TW201825255A - Release webs and textured products - Google Patents

Abstract

The present disclosure features processes and equipment for manufacturing materials that have a textured surface formed by applying a first texture to a curable coating, curing the coating, and then embossing a second, different texture over the first texture. The disclosure also features textured materials, including both release webs for use in replicative casting processes and finished products in sheet, board, plate or web form.

Description

Release template and article imparted by it

The surface texture (for example, a three-dimensional pattern) can be imparted to the template through a process in which a curable coating is applied to the template, a curable coating texture is imparted through a replication surface (eg, a metal engraving roll), and the radiation is passed through the template. The coating is cured while being in contact with the roll.

The templating material produced by this process can be used as a release stencil in subsequent processes, such as forming (eg, casting) a plastic film on a release stencil or against a release stencil, and after the plastic material is cooled or cured, and removed. Template separation. The release stencil provides a surface from which the cured plastic material can be easily separated and imparts a texture to the release surface of the plastic material. For example, by forming a plastic sheet on a release template having a textured surface, a desired textured surface can be provided on the surface of the plasticized material, the textured surface on the release template being the desired textured surface. Mirroring.

Techniques for producing surface effects in release coatings on release liners used in a casting process are disclosed in U.S. Patent Nos. 4,289,821, the disclosure of which is incorporated herein by reference. One disclosed method includes applying a coating of an electron beam radiation curable material to one surface of a template substrate, pressing a coated side of the substrate against a replication surface, such as a metal engraving roll, and irradiating the coating with electron beam radiation. The coating is cured and the cured coating adhered to the substrate is then peeled off from the replication surface. Using these methods, the replicated surface can be replicated in the cured coating with substantially 100% fidelity. Other replication casting methods are disclosed in U.S. Patent No. 6,355,343 and U.S. Patent No. 7,964,243, the disclosure of each of

The copy casting process can be used to form very fine, even nanoscale textures. One embodiment of a microscale texture is referred to in the art as "Sharklet." Sharklet texture can be applied to plastic sheet products to provide a structured surface that prevents bacterial growth from being provided to the article. The microscale texture of the surface replicates as shark skins, arranged in a diamond pattern with millions of ribs. Sharklet materials are discussed in a wide variety of applications, for example, in U.S. Patent No. 7,650,848 and U.S. Pat. This material is important in providing non-toxic bioadhesion control and antifouling properties and has been proposed for use in the medical device industry. Other microscale textures include lenticular textures, drag reduction textures (eg, Riblet features), and cube corner textures that produce reflective surfaces.

Nanoscale textures include diffraction gratings, hydrophobic surfaces (eg, lotus leaf-like surfaces with micron and nanoscale structures on the surface that minimize adhesion of droplets to the surface) and laser interference rainbow patterns, Shows the reflected light as the color of the visual spectrum. One embodiment of a nanoscale texture is a diffraction grating having a series of raised ridges that are about 400 nm wide, about 800 nm apart, and about 100 nm deep.

A feature of the invention is a process and apparatus for making a material having a textured surface by applying a first texture to a curable coating and curing the coating, and then imprinting on the first texture different from the first texture The second texture. The disclosure further relates to textured materials, including release stencils for replica casting processes and finished articles in the form of sheets, strips, strips or sheets.

In some embodiments, the methods disclosed herein can be used to impart material texture to micron, nanoscale (eg, Sharklet materials) to macroscopic scale (and thus visually observable). This can enhance the appreciation of the material and provide other advantages such as improved wear resistance and feel.

In one aspect, the invention features a release liner for a replica casting of a curable system. The release liner comprises a substrate and a coating disposed on at least one surface of the substrate, the coating having a surface effect that replicates during casting. Surface effects include a first three-dimensional texture on a micro or nano scale and a second three-dimensional texture on a macro scale.

In some embodiments, the release template can include one or more of the following technical features.

