DD224538A1 - METHOD FOR PRODUCING CASTING FILMS - Google Patents

Abstract

Cast films based on ethylene copolymers are to be developed, which have excellent dielectric properties and good strength. These requirements are solved by copolymerization of norbornene and ethylene in cyclic hydrocarbons or cyclic hydrocarbon-containing solvent mixtures and direct processing of the resulting polymer solution to the cast film. Cast films made of norbornene-ethylene copolymers can be used as temperature-resistant electrical insulation film, as Assiettenfolie and as packaging material.

Description

.YSB Leuna-Werke Leuna, the

"Walter Ulbricht ¹ '

LP 83 159

Title of the invention

Process for producing cast films

Field of application of the invention

The invention relates to the production of cast films which have excellent dielectric properties and good strength and are used as temperature-resistant electrical insulation films.

Characteristic of the known technical solutions

It is known to process polymer solutions by cast film into cast films which are suitable as electrical insulation films and heat-resistant packaging material. For polysylene films, the upper use temperature is 360 K. It is also known cast films of polyphenylene oxide in the Elektroisolationsgebiet to 380 K (JP-PS 7125628) and polycarbonate and polyethylene terephthalate to 400 K. (H. Hofmeier, Angew ), 645? Ullmann, Encyclopaedia 4th ed. 3d. 11 p.683). For a-

Set temperatures up to 420 K are cast films based on polyvinyl fluoride. (U.S. Patent No. 679,761, U.S. Patent No. 1,154,939, U.S. Patent No. 1,153,885) or aromatic polysulfone ethers (DS-OS 2141913, Japanese Patent No. 7113839). A heat resistance up to 450 K has polyhydantoin-based cast films (Kunststoff-Berater f1972) 12, 643-644), polyamideimides and polyesterimides (D. Loncrini, J. Polymer Sci. A1, 4 (1966), 1531).

Object of the invention

The aim of the invention are cast films which are suitable as temperature-resistant electrical insulation foils.

Explanation of the essence of the invention

The object of the invention is to develop a process for the production of cast films based on ethylene copolymers of high temperature resistance. This object is achieved by a process for the production of cast films from temperature-resistant ethylene copolymers, wherein according to the invention resulting from the copolymerization of urorbornene with ethylene in cyclic hydrocarbons or cyclic hydrocarbon solvent mixtures resulting polymer solutions are further processed directly to the cast film.

Cyclooliphatic solvents such as cyclopentane, cyclohezane, methylcyclohexyl or urorbornene or aromatic solvents such as benzene, toluene or xylene are advantageously used as solvents in the copolymerization, or solvent mixtures consisting of aliphatic hydrocarbons and cycloaliphatic and / or aromatic hydrocarbons are used.

χ. The copolymerization is initiated by organometallic. To set the required viscosity of the Pilmgießlosung the polymerization is advantageously at Um-

X mixed catalysts

sätaen preferably stopped in the range of 7 to 15 % by the addition of alcohols.

The film casting of the polymer solutions can be carried out by the usual methods. For a slight detachment of the cast film from the substrate is a plastic coating of the substrate z.3. with cellulose triacetate, cheap.

Pure casting films with very low solvent retention after drying are particularly advantageous for cycloaliphatic or cycloaliphatic-containing solvent mixtures. The copolymerization initiated by highly active mixed catalysts is carried out under conditions such that copolymers with glass temperatures preferably in the range of 410 to 430 K and intrinsic viscosities in trichlorobenzene at 408 K, preferably in the range of 0.50 to 0.90 Cdl / g) are formed. These parameters are a prerequisite for good film quality after film casting.

The cast films can be used as slektroisolationsfolien, as Assiettenfolien or as sterilizable packaging material.

Exemplary embodiments Example 1

In a 1.5 1 polymerization reactor with stirrer, metering device and inert gas flushing 150 ml of a 80 % Sbrbornen containing eorbornene heptane solution and 850 ml of cyclohexane are introduced, the mixture saturated with ethylene at 290 K and by addition of a highly active organometallic mixed catalyst polymerization initiated. ITaeh. a recording of 20 1 of ethylene, the polymerization is stopped by the addition of 1 ml of butanol. The polymer solution is cast on a cellulosetriasetate-coated gas plate into a cast film. Bach separation and drying, the cast film has the following properties;

Thickness: 0.02 mm

ρ Tensile strength: 47 H / mm DK (50 Hz): 2.32

DK (10 ⁶ Hz): 2.27

tan -S (100 Hz): 9.0. 10 " ⁴ glass transition temperature: 411 K intrinsic viscosity in trichlorobenzene at 408 K: 0.65 dl / g

Example 2

In the polymerization after. Example 1 is used instead of 850 ml of cyclohexane 900 ml of benzene as a cyclic solvent. The resulting cast film (0.04 mm) has the following properties: Tensile strength: 45 iJ / mm DK (50 Hz): 2.34 kD (10 ⁶ Hz): 2.29 tan ο (100 Hz): 8.5. 10 ~ ⁴ glass transition temperature: 413 K intrinsic viscosity in trichlorobenzene at 408 K: 0.72 dl / g

Example 3. '

In the polymerization according to Example 1, instead of 850 ml of cycloheethane, an 80% strength solution of eorbornene in cyclohexyl is used. The resulting cast film has the following properties:

DK (50 Hz): 2.33

DK (10 ⁶ Hz): 2.28

tan f (100 Hz): 9.2. 1θ " ⁴ glass transition temperature: 427 K limiting viscosity in trichlorobenzene at 408 K: 0.85 dl / g thickness: 0.05 mm

Example 4

In a 4 ta "'- polymerization reactor with stirrer, metering device and inert gas flushing 0.4 m of a 75 $ eorbornene gasoline solution and 2.2 m of a mixture of 50 % cyclohexane and 50 % gasoline are introduced, the mixture with ethylene at 280 K is saturated and the polymerization is initiated by metering in a highly active organometallic mixed catalyst, after uptake of 60 m of ethylene, the polymerization is stopped by the addition of 4 l of propanol.The polymer solution is processed directly on a drum-type casting machine of known type The thick cast film has the following properties:

2 Tensile strength: 46! T / mm

DK (50 Hz): 2.31 ".

DK (10 ⁶ Hz): 2.26

tan cT (100 Hz): 1.2. 10 ~ ⁵

Glass transition temperature: 414 K

Intrinsic viscosity in trichlorobenzene at 408 K: 0.72 dl / g

Claims (2)

• Claim 1. A process for the production of cast films from temperature-resistant Bthylen-iCopolymeren, characterized in that the polymer solutions resulting from the copolymerization of JTorbornen with ethylene in cyclic Kohlenv / asserstoffen or cyclic hydrocarbons solvent mixtures are processed directly to the cast film · 2. The method according to item 1, characterized in that the polymer solution contains cyclohexane as a solvent component.