Hoechst Aktiengesellschaft

American Hoechst Corporation

Hartmut Hensel

Hermann Dallmann

John D Gribbin

Werner Schaefer

Dieter Engel

Wolfgang Gawrisch

Peter Dinter

Siegfried Janocha

Gunther Crass

Werner Schafer

Theo Grosse-Kreul

Gerhard Stegmeier

Helmut Monzer, Deceased

Hermann Dallman

The biaxially stretch oriented, corona-treated polyester film, in particular polyethylene terephthalate film, is suitable as a base film for magnetic coatings. It exhibits the following features: at least one of its two surfaces exhibits a surface tension of at least 43 mN/m without an adhesion promoter having been added; the modulus of elasticity in the machine direction and/or transverse direction is greater than 5800 N/mm.sup.2 ; and the refractive index perpendicular to the film plane is less than or equal to 1.4900.

Polyester film having improved adhesion properties

A reclaimable polyester film is disclosed which comprises an oriented polyester film which has been coated with an adhesion-promoting coating. The coating is applied to the film as an aqueous dispersion and is dried and crosslinked by the application of heat. The coating is prepared by the free-radical emulsion polymerizable of the following components:

Reclaimable polyester film having adhesion-promoting coating

The invention concerns a polyester film with improved abrasion resistance, dimensional stability, drawability and slip properties. The film is characterized by the fact that it contains 0.005 to 5.0% by weight of organic, preferably hardened or crosslinked, particles with narrow particle size distribution in a range between 0.01 and 5 microns, as well as a nucleating agent in an amount from 0.01 to 10% by weight, both values related to the weight of the polymers which form the film.

Polyester film

Polyester film having improved abrasion resistance manufactured from

A coextruded, biaxially draw-oriented, multi-layer polyester film as a base film for magnetic tape is described, whose characteristics are that the total thickness of the multi-layer film is no more than 10 .mu.m, the surface roughness of the base film on the side intended for the application of an information-carrying coating has an R.sub.a value (DIN 4768) of less than or equal to 0.010 .mu.m and the surface roughness of the opposite side of the base film which is not intended for application of an information-carrying coating, has an R.sub.a value of greater than 0.010 .mu.m and that the film has an E-modulus in the machine direction of greater than or equal to 6500 N/mm.sup.2.

Multi-layer polyester film for magnetic tape

A biaxially oriented and heat set film having improved abrasion resistance is described, whose distinguishing characteristics are that it has a density of more than 1.38 g/cm.sup.3 and that the following relationship exists between the orientation birefringence (.DELTA.n), the reduced specific viscosity (RSV), and the temper peak (Tp) of the film:

Biaxially oriented film having high scratch and abrasion resistance

An abrasion-resistant, multilayer biaxially oriented carrier film for magnetic information media is described, composed of a base layer (A) comprising a thermoplastic polymer matrix of essentially linear aromatic polyester, containing finely distributed solid particles to improve the surface roughness which determines the slip properties of the film, and of at least one homopolyester cover layer (B) applied to one of the two surfaces of base layer (A). The characterizing features of the carrier film described lie in the fact that base layer (A) contains solid particles in an amount from 0.001 wt. % to 10 wt. % based on the weight of the polymer forming base layer (A), whereby the average particle size of the solid particles lies in the range from 0.3 to 20 microns, by the fact that cover layer (B) comprises a thermoplastic polymer matrix of essentially linear aromatic homopolyester, in which finely distributed solid particles in an amount from 0 to 10 wt. % based on the weight of the polymer forming cover layer (B) are embedded, whereby the solid particles have an average particle diameter of less than 0.3 micron, and by the fact that the layer thickness of cover layer (B) is a maximum of 40% of the layer thickness of base layer (A).

Abrasion-resistant polyester carrier film for magnetic information media

An abrasion-resistant, multilayer biaxially oriented carrier film for magnetic information media produced by coextrusion is described, said film being composed of a base layer (A) comprising a thermoplastic polymer matrix of essentially linear aromatic polyester, containing finely distributed solid particles to improve its surface roughness which determines the slip properties of the film, and of at least one cover layer (B) applied to one of the two surfaces of base layer (A). The characterizing features of the carrier film described consist in the fact that base layer (A) contains the solid particles in an an amount from 0.001 wt. % to 10 wt. %, based on the weight of the polymer forming base layer (A), whereby the average particle size of the solid particles lies in the range from 0.001 to 20 microns, by the fact that cover layer (B) comprises a thermoplastic polymer matrix of essentially linear aromatic copolyester, in which finely distributed solid particles are embedded in a quantity between 0 and 10 wt. %, based on the weight of the polymer forming cover layer (B), whereby the solid particles have an average particle diameter of less than 0.3 micron, and by the fact that the layer thickness of cover layer (B) is a maximum of 40% of the layer thickness of base layer (A).

Abrasion-resistant, copolyester carrier film for magnetic information

A biaxially oriented thermo-fixed multilayer film is described, consisting of thermoplastic polyester materials having different melting points and having an essentially scratch-free surface. The characterizing features of the multilayer film described consist in the fact that a cover layer of a polyester B is applied to at least one surface of a base layer of thermoplastic polyester A, said polyester B having a lower melting point than polyester A, and by the fact that no scratches longer than 3.0 mm and greater than 10 microns in cross-section are present on the surface of the cover layer.

Substantially scratch-free polyester multilayer film

Disclosed is a sealable, biaxially stretched polyethylene-coated polypropylene film, preferably manufactured as a flat film, which is not only extremely scratch-resistant but is also rapidly sealable, with good machine-running characteristics and high transparency. The polyethylene sealing layer has a scratch resistance of .ltoreq.50% gloss reduction, relative to an initial gloss of 100%, measured according to ASTM Standard Specification D673-70 (1976), and a density of .gtoreq.0.94 g/cm.sup.3, preferably of .gtoreq.0.95 g/cm.sup.3. Also disclosed is a process for the manufacture of the film, and the use of the film as an abrasion-resistant packaging material.

Sealable, biaxially stretched polypropylene film having high scratch

Disclosed is a film for use in the field of electrical insulation comprising a biaxially stretched rough polypropylene film comprising a plurality of first zones of high roughness, the first zones having a relatively high number of .alpha.-crystallites; and a plurality of second zones of substantially lesser roughness, the second zones having a substantially lesser number of .alpha.-crystallites than the first zones, the first zones being adjacent to the second zones and the adjacent first and second zones forming fine channels between each other. Also disclosed is a method for producing this film.

Growing community of inventors

Schlangenbad, Germany

Hartmut Hensel