A Tencel digital printing process

Abstract

This invention discloses a Tencel digital printing process that uses light irradiation for curing and uses a coating ink. This shortens the process flow and significantly reduces water, energy, and waste discharge, promising promising industrial applications. The preparation method begins by pre-treating the Tencel fabric surface to functionalize it. This allows it to chemically bond with the active substances in the ink, including polyurethane acrylate oligomers and free radical-reactive diluents, forming a sandwich structure that embeds the pigment between the fabric and the polymer film. This significantly improves the pigment's adhesion stability and enhances color fastness.

Description

Technical Field

[0001] The invention belongs to the technical field of fabric digital printing, and particularly relates to a Tencel digital printing process. Background Art

[0002] Tencel is a purely natural, regenerated fiber developed by the British company Acordis using 100% natural wood pulp extracted from trees. It has been dubbed the "fiber dream of the 21st century." It is softer than silk, more absorbent than cotton, lightweight, and easy to wash and dry. However, Tencel fiber has a very thin cortex structure, nearly a full core structure, allowing water molecules to be rapidly absorbed by the pores between the nanofibrils. Consequently, ink droplets bleed significantly when using reactive dye inkjet printing, affecting the clarity of the printed outline. While surface modification of Tencel fabrics before reactive dye inkjet printing can control the distribution of ink droplets on the fabric surface and improve the printing effect, the process requires a series of post-processing steps, including steaming, washing, and soaping, which are energy-intensive, water-intensive, and pollutant-intensive. Therefore, improving the inkjet printing process for Tencel fabrics to improve printing efficiency, improve printing quality, and reduce energy consumption is crucial.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The present invention provides a Tencel digital printing process, which not only has a short process flow, high production efficiency, low energy consumption and low pollution, but also has high print clarity, high apparent color depth and high color fastness.

[0005] The present invention is achieved through the following technical solutions:

[0006] A Tencel digital printing process comprises the following steps:

[0007] (1) dissolving an acryloyl chloride compound in a solvent to obtain a pretreatment solution;

[0008] (2) applying the pretreatment liquid to the surface of the Tencel fabric;

[0009] (3) drying;

[0010] (4) preparing a pigment printing ink, wherein the pigment printing ink comprises a polyurethane acrylate oligomer, a free radical active diluent, a photoinitiator, and a pigment;

[0011] (5) digital inkjet printing to obtain digital inkjet printed fabric;

[0012] (6) Photocuring.

[0013] In some embodiments of the present invention, the acryloyl chloride compound includes at least one of methacryloyl chloride, 3-methylcrotonoyl chloride, or crotonoyl chloride.

[0014] In some embodiments of the present invention, the boiling point of the solvent is lower than 120° C.; preferably, the solvent is acetonitrile, dichloromethane, ethyl acetate or acetone.

[0015] In some embodiments of the present invention, the mass percentage of the acryloyl chloride compound in the pretreatment liquid is 2% to 8%.

[0016] In some embodiments of the present invention, the fabric pretreatment is performed by dipping, padding, spraying or coating.

[0017] In some embodiments of the present invention, the drying temperature is 90-150° C. and the drying time is 3-6 hours.

[0018] In some embodiments of the present invention, the pigment printing ink comprises, calculated by mass percentage, 30% to 50% of polyurethane acrylate oligomer, 47% to 68% of free radical active diluent, 0.5% to 1% of photoinitiator, and 1% to 2% of pigment.

[0019] In some embodiments of the present invention, the polyurethane acrylate oligomer includes a polysiloxane segment; further, the polyurethane acrylate oligomer is prepared as follows: a double-terminal hydroxyl silicone oil is prepolymerized with a difunctional isocyanate, 1,4-diamino-2-butene is added for chain extension, and finally hydroxyethyl methacrylate is added for end-capping to obtain the polyurethane acrylate oligomer.

