WO2025229596A1

WO2025229596A1 - Articles comprising hardcoat composition comprising alkoxy silane and silica nanoparticles, and methods

Info

Publication number: WO2025229596A1
Application number: PCT/IB2025/054587
Authority: WO
Inventors: Xi Chen; Naiyong Jing
Original assignee: 3M Innovative Properties Co
Current assignee: 3M Innovative Properties Co
Priority date: 2024-05-02
Filing date: 2025-05-01
Publication date: 2025-11-06
Anticipated expiration: 2026-11-02

Abstract

An article is described comprising A) a substrate; B) a hardcoat layer disposed on the substrate wherein the hardcoat layer comprises the hydrolyzed and condensed reaction product of a composition comprising: i) first silane monomer(s) having the formula R1Si(OR)3 wherein R and R1 is methyl or ethyl; ii) silica nanoparticles having a primary average particle size of 10 to 40 nm in an amount greater than 30 wt.%; and C) a surface layer comprising a hydrophilic silane disposed on the hardcoat layer. Also described are methods of use.

Description

ARTICLES COMPRISING HARDCOAT COMPOSITION COMPRISING ALKOXY SILANE AND SILICA NANOPARTICLES, AND METHODS

Summary

In one embodiment, an article is described comprising:

A) a substrate;

B) a hardcoat layer disposed on the substrate wherein the hardcoat layer comprises the hydrolyzed and condensed reaction product of a composition comprising: i) first silane monomer(s) having the formula R¹Si(OR)3 wherein R and R¹ is methyl or ethyl; ii) silica nanoparticles having a primary average particle size of 10 to 40 nm in an amount greater than 30 wt.%; and

C) a surface layer comprising a hydrophilic silane disposed on the hardcoat layer.

Also described are methods of use. In one embodiment, the method of using an article comprises providing an article as described herein; writing on the hardcoat layer or surface layer; and removing the writing.

The hardcoat described herein can contribute to improved properties. For example, in one embodiment, the hardcoat has improved flexibility.

Brief Description of the Drawings

FIG. 1 is a cross-section schematic of an illustrative article comprising a hydrolyzed and condensed hardcoat layer disposed on a substrate, a surface layer comprising a hydrophilic silane disposed on the hardcoat layer, and other optional layers;

FIG. 2 is a cross-section schematic of an illustrative article comprising a hydrolyzed and condensed hardcoat layer and a surface layer comprising a hydrophilic silane disposed on both sides of a substrate; FIG. 3 is a cross-section schematic of an illustrative article comprising a hydrolyzed and condensed hardcoat layer disposed on a substrate;

FIG. 4 is a flowchart utilized to implement various embodiments herein; and

FIG. 5 is a block diagram of computing hardware utilized to implement various embodiments herein.

Detailed Description of Illustrative Embodiments

In one embodiment, a hardcoat coating composition is described. The hardcoat coating composition comprises first silane monomer(s) having the formula R¹Si(OR)3 wherein R and R¹ is methyl or ethyl. Thus, the first silane monomer is methyltrimethoxysilane, ethyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxy silane, and combination thereof. In some embodiments, the first silane monomer is methyltrimethoxysilane, methyltriethoxysilane, or a combination thereof. In some embodiments, the first silane monomer is methyltriethoxysilane. The categorization of an alkoxy silane monomer as hydrophobic or hydrophilic is typically made on the basis of the R¹ group. Alkoxy silane monomers wherein R¹ is alkyl are considered hydrophobic. In some embodiments, the hardcoat coating composition comprises at least 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, or 75 wt.% of first silane monomer(s).

In some embodiments, the hardcoat composition comprises first silane monomer(s) as just described and a second silane monomer(s) having the formula (R²)4-mSi(OR)_m or Si(OR)4, wherein R and R² are organic groups with the proviso that R² is not methyl or ethyl and m is 1, 2 or 3 and more typically is 2 or 3.

Thus, the second silane monomers are different silane monomer than the first silane monomers. In some embodiments, the second silane monomers are also hydrophobic, such as in the case when R² is a hydrocarbon group having at least 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 carbon atoms. In some embodiments, R² is no greater than 30, 28, 26, 24, 22, or 20 carbon atoms. The R² may be a straight-chain, branched, or cyclic. Typically, R² is aliphatic such as in the case of alkyl, alkenyl, alkynyl. The aliphatic group may optionally comprise heteroatoms (e.g. oxygen, nitrogen, or sulfur). Alternatively, R² may comprise an aromatic group.

Representative second monomers include for example propyltrimethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, pentyltrimethoxysilane, pentyltriethoxysilane, heptyltrimethoxysilane, heptyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane dimethyldimethoxysilane and dimethyldiethoxysilane.

In some embodiments, the second monomer is (R²)4-mSi(OR)_m wherein R and m are as previously described and R² comprises a group that reacts with hydroxyl, such as an epoxy silane. Suitable epoxy silanes for use herein include, but are not limited to, 2-(3,4-epoxy cyclohexyl) ethyltrimethoxysilane; 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane; (3-glycidoxypropyl) trimethoxysilane; (3-glycidoxypropyl) triethoxysilane; and mixtures thereof.

In some embodiment, the second monomer is Si(OR)4, a tetraalkoxysilanes, such as tetraethylorthosilicate (“TEOS”), and oligomeric forms of tetraalkoxy silane.

When second monomer(s) are present, the weight ratio of first silane monomer(s) to second silane monomer(s) is at least 4: 1. In typical embodiments, the weight ratio of first silane monomer(s) to second silane monomer(s) is at least 5: 1, 6:1, 7: 1, 8:1, or 9: 1. In other words, the first silane monomer(s) are at least 80, 81, 82, 83, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100 wt.% of the sum of the first silane monomer(s) and second silane monomer(s). Thus, the second silane monomer(s) are no greater than 20 wt.% of the sum of the first silane monomer(s) and second silane monomer(s). In some embodiments, the total amount of second silane monomer(s) is no greater than 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 wt.% of the sum of the first silane monomer(s) and second silane monomer(s).

During hydrolysis, the alkoxy OR groups of the alkoxysilane reacts with water forming ROH (e.g. methanol or ethanol). Upon removal of the OR group during hydrolysis, the OR groups of the silane monomer(s) form OH groups. In an acidic solution, the resulting silanol group undergoes a condensation reaction with other silanols or the silanol groups on silica particles by losing water, thus forming a polysiloxane network. When the optional organic polymer comprises functional groups such as alkoxy silane or hydroxyl, the organic polymer can also readily condense and be incorporated into the polysiloxane network.

The hydrolyzed and condensed polysiloxane network comprises a lower amount of siloxane moieties as compared to the amount of first silane monomer(s) of the hardcoat composition. For example, methyltriethoxy (MTES) silane has an atomic weight of 164 g/mole. However, if all the ethoxy groups are hydrolyzed off to ethanol, the 100% condensed methyltriethoxy can be represented by MeSiC>3/2 , having an atomic weight of 67 g/mole. Thus, the MTES can lose over half it’s mass during the reaction. Hence, when the hardcoat coating solution comprises 70 wt.% first silane monomers and 30 wt.% silica nanoparticles and 100% of the OR groups of the first silane monomers are hydrolyzed and condensed, the resulting poly siloxane can network comprise half the amount of siloxane moieties derived from the first silane monomer (i.e. 35 wt.%) with the 30 wt.% of silica nanoparticles. Thus, the amount of silica nanoparticles in the polysiloxane network can be 30/65 X 100% = 46%. This is under the assumption that all the silanol groups have bee converted to Si-O-Si.

In some embodiments, the hydrolyzed and condensed reaction product (i.e. polysiloxane network) has a R¹ carbon concentration of less than the calculated amount of the same composition comprising 70 wt.% first silane monomer(s). In some embodiments, the polysiloxane network comprises two components, i.e. MeSiCha (Mw =67) and SiO2 (Mw=60). When the hardcoat coating solution comprises 70 wt.% of MeSi(OEt)3 and 30 wt.% nanoparticles, the amount of carbon can be calculated from the following formula: 12X0.7/(67X0.7 + 60X0.3) = 12.9%. Thus, when the hardcoat coating solution comprises MTES and greater than 30 wt.% nanoparticle, the amount of carbon is less than 12.9 wt.%. For example, when the hardcoat coating solution comprises 50 wt.% of MeSi(OEt)3 and 50 wt.% nanoparticles, the amount of carbon can be calculated from the following formula: 12X0.5/(67X0.5 + 60X0.5) = 9.4%.

