A dtf stencil film and a method of manufacturing the same

Abstract

A DTF film and a preparation method thereof, comprising a back coating layer, a PET film layer, a bottom coating layer and a surface coating layer, the back coating glue comprises a first water-based polyurethane emulsion, a first matte powder, a first wax powder, a first dispersing agent, a first wetting agent and a first defoaming agent; the bottom coating glue comprises a water-based silicone resin emulsion, a second dispersing agent, a second defoaming agent, a second matte powder, a water-based thickening agent, a second wetting agent, a first leveling agent; the surface coating glue comprises a water-based cationic resin liquid, a second water-based polyurethane emulsion, a matt powder, a second wax powder, a third wetting agent, a slip agent, a third defoaming agent, a third dispersing agent, an anti-cratering agent, a second leveling agent, ethanol and an anti-settling agent. The DTF film of the present application has a light and thin coating, uniform and consistent layers, no vertical printing, line printing, mesh printing, cloud-like printing and the like during printing, no lightning printing after bending, can realize hot tearing, second tearing and cold tearing during high-temperature transfer printing, the pattern color is clear and complete after transfer printing, and the hand feeling and wear resistance are good.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of printing materials, in particular to a DTF heat transfer film and a preparation method thereof. BACKGROUND

[0002] The heat transfer film is a material that transfers text or patterns to the surface of other objects by high temperature, especially to fabrics, which can be used for customized design of T-shirts, hats, bed sheets, tablecloths, etc., and has a very wide range of applications. The DTF heat transfer film is a substrate specially designed for white ink heat transfer printing, which transfers patterns to fabrics or other materials using the heat transfer principle. The DTF heat transfer film is mainly used in the clothing industry, which transfers images to fabrics through a high-temperature transfer process. Generally, the desired pattern is designed on a computer in advance, printed on the DTF heat transfer film by a DTF printer, then the hot melt adhesive powder is scattered by a powder shaking machine and baked at high temperature to fix the color, and then the pattern is transferred to the fabric by high-temperature melting of the hot melt adhesive powder.

[0003] The DTF heat transfer film directly determines the transfer quality of white ink heat transfer printing. The heat transfer film needs to print the designed images on the film first, and then transfer the printed images to the surface of the target material. Therefore, the heat transfer film acts as an intermediate carrier. On the one hand, it needs to clearly and stably print the images, and the images need to have a certain adhesion on it. On the other hand, it needs to easily, stably and completely transfer the images on it to the target material, and the adhesion of the images on it cannot be too large. Therefore, the heat transfer film has certain requirements in terms of ink absorption and fixation, adhesion of coating and printing layer, printing stability, powder shaking, release, anti-blocking, temperature resistance, etc. so as to obtain clear, stable and flawless transferred images. The existing DTF heat transfer film often needs to wait for the film to cool down before tearing off after transfer; some can achieve hot tearing and second tearing, but when tearing off, some fine patterns (such as thin lines and small dots) often appear torn or broken; some have the problems of unclear transferred patterns, bright reflection, pinhole defects, and poor wear resistance and rubbing resistance, which easily returns to oil and sticks, etc., affecting the quality of the entire product. The main reason for these problems is that in addition to the ink itself, the compatibility, coordination, adhesion and adsorption of the raw materials of each coating are not balanced, and they are difficult to cooperate and coordinate with each other. Therefore, research needs to be strengthened in the raw material formula and preparation method of each coating. SUMMARY

[0004] The present application aims to overcome the above-mentioned shortcomings of the prior art, and provides a DTF iron-on film, which can realize hot tearing, cold tearing and second tearing, and the transferred pattern is clear, high in color brightness, free of pinholes and screen printing, has no water and oil reverse phenomenon for a pure black color image, can realize printing on the same day, has no change in the image after 7 days, and has the same effect as the printing and transferring on the same day.

[0005] The present application also provides a method for preparing the DTF iron-on film.

[0006] The present application is realized by the following technical solutions:

[0007] A DTF iron-on film, taking PET as a substrate, can resist high temperature, is coated in three layers to form a structure including a back coating layer, a PET film layer, a bottom coating layer and a surface coating layer in sequence, the back coating layer is coated on the back of the PET film layer, the coating amount is 1.0-3.0 g / m 2 , the bottom coating layer is coated on the front of the PET film layer, the coating amount is 1.0-3.0 g / m 2 , and the surface coating layer is coated on the bottom coating layer, the coating amount is 2.0-5.0 g / m 2 , and the surface coating layer is used for printing text and graphics thereon. The thickness of the PET film can be selected according to requirements, and can be 0.05-0.1 mm.

[0008] The back coating layer is prepared from a back coating adhesive, and the back coating adhesive includes the following raw materials in parts by weight: 60-90 parts of a first water-based polyurethane emulsion, 8-15 parts of a first matte powder, 2-5 parts of a first wax powder, 0.3-0.8 parts of a first dispersing agent, 0.6-1.2 parts of a first wetting agent, 0.4-0.8 parts of a first defoaming agent, and 30-40 parts of water. The purpose of the back coating is to form a matte layer to prevent slipping during printing and ensure printing quality, and also to prevent adhesion between the surface coating layer and the back coating layer during winding of the iron-on film, or adhesion between the iron-on film and the hot melt adhesive layer or the ink layer after printing and powdering of the iron-on film.

