Preparation and use method of fluoride-free waterproof and oil-proof agent for paper pulp molded product

Abstract

The invention relates to a preparation method and a use method of a fluoride-free waterproof and oil-proof agent for a paper pulp molded product, and belongs to the field of waterproof and oil-proof of paper pulp molded products. A traditional pulp molding vacuum suction forming process is adopted, and the fluoride-free waterproof and oil-proof auxiliaries are added in two steps, so that the advantages of the fluoride-free waterproof and oil-proof auxiliaries in a pulp molding structure and on the surface of a finished product are hierarchically and efficiently exerted. The fluoride-free waterproof and oil-proof agent prepared by the invention comprises a component A and a component B. The component A is added into pulp, and a paper pulp molding wet blank 1 is obtained through vacuum suction; carrying out single-side impregnation and suction on the wet blank 1 to obtain a component B, and regulating and controlling the dosage of the component B by controlling time and vacuum degree to obtain a wet blank 2; and hot-pressing and drying the wet blank 2 to obtain an efficient waterproof and oil-proof paper pulp molded product. The fluoride-free waterproof and oil-proof agent disclosed by the invention is finely designed in the structure and on the surface of a paper pulp molded product, is low in cost and environment-friendly, and is particularly suitable for the field of paper pulp molding for food packaging.

Description

Technical Field

[0001] The invention belongs to the field of water and oil proofing of pulp molded food packaging, and specifically relates to a preparation method and a use method of a fluorine-free water and oil proofing agent for pulp molded products for food packaging. Background Art

[0002] The continuous increase in the implementation of the "Plastic Ban / Limit Order" policy has promoted the vigorous development of my country's green environmental protection industry. The development of environmentally friendly biomass materials has become an important direction for the development of the current green packaging industry. Pulp molding products use plant fibers as raw materials, which have the advantages of abundant reserves, recyclability, complete natural degradation, and low cost. After pulping, beating / grinding, and slurry adjustment, the plant fiber raw materials are vacuum-formed on the pulp molding machine, and then hot-pressed, dried, shaped, trimmed, and other processes to obtain the final packaging products with specific geometric cavities. As a truly green packaging material, it is the most ideal choice to replace petroleum-based packaging materials.

[0003] However, traditional pulp molded products have the disadvantage of poor water and oil resistance, which makes them unable to completely replace plastic food packaging. This is mainly related to the fiber itself and its internal structure after molding. Natural plant fibers are formed into a three-dimensional fiber network structure through the pulp molding process, and there are many gaps between fibers. At the same time, there are a large number of hydroxyl groups on cellulose, which leads to poor barrier properties of pulp molded products against air, water and grease.

[0004] There are two common solutions: one is to add waterproof and oil-proof agents to the pulp during the production of pulp molded products; the other is to treat the surface of pulp molding by spraying waterproof and oil-proof agents on the surface. Traditionally, fluorine-containing oil-proof agents are added to the pulp. In recent years, fluorine-containing waterproof and oil-proof agents have gradually withdrawn from the market, and only fluorine-free additives can be added to the pulp. This method has a large demand for fluorine-free additives, high costs and poor effects; and the surface treatment method requires additional spraying equipment, and there are problems such as poor uniformity of surface additive distribution, difficulty in recovering residual additives from spraying, and low surface treatment efficiency. Therefore, the development of new fluorine-free waterproof and oil-proof agents suitable for pulp molding processes has become a hot issue that needs to be urgently solved in the industry. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a preparation and use method of a green and environmentally friendly fluorine-free water and oil repellent for pulp molded products.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A fluorine-free water and oil resistant agent for pulp molded products comprises the following components in mass fractions: 50-90 parts of deionized water, 0.5-5 parts of dispersant, 1-5 parts of butyl acrylate, 2-10 parts of sheet functional material and 0.1-1 part of modified MFC.

