A preparation method of biodegradable green printing ink

Abstract

The present invention relates to a method for preparing a biodegradable green printing ink, and belongs to the technical field of ink preparation. Polylactic acid microspheres, isopropyl alcohol, pigment, defoamer, leveling agent, surfactant, ammonia water, and deionized water are mixed and stirred evenly in a high-speed disperser to obtain a biodegradable green printing ink. The polylactic acid microspheres of the present invention are dehydrated and condensed by a lactic acid aqueous solution to obtain polylactic acid seed microspheres; polylactic acid seed microspheres, γ-aminopropyltriethoxysilane, benzoyl peroxide, and triethanolamine monooleate are stirred and mixed, and then di-tert-butylmethylphenol is added to cause a swelling reaction to obtain polylactic acid microspheres; the polylactic acid microspheres are taken, placed in a low-temperature plasma treatment device, and the polylactic acid microspheres are subjected to plasma treatment to obtain the biodegradable green printing ink. The biodegradable green printing ink prepared by the present invention has a high degradation rate and is almost completely degraded after 100 days; the ink of the present invention has high adhesion fastness, good initial drying properties, and excellent comprehensive performance of the ink.

Description

Technical Field

[0001] The invention relates to the technical field of ink preparation, in particular to a method for preparing biodegradable green printing ink. Background Art

[0002] China has become the world's second-largest ink producer, with hundreds of small and medium-sized manufacturers scattered across the country. Meanwhile, while there are over 200 water-based ink manufacturers, only a handful boast annual production exceeding 1,000 tons. Domestic demand for specialty printing inks, such as offset lithographic inks, screen printing inks, and flexographic inks, is on the rise. Furthermore, as awareness of sustainable development grows, demand for more advanced, environmentally friendly inks, such as alcohol-soluble and water-based inks, is also expected to grow rapidly.

[0003] Chinese patent CN115838547A: discloses a method for preparing a water-based ink for PVC decorative film, which includes, by weight: 2-6 parts of polyvinyl alcohol grinding resin, 10-18 parts of pigment, 1-3 parts of dispersant, 0.1-0.5 parts of defoamer, 20-35 parts of water-based epoxy resin, 0.5-1.5 parts of wetting agent, 1-2 parts of cosolvent, 13-40 parts of purified water, 1-1.5 parts of surfactant, 20-40 parts of water-based PVC glue, 1-3 parts of nano-titanium dioxide dispersion, 0.5-1 part of polyethylene wax powder, and 20-35 parts of ethyl acetate.

[0004] Chinese patent CN115449260A relates to the field of ink processing and specifically discloses a water-based ink and its preparation method. The water-based ink includes a composite binder, which includes a modified epoxy resin, an acrylic resin, and a silicone resin. The mass ratio of the modified epoxy resin, acrylic resin, and silicone resin is (1.2-2.0): (2.3-3.1): (0.8-1.9). The preparation method comprises the following steps: S1: preparing the composite binder; S2: adding a pigment, deionized water, and a surfactant to the mixed composite binder and stirring thoroughly to obtain a matrix mixture; S3: sequentially adding ammonia water, a thickener, a polyether-modified polysiloxane defoamer, an ink diluent, a slow-drying agent, and a candle agent to the matrix mixture and stirring and mixing, thereby obtaining the water-based ink.

[0005] Chinese patent CN110669376A discloses a general method for preparing high-end water-based UV ink, relating to the technical field of water-based ink preparation. The method comprises adding 40-55 parts of a silicone-modified water-based polyurethane acrylate prepolymer and 20-30 parts of an acrylate monomer to a mixing barrel and stirring at 700-1000 rpm for 10-20 minutes; transferring the pre-dispersed liquid to a grinder and grinding it 1-3 times; transferring the ground liquid to a mixing barrel, adding 1-10 parts of a photoinitiator, 5-10 parts of a pigment, 5-15 parts of a solvent, and 1-5 parts of an additive to the mixing barrel; and stirring at 700-1000 rpm for 20-30 minutes until the mixture is uniformly mixed to obtain a water-based UV ink.