As yet another example, when the hardcoat coating solution comprises 70 wt.% of EtSi(0Et)3 and 30 wt.% nanoparticles, the amount of carbon can be calculated from the following formula: 24 X 0.7/(67 X 0.7 + 60 X 0.3) = 25.8%. Thus, when the hardcoat coating solution comprises ETES and greater than 30 wt.% nanoparticle, the amount of carbon is less than 25.8 wt.%. For example, when the hardcoat coating solution comprises 50 wt.% of EtSi(0Et)3 and 50 wt.% nanoparticles, the amount of carbon can be calculated from the following formula: 24 X 0.5/(67 X 0.5 + 60 X 0.5) = 18.9%. The amount of carbon for various mixtures of first silane monomer(s) can be calculated in the same manner. The amount of carbon for various mixtures of first silane monomer(s) and second silane monomer(s) can also be calculated in the same manner. The amount of C of the R1 or R2 groups of the silane monomers of the hydrolyzed and condensed hardcoat can also be determined by elemental analysis such as solid state Nuclear Magnetic Resonance and/or X-ray photoelectron spectroscopy (XPS), also known as electron spectroscopy for chemical analysis (ESCA). The hardcoat composition comprises silica nanoparticles. The inclusion of the silica nanoparticles can improve the durability and increase the pencil hardness relative to the same hardcoat without silica nanoparticles. The silica nanoparticles have a primary average particle size of 10 to 40 nm. The term “primary particle size” refers to the average size of unagglomerated single particles of silica. The average particle size may be determined using transmission electron microscopy. The silica particles may be spherical or non-spherical and are typically discreet particles, rather than aggregates.

The silica particles typically have narrow particle size distributions, that is, a poly dispersity (i.e., particle size distribution) of 2.0 or less, preferably 1.5 or less. If desired, larger silica particles may be added, provided that the presence of the larger particles does not decrease the coatability of the hardcoat composition or decrease the hardcoat coating composition stability.

In some embodiments, the silica nanoparticles are not surface modified. Smaller nanoparticles, those having an average particle size of less than 20, 15, or 10 nanometers can be utilized to prepare hardcoat composition having good stability and durability without being surface modified. Larger silica nanoparticles, i.e. 30 nm or greater preferably comprise a surface treatment.

In some embodiments, the silica nanoparticles are surface modified with the first or second silane monomer as previously described. In some embodiments, the surface treatment comprises the second monomer wherein R comprises an epoxy group. In other embodiments, the surface treatment comprises the second monomer with R comprises an amine group, as described in WO2015/088808; incorporated herein by reference.

The amount of silica may be at least 10, 15, 20, 25, 30, 35, 40, 45, or 50 wt.% (solids) of the aqueous hardcoat solution or the hydrolyzed and condensed hardcoat. In some embodiments, the amount of silica is no greater than 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, or 15 wt.%. When the silica nanoparticles have an average primary particle size of about 25 nm, the amount of silica is typically no greater than 50 wt.%. When the silica nanoparticles have an average primary particle size of greater than 25 nm, the amount of silica nanoparticles may be greater than 50 wt.%.

In some embodiments, the hardcoat composition may comprise more silica nanoparticles than first silane monomer(s) (i.e. having the formula R¹ Si(OR)s wherein R and R¹ is methyl or ethyl). In this embodiment, the weight ratio of first silane monomer(s) to silica nanoparticles may be at least 1:2, 1:1.5, 1 : 1.25, or approaching 1:1. In other embodiments, the hardcoat composition may comprise the same amount or more first silane monomer(s) than nanoparticles. In some embodiments, the weight ratio of first silane monomer(s) to silica nanoparticles may be at least 1 : 1 or 2 : 1.

In some embodiments, the hardcoat further comprises at least one organic polymer comprising functional groups. The functional groups react with the hydrolyzed OR groups of the silane monomer(s). In some embodiments, the functional groups of the organic polymer are alkoxy silane or hydroxyl. The hardcoat may comprise a single polymer with one type of functional group, a single polymer with two types of functional groups, or two or more different organic polymers with the same or different functional groups. The organic polymer with functional groups typically has a weight or number average molecular weight of at least 500, 1000, 2000, 3000, 4000 or 5000 Da. In some embodiments, the organic polymer with functional groups typically has a weight or number average molecular weight of at least 10,000; 15,000, or 20,000 Da. In some embodiments, the weight or number average molecular weight is at least 30,000 or 35,000 Da. In some embodiments, the weight or number average molecular weight is no greater than 75,000 or 50,000 Da. In some embodiments, the weight or number average molecular weight is no greater than 40,000; 35,000; 30,000; 25.000; 20,000; 15,000, 10,000, or 5,000 Da. The molecular weight is typically determined by Gel Permeation Chromatograph using a suitable standard.

In some embodiments, the organic polymer is an alkoxysilane terminated polymer. The alkoxysilane terminated polymer typically comprises at least one, two, or three alkoxy silane groups.

The alkoxy terminated polymer may be represented by the formula: wherein R¹ is independently CH₃ or CH2CH3,

R³ is independently CH₃, CH₂CH₃, OCH₃, or OCH₂CH₃,

L is a covalent bond or divalent liking group, and n is 1, 2, 3, or 4.

When n is 2, the alkoxy terminated polymer may be represented by the formula

OR¹ >

R²Q-Si-L— | Polymer |— L

R³ wherein R¹, R³ and L are the same as previously described.

The divalent linking group typically has a molecular weight less than 100 or 50 g/mole. The divalent linking group may comprise moieties such as urethane, alkylene, ester, ether, amide, etc. and combinations thereof.

Various alkoxysilane terminated polymers are commercially available from Evonik and Wacker Chemie. In some embodiments, the organic polymer of the alkoxysilane terminated polymer is a polyester or polyether (e.g. polypropylene glycol) polymer. In another embodiment, the alkoxysilane terminated polymer is a polyamide polymer. For example, poly(N-isopropylacrylamide) triethoxysilane is available from Specific polymer of France. In another embodiment, the organic polymer of the alkoxysilane terminated polymer is a polyurethane, such as available as the trad designation W Pur VP Si product numbers 1021, 4021, 2031, and 4011 from Worlee-Chemie of Hamburg, Germany. In another embodiment, the alkoxysilane terminated polymer is a poly(meth)acrylate polymer, such as described in WO2015023372; incorporated herein by reference. In another embodiment, the alkoxysilane terminated polymer is a polycarbonate polymer, such as described in KR101998119; incorporated herein by reference.

In some embodiment, the organic polymer of the alkoxy silane terminated polymer has a higher glass transition temperature than polypropylene glycol polymer (e.g. greater than -25°C). Notably, alkoxysilane terminated polymer comprising a polyester polymer provided better abrasion resistance than alkoxysilane terminated polymers comprising a polypropylene glycol polymer.

In some embodiments, the alkoxysilane terminated polymer is a liquid at 25°C. The viscosity of the alkoxysilane terminated polymer may range from 100 or 150 mPas to 60,000 mPas at 25°C. In some embodiments, the viscosity at 25°C of the alkoxysilane terminated polymer is at least 250, 500, 1000, or 1500 mPas. In some embodiments, the viscosity at 25°C of the alkoxysilane terminated polymer is no greater than 50,000; 45,000; 40,000; 35,000; 30,000; 25,000; 20,000; 15,000; 10,000; 5,000; 4,000; 3,000; 2,000 or 1,000 mPas at 25°C. When the viscosity is greater than 35,000 at 25°C, the alkoxysilane terminated polymer may further comprise plasticizer. It is appreciated that viscosity is indicative of molecular weight.

In some embodiments, the organic polymer comprising functional groups is a (meth)acrylic copolymer having hydroxyl groups. The organic polymer comprising functional groups typically comprises polymerized units of a C1-C4 alkyl (meth)acrylate and a polar monomer such as a C1-C4 hydroxy-functional alkyl (meth)acrylate such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate.

In some embodiments, the(meth)acrylic copolymer has a hydroxyl number of at least 50, 75, 100, or 125 mg KOH/g of copolymer. An example of such is trade designation ELVACITE 4112. In some embodiments, the (meth)acrylic copolymer has a sufficient amount of polymerized polar monomer such that the (meth)acrylic copolymer is water dispersible or water soluble. When the amount of hydroxyl is too low, the (meth)acrylic copolymer is incompatible (opaque) with the hydrolyzed and condensed silane monomers.

In some embodiments, the hardcoat composition comprises at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 wt.% of organic polymer comprising functional groups, based on the total solids of the hardcoat (i.e. excluding water and solvent). In some embodiments, the hardcoat composition comprises no greater than 20, 15, or 10 wt.% of organic polymer comprising functional groups.

As evident from the examples, inclusion of the organic polymer comprising functional groups can increase the flexibility. In some embodiments, the “full construction” article comprising an organic polymer film substrate, a hydrolyzed and condensed hardcoat layer, and hydrophilic coating has a mandrel bend equal to or less than 3/4 inch (19.1 mm), 1/2 inch (12.7 mm), 1/4 inch (6.35 mm) , or 1/8 inch (3.18 mm) without cracking. The organic polymer film substrate comprising the hydrolyzed and condensed hardcoat layer without the hydrophilic coating and the hydrolyzed and condensed hardcoat alone has a mandrel bend less than or equal to the full construction.

