JP5936552B2 - Low ghost generation dry erase article and use thereof - Google Patents

Description

  The present invention relates to a dry erase article having good write acceptance for dry erase ink, and easy removal of the dry erase ink even though the time between writing and erasing is long, and the use of such articles.

  Dry erase boards have been used as a writing surface for many years because of their convenience and versatility. These boards provide a means of expression that eliminates blackboard smudges and hassles.

  A dry erase marker written on a dry erase board must form a thick and reliable line without producing water droplets. If dry erase ink produces water droplets on the writing surface, it leaves a dashed or missing point in the resulting written image. A dry erase board is desired in which the dry erase ink does not produce water droplets.

  There are many dry erase articles on the market. Examples of writing surfaces for such articles include enamel, melamine, painted metal, glass, and UV cured acrylate coatings. These surfaces can provide effective wetting of many commercially available dry erase markers as well as sufficient erasability when erased within a short period of time, such as hours, after being written on the top surface. However, if left on the board for days or weeks, the writing cannot be easily erased using the eraser. As a result, traces of writing, sometimes referred to as “ghosting”, remain and need to be removed with a special liquid cleaner.

  There is a need for a dry erase writing surface that provides both good write acceptability and good low ghosting characteristics.

  The present invention provides good write acceptability when written on the top surface, i.e. good dry erasure marker ink wetting and easy removal of dry erasure markings by dry erasing even though the time between writing and erasing is long. A dry erase article is provided that is responsive, ie, has low ghosting. Also, a combination of dry erase performance and ease of use that has not been achieved so far, in some embodiments, provides a method of use to achieve the new high performance dry erase marker.

In summary, the dry erase article of the present invention includes having a writing surface that exhibits both good write acceptability and good ghosting resistance. The dry erase articles of the present invention have a writing surface with a wetting tension of less than about 38 mJ / m ² , typically less than about 32 mJ / m ² , and in some embodiments from about 20 to about 30 mJ / m ^2. Have. Such wetting tension properties are lower than the writing surface of known commercial dry erase articles believed to have a wetting tension of at least about 38 mJ / m ² or greater.

  The desired surface properties can be achieved by coating the surface of the writing member to provide a writing surface having the desired properties, or by incorporating selected components into the writing member so that the front surface exhibits the desired properties. Achieved.

In summary, the method of the present invention
a) providing a dry erase article as described herein;
b) writing a first writing content on the writing surface using a dry erase marker comprising ink having a surface tension less than the surface energy of the writing surface;
c) At least a portion of the first written content is typically wiped firmly with the hand using dry eraser, preferably no more than once, preferably only once, with a portion of the written content on the dry erase article. And erasing the image so that it is no longer visible.

  In accordance with the present invention, this method can be used to achieve low ghosting capability in writing over hours, days, or longer.

  The present invention also provides, in summary, dry erase markers that utilize fluids that have significantly lower surface tension than the fluids used in conventional dry erase markers.

  It has been found that the writing surface described herein provides surprising performance. Some advantages of the dry erase article of the present invention include good writing comfort with good ghosting resistance. Further, the dry erase article of the present invention has higher stain resistance when written with an inappropriate writing tool that is not a dry erase marker, for example, a so-called oil marker. Removal of the oily marker from the dry erase article of the present invention may require a solvent such as isopropanol, but writing with a conventional dry erase marker can be done only once using conventional dry eraser, or 2 It can be removed by rubbing and wiping. Furthermore, the dry erase articles of the present invention typically exhibit excellent mechanical durability and resistance to yellowing over time.

The present invention will be further described with reference to the drawings.
1 is a schematic cross-sectional view for explaining an embodiment of the present invention. This figure is not to scale, it is merely illustrative and not limiting.

  For the terms defined below, these definitions shall apply unless a different definition is given in the claims or elsewhere in the specification.

  Unless otherwise indicated, all numerical values representing molecular weights, amounts of components such as reaction conditions, and properties used herein and in the claims are modified with the word “about” in any case. It should be understood that Accordingly, unless otherwise objected to, the numerical parameters set forth in the foregoing specification and the appended claims are subject to the desired properties sought by those skilled in the art using the teachings of the present invention. It is an approximate value that can change accordingly. At a minimum, and not as an attempt to limit the application of the principle of equivalents to the claims, at least each numeric parameter takes into account the number of significant figures reported, and the usual estimation method. Must be interpreted by applying. Although all numerical ranges and parameters representing the broad scope of the present invention are approximate, the numerical values shown in the examples are reported as accurately as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

  Weight percent, percent by weight,% by weight, and the like are calculated by dividing the weight of the material by the weight of the composition and multiplying by 100. A synonym for concentration.

  Citation of a numerical range by endpoint includes all numbers contained within that range (eg 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, And 5). As used herein and in the appended claims, the singular forms “a”, “an”, and “the” refer to a plurality of referents unless the content clearly dictates otherwise. Is included. Thus, for example, reference to a composition containing “a compound” includes a mixture of two or more compounds. As used herein and in the appended claims, the term “or” is generally employed in its sense including “and / or” unless the content clearly dictates otherwise.

Dry Erase Article Construction An example of a dry erase article of the present invention is shown in FIG. 1, where a dry erase article 10 including a writing member 12 and an optional support member 14 is shown. In accordance with the present invention, the front surface 16 or writing surface of the writing member 12 exhibits both good writing acceptability and good ghosting resistance. In some embodiments, the support member 14 comprises a structural member 18 and an optional primer layer 20 to achieve the desired inter-ply adhesion to the writing member 12. In some embodiments, the article 10 may further comprise an optional adhesive 22 on the back side, eg, on the back side of the support member 14 shown in the figure, the adhesive 22 bonding the article 10 to a desired article to be adhered. Bring a means. In some embodiments, the article 10 further includes one or more locations for securing members of the article 10 together, facilitating handling of the article 10, providing means for attaching the article 10 to a support surface, and the like. A frame member 24 may be provided at the edge of the frame.

  The articles of the present invention can be made in a variety of desired embodiments, illustratively single or padded sheets, such as paper analogs, films, adhesive back labels incorporated into folders, notebooks Covers, dry erase articles and the like are included.

