A high-strength lightweight packaging carton and a method for manufacturing the same

Abstract

The application relates to the technical field of packaging cartons, and discloses a high-strength lightweight packaging carton and a preparation method thereof. The preparation steps are as follows: S1: uniformly mixing trihydroxy heptaoctyl poss, 3-bromopropylene, sodium carbonate and tetrahydrofuran, reacting at 50-60 DEG C for 3-5 h to obtain modified poss; S2: taking hexamethoxymethyl melamine, ethanol and the modified poss to prepare a modified etherified amino resin; S3: uniformly mixing the modified etherified amino resin, mercapto-modified silicon dioxide and a photoinitiator to obtain an additive; uniformly stirring acrylic emulsion, epoxy / acrylic core-shell emulsion, hyperbranched polyurethane acrylate and the additive to obtain reinforcing coating; and coating the reinforcing coating on the surface of the lightweight packaging carton, drying and curing to obtain the high-strength lightweight packaging carton.

Description

Technical Field

[0001] This invention relates to the field of packaging carton technology, and discloses a high-strength lightweight packaging carton and its preparation method. Background Technology

[0002] With the rapid development of the logistics and packaging industries, the demand for packaging cartons is constantly increasing, and the trend towards "low weight, high strength, and lightweight" has become a major focus. Currently, the strength and water resistance of lightweight packaging cartons still need improvement. When facing humid environments or needing to withstand significant pressure, these cartons are prone to deformation and damage. To improve carton performance, surface coating technology has received widespread attention. By spraying specific coatings onto the surface of cartons, not only can waterproofing be effectively achieved, but the strength of the cartons can also be significantly increased. However, existing coating technologies still have some shortcomings in practical applications. For example, the adhesion of the coating is relatively weak, and it is prone to peeling or detachment during transportation, folding, or long-term storage, affecting the overall strength and performance of the cartons. Therefore, researching a high-strength, lightweight packaging carton with good surface waterproofing and strong adhesion, and its preparation method, is of great significance. Summary of the Invention

[0003] The purpose of this invention is to provide a high-strength, lightweight packaging carton and its preparation method, so as to solve the problems mentioned in the background art.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing a high-strength lightweight packaging carton, comprising the following steps:

[0005] S1: Mix trihydroxyheptaoctylposs, 3-bromopropene, sodium carbonate, and tetrahydrofuran evenly, and react at 50-60℃ for 3-5 hours to obtain modified poss;

[0006] S2: Take the silica composition, add it to a mixed solution of water and ethanol, heat it to 50-60℃, stir it evenly, add 3-mercaptopropyltriethoxysilane, keep it warm and stir for 4-6 hours, remove the solvent, and obtain mercapto-modified silica.

[0007] S3: Take hexamethylol melamine, ethanol, and modified poss, stir evenly, adjust the pH value to 3-4, heat to 40-55℃ and stir evenly, keep warm for 1-2 hours, adjust the pH to 8-10, control the vacuum degree to 0.06-0.09MPa, and react under vacuum conditions of 90-105℃ for 2-4 hours to obtain modified etherified amino resin;

[0008] S4: Take modified etherified amino resin, mercapto-modified silica, and photoinitiator, mix them evenly to obtain additives; take acrylic emulsion, epoxy / acrylic core-shell emulsion, hyperbranched polyurethane acrylate, and additives, stir them evenly to obtain reinforcing coating; apply the reinforcing coating to the surface of lightweight packaging cartons, dry and cure to obtain high-strength lightweight packaging cartons.

[0009] In a more optimized manner, the molar ratio of trihydroxyheptaoctylposs, 3-bromopropene, and sodium carbonate is 1:(1-1.2):(1-1.2); the amount of tetrahydrofuran added is 4-10 times the total mass of trihydroxyheptaoctylposs, 3-bromopropene, and sodium carbonate; the mercapto-modified silica comprises the following raw materials, by mass parts: 10-15 parts silica composition, 1-1.5 parts 3-mercaptopropyltriethoxysilane, and 50-80 parts a mixed solution of water and ethanol (the volume ratio of water to ethanol is 1:1). :1); The molar ratio of hexamethylol melamine, ethanol, and modified POSS is 1:(3~5):(2~4); The additives include the following raw materials, by mass parts: 3~4 parts modified etherified amino resin, 2~4 parts mercapto-modified silica, 0.1~0.2 parts photoinitiator; The reinforced coatings include the following raw materials, by mass parts: 15~25 parts acrylic emulsion, 6~10 parts epoxy / acrylic core-shell emulsion, 10~15 parts hyperbranched polyurethane acrylate, 5~9 parts additives.

