Paste adhesives types

Epoxies Powder, one and two-part liquids and paste Many types of resins available, providing wide spectrum of properties. Easy to compound. Low shrinkage and excellent dimensional stability. Good to excellent adhesion. May be cast or molded. Coatings, sealants, adhesives, solderless PC boards. 

E 1512 E 1555 E 1793 Test Methods for Testing Bond Performance of Adhesive Bonded Anchors Specification for Structural Paste Adhesive for Sandwich Panel Repair Standard Practice for Preparation of Aluminum Alloy for Bonding in Foam and Beam Type Transportable Shelters... 

Which adhesion promoter system should be used depends above all on the specified performance of the articles to be manufactured, the working conditions influencing preparation of the priming coat paste, the type of coating system used, and the time spent in the gelling channel. 

Paste adhesives. Paste adhesive formulations are produced by mixing the base resin with low-molecular weight diluents or solvents, if necessary, to reduce viscosity. Other prepolymer resins may be added and agitated until dissolved. Viscosity and temperature are continuously monitored and more diluents or resin added as required. Finally, one or more types of fillers are added and mixed and the viscosity of the mixture is adjusted. In incorporating the filler into the resin, best results are obtained when the filler is preheated... 

There are three main polymers presently used for structural adhesive bonding and they are phenolics, epoxies and urethanes. We can also include in our classification, the initial physical state of the uncured adhesive since it governs the type of application and curing conditions. Structural adhesives are manufactured in the form of films or pastes. The films are one-part adhesives, i.e., they contain a latent catalyst which requires heat for activation. Structural adhesive films are made in a number of different thicknesses and can either be supported (containing a scrim) or unsupported. In general, film adhesives require the application of pressure during cure in order to obtain ultimate properties. Paste adhesives are either one- or two-part materials. That is, pastes can either contain a latent heat activatable catalyst, or they can be a system which is separated into two parts, one of which contains the cur a t i ve/ca talys t. Two-part pastes cure at room temperature. In this section the chemistry of one-... 

Pastes, mastics Highly viscous single- or two-component materials that cure to a very hard or flexible joint depending on adhesive type. Does not run when applied. Shelf and pot life are often limited. Often applied via a trowel, knife, or gun-type dispenser one-component systems can be applied directly from a tube. Various types of roller coaters are also used. Metering-type dispensing equipment in the 2,500 range has been used to some extent. 

When the substrate was reinforced with carbon fibre, the plateau results obtained depended heavily on the type of adhesive being used Cytec-Fiberite film adhesive FM -73M (curing at 120°C) and room-temperature curing Loctite Aerospace paste adhesive EA 9309. The composite matrix chemistry exerted significantly less influence. 

Phenolic materials go back to the patents of Baekeland and are based upon the reaction of phenol and formaldehyde to yield a lower molecular weight resinous material that can be formulated with other resins and sometimes other curatives to yield a paste adhesive or a film adhesive. When phenol and formaldehyde are reacted in the presence of an acidic catalyst with an excess of phenol versus formaldehyde, they yield what are known as novolac resins. These materials are soluble in organic solvents and do not react further with themselves thus, they need to have a curative added. That curative is most often hexamethylene tetraamine. Another type of phenolic resin can be generated with an excess of formaldehyde and under basic conditions. These materials, known as resole phenolics, will react with themselves to yield a ftilly cured phenolic and thus must be stored frozen in order to limit this reaction. Thus, resole phenolics do not need an external CTOsslinker. Resole phenolics are widely used in the binding of paper products and the bonding of wood. Adhesives based upon these materials were brittle and could only be used to bond wood, where it is still widely used. A more widely usable adhesive was developed during World War II which modified the very brittle phenolic adhesive with poly(vinyl formal) resins. These materials were... 

Material that holds parts together by surface attachment. Examples include glue, mucilage, paste and cement. Various forms of adhesives include liquid or tape adhesives (physical type) and silicate or resin adhesives (chemical type). 

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