Pigment transfer material for transferring images onto textile substrates

Abstract

The present invention relates to pigment transfer materials. Specifically, the present invention relates to pigment transfer materials for transferring images onto a textile substrate. The present invention further relates to a method for transferring an image from a pigment transfer material to a textile. The pigment transfer material includes a base layer and a transfer coating.

Description

[Technical Field]

[0001] This invention relates to pigment transfer materials. Specifically, it relates to pigment transfer materials for transferring images onto a textile substrate. Furthermore, it relates to a method for transferring an image from a pigment transfer material to a textile. [Background technology]

[0002] Pigment transfer materials, such as pigment transfer sheets or pigment transfer paper, are known in the art for providing images on a woven fabric substrate.

[0003] An example is provided in WO00 / 06392, which describes a transfer paper suitable for inkjet printing. The transfer paper includes a release layer or a barrier layer. The transfer paper can provide an image using sublimation dyes. The method of providing the transfer paper and image onto the fabric allows for flexibility. However, this application is generally limited to synthetic fibers due to the inadequate binding of sublimation dyes to natural fibers.

[0004] An example of a method for providing images on natural fibers is proposed in WO2020 / 256549. This pigment transfer sheet has a transfer layer and an optional release layer. An image can be printed on the transfer layer. The image can be transferred to the fabric by placing the transfer layer on the fabric and applying heat and pressure. The release layer is used to ensure that at least a portion of the transfer layer is transferred to the fabric along with the image.

[0005] WO2005 / 077663 describes an image transfer material comprising a support, a molten transfer layer, and an image receiving layer. Printing on the receiving fabric can be performed by inkjet printing an image onto a sheet. Subsequently, the molten transfer layer and the image receiving layer are peeled off from the support layer. The molten transfer layer and the image receiving layer are placed on the receiving fabric, and heat is applied to melt the transfer layer and adhere the image to the fabric. Disadvantageously, it requires separating the support layer from the molten layer and the image receiving layer before application. This reduces the scalability of this method. Furthermore, it is not possible to print large surfaces of fabric using this image transfer material. Additionally, because a plastic layer remains on the fabric, the "feel" of the fabric deteriorates and the colorfastness to washing is reduced.

[0006] US5981077 describes an image transfer sheet as comprising a substrate, a release layer, and an image transfer layer. The image transfer layer contains a self-crosslinking polymer. A drawback of the transfer sheet is that removal of the transfer sheet after printing requires low temperatures, which limits its large-scale applicability.

[0007] Further examples are provided in US4351871, which describes a decorative material having a flexible substrate and a transferable layer having a maximum thickness of 20 microns. The transferable layer is provided with an image, which is transferred to the receiving fabric by applying heat and pressure. However, the applicability is limited because the printing of the image is carried out by gravure printing, and this method requires special inks specially prepared for the process. [Overview of the project]

[0008] The inventors have, surprisingly, found a pigment transfer material and an improved process that addresses at least some of the aforementioned drawbacks. In particular, the inventors have, surprisingly, found a pigment transfer material that requires only a single coating to address at least some of the aforementioned drawbacks. [Brief explanation of the drawing]

[0009] [Figure 1A] Provide a schematic view of the pigment transfer material according to the present invention. [Figure 1B] Schematically show the pigment transfer material according to the present invention on which an image is printed. [Figure 2] Schematically show a process for transferring an image from a pigment transfer material to a fabric substrate according to the present invention. [Figure 3] Schematically show a preferred embodiment of the process according to the present invention. [Figure 4] Schematically show another preferred embodiment of the process according to the present invention.

[0010] Therefore, the present invention is directed to a pigment transfer material (also referred to herein as "transfer material" and "material") suitable for transferring an image to a fabric substrate. As shown in FIG. 1A, the transfer material (1) includes a base layer (11) and a transfer coating (12). "Transfer coating" and "coating" are used synonymously herein.

[0011] The inventors have further surprisingly found that the method by which an image is transferred to a fabric substrate (also referred to herein as "fabric" and "substrate") can affect the transferability of the image and the transfer coating to the fabric. Therefore, another aspect of the present invention relates to a method of transferring an image from a pigment transfer material to a fabric substrate.

[0012] The transfer coating has multiple functions. First, the transfer coating has the function of receiving an image, for example, by printing. Second, the transfer coating has the function of facilitating the transfer of the image onto the fabric substrate. Third, the transfer coating enables the peeling of the base layer. To perform these functions, the transfer coating has a thickness in the range of 10 - 50 μm, preferably in the range of 25 - 40 μm, for example, in the range of 30 - 35 μm, and / or a melting temperature in the range of 140 - 210 °C, preferably in the range of 150 - 190 °C, more preferably in the range of 160 - 180 °C.

[0013] The melting temperature in this specification is used to describe the temperature at which at least a part of the coating begins to melt. The melting temperature can be determined by any suitable means in the art, for example, by providing a transfer coating on a substrate that can withstand a high temperature of 220 °C or higher, and determining the temperature at which the coating disposed thereon begins to melt. A specific example thereof is to provide a transfer coating on a metal plate, dry the transfer coating, and then transfer the coating to a cotton pad and place this in an oven. Then, the oven is heated step by step, for example, in steps of 10 °C or 15 °C, from 105 °C to 220 °C, until the coating melts and adheres to the cotton pad.

