CN-121976427-A - Environment-friendly polylactic acid coating liquid and preparation method thereof, and composite packaging paper and preparation method thereof

Abstract

The invention discloses an environment-friendly polylactic acid coating liquid and a preparation method thereof, and a composite packaging paper and a preparation method thereof, which comprises solute polylactic acid and solvent dipropylene glycol dimethyl ether, and dissolving the polylactic acid in the dipropylene glycol dimethyl ether to obtain the degradable polylactic acid coating liquid for coating the paper-based material. And coating the polylactic acid coating liquid on at least one surface of the paper-based material to form a coating, so as to obtain the degradable high-performance composite packaging paper. The invention adopts the low-toxicity and low-VOC solvent DMM, thereby fundamentally eliminating the harm of the traditional toxic solvent to personnel and environment, and the physical strength, the hydrophobicity, the barrier property and the like of the coated composite paper are better improved.

Inventors

• GUAN XIUQIONG
• LIU CHUN
• HE JIE

Assignees

• 四川轻化工大学

Dates

Publication Date

20260505

Application Date

20260128

Claims (10)

1. 1. An environment-friendly polylactic acid coating liquid is characterized by comprising a solute and a solvent; the solute is polylactic acid; the solvent is dipropylene glycol dimethyl ether; And dissolving the polylactic acid in the dipropylene glycol dimethyl ether to obtain the degradable polylactic acid coating liquid for coating the paper-based material.
2. 2. The environment-friendly polylactic acid coating liquid according to claim 1, wherein the ratio of the polylactic acid to the dipropylene glycol dimethyl ether is in a range of 2-3 g of solute to 50 ml of solvent.
3. 3. The environmentally friendly polylactic acid coating liquid according to claim 1, further comprising an antibacterial and antifungal agent added thereto.
4. 4. The preparation method of the environment-friendly polylactic acid coating liquid is characterized by comprising the following steps: adding the polylactic acid into the dipropylene glycol dimethyl ether, and heating; the heating temperature is 90-98 ℃, namely under the condition of the dissolving temperature, solute polylactic acid is dissolved in solvent dipropylene glycol dimethyl ether; and stirring in the dissolving process to obtain transparent coating liquid.
5. 5. The method for producing an environmentally friendly polylactic acid coating liquid according to claim 4, wherein the dissolution temperature is selected to be 96 ℃.
6. 6. The method for preparing an environment-friendly polylactic acid coating liquid according to claim 4, wherein the heating mode is water bath heating.
7. 7. The utility model provides a high performance composite packaging paper which characterized in that: the environment-friendly polylactic acid coating liquid according to any one of claims 1-3 is covered on at least one surface of a paper base material to form a coating layer, so that the degradable high-performance composite packaging paper is obtained.
8. 8. The high performance composite wrapper of claim 7, wherein the paper based material is a steam cracker slurry sheet.
9. 9. The preparation method of the degradable polylactic acid coated steam cracker slurry packing paper based on the environment-friendly solvent dipropylene glycol dimethyl ether is characterized by comprising the following steps: The preparation of a base material, namely, the quantification of a paper sheet of the steam cracker is 95-100 g.m -2 ; coating the coating liquid according to any one of claims 1-3 on the surface of a paper sheet uniformly and double-sided by using a bar coater, wherein the coating weight is 7-8g/m 2 ; Drying and curing, namely placing the coated paper in a drum dryer after coating is finished, drying for 9-10 minutes at 103-105 ℃, and then hot-pressing for 4.8-5 minutes at 1.9-2 MPa and 168-170 ℃ to form the coated paper.
10. 10. The preparation method of the degradable polylactic acid coated steam cracker slurry packaging paper based on the environment-friendly solvent dipropylene glycol dimethyl ether, which is disclosed in claim 9, is characterized in that the coating liquid is added with 0.08-0.1% of organic antibacterial mildew inhibitor by mass percent.

