Hot melt adhesive for transfer printing of pyrography ink-jet printing patterns and preparation method thereof

Abstract

The invention provides a hot melt adhesive for transfer printing of a pyrograph ink-jet printing pattern and a preparation method of the hot melt adhesive. The hot melt adhesive for transfer printing of the pyrograph ink-jet printing pattern comprises the following components in parts by mass: 50-70 parts of thermoplastic resin, 7-15 parts of modified titanium dioxide, 1-5 parts of a reinforcing agent, 1-5 parts of bentonite and 1-3 parts of an auxiliary agent, wherein the modified titanium dioxide is obtained by reacting titanium dioxide with a silane coupling agent and then reacting with acrylate and diisocyanate. The compatibility among the components is improved, the combination effect among the components is also improved, more active functional groups are introduced, and the material is endowed with a more stable structure, so that the comprehensive performance of the hot melt adhesive layer is improved, the appearance and washability of a printed pattern are improved, and the defects in the prior art are overcome; the method has important significance in promoting the high-end and high-quality development of the textile printing and dyeing industry.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hot melt adhesive, in particular to a hot melt adhesive for transfer printing of iron-on printing inkjet printed patterns and a preparation method thereof. BACKGROUND

[0002] With the rapid development of the textile printing and dyeing industry, consumers have higher requirements for the aesthetics, durability and environmental protection of fabric printing. The heat transfer printing technology is widely used in the printing of cotton, hemp, chemical fiber and blended fabrics, etc. due to its clear patterns, bright colors, high production efficiency, environmentally friendly process and other advantages. In the heat transfer printing process, hot melt adhesive as a key bonding material, its performance directly determines the adhesion, covering, washing resistance, flexibility and other core indicators of the printed pattern, and plays a decisive role in the quality of the final product.

[0003] Thermoplastic polyurethane (TPU) hot melt adhesive has become one of the mainstream adhesives in the field of fabric printing heat transfer due to its excellent flexibility, elastic recovery, low temperature resistance and compatibility with various fabrics. However, the existing TPU hot melt adhesive still has many performance shortcomings in practical application, which is difficult to meet the needs of high-end fabric printing: first, the covering is insufficient, especially when printing on dark fabric, the hot melt adhesive layer cannot effectively block the fabric background color, resulting in darkening of the printed pattern color and reduction of contrast, affecting the visual effect; second, the washing resistance is poor, after multiple washing or dry cleaning, the adhesive layer is prone to peeling and falling off, resulting in damage to the printed pattern; third, the bonding strength and flexibility of some TPU hot melt adhesives are difficult to balance, the adhesive layer is too hard and easy to crack, and too soft and prone to pattern displacement and wrinkling.

[0004] To solve the above problems, the industry often adds titanium dioxide to TPU hot melt adhesive to improve the covering. Titanium dioxide, as a commonly used white pigment, has high refractive index and high covering power, which can effectively block light from penetrating the adhesive layer and improve the color development effect of dark fabric printing. However, the surface of conventional titanium dioxide contains a large number of hydroxyl groups, which have strong polarity and poor compatibility with non-polar or weakly polar TPU matrix. Direct addition can easily cause agglomeration, not only failing to fully exert its covering performance, but also damaging the uniformity of the adhesive layer, resulting in a decrease in the bonding strength, flexibility and other properties of the hot melt adhesive.

[0005] The prior art such as CN118703153A-a thermoplastic polyurethane hot melt adhesive and its preparation method and application uses a coupling agent to modify titanium dioxide, improves the dispersion effect of inorganic materials in polymer resin, and realizes further improvement of hiding property and whiteness. However, the improvement effect of single coupling agent modified toner on the adhesion, strength and stability of hot melt adhesive product is still insufficient, and how to develop a hot melt adhesive with excellent hiding property, washability, bonding strength and flexibility has become a technical problem to be solved in the current heat transfer printing inkjet printing field.