[0010] Ideally, the basis weight of the paper used to prepare the lightweight cardboard box is less than 100 g / m².

[0011] More preferably, the silica composition comprises 1-3 μm silica and 10-20 nm silica in a mass ratio of (1-2):1.

[0012] More preferably, the silica composition comprises 1μm silica and 20nm silica in a mass ratio of 2:1.

[0013] In a more optimized manner, the preparation of the epoxy / acrylic core-shell emulsion includes the following steps: Step 1: Mix epoxy resin, phthalic anhydride, and dimethyl ethylenediamine, heat to 130°C for reaction, and when the acid value is <8mg KOH / g, add decanoic acid, cool to 115-120°C, and reflux for 2-4 hours to obtain modified epoxy resin;

[0014] Step 2: Mix propyl 2,2,3,3,3-pentafluoro-2-fluoroacrylate, acrylic acid, methacrylic acid, octadecyl acrylate, and hydroquinone evenly to obtain a monomer composition; dissolve α-methylstyrene and benzoyl peroxide in propylene glycol methyl ether, heat to 70-80°C, add the monomer composition dropwise, heat to 80-90°C and react for 3-4 hours, add modified epoxy resin, stir evenly, react at 110°C for 1-2 hours, cool to 50-55°C, add triethylamine and stir for 30-60 minutes, remove the solvent, add water, and stir at high speed to obtain an epoxy / acrylic core-shell emulsion.

[0015] In a more optimized manner, the epoxy / acrylic core-shell emulsion comprises the following raw materials, by mass parts: 12-15 parts epoxy resin, 2-3 parts phthalic anhydride, 0.04-0.06 parts dimethyl ethylenediamine, 3-4 parts decanoic acid, 0.8-1.5 parts propyl 2,2,3,3,3-pentafluoro-2-fluoroacrylate, 3-4 parts acrylic acid, 2-3 parts methacrylic acid, 0.4-0.6 parts octadecyl acrylate, 0.01-0.02 parts hydroquinone, 1-2 parts α-methylstyrene, 0.3-0.5 parts benzoyl peroxide, 4-5 parts propylene glycol methyl ether, and 4-5 parts triethylamine; the amount of water added is 1.5-2 times the mass of the monomer composition.

[0016] In a more optimized manner, the preparation of the hyperbranched polyurethane acrylate includes the following steps: adding polytetrahydrofuran diol-1000 to acetone and stirring until homogeneous, heating to 70-80°C, adding isophorone diisocyanate and dibutyltin dilaurate, stirring and reacting for 2-3 hours to obtain an isocyanate-terminated prepolymer; adding a chain extender, reacting at 60-70°C for 2-3 hours, adding hydroxyethyl methacrylate dropwise and stirring until the content of isocyanate groups in the system reaches the theoretical endpoint, removing acetone by rotary evaporation to obtain the hyperbranched polyurethane acrylate.

[0017] In a more optimized manner, the hyperbranched polyurethane acrylate comprises the following raw materials, by mass parts: 20-30 parts polytetrahydrofuran diol, 20-30 parts acetone, 15-20 parts isophorone diisocyanate, 0.5-1 part dibutyltin dilaurate, and 3-5 parts chain extender.

[0018] More preferably, the chain extender comprises octahydroxybutylposs and 1,3-propanediol in a mass ratio of (2-3):(1-2).

[0019] Ideally, when the reinforcing coating is applied to the surface of lightweight packaging cartons, the coating amount on one side is 15–25 g / m². 2 The curing process is as follows: UV irradiation for 20-30 minutes, followed by drying at 100-120℃ for 1-2 hours.

[0020] Compared with the prior art, the beneficial effects achieved by the present invention are: coating the surface of a lightweight packaging carton with a reinforcing coating, the reinforcing coating comprising acrylic emulsion, epoxy / acrylic core-shell emulsion, hyperbranched polyurethane acrylate, and additives;

