Low-energy cure

Vinyl substituted cyclic hemlamidals 2 and their Interconvertible acetal precursors (eg. acrylamldo-butyraldehyde dimethyl acetal 1) were Incorporated as latent crosslinkers and substrate reactive functional comonomers In solution and emulsion copolymers. Some use and applications data for copolymers prepared with these new monomers are presented. They show low energy cure potential, long shelf life and high catalyzed pot stability In solvent and aqueous media, good substrate reactivity and adhesion, and good product water and solvent resistance. They lack volatile or extractable aldehyde (eg. formaldehyde) components and show enhanced reactivity and hydrolytic stability with amines and diol functional substrates. 

Another megatrend in this competitive business environment is that all production processes need to be world-class and lean. This means that processes must be automated lead times shortened rework, scrap, and waste minimized or eliminated and less product must appear in inventory. This places a burden on the adhesive formulator in that the products not only must perform in service (e.g., creep resistance, peel strength) but also must perform in the assembly process (e.g., fast cure time, minimal scrap, low energy cure). 

Low Energy Curing Pigment Padding and Printing Use of A Highly Active Catalyst System... 

Data from Low Energy Curing Pigment Printing f15)1... 

Parikh, D. V., Low Energy Curing Pigment Printing by Use of a Highly Active Catalyst System, Presented at the Seminar on Special Topics in Textile Printing, at Clemson Univ., Clemson, S. C., April 4-6, 1978. 

Application of Topcoats Appliance Coating Specifications Recent Developments Flow Coat Conversion Electrocoating High Solids Powder Coatings Low Energy Cure Coatings Coatings to Replace Porcelain Future... 

PDMS based siloxane polymers wet and spread easily on most surfaces as their surface tensions are less than the critical surface tensions of most substrates. This thermodynamically driven property ensures that surface irregularities and pores are filled with adhesive, giving an interfacial phase that is continuous and without voids. The gas permeability of the silicone will allow any gases trapped at the interface to be displaced. Thus, maximum van der Waals and London dispersion intermolecular interactions are obtained at the silicone-substrate interface. It must be noted that suitable liquids reaching the adhesive-substrate interface would immediately interfere with these intermolecular interactions and displace the adhesive from the surface. For example, a study that involved curing a one-part alkoxy terminated silicone adhesive against a wafer of alumina, has shown that water will theoretically displace the cured silicone from the surface of the wafer if physisorption was the sole interaction between the surfaces [38]. Moreover, all these low energy bonds would be thermally sensitive and reversible. 

Common designs of industrial low-energy accelerators. (Mehnert, R., Pincus, A., Janorsky, 1., Stowe, R., and Berejka, A., UV EB Curing Technology Equipment, SITA Technology Ltd., p. 138 (1998). With permission from SITA Technology Ltd.)... 

Polymeric films, metallic foils. Curing of adhesives, coatings. Low energy processing in... 

The main advantages of cationic photoinitiators is that they have high reaction rates and require a low energy. They can operate at a low temperature, they are not inhibited by oxygen, they do not promote the polymerization of epoxy groups in the dark, and they are often stable at elevated temperatures. Some disadvantages exist that is, inhibition by bases, chain-transfer reaction by water, and the presence of acids in cured products. 

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