A highly weather-resistant color label printing process

Abstract

This application relates to the field of packaging coating technology, and in particular to a high weather-resistant color label printing process; the color label printing process includes: mixing colored inks and adhesives to obtain composite inks; performing plasma treatment on the surface of packaging materials to obtain a pretreated surface; spraying titanium dioxide powder onto the pretreated surface, followed by printing the composite inks, repeating multiple times to obtain a composite color layer; covering the surface of the composite color layer with a waterproof film, and performing photocuring under ultraviolet light, followed by hot pressing to obtain the color label; the adhesives include: photoinitiator, polyamide resin, carboxymethyl cellulose, and sodium silicate; through the designed composite ink, a three-layer structure of "waterproof film - composite color layer - packaging material" can be formed, which not only makes the waterproof film and composite color layer firmly bonded, but also forms a dense structure, avoiding the erosion of water and acidic environments, and without the participation of harmful substances, making it greener and healthier.

Description

Technical Field

[0001] This application relates to the field of packaging coating technology, and in particular to a high weather-resistant color label printing process. Background Technology

[0002] With the gradual prosperity of the commodity industry, various packaging materials are used. In order to make the packaging materials more visually appealing and distinctive, colored inks are generally used for printing or spraying to form different product logos or markings. Currently, there are two types of color marking printing: one is to use colored inks as the main medium and print them onto the packaging materials, and the other is to use laser etching, which uses different media to cause an oxidation reaction on the material surface to form different colors. However, since laser marking is generally used for packaging materials with higher hardness, such as steel or stone, it is difficult to apply to softer plastic or paper packaging. Therefore, most of the printing is still done using colored inks.

[0003] However, current color ink printing generally uses multi-layer printing, where color layers are overlapped to form a composite color layer. The lifespan of color ink depends on the bonding strength of each color layer. To ensure the durability of the color, sizing agents or adhesives are generally used between the color layers to make them bond firmly. However, since current sizing agents contain a large amount of benzene or phenol impurities, which can affect human health, manufacturers generally use high-pressure lamination or high-temperature catalysis to reduce the accumulation of harmful substances in order to avoid the use of harmful substances.

[0004] However, the above methods reduce the degree of adhesive bonding, making it difficult for the printed color labels to last. At the same time, the components of color ink are mainly pigments and glues, which are easily oxidized and faded in atmospheric environments or affected by harsh weather such as acid rain. Therefore, how to provide a highly weather-resistant color label printing process that allows the color labels to last a long time with low levels of harmful substances is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] This application provides a highly weather-resistant color label printing process to solve the technical problems of excessive harmful substances and poor weather resistance in the adhesives used for color label printing in the prior art.

[0006] In a first aspect, this application provides a high weather-resistant color label printing process, the color label printing process comprising:

[0007] By mixing colored inks and adhesives, composite inks are obtained;

[0008] The surface of the packaging material is subjected to plasma treatment to obtain a pretreated surface;

[0009] Titanium dioxide powder is sprayed onto the pretreated surface, followed by printing with composite ink. This process is repeated multiple times to obtain a composite color layer.

[0010] A waterproof film is used to cover the surface of the composite color layer, which is then photocured under ultraviolet light and hot-pressed to obtain the color label.

[0011] The adhesive, by weight, comprises: photoinitiator: 25-35 parts, polyamide resin: 15-25 parts, carboxymethyl cellulose: 5-10 parts, and sodium silicate: 5-10 parts.

[0012] Optionally, the photoinitiator includes 2-hydroxy-2-methyl-1-(4-methoxy)phenyl-1-propanone and / or 2-hydroxy-2-methyl-1-(4-hydroxyethoxy)phenyl-1-propanone.

[0013] Optionally, the titanium dioxide powder includes a first particle titanium powder and a second particle titanium powder, wherein the particle size of the first particle titanium powder is 10nm to 20nm, and the particle size of the second particle titanium powder is 20nm to 35nm.

[0014] Optionally, the wavelength of the ultraviolet light used for photocuring is 370nm to 380nm; the photocuring time is 25s to 35s.

[0015] Optionally, the air velocity of the plasma treatment is 10cm / s to 15cm / s, and the distance between the plasma treatment nozzle and the packaging material is 15mm to 25mm.

