Low temperature resistant, fluorine-free, oil repellent agent, composition, pulp molded article and method of making

Abstract

The application belongs to the field of new materials, and discloses a low-temperature-resistant fluorine-free oil-proof agent, which is an emulsion composed of wax, cationic starch, dispersant and water; the dispersant is a styrene-maleic anhydride copolymer; the content of the wax is 25-40 wt%; the content of the cationic starch is 1-4.5 wt%; and the content of the dispersant is 0.5-7 wt%. The oil-proof agent uses the styrene-maleic anhydride copolymer as the dispersant, and the wax and the cationic starch jointly act to realize low-temperature oil-proof and improve the low-temperature storage stability. Meanwhile, the application also discloses a preparation method and application of the low-temperature-resistant fluorine-free oil-proof agent.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of new materials, in particular to a low-temperature-resistant fluorine-free oil repellent, a composition, a pulp molded product and a preparation method thereof. BACKGROUND

[0002] With the rapid development of the national economy, environmental awareness has gradually increased. Pulp molded products are green environmental protection products strongly recommended by the global environmental protection bureau. In the processing process, there are no harmful substances discharged in the processes of pulp, adsorption forming, drying and shaping, etc. to cause environmental pollution.

[0003] It is urgently needed to develop a non-toxic, environmentally friendly fluorine-free oil repellent.

[0004] In the prior art, the following documents about fluorine-free oil repellents are available:

[0005] Patent application with publication number CN119531177A, subjecting to a bio-based fluorine-free oil repellent and a preparation process thereof;

[0006] Patent application with publication number CN119639345A, subjecting to an environmentally friendly degradable fluorine-free oil and fat resistant agent, a preparation method and application thereof;

[0007] Patent application with publication number CN119194900B, subjecting to a fluorine-free oil repellent, a preparation method and application in pulp molding manufacturing.

[0008] The above-mentioned schemes all use wax and cationic starch as the main materials of the oil repellent.

[0009] In many patent applications of fluorine-free oil repellents in the field, there is no clear evidence that the fluorine-free oil repellents recorded in the market or literature have obvious advantages in low-temperature oil resistance and low-temperature-resistant oil resistance attenuation. SUMMARY

[0010] The purpose of the present application is to provide a low-temperature-resistant fluorine-free oil repellent. The oil repellent uses styrene-maleic anhydride copolymer as a dispersant, which works together with wax and cationic starch to achieve the purpose of low-temperature oil resistance and improve the low-temperature storage stability.

[0011] At the same time, the present application also discloses a preparation method and application of the low-temperature-resistant fluorine-free oil repellent.

[0012] To achieve the above-mentioned purpose, the present application discloses:

[0013] A low-temperature-resistant fluorine-free oil repellent, which is an emulsion composed of wax, cationic starch, dispersant and water; the dispersant is styrene-maleic anhydride copolymer;

[0014] The content of the wax is 25-40wt%;

[0015] The content of the cationic starch is 1-4.5wt%;

[0016] The content of the dispersant is 0.5-7wt%.

[0017] Preferably, the content of the wax is 30-35wt%;

[0018] The content of the cationic starch is 3-4.5wt%;

[0019] The content of the dispersant is 1-2wt%.

[0020] The most obvious difference between the present application and the prior art is that the present application uses styrene-maleic anhydride copolymer as a dispersant, which can effectively improve the low-temperature impermeability of paper products.

[0021] It should be noted that the oil-proof agent of the present application can achieve excellent oil-proof effect when used alone; when used together with a cationic aluminum salt in the papermaking process, it can exhibit more excellent performance.

[0022] From the perspective of the oil-proof agent of the present application, the cationic group of the cationic starch carries a positive charge, so that the oil-proof agent itself has a sufficient positive charge and can be tightly combined with the fiber; the wax has a low surface energy, and under the action of the emulsifier, it forms a stable emulsion with the starch, and under high-speed shearing, the emulsion particle size reaches 0.5-2μm, which can penetrate into the voids of the pulp fiber as much as possible, thereby forming a dense film between the fiber gaps; the combination of the styrene-maleic anhydride copolymer dispersant, or further combined with the cationic aluminum salt, can make the oil-proof grade of the pulp molded product reach Kit 5 or above, and the pulp molded product can be prevented from permeating for 30min under the condition of oil-proofing at 60-20℃.

[0023] The oil-proof scheme of the present application has a simple preparation and production process, is beneficial to large-scale production, and has no fluorine and harmful substance output in the production and preparation process, and can ensure more than 60 days of storage at low temperature 20℃, which is more resistant to low-temperature decay than the wax-based oil-proof agent on the market.

[0024] In the above low-temperature resistant fluorine-free oil-proof agent, the cationic starch has a tertiary amino group or a quaternary ammonium group, and the nitrogen content of the cationic starch is between 0.2-1wt%, preferably between 0.4-0.5wt%.

[0025] In the above low-temperature resistant fluorine-free oil-proof agent, the wax is at least one of microcrystalline wax, Fischer-Tropsch wax, polyethylene wax, polypropylene wax, polypropylene wax, and paraffin wax.

[0026] In the low-temperature resistant fluorine-free oil repellent described above, the paraffin is an alkane mixture with carbon atom number of 18-50; the styrene-maleic anhydride copolymer is a regular copolymer obtained by block copolymerization of styrene and maleic anhydride, with molecular weight of 0.2-20,000, preferably, the molecular weight of the styrene-maleic anhydride copolymer is 5,000-9,000.

[0027] As some optional paraffin, the paraffin commonly used in the art can meet the basic requirements of the present application, such as No. 52, 54, 56, 58, 60, 62, 64, 66, 68 and 70, etc.

[0028] Meanwhile, the present application also discloses a preparation method of the fluorine-free oil repellent as described above, which comprises the following steps:

[0029] The homogenization temperature is 85-90℃, and the homogenization pressure is 20-40Mpa, and the homogenization operation is completed by natural cooling.

