Gradient micro-cavity transfer paper structure for deep ground color jean fabric and preparation method of gradient micro-cavity transfer paper structure

Abstract

The invention discloses a gradient micro-cavity transfer paper structure for deep ground color jean fabric. The gradient micro-cavity transfer paper structure comprises a base material layer, a near base material layer, a transition layer and a far base material layer which are arranged from bottom to top, wherein the near base material layer, the transition layer and the far base material layer are all formed by mixing and curing nano silicon dioxide, waterborne polyurethane, a PEG-PPG (Polyethylene Glycol-Polypropylene Glycol) block copolymer, a dispersing agent and water; by controlling the component proportion of the far base material layer, the transition layer and the near base material layer, three layers of pore channels with gradually decreased average pore sizes from top to bottom are formed, ink droplets are rapidly adsorbed by macropores on the far base material layer and permeate into the near base material layer, mesopores in the transition layer serve as a buffer, and micropores in the near base material layer decelerate the migration of ink, so that the ink migration speed is increased. Therefore, the retention time of the ink in the near substrate layer is prolonged, the reverse osmosis problem is avoided, the ink permeation rate is low, the pore deformation rate during calendaring is low, and the dark color covering effect is good.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of textile materials, and in particular to a gradient microcavity transfer paper structure for deep-colored denim fabric and a preparation method thereof. BACKGROUND

[0002] Transfer paper refers to a paper with a pattern printed thereon, and the pattern of the paper can be transferred to other surfaces. Generally, the transfer paper is transferred with the front surface facing down, the transfer paper is tightly attached to the second surface, and then the back paper is removed to complete the transfer of the pattern.

[0003] As a global annual consumption of more than 7 billion meters of supporting textile, the deep color product of denim fabric (especially INDIGO 14# standard dark blue) accounts for more than 65% of the market share, but the traditional transfer printing technology has three structural defects: first, the traditional homogeneous ink absorption layer (pore diameter of 2-3 pm) cannot effectively block the penetration of the pigment of the deep-colored denim fabric when in use, resulting in a large color difference between the white ink layer and the dark blue base cloth, the deep color covering failure, far exceeding the industry threshold color difference DE ≤ 2.0, thereby forcing enterprises to adopt a secondary overprinting process, resulting in a sharp increase in cost and a decrease in production line efficiency. Second, the essence of ink penetration is fluid mechanics imbalance, when the ink pressure is greater than the capillary locking force (ΔP ≈ 2.8 kPa), ink penetration is likely to occur, resulting in blurred pattern edges, ink penetration into fiber gaps, especially for light gradient patterns, the ink penetration width can reach 0.3-0.5 mm, and the industry average yield is suppressed at 82%. Third, the homogeneous structure of the ink absorption layer has low strength during calendering, and the pores are easily deformed, thereby affecting the subsequent ink absorption effect and reducing the yield of the ink absorption paper. Therefore, in order to solve the problems of poor deep color covering effect, low yield caused by ink penetration and pore deformation of the traditional transfer paper, it is urgent to develop a gradient microcavity transfer paper structure for deep-colored denim fabric with good deep color covering effect, low ink penetration rate and low pore deformation rate and a preparation method thereof. SUMMARY

