Hoechst Aktiengesellschaft

Siegfried Janocha

Lothar Bothe

Guenther Crass

Klaus Hoheisel

Gunther Crass

Gunter Schloegl

Hans Strutzel

Wolfgang Dietz

Dieter Gebhardt

Hermann Dallmann

Hartmut Hensel

Walter Seifried

Harald Mueller

Werner Schaefer

Ulrich Bollert

Manfred Unger

Walter Siefried

Gunter Schloegi

Gerhard Stegmeier

G/u/ Nther Crass

Gisbert Bammert

Harmut Hensel

A process is described to produce ultra thin biaxially stretched film made of thermoplastic where at least two film webs are superimposed and stretched together in both the longitudinal and transverse directions. The film webs are subjected to a heat treatment before the first draw step. After stretching, the film webs are separated again from each other.

Process to produce thin film

A device for smoothing out the thickness of a sheet of thermoplastic material which includes a sheet die and a heating device which is integrated with the upper die lip of the sheet die. The heating device includes a hollow box filled with a liquid and a bar which projects laterally beyond the endfaces of the hollow box. The inlet and outlet openings of the bar in the hollow box are sealed. Arranged on the underside of the bar are small hot plates which are electrically heated. The liquid in the hollow box serves as a heat transfer medium and typically is an oil having a boiling point higher than 280.degree. C. The thickness profile of the extruded sheet is controlled, on the one hand, via controlling elements and, on the other hand, remaining thick and/or thin points of the sheet profile are smoothed by the bar of the heating device, in which the bar is progressively moved transversely with respect to the running direction of the sheet across the sheet width with the aid of a motor into a position in which the small hot plates are aligned with the thick/thin points to be smoothed. The corresponding thick/thin points of the sheet are smoothed by exposing the small hot plates to different temperatures or heating powers.

Device for smoothing out the thickness of a sheet

A biaxially stretch-oriented film, suitable for the process of transfer metallizing, which comprises a base layer coextruded with covering layers on either side thereof and comprising an inert admixture is disclosed. The three layers are formed of polyolefin and the base layer comprises an additive which migrates from the base layer into the covering layers. The base layer contains the inert admixture in the form of finely divided particles, which partially protrude from the base layer and are completely enveloped by the covering layers. At least one of the two outer surfaces of the covering layers displays, at least in partial areas, an increased roughness attributable to the particles protruding from the base layer.

Film for transfer metallizing

Disclosed is an opaque, biaxially stretch-oriented, polyolefinic multilayered film comprising an opaque core layer and two transparent top layers. The core layer contains a mixture of

Opaque multilayered film having an inherent resistance to delamination

An opaque polyolefin film having a base layer composed essentially of propylene polymers and having sealing layers present on both sides, composed essentially of sealable olefin polymers, is disclosed. From about 0.2% to 1.5% by weight, relative to the layer of polydialkylsiloxane is incorporated in one of the two sealing layers, and this layer has not been subjected to corona treatment. The other sealing layer has been subjected to corona treatment and has polydialkylsiloxane, not incorporated, but present on the outer surface of this layer, the polydialkylsiloxane having been transferred to this layer by contact between the sealing layer in which polydialkylsiloxane is incorporated. The relative polydialkylsiloxane occupancy of this layer, which is determined by means of ESCA spectroscopy, is not more than 15. The three-layer opaque polyolefin film is prepared by the coextrusion process. It is particularly suitable for use as a packaging film on high-speed packaging machines.

Biaxially oriented opaque polyolefin multi-layer film

For packaging purposes, metallized multilayer films containing a biaxially oriented polypropylene film as a base layer should have high scratch resistance, good heat-sealing properties, such as low heat-sealing temperature, attractive visual properties, such as high metallic luster, excellent metallizability of the base layer or of a covering layer, and also good processing properties during metallization, printing, slitting, and during processing on fast-running packaging machines. This requirement profile is fulfilled by a multilayer film of asymmetric structure containing a biaxially oriented base layer 4 composed of polypropylene, a heat-sealing layer 3 which contains an additive combination composed of pigment in platelet form and siloxane and which is optionally modified by an addition of polypropylene and a hydrocarbon resin, and of a corona-treated polypropylene covering layer 2 which is not capable of being heat-sealed. A corona-treated, heat-sealable copolymer may also be used as the covering layer 2, instead of a covering layer 2 composed of non-heat-sealable polypropylene. The covering layer 2 can also be omitted; in that case the surface of the base layer 4 is metallized. Tubular bags, jackets, containers of various shape for packaging foodstuffs, including the vacuum packaging of foodstuffs, are manufactured from this multilayer film.

