A degradable and recyclable bio-based emulsion and its preparation method and application

Abstract

The present application relates to the field of bio-based materials, and more specifically, it relates to a bio-based emulsion that is degradable and recyclable, and a preparation method and application thereof. Step 1: Shear a polyester bio-based material to obtain bio-based particles; Step 2: Emulsify a surfactant, an emulsifier, an anti-settling stabilizer, and bio-based particles in a solvent that does not dissolve the bio-based particles, remove the solvent that does not dissolve the bio-based particles, and obtain an emulsified bio-based composite; then weigh a diluent and mix the emulsified bio-based composite evenly to form a bio-based emulsion. The bio-based emulsion obtained above can be applied to the surface of paper. After curing, the formed coating has better oil-proof, heat-insulating, barrier and other properties, and has the characteristics of pulping recovery and degradability. The bio-based emulsion still maintains better stability after long-term storage, and ensures the stability and quality of the coating.

Description

Technical Field

[0001] The present application relates to the field of bio-based materials, and more specifically, to a biodegradable and recyclable bio-based emulsion and a preparation method and application thereof. Background Art

[0002] Coated PE means that PE plastic is crushed into particles, melted at 200°C, and then coated on the surface of paper and other substrates to form a protective film on the surface of paper and other substrates. It has better oil-proof, waterproof, moisture-proof and anti-corrosion effects, so it is widely used in pharmaceutical packaging, food packaging, home and construction industries.

[0003] However, coated PE is difficult to degrade in the natural environment, which affects the environment. After it is recycled, it is also difficult to pulp and recycle it. Therefore, there is currently a method of coating with PBS biodegradable materials, which can achieve rapid degradation and recycling in the natural environment. However, when coating uneven surfaces or coating thicker surfaces, the thickness is difficult to control accurately, and the coating equipment has high requirements and requires strict technical control, resulting in high costs.

[0004] Based on the above problems, EAA emulsion is applied to the surface of paper and other substrates by coating. After curing, a stable and uniform protective film is formed. The coating equipment is simpler than the laminating equipment and can be mass-produced. The coating thickness can be controlled as required, which is easier to control than laminating. Therefore, the production cost of the coating method is relatively low. Although EAA can be recycled by pulping, the raw materials of EAA are mainly derived from petroleum. Therefore, after being discarded, EAA is difficult to degrade quickly in the natural environment. Therefore, further research is needed. Summary of the invention

[0005] In order to make substrates such as paper biodegradable and recyclable after coating, and to be able to coat them by coating, while ensuring the stability and quality of the coating, the present application provides a biodegradable and recyclable bio-based emulsion, and a preparation method and application thereof.

[0006] In a first aspect, the present application provides a method for preparing a biodegradable and recyclable bio-based emulsion, comprising the following steps:

[0007] Step 1: shearing the polyester bio-based material to obtain bio-based particles;

[0008] Step 2: After emulsifying the surfactant, emulsifier, anti-settling stabilizer and bio-based particles in a solvent that does not dissolve the bio-based particles, the solvent that does not dissolve the bio-based particles is removed to obtain an emulsified bio-based composite; then a diluent is weighed and mixed evenly with the emulsified bio-based composite to form a bio-based emulsion.

[0009] In the above process, polyester bio-based material is a fully degradable material that can be rapidly degraded in the natural environment and has the characteristics of oil resistance, heat resistance, and barrier properties. The bio-based material is sheared to form powdered bio-based particles, which is conducive to its uniform dispersion in the emulsion.

[0010] While surfactants play a role in promoting the dispersion of bio-based particles, emulsifiers can play a role in emulsification and promoting dispersion, while anti-sedimentation stabilizers can ensure the stability of bio-based particles and reduce the occurrence of stratification, sedimentation and other phenomena.

[0011] When surfactants, emulsifiers, and anti-settling stabilizers are compounded, they play a synergistic role, thereby enabling the bio-based particles to be evenly dispersed in the bio-based emulsion and maintain better stability.

[0012] Therefore, the bio-based emulsion can be applied to the surface of paper and other substrates through coating, and after curing, a stable coating is formed, which makes the surface of paper and other substrates have better oil-proof, heat-resistant, barrier and other characteristics, and can be applied on uneven surfaces to form a coating with uniform thickness.

[0013] Furthermore, after the bio-based emulsion is coated on the surface of paper, the coated paper formed can be pulped and recycled, and can also be quickly degraded in the natural environment after being discarded, so it has the characteristics of recyclability and degradability.

