Flexible hardcoat

Patent metadata

Field	Value
Publication number	US-11827802-B2
Application number	US-202017604945-A
Country	US
Kind code	B2
Filing date	May 4, 2020
Priority date	May 9, 2019
Publication date	Nov 28, 2023
Grant date	Nov 28, 2023

Abstract

A hardcoat composition includes one or more multifunctional (meth)acrylate monomers, and a nanoparticle mixture dispersed within the one or more multifunctional (meth)acrylate monomers. The nanoparticle mixture includes a first population of semi-reactive nanoparticles having an average particle diameter in a range from 5 nm to 60 nm, and a second population of non-reactive nanoparticles having an average particle diameter in a range from 5 nm to 60 nm.

First claim

What is claimed is:

1. A hardcoat composition comprising:
one or more multifunctional (meth)acrylate monomers comprising:
at least one first (meth)acrylate monomers with at least 3 (meth)acrylate groups and
alkoxy repeat units; and
at least one second multi-functional (meth)acrylate monomer that is different from the first monomer; and

a silica nanoparticle mixture dispersed within the one or more multifunctional (meth)acrylate monomers, the silica nanoparticle mixture comprising:
1 to 75 wt% of a first population of semi-reactive silica nanoparticles, the semi-reactive silica nanoparticles having a reactive functional group and a non-reactive functional group, the first population of semi-reactive silica nanoparticles have an average particle diameter in a range from 10 nm to 40 nm; and

99 to 25 wt% of a second population of non-reactive silica nanoparticles, the second population of non-reactive silica nanoparticles have an average particle diameter in a range from 10 nm to 40 nm, wherein the hardcoat composition upon curing forms a hardcoat that exhibits no visible scratch after at least 500 scratch cycles when tested for abrasion resistance using a mechanical device with a 3.0 kg weight and capable of oscillating an abrasive material adhered to a stylus across the hardcoat where the oscillation was performed perpendicular to the coating direction, and the stylus was a cylinder with a flat base and a diameter of 3.2 cm, oscillated over a 60 mm wide sweep width at a rate of 210 mm/sec (2 wipes/second), and the abrasive material was steel wool #0000 adhered to the stylus, and exhibits an average curl of less than or equal to 2.0 millimeters when tested for curl by cutting a 7.6 cm x 7.6 cm (3 inches×3 inches) sample and permitting the sample to lie flat on a table and measuring the edge lift of the 4 corners of the sample from the table surface and averaging.

2. A hardcoat composition comprising:
one or more multifunctional (meth)acrylate monomers comprising:
at least one first (meth)acrylate monomers with at least 3 (meth)acrylate groups and
alkoxy repeat units; and
at least one second multi-functional (meth)acrylate monomer that is different from the first monomer; and

a silica nanoparticle mixture dispersed within the one or more multifunctional (meth)acrylate monomers, the silica nanoparticle mixture comprising:
1 to 75 wt% of a first population of semi-reactive silica nanoparticles, the semi-reactive silica nanoparticles having a reactive functional group and a non-reactive functional group, the first population of semi-reactive silica nanoparticles have an average particle diameter in a range from 10 nm to 40 nm;
the non-reactive functional group formed by a non-reactive surface treatment with a compound having a general formula R-SiR′ m (OR″) 3-m , wherein R is methyl or ethyl, R′ is a (C 1 -C 4 )alkyl, R″ is a (C 1 -C 4 )alkyl, m is an integer from 0 to 2; and
the reactive functional group formed by a reactive surface treatment with a compound having a general formula X′-L′-SiR′ m (OR″) 3-m , wherein X′ is a free-radically polymerizable group, L′ is an (C 1 -C 12 )alkylene, R′ is a (C 1 -C 4 )alkyl, R″ is a (C 1 -C 4 )alkyl, m is an integer from 0 to 2