  The acceptability of the ink on the writing surface 16 as an indicia written in the absence of ink drops can be defined as the “wetting” of the dry erase writing surface. Wetting refers to a writing line that can maintain shape and continuity as the solvent dries. Solvent dewetting from the writing surface causes line movement or breakage at some point, resulting in voids in the written content. Acceptable wettability (or writing without dewetting) is typically achieved when the surface energy of the writing surface is greater than the surface tension of the solvent component in the marker ink. Wet tension test method ASTM D 2578-08 (Standard Testing Method for Wetting Tension of Polyethylene and Polypropylene Films) is a direct measurement method for surface wettability. In this test method, a liquid with a known surface tension is applied to the surface. If the liquid does not form water droplets after 2 seconds, ie does not dewet, it is said to wet the surface. The highest surface tension value of a liquid that does not produce water droplets after 2 seconds is considered to be the surface wetting tension.

The solvent composition of the dry erase marker is typically listed on the marker or reported on the marker's MSDS (Product Safety Data Sheet). Common solvents for dry erase markers include, for example, ethanol, isopropanol, methyl isobutyl ketone, and n-butyl acetate. One solvent with high surface tension is n-butyl acetate, which has a surface tension of about 25 mJ / m ² . Thus, in some embodiments, the dry erase surface can be made wettable by a solvent with a surface tension of about 25 mJ / m ² or less. In one embodiment, the surface energy of the writing surface is in the range less than about 26 mJ / ^{m 2} ~ about 38 mJ / ^{m 2} of. In another embodiment, the surface energy of the writing surface is in the range less than about 30 mJ / ^{m 2} ~ about 38 mJ / ^{m 2} of.

In addition, the writing surface of the article of the present invention allows a user to write once with a dry erase marker and wipe away any signs that are no longer desired (eg, using a dry cloth or dry eraser). Provides an “erasability” level. Acceptable erasability is achieved when the surface energy of the writing surface is low enough to prevent the persistent adhesion of the binder and other solids in the marker ink to the writing surface. As used herein, good erasability is considered to erase the written content substantially completely by wiping with a hand no more than twice, preferably only once using dry erase. It is. Wiping once by erasing is defined as a single direction in which the erasing passes through the writing surface. By hand means a force of about 0.4 N / cm ² . When a smaller force is used, a wiping operation may be further required. The surprising erasable performance provided by the writing surface of the present invention makes it easier for more people to use and eliminates the need for violent rubbing operations during erasure that are generally required. Reduces writing surface wear. Furthermore, since easy erasability is achieved, the user has a stronger cleaning agent with an unpleasant odor, and a tool that tends to damage the writing surface, thereby shortening the lifetime of the surface. There will be no need to clean the writing surface with.

  Various types of dry eraser can be used in the present invention. Illustrative examples of eraser materials include compression and woven felts of synthetic and / or natural (eg, wool) materials, cellulose, foam rubber, neoprene, fabrics, pile fabrics, melamine fibers, and similar materials that have been used. It is done. Preferably, the selected eraser material is inherently non-abrasive in order to increase the durability of the writing surface.

  The writing surface of the present invention also provides marker writing resistance on the surface. The occurrence of ghost in dry erasure writing may occur when the marker ink penetrates the surface, and is difficult or difficult to remove by simple wiping by dry erase. This penetration tends to occur when the writing surface is porous or soft. The present invention provides a highly cross-linked writing surface that is not porous and prevents ghosting due to solvent penetration into the writing surface. As a result, the writing surface of the article of the present invention exhibits excellent ghost generation resistance.

  Optional support member 14 is selected to provide desired performance, for example, background color on the writing surface, reflective properties in the case of dry erase articles with improved projection capabilities.

  In some embodiments, the dry erase article comprises a writing member 12 on one side of the support member 14, an optional adhesive (not shown) on the second side of the support member 14, and a back side of the adhesive. With an optional release liner (not shown).

  In some embodiments, the dry erase article is a substrate with a cured coating on a portion of one side of the substrate and an adhesive on a portion of the other side, the article being later assembled. It is laminated on a second base material to be a dry erase board.

Writing Member The advantageous advantages of the present invention are achieved by a writing member having a writing surface as described herein. The writing surface may be formed from the curable coating composition, for example, by applying the composition to a substrate and curing, or by forming a self-supporting cured film from the composition.

In an exemplary embodiment, the writing member comprises a coating or film formed by a radiation curable coating. The radiation curable coating incorporates acrylate monomers and other polymerizable monomers or polymers, and at least one polymerizable low surface energy monomer, oligomer, or polymer. The low surface energy monomer, oligomer, or polymer may be a fluorocarbon, silicone, or hydrocarbon. This low surface energy monomer, oligomer, or polymer is added to the formulation to reduce the surface energy of the radiation curable coating but still provide complete wetting of the dry erase marker on the surface. After curing, the surface coating has a wetting tension of from about 30 to less than about 38 mJ / m ² as measured by ASTM D 2578-08.

In another embodiment, the present invention comprises a radiation curable coating on a film or paper substrate having a wetting tension of from about 20 to about 30 mJ / m ² , herein referred to as an “ultra-low wetting tension” dry erase article. Called. The advantage of such an “ultra-low wetting tension” dry erase article is that the oily marker dewets, i.e. creates water droplets, signaling the user that the wrong marker has been used. However, commercially available dry erase markers do not efficiently wet such writing surfaces, but instead create water droplets to form voids during writing. Accordingly, one aspect of the present invention is to provide a dry erase marker that wets on an “ultra-low wetting tension” surface having a wetting tension of about 20 to about 30 mJ / m ² . Such wetting of the writing surface can be achieved by re-specifying the marker ink, for example by incorporating a surfactant therein to reduce the surface tension of the ink. Such inks efficiently wet such writing surfaces, but will easily be erased even if the residence time is long on the surface.

