Curable adhesive compositions and use thereof
A solvent-less hybrid curable composition is prepared from grafting polyesters or polyamides onto a (meth)acrylic copolymer backbone. Besides the many benefits of a solvent-less system, the hybrid curable composition forms strong adhesion to polar substrates, widens the use temperatures, and enables faster processing speeds than conventional hybrid curable compositions. The solvent-less hybrid curable composition forms an optically clear single phase that is suitable as tapes and labels, or in electronic, optoelectronic, OLED and photovoltaic devices, and the like.
1. A process forming a hybrid copolymer comprising the steps of:
a) copolymerizing an acrylic copolymer backbone comprising:
(i) a (meth)acrylic monomer,
(ii) a hydroxyl group containing monomer and
(iii) a cyclic compound having a polyester in the cyclic structure,
(iv) a third (meth)acrylic monomer that contains a photoinitiator group
b) opening the cyclic compound with a catalyst, whereby the cyclic compound is grafted on the acrylic copolymer backbone
wherein the process is solvent-free.
2. The process of claim 1 wherein the hybrid copolymer comprises:
(1) about 30 to about 99 wt % of the (meth)acrylic monomer;
(2) about 1 to about 30 wt % of the hydroxyl group containing monomer;
(3) about 5 to about 60 wt % of the cyclic compound; and
(4) up to about 10 wt % of the third (meth)acrylic monomer;
wherein the total wt % is 100 wt %.
3. The process of claim 1 further comprising the steps of:
(c) adding a UV-curable monomer, UV-curable resin, tackifier, plasticizer, photointiator, cross-linker, chain transfer reagent, and/or stabilizer; and
(d) irradiating the hybrid copolymer;
whereby a cured hybrid copolymer is formed.
4. The process of claim 2 further comprising the steps of:
(c) adding an isocyanate monomer, melamine crosslinker, tackifier, plasticizer, cross-linker, chain transfer reagent, and/or stabilizer; and
(d) thermally curing the hybrid copolymer;
whereby a cured hybrid copolymer is formed.