[0021] The acrylic emulsion uses ROSF-5588, a special acrylic emulsion for organic-inorganic composites, which has strong adhesion. The epoxy / acrylic core-shell emulsion combines the advantages of strong adhesion and good water resistance of epoxy resin with the good film-forming properties of acrylic resin. Furthermore, the addition of fluorinated propyl acrylate and long-chain acrylate further enhances the coating's waterproof performance. Hyperbranched polyurethane acrylate introduces a polyurethane structure, improving abrasion resistance. The degree of branching is controlled by the addition ratio of octahydroxybutylposs and 1,3-propanediol. The addition of octahydroxybutylposs increases the degree of branching, optimizes film-forming properties, and has a similar structure to the additives, improving their affinity. However, the addition ratio should not be too high, as excessive addition leads to over-branching, reducing the compatibility of the hyperbranched polyurethane acrylate with the acrylic emulsion and epoxy / acrylic core-shell emulsion, thus affecting performance. In summary, this solution obtains a coating matrix by blending acrylic emulsion, epoxy / acrylic core-shell emulsion, and hyperbranched polyurethane acrylate and controlling the addition ratio, resulting in a coating with good compatibility, strong adhesion, and high strength.

[0022] The additives include modified etherified amino resin, mercapto-modified silica, and a photoinitiator. The modified etherified amino resin is obtained by reacting hydroxyl-containing modified POSS, ethanol, and hexamethylol melamine, and plays an auxiliary curing role in the coating. The modified POSS contains heptaoctyl, which further improves the waterproofness of the coating, and contains double bonds, which can participate in the crosslinking reaction in subsequent steps, improving the compatibility of the additives with the coating matrix. The mercapto-modified silica is a silica composition modified by mercaptosilane coupling agent, including 1μm silica and 20nm silica, forming a particle size gradient, which improves dispersibility and strength. The amount of mercapto-modified silica added also needs to be controlled. On the one hand, in order to reduce weight, the amount of inorganic filler added should not be too much. On the other hand, the mercapto groups can crosslink with the double bonds in the modified etherified amino resin and hyperbranched polyurethane acrylate in the subsequent ultraviolet irradiation, acting as a crosslinking agent, which can improve the compatibility of the two and increase the degree of crosslinking to improve strength. However, excessive addition will lead to over-crosslinking and thus a decrease in performance. In summary, the additives prepared in this scheme can further improve the waterproofness, strength, and adhesion of the coating, and have good dispersibility. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that there are no special restrictions on the manufacturers of the raw materials involved in this invention. Exemplary examples include: ethanol (CAS: 64-17-5); acrylic emulsion (ROSF-5588, Rosef); epoxy resin (E-20, Nanjing Bermuda Biotechnology); dimethyl ethylenediamine (CAS: 110-70-3); polytetrahydrofuran glycol-1000 (Shandong Suihua Biotechnology); octahydroxybutyl POSS (3131, Xi'an Qiyue Biotechnology); 1,3-propanediol (CAS: 504-63-2); trihydroxyheptaoctyl POSS (JH-P302, Shanghai Jiehua New Materials); sodium carbonate (anhydrous sodium carbonate); 1μm silica, 20nm silica (Zhejiang Manli Nanotechnology); hexahydroxymethyl melamine (CAS: 3089-11-0); photoinitiator (photoinitiator TPO, CAS: 75980-60-8).

[0025] Unless otherwise specified, all figures below are parts by weight or mass ratios.

[0026] Preparation of epoxy / acrylic core-shell emulsion: 14 parts of E-20 epoxy resin, 2.5 parts of phthalic anhydride, and 0.05 parts of dimethylethylenediamine were mixed, stirred, and slowly heated to 130℃ for reaction. The acid value was monitored during the reaction. When the acid value was <8 mg KOH / g, 4 parts of decanoic acid were added, the temperature was lowered to 120℃, and refluxed for 4 hours to obtain modified epoxy resin. 1 part of 2,2,3,3,3-pentafluoro-2-fluoroacrylate, 3 parts of acrylic acid, 3 parts of methacrylic acid, and 0.5 parts of propylene were mixed. Octadecyl ester and 0.01 parts hydroquinone were mixed evenly to obtain a monomer composition; 1 part α-methylstyrene and 0.4 parts benzoyl peroxide were dissolved in 5 parts propylene glycol methyl ether, heated to 70°C, and the monomer composition was added dropwise. The mixture was heated to 90°C and reacted for 4 hours. Modified epoxy resin was added, stirred evenly, and reacted at 110°C for 2 hours. The mixture was cooled to 55°C, and 5 parts triethylamine were added and stirred for 30 minutes. The solvent was removed, and water with a mass of 1.5 times that of the monomer composition was added. The mixture was stirred at high speed to obtain an epoxy / acrylic core-shell emulsion.

[0027] The silica composition is 1μm silica and 20nm silica in a mass ratio of 2:1;

[0028] In a mixed solution of water and ethanol, the volume ratio of water to ethanol is 1:1.

