Articles comprising polymer sheets and coatings, and coated substrates comprising the same.

Abstract

The coated substrate may include a transparent substrate and an article positioned on at least a portion of the first surface of the substrate. The article may include a polymer sheet having a first surface and a second surface opposite the first surface. The polymer sheet may include a neutralized ethylene acid copolymer material containing carboxylic acid groups. The carboxylic acid groups of the ethylene acid copolymer may be at least partially neutralized with metal ions. The article may further include a coating in direct contact with at least a portion of the first surface of the polymer sheet. The coating may include an acrylic material. The coating may be an air-contact layer.

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 520,239, filed Aug. 17, 2023, the entire content of which is incorporated herein by reference.

[0002] The present disclosure relates to polymeric materials, and more particularly, to coated polymeric sheets.

Background Art

[0003] Transparent substrates often lack sufficient protective properties for their intended use. For example, portable electronic devices such as mobile phones often have large, expensive, and fragile screens. Extensive research has been conducted on the development of more scratch - resistant screens and screen protectors. Screen protectors can be applied either in the factory or by the end - user. In either case, screen protectors have the advantage of having acceptable adhesion to the screen, relatively high impact resistance, and / or relatively high hardness (to provide scratch resistance and / or crack resistance).

Summary of the Invention

[0004] There is a need for new articles that provide one or more of acceptable adhesion to a screen, relatively high impact resistance, and / or relatively high hardness. Such articles may be useful as screen protectors in some embodiments. As described herein, such articles may include a polymeric sheet and a coating in contact with the polymeric sheet. In particular, the polymeric sheet may include a neutralized ethylene acid copolymer at least partially neutralized with metal ions, and the coating may include an acrylic material. In one or more embodiments, such a combination of materials can provide beneficial effects such as enhanced scratch resistance and / or impact resistance while maintaining optical properties suitable for a screen protector.

[0005] According to one or more embodiments, the article may include a polymer sheet having a first surface and a second surface opposite the first surface. The polymer sheet may include a neutralized ethylene acid copolymer material containing carboxylic acid groups. The carboxylic acid groups of the ethylene acid copolymer may be at least partially neutralized with metal ions. The article may further include a coating in direct contact with at least a portion of the first surface of the polymer sheet. The coating may include an acrylic material. The coating may be an air-contact layer.

[0006] According to one or more additional embodiments, the coated substrate may include a transparent substrate and an article. The article may be on at least a portion of the first surface of the substrate. The article may include a polymer sheet having a first surface and a second surface opposite the first surface. The polymer sheet may include a neutralized ethylene acid copolymer material containing carboxylic acid groups. The carboxylic acid groups of the ethylene acid copolymer may be at least partially neutralized with metal ions. The article may further include a coating in direct contact with at least a portion of the first surface of the polymer sheet. The coating may include an acrylic material. The coating may be an air-contact layer.

[0007] These and other embodiments will be described in more detail in embodiments for carrying out the invention. It should be understood that both the above general description and the following detailed description represent embodiments of the technology disclosed herein and are intended to provide an overview or framework for understanding the nature and features of the technology as claimed. The accompanying drawings are included to provide a further understanding of the technology disclosed herein, are incorporated into this specification, and constitute part thereof. The drawings illustrate various embodiments and, together with the description, help to illustrate the principles and operation of the technology disclosed herein. Additionally, the drawings and description are intended to be illustrative only and are not intended to limit the scope of the claims in any way. [Brief explanation of the drawing]

[0008] The following detailed description of specific embodiments of this disclosure will be best understood in conjunction with the following drawings, in which similar structures are shown with similar reference numerals.

[0009] [Figure 1] A schematic cross-sectional view of an article according to one or more embodiments described herein is shown. [Figure 2] A schematic cross-sectional view of another article according to one or more embodiments described herein is shown.

[0010] Various embodiments will be described in more detail below, some of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals are used throughout the drawings to refer to the same or similar parts. [Modes for carrying out the invention]

[0011] One or more embodiments of articles comprising polymer sheets and coatings are described herein. The composition of the polymer sheets and coatings, as well as their materials, are described in general terms.

[0012] A "copolymer" is defined as a polymer compound prepared by polymerizing several different types of monomers. Trace amounts of impurities (e.g., catalyst residues) may be incorporated into and / or within the copolymer.

[0013] The term "neutralization rate" is defined as the degree of neutralization or ionization of all acidic portions present in a neutralized ethylene acid copolymer material. The neutralization rate can range from 0 to over 100 percent. At zero percent, no ionization of the acidic groups occurred. At 100 percent, all acidic groups were neutralized or ionized. If more than 100 percent of the acidic groups are neutralized, the neutralized cations loosely associate with the acidic groups.

[0014] The term "haze" is defined as the percentage of transmitted light that deviates from the incident beam due to forward scattering as it passes through a film sample. Haze may also be defined as a measure of the intensity of transmitted light scattered beyond 2.5° (expressed as a percentage of total transmitted light). Haze can appear as a milky, hazy, or cloudy region when viewed through a film sample. Lower values ​​indicate a low "haze" measurement.

[0015] The present disclosure will now be described with reference to specific embodiments. As shown in Figure 1, the coated substrate 100 may include a transparent substrate 106 and an article 108 positioned on at least a portion of the first surface of the substrate 106. The article 108 may include a polymer sheet 104 having a first surface and a second surface opposite the first surface. The polymer sheet 104 comprises a neutralized ethylene acid copolymer material containing carboxylic acid groups, the carboxylic acid groups of the ethylene acid copolymer being at least partially neutralized with metal ions. The article 108 may further include a coating 102 in direct contact with at least a portion of the first surface of the polymer sheet 104. The coating 102 may include an acrylic material. The coating 102 may be an air-contact layer. The article 108 may be suitable for attachment to the substrate 106, or may already be attached to the substrate 106, thereby forming the coated substrate 100.