[0030] In the preparation method described above, the method specifically comprises the following steps: adding the gelatinized cationic starch and the dispersion agent aqueous solution containing the dispersion agent into the molten wax, mixing and homogenizing to form an emulsion.

[0031] In addition, the present application also includes a composition comprising the fluorine-free oil repellent as described above, a cationic aluminum salt and an alkyl alkene ketone dimer.

[0032] The weight ratio of the fluorine-free oil repellent, the cationic aluminum salt and the alkyl alkene ketone dimer is 3-5: 0.25-1: 1.9-2.8.

[0033] Preferably, the weight ratio of the fluorine-free oil repellent, the cationic aluminum salt and the alkyl alkene ketone dimer is 3-5: 0.5-1: 2.

[0034] The cationic aluminum salt is a water-soluble inorganic high-molecular positive trivalent aluminum salt polymer.

[0035] In the composition described above, the cationic aluminum salt has the following general formula:

[0036] Al2(OH) x Cl y ;

[0037] x=2-5; y=1-4.

[0038] In addition, the present application also discloses a method for preparing a paper pulp molded product by using the composition as described above, which comprises the following steps:

[0039] Step 1: dilute the pulp slurry with beating degree of 20-30°SR to a pulp concentration of 0.3-0.8wt%;

[0040] Step 2: add the cationic aluminum salt first, then the alkyl ketene dimer, and finally the fluorine-free oil repellent to the pulp slurry obtained in Step 1, and mix under stirring;

[0041] Step 3: inject the pulp slurry obtained in Step 2 into a mold, and dehydrate to obtain a wet embryo with a moisture content of 50-76wt%;

[0042] Step 4: dry and shape the wet embryo to obtain the pulp molded product.

[0043] In the above preparation method, the use amount of each raw material is: 97-99wt% of pulp fibers, 0.25-1wt% of cationic aluminum salt, 1.9-2.8wt% of alkyl ketene dimer, and 3-5wt% of wax-based fluorine-free oil repellent, based on 100% of the dry weight of the pulp molded product;

[0044] Preferably, the use amount of each raw material is: 97-99wt% of pulp fibers, 0.5-1wt% of cationic aluminum salt, 2wt% of alkyl ketene dimer, and 3-5wt% of wax-based fluorine-free oil repellent;

[0045] The pulp fibers in the pulp slurry are one of or a mixture of sugar cane fibers and bamboo pulp fibers.

[0046] Finally, the present application also discloses a pulp molded product prepared by the above method.

[0047] The present application has at least the following beneficial effects:

[0048] The cationic groups of the cationic starch carry positive charges, so that the oil repellent itself has sufficient positive charges, and can be tightly combined with the fibers; the wax has a low surface energy, and forms a stable emulsion with the starch under the action of the emulsifier, so that the emulsion particle size reaches 0.5-2μm under high-speed shearing, and can penetrate into the interstices of the pulp fibers as much as possible, so as to form a dense film between the fiber interstices;

[0049] In combination with the styrene-maleic anhydride copolymer dispersant, or further in combination with the cationic aluminum salt, the oil repellency grade of the pulp molded product can reach Kit 5 or above, and the pulp molded product can be prevented from penetrating for 30min under the condition of oil repellency of 60-20℃.

[0050] The oil-proof solution of the application has simple preparation and production process, is beneficial to large-scale production, and has no fluorine and harmful substance output in the production process. The molded product can be stored at low temperature of 20℃ for more than 60 days, and is more resistant to low-temperature attenuation than the wax-based oil-proof agent on the market. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 is the off-machine oil-proof performance picture of different temperatures of each case;

[0052] Figure 2 is the oil-proof performance picture after different storage times of each case. DETAILED DESCRIPTION

[0053] The application will be described clearly and completely below by combining the embodiments of the application. In the description of the application, it should be noted that the specific conditions not noted in the embodiments are carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments not noted by the manufacturer are all conventional products that can be obtained by market purchase. In the embodiments of the application, the parts are all weight parts unless otherwise specified.

[0054] Example 1

[0055] Preparation of the wax-based fluorine-free oil-proof agent:

[0056] The modified starch 8g and water 72g are gelatinized at 90℃ and a rotation speed of 300 RPM / min, and the reaction time is 1h.

[0057] The dispersant 4g and water 56g are dissolved under stirring at a rotation speed of 500 RPM / min, a temperature of 85℃ and an alkaline condition of PH 8.5-9.5, and the stirring time is 2h.

[0058] The 60g of 70# wax is dissolved at 85℃.

[0059] After the wax is completely dissolved, the dissolved modified starch and dispersant are added into the wax solution under stirring at 85℃ and a rotation speed of 500 RPM / min for 15min. Then the material temperature is raised to 85℃, the high-pressure homogenizer is preheated with hot water, and the emulsion is passed through the high-pressure homogenizer at a pressure of 40Mpa. After the high-pressure homogenization, the material is naturally cooled to 35℃ at a rotation speed of 500 RPM / min, so as to obtain the stable wax-based fluorine-free oil-proof agent with small particle size.

[0060] In this embodiment, the modified starch is corn starch with nitrogen content of 0.4%.

[0061] The dispersant is a regular copolymer obtained by copolymerization of styrene and maleic anhydride, and the weight average molecular weight is 9000.

