PBAT or / and PLA dispersion and preparation method thereof, preparation method of barrier coating liquid, prepared coating liquid and application of coating liquid

Abstract

According to the PBAT or / and PLA dispersion and the preparation method thereof, the preparation method of the barrier coating liquid, the prepared coating liquid and the application of the barrier coating liquid, the PBAT or / and PLA dispersion provided by the invention is relatively safe in preparation process and application due to the fact that the used dispersing agent is only composed of ethanol, propylene glycol, glycerol and 1, 3-butanediol and does not need other auxiliaries; the prepared barrier coating liquid is used for preparing a coating, is water-based bio-based and degradable, and has waterproof and oil-proof characteristics. The problems that the waterproof performance cannot be achieved or can be achieved only after being complex and solvents are unhealthy in the prior art are solved.

Description

Technical Field

[0001] This invention relates to the fields of aqueous dispersions and coatings, and more particularly to a PBAT or / and PLA dispersion, a method for preparing the same, a method for preparing a barrier coating liquid, the resulting coating liquid, and its application. Background Technology

[0002] With the gradual implementation of global policies banning or restricting plastics, the replacement of plastics with paper has entered a period of rapid development. As a result, traditional food packaging materials such as coated paper and waxed paper are gradually being abandoned due to their disadvantages, such as difficulty in recycling and the difficulty in polymer degradation, which put great pressure on the ecological environment. Therefore, coated paper is receiving increasing attention as a food packaging material.

[0003] Coating is the most basic technology in the manufacture of coated paper and has a crucial impact on the product's application. For food packaging paper, in addition to meeting the requirements of operability and printability during coating operations, the coating must also possess characteristics such as water resistance, oil resistance, antibacterial properties, and safety. Currently, fluorinated water and oil repellents are commonly used to achieve water and oil barrier properties, such as fluorinated modified acrylic emulsions. However, these modified emulsions pose potential health hazards to humans.

[0004] The existing technology CN116623459B, "A method for preparing biodegradable antibacterial chitosan-modified nanocellulose oleophobic paper," has oleophobic and antibacterial properties, but does not have waterproof properties.

[0005] The laminated sheet provided by KR102321693B1 requires two layers, a coating layer and a thin film coating, to be water-resistant; moreover, the solvents used in the coating layer, dichloromethane and chloroform, are toxic and pose health risks. Summary of the Invention

[0006] To address the risks associated with existing waterproofing technologies that either fail to achieve the desired performance or require complex methods and employ unhealthy solvents, this application provides a PBAT or / and PLA dispersion, its preparation method, a barrier coating preparation method, the resulting coating, and its application. The PBAT or / and PLA dispersion provided in this application uses only ethanol, propylene glycol, glycerol, and 1,3-butanediol as dispersants, requiring no other additives, making its preparation and application relatively safe. The prepared barrier coating, used to form a coating layer, is water-based, biodegradable, and possesses both waterproof and oil-repellent properties.

[0007] The object of this invention is achieved by the following means: a PBAT or / and PLA dispersion comprising: (1) a dispersed phase, wherein the dispersed phase is polybutylene adipate / terephthalate, polylactic acid, or a mixture thereof, wherein the particle size of the polybutylene adipate / terephthalate and the polylactic acid is 40-200 mesh; and (2) a dispersant, wherein the dispersant is composed of ethanol, propylene glycol, glycerol, and 1,3-butanediol. PBAT is polybutylene adipate / terephthalate, and PLA is polylactic acid.

[0008] The ratio of dispersed phase to dispersant is 20-35:20-40. The dispersant is composed of the following raw materials in parts by weight: 0-20 parts ethanol, 5-60 parts propylene glycol, 5-60 parts glycerol, and 5-60 parts 1,3-butanediol. The molecular weight of poly(butylene adipate) / poly(terephthalate) is 10,000-30,000; the molecular weight of polylactic acid is 10,000-50,000.

[0009] Add the dispersed phase to the dispersant, heat and stir until PBAT / PLA is completely dispersed.

