Water-dispersible direct thermal or inkjet printable media

Abstract

The dispersible recording material or medium comprises a water-soluble or water-dispersible paper substrate, a printable layer carried on the substrate, and a base coat between the substrate and the printable layer. The printable layer may be a thermoresponsive layer or an inkjet receiving layer, for example, containing a leuco dye and an acidic color developer. The binder material used in the base coat and the base coat itself are water-insoluble, but the recording material as a whole is designed to be water-dispersible, i.e., break down under the influence of water with minimal agitation. The binder material of the base coat is preferably a non-resin binder, a particulate binder, and / or a dispersion-derived binder, such as a latex. The use of such binder materials in carefully selected concentrations and with other elements results in a base coat that enables thermal printing of high-quality images on the thermoresponsive layer at high printing speeds.

Description

[Technical Field]

[0001] The present invention relates to direct thermal recording media, with particular application to such media that are water-dispersible. The present invention also relates to inkjet printable media that are water-dispersible. The present invention also relates to related methods, systems, and articles. [Background technology]

[0002] Many types of direct thermal recording media, sometimes referred to as thermally responsive recording materials, direct thermal recording media, or direct thermal media, are known. See, for example, U.S. Patent Nos. 3,539,375 (Baum), 3,674,535 (Blose et al.), 3,746,675 (Blose et al.), 4,151,748 (Baum), 4,181,771 (Hanson et al.), 4,246,318 (Baum), and 4,470,057 (Glanz). In these applications, a basic colorless or light-colored color-forming material, such as a leuco dye, and an acidic color-developing material are contained in a coating on a substrate, and when heated to a suitable temperature, the coating melts or softens, allowing the materials to react, thereby producing a colored mark or image where heat is applied. Thermally responsive recording materials have a characteristic thermal response that produces colored images of sufficient intensity upon selective heat exposure.

[0003] Several direct thermal recording media have been described or proposed in which the substrate or base material of the product is a water-soluble or water-dispersible paper material, and the resulting direct thermal recording media as a whole can be easily dissolved or dispersed by the end consumer. See, for example, U.S. Pat. No. 7,476,448 (Natsui et al.). While some such products are commercially available, they suffer from poor image quality. That is, when such products are fed through a conventional direct thermal printer and printed at a normal printing speed, e.g., 6 inches per second (ips), the resulting image quality is typically so poor that the barcode image cannot be reliably scanned and read with a standard barcode reader. The poor image quality is believed to be due to the product's outer surface being too rough or not smooth, which can occur due to wrinkling or swelling of the water-dispersible paper stock when a first layer is coated onto the surface of the water-dispersible paper stock in an aqueous solution during manufacturing. Summary of the Invention

[0004] Direct thermal recording media designed to be easily soluble or dispersible in water have many useful applications, such as removable labels for reusable containers or bottles, or as security substrates that can be easily and completely destroyed without the need for shredding. However, unless the image quality on such media is good enough to be reliably scanned and read by standard barcode readers, the number of potentially useful applications will remain limited. Thus, there is a need for alternative soluble or dispersible direct thermal recording media, particularly media that can produce reliably machine-readable barcode images when used in standard thermal printers operating at reasonable print speeds. Such alternative media or materials are preferably suitable for use in a variety of applications, such as labeling, facsimile, point-of-sale (POS) printing, tag printing, and pressure-sensitive labels. The alternative media also preferably produce high-quality images (including high-quality barcode images) when used in thermal printers with print speeds of at least 6, or 8, or even 10 inches per second (ips). A similar need exists for alternative soluble or dispersible inkjet printable recording media. The present inventors have developed a new family of water-dispersible recording materials or media that can be tailored to meet one, some, or all of these needs. The alternative recording media disclosed typically include a paper substrate, which can be water-soluble or water-dispersible, a printable layer, and a base coat between the substrate and the printable layer. The printable layer may be a thermally responsive layer, for example, containing a leuco dye and an acidic color developer, or an inkjet receiving layer. In some cases, the water-dispersible recording material may have two separate printable layers, for example, a thermally responsive layer and an inkjet receiving layer that can be imaged with a direct thermal printer.

