Pulp composition, paper-plastic packaging container and preparation method thereof

Abstract

The technical solution of the present invention is as follows: a pulp composition, a paper-plastic packaging container and a preparation method thereof, including the following steps and components: S1. Perform a first pulping process on the first pulp and store it as a first solution, wherein a waterproofing agent and a sizing agent are added in the first pulping process; S2. Perform a second pulping process on the second pulp and store it as a second solution, wherein a demolding agent and a reinforcing agent are added in the second pulping process; S3. Mix the first solution and the second solution and add a wet strength agent to obtain a pulp composition; S4. Complete a paper-plastic forming process based on the pulp composition to obtain a paper-plastic packaging container. The production process flow is simplified, the investment in manpower and equipment is saved, and products with uniform waterproof performance and stable performance at each position can be prepared; it also avoids the pollution to the environment caused by the non-degradability of surface-coated products such as PP and PE in nature.

Description

Technical Field

[0001] The invention relates to the technical field of waterproof paper-plastics, and in particular to a pulp composition, a paper-plastics packaging container and a preparation method thereof. Background Art

[0002] Pulp molding products are made of one or more combinations of waste paper, bamboo pulp, sugarcane pulp, wood pulp fiber, etc. as raw materials. They are made of loose pulp, pulp grinding, pulp mixing, vacuum suction filtration, wet embryos, and then hot-pressed to form finished products. No adhesive is required in the production process of this product. It is formed only by the interaction between the fibers themselves and the structure of the mold itself. It can manufacture various paper products with complex shapes and structures and high dimensional accuracy requirements, and it is environmentally friendly and biodegradable.

[0003] After being placed for a long time, paper and plastic packaging containers will absorb moisture in the air, resulting in reduced strength and deformation, which will affect their use. Especially in packaging containers for products such as alcoholic beverages that need to be placed for a long time or are placed in an environment with poor dryness and ventilation, it is necessary to have a high waterproof property to prevent the paper and plastic packaging containers from absorbing moisture and causing their own strength to decrease, or the collapse of the overall packaging caused by the leakage of the liquid of the packaged product. In order to solve the above problems, the traditional method is usually to immerse or spray waterproof agents on paper and plastic packaging containers, or to coat the surface of the products to increase their waterproof properties. However, in actual use, the structures of many paper and plastic packaging containers are relatively complex, especially at the corners and bends of paper and plastic packaging containers. Dipping or spraying has high process control difficulties and high investment costs. The uniformity of the waterproof agent film cannot be controlled, resulting in inconsistent waterproof levels. The use of surface coating technology not only reduces the biodegradability of the product, but also has the problem that the facades and corners cannot be effectively coated.

[0004] For example, the traditional surface spraying process of silicone, liquid paraffin, etc. is complicated, and requires more manpower and equipment. In addition, the corners, facades, and internal platforms in the three-dimensional spraying process cannot be effectively sprayed, resulting in differences in overall waterproofness and leakage in some locations. Products using traditional PP, PE, etc. surface coatings cannot effectively coat the facades and corners of the products, and the process is complicated and the investment cost is high. In addition, plastic products such as PP and PE cannot be naturally degraded in nature, which will cause pollution to the environment. Therefore, how to improve the strength and waterproof performance of paper-plastic packaging containers is a problem that technicians in this field should consider. Summary of the invention

[0005] The object of the present invention is to provide a pulp composition, a paper-plastic packaging container and a preparation method thereof. During the pulping process, a sizing agent, a wet strength agent, a release agent, a waterproof agent and a reinforcing agent are introduced and added to each process of producing the paper-plastic packaging container according to different proportions and sequences to prepare a waterproof pulp. Through processes such as vacuum suction forming by a molding machine die, extrusion dehydration, and heating and drying, a paper-plastic packaging container with high strength and high waterproofness is prepared. It is used for packaging products with requirements for waterproof level and strength, expanding the application range of existing paper-plastic packaging containers which are limited in use due to insufficient waterproof performance and strength or inability to balance both.

