An environmentally friendly water-based skin-friendly covering paste with a release paper-free effect, its preparation method and application

Abstract

The present invention discloses an environmentally friendly water-based skin-friendly covering paste with the effect of eliminating the need for release paper, its preparation method and application, belonging to the field of printing and dyeing technology. The environmentally friendly water-based skin-friendly covering paste with the effect of eliminating the need for release paper comprises the following components in parts by weight: PU matte emulsion: 60-73 parts, water: 2-7 parts, dispersant: 0.1-1 part, humectant: 5-8 parts, silicone oil: 17-23 parts, emulsifier: 0.5-2 parts, thickener: 1-5 parts. The environmentally friendly water-based skin-friendly covering paste of the present invention has no flash, high dullness, good fastness, soft hand feeling, moisture absorption resistance after covering the surface, and can also be printed with printing paste, thick plate and other processes after covering the surface without delaminating. It breaks the requirement of traditional use of release paper, is particularly dry and non-sticky after covering the surface, does not reflect light after a long time, and has a strong skin feeling.

Description

Technical Field

[0001] The present invention relates to the field of printing and dyeing technology, and particularly relates to an environmentally friendly water-based skin-friendly covering paste with the effect of eliminating the need for release paper, its preparation method and application. Background Art

[0002] In the textile printing industry, with the continuous improvement of consumers' requirements for product quality, environmental protection and production efficiency, the release paper materials widely used in traditional printing processes not only increase production costs, but also bring problems such as cumbersome subsequent processing, resource waste and environmental pollution. Especially in the fields of high-grade textiles such as clothing and home accessories, there are extremely high requirements for the clarity, color saturation and hand feeling comfort of printed patterns. Traditional covering pastes often need to be protected by release paper after printing to prevent damage or adhesion of the printed surface during subsequent processing or transportation. This process is not only time-consuming and laborious, but also restricts the improvement of production efficiency.

[0003] Traditional plastic bags contain plasticizers, and the plasticizers may migrate from the plastic bags to the printed surface in contact with them over time, resulting in the matte effect on the printed surface becoming shiny, affecting the appearance quality of textiles. At the same time, the precipitation of plasticizers may also damage the integrity of the printed pattern, causing oil stains or other defects on the surface, thereby reducing the service life and aesthetic degree of the product. To address these challenges, there is an increasing demand in the market for covering paste products that eliminate the need for release paper, especially products that can maintain the stability of the printed surface effect and are not affected by plasticizers without the need for release paper after printing, which have broad market application prospects. Summary of the Invention

[0004] Based on the problems existing in the background art, the present invention provides an environmentally friendly water-based skin-friendly covering paste with the effect of eliminating the need for release paper, which can effectively prevent the influence of plasticizers on the printed surface, simplify the production process and improve production efficiency.

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

[0006] The first aspect of the present invention discloses an environmentally friendly water-based skin-friendly covering paste with the effect of eliminating the need for release paper, which comprises the following components in parts by weight: PU matte emulsion: 60 - 73 parts, water: 2 - 7 parts, dispersant: 0.1 - 1 part, humectant: 5 - 8 parts, silicone oil: 17 - 23 parts, emulsifier: 0.5 - 2 parts, thickener: 1 - 5 parts.

[0007] Further, the preparation of the PU matte emulsion specifically includes the following operations: Under a nitrogen atmosphere, isophorone diisocyanate, polypropylene glycol, and dimethylolpropionic acid are added to a reactor, and the temperature is raised to 90 °C and stirred for 3 h. After the reaction is completed, the temperature is lowered to room temperature to obtain a polyurethane prepolymer; Triethylamine and 3-aminopropyltrimethoxysilane as a salifying agent are added to the polyurethane prepolymer, stirred for 30 min, and then water is added for high-speed emulsification for 1 h, and the organic solvent is removed under reduced pressure to obtain the PU matte emulsion.

[0008] Further, the molecular weight of the polypropylene glycol is 1000 - 3000.

[0009] Further, the dosage of 3-aminopropyltrimethoxysilane is 0.2 - 0.8% of isophorone diisocyanate.

[0010] Further, the solid content of the PU matte emulsion is 40 ± 1%.

[0011] Further, the PU matte emulsion also includes a matting agent, and the matting agent is any one of silica, wax particles, and inorganic particles. The matting agent accounts for 1 - 3% of the mass in the PU matte emulsion.

[0012] Further, the silicone oil is polyether-modified amino-block silicone oil;

[0013] The dispersant is polyvinyl alcohol;

[0014] The humectant is one or several of ethylene glycol, propylene glycol, or glycerol;

[0015] The emulsifier is one or more of sodium dodecylbenzenesulfonate, Tween 80, or sodium dodecyl alcohol polyoxyethylene ether sulfate;

[0016] The thickener is Rheovis PU 1191.

