Pressure Sensitive Adhesives PSAs

In contrast to UV-laminated adhesives, radiation is appUed directly to the photosensitive resin, without having to penetrate through another material, very much 

In the production of tape adhesives, step 3 can be skipped by using a polymer film that has been release treated on one side as a substrate. 

The photosensitive resin consists either of a liquid functionalised oligomer, usually with acrylate groups, or a reactive polymer which will be applied as hot melt. There are two main classes of reactive polymers acrylic hot melts which may contain a tackifying monomer, and thermoplastic rubbers which predominantly block copolymers with polybutadiene or polyisoprene chains [3]. A radical-type photoinitiator is always needed to produce, upon UV-exposure, the free radicals that will initiate the polymerisation or cross-linking process. 

The reasons for using UV-curable PSAs, rather than solvent-based adhesives, remain essentially the same as for the other UV-curable systems and include high cure speed, reduced VOC emission, low energy consumption and enhanced product performance. The subject has been extensively investigated in recent 

Here are a few examples of different types of UV-cured PSAs developed in various applications  

The main property that distinguishes a pressure-sensitive adhesive from other types of adhesives is that it exhibits a permanent and controlled tack. This tackiness is what causes the adhesive to adhere instantly when it is pressed against a substrate. After it adheres, the PSA should exhibit tack, peel, and shear properties, which are reproducible within 

Because of the precise control of the degree of cross-linking attainable by the electron beam process, it is well suited for the production of PSAs. Recent developments in EB design, particularly lower voltage, and materials developments have made electron beam curing of pressure-sensitive adhesives affordable, practical, and possible.  

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Release coatings are important components of pressure sensitive adhesive (PSA) products such as tapes and labels [1]. Release materials are coated onto the backside of PSA tape backings (often called low adhesion backsizes or LABs in this form) to provide the desired tape roll unwind force. They are also coated onto various substrates to form release liners for PSA products such as labels and transfer tapes. Typically the thickness of the release coating is less than 1 p,m, and often times less than 0.1 jLm. Release coatings can be thought of as the PSA delivery system, providing a controlled unwind or release force and protecting the adhesive from contamination and unintentional contact until it is applied. 

Pressure-sensitive adhesives (PSAs) based on acrylic, natural rubber and silicone are employed primarily for ease of application. To name Just a few applications, PSAs bond decals to surfaces, interior decorative surfaces to interior panels, interior trim pieces in place directly or hook and loop tape for the same purpose, structural shims in place during manufacturing and acoustic (sound deadening) materials to body skin interior surfaces. Tape products with pressure-sensitive adhesive on one or both surfaces are used for such functions as cargo compartment sealing, as a fluid barrier to prevent spills and leaks in the lavatories and... 

A product is only considered to be totally biodegradable if all its single components can be degraded naturally. Currently, pressure sensitive adhesives (PSA) are mostly based on non-biodegradable synthetic polymers such as polyacrylates, ethylene-vinyl acetate copolymers and styrene block copolymers [124]. Therefore there is a growing demand for the application of biodegradable PSAs on naturally degradable products like paper and cardboard. 

See also ATP entries hydrolysis of, 16 553 20 641 production of, 13 288 Adenosylcobalamin, 25 804 Adenoviruses, 3 136 Adequate Intake (AI), 25 784, 785t Adern, E., 11 8 Adherends, 1 501, 524 Adhesion, 1 501-524. See also Adhesive entries Pressure-sensitive adhesives (PSAs)... 

Adhesives, 1 501-502, 524-553. See also Adhesion Pressure-sensitive adhesives (PSAs) acrylic ester polymers, 1 390 alkanolamines from olefin oxides and ammonia, 2 135... 

UV curable pressure-sensitive adhesives (PSAs) are based on two types of UV curable maferials ... 

In the past, electron beam radiation was applied to produce PSA exclusively however, recent improvements in UV curing technology (precise UV dose control, suitable photoinitiators) permit UV to be used to produce pressure-sensitive adhesives. PSA formulations can vary in consistency from low-viscosity liquids up to solids melting at 80°C (176°F). Therefore, applications may vary from screen printing to roll coating to melt extrusion. Coat weights for most PSA materials vary from 1 to 10 g/m. ... 

Energy consumption and EPA standards are becoming important considerations to pressure sensitive adhesive (PSA) converters. 

The influence of parameters such as crosslinking agent aluminium acetylacetonate content, introduction time of monomers, amount of reactor charge, distribution of N-vinyl caprolactam (VC), diverse crosslinkers, viscosity and molar mass of the synthesised pressure-sensitive adhesives (PSA) and solvent balance and transfer agent kind and content on such important parameters of PS A as shrinkage, plasticity, adhesion to steel and deformation are examined. Synthesised pressure-sensitive adhesives based on acrylic polymers and containing 2-ethylhexyl acrylate (2-EHA), methyl acrylate (MA), acrylic acid (AA) and VC are used for production of self-adhesives containing PVC carrier. 4 refs. 

Organosilicone Coating Products. SiHcone products are used in a large variety of coatings appHcations most prominent among these are siHcone pressure-sensitive adhesives (PSA), plastic hardcoats, and paper release coatings (398,399). 

In terms of the system design of TDS, there are three types of system constructions reservoir type, matrix type, and drug-in-adhesive type. In reservoir type and matrix type, pressure-sensitive adhesive (PSA) is only expected to keep the system on the skin. Hence, the necessary conditions for adhesives are almost the same as those of bandages, namely, well skin adhesiveness and low skin toxicity whereas in drug-in-adhesive type, the drug is incorporated into the adhesive so that the interaction between drugs and the PSA is more critical, as discussed later. 

Some solvent cements and solvent-containing adhesives, such as pressure-sensitive adhesives (PSAs), will collapse thermoplastic foams by dissolving the cell walls. In such cases water-based adhesives based on SBR or polyvinyl acetate, or 100%-solids adhesives are often used (1). 

Silicone release coated papers and films, when laminated to pressure-sensitive adhesive (PSA) coated materials, such as adhesive coated labels and tapes, provide both protection for the adhesive coated product (such as in preparation for slitting, die-cutting, and the like) and they provide subsequent easy release of the release coated paper or film from the adhesive surface immediately prior to its intended final use... 

Pressure-sensitive adhesives are the essential components of adhesive tapes and labels. They are polymers with permanent tack, usually applied on substrates (plastic/metal films, siliconized papers). To enhance their tack, compounds with high inherent tack are added, for example, resins, plasticizers. Pressure-sensitive adhesives reach their adhesion on the material to be bonded by contact pressure, from which the term pressure-sensitive adhesive (PSA) derives. Apart from electron radiation, also UV-radiation curing described in Section 4.3.2 is applied in adhesive tape manufacturing. The monomer molecules to be polymerized are applied, in liquid form, to the substrates to be coated by rolling and are continuously cured to a polymer layer within seconds under a UV-radiation source. Depending on their composition, predetermined adhesion values can be adjusted. The adhesive tapes can be subsumed under the systems shown in Figure 5.4 ... 

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