[0006] In summary, there is an urgent need to develop a new technical solution to solve the problems existing in the prior art and meet the needs of the market and consumers. SUMMARY

[0007] Therefore, the present application provides a hot melt adhesive for heat transfer printing inkjet printing pattern transfer, which mainly comprises thermoplastic resin, modified titanium dioxide and reinforcing agent, not only improves the affinity between components, but also improves the combination effect between components, introduces more active functional groups, and gives the material a more stable structure, thereby improving the comprehensive performance of the hot melt adhesive layer, improving the appearance and washability of the printed pattern, solving the problems existing in the prior art, and having important significance for promoting the development of the textile printing and dyeing industry to high-end and high-quality.

[0008] One object of the present application is to provide a hot melt adhesive for heat transfer printing inkjet printing pattern transfer, which comprises the following components by mass fraction: Thermoplastic resin 50-70 parts Modified titanium dioxide 7-15 parts Reinforcing agent 1-5 parts Bentonite 1-5 parts Auxiliary agent 1-3 parts Among them, The modified titanium dioxide is obtained by reacting titanium dioxide with a silane coupling agent, and then reacting with acrylate and diisocyanate.

[0009] Further, the reinforcing agent is the product of the reaction of epoxy soybean oil and p-hydroxybenzoic acid.

[0010] Further, the thermoplastic resin is selected from one or more of ethylene-vinyl acetate copolymer resin, polyacrylic acid resin, polyurethane resin, polyethylene resin and polyamide resin.

[0011] Further, the thermoplastic resin is polyurethane resin.

[0012] Further, the auxiliary agent is selected from one or more of a toughening agent, an adhesion promoter, an antioxidant, a light stabilizer, a leveling agent and a dispersant.

[0013] Further, the silane coupling agent is an acryloyloxy silane coupling agent, and the acrylate includes a hydroxyalkyl acrylate.

[0014] Another object of the present application is to provide the preparation method of the hot melt adhesive for transferring the inkjet printed pattern of the iron-on picture, which comprises the following steps: S1, mixing and heating the titanium dioxide and the silane coupling agent to react, then adding the acrylate and the initiator to continue the reaction to obtain an intermediate product; S2, mixing and heating the intermediate product and the diisocyanate to react to obtain the modified titanium dioxide; S3, mixing and heating the epoxy soybean oil and the p-hydroxybenzoic acid to react to obtain the reinforcing agent; S4, mixing and adding the thermoplastic resin, the modified titanium dioxide, the reinforcing agent, the bentonite and the additive into an extruder to melt, extrude and granulate to obtain the hot melt adhesive for transferring the inkjet printed pattern of the iron-on picture.

[0015] Further, the mass ratio of the titanium dioxide and the acrylate is (3-5):(5-10).

[0016] Further, the mass ratio of the intermediate product and the diisocyanate is 10:(1-5).

[0017] Further, the molar ratio of the epoxy group in the epoxy soybean oil to the carboxyl group in the p-hydroxybenzoic acid is 10:(1-10).

[0018] Further, the temperature of the heating reaction is 50-130℃.

[0019] The present application has the following beneficial effects: The application discloses a hot melt adhesive for pyrography inkjet printing pattern transfer, which contains thermoplastic resin, modified titanium white powder and reinforcing agent and the like. DETAILED DESCRIPTION

[0020] In order to more clearly illustrate the technical solutions of the present application, the following examples are listed. The raw materials, reactions and post-treatment methods appearing in the examples are all common raw materials on the market and technical means well known to those skilled in the art, unless otherwise stated.

[0021] The words "preferred", "preferably", "more preferred" and the like in the present application refer to the embodiments of the present application which can provide certain beneficial effects in certain cases. However, other embodiments can also be preferred in the same or other cases. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not usable, nor is it intended to exclude other embodiments from the scope of the present application.

[0022] It should be understood that, except in any operating examples, or otherwise indicated, all numbers appearing in the specification and claims, such as those expressing values of quantities of ingredients used in the composition, are to be understood as modified in all instances by the term "about". Accordingly, unless indicated otherwise, the numerical parameters set forth in the following specification and attached claims are approximations that can vary depending on the desired properties sought to be obtained in accordance with the present application.

[0023] The thermoplastic resin in the embodiments of the present application is thermoplastic polyurethane resin, BASF 1095A.

[0024] The particle size of the titanium white powder in the embodiments of the present application is less than or equal to 600 nm.

[0025] The auxiliary in the embodiment of the application is an antioxidant 1010 and a dispersant magnesium stearate with a mass ratio of 1:1.