[0009] The primer layer is prepared from a primer adhesive, which comprises the following raw materials in parts by weight: 100-150 parts of water-based silicone resin emulsion, 0.5-1.5 parts of second dispersant, 0.5-1.5 parts of second defoaming agent, 10-20 parts of second mat powder, 0.3-0.8 parts of water-based thickening agent, 0.5-1.0 parts of second wetting agent, 0.03-0.08 parts of first leveling agent, and 15-20 parts of water. The purpose of the primer is to form a release layer, so that the printed pattern can be easily peeled off from the PET film, whether it is hot or cold, it can be torn off in seconds without residue, to ensure the quality of the transfer, and at the same time, after the transfer is peeled off, the primer layer becomes the surface layer of the pattern, and the surface properties of the primer layer also directly affect the quality of the pattern, such as appearance gloss, wear resistance, and brightness of the pattern. In addition, since the topcoat layer is relatively thin, the ink will penetrate into the primer layer through the topcoat layer, so the primer layer also plays a role in absorbing ink to some extent, which affects the quality of the transferred pattern, especially for water-based ink with smaller viscosity and greater flowability, the performance of the primer layer also affects the quality of the printed pattern.

[0010] In the primer adhesive, the second dispersant helps to disperse, especially for the dispersion of inorganic fillers, which is a surfactant component, which can improve the surface properties of inorganic fillers, make them well compatible with other components, and avoid agglomeration and sedimentation. The role of the water-based thickening agent is to adjust the viscosity of the system, which is conducive to dispersion and compatibility, and balance the flowability of the system, so as to achieve the ideal coating amount. The wetting agent is used to improve the spreading property of the adhesive on the film, and also has a certain effect on the dispersion of inorganic fillers. The leveling agent is used to improve the flowability of the adhesive on the film, so that the adhesive spreads uniformly on the film.

[0011] The topcoat layer is prepared from a topcoat adhesive, which comprises the following raw materials in parts by weight: 50-80 parts of aqueous cationic resin solution, 8-20 parts of second aqueous polyurethane emulsion, 5-10 parts of flatting powder, 2-5 parts of second wax powder, 0.8-1.5 parts of third wetting agent, 0.8-1.5 parts of slip agent, 0.5-1.2 parts of third defoaming agent, 0.3-0.8 parts of third dispersing agent, 0.3-0.8 parts of anti-cratering agent, 0.03-0.08 parts of second leveling agent, 0.8-1.5 parts of ethanol, 0.3-0.5 parts of anti-settling agent, and 5-10 parts of water. The purpose of topcoating is to form an ink-absorbing layer, so that the printing ink can be well attached thereon, and the performance thereof directly affects the quality of printed images. The excellent adsorption of the topcoat layer to the printing ink can ensure that the printing ink does not exude outside the printing area, and the pattern is clear; the wetting type, leveling property and shrinkage of the topcoat adhesive affect the uniformity of the topcoat layer, and the uniformity of the topcoat layer also affects the consistency of the printed pattern, and determines the occurrence of defects such as vertical printing, line printing, mesh printing, spots, mottling, cloud pattern, etc. on the pattern; the topcoat layer cannot be sticky, which on the one hand will adhere to the backcoat layer, and on the other hand will make the non-printing area stick to the hot melt adhesive powder and not easy to shake off; the transparency, gloss, thickness, etc. of the topcoat layer will all affect the appearance and use performance of the transfer printed pattern, too thick will make the coating hard, affect the hand feeling, easy to warp, also affect the brightness of the pattern, too thin will appear ink leakage, and the pattern has poor water resistance and wear resistance.

[0012] It is further preferred that the aqueous cationic resin solution is a cationic modified polyacrylamide solution, the solid content of which is 20%-25%, the pH is 4.0-6.0, and the viscosity at 25℃ is 400-500 mPa·s.

[0013] It is further preferred that the aqueous cationic resin solution is a cationic modified polyacrylamide solution, which is obtained by copolymerization of acrylamide AM, methacryloyloxyethyl trimethyl ammonium chloride DMC and dimethyl diallyl ammonium chloride DMDAAC as comonomers, and persulfate (ammonium persulfate or potassium persulfate) as initiator in an aqueous solution, and a chain transfer agent can be added during the synthesis process to control the molecular weight and viscosity, wherein the mass ratio of acrylamide AM, methacryloyloxyethyl trimethyl ammonium chloride DMC and dimethyl diallyl ammonium chloride DMDAAC is (4-10):1:(0.1-0.5). Methacryloyloxyethyl trimethyl ammonium chloride DMC and dimethyl diallyl ammonium chloride DMDAAC are both cationic monomers, and dimethyl diallyl ammonium chloride DMDAAC also has a certain crosslinking effect, forming a certain network structure, so that the topcoat layer has good compactness and strength, and no residue will be left during high-temperature transfer printing; at the same time, the network structure can better absorb the printing ink.

[0014] The cationic resin can interact with the anionic water-based ink to enhance the adsorption effect on the water-based ink; the cationic resin solution is an acrylamide polymer, which has good hydrophilicity, and the main component of the water-based ink is generally an acrylate polymer, which can be well compatible with the acrylamide polymer and can enhance the interaction between the two by hydrogen bond force, further enhancing the adhesion of the ink on the top coating layer, so that the water-based ink does not spread or penetrate into the non-printing area, making the pattern clear and free of pinholes and mottling.

[0015] The cationic modified polyacrylamide solution is combined with the second water-based polyurethane emulsion, flatting powder, second wax powder, slip agent and other components to make the top coating layer have good ink absorption performance, bright printing color and excellent transferability.

[0016] Further preferably, the first water-based polyurethane emulsion is a non-ionic polyether type polyurethane emulsion, which has a solid content of 38%-42%, a pH value of 7.0-9.0 and a viscosity of 400-500 mPa·s at 25℃.

