High-temperature-resistant paper straw water-based adhesive and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant paper straw water-based adhesive and a preparation method thereof, belongs to the technical field of adhesives, and is used for solving the problem that in the prior art, the wet viscosity and the high-temperature-resistant performance of a paper straw adhesive need to be improved. Adding lauryl sodium sulfate, iso-tridecanol polyoxyethylene ether, food-grade modified silicon dioxide and a food-grade defoaming agent, continuously stirring, adding butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, diacetone acrylamide and a vinyl acetate-ethylene copolymer emulsion, adding ammonium persulfate, heating, carrying out a heat preservation reaction, and cooling to room temperature; after the reaction is finished, cooling, adding hydrogen peroxide and ascorbic acid, continuously cooling, adjusting the pH value by using a sodium bicarbonate aqueous solution, adding adipic dihydrazide, adding a food-grade defoaming agent and potassium sorbate, and adjusting the material viscosity to obtain the high-temperature-resistant paper straw water-based adhesive. The adhesive has a good bonding effect and is more water-resistant and high-temperature-resistant.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and in particular to a high-temperature resistant water-based adhesive for paper straws and a preparation method thereof. Background Art

[0002] With the increasing variety of food, various types of food contact materials are constantly emerging and becoming more diverse. As a result, food safety issues have received widespread attention from all sectors of society. When food contact materials and products come into contact with food, toxic and harmful substances contained in them may migrate into the food or react chemically with food ingredients. This not only easily causes food contamination, but also poses a threat to human health. Straws are a common tool for drinking beverages, with a large usage volume and a wide range of applications. Because plastic straws pose serious harm to the environment and organisms, paper straws are gradually becoming an alternative. The production of paper straws requires adhesives, whose main function is to bond the paper material of paper straws together. However, existing paper straws have obvious technical shortcomings: they easily become damp and soften when exposed to water, and cannot be immersed in water for long periods of time. At the same time, paper straws inevitably pass through the human mouth during use and come into direct contact with food, which places extremely high demands on the safety of adhesives. In addition, when people use them to drink hot drinks such as milk tea and coffee, due to the influence of temperature, the adhesive film of the paper straws will be stratified after being soaked for a long time, which greatly reduces their bonding effect.

[0003] In view of the technical defects in this aspect, a solution is now proposed. Summary of the Invention

[0004] The purpose of the present invention is to provide a high-temperature resistant water-based adhesive for paper straws and a preparation method thereof, which is used to solve the problem in the prior art that the wet adhesion and high-temperature resistance of paper straw adhesives need to be improved, while meeting food requirements and not endangering human health.

[0005] In order to achieve the above objectives, the present invention provides a method for preparing a high-temperature resistant water-based adhesive for paper straws, comprising the following steps:

[0006] Add polyvinyl alcohol to water, heat and stir to dissolve, add sodium lauryl sulfate, isomeric tridecyl alcohol polyoxyethylene ether, food-grade modified silica and food-grade defoamer, continue stirring, gradually and slowly add butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, diacetone acrylamide and vinyl acetate-ethylene copolymer emulsion in sequence, stir, add ammonium persulfate, heat, keep warm to react, after the reaction is completed, cool, and simultaneously add hydrogen peroxide and ascorbic acid aqueous solution, continue cooling, adjust the pH to 6.5-7.0 with sodium bicarbonate aqueous solution, add adipic acid dihydrazide, add food-grade defoamer and potassium sorbate, adjust the viscosity of the material, filter, and discharge to obtain a high-temperature resistant water-based adhesive for paper straws;

[0007] Among them, the preparation method of food-grade modified silicon dioxide includes:

[0008] The food-grade amorphous silica is added into water, ultrasonically dispersed, a PVA solution is added, the temperature is increased, the mixture is stirred, centrifuged, washed, and vacuum dried to obtain the food-grade modified silica.