[0004] The purpose of the present application is achieved by adopting the following technical solutions: The gradient microcavity transfer paper structure for deep base color jean fabric comprises, from bottom to top, a substrate layer, a near-substrate layer, a transition layer and a far-substrate layer; wherein the near-substrate layer, the transition layer and the far-substrate layer are all formed by mixing and curing nano-silicon dioxide, water-based polyurethane, PEG-PPG block copolymer, dispersant and water; the average particle size of the nano-silicon dioxide in the near-substrate layer is 0.15-0.18 μm, the cross-linking degree of the water-based polyurethane is 90%, and the molecular weight of the PEG-PPG block copolymer is 800 g / mol; the mass ratio of the nano-silicon dioxide, the water-based polyurethane, the PEG-PPG block copolymer, the dispersant and water is (52-58):(35-36):(8-13):5:100; the average particle size of the nano-silicon dioxide in the transition layer is 0.8-1.0 μm, the cross-linking degree of the water-based polyurethane is 75%, and the molecular weight of the PEG-PPG block copolymer is 2000 g / mol; the mass ratio of the nano-silicon dioxide, the water-based polyurethane, the PEG-PPG block copolymer, the dispersant and water is 50:30:15:5:100; the average particle size of the nano-silicon dioxide in the far-substrate layer is 4.6-5.0 μm, the cross-linking degree of the water-based polyurethane is 60%, the molecular weight of the PEG-PPG block copolymer is 4000 g / mol, and the mass ratio of the nano-silicon dioxide, the water-based polyurethane, the PEG-PPG block copolymer, the dispersant and water is 45:25:20:5:100.

[0005] Preferably, the substrate layer is made of PET material.

[0006] Preferably, the dispersant is sodium polyacrylate.

[0007] Preferably, the substrate layer is subjected to corona treatment.

[0008] The substrate layer is subjected to corona treatment, so as to improve the surface tension of the substrate layer and provide a good adhesion basis for subsequent processes.

[0009] Preferably, the average pore size ratio of the far-substrate layer to the near-substrate layer is not less than 18:1.

[0010] By controlling the nano-silicon dioxide particle size ratio of the far-substrate layer to the near-substrate layer, the pore size ratio of the communication pores of the far-substrate layer to the near-substrate layer is controlled, so as to ensure the differential pressure of capillary adhesion between the far-substrate layer and the near-substrate layer, thereby avoiding ink reverse infiltration from the near-substrate layer to the far-substrate layer and reducing the ink infiltration rate.

[0011] The application further provides a preparation method of the gradient microcavity transfer paper structure for deep base color jean fabric, comprising the following steps: S1, a biaxially stretched PET film is used as the substrate layer, and the substrate layer is subjected to corona treatment; S2, respectively, according to the composition of the near substrate layer, transition layer and far substrate layer, the corresponding nanometer silicon dioxide, water-based polyurethane, PEG-PPG block copolymer, dispersant and water are mixed uniformly and defoamed; S3, a three-chamber slit coater is used to coat the near substrate layer, transition layer and far substrate layer on the substrate layer at the same time, and the substrate layer, near substrate layer, transition layer and substrate layer are distributed from bottom to top; S4, after the coating of step S3 is completed, hot air curing at 80℃ for 30S, then infrared fixation at 100℃ for 40S, and then microwave curing at 130℃ for 50S; finally, calendering treatment is performed.

[0012] Three-chamber slurry is simultaneously extruded, and the viscosity of the mixed components of the near substrate layer, transition layer and original substrate layer is matched, the slurry of the three-chamber is coated on the substrate layer at the same time, the coating efficiency is high, and through self-laminating curing, a transition zone is formed between the layers, the bonding force between the layers is improved, and the interface peeling problem of traditional multi-layer coating is eliminated.

[0013] Preferably, in step S3, the near substrate layer forms a 10μm wet coating layer under an extrusion pressure of 0.4Mpa; the transition layer forms a 15μm wet coating layer under an extrusion pressure of 0.25Mpa; and the far substrate layer forms a 80μm wet coating layer under an extrusion pressure of 0.15Mpa.

[0014] Preferably, in step S1, the thickness of the substrate layer is 88-92μm, the corona treatment voltage is 8-10Kv, and the treatment speed is 15m / min.

[0015] Preferably, in step S4, the microwave power is 3kW, the microwave frequency is 2.45GHz; the line pressure of calendering treatment is 1.2MPa, the calendering roller temperature is 68-72℃, and the calendering speed is 8m / min.