[0017] The first water-based polyurethane emulsion can form a good film on the PET film, has good adhesion and high strength, and is not prone to sticking with the top coating layer or the hot melt adhesive layer during winding, such as the wax powder and flatting powder in the primer adhesive, which can improve the roughness and anti-sticking property of the back coating layer, the first dispersant can improve the dispersibility of the flatting powder and wax powder in the system, and the first wetting agent can improve the wetting property of the adhesive on the PET film, so that the coating layer can spread uniformly.

[0018] Further preferably, the second water-based polyurethane emulsion is a cationic modified polyurethane emulsion, which has a solid content of 40%-45%, a pH value of 3.0-5.0 and a viscosity of 300-500 mPa·s at 25℃.

[0019] The water-based polyurethane itself has good film-forming property, high strength and good ink absorption, and the cationic modified polyurethane emulsion can further improve the fastness, adhesion, stability and hydrolysis resistance of the coating layer, and can interact with the anionic water-based ink to lock the ink droplets well, so that the ink does not overflow and penetrate, the printed pattern is clear and stable, and the color saturation is higher and brighter. The cationic modified polyurethane can form a network cross-linked structure during film formation, which can fix the ink in the network structure and form hydrogen bonds with the water-based ink, further fixing the ink.

[0020] Further preferred technical solutions are that the water-based silicone resin emulsion is prepared by taking methyl silicone oil, polyethylene wax, hydrogen-containing silicone oil, platinum catalyst and emulsifier as main raw materials, and has a solid content of 38%-42%, a pH of 7.0-10.0 and a viscosity of 100-200 mPa·s at 25℃. Thickening agent, preservative, dispersant, defoaming agent, water and a small amount of organic solvent can also be added to prepare the water-based silicone resin emulsion which has good adhesion to the PET film and, in combination with the mat powder and dispersant in the primer adhesive, makes the primer layer have the release effect of being torn at will (cold torn, hot torn or second torn).

[0021] Further preferred technical solutions are that the slip agent is a mixture of modified wax powder and optical grade acrylic powder, the modified wax powder is micronized polytetrafluoroethylene wax with a drop point of 120-130℃, a penetration of 0.5 dmm at 25℃ and an average particle size of D50 6.0-7.5 μm, and the optical grade acrylic powder is PMMA powder with a particle size of 800-1500 mesh. The optical grade acrylic powder is an organic substance with excellent paint compatibility, easy dispersion and low sedimentation, and is used in the coating layer to improve the transparency and appearance of the coating layer, make the surface of the transferred pattern fine and smooth, and significantly improve the surface scratch resistance. The slip agent is used in the top coating layer to improve the rheological properties of the paint, improve the coatability, improve the anti-blocking and surface properties of the coating layer, improve the fastness, scratch resistance and wear resistance of the final transferred pattern, improve the gloss and hand feeling of the transferred pattern, and have a certain matting effect.

[0022] Further preferred technical solutions are that the first mat powder and the second mat powder are both silica powder with a particle size of 2-5 μm. The first mat powder is applied in the back coating layer to improve the roughness of the back surface of the PET film, increase the friction with other surfaces, avoid slipping during printing and affect the printing quality, and its small particle size will not scratch other surfaces such as the top coating layer or the ink printing layer. The second mat powder is applied in the primer layer to enhance the absorption of ink, make the printed coating layer have a sense of hierarchy, and when the primer layer is separated from the PET film during transfer printing, the primer layer is the surface layer of the transferred pattern, the second mat powder can improve the surface properties of the pattern, reduce the gloss of the pattern, make the graphic level more obvious, make the pattern hand feeling better, and make the wear resistance and rubbing resistance stronger.

[0023] The matting powder, also known as ink absorbing powder, is applied in the top coating layer, and can simultaneously play the roles of ink absorption and matting. The main role is to absorb printing ink, fix colorant, reduce gloss of the coating layer, and avoid bright light reflection of the transferred pattern. The matting powder can be one or a combination of several of the following: ultra-fine silicon dioxide, talc, aluminum stearate, calcium stearate, and low-molecular thermoplastic resin. Preferably, the matting powder is an organic surface-treated silicon dioxide, more preferably an organic silicon surface-treated silicon dioxide, with an average particle size of D50 5.5-6.0 μm, an oil absorption value of 130-180 g / 100 g, a pH value of 5% water suspension solution of 6-8, a porosity of ≥0.8 ml / g, and a specific surface area of 500-560 m 2 / g. The specific surface area and oil absorption value of the matting powder affect its dispersibility and compatibility. In the present application, the matting powder with a large specific surface area and low oil absorption can improve its dispersibility in the top coating glue water-based system, and even with a high addition amount, has little effect on the viscosity of the system, and can improve the ink absorption. After the silicon dioxide is surface-organically treated, the compatibility with other components is improved, the ink absorption is improved, the dispersibility is further improved, the incident light can be scattered, the matting effect is further achieved, the appearance of the coating layer is transparent, and the coating layer has excellent scratch resistance and wear resistance, which is beneficial to improving the quality of the transferred pattern.

[0024] The first wax powder and the second wax powder are respectively used in the back coating layer and the top coating layer, and are low-density polyethylene wax homopolymers. The dropping point of the wax powder is 100-110℃, the viscosity at 120℃ is 800-1200 mPa·s, the penetration at 25℃ is 2-3 dmm, and the acid value is 15-20 mg KOH / g. The low hot melt viscosity makes the wax powder have good flowability in the hot melt state, good wetting type, and good affinity with pigments.