When using conventional dry erase markers, it is typically desirable for writing surface 16 having a surface energy of about 26 mJ / m ² or greater. This surface energy of the writing surface prevents typical dry erase and oily markers from forming water droplets on the writing surface. When the written indicia is received as a continuous layer, it prevents water drops, or “slipping”, from occurring on the lines forming the written indicia. Typical dry erase marker solvents include ethanol, isopropanol, methyl isobutyl ketone, and n-butyl acetate. In order for the marker to efficiently infiltrate on the dry erase surface without causing water droplets, the surface energy of the dry erase surface must be greater than the surface tension of the solvent in the marker ink. The solvent listed above with the highest surface tension is n-butyl acetate, with a surface tension of about 25 mJ / m ² . Accordingly, in one embodiment, the dry erase article writing surface has a surface energy of about 26 mJ / m ² or greater. In an alternative embodiment, the writing surface of the dry erase article has a surface energy greater than or equal to about 30 mJ / m ² as measured by ASTM D 2578-08. In addition, the written indicia can be quickly removed from the dry erase article, preferably with minimal wiping and absorption of ink by the minimum dry erase article. Acceptable removability of the ink can be achieved when the surface energy of the writing surface is low enough to prevent the binder and other solids in the marker ink from sticking to the writing surface persistently. Accordingly, in one embodiment, the writing surface of the dry erase article has a surface energy of about 38 mJ / m ² or less. In an alternative embodiment, the writing surface of the dry erase article has a surface energy of about 35 mJ / m ² or less as measured by ASTM D 2578-08.

  In some embodiments, the writing member comprises a non-sticky crosslinked polymer layer. The polymeric layer is made from a radiation curable coating formulation containing at least one low surface energy monomer, oligomer, or polymer selected from the group of polymerizable fluorocarbons, silicones, or hydrocarbon monomers. When radiation cured, the non-tack cross-linked polymer layer provides an ink receiving surface while simultaneously providing improved erasability and ghosting resistance.

  The non-adhesive cross-linked polymer layer may be formed by polymerization of the precursor composition, but other methods (eg, cross-linking of polymers or blends thereof using chemical means or ionizing radiation) may be used. Useful precursor compositions typically include one or more polymerizable materials (eg, monomers and / or oligomers that may be monofunctional and / or multifunctional), curing agents, and optionally inorganic. Contains particles. The polymerizable material may be, for example, free radical polymerizable, cationic polymerizable, and / or condensation polymerizable. Useful polymerizable materials include, for example, acrylates and methacrylates, epoxies, polyisocyanates, and trialkoxysilane terminated oligomers and polymers. Preferably, the polymerizable material includes a free radical polymerizable material.

  Useful free radical polymerizable materials include, for example, free radical polymerizable monomers and / or oligomers, either or both of which may be monofunctional or polyfunctional. Typical free radical polymerizable monomers include styrene and substituted styrene (eg, α-methylstyrene), vinyl ester (eg, vinyl acetate), vinyl ether (eg, butyl vinyl ether), N-vinyl compound (eg, N-vinyl). -2-pyrrolidone, N-vinylcaprolactam), acrylamide and substituted acrylamides (eg, N, N-dialkylacrylamide), and acrylates and / or methacrylates (ie, generally referred to herein as (meth) acrylates) (eg, , Isooctyl (meth) acrylate, nonylphenol ethoxylate (meth) acrylate, isononyl (meth) acrylate, diethylene glycol (meth) acrylate, isobornyl (meth) acrylate, 2 (2-ethoxyethoxy) ethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, butanediol mono (meth) acrylate, β-carboxyethyl (meth) acrylate, isobutyl (meth) acrylate, 2 -Hydroxyethyl (meth) acrylate, (meth) acrylonitrile, isodecyl (meth) acrylate, dodecyl (meth) acrylate, n-butyl (meth) acrylate, methyl (meth) acrylate, hexyl (meth) acrylate, (meth) acrylic acid , Stearyl (meth) acrylate, hydroxy-functional polycaprolactone ester (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxymethyl (meth) acrylate, hydroxypropyl (Meth) acrylate, hydroxyisopropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxyisobutyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, ethylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, tri Ethylene glycol di (meth) acrylate, 1,3-propylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, 1,4-cyclohexanediol di (meth) acrylate, 1,5-pentanediol di (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, glycerol tri (meth) acrylate, Pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and neopentyl glycol di (meth) acrylate) and the like.

  Representative free radical polymerizable oligomers are commercially available from UCB Chemicals (Smyrna, Georgia) (eg, under the trade name “EBECRYL”), and those available from Sartomer Company (Exton, Pennsylvania) (eg, product The name “KAYARAD” or “CN”).

  Depending on the choice of polymerizable material, the precursor composition may optionally contain one or more curing agents that assist in the polymerization of the polymerizable material. The choice of curing agent for a particular polymerizable material depends on the chemistry of the copolymerizable material. For example, in the case of an epoxy resin, one would choose a curing agent (eg, dicyandiamide, onium salt, or polymercaptan) that is well known to be typically used with epoxy resins. In the case of free radical polymerizable resins, free radical thermal initiators and / or photoinitiators are useful curing agents.

  Typically, any curing agent is used in an amount effective to promote monomer polymerization, and the amount will vary depending on, for example, the type of curing agent, the molecular weight of the curing agent, and the polymerization process. . The optional curing agent is typically included in the precursor composition in an amount ranging from about 0.01 weight percent to about 10 weight percent, based on the total weight of the precursor composition, but in higher amounts or Smaller amounts may be used. For example, a precursor composition by exposure to a heat source (eg, heat, infrared), electromagnetic radiation (eg, ultraviolet and / or visible radiation), and / or particulate radiation (eg, an electron beam or (of) gamma radiation). The object may be cured.

  The coating composition that forms the writing surface must be fully cured to retain the marker on a surface that can be easily removed by direct contact with the dry eraser. In particular, at least the portion of the composition that forms the writing surface must be completely cured. Various curing strategies are well known to those skilled in the art, and a suitable one can be easily selected and determined in part by the characteristics of the curable coating composition, the other components of the article, and the manufacturing facility. Examples of techniques for maximizing the cure of UV cured coating compositions include curing under nitrogen, using a new UV bulb, cleaning the UV bulb before use, matching the UV bulb output spectrum with the absorbance of the initiator, As well as slow and / or long treatments. In some embodiments, when a dry erase article is allowed to elapse at room temperature, a certain amount of post-exposure curing can occur over time.

