The present invention discloses a method and device of film stepless biaxial tension based on saddle-shaped surface transition. In the film surface biaxial stretching process, with the lateral and longitudinal tensile forces applied to a different tangent plane, the film is subjected to smooth transition in a three-dimensional space from a narrow plane via a saddle-shaped surface to a wide plane, with the thickness uniformity of the biaxial tension film regulated by controlling the shape of the saddle-shaped surface; the device comprises a herringbone wheel unit and a parallel wheel unit, the angle between the two lateral tension wheels in the herringbone wheel unit being adjustable, the two longitudinal tension wheels in the parallel wheel unit being arranged in parallel; the lateral tension of the film is achieved by the rotation of the lateral tension wheel, and the longitudinal tension of the film is achieved by the linear velocity difference between the lateral tension wheel and the longitudinal tension wheel. The present invention, adopting the binding wheel structure, effectively uses the saddle-shaped surface to regulate the bowing phenomenon, and reduces the contact surface between the film and the tension element, thus preventing the surface performance from deteriorating by friction, which is advantageous for improving the thickness uniformity of the film product.

A film stretching plant is described, which comprises a furnace (3), which consists of several treatment zones (1, 1a) which each respectively comprise a ventilation unit (2). The film (4) is suppliable to the furnace (3) through a film inlet region (5) and is thermally treatable zone-wise in the treatment zones (1, 1a). The treatment fluid (6) supplied to the film stretching plant flows over the film (4) on its upper surface and its lower surface in the treatment zones (1, 1a). In the film stretching plant according to the invention, the treatment fluid (6) is circulatable in the respective treatment zone (1, a) by its associated respective ventilation unit (2) for the thermal treatment of the film (4), and a portion (6a) of the treatment fluid (6) is conveyed from the respective treatment zone (1) to the process-technically following treatment zone (1a). This portion (6a) of the treatment fluid (6) that is conveyed into the following treatment zone (1a) is conveyed decoupled from the passage region of the film (4) in the treatment zones (1, 1a), wherein the respective treatment zones (1, 1a) are equipped with a heat exchanger, by means of which the portion (6a) of the treatment fluid (6) conveyed to it is adaptable to the temperature that is process-technically required in this treatment zone for the thermal treatment of the film (4).

A gripper is disclosed for a draping frame having a gripper chassis and at least two opposing mutually movable gripper jaw elements for gripping a film element. The gripper jaw elements are provided on a gripper head part of the gripper. The gripper head part of the gripper is movably mounted, at least with one degree of freedom, relative to the gripper chassis.

A gripper is disclosed for a draping frame having a gripper chassis and at least two opposing mutually movable gripper jaw elements for gripping a film element. The gripper jaw elements are provided on a gripper head part of the gripper. The gripper head part of the gripper is movably mounted, at least with one degree of freedom, relative to the gripper chassis.

A link mechanism 11 according to an embodiment includes a base member 25, an outer rail holder 24a provided on one end side of the base member 25 and including guide rollers 41 and 42 moving along a rail 14, an inner rail holder 24b provided on the other end side of the base member 25 and including guide rollers 41 and 42 moving along another rail 13 provided on an inner side of the rail 14, link plates 22 and 23 each having one end rotatably coupled to the outer rail holder 24a and the other end rotatably coupled to another link mechanism 11, and a clip 21 provided on the one end side of the base member 25 where the outer rail holder 24a is provided and configured to grip the film. The outer rail holder 24a includes a roller cover 50 configured to cover at least one of the guide rollers 41 and 42 moving along the rail 14.

A link mechanism 11 constituting a link device used in a stretching machine configured to stretch a film includes a pair of rail holders 24. Each of the rail holders 24 include guide rollers 51a, 51b, 52a, and 52b having openings on both end sides in an axial direction and moving while rotating, hollow shafts 54 and 55 having openings on both end sides in a direction along the axial direction, one sides being fixed to the rail holders 24 and the other sides being inserted into the guide rollers 51a, 51b, 52a, and 52b, bearings 56a, 56b, 57a, and 57b interposed between the guide rollers 51a, 51b, 52a, and 52b and the hollow shafts 54 and 55 and configured to rotatably support the guide rollers 51a, 51b, 52a, and 52b, and flanged shafts 58 and 59 having shaft portions 58a and 59a inserted into the hollow shafts 54 and 55 and flanges 58b and 59b supporting the bearings 56a and 57a.

Link devices include a plurality of link mechanisms which are coupled so as to form an endless chain and can move along two rails. Each of the link mechanisms includes first and second rail holders, a plurality of guide rollers provided on the first rail holder and moving along one rail while rotating, and a plurality of guide rollers provided on the second rail holder and moving along the other rail while rotating. The plurality of link mechanisms include three-roller link mechanisms in each of which three guide rollers are provided on the first rail holder and two-roller link mechanisms in each of which two guide rollers are provided on the first rail holder, and the three-roller link mechanisms and the two-roller link mechanisms are arranged alternately.

The present invention provides a method of manufacturing a biaxially stretched film which exhibits small heat shrinkage and has excellent dimensional stability. An unstretched thermoplastic resin film composed of at least one thermoplastic resin layer is biaxially stretched in a longitudinal direction and a width direction to manufacture the biaxially stretched film. The method of manufacturing the biaxially stretched film according to the present invention includes: a process (I) for preheating the thermoplastic resin film to a temperature in a rubbery plateau region in a storage elastic modulus curve; a process (II) for biaxially stretching the thermoplastic resin film under a condition that a stretching speed is 500%/min or higher while heating the thermoplastic resin film to the temperature in the rubbery plateau region; a process (III) for cooling the thermoplastic resin film after the process (II) to a temperature in a glass-to-rubber transition region or a glass region in the storage elastic modulus curve; and a process (IV) for relaxing the thermoplastic resin film after the process (III) under the temperature in the glass-to-rubber transition region.

A gripper for a draping frame having a gripper chassis and at least two opposing mutually movable gripper jaw elements for gripping a film element are disclosed. The gripper jaw elements are provided on a gripper head part of the gripper and the gripper head part of the gripper being movably mounted, at least with one degree of freedom, relative to the gripper chassis.

In one embodiment, a template producing method includes coating a first template having a first pattern with a curable material, and curing the material. The method further includes producing a second template having a second pattern corresponding to the first pattern by peeling the cured material from the first template. The method further includes enlarging the second template, and pasting, on the enlarged second template, a substrate that holds a shape of the second template.