[0025] In a further preferred technical solution, the first dispersant, the second dispersant, and the third dispersant all contain a weak anionic polymer containing a pigment affinity group, with a solid content of 38%-42%, a pH value of 6.0-7.5, and a viscosity at 25℃ of 100-500 mPa·s. The pigment affinity group is a hydroxyl group, a carboxyl group, an ether bond, or an amino group. The dispersant has wetting and dispersing effects on pigments and fillers, reduces the viscosity of the glue, and improves the stability.

[0026] The first defoaming agent, the second defoaming agent, and the third defoaming agent are all compositions of non-ionic surfactants, at least one of which is a non-ionic defoaming agent containing dimethyl polysiloxane.

[0027] The first wetting agent, the second wetting agent, and the third wetting agent are all silicone-based wetting agents, with a viscosity at 25℃ of 300-800 mPa·s.

[0028] The aqueous thickening agent is an associative thickening agent, preferably a non-ionic polyurethane associative thickening agent, which establishes and stabilizes viscosity by forming a network structure between the resin and filler particles, can form a three-dimensional network structure, and can form hydrogen bonding to achieve thickening results, and the thickening is not affected by pH.

[0029] The anti-cratering agent is a siloxane double surfactant containing a siloxane segment and an organic group, the siloxane segment can make it have good wetting type and surface tension, and the organic group can promote its adsorption and diffusion on the surface to prevent the occurrence of craters, so the siloxane double surfactant has high activity, and has the functions of substrate wetting and anti-cratering, and flow promotion and defoaming.

[0030] The anti-settling agent is an aqueous polyurea anti-settling agent, which forms a three-dimensional network structure in the sizing material, can produce thixotropic flow performance, prevents the settling of pigments and fillers during storage, and restores good flowability after gentle stirring during use, has less effect on the viscosity of the system compared to the thickening agent, is easy to use, does not need to control temperature and pH value, and can also improve the leveling property, which is beneficial to the coating operation.

[0031] A preparation method of the above-mentioned DTF transfer film, comprising the following steps:

[0032] S1, after the back coating glue is prepared, the back surface of the PET film is first coated on the coating equipment to form a back coating layer, the back coating is carried out by reverse coating with a screen roller, and the coating is carried out while winding, the coating speed is 80-100 m / min, the oven temperature is 80-150℃, the oven residence time is ≤1 min, and the back coating layer is detected after curing for 12-24 h, including coating amount detection and appearance detection. The sanding effect is more uniform by reverse coating with a screen roller, and the screen printing will appear when coating.

[0033] S2, after the primer glue is prepared, the front surface of the PET film is coated on the coating equipment to form a primer layer, the primer coating is carried out by reverse coating with a screen roller, and the coating is carried out while winding, the coating speed is 50-70 m / min, the oven temperature is 80-180℃, the oven residence time is ≤1 min, and the back coating layer is detected after curing for 12-24 h, including coating amount detection and appearance detection. The leveling property of reverse coating is better.

[0034] S3, after the top coating glue is prepared, the primer layer of the PET film is top coated on the coating equipment to form a top coating layer, the top coating is carried out by reverse coating with a screen roller, and the coating is carried out while winding, the coating speed is 50-70 m / min, the oven temperature is 80-180℃, the oven residence time is ≤1 min, and the back coating layer is detected after curing for 12-24 h, including appearance, coating amount and coating performance detection. The reverse coating is more uniform and the surface is free of vertical printing, line printing, screen printing and cloudiness.

[0035] The base coat of the present application takes water-based silicone resin emulsion, matt powder, water-based thickening agent, dispersant and the like as raw materials of the base coat adhesive, through the special structure and components of the water-based silicone resin emulsion and the interaction and cooperation between the other components, the base coat has suitable adhesion to the PET film, has certain adhesion during coating to form a coating, and can be easily separated from the film during transfer, is not affected by temperature, and achieves the release effect of tearing at will; meanwhile, can give the transferred pattern good appearance gloss performance, hand feeling, water resistance, wear resistance and rubbing resistance; and cooperates with the top coat to give the iron-on film good ink absorption performance, so that the transferred pattern has rich level and hand feeling.

[0036] The top coat of the present application takes water-based cationic resin liquid, polyurethane emulsion, matt powder, wax powder, slip agent, anti-cratering agent, anti-settling agent, ethanol, dispersant and the like as raw materials of the top coat adhesive, the special structure of the water-based cationic resin liquid and the polyurethane emulsion enables them to interact with the water-based ink, the ink can be fixed in the three-dimensional network structure, the component structure of the slip agent, wax powder and matt powder can improve the ink absorption of the coating, and the cooperation of the components enables the top coat to quickly and efficiently absorb the water-based ink, the ink does not appear diffusion, overflow and the like, and improves the printing quality, and the pattern is clear and defect-free.

[0037] The back coat of the present application takes water-based polyurethane emulsion, matt powder, wax powder and the like as raw materials of the back coat adhesive, gives the back coat suitable surface roughness and anti-sticking property, and meets the use requirements.

