Preparation method of waterproof and oilproof paper-based material containing composite coating

Abstract

The invention discloses a preparation method of a waterproof and oilproof paper-based material containing a composite coating, and belongs to the technical field of packaging papers.The preparation method comprises the following steps that S1, a sodium alginate aqueous solution is prepared, and a coating A is obtained; s2, preparing a PLA and PBAT mixed solution to obtain a coating B; s3, uniformly coating the surface of raw kraft paper with the coating A, and then performing drying and hot pressing to obtain dry raw kraft paper with a flat surface; and S4, uniformly coating the coating B on the surface of the kraft base paper coated with the coating A, and fully drying to obtain the waterproof and oilproof paper-based material containing the sodium alginate, PLA and PBAT composite coating. The water-proof and oil-proof paper-based material prepared by the invention not only remarkably improves the water-proof and oil-proof performance of paper, but also retains the biodegradable characteristic of the paper, and has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of packaging paper, and in particular relates to a method for preparing a waterproof and oil-proof paper-based material containing a composite coating. Background Art

[0002] Waterproof and oil-proof paper is a paper-based material with special functions. It has good barrier properties against both water and oil and is widely used in packaging, protection and other fields. Paper and cardboard, as the two basic materials in the packaging field, are widely used in the packaging of various products due to their strong plasticity, low cost and easy processing. However, the inherent porous structure and hydrophilic properties of the fibers of these two types of materials make them obviously insufficient in terms of water resistance and oil resistance. This deficiency limits their application to a certain extent under specific packaging requirements, especially in application scenarios that require moisture and oil resistance.

[0003] In order to give paper materials waterproof and oil-proof properties, it is usually necessary to treat the paper materials or add specific additives to enhance their waterproof and oil-proof properties. At present, there are two main methods for waterproof and oil-proof treatment of paper materials. The first method is to cover the surface of the paper with a layer of waterproof and oil-proof plastic (commonly known as lamination or plastic coating). Although this method can effectively improve the waterproof and oil-proof ability of paper, it only reduces the degree of plastic pollution and does not fundamentally solve the problem of plastic pollution. In contrast, the second method is to apply a waterproof and oil-proof coating on the surface of the paper to achieve a waterproof and oil-proof effect. This method not only gives the paper good waterproof and oil-proof properties, but also retains the biodegradability of the paper and the environmental advantages of recycling and reuse to the greatest extent.

[0004] However, the current single coating has poor water and oil resistance, which is difficult to meet the water and oil resistance requirements of paper-based packaging materials. Therefore, the development of environmentally friendly water and oil-proof paper-based barrier materials has become an urgent problem to be solved in the paper packaging industry. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a method for preparing a waterproof and oil-proof paper-based material containing a composite coating, which can obtain a paper-based material with high waterproof and oil-proof properties, effectively extend the service life of the packaged items, while maintaining the environmental protection characteristics of the material, and meet the market demand for high-performance, environmentally friendly packaging materials.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing a waterproof and oil-proof paper-based material containing a composite coating, comprising the following steps:

[0008] S1, preparing a sodium alginate aqueous solution to obtain coating A;

[0009] S2, preparing a mixed solution of PLA and PBAT to obtain coating B;

[0010] S3, coating the coating A evenly on the surface of the kraft paper, and then drying and hot pressing to obtain a dry kraft paper with a smooth surface;

[0011] S4. Coating B evenly on the surface of kraft paper coated with coating A, and fully drying, thereby obtaining a waterproof and oil-proof paper-based material containing a composite coating of sodium alginate, PLA and PBAT.

[0012] Preferably, in step S1, the mass volume percentage concentration of the sodium alginate aqueous solution is 1% to 4%.

[0013] Preferably, the sodium alginate aqueous solution is prepared by pouring weighed deionized water into a beaker, placing the beaker in a 45° C. water bath, pouring a certain mass of sodium alginate under magnetic stirring, stirring for 1 hour, and obtaining a sodium alginate solution with a mass volume percentage concentration of 1% to 4%.