[0016] Compared with the prior art, the beneficial effects of the present application are: The present application controls the component proportion of the far substrate layer, the transition layer and the near substrate layer, the average pore size of each layer is dominated by the particle size, content and packing method of nano-silica, the gap between the nano-silica particles corresponding to the particle size is expanded into connected pores by the PEG-PPG block copolymer, forming a three-layer average pore size gradient decreasing pore from top to bottom, the ink drop is quickly absorbed and penetrated to the near substrate layer in the far substrate layer, the pores in the transition layer act as a buffer, and the micropores in the near substrate layer slow down the migration of the ink, thereby increasing the residence time of the ink in the near substrate layer; the capillary adsorption force of the ink in the micropores of the near substrate layer is much greater than that of the ink in the far substrate layer, and the difference in capillary adsorption force generated by the pore size gradient forms a one-way valve effect, forcing the ink to migrate from the far substrate layer to the near substrate layer, avoiding the problem of reverse penetration, and the ink penetration rate is low; the pore size of the micropores of the near substrate layer is smaller than the particle size of the indigo pigment of the dark blue jean fabric, solving the problem of poor dark covering effect caused by the upward penetration of indigo pigment; the near substrate layer forms a rigid skeleton by high content of nano-silica and high cross-linked polyurethane, and has strong structural strength, and the porosity deformation rate is low during calendering. DETAILED DESCRIPTION

[0017] To make the technical problems solved by the present application, the technical solutions adopted and the technical effects achieved more clear, the technical solutions of the embodiments of the present application will be further described in detail below. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application. EMBODIMENT

[0018] A gradient microcavity transfer paper structure for deep base color denim fabric, comprising a substrate layer, a near substrate layer, a transition layer and a far substrate layer arranged from bottom to top; wherein the near substrate layer, the transition layer and the far substrate layer are all formed by mixing and curing nano-silicon dioxide, water-based polyurethane, PEG-PPG block copolymer, sodium polyacrylate and water; the average particle size of the nano-silicon dioxide in the near substrate layer is 0.18μm, the crosslinking degree of the water-based polyurethane is 90%, and the molecular weight of the PEG-PPG block copolymer is 800g / mol; the mass ratio of the nano-silicon dioxide, the water-based polyurethane, the PEG-PPG block copolymer, the sodium polyacrylate and the water is 55:35:10:5:100, and the viscosity after mixing is 3400-3600cP; the average particle size of the nano-silicon dioxide in the transition layer is 0.9μm, the crosslinking degree of the water-based polyurethane is 75%, and the molecular weight of the PEG-PPG block copolymer is 2000g / mol; the mass ratio of the nano-silicon dioxide, the water-based polyurethane, the PEG-PPG block copolymer, the sodium polyacrylate and the water is 50:30:15:5:100, and the viscosity after mixing is 1150-1250cP; the average particle size of the nano-silicon dioxide in the far substrate layer is 4.8μm, the crosslinking degree of the water-based polyurethane is 60%, the molecular weight of the PEG-PPG block copolymer is 4000g / mol, and the mass ratio of the nano-silicon dioxide, the water-based polyurethane, the PEG-PPG block copolymer, the sodium polyacrylate and the water is 45:25:20:5:100, and the viscosity after mixing is 480-520cP.

[0019] The substrate layer is made of PET material.

[0020] The embodiment also provides a preparation method of the gradient microcavity transfer paper structure for deep base color denim fabric, comprising the following steps: S1, a biaxially stretched PET film is used as the substrate layer, and the substrate layer is subjected to corona treatment; in step S1, the thickness of the substrate layer is 88-92μm, the corona treatment voltage is 8-10Kv, and the treatment speed is 15m / min.