[0029] Example 1: S1: 25 parts of polytetrahydrofuran diol-1000 were added to 30 parts of acetone, stirred evenly, heated to 70°C, 20 parts of isophorone diisocyanate and 0.5 parts of dibutyltin dilaurate were added, and the mixture was stirred and reacted for 3 hours to obtain an isocyanate-terminated prepolymer; 2 parts of octahydroxybutylposs and 2 parts of 1,3-propanediol were added, and the mixture was reacted at 70°C for 3 hours. Hydroxyethyl methacrylate was added dropwise and stirred until the content of isocyanate groups in the system reached the theoretical endpoint by toluene-di-n-butylamine titration. Acetone was removed by rotary evaporation to obtain hyperbranched polyurethane acrylate.

[0030] S2: Mix trihydroxyheptaoctylposs, 3-bromopropene, sodium carbonate, and tetrahydrofuran evenly, and react at 60°C for 4 hours to obtain modified poss; the molar ratio of trihydroxyheptaoctylposs, 3-bromopropene, and sodium carbonate is 1:1:1; the amount of tetrahydrofuran added is 6 times the total mass of trihydroxyheptaoctylposs, 3-bromopropene, and sodium carbonate.

[0031] S3: Take 15 parts of the silica composition, add it to a mixed solution of 80 parts of water and ethanol, heat it to 60°C, stir it evenly, add 1.5 parts of 3-mercaptopropyltriethoxysilane, keep it warm and stir for 6 hours, remove the solvent, and obtain mercapto-modified silica.

[0032] S4: Take hexamethylol melamine, ethanol and modified poss in a molar ratio of 1:3:3, stir evenly, adjust the pH value to 3, heat to 50℃ and stir evenly, keep the reaction at this temperature for 2 hours, adjust the pH to 9, start the vacuum pump, control the vacuum degree to 0.06MPa, and dehydrate under vacuum conditions at 100℃ for 4 hours to obtain modified etherified amino resin.

[0033] S5: Take 3 parts of modified etherified amino resin, 4 parts of mercapto-modified silica, and 0.1 parts of photoinitiator, mix them evenly to obtain the additive; mix 20 parts of acrylic emulsion, 8 parts of epoxy / acrylic core-shell emulsion, 14 parts of hyperbranched polyurethane acrylate, and 7.1 parts of additive evenly to obtain the reinforcing coating; apply the reinforcing coating to the surface of lightweight packaging cartons, with a single-sided coating amount of 18 g / m². 2 After irradiating with ultraviolet light for 30 minutes and drying at 120℃ for 1 hour, a high-strength, lightweight packaging carton is obtained.

[0034] Example 2: S1: 20 parts of polytetrahydrofuran diol-1000 were added to 30 parts of acetone, stirred evenly, heated to 70°C, 15 parts of isophorone diisocyanate and 0.5 parts of dibutyltin dilaurate were added, and the mixture was stirred for 3 hours to obtain an isocyanate-terminated prepolymer; 2 parts of octahydroxybutylposs and 1 part of 1,3-propanediol were added, and the mixture was reacted at 70°C for 3 hours. Hydroxyethyl methacrylate was added dropwise and stirred until the content of isocyanate groups in the system reached the theoretical endpoint by toluene-di-n-butylamine titration. Acetone was removed by rotary evaporation to obtain hyperbranched polyurethane acrylate.

[0035] S2: Trihydroxyheptaoctylposs, 3-bromopropene, sodium carbonate, and tetrahydrofuran are mixed evenly and reacted at 60°C for 4 hours to obtain modified poss; the molar ratio of trihydroxyheptaoctylposs, 3-bromopropene, and sodium carbonate is 1:1.2:1.2; the amount of tetrahydrofuran added is 6 times the total mass of trihydroxyheptaoctylposs, 3-bromopropene, and sodium carbonate;

[0036] S3: Take 15 parts of the silica composition, add it to a mixed solution of 80 parts of water and ethanol, heat it to 60°C, stir it evenly, add 1.5 parts of 3-mercaptopropyltriethoxysilane, keep it warm and stir for 6 hours, remove the solvent, and obtain mercapto-modified silica.

[0037] S4: Take hexamethylol melamine, ethanol, and modified poss in a molar ratio of 1:3:4, stir evenly, adjust the pH value to 3, heat to 50℃ and stir evenly, keep the reaction at this temperature for 2 hours, adjust the pH to 9, start the vacuum pump, control the vacuum degree to 0.06MPa, and dehydrate under vacuum conditions at 100℃ for 4 hours to obtain modified etherified amino resin.

