A photochromic waterless printing paste and its preparation method and application

Abstract

The present invention discloses a photochromic waterless printing paste and a preparation method and application thereof, wherein the photochromic waterless printing paste comprises a photochromic compound, a solvent and an adhesive; wherein the mass ratio of the photochromic compound, the solvent and the adhesive is (1-5):(95-99):(200-300), the solvent is chloroform, and the adhesive is an aliphatic polyurethane of a polycarbonate system. The photochromic waterless printing paste provided by the present invention is a photochromic waterless printing paste with strong durability, fast response, anhydrous environmental protection and excellent performance, which effectively makes up for the deficiencies in the prior art and has extremely high application value and promotion potential.

Description

Technical Field

[0001] The invention relates to the field of new materials, and in particular to a photochromic waterless printing paste and a preparation method and application thereof. Background Art

[0002] With the development of society, the advancement of science and technology, and the improvement of people's consumption capacity, people's expectations for textiles are not only to have the traditional wearing function, but also to have some unique intelligent response performance. "Intelligent Textile" usually refers to a new type of textile that runs through multidisciplinary integrated technologies such as textiles, electronics, information, biology, medicine, and new energy, and can sense changes in human body and environmental signals and actively respond through feedback mechanisms, while retaining the inherent style and technical characteristics of traditional textiles. Photochromic textiles are a type of intelligent textiles that can change into different colors under the stimulation of light, and have attracted increasing attention from researchers in related fields.

[0003] With the continuous development of smart textiles, photochromic materials have received extensive attention in the fields of smart textiles, fashion design and functional fabric development due to their unique reversible color-changing properties. Photochromic materials can undergo rapid color changes under light stimulation and restore to their original state after the light source is removed, giving textiles a variety of additional functions such as dynamic display, decoration, beautification and environmental monitoring. However, the formulation and application process of printing paste in the prior art have certain limitations in achieving photochromic properties:

[0004] 1. Disadvantages of aqueous printing paste: Currently, most printing pastes use aqueous systems as carriers, but the presence of water may significantly affect the stability of photochromic compounds, causing them to decompose, fail or deteriorate during long-term use or storage. In addition, water as a medium may also cause uneven dispersion and poor penetration between the compound and the substrate, thereby affecting the color change efficiency and uniformity of the finished textile product. More importantly, the applicability of aqueous systems is limited under certain special process conditions (such as low humidity environments), which limits the promotion and application scope of the technology.

[0005] 2. Inherent limitations of photochromic compounds: Photochromic compounds are generally sensitive and unstable, and are easily affected by hot and humid environments, ultraviolet rays, and the structural characteristics of the material itself, which reduces the response speed and reversibility to light stimulation during repeated color changes. This poses a challenge to the preparation of durable and efficient photochromic textiles in practical applications. Especially when printing on the surface of fabrics, how to improve the durability and fatigue resistance of the material while taking into account the uniformity of performance is an urgent problem to be solved.

[0006] 3. Inadequate coating protection technology: In traditional coating protection processes, polymer coating agents usually have limited protective effects on photochromic materials. Not only may they react adversely with photochromic agents, but they may also reduce the material response sensitivity in order to improve firmness, making it difficult to meet high-performance requirements. At the same time, the existing common coating processes perform poorly in terms of water fastness and UV resistance, which significantly limits the development potential of photochromic textiles in outdoor areas and high-frequency application scenarios. Summary of the invention

[0007] In order to overcome the deficiencies in the prior art, the present invention provides a photochromic waterless printing paste with strong durability, fast response, anhydrous environmental protection and excellent performance, which effectively makes up for the deficiencies in the prior art and has extremely high application value and promotion potential.

[0008] In order to achieve the above-mentioned invention object, the technical solution adopted to solve the technical problem is as follows:

[0009] The first aspect of the present invention provides a photochromic waterless printing paste. 1. The photochromic waterless printing paste comprises a photochromic compound, a solvent and an adhesive; wherein the mass ratio of the photochromic compound, the solvent and the adhesive is (1-5):(95-99):(200-300), the solvent is chloroform, and the adhesive is an aliphatic polyurethane of a polycarbonate system.

[0010] In one embodiment of the present invention, the photochromic compound is a naphthopyran photochromic material.