[0014] The melting temperature of the transfer coating is particularly suitable for the transfer step (see below), and it has been found that it enables easier peeling after the transfer step.

[0015] The thickness of the transfer coating may be determined by any suitable means in the art. As an example, it is to measure the thickness of the base layer before applying the transfer coating and measure the thickness of the pigment transfer material (with the measured base layer). Then, subtract the thickness of the base layer from the thickness of the pigment transfer material to obtain the thickness of the transfer coating.

[0016] It has been found that a part of the transfer coating is transferred to the fabric together with the image. For example, 5 to 95% by weight, preferably 40 to 90% by weight, for example about 85% by weight of the total weight of the transfer coating can be transferred to the fabric together with the image. It can be understood that this total weight of the transfer coating is based on the dry weight of the coating. Because the thickness of the transfer coating is within a specific range, the transfer of a part of the coating results in a thin layer on the fabric. This not only makes it possible to essentially maintain the original texture and fabric properties of the fabric substrate, but also enables good durability of the image transferred onto the fabric.

[0017] Analytical methods for determining the feel of a fabric exist in the art. One such method is the Kawabata Evaluation System (KES, see also Harwood et al. Journal of the Society of Dyers and Colourists 106(2008) 64-68). Alternatively, feel can be tested using a fabric touch tester (FTT® M293), described in US6601457, commercially available from SDL Atlas LLC, USA, and performed as described in Binti Haji Musa et al. (2018) Practical Considerations of the FTT Device for Fabric Comfort Evaluation Journal of Fashion Technology & Textile Engineering S4:003 (hereinafter referred to as "determined by FTT"). The aforementioned literature by Binti Haji Musa et al. (2018) is incorporated herein by reference in its entirety. Feel can also be determined by the touch perception of a test panel of one or more experts.

[0018] Generally, good transfer properties indicate that the transfer coating has a density of at least 15 g / m² based on the dry weight of the coating. 2 This is obtained when present in the transfer material in an amount of . Better results were obtained for larger transfer coatings, therefore preferably at least 25 g / m² 2 It is present, and more preferably at least 30 g / m² 2 Such coatings exist. Typically, the coating is 60 g / m². 2 Less than, for example, 50 g / m² 2 Less than 40g / m² 2 It exists at a level less than 30 g / m². The transfer coating is approximately 30 g / m². 2 The best results were obtained when it was present in that quantity.

[0019] Typically, to obtain the desired dry weight as detailed above, use 50-90 g / m². 2, for example, apply the total amount of the coating of 60 to 80 g / m 2 in its wet state. The transfer coating may be applied in a single coating step. Therefore, the production of the pigment transfer material according to the present invention is relatively easy. However, it can be understood that the coating may also be applied in a plurality of separate steps. This can be beneficial for systems that do not allow the application of the total amount of the coating in a single step. Typically, the materials used (i.e., the composition of the transfer coating) are essentially the same in each of the coating steps (e.g., more than 95% identity, such as more than 98%) to provide the transfer coating. The method by which the coating is applied is not particularly limited. The coating can be applied using a conventional coating method such as roll coating, for example.

[0020] It can be understood that the pigment transfer material can consist of a base layer and a transfer coating. Therefore, no additional layer is required between the base layer and the transfer coating and / or on top of the transfer coating. In particular, the transfer coating may be a single coating layer. The single coating layer of the transfer coating can be obtained by a single coating step. However, the single coating layer of the transfer coating can also be obtained by a plurality of coating steps. As long as the materials used (i.e., the composition of the transfer coating) are essentially the same in each step, it is considered a single coating layer for the purposes of the present invention.

[0021] The transfer coating can be partially transferred to the fabric and may allow for easier peeling after the transfer step. The inventors have found that this can be achieved by providing a polyolefin in the transfer coating. The presence of a polyolefin in the transfer coating is preferable when the pigment transfer material comprises the transfer coating as a single coating layer and the pigment transfer material does not contain a release layer. The polyolefin typically melts at a temperature suitable for the transfer step (see below) and thus can allow for the release of a portion of the transfer coating. Furthermore, the melting properties of the polyolefin typically allow the transfer material to be used as a so-called hot-peel material, which means that after the transfer step, the base layer can be separated from the fabric product at a high temperature (see below).

[0022] Therefore, the transfer coating preferably contains a polyolefin. Typical examples of polyolefins include polyethylene (PE), polypropylene, and polybutylene. In this invention, the polyolefin preferably contains polyethylene. Polyethylene can be classified based on its molecular weight and branching. Types of polyethylene include low-density polyethylene (LDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), and ultra-high molecular weight polyethylene (UHMWPE). Preferably, the transfer coating contains low-density polyethylene (LDPE) and / or high-density polyethylene (HDPE). The best results were obtained with HDPE. Therefore, HDPE is most preferred.