[0006] The technical solution of the present invention is: a pulp composition, comprising the following components:

[0007] Fiber pulp;

[0008] Calculated by percentage of the mass of the fiber pulp:

[0009] 2 - 5% of sizing agent;

[0010] 1 - 4% of waterproof agent;

[0011] 3 - 6% of reinforcing agent;

[0012] 1 - 5% of wet strength agent;

[0013] 2 - 4% of release agent.

[0014] Preferably, the fiber pulp is the first pulp with a negatively charged surface and a fiber length of 1 - 2 mm and / or the second pulp with a fiber length of 1 - 1.5 mm;

[0015] The waterproof agent is an aqueous solution of water-soluble stearic acid and / or an aqueous solution of water-soluble stearate;

[0016] The reinforcing agent is acrylic emulsion and / or modified acrylic emulsion;

[0017] The release agent is an organosilicon waterproof release agent.

[0018] Preferably, the fiber pulp comprises 35 parts by mass of sugarcane pulp and 65 parts by mass of bamboo pulp;

[0019] 2 - 5 parts by mass of the sizing agent;

[0020] 1 - 2 parts by mass of the wet strength agent;

[0021] 1 - 4 parts by mass of the water-soluble stearic acid and / or water-soluble stearate;

[0022] 3 - 6 parts by mass of the acrylic emulsion and / or modified acrylic emulsion;

[0023] The silicone waterproof release agent is 2-4 parts by mass.

[0024] In the present invention, by virtue of the different viscosities, surface charges and functions of various additives, and adopting specific addition amounts, addition sequences and processes, various additives are efficiently mixed with fibers and with each other or react with each other to achieve the quality effects of paper-plastic waterproofing and high strength. At the same time, it avoids the disadvantages of uneven waterproofness and non-biodegradability of traditional paper-plastic products.

[0025] A preparation method of a paper-plastic packaging container comprises the following steps:

[0026] S1. Conduct a first pulping process on the first slurry and store it as a first solution. Among them, a waterproofing agent and a sizing agent are added in the first pulping process;

[0027] S2. Conduct a second pulping process on the second slurry and store it as a second solution. Among them, a release agent and a reinforcing agent are added in the second pulping process;

[0028] S3. Mix the first solution and the second solution and add a wet strength agent to obtain a pulp composition;

[0029] S4. Complete a paper-plastic forming process based on the pulp composition to obtain a paper-plastic packaging container.

[0030] Preferably, when preparing the first solution, water and a waterproofing agent are added in sequence, and after stirring evenly, the first slurry is loosened; then grinding and adding a sizing agent are carried out in sequence.

[0031] Preferably, before adding the waterproofing agent, it is diluted 20-40 times; before adding the sizing agent, it is diluted 30-50 times.

[0032] In the present invention, a waterproofing agent with a negatively charged surface is used, which is mutually exclusive with the first slurry with a negatively charged surface and is more likely to form a uniform whole; after grinding, more free anionic groups appear on the surface of the first slurry fibers, and then a sizing agent with a positively charged surface is added. Taking the sizing agent as a bridge, the first slurry fibers and the waterproofing agent are connected to each other.

[0033] Preferably, when preparing the second solution, water, a release agent and a reinforcing agent are added in sequence, and after stirring evenly, the second slurry is loosened.

[0034] Preferably, before adding the release agent, it is diluted 20-40 times; before adding the reinforcing agent, it is diluted 20-40 times; and after adding the release agent, it is stirred evenly and then the reinforcing agent is added.

[0035] In the present invention, the release agent is non-ionic, and both the reinforcing agent and the surface of the second slurry fibers are negatively charged, and they repel each other to form a uniform whole after stirring.

[0036] Preferably, the wet strength agent is added after the first solution and the second solution are uniformly mixed; and before the addition of the wet strength agent, it is diluted 30 - 50 times.