[0010] The method for preparing the poly(adipate) / butylene terephthalate and / or polylactic acid dispersion involves adding the dispersed phase to a dispersant, heating to 80-150°C, and stirring at 100-200 r / min for 10-20 min until completely dispersed. A method for preparing a barrier coating liquid includes the following steps: (1) Add 3-10 parts of poly(butylene adipate) / butylene terephthalate to 20-40 parts of dispersant, heat to 80-130 ℃, and stir at 100-200 r / min for 10-20 min until completely dispersed or dissolved; the dispersant is composed of the following raw materials in parts by weight: 0-20 parts of ethanol, 5-60 parts of propylene glycol, 5-60 parts of glycerol, and 5-60 parts of 1,3-butanediol; the particle size of poly(butylene adipate) / butylene terephthalate and polylactic acid is 40-200 mesh; (2) Continue to add 10-30 parts of polylactic acid and stir for 10-20 min at a speed of 100-200 r / min; (2) Cool down to 60-80 ℃, add 60-120 parts of water, and continue stirring for 10-20 min at a speed of 100-200 r / min; (3) Then add 1-5 parts of carboxymethyl cellulose and 1-5 parts of chitosan, and stir at 100-200 r / min for 10-20 min; (4) Then add 20-80 parts of cationic modified cellulose nanofibers, stir at 150-500 r / min for 10-30 min, and cool to room temperature to obtain the product.

[0011] Cationic modified cellulose nanofibers with diameters of 5-100 nm, aspect ratios ≥100, charge ≥0.2 mmol / g, and zeta potential ≥ +30 mV; The molecular weight of poly(butylene adipate) terephthalate is 10,000-30,000; the molecular weight of polylactic acid is 10,000-50,000. The degree of deacetylation of chitosan is 75-90%; The water is deionized.

[0012] A barrier coating liquid, wherein the barrier coating liquid is prepared by the method described above, and the barrier coating liquid is a water-based biodegradable waterproof and oil-resistant barrier coating liquid.

[0013] The application of the aforementioned barrier coating liquid.

[0014] A coated paper having a waterproof and oil-repellent layer, wherein the waterproof and oil-repellent layer is the aforementioned barrier coating liquid after drying, and the coating amount is 3-10 g / m². 2 .

[0015] Compared with the prior art, this application provides a PBAT or / and PLA dispersion and its preparation method, as well as a barrier coating preparation method, the obtained coating, and its application. Since the dispersant used consists only of ethanol, propylene glycol, glycerol, and 1,3-butanediol, and no other additives are required, the preparation process and application are relatively safe. The prepared barrier coating is used to make a coating that is water-based, biodegradable, and has waterproof and oil-proof properties.

[0016] In this invention, heating is performed during the preparation of the barrier coating liquid to soften and disperse PBAT and PLA, making it easier for them to adhere / combine with other raw materials in the coating liquid, thereby forming a relatively uniform coating liquid. This results in a coating with good waterproof, oil-proof, tensile strength, and burst resistance.

[0017] In the coating solution provided by this invention, PBAT, PLA, and CMC exhibit excellent film-forming properties, CS provides good antibacterial properties, and CCNF offers excellent strength properties for the coating. Furthermore, CMC provides good adhesion to the coating, while the positive charge of CCNF allows the coating to be firmly anchored to the paper surface. After treatment with the barrier coating of this invention, the paper's water and oil resistance, as well as its strength, are significantly improved. Untreated base paper (filter paper) Cobb 60 With a value of 100, its oil resistance is grade 0. After applying the barrier coating, its Cobb... 60 The oil resistance rating and oil resistance level can reach up to 7.0 g / m.2 With a strength rating of 11, it offers excellent waterproof and oil-proof properties. Simultaneously, the paper's strength properties are significantly improved, with tensile strength and burst strength increasing by over 15%. Furthermore, the barrier coating dissolves rapidly in aqueous environments at certain temperatures and completely degrades within 30 days in natural environments (soil landfill method). This means the barrier coating does not affect the reuse of the original paper or the natural environment, making it a green and environmentally friendly coating. Detailed Implementation

[0018] A PBAT and / or PLA dispersion comprising: (1) a dispersed phase, wherein the dispersed phase is polybutylene adipate / terephthalate, polylactic acid, or a mixture of both, wherein the particle size of the polybutylene adipate / terephthalate and the polylactic acid is 40-200 mesh; and (2) a dispersant, wherein the dispersant is composed of ethanol, propylene glycol, glycerol, and 1,3-butanediol. PBAT is polybutylene adipate / terephthalate, and PLA is polylactic acid.