[0021] S2, the corresponding nano-silicon dioxide, water-based polyurethane, PEG-PPG block copolymer, sodium polyacrylate and water are mixed uniformly according to the compositions of the near substrate layer, the transition layer and the far substrate layer, and then defoaming is performed; S3, a three-chamber slot coater is used to simultaneously coat the near substrate layer, the transition layer and the far substrate layer on the substrate layer, and the substrate layer, the near substrate layer, the transition layer and the far substrate layer are arranged from bottom to top; in step S3, the near substrate layer forms a wet coating layer with a thickness of 10μm under an extrusion pressure of 0.4Mpa; the transition layer forms a wet coating layer with a thickness of 15μm under an extrusion pressure of 0.25Mpa; and the far substrate layer forms a wet coating layer with a thickness of 80μm under an extrusion pressure of 0.15Mpa; S4, after coating is completed in step S3, hot air curing at 80℃ for 30S, then infrared fixation at 100℃ for 40S, and then microwave curing at 130℃ for 50S; finally, perform the calendering treatment.

[0022] In step S4, the microwave power is 3kW, and the microwave frequency is 2.45GHz; the line pressure for the calendering treatment is 1.2MPa, the calendering roller temperature is 68-72℃, and the calendering speed is 8m / min.

[0023] In this example, the mercury intrusion method is used to test the pore size of the near-substrate layer, the transition layer, and the far-substrate layer. The steps are as follows: 1. Sample preparation: accurately cut a 2cm x 2cm sample from the transfer paper, and dry it at 105℃ for 2 hours to remove moisture.

[0024] 2. Sample loading: place the sample into an expansion meter with a known weight, and vacuum it to <6.7 Pa.

[0025] 3. Low-pressure testing: measure the macropores (5-400μm) under a pressure of 0.0014-0.21 MPa.

[0026] 4. High-pressure testing: measure the micropores (0.005-5μm) under a pressure of 0.21-400 MPa.

[0027] The average pore size of the near-substrate layer is measured to be 0.2μm, the average pore size of the transition layer is measured to be 1.0μm, and the average pore size of the far-substrate layer is measured to be 5.0μm. Example

[0028] This example is similar to Example 1, except that the average particle size of the nanosilica in the near-substrate layer is 0.18μm, the cross-linking degree of the water-based polyurethane is 90%, the molecular weight of the PEG-PPG block copolymer is 800g / mol; the mass ratio of nanosilica, water-based polyurethane, PEG-PPG block copolymer, sodium polyacrylate, and water is 52:35:13:5:100; and the average pore size of the near-substrate layer is expanded to 0.25μm. Example

[0029] This example is similar to Example 1, except that the average particle size of the nanosilica in the near-substrate layer is 0.15μm, the cross-linking degree of the water-based polyurethane is 90%, the molecular weight of the PEG-PPG block copolymer is 800g / mol; the mass ratio of nanosilica, water-based polyurethane, PEG-PPG block copolymer, sodium polyacrylate, and water is 58:36:8:5:100; and the average pore size of the near-substrate layer is reduced to 0.15μm.

[0030] Comparative Example 1 The comparative example is similar to Example 1, except that the average particle size of the nanosilica in the near-substrate layer is 0.18 pm, the cross-linking degree of the aqueous polyurethane is 90%, the molecular weight of the PEG-PPG block copolymer is 800 g / mol; the mass ratio of nanosilica, aqueous polyurethane, PEG-PPG block copolymer, sodium polyacrylate and water is 50:35:17:5:100, and the average pore size of the channels in the near-substrate layer is expanded to 0.30 pm.

[0031] Comparative Example 2 The comparative example is similar to Example 1, except that the average particle size of the nanosilica in the near-substrate layer is 0.18 pm, the cross-linking degree of the aqueous polyurethane is 90%, the molecular weight of the PEG-PPG block copolymer is 800 g / mol; the mass ratio of nanosilica, aqueous polyurethane, PEG-PPG block copolymer, sodium polyacrylate and water is 45:35:22:5:100, and the average pore size of the channels in the near-substrate layer is expanded to 0.80 pm.

[0032] Example 1-3 and Comparative Example 1-2 were subjected to ink penetration rate testing (AATCC 130), the steps of which are as follows: 1. Transfer a light gray gradient pattern (20% ink coverage).

