Pressure-sensitive construction

Uses Tackifier for water-based adhesives and sealants based on aciylic, S/B, nat. rubber, neoprene, VAE, and PVAc, pressure-sensitive, construction, contact adhesives, direct food-contact adhesives, coatings Features Solv.-free environmentally friendly Properties Vise. 900 cps soften pt. 92 C pH 9.8 55% solids Pentalyn K [Eastman]... 

Pressure sensitive labels and tapes for the consumer markets form a very significant portion of the PSA industry. Whereas the original products were rather simple in construction and use, today s products often perform unique functions that result from more sophisticated assembly of a label or tape product. Examples of these unique functions include the monitoring of food or drug storage conditions, or the ability to monitor the charge status of a battery. 

In addition to the petrolatum tapes and those based on a laminate of p.e. or p.v.c. with an elastomeric sealant or pressure-sensitive adhesive layer, recent developments have centred around self-adhesive bituminous laminates. These tapes are commonly constructed with a p.v.c. backing, whose thickness ranges from 0 08 to 0 75 mm and a bituminous adhesive compound layer to provide a total tape thickness of up to 2 mm. In order to maintain conformability without compromising impact values, tapes may also be manufactured with a fabric reinforcement within the bituminous layer. 

The other major uses of acrylic latexes are in textile finishing (e.g., stain and wrinkle resistance), adhesives, and floor polishes and waxes. Adhesives are used in many applications, including pressure-sensitive tapes, contact adhesives, and construction adhesives for carpeting and floor tiles. Peelable labels and stamps probably got their start with the Post-it note, invented by Spencer Silver and Art Fry at 3M company many years ago. 

Adhesives. Acrylic emulsion and solution polymers form the basis of a variety of adhesive types. The principal use is in pressure-sensitive adhesives, where a film of a very7 low T (<—20° C) acrylic polymer or copolymer is used on the adherent side of tapes, decals, and labels. Acrylics provide a good balance of tack and bond strength with exceptional color stability and resistance to aging (201,202). Acrylics also find use in numerous types of construction adhesive formulations and as film-to-film laminating adhesives (qv). 

If polymer A has a butadiene rubber block, it will not find application in pressure-sensitive adhesives. It is not readily tackified, it is not readily melt processable, and it will not close a box. However, if dissolved in solvent, compounded with filler and certain resins, it will make the world s best construction mastic, very capable of bonding drywall to wood, etc. If one wants to maximize the solids content in this mastic (use less solvent), and if one wants to design the SBS molecule to be soluble in more environmentally friendly solvents, then in what direction should one head If not A , then where in the region does one strike the balance for a highly extended but tough mastic that allows the solvents of choice while achieving maximum solids and a viscosity low enough to squeeze from a tube ... 

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. 

The sensitivity of the pressure measurement technique used by Pallas and Pethica was 0.2 Nm The precision of the measurements is much poorer, probably because they were made mostly by successive additions, and Pallas and Pethica include in the two-phase regions points that differ by as much as 3 /iNm from the mean pressure. In constructing the isotherms, they have chosen to have the one-phase and two-phase portions meet at an acute angle. This choice leads to coexisting densities markedly different from those reported by Kim and Canned. Which of the interpretations in correct As we shad see, other types of experiments allow us to choose between them. 

The strength values mentioned above depend on the respective construction conditions as well as on the stress duration. An example A plastic hook fixed to a tile by means of a pressure-sensitive adhesive and exposed to stress can come off in the course of time due to a failure of the adhesive layer (creeping). In the case of dynamic stress, the hook can break inside, the bonded joint remains unaffected. In this case, the adherend is the weaker link in the strength chain . 

Combined label/leaflet. Delivered as a thick pressure sensitive label (either reel-fed or block cut), containing a fold-out portion which is the leaflet itself. Applied as one would apply a pressure sensitive label. These have now been around for a number of years. As far as can be ascertained, at least six patents have been taken out in this field. Recently there has been more use of multi-ply construction of these types of label, often using dissimilar materials with rather specialist adhesive systems. Probably the best known are Fix-a-Form from Denny, Peel n Reseal booklet labels, Multipeel, a peel off promotional leaflet or sticker, Dri-peel, Incore and the Double-Dri system. Leaflets use high-opacity (80%+EEL) lightweight (40-70 g/m2) coated or uncoated papers. 

Robond. [Rohm Haas] Waterborne adhesive emulsions for construction, pkg., pressure-sensitive applies. 

Typical pressure sensitive label construction consists of three layers as shown in Figure 3.2. 

The Adhesive The choice of the proper adhesive for one s label is quite obviously of major importance. The two t3rpes of adhesives generally used for pressure sensitive label construction are rubberbase and acrylic emulsion. In addition, most converters of label stock offer a variety of specialty adhesives to meet particularly demanding applications. Some of the terminology associated with pressure sensitive adhesives is as follows. 

The problems that can be caused by highly pressure-sensitive detector cells e.g., RI detector cells) have been solved in different cornnisrcially available detectors by the construction of cells with greater volumes and larger outlet diameters. This is possible because the volume spreading of the peaks in the detection cell is not so critical as in analytical work. 

Silicone adhesives were introduced commercially in 1944 [5, p. 213]. In 1960 the silicone sealants were introduced to the construction industry [11, p. 86]. Silicones are useful at both high and low temperatures and are available today as solvent-based moisture-curing adhesives, one-part moisture-curing adhesives and sealants, two-part curing adhesives and sealants, and pressure-sensitive adhesives. 

Thermoplastic rubber block copolymers, with completely new adhesive performance, were developed in 1965 [21]. The first commercial product was Shell Chemical s Kraton 101, of styrene polybutadiene-styrene composition. This development led to the carboxy-terminated nitrile (CTBN) rubber modifiers used to flexibilize epoxy and other brittle resin adhesives in the late 1960s. Today, the thermoplastic rubber block copolymer adhesives are used in hot melt-, solvent- and water-based adhesives, and as hot melt- and solvent-based sealants. Major applications are as pressure-sensitive adhesives, construction adhesives and sealants, and general assembly adhesives. 

In addition to widespread use as a blend in asphalt/rubber sealants for roofing and other construction applications, reclaim rubber adhesives have been used as an insulation adhesive, as a pipe wrap adhesive, and as an ingredient in some pressure sensitive adhesives. Of interest is the fact that virtually every telephone installation in the United States before 1985 that required a cable splice used a reclaim rubber adhesive. 

At the other end of the spectrum, pressure-sensitive adhesives, contact adhesives, aqueous varnishes, clear sealants and caulks, overprint varnishes for metal decorating and printing are essentially pigment free. Minor amounts of silica are used for gloss reduction in the case of varnishes. Carpet, construction and ceramic/brick adhesives may contain substantial amounts of filler, not only to reduce cost but also to provide shear strength. Gloss and semi-gloss latex enamels... 

Uses Butyl mbber in sealants, coatings, elec, encapsulating compds., and conformal coalings incl. moisture-impermeable coatings, marine and construction sealants, elec, encapsulants, pressure-sensitive adhesives tackifier for pressure-sensitive adhesives processing aid, adhesion promoter... 

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