[0020] In some embodiments of the present invention, the polyurethane acrylate oligomer includes a polysiloxane segment and a polyether segment; further, the polyurethane acrylate oligomer is prepared as follows: a double-terminal hydroxy silicone oil, a polyether polyol and a difunctional isocyanate are prepolymerized to obtain a silicone oil prepolymer and a polyether polyol prepolymer, 1,4-diamino-2-butene is added to the silicone oil prepolymer to carry out a chain extension reaction, and then a polyethylene glycol prepolymer is added to continue the reaction, and finally hydroxyethyl methacrylate is added for end-capping to obtain the polyurethane acrylate oligomer.

[0021] In some embodiments of the present invention, the difunctional isocyanate is at least one of isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, or hexamethylene diisocyanate.

[0022] In some embodiments of the present invention, the viscosity of the polyurethane acrylate oligomer is ≤2.5 Pa·s.

[0023] In some embodiments of the present invention, the pigment is a pigment surface-modified with a vinyl silane coupling agent; preferably, the vinyl silane coupling agent is at least one of vinyl trimethoxy silane, vinyl triethoxy silane, and γ-methacryloxypropyl trimethoxy silane.

[0024] In some embodiments of the present invention, the method for preparing a vinyl silane coupling agent surface-modified pigment is as follows: dispersing the pigment in an aqueous solution of the vinyl silane coupling agent, adding an acid or base and stirring the reaction, separating the solid and liquid, washing, and drying to obtain the vinyl silane coupling agent surface-modified pigment.

[0025] In some embodiments of the present invention, the free radical active diluent is at least one of ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, isooctyl (meth)acrylate, hydroxyethyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl acrylate, and hydroxypropyl (meth)acrylate.

[0026] In some embodiments of the present invention, the photoinitiator is at least one of an aromatic ketone initiator, an α-hydroxyalkyl phenone initiator, a thioxanthone derivative, and an organic metallocene initiator; preferably, the photoinitiator is one of camphorquinone, benzoin dimethyl ether, α-hydroxycyclohexyl benzophenone, and isopropyl thioxanthone.

[0027] In some embodiments of the present invention, light curing refers to radiation curing of digital inkjet printed fabrics using light with a wavelength of 200 to 480 nm.

[0028] The present invention has the following advantages and beneficial effects:

[0029] (1) The present invention provides a Tencel digital printing process, which uses light irradiation for curing and selects coating ink, shortening the process flow and greatly reducing water and energy consumption and pollution discharge, and has good industrialization prospects.

[0030] (2) The present invention provides a Tencel digital printing process. First, the Tencel fabric surface is pretreated to functionalize the surface, enabling chemical bonding with active substances in the ink, including polyurethane acrylate oligomers and free radical reactive diluents, to form a sandwich structure that embeds the pigment between the fabric and the polymer film, greatly improving the adhesion stability of the pigment and enhancing color fastness. Furthermore, the pigment is surface-modified using the same functional groups, allowing the pigment to participate in the chemical bonding, thereby improving the compatibility between the pigment and the polymer film and further improving the color fastness of the print.

[0031] (3) The polyurethane acrylate oligomer contained in the digital inkjet printing ink provided by the present invention contains silicone oil segments and / or polyether segments, and has good softness. By adjusting the relative content of the soft and hard segments of the polyurethane acrylate oligomer in the ink, as well as its content ratio with the free radical active diluent, the viscosity of the ink, the elasticity and feel of the printed pattern after curing can be regulated. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the infrared spectrum of sample 3 polyurethane acrylate oligomer.

[0033] Figure 2 The Tencel fabric printing picture of Example 7. DETAILED DESCRIPTION

[0034] In the present invention, unless otherwise specified, the raw materials used are commercially available products familiar to those skilled in the art. The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0035] The polyurethane acrylate oligomer used in some embodiments of the present invention is prepared by the following method: weighing a difunctional isocyanate and adding it into a reactor, turning on a nitrogen protection device, heating to 80° C. and then starting to dropwise add an alcohol hydroxy silicone oil solution, and continuing to keep the temperature for reaction for 2 hours after the addition is complete to obtain a silicone oil prepolymer; in parallel, a polyether prepolymer is prepared by the same method; adding a chain extender 1,4-diamino-2-butene solution dropwise to the reactor containing the silicone oil prepolymer, and continuing to keep the temperature for reaction for 2 hours after the addition is complete, and then optionally adding a polyether prepolymer, and stirring at the temperature for 2 hours; finally, adding a capping agent hydroxyethyl methacrylate (HEA), stirring at the temperature for 4 hours, then removing from the pot, and evaporating the solvent to obtain a polyurethane acrylate oligomer.