[0016] Referring further to Figure 1, in one or more embodiments, the polymer sheet 104 may be positioned next to the coating 102. In embodiments, the polymer sheet 104 may be in direct contact with the coating 102. In embodiments where article 108 forms part of a coated substrate 100, the polymer sheet 104 may be positioned between the coating 102 and the substrate 106. In embodiments, the polymer sheet 104 may be in direct contact with the substrate 106. Alternatively, as shown in Figure 2, the polymer sheet 104 may be separated from the substrate 106 by an adhesive layer 202. In embodiments of article 108 where article 108 is not positioned next to the substrate 106, the polymer sheet 104 may be an air-contact layer. Alternatively, in embodiments of article 108 where article 108 is not positioned next to the substrate 106, the polymer sheet 104 may be positioned between the adhesive layer 202 and the coating 102, and the adhesive layer 202 may be an air-contact layer.

[0017] As previously stated herein, the polymer sheet 104 may contain a neutralized ethylene acid copolymer. The neutralized ethylene acid copolymer may be an ionomer. The neutralized ethylene acid copolymer may contain ethylene and a carboxylic acid, such as acrylic acid, methacrylic acid, or both. The carboxylic acid functional group may be at least partially neutralized with a metal such as sodium, magnesium, lithium, or zinc. "Base resin" refers to the composition of the ethylene acid copolymer before neutralization to form the neutralized ethylene acid copolymer. The weight percentage of acid in the base resin (weight % acid) is based on the total weight of all α,β ethylenically unsaturated carboxylic acid monomers and ethylene in the base resin. The weight percentage of acid in the base resin is measured by Fourier transform infrared spectroscopy (FTIR analysis) using titration-calibrated standards. The degree of neutralization may be measured by several techniques. For example, infrared analysis may be used to calculate the degree of neutralization from the changes that produce absorption bands. Another method involves titration of a solution of the ionic copolymer with a strong base. Another method involves X-ray fluorescence. All of these methods are within the scope of the art of those skilled in the art.

[0018] The neutralized ethylene acid copolymer may contain copolymer units of ethylene and acrylic acid, methacrylic acid, or both. In embodiments, the neutralized ethylene acid copolymer may contain 70% to 85% by weight, for example, 75 to 85%, 80% to 85%, 70% to 80%, 70% to 75%, 75% to 80%, or any subset thereof of ethylene copolymer units, based on the total polymer weight of the neutralized ethylene acid copolymer, and 15% to 30% by weight, for example, 15% to 25%, 15% to 20%, 20% to 30%, 25% to 30%, 20% to 25%, or any subset thereof of acrylic acid or methacrylic acid copolymer units.

[0019] According to some embodiments, the neutralized ethylene acid copolymer may contain a carboxylic acid group. The carboxylic acid group may be derived from acrylic acid, methacrylic acid, comonomers, or combinations thereof. The carboxylic acid group may be neutralized with one or more metal salts. The cation of the metal salt may be monovalent, divalent, trivalent, or have a higher valency. The metal salt may include alkali metal salts such as sodium (Na) salts, potassium (K) salts, or both; alkaline earth metal salts such as beryllium (Be), zinc (Zn), magnesium (Mg) salts, calcium (Ca) salts, strontium (Sr) salts, barium (Ba) salts, and radium (Ra) salts; cationic salts such as aluminum (Al) salts, chromium (Cr) salts, iron (Fe) salts, lanthanide metal cation salts; or combinations thereof. In embodiments, the metal salt may include sodium salts, magnesium salts, zinc salts, or combinations thereof.

[0020] 0.1% to 100% of the carboxylic acid groups of the neutralized ethylene acid copolymer may be neutralized with a metal salt. In embodiments, 1% to 100%, 5% to 100%, 10% to 100%, 20% to 100%, 40% to 100%, 60% to 100%, 80% to 100%, 0.1% to 80%, 0.1% to 60%, 0.1% to 40%, 0.1% to 20%, 5% to 95%, 10% to 90%, 20% to 80%, 30% to 70%, 30% to 60%, 20% to 40%, or any subset thereof of the carboxylic acid groups of the neutralized ethylene acid copolymer may be neutralized with a metal salt. In one embodiment, 40% to 70% of the carboxylic acid groups of the neutralized ethylene acid copolymer can be neutralized with a sodium cation.

[0021] In light of this disclosure, the neutralization percentage is expressed using the assumption that each cation reacts with the maximum number of carboxylic acid groups calculated from its ionic charge. That is, for example, it is assumed that Al³⁺ reacts with 3 carboxylic acid groups, Mg²⁺ and Zn²⁺ react with 2 each, and Na⁺ reacts with 1. The neutralization level can be calculated by the following equation:

[0022]

number

[0023] In an embodiment, the neutralized ethylene acid copolymer may further contain 1% to 35% by weight of a comonomer based on the total polymer weight of the neutralized ethylene acid copolymer. The comonomer may include carbon monoxide, sulfur dioxide, acrylonitrile, maleic anhydride, maleic acid diester, maleic acid, maleic acid monoester, itaconic acid, fumaric acid, fumaric acid monoester, salts of these acids, glycidyl acrylate, glycidyl methacrylate, and glycidyl vinyl ether, methyl acrylate, ethyl acrylate, isopropyl acrylate, butyl acrylate, pentyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate and butyl methacrylate, pentyl methacrylate, or a combination thereof. In an embodiment, the neutralized ethylene acid copolymer may contain 1% to 30% by weight, 1% to 25% by weight, 1% to 20% by weight, 1% to 15% by weight, 1% to 10% by weight, 1% to 5% by weight, 5% to 35% by weight, 10% to 35% by weight, 15% to 35% by weight, 20% to 35% by weight, 25% to 35% by weight, 30% to 35% by weight, 5% to 30% by weight, 10% to 25% by weight, 15% to 20% by weight, or any subset thereof of the comonomer based on the total polymer weight of the neutralized ethylene acid copolymer.

