Japanese Patent JPS538593

B2

Regeneration of spent PTFE takes place by radiation-induced graft block copolymerisation of spent PTFE with >=1 fluorinated monomer having formula: C2-FxR4-x (I) (where x is 1-4 when R is H; x is 3 when R is CF3, Cl1, C6F5 or Ph). Process comprises activating a powder of spent PTFE having particle size 100 mu, or of a suspension of the powder in water or in (I), by ionising radiation, in an atmos. of >1 (I), of inert gases under press 5 Torr. or in vacuo not exceeding 1 x 10-2 Torr. Integral radiation dosage is 1 x 10-6 rad, applied at 1 x 10-2 to 1 x 102 rad/sec. Process takes place under 2 x 10-3 vol. % O2 content, at -196 to +100 degrees C and under a (I) press. of 10-1 to 50 atmos. Ionising radiation may be used as gamma-, X-ray, beta- or UV-radiation or accelerated electrons. When using spent PTFE, as powder, activation pref. takes place by plasma treatment. PTFE scrap or waste can be used to form a new class of thermoplastic graft copolymers. Regeneration can be achieved with a fluorinated monomer consumption of 5-50 wt. % w.r.t. spent PTFE. Radiation dosage increases from 1 x 10-2 to 10 rad/sec. for C2F4 as (I), to 1 x 10-1 to 50 rad/sec. for (I where x = 1-3, R = H; x = 3, R = Cl) and to 1 to 1 x 102 rad/sec. for mixts. of (I where x = 1-4, R=H; x = 3, R=Cl) with C2H4, C2H3Cl, (I where x = 3, R = CF3, C6F5, Ph). In an example, 50 g PTFE in aq. suspension were treated with C2F4 at 70 degrees C, 1 x 10-2 rad/sec. for 20 hrs. Wt. increase was 8.1g.

JP9573175A

March 30, 1978

August 06, 1975

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C08F14/00; C08F259/00; C08F259/08; C08F293/00; C08J11/04

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