[0006] The inks prepared by the above patents and prior art mostly use non-degradable resin materials as binders, which are harmful to the environment, food, etc., and generally have high production costs, which are neither economical nor environmentally friendly. Summary of the Invention

[0007] In order to solve the above problems, the present invention provides a method for preparing a biodegradable green printing ink, the operating steps of which are as follows:

[0008] 30-40 parts of polylactic acid microspheres, 10-15 parts of isopropyl alcohol, 10-15 parts of pigment, 1-3 parts of defoaming agent, 1-3 parts of leveling agent, 1-3 parts of surfactant, 1-5 parts of ammonia water and 15-25 parts of deionized water are mixed and stirred uniformly in a high-speed disperser to obtain a biodegradable green printing ink.

[0009] As a preferred embodiment, the pigment is one of methyl orange, methyl blue, crystal violet, carbon black, titanium dioxide, magenta 6B, and benzidine yellow.

[0010] As a preferred embodiment, the defoaming agent is one of dimethyl polysiloxane, trimethyl silicone oil, mineral oil, emulsified silicone oil, polyoxyethylene polyoxypropylene pentaerythritol ether, polyoxyethylene polyoxypropanolamine ether, polyoxypropylene glycerol ether, polyoxypropylene polyoxyethylene glycerol ether, and polydimethylsiloxane.

[0011] As a preferred embodiment, the leveling agent is one of BYK-378 leveling agent, hydroxymethyl cellulose, silicone oil, polydimethylsiloxane, polymethylalkylsiloxane, polyether polyester modified organic siloxane, alkyl modified organic siloxane, and polyether modified dimethylpolysiloxane.

[0012] As a preferred embodiment, the surfactant is one of sodium dodecylbenzenesulfonate, sulfated castor oil, sodium dioctyl succinate sulfonate, sodium glycocholate, sodium oleate, and sodium ligninsulfonate.

[0013] As a preferred embodiment, the preparation method of the polylactic acid microspheres is:

[0014] A1: Dehydrate and condense the lactic acid aqueous solution at 170-180°C to obtain polylactic acid seed microspheres;

[0015] A2: 60-90 parts of polylactic acid seed microspheres, 1-5 parts of γ-aminopropyltriethoxysilane, 1-3 parts of benzoyl peroxide, and 1-3 parts of triethanolamine monooleate are stirred and mixed, and then 1-3 parts of di-tert-butylmethylphenol are added to cause a swelling reaction to obtain polylactic acid microspheres;

[0016] A3: 40-100 portions of polylactic acid microspheres are placed in a low-temperature plasma treatment apparatus. Mixed steam is selected as the carrier gas, the airflow rate is controlled at 10-20 ml / min, and the power is adjusted to 100-200 watts. The polylactic acid microspheres are subjected to plasma treatment for 30-60 minutes to obtain modified polylactic acid microspheres.

[0017] As a preferred solution, the mixed steam is a mixed steam of ammonia, (+)-limonene 1,2-epoxide, and biphenyl-4,4'-dithiol CAS No. 6954-27-4, with a volume ratio of 1:0.2-0.5:0.002-0.03.

[0018] Reaction mechanism

[0019] 1. Plasma modification to introduce amino groups

[0020] The polylactic acid microspheres are first treated with plasma to activate their surface to form free radicals or ions, which then react with amino-containing compounds (such as aminosilane coupling agents) to successfully introduce amino groups onto the microsphere surface; this process provides the necessary functional groups for subsequent chemical reactions.

[0021] 2. Ring-opening addition reaction of amine group and epoxy group

[0022] The amino groups introduced onto the surface of the polylactic acid microspheres undergo a ring-opening addition reaction with the epoxy groups in (+)-limonene 1,2-epoxide; the amino groups act as nucleophiles to attack the carbon atoms on the epoxy ring, resulting in the opening of the ring and the formation of a new hydroxyl group and secondary amino group, which means that the limonene group is covalently bonded to the surface of the microspheres.