[0023] The transfer coating may further contain one or more components, among other things, to enable better printability, drying ability, and shelf life. Printability is used herein to indicate the adhesion of the image pigment, ink, or dye to the transfer coating. Drying ability is used to describe how quickly the image pigment, ink, or dye dries after being applied to the transfer coating. Further components include one or more of a softener, silica, binder, wetting agent, thickener, and / or defoamer. Typically, the transfer coating is based on an aqueous solution containing one or more components and / or a polyolefin. More preferably, the transfer coating is based on an aqueous solution containing a polyolefin, a softener, silica, a binder, a wetting agent, and a thickener. Therefore, the transfer coating preferably contains one or more components and / or a polyolefin. More preferably, the transfer coating contains a polyolefin, a softener, silica, a binder, a wetting agent, and a thickener.

[0024] Fabric softeners can contribute to improved tactile feel. For example, the drape of the fabric may be improved. In addition, fabric softeners can enable improved printability, such as a reduced tendency for ink to bleed. A further advantage of using fabric softeners is that they allow for improved transfer of the coating to the fabric. For example, the pressure required for transfer may be reduced. It has also been found that fabric softeners reduce the peeling force required to remove the transfer material from the fabric substrate after transfer. The use of fabric softeners can also lead to improved friction fastness of the print.

[0025] Suitable softeners may be silicone-based, such as polysiloxanes, fatty acids, fatty amides, and / or paraffins. It may be preferable to use silicone-based softeners. Silicone-based softeners can be advantageously used to allow the printed fabric to retain a feel close to the original fabric. Silicone-based softeners are known in the art (see, for example, Islam M et al. American Journal of Polymer Science & Engineering 2014, 3:129-138). Silicone-based softeners may be based, among others, on polydimethylsiloxane, amide-functional silicone, amino-functional silicone, methyl hydrogen silicone, epoxy-functional silicone, hydroxy-functional silicone, silicone polyether and epoxy polyether silicone, and any combination thereof.

[0026] The presence of a softener in the transfer coating can affect the surface properties of the pigment transfer material. While the presence of a softener is desirable for an improved feel, it should not be detrimental to the printability of the pigment transfer material. For good printability, the total free surface energy of the pigment transfer material, as measured on the transfer coating surface, is preferably 50-100 mN / m, more preferably 60-90 mN / m, and even more preferably 70-80 mN / m, determined using CH2I2 and water according to ISO 19403-2:2017. If the total free surface energy is too low, the ink may not wet properly, while if the total free surface energy is too high, the clarity of the print may be reduced. In particular, by using a softener according to the present invention, specifically a silicone-based softener, the total free surface energy of the pigment transfer material can be maintained within these ranges.

[0027] In addition, for good printability, the gloss level of the pigment transfer material, as determined on the transfer coating surface at an 85° angle according to DIN EN ISO2813-2015-02, was found to be preferably less than 3 GU, more preferably 1.2 to 2.5 GU, even more preferably 1.4 to 2.0 GU, and most preferably 1.4 to 1.9 GU. Also preferably, the smoothness of the pigment transfer material, as determined on the transfer coating surface using a Gurley tester (standard pressure) according to ISO5636 / 5, was preferably more than 400 seconds, more preferably 450 to 900 seconds, and even more preferably 500 to 720 seconds.

[0028] Silica (silicon dioxide, SiO2) can be used to reduce blocking. Blocking is a term known in the art to describe the tackiness of a coating. Silica can also be used to extend the shelf life of transfer materials.

[0029] The addition of an optional binder allows for good bonding of the transfer material to the fabric, as well as good bonding of the transfer coating to the base layer. Additionally, the binder may enable improved colorfastness to washing of the image on the fabric. Colorfastness to washing is, in particular, a measure of the color properties and can be determined by ISO Test Method 105A2:1993. A further advantage of using a binder is that it enables better printability and faster drying. Suitable binders may include polyurethanes such as cationic polyurethane, polyacrylate, carboxymethylcellulose, hydroxyethylcellulose, polyvinyl acetate, and / or poly(vinyl alcohol). In particularly advantageous embodiments, at least two binders are used. Therefore, the combination of polyurethane and poly(vinyl alcohol) is most preferred. This is particularly beneficial because, for example, polyvinyl alcohol can provide printability and drying properties, while polyurethane can provide colorfastness to washing.

[0030] Wetting agents can be used to disperse polyolefins in an aqueous environment. Wetting agents may also be called surfactants. Typically, surfactants are amphiphilic, i.e., compounds having both a hydrophobic tail and a hydrophilic head. Suitable surfactants are known in the art and may include nonionic wetting agents. Examples of suitable surfactants include ethoxylates and their copolymers, and acrylamide polyglycols.

[0031] Thickeners are typically applied to increase the viscosity of the aqueous solution on which the transfer coating is based. Higher viscosity can be beneficial for applying the transfer coating to the base layer. Suitable thickeners include carboxymethylcellulose, polyurethane, polyacrylate, and / or starch.

[0032] Defoaming agents (also called foam inhibitors) are typically used to remove excess foam during coating preparation. Defoaming agents are known in the art, and preferred examples include soap, mineral oil, fatty alcohol, and / or paraffin wax.

