Flexible heated area element

Abstract

The planar element comprises a first self-adhesive side face, a second self-adhesive side face, a layer sequence comprising a heating layer, a contacting layer and an adhesive layer. The heating layer is contacted and is electrically conductively connected with the first side face of the contacting layer. The adhesive layer is contacted with the second side face of the contacting layer, where the heating layer consists of an intrinsically heatable first self-adhesive mass (10) that is formed as a self-heatable posistor when an electric current is passed through. The planar element comprises a first self-adhesive side face, a second self-adhesive side face, a layer sequence comprising a heating layer, a contacting layer and an adhesive layer. The heating layer is contacted and is electric conductively connected with the first side face of the contacting layer. The adhesive layer is contacted with the second side face of the contacting layer, where the heating layer consists of an intrinsically heatable first self-adhesive mass (10) that is formed as a self-heatable posistor when an electric current is passed through. The adhesive layer consists of a second self-adhesive (30) and the contacting layer is a two-dimensionally extending perforated contacting element (20). The perforated contacting element consists of notches whose principal extent runs in a spatial direction. The perforated contacting element has a branched comb structure or finger structure. All of the sub-regions of the perforated contacting element are in electrically conducting connection with one another through the perforated contacting element. The perforated contacting element has two sub-regions which are not in electrically conducting connection with one another via the perforated contacting element. The first self-adhesive comprises electrically conductive filler, which is conductive carbon black. The first self-adhesive mass consists of partially crystalline polymers. The first self-adhesive and / or the second self-adhesive is / are a pressure-sensitive adhesive based on acrylates and / or methacrylates, natural rubbers, synthetic rubbers and / or silicones. The first self-adhesive and / or the second self-adhesive is a hotmelt adhesive based on polyolefins and copolymers of polyolefins and their acid-modified derivatives, ionomers, polyamides and their copolymers and block copolymers such as styrene block copolymers. The composition of the first self-adhesive is identical to or different from the composition of the second self-adhesive. The planar element has a third self-adhesive on the side face of the heating layer that faces away from the perforated contacting element. The heating layer has a thickness of 20-200 mu m. The planar element comprises a flexible permanent backing. The planar element is backing-free form. Independent claims are included for (1) an adhesively bonded assembly; and (2) a method of producing a planar element.

Description

technical field [0001] The invention relates to a planar element with a first self-adhesive side and a second self-adhesive side, which is characterized by a layer sequence comprising a heating layer, a contact layer and an adhesive layer, wherein the The heating layer is in contact with the first side of the contact layer and is in conductive communication with it, and wherein the adhesive layer is in contact with the second side of the contact layer, and wherein the heating layer is designed to have a positive temperature An inherently heatable first self-adhesive of a positive temperature coefficient thermistor that generates heat when current is passed through it, and wherein the adhesive layer is formed of a second self-adhesive. The invention also relates to an adhesively bonded assembly comprising a bonded substrate and a planar element of this type; a method for producing said planar element; and the use of the planar element for bonding substrates in the automotive in...

AI Technical Summary

Problems solved by technology

[0013] However, in general, the toughness of this type of composite tape is low at best

The heating elements known from the prior art which can be bonded in the form of composite tapes therefore have the disadvantage that they are relatively rigid

Furthermore, the rigidity of the structure of conventional bondable heating elements can compromise the mechanical low-temperature impact strength of bonds between dissimilar bonded substrates such as mirrors and mirror supports

[0014] In particular, in the case of large curved substrate surfaces, the problem arises that as manufacturing tolerances (such as those of the mirror glass and support plate) produce different gap sizes on the surface, it often prevents full-area adhesion bond

However, as a disadvantage of this construction, it has been found that the adhesive becomes increasingly Loss of pressure sensitive adhesion in multiple places

Furthermore, in this case, it is sometimes fundamentally difficult to develop sufficiently significant PTC thermistor properties using generally amorphous pressure-sensitive adhesive polymers

[0018] Furthermore, for this structure, too, there remains the problem of insufficient toughness of the planar elements, thus significantly reducing the reliability of the adhesive bond, which in turn leads to a reduction in the mechanical, electrical and thermal contact achieved through this bond, thereby reducing the Maximum amount of heat available, making heat transfer more difficult

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