[0016] Optionally, the plasma treatment time is 1 min to 5 min.

[0017] Optionally, the frequency of the plasma treatment is 15kHz to 25kHz, and the power of the plasma treatment is ≥1000W.

[0018] Optionally, the waterproof film includes at least one of PE film, PVC film and PET film.

[0019] Optionally, the hot pressing temperature is 120℃~130℃.

[0020] Optionally, the pressure of the hot pressing is 15 kPa to 20 kPa.

[0021] The technical solutions provided in this application have the following advantages compared with the prior art:

[0022] This application provides a high-weather-resistant color label printing process. By plasma treating the packaging material to be printed, the surface roughness of the packaging material is increased, and excess impurities are removed, facilitating the stable presence of titanium dioxide powder on the packaging material. Then, a composite ink containing a special adhesive and colored ink is printed. The specific adhesive formulation contains a photoinitiator, which, along with titanium dioxide, can be photocured under ultraviolet light to obtain a complex network structure. Simultaneously, polyamide resin is introduced to improve the stability of the formed network structure, thereby increasing its strength. Finally, an aqueous solution of sodium silicate formed from sodium silicate and the colored ink is used to rapidly form... The adhesive is formed into a gel and cured into a complex network structure. Carboxymethyl cellulose is then used to increase the viscosity of the adhesive, which enables a strong bond between the subsequent waterproof film and the composite color layer. Finally, photocuring fixes the colored ink in the complex network structure, while simultaneously ensuring a stable bond between the waterproof film and the composite color layer. Through the designed three-layer structure of "waterproof film - composite color layer - packaging material", the waterproof film can initially block moisture and acid and alkali components, improving the weather resistance of the label. At the same time, the composite color layer does not use harmful components such as benzene and formaldehyde, making it harmless overall. Furthermore, the overall structure is stable after the adhesive layer is cured, which can isolate the colored ink from contact with air or acid rain, further improving the weather resistance of the label. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic flowchart of the high weather-resistant color label printing process provided in the embodiments of this application. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0028] like Figure 1 As shown in the embodiment of this application, a high weather-resistant color label printing process is provided, the color label printing process including:

[0029] S1. Mix colored inks and adhesives to obtain composite inks;

[0030] S2. Plasma treatment is applied to the surface of the packaging material to obtain a pretreated surface;

[0031] S3. Spray titanium dioxide powder onto the pretreated surface, and then print composite ink. Repeat this process multiple times to obtain a composite color layer.

[0032] S4. A waterproof film is used to cover the surface of the composite color layer, and then it is cured under ultraviolet light and hot-pressed to obtain the color label;

[0033] The adhesive, by weight, comprises: photoinitiator: 25-35 parts, polyamide resin: 15-25 parts, carboxymethyl cellulose: 5-10 parts, and sodium silicate: 5-10 parts.

[0034] In this embodiment, the specific weight fraction of the photoinitiator is controlled. By introducing the photoinitiator, it can undergo a photocuring reaction with titanium dioxide powder under ultraviolet light catalysis to form a complex network structure, which can stabilize the colored ink and thus form a stable composite color layer.

[0035] Controlling the specific mass fraction of polyamide resin can increase the viscosity of the adhesive, thereby slowing down the flow rate of the composite ink and allowing the titanium dioxide powder to mix fully with the adhesive, ensuring the curing effect during the photocuring stage.

[0036] Controlling the specific mass fraction of carboxymethyl cellulose is crucial because carboxymethyl cellulose has excellent thickening, stabilizing, and dispersing effects. Therefore, carboxymethyl cellulose can improve the viscosity of adhesives and allow colored inks to mix thoroughly with the adhesives, ensuring the curing effect during the light curing stage. At the same time, it can improve the distribution of colored inks in the adhesives and ensure uniform color distribution.

[0037] Controlling the specific mass fraction of sodium silicate is crucial because sodium silicate can form an aqueous solution with the water in the colored ink. This solution can fill the complex network structure formed by the photoinitiator, improve the hydrophobicity of the complex network structure, and enhance the bonding strength between the waterproof film and the composite color layer, thereby obtaining a highly weather-resistant color label.

[0038] Packaging materials can include rigid plastic packaging, cardboard, and metal packaging materials.

