Preparation method of paper-plastic product and paper pulp molded ice cream stick

Abstract

The invention provides a preparation method of a paper-plastic product and a paper pulp molded ice cream stick. The preparation method comprises the following steps: S1) obtaining a wet blank of the paper-plastic product through a pulping process and a blank making process; s2) spraying a water-based waterproof coating on the surface of the wet blank to form a water-based waterproof coating; (S3) carrying out hot-pressing shaping on the wet blank with the water-based waterproof coating obtained in the step (S2) to obtain a to-be-processed product; and S4) contacting the surface of the to-be-processed product with a wax material to form a wax layer on the surface of the to-be-processed product so as to prepare the paper-plastic product. According to the method, hot-pressing shaping is performed after the waterproof coating is sprayed, the waterproof coating layer cannot be sticky in the hot-pressing shaping process, the independent drying procedure is omitted, and the problem that a paper-plastic product is prone to deformation due to the fact that the paper-plastic product is sprayed with the water-based coating and then dried is solved. The spraying of the waterproof coating plays a role in preventing water on the surface of the product and pressing lint, and the use of the biological wax strengthens the waterproof performance, expels moisture in the fibers and increases the stiffness.

Description

Technical Field

[0001] The invention relates to the technical field of food, and in particular to a method for preparing a paper-plastic product and a pulp-molded ice cream stick. Background Art

[0002] With the continuous improvement of environmental protection requirements, new pulp molded ice cream sticks have appeared on the market. Paper ice cream sticks are made by crushing fiber slurry and hot pressing to shape it. Compared with traditional wooden and plastic ice cream sticks, paper ice cream sticks are more environmentally friendly. However, they have the disadvantages of poor stiffness, moisture resistance and easy paper hair on the surface, which greatly affects the user experience.

[0003] At present, the industry has improved the above-mentioned problem by adding waterproof and oil-proof agents into the pulp molding slurry and spraying waterproof coating on the surface of the popsicle stick. However, the prepared popsicle stick still has many fine paper fibers and is easy to absorb water and deform.

[0004] How to solve the above problems to improve consumers' experience is an urgent problem to be solved in pulp molded ice cream sticks. Summary of the invention

[0005] In view of the above technical problems, the present invention provides a method for preparing a paper-plastic product and a pulp molded ice cream stick. The prepared ice cream stick is made of pulp molded material, has the characteristics of not easily absorbing water and deforming and having a smooth surface.

[0006] In order to solve the above technical problems, the present invention provides a method for preparing a paper-plastic product, comprising the following steps:

[0007] S1) obtaining wet embryos of paper-plastic products through pulping and embryo copying processes;

[0008] S2) spraying a water-based waterproof coating on the surface of the wet embryo to form a water-based waterproof coating;

[0009] S3) hot pressing and shaping the wet embryo with the water-based waterproof coating obtained in S2) to obtain a product to be processed;

[0010] S4) contacting the surface of the product to be processed with a wax material to form a wax layer on the surface of the product to be processed, so as to prepare the paper-plastic product.

[0011] Optionally, the water-based waterproof coating is a food-grade environmentally friendly water-based waterproof coating, and the food-grade environmentally friendly water-based waterproof coating is an oil-in-water emulsion formed by an aqueous phase material and an oil phase material;

[0012] The waxy material is a food grade waxy material.

[0013] Optionally, the S1) includes: performing the pulping process and the embryo copying process based on non-wood fiber materials to obtain the wet embryo of the paper-plastic product, wherein the non-wood fiber material includes one or more of bamboo and sedge.

[0014] Optionally, the aqueous phase material is selected from natural polysaccharides;

[0015] The oil phase material is selected from one or more of rosin, wax, shellac and AKD.

[0016] Optionally, the spraying amount of the food-grade environmentally friendly water-based waterproof coating is 3-5g / m 2 .

[0017] Optionally, the moisture content of the wet embryo is 68%-73%.

[0018] Optionally, the hot pressing and shaping is performed using a hot pressing and shaping machine;

[0019] The upper mold temperature of the thermoforming machine is 140-160°C, and the lower mold temperature is 120-140°C;

[0020] The oil cylinder pressure is 50-100 tons;

[0021] The setting time is 60-90s.