[0011] In one embodiment of the present invention, the brand of the photochromic compound is at least one of PD Red Ruby 12, PDOrange 23, PD Roland Purple 72, PD Yellow 32, and PD SeaBlue 53.

[0012] In one embodiment of the present invention, the adhesive is PU207.

[0013] The second aspect of the present invention provides a method for preparing the above-mentioned photochromic waterless printing paste, comprising the following steps: adding a photochromic compound to chloroform and stirring evenly, then adding a binder and stirring evenly to obtain the photochromic waterless printing paste.

[0014] The third aspect of the present invention provides the application of the above-mentioned photochromic waterless printing paste in a fabric printing process, comprising the following steps: printing - drying - heat setting; wherein the drying specifically comprises: after drying at 80°C, covering the surface with an aliphatic polyurethane of a polycarbonate system and then heat setting.

[0015] In one embodiment of the present invention, the heat setting is performed by baking, the baking temperature is 100° C., and the baking time is 5 minutes.

[0016] In one embodiment of the present invention, the drying time is 3 minutes.

[0017] In one embodiment of the present invention, after drying at 80° C. for 3 minutes, PU207 is used to cover the surface and then heat setting is performed.

[0018] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art:

[0019] 1. Existing printing pastes are generally water-containing systems, and the presence of water not only affects the stability of photochromic compounds, but may also lead to problems such as uneven dye diffusion and decreased color change performance. The photochromic waterless printing paste provided by the present invention adopts an anhydrous formula and uses chloroform as a solvent, which completely avoids the influence of water on the stability of photochromic compounds and printing effects, thereby significantly improving product quality and application reliability.

[0020] 2. In the photochromic waterless printing paste provided by the present invention, PU206 adhesive is used, which is combined with chloroform solvent to form a specific chemical environment, which effectively improves the solubility and dispersion stability of the photochromic compound in the waterless system. This design not only meets the demand for water-free printing, but also broadens the application scenarios of printing paste in extreme environments, such as special production and use scenarios in high dryness, low humidity areas, etc.

[0021] 3. In the present invention, by optimizing the ratio of photochromic compounds, solvents and adhesives in specific proportions, the obtained photochromic textiles can respond quickly under light stimulation and achieve maximum color change, and this color change has excellent reversible characteristics and can be cyclically changed without obvious optical fatigue. This provides significant technical advantages for the production of high dynamic display needs and fashionable functional textiles.

[0022] 4. The application of the photochromic waterless printing paste provided by the present invention in the fabric printing process comprises the following steps: printing - drying - heat setting; wherein the drying specifically comprises: after drying at 80°C, covering the surface with aliphatic polyurethane of a polycarbonate system and then heat setting. The photochromic layer is effectively fixed by the aliphatic polyurethane covering process of the polycarbonate system, which significantly improves the performance stability of the final textile under multiple washing conditions and prolongs the service life of the product.

[0023] 5. The application of the photochromic waterless printing paste provided by the present invention in the fabric printing process, the obtained textiles have excellent UV resistance, and can maintain the photochromic function without attenuation or deterioration under long-term sunlight conditions, providing good protection for the outdoor application of photochromic textiles.

[0024] 6. In the application of the photochromic waterless printing paste provided by the present invention in the fabric printing process, the bonding force between the photochromic coating and the substrate is further enhanced through the fine control of the drying and heat setting processes (such as using an aliphatic polyurethane cover of a polycarbonate system after drying at 80°C), making the coating more uniform and firm, and being able to give full play to the performance potential of the photochromic paste.

[0025] 7. The present invention provides innovative ideas for the design and preparation of new photochromic textiles. The resulting products not only meet functional requirements, but also take into account durability and aesthetics, and are suitable for multiple fields such as clothing, interior decoration materials and high-end functional fabrics. At the same time, its water-free design lays the foundation for environmentally friendly manufacturing processes and has positive significance in energy conservation and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0027] Figure 1 This is a photograph of the fabric printing sample obtained in Application Example 3 under indoor light;

[0028] Figure 2 This is a photograph of the fabric printing sample obtained in Application Example 3 under sunlight;

[0029] Figure 3 This is a photograph of the fabric printing sample obtained in Application Example 3 after being exposed to sunlight for one week;

