Waterproof heat-resistant color printing composite packaging paper and preparation method thereof

Abstract

The invention discloses waterproof heat-resistant color printing composite packaging paper and a preparation method thereof, and relates to the technical field of color printing composite packaging paper.The preparation method comprises the following steps that S1, aluminum foil is compounded to the two sides of a paperboard; s2, compounding color printing pages on the surfaces of aluminum foils on the two sides of the paperboard; s3, PVC films are compounded on the surfaces of the color printing pages on the two sides of the paperboard; s4, the surfaces of the PVC films on the two sides of the paperboard are coated with the waterproof and heat-resistant coating, heating is conducted to 80-85 DEG C, drying is conducted for 12-16 h, and the color printing composite packaging paper is obtained; the waterproof heat-resistant coating is prepared from non-isocyanate polythionocarbamate, POSS (Polyhedral Oligomeric Silsesquioxane)-tri-cyclic thiocarbonate and polyether amine; in the preparation process of the color printing composite packaging paper, adhesives are coated between the paperboard and the aluminum foil, between the aluminum foil and the color printing page and between the color printing page and the PVC film, and composite processing is conducted in a hot pressing mode.

Description

Technical Field

[0001] The invention relates to the technical field of color-printed composite packaging paper, in particular to waterproof and heat-resistant color-printed composite packaging paper and a preparation method thereof. Background Art

[0002] In recent years, with the diversification of consumer demand and the improvement of environmental awareness, the demand for high-performance and environmentally friendly packaging materials has gradually increased. Due to the limitations of its substrate and coating, traditional color-printed composite packaging paper often has problems with insufficient water resistance and heat resistance, and it is difficult to meet the requirements for packaging paper under high humidity and high temperature conditions. Although commonly used coating materials such as isocyanate polyurethane and polyhydroxy polyurethane have good mechanical properties and adhesion properties, they also have certain defects: the synthesis process of isocyanate requires the use of toxic phosgene, which poses a safety hazard; and polyhydroxy polyurethane is usually poor in water resistance due to the influence of the hydroxyl structure. At the same time, bisphenol A epoxy resin, as an important component of traditional epoxy resin, has potential health risks, forcing researchers to look for more environmentally friendly alternatives.

[0003] Therefore, it is of great significance to invent a waterproof and heat-resistant coating for color-printed composite packaging paper. Summary of the invention

[0004] The object of the present invention is to provide a waterproof and heat-resistant color-printed composite packaging paper and a preparation method thereof, so as to solve the problems raised in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for preparing waterproof and heat-resistant color-printed composite packaging paper: comprising the following steps S1: laminating aluminum foil on both sides of a paperboard;

[0007] S2: Compounding the color printed pages on the aluminum foil surfaces on both sides of the cardboard;

[0008] S3: Compounding the color printed pages on both sides of the cardboard with a PVC film;

[0009] S4: applying a waterproof and heat-resistant coating to the surface of the PVC film on both sides of the paperboard, heating to 80-85°C, and drying for 12-16 hours to obtain a color-printed composite packaging paper;

[0010] Furthermore, the waterproof and heat-resistant coating has a coating thickness of 20-30 μm;

[0011] Further, the waterproof and heat-resistant coating is prepared from non-isocyanate polythiourethane, POSS-tricyclic thiocarbonate and polyetheramine;

[0012] Furthermore, in the preparation process of the color-printed composite packaging paper, adhesive is coated between the paperboard and the aluminum foil, between the aluminum foil and the color-printed page, and between the color-printed page and the PVC film, and the composite processing is performed by hot pressing.

[0013] Furthermore, the adhesive includes ACTEbond ASB-908.

[0014] Furthermore, the preparation method of the waterproof and heat-resistant coating comprises the following steps: adding non-isocyanate polythiourethane and POSS-tricyclic thiocarbonate into a container, adding a catalyst solution, stirring evenly, adding a polyetheramine solution, stirring evenly, and obtaining a waterproof and heat-resistant coating.

[0015] Furthermore, in the preparation process of the waterproof and heat-resistant coating, the mass ratio of non-isocyanate polythiourethane:POSS-tricyclic thiocarbonate:polyetheramine is (2.0-3.49):(0.6-1.2):(1.4-2.21).

