Ink-jet adhesive for DTF process and preparation method of ink-jet adhesive

Abstract

The invention discloses an ink-jet adhesive for a DTF process and a preparation method thereof, and the ink-jet adhesive for the DTF process comprises the following components in percentage by weight: 5%-15% of a thickening agent, 5%-15% of a solvent, 5%-15% of a solvent, and the balance of a solvent. 65-85% of a polyester emulsion; 0.1-1% of a wetting agent; 0.1%-0.5% of a defoaming agent; 0.1%-0.5% of a leveling agent; in addition, the viscosity of the ink-jet adhesive for the DTF process is 20-500 cP, the pH value is 7.5-8.5, the particle size distribution D50 is smaller than or equal to 200 nm, and the surface tension is 25-45 mN / m.

Description

Technical Field

[0001] This invention relates to the field of digital inkjet printing technology, and in particular to an inkjet adhesive for DTF process and its preparation method. Background Technology

[0002] DTF (Direct to Film) technology involves inkjet printing a pattern onto a release film, which is then transferred to a substrate (such as fabric). The inkjet adhesive acts as the bonding medium, directly affecting the pattern's adhesion, flexibility, and printing smoothness. Currently, there are many types of adhesives on the market, one of which is epoxy adhesive: bisphenol A epoxy resin and amine curing agents. It boasts high bonding strength (shear strength > 20 MPa) and excellent chemical resistance, but also high viscosity (500-1000 cP at room temperature), fast curing speed (< 30 s), and rigidity after curing (elongation at break < 5%). It is mainly used for structural bonding of hard materials such as metals / ceramics, but cannot be used for DTF inkjet printing (it easily clogs the printhead and is not suitable for flexible fabrics).

[0003] Another type is silicone-based adhesive: polydimethylsiloxane derivative; it is resistant to high and low temperatures (-60~200℃) and has good weather resistance, but it has poor compatibility with paints and pigments and low bonding strength (adhesion to fabric <1N / cm); it is mainly used in sealants and release agents, but cannot be used in DTF inkjet printing (the pattern is easy to fall off after transfer).

[0004] Another type is polyurethane emulsion adhesive: a water-based polyurethane dispersion; its viscosity is adjustable (50-300 cP), it has excellent flexibility (elongation at break > 300%), and good compatibility with coatings (pigment dispersion stability > 30 days); it can be applied to textile coatings and leather finishing, and can be used for DTF inkjet printing, but existing products have insufficient water resistance (wash resistance < 30 times). In addition, existing polyurethane emulsion adhesives have insufficient water resistance (wash resistance < 5 times), and acrylic emulsion adhesives have problems such as high-temperature yellowing (yellowing grade > 3 above 120℃), which cannot meet the dual requirements of "high-smooth printing + high-adhesion transfer" in coating DTF.

[0005] Another type is acrylic emulsion adhesive: acrylic copolymer emulsion; it has low cost and good weather resistance, but it is obviously brittle at low temperatures (easily cracks below -10℃) and has poor adhesion to polar substrates (such as nylon) (<2 grade, ASTM D3359); it is mainly used in architectural coatings and paper coatings, and can be used for DTF inkjet printing, but its overall performance is not as good as polyurethane emulsion adhesive.

[0006] There is also nitrile rubber latex: butadiene-acrylonitrile copolymer; it has good oil resistance, but poor viscosity stability (24h fluctuation > 20%), and poor compatibility with water-based coatings (easy to delaminate); it is used for oil-resistant sealing, but cannot be used for DTF inkjet printing (easy to interrupt ink during printing). Summary of the Invention

[0007] To address the aforementioned technical problems, this application provides an inkjet adhesive for DTF processes, wherein the inkjet adhesive for DTF processes uses polyurethane emulsion or acrylic emulsion as a base material, and the formulation optimization solves the problems of poor water resistance, high-temperature yellowing and printing clogging of existing products, making it compatible with industrial-grade inkjet equipment.

[0008] To address the aforementioned technical problems, this application provides an inkjet adhesive for DTF processes, wherein the inkjet adhesive for DTF processes comprises the following components by weight percentage:

[0009] Thickener 5%-15%;

[0010] Polyester emulsion 65-85%;

[0011] Wetting agent 0.1-1%;

[0012] Defoamer 0.1%-0.5%;

[0013] Leveling agent 0.1%-0.5%;

[0014] Fungicide 0.05%-0.2%

[0015] The remainder is deionized water. In addition, the inkjet adhesive used in the DTF process has a viscosity of 20-500 cP, a pH value of 7.5-8.5, a particle size distribution D50≤200nm, and a surface tension of 25-45mN / m.