[0005] The present inventors have discovered the advantages of using a water-insoluble binder material in a base coat together with other components, and have further found that such a binder material, when used in the appropriate amount, enables the resulting recording medium to be water-dispersible, i.e., breaks down with minimal agitation under the influence of water. Thus, the binder material of the base coat and the base coat itself are water-insoluble, but are tailored to ensure that the recording medium as a whole is water-dispersible. The base coat binder material is preferably a non-resin binder, a particulate binder, and / or a dispersion-derived binder, such as a latex. The use of such binder materials in carefully selected concentrations and with other elements results in a base coat that enables thermal printing of high-quality images on a thermally responsive layer at high printing speeds. Properties of the base coat that help promote this performance include its bulk or thickness, its relatively low thermal conductivity, and its relatively weak internal cohesion. Therefore, the present inventors specifically disclose a recording material or medium comprising a substrate, a thermally responsive layer carried on the substrate, and a base coat between the substrate and the thermally responsive layer. The substrate may be or include a water-soluble or water-dispersible paper. The base coat may include a binder that is water-insoluble, non-resinous, particulate, dispersion-derived, and / or latex.

[0006] The latex may be present in the base coat at a concentration of 10 to 30% by weight, or 15 to 20% by weight. The base coat may also include a hollow sphere pigment (HSP), which may be present in the base coat at a concentration of 20 to 50% by weight, or 30 to 50% by weight. The base coat may further include a second pigment selected from the group consisting of clay particles, precipitated calcium carbonate, and fumed silica, which may be present in the base coat at a concentration of less than 80% by weight, or in the range of 10 to 50% by weight. When the substrate contains pulp, refined pulp containing at least 88% by weight α-cellulose or less than 12% by weight hemi-cellulose may account for less than 15% by weight of the total pulp in the substrate, or alternatively, such refined pulp may account for 15-95% by weight of the total pulp in the substrate.

[0007] The present inventors also disclose a recording medium comprising a substrate, a printable layer carried on the substrate, and a base coat between the substrate and the printable layer, wherein the substrate comprises water-soluble or water-dispersible paper and the base coat comprises a water-insoluble binder. While the base coat is water-insoluble, such a recording material is water-dispersible. The printable layer may be a thermally responsive layer or an inkjet-receptive layer. A second printable layer may also be included, for example, when the first printable layer is thermally responsive and the second printable layer is inkjet-receptive. The inventors also disclose a number of related methods, systems, and articles. These and other aspects of the present disclosure will become apparent from the following detailed description. In no event, however, should the above summary be construed as limiting on the claimed subject matter, which subject matter is defined solely by the appended claims, as may be amended during prosecution. The articles, systems, and methods of the present invention are described in further detail with reference to the accompanying drawings. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional schematic view of a water-dispersible recording medium disclosed herein. [Figure 2] Figure 2 is an enlarged schematic view of a portion of the base coat used in the recording medium of Figure 1, in which like reference numerals refer to like elements. DETAILED DESCRIPTION OF THE INVENTION

[0009] Embodiments of the present invention include a new type of direct thermal recording material / media with a novel combination of features and functions, and methods for making the same. As a direct thermal recording medium, the product is adapted to change color in response to locally applied heat when fed, for example, through a direct thermal printer, to produce an image of a bar code, alphanumeric characters, graphic, or a combination thereof. The products of the present invention are preferably adapted to be water-dispersible, i.e., adapted to disintegrate or break apart (disperse) with minimal agitation when exposed to water. This is despite the fact that the product incorporates a water-insoluble base coat, and the binder of the base coat is water-insoluble. In other words, the binder, and the base coat as a whole, are not soluble in water. Although several water-dispersible direct thermal recording materials are already known, they generally suffer from low-quality image formation. That is, when known products are processed in a direct thermal printer at a normal printing speed (e.g., 6 inches per second (ips)) to print an image, the resulting image quality is generally low. The image quality is so low that it is almost completely impractical for barcode images, which require high image quality for reliable machine detection. The low image quality of known products is believed to be at least partially due to the product's outer surface being too rough or not smooth. The rough surface is a result of the component characteristics and manufacturing process, and water-dispersible base paper (water-dispersible paper) swells and roughens when a thermal layer is coated directly onto the base paper in an aqueous solution.

