A kind of moisture-absorbing packaging film and its preparation process

Abstract

The invention relates to the technical field of hygroscopic functional packaging materials, and discloses a hygroscopic packaging film and a preparation process thereof. The hygroscopic packaging film comprises the following raw materials: low-density polyethylene resin LDPE, linear low-density polyethylene resin LLDPE, metallocene linear low-density polyethylene mLLDPE, light stabilizer 783, antioxidant 1076, antioxidant 168 and nano-silicon dioxide-loaded hygroscopic agent; the preparation method of the nano-silicon dioxide-loaded hygroscopic agent is: the phosphorus hydroxyl functional group of the hygroscopic monomer rich in hydrophilic phosphite functional group and the hydroxyl functional group rich in the surface of hydroxylated silicon dioxide nanoparticles undergo a dehydration condensation reaction, and the hygroscopic monomer is loaded on the surface of the nano-silicon dioxide to obtain the hygroscopic packaging film product prepared by the invention has very excellent hygroscopic capacity, and can be used in product packaging with moisture-proof and hygroscopic functional requirements.

Description

Technical Field

[0001] The invention relates to the technical field of hygroscopic functional packaging materials, in particular to a hygroscopic packaging film and a preparation process thereof. Background Art

[0002] Traditional moisture-proof packaging mostly uses desiccant as a hygroscopic agent. The desiccant is used to absorb moisture inside the packaging to achieve the purpose of moisture-proofing. However, this type of packaging has some problems, such as increasing packaging costs and the risk of accidental ingestion. This puts forward new technical requirements for packaging materials that have moisture-proof and hygroscopic functions.

[0003] Polyethylene is a thermoplastic resin obtained by polymerization of ethylene monomers. It has good mechanical properties, chemical stability, processability and economic practicality, and is widely used in the packaging field. Polyethylene has good water vapor barrier properties and is not easy to absorb water molecules, so its hygroscopicity is poor. Therefore, it is necessary to improve the hygroscopicity of polyethylene through modification. Summary of the invention

[0004] The present invention provides a hygroscopic packaging film and a preparation process thereof. The hygroscopic packaging film product has very excellent hygroscopic capacity and can be applied to the packaging of products with moisture-proof and hygroscopic functional requirements.

[0005] A hygroscopic packaging film comprises the following raw materials in parts by weight:

[0006] 30-50 parts of low-density polyethylene resin LDPE;

[0007] 30-50 parts of linear low density polyethylene resin LLDPE;

[0008] 15-30 parts of metallocene linear low density polyethylene mLLDPE;

[0009] 0.1-0.8 parts of light stabilizer 783;

[0010] 0.01-0.05 parts of antioxidant 1076;

[0011] 0.01-0.05 parts of antioxidant 168;

[0012] 2-10 parts of nano-silica supported moisture absorbent;

[0013] The nano-silica supported hygroscopic agent is prepared by loading the hygroscopic monomer rich in hydrophilic phosphite functional groups on the surface of nano-silica through a dehydration condensation reaction between the phosphorus hydroxyl functional groups of the hygroscopic monomer rich in hydrophilic phosphite functional groups and the hydroxyl functional groups rich in the surface of hydroxylated nano-silica.

[0014] Preferably, the synthesis method of the hygroscopic monomer a is: a quaternary ammonium reaction is carried out between the tertiary amine functional group in aminotrimethylenephosphonic acid and the bromine functional group in 1,3-dibromopropane, and the