[0014] Preferably, in step S2, the mass volume percentage concentration of the PLA and PBAT mixed solution is 5% to 15%.

[0015] Preferably, the preparation method of the PLA and PBAT mixed solution is: weigh PLA and PBAT particles according to a certain ratio, pour them into a reagent bottle, add a solvent, shake them in a 45°C water bath for 4 hours to fully dissolve them, let them stand to eliminate bubbles, and obtain a PLA and PBAT mixed solution with a mass volume percentage concentration of 5% to 15%.

[0016] Preferably, the mass ratio of PLA and PBAT weighed is 5:1-10.

[0017] Preferably, the solvent is one of dichloromethane and chloroform.

[0018] Preferably, in step S3, the kraft paper coated with coating A is dried in an oven at 105°C for 2 minutes, and then hot-pressed at a temperature of 105°C and a pressure of about 0.2 kPa for 1 minute to obtain a dry kraft paper with a smooth surface.

[0019] Preferably, in step S3, the coating amount of coating A is controlled to be 1-4 g / m 2 In step S4, the coating amount of coating B is controlled to 3-10g / m 2 ; The total coating amount is controlled to 1-13g / m 2 .

[0020] By adopting the above technology, the beneficial effects of the present invention are as follows:

[0021] 1. The present invention uses sodium alginate, PLA and PBAT as anti-oil functional components, and prepares a coating with strong waterproof and oil-proof performance by compounding the three components. The coating can greatly improve the waterproof and oil-proof performance of coated paper and improve the application value of paper.

[0022] 2. Sodium alginate is a natural polysaccharide that can be extracted from seaweed. PLA and PBAT are both new biodegradable materials, and PBAT can significantly improve the toughness of PLA. Coating the three raw materials on paper can improve the water and oil resistance of the paper while retaining its biodegradable properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0024] Figure 1 A schematic flow chart of a method for preparing a waterproof and oil-proof paper-based material containing a composite coating provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiment of the present invention. It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those generally understood by ordinary technicians in the technical field to which the present invention belongs.

[0026] The kraft paper used in the examples was sourced from Guangzhou Paper Group Co., Ltd., with a basis weight of 70 g / m 2 , A4 paper size. Kraft paper base paper oil proof grade 0, cobb 60 82.8g / m 2 .

[0027] Example 1

[0028] ⑴ Weigh 98.5g of distilled water and pour it into a beaker. Place the beaker in a 45℃ water bath and stir it magnetically. Weigh 1.5g of sodium alginate and slowly pour it into the beaker. After it is completely poured in, seal the beaker, stir it in the water bath for 1h, take it out, and let it stand.

[0029] ⑵ According to the ratio of 5:1, weigh 5g of PLA and PBAT in total, pour them into a wide-mouth bottle, add 45g of chloroform into the bottle, cover the bottle cap, place it in a 45℃ water bath and shake for 4h, take it out and let it stand for use.

[0030] ⑶ Evenly coat the sodium alginate solution on the surface of kraft paper, dry it in an oven at 105°C for 2 minutes, and then hot press it at 105°C and a pressure of about 0.2kPa for 1 minute to make the coated paper dry and smooth. The coating amount is about 1.5g / m 2 .

[0031] ⑷ The PLA and PBAT mixed solution is evenly coated on the surface of the coated kraft paper obtained in step ⑶, and the coated paper is placed in a fume hood to be fully dried to obtain a waterproof and oil-proof paper-based material containing a composite coating of sodium alginate, PLA and PBAT. The total coating amount is about 7.5g / m 2 .

[0032] Result: The obtained waterproof and oil-proof paper has an oil-proof grade of 12, cobb 60 0.84g / m 2 .