[0039] In some alternative embodiments, the photoinitiator includes 2-hydroxy-2-methyl-1-(4-methoxy)phenyl-1-propanone and / or 2-hydroxy-2-methyl-1-(4-hydroxyethoxy)phenyl-1-propanone.

[0040] In this embodiment, ketone photoinitiators are used. On the one hand, the viscosity of ketone photoinitiators meets the requirements of adhesives. On the other hand, ketone photoinitiators have little impact on color, which can make the color of colored inks accurate.

[0041] In some optional embodiments, the titanium dioxide powder includes a first particle titanium powder and a second particle titanium powder, wherein the particle size of the first particle titanium powder is 10 nm to 20 nm, and the particle size of the second particle titanium powder is 20 nm to 35 nm.

[0042] In this embodiment, controlling the specific particle size distribution of titanium dioxide powder allows for a height difference between the first and second titanium dioxide particles, enabling the adhesive to quickly diffuse onto the packaging material. This ensures sufficient light-curing coverage and also increases the light-curing speed in different areas through the use of titanium dioxide particles of varying sizes, allowing the waterproof film to be quickly bonded to the composite color layer. Furthermore, the use of nano-sized titanium dioxide powder avoids its covering effect on the colored inks, ensuring uniform color development. The white effect of the nano-sized titanium dioxide powder also enhances the color difference of the colored inks, making the colors more vibrant and improving the color rendering of the label.

[0043] In some optional embodiments, the wavelength of the ultraviolet light used for photocuring is 370nm to 380nm; and the photocuring time is 25s to 35s.

[0044] In the embodiments of this application, controlling the specific parameters of photocuring can ensure that the photocuring reaction between titanium dioxide powder and photoinitiator is complete and forms a sufficiently complex network structure.

[0045] In some optional embodiments, the air velocity of the plasma treatment is 10 cm / s to 15 cm / s, and the distance between the plasma treatment nozzle and the packaging material is 15 mm to 25 mm.

[0046] In this embodiment, by controlling the wind speed and distance of the plasma treatment, the surface roughness of the packaging material can be improved without damaging it. At the same time, the high-energy plasma can remove oil, moisture and other impurities from the packaging material, allowing the packaging material to better bond with the composite ink and ensuring the bonding strength between the packaging material and the composite color layer, thereby obtaining a stable color label.

[0047] In some optional embodiments, the plasma treatment time is 1 min to 5 min.

[0048] In this embodiment, controlling the specific plasma treatment time can ensure that the surface of the packaging material has sufficient roughness after plasma treatment, while allowing the packaging material to better bond with the composite ink, ensuring the bonding strength between the packaging material and the composite color layer, thereby obtaining a stable color label.

[0049] In some optional embodiments, the frequency of the plasma treatment is 15kHz to 25kHz, and the power of the plasma treatment is ≥1000W.

[0050] In this embodiment, controlling the specific frequency and power of the plasma treatment can ensure that the plasma used in the plasma treatment has sufficient energy, thereby making the surface of the packaging material sufficiently rough and effectively removing impurities from the surface of the packaging material.

[0051] In some alternative embodiments, the waterproof film includes at least one of PE film, PVC film and PET film.

[0052] In this embodiment of the application, controlling the specific type of waterproof film can effectively improve the waterproofness and weather resistance of the waterproof film, thereby improving the weather resistance of the color label.

[0053] In some alternative embodiments, the hot pressing temperature is 120°C to 130°C.

[0054] In some alternative embodiments, the pressure of the hot pressing is 15 kPa to 20 kPa.

[0055] In this embodiment, controlling the specific temperature and pressure of hot pressing allows the waterproof film to bond stably with the packaging material, while also enabling the adhesive components in the composite ink to cure in advance, facilitating the formation of a composite color layer in the subsequent photocuring stage and resulting in a stable color label product.

[0056] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0057] Example 1

[0058] like Figure 1 As shown, a high weather-resistant color label printing process includes:

[0059] S1. Mix colored inks and adhesives to obtain composite inks;

[0060] S2. Plasma treatment is applied to the surface of the packaging material to obtain a pretreated surface;

[0061] S3. Spray titanium dioxide powder onto the pretreated surface, then print composite ink, repeating multiple times to obtain a composite color layer;

[0062] S4. A waterproof film is used to cover the surface of the composite color layer, and it is then cured under ultraviolet light and hot-pressed to obtain the color label;

[0063] The adhesive, by weight, includes: photoinitiator: 30 parts, polyamide resin: 20 parts, carboxymethyl cellulose: 7 parts, and sodium silicate: 8 parts.