[0023] 3. Mercapto-epoxy ring-opening addition reaction

[0024] The hydroxyl group formed in the second step can continue to undergo a ring-opening addition reaction with the thiol group in biphenyl-4,4'-dithiol; similarly, the thiol group acts as a nucleophile to attack the carbon atom next to the hydroxyl group, causing ring opening and forming a new thioether bond to connect the biphenyl group, thus completing the surface functionalization of the polylactic acid microspheres.

[0025] Technical Effects

[0026] The present invention provides a method for preparing a biodegradable green printing ink. Compared with the prior art, the present invention has the following significant effects:

[0027] 1. Improve surface roughness and chemical diversity

[0028] By grafting limonene and biphenyl groups, the surface of the polylactic acid microspheres becomes rough and the chemical properties become more diverse; this physical and chemical change is conducive to enhancing the interaction with other components in the ink, including providing more possible hydrogen bonds and electrostatic attraction, thereby significantly improving the adhesion of the ink.

[0029] 2. Improve dispersibility and wettability

[0030] The increased surface polarity of the modified microspheres helps improve their dispersibility and wettability in the ink; this not only facilitates the uniform distribution of the ink, but also contributes to the uniformity of the film layer after drying, further promoting the improvement of ink adhesion.

[0031] 3. Enhanced compatibility

[0032] The introduced limonene and biphenyl groups increase the compatibility of the polylactic acid microspheres with other organic components in the ink, reducing the possibility of phase separation; this increased compatibility is conducive to forming a uniform and stable ink system, thereby maintaining good adhesion during and after printing. DETAILED DESCRIPTION

[0033] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention object, the following is a detailed description in conjunction with examples and comparative examples:

[0034] 1. Adhesion fastness and initial drying test: refer to QB / T1046-2012 for testing;

[0035] 2. Degradation rate: The degradation rate of ink after 100 days of burial.

[0036] Example 1

[0037] A method for preparing a biodegradable green printing ink, the operating steps of which are:

[0038] 30 g of polylactic acid microspheres, 10 g of isopropyl alcohol, 10 g of pigment, 1 g of defoamer, 1 g of leveling agent, 1 g of surfactant, 1 g of ammonia water, and 15 g of deionized water were mixed and stirred uniformly in a high-speed disperser to obtain a biodegradable green printing ink.

[0039] The pigment is methyl orange.

[0040] The defoaming agent is dimethyl polysiloxane.

[0041] The leveling agent is BYK-378 leveling agent.

[0042] The surfactant is sodium dodecylbenzenesulfonate.

[0043] The preparation method of the polylactic acid microspheres is:

[0044] A1: Dehydrate and condense an aqueous solution of L-lactic acid (L-LA) at 170°C to obtain polylactic acid seed microspheres;

[0045] A2: 60 g of polylactic acid seed microspheres, 1 g of γ-aminopropyltriethoxysilane, 1 g of benzoyl peroxide, and 1 g of triethanolamine monooleate were stirred and mixed, and then 1 g of di-tert-butylmethylphenol was added to cause a swelling reaction to obtain polylactic acid microspheres;

[0046] A3: Take 40g of PLA microspheres and place them in a low-temperature plasma treatment device; select mixed steam as the carrier gas, control the airflow rate at 10 ml / min, and adjust the power to 100 watts. The PLA microspheres are plasma treated for 30 minutes to obtain modified PLA microspheres.

[0047] The mixed steam is a mixed steam of ammonia, (+)-limonene 1,2-epoxide and biphenyl-4,4'-dithiol CAS No. 6954-27-4, with a volume ratio of 1:0.2:0.002.

[0048] Example 2

[0049] A method for preparing a biodegradable green printing ink, the operating steps of which are:

[0050] 33 g of polylactic acid microspheres, 12 g of isopropyl alcohol, 12 g of pigment, 2 g of defoamer, 2 g of leveling agent, 2 g of surfactant, 2 g of ammonia water, and 18 g of deionized water were mixed and stirred uniformly in a high-speed disperser to obtain a biodegradable green printing ink.

[0051] The pigment is methyl blue.

[0052] The defoaming agent is trimethyl silicone oil.

[0053] The leveling agent is hydroxymethyl cellulose.

[0054] The surfactant is sulfated castor oil.

