EP2528750A1 - Article with erasable writing surface and use thereof - Google Patents

Abstract

Erasable articles with textured writing surfaces and methods for making and using same.

Description

ARTICLE WITH ERASABLE WRITING SURFACE

AND USE THEREOF

Field

This invention relates to articles having an erasable writing surface, e.g., dry erase articles, labels, sheets of writing media, etc., and methods of making and using such articles.

Background

Writing material refers to materials that provide surfaces on which people use appropriate writing instruments, e.g., pencils, pens, markers, etc., to inscribe writing or written matter through deposit of marking material, e.g., pencil led, ink, etc. on the writing surface. Illustrative examples include sheets of paper, sometimes in multilayer form such as adhesive-backed labels, as well as dry erase articles, folders with tabs, etc.

A typical concern with writing materials is that they exhibit effective writability with compatible writing instruments and can be used neatly, including, if desired, exhibiting resistance to smudging, erasability, and reusability.

For instance, dry erase boards typically have hard and smooth surfaces. Smooth dry erase boards are easier to erase than rough dry erase boards. However, smooth dry erase boards have several drawbacks. Such boards are typically glossy or shiny and thus do not work well as a projection screen as is desired in some embodiments. Dry erase writing can be easily smeared or erased unintentionally by a hand or clothing rubbing against the board.

It is desirable to have a dry erase board with low gloss. It is also desired to have a dry erase board with projection capability equal to a commercially available projection screen. In some cases, a dry erase board with smear resistant capability is desired to avoid accidental erasure of the writing or to avoid getting dry erase ink on hands or clothing.

Paper, in sheet and pad form, has been used for many decades as a writing material, either as stand alone media or incorporated into, e.g., adhesive-backed label form. For some applications, however, improved writability, erasability, smudge resistance, etc. are desired.

Paper, matte film, labels, tabs, folders, binders, pockets, calendars and the like typically accept writing from such writing instruments as permanent markers, pens, and pencils. Of such writing instruments, only written matter from pencil is commonly considered to be erasable, and that is dependent in part upon the nature of the writing material and the pencil. It is desirable to have a paper, matte film, label, folder, or pocket that is writable with most writing instruments while at the same time being erasable with a pencil eraser. In addition, it is desirable to have paper, film, label, folder, or pocket with a structured surface that prevents the indicia from being smeared by accidental or deliberate contact with fingers.

Summary

The present invention provides novel erasable articles having writing surfaces with novel characteristics, methods for making such articles, and methods of using such articles.

In brief summary, the writing surface of an erasable article of the invention has a writing surface with a textured front surface as described herein.

The surface structures of the writing surface are characterized by an Rz value as measured by a WYKO optical interferometer. Rz is the average of the 10 highest peak-to- valley values within the measurement area.

In some embodiments, the article of the invention is a dry erase article. When Rz is greater than about 1 um, the gloss of the dry erase article is reduced. When Rz is greater than about 10 um, the dry erase article can be used as a projection screen. When Rz is greater than about 15 um, the dry erase article is resistant to smear of dry erase ink by casual contact. In certain embodiments, in particular those with higher Rz values, the dry erase article is preferably erased with a synthetic fiber dry eraser or a 3M™ Whiteboard Eraser as conventional felt erasers may not perform as well as desired. In addition, dry erase articles of the invention typically exhibit an Ra of about 0.25, sometimes at least about 0.70, and sometimes at least about 1.0, where Ra is the average roughness value within the measurement area.

The present invention provides writing surfaces having surface structures or features on erasable articles that solve one or more of the problems with dry erase boards, paper, films, labels, tabs, folders, pockets, and the like. Writing surfaces having surface structures can be generated over a range of roughness from low roughness to high roughness can be fabricated for desired applications in accordance with the invention. For instance, at a low value of roughness, the gloss of the board is reduced. At a higher value of roughness, the dry erase article can effectively double as a projection screen. At a still higher value of roughness, the dry erase article provides resistance of dry erase ink writing to smearing by casual contact while continuing to perform effectively as a projection screen. For writable and erasable articles such as paper, films, labels, tabs, folders, pockets and the like, at all values of roughness, the article of the invention is erasable with a pencil eraser. For higher values of roughness, the erasable article provides resistance of most writing to smearing by casual and deliberate contact.

In one aspect, this invention comprises surface structures on a dry erase article and a method for making the surface structures. The surface structures are defined by an Rz value as measured by a WYKO optical interferometer. Rz is the average of the 10 highest peak-to-valley values within the measurement. When Rz is greater than about 1 um, the gloss of the dry erase article is reduced. When Rz is greater than about 10 um, the dry erase article typically also exhibits optical properties suitable for use as a projection screen. When Rz is greater than about 15 um, the dry erase article is resistant to smear of dry erase ink by casual contact.

In certain embodiments, in particular those with higher Rz values, the dry erase article is preferably erased with a synthetic fiber dry eraser or a 3M™ Whiteboard Eraser as conventional felt erasers may no perform as well as desired.

In addition, dry erase articles of the invention typically exhibit an Ra of about 0.25, sometimes at least about 0.70, and sometimes at least about 1.0.

In another aspect, the invention provides a method for making such dry erase articles which includes providing a coated substrate, the coated substrate comprising a first coatable material applied to a substrate, the coatable material forming a first major surface of the coated substrate; means for changing the viscosity of the first coatable material from a first viscosity to a second viscosity; a face-side roller having an outer surface positioned to contact the first major surface of the coated substrate to impart a matte finish thereon; means for hardening the first coatable material; and optionally additives to the coatable material that reduce the surface energy of the coated and cured substrate.

In brief summary, a method of the invention comprises the steps of (1) providing a coated substrate comprising a curable coatable material disposed on a substrate, the curable coatable material providing a first major surface of the coated substrate; (2) changing the viscosity of the curable coatable material from the initial viscosity to a second viscosity; (3) contacting the first major surface of the coated substrate with at least one face-side roller to impart a matte finish; and (4) hardening or curing the curable coatable material to provide the film.

Dry erase articles can provide many advantageous benefits. In many instances it is desirable to resist accidentally erasing portions of the content as you write (e.g., writer's sleeve or palm smears existing writing), interact with (e.g., gesture or point at the board), walk past (e.g., accidentally brush by), or purposely edit content on the dry erase surface. In the editing situation, a smear resistant board affords more control to erase only the desired portions. Also, due to the robust nature of the hardcoat, dry erase articles of the invention are more abrasion and scuff resistant than are many previously available alternative dry erase materials.

Briefly summarizing, the method of using such articles comprises: (1) providing a writing member of the invention; (2) writing first written matter on the writing surface using a writing instrument; and (3) erasing at least a portion of the first written matter.

Conventional writing surfaces include paper, film, labels, folders, pockets and the like. In many cases it is desirable that these surfaces be writable with most markers, pens, and pencils and also be erasable with a pencil eraser. An erasable writing surface can be erased and reused rather than being discarded after a single use. As an added benefit, the invention provides a conventional writing surface with smear resistance to accidental or deliberate contact with hands.

