets by returning them to an 11-degree sheet manufacturing stage and turning them into products.

Conventionally, when recycling the trimming scraps and slitting scraps mentioned in 14, these scraps are collected, crushed or cut into small pieces as they are, and then mixed with virgin raw material 1 and fed to an extrusion molding machine. was.

[Problems to be solved] In the conventional recycling method described above, the collected trimming scraps, etc. are crushed or cut as they are without cleaning, and the recycling b: (ne 1) is used. The dust mixed in with the raw material is a major cause of frequent fish eyes and poor appearance on the manufactured sheet 1-.In addition, when there is a lot of dust, , or heat f+(1'?!) Depending on the type of resin and the weight of the product, it may be difficult to recycle and use these scraps.

In addition, even if the negative effects of the sheet itself are small, when this sheet is subjected to secondary ripening or stretch forming, it has the disadvantage of causing phenomena such as holes and stretch cutting. In order to reduce this drawback, there was a problem in that the amount of recycled raw material 1 to be mixed with Yashin Genzai 1 had to be significantly limited.

As an L step to prevent dust from adhering to glue and slinting waste, it is conceivable to cover the sheet manufacturing step with a dustproof device to make it cleaner, but this would require a large amount of equipment. It was impractical because it was expensive.

The present invention was made in view of the IS circumstances described in L.
An f$ that reliably removes dust attached to recycled trimming waste, etc. with a simple or reach method, and allows production of high-quality sheets even when recycled raw materials are used.
+1 (Providing a method for producing a q-type resin sheet or film is the second priority.

[Means for Solving the Problems] In order to achieve objective 1, the method for producing a heat-resistant Ir plastic resin sheet or film of the present invention reduces the amount of heat generated during step 1 of producing a sheet or film made of plastic resin. In this method, sheet-like or film-like waste is cleaned through a web cleaner, and then crushed or cut into recycled raw materials, and this raw material is used to manufacture sheets or films.

[Example] Hereinafter, an uninvented example method will be described with reference to the drawings.

FIG. 1 shows an example of a device for implementing the wooden sword U. In the figure, 1 is an extrusion molding machine, which melts and kneads the 811 plastic resin supplied from the hopper 2 and extrudes it into a sheet form from the die 3 at the tip. ,
Heat both ends of the plastic resin! , is an Ir cutting part that cuts IJ, and although detailed drawings are omitted, a Saayaura Kantha is used. As a cutter for the rr cutting section, a knife (when the sheet is thin), a rotary circular saw (when the sheet is thick), etc. can also be used. Reference numeral 5 denotes a take-up roll for the sheet a which has been trimmed to a predetermined width, and 6 is a take-up roll for taking up the trimming waste of the cut 1 part. Remove slinting waste C, etc. generated during post-processing.
Sometimes the inside is removed at the same time as the trimming waste of the part.

7 is a crusher (cutting machine) for trimming waste.

It is ground into a fine powder that can be used as recycled raw material. 8 is a mixture, recycled raw material d and 8-jino raw material e
are mixed and supplied to hopper 2 of extruder 1. Note that 9 is the granulation step 1 (for example, melt extrusion pelletization [step]) used when making the pulverized recycled raw material into granules, and is added as necessary.

IO is a web cleaner, which is disposed between the take-up roll 6 of the trimming Is b and the crusher 7. This web cleaner 10 sweeps off old dust on surfaces 1 to 4 of the trimming waste.
a, llb, and a suction chamber 12a that houses the brushes 11a and llb and sucks and removes the fallen dust.
12b. Although not shown, there is also a static eliminator that removes static electricity as needed, and a rotating brush 1.
It is equipped with a brush cleaning bar to remove dust adhering to parts 1a and llb.

The web cleaner 10 may be a small knife type shown in FIG. 1, a wiping type as shown in FIGS. 2 to 4, or an air knife type * jfl r? A wave type can also be used.

The wiping type web cleaner 10 shown in FIG.
It is a contact type, and wiping cloths 13a and 13b are used.
Place these on both sides of the trimming scraps, and
Suction l3a, l3b and trimming waste 1jl
By suctioning and contacting them simultaneously with a14a and 14b, and by running 1ej13a and 13b in the opposite direction to the trimming waste, the dust adhering to the trimming waste is wiped off with the cloths 13a and 13b. . In this case, since it is necessary to suction the trimming debris together with the cloths 13a and 13b, the seven pairs of cleaners are provided so as to be shifted back and forth.

The web cleaner 10 shown in FIGS. 3 and 4 is a non-contact type, and the air-if force type web cleaner 10 shown in FIG. are provided facing each other, and air pipes 16a,
Air is ejected from l6b toward the trimming waste, and this air blows away the dust on the trimming waste! It is designed to be dropped and collected by suction using suction channels <15a and 15b. Further, the web cleaner 10 of the ultra-77 wave type shown in FIG.

A suction channel/<18a provided in close proximity to 17b.

It consists of tabs, and these are provided facing each other. Then, the dust attached to the trimming waste is removed by the ultra FF air ejected from the ejection parts 17a and 17b.
Trimming debris floating from the surface! E, and furthermore, this floating shape! Suction chambers 18a, 18 remove dust on the islands.
It is designed to be collected by suction by b.

Next, an embodiment of the method of the present invention using the above-mentioned apparatus will be described.

