Method for forming multilayer release liners and liners formed thereby

Abstract

Disclosed herein is a multilayer silicone release surface comprising a backing, a support layer on the backing, and a silicone layer of the support layer. The various layers of the multilayer release surface are deposited substantially simultaneously, as for example by a dual die or using curtain coating techniques.

Description

FIELD OF THE INVENTION The present invention generally relates to release surfaces of the type used with pressure-sensitive adhesive (PSA) constructions. More particularly, the present invention relates to multilayer release liners and their methods of manufacture. BACKGROUND OF THE INVENTION A pressure-sensitive adhesive construction, such as a label, generally comprises a facestock or label surface, an adhesive composition adhered to the facestock, and a release liner. The adhesive composition is typically coated on a silicone-containing release surface of the liner. Alternately, the PSA can directly be coated onto the facestock and then be laminated to the release liner. In these combinations, the release liner protects the PSA prior to the label being used and is removed immediately prior to application of the label to another surface. Additionally, the release liner serves to facilitate cost effective manufacture of rolls or sheets of labels. The release liner also functions ...

AI Technical Summary

Benefits of technology

The present invention advantageously provides an efficient method of creating multilayer release liners, thereby overcoming the problems resulting from the prior art processes. The present invention achieves these benefits by providing a method of coating both a support layer and a release layer on a substrate substantially simultaneously. Consequently, separate coating steps are eliminated, and a corresponding savings in both time and costs are achieved.

In summary, the method of the present invention enhances the optimization of the coating process for multilayer release surfaces. The method can be utilized with a wide variety of coatings and substrates in order to produce multilayer release surfaces on open paper surfaces which have release properties equal to or better than those produced on high quality papers.

Problems solved by technology

However, use of these high quality papers increases the cost of the end product adhesive construction, because such papers are typically much more expensive than regular open papers.

Growing concern over the environment has imposed stringent restrictions regarding recovery of the solvent used in applying the solvent based silicone to the high-holdout backing paper or other materials.

When applied to porous low cost papers, such as machine finished (MF) or machine glazed (MG) papers, these materials soak into the paper (penetrate the paper surface) to give ineffective coverage of the paper fibers unless excessively high quantities of expensive silicone are used.

Ineffective coverage of the paper fibers provides unsuitable release liners for PSA applications, especially where high speed convertibility is an essential performance feature.

However, there are several drawbacks to this prior art process.

First, additional costs are incurred because the prior art methods require two coating steps.

Otherwise, there is a potential for undesirable intermixing or destruction of the respective layers.

Second, because two separate coating steps are required, more time is needed for the overall formation of the release liner.

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