[0014] The above process is to further improve the stability of the bio-based emulsion, improve its convenience in transportation and storage, and ensure that it still maintains good stability under long-term storage. The present application disperses the bio-based particles in a solvent that does not dissolve the bio-based particles, and emulsifies and disperses them evenly with the assistance of a surfactant, an emulsifier, and an anti-settling stabilizer, and then removes the solvent that does not dissolve the bio-based particles to form a colloidal bio-based composite. The emulsified bio-based composite has better convenience and stability during packaging, storage and transportation, and reduces the possibility of sedimentation.

[0015] When used, a diluent can be added to dilute it to form a bio-based emulsion with better stability. Therefore, when used to coat the surface of a substrate such as paper, the stability and quality of the formed coating can be guaranteed.

[0016] The emulsified bio-based composite and diluent of the present application are equivalent to component A and component B. During use, the two components only need to be simply mixed evenly to obtain a bio-based emulsion, which is convenient for coating and ensures the stability of the bio-based emulsion, thereby ensuring the stability and quality of the formed coating.

[0017] If the bio-based emulsion shows unstable phenomena such as sedimentation during use, it will cause the dry weight of the coating to be different after coating, thus affecting the uniformity and stability of each batch of coating, which is not conducive to quality assurance of the mass production process.

[0018] In summary, the present application makes it easy to disperse and emulsify bio-based particles in the emulsion through the interaction of surfactants, emulsifiers, and anti-settling stabilizers, and avoids the sedimentation and stratification of bio-based particles during the use of the bio-based emulsion, thereby improving the stability of the bio-based emulsion.

[0019] The bio-based emulsion of the present application can be coated on the surface of a substrate such as paper by coating. After curing, the formed coating has better oil-proof, heat-insulating, and barrier effects, so it can replace PBS or PE coating in food packaging and other fields. It can also be pulped and recycled, and can be quickly degraded after being discarded.

[0020] In addition, the bio-based emulsion has better stability. After being placed for a long time, it can maintain better stability and ensure the stability and quality of the coating. Therefore, when the bio-based emulsion of this application is used in food packaging and other production, it is not only biodegradable, recyclable, oil-proof, and has low production costs, but also the bio-based emulsion has better stability, which can ensure the stability and uniformity of each batch of coating and obtain better quality.

[0021] Preferably, the specific steps in step 2 are as follows:

[0022] The surfactant, the emulsifier, the anti-settling stabilizer and the first solvent in which the bio-based particles are not dissolved are mixed evenly to obtain a dispersion A; the bio-based particles are weighed and mixed with the second solvent in which the bio-based particles are not dissolved to obtain a mixed solution B; the dispersion A and the dispersion B are mixed evenly, emulsified, and the first solvent and the second solvent in which the bio-based particles are not dissolved are removed to obtain an emulsified bio-based composite; the diluent and the emulsified bio-based composite are mixed evenly to form a bio-based emulsion.

[0023] By forming dispersion A and mixed solution B, the raw material system is mixed evenly to form a stable emulsion. The emulsified bio-based composite obtained by removing the solvent has good stability and can be stored for a long time. When used, it can be quickly dispersed in the diluent to form a uniformly dispersed bio-based emulsion. When the bio-based emulsion is applied to the surface of paper, a coating with uniform thickness is formed.

[0024] Preferably, the polyester bio-based material is composed of one or more of PBS, PLA, and PHA.

[0025] Among the above raw materials, PBS, PLA, and PHA are all fully degradable bio-based materials, which can be rapidly degraded in the natural environment and are oil-resistant. The bio-based particles formed by them are dispersed and emulsified with the assistance of surfactants, emulsifiers, anti-settling stabilizers, and diluents to form a bio-based emulsion containing bio-based particles.

[0026] Among them, PBS has good heat resistance, and its heat deformation temperature can exceed 100°C. PLA has higher strength and stiffness, good tensile strength and ductility, but relatively poor heat resistance. PHA: It has a balance of rigidity and toughness, good barrier properties, but unstable thermoplasticity and hot processing temperature. When two or three of PBS, PLA, and PHA are combined, they can achieve better comprehensive performance, so that they can be applied to bio-based emulsions. With the cooperation of surfactants, emulsifiers, and anti-settling stabilizers, they can be evenly dispersed, and the emulsion formed is stable. It can be coated on the surface of substrates such as paper by coating, forming a coating with stable quality, and during use, it has better oil resistance.