[0026] The epoxy value of the epoxy soybean oil in the embodiment of the application is 6%.

[0027] The "parts" in the embodiment of the application all refer to mass parts.

[0028] Embodiment 1 A hot melt adhesive for heat transfer printing of inkjet printed patterns, the hot melt adhesive for heat transfer printing of inkjet printed patterns comprising ingredients in mass parts as follows: Thermoplastic resin 55 parts Modified titanium white 8 parts Reinforcing agent 3 parts Bentonite 3 parts Auxiliary 1 part The preparation method of the hot melt adhesive for heat transfer printing of inkjet printed patterns comprises the following steps: S1, using a mixture of ethanol and water with a mass ratio of 9:1 as a solvent, adding titanium white and KH-570 with a mass ratio of 5:1, reacting at 80 DEG C for 12 hours, and then washing and drying to obtain double bond modified titanium white; Using N,N-dimethylformamide as a solvent, mixing the double bond modified titanium white, butyl acrylate, hydroxyethyl methacrylate and azobisisobutyronitrile with a mass ratio of 3:4:3:0.1, stirring and reacting at 85 DEG C for 6 hours, and then filtering, washing and drying to obtain an intermediate product; S2, using N,N-dimethylformamide as a solvent, mixing the intermediate product and hexamethylene diisocyanate with a mass ratio of 10:2.5, ultrasonic reacting at 60 DEG C for 2 hours, and then filtering, washing and drying to obtain modified titanium white; S3, using N,N-dimethylformamide as a solvent, mixing epoxy soybean oil and p-hydroxybenzoic acid (the molar ratio of epoxy groups in epoxy soybean oil to carboxyl groups in p-hydroxybenzoic acid is 10:3), and then adding 5 wt% of triphenylphosphine in epoxy soybean oil, stirring and reacting at 130 DEG C for 8 hours, and then removing the solvent by reduced pressure distillation to obtain a reinforcing agent; S4, mixing the thermoplastic resin, modified titanium white, reinforcing agent, bentonite and auxiliary in the above mass parts into an extruder, melt extruding and granulating at 140-150 DEG C to obtain the hot melt adhesive for heat transfer printing of inkjet printed patterns.

[0029] Embodiment 2 A hot melt adhesive for heat transfer printing of inkjet printed patterns, the hot melt adhesive for heat transfer printing of inkjet printed patterns comprising ingredients in mass parts as follows: Thermoplastic resin 60 parts Modified titanium white 10 parts Reinforcing agent 3.5 parts Bentonite 3.5 parts Auxiliary agent 1.2 parts; The preparation method of the hot melt adhesive for transferring the inkjet printed pattern of iron-on picture comprises the following steps: S1, adding titanium dioxide and KH-570 with a mass ratio of 5:1 as solvents in an ethanol and water mixture with a mass ratio of 9:1, reacting at 80°C for 12 hours, and then washing and drying to obtain double bond modified titanium dioxide; Mixing the double bond modified titanium dioxide, butyl acrylate, hydroxyethyl methacrylate and azobisisobutyronitrile with a mass ratio of 3:4:3:0.1 as solvents in N,N-dimethylformamide, stirring and reacting at 85°C for 6 hours, and then filtering, washing and drying to obtain an intermediate product; S2, mixing the intermediate product and hexamethylene diisocyanate with a mass ratio of 10:2.5 as solvents, ultrasonic reacting at 60°C for 2 hours, and then filtering, washing and drying to obtain modified titanium dioxide; S3, mixing epoxy soybean oil and p-hydroxybenzoic acid as solvents (the molar ratio of epoxy groups in epoxy soybean oil to carboxyl groups in p-hydroxybenzoic acid is 10:3), then adding 5 wt% of triphenylphosphine in epoxy soybean oil, stirring and reacting at 130°C for 8 hours, and then removing the solvent by reduced pressure distillation to obtain a reinforcing agent; S4, mixing the thermoplastic resin, modified titanium dioxide, reinforcing agent, bentonite and auxiliary agent according to the above mass fractions into an extruder, melt extruding and granulating at 140-150°C to obtain the hot melt adhesive for transferring the inkjet printed pattern of iron-on picture.

