High-weather-resistance sunlight color-changing offset printing ink and preparation method thereof

Abstract

The invention relates to the field of color-changing ink, and particularly discloses high-weather-resistance sunlight color-changing offset ink and a preparation method thereof. Comprising the following components in parts by mass: 40-50 parts of rosin modified phenolic resin, 10-20 parts of hydroxy acrylic resin, 10-20 parts of mineral oil, 10-25 parts of photochromic pigment and 1-6 parts of auxiliaries, the photochromic pigment comprises one or more of spiropyrane and derivatives thereof, spirozine and derivatives thereof, fulgide and derivatives thereof, an azo compound and triarylmethane and derivatives thereof, and the photochromic pigment comprises one or more of 1, 2, 4-trimethyl-1, 3-pentanediol and 1, 2, 4-trimethyl-1, 3-pentanediol. According to the present invention, the high weather resistance sunlight color changing offset printing ink has advantages of good weather resistance and lasting color changing.

Description

Technical Field

[0001] The present application relates to the field of offset printing inks, and more specifically, to a highly weather-resistant daylight-changing offset printing ink and a preparation method thereof. Background Art

[0002] Offset ink is a fluid or semi-fluid substance composed of pigments, binders, fillers, and additives. The ink is evenly transferred to the printing plate via the printing press's roller transfer system. The ink is then transferred to the substrate via the rubber blanket, creating a clear image print. This print achieves high color saturation and vividness, accurately reproducing a wide range of colors. The resulting printed images are rich in color and distinct in layers, making it suitable for printing high-quality color publications and packaging products.

[0003] When an appropriate amount of photochromic pigment is added to the offset ink, when the ink is exposed to light of a specific wavelength in sunlight, the molecular structure of the pigment changes, thereby changing the color of the ink.

[0004] Commonly used photochromic inks include spiropyran, fulgide, etc., but these compounds contain many easily hydrolyzed groups. In a hot and humid environment, water molecules act as nucleophiles to attack the spirocyclic carbon atoms of spiropyran, or the anhydride bonds of fulgide to generate carboxylic acids, causing the conjugated structure to collapse and lose the color-changing core. Photochromism relies on reversible isomerization, such as spiropyran ring opening, ring closing, and azo cis-trans isomerization, but high temperature will increase the molecular kinetic energy, causing the reversible reaction to tend to a thermodynamically stable state, and even cross the activation energy barrier to cause irreversible decomposition.

[0005] To expand the application scenarios of color-shifting offset inks, higher requirements are being placed on their weather resistance. Current offset inks often add stabilizers or fillers to improve the ink's color stability. However, stabilizers have limited effectiveness, while fillers can obscure the color-shifting pigment, reducing the clarity and vividness of the ink's graphics and text, and also affecting the ink's adhesion. Therefore, providing a weather-resistant, daylight-shifting offset ink and its preparation method holds great promise. Summary of the Invention

[0006] In order to improve the weather resistance of color-changing ink, the present application provides a highly weather-resistant sunlight-changing offset printing ink and a preparation method thereof.

[0007] In a first aspect, the present application provides a highly weather-resistant sunlight-changing offset printing ink, which adopts the following technical solution: A highly weather-resistant daylight-changing offset printing ink comprises the following components in parts by weight: 40-50 parts of a rosin-modified phenolic resin, 10-20 parts of a hydroxylated acrylic resin, 10-20 parts of a mineral oil, 10-25 parts of a photochromic pigment, and 1-6 parts of an additive. The photochromic pigment comprises one or more of spiropyran and its derivatives, spirooxanes and its derivatives, fulgide and its derivatives, azo compounds, and triarylmethane and its derivatives.

