JPS6342837A - Manufacture of oriented film - Google Patents

Abstract

PURPOSE:To prevent the generation of holes due to the mixing of foreign materials, by a method wherein two layers or more of molded raw fabrics are laminated and bonded, thereafter, are oriented. CONSTITUTION:Respective resin sheets 1, 1 on re-winding rolls 2, 2 are preheated by preheating rolls 3, 3, thereafter, are guided to a drum roll 5 through expander rolls 4, 4 to obtain an integrated sheet 6 by bonding them through hot pressing, then, the integrated sheet 6 is sent through a separating roll 7 and is heated again by a heater 8, thereafter, is sent to an orienting process after passing between a rubber roll 9 and an embossing roll 10. The hot pressing is effected under a temperature obtained by adding 20-50 deg.C to the thermal deformation temperatures of respective resin sheets. The orientation of the polymer sheet is effected by increasing the take-off speed of a take-off roll than the rotating speed of the drum roll 5, the emboss roll 10, the rubber roll 9 and the like, and the draw ratio of the sheet is 105-500%, preferably 150-300%. According to this method, defects of generating holes in the product is eliminated out the time of manufacturing the oriented film and the yield of products may be improved remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing a stretched film (9a), and particularly to a method for producing a stretched film from an A-layer sheet to eliminate hole defects.

(Prior art and its problems) As a conventional method for producing a stretched film, it is normal to lead a raw fabric (sheet) formed by a T-die molding method or a calendar molding method to a stretching process and stretch it. The stretching ratio is 200 to 5 depending on the purpose of the stretched film.
00%, the film thickness after stretching is 10~70#
It was set to Lm. The quality problem with this stretched film is the occurrence of holes that penetrate through the front and back sides (3 rice-grain-sized holes in 1,000 m are considered defective), and the cause of this is that foreign matter mixed in the original film cannot follow the stretching. It is thought to occur because of

The paths for this foreign matter to enter are: (1) It is mixed into the raw material itself, or it becomes a foreign matter due to secondary aggregation of blended components such as pigments and fillers, and (2) The base resin itself decomposes during the molding or stretching process. Or by-products resulting from deterioration, 3'! During the II manufacturing process, some foreign matter gets mixed in from outside the system, but it is impossible to remove the mixed foreign matter by taking it out to the stretching section, and for this reason, new S measures have been developed to prevent the occurrence of holes. It was strongly requested.

(Means for solving problems) Book 9. IJl is a sII manufacturing method for stretched film that prevents the formation of perforated sheets, and its gist is to stack two or more formed raw films, fuse them together, and then stretch them. be.

Based on theory 1j1, the present inventor investigated the relationship between the thickness of the original fabric of the perforated defective stretched film 11 and the size of foreign particles, and found that the size of the foreign particles was 1/3 or less of the thickness of the original fabric. It was found that if this was the case, no holes would occur. Based on this result, we used the calender method to produce original fabrics with a thickness of 100gm, but after calendering them to a thickness of 50gm, we polymerized the two sheets (tabbing).
When it was stretched to a thickness of 100 gm,
This invention was arrived at after confirming that the surprising result of almost no occurrence of holes was produced.

Next, the details of this invention will be explained based on the accompanying drawings showing the polymerization process. In Figure 0, 1 and 1 are molded resin sheets for polymerization, and 2 and 2 are respective unwinding rolls. The combinations of resin sheets (1.1) to be subjected to this polymerization include fusso resin and vinyl chloride resin, acrylic resin and vinyl chloride resin, vinyl chloride resins together, fusso resins together, acrylic resins together, and salt and vinyl acetate resin together. Examples include polymer resins, vinyl chloride resins, and salt-vinyl-acetate combination resins, and combinations of the thicknesses of these resin sheets include:
In order to prevent tearing due to foreign matter of 1/3 or more of the above-mentioned thickness, the maximum thickness of one sheet should be 90% or less, preferably 67% (2/2) of the total thickness after polymerization. 3
) is appropriate. At 67% to 90%, even if there is a foreign object on the thicker sheet, the thinner sheet will tear,
Acts as a stopper to prevent the growth of tears; Note that the resin sheet to be subjected to polymerization is not wound up on a roll as shown in the figure, but the sheet immediately after being formed with a T-die or calendarer is directly subjected to the polymerization process. The number of resin sheets to be polymerized and the type of resin can also be changed to two or more types.
A can be selected.

Each resin sheet 1, 1 of the unwinding roll 2.2 is p240
- Expander roll 4.
4, it is led to a drum roll 5, where it is bonded by thermocompression bonding to form a single piece 6, which passes through a peeling roll 7, is heated again by a heater 8, passes between the rubber roll 3 and the embossing roll 1O, and then undergoes a stretching process. sent to.