The second three-dimensional texture may be post-embossed on the first three-dimensional texture during manufacture of the release template. The first texture may be composed of a diffraction grating, a hydrophobic surface texture, a laser interference rainbow pattern, and combinations thereof; or a lenticular lens texture, a drag reduction texture, a cube corner texture, and combinations thereof. In some embodiments, the second texture has a feature depth of about 50 to 300 microns. The first texture may have a feature length of from about 1 to 100 microns, a feature width of from about 1 to 10 microns, a feature pitch of from about 1 to 10 microns, and a feature depth or height of from about 1 to 10 microns.

In another aspect, the invention features a method comprising applying a coating to a flexible substrate and imparting a first three-dimensional texture of the coating on a micro or nano scale and a second three-dimensional texture on a macro scale To form a release template with a textured surface.

In some embodiments, the method can include one or more of the following features.

The method may further comprise curing the coating after imparting the first texture and prior to imparting the second texture. The imparting the second three-dimensional texture may include imprinting the cured coating. At least one texture can be applied by clamping the coating against the surface of the engraving roll. For example, the cured coating can be imprinted by pressing the cured coating against a heated replication surface. In some embodiments, the replication surface can be heated to a temperature greater than the glass transition temperature of the cured coating.

The method may further comprise casting a polymeric film on the release liner, and in some embodiments, laminating a sheet of material such as a fabric, sheet, paper or foil onto the cast polymeric film. The polymer film may comprise a polyurethane resin.

In another aspect, the disclosure features an article comprising a flexible template having a textured surface comprising micron, nanoscale features, and macroscale features, the micro or nanoscale features and The macro scale features are placed on the same area of the template.

In some embodiments, an article of manufacture can include one or more of the following features.

The flexible template may comprise a textured polymer layer such as polyurethane, thermoplastic such as polypropylene or enamel. The article may comprise a resin mold. In some cases, the flexible template further comprises a sheet of material laminated to the textured polymer layer, such as a fabric, board, paper or foil.

In another aspect, the present disclosure features a method of making an article having a textured surface, the method comprising mechanically imprinting a three-dimensional texture of a macroscopic scale on a surface of a template having a microscopic or nanoscale three-dimensional texture.

Another feature of the present disclosure is a method comprising: (a) casting a resin on a textured release template having a macro-scale texture and a micro or nano-scale texture disposed on the same surface of the template to form a textured (b) forming a mold comprising a textured tantalum replica template; (c) using a mold to form a nickel sleeve; and (d) utilizing a nickel sleeve as a replication surface to impart a macroscopically to the second release template Micron or nanoscale structure.

As used herein, the terms "texture" and "texture surface" include very fine textures, for example including textures having a topography that is lower than the wavelength of light. The textures discussed herein are predetermined textures, that is, textures that are intentionally imparted to the surface, not just the natural appearance of the surface, surface contamination, etc., which are inherently present on any surface.

The term "feature spacing distance" as used herein refers to the distance between adjacent features of a three-dimensional texture. The feature separation distance can be observed and measured using a confocal microscope or a scanning electron microscope (SEM).

The term "nanoscale" as used herein refers to a feature having a feature scale of less than 1000 nm.

The term "micro-scale" as used herein refers to a feature having a feature scale of less than 50 [mu]m.

The term "macro-scale" as used herein refers to a feature that is discernible by the naked eye.

"Web" as used herein in the singular and plural forms includes continuous templates and discrete sheets.

All are by weight unless otherwise stated.

Other features and advantages of the present invention will be apparent from the description and appended claims.

The process described herein involves post-embossing the texture on the underlying fine-scale texture. In some cases, the features of the underlying texture are invisible to the naked eye, while the features of the post-embossed texture can be seen with the naked eye. An example of such an arrangement is schematically illustrated in Figures 1 and 1A, wherein the release template 10 includes a substrate 12 carrying a coating 14. Coating 14 includes microscale 16 and macroscale 18. As shown in FIG. 1, the substrate 12 may be deformed by an imprint process imparted to the macroscale 18, or as shown in FIG. 1A, the macroscale 18 may only affect the surface of the substrate. Although the features are evenly spaced in Figures 1 and 1A, other textures that may employ micro-scale and/or nano-scale features are irregularly spaced apart.