[0062] Preparation of pulp molded product:

[0063] The sugarcane pulp board and the bamboo pulp board are mixed in a weight ratio of 8:2, and are disintegrated and ground at a pulp concentration of 2wt%, to obtain a pulp slurry with a degree of beating of 20-30°SR, and the weight of the sugarcane pulp board and the bamboo pulp board is 99% of the dry weight of the pulp molded product;

[0064] The disintegrated pulp slurry is diluted to 0.5wt% by adding white water into the circulation system, and 1wt% of a cationic aluminum salt solution (the concentration of the cationic aluminum salt is 50%) is first added under stirring at a stirring speed of 100-500RPM, and stirring is performed for 5min, then 2wt% of alkyl alkene ketone dimer (AKD) is added, and stirring is performed for 5min, and finally 5wt% of a wax-based fluorine-free oil-proof agent is added, and stirring is performed for 5min, and then a pulp molded product with a water content of 8% is obtained through wet embryo molding (vacuum degree: -0.03-0.08Mpa) and baking (upper mold temperature: 160℃, lower mold temperature: 180℃). In this embodiment, the cationic aluminum salt is Al2(OH)5Cl;

[0065] It should be noted that the above percentage is based on 100% of the dry weight of the pulp molded product.

[0066] Example 2

[0067] Preparation of wax-based fluorine-free oil-proof agent

[0068] 64g of 70# wax is dissolved at 85℃.

[0069] 6g of modified starch and 54g of water are gelatinized at 90℃ and a stirring speed of 300RPM / min, and the reaction time is 1h.

[0070] 2g of dispersant and 74g of water are dissolved under stirring at a stirring speed of 500RPM / min, a temperature of 85℃, and an alkaline condition of PH 8.5-9.5, and the stirring time is 2h.

[0071] After the wax is completely dissolved, the dissolved modified starch and the dispersant are respectively added into the wax solution under a stirring speed of 500RPM at 85℃, and the mixture is stirred for 15min.

[0072] Then the material temperature is increased to 90℃, a high-pressure homogenizer is preheated with hot water, and the emulsion is passed through the high-pressure homogenizer while it is hot.

[0073] After the high-pressure homogenization, the material is naturally cooled to 35℃ under a stirring speed of 500RPM / min, so as to obtain a stable wax-based fluorine-free oil-proof agent with a small particle size.

[0074] In this embodiment, the modified starch is hydrolyzed potato starch with nitrogen content of 0.5%. The dispersant is a styrene-maleic anhydride copolymer, a regular copolymer obtained by copolymerization of styrene and maleic anhydride, and the weight average molecular weight is 5000.

[0075] Preparation of the pulp molded product:

[0076] The sugarcane pulp board and the bamboo pulp board are mixed in a weight ratio of 8:2, and are disintegrated and ground at a pulp concentration of 2 wt%, to obtain a slurry with a degree of beating of 20-30°SR, and the weight of the sugarcane pulp board and the bamboo pulp board is 98% of the dry weight of the pulp molded product.

[0077] The disintegrated slurry is diluted to 0.3% with white water in the circulation system, and 2% of a cationic aluminum salt (concentration of the cationic aluminum salt is 50%) is added under stirring at a speed of 100-500 RPM, and then 2% of alkyl alkene ketone dimer (AKD) is added and stirred for 5 min, and finally 4% of a wax-based fluorine-free oil-proof agent is added and stirred for 5 min, and then the pulp molded product with a moisture content of 8% is obtained through wet embryo molding (vacuum degree is -0.03-0.08 MPa) and baking (upper mold temperature is 160°C, and lower mold temperature is 180°C).

[0078] In this embodiment, the cationic aluminum salt is Al2(OH)3Cl3.

[0079] Example 3

[0080] Preparation of the wax-based fluorine-free oil-proof agent

[0081] 70 g of 70# wax is dissolved at 85°C.

[0082] 9 g of modified starch and 81 g of water are gelatinized at 90°C and a stirring speed of 300 RPM / min, and the reaction time is 1 h.

[0083] 3 g of dispersant and 37 g of water are dissolved under stirring at a stirring speed of 500 RPM / min and a temperature of 85°C, and the alkaline condition is PH 8.5-9.5, and the stirring time is 2 h.

[0084] After the wax is completely dissolved, the dissolved modified starch and the dispersant are added into the wax solution under a stirring speed of 500 RPM at 85°C, and the mixture is stirred for 15 min.

[0085] The temperature of the material is then increased to 90°C, and the high-pressure homogenizer is preheated with hot water, and then the emulsion is passed through the high-pressure homogenizer at a pressure of 40 MPa.

[0086] After the high-pressure homogenization, the material is naturally cooled to 35°C at a stirring speed of 500 RPM / min, so as to obtain the stable wax-based fluorine-free oil-proof agent with small particle size.

[0087] In this embodiment, the modified starch is hydrolyzed potato starch with nitrogen content of 0.5%. The dispersant is a styrene-maleic anhydride copolymer, a regular copolymer obtained by copolymerization of styrene and maleic anhydride, with a weight average molecular weight of 5000.

[0088] Preparation of the pulp molded product:

[0089] The sugarcane pulp board and the bamboo pulp board are mixed at a ratio of 6:4, and are then disintegrated and ground at a pulp concentration of 2% to obtain a slurry with a degree of beating of 20-30°SR. The weight of the sugarcane pulp board and the bamboo pulp board is 97% of the dry weight of the pulp molded product.

[0090] The disintegrated slurry is diluted to 0.8% with white water in the circulation system. Under stirring at a speed of 100-500 RPM, 2% of a cationic aluminum salt (concentration of the cationic aluminum salt is 50%) is first added, and stirred for 5 min. Then, 2% of an alkyl alkene ketene dimer (AKD) is added, and stirred for 5 min. Finally, 3% of a wax-based fluorine-free oil-proof agent is added, and stirred for 5 min. After wet blank forming (vacuum degree is -0.03-0.08 MPa) and baking (upper mold temperature is 160°C, and lower mold temperature is 180°C), a pulp molded product with a water content of 8% is obtained. In this embodiment, the cationic aluminum salt is Al2(OH)2Cl4.