[0030] Figure 4 This is a photograph of the fabric printing sample obtained in Application Example 1 under indoor light;

[0031] Figure 5 This is a photograph of the fabric printing sample obtained in Application Example 1 under sunlight;

[0032] Figure 6 This is a photograph of the fabric printing sample obtained in Application Example 2 under indoor light;

[0033] Figure 7 This is a photograph of the fabric printing sample obtained in Application Example 2 under sunlight;

[0034] Figure 8 This is a photograph of the fabric printing sample obtained in Application Example 2 after 20 cycles of sunlight discoloration and fading. DETAILED DESCRIPTION

[0035] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Example 1

[0037] This embodiment provides a photochromic waterless printing paste, which includes a photochromic compound, a solvent and an adhesive.

[0038] Wherein, the solvent in this embodiment is chloroform.

[0039] The mass ratio of the photochromic compound, the solvent and the adhesive in this embodiment is 4:96:210, the solvent is chloroform, and the adhesive is PU206.

[0040] The brand of the photochromic compound in this embodiment is PD Red Ruby 12.

[0041] The preparation steps of the photochromic waterless printing paste in this embodiment are as follows: adding the photochromic compound to chloroform and stirring evenly, then adding the binder and stirring evenly to obtain the photochromic waterless printing paste.

[0042] Example 2

[0043] This embodiment provides a photochromic waterless printing paste. The photochromic waterless printing paste in this embodiment is different from that in Embodiment 1 only in that the brand of the photochromic compound in this embodiment is PD Orange 23.

[0044] Example 3

[0045] This embodiment provides a photochromic waterless printing paste. The photochromic waterless printing paste in this embodiment is different from that in Embodiment 1 only in that the brand of the photochromic compound in this embodiment is PD Roland Purple 72.

[0046] Example 4

[0047] This embodiment provides a photochromic waterless printing paste. The photochromic waterless printing paste in this embodiment is different from that in Embodiment 1 only in that the brand of the photochromic compound in this embodiment is PD Yellow 32.

[0048] Example 5

[0049] This embodiment provides a photochromic waterless printing paste. The photochromic waterless printing paste in this embodiment is different from that in Embodiment 1 only in that the brand of the photochromic compound in this embodiment is PD Sea Blue 53.

[0050] Example 6

[0051] This embodiment provides a photochromic waterless printing paste. The photochromic waterless printing paste in this embodiment is different from that in Embodiment 2 only in that the mass ratio of the photochromic compound, the solvent and the adhesive in this embodiment is 2:96:210.

[0052] Example 7

[0053] This embodiment provides a photochromic waterless printing paste. The photochromic waterless printing paste in this embodiment is different from that in Embodiment 1 only in that the photochromic compound in this embodiment is PD Rain Blue 56.

[0054] Example 8

[0055] This embodiment provides a photochromic waterless printing paste. The photochromic waterless printing paste in this embodiment is different from that in Example 6 only in that the photochromic compound in this embodiment is PD Rain Blue 56, and the mass ratio of the photochromic compound, the solvent and the adhesive in this embodiment is 2:96:210.

[0056] Comparative Example 1

[0057] This embodiment provides a printing paste, which is different from the printing paste of Embodiment 6 only in that the printing paste of this embodiment does not contain a photochromic compound.

[0058] Application Example 1

[0059] This application example uses the photochromic waterless printing paste provided in Examples 1-2 to carry out a printing process on textiles, including the following steps: laying the selected printed fabric on a rubber pad and placing a printing screen; pouring the prepared waterless printing paste on the printing screen, scraping it back and forth twice with a rubber scraper, and then lifting the printing screen, and sending the printed fabric into an oven for drying (80°C, 3min); after rapid drying, covering the surface with aliphatic polyurethane (PU207) of a polycarbonate system, and then placing it in a shaping dryer that has been heated to 100°C for baking for 5min. After baking, the optimized printing process is completed.

[0060] After the printing process is completed, the fabric printing sample is as follows Figure 4 shown.