In some embodiments, the underlying texture is a micro or nano scale texture, such as a functional texture such as a Sharklet texture, and the post imprint texture is a larger scale, such as a macro scale texture. As will be discussed below, these processes can be used to form a release template having two superimposed textures, or can be used to post-emboss a textured article, such as a paper or plastic template having a textured surface. For example, the textured article can be a printed decorative paper having a Sharklet micro-scale pattern, followed by post-embossing the substrate with a macroscopic scale such as a "woodcut" pattern.

Macroscale textures can be applied to micron or nanoscale textured articles that would otherwise be visually unattractive and have no aesthetic appearance that was originally expected. For example, the macro scale texture can be leather or wood grain, or other visually appealing texture.

Adding macroscale textures tends to hide seams in micron or nanoscale textures, which may be produced by processes used to create replicated surfaces that acquire micron or nanoscale textures. For example, a primary micro or nano scale pattern can be created on a flat main shim and the pattern on the shim is transferred to a roll that serves as a replication surface. A finite scale planar pattern from the primary shim is placed over the surface to give a relatively continuous pattern around the circumference and length of the roll. During this tiling process, a visible seam is formed between each pattern area. These seams are aesthetically more objectionable, so it is advantageous that the post-embossing minimizes the visibility of the seam.

In the case of a texture having, for example, Sharklet, the macro-scale pattern can also reduce the visual intensity of the iridescent appearance of the finished article made using the release template, which may exhibit a texture such as iridescence due to the use of a diffraction grating.

Surprisingly, the post-embossing process does not adversely affect the fidelity of micron or nanoscale textures and therefore does not generally negatively impact the functional properties provided by micron or nanoscale textures. For example, if the underlying texture is designed to impede bacterial growth, this property will remain in the post-imprinted article.

The macro-scale texture can also improve the durability and wear resistance of the finished product by preferentially abrading the raised areas of the macro-scale texture and protect the underlying micro or nano-scale texture.

Texture template

Embodiments of micron-scale textures include the Sharklet pattern described in U.S. Patent 7,145,709 B2. These patterns consist of a series of ridges that can be above or below the plane of the substrate coating. The micron feature scale can range from 0.5 to 50 microns. In some embodiments, the feature length can be from about 1 to 50 microns, the feature width can be from about 1 to 10 microns, the feature pitch can be from about 1 to 10 microns, and the feature depth or height (distance perpendicular to the plane of the substrate) can It is about 1 to 10 microns. In one embodiment, the length of the ridge varies between 4 and 16 microns, with a width of 2 microns, a pitch of 2 microns, and a height/depth of 2 to 3 microns. In another embodiment, the length of the ridge varies between 20 and 80 microns and has a width of 10 microns, a pitch of 2 microns, and a height/depth of 2 to 3 microns. For both examples, the angle of the sidewall of each feature is less than 85 degrees. In some embodiments, the angle of the sidewalls is from about 10 to 90 degrees, such as from about 50 to 85 degrees. If the angle of the sidewall is greater than about 85 degrees, the peel force of the cured coating from the replication surface (eg, engraved roll) can be very high.

Nanoscale textures can have feature scales (length, width, and depth/height) in the range of 10 to 999 nm.

In some embodiments, the micro or nano scale texture may include features in the positive and negative z directions, as an example, such as certain Sharklet materials.

The macro-scale texture can be, for example, any of a number of textures on Sappi / Warren release papers. These Sappi / Warren release papers are available under the trademark ULTRACAST® or under the trade name Classic, which is owned by SD Warren d/b/a Sappi North America. production. An example of a macro scale pattern is a replica of natural leather particles having a characteristic depth of about 50 to 300 microns. Any other desired macro scale texture can also be used.

In addition to the macroscale features, the post-embossed texture may include microscale features that contribute to the tactile or aesthetic properties of the texture (eg, surface gloss/brightness) and are invisible to the naked eye.

Process for making a release template

An example of a process 100 for making a release liner and a finished article made from a release liner is illustrated in Figures 2 and 2A.

Referring to Figure 2, process 100 includes applying a coating to the surface of a stencil substrate that will be a release stencil, or to a replication surface that will be used to apply a micro or nanoscale texture to the coating (step 110). For example, the coating can be applied to the substrate before it reaches the replication surface; or the coating can be applied to the replication surface and the coating transferred to the substrate as the substrate is pressed against the replication surface.