[0030] Example 3 A hot melt adhesive for transferring the inkjet printed pattern of iron-on picture, the hot melt adhesive for transferring the inkjet printed pattern of iron-on picture comprises ingredients with mass fractions as follows: Thermoplastic resin 70 parts Modified titanium dioxide 12 parts Reinforcing agent 4 parts Bentonite 4 parts Auxiliary agent 1.5 parts; The preparation method of the hot melt adhesive for transferring the inkjet printed pattern of iron-on picture comprises the following steps: S1, adding titanium dioxide and KH-570 with a mass ratio of 5:1 as solvents in an ethanol and water mixture with a mass ratio of 9:1, reacting at 80°C for 12 hours, and then washing and drying to obtain double bond modified titanium dioxide; Mixing the double bond modified titanium dioxide, butyl acrylate, hydroxyethyl methacrylate and azobisisobutyronitrile with a mass ratio of 3:4:3:0.1 as solvents in N,N-dimethylformamide, stirring and reacting at 85°C for 6 hours, and then filtering, washing and drying to obtain an intermediate product; S2, the intermediate product and hexamethylene diisocyanate were mixed in a mass ratio of 10:2.5 with N,N-dimethylformamide as the solvent, and ultrasonic reaction was carried out at 60°C for 2 h. After filtration, washing and drying, the modified titanium white powder was obtained; S3, the epoxy soybean oil and p-hydroxybenzoic acid were mixed (the molar ratio of epoxy groups in the epoxy soybean oil to carboxyl groups in the p-hydroxybenzoic acid was 10:3) with N,N-dimethylformamide as the solvent, and then 5 wt% of triphenylphosphine of the epoxy soybean oil was added. Stirring reaction was carried out at 130°C for 8 h. The solvent was removed by distillation under reduced pressure to obtain the reinforcing agent. S4, the thermoplastic resin, the modified titanium white powder, the reinforcing agent, the bentonite and the auxiliary agent were mixed and added into the extruder according to the above mass fractions. Melt extrusion granulation was carried out at 140-150°C to obtain the hot melt adhesive for heat transfer printing of inkjet printed patterns.

[0031] Comparative Example 1 A hot melt adhesive for heat transfer printing of inkjet printed patterns, which is different from Example 1 in that step S2 is deleted, and the intermediate product is used as the modified titanium white powder, and the other components and preparation methods are the same as those of Example 1.

[0032] Comparative Example 2 A hot melt adhesive for heat transfer printing of inkjet printed patterns, which is different from Example 1 in that step S3 is deleted, and the epoxy soybean oil is used as the reinforcing agent, and the other components and preparation methods are the same as those of Example 1.

[0033] Test Example The hot melt adhesives for heat transfer printing of inkjet printed patterns prepared in the examples and comparative examples were tested for performance.

[0034] Test Method: Mechanical properties: The hot melt adhesive sample was pressed into a 2 mm thick sheet using a flat vulcanizing machine, and then the sample was punched according to GB / T1040.1-2022 (5A type sample), and the tensile properties were tested.

[0035] Peeling strength: The hot melt adhesive sample was pressed into a 1 mm thick sheet using a flat vulcanizing machine, and then the sample was punched into a 10 cm×2.5 cm (length×width) adhesive strip. The adhesive strip was placed between two cotton strips with a size of 150 mm×25 mm×2 mm (length×width×height), and heat treated at 150°C for 2 min. The excess adhesive around the sample was removed, and the sample was prepared. After cooling at room temperature for 24 h, the peeling strength was measured according to GB / T 2791-1995.

[0036] Heat transfer effect: The heat transfer film was prepared according to the method of Example 1 in CN111619257A - A heat transfer film and its production process. From bottom to top, the layers are: 8 μm anti-stick layer, 20 μm base layer, 15 μm release layer, 10 μm polyurethane layer, and 12 μm ink layer. Then, a heat transfer film with a thickness of 1 g / m³ was applied. 2 Hot melt adhesive prepared according to the embodiments or comparative examples of the present invention was applied to the surface of the ink layer to obtain a heat transfer film. The heat transfer film was baked at 80°C for 25 seconds, followed by baking at 130°C for 2 minutes. After baking, the pattern was heat-pressed onto the surface of cotton fabric using a heat transfer machine at a temperature of 150°C, a time of 10 seconds, and a pressure of 5 kg. The color fastness to washing and rubbing (dry) was tested according to GB / T 3921-2008 and GB / T 3920-2008.