[0019] The ratio of dispersed phase to dispersant is 20-35:20-40.

[0020] The dispersant is composed of the following raw materials in parts by weight: 0-20 parts ethanol, 5-60 parts propylene glycol, 5-60 parts glycerol, and 5-60 parts 1,3-butanediol.

[0021] The molecular weight of poly(butylene adipate) / poly(terephthalate) is 10,000-30,000; the molecular weight of polylactic acid is 10,000-50,000.

[0022] Add the dispersed phase to the dispersant, heat and stir until PBAT / PLA is completely dispersed.

[0023] The method for preparing the poly(adipate) / butylene terephthalate and / or polylactic acid dispersion involves adding the dispersed phase to a dispersant, heating to 80-150°C, and stirring at 100-200 r / min for 10-20 min until completely dispersed. A method for preparing a barrier coating liquid includes the following steps: (1) Add 3-10 parts of poly(butylene adipate / terephthalate) to 20-40 parts of dispersant, heat to 80-130 ℃, and stir at 100-200 r / min for 10-20 min until completely dispersed; the dispersant is composed of the following raw materials by weight: 0-20 parts of ethanol, 5-60 parts of propylene glycol, 5-60 parts of glycerol, and 5-60 parts of 1,3-butanediol; the particle size of poly(butylene adipate / terephthalate) and polylactic acid is 40-200 mesh; (2) Continue to add 10-30 parts of polylactic acid and stir for 10-20 min at a speed of 100-200 r / min; (2) Cool down to 60-80 ℃, add 60-120 parts of water, and continue stirring for 10-20 min at a speed of 100-200 r / min; (3) Then add 1-5 parts of carboxymethyl cellulose and 1-5 parts of chitosan, and stir at 100-200 r / min for 10-20 min; (4) Then add 20-80 parts of cationic modified cellulose nanofibers, stir at 150-500 r / min for 10-30 min, and cool to room temperature to obtain the product; Cationic modified cellulose nanofibers with diameters of 5-100 nm, aspect ratios ≥100, charge ≥0.2 mmol / g, and zeta potential ≥ +30 mV; The molecular weight of poly(butylene adipate) terephthalate is 10,000-30,000. The molecular weight of polylactic acid is 10,000-50,000; The degree of deacetylation of chitosan is 75-90%; The water is deionized.

[0024] A barrier coating liquid, wherein the barrier coating liquid is prepared by the method described above, and the barrier coating liquid is a water-based biodegradable waterproof and oil-resistant barrier coating liquid.

[0025] The application of the aforementioned barrier coating liquid.

[0026] A coated paper having a waterproof and oil-repellent layer, wherein the waterproof and oil-repellent layer is the aforementioned barrier coating liquid after drying, and the coating amount is 3-10 g / m². 2 .

[0027] The present invention will now be described in detail with reference to specific embodiments. It should be noted that these embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments based on the above description of the present invention.

[0028] The cationic modified cellulose nanofibers (CCNF) used in this application are: CellubYo / Cellunano, model CNF-QC1, with surface groups: quaternary ammonium salt groups, surface group content 0.06%; diameter 5-10 nm, length over 1000 nm, and solid content 1-2%. PBAT has a molecular weight of 10,000-30,000; PLA has a molecular weight of 10,000-50,000; and CS has a degree of deacetylation of 75-90%. Polybutylene adipate / terephthalate (PBAT), polylactic acid (PLA), carboxymethyl cellulose (CMC), and chitosan are all commercially available general-purpose products.

[0029] Example 1: A method for preparing a barrier coating liquid, comprising the following raw materials in parts by weight: 40 parts of cationic modified cellulose nanofibers (CCNF), 20 parts of dispersant, 5 parts of polybutylene adipate / terephthalate (PBAT), 15 parts of polylactic acid (PLA), 3 parts of carboxymethyl cellulose (CMC), 2 parts of chitosan (CS), and 100 parts of deionized water; the dispersant is composed of the following raw materials in parts by weight: 5 parts of ethanol, 30 parts of propylene glycol, 5 parts of glycerol, and 60 parts of 1,3-butanediol.