[0009] Preferably, the preparation of the vinyl acetate-ethylene copolymer emulsion comprises the following steps:

[0010] Adding vinyl acetate-ethylene copolymer and water into a dispersing kettle, stirring, slowly increasing the temperature, and continuing stirring to allow the vinyl acetate-ethylene copolymer to initially swell; then adding sodium lauryl sulfate, increasing the stirring speed, and shearing and dispersing to disperse the vinyl acetate-ethylene copolymer into latex particles; cooling, adding potassium sorbate and a food-grade defoamer, and adjusting the pH to 5.5-6.5 with citric acid, continuing stirring, and filtering to obtain a vinyl acetate-ethylene copolymer emulsion;

[0011] Among them, the heating temperature is 60-70℃;

[0012] Among them, the cooling temperature is 40-50℃;

[0013] Among them, the food-grade defoamer is polysorbate;

[0014] Among them, the mass ratio of vinyl acetate-ethylene copolymer, water, sodium lauryl sulfate, potassium sorbate and food-grade defoaming agent is 100:(120-150):(2-4):(0.1-0.3):(0.05-0.2).

[0015] Preferably, the mass ratio of polyvinyl alcohol, water, sodium lauryl sulfate, isomeric tridecanol polyoxyethylene ether, food-grade modified silica, food-grade defoamer, butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, diacetone acrylamide, vinyl acetate-ethylene copolymer emulsion, ammonium persulfate, hydrogen peroxide, ascorbic acid, sodium bicarbonate aqueous solution, adipic acid dihydrazide, and potassium sorbate is (2-5):(55-65):(0. 1-0.4):(0.1-0.4):(0.8-1.2):(0.1-0.3):(4-10):(4-10):(2-5):(0.2-0.6):(0.2-0.6):(10-30):(0.05-0.2):(0.01-0.05):(0.01-0.05):(0.1-0.2):(0.1-0.3):(0.1-0.3).

[0016] Preferably, the mass concentration of the sodium bicarbonate aqueous solution is 20-30%.

[0017] Preferably, the heat preservation reaction conditions are as follows: heat preservation at 86-90° C. for 0.8-1.2 h.

[0018] Preferably, the first heating temperature is 80-85° C.; and the stirring and dissolving time is 0.8-1 h.

[0019] Preferably, the first cooling temperature is 60-65°C.

[0020] Preferably, the second cooling temperature is 45-50°C.

[0021] Preferably, the addition time is 50-60 min.

[0022] Preferably, the material viscosity is 3000-9000 cps.

[0023] Preferably, the food grade defoamer is food grade white oil.

[0024] Preferably, the mass concentration of the ascorbic acid aqueous solution is 20-30%.

[0025] Preferably, the mass ratio of food-grade amorphous silica, water and PVA solution is (60-80):(200-400):(300-500).

[0026] Preferably, the PVA solution is prepared as follows: PVA and water are mixed in a mass ratio of (5-10): (40-50), heated to 80-90° C., stirred until completely dissolved, and cooled to room temperature to obtain a PVA solution.

[0027] Preferably, the vacuum drying conditions are: 0.08 MPa, 50-55° C., and vacuum drying for 8-10 h.

[0028] Preferably, a high-temperature resistant water-based adhesive for paper straws is prepared by the preparation method of the high-temperature resistant water-based adhesive for paper straws.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The present invention uses food-grade amorphous silica as one of the fillers. As an inorganic particle, it can improve the mechanical properties. At the same time, because it is resistant to high temperatures, its addition will increase the high-temperature resistance of the adhesive. The food-grade modified silica modified with PVA has good compatibility with vinyl acetate-ethylene copolymer emulsion, which is conducive to forming a stable mixed colloid and avoiding stratification during storage. The PVA therein acts as a film-forming agent. The hydroxyl groups in its molecular chain can form hydrogen bonds with the surface of paper fibers, providing initial bonding force and ensuring rapid bonding during paper straw molding. The polar ester groups in the vinyl acetate-ethylene copolymer emulsion, the hydroxyl groups of PVA, and the hydroxyl groups of the paper fibers form multiple hydrogen bonds, significantly improving the compatibility and adhesion of the system. The flexible ethylene segments in the vinyl acetate-ethylene copolymer are interspersed between the rigid segments of the matrix material, alleviating the brittleness caused by the hard monomer, so that the film still maintains bonding integrity when repeatedly bent; at the same time, the ethylene segments enhance the flexibility of the film, avoiding debonding due to paper deformation.

