Waterproof paper pulp molding material and preparation method thereof

Abstract

The invention provides a waterproof paper pulp molding material as well as a preparation method and application thereof, and the waterproof paper pulp molding material comprises bamboo-wood mixed pulp, hydrophobic modified chitosan, hydrophobic modified cyclodextrin, a sizing agent and a retention aid. Hydrophobic modified chitosan and hydrophobic modified cyclodextrin are added into the paper pulp molding material, hydroxyl and amino on the surface of chitosan are subjected to hydrophobic modification through short-carbon-chain heptafluorobutyric acid and AKD, and hydroxyl on the surface of cyclodextrin is subjected to hydrophobic modification through AKD; hydrophilic groups on the surfaces of chitosan and cyclodextrin are modified, and meanwhile, the synergistic effect of chitosan and cyclodextrin is utilized, so that the finally obtained paper pulp molding material has good waterproof performance, Cobb60 is smaller than 8 g / m < 2 >, the static water contact angle is larger than 125 degrees, and after standing in hot water for 30 min, the back face of a sample is free of negative permeation, leakage and deformation; the application of the paper pulp molding material in the field of waterproof packaging is greatly expanded.

Description

Technical Field

[0001] The invention relates to the field of pulp molding materials, in particular to a waterproof pulp molding material and a preparation method thereof. Background Art

[0002] Pulp molding material, as a new type of environmentally friendly packaging material, has received widespread attention and application around the world in recent years. It is a three-dimensional paper product made by pulping, molding, drying and other processes of waste paper and plant fibers (such as sugarcane bagasse, bamboo fiber, wheat straw, rice straw, reed and other renewable resources).

[0003] According to different raw materials, existing pulp molding materials are mainly divided into the following categories:

[0004] Waste paper pulp molding material: Made from recycled waste paper as raw material after processing. This type of material is low-cost, helps to recycle resources, and reduces environmental pollution caused by landfill and incineration.

[0005] Plant fiber molding materials: using sugarcane bagasse, bamboo fiber, wheat straw and other plant fibers as raw materials, these materials not only have excellent physical properties, such as high strength and good toughness, but also fully meet environmental protection requirements and can be naturally degraded.

[0006] Composite pulp molding material: It combines the advantages of waste paper pulp and plant fiber and is processed through a special process to improve the comprehensive performance of the material, such as enhancing waterproofness and oil resistance.

[0007] Pulp molding materials, with their unique environmental friendliness, biodegradability, cushioning and good air permeability, show great application potential in packaging, tableware, agriculture, construction and other fields.

[0008] Although pulp molding materials have many advantages, in practical applications, since pulp molding materials are mainly composed of plant fibers, their natural hydrophilicity leads to poor waterproof performance, which limits their application in certain fields that require waterproofing and moisture-proofing.

[0009] Therefore, in view of the problems existing in the prior art, developing a pulp molding material with excellent waterproof performance has practical significance and economic value, which can further promote the sustainable and healthy development of the pulp molding material industry. Summary of the invention

[0010] In view of the defects of the above-mentioned prior art, an object of the present invention is to provide a pulp molding material with excellent waterproof performance and a preparation method thereof, aiming to solve the technical problem that the existing pulp molding material has poor waterproof performance.

[0011] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0012] A waterproof pulp molding material, comprising the following components and their mass fractions:

[0013] 60-80 parts of bamboo-wood mixed pulp

[0014] 10-15 parts of hydrophobic modified chitosan

[0015] 3-10 parts of hydrophobic modified cyclodextrin

[0016] Sizing agent 1-3 parts

[0017] Retention aid 0.1-0.5 parts.

[0018] The bamboo-wood mixed pulp is obtained by mixing 70 wt% of bamboo chemical pulp and 30 wt% of coniferous wood chemical pulp;

[0019] The mass ratio of the hydrophobically modified chitosan to the hydrophobically modified cyclodextrin is (2-5):1;

[0020] The hydrophobic modified chitosan is chitosan modified by heptafluorobutyric acid and alkyl ketene dimer AKD, and its specific preparation method is as follows:

[0021] (1) dissolving an appropriate amount of chitosan and heptafluorobutyric acid in an organic solvent, dimethyl sulfoxide, with a solid content of 20 wt%, adding a dehydrating agent, EDC·HCl, reacting at 40-60° C. in the dark for 15-30 h, centrifugally filtering, washing with alcohol, and drying to obtain heptafluorobutyric acid-modified chitosan;

[0022] (2) Dissolving chitosan modified with heptafluorobutyric acid and alkyl ketene dimer AKD in ethyl acetate with a solid content of 20 wt %, reacting at 60-80° C. for 5-8 h, centrifuging, washing with alcohol, and drying to obtain hydrophobic modified chitosan.

[0023] The molar ratio of heptafluorobutyric acid, alkyl ketene dimer AKD and chitosan is (3-5): (5-7): 1; the molar ratio of heptafluorobutyric acid and dehydrating agent EDC·HCl is 1:3.

[0024] The hydrophobic modified cyclodextrin is cyclodextrin modified with alkyl ketene dimer AKD, and its specific preparation method is as follows:

[0025] Cyclodextrin and alkyl ketene dimer AKD are dissolved in ethyl acetate with a solid content of 20 wt%, reacted at 60-80° C. for 5-8 hours, centrifuged, washed with alcohol, and dried to obtain hydrophobically modified cyclodextrin.

[0026] Wherein, the molar ratio of alkyl ketene dimer AKD and cyclodextrin is (8-10):1.

[0027] The sizing agent is selected from a mixture of one or more of anionic dispersed rosin glue, cationic dispersed rosin glue, and alkyl ketene dimer AKD;

[0028] The retention aid is selected from a mixture of one or more of cationic polyacrylamide, anionic polyacrylamide, amphoteric polyacrylamide and polyethyleneimine.