[0017] The second aspect of the present invention discloses a preparation method of an environmentally friendly water-based skin-friendly cover coating slurry with a non-isolation paper effect, including the following steps:

[0018] (1) Put the PU matte emulsion and water into a dispersion tank, start the stirrer, and stir evenly to obtain a mixture A;

[0019] (2) Continue to add a dispersant, a humectant, and an emulsifier to the mixture A, disperse for 3 - 5 min, and then add silicone oil and disperse for 20 - 30 min to obtain a mixture B;

[0020] (3) Adjust the viscosity of the mixture B with a thickener, filter, and package to obtain the water-based skin-friendly cover coating slurry with a non-isolation paper effect.

[0021] Further, in step (3), the viscosity of the mixture B is adjusted to 50,000 - 70,000 Pa·S.

[0022] Further, step (1) includes:

[0023] Put the PU matte emulsion and water into the dispersion tank, automatically control the mixer to run for a first preset duration and then pause stirring;

[0024] Turn on the lighting lamp at the top of the dispersion tank and the light intensity detection module at the bottom, and collect the light intensity parameters of the light passing through the liquid in the dispersion tank;

[0025] Compare the collected light intensity parameters with the preset light intensity threshold. If the light intensity parameters are greater than the preset light intensity threshold, stop stirring; otherwise, control the mixer to run for a second preset duration and then perform light intensity detection and intensity judgment again.

[0026] The third aspect of the present invention discloses the application of an environmentally friendly water-based skin-friendly covering paste with a release paper-free effect. The specific operation is as follows: Mix the environmentally friendly water-based skin-friendly covering paste with a release paper-free effect evenly with a crosslinking aid, cover it on the printed machine-printed glue paste twice, let it stand overnight, and overheat at 120 °C for 2 minutes.

[0027] The crosslinking aid is CX-100, and the dosage is 0.5-1.5% of the total weight of the covering paste.

[0028] Advantages of the present invention:

[0029] 1. After covering with the environmentally friendly water-based skin-friendly covering paste with a release paper-free effect of the present invention, there is no flash, high dullness, good fastness, soft hand feeling, moisture absorption resistance, and it can also be printed with glue paste, thick plate, etc. after covering without delaminating. It breaks the traditional requirement of using release paper, is extremely dry after covering, does not stick back, does not reflect light after a long time, and has a strong skin feeling.

[0030] 2. In the present invention, a water-based PU matte emulsion is used, reducing the dependence on organic solvents, meeting environmental protection requirements, reducing the emission of VOC (volatile organic compounds), and being beneficial to reducing the harm to the environment and human health. By optimizing the ratio of the water-based PU matte emulsion and silicone oil, the adhesion phenomenon during the printing process can be effectively reduced, a release paper-free effect can be provided, the production efficiency can be improved, and the production cost can be reduced, especially more advantageous in large-scale industrial applications. Description of the Drawings

[0031] The drawings are used to provide further explanation of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention, and do not constitute a limitation to the present invention. In the drawings:

[0032] Figure 1 It is the effect diagram after using the environmentally friendly water-based skin-friendly covering paste with a release paper-free effect in Example 1;

[0033] Figure 2 It is the effect diagram after using the covering paste in Comparative Example 1. Detailed implementation mode

[0034] The following further details the technical solution of the present invention in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0035] Example 1

[0036] An environmentally friendly water-based skin-friendly topcoat slurry with the effect of eliminating the release paper, comprising the following components by weight: PU matte emulsion: 67 parts, water: 4.5 parts, dispersant: 0.5 part, humectant: 6 parts, silicone oil: 20 parts, emulsifier: 1 part, thickener.

[0037] Among them, the preparation of the PU matte emulsion specifically includes the following operations: Add 16 g of isophorone diisocyanate, 65.3 g of polypropylene glycol (molecular weight 2000), and 4.5 g of dimethylolpropionic acid to the reactor under a nitrogen atmosphere, heat up to 90 °C and stir for 3 h. During the reaction, add the diluent acetone. After the reaction is completed, cool to room temperature to obtain a polyurethane prepolymer; add 3.3 g of the salt-forming agent triethylamine and 3-aminopropyltrimethoxysilane to the polyurethane prepolymer. The dosage of 3-aminopropyltrimethoxysilane is 0.5% of the isophorone diisocyanate, stir and react for 30 min, continue to add water and emulsify at high speed for 1 h, and remove the organic solvent under reduced pressure to obtain the PU matte emulsion. The solid content of the finally prepared PU matte emulsion is 40 ± 1%. The PU matte emulsion also includes a matting agent, and the matting agent is silica, and the matting agent accounts for 2% of the mass in the PU matte emulsion.