[0008] The above dispersant is any one of CMC, cationic starch, PVA and sodium alginate.

[0009] The above-mentioned sheet-like functional material is one or more of talcum powder, kaolin, mica powder and magnesium oxide.

[0010] The modified MFC is one of the microfibrils modified by alkyl ketene dimer, silane series or polyamide polyamine-epichlorohydrin resin.

[0011] The aspect ratio of the modified microfibrils is 50-200.

[0012] The preparation and use method of the above-mentioned fluorine-free water and oil repellent for pulp molded products comprises the following steps:

[0013] a1. The flaky functional material and the solid dispersant particles are uniformly mixed, and deionized water is added, and the mixture is stirred at a constant temperature to obtain a uniform mixture;

[0014] a2 a1 obtained mixture was stirred and mixed with butyl acrylate and ultrasonically dispersed to obtain component A;

[0015] a3. The pulp is decomposed into a fiber suspension under the action of a fiber decompressor and placed in a pulping tank;

[0016] a4. The modified MFC is diluted and evenly dispersed into component B using ultrasound and placed in an additive preparation tank;

[0017] a5. Pour component A into the pulping tank, mix the pulp fibers evenly with the pulping tank, and obtain wet embryo 1 by vacuum slurry molding;

[0018] a6. Under the premise of continuous vacuum suction, the wet embryo 1 is transferred to the auxiliary agent preparation tank for single-sided immersion suction to obtain a wet embryo 2;

[0019] a7. Place the obtained wet embryo 2 in a hot pressing mold and perform hot pressing and drying to obtain a finished product.

[0020] The constant temperature conditions described in the above step a1 are: 80-95° C., and the time is 30-60 min.

[0021] The stirring condition in the above step a2 is: 5 to 20 minutes; the ultrasonic dispersion condition is: ultrasonic frequency 40 KHz, ultrasonic time 5 to 10 minutes.

[0022] The deflaking conditions described in the above step a3 are: a fiber deflaker speed of 3000 rpm, a deflaking time of 10 to 20 minutes, and a fiber suspension concentration of 0.02 to 0.5%.

[0023] The modified MFC described in step a4 has a diluted concentration of 0.01-0.05%; the ultrasonic dispersion conditions are: ultrasonic frequency 50 KHz, ultrasonic time 5-10 min.

[0024] The slurry suction molding conditions described in the above step a5 are: vacuum degree 0.04-0.06Mpa, slurry suction time 40-90s.

[0025] The single-sided immersion suction conditions described in the above step a6 are: vacuum degree of 0.06-0.08 MPa, and suction time of 30-60 seconds.

[0026] The hot pressing conditions described in the above step a7 are: upper mold 140-150° C., lower mold 160-190° C., hot pressing pressure 0.5-0.8 MPa, time 90-180 s.

[0027] The present invention mainly has the following beneficial effects:

[0028] 1. The fluorine-free water-proof and oil-proof agent for pulp molded products of the present invention adopts fluorine-free raw materials, is safe and environmentally friendly, and will not produce toxic and harmful substances to the human body. It is a healthy and environmentally friendly water-proof and oil-proof agent.

[0029] 2. The preparation method of the fluorine-free waterproof and oil-proof agent for pulp molded products described in the present invention is simple to operate, and the use method is novel and convenient. It can improve the waterproof and oil-proof performance of pulp molding in a hierarchical and efficient manner without increasing equipment, and the amount of additives used is small, saving production costs.