[0038] S5: Take 4 parts of modified etherified amino resin, 4 parts of mercapto-modified silica, and 0.1 parts of photoinitiator, mix them evenly to obtain the additive; mix 25 parts of acrylic emulsion, 10 parts of epoxy / acrylic core-shell emulsion, 15 parts of hyperbranched polyurethane acrylate, and 8.1 parts of additive evenly to obtain the reinforcing coating; apply the reinforcing coating to the surface of lightweight packaging cartons, with a single-sided coating amount of 18 g / m². 2 After irradiating with ultraviolet light for 30 minutes and drying at 120℃ for 1 hour, a high-strength, lightweight packaging carton is obtained.

[0039] Comparative Example 1 (the amount of raw materials added to the reinforcing coating was changed, and the rest of the methods and steps were the same as in Example 1): S1: 25 parts of polytetrahydrofuran diol-1000 were added to 30 parts of acetone, stirred evenly, heated to 70°C, 20 parts of isophorone diisocyanate and 0.5 parts of dibutyltin dilaurate were added, and the mixture was stirred and reacted for 3 hours to obtain an isocyanate-terminated prepolymer; 2 parts of octahydroxybutylposs and 2 parts of 1,3-propanediol were added, and the mixture was reacted at 70°C for 3 hours. Hydroxyethyl methacrylate was added dropwise and stirred until the content of isocyanate groups in the system reached the theoretical endpoint by toluene-di-n-butylamine titration. Acetone was removed by rotary evaporation to obtain hyperbranched polyurethane acrylate.

[0040] S2: Mix trihydroxyheptaoctylposs, 3-bromopropene, sodium carbonate, and tetrahydrofuran evenly, and react at 60°C for 4 hours to obtain modified poss; the molar ratio of trihydroxyheptaoctylposs, 3-bromopropene, and sodium carbonate is 1:1:1; the amount of tetrahydrofuran added is 6 times the total mass of trihydroxyheptaoctylposs, 3-bromopropene, and sodium carbonate.

[0041] S3: Take 15 parts of the silica composition, add it to a mixed solution of 80 parts of water and ethanol, heat it to 60°C, stir it evenly, add 1.5 parts of 3-mercaptopropyltriethoxysilane, keep it warm and stir for 6 hours, remove the solvent, and obtain mercapto-modified silica.

[0042] S4: Take hexamethylol melamine, ethanol and modified poss in a molar ratio of 1:3:3, stir evenly, adjust the pH value to 3, heat to 50℃ and stir evenly, keep the reaction at this temperature for 2 hours, adjust the pH to 9, start the vacuum pump, control the vacuum degree to 0.06MPa, and dehydrate under vacuum conditions at 100℃ for 4 hours to obtain modified etherified amino resin.

[0043] S5: Take 3 parts of modified etherified amino resin, 4 parts of mercapto-modified silica, and 0.1 parts of photoinitiator, mix them evenly to obtain the additive; mix 30 parts of acrylic emulsion, 3 parts of epoxy / acrylic core-shell emulsion, 9 parts of hyperbranched polyurethane acrylate, and 7.1 parts of additive evenly to obtain the reinforcing coating; apply the reinforcing coating to the surface of lightweight packaging cartons, with a single-sided coating amount of 18 g / m². 2 After irradiating with ultraviolet light for 30 minutes and drying at 120℃ for 1 hour, a high-strength, lightweight packaging carton is obtained.

[0044] Comparative Example 2 (octahydroxybutylposs replaces 1,3-propanediol, and the remaining steps are the same as in Example 1): S1: 25 parts of polytetrahydrofurandiol-1000 are added to 30 parts of acetone, stirred evenly, heated to 70°C, 20 parts of isophorone diisocyanate and 0.5 parts of dibutyltin dilaurate are added, and the mixture is stirred and reacted for 3 hours to obtain an isocyanate-terminated prepolymer; 4 parts of octahydroxybutylposs are added, and the mixture is reacted at 70°C for 3 hours; hydroxyethyl methacrylate is added dropwise and stirred until the content of isocyanate groups in the system reaches the theoretical endpoint as determined by toluene-di-n-butylamine titration; acetone is removed by rotary evaporation to obtain hyperbranched polyurethane acrylate;

[0045] S2: Mix trihydroxyheptaoctylposs, 3-bromopropene, sodium carbonate, and tetrahydrofuran evenly, and react at 60°C for 4 hours to obtain modified poss; the molar ratio of trihydroxyheptaoctylposs, 3-bromopropene, and sodium carbonate is 1:1:1; the amount of tetrahydrofuran added is 6 times the total mass of trihydroxyheptaoctylposs, 3-bromopropene, and sodium carbonate.

