WPBG-345

Physical characteristics

Color Appearance	nearly white crystals
Melting point/freezing point	138℃
Solubilities	water, diisopropyl ether : practically insoluble,or insoluble. ethyl acetate : freely soluble. no data available
TG-DTA	weight loss from 231℃
Solubility	(g/solv. 100 g) NMP62 GBL81 PGMEA55 Acetone107 Ethyl lactate31 PGME44 Methanol3 H2O<0.5

UV(0.02 mg/mL in CH₃CN)

Absorption maximum
197 nm(ε=118000) 254 nm(ε=15500) 365 nm(ε=15)

※When used in combination with a sensitizer, it shows photosensitivity even in the long wavelength region.

Related laws and regulations

TSCA	Not Listed
EINECS	Not Listed
REACH	Not Listed

Stability of compositions as pot life

●Possible to use sensitizer in order to irradiate @365 nm and longer wavelength.
●higher stability of pot-life than WPBG-300.

Example of Use 1Anionic UV curing of epoxy oligomer × polyfunctional thiol

Conditions

Preparation	Mix 3-10 parts of WPBG-345, 0.6-2 parts of 2-isopropylthioxanthone (0.2 equivalent amount to WPBG), and 100 parts of jER®828 (epoxy equivalent of 185, Product of Mitsubishi Chemical Corporation), and heat or use a diluent to promote dissolution. Mix 70 parts of KarenzMT®PE1 (SH equivalent of 138.5, Product of Showa Denko K.K.) at room temperature.
Stability of components as pot life (period in which the viscosity does not exceed the twice of the initial viscosity)	2 month or more (10°C), 3 weeks (25°C), and 3 days (40°C)
Exposure	Irradiation for 10 seconds (Illuminance: 5mW/cm2 (254 nm), 100 mW/cm22 (365 nm), and 261 mW/cm2 (405 nm))

Example of Use 2Patterning by epoxy oligomer × carboxylic acid

Conditions

Preparation	Mix 1-10 parts of WPBG-345, 0.2-2 parts of 2-isopropylthioxanthone (0.2 equivalent amount to WPBG), and 100 parts of jER®828 (epoxy equivalent of 185, Product of Mitsubishi Chemical Corporation) and 64 parts of Joncryl®682 (OH equivalent of 138, Product of BASF Japan Ltd.) into 300 parts of γ-butyrolactone.
Film-forming	Polycarbonate, film thickness: 10-20 μm
Exposure	Optional (Illuminance: 5mW/cm2 (254 nm), 100 mW/cm2 (365 nm), and 261 mW/cm2 (405 nm))
Post-exposure bake	150°C/10 minutes
Development	1 wt% Na2CO3, Immerse for 1 minute → rinse with water.

Photo sensitizer effective for borate-type photo base generators (PBG)

WPBG-300 and WPBG-345 can generate alkyl biguanide under a wide range of wavelength by used with photo sensitizers such as thioxanthone which can be absorbed in long-wavelength (Fig.1). Since photodegradability of PBG changes depending on the type of photo sensitizer, it is necessary to select the optimal sensitizer by taking into consideration the light source, coloration after curing and other conditions.

Fig.2 shows the photo-decomposition rate when WPBG-345 is used combined with different photo sensitizers.
2-Ethylanthraquinone and 1-Chloroanthraquinone show high photo sensitizing effect and contribute to improvement of photodegradability of WPBG-345.

To use 2-Ethylanthraquinone as a photo sensitizer for epoxy oligomer/multifunctional thiol makes the curing time shorter than to use 2-Isopropylthioxanthone. Similarly, to use 2-Ethylanthraquinone for WPBG-300 makes the photodegradability improved.

Mix 3-10 parts of WPBG-345, 0.2-1 parts of sensitizer, and 100 parts of jER®828 (epoxy equivalent of 185, Product of Mitsubishi Chemical Corporation), and heat or use a diluent to promote dissolution. Mix 70 parts of KarenzMT®PE1 (SH equivalent of 138.5, Product of Showa Denko K.K.) at room temperature. Irradiate for 10 seconds (Illuminance: 5mW/cm2 (254 nm), 100 mW/cm² (365 nm), and 261 mW/cm² (405 nm)), and heat at 120℃.