[0038] The DTF iron-on film prepared by the present application has light and thin coating, is economical and applicable, the reasonable use of wetting agent, dispersant, defoaming agent and the like in each coating layer makes each coating layer uniform and consistent, no vertical printing, line printing, mesh printing, cloud-like appearance and the like appears during printing, and no obvious lightning printing appears after bending; the pattern of high-temperature transfer can realize hot tearing, second tearing and cold tearing, and can realize second tearing without waiting for cooling after high-temperature transfer; the transferred pattern has clear and complete color, no pinhole, no bending and no edge lifting; the transferred pattern has suitable gloss, does not reflect light and is bright, has rich level, good hand feeling and good wear resistance; the iron-on film does not stick powder on the non-image area, and the back matt layer can effectively prevent slipping. DETAILED DESCRIPTION

[0039] A DTF iron-on film takes PET as a substrate, is resistant to high temperature, is coated in three layers, and forms a structure of back coat, PET film layer, base coat and top coat in sequence, the back coat is coated on the back of the PET film layer, the coating amount is 1.0-3.0 g / m 2 , the base coat is coated on the front of the PET film layer, the coating amount is 1.0-3.0 g / m 2 , and the top coat is coated on the base coat, the coating amount is 2.0-5.0 g / m 2The surface coating layer is used for graphic printing thereon. The thickness of the PET film can be selected as required, and can be 0.05-0.1 mm.

[0040] The back coating layer is prepared from a back coating adhesive, and the back coating adhesive comprises the following raw materials in parts by weight: 60-90 parts of a first water-based polyurethane emulsion, 8-15 parts of a first mat powder, 2-5 parts of a first wax powder, 0.3-0.8 parts of a first dispersing agent, 0.6-1.2 parts of a first wetting agent, 0.4-0.8 parts of a first defoaming agent, and 30-40 parts of water.

[0041] The base coating layer is prepared from a base coating adhesive, and the base coating adhesive comprises the following raw materials in parts by weight: 100-150 parts of a water-based silicone resin emulsion, 0.5-1.5 parts of a second dispersing agent, 0.5-1.5 parts of a second defoaming agent, 10-20 parts of a second mat powder, 0.3-0.8 parts of a water-based thickening agent, 0.5-1.0 parts of a second wetting agent, 0.03-0.08 parts of a first leveling agent, and 15-20 parts of water.

[0042] The surface coating layer is prepared from a surface coating adhesive, and the surface coating adhesive comprises the following raw materials in parts by weight: 50-80 parts of a water-based cationic resin solution, 8-20 parts of a second water-based polyurethane emulsion, 5-10 parts of a matting powder, 2-5 parts of a second wax powder, 0.8-1.5 parts of a third wetting agent, 0.8-1.5 parts of a slip agent, 0.5-1.2 parts of a third defoaming agent, 0.3-0.8 parts of a third dispersing agent, 0.3-0.8 parts of an anti-cratering agent, 0.03-0.08 parts of a second leveling agent, 0.8-1.5 parts of ethanol, 0.3-0.5 parts of an anti-settling agent, and 5-10 parts of water.

[0043] The water-based cationic resin solution is a cationic modified polyacrylamide solution, has a solid content of 20%-25%, a pH of 4.0-6.0, and a viscosity of 400-500 mPa·s at 25℃. The cationic modified polyacrylamide solution is obtained by copolymerization of acrylamide AM, methacryloyloxyethyltrimethylammonium chloride DMC, and dimethyldiallylammonium chloride DMDAAC as comonomers, with persulfate (ammonium persulfate or potassium persulfate) as an initiator in an aqueous solution. A chain transfer agent can be added during the synthesis process to control the molecular weight and viscosity. The mass ratio of acrylamide AM, methacryloyloxyethyltrimethylammonium chloride DMC, and dimethyldiallylammonium chloride DMDAAC is (4-10):1:(0.1-0.5).

[0044] The first water-based polyurethane emulsion is a non-ionic polyether type polyurethane emulsion, has a solid content of 38%-42%, a pH of 7.0-9.0, and a viscosity of 400-500 mPa·s at 25℃.

[0045] The second aqueous polyurethane emulsion is a cationic modified polyurethane emulsion, with a solid content of 40%-45%, a pH of 3.0-5.0, and a viscosity of 300-500 mPa·s at 25°C.

[0046] The aqueous silicone emulsion is prepared from methyl silicone oil, polyethylene wax, hydrogen-containing silicone oil, platinum catalyst, and emulsifier as main raw materials, and can further contain thickening agent, preservative, dispersant, defoaming agent, water, and a small amount of organic solvent as needed, with a solid content of 38%-42%, a pH of 7.0-10.0, and a viscosity of 100-200 mPa·s at 25°C.

[0047] The slip agent is a mixture of modified wax powder and optical grade acrylic powder, the modified wax powder is micronized polytetrafluoroethylene wax with a drop point of 120-130°C, a penetration of 0.5 dmm at 25°C, and an average particle size of D506.0-7.5 μm, and the optical grade acrylic powder is PMMA powder with a particle size of 800-1500 mesh.

[0048] The first and second matting powders are both silica powders with a particle size of 2-5 μm.

[0049] The matting powder is silicone surface-treated silica with an average particle size of D505.5-6.0 μm, an oil absorption value of 130-180 g / 100 g, a pH value of 5% aqueous suspension solution of 6-8, a porosity of ≥0.8 ml / g, and a specific surface area of 500-560 m 2 / g.

[0050] The first and second wax powders are used in the back coating layer and the top coating layer respectively, and are low-density polyethylene wax homopolymers with a drop point of 100-110°C, a viscosity of 800-1200 mPa·s at 120°C, a penetration of 2-3 dmm at 25°C, and an acid value of 15-20 mg KOH / g.

[0051] The first, second, and third dispersants all contain weak anionic polymers containing pigment-affinity groups, with a solid content of 38%-42%, a pH value of 6.0-7.5, and a viscosity of 100-500 mPa·s at 25°C, and the pigment-affinity groups are hydroxyl, carboxyl, ether bond, or amino.

