Heat-resistant adhesives

Handbook of Adhesives and Sealants Volume 2 P. Cognard (Editor) 

V isoindoledione (imide), VI pyrroledione or maleimide, VII bicycloheptylpyrroledione or nadimide, VIII quinoline, IX benzoxazine, X quinazoline, XI quinoxahne. 

Some examples of heterocycles incorporated in polymer repeating units are provided in Fig. 1 to illustrate the versatility of the chemistry explored over the last few decades. 

The basic chemistry of aromafic polyimides was first disclosed in patents filed by Du Pont de Nemours [5] for polypyromellitimides and later on by Edwards [6, 7] for polyimides prepared with various aromatic dianhydrides and diamines. They compose 

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 

Handbook of Adhesives and Surface Preparation, ed. Sina Ebnesajjad. DOI 10.1016/B978-1-4377-4461-3.10009-4 2011 Elsevier Inc. All rights reserved. 

This chapter has been reproduced from Heat-Resistant Adhesives in Handbook of Adhesives and Sealants, Volume 2, Cognard 2006 Elsevier Ltd. 

Heat-resistant polymers were initially developed for aerospace uses requiring a continuous service temperature of approximately 260 °C. However, legislation on energy efficiency and safety requirements continues to expand the market potential, in 

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Glass transition temperatures were determined refractometrically, as described by Wiley (20), with an Abbe refractometer supplied by Bellingham and Stanley. This instrument can normally be used only at temperatures up to 70°C. The prisms of this instrument were coated with a heat resistant adhesive (epoxy-phenolic resin mixture). After this modification the refractometer can be used at temperatures up to 200°C. 

JP 05306386 (Japanese) 1993 Heat-resistant adhesive composition Ube Industries, Japan H Inoe, S Takabayashi, T Muramatsu, T Hirano Resin formulation useful for bonding Cu foils to polyimide films for electronic applications Heat-resistant adhesives were formulated to include imide-siloxanes with softening points <300° C. Diaminopolysiloxanes and aromatic amines were used maleimide termination also utilized. 

JP 05311144 (Japanese) 1993 Heat-resistant adhesive compositions containing polyimide-siloxane block copolymers Ube Industries, Japan H Inoe, S Takabayashi, T Funakoshi, K Sonoyana Useful for Cu-clad laminates of printed circuit boards and tape-automated bonding with good flexibility and heat resistance Formulated compositions containing siloxane-imide block copolymers made from aromatic tetracarboxylic acids and aromatic diamines and aminosiloxanes... 

JP 62246978 (Japanese) 1987 Heat-resistant adhesives containing siloxanes and imide-containing resins Shin-Etsu Chemical Industry Co. Ltd., Japan S Ueno, N Nakanishi, S Hoshida Adhesives showed good adhesion and flexibility useful in the preparation of flexible laminates Resin was prepared from the reaction product of bismaleimides, diamines, amino-terminated siloxanes and a bisphenol A cyanate adduct. The adhesive formulation was used on polyimide films... 

Inoue H Takabayash S Muramatsu T, Funagoshi T, Hirano T. Polyimide-siloxane block copolymer-based heat-resistant adhesive compositions. US Patent 5180627 A 930119 11 pp... 

A similar concept based on a mixture of BMI-MDA (Matrimide 5292 A) and bis-alkenylphenol (Matrimide 5292 B) with a flexible polyimide has been patented as a heat-resistant adhesive [117]. 

Epoxy resins are superior in heat resistance, adhesion, corrosion resistance and also mechanical properties among thermosetting resins and are widely used for coatings, adhesives, electric insulating materials and matrices for FRP in areas such as aircrafts, electronics, electric power, and building and civil engineering. 

More recently Nicholas and Gmitter [23] prepared heat-resistant, rigid poly-isocyanurate foams and Sandler [24] reported on a similar process to prepare heat-resistant adhesives for aluminum. The trimerization agents reported by Sandler [24] were various metal salts and organometallic compoimds such as tri-n-butylantimony oxide [25] as shown in Table X. 

Figure 1 Sequence of development of heat-resistant adhesives. (Adapted from Ref. 23.)...

Uses Encapsulation of electronic parts elec, insulation gaskets surgical membranes and implants automotive engine components miscellaneous mech. parts textile/fiber softener and finishing agent heat-resist. adhesives caulks/sealants rubber for food-contact articles for repeated use... 

In view of the above efforts, it is surprising that the majority of recent patents on adhesives are for solvent-based systems.The new inventions include a universal primer, an adhesive composition in which solvents have been selected based on Snyder s polarity (only solvents which belong to group III are useful in adhesive for automotive applications to avoid a deleterious effect on paint), a low VOC adhesive for pipes and fittings, a solvent-containing heat-resistant adhesive based on siloxane polyimide, a water-based polyimide adhesive,and two-component solvent-free polyurethane adhesive system for use in automotive door paneling. ... 

The combined use of an epoxy compound and an oxetane compound markedly increases the rate of polymerization (37). In addition, oxetane compounds have excellent heat resistance, adhesive properties, and chemical resistance. Oxetane compounds are summarized in Table 3.21 and some compounds are shown in Figure 3.20. 

Ohkawa, Y. Sakata, Y Okumura, T. Shibuya, A. Kuroki, T. Oikawa, H. Poly (amic acid) copolymers, polyimide copolymers, and heat-resistant adhesives therefrom. Jpn. Kokai Tokkyo Koho JP 11217435, 1999 Chem. Abstr. 1999,131, 158564. 

Several adhesion promoters were described in Section III.A.2.a., but only a few of these are heat-resistant adhesion promoters. One of these is itaconic anhydride which has been shown to improve the heat resistance of allyl cyanoacrylate. As shown in Table X, BTDA is an effective heat resistance promoter and other anhydrides from ref. 79 may also be effective. Recently, phthalic anhydride was described as a heat and moisture resistance promoter for cyanoacrylates. These patent examples illustrate the effect... 

The discussion of heat durability in this section should make clear that this is a complex phenomenon. Embrittlement, retropolymerization, thermoplasticity, and the loss of adhesion are all factors affecting the adhesive s performance on metal surfaces. Based on the published state of the art, optimum cyanoacrylate heat durability could be achieved using a combination of a heat-resistant adhesion promoter, a crosslinking agent, and a plasticizer. The heat durability promoters discussed in this section are summarized in Table XI. 

Adhesive tape For keeping detail elements of the set-np in place dnring cure, it is common to use specialized, non-contaminating and heat-resistant adhesive tape. 

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