Halogen-free flame-retardant ink for plastic film and preparation method of halogen-free flame-retardant ink

Abstract

The invention discloses halogen-free flame-retardant printing ink for a plastic film, and relates to the technical field of printing ink, and the halogen-free flame-retardant printing ink comprises the following components in parts by weight: composite acrylic resin; a composite flame retardant; a dispersant; an auxiliary agent; a solvent; the composite flame retardant is prepared from a modified cyclic phosphazene oligomer, phytate ZIF-8 and ammonium polyphosphate; wherein in the preparation process of the modified cyclic phosphazene oligomer, a polymer chain is initiated to spontaneously wind a phosphazene ring by rapidly injecting low-temperature diethyl ether, then the polymer chain is swelled through supercritical CO2, so that a polyethylene glycol section in tetrahydrofuran polyethylene glycol ether is stretched and penetrates into the phosphazene ring, a hexafluoroisopropanol solution shrinks to form a molecular knot, and the modified cyclic phosphazene oligomer is prepared. Anthraquinone and lone pair electrons in a phosphazene ring are combined after heating, a complexing structure is frozen after cooling, the structure is solidified through final spray granulation, so that the overall structure forms a topological structure, the phosphazene ring can be directionally arranged during combustion, a continuous phosphorus-nitrogen barrier layer is formed, and the flame retardance is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of inks, and in particular to a halogen-free flame-retardant ink for plastic films and a preparation method thereof. Background Art

[0002] With the widespread application of plastic films in electronic equipment, construction engineering, packaging materials, and other fields, the requirements for their flame retardancy and film adhesion are increasing. Traditional halogen-containing flame retardant inks, while effective in flame retardancy, have numerous drawbacks in terms of environmental protection and film adhesion, making them unable to meet the modern industry's demand for high-performance, environmentally friendly inks.

[0003] Currently, halogenated flame retardants such as octabromodiphenyl ether and pentabromodiphenyl ether are widely used in flame retardant inks for plastic films due to their organic flame retardant properties, good compatibility with plastics, high flame retardant effectiveness, and low cost. However, halogenated flame retardants produce carcinogens such as dioxins when burned, posing a serious threat to the environment and human health. The use of octabromodiphenyl ether and pentabromodiphenyl ether is currently banned, and decabromodiphenyl ether has been listed as a flame retardant not to be used due to controversy. Although my country has not yet implemented a complete restriction on decabromodiphenyl ether, its potential hazards cannot be ignored. Furthermore, halogenated flame retardant inks also have insufficient adhesion to plastic films, resulting in ink bleeding and loss on the film surface, which affects print quality and overall product performance.

[0004] Therefore, the development of a halogen-free flame retardant ink for plastic film and a preparation method thereof has important practical significance. However, the flame retardant properties of the halogen-free flame retardant ink and the bonding performance between the ink and the film still need to be further improved. Summary of the Invention

[0005] The purpose of the present invention is to provide a halogen-free flame-retardant ink for plastic film and a preparation method thereof, to solve the following technical problems: How to improve the flame retardancy and adhesion of halogen-free flame retardant inks used in plastic films.

[0006] The purpose of the present invention can be achieved through the following technical solutions: In a first aspect, the present invention discloses a halogen-free flame retardant ink for plastic film, which comprises the following components in parts by weight: 25-35 parts of composite acrylic resin; 18-22 parts of composite flame retardant; 1.5-2.5 parts of dispersant; 0.8-1.2 parts of auxiliary agent; and 15-36 parts of solvent.

[0007] Preferably, the composition comprises the following components in parts by weight: 30 parts of composite acrylic resin; 20 parts of composite flame retardant; 2 parts of dispersant; 1 part of auxiliary agent; and 25 parts of solvent.

[0008] Furthermore, the composite flame retardant comprises a modified cyclic phosphazene oligomer, phytated ZIF-8 and ammonium polyphosphate in a mass ratio of (11-15):6:4.

[0009] Preferably, the composite flame retardant comprises modified cyclic phosphazene oligomer, phytated ZIF-8 and ammonium polyphosphate in a mass ratio of 13:6:4.