[0037] In the present invention, the wet strength agent has a positive charge on its surface, further playing a bridging role to enhance the connection between the waterproofing agent and the strengthening aid and the fiber pulp, so that all anionic and cationic aids can be adsorbed on the fiber surface.

[0038] A paper-plastic packaging container is prepared based on the above-mentioned pulp composition or prepared according to the above-mentioned preparation method.

[0039] Compared with the prior art, the advantages of the present invention are:

[0040] (1) Compared with the traditional surface spraying processes using silicone, liquid paraffin, etc., the production process flow is simplified, the input of labor and equipment is saved, and the problems of ineffective spraying on the corners, vertical surfaces, internal platforms and other parts in the three-dimensional spraying process, resulting in differences in the overall waterproof performance and liquid leakage at some positions, are avoided. A packaging container product with uniform waterproof performance and stable performance at each position can be prepared.

[0041] (2) Compared with the traditional products with surface coating of PP, PE, etc., the production process is simplified, the input of labor and equipment is saved, and the pollution to the environment caused by the non-degradability of PP, PE and other plastic products in nature is also avoided, realizing the production and manufacturing of truly pollution-free, biodegradable, highly waterproof and high-strength paper-plastic products.

[0042] (3) Using an organosilicon waterproof release agent, an aqueous solution of stearic acid and / or an aqueous solution of stearate to prepare a suspension solution of spherical particles with a particle size of 20 - 30 μm. During the formation of the wet embryo, it fills the voids between the fibers; during the heating and dehydration process of the wet embryo, the particles melt and partially migrate to the product surface along with the water vapor. After the product cools, a layer of stearic acid or organosilicon water-resistant coating condenses again on the inside and surface of the product, endowing the product with excellent waterproof performance.

[0043] (4) Using acrylic emulsion and / or modified acrylic emulsion mainly improves the problem of the decrease in product strength caused by the use of organosilicon waterproof release agent, stearic acid and / or stearate.

[0044] (5) The internal sizing agent can adhere to the fiber surface. After the heating process, it melts and migrates to coat the fiber surface. By changing the fiber surface tension, it prevents the penetration of moisture into the fiber interior, playing a role in reducing and delaying the penetration of moisture into the fiber interior. Moreover, the sizing agent shows a positive charge and acts as a bridge to connect the fiber and the water-based stearic acid and / or water-based stearate. Through the attraction between positive and negative charges, the three are connected as a whole, and to a certain extent, the strength of the paper-plastic product is also increased.

[0045] (6) A wet strength agent with a positive charge is used to further play the role of a bridge for further combination of the anionic water-based stearic acid and / or water-based stearate and acrylic emulsion and / or modified acrylic emulsion existing in the system, so that all anionic and cationic additives can be adsorbed on the fiber surface. After heating, a three-dimensional cross-linked network structure is formed, enhancing the overall waterproofness and strength. Brief Description of the Drawings

[0046] The present invention will be further described below in conjunction with the drawings and embodiments:

[0047] Figure 1 It is the process flow chart for the preparation of the paper-plastic packaging container described in the present invention;

[0048] Figure 2 It is the process flow chart for the preparation technology of the paper-plastic packaging container described in the present invention. Detailed Embodiments

[0049] The following will further elaborate on the content of the present invention in conjunction with specific embodiments. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0050] In this embodiment, the release agent is an organosilicon waterproof release agent, which is non-ionic. The THIF-720 release agent of Hengxin Chemical Technology Co., Ltd. or the Dow Corning MEM-1728 organosilicon release agent can be used; the waterproof agent is a water-based stearic acid and / or water-based stearate with a negative charge on the surface. The ye3661 water-based stearic acid emulsion or yf6633 zinc stearate emulsion of Luoyang Yefang New Material Technology Co., Ltd. can be selected; the strengthening agent is an acrylic emulsion and / or modified acrylic emulsion with a negative charge on the surface. The XQ-70 strengthening agent of Taishan Xinquan Paper-making Additive Factory or the PCG-G20 dry strength agent of Suzhou Paikaimu New Energy Technology Co., Ltd. can be selected.