[0031] 2. The butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, and diacetone acrylamide in the present invention can react chemically under the action of ammonium persulfate to obtain a copolymer. At the same time, the addition of vinyl acetate-ethylene copolymer emulsion can further increase the toughness of the copolymer; diacetone acrylamide is embedded in the chain of the copolymer, and it forms a hydrazone bond with adipic acid dihydrazide under neutral conditions. The formed hydrazone bond can further form a cross-linked structure between the copolymer and the vinyl acetate-ethylene copolymer, further improving the cohesive strength and water resistance of the adhesive. This cross-linked structure can effectively resist the intrusion of moisture, prevent the adhesive from swelling or losing viscosity when in contact with water, and ensure that the paper straw can still maintain good bonding properties when holding liquids. The presence of hydrazone bonds also enhances the thermal stability of the adhesive, allowing the adhesive to maintain good performance even in high temperature environments. At the same time, food-grade modified silica is evenly dispersed in the film, filling the gaps between the molecular chains, obstructing the penetration path of the liquid, improving the heat resistance of the film, and further enhancing the synergistic stability of the system, ensuring storage without stratification or flocculation.

[0032] 3. The emulsifier of sodium lauryl sulfate and isomeric tridecanol polyoxyethylene ether in the present invention reduces the surface tension of the system, makes the adhesive spread evenly when applied, and slows down the water evaporation rate at the same time, prolongs the open time. At the same time, in the present invention, ammonium persulfate initiates copolymerization, controls the polymerization rate, and then adopts hydrogen peroxide and ascorbic acid to carry out gentle reaction, both eliminates residual monomers and does not accelerate surface crusting, ensuring that the open time is stable. The addition of food-grade defoamer not only meets the requirements of food contact, but also suppresses the generation of bubbles during the coating process, while reducing the local drying caused by uneven surface tension too fast, and maintaining the open time.

[0033] 4. The raw materials used in the present invention are all food-grade or food-contact-compliant, and no toxic or harmful additives are introduced. There are no harmful residues during the preparation process, and the final product meets the safety standards for food contact materials, ensuring that paper straws do not endanger human health when in contact with food and beverages. The preparation method of the high-temperature-resistant water-based adhesive for paper straws provided by the present invention is stable and the product has strong applicability. The product viscosity can be adjusted to 3000-9000cps, which is suitable for the coating process in paper straw production. The addition of potassium sorbate can effectively extend the shelf life, improve the product's practicality, and facilitate industrial production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a product diagram of the high-temperature resistant paper straw water-based adhesive prepared by the present invention used for paper straws. DETAILED DESCRIPTION

[0035] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] Example 1

[0037] This embodiment provides a method for preparing a high-temperature resistant water-based adhesive for paper straws, comprising the following steps:

[0038] Add polyvinyl alcohol to water, heat to 80°C, stir and dissolve for 1 hour, add sodium lauryl sulfate, isomeric tridecyl alcohol polyoxyethylene ether, food-grade modified silica and food-grade white oil, continue stirring for 10 minutes, gradually and slowly add butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, diacetone acrylamide and vinyl acetate-ethylene copolymer emulsion in sequence, stir, add ammonium persulfate, heat to 86°C and keep warm for 1.2 hours, the reaction is completed, cool to 60°C, and simultaneously add hydrogen peroxide and 20wt% ascorbic acid aqueous solution, and the addition is completed within 60 minutes, continue to cool to 45°C, adjust the pH to 7.0 with 20wt% sodium bicarbonate aqueous solution, add adipic acid dihydrazide, add food-grade white oil and potassium sorbate, adjust to a viscosity of 3000cps, filter, and discharge to obtain a high-temperature resistant paper straw water-based adhesive;

[0039] Among them, the mass ratio of polyvinyl alcohol, water, sodium lauryl sulfate, isomeric tridecyl alcohol polyoxyethylene ether, food-grade modified silica, food-grade white oil, butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, diacetone acrylamide, vinyl acetate-ethylene copolymer emulsion, ammonium persulfate, hydrogen peroxide, ascorbic acid, sodium bicarbonate aqueous solution, adipic acid dihydrazide, and potassium sorbate is 2:55:0.1:0.1:0.8:0.1:4:4:2:0.2:0.2:10:0.05:0.01:0.01:0.1:0.1:0.1;