[0016] Furthermore, the solvents of the catalyst solution and the polyetheramine solution are both tetrahydrofuran;

[0017] Further, the catalyst solution concentration is 1wt%, and the catalyst is 1,8-diazobispiro[5.4.0]undec-7-ene;

[0018] Furthermore, the preparation method of the non-isocyanate polythiourethane comprises the following steps:

[0019] Add bio-based epoxy resin and lithium bromide to tetrahydrofuran, stir evenly, add carbon disulfide, stir and react for 48-72 hours under ice bath condition, rotary evaporate, wash with ethyl acetate and deionized water, and vacuum dry at 60-80°C for 48 hours to obtain non-isocyanate polythiourethane.

[0020] Furthermore, in the preparation process of the non-isocyanate polythiourethane, the molar ratio of bio-based epoxy resin: lithium bromide: carbon disulfide is 1:1:2.2.

[0021] Furthermore, the preparation method of the bio-based epoxy resin comprises the following steps:

[0022] Gallic acid, epichlorohydrin and tetrabutylammonium bromide are added to a reaction container, and a 20 wt % sodium hydroxide aqueous solution is added under stirring, and the mixture is heated to 100-105° C. and reacted for 4-4.5 hours. The solution is washed with deionized water until it is neutral, and dried by rotary evaporation to obtain a bio-based epoxy resin.

[0023] Furthermore, during the preparation of the bio-based epoxy resin, the molar ratio of gallic acid to epichlorohydrin is 1:20.

[0024] Furthermore, the preparation method of the POSS-tricyclic thiocarbonate comprises the following steps: step (1): adding phenyltrimethoxysilane, sodium hydroxide and deionized water to tetrahydrofuran, heating to 70-75°C for reaction for 4-4.5h, cooling to room temperature for reaction for 15-16h, rotary evaporation, and vacuum drying at 40-42°C for 24h to obtain heptaphenylsilsesquioxane trisodium silanol salt; adding heptaphenylsilsesquioxane trisodium silanol salt to tetrahydrofuran, adding dimethylchlorosilane under ice bath condition, heating to room temperature for reaction for 24h, filtering, rotary evaporation, adding methanol for precipitation, and vacuum drying the solid product at 40-42°C for 24h to obtain POSS-trihydrogen;

[0025] Step (2): POSS-3H and allyl glycidyl ether are added to toluene, purged with nitrogen for 30-45 min, Karstedt catalyst is added, heated to 90-92° C. for reaction for 36-48 h, cooled to room temperature, rotary evaporated, the product is extracted with dichloromethane, and vacuum dried at 40-42° C. for 48 h to obtain POSS-triepoxide;

[0026] Step (3): Add POSS-triepoxide and lithium bromide to tetrahydrofuran, stir evenly, add carbon disulfide, stir and react in an ice bath for 24-48 hours, rotary evaporate, wash with ethyl acetate and deionized water, extract the product with dichloromethane, and vacuum dry at 40-42° C. for 48 hours to obtain POSS-tricyclic thiocarbonate.

[0027] Furthermore, in the preparation process of the POSS-trihydrogen, the proportions of the components by mass include: 45-50 parts of phenyltrimethoxysilane, 0.96-1.04 parts of sodium hydroxide, 5.26-5.54 parts of deionized water, and 27.79-28.12 parts of dimethylchlorosilane;

[0028] Furthermore, in the preparation process of the POSS-triepoxide compound, the proportions of the components by mass include: 10-12.44 parts of POSS-3H, 6.16-6.36 parts of allyl glycidyl ether, and 0.03-0.04 parts of Karstedt catalyst;

