Poly imide adhesive

After cleaning by abrasion and with solvents, the polyimides can be stuck with a poly-imide, epoxy or acrylic resin adhesive whose thermal resistance is compatible with the operating conditions. Preliminary tests are essential. 

Addition poly(imide) oligomers are used as matrix resins for high performance composites based on glass-, carbon- and aramide fibers. The world wide market for advanced composites and adhesives was about 70 million in 1990. This amounted to approximately 30-40 million in resin sales. Currently, epoxy resins constitute over 90% of the matrix resin materials in advanced composites. The remaining 10% are unsaturated polyester and vinylester for the low temperature applications and cyanate esters and addition poly(imides) for high temperatures. More recently thermoplastics have become important and materials such as polyimides and poly(arylene ether) are becoming more competitive with addition polyimides. 

Bott RH, Summers JD, Arnold CA, Blankenship CP Jr, Taylor L T, Ward TC, McGrath JE (1988) Poly(imide siloxane) segmented copolymer structural adhesives prepared by bulk and solution thermal imidization. SAMPE J 24(4) 7... 

Yoon TH, Arnold-McKenna CA, McGrath JE (1992) Adhesion behavior of thermoplastic polyimides and poly(imide siloxane) segmented copolymers influence of test temperatures J Adhes 39(100) 15... 

Kaltenecker-Commercon JM,Ward TC, Gungor A, McGrath JE (1994) Water resistance of poly(imide siloxane) adhesives diffusion coefficients by gravimetric sorption. J Ad hes 44 1,85... 

Regnlus. [Advanced Web Prods.] Poly-imide thermoplastic film heat-resistant film for wire and cable, thermoplastic composites, pressure-sensitive adhesive Ugrra, primary insulation. 

Almost all film adhesives used in electronics assembly are either epoxies or poly-imides on a glass fabric carrier. Eihn adhesives may be thermoplastic or thermosetting... 

The incorporation of pyridine or triazole improves the adhesion between poly(imide)s and copper.Poly(3,3, 4,4 -benzophenone tetracarboxylic dianhydride-3,5-diamino-l,2,4-triazole) (BTDA-DATA) contains the triazole moiety as repeating units. Poly(4,4 -oxydiphthalic anhydride-1,3-aminophenoxybenzene-8-azaadenine) (ODPA-APB-8-AA) bears the triazole moieties at the end." BTDA-DATA starts to decompose at 350°C. However, ODPA-APB-8-AA starts to decompose at 400°C. The polymers have been tested as adhesives for copper surfaces. The adhesion is increased by the formation of copper complexes. 

Oxydianiline was separately mixed with 2,6-diaminopyridine and 3,5-diamino-1,2,4-triazole, to form a mixture of diamines. Then poly-(imide)s (PI)s were synthesized by reacting the mixture of the diamines and pyromellitic dianhydride. The adhesion strength of sputter-deposited copper to PI films is proportional to the content of functional groups." ... 

This material can withstand a standard steam sterilization. On the other hand, the adhesion to gold and poly(imide) could not be improved satisfactorily. Thermal annealing causes more brittle and stiffer films... 

A poly(imide-siloxane)/titania hybrid film was fabricated by a sol-gel process by the in situ formation of titania within the poly(imide-siloxane) matrix [85]. The poly(amic acid siloxane) polymer was prepared from 4,4 -oxydiphthalic anhydride, 2, 2-bis [4-(4-aminophenoxy) phenyl] propane, and a,a>-bis(3-aminopropyl)polydimethylsiloxane. Acetylace-tone was used as chelating agent in order to reduce the rate of hydrolysis of titanium alkoxide in the polymer. The presence of titania on the surface of eventually produced films enhances the adhesive strength at the interface. 

Ko CJ, Tseng IH, Whang WT, Tsai MH. Effect of 1102 on thermal and adhesive characteristics of poly(imide siloxane)/Ti02 hybrid films. J Appl Polym Sci 2012 124(3) 1929-37. 

Oligomers end-capped with maleimide rings, which are known as bismaleimide (BMI) resins, exhibit thermal stability intermediate between epoxies and poly-imides. BMI systems are mainly used to fabricate structural composites capable of sustaining temperatures up to 230°C. Specific versions, such as American Cyanamid FM 32 and Ciba-Geigy Kerimid 601 have been developed to prepare adhesive compositions. Fig. 17 displays a typical constitutive unit of various commercial BMI resins based on bismaleimide 38, prepared from maleic anhydride 37 and 4,4 -methylenebisbenzeneamine (MDA) 34. 

AF 131, based on epoxy-phenolic resins, provides Al/Al bonds with lap shear strengths of 25.5, 20 and 10.3 MPa at 180, 200 and 260°C, respectively. Solventless epoxy and epoxy-phenolic adhesives provide bond lines with a low level of porosity. This is also the case with poly(ether-imide) Ultem 1000 and poly(imide-siloxanes), which are generally processed at temperatures 50-100°C above their Tg. In contrast, high porosity is observed with most condensation... 

Because sputtering deposition covers the sloped wall of vias, this technique is also suitable for the metallization of vias patterned in a photosensitive dielectric, vias formed through laser ablation, and wet-etched vias in poly-imide. However, it is difficult to sputter a thick metal film, because stress in the deposited film leads to poor adhesion. The typical metal thickness is around 2 pm. Therefore, the vias are partially filled and a staircase or staggered via layout is normally used, which limits interconnect density. In addition, the interconnect lines have sloped sidewalls because both vertical and lateral etching occur in the wet-etching process. 

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