A paper oil- and water-resistant coating based on cellulose cinnamate, the paper product thereof, and its preparation method

Abstract

The application discloses a cellulose cinnamate-based paper product oil / water-proof coating, a paper product and a preparation method thereof. The paper product oil / water-proof coating comprises cellulose cinnamate and an organic solvent, wherein the cellulose cinnamate has a structural formula shown in formula (1); n is a positive integer, 40<=n<=150; R1, R2 and R3 are independently selected from H or and R1, R2 and R3 are the same or different in any structural unit of the cellulose cinnamate; and at least one of R1, R2 and R3 is a group. The paper product oil / water-proof coating for paper products provided by the application aims to solve the technical problem of poor biodegradability and biosafety of the existing materials. The application provides the paper product and the preparation method thereof.

Description

Technical Field

[0001] This application belongs to the field of oil- and water-resistant coatings for paper products, specifically relating to an oil- and water-resistant coating for paper products based on cellulose cinnamate, paper products, and a method for preparing the same. Background Technology

[0002] Paper packaging materials are among the most widely used materials in the packaging industry. They are easy to process, inexpensive, suitable for mass mechanized production, and have good formability and foldability, making them ideal for fine printing. Paper packaging materials possess numerous advantages in replacing petroleum-based plastic packaging due to their complete biodegradability, bio-based origin, renewability, low price, and high designability. However, due to the inherent limitations of paper fibers, their poor barrier properties against oil and water pose significant challenges in replacing plastic packaging. Therefore, the oil and water repellency modification of paper-based materials urgently requires the development of new technologies, materials, and processes.

[0003] Currently, the oil and water resistance of paper-based packaging materials is mainly achieved by coating the surface of paper-based materials with plastic films, fluorinated compounds, acrylic emulsions, silicone emulsions, natural polymer oil and water resistant additives, and nanocomposite materials. However, these methods have various drawbacks.

[0004] Plastic lamination refers to coating a paper substrate with a thin plastic film, also known as plastic coating. Commonly used plastics for lamination include polypropylene, polyethylene, and polyethylene terephthalate. These polymers form a dense film on the paper surface, preventing water and oil from contacting the paper, thus achieving oil and water resistance. Plastic lamination is frequently used for food packaging, such as hot drink paper cups, paper bags, and takeout containers. However, using plastic film has certain drawbacks, such as the difficulty in biodegradability, which does not meet environmental protection requirements; toxic substances in the packaging may also chemically migrate into the food, compromising food safety. In conclusion, plastic or plastic composite packaging has certain shortcomings in terms of safety, environmental performance, and waste disposal, and there is room for further improvement.

[0005] Commonly used fluorinated compounds, acrylate oil and water repellents, and silicone oil and water repellents have demonstrated various excellent properties in improving the water and oil repellency of paper-based packaging materials, but each has its own certain drawbacks.

[0006] For example, paper packaging materials modified with fluorinated compounds exhibit significantly improved grease-barrier properties while still meeting appearance and performance requirements. Fluorinated oil repellents, however, are actually surfactants, which pose a significant hazard to the natural environment and living organisms.

[0007] Acrylic oil and water repellents possess good film-forming properties, imparting good strength and density to the film, and exhibiting strong surface adhesion to pulp molded packaging materials, thus giving these materials a certain degree of oil and water resistance. However, they are still non-degradable polymer materials and will continue to pose some environmental pollution problems.

[0008] Organosilicon in silicone-based oil and water repellents is a polysiloxane composed of siloxane monomers. The main chain of polysiloxane possesses the non-toxic, non-polluting, and non-corrosive properties of inorganic silica, while its side chains contain organic groups, thus exhibiting the characteristics of polymer materials. The unique -Si-O- structure in polysiloxanes gives silicone polymers excellent properties such as low surface energy, high temperature resistance, weather resistance, excellent flexibility, excellent stability in water, and non-toxicity and environmental friendliness. However, silicone-based oil and water repellents may migrate from packaging materials into food under certain circumstances. Furthermore, silicone-based oil and water repellent additives are generally not biodegradable, which may pose challenges for waste disposal.

[0009] In addition, promising oil- and water-repellent additives such as polysaccharides (e.g., starch and chitosan), proteins, and bio-waxes all have certain problems and therefore urgently need improvement. Summary of the Invention

[0010] This application provides an oil- and water-resistant coating for paper products based on cellulose cinnamate, aiming to solve the technical problem of poor biodegradability and biosafety of existing materials. This application also provides paper products with the above advantages and a method for their preparation.

[0011] In a first aspect, embodiments of this application provide an oil- and water-resistant coating for paper products based on cellulose cinnamate, comprising cellulose cinnamate and an organic solvent, wherein...

