See WO 01/78966. Coextrusion of sheet- or ribbonformed flows in which one or two components are extruded onto or into a third component in pulses through a flap closure. In one aspect this is done to cover a material of high viscosity with a material of very much lower viscosity on one or both surfaces. Then the pulses are very short and made under a high pressure. This is the only way to make even coextrusion of materials which are especially different in their flow behaviors.
In another aspect the invention is used to make a pipe of stiff segments alternating with soft segments.
In a third aspect the invention is used to coextrude powder formed material with a liquid (molten) material.
See WO 01/96102 A1. A crosslaminate construction which is particularly suited for form-fill- and-seal and open mouth bags. Optimized shock-peel-strength of the heatseals in the bags and minimized tendency to creep in the lower layers of filled bags in a stack.
See WO 02/51617. An improved construction of an annular coextrusion die, especially advantageous when a big diametre is wanted and when there are coextruded surface layers of melt viscosity lower than that of the main component.
See WO 03/033238 A1. Principles of making the thickness of the individual coextruded layers more even than it can be done with todays annular coextrusion dies, considering that the die must be adaptable to different rheologies in the coextruded materials.
Controlled Melt Orientation
See WO 03/033241 A1. Devices in connection with annular coextrusion dies, having the funktion to increase and control the melt orientation, mainly in the logitudinal direction. Expected very important for the future developments of crosslaminates.
Cross Lines (Not yet published)
On one surface of the turbular film used in the crosslamination process there are coextruded strands, either coloured to give special sales appeal, or of a material which can promote the tear resistance. The spacing between the strands is a few cm and the strands are very thin. They are on the surface which after spiral cutting and lamination is inside the laminate. In this laminate the two arrays of strands form a criss-crossing pattern. The grooved roller strectching which always is used in our XF manufacturing process, will produce at least a slight texturing of the laminate, and this in combination with the differently pigmented strands makes an interesting 3-dimensional effect.
When the invention is used to promote tear resistance, there is coextruded a continuous thin "lamination Layer" between the strands and the main layer ( the "strength layer"). The strands are choosen to give spotwelding where they intersect, and the lamination layer is choosen to make weak bonding over the rest of the laminate. Strong bonding all over would make the tear propagation strength poor, especially when the laminate weigth is lower that about 100gr. Per sq.m. Low bonding all over would be nuissance. The Cross Line invention makes a good combination of strong bonding and weak bonding.
See WO 02/102592 A1. This invention is briefly explained in the "Background" section and in "History"/"3rd generation".
The following should be added:
The channels or pockets formed by the flutes can be utilized for special purposes. Thus they can be filled with a protective agent e.g. an antirust agent, an oxygen scavenger, or a fire retardent. If there are made staggered.rows of perforations on the two sides of the laminate, this can be used as a filter material, or as material which lets air through but stops water, similar to but for several uses better than microperforated film material.
(Not yet published). This is closely related to "miniflutes", covering some aspect which were not covered in "Miniflutes".