Brief Description of Drawing

The invention is further explained with reference to the drawing wherein:

Fig. 1 is a cross-sectional schematic of an illustrative embodiment of the invention; Fig. 2 is a schematic view of a system for making a writing member according to an embodiment of the invention; and

Fig. 3 is a schematic view of a portion of a system for making a writing member according to an embodiment of the invention.

These figures are not to scale and are intended to be merely illustrative and not limiting. Detailed Description of Illustrative Embodiments

For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification.

The term "polymer" will be understood to include polymers, copolymers (e.g., polymers formed using two or more different monomers), oligomers and combinations thereof, as well as polymers, oligomers, or copolymers that can be formed in a miscible blend by, for example, coextrusion or reaction, including transesterification. Both block and random copolymers are included, unless indicated otherwise.

Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings of the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviations found in their respective testing measurements.

Weight percent, percent by weight, % by weight, and the like are synonyms that refer to the concentration of a substance as the weight of that substance divided by the weight of the composition and multiplied by 100.

The recitation of numerical ranges by endpoints includes all numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the content clearly dictates otherwise. Thus, for example, reference to a composition containing "a compound" includes a mixture of two or more compounds. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise.

As used herein, Ra refers to a measure of average surface roughness and Rz refers to a measure of the average of the 10 highest peak-to-valley distances within an area of about 0.5 mm x 0.6 mm unit measurement with an optical interferometer. Ra is discussed in ASME B46.1-1995, ISO 4287-1997, and ISO 4287/1-1997. Rz is discussed in ASME B46.1-1995 and ISO 4287-1997.

Erasable Article Construction

An erasable article of the invention is shown in Fig. 1 wherein article 10 comprising writing member 12 and optional backing member 14 is shown. In accordance with the present invention, front face 16 of writing member 12, i.e., the writing surface, has structured features in accordance with the invention. As desired, writing surface 16 is characterized by such properties as good writing receptivity, erasability, and resistance to smudging. In some embodiments, backing member 14 comprises structural member 18 and optional primer layer 20 to achieve desired interply adhesion to writing member 12. In some embodiments, article 10 may further comprise optional adhesive 22 on its back side, e.g., shown here on the back side of backing member 14, adhesive 22 providing means to adhere article 10 to an adherend as desired. In some embodiments, article 10 may further comprise frame member 24 on one or more edge portions to secure the component members of article 10 together, facilitate handling of article 10, provide means of attaching article 10 to a supporting surface, etc.

Acceptance of an inscribing with a compatible writing instrument is referred to as writability. For instance, use of a pencil to write on paper.

An advantage of articles of the invention is that they exhibit superior erasability to compatible writing instruments, i.e., they can be inscribed with writing, and then the writing or a portion thereof can be easily and cleanly removed when desired, perhaps replaced by alternative writing if desired.

Articles of the invention can be made in a variety of embodiments as desired, illustrative examples including, individual or padded sheets, e.g., similar to paper, films, adhesive-back labels, incorporated into folders, notebook covers, dry erase articles, etc. Dry Erase Article

In some embodiments, articles of the invention are used as dry erase articles.

Acceptance of ink on writing surface 16 as written indicia without beading of the ink can be defined as the "wettability" of the dry erase writing surface. Wettability refers to a writing line that can retain its shape and continuity as the solvent dries. Dewetting of the solvent causes the line to move in or break at certain points, causing voids in the writing. Acceptable wettability (or writing without dewetting) is typically accomplished if the surface energy of the writing surface is greater than the surface tension of the solvents in the marker inks. On some matte dry erase films, dewetting of dry erase markers can be hard to detect by the naked eye. Sometimes the dewetting occurs between the peaks or high roughness areas on the film. This "microscopic" dewetting can be observed under a microscope.

The writing surface additionally provides a level of "erasability" which allows the user to wipe away (e.g. with a dry cloth or dry eraser) indicia written with a dry erase marker once it is no longer desired. Low surface energy components may be added to the writing surface in order to improve the erasability as long as the writing surface accepts dry erase writing without macroscopic or microscopic dewetting. Reducing the surface energy is thought to prevent tenacious adhesive of the binders and other solids in the marker inks to the writing surface.

The present invention provides a dry erase article with reduced gloss, ability to project on the surface, resistance to smear of dry erase writing, and convenient erase on demand performance. The dry erase article accepts ink from all dry erase markers and in some embodiments is erasable by standard dry erasers, a 3M SCOTCH-BRITE™ High Performance Cleaning Cloth, or by the 3M™ Whiteboard Eraser. In the case of embodiments with higher Rz, it has been found that a higher performance eraser such as a 3M SCOTCH-BRITE™ High Performance Cleaning Cloth or 3M™ Whiteboard Eraser should be used. Dry erase articles of the invention can also be cleaned with commercially available dry erase cleaners if desired.

Optional backing 14 is selected to impart desired performance, e.g., color background to the writing surface, reflective properties in the case of dry erase articles with improved projection capability, transmission properties in the case of a dry erase overlay, etc. In some embodiments, the dry erase article comprises a coating 12 on a substrate 14 with an adhesive coated on the second side of 14 and a release liner on the back of the adhesive.

In some embodiments, the dry erase article is a substrate with a coating on one side and an adhesive on the other side, in which the article is laminated to a second substrate which is then framed to make a dry erase board.

Writing Member

The advantages of the present invention are obtained by providing surface texture to the front face of the writing member in accordance with the invention.

Typically, the writing surface of articles of the invention will have an Rz value of at least 1 micron. In some embodiments it is preferable to have an Rz value of around 10 um. In other embodiments, it is preferable to have an Rz value of 15 um or greater.

It has been observed that when the Rz value is at least about 1 micron that the surface gloss of the resultant article is reduced sufficiently that the board scatters light from ambient light sources such as windows, room lights, etc. thereby reducing glare and leaving the writing thereon easily read.

In instances when the dry erase article is to also be used as a projection screen, Rz is preferably greater than about 10 microns. Projection screens generally have a 60° gloss value of less than 30. Preferably, a projection screen has a 60° gloss value of less than 20.

The present invention provides for a dry erase article with a 60° gloss value of less than 20. Reduction of gloss value is desirable for reduction of so-called hot spots, improving the legibility of information written or, in the case of projection embodiments, projected on the dry erase article.

When Rz is greater than about 15 microns, the dry erase article is resistant to smear of dry erase ink by casual contact. Information can be easily lost from a conventional dry erase article when the writing is accidentally erased by contact with a hand or with clothing. The present invention provides for surface structures on the dry erase article that are large enough to protect the writing from accidental erasing. With such embodiments it is typically preferred to use high performance erasing devices, e.g., a 3M SCOTCH-

BRITE™ High Performance Cleaning Cloth, or by the 3M™ Whiteboard Eraser, rather than conventional felt erasers. Such embodiments can also be cleaned with commercially available dry erase cleaners or window cleaners.