[0010] Thus, an additional feature of at least some embodiments of the recording material of the present invention that distinguishes it from existing products is the ability of the water-dispersible direct thermal recording material to produce high quality thermal images at normal and even high printing speeds (8-10 ips), enabling the formation of machine-readable barcode images. To achieve this high-speed, direct thermal printing capability, we employ a carefully designed base coat between the base paper (substrate) and the direct thermal layer (or other printable layer). In this regard, reference is made to the water-dispersible recording material 110 in FIG. 1. The recording material 110 may be prepared by coating various layers onto a water-dispersible or water-soluble base paper or carrier 112. The base paper 112 has sufficient physical strength and thickness to allow its operation and handling in a coating machine without undue tearing or breakage. The base paper 112 may thus be in the form of a web having two opposing major surfaces 112a, 112b. These surfaces are depicted as being uneven or rough, which worsens when the surfaces are wet. Applied directly to one of these surfaces 112a is a base coat 114. A printable layer 116, such as a direct thermal layer, is then applied over the base coat 114. An optional top coat 118 may be applied to the printable layer 116.

[0011] On the other side of the base paper 112, an optional adhesive layer 122, such as a pressure-sensitive adhesive (PSA) or other adhesive material, may be applied to the major surface 112b. The adhesive may be releasably supported or carried by an optional release liner 124. In the case of label products, after forming a thermal image on the direct-thermal layer 116, a user may remove the release liner 124 and apply the thus-printed label to a container or other suitable workpiece via the adhesive layer 122. After use, the label may be completely removed from the container by applying water with minimal or gentle agitation, causing the label to break and return to its original state on the container surface. In an exemplary embodiment, the base paper 112 may be or include water-dispersible paper. Depending on its thickness and composition, the paper of the base paper 112 may be thin and flexible, similar to common office paper, or thicker and stiffer, like cardboard or even boardstock. We use the term "paper" to encompass all such possibilities. The base paper 112 may have a thickness ranging from 2.5 mils to 20 mils, for example.

[0012] A suitable paper for use as the base paper 112 is Neenah Dispersa™ dispersible paper, available from Neenah, Inc. of Alpharetta, Georgia. The pulp from which the water-dispersible paper is made need not contain significant amounts of so-called refined pulp, which contains at least 88% by weight α-cellulose or less than 12% by weight hemi-cellulose. Such refined pulp may, for example, account for less than 15% by weight of the total pulp in the substrate. There are several product offerings under the Neenah™ Dispersa™ brand, such as product code 7630P0 (3.0-3.4 mil thick, said to be for labels), product code 7741P0 (14 mil thick, said to be for tags and paperboard), and product code 7742P0 (17 mil thick, said to be for tags and paperboard). Other water-dispersible papers suitable for use as the base paper 112 are available. Aquasol Corporation of North Tonawanda, New York, sells a 3-mil thick water-dispersible flexible paper under the product code ASW-35 / S. SmartSolve Industries (part of the CMC Group, Bowling Green, Ohio) sells several water-dispersible paper products, such as a 3-mil thick water-dispersible flexible paper under the product code IT117970.

[0013] Some of the commercially available water-dispersible papers mentioned above are described as "water-soluble" in their respective manufacturers' marketing literature. In some embodiments, the water-dispersible paper of the base paper 112 may contain an elevated amount of refined pulp as disclosed in U.S. Patent No. 8,877,678 (Koyama et al.). The refined pulp may comprise, for example, 15-95% by weight of the total pulp in the substrate. The base coat 114 is applied directly to one 112a of the major surfaces of the base paper 112. The base coat is specially formulated to provide a balanced combination of characteristics, including having sufficient bulk or thickness to smooth out any undulations or roughness in the major surface 112a of the base paper; having sufficient air content to provide good thermal isolation (low thermal conductivity); and having internal cohesion that is strong enough to remain intact during normal handling of the product, but weak enough to break down (disperse) when exposed to water after the underlying base paper 112 has dissolved or begun to dissolve or disperse or has begun to disperse.