[0029] Furthermore, in the preparation process of the POSS-tricyclic thiocarbonate, the molar ratio of POSS-triepoxide: lithium bromide: carbon disulfide is 1:1:2.2.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The present invention uses non-isocyanate polythiourethane, POSS-tricyclic thiocarbonate and polyetheramine as raw materials to prepare a coating with excellent waterproof and fire-resistant properties to meet the needs of waterproof and heat-resistant properties of color-printed composite packaging paper. Different from traditional isocyanate polyurethane and polyhydroxy polyurethane, the non-isocyanate polythiourethane prepared by the present invention does not have the safety hazard of toxic phosgene in the isocyanate synthesis process of traditional isocyanate polyurethane raw materials, nor does it have the problem of poor waterproof performance caused by a large number of hydroxyl groups in the polyhydroxy polyurethane structure. Using gallic acid, a natural renewable resource, as a raw material, a bio-based epoxy resin containing four epoxy groups is prepared by epoxidation treatment, aiming to replace traditional bisphenol A epoxy resin and develop a more environmentally friendly and healthier alternative to isocyanate polyurethane and polyhydroxy polyurethane.

[0032] 2. Different from the slow conversion rate and incomplete conversion of the pentacyclic carbonate hanging energy groups of the epoxy resin in the preparation process of polyhydroxy polyurethane, which leads to incomplete curing, long curing time and low degree of crosslinking of the coating during the subsequent coating curing process; the present invention converts the epoxy groups in the epoxy resin into pentacyclic dithiocarbonates through the fixing effect of carbon disulfide, and then reacts with amino groups to form thiocarbamates. Since the pentacyclic dithiocarbonates have larger and more favorable ring strain, they are more reactive to nucleophiles than the oxygen analogue pentacyclic carbonates, which enables the reaction to proceed relatively quickly under milder conditions, greatly improving the crosslinking density and curing rate.

[0033] 3. The present invention introduces homemade POSS-tricyclic thiocarbonate into the coating, which, on the one hand, improves the waterproof and heat-resistant properties of the coating; on the other hand, due to the polyepoxy groups of gallic acid epoxy resin and the polyamino structure of polyetheramine, the coating curing process has a higher cross-linking density. The addition of POSS-tricyclic thiocarbonate can greatly improve the toughness of the coating, thereby achieving the purpose of enhancing toughness, tensile strength and glass transition temperature. DETAILED DESCRIPTION

[0034] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] In the following examples, the bisphenol A epoxy resin specification is E51, purchased from Hangzhou Wuhuigang Adhesive Co., Ltd.; the cardboard specification is kraft paper, purchased from Nine Dragons Paper; the aluminum foil is purchased from Shandong Zhongfo Aluminum Technology Co., Ltd.; the PVC film specification: thickness is 0.30 mm, purchased from Foshan Bo Na Cai Decoration Materials Co., Ltd.; the remaining raw materials are commercially available.

[0036] In the following embodiments, the method for preparing the bio-based epoxy resin comprises the following steps:

[0037] 1 mol of gallic acid, 20 mol of epichlorohydrin and 0.4 g of tetrabutylammonium bromide were added to a reaction container, 20 wt% sodium hydroxide aqueous solution was added under stirring, the mixture was heated to 100° C. and reacted for 4 h, the solution was washed with deionized water until neutral, and rotary evaporated to obtain a bio-based epoxy resin.

[0038] In the following examples, the method for preparing the non-isocyanate polythiourethane comprises the following steps:

[0039] 1 mol of bio-based epoxy resin and 1 mol of lithium bromide were added to 50 mL of tetrahydrofuran, stirred evenly, and 2.2 mol of carbon disulfide was added. The mixture was stirred and reacted for 48 h in an ice bath. The mixture was rotary evaporated, washed with ethyl acetate and deionized water, and dried in vacuo at 80° C. for 48 h to obtain non-isocyanate polythiourethane.