In addition, dry erase articles of the invention typically exhibit an Ra of about 0.25, sometimes at least about 0.70, and sometimes at least about 1.0.

In some embodiments, the coatable material of the instant invention is a mixture of one or more monomers, oligomers and/or polymers and radiation cure initiators. In other embodiments, the coatable material includes the foregoing oligomer(s), monomer(s) and/or polymer(s) along with a volume of nanoparticles. In still other embodiments, the coatable material includes the foregoing oligomer(s), monomer(s) and/or polymer(s) along with the optional ingredients of nanoparticles, solvents, and a monomer, oligomer, or polymer capable of reducing the surface energy of the coated and cured article.

In one embodiment, the coating formulation may include one or more monomers, oligomers, or polymers capable of reducing the surface energy of the cured formulation. It is understood that the term low surface energy monomer refers to one or more monomers, oligomers, or polymers capable of reducing the surface energy of the cured formulation.

In some embodiments, the low surface energy monomer may be chosen from the group of fluorocarbon, silicone, or hydrocarbon containing monomers, oligomers, or polymers. The amount of the monomer, oligomer, or polymer is chosen to reduce the surface energy of the cured coating without causing dewetting or beading up of any dry erase marker on the dry erase article. In one embodiment, the amount of monomer, oligomer, or polymer is chosen to reduce the surface energy of the cured coating without causing dewetting of alcohol or ketone based dry erase markers.

In one embodiment, reduction of surface energy of the writing surface is achieved by the addition of monomers, oligomers, or polymers that tend to migrate to the surface of the coating formulation. In addition to the improved low gloss and anti-smear

performance discussed above, in such embodiments of the invention the dry erase article also can exhibit reduced ghosting of dry erase markers and resistance to staining, e.g., by permanent markers.

The low surface energy monomer, oligomer, or polymer may be chosen from the group of fluorocarbon, silicone, or hydrocarbon monomers. Fluorocarbon monomers suitable for the invention include but are not limited to per fluoro acrylates or

methacrylates, C₄F₉ based sulfonamide acrylates and C₃F₇ based sulfonamide acrylates. Example fluorocarbon monomers include C₄F9S0₂N(CH₃)C₂H₄0- CONHC₆H₅CH₂C6H₅NHCO-OC₂H₄0COCH=CH₂ also known as MeFBSE-MDI-HEA, C4F9S02N(CH3)C2H40-CONH(CH₂)eNHCO-OC2H40COCMe=CH₂,

C₄F₉S0₂N(CH₃)C₂H₄0-CONH(CH₂)₆NHCO-OCi₂H₂₄0COCH=CH₂, and CF₃CH₂0- CONH C₆H₅CH₂C6H₅NHCO-OC₂H₄0COCH=CH₂. Perfiuoroacrylates suitable for the invention include Ci to C₆ perfluoroalkyl acrylates or the type

RS0₂NMeC₂H₄OC(0)CH=CH₂, where R is C_nF₂„₊i and n is an integer from 1 to 6.

Another family of suitable fluorochemical monomers are described in US Patent Nos. 7,279,210 (Hulteen et al.) and 7,199,197 (Caldwell et al). These fluoroacrylate monomers are represented by the formula:

O O O

II II II

C_nF_2n+i X— OCNH— A— HNCO (C_pH_2p) OCC = CH₂

R'

wherein: n is an integer in a range of from 1 to 6, inclusive, O R O

II I II

X is S— NC_mH_2m- , CNC_mH_2m- ,

O H

Rf

I

C— OC_yH_2y— , OC_qH_2q— , or C_qH_2q— ,

H wherein: R is H or an alkyl group having 1 to 4 carbon atoms; m is an integer in a range of from 2 to 8, inclusive; R_f is C_nF2_n+1; y is an integer in a range of from 0 to 6, inclusive; q is an integer in a range of from 1 to 8, inclusive; and A is a hydrocarbylene group; p is an integer in a range of from 2 to 30, inclusive; and R' is H, CH₃, or F.

In some embodiments, A is selected from the group consisting of -C₆ H₁₂-,

Other fluorochemical additives suitable for the invention include perfluoropolyether urethane acrylates described in US Patent No. 7,173,778 (Jing et al). Fluorochemical oligomers suitable for the invention include FC-4430 and FC-4432 from 3M Company, St. Paul, MN. Fluorochemical polymers suitable for the invention include perfluoropolyether polymers with poly(alkylene oxide) repeat units described in PCT Application No. WO2009/076389 (Yang et al).

Silicone monomers suitable for the invention include but are not limited to silicone acrylate monomers. Exemplary silicone acrylate monomers include BYK-371 Reactive Silicone Surface Additive, BYK-373 Reactive Silicone Surface Additive. BYK-377 Reactive Silicone Surface Additive, BYK-UV 3500 Surface Additives for Radiation Curable Systems, BYK-UV 3530 Surface Additives for Radiation Curable Systems, BYK- UV 3570 Surface Additives for Radiation Curable Systems. BYK SILCLEAN™ 3710 Surface Additives to Improve Surface Cleanability from BYK-Chemie GmBH, Wesel, Germany. Other suitable silicone monomers include TEGORAD™ 2100, TEGORAD™ 2200N, TEGORAD™ 2250, and TEGORAD™ 2300 silicone acrylate monomers from Evonik Goldschmidt Corporation, Hopewell, VA.

Hydrocarbon monomers can be used to reduce the surface energy of a coating.

Those hydrocarbon monomers are typically characterized by a long side chain that can form a crystalline structure on a surface. Suitable hydrocarbon monomers include but are not limited to octadecyl acrylate.

In some embodiments, the radiation curable material includes the foregoing oligomer(s), monomer(s) and/or polymer(s) in one or more solvents along with a volume of optional particles or nanoparticles, e.g., to impart increased hardness and durability to the writing member.

Nanoparticles can be surface modified which refers to the fact that the

nanoparticles have a modified surface so that the nanoparticles provide a stable dispersion. "Stable dispersion" refers to a dispersion in which the colloidal nanoparticles do not agglomerate after standing for a period of time, such as about 24 hours, under ambient conditions, e.g., room temperature (about 20 to about 22°C), and atmospheric pressure, without extreme electromagnetic forces.

Surface-modified colloidal nanoparticles can optionally be present in a polymer coating used as a coatable composition herein with nanoparticles present in an amount effective to enhance the durability of the finished element. The surface-modified colloidal nanoparticles described herein can have a variety of desirable attributes, including, for example, nanoparticle compatibility with a coatable composition such that the

nanoparticles form stable dispersions within the coatable composition, reactivity of the nanoparticle with the coatable composition making the composite more durable, and a low impact or uncured composition viscosity. A combination of surface modifications can be used to manipulate the uncured and cured properties of the composition. Surface-modified nanoparticles can improve optical and physical properties of the coatable composition such as, for example, improved resin mechanical strength, minimized viscosity changes while increasing solids volume loading in the coatable composition and maintain optical clarity while increasing solid volume loading in the coatable composition.