[0029] A second object of the present invention is to provide a method for preparing a waterproof pulp molding material, comprising the following steps:

[0030] S1. Weigh the raw materials according to mass: bamboo-wood mixed pulp, hydrophobically modified chitosan, hydrophobically modified cyclodextrin, sizing agent and retention agent;

[0031] S2, dispersing the bamboo-wood mixed pulp in the pulping machine pulp tank for a period of time, adding tap water to dilute to a certain pulp concentration, and then sequentially adding the hydrophobically modified chitosan, hydrophobically modified cyclodextrin, sizing agent and retention agent in the form of in-slurry sizing to obtain a mixed slurry, wherein each component is mixed for 15-30 minutes after being added, and then the next component is added;

[0032] S3, transferring the mixed slurry to a mold for molding, pressurizing at 1000 kPa for 5-10 min, and drying at 100-120° C. for 30 min to obtain a semi-finished pulp molding material;

[0033] S4: vacuum dehydrating the obtained semi-finished pulp molding material for 5-8 minutes to obtain a pulp molding material.

[0034] Preferably, the decomposition time in step S2 is 5-20 min, and the pulp concentration after dilution is 5wt%%-10wt%%.

[0035] The third object of the present invention is to provide a waterproof pulp molding material for use in the field of waterproof packaging.

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] (1) The present invention creatively adds hydrophobically modified chitosan and hydrophobically modified cyclodextrin into the pulp molding material by means of in-slurry sizing. On the one hand, the waterproof properties of the chitosan and cyclodextrin structures are utilized. On the other hand, the hydroxyl groups and amino groups on the surface of chitosan are hydrophobically modified by heptafluorobutyric acid and AKD, and the hydroxyl groups on the surface of cyclodextrin are hydrophobically modified by AKD. The hydrophilic groups on the surfaces of chitosan and cyclodextrin are modified, so that the finally obtained pulp molding material has good waterproof properties, Cobb60 < 8 g / m 2 , static water contact angle>125°, after hot water was left standing for 30 minutes, there was no seepage, leakage or deformation on the back of the sample.

[0038] (2) The present invention creatively discovered that the addition of hydrophobically modified chitosan and hydrophobically modified cyclodextrin to the pulp molding material produces a synergistic effect and jointly improves the waterproof performance of the pulp molding material. DETAILED DESCRIPTION

[0039] The raw materials and equipment used in the present invention, unless otherwise specified, are all commonly used raw materials and equipment in the art; the methods used in the present invention, unless otherwise specified, are all conventional methods in the art.

[0040] Unless otherwise specified, the meanings of the terms in this specification are the same as those generally understood by those skilled in the art. However, if there is any conflict, the definitions in this specification shall prevail.

[0041] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0042] The raw materials are selected as follows:

[0043] Bamboo pulp chemical pulp: Luzhou Yongfeng, bamboo pulp chemical pulp;

[0044] Coniferous wood chemical pulp: Zhejiang Zhongyi Paper Co., Ltd., bleached coniferous pulp;

[0045] Chitosan: Shanghai Aladdin Biochemical Technology Co., Ltd., deacetylation degree ≥ 95%, viscosity 100-200 mPa·s;

[0046] Cyclodextrin: Qianhui Biotechnology, CAS NO.: 7585-39-9;

[0047] Heptafluorobutyric acid: Shanghai McLean, CAS NO.: 375-22-4;

[0048] Sizing agent: Qingzhou Jinhao New Materials Co., Ltd., alkyl ketene dimer AKD;

[0049] Retention aid: cationic polyacrylamide, Xinqi Chemical.

[0050] Preparation of hydrophobic modified chitosan

[0051] Preparation Example 1

[0052] Preparation of hydrophobic modified chitosan SK1:

[0053] (1) dissolving an appropriate amount of chitosan and heptafluorobutyric acid in an organic solvent of dimethyl sulfoxide with a solid content of 20 wt %, adding a dehydrating agent EDC·HCl, reacting at 40° C. in the dark for 20 h, centrifuging, rinsing three times with anhydrous ethanol, and vacuum drying at 85° C. for 3 h to obtain heptafluorobutyric acid-modified chitosan;

[0054] (4) The chitosan modified with heptafluorobutyric acid and alkyl ketene dimer AKD were dissolved in ethyl acetate with a solid content of 20 wt%, reacted at 80°C for 6 h, centrifuged, rinsed three times with anhydrous ethanol, and vacuum dried at 85°C for 3 h to obtain the hydrophobic modified chitosan.

[0055] The molar ratio of heptafluorobutyric acid, alkyl ketene dimer AKD and chitosan is 3:5:1; the molar ratio of heptafluorobutyric acid and dehydrating agent EDC·HCl is 1:3.

[0056] Preparation Example 2

[0057] Preparation of hydrophobic modified chitosan SK2:

[0058] (1) dissolving an appropriate amount of chitosan and heptafluorobutyric acid in an organic solvent of dimethyl sulfoxide with a solid content of 20 wt %, adding a dehydrating agent EDC·HCl, reacting at 40° C. in the dark for 20 h, centrifuging, rinsing three times with anhydrous ethanol, and vacuum drying at 85° C. for 3 h to obtain heptafluorobutyric acid-modified chitosan;

[0059] (4) The chitosan modified with heptafluorobutyric acid and alkyl ketene dimer AKD were dissolved in ethyl acetate with a solid content of 20 wt %, reacted at 80° C. for 6 h, centrifuged, rinsed three times with anhydrous ethanol, and vacuum dried at 85° C. for 3 h to obtain the hydrophobic modified chitosan.

[0060] The molar ratio of heptafluorobutyric acid, alkyl ketene dimer AKD and chitosan is 3:7:1; the molar ratio of heptafluorobutyric acid and dehydrating agent EDC·HCl is 1:3.

[0061] Preparation Example 3

[0062] Preparation of hydrophobic modified chitosan SK3:

[0063] (1) dissolving an appropriate amount of chitosan and heptafluorobutyric acid in an organic solvent of dimethyl sulfoxide with a solid content of 20 wt %, adding a dehydrating agent EDC·HCl, reacting at 40° C. in the dark for 20 h, centrifuging, rinsing three times with anhydrous ethanol, and vacuum drying at 85° C. for 3 h to obtain heptafluorobutyric acid-modified chitosan;

[0064] (4) The chitosan modified with heptafluorobutyric acid and alkyl ketene dimer AKD were dissolved in ethyl acetate with a solid content of 20 wt %, reacted at 80° C. for 6 h, centrifuged, rinsed three times with anhydrous ethanol, and vacuum dried at 85° C. for 3 h to obtain the hydrophobic modified chitosan.