[0022] The invention provides a pulp molded ice cream stick, comprising a paper-plastic product obtained based on the preparation method.

[0023] Optionally, the pulp molded ice cream stick includes a non-wood fiber layer, a water-based coating layer compounded on the surface of the non-wood fiber layer, and a wax layer compounded on the water-based coating layer.

[0024] Optionally, the thickness of the water-based coating layer is 0.5-2 μm; and / or,

[0025] The thickness of the non-wood fiber layer is 1.8-2 mm.

[0026] Optionally, the wax layer has a thickness of 2 to 10 μm.

[0027] The present invention uses water-based waterproof coating to spray the wet embryo surface of paper and plastic products, and performs hot pressing and shaping after spraying the waterproof coating. The waterproof coating layer will not become sticky during the hot pressing and shaping process, and a separate drying process is omitted, and the problem that the paper and plastic products are easily deformed due to spraying the water-based coating and then drying is avoided. Secondly, the spraying of the waterproof coating plays a role in waterproofing the surface of the product and suppressing paper hair, and the use of bio-wax further consolidates the waterproof performance, and also drives away the moisture in the fiber, thereby increasing the stiffness of the product. The paper and plastic products finally prepared have the characteristics of not being easy to absorb water and deform and having a smooth surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings herein are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present invention, and together with the specification are used to explain the principles of the present invention. In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the description of the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor.

[0029] Figure 1 A schematic diagram of the structure of a pulp molded ice cream stick provided by the present invention;

[0030] Figure 2 This is a schematic diagram of the product appearance of the pulp molded ice cream stick provided by the present invention.

[0031] The realization of the purpose, functional features and advantages of the present invention will be further described in conjunction with the embodiments and with reference to the accompanying drawings. Through the above-mentioned drawings, clear embodiments of the present invention have been shown, and more detailed descriptions will be given later. These drawings and textual descriptions are not intended to limit the scope of the present invention in any way, but to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0032] Here, exemplary embodiments will be described in detail. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are only examples consistent with some aspects of the present invention as detailed in the appended claims.

[0033] The present invention provides a method for preparing a paper-plastic product, comprising the following steps:

[0034] S1) obtaining wet embryos of paper-plastic products through pulping and embryo copying processes;

[0035] S2) spraying a water-based waterproof coating on the surface of the wet embryo to form a water-based waterproof coating;

[0036] S3) hot pressing and shaping the wet embryo with the water-based waterproof coating obtained in S2) to obtain a product to be processed;

[0037] S4) contacting the surface of the product to be processed with a wax material to form a wax layer on the surface of the product to be processed, so as to prepare the paper-plastic product.

[0038] The present invention performs the pulping process and the embryo making process based on non-wood fiber materials to obtain the wet embryo of the paper-plastic product, wherein the non-wood fiber material includes one or more of bamboo and sedge.

[0039] The present invention selects non-wood pulp fibers with more abundant resources as raw materials, which not only protects forest resources but also makes full use of agricultural wastes.

[0040] The non-wood fiber may include long fiber pulp, or include long fibers and short fibers, wherein the mass content of the long fibers is preferably 60% to 100%, and the mass content of the short fibers is preferably 0 to 40%.

[0041] The long fibers may be non-wood pulp long fibers well known to those skilled in the art, including but not limited to bamboo pulp, asparagus pulp, and the like.

[0042] The long fibers of the present invention refer to fibers having a length of 2-3.5 mm.

[0043] The short fibers may be non-wood pulp short fibers well known to those skilled in the art, including but not limited to bagasse pulp, corn stalk pulp, and the like.

[0044] The short fibers of the present invention refer to fibers with a length of 0.8-1.1 mm.

[0045] The present invention firstly soaks the pulp board into water to make it fully absorb water and soften, and then puts it into a pulping machine for pulping.

[0046] The soaking time is preferably 20-30 minutes.

[0047] The beating time is preferably 10 to 15 minutes, and the speed of the beater is preferably 300-500 r / min.

[0048] The beating degree is preferably 20-24 SR°.

[0049] Then the crushed pulp sheet obtained by the above pulping process is moved to the pulp preparation tank, and a proper amount of clean water is added to adjust the pulp concentration to 0.3wt%-0.7wt%, and the pulp is fully stirred and pumped into the pulp suction tank for continuous circulation of the pulp.

