A highly water-resistant environmentally friendly emulsion for paper-based packaging materials, and its preparation method and application

Abstract

The present invention relates to the technical field of modified emulsions and packaging materials, and specifically to a highly water-resistant environmentally friendly emulsion for paper-based packaging materials, and a preparation method and application thereof. The preparation method uses isooctyl acrylate, lauryl methacrylate, styrene and methacrylic acid as reaction monomers, silicone coupling agent KH151 as a modifier, and heptadecanol polyoxyethylene ether monophosphate as an emulsifier, and heats and emulsifies to obtain a pre-emulsion, and then the pre-emulsion is polymerized with an initiator, ammonium persulfate, and glycerol triglycidyl ether is used as a post-crosslinking agent, and a base is used as a catalyst to perform a crosslinking reaction to obtain a highly water-resistant environmentally friendly emulsion for paper-based packaging materials. The preparation method is green and environmentally friendly, and the prepared emulsion has the advantages of good emulsification performance, excellent water-resistant performance, and significantly low toxicity and low irritation, and is therefore suitable for the application of water-resistant coatings for paper-based packaging materials.

Description

Technical Field

[0001] The invention relates to the technical field of modified emulsions and packaging materials, and in particular to a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials, and a preparation method and application thereof. Background Art

[0002] Among the four pillar packaging materials of paper, plastic, metal and glass, paper products have the fastest growth. Paper is the cheapest and can be recycled or used as plant fertilizer, and can also purify the environment. Paper is mainly composed of natural plant fibers, which are connected to each other by hydrogen bonds. Due to their hydrophilicity and porosity, paper and paperboard materials usually have strong liquid absorption, which greatly limits the use of paper-based materials in the packaging field. This has become a problem to be solved in this field - how to improve the water barrier of paper-based packaging materials.

[0003] At present, among all the methods to improve the water barrier properties of packaging materials, surface coating of water barrier coating materials is the easiest to achieve, with a simple process and relatively low production cost. Among them, water-based styrene acrylic emulsion, as a typical basic raw material for environmentally friendly coatings, has the advantages of low toxicity, low price, and good adhesion performance, and can be used for special treatment of paper-based materials. However, traditional water-based styrene acrylic emulsions have the problems of poor water resistance and easy cracking of film formation, which is not conducive to the use of water barrier coatings for paper-based packaging materials. Among them, the surface energy of silicone is lower than that of other substances, which makes it have good hydrophobic and water-blocking properties. Introducing it into water-based styrene acrylic emulsion will improve the water resistance of the emulsion.

[0004] In the prior art, organosilicon is used to chemically modify styrene-acrylic emulsion to prepare organosilicon styrene-acrylic resin with better comprehensive performance than styrene-acrylic resin. The good hydrophobic and water-blocking properties of organosilicon will improve the water resistance of the product. It is reported that Wang Dongliang et al. used styrene and isooctyl acrylate as monomers, KH-570 and KH-602 as silane coupling agents, potassium persulfate as initiator, polyoxyethylene octylphenol ether-10 (OP-10) and sodium dodecyl sulfate (SDS) as composite emulsifiers, and adopted semi-continuous emulsion polymerization process to synthesize a modified styrene-acrylic emulsion with low water absorption and good water resistance. In addition, there is also an existing technology that uses butyl acrylate (BA), methyl methacrylate (MMA), styrene (St) and acrylic acid (AA) as reaction monomers, and uses hydroxy silicone oil (SO) and 3-mercaptopropylmethyldimethoxysilane (MPDMS) to prepare mercapto-containing organosilicon (PMMS) as a modifier, and prepares a series of organosilicon-modified water-based styrene-acrylic composite emulsions through seed emulsion polymerization. However, the organosilicon macromolecular modifier containing mercapto groups prepared by hydroxy silicone oil and 3-mercaptopropylmethyldimethoxysilane used in the prior art requires the use of organic solvents such as dimethylbenzene, which not only increases the synthesis cost, but also the use of organic solvents is not conducive to environmental protection. In addition, the water-blocking modified emulsions in the prior art often use polyoxyethylene octylphenol ether-10 (OP-10) and sodium dodecyl sulfate (SDS) as composite emulsifiers, which has the defect of poor emulsification effect.

[0005] At present, the water absorption value of paper products prepared by using modified styrene-acrylic emulsion prepared by existing technology is generally 10g / m 2 The water absorption value is still relatively large. Therefore, when the water-blocking modified latex in the prior art is applied to paper base, the water absorption rate is still relatively high, and the water-blocking performance needs to be further improved. Summary of the invention

[0006] In order to overcome the shortcomings of the prior art, the first object of the present invention is to provide a method for preparing a highly water-barrier environmentally friendly emulsion for paper-based packaging materials. The preparation method has the advantages of good emulsification effect, environmental protection and mild conditions, and can form a tight network structure, greatly improving the water-barrier performance of the emulsion.

[0007] The second object of the present invention is to provide a highly water-barrier environmentally friendly emulsion for paper-based packaging materials, wherein the emulsion has the characteristic of excellent water-barrier performance.

[0008] The third object of the present invention is to provide an application of a highly water-resistant and environmentally friendly emulsion in paper-based packaging materials.

[0009] The fourth object of the present invention is to provide a paper-based packaging material, which uses a high water-barrier environmentally friendly emulsion and has the advantages of excellent water-barrier performance and being green and environmentally friendly.

[0010] In order to achieve the first object of the above invention, the technical solution adopted by the present invention is as follows:

[0011] The invention provides a method for preparing a highly water-resistant environmentally friendly emulsion for paper-based packaging materials. The method comprises the following steps: using isooctyl acrylate, lauryl methacrylate, styrene and methacrylic acid as reaction monomers, an organosilicon coupling agent KH151 as a modifier and heptadecanol polyoxyethylene ether monophosphate as an emulsifier, performing heating and emulsification to obtain a pre-emulsion, then performing a polymerization reaction on the pre-emulsion and an initiator ammonium persulfate, and performing a cross-linking reaction using glycerol triglycidyl ether as a post-crosslinking agent and a base as a catalyst to obtain the highly water-resistant environmentally friendly emulsion for paper-based packaging materials.

[0012] The present invention discloses a method for preparing a highly water-blocking environmentally friendly emulsion for paper-based packaging materials. Since lauryl methacrylate is selected as a monomer, and lauryl methacrylate is a monomer with a long hydrophobic alkyl chain, the structure obtained after polymerization and cross-linking reaction of the monomer has the characteristics of excellent water-blocking performance. In addition, the present invention uses glycerol triglycidyl ether as a post-crosslinking agent to carry out a cross-linking reaction, which can transform the linear polymer obtained by the polymerization reaction into a tighter network structure, thereby further improving the water-blocking performance of the emulsion product. In addition, the present invention uses heptadecanol polyoxyethylene ether monophosphate as an emulsifier, which not only greatly improves the emulsifying performance compared to the commonly used composite emulsifiers in the prior art, but also has significantly low toxicity and low irritation, and is suitable for the preparation of coatings for paper-based packaging materials.