[0052] The first, second, and third defoaming agents are all compositions of non-ionic surfactants, at least one of which is a non-ionic defoaming agent containing dimethyl polysiloxane.

[0053] The first, second, and third wetting agents are all silicone-based wetting agents with a viscosity of 300-800 mPa·s at 25°C.

[0054] The aqueous thickener is an associative thickener, preferably a non-ionic polyurethane associative thickener.

[0055] The anti-cratering agent is a silicone bis-surfactant containing a silicone segment and an organic group.

[0056] The anti-settling agent is an aqueous polyurea anti-settling agent.

[0057] The types, manufacturers, models, and specification parameters of the raw materials used in this example are as follows:

[0058] 1. Aqueous cationic resin liquid, a product of a certain company with a model number of H436, which is a slightly yellowish translucent liquid, has a solid content of 21%, a pH value of 4.0-6.0, and a viscosity of 400-500 mPa-s at 25°C.

[0059] 2. Aqueous polyurethane emulsion: a first aqueous polyurethane emulsion is a product of a certain company with a model number of H420, which is a milky white liquid, has a solid content of 40%, a pH value of 7.5-8.0, and a viscosity of 350-450 mPa-s at 25°C. A second aqueous polyurethane emulsion is a product of a certain company with a model number of H421, which is a milky white liquid, has a solid content of 42%, a pH value of 3.5-5.0, and a viscosity of 350-450 mPa-s at 25°C.

[0060] 3. Aqueous silicone resin emulsion: a product of a certain company with a model number of A449, which is a milky white liquid, has a solid content of 40%, a pH value of 7.0-10.0, and a viscosity of 150-200 mPa-s at 25°C.

[0061] 4. Slip agent: modified wax powder is Honeywell wax powder 3105B, and optical grade acrylic powder is PMMA LP-3105 product of Mitsubishi Rayon.

[0062] 5. Matt powder: a product of a certain company with a model number of HU80.

[0063] 6. Wax powder: first and second wax powders, both of which are polyethylene wax with a model number of A8W.

[0064] 7. Matt powder: first and second matt powders, both of which are silica powder with a model number of DT-677.

[0065] 8. Anti-settling agent: a product with a model number of Anjeka 4420.

[0066] 9. Aqueous thickener: a product with a model number of TAFIGEL® PUR44.

[0067] 10. Anti-cratering agent: a product of Degussa with a model number of TEGO Twin 4100.

[0068] 11. Dispersants: the first, second and third dispersants are all selected from the product of type Dispers 755W of the company DKS.

[0069] 12. Wetting agents: the first, second and third wetting agents are selected from the series of products WSS-713, WSS-7201, WSS-750, etc., used alone or in combination.

[0070] 13. Defoamers: the first, second and third defoamers are selected from SILCOLAPSE™ 5020, SILCOLAPSE™ C525, SILCOLAPSE™ C585, surfynol AD 01, surfynol 465, surfynol 104e, etc., used alone or in combination.

[0071] 14. Leveling agents: the first and second leveling agents are selected from Dow Corning DC-51, DC-57, DCA-1091, etc.

[0072] A preparation method of the above-mentioned DTF iron-on film, comprising the following steps:

[0073] S1. After preparing the back coating adhesive, the back surface of the PET film is first back coated on the coating equipment to form a back coating layer. The back coating is carried out by reverse coating with an anilox roller, and the coating is rolled up at the same time. The coating speed is 90-110 m / min, the oven temperature is 80-150℃, the oven residence time is ≤1 min, and the back coating layer is cured for 12-24 h before detection, including coating amount detection and appearance detection.

[0074] S2. After preparing the base coating adhesive, the front surface of the PET film is base coated on the coating equipment to form a base coating layer. The base coating is carried out by reverse coating with an anilox roller, and the coating is rolled up at the same time. The coating speed is 50-70 m / min, the oven temperature is 80-180℃, the oven residence time is ≤1 min, and the back coating layer is cured for 12-24 h before detection, including coating amount detection and appearance detection.

[0075] S3. After preparing the top coating adhesive, the base coating layer of the PET film is top coated on the coating equipment to form a top coating layer. The top coating is carried out by reverse coating with an anilox roller, and the coating is rolled up at the same time. The coating speed is 50-70 m / min, the oven temperature is 80-180℃, the oven residence time is ≤1 min, and the back coating layer is cured for 12-24 h before detection, including appearance, coating amount and coating performance detection.

[0076] Example 1

[0077] The back coating layer is reverse coated by a gravure roll with a coating weight of 1.8 g. Taking 135 kg of the back coating adhesive as an example, the solid content thereof is 48%, and the raw material components are shown in Table 1. The first defoaming agent is a mixture of SILCOLAPSE™ 5020 and surfynol AD 01, and the first wetting agent is a combination of WSS-7201 and WSS-713.

[0078] Table 1 Formula of the back coating adhesive

[0079]

[0080] The raw material formula is: first water-based polyurethane emulsion 82.4 kg, first dispersing agent 0.5 kg, first defoaming agent 0.6 kg, first mat powder 9.4 kg, first wax powder 3 kg, first wetting agent 0.1 kg, and water 38.1 kg.

[0081] The base coating layer is reverse coated by a gravure roll with a coating weight of 1.5 g. Taking 156 kg of the base coating adhesive as an example, the solid content thereof is 38%, and the raw material components are shown in Table 2. The second defoaming agent is a mixture of SILCOLAPSE™ 5020 and surfynol 465, and the second wetting agent is WSS-713.