[0050] Then, the weight parameters of the product are confirmed by adjusting the slurry absorption time. The slurry absorption mold is immersed in the slurry absorption pool to copy the embryo to obtain the wet embryo of the paper plastic product.

[0051] The vacuum degree of the embryo copying is preferably 0.06-0.08 MPa, and the slurry suction time is preferably 40-70 s.

[0052] The moisture content of the wet embryo of the paper plastic product is preferably 68%-73%.

[0053] Then spray water-based waterproof coating on the wet embryo surface of the paper plastic product to form a water-based waterproof coating.

[0054] Optionally, the water-based waterproof coating is a food-grade environmentally friendly water-based waterproof coating, and the food-grade environmentally friendly water-based waterproof coating is an oil-in-water emulsion formed by an aqueous phase material and an oil phase material.

[0055] In some specific embodiments of the present invention, the waterproof coating is mainly made of biomass materials, and the water-phase material and the oil-phase material are mixed by homogenization to form an oil-in-water emulsion, which has the characteristics of being fluorine-free, chlorine-free, renewable and biodegradable.

[0056] The aqueous phase material is preferably a natural polysaccharide substance, including but not limited to one or more of starch, chitosan, trehalose, cellulose and its derivatives.

[0057] The oil phase material is preferably one or more of rosin, wax, shellac, AKD (alkyl ketene dimer) and the like.

[0058] The volume content of the aqueous phase material is preferably 20%-30%.

[0059] The volume content of the oil phase material is preferably 20%-70%.

[0060] Preferably, the waterproof coating also contains an additive.

[0061] The auxiliary agent is preferably one or more of nano calcium carbonate, talc, clay, nano cellulose, lignin nano particles, and nano silicon dioxide.

[0062] The volume content of the auxiliary agent is preferably 2%-10%.

[0063] In some specific embodiments of the present invention, the waterproof coating component is:

[0064]

[0065] In some specific embodiments of the present invention, the waterproof coating component is:

[0066]

[0067] The spraying amount of the food-grade environmentally friendly water-based waterproof coating is preferably 3-5 g / m 2 .

[0068] Then, the wet embryo with the water-based waterproof coating is subjected to hot pressing and shaping to obtain the product to be processed.

[0069] The present invention uses the above-mentioned specific water-based waterproof coating, and the coating layer formed by the coating can be directly hot-pressed without the stickiness phenomenon that occurs in the hot-pressing process of conventional water-based waterproof coatings.

[0070] Optionally, the hot pressing and shaping is performed using a hot pressing and shaping machine.

[0071] The upper mold temperature of the thermoforming machine is preferably 140-160°C, and the lower mold temperature is preferably 120-140°C.

[0072] During the hot pressing process, the cylinder pressure is preferably 50-100 tons.

[0073] During the hot pressing process, the setting time is preferably 60-90s.

[0074] By limiting the parameters of the above-mentioned hot pressing molding, the water-based waterproof coating after hot pressing has an optimal flatness.

[0075] Then, the surface of the product to be processed is brought into contact with a food-grade wax material to form a wax layer on the surface of the product to be processed.

[0076] The present invention has no particular limitation on the contact method, including but not limited to conventional methods in the art such as dipping, smearing, and painting.

[0077] Optionally, the waxy material is a food grade waxy material, which can be a biomass wax well known to those skilled in the art, including but not limited to animal wax, plant wax, etc.

[0078] Preferably, the food-grade waxy material is in a molten state.

[0079] Preferably, the product to be processed after the hot pressing is placed in 100° C. molten food wax for dipping.

[0080] The food wax is preferably beeswax.

[0081] The dipping time is preferably 3-6 s, and the dipping amount is preferably 0.1-0.14 g.

[0082] The thickness of the formed wax layer is preferably 2 to 10 μm.

[0083] The above-mentioned paper-plastic product can be obtained after the wax layer is solidified.

[0084] The curing can be completed at room temperature.

[0085] Optionally, after hot pressing, the material is punched out to obtain a desired product shape, and then the wax layer is prepared.

[0086] The trimmings after punching can be re-entered into the pulping system for reuse.