[0012] Cellulose cinnamate has the structural formula shown in formula (1):

[0013]

[0014] Where n is a positive integer, 40≤n≤150, and R1, R2, and R3 are independently selected from H or R1, R2, and R3 may be the same or different in any one of the structural units of the cellulose cinnamic acid ester, and at least one of R1, R2, and R3 is a functional group.

[0015] According to one embodiment of this application, 50 ≤ n ≤ 100.

[0016] According to one embodiment of this application, the groups in cellulose cinnamate The average degree of substitution is 0.4 to 1.5.

[0017] According to one embodiment of this application, the glass transition temperature of the cellulose cinnamic acid ester is 150–200°C.

[0018] According to one embodiment of this application, the melting temperature of the cellulose cinnamic acid ester is 180°C to 210°C.

[0019] According to one embodiment of this application, the paper product oil- and water-resistant coating comprises, by weight percentage, 18% to 80% of the cellulose cinnamic acid ester, 20% to 82% of organic solvent, and 0% to 10% of surfactant.

[0020] According to one embodiment of this application, the paper product oil- and water-resistant coating further includes a surfactant, and the paper product oil- and water-resistant coating includes, by weight percentage, 50% to 70% of the cellulose cinnamic acid ester, 50% to 30% of an organic solvent, and 1% to 5% of a surfactant.

[0021] According to an embodiment of one aspect of this application, the surfactant is selected from one or more of dodecylbenzene sulfonate, stearic acid, and stearate.

[0022] According to one embodiment of this application, the organic solvent is selected from one or more of ethanol, dimethyl sulfoxide, acetone, and ethyl acetate.

[0023] Secondly, embodiments of this application provide a method for preparing a paper product, comprising:

[0024] A first aspect of an oil- and water-resistant coating for paper products is provided, comprising cellulose cinnamate and an organic solvent, wherein the cellulose cinnamate has the structural formula shown in formula (1):

[0025]

[0026] Where n is a positive integer, 40≤n≤150, and R1, R2, and R3 are independently selected from H or R1, R2, and R3 may be the same or different in any one of the structural units of the cellulose cinnamic acid ester, and at least one of R1, R2, and R3 is a functional group.

[0027] The first aspect of the paper product oil-proof and waterproof coating is applied to the paper base material to obtain a paper product containing a waterproof and oil-proof coating.

[0028] Secondly, embodiments of this application provide a paper product, comprising:

[0029] Paper-based materials, and

[0030] A waterproof and oil-proof coating is obtained by applying an oil-proof and waterproof coating for paper products, as described in the first aspect.

[0031] This application has at least the following beneficial effects:

[0032] This application provides a paper product oil- and water-resistant coating based on cellulose cinnamate. Using cellulose cinnamate as the main component, and selecting cellulose cinnamate with a suitable degree of polymerization, is beneficial to the biodegradability, hydrophobicity, and oleophobicity of the paper product oil- and water-resistant coating. Therefore, when applied to paper products, the paper product oil- and water-resistant coating containing cellulose cinnamate is easily prepared into a coating with good hydrophobicity, and its biocompatibility and degradability are also good, thus benefiting the oil- and water-resistant performance of paper products (paper-based packaging materials) and their widespread use. This application's paper product oil- and water-resistant coating creatively uses cellulose cinnamate (commonly used as an additive in the prior art) as the main component, solving the technical problem that materials such as acrylic oil- and water-resistant agents and organosilicon oil- and water-resistant agents used in related technologies cannot be completely degraded. Furthermore, the inventors discovered during research and development that the cellulose cinnamate in this application can significantly improve the plasticity and flow properties of the polymer. Using auxiliary materials that lower the flow temperature as the main component of this application's paper product oil- and water-resistant coating solves the problems of water resistance, oil resistance, and degradability of the paper product waterproof and oil-resistant coating.

[0033] The waterproof and oil-resistant coating for paper products provided in this application has thermoplasticity, biodegradability, hydrophobicity, and biocompatibility, which improves the processing convenience, safety of use, waterproof and oil-resistant properties, and environmental performance of paper products. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0035] Figure 1 The following are 1H NMR spectra of cellulose cinnamate with different average degrees of substitution according to embodiments of this application;

[0036] Figure 2 The contact angle of water with a waterproof and oil-resistant coating comprising different cellulose cinnamic acid esters according to embodiments of this application is shown.

[0037] Figure 3 The contact angle of a waterproof and oil-repellent coating comprising different cellulose cinnamic acid esters according to an embodiment of this application with oil is shown.

[0038] Figure 4The degradation rate (weight loss) of waterproof and oil-resistant coatings containing different cellulose cinnamates from embodiments of this application is shown under aerobic composting test conditions. Detailed Implementation

[0039] To make the purpose, technical solution, and beneficial technical effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the embodiments described in this specification are merely for explaining this application and are not intended to limit it.

