JPH0218019A - Manufacture of film with calender - Google Patents

Abstract

PURPOSE:To reduce the number of occurrence of air mark and its length and consequently obtain film with favorable external appearance by a method wherein a cut-in is made in the direction intersecting the running direction of a sheet in the calendered synthetic resin sheet ahead the final bank of a calender. CONSTITUTION:Band- or rod-like raw material 10, which is uniformly kneaded with a mixer or the like, is fed to a calender so as to be calendered by a first roll 1 and a second roll 2 and passed through a third roll 3 and a fourth roll 4 and finally moved to a take-up roll 9. In the proximity of the surface of the third roll 3, a knife 5, which moves in the axial direction of the roll, is provided so as to make a cut-in in a calendered sheet, which moves on the surface of the third roll. The cut-in sheet enters between the third roll 3 and the fourth roll 4 with the rotation of the rolls so as to be calendered finally. At that time, the third bank 8 is formed and the sheet is guided to the take-up roll under the state that air bubbles contained in the sheet are vanished, resulting in obtaining film 11 with favorable external appearance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a method and apparatus for producing a synthetic resin film by calender molding. More specifically, the present invention relates to a method and apparatus for producing a synthetic resin film with good appearance by calender molding.

[Prior Art 1] A method of continuously manufacturing a film by rolling a synthetic resin using a calender is widely adopted.

Typically, the plasticized material supplied from a pregoo, Banbury, open mill, etc. is rolled through the opening of three or four calendar rolls to produce a film of desired thickness and width. Although the calender forming method simply rolls the material, it requires advanced operating techniques such as adjusting the temperature of each roll, controlling the rotation speed of the rolls, and adjusting the amount of roll banks accumulated between the rolls. technology has been developed.

One of the unresolved problems in calendar molding technology is air bubble entrainment. This is caused by air, etc., being drawn into the material during calendering, which involves repeated rolling.
Air marks remain until the end, roughening the surface of the film and damaging the appearance of the product. Air bubbles in the product film include moisture and volatile matter contained in the composite and resin composition, as well as air trapped during kneading and calendering. These bubbles are
As the temperature increases, the bubbles expand and occupy a large volume, becoming finely dispersed in the film and forming a fish-like shape. Otherwise, they become oval-shaped bubbles that remain in the product film and impair its appearance. These phenomena are particularly noticeable on thick materials, such as 0.3'
, 5 vs/(up to) thickness. In order to eliminate air bubbles that cause such a deterioration in film quality, various countermeasures have been considered in the past. For example, making the roll bank smaller, removing moisture from the synthetic resin material, and selecting materials with less moisture and volatile components. However, satisfactory results have not yet been obtained.

[Problem to be solved by the invention 1] The present invention is based on the method of forming a synthetic resin film by a calender molding method.
When making I-builds, the aim is to expel air bubbles that would impair the appearance of the product from the bank, and to prevent new air bubbles from being drawn in to produce a synthetic resin film with a good appearance.

Means for Solving Problem E 1 As a result of repeated research to solve the above problem, the present inventor found that
We have arrived at the present invention. That is, the gist of the present invention is that when producing a synthetic resin film by calender forming, cuts are made in the rolled synthetic resin sheet in a direction intersecting the sheet traveling direction before the final bank that is accumulated and formed between the calender rolls. Features a composite R & 84 fat film with a good appearance! ! and a calender that is equipped with a knife that is close to the surface of the penultimate calender roll and moves in the direction of the roll wheel to make cuts in the rolled synthetic resin.

The present invention will be explained in more detail below.

Synthesis 0 (fat is vinyl chloride?) suitable for the present invention, B51 (
Various thermoplastic synthetic resins including fats and rubbers, especially those that are elastic and have the properties of a plastic rubber that can be wrapped around a roll and are commonly calendered.

The calendar is also applicable to 3 rolls, V4 rolls and other various types of calendars.

In the case of a 4-roll calender, the film is rolled through the first and 20th lanes, the second and 30th lanes, and the third and 40th lanes to produce a film of the desired thickness and width. However, during this time, a bank is formed at each roll opening. In the present invention, the surface of the rolled synthetic resin sheet passing before the third and final bank, that is, the 30th-rule surface, is cut in a direction intersecting the sheet's traveling direction, thereby forming the final bank. By the way, the air bubbles that are mixed in and rolled up in the sheet are expelled in one season, and a synthetic resin film that does not contain air bubbles and has a good appearance is manufactured. In the case of a three-roll calender, cuts would be made in the surface of the sheet passing through the 20th roll.