The method of making the hardcoat coating composition generally comprises i) combining the previously described first hydrophobic silane monomer(s) and optional second silane monomer(s) in an aqueous solution; ii) adding acidified silica nanoparticles to the aqueous solution; iii) hydrolyzing and condensing thereby forming a poly siloxane continuous network. In some embodiments, steps iii) and occur prior to step ii). The organic polymer comprising silane groups, hydroxyl groups, or acid groups is than added, typically as an aqueous solution. The hardcoat coating composition also typically comprises surfactant.

The aqueous solution comprises water and preferably a high boiling point organic solvent, such as 1 -methoxy -2 -propanol. The boiling point of the solvent is typically at least 80, 90, 100, 110, or 120°C. In the absence such solvent the cured coating surface is non-uniform, typically being uneven in thickness and exhibiting other coating defects.

In some embodiments, non-aqueous silica sols (also called silica organosols), wherein the liquid phase is predominantly organic solvent, may be used in the method of making the hardcoat composition. However, in typical embodiments, the silica nanoparticles utilized in the method are dispersions of submicron size silica nanoparticles in an aqueous liquid phase optionally comprising organic solvent mixture. Inorganic silica sols in aqueous media are well known in the art and commercially available. Silica sols in water or water-alcohol solutions are available commercially under such trade names NALCO from Nalco Water, Naperville, IL. Commercially available silica nanoparticles suitable for use in the present invention include NALCO™ 1115, NALCO™ 2326, NALCO™ 2327, and NALCO™ 2329.

In some embodiments, the hardcoat composition comprises silica having a mean particle size of 8 nanometers. This can be accomplished by utilizing NALCO™ 1130. In other embodiments, the hardcoat composition comprises silica having a mean particle size of 20 nanometers. This can be accomplished by utilizing NALCO™ 1130 NALCO™ 2327. In some embodiments, the hardcoat composition comprises a combination of a first silica and second silica wherein the first silica has a larger particle size than the second silica. For example, the first silica may have a mean particle size of 8 nanometers and the second silica may have a mean particle size of 20 nm. The weight ratio of the first (smaller) silica to the second (larger) silica may range from 10: 1 to 1 : 10. In some embodiments, the weight ratio of the first (smaller) silica to the second (larger) silica may be at least 2:10, 3: 10, 4:10, 5:10, 6: 10, 7:10, 8: 10, 9:10, or 10:10 (in other words 1: 1). In some embodiments, the weight ratio of the first (smaller) silica to the second (larger) silica is no greater than 10:2, 10:3, 10:4, 10:5, 10:6, 10:7, 10:8, 10:9 or 10: 10 (in other words 1: 1).

The hardcoat coating composition generally contains sufficient acid to provide a pH of less than 6 or 5. In some embodiments, it has been found that the pH of the coating composition can be adjusted to pH from 5 to 6 after reducing the pH to less than 5. This allows one to coat pH-sensitive substrates. Sodium stabilized silica nanoparticles are typically first acidified prior to dilution with an organic solvent such as ethanol. Dilution prior to acidification may yield poor or non-uniform coatings. Ammonium stabilized silica nanoparticles may generally be diluted and acidified in any order.

The hardcoat coating composition typically contains a (e.g. weaker) acid having a pKa of >4, such as acetic acid. In other embodiments, the hardcoat coating composition typically contains a (e.g. weaker) acid having a pKa of >4 in combination with a stronger acid having a pKa (H2O) of <3.5 , <2.5 , or less than 1. Useful acids include both organic and inorganic acids and may be exemplified by oxalic acid, citric acid, H₂SO₃, H3PO4, CF3CO2H, HC1, HBr, HI, HBrO₃, HNO₃, HC1O₄, H₂SO₄, CH3SO3H, CF3SO3H, CF3CO2H, and CH3SO2OH. A mixture of organic and inorganic acid can be utilized. In some embodiments, the weight ratio of stronger acid (e.g. nitric acid) to weaker acid (e.g. acetic acid) is less than 5:1, 4: 1, 3: 1, 2: 1, or 1: 1.

The acidified silica nanoparticle hardcoat coating compositions can be coated directly onto hydrophobic organic and inorganic substrates without either organic solvents or surfactants. The wetting property of these inorganic nanoparticle aqueous dispersions on hydrophobic surfaces such as polyethylene terephthalate (“PET”) or polycarbonate (“PC”) is a function of the pH of the dispersions and the pKa of the acid. Hardcoat coating compositions typically bead up (i.e. dewet) on the organic substrates at neutral or basic pH.

The hydrolyzed and condensed hardcoat composition typically comprises silica nanoparticles dispersed in a continuous gelled poly siloxane network. As used herein, the term “continuous” refers to covering the surface of the substrate with virtually no discontinuities or gaps in the areas where the hydrolyzed and condensed hardcoat composition was applied.

In order to uniformly coat a hardcoat composition onto a (e.g. hydrophobic) substrate from an aqueous system it may be desirable to increase the surface energy of the substrate and/or reduce the surface tension of the coating composition. The surface energy may be increased by oxidizing the substrate surface prior to coating using corona discharge, actinic radiation, or flame treatment methods. These methods can contribute to bonding of the hydrophilic silane coating to the hardcoat. Other methods capable of increasing the surface energy of the article include the use of organic polymeric primers such as thin coatings of polyvinylidene chloride (PVDC). Alternatively, the surface tension of the coating composition may be decreased by addition of lower alcohols (Ci to Cs).

In some embodiments, it may be beneficial to add a wetting agent, such as a surfactant, to the hardcoat composition. The term “surfactant” as used herein describes molecules comprising hydrophilic (polar) and hydrophobic (non-polar) regions on the same molecule which are capable of reducing the surface tension of the coating solution. Useful surfactants include anionic surfactant, cationic surfactants, and non-ionic surfactant such as those described in US Patent No. 6,040,053 (Scholz et al.) and US 10,316,212 (Jing et al.) incorporated herein by reference; as well as silicone surfactants, such as commercially available as the trade designations BYK-3500 from BYK and DOWSIL™ Q2-5211, a silicone poly ether copolymer available from Dow.

In some embodiments, a surfactant is included in the hardcoat coating composition at a concentration of at least 0.25, 0.5, 1, 1.5 or 2 wt.% of the aqueous hardcoat coating composition. The amount of surfactant is typically no greater than 5, 4, 3, 2, or 1 wt.%. of the aqueous hardcoat coating composition.

Other useful wetting agents include poly ethoxylated alkyl alcohols (e.g., BRU™ 30 and BRU™ 35 from ICI Americas, Inc., and TERGITOL™ TMN-6™ Specialty Surfactant from Union Carbide Chemical and Plastics Co., polyethoxylated alkylphenols (e.g., TRITON™ X-100 from Union Carbide Chemical and Plastics Co., ICONOL™ NP-70 from BASF Corp.) and polyethylene glycol/polypropylene glycol block copolymer (e.g., TETRONIC™ 1502 Block Copolymer Surfactant, TETRONIC™ 908 Block Copolymer Surfactant, and PLURONIC™ F38 Block Copolymer Surfactant all from BASF, Corp.). When present, such wetting agent(s) are used in amounts of less than 0.1 percent by weight of the coating composition, preferably 0.003 to 0.05 percent by weight of the coating composition depending on the amount of silica nanoparticles. Rinsing or steeping the coated article in water may be desirable to remove excess surfactant or wetting agent.

The hardcoat layer alone or in combination with the surface layer comprising a hydrophilic silane may have a gloss or matte surface. Matte surfaces typically have lower transmission and higher haze values than gloss surfaces. For examples the haze is generally at least 5%, 6%, 7%, 8%, 9%, or 10% as measured according to ASTM D1003. Whereas gloss surfaces typically have a gloss of at least 90 or 95 as measured according to ASTM D 2457-03 at 60 or 80 degrees; matte surfaces have a gloss of less than 85, 80, 70, 65, 60, 55, 50, 45, or 40. In some embodiments the gloss of the matte surface is at least 20 or 30.

Matte surfaces can conceal defects such as scratches and contaminations such as dirt, stains, fingerprints. Another benefit of having the matte surfaces is that they are more visually attractive. Further, the subtle touch and friction of matte surfaces creates a feeling of writing on conventional paper.

The hard coat layer alone or in combination with the surface layer can be rendered matte using various known techniques. In some embodiments, the surface can be roughened or textured to provide a matte surface by embossing the surface with a suitable tool that has been bead-blasted or otherwise roughened, as well as by curing the composition against a suitable roughened master or removable liner.

In other embodiments, the hard coat composition may comprise a suitably sized inorganic or organic matte particles such as silica, glass beads, or organic polymeric beads such as polyethylene (PE), polystyrene (PS), or polymethylmethacrylate (PMMA). In some embodiments, the organic polymeric beads have a density of about 1 g/cm³. (e.g. =+/- 0.1 g/cm³). Such matte particles typically have an average particle size ranging from about 1 to 10 microns. The amount of matte particles may be at least 4 or 5 wt.% and typically no greater than 15 or 10 wt.%

In some embodiments, the average particle size of the matte particles is less than 2X, 1.9X, 1.8X, 1.7X, 1.6X, 1.5X, 1.4X, 1.3X, 1.2X, 1.1X, or IX (in other word about equal) to the average thickness of the dried and cured hardcoat.