[0013] Furthermore, the mass ratio of isooctyl acrylate, lauryl methacrylate, styrene, methacrylic acid, silicone coupling agent KH151, and heptadecanol polyoxyethylene ether monophosphate is (5-10): (25-30): (18-25): (4-10): (1-2): (1-3); and / or

[0014] The amount of glycerol triglycidyl ether used is 0.3% to 1% of the mass of the pre-emulsion; and / or

[0015] The amount of the catalyst used is 0.2% to 0.6% of the mass of the pre-emulsion.

[0016] Furthermore, in the cross-linking reaction, the catalyst is one or a combination of two or more of ammonia water, sodium hydroxide or potassium hydroxide; and / or

[0017] After the cross-linking reaction is completed, alkali is added to adjust the pH value of the emulsion to 9-10; the alkali is one or a combination of two or more of ammonia water, sodium hydroxide or potassium hydroxide.

[0018] Furthermore, the method for preparing the highly water-resistant and environmentally friendly emulsion for paper-based packaging materials comprises the following steps:

[0019] S1, pre-emulsification: adding an aqueous solution of an emulsifier, heptadecanol polyoxyethylene ether monophosphate, into a reactor, heating, adding a mixed solution of methacrylic acid, styrene, isooctyl acrylate, lauryl methacrylate and silicone coupling agent KH151 into the reactor, stirring and emulsifying, to obtain a pre-emulsified solution;

[0020] S2, polymerization reaction: adding part of the pre-emulsion obtained in S1 and part of the initiator ammonium persulfate solution into another reactor, and carrying out polymerization reaction under heating and constant temperature stirring;

[0021] S3, cross-linking reaction: continue to add the remaining pre-emulsion and the initiator ammonium persulfate solution to the reactor of step S2, and when the pre-emulsion remains 20% to 40%, add the post-cross-linking agent glycerol triglycidyl ether and the base to carry out a cross-linking reaction, then keep the temperature and then cool down to obtain an emulsion;

[0022] S4, adjusting the pH value: adding alkali to the emulsion obtained in step S3 to adjust the pH value to 9-10, thereby obtaining the highly water-resistant and environmentally friendly emulsion for paper-based packaging materials.

[0023] Among them, in the polymerization reaction of step S2, the polymerization method adopts the seed emulsion polymerization method, firstly, a polymerization reaction is carried out through part of the pre-emulsion and part of the initiator ammonium persulfate solution to form a latex micelle-like seed, and then the chain length is further increased on the seed through the cross-linking reaction in step S3 to form a network structure. In addition, when the pre-emulsion has 20% to 40% remaining, the post-cross-linking agent propylene triglycidyl ether and the base are added to carry out the cross-linking reaction, so as to be able to cross-link on the basis of the already formed polymer, so as to form a tighter network structure, so as to further improve the water-blocking performance of the product structure.

[0024] In the above technical solution, in step S1, the heating temperature is 75°C to 85°C; the concentration of the aqueous solution of heptadecanol polyoxyethylene ether monophosphate is 0.03g / mL to 0.08g / mL.

[0025] In the above technical solution, the polymerization reaction temperature is 75°C to 85°C, and the polymerization reaction time is 20min to 40min; and / or

[0026] The temperature of the cross-linking reaction is 75° C. to 85° C., and the time of the cross-linking reaction is 1.5 h to 2 h; and / or

[0027] The concentration of the ammonium persulfate solution is 0.05 g / mL to 0.15 g / mL.

[0028] In the above technical solution, the mass of the pre-emulsion added to the polymerization reaction in step S2 accounts for 5% to 10% of the total mass of the pre-emulsion; and / or

[0029] The mass of the ammonium persulfate solution added to the polymerization reaction in step S2 accounts for 5% to 10% of the total mass of the ammonium persulfate solution; and / or

[0030] In the step S3, the heat preservation time is 50 min to 70 min; and the temperature is lowered to 40 to 50°C.

[0031] In order to achieve the second purpose of the above invention, the technical solution adopted by the present invention is as follows:

[0032] The present invention provides a highly water-resistant environmentally friendly emulsion for paper-based packaging materials, which is prepared by the above-mentioned method for preparing a highly water-resistant environmentally friendly emulsion for paper-based packaging materials. The highly water-resistant environmentally friendly emulsion for paper-based packaging materials has the characteristics of excellent water-resistant performance.

[0033] In order to achieve the third purpose of the above invention, the technical solution adopted by the present invention is as follows:

[0034] The present invention provides an application of a highly water-resistant environmentally friendly emulsion in a paper-based packaging material. The highly water-resistant environmentally friendly emulsion is prepared by the above-mentioned method for preparing a highly water-resistant environmentally friendly emulsion for a paper-based packaging material.

[0035] In order to achieve the fourth object of the above invention, the technical solution adopted by the present invention is as follows:

[0036] The present invention provides a paper-based packaging material, wherein the high water-blocking environmentally friendly emulsion prepared by the above-mentioned method for preparing a high water-blocking environmentally friendly emulsion for paper-based packaging material is coated on a substrate paper and dried to prepare the paper-based packaging material.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] (1) The method for preparing a highly water-resistant environmentally friendly emulsion for paper-based packaging materials of the present invention comprises the following steps: using isooctyl acrylate, lauryl methacrylate, styrene and methacrylic acid as reaction monomers, silicone coupling agent KH151 as a modifier, and heptadecanol polyoxyethylene ether monophosphate as an emulsifier, heating and emulsifying to obtain a pre-emulsion, and then subjecting the pre-emulsion to a polymerization reaction with an initiator, ammonium persulfate, and using propylene glycol triglycidyl ether as a post-crosslinking agent and a base as a catalyst to carry out a crosslinking reaction to obtain a highly water-resistant environmentally friendly emulsion for paper-based packaging materials. Since lauryl methacrylate is selected as a monomer, and lauryl methacrylate is a monomer with a hydrophobic long alkyl chain, the structure obtained after polymerization and crosslinking reaction of the monomer has the characteristics of excellent water-resistant performance. In addition, by using lauryl methacrylate and silicone coupling agent KH151 as modifiers in a coordinated manner, the hydrophobic and water-resistant performance of the product structure can be further improved. In addition, the present invention uses propylene glycol triglycidyl ether as a post-crosslinking agent to carry out a crosslinking reaction, which can transform the linear polymer obtained by the polymerization reaction into a tighter network structure, thereby further improving the water barrier performance of the emulsion product. Therefore, the environmentally friendly emulsion prepared by the present invention has excellent water barrier performance. In addition, the present invention uses heptadecanol polyoxyethylene ether monophosphate as an emulsifier, which not only greatly improves the emulsification performance compared to the commonly used composite emulsifiers in the prior art, but also has significantly low toxicity and low irritation, and is suitable for the preparation of coatings for paper-based packaging materials.

[0039] (2) The method for preparing a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials of the present invention has the advantages of good emulsification effect, environmental protection and mild conditions, and can form a tight network structure, greatly improving the water-resistant performance of the emulsion.