[0008] By adopting the above technical solution, the rosin-modified phenolic resin has a honeycomb cross-linked network structure, the long-chain alkyl and the aromatic ring structure of phenolic form a hydrophobic barrier, reducing water penetration, the low acid value reduces the risk of hydrolysis, and the hydrophobicity is also compatible with the hydrophobic groups of pigments such as spiropyran, and the natural antioxidant components such as rosin acid in rosin can delay the oxidation of the system. Through the limitation of quality, the cross-linked network is suitable for the ink formula of this application, the photochromic pigment can be more stably dispersed in the system, the carboxyl acrylic resin has good transparency and is suitable for the use of photochromic pigments, the acrylic chain segment gives the material flexibility, reduces the rapid deterioration of quality caused by crack expansion due to thermal stress, and the hydroxyl group can also react with the epoxy group of spiropyran to enhance the interfacial bonding force and reduce the migration loss of the color-changing molecules in the solid matrix. At the same time, the open-ring MC of spiropyran will not be restricted in movement, and the color development efficiency is long-lasting and stable. Under the joint action of rosin-modified phenolic resin and hydroxyl acrylic resin, the rigid network of phenolic resin and the flexible chain segments of acrylic resin form an interpenetrating structure, which inhibits volume expansion under wet and hot stress. A certain amount of mineral oil is added as a plasticizer and solvent to adjust the viscosity of the system and improve processing fluidity. Its non-polar properties can also fill the pores of the resin network, further reducing the diffusion path of water molecules and enhancing the weather resistance of the ink.

[0009] Preferably, the photochromic pigment comprises 1,4-di(oxiran-2-yl)benzene-modified spiropyran.

[0010] By adopting the above technical solution, the photochromic response speed of spiropyran is faster, the epoxy group partially opens the ring to form cross-linking points, and it is more stable in the system. At the same time, in the gaps between the stacked rosin-modified phenolic resin and the hydroxy acrylic resin, the benzene ring forms a certain steric hindrance to further fill and protect the spiropyran. The obtained 1-methoxy-2-(epoxymethoxy)benzene-modified spiropyran has more stable color-changing performance.

[0011] Preferably, the 1,4-di(oxiran-2-yl)benzene-modified spiropyran includes the following preparation steps: adding spiropyran to chloroform, adding ferric chloride, slowly adding 1,4-di(oxiran-2-yl)benzene dropwise, reacting at low temperature under an argon atmosphere, cooling, adding acetone, extracting with ethanol Soxhlet, and vacuum drying to obtain 1,4-di(oxiran-2-yl)benzene-modified spiropyran.

[0012] Preferably, the mass ratio of 1,4-di(oxirane-2-yl)benzene, spiropyran and ferric chloride is 1:0.5:(0.15-0.20).

[0013] Preferably, the temperature is 20-30° C. and the reaction time is 8-10 hours.

[0014] By adopting the above technical solution, the preparation process is relatively simple, the by-products are less, and the product stability is higher.

[0015] Preferably, the mass ratio of the rosin-modified phenolic resin, the hydroxy acrylic resin, and the photochromic pigment is 3:(1-1.1):(1.2-1.3).

[0016] By adopting the above technical solution, the cross-linking density in the system is more appropriate, which improves the stability of the photochromic pigment while not making it difficult to recover the open-ring spiropyran, and the obtained ink is stably photochromic.

[0017] Preferably, the mass ratio of rosin-modified phenolic resin, hydroxy acrylic resin and photochromic pigment is 3:1:1.3.

[0018] Preferably, the rosin-modified phenolic resin is a furanized rosin phenolic resin, and the carboxyl acrylic resin is a polyimidized carboxyl acrylic resin.

[0019] By adopting the above technical solution, the conjugated structure of the furan ring can reduce the oxidation of the resin, the imide ring of the maleimide can enhance the thermal stability of the resin, and further interpenetrate with the phenolic resin and acrylic resin of the system, reducing phase separation, extending the water and oxygen diffusion path, and making the ink more weather-resistant. At the same time, it may be that the furan ring and the imide ring form a Diels-Alder dynamic bond at this time, which not only gives the coating self-healing ability without significantly sacrificing weather resistance, but also enables the open-ring spiropyran to recover better in the dynamic bond environment, further extending the stable ink color change performance in wet, hot and oxygen environments.