[0087] The step of spraying the waterproof coating in the present invention is set to be after deep dehydration, followed by spraying and hot pressing, which cleverly utilizes the hot pressing molding process of traditional pulp molding without additional drying. At the same time, it also avoids the water absorption and deformation of the pulp molding product caused by spraying water-based coating.

[0088] The combination of environmentally friendly water-based coating and bio-wax material ensures that the product can be refrigerated, has high stiffness, and has no paper hair on the surface. It also has environmentally friendly properties such as being fluorine-free, chlorine-free, and biodegradable.

[0089] In the prior art, the waterproof and oil-proofing agents added to the slurry are mostly fluorine-containing compounds. Long carbon chain fluorine-containing substances have been proven to induce cancer and endanger health and the environment. Europe and the United States have issued corresponding policies to strictly control and restrict fluorine-containing compounds, and they will be gradually eliminated in the market in the future. The general surface spray waterproof coatings such as traditional petroleum-based materials such as acrylic acid and polyurethane have poor environmental properties and are prone to stickiness during direct hot pressing and shaping. They need to be dried separately, but the problem of product deformation is prone to occur during the drying process. The present invention adjusts the components of the water-based waterproof coating, and the coating layer formed can be directly hot-pressed and shaped without the stickiness that occurs in the hot pressing and shaping process of conventional water-based waterproof coatings.

[0090] Furthermore, the current production process of pulp molding is as follows:

[0091] Pulping (fiber pulp) - adding waterproof and oil-proof agent - embryo copying and deep dehydration - hot pressing and shaping - spraying water-based waterproof coating - drying in oven - punching.

[0092] This method requires hot pressing and shaping after deep dehydration, and then spraying a water-based waterproof coating and drying. The operation is relatively cumbersome, and pulp molded products are very prone to deformation after spraying water-based coatings and then drying, which affects the product qualification rate.

[0093] The present invention can directly spray the water-based waterproof coating on the surface of the wet embryo by adjusting the composition of the waterproof coating, and hot press to shape it, thereby eliminating the need for a separate drying process and making the operation more concise.

[0094] The paper-plastic product prepared by the preparation method of the present invention can be applied to the field of pulp molded ice cream sticks.

[0095] Based on this, the present invention provides a pulp molded ice cream stick, including a paper-plastic product obtained based on the above-mentioned preparation method.

[0096] Optionally, the pulp molded ice cream stick includes a non-wood fiber layer, a water-based coating layer compounded on the surface of the non-wood fiber layer, and a wax layer compounded on the water-based coating layer.

[0097] Figure 1 A schematic structural diagram of a pulp molded ice cream stick provided by the present invention.

[0098] The thickness of the non-wood fiber layer is preferably 1.8-2 mm.

[0099] The surface of the non-wood fiber layer is compounded with a water-based paint layer.

[0100] The thickness of the aqueous coating layer is preferably 0.5-2 μm.

[0101] The surface of the water-based paint layer is compounded with a wax layer.

[0102] The thickness of the wax layer is preferably 2 to 10 μm.

[0103] Since the present invention adopts non-wood fiber as raw material, the prepared popsicle stick has more diversified shapes, and can be prepared into a flat shape or a curved shape.

[0104] Figure 2 This is a schematic diagram of the product appearance of the pulp molded ice cream stick provided by the present invention, which has a curved shape.

[0105] The provision of the water-based coating layer in the pulp molded popsicle stick prepared by the present invention enhances the waterproofness of the pulp molded product in a wet environment, and at the same time has a good compressive property on the fine fibers on the surface of the pulp mold. The provision of the wax layer discharges the moisture inside the pulp mold, increases the overall stiffness of the product, and has strong waterproofness, eliminating the step of adding a waterproof and oil-proof agent to the traditional pulp mold slurry. Moreover, the materials used in the present invention are all food-grade environmentally friendly materials, which meet the environmental protection requirements of recycling and degradation.

[0106] Through the arrangement of the above structure, the pulp molded ice cream stick prepared by the present invention is not easy to absorb water and deform, has a smooth surface and has a high stiffness, and is more suitable for market application.

[0107] It should be noted that, in this article, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, or article including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, or article. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, method, or article including the element. In addition, features and elements with the same name in different embodiments of the present invention may have the same meaning or different meanings, and their specific meanings need to be determined by their explanation in the specific embodiment or further combined with the context of the specific embodiment.