[0040] Among them, the preparation method of food-grade modified silicon dioxide includes:

[0041] Food-grade amorphous silica was added to water, ultrasonically dispersed at a frequency of 30 kHz for 15 minutes, and a PVA solution was added. The mixture was heated to 50°C, stirred at a speed of 200 r / min for 2 hours, centrifuged at a speed of 8000 r / min for 10 minutes, washed with deionized water, and vacuum dried at 0.08 MPa and 50°C for 10 hours to obtain food-grade modified silica.

[0042] Among them, the mass ratio of food-grade amorphous silica, water and PVA solution is 60:200:300.

[0043] Example 2

[0044] This embodiment provides a method for preparing a high-temperature resistant water-based adhesive for paper straws, comprising the following steps:

[0045] Add polyvinyl alcohol to water, heat to 81°C, stir and dissolve for 1 hour, add sodium lauryl sulfate, isomeric tridecyl alcohol polyoxyethylene ether, food-grade modified silica and food-grade white oil, continue stirring for 12 minutes, gradually and slowly add butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, diacetone acrylamide and vinyl acetate-ethylene copolymer emulsion in sequence, stir, add ammonium persulfate, heat to 87°C and keep warm for 1.1 hours, the reaction is completed, cool to 61°C, and hydrogen peroxide and 20wt% ascorbic acid aqueous solution are added simultaneously, and the addition is completed within 58 minutes, continue to cool to 46°C, adjust the pH to 7.0 with 20wt% sodium bicarbonate aqueous solution, add adipic acid dihydrazide, add food-grade white oil and potassium sorbate, adjust to a viscosity of 4500cps, filter, and discharge to obtain a high-temperature resistant paper straw water-based adhesive;

[0046] Among them, the mass ratio of polyvinyl alcohol, water, sodium lauryl sulfate, isomeric tridecyl alcohol polyoxyethylene ether, food-grade modified silica, food-grade white oil, butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, diacetone acrylamide, vinyl acetate-ethylene copolymer emulsion, ammonium persulfate, hydrogen peroxide, ascorbic acid, sodium bicarbonate aqueous solution, adipic acid dihydrazide, and potassium sorbate is 2.75:57:0.18:0.18:0.9:0.15:5.5:5.5:2.7:0.3:0.3:15:0.08:0.02:0.02:0.12:0.15:0.15;

[0047] Among them, the preparation method of food-grade modified silicon dioxide includes:

[0048] Food-grade amorphous silica was added to water, ultrasonically dispersed at a frequency of 32 kHz for 14 minutes, and a PVA solution was added. The mixture was heated to 51°C, stirred at a speed of 220 r / min for 2 hours, centrifuged at a speed of 8250 r / min for 9 minutes, washed with deionized water, and vacuum dried at 0.08 MPa and 51°C for 9.5 hours to obtain food-grade modified silica.

[0049] Among them, the mass ratio of food-grade amorphous silica, water and PVA solution is 65:250:350.

[0050] Example 3

[0051] This embodiment provides a method for preparing a high-temperature resistant water-based adhesive for paper straws, comprising the following steps:

[0052] Add polyvinyl alcohol to water, heat to 82°C, stir and dissolve for 0.9h, add sodium lauryl sulfate, isomeric tridecyl alcohol polyoxyethylene ether, food-grade modified silica and food-grade white oil, continue stirring for 14min, gradually and slowly add butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, diacetone acrylamide and vinyl acetate-ethylene copolymer emulsion in sequence, stir, add ammonium persulfate, heat to 88°C and keep warm for 1h, the reaction is completed, cool to 62°C, and simultaneously add hydrogen peroxide and 20wt% ascorbic acid aqueous solution, and the addition is completed within 55min, continue to cool to 48°C, adjust the pH to 6.7 with 25wt% sodium bicarbonate aqueous solution, add adipic acid dihydrazide, add food-grade white oil and potassium sorbate, adjust to a viscosity of 6000cps, filter, and discharge to obtain a high-temperature resistant paper straw water-based adhesive;