[0020] In a second aspect, the present application provides a method for preparing a highly weather-resistant sunlight-chromic offset printing ink, which adopts the following technical solution: A method for preparing a highly weather-resistant daylight-changing offset printing ink comprises the following steps: weighing raw materials by mass, uniformly mixing a photochromic pigment and an additive, grinding the mixture to a fineness of less than 20 μm, and adding the remaining components to obtain the highly weather-resistant daylight-changing offset printing ink.

[0021] By adopting the above technical solution, the preparation method is simple and suitable for the ink of this application. The intrusion of water and oxygen is prolonged through the combined action of the stacked benzene rings and maleimide of rosin-modified phenolic resin, the rigid-flexible resin interpenetrating network of phenolic resin and acrylic resin, the small-volume benzene rings of 1,4-di(oxirane-2-yl)benzene-modified spiropyran, and the non-polar mineral oil filler.

[0022] In summary, this application has the following beneficial effects: 1. This application uses rosin-modified phenolic resin and hydroxyl acrylic resin to jointly construct a rigid-flexible resin interpenetrating network, and further uses the small benzene ring of 1,4-di(oxirane-2-yl)benzene-modified spiropyran and non-polar mineral oil filler to jointly extend the intrusion of water and oxygen and improve the weather resistance of the ink. 2. This application forms Diels-Alder dynamic bonds by limiting the rosin-modified phenolic resin to furanized rosin phenolic resin and the carboxyl acrylic resin to polyimidized carboxyl acrylic resin. This not only gives the coating self-healing ability without significantly sacrificing weather resistance, but also enables the open-ring spiropyran to recover better, further extending the stable ink color change performance in wet, hot, and oxygen environments. DETAILED DESCRIPTION

[0023] To further help understand the technical solution of the present invention, the following provides several specific implementation examples to describe the technical solution of the present invention in more detail. All of these described embodiments are only some embodiments of the present invention, not all. The following specific embodiments may be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments; and the reaction devices, monomer compounds, etc. involved in the following embodiments are all commercially available.

[0024] The following specific embodiments may be combined with each other, and the same or similar concepts or processes therein may not be described in detail in some embodiments.

[0025] The following examples are further explanations of the present invention, but the present invention is not limited thereto. Unless otherwise specified in the examples, the percentages are all by mass.

[0026] The model of the dispersant is TX-40; the defoamer is polyether modified silicone defoamer HY-6803.

[0027] Preparation Example Preparation Example 1: 1,4-di(oxirane-2-yl)benzene-modified spiropyran 5 g of spiropyran was added to 200 ml of chloroform, 1.8 g of ferric chloride was added, and the mixture was stirred evenly. 10 g of 1,4-di(oxiran-2-yl)benzene was slowly added dropwise over 1 hour. The mixture was reacted at 25°C under an argon atmosphere for 8 hours. The mixture was cooled, acetone was added, and the mixture was extracted with ethanol Soxhlet and dried in vacuo to obtain 1,4-di(oxiran-2-yl)benzene-modified spiropyran.

[0028] Preparation Example 2: Rosin phenolic resin Mix 10g of phenol, 8g of formaldehyde, and 5g of rosin, heat to 75°C, add 0.1g of oxalic acid catalyst, stir at 200rpm for 2 hours, heat to 100°C for dehydration until the system is transparent, cool to 50°C, add ethanol to dilute, and filter to obtain rosin phenolic resin.

[0029] Preparation Example 3: Furanized rosin phenolic resin Mix 10 g of phenol, 8 g of formaldehyde, and 5 g of rosin, heat to 75°C, add 0.1 g of oxalic acid catalyst, stir at 200 rpm for 2 hours, cool to 60°C, slowly add furan methanol dropwise, continue to react for 3 hours, heat to 100°C for dehydration until the system is transparent, cool to 50°C, add ethanol to dilute, filter, and vacuum dry to obtain furanized rosin phenolic resin.