[0030] (1) Place PBAT and PLA into a pulverizer and pulverize them for a short time multiple times to obtain powder with a particle size of 40 mesh; (2) Mix PBAT and dispersant, heat to 95°C, and continue stirring at 200 r / min for 20 min until completely mixed and dispersed; (3) Add PLA and continue stirring at 200 r / min for 15 min; (4) Cool down to 70 °C, add deionized water, and continue stirring for 10 min at a speed of 150 r / min; (5) Add CMC and CS, and stir at 150 r / min for 10 min; (6) Add CCNF, stir at 300 r / min for 30 min, and cool to room temperature to obtain the product.

[0031] Example 2 A method for preparing a barrier coating liquid, comprising the following raw materials in parts by weight: 80 parts of cationic modified cellulose nanofibers (CCNF), 25 parts of dispersant, 3 parts of polybutylene adipate / terephthalate (PBAT), 20 parts of polylactic acid (PLA), 1 part of carboxymethyl cellulose (CMC), 5 parts of chitosan (CS), and 60 parts of deionized water; the dispersant is composed of the following raw materials in parts by weight: 0 parts of ethanol, 60 parts of propylene glycol, 20 parts of glycerol, and 20 parts of 1,3-butanediol.

[0032] (1) Place PBAT and PLA into a pulverizer and pulverize them for a short time multiple times to obtain powder with a particle size of 80 mesh; (2) Mix PBAT and dispersant, heat to 100 °C, and continue stirring at 200 r / min for 15 min until completely dissolved; (3) Add PLA and continue stirring at 150 r / min for 20 min; (4) Cool down to 70 °C, add deionized water, and continue stirring for 15 min at a speed of 150 r / min; (5) Add CMC and CS, and stir at 150 r / min for 15 min; (6) Add CCNF, stir at 350 r / min for 15 min, and cool to room temperature to obtain the product.

[0033] Example 3: A method for preparing a barrier coating liquid, comprising the following raw materials in parts by weight: 60 parts of cationic modified cellulose nanofibers (CCNF), 30 parts of dispersant, 10 parts of polybutylene adipate / terephthalate (PBAT), 20 parts of polylactic acid (PLA), 5 parts of carboxymethyl cellulose (CMC), 3 parts of chitosan (CS), and 80 parts of deionized water; the dispersant is composed of the following raw materials in parts by weight: 20 parts of ethanol, 5 parts of propylene glycol, 60 parts of glycerol, and 15 parts of 1,3-butanediol.

[0034] (1) Place PBAT and PLA into a pulverizer and pulverize them for a short time multiple times to obtain powder with a particle size of 100 mesh; (2) Mix PBAT and dispersant, heat to 130 °C, and continue stirring at 180 r / min for 15 min until completely dissolved; (3) Add PLA and continue stirring at 200 r / min for 20 min; (4) Cool down to 80 °C, add deionized water, and continue stirring for 12 min at a speed of 200 r / min; (5) Add CMC and CS, and stir at 150 r / min for 10 min; (6) Add CCNF, stir at 400 r / min for 20 min, and cool to room temperature to obtain the product.

[0035] Example 4: A method for preparing a barrier coating liquid, comprising the following raw materials in parts by weight: 30 parts of cationic modified cellulose nanofibers (CCNF), 40 parts of dispersant, 5 parts of polybutylene adipate / terephthalate (PBAT), 30 parts of polylactic acid (PLA), 1 part of carboxymethyl cellulose (CMC), 3 parts of chitosan (CS), and 120 parts of deionized water; the dispersant is composed of the following raw materials in parts by weight: 20 parts of ethanol, 40 parts of propylene glycol, 35 parts of glycerol, and 5 parts of 1,3-butanediol.

[0036] (1) Place PBAT and PLA into a pulverizer and pulverize them for a short time multiple times to obtain powder with a particle size of 100 mesh; (2) Mix PBAT and dispersant, heat to 130 °C, and continue stirring at 100 r / min for 15 min until completely dissolved; (3) Add PLA and continue stirring at 150 r / min for 20 min; (4) Cool down to 80 °C, add deionized water, and continue stirring for 10 min at a speed of 200 r / min; (5) Add CMC and CS, and stir at 200 r / min for 10 min; (6) Add CCNF, stir at 500 r / min for 10 min, and cool to room temperature to obtain the product.