  The degree of cure of the coated dry erase article can be tested by carrying out the dry erase test described in the Test Method section on a sample having a dwell time of writing before erasing of 1 day. If the dry erase article is better erased after post-curing, the initial curing may not be sufficient. Therefore, in addition to the first curing, a second curing process may be required. The second cure may use the same radiation source as the first cure, or may use a different radiation source. Preferred second curing methods include heat, electron beam, and gamma ray treatment.

  If the optional curing agent is a free radical initiator, the amount of curing agent is preferably in the range of about 1 weight percent to about 5 weight percent based on the total weight of the precursor composition, but a greater amount Or lesser amounts may be used. Useful free radical photoinitiators include, for example, benzoin ethers such as benzoin methyl ether and benzoin isopropyl ether, substituted benzoin ethers (eg anisoin methyl ether), substituted acetophenones (eg 2,2-dimethoxy-2-phenylacetophenone) ), Substituted α-ketols (eg, 2-methyl-2-hydroxypropiophenone), benzophenone derivatives (eg, benzophenone), and acylphosphine oxides. Typical commercially available photoinitiators include Ciba Specialty Chemicals (Tarrytown, New York) trade names “IRGACURE” (eg, IRGACURE ™ 651, IRGACURE ™ 184, and IRGACURE ™ 819), or “ DAROCUR ”(eg, DAROCUR ™ 1173, DAROCUR ™ 4265), and BASF (Parsippany, New Jersey trade name“ LUCIRIN ”(eg,“ LUCIRIN TPO ”).

  Typical free radical thermal initiators include peroxides such as benzoyl peroxide, dibenzoyl peroxide, dilauryl peroxide, cyclohexane peroxide, methyl ethyl ketone peroxide, hydroperoxides such as tert-butyl hydroperoxide and cumene hydro Peroxides, dicyclohexyl peroxydicarbonate, t-butyl perbenzoate, and azo compounds such as 2,2, -azo-bis (isobutyronitrile).

The low surface energy monomer, oligomer, or polymer may be selected from the group of fluorocarbon, silicone, or hydrocarbon monomers. Fluorocarbon monomers suitable for the present invention include, but are not limited to, perfluoroacrylates or methacrylates such as C ₄ F ₉ -based sulfonamide acrylate and C ₃ F ₇ -based sulfonamide acrylate. Illustrative of useful fluorocarbon monomers _{herein, C 4 F 9 SO 2 N} (CH 3) C 2 H 4 O-CONHC 6 H 5 -
_{CH 2 C 6 H 5 NHCO-} OC 2 H 4 OCOCH = CH 2 ( also known as _{MeFBSE-MDI-HEA), C} 4 F 9 SO 2 N (CH 3) C 2 H 4 O-CONH (CH 2) _{6 NHCO-OC 2 H 4 OCOCMe} = CH 2, C 4 F 9 SO 2 N (CH 3) C 2 H 4 O-CONH (CH 2) 6 NHCO-OC 12 H 24 OCOCH = CH 2, and _CF 3 CH _{2 O-CONH C 6 H 5} CH 2 C6H 5 NHCO-OC 2 H 4 OCOCH = CH 2 and the like. As perfluoroacrylate suitable for the present invention, C ₁ -C ₆ perfluoroalkyl acrylate, ie RSO ₂ NMeC ₂ H ₄ OC (O) CH═CH ₂ , wherein R is C _n F2 _{n + 1} , n is 1 to 1 6 is an integer of 6).

  Another group of suitable fluorochemical monomers are described in US Pat. Nos. 7,279,210 (Hulten et al.) And 7,199,197 (Caldwell et al.). These fluoroacrylate monomers are represented by the following formula.

式中、ｎは１〜６（１と６を含む）の範囲の整数であり、ｐは２〜３０（２と３０を含む）の範囲の整数であり、Ｒ’はＨ、ＣＨ_３、又はＦであり、Ａはヒドロカルビレン基であり、

式中、ＲはＨ又は１〜４個の炭素原子を有するアルキル基であり、ｍは２〜８（２と８を含む）の範囲の整数であり、Ｒ_ｆはＣ_ｎＦ２_ｎ＋１であり、ｙは０〜６（０と６を含む）の範囲の整数であり、ｑは１〜８（１と８を含む）の範囲の整数である。

Where n is an integer in the range of 1-6 (including 1 and 6), p is an integer in the range of 2-30 (including 2 and 30), and R ′ is H, CH ₃ , or F, A is a hydrocarbylene group,

Wherein R is H or an alkyl group having 1 to 4 carbon atoms, m is an integer in the range of 2 to 8 (including 2 and 8), R _f is C _n F2 _{n + 1} , y is an integer in the range of 0 to 6 (including 0 and 6), and q is an integer in the range of 1 to 8 (including 1 and 8).

からなる群から選択される。 In some embodiments, A is —C ₆ H ₁₂ —,

Selected from the group consisting of

  Other fluorochemical additives suitable for the present invention include perfluoropolyether urethane acrylates described in US Pat. No. 7,173,778 (Jing et al.).

  Fluorochemical oligomers suitable for use in the dry erase articles of the present invention include 3M Company (St. Paul, MN) FLUORAD ™ FC-4430 and FC-4432, which are commercially available chemicals. .

  Suitable fluorochemical polymers for use in the dry erase article of the present invention include, for example, perfluoropoly having poly (alkylene oxide) repeat units as described in WO 2009/076389 (Yang et al.). Examples include ether polymers.

  Suitable silicone monomers for the present invention include, but are not limited to, silicone acrylate monomers. Representative silicone acrylate monomers suitable for use herein include BYK-Chemie GmBH (Wesel, Germany) BYK-371 Reactive Silicone Surface Additive, BYK-373 Reactive SiliconSurfid SiliconS Additive, BYK-UV 3500 Surface Additives for Radiation Curvable Systems, BYK-UV 3530 Surface Additives for Radiation Curvable Systems, BYK-UVfur 3570A es for Radiation Curable Systems, and BYK SILCLEAN (TM) 3710 Surface Additives to Improve Surface Cleanability and the like. 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 the coating. These hydrocarbon monomers are characterized by long side chains that can form a crystal structure on the surface. Suitable hydrocarbon monomers include but are not limited to octadecyl acrylate.