[0030] 3. The oil-proof grade of the fluorine-free water-proof and oil-proof agent for pulp molded products of the present invention is the highest grade 12, the water contact angle is greater than 120°, and the Cobb water absorption value is less than 10g / m 2 , placed under 95℃ hot water and hot oil conditions for 60 minutes without negative seepage, leakage, or deformation, with excellent waterproof and oil-proof effects; at the same time, the tensile strength of pulp molded products is greater than 58KN / m, the stiffness is greater than 70mN·m, and the friction loss is less than 5g / m 2 , which significantly improves the mechanical strength and surface properties of pulp molded products. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic flow chart of an embodiment of a fluorine-free water and oil resistant agent for pulp molded products. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] Embodiment 1:

[0034] A fluorine-free water and oil resistant agent for pulp molded products is prepared from the following components and mass percentages: 89.5 parts of deionized water, 5 parts of cationic starch, 3 parts of butyl acrylate, 2 parts of kaolin, and 0.5 parts of MFC with an aspect ratio of 50 modified by an alkyl ketene dimer.

[0035] The method of using the fluorine-free water and oil repellent for pulp molding products is as follows:

[0036] (1) 2 parts of kaolin and 5 parts of cationic starch were uniformly mixed, 50 parts of deionized water were added, and the mixture was stirred at a constant temperature of 80° C. for 60 minutes to obtain a mixed solution;

[0037] (2) the mixed solution obtained in (1) was stirred and mixed with 3 parts of butyl acrylate for 5 minutes, and then placed in an ultrasonic disperser with an ultrasonic frequency of 40 kHz for 10 minutes to obtain component A;

[0038] (3) placing the pulp in a fiber defibrator at a rotation speed of 3000 rpm for 10 min, diluting the pulp to a concentration of 0.02% and placing the pulp in a pulping tank;

[0039] (4) 0.5 parts of MFC with an aspect ratio of 50 modified by alkyl ketene dimer was diluted with 39.5 parts of deionized water, and ultrasonicated at 50 kHz to obtain 0.01% of component B, which was placed in an additive preparation tank;

[0040] (5) adding component A to a pulping tank, mixing it evenly with the fiber suspension in the pulping tank, and sucking the pulp for 90 seconds under a vacuum degree of 0.04 MPa to obtain a wet embryo 1;

[0041] (6) The wet embryo 1 is transferred to the auxiliary agent preparation tank, and component B is immersed and sucked on one side under a vacuum degree of 0.08 MPa for 50 seconds to obtain a wet embryo 2;

[0042] (7) The obtained wet embryo 2 is placed in a mold with an upper mold temperature of 140° C., a lower mold temperature of 160° C., and a hot pressing pressure of 0.8 MPa, and hot pressed for 90 seconds to obtain a pulp molded product.

[0043] Results: The oil resistance level is the highest level 12, the water contact angle is 120.8°, and the Cobb60 is 5.2g / m 2, placed under 95℃ hot water and hot oil conditions for 60 minutes without negative seepage, leakage or deformation; tensile strength is 58.28KN / m, stiffness is 70.05mN·m, friction loss is 4.5g / m 2 .

[0044] Embodiment 2:

[0045] A fluorine-free water and oil resistant agent for pulp molded products is prepared from the following components and mass percentages: 86.2 parts of deionized water, 2 parts of PVA, 1 part of butyl acrylate, 5 parts of kaolin, 5 parts of talcum powder, and 0.8 parts of polyamide polyamine-epichlorohydrin resin modified MFC with an aspect ratio of 100.

[0046] The method of using the fluorine-free water and oil repellent for pulp molding products is as follows:

[0047] (1) 5 parts of kaolin, 5 parts of talc and 2 parts of PVA were uniformly mixed, 60 parts of deionized water were added, and the mixture was stirred at a constant temperature of 95° C. for 30 minutes to obtain a mixed solution;

[0048] (2) the mixed solution obtained in (1) was stirred and mixed with 1 part of butyl acrylate for 20 minutes, and then placed in an ultrasonic disperser with an ultrasonic frequency of 40 kHz for 5 minutes to obtain component A;

[0049] (3) placing the pulp in a fiber defibrator at a rotation speed of 3000 rpm for 20 min, diluting the pulp to a concentration of 0.5% and placing the pulp in a pulping tank;