[0051] As Figure 2 shown, a method for preparing a paper-plastic packaging container includes the following steps:

[0052] S1. Perform the first pulping process on the first slurry and store it as the first solution. In the first pulping process, a waterproofing agent and a sizing agent are added.

[0053] The defibering of the first slurry is carried out in a defibering device. First, water is added, and then a water-based stearic acid and / or water-based stearate with a mass ratio of 1 - 4% and diluted 20 - 40 times is added. Generally, it is stirred for 5 - 15 minutes. After stirring evenly, pulp sheets are added for the defibering of the first slurry. First of all, after dilution, the water-based stearic acid and / or water-based stearate form a suspension solution of spherical particles with a diameter of 20 - 30 μm and are easily filled in the gaps of bamboo fibers after stirring. Further, the water-based stearic acid and / or water-based stearate is an anionic additive, and its surface carries a negative charge, which can repel and mix more evenly with the first slurry fibers with a negative charge on the surface. The refining is carried out in a refiner. After refining, a sizing agent with a mass ratio of 2 - 5% and diluted 30 - 50 times is added. After refining, more free anionic groups appear on the surface of the first slurry fibers. The sizing agent carries a positive charge and is a cationic additive, and it is connected to the first slurry fibers, the water-based stearic acid and / or water-based stearate at the same time, making the three connect into a whole.

[0054] S2. Perform the second pulping process on the second slurry and store it as the second solution. In the second pulping process, a demolding agent and a reinforcing agent are added.

[0055] In the defibering process of the second slurry, first, white water is added, and then an organosilicon waterproof demolding agent with a mass ratio of 2 - 4% and diluted 20 - 40 times is added. After stirring evenly for 5 - 15 minutes, an acrylic emulsion and / or modified acrylic emulsion with a mass ratio of 3 - 6% and diluted 20 - 40 times is added, and it is stirred for 5 - 15 minutes. After mixing evenly, pulp sheets are added for defibering. The acrylic emulsion and / or modified acrylic emulsion is a non-ionic type product. After dilution, it is prepared into a suspension solution of spherical particles with a diameter of 20 - 30 μm and is easily filled evenly in the gaps of the second slurry fibers after stirring. The acrylic emulsion and / or modified acrylic emulsion is an anionic additive, and its surface carries a negative charge. The surface of the second slurry fibers also carries a negative charge, and they are also easily mixed evenly with each other due to mutual repulsion after stirring. At this time, the second solution as a whole presents a negative charge.

[0056] S3. Mix the first solution and the second solution and add a wet strength agent to obtain a pulp composition.

[0057] Among them, a wet strength agent diluted 30 - 50 times with a mass ratio of 1 - 5% is added after mixing. After the action of the waterproofing agent in the pulp storage barrel in the early stage, there are some negative charges on the fiber surface, and some anionic additives have been adsorbed onto the fiber surface. After mixing, they become an integral whole, and then a cationic wet strength agent is added, which further serves as a bridge to adsorb the anionic aqueous stearic acid and / or aqueous stearate, acrylic emulsion, and / or modified acrylic emulsion present in the pulp composition. This enables all anionic and cationic additives to be adsorbed on the fiber surface.

[0058] S4. Complete the paper - plastic forming process based on the pulp composition to obtain a paper - plastic packaging container.

[0059] The pulp composition is first diluted, and then heated in a forming machine to form a network structure with spatially staggered connections. At the same time, the aqueous stearic acid and / or aqueous stearate, which act as waterproofing additives, melt at high temperatures. As the water evaporates, part of them migrates to the surface of the product and forms a uniform and dense waterproof film after cooling. Through the action of the additives on the surface and inside, the overall waterproofness of the product meets the usage requirements.