[0038] The silicone oil is polyether-modified amino-block silicone oil;

[0039] The dispersant is polyvinyl alcohol;

[0040] The humectant is glycerol;

[0041] The emulsifier is Tween 80;

[0042] The thickener is Rheovis PU 1191.

[0043] The preparation method of the environmentally friendly water-based skin-friendly topcoat slurry with the effect of eliminating the release paper includes the following steps:

[0044] (1) Put the PU matte emulsion and water into the dispersion tank, start the stirrer, and stir evenly to obtain mixture A;

[0045] (2) Continue to add the dispersant, humectant, and emulsifier to mixture A, disperse for 5 min, and then add the silicone oil and disperse for 30 min to obtain mixture B;

[0046] (3) Adjust the viscosity of mixture B to 60,000 Pa·S with a thickening agent, filter it, and then package it to obtain an aqueous skin covering paste with the effect of eliminating the need for release paper.

[0047] Specifically, step (2) further includes:

[0048] Put the PU matte emulsion and water into the dispersion tank, automatically control the mixer to run for the first preset duration and then pause stirring;

[0049] Turn on the lighting lamp at the top of the dispersion tank and the light intensity detection module at the bottom, and collect the light intensity parameters passing through the liquid in the dispersion tank;

[0050] Compare the collected light intensity parameters with the preset light intensity threshold. If the light intensity parameters are greater than the preset light intensity threshold, stop stirring; otherwise, control the mixer to run for the second preset duration and then perform light intensity detection and intensity judgment again.

[0051] Preferably, after the PU matte emulsion and water are put into the dispersion tank, start the mixer and start timing. When the stirring duration reaches the first preset duration, pause the stirring of the mixer.

[0052] Preferably, the light intensity detection module includes a photosensitive sensor array composed of multiple photosensitive sensors; obtain the respective sub-light intensity parameters through multiple photosensitive sensors; compare each sub-light intensity parameter with the preset light intensity threshold, and determine the proportion of the number of sub-light intensity parameters greater than the preset light intensity threshold in all sub-light intensity parameters. When this proportion is greater than the preset proportion, it is determined that the light intensity parameters detected by the light intensity detection module are greater than the preset light intensity threshold, and stop stirring; otherwise, it is determined that the light intensity parameters detected by the light intensity detection module are not greater than the preset light intensity threshold, and control the mixer to run for the second preset duration and then perform light intensity detection and intensity judgment again.

[0053] Thus, obtain the light intensity parameters at multiple positions through multiple photosensitive sensors in the light intensity detection module, and use the proportion that meets the light intensity requirements to more accurately reflect the light transmittance of the liquid in the current dispersion tank, and then evaluate the uniformity of the current liquid stirring to control whether to perform further stirring.

[0054] Example 2

[0055] The difference from Example 1 is that the PU matte emulsion is 70 parts, the silicone oil is 18 parts, and the other components and preparation methods are the same as those in Example 1.

[0056] Example 3

[0057] The difference from Example 1 is that the dosage of 3-aminopropyltrimethoxysilane in the preparation of the PU matte emulsion is 0.8% of isophorone diisocyanate.

[0058] Comparative Example 1

[0059] The difference from Example 1 is that 3-aminopropyltrimethoxysilane is not added during the preparation of the PU matte emulsion; the silicone oil is methyl silicone oil.

[0060] Comparative Example 2

[0061] The difference from Example 1 is that 3-aminopropyltrimethoxysilane is not added during the preparation of the PU matte emulsion.

[0062] Comparative Example 3

[0063] The difference from Example 1 is that the dosage of 3-aminopropyltrimethoxysilane in the preparation of the PU matte emulsion is 1.5% of isophorone diisocyanate.

[0064] Comparative Example 4

[0065] The difference from Example 1 is that the silicone oil is methyl silicone oil.

[0066] Comparative Example 5

[0067] The difference from Example 1 is that the silicone oil is amino-modified silicone oil.

[0068] Comparative Example 6

[0069] The difference from Example 1 is that the silicone oil is polyether-modified silicone oil.

[0070] Application Example

[0071] The covering pastes prepared in Examples 1-3 and Comparative Examples 1-6 were respectively mixed with a crosslinking aid CX-100 (dosage: 1.0% of the total weight of the covering paste), and applied twice on the printed machine-printed rubber paste, left to stand overnight, and overheated at 120 °C for 2 minutes; Application Examples 1-9 were obtained.