[0055] The preparation method of the polylactic acid microspheres is:

[0056] A1: Dextrorotatory lactic acid (D-LA) aqueous solution was dehydrated and condensed at 175°C to obtain polylactic acid seed microspheres;

[0057] A2: 70 g of polylactic acid seed microspheres, 2 g of γ-aminopropyltriethoxysilane, 2 g of benzoyl peroxide, and 2 g of triethanolamine monooleate were stirred and mixed, and then 2 g of di-tert-butylmethylphenol was added to cause a swelling reaction to obtain polylactic acid microspheres;

[0058] A3: Take 60g of PLA microspheres and place them in a low-temperature plasma treatment device; select mixed steam as the carrier gas, control the airflow rate to 15 ml / min, and adjust the power to 140 watts. The PLA microspheres are plasma treated for 40 minutes to obtain modified PLA microspheres.

[0059] The mixed steam is a mixed steam of ammonia, (+)-limonene 1,2-epoxide and biphenyl-4,4'-dithiol (CAS No. 6954-27-4), with a volume ratio of 1:0.3:0.01.

[0060] Example 3

[0061] A method for preparing a biodegradable green printing ink, the operating steps of which are:

[0062] 38 g of polylactic acid microspheres, 14 g of isopropyl alcohol, 14 g of pigment, 2 g of defoaming agent, 2 g of leveling agent, 2 g of surfactant, 4 g of ammonia water, and 23 g of deionized water were mixed and stirred in a high-speed disperser to obtain a biodegradable green printing ink.

[0063] The pigment is crystal violet.

[0064] The defoaming agent is mineral oil.

[0065] The leveling agent is silicone oil.

[0066] The surfactant is dioctyl sodium sulfosuccinate.

[0067] The preparation method of the polylactic acid microspheres is:

[0068] A1: Dehydrate and condense the racemic lactic acid (DL-LA) aqueous solution at 175°C to obtain polylactic acid seed microspheres;

[0069] A2: 80 g of polylactic acid seed microspheres, 4 g of γ-aminopropyltriethoxysilane, 2 g of benzoyl peroxide, and 2 g of triethanolamine monooleate were stirred and mixed, and then 2 g of di-tert-butylmethylphenol was added to cause a swelling reaction to obtain polylactic acid microspheres;

[0070] A3: 80 g of PLA microspheres were placed in a low-temperature plasma treatment device. Mixed steam was selected as the carrier gas, the airflow rate was controlled at 15 ml / min, and the power was adjusted to 180 watts. The PLA microspheres were plasma treated for 50 minutes to obtain modified PLA microspheres.

[0071] The mixed steam is a mixed steam of ammonia, (+)-limonene 1,2-epoxide and biphenyl-4,4'-dithiol CAS No. 6954-27-4, with a volume ratio of 1:0.4:0.02.

[0072] Example 4

[0073] A method for preparing a biodegradable green printing ink, the operating steps of which are:

[0074] 40 g of polylactic acid microspheres, 15 g of isopropyl alcohol, 15 g of pigment, 3 g of defoaming agent, 3 g of leveling agent, 3 g of surfactant, 5 g of ammonia water, and 25 g of deionized water were mixed and stirred in a high-speed disperser to obtain a biodegradable green printing ink.

[0075] The pigment is carbon black.

[0076] The defoaming agent is polydimethylsiloxane.

[0077] The leveling agent is polyether modified dimethyl polysiloxane.

[0078] The surfactant is sodium lignin sulfonate.

[0079] The preparation method of the polylactic acid microspheres is:

[0080] A1: Dehydrate and condense the racemic lactic acid (DL-LA) aqueous solution at 180°C to obtain polylactic acid seed microspheres;

[0081] A2: 90 g of polylactic acid seed microspheres, 5 g of γ-aminopropyltriethoxysilane, 3 g of benzoyl peroxide, and 3 g of triethanolamine monooleate were stirred and mixed, and then 3 g of di-tert-butylmethylphenol was added to cause a swelling reaction to obtain polylactic acid microspheres;

[0082] A3: Take 100g of PLA microspheres and place them in a low-temperature plasma treatment device; select mixed steam as the carrier gas, control the airflow rate to 20 ml / min, and adjust the power to 200 watts. The PLA microspheres are plasma treated for 60 minutes to obtain modified PLA microspheres.