In some embodiments, the nanoparticles are surface-modified nanoparticles.

Suitable surface-modified colloidal nanoparticles can comprise oxide particles.

Nanoparticles may comprise a range of particle sizes over a known particle size

distribution for a given material. In some embodiments, the average particle size may be within a range from about 1 nm to about 100 nm. Particle sizes and particle size distributions may be determined in a known manner including, for example, by

transmission electron microscopy (TEM). Suitable nanoparticles can comprise any of a variety of materials such as metal oxides selected from alumina, tin oxide, antimony oxide, silica, zirconia, titania and combinations of two or more of the foregoing. Surface- modified colloidal nanoparticles can be substantially fully condensed.

In some embodiments, silica nanoparticles can have a particle size ranging from about 5 to about 100 nm. In some embodiments, silica nanoparticles can have a particle size ranging from about 10 to about 30 nm. Silica nanoparticles can be present in the coatable composition in an amount from about 10 to about 100 phr. In some embodiments, silica nanoparticles can be present in the coatable composition in an amount from about 25 to about 90 phr. Silica nanoparticles suitable for use in the coatable compositions of the present invention are commercially available from Nalco Chemical Co. (Naperville, IL) under the product designation NALCO™ Colloidal Silicas. Suitable silica products include NALCO™ products 1040, 1042, 1050, 1060, 2327 and 2329. Suitable fumed silica products include for example, products sold under the trade name AEROSIL series OX-50, -130, -150, and -200 from DeGussa AG, (Hanau, Germany), and CAB-O-

SPERSE™ 2095, CAB-O-SPERSE™ A105, CAB-O-SIL™ MS available from Cabot Corp. (Tuscola, IL) Surface-treating the nanosized particles can provide a stable dispersion in the coatable composition (e.g., a polymeric resin). Preferably, the surface- treatment stabilizes the nanoparticles so that the particles will be well dispersed in the coatable composition and results in a substantially homogeneous composition.

Furthermore, the nanoparticles can be modified over at least a portion of its surface with a surface treatment agent so that the stabilized particle can copolymerize or react with the coatable composition during curing.

Silica nanoparticles can be treated with a surface treatment agent. Surface treatment agents suitable for particles to be included in the coatable composition include compounds such as, for example, isooctyl trimethoxy-silane, N-(3- riethoxysilylpropyl)methoxyethoxyethoxyethyl carbamate (PEG3TES), SILQUEST™ A1230, N-(3-triethoxysilylpropyl) methoxyethoxyethoxy ethyl carbamate (PEG2TES), 3- (methacryloyloxy) propyltrimethoxysilane, 3-acryloxypropyl trimethoxysilane, 3- (methacryloyloxy) propyltriethoxysilane, 3-(methacryloyloxy) propylmethyl

dimethoxysilane, 3-(acryloyloxypropyl) methyldimethoxysilane, 3-(methacryloyloxy) propyldimethylethoxysilane, 3-(methacryloyloxy) propyldimethylethoxysilane, vinyldimethyl ethoxysilane, phenyltrimethoxysilane, n-octyltrimethoxysilane,

dodecyltrimethoxysilane, octadecyltrimethoxysilane, propyltrimethoxysilane,

hexyltrimethoxysilane, vinylmethyl diacetoxysilane, vinylmethyldiethoxysilane, vinyltriacetoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane,

vinyltrimethoxysilane, vinyltriphenoxysilane, vinyltri-t-butoxysilane, vinyltris- isobutoxysilane, vinyltriisopropenoxysilane, vinyltris(2-methoxyethoxy)silane, styrylethyltrimethoxysilane, mercaptopropyltrimethoxysilane, 3 -glycidoxypropyl trimethoxysilane, acrylic acid, methacrylic acid, oleic acid, stearic acid, dodecanoic acid, 2- [2-(2-methoxyethoxy)ethoxy] acetic acid (MEEAA), beta-carboxyethylacrylate, 2-(2- methoxyethoxy)acetic acid, methoxyphenyl acetic acid, and mixtures of two or more of the foregoing.

In some embodiments, the average particle sizes (e.g., particle diameter) may be within the range from about 1 nm to about 1000 nm . In addition to the foregoing particle sizes, use of smaller and larger average particle sizes are also contemplated. In embodiments of the invention, at least a portion of the foregoing particles may be surface modified in the manner described above. In other embodiments, all of the particles are surface modified. In still other embodiments, none of the particles are surface modified. As will be understood, coating compositions used to make writing members of the invention may include optional additives to enhance or control characteristics as desired, e.g., rheology modifiers (e.g., JAYLINK™ Rheology Modifiers), colorants (e.g., dyes and/or pigments), fire retardants, antioxidants, stabilizers, antiozonants, plasticizers, UV absorbers, hindered amine light stabilizers (HALS), etc.

Backing Member

In some embodiments, e.g., where the writing member is not sufficiently self supporting or where other properties are desired of the erasable article, e.g., imparted with magnetic properties, curl resistance properties, tear resistance properties, dimensional stability, color, etc., the dry erase article will further comprise a backing member on the opposite side of the writing member from the front or writing surface thereof, e.g., adhered on the rear surface of the writing member. Depending upon the embodiment, the backing member may be single or multilayer.

Suitable substrates for this coating include but are no limited to glass, , , paper, coated paper, paper film laminates, polymeric films, polymeric sheets, metallic foils, metallic sheets, porcelain sheets, etc. Polymeric films and sheets may include but are not limited to polyester, polypropylene, polyethylene, polystyrene, cellulose acetate, cellulose triacetate, polycarbonate, and polyvinyl chloride. Polymeric films and sheets may include copolymers, blends, or coextruded multilayer films of the aforementioned polymers or other polymers. If desired, the backing member may include or even consist of an adhesive on the rear surface thereof to facilitate bonding of the resultant dry erase article to a substrate or surface.

In embodiments where the good projection performance is desired of the erasable article, e.g., as a multipurpose dry erase article, the writing member can be preferably be substantially clear and the backing member will have reflective characteristics. For example, the projection member disclosed in U.S. Patent Appln. No. 12/684,565, filed December 15, 2009, could be used in dry erase articles of the invention.

An important attribute of a backing member is a good bond between the backing member and the writing member. In order to insure a good bond, the substrate may have to be primed or surface treated before application of the coating formulation. Suitable primers include with one or more chemicals known in the art such as acrylic polymers, melamine polymers, urethane polymers, and vinyl chloride containing polymers. Surface treatments include but are not limited to corona, plasma, flame, or flash lamp treatment.