Now, in order to make cuts in the rolled sheet, it is desirable to make deep cuts in the calender roll without damaging them, and it is most preferable to use a knife that moves in the direction of the roll wheel in close proximity to the roll surface. It does not necessarily have to be in the shape of a knife, as long as it can make a cut equivalent to that of the knife.For example, a roll with a spiral edge can be used. The knife may be made of various materials such as metal, wood, or bamboo, but since the synthetic resin sheet is soft, the knife does not need to be very sharp. A bamboo spatula or a wooden spatula may be used, and the number of knives may be one or two or more. In the case of one knife, a method in which the roll reciprocates from one end to the other is appropriate, and in the case of two or more knives, a method in which two or more knives repeatedly move left and right with respect to the direction of movement of the sheet is appropriate. However, the method is not limited to these methods, and when the knife is moved to make the cuts in this way, the cuts are made diagonally in the sheet. The synthetic resin sheet with the incisions made in this way is guided to the final roll interval, passes through the final rolling process, and then proceeds to the take-up roll.

The method of the present invention and! If Ii'lf is used to cut into a synthetic resin sheet, what type of work will improve its appearance?
Although it is not necessarily clear, the air bubbles that were caught up in the synthetic resin sheet before the incision was made are expelled when the final bank is formed, and new air bubbles are formed at the bank. Air entrainment does not occur. It has been known for a long time that the defoaming effect in a bank is greatly affected by the rotational state of the bank, but when the sheet with the notches flows into the bank, it acts to inhibit the rotation of the bank. Upper roll (for 4 calendars!jtJ
It is thought that the force from the 30-rule) is removed, a rotational state of the bank that cannot be obtained with conventional methods is obtained, and the defoaming effect is enhanced. Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic side view showing an embodiment of the present invention,
FIG. 2 is also a schematic perspective view.

First, the raw resin composition is uniformly kneaded using various mixers, etc., and then conveyed through a conveyor into a strip or V-shaped raw material 10.
is supplied to the calendar as

Next, it is rolled by IjtJ10-Rule 1 and V20-Rule 2, passes through TJFJ20-Rule 2 and 30th-Rule 3,
After passing through the 30th rule 3 and the 40th rule 4, it is finally transferred to the product production process from the take-up reroll 9. A first bank, a second bank 7, and a third bank 8 are formed between the first and 20th rules, between the second and 30th rules, and between the third and 40th rules, respectively. In the present invention, a knife 5 is provided that approaches the surface of the 30th rule 3 and moves in the direction of the roll wheel, and serves to make cuts in the rolled sheet moving on the surface of the 30th rule. As the rolls rotate, the incised sheet enters between the 30th-rule 3 and the 40th-rule 4, where it is subjected to final rolling.

Sono time 1: A Pt53 bank 8 is formed, but at this time, the sheet, including the air bubbles, disappears and is guided to a take-up roll, yielding a film 11 with a good appearance.

[Example 1] An example in which the present invention was applied to calender molding of a soft vinyl chloride film is shown below.

Composition pvc (p=aoo) 10 parts by weight DOP
2911 Epoxidized soybean oil 4 B a-Z n-based stabilizer 2 After kneading the vinyl chloride resin composition having the above composition using a Banbury mill roll and strainer, the roll temperature was adjusted using an inverted four-roll calender. Calendar molding was performed at 178-184°C, and the film thickness was 0.4 ml.
- I got the film La. During calendar molding, the number of air marks generated and the air mark length of a film formed by making incisions at a ratio of about one incision on the surface of No. 30 according to the present invention and a film in which no incisions were made at all. was measured, and the results are shown in Figure 3. In FIG. 3, the horizontal axis shows the air mark length, and the vertical axis shows the number of air marks generated per square inch.The films produced by the method of the present invention and the conventional method were both produced continuously.

[Effect of the invention 1] As is clear from FIG. 3, by making incisions in the film flowing into the final bank according to the present invention, the number of air marks and their length are improved, and a film with a good appearance can be obtained. It will be done.

[Brief explanation of the drawing]

Fig. f1 is a schematic side view showing an embodiment of the present invention, and Fig. 2 is a schematic perspective view. 1.2, 3.4 ... Calendar roll 5 ...
Knife 6? , 8 ... Bank 9
... Take-up roll 10 ... Resin composition 11
...Film Figure 3 shows the distribution of the number of air marks and the length of air marks for films produced by the conventional method and the present invention, where the horizontal axis represents the air mark length and the vertical axis represents the one-square theory. Shows the number of air marks generated per unit. Patent applicant Mitsubishi Kasei Vinyl Corporation

Claims (1)

[Claims] 1) When producing a synthetic resin film by calender molding, incisions are made in the rolled synthetic resin sheet in a direction intersecting the sheet traveling direction before the final bank that is accumulated and formed between the calender rolls. A method for producing a synthetic resin film with a good appearance, characterized by: 2) A calender equipped with a knife that is close to the surface of the penultimate calender roll and moves in the direction of the roll wheel to make cuts in the rolled synthetic resin.