[0010] Furthermore, the preparation method of the modified cyclic phosphazene oligomer comprises the following steps: Step A1, dissolving a cyclic phosphazene oligomer and tetrahydrofuran polyglycol ether in a mass ratio of 10:3 in hexafluoroisopropanol to form a mixed solution with a solute mass fraction of 10 wt%, then injecting diethyl ether cooled by liquid nitrogen at a temperature of -50°C, stirring and reacting for 10 minutes, collecting the precipitate by centrifugation, and vacuum drying to obtain Product A; Step A2, the product A and sodium anthraquinone disulfonate according to a mass ratio of 108:1 was placed in a supercritical reactor, and supercritical CO2 was introduced at 35 ° C, 25MPa for 4h; Step A3, raising the internal temperature of the supercritical reactor to 80° C. and maintaining it for 5 minutes, then suddenly lowering it to -30° C. and maintaining it for 10 minutes to obtain product B; Step A4: Disperse the product B in a 0.5% by mass perfluoropolyether propionate-HFE-7100 solution, stir ultrasonically for 30 minutes, and then spray-dry to form a modified cyclic phosphazene oligomer.

[0011] Furthermore, in step A1, the cyclic phosphazene oligomer is hexachlorocyclotriphosphazene.

[0012] Furthermore, in step A1, the volume ratio of diethyl ether to hexafluoroisopropanol is (5.5-6):1; Preferably, the volume ratio of diethyl ether to hexafluoroisopropanol is 5.8:1.

[0013] Furthermore, in step A3, the temperature inside the supercritical reactor is raised to 80°C at a rate of 3-5°C / min and then dropped to -30°C at a rate of 6-8°C / min; Preferably, the temperature inside the supercritical reactor is raised to 80° C. at a heating rate of 4° C. / min, and is dropped to -30° C. at a cooling rate of 7° C. / min.

[0014] Furthermore, the composite acrylic resin is formed by mixing methyl methacrylate, butyl acrylate and ethyl methacrylate phosphate in a mass ratio of 1:1:1.

[0015] Furthermore, the preparation method of phytic acid ZIF-8 includes the following steps: dispersing ZIF-8 in ethanol, adding phytic acid aqueous solution, stirring and reacting at 60°C for 4 hours, centrifuging and washing, and then vacuum drying; wherein the mass ratio of ZIF-8 to phytic acid is 5:1.

[0016] Furthermore, the dispersant is polyisobutylene-b-polybutyl acrylate.

[0017] Furthermore, the auxiliary agent is TiO2 / SiO2 composite particles, which are core-shell particles formed by nano-TiO2 coating gas-phase SiO2.

[0018] Furthermore, the solvent is a mixed solvent of n-propyl acetate and propylene glycol methyl ether acetate in a volume ratio of 7:3.

[0019] In a second aspect, the present invention further discloses a method for preparing the halogen-free flame retardant ink for plastic film as described above, comprising the following steps: Step 1: dissolving phytated ZIF-8 in 0.1 times the amount of solvent and pre-dispersing by ball milling for 2 hours to obtain a pre-dispersion liquid; dissolving the composite acrylic resin and the modified cyclic phosphazene oligomer in the remaining solvent, stirring at 55° C. for 1 hour, then adding the dispersion liquid, and treating at 2500 rpm for 30 minutes to obtain a mixed solution; Step 2: Cool the mixed solution to 25° C., add ammonium polyphosphate and dispersant, continue to disperse for 20 minutes, then cool to 5° C., add auxiliary agent and ultrasonically treat for 30 minutes, and filter to obtain halogen-free flame retardant ink for plastic film.

[0020] Beneficial effects of the present invention: The flame retardant in the halogen-free flame retardant ink for plastic film of the present invention is a composite flame retardant formed by three flame retardant components, namely, a modified cyclic phosphazene oligomer, phytated ZIF-8, and ammonium polyphosphate. In the preparation process of the modified cyclic phosphazene oligomer, low-temperature ether is rapidly injected to induce the polymer chain to spontaneously entangle the phosphazene ring. Then, supercritical CO2 is used to swell the polymer chain, causing the polyethylene glycol segment in the tetrahydrofuran polyethylene glycol ether to stretch and penetrate the phosphazene ring. The hexafluoroisopropanol solution shrinks to form a molecular junction. After heating, anthraquinone combines with the lone pair electrons in the phosphazene ring. After cooling, the complex structure is frozen. Finally, the structure is solidified by spray granulation, so that the overall structure forms a topological structure. During combustion, the phosphazene ring can be oriented to form a continuous phosphorus-nitrogen barrier layer, thereby enhancing the flame retardancy. In addition, the phytated ZIF-8 and ammonium polyphosphate synergistically enhance the performance of the modified cyclic phosphazene oligomer, thereby significantly improving the flame retardancy of the ink.