[0040] (3) The present invention provides a method for preparing a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials. The solvent medium in the preparation process is water, and no organic solvent is used. The raw materials used are all green and environmentally friendly. The prepared highly water-resistant and environmentally friendly emulsion does not show acute biological toxicity, and has the characteristics of simple preparation method, mild preparation conditions, and suitability for large-scale production.

[0041] (4) The highly water-barrier environmentally friendly emulsion for paper-based packaging materials of the present invention has the characteristic of excellent water-barrier performance, and the obtained environmentally friendly emulsion coating can be used for paper-based packaging materials.

[0042] (5) A highly water-resistant environmentally friendly emulsion for paper-based packaging materials of the present invention, when the emulsion is coated on the substrate paper at a coating amount of 2.83 gsm, the water-resistant property of the coating increases from 89.23 g / m without coating to 1.3 g / m 2 Reduced to 3.26g / m 2 , therefore, the environmentally friendly emulsion has high water-blocking properties.

[0043] (6) The application of the highly water-barrier environmentally friendly emulsion of the present invention to paper-based packaging materials can make the paper-based packaging materials not only have excellent water-barrier properties but also be green and environmentally friendly.

[0044] (7) A paper-based packaging material of the present invention uses a highly water-barrier environmentally friendly emulsion, has the advantages of excellent water-barrier performance and being green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 The invention discloses a synthetic route of a highly water-resistant environmentally friendly emulsion in a method for preparing a highly water-resistant environmentally friendly emulsion for paper-based packaging materials.

[0047] Figure 2 This is a nuclear magnetic resonance hydrogen spectrum of a coating formed by a high water-repellent environmentally friendly emulsion prepared by a method for preparing a high water-repellent environmentally friendly emulsion for paper-based packaging materials in Example 1 of the present invention.

[0048] Figure 3 This is an infrared spectrum of a coating formed by a high water-blocking environmentally friendly emulsion prepared by a method for preparing a high water-blocking environmentally friendly emulsion for paper-based packaging materials in Example 1 of the present invention.

[0049] Figure 4 This is a SEM image of a coating formed on the surface of a paper base by a highly water-resistant environmentally friendly emulsion prepared in accordance with a method for preparing a highly water-resistant environmentally friendly emulsion for paper-based packaging materials in Example 1 of the present invention. Figure 3 Includes four small figures labeled A, B, C, and D.

[0050] Figure 5 This is a storage stability test diagram of a highly water-resistant environmentally friendly emulsion prepared by a method for preparing a highly water-resistant environmentally friendly emulsion for paper-based packaging materials in Example 1 of the present invention. In the figure, emulsion A is the highly water-resistant environmentally friendly emulsion prepared in Example 1, emulsion B is the state of emulsion A after being placed in an oven at 55°C for one week, and emulsion C is the state of emulsion B after being placed in a refrigerator at -10°C for another week.

[0051] Figure 6 This is the test result of the water barrier performance of the high water barrier environmentally friendly emulsion coating prepared by the method for preparing a high water barrier environmentally friendly emulsion for paper-based packaging materials in Example 1 of the present invention. The figure shows the water absorption of the uncoated sample and sample 2.

[0052] Figure 7 It is a graph showing the water barrier performance test results of the emulsion coatings of Example 1 and Comparative Examples 1-3.

[0053] Figure 8 This is a test result of the anti-sticking performance of the high water-blocking environmentally friendly emulsion coating of Example 1.

[0054] Fig. 9 This is the TG-DTG graph of thermal stability analysis of the high water-blocking environmentally friendly emulsion coating of Example 1.

[0055] Fig.10 This is a diagram of zebrafish embryos exposed to the high water-blocking environmentally friendly emulsion of the blank group and Example 1 for 24 hours.

[0056] Fig.11 This is a picture of zebrafish fry exposed to the high water-blocking environmentally friendly emulsion of the blank group and Example 1 for 72 hours. DETAILED DESCRIPTION

[0057] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0058] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. In the present invention, the singular forms "a", "said" and "the" used in the embodiments and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0059] In an embodiment of the present invention, a method for preparing a highly water-resistant environmentally friendly emulsion for paper-based packaging materials comprises the following steps: using isooctyl acrylate, lauryl methacrylate, styrene and methacrylic acid as reaction monomers, silicone coupling agent KH151 as a modifier, and heptadecanol polyoxyethylene ether monophosphate as an emulsifier, heating and emulsifying to obtain a pre-emulsion, then subjecting the pre-emulsion to a polymerization reaction with an initiator, ammonium persulfate, and using propylene glycol triglycidyl ether as a post-crosslinking agent and a base as a catalyst to carry out a crosslinking reaction to obtain the highly water-resistant environmentally friendly emulsion for paper-based packaging materials.

[0060] In the embodiment, a method for preparing a highly water-blocking environmentally friendly emulsion for paper-based packaging materials is described. Since lauryl methacrylate is selected as a monomer, and lauryl methacrylate is a monomer with a long hydrophobic alkyl chain, the structure obtained after polymerization and cross-linking reaction of the monomer has the characteristics of excellent water-blocking performance. In addition, the present invention uses propylene glycol triglycidyl ether as a post-crosslinking agent to carry out a cross-linking reaction, which can transform the linear polymer obtained by the polymerization reaction into a tighter network structure, thereby further improving the water-blocking performance of the emulsion product. In addition, the present invention uses heptadecanol polyoxyethylene ether monophosphate as an emulsifier, which not only greatly improves the emulsifying performance compared to the commonly used composite emulsifiers in the prior art, but also has significantly low toxicity and low irritation, and is suitable for the preparation of coatings for paper-based packaging materials.

[0061] In some embodiments, the mass ratio of isooctyl acrylate, lauryl methacrylate, styrene, methacrylic acid, silicone coupling agent KH151, and heptadecanol polyoxyethylene ether monophosphate is (5-10): (25-30): (18-25): (4-10): (1-2): (1-3); and / or

[0062] The amount of glycerol triglycidyl ether used is 0.3% to 1% of the mass of the pre-emulsion; and / or

[0063] The amount of the catalyst used is 0.2% to 0.6% of the mass of the pre-emulsion.

[0064] In some embodiments, in the cross-linking reaction, the catalyst is one or a combination of two or more of ammonia water, sodium hydroxide or potassium hydroxide; and / or

[0065] After the cross-linking reaction is completed, alkali is added to adjust the pH value of the emulsion to 9-10; the alkali is one or a combination of two or more of ammonia water, sodium hydroxide or potassium hydroxide.