[0033] The following transfer coatings yielded good results: -50 to 100 parts by weight of polyolefin, -80 to 130 parts by weight of binder, -20 to 50 parts by weight of softener, -2 to 20 parts by weight of silica, -Optionally, one or more of the following: thickeners, defoamers, and wetting agents.

[0034] The amounts of binder, softener, and silica are each individually (based on dry weight) per 100 parts by weight of polyolefin. Thickeners, defoamers, and wetting agents are typically present in a total amount of 60 to 80 parts by weight (i.e., the sum of the amounts of thickener, defoamer, and wetting agent) per 100 parts by weight of polyolefin. For example, per 100 parts by weight of polyolefin, the thickener may be present in an amount of 1 to 8 parts by weight, the defoamer in an amount of 1 to 8 parts by weight, and / or the wetting agent in an amount of 50 to 70 parts by weight.

[0035] Better results were obtained with transfer coatings that included the following: -80 to 100 parts by weight of polyolefin, -100 to 120 parts by weight of binder, -25 to 35 parts by weight of softener, -10 to 20 parts by weight of silica, -Optionally, one or more of the following: thickeners, defoamers, and wetting agents.

[0036] The amounts of the binder, softener, and silica are each individually (based on dry weight) per 100 parts by weight of polyolefin. The thickener, defoamer, and wetting agent are preferably present in a total amount of 65 to 75 parts by weight per 100 parts by weight of polyolefin. For example, per 100 parts by weight of polyolefin, the thickener may be present in an amount of 2 to 6 parts by weight, the defoamer in an amount of 2 to 6 parts by weight, and / or the wetting agent in an amount of 55 to 65 parts by weight.

[0037] Therefore, the present invention further relates to aqueous compositions for providing a transfer coating on a base layer to obtain pigment transfer paper. Accordingly, this aqueous coating comprises water and the components described above for the transfer coating, preferably in the same amounts as those detailed above for the coating.

[0038] Preferably, the transfer material, in particular the transfer coating, allows for rapid drying of the image provided on the coating. The pigment transfer material may have the image provided on the transfer coating, for example, by printing. This is illustrated in Figure 1B, where a pigment transfer material (1) comprising a base layer (11) and a transfer coating (12) has an image (13). Typically, the image is touch-dried before the printed roll is wound. In other words, the drying capacity of the pigment transfer material is typically sufficient to achieve continuous printing onto the pigment transfer material without ink cancellation while the printed pigment transfer material is being wound.

[0039] Whether the image is touch-dry and the corresponding drying ability of the pigment transfer material can be determined by the following method. Prints images in black (K) with -10, 20, 30, 40, 50, 60, 70, 80, 90, and 100% ink coverage. This corresponds to 0.36, 0.80, 1.42, 2.14, 2.94, 4.08, 5.23, 6.67, 8.57, and 11.54 ml / m². 2 This corresponds to the ink (i.e., ink level). The ink used is Kiian's Digistar K-Choice 4.0. - Start the timer immediately after printing is complete. -After 5 minutes, at least the printed pigment transfer material test image was 80g / m². 2 Canon Orange Label Performance A4 80g / m² copier paper 2 Cover with white. - A 10kg roller is rolled three times over the copier paper covering the test image, pressing the copier paper onto the printed pigment transfer material. Note that the roller should be large enough to cover the entire surface area of ​​the printed test image. - Separate the copier paper from the printed pigment transfer material. - For example, visually check whether the ink has been transferred from the printed pigment transfer material to the copier paper. - The ink level without ink offset is the drying capacity of the pigment transfer material. The drying capacity is ml / m after 5 minutes of drying. 2 It will be recorded.

[0040] Preferably, the drying capacity of the pigment transfer material is 0.5 ml / m² after drying for 5 minutes. 2 ~8ml / m 2 That is the case.

[0041] The base layer is typically a base paper layer. Preferably, the base layer is cellulose-based. The open structure of the base layer, such as paper, positively contributes to the drying time of the printed image, which is particularly important for water-based inks. For this reason, a base paper layer is preferred over a polymer film layer. A typical base paper is 60 g / m². 2 ~100g / m 2 The paper has a basis weight of 70 g / m², more preferably 70 g / m². 2 ~90g / m 2 The base paper has a basis weight of 80 g / m², most preferably 80 g / m². 2 ~90g / m 2 This is a base paper with a basis weight of approximately 85 g / m². 2 This base paper is used because it allows for a sufficiently strong paper.

[0042] The base paper may contain soft and / or hard wood fibers, and additionally one or more fillers, sizing agents, wet strength and dry strength agents, yield enhancers, and starch.

[0043] The base layer, particularly the base paper, can also be characterized by its Cobb value. This value provides information about its water absorption capacity. The Cobb value can be determined by a test that measures the amount of water absorbed by a defined area of ​​the paper through one-sided contact with water over a certain period of time. The Cobb value can be determined according to ISO 535, such as ISO 535:2014 or ISO 535:2023. Preferably, the base layer has a Cobb value of 15-50 g / m². 2 Cobb value, more preferably 20-40 g / m² 2 For example, about 25g / m2 It has a Cobb value of .