[0033] Example 2

[0034] ⑴ Weigh 98.5g of distilled water and pour it into a beaker. Place the beaker in a 45℃ water bath and stir it magnetically. Weigh 1.5g of sodium alginate and slowly pour it into the beaker. After it is completely poured in, seal the beaker, stir it in the water bath for 1h, take it out, and let it stand.

[0035] ⑵ According to the ratio of 5:2, weigh 5g of PLA and PBAT in total, pour them into a wide-mouth bottle, add 45g of chloroform into the bottle, cover the bottle cap, place it in a 45℃ water bath and shake for 4h, take it out and let it stand for use.

[0036] ⑶ Evenly coat the sodium alginate solution on the surface of kraft paper, dry it in an oven at 105°C for 2 minutes, and then hot press it at 105°C and a pressure of about 0.2kPa for 1 minute to make the coated paper dry and smooth. The coating amount is about 1.5g / m 2 .

[0037] ⑷ The PLA and PBAT mixed solution is evenly coated on the surface of the coated kraft paper obtained in step ⑶, and the coated paper is placed in a fume hood to be fully dried to obtain a waterproof and oil-proof paper-based material containing a composite coating of sodium alginate, PLA and PBAT. The total coating amount is about 7.5g / m 2 .

[0038] Result: The obtained waterproof and oil-proof paper has an oil-proof grade of 12, cobb 60 0.91g / m 2 .

[0039] Example 3

[0040] ⑴ Weigh 98.5g of distilled water and pour it into a beaker. Place the beaker in a 45℃ water bath and stir it magnetically. Weigh 1.5g of sodium alginate and slowly pour it into the beaker. After it is completely poured in, seal the beaker, stir it in the water bath for 1h, take it out, and let it stand.

[0041] ⑵ According to the ratio of 5:3, weigh 5g of PLA and PBAT in total, pour them into a wide-mouth bottle, add 45g of chloroform into the bottle, cover the bottle cap, place it in a 45℃ water bath and shake for 4h, take it out and let it stand for use.

[0042] ⑶ Evenly coat the sodium alginate solution on the surface of kraft paper, dry it in an oven at 105°C for 2 minutes, and then hot press it at 105°C and a pressure of about 0.2kPa for 1 minute to make the coated paper dry and smooth. The coating amount is about 1.5g / m 2 .

[0043] ⑷ The PLA and PBAT mixed solution is evenly coated on the surface of the coated kraft paper obtained in step ⑶, and the coated paper is placed in a fume hood to be fully dried to obtain a waterproof and oil-proof paper-based material containing a composite coating of sodium alginate, PLA and PBAT. The total coating amount is about 7.5g / m 2 .

[0044] Result: The obtained waterproof and oil-proof paper has an oil-proof grade of 12, cobb 60 0.89g / m 2 .

[0045] Example 4

[0046] ⑴ Weigh 98.5g of distilled water and pour it into a beaker. Place the beaker in a 45℃ water bath and stir it magnetically. Weigh 1.5g of sodium alginate and slowly pour it into the beaker. After it is completely poured in, seal the beaker, stir it in the water bath for 1h, take it out, and let it stand.

[0047] ⑵ According to the ratio of 5:4, weigh 5g of PLA and PBAT, pour them into a wide-mouth bottle, add 45g of chloroform into the bottle, cover the bottle cap, place it in a 45℃ water bath and shake for 4h, take it out and let it stand for use.

[0048] ⑶ Evenly coat the sodium alginate solution on the surface of kraft paper, dry it in an oven at 105°C for 2 minutes, and then hot press it at 105°C and a pressure of about 0.2kPa for 1 minute to make the coated paper dry and smooth. The coating amount is about 1.5g / m 2 .

[0049] ⑷ The PLA and PBAT mixed solution is evenly coated on the surface of the coated kraft paper obtained in step ⑶, and the coated paper is placed in a fume hood to be fully dried to obtain a waterproof and oil-proof paper-based material containing a composite coating of sodium alginate, PLA and PBAT. The total coating amount is about 7.5g / m 2 .