[0066] In some embodiments, the method for preparing a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials comprises the following steps:

[0067] S1, pre-emulsification: adding an aqueous solution of an emulsifier, heptadecanol polyoxyethylene ether monophosphate, into a reactor, heating, adding a mixed solution of methacrylic acid, styrene, isooctyl acrylate, lauryl methacrylate and silicone coupling agent KH151 into the reactor, stirring and emulsifying, to obtain a pre-emulsified solution;

[0068] S2, polymerization reaction: adding part of the pre-emulsion obtained in S1 and part of the initiator ammonium persulfate solution into another reactor, and carrying out polymerization reaction under heating and constant temperature stirring;

[0069] S3, cross-linking reaction: continue to add the remaining pre-emulsion and the initiator ammonium persulfate solution to the reactor of step S2, and when the pre-emulsion remains 20% to 40%, add the post-cross-linking agent glycerol triglycidyl ether and the base to carry out a cross-linking reaction, then keep the temperature and then cool down to obtain an emulsion;

[0070] S4, adjusting the pH value: adding alkali to the emulsion obtained in step S3 to adjust the pH value to 9-10, thereby obtaining the highly water-resistant and environmentally friendly emulsion for paper-based packaging materials.

[0071] Among them, in the polymerization reaction of step S2, the polymerization method adopts the seed emulsion polymerization method, firstly, a polymerization reaction is carried out through part of the pre-emulsion and part of the initiator ammonium persulfate solution to form a latex micelle-like seed, and then the chain length is further increased on the seed through the cross-linking reaction in step S3 to form a network structure. In addition, when the pre-emulsion has 20% to 40% remaining, the post-cross-linking agent propylene triglycidyl ether and the base are added to carry out the cross-linking reaction, so as to be able to cross-link on the basis of the already formed polymer, so as to form a tighter network structure, so as to further improve the water-blocking performance of the product structure.

[0072] In some embodiments, in step S1, the heating temperature is 75°C to 85°C; and the concentration of the aqueous solution of heptadecanol polyoxyethylene ether monophosphate is 0.03 g / mL to 0.08 g / mL.

[0073] In some embodiments, the polymerization reaction temperature is 75° C. to 85° C., and the polymerization reaction time is 20 min to 40 min; and / or

[0074] The temperature of the cross-linking reaction is 75° C. to 85° C., and the time of the cross-linking reaction is 1.5 h to 2 h; and / or

[0075] The concentration of the ammonium persulfate solution is 0.05 g / mL to 0.15 g / mL.

[0076] In some embodiments, the mass of the pre-emulsion added to the polymerization reaction in step S2 accounts for 5% to 10% of the total mass of the pre-emulsion; and / or

[0077] The mass of the ammonium persulfate solution added to the polymerization reaction in step S2 accounts for 5% to 10% of the total mass of the ammonium persulfate solution; and / or

[0078] In the step S3, the heat preservation time is 50 min to 70 min; and the temperature is lowered to 40 to 50°C.

[0079] In an embodiment of the present invention, a highly water-resistant environmentally friendly emulsion for paper-based packaging materials is prepared by the above-mentioned method for preparing a highly water-resistant environmentally friendly emulsion for paper-based packaging materials. The highly water-resistant environmentally friendly emulsion for paper-based packaging materials has the characteristics of excellent water-resistant performance.

[0080] In an embodiment of the present invention, a highly water-resistant environmentally friendly emulsion is used in a paper-based packaging material. The highly water-resistant environmentally friendly emulsion is prepared by the above-mentioned method for preparing a highly water-resistant environmentally friendly emulsion for a paper-based packaging material.

[0081] In an embodiment of the present invention, a paper-based packaging material is prepared by coating the highly water-resistant environmentally friendly emulsion prepared by the above-mentioned method for preparing a highly water-resistant environmentally friendly emulsion for paper-based packaging materials on a substrate paper and drying the emulsion.

[0082] The following describes the invention in conjunction with specific embodiments.

[0083] Example 1

[0084] A method for preparing a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials comprises the following steps:

[0085] S1, pre-emulsification: add an aqueous solution of an emulsifier, polyoxyethylene methacrylate heptadecanol ether monophosphate, to a reactor, heat to 80°C, add a mixed solution of methacrylic acid, styrene, isooctyl acrylate, lauryl methacrylate and silicone coupling agent KH151 to the reactor, stir and emulsify until blue light appears without obvious reflux, and obtain a pre-emulsified solution; in this embodiment, the mass ratio of isooctyl acrylate, lauryl methacrylate, styrene, methacrylic acid, silicone coupling agent KH151 and polyoxyethylene methacrylate heptadecanol ether monophosphate is 8.5:27.44:21.06:6.5:1.25:1.75; in this embodiment, the concentration of the aqueous solution of polyoxyethylene methacrylate heptadecanol ether monophosphate is 0.05 g / mL;

[0086] S2, polymerization reaction: add part of the pre-emulsion obtained in S1 and part of the initiator ammonium persulfate solution into another reactor, and carry out polymerization reaction at 80° C. and constant temperature stirring for 30 minutes;

[0087] S3, cross-linking reaction: continue to add the remaining pre-emulsion and the initiator ammonium persulfate solution to the reactor of step S2, and when the pre-emulsion remains 20% to 40%, add the post-cross-linking agent glycerol triglycidyl ether and the catalyst, carry out cross-linking reaction at 80° C. for 1.8 hours, then keep warm for 60 minutes and then cool to 45° C. to obtain an emulsion; in this embodiment, the amount of glycerol triglycidyl ether is 0.6% of the mass of the pre-emulsion; in this embodiment, the amount of the catalyst is 0.4% of the mass of the pre-emulsion; in this embodiment, the catalyst is ammonia water; in this embodiment, the concentration of the ammonium persulfate solution is 0.10 g / mL;

[0088] S4, adjusting the pH value: adding ammonia water to the emulsion obtained in step S3 to adjust the pH value to 9.5, thereby obtaining a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials.

[0089] In this embodiment, the mass of the pre-emulsion added to the polymerization reaction in step S2 accounts for 10% of the total mass of the pre-emulsion; in this embodiment, the mass of the ammonium persulfate solution added to the polymerization reaction in step S2 accounts for 10% of the total mass of the ammonium persulfate solution.

[0090] Example 2

[0091] A method for preparing a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials comprises the following steps:

[0092] S1, pre-emulsification: add an aqueous solution of an emulsifier, polyoxyethylene ether monophosphate of heptadecanol, to a reactor, heat to 75°C, add a mixed solution of methacrylic acid, styrene, isooctyl acrylate, lauryl methacrylate and silicone coupling agent KH151 to the reactor, stir and emulsify until blue light appears without obvious reflux, and obtain a pre-emulsion; in this embodiment, the mass ratio of isooctyl acrylate, lauryl methacrylate, styrene, methacrylic acid, silicone coupling agent KH151 and polyoxyethylene ether monophosphate of heptadecanol is 5:25:18:4:1:1; in this embodiment, the concentration of the aqueous solution of polyoxyethylene ether monophosphate of heptadecanol is 0.03 g / mL;

[0093] S2, polymerization reaction: add part of the pre-emulsion obtained in S1 and part of the initiator ammonium persulfate solution into another reactor, and carry out polymerization reaction at 75° C. and constant temperature stirring for 40 minutes;

[0094] S3, cross-linking reaction: continue to add the remaining pre-emulsion and the initiator ammonium persulfate solution to the reactor of step S2, and when the pre-emulsion remains 20% to 40%, add the post-cross-linking agent glycerol triglycidyl ether and the catalyst, carry out cross-linking reaction at 75° C. for 2 hours, then keep warm for 70 minutes and then cool to 40° C. to obtain an emulsion; in this embodiment, the amount of glycerol triglycidyl ether is 0.3% of the mass of the pre-emulsion; in this embodiment, the amount of the catalyst is 0.2% of the mass of the pre-emulsion; in this embodiment, the catalyst is sodium hydroxide; in this embodiment, the concentration of the ammonium persulfate solution is 0.05 g / mL;

[0095] S4, adjusting the pH value: adding sodium hydroxide to the emulsion obtained in step S3 to adjust the pH value to 10, thereby obtaining a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials.