The substrate template can be any flexible sheet substrate such as paper, metal foil and plastic film. In some embodiments, the substrate template is preferably a paper having an undercoat to prevent excessive penetration of the coating composition. The replication surface can be, for example, the surface of an engraving roll, the surface of a texture template conveyed from a supply roll and wound on a take-up roll, or any other suitable textured surface such as a textured sleeve, belt, cylinder or plate.

The substrate template is clamped onto the replication surface to produce a coated template having a surface opposite the replicated surface (step 120). The coated template is then passed through a curing station to cure the coating to form a textured template (step 130). The replication surface remains in contact with the coated template during curing and the textured template is peeled from the replication surface after curing. The curing station may comprise a radiation delivery device such as a UV lamp or an electron beam device. The coating composition is selectively cured using a device in the curing station. Typically, no heat or pressure is applied during this step.

The textured fabric is then subjected to a post-embossing having a larger scale (e.g., macroscopic scale) texture using a second replicated surface (step 140). As illustrated in detail in FIG. 2A, the post-embossing step can be performed, for example, by passing the template 139 through the nip 141, wherein the textured surface of the template is pressed against the heated engraving roll (or other replicated surface) 142, For example in a hydraulic press. The nip defined by the engraving roll 142 and the elastic back roll 143 is pressurized to a desired pressure. The engraving roll can be heated, for example, by steam or oil. Heat and pressure are applied at the nip during the mechanical embossing step to impart a surface texture of the engraving roll to the text template. The heat and pressure selectively applied in a particular process will be discussed in the Process Parameters section below. The post-imprint template leaving the nip is ready for use as a release template.

After post-embossing, the finished release liner can be used to form the desired final article, such as by casting a plastic film on the release liner (step 150).

Coating composition

In general, suitable coating compositions are capable of being mechanically imprinted in a post-imprint process after curing and are capable of withstanding the expected conditions of a subsequent replication casting process without suffering unacceptable damage. The composition of the coating composition for a particular process will depend on a number of factors, including the depth of the macroscale pattern to be applied, the post-imprint conditions (e.g., temperature and pressure), and the chemicals to be used in the replication casting process.

The radiation curable acrylate composition has chemical resistance upon curing and excellent flexibility when used as a coating, and thus is a preferred choice in many embodiments.

In some embodiments, the coating composition comprises a monofunctional acrylate monomer to impart release properties and flexibility to the cured coating, and as a diluent, a multifunctional acrylate monomer for crosslinking, in some cases The acrylated oligomer provides flexibility to the cured coating.

In some embodiments, the ratio between monofunctional and multifunctional acrylates is from about 15:85 to 85:15. In some embodiments, the monofunctional acrylate material provides at least 15%, such as at least 25%, 35%, 45%, 55%, 65%, or 75% of the total acrylate material in the coating composition. In some embodiments, from about 15% to about 85%, or from about 33% to about 66%, of the total acrylate material is a monofunctional acrylate monomer. The chain length of the monofunctional acrylate material also affects the release properties of the coating composition. In some embodiments, the molecular weight is from about 120 to 380, such as from about 128 to about 212, or from about 212 to 324.

Monofunctional monomers include, for example, acrylic acid, N-vinyl pyrrolidone, (ethoxyethoxy)ethyl acrylate, and isodecyl acrylate.

Polyfunctional monomers include, for example, trimethylolpropane triacrylate (TMPTA), propoxylated glycerin triacrylate (PGTA), tripropylene glycol diacrylate (TPGDA), and dipropylene glycol diacrylate (DPGDA). Preferably, the multifunctional monomer is selected from the group consisting of TPGDA, TMPTA, and mixtures thereof.

Acrylic oligomers include, for example, acrylated urethanes, epoxies, polyesters, acrylates, and decanes. In some embodiments, a urethane acrylate is preferred. Acrylic oligomers contribute to the mechanical properties of the coating. The inclusion of an acrylated oligomer can impart toughness and flexibility to the cured formulation, which can help the cured coating to withstand post-embossing without cracking. Acrylate oligomers are commercially available, for example, from Allnex Corporation under the trade name EBECRYL® UV/EB curable resins.

