Energy curable pressure-sensitive adhesive compositions
First Claim
1. A pressure-sensitive adhesive composition comprising the polymerization reaction product of starting materials consisting essentially of:
- (a) at least one free-radically polymerizable component selected from the group consisting of an acrylate, a methacrylate, and a vinyl ester;
(b) at least one polyurethane precursor component, said polyurethane precursor component comprising;
(i) a least one di- or polyisocyanate; and
(ii) at least one diol or polyol;
(c) at least one organometallic complex salt; and
(d) at least one free-radical photoinitiator selected from the group consisting of acetophenones, ketals, benzophenones, aryl gyloxylates, acylphosphine oxides and peroxides;
said reaction product being obtained by sequential exposure to visible electromagnetic radiation and then to ultraviolet electromagnetic radiation.
0 Assignments
0 Petitions
Accused Products
Abstract
The present invention provides a pressure-sensitive adhesive composition and a method for producing the same. The pressure-sensitive adhesive composition is produced by the combination of at least one free-radically photopolymerizable monomer and at least one set of polyurethane precursors, and a suitable photoinitiation system consisting of at least one salt of a cationic organometallic complex, an additional free-radical photo initiator and the application of sufficient energy to photopolymerize same by sequential exposure to visible electromagnetic radiation and then to ultraviolet electromagnetic radiation.
108 Citations
19 Claims
-
1. A pressure-sensitive adhesive composition comprising the polymerization reaction product of starting materials consisting essentially of:
-
(a) at least one free-radically polymerizable component selected from the group consisting of an acrylate, a methacrylate, and a vinyl ester; (b) at least one polyurethane precursor component, said polyurethane precursor component comprising;
(i) a least one di- or polyisocyanate; and
(ii) at least one diol or polyol;(c) at least one organometallic complex salt; and (d) at least one free-radical photoinitiator selected from the group consisting of acetophenones, ketals, benzophenones, aryl gyloxylates, acylphosphine oxides and peroxides; said reaction product being obtained by sequential exposure to visible electromagnetic radiation and then to ultraviolet electromagnetic radiation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18)
-
3. The composition according to claim 1 wherein said free-radically polymerizable component is an alkyl acrylate or alkyl methacrylate wherein said alkyl group contains from about 4 to about 14 carbon atoms.
-
4. The composition according to claim 1 wherein the ratio of the isocyanate groups to hydroxyl groups present in said polyurethane precursor component is in the range of from about 1:
- 2 to 2;
1.
- 2 to 2;
-
5. The composition according to claim 1 wherein the ratio of the isocyanate groups to hydroxyl groups in said polyurethane precursor component is in the range of from about 1:
- 1.25 to 1.25;
1.
- 1.25 to 1.25;
- 6. The composition according to claim 1 wherein said organometallic complex salt has the following structure
- space="preserve" listing-type="equation">[(L.sup.5)(L.sup.6)M].sup.+e X.sub.f
wherein; M represents a metal atom selected from the group consisting of elements of the Periodic Groups IVB, VB, VIIB, and VIII; L5 represents from zero to three pi-electron contributing ligands that can be the same or different ligand selected from the group consisting of;
substituted and unsubstituted acylic and cyclic unsaturated compounds and groups, and substituted and unsubstituted carbocyclic aromatic and heterocyclic aromatic compounds, each capable of contributing two to twelve pi-electrons to the valence shell of M;L6 represents from zero to 6 ligands that can be the same or different, contributing an even number of sigma-electrons, selected from the group consisting of;
mono-, di-, and tri-dentate ligands, each donating 2, 4, or 6 sigma-electrons to the valence shell of M;
the total electronic charge contributed to M by L5 and L6 plus the ionic charge on M results in a residual net positive charge of e to the complex;e is an integer having a value of 1 or 2, the residual electrical charge of the cation; X is an anion selected from the group consisting of;
organic sulfonate anions and halogen-containing complex anions of a metal or metalloid; andf is an integer selected from 1 or 2, the number of anions required to neutralize the positive charge e on the cation.
-
-
7. The composition according to claim 1 wherein the organometallic complex salt has the following structure:
-
space="preserve" listing-type="equation">[(L.sup.5)M].sup.+3 X.sub.fwherein; L5 represents pi-electron contributing ligands that can be the same or different selected from the group consisting of;
substituted and unsubstituted acyclic and cyclic unsaturated compounds and groups; and
substituted and unsubstituted carbocyclic aromatic and heterocyclic aromatic compounds, each capable of contributing two to twelve pi-electrons to the valence shell of M;
with the proviso that the total electronic charge contributed to M by L5 plus the ionic charge on M results in a residual net positive charge of e to the complex;e is an integer having a value of 1 or 2, the residual electrical charge of the cation; X is an anion selected from organic sulfonate anions and halogen-containing complex anions of a metal or metalloid; and f is an integer selected from 1 or 2, the number of anions required to neutralize the positive charge e on the cation.
