Adhesive polymers radiation-curable

V. D. McGinness, "Polymer and Formulation Design Characteristics for Developing Adhesive Bonding Radiation-Curable Systems," in Ref. 14. 

While the chemistry of radiation curable hot melt adhesives is the same as that used in liquid (syrup) adhesives and coatings discussed elsewhere in this volume, there is a fundamental difference between the objectives of reaction in the two types of systems. Syrups consist largely or entirely of reactive monomeric and/or oligomeric materials. Radiation is used to initiate the polymerization of virtually the entire mass. In contrast, hot melts generally contain polymers initially, and these polymers are capable of reaction via radiation to produce chain extension and... 

Uses Monomer improving adhesion in thermoset acrylic and urethane coatings, fibers, syn. resins, radiation-curable inks ManufJDistrib. Monomer-Polymer Dajac Labs Rhodia... 

The papers presented in the following chapters represent advances in pressure sensitive adhesives (ultraviolet light activated acrylate monomer - low Tg polyether formulations) photoinitiated cationic polymerization (light activated aryliodonium and arylsulfonium salts of lewis acids in epoxy resin formulations) polymer and formulation design criteria for radiation curable adhesives radiation curable composites (dynamic thermal analysis characterization of electron beam cured... 

More commonly, acrylic polymers have been utilized as the sole or major components of radiation-curable adhesive systems. These acrylics have included a homopolymer and many examples of copolymers. One UV-cured acrylic ester copolymer system cited was claimed to have 180° peel strength of 4.8 to 5.5 pounds/inch. Radiation-curable systems based on copolymers of vinyl acetate and 2-ethylhexyl acrylate have been reported more frequently than other compositions and sometimes have been applied by hot melt techniques. These pressure-sensitive adhesives have displayed 180° peel strengths ranging from about 1.5 to 3 pounds/inch when cured by either UV or EB radiation. Not surprisingly, solutions of acrylic polymers in acrylic and vinyl monomers have also been used as radiation-curable pressure-sensitive adhesives. 

Polymer and Formulation Design Characteristics for Developing Bonding Capabilities of Radiation-Curable Coatings and Adhesive Systems... 

Each of the above concepts, as well as other factors such as energy requirements for cure and post-cure effects, are major contributors toward developing radiation curable coating systems that have bonding capabilities to a wide variety of substrate materials. The major emphasis of this paper will center on polymer design for improved adhesion. 

POLYMER DESIGN IN RADIATION CURABLE COATINGS FOR IMPROVED ADHESION... 

Fig. 1. Adhesive Bonding Capabilities of Radiation Curable Coating Systems Containing Polymer Additives as a Function of Effective Chain Length and Specific Placement of Unsaturation Sites...

In Table 1, a wide variety of polymer systems were examined for their ability to promote adhesive bonding of a radiation curable coating formulation to a metal substrate. In all cases the high Tg values (greater than room... 

Newer adhesives of the acrylic, anaerobic or radiation-curable types must, if they are structural, have a relatively high degree of toughness and durability if they are to compete with or challenge epoxy adhesive systems. Likewise, newer radiation-curable, pressure-sensitive adhesive systems must exhibit the properties of permanence largely associated with cross-linked adhesive masses deposited from an acrylic solution polymer base. Epoxy resin structural adhesives largely define the existing area on the one hand the cross-linked acrylics deposited on plastic or metallic films the other. 

The use of elastomeric or flexibilizing modifiers occurred and grew with epoxy resins first. Various aspects of toughened epoxy adhesives have been covered in reviews by the present authors (2,3), where the elastomeric modifiers have essentially been carboxylic, liquid and solid butadiene/acrylonitrile polymers. There has not been a systematic review, however, of these and other reactive liquid polybutadiene/acrylonitriles in the burgeoning areas of acrylic, anaerobic and radiation-curable systems. Thus, this paper s intent. 

K. C. Stueben is a Senior Research Scientist at Union Carbide s Technical Center in Bound Brook, New Jersey. He received his Ph.D. from the Polytechnic Institute of New York in 1960. His research experience has encompassed a number of areas, including micellar catalysis, synthetic paper, polymer flammability, exploratory adhesives, radiation curable pressure sensitive adhesives and both laboratory and plant scale preparation of condensation polymers, latexes and industrial chemicals. He is the author of numerous papers, chapters and patents in these fields. Dr. Stueben is currently Director of the Adhesion Society s course on Adhesion. 

GPC is also a very useful technique for characterizing the molecular mass range/distribution of the various organic polymers and co-polymers used as thickeners in anaerobic, acrylic, and radiation-curable adhesives. The base polymer, tackifying resin, and petroleum wax components of hot-melt type adhesives may also be characterized in a similar manner. 

Frances, R.S. and Edelman, R., Ultraviolet radiation-curable acrylic polymer pressure sensitive adhesives, Japanese Patent JP 200004-4887, 2000 Frances, J.M., Delchet, L., Amaut, C., Gambut, L., Pressure-sensitive adhesive silicone compositions. World Patent 0310257, CA-2003-97495 2003. 

Woods, J., UV-curable adhesives, in Radiation Curing of Polymers, Randell D.R. (Ed.) (pp. 102-115), Royal Society of Chemistry, London, Special Pubhcation No. 64,1987. 

Those formed by addition polymerization without by-product formation. Among this group are several of the most interesting of the new adhesives, including polyesters, epoxies, urethanes, cyanoacrylates, anaerobics, and radiation-curable polymers. Conventional acrylics and vulcanizing rubbers are also in this category. 

Pressure-sensitive adhesives based on acrylic polymers grew 3.5-fold in the last dozen years. The acrylics are mostly emulsions and solutions, plus small quantities of radiation-curable systems. In tapes, acrylic adhesives are applied mainly to non-paper substrates such as polypropylene, acetate, cellophane, and polyester. In labels, acrylics are used for making permanent paper labels and plastic labels. 

Ellerstein SM, Lee SA, Palit TK. Radiation-curable adhesives. In Fouassier JP, Rabek JF, eds. Radiation Curing in Polymer Science and Technology. Vol. IV. Andover Chapman and HaU 1993 73-86. 

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