Multi-component adhesives

ISO 10364 1993 Ed.1 BS 5350 Part B4 1993 Adhesives -Determination of working life (pot life) of multi-component adhesives. 

The multi-component adhesives are generally only used where the single-component types will not suit the application or the process needs. The principal uses of multi-component adhesives are discussed below. 

Due to production rate fluctuations within the industry, a long shelf life is required the multi-component system has, in this respect, a major advantage over the single-component system, whether the multi-component adhesive is ambient or elevated temperature curing. Addition of the catalyst at the dispensing stage ensures a long shelf life. 

The adhesive will be maintained in a sealed container at 20 "C for 24 h prior to its use. In the case of multi-component adhesives the individual parts will be held separately for this period prior to mixing. The mixing of these materials will be in accordance with the supplier s instructions. If a material cannot be held at this temperature without reacting, the advice of the supplier should be sought. 

FE data have been collected from the fracture of a wide variety of single and multi-component solids, ranging from single crystals of molecular solids to fiber-reinforced composites, and also from the peeling of adhesives 0-16 ). In this paper, we will restrict our attention to FE arising from the failure of polymer composites (fibrous and particulate), and the individual components thereof (fibers and matrix resins). 

Possibility for the preparation of multi-component alloys with concentrations of elements much higher than their equilibrium values. This is due to the fact that the film composition is mainly determined by the relative contents of components in the stream of sputtered atoms and by the adhesion factor, but is not defined by thermodynamic equilibrium. 

Uses Defoamer for stripping, foam knock-down, and latex handling for pressure-sensitive adhesives, gravure inks, paints defoamer for food-contact coatings, paper/paperboard food pkg. adhesives Features Easily dispersible multi-component very effective with ethylene copolymers and compds. 

This approach was further explored by Hakemi (2000) who prepared blends that contain both a wholly aromatic and an aromatic-aliphatic LCP that are miscible with each other. The ultimate goal of this approach was to develop multi-component blends that have components of thermoplastics. The miscible LCP blends could be useful as reinforcing agents for the thermoplastic matrix polymer and, due to the fact that the LCP s contain some of the components of the thermoplastic polymer, there is expected to be improved adhesion between the LCP portion and the matrix portion of the mixture. This is another example of an attempt to balance the phase separation that is inherent in high temperature polymer blends due to molecular conformation differences by strengthening the enthalpic interaction between the two polymers. 

Materials suitable for use as underwater adhesives include carefully formulated coldcuring thermosets such as Epoxide adhesives and Polyurethane adhesives. Such multi-component systems are not significantly affected by the presence of water in the uncured condition and convert from the liquid to the solid state via Chain polymerization in which two or more co-reactants form one polymeric product. The process does not involve the loss of solvents and does not require the presence of oxygen. 

ACI 503.1 Standard specifications for bonding hardened concrete steel, wood, brick and other materials to hardened concrete with a multi-component epoxy adhesive. 

HARDENED CONCRETE WITH A MULTI-COMPONENT EPOXY ADHESIVE 506R GUIDE TO SHOTCRETE... 

Pot life The pot life is the time during which a multi-part adhesive can be used after mixing the components. Synonym working life. 

To say that adhesion plays an extremely important role in the performance and durability of multi-component polymeric systems is a gross understatement. And even though everyone recognizes... 

Good adhesion compatibility is important in most multi-component technologies. This is obtained due to close chemical similarity. Non-adhesion is needed for movable doll limbs or venting grilles for car interiors. 

Elastomeric adhesives are natural or synthetic polymers with superior toughness and elongation. Examples of elastomeric adhesives include natural rubber, reclaimed rubber, butyl rubber, polyisobutylene, nitrile rubber, styrene-butadiene-rubber, etc.l Elastomeric adhesives are supplied as solvent solutions, latex cements, pressure sensitive tapes, and single- or multi-component nonvolatile liquid or pastes.[ 1 However, they are usually supplied in liquid form. Most are solvent dispersions or water emulsions. The service temperature is up to 204°C (400°F). They never melt, have excellent flexibility, but low bond strength. The main application of elastomeric adhesives is on unstressed joints on lightweight materials (e.g., joints in flexure). Hence, they are not considered structural adhesives. 

In order to achieve this state, many of these adhesives are reactive, i.e. multi-component systems which, after application to the adherend, change their physical format from liquidus to infusible solid by chemical reaction. These polymerisation and cross-linking reactions, often thermally induced, are achieved using one or more of the following reaction mechanisms ... 

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