[0024] The neutralized ethylene acid copolymer may have a melt flow index (I2) of 0.1 g / 10 min to 6 g / 10 min as measured according to ASTM D1238. In an embodiment, the neutralized ethylene acid copolymer may have a melt flow index (I2) of 0.9 g / 10 min to 13 g / 10 min, 0.9 g / 10 min to 10 g / 10 min, 0.9 g / 10 min to 5 g / 10 min, 0.9 g / 10 min to 6 g / 10 min, 1 g / 10 min to 6 g / 10 min, 2 g / 10 min to 10 g / 10 min, 4 g / 10 min to 6 g / 10 min, 0.1 g / 10 min to 5 g / 10 min, 0.1 g / 10 min to 4.75 g / 10 min, or 0.5 g / 10 min to 4.5 g / 10 min, or any subset thereof. The melt flow index (I2) is measured at 190 °C and 2.16 kg according to ASTM D1238.

[0025] The neutralized ethylene acid copolymer may have a density of 0.1 g / cm3 to 2 g / cm3, 0.5 g / cm3 to 1.5 g / cm3, 0.8 g / cm3 to 1.2 g / cm3, 0.9 g / cm3 to 1.1 g / cm3, 0.9 g / cm3 to 1.0 g / cm3, 0.95 g / cm3 to 1.0 g / cm3, 0.96 g / cm3 to 0.98 g / cm3, or any subset thereof. The density is measured according to ASTM D792.

[0026] A neutralized ethylene acid copolymer suitable for use in polymer sheet 104 is available under the trade name SURLYN™ and can be purchased from Dow Inc. (Midland, MI).

[0027] Referring further to FIG. 1, polymer sheet 104 may include at least 50 wt% of a neutralized ethylene acid copolymer. In embodiments, polymer sheet 104 may include at least 60 wt%, at least 75 wt%, at least 90 wt%, at least 95 wt%, at least 99 wt%, or even at least 99.9 wt% of a neutralized ethylene acid copolymer, based on the total weight of polymer sheet 104.

[0028] Polymer sheet 104 may have a thickness of 0.01 mm to 0.51 mm. The thickness of polymer sheet 104 should be selected to have a thickness sufficient to provide impact protection while maintaining a thickness thin enough to ensure optical transparency. In embodiments, polymer sheet 104 may have a thickness of 0.05 mm to 0.51 mm, 0.1 mm to 0.51 mm, 0.15 mm to 0.51 mm, 0.18 mm to 0.51 mm, 0.2 mm to 0.51 mm, or any subset thereof.

[0029] Article 108 may include a polymer sheet 104 having a first surface and a second surface, and a coating 102 in direct contact with at least a portion of the first surface. In embodiments, there may be no additional layers, such as a primer layer, between the polymer sheet 104 and the coating 102. The coating 102 may be an air-contact layer (for example, the coating 102 may be an outer layer on which no further layers are disposed).

[0030] Coating 102 may contain acrylic material. Although not limited to theory, some embodiments of the acrylic material in coating 102 may provide hardness, scratch protection, and moisture protection to the neutralized ethylene acid copolymer material in polymer sheet 104. In embodiments, coating 102 may contain at least 80% by weight, at least 90% by weight, at least 95% by weight, at least 99% by weight, or even at least 99.9% by weight of acrylic material, based on the total weight of coating 102.

[0031] The acrylic material may contain ethyl acrylate (EA) and methyl methacrylate (MMA). In embodiments, the acrylic material may further contain hydroxyl-ethyl methacrylate (HEMA). In embodiments, the acrylic material may further contain itaconic acid. In embodiments, the acrylic material may contain 20% to 80% by weight of ethyl acrylate (EA) based on the total weight of the acrylic material, for example, 20% to 70% by weight, 20% to 60% by weight, 20% to 50% by weight, 20% to 40% by weight, 30% to 80% by weight, 40% to 80% by weight, 50% to 80% by weight, 60% to 80% by weight, 30% to 70% by weight, 40% to 60% by weight, or any subset thereof of ethyl acrylate. In embodiments, the acrylic material may contain 15% to 75% by weight of methyl methacrylate, based on the total weight of the acrylic material, for example, 15% to 65% by weight, 15% to 55% by weight, 15% to 45% by weight, 15% to 35% by weight, 25% to 75% by weight, 35% to 75% by weight, 45% to 75% by weight, 55% to 75% by weight, 25% to 65% by weight, 35% to 55% by weight, or any subset thereof of methyl methacrylate. In embodiments, the acrylic material may include HEMA in the range of 0% to 20% by weight, for example, 0% to 17.5%, 0% to 15%, 0% to 12.5%, 0% to 10%, 0% to 7.5%, 0% to 5%, 0% to 2.5%, 0.1% to 20%, 1% to 20%, 2.5% to 20%, 5% to 20%, 7.5% to 20%, 10% to 20%, 2.5% to 17.5%, 5% to 15%, or any subset thereof, based on the total weight of the acrylic material.In embodiments, the acrylic material may contain 0% to 20% by weight of itaconic acid, based on the total weight of the acrylic material, for example, 0% to 17.5% by weight, 0% to 15% by weight, 0% to 12.5% ​​by weight, 0% to 10% by weight, 0% to 7.5% by weight, 0% to 5% by weight, 0% to 2.5% by weight, 0.1% to 20% by weight, 1% to 20% by weight, 2.5% to 20% by weight, 5% to 20% by weight, 7.5% to 20% by weight, 10% to 20% by weight, 2.5% to 17.5% by weight, 5% to 15% by weight, or any subset thereof of itaconic acid. In embodiments, the acrylic material may contain 0.1% to 10% by weight of HEMA, 15% to 30% by weight of MMA, 15% to 30% by weight of EA, and 0.1% to 10% by weight of itaconic acid.