[0014] The present inventors have discovered the advantages of using a water-insoluble binder material in a base coat together with other components, and have further discovered that such a binder material, when used in an appropriate amount, allows the resulting recording medium to be water-dispersible, i.e., breaks down with minimal agitation under the influence of water. Thus, the binder material of the base coat and the base coat itself are water-insoluble, but are adjusted so that the recording medium as a whole is water-dispersible. The binder material of the base coat is preferably a non-resin binder, a particulate binder, and / or a dispersion-derived binder, such as a latex. The use of such binder materials in carefully selected concentrations and with other elements results in a base coat that allows for the thermal printing of high-quality images on a thermoresponsive layer at high printing speeds. A properly prepared base coat 114 applied (directly) to the outer surface of the base paper 112 can substantially improve the imaging characteristics of the product, despite the increased surface roughness caused by applying a water-based coating to the base paper. The base coat 114 is preferably neither too thin nor too thick. Insufficient coat weight results in a base coat that does not adequately isolate the printable layer 116 from the base paper and simply conforms to the contours of the base paper. There is a practical limit to increasing the coat weight of the base coat 114, as more water can cause increased sheet instability and roughening during the coating procedure. Also, a base coat 114 that is too thick can cause the layer's internal cohesion to become too strong, inhibiting the layer's (and the product 110 as a whole) ability to quickly break down and disperse when exposed to water. Preferably, the base coat 114 is at least 2 micrometers thick and has a surface roughness of 1-5 lbs / 3300 ft. 2 (1.5 to 7.5 g / m 2 ), although other coat weights and thicknesses may be used if desired.

[0015] To increase the bulk as well as the air content of the base coat 114, the inventors have found it useful to incorporate hollow sphere pigments (HSPs), such as Ropaque™ pigments manufactured by Dow Chemical, into the base coat. The hollow polymer particles of HSPs can improve the bulk (thickness) of the base coat and smooth out the roughening effects of the surface of the base paper 112. The benefit of HSPs is that when the product is calendered during the manufacturing process (after the base coat is applied to the base paper and dried), the HSP particles can deform (under nip pressure) at the surface in contact with the calender surface, resulting in a smoother surface than can be produced using conventional pigments. HSP particles typically have an average diameter of a few micrometers or less, for example, in the range of 0.4 to 2 micrometers. HSP particles are not soluble in water.

[0016] Other pigments besides HSPs, such as calcined clay or other clay particles, and / or other particles with good bulk and water absorption properties, such as precipitated calcium carbonate (PCC) or fumed silica, can also be used in the base coat 114 and are preferably used, but by themselves do not typically provide the bulk necessary to overcome roughening of the base paper. Such other pigments may not or need not be soluble in water. A mixture of HSPs and one or more other pigments in the base coat 114 can provide a good balance of improved coverage, smoothness, and sheet integrity, enabling direct thermal printing of machine-readable barcodes at high (and normal) speeds.

[0017] Another important design consideration and aspect of the present invention is the binder material to be used in the base coat 114. Conventional wisdom would suggest that the binder material used in the base coat 114 of the water-dispersible recording material 110 should be water-soluble. However, the inventors have found that water-soluble binder materials tend to increase the thermal conductivity of the base coat and reduce its thermal insulating properties. Because the print quality of direct thermal images is improved by insulating the direct thermal layer from the base paper as much as possible, reduced insulation reduces image quality. In contrast, the inventors' preferred binder materials, which are not water-soluble, provide fast-drying solutions and, when used in carefully controlled concentrations, offer improved thermal insulation over water-soluble binders without interfering with the water-dispersible nature of the substrate. Preferred binder materials for the base coat 114 include those that are water-insoluble, non-resinous, particulate, and / or dispersion-derived. An exemplary such binder material is latex. Alternative or additional binder materials may include cooked starch, polyvinyl alcohol (PVA), and AQ™ polymers available from Eastman Chemical Company.