[0040] In the following embodiment, the preparation method of the POSS-tricyclic thiocarbonate comprises the following steps: step (1): adding 45 parts of phenyltrimethoxysilane, 0.96 parts of sodium hydroxide and 5.26 parts of deionized water to 250 mL of tetrahydrofuran, heating to 70° C. for reaction for 4 hours, cooling to room temperature for reaction for 15 hours, rotary evaporation, and vacuum drying at 4° C. for 24 hours to obtain heptaphenylsilsesquioxane trisodium silanol salt; adding heptaphenylsilsesquioxane trisodium silanol salt to tetrahydrofuran, adding 27.79 parts of dimethylchlorosilane under ice bath condition, heating to room temperature for reaction for 24 hours, filtering, rotary evaporation, adding methanol for precipitation, and vacuum drying the solid product at 40° C. for 24 hours to obtain POSS-trihydrogen;

[0041] Step (2): add 10 parts of POSS-3H and 6.16 parts of allyl glycidyl ether to 100 mL of toluene, purge with nitrogen for 30 min, add 0.03 parts of Karstedt catalyst, heat to 90° C. for reaction for 36 h, cool to room temperature, rotary evaporate, extract the product with dichloromethane, and vacuum dry at 40° C. for 48 h to obtain POSS-triepoxide;

[0042] Step (3): add 1 mol POSS-triepoxide and 1 mol lithium bromide to tetrahydrofuran, stir evenly, add 2.2 mol carbon disulfide, stir and react for 24 hours in an ice bath, rotary evaporate, wash with ethyl acetate and deionized water, extract the product with dichloromethane, and vacuum dry at 40°C for 48 hours to obtain POSS-tricyclic thiocarbonate.

[0043] Example 1: A method for preparing a waterproof and heat-resistant color-printed composite packaging paper: S1: Laminating aluminum foil on both sides of a paperboard;

[0044] S2: Compounding the color printed pages on the aluminum foil surfaces on both sides of the cardboard;

[0045] S3: Compounding the color printed pages on both sides of the cardboard with a PVC film;

[0046] S4: 2 g of non-isocyanate polythiourethane and 0.6 g of POSS-tricyclic thiocarbonate are added to a container, a tetrahydrofuran solution containing 0.05 g of 1,8-diazobispiro[5.4.0]undec-7-ene is added, and the mixture is stirred evenly. A tetrahydrofuran solution containing 1.4 g of polyetheramine is added, and the mixture is stirred evenly to obtain a waterproof and heat-resistant coating;

[0047] S5: Apply a waterproof and heat-resistant coating to the surface of the PVC film on both sides of the cardboard with a coating thickness of 20 μm, heat to 80° C., and dry for 12 hours to obtain a color-printed composite packaging paper.

[0048] Example 2: A method for preparing a waterproof and heat-resistant color-printed composite packaging paper: S1: Laminating aluminum foil on both sides of a paperboard;

[0049] S2: Compounding the color printed pages on the aluminum foil surfaces on both sides of the cardboard;

[0050] S3: Compounding the color printed pages on both sides of the cardboard with a PVC film;

[0051] S4: 2.78 g of non-isocyanate polythiourethane and 0.96 g of POSS-tricyclic thiocarbonate are added to a container, a tetrahydrofuran solution containing 0.06 g of 1,8-diazobispiro[5.4.0]undec-7-ene is added, and the mixture is stirred evenly, and a tetrahydrofuran solution containing 1.78 g of polyetheramine is added, and the mixture is stirred evenly to obtain a waterproof and heat-resistant coating;

[0052] S5: Apply a waterproof and heat-resistant coating to the surface of the PVC film on both sides of the cardboard with a coating thickness of 20 μm, heat to 80° C., and dry for 12 hours to obtain a color-printed composite packaging paper.

[0053] Example 3: A method for preparing a waterproof and heat-resistant color-printed composite packaging paper: S1: Laminating aluminum foil on both sides of a paperboard;

[0054] S2: Compounding the color printed pages on the aluminum foil surfaces on both sides of the cardboard;

[0055] S3: Compounding the color printed pages on both sides of the cardboard with a PVC film;

[0056] S4: 3.49 g of non-isocyanate polythiourethane and 1.2 g of POSS-tricyclic thiocarbonate are added to a container, a tetrahydrofuran solution containing 0.06 g of 1,8-diazobispiro[5.4.0]undec-7-ene is added, and the mixture is stirred evenly, and a tetrahydrofuran solution containing 2.21 g of polyetheramine is added, and the mixture is stirred evenly to obtain a waterproof and heat-resistant coating;

[0057] S5: Apply a waterproof and heat-resistant coating to the surface of the PVC film on both sides of the cardboard with a coating thickness of 20 μm, heat to 80° C., and dry for 12 hours to obtain a color-printed composite packaging paper.