[0082] Table 2 Formula of the base coating adhesive

[0083]

[0084] The top coating layer is reverse coated by a gravure roll with a coating weight of 2.5 g. Taking 100 kg of the top coating adhesive as an example, the raw material components are shown in Table 3. The third defoaming agent is a mixture of SILCOLAPSE™ 5020 and surfynol AD 01, and the third wetting agent is a combination of WSS-7201 and WSS-750.

[0085] Table 3 Formula of the top coating adhesive

[0086]

[0087] Example 2

[0088] The back coating layer is reverse coated by a gravure roll with a coating weight of 1.6 g. Taking 135 kg of the back coating adhesive as an example, the solid content thereof is 48%, and the raw material components are shown in Table 4. The first defoaming agent is a mixture of SILCOLAPSE™ C525 and surfynol AD 01, and the first wetting agent is WSS-7201.

[0089] Table 4 Formula of the back coating adhesive

[0090]

[0091] The base coat was reverse roll coated at 1.4g, for example, 156kg of base coat with 38% solid content, the raw material ingredients are shown in Table 5, wherein the second defoamer is a mixture of SILCOLAPSE™ C525 and surfynol 465, and the second wetting agent is a combination of WSS-7201 and WSS-750.

[0092] Table 5 Formulation of base coat

[0093]

[0094] The top coat was reverse roll coated at 2.6g, for example, 100kg of top coat, the raw material ingredients are shown in Table 6, wherein the third defoamer is a mixture of SILCOLAPSE™ 5020 and surfynol AD01, and the third wetting agent is a combination of WSS-7201 and WSS-713.

[0095] Table 6 Formulation of top coat

[0096]

[0097] Example 3

[0098] The back coat was reverse roll coated at 2g, for example, 135kg of back coat with 48% solid content, the raw material ingredients are shown in Table 7, wherein the first defoamer is a mixture of SILCOLAPSE™ 5020 and surfynol 104e, and the first wetting agent is a combination of WSS-750 and WSS-713.

[0099] Table 7 Formulation of back coat

[0100]

[0101] The base coat was reverse roll coated at 1.7g, for example, 156kg of base coat with 38% solid content, the raw material ingredients are shown in Table 8, wherein the second defoamer is a mixture of SILCOLAPSE™ 5020 and surfynol 104e, and the second wetting agent is a combination of WSS-7201 and WSS-713.

[0102] Table 8 Formulation of base coat

[0103]

[0104] The topcoat layer is reverse coated by an anilox roller, and the coating amount is 2.8 g. Taking 100 kg of the topcoat adhesive as an example, the raw material components are shown in Table 9, wherein the third defoaming agent is a mixture of SILCOLAPSE™ 5020 and surfynol AD 01, and the third wetting agent is WSS-713.

[0105] Table 9 Formulation of the topcoat adhesive

[0106]

[0107] Product testing:

[0108] The products after coating, drying and curing of Examples 1-3 are sampled for testing, and the quality is qualified according to the quality testing standards formulated by the company. The testing results are shown in Table 10.

[0109] Table 10 Testing results according to the enterprise standard

[0110]

[0111] The same type of products on the market are taken as comparative examples, and the products of the present embodiment 1 are tested and compared. The testing results are shown in Table 11 according to the relevant testing standards.

[0112] Table 11 Testing results of the examples and comparative examples

[0113]

[0114] As can be seen from Table 10 and Table 11, the DTF iron-on film products obtained by the formulation and preparation method of the present application can all achieve the quality of the product enterprise standard, meet the use requirements, and have more advantages in hot tearing, cold tearing, second tearing, etc. compared with the same type of products on the market. The high-temperature transfer does not need to wait for second tearing and peeling, the transferred pattern is clear and bright as before, and will not become lighter and lighter. The quality is better. At the same time, compared with the same type of products, the present application has more excellent performance in ink fixation and powder sticking, has excellent ink fixation effect, and does not appear phenomena such as ink bleeding and penetration. The clarity and brightness of the printed pattern are better, and the stability of the printed pattern and the transferred pattern can meet the requirements, and phenomena such as reverse water and reverse oil do not occur. And compared with the same type of products on the market, the coating amount of the product of the present application is smaller, the coating is lighter and thinner, and the cost is lower.

[0115] The above detailed description is a specific description of the feasible embodiments of the present application, and this embodiment is not used to limit the patent scope of the present application. Any equivalent implementation or change that does not deviate from the present application should be included in the patent scope of the present application.