[0036] For example, polyurethane acrylate oligomer was prepared according to the above method, and the process parameters and viscosity are shown in Table 1.

[0037] Table 1

[0038]

[0039] a The mass of the difunctional isocyanate is the total amount used to prepare the polyurethane acrylate oligomer sample, and is allocated according to the molar ratio of alcohol hydroxy silicone oil and polyether polyol when preparing the silicone oil prepolymer and the polyether prepolymer respectively.

[0040] The infrared spectrum of sample 3 is shown in the attached manual. Figure 2 As shown in the figure, 1100cm -1 and 1080cm -1 The characteristic absorption peaks of Si-O and Si-C appeared at 1600-1680 cm -1 There are two characteristic absorption peaks of C=C, corresponding to C=C in different chemical environments, 1720cm -1 The characteristic absorption peak of C=O appeared, indicating that the polyurethane acrylate oligomer containing silicone oil segment was successfully synthesized.

[0041] It is worth noting that the types of polyether polyols include polytetramethylene glycol, polybutylene glycol, etc., and are not limited to polypropylene glycol and polyethylene glycol. The number average molecular weight of the polyether polyol includes any value between 200 and 2000 g / mol, and is not limited to 400 g / mol or 1000 g / mol. Those skilled in the art can select the type and molecular weight of the polyether polyol according to the target feel, elasticity and hydrophilicity of the printing, as well as the viscosity of the ink. It is also feasible to input two or more polyether polyols with different molecular weights or types. The polyether polyols used in Table 1 above are only exemplary and not intended to limit the scope of protection of the present invention. In addition, the number average molecular weight of the alcohol hydroxy silicone oil is preferably 800 to 1500 g / mol. The alcohol hydroxy silicone oil within this range is not only easy to obtain raw materials but also the prepared polyurethane acrylate oligomer meets the viscosity requirements. In addition, hydroxyethyl acrylate can also be replaced with hydroxypropyl acrylate or hydroxybutyl acrylate.

[0042] Alcoholic hydroxy silicone oil was purchased from Anhui Aiyota Silicone Oil Co., Ltd.

[0043] In some embodiments of the present invention, the vinyl silane coupling agent surface-modified pigment used is prepared by the following method: preparing an aqueous solution with a pH of 2 to 6 or a pH of 8 to 12, adding a vinyl silane coupling agent and stirring to dissolve, adding pigment powder and uniformly dispersing it by stirring and / or ultrasonication, heating to 40 to 80° C. and uniformly stirring for 1 hour, then centrifuging to separate the solid, washing the solid with water multiple times, and drying to obtain the vinyl silane coupling agent surface-modified pigment.

[0044] The pigment is selected according to the color of the printed pattern, including but not limited to titanium dioxide, iron oxide red, iron oxide yellow, and iron oxide blue.

[0045] For example, vinyl silane coupling agent surface-modified red iron oxide was prepared according to the above method. The vinyl silane coupling agent was γ-methacryloxypropyltrimethoxysilane, the pH of the aqueous solution was 4, the feeding ratio of the aqueous solution, γ-methacryloxypropyltrimethoxysilane, and red iron oxide was 100 mL: 0.1 g: 1 g, and the reaction temperature was 60°C.

[0046] Titanium dioxide, iron oxide red, iron oxide yellow, and iron oxide blue were purchased from Tianjin Jifa Pigment Co., Ltd.

[0047] Some embodiments are provided below to illustrate the technical solutions of the present invention.