[0053] Among them, the mass ratio of polyvinyl alcohol, water, sodium lauryl sulfate, isomeric tridecyl alcohol polyoxyethylene ether, food-grade modified silica, food-grade white oil, butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, diacetone acrylamide, vinyl acetate-ethylene copolymer emulsion, ammonium persulfate, hydrogen peroxide, ascorbic acid, sodium bicarbonate aqueous solution, adipic acid dihydrazide, and potassium sorbate is 3.5:60:0.25:0.25:1:0.2:7:7:3.5:0.4:0.4:20:0.12:0.03:0.03:0.15:0.2:0.2;

[0054] Among them, the preparation method of food-grade modified silicon dioxide includes:

[0055] Food-grade amorphous silica was added to water, ultrasonically dispersed at a frequency of 35 kHz for 12 minutes, and PVA solution was added. The temperature was raised to 53°C, stirred at a speed of 250 r / min for 1.9 hours, centrifuged at a speed of 8500 r / min for 9 minutes, washed with deionized water, and vacuum dried at 0.08 MPa and 53°C for 9 hours to obtain food-grade modified silica.

[0056] Among them, the mass ratio of food-grade amorphous silica, water and PVA solution is 70:300:400.

[0057] Example 4

[0058] This embodiment provides a method for preparing a high-temperature resistant water-based adhesive for paper straws, comprising the following steps:

[0059] Add polyvinyl alcohol to water, heat to 84°C, stir and dissolve for 0.8h, add sodium lauryl sulfate, isomeric tridecyl alcohol polyoxyethylene ether, food-grade modified silica and food-grade white oil, continue stirring for 16min, gradually and slowly add butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, diacetone acrylamide and vinyl acetate-ethylene copolymer emulsion in sequence, stir, add ammonium persulfate, heat to 89°C and keep warm for 0.9h, the reaction is completed, cool to 63°C, and hydrogen peroxide and 20wt% ascorbic acid aqueous solution are added at the same time, and the addition is completed within 57min, continue to cool to 49°C, adjust the pH to 6.5 with 30wt% sodium bicarbonate aqueous solution, add adipic acid dihydrazide, add food-grade white oil and potassium sorbate, adjust to a viscosity of 7500cps, filter, and discharge to obtain a high-temperature resistant paper straw water-based adhesive;

[0060] Among them, the mass ratio of polyvinyl alcohol, water, sodium lauryl sulfate, isomeric tridecyl alcohol polyoxyethylene ether, food-grade modified silica, food-grade white oil, butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, diacetone acrylamide, vinyl acetate-ethylene copolymer emulsion, ammonium persulfate, hydrogen peroxide, ascorbic acid, sodium bicarbonate aqueous solution, adipic acid dihydrazide, and potassium sorbate is 4.2:62:0.32:0.32:1.1:0.25:8.5:8.5:4.2:0.5:0.5:25:0.18:0.04:0.04:0.18:0.25:0.25;

[0061] Among them, the preparation method of food-grade modified silicon dioxide includes:

[0062] Food-grade amorphous silica was added to water, ultrasonically dispersed at a frequency of 37 kHz for 11 minutes, and PVA solution was added. The temperature was raised to 54°C, stirred at a speed of 275 r / min for 1.8 hours, centrifuged at a speed of 8750 r / min for 8 minutes, washed with deionized water, and vacuum dried at 0.08 MPa and 54°C for 8 hours to obtain food-grade modified silica.

[0063] Among them, the mass ratio of food-grade amorphous silica, water and PVA solution is 75:350:450.

