Лако-красочные материалы — производство

5.1.1

Introduction

Pressure-sensitive adhesives (PSAs) are permanently tacky at room temperature, and firmly adhere to a variety of surfaces upon contact with finger or hand pressure. They do not require any activation by either water, solvent or heat to build up a strong bond with such materials as paper, plastics, glass, wood or metals. Additionally, some of these products have a sufficiently cohesive strength so that they can be removed cleanly from smooth surfaces, without leaving a residue. In contrast to systems activated by heat, radiation or moisture, adhesion is obtained without changing the chemical or physical condition of the PSAs. They must present an adequate deformability to adapt to rough surfaces, a sufficient wetting capacity towards the adherent surfaces to provide for proper adhesion, and a sufficient inner strength to withstand repeated loads over a prolonged period of time [1].

At present, PSAs are used in a variety of applications, most often in the form of coated products available as adhesive tapes (in roll form), leaves or sheets, or as die cuts. They help to solve various problems in many branches of industry and in a most varied array of everyday applications, be it at home, at the office, or for hobby activities. The following commercialized products are available:

• single-sided adhesive tapes (e. g. for fastening, covering, protecting or packaging)

• double-sided adhesive tapes (for joining, fastening, mounting, splicing)

• self-adhesive labels

• repositionable sheets of notepaper (Post-it®)

• self-adhesive special products (e. g. removable fastening systems, self-adhesive damping products, electrically/thermally conductive adhesive tapes)

Development activities are focused on the creation of a third functionality besides peel and shear strengths, for example to confer thermal, electrical or optical conductivity to PSAs. Another priority is the development of high-performance adhesive systems that not only adhere to glass, metal, ceramics or high-grade plastic materials, but also to low-energy, mostly structured modern polymer materials.

5.1.2