[0050] (4) 0.8 parts of MFC with an aspect ratio of 100 modified by polyamide polyamine-epichlorohydrin resin was diluted with 26.2 parts of deionized water, and ultrasonicated at 50 kHz to obtain 0.03% of component B, which was placed in an auxiliary agent preparation tank;

[0051] (5) adding component A to a pulping tank, mixing it evenly with the fiber suspension in the pulping tank, and sucking the pulp for 70 seconds under a vacuum degree of 0.05 MPa to obtain a wet embryo 1;

[0052] (6) The wet embryo 1 is transferred to the auxiliary agent preparation tank, and component B is immersed and sucked on one side under a vacuum degree of 0.06 MPa for 40 seconds to obtain a wet embryo 2;

[0053] (7) The obtained wet embryo 2 is placed in a mold with an upper mold temperature of 150° C., a lower mold temperature of 190° C., and a hot pressing pressure of 0.5 MPa, and hot pressed for 120 seconds to obtain a pulp molded product.

[0054] Results: The oil resistance level is the highest level 12, the water contact angle is 122.8°, and the Cobb60 is 6.7g / m 2, placed under 95℃ hot water and hot oil conditions for 60 minutes without negative seepage, leakage or deformation; tensile strength is 58.48KN / m, stiffness is 72.13mN·m, friction loss is 4.3g / m 2 .

[0055] Embodiment 3:

[0056] A fluorine-free water-proof and oil-proof agent for pulp molding products is prepared from the following components and mass percentages: 83.5 parts of deionized water, 0.5 parts of CMC, 5 parts of butyl acrylate, 10 parts of mica powder, and 1 part of MFC with an aspect ratio of 150 modified by an alkyl ketene dimer.

[0057] The method of using the fluorine-free water and oil repellent for pulp molding products is as follows:

[0058] (1) 10 parts of mica powder and 0.5 parts of CMC were uniformly mixed, 60 parts of deionized water were added, and the mixture was stirred at a constant temperature of 85° C. for 40 minutes to obtain a mixed solution;

[0059] (2) the mixed solution obtained in (1) was stirred and mixed with 5 parts of butyl acrylate for 10 minutes, and then placed in an ultrasonic disperser with an ultrasonic frequency of 40 kHz for 5 minutes to obtain component A;

[0060] (3) placing the pulp in a fiber defibrator at a rotation speed of 3000 rpm for 15 min, diluting the pulp to a concentration of 0.1% and placing the pulp in a pulping tank;

[0061] (4) diluting 1 part of alkyl ketene dimer-modified MFC with an aspect ratio of 150 with 23.5 parts of deionized water, and ultrasonicating at 50 kHz to obtain 0.05% of component B, which is placed in an additive preparation tank;

[0062] (5) adding component A to a pulping tank, mixing it evenly with the fiber suspension in the pulping tank, and sucking the pulp for 40 seconds under a vacuum degree of 0.06 MPa to obtain a wet embryo 1;

[0063] (6) The wet embryo 1 is transferred to the auxiliary agent preparation tank, and component B is immersed and sucked on one side under a vacuum degree of 0.07 MPa for 50 seconds to obtain a wet embryo 2;

[0064] (7) The obtained wet embryo 2 is placed in a mold with an upper mold temperature of 145° C., a lower mold temperature of 180° C., and a hot pressing pressure of 0.7 MPa, and hot pressed for 180 seconds to obtain a pulp molded product.

[0065] Results: The oil resistance level is the highest level 12, the water contact angle is 124.8°, and the Cobb60 is 7.3g / m 2, placed under 95℃ hot water and hot oil conditions for 60 minutes without negative seepage, leakage or deformation; tensile strength is 58.78KN / m, stiffness is 72.45mN·m, friction loss is 4.2g / m 2 .