Claims

1. A DTF heat transfer film, characterized in that, The coating comprises, in sequence, a back coating layer, a PET film layer, a base coating layer, and a top coating layer. The back coating layer is applied to the back side of the PET film layer, with a coating amount of 1.0-3.0 g / m². 2 The base coating is applied to the front side of the PET film layer, with a coating amount of 1.0-3.0 g / m². 2 The topcoat layer is applied over the basecoat layer, and its coating amount is 2.0-5.0 g / m². 2 The surface coating is used for printing graphics on it; The back coating is prepared by a back coating adhesive, which comprises the following raw materials in parts by weight: 60-90 parts of a first waterborne polyurethane emulsion, 8-15 parts of a first matting powder, 2-5 parts of a first wax powder, 0.3-0.8 parts of a first dispersant, 0.6-1.2 parts of a first wetting agent, 0.4-0.8 parts of a first defoamer, and 30-40 parts of water. The base coating is prepared from a base coating adhesive, which comprises the following raw materials in parts by weight: 100-150 parts of water-based silicone resin emulsion, 0.5-1.5 parts of second dispersant, 0.5-1.5 parts of second defoamer, 10-20 parts of second matting powder, 0.3-0.8 parts of water-based thickener, 0.5-1.0 parts of second wetting agent, 0.03-0.08 parts of first leveling agent, and 15-20 parts of water; The topcoat is prepared by a topcoat adhesive, which comprises the following raw materials in parts by weight: 50-80 parts of aqueous cationic resin liquid, 8-20 parts of second aqueous polyurethane emulsion, 5-10 parts of matting agent, 2-5 parts of second wax powder, 0.8-1.5 parts of third wetting agent, 0.8-1.5 parts of slip agent, 0.5-1.2 parts of third defoamer, 0.3-0.8 parts of third dispersant, 0.3-0.8 parts of anti-cratering agent, 0.03-0.08 parts of second leveling agent, 0.8-1.5 parts of ethanol, 0.3-0.5 parts of anti-settling agent, and 5-10 parts of water; The aqueous cationic resin solution is a cationic modified polyacrylamide solution, which is obtained by copolymerization in aqueous solution using acrylamide AM, methacryloyloxyethyltrimethylammonium chloride DMC and dimethyl diallyl ammonium chloride DMDAAC as comonomers and persulfate as an initiator. The mass ratio of acrylamide AM, methacryloyloxyethyltrimethylammonium chloride DMC and dimethyl diallyl ammonium chloride DMDAAC is (4-10):1:(0.1-0.5). The first aqueous polyurethane emulsion is a nonionic polyether polyurethane emulsion with a solid content of 38%-42%, a pH value of 7.0-9.0, and a viscosity of 400-500 mPa·s at 25°C. The second waterborne polyurethane emulsion is a cationic modified polyurethane emulsion with a solid content of 40%-45%, a pH of 3.0-5.0, and a viscosity of 300-500 mPa·s at 25℃. The raw materials for preparing the aqueous silicone resin emulsion include methyl silicone oil, polyethylene wax, hydrogen-containing silicone oil, platinum catalyst and emulsifier, with a solid content of 38%-42%, a pH of 7.0-10.0, and a viscosity of 100-200 mPa·s at 25°C.

2. The DTF heat transfer film according to claim 1, characterized in that, The aqueous cationic resin solution is a cationic modified polyacrylamide solution with a solid content of 20%-25%, a pH of 4.0-6.0, and a viscosity of 400-500 mPa·s at 25°C.

3. The DTF heat transfer film according to claim 1, characterized in that, The slip agent is a mixture of modified wax powder and optical grade acrylic powder. The modified wax powder is micronized polytetrafluoroethylene wax with a dropping point of 120-130℃, a penetration of 0.5dmm at 25℃, and an average particle size of D50 of 6.0-7.5μm. The optical grade acrylic powder is PMMA powder with a particle size of 800-1500 mesh.

4. The DTF heat transfer film according to claim 1, characterized in that, The matting agent is silicone-treated silica with an average particle size of D50 of 5.5-6.0 μm, an oil absorption value of 130-180 g / 100 g, a pH of 6-8 for a 5% aqueous suspension, a porosity ≥0.8 ml / g, and a specific surface area of ​​500-560 m². 2 / g; The second wax powder is a low-density polyethylene wax polymer with a dropping point of 100-110℃, a viscosity of 800-1200 mPa·s at 120℃, a penetration of 2-3 dmm at 25℃, and an acid value of 15-20 mg KOH / g. Both the first and second matte powders are silica powders with a particle size of 2-5 μm.

5. A DTF heat transfer film according to claim 1, characterized in that, The first, second, and third dispersants all contain weak anionic polymers with pigment affinity groups, with a solid content of 38%-42%, a pH value of 6.0-7.5, and a viscosity of 100-500 mPa·s at 25°C. The pigment affinity groups are hydroxyl, carboxyl, ether, or amino groups. The first defoamer, the second defoamer, and the third defoamer are all compositions of nonionic surfactants, wherein at least one of them is a nonionic defoamer containing dimethyl polysiloxane; The first, second, and third wetting agents are all organosilicon wetting agents with a viscosity of 300-800 mPa·s at 25°C. The anti-cracking agent is a siloxane dual surfactant, which contains siloxane segments and organic groups; The water-based thickener is a nonionic polyurethane associative thickener; the anti-settling agent is a water-based polyurea anti-settling agent.

6. A method for preparing a DTF heat transfer film as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1. After preparing the back coating adhesive, the back of the PET film is first coated on the coating equipment to form a back coating layer. The back coating is applied by an anilox roller in reverse coating, and the film is rolled up while coating. The coating speed is 80-100m / min, the oven temperature is 60-150℃, and the oven dwell time is ≤1min. After the back coating is cured for 12-24h, it is tested, including coating amount test and appearance test. S2. After preparing the primer, apply the primer to the front side of the PET film on the coating equipment to form a primer coating layer. The primer is applied in reverse using an anilox roller, with the film being rolled up while being coated. The coating speed is 50-70 m / min, the oven temperature is 60-165℃, and the oven dwell time is ≤1 min. After the back coating has been cured for 12-24 hours, it is tested, including coating amount test and appearance test. S3. After preparing the top coating adhesive, apply the top coating onto the base coating of the PET film using a coating equipment to form the top coating. The top coating is applied in reverse using an anilox roller, with simultaneous coating and winding. The coating speed is 50-70 m / min, the oven temperature is 60-150℃, and the oven dwell time is ≤1 min. After the back coating has cured for 12-24 hours, it is tested, including the appearance, coating amount, and coating performance.

Images