[0027] Since PLA is easily hydrolyzed in water for a long time after forming particles, when PBS, PLA and PHA are compounded to form bio-based particles, the emulsified bio-based composite formed through emulsification and other processes is easier to store, and can be directly used for coating after being dispersed with a diluent. When the production line mixes the emulsified bio-based composite and the diluent, the mixing and coating are synchronized. Therefore, the bio-based emulsion obtained after uniform mixing is quickly transferred to the coating equipment for coating. The process time is short, and during this time, even if the diluent used is water, the PLA will not be completely hydrolyzed.

[0028] Preferably, the particle size of the bio-based particles is 1-2 μm. The bio-based particles in the above particle size range are easy to be emulsified and suspended, and the formed bio-based emulsion is easy to protect the film.

[0029] Preferably, the surfactant is one or more of sodium cocoyl methyl taurate, sodium lauroyl glutamate, and dodecyl dimethyl betaine.

[0030] Sodium cocoyl methyl taurate, sodium lauroyl glutamate, and dodecyl dimethyl betaine can improve the dispersibility of bio-based particles and make them easier to coat on the surface of the substrate to form a stable protective layer. They also interact with emulsifiers and anti-settling stabilizers to reduce the possibility of sedimentation and maintain the stability of the emulsion state.

[0031] Preferably, the emulsifier is polyglyceryl-3 polyricinoleate and / or lauryl glucoside.

[0032] Polyglycerol-3 polyricinoleate or lauryl glucoside both play an emulsifying role and have good dispersibility. Therefore, they interact with surfactants and anti-settling stabilizers, so that the bio-based emulsion can obtain better stabilizers during use and reduce the occurrence of sedimentation and other phenomena.

[0033] Preferably, the anti-settling stabilizer is composed of the following weight percentages:

[0034] Bis(2,6-diisopropylbenzene)carbodiimide 0-5%

[0035] Anti-settling compounds 30-50%

[0036] Chitosan citrate 10-30%

[0037] Hydrogenated starch hydrolysate 10-30%

[0038] Mussel mucin 3-10%

[0039] The balance is sodium hydroxymethylcellulose.

[0040] Anti-settling compounds have anti-settling and thixotropic effects; sodium hydroxymethyl cellulose has better thickening, emulsifying, stabilizing and suspending effects. Chitosan citrate is a polymer salt generated by the reaction of chitosan and citric acid. It has the properties of both and has better emulsification stability, thickening, pH adjustment and permeability, so that the formed emulsion has better emulsification stability and is easy to apply.

[0041] Mussel mucin has adhesion, thickening, environmental protection and non-toxicity; hydrogenated starch hydrolysate forms a microemulsion after dissolution, has certain adhesion, plays a thickening role, and is thermally stable, can maintain good stability, and can interact with mussel mucin and sodium hydroxymethyl cellulose, and cooperate with anti-settling compounds and chitosan citrate to make the obtained bio-based emulsion have good stability, anti-settling and easy coating properties. After long-term storage, it still maintains good stability. After coating, the formed coating has stable quality.

[0042] In addition, the present application uses bis(2,6-diisopropylbenzene) carbodiimide as an anti-hydrolysis agent, which can reduce the possibility of PLA hydrolysis and also enhance the water resistance, heat resistance and oxidation resistance of the material. Combined with the anti-settling compound, chitosan citrate, hydrogenated starch hydrolysate, mussel mucin, and sodium hydroxymethylcellulose to form an anti-settling stabilizer, the bio-based particles have better dispersion stability, film-forming stability and anti-settling properties to ensure the stability of the bio-based emulsion.

[0043] The preferred manufacturer of hydrogenated starch hydrolysate is Wuhan Huaxiang Kejie Biotechnology Co., Ltd., with an active ingredient content of 99%.

[0044] Preferably, the anti-settling compound is water-based polyamide wax and / or polyamide-modified hydrogenated castor oil.

[0045] The use of water-based polyamide wax or polyamide-modified hydrogenated castor oil can play a thixotropic and anti-sedimentation role, and the anti-sedimentation stabilizer formed by chitosan citrate, hydrogenated starch hydrolysate, mussel mucin, and sodium hydroxymethyl cellulose has better stability and anti-sedimentation properties, and then interacts with surfactants and emulsifiers to reduce the sedimentation of bio-based emulsions. After long-term storage, it still has better stability and reduces the possibility of sedimentation.