[0032] The acrylic material may be formed from the reaction product of an acrylic emulsion, such as a self-crosslinking acrylic emulsion. The self-crosslinking acrylic emulsion may be aqueous. The self-crosslinking acrylic emulsion may further contain an adhesion promoter. The adhesion promoter may contain an amino-functional silane, an alkoxysilane, or both. The alkoxysilane may contain a monofunctional, difunctional, trifunctional alkoxysilane, or a combination thereof.

[0033] Acrylic materials may have a glass transition temperature of 10°C to 50°C, for example, 10°C to 40°C, 10°C to 30°C, 10°C to 20°C, 20°C to 50°C, 30°C to 50°C, 40°C to 50°C, 20°C to 40°C, or any subset thereof.

[0034] Suitable commercially available acrylic materials include RHOPLEX® ECO-100, available from Dow Inc. (Midland, Michigan, USA).

[0035] In one or more embodiments, the acrylic material may contain butyl acrylate (BA) and methyl methacrylate (MMA0). In embodiments, the acrylic material may further contain one or more of hydroxyl-ethyl methacrylate (HEMA), styrene, and polyisocyanate. In embodiments, the acrylic material may contain, based on the total weight of the acrylic material, 10% to 80% by weight of butyl acrylate (BA), 15% to 75% by weight of methyl methacrylate (MMA), 0% to 20% by weight of hydroxyl-ethyl methacrylate (HEMA), 0% to 20% by weight of styrene, and 1% to 20% by weight of polyisocyanate. In embodiments, the acrylic material may contain HEMA in the following proportions based on the total weight of the acrylic material: 0% to 15% by weight, 0% to 10% by weight, 0% to 5% by weight, 1% to 20% by weight, 1% to 15% by weight, 1% to 10% by weight, 2.5% to 20% by weight, 2.5% to 10% by weight, 2.5% to 5% by weight, or any subset thereof. In embodiments, the acrylic material may contain BA in the following proportions based on the total weight of the acrylic material: 10% to 70% by weight, 10% to 50% by weight, 10% to 30% by weight, 10% to 20% by weight, 10% to 15% by weight, or any subset thereof. In embodiments, the acrylic material may contain MMA in amounts of 10% to 75% by weight, 10% to 50% by weight, 10% to 30% by weight, 15% to 75% by weight, 15% to 50% by weight, 15% to 30% by weight, 20% to 75% by weight, 20% to 50% by weight, 20% to 30% by weight, 10% to 30% by weight, or any subset thereof. In embodiments, the acrylic material may contain styrene in amounts of 0% to 20% by weight, 0% to 15% by weight, 0% to 10% by weight, 0% to 5% by weight, 1% to 20% by weight, 1% to 10% by weight, 1% to 5% by weight, 1% to 2.5% by weight, or any subset thereof.In embodiments, the acrylic material may contain polyisocyanates in amounts of 1% to 18% by weight, 1% to 15% by weight, 1% to 13% by weight, 1% to 10% by weight, 1% to 7.5% by weight, or 1% to 5% by weight, based on the total weight of the acrylic material. In embodiments, the acrylic material may further contain methacrylic acid, for example, 0% to 10% by weight, 0% to 7.5% by weight, 0% to 5% by weight, 0% to 2.5% by weight, 0.1% to 10% by weight, 0.1% to 5% by weight, 0.1% to 2.5% by weight, 1% to 10% by weight, 1% to 5% by weight, 1% to 2.5% by weight, or any subset thereof. In this embodiment, the acrylic material may contain 0% to 10% by weight of HEMA, 10% to 30% by weight of BA, 10% to 30% by weight of MMA, 0% to 10% by weight of styrene, and 0% to 10% by weight of methacrylic acid.

[0036] Suitable commercially available acrylic materials include RHOSHIELD® 3275, available from Dow Inc. (Midland, Michigan, USA).

[0037] The acrylic material may be applied as a relatively thin film by spray coating, dipping coating, or by placing droplets of the acrylic material onto the surface of the polymer sheet 104. In embodiments, the surface of the polymer sheet 104 may be treated by corona discharge before application of the acrylic material. The disclosed acrylic material has relatively strong adhesion to the neutralized ethylene acid copolymer layer even without corona discharge treatment, but in certain cases, the fixation can be further improved if the neutralized ethylene acid copolymer is corona-treated before coating. Corona treatment in some cases further improves the fixation of the coating 102 to the polymer sheet. Corona treatment can be performed, for example, immediately before coating the polymer sheet 104.

[0038] The coating 102 may have a thickness of 0.2 μm to 20 μm, for example, 0.2 μm to 15 μm, 0.2 μm to 10 μm, 0.2 to 8 μm, 0.2 μm to 6 μm, 1 μm to 20 μm, 1 μm to 15 μm, 1 μm to 10 μm, 1 to 8 μm, 2 μm to 20 μm, 2 μm to 15 μm, 2 μm to 10 μm, 2 μm to 8 μm, 2 μm to 6 μm, or any subset thereof.

