Initiators for optical coating formulations with reduced yellowness
View Patent ↗The invention relates to a acrylated-based optical coating composition containing an organic peroxide initiator which presents a low yellowness level. The initiator has a range of free radical energy that is below a predetermined level. The cure process is controlled by the use a catalyst and a low energy initiator to avoid deleterious reactions that can increase yellowness. The composition is well suited to be applied to a lens and cured in the mold to form a coating with reduced yellowness having high adhesion and abrasion-resistant properties. A dye can be introduced into the composition to form a tinted lens.
1. A thermoset composition comprising:
(1) at least one monofunctional (meth)acrylate;
(2) at least one multifunctional (meth)acrylate;
(3) at least one difunctional meth(acrylate);
(4) at least one aliphatic urethane diacrylate;
(5) at least one metal salt; and
(6) at least one initiator comprising an organic peroxide which presents a free radical energy less than about 113 kcal/mol at 298 K, wherein said initiator being selected from the group consisting of t-amylperoxy-2-ethylhexylcarbonate and t-butylperoxy-2-ethylhexylcarbonate.
2. A thermoset composition of claim 1 , further comprising at least one dye selected from the group consisting of a cosmetic dye, tint dye, a photochromic dye, a dichroic dye and combinations thereof.
3. A thermoset composition of claim 1 , further comprising one thermoplastic polyurethane (TPU).
4. The composition of claim 1 , wherein the monofunctional (meth)acrylate is selected from the group consisting of isobornyl acrylate, isobornyl (meth)acrylate, methyl methacrylate, benzyl methacrylate, benzyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, 2-phenoxyethyl methacrylate, 2-phenoxyethyl acrylate and combinations thereof.
5. The composition of claim 4 , wherein the monofunctional (meth)acrylate is benzyl acrylate.
6. The composition of claim 1 , wherein the multifunctional (meth)acrylate is selected from the group consisting of dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, hexafunctional aliphatic urethane acrylate, and combinations thereof.
7. The composition of claim 6 , wherein the multifunctional (meth)acrylate is dipentaerythritol pentaacrylate.
8. The composition of claim 1 , wherein the difunctional (meth)acrylate is selected from the group consisting of 1,6-hexanediol diacrylate, ethoxylated bisphenol A di(meth)acrylate, polyethylene glycol di(meth)acrylate and combinations thereof.
9. The composition of claim 1 , wherein the metal salt includes cobalt naphthenate.
10. The composition of claim 1 , wherein the initiator has the highest free radical energy below about 106 kcal/mol at 298 K.
11. The composition of claim 1 , further comprising:
(1) said at least one monofunctional (meth)acrylate being present in an amount from 5% to 40% by weight;
(2) said at least one multifunctional (meth)acrylate being present in an amount from 5% to 50% by weight;
(3) said difunctional meth(acrylate) being present in an amount from 5% to 50% by weight;
(4) said aliphatic urethane diacrylate being present in an amount from 5% to 70% by weight;
(5) said at least one metal salt being present in an amount from 0.05 to 2.0 phm; and
(6) said initiator being present in an amount from 0.1 to 5.0 parts per hundred monomer (phm).
12. A thermoset composition comprising:
(1) at least one monofunctional (meth)acrylate;
(2) at least one multifunctional (meth)acrylate;
(3) at least one difunctional meth(acrylate);
(4) at least one aliphatic urethane diacrylate;
(5) at least one metal salt;
(6) at least one initiator comprising an organic peroxide; and
(7) a thermoplastic polyurethane (TPU) being present in an amount from 0.5 to 5.0 parts per hundred monomer (phm).
13. The composition of claim 2 , further comprising said at least one dye being present in an amount comprised from 0.1% to 5.0% by weight.
14. The composition of claim 1 , further comprising:
(1) said at least one monofunctional (meth)acrylate being present in an amount from 10 to 20% by weight;
(2) said at least one multifunctional (meth)acrylate being present in an amount from 10 to 35% by weight;
(3) said difunctional meth(acrylate) being present in an amount from 10% to 35% by weight;
(4) said aliphatic urethane diacrylate being present in an amount from 25% to 60% by weight;
(5) said initiator being present in an amount of 1.5 parts per hundred monomer (phm); and
(6) said at least one metal salt being present in an amount of 0.25 part per hundred monomer (phm).
15. The composition of claim 3 , wherein the thermoplastic polyurethane (TPU) being present in an amount from 0.5 to 5.0 parts per hundred monomer (phm).