In one embodiment, the average size of the matte particles is at least 6 or 7 microns and the concentration may range from 4-7 wt.%. In another embodiment, two different sized matte particle may be used. For example, first matte particles having an average size of 6 or 7 microns may be combined with second matte particles having an average size of 5 microns. The amount of first matte particles may be at least 1, 1.5, or 2 wt.% and no greater than 5 or 4 wt.%. The amount of second matte particles may be at least 2, 2.5, or 3 wt.% and no greater than 8 or 7 wt.%. The kinds and amount of matte particles are typically selected to provide good or excellent writability and lower gloss values. The 60 or 80 degree gloss may be less than 10, 9, 8, 7, 6, 5, or 4,

The aqueous hardcoat coating compositions described herein and illustrated by the examples are shelf stable for 3 months at room temperature (25C) or 1 month at 50°C. The aqueous hardcoat coating compositions do not gel, opacify, or otherwise deteriorate significantly.

Hardcoat coating compositions are preferably coated on the article using conventional techniques, such as bar, roll, curtain, rotogravure, spray, or dip coating techniques. In order to ensure uniform coating and wetting of the film, it may be desirable to oxidize the substrate surface prior to coating or increase the surface energy by applying a primer, as previously described. The aqueous hardcoat coating compositions are applied in uniform average thicknesses varying by less than 20 nm and more preferably by less than 10 nm in order to avoid visible interference color variations in the coating.

The hydrolyzed and condensed hardcoat composition typically has an average thickness of at least 1, 2, 3, 4 or 5 microns ranging up to 10 microns. More typically, the thickness of the hydrolyzed and condensed hardcoat composition is no greater than 9, 8, 7, 6, or 5 microns. The abrasion properties of the hardcoat can improve as thickness is increased. However, the flexibility of the hardcoat can also decrease as the thickness increases. The hardcoat thickness can be measured with an ellipsometer such as a Gaertner Scientific Corp. Model No. L115C Ellipsometer.

Hardcoat coatings can be coated on both sides of a substrate if desired. Alternatively (not shown), the hardcoat coatings may be coated on one side of the substrate, as depicted in FIG. 1.

Once coated, the coat substrate is typically dried and thermally cured at temperatures of 90 °C to 150°C in a recirculating oven. An inert gas may be circulated. The temperature may be increased further to speed the drying process, depending on the substrate.

The hardcoat coating composition itself provides a tough, abrasion resistant layer that protects the substrate from damage from causes such as scratches, abrasion and solvents. Although the hydrolyzed and condensed hardcoat composition alone can provide a rewritable or anti-fog surface, in favored embodiments a surface layer comprising a hydrophilic silane is disposed on the hydrolyzed and condensed hardcoat composition. Advantageously, permanent marker writing and ghosting from dry erase markers is more easily removable with water from the surface layer comprising a hydrophilic silane.

The hydrophilic silane surface layer can be applied in a monolayer thickness and can be as thick as 10 microns. The hydrophilic silane surface layer typically has a thickness no greater 9, 8, 7, 6, 5, 4, 3, 2, or 1 micron. In some embodiments, the hydrophilic silane surface layer has a thickness of at least 50, 75 or 100 nm and no greater than 750, 500, or 250 nm.

The vast majority of the -OH groups formed during hydrolysis are crosslinked with the acid of the hardcoat coating composition. However, the cured hardcoat layer can comprise some -OH groups at the surface that can covalently bond with the hydrophilic silane of the surface layer forming siloxane (Si-O-Si) bonds.

In some embodiment, the hydrophilic silane of the surface layer comprises a non-zwitterionic sulfonate-organosilanol compound. Examples include non-zwitterionic sulfonate-organosilanol compounds such as those disclosed in US Patent Nos. 4,152,165 (Langager et al.) and 4,338,377 (Beck et al.).

In some embodiments, the non-zwitterionic sulfonate-organosilanol compounds used in the solutions and compositions of the present invention have the following Formula (I): [(MO)(Q_n)Si(XCH₂SO3-)3-n]Y_2/nr ^+r (I) wherein: each Q is independently selected from hydroxyl, alkyl groups containing from 1 to 4 carbon atoms and alkoxy groups containing from 1 to 4 carbon atoms;

M is selected from hydrogen, alkali metals, and organic cations of strong organic bases having an average molecular weight of less than 150 and a pKa of greater than 11;

X is an organic linking group;

Y is selected from hydrogen, alkaline earth metals (e.g., magnesium, calcium, etc.), organic cations of protonated weak bases having an average molecular weight of less than 200 and a pKa of less than 11 (e.g., 4-aminopyridine, 2-methoxyethylamine, benzylamine, 2,4-dimethylimidazole, 3 -[2 -ethoxy (2- ethoxyethoxy)] propylamine), alkali metals, and organic cations of strong organic bases having an average molecular weight of less than 150 and a pKa of greater than 11 (e.g., ⁺N(CH₃)4, ⁺N(CH₂CH₃)4), provided that M is hydrogen when Y is selected from hydrogen, alkaline earth metals and organic cations of said protonated weak bases; r is equal to the valence of Y ; and n is 1 or 2.

Preferably, the non-zwitterionic compound of Formula (I) is an alkoxysilane compound (e.g., wherein Q is an alkoxy group containing from 1 to 4 carbon atoms).

The weight percentage of oxygen in these compounds of Formula (I) is at least 30%, and preferably at least 40%. Most preferably it is in the range of 45% to 55%. The weight percentage of silicon in these compounds is no greater than 15%. Each of these percentages is based on the weight of the compound in the water-free acid form.

The organic linking group X of Formula (I) is preferably selected from alkylene groups, cycloalkylene groups, alkyl-substituted cycloalkylene groups, hydroxy-substituted alkylene groups, hydroxy-substituted mono-oxoalkylene groups, divalent hydrocarbon groups having mono-oxo backbone substitution, divalent hydrocarbon groups having mono-thio backbone substitution, divalent hydrocarbon groups having monooxa-thio backbone substitution, divalent hydrocarbon groups having dioxo-thio backbone substitution, arylene groups, arylalkylene groups, alkylarylene groups and substituted alkylarylene groups. Most preferably X is selected from alkylene groups, hydroxy-substituted alkylene groups and hydroxy-substituted mono-oxoalkylene groups. Suitable examples of non-zwitterionic compounds of Formula (I) are described in U.S. Patent Nos. 4,152,165 (Langager et al.) and 4,338,377 (Beck et al.), and include, for example, the following:

(HO)3Si-CH2CH2CH2-O-CH2-CH(OH)-CH₂SO3’H⁺;

(HO)3Si-CH₂CH(OH)-CH₂SO3’H⁺;

(HO)3Si-CH2CH2CH₂SO3’H⁺;

(HO)3Si-C6H₄-CH2CH₂SO3’H⁺;

(HO)2Si-[CH₂CH₂SO3’H⁺]2;

(HO)-Si(CH3)2-CH2CH₂SO3’H⁺;

(NaO)(HO)2Si-CH2CH2CH2-O-CH2-CH(OH)-CH₂SO3’Na⁺; and (HO)3Si-CH₂CH₂SO3’K⁺.

In some embodiment, the surface layer comprises a zwitterionic silane. Examples of zwitterionic sulfonate-functional compounds include those disclosed in U.S. Patent No. 5,936,703 (Miyazaki et al.) and International Publication Nos. WO 2007/146680 and WO 2009/119690.

In some embodiments, the zwitterionic sulfonate-organosilanol compounds have the following Formula (II) wherein:

(R¹O)p-Si(R²)q-W-N⁺(R³)(R⁴)-(CH₂)m-SO3' (II) wherein: each R¹ is independently a hydrogen, methyl group, or ethyl group; each R² is independently a methyl group or an ethyl group; each R³ and R⁴ is independently a saturated or unsaturated, straight chain, branched, or cyclic organic group, which may be joined together, optionally with atoms of the group W, to form a ring;

W is an organic linking group; p and m are integers of 1 to 3; q is 0 or 1; and p + q = 3.

The organic linking group W of Formula (II) is preferably selected from saturated or unsaturated, straight chain, branched, or cyclic organic groups. The linking group W is preferably an alkylene group, which may include carbonyl groups, urethane groups, urea groups, heteroatoms such as oxygen, nitrogen, and sulfur, and combinations thereof. Examples of suitable linking groups W include alkylene groups, cycloalkylene groups, alkyl-substituted cycloalkylene groups, hydroxy-substituted alkylene groups, hydroxy-substituted mono-oxoalkylene groups, divalent hydrocarbon groups having mono-oxo backbone substitution, divalent hydrocarbon groups having mono-thiol backbone substitution, divalent hydrocarbon groups having mono-oxothiol backbone substitution, divalent hydrocarbon groups having dioxo-thiol backbone substitution, arylene groups, arylalkylene groups, alkylarylene groups and substituted alkylarylene groups.