[0065] The molar ratio of heptafluorobutyric acid, alkyl ketene dimer AKD and chitosan is 5:5:1; the molar ratio of heptafluorobutyric acid and dehydrating agent EDC·HCl is 1:3.

[0066] Preparation Example 4

[0067] Preparation of hydrophobic modified chitosan SK4:

[0068] (1) dissolving an appropriate amount of chitosan and heptafluorobutyric acid in an organic solvent, dimethyl sulfoxide, with a solid content of 20 wt%, adding a dehydrating agent, EDC·HCl, reacting at 40° C. in the dark for 20 h, centrifuging, rinsing three times with anhydrous ethanol, and vacuum drying at 85° C. for 3 h to obtain heptafluorobutyric acid-modified chitosan;

[0069] (4) The chitosan modified with heptafluorobutyric acid and alkyl ketene dimer AKD were dissolved in ethyl acetate with a solid content of 20 wt%, reacted at 80°C for 6 h, centrifuged, rinsed three times with anhydrous ethanol, and vacuum dried at 85°C for 3 h to obtain the hydrophobic modified chitosan.

[0070] The molar ratio of heptafluorobutyric acid, alkyl ketene dimer AKD and chitosan is 5:7:1; the molar ratio of heptafluorobutyric acid and dehydrating agent EDC·HCl is 1:3.

[0071] Comparative Preparation Example 1

[0072] Preparation of hydrophobic modified chitosan SK-C1:

[0073] (1) dissolving an appropriate amount of chitosan and heptafluorobutyric acid in an organic solvent of dimethyl sulfoxide with a solid content of 20 wt %, adding a dehydrating agent EDC·HCl, reacting at 40° C. in the dark for 20 h, centrifuging, rinsing three times with anhydrous ethanol, and vacuum drying at 85° C. for 3 h to obtain heptafluorobutyric acid-modified chitosan;

[0074] (4) The chitosan modified with heptafluorobutyric acid and alkyl ketene dimer AKD were dissolved in ethyl acetate with a solid content of 20 wt%, reacted at 80°C for 6 h, centrifuged, rinsed three times with anhydrous ethanol, and vacuum dried at 85°C for 3 h to obtain the hydrophobic modified chitosan.

[0075] The molar ratio of heptafluorobutyric acid, alkyl ketene dimer AKD and chitosan is 2:5:1; the molar ratio of heptafluorobutyric acid and dehydrating agent EDC·HCl is 1:3.

[0076] Comparative Preparation Example 2

[0077] Preparation of hydrophobic modified chitosan SK-C2:

[0078] (1) dissolving an appropriate amount of chitosan and heptafluorobutyric acid in an organic solvent of dimethyl sulfoxide with a solid content of 20 wt %, adding a dehydrating agent EDC·HCl, reacting at 40° C. in the dark for 20 h, centrifuging, rinsing three times with anhydrous ethanol, and vacuum drying at 85° C. for 3 h to obtain heptafluorobutyric acid-modified chitosan;

[0079] (4) The chitosan modified with heptafluorobutyric acid and alkyl ketene dimer AKD were dissolved in ethyl acetate with a solid content of 20 wt%, reacted at 80°C for 6 h, centrifuged, rinsed three times with anhydrous ethanol, and vacuum dried at 85°C for 3 h to obtain the hydrophobic modified chitosan.

[0080] The molar ratio of heptafluorobutyric acid, alkyl ketene dimer AKD and chitosan is 5:8:1; the molar ratio of heptafluorobutyric acid and dehydrating agent EDC·HCl is 1:3.

[0081] Comparative Preparation Example 3

[0082] Preparation of chitosan SK-C3 treated with heptafluorobutyric acid:

[0083] An appropriate amount of chitosan and heptafluorobutyric acid were dissolved in an organic solvent, dimethyl sulfoxide, with a solid content of 20 wt%. Dehydrating agent EDC·HCl was added, and the mixture was reacted at 40°C in the dark for 20 h. After centrifugal filtration, the mixture was washed three times with anhydrous ethanol, and vacuum dried at 85°C for 3 h, heptafluorobutyric acid-modified chitosan was obtained.

[0084] The molar ratio of heptafluorobutyric acid to chitosan is 10:1; and the molar ratio of heptafluorobutyric acid to dehydrating agent EDC·HCl is 1:3.

[0085] Comparative Preparation Example 4

[0086] Preparation of chitosan SK-C4 modified with alkyl ketene dimer AKD:

[0087] Appropriate amounts of chitosan and alkyl ketene dimer AKD were dissolved in ethyl acetate with a solid content of 20 wt%, reacted at 80°C for 6 h, centrifuged, rinsed three times with anhydrous ethanol, and vacuum dried at 85°C for 3 h to obtain chitosan modified with alkyl ketene dimer AKD.

[0088] The molar ratio of alkyl ketene dimer AKD and chitosan is 10:1.

[0089] Preparation of hydrophobic modified cyclodextrin

[0090] Preparation Example 1

[0091] Preparation of hydrophobically modified cyclodextrin SH1:

[0092] Cyclodextrin and alkyl ketene dimer AKD were dissolved in ethyl acetate with a solid content of 20 wt %, reacted at 80° C. for 8 h, centrifuged, washed with anhydrous ethanol for 3 times, and vacuum dried at 85° C. for 3 h to obtain hydrophobically modified cyclodextrin.

[0093] The molar ratio of alkyl ketene dimer AKD and cyclodextrin is 8:1.

[0094] Preparation Example 2'

[0095] Preparation of hydrophobically modified cyclodextrin SH2:

[0096] Cyclodextrin and alkyl ketene dimer AKD were dissolved in ethyl acetate with a solid content of 20 wt%, reacted at 80°C for 8 h, centrifuged, washed with anhydrous ethanol for 3 times, and vacuum dried at 85°C for 3 h to obtain hydrophobically modified cyclodextrin.

[0097] The molar ratio of alkyl ketene dimer AKD to cyclodextrin is 10:1.