[0018] Carefully adjusting this binder concentration balances the need to hold the pigment particles together so that they can withstand normal handling of the material 110, the need to provide numerous air pockets and voids throughout the base coat 114 to increase thermal insulation, and the need to provide a relatively weak internal cohesion of the base coat so that it will easily fracture when the underlying substrate 112 begins to disintegrate or dissolve under the action of water. A schematic diagram of such a balanced or adjusted situation is shown in the enlarged view of Figure 2. Here, a representative but small portion 230 of the base coat 114 is composed of HSP particles 232, particles 234 of a second pigment such as calcined clay, and binder particles 236 such as latex. The binder particles 236 are numerous enough to adequately hold the pigment particles together, yet sparse enough to maintain numerous air pockets and voids between the particles for adequate thermal insulation. To provide the desired balance of properties, the latex or other suitable water-insoluble binder is preferably present in the base coat 114 at a concentration of 10 to 30%, or 15 to 20%, by weight. The HSP is preferably present in the base coat 114 at a concentration of 20 to 50%, or 30 to 50%, by weight. The calcined clay or other suitable second pigment is preferably present in the base coat at a concentration of less than 80%, or in the range of 10 to 50%, by weight.

[0019] Returning to FIG. 1 , a printable layer 116 is then coated over the base coat 114. In some embodiments, the printable layer 116 is or includes a direct thermal layer and may be of otherwise conventional design. For example, the direct thermal layer may include a combination of a leuco dye or other basic color-forming material and an acidic color-developing material in a solid matrix or binder. See, e.g., Baum No. 3,539,375, Blose et al. No. 3,674,535, Blose et al. No. 3,746,675, Baum No. 4,151,748, Hanson et al. No. 4,246,318, or Glanz No. 4,470,057. Other known types of direct thermal layers may alternatively be used, such as those disclosed in U.S. Patent Application Publication No. 2019 / 0291493 (Fisher et al.), "Direct Thermal Recording Media Based on Selective Change of State." Direct thermal layers containing perforated particles and other components therein, such as those disclosed in U.S. Patent Application Publication No. 62 / 905815, filed September 25, 2019, "Direct Thermal Recording Media with Perforated Particles," may also be used.

[0020] In other embodiments, the dispersible recording material 110 may not be adapted for direct thermal printing, but instead for other printing techniques, such as inkjet printing, and in such cases, the printable layer 116 may be or include an inkjet receiving layer of known design. 1, an optional protective topcoat 118 can be applied to the printable layer 116 to improve durability against handling, such as scratches, while preserving the product's water dispersibility and high speed barcode (high image quality) thermal printing characteristics. The topcoat 118 can be of conventional design, including, for example, binders such as modified or unmodified polyvinyl alcohol, acrylic binders, crosslinkers, lubricants, and fillers such as alumina trihydrate and / or silica. The recording material 110 can be used as a self-adhesive label, as shown, by adding an otherwise conventional adhesive layer 122 and release liner 124. The pressure-sensitive adhesive (PSA) or other adhesive used in the adhesive layer is preferably water-dispersible or water-soluble so that the entire label can be easily washed off and completely removed by the user after use, for example, after direct thermal printing, from the labeled workpiece. [Example]

[0021] Example 1 A recording material was prepared and tested, as generally shown in Figure 1, but without layers 118, 122, and 124. The substrate paper 112 used was the above-referenced Neenah Dispersa™ dispersible paper, product code 7630P0. A base coat 114 was then applied to major surface 112a at a coat weight of 6 grams per square meter (gsm). The base coat formulation was as follows: Wed: 40.5 parts Mineral Pigment 1A: 21.5 parts HSP@19.5% solids in water: 26.3 parts Latex @ 50% solids in water: 11.5 parts Mineral Pigment 1A was calcined clay (Kaocal from Thiele Kaolin Company). The HSP used was Ropaque TH-2000AF from Dow Chemical, nominally having an average diameter of 1.6 micrometers. The latex used was SBR latex (LIGOS KX4505 from Trinseo LLC.).