In one embodiment of the invention, the low surface energy monomer, oligomer or polymer is added to the coating formulation at a concentration sufficient to produce a cured coating having a wetting tension of about 26 to about 36 mJ / m ^2. . Preferably, the cured coating has a wetting tension of about 30 to about 36 mJ / m ² .

  In some embodiments, the radiation curable material comprises the oligomer, monomer, and / or polymer in one or more solvents with a specified amount of any particle or nanoparticle, for example, added to a writing member. Imparts hardness and durability.

  Nanoparticles can be surface modified, which means that the nanoparticles have a modified surface and the nanoparticles provide a stable dispersion. A “stable dispersion” is, for example, a colloid after standing for a period of time, for example about 24 hours, at room temperature (ie, about 20-22 ° C.) and atmospheric pressure, without ambient electromagnetic forces. Refers to a dispersion in which shaped nanoparticles do not agglomerate.

  The surface-modified colloidal nanoparticles are optionally present in an amount effective to enhance the durability of the final element, i.e., the optical element, in the polymer coating used as the coatable composition herein. It may be present with the nanoparticles. The surface-modified colloidal nanoparticles described herein include a nanoparticle coatable composition, for example, such that the nanoparticles form a stable dispersion within the coatable composition. Can have various favorable attributes such as compatibility of the nanoparticles, reactivity of the nanoparticles with the coatable composition, and low impact or viscosity of the uncured composition. A combination of surface modification can be utilized to manipulate the uncured and cured properties of the composition. Surface-modified nanoparticles can improve the optical and physical properties of the coatable composition, such as improving the mechanical strength of the resin, increasing the amount of solids loaded in the coatable composition Such as minimizing changes in viscosity during maintenance and maintaining optical clarity while increasing the amount of solids loaded into the coatable composition.

  In some embodiments, the nanoparticles are surface modified nanoparticles. Suitable surface modified colloidal nanoparticles may include oxide particles. Nanoparticles may include a range of particle sizes over a known particle size distribution for a given material. In some embodiments, the average particle size may be in the range of about 1 nm to about 100 nm. The particle size and particle size distribution can be measured by a well-known method using, for example, a transmission electron microscope (“TEM”). Suitable nanoparticles may comprise a metal oxide selected from any of a variety of materials, such as alumina, tin oxide, antimony oxide, silica, zirconia, titania, and combinations of two or more thereof. The surface modified colloidal nanoparticles can be substantially completely condensed.

  In some embodiments, the silica nanoparticles can have a particle size in the range of about 5 to about 100 nm. In some embodiments, the silica nanoparticles can have a particle size in the range of about 10 to about 30 nm. Silica nanoparticles may be present in the coatable composition in an amount of about 10 to about 100 phr. In some embodiments, the silica nanoparticles may be present in the coatable composition in an amount of about 30 to about 90 phr. Silica nanoparticles suitable for use in the coatable composition of the present invention include Nalco Chemical Co. (Naperville, Ill.) Under the product name NALCO ™ COLLOIDAL SILICAS. Suitable silica products include NALCO products 1040, 1042, 1050, 1060, 2327 and 2329. Suitable fumed silica products include, for example, Degussa AG (Hanau, Germany) as AEROSIL ™ series OX-50, -130, -150, and -200, and Cabot Corp. (Tuscola, IL) include products sold as CAB-O-SPERSE ™ 2095, CAB-O-SPERSE ™ A105, and CAB-O-SIL ™ MS. Surface treatment of the nanoparticles can provide a stable dispersion in a coatable composition (eg, a polymer resin). Preferably, the nanoparticles are stabilized by a surface treatment so that the particles are well dispersed in the coatable composition, resulting in a substantially uniform composition. In addition, the nanoparticles can be modified with at least a portion of their surface with a surface treatment so that the stabilized particles can be copolymerized or reacted with the coatable composition during curing.

  Silica nanoparticles can be treated with a surface treatment agent. Suitable surface treatment agents for the particles contained in the coatable composition include, for example, isooctyltrimethoxy-silane, N- (3-triethoxysilylpropyl) methoxyethoxyethoxyethylcarbamate (PEG3TES), SILQUEST ™ A1230, N- (3-triethoxysilylpropyl) methoxyethoxyethoxyethylcarbamate (PEG2TES), 3- (methacryloyloxy) propyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3- (methacryloyloxy) propyltriethoxy Silane, 3- (methacryloyloxy) propylmethyldimethoxysilane, 3- (acryloyloxypropyl) methyldimethoxysilane, 3- (methacryloyloxy) propyldimethyle Xysilane, 3- (methacryloyloxy) propyldimethylethoxysilane, vinyldimethylethoxysilane, phenyltrimethoxysilane, n-octyltrimethoxysilane, dodecyltrimethoxysilane, octadecyltrimethoxysilane, propyltrimethoxysilane, hexyltrimethoxysilane, Vinylmethyldiacetoxysilane, vinylmethyldiethoxysilane, vinyltriacetoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriphenoxysilane, vinyltri-t-butoxysilane, vinyltris-isobutoxysilane , Vinyltriisopropenoxysilane, vinyltris (2-methoxyethoxy) silane, styrylethyltrimethoxysilane, merca Topropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, acrylic acid, methacrylic acid, oleic acid, stearic acid, dodecanoic acid, 2- [2- (2-methoxyethoxy) ethoxy] acetic acid (MEEAA), β -Compounds such as carboxyethyl acrylate, 2- (2-methoxyethoxy) acetic acid, methoxyphenylacetic acid, and mixtures of two or more thereof.

  In some embodiments, the average particle size (eg, particle size) can be in the range of about 1 nm to about 1000 nm. In addition to the above particle sizes, the use of smaller and larger average particle sizes is also contemplated. In an embodiment of the present invention, at least some of the particles may be surface modified by the above method. In other embodiments, all particles are surface modified. In yet other embodiments, the particles are not surface modified.

  Of course, the coating composition used in the manufacture of the writing member of the present invention may include rheology modifiers such as JAYLINK ™ Rheology Modifiers, colorants (eg, dyes and / or pigments), flame retardants, oxidations, and the like. Arbitrary additives such as an inhibitor, a stabilizer, an ozone degradation inhibitor, a plasticizer, an ultraviolet absorber, a hindered amine light stabilizer (HALS) and the like may be included to improve or adjust desired properties.