[0098] Comparative Preparation Example 1'

[0099] Preparation of hydrophobic modified cyclodextrin SH-C1:

[0100] Cyclodextrin and alkyl ketene dimer AKD were dissolved in ethyl acetate with a solid content of 20 wt%, reacted at 80°C for 8 h, centrifuged, washed with anhydrous ethanol for 3 times, and vacuum dried at 85°C for 3 h to obtain hydrophobically modified cyclodextrin.

[0101] The molar ratio of alkyl ketene dimer AKD and cyclodextrin is 6:1.

[0102] Example 1

[0103] A preparation method of a waterproof pulp molding material comprises the following steps:

[0104] S1. Weigh the raw materials according to the following components and their mass fractions:

[0105] Bamboo-wood mixed pulp (mixture of 70wt% bamboo chemical pulp and 30wt% coniferous wood chemical pulp) 80 parts

[0106] Hydrophobic modified chitosan SK110 parts

[0107] Hydrophobic modified cyclodextrin SH 15 parts

[0108] Alkyl ketene dimer AKD 3 parts

[0109] 0.5 parts of cationic polyacrylamide;

[0110] S2, dispersing the bamboo-wood mixed pulp in the pulping machine pulp tank for 20 minutes, adding tap water to dilute the pulp to a pulp concentration of 5wt%, and then adding the hydrophobically modified chitosan SK1, the hydrophobically modified cyclodextrin SH1, the sizing agent and the retention agent in sequence by the method of in-slurry sizing to obtain a mixed slurry, wherein each component is mixed for 30 minutes after being added, and then the next component is added;

[0111] S3, transferring the mixed slurry to a mold for molding, pressurizing at 1000 kPa for 5 min, and drying at 120° C. for 30 min to obtain a semi-finished pulp molding material;

[0112] S4: vacuum dehydrating the obtained semi-finished pulp molding material for 5 minutes to obtain a pulp molding material.

[0113] Example 2

[0114] A preparation method of a waterproof pulp molding material comprises the following steps:

[0115] S1. Weigh the raw materials according to the following components and their mass fractions:

[0116] Bamboo-wood mixed pulp (mixture of 70wt% bamboo chemical pulp and 30wt% coniferous wood chemical pulp) 80 parts

[0117] Hydrophobic modified chitosan SK2 10 parts

[0118] Hydrophobic modified cyclodextrin SH 15 parts

[0119] Alkyl ketene dimer AKD 3 parts

[0120] 0.5 parts of cationic polyacrylamide;

[0121] S2, dispersing the bamboo-wood mixed pulp in the pulping machine pulp tank for 20 minutes, adding tap water to dilute the pulp to a pulp concentration of 5wt%, and then adding the hydrophobically modified chitosan SK2, the hydrophobically modified cyclodextrin SH1, the sizing agent and the retention agent in sequence by the method of in-slurry sizing to obtain a mixed slurry, wherein each component is mixed for 30 minutes after being added, and then the next component is added;

[0122] S3, transferring the mixed slurry to a mold for molding, pressurizing at 1000 kPa for 5 min, and drying at 120° C. for 30 min to obtain a semi-finished pulp molding material;

[0123] S4: vacuum dehydrating the obtained semi-finished pulp molding material for 5 minutes to obtain a pulp molding material.

[0124] Example 3

[0125] A preparation method of a waterproof pulp molding material comprises the following steps:

[0126] S1. Weigh the raw materials according to the following components and their mass fractions:

[0127] Bamboo-wood mixed pulp (mixture of 70wt% bamboo chemical pulp and 30wt% coniferous wood chemical pulp) 80 parts

[0128] Hydrophobic modified chitosan SK3 10 parts

[0129] Hydrophobic modified cyclodextrin SH 15 parts

[0130] Alkyl ketene dimer AKD 3 parts

[0131] 0.5 parts of cationic polyacrylamide;

[0132] S2, dispersing the bamboo-wood mixed pulp in the pulping machine pulp tank for 20 minutes, adding tap water to dilute the pulp to a pulp concentration of 5wt%, and then adding the hydrophobically modified chitosan SK3, the hydrophobically modified cyclodextrin SH1, the sizing agent and the retention agent in sequence by the method of in-slurry sizing to obtain a mixed slurry, wherein each component is mixed for 30 minutes after being added, and then the next component is added;

[0133] S3, transferring the mixed slurry to a mold for molding, pressurizing at 1000 kPa for 5 min, and drying at 120° C. for 30 min to obtain a semi-finished pulp molding material;

[0134] S4: vacuum dehydrating the obtained semi-finished pulp molding material for 5 minutes to obtain a pulp molding material.

[0135] Example 4

[0136] A preparation method of a waterproof pulp molding material comprises the following steps:

[0137] S1. Weigh the raw materials according to the following components and their mass fractions:

[0138] Bamboo-wood mixed pulp (mixture of 70wt% bamboo chemical pulp and 30wt% coniferous wood chemical pulp) 80 parts

[0139] Hydrophobic modified chitosan SK4 10 parts

[0140] Hydrophobic modified cyclodextrin SH 15 parts

[0141] Alkyl ketene dimer AKD 3 parts

[0142] 0.5 parts of cationic polyacrylamide;

[0143] S2, dispersing the bamboo-wood mixed pulp in the pulping machine pulp tank for 20 minutes, adding tap water to dilute the pulp to a pulp concentration of 5wt%, and then adding the hydrophobically modified chitosan SK4, the hydrophobically modified cyclodextrin SH1, the sizing agent and the retention agent in sequence by the method of in-slurry sizing to obtain a mixed slurry, wherein each component is mixed for 30 minutes after being added, and then the next component is added;

[0144] S3, transferring the mixed slurry to a mold for molding, pressurizing at 1000 kPa for 5 min, and drying at 120° C. for 30 min to obtain a semi-finished pulp molding material;

[0145] S4: vacuum dehydrating the obtained semi-finished pulp molding material for 5 minutes to obtain a pulp molding material.