[0058] Comparative Example 1: A method for preparing a waterproof and heat-resistant color-printed composite packaging paper: The method for preparing the non-isocyanate polythiourethane comprises the following steps:

[0059] 1 mol of bisphenol A epoxy resin and 1 mol of lithium bromide were added to 50 mL of tetrahydrofuran, stirred evenly, and 2.2 mol of carbon disulfide was added. The mixture was stirred and reacted for 48 h under ice bath conditions, and then rotary evaporated, washed with ethyl acetate and deionized water, and dried under vacuum at 80° C. for 48 h to obtain non-isocyanate polythiourethane.

[0060] S1: Laminate aluminum foil on both sides of the cardboard;

[0061] S2: Compounding the color printed pages on the aluminum foil surfaces on both sides of the cardboard;

[0062] S3: Compounding the color printed pages on both sides of the cardboard with a PVC film;

[0063] S4: 2 g of non-isocyanate polythiourethane and 0.6 g of POSS-tricyclic thiocarbonate are added to a container, a tetrahydrofuran solution containing 0.05 g of 1,8-diazobispiro[5.4.0]undec-7-ene is added, and the mixture is stirred evenly. A tetrahydrofuran solution containing 1.4 g of polyetheramine is added, and the mixture is stirred evenly to obtain a waterproof and heat-resistant coating;

[0064] S5: Apply a waterproof and heat-resistant coating to the surface of the PVC film on both sides of the cardboard with a coating thickness of 20 μm, heat to 80° C., and dry for 12 hours to obtain a color-printed composite packaging paper.

[0065] Comparative Example 2: A method for preparing a waterproof and heat-resistant color-printed composite packaging paper: The method for preparing the non-isocyanate polythiourethane comprises the following steps:

[0066] 10 g of bio-based epoxy resin was added to N,N-dimethylformamide, and 2.38 g of tetra-n-butylammonium bromide was added, and the mixture was heated to 80°C, and carbon dioxide was introduced. The mixture was kept warm for 80 hours, and then washed with vinyl acetate and deionized water, and the mixture was rotary evaporated at 60°C and vacuum dried at 80°C to obtain polyhydroxy polyurethane.

[0067] S1: Laminate aluminum foil on both sides of the cardboard;

[0068] S2: Compounding the color printed pages on the aluminum foil surfaces on both sides of the cardboard;

[0069] S3: Compounding the color printed pages on both sides of the cardboard with a PVC film;

[0070] S4: 2 g of polyhydroxy polyurethane and 0.6 g of POSS-tricyclic thiocarbonate are added to a container, a tetrahydrofuran solution containing 0.05 g of 1,8-diazobispiro[5.4.0]undec-7-ene is added, and the mixture is stirred evenly, and a tetrahydrofuran solution containing 1.4 g of polyetheramine is added, and the mixture is stirred evenly to obtain a waterproof and heat-resistant coating;

[0071] S5: Apply a waterproof and heat-resistant coating to the surface of the PVC film on both sides of the cardboard with a coating thickness of 20 μm, heat to 80° C., and dry for 12 hours to obtain a color-printed composite packaging paper.

[0072] Comparative Example 3: A method for preparing a waterproof and heat-resistant color-printed composite packaging paper: The method for preparing the POSS-tricyclic thiocarbonate comprises the following steps: Step (1): adding 45 parts of phenyltrimethoxysilane, 0.96 parts of sodium hydroxide, and 5.26 parts of deionized water to 250 mL of tetrahydrofuran, heating to 70° C. for reaction for 4 hours, cooling to room temperature for reaction for 15 hours, rotary evaporation, and vacuum drying at 4° C. for 24 hours to obtain heptaphenylsilsesquioxane trisodium silanol salt; adding heptaphenylsilsesquioxane trisodium silanol salt to tetrahydrofuran, adding 27.79 parts of dimethylchlorosilane under ice bath conditions, heating to room temperature for reaction for 24 hours, filtering, rotary evaporation, adding methanol for precipitation, and placing the solid product under 40° C. environment for vacuum drying for 24 hours to obtain POSS-trihydrogen;

