High heat-resistant adhesive

Hot-melt-type (thermoplastic) polyimide films have been developed as high-heat-resistant adhesive materials. Mitsui Chemical s TPI, DuPont s Kapton KJ, Ube s Upicel, and Kaneka s Pixeo are typical examples. These are coated on dimensionally stable polyimide films to ensure good physical performance. 

The high heat resistance produced by adding phenolic resins to solvent-borne CR adhesives is due to the formation of the infusible resinate, which reduces the thermoplasticity of the adhesive and provides good bond strength up to 80°C (Table 11). The resinate also increases the adhesive bond strength development by accelerating solvent release. 4 phr of magnesium oxide for 40 phr of phenolic resin are sufficient to produce a room temperature reaction. A small amount of water (1-2 phr) is necessary as a catalyst for the reaction. Furthermore, the solvent... 

Catalytic curing agents (e g., tertiary amines) Long pot life High heat resistance Can be used as an accelerator or as the sole curative Long elevated-temperature cure Poor moisture resistance Rigid Adhesives Electrical encapsulation Laminates Powder coatings... 

A special feature of phenolic adhesives is the extremely high heat resistance of the adhesive layers, up to several hundred degrees centigrade. Therefore, they are widely used in car manufacturing for the bonding of brake discs and clutch linings on metal carriers. 

First made commercially available in Germany in 1936, this elastomer is officially known as acrylonitrile butadiene, and is usually the product of an emulsion polymerization process that combines the two monomers acrylonitrile and butadiene. However, the polymer can also be made in a solution process, and with a variety of monomers. As a specialty polymer, and even though several commercial brands were available, Buna N (as it was first known) was little used until World War II, when the polymer s unique oil and plasticizer resistance and high heat resistance became very important for transportation products. Nitrile rubber also exhibits exceptional adhesion to metallic surfaces and is compatible with a wide range of additives and compounding ingredients. 

Ethylene-acrylic acid ester copolymers show high heat resistance and high elasticity at low temperatures. Amorphous poly-a-oleflns (APAOs) are also used as the basic polymer and their main component monomer is propylene. They present better heat resistance than EVA. APAO shows good adhesion properties to nonpolar surfaces, good flexibility, and a high resistance to temperature and moisture. 

PPQ films discolor on heating, but retain their transparency and the major parts of their mechanical properties. To date, PPQs have been tested for application as high-temperature-resistant adhesives and as matrices for bonding materials. In such high-temperature applications, a postcuring must be applied whereby cross-linking occurs as a result of thermal or thermo-oxidative decomposition. 

Carboxylic acids are used as heat-curing coreactants in epoxy adhesives with reasonable room temperature latency. The cured adhesives typically demonstrate high heat resistance and relatively low moisture sensitivity. Epoxy cures with carboxylic acid curatives are generally somewhat sluggish, requiring high cure temperatures and/or base activators to achieve cures in reasonable time periods. 

Catalytic Very long pot life high heat resistance Long cure schedules at elevated temperature poor resistance to moisture Adhesives, electrical encapsulation, powder coatings, electrical laminates... 

Heat-Resistant Adhesives (Chapter 4), studies high-performance adhesives which display high heat resistance and are used in aerospace, aircraft construction, and we believe these adhesives will be used soon in other industries such as automotive, adhesives for mechanics, abrasives and industrial equipment. 

Pre-accelerated, low viscosity fast wet-out, thixotropic, low styrene emission, orthophthalic resin, offering good interlaminar adhesion, high heat resistance, improved water resistance and low exotherm enabling thick sections to be fabricated by either hand-lay or spray/projec ion techniques colour change on cure. Approved for food contact applications, Lloyd s and Det Norske Veritas. 

Recent low thermal stress encapsulation materials have been obtained by integrating many related advancements in materials sdem and engineering to achieve high purity, high adhesive and high heat resistance materials, with technology to lower thermal stress. Low thermal stress materials show excellent moisture resistance reliability even after solding. 

Thus the adhesion of highly dispersed lead dust to a cloth made from Nitron" fiber is smaller, i.e., the degree of purification is lower, than in the case of TsM cloth (mixture of 70% wool and 30% Capron), since the former has a less developed surface [396]. Yet the Nitron cloth has a high heat resistance, hydrophoby, and moisture resistance, which ensures good regeneration. The adhesive capacity of Nitron and other S5mthetic materials may be increased by giving them a special structure [397]. 

The sole attaching apphcation also needs the PUR adhesive due to its high initial strength, its high heat resistance and cold flexibility, excellent water resistance and fast chemical crosshnking as well as fast setting. 

A particular adhesive group used for high heat-resistant bonding is the single-component reactive adhesive, as a combination of phenolic resin and nitrile rubber, in the form of heat activated films (HAF). These contain latent hardeners for the phenolic resins, which are activated at a temperature of approximately more than 120°C. The advantages include clean and precise handling. 

During 1960—1970, an impressive number of heterocycles were engaged in macromolecules without taking into account their processability. At the present time, a few heterocyclic polymers have found general acceptance in the industry as heat-resistant adhesives, dielectric and insulating films, high-modulus fibers, protecting overcoats, and matrices for composites. The... 

When heat-resistant adhesives are applied by using the temperature and pressure recommended by the manufacturers, the adhesive properties at room temperature are generally very good, but the lap-shear strength at high temperature is significantly... 

A Methylolhydantoins. l,3-Bis(hydroxymethyl)-5,5-dimethyIhydantoia [6440-58-0] is used extensively as a preservative in cosmetic and industrial appHcations, and carries EPA registration for the industrial segment. It is available in soHd and in aqueous solution forms, including low free formaldehyde versions of the latter. A related derivative, l,3-bis(hydroxyethyl)-5,5-dimethyIhydantoia [26850-24-8] is used in the manufacture of high temperature polyesters, polyurethanes, and coatings, offering improved heat resistance, uv stabiUty, flexibiUty, and adhesion. 

Silicone resins with high phenyl contents may be used with medium or short oil alkyds as blends in air-dried or baked coatings to improve heat or weather resistance the alkyd component contributes to adhesion and flexibiUty. AppHcations include insulation varnishes, heat-resistant paints, and marine coatings. 

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