As an example, a composition that can be used to form the release coating used in the methods described herein can include (before curing) 20-50% acrylated oligomer, 15-35% monofunctional monomer, and 20 -50% of a polyfunctional monomer.

The composition may include a reactive or non-reactive siloxane such as an amino-functional siloxane as a release agent which aids in the release of the cured coating from the replication surface if the coating is cured while in contact with the replication surface.

The coating composition may include materials other than acrylic functional materials such as viscosity control additives such as colloidal cerium oxide or volatile solvents, or surface texture materials such as starch granules or cerium oxide. If UV curing is used, the composition will typically include a photoinitiator. In addition, filler materials such as conventional paper coating dispersants may be included to reduce the cost of the coating. However, the amount of acrylic functional material in the coating composition must be sufficient to provide a continuous polymeric layer in the area where it is coated. Preferably, the acrylic functional material comprises at least about 30% by weight of the total coating composition, more preferably at least about 40%.

Replicative Surfaces

The replication surface is typically disposed on a rotating cylindrical member, such as a roller or drum having a patterned or engraved sleeve or surface, but may also be disposed on a panel, tape or textured release template.

A first replication surface for imparting a first texture to the micron or nanometer scale is typically disposed on a metal roll or sleeve and may use lithography, ion deposition, laser interference or other to impart micro or nanoscale features to the surface. The technique forms the first replicated surface. Other types of replicated surfaces can be used, including textured release liners, strips, tapes, and the like, but it is often necessary to fabricate the body using techniques that are capable of forming very fine (e.g., micron or nanoscale) features.

The second replication surface can be produced using a variety of techniques, such as those well known in the art of embossing. The second replicated surface is typically selected to have a surface that can withstand the process parameters used in the post-imprint process.

Process parameter

The temperature of the stencil (embossing temperature (Te)) at the nip during the post-embossing step may be important, in particular to allow for accurate, high fidelity reproduction of the post-embossed texture. For example, conventional techniques such as passing steam or/or hot oil through or through a nip roll to heat one or both of the nip rolls can be used to heat the stencil as it passes through the nip. The preferred templating temperature for a particular process will depend on various factors including: the composition of the coating, the thickness of the coating, the kinetic parameters of the nip, the speed of travel of the stencil through the nip, and the depth of texture after embossing. The templating temperature is sufficiently higher than the glass transition temperature (Tg) of the crosslinked coating to achieve sufficient coating flow to allow for accurate imprinting. The extent to which the template temperature exceeds Tg can be empirically based on the above factors. In some embodiments, the templating temperature is from about 100 to 200 °F, such as from about 140 to 170 °F, depending on the equipment available, and temperatures of, for example, up to 500 °F or higher can also be used.

The templating temperature is usually lower than the temperature of the heated nip. In some embodiments, the templating temperature after exiting the heated nip is about 60 to 100 °F lower than the surface temperature of the heated nip rolls. This temperature difference can vary depending on various factors that affect heat transfer.

In general, the stencil temperature should be high enough to allow uniform, high fidelity macro size patterns to be embossed edge to edge over the entire stencil. If the coating used is prone to cracking, a sufficiently high temperature can also help to minimize cracking of the coating during post-embossing.

High hardness crosslinked coatings having a relatively high Tg (e.g., 120 °F) may be more susceptible to cracking during post imprinting. In some cases, to minimize or avoid cracking, it may be desirable to impart greater flexibility to the coating, such as by changing the coating composition or reducing the thickness of the coating, and/or increasing the post-embossing temperature.

The pressure applied at the nip is also important to obtain a good post-embossed texture. If the pressure is too high, in some cases this may result in unevenness of the embossing on the opposite side of the width of the stencil. If the pressure is too low, the characteristic depth of the desired embossed texture may not be obtained. In some embodiments, the nip pressure is at least 1000 pounds per linear inch (PLI), such as from about 1000 to 2000 PLI. The appropriate pressure is the same as that used in standard macro size imprinting methods; it appears that the pressure used does not affect the underlying micro or nanoscale pattern.