If desired, the backing may be opaque and/or colored to impart desired appearance to the resultant erasable article. Also, decorative or organizational graphics, headings, etc. may be provided in the article so as to be visible to viewers, e.g., legends embedded within the writing member, on the rear surface of the writing member, on the front surface of the backing, etc. with desired decorative emblems, information headings (e.g., "NAME", "IN", "OUT", and so forth). The smear resistance and controlled erasure properties which can be attained with some embodiments of the invention makes such dry erase articles of the invention well suited for use in high motion, high traffic settings, e.g., in team rooms, on sports sidelines, etc. where information written on the article is likely to be subjected to inadvertent scuffing and erasure. In addition, the smear resistance and controlled erasability properties of dry erase articles of the invention makes them well suited for instances where some of the written material is to be left for long term and then removed and other portions of the written material being erased and revised in the short term. Dry erase articles of the invention can be applied as overlays to underlying graphic material, e.g., posters, calendars, process maps, etc.

Method of Making Writing Member

A system and method for making matte finish films that can be used to make writing members of dry erase articles of the invention is provided in US Patent Appln. Publn. No. 2009/0029054 (Yapel et al.) which is incorporated herein by reference in its entirety.

As dispensed onto a substrate, the radiation curable coatable material has a first or initial viscosity and is in contact with the surface of the substrate, the opposite surface of the coatable material forming a first major surface of the coated substrate. Means are provided for changing the viscosity of the coatable material from the first or initial viscosity to a second viscosity. In some embodiments, the means for changing the viscosity comprises a means for increasing the viscosity of the coatable material from a first lower viscosity (e.g., as a liquid, paste or gel-like material) to a second higher viscosity (e.g., a partially cured, thickened, somewhat hardened solid). In other

embodiments, means for changing the viscosity of the coatable material comprises means for decreasing the viscosity of the coatable material from a first higher viscosity to a second lower viscosity. These means typically include evaporation of a solvent and chilling the substrate to increase viscosity and heating the substrate to reduce viscosity.

In the system of FIG. 2, the coated substrate is conveyed over idler rollers to a second station, where the coated substrate is subjected to conditions to change the viscosity by increasing the viscosity of the coatable material from an initial or first viscosity to a second viscosity, the second viscosity being greater than the initial viscosity. In embodiments of the invention, the coatable material, when first applied to the substrate, is typically liquid or gel-like and is flowable or spreadable so as to form a liquid or gel- like film of material on a major surface of the substrate.

In some embodiments, the coatable material includes at least one solvent and the coatable material is applied directly to the substrate. In other embodiments, the coatable material may be solventless (e.g., 100% solids) and the coatable material may be applied to a roller and then transferred to the substrate 31.

Second station 34 provides means for changing the viscosity of the coatable material. In the depicted embodiment, the means for changing the viscosity is a means for increasing the viscosity of the coatable material. In embodiments in which the coatable material includes at least one solvent, means for increasing the viscosity of the coatable material may be provided in the form of a heat source such as an oven, a heating element or the like wherein the coatable material is subjected to elevated temperatures sufficient to drive off solvent and/or partially cure at least one component in the coatable material. While in the second station 34, the viscosity of the coatable material is raised to a second or higher viscosity to render the coatable material sufficiently hardened, dried and/or cured to endure further processing, as is described herein. The exact temperature of the second station 34 will depend, in part, on the composition of the coatable material, the desired viscosity of the coatable material after it exits the second station 34 and the amount of time a coated substrate dwells within the station 34.

The coatable material is a polymerizable material in which the polymerization reaction is initiated by the application of electromagnetic radiation. In those embodiments, means for increasing the viscosity of the coatable material may comprise a source of electromagnetic radiation, i.e., ultraviolet (UV) radiation, infrared (IR) radiation, x-rays, gamma-rays, visible light or the like. In some embodiments, the means for increasing the viscosity of the coatable material comprises an electron beam (e-beam) source and the coatable material is curable or otherwise hardens when exposed to an e-beam. In embodiments of the invention wherein the means for changing the viscosity of the coatable material involves temperature control for heating or cooling of the coatable material from a first viscosity to a second viscosity, various mechanisms are contemplated. In some embodiments, the means for changing the viscosity of the coatable material is a temperature-controlled chamber or oven through which the coated substrate passes to adjust the viscosity of the coatable material. In other embodiments, the means for changing the viscosity of the coatable material comprises a temperature-controlled roll that contacts the coated substrate 30 as it advances through the system 27. In some

embodiments, means for changing the viscosity of the coatable material comprises a plurality of temperature-controlled rollers. In other embodiments, means for changing the viscosity of the coatable material may comprise a source of temperature-controlled gas. In still other embodiments, means for changing the viscosity of the first coatable material comprises temperature-controlled liquid.

In some embodiments, the coatable material is applied to the substrate as a solventless (e.g., 100% solids) composition that may be hardened by cooling. Moreover, the coatable material may initially be heated to reduce its initial viscosity and thereby facilitate the initial application of the coatable material onto the substrate 31. Thereafter, the coated substrate 30 may be cooled to increase the viscosity of the coatable material.

Referring again to the system 27 of FIG. 2, coated substrate 30 is conveyed from second station 34 to third station 36 where the second major surface of the coatable material directly contacts one or more face-side rollers 38. In the embodiment shown in FIG. 2, face-side rollers comprise three rollers 38a, 38b, 38c. It will be understood that fewer face-side rollers (e.g., less than three) or additional face-side rollers (e.g., four or more) may be included within the third station 36. Coated substrate 30 is maintained in sufficient tension around face-side rollers 38 to generate a matte finish on the second major surface of the coatable material, as is further described herein.

In achieving a matte finish, the coatable material will be at a second viscosity at which the coatable material is not as easy to deform when pressed against face-side rollers 38 as it was when coatable material was first dispensed by the extrusion die 28. In the appropriate environment (e.g., light, electromagnetic radiation, temperature, humidity, etc.), the coatable material will not be excessively hardened to the point that no finish can be imparted to the second major surface of the precursor by face-side rollers 38. As is shown in FIG. 2, the face-side roller 38 is positioned in a manner that facilitates contact between the face-side roller and the major surface of the coated substrate.

In some embodiments, the face-side rollers 38 may be heated so that the coatable material is also heated as it contacts the roller 38. In other embodiments, face-side rollers 38 may be chilled or cooled so that the coatable material is also chilled or cooled as it contacts the surface of the rollers 38.

Not wishing to be bound to any particular theory, it is believed that a matte finish is imparted to the second major surface by the interaction of the second major surface of the coatable material and the unremarkable surface of the face-side rollers, whereby the coatable material is of sufficient tack that a portion of the precursor material adheres to the surface of the face-side roller. At this point in the process, the coatable material has been subjected to conditions at the second station 34 so that the precursor is cohesive and resistant to flow and will not excessively transfer to the surface of face-side roller 38 or deform when pressed against the face-side roller. However, the outermost layer of the second major surface of the coatable material, adhere to the face-side roller, and then release therefrom to create a surface topography sufficient to impart a matte finish that can be viewed in detail under magnification.