[0061] Application Example 2

[0062] This application example uses the photochromic waterless printing paste provided in Examples 1-5 to carry out a printing process on textiles, including the following steps: laying the selected printed fabric on a rubber pad and placing a printing screen; pouring the prepared waterless printing paste on the printing screen, scraping it back and forth twice with a rubber scraper, and then lifting the printing screen, and sending the printed fabric into an oven for drying (80°C, 3min); after rapid drying, covering the surface with aliphatic polyurethane (PU207) of a polycarbonate system, and then placing it in a shaping dryer that has been heated to 100°C for baking for 5min. After baking, the optimized printing process is completed.

[0063] After the printing process is completed, the fabric printing sample is as follows Figure 6 shown.

[0064] Application Example 3

[0065] This application example uses the photochromic waterless printing paste provided in Examples 1, 6, 7, and 8 and the printing paste provided in Comparative Example 1 to carry out a printing process on textiles. The printing process specifically includes the following steps: the selected printed fabric is laid on a rubber pad and a printing net is placed on it; the prepared waterless printing paste is poured on the printing net, and a rubber scraper is used to scrape it back and forth twice, and then the printing net is lifted, and the printed fabric is sent to an oven for drying (80°C, 3min). After the fabric is dried, it is placed in a sample setting drying machine that has been heated to 100°C and baked for 3min. After baking, the printing process is completed.

[0066] Experimental Example 1

[0067] The printed fabric obtained in Application Example 3 was irradiated with noon sunlight, and the color change and color depth before and after illumination were observed. The photochromic onset time, saturation time and recovery time were recorded, and the photochromic effects of the selected printed fabrics were compared to screen out the best fabric suitable for preparing photochromic fabrics.

[0068] Figure 1 The following is a picture of the fabric under indoor light. It can be seen that the two color-changing materials appear light red and gray. After being exposed to sunlight, the fabric immediately changes color. After about 5-10 seconds, the color becomes Figure 2 As shown in the analysis, the molecular structure of the material changes under the irradiation of sunlight / ultraviolet light, resulting in a significant change in color. After being transferred indoors, the color of the fabric gradually fades, and after 10-20 seconds, it changes to Figure 1 Color shown; Figure 1 and Figure 2 The printing pastes used from top to bottom are Comparative Example 1, Example 1, Example 6, Example 7, and Example 8.

[0069] The photochromic properties of the two color-changing materials are shown in Table 1. Their reaction times to light are different, but both have good photochromic effects, and the photochromic and fading speeds are relatively fast.

[0070] Table 1. Photochromic properties of color-changing materials

[0071]

[0072] The fabric sample was placed in sunlight for 2 minutes to fully change color, and then placed away from sunlight in a dark place to restore it to its original color. This cycle was repeated to measure the number of reversible color changes, i.e., the cycle life, to evaluate its fatigue resistance. It was found that after 30 cycles, the photochromic properties of the material did not change much, indicating that it has good fatigue resistance. Considering that textiles will be worn for a long time, the fabric sample was exposed to sunlight and found to be completely ineffective after one week. Figure 3 After analysis, it is found that although fabrics with photochromic effect can be obtained by applying color-changing materials to plain polyester or cotton fabrics using methods similar to reactive dyeing and full-material direct printing, the printing process, mainly the color paste, lacks protection for the photochromic materials, making this printing scheme unfeasible.

[0073] Experimental Example 2

[0074] Expose the printed fabrics in Application Example 1 and Application Example 2 to sunlight at noon, observe the color changes and color depth before and after illumination, record the photochromic onset time, saturation time, and recovery time, compare the photochromic effects of the selected printed fabrics, and screen out the best fabric suitable for preparing photochromic fabrics.

[0075] in, Figure 4 , Figure 5 The two colors from left to right in the figure respectively use the printing paste described in Examples 1-2.

[0076] in, Figure 6, Figure 7 , Figure 8 The five colors from left to right in the figure respectively use the printing paste described in Examples 1-5.

[0077] Figure 4 The fabric printing sample is indoor light. Figure 5 Under sunlight, it can be seen that the red color-changing material appears light red indoors. After being exposed to sunlight, the fabric immediately changes color. After being moved indoors, the color of the fabric gradually fades. The material has a good photochromic effect, and the photochromic and fading speeds are relatively fast.