[0091] Example 4

[0092] Preparation of the wax-based fluorine-free oil-proof agent:

[0093] 2 g of the modified starch and 48 g of water are pasted at 90°C and a stirring speed of 300 RPM / min, and the reaction is carried out for 1 h.

[0094] 1 g of the dispersant and 99 g of water are dissolved under stirring at a stirring speed of 500 RPM / min, a temperature of 85°C, and an alkaline condition of PH 8.5-9.5, and the stirring is carried out for 2 h.

[0095] 50 g of 68# wax is dissolved at 85°C.

[0096] After the wax is completely dissolved, the dissolved modified starch and the dispersant are added into the wax solution under a temperature of 85°C and a stirring speed of 500 RPM, and are mixed and stirred for 15 min. Then, the material temperature is increased to 85°C, a high-pressure homogenizer is preheated with hot water, and the emulsion is passed through the high-pressure homogenizer while being hot. The pressure is 40 MPa. After the high-pressure homogenization, the material is naturally cooled to 35°C under a stirring speed of 500 RPM / min, so that the wax-based fluorine-free oil-proof agent with stable and small particle size is obtained.

[0097] In this embodiment, the modified starch is hydrolyzed potato starch with nitrogen content of 0.5%. The dispersant is a styrene-maleic anhydride copolymer, a regular copolymer obtained by copolymerization of styrene and maleic anhydride, and the weight average molecular weight is 5000.

[0098] Preparation of the pulp molded product:

[0099] The sugarcane pulp board and the wood pulp board are mixed in a weight ratio of 9:1, and are disintegrated and ground at a pulp concentration of 2 wt%, to obtain a slurry with a degree of beating of 20-30°SR. The weight of the sugarcane pulp board and the wood pulp board is 99% of the dry weight of the pulp molded product.

[0100] The disintegrated slurry is diluted to 0.8 wt% by adding white water into the circulation system. Under a stirring speed of 100-500 RPM, 1.9 wt% of alkyl ketene dimer (AKD) is first added, stirred for 5 min, then 5 wt% of the wax-based fluorine-free oil-proof agent is added, stirred for 5 min, and finally 0.5 wt% of the cationic aluminum salt solution (the concentration of the cationic aluminum salt is 50%) is added, stirred for 5 min. After wet blank forming (vacuum degree -0.03-0.08 MPa) and baking (upper mold temperature 160°C, lower mold temperature 180°C), the pulp molded product with a water content of 8% is obtained. In this embodiment, the cationic aluminum salt is Al2(OH)5Cl;

[0101] It should be noted that the above percentage is based on the dry weight of the pulp molded product as 100%.

[0102] Example 5

[0103] Preparation of the wax-based fluorine-free oil-proof agent:

[0104] The modified starch 6 g and water 54 g are gelatinized at 90°C and a stirring speed of 300 RPM / min, and the reaction time is 1 h.

[0105] The dispersant 14 g and water 46 g are dissolved under a stirring speed of 500 RPM / min, a temperature of 85°C, and an alkaline condition of PH 8.5-9.5, and the stirring time is 2 h.

[0106] The 80 g of 60# wax is dissolved at 85°C.

[0107] After the wax is completely dissolved, the dissolved modified starch and the dispersant are added into the wax solution under a stirring speed of 500 RPM at 85°C, and mixed and stirred for 15 min. Then the material temperature is raised to 85°C, the high-pressure homogenizer is preheated with hot water, and the emulsion is passed through the high-pressure homogenizer while hot, at a pressure of 40 MPa. After high-pressure homogenization, the material is naturally cooled to 35°C under a stirring speed of 500 RPM / min, so as to obtain a stable wax-based fluorine-free oil-proof agent with small particle size.

[0108] In this embodiment, the modified starch is hydrolyzed potato starch with nitrogen content of 0.5%. The dispersant is a styrene-maleic anhydride copolymer, a regular copolymer obtained by copolymerization of styrene and maleic anhydride, with a weight average molecular weight of 5000.

[0109] Preparation of the pulp molded product:

[0110] The sugarcane pulp board and the wood pulp board are mixed in a weight ratio of 8:2, and are disintegrated and ground at a pulp concentration of 2 wt%, to obtain a slurry with a degree of beating of 20-30°SR. The weight of the sugarcane pulp board and the wood pulp board is 98% of the dry weight of the pulp molded product.

[0111] The disintegrated slurry is diluted to 0.8 wt% by adding white water into the circulation system. At a stirring speed of 100-500 RPM, 2.8 wt% of alkyl ketene dimer (AKD) is first added, stirred for 5 min, then 4 wt% of the wax-based fluorine-free oil-proof agent is added, stirred for 5 min, and finally 0.9 wt% of the cationic aluminum salt solution (the concentration of the cationic aluminum salt is 50%) is added, stirred for 5 min. After wet blank forming (vacuum degree -0.03-0.08 MPa) and baking (upper mold temperature 160°C, lower mold temperature 180°C), a pulp molded product with a water content of 8% is obtained. In this embodiment, the cationic aluminum salt is Al2(OH)5Cl.

[0112] It should be noted that the above percentage is based on the dry weight of the pulp molded product being 100%.

[0113] Example 6

[0114] Preparation of the wax-based fluorine-free oil-proof agent:

[0115] 8 g of modified starch and 72 g of water are pasted at 90°C and a stirring speed of 300 RPM / min, and the reaction time is 1 h.

[0116] 4 g of dispersant and 56 g of water are dissolved under stirring at a stirring speed of 500 RPM / min, a temperature of 85°C, and an alkaline condition of PH 8.5-9.5, and the stirring time is 2 h.

[0117] 60 g of 80# microcrystalline wax is dissolved at 95°C.