[0146] Example 5

[0147] A preparation method of a waterproof pulp molding material comprises the following steps:

[0148] S1. Weigh the raw materials according to the following components and their mass fractions:

[0149] Bamboo-wood mixed pulp (mixture of 70wt% bamboo chemical pulp and 30wt% coniferous wood chemical pulp) 80 parts

[0150] Hydrophobic modified chitosan SK2 10 parts

[0151] Hydrophobic modified cyclodextrin SH25 parts

[0152] Alkyl ketene dimer AKD 3 parts

[0153] 0.5 parts of cationic polyacrylamide;

[0154] S2, dispersing the bamboo-wood mixed pulp in the pulping tank of the pulper for 20 minutes, adding tap water to dilute the pulp to a pulp concentration of 5wt%, and then sequentially adding the hydrophobically modified chitosan SK2, the hydrophobically modified cyclodextrin SH2, the sizing agent and the retention agent by means of in-slurry sizing to obtain a mixed slurry, wherein each component is mixed for 30 minutes after being added, and then the next component is added;

[0155] S3, transferring the mixed slurry to a mold for molding, pressurizing at 1000 kPa for 5 min, and drying at 120° C. for 30 min to obtain a semi-finished pulp molding material;

[0156] S4: vacuum dehydrating the obtained semi-finished pulp molding material for 5 minutes to obtain a pulp molding material.

[0157] Example 6

[0158] A preparation method of a waterproof pulp molding material comprises the following steps:

[0159] S1. Weigh the raw materials according to the following components and their mass fractions:

[0160] Bamboo-wood mixed pulp (mixture of 70wt% bamboo chemical pulp and 30wt% coniferous wood chemical pulp) 80 parts

[0161] Hydrophobic modified chitosan SK215 parts

[0162] Hydrophobic modified cyclodextrin SH 15 parts

[0163] Alkyl ketene dimer AKD 3 parts

[0164] 0.5 parts of cationic polyacrylamide;

[0165] S2, dispersing the bamboo-wood mixed pulp in the pulping machine pulp tank for 20 minutes, adding tap water to dilute the pulp to a pulp concentration of 5wt%, and then adding the hydrophobically modified chitosan SK2, the hydrophobically modified cyclodextrin SH1, the sizing agent and the retention agent in sequence by the method of in-slurry sizing to obtain a mixed slurry, wherein each component is mixed for 30 minutes after being added, and then the next component is added;

[0166] S3, transferring the mixed slurry to a mold for molding, pressurizing at 1000 kPa for 5 min, and drying at 120° C. for 30 min to obtain a semi-finished pulp molding material;

[0167] S4: vacuum dehydrating the obtained semi-finished pulp molding material for 5 minutes to obtain a pulp molding material.

[0168] Example 7

[0169] A preparation method of a waterproof pulp molding material comprises the following steps:

[0170] S1. Weigh the raw materials according to the following components and their mass fractions:

[0171] Bamboo-wood mixed pulp (mixture of 70wt% bamboo chemical pulp and 30wt% coniferous wood chemical pulp) 80 parts

[0172] Hydrophobic modified chitosan SK215 parts

[0173] Hydrophobic modified cyclodextrin SH 13 parts

[0174] Alkyl ketene dimer AKD 3 parts

[0175] 0.5 parts of cationic polyacrylamide;

[0176] S2, dispersing the bamboo-wood mixed pulp in the pulping machine pulp tank for 20 minutes, adding tap water to dilute the pulp to a pulp concentration of 5wt%, and then adding the hydrophobically modified chitosan SK2, the hydrophobically modified cyclodextrin SH1, the sizing agent and the retention agent in sequence by the method of in-slurry sizing to obtain a mixed slurry, wherein each component is mixed for 30 minutes after being added, and then the next component is added;

[0177] S3, transferring the mixed slurry to a mold for molding, pressurizing at 1000 kPa for 5 min, and drying at 120° C. for 30 min to obtain a semi-finished pulp molding material;

[0178] S4: vacuum dehydrating the obtained semi-finished pulp molding material for 5 minutes to obtain a pulp molding material.

[0179] Comparative Example 1

[0180] A preparation method of a waterproof pulp molding material comprises the following steps:

[0181] S1. Weigh the raw materials according to the following components and their mass fractions:

[0182] Bamboo-wood mixed pulp (mixture of 70wt% bamboo chemical pulp and 30wt% coniferous wood chemical pulp) 80 parts

[0183] Hydrophobic modified chitosan SK2 10 parts

[0184] Hydrophobic modified cyclodextrin SH110 parts

[0185] Alkyl ketene dimer AKD 3 parts

[0186] 0.5 parts of cationic polyacrylamide;

[0187] S2, dispersing the bamboo-wood mixed pulp in the pulping machine pulp tank for 20 minutes, adding tap water to dilute the pulp to a pulp concentration of 5wt%, and then adding the hydrophobically modified chitosan SK2, the hydrophobically modified cyclodextrin SH1, the sizing agent and the retention agent in sequence by the method of in-slurry sizing to obtain a mixed slurry, wherein each component is mixed for 30 minutes after being added, and then the next component is added;

[0188] S3, transferring the mixed slurry to a mold for molding, pressurizing at 1000 kPa for 5 min, and drying at 120° C. for 30 min to obtain a semi-finished pulp molding material;

[0189] S4: vacuum dehydrating the obtained semi-finished pulp molding material for 5 minutes to obtain a pulp molding material.

[0190] Comparative Example 2

[0191] A preparation method of a waterproof pulp molding material comprises the following steps:

[0192] S1. Weigh the raw materials according to the following components and their mass fractions:

[0193] Bamboo-wood mixed pulp (mixture of 70wt% bamboo chemical pulp and 30wt% coniferous wood chemical pulp) 80 parts

[0194] Hydrophobic modified chitosan SK215 parts

[0195] Hydrophobic modified cyclodextrin SH 12.5 parts

[0196] Alkyl ketene dimer AKD 3 parts

[0197] 0.5 parts of cationic polyacrylamide;

[0198] S2, dispersing the bamboo-wood mixed pulp in the pulping machine pulp tank for 20 minutes, adding tap water to dilute the pulp to a pulp concentration of 5wt%, and then adding the hydrophobically modified chitosan SK2, the hydrophobically modified cyclodextrin SH1, the sizing agent and the retention agent in sequence by the method of in-slurry sizing to obtain a mixed slurry, wherein each component is mixed for 30 minutes after being added, and then the next component is added;

[0199] S3, transferring the mixed slurry to a mold for molding, pressurizing at 1000 kPa for 5 min, and drying at 120° C. for 30 min to obtain a semi-finished pulp molding material;

[0200] S4: vacuum dehydrating the obtained semi-finished pulp molding material for 5 minutes to obtain a pulp molding material.