[0046] In a second aspect, the present application provides a biodegradable and recyclable bio-based emulsion obtained by a method for preparing a biodegradable and recyclable bio-based emulsion, wherein the bio-based emulsion is composed of 50-80% by weight of a diluent and 20-50% by weight of a bio-based composite; the bio-based composite is composed of the following raw materials in percentage by weight:

[0047] Surfactant 1-5%

[0048] Emulsifier 1-3%

[0049] Anti-settling stabilizer 3-5%

[0050] The balance is bio-based pellets.

[0051] By using the above dosage ratio, the obtained bio-based emulsion has good stability, is easy to apply, and forms a stable coating. It can be used for oil-proof food packaging paper, etc., and is easily degraded after being discarded, and can be recycled by recycling, thereby improving its environmental friendliness.

[0052] On the third aspect, the present application improves the application of a degradable and recyclable bio-based emulsion, the degradable and recyclable bio-based emulsion is coated on the surface of paper, dried, and a degradable coating is formed on the surface of the paper to obtain a degradable and recyclable coated paper, and the degradable and recyclable coated paper is applied to food packaging.

[0053] Degradable and recyclable coated paper can be used in sandwich wrapping paper, dinner plate tray paper, grease-proof paper, vacuum packaging bags, and packaging paper bags such as Codonopsis pilosula and Astragalus membranaceus to play a sealing role. When used in oil-proof food packaging paper, it can be used for packaging hamburgers, bread, etc., and can also be used for laying on pallets as grease-proof paper, etc.; when used in oil-proof food packaging bags, it can be used to hold street snacks, can replace plastic bags, and play a role in environmental protection and health.

[0054] When used in food packaging, it has a better oil-proof effect and provides practicality.

[0055] In summary, this application has the following beneficial effects:

[0056] 1. This application uses the interaction of surfactants, emulsifiers, and anti-settling stabilizers to make bio-based particles easily dispersed and emulsified in the emulsion, reduce the sedimentation and stratification of bio-based particles, and improve the stability of the bio-based emulsion. The bio-based emulsion can be applied to the surface of paper by coating. After curing, the formed coating has better oil-proof, heat-insulating, and barrier properties, and can be pulped and recycled. It can also be quickly degraded after being discarded. The formed bio-based emulsion still maintains better stability after long-term storage, so as to ensure the stability and uniformity of each batch of coatings and improve its quality.

[0057] 2. The present application uses the interaction of mussel mucin, hydrogenated starch hydrolysate, sodium hydroxymethylcellulose, anti-settling compounds, and chitosan citrate, and then uses surfactants and emulsifiers to make the obtained bio-based emulsion have better stability, anti-settling properties, and easy coating properties. After long-term storage, it still maintains better stability, reduces the occurrence of sedimentation and stratification, and after coating, the quality of the formed coating is stable. And the paper formed with the coating is used in food packaging paper, which has a better oil-proof effect. DETAILED DESCRIPTION

[0058] The present application is further described in detail below with reference to the embodiments.

[0059] Some raw materials introduction:

[0060]

[0061]

[0062] Example

[0063] Example 1

[0064] A method for preparing a biodegradable and recyclable bio-based emulsion comprises the following steps:

[0065] Step 1: Put the polyester bio-based material into a shearing machine for shearing to obtain bio-based particles with a particle size of 2 μm; Step 2: Weigh 0.5 kg of surfactant, 0.5 kg of emulsifier, 1 kg of anti-settling stabilizer, 8 kg of bio-based particles, and 5 kg of 75% ethanol by mass and mix them evenly to obtain a bio-based composite; heat the obtained bio-based composite to 60°C, emulsify it at a speed of 150 r / min for 10 minutes, and then perform reduced pressure distillation to remove water and anhydrous ethanol. The pressure gauge shows 0.08 MPa to obtain an emulsified bio-based composite; weigh 10 kg of diluent and 10 kg of emulsified bio-based composite at a speed of 150 r / min, mix them for 2 minutes, and the mixing temperature is room temperature (25°C) to make it in an emulsion state to obtain a bio-based emulsion.

[0066] According to weight percentage, the anti-settling stabilizer is obtained by mixing 50% of anti-settling compound, 30% of chitosan citrate, 10% of hydrogenated starch hydrolysate, 3% of mussel mucin and 7% of sodium hydroxymethylcellulose.

[0067] The surfactant is dodecyl dimethyl betaine, the emulsifier is polyglycerol-3 polyricinoleate, the diluent is a 50% alcohol solution by mass, the anti-settling compound is water-based polyamide wax, and the bio-based material is obtained by mixing PBS and PHA in a weight ratio of 1:1.