[0039] Article 108 may have an equivalent weight of coating 102 of 0.3 grams / square centimeter (gsm) to 32gsm, for example, 0.5gsm to 32gsm, 1gsm to 32gsm, 2gsm to 32gsm, 4gsm to 32gsm, 8gsm to 32gsm, 16gsm to 32gsm, 24gsm to 32gsm, 0.5gsm to 25gsm, 0.5gsm to 20gsm, 0.5gsm to 15gsm, 0.5gsm to 10gsm, 0.5gsm to 5gsm, 2gsm to 25gsm, 4gsm to 20gsm, 6gsm to 15gsm, or any subset thereof.

[0040] As shown in Figure 2, article 108 may include a polymer sheet 104, a coating 102, and an adhesive layer 202. The adhesive layer 202 may be positioned on a second surface of the polymer sheet 104 opposite to the surface of the polymer sheet 104 that is in contact with the coating 102. In some embodiments, article 108 may be bonded to a substrate 106 by the adhesive layer 202. In other embodiments, such as those without a substrate 106, the adhesive layer 202 may be an air-contact layer.

[0041] The adhesive layer 202 may contain a pressure-sensitive adhesive (PSA). The pressure-sensitive adhesive may contain an acrylic PSA. The acrylic PSA may contain one or more acrylate compounds. The one or more acrylate compounds may include one or more of 2-ethylhexyl acrylate (2-EHA), ethyl acrylate, and butyl acrylate (BA). In embodiments, the one or more acrylate compounds may include 2-ethylhexyl acrylate (2-EHA), ethyl acrylate, and butyl acrylate (BA). In embodiments, the acrylic PSA may contain 10% to 80% by weight of 2-ethylhexyl acrylate (2-EHA), 10% to 75% by weight of ethyl acrylate, and 0% to 20% by weight of butyl acrylate (BA), based on the total weight of the acrylic PSA. The adhesive layer 202 may contain at least 80% by weight, for example, at least 90% by weight, at least 95% by weight, at least 99% by weight, or even more than 99.9% by weight of acrylic PSA.

[0042] Article 108 may be transparent. As used herein, a transparent material is a material that allows an observer to clearly see an object on the opposite side. Transparency can be quantified as the clarity of the material and the haze of the material.

[0043] With protective thickness, article 108 may have an average Gardner transparency of at least 80%, as determined by ASTM D1746. In embodiments, with protective thickness, article 108 may have an average Gardner transparency of at least 82%, at least 84%, at least 86%, at least 88%, at least 90%, or at least 92%, as determined by ASTM D1746. Alternatively, transparency may be measured as Zebedee transparency, as determined by ASTM D1746. Article 108 may have an average Zebedee transparency of at least 10%, for example, at least 15%, at least 20%, at least 25%, or at least 28%. The protective thickness may be at least 0.1 mm, for example, at least 0.12 mm, at least 0.14 mm, at least 0.16 mm, at least 0.18 mm, or at least 0.2 mm, 0.01 mm to 3 mm, 0.1 mm to 3 mm, 0.1 mm to 1.5 mm, 0.1 mm to 1 mm, 0.1 mm to 0.5 mm, 0.1 mm to 0.3 mm, 0.2 mm to 0.3 mm, or any subset thereof.

[0044] With protective thickness, article 108 may have a haze of less than 20% as measured by ASTM D1003. In embodiments, with protective thickness, article 108 may have a haze of less than 18%, less than 16%, less than 12%, less than 10%, less than 8%, less than 6%, less than 4%, less than 3%, or even less than 2% as measured by ASTM D1003.

[0045] With protective thickness, article 108 may have a Spencer Dart impact resistance of at least 1500 grams-force (gf) in accordance with ASTM D3420. In embodiments, with protective thickness, article 108 may have a Spencer Dart impact resistance of at least 2000gf, at least 2200gf, at least 2400gf, at least 2800gf, at least 3000gf, at least 3250gf, at least 3500gf, at least 3750gf, at least 4000gf, at least 4250gf, at least 4500gf, at least 4750gf, or at least 5000gf.

[0046] Article 108 may have a hardness of at least 5B, as measured according to ASTM D3363-20. It should be understood that the hardness is measured at the air-contact surface of the coating 102. In embodiments, article 108 may have a hardness of at least 4B, at least 3B, at least 2B, at least B, or at least HB. On the ASTM D3363-20 hardness scale, hardness ranges from 6B (softest) to 9H (hardest).

[0047] Article 108 may mainly comprise a polymer sheet 104 and a coating 102. In embodiments, the polymer sheet 104 and the coating 102 may comprise at least 95% of the thickness of article 108, for example, at least 98%, at least 99%, or even 99.9%. In embodiments, the polymer sheet 104, the coating 102, and the adhesive layer 202 may comprise at least 95% of the thickness of article 108, for example, at least 98%, at least 99%, or even 99.9%.

[0048] In embodiments, the coated substrate 100 and article 108 may lack a primer layer. In embodiments, article 108 may contain a primer layer of less than 1% by weight, for example, less than 0.5% by weight, less than 0.1% by weight, less than 0.01% by weight, or even less than 0.001% by weight. The primer layer may contain an epoxy material. While not limited to theory, it is thought that the primer layer may reduce the transparency of article 108.