[0066] Embodiment 4:

[0067] A fluorine-free water-proof and oil-proof agent for pulp molding products is prepared from the following components and mass percentages: 87.2 parts of deionized water, 1 part of CMC, 3 parts of butyl acrylate, 8 parts of magnesium oxide, and 0.8 part of silane-modified MFC with an aspect ratio of 200.

[0068] The method of using the fluorine-free water and oil repellent for pulp molding products is as follows:

[0069] (1) 8 parts of magnesium oxide and 1 part of CMC were uniformly mixed, 60 parts of deionized water were added, and the mixture was stirred at a constant temperature of 85° C. for 50 minutes to obtain a mixed solution;

[0070] (2) the mixed solution obtained in (1) was stirred and mixed with 3 parts of butyl acrylate for 15 minutes, and then placed in an ultrasonic disperser with an ultrasonic frequency of 40 kHz for 6 minutes to obtain component A;

[0071] (3) placing the pulp in a fiber defibrator at a rotation speed of 3000 rpm for 6 minutes, diluting it to a concentration of 0.2% and placing it in a pulping tank;

[0072] (4) 0.8 parts of silane-modified MFC with an aspect ratio of 200 was diluted with 27.2 parts of deionized water, and ultrasonicated at 50 kHz to obtain 0.04% of component B, which was placed in an additive preparation tank;

[0073] (5) adding component A to a pulping tank, mixing it evenly with the fiber suspension in the pulping tank, and sucking the pulp for 90 seconds under a vacuum degree of 0.06 MPa to obtain a wet embryo 1;

[0074] (6) The wet embryo 1 is transferred to the auxiliary agent preparation tank, and component B is immersed and sucked on one side under a vacuum degree of 0.08 MPa for 60 seconds to obtain a wet embryo 2;

[0075] (7) The obtained wet embryo 2 is placed in a mold with an upper mold temperature of 150° C., a lower mold temperature of 190° C., and a hot pressing pressure of 0.8 MPa, and hot pressed for 160 seconds to obtain a pulp molded product.

[0076] Results: The oil resistance level is the highest level 12, the water contact angle is 124.2°, and the Cobb60 is 7.8g / m 2, placed under 95℃ hot water and hot oil conditions for 60 minutes without negative seepage, leakage or deformation; tensile strength is 58.28KN / m, stiffness is 74.50mN·m, friction loss is 4.6g / m 2 .

[0077] Embodiment 5:

[0078] A fluorine-free water-proof and oil-proof agent for pulp molded products is prepared from the following components and mass percentages: 85.2 parts of deionized water, 1 part of sodium alginate, 5 parts of butyl acrylate, 8 parts of magnesium oxide, and 0.8 part of silane-modified MFC with an aspect ratio of 200.

[0079] The method of using the fluorine-free water and oil repellent for pulp molding products is as follows:

[0080] (1) 8 parts of magnesium oxide and 1 part of sodium alginate were uniformly mixed, 60 parts of deionized water were added, and the mixture was stirred at a constant temperature of 90° C. for 30 minutes to obtain a mixed solution;

[0081] (2) the mixed solution obtained in (1) was stirred and mixed with 5 parts of butyl acrylate for 10 minutes, and then placed in an ultrasonic disperser with an ultrasonic frequency of 40 kHz for 5 minutes to obtain component A;

[0082] (3) placing the pulp in a fiber defibrator at a rotation speed of 3000 rpm for 10 min, diluting the pulp to a concentration of 0.02% and placing the pulp in a pulping tank;

[0083] (4) 0.8 parts of silane-modified MFC with an aspect ratio of 200 was diluted with 25.5 parts of deionized water, and ultrasonicated at 50 kHz to obtain 0.05% of component B, which was placed in an additive preparation tank;

[0084] (5) adding component A to a pulping tank, mixing it evenly with the fiber suspension in the pulping tank, and sucking the pulp for 90 seconds under a vacuum degree of 0.04 MPa to obtain a wet embryo 1;

[0085] (6) The wet embryo 1 is transferred to the auxiliary agent preparation tank, and component B is immersed and sucked on one side under a vacuum degree of 0.06 MPa for 60 seconds to obtain a wet embryo 2;

[0086] (7) The obtained wet embryo 2 is placed in a mold with an upper mold temperature of 150° C., a lower mold temperature of 170° C., and a hot pressing pressure of 0.6 MPa, and hot pressed for 160 seconds to obtain a pulp molded product.