[0033] 2. Cut the sample (5x5 cm) and place it under a fiber analysis microscope (Keyence VHX-7000).

[0034] 3. Measure the ink penetration width area.

[0035] 4. Calculate the ink penetration rate: Ink penetration rate = (ink penetration area / total pattern area) x 100%.

[0036] Take three sets of average values.

[0037] The measured ink penetration rate results are shown in Table 1.

[0038]

[0039] It can be seen that when the average pore size of the far-substrate layer: the average pore size of the near-substrate layer is greater than 20:1, the ink penetration rate is less than 5%.

[0040] Comparative Example 3 The comparative example is similar to the example, except that the comparative example is a homogeneous ink absorption layer without the near-substrate layer, transition layer and far-substrate layer, and the components of the ink absorption layer are nano-silica with an average particle size of 3.0 pm, waterborne polyurethane with a crosslinking degree of 75, PEG-PPG block copolymer, sodium polyacrylate and water in a mass ratio of 55:35:15:5:100, and the ink absorption layer is one layer coated directly on the substrate layer of the PET film, 100°C hot air curing, and the rest is consistent with the example. The thickness of the final transfer paper is consistent with example 1.

[0041] The color difference AE, ink penetration rate, ink utilization rate, ink carrying capacity, pore deformation rate and ink droplet retention time of example 1 and comparative example 3 were tested respectively. The specific values are shown in Table 2.

[0042] The color difference AE test (ISO 2470) has the following steps: 1. Transfer a white pattern (10x10 cm) to denim (L*=16.3).

[0043] 2. Measure using a spectrophotometer (X-Rite i7): White ink area LAB value (L1, a1, b1), Ground cloth area LAB value (L2, a2, b2).

[0044] 3. Calculate: AE=[(L1-L2) 2 +(a1-a2) 2 +(b1-b2) 2 ] 1 / 2 Take the average of 5 points.

[0045] The ink utilization rate test has the following steps: 1. Ink marking: add 0.01wt% yttrium aluminum garnet (YAG) fluorescent powder (particle size 0.3 pm).

[0046] 2. After transfer, scan the cross section with a laser confocal microscope (Leica TCS SP8): excitation wavelength: 488 nm, emission wavelength: 530 nm.

[0047] 3. Calculate the capture rate: Capture rate = amount of fluorescent signal in ink absorption layer / total amount of ink fluorescent signal x 100%.

[0048] The ink carrying capacity test (ASTM D5402) has the following steps: 1. Weigh the dry weight of the transfer paper m0 (precision 0.1 mg).

[0049] 2. Uniformly coat the ink (1 mL / m²), stand for 30 s.

[0050] 3. Remove unabsorbed ink (air knife pressure 0.1 MPa).

[0051] 4. Weigh the wet weight m1.

[0052] 5. Calculate: Carrying capacity = (m1-m0) / (p A); p: ink density; A: effective ink absorption area of the material (unit: cm2).

[0053] Pore deformation rate test method: mercury intrusion method (ISO 15901); equipment: Micromeritics AutoPore V; pressure range: 0.1-400 MPa; calculation: Deformation rate = (Vp-Va) / Vp x 100%; Vp: pore volume before pressing, Va: volume after pressing.

[0054] Ink drop migration speed test: high-speed camera analysis is used; equipment: Phantom VEO 710L (5000 fps); ink mark: 0.1% fluorescein sodium (λex=490 nm); measurement: time difference of ink drop from contact surface to disappearance, calculate migration speed.

[0055]

[0056] The above embodiments are only some preferred embodiments of the present application, and cannot be used to limit the scope of protection of the present application. Any non-essential changes and substitutions made by those skilled in the art on the basis of the present application shall fall within the scope of protection of the present application.

