Adhesive fast curing

Chem. Descrip. Carboxyiated styrene-butadiene latex Uses Binder for nonwovens, textiles, froth coatings of upholstery fabrics Features Soft self-crosslinking exc. water and solv. resist., tensile str. good adhesion fast cure rate... 

Features Low vise. good adhesion fast cure response good surf, and through cure optimum absoq). 200-300 nm Properties Clear to It. yel. liq. sol. in org. soivs., monomers, oligomers ... 

Polyurethane adhesives are known for excellent adhesion, flexibihty, toughness, high cohesive strength, and fast cure rates. Polyurethane adhesives rely on the curing of multifunctional isocyanate-terrninated prepolymers with moisture or on the reaction with the substrate, eg, wood and ceUulosic fibers. Two-component adhesives consist of an isocyanate prepolymer, which is cured with low equivalent weight diols, polyols, diamines, or polyamines. Such systems can be used neat or as solution. The two components are kept separately before apphcation. Two-component polyurethane systems are also used as hot-melt adhesives. 

DET-glycidyl adduct 25 10 min room temp. yes 75 fast cure adhesives laminating... 

The ability to tailor acrylic adhesives to fast cure times allows their use on fast, highly mechanized production lines such as those for audio speakers [150]. 

Different mixtures of anaerobic adhesives are available that offer a variety of curing times, strengths, and compatibilities. A typical cure time is 20 min for cure to begin, vibration resistance in about 1 h. Some fast cure systems will have about 20% cure in a few minutes and are almost cured in about 2 h. Some instant cure systems are ready for use within seconds. 

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). 

Amines are one of the most important curing agents for epoxy resins. They provide fast cures with a relatively high crosslink density. Unmodified amine cured epoxy resins are generally too brittle for adhesive applications, and so there are many derivatives that have been developed. More information on amine curing agents can be found in Chap. 5. 

This problem occurs when the liquid solidifies rapidly after being applied. An example is a fast-curing epoxy. Very fast-reacting epoxy adhesive systems that set in several minutes generally do not have the high adhesion strength that slower-curing epoxy systems have. One reason for this (there are others primarily related to the chemistry of these... 

A unique feature of these imidazole catalysts is that they do not have the high exotherm that dicyandiamide produces when cured in epoxy resins. Thus, they do not char or burn when exposed to high cure temperatures for fast cure. This is an important factor for adhesives that are cured via induction or dielectric heating. These adhesive systems are also much safer to ship via ah freight than conventional dicyandiamide catalyzed epoxy formulations due to their low exotherm. 

A fast-curing polymercaptan-epoxy adhesive formulation is shown in Table 11.11. The gel time for the mixed adhesive is about 8 min at room temperature. Tensile shear strength on aluminum is reported to be 2270 psi at 23°C. Note that the different color pigments used in parts A (carbon black) and B (titanium dioxide) are to assist by visually indicating when the two components are well mixed. 

Chain-Growth Polymerizations. Chain-growth polymerizations are very important to many commercially successful epoxy structural adhesives. They can be extremely rapid and contribute to the fast cure times needed for high productivity in many manufacturing operations. 

The incorporation of animal or vegetable protein constituents into phenolic resins to form exterior durable adhesives of fast-curing or special properties. 

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