摘要:
Process for preparing a macromonomer using free radical-initiated aqueous emulsion polymerisation in a polymerisation reactor of at least one olefinically unsaturated monomer, which process employs a hydrophobic Co chelate complex as a CTA, a stabilising substance(s) for the emulsion polymerisation process and a monomer feed stage MF;wherein an aqueous pre-emulsified mixture A, comprising at least part of the Co chelate(s) employed, at least part of the stabilising substance(s) employed, and (i) a non-polymerisable organic solvent(s) and/or (ii) a polymerisable monomer(s) in unpolymerised or at least partially polymerised form, is contacted in the reactor with monomer(s) of feed stage MF at the beginning of and/or during the course of feed stage MF; and wherein in mixture A the weight ratio of (i) and/or (ii) to the stabilising substance(s) is in the range of from 10/1 to 1/10.
摘要:
There is described a formaldehyde-free laminating adhesive, optionally the with less than 3% by weight of co-solvent(s), the adhesive comprising: (I) a polyurethane that comprises from 30% to 65% by weight of hard segments, the polyurethane being obtained and/or obtainable from a first polyurethane dispersion (PUD) comprising the reaction product of (A) an organic isocyanate and (B) at least one chain extender reacting in a respective stoichiometric ratio (NCO to NCO reactive group) from 1:1 to 1:2.5 and; optionally the NCO reactive group(s) of the chain extender comprises one or more hydrazinyl-like group(s) (denoting isocyanate reactive groups selected from the group comprising, preferably consisting of: —NRNR2 (hydrazinyl groups); —CONRNR2 (hydrazidyl groups), —NRCONRNR2 (semicarbazidyl groups); and —ONR2 (oxyamine groups), where each R is independently selected from H or C1-10hydrocarbo); and (II) optionally a second polymer obtained and/or obtainable from a polymer precursor comprising at least one unsaturated moiety, preferably an ethylenically unsaturated group, and where optionally the second polymer may be iminated; with the provisos that: (α) when the first polyurethane does not comprise hydrazinyl-like group(s) then the second polymer is iminated; and (β) when the second polymer is un-iminated or is absent then the first polyurethane comprises hydrazinyl-like group(s). These adhesives may be used to adhere surface veneers to wood and/or to laminate the layers within plywood.
摘要:
An aqueous composition comprising at least one vinyl graft copolymer (A) and at least one vinyl polymer (B) obtained by a process comprising steps a) polymerising at least one vinyl monomer to obtain at least one macromonomer with a Tg1>15° C.; b) polymerising at least one vinyl monomer in the presence of the macromonomer prepared in step a) to form a polymeric backbone of said vinyl graft copolymer (A); c) polymerising at least one vinyl monomer in the presence of the vinyl graft copolymer (A) prepared in step b), to form said vinyl polymer (B); and where vinyl polymer (B) has a Tg2 lower than the Tg1 of the macromonomer.