[0022] After drying, a printable layer 116 was applied to the exposed surface of the basecoat. The printable layer was a direct thermal layer of conventional design containing a combination of a leuco dye and an acidic developer in a matrix. The leuco dye used was ODB-2 (CAS No. 89331-94-2, chemical name spiro(isobenzofuran-1(3H),9'-(9H)xanthene)-3-one,6'-(ethyl(4-methylphenyl)amino)-3'-methyl-2'-(phenylamino)-), and the developer was TGSH (chemical name bis(3-allyl-4-hydroxyphenyl)sulfone). The resulting dispersible direct thermal recording medium was imaged with a barcode pattern in a Zebra™ thermal printer, model 140-401-0004, at speeds of 6, 8, and 10 ips, using the factory default heating settings. The resulting barcode images were then tested for ANSI values ​​as a measure of image quality. The ANSI values ​​were measured using a TrueRemote™ Webscan™ Barcode Verifier, model TC-843, operating at a wavelength of 650 nm. Samples printed at each of the three print speeds all tested with an ANSI value greater than 1.5, meaning the barcode was reliable for machine reading. Example 1 was also tested for its response to liquid water. When a gentle stream of water was directed at the printed sample, the sample was found to rapidly and completely disintegrate and disperse.

[0023] Example 2 A recording material similar in some respects to Example 1 was prepared, having only layers 112, 114, and 116 (see FIG. 1). The base paper 112 used was the water-dispersible paper product sold by SmartSolve Industries, product code IT117970, referenced above. This base paper had a thickness of 3 mils. A base coat 114 was then applied to major surface 112a at a coat weight of 6 gsm and allowed to dry. The base coat formulation was substantially as follows: Wed: 32.1 parts Mineral Pigment 1A (see above): 24.5 parts HSP@19.5% solids in water: 29.3 parts Latex @ 50% solids in water: 12.8 parts A printable layer 116 was then applied to the exposed surface of the basecoat. The printable layer had a coat weight of 3 gsm and was again a direct thermal layer of conventional design containing ODB-2 and TGSH. The resulting dispersible direct thermal recording medium was imaged with a barcode pattern as in Example 1 (Zebra™ printer, default heat setting, print speeds of 6, 8, and 10 ips). The resulting barcode image was then tested for ANSI values ​​as in Example 1. The resulting ANSI values ​​at each of the three print speeds were all greater than 1.5. Example 2 was also tested for its response to liquid water: when a gentle stream of water was directed at the printed sample, the sample was found to rapidly and completely disintegrate and disperse.

[0024] Example 3 A recording material similar in some respects to Examples 1 and 2 was prepared, having only layers 112, 114, and 116 (see FIG. 1). The substrate paper 112 used was the same water-dispersible paper product used in Example 2. A base coat 114 was then applied to major surface 112a at a coat weight of 3 gsm and allowed to dry. The base coat formulation was substantially as follows: HSP@19.5% solids in water: 88.6 parts Latex @ 50% solids in water: 8.3 parts Precipitated calcium carbonate: 1.9 parts Ground calcium carbonate: 1.2 parts A printable layer 116 was then applied to the exposed surface of the basecoat. The printable layer had the same composition and coat weight as the printable layer of Example 2. The resulting dispersible direct thermal recording medium was imaged with a barcode pattern (Zebra™ printer, default heat setting, print speeds of 6, 8, and 10 ips) as in Examples 1 and 2. The resulting barcode image was then tested for ANSI values ​​as in Examples 1 and 2. The resulting ANSI values ​​at each of the three print speeds were all greater than 1.5. Example 3 was also tested for its response to liquid water, and when a gentle stream of water was directed at the printed sample, the sample was found to rapidly and completely disintegrate and disperse.