[0064] The photoinitiator is 2-hydroxy-2-methyl-1-(4-methoxy)phenyl-1-propanone.

[0065] The wavelength of the ultraviolet light used for photocuring is 375nm; the photocuring time is 30s.

[0066] The air velocity for plasma treatment is 13 cm / s, and the distance between the plasma nozzle and the packaging material is 20 mm.

[0067] The plasma treatment time is 4 minutes.

[0068] The plasma processing frequency is 20kHz, and the plasma processing power is 1100W.

[0069] The waterproof membrane is a PE film.

[0070] The hot pressing temperature is 125℃.

[0071] The pressure for hot pressing is 17 kPa.

[0072] Example 2

[0073] Comparing Example 2 with Example 1, the difference between Example 2 and Example 1 is as follows:

[0074] By weight, the adhesive comprises: photoinitiator: 25 parts, polyamide resin: 15 parts, carboxymethyl cellulose: 5 parts, sodium silicate: 5 parts.

[0075] The photoinitiator is 2-hydroxy-2-methyl-1-(4-hydroxyethoxy)phenyl-1-propanone.

[0076] Example 3

[0077] Comparing Example 3 with Example 1, the difference between Example 3 and Example 1 is as follows:

[0078] By weight, the adhesive comprises: photoinitiator: 35 parts, polyamide resin: 25 parts, carboxymethyl cellulose: 10 parts, sodium silicate: 10 parts.

[0079] The photoinitiator is 2-hydroxy-2-methyl-1-(4-methoxy)phenyl-1-propanone.

[0080] Example 4

[0081] Comparing Example 4 with Example 1, the difference between Example 4 and Example 1 is as follows:

[0082] The wavelength of the ultraviolet light used for photocuring is 370nm; the photocuring time is 25s.

[0083] The air velocity for plasma treatment is 10 cm / s, and the distance between the plasma nozzle and the packaging material is 15 mm.

[0084] The plasma treatment time is 1 minute.

[0085] The plasma processing frequency is 15kHz, and the plasma processing power is 1000W.

[0086] The waterproof membrane is a PVC film.

[0087] The hot pressing temperature is 120℃.

[0088] The pressure for hot pressing is 15 kPa.

[0089] Example 5

[0090] Comparing Example 5 with Example 1, the difference between Example 5 and Example 1 is as follows:

[0091] The wavelength of the ultraviolet light used for photocuring is 380nm; the photocuring time is 35s.

[0092] The air velocity for plasma treatment is 15 cm / s, and the distance between the plasma nozzle and the packaging material is 25 mm.

[0093] The plasma treatment time is 5 minutes.

[0094] The plasma processing frequency is 25kHz, and the plasma processing power is 1200W.

[0095] The waterproof film is a PET film.

[0096] The hot pressing temperature is 130℃.

[0097] The pressure for hot pressing is 20 kPa.

[0098] Comparative Example 1

[0099] Comparative Example 1 and Example 1 will be compared. The difference between Comparative Example 1 and Example 1 is as follows:

[0100] No photoinitiator or titanium dioxide powder was introduced; otherwise, it was the same as in Comparative Example 1.

[0101] Comparative Example 2

[0102] Comparative Example 2 and Example 1 will be compared. The difference between Comparative Example 2 and Example 1 is as follows:

[0103] Polyamide resin is not introduced.

[0104] Comparative Example 3

[0105] Comparative Example 3 and Example 1 will be compared. The difference between Comparative Example 3 and Example 1 is as follows:

[0106] Carboxymethyl cellulose is not introduced.

[0107] Comparative Example 4

[0108] Comparative Example 4 and Example 1 will be compared. The difference between Comparative Example 4 and Example 1 is as follows:

[0109] Sodium silicate is not introduced.