[0064] Example 5

[0065] This embodiment provides a method for preparing a high-temperature resistant water-based adhesive for paper straws, comprising the following steps:

[0066] Add polyvinyl alcohol to water, heat to 85°C, stir and dissolve for 0.8h, add sodium lauryl sulfate, isomeric tridecyl alcohol polyoxyethylene ether, food-grade modified silica and food-grade white oil, continue stirring for 18min, gradually and slowly add butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, diacetone acrylamide and vinyl acetate-ethylene copolymer emulsion in sequence, stir, add ammonium persulfate, heat to 90°C and keep warm for 0.8h, the reaction is completed, cool to 65°C, and hydrogen peroxide and 20wt% ascorbic acid aqueous solution are added at the same time, and the addition is completed within 60min, continue to cool to 50°C, adjust the pH to 6.5 with 30wt% sodium bicarbonate aqueous solution, add adipic acid dihydrazide, add food-grade white oil and potassium sorbate, adjust to a viscosity of 9000cps, filter, and discharge to obtain a high-temperature resistant paper straw water-based adhesive;

[0067] Among them, the mass ratio of polyvinyl alcohol, water, sodium lauryl sulfate, isomeric tridecyl alcohol polyoxyethylene ether, food-grade modified silica, food-grade white oil, butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, diacetone acrylamide, vinyl acetate-ethylene copolymer emulsion, ammonium persulfate, hydrogen peroxide, ascorbic acid, sodium bicarbonate aqueous solution, adipic acid dihydrazide, and potassium sorbate is 5:65:0.4:0.4:1.2:0.3:10:10:5:0.6:0.6:30:0.2:0.05:0.05:0.2:0.3:0.3;

[0068] Among them, the preparation method of food-grade modified silicon dioxide includes:

[0069] Food-grade amorphous silica was added to water, ultrasonically dispersed at a frequency of 40 kHz for 10 minutes, and PVA solution was added. The mixture was heated to 55°C, stirred at a speed of 300 r / min for 1.8 hours, centrifuged at a speed of 9000 r / min for 8 minutes, washed with deionized water, and vacuum dried at 0.08 MPa and 55°C for 8 hours to obtain food-grade modified silica.

[0070] Among them, the mass ratio of food-grade amorphous silica, water and PVA solution is 80:400:500.

[0071] Example 6

[0072] This embodiment provides a method for preparing a vinyl acetate-ethylene copolymer emulsion, comprising the following steps:

[0073] Vinyl acetate-ethylene copolymer and water were added to a dispersion kettle, stirred at 300 r / min for 15 minutes, and the temperature was slowly increased to 60°C. The mixture was kept stirred for 45 minutes to allow the vinyl acetate-ethylene copolymer particles to initially swell. Subsequently, sodium lauryl sulfate was added, the stirring speed was increased to 800 r / min, and shear dispersion was performed for 1.2 hours to disperse the vinyl acetate-ethylene copolymer particles into latex particles. The temperature was lowered to 45°C, potassium sorbate and polysorbate were added, and the pH of the system was adjusted to 6 with 10% citric acid water. The mixture was stirred for 30 minutes and filtered through a 200-mesh filter to obtain a vinyl acetate-ethylene copolymer emulsion.

[0074] Among them, the mass ratio of vinyl acetate-ethylene copolymer, water, sodium lauryl sulfate, potassium sorbate and polysorbate is 100:120:2:0.1:0.05.

[0075] Example 7

[0076] This embodiment provides a method for preparing a PVA solution, comprising the following steps:

[0077] PVA and water were mixed in a mass ratio of 5:40, heated to 90° C., stirred until completely dissolved, and cooled to room temperature to obtain a PVA solution.

[0078] Comparative Example 1

[0079] This comparative example provides a method for preparing a water-based adhesive for paper straws, comprising the following steps:

[0080] Add polyvinyl alcohol to water, heat to 80°C, stir and dissolve for 1 hour, add sodium lauryl sulfate, isomeric tridecyl alcohol polyoxyethylene ether and food-grade white oil, continue stirring for 10 minutes, gradually and slowly add butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, diacetone acrylamide and vinyl acetate-ethylene copolymer emulsion in sequence, stir, add ammonium persulfate, heat to 86°C and keep warm for 1.2 hours, the reaction is completed, cool to 60°C, and hydrogen peroxide and 20wt% ascorbic acid aqueous solution are added simultaneously, and the addition is completed within 60 minutes, continue to cool to 45°C, adjust the pH to 7.0 with 20wt% sodium bicarbonate aqueous solution, add adipic acid dihydrazide, add food-grade white oil and potassium sorbate, adjust to a viscosity of 3000cps, filter, and discharge to obtain a high-temperature resistant paper straw water-based adhesive;

[0081] Among them, the mass ratio of polyvinyl alcohol, water, sodium lauryl sulfate, isomeric tridecyl alcohol polyoxyethylene ether, food-grade white oil, butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, diacetone acrylamide, vinyl acetate-ethylene copolymer emulsion, ammonium persulfate, hydrogen peroxide, ascorbic acid, sodium bicarbonate aqueous solution, adipic acid dihydrazide, and potassium sorbate is 2:55.8:0.1:0.1:0.1:4:4:2:0.2:0.2:10:0.05:0.01:0.01:0.1:0.1:0.1:0.1.