[0025] Example 4 A recording material was prepared similar in some respects to Examples 1-3, but with a topcoat layer 118 (see FIG. 1) added over the printable layer 116. The base paper 112 used was the same water-dispersible paper product used in Examples 2 and 3. A basecoat 114 was then applied to the major surface 112a at a coat weight of 3 gsm and allowed to dry. The basecoat formulation was substantially as in Example 3. A printable layer 116 was then applied to the exposed surface of the basecoat. The printable layer had the same composition and coat weight as the printable layer of Examples 2 and 3.

[0026] Next, a topcoat layer 118 was applied to the exposed surface of the printable layer. The topcoat layer had a coat weight of 3 gsm and its composition was adjusted to be inkjet receptive. Its formulation was substantially as follows: Aluminum hydroxide @ 40% solids in water: 33.7 parts Polyvinyl alcohol (PVA) @ 9.0% solids in water: 31.3 parts Wed: 10.9 parts Crosslinker: 9.4 parts Amorphous silica @ 30% solids in water: 7.8 parts BASF Catiofast 159A: 4.7 parts Printhead lubricant (Hildorin H-526): 2.1 parts Thus, the topcoat can also be considered a second (or separate) printable layer, allowing inkjet printing onto its own surface while simultaneously allowing direct thermal printing of images on the underlying printable layer 116.

[0027] The resulting dispersible recording material was imaged with a barcode pattern (through layer 116 through layer 118) (Zebra™ printer, default heat setting, print speeds of 6, 8, and 10 ips) in the same manner as in Examples 1-3. The resulting barcode images were then tested for ANSI values ​​in the same manner as in Examples 1-3. The slowest print speed (6 ips) resulted in an ANSI value greater than 1.5, while the faster print speeds (8 and 10 ips) both had ANSI values ​​less than 1.5. An HP Photosmart™ inkjet printer, model 7960, was used to print Example 4 on its topcoat. The printer's factory calibration page was a pattern or image that was printed and evaluated to determine the inkjet suitability of the sample. The evaluation showed that the printed sample had acceptable image quality and showed no evidence of ink smearing or line bleeding. Example 4 was also tested for its response to liquid water. When a gentle stream of water was directed at the printed sample, the sample was found to completely and quickly disintegrate and disperse, although not as rapidly as in Examples 1-3.

[0028] In the foregoing detailed description of the present disclosure, reference is made to the accompanying drawings which form a part hereof, and which show, by way of illustration, how embodiments of the present disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments of the present disclosure, and it should be understood that other embodiments may be utilized and that process and / or structure changes may be made without departing from the scope of the present disclosure. Unless otherwise indicated, all numbers expressing quantities, measured properties, and equivalents used in the specification and claims are to be understood as modified by the term "about." Accordingly, unless otherwise indicated, the numerical parameters set forth in the specification and claims are approximations that may vary depending upon the desired properties sought to be obtained by one of ordinary skill in the art utilizing the teachings herein. Without limiting 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.

[0029] The use of relational terminology, such as "top," "bottom," "upper," "lower," "above," "below," and the like, to describe various embodiments is used merely as a matter of convenience to facilitate the description of some embodiments herein. Despite the use of such terminology, the present disclosure should not be construed as being limited to any particular orientation or relative position, but rather should be understood to encompass embodiments having any orientation and relative position in addition to the embodiments described above. Various modifications and alterations of the present invention will become apparent to those skilled in the art without departing from the spirit and scope of the present invention, and the present invention is not limited to the exemplary embodiments described herein. The reader should assume that features of one disclosed embodiment can be applied to all other disclosed embodiments, unless otherwise indicated. Another aspect of the present invention may be as follows. [1] A substrate including water-soluble or water-dispersible paper, a printable layer carried on the substrate, and A recording material comprising a base coat between the substrate and the printable layer, the base coat comprising a water-insoluble binder. [2] The recording material according to [1] above, wherein the printable layer is a thermoresponsive layer. [3] The recording material according to [1], further comprising a topcoat layer disposed on the printable layer. [4] The recording material according to [3] above, wherein the top coat layer is inkjet print-receptive. [5] The recording material according to [1] above, wherein the printable layer is an inkjet receiving layer. [6] The recording material according to [1], wherein the base coat is water-insoluble but the recording material is water-dispersible. [7] The recording material according to [1], wherein the water-insoluble binder is non-resin, or granular, or derived from a dispersion. [8] The recording material according to [1], wherein the water-insoluble binder contains latex. [9] The recording material according to [1], wherein the water-insoluble binder is latex, and the latex is present in the base coat at a concentration of 10 to 30% by mass.