[0060] It should be noted that the above - mentioned "mass ratio" is calculated based on the mass of the dry pulp of the fiber slurry and has nothing to do with the amount of added water. Both the first pulp fiber and the second pulp fiber carry negative charges on their surfaces. First, adding negatively charged or non - ionic additives, such as aqueous stearic acid and / or aqueous stearate, silicone waterproof release agent, and acrylic emulsion and / or modified acrylic emulsion, can ensure more uniform mixing; then adding positively charged additives, such as sizing agents and wet strength agents, which play a bridging role through cationic additives, can promote the tight connection between anionic additives, fibers, and themselves.

[0061] It should be noted that the various additives used in the high - strength and stable waterproof paper - plastic products in this application are not simply additive in terms of performance. Particularly crucial is the addition sequence and dosage of various additives. Due to differences in the viscosity, surface charge, and functions of various additives, various additives need to be added separately and in the addition sequence as described in the above steps. Otherwise, various additives in the entire system will not be able to combine efficiently or deposit efficiently on the fiber surface, resulting in weakened effects of some additives and their loss with white water, failing to achieve the desired effects.

[0062] It should be noted that the fiber slurry uses fibers with a negatively charged surface, and is divided into a first slurry and a second slurry according to the fiber length. Initially, it is in the state of dry pulp board. The second slurry is short fibers about 1 - 1.5 mm in length, with a mass ratio of 35%, preferably sugarcane pulp; the first slurry is medium - long fibers of 1 - 2 mm, with a mass ratio of 65%, preferably bamboo pulp. It should be noted that through experiments, it is proved that in the process of this application, using sugarcane pulp and bamboo pulp as fiber slurries can achieve better strength performance, but it does not mean that bamboo pulp and sugarcane pulp are the only choices for fiber slurries. For example, bamboo pulp can be replaced by medium - long fiber wood pulp, and sugarcane pulp can be replaced by short fiber straw pulp, reed pulp, etc.

[0063] In actual production, generally the production batch is large. To ensure the output and production continuity, operations such as continuous defibering, refining, mixing, and forming need to be carried out. Therefore, corresponding storage barrels will be added for temporary storage after each step. For example, a post - defibering storage barrel is set after the defibering process. After the first slurry and the second slurry are defibered, they will be temporarily stored in the corresponding post - defibering storage barrels; a post - refining storage barrel is set after the refining process. After the first slurry is refined, it will be transferred to the post - refining storage barrel for temporary storage; after mixing in the mixing tank, a post - mixing storage barrel is set. After the first solution and the second solution are mixed, they are transferred to the post - mixing storage barrel for storage; during the process from the mixed liquid to the forming machine, dilution is required, and after dilution, it is transferred through the corresponding containers. Therefore, multiple dilution barrels and pulp supply barrels, etc., will also be set.

[0064] The following is combined with the attached Figure 1 , and the present invention will be described in detail through specific embodiments. Among them, for the convenience of description and using the optimal additives, the first slurry is bamboo pulp, the second slurry is sugarcane pulp, the waterproof agent is water - based stearic acid, and the strengthening agent is modified acrylic emulsion for specific description. Embodiment

[0065] (1) Add white water to the defibering machine, then add water - based stearic acid with a mass ratio of 1% and diluted 30 times, and stir for 5 min; then add bamboo pulp board with a mass ratio of 65% for defibering. After defibering, it is stored in the bamboo pulp post - defibering storage barrel; then it is transferred to the refining machine for refining. After refining, it is stored in the post - refining storage barrel, and a sizing agent with a mass ratio of 2% and diluted 40 times is added. At this time, it is the first solution;

[0066] (2) Add white water to the defibering machine, then add silicone waterproof release agent with a mass ratio of 2% and diluted 30 times, and stir for 5 min; then add modified acrylic emulsion with a mass ratio of 3% and diluted 30 times, and stir again for 5 min; then add sugarcane pulp board with a mass ratio of 35% for defibering. After defibering, it is stored in the storage barrel. This is the second solution;

[0067] (3) Transfer the above-mentioned first solution and second solution to a mixing barrel for mixing, then add a wet strength agent with a mass ratio of 2% and diluted 40 times, and stir for 5 minutes. This is the pulp composition;