[0030] Preparation Example 4: Carboxylic Acrylic Resin 5 g of methacrylic acid (MAA), 11 g of styrene, and 33 ml of toluene were mixed evenly, protected by nitrogen, and heated to 85°C. 8 ml of a 5 wt% toluene solution of azobisisobutyronitrile (AIBN) was added dropwise over 2 hours. The mixture was kept warm for 5 hours and cooled to 50°C. The resin solution was added dropwise to n-hexane for precipitation. After filtration, the mixture was dried under vacuum to obtain a carboxyl acrylic resin.

[0031] Preparation Example 5: Polyimidized carboxyl acrylic resin 10 g of hydroxyethyl acrylate HEA, 17 g of methyl methacrylate MMA, 3.3 g of maleimide acrylate MAA and 27 ml of butanone were mixed evenly, protected by nitrogen, heated to 70°C, and 5 ml of 10 wt% azobisisobutyronitrile AIBN butanone solution was added dropwise. The reaction was kept warm for 4 hours, cooled to room temperature, and the resin solution was dropped into n-hexane for precipitation. After filtration, it was vacuum dried to obtain a polyimidized carboxyl acrylic resin.

[0032] Preparation Example 6: 1,4-Dibenzyloxybenzene-modified spiropyran 5 g of spiropyran was added to 200 ml of chloroform, and 1.8 g of ferric chloride was added. The mixture was stirred evenly, and 10 g of 1,4-dibenzyloxybenzene was slowly added dropwise over 1 hour. The mixture was reacted at 25°C under an argon atmosphere for 8 hours. The mixture was cooled, acetone was added, and the mixture was extracted with ethanol Soxhlet and dried in vacuo to obtain 1,4-dibenzyloxybenzene-modified spiropyran. Example

[0033] Example 1 45 g of rosin-modified phenolic resin prepared in Preparation Example 2, 15 g of hydroxylated acrylic resin prepared in Preparation Example 4, 15 g of mineral oil, 15 g of spiropyran, 2 g of dispersant, and 2 g of defoaming agent.

[0034] The raw materials were weighed by mass and set aside. Spiropyran, dispersant and defoamer were mixed evenly and ground to a fineness of 20 μm. The remaining components were added and stirred at a speed of 800 r / min for 1 h. The mixture was pressure filtered to obtain a highly weather-resistant daylight-changing offset printing ink.

[0035] Example 2 45 g of rosin-modified phenolic resin prepared in Preparation Example 2, 15 g of hydroxy acrylic resin prepared in Preparation Example 4, 15 g of mineral oil, 15 g of 1,4-di(oxirane-2-yl)benzene-modified spiropyran prepared in Preparation Example 1, 2 g of dispersant, and 2 g of defoaming agent.

[0036] The raw materials were weighed by mass and set aside. Spiropyran, dispersant and defoamer were mixed evenly and ground to a fineness of 20 μm. The remaining components were added and stirred at a speed of 800 r / min for 1 h. The mixture was pressure filtered to obtain a highly weather-resistant daylight-changing offset printing ink.

[0037] Example 3 45 g of rosin-modified phenolic resin prepared in Preparation Example 2, 15 g of hydroxy acrylic resin prepared in Preparation Example 4, 15 g of mineral oil, 13 g of 1,4-di(oxirane-2-yl)benzene-modified spiropyran prepared in Preparation Example 1, 2 g of dispersant, and 2 g of defoaming agent.

[0038] The raw materials were weighed by mass and set aside. Spiropyran, dispersant and defoamer were mixed evenly and ground to a fineness of 20 μm. The remaining components were added and stirred at a speed of 800 r / min for 1 h. The mixture was pressure filtered to obtain a highly weather-resistant daylight-changing offset printing ink.

[0039] Example 4 45 g of rosin-modified phenolic resin prepared in Preparation Example 2, 15 g of hydroxy acrylic resin prepared in Preparation Example 4, 15 g of mineral oil, 10 g of 1,4-di(oxirane-2-yl)benzene-modified spiropyran prepared in Preparation Example 1, 2 g of dispersant, and 2 g of defoaming agent.

[0040] The raw materials were weighed by mass and set aside. Spiropyran, dispersant and defoamer were mixed evenly and ground to a fineness of 20 μm. The remaining components were added and stirred at a speed of 800 r / min for 1 h. The mixture was pressure filtered to obtain a highly weather-resistant daylight-changing offset printing ink.