Suitable examples of zwitterionic compounds of Formula (II) are described in US Patent No. 5,936,703 (Miyazaki et al.) and International Publication Nos. WO 2007/146680 and WO 2009/119690, and include the following zwitterionic functional groups (-W-N⁺(R³)(R⁴)-(CH2)_m-SO3'): In some embodiments, the zwitterionic silane is a sulfonate-organosilanol having the following

Formula (III) wherein:

(R¹O)p-Si(R²)q-CH2CH2CH2-N⁺(CH3)2-(CH2)m-SO3’ (III) wherein: each R¹ is independently a hydrogen, methyl group, or ethyl group; each R² is independently a methyl group or an ethyl group; p and m are integers of 1 to 3; q is 0 or 1; and p + q = 3.

Suitable examples of zwitterionic compounds of Formula (III) are described in US Patent No. 5,936,703 (Miyazaki et al.), including, for example:

(CH3O)3Si-CH2CH2CH2-N⁺(CH3)2-CH2CH₂CH2-SO3’; and (CH3CH2O)2Si(CH3)-CH2CH2CH2-N⁺(CH3)2-CH2CH₂CH2-SO3’.

Other examples of suitable zwitterionic compounds include the following:

Other suitable hydrophilic functional groups for silanes include but are not limited to phosphonate, carboxylate, gluconamide, sugar, polyvinyl alcohol, and quaternary ammonium.

The aqueous hydrophilic silane coating composition typically includes one or more hydrophilic silane compounds in an amount of at least 0.1, 0.5 or 1 wt.% based on the total weight of the coating solution. The hydrophilic silane coating composition typically includes the hydrophilic silane compound(s) in an amount of no greater than 10, 9, 8, 7, 6, or 5 wt.%, based on the total weight of the coating composition. Generally, for monolayer coating thicknesses, relatively dilute coating compositions are used. In some embodiments, more concentrated coating compositions can be used. In some embodiments, the surface may be subsequently rinsed to remove excess hydrophilic silane.

The hydrophilic silane coating composition preferably includes alcohol, water, or hydroalcoholic solutions (i.e., alcohol and/or water). Typically, such alcohols are lower alcohols (e.g., Ci to Cs alcohols, and more typically Ci to C4 alcohols), such as methanol, ethanol, propanol, 2-propanol, etc. Preferably, the hydrophilic-functional coating compositions are aqueous solutions. As it is used herein, the term “aqueous solution” refers to solutions containing 50 wt-% or greater water. Such solutions may employ water as the only solvent or they may employ combinations of water and organic solvents such as alcohol and acetone. Organic solvents may also be included in the hydrophilic treatment compositions so as to improve their freeze-thaw stability. Typically, the hydrophilic silane coating composition is dilute comprising at least 90 wt.% aqueous solution.

The hydrophilic silane coating composition can be acidic, basic, or neutral. The hydrophilic silane coating composition can optionally comprise surfactant and wetting agents as previously described.

In some embodiments, the hydrophilic silane coating composition optionally further comprise tetraalkoxysilane (e.g., tetraethylorthosilicate (“TEOS”)), oligomers thereof; and/or silicates such as alkyl polysilicates (e.g., poly(diethoxysiloxane)), lithium silicate, sodium silicate, potassium silicate, or combinations thereof, that can provide enhanced durability.

When present, such components are typically present in amounts less than the hydrophilic zwitterionic silane(s) or non-zwitterionic silane(s) previously described. In some embodiments, the weight ratio of hydrophilic (e.g. zwitterionic silane(s) or non-zwitterionic silane(s)) to silicate(s) is at least 1:1, 2:1, or 3:1.

The hydrophilic silane coating can optionally comprise water soluble polymers with hydroxyl groups. In the presence of acid, the hydroxyl groups on these polymers can condense to form a water insoluble coating. The hydroxyl groups can also react with silanol groups on a silica nanoparticle hardcoat. Suitable hydrophilic polymers with hydroxy groups include but are not limited to polyvinyl alcohol, hydroxy methyl cellulose, hydroxy ethyl cellulose, dextran, guar gum and mixtures thereof. When present, such water soluble polymers with hydroxyl groups are typically present in amounts less than the hydrophilic zwitterionic silane(s) or non-zwitterionic silane(s), as previously described.

The hydrophilic silane coating compositions typically contain at least 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 wt.% solids of hydrophilic zwitterionic silane(s) or non-zwitterionic silane(s), as previously described.

Hydrophilic silane coating compositions can be coated onto the cured hardcoat layer using conventional techniques, such as bar, roll, curtain, rotogravure, spray, wipe or dip coating techniques. The preferred methods include spray, bar and roll coating.

Once coated, the hydrophilic-functional article is typically dried at temperatures of 30°C to 200°C in a recirculating oven. An inert gas may be circulated. The temperature may be increased further to speed the drying process, depending on the heat tolerance of the substrate. Drying drives a condensation reaction between the hydrophilic coating and -OH groups on the surface of the hardcoat layer.

With reference to FIG. 3, the articles describes herein comprise a hardcoat layer 13, as previously described, disposed on a surface of a substrate 15. Substrates for dry erase surfaces can include for example glass, porcelain steel, painted steel, painted metal, painted hardboard, melamine, coated film, coated paper, and coated fiberboard sheets. In typical embodiments, the substrate comprises an organic polymeric material. The organic polymeric substrates may comprise polymeric sheets, films, or molded materials. In some favored embodiments, with reference to FIG. 1 the articles describes herein comprise a hardcoat layer 13, as previously described, disposed on a surface of a substrate 15; and a surface layer 14 disposed on major surface 16 of the hydrolyzed and cured hardcoat layer.

In another embodiment, with reference to FIG. 2 the article comprises a hardcoat layer 13, as previously described, disposed on both major surfaces of a substrate 15; and a hydrophilic surface layers 14 disposed on both major surfaces 16 of the hydrolyzed and cured hardcoat layer 13. Such article is suitable for use as a rewritable notebook page, wherein both sides of the page are rewritable.

The hardcoat together with the hydrophilic surface layer increases the hydrophilicity of the substrate. As used herein, “hydrophilic” is used to refer to a surface that it is wet by aqueous solutions, and does not express whether or not the layer absorbs aqueous solutions. Surfaces on which drops of water or aqueous solutions exhibit a static water contact angle of less than 50° are referred to as “hydrophilic.” Hydrophobic substrates have a water contact angle of 50° or greater.

In some embodiments, the hardcoat has a static contact angle with water of at least 95, 100, or 105 degrees. In some embodiments, the hardcoat has a static contact angle with n-hexadecane of at least 25, 30, or 35 degrees and typically no greater than 40 degrees.

In some embodiments, the hardcoat layer, hydrophilic surface layer, and substrates of rewritable or anti-fog articles may be transparent or translucent to visible light. The term transparent means transmitting at least about 85, 90, 95% or greater of incident light in the visible spectrum (about 400 to about 700 nm wavelength). The transparent substrate together with the transparent hardcoat the hydrophilic surface layer can be utilized as a rewritable cover film. When the substrate further comprises a transparent adhesive on the back of the substrate (i.e., the opposing surface as the hardcoat and hydrophilic surface layer), the cover film can be adhesively bonded to a (e,g., printed paper) substrate.

Substrates used herein may be flexible or inflexible as desired. Illustrative examples of suitable substrates that comprise an organic polymer material include polyester (e.g., polyethylene terephthalate, polybutyleneterephthalate), polycarbonate, allyldiglycolcarbonate, polyacrylates, such as polymethylmethacrylate, polystyrene, polysulfone, polyethersulfone, homo-epoxy polymers, epoxy addition polymers with polydiamines, polydithiols, polyethylene copolymers, fluorinated surfaces, cellulose esters such as acetate and butyrate, glass, ceramic, porcelain, coated paper, metal, organic and inorganic composite surfaces and the like, including blends and laminates thereof.

In other embodiments, the substrate may be colored or opaque. It has been found that the composition provides easily cleanable surfaces to substrates such as flexible films used label applications. Flexible films may be made from polyesters such as PET or polyolefins such as PP (polypropylene), PE (polyethylene) and PVC (polyvinyl chloride). The substrate can be formed into a film using conventional filmmaking techniques such as extrusion of the substrate resin into a film and optional uniaxial or biaxial orientation of the extruded film. The substrate can be treated to improve adhesion between the substrate and the hardcoat coating, using, e.g., chemical treatment, corona treatment such as air or nitrogen corona, plasma, flame, or actinic radiation. If desired, an optional tie layer (not shown) can also be applied between the substrate and the hardcoat coating composition to increase the interlayer adhesion. The other major surface of the substrate 22 may also be treated using the above-described treatments to improve adhesion between the substrate and a (e.g. pressure sensitive) adhesive layer 18 temporarily covered by a release liner 20. Major surface 22 of substrate 15 of FIG. 2 may also comprise such adhesive and release liner layers. The substrate may be provided with graphics, such as words or symbols or a printed pattern such as lines, grids, dots, geometric shapes, etc. including rewritable graphs, charts, lists (e.g., shopping, to-do), planners, calendar pages (e.g., hourly, daily, weekly, monthly, yearly), educational and hospital forms, etc. Various printing techniques can be utilized included flexographic, gravure, and inkjet printing.