[0068] (4) Further dilute the pulp composition, and then transfer it to a pulp supply barrel and a forming machine in sequence for paper-plastic forming to obtain the final paper-plastic product A1. Example

[0069] (1) Add white water to a pulper, then add an aqueous stearic acid with a mass ratio of 2% and diluted 30 times, and stir for 5 minutes; then add bamboo pulp sheets with a mass ratio of 65% for pulping, and store the pulp in a bamboo pulp storage barrel after pulping; then transfer it to a refiner for refining, store the refined pulp in a post-refining storage barrel, and add a sizing agent with a mass ratio of 3% and diluted 40 times. This is the first solution;

[0070] (2) Add white water to a pulper, then add an organosilicon waterproof release agent with a mass ratio of 3% and diluted 30 times, and stir for 5 minutes; then add a modified acrylic emulsion with a mass ratio of 4% and diluted 30 times, and stir again for 5 minutes; then add sugarcane pulp sheets with a mass ratio of 35% for pulping, and store the pulp in a storage barrel after pulping. This is the second solution;

[0071] (3) Transfer the above-mentioned first solution and second solution to a mixing barrel for mixing, then add a wet strength agent with a mass ratio of 2% and diluted 40 times, and stir for 5 minutes. This is the pulp composition.

[0072] (4) Further dilute the pulp composition, and then transfer it to a pulp supply barrel and a forming machine in sequence for paper-plastic forming to obtain the final paper-plastic product A2. Example

[0073] (1) Add white water to a pulper, then add an aqueous stearic acid with a mass ratio of 3% and diluted 30 times, and stir for 5 minutes; then add bamboo pulp sheets with a mass ratio of 65% for pulping, and store the pulp in a bamboo pulp storage barrel after pulping; then transfer it to a refiner for refining, store the refined pulp in a post-refining storage barrel, and add a sizing agent with a mass ratio of 3% and diluted 40 times. This is the first solution;

[0074] (2) Add white water to a pulper, then add an organosilicon waterproof release agent with a mass ratio of 3% and diluted 30 times, and stir for 5 minutes; then add a modified acrylic emulsion with a mass ratio of 5% and diluted 30 times, and stir again for 5 minutes; then add sugarcane pulp sheets with a mass ratio of 35% for pulping, and store the pulp in a storage barrel after pulping. This is the second solution;

[0075] (3) Transfer the above-mentioned first solution and second solution to a mixing bucket for mixing, then add a wet strength agent with a mass ratio of 2% and diluted 40 times, and stir for 5 minutes to obtain the pulp composition;

[0076] (4) Further dilute the pulp composition, and then transfer it to a pulp supply bucket and a forming machine in sequence for paper-plastic forming to obtain the final paper-plastic product finished product A3. Example

[0077] (1) Add white water to a disintegrator, then add an aqueous stearic acid with a mass ratio of 4% and diluted 30 times, and stir for 5 minutes; then add bamboo pulp sheets with a mass ratio of 65% for disintegration. After disintegration, store it in a bamboo pulp disintegration storage bucket; then transfer it to a refiner for refining. After refining, store it in a post-refining storage bucket, and add a sizing agent with a mass ratio of 3.4% and diluted 40 times. This is the first solution;

[0078] (2) Add white water to a disintegrator, then add an organosilicon waterproof demolding agent with a mass ratio of 3.5% and diluted 30 times, and stir for 5 minutes; then add a modified acrylic emulsion with a mass ratio of 2.5% and diluted 30 times, and stir again for 5 minutes; then add sugarcane pulp sheets with a mass ratio of 35% for disintegration. After disintegration, store it in a storage bucket. This is the second solution;

[0079] (3) Transfer the above-mentioned first solution and second solution to a mixing bucket for mixing, then add a wet strength agent with a mass ratio of 3% and diluted 40 times, and stir for 5 minutes to obtain the pulp composition;

[0080] (4) Further dilute the pulp composition, and then transfer it to a pulp supply bucket and a forming machine in sequence for paper-plastic forming to obtain the final paper-plastic product finished product A4.