[0087] Results: Oil resistance level is the highest level 12, water contact angle is 121.8°, Cobb60 is 6.5g / m 2, placed under 95℃ hot water and hot oil conditions for 60 minutes without negative seepage, leakage or deformation; tensile strength is 59.20KN / m, stiffness is 71.21mN·m, friction loss is 4.9g / m 2 .

[0088] Embodiment 6:

[0089] A fluorine-free water-proof and oil-proof agent for pulp molded products is prepared from the following components and mass percentages: 89.4 parts of deionized water, 1 part of PVA, 3 parts of butyl acrylate, 6 parts of kaolin, and 0.6 part of MFC with an aspect ratio of 100 modified by an alkyl ketene dimer.

[0090] The method of using the fluorine-free water and oil repellent for pulp molding products is as follows:

[0091] (1) 6 parts of kaolin and 1 part of PVA were uniformly mixed, 60 parts of deionized water were added, and the mixture was stirred at a constant temperature of 85° C. for 45 minutes to obtain a mixed solution;

[0092] (2) the mixed solution obtained in (1) was stirred and mixed with 3 parts of butyl acrylate for 10 minutes, and then placed in an ultrasonic disperser with an ultrasonic frequency of 40 kHz for 10 minutes to obtain component A;

[0093] (3) placing the pulp in a fiber defibrator at a rotation speed of 3000 rpm for 15 min, diluting the pulp to a concentration of 0.2% and placing the pulp in a pulping tank;

[0094] (4) 0.6 parts of alkyl ketene dimer-modified MFC with an aspect ratio of 200 was diluted with 29.4 parts of deionized water, and ultrasonicated at 50 kHz to obtain 0.02% of component B, which was placed in an auxiliary agent preparation tank;

[0095] (5) adding component A to a pulping tank, mixing it evenly with the fiber suspension in the pulping tank, and sucking the pulp for 70 seconds under a vacuum degree of 0.04 MPa to obtain a wet embryo 1;

[0096] (6) The wet embryo 1 is transferred to the auxiliary agent preparation tank, and component B is immersed and sucked on one side under a vacuum degree of 0.07 MPa for 50 seconds to obtain a wet embryo 2;

[0097] (7) The obtained wet embryo 2 is placed in a mold with an upper mold temperature of 140° C., a lower mold temperature of 160° C., and a hot pressing pressure of 0.5 MPa, and hot pressed for 90 seconds to obtain a pulp molded product.

[0098] Results: The oil resistance level is the highest level 12, the water contact angle is 125.8°, and the Cobb60 is 8.5g / m 2, placed under 95℃ hot water and hot oil conditions for 60 minutes without negative seepage, leakage or deformation; tensile strength is 58.28KN / m, stiffness is 71.54mN·m, friction loss is 4.8g / m 2 .

[0099] Comparative Example 1: A water-proof and oil-proof agent is added to the pulp of a pulp molded product, which is made of the following components and mass percentages: 35 parts of component a, 64 parts of component b, and 1 part of component c. Usage:

[0100] (1) placing the pulp in a fiber deflagrator, deflagring at a rotation speed of 3000 rpm for 10 min, diluting the pulp to a concentration of 0.1% and placing the pulp in a pulping tank;

[0101] (2) Add component a to the pulping tank and stir it with the fiber suspension in the pulping tank for 10 minutes to mix evenly;

[0102] (3) Add component b to (2) and stir for 5 minutes;

[0103] (4) Add component c to (3) and stir for 2 minutes;

[0104] (5) subjecting the slurry obtained in (4) to vacuum at a degree of 0.07 MPa for 50 seconds to obtain a wet embryo;

[0105] (6) The obtained wet embryo is placed in a mold with an upper mold temperature of 140° C., a lower mold temperature of 160° C., and a hot pressing pressure of 0.5 MPa, and hot pressed for 90 seconds to obtain a pulp molded product.