[0044] Another characteristic of the base layer is its porosity. The porosity is preferably up to 300 ml / min, preferably up to 280 ml / min, and more preferably up to 250 ml / min. Porosity is expressed herein as benthocene porosity and is determined by ISO 5636-3. Typically, pigment transfer materials have low porosity (e.g., up to 5 ml / min, or even 0 ml / min).

[0045] Transfer materials can be used to provide an image to a woven fabric substrate. The fabric may be synthetic or based on natural fibers or blends thereof. Examples of natural fibers on which the fabric may be at least partially based include cotton, viscose, silk, coir, flax, hemp, jute, ramie, sisal, mohair, cashmere, camel hair, and wool, or combinations thereof. Synthetic fabrics may be, for example, nylon-based, spandex, and / or elastane-based fabrics. Preferably, the fabric is cotton or viscose-based, more preferably cotton-based.

[0046] Figure 2 shows a method for achieving the transfer of an image from a transfer material to a fabric. This method includes providing a pigment transfer material (1) comprising a base layer (11) and a transfer coating (12), wherein a pigment image (13) is provided (e.g., printed) on the transfer coating. The pigment transfer material is preferably as detailed above. This is followed by a superposition step, which includes superimposing the pigment transfer material and the fabric substrate by bringing the transfer coating into contact with the fabric substrate (2). This method further includes a transfer step, which includes applying pressure and heat to the superimposed and contacted transfer material and fabric substrate. In this transfer step, the heat is provided from a heat source facing the transfer coating. This step is followed by a peeling step, which includes separating the base layer from at least a portion of the fabric substrate and the transfer coating. As detailed above, at least a portion of the transfer coating, such as the upper layer (12b), is transferred along with the image, and at least a portion of the transfer coating, such as the lower layer (12a), remains on the base layer.

[0047] It has been found that supplying heat from a heat source facing the transfer coating allows for more complete transfer. Although we do not wish to be constrained by theory, it is thought that a small temperature gradient is formed within the transfer coating. The temperature of the portion of the transfer coating closest to the heat source may be slightly higher than that of the portion further away. Therefore, the portion closest to the heat source may be slightly more melted, thereby potentially making the transfer to the fabric substrate easier. The temperature gradient may allow the bottom layer of the transfer coating to remain attached to the base layer while the top layer of the transfer coating is released.

[0048] The heat applied during the transfer step is typically such that the overlapping, contacted transfer materials and textile substrates are heated to a temperature in the range of 100–250°C. Some textile substrates may not be sufficiently heat-resistant to temperatures above 220°C or 210°C. For example, pure cotton may yellow slightly at such temperatures. Therefore, a temperature in the range of 150–210°C may be preferable. Transfer coatings allow for good results at temperatures in the range of 160–200°C. The most preferred range is 180–190°C. Textile substrates are typically sufficiently resistant to these temperatures, and the transfer coatings are sufficiently meltable at these temperatures to allow for image transfer, and temperatures are typically easily achieved in industrial environments.

[0049] The pressure applied during the transfer step may be a surface pressure, for example, a pressure of at least 0.40 bar or at least 0.50 bar. Surface pressure, as used herein, means the amount of pressure applied to the surfaces of the superimposed pigment transfer material and fibrous substrate. In the art, this is often referred to as set pressure (i.e., the pressure setting indicated by the pressure-providing device). However, it can be understood that set pressure is not always equal to surface pressure and typically requires conversion.

[0050] Pressure can be delivered using various means. One example is a hot press. As detailed above, the pressure set on a hot press may not be equal to the surface pressure actually applied to the superimposed transfer material and fabric substrate. For example, depending on the hot press, the pressure may be set in the range of 1 to 100 bar, but this pressure is generally related to the pressure applied to the cylinder driving the pressure plate. Since these pressure plates have a much larger surface area than the cross-section of the cylinder, the set pressure is not equal to the surface pressure (i.e., the pressure applied to the superimposed material and substrate by the pressure plate). Therefore, the set pressure can be converted to surface pressure using their respective surface areas. Surface pressure can also be determined by using analytical techniques such as pressure paper or pressure sensors.

[0051] A particular advantage of the pigment transfer material and process according to the present invention is that the transfer step (i.e., applying pressure and heat to the superimposed, contacted transfer material and textile substrate) can be performed using calendering. Calendering conditions that yield superior transfer results in terms of degree and quality are similar to those of WO2020 / 256549, which is incorporated herein by reference. Calendering allows for continuous processing, processing of textile substrates with large surface areas, and good control over process parameters. Thus, calendering is ideally suited for large-scale processes.

[0052] In the calendering process of this invention, any type of calender can be used as long as it can provide the desired transfer step conditions (e.g., sufficient temperature, pressure, and residence time). Preferred calenders are, for example, lamination calenders and conventional transfer calenders. Conventional transfer calenders have traditionally been used for sublimation transfer, while lamination calenders (also referred to as coating calenders or laminate and coating calenders) have traditionally been used to laminate or coat woven fabrics such as nonwovens. Such calenders are commercially available, for example, from Klieverik Heli BV in the Netherlands and Monti Antonio SpA in Italy. In this invention, lamination calenders are particularly preferred because, by equipping the calender with a lamination cylinder, sufficient pressure to obtain good transfer results can be easily provided. However, conventional transfer calenders adjusted to provide sufficient pressure are also very preferred because this relaxes the requirement to provide two types of calenders for sublimation transfer and transfer according to this invention.