[0046] S3: Take 15 parts of the silica composition, add it to a mixed solution of 80 parts of water and ethanol, heat it to 60°C, stir it evenly, add 1.5 parts of 3-mercaptopropyltriethoxysilane, keep it warm and stir for 6 hours, remove the solvent, and obtain mercapto-modified silica.

[0047] S4: Take hexamethylol melamine, ethanol and modified poss in a molar ratio of 1:3:3, stir evenly, adjust the pH value to 3, heat to 50℃ and stir evenly, keep the reaction at this temperature for 2 hours, adjust the pH to 9, start the vacuum pump, control the vacuum degree to 0.06MPa, and dehydrate under vacuum conditions at 100℃ for 4 hours to obtain modified etherified amino resin.

[0048] S5: Take 3 parts of modified etherified amino resin, 4 parts of mercapto-modified silica, and 0.1 parts of photoinitiator, mix them evenly to obtain the additive; mix 20 parts of acrylic emulsion, 8 parts of epoxy / acrylic core-shell emulsion, 14 parts of hyperbranched polyurethane acrylate, and 7.1 parts of additive evenly to obtain the reinforcing coating; apply the reinforcing coating to the surface of lightweight packaging cartons, with a single-sided coating amount of 18 g / m². 2 After irradiating with ultraviolet light for 30 minutes and drying at 120℃ for 1 hour, a high-strength, lightweight packaging carton is obtained.

[0049] Comparative Example 3 (the preparation method of the additive was changed, and the rest of the steps were the same as in Example 1): S1: 25 parts of polytetrahydrofuran diol-1000 were added to 30 parts of acetone, stirred evenly, heated to 70°C, 20 parts of isophorone diisocyanate and 0.5 parts of dibutyltin dilaurate were added, and the mixture was stirred for 3 hours to obtain an isocyanate-terminated prepolymer; 2 parts of octahydroxybutylposs and 2 parts of 1,3-propanediol were added, and the mixture was reacted at 70°C for 3 hours. Hydroxyethyl methacrylate was added dropwise and stirred until the content of isocyanate groups in the system reached the theoretical endpoint by toluene-di-n-butylamine titration. Acetone was removed by rotary evaporation to obtain hyperbranched polyurethane acrylate.

[0050] S2: Take hexamethylol melamine, ethanol, and trihydroxyheptaoctyl poss in a molar ratio of 1:3:3, stir evenly, adjust the pH value to 3, heat to 50℃ and stir evenly, keep the temperature for 2 hours, adjust the pH to 9, start the vacuum pump, control the vacuum degree to 0.06MPa, and dehydrate under vacuum conditions at 100℃ for 4 hours to obtain modified etherified amino resin.

[0051] S3: Take 3 parts of modified etherified amino resin and 4 parts of silica composition, mix them evenly to obtain the additive; mix 20 parts of acrylic emulsion, 8 parts of epoxy / acrylic core-shell emulsion, 14 parts of hyperbranched polyurethane acrylate, and 7 parts of additive evenly to obtain the reinforcing coating; apply the reinforcing coating to the surface of lightweight packaging cartons, with a single-sided coating amount of 18 g / m². 2 After irradiating with ultraviolet light for 30 minutes and drying at 120℃ for 1 hour, a high-strength, lightweight packaging carton is obtained.

[0052] Comparative Example 4 (the amount of raw materials added to the reinforcing coating was changed, and the rest of the methods and steps were the same as in Example 1): S1: 25 parts of polytetrahydrofuran diol-1000 were added to 30 parts of acetone, stirred evenly, heated to 70°C, 20 parts of isophorone diisocyanate and 0.5 parts of dibutyltin dilaurate were added, and the mixture was stirred and reacted for 3 hours to obtain an isocyanate-terminated prepolymer; 2 parts of octahydroxybutylposs and 2 parts of 1,3-propanediol were added, and the mixture was reacted at 70°C for 3 hours. Hydroxyethyl methacrylate was added dropwise and stirred until the content of isocyanate groups in the system reached the theoretical endpoint by toluene-di-n-butylamine titration. Acetone was removed by rotary evaporation to obtain hyperbranched polyurethane acrylate.