[0021] Because the topological structure formed by the modified cyclic phosphazene oligomer is relatively stable, it can maintain a certain degree of structural integrity when the external temperature, pH value, etc. change. This stability makes the modified cyclic phosphazene oligomer less likely to undergo structural damage or separation due to external factors after being combined with the plastic film, thus ensuring the durability of the bonding force. Moreover, during the combustion process, the topological structure formed by the modified cyclic phosphazene oligomer will consume energy and shrink. Therefore, under the action of shrinkage stress, it will cling to the film surface, thereby enhancing the bonding force with the film surface. DETAILED DESCRIPTION

[0022] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0023] Unless otherwise specified, the experimental methods in the following examples are conventional methods and were performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials and reagents used in the following examples, unless otherwise specified, were all commercially available.

[0024] Preparation Example 1 The modified cyclic phosphazene oligomer is prepared by following the steps below: Step a1: In a beaker, dissolve 10 g of hexachlorocyclotriphosphazene and 3 g of tetrahydrofuran polyglycol ether in 117 g of hexafluoroisopropanol, then inject diethyl ether cooled by liquid nitrogen at -50°C, stir and react for 10 minutes, collect the precipitate by centrifugation, and vacuum dry to obtain Product A; Step a2, 10.8g of product A and 0.1g of sodium anthraquinone disulfonate were placed in a supercritical reactor, and supercritical CO2 was introduced at 35 ° C, 25MPa for 4h; Step a3, raising the internal temperature of the supercritical reactor to 80°C at a heating rate of 4°C / min and holding the temperature therein for 5 min, then cooling the temperature to -30°C at a cooling rate of 7°C / min and holding the temperature therein for 10 min, to obtain a product B; Step a4: 10 g of product B was dispersed in 90 mL of a 0.5% by mass perfluoropolyether propionate-HFE-7100 solution, ultrasonically stirred for 30 min, and then spray-dried (inlet 180° C., outlet 80° C.) to form a modified cyclic phosphazene oligomer.

[0025] Repeating the above steps can obtain a sufficient amount of modified cyclic phosphazene oligomer.

[0026] Preparation Example 2 To prepare phytated ZIF-8, follow the steps below: In a beaker, 10 g of ZIF-8 was dispersed in 100 mL of ethanol, and 8 g of a 25% phytic acid aqueous solution was added. The mixture was stirred and reacted at 60 °C for 4 h. After centrifugation and washing, the mixture was placed in a vacuum drying oven and vacuum dried at 80 °C for 2 h to obtain phytic acid-treated ZIF-8.

[0027] Repeat the above steps to obtain a sufficient amount of phytated ZIF-8.

[0028] Preparation Example 3 Preparation of composite acrylic resin: Methyl methacrylate, butyl acrylate and ethyl methacrylate phosphate were added into a mixer in a mass ratio of 1:1:1 and mixed for 30 minutes to obtain a composite acrylic resin.

[0029] Preparation Example 4 Prepare a solvent: Mix n-propyl acetate and propylene glycol methyl ether acetate in a volume ratio of 7:3 to obtain a solvent. Example 1

[0030] The preparation of halogen-free flame-retardant ink for plastic film is carried out in the following steps: Step 1, 5.22g of phytated ZIF-8 prepared in Preparation Example 2 was dissolved in 2.5g of the solvent prepared in Preparation Example 4, and ball milled for 2h for pre-dispersion to obtain a pre-dispersion liquid; 30g of the composite acrylic resin prepared in Preparation Example 3 and 11.30g of the modified cyclic phosphazene oligomer prepared in Preparation Example 1 were dissolved in 22.5g of the solvent prepared in Preparation Example 4, stirred at 55°C for 1h, and then the dispersion was added and treated at 2500rpm for 30min to obtain a mixed solution; Step 2: Cool the mixed solution to 25°C, add 3.48g of ammonium polyphosphate and 2g of polyisobutylene-b-polybutyl acrylate (purchased from Xi'an Qiyue Biotechnology Co., Ltd.), continue to disperse for 20 minutes, then cool to 5°C, add 1g of TiO2 / SiO2 composite particles (purchased from Xi'an Qiyue Biotechnology Co., Ltd., which are core-shell particles formed by nano-TiO2 coated with gas-phase SiO2), and ultrasonically treat for 30 minutes. After filtering, a halogen-free flame retardant ink for plastic film is obtained. Example 2