Again, not wishing to be bound by any theory, in some embodiments, a small volume of coatable material may initially adhere to a face-side roller 38. A steady- state condition is typically achieved as coatable material is continually released from the face- side roller 38 at nearly the same rate at which coatable material is picked up by the face- side roller. In other words, an incoming segment of the coated substrate 30 includes coatable material that contacts a face-side roller that has been pre -wetted with the same coatable material from an upstream segment of the coated substrate. As the segment of coatable material contacts the face-side roller, it picks up some of the coatable material already deposited on the roller. As the same segment of coated substrate departs the face- side roll, a portion of the surface layer of the coatable material on the coated substrate splits away so that some of the coatable material remains on the face-side roller while a net amount of coatable material remaining on the substrate is, on average, equal to the amount of the coatable material incoming to the face-side roll. As described in US Patent Appln. Publn. No. 2009/0029054, other combinations of face-side rollers are also contemplated. In another embodiment, a face-side roller may be brought into contact with the second surface of the coatable material using a nip arrangement as shown in FIG. 3, for example. In this embodiment, face-side roller 338 is paired with a backing roller 346. The face-side roller contacts the second surface of the coatable material on coated substrate 322 which is carried on backing roller 346. The coated substrate 322 is conveyed between the face-side roller 338 and the backing roller 346 with the backing roller capable of being moved relative to the face-side roller 346 to thereby move the second surface of the coatable material on coated substrate 322 into contact with face side roller 338 as well as to adjust the force at which the second surface is held against the face-side roller 338. In the embodiment of FIG. 4, actuator 348 is provided to control the placement of the coated substrate 322 with respect to the face-side roller 338. Actuator 348 can be of any appropriate design including without limitation pneumatic, hydraulic, piezoelectric, electromechanical and the like. In this manner, pressure is exerted on the face-side roller 338 through the actuator 348 in a controlled manner.

In other embodiments, the dry coating formulation on the substrate is passed over two rollers, the first roller acting to remove any dust or particles from the coating and the second roll to provide a roughened surface suitable for polymerization by radiation curing. The use of the first roller is particularly useful for improving the robustness of the structuring process in low cleanliness environments because debris particles fall onto a coated substrate during transport through the web-line to the structuring roller nip and become entrained on the roll, disrupt the coating, and create a repeating area of nonuniform structure. For example, particles can also include fibers such as PET fibers, cellulose fibers, and cotton fibers, etc. The first roller, i.e., a "Decoy Roll (DR)" is used to collect and remove defect causing debris and particles from a liquid coating. The DR removes debris from the liquid coating that would otherwise be captured on the final second structuring roller without adversely affecting the final structured coating produced. The DR does not need to have the same quality finish or even be fabricated of the same material as the final second structuring roller. In a preferred embodiment, the DR has equal or higher affinity for the particulates than the final structuring roller. Multiple DRs enable greater capture efficiency and uninterrupted debris removal via sequential disengagement and cleaning of the decoy rolls (DRs). The distance from the DR to the final structuring roller can vary based on the cleanliness of the manufacturing environment and process line layout.

In one embodiment, monomers, oligomers, or polymers are added to the coating formulation in order to reduce the surface energy of the cured coating on the substrate. In some embodiments the surface energy reduction material preferentially migrates to the surface of the coating composition and is cured in place. While not wishing to be bound by any theory, it is believed that passing the coating composition over the roller imparting a matte finish causes a further redistribution of the low energy monomer. That is, some of the low energy monomer on the surface of the coating is mixed back into the bulk of the coating. This means that the matte surface may have a lower surface concentration of the low energy monomer after passing over the roller that imparts a matte pattern.

Redistribution of low surface energy materials enables the use of low surface energy monomers, oligomers, and polymers that do not homo-polymerize at the surface of a coating. Illustrative examples of such materials include silicone acrylate monomers.

The process of the invention provides a matte finish without slavishly reproducing the surface features of the face-side roller, and the process of the invention is not a conventional embossing process. Comparisons made during a microscopic examination of the surfaces of the face-side rollers and the resulting matte finish on the second major surface of the coatable material demonstrate that the face-side roller surfaces and the resulting matte finish are not mirror images of one another.

The coated substrate 30 exits the third station 36 with a matte surface finish imparted to the surface thereof by the face-side rollers 38. Means for further hardening the coatable material are provided in the form of an optional fourth station 40 where the coated substrate 30 is exposed to conditions to harden or cure the coatable material. The fourth station 40 is optional in that the coatable material may not require such a treatment.

In the system 27 shown in FIG. 2, the fourth station 40 includes a source 42 which may be a heat source or a source of electromagnetic radiation such as ultraviolet (UV) or infrared (IR) radiation, visible light, x-rays, gamma-rays, e-beam or the like. In some embodiments, the fourth station is an oven capable of thermally curing the coatable material. In other embodiments, the fourth station is a radiation source capable of initiating a curing reaction within the coatable material. In still other embodiments, the fourth station 40 may comprise a combination of heat and radiation curing, optionally with forced air drying or other features known to those skilled in the art. In still other embodiments, the fourth station may comprise a plurality of individual stations or a plurality of sources similar or analogous to the source 42. In some embodiments, fourth station 40 may be configured to apply the same type of treatment applied by second station 34 (e.g., heating or cooling). An optional deflector or shield 44 deflects heat or radiation emitted from the source 42 and directs it toward the coatable material on the coated substrate 30.

In some embodiments, means for hardening the coatable composition comprises exposure to ambient conditions while, for example, a free radical polymerization process within the coatable material runs to completion.

Following hardening, the coated substrate 30 may be conveyed to another station (not shown) such as a cutting station to cut the continuous coated substrate into smaller discrete sections. Alternatively, the coated substrate may be directed to a wind-up station where the continuous coated substrate is wound up on a take-up roll, for example. Other process stations (e.g., a packaging station) may be included in the system 27, depending on the use of the final article.

Optionally, the cured coating on the substrate may be subjected to a second cure or post cure of the same or different nature as the first cure.

In one embodiment, the present invention comprises a UV curable coating composition. This coating composition may contain one or more solvents. The coating composition is applied to a substrate by a suitable coating method such as die coating or gravure coating. A suitable substrate is a polyester film. After coating the substrate is passed through an oven to remove the solvent and increase the viscosity of the coating formulation. After the oven, the substrate contacts a rubber roller, with the dried coating formulation in direct contact with the roller. As the formulation leaves contact with the roller, a rough or matte finish is imparted to the coating composition. The roughened coating formulation is polymerized by radiation shortly after the roller to lock in the surface structures.

In one embodiment, the surface structures reduce the gloss of the dry erase article.

When coating on a smooth white film, the 60° gloss is less than 80. In another embodiment, the surface structures reduce the 60° gloss of the dry erase article to 30 or less. These articles are useful as a projection screen.

In another embodiment, the surface structures provide resistance of dry erase ink to smear by accidental contact. In this embodiment, the surface structures have an Rz value of 15 μιη or greater.

Methods of Use

As mentioned above, the invention also encompasses a method of using writing articles as disclosed herein comprising: (1) providing a writing member of the invention; (2) writing first written matter on the writing surface using a writing instrument; and (3) erasing at least a portion of the first written matter.