[0050] Result: The obtained waterproof and oil-proof paper has an oil-proof grade of 12, cobb 60 2.19g / m 2 .

[0051] Example 5

[0052] ⑴ Weigh 98.5g of distilled water and pour it into a beaker. Place the beaker in a 45℃ water bath and stir it magnetically. Weigh 1.5g of sodium alginate and slowly pour it into the beaker. After it is completely poured in, seal the beaker, stir it in the water bath for 1h, take it out, and let it stand.

[0053] ⑵ According to the ratio of 5:5, weigh 5g of PLA and PBAT in total, pour them into a wide-mouth bottle, add 45g of chloroform into the bottle, cover the bottle cap, place it in a 45℃ water bath and shake for 4h, take it out and let it stand for use.

[0054] ⑶ Evenly coat the sodium alginate solution on the surface of kraft paper, dry it in an oven at 105°C for 2 minutes, and then hot press it at 105°C and a pressure of about 0.2kPa for 1 minute to make the coated paper dry and smooth. The coating amount is about 1.5g / m 2 .

[0055] ⑷ The PLA and PBAT mixed solution is evenly coated on the surface of the coated kraft paper obtained in step ⑶, and the coated paper is placed in a fume hood to be fully dried to obtain a waterproof and oil-proof paper-based material containing a composite coating of sodium alginate, PLA and PBAT. The total coating amount is about 7.5g / m 2 .

[0056] Result: The obtained waterproof and oil-proof paper has an oil-proof grade of 12, cobb 60 1.64g / m 2 .

[0057] Comparative Example 1

[0058] ⑴ Weigh 98.5g of distilled water and pour it into a beaker. Place the beaker in a 45℃ water bath and stir it magnetically. Weigh 1.5g of sodium alginate and slowly pour it into the beaker. After it is completely poured in, seal the beaker, stir it in the water bath for 1h, take it out, and let it stand.

[0059] ⑵Evenly coat the sodium alginate solution on the surface of kraft paper, dry it in an oven at 105℃ for 2 minutes, and then hot press it at 105℃ and a pressure of about 0.2kPa for 1 minute to make the coated paper dry and smooth. The coating amount is about 1.5g / m 2 .

[0060] Result: The obtained waterproof and oil-proof paper has an oil-proof grade of 3, cobb 60 78.0g / m 2 .

[0061] Comparative Example 2

[0062] ⑴ According to the ratio of 5:1, weigh 5g of PLA and PBAT in total, pour them into a wide-mouth bottle, add 45g of chloroform into the bottle, cover the bottle cap, place it in a 45℃ water bath and shake for 4h, take it out and let it stand for use.

[0063] ⑵Evenly coat the PLA and PBAT mixed solution on the surface of kraft paper, and place the coated paper in a fume hood to fully dry, thus obtaining a waterproof and oil-proof paper-based material containing PLA and PBAT coating. The coating amount is about 6g / m 2 .

[0064] Result: The obtained waterproof and oil-proof paper has an oil-proof grade of 4, cobb 60 3.38g / m 2 .

[0065] By comparing the examples with the comparative examples, it can be clearly seen that the present invention has a significant effect in improving the water and oil resistance of paper. In the examples, through a carefully designed preparation process, the three components of sodium alginate, PLA (polylactic acid) and PBAT (polyethylene terephthalate-co-caprolactone) are effectively compounded together to form a high-performance coating. The coating not only significantly improves the water and oil resistance of kraft paper, making its oil resistance grade reach grade 12, but also cobb 60 The value is also relatively low, indicating that it has good waterproof performance. In addition, with the change of the ratio of PLA to PBAT, the waterproof and oil-proof properties of the coating also show a certain regularity, which provides a basis for further optimization of the formula.