[0068] Example 2

[0069] The difference between Example 2 and Example 1 is that the specific steps in step 2 are as follows:

[0070] Step 2: Weigh 0.5 kg of surfactant, 0.5 kg of emulsifier, 1 kg of anti-settling stabilizer and mix them evenly with 5 kg of water to obtain dispersion A; weigh 8 kg of bio-based particles and mix them with 5 kg of anhydrous ethanol to obtain a mixed solution B; then add all of the dispersion A to the mixed solution B, mix evenly, heat to 60°C, and emulsify for 30 minutes at a speed of 150 r / min, and then perform reduced pressure distillation to remove water and anhydrous ethanol. The pressure gauge shows 0.08 MPa to obtain an emulsified bio-based composite; weigh 10 kg of diluent and 10 kg of emulsified bio-based composite at a speed of 150 r / min, mix for 2 minutes, and the mixing temperature is room temperature (25°C) to make it in an emulsion state to obtain a bio-based emulsion.

[0071] Example 3

[0072] The difference between Example 3 and Example 2 is that the bio-based particles are 1 μm; the emulsifier is obtained by mixing polyglycerol-3 polyricinoleate and lauryl glucoside in a weight ratio of 1:1; and the bio-based material is obtained by mixing PBS and PHA in a weight ratio of 1:1.

[0073] Example 4

[0074] The difference between Example 4 and Example 3 is that the dosage composition of the anti-settling stabilizer is different, as follows:

[0075] According to weight percentage, the anti-settling stabilizer is obtained by mixing 5% of bis(2,6-diisopropylbenzene)carbodiimide, 50% of anti-settling compound, 30% of chitosan citrate, 10% of hydrogenated starch hydrolysate, 3% of mussel mucin and 2% of sodium hydroxymethylcellulose.

[0076] Example 5

[0077] The difference between Example 5 and Example 4 is that the bio-based material is obtained by mixing PBS, PHA, and PLA in a weight ratio of 5:2:3, and the rest is the same as Example 4.

[0078] Example 6

[0079] The difference between Example 6 and Example 3 is: 0.2 kg surfactant, 1 kg emulsifier, 0.8 kg anti-settling stabilizer, and 9 kg bio-based particles.

[0080] Example 7

[0081] The difference between Example 7 and Example 3 is that the surfactant is composed of sodium cocoyl methyl taurate, sodium lauroyl glutamate, and dodecyl dimethyl betaine in a weight ratio of 1:1:1.

[0082] Example 8

[0083] The difference between Example 8 and Example 3 is that, based on weight percentage, the anti-settling stabilizer is obtained by mixing 1% bis(2,6-diisopropylbenzene)carbodiimide, 40% anti-settling compound, 20% chitosan citrate, 30% hydrogenated starch hydrolysate, 6% mussel mucin, and 3% sodium hydroxymethylcellulose.

[0084] Example 9

[0085] The difference between Example 9 and Example 3 is that, based on weight percentage, the anti-settling stabilizer is obtained by mixing 30% of an anti-settling compound, 30% of chitosan citrate, 30% of hydrogenated starch hydrolysate, 8% of mussel mucin, and 2% of sodium hydroxymethylcellulose.

[0086] Example 10

[0087] The difference between Example 10 and Example 8 is that the anti-settling compound is composed of water-based polyamide wax and polyamide-modified hydrogenated castor oil in a weight ratio of 1:2.

[0088] Embodiment 11

[0089] The difference between Example 11 and Example 3 is that an equal amount of chitosan citrate is replaced by hydrogenated starch hydrolysate.

[0090] Example 12

[0091] The difference between Example 12 and Example 3 is that an equal amount of hydrogenated starch hydrolysate is replaced by chitosan citrate.

[0092] Example 13

[0093] The difference between Example 13 and Example 3 is that an equal amount of mussel mucin is replaced by an anti-settling compound.

[0094] Embodiment 14

[0095] The difference between Example 14 and Example 3 is that an equal amount of sodium hydroxymethyl cellulose is replaced by an anti-settling compound.

[0096] Embodiment 15

[0097] The difference between Example 15 and Example 3 is that the anti-settling compound is water-based polyamide wax.

[0098] Comparative Example

[0099] Comparative Example 1

[0100] The difference between Comparative Example 1 and Example 3 is that the anti-settling stabilizer is replaced by an emulsifier in equal amounts.