Articles of the invention can be made in a variety of forms including stand along writing articles, sheet form in individual (i.e., single sheet) or padded form, file folders, dividers, folios, pockets, and sleeves, notebooks, notebook dividers, labels, etc.

Articles of the invention can be adapted to be used with a variety of writing instruments including but not limited to pencils, pens (e.g., ball-point, fountain, or felt tip), markers (e.g.., dry erase and permanent markers), and highlighters.

Examples

The invention will be further explained with the following illustrative, non-limiting examples.

Test methods Gloss: Gloss is measured at 60 degrees according to ASTM D 2467, Standard Test

Method for Specular Gloss of Plastic Films and Solid Plastics using a BYK-Gardner gloss meter.

Topography: The surface topography was measured with a WYKO® NT3300™ optical interferometer (VEECO Instruments, Plainview, NY) operated in VSI mode using a lOx objective with a field-of-view of 1.0, and a 2% modulation threshold. The backscan and length were both set to 10 microns and varied as necessary to obtain the most complete dataset of surface information. The data were visualized and corrected using Vision for Profilers version 3.44 software by Veeco Instruments. The instrument scanned an area of 460 x 600 μιη. In addition to providing a two dimensional map of the surface in false colors to indicate height, the instrument calculates Ra (average roughness) and Rz (average of the ten highest peak to valley measurements in the measurement area). The values reported represent the average of the roughness parameters measured at five randomly chosen sites on each sample.

The sample was coated with a gold/palladium film before surface measurements were recorded (6x current 30 mA, 30 s in SEM lab) to prevent sub-surface reflectivity.

Dewetting of Dry Erase Markers: Dry erase surfaces were marked with 14 different markers comprising 7 brands of dry erase markers. The dry erase markers were AVERY® MARKS-A-LOT® (Avery-Dennison, Pasadena, CA), BEIFA™ private label markers (Beifa, Tokyo, Japan), BIC® Dry Erase markers (BIC Corporation, Milford, CT), DIXON™ Dry Erase Markers (Dixon Ticonderoga Co., Heathrow, FL), EXPO® Bold (Sanford Corp., Bellwood , IL), EXPO® 2 (Sanford Corp.), and QUARTET® Markers (Acco, Inc, Lincolnshire, IL). All of the markers had a chisel point. Two colors of marker from each brand were chosen, one black and the other red, green, or blue. For each marker brand, a horizontal space about 2.5 cm high on the sample surface was reserved for that marker brand. The first marker was used to write the marker brand name on the left hand side of the 2.5 cm high space and the second marker was used to write the same marker brand name on the right hand side of the 2.5 cm high space. In this manner, all the writing from each marker brand is lined up in one erasable horizontal line.

After marking the surface of the dry erase article, each line of writing was examined for evidence of dewetting by the appearance of holes in the writing or a shrinkage of the characteristic writing line. If macroscopic dewetting was not observed, then the writing was observed under a microscope for dewetting. The effect of

microscopic dewetting is to make the writing line look light. The total number of markers that have evidence of dewetting was calculated. Because there are 14 different markers in the writing test, the range of possible dewetting scores is 0 to 14. For example, if no markers dewet, the dewetting score is zero. If 10 markers dewet, the dewetting score is 10. Smear resistance of Dry Erase Surfaces: The following brands of black dry erase markers were used for smear resistance: AVERY® MARKS- A-LOT®, BIC® Bold Markers, DIXON™ Dry Erase, EXPO® Bold, EXPO® Low Odor, and QUARTET® Dry Erase Markers. A 4 inch long vertical line was written on each film with each marker. After at least one minute of dry time, a standard 2.54 x 7.62 cm glass microscope slide was used to scrape the writing along the surface. The slide was held at an angle of 135° away from the line. The edge of the slide was then moved across the line without adding additional hand pressure. The percent of the dry erase ink remaining on the film after scraping with the microscope slide was visually estimated. After each test, the edge of the microscope slide was cleaned with a paper towel. The average percent maker ink remaining was calculated after all markers were tested on the film.

Smear Testing and Erasability of Erasable Labels: The following writing instruments were used for smear and erasability testing of labels - SHARPIE®

Permanent Marker Black, POST-IT® Flag Permanent Marker Black, PILOT® V Ball Pen, SHARPIE® Fine Felt Tip Pen Blue, and POST-IT® Ball Point Pen Black. Smear testing was performed by rubbing the written surface to 20 passes with one sheet of 20 lb paper attached to a 2.5 kg weight. Drying times of 10 seconds, 5 minutes and 20 hours were evaluated. The percent of writing remaining after smearing was visually estimated.

Erasability of Erasable Labels: For erasability testing, a 3M™ White Board eraser and a SANFORD™ Magic Rub Eraser 1954 were used. With the 3M™ White Board eraser, the surfaces were erased and the amount of material removed was recorded. For the pencil eraser test, the number of rubs with a SANFORD™ Magic Rub Eraser 1954 needed to fully erase the writing was recorded.

Materials

Materials utilized in the examples and comparatives are shown in Table 1. Table 1. Materials

Examples

Preparation of Functionalized Nano-silica: A 12 liter flask was charged with 3000 g of aqueous colloidal silica solution (NALCO™ 2327 from Nalco) with stirring. To this, 3591 g of l-Methoxy-2-propanol ( DOWANOL™ PM from Dow Chemical) was added. In a separate container, 189.1 g of 3-methacryloxypropyl trimethoxy silane (SILQUEST™ A- 174) was mixed with 455 g of l-methoxy-2-propanol. This pre-mix solution was added to the flask, rinsing with 455 g of l-methoxy-2-propanol. The mixture was heated to 80°C for about 16 hours. The mixture was then cooled to 35°C and vacuum distillation (30 to 35 Torr, 35 to 40°C) with a collection flask. An additional 1813.5 g of l-methoxy-2- propanol was added to the reaction flask part way through the distillation. A total of 6784 g of distillate was collected. After diluting with 250 g of l-methoxy-2-propanol, the final % solids was approximately 48.2%. The mixture was collected by filtering through cheesecloth to remove particulate debris.

HFPO-UA preparation: HFPO-UA refers to hexafluoropropylene oxide urethane acrylate monomer made internally by 3M Company. The HFPO-UA synthesis and composition is described in US Patent No. 7,173,778. The structure is shown below:

Example 1 - Satin finish dry erase article: The coating formulation for this example was made according 25% solids according to the formulation in Table 3.

preparation of the functionalized nano-silica is described in the Examples section.