[0081] Comparative Example 1

[0082] (1) Add white water to a disintegrator, then add bamboo pulp sheets with a mass ratio of 65% for disintegration. After disintegration, store it in a bamboo pulp disintegration storage bucket; then transfer it to a refiner for refining. After refining, store it in a post-refining storage bucket, and add a sizing agent with a mass ratio of 4% and diluted 40 times. This is the first solution;

[0083] (2) Add white water to a disintegrator, then add sugarcane pulp sheets with a mass ratio of 35% for disintegration. After disintegration, store it in a storage bucket. This is the second solution;

[0084] (3) Transfer the above-mentioned first solution and second solution to a mixing bucket for mixing, then add a wet strength agent with a mass ratio of 1% and diluted 40 times, and stir for 5 minutes to obtain the pulp composition;

[0085] (4) Further dilute the pulp composition, and then transfer it to the pulp supply tank and the forming machine in sequence for paper-plastic forming to obtain the final finished paper-plastic product D1.

[0086] Comparative Example 2

[0087] (1) Add white water to the pulper, and then add bamboo pulp board with a mass ratio of 65% for pulping. After pulping, store it in the bamboo pulp storage tank; then transfer it to the refiner for refining. After refining, store it in the post-refining storage tank, and add a sizing agent with a mass ratio of 5% and diluted 40 times. At this time, it is the first solution;

[0088] (2) Add white water to the pulper, and then add sugarcane pulp board with a mass ratio of 35% for pulping. After pulping, store it in the storage tank. This is the second solution;

[0089] (3) Transfer the above first solution and second solution to the mixing tank for mixing, and then add a wet strength agent with a mass ratio of 1% and diluted 40 times, and stir for 5 min. This is the pulp composition;

[0090] (4) Further dilute the pulp composition, and then transfer it to the pulp supply tank and the forming machine in sequence for paper-plastic forming to obtain the final finished paper-plastic product D2.

[0091] For the products A1, A2, A3, A4, and A5 in the above five examples, the strength and waterproofness are respectively detected, as shown in Table 1 below:

[0092]

[0093] In Table 1, the tensile strength, burst strength, and interlayer bonding strength are all indicators of paper-plastic strength, and the waterproofness is an index of waterproof performance. The density and thickness are all actual production data of the tested paper-plastic products. Among the five groups of examples, the density is 0.6 - 0.67 g / cm 3 ³, and the thickness is 0.91 - 0.99 mm, both within the qualified range. Therefore, it can be considered that the product specifications of the paper-plastic packaging containers produced in the above five examples meet the requirements, and the slight differences in their dimensions do not affect the strength and waterproofness test results and can be used for comparison as the same type.

[0094] It should be noted that the above embodiments are those of water-based stearic acid at mass ratios of 0%, 1%, 2%, 3%, and 4% respectively, with other additives at their optimal addition amounts. For example, when the mass ratio of water-based stearic acid is 1%, there are multiple choices for the addition amounts of other additives. The ratio of the additives disclosed in the above Embodiment 1 is the optimal ratio obtained after a large number of experiments when the mass ratio of water-based stearic acid is 1%, rather than the only ratio option. Additionally, in Comparative Examples 1 and 2, the mass ratio of water-based stearic acid is 0% for the purpose of comparison to explain the embodiments of the present invention and is not prior art.

[0095] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple deformations can be made to the technical solutions of the present invention. For example, during pulping, the corresponding dry pulp sheets can be added first, and water-based stearic acid can be added during pulping; the sizing agent can be added while grinding the pulp; the order of adding the silicone waterproof release agent and the acrylic emulsion can also be adjusted, etc. Although it has been proven through actual tests that such adjustments to the addition order of the additives will result in a decrease in the waterproof performance or strength of the formed paper-plastic products, such simple deformations all fall within the protection scope of the present invention. Those skilled in the art should understand that the above embodiments and the description in the specification only illustrate the principle of the present invention, and the scope of protection required by the present invention is defined by the appended claims and their equivalents.