[0049] Each layer of article 108 may be produced by any preferred method known to those skilled in the art or not yet discovered, so the method of producing article 108 is not particularly limited. For example, according to embodiments, the individual layers and article 108 may be produced by casting, extrusion, co-extrusion, lamination, and / or similar, including orientation (either uniaxial or biaxial) by various methodologies (e.g., inflation film, mechanical stretching, or similar).

[0050] The substrate 106 may include glass. In some embodiments, the substrate 106 may be a cover glass for an electronic device. Test method

[0051] Hayes

[0052] Measure the haze according to ASTM D1003.

[0053] Gardner Transparency

[0054] Gardner clarity is measured according to ASTM D1746.

[0055] Zebedee Transparency

[0056] Zebedee transparency is determined according to ASTM D1746.

[0057] Meltflow Index (I2)

[0058] The melt flow index I2 is measured at 190°C and 2.16 kg according to ASTM D1238.

[0059] density

[0060] The density is measured according to ASTM D792.

[0061] Spencer Dart Impact

[0062] The impact resistance of the Spencer Dart is measured according to ASTM D3420.

[0063] hardness

[0064] The hardness is measured according to ASTM D3363-20.

[0065] glass transition temperature

[0066] The glass transition temperature is measured according to ASTM D3418. manner

[0067] According to the first aspect, the article is a polymer sheet comprising a first surface and a second surface opposite to the first surface, wherein the polymer sheet comprises a neutralized ethylene acid copolymer material containing carboxylic acid groups, and the carboxylic acid groups of the ethylene acid copolymer are at least partially neutralized with metal ions, The present invention may include a coating in direct contact with at least a portion of the first surface of a polymer sheet, wherein the coating comprises an acrylic material and is an air-contact layer.

[0068] In addition to the first embodiment, according to the second embodiment, the combination of polymer sheet and coating may comprise at least 95% of the thickness of the article.

[0069] In conjunction with the first or second embodiment, according to the third embodiment, the polymer sheet may have a thickness measured as the distance between the first surface and the second surface, and the thickness may be 0.01 mm to 0.51 mm.

[0070] In combination with any one of embodiments 1 to 3, according to the fourth embodiment, the ratio of the surface area of ​​the first surface to the thickness of the article may be at least 100,000 mm.

[0071] In combination with any one of embodiments 1 to 4, according to the fifth embodiment, the coating may have a thickness of 2 μm to 8 μm.

[0072] In conjunction with any one of embodiments 1 to 5, according to the sixth embodiment, the article may further include an adhesive layer in direct contact with the second surface of the polymer sheet.

[0073] In combination with any one of embodiments 1 to 6, according to embodiment 7, the neutralized ethylene acid copolymer material may contain 1% to 35% by weight of a comonomer comprising carbon monoxide, sulfur dioxide, acrylonitrile, maleic anhydride, maleic acid diester, maleic acid, maleic acid monoester, itaconic acid, fumaric acid, fumaric acid monoester, salts of these acids, glycidyl acrylate, glycidyl methacrylate, and glycidyl vinyl ether, methyl acrylate, ethyl acrylate, isopropyl acrylate, butyl acrylate, pentyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate, pentyl methacrylate, or a combination thereof.

[0074] In conjunction with any one of embodiments 1 to 7, according to the eighth embodiment, the neutralized ethylene acid copolymer material may be an ethylene methacrylic acid copolymer, and the methacrylic acid groups of the copolymer are at least partially neutralized with sodium ions.

[0075] In combination with any one of embodiments 1 to 8, according to embodiment 9, the neutralized ethylene acid copolymer material may contain 15% to 30% by weight of copolymer units of acrylic acid or methacrylic acid and 70% to 85% by weight of copolymer units of ethylene, based on the total weight of the neutralized acid copolymer, wherein about 40% to about 70% of the carboxylic acid groups of the neutralized acid copolymer are neutralized as carboxylate salts containing sodium cations.

[0076] In combination with any one of embodiments 1 to 9, according to the tenth embodiment, the neutralized ethylene acid copolymer material may have a melt flow index (I2) of 0.9 g / 10 min to 13 g / 10 min, as measured by ASTM D1238.

[0077] In combination with any one of embodiments 1 to 10, according to the eleventh embodiment, the acrylic material may contain, based on the total weight of the acrylic material, 20% to 80% by weight of ethyl acrylate (EA), 15% to 75% by weight of methyl methacrylate (MMA), 0% to 20% by weight of hydroxyl-ethyl methacrylate (HEMA), and 0% to 20% by weight of itaconic acid.

[0078] In combination with any one of embodiments 1 to 11, according to the twelfth embodiment, the acrylic material may contain, based on the total weight of the acrylic material, 10% to 80% by weight of butyl acrylate (BA), 15% to 75% by weight of methyl methacrylate (MMA), 0% to 20% by weight of hydroxyl-ethyl methacrylate (HEMA), 0% to 20% by weight of styrene, and 1% to 20% by weight of polyisocyanate.

[0079] In combination with any one of embodiments 1 to 12, according to the 13th embodiment, the article may be a screen protector.

[0080] According to the 14th embodiment, the coated substrate may also include an article comprising a transparent substrate, a polymer sheet positioned on at least a portion of a first surface of the substrate and comprising a first surface and a second surface opposite to the first surface, wherein the polymer sheet comprises a neutralized ethylene acid copolymer material containing carboxylic acid groups, the carboxylic acid groups of the ethylene acid copolymer being at least partially neutralized with metal ions, and a coating in direct contact with at least a portion of the first surface of the polymer sheet, wherein the coating comprises an acrylic material and the coating is an air-contact layer.

[0081] In conjunction with embodiment 14, according to embodiment 15, the substrate may include glass. [Examples]

[0082] The following embodiments are provided to illustrate the embodiments described herein and are not intended to limit the scope of the herein or any appended claims.