Support Member In some embodiments, for example, if the self-support of the writing member is not sufficient, or other properties such as magnetism, roll resistance, tear resistance, dimensional stability, color, etc. are present in the dry erase article. If desired, the dry erase article may further comprise a support member on the back side of the writing member. Depending on the embodiment, the support member may be a single layer or multiple layers.

  Examples of suitable substrates for use as support members include glass, paper, coated paper, paper film laminates, polymer films, polymer sheets and metal foils, metal sheets, porcelain sheets, and the like. It is not limited. Polymer films and sheets include, but are not limited to, polyester, polypropylene, polyethylene, polystyrene, cellulose acetate, polycarbonate, polyacrylate, and polyvinyl chloride. Polymer films and sheets may include copolymers, blends, or coextruded multilayer films of the above polymers or other polymers. If desired, the support may include an adhesive on its back surface, or further comprise an adhesive, to facilitate bonding of the resulting dry erase article to a substrate or surface.

  In embodiments where good projectability is desired for a dry erase article, the writing member is preferably substantially transparent and the support member has reflective properties. For example, the projection member disclosed in US patent application Ser. No. 12 / 684,565 (filed Dec. 15, 2009) may be used in the dry erase article of the present invention.

  If desired, the support member is opaque and / or colored to give the resulting dry erase article the desired appearance. Also, a decorative or organizational figure, heading, etc. is provided on the article, and a desired decorative mark, information heading (eg “NAME”) embedded in the writing member, on the back of the writing member, on the front of the support, etc. , “IN”, “OUT”, etc.) may be shown to the observer.

Dry Erase Marker In some embodiments, the dry erase article of the present invention may be used with a variety of conventional dry erase markers.

Commercial dry erase marker inks typically have a surface tension of less than about 30 mJ / m ² . There are generally two types of dry erase markers, namely alcohol solvent-based markers and ketone solvent-based markers. The alcohol marker solvent is typically ethanol and isopropanol. The ketone marker solvent is typically methyl isobutyl ketone and n-butyl acetate. The surface tension values of these solvents are listed in the table below.

In order for the dry erase marker to be completely wetted, the wet tension of the dry erase board needs to be larger than the surface tension of the marker ink. Thus, as measured by ASTM D2578, the surface wetting tension must typically be 25 mJ / m ² or greater in order for commercially available markers to wet on the surface.

In some embodiments of the invention, where the writing surface has an ultra-low surface wetting tension, i.e., less than about 30 mJ / m < ² >, an effective amount of one or more surfactants to reduce the surface tension of the ink formulation. An agent can be added to the ink in the dry erase marker. The surfactant may be anionic, cationic, or nonionic. Due to the limited choice of markers that can be used for efficient writing at such ultra-low wetting tensions, such dry erase articles attempt to graffiti on the top surface or do not contain inappropriate markers, such as oily markers, rather than dry erase markers. Prevent use with caution.

  As examples of suitable surfactants, 3M Company (St. Paul, MN) FLUORAD ™ FC-170C, FC-430, and FC-171, Evonik Industries (Parsippany, NJ) SIVENTO DYNASYLAN ™ F8810 Ausimont Inc. (Thorofare, NJ) FOMBLIN ™ C, Gelest Inc. (Kent, ME) Silane B-1092, Solvay Solexis (West Deptford, NJ) FLUOROLINK (TM) 3, and Huls America (Cincinnati, OH) DYNASYLAN (TM) FC-8261. . The above FLUORAD ™ FC-4430 and FC-4432 can be used as surfactants in some ink formulations according to the present invention.

  The invention is further illustrated by the following specific, non-limiting examples.

Test Method The following test method was used.

  Marker dewetting: The dry erase surface was marked using 14 different markers including 7 brands of dry erase markers. Dry erase markers are AVERY ™ MARKS-A-LOT ™ (Avery-Denison, Pasadena, Cal.), BEIFA ™ proprietary brand markers (Beifa, Tokyo, Japan), BIC ™ Dry Erase markers. (BIC Corporation, Milford, Conn.), DIXON (TM) Dry Erase Markers (Dixon Ticondero Co., Heathrow, Fla.), EXPO (TM) Bold (Sanford Corp, OR, BellwoodEIL, TM). (Sanford Corp.), and QUARTET ™ Markers (Acco, Inc, Lincolnshi) And e, IL) and. All markers were chisel-type nibs. Two color markers from each brand were selected, one black and the other red, green or blue. A typical dry erase sample was about one sheet of paper. For each brand of marker, a horizontal margin of about 2.5 cm above and below the sample was secured for the brand marker. Using the first marker, write the brand name of the marker on the left side of the 2.5 cm wide margin, and use the second marker to write the brand name of the same marker on the right side of the 2.5 cm vertical margin It is. In this way, all the writing by the markers of each brand was arranged in a horizontal shape that can be erased at one time.

  After the dry erase surface of the present invention was fabricated, each ink line was examined for dewetting. Dry erasing ink dewetting, or water droplets, was demonstrated by the appearance of misalignment in the ink lines or shrinkage of the ink lines. The total number of markers that caused dewetting was calculated. Since 14 different markers were used in the writing test, the range of dewetting scores could be 0-14. For example, when there was no marker dewetting, the dewetting score was set to zero. If there were 10 marker dewettings, the score was 10.

Removal of dry erase writing: After writing on the target writing surface and passing the writing at room temperature as instructed, the removability of dry erase writing was tested as follows. The sample was placed on a hard plane. The writing was erased using EXPO ™ Dry Eraser (Sanford Corp.). The area of the eraser in contact with the writing surface was about 12.5 cm × 5 cm. A 12.5 cm × 5 cm brass weight weighing 2.5 kg was placed on top of the eraser and a pressure of 0.4 N / cm ² was applied. The eraser with the weight was passed over the writing line with the first marker without further pressing with the hand. The first writing line included writing with two types of markers of the first brand. Except for a few details, we counted the number of erasure passes required to remove all marker writing. If the writing was still readable after passing the eraser 10 times, the erasure operation was stopped. Subsequently, the erasing operation was continued up to 10 times using a wet paper towel. For the marker brand, the total number of passes was recorded and the seven brands were summed. In some cases, passing the eraser once removed all writing of both markers. In other cases, it took more than twice to remove the writing. The minimum dry erase removal score is 7 because there are a total of 7 lines of dry erase marker writing.