[0101] Comparative Example 2

[0102] The difference between Comparative Example 2 and Example 5 is that step 2 is different, as follows:

[0103] Weigh 0.5 kg of surfactant, 0.5 kg of emulsifier, 1 kg of anti-settling stabilizer, 8 kg of bio-based particles, and 10 kg of diluent into a stirring device, mix them thoroughly at a speed of 150 r / min, heat to 60° C., and emulsify for 30 minutes to make them into an emulsion state, thereby obtaining a bio-based emulsion.

[0104] Application Examples

[0105] Application Example 1

[0106] Application of a biodegradable and recyclable bio-based emulsion: the emulsified bio-based emulsion obtained in Example 1 is applied to paper (paper specification 120g / m 2 ) on both sides, with a wet coating weight of 18g / m 2 After coating, the paper is dried at 178°C for 1 second, then at 120°C for 5 seconds, at 80°C for 1 minute, and finally at 60°C for 5 minutes, cooled to 30°C, and a degradable coating is formed on both sides of the paper to obtain a degradable and recyclable coated paper; the degradable and recyclable coated paper is then used in food packaging paper.

[0107] Application Example 2-17

[0108] The difference between Application Example 2-17 and Application Example 1 is that the source of the bio-based emulsion is different, as shown in Table 2;

[0109] Table 2 Sources of bio-based emulsions in application examples 1-17

[0110]

[0111]

[0112] Application comparison

[0113] Application Comparative Example 1

[0114] The difference between Application Comparative Example 1 and Application Example 1 is that the bio-based emulsion is an EVA emulsion with a solid content of 50%.

[0115] Performance testing

[0116] Detection method / test method

[0117] 1. Stability

[0118] 1) Take 1 L of the bio-based emulsion obtained in Examples 1-15 and Comparative Examples 1-2 and put it into a graduated cylinder. After sealing and placing it for 3 months, the ambient temperature is 40°C and the ambient humidity is 60%. Observe whether sedimentation occurs. If no sedimentation or stratification is observed, it is recorded as no sedimentation. If sedimentation or stratification is observed, check the liquid level of stratification or sedimentation. If the liquid level of stratification or sedimentation is below 50ML, it is recorded as a small amount of sedimentation. If the liquid level of stratification or sedimentation is above 50ML, it is recorded as a large amount of sedimentation.

[0119] 2) After the emulsified bio-based composites obtained in Examples 1-15 and Comparative Example 1 were sealed and placed for 6 months, the ambient temperature was 50°C and the humidity was 65%, and then they were mixed with a 50% alcohol solution by weight ratio of 1:1, and stirred at a speed of 150r / min for 2min. The mixing temperature was room temperature (25°C) to make it in an emulsion state, and 10kg of the bio-based emulsion was obtained after being placed, and then placed in a 10L measuring cylinder, and then sealed and placed for 7 days, and the upper 1 / 3 liquid surface was taken to obtain the emulsified bio-based emulsion, which was applied to paper (paper specification 120g / m 2 ) on both sides, with a wet coating weight of 18g / m 2 After coating, it is dried at 178°C for 1s, then dried at 120°C for 5s, dried at 80°C for 1min, and finally dried at 60°C for 5min, cooled to 30°C, and a degradable coating is formed on both sides of the paper to obtain a degradable and recyclable coated paper. The weight of the recycled paper is measured and recorded as g1, and the weight of the degradable and recyclable coated paper of Application Example 1-17 is weighed and recorded as g2.

[0120] 3) After the bio-based emulsion obtained in Comparative Example 2 was sealed and placed for 6 months, the ambient temperature was 50°C, the humidity was 65%, and the rotation speed was 150r / min, and it was stirred for 2 minutes. The mixing temperature was room temperature (25°C) to make it in an emulsion state. 10 kg was taken and put into a 10L measuring cylinder. After being sealed and placed for 7 days, the upper 1 / 3 liquid surface was taken, and the emulsified bio-based emulsion was coated on paper (paper specification 120g / m 2) on both sides, with a wet coating weight of 18g / m 2 After coating, the paper was dried at 178°C for 1 second, then at 120°C for 5 seconds, at 80°C for 1 minute, and finally at 60°C for 5 minutes. The paper was cooled to 30°C to form a degradable coating on both sides of the paper to obtain a degradable and recyclable coated paper, and its weight was measured and recorded as g3.

[0121] The mass loss rate of application example 1-17 is equal to 1-(g1 / g2)100%; the mass loss of comparative example 2 is equal to 1-(g3 / g2)100%. The higher the mass loss rate, the easier it is to settle and the worse its stability.