[0118] After the wax is completely dissolved, the dissolved modified starch and the dispersant are added into the wax solution at 95°C and a stirring speed of 500 RPM, and mixed and stirred for 15 min. Then the material temperature is raised to 95°C, a high-pressure homogenizer is preheated with hot water, and the emulsion is passed through the high-pressure homogenizer while hot. The pressure is 40 MPa. After high-pressure homogenization, the material is naturally cooled to 35°C at a stirring speed of 500 RPM / min, so as to obtain a stable wax-based fluorine-free oil-proof agent with a small particle size.

[0119] In this embodiment, the modified starch is hydrolyzed potato starch with nitrogen content of 0.5%. The dispersant is a styrene-maleic anhydride copolymer, a regular copolymer obtained by copolymerization of styrene and maleic anhydride, with a weight average molecular weight of 5000.

[0120] Preparation of the pulp molded product:

[0121] The sugarcane pulp board and the bamboo pulp board are mixed in a weight ratio of 8:2, and are disintegrated and ground at a pulp concentration of 2 wt%, to obtain a slurry with a degree of beating of 20-30°SR. The weight of the sugarcane pulp board and the bamboo pulp board is 99% of the dry weight of the pulp molded product.

[0122] The disintegrated slurry is diluted to 0.8 wt% by adding white water into the circulation system. Under a stirring speed of 100-500 RPM, 1 wt% of a cationic aluminum salt solution (the cationic aluminum salt concentration is 50%) is first added, stirred for 5 min, then 2 wt% of alkyl alkene ketone dimer (AKD) is added, stirred for 5 min, and finally 5 wt% of a wax-based fluorine-free oil-proof agent is added, stirred for 5 min. After wet embryo molding (vacuum degree -0.03-0.08 MPa) and baking (upper mold temperature 160°C, lower mold temperature 180°C), a pulp molded product with a water content of 8% is obtained. In this embodiment, the cationic aluminum salt is Al2(OH)5Cl;

[0123] It should be noted that the above percentage is based on the dry weight of the pulp molded product being 100%.

[0124] Example 7

[0125] Preparation of the wax-based fluorine-free oil-proof agent:

[0126] 8 g of modified starch and 72 g of water are pasted at 90°C and a stirring speed of 300 RPM / min, and the reaction time is 1 h.

[0127] 4 g of dispersant and 56 g of water are dissolved under a stirring speed of 500 RPM / min, a temperature of 85°C, and an alkaline condition of PH 8.5-9.5, and the stirring time is 2 h.

[0128] 60 g of 80# oxidized polyethylene wax is dissolved at 95°C.

[0129] After the wax is completely dissolved, the modified starch and the dispersant are added into the wax solution at 95°C and 500 RPM, and mixed for 15 minutes. The temperature of the mixture is then raised to 95°C, and the high-pressure homogenizer is preheated with hot water. The emulsion is then passed through the high-pressure homogenizer at a pressure of 40 MPa. After the high-pressure homogenization, the material is naturally cooled to 35°C at a rotation speed of 500 RPM / min, thereby obtaining a stable and small-particle-size wax-based fluorine-free oil-proof agent.

[0130] In this embodiment, the modified starch is hydrolyzed potato starch with a nitrogen content of 0.5%. The dispersant is a regular copolymer of styrene-maleic anhydride, which is obtained by copolymerization of styrene and maleic anhydride, and has a weight average molecular weight of 5000.

[0131] Preparation of the pulp molded product:

[0132] The sugarcane pulp board and the bamboo pulp board are mixed in a weight ratio of 8:2, and are disintegrated and ground at a pulp concentration of 2 wt% to obtain a slurry with a degree of beating of 20-30°SR. The weight of the sugarcane pulp board and the bamboo pulp board is 99% of the dry weight of the pulp molded product.

[0133] The disintegrated slurry is diluted to 0.8 wt% with white water in a circulating system, and 1 wt% of a cationic aluminum salt solution (the cationic aluminum salt has a concentration of 50%) is added under stirring at a rotation speed of 100-500 RPM for 5 minutes. Then, 2 wt% of alkyl alkene ketone dimer (AKD) is added and stirred for 5 minutes. Finally, 5 wt% of the wax-based fluorine-free oil-proof agent is added and stirred for 5 minutes. After wet blank forming (vacuum degree: -0.03-0.08 MPa) and baking (upper mold temperature: 160°C, lower mold temperature: 180°C), a pulp molded product with a water content of 8% is obtained. In this embodiment, the cationic aluminum salt is Al2(OH)5Cl.

[0134] It should be noted that the above-mentioned percentage is based on the dry weight of the pulp molded product being 100%.

[0135] Example 8

[0136] Preparation of the wax-based fluorine-free oil-proof agent:

[0137] 8 g of modified starch and 72 g of water are mixed at 90°C and a rotation speed of 300 RPM / min to gelatinize the modified starch, and the reaction time is 1 h.

[0138] 4 g of the dispersant and 56 g of water are mixed at a rotation speed of 500 RPM / min, a temperature of 85°C, and an alkaline condition of PH 8.5-9.5 to dissolve the dispersant, and the stirring time is 2 h.

[0139] 60 g of 70# wax is dissolved at 85°C.

[0140] After the wax is completely dissolved, the dissolved modified starch and dispersant are added into the wax solution at 85°C and 500 RPM, and mixed and stirred for 15 min. Then the material temperature is raised to 85°C, the high-pressure homogenizer is preheated with hot water, and the emulsion is passed through the high-pressure homogenizer while hot, at a pressure of 40 MPa. After high-pressure homogenization, the material is naturally cooled to 35°C at a stirring speed of 500 RPM / min, thereby obtaining a stable and small-particle-size wax-based fluorine-free oil-proof agent.

[0141] In this embodiment, the modified starch is hydrolyzed potato starch with a nitrogen content of 0.5%. The dispersant is a regular copolymer of styrene-maleic anhydride, which is obtained by copolymerization of styrene and maleic anhydride, and has a weight average molecular weight of 5000.