[0108] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0109] Example 1

[0110] 1. Pulping: Soak sugarcane pulp and bamboo pulp in clean water at a mass ratio of 8:2 for 20 minutes to allow them to fully absorb water and soften. Put them into a pulping machine at 500r / min and beat for 15 minutes. The beating degree is 20-24SR° to obtain a crushed pulp board.

[0111] 2. Move the crushed pulp sheet to the slurry mixing tank, add appropriate amount of clean water, adjust the slurry concentration to 0.3%, stir it evenly, pump it into the slurry suction tank, and circulate the slurry continuously.

[0112] 3. Confirm the weight parameters of the product by adjusting the slurry absorption time. Immerse the slurry absorption mold in the slurry absorption pool, set the vacuum degree to 0.08MPa, and the slurry absorption time to 40s. After deep dehydration, a wet embryo with a moisture content of 68% to 73% is obtained and taken out for use.

[0113] 4. Spray the surface of the wet embryo obtained in the previous step with food-grade environmentally friendly water-based waterproof coating, with a spraying amount of 4g / m 2 , and obtain a sprayed wet blank.

[0114] The components of water-based waterproof coating are:

[0115]

[0116] 5. Put the sprayed wet blank obtained in the previous step into the hot pressing molding machine, set the upper mold temperature to 160℃, the lower mold temperature to 120℃, the cylinder pressure to 50 tons, and the shaping time to 60s. After shaping, punching is performed to obtain pulp molding products and trimming materials.

[0117] 6. The pulp molded product obtained in the previous step is dipped into 100° C. molten food wax (the wax used is beeswax) for 2 minutes and a dipping amount of 0.8 g.

[0118] 7. Place the products from the previous step onto the disinfection conveyor belt, turn on the ultraviolet light and the blowing function, and check whether the product appearance is qualified; then pack the disinfected and inspected samples.

[0119] 8. The trimmings obtained in step 5 are returned to the pulping system for reuse.

[0120] Example 2

[0121] 1. Pulping: Soak sugarcane pulp and sedge pulp in a mass ratio of 8:2 for 20 minutes to allow them to fully absorb water and soften. Put them into a pulping machine at 500r / min and beat for 15 minutes. The beating degree is 20-24SR° to obtain a crushed pulp board.

[0122] 2. Move the crushed pulp sheet to the slurry mixing tank, add appropriate amount of clean water, adjust the slurry concentration to 0.3%, stir it evenly, pump it into the slurry suction tank, and circulate the slurry continuously.

[0123] 3. Confirm the weight parameters of the product by adjusting the slurry absorption time. Immerse the slurry absorption mold in the slurry absorption pool, set the vacuum degree to 0.08MPa, and the slurry absorption time to 40s. After deep dehydration, a wet embryo with a moisture content of 68% to 73% is obtained and taken out for use.

[0124] 4. Spray the surface of the wet embryo obtained in the previous step with food-grade environmentally friendly water-based waterproof coating (with the same ingredients as in Example 1), with a spraying amount of 4g / m 2 , and obtain a sprayed wet blank.

[0125] 5. Put the sprayed wet blank obtained in the previous step into the hot pressing molding machine, set the upper mold temperature to 160℃, the lower mold temperature to 120℃, the cylinder pressure to 50 tons, and the shaping time to 60s. After shaping, punching is performed to obtain pulp molding products and trimming materials.

[0126] 6. The pulp molded product obtained in the previous step is dipped into 100° C. molten food wax (the wax used is beeswax) for 2 min and 0.8 g of dipping amount.

[0127] 7. Place the products from the previous step onto the disinfection conveyor belt, turn on the ultraviolet light and the blowing function, and check whether the product appearance is qualified; then pack the disinfected and inspected samples.

[0128] 8. The trimmings obtained in step 5 are returned to the pulping system for reuse.

[0129] Comparative Example 1 (only dipped in food wax)

[0130] 1. Pulping: Soak the sugarcane pulp board and bamboo pulp board in clean water at a mass ratio of 8:2 for 20 minutes to allow them to fully absorb water and soften. Put them into a pulping machine at 500r / min and beat for 15 minutes. The beating degree is 20-24SR° to obtain a crushed pulp board.

