Antistatic permanent coating prodn. on photographic material with poly:thiophene - by oxidative polymerisation with at least stoichiometric amt. of peroxy acid salt and desalination for high yield avoiding haze by dendrite formation

摘要

Prodn. involves the use of a polythiophene (I) obtd. by oxidative polymerisation of thiophene (II) with a salt (III) of a peroxy-acid, (I) applied as aq.(organic) formulation and dried. (A) oxidative polymerisation is in the presence of at least 1.0 mole. (III)/mole. (II); and (b) the aq. formulation obtd. is freed from over 60% of the inorganic salt content. The antistatic coat is pref. covered with a top coat. USE/ADVANTAGE - (I) is used for permanent antistatic coats. The prodn. is economic and the films have higher conductivity c.f. usual, since almost quantitative oxidn. of (II) is obtd. by increasing the amt. of (III) and desalination prevents problems in filtration and haze by dendrite formation. In an example, air was introduced into a soln. of 20 g polystyrene sulphonic acid (Mn = 40000), 5.6 g 3,4-ethylene dioxy-thiophene, (1) 2.7, (2) 8.1 g K2S2O8 (10 mmole.) and (1) 25, (2) 50 mg Fe2(SO4)3 in (1) 972, (2) 966 ml water for 24 hr. at room temp.. After filtration, the blue soln. of 3,4-polyethylene dioxy thiophene-polystyrene sulphonate contained (1) 2.1, (2) 3.2% solids. 500 ml soln. (2) were diluted with 250 ml water and salinated by ion exchange, giving a 1.6% soln. contg. only 0.4 g/l K ions and 5 mg/1 SO4 ions, i.e. 74% ions and 99% SO4 ions were removed. Cellulose triacetate film was coated with solns. prepd. from (A( 14.3, (B) 6.6, (C) 3.3 ml. soln. (1) (not desalinated) or (D, E) 4.7 ml. desalinated soln. (2), (A) 10.7, (B) 18.4, (C) 21.7, (D) 20.3, (E) 5.3 ml water, (A, B, C, D) 10, (E) 35 ml MeOH and 65 ml acetone, which has a viscosity of (A,D) 2.3, (B) 2.2, (C) 2.1, (E) 1.3 mPa.s. The wet thickness was (A, B, C, D) 25, (E) 20ml/m2. All samples are given a top coat (cellulose diacetate + dispersed polyethylene). The surface conductivity at 50% RH was before/after processing was (A) 6x10power-6/6x10power-7, (B) 8x10power-10/6x10power-11, (C) 3x10power-2/2x10power-power13, (D( 4x10power-6/3x10power-7, (E) 3x10power-6/2x10power-7 ohm/sq.; and the amt. of coating removed during processing (A) 15, (B) 10, (C) 2, (D) 5, (E) 0%