[0040] For simplicity, this application only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form a range not explicitly stated; and any lower limit can be combined with other lower limits to form a range not explicitly stated, just as any upper limit can be combined with any other upper limit to form a range not explicitly stated. Furthermore, although not explicitly stated, every point or individual value between the endpoints of the range is included within that range. Therefore, each point or individual value can be used as its own lower or upper limit and combined with any other point or individual value or with other lower or upper limits to form a range not explicitly stated.

[0041] In the description of this application, it should be noted that, unless otherwise stated, "above" and "below" include the stated number, and "multiple" in "one or more" means two or more.

[0042] The foregoing description of this application is not intended to describe every disclosed implementation or method. Instead, the following description provides more specific examples of exemplary embodiments. Throughout the application, guidance is provided through a series of embodiments that can be used in various combinations. The examples listed are representative only and should not be construed as exhaustive.

[0043] Oil and water repellent coatings for paper products based on cellulose cinnamate

[0044] In a first aspect, embodiments of this application provide an oil- and water-resistant coating for paper products based on cellulose cinnamate, comprising cellulose cinnamate and an organic solvent.

[0045] According to the embodiments of this application, a suitable cellulose cinnamic acid ester is selected, which has certain hydrophobic properties, which is beneficial to improving the hydrophobicity of the oil-proof and waterproof coating for paper products.

[0046] According to the embodiments of this application, cellulose cinnamate, as the main component of oil- and water-resistant coatings for paper products, has good biodegradability, hydrophobicity, thermal adhesion, thermal processing performance and barrier properties, and when it is made into a coating, it has good transparency.

[0047] The types of cellulose cinnamates can be detected using techniques known in the art, such as nuclear magnetic resonance (NMR) and mass spectrometry. As an example, the types of cellulose cinnamates can be determined by NMR or infrared spectroscopy. Furthermore, the types of cellulose cinnamates can be obtained by the molar-to-mass ratio of the raw materials added during the preparation process. Cellulose cinnamates can be obtained through in-house preparation or by commercial purchase.

[0048] Typically, cellulose cinnamates obtained using existing technologies also contain certain impurities. These impurities can be polymers at positions such as hydrogen and hydroxyl groups in the cellulose cinnamate, substituted with halogen atoms such as chlorine. Based on the total mass of the cellulose cinnamate, it contains 0% to 3.5% impurities. As an example, impurities may include the following general structural formula:

[0049] Where n is a positive integer, 40≤n≤150, and R1, R2, and R3 are independently selected from H, Cl, I, Br.

[0050] In some alternative embodiments, cellulose cinnamate has the structural formula shown in formula (1):

[0051]

[0052] Where n is a positive integer, 40≤n≤150, and R1, R2, and R3 are independently selected from H or And at least one of R1, R2, and R3 is included. According to the embodiments of this application, R1, R2, and R3 are independently selected from H, This can be understood as follows: in any one of the n structural units of cellulose cinnamate, R1, R2, and R3 can be H or H respectively. In each structural unit, the types of groups R1, R2, and R3 can be the same or different. For example, in one structural unit, R1, R2, and R3 can all be H, while in another structural unit, R1, R2, and R3 can be... In another structural unit, R1, R2, and R3 are H, respectively.

[0053] At least one of R1, R2, and R3 is This can be understood as follows: in the n structural units of cellulose cinnamate, as long as there is a group at position R1, R2, or R3 in any one structural unit... That's all.

[0054] According to the embodiments of this application, the raw materials cellulose and cinnamic acid (or cinnamic acid substituted with halogens) of cellulose cinnamate have good biocompatibility, and therefore cellulose cinnamate has good biocompatibility.

[0055] Furthermore, the cellulose cinnamate with the above-mentioned suitable degree of polymerization has a suitable number of glycosidic bonds, which are easily degradable, and the cellulose cinnamate with the degree of polymerization of this application has good degradability.

[0056] The value of n can be any number or a range of values ​​from 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, and 150.

[0057] When the degree of polymerization (n) of cellulose cinnamate is less than the minimum value mentioned above, coatings prepared with it as the main component exhibit poor film-forming properties and are prone to delamination and cracking. When the degree of polymerization (n) of cellulose cinnamate is greater than the maximum value mentioned above, coatings prepared with it as the main component are affected to some extent, resulting in a significant decrease in the degradation rate of the coating, which is detrimental to the environmental friendliness and degradation of the material. The degree of polymerization of cellulose cinnamate can be characterized by the copper ethylenediamine method.

[0058] In some alternative implementations, 50 ≤ n ≤ 100.

[0059] The value of n can be any number of 50, 60, 70, 80, 90, 100 or a range thereof.

[0060] According to embodiments of this application, the polymer of cellulose cinnamate having the above-described structure has n repeating structural units, and the degree of polymerization n is within the above-described range, which is beneficial to the degradability and film-forming properties of cellulose cinnamate. Cellulose cinnamate also possesses specific chemical properties, such as suitable melting temperature, biocompatibility, and biosafety. Therefore, using it as a main component in oil- and water-resistant coatings for paper products, applied to paper-based packaging materials, improves their biosafety or reliability and degradability, thus enhancing the water- and oil-resistant properties of the paper-based packaging materials.