In some cases, the nip includes an elastic back roll that can have a Shore D hardness of, for example, about 80 to 90.

In some embodiments, the coating has a coat weight of from about 10 to 15 g / m ² . The stiffness of the coating is proportional to the thickness of the coating (the stiffness is proportional to the cube of the thickness), so if other factors remain constant, the coating with a lower weight generally provides greater flexibility and thus the coating can be embossed.

Process of Post-Embossing Textured Films

In an alternative embodiment shown in Figure 3, once post-embossing is performed on the stencil, an intermediate or finished product (rather than a release stencil) will be made. Referring to Figure 3, in process 200, a first texture (e.g., a micron or nanoscale texture) is applied to a plastic template or to a plastic coating of a paper template using a first replication surface (step 210). The first texture can be applied using any desired technique, such as with a release template carrying the first texture as the first replicated surface, or utilizing any of the techniques described above, and the like.

The desired texture is then embossed on the textured template, for example using an engraving roll, to provide a second replicated surface (step 220).

The plastic film or coating can be formed, for example, by extrusion or other techniques used to form the sheet-like plastic substrate. In some cases, the template comprises a polypropylene sheet. In other cases, the template comprises a paper template, for example by extruding polypropylene onto a chill roll textured with a micron or nanoscale texture while holding the paper template to deposit polypropylene on the paper form. coating. As another example, a polypropylene film can be extruded or laminated to a paper form and then a micro or nano-scale texture applied to the polypropylene surface.

Thermoplastics other than polypropylene, such as vinyl, polymethyl methacrylate, and other thermoplastics used in the imprint process, can be used.

The embossing temperatures for the initial and post embossing will be selected depending on the softening temperature and melting temperature of the particular thermoplastic used. The stencil temperature during post embossing should generally be low enough so that the micron or nanoscale pattern is not adversely affected and the coating does not melt. This temperature will depend on the melting temperature of the thermoplastic used. For polypropylene, the preferred temperature for subsequent imprinting is typically a temperature above the softening temperature of the polypropylene but less than 200 °F.

The embossing pressure is usually the same as the pressure discussed above in the Process Parameters section.

In some cases, the polypropylene and/or paper may be pre-printed with a desired pattern, for example, the paper may be a decorative paper.

The post-imprint template can be a finished product, or it can be an intermediate product, for example, the post-imprint template can be subjected to further processing steps such as adhering to the substrate and/or cutting it into a sheet.

Example 1

The release template shown in Figure 4 is manufactured using the following process:

A 158 g/m2 fiber base paper was coated with a clay coating that provided acrylic coating retention and adhesion. An acrylic coating (the composition of which is shown in Table 1 below) was applied to the substrate using an offset gravure coating assembly at a coating speed of 18 g / m ² , 60 ft / min. The coated paper was then wrapped around the nickel sleeve with a micro-scale Sharklet pattern and cured using an electron beam at a dose of 4 Mrads. The microscale Sharklet pattern has a 2 micron feature spacing, a 10 micron width feature, and a 2.1 micron feature depth.

A cured paper having a micron-scale texture is wound into a finished roll.

The paper is embossed in a separate process step as follows:

The stencil is controlled by a tension roller and between the embossing roller and the elastic back roller. The engraved impression roller was preheated to 220 °F and the nip was closed and loaded to a pressure of 1800 RPI. The paper was run at a speed of 60 feet per minute to impart a macro-scale texture of the embossing roll to the paper substrate and to wind the micro/macro-scale textured paper release stencil (as shown in Figure 4) into a roll.

form 1

Example 2

The texture of the polyurethane coated fabric shown in Figure 4A was prepared using the following method:

A polyurethane surface coating having a thickness of about 75 μm was cast onto the release paper formed in Example 1 shown in Fig. 4, and heated to 140 ° C for 2 minutes to remove the solvent. The coating composition included 80% by weight of Stahl Holdings' SU 10-104 (product name) polyurethane resin, 8% DMF (dimethylformamide), and 15% Stahl VP-048-031 pigment.