[0142] Preparation of a pulp molded product:

[0143] Sugarcane pulp board and bamboo pulp board are mixed in a weight ratio of 8:2, and are subjected to pulping and refining at a pulp concentration of 2 wt%, to obtain a slurry with a degree of beating of 20-30°SR. The weight of the sugarcane pulp board and the bamboo pulp board is 99% of the dry weight of the pulp molded product.

[0144] The broken slurry is diluted to 0.8 wt% with white water in a circulating system, 2 wt% alkyl alkene ketone dimer (AKD) is added under stirring at a speed of 100-500 RPM, and stirred for 5 min, then 5 wt% wax-based fluorine-free oil-proof agent is added, stirred for 5 min, and then a pulp molded product with a moisture content of 8% is obtained through wet blank forming (vacuum degree -0.03-0.08 MPa) and baking (upper mold temperature 160°C, lower mold temperature 180°C).

[0145] It should be noted that the above percentage is based on the dry weight of the pulp molded product being 100%.

[0146] Example 9

[0147] Preparation of a wax-based fluorine-free oil-proof agent

[0148] 64 g of 70# wax is dissolved at 85°C.

[0149] 6 g of modified starch and 54 g of water are gelatinized at 90°C and a stirring speed of 300 RPM / min, and the reaction time is 1 h.

[0150] 2 g of dispersant and 74 g of water are dissolved under stirring at a stirring speed of 500 RPM / min and a temperature of 85°C, and the pH is 8.5-9.5 in an alkaline condition, and the stirring time is 2 h.

[0151] After the wax is completely dissolved, the dissolved modified starch and dispersant are added into the wax solution at 85°C and 500 RPM, and mixed and stirred for 15 min.

[0152] The temperature of the material is then raised to 90°C, and the high-pressure homogenizer is preheated with hot water. The emulsion is then passed through the high-pressure homogenizer while hot, at a pressure of 40 MPa.

[0153] The material after high-pressure homogenization is naturally cooled to 35°C at a rotation speed of 500 RPM / min, thereby obtaining a stable and small-particle-size wax-based fluorine-free oil repellent.

[0154] In this embodiment, the modified starch is hydrolyzed potato starch with a nitrogen content of 0.5%. The dispersant is a regular copolymer of styrene-maleic anhydride, which is obtained by copolymerization of styrene and maleic anhydride, and has a weight average molecular weight of 5000.

[0155] Preparation of the pulp molded product:

[0156] The bagasse pulp board and the bamboo pulp board are mixed in a weight ratio of 8:2, and are disintegrated and ground at a pulp concentration of 2 wt%, to obtain a pulp slurry with a degree of beating of 20-30°SR. The weight of the bagasse pulp board and the bamboo pulp board is 98% of the dry weight of the pulp molded product.

[0157] The disintegrated pulp slurry is diluted to 0.3% with white water in the circulation system. At a stirring speed of 100-500 RPM, 2% of alkyl alkene ketone dimer (AKD) is first added and stirred for 5 min, and then 4% of the wax-based fluorine-free oil repellent is added and stirred for 5 min. The pulp molded product with a moisture content of 8% is obtained after wet blank forming (vacuum degree -0.03-0.08 MPa) and baking (upper mold temperature 160°C, lower mold temperature 180°C).

[0158] Example 10

[0159] Preparation of the wax-based fluorine-free oil repellent

[0160] 70 g of 70# wax is dissolved at 85°C.

[0161] 9 g of modified starch and 81 g of water are gelatinized at 90°C and a rotation speed of 300 RPM / min, with a reaction time of 1 h.

[0162] 3 g of dispersant and 37 g of water are stirred and dissolved at a rotation speed of 500 RPM / min and a temperature of 85°C, under alkaline conditions with a pH of 8.5-9.5, with a stirring time of 2 h.

[0163] After the wax is completely dissolved, the dissolved modified starch and dispersant are added into the wax solution, respectively, at 85°C and a rotation speed of 500 RPM, with mixing and stirring for 15 min.

[0164] The temperature of the material is then raised to 90°C, and the high-pressure homogenizer is preheated with hot water. The emulsion is then passed through the high-pressure homogenizer while hot, at a pressure of 40 MPa.

[0165] The material after high pressure homogenization is naturally cooled to 35°C at a rotation speed of 500 RPM / min, thereby obtaining stable and small particle size wax-based fluorine-free oil repellent.

[0166] In this embodiment, the nitrogen content of the modified starch is 0.2-1%,

[0167] The dispersant is a styrene-maleic anhydride copolymer, a regular copolymer obtained by copolymerization of styrene and maleic anhydride, and the weight average molecular weight is 0.25-10,000.

[0168] Preparation of the paper pulp molded product:

[0169] The bagasse pulp board: bamboo pulp board = 6:4 is crushed and ground at a pulp concentration of 2%, and a pulp slurry with a degree of beating of 20-30°SR is obtained. The weight of the bagasse pulp board and the bamboo pulp board is 97% of the dry weight of the paper pulp molded product.

[0170] The white water in the circulating system is added to dilute the well-disintegrated pulp slurry to 0.8%, 2% alkyl ketene dimer (AKD) is first added under stirring at a stirring speed of 100-500 RPM / min, and then stirred for 5 min, 3% wax-based fluorine-free oil repellent is added, and stirred for 5 min. After wet embryo molding (vacuum degree -0.03-0.08 MPa) and baking (upper mold temperature 160°C, lower mold temperature 180°C), a paper pulp molded product with a water content of 8% is obtained.