[0061] In addition, cellulose cinnamate has hydrophobic functional groups, such as the benzene ring in cinnamic acid; these hydrophobic functional groups help to make cellulose cinnamate hydrophobic.

[0062] In some embodiments, the coating containing cellulose cinnamate exhibits a degradation rate of over 60% after 7 days of enzyme treatment and over 80% after 42 days of composting treatment, demonstrating its good biodegradability.

[0063] Biodegradability testing methods can be based on, for example, international standard ISO 14855 or its equivalent ASTM D5338 / ASTM D6400, and certified by an independent testing laboratory. Alternatively, ASTM D6400 can be used as the standard specification for plastic labels for aerobic composting in municipal or industrial facilities, and is applicable to the materials used in the structure and / or finished product according to the present invention.

[0064] Cellulose cinnamate has a main structure containing glycosidic bonds, which gives it good degradability. Furthermore, the degree of polymerization of cellulose cinnamate is within the aforementioned range, which further enhances its degradability.

[0065] In some embodiments, cellulose cinnamate at a concentration of 0.5 mg / mL showed no toxicity to human epidermal cells, indicating good biocompatibility. Biocompatibility can be assessed according to the in vitro cytotoxicity tests in Part 5 of the ISO 10993 series of standards.

[0066] In some alternative embodiments, the groups in cellulose cinnamate

[0067] The average degree of substitution is 0.4 to 1.5, and can be selected as 0.45 to 1.2.

[0068] Optionally, the above average degree of substitution can be any value or a range of combinations thereof from 0.4, 0.5, 0.6, 0.8, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5.

[0069] It is understandable that the average degree of substitution can be interpreted as R1, R2, and R3 being... The ratio of the number of structures shown to the total number of R1, R2, and R3. As an example, for instance, when n is 10, this cellulose cinnamic acid ester has 12 groups. The average degree of substitution at any of the R1, R2, and R3 positions is calculated as 12 / 30 = 0.4. The average degree of substitution in this application can be obtained through testing.

[0070] like Figure 1 As shown, Figure 1 The H-NMR spectra of cellulose cinnamate with different average degrees of substitution are shown.

[0071] According to the embodiments of this application, cellulose cinnamate has the above-mentioned average degree of substitution, and therefore has specific chemical properties, such as suitable melting temperature, biocompatibility, and biosafety. Therefore, it is used as a main component in paper product oil and water resistant coatings, which are applied to paper-based packaging materials to improve their biosafety or reliability, and also to improve the water and oil resistant properties of paper-based packaging materials.

[0072] Furthermore, cellulose cinnamate with the above-mentioned average degree of substitution exhibits good hydrophobicity and oleophobicity, and also has good degradability.

[0073] The aforementioned average degree of substitution can be detected using techniques known in the art, such as nuclear magnetic resonance (NMR) and mass spectrometry. NMR can be used to characterize the average degree of substitution of the groups in the cinnamic acid ester moiety.

[0074] As an example, the method for testing 1H NMR spectroscopy is as follows: Take 5mg of the obtained cellulose cinnamate sample, add 0.5ml of deuterated dimethyl sulfoxide-d6 (DMSO-d6) to dissolve it, add half a drop of deuterated trifluoroacetic acid after dissolution, and test it at room temperature on a Bruker DMX30 instrument with 32 scans to obtain the above results.

[0075] In some alternative embodiments, the glass transition temperature of the cellulose cinnamate is 150-200°C.

[0076] Optionally, the glass transition temperature of cellulose cinnamate can be any value or a range of combinations thereof from 150°C, 160°C, 170°C, 180°C, 190°C, and 200°C.

[0077] According to embodiments of this application, the glass transition temperature Tg can affect the waterproof properties and processing properties of cellulose cinnamate.

[0078] Furthermore, the Tg value is related to the flexibility and bending properties of cellulose cinnamate. The aforementioned glass and temperature conditions allow for the application of oil- and water-resistant coatings to paper products, resulting in greater flexibility at low temperatures and better bending properties.

[0079] The glass transition temperature (Tg) is the temperature between the glassy and rubbery states of a material, representing the transition from a hard and brittle state to a soft and elastic state. The glass transition temperature (Tg) of cellulose cinnamate is a well-known concept in the art and can be measured using instruments and methods known in the field, such as high-temperature gel permeation chromatography. Differential scanning calorimetry, thermodynamic analysis, and thermal expansion methods can also be used for testing.