Claims

1. A gradient microcavity transfer paper structure for deep base denim, characterized by The application discloses a multilayered PET film, which comprises a substrate layer, a near-substrate layer, a transition layer and a far-substrate layer arranged from bottom to top; wherein the near-substrate layer, the transition layer and the far-substrate layer are all formed by mixing nano-silica, water-based polyurethane, PEG-PPG block copolymer, dispersant and water and then curing; the average particle size of the nano-silica in the near-substrate layer is 0.15-0.18 microns, the cross-linking degree of the water-based polyurethane is 90%, and the molecular weight of the PEG-PPG block copolymer is 800 g / mol; the mass ratio of the nano-silica, the water-based polyurethane, the PEG-PPG block copolymer, the dispersant and water is (52-58):(35-36):(8-13):5:100; the average particle size of the nano-silica in the transition layer is 0.8-1.1 microns, the cross-linking degree of the water-based polyurethane is 75%, and the molecular weight of the PEG-PPG block copolymer is 2000 g / mol; the mass ratio of the nano-silica, the water-based polyurethane, the PEG-PPG block copolymer, the dispersant and water is 50:30:15:5:100; the average particle size of the nano-silica in the far-substrate layer is 4.6-5.0 microns, the cross-linking degree of the water-based polyurethane is 60%, the molecular weight of the PEG-PPG block copolymer is 4000 g / mol, and the mass ratio of the nano-silica, the water-based polyurethane, the PEG-PPG block copolymer, the dispersant and water is 45:25:20:5:

100.

2. The gradient microcavity transfer paper structure for deep base denim fabrics according to claim 1, wherein, The substrate layer is made of PET material.

3. The gradient microcavity transfer paper structure for deep base denim fabrics according to claim 2, wherein, The dispersant is sodium polyacrylate.

4. The gradient microcavity transfer paper structure for deep base denim fabrics according to claim 3, wherein, The substrate layer is subjected to corona treatment.

5. The gradient microcavity transfer paper structure for dark denim fabrics according to claim 4, wherein, The average pore size ratio of the far-substrate layer to the near-substrate layer is not less than 20:

1.

6. A method of making a gradient microcavity transfer paper structure for deep base denim fabric as claimed in claim 5, characterized by The application further discloses a preparation method of the multilayered PET film. S1, a biaxially stretched PET film is used as the substrate layer, and the substrate layer is subjected to corona treatment; S2, the corresponding nano-silica, water-based polyurethane, PEG-PPG block copolymer, dispersant and water are uniformly mixed and degassed according to the compositions of the near-substrate layer, the transition layer and the far-substrate layer respectively; S3, a three-chamber slot coater is used to simultaneously coat the near-substrate layer, the transition layer and the far-substrate layer on the substrate layer, and the substrate layer, the near-substrate layer, the transition layer and the far-substrate layer are arranged from bottom to top; S4, after the coating of step S3 is completed, the film is subjected to hot air curing at 80 DEG C for 30 seconds, infrared curing at 100 DEG C for 40 seconds and microwave curing at 130 DEG C for 50 seconds, and finally subjected to calendering treatment.

7. The method of claim 6, wherein the gradient microcavity transfer paper structure for deep base denim fabric is prepared by the steps of: In step S3, the near-substrate layer is formed into a 10-micron wet coating layer under an extrusion pressure of 0.4 MPa, the transition layer is formed into a 15-micron wet coating layer under an extrusion pressure of 0.25 MPa, and the far-substrate layer is formed into an 80-micron wet coating layer under an extrusion pressure of 0.15 MPa.

8. The method of claim 7, wherein the gradient microcavity transfer paper structure for deep base denim fabric is prepared by the steps of: In step S1, the thickness of the substrate layer is 88-92 microns, the corona treatment voltage is 8-10 Kv, and the treatment speed is 15 m / min.

9. The method of claim 8, wherein the gradient microcavity transfer paper structure for deep base denim fabric is prepared by the steps of: In step S4, the microwave power is 3 kW, the microwave frequency is 2.45 GHz; the linear pressure of calendering treatment is 1.2 MPa, the calendering roller temperature is 68-72 ℃, and the calendering speed is 8 m / min.

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