[0048] Example 1

[0049] A Tencel digital printing process comprises the following steps:

[0050] Tencel satin fabric (20 tex × 28 tex, 132 strands / 10 cm × 62 strands / 10 cm) was purchased from Hangzhou Runyan Textile Technology Co., Ltd.

[0051] (1) Preparing a pretreatment solution: dissolving methacryloyl chloride in dichloromethane to obtain a pretreatment solution having a methacryloyl chloride content of 2 wt %;

[0052] (2) Fabric pretreatment: The pretreatment liquid was applied to the surface of the Tencel fabric by spraying and left to stand for 3 hours. The amount of pretreatment liquid applied was 200 mL / m 2 ;

[0053] (3) Drying: Place the Tencel plain weave fabric in a 90°C forced air oven and dry it for 1 hour.

[0054] (4) Preparation of pigment printing ink: polyurethane acrylate oligomer, free radical active diluent, and pigment were pre-dispersed by shearing at 5000 rpm for 15 min in a high-speed shearing machine; then transferred to a ball mill and further ground and dispersed using 0.1 mm agate beads until the solid particle size was less than 800 nm. Finally, a photoinitiator was added and ultrasonically dispersed for 10 min in the dark to prepare the pigment printing ink.

[0055] Among them, the polyurethane acrylate oligomer is sample 3 in Table 1, the free radical active diluent is a mixture of butyl acrylate, hydroxyethyl methacrylate, and isobornyl acrylate in a mass ratio of 1:1:2; the photoinitiator is benzoin dimethyl ether; the pigment is purchased iron oxide red; the percentage content of each component is: 30% sample 3, 68% free radical active diluent, 0.5% benzoin dimethyl ether, and 1.5% iron oxide red.

[0056] (5) Digital inkjet printing: Add pigment printing ink to the digital printing equipment, and use digital control to print on the fabric surface as needed to obtain the desired pattern (needle inner diameter 0.15mm (30G), air pressure 80kPa, moving speed 10mm / s).

[0057] (6) Photocuring: Place the printed fabric in a nitrogen atmosphere and cure it with ultraviolet light using a 250W, 365nm main wavelength high-pressure mercury lamp for 10 minutes.

[0058] Example 2

[0059] A Tencel digital printing process comprises the following steps:

[0060] Tencel satin fabric (20 tex × 28 tex, 132 strands / 10 cm × 62 strands / 10 cm) was purchased from Hangzhou Runyan Textile Technology Co., Ltd.

[0061] (1) preparing a pretreatment solution: dissolving crotonyl chloride in acetonitrile to obtain a pretreatment solution having a crotonyl chloride content of 5 wt %;

[0062] (2) Fabric pretreatment: The pretreatment solution was applied to the surface of the Tencel fabric through multiple coatings and allowed to stand for 3 h. The amount of pretreatment solution applied was 80 mL / m 2 ;

[0063] (3) Drying: Place the Tencel plain weave fabric in a 130°C forced air oven and dry it for 3 hours.

[0064] (4) Preparation of pigment printing ink: polyurethane acrylate oligomer, free radical active diluent, and pigment were pre-dispersed by shearing at 5000 rpm for 15 min in a high-speed shearing machine; then transferred to a ball mill and further ground and dispersed using 0.1 mm agate beads until the solid particle size was less than 800 nm. Finally, a photoinitiator was added and ultrasonically dispersed for 10 min in the dark to prepare the pigment printing ink.

[0065] The polyurethane acrylate oligomer is sample 1 in Table 1, and the free radical active diluent is a mixture of ethyl acrylate, dicyclopentenyl acrylate, and hydroxypropyl methacrylate in a mass ratio of 1:1:2;

[0066] The photoinitiator is isopropylthioxanthone; the pigment is purchased red iron oxide; the percentage content of each component is: 40% sample 1, 58% free radical active diluent, 1% isopropylthioxanthone, and 1% red iron oxide.

[0067] Steps (5) to (6) are the same as in Example 1.