[0096] In this embodiment, the mass of the pre-emulsion added to the polymerization reaction in step S2 accounts for 5% of the total mass of the pre-emulsion; in this embodiment, the mass of the ammonium persulfate solution added to the polymerization reaction in step S2 accounts for 5% of the total mass of the ammonium persulfate solution.

[0097] Example 3

[0098] A method for preparing a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials comprises the following steps:

[0099] S1, pre-emulsification: add an aqueous solution of an emulsifier, polyoxyethylene methacrylate heptadecanol ether monophosphate, to a reactor, heat to 85°C, add a mixed solution of methacrylic acid, styrene, isooctyl acrylate, lauryl methacrylate and silicone coupling agent KH151 to the reactor, stir and emulsify until blue light appears without obvious reflux, to obtain a pre-emulsified solution; in this embodiment, the mass ratio of isooctyl acrylate, lauryl methacrylate, styrene, methacrylic acid, silicone coupling agent KH151 and polyoxyethylene methacrylate heptadecanol ether monophosphate is 10:30:25:10:2:3; in this embodiment, the concentration of the aqueous solution of polyoxyethylene methacrylate heptadecanol ether monophosphate is 0.08 g / mL;

[0100] S2, polymerization reaction: add part of the pre-emulsion obtained in S1 and part of the initiator ammonium persulfate solution into another reactor, and carry out polymerization reaction at 85° C. and constant temperature stirring for 20 minutes;

[0101] S3, cross-linking reaction: continue to add the remaining pre-emulsion and the initiator ammonium persulfate solution to the reactor of step S2, and when the pre-emulsion remains 20% to 40%, add the post-cross-linking agent glycerol triglycidyl ether and the catalyst, carry out cross-linking reaction at 85° C. for 1.5 hours, then keep warm for 50 minutes and then cool to 50° C. to obtain an emulsion; in this embodiment, the amount of glycerol triglycidyl ether is 1% of the mass of the pre-emulsion; in this embodiment, the amount of the catalyst is 0.6% of the mass of the pre-emulsion; in this embodiment, the catalyst is potassium hydroxide; in this embodiment, the concentration of the ammonium persulfate solution is 0.15 g / mL;

[0102] S4, adjusting the pH value: adding potassium hydroxide to the emulsion obtained in step S3 to adjust the pH value to 9, thereby obtaining a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials.

[0103] In this embodiment, the mass of the pre-emulsion added to the polymerization reaction in step S2 accounts for 8% of the total mass of the pre-emulsion; in this embodiment, the mass of the ammonium persulfate solution added to the polymerization reaction in step S2 accounts for 8% of the total mass of the ammonium persulfate solution.

[0104] Example 4

[0105] A method for preparing a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials comprises the following steps:

[0106] S1, pre-emulsification: add an aqueous solution of an emulsifier, polyoxyethylene methacrylate heptadecanol ether monophosphate, to a reactor, heat to 78°C, add a mixed solution of methacrylic acid, styrene, isooctyl acrylate, lauryl methacrylate and silicone coupling agent KH151 to the reactor, stir and emulsify until blue light appears without obvious reflux, and obtain a pre-emulsified solution; in this embodiment, the mass ratio of isooctyl acrylate, lauryl methacrylate, styrene, methacrylic acid, silicone coupling agent KH151 and polyoxyethylene methacrylate heptadecanol ether monophosphate is 6:27:20:5:1.5:1.5; in this embodiment, the concentration of the aqueous solution of polyoxyethylene methacrylate heptadecanol ether monophosphate is 0.04 g / mL;

[0107] S2, polymerization reaction: add part of the pre-emulsion obtained in S1 and part of the initiator ammonium persulfate solution into another reactor, and carry out polymerization reaction at 78° C. and constant temperature stirring for 35 minutes;

[0108] S3, cross-linking reaction: continue to add the remaining pre-emulsion and the initiator ammonium persulfate solution to the reactor of step S2, and when the pre-emulsion remains 20% to 40%, add the post-cross-linking agent glycerol triglycidyl ether and the catalyst, carry out cross-linking reaction at 78° C. for 1.9 hours, then keep warm for 65 minutes and then cool to 42° C. to obtain an emulsion; in this embodiment, the amount of glycerol triglycidyl ether is 0.4% of the mass of the pre-emulsion; in this embodiment, the amount of the catalyst is 0.3% of the mass of the pre-emulsion; in this embodiment, the catalyst is a combination of sodium hydroxide and potassium hydroxide; in this embodiment, the concentration of the ammonium persulfate solution is 0.08 g / mL;

[0109] S4, adjusting the pH value: adding a combination of sodium hydroxide and potassium hydroxide to the emulsion obtained in step S3 to adjust the pH value to 9.8, thereby obtaining a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials.

[0110] In this embodiment, the mass of the pre-emulsion added to the polymerization reaction in step S2 accounts for 6% of the total mass of the pre-emulsion; in this embodiment, the mass of the ammonium persulfate solution added to the polymerization reaction in step S2 accounts for 7% of the total mass of the ammonium persulfate solution.

[0111] Example 5

[0112] A method for preparing a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials comprises the following steps:

[0113] S1, pre-emulsification: add an aqueous solution of an emulsifier, polyoxyethylene ether monophosphate of heptadecanol, to a reactor, heat to 82°C, add a mixed solution of methacrylic acid, styrene, isooctyl acrylate, lauryl methacrylate and silicone coupling agent KH151 to the reactor, stir and emulsify until blue light appears without obvious reflux, and obtain a pre-emulsion; in this embodiment, the mass ratio of isooctyl acrylate, lauryl methacrylate, styrene, methacrylic acid, silicone coupling agent KH151 and polyoxyethylene ether monophosphate of heptadecanol is 9:28:23:8:1.7:2.5; in this embodiment, the concentration of the aqueous solution of polyoxyethylene ether monophosphate of heptadecanol is 0.07 g / mL;

[0114] S2, polymerization reaction: add part of the pre-emulsion obtained in S1 and part of the initiator ammonium persulfate solution into another reactor, and carry out polymerization reaction at 82° C. and constant temperature stirring for 35 minutes;

[0115] S3, cross-linking reaction: continue to add the remaining pre-emulsion and the initiator ammonium persulfate solution to the reactor of step S2, and when the pre-emulsion remains 20% to 40%, add the post-cross-linking agent glycerol triglycidyl ether and the catalyst, and carry out a cross-linking reaction at 82° C. for 1.9 hours, then keep warm for 55 minutes and then cool to 48° C. to obtain an emulsion; in this embodiment, the amount of glycerol triglycidyl ether is 0.9% of the mass of the pre-emulsion; in this embodiment, the amount of the catalyst is 0.5% of the mass of the pre-emulsion; in this embodiment, the catalyst is ammonia water; in this embodiment, the concentration of the ammonium persulfate solution is 0.12 g / mL;

[0116] S4, adjusting the pH value: adding ammonia water to the emulsion obtained in step S3 to adjust the pH value to 9.3, thereby obtaining a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials.

