PROCESS FOR PRODUCING A DOUBLE-SIDED PRESSURE-SENSITIVE TAPE AND ITS USE
For the production of a double-sided pressure-sensitive adhesive tape, having a closed and open side, possessing a carrier film (e) provided on both sides with a pressure-sensitive adhesive layer (c,c′), the carrier film (e) being a filmlike carrier film not based on rubber, and there bring at least one release film located on the closed side, on the one pressure-sensitive adhesive layer (c), it is envisaged that, from the melt, two identical or different pressure-sensitive adhesives for the pressure-sensitive adhesive layers (c,c′), a film-forming polymer for the carrier film (e), and a film-forming polymer for the release film be formed, that these components be combined to form a composite, and the at the pressure-sensitive adhesives be crosslinded by means of physical and/or radiation-chemical treatment.
1 . A process for producing a double-sided pressure-sensitive adhesive tape with a closed and an open side, comprising a carrier film (e) provided on both sides with a pressure-sensitive adhesive layer, the carrier film (e) being a carrier film not based on rubber, and at least one release film being located on the closed side, on one pressure-sensitive adhesive layer (c), said process comprising forming
two identical or different pressure-sensitive adhesives,
a carrier film-forming polymer, and
a release film-forming polymer,
the melt and combining to form an assembly, and crosslinking the pressure-sensitive adhesives by physical treatment and/or chemical radiation treatment.
2 . The process of claim 1 , wherein at least one primer layer is formed between the carrier film (e) and the pressure-sensitive adhesive.
3 . The process of claim 1 , wherein, to form the at least one release film, a carrier film (release liner) is formed which if desired comprises a release layer on one or both sides.
4 . The process of claim 1 , wherein the producing takes place in a batch process or cascade process.
5 . The process of claim 4 , wherein the producing and coating take place by means of a coextrusion process.
6 . The process of claim 5 , wherein the coextrusion process takes place by the adapter process, with the components being laid layerwise one above another and shaped by means of an extrusion die and/or a multi-manifold die.
7 . The process of claim 6 , wherein the individual components in the form of polymers or in the form of reactive systems as a melt are conveyed separately to a coextrusion system, where simultaneously or successively they are combined, shaped in a die lip to form the film, and subsequently placed.
8 . The process of claim 6 , wherein individual extrusion steps take place separately from one another.
9 . The process of claim 6 , wherein the carrier film, if desired with one or two primer layers above and below, is (co)extruded in one step; the carrier film or one primer layer is coated with the first pressure-sensitive adhesive, which is then laminated with a release film; and lastly a second pressure-sensitive adhesive layer on the open side is extruded onto the assembly.
10 . The process of claim 1 , wherein the producing takes place under pressure on the layer assembly.
11 . The process of claim 1 , wherein the thickness of the carrier film is between 5 and 500 μm.
12 . The process of claim 1 , wherein the thickness of each pressure-sensitive adhesive layer is between 5 and 500 μm, the thickness of the two pressure-sensitive adhesive layers being identical or different.
13 . The process of claim 1 , wherein the thickness of the release film is between 5 and 100 μm.
14 . The process of claim 13 , wherein the coatweight of the release layers (a, a′) is between 1.0 and 4 g/m 2 .
15 . The process of claim 1 , wherein the thickness of the primer layer (d) is between 0.5 and 5 μm.
16 . The process of claim 1 , wherein all film-forming and extrudable polymers function as carrier film.
17 . The process of claim 16 , wherein the carrier film is a polyester.
18 . The process of claim 1 , wherein the pressure-sensitive adhesive layers are formed of polymers and/or copolymers which represent pressure-sensitive adhesives that can be processed from the melt.
19 . The process of claim 1 , wherein the pressure-sensitive adhesive layers are composed of like or different materials.
20 . The process of claim 18 , wherein the pressure-sensitive adhesive layers are formed of pressure-sensitive adhesives based on styrene block copolymers, based on at least one block copolymer of the general type P(A)-P(B)-P(A) (triblock polymers) and P(B)-P(A)-P(B) (inverse triblock polymers), based on at least one block copolymer at least containing the unit P(B)-P(A)-P(B) composed of at least two polymer blocks P(B) and at least one polymer block P(A), or of polyacrylate hotmelt adhesives composed of polymers based on at least 50% by weight of an acrylic ester and/or methacrylic ester with the formula CH 2 ═CH(R 1 )(COOR 2 ), where R 1 is H or CH 3 and R 2 is a linear, branched or cyclic alkyl chain having 1-20 C atoms.
21 . The process of claim 1 , wherein all film-forming and extrudable polymers function as carrier film of the release film.
22 . The process of claim 21 , wherein the carrier film of the release film is a polyester.
23 . The process of claim 21 , characterized in that the release film is composed of a carrier film which is provided with a release layer in the form of a release varnish.
24 . The process of claim 1 , wherein the release layers represent a layer based on silicone or fluorinated polymers.
25 . The process of claim, wherein the release varnish is mutually graduated in its release values.
26 . The process of claim 1 , wherein two-layer release films are used, and if desired have embossings for the purpose of increasing the antistick properties.
27 . The process of claim 1 , wherein the primer layer is formed of PVC/PVAc copolymers, of compounds containing isocyanate or aziridine groups, and of polymers which carry grafted-on functional groups.
28 . (canceled)
29 . (canceled)
30 . (canceled)
31 . (canceled)