[0068] Example 3

[0069] A Tencel digital printing process comprises the following steps:

[0070] (1) preparing a pretreatment solution: dissolving 3-methyl crotonyl chloride in ethyl acetate to obtain a pretreatment solution having a 3-methyl crotonyl chloride content of 8 wt %;

[0071] (2) Fabric pretreatment: The pretreatment solution was applied to the surface of the Tencel fabric by two dipping and two rolling, with a liquid rate of 60%, and allowed to stand for 3 hours;

[0072] (3) Drying: Place the Tencel plain fabric in a 90°C forced air oven and dry for 3 h.

[0073] (4) Preparation of pigment printing ink: polyurethane acrylate oligomer, free radical active diluent, and pigment were pre-dispersed by shearing at 5000 rpm for 15 min in a high-speed shearing machine; then transferred to a ball mill and further ground and dispersed using 0.1 mm agate beads until the solid particle size was less than 800 nm. Finally, a photoinitiator was added and ultrasonically dispersed for 10 min in the dark to prepare the pigment printing ink.

[0074] The polyurethane acrylate oligomer is sample 2 in Table 1, and the free radical active diluent is a mixture of isooctyl methacrylate and hydroxyethyl methacrylate in a mass ratio of 3:2.

[0075] The photoinitiator is camphorquinone; the pigment is purchased titanium dioxide; the percentage content of each component is: 50% sample 2, 47% free radical active diluent, 1% camphorquinone, and 2% titanium dioxide.

[0076] Step (5) is the same as in Example 1.

[0077] (6) Photocuring: Place the printed fabric in a nitrogen atmosphere and irradiate it with a 50W, 465nm main wavelength blue light LED for 10 minutes for curing.

[0078] Example 4

[0079] The difference from Example 1 is that red iron oxide surface-modified with a vinyl silane coupling agent is used instead of red iron oxide as the pigment.

[0080] Example 5

[0081] The difference from Example 1 is that Sample 1 in Table 1 is used instead of Sample 3 as the polyurethane acrylate oligomer.

[0082] Example 6

[0083] The difference from Example 1 is that Sample 2 in Table 1 is used instead of Sample 3 as the polyurethane acrylate oligomer.

[0084] Example 7

[0085] The difference from Example 1 is that iron oxide blue surface-modified with a vinyl silane coupling agent is used as the pigment instead of iron oxide red.

[0086] The printing pictures of Tencel fabric in this embodiment are shown in the attached manual. Figure 2As shown in the figure, it can be seen that the printed pattern has clear outlines and deep apparent color.

[0087] Comparative Example 1

[0088] The difference from Example 1 is that the Tencel fabric is not pretreated, that is, the Tencel fabric is directly subjected to step (5) digital inkjet printing using the ink of step (4).

[0089] Comparative Example 2

[0090] The difference from Example 1 is that no polyurethane acrylate oligomer is added to the pigment printing ink in step (4), that is, the percentage content of each component of the pigment printing ink is: 98% free radical active diluent, 0.5% benzoin dimethyl ether, and 1.5% iron oxide red.

[0091] Comparative Example 3

[0092] The difference from Example 2 is that the pigment printing ink is prepared by using vinyl silicone oil with Mn=1000 g / mol instead of polyurethane acrylate oligomer.

[0093] Vinyl silicone oil was purchased from Anhui Aiyota Silicone Oil Co., Ltd.

[0094] Comparative Example 4

[0095] The difference from Example 3 is that N-methyldiethanolamine is used instead of 1,4-diamino-2-butene as the chain extender to prepare the polyurethane acrylate oligomer. The preparation method is the same as that of Sample 2 in Table 1.

[0096] The mass ratio of polypropylene glycol (Mn=1000 g / mol), 4,4'-dicyclohexylmethane diisocyanate, N-methyldiethanolamine, and hydroxyethyl methacrylate is 10:5.78:0.6:1.82.

[0097] The pigment printing inks prepared in the examples and comparative examples and the printed Tencel fabrics were tested.

[0098] Test Example 1: Viscosity of Pigment Printing Ink

[0099] Obtained by testing with a rotational viscometer.

