JPS58145418A - Manufacture of amorphous polyester film - Google Patents

Abstract

PURPOSE:To obtain the titled film which is free from an irregular unevenness and has a good uniformity, by adding the kind of a specified aliphatic monocarboxylic acid, etc. to a polyester and melting, then, cooling, sloidifying it by contacting it to a moving cooling surface and preventting an accumulation of a low molecular weight substance to a cooling apparatus. CONSTITUTION:When an amorphous polyester film is manufactured by extruding a molten polyester (e.g.; polyethylene terephthalate, etc.) from a die orifice in filmy form and contacting it to a moving cooling surface, performing cooling and solidifying, a desired film is obtained by adding one or more kinds of a C8- 32 aliphatic monocarboxylic acid (e.g.; a stearic acid, etc.), its ester, its metal salt and a liquid paraffin etc. to the polyester and reducing an accumulation of a low molecular weight substance of the polyester to the moving cooling surface.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an amorphous polyester film OII.
IiK is brought into close contact with a moving cooling surface and cooled and solidified.
A method for producing polyester films that reduces the deposition of low molecular weight substances from both uncooled polymer surfaces onto cooled surfaces.

When melt-extruding a crystalline thermoplastic resin such as polyethylene terephthalate, it is necessary to rapidly cool the molten polymer below its glass transition temperature to minimize crystallization. Excessive crystallization occurs in the polyester film, mI1-17', :L, -1)110F#Al11I*f￥ For example, it interferes with the stretching orientation and causes haze and thickness unevenness in the oriented product. . The polyester film is then rapidly solidified by pouring the molten polymer onto a cold moving surface such as a rotating drum.

However, under high temperatures, some polymer films tend to have low molecular weight substances that precipitate on the film surface and sublimate from the film surface, so when the film is brought into close contact with a moving cooling surface,
Low molecular weight substances adhere to and contaminate the moving cooling surface. This low molecular weight substance may be contained in the polymer, or may be hydrolyzed by surrounding moisture during melting.

When low-molecular-weight substances adhere and accumulate on the moving cooling surface, irregular irregularities occur on the cooling surface, causing irregular irregularities and non-uniform physical properties on the surface of the product film. In addition, part of the deposits that caused a decrease in cooling efficiency peeled off from the moving cooling surface and adhered to the film, causing surface defects on the film and reducing product value. Furthermore, this deposit becomes increasingly difficult to remove as the operation continues because the hot sheet burns it onto the cooling surface. This low molecular weight sublimate deposits not only on the moving cooling surface but also on the linear electrode pattern in the electrostatic adhesion method that is commonly used to improve the adhesion between the cooling surface and the film. , which significantly reduces the effectiveness of electrostatic adhesion. In order to remove this deposit, conventional technology requires stopping the equipment and cleaning the surface.
This was causing a decline in productivity.

The present inventors have completed the present invention as a result of intensive studies regarding such problems.

That is, in the present invention, when producing an amorphous polyester film in which molten polyester is extruded into a film through a die orifice, brought into close contact with a moving cooling surface, and solidified by cooling, an aliphatic monocarboxylic acid having t to 3 carbon atoms is added to the polyester. , its ester, its metal salt, and liquid paraffin are added to reduce the deposition of low molecular weight substances of the polyester on the moving cooling surface. exists in

The present invention will be explained in more detail below.

The polyester used in the present invention refers to a polyester obtained using terephthalic acid or its alkyl ester and ethylene glycol as main starting materials, but other third components may be used as part of the raw materials. As the third component, isophthalic acid as an aromatic dicarboxylic acid component,
Naphthalene dicarboxylic acid or their alkyl esters, etc., two or more types, as glycol components, propylene glycol, tetramethylene glycol,
One or more polyalkylene glycols such as polyethylene glycol can be used. In any case, the polyester of the present invention refers to a polyester in which most of the repeating structural units and CrOx are polyethylene terephthalate units.

Examples of the aliphatic monocarboxylic acid having a carbon number of t-JJ used in the present invention include capric myristic acid, stearic acid, hehenic acid, and montanic acid. Examples of the ester include glycerol stearate and ethylene glycol mono- or diester of montanic acid. Examples of the metal salt include calcium stearate, magnesium stearate, sodium stearate, zinc stearate, and calcium phosphate. Alkaline earth metal salts or alkali salts are particularly preferred.