[0072] Test Example

[0073] Light-changing performance of the adhesive bag: From Figure 1-2 It can be seen that the water-based skin covering paste with the effect of eliminating the release paper prepared by the present invention does not change in light, while the covering paste in Comparative Example 1 will have partial light change.

[0074] Glossiness test: The fabric samples covered with the covering paste were tested with a glossiness instrument under the standard of 60°, and the test results were recorded; then the fabric samples covered with the covering paste were washed at 60 °C for 10 h, and then tested again with a glossiness instrument under the standard of 60°. Among them, the washing test was carried out according to the A-type washing machine 6N program in the national standard GB / T 8629-2017, and the test results were recorded; the measured results are shown in Table 1.

[0075] Table 1

[0076]

[0077] As can be seen from the results in Table 1, the glossiness values of the fabric samples covered with the topcoat sizing before and after washing did not change, and the glossiness remained at the same level, indicating that the topcoat sizing of the present invention has good water resistance and stability.

[0078] The performance of the fabrics obtained in the above Application Examples 1-9 was tested, and the test methods are as follows:

[0079] Color fastness: Tested according to the test method provided in the national standard GB / T 3920-2008 "Test Method for Colorfastness to Rubbing of Textiles";

[0080] Water resistance: The fabric samples covered with the topcoat sizing obtained were washed at 60 °C for 10 h, and it was observed whether the topcoat sizing part remained intact. If the topcoat sizing part remained intact, the water resistance was recorded as excellent. If slight cracks appeared in the topcoat sizing part, but the topcoat sizing did not peel off, the water resistance was recorded as good. If adhesion, bursting or peeling occurred in the topcoat sizing part, the water resistance was recorded as poor. Among them, the washing test was carried out according to the 6N program of Type A washing machine in the national standard GB / T8629-2017.

[0081] Hand feeling: By the touch method.

[0082] The test results are shown in Table 2.

[0083] Table 2

[0084]

[0085]

[0086] As can be seen from the data in Table 1, the fabric samples of Application Examples 1-3 of the present invention are superior in color fastness, water resistance and hand feeling compared with the fabric samples of Application Examples 4-9.

[0087] Application Example 4 used the cover paste of Comparative Example 1. During the preparation of the PU matte emulsion, 3-aminopropyltrimethoxysilane was not added, and the silicone oil was ordinary methyl silicone oil. It can be seen that the water resistance of the fabric sample was significantly reduced. 3-aminopropyltrimethoxysilane is a silane coupling agent. The siloxane group of 3-aminopropyltrimethoxysilane can react with hydroxyl or amino groups in the matrix to form a cross-linked network. This cross-linking can not only enhance the density of the coating, but also improve the mechanical strength and stability of the coating. In Comparative Example 1, 3-aminopropyltrimethoxysilane was not added, the density of the coating structure decreased, and the dye particles were easy to fall off during the friction process. Especially under the condition of wet rubbing, due to insufficient density, moisture could penetrate into the interior of the coating, reducing the water resistance of the coating and resulting in a significant reduction in the wet rubbing color fastness. Methyl silicone oil is hydrophobic and lacks good compatibility with the PU matrix, resulting in a relatively loose structure of the coating, and water is easy to penetrate into the interior of the coating; although methyl silicone oil can improve the smoothness of the coating to a certain extent, due to its simple molecular structure, the film layer formed on the coating surface is relatively thin, and the binding force with the matrix is insufficient, resulting in a less soft and smooth hand feeling.

[0088] Application Example 5 used the cover paste of Comparative Example 2. During the preparation of the PU matte emulsion, 3-aminopropyltrimethoxysilane was not added; Application Example 7 used the cover paste of Comparative Example 4 and ordinary methyl silicone oil; the properties of the prepared fabric samples were all reduced to varying degrees.

[0089] In Application Example 6, the cover paste of Comparative Example 3 was used. The dosage of 3-aminopropyltrimethoxysilane in the preparation of the PU matte emulsion was 1.5% of isophorone diisocyanate. Excessive 3-aminopropyltrimethoxysilane would increase the cross-linking density of the polyurethane, reduce the flexibility between polymer chains, cause the coating to become harder and more brittle, and thus lose its softness.

[0090] In Application Example 8, the cover paste of Comparative Example 5 was used, and the silicone oil was amino-modified silicone oil. The amino group in the amino-modified silicone oil enhanced the chemical reactivity with the coating matrix, but the overall lubricating ability was weak, the hydrophilicity was significantly insufficient, the water resistance of the coating was reduced, and the friction coefficient on the coating surface was relatively high, manifested as a decrease in the wet rubbing color fastness. Due to the lack of the flexibility and smoothness effects of the polyether chain in the amino-modified silicone oil, the hand feeling on the coating surface was relatively dry.