[0201] Comparative Example 3

[0202] A preparation method of a waterproof pulp molding material comprises the following steps:

[0203] S1. Weigh the raw materials according to the following components and their mass fractions:

[0204] Bamboo-wood mixed pulp (mixture of 70wt% bamboo chemical pulp and 30wt% coniferous wood chemical pulp) 80 parts

[0205] Hydrophobic modified chitosan SK-C 110 parts

[0206] Hydrophobic modified cyclodextrin SH 15 parts

[0207] Alkyl ketene dimer AKD 3 parts

[0208] 0.5 parts of cationic polyacrylamide;

[0209] S2, dispersing the bamboo-wood mixed pulp in the pulping tank of the pulper for 20 minutes, adding tap water to dilute the pulp to a pulp concentration of 5wt%, and then sequentially adding hydrophobically modified chitosan SK-C1, hydrophobically modified cyclodextrin SH1, sizing agent and retention agent by sizing in the pulp to obtain a mixed pulp, wherein each component is mixed for 30 minutes after being added, and then the next component is added;

[0210] S3, transferring the mixed slurry to a mold for molding, pressurizing at 1000 kPa for 5 min, and drying at 120° C. for 30 min to obtain a semi-finished pulp molding material;

[0211] S4: vacuum dehydrating the obtained semi-finished pulp molding material for 5 minutes to obtain a pulp molding material.

[0212] Comparative Example 4

[0213] A preparation method of a waterproof pulp molding material comprises the following steps:

[0214] S1. Weigh the raw materials according to the following components and their mass fractions:

[0215] Bamboo-wood mixed pulp (mixture of 70wt% bamboo chemical pulp and 30wt% coniferous wood chemical pulp) 80 parts

[0216] Hydrophobic modified chitosan SK-C2 10 parts

[0217] Hydrophobic modified cyclodextrin SH 15 parts

[0218] Alkyl ketene dimer AKD 3 parts

[0219] 0.5 parts of cationic polyacrylamide;

[0220] S2, dispersing the bamboo-wood mixed pulp in the pulping machine trough for 20 minutes, adding tap water to dilute the pulp to a pulp concentration of 5wt%, and then adding the hydrophobically modified chitosan SK-C2, the hydrophobically modified cyclodextrin SH1, the sizing agent and the retention agent in sequence by the method of in-slurry sizing to obtain a mixed slurry, wherein each component is mixed for 30 minutes after being added, and then the next component is added;

[0221] S3, transferring the mixed slurry to a mold for molding, pressurizing at 1000 kPa for 5 min, and drying at 120° C. for 30 min to obtain a semi-finished pulp molding material;

[0222] S4: vacuum dehydrating the obtained semi-finished pulp molding material for 5 minutes to obtain a pulp molding material.

[0223] Comparative Example 5

[0224] A preparation method of a waterproof pulp molding material comprises the following steps:

[0225] S1. Weigh the raw materials according to the following components and their mass fractions:

[0226] Bamboo-wood mixed pulp (mixture of 70wt% bamboo chemical pulp and 30wt% coniferous wood chemical pulp) 80 parts

[0227] Hydrophobic modified chitosan SK-C3 10 parts

[0228] Hydrophobic modified cyclodextrin SH 15 parts

[0229] Alkyl ketene dimer AKD 3 parts

[0230] 0.5 parts of cationic polyacrylamide;

[0231] S2, dispersing the bamboo-wood mixed pulp in the pulping machine pulp tank for 20 minutes, adding tap water to dilute the pulp to a pulp concentration of 5wt%, and then adding hydrophobically modified chitosan SK-C3, hydrophobically modified cyclodextrin SH1, sizing agent and retention agent in sequence by sizing in the pulp to obtain a mixed pulp, wherein each component is mixed for 30 minutes after being added, and then the next component is added;

[0232] S3, transferring the mixed slurry to a mold for molding, pressurizing at 1000 kPa for 5 min, and drying at 120° C. for 30 min to obtain a semi-finished pulp molding material;

[0233] S4: vacuum dehydrating the obtained semi-finished pulp molding material for 5 minutes to obtain a pulp molding material.

[0234] Comparative Example 6

[0235] A preparation method of a waterproof pulp molding material comprises the following steps:

[0236] S1. Weigh the raw materials according to the following components and their mass fractions:

[0237] Bamboo-wood mixed pulp (mixture of 70wt% bamboo chemical pulp and 30wt% coniferous wood chemical pulp) 80 parts

[0238] 10 parts of hydrophobic modified chitosan SK-C4

[0239] Hydrophobic modified cyclodextrin SH 15 parts

[0240] Alkyl ketene dimer AKD 3 parts

[0241] 0.5 parts of cationic polyacrylamide;

[0242] S2, dispersing the bamboo-wood mixed pulp in the pulping tank of the pulper for 20 minutes, adding tap water to dilute the pulp to a pulp concentration of 5wt%, and then sequentially adding hydrophobically modified chitosan SK-C4, hydrophobically modified cyclodextrin SH1, sizing agent and retention agent by sizing in the pulp to obtain a mixed pulp, wherein each component is mixed for 30 minutes after being added, and then the next component is added;

[0243] S3, transferring the mixed slurry to a mold for molding, pressurizing at 1000 kPa for 5 min, and drying at 120° C. for 30 min to obtain a semi-finished pulp molding material;

[0244] S4: vacuum dehydrating the obtained semi-finished pulp molding material for 5 minutes to obtain a pulp molding material.