[0082] Comparative Example 2

[0083] This comparative example provides a method for preparing a water-based adhesive for paper straws, comprising the following steps:

[0084] Add polyvinyl alcohol to water, heat to 80°C, stir and dissolve for 1 hour, add sodium lauryl sulfate, isomeric tridecyl alcohol polyoxyethylene ether and food-grade white oil, continue stirring for 10 minutes, gradually and slowly add butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, diacetone acrylamide in sequence, stir, add ammonium persulfate, heat to 86°C and keep warm for 1.2 hours, the reaction is completed, cool to 60°C, and simultaneously add hydrogen peroxide and 20wt% ascorbic acid aqueous solution, and the addition is completed within 60 minutes, continue to cool to 45°C, adjust the pH to 7.0 with 20wt% sodium bicarbonate aqueous solution, add adipic acid dihydrazide, add food-grade white oil and potassium sorbate, adjust to a viscosity of 3000cps, filter, and discharge to obtain a high-temperature resistant paper straw water-based adhesive;

[0085] Among them, the mass ratio of polyvinyl alcohol, water, sodium lauryl sulfate, isomeric tridecyl alcohol polyoxyethylene ether, food-grade white oil, butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, diacetone acrylamide, ammonium persulfate, hydrogen peroxide, ascorbic acid, sodium bicarbonate aqueous solution, adipic acid dihydrazide, and potassium sorbate is 2:65.8:0.1:0.1:0.1:4:4:2:0.2:0.2:0.05:0.01:0.01:0.1:0.1:0.1.

[0086] Comparative Example 3

[0087] This comparative example provides a method for preparing a conventional water-based adhesive for paper straws, comprising the following steps:

[0088] Pour pure water into a stirring kettle, start stirring, slowly add polyvinyl alcohol, disperse for 10 minutes, then open the condenser of the stirring kettle, close the stirring kettle, open the jacket and heat to 85°C, keep warm for 1 hour until the polyvinyl alcohol is completely dissolved, open the jacket after dissolution and cool to the internal material temperature of 45°C, then add vinyl acetate-ethylene copolymer emulsion, vinyl acetate homopolymer emulsion, and kaolin in sequence, stir for 30 minutes until uniform, add defoamer, stir for 15 minutes, then add boric acid aqueous solution, stir for 20 minutes, then add preservative, stir for 10 minutes, test the viscosity after stirring, adjust the viscosity to 3000cps, filter the material through 150 mesh after passing the test, and obtain a conventional paper straw water-based adhesive;

[0089] The raw material composition of ordinary paper straw water-based adhesive is shown in Table 1 below:

[0090] Table 1

[0091]

[0092] The vinyl acetate-ethylene copolymer emulsions in Examples 1-5 of the present invention and Comparative Examples 1 and 3 all adopt the vinyl acetate-ethylene copolymer emulsion prepared in Example 6.

[0093] The PVA solutions in Examples 1-5 of the present invention all adopt the PVA solution prepared in Example 7.

[0094] Performance testing:

[0095] The water-based adhesives prepared in Examples 1-5 and Comparative Examples 1-3 were tested accordingly. The test results are shown in Table 2 below:

[0096] Table 2

[0097]

[0098] A comparative analysis of the data in Table 2 shows that the high-temperature resistant water-based adhesive for paper straws prepared by the present invention meets the requirements and is better than the comparative example. It has obvious advantages in resistance to hot water and various beverages, and has good bonding effect.