[0037] The test results are shown in Table 1.

[0038] Table 1 Performance Test Results As shown in Table 1, the hot melt adhesive prepared in the embodiments of the present invention for heat transfer inkjet printing patterns exhibits strong mechanical properties, high elongation at break, and high peel strength. Furthermore, its overall performance is excellent after application to heat transfer film, ensuring the firmness and stability of the heat transfer pattern. Comparative Example 1, by replacing modified titanium dioxide and not introducing polyurethane segments, reduced the degree of cross-linking and bonding between components, thus affecting the strength of the hot melt adhesive and its adhesion and durability after transfer. Comparative Example 2, by replacing the reinforcing agent with epoxidized soybean oil, lacked benzene rings, phenolic hydroxyl groups, etc., which also significantly affected the strength and stability of the hot melt adhesive. In summary, the present invention overcomes the defects existing in the prior art and has good application prospects.

[0039] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0040] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A hot-melt glue for use in the transfer of a hot-stencil inkjet printed pattern, characterized in that, The hot melt adhesive for transferring the inkjet printed pattern of hot stamping comprises ingredients in mass fractions as follows: thermoplastic resin 50-70 parts modified titanium white 7-15 parts reinforcing agent 1-5 parts bentonite 1-5 parts auxiliary agent 1-3 parts wherein, the modified titanium white is obtained by reacting titanium white with silane coupling agent, and then reacting with acrylate and diisocyanate.

2. The hot-melt glue for transfer printing of iron-on inkjet printed patterns according to claim 1, wherein the reinforcing agent is the product of the reaction of epoxy soybean oil and p-hydroxy benzoic acid.

3. The hot-melt glue for the transfer of the hot press picture inkjet printed pattern according to claim 1, characterized in that, the thermoplastic resin is selected from one or more of ethylene-vinyl acetate copolymer resin, polyacrylic acid resin, polyurethane resin, polyethylene resin and polyamide resin.

4. The hot-melt glue for transfer printing of iron-on inkjet printed patterns according to claim 3, wherein the thermoplastic resin is polyurethane resin.

5. The hot-melt glue for transfer printing of iron-on inkjet printed patterns according to claim 1, wherein the auxiliary agent is selected from one or more of toughening agent, tackifier, antioxidant, light stabilizer, leveling agent and dispersant.

6. The hot-melt glue for transfer printing of iron-on inkjet printed patterns according to claim 1, wherein the silane coupling agent is acryloyloxy silane coupling agent, and the acrylate includes hydroxyalkyl acrylate.

7. The process for the preparation of hot-melt glue for the transfer of inkjet printed patterns for hot-painting according to any one of claims 1 to 6, characterized in that, The preparation method of the hot melt adhesive for transferring the inkjet printed pattern of hot stamping comprises the following steps: S1, mixing and heating titanium white and silane coupling agent to react, then adding acrylate and initiator to continue the reaction to obtain an intermediate product; S2, mixing and heating the intermediate product and diisocyanate to obtain modified titanium white; S3, mixing and heating epoxy soybean oil and p-hydroxy benzoic acid to obtain a reinforcing agent; S4, mixing and adding thermoplastic resin, modified titanium white, reinforcing agent, bentonite and auxiliary agent into an extruder, melt extruding and granulating to obtain the hot melt adhesive for transferring the inkjet printed pattern of hot stamping.

8. The method of claim 7, wherein the hot-melt adhesive is prepared by mixing a thermoplastic resin, a tackifier, a plasticizer, and a filler. The mass ratio of titanium white to acrylate is (3-5):(5-10).

9. The method of claim 7, wherein the hot-melt adhesive is prepared by mixing a thermoplastic resin, a tackifier, a plasticizer, and a filler. The mass ratio of the intermediate product to diisocyanate is 10:(1-5).

10. The method of claim 7, wherein the hot-melt adhesive is prepared by mixing a thermoplastic resin, a tackifier, a plasticizer, and a filler. The molar ratio of epoxy groups in epoxy soybean oil to carboxyl groups in p-hydroxy benzoic acid is 10:(1-10).

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