Microencapsulated adhesives

Microencapsulated adhesive Reactive adhesive mixture, with the (liquid) components encapsulated by a protective skin in the form of finest drops, preventing a reaction during storage. Only after the destruction of the capsule wall, for example, by screwing a nut onto a suchlike coated screw, does a chemical reaction set in and an adhesive layer develop. 

Chao, H. Y. Microencapsulated adhesive prepared by polymerization of encapsulated monomers. GB 2272446, 1994. 

Certain general categories are also listed, such as alloys, aromatic polymer, conductive, delayed-tack, elastomeric adhesives, anaerobic, film and tape adhesives, hot-melt adhesives, inorganic glues, microencapsulated adhesives, rubber-based adhesives, solvent-based systems, thermoplastic resin adhesives, thermosetting-resin adhesives, and water-based adhesives. 

Microencapsulated adhesives Conductive adhesives Electrically conductive adhesives Thermally conductive adhesives... 

Microcapsules are used in a number of pharmaceutical, graphic arts, food, agrochemical, cosmetic, and adhesive products. Other specialty products also exist, thus the concept of microencapsulation has been accepted by a wide range of industries. In order to illustrate how microcapsules are used commercially, it is appropriate to describe a number of commercial microcapsule-based products and the role that microcapsules play in these products. 

PVA in, 25 617 setting speed of, 25 579-580 smectites application, 6 697t solution, 1 532-534 structural, 1 534-545 styrenic block copolymers in, 24 714 use of latex in, 14 711-712 vinyl acetate polymers in, 25 578-583 viscosity of, 25 581 water-borne, 25 475 Adhesive systems, microencapsules in, 16 460... 

A majority of the fasteners used in automobiles in the U.S. are coaled with microcapsitles loaded with an adhesive. Other uses include encapsulated ammonium polyphosphate incorporated in plashes that acts as a hre-rctardant and microencapsulated oil-held chemicals for use hv the oil industry. 

Other significant uses of PCBs included heat exchangers and hydraulic fluids. Prior to controls PCBs were also used in adhesives, coatings, plasticizers and inks for microencapsulating dyes for carbonless duplicating paper as extenders in pesticide formulations and catalyst carriers in olefin polymerizations to impart hydrophobicity to materials and surfaces in bactericide formulations (combined with insecticides), and in immersion oil for microscopes. Mixed with chloronaphthalenes, PCBs were also used in wire and cable insulation in the mine and shipbuilding industries (ref. 80, p. 455). 

A significant amount of development is currently occurring relative to latent catalysts because of interest in their long shelf life, high reactivity, and single-component adhesive formulations. Present technologies involve absorption of acidic or basic catalysts in molecular sieves, formation of Lewis acid salts or other amine salts, microencapsulation of amines, and other novel segregation methods. 

Amines have also been microencapsulated within small cellulosic or polyelectrolyte capsules. This is a method for keeping the amine separate from the epoxy resin during storage. When the user decides to initiate cure, the capsules are broken, usually in the application process, and the amine is free to react with the epoxy resin. A successful example of this type of product is an epoxy adhesive that can be preapplied to machine screw threads. When the screw is ultimately threaded into place, the shearing action causes the capsule to break. Bond strengths are generally low for this type of adhesive, but this may not be important in certain applications. 

The formation of inclusion complexes of lipids inside the amylose helix is not the only important factor regulating the functional properties of foodstuffs. The adsorption of lipids on starch surfaces can prevent the separation of components in frozen starch noodles. Such surface sorption reduces the viscosity and adhesiveness of the starch.888 The latter property can also be important in the microencapsulation of medicines. For example, a complex of cornstarch with glucolipids has been patented as an excipient for 3-(p-chlorobenzyl)-6-methoxy-2-methylindole-l-acetic acid.889... 

One problem in using these techniques is getting sufficient quantity of pesticide adhered to the seed or fertilizer granule. Solutions to this problem include using a powdered clay or silica to help absorb liquid pesticides, using microencapsulated liquid pesticides, and using a polymer coating to increase adhesion of pesticide particles. 

Poly(carbodiimides) are sometimes used as adhesive primers. Film forming carbodiimide homo- or copolymers have been used in microencapsulation techniques for pressure sensitive copy paper. Oligomeric acylureas are obtained from polyunsaturated carboxylic acids and carbodiimides as monomers for coatings. ... 

Use Photographic film sizing textile and paper adhesives cements capsules formedicinals matches light filters clarifying agent desserts, jellies, etc. culture medium for bacteria blood plasma volume expander microencapsulation printing inks nutrient protective colloid in ice cream. 

Blocked reactive adhesives Adhesives in which the inter-reaction of the components is eliminated by mechanical (e.g., separated packing units, microencapsulation) or chemical measures (special formulations of resins, respectively, hardeners). 

Brochu, A. B. W. Chyan, W. J. Reichert, W. M. Microencapsulation of 2-octylcyanoacrylate tissue adhesive for self-healing acrylic bone cement. Journal of Biomedical Materials Research, Part B Applied Biomaterials (2012), 100B(7), 1764-1772. 

Chemical companies are interested in the development of innovative system solutions, that is, new functional materials in which known molecules are integrated to show new effects. Flavor and fragrance companies are interested to protect and precisely release their valued molecules (the payload ). The polymer industry demands encapsulated curing agents and encapsulated reactants. These are just three examples, out of many, that show that microencapsulation is mainly used for the purpose of protection and controlled release. Since at least a decade, therefore, traditional low-volume markets for microcapsule-based products are expanding to include fine chemicals, adhesives, inks, fragrances, toners, sealants, and detergent manufacturers. ... 

Pea proteins show good properties for their potential application, in particular for the production of adhesives, bio plastics, emulsifiers, and wall forming materials for microencapsulation. ... 

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