[0117] In this embodiment, the mass of the pre-emulsion added to the polymerization reaction in step S2 accounts for 9% of the total mass of the pre-emulsion; in this embodiment, the mass of the ammonium persulfate solution added to the polymerization reaction in step S2 accounts for 8% of the total mass of the ammonium persulfate solution.

[0118] Example 6

[0119] A highly water-resistant environmentally friendly emulsion is used in a paper-based packaging material, wherein the highly water-resistant environmentally friendly emulsion is prepared by any one of the methods for preparing a highly water-resistant environmentally friendly emulsion for a paper-based packaging material in Examples 1 to 5. The coating formed by coating the highly water-resistant environmentally friendly emulsion has excellent water-resistant performance and is green and environmentally friendly.

[0120] Example 7

[0121] A paper-based packaging material, wherein the highly water-resistant environmentally friendly emulsion prepared by any one of the methods for preparing a highly water-resistant environmentally friendly emulsion for paper-based packaging materials in Examples 1 to 5 is coated on a substrate paper and dried to obtain the paper-based packaging material. The highly water-resistant environmentally friendly emulsion is coated on the substrate paper, baked at 110° C. for 1 minute, and then cooled to room temperature to obtain the paper-based packaging material. The paper-based packaging material uses a highly water-resistant environmentally friendly emulsion and has the advantages of excellent water-resistant performance and being green and environmentally friendly.

[0122] Comparative Example 1

[0123] A method for preparing an emulsion for paper-based packaging materials. The difference between this comparative example and Example 1 is that lauryl methacrylate is not added as a polymerization monomer in this comparative example, and the remaining components and preparation method are the same as those in Example 1.

[0124] Comparative Example 2

[0125] A method for preparing an emulsion for paper-based packaging materials. The difference between this comparative example and Example 1 is that in the cross-linking reaction in step S3, no post-cross-linking agent propylene triglycidyl ether is added for cross-linking reaction, and the remaining components and preparation method are the same as those in Example 1.

[0126] Comparative Example 3

[0127] A method for preparing an emulsion for paper-based packaging materials. The difference between this comparative example and Example 1 is that polyoxyethylene octylphenol ether-10 (OP-10) and sodium dodecyl sulfate (SDS) are used as composite emulsifiers to replace the aqueous solution of the emulsifier polyoxyethylene heptadecanol monophosphate in Example 1, and the remaining components and preparation method are the same as those in Example 1.

[0128] Structural morphology characterization

[0129] (I) Structural characterization by H NMR spectroscopy

[0130] The coating formed by coating the high water-blocking environmentally friendly emulsion prepared by the method for preparing a high water-blocking environmentally friendly emulsion for paper-based packaging materials in Example 1 was characterized by nuclear magnetic resonance hydrogen spectrum, such as Figure 2 shown.

[0131] Figure 2 In the figure, the resonance peak with a chemical shift of 12.13ppm corresponds to the hydrogen proton of -OH in methacrylic acid (marked as g in the figure); the resonance peaks with chemical shifts of 7.19ppm and 6.65ppm correspond to the hydrogen protons on the benzene ring in styrene (marked as e and f in the figure respectively); the resonance peak with a chemical shift of 3.51ppm corresponds to the hydrogen proton of -O-CH2- in the side chain of the silicone coupling agent KH151 (marked as i in the figure); the resonance peak with a chemical shift of 3.33ppm corresponds to the hydrogen proton of -CH3 in the side chain of the silicone coupling agent KH151 (marked as h in the figure); the resonance peak with a chemical shift of 1.49ppm corresponds to the hydrogen proton of -CH3 in the side chain of the silicone coupling agent KH151 (marked as h in the figure); The peak corresponds to the hydrogen protons of -COO-CH2- in lauryl methacrylate and isooctyl acrylate (marked as c in the figure); the resonance peak with a chemical shift of 2.50 ppm corresponds to the hydrogen protons of -CH- on the polymer main chain (marked as d in the figure); the resonance peak with a chemical shift of 1.25 ppm corresponds to the hydrogen protons of -CH2- on the polymer main chain (marked as a in the figure); the resonance peak with a chemical shift of 0.88 ppm corresponds to the hydrogen protons of -CH3 on the main chain (marked as b in the figure); in addition, there are no other proton peaks of olefin double bonds at chemical shifts of 5.0 ppm to 6.0 ppm, indicating that the polymerization of each monomer is successful.

[0132] (II) Structural characterization by infrared spectroscopy

[0133] The coating formed by coating the high water-blocking environmentally friendly emulsion prepared by the method for preparing a high water-blocking environmentally friendly emulsion for paper-based packaging materials in Example 1 was characterized by infrared spectroscopy. Figure 3 shown.

[0134] Figure 3 Medium, 2960cm -1 The stretching vibration of -CH3 on the polymer main chain is 2870cm -1 and 1451cm -1 The stretching and bending vibration of -CH2 on the main chain is 1728cm -1 The absorption peaks at 1159cm-1 are the characteristic absorption peaks of C=O after polymerization of acrylate monomers such as lauryl methacrylate, isooctyl acrylate, and methacrylic acid. -1 The absorption peaks of lauryl methacrylate, isooctyl acrylate and COC in the crosslinking agent glycerol triglycidyl ether are at 1603 cm -1 and 702cm -1 The characteristic peak of the benzene ring in styrene is 1068cm -1 The peak at 1640 cm is the asymmetric stretching vibration peak of Si-O in the silicone coupling agent KH151. -1 The characteristic peak at does not appear, indicating that there is no olefin double bond in the prepared high water-resistant environmentally friendly emulsion polymer, and each reaction monomer has been completely polymerized.

[0135] (III) Morphological characterization by scanning electron microscopy

[0136] The coating formed by coating the high water-blocking environmentally friendly emulsion prepared by the method for preparing a high water-blocking environmentally friendly emulsion for paper-based packaging materials in Example 1 on the surface of the paper base was characterized by scanning electron microscopy (SEM). Figure 4 shown.

[0137] Figure 4 In the figure, it can be seen from A that the surface of the coating is flat and smooth without any wrinkles. In addition, it can be seen from B and C that the surface of the coating is covered with beautiful leaf-shaped patterns. In addition, it can be seen from D that after the high water-blocking environmentally friendly emulsion is coated on the paper base, a layer of film, i.e., the coating, is formed on the surface.

[0138] Performance Testing

[0139] (I) Basic parameter detection of emulsion

[0140] The high water-resistant environmentally friendly emulsion prepared by the method for preparing a high water-resistant environmentally friendly emulsion for paper-based packaging materials in Example 1 was tested for basic parameters, including appearance and odor, solid content, pH value and viscosity. The test results of each item are shown in Table 1.