[0131] 2. Move the crushed pulp sheet to the slurry mixing tank, add appropriate amount of clean water, adjust the slurry concentration to 0.3%, stir it evenly, pump it into the slurry suction tank, and circulate the slurry continuously.

[0132] 3. Confirm the weight parameters of the product by adjusting the slurry absorption time. Immerse the slurry absorption mold in the slurry absorption pool, set the vacuum degree to 0.08MPa, and the slurry absorption time to 40s. After deep dehydration, a wet embryo with a moisture content of 68% to 73% is obtained and taken out for use.

[0133] 4. Put the wet blank obtained in the previous step into the hot pressing machine, set the upper mold temperature to 160℃, the lower mold temperature to 120℃, the cylinder pressure to 50 tons, and the shaping time to 60s. After shaping, punching is performed to obtain pulp molding products and trimming materials.

[0134] 5. The pulp molded product obtained in the previous step is dipped into 100° C. molten food wax (the wax used is beeswax) for 2 min and 0.8 g of dipping amount.

[0135] 6. Place the products from the previous step onto the disinfection conveyor belt, turn on the ultraviolet light and the blowing function, and check whether the product appearance is qualified; then pack the disinfected and inspected samples.

[0136] 7. The trimmings obtained in step 4 are returned to the pulping system for reuse.

[0137] Comparative Example 2 (Spraying water-based paint only)

[0138] 1. Pulping: Soak the sugarcane pulp board and bamboo pulp board in clean water at a mass ratio of 8:2 for 20 minutes to allow them to fully absorb water and soften. Put them into a pulping machine at 500r / min and beat for 15 minutes. The beating degree is 20-24SR° to obtain a crushed pulp board.

[0139] 2. Move the crushed pulp sheet to the slurry mixing tank, add appropriate amount of clean water, adjust the slurry concentration to 0.3%, stir it evenly, pump it into the slurry suction tank, and circulate the slurry continuously.

[0140] 3. Confirm the weight parameters of the product by adjusting the slurry absorption time. Immerse the slurry absorption mold in the slurry absorption pool, set the vacuum degree to 0.08MPa, the slurry absorption time to 40s, and after deep dehydration, a wet embryo with a moisture content of 68% to 73% is obtained, which is taken out for use.

[0141] 4. Spray the surface of the wet embryo obtained in the previous step with food-grade environmentally friendly water-based waterproof coating (with the same ingredients as in Example 1), with a spraying amount of 4g / m 2 , and obtain a sprayed wet blank.

[0142] 5. Put the sprayed wet blank obtained in the previous step into the hot pressing molding machine, set the upper mold temperature to 160℃, the lower mold temperature to 120℃, the cylinder pressure to 50 tons, and the shaping time to 60s. After shaping, punching is performed to obtain pulp molding products and trimming materials.

[0143] 6. Place the products from the previous step onto the disinfection conveyor belt, turn on the ultraviolet light and the blowing function, and check whether the product appearance is qualified; then pack the disinfected and inspected samples.

[0144] 7. The trimmings obtained in step 5 are returned to the pulping system for reuse.

[0145] Comparative Example 3 (no material was applied)

[0146] 1. Pulping: Mix sugarcane pulp and bamboo pulp in a ratio of 8:2 and soak them in clean water for 20 minutes to allow them to fully absorb water and soften. Put them into a pulping machine at 500r / min and beat them for 15 minutes. The beating degree is 20-24SR° to obtain a crushed pulp.

[0147] 2. Move the crushed pulp sheet to the slurry mixing tank, add appropriate amount of clean water, adjust the slurry concentration to 0.3%, stir it evenly, pump it into the slurry suction tank, and circulate the slurry continuously.

[0148] 3. Confirm the weight parameters of the product by adjusting the slurry absorption time. Immerse the slurry absorption mold in the slurry absorption pool, set the vacuum degree to 0.08MPa, and the slurry absorption time to 40s. After deep dehydration, a wet embryo with a moisture content of 68% to 73% is obtained and taken out for use.

[0149] 4. Put the sprayed wet blank obtained in the previous step into the hot pressing molding machine, set the upper mold temperature to 160℃, the lower mold temperature to 120℃, the cylinder pressure to 50 tons, and the shaping time to 60s. After shaping, punching is performed to obtain pulp molding products and trimming materials.