[0016] According to one embodiment of this application, the thickener is at least one selected from ethylene glycol, propylene glycol, glycerin, PEG200, hydroxyethyl cellulose, and polyglycerol.

[0017] According to one embodiment of this application, the polyester emulsion is at least one of polyurethane emulsion, acrylate emulsion, and polyamide resin.

[0018] According to one embodiment of this application, the polyester emulsion is a polyurethane emulsion adhesive, and the polyurethane emulsion adhesive has the following advantages compared with the acrylic emulsion adhesive:

[0019] According to one embodiment of this application, the polyurethane is an aliphatic polyurethane resin with an average particle size of less than 200 nm, an elongation at break of 300-600%, a Tg value of less than 0 °C, and a resin viscosity of less than 200 MPa.

[0020] According to one embodiment of this application, the wetting agent is a nonionic polyether modified silicone surfactant, such as at least one selected from Evonik's TEGO wet245, wet250, and Dynol 960.

[0021] According to one embodiment of this application, the leveling agent is one of BYK333 and BYK348.

[0022] According to one embodiment of this application, the defoamer is an alkynol defoamer or an organosilicone defoamer, selected from at least one of BYK-025, TEGO-842, Evonik Surfynol 104E, and Surfynol DF-110D.

[0023] According to one embodiment of this application, the bactericide is at least one of PROXEL GXL and Rohm and Haas LEX.

[0024] According to another aspect of this application, this application provides a method for preparing inkjet adhesive for DTF process, the method comprising:

[0025] S101, according to the component ratio of the inkjet adhesive used in the DTF process, add thickener to the reaction vessel and add polyester emulsion while stirring.

[0026] S102, then under stirring, deionized water, wetting agent, defoamer, leveling agent and bactericide are added to the reactor in sequence;

[0027] S103 is then filtered to obtain digital inkjet adhesive. Detailed Implementation

[0028] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0029] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limitations on this invention.

[0030] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0031] According to one aspect of this application, an inkjet adhesive for DTF process according to a preferred embodiment of the present invention will be described in detail below, wherein the inkjet adhesive for DTF process comprises, by weight percentage, the following components:

[0032] Thickener 5%-15%;

[0033] Polyester emulsion 65-85%;

[0034] Wetting agent 0.1-1%;

[0035] Defoamer 0.1%-0.5%;

[0036] Leveling agent 0.1%-0.5%;

[0037] Fungicide 0.05%-0.2%

[0038] The remainder is deionized water. In addition, the inkjet adhesive used in the DTF process has a viscosity of 20-500 cP (measured at 25°C using a rotational viscometer), a pH value of 7.5-8.5, a particle size distribution D50 ≤ 200 nm, and a surface tension of 25-45 mN / m.

[0039] Preferably, the thickener is at least one selected from ethylene glycol, propylene glycol, glycerin, PEG200, hydroxyethyl cellulose, and polyglycerol.

[0040] Preferably, the polyester emulsion is at least one of polyurethane emulsion, acrylate emulsion, and polyamide resin. Examples include Mitsui Chemicals' 6110, Ube Chemicals' 6001D and 1005D, Starr Chemicals' 5523, LianGu's PLAPOLY 0320, PLA poly-1080, BASF-LMV7034, BASF FLX5220 / DFC3025, BASF Joncryl 631, BASF Joncryl 89ap, Impaneil's PU-1606, Huigu's PU-2371, and Weng Kai'er's PU-601.

[0041] More preferably, the polyester emulsion is a polyurethane emulsion adhesive, which has the following advantages over acrylic emulsion adhesives:

[0042] First, flexibility and elasticity: Polyurethane molecular chains consist of soft and hard segments, forming a microscopic phase-separated structure that endows the adhesive film with extremely high elasticity and resilience. Its elongation at break is much higher than that of acrylic emulsion adhesives. This makes polyurethane adhesive layers less prone to cracking or peeling when bent and stretched on flexible substrates (such as elastic fabrics), while acrylic films are relatively rigid and brittle.

[0043] Secondly, wear resistance and scratch resistance: There are strong hydrogen bonds between polyurethane molecules, which can form an effective cross-linking network, making its wear resistance extremely excellent.

[0044] Secondly, adhesion: The polar groups in polyurethane molecules (such as urethane bonds and urea bonds) can form stronger physical and chemical bonds with the surfaces of various substrates, exhibiting excellent adhesion to both polar substrates (such as nylon and polyester) and non-polar substrates (such as PP), making it applicable to a wider range of materials.