The plastic resin is melted and kneaded in the extrusion molding l&l and extruded into a sheet form from the goo 3. After being subjected to necessary treatment using a cooling device and a heat treatment device (not shown), In this edge cutting part 4, both ends of the sheet-shaped 8IIr plastic 4jI4+1fi are cut with a cutter, and the sheet a formed to the desired width in the center and the 1" part i and rimming waste at both cut ends are cut. The sheet a is taken up by a take-up roll 5, and is sequentially subjected to necessary processing to become a product.

The trimming waste of the cut 1" section is taken up by a take-up roll 6 and sent to the web cleaner IO.
In b, use the rotating brush lla to remove dust adhering to the inner surface of the rimming waste Lt'.

11b and collect the dust.

Clean trimming debris. The trimming waste cleaned in this way is crushed by a crusher (cutting machine a) 7.
There, it is finely pulverized as recycled raw material d and then sent to a mixer 8 by an F-duct or the like. Note that depending on the type of raw material, the type of product, etc., the raw material from the crusher 7 may be granulated by passing it through a granulation step 9. In addition, the waste to be cleaned in the web cleaner 10 to be used as recycled raw material d includes 1 part trimming JS b and slitting waste c i.

The recycled raw material d sent to the mixer 8 is mixed with the virgin raw material e in the mixer 8, and then supplied again to the hopper 2 of the extrusion molding machine L, where it is formed into a sheet through the steps described above. The remaining part is used again as recycled raw material. Incidentally, among the raw materials supplied to the hopper 2, the proportion of the recycled onion material (d) (i.e., the mixing ratio per recovery is usually 30% or more).

A more specific summary of the results obtained by the method of this example is as follows.

○ Raw materials used (l,) Virgin raw materials: Homopolypropylene resin (density 0.91g/crn', M I 2g/
10 minutes, Idemitsu Petrochemical MSJ Product name: 2 Idemitsu Polypro F200S After cleaning through a double-sided contact system consisting of a brush + suction chamber [manufactured by Huyuguru Electronics ■], it was pulverized (recovery mixing ratio 15 ton-jil-%) ○ Molding conditions: T-die extrusion equipment (extruder 9hmφ,
L/D2B, die width 730ta, die lip opening 2■
) with a resin temperature of 240°C and a die lip temperature of 280°C.
The molten resin film was then melted and kneaded to extrude a transparent molten resin film.Then, this molten resin film was introduced into a single-slit water cooling device and rapidly cooled, and then heat treated at 120°C to form a polypropylene sheet with a thickness of 0.25 layer 1. Manufactured.

○ Molding results: In this sheet) 400 m layer x 400 layers, there were 2 pieces of gain eye with l or more j = in 1 layer, and 23 pieces with Is ■ or more, which were very few.

Comparative Example The experiment was carried out in the same manner as in the example except that no web cleaner was used.As a result, FinChair had 15 pieces of layer III and above 1-, and 74 pieces of layer 1II11 and above, which is always more than J1. , the appearance was poor.

In this way, according to the embodiment method described above, even if recycled raw material °1 is used, a high-quality sheet with little gain eye and no holes or stretch breaks can be produced.
can be built. Also, since there is no limit on collection 1i), you can save money! In addition to serving as a single source, DI raw material rli
It is possible to reduce the cost and increase economic efficiency.

Furthermore, since only a simple equipment such as a web cleaner is required, operation management and quality control can be easily performed.

The method of the present invention is not limited to the above-mentioned embodiments, but includes, for example, the following application examples.

(2) Heat If (when using polyolefin (polypropylene, polyethylene), polyester, polyamide, ethylene-vinyl alcohol copolymer, etc. as the plastic resin.

(When using fatty acids or fatty acid metal salts as additives.

(3) When used for manufacturing not only single-layer but also multi-layer sheets or films.

(4) When used for manufacturing various sheets and films such as sheets, blown films, and flat films.

(5) For example, when it is used for manufacturing by various methods, regardless of whether it is stretched or not.

'6> When only one side of the trimming waste is cleaned.

[9. Effect of light] As described in l- below, according to the method of the present invention, it is possible to produce a thermal u(·r7j resin sheet or film of excellent quality) using recycled raw materials.

[Brief explanation of drawings]

FIG. 1 shows an example of an apparatus for carrying out the method of the present invention, and FIGS. 2 to 4 show schematic configuration diagrams of other examples of the web cleaner. 1. Extrusion molding machine 4: l[! , IJ section 7
: Pulverizer 8/Mixer lO: Web cleaner 11a, fib: Rotating brushes 12a, 12b: Suction chambers 14a, 14b: Suction machines 15a, 15b: Suction chambers 16a, 16b: Z-ar tubes 17a, 17b: Spout part 18a, 18b: Suction chamber

Claims (2)

[Claims] (1) Sheet-like or film-like waste generated in the process of manufacturing sheets or films made of thermoplastic resin is cleaned through a web cleaner, and then crushed or cut to be used as recycled raw materials,
A method for producing a thermoplastic resin sheet or film, characterized in that the sheet or film is produced using this raw material. (2) Production of a thermoplastic resin sheet or film according to claim 1, wherein the recycled raw material is crushed or cut edge trimming waste of a sheet or film thermoplastic resin. Method.