The conditions for this thermocompression bonding are the heat deformation temperature of each resin sheet,
For example, 74-113℃ for acrylic resin, 82-115℃ for styrene resin, 77-120℃ for ABS resin.
The heating is carried out at a temperature of 100 to 130°C for propylene resin, 100 to 120°C for vinyl chloride resin, 120°C for fluoride resin, and 20 to 50°C, respectively.

The polymerization of the resin sheet in the present invention is not limited to the thermocompression bonding shown in the figure, but may also be bonded using an adhesive or a solvent. Although different, salt-vinyl acetate copolymer, synthetic rubber (tolylphenol type), urethane type,
Polymethyl methacrylate (e.g. epoxy 828:
Examples include products such as DuPont formal dress product name (for Fusso resin sheets).

The stretching of the polymerized sheet is performed by setting the take-up speed of the take-up rolls (usually composed of 5-6 rolls or more) to be higher than the rotational speed of the drum roll 5, embossing roll IO, rubber roll 8, etc. It is done by increasing. This stretching ratio is 105 to 500%, preferably 150 to 300%
It is. If it is less than 105%, no effects of stretching such as improvement of sheet orientation, heat resistance, heat shrinkability, adhesion, etc. can be expected, and if it is more than 500%, phenomena such as uneven thickness, one-sided elongation, and waving may occur in the sheet. This causes deterioration of the surface properties of the sheet, especially unevenness, misalignment, and the formation of ink pools during printing.

The stretching is carried out at a linear speed of 15 to 100 m/min. If the speed exceeds 100 m/min, cracks are likely to occur not only in areas where foreign substances are present, but also in areas where foreign substances are not present, as the sheet itself cannot stretch as quickly as possible. Even if they are used together, uneven heating tends to occur, and as a result, the sheet tends to elongate on one side, have uneven thickness, and crack. If the speed is less than 15 m/min, there will be no effect on sheet orientation, so the tensile strength of the sheet will not be the same, and the adhesion to the roll will be affected due to temperature unevenness between the side edges of the sheet and the center of the sheet. There is a difference between the side edges and the center, which tends to cause waving, stick-slip (so-called car marks), and folding of the sheet. Even if the sheet is heated using some means, the sheet is likely to decompose, resulting in fading and color change.

Next, the present invention will be explained using examples.

Examples 1 to 3, Comparative Examples 1 to 2 TK700 (manufactured by Shin-Etsu Chemical Co., Ltd., trade name) 100 weight ¥81S (same hereafter) as polyvinyl chloride, LS-140 (manufactured by Akishima Chemical Co., Ltd., product) as a heat stabilizer 2 parts of mercaptotin series), 5 parts of dioctyl phthalate as a plasticizer
part, 0.5 part of Ca-3t as a lubricant and 0 part of stearic acid.
．． and 5 parts of R-9867 (manufactured by Dai-11 Seika Co., Ltd., Co-based pigment) as a pigment, were made into a 960 m1-wide sheet I with the thickness shown in the table below by the T-die molding method and the calendar molding method, respectively. and 11 and wound up into a roll. This was carried out using the apparatus shown in Figure 1 at a speed of 15 m/min and a temperature of 160 to 180°C.) 1 and 11
After polymerizing and thermo-compression bonding, the film was stretched at a stretching ratio of 250% and a stretching speed of 50 m/min to form a stretched film with a width of 945 mm. Each stretched film had holes of the size of rice grains per 100+s. The inspection results for the number of pieces are also listed in the table below.

The size of the foreign matter in the surface resin was 30 gm or more in diameter, but in the stretched film according to the method of the present invention, even if holes were formed in one sheet layer at the location where the U material was present, the other sheet layer The number of holes was kept within the passing line because the layer completely prevented them.

(Effects of the invention) 1. Since the hole punching defects during the production of H-stretched film are eliminated, the yield of the product is greatly improved.

2. Production of the original film in calendar molding and subsequent production of stretched film is facilitated, and the yield can be improved.

3. By appropriately combining different types of resin sheets or resin sheets with different thicknesses, a stretched film with a constant stretching ratio, taking advantage of the characteristics of each resin, and having an arbitrary thickness can be produced by spinning.

4. Each process of molding, polymerization, and stretching can be done in-line, streamlining the manufacturing process.

5. Conventionally, as the width of the original sheet spread, the defective rate due to holes increased, but with the method of the present invention, the defective rate does not increase that much even when the width increases, so it is particularly effective for wide sheets. be.

6. It is particularly useful because it can prevent holes in calender molding and sheet molding with high filler or pigment content, where there is a high chance of contamination by foreign matter.

[Brief explanation of the drawing]

The drawings are explanatory diagrams showing the polymerization process in the present invention. #4F Keijin Shin-Etsu Polymer Co., Ltd. Figure 1 6-piece sheet !

Claims (1)

[Claims] 1. After stacking and bonding two or more layers of formed original fabric,
A method for producing a stretched film, which comprises stretching.