[0083] The mixed steam is a mixed steam of ammonia, (+)-limonene 1,2-epoxide and biphenyl-4,4'-dithiol CAS No. 6954-27-4, with a volume ratio of 1:0.5:0.03.

[0084] Comparative Example 1

[0085] The polylactic acid microspheres were not modified, and the other steps were the same as in Example 1.

[0086] Comparative Example 2

[0087] The other steps were the same as in Example 1 except that (+)-limonene 1,2-epoxide was not added.

[0088] Comparative Example 3

[0089] The other steps were the same as in Example 1 except that biphenyl-4,4'-dithiol was not added.

[0090] Adhesion fastness / % Initial drying / mm / 30s Degradation rate / % Example 1 91 39 93 Example 2 94 37 95 Example 3 96 35 98 Example 4 97 34 100 Comparative Example 1 68 66 69 Comparative Example 2 82 49 85 Comparative Example 3 85 46 88

[0091] Through the data analysis of the above examples and comparative examples, the ink prepared by the present invention has a high degradation rate and is almost completely degraded after 100 days. It is an ink material with excellent performance and environmental friendliness. The biodegradable green printing ink prepared by the present invention has high adhesion fastness, good initial drying properties, and excellent comprehensive performance of the ink.

[0092] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a biodegradable green printing ink, comprising the following steps: 30-40 parts of polylactic acid microspheres, 10-15 parts of isopropyl alcohol, 10-15 parts of pigment, 1-3 parts of defoamer, 1-3 parts of leveling agent, 1-3 parts of surfactant, 1-5 parts of ammonia water, and 15-25 parts of deionized water are mixed and stirred in a high-speed disperser to obtain a biodegradable green printing ink; The preparation method of the polylactic acid microspheres is: A1: Dehydrate and condense the lactic acid aqueous solution at 170-180°C to obtain polylactic acid seed microspheres; A2: 60-90 parts of polylactic acid seed microspheres, 1-5 parts of γ-aminopropyltriethoxysilane, 1-3 parts of benzoyl peroxide, and 1-3 parts of triethanolamine monooleate are stirred and mixed, and then 1-3 parts of di-tert-butylmethylphenol are added to cause a swelling reaction to obtain polylactic acid microspheres; A3: 40-100 portions of polylactic acid microspheres are placed in a low-temperature plasma treatment apparatus. Mixed steam is selected as the carrier gas, the airflow rate is controlled at 10-20 ml / min, and the power is adjusted to 100-200 watts. The polylactic acid microspheres are subjected to plasma treatment for 30-60 minutes to obtain modified polylactic acid microspheres. The mixed steam is a mixed steam of ammonia, (+)-limonene 1,2-epoxide and biphenyl-4,4'-dithiol, with a volume ratio of 1:0.2-0.5:0.002-0.

03.

2. The method for preparing a biodegradable green printing ink according to claim 1, wherein: The pigment is one of methyl orange, methyl blue, crystal violet, carbon black, magenta 6B and benzidine yellow.

3. The method for preparing a biodegradable green printing ink according to claim 1, wherein: The defoaming agent is one of dimethyl polysiloxane, trimethyl silicone oil, mineral oil, emulsified silicone oil, polyoxyethylene polyoxypropylene pentaerythritol ether, polyoxyethylene polyoxypropanolamine ether, polyoxypropylene glycerol ether, polyoxypropylene polyoxyethylene glycerol ether, and polydimethylsiloxane.

4. The method for preparing a biodegradable green printing ink according to claim 1, wherein: The leveling agent is one of polydimethylsiloxane, polymethylalkylsiloxane, polyether polyester modified organic siloxane, alkyl modified organic siloxane and polyether modified dimethylpolysiloxane.

5. The method for preparing a biodegradable green printing ink according to claim 1, characterized in that: The surfactant is one of sodium dodecylbenzenesulfonate, sulfated castor oil, dioctyl sodium succinate sulfonate, sodium glycocholate, sodium oleate and sodium ligninsulfonate.