Table 2. Composition of Example 1 coating formulation

The coater for this example consisted of an unwind station for the substrate, a die coating station, an air flotation oven, a rubber roll capable of contacting the coated side of the substrate, a UV curing station purged under nitrogen, and a wind up station. Die coating was used to apply the formulation to 3 mil thick white polyester film. After coating, the film was dried in a 9 m long air flotation oven set at 54°C. The dry coating on the film was in the form of a viscous liquid. After the oven, the film was passed over a smooth rubber roll with the dry coating in contact with the roll. The rubber roll imparted a matte finish to the dried coating composition. Approximately 30 cm after the rubber roll, the film was passed through a UV cure station and cured with an H bulb. The UV cure station was purged with nitrogen. The line speed on the coater was 15.2 meter per minute. The dry thickness of the coating on the film was 2.0 μιη.

Example 2 - Protectable dry erase article: 3M 906 hardcoat was diluted to 25% solids with ethyl acetate. In addition, hexafluoro propylene oxide urethane acrylate monomer (HFPO-UA) was added to the formulation at a concentration of 0.18% to solids. The final formulation was coated on 3 mil (76 micron) white polyester film, dried, and cured on a coater by the method in Example 1. The dry coating thickness of the formulation on the film was 2.0 μιη.

Example 3 - Smear resistant dry erase article: 3M 906 hardcoat was diluted to 25% solids with ethyl acetate. In addition, hexafluoro propylene oxide urethane acrylate monomer (HFPO-UA) was added to the formulation at a concentration of 0.18% to solids. The final formulation was coated on 3 mil (76 micron) white polyester film, dried, and cured on a coater by the method in Example 1. The dry coating thickness of the formulation on the film was 4.0 μιη. Example 4 - Smear resistant erasable paper: 3M 906 hardcoat with SR 351LV was diluted to 50% solids with ethyl acetate. The formulation was coated on BOISE™

ADVANTEDGE™ CIS clay coated paper, dried, and cured on a coater by the method in Example 1. The dry coating thickness of the formulation was 4.0 μιη. Comparative Example CI : The formulation of Example 1 was coated, dried, and cured on the coater according to the procedure in Example 1 except that the dry coating did not contact a rubber roll prior to the UV curing station. The dry thickness of the coating on the film was 2 μιη. This film was smooth and glossy. Comparative Example C2: This comparative example is the LABEL ONCE™

Erasable Binder Labels, 1" X 3.4" (product number 47929) from Label Once Corporation, Abilene, TX. Comparative Example C3 : This comparative example is an AVERY™ Erasable Label (product number #5429), from Avery Corporation, Brea, CA.

Comparative Example C4: This comparative example is an AVERY™ Durable Write-On Plastic Divider (product number #16170). The product is described as write, erase and reuse.

Dry Erase Article Results

Test results of the Examples 1-3 and Comparative Example CI are shown in Table 3. Some markers dewet on CI but not on Examples 1-3.

Table 3.

Smear Testing of Erasable Film and Paper: Results of smear testing for erasable labels are listed in Table 4. The smear resistant film and paper of Examples 3 and 4 exhibited the least amount of smearing compared to the other materials. This was demonstrated by the smear resistance with the SHARPIE™ permanent marker, where the all of the Comparative Examples materials smeared after 5 minutes. The only pen that had any smearing with material of Examples 3 and 4 after 5 minutes was the SHARPIE® blue felt tip pen, which did not significantly smear after 20 hours.

Erasability Testing of Erasable Film and Paper: Erasability testing with the 3M™ White Board Eraser is shown in Table 5. When using the 3M White Board eraser, the erasability was superior with the materials of Examples 3 and 4 than the materials from the Comparative Examples. The films of Examples 3 and 4 did not ghost or dent from the tip of the writing instrument, unlike the other materials. With the pencil eraser, all of the inks were erasable (Table 6). The erasability was similar for the materials of Examples 3 and 4 and Comparative Examples C2 and C3, however, the film was still indented from writing with the pens. In general, the materials of Examples 3 and 4 were easier to erase than that of Comparative Example C4.

The smear and erasability testing show that overall the smear resistant paper and film of Examples 3 and 4 exhibit superior smear resistance and erasability properties as compared to the Comparative Example materials.

Table 4: Smear testing at various dry times.

Values in the table are the percent of the original writing remaining after rubbing the surface with a paper sheet.

Table 5: Erasability testing with a 3M™ White Board eraser.

Values in the table are the ercent of the writin removed b the eraser.

Table 6: Erasability testing with and a pencil eraser.

Values in the table are the number of rubs with a encil eraser re uired to remove all of the writin .

Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.

The complete disclosure of all patents, patent documents, and publications cited herein are incorporated be reference. The foregoing detailed description and examples have been given for clarity of understanding only. No unnecessary limitations are to be understood therefrom. The invention is not limited to the exact details shown and described, for variations obvious to one skilled in the art will be included within the invention defined by the claims.

Claims

What is claimed is:

1. An article comprising a writing member having a first major surface, wherein said first major surface is a writing surface having a matte finish and having an Rz value of at least about 1 micron.

2. The article of claim 1 wherein said writing surface comprises a coating formed from a radiation curable coating to which a matte pattern was imparted by passing the dry curable coating into contact with a roll and separating from said roll; followed by a radiation cure step that produces a hard matte coating on the writing member.

3. The article of claim 1 wherein said article is a dry erase article.

4. The article of claim 1 further comprising a backing member disposed on the opposite side of said writing member as said writing surface.

5. The article of claim 3 in wherein said writing surface has a 60° gloss of less than 90.

6. The article of claim 3 wherein said Rz value is at least about 10 microns.

7. The article of claim 5 wherein said writing surface has a 60° gloss of less than 30.

8. The dry erase article of claim 1 wherein said Rz value is greater than about 20 microns.

9. The article of claim 8 in wherein said writing surface is resistant to smear by casual contact with hands or clothing.

10. The article of claim 7 in wherein said writing surface has a 60° gloss of less than 20.

11. The article of claim 1 wherein said article is in single sheet or pad form.

12. The article of claim 1 wherien said article is a file folder, adhesive backed label, or tab.

13. The article of claim 1 further comprising an mounting adhesive.

14. The article of claim 1 further comprising one or more frame members.

15. The article of claim 1 wherein said article is a writing surface comprising a paper, matte film, adhesive backed label, tab, folder, binder, pocket, or calendar.

16. The article of claim 1 further comprising written matter on a portion of said writing surface.

17. The article of claim 16 wherein said written matter is erasable with a pencil eraser.

18. The article of claim 16 wherein said written matter was inscribed with a writing instrument selected from the group consisting of ball point pens, felt tip pens, roller ball pens, pencils, permanent markers, dry erase markers, and highlighters.

19. The article of claim 1 wherein said article is writable with ball point pens, felt tip pens, roller ball pens, pencils, permanent markers, dry erase markers, and highlighters.

20. The writable and erasable article of claim 10 wherein said writing surface is resistant to smear by rubbing written material thereon with uncoated paper.

21. A method comprising:

a) providing a writing member of claim 1 ;

b) writing first written matter on said writing surface using a writing instrument; and c) erasing at least a portion of said first written matter.

22. The method of claim 20 wherein said writing is done by hand.

23. The method of claim 10 wherein said writing instrument is selected from the group consisting of pencils, pens, and markers.