COVER FOIL

Abstract: A light-transmitting cover foil consists of a laminate, comprising: a first layer which is for instance only plastically deformable at a relatively high first temperature and is provided in advance with a structure, for instance a texture; a second layer adhered thereto consisting of a dimensionally stable carrier layer, and adhered thereto; either a third layer thermally-activated at a relatively low second temperature, or a pressure-sensitive glue layer, wherein the outer surface of the first layer is of the type which substantially does not adhere to the outer surface of the third layer such that in the rolled-up state of the cover foil these outer surfaces lying on one another substantially do not mutually adhere.

Description: Cover foil The invention relates to a light-transmi ting cover foil intended to be applied adheringly to a surface optionally carrying information such as letters, numbers, images or the like, for instance the surface of a carrier plate, which foil consists of a laminate, comprising: a first layer which is for instance only plastically deformable at a relatively high first temperature for instance in the range of 120°C - 200°C, for instance comprising polycarbonate, PMMA, PVC, ABS, PP, PE, which first layer is provided before, during or after joining together with the other layers with a structure, for instance a texture and/or a pattern pressed out of its main surface by exerting pressure and increasing temperature to at least the said first temperature, for instance by using a heated profile roller; a second layer adhered thereto consisting of a dimensionally stable carrier layer, for instance comprising polycarbonate, PMMA, PVC, polyester/PET, ABS; and adhered thereto, either a third layer meltable and thus thermally-activated at a relatively low second temperature, for instance in the range of 50°C - 90°C, and consisting of a hot-melt or glue layer, for instance comprising EVA, EEA, EBA, EMA, GBA or other low-melting plastics, including polyolefins, copolymer esters, polyacetate esters, softened PVCs, acrylates and acryl- based substances; or a pressure-sensitive glue layer, which said layers are mutually connected by adhesive agents, for instance by making use of co- extrusion. Such a cover foil is described in applicant- 1 s non pre-published international patent application PCT/NL95/ 00318. During use of a cover foil according to the said older patent application it has been found that, after winding of the foil into a roll, the outer surfaces of the foil then pressing onto each other with some force cannot always be entirely prevented from mutually adher¬ ing. The third layer can be of the thermally- activated type, which for instance only melts at about 80°. Under ideal and substantially tension-free and friction-free winding conditions the outer surfaces of the first and third layer can then in principle not adhere to each other. It has nevertheless been found that also at the said melting point this adhesion does in fact occur. It occurs because a thermally-activated glue also has a certain, albeit slight, pressure-sensitivity, but also because during winding up of the foil at a certain strip tension the layers lying on top of one another can slide over each other with friction, whereby a quite considerable temperature increase to above the said melting point can occur locally. It will be apparent that when layers mutually adhere an easy, well-controlled and disturbance-free unwinding cannot always be guaranteed. The invention has for its object to embody a cover foil of the said type such that the described drawbacks do not occur. In this respect the cover foil according to the invention has the special feature that the outer surface of the first layer is of the type which substantially does not adhere to the outer surface of the third layer such that in the rolled-up state of the cover foil these outer surfaces lying on one another substantially do not mutually adhere. The foil can for instance be characterized by a light-transmitting non-adhesive layer arranged on the outer surface of the first layer. This variant can be particularly embodied such that the non-adhesive layer consists of a film or layer of silicone material, PTFE, PE, PP and the like or combinations thereof. Yet another embodiment has the special feature that the first layer consists of a light-transmitting material which substantially does not adhere to the outer surface of the third layer. This latter embodiment can have the feature that the first layer consists of light-transmitting, for instance transparent, PTFE, PE, PP and the like or combinations thereof. It is noted that the stated, undesired mutual adhesion of the two outer surfaces of the foil could also be prevented by arranging a protective foil against the outer surface of the third layer. The drawback thereof is that this protective foil must be removed during unwinding and separately rolled up or discarded. This makes machine processing of the foil needlessly complicated and also has the drawback of resulting in additional waste. Attention is drawn to the fact that when a pressure-sensitive third layer is used the melting temperature of the first layer can be relatively low, in particular considerably lower than the range of 120°- 200°C mentioned in the preamble. A silicone film can be arranged by making use of a solvent evaporating after application such as toluene, by spraying on an emulsion or by applying a pure silicone material without using a solvent. Use can for instance be made of a squeegee or the like. The thickness of a silicone film can be very small and lie for instance in the order of a few micrometers. When a relatively porous outer surface is used it can be recommended to treat this surface such that it is sealed, for instance by a treatment at increased temperature and a certain pressure. The invention will now be elucidated with reference to the annexed drawing. Herein: figure 1 shows a schematic view of a device which is adapted for processing a cover foil, wherein the outer surface of the third layer is covered by a protective foil which must be removed before use; figure 2 shows a cross section through a first embodiment of a cover foil according to the invention; figure 3 is a cross section through a variant. Figure 1 shows a device 1 for arranging a light-transmitting cover foil 3 on a carrier 2. The cover foil 3 comprises a third layer acting as glue layer. The glue is of the pressure-sensitive type and is covered in the rolled-up state on roll 4 by a silicone protective foil 5 which must be removed prior to the application process in application station 6. For this purpose the protective foil is deflected by a deflecting roller 7 and guided therefrom to a waste roll 8 in order to be wound thereon. In order to arrange onto the carrier 2 the foil 3 from which the protective foil 5 is removed, this foil 3 is deflected by deflecting roller 9 and subsequently introduced into the pinch between two rollers 10, 11 for pressing onto carrier 2 while being transported according to arrow 12. It will be apparent that this device 1 operates impractically insofar that special provisions are necessary to remove the protective foil 5. Figure 2 shows a light-transmitting cover foil according to the invention. This foil comprises a first layer which is only plastically deformable at a relatively high first temperature, for instance in the range of 120°C - 200°C, for instance consisting of polycarbonate, PMMA, PVC, ABS, PP, PE or combinations thereof, which first layer 13 is provided before, during or after joining together with the other layers mentioned hereinbelow with a structure, for instance a texture on the outer surface 14. Adhered to the first layer 13 by means of adhesive agents is a second layer 15, consisting of a di ensionally stable carrier layer, for instance consisting of polycarbonate, PMMA, PVC, polyester/PET, ABS or combinations thereof. On the underside of this second layer is a glue layer 16 which is either meltable at a relatively low second temperature, for instance in the range 50° - 90°C, or which is pressure-sensitive. This layer 16 is adhered to the second layer 15 by means of suitable adhesive agents. In order to ensure in the case of a rolled-up foil 17 that the glue layer 16 cannot adhere to the free upper surface of the first layer 13, that upper surface of first layer 13 is provided in this embodiment with a non-adhesive layer 18. In this embodiment the non- adhesive layer consists of a film of silicone material. Figure 3 shows a variant wherein the whole first layer 18 of cover foil 19 consists of a material which does not adhere to the glue layer 16. This material can for instance be transparent PTFE. Attention is drawn to the fact that with use of the invention the non-adhesive layer is situated on the outer surf ce of an applied cover foil . Graffiti for instance will therefore not adhere to this foil, which can be regarded as a very welcome additional feature of the invention. Attention is further drawn to the fact that the gloss of an applied foil can also be controlled by the choice of the non-adhesive layer. *****