In still other embodiments, the substrate can be a metal or have a metal surface (e.g., vapor deposited metals) such as aluminum or stainless steel.

In some embodiments, articles with an anti-fog surface are described. Illustrative articles include medical and non-medical protective eye wear including glasses, goggles, face masks, face shields, and respirators; as well as mirrors, motor vehicle windows, and windshields.

In other embodiments, articles that retard dew formation are described. Illustrative articles include signs, retroreflective and graphic signage, informative and advertising panels, license plates for automotive vehicles, raised pavement markers, reflectors and linear delineation systems (LDS), and advertisement signs and light boxes, platforms or display supports bearing visually observable information.

The surface layers and articles described herein can also provide anti-graffiti and easy-to-clean indoor and outdoor surfaces for homes and various other buildings as well as vehicles such as trains, planes and automobiles. The surface layers and articles may be applied to walls, cabinets, countertops, windows, etc.

In some embodiments, articles with a writable and rewritable surface are described. Illustrative articles include notebooks and (e.g., lined) loose pages thereof, notebook cover, notebook divider, note cards, planners, label, name tags, file folder, file tab or film suitable for attachment (e.g. with a pressure sensitive adhesive) to a surface, such as a wall (e.g. wall paper and films).

Writable and rewritable articles can further comprise such other optional components as frames, means for storing materials and tools such as writing instruments, erasers, cloths, note paper, etc., handles for carrying, protective covers, means for hanging on vertical surfaces, easels, etc.

In some embodiments, the (e.g. dry erase film) articles can further comprise a (e.g. pressures sensitive) adhesive coating on the back of the substrate and a release liner. In another embodiment, a method of using an article is described comprising providing an article comprising a substrate and a hydrolyzed and condensed hardcoat as described herein, and preferably a surface layer comprising a hydrophilic silane; writing on the surface layer with a marker; and removing the writing.

The surfaces of dry erase articles exhibit excellent writability with various writing instruments such as a permanent markers, dry erase markers, pens, gel pens, pencils, crayon, paint. Such writing instruments utilize both water-based and solvent-based colorants that include pigment and dyes. In some embodiments, removing the writing comprises wiping the rewritable surface with an eraser, cloth or paper towel. Herein, “wiping” refers to gentle wiping, typically by hand, with for example, a tissue, paper towel, or a cloth, without significant pressure (e.g., generally, no more than 800 grams) for one or more strokes or rubs (typically, only a few are needed). In some embodiment, removing further comprises applying an aqueous cleaning solution optionally comprising organic solvent(s), to the surface layer. The aqueous cleaning solution may comprise cationic, anionic or/and nonionic surfactants as known in the art. Notably, permanent marker writing can be removed the by spraying water and wiping the rewritable surface with a microfiber cloth or paper towel.

In some embodiments, the surface layer of the article is suitable for rewriting on the surface layer and removing the writing multiple times.

Referring now to FIG. 4, a flowchart depicts how content can be added to embodiments herein to reproduced in digital form for backup, editing, and the like. At block 400, a digital identifier (QR code, barcode, and/or any other identifier capable of providing unique identification) may be added to any suitable layer of the rewritable surface. The digital identifier may be pre-printed onto a layer of the rewritable surface, added via an adhesive, or the like. At block 402, content (writing, drawings, and the like) may be added to the surface layer utilizing any suitable type of writing instrument as described herein.

At block 404, writing on the surface layer may be digitized. Any suitable image capture device (see FIG. 5, by way of non-limiting example) may be utilized. The writing as captured may be associated with the digital identifier for storage/retrieval in any suitable format and/or location (database, cloud, server, and the like). At block 406, some or all of the writing/content on the surface layer may be erased utilizing any suitable type of erasing instrument (marker erase or the like). At block 408, new writing may be added, which may include overwriting what was previously erased at block 406. The updated content may similarly be digitized utilizing the digital identifier. The updated writing may be stored in a manner that replaces the previous writing on the surface. In another embodiment, the updated writing may be stored as a newer version, such that multiple versions of what is written on the surface layer may be stored and associated with the digital identifier.

Referring now to FIG. 5, a block diagram illustrates computing hardware, such as an exemplary computing device 500, through which embodiments of the disclosure can be implemented. The computing device 500 described herein is but one example of a suitable computing device and does not suggest any limitation on the scope of any embodiments presented. Nothing illustrated or described with respect to the computing device 500 should be interpreted as being required or as creating any type of dependency with respect to any element or plurality of elements. In various embodiments, the computing device 500 may include, but need not be limited to, a desktop, laptop, server, client, tablet, smartphone, computing cloud or any other type of device that can utilize data. In an embodiment, the computing device 500 includes at least one processor 502 and memory comprising non-volatile memory 508 and/or volatile memory 510. The computing device 500 can include one or more displays, display hardware, and/or output devices 504 such as, for example, AR/VR/MR/XR hardware, monitors, speakers, headphones, projectors, wearabledisplays, holographic displays, and/or printers. Output devices 504 may further include, for example, displays and/or speakers, devices that emit energy (radio, microwave, infrared, visible light, ultraviolet, x- ray and gamma ray), electronic output devices (Wi-Fi, radar, laser, etc.), audio (of any frequency), and the like.

The computing device 500 may further include one or more input devices 506 which can include, by way of example, any type of mouse, keyboard, disk/media drive, memory stick/thumb-drive, memory card, pen, touch-input device, biometric scanner, gaze and/or blink tracker, tracker, voice/auditory input device, motion-detector, camera, scale, and any device capable of measuring data such as motion data (e.g., an accelerometer, GPS, a magnetometer, a gyroscope, etc.), biometric data (e.g., blood pressure, pulse, heart rate, perspiration, temperature, voice, facial-recognition, motion/gesture tracking, gaze tracking, iris or other types of eye recognition, hand geometry, oxygen saturation, glucose level, fingerprint, DNA, dental records, weight, or any other suitable type of biometric data, etc.), video/still images, and audio (including human-audible and human-inaudible ultrasonic sound waves). Input devices 506 may include any type of device capable of receiving data, whether from another device, visual and/or audio data captured from the real world, object detection data, and the like. Input devices 506 may include cameras (with or without audio recording), such as digital and/or analog cameras, still cameras, video cameras, thermal imaging cameras, infrared cameras, cameras with a charge-couple display, night-vision cameras, three-dimensional cameras, webcams, audio recorders, and the like.

The computing device 500 typically includes non-volatile memory 508 (e.g., ROM, flash memory, etc.), volatile memory 510 (e.g., RAM, etc.), or a combination thereof. A network interface 512 can facilitate communications over a network 514 with other data source such as a database 518 via wires, a wide area network, a local area network, a personal area network, a cellular network, a satellite network, and the like. Suitable local area networks may include wired Ethernet and/or wireless technologies such as, for example, wireless fidelity (Wi-Fi). Suitable personal area networks may include wireless technologies such as, for example, IrDA, Bluetooth, Wireless USB, Z-Wave, ZigBee, and/or other near field communication protocols. Suitable personal area networks may similarly include wired computer buses such as, for example, USB and FireWire. Suitable cellular networks may include, but are not limited to, technologies such as LTE, WiMAX, UMTS, CDMA, and GSM. Network interface 512 can be communicatively coupled to any device capable of transmitting and/or receiving data via one or more network(s) 514. Accordingly, the network interface 512 can include a communication transceiver for sending and/or receiving any wired or wireless communication. For example, the network interface 512 may include an antenna, a modem, LAN port, Wi-Fi card, WiMax card, mobile communications hardware, near-field communication hardware, satellite communication hardware and/or any wired or wireless hardware for communicating with other networks and/or devices.

A computer-readable medium 516 comprises one or more plurality of computer readable mediums, each of which is non-transitory. A computer readable medium may reside, for example, within an input device 506, non-volatile memory 508, volatile memory 510, or any combination thereof. A readable storage medium can include tangible media that is able to store instructions associated with, or used by, a device or system. A computer readable medium, also referred to herein as a non-transitory computer readable medium, includes, by way of non-limiting examples: RAM, ROM, cache, fiber optics, EPROM/Flash memory, CD/DVD/BD-ROM, hard disk drives, solid-state storage, optical or magnetic storage devices, diskettes, electrical connections having a wire, or any combination thereof. A non-transitory computer readable medium may also include, for example, a system or device that is of a magnetic, optical, semiconductor, or electronic type. A non-transitory computer readable medium excludes carrier waves and/or propagated signals taking any number of forms such as optical, electromagnetic, or combinations thereof.

The computing device 500 may include one or more network interfaces 512 to facilitate communication with one or more remote devices, which may include, for example, client and/or server devices. The network interface 512 may also be described as a communications module, as these terms may be used interchangeably. The database 518 is depicted as being accessible over the network 514 and may reside within a server, the cloud, or any other configuration to support being able to remotely access data and store data in the database 518.