[0091] In Application Example 9, the cover paste of Comparative Example 6 was used, and the silicone oil was polyether-modified silicone oil. The main advantage of the polyether-modified silicone oil lies in its excellent lubricity and flexibility. Therefore, the hand feeling of Comparative Example 6 was better and the coating surface was smoother. However, due to the lack of support from the amino block, its lubricating effect could not be fully converted into an improvement in color fastness and abrasion resistance, manifested as more dye shedding during the friction process and still a relatively low wet rubbing color fastness.

[0092] Finally, it should be noted that the above-described embodiments merely represent several implementation manners of the present invention and are not intended to limit the present invention. For those of ordinary skill in the art, any modifications, equivalent substitutions, improvements, etc. made without departing from the concept of the present invention shall be included within the protection scope of the present invention. Therefore, the protection scope of this invention patent shall be subject to the appended claims.

Claims

1. An environmentally friendly water-based skin-friendly covering paste with the effect of eliminating release paper, characterized in that, By weight, it consists of the following components: PU matte emulsion: 60 - 73 parts, water: 2 - 7 parts, dispersant: 0.1 - 1 part, humectant: 5 - 8 parts, silicone oil: 17 - 23 parts, emulsifier: 0.5 - 2 parts, thickener: 1 - 5 parts; The preparation of the PU matte emulsion specifically includes the following operations: Under a nitrogen atmosphere, isophorone diisocyanate, polypropylene glycol, and dimethylolpropionic acid are added to a reactor, and the temperature is raised to 90 °C and stirred for 3 h. After the reaction is completed, it is cooled to room temperature to obtain a polyurethane prepolymer; Triethylamine and 3 - aminopropyltrimethoxysilane as a salt - forming agent are added to the polyurethane prepolymer, stirred for 30 min, and then water is added and emulsified at high speed for 1 h. The organic solvent is removed under reduced pressure to obtain the PU matte emulsion; The dosage of 3 - aminopropyltrimethoxysilane is 0.2 - 0.8% of isophorone diisocyanate; The silicone oil is polyether - modified amino - block silicone oil.

2. The environmentally friendly water-based skin-friendly covering paste with the effect of eliminating the need for release paper according to claim 1, characterized in that, The molecular weight of polypropylene glycol is 1000 - 3000.

3. The environmentally friendly water-based skin-friendly covering paste with the effect of eliminating release paper according to claim 1, characterized in that, The solid content of the PU matte emulsion is 40 ± 1%.

4. The environmentally friendly water-based skin-friendly covering paste with the effect of eliminating release paper according to claim 1, characterized in that, The PU matte emulsion also includes a matting agent, and the matting agent is any one of silica or wax - like particles. The dosage of the matting agent accounts for 1 - 3% of the mass of the PU matte emulsion.

5. The environmentally friendly water-based skin-friendly covering paste with the effect of eliminating release paper according to claim 1, wherein The dispersant is polyvinyl alcohol; The humectant is one or several of ethylene glycol, propylene glycol, or glycerol; The emulsifier is one or more of sodium dodecylbenzenesulfonate, Tween 80, or sodium dodecyl alcohol polyoxyethylene ether sulfate; The thickener is Rheovis PU 1191.

6. A preparation method of an environmentally friendly water-based skin-friendly covering paste with the effect of eliminating release paper as described in any one of claims 1-5, characterized in that, It includes the following steps: (1) Put the PU matte emulsion and water into a dispersion tank, start the stirrer, and stir evenly to obtain mixture A; (2) Continuously add the dispersant, humectant, and emulsifier to mixture A, disperse for 3 - 5 min, and then add the silicone oil and disperse for 20 - 30 min to obtain mixture B; (3) Adjust the viscosity of mixture B with the thickener, filter, and package to obtain an aqueous skin - covering paste with a non - release paper effect.

7. The preparation method of the environmentally friendly water-based skin-friendly covering paste with the effect of eliminating release paper according to claim 6, characterized in that In step (3), the viscosity of mixture B is adjusted to 50,000 - 70,000 Pa·S.

8. Application of an environment-friendly water-based skin-friendly covering paste with the effect of eliminating release paper as described in any one of claims 1-5, characterized in that, The specific operation is: Mix the environmentally friendly aqueous skin - feeling covering paste with a non - release paper effect evenly with a cross - linking aid, cover it on the printed machine - printed rubber paste 2 times, let it stand overnight, and overheat at 120 °C for 2 minutes.

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