A urethane adhesive coating (120 microns thick) was cast onto the pre-cured cast polyurethane skin coating. The coating composition was 80% by weight of IMAPUR 5105 polyurethane resin, 8% DMF (dimethylformamide) and 15% Stahl VP-048-031 dispersant.

The non-woven fabric was then sandwiched into a wet polyurethane adhesive coating, heated to 140 ° C for two minutes and allowed to cool.

The resulting fabric/urethane composite had a micro/macro surface texture of the replicated release paper and was peeled from the release paper as shown in Figure 4A.

Other embodiments

A number of embodiments have been described. However, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure.

For example, there are many other examples of coatings that can be used in the processes discussed herein. In addition to the above-described examples of known free-radically curable acrylates, other radiation (UV or electron beam) coatings are also useful. Examples of radiation-cured coatings are generally divided into three main groups: "radical polymerization", "ion polymerization" and "body-receptor polymerization".

As described above, a typical resin which is cured by radiation-induced radical polymerization: a (meth) acrylate resin is sold by Arkema (Sartomer) Inc.; a radical-initiated step-growth polymerization can also be carried out by using a thiol- Unsaturated polyester: NOVOC® Performance Resins, supplied by Andara Inc.; with a mercaptan such as trimethylolpropane tris(3-mercaptopropionate) as a curing agent: THIOCURE® TMPMP, supplied from Evans Chemetics ( Bruno Bock).

The free radical polymerization can be charge transfer or donor-acceptor polymerization with a donor such as a vinyl ether and a acceptor such as a maleate functional resin. Examples of this type of formulation include: from BASF vinyl ether, triethylene glycol divinyl ether DVE-3 as a donor; unsaturated maleate capping resin from Piedmont Chemical as a acceptor.

Ionic polymerization generally follows radiation-induced anion or cationic catalysis. Typical resins which are cured by base-catalyzed radiation-induced ionic polymerization are thiol-thiol or Michael additions of thiols and acrylates, but many other base catalyzed polymerization systems are known. Photobase generators such as CGI-90 from BASF produce a strong base upon absorption of radiation which induces the use of mercaptans for anionic curing towards Michael reaction or direct anionic curing. A well-known example of acid catalyzed ionic polymerization is cationic polymerization of an alicyclic epoxy resin such as Dow's CYRACURETM UVR-6110 with an acid catalyst such as BASF's IRGACURE® 250. Glycidyl based epoxy resins, such as EPOTUF® 31-127, can also be polymerized by acid catalysis under UV or electron beam radiation with a suitably selected catalyst. In each case, appropriate screening of the catalyst and radiation source should be performed to form free radicals or acids/bases to induce polymerization.

For each of the above general examples, various combinations and/or "hybrids" can be made to adjust the reaction rate and final mechanical properties. The above coating systems can generally be thermally polymerized with a suitable catalyst, although typically slower than UV or electron beam curable resins. It will be understood by those of ordinary skill in the art that various ratios of oligomers, diluents, additives (e.g., wetting agents, catalysts, photoinitiators, such as fillers, etc.) can be adjusted to suit the particular application desired for the coating. Curing rate and mechanical properties.

The release template discussed herein can be used to cast textured silicone sheets or stencils. The textured naphthenic sheets can then be joined together to form a mold that can be used to create a nickel sleeve. The resulting nickel sleeve can be used as a replication surface as a further release template, for example, by embossing a polypropylene coated paper template to carry the micron or nanoscale and macroscale texture of the original release template.

In summary, other embodiments are also included in the scope of the patent application of the present invention.

10‧‧‧away template

12‧‧‧Substrate

14‧‧‧ Coating

16‧‧‧micron scale

18‧‧‧ macro scale

100, 200‧‧‧ Process

139‧‧‧ template

110, 120, 130, 140, 210, 220‧ ‧ steps

141‧‧‧ nip

142‧‧‧ Engraving roller

143‧‧‧Flexible back roll

1 is a partial schematic side cross-sectional view of a release liner in accordance with one embodiment.

1A is a partial schematic side cross-sectional view of a release liner in accordance with an alternative embodiment.

2 is a flow chart showing a process for fabricating a release template in accordance with one embodiment.

Fig. 2A is a schematic view showing the process of Fig. 2.