[10] The recording material according to [9], wherein the latex is present in the base coat at a concentration of 15 to 20% by mass.

[11] The recording material according to [1], wherein the base coat contains a hollow sphere pigment (HSP).

[12] The recording material according to

[11] , wherein the HSP is present in the base coat at a concentration of 20 to 50% by mass.

[13] The recording material according to

[12] , wherein the HSP is present in the base coat at a concentration of 30 to 50% by mass.

[14] The recording material according to

[11] , wherein the base coat contains a second pigment selected from the group consisting of clay particles, precipitated calcium carbonate, and fumed silica.

[15] The recording material according to

[14] , wherein the second pigment is present in the base coat at a concentration of less than 80% by mass.

[16] The recording material according to

[15] , wherein the second pigment is present in the base coat at a concentration of 10 to less than 50% by mass.

[17] The recording material according to [1], wherein the substrate contains pulp, and the refined pulp containing at least 88% by mass of α-cellulose or less than 12% by mass of hemi-cellulose accounts for less than 15% by mass of the total pulp in the substrate.

[18] The recording material according to [1], wherein the substrate contains pulp, and refined pulp containing at least 88% by mass of α-cellulose or less than 12% by mass of hemi-cellulose accounts for 15 to 95% by mass of the total pulp in the substrate.

[19] The recording material described in [2] above, which is configured to be used in a direct thermal printer to produce a heat-induced image, and the print quality of the recording material when used in such a direct thermal printer at a printing speed of 6 inches per second is characterized by an ANSI value of at least 1.5.

[20] The recording material according to

[19] , wherein the print quality of the recording material when used in such a direct thermal printer at a printing speed of 10 inches per second is characterized by an ANSI value of at least 1.5.

Claims

1. a substrate comprising water-soluble or water-dispersible paper; a printable layer carried on a substrate; and a base coat between the substrate and the printable layer, the base coat comprising a water-insoluble binder that is a latex and that is water-insoluble; A recording material comprising the compound (I) and being water-dispersible.

2. 2. The recording material according to claim 1, wherein the base coat contains a pigment.

3. 2. The recording material of claim 1, wherein the base coat comprises hollow sphere pigments (HSP).

4. 2. The recording material according to claim 1, wherein the printable layer is a thermoresponsive layer.

5. a topcoat layer disposed over the printable layer The recording material according to claim 1 , further comprising:

6. 2. The recording material according to claim 1, wherein the printable layer is an inkjet receiving layer.

7. 2. The recording material according to claim 1, wherein the latex is present in the base coat at a concentration of 10 to 30% by weight.

8. 2. The recording material according to claim 1, wherein the base coat comprises hollow sphere pigments (HSPs), and the HSPs are present in the base coat at a concentration of 20 to 50% by weight.

9. the base coat comprises a second pigment selected from the group consisting of clay particles, precipitated calcium carbonate, and fumed silica; and 9. The recording material according to claim 8, wherein the second pigment is present in the base coat at a concentration of 10 to 50% by weight.

10. 5. The recording material of claim 4, configured for use in a direct thermal printer to produce heat-induced images, wherein the print quality of the recording material when used in such a direct thermal printer at a print speed of 6 inches per second is characterized by an ANSI value of at least 1.

5.

11. 2. The recording material according to claim 1, wherein the substrate contains pulp, and the refined pulp containing at least 88% by mass of α-cellulose or less than 12% by mass of hemi-cellulose accounts for less than 15% by mass of the total pulp in the substrate.

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