[0041] Example 5 45 g of rosin-modified phenolic resin prepared in Preparation Example 2, 15 g of hydroxy acrylic resin prepared in Preparation Example 4, 15 g of mineral oil, 15 g of 1,4-dibenzyloxybenzene-modified spiropyran prepared in Preparation Example 6, 2 g of dispersant, and 2 g of defoaming agent.

[0042] The raw materials were weighed by mass and set aside. Spiropyran, dispersant and defoamer were mixed evenly and ground to a fineness of 20 μm. The remaining components were added and stirred at a speed of 800 r / min for 1 h. The mixture was pressure filtered to obtain a highly weather-resistant daylight-changing offset printing ink.

[0043] Example 6 45 g of furanized rosin phenolic resin prepared in Preparation Example 3, 15 g of hydroxy acrylic resin prepared in Preparation Example 4, 15 g of mineral oil, 13 g of 1,4-di(oxirane-2-yl)benzene-modified spiropyran prepared in Preparation Example 1, 2 g of dispersant, and 2 g of defoaming agent.

[0044] The raw materials were weighed by mass and set aside. Spiropyran, dispersant and defoamer were mixed evenly and ground to a fineness of 20 μm. The remaining components were added and stirred at a speed of 800 r / min for 1 h. The mixture was pressure filtered to obtain a highly weather-resistant daylight-changing offset printing ink.

[0045] Example 7 45 g of rosin-modified phenolic resin prepared in Preparation Example 2, 15 g of polyimidized carboxyl acrylic resin prepared in Preparation Example 5, 15 g of mineral oil, 13 g of 1,4-di(oxirane-2-yl)benzene-modified spiropyran prepared in Preparation Example 1, 2 g of dispersant, and 2 g of defoaming agent.

[0046] The raw materials were weighed by mass and set aside. Spiropyran, dispersant and defoamer were mixed evenly and ground to a fineness of 20 μm. The remaining components were added and stirred at a speed of 800 r / min for 1 h. The mixture was pressure filtered to obtain a highly weather-resistant daylight-changing offset printing ink.

[0047] Example 8 45 g of furanized rosin phenolic resin prepared in Preparation Example 3, 15 g of polyimidized carboxyl acrylic resin prepared in Preparation Example 5, 15 g of mineral oil, 13 g of 1,4-di(oxirane-2-yl)benzene-modified spiropyran prepared in Preparation Example 1, 2 g of dispersant, and 2 g of defoaming agent.

[0048] The raw materials were weighed by mass and set aside. Spiropyran, dispersant and defoamer were mixed evenly and ground to a fineness of 20 μm. The remaining components were added and stirred at a speed of 800 r / min for 1 h. The mixture was pressure filtered to obtain a highly weather-resistant daylight-changing offset printing ink.

[0049] Comparative Example Comparative Example 1 60 g of rosin-modified phenolic resin prepared in Preparation Example 2, 15 g of mineral oil, 15 g of spiropyran, 2 g of dispersant, and 2 g of defoamer.

[0050] The raw materials were weighed by mass and set aside. Spiropyran, dispersant and defoamer were mixed evenly and ground to a fineness of 20 μm. The remaining components were added and stirred at a speed of 800 r / min for 1 h. The mixture was pressure filtered to obtain a highly weather-resistant daylight-changing offset printing ink.

[0051] Performance testing Samples of LED-curable inks for flexible printing prepared in each example and comparative example were coated on a PET substrate using a flexible printing method and cured at an irradiation distance of 5 mm. The following tests were performed: 1. Test the ink adhesion level according to the national standard GB / T 13217.7 2023 ink adhesion test method; Second, the samples prepared in each example and comparative example were coated with a thickness of (1.5±0.2) and then placed in a constant temperature and humidity chamber for 40 days of heat and humidity aging treatment at 85°C and 85%. The samples were then exposed to a xenon lamp with a color temperature between 5500 and 6500 K and an irradiance of 42 W / m² (wavelength of 300 to 400 nm). The samples were allowed to change color and were then measured using an automatic ink color and color difference tester to determine the color shift between the samples and the unheat and humidity aging samples.

