Adhesive Pressure

For some applications, such as for repulpable type PSAs, it may be advantageous to incorporate high levels of acrylic acid because this makes the polymer more hydrophilic. At the same time, high levels of acid also improve the water-dispersibility of the adhesive, especially at higher pH where the acid groups are converted to the more water-soluble neutralized salt form. Since the high level of acid increases the of the resulting polymer, a non-tacky material results. To make the adhesive pressure sensitive, the polymer can be softened with water-dispersible or soluble plasticizers, such as polyethers [68]. 

Wherry, R.W., Resin dispersions for water based pressure sensitive adhesives. Pressure Sensitive Tape Council Seminar (May, 1979). 

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... 

Pressure-sensitive adhesives Pressure-sensitive adhesions are actually viscous polymer melts at room temperature. The polymers must be applied at temperatures above their Tg to permit rapid flow. The adhesive is made to flow by application of pressure. When the pressure is removed, the viscosity of the polymer is sufficient to hold and adhere to the surface. Many tapes are of this type where the back is smooth and coated with a nonpolar coating so as not to bond with the sticky surface. The two adhering surfaces can be separated, but only with some difficulty. 

There are many applications for polymeric waterborne adhesives. These include packaging adhesives, pressure-sensitive tape, coatings for textiles, wood adhesives, and various industrial adhesives and coatings. The potential applications for waterborne epoxy adhesives are more limited due to their lack of tack and pressure-sensitive characteristics and the time it takes for the chemical reaction to complete cure. However, waterborne epoxy systems have found significant markets in niche areas. 

Lee (41, 42) offers a valuable contribution on the mechanism of reinforcement and especially on the role of adhesion and wetting in elastomeric adhesives, pressure-sensitive tapes, nonpigmented organic coatings, and composites such as resin-reinforced rubbers or thermoplastics. I am sure it will generate much discussion. Lee (43) presents a... 

Polyterpene resins (600-1500 mol. wt.) (16%), used for adhesives, pressure-sensitive sizes (dry cleaning, paper, chewing gum)... 

In the condenser and evaporator there is a vapour flow, liquid flow, interface position, radial heat transfer with kinetic reaction pressure, liquid pressure, vapour pressure, condensation and evaporation, shear stress, geometry, adhesion pressure, convective heat transport, radial heat transfer under the influence of the gravity field. 

Type of adhesive Adhesives based on different adhesive raw materials with special processing properties (e.g., hot-melt adhesives, pressure-sensitive adhesives), different purposes of use (e.g., wallpaper paste, wood glue), processing temperatures (e.g., cold glue, heat-curing adhesives), availabilities (e.g., adhesive films, solvent-based adhesive). 

Other hot melts are based on low molecular weight polyethylene, combined with tackifying agents. These tend to be lower in cost and performance than the EVA-based hot melts, and they are used primarily with paper packaging, such as cartons and multi-wall bags. Atactic PP can also be used as the base for hot melt adhesives. Pressure-sensitive hot melt adhesives for tapes and labels often employ thermoplastic elastomers, consisting of block copolymers of styrene and butadiene or isoprene. 

The work of Rumpf on bulk powders confirms the relative importance of the van der Waals and electrostatic forces with theoretical strengths for the van der Waals force in the range 2 x 10 to 3 x 10 N/m. These adhesive pressures are relatively constant with change in material whilst electrostatic pressures are highly sensitive to the material, its surface characteristics and... 

Ethyl and butyl derivatives have found uses as adhesives. Pressure-sensitive adhesive tapes made from poly(vinyl ethyl either) incorporating antioxidants are said to have twice the shelf life of similar tapes made from natural rubber. Copolymers of vinyl isobutyl ether with vinyl chloride, vinyl acetate and ethyl acrylate are also produced. 

With anisotropic adhesives, pressure is necessary to squeeze the film so that electrical contacts are made between the aligned electrodes of the parts being bonded. While under pressure and while the electrodes make contact with the metal filler particles, the adhesive cures in the area surrounding the connections and fixes the positions of the z-direction connections. 

DIVERSIFIED ENTERPRISES 101 Mulberry Street, Suite 2N, Claremont NH 03743, (603) 543-0038. Started the Polysurface book store and lists over 2000 titles including several on adhesives, pressure sensitive adhesives, coatings, polymers, plastics, packaging, surface properties, wetting, solubility parameters, and much more. Most books are discounted from their original hst price, some as much as 30%. 

Uses Monomer for acrylics, adhesives (pressure sensitive, structural), coatings (glass, metal, optical, paper, PVC floor, release, textile, wood), electronics, inks, paints, and photopolymers Features Low shrinkage and fast cure... 

Chem. Descrip. Ethoxylated, nonyl phenol methacrylate Uses Monomer for adhesives (pressure-sensitive, laminating) functional intermediate in metal coatings, fiber optics, inks, stereo lithography, and optical illusions reactive diluent for radiation and peroxide cure applies. Features Good pigment/tiller wetting good tackitier compat. 

Uses Urethane-acrylic, flexibilizer providing exc. falling sand and high impact resist, to coatings, adhesives, screen inks, foil coalings, laminaf-ing adhesives, pressure-sensitive adhesives, and metal coalings Features Flexible, nonyel. supplied as base resin or as resin/monomer blends which offer flexibility, clarity, and exc. heat and light stability to UV/EB-cured prods. 

Uses Defoamer for stripping and processing carboxylated SBR and PVC emulsions for adhesives, pressure-sensitive adhesives, food pkg. ad-hesives/paper defoamer in food-contact coatings, paper/paperboard Features Readily dispersible more efficient than high-silica defoamers Regulatory FDA 21 CFR 175.105,176.170,176.180,176.200,176.210 Properties Liq. 100% act. 

Uses Defoamer for aq. systems, adhesives, pressure-sensitive adhesives, paints, high-gloss paints, inks, paper coatings, effluent treatment defoamer in food-contact coatings and paper/paperboard food pkg. 3cih6siv6s... 

Uses Release coating for hot-melt, acrylic adhesive pressure-sensitive tapes and labels of PP, PE, polyester, cellophane, foil, and paper Features Prevents delamination and tearing of the substrate Properties Wh. dry powd. sol. in toluene, heptane, hexane. Shell Cypar m.w. 135,000 m.p. 87-93 C cloud pt. < 25 C (5% in toluene) 99.5% min. assay... 

Chem. Descrip. Urethane diacrylate oligomer Uses Flexibilizer, toughener for coatings, inks, UV/EB adhesives (pressure-sensitive tapes) applied to flexible substrates Features Imparts high flexibility and elasticity, adhesive peel sir., toughness high elong. 120%... 

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