99 to 25 wt% of a second population of non-reactive silica nanoparticles, the second population of non-reactive silica nanoparticles have an average particle diameter in a range from 10 nm to 40 nm, the non-reactive silica nanoparticle having a non-reactive surface treatment with a compound having a general formula R-SiR′ m (OR″) 3-m , wherein R is methyl or ethyl, R′ is a (C 1 -C 4 )alkyl, R″ is a (C 1 -C 4 )alkyl, m is an integer from 0 to 2, wherein the hardcoat composition upon curing forms a hardcoat that exhibits no visible scratch after at least 500 scratch cycles when tested for abrasion resistance using a mechanical device with a 3.0 kg weight and capable of oscillating an abrasive material adhered to a stylus across the hardcoat where the oscillation was performed perpendicular to the coating direction, and the stylus was a cylinder with a flat base and a diameter of 3.2 cm, oscillated over a 60 mm wide sweep width at a rate of 210 mm/sec (2 wipes/second), and the abrasive material was steel wool #0000 adhered to the stylus, and exhibits an average curl of less than or equal to 2.0 millimeters when tested for curl by cutting a 7.6 cm x 7.6 cm (3 inches×3 inches) sample and permitting the sample to lie flat on a table and measuring the edge lift of the 4 corners of the sample from the table surface and averaging.

3. The hardcoat composition according to claim 2 , wherein the non-reactive surface treatment for the first population and second population is a compound having a formula R-SiR′ m (OR″) 3-m , wherein R is methyl, R′ is a (C 1 -C 2 )alkyl, R″ is a (C 1 -C 2 )alkyl, and m is an integer from 0 to 2.

4. The hardcoat composition according to claim 2 , wherein the non-reactive surface treatment for the first population and second population is a compound having a formula R-SiR′ m (OR″) 3-m , wherein R is methyl, m is 0, and R″ is a ethyl or methyl.

5. The hardcoat composition according to claim 2 , wherein the reactive surface treatment compound has a general formula X′-L′-SiR′ m (OR″) 3-m , wherein X′ is a (meth)acryl or vinyl group, L′ is an (C 3 )alkylene, m is 0, and R″ is a ethyl or methyl.

6. The hardcoat composition according to claim 1 , wherein the silica nanoparticle mixture comprises:
1 to 50 wt% of a first population of semi-reactive silica nanoparticles; and
99 to 50 wt% of a second population of non-reactive silica nanoparticles.

7. The hardcoat composition according to claim 1 , wherein the semi-reactive silica nanoparticles comprise:
5 to 50 mol% reactive functional groups; and
95 to 50 mol% non-reactive functional groups.

8. The hardcoat composition according to claim 1 , wherein the semi-reactive silica nanoparticles comprise:
5 to 30 mol% reactive functional groups; and
95 to 70 mol% non-reactive functional groups.

9. The hardcoat composition according to claim 1 , wherein the one or more multifunctional (meth)acrylate monomers form at least 95 wt% of monomers in the hardcoat composition, and the hardcoat composition contains less than 5 wt% urethane.

10. The hardcoat composition according to claim 1 , wherein the first population of semi-reactive silica nanoparticles have an average particle diameter that is substantially equal to the second population of non-reactive silica nanoparticles average particle diameter.

11. The hardcoat composition according to claim 1 , wherein the silica nanoparticle mixture is present in the hardcoat composition at a loading in a range from 30 to 68 wt% by weight total solids.

12. The hardcoat composition according to claim 1 , wherein the silica nanoparticle mixture is present in the hardcoat composition at a loading in a range from 40 to 60 wt% by weight total solids.

13. The hardcoat composition according to claim 1 , wherein the first population of semi-reactive silica nanoparticles has an average particle diameter in a range from 10 nm to 30 nm, and the second population of non-reactive silica nanoparticles has an average particle diameter in a range from 10 nm to 30 nm.

14. A hardcoat comprising a reaction product of the hardcoat composition of claim 1 .

15. The hardcoat according to claim 14 , wherein the hardcoat has a uniform thickness in a range from 1 to 10 micrometers.

16. A hardcoat film comprising:
a substrate; and
the hardcoat, according to claim 14 , disposed on the substrate.

17. The hardcoat film according to

Assignees

• 3M Innovative Properties Company

Inventors

• Condo Peter D
• Thompson David Scott
• Stradinger John J
• Leatherdale Catherine A
• Pokorny Richard J
• Solomonson Steven D

Classifications

• C09D133/06 Primary

  of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical · CPC title

• C09D7/67 Primary

  Particle size smaller than 100 nm · CPC title

• C09D4/00 Primary

  Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond {; Coating compositions, based on monomers of macromolecular compounds of groups C09D183/00 - C09D183/16} · CPC title

• C09D133/04

  Homopolymers or copolymers of esters {(C09D143/04 takes precedence)} · CPC title

• C08K3/36

  Silica · CPC title