[0245] Comparative Example 7

[0246] A preparation method of a waterproof pulp molding material comprises the following steps:

[0247] S1. Weigh the raw materials according to the following components and their mass fractions:

[0248] Bamboo-wood mixed pulp (mixture of 70wt% bamboo chemical pulp and 30wt% coniferous wood chemical pulp) 80 parts

[0249] Hydrophobic modified chitosan SK2 10 parts

[0250] Hydrophobic modified cyclodextrin SH-C 15 parts

[0251] Alkyl ketene dimer AKD 3 parts

[0252] 0.5 parts of cationic polyacrylamide;

[0253] S2, dispersing the bamboo-wood mixed pulp in the pulping machine pulp tank for 20 minutes, adding tap water to dilute the pulp to a pulp concentration of 5wt%, and then adding the hydrophobically modified chitosan SK2, hydrophobically modified cyclodextrin SH-C1, sizing agent and retention agent in sequence by in-slurry sizing to obtain a mixed slurry, wherein each component is mixed for 30 minutes after addition, and then the next component is added;

[0254] S3, transferring the mixed slurry to a mold for molding, pressurizing at 1000 kPa for 5 min, and drying at 120° C. for 30 min to obtain a semi-finished pulp molding material;

[0255] S4: vacuum dehydrating the obtained semi-finished pulp molding material for 5 minutes to obtain a pulp molding material.

[0256] Comparative Example 8

[0257] A preparation method of a waterproof pulp molding material comprises the following steps:

[0258] S1. Weigh the raw materials according to the following components and their mass fractions:

[0259] Bamboo-wood mixed pulp (mixture of 70wt% bamboo chemical pulp and 30wt% coniferous wood chemical pulp) 80 parts

[0260] Hydrophobic modified chitosan SK215 parts

[0261] Alkyl ketene dimer AKD 3 parts

[0262] 0.5 parts of cationic polyacrylamide;

[0263] S2, dispersing the bamboo-wood mixed pulp in the pulping tank of the pulper for 20 minutes, adding tap water to dilute the pulp to a pulp concentration of 5wt%, and then adding the hydrophobically modified chitosan SK2, sizing agent and retention agent in sequence by in-slurry sizing to obtain a mixed slurry, wherein each component is mixed for 30 minutes after being added, and then the next component is added;

[0264] S3, transferring the mixed slurry to a mold for molding, pressurizing at 1000 kPa for 5 min, and drying at 120° C. for 30 min to obtain a semi-finished pulp molding material;

[0265] S4: vacuum dehydrating the obtained semi-finished pulp molding material for 5 minutes to obtain a pulp molding material.

[0266] Comparative Example 9

[0267] A preparation method of a waterproof pulp molding material comprises the following steps:

[0268] S1. Weigh the raw materials according to the following components and their mass fractions:

[0269] Bamboo-wood mixed pulp (mixture of 70wt% bamboo chemical pulp and 30wt% coniferous wood chemical pulp) 80 parts

[0270] Hydrophobic modified cyclodextrin SH115 parts

[0271] Alkyl ketene dimer AKD 3 parts

[0272] 0.5 parts of cationic polyacrylamide;

[0273] S2, dispersing the bamboo-wood mixed pulp in the pulping tank of the pulper for 20 minutes, adding tap water to dilute the pulp to a pulp concentration of 5wt%, and then adding the hydrophobically modified cyclodextrin SH1, sizing agent and retention agent in sequence by in-slurry sizing to obtain a mixed pulp, wherein each component is mixed for 30 minutes after being added, and then the next component is added;

[0274] S3, transferring the mixed slurry to a mold for molding, pressurizing at 1000 kPa for 5 min, and drying at 120° C. for 30 min to obtain a semi-finished pulp molding material;

[0275] S4: vacuum dehydrating the obtained semi-finished pulp molding material for 5 minutes to obtain a pulp molding material.

[0276] Comparative Example 10

[0277] A preparation method of a waterproof pulp molding material comprises the following steps:

[0278] S1. Weigh the raw materials according to the following components and their mass fractions:

[0279] Bamboo-wood mixed pulp (mixture of 70wt% bamboo chemical pulp and 30wt% coniferous wood chemical pulp) 80 parts

[0280] Chitosan 10 parts

[0281] Cyclodextrin 5 parts

[0282] Alkyl ketene dimer AKD 3 parts

[0283] 0.5 parts of cationic polyacrylamide;

[0284] S2, dispersing the bamboo-wood mixed pulp in the pulping tank of the pulping machine for 20 minutes, adding tap water to dilute the pulp to a pulp concentration of 5wt%, and then adding chitosan, cyclodextrin, sizing agent and retention agent in sequence by sizing in the pulp to obtain a mixed pulp, wherein each component is mixed for 30 minutes after being added, and then the next component is added;

[0285] S3, transferring the mixed slurry to a mold for molding, pressurizing at 1000 kPa for 5 min, and drying at 120° C. for 30 min to obtain a semi-finished pulp molding material;

[0286] S4: vacuum dehydrating the obtained semi-finished pulp molding material for 5 minutes to obtain a pulp molding material.

[0287] Sample preparation and performance testing:

[0288] The pulp molding materials of the embodiments and comparative examples were placed in a constant temperature and humidity testing machine and treated at a constant temperature and humidity of (23±2)°C and a relative humidity of (50±10)% for 24 hours, and then their waterproof properties were tested.

[0289] The waterproof performance test method is as follows:

[0290] Cobb60 value determination: According to GB / T 1540-2002, the water absorption of pulp molding samples was measured using a Cobb water absorption tester. Cobb60 (g / m2 ) refers to the Cobb value when the water absorption test time is 60s. Five samples are tested for each sample and the average value is taken.

[0291] Static water contact angle test: Cut a 10mm×15mm flat pulp molding sample and fix it on a glass slide with double-sided tape. Use a contact angle tester to measure the wetting properties of deionized water on the surface of the pulp molding sample. Select 5 test points on each sample and take the average value.

[0292] Hot water permeability test: According to GB / T 36787-2018, drop an appropriate amount of (95±5)℃ hot water into the pulp molding sample, let it stand for 30 minutes, and observe whether the hot water leaks.

[0293] The test results are shown in Table 1 below:

[0294] Table 1

[0295]

[0296]

[0297] By comparing Examples 1-7 and Comparative Examples 1-10 in Table 1, it can be seen that the present invention adds hydrophobic modified chitosan and hydrophobic modified cyclodextrin to the pulp molding material by using the method of in-slurry sizing, and hydrophobic modified chitosan by heptafluorobutyric acid and AKD and hydrophobic modified cyclodextrin by AKD, so that the finally obtained pulp molding material has good waterproof performance, Cobb60 < 8g / m 2 , static water contact angle>125°, after hot water was left standing for 30 minutes, there was no seepage, leakage or deformation on the back of the sample.