[0099] The above content is merely an example and explanation of the structure of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

[0100] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0101] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a high-temperature resistant water-based adhesive for paper straws, characterized in that: The following steps are involved: Add polyvinyl alcohol to water, heat and stir to dissolve, add sodium lauryl sulfate, isomeric tridecyl alcohol polyoxyethylene ether, food-grade modified silica and food-grade defoamer, continue stirring, gradually and slowly add butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, diacetone acrylamide and vinyl acetate-ethylene copolymer emulsion in sequence, stir, add ammonium persulfate, heat, keep warm to react, after the reaction is completed, cool, add hydrogen peroxide and ascorbic acid aqueous solution, continue cooling, adjust the pH to 6.5-7.0 with sodium bicarbonate aqueous solution, add adipic acid dihydrazide, add food-grade defoamer and potassium sorbate, adjust the viscosity of the material to obtain a high-temperature resistant paper straw water-based adhesive; Among them, the preparation method of food-grade modified silicon dioxide includes: The food-grade amorphous silica is added into water, ultrasonically dispersed, a PVA solution is added, the temperature is increased, the mixture is stirred, centrifuged, washed, and vacuum dried to obtain the food-grade modified silica.

2. The method for preparing a high-temperature resistant water-based adhesive for paper straws according to claim 1, characterized in that: The mass ratio of polyvinyl alcohol, water, sodium lauryl sulfate, isomeric tridecyl alcohol polyoxyethylene ether, food grade modified silica, food grade defoamer, butyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid, diacetone acrylamide, vinyl acetate-ethylene copolymer emulsion, ammonium persulfate, hydrogen peroxide, ascorbic acid, sodium bicarbonate aqueous solution, adipic acid dihydrazide, and potassium sorbate is (2-5):(55-65):(0.1- 0.4):(0.1-0.4):(0.8-1.2):(0.1-0.3):(4-10):(4-10):(2-5):(0.2-0.6):(0.2-0.6):(10-30):(0.05-0.2):(0.01-0.05):(0.01-0.05):(0.1-0.2):(0.1-0.3):(0.1-0.3).

3. The method for preparing a high-temperature resistant water-based adhesive for paper straws according to claim 1, characterized in that: The preparation of vinyl acetate-ethylene copolymer emulsion comprises the following steps: Add vinyl acetate-ethylene copolymer and water into a dispersion kettle, stir, slowly increase the temperature, and continue stirring to allow the vinyl acetate-ethylene copolymer to initially swell; then add sodium lauryl sulfate, increase the stirring speed, and shear and disperse to disperse the vinyl acetate-ethylene copolymer into latex particles; cool, add potassium sorbate and a food-grade defoamer, adjust the pH to 5.5-6.5 with citric acid, continue stirring, and filter to obtain a vinyl acetate-ethylene copolymer emulsion.

4. The method for preparing a high-temperature resistant water-based adhesive for paper straws according to claim 1, characterized in that: The specific conditions for the heat preservation reaction are: heat preservation at 86-90°C for 0.8-1.2h.

5. The method for preparing a high-temperature resistant water-based adhesive for paper straws according to claim 1, characterized in that: The material viscosity is 3000-9000cps.

6. The method for preparing a high-temperature resistant water-based adhesive for paper straws according to claim 1, characterized in that: Food grade defoamer is food grade white oil.

7. The method for preparing a high-temperature resistant water-based adhesive for paper straws according to claim 1, characterized in that: The mass ratio of food-grade amorphous silica, water and PVA solution is (60-80):(200-400):(300-500).

8. The method for preparing a high-temperature resistant water-based adhesive for paper straws according to claim 1, characterized in that: The PVA solution was prepared as follows: PVA and water were mixed in a mass ratio of (5-10): (40-50), heated to 80-90° C., stirred until completely dissolved, and cooled to room temperature to obtain a PVA solution.

9. The method for preparing a high-temperature resistant water-based adhesive for paper straws according to claim 1, characterized in that: The vacuum drying conditions are: 0.08 MPa, 50-55°C, vacuum drying for 8-10 hours.

10. A high temperature resistant water-based adhesive for paper straws, characterized in that: The invention is prepared by the preparation method of the high-temperature resistant water-based adhesive for paper straws described in any one of claims 1 to 9.

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