Wetting tension: The wetting tension of the dry erase surface of the present invention was measured according to ASTM D 2578-08 (September 1, 2009). All surfaces were first cleaned with isopropanol and paper towels. The surface was dried for 10 minutes. By 2 mJ / ^{m 2} range from 30~48mJ / ^{m 2,} was obtained pen for wetting tension from UV Process Control (Chicago, IL) . With pure solvent as described in Table 2 was measured wetting tension of 30 m J / m ² or less of the surface.

  This liquid was applied to the dry surface with a pen or cotton swab. If for 2 seconds the liquid has not completely formed water droplets or if the liquid has been kept in place without displacing, the liquid will wet the surface. The wetting tension of this film is the highest surface tension pen or liquid that wets the film for 2 seconds.

  Adhesion to dry erase surface: The relative peel adhesion of a standard tape to the writing surface is a measure of the relative surface energy of the surface. The peel adhesion of 3M ™ SCOTCH ™ 810 Magic Tape to the writing surface was measured. First, the surface was cleaned with isopropanol and dried overnight at 23 ° C. (73 ° F.) and 50% RH. A ball slide was inserted into the lower gripping tool of a tensile tester (MTS, Eden Prairie, MN). 3M ™ High / Low Tack 9415 Double Coated Tape was affixed to the ball slide with the re-adhesive adhesive side up. Subsequently, a dry erase surface was attached to the 9415 tape. A 2.54 cm wide 810 tape length was attached to the dry erase surface with the tape protruding at least 20 cm from the front edge of the surface. A standard 2 kg rubber-coated roller was rolled separately 4 times at a speed of about 64 cm / min to extend the tape onto the film. The free end of the tape was attached to the upper grip of the tensile tester. The tape was peeled from the film while maintaining a peel angle of 90 ° by moving the ball slide at 90 ° at a speed of 30 cm / min and the same speed of 30 cm / min. The average peel adhesion value was recorded.

Materials The materials used in Examples and Comparative Examples are shown in Table 3.

Marker: In order for the dry erase marker to be completely wetted, the wet tension of the dry erase surface must be greater than the surface tension of the marker fluid. Typically, the surface wetting tension needs to be about 28 mJ / m ² or more for all markers in order to write to the dry erase surface.

  A solution containing 10 wt% FC-4432 surfactant in isopropanol was prepared. The black and green EXPO ™ Low Odor dry erase marker tips were injected with 0.5 mL of surfactant solution using a syringe and allowed to infiltrate and mix overnight.

  Preparation of functionalized nanosilica: A 12 liter flask was charged with 3000 g of aqueous colloidal silica solution (eg, NALCO ™ 2327 from Nalco Company) and stirring was initiated. 3591 g of 1-methoxy-2-propanol (such as DOWANOL ™ PM from Dow Chemical (Midland, MI)) was then added. In a separate container, 189.1 g of 3-methacryloxypropyltrimethoxysilane (such as SILQUEST ™ A-174 from Momentive Performance Materials (Wilton, CT)) was mixed with 455 g of 1-methoxy-2-propanol. . This premix solution was added to the flask and rinsing was performed with 455 g of 1-methoxy-2-propanol. The mixture was heated to 80 ° C. for about 16 hours. The mixture was cooled to 35 ° C. This mixture was placed with a recovery flask for vacuum distillation (30-35 Torr (4000-4700 Pa), 35-40 ° C.). An additional 1813.5 g of 1-methoxy-2-propanol was added to the reaction flask during the distillation. A total of 6784 g of distillate was recovered. The% solids of the mixture were tested by drying a small sample in a tared aluminum pan for 60 minutes in a 105 ° C. oven. The mixture was found to be 52.8% solids. An additional 250 g of 1-methoxy-2-propanol was added and the mixture was stirred. % Solids were tested and found to be 48.2%. The mixture was recovered by filtration through cheesecloth to remove particle debris.

  Example 1-906 hardcoat containing 0.075% HFPO-UA: The synthesis of HFPO-UA is described in US Patent No. 7,173,778. HFPO-UA was diluted in MEK to 25% solids. The MEK solution of HFPO-UA was added to the 906 hard coat solution to obtain a final concentration of 0.075% solid HFPO-UA relative to the 906 hard coat solid. The solution was subsequently diluted with ethyl acetate to 25% solids. This formulation was coated with a 9 inch (23 cm) wide continuous coater equipped with a coating, drying, UV curing, and coating film winding station. The coating formulation was applied by a coating die onto a 3 mil (76 micrometer) thick white polyester film. After coating, the film was passed through a forced air oven 30 feet (9.1 m) in length and dried at 130 ° F. (54 ° C.). Subsequently, the film was advanced into a UV curing chamber containing a H + bulb under a nitrogen purge. The oxygen concentration in the curing chamber was less than 100 ppm. The coater line speed was 50 ft / min (15.2 m / min) and the dry thickness of the coating on the film was 2 μm.

906 hard coat comprising an embodiment 2-10% of _{MeFBSEA (C 4 F 9 SO 2} NMeC 2 H 4 OC (O) CH = CH 2):
MeFBSEA was synthesized by the procedure described in WO200130873 (Savu et al.). MeFBSEA was added to the 906 hard coat at a value of 10% based on solids. After mixing, the solution was diluted with MEK to 30% solids. This solution was coated onto a 2 mil (50 micrometer) clear polyester film using a # 6 Mayer rod. The coated film was dried at 100 ° C. for 1 minute. The film with the dry coating was passed through a UV cure chamber containing an H bulb under a nitrogen purge.