[0141] Table 1 Basic parameters of coating emulsion

[0142]

[0143]

[0144] (II) Storage stability test of emulsion

[0145] The storage stability of the highly water-resistant environmentally friendly emulsion prepared by the method for preparing a highly water-resistant environmentally friendly emulsion for paper-based packaging materials in Example 1 was tested. Figure 5 The highly water-resistant and environmentally friendly emulsion of Example 1 was placed in an oven at 55°C for one week, and then placed in a refrigerator at -10°C for one week.

[0146] Figure 5 Among them, emulsion A is the highly water-resistant environmentally friendly emulsion prepared in Example 1, emulsion B is the state of emulsion A after being placed in an oven at 55°C for one week, and emulsion C is the state of emulsion B after being placed in a refrigerator at -10°C for another week. Figure 5 In the experiment, after the B emulsion and the C emulsion were restored to room temperature, there was no change before and after the emulsion, which indicated that the highly water-blocking and environmentally friendly emulsion prepared by the present invention had good storage stability.

[0147] (III) Water barrier performance test of coating

[0148] (1) Water-blocking performance test of Example 1

[0149] The highly water-resistant environmentally friendly emulsion prepared by the preparation method of a highly water-resistant environmentally friendly emulsion for paper-based packaging materials in Example 1 was used to obtain three coating samples, namely, sample 1, sample 2 and sample 3, by controlling different coating amounts (dry film) gram weights, and an uncoated sample was set up. Then, a Cobb water absorption meter was used to measure the water absorption of the uncoated sample, sample 1, sample 2 and sample 3, respectively, to obtain the surface water absorption value (Cobb) of the coating.

[0150] Among them, the calculation formula of the surface water absorption value (Cobb) of the coating is as follows:

[0151]

[0152] Where, C: water absorption value, g / m 2 ; G1: mass of paper and sample before water absorption, g;

[0153] S: area of ​​paper; G2: mass of paper and sample after absorbing water, g.

[0154] The results of the water absorption of the above samples are shown in Table 2.

[0155] Table 2 Water barrier performance test results of high water barrier environmentally friendly emulsion coating of Example 1

[0156]

[0157]

[0158] It can be seen from the test results in Table 2 that the coating formed by the high water-blocking environmentally friendly emulsion prepared by the method for preparing a high water-blocking environmentally friendly emulsion for paper-based packaging materials of the present invention has a water absorption value of 3 g / m 2 ~4g / m 2 Compared with the water absorption value of similar coated paper products in the prior art, the water absorption value is 10g / m 2 The coating formed by the high water-blocking environmentally friendly emulsion prepared by the present invention has excellent water-blocking performance.

[0159] (2) Comparison of water barrier properties between Example 1 and Comparative Examples 1-3

[0160] The highly water-resistant environmentally friendly emulsion prepared by the preparation method of a highly water-resistant environmentally friendly emulsion for paper-based packaging materials in Example 1 and the emulsions prepared in Comparative Examples 1-3 were used to obtain four coating samples with the same coating amount (dry film) gram weight, wherein Example 1 is sample 2, and Comparative Examples 1-3 are samples 4, 5 and 6, respectively. Then, a Cobb water absorption meter was used to measure the water absorption of the above samples 2, 4, 5 and 6, respectively, to obtain the surface water absorption value (Cobb) of the coating.

[0161] The results of the water absorption of the above samples are shown in Table 3.

[0162] Table 3 Test results of water barrier properties of emulsion coatings of Example 1 and Comparative Examples 1-3

[0163]

[0164] From the test results in Table 3, it can be seen that the water absorption value of sample 2 in Example 1 is only 3.26 g / m 2 However, the water absorption values ​​of the samples of Comparative Examples 1-3 were 10.60 g / m 2 , 15.33g / m 2 , 7.43g / m 2 It can be seen that since sample 4 of comparative example 1 does not select lauryl methacrylate as the polymerization monomer, its water barrier performance is worse than that of the coating sample of the present invention, and the difference is large. Figure 7As shown, the coating of sample 4 has dripping and leakage. However, the present invention is more conducive to obtaining a product with good water-blocking performance because lauryl methacrylate with a long hydrophobic alkyl chain is selected as the polymerization monomer. In addition, sample 5 of comparative example 2 does not use propylene glycol triglycidyl ether as a post-crosslinking agent, resulting in the emulsion structure of sample 5 still being a linear polymer structure, not transformed into a tighter network structure, and dripping and leakage occurs. Please refer to Figure 7 In addition, sample 6 of comparative example 3 uses commonly used composite emulsifiers polyoxyethylene octylphenol ether-10 (OP-10) and sodium dodecyl sulfate (SDS), not only the water barrier performance is worse than that of the coating sample 2 of the present invention, but also OP-10 has a certain irritation, SDS is an anionic surfactant that is toxic to the human body and has irritation and sensitization, while the emulsifier polyoxyethylene ether monophosphate of heptadecanol used in the present invention has significantly low toxicity and low irritation compared with other surfactants, and is suitable for the preparation of coatings for paper-based packaging materials.

[0165] (IV) Anti-stick performance test of coating

[0166] The high water-resistant environmentally friendly emulsion prepared by the method for preparing a high water-resistant environmentally friendly emulsion for paper-based packaging materials in Example 1 was coated at different weights (dry film weights) to obtain three coating samples, namely, sample 1, sample 2, and sample 3. The coating surfaces of the three coating samples were respectively placed face-to-face with the printed substrate and stacked together, and a load (load of 6.3 tons / m 2 ), and then placed at 70℃ for 12h, and the condition of the coating contact surface was observed. The results are shown in Table 4.

[0167] Table 4 Test results of anti-sticking performance of high water-blocking environmentally friendly latex coating of Example 1

[0168]

[0169] (V) Mechanical stability test of emulsion

[0170] A suitable amount of the highly water-resistant environmentally friendly emulsion prepared by the method for preparing a highly water-resistant environmentally friendly emulsion for paper-based packaging materials in Example 1 was taken and stirred at high speed for 1 hour using a stirrer, and then the emulsion before and after stirring were respectively applied to form a coating and the change in water-resistant performance was tested. The water absorption values ​​of the emulsion before and after stirring are shown in Table 5.

[0171] Table 5 Water absorption value of emulsion before and after stirring

[0172]

[0173]

[0174] It can be seen from Table 5 that the water absorption value of the emulsion before stirring is 3.15 g / m 2 The water absorption value after stirring is 3.21g / m 2 The difference between the two is only 0.06g / m 2 , the error caused by the test is not excluded. Therefore, it is explained that the high water-blocking environmentally friendly emulsion prepared by the present invention has the advantage of good mechanical stability.

[0175] (VI) Thermal stability test of coating

[0176] The high water-blocking environmentally friendly emulsion prepared by the method for preparing a high water-blocking environmentally friendly emulsion for paper-based packaging materials in Example 1 was subjected to a thermal stability test using a thermogravimetric analyzer, wherein the TG-DTG graph of the thermal stability test result is as follows: Fig. 9 shown.