[0171] Comparative Example 1

[0172] Preparation of the paper pulp molded product:

[0173] The bagasse pulp board: bamboo pulp board = 8:2 is crushed and ground at a pulp concentration of 2%, and a pulp slurry with a degree of beating of 20-30°SR is obtained. The white water in the circulating system is added to dilute the well-disintegrated pulp slurry to 0.3%-0.8%, 2% alkyl ketene dimer (AKD) is first added under stirring at a stirring speed of 100-500 RPM / min, and then stirred for 5 min, 5% of an oil repellent of a certain brand (appearance: brownish emulsion, solid content 34%, particle size 1-2 μm, PCD +0.00924 eq / Kg) is added, and stirred for 5 min. After wet embryo molding (vacuum degree -0.03-0.08 MPa) and baking (upper mold temperature 160°C, lower mold temperature 180°C), a paper pulp molded product with a water content of 8% is obtained.

[0174] Comparative Example 2

[0175] Preparation of the wax-based fluorine-free oil repellent:

[0176] The modified starch 8 g and water 72 g are pasted at 90°C and a rotation speed of 300 RPM / min, and the reaction time is 1 h.

[0177] The dispersant styrene-acrylic acid ester copolymer 5g, water 55g, rotation speed 500 RPM / min, temperature 85°C, basic condition PH 8.5-9.5, stirring and dissolving, stirring time 2h.

[0178] 60g of 70# wax is dissolved at 85°C.

[0179] After the wax is completely dissolved, the modified starch and the dispersant are added into the wax solution at 85°C and rotation speed 500 RPM, and mixed and stirred for 15 min. Then the material temperature is raised to 85°C, the high-pressure homogenizer is preheated with hot water, and the emulsion is passed through the high-pressure homogenizer while hot. The pressure is 40 Mpa. After high-pressure homogenization, the material is naturally cooled to 35°C at a rotation speed of 500 RPM / min, thereby obtaining a stable and small-particle-size wax-based fluorine-free oil-proof agent.

[0180] In this embodiment, the modified starch is corn starch with nitrogen content of 0.4%. The dispersant is a high-molecular-weight polymer copolymerized from styrene and acrylic acid ester monomers, with weight-average molecular weight of 10-100,000, particle size of 0.3-2 μm, and solid content of 30%-60%.

[0181] Preparation of paper pulp molded product:

[0182] The sugarcane pulp board and the bamboo pulp board are mixed in a weight ratio of 8:2, and are disintegrated and ground at a pulp concentration of 2 wt%, to obtain a pulp slurry with beating degree of 20-30°SR. The weight of the sugarcane pulp board and the bamboo pulp board is 99% of the dry weight of the paper pulp molded product.

[0183] The disintegrated pulp slurry is diluted to 0.5 wt% with white water in a circulating system, and 1 wt% of a cationic aluminum salt solution (cationic aluminum salt concentration is 50%) is added under stirring at a rotation speed of 100-500 RPM for 5 min. Then 2 wt% of alkyl alkene ketone dimer (AKD) is added and stirred for 5 min. Finally, 5 wt% of the wax-based fluorine-free oil-proof agent is added and stirred for 5 min. After wet blank forming (vacuum degree -0.03-0.08 Mpa) and baking (upper mold temperature 160°C, lower mold temperature 180°C), a paper pulp molded product with water content of 8% is obtained. In this embodiment, the cationic aluminum salt is Al2(OH)5Cl.

[0184] It should be noted that the above percentage is based on the dry weight of the paper pulp molded product as 100%.

[0185] Comparative Example 3

[0186] Preparation of wax-based fluorine-free oil-proof agent:

[0187] Modified starch 8g, water 72g, at 90℃, 300RPM / min, starch paste for 1h.

[0188] Dispersant polyvinyl alcohol 3g, water 57g, 500RPM / min, 85℃, PH 8.5-9.5, stirring and dissolving, stirring time 2h.

[0189] 60g of 70# wax is dissolved at 85℃.

[0190] After the wax is completely dissolved, the dissolved modified starch and dispersant are added into the wax solution at 85℃ and 500RPM, and mixed and stirred for 15min. Then the temperature is raised to 85℃, the high-pressure homogenizer is preheated with hot water, and the emulsion is passed through the high-pressure homogenizer at a pressure of 40Mpa. After high-pressure homogenization, the material is naturally cooled to 35℃ at a stirring speed of 500RPM / min, thereby obtaining a stable and small-particle-size wax-based fluorine-free oil repellent.

[0191] In this embodiment, the modified starch is corn starch with a nitrogen content of 0.4%. The dispersant is polyvinyl alcohol with a degree of polymerization of 1700-1800, an alcoholysis degree of 85%, and a molecular weight of 80,000.

[0192] Preparation of paper pulp molded products:

[0193] Sugarcane pulp board and bamboo pulp board are mixed in a weight ratio of 8:2, and are crushed and milled at a pulp concentration of 2wt%, to obtain a pulp slurry with a degree of beating of 20-30°SR.

[0194] The broken pulp slurry is diluted to 0.5wt% with white water in a circulating system, and 1wt% of a cationic aluminum salt solution (cationic aluminum salt concentration 50%) is added under stirring at a speed of 100-500RPM for 5min, followed by the addition of 2wt% of alkyl alkene ketone dimer (AKD) for 5min, and finally 5wt% of wax-based fluorine-free oil repellent for 5min. After wet embryo molding (vacuum degree -0.03-0.08Mpa) and baking (upper mold temperature 160℃, lower mold temperature 180℃), paper pulp molded products with a moisture content of 8% are obtained. In this embodiment, the cationic aluminum salt is Al2(OH)5Cl.

[0195] It should be noted that the above percentage is based on the dry weight of the paper pulp molded products.

[0196] Performance testing

[0197] According to GB / T 36787-2018 "Paper Pulp Molded Tableware" and customer requirements, the oil resistance test is carried out at 60-20℃.