[0080] As an example, the glass transition temperature can be tested as follows: Take 3 mg of the sample obtained in the example and test it on a TA Instruments Q2000 differential scanning calorimeter. To eliminate thermal history, the sample is first heated from 20°C to 280°C at a heating rate of 20°C / min. Hold the temperature for 1 minute; then rapidly cool to 50°C and hold for 2 minutes; finally, heat from 50°C to 280°C at a rate of 20°C / min. The glass transition temperature is then measured by a second heating scan.

[0081] In some alternative embodiments, the melting temperature of cellulose cinnamate is 180-210°C.

[0082] The melting temperature of cellulose cinnamate is a well-known concept in the art and can be measured using instruments and methods known in the field. Examples include differential scanning calorimetry, thermogravimetric analysis, and infrared spectroscopy. As an example, infrared spectroscopy analysis can be used to observe the molecular structural changes of cellulose cinnamate during the melting process, thereby obtaining information about its melting temperature. As an example, the melt flow temperature of this application can range from 1 to 7 g / m³. 2 The amount of cellulose cinnamate was tested. The melting temperature can be selected from 190°C to 200°C. The method for testing the melting temperature is as follows: Take about 1 mg of the sample obtained in the example and place it in a THMS600 heating stage from Linkma (UK); place the heating stage with the sample in a BX51 optical microscope from Olympus (Japan) for observation; the heating stage is heated from 20°C to 280°C at a heating rate of 10°C / min. Observe the temperature at which the polymer begins to flow.

[0083] In some alternative embodiments, the oil- and water-resistant coating for paper products comprises, by weight percentage, 18% to 80% of the cellulose cinnamic acid ester, 20% to 82% of organic solvent, and 0% to 10% of surfactant.

[0084] According to the embodiments of this application, the above-mentioned oil- and water-resistant coating for paper products uses cellulose cinnamic acid ester as the main component, which has good degradability and is therefore not easy to pollute the environment and has good biosafety. Therefore, the oil- and water-resistant coating for paper products of this application has excellent environmental performance.

[0085] The 0%–10% surfactant indicates that surfactants may or may not be added to the oil- and water-resistant coating for paper products. 0% surfactant can be understood as meaning that, in one embodiment, no surfactant is added to the oil- and water-resistant coating for paper products. Adding surfactants can further improve the dispersibility of the components in the oil- and water-resistant coating for paper products, thereby increasing the uniformity of the coating.

[0086] In addition, the film layer formed with cellulose cinnamate as the main component has good transparency, which can meet the visualization requirements of related product packaging.

[0087] In some optional embodiments, the paper product oil- and water-resistant coating further includes a surfactant, wherein the paper product oil- and water-resistant coating comprises, by weight percentage, 50% to 70% of the cellulose cinnamic acid ester, 50% to 30% of an organic solvent, and 1% to 5% of a surfactant.

[0088] According to the embodiments of this application, the paper product oil- and water-resistant coatings with the above-mentioned components and contents have good biodegradability, hydrophobicity, and biosafety.

[0089] In this application, the specific type of surfactant can be selected from a wide range, but in order to make the resulting oil- and water-resistant coating for paper products have better adhesion and waterproofing effects, in some optional embodiments, the surfactant is selected from one or more of dodecylbenzene sulfonate, stearic acid, and stearate.

[0090] According to the embodiments of this application, the surfactants of the above types improve the adhesion and coverage of the coating formed by the oil- and water-resistant coating for paper products; the surfactants can reduce the surface tension of the liquid, making it easier to distribute evenly on the substrate surface; they can form a thin film in the coating, which is beneficial to improving the resistance of the oil- and water-resistant coating for paper products to water and oil.

[0091] In this application, the specific type of organic solvent can be selected from a wide range, but in order to make the resulting oil- and water-resistant coating for paper products have a better waterproof effect, in some optional embodiments, the organic solvent is selected from one or more of ethanol, dimethyl sulfoxide, acetone, and ethyl acetate.

[0092] According to the embodiments of this application, the above-mentioned organic solvents can uniformly disperse cellulose cinnamate, which is beneficial for the uniform distribution of oil- and water-resistant coatings on the substrate surface; and is beneficial for improving the hydrophobicity and oil resistance of the coating formed by the oil- and water-resistant coatings on paper products.

[0093] The components in the oil- and water-resistant coating for paper products can be directly mixed, or the cellulose cinnamate and organic solvent can be mixed evenly first before adding the surfactant to further improve the dispersibility of the oil- and water-resistant coating for paper products, improve the uniformity of the coating prepared by the subsequent oil- and water-resistant coating for paper products, and improve the surface roughness of the coating.

[0094] A method for preparing cellulose cinnamate includes: mixing an organic solution containing cellulose with cinnamic acid or a halocinnamic acid in an aqueous solution, thereby reacting the cellulose with the cinnamic acid or halocinnamic acid to obtain cellulose cinnamate. The organic solution includes a first organic solvent. The first organic solvent may be a carbamate or the like, used to dissolve the cellulose.