[0045] Furthermore, regarding water resistance and washability: waterborne polyurethane emulsions form films with low swelling in water and resistance to water whitening, exhibiting excellent wash fastness on textiles. In contrast, acrylic emulsion adhesives generally have poor water resistance and are prone to whitening and softening upon contact with water.

[0046] In addition, regarding resistance to yellowing: polyurethanes prepared using aliphatic or alicyclic isocyanates do not contain unsaturated double bonds in their molecular structure, exhibiting strong UV resistance and maintaining transparency without yellowing even after long-term outdoor use. Acrylic resins, on the other hand, are prone to oxidation and yellowing under UV light, affecting the aesthetics of the design.

[0047] More preferably, the polyurethane is an aliphatic polyurethane resin with an average particle size of less than 200 nm, an elongation at break ranging from 300% to 600%, a Tg value less than 0 °C, and a viscosity less than 200 mPa·s. When forming a film, aliphatic polyurethane exhibits superior high-temperature resistance compared to aromatic polyurethane. Because it does not contain benzene rings, it does not suffer from high-temperature yellowing. Furthermore, its long-branched structure and Tg value less than 0 provide a more suitable balance of hardness and softness. Examples include Impaneil PU-1606, Huigu PU-2371, and Wengkaier PU-601.

[0048] Preferably, the wetting agent is a nonionic polyether modified silicone surfactant, such as at least one selected from Evonik's TEGO wet245, wet250, and Dynol 960.

[0049] Preferably, the leveling agent is one of BYK333 and BYK348.

[0050] Preferably, the defoamer is an alkynol defoamer or an organosilicone defoamer, selected from at least one of BYK-025, TEGO-842, Evonik Surfynol 104E, and Surfynol DF-110D.

[0051] Preferably, the bactericide is at least one of PROXEL GXL and Rohm and Haas LEX.

[0052] According to another aspect of this application, this application also provides a method for preparing inkjet adhesive for DTF process, the method comprising:

[0053] S101, according to the component ratio of the inkjet adhesive used in the DTF process, add thickener to the reaction vessel, and add polyester emulsion while stirring; preferably, the stirring speed is 500, and the stirring is carried out for 30 minutes until uniform.

[0054] S102, then under stirring, deionized water, wetting agent, defoamer, leveling agent and bactericide are added to the reactor in sequence; preferably, the rotation speed is 500-800 r / min, and the mixture is stirred for 120 min until homogeneous;

[0055] S103, then filtered to obtain digital inkjet adhesive. Preferably, a column filter element is used, and more preferably, a 0.45um GF filter element and a 1.0um nylon 66 filter element are selected for filtration.

[0056] Example 1

[0057] Start stirring and add 8% hydroxyethyl cellulose thickener to the reactor. While stirring, add 65% Mitsui Chemicals 6110 polyester emulsion and stir at 500 rpm for 30 minutes. Then, add 0.3% wetting agent Wet245, 0.3% defoamer 104E, 0.1% leveling agent BYK348, 0.1% bactericide GXL, and the remainder water. Stir at 800 rpm for 120 minutes. Filter the mixture sequentially using a 0.45µm GF column filter and a 1.0µm nylon 66 column filter to obtain the digital inkjet adhesive.

[0058] Example 2

[0059] Start stirring and add 8% hydroxyethyl cellulose thickener to the reactor. While stirring, add 65% Ube 6001D polyester emulsion and stir at 500 rpm for 30 minutes. Then, add 0.3% wetting agent Wet245, 0.3% defoamer 104E, 0.1% leveling agent BYK348, 0.1% bactericide GXL, and the remainder water. Stir at 800 rpm for 120 minutes. Filter the solution sequentially using a 0.45µm GF column filter and a 1.0µm nylon 66 column filter to obtain the digital inkjet adhesive.

[0060] Example 3

[0061] Start stirring and add 8% hydroxyethyl cellulose thickener to the reactor. While stirring, add 65% BASF Joncryl 631 and stir at 500 rpm for 30 minutes. Then, add the following components to the reactor in sequence: wetting agent Wet245 0.3%, defoamer 104E 0.3%, leveling agent BYK348 0.1%, bactericide GXL 0.1%, and the remainder water. Stir at 800 rpm for 120 minutes. Filter the solution sequentially using a 0.45µm GF column filter and a 1.0µm nylon 66 column filter to obtain the digital inkjet adhesive.

