Heat set adhesive

Phenolic resins also find use in varnishes, electrical insulation, and in other protective coatings. Heat-settings adhesives which are based on phenolics find use in producing plywood. These also find use in the production of ionexchange resins having amine, sulphonic acid, hydroxy or phosphoric acid functional groups. 

Heat-setting adhesive A heat-setting adhesive is one that sets on the application of heat. For example, many epoxy resin mixtures may be kept cold to prevent the normal curing process that occurs at room temperature. 

East Japan Railway Company (JR-East) constructed a prototype train TRY-Z, which consisted of carbodies of three different type structures. A front car was made of thin-wall aluminum hollow extrusions welded continuously. The other front car had a monocoque sandwich structure in which aluminum honeycomb and plates were brazed. The middle car had a skeleton body stmcture of aluminum alloy joined by a combined method of spotwelding and adhesion by a heat setting adhesive. This method is called weldbonding. ... 

Urea resin adhesives, by the use of the proper hardener, may be set either by heat or at room temperature. For room temperature curing, the hardener may be ammonium chloride, together with basic materials like calcium phosphate to neutralize excess acid that might damage the wood. Cold set or room temperature set adhesives are those that set satisfactorily at 20 —30°C, whereas a hot set adhesive generally means one that is set above 99 °C. 

Heat-setting resins cannot be plasticized by low molecular weight plasticizers. Polyvinyl acetals have been claimed for these products. American Cyanamid Co. has suggested polyvinyl acetals or butyrals in an amount of 10 to 25% of the resin for urea and melamine resins. For varnishes and adhesives, combinations of phenolic resins and polyvinyl formal are recommended. Polyvinyl acetals with higher alkyl radicals are suitable for cellulose esters and improve elasticity as well as resistance against water. 

Backing and Tear-repair. The methods and materials proposed for lining include the following (a) mulberry paper attached with starch (rice or wheat), methylcellulose, or carboxymethyl-cellulose adhesives (18 19), (b) contemporary tapa attached with starch or cellulose-derived adhesives (20 21), (c) nylon laminating tissue and heat-set polyamide resin (22) and (d) stitched backings. 

Equation (5.7.5], and variants thereof, have been widely invoked to assess the surface tension of solid surfaces by working with organic liquids (such as hydrocarbons) in which dispersion forces prevail. For those one may set = y " so that the equation can be solved for y , which, in turn, may be equated to y for a Van der Waals solid. However, we see from [5.7.7] that the situation is more complicated. First, neglection of the TAS term is not allowed, it may account for 20-30% of the interaction Helmholtz energy. Second, even if an assumption is made on, or if it is directly measured from the heat of adhesion, only the... 

These at room temperature plastic/hard one-component systems are usually processed in adhesive melting drum installations. Adhesive heating occurs by means of heated panels that, depending on the consumption, continuously sink in the drum and heat the adhesive in layers until the curing reaction and viscosity reduction set in. The adhesive melt is pumped to the application appliances by thermally insulated hoses that are also heated. While the melt is solidifying, the final curing occurs in the glueline and results in an adhesive layer (just like a hot-melt adhesive, Section 5.1) due to the chemical reaction described in Section 4.1.1. 

In their processible mixture, these one-component products, also belonging to physically setting adhesives, consist of two components PVC (polyvinyl chloride-) particles and plasticizers (Section 9.2.9). The solid PVC particles are disperged in the high-viscosity plasticizer. The adhesive layer formation occurs by heating (120-180 °C), when the thermoplastic PVC swells and is thus able to absorb the plasticizer (no chemical reaction ). This process is called a sol-gel process. The formerly two-phase system (sol) is turned into a single-phase system (gel) by the inclusion of the plasticizer. 

Adhesive films Consisting of two-component reactive adhesives applied to a nonadhesive substrate for transport and storage purposes that is removed prior to processing. Curing occurs via chemical reaction under application of heat and pressure. Adhesive films are also commercially available as physically setting films, see heat-sealing adhesive. 

Chem. Descrip. Pentaerythritol ester of dimeric resin acids Uses Resin in fast-drying soft-oil varnishes, in prod, of flushed colors and resin-bonded pigments, in heat set printing inks requiring extreme hardness, high gloss, and sol. in low-KB ink oils, and inshort-open-time, heat-resistant hot-melt adhesives... 

Chem. Desap. Aromatic hydrocarbon resin Uses Tackifier, reinforcing agent, extender in rubber compding. and extruding applies., in metallic cold-cut paints, heat-set letterpress and web offset printing ink vehicles, food pkg. and processing food pkg. adhesives, rubber articles... 

Chem. Descrip. Modified aliphatic amine Uses Epoxy curing agent for laminates, fast-set adhesives, castings, and tooling compds. accelerator for Genamid 250,490,747 Features Offers faster cure times, lower reaction temps. exc. chem. and heat resist. 

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