Description

Environment-friendly polylactic acid coating liquid and preparation method thereof, and composite packaging paper and preparation method thereof Technical Field The invention relates to the technical field of biomass materials and environment-friendly coatings, in particular to a degradable polylactic acid coating based on an environment-friendly solvent dipropylene glycol dimethyl ether and a steam cracker slurry packaging paper prepared by coating. Background Currently, methylene chloride, chloroform, and the like are widely used as solvents for polylactic acid coating solutions. These solvents are toxic, volatile, and carcinogenic and pose a serious threat to the health of production operators. The production process has the problem of high VOC emission, and is not friendly to the environment. Solvent residues easily appear in the finished product, and the application of the product in the fields with high safety requirements such as food packaging, high-end electronics and the like is limited. The paper coating is prepared by adopting methylene dichloride as a solvent in the literature on study of improving the moisture permeability of paper by using a hydrophobic modified nano cellulose/polylactic acid composite material, the paint of the hydrophobic antibacterial food packaging paper by adopting trichloromethane-dissolved polylactic acid in the literature on preparation of the polylactic acid-nano zinc oxide composite hydrophobic antibacterial food packaging paper and application of the polylactic acid-nano zinc oxide composite hydrophobic antibacterial food packaging paper in fresh meat preservation, and the patent CN112647356A adopts trichloromethane as a polylactic acid solvent to prepare the food packaging paper. In the related literature and patent, dichloromethane or chloroform is used as a polylactic acid coating solvent, and is a Volatile Organic Compound (VOC), and a large amount of Volatile Organic Compound (VOC) is volatilized into the air in the coating and drying processes, so that injury and environmental hazard are caused to personnel, and the solvent belongs to ODS (ozone depletion substances), and the GWP (high global warming potential) of the dichloromethane is high, so that the solvent is a strong greenhouse gas. The paper-based material is modified in such a way that the pure paper-based material (such as the steam cracker pulp paper) has the problems of insufficient strength, hydrophobicity, barrier property and the like, and the application of the paper-based material needs to be expanded through coating modification. Meanwhile, the market has an increasing demand for biodegradable, green and environment-friendly packaging materials. In summary, the present invention aims to solve the technical problems of poor safety and great environmental pollution caused by the use of toxic solvents in the existing polylactic acid coating liquid. Meanwhile, a green coating solution capable of remarkably improving physical strength, hydrophobicity and barrier property of the paper-based material is provided, and the paper-based material is endowed with the additional functions of biodegradability, bacteriostasis and the like. Disclosure of Invention The invention discloses an environment-friendly polylactic acid coating liquid and a preparation method thereof, and a composite packaging paper and a preparation method thereof, and aims to provide a polylactic acid (PLA) coating liquid prepared by using a low-toxicity and low-VOC (volatile organic compound) organic solvent dipropylene glycol dimethyl ether (DMM) and a biodegradable high-performance composite packaging paper material obtained by coating steam exploded bamboo pulp paper by using the coating liquid. In view of the foregoing problems of the prior art, according to one aspect of the disclosure, the present invention adopts the following technical solutions: an environment-friendly polylactic acid coating liquid comprises a solute and a solvent; the solute is polylactic acid; the solvent is dipropylene glycol dimethyl ether; And dissolving the polylactic acid in the dipropylene glycol dimethyl ether to obtain the degradable polylactic acid coating liquid for coating the paper-based material. In order to better realize the invention, the further technical scheme is as follows: further, the ratio range of the polylactic acid to the dipropylene glycol dimethyl ether is 50 milliliters of solvent corresponding to 2-3 grams of solute. Further, the antibacterial mildew inhibitor is added into the water-soluble antibacterial mildew inhibitor. The invention can also be: A method for preparing environment-friendly polylactic acid coating liquid, which comprises the following steps: adding the polylactic acid into the dipropylene glycol dimethyl ether, and heating; The heating temperature is 90-98 ℃, namely, under the condition of the dissolving temperature, the solute polylactic acid is dissolved in the solvent dipropylene glycol dimethyl ether;