[0052] The results are summarized in Table 1.

[0053] Table 1 In combination with Examples 1-5 and Comparative Example 1 and Table 1, it can be seen that the present application stacks a certain mass of rosin-modified phenolic resin and hydroxyl acrylic resin together, fills with mineral oil, and further uses a certain mass proportion of 1,4-di(oxirane-2-yl)benzene-modified spiropyran as a photochromic pigment, making it difficult for water and oxygen to invade, and still has good photochromic ability after wet heat aging.

[0054] In combination with Examples 3, 6-8 and Table 1, it can be seen that the present application, by furanizing the rosin phenolic resin and polyimidizing the carboxyl acrylic resin, uniformly distributes Diels-Alder dynamic bonds in the ink, which not only imparts self-healing ability to the coating without significantly sacrificing weather resistance, but also enables the open-ring spiropyran to be better restored, further extending the stable ink color change performance in wet, hot, and oxygen environments.

[0055] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A highly weather-resistant sunlight-changing offset printing ink, characterized in that: The invention comprises the following components in parts by mass: 40-50 parts of rosin-modified phenolic resin, 10-20 parts of hydroxy acrylic resin, 10-20 parts of mineral oil, 10-25 parts of photochromic pigment, and 1-6 parts of auxiliary agent. The photochromic pigment comprises one or more of spiropyran and its derivatives, spirooxanes and its derivatives, fulgide and its derivatives, azo compounds, and triarylmethane and its derivatives.

2. The highly weather-resistant daylight-changing offset printing ink according to claim 1, characterized in that: The photochromic pigment includes 1,4-di(oxiran-2-yl)benzene-modified spiropyran.

3. The highly weather-resistant sunlight-chromic offset printing ink according to claim 2, characterized in that: The 1,4-di(oxiran-2-yl)benzene-modified spiropyran comprises the following preparation steps: adding spiropyran to chloroform, adding ferric chloride, slowly adding 1,4-di(oxiran-2-yl)benzene dropwise, reacting at low temperature under an argon atmosphere, cooling, adding acetone, extracting with ethanol Soxhlet, and vacuum drying to obtain 1,4-di(oxiran-2-yl)benzene-modified spiropyran.

4. The highly weather-resistant sunlight-chromic offset printing ink according to claim 2, characterized in that: In the preparation step of the 1,4-di(oxirane-2-yl)benzene-modified spiropyran, the reaction temperature is 20-30° C. and the reaction time is 8-12 hours.

5. The highly weather-resistant daylight-changing offset printing ink according to claim 3, characterized in that: The mass ratio of the 1,4-di(2-oxirane-1,4-diol)benzene, spiropyran and ferric chloride is 1:0.5:(0.15-0.20).

6. The highly weather-resistant sunlight-chromic offset printing ink according to claim 1, characterized in that: The mass ratio of the rosin-modified phenolic resin, the hydroxy acrylic resin, and the photochromic pigment is 3:(0.9-1.3):(1.2-1.3).

7. The highly weather-resistant sunlight-chromic offset printing ink according to claim 1, characterized in that: The rosin-modified phenolic resin is a furanized rosin phenolic resin, and the carboxyl acrylic resin is a polyimidized carboxyl acrylic resin.

8. The highly weather-resistant daylight-changing offset printing ink according to claim 1, characterized in that: The mass ratio of the rosin-modified phenolic resin, the hydroxy acrylic resin, and the photochromic pigment is 3:1:1.

3.

9. A method for preparing a highly weather-resistant daylight-changing offset printing ink according to any one of claims 1 to 8, characterized in that: The following steps are involved: The raw materials are weighed by mass and set aside, the photochromic pigment and the additive are mixed evenly, and ground to a fineness of less than 20 μm, and the remaining components are added to obtain a highly weather-resistant daylight-changing offset printing ink.

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