[0073] Step (2): add 10 parts of POSS-3H and 6.16 parts of allyl glycidyl ether to 100 mL of toluene, purge with nitrogen for 30 min, add 0.03 parts of Karstedt catalyst, heat to 90° C. for reaction for 36 h, cool to room temperature, rotary evaporate, extract the product with dichloromethane, and vacuum dry at 40° C. for 48 h to obtain POSS-triepoxide;

[0074] Step (3): 13 g of POSS-triepoxide, 0.5 g of tetra-n-butylammonium iodide, 0.45 g of 1,3-bis(hexafluoro-2-hydroxyisopropyl)benzene and 15 mL of anhydrous toluene are introduced with nitrogen, heated to 80° C., the pressure is increased to 6 MPa, the reaction is carried out for 48 h, and after cooling to room temperature, the solvent is removed and extracted with dichloromethane to obtain POSS-trihydroxy polyurethane.

[0075] S1: Laminate aluminum foil on both sides of the cardboard;

[0076] S2: Compounding the color printed pages on the aluminum foil surfaces on both sides of the cardboard;

[0077] S3: Compounding the color printed pages on both sides of the cardboard with a PVC film;

[0078] S4: 2 g of polyhydroxy polyurethane and 0.6 g of POSS-trihydroxy polyurethane are added into a container, a tetrahydrofuran solution containing 0.05 g of 1,8-diazobisspiro[5.4.0]undec-7-ene is added, and the mixture is stirred evenly, and a tetrahydrofuran solution containing 1.4 g of polyetheramine is added, and the mixture is stirred evenly to obtain a waterproof and heat-resistant coating;

[0079] S5: Apply a waterproof and heat-resistant coating to the surface of the PVC film on both sides of the cardboard with a coating thickness of 20 μm, heat to 80° C., and dry for 12 hours to obtain a color-printed composite packaging paper.

[0080] Comparative Example 4: A method for preparing a waterproof and heat-resistant color-printed composite packaging paper: S1: Laminating aluminum foil on both sides of a paperboard;

[0081] S2: Compounding the color printed pages on the aluminum foil surfaces on both sides of the cardboard;

[0082] S3: Compounding the color printed pages on both sides of the cardboard with a PVC film;

[0083] S4: 4.22 g of non-isocyanate polythiourethane and 0.6 g of POSS-tricyclic thiocarbonate are added to a container, a tetrahydrofuran solution containing 0.05 g of 1,8-diazobispiro[5.4.0]undec-7-ene is added, and the mixture is stirred evenly, and a tetrahydrofuran solution containing 1.4 g of polyetheramine is added, and the mixture is stirred evenly to obtain a waterproof and heat-resistant coating;

[0084] S5: Apply a waterproof and heat-resistant coating to the surface of the PVC film on both sides of the cardboard with a coating thickness of 20 μm, heat to 80° C., and dry for 12 hours to obtain a color-printed composite packaging paper.

[0085] Comparative Example 5: A method for preparing a waterproof and heat-resistant color-printed composite packaging paper: S1: Laminating aluminum foil on both sides of a paperboard;

[0086] S2: Compounding the color printed pages on the aluminum foil surfaces on both sides of the cardboard;

[0087] S3: Compounding the color printed pages on both sides of the cardboard with a PVC film;

[0088] S4: 2 g of non-isocyanate polythiourethane and 0.4 g of POSS-tricyclic thiocarbonate are added to a container, a tetrahydrofuran solution containing 0.05 g of 1,8-diazobispiro[5.4.0]undec-7-ene is added, and the mixture is stirred evenly, and a tetrahydrofuran solution containing 1.4 g of polyetheramine is added, and the mixture is stirred evenly to obtain a waterproof and heat-resistant coating;

[0089] S5: Apply a waterproof and heat-resistant coating to the surface of the PVC film on both sides of the cardboard with a coating thickness of 20 μm, heat to 80° C., and dry for 12 hours to obtain a color-printed composite packaging paper.