[0100] Test Example 2: Paint film mechanical properties test

[0101] The pigment printing ink was poured onto a tetrafluoroethylene mold and then cured under the same light curing conditions to obtain a paint film with a thickness of 0.1 to 0.2 mm. The tensile strength and elongation at break of the film were tested using a universal materials testing machine Instron 3367 in accordance with GB / T 1040.3-2006 "Determination of tensile properties of plastic films" at a tensile speed of 10 mm / min.

[0102] Test Example 3: Paint film flexibility test

[0103] The flexibility of the paint film was tested using a paint film flexibility tester in accordance with GB / T 1731-2020 "Determination of flexibility of paint films and putty films".

[0104] Test Example 4: Apparent Color Depth K / S Value Test

[0105] The apparent color depth K / S value was measured using a Datacolor 650 colorimeter with a D65 light source and a 10° viewing angle. The K / S value at the maximum absorption wavelength of the printed pattern was measured four times for each sample at different locations, and the average value was taken.

[0106] Test Example 5 Color Fastness Test

[0107] Color fastness to rubbing is determined in accordance with GB / T 3920-2008 Textiles—Tests for color fastness—Color fastness to rubbing.

[0108] The color fastness to yellowing from light is determined in accordance with GB / T 30669-2014 “Textiles—Tests for Color Fastness—Color Fastness to Yellowing from Light”, and the irradiation time is 6 hours.

[0109] The test results are shown in Tables 2 and 3.

[0110] Table 2

[0111]

[0112]

[0113] As can be seen from Table 3, the viscosity of the pigment printing ink provided by the present invention is low after heating, which meets the application requirements of digital inkjet printing, and the paint film has good tensile strength and elongation at break, so it has good flexibility. When applied to print patterns on fabric surfaces, it has good softness and elasticity, which is conducive to improving durability. From the paint film properties of Examples 1 to 6, it can be seen that the paint film properties can be regulated by regulating the type and ratio of the chain segments in the polyurethane acrylate oligomer in the ink and the ratio of each component in the ink. In addition, from Examples 1 and 3, it can be seen that the ink formula provided by the present invention can be applied to UV curing and blue light curing, and the effect of the cured paint film is not much different. The corresponding photoinitiator can be selected according to the process requirements. Examples 1 and 4 show that surface modification of the pigment improves the tensile strength of the paint film. Example 1 and Comparative Example 2 show that omitting the addition of a polyurethane acrylate oligomer reduces both the tensile strength and elongation at break of the paint film. Example 2 and Comparative Example 3 show that replacing the polyurethane acrylate oligomer with vinyl silicone oil significantly reduces the elongation at break of the paint film. This is because the polyurethane acrylate oligomer contains substituted urea groups (R2N-(C=O)-NR2), which act as hard segments and aggregate to form ordered microdomains. These domains provide physical crosslinking points, enhancing the mechanical strength of the material. The silicone oil segments, acting as soft segments, form an amorphous continuous phase, ensuring the material's flexibility, thereby simultaneously improving the strength and elongation at break of the paint film. Compared to Comparative Example 4, Example 3 uses N-methyldiethanolamine instead of 1,4-diamino-2-butene as the chain extender, reducing the number of vinyl reactive groups and, therefore, the tensile strength.

[0114] Table 3

[0115]

[0116]

[0117] As shown in Table 3, the present invention uses coating inks to print Tencel fabrics, resulting in prints with excellent apparent color depth and color fastness. Specifically, Example 4 exhibits higher color fastness than Example 1, indicating that the participation of surface-modified pigments in the photocuring process is beneficial for improving pigment color fastness. Compared to Comparative Example 4, Example 3 shows significantly improved color fastness to light yellowing in the polyurethane acrylate oligomer prepared using 1,4-diamino-2-butene as a chain extender, compared to N-methyldiethanolamine. This is due to the fact that amino groups are susceptible to yellowing under high temperatures or ultraviolet light. Compared to Example 1, Comparative Example 1 exhibits inferior apparent color depth and color fastness due to the lack of surface treatment on the fabric, indicating that the participation of the fabric in the curing process is beneficial for improving the color fastness of the print.