[0053] S2: Mix trihydroxyheptaoctylposs, 3-bromopropene, sodium carbonate, and tetrahydrofuran evenly, and react at 60°C for 4 hours to obtain modified poss; the molar ratio of trihydroxyheptaoctylposs, 3-bromopropene, and sodium carbonate is 1:1:1; the amount of tetrahydrofuran added is 6 times the total mass of trihydroxyheptaoctylposs, 3-bromopropene, and sodium carbonate.

[0054] S3: Take 15 parts of the silica composition, add it to a mixed solution of 80 parts of water and ethanol, heat it to 60°C, stir it evenly, add 1.5 parts of 3-mercaptopropyltriethoxysilane, keep it warm and stir for 6 hours, remove the solvent, and obtain mercapto-modified silica.

[0055] S4: Take hexamethylol melamine, ethanol and modified poss in a molar ratio of 1:3:3, stir evenly, adjust the pH value to 3, heat to 50℃ and stir evenly, keep the reaction at this temperature for 2 hours, adjust the pH to 9, start the vacuum pump, control the vacuum degree to 0.06MPa, and dehydrate under vacuum conditions at 100℃ for 4 hours to obtain modified etherified amino resin.

[0056] S5: Take 3 parts of modified etherified amino resin, 4 parts of mercapto-modified silica, and 0.1 parts of photoinitiator, mix them evenly to obtain the additive; mix 10 parts of acrylic emulsion, 15 parts of epoxy / acrylic core-shell emulsion, 17 parts of hyperbranched polyurethane acrylate, and 7.1 parts of additive evenly to obtain the reinforcing coating; apply the reinforcing coating to the surface of lightweight packaging cartons, with a single-sided coating amount of 18 g / m². 2 After irradiating with ultraviolet light for 30 minutes and drying at 120℃ for 1 hour, a high-strength, lightweight packaging carton is obtained.

[0057] Performance testing: High-strength lightweight packaging cartons prepared in Examples 1-2 and Comparative Examples 1-4 were used; (1) the bursting strength was tested according to GB / T6545-1998; (2) the static contact angle was tested; (3) 600-mesh sandpaper was placed on the surface of the cartons and dragged 10 times under the pressure of a 400g weight, with each drag distance being 20cm, and the static contact angle after friction was tested again; see Table 1 for details;

[0058] Table 1:

[0059]

[0060] Conclusion: Comparative Example 1 showed that changing the amount of raw materials added to the reinforced coating resulted in an increase in the amount of acrylic emulsion added and an increase in the epoxy / acrylic ratio. Acid core The reduced addition of shell emulsion and hyperbranched polyurethane acrylate led to a decrease in performance, highlighting the importance of raw material ratio. Comparative Example 2, by replacing 1,3-propanediol with octahydroxybutylposs, resulted in excessively high branching of the hyperbranched polyurethane acrylate, leading to performance degradation. Comparative Example 3 altered the additive preparation method, directly preparing a modified etherified amino resin from hexamethylolmelamine, ethanol, and trihydroxyheptaoctylposs, and then mixing the modified etherified amino resin with a silica composition to obtain the additive. This reduced the compatibility of the additive with other components and decreased the overall crosslinking degree, resulting in performance degradation. Comparative Example 4 increased the addition of epoxy / acrylic core-shell emulsion, but its performance was inferior to the examples. In summary, the high-strength, lightweight packaging carton prepared by this invention exhibits good burst strength, strong water resistance, good adhesion between the coating and the carton body, and good abrasion resistance.