[0078] Figure 6 The optimized fabric printing samples include 5 colors, effects and Figure 4 , Figure 5 The photochromic reaction of the fabric is consistent, and it changes from colorless to colored under sunlight, with uniform color development and rich color. Table 2 shows the photochromic property test of the above color-changing materials. It can be found that the initial change time of the color-changing materials is not much different, which means that the materials will change color when exposed to sunlight, and the saturation time and recovery time are significantly different, which is caused by the different groups connected to the naphthopyran molecules.

[0079] Table 2. Figure 4-Figure 7 Photochromic properties of the color-changing materials shown

[0080]

[0081]

[0082] Table 3. Figure 6-Figure 8 Photochromic fatigue properties of the photochromic materials shown

[0083]

[0084] The reversible color change times and cycle life of the optimized sample were measured to evaluate its fatigue resistance. First, the initial ultraviolet absorption spectrum of the sample was tested under green light with a wavelength of 520nm to obtain the initial absorbance value of the sample, and then the sample was irradiated under sunlight for 30 times to change color and fade indoors. The ultraviolet absorption spectrum of the sample was tested again under green light with a wavelength of 520nm. It was found that the photochromic properties of the material did not change much, indicating that it had good fatigue resistance.

[0085] On this basis, the fatigue resistance of the sample was further tested. In a UV light box simulation test, the UV wavelength was 365nm. After 10 hours of irradiation, the UV absorption spectrum of the sample was tested under green light with a wavelength of 520nm. It was found that the color dropped by about 10%.

[0086] Another sample was taken, and the color fastness to friction and washing of the discoloration sample was tested with reference to the national standards GB / T 3920-2008 and GB / T 3921-2008. The color fastness to dry friction of the discoloration sample was 4, the color fastness to wet friction was 4 to 5, and the color fastness to soap washing was 4 to 5. The color fastness of different colors was basically the same. Furthermore, after 30 standard water washings, the ultraviolet absorption spectrum of the sample was tested again under green light with a wavelength of 520nm. The washing test showed that the color change performance of the sample decreased by about 10%, and it still had obvious color changes. The anti-ultraviolet performance UPF still remained above 90, indicating that it has excellent water washing fastness and anti-ultraviolet performance. It has been verified that the printing process can protect photochromic materials, and the printing scheme is convenient and feasible.

[0087] In summary, the waterless printing paste claimed in the present invention has good light response performance, can respond to light stimulation in a short time and achieve maximum color change, and can reversibly change color multiple times, and has excellent optical fatigue performance. In addition, it has excellent water fastness and UV resistance, which provides a new idea for the design and preparation of new durable photochromic textiles.

[0088] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A photochromic waterless printing paste, characterized in that: The photochromic waterless printing paste comprises a photochromic compound, a solvent and an adhesive; wherein the mass ratio of the photochromic compound, the solvent and the adhesive is (1-5):(95-99):(200-300), the solvent is chloroform, and the adhesive is an aliphatic polyurethane of a polycarbonate system.

2. The photochromic waterless printing paste according to claim 1, characterized in that: The photochromic compound is a naphthopyran photochromic material.

3. The photochromic waterless printing paste according to claim 2, characterized in that: The brand of the photochromic compound is at least one of PD Red Ruby 12, PD Orange 23, PD Roland Purple 72, PD Yellow 32, and PD Sea Blue53.

4. The photochromic waterless printing paste according to claim 1, characterized in that: The adhesive is PU207.

5. The method for preparing the photochromic waterless printing paste according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: adding a photochromic compound into chloroform and stirring evenly, then adding an adhesive and stirring evenly to obtain a photochromic waterless printing paste.

6. Use of the photochromic waterless printing paste according to any one of claims 1 to 4 in a fabric printing process, characterized in that: The method comprises the following steps: printing - drying - heat setting; wherein the drying specifically comprises: drying at 80°C, covering the surface with aliphatic polyurethane of a polycarbonate system and then heat setting.

7. The use of the photochromic waterless printing paste according to claim 6 in a fabric printing process, characterized in that: The heat setting is carried out by baking, the baking temperature is 100°C, and the baking time is 5 minutes.

8. The use of the photochromic waterless printing paste according to claim 7 in a fabric printing process, characterized in that: The drying time is 3 minutes.

9. The use of the photochromic waterless printing paste according to claim 8 in a fabric printing process, characterized in that: After drying at 80℃ for 3 minutes, PU207 is used to cover the surface and then heat-set.

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