[0106] Results: Oil resistance level 5, water contact angle 80.8°, Cobb60 96.5g / m 2 , leakage exists after being placed under 95℃ hot water and hot oil conditions for 30 minutes; tensile strength is 48.78KN / m, stiffness is 51.54mN·m, friction loss is 6.8g / m 2 .

[0107] Comparative Example 2: A waterproof and oil-proof agent is sprayed on the surface of a pulp molded product, which is made of the following components and mass percentages: 65 parts of component a and 35 parts of component b. Usage:

[0108] (1) 65 parts of component a and 35 parts of component b were stirred and mixed for 10 minutes, and then placed in an ultrasonic disperser with an ultrasonic frequency of 50 kHz for 10 minutes;

[0109] (2) diluting the liquid obtained in (1) 50 times;

[0110] (3) spraying the surface of the pulp molded product with the liquid obtained in (2);

[0111] (4) The product obtained in (3) was dried by hot air at 105°C for 10 min.

[0112] Results: Oil resistance level 7, water contact angle 90.8, Cobb60 110.7g / m 2 , there is a liquid leakage point when placed under 95℃ hot water and hot oil conditions for 30 minutes; the tensile strength is 49.78KN / m, the stiffness is 52.54mN·m, and the friction loss is 5.8g / m 2 .

[0113] The fluorine-free water-proof and oil-proof agent for pulp molded products provided by the present invention needs to be prepared by component A and component B; in terms of usage, it needs to be used in conjunction with the vacuum suction process of pulp molding, component A is added to the pulp fiber suspension and then formed by vacuum suction, and then placed in component B for single-sided immersion suction of the pulp molding wet embryo, and finally the wet embryo is hot-pressed to obtain good water-proof and oil-proof properties.

[0114] The fluorine-free water-proof and oil-proof agent for pulp molded products provided by the present invention achieves good water-proof and oil-proof effects on finished products through four components, combined with component A added into the pulp and component B impregnated and sucked on one side: butyl acrylate used in component A provides a "macro environment" with low surface energy; the sheet-like functional material fills the gaps between fibers, prolongs the permeation paths of water, oil and gas, and achieves the effects of enhancing water resistance, oil resistance and water vapor resistance; the dispersant also has the function of an adhesive, which not only makes the sheet-like functional material evenly dispersed in the three-dimensional fiber network structure of pulp molding, but also provides hydrogen bonds to help the sheet-like functional material to be more The fiber is well fixed on the fiber and tightly combined with the fiber to enhance the strength and tightness of the pulp molding; the addition of component A in the pulp makes the pulp molding body have a certain waterproof and oil-proof effect, reducing the use of high-cost modified MFC in the single-sided impregnation and suction component B. The process of single-sided impregnation and suction of component B makes the surface of the pulp molded product further refined. MFC has excellent oil-proof effect, but poor waterproof effect. Therefore, the present invention adopts hydrophobic modified MFC for the single-sided impregnation and suction stage, and greatly improves the waterproof and oil-proof performance by adsorbing a layer of hydrophobic modified MFC on the surface of the pulp molding. This novel use of functional additives in the present invention enables pulp molding to achieve hierarchical water and oil blocking in the Z direction, which not only saves the amount of additives, but also efficiently improves the barrier performance, achieving a synergistic effect. The pulp molded product obtained by using the fluorine-free water and oil resistant agent of the present invention has an oil resistance grade of up to grade 12, a water contact angle of greater than 120°, no negative seepage, no leakage, and no deformation after being exposed to 95°C hot water for 60 minutes, and the mechanical strength of the pulp molded product fully meets the requirements of GB / T 36787-2018, while having excellent surface performance.