Multilayer film containing a biaxially oriented polypropylene film

Described is an opaque, biaxially draw-oriented thermoplastic film for candy twist wrapping. The film is formed from a polymer mixture comprising from about 40 to about 60% by weight of polypropylene and from about 35 to about 55% by weight of polystyrene, relative to the total weight of the mixture. The mixture additionally comprises from about 5 to about 15% by weight of a filler material, relative to the total weight of the mixture.

Opaque film for candy twist wrapping

This invention relates to a biaxially or multi-axially oriented, heat set film, which has on its surface numerous unevenesses, which comprise indentations around a protrusion. The protrusions comprise crosslinked or hardened organic particles having an average particle size of from 0.01 to 5.0 microns and having a narrow particle size distribution. The film surface has a mean surface roughness value Ra of from 0.005 to 0.10 micron.

Oriented plastic film having specific surface topography

A sealable, transparent polyolefinic multilayer film composed of a polypropylene base layer, a non-sealable surface layer, and a sealable surface layer, and process therefor. The sealable surface layer has a low minimum sealing temperature and is made from a copolymer of propylene and ethylene or butene-1 units and/or a terpolymer of ethylene, propylene and butene-1 units. The non-sealable layer is a combination of a propylene homopolymer, a slip agent, and an anti-blocking agent. The process includes coextruding the three layers, biaxially stretching the coextruded film, and subjecting the non-sealable layer to a corona-discharge treatment.

Sealable, transparent polyolefinic multilayer film

A coextruded multi-layer opaque film which has been biaxially oriented by stretching in the longitudinal direction and transverse direction at selected temperatures and with selected stretch ratios, and a method for producing the film. The film has a base layer of polypropylene or a copolymer thereof, and fillers. Its density is 0.4 to 0.6 g/cm.sup.3, the amount of filler, based on the mixture of polypropylene and filler, is 16 to 30% by weight, and the particles of the filler employed have a mean size of 2 to 5 .mu.m. Because of its reduced tendency to recover after folding, the film is particularly suitable for packaging purposes. One or more surface layers can be applied on either or both sides of the base layer.

Multi-layer opaque low density film

A sealable, opaque polyolefinic multilayer film composed of a polypropylene base layer, a non-sealable surface layer, and a sealable surface layer, and process therefor. The sealable surface layer has a low minimum sealing temperature and is made from a copolymer of propylene and ethylene or butene-1 units and/or a terpolymer of ethylene, propylene and butene-1 units. The non-sealable layer is a combination of a propylene homopolymer and a slip agent. The base layer contains an additive which is incompatible with polypropylene. The process includes stretching of the film, and during the stretching step, the polymer matrix is torn open around the additive particles to form vacuoles which give the base layer a degree of opacity.

Sealable, opaque polyolefinic multilayer film and process therefor

Disclosed is a sealable transparent multilayer film, comprising: a base layer comprised of a propylene polymer and at least one sealable layer comprised of a combination of:

Sealable multilayer film for packaging purposes

A sealable, transparent, polyolefinic multilayer film comprises a base layer formed of a polypropylene polymer and at least one sealable layer, which contains a propylene copolymer, a low-molecular weight resin, a polypropylene homopolymer and a polydiorganosiloxane. The sealing layer is comprised of a combination of

Sealable polyolefinic 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 an opaque film of thermoplastic organic material which has been oriented by biaxial stretching, comprising a base layer of a polymer or copolymer of an .alpha.-olefin having 2 to 6 carbon atoms containing between about 1 and 25 percent by weight, calculated on the weight of the polymer, of finely distributed solid particles ranging in size from about 0.2 to 20 .mu.m, and carried on at least one surface of the base layer, a heat-sealable layer comprising a copolymer of propylene with ethylene, a copolymer of propylene with butene, or a terpolymer of propylene with ethylene and a further .alpha.-olefin having from 4 to 10 carbon atoms. Also disclosed are a method of making this film and a package made therefrom.

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Wiesbaden, Germany

Siegfried Janocha