[0090] Experiment: Water absorption test: The color-printed composite packaging paper samples of the above embodiment and comparative example were immersed in deionized water, soaked at room temperature for 72 hours, taken out, the surface water stains were wiped off, the samples were weighed, and the water absorption was calculated;

[0091] Water absorption rate (%) = weight after immersion - weight before immersion / weight before immersion × 100%.

[0092] The waterproof and heat-resistant coatings prepared in the above examples and comparative examples were coated on a polytetrafluoroethylene plate to prepare coating samples of 30×5×1 mm for mechanical property testing.

[0093] Mechanical properties test: The tensile test was carried out at room temperature using a universal testing machine at a tensile rate of 130 mm / min.

[0094] Glass transition temperature test: The glass transition temperature of the coating sample is measured by dynamic mechanical thermal analysis.

[0095] The experimental data are shown in Table 1 below.

[0096] Table 1 Performance test data table

[0097] Water absorption / % Tensile strength / MPa Glass transition temperature / ℃ Example 1 3.1 28.1 51.2 Example 2 2.4 31.6 53.5 Example 3 1.8 33.5 56.1 Comparative Example 1 6.4 24.1 43.2 Comparative Example 2 5.6 25.7 45.6 Comparative Example 3 5.1 26.5 48.1 Comparative Example 4 3.5 22.1 48.5 Comparative Example 5 4.9 24.6 44.9

[0098] Conclusion: The waterproof and heat-resistant coating prepared by the present invention has excellent waterproof and heat-resistant properties, and the color-printed composite packaging paper prepared using the coating also has excellent waterproof and heat-resistant properties.

[0099] In Comparative Example 1, traditional bisphenol A epoxy resin is used to replace bio-based epoxy resin, resulting in lower water absorption, tensile strength, and glass transition temperature; in Comparative Example 2, polyhydroxy polyurethane is used to replace non-isocyanate polythiourethane, resulting in lower performance; in Comparative Example 3, POSS-trihydroxy polyurethane is used to replace POSS-tricyclic thiocarbonate, resulting in lower performance; in Comparative Example 4, the increase in non-isocyanate polythiourethane leads to an increase in crosslinking density and lower performance; in Comparative Example 5, the content of POSS-tricyclic thiocarbonate is reduced, resulting in lower performance.

[0100] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and scope of the equivalent elements of the claims be included in the invention. Any marking in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for preparing a waterproof and heat-resistant color-printed composite packaging paper, characterized in that: The following steps are involved: S1: Laminate aluminum foil on both sides of the cardboard; S2: Compounding the color printed pages on the aluminum foil surfaces on both sides of the cardboard; S3: Compounding the color printed pages on both sides of the cardboard with a PVC film; S4: applying a waterproof and heat-resistant coating to the surface of the PVC film on both sides of the paperboard, heating to 80-85°C, and drying for 12-16 hours to obtain a color-printed composite packaging paper; The waterproof and heat-resistant coating has a coating thickness of 20-30 μm; The waterproof and heat-resistant coating is prepared from non-isocyanate polythiourethane, POSS-tricyclic thiocarbonate and polyetheramine; During the preparation of the color-printed composite packaging paper, adhesive is coated between the paperboard and the aluminum foil, between the aluminum foil and the color-printed page, and between the color-printed page and the PVC film, and the composite is performed by hot pressing.

2. The method for preparing a waterproof and heat-resistant color-printed composite packaging paper according to claim 1, characterized in that: The preparation method of the waterproof and heat-resistant coating comprises the following steps: adding non-isocyanate polythiourethane and POSS-tricyclic thiocarbonate into a container, adding a catalyst solution, stirring evenly, adding a polyetheramine solution, stirring evenly, and obtaining the waterproof and heat-resistant coating.

3. The method for preparing a waterproof and heat-resistant color-printed composite packaging paper according to claim 2, characterized in that: In the preparation process of the waterproof and heat-resistant coating, the mass ratio of non-isocyanate polythiourethane:POSS-tricyclic thiocarbonate:polyetheramine is (2.0-3.49):(0.6-1.2):(1.4-2.21).

