A biodegradable high barrier (water, oil, oxygen, water, steam) paper-based packaging material and its preparation method

Abstract

The present invention provides a biodegradable high-barrier (water, oil, oxygen, water, steam) paper-based packaging material and a preparation method thereof, belonging to the field of high-barrier functional materials. There are five layers in total, namely, a base paper layer, a starch layer, a polyethylene layer, a polyepoxy oil resin layer, and a polyacrylic resin layer. The starch layer is the base coating of the paper, providing a smooth interface for the next layer of coating; the polyvinyl alcohol layer is an oxygen- and oil-proof layer, achieving a high-efficiency barrier to oxygen and oil; the polyepoxy oil resin layer is a water-, oil-, and moisture-proof layer, especially having an excellent effect in preventing the penetration of water vapor; the water-based acrylic resin layer is a waterproof and oil-proof layer, which can effectively prevent the impregnation of water and oil, and at the same time provide good heat-sealing properties for the paper-based material. The paper-based packaging material produced by the present invention has good moisture-proof, oxygen-proof, waterproof, and oil-proof functions, and the materials used are green, environmentally friendly, food-contactable, and biodegradable. Therefore, it is of great significance in replacing plastic food packaging materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-barrier functional materials, and in particular relates to a biodegradable high-barrier (water, oil, oxygen, water vapor) paper-based packaging material and a preparation method thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Currently, traditional aluminum-plastic composite packaging is widely used in the field of high-barrier packaging both domestically and internationally. However, these materials typically consume significant amounts of non-renewable resources, and their tight interlayer bonding makes recycling difficult. Furthermore, aluminum-plastic composites are poorly biodegradable, and their widespread use creates significant environmental pollution.

[0004] Currently, reports have emerged on biodegradable high-barrier materials that can replace aluminum-plastic composite materials. For example, patent CN113619242A discloses a biodegradable high-barrier paper-plastic packaging composite film and its preparation method. The composite film comprises, from the outside to the inside, an ink layer, a paper layer, a barrier coating, an adhesive layer, and a PLA layer. The barrier layer utilizes a PVA coating. The modified PLA layer improves heat resistance and toughness, while also ensuring heat-sealing properties. Although the resulting packaging composite film is biodegradable, it may lack moisture and water resistance compared to aluminum-plastic composite materials because the PVA coating in the barrier layer is a hydrophilic polymer. Patent CN209777145U discloses a new high-barrier packaging bag that utilizes coatings such as polyethylene film, PVA film, and PVDC resin film to enhance the bag's sealing performance. However, it is well known that while PVDC resin has excellent barrier properties, it is difficult to biodegrade. Therefore, many currently disclosed methods for preparing high-barrier packaging materials often have poor biodegradability while meeting high-barrier properties; and some biodegradable materials have the disadvantage of poor high-barrier properties. Summary of the Invention

[0005] To address these issues, the present invention provides a biodegradable paper-based packaging material with a high barrier to water, oil, oxygen, and water vapor, and a method for its preparation. This invention utilizes dimethyl itaconate or 1,2-ethylene glycol dimethacrylate as monomers, polymerized with epoxidized soybean oil acrylate, to synthesize a novel polyepoxy oleoresin. This material significantly reduces water vapor transmission and improves biodegradability. Furthermore, the present invention utilizes environmentally friendly materials such as starch, PVA (polyvinyl alcohol), polyepoxy oleoresin, and a water-based acrylic resin to produce a paper-based packaging material with excellent moisture, oxygen, water, and oil resistance. The preparation method is simple and readily available, and it is expected to offer a promising alternative to aluminum-plastic composite materials in the future.

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

[0007] In a first aspect, the present invention provides a biodegradable high barrier (water, oil, oxygen, water, steam) paper-based packaging material comprising: a base paper layer, a starch layer, a polyethylene layer, a polyepoxy oil resin layer, and a polyacrylic acid resin layer, arranged in order from bottom to top;

[0008] The coating amount ratio of the starch layer, polyethylene layer, polyepoxy oil resin layer and polyacrylic acid resin layer is 0.5-1.5:5.5-7.5:3.5-3.7:6.1-6.5;

[0009] The preparation method of the polyepoxy oil resin layer comprises: using dimethyl itaconate or 1,2-ethylene glycol dimethacrylate as a monomer and polymerizing it with epoxy soybean oil.

[0010] To address the poor biodegradability and recycling challenges of existing aluminum-plastic composite packaging materials, this invention provides a biodegradable paper-based packaging material with high barrier properties (to water, oil, oxygen, and water vapor) and its preparation method. The material is environmentally friendly, biodegradable, and exhibits excellent barrier properties, while also being simple to prepare.