[0298] From the comparison of Examples 1-7 and Comparative Examples 1-2 in Table 1, it can be seen that when the compounding ratio of the hydrophobically modified chitosan and the hydrophobically modified cyclodextrin in the pulp molding material is not within the range defined by the present invention, various waterproof properties are decreased to a certain extent.

[0299] By comparing Examples 1-7 and Comparative Examples 3-4 and 7 in Table 1, it can be seen that when preparing hydrophobically modified chitosan and hydrophobically modified cyclodextrin, when the molar ratio of heptafluorobutyric acid, AKD and chitosan, or AKD and cyclodextrin is not within the range defined by the present invention, the waterproof properties of the pulp molding material are relatively poor. This may be due to the different degrees of modification of amino groups and hydroxyl groups on the surface of chitosan by heptafluorobutyric acid and AKD, or the effects of AKD on the surface hydroxyl groups of cyclodextrin.

[0300] By comparing Example 7 in Table 1 with Comparative Examples 5-6, it can be seen that when only heptafluorobutyric acid or AKD is used for hydrophobic modification during the preparation of hydrophobic modified chitosan, the waterproof performance of the pulp molding material is poor. This is because there are hydroxyl groups and amino groups on the surface of chitosan. Heptafluorobutyric acid improves the waterproof performance of the fluorine chain segments on the surface after amino group modification. AKD modifies the hydroxyl group and reduces the residual hydrophilic groups on the surface. Modification of the hydroxyl group or the amino group alone cannot achieve a better improvement in the waterproof performance.

[0301] By comparing Examples 1-7 and Comparative Examples 8-10 in Table 1, it can be seen that the addition of hydrophobically modified chitosan and hydrophobically modified cyclodextrin to the pulp molding material produces a synergistic effect and jointly improves the waterproof performance of the pulp molding material, while the addition of chitosan and cyclodextrin without hydrophobic treatment has the worst waterproof performance.

[0302] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention rather than to limit them. Although the embodiments of the present invention have been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the embodiments of the present invention can still be modified or replaced by equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A waterproof pulp molding material, characterized in that: It includes the following components and their mass fractions: 60-80 parts of bamboo-wood mixed pulp 10-15 parts of hydrophobic modified chitosan 3-10 parts of hydrophobic modified cyclodextrin 1-3 parts of sizing agent Retention aid 0.1-0.5 parts; The mass ratio of the hydrophobically modified chitosan to the hydrophobically modified cyclodextrin is (2-5):1; The hydrophobic modified chitosan is chitosan modified by heptafluorobutyric acid and alkyl ketene dimer AKD; wherein the molar ratio of heptafluorobutyric acid, alkyl ketene dimer AKD and chitosan is (3-5): (5-7): 1; The hydrophobic modified cyclodextrin is cyclodextrin modified with alkyl ketene dimer AKD; wherein the molar ratio of alkyl ketene dimer AKD to cyclodextrin is (8-10):

1.

2. The waterproof pulp molding material according to claim 1, characterized in that The bamboo-wood mixed pulp is obtained by mixing 70 wt% bamboo chemical pulp and 30 wt% coniferous wood chemical pulp; The sizing agent is selected from a mixture of one or more of anionic dispersed rosin glue, cationic dispersed rosin glue, and alkyl ketene dimer AKD; The retention aid is selected from a mixture of one or more of cationic polyacrylamide, anionic polyacrylamide, amphoteric polyacrylamide and polyethyleneimine.

3. The waterproof pulp molding material according to claim 1, characterized in that: The specific preparation method of the hydrophobic modified chitosan is as follows: (1) dissolving an appropriate amount of chitosan and heptafluorobutyric acid in an organic solvent, dimethyl sulfoxide, with a solid content of 20 wt%, adding a dehydrating agent, EDC·HCl, reacting at 40-60° C. in the dark for 15-30 h, centrifugally filtering, washing with alcohol, and drying to obtain heptafluorobutyric acid-modified chitosan; (2) Dissolving chitosan modified with heptafluorobutyric acid and alkyl ketene dimer AKD in ethyl acetate with a solid content of 20 wt%, reacting at 60-80°C for 5-8h, centrifuging, washing with alcohol, and drying to obtain hydrophobic modified chitosan; wherein the molar ratio of heptafluorobutyric acid to the dehydrating agent EDC·HCl is 1:

3.

4. The waterproof pulp molding material according to claim 1, characterized in that The specific preparation method of the hydrophobic modified cyclodextrin is as follows: Cyclodextrin and alkyl ketene dimer AKD are dissolved in ethyl acetate with a solid content of 20 wt%, reacted at 60-80° C. for 5-8 hours, centrifuged, washed with alcohol, and dried to obtain hydrophobically modified cyclodextrin.

5. A method for preparing a waterproof pulp molding material according to any one of claims 1 to 4, characterized in that: The steps include: S1. Weigh the raw materials according to mass: bamboo-wood mixed pulp, hydrophobically modified chitosan, hydrophobically modified cyclodextrin, sizing agent and retention aid; S2, dispersing the bamboo-wood mixed pulp in the pulping machine pulp tank for a period of time, adding tap water to dilute to a certain pulp concentration, and then sequentially adding the hydrophobically modified chitosan, hydrophobically modified cyclodextrin, sizing agent and retention agent in the form of in-slurry sizing to obtain a mixed slurry, wherein each component is mixed for 15-30 minutes after being added, and then the next component is added; S3, transferring the mixed slurry to a mold for molding, pressurizing at 1000 kPa for 5-10 min, and drying at 100-120° C. for 30 min to obtain a semi-finished pulp molding material; S4: vacuum dehydrating the obtained semi-finished pulp molding material for 5-8 minutes to obtain a pulp molding material.

6. The method for preparing a waterproof pulp molding material according to claim 5, characterized in that: The decomposition time in step S2 is 5-20 minutes, and the pulp concentration after dilution is 5wt%%-10wt%%.

7. Use of the waterproof pulp molding material according to any one of claims 1 to 4 or the waterproof pulp molding material obtained by the preparation method according to any one of claims 5 to 6 in the field of waterproof packaging.

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