Polyimide Laminating resin

Laminate materials, properties of, 17 844t Laminates, 26 752-754 electrical, 10 453—451 fabrication of, 20 112 polyimide, 20 285 printed circuit board, 17 843 strength of, 26 782-783 Laminating, ceramics processing, 5 655 Laminating resins, amino acid resins, 2 630-631... 

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... 

Aromatic polyimides have achieved considerable success as high temperature-resistant polymers. Since the desired high molecular weight polyimides are not readily processable, they are generated in situ by the thermal ring closure of the processable precursor poly(amic-acids) ( 2). The use of low molecular weight prepolymers, i.e. poly(amic-acids), as laminating resins is limited by their conversion to an intractable state before complete elimination of volatile by-products. 

Thermid . [Nat l. Starch ft Chem.] Polyimides thermosetting resin for laminating, composite prepregs, molding, coatings, adhesives (strucu and etetronic). 

Furthermore, the overall properties of the base materials for circuit boards are determined essentially by the joint between the copper foil and the laminate. This joint can be realized by both an added adhesive and by the laminating resin itself, which additionally, acts as adhesive. An additional adhesive is needed in the manufacture of flexible circuit boards (e.g., polyimide/copper) or of paper-based rigid circuit boards. During this process the adhesive is deposited on the bottom side of the copper foil after... 

The historically-firet condensation polyimides have recently been complanented by a second class of resins - addition-type polyimides. KINEL conqpounds and KERIMID 601 laminating resin are menbers of this new family of polyimides. Ch ically they eure designated polyaminobismaleimides (PABMs) ... 

Common laminating resins used are phenolic and epoxy, although cyanate esters, polyimides, and other resins are used in specialty applications. The copper foil used is 99.5 percent pure and may contain some silver. Generally, electrodeposited foil is used rather than rolled copper, and the foil is usually treated to improve the adhesion of the laminating resin to the foil surface. 

The most common thermosetting laminating resins are phenolics, melamines, epoxies, polyesters, silicones, and polyimides. Thermoplastic resins used in making laminates include polysulfone, polyphenylene sulfide, polyetheretherketone, polyamide-imide, polybutylene terephthalate, nylon 6, and polypropylene. 

Polyimides which are available as both laminating resins and flexible films are used in military and aerospace applications where high temperature performance is critical. 

Silicon—Ca.rbon Thermoset. The Sycar resins of Hercules are sihcon—carbon thermosets cured through the hydrosilation of sihcon hydride and sihcon vinyl groups with a trace amount of platinum catalyst. The material is a fast-cure system (<15 min at 180°C) and shows low moisture absorption that outperforms conventional thermosets such as polyimides and epoxies. Furthermore, the Sycar material provides excellent mechanical and physical properties used in printed wiring board (PWB) laminates and encapsulants such as flow coatable or glob-top coating of chip-on-board type apphcations. 

Laminates produced by impregnation of glass and carbon fibre with polyimide resins followed by subsequent pressing have found important uses in the aircraft industry, particularly in connection with supersonic airliners. Such laminates can be used continuously at temperatures up to 250°C and intermittently to 400°C. 

Methods of preparation of the laminates depend on the partieular grade of polyimide resin used but in one process the polyimide precursor is dissolved in acetone and this solution is used to impregnate the glass or carbon fibre and thus produce a pre-preg . The pre-preg is dried and then pre-cured at about 200°C for about 3 hours. This operation reduces the volatile content and also modifies the flow properties to make them more suitable for the subsequent... 

One resin based on the BTDA/ODA backbone and 2-aminobiphenylene as an endcapper was thought to be such a resin (126). High quality laminates could be fabricated, but the Tg of the crosslinked polymer was lower than expected and therefore thermal oxidative stability was poor. The chemical structure of this thermosetting polyimide is given in Fig. 42. 

JP 05125345 (Japanese) 1993 Poly(vinyl butyral) blend adhesive composition for flexible printed circuit boards Ube Industries, Japan H Inoe, S Takabayashi, T Muramatsu, T Funakoshi Formulated resins having good flexibility and heat resistance are useful adhesives for polyimide/Cu foil laminated circuit boards Maleimide-terminated siloxane-imide block copolymers were formulated with poly(vinyl butyral) and melamine resins to give adhesive compositions. 

BPA/DC was compounded with high-temperature resistant ladder and semi-ladder polymers. A composition, which contained BPA/DC, a polyimide resin, organic Zn salt and benzyldimethylamine in A -methylpyrrolidone solution was described. The binder was destined for the manufacture of copper clad laminates. Tg of the cross-linked material was 265 °C [50]. Another example is a binder obtained from BPA/DC and polyphenylquinoxaline in chloroform [51]. 

In addition to the polymer substrate, a series of binding resins made from polyamide and polyimide, polyphenylsulfide (PPS), polyether sulfone (PES) and/or silicone resin are necessary for applying the coating. Such substances like laminating agents (lithium polysilicate, aluminum phosphate and phosphoric acid) and various additives are also used. Included in these additives are emulsifiers and further processing aids (e.g. silicone oil). 

Polyimides for microelectronics use are of two basic types. The most commonly used commercial materials (for example, from Dupont and Hitachi) are condensation polyimides, formed from imidization of a spin-cast film of soluble polyamic acid precursor to create an intractable solid film. Fully imidized thermoplastic polyimides are also available for use as adhesives (for example, the LARC-TPI material), and when thermally or photo-crosslink able, also as passivants and interlevel insulators, and as matrix resins for fiber-reinforced-composites, such as in circuit boards. Flexible circuits are made from Kapton polyimide film laminated with copper. The diversity of materials is very large readers seeking additional information are referred to the cited review articles [1-3,6] and to the proceedings of the two International Conferences on Polyimides [4,5]. 

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