[0150] 5. Place the products from the previous step onto the disinfection conveyor belt, turn on the ultraviolet light and the blowing function, and check whether the product appearance is qualified; then pack the disinfected and inspected samples.

[0151] 6. The trimmings obtained in step 4 are returned to the pulping system for reuse.

[0152] Comparative Example 4 (adding waterproof and oil-proof agents to the slurry)

[0153] 1. Pulping: Mix sugarcane pulp and bamboo pulp in a ratio of 8:2 and soak them in clean water for 20 minutes to allow them to fully absorb water and soften. Put them into a pulping machine at 500r / min and beat them for 15 minutes. The beating degree is 20-24SR° to obtain a crushed pulp.

[0154] 2. Move the crushed pulp sheet to the slurry mixing tank, add appropriate amount of clean water, adjust the slurry concentration to 0.3%, stir it evenly, pump it into the slurry suction tank, and circulate the slurry continuously.

[0155] 3. Add food-grade environmentally friendly water-based waterproof coating and 100°C molten food wax (the wax used is beeswax) into the slurry. The waterproofing agent component is the same as in Example 1, and the addition amount is 4g / m 2 , the amount of beeswax added is 0.8g.

[0156] 4. Confirm the weight parameters of the product by adjusting the slurry absorption time. Immerse the slurry absorption mold in the slurry absorption pool, set the vacuum degree to 0.08MPa, and the slurry absorption time to 40s. After deep dehydration, a wet embryo with a moisture content of 68% to 73% is obtained, which is taken out for use.

[0157] 5. Put the sprayed wet blank obtained in the previous step into the hot pressing molding machine, set the upper mold temperature to 160℃, the lower mold temperature to 120℃, the cylinder pressure to 50 tons, and the shaping time to 60s. After shaping, punching is performed to obtain pulp molding products and trimming materials.

[0158] 6. Place the products from the previous step onto the disinfection conveyor belt, turn on the ultraviolet light and the blowing function, and check whether the product appearance is qualified; then pack the disinfected and inspected samples.

[0159] 7. The trimmings obtained in step 5 are returned to the pulping system for reuse.

[0160] Comparative Example 5 (using conventional waterproofing agent)

[0161] 1. Pulping: Soak the sugarcane pulp and bamboo pulp in clean water at a mass ratio of 8:2 for 20 minutes to allow them to fully absorb water and soften. Put them into a pulping machine at 500r / min and beat for 15 minutes. The beating degree is 20-24SR° to obtain a crushed pulp.

[0162] 2. Move the crushed pulp sheet to the slurry mixing tank, add appropriate amount of clean water, adjust the slurry concentration to 0.3%, stir it evenly, pump it into the slurry suction tank, and circulate the slurry continuously.

[0163] 3. Confirm the weight parameters of the product by adjusting the slurry absorption time. Immerse the slurry absorption mold in the slurry absorption pool, set the vacuum degree to 0.08MPa, and the slurry absorption time to 40s. After deep dehydration, a wet embryo with a moisture content of 68% to 73% is obtained and taken out for use.

[0164] 4. Spray the surface of the wet embryo obtained in the previous step with food-grade environmentally friendly water-based waterproof coating, with a spraying amount of 4g / m 2 , and obtain a sprayed wet blank.

[0165] The components of water-based waterproof coating are:

[0166] 10.0wt% ammonium persulfate aqueous solution containing 3.5wt% sodium bicarbonate 11.65wt%

[0167] 10.0wt% sodium dodecyl sulfate aqueous solution 27.72wt%

[0168] 90:10 vinyl acetate / acrylic acid mixture 60.63wt%

[0169] 5. Put the sprayed wet blank obtained in the previous step into the hot pressing molding machine, set the upper mold temperature to 140-160℃, the lower mold temperature to 120℃, the oil cylinder pressure to 50 tons, and the shaping time to 60s. After shaping, punching is performed to obtain pulp molding products and trimming materials. The product sticks to the mold during the hot pressing process.

[0170] 6. The pulp molded product obtained in the previous step is dipped into 100° C. molten food wax (the wax used is beeswax) for 3 minutes and a dipping amount of 0.8 g.