[0122] Table 3 Experimental data of Examples 1-15 and Comparative Examples 1-2

[0123]

[0124] Combining Example 3 and Comparative Example 1 and Table 3, it can be seen that Example 1 did not have any sedimentation phenomenon, and the mass loss rate was lower than that of Comparative Example 1, indicating that the bio-based emulsion prepared by the process of the present application has better stability, reduces the occurrence of stratification, sedimentation and the like, and improves the quality after coating.

[0125] Combining Example 5 and Comparative Example 2 with Table 3, it can be seen that the mass loss rate of Example 3 is lower than that of Comparative Example 2, indicating that the bio-based emulsion obtained by the preparation process of the present application has better stability.

[0126] Combining Example 3 and Examples 11-15 and Table 3, it can be seen that Example 3 did not show sedimentation, and the mass loss rate was lower than that of Examples 11-15, indicating that the anti-sedimentation compound, chitosan citrate, hydrogenated starch hydrolysate, mussel mucin, and sodium hydroxymethyl cellulose interact with each other to obtain better anti-sedimentation and stability.

[0127] 2. Degradation rate

[0128] According to the national standard GB / T20197-2006, a degradation test was carried out. After the degradable and recyclable coated paper obtained in Application Example 1, Application Example 4, Application Example 5, Application Example 9, Application Example 15, and Application Comparative Example 1 was buried in the soil for 100 days, the degradation rate was calculated.

[0129] 1. Prevent oil leakage

[0130] The degradable and recyclable coated paper obtained in Application Example 3, Application Example 5, Application Example 10, Application Example 16 and Application Comparative Example 1 was cut and laid in a 100 mL culture dish so that it completely covered the bottom and the inside of the culture dish, and then 50 g of pure peanut oil at a temperature of 50°C was poured in. The room temperature was maintained at 30°C and the humidity was 68%. After leaving it for 3 hours, the degradable and recyclable coated paper and pure peanut oil were taken out, and the culture dish was filled with clean water to observe whether there was oil stain. If there was oil stain, it was marked as unqualified, and if there was no oil stain, it was marked as qualified.

[0131] 2. Burst resistance

[0132] The degradable and recyclable coated paper obtained in Application Example 3, Application Example 5, Application Example 10, Application Example 16 and Application Comparative Example 1 was tested for bursting resistance with reference to ISO2758 standard.

[0133] The above experimental structure is shown in Table 4;

[0134] Table 4 Experimental data of application example 3, application example 5, application example 10, application example 16, and comparative application example 1

[0135] Test items Degradation rate (%) Oil leakage prevention Burst strength Kpa Application Example 3 99 qualified 275 Application Example 5 99 qualified 287 Application Example 10 99 qualified 277 Application Example 16 99 Failure 195 Application Comparative Example 1 93 qualified 307

[0136] As can be seen from Table 4, the oil leakage prevention of Application Example 3, Application Example 5, and Application Example 10 are all qualified, with degradation rates of 99% and bursting resistance above 270Kpa; while the oil leakage prevention of Application Example 16 is unqualified, and the bursting resistance is less than 200Kpa; the degradation rate of Application Comparative Example 1 is 93%, and the bursting resistance is not much different from that of Application Example 5, indicating that the biodegradable and recyclable coated paper formed after coating with the bio-based emulsion of the present application has high degradation efficiency, oil-proof effect and bursting resistance.

[0137] 3. Recyclable

[0138] The rating standard of "Assessment of Recyclability of Packaging Products-Recyclability Score" has four evaluation indicators, namely coarse slag rate, flake content, sticky area and optical uniformity, and the highest score of the four indicators is (MSp).

[0139] The degradable and recyclable coated paper obtained from Application Example 4, Application Example 5, Application Example 10 and Application Comparative Example 1 was subjected to a recyclable repulping test, and the specific steps are as follows: the degradable and recyclable coated paper was placed in an oven at 50°C, dried for 10 minutes, 480g was weighed, and cut into a size of 100mm*100mm, and then placed in a stirring barrel, and 50°C water was added to a slurry concentration of 4%. After soaking for 30 minutes, a pulper was used to pulp at a rotation speed of 3000rpm for 5 minutes to obtain slurry; and the slurry was then subjected to a coarse residue rate test, an ash content test, an adhesive area test, and a flake content test.

[0140] Among them, the maximum scores for coarse slag rate, ash content, stickies area, and flake content are 35, 15, 40, and 10, and the total score is 100.