[0053] When calendering is used in the process according to the present invention, the pressure applied during the transfer step may be represented by the set pressure (see below), which is the pressure indicated by the calendering apparatus. However, the set pressure is not typically directly equal to the amount of pressure actually applied to the transfer material and the woven substrate (referred to herein as surface pressure). In the art, the calender pressure during sublimation transfer is typically set, for example, in the range of 2 to 10 bar, but the pressure directly applied to the transfer material and the woven substrate depends, among other things, on the size of the cylinder used and is therefore not generally equal to the set pressure, but generally much lower. However, by taking into account the contact surface area, the set pressure can be converted to surface pressure. In addition to affecting the set pressure, the surface pressure during the transfer step can also be increased by providing a web sheet that is fed through the calender together with the overlapping pigment transfer material and the woven substrate. The web sheet has a thickness that results in increased pressure on the overlapping pigment transfer material and the woven substrate, resulting in improved results in terms of the degree and quality of transfer.

[0054] Surface pressure can play a role in the transfer result, but better results can be obtained with a pressure impulse. Such a pressure impulse, for example, a surface pressure impulse, can be provided by a lamination cylinder. In particular, good transfer results can be obtained if the transfer step includes a pressure impulse introduced at the start of the transfer step. A pressure impulse means a temporary increase in pressure compared to the surface pressure provided during at least part of the transfer step in the residence time window (i.e., the time during which the overlapping contacted transfer material and the fabric substrate are heated and pressed to achieve a sufficient transfer). Preferably, the pressure impulse is provided in the first half of the residence time, more preferably within the first quarter of the residence time. The pressure impulse may be provided by a calendar adapted to provide the pressure impulse, for example, by the lamination cylinder described above. In addition to or alternative to the pressure impulse provided by the lamination cylinder, the pressure impulse may also be provided by a feed cylinder, which may be referred to in the art as a feed roller.

[0055] In a preferred embodiment, the surface pressure impulse is at least 0.02 N / mm 2 The pressure, preferably at least 0.03 N / mm² 2 Preferably at least 0.05 N / mm 2 For example, at least 0.06 N / mm 2This is a surface pressure impulse. Note that this surface pressure is the actual pressure applied to the surface of the superimposed transfer material and woven substrate, not the set pressure. This surface pressure impulse typically corresponds to a set pressure impulse of at least 2 bar, such as at least 4 bar or at least 6 bar. It has been found that pressure impulses of these values ​​can compensate for lower surface pressures applied during the remaining time (i.e., residence time) when heat and pressure are applied. In embodiments where a pressure impulse is applied, it has been found that the complementary surface pressure applied during the residence time can be even lower than 0.40 bar. Therefore, conventional calendars, such as ordinary transfer calendars that cannot provide a constant surface pressure of 0.40 bar or more, can nevertheless be used by equipping them with a cylinder adapted to provide a pressure impulse.

[0056] Figures 3 and 4 illustrate specific embodiments of the present invention, including calendering with pressure impulses. The arriving pigment transfer material (1) and fabric substrate (2) are superimposed and fed together to a calender, which comprises a felt (4) capable of providing a set pressure (Pset) in the transfer step. The calender further comprises a lamination cylinder (5) adapted to provide a pressure impulse (Pimpulse) to the superimposed transfer material (1) and substrate (2). In addition to or alternative to the pressure impulse (Pimpulse) provided by the lamination cylinder (5), as specifically shown in Figure 4, the pressure impulse may also be provided by a feed cylinder (6) (sometimes referred to in the art as a feed roller). Exiting the calender is a fabric (3) with at least a base layer still attached. In a subsequent peeling step, this base layer and a portion of the transfer coating can be separated from the fabric to provide a fabric product (not shown). If the method includes calendering, it can be understood that heat may be supplied from a central cylinder (7).

[0057] Another parameter found to affect the transfer yield or yield (or degree of transfer) and quality of the transfer step is the time (hereinafter also referred to as residence time) during which the overlapping, contacted transfer material and fabric substrate are heated and pressed. The residence time should be sufficient to allow for good transfer (in terms of both quality and degree), but ideally not so long as to hinder the overall process speed. Shorter process times are particularly preferred in large-scale production, where the present invention is particularly well suited. Faster process speeds improve production efficiency and reduce production costs per production line. Therefore, the residence time in this process is preferably in the range of 10 to 90 seconds, more preferably 15 to 60 seconds, and most preferably 25 to 50 seconds, for example, about 45 seconds.

[0058] In embodiments involving a pressure impulse, the residence time should be understood as the total time during which pressure is applied to the superimposed transfer material and woven substrate to achieve sufficient transfer. The duration of the pressure impulse is typically much shorter, such as a few seconds, for example, about 0.5 to 5 seconds. Such a short time is sufficient, especially when combined with the pressure applied during the remaining residence time, provided that the surface pressure applied during the pressure impulse is sufficiently high.

