Hirofumi Okuyama

A New Flame Retardant 1,2-Polybutadiene Laminate

A flame retardant 1,2-polybutadiene laminate with excellent dielectric properties and high heat resistance has been developed for high density multilayer printed wiring boards. A high molecular weight 1,2-polybutadiene is selected as a base material to provide prepregs with a bnon-tacky property without semi-curing of the resin. A low molecular weight 1,2-polybutadiene is used to control the resin flow property of prepregs. The desirable flame retardation is achieved while maintaining the excellent dielectric and thermal properties of 1,2-polybutadieney using a new halogenated bisphenol methacrylate compound. The 1,2-polybutadiene laminate exhibits a low dielectric constant (¿ = 3.4) and dissipation factor (tan¿=0.004) and a flammability classification of UL94 V-1. Also, it has a solder resistance at 300°C for over 120 s. The 1,2-polybutadiene multilayer printed wiring board shows no occurrence of resin smears and excellent transmission characteristics, and demonstrates high reliability of interconnectionn between plated-through-holes and internal layers against thermal shock.

Holographic Recording Material Containing Poly-N-vinylcarbazole

A volume phase holographic recording material with high diffraction efficiency and high durability against humidity has been developed. The holographic material consists of Poly-N-vinylcarbazole (PVCz) as a base polymer, camphorquinone as an initiator and thioflavine-T as a sensitizer. This film is sensitive to argon ion laser light, and exposure energy of 500 mJ/cm2 is required to realize high diffraction efficiency. After recording a latent image of a fringe pattern by exposure, a hologram was developed by swelling and shrinking of the film with two sorts of solvent. The thickness of the hologram could be reduced to 2.5 μm, because the PVCz hologram has a large amplitude of the refractive index modulation related with the crystallinity modulation. The high diffraction efficiency coupled with the thin layer made an incident light angle wide enough to maintain a high diffraction efficiency around the Bragg angle.

Photoconduction of Copper Phthalocyanine-Binder Photoconductor Sensitized with Poly-N-vinylcarbazole

A nontoxic organic photoconductor for near infrared light has been developed. It consists of poly-N-vinylcarbazole (PVCz) dispersed in a copper phthalocyanine (CuPc)-binder resin system. PVCz has been selected from among several electron donating compounds that are considered to be able to reduce the induction period (TN) that is a typical imperfection of the binary system. The optimum mixing ratio of the three components (CuPc, PVCz, and a binder resin) was determined after examining film-forming ability, charge acceptance, and exposure energy for half-decay of the surface potential (E1/2). The photoconductor, composed of E-crystal form of CuPc (40 wt/%), PVCz (10 wt/%), and a polyester binder resin (50 wt/%), has an E1/2 of 3.2 , ¿J/cm2 at a light of 760 nm. It has a charge acceptance of 800 V, in accordance with the p-type. conduction of CuPc, when a positive surface charge is used.