[0061] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of making a high-strength lightweight packaging carton, characterized by: Comprise the following steps: S1: the trihydroxy seven octyl poss, 3-bromo propylene, sodium carbonate, tetrahydrofuran is mixed uniformly, 50~60℃ reaction 3~5h, the modified poss is obtained;Wherein, the molar ratio of trihydroxy seven octyl poss, 3-bromo propylene, sodium carbonate is 1: (1~1.2) : (1~1.2); S2: take the silica composition, add the mixed solution of water and ethanol, warm to 50~60℃, stir uniformly, add 3-mercapto propyl triethoxysilane, keep warm and stir for 4~6h, remove the solvent, and obtain the mercapto modified silica; S3: take the hexamethylol melamine, ethanol, modified poss, stir uniformly, adjust the pH value to 3~4, warm to 40~55℃ and stir uniformly, keep warm and react for 1~2h, adjust the pH to 8~10, control the vacuum degree to 0.06~0.09MPa, react under the condition of 90~105℃ vacuum for 2~4h, and obtain the modified etherification amino resin; S4: take the modified etherification amino resin, mercapto modified silica and photoinitiator, mix uniformly, and obtain the additive;Take the acrylic emulsion, epoxy / acrylic core-shell emulsion, hyperbranched polyurethane acrylate and additive, stir uniformly, and obtain the reinforcing coating;Coat the reinforcing coating on the surface of the lightweight packaging carton, dry and solidify, and obtain the high-strength lightweight packaging carton; The reinforcing coating comprises the following raw materials in parts by mass: 15~25 parts of acrylic emulsion, 6~10 parts of epoxy / acrylic core-shell emulsion, 10~15 parts of hyperbranched polyurethane acrylate and 5~9 parts of additive; The silica composition comprises 1~3μm silica and 10~20nm silica in a mass ratio of (1~2) : 1; The hyperbranched polyurethane acrylate comprises the following raw materials in parts by mass: 20~30 parts of polytetrahydrofuran diol, 20~30 parts of acetone, 15~20 parts of isophorone diisocyanate, 0.5~1 part of dibutyltin dilaurate and 3~5 parts of chain extender; The chain extender comprises octyl poss and 1,3-propanediol in a mass ratio of (2~3) : (1~2); 2. A method of making a high-strength lightweight packaging carton according to claim 1, characterized in that: The mercapto modified silica comprises the following raw materials in parts by mass: 10~15 parts of silica composition and 1~1.5 parts of 3-mercapto propyl triethoxysilane;The molar ratio of hexamethylol melamine, ethanol and modified poss is 1: (3~5) : (2~4);The additive comprises the following raw materials in parts by mass: 3~4 parts of modified etherification amino resin, 2~4 parts of mercapto modified silica and 0.1~0.2 parts of photoinitiator.

3. The method of claim 1, wherein the method further comprises: The preparation of the epoxy / acrylic core-shell emulsion comprises the following steps: Step one: mix epoxy resin, phthalic anhydride and dimethyl ethylenediamine, warm to 130℃ and react, add capric acid when the acid value is less than 8mg KOH / g, cool to 115~120℃, and condense backflow for 2~4h to obtain modified epoxy resin; Step two: mix 2,2,3,3,3-pentafluoro-2-fluoro propyl acrylate, acrylic acid, methacrylic acid, octadecyl acrylate, hydroquinone uniformly to obtain a monomer composition; take α-methyl styrene, benzoyl peroxide, and dissolve them in propylene glycol methyl ether, heat to 70-80℃, drop the monomer composition, heat to 80-90℃, react for 3-4h, add modified epoxy resin, stir uniformly, react at 110℃ for 1-2h, cool to 50-55℃, add triethylamine, stir for 30-60min, remove the solvent, add water, and stir at high speed to obtain an epoxy / acrylic core-shell emulsion.

4. The method of claim 3, wherein the method further comprises: The epoxy / acrylic core-shell emulsion comprises the following raw materials in parts by mass: 12-15 parts of epoxy resin, 2-3 parts of phthalic anhydride, 0.04-0.06 parts of dimethyl ethylenediamine, 3-4 parts of decanoic acid, 0.8-1.5 parts of 2,2,3,3,3-pentafluoro-2-fluoro propyl acrylate, 3-4 parts of acrylic acid, 2-3 parts of methacrylic acid, 0.4-0.6 parts of octadecyl acrylate, 0.01-0.02 parts of hydroquinone, 1-2 parts of α-methyl styrene, 0.3-0.5 parts of benzoyl peroxide, 4-5 parts of propylene glycol methyl ether, 4-5 parts of triethylamine; and the amount of water added is 1.5-2 times the mass of the monomer composition.

5. The method of claim 1, wherein the method further comprises: The preparation of the hyperbranched polyurethane acrylate comprises the following steps: Polytetrahydrofuran diol is added into acetone and stirred uniformly, heated to 70-80℃, and then isophorone diisocyanate and dibutyl tin dilaurate are added, and stirred and reacted for 2-3h to obtain an isocyanate-terminated prepolymer; a chain extender is added, and reacted at 60-70℃ for 2-3h, and then hydroxyethyl methacrylate is added dropwise and stirred and reacted until the content of isocyanate groups in the system reaches the theoretical end point, and then acetone is removed by rotary evaporation to obtain the hyperbranched polyurethane acrylate.

6. The method of claim 1, wherein the method further comprises: The enhanced coating is coated on the surface of the lightweight packaging carton, and the single-side coating amount is 15-25 g / m 2 The curing process is: ultraviolet irradiation for 20-30 min, drying at 100-120 ℃ for 1-2 h.

7. A high-strength lightweight packaging carton prepared by the method according to any one of claims 1-6.

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