As the liquid paraffin, it is possible to use paraffin, which is liquid at room temperature and is represented by CnH@n+.

The amount of such compound added is / 0 with respect to polyester resin.
~1000 ppm, preferably go-ss.

It is ppm. If the amount added is less than /Oppm, the effect of reducing the accumulation of low molecular weight sublimate due to decomposition of polyester on the moving cooling surface cannot be obtained.

Even if it exceeds 1000 ppm, no further O Kaito effect can be obtained, and on the contrary, the resulting polyester film may have lower viscosity, coloration, and lower transparency, which is not preferable.

Addition of such compounds to the polyester resin can be carried out at any stage prior to melt extruding the polyester resin. For example, the compound added during the polycondensation reaction when producing polyester resin can be directly added to polyester resin pellets and adhered to the pellet surface and melt-extruded, or the pellets and compound can be melted together in advance using an extruder. By mixing, a so-called masterbatch containing a highly concentrated compound can be produced, and this and pellets not containing the compound can be blended to a predetermined concentration and extruded.

In particular, it is more effective to add it after polyester polymerization and before extrusion.

Melt extrusion is carried out at a temperature range of 0 to 310°C. The melt extruded into a film from the die orifice is heated to 30 to 70°C on its surface. It is placed in close contact with the SM cooling surface where the temperature is maintained, and is cooled and solidified. At that time, means such as electrostatic adhesion method can be used to improve adhesion.

The present invention will be explained below with reference to Examples. In addition, "part" or "chi" in the examples are both "Arashi m part" and "Denyu chi"
It is.

Example 1 A polyethylene terephthalate resin having an intrinsic viscosity of 0.66 was vacuum-dried at IBO° C. for 6 hours. Add 00 ppm of magnesium stearate to the dried resin, extrude it through a slit die using an extruder, and
It is cooled and solidified on a rotating cooling drum kept at ℃ to a thickness of 270℃.
A micron amorphous solid fiber film was obtained. /,
After running for hours, the scratched surface of the cooling roll was still clean and no low molecular weight compounds were observed.

Example 1/part of ethylene glycol distearate was added to 100 parts of polyethylene terephthalate resin with an intrinsic viscosity of 0.64 that had been vacuum-dried at 140°C for 6 hours, and -
Pellets of 1% master patch of ethylene glycol distearate were prepared by melt-kneading using an extruder at to°C. Next, 5 parts of the master patch pellets and 93 parts of polyethylene terephthalate resin were blended to form 7 parts of the master patch pellets.
Vacuum drying was performed at 60°C for 6 hours. This dry resin was processed in the same manner as in Example 1 to obtain an amorphous polyester film with a thickness of 210 μm using an extruder. Even after hours of operation, the polished surface of the cooling roll was still clean and low molecular weight compounds No adhesion was observed.

Example 3 The state of attachment of low-molecular compounds to the moving cooling surface was observed in the same manner as in Example 1 except that liquid paraffin was used instead of magnesium stearate. No adhesion was observed even after /,j hours of operation.

Comparative Example 1 The same polyethylene terephthalate resin as that used in Example 1 was dried at ITO°C for 6 hours in the same manner as in Example 1, and then melt-extruded using an extruder to give a thickness of 1.
A 0μ amorphous polyester film was obtained. After one hour of operation, the polished surface of the cooling surface was heavily streaked with a coating of low molecular weight compounds.

Applicant Diafoil Co., Ltd. Agent Patent attorney Hase Yo - Others 14 Procedural amendment (H type) % type % 1 Indication of case 1982 Patent Application No. 27777 2 Title of invention Process for manufacturing amorphous polyester film 3 Relationship with the case of the person making the amendment Applicant Diafoil Co., Ltd. 4 Agent 5 Mitsubishi Chemical Industries, Ltd., 2-5-2 Marunouchi, Chiyoda-ku, Tokyo 100 Date of amendment order May 25, 1980 ( Date of shipment)
6 Subject of amendment Application and specification 7 Contents of amendment

Claims (1)

[Claims] 11) Extrude the molten polyester through the die orifice onto the film # and onto the moving cooling surface El! When producing an amorphous polyester film which is coated with F and cooled and solidified, one or more selected from carbon I#t-J JC) aliphatic monocarboxylic acids, esters thereof, metal salts thereof and liquid paraffin is added to the polyester. A method for producing an amorphous polyester film, characterized in that the deposition of low molecular weight polyester substances on a moving cooling surface is reduced.