[0083] material

[0084] PS-1 is a neutralized ethylene acid copolymer as described herein, having a melt flow rate of 4.5 g / 10 min (ASTM D1238) (190°C / 2.16 kg) and a density of 0.970 g / cc (ASTM D792). The production of PS-1 is described in U.S. Patent No. 3,264,272, which is incorporated herein by reference in its entirety.

[0085] PS-2 is a neutralized ethylene acid copolymer as described herein, having a melt flow rate of 1.8 g / 10 min (ASTM D1238) (190°C / 2.16 kg) and a density of 0.950 g / cc (ASTM D792). The production of PS-2 is described in U.S. Patent No. 3,264,272, which is incorporated herein by reference in its entirety.

[0086] PS-3 is a neutralized ethylene acid copolymer described herein, having a melt flow rate of 0.7 g / 10 min (ASTM D1238) (190°C / 2.16 kg) and a density of 0.970 g / cc (ASTM D792). PS-3 is a highly branched neutralized ethylene acid copolymer produced by random free radical polymerization. The production of PS-3 is described in U.S. Patent No. 3,264,272, which is incorporated herein by reference in its entirety.

[0087] PS-4 is a neutralized ethylene acid copolymer described herein, having a melt flow rate of 4.5 g / 10 min (ASTM D1238) (190°C / 2.16 kg) and a density of 0.970 g / cc (ASTM D792). The production of PS-4 is described in U.S. Patent No. 3,264,272, which is incorporated herein by reference in its entirety.

[0088] Coating 1 is an acrylic material formed from an aqueous acrylic latex with a solids content of 42% and a hydroxyl equivalent of 2600, as supplied. Upon curing, the acrylic material of Coating 1 contains, based on the total weight of the acrylic material, 10% to 80% by weight of butyl acrylate (BA), 15% to 75% by weight of methyl methacrylate (MMA), 0% to 20% by weight of hydroxyl-ethyl methacrylate (HEMA), and 0% to 20% by weight of styrene.

[0089] Coating 2 is an acrylic material formed from a self-crosslinking aqueous emulsion. Upon curing, the acrylic material of Coating 2 contains, based on the total weight of the acrylic material, 20% to 80% by weight of ethyl acrylate (EA), 15% to 75% by weight of methyl methacrylate (MMA), 0% to 20% by weight of hydroxyl-ethyl methacrylate (HEMA), and 0% to 20% by weight of itaconic acid.

[0090] CR 9-101 is an isocyanate coreactant commercially available from Dow Inc. (Midland, MI).

[0091] In the following examples, various coated and uncoated polymer sheets were prepared. Sheets with a thickness of 1 mil to 7 mil were manufactured by cast extrusion, and sheets with a thickness of 8 mil to 10 mil were manufactured by compression molding. The presence or absence of coating is shown in the table below.

[0092] Example 1

[0093] Each film was tested for Gardner clarity (ASTM D1746), haze (ASTM D1003), and impact resistance (ASTM D3420). 92-gauge polyethylene terephthalate (PET) was included as a comparison. The results are shown in Table 1.

[0094] [Table 1]

[0095] As can be seen from Table 1, polymer sheets PS-1 to PS-4 generally exhibit improved haze, Gardner clarity, and impact resistance compared to PET sheets.

[0096] Example 2

[0097] Four polymer sheets of four grades of neutralized ethylene acid copolymer material (PS-1 to PS-4) and a comparative sheet of polyethylene terephthalate (PET) were coated with acrylic material. The polymer sheets were manufactured using a compression molding process. The resin was placed in a heated, open mold cavity, and then the mold was closed under pressure (using a hydraulic press) to allow the material to flow and completely fill the cavity. After that, the pressure was maintained until the material solidified.

[0098] The polymer sheets PS-1, PS-2, PS-3, and PS-4 had a thickness of 0.2 mm.

[0099] Polymer sheets were coated with acrylic material. Polymer sheets PS-1 to PS-4 were treated with corona discharge before coating. PET film was not treated with corona discharge in the first experimental setup. Specifically, the polymer sheets were coated with Coating 1, Coating 2, and Coating 1 / CR 9-101 (mixture ratio of 100:7) using the Meyer rod drawdown coating method. After coating the polymer sheets by wet coating, the samples were placed in a 70°C oven for 3 minutes to remove volatile substances. The coating weight of the dried coatings was measured as 3.6 lb / ream for Coating 1 / CR 9-101 and 2.98 lb / ream (3000 square feet) for Coating 2. The dried samples were removed from the oven, allowed to reach room temperature, and cured at 77°F and 50% relative humidity before testing.

[0100] The hardness of the samples was measured using the ASTM D3363-20 test method with pencils, and the results are shown in Table 2. Pencil hardness ranges from 6B (softest) to 5B, 5B, 3B, 2B, B, HB, F, H, 2H, 3H, 4H, 5H, 6H, 7H, 8H, and 9H (hardest).

[0101] [Table 2]

[0102] As can be seen from Table 2, the best results regarding hardness were obtained with PS-1 and PS-4 coated with either Coating 1 / CR 9-101 or Coating 2.

[0103] Coated and uncoated PS-1 samples were tested for haze, clarity, dart, and abrasion. Comparative examples were also prepared using 92ga PET. The PS-1 samples had a standard thickness of 8 mil (0.232 mm). The PET samples had a standard thickness of 1 mil (0.0254 mm). Thickness T1 is the thickness measured for haze, Gardner clarity, and dart. Thickness T2 is the thickness measured for Zebedee clarity and Taber abrasion.