[0171] 7. Place the products from the previous step onto the disinfection conveyor belt, turn on the ultraviolet light and the blowing function, and check whether the product appearance is qualified; then pack the disinfected and inspected samples.

[0172] 8. The trimmings obtained in step 5 are returned to the pulping system for reuse.

[0173] Performance Testing

[0174] The appearance of the prepared pulp molded ice cream stick was tested, and the results are shown in Table 1:

[0175] Table 1

[0176]

[0177] It can be seen from the above results that the pulp molded popsicle sticks prepared by the present invention have excellent stiffness after being soaked in water for 10 minutes, are not easy to deform due to water absorption, and have a smooth surface without burrs. In contrast, in Comparative Example 1, the popsicle stick prepared by dipping in food wax easily absorbs water and has fine paper hairs on the surface, and has poor smoothness; in Comparative Example 2, the popsicle stick prepared by spraying water-based coating easily absorbs water and deforms easily; in Comparative Example 3, the popsicle stick prepared without dipping in any material is severely deformed after being soaked in water and cannot be tested; in Comparative Example 4, the popsicle stick prepared by adding waterproofing agent and oil-proofing agent to the slurry has poor stiffness after being soaked in water, deforms due to water absorption, and has many fine paper hairs on the surface; in Comparative Example 5, the popsicle stick prepared by using conventional waterproofing agent sticks to the mold during the hot pressing process, has poor stiffness after being soaked in water, becomes soft due to water absorption, and has many fine paper hairs on the surface. Obviously, the popsicle sticks prepared in Comparative Examples 1-5 are not suitable for market applications.

[0178] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a paper-plastic product, characterized in that: The following steps are involved: S1) obtaining wet embryos of paper-plastic products through pulping and embryo copying processes; S2) spraying a water-based waterproof coating on the surface of the wet embryo to form a water-based waterproof coating; S3) hot pressing and shaping the wet embryo with the water-based waterproof coating obtained in S2) to obtain a product to be processed; S4) contacting the surface of the product to be processed with a wax material to form a wax layer on the surface of the product to be processed, so as to prepare the paper-plastic product.

2. The method for preparing a paper-plastic product according to claim 1, characterized in that: The water-based waterproof coating is a food-grade environmentally friendly water-based waterproof coating, and the food-grade environmentally friendly water-based waterproof coating is an oil-in-water emulsion formed by an aqueous phase material and an oil phase material; The wax material is a food grade wax material; And / or, the S1) includes: performing the pulping process and the embryo copying process based on non-wood fiber materials to obtain the wet embryo of the paper-plastic product, wherein the non-wood fiber material includes one or more of bamboo and sedge.

3. The method for preparing a paper-plastic product according to claim 2, characterized in that: The aqueous phase material is selected from natural polysaccharides; The oil phase material is selected from one or more of rosin, wax, shellac and AKD.

4. The method for preparing a paper-plastic product according to claim 2, characterized in that: The spraying amount of the food-grade environmentally friendly water-based waterproof coating is 3-5g / m 2 .

5. The method for preparing a paper-plastic product according to claim 1, characterized in that: The moisture content of the wet embryo is 68%-73%.

6. The method for preparing a paper-plastic product according to claim 1, characterized in that: The hot pressing and shaping is completed by using a hot pressing and shaping machine; The upper mold temperature of the thermoforming machine is 140-160°C, and the lower mold temperature is 120-140°C; The oil cylinder pressure is 50-100 tons; The setting time is 60-90s.

7. A pulp molded popsicle stick, characterized in that: It includes a paper-plastic product obtained based on the preparation method according to any one of claims 1 to 6.

8. The pulp molded popsicle stick according to claim 7, characterized in that: The invention comprises a non-wood fiber layer, a water-based paint layer compounded on the surface of the non-wood fiber layer, and a wax layer compounded on the water-based paint layer.

9. The pulp molded popsicle stick according to claim 8, characterized in that: The thickness of the water-based coating layer is 0.5-2 μm; and / or, The thickness of the non-wood fiber layer is 1.8-2 mm.

10. The pulp molded popsicle stick according to claim 8, characterized in that: The thickness of the wax layer is 2-10 μm.

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