EXAMPLE 3-15% of _{MeFBSEA (C 4 F 9 SO 2} NMeC 2 H 4 OC (O) CH = CH 2) 906 hard coat including: a MeFBSEA, was synthesized by the procedures described in WO 200130873 . MeFBSEA was added to the 906 hard coat at a value of 15% based on solids. After mixing, the solution was diluted with MEK to 30% solids. This solution was coated onto a 2 mil (50 μm) clear polyester film using a # 6 Meier rod. The coated film was dried at 100 ° C. for 1 minute. The film with the dry coating was passed through a UV cure chamber containing an H bulb under a nitrogen purge.

  Example 4 Hardcoat 2 with 0.075% HFPO-UA: Hardcoat 2 was prepared at 30% solids according to the formulation in Table 4. The preparation of functionalized nanosilica is described in the Examples section. A portion of 25% solids HFPO-UA in MEK was added to the solution to 0.075% HFPO-UA based on solids. The formulation was subsequently diluted to 25% solids with ethyl acetate. This formulation was coated, dried and cured in the same manner as in Example 1.

  Example 5-Hardcoat 2 containing 0.075% HFPO-PEG: Preparation of HFPO-PEG monomer is described in WO2009 / 076389. Hard coat 2 was prepared at 30% solids according to the formulation in Table 4. A portion of 25% solids HFPO-PEG in MEK was added to Hardcoat 2 solution to 0.075% HFPO-PEG relative to solids. The formulation was subsequently diluted to 25% solids with ethyl acetate. This formulation was coated, dried and cured as described in Example 1.

  Example 6 Hardcoat 2 with 1.4% HFPO-UA: Hardcoat 2 was prepared at 30% solids according to the formulation in Table 4. A portion of 25% solids HFPO-UA in MEK was added to the solution to 1.4% HFPO-UA based on solids. The formulation was subsequently diluted to 25% solids with ethyl acetate. This formulation was coated, dried and cured in the same manner as in Example 1.

  Example 7: A film was made using a 906 hard coat containing 0.15% HFPO-UA based on solids. The MEK solution of HFPO-UA was added to the 3M 906 hard coat, resulting in a HFPO-UA concentration of 0.075% solids relative to the 906 hard coat solid. The hard coat was diluted to 25% solids with ethyl acetate. This formulation was coated with a pilot coater on a 3 mil (76 μm) thick white PET film as described in Example 1.

  Example 8: Hardcoat 2 was prepared at 30% solids according to the method of Example 4. A portion of 25% solids FC-4430 in MEK was added to the solution to give 1.5% FC-4430 solids ratio in the formulation. The formulation was subsequently diluted to 25% solids with ethyl acetate. This formulation was coated, dried and cured in the same manner as in Example 1. The dry coating thickness was 2.0 μm.

  Example 9: Hardcoat 2 was prepared at 30% solids according to the method of Example 4. A portion of 25% solids FC-4430 in MEK was added to the solution to give 2.5% FC-4430 solids ratio in the formulation. The formulation was subsequently diluted to 25% solids with ethyl acetate. This formulation was coated, dried and cured in the same manner as in Example 1. The dry coating thickness was 2.0 μm.

  Example 10 Hardcoat 3 with 1% MeFBSEA: This hardcoat was prepared at 30% solids according to the formulation in Table 4. The preparation of functionalized nanosilica is described in the Examples section. Solid MeFBSEA was dissolved in ethyl acetate to give a 25% solids solution. The five materials listed in Table 5 were placed in a large stainless steel beaker and mixed. This formulation was diluted to 25% solids with ethyl acetate in the same beaker. This formulation was coated, dried and cured in the same manner as in Example 1. After coating, the film was heated at 50 ° C. for 2 days.

  Comparative Example C1-906 Hardcoat: The 906 hardcoat was diluted to 25% solids with ethyl acetate. This formulation was coated on a 3 mil (76 μm) thick white PET film with a pilot coater. This formulation was coated, dried and cured in the same manner as in Example 1. The dry coating thickness of the hard coat was 2 μm.

  Comparative Example C2-Hard Coat 2: The hard coat 2 formulation of Example 4 was prepared at 25% solids. This formulation was coated, dried and cured in the same manner as in Example 1. The dry coating thickness of the hard coat was 2 μm.

  Comparative Example C3-QUARTET ™ Total Erase Board Acco Corp. This board consists of a multi-functional acrylate coating on a coated paper on a medium fibreboard panel.

  Comparative Example C4: JFE Metal products and Engineering Inc. (JFE enamel sheet available from Tokyo, Japan).

  Comparative Example C5: Polyvision Corp. (Suwanee, GA) POLYVISION ™ enamel dry erase sheet.

Results Table 6 shows the wet tension, dewetting, and tape adhesion of the dry erase writing surface.

  Table 7 shows the writing comfort results of the dry erase marker mixed with the surfactant.

  The selected examples were tested for dry erase write removability after 1 day and 2 weeks on the surface of the examples (Table 8). By passing the dry eraser 7 times to remove all dry erase markers, easy removability for writing is shown. A removal score of 8 or more indicates that one or more ghost images written by a marker remain on the board after passing the eraser once.

  Although the present invention has been described in detail with reference to the preferred embodiments with reference to the accompanying drawings, it should be noted that various changes and modifications will be apparent to those skilled in the art. Such changes and modifications are to be understood as being included herein without departing from the scope of the present invention as defined by the appended claims.

  The complete disclosures of all patents, patent documents, and publications cited herein are incorporated by reference in their entirety. The above detailed description and examples are given for the purpose of understanding only. These should not be construed as making unnecessary limitations. The present invention should not be limited to the exact details shown and described, but it will fall within the scope of the invention as defined by the appended claims, with variations obvious to those skilled in the art. Because.

Claims (2)

From about 20 mJ / ^{m 2} has a writing surface of the surface wetting tension of less than about 38 mJ / ^{m 2,}
The writing surface comprises a radiation cured product of a radiation curable coating composition comprising at least one low surface energy monomer, oligomer, or polymer;
The low surface energy monomer, oligomer, or polymer is a dry chemical that is a fluorinated chemical having one or more side chains having the formula C _n F _{2n + 1} where n is an integer from 1 to 6 Erase article. a) providing a dry erase article according to claim 1;
b) writing a first writing content on the writing surface using a dry erase marker comprising an ink having a surface tension less than the surface energy of the writing surface;
c) erasing at least a portion of the first written content with no more than two passes using dry erase.

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