Claims: Claims l. Light-transmitting cover foil intended to be applied adheringly to a surface optionally carrying information such as letters, numbers, images or the like, for instance the surface of a carrier plate, which foil consists of a laminate, comprising: a first layer which is for instance only plastically deformable at a relatively high first temperature for instance in the range of 120°C - 200°C, for instance comprising polycarbonate, PMMA, PVC, ABS, PP, PE, which first layer is provided before, during or after joining together with the other layers with a structure, for instance a texture and/or a pattern pressed out of its main surface by exerting pressure and increasing temperature to at least the said first temperature, for instance by using a heated profile roller; a second layer adhered thereto consisting of a dimensionally stable carrier layer, for instance comprising polycarbonate, PMMA, PVC, polyester/PET, ABS; and adhered thereto, either a third layer meltable and thus thermally-activated at a relatively low second temperature, for instance in the range of 50°C - 90°C, and consisting of a hot-melt or glue layer, for instance comprising EVA, EEA, EBA, EMA, GBA or other low-melting plastics, including polyolefins, copolymer esters, polyacetate esters, softened PVCs, acrylates and acryl- based substances; or a pressure-sensitive glue layer, which said layers are mutually connected by adhesive agents, for instance by making use of co- extrusion, characterized in that the outer surface of the first layer is of the type which substantially does not adhere to the outer surface of the third layer such that in the rolled-up state of the cover foil these outer surfaces lying on one another substantially do not mutually adhere. 2. Cover foil as claimed in claim 1, characterized by a light-transmitting non-adhesive layer arranged on the outer surface of the first layer. 3. Cover foil as claimed in claim 2, characterized in that the non-adhesive layer consists of a film or layer of silicone material, PTFE, PE, PP and the like or combinations thereof. 4. Cover foil as claimed in claim l, characterized in that the first layer consists of a light-transmitting material which substantially does not adhere to the outer surface of the third layer. 5. Cover foil as claimed in claim 4, characterized in that the first layer consists of light- transmitting, for instance transparent, PTFE, PE, PP and the like or combinations thereof. *****

Inventors: REINDERS JOHANNES ANTONIUS MAR, REINDERS, JOHANNES, ANTONIUS, MARIA
Applicants: REINDERS JOHANNES ANTONIUS MAR, SALLMETALL BV, REINDERS, JOHANNES, ANTONIUS, MARIA, SALLMETALL B.V.
Application year: 1997
Main classification: B32B27
IPC codes: B32B27, C09J7