A method for preparing an unsintered PTFE film capable of being continuously formed and with uniform density distribution and high density. The method for preparing the unsintered PTFE film includes filling a mixture obtained by adding a forming aid to PTFE fine powder in an extrusion forming die, extruding the filled mixture from the extrusion forming die to produce an extrusion forming body, rolling the extrusion forming body with a roll to produce a forming aid-removed film without the forming aid, and pinching the forming aid-removed film into a pinch roll made of a rubber roll formed by coating rubber on a metal shaft core at room temperature and compressing the forming aid-removed film so that thickness of the forming aid-removed film is reduced and density thereof is above 2.0 g/cm.sup.3.

A solar reactive mulch film comprising one or more layers of heat shrink material pre-strained at a predetermined temperature and tension. Immediately cooling the pre-strained layers retains molecular deformation stresses in the material which facilitate shrinkage but not expansion on exposure to solar radiation. The mulch film adapted to be laid over longitudinal growing beds and held tautly by burying its side edges in soil. Exposure of uncovered portions of film to solar radiation causes shrinkage in one or more directions whereby in combination with the weight of the soil holding it down, maintains tautness of the mulch over a growing period. Methods of manufacture and use of the same.

A solar reactive mulch film comprising one or more layers of heat shrink material pre-strained at a predetermined temperature and tension. Immediately cooling the pre-strained layers retains molecular deformation stresses in the material which facilitate shrinkage but not expansion on exposure to solar radiation. The mulch film adapted to be laid over longitudinal growing beds and held tautly by burying its side edges in soil. Exposure of uncovered portions of film to solar radiation causes shrinkage in one or more directions whereby in combination with the weight of the soil holding it down, maintains tautness of the mulch over a growing period. Methods of manufacture and use of the same.

An object of the present invention is to provide a stretchable polyester having shape followability and flexibility by elastic response and being able to suppress deterioration over time due to secondary crystallization. The present invention provides a stretchable polyester which is an aliphatic copolymer polyester containing two or more types of monomer units, wherein the stretchable polyester contains an α-form and an amorphous structure, and a degree of orientation determined by X-ray of the α-form is 50% or greater.

A device and a method for extending a film web along a longitudinal direction thereof include guiding the film web in a travel direction over several rollers, and extending the film web in at least one straining gap which is limited by at least two rollers operated with different circumferential speeds. The web is provided with a temperature gradient, which extends in the direction perpendicular relative to the longitudinal axis of the film web.

A device and a method for extending a film web along a longitudinal direction thereof include guiding the film web in a travel direction over several rollers, and extending the film web in at least one straining gap which is limited by at least two rollers operated with different circumferential speeds. The web is provided with a temperature gradient, which extends in the direction perpendicular relative to the longitudinal axis of the film web.

An improved control apparatus for producing plastic films and an associated improved method are distinguished, inter alia, by the following features: —the control apparatus has two stages or at least two stages, —the control apparatus comprises, for this purpose, a sensor module and/or a sensor model and a process module and/or a process model, —the machine-dependent sensor module and/or sensor model and the production-dependent process module and/or process model are linked or can be linked to one another via production variables, —adjustable machine variables are connected or linked to plant production variables via the sensor module and/or the sensor model.

An improved control apparatus for producing plastic films and an associated improved method are distinguished, inter alia, by the following features: —the control apparatus has two stages or at least two stages, —the control apparatus comprises, for this purpose, a sensor module and/or a sensor model and a process module and/or a process model, —the machine-dependent sensor module and/or sensor model and the production-dependent process module and/or process model are linked or can be linked to one another via production variables, —adjustable machine variables are connected or linked to plant production variables via the sensor module and/or the sensor model.

There is provided a touch fastener that has high followability to the relative movement of portions to be engaged and does not easily separate from a mating member, and thus is usable in a wider range of applications. In the touch fastener, all the elements, that is, first strands, second strands, and engagement elements are formed of a thermoplastic elastomer. Further, the plurality of first strands and the plurality of second strands are disposed to intersect with each other, and consequently, hole portions each surrounded by the two adjacent first strands and the two adjacent second strands are provided. Accordingly, it has a high elastic function, easily stretches, and has high followability to the relative movement of portions to be engaged.

A solar reactive mulch film comprising one or more layers of heat shrink material pre-strained at a predetermined temperature and tension. Immediately cooling the pre-strained layers retains molecular deformation stresses in the material which facilitate shrinkage but not expansion on exposure to solar radiation. The mulch film adapted to be laid over longitudinal growing beds and held tautly by burying its side edges in soil. Exposure of uncovered portions of film to solar radiation causes shrinkage in one or more directions whereby in combination with the weight of the soil holding it down, maintains tautness of the mulch over a growing period. Methods of manufacture and use of the same.