[0110] Relevant experimental and effect data:

[0111] The color label products obtained in Examples 1-5 and Comparative Examples 1-4 were subjected to performance tests. Among them, a 15-day decolorization verification test was conducted on the color label products in a humid environment with a humidity of 95% and an oxygen content of 40%. Acid resistance tests were conducted in an environment with a pH of 2.0 and a humidity of 96% to examine the color removal time. Both tests were conducted in a closed environment with a wind speed of 8.5 m / s to 10.5 m / s. The results are shown in Table 1.

[0112] Table 1. Results of color fading verification and acid resistance test for each color label product.

[0113]

[0114] As shown in Table 1:

[0115] The color label printing process provided in this application introduces titanium dioxide and a photoinitiator for photocuring, and together with other components of the adhesive, forms a three-layer structure of "waterproof film - composite color layer - packaging material". This not only makes the waterproof film and composite color layer firmly bonded, but also forms a dense structure to avoid erosion by water and acidic environments.

[0116] One or more technical solutions in the embodiments of this application have at least the following technical effects or advantages:

[0117] (1) The high weather-resistant color label printing process provided in this application embodiment uses a designed adhesive and photocuring with titanium dioxide powder and photoinitiator to not only completely cure the composite color layer and form a complex network structure with protective effect, but also improve the dispersion of color ink through polyamide resin, carboxymethyl cellulose and sodium silicate in the adhesive and make the color ink exist stably in the network structure. In this way, the color ink can be isolated from the air and avoid the invasion of moisture and acid rain in the air. Since the adhesive used does not contain harmful substances, the weather resistance of the color label can be improved under the premise of low harmful substances, so that the color label can be preserved for a long time.

[0118] (2) The high weather-resistant color label printing process provided in this application embodiment, due to the introduction of titanium dioxide powder, can not only participate in the photocuring reaction, avoiding the use of harmful substances as solvents in adhesives, but also utilize its own metallic hue to improve the vividness of the color and improve the color rendering of the color label.

[0119] (3) The high weather-resistant color label printing process provided in this application embodiment only needs to be cured under ultraviolet light and then only needs to be hot-pressed. Therefore, it can effectively save energy and reduce production costs compared with the existing color label production process.

[0120] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0121] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in the description of this application, terms such as "comprising" and "including" mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.

[0122] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A highly weather-resistant color label printing process, characterized in that, The color label printing process includes: By mixing colored inks and adhesives, composite inks are obtained; The surface of the packaging material is subjected to plasma treatment to obtain a pretreated surface; Titanium dioxide powder is sprayed onto the pretreated surface, followed by printing with composite ink. This process is repeated multiple times to obtain a composite color layer. A waterproof film is used to cover the surface of the composite color layer, which is then photocured under ultraviolet light and hot-pressed to obtain the color label. The adhesive, by weight, comprises: photoinitiator: 25-35 parts, polyamide resin: 15-25 parts, carboxymethyl cellulose: 5-10 parts, and sodium silicate: 5-10 parts. The photoinitiator includes 2-hydroxy-2-methyl-1-(4-methoxy)phenyl-1-propanone and / or 2-hydroxy-2-methyl-1-(4-hydroxyethoxy)phenyl-1-propanone; The titanium dioxide powder includes a first particle titanium powder and a second particle titanium powder, wherein the particle size of the first particle titanium powder is 10nm to 20nm, and the particle size of the second particle titanium powder is 20nm to 35nm. The wavelength of the ultraviolet light used for photocuring is 370nm to 380nm; the photocuring time is 25s to 35s.

2. The color label printing process according to claim 1, characterized in that, The air velocity of the plasma treatment is 10 cm / s to 15 cm / s, and the distance between the plasma treatment nozzle and the packaging material is 15 mm to 25 mm.

3. The color label printing process according to claim 2, characterized in that, The plasma treatment time is 1 min to 5 min.

4. The color label printing process according to claim 3, characterized in that, The frequency of the plasma treatment is 15kHz to 25kHz, and the power of the plasma treatment is ≥1000W.

5. The color label printing process according to claim 1, characterized in that, The waterproof film includes at least one of PE film, PVC film and PET film.

6. The color label printing process according to claim 1, characterized in that, The hot pressing temperature is 120℃~130℃.

7. The color label printing process according to claim 1, characterized in that, The pressure of the hot pressing is 15 kPa to 20 kPa.

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