[0059] The peeling step is preferably performed within a few seconds, for example, within 20 seconds, more preferably within 10 seconds. The base layer is preferably separated from the woven substrate at a high temperature, most preferably above 50°C, most preferably above 100°C. Thus, the peeling step is preferably a high-temperature peeling step. High-temperature peeling is particularly advantageous for continuous processes and in combination with calendering because it enables high throughput of the woven substrate and pigment transfer material. A cold peeling step requires intermediate cooling of the materials and substrate superimposed after the transfer step, which requires either prolonged or active cooling. Neither is preferable.

[0060] In the peeling step, the base layer is separated from the fabric substrate and at least a portion of the transfer coating. When the transfer efficiency is maximized, all intended portions of the transfer coating and the image printed on it are transferred to the fabric substrate.

[0061] Images of pigments can be printed onto pigment transfer materials by various methods. While the present invention is not limited to a specific printing method, preferred methods may include inkjet printing. The present invention is further limited to specific types of pigments or inks, as bonding to the fabric may be achieved by a transfer coating rather than by the pigment or ink itself. However, the use of self-binding and / or reactive pigments is not excluded and may be even more preferred in some embodiments, particularly when long-lasting and / or highly durable fabric products are desired. A combination of bonding by both the transfer coating and the ink itself can provide exceptional durability. Therefore, sublimation dyes may be used in certain embodiments, especially if such sublimation dyes bond particularly well to the fabric substrate on their own. Other inks that can be suitably used include latex inks and UV-curable inks (see, for example, Stephen Hoath, Fundamentals of Inkjet Printing, Wiley-VCH 2016). All common inkjet inks, latex inks, UV-curable inks, and sublimation inks are printable by inkjet printing. Therefore, these inks are preferable to inks or colorants that cannot be printed by inkjet printing.

[0062] As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context otherwise explicitly indicates otherwise. The term "and / or" includes any combination of one or more of the associated enumerated items. The terms "comprises" and / or "comprising" will be understood to specify the presence of the described features, but not to exclude the presence or addition of one or more other features.

[0063] For the purpose of clarity and concise explanation, features are described herein as part of the same or distinct embodiments, but it will be understood that the scope of the invention may include embodiments having all or some combinations of the described features.

[0064] The present invention can be illustrated using the following non-limiting embodiments.

[0065] Example 1 Pigment transfer materials (papers) A to E are used in transfer coatings with different compositions, as detailed in Table 1, at 85 g / m². 2 Basis weight and 25g / m² 2 The base paper was prepared by coating it with a Cobb value. Each transfer coating was applied individually, at approximately 30 g / m² each. 2 The materials were present in (dry weight) form. Each transfer coating individually had a melting temperature in the range of 150–180°C and a thickness of 25–35 μm.

[0066] The coating was prepared as follows: - Prepare the water, - Add a nonionic wetting agent and a foam inhibitor. - Disperse PE pigment and silica in water. The following was added to this dispersion: - Emulsions of binders and crosslinking agents, - Cationic PU dispersion, -Thickener, - Softener. [Table 1]

[0067] The drying capacity of the coated paper was determined by the following method. - The images were printed in black (K) with 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100% ink coverage. This corresponded to ink levels of 0.36, 0.80, 1.42, 2.14, 2.94, 4.08, 5.23, 6.67, 8.57, and 11.54 ml / m2. The ink used was Kiian Digistar K-Choice 4.0. -The timer was started immediately after printing was complete. -After 5 minutes, at least the printed pigment transfer material test image was 80g / m². 2 Canon Orange Label Performance A4 80g / m² copier paper 2 It was covered with white. - A 10kg roller was used to roll the copier paper covering the test image three times, pressing the copier paper onto the printed pigment transfer material. -The copier paper was separated from the printed pigment transfer material. - We visually checked whether the ink had been transferred from the printed pigment transfer material to the copier paper. The ink level without ink evaporation was recorded as the drying capacity (ml / m2) of the paper after 5 minutes of drying.

[0068] The results are provided in Table 2. [Table 2]

[0069] The woven fabric base obtained by transferring images from papers A to E had a good texture.

[0070] Example 2 Pigment transfer material (paper) containing the following components, 25 g / m² 2 With a single-layer coating, 85g / m 2 Basis weight and 25g / m² 2 The base paper was prepared by coating it with a Cobb value. - 55 parts of polyolefin, - 11 parts of emulsion of binder and crosslinking agent, - 27 parts of cationic polyurethane binder, -5 parts silica pigment, - Antifoaming agent and thickener (partial), -Optionally, 16 parts of a softening agent (quaternary fatty amide or silicone-based).

[0071] Images were printed onto each pigment transfer material using an Epson Stylus Pro 4450 printer and Fujifilm TX440 ink. After printing, print quality and bleeding were determined.

[0072] The image was transferred to a woven fabric substrate using a heat jet transfer calendar (200°C, 30 seconds, 5 bar pressure). The fabric used was 100% cotton warp satin (246g / m²). 2 The results were as follows: After transfer to the fabric, the peeling behavior was observed and the friction fastness was determined. The feel was tested using a test panel. Furthermore, using CH2I2 and water as liquids, the total free surface energy, dispersion, and polar surface energy were determined according to ISO 19403-2:2017. The gloss level (GU) was determined at an 85° angle according to DIN EN ISO 2813-2015-02, and the smoothness was determined using a Gurley tester (standard pressure) according to ISO 5636 / 5. The results are provided in Table 3. [Table 3]

Claims

1. A pigment transfer material suitable for transferring an image onto a textile substrate, wherein the transfer material comprises a base layer and a transfer coating, and the transfer coating has a thickness in the range of 10 to 50 μm and / or a melting temperature in the range of 140 to 210°C.