[0037] Qualitative filter paper was used as the untreated base paper. It was coated (sized) with the coating solution described in the above example and dried at 105°C. Its water absorption was determined by the Cobb method of GB / T 1540-2002, its grease resistance (oil resistance grade) was determined by GB / T 22805.2-2008, its tensile strength was determined by GB / T 12914-2008, and its bursting strength was determined by GB / T 454-2020. The test results are shown in Table 1.

[0038] Table 1. Water and oil repellency properties of novel water-based biodegradable waterproof and oil-repellent barrier coatings The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. It should be noted that for those skilled in the art and any person skilled in the art, any equivalent substitutions or changes made to the technical solution and inventive concept of the present invention without departing from the overall concept of the present invention, as well as any changes and improvements made, should also be considered within the scope of protection of the present invention.

Claims

1. A PBAT and / or PLA dispersion, characterized in that: PBAT is polybutylene adipate / terephthalate, and PLA is polylactic acid; the dispersion contains: (1) a dispersed phase, which is polybutylene adipate / terephthalate, polylactic acid, or a mixture of the two, with the particle size of polybutylene adipate / terephthalate and polylactic acid being 40-200 mesh; (2) a dispersant, which is composed of ethanol, propylene glycol, glycerol, and 1,3-butanediol.

2. The PBAT or / and PLA dispersion according to claim 1, characterized in that: The ratio of dispersed phase to dispersant is 20-35:20-40; The dispersant is composed of the following raw materials in parts by weight: 0-20 parts ethanol, 5-60 parts propylene glycol, 5-60 parts glycerol, and 5-60 parts 1,3-butanediol. The molecular weight of poly(butylene adipate) / poly(terephthalate) is 10,000-30,000; the molecular weight of polylactic acid is 10,000-50,000.

3. The method for preparing PBAT and / or PLA dispersions according to claim 1 or 2, characterized in that: Add the dispersed phase to the dispersant, heat and stir until PBAT / PLA is completely dispersed.

4. The method for preparing PBAT or / and PLA dispersions according to claim 3, characterized in that: Add the dispersed phase to the dispersant, heat to 80-130 ℃, and stir at 100-200 r / min for 10-20 min until completely dispersed.

5. A method for preparing a barrier coating liquid, characterized in that: Includes the following steps, (1) Add 3-10 parts of poly(adipate) / butylene terephthalate to 20-40 parts of dispersant, heat to 80-130℃, and stir at 100-200 r / min for 10-20 min until completely dispersed; The dispersant is composed of the following raw materials in parts by weight: 0-20 parts ethanol, 5-60 parts propylene glycol, 5-60 parts glycerol, 5-60 parts 1,3-butanediol; and poly(butylene adipate / terephthalate) and polylactic acid with a particle size of 40-200 mesh. (2) Continue to add 10-30 parts of polylactic acid and stir for 10-20 min at a speed of 100-200 r / min; (2) Cool down to 60-80 ℃, add 60-120 parts of water, and continue stirring for 10-20 min at a speed of 100-200 r / min; (3) Then add 1-5 parts of carboxymethyl cellulose and 1-5 parts of chitosan, and stir at 100-200 r / min for 10-20 min; (4) Then add 20-80 parts of cationic modified cellulose nanofibers, stir at 150-500 r / min for 10-30 min, and cool to room temperature to obtain the final product.

6. The method for preparing the barrier coating liquid according to claim 5, characterized in that: Cationic modified cellulose nanofibers with diameters of 5-100 nm, aspect ratios ≥100, charge ≥0.2 mmol / g, and zeta potential ≥ +30 mV; The molecular weight of poly(butylene adipate) terephthalate is 10,000-30,000; the molecular weight of polylactic acid is 10,000-50,000. The degree of deacetylation of chitosan is 75-90%; The water is deionized.

7. A barrier coating liquid, characterized in that: The barrier coating is prepared by the method described in claim 5, and the barrier coating is a water-based biodegradable waterproof and oil-resistant barrier coating.

8. The application of the barrier coating liquid according to claim 7.

9. A coated paper having a waterproof and oil-repellent layer, wherein the waterproof and oil-repellent layer is the barrier coating liquid according to claim 7 of this application after drying, and the coating amount is 3-10 g / m². 2 .

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