[0011] In some embodiments, the starch raw material used in the starch layer is natural starch or modified starch;

[0012] The natural starch includes: potato starch, bean starch, cereal starch, and vegetable starch;

[0013] The modified starch includes: anionic starch, cationic starch, amphoteric and multi-modified starch, and nonionic starch.

[0014] The starch was gelatinized and evenly coated on the surface of the base paper and dried. The coating amount was 0.4 g / m 2 ~1.8g / m 2 .

[0015] In some embodiments, the polyvinyl alcohol material used in the polyethylene layer is polyvinyl alcohol.

[0016] The above mentioned product categories include 0599, 1799, 1788, 2499, 2488 and other models, with a solid content of 15%, dissolved at 90 ° C, evenly coated on the surface of the starch layer and dried, with a coating amount of 5.3g / m 2 ~7.7 g / m 2 .

[0017] In some embodiments, the polyepoxy oil resin layer is formed by polymerizing one or more mixtures of epoxy soybean oil acrylate and methyl acrylate, butyl acrylate, isooctyl acrylate, dimethyl itaconate, 1,4-butanediol diacrylate, 1,2-ethylene glycol dimethacrylate, etc.

[0018] In the synthesis process of the polyepoxy oil resin, the ester monomers used include one or more mixtures of methyl acrylate, butyl acrylate, isooctyl acrylate, dimethyl itaconate, 1,4-butanediol diacrylate, 1,2-ethylene glycol dimethacrylate, etc.; the epoxy oil acrylate used is epoxy soybean oil acrylate.

[0019] In order to obtain better barrier properties, this application also screened the types and amounts of ester monomers. Preferably, dimethyl itaconate and 1,2-ethylene glycol dimethacrylate were used as monomers to polymerize with epoxy soybean oil acrylate, which can better reduce the water vapor transmission rate and at the same time, the biodegradation rate was also improved.

[0020] In some embodiments, the polyacrylic resin layer is a water-based acrylic resin emulsion or a water-based acrylic resin emulsion dispersed with 1% to 10% glyceryl stearate, vegetable oil triglyceride, neopentyl glycol dioleate, trimethylolpropane trioleate, epoxydized soybean oil, or triglycerol. Emulsion types include pure acrylic, styrene acrylic, and styrene butadiene emulsions.

[0021] In order to obtain better barrier properties, this application also screened the types and amounts of lipids. Preferably, the use of a water-based acrylic resin emulsion compounded with 10% triglyceride can obtain better waterproof and oil-proof properties. At the same time, the biodegradation rate is also improved.

[0022] A second aspect of the present invention further provides a method for preparing a biodegradable high barrier (water, oil, oxygen, water, steam) paper-based packaging material, comprising:

[0023] The starch is gelatinized and evenly coated on the surface of the base paper and dried to obtain a starch layer;

[0024] dissolving polyvinyl alcohol and coating it on the starch layer, and drying to obtain a polyethylene layer;

[0025] The epoxy soybean oil acrylate, acrylates, and photoinitiator are uniformly mixed to obtain a mixed solution;

[0026] coating the mixed solution on the polyethylene layer and light curing the mixture to obtain a polyepoxy oil resin layer;

[0027] A water-based acrylic resin emulsion is coated on the polyepoxy oil resin layer and dried to obtain a polyacrylic resin layer.

[0028] In some embodiments, the mass ratio of epoxy soybean oil acrylate is 60% to 80%, the mass ratio of acrylate monomer is 20% to 40%, and the added amount of photoinitiator is 2% to 4%.

[0029] In some embodiments, the photoinitiator is a commercial cationic initiator such as 1173, 184, 907, etc. The above-mentioned component compounds are fully mixed and evenly coated on the polyvinyl alcohol coating, and then cured under ultraviolet light for 0.5s to 1s.

[0030] In some embodiments, the curing time under ultraviolet light irradiation is 0.5s to 1s.

[0031] The third aspect of the present invention also provides a biodegradable high barrier (water, oil, oxygen, water vapor) paper-based packaging material prepared by the above method.

[0032] Beneficial effects of the present invention

[0033] (1) The coating structure of the present invention mainly consists of five layers, namely, a base paper layer, a starch layer, a polyethylene layer, a polyepoxy oil resin layer, and a polyacrylic resin layer. The starch layer is the base coating of the paper, providing a smooth interface for the next coating layer; the polyethylene layer is an oxygen and oil barrier layer, achieving a high barrier to oxygen and oil; the polyepoxy oil layer is a water, oil, and moisture barrier layer, especially having an excellent effect in preventing the permeation of water vapor; the acrylic resin layer is a waterproof and oil-proof layer, which can effectively prevent water and oil from penetrating and at the same time provide a certain heat-sealing performance for the packaging paper.