[0095] Preparation methods of paper products

[0096] Secondly, embodiments of this application provide a method for preparing a paper product, comprising:

[0097] A first aspect of an oil- and water-resistant coating for paper products is provided, comprising cellulose cinnamate and an organic solvent, wherein the cellulose cinnamate has the structural formula shown in formula (1):

[0098]

[0099] Where n is a positive integer, 40≤n≤150, and R1, R2, and R3 are independently selected from H or And at least one of R1, R2, and R3 is included.

[0100] The first aspect of the paper product oil-proof and waterproof coating is applied to the paper base material to obtain a paper product containing a waterproof and oil-proof coating.

[0101] According to any embodiment of this application, the paper-based material can be a product made by turning cellulose fibers into paper or pulp or by processing a pulp mixture into an article of desired shape, and then drying and curing it.

[0102] In some embodiments, based on the total mass of the organic solution, the organic solution comprises, by mass percentage, 18% to 80% of the cellulose cinnamic acid ester, 20% to 82% of organic solvent, and 0% to 10% of surfactant.

[0103] According to any embodiment of this application, the paper product may be a paper product or a pulp molded product.

[0104] According to embodiments of this application, coating is a processing method that forms a coating layer by applying a liquid to the surface of a substrate. There are various coating methods, such as spraying, roller coating, and spraying. As an example, an organic solution containing cellulose cinnamate is applied to a pre-formed molded pulp semi-finished product by spraying, followed by drying to obtain a molded pulp article.

[0105] Paper products

[0106] Secondly, embodiments of this application provide a paper product, comprising:

[0107] Paper-based materials, and

[0108] A waterproof and oil-resistant coating is obtained by applying a paper product oil- and waterproof coating based on cellulose cinnamic acid esters, as described in the first aspect.

[0109] According to any embodiment of this application, the paper-based material can be a product made by turning cellulose fibers into paper or pulp or by processing a pulp mixture into an article of desired shape, and then drying and curing it.

[0110] According to any embodiment of this application, the paper product may be a paper product or a pulp molded product.

[0111] According to any embodiment of this application, the paper product can be made by turning cellulose fibers into paper or pulp, and its surface can have the above-mentioned waterproof and oil-resistant coating, thereby improving its waterproof and oil-resistant properties.

[0112] Paper products can be used to manufacture a variety of paper-based products. Pulp molded products are typically made by processing a pulp mixture into the desired shape, followed by drying and curing. Their surface can have the aforementioned waterproof and oil-resistant coating, thus improving their waterproof and oil-resistant properties.

[0113] Paper products and molded pulp products are lightweight, printable, and recyclable. Generally speaking, molded pulp products tend to focus more on customized shapes and environmentally friendly requirements, and are suitable for some application fields that require special shapes and functions. Therefore, the biodegradability and biosafety of the waterproof and oil-proof coating of the above-mentioned paper products are very important.

[0114] Example

[0115] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on weight, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0116] Example 1

[0117] This embodiment provides a method for preparing cellulose cinnamate, including:

[0118] Step 1: Preparation of low-polymerization-degree cellulose: 5 L of 80% phosphoric acid aqueous solution was added to a reactor. Then, 500 g of microcrystalline cellulose with a degree of polymerization (DP) of 220, sourced from Sinopharm Group, was added and uniformly dispersed under stirring. After stirring continuously at 30°C for 4 hours, 20 L of deionized water was added, and the mixture was immediately neutralized with sodium bicarbonate to pH = 7 to obtain a crude product. The crude product was washed sequentially with water and acetone. To further refine the product, the washed crude product powder was dispersed in 5 L of dimethyl sulfoxide and placed at 100°C for 3 hours. After drying, cellulose powder with a degree of polymerization (DP) of 100 was obtained.

[0119] Step 2, Preparation of cellulose cinnamate: 800g of the above cellulose was added to 19.2kg of carbamate (AmimCl) and stirred vigorously at 80℃ for 1 hour to dissolve, thus preparing a cellulose / AmimCl solution with a concentration of 4wt%.

[0120] A cellulose solution was placed in water, and cinnamoyl chloride was added at a molar ratio of cellulose to cinnamoyl chloride of 1:2. The reaction was allowed to proceed for a certain period of time. After the reaction was complete, ethanol was added to precipitate the cellulose, which was then filtered through a sintered glass funnel, washed three times, and dried. The dried sample was dissolved in dimethyl sulfoxide (DMSO), precipitated again with methanol or isopropanol, filtered, washed three times, and finally dried in a vacuum oven at 60°C to obtain cellulose cinnamate with an average degree of substitution of 1.42 and a melting temperature of 190°C.

[0121] This embodiment provides a method for preparing an oil- and water-resistant coating for paper products based on cellulose cinnamate, comprising:

[0122] 1.2 kg of cellulose cinnamate powder was added to 6 liters of ethanol and then dispersed using a high-speed disperser to obtain an oil-proof and waterproof coating for paper products, namely a cellulose cinnamate / ethanol dispersion.