4. The method for preparing a waterproof and heat-resistant color-printed composite packaging paper according to claim 2, characterized in that: The preparation method of the non-isocyanate polythiourethane comprises the following steps: Add bio-based epoxy resin and lithium bromide to tetrahydrofuran, stir evenly, add carbon disulfide, stir and react for 48-72 hours under ice bath condition, rotary evaporate, wash with ethyl acetate and deionized water, and vacuum dry at 60-80°C for 48 hours to obtain non-isocyanate polythiourethane.

5. The method for preparing a waterproof and heat-resistant color-printed composite packaging paper according to claim 4, characterized in that: During the preparation of the non-isocyanate polythiourethane, the molar ratio of bio-based epoxy resin: lithium bromide: carbon disulfide was 1:1:2.

2.

6. The method for preparing a waterproof and heat-resistant color-printed composite packaging paper according to claim 4, characterized in that: The preparation method of the bio-based epoxy resin comprises the following steps: Gallic acid, epichlorohydrin and tetrabutylammonium bromide are added to a reaction container, and a 20 wt % sodium hydroxide aqueous solution is added under stirring, and the mixture is heated to 100-105° C. and reacted for 4-4.5 hours. The solution is washed with deionized water until it is neutral, and dried by rotary evaporation to obtain a bio-based epoxy resin.

7. The method for preparing a waterproof and heat-resistant color-printed composite packaging paper according to claim 6, characterized in that: During the preparation of bio-based epoxy resin, the molar ratio of gallic acid:epichlorohydrin was 1:

20.

8. The method for preparing a waterproof and heat-resistant color-printed composite packaging paper according to claim 2, characterized in that: The preparation method of the POSS-tricyclic thiocarbonate comprises the following steps: step (1): adding phenyltrimethoxysilane, sodium hydroxide and deionized water to tetrahydrofuran, heating to 70-75°C for reaction for 4-4.5h, cooling to room temperature for reaction for 15-16h, rotary evaporation, and vacuum drying at 40-42°C for 24h to obtain heptaphenylsilsesquioxane trisodium silanol salt; adding heptaphenylsilsesquioxane trisodium silanol salt to tetrahydrofuran, adding dimethylchlorosilane under ice bath condition, heating to room temperature for reaction for 24h, filtering, rotary evaporation, adding methanol for precipitation, and placing the solid product under 40-42°C environment for vacuum drying for 24h to obtain POSS-trihydrogen; Step (2): POSS-3H and allyl glycidyl ether are added to toluene, purged with nitrogen for 30-45 min, Karstedt catalyst is added, heated to 90-92° C. for reaction for 36-48 h, cooled to room temperature, rotary evaporated, the product is extracted with dichloromethane, and vacuum dried at 40-42° C. for 48 h to obtain POSS-triepoxide; Step (3): Add POSS-triepoxide and lithium bromide to tetrahydrofuran, stir evenly, add carbon disulfide, stir and react in an ice bath for 24-48 hours, rotary evaporate, wash with ethyl acetate and deionized water, extract the product with dichloromethane, and vacuum dry at 40-42° C. for 48 hours to obtain POSS-tricyclic thiocarbonate.

9. The method for preparing a waterproof and heat-resistant color-printed composite packaging paper according to claim 8, characterized in that: In the preparation process of POSS-trihydrogen, the proportions of each component by mass include: 45-50 parts of phenyltrimethoxysilane, 0.96-1.04 parts of sodium hydroxide, 5.26-5.54 parts of deionized water, and 27.79-28.12 parts of dimethylchlorosilane; in the preparation process of POSS-triepoxide, the proportions of each component by mass include: 10-12.44 parts of POSS-3H, 6.16-6.36 parts of allyl glycidyl ether, and 0.03-0.04 parts of Karstedt catalyst; in the preparation process of POSS-tricyclic thiocarbonate, the molar ratio of POSS-triepoxide: lithium bromide: carbon disulfide is 1:1:2.

2.

10. The color-printed composite packaging paper prepared according to the method for preparing a waterproof and heat-resistant color-printed composite packaging paper according to any one of claims 1 to 9.