JP2640189B2 - Casting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of casting a polymer solution on a metal support to form a film, drying the film, peeling the film from the support, and further drying the film. The present invention relates to a rolled film forming method.

[0002]

2. Description of the Related Art A polymer solution is cast on a metal support,
After the film is formed, the film is dried, peeled off from the support, and further post-dried.
After casting a dope in which cellulose acetate was dissolved in a methylene chloride-methylene alcohol mixed solvent to form a film,
Dry and take care when peeling off from the support,
In order not to impair the flatness and transparency of the film at the time of peeling, it has been extremely difficult to improve the film forming speed.
In order to solve this problem, as a solvent for dope, methylene chloride 80-93% ethyl alcohol 2-7%,
A method using a mixed solvent comprising 5 to 13% of n-butyl alcohol (see Japanese Patent Publication No. 45-9074), a method in which the solvent for dope is methylene chloride and one having 1 to 2 carbon atoms.
(Japanese Patent Application Laid-Open No. 54-48862) using a solvent containing 13 to 30% by weight of an alcohol having 1 to 2 carbon atoms.

[0003]

However, when it is not desirable to use a plurality of solvents to promote peeling as described above, or when it is difficult to select an appropriate solvent as described above, for example, when a solute is used, In the case where is polycarbonate, a measure was desired. An object of the present invention is to solve the above-mentioned problems and to provide a casting film forming method which does not impair the flatness under the conditions of the volatile components to be stripped and the temperature at the stripping without depending on the selection of the solvent.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to provide a thermo-electric device.
After casting the solution of the plastic polymer compound on a metal support to form a film, drying, peeling off from the support, and further performing post-drying, The solvent content at the time of removal is set to 10 to 30% by weight on a dry basis, and the surface temperature of the support at the peeled portion is 20 ° C or less .
A casting film forming method characterized by maintaining the temperature at 5 ° C. or higher.

[0005] In the case of a casting film, when the casting film is peeled off from the support (band and drum), if the casting film has a strong adhesive force to the support, step-like unevenness may occur at the time of peeling. become. Further, when the time until the separation after casting is shortened, the film is weakened due to the small amount of evaporation of the solvent, and the film is stretched at the time of separation to cause unevenness in the width direction. Generally, the volatile content of the film and the peeling load from the support in the solution casting have shapes as shown in FIG. In this case, if the volatile content is higher, the film may be weakly stretched or sagged, and in some cases, a peeling phenomenon that a part of the film remains on the support may occur. In other words, if the solvent content at the time of peeling exceeds 30% by dry weight, the peeling load becomes large, and there is a risk of occurrence of step-like unevenness at the time of peeling, and the peeling load decreases at 40% by dry weight. However, the elasticity of the film becomes weak, and elongation occurs at the time of peeling, resulting in unevenness in the width direction. When the content of the solvent is 10% on a dry basis, the film is spontaneously peeled off, and there is a risk of damaging the film. It is preferably 15 to 27% by weight on a dry weight basis. In the present invention, the dry basis is (solvent amount / dry solid content) × 100%.
14. The surface temperature of the support at the peeled portion is 20 ° C. or less .
Maintaining the temperature at 5 ° C. or higher is a means for weakening the adhesive force of the film to the support at the time of peeling.
At a temperature of 0 ° C., the releasability is poor and step-like unevenness occurs on the film. At 12 ° C., dew condensation occurs on the surface of the support and brushing of the film surface becomes cloudy, which is not preferable.

[0006]

EXAMPLES (Example-1) Polycarbonate concentration 1
7.5% by weight of a dope is cast on a band support, and when the solvent content at the time of peeling is set to 19% by weight on a dry basis, there is no resistance when peeling off from the support and there is no unevenness. Film.

(Comparative Example 1) The amount of the solvent contained was 3 on a dry basis.
In the case of 3% by weight, peeling resistance was present, and unevenness in the width direction of the film occurred. In addition, when the dry weight was 10% by weight or less, the film spontaneously peeled off from the support, causing troubles during production.

(Example 2) When the temperature of the support at the peeling portion of the support was set to 15.5 ° C., the releasability was improved.

(Comparative Example 2) When the temperature of the support at the peeling portion was 22 ° C., the peelability was poor and step-like unevenness was caused. 12 ° C
In the following, dew condensation occurred on the surface of the support, brushing of the film surface became cloudy, and the surface condition of the film deteriorated.

[0010]

According to the casting film forming method of the present invention, it is possible to form a uniform planar film without impairing the flatness depending on the amount of the solvent contained at the time of stripping and the temperature condition at the time of stripping without selecting the solvent. It could be manufactured.

[Brief description of the drawings]

FIG. 1 is a graph of a peeling load with respect to a dry amount (% by weight) of a solvent content when a dope is peeled off.

Claims (1)

(57) [Claims] 1. A casting method wherein a solution of a thermoplastic polymer compound is cast on a metal support to form a film, dried, peeled off from the support, and further post-dried. In the film forming method, the content of the solvent at the time of peeling is adjusted to 10 to 30% by weight on a dry basis.
And the surface temperature of the support at the peeled portion is 20
A casting film forming method, wherein the temperature is maintained at 15.5 ° C. or lower.