[0123] This embodiment provides a method for preparing an oil- and water-resistant molded pulp product:

[0124] The cellulose cinnamate / ethanol dispersion prepared above was applied to the molded pulp product by spraying, followed by drying to obtain a pulp molded product with a waterproof and oil-resistant coating. Testing showed that the waterproof and oil-resistant coating is usable and meets the testing standards for waterproof and oil-resistant coatings on paper products.

[0125] Example 2

[0126] The difference between this embodiment and Example 1 is that the molar ratio of cellulose to cinnamoyl chloride is 1:1.5, the resulting cellulose cinnamate has a melting temperature of 200°C, and its average degree of substitution is 1.19.

[0127] Example 3

[0128] The difference between this embodiment and Example 1 is that the molar ratio of cellulose and cinnamoyl chloride is 1:1, the resulting cellulose cinnamate has a melting temperature of 200°C, and its average degree of substitution is 0.45.

[0129] Example 4

[0130] The difference between this embodiment and Example 1 is that the molar ratio of cellulose to cinnamoyl chloride is 1:3, and the resulting cellulose cinnamate has a melting temperature of 180°C and an average...

[0131] The degree of substitution is 2.40.

[0132] Example 5

[0133] This embodiment provides a method for preparing cellulose cinnamate, including:

[0134] 5 L of 80% phosphoric acid aqueous solution was added to a reaction vessel. Then, 500 g of microcrystalline cellulose was added and dispersed uniformly with stirring. After stirring continuously at 40°C for 4 hours, 20 L of deionized water was added, and the mixture was immediately neutralized with sodium bicarbonate to pH 7. The crude product was washed sequentially with water and acetone. To further refine the product, the powder was dispersed in 5 L of dimethyl sulfoxide and allowed to stand at 100°C for 3 hours. Finally, a cellulose powder with a DP value of 100 was obtained.

[0135] 800g of the cellulose powder obtained above was added to 19.2kg of the ionic liquid AmimCl and stirred vigorously at 80℃ for 1 hour to dissolve, preparing a 4wt% cellulose / AmimCl solution. The cellulose solution was placed in water, and a certain amount of cinnamoyl chloride was added, and the reaction was allowed to proceed for a certain period of time. After the reaction was completed, ethanol was added to precipitate the cellulose, which was then filtered, washed three times, and dried. The dried sample was dissolved in DMSO, precipitated again with methanol or isopropanol, filtered, washed three times, and finally dried in a vacuum oven at 60℃. The molar ratio of cellulose to cinnamoyl chloride was 1:2. The resulting cellulose cinnamate had a melting temperature of 190℃ and an average degree of substitution of 1.46.

[0136] This embodiment provides a method for preparing an oil- and water-resistant coating for paper products based on cellulose cinnamate, comprising:

[0137] 1.2 kg of cellulose cinnamate powder was added to 6 liters of ethanol and then dispersed using a high-speed disperser to obtain an oil-proof and waterproof coating for paper products, namely a cellulose cinnamate / ethanol dispersion.

[0138] This embodiment provides a method for preparing an oil- and water-resistant molded pulp product:

[0139] The above-mentioned cellulose cinnamate / ethanol dispersion was applied to the molded pulp product by spraying and then dried to obtain a molded pulp product with a waterproof and oil-resistant coating.

[0140] Example 6

[0141] The difference between this embodiment and Example 5 is that the molar ratio of cellulose to cinnamoyl chloride is 1:1.5, the resulting cellulose cinnamate has a melting temperature of 200°C, and its average degree of substitution is 0.77.

[0142] According to the experiment, replacing ethanol in the above examples with organic solvents such as dimethyl sulfoxide, acetone, and ethyl acetate to prepare oil- and water-resistant coatings for paper products resulted in pulp molding products with a significant technical effect.

[0143] Experiments showed that adding 1.2 kg of cellulose cinnamate powder to 6 liters of ethanol to obtain a mixture, and then adding 3% by mass of sodium stearate as a surfactant, yielded an oil- and water-resistant coating for paper products. This coating exhibited good dispersibility and excellent uniformity of the oil- and water-resistant coating. Replacing the aforementioned surfactant with other surfactants such as sodium dodecylbenzene sulfonate or stearic acid also resulted in good dispersibility and excellent uniformity of the oil- and water-resistant coating.

[0144] In addition, experiments have shown that adding 1% to 10% of the above-mentioned surfactants can improve the dispersibility of oil- and water-resistant coatings for paper products and improve the uniformity of the oil- and water-resistant coating.

[0145] Comparative Example 1

[0146] The difference between this embodiment and Example 5 is that the obtained cellulose cinnamate has an average degree of substitution of 1.0, a degree of polymerization of 180, poor biodegradability, and is not suitable for preparing waterproof and oil-resistant coatings.