[0096] It should be noted that the raw materials for paper-plastic packaging container products are not only bamboo pulp and sugarcane pulp, but can also be waste paper, wood pulp, etc. Moreover, in addition to pulping, grinding, pulp blending, and hot pressing for forming, its production processes also include vacuum filtration forming, wet embryo forming, etc. To avoid excessive details unrelated to the present invention, the present invention will not be specifically described.

[0097] The above embodiments are only for explaining the technical concept and characteristics of the present invention, and their purpose is to enable those familiar with this technology to understand the content of the present invention and implement it accordingly, and cannot be used to limit the protection scope of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention.

Claims

1. A preparation method of a paper-plastic packaging container, characterized in that, the pulp for paper-plastic use comprises the following components: Fiber pulp; Calculated by the mass percentage of the fiber pulp: Sizing agent 2-5%; Waterproof agent 1-4%; Reinforcing agent 3-6%; Wet strength agent 1-5%; Release agent 2-4%; The preparation method of the paper-plastic packaging container comprises the following steps: S1. Conduct a first pulping process on the first pulp and store it as the first solution, wherein, a waterproof agent and a sizing agent are added in the first pulping process; S2. Conduct a second pulping process on the second pulp and store it as the second solution, wherein, a release agent and a reinforcing agent are added in the second pulping process; S3. Mix the first solution and the second solution and add a wet strength agent to obtain a pulp composition; S4. Complete the paper-plastic forming process based on the pulp composition to obtain the paper-plastic packaging container; The fiber pulp is the first pulp with a negatively charged surface and a fiber length of 1-2 mm and / or the second pulp with a fiber length of 1-1.5 mm; The waterproof agent is an aqueous solution of water-soluble stearic acid and / or an aqueous solution of water-soluble stearate; The reinforcing agent is acrylic emulsion and / or modified acrylic emulsion; The release agent is an organosilicon waterproof release agent.

2. The preparation method of the paper-plastic packaging container according to claim 1, characterized in that: The fiber pulp comprises 35 parts by mass of sugarcane pulp and 65 parts by mass of bamboo pulp; The sizing agent is 2-5 parts by mass; The wet strength agent is 1-2 parts by mass; The water-soluble stearic acid and / or water-soluble stearate is 1-4 parts by mass; The acrylic emulsion and / or modified acrylic emulsion is 3-6 parts by mass; The organosilicon waterproof release agent is 2-4 parts by mass.

3. The preparation method of the paper-plastic packaging container according to claim 1, characterized in that: When preparing the first solution, water and a waterproof agent are added in sequence, stirred evenly and then the first pulp is loosened; then refining and adding a sizing agent are carried out in sequence.

4. The preparation method of the paper-plastic packaging container according to claim 1, characterized in that: Before adding the waterproof agent, it is diluted 20-40 times; before adding the sizing agent, it is diluted 30-50 times.

5. The preparation method of the paper-plastic packaging container according to claim 1, characterized in that: When preparing the second solution, water, a release agent and a reinforcing agent are added in sequence, stirred evenly and then the second pulp is loosened.

6. The preparation method of the paper-plastic packaging container according to claim 1, characterized in that: Before adding the release agent, it is diluted 20-40 times; before adding the reinforcing agent, it is diluted 20-40 times; and after adding the release agent, it is stirred evenly and then the reinforcing agent is added.

7. The preparation method of the paper-plastic packaging container according to claim 1, characterized in that: The wet strength agent is added after the first solution and the second solution are evenly mixed; and before adding the wet strength agent, it is diluted 30-50 times.

8. A paper-plastic packaging container, characterized in that, it is prepared based on the pulp composition described in any one of claims 1 to 2, or prepared according to the method described in any one of claims 3 to 7.

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