Due to the cleanability, the hardcoat layer described herein is also suitable for other articles such as coatings for (e.g. flexible) electronics including insulating layers (e.g. dielectric coatings) and protective coatings and films for various electronic components such as (e.g. LCD, LED, and OLED) display surfaces and lenses of cameras and sensors.

Other articles include various interior or exterior surfaces or components of a) a surface or component of a vehicle (e.g. automobile, bus, train, airplane, boat, ambulances, ships) as well as motorized and non-motorized shared vehicles such as car, scooters and bicycles including head rests, dashboards, door panels, window shutter (e.g. of an airplane), gear shifter, seat belt buckle, instrument and button panels, (e.g. plastic) seat back trays and arm rests, railings, cabin siding, luggage compartment, steering wheels, handlebars; b) housing and cases of an electronic device (e.g. phone, laptop, tablet, or computer) as well as keyboards and mouses (including mouse pads) and touchscreens, projectors, printers, remote control devices, locks, chargers (including cords & docking stations), fobs, video and arcade games, slot machines, automatic teller machines; (e.g. handheld) scanners, key cards, and point of sale electronic devices such as credit card readers, keypads, stylists, cash registers, barcode scanner, payment kiosks; c) packaging film (e.g. for food or medical products) and polymeric shipping products including labels, mailers, boxes, totes, and bubble-wrap; d) food preparation and dining surfaces, containers (including plates, bowls, cubs, water bottles) and films including galleys, carts, cutting boards, lunch boxes, thermos, appliances (e.g. microwave, stove, ovens, blenders, toasters, coffee makers, refrigerator including shelves and drawers), beverage dispensers, grills, utensils (e.g. especially handles thereof), menus, condiments bottles, salt & pepper shakers, table tops and chairs (especially for public dining in restaurants, dorms, nursing homes, and prisons), garbage and recyclable containers; e) (e.g. non-sterile) surfaces of a medical, dental, or laboratory facility or medical, dental, or laboratory equipment (e.g. defibulators, ventilators and CPAPs (especially masks thereof), face shields, crutches, wheelchairs, bed rails, breast pump devices, IV pole and bags, curing lights (e.g. for dental materials), exam tables, surfaces of massage devices; f) surfaces or components of furniture (e.g. desks, tables, chairs, seats and armrests); g) handles (e.g. knob, pull, levers including locks) of articles including furniture, doors of buildings, turn styles, appliances, vehicles, shopping carts and baskets, exercise equipment, (e.g. cooking) utensils, tools, handlebars, levers of window blinds, microphone, luggage, etc.; h) building surfaces (including escalators and elevators) such as doors, railings, walls, flooring, countertops, desktops, cabinets, lockers, windows (e.g. sills), door bells, electrical modulators (e.g. light switches, dimmers, and outlets including plates thereof); i) surfaces and components of lavatories (e.g. sink, toilet surfaces (e.g. levers), drain caps, shower walls, bathtub, vanity, countertop); j) surface or liner of a swimming pool or roofing material; k) personal items including toothbrushes, eye glass frames, shoes, clothing, helmets, head bands, hard hats, headphones, footwear (e.g. shoes and boots), handbags, back packs; l) articles for children including toys, pacifiers, bottles, teethers, car seats, cribs, changing tables, and playground equipment; m) cleaning equipment (e.g. vacuum, mop, scrub bmsh, dusters, toilet bowl cleaners, plunger, brooms) n) protective athletic and sports equipment (e.g. helmets, guards, balls for various sports including football, basketball, soccer, and golf); o) exercise, spa, and salon (e.g. hair styling and nail) equipment (e.g. weights, yoga mats) p) office and schools supplies and equipment including writing instruments (e.g. pencils, pens, markers), writable surfaces (including films and white boards), erasers, file folders, book and notebook covers, scanner and copy machines; q) manufacturing surfaces and equipment including conveyor belts, control panels for machine operation (e.g. of an assembly line).

The cleanable surface is particularly advantageous for congregate living facilities such as military housing, prisons, dorms, nursing homes, apartments, hotels; public places such as offices, schools, arenas, casinos, bowling alleys, golf courses, arcades, gyms, salons, spas, shopping centers, airports, train stations; and public transportation.

In some embodiments, the film for application to vehicle or building surfaces etc. may be characterized as an architectural, decorative, or graphic film. Graphic films typically include patterns, images, or other visual indicia. The graphic film may be a printed film, or the graphic may be created by means other than printing. For example, the graphic film may be perforated reflective film with a patterned arrangement of perforations. Such films comprise an organic polymer layer such as polyvinyl chloride, polyurethane, or polyester. The organic polymer layer further comprises a design pattern having the appearance for example of wood, leather, metal, concrete, ceramic, as well as various (e.g. abstract) designs. The surface finish is typically matte or glossy. EXAMPLES

Unless otherwise noted or readily apparent from the context, all parts, percentages, ratios, etc. in the Examples and the rest of the specification are by weight. The materials Table (below) lists materials used in the examples and their sources.

Table 1. Abbreviation and description of the materials used in the examples

Test Methods

Flexibility - The flexibility of the hardcoat samples was assessed by bending sample strips measuring approximately 2” by 4” using a pentagon mandrel bend tester equipped with a series of bars of varying diameters (1”, 5/8”, !/2”, 3/8”, V", and 1/8”). Throughout the test, the coating side of the sample faced outward to subject it to a stretch bending mode, as opposed to a compressed bending mode where the coating side would face inward. Each bend was held for 40 seconds, starting from the 1 ” bar diameter. Subsequently, the bending location was generously covered with Expo Black dry erase marker ink and wiped off with a dry microfiber cloth. Failure to completely erase the ink, indicating ink ghosting, suggested crack generation due to bending at that specific diameter. The crack can also be confirmed by optical microscope. If a sample passed the test for the 1 ” bar, it progressed to the next smaller bar diameter and underwent the same evaluation. This process continued until the sample exhibited bending failure. Samples that successfully passed the smallest bar diameter (1/8”) were then subjected to further evaluations: first, a soft crease (lightly folded) held for 40 seconds, followed by a hard crease (tightly folded) also held for 40 seconds.

For full construction coating samples (having a hydrophilic surface layer applied to the hardcoat), the same bending protocol was followed, except the samples were covered with Sharpie Black permanent marker ink and wiped off with water for evaluation.

Hardcoat Abrasion - The durability of the hardcoat samples was evaluated using a 5900 Reciprocating Abraser from Taber Industries. Samples were cut to approximately 3” by 6” in size and secured onto the test panel with the coating side facing upwards, using 3M 9415 transfer adhesive tape. A Black Expo dry erase marker was used to completely cover the surface in ink (as the abrasive). Each erasing puck measured about 2” in diameter, and a Scotch Brite Non-scratch scour pad, cut to the same size, was affixed to the puck as the abrasion medium. Each Taber arm was loaded with a 2 kg weight and horizontally aligned using the alignment level. The abraser machine was turned on, setting the "total cycles" to 2400 and "speed cycles/min" to 60, ensuring that each sample underwent 2400 back-and-forth cycles at a speed of 60 cycles/min. Following abrasion, the coating surface was examined to assess the damage caused by the abrasion from the Scotch Brite pad.

Full Construction Abrasion - The durability of the full construction samples underwent evaluation using a similar setup on the Taber abraser, with the exception of the abrasion medium being Kleenex soft tissue (without any added moisturizer). The tissue was folded twice in the middle and cut to a size of 2” by 2”, then secured onto the puck. The abraser machine was activated, setting the "total cycles" to 400 and "speed cycles/min" to 60 for a complete round of analysis. After each round, any residue from the Black Expo dry erase marker was wiped clean, followed by scribbling with a Black Sharpie permanent marker ink on the surface. Once the ink was dried, the sample was tested by spraying with water, and the removability of the ink using a microfiber cloth was assessed. If the ink was completely removed without leaving any ghosting or staining, the test continued until a total of 6 rounds of repeated analysis were completed. The number of rounds that each sample passed the testing was recorded as the abrasion score, with "0" indicating the lowest score and "6" indicating the best score.

Writability - The writability testing of the matte full construction samples were performed using a series of different pencils and ballpoint pens with a pen tip size varied from 1.0 to 0.38 mm. The pens included in the testing are: Staples® Retractable ballpoint pen 1.0 mm, BIC ballpoint pen 1.0 mm, BIC Xtra Life Mechanical Pencils 0.7 mm, Frixion® gel pen 0.7 mm, Pilot® G-2 gel pen 0.7 mm, Pilot® G-2 gel pen 0.5 mm, Muji gel pen 0.5 mm, and Muji gel pen 0.38 mm. The testing involves drawing a series of horizontal, vertical, and wavy lines at a normal writing speed and force and the writability was rated by ink continuity on the surface as poor (fail to write with pencil), medium (good writability with pencil and pens that are >0.5 mm), and good (good writability with pens that are > 0.38 mm), and excellent (good writability with all of the testing pens).