[0141] The maximum limits (THp) of the coarse slag rate, flake content and adhesive area are 30%, 40% and 30000mm respectively. 2 / kg.

[0142] The optical uniformity of the hand-copied sheets was visually inspected and compared with the reference samples to give a score, which was divided into three levels: excellent (no visible unevenness), with a score of 10 points; good (obvious visible unevenness), with a score of 5 points; and pass (large amounts of visible unevenness), with a score of 0 points.

[0143] Warning value range of coarse slag rate: high value (WR high ): 30%; low value (WR loe ): 20%;

[0144] Warning value range of adhesive area: high value (WR high ): 30000mm 2 / kg; low value (WR loe ): 20000mm2 / kg; in other cases, the score is calculated according to the following method:

[0145] (When 0<Rp<WR low )

[0146] (When WR high <Rp<100)

[0147] When WRloe<Rp<WRhigh, the recyclability is 0;

[0148] In the calculation formula, P refers to the three indicators of coarse slag rate, flake content and adhesive area;

[0149] PSp—index score; TSp—index target value; RSp—index test value;

[0150] WR loe —Warning low value; WR high —Warning about high values; MSp — the highest score of the indicator.

[0151] When the total score is 71-100, the recyclability is good, while the total score of 70 and below indicates poor recyclability.

[0152] Recyclability score see Table 5

[0153]

[0154]

[0155] As can be seen from the above table, the total scores of the degradable and recyclable coated papers prepared in the present application are all 100 points, while the total score of the EVA emulsion used in comparative example 1 is 95 points, indicating that the bio-based emulsion of the present application has better recyclability.

[0156] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for preparing a biodegradable and recyclable bio-based emulsion, characterized in that: The following steps are involved: Step 1: shearing the polyester bio-based material to obtain bio-based particles; Step 2: After emulsifying the surfactant, emulsifier, anti-settling stabilizer and bio-based particles in a solvent that does not dissolve the bio-based particles, the solvent that does not dissolve the bio-based particles is removed to obtain an emulsified bio-based composite; and then weighing a diluent and mixing the emulsified bio-based composite evenly to form a bio-based emulsion; The polyester bio-based material is composed of one or more of PBS, PLA, and PHA; The surfactant is one or more of sodium cocoyl methyl taurate, sodium lauroyl glutamate, and dodecyl dimethyl betaine; The emulsifier is polyglyceryl-3 polyricinoleate and / or lauryl glucoside; The anti-settling stabilizer is composed of the following weight percentages: Bis(2,6-diisopropylbenzene)carbodiimide 0-5% Anti-settling compounds 30-50% Chitosan citrate 10-30% Hydrogenated starch hydrolysate 10-30% Mussel mucin 3-10% The balance is sodium hydroxymethylcellulose; The anti-settling compound is water-based polyamide wax and / or polyamide-modified hydrogenated castor oil.

2. A method for preparing a biodegradable and recyclable bio-based emulsion as claimed in claim 1, characterized in that: The specific steps in step 2 are as follows: The surfactant, the emulsifier, the anti-settling stabilizer and the first solvent in which the bio-based particles are not dissolved are mixed evenly to obtain a dispersion A; the bio-based particles are weighed and mixed with the second solvent in which the bio-based particles are not dissolved to obtain a mixed solution B; the dispersion A and the dispersion B are mixed evenly, emulsified, and the first solvent and the second solvent in which the bio-based particles are not dissolved are removed to obtain an emulsified bio-based composite; the diluent and the emulsified bio-based composite are mixed evenly to form a bio-based emulsion.

3. The method for preparing a degradable and recyclable bio-based emulsion according to claim 1 or 2, characterized in that: The particle size of the bio-based particles is 1-2 μm.

4. A biodegradable and recyclable bio-based emulsion, characterized in that: The bio-based emulsion is obtained by the preparation method of the degradable and recyclable bio-based emulsion according to any one of claims 1 to 3, wherein the bio-based emulsion is composed of 50-80% by weight of a diluent and 20-50% by weight of a bio-based composite; the bio-based composite is composed of the following raw materials in weight percentage: Surfactant 1-5% Emulsifier 1-3% Anti-settling stabilizer 3-5% The balance is bio-based pellets.

5. An application of a biodegradable and recyclable bio-based emulsion, characterized in that: The degradable and recyclable bio-based emulsion described in claim 4 is applied to the surface of paper and dried to form a degradable coating on the surface of the paper to obtain degradable and recyclable coated paper, which is then used in food packaging.

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