2. The pigment transfer material according to claim 1, wherein the transfer coating has a thickness in the range of 25 to 40 μm, preferably in the range of 30 to 35 μm, and / or a melting temperature in the range of 150 to 190°C, preferably in the range of 160 to 180°C.

3. The transfer coating is at least 15 g / m² ２ Preferably at least 25 g / m² ２ Preferably at least 30 g / m ２ A pigment transfer material according to any one of the prior claims, present in an amount of [amount].

4. The pigment transfer material according to any one of the prior claims, wherein the transfer coating comprises a polyolefin, preferably polyethylene, more preferably low-density polyethylene (LDPE) and / or high-density polyethylene (HDPE), most preferably HDPE.

5. The pigment transfer material according to any one of the prior claims, wherein the transfer coating comprises a softener, silica, a binder, a wetting agent, a thickener, and / or an antifoaming agent.

6. The pigment transfer material according to any one of the prior claims, wherein the transfer coating comprises a pneumatic agent preferably selected from the group consisting of silicones, fatty acids, fatty amides, and / or paraffin pneumatic agents.

7. The aforementioned transfer coating -50 to 100 parts by weight of the polyolefin, -80 to 130 parts by weight of the binder, - 20 to 50 parts by weight of the softening agent, - Containing 2 to 20 parts by weight of silica, The pigment transfer material according to any one of the prior claims, wherein the binder, the softener, and the silica are each individually relative to 100 parts by weight of the polyolefin.

8. The base layer is base paper, preferably base paper having a basis weight of 60 g / m ２ to 100 g / m ２ , more preferably base paper having a basis weight of 70 g / m ２ to 90 g / m ２ , most preferably base paper having a basis weight of 80 g / m ２ to 90 g / m ２ , and the pigment transfer material according to any one of the preceding claims, including base paper having a basis weight of

9. The base layer is 15 to 50 g / m² ２ The Cobb value, more preferably 20 to 40 g / m² ２ For example, about 25 g / m ２ A pigment transfer material according to any one of the prior claims, having a Cobb value of .

10. The pigment transfer material according to any one of the prior claims, wherein the base layer has a porosity of up to 300 ml / min, preferably up to 280 ml / min, and more preferably up to 250 ml / min, as determined by ISO 5636-3.

11. A pigment transfer material according to any one of the prior claims, comprising the base layer and the transfer coating.

12. A process for transferring an image from a pigment transfer material to a textile substrate to provide a textile product bearing the image, - To provide a pigment transfer material comprising a base layer and a transfer coating, wherein an image of a pigment is provided on the transfer coating, preferably the pigment transfer material according to any one of the prior claims, - A superimposing step including bringing the transfer coating into contact with the fabric substrate, thereby superimposing the pigment transfer material and the fabric substrate, - A transfer step comprising applying pressure and heat to the overlapping, contacting transfer material and fabric substrate, wherein the heat is supplied from a heat source facing the transfer coating, A process comprising a peeling step, which includes separating the base layer from at least a portion of the woven fabric substrate and the transfer coating.

13. The process according to claim 12, wherein the overlapping, contacting transfer material and fabric substrate are heated in the transfer step to a temperature in the range of 100 to 250°C, preferably in the range of 150 to 210°C, more preferably in the range of 160 to 200°C, and most preferably in the range of 180 to 190°C.

14. The process according to claim 12 or 13, wherein the overlapping, contacting transfer material and fabric substrate are heated in the transfer step for a time in the range of 10 to 90 seconds, preferably 15 to 60 seconds, more preferably 25 to 50 seconds, for example, about 45 seconds.

15. The process according to any one of claims 12 to 14, wherein the base layer is separated from the woven fabric substrate at a high temperature, preferably above 50°C, and more preferably above 100°C, in the peeling step.

16. The process according to any one of claims 12 to 15, wherein the process includes calendering.

17. Applying the pressure provided in the transfer step results in a surface pressure impulse, preferably at least 0.03 N / mm². ２ Preferably at least 0.05 N / mm ２ For example, at least 0.06 N / mm ２ The process according to any one of claims 12 to 16, comprising applying a surface pressure impulse.

18. The process according to claim 17, wherein the pressure impulse is applied during the first half of the transfer step, preferably during the first quarter of the transfer step.

19. An aqueous composition for coating a base layer to provide a pigment transfer material, -50 to 100 parts by weight of polyolefin, -80 to 130 parts by weight of binder, -20 to 50 parts by weight of softener, -2 to 20 parts by weight of silica, -Optionally, it includes a thickener, an antifoaming agent, and / or a wetting agent. An aqueous composition in which the binder, the softener, and the silica are each individually relative to 100 parts by weight of the polyolefin.

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