[0066] In contrast, the paper in the comparative example did not show such excellent performance. Comparative Example 1 only used sodium alginate as the coating component. Although sodium alginate is a natural polysaccharide with certain hydrophilicity and film-forming properties, its waterproof and oil-proof effect is limited when used alone, resulting in the oil-proof grade of the obtained paper being only Grade 3. 60 Value up to 78.0g / m 2, the waterproof and oil-proof performance is poor. Comparative Example 2 only uses a mixed solution of PLA and PBAT as the coating. Although both materials are biodegradable materials, they cannot achieve the expected waterproof and oil-proof effect when used alone. The oil-proof grade is only level 4, cobb 60 The value is 3.38g / m 2 .

[0067] In summary, the embodiments of the present invention successfully prepare a high-performance waterproof and oil-proof paper-based material by cleverly combining the three components of sodium alginate, PLA and PBAT, which not only significantly improves the waterproof and oil-proof properties of paper, but also retains its biodegradable properties, and has broad application prospects.

[0068] The above is a detailed introduction to the preparation method of the waterproof and oil-proof paper-based material containing a composite coating provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only applicable to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, the present invention can also be improved and modified without departing from the principle of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a waterproof and oil-proof paper-based material containing a composite coating, characterized in that: The steps include: S1, preparing a sodium alginate aqueous solution to obtain coating A; S2, preparing a mixed solution of PLA and PBAT to obtain coating B; S3, coating the coating A evenly on the surface of the kraft paper, and then drying and hot pressing to obtain a dry kraft paper with a smooth surface; S4. Coating B evenly on the surface of kraft paper coated with coating A, and fully drying, thereby obtaining a waterproof and oil-proof paper-based material containing a composite coating of sodium alginate, PLA and PBAT.

2. The method for preparing a waterproof and oil-proof paper-based material containing a composite coating according to claim 1, characterized in that: In step S1, the mass volume percentage concentration of the sodium alginate aqueous solution is 1% to 4%.

3. The method for preparing a waterproof and oil-proof paper-based material containing a composite coating according to claim 2, characterized in that: The sodium alginate aqueous solution is prepared by pouring weighed deionized water into a beaker, placing the beaker in a 45° C. water bath, pouring a certain amount of sodium alginate under magnetic stirring, stirring for 1 hour, and obtaining a sodium alginate solution with a mass volume percentage concentration of 1% to 4%.

4. The method for preparing a waterproof and oil-proof paper-based material containing a composite coating according to claim 1, characterized in that: In step S2, the mass volume percentage concentration of the PLA and PBAT mixed solution is 5% to 15%.

5. The method for preparing a waterproof and oil-proof paper-based material containing a composite coating according to claim 4, characterized in that: The preparation method of the PLA and PBAT mixed solution is as follows: PLA and PBAT particles are weighed in a certain proportion, poured into a reagent bottle, a solvent is added, and the mixture is shaken in a 45° C. water bath for 4 hours to fully dissolve the particles, and allowed to stand to eliminate bubbles, thereby obtaining a PLA and PBAT mixed solution having a mass volume percentage concentration of 5% to 15%.

6. The method for preparing a waterproof and oil-proof paper-based material containing a composite coating according to claim 5, characterized in that: The mass ratio of PLA and PBAT weighed is 5:1-10.

7. The method for preparing a waterproof and oil-proof paper-based material containing a composite coating according to claim 5, characterized in that: The solvent is one of dichloromethane and chloroform.

8. The method for preparing a waterproof and oil-proof paper-based material containing a composite coating according to claim 1, characterized in that: In step S3, the kraft paper coated with coating A is dried in an oven at 105°C for 2 minutes, and then hot-pressed at a temperature of 105°C and a pressure of about 0.2 kPa for 1 minute to obtain a dry kraft paper with a smooth surface.

9. The method for preparing a waterproof and oil-proof paper-based material containing a composite coating according to claim 1, characterized in that: In step S3, the coating amount of coating A is controlled to be 1-4 g / m 2 In step S4, the coating amount of coating B is controlled to 3-10g / m 2 ; The total coating amount is controlled to 1-13g / m 2 .

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