[0118] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A Tencel digital printing process, characterized in that: The following steps are involved: (1) dissolving an acryloyl chloride compound in a solvent to obtain a pretreatment solution; (2) applying the pretreatment liquid to the surface of the Tencel fabric; (3) Drying; (4) preparing a pigment printing ink, wherein the pigment printing ink comprises a polyurethane acrylate oligomer, a free radical active diluent, a photoinitiator, and a pigment; (5) Digital inkjet printing to obtain digital inkjet printed fabrics; (6) Light curing; The polyurethane acrylate oligomer includes a polysiloxane segment and is prepared by the following method: a difunctional hydroxy silicone oil is prepolymerized with a difunctional isocyanate, 1,4-diamino-2-butene is added for chain extension, and hydroxyethyl methacrylate or hydroxypropyl methacrylate is added for end-capping to obtain the polyurethane acrylate oligomer; And / or, the polyurethane acrylate oligomer includes a polysiloxane segment and a polyether segment, and is prepared by the following method: a double-terminal hydroxy silicone oil, a polyether polyol and a difunctional isocyanate are prepolymerized to obtain a silicone oil prepolymer and a polyether polyol prepolymer, 1,4-diamino-2-butene is added to the silicone oil prepolymer for chain extension reaction, and then a polyethylene glycol prepolymer is added to continue the reaction, and finally hydroxyethyl methacrylate or hydroxypropyl methacrylate is added for end-capping to obtain the polyurethane acrylate oligomer.

2. A Tencel digital printing process according to claim 1, characterized in that: The acryloyl chloride compound includes at least one of methacryloyl chloride, 3-methylcrotonoyl chloride or crotonoyl chloride.

3. A Tencel digital printing process according to claim 1 or 2, characterized in that: The pigment is a surface-modified pigment of a vinyl silane coupling agent; the vinyl silane coupling agent is at least one of vinyl trimethoxy silane, vinyl triethoxy silane and gamma-methacryloxypropyl trimethoxy silane.

4. A Tencel digital printing process according to claim 3, characterized in that: The difunctional isocyanate is at least one of isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate or hexamethylene diisocyanate; And / or, the viscosity of the polyurethane acrylate oligomer at 25° C. is ≤2.5 Pa·s.

5. The Tencel digital printing process according to claim 3, characterized in that: The method for preparing the vinyl silane coupling agent surface-modified pigment is as follows: dispersing the pigment in an aqueous solution of the vinyl silane coupling agent, adding acid or alkali and stirring to react, performing solid-liquid separation, washing, and drying to obtain the vinyl silane coupling agent surface-modified pigment.

6. The Tencel digital printing process according to claim 1, characterized in that: The boiling point of the solvent is lower than 120°C; And / or, the mass percentage of the acryloyl chloride compound in the pretreatment liquid is 2% to 8%; and / or, the fabric pretreatment adopts one of the following methods: dipping, padding, spraying or coating; And / or, the drying temperature is 90-150° C. and the drying time is 3-6 hours; And / or, the pigment printing ink comprises, calculated by mass percentage, 30% to 50% of polyurethane acrylate oligomer, 47% to 68% of free radical active diluent, 0.5% to 1% of photoinitiator, and 1% to 2% of pigment.

7. The Tencel digital printing process according to claim 1, characterized in that: The free radical active diluent is at least one of ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, isooctyl (meth)acrylate, hydroxyethyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl acrylate or hydroxypropyl (meth)acrylate; And / or, the photoinitiator is at least one of an aromatic ketone initiator, an α-hydroxyalkyl phenone initiator, a thioxanthone derivative and an organic metallocene initiator.

8. The Tencel digital printing process according to claim 7, characterized in that: The photoinitiator is one of camphorquinone, benzoin dimethyl ether, α-hydroxycyclohexyl benzophenone and isopropylthioxanthone.

9. The Tencel digital printing process according to claim 1, characterized in that: The photocuring refers to the radiation curing of the digital inkjet printed fabric using light with a wavelength of 200-480 nm.

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