[0031] The preparation of halogen-free flame-retardant ink for plastic film is carried out in the following steps: Step 1, 4.70g of phytated ZIF-8 prepared in Preparation Example 2 was dissolved in 1.5g of the solvent prepared in Preparation Example 4, and ball milled for 2h for pre-dispersion to obtain a pre-dispersion liquid; 25g of the composite acrylic resin prepared in Preparation Example 3 and 10.17g of the modified cyclic phosphazene oligomer prepared in Preparation Example 1 were dissolved in 13.5g of the solvent prepared in Preparation Example 4, stirred at 55°C for 1h, and then the dispersion was added and treated at 2500rpm for 30min to obtain a mixed solution; Step 2: Cool the mixed solution to 25°C, add 3.13g of ammonium polyphosphate and 1.5g of polyisobutylene-b-polybutyl acrylate (purchased from Xi'an Qiyue Biotechnology Co., Ltd.), continue to disperse for 20 minutes, then cool to 5°C, add 0.8g of TiO2 / SiO2 composite particles (purchased from Xi'an Qiyue Biotechnology Co., Ltd., which are core-shell particles formed by nano-TiO2 coated with gas-phase SiO2), and ultrasonically treat for 30 minutes. After filtering, a halogen-free flame retardant ink for plastic film is obtained. Example 3

[0032] The preparation of halogen-free flame-retardant ink for plastic film is carried out in the following steps: Step 1, 5.74 g of phytated ZIF-8 prepared in Preparation Example 2 was dissolved in 3.6 g of the solvent prepared in Preparation Example 4, and ball milled for 2 h for pre-dispersion to obtain a pre-dispersion liquid; 35 g of the composite acrylic resin prepared in Preparation Example 3 and 12.43 g of the modified cyclic phosphazene oligomer prepared in Preparation Example 1 were dissolved in 32.4 g of the solvent prepared in Preparation Example 4, stirred at 55 ° C for 1 h, and then the dispersion was added and treated at 2500 rpm for 30 min to obtain a mixed solution; Step 2: Cool the mixed solution to 25°C, add 3.83g of ammonium polyphosphate and 2.5g of polyisobutylene-b-polybutyl acrylate (purchased from Xi'an Qiyue Biotechnology Co., Ltd.), continue to disperse for 20 minutes, then cool to 5°C, add 1.2g of TiO2 / SiO2 composite particles (purchased from Xi'an Qiyue Biotechnology Co., Ltd., which are core-shell particles formed by nano-TiO2 coated with gas-phase SiO2), and ultrasonically treat for 30 minutes. After filtering, a halogen-free flame retardant ink for plastic film is obtained. Example 4

[0033] A halogen-free flame retardant ink for plastic film was prepared. Compared with Example 1, the only difference was that the amount of phytated ZIF-8 prepared in Preparation Example 2 was replaced by 5.71 g, the amount of modified cyclic phosphazene oligomer prepared in Preparation Example 1 was replaced by 10.48 g, and the amount of ammonium polyphosphate was replaced by 3.81 g. The other steps and conditions remained the same, and a halogen-free flame retardant ink for plastic film was finally prepared. Example 5

[0034] A halogen-free flame retardant ink for plastic film was prepared. Compared with Example 1, the only difference was that the amount of phytated ZIF-8 prepared in Preparation Example 2 was replaced by 4.8 g, the amount of modified cyclic phosphazene oligomer prepared in Preparation Example 1 was replaced by 12 g, and the amount of ammonium polyphosphate was replaced by 3.2 g. The other steps and conditions remained the same, and a halogen-free flame retardant ink for plastic film was finally prepared.

[0035] Comparative Example 1 Compared with Example 1, the only difference is that the modified cyclic phosphazene oligomer prepared in Preparation Example 1 is replaced by ammonium polyphosphate, and the other steps and conditions remain the same, and finally a halogen-free flame retardant ink for plastic film is prepared.

[0036] Comparative Example 2 Compared with Example 1, the only difference is that the phytated ZIF-8 prepared in Preparation Example 2 is replaced by ammonium polyphosphate, and the other steps and conditions remain the same, and finally a halogen-free flame retardant ink for plastic film is prepared.

[0037] Comparative Example 3 Compared with Example 1, the only difference is that the modified cyclic phosphazene oligomer prepared in Preparation Example 1 and the phytated ZIF-8 prepared in Preparation Example 2 are replaced by ammonium polyphosphate, and the other steps and conditions remain the same, and finally a halogen-free flame retardant ink for plastic film is prepared.

[0038] The plastic films prepared in Examples 1-5 and Comparative Examples 1-3 were coated on PET films with a length of 20 cm, a width of 15 cm, and a thickness of 4 mm, respectively, with a coating thickness of 0.1 mm. The films were then placed in an oven and cured at 60° C. for 1 hour. After removal, performance tests were performed. The test method was as follows: Film vertical burning test: refer to ASTM D4804.

[0039] Limiting Oxygen Index (LOI): Refer to ASTM D2863.

[0040] 180° peel strength test: refer to GB / T 2792-2014.