[0115] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and changes can be made based on the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can better understand and use the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A fluorine-free water and oil repellent for pulp molded products, characterized in that: It is made of the following components and mass percentages: 50-90 parts of deionized water, 0.5-5 parts of dispersant, 1-5 parts of butyl acrylate, 2-10 parts of sheet functional material, and 0.1-1 part of modified MFC; The flaky functional material is one or more of talc, kaolin, mica powder and magnesium oxide; The modified MFC is one of alkyl ketene dimer, silane series or polyamide polyamine-epichlorohydrin resin modified microfibrils; The dispersant is one of CMC, cationic starch, PVA and sodium alginate.

2. The fluorine-free water and oil resistant agent for pulp molded products according to claim 1, characterized in that: The modified MFC has an aspect ratio of 50-200.

3. The method for using the fluorine-free water and oil resistant agent for pulp molded products according to any one of claims 1 to 2, characterized in that: The following steps are involved: a1. The sheet-like functional material and the dispersant are uniformly mixed, and deionized water is added, and the mixture is stirred at a constant temperature to obtain a uniform mixture; a2 a1 obtained mixture was stirred and mixed with butyl acrylate and ultrasonically dispersed to obtain component A; a3. The pulp is decomposed into a fiber suspension under the action of a fiber decompressor and placed in a pulping tank; a4. The modified MFC is diluted and evenly dispersed into component B using ultrasound and placed in an additive preparation tank; a5. Pour component A into the pulping tank, mix the pulp fibers evenly with the pulping tank, and obtain wet embryo 1 by vacuum slurry molding; a6. Under the premise of continuous vacuum suction, the wet embryo 1 is transferred to the auxiliary agent preparation tank for single-sided immersion suction to obtain a wet embryo 2; a7. Place the obtained wet embryo 2 in a hot pressing mold and perform hot pressing and drying to obtain a finished product.

4. The method for using the fluorine-free water and oil resistant agent for pulp molded products according to claim 3, characterized in that: The constant temperature conditions described in step a1 are: 80-95° C., time 30-60 min.

5. The method for using the fluorine-free water and oil resistant agent for pulp molded products according to claim 3, characterized in that: The stirring condition in step a2 is: 5 to 20 minutes; the ultrasonic dispersion condition is: ultrasonic frequency 40 KHz, ultrasonic time 5 to 10 minutes.

6. The method for using the fluorine-free water and oil resistant agent for pulp molded products according to claim 3, characterized in that: The deflaking conditions in step a3 are: a fiber deflaker speed of 3000 rpm, a deflaking time of 10 to 20 min, and a fiber suspension concentration of 0.02 to 0.5%.

7. The method for using the fluorine-free water and oil resistant agent for pulp molded products according to claim 3, characterized in that: The modified MFC in step a4 has a concentration of 0.01-0.05% after dilution; the ultrasonic dispersion conditions are: ultrasonic frequency 50 KHz, ultrasonic time 5-10 min.

8. The method for using the fluorine-free water and oil resistant agent for pulp molded products according to claim 3, characterized in that: The slurry suction molding conditions described in step a5 are: vacuum degree 0.04-0.06Mpa, slurry suction time 40-90s.

9. The method for using the fluorine-free water and oil resistant agent for pulp molded products according to claim 3, characterized in that: The single-sided immersion and suction conditions described in step a6 are: vacuum degree 0.06-0.08 MPa, slurry suction time 30-60 s.

10. The method for using the fluorine-free water and oil resistant agent for pulp molded products according to claim 3, characterized in that: The hot pressing conditions described in step a7 are: upper mold 140-150° C., lower mold 160-190° C., hot pressing pressure 0.5-0.8 MPa, and time 90-180 s.

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