-
-
8. The composition according to claim 1 wherein said starting materials further comprise polar monomer copolymerizable with said at least one free-radically polymerizable component.
-
9. The composition according to claim 1 wherein said free-radically polymerizable component is partially polymerized to a syrup having a viscosity of from about 300 to 20,000 centipoise at room temperature.
-
10. The composition according to claim 1 wherein said polyisocyanate is an aliphatic polyisocyanate and said polyol is a hydroxy alkylated bisphenol.
-
11. The composition according to claim 1 comprising the polymerization reaction product of starting materials comprising:
-
(a) from about 60 to about 95 parts of said acrylate; (b) from about 5 parts to about 40 parts of said at least one polyurethane precursor component comprising;
(1) an hydroxy alkylated bisphenol selected from the group consisting of;
hydroxyethylated bisphenol-A, and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene; and
(2) at least one aliphatic polyisocyanate selected from the group consisting of;
hexamethylene diisocyanate, the isocyanurate and the biuret thereof, and 4,4'"'"'-methylenebis(cyclohexylisocyanate);(c) from about 0.01 part to about 10 parts of said organometallic complex salt, and (d) from about 0.01 to about 10 parts of said free-radical photoinitiator.
-
-
12. The composition according to claim 1 comprising the polymerization reaction product of starting materials comprising
(a) from about 70 parts to 80 parts of isooctyl acrylate; -
(b) from about 20 parts to about 30 parts of at least one hydroxy alkylated bisphenol selected from the group consisting of;
hydroxyethylated bisphenol-A, and 9,9-bis[4-(2-hydroxy ethoxy)phenyl]fluroene; and
at least one aliphatic polyisocyanate selected from the group consisting of;
hexamethylene diisocyanate, the isocyanurate and the biuret thereof, and 4,4'"'"'-methylenebis(cyclohexylisocyanate),(c) from about 0.01 part to about 10 parts of (eta5 -cyclopentadienyl)(eta6 -xylene)iron(+1)hexafluorophosphate, (d) from about 0.01 to about 10 parts of 2,2-dimethoxy-2-phenylacetophenone; and (e) from 0 to about 1 part 1,6-hexanediol diacrylate.
-
-
13. The composition according to claim 12 wherein said starting materials further comprise from about 2 to about 5 parts of a bifunctional monomer.
-
14. The composition according to claim 12 further comprising a polar monomer copolymerizable with said acrylate.
-
15. The composition according to claim 14 wherein said polar monomer copolymerizable with said acrylate is selected from strongly polar and moderately polar monomers.
-
16. The composition according to claim 1 wherein said starting materials further comprise at least one adjuvant selected from the group consisting of:
- hydrophobic silica, glass microspheres, polymeric microspheres, and pigments.
-
18. A pressure-sensitive adhesive tape comprising at least one layer of the pressure-sensitive adhesive composition of claim 1 and a backing therefor.
-
17. A pressure-sensitive adhesive composition comprising the polymerization reaction product of starting materials consisting essentially of:
-
(a) at least one free-radically polymerizable component selected from the group consisting of an acrylate, a methacrylate, and a vinyl ester; (b) at least one polyurethane precursor component, said polyurethane precursor component comprising;
(i) at least one di- or polyisocyanate; and
(ii) at least one diol or polyol;(c) at least one organometallic complex salt; and (d) at least one free-radical photoinitiator selected from the group consisting of acetophenones, ketals, benzophenones, aryl gyloxylates, acylphonsphine oxides and peroxides; the ratio of the total weight of said free-radically polymerizable component to the total weight of said polyurethane precursor component being from about 70;
30 to about 90;
10;
said reaction product being obtained by sequential exposure to visible electromagnetic radiation and then to ultraviolet electromagnetic radiation.
-
-
19. A process for making a pressure-sensitive adhesive comprising the steps of:
-
(a) providing a composition comprising; (i) at least one free-radically polymerizable component selected from the group consisting of an acrylate, a methacrylate and a vinyl ester; (ii) at least one polyurethane precursor component, said polyurethane component comprising at least one di- or polyisocyanate and at least one diol or polyol; (iii) at least one organometallic complex salt; and (iv) at least one free-radical photoinitiator;
said composition being substantially free of an onium salt;(b) exposing said composition to a sufficient amount of visible electromagnetic radiation to activate said organometallic complex salt; and (c) thereafter exposing the photoreaction product obtained in step (b) to ultraviolet electromagnetic radiation to activate said free-radical photoinitiator; wherein said process provides a pressure-sensitive adhesive.
-
Specification