[0041] The test results are listed in Table 1, which is as follows:

[0042] Analysis of the data in Table 1 shows that, compared with Comparative Examples 1-3, the halogen-free flame retardant inks for plastic films prepared in Examples 1-5 have significantly higher flame retardancy levels, oxygen indices, and peel strengths when applied to PET films. This demonstrates that the halogen-free flame retardant inks for plastic films of the present invention have excellent flame retardancy and mechanical bonding strength.

[0043] The above describes in detail several embodiments of the present invention. However, the above contents are only preferred embodiments of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A halogen-free flame-retardant ink for plastic film, characterized in that: The components include the following in parts by weight: 25-35 parts of composite acrylic resin; 18-22 parts of composite flame retardant; 1.5-2.5 parts of dispersant; 0.8-1.2 parts of auxiliary agent; 15-36 parts of solvent; The composite flame retardant comprises a modified cyclic phosphazene oligomer, phytated ZIF-8 and ammonium polyphosphate in a mass ratio of (11-15):6:

4.

2. The halogen-free flame-retardant ink for plastic film according to claim 1, characterized in that: The preparation method of the modified cyclic phosphazene oligomer comprises the following steps: Step A1, dissolving a cyclic phosphazene oligomer and tetrahydrofuran polyglycol ether in a mass ratio of 10:3 in hexafluoroisopropanol to form a mixed solution with a solute mass fraction of 10 wt%, then injecting diethyl ether cooled by liquid nitrogen at a temperature of -50°C, stirring and reacting for 10 minutes, collecting the precipitate by centrifugation, and vacuum drying to obtain Product A; Step A2, the product A and sodium anthraquinone disulfonate according to a mass ratio of 108:1 was placed in a supercritical reactor, and supercritical CO2 was introduced at 35 ° C, 25MPa for 4h; Step A3, raising the internal temperature of the supercritical reactor to 80° C. and maintaining it for 5 minutes, then suddenly lowering it to -30° C. and maintaining it for 10 minutes to obtain product B; Step A4: Disperse the product B in a 0.5% by mass perfluoropolyether propionate-HFE-7100 solution, stir ultrasonically for 30 minutes, and then spray-dry to form a modified cyclic phosphazene oligomer.

3. The halogen-free flame-retardant ink for plastic film according to claim 2, characterized in that: In step A1, the volume ratio of diethyl ether to hexafluoroisopropanol is (5.5-6):

1.

4. The halogen-free flame-retardant ink for plastic film according to claim 2, characterized in that: In step A3, the temperature inside the supercritical reactor is raised to 80°C at a heating rate of 3-5°C / min, and is suddenly dropped to -30°C at a cooling rate of 6-8°C / min.

5. The halogen-free flame-retardant ink for plastic film according to claim 1, characterized in that: The composite acrylic resin is formed by mixing methyl methacrylate, butyl acrylate and ethyl methacrylate phosphate in a mass ratio of 1:1:

1.

6. The halogen-free flame-retardant ink for plastic film according to claim 1, characterized in that: The preparation method of phytic acidized ZIF-8 comprises the following steps: dispersing ZIF-8 in ethanol, adding a phytic acid aqueous solution, stirring and reacting at 60° C. for 4 hours, centrifuging and washing, and then vacuum drying; wherein the mass ratio of ZIF-8 to phytic acid is 5:

1.

7. The halogen-free flame-retardant ink for plastic film according to claim 1, characterized in that: The dispersant is polyisobutylene-b-polybutyl acrylate.

8. The halogen-free flame-retardant ink for plastic film according to claim 1, wherein: The auxiliary agent is TiO2 / SiO2 composite particles, which are core-shell particles formed by nano-TiO2 coating gas-phase SiO2.

9. The halogen-free flame-retardant ink for plastic film according to claim 1, characterized in that: The solvent is a mixed solvent of n-propyl acetate and propylene glycol methyl ether acetate in a volume ratio of 7:

3.

10. A method for preparing the halogen-free flame retardant ink for plastic film according to any one of claims 1 to 9, characterized in that: The steps include: Step 1: dissolving phytated ZIF-8 in 0.1 times the amount of solvent and pre-dispersing by ball milling for 2 hours to obtain a pre-dispersion liquid; dissolving the composite acrylic resin and the modified cyclic phosphazene oligomer in the remaining solvent, stirring at 55° C. for 1 hour, then adding the dispersion liquid, and treating at 2500 rpm for 30 minutes to obtain a mixed solution; Step 2: Cool the mixed solution to 25° C., add ammonium polyphosphate and dispersant, continue to disperse for 20 minutes, then cool to 5° C., add auxiliary agent and ultrasonically treat for 30 minutes, and filter to obtain halogen-free flame retardant ink for plastic film.

Images