[0034] (2) The paper-based packaging material produced using the present invention has excellent barrier properties (moisture barrier, oxygen barrier, water barrier, and oil barrier). The coating material used is environmentally friendly, food-contactable, biodegradable, and easily marketable. The preparation method is simple. Therefore, it has a certain alternative to current aluminum-plastic composite packaging materials.

[0035] (3) The preparation method of the present invention is simple, practical, and easy to promote. DETAILED DESCRIPTION

[0036] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0037] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are intended to explain the present invention rather than to limit it.

[0038] Example 1

[0039] (1) Coating of starch layer:

[0040] At a basis weight of 30 g / m 2 The glossy side of the tissue paper is 0.7 g / m 2 Apply gelatinized starch in a coating amount and dry it at room temperature. Be careful not to cause wrinkles and keep the paper surface flat.

[0041] (2) Coating of polyethylene layer:

[0042] Dissolve polyvinyl alcohol with a solid content of 15% in deionized water, and then add 5.8 g / m 2 Apply the coating amount on the starch layer dried in step (1), keep it flat, and dry it at room temperature;

[0043] (3) Coating of polyepoxy resin layer:

[0044] Add 30% methyl acrylate and 4% brand 1173 photoinitiator to epoxy soybean oil, place it in a heat-collecting constant temperature heating magnetic stirrer to fully mix and react, set the temperature to 85℃, the stirring speed to 400rpm, the mixing time to 30min, and after mixing, coat it with a coating amount of 3.5g / m 2 The coating amount is applied on the polyvinyl alcohol coating dried in step (2), and then irradiated under ultraviolet light for 1 second for curing;

[0045] (4) Coating of polyacrylic resin layer:

[0046] Pure acrylic emulsion was mixed with 6.1g / m 2 The coating amount was coated on the polyepoxy oil layer cured in step (3) and dried at a temperature of 105°C for 5 minutes, that is, a high barrier paper-based packaging material was successfully prepared.

[0047] The performance of the high barrier paper-based packaging material prepared in this example was tested: Cobb120 was 0.89 g / m 2 , KIT oil resistance level is 12, oxygen permeability is 0.85 cm 3 / m2 24h 0.1Mpa, water vapor transmission rate is 71 g / m 2 The biodegradation rate after 24 hours (RH90%, 38℃) and 60 days is 84%.

[0048] Example 2

[0049] (1) Coating of starch layer:

[0050] The basis weight is 30g / m 2 The glossy side of the tissue paper is 0.7g / m 2 Apply gelatinized starch in a coating amount and dry it at room temperature. Be careful not to cause wrinkles and keep the paper surface flat.

[0051] (2) Coating of polyethylene layer:

[0052] Dissolve polyvinyl alcohol with a grade of 0599 in deionized water at a solid content of 15% and then add 6.0 g / m 2 Apply the coating amount on the starch layer dried in step (1), keep it flat, and dry it at room temperature;

[0053] (3) Coating of polyepoxy resin layer:

[0054] Add 30% dimethyl itaconate and 4% brand 1173 photoinitiator to epoxy soybean oil, place it in a heat-collecting constant temperature heating magnetic stirrer to fully mix and react, set the temperature to 85 ° C, the stirring speed to 400 rpm, the mixing time to 30 min, and after the end, the coating amount is 3.5 g / m 2 The coating amount is applied on the polyvinyl alcohol coating dried in step (2), and then irradiated under ultraviolet light for 1 second for curing;

[0055] (4) Coating of polyacrylic resin layer:

[0056] Pure acrylic emulsion was mixed with 6.3 g / m 2 The coating amount was coated on the polyepoxy oil layer cured in step (3) and dried at a temperature of 105 °C for 5 min, thereby successfully preparing a high barrier paper-based packaging material.

[0057] The performance of the high barrier paper-based packaging material prepared in this embodiment was tested: Cobb120 was 0.78 g / m 2 , KIT oil resistance level is 12, oxygen permeability is 0.83 cm 3 / m 2 24h 0.1Mpa, water vapor transmission rate is 65g / m 2 The biodegradation rate after 24 hours (RH90%, 38℃) and 60 days is 87%.

[0058] Example 3

[0059] (1) Coating of starch layer:

[0060] The basis weight is 30g / m 2 The glossy side of the tissue paper is 0.7g / m 2 Apply gelatinized starch in a coating amount and dry it at room temperature. Be careful not to cause wrinkles and keep the paper surface flat.