Erasability - The erasability testing of the matte full construction samples were performed by writing with the following permanent markers : Sharpie Black, Sharpie Red, BIC Black, BIC Blue, AVERY Black, and AVERY Red. Then, the sample was generously sprayed with water and clean with a microfiber cloth. The easiness and cleanness of ink removal was analyzed by two repeated writing and erasing with the markers. Good means all the ink from the described permanent markers was removed.

Anti-fogging Test Method

Antifog test was conducted by immersing the film samples into water for an horn. The water was circulated by continuously replenishing fresh water. After water soaking, the film samples were dried overnight at ambient condition. The film samples were separately exposed to a water vapor generated by heating a 500 mL beaker of water at 60 °C for 1 minute and facing the film sample hydrophilic side down against a one-inch round hole of a glass cover placed over the beaker. A good antifogging sample remained clear after 1 minute. General procedure for preparing hardcoat solution

Hardcoat base solutions are prepared using the following procedure: Nanosilica suspension solution (either 1130 or 2327, or a combination of both at varied ratios) was added into a glass jar equipped with a magnetic stir bar. This was followed by addition of AA into the solution to serve as a catalyst so that the ratio of nanosilica solids to AA is set to 6/1 to drop the pH of nanosilica solution to 4-5. Water was added to 2327 to from a 30 wt.% solids solution. Silane monomer(s) (MTES) were then introduced into the acidic nanosilica solution while stirring. The determination of the silane's total weight involved calculating it in accordance with the solid weight of the overall nanosilica solid weight, for example, a 3/1 MTES/1130 ratio indicates the weight of MTES is three times of the 1130 nanosilica solid weight. 2- methoxy propanol was then added into the solution at a weight ratio with water of 1:1. The base solution hydrolyzed for 1-2 days at ambient temperature. After hydrolysis, the solution generally has a clear homogenous appearance.

Silane terminated polymers or (methjacrylic copolymers (e.g. Elvacite) were incorporated in the form of a 30 wt.% solution of 2-methoxy propanol or IPA. The polymer solution was introduced either through post-addition into the hydrolyzed base solution or added concurrently to co-hydrolyze with the base solution. Finally, 0.5% of BYK-UV 3500 surfactant was incorporated into the solution to improve the coating quality. The reaction was stirred in the enclosed jar for 24-48 hours, depending on the reaction scale and stirring rate of the reactor.

Coating of the hardcoat: The hardcoat solutions were coated with either Mayer rods or gravure rolls on a Mitsubishi or SKC primed PET substrate at a coating thickness of 3-5 micron after drying in the oven at 280°F-300°F for 2 min. During drying, the hydrolyzed polymer and silane terminated polymers cocondensed.

“Full construction samples” is used herein to refer to samples having a surface layer comprising a hydrophilic silane disposed on the hardcoat layer. The full construction samples prepared by subjecting the hardcoat sample surface to air corona treatment at a dosage of 2-6 J/cm² to activate the surface. Subsequently, the samples were coated with a super-hydrophilic (SHP) aqueous solution, produced by blending Zwitterionic silane (ZS) and LSS-75 at a 60/40 solids ratio. The resulting SHP solution, containing 4 wt% solids in water, was applied using either a Mayer rod or a gravure roll to achieve a thickness range of 100-200 nm after baking at temperatures between 280°F -300°F for 2 minutes. During drying, condensation reaction between the corona treated siloxane hardcoat surface and zwitterionic silane occurred.

Unless specified otherwise, the coating compositions were translucent, indicative of acceptable coating quality. N/T - not tested Table 2. Comp. A comprises 3/1, MTES/2327 or in other words 75 wt.% MTES and 25 wt.% 2327. Assuming 100% hydrolysis, all the ethoxy group have been hydrolyzed to ethanol. Thus, the hydrolyzed and condensed hardcoat contains two components MeSiC>3/2 (Mw = 67) and SiO2 (Mw=60). The % carbon of the R¹ group of the silane monomer (e.g. methyl) can be calculated as follows: 12 X 0.75/(67 X 0.75 + 60 X 0.25) = 13.7% carbon (i.e. derived from the R¹ group)

Claims

What is claimed is:

1. An article comprising:

A) a substrate;

B) a hardcoat layer disposed on the substrate wherein the hardcoat layer comprises a hydrolyzed and condensed reaction product of a composition comprising: i) first silane monomer(s) having the formula R ¹ Si (O y, wherein R and R¹ is methyl or ethyl; ii) silica nanoparticles having a primary average particle size of 10 to 50 nm in an amount greater than 30 wt.%;

2. The article of claim 1 wherein the amount of i) is at least 25, 30, 35, 40, 45, 50, 55, 60, 65, or 70 wt.% of the composition.

3. The article of claims 1-2 wherein the composition comprises no greater than 20, 15, 10, 5, or 1 wt.% of silane monomer(s) having the formula Si(OR)4 wherein R and R¹ is methyl or ethyl is no greater than 20, 15, 10, 5, or 1 wt.% of the composition.

4. The article of claims 1-3 wherein the composition further comprises at least one organic polymer comprises one or more functional groups that react with hydrolyzed OR groups of the first silane monomer(s).

5. The article of claim 3 wherein the organic polymer is an alkoxysilane terminated polymer comprises at least one, two, or three alkoxy silane groups.

6. The article of claim 5 wherein the alkoxysilane terminated polymers comprise polyester or polyether.

7. The article of claim 5-6 wherein the alkoxysilane terminated polymer has the formula: wherein R¹ is independently CH₃ or CH2CH3;

R³ is independently CH3, CH2CH3, OCH3, or OCH2CH3;

L is a covalent bond or divalent organic linking group; and n is 1, 2, 3, or 4.

8. The article of claims 4-7 wherein the organic polymer is a (meth)acrylic copolymer having a hydroxyl number of at least 50, 75, 100, or 125 mg KOH/g of copolymer.

9. The article of claims 4-8 wherein the organic polymer has a molecular weight ranging from 2000 to 100,000 Da.

10. The article of claim 1-9 wherein the composition comprises no greater than 20, 15, 10 or 5 wt.% of organic polymer.

11. The article of claims 1-10 wherein the hardcoat layer further comprises inorganic or organic matte particles.

12. The article of claims 1-11 wherein the article or cured and dried hardcoat layer has a mandrel bend of less than 1/4 inch (6.35 mm) or 1/8 inch (3.18 mm) without cracking.

13. The article of claims 1-12 wherein said hydrophilic silane comprises a zwitterionic silane.

14. The article of claims 1-13 wherein the surface layer further comprises lithium silicate, sodium silicate, potassium silicate, or combinations thereof.

15. The article of claims 1-14 wherein the substrate comprises an organic polymeric material.

16. The article of claims 1-15 wherein the substrate further comprises a printed pattern, lines, grids, dots, geometric shapes, etc.

17. The article of claims 1-16 wherein the dried and cured surface layer has a 60 or 85 degree gloss of less than 10 or 5.

18. The article of claims 1-17 wherein the surface layer is a rewritable with a permanent marker, dry erase marker, pen, gel pen, pencil, crayon, paint, or combination thereof.

19. The article of claims 1-18 wherein the article is a notebook, notebook cover, notebook divider, label, file folder, or file tab.

20. The article of claim 1-19 wherein the article is a film further comprising an adhesive of the opposing surface of the substrate.

21. The article of claims 1-20 wherein the article is a surface layer of a protective eye wear.

22. An article comprising:

A) a substrate;

B) a hardcoat layer disposed on the substrate wherein the hardcoat layer comprising a hydrolyzed and condensed reaction product of a composition comprising: i) first silane monomer(s) having the formula R^Si OR^ wherein R and R¹ is methyl or ethyl and silica nanoparticles; wherein the hydrolyzed and condensed reaction product has a R¹ carbon concentration of less than the calculated amount of the same composition comprising 70 wt.% first silane monomer(s) and a mandrel bend of less than 1/4 inch (6.35 mm) without cracking;

23. The article of claim 22 further characterized by claims 2-13.

24. The hydrolyzed and condensed reaction product of the hardcoat composition of claims 22-23.

25. An article comprising a substrate and the hydrolyzed and condensed reaction product of the hardcoat composition of claims 22-23.

26. A method of using an article: providing an article according to claims 1-21 and 25; writing on the surface layer; and removing the writing.

27. The method of claim 26 wherein writing comprising writing with permanent markers, dry erase markers, pens, gel pens, pencils, crayon, paint.

28. The method of claims 26-27 wherein permanent marker writing can be removed the by spraying water and wiping the rewritable surface with a microfiber cloth or paper towel.

29. The method of claims 26-28 further comprising rewriting on the surface layer and removing the writing multiple times.

30. A method utilizing the article of claims 1-25 comprising: adding content to the surface layer; capturing an image of the content and a digital identifier; and storing the content in the captured image such that the captured image is associated with the digital identifier.

31. The method of claim 30 further comprising: modifying at least some of the content from the surface layer; capturing another image with the modified content and the digital identifier; and replacing the previous content associated with the digital identifier such with the modified content.