[0177] Depend on Fig. 9 It can be seen that the high water-resistant environmentally friendly emulsion coating of the present invention only experienced a relatively obvious weight loss once, indicating that the prepared coating composition is uniform and the synthesis effect is good. The initial decomposition temperature of the coating is about 360.3°C, obtained from the horizontal coordinate of the intersection of the tangent line at the weight loss point. At this time, the coating begins to thermally decompose, and the DTG image shows that the decomposition rate is the fastest when it reaches 390.79°C, and finally it is almost completely decomposed at 440.11°C, indicating that the prepared coating can withstand high temperatures below 360.3°C. Therefore, the high water-resistant environmentally friendly emulsion prepared by the present invention has the advantage of good thermal stability.

[0178] (VII) Biological acute toxicity test of emulsion

[0179] The highly water-resistant environmentally friendly emulsion prepared by the preparation method of a highly water-resistant environmentally friendly emulsion for paper-based packaging materials in Example 1 was subjected to a biological acute toxicity test, with zebrafish embryos and fry incubated for 72 hours as the research objects, respectively, and the highly water-resistant environmentally friendly emulsion prepared in Example 1 was diluted with water, and the dilution concentration of the emulsion was 100 mg / L, and then the zebrafish embryos and fry were placed in the diluted emulsion, and a blank control group was set up for parallel experiments to conduct acute toxicity tests and detect the lethality. In this test, the zebrafish embryos were placed in the emulsion for 24 hours, and the fry were placed in the emulsion for 72 hours. Among them, the test results of biological acute toxicity are shown in Table 6 below.

[0180] Table 6 Biological acute toxicity test results of high water barrier environmentally friendly emulsion of Example 1

[0181]

[0182]

[0183] It can be seen from the biological acute toxicity test results in Table 6 that the mortality rate of zebrafish embryos exposed to the high water-blocking environmentally friendly emulsion at a concentration of 100 mg / L for 24 hours is 0%, and the mortality rate of juveniles exposed to the high water-blocking environmentally friendly emulsion at a concentration of 100 mg / L for 72 hours is 0%, indicating that at this concentration, the high water-blocking environmentally friendly emulsion prepared by the present invention does not show acute toxic effects.

[0184] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials, characterized in that: The method comprises the following steps: using isooctyl acrylate, lauryl methacrylate, styrene and methacrylic acid as reaction monomers, silicone coupling agent KH151 as a modifier, and heptadecanol polyoxyethylene ether monophosphate as an emulsifier, heating and emulsifying to obtain a pre-emulsion, then polymerizing the pre-emulsion with an initiator, ammonium persulfate, and using glycerol triglycidyl ether as a post-crosslinking agent and a base as a catalyst to perform a crosslinking reaction to obtain the highly water-resistant environmentally friendly emulsion for paper-based packaging materials; The mass ratio of isooctyl acrylate, lauryl methacrylate, styrene, methacrylic acid, silicone coupling agent KH151, and heptadecanol polyoxyethylene ether monophosphate is (5-10): (25-30): (18-25): (4-10): (1-2): (1-3).

2. The method for preparing a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials according to claim 1, characterized in that: The amount of glycerol triglycidyl ether used is 0.3% to 1% of the mass of the pre-emulsion; and / or The amount of the catalyst used is 0.2% to 0.6% of the mass of the pre-emulsion.

3. The method for preparing a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials according to claim 1, characterized in that: In the cross-linking reaction, the catalyst is one or a combination of two or more of ammonia water, sodium hydroxide or potassium hydroxide; and / or After the cross-linking reaction is completed, alkali is added to adjust the pH value of the emulsion to 9-10; the alkali is one or a combination of two or more of ammonia water, sodium hydroxide or potassium hydroxide.

4. A high resistance for paper-based packaging material as claimed in claim 1 The method for preparing an aqueous environmentally friendly emulsion is characterized in that: The following steps are involved: S1, pre-emulsification: adding an aqueous solution of an emulsifier, heptadecanol polyoxyethylene ether monophosphate, into a reactor, heating, adding a mixed solution of methacrylic acid, styrene, isooctyl acrylate, lauryl methacrylate and silicone coupling agent KH151 into the reactor, stirring and emulsifying, to obtain a pre-emulsified solution; S2, polymerization reaction: adding part of the pre-emulsion obtained in S1 and part of the initiator ammonium persulfate solution into another reactor, and carrying out polymerization reaction under heating and constant temperature stirring; S3, cross-linking reaction: continue to add the remaining pre-emulsion and the initiator ammonium persulfate solution to the reactor of step S2, and when the pre-emulsion remains 20% to 40%, add the post-cross-linking agent glycerol triglycidyl ether and the base to carry out a cross-linking reaction, then keep the temperature and then cool down to obtain an emulsion; S4, adjusting the pH value: adding alkali to the emulsion obtained in step S3 to adjust the pH value to 9-10, thereby obtaining the highly water-resistant and environmentally friendly emulsion for paper-based packaging materials.

5. The method for preparing a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials according to claim 4, characterized in that: In the step S1, the heating temperature is 75° C. to 85° C.; the concentration of the aqueous solution of heptadecanol polyoxyethylene ether monophosphate is 0.03 g / mL to 0.08 g / mL.

6. The method for preparing a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials according to claim 4, characterized in that: The polymerization reaction temperature is 75° C. to 85° C., and the polymerization reaction time is 20 min to 40 min; and / or The temperature of the cross-linking reaction is 75° C. to 85° C., and the time of the cross-linking reaction is 1.5 h to 2 h; and / or The concentration of the ammonium persulfate solution is 0.05 g / mL to 0.15 g / mL.

7. The method for preparing a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials according to claim 4, characterized in that: The mass of the pre-emulsion added to the polymerization reaction in step S2 accounts for 5% to 10% of the total mass of the pre-emulsion; and / or The mass of the ammonium persulfate solution added to the polymerization reaction in step S2 accounts for 5% to 10% of the total mass of the ammonium persulfate solution; and / or In the step S3, the heat preservation time is 50 min to 70 min; and the temperature is lowered to 40 to 50°C.

8. A highly water-resistant and environmentally friendly emulsion for paper-based packaging materials, characterized in that: The invention is prepared by the method for preparing a highly water-resistant and environmentally friendly emulsion for paper-based packaging materials as described in any one of claims 1 to 7.

9. Application of a highly water-resistant environmentally friendly emulsion in paper-based packaging materials, characterized in that: The highly water-resistant environmentally friendly emulsion is prepared by the method for preparing a highly water-resistant environmentally friendly emulsion for paper-based packaging materials according to any one of claims 1 to 7.

10. A paper-based packaging material, characterized in that: The paper-based packaging material is prepared by coating the highly water-resistant environmentally friendly emulsion prepared by the method for preparing a highly water-resistant environmentally friendly emulsion for paper-based packaging material as described in any one of claims 1 to 7 on a substrate paper and drying it.

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