[0062] Example 4

[0063] Start stirring and add 8% hydroxyethyl cellulose thickener to the reactor. While stirring, add 65% BASF Joncryl 89ap and stir at 500 rpm for 30 minutes. Then, add the following components to the reactor in sequence: wetting agent Wet245 0.3%, defoamer 104E 0.3%, leveling agent BYK348 0.1%, bactericide GXL 0.1%, and the remainder water. Stir at 800 rpm for 120 minutes. Filter the solution using a 0.45µm GF column filter and a 1.0µm nylon 66 column filter sequentially to obtain the digital inkjet adhesive.

[0064] Table 1 shows the formulations and test results for Examples 1-4.

[0065]

[0066] As shown in Table 1, polyurethane emulsions have advantages over acrylic emulsions in terms of flexibility, wash fastness and adhesion, while aliphatic polyurethanes have outstanding performance in terms of yellowing resistance.

[0067] Comparative Examples 1-3 were prepared using the same configuration method as in Example 2, except that the ratios of wetting agent and polyurethane were different.

[0068] Table 2 shows the formulations and test results of Comparative Examples 1-3.

[0069]

[0070] As shown in Table 2, the adhesive formulation with the best flowability can be obtained when the ratio of wetting agent to polyurethane is between 1.7% and 2.2% (dry weight).

[0071] Comparative Example 4

[0072] Take an existing epoxy adhesive from the market and use an inkjet printer to print the adhesive and transfer the pattern onto the fabric.

[0073] Comparative Example 5

[0074] Take a commercially available silicone adhesive and use an inkjet printer to print the adhesive and transfer the pattern onto the fabric.

[0075] Comparative Example 6

[0076] Take a commercially available nitrile latex, use an inkjet printer to print the pattern onto the fabric.

[0077] Table 3 shows the test results for Example 2 and Comparative Examples 1-3.

[0078]

[0079] As shown in Table 3, epoxy resin, silicone resin, and nitrile resin are not types of adhesives used for DTF (Dystolen Powder).

[0080] Those skilled in the art should understand that the embodiments of the present invention described above are merely examples and do not limit the invention. The advantages of the present invention have been fully and effectively realized. The functional and structural principles of the present invention have been shown and explained in the embodiments; any variations or modifications can be made to the implementation of the present invention without departing from these principles.

Claims

1. An inkjet adhesive for DTF process, characterized in that, The inkjet adhesive used in the DTF process comprises the following components by weight percentage: Thickener 5%-15%; Polyester emulsion 65-85%; Wetting agent 0.1-1%; Defoamer 0.1%-0.5%; Leveling agent 0.1%-0.5%; Fungicide 0.05%-0.2% The remainder is deionized water. In addition, the inkjet adhesive used in the DTF process has a viscosity of 20-500 cP, a pH value of 7.5-8.5, a particle size distribution D50≤200nm, and a surface tension of 25-45mN / m.

2. The inkjet adhesive for DTF process according to claim 1, characterized in that, The thickener is at least one of ethylene glycol, propylene glycol, glycerin, PEG200, hydroxyethyl cellulose, and polyglycerol.

3. The inkjet adhesive for DTF process according to claim 1, characterized in that, The polyester emulsion is at least one of polyurethane emulsion, acrylate emulsion, and polyamide resin.

4. The inkjet adhesive for DTF process according to claim 3, characterized in that, The polyester emulsion is a polyurethane emulsion adhesive.

5. The inkjet adhesive for DTF process according to claim 3, characterized in that, The polyurethane is an aliphatic polyurethane resin with an average particle size of less than 200 nm, an elongation at break of 300-600%, a Tg value of less than 0 °C, and a viscosity of less than 200 MPa.

6. The inkjet adhesive for DTF process according to claim 1, characterized in that, The wetting agent is a nonionic polyether modified silicone surfactant, such as at least one selected from Evonik's TEGO wet245, wet250, and Dynol 960.

7. The inkjet adhesive for DTF process according to claim 1, characterized in that, The leveling agent is one of BYK333 and BYK348.

8. The inkjet adhesive for DTF process according to claim 1, characterized in that, The defoamer is an alkynol defoamer or an organosilicon defoamer, selected from at least one of BYK-025, TEGO-842, Evonik Surfynol 104E, and Surfynol DF-110D.

9. The inkjet adhesive for DTF process according to claim 1, characterized in that, The bactericide is at least one of PROXEL GXL and Rohm and Haas LEX.

10. A method for preparing inkjet adhesive for DTF process, characterized in that, The method includes: S101, according to the component ratio of the inkjet adhesive used in the DTF process, add thickener to the reaction vessel and add polyester emulsion while stirring; S102, then under stirring, deionized water, wetting agent, defoamer, leveling agent and bactericide are added to the reactor in sequence; S103 is then filtered to obtain digital inkjet adhesive.

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