3 is a flow chart showing a process for fabricating a post imprint template in accordance with one embodiment.

Figures 4 and 4A are photomicrographs of release paper taken using a confocal microscope and polyurethane fabric made using release paper, respectively. Release papers and fabrics include a macroscopic scale pattern of leather superimposed on a Sharklet micron-scale pattern.

Claims (27)

A release casting template for a replica cast of a curable system, the release liner comprising: a substrate; and a coating disposed on at least one surface of the substrate, the coating having a casting A surface effect that is replicated during the surface, wherein the surface effect comprises a first three-dimensional texture on a micro or nano scale, and a second three-dimensional texture on a macro scale. The release template of claim 1, wherein the second three-dimensional texture is post-embossed on the first three-dimensional texture during manufacture of the release template. The release template of claim 1, wherein the first three-dimensional texture is selected from the group consisting of a diffraction grating, a hydrophobic surface texture, a laser interference rainbow pattern, and combinations thereof. The release template of claim 1, wherein the first three-dimensional texture is selected from the group consisting of a lenticular texture, a drag reduction texture, a cube corner texture, and combinations thereof. The release template of claim 1, wherein the second three-dimensional texture has a characteristic depth of about 50 to 300 microns. The release liner of claim 1, wherein the first three-dimensional texture has a characteristic length of from about 1 to 100 microns and a feature width of from about 1 to 10 microns. The release template of claim 1, wherein the first three-dimensional texture has a feature pitch of about 1 to 10 microns, and a feature depth or height of about 1 to 10 microns. The release liner of claim 1, wherein the coating comprises an acrylate. The release liner of claim 1, wherein the coating comprises polypropylene. The release liner of claim 1, wherein the flexible substrate comprises paper or plastic. A method comprising: applying a coating to a flexible substrate; and placing a first three-dimensional texture on a micro or nano scale and a second three-dimensional texture on a macro scale on the coating to form A release template with a textured surface. The method of claim 11, further comprising curing the coating after setting the first three-dimensional texture and before setting the second three-dimensional texture. The method of claim 12, wherein the providing the second three-dimensional texture comprises imprinting the cured coating. The method of claim 11, wherein at least one of the textures is formed by pressing the coating against a surface of an engraving roll. The method of claim 13, wherein the imprinting is performed by pressing the cured coating against a heated replication surface. The method of claim 15, wherein the replication surface is heated to a temperature greater than a glass transition temperature of the cured coating. The method of claim 15 wherein a pressure of at least 1000 PLI is applied at the nip. The method of claim 11, wherein the first three-dimensional texture is selected from the group consisting of a diffraction grating, a hydrophobic surface texture, a laser interference rainbow pattern, and combinations thereof. The method of claim 11, wherein the first three-dimensional texture is selected from the group consisting of a lenticular texture, a drag reducing texture, a cube corner texture, and combinations thereof. An article of manufacture comprising: a flexible template having a textured surface comprising micron, nanoscale, macroscale features disposed on the same region as the flexible template. The article of claim 20, wherein the flexible template comprises a textured polymer layer. The article of claim 21, wherein the flexible template further comprises a sheet of material laminated to the textured polymer layer. The article of claim 22, wherein the sheet material is selected from the group consisting of fabric, board, paper, and foil. The article of claim 20, wherein the first three-dimensional texture of the nanometer scale is selected from the group consisting of a diffraction grating, a hydrophobic surface texture, a laser interference rainbow pattern, and combinations thereof. The article of claim 20, wherein the first three-dimensional texture on a micrometer scale is selected from the group consisting of a lenticular texture, a drag reduction texture, a solid angle texture, and combinations thereof. A method of making an article having a textured surface, the method comprising: mechanically imprinting a macro-scale three-dimensional texture on a template having a surface having a micro- or nano-scale three-dimensional texture. A method comprising: casting a resin onto a textured release template to form a textured ruthenium replica template having a macroscale texture and a micro or nanoscale texture disposed on the release template Forming a mold comprising the textured ruthenium replica template; using the mold to produce a nickel sleeve; and utilizing the nickel sleeve as a replication surface to impart a macroscale, micron or nanoscale texture to a second Release template.