[0147] Performance testing

[0148] Water resistance testing method: The water contact angle of the waterproof and oil-resistant coating on the surface of the pulp molded product was tested according to the ASTM D7490-13 standard. The results are shown in Table 1 and... Figure 2 As shown.

[0149] The method for testing oil-repellent performance: The oil barrier properties of the waterproof and oil-repellent coating on the surface of the pulp molded product were tested according to ASTM D7490-13 standard (using commercially available soybean oil). The results are shown in Table 1 and... Figure 3 As shown.

[0150] Water permeability test: According to GB / T 1037 standard, water vapor transmission rate w1 (g / m 2 The pulp molding products of the examples were measured in an ambient gas environment of 38°C and 90% RH, and the results are shown in Table 1.

[0151] Aerobic composting degradation test: The product with the protective cellulose cinnamate film from the example was fixed on a PE mesh (2×2mm). 2 The soil was placed between mesh sizes and buried in compost soil within a sealed container. The container was placed in an incubator at 60°C, and opened every 24 hours to supply oxygen. Water was added to maintain the soil at 50% moisture content. The results were measured as follows: Figure 4 As shown, this illustrates that the products of Examples 1-6 have good degradability.

[0152] Table 1

[0153]

[0154] The above results demonstrate that the pulp molding products made using the oil- and water-resistant coating of this application have good water contact angles and oil contact angles, thus indicating that the water- and oil-resistant coating containing cellulose cinnamate in this application has good oil- and water-resistant properties. Furthermore, the water- and oil-resistant coating prepared with cellulose cinnamate of suitable polymer and average degree of substitution is easily degradable and is a product worthy of promotion.

[0155] Performance grading test: The waterproof and oil-proof coatings on the surface of the pulp molded products prepared in the examples and comparative examples were graded for their waterproof and oil-proof performance, as well as their degradation performance. The results are shown in Table 2.

[0156] Table 2

[0157]

[0158]

[0159] Based on the results of the examples and comparative examples, it is evident that the waterproof and oil-repellent coating prepared using cellulose cinnamate exhibits superior waterproof and oil-repellent properties. In contrast, Comparative Example 1 used cellulose cinnamate with a degree of polymerization of 180 to prepare the waterproof and oil-repellent coating. Cellulose cinnamate is prone to crystallization, difficult to process, and biodegradable, making it unsuitable for preparing the waterproof and oil-repellent coating of this application.

[0160] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A paper product oil and water repellent coating based on cellulose cinnamate, said paper product oil and water repellent coating consisting of 18 to 80 % by mass of said cellulose cinnamate, 20 to 82 % of an organic solvent, 0 to 10 % of a surfactant, wherein, The cellulose cinnamate has a structural formula shown in formula (1): ； wherein n is a positive integer, 40 < n < 150, R1, R2, R3are independently selected from H or, R1, R2, R3are the same or different in any one structural unit of the cellulose cinnamate, and at least one of R1, R2, R3is a group , the average degree of substitution of the group in the cellulose cinnamate is 0.4 to 1.

5.

2. The paper product oil and water repellent coating according to claim 1, wherein, 50≤n≤100。 3. The paper product oil and water repellent coating according to claim 1, wherein The cellulose cinnamate satisfies at least one of the following conditions: 1) The glass transition temperature of the cellulose cinnamate is 150-200℃; 2) The melting temperature of the cellulose cinnamate is 180-210℃.

4. The paper product oil and water repellent coating according to claim 1, wherein, The paper product oil / water repellent coating further comprises a surfactant, and the paper product oil / water repellent coating comprises 50-70% of the cellulose cinnamate, 50-30% of an organic solvent, and 1-5% of the surfactant by mass percentage.

5. The paper product oil / water repellent coating according to claim 1, wherein the surfactant is selected from one or more of dodecyl benzene sulfonate, stearic acid, and stearate.

6. The paper product oil / water repellent coating according to claim 1, wherein the organic solvent is selected from one or more of alcohol, dimethyl sulfoxide, acetone, and ethyl acetate.

7. A method of making a paper product, characterized by Comprising: The paper product oil / water repellent coating based on cellulose cinnamate according to any one of claims 1-6 comprises cellulose cinnamate and an organic solvent, wherein the cellulose cinnamate has a structural formula shown in formula (1): ； wherein n is a positive integer, 40 < n < 150, R1, R2, R3are independently selected from H or R1, R2, R3are the same or different in any one structural unit of the cellulose cinnamate, and at least one of R1, R2, R3is a group ; The paper product oil / water repellent coating is applied to a paper base material to obtain a paper product comprising an oil / water repellent coating.

8. A paper product, characterized in that Comprising: A paper base material, and The oil / water repellent coating is prepared by applying the paper product oil / water repellent coating based on cellulose cinnamate according to any one of claims 1-6.

Images