[0104] The results are shown in Table 3.

[0105] [Table 3]

[0106] Haze was measured using the ASTM D1003 Standard Test Method for Haze and Luminous Transmittance of Transparent Plastics. As can be seen from Table 3, coating 2 had the least effect on haze on the PS-4 film and further reduced the haze on the PET film. On the other hand, samples coated with coating 1 showed a 2.7 to 3.5 times increase in haze compared to uncoated samples. In all cases, the haze of the PET samples was higher than the haze of PS-1.

[0107] Transparency was measured using the ASTM D1746-Standard Test Method for Transparency of Plastic Sheeting, employing Gardner and Zebedee metering. This test method covers the measurement of transparency of plastic sheets in terms of normal transmittance. As can be seen from Table 3, the transparency results from the Gardner and Zebedee metering are consistent with the results from haze, where coating 2 improved the transparency of the PET film, maintained or slightly improved the transparency of the PS-4 film, and coating 1 / CR 9-101 reduced transparency by 3.5–4.3%.

[0108] In addition to optical properties, two mechanical properties most important for this application were measured: impact resistance and abrasion resistance. Impact resistance was measured using the ASTM D3420 method, "Pendulum Impact Resistance of Plastic Film," and abrasion resistance was measured using the ASTM D4060 method, "Abrasion resistance of Organic Coatings by Taber Abraser." As can be seen from Table 3, polymer sheets containing neutralized ethylene acid copolymer material exhibited the best abrasion and impact resistance.

[0109] While specific embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, the appended claims are intended to encompass all such changes and modifications that fall within the scope of the invention.

Claims

1. A polymer sheet comprising a first surface and a second surface opposite the first surface, wherein the polymer sheet comprises a neutralized ethylene acid copolymer material containing carboxylic acid groups, and the carboxylic acid groups of the ethylene acid copolymer are at least partially neutralized with metal ions, An article comprising a coating in direct contact with at least a portion of the first surface of the polymer sheet, wherein the coating comprises an acrylic material and the coating is an air-contact layer.

2. The article according to claim 1, wherein the combination of the polymer sheet and the coating comprises at least 95% of the thickness of the article.

3. The article according to claim 1 or 2, wherein the polymer sheet has a thickness measured as the distance between the first surface and the second surface, and the thickness is between 0.01 mm and 0.51 mm.

4. The article according to claim 3, wherein the ratio of the surface area of ​​the first surface to the thickness of the article is at least 100,000 mm.

5. The article according to any one of claims 1 to 4, wherein the coating has a thickness of 2 μm to 8 μm.

6. The article according to any one of claims 1 to 5, further comprising an adhesive layer in direct contact with the second surface of the polymer sheet.

7. The article according to any one of claims 1 to 6, wherein the neutralized ethylene acid copolymer material contains 1% to 35% by weight of a comonomer comprising carbon monoxide, sulfur dioxide, acrylonitrile, maleic anhydride, maleic acid diester, maleic acid, maleic acid monoester, itaconic acid, fumaric acid, fumaric acid monoester, salts of these acids, glycidyl acrylate, glycidyl methacrylate, and glycidyl vinyl ether, methyl acrylate, ethyl acrylate, isopropyl acrylate, butyl acrylate, pentyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate, pentyl methacrylate, or a combination thereof.

8. The article according to any one of claims 1 to 7, wherein the neutralized ethylene acid copolymer material is an ethylene methacrylic acid copolymer, and the methacrylic acid groups of the copolymer are at least partially neutralized with sodium ions.

9. The article according to any one of claims 1 to 8, wherein the neutralized ethylene acid copolymer material comprises 15% to 30% by weight of copolymer units of acrylic acid or methacrylic acid and 70% to 85% by weight of copolymer units of ethylene, based on the total weight of the neutralized acid copolymer, and about 40% to about 70% of the carboxylic acid groups of the neutralized acid copolymer are neutralized as carboxylate salts containing sodium cations.

10. The article according to any one of claims 1 to 9, wherein the neutralized ethylene acid copolymer material has a melt flow index (I2) of 0.9 g / 10 min to 13 g / 10 min as measured by ASTM D1238.

11. The article according to any one of claims 1 to 10, wherein the acrylic material comprises, based on the total weight of the acrylic material, 20% to 80% by weight of ethyl acrylate (EA), 15% to 75% by weight of methyl methacrylate (MMA), 0% to 20% by weight of hydroxyl-ethyl methacrylate (HEMA), and 0% to 20% by weight of itaconic acid.

12. The article according to any one of claims 1 to 11, wherein the acrylic material comprises, based on the total weight of the acrylic material, 10% to 80% by weight of butyl acrylate (BA), 15% to 75% by weight of methyl methacrylate (MMA), 0% to 20% by weight of hydroxyl-ethyl methacrylate (HEMA), 0% to 20% by weight of styrene, and 1% to 20% by weight of polyisocyanate.

13. The article according to any one of claims 1 to 12, wherein the article is a screen protector.

14. A transparent substrate and An article positioned on at least a portion of the first surface of the substrate, A polymer sheet comprising a first surface and a second surface opposite to the first surface, wherein the polymer sheet comprises a neutralized ethylene acid copolymer material containing carboxylic acid groups, and the carboxylic acid groups of the ethylene acid copolymer are at least partially neutralized with metal ions, and A coated substrate comprising an article comprising a coating in direct contact with at least a portion of the first surface of the polymer sheet, wherein the coating comprises an acrylic material and the coating is an air-contact layer.

15. The coated substrate according to claim 14, wherein the substrate includes glass.

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