[0061] (2) Coating of polyethylene layer:

[0062] Polyvinyl alcohol with a grade of 0599 was dissolved in deionized water at a solid content of 15%, and then the mixture was heated to 6.0 g / m 2 Apply the coating amount on the starch layer dried in step (1), keep it flat, and dry it at room temperature;

[0063] (3) Coating of polyepoxy resin layer:

[0064] Add 30% 1,2-ethylene glycol dimethacrylate and 4% brand 1173 photoinitiator to epoxy soybean oil, place it in a heat-collecting constant temperature heating magnetic stirrer to fully mix and react, set the temperature to 85 ° C, the stirring speed to 400 rpm, and the stirring time to 30 min. After the end, the coating amount is 3.5 g / m 2 The coating amount is applied on the polyvinyl alcohol coating dried in step (2), and then irradiated under ultraviolet light for 1 second for curing;

[0065] (4) Coating of polyacrylic resin layer:

[0066] Pure acrylic emulsion was mixed with 10% triglyceride and dispersed using a heat-collecting constant temperature heating magnetic stirrer. The temperature was set to 65°C, the speed was 500 rpm, and the stirring time was 15 min. After fully stirring, the mixture was dispersed at a temperature of 6.3 g / m 2 The coating amount was coated on the polyepoxy oil layer cured in step (3) and dried at a temperature of 105°C for 5 minutes, thereby successfully preparing a high barrier paper-based packaging material.

[0067] The performance of the high barrier paper-based packaging material prepared in this example was tested: Cobb120 was 0.65 g / m 2 , KIT oil resistance level is 12, oxygen permeability is 0.82cm 3 / m 2 24h 0.1Mpa, water vapor transmission rate is 54 g / m 2 The biodegradation rate after 24 hours (RH90%, 38℃) and 60 days is 91%.

[0068] From the comparison between Example 1 and Example 2, it can be seen that using dimethyl itaconate or 1,2-ethylene glycol dimethacrylate instead of methyl acrylate can further reduce the water vapor transmission rate and improve the biodegradation rate.

[0069] From the comparison between Example 2 and Example 3, it can be seen that the addition of triglyceride to the pure acrylic emulsion can further improve the water and oil resistance, and at the same time, the biodegradation rate is also improved.

[0070] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A biodegradable high barrier paper-based packaging material, characterized in that: include: The base paper layer, starch layer, polyvinyl alcohol coating layer, polyepoxy oil resin layer, and polyacrylic acid resin layer are sequentially arranged from bottom to top; The coating amount ratio of the starch layer, the polyvinyl alcohol coating, the polyepoxy oil resin layer, and the polyacrylic acid resin layer is 0.5-1.5:5.5-7.5:3.5-3.7:6.1-6.5; The preparation method of the polyepoxy oil resin layer comprises: using 60% to 80% by mass of epoxy soybean oil acrylate, 20% to 40% by mass of acrylate monomer, and 2% to 4% by mass of photoinitiator, the sum of the amounts of each component being 100%, and initiating polymerization to obtain the obtained product; The acrylic acid ester monomer is selected from one or more of methyl acrylate, butyl acrylate, isooctyl acrylate, dimethyl itaconate, 1,4-butanediol diacrylate, and 1,2-ethylene glycol dimethacrylate; The polyacrylic resin layer is an aqueous acrylic resin emulsion, or an aqueous acrylic resin emulsion dispersed with 1 wt % to 10 wt % of stearic acid glyceryl, vegetable oil triglyceride, neopentyl glycol dioleate, trimethylolpropane trioleate, epoxy soybean oil or triglycerol.

2. The biodegradable high barrier paper-based packaging material according to claim 1, characterized in that: The material used for the starch layer is natural starch or modified starch; The natural starch includes: potato starch, bean starch, cereal starch, and vegetable starch; The modified starch includes: anionic starch, cationic starch, amphoteric and multi-modified starch, and nonionic starch.

3. The biodegradable high barrier paper-based packaging material according to claim 1, characterized in that: The material used for the polyvinyl alcohol coating is polyvinyl alcohol.

4. A method for preparing the biodegradable high-barrier paper-based packaging material according to any one of claims 1 to 3, characterized in that: include: The starch is gelatinized and evenly coated on the surface of the base paper and dried to obtain a starch layer; dissolving polyvinyl alcohol and coating it on the starch layer, and drying to obtain a polyvinyl alcohol coating; The epoxy soybean oil acrylate, acrylates, and photoinitiator are uniformly mixed to obtain a mixed solution; coating the mixed solution on the polyvinyl alcohol coating and light curing the mixture to obtain a polyepoxy oil resin layer; A water-based acrylic resin emulsion is coated on the polyepoxy oil resin layer and dried to obtain a polyacrylic resin layer.

5. The method for preparing the biodegradable high-barrier paper-based packaging material according to claim 4, characterized in that: The photoinitiator is a cationic initiator.

6. The method for preparing the biodegradable high-barrier paper-based packaging material according to claim 4, wherein: The curing time under ultraviolet light is 0.5s to 1s.