[0198] Test items include:

[0199] 1. Oil resistance level evaluation of leakage of dinner plate

[0200] The test method is: hot oil at a specified temperature is poured into a round dinner plate, and the test is performed for 30 minutes, and then the hot oil is poured out. The inner and outer surfaces of the bottom of the dinner box are observed, and the oil resistance level is evaluated according to the leakage. Level 5 is no discoloration of the inner surface; Level 4 is a small amount of discoloration of the inner surface, and no leakage of the outer surface; Level 3 is a small amount of leakage of the outer surface; Level 2 is that the leakage area of the outer surface is less than 50%; Level 1 is that the leakage area of the outer surface is greater than 50%; and Level 0 is that the outer surface immediately leaks.

[0201] The test is further divided into a low-temperature attenuation test of the pulp molded product and a low-temperature oil resistance performance test of the pulp molded product after being taken out of the machine;

[0202] 2. Water resistance test

[0203] Hot water close to boiling at 95℃ is poured into the dinner plate, and the test is performed for 30 minutes, and then the hot water is poured out. Whether the dinner box leaks is observed.

[0204] The test results can be referred to Figure 1 and Figure 2 and Table 1;

[0205] Table 1 test results

[0206]

[0207]

[0208] According to Table 1 and Figure 1 , Figure 2 the following conclusions can be drawn:

[0209] 1. As can be seen from Examples 1 to 10, by using the method of the present application, the low-temperature oil resistance level can generally reach Level 4;

[0210] 2. As can be seen from Examples 1 to 10, only Examples 1 to 3 reached Level 4 in the 20℃ oil resistance level after 60 days;

[0211] Among them, the high-temperature oil resistance level of Example 5 is poor, and the possible reason is that the amount of wax, the amount of dispersing agent, and the amount of modified starch in the oil repellent emulsion are all large, so that the solid content of the emulsion is high, the emulsification effect is reduced, and the final high-temperature oil resistance performance is poor;

[0212] It can be seen from the comparison of Example 1 to Example 3, Example 4 and Example 5 that the proportion of each auxiliary in the oil repellent is controlled properly, which can significantly improve the oil repellency grade after storage;

[0213] It can be seen from the comparison of Example 1 to Example 3, Example 6 and Example 7 that using paraffin wax as the wax in the oil repellent can significantly improve the oil repellency grade after storage;

[0214] It can be seen from the comparison of Example 1 to Example 3, Comparative Example 8 to Comparative Example 10 that using a cationic aluminum salt can effectively improve the oil repellency grade after storage;

[0215] 3. It can be seen from Comparative Example 1 and the examples that the performance advantage of the present application compared with the commercially available product is the oil repellency performance after storage;

[0216] It can be seen from Comparative Example 2 and 3 and the examples that in the present application, selecting styrene-maleic anhydride copolymer as the dispersant is an effective guarantee for improving the performance, especially the low-temperature oil repellency performance.

[0217] It is apparent to those skilled in the art that the present application is not limited to the details of the foregoing exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all respects as illustrative and not restrictive, and the scope of the present application should be defined by the appended claims rather than the above description, and it is intended that all changes that come within the meaning and range of equivalents of the claims are embraced therein. Any reference signs in the claims should not be construed as limiting the claims to the figures in which the reference signs are used.

Claims

1. A composition for processing molded pulp articles, characterized in that, Including fluorine-free oil repellents, cationic aluminum salts, and alkyl ketene dimers; The weight ratio of the fluorine-free oil repellent, cationic aluminum salt, and alkyl ketene dimer is 3~5:0.25~1:1.9~2.8; The cationic aluminum salt is a polymer of water-soluble inorganic trivalent aluminum salt; The cationic aluminum salt has the following general formula: Al2(OH) x Cl y ; x = 2~5; y = 1~4 The fluorine-free oil repellent is an emulsion composed of wax, cationic starch, dispersant, and water; the dispersant is a styrene-maleic anhydride copolymer. The wax content is 25-40 wt%; The cationic starch content is 1~4.5 wt%; The content of the dispersant is 0.5~7wt%; The cationic starch has tertiary amino or quaternary ammonium groups, and the nitrogen content of the cationic starch is between 0.2 and 1 wt%.

2. The composition according to claim 1, characterized in that, The wax content is 30-35 wt%; The cationic starch content is 3~4.5 wt%; The content of the dispersant is 1~2wt%.

3. The composition according to claim 1, characterized in that, The wax is at least one of microcrystalline wax, Fischer-Tropsch wax, polyethylene wax, polypropylene wax, and paraffin wax.

4. The composition according to claim 3, characterized in that, The paraffin wax is one or more of paraffin waxes No. 52, 54, 56, 58, 60, 62, 64, 66, 68 and 70; the styrene-maleic anhydride copolymer is a regular copolymer obtained by block copolymerization of styrene and maleic anhydride, with a molecular weight of 0.2 to 20,000.

5. The composition according to claim 1, characterized in that, The preparation method of the fluorine-free oil repellent is as follows: gelatinized cationic starch, dispersant, water, and molten wax are mixed and homogenized to form an emulsion; The homogenization temperature is 85~90℃, the homogenization pressure is 20~40Mpa, and the temperature is allowed to cool naturally after the homogenization operation is completed.

6. A method for preparing pulp molded articles using the composition as described in claim 1 or 5, characterized in that, Includes the following steps: Step 1: Dilute the pulp with a freeness of 20~30°SR to a pulp concentration of 0.3~0.8wt%; Step 2: First add cationic aluminum salt to the slurry obtained in Step 1, then add alkyl ketene dimer, and finally add the fluorine-free oil repellent, and stir to mix. Step 3: Inject the slurry obtained in Step 2 into the mold, dehydrate it, and obtain a wet blank with a moisture content of 50~76wt%; Step 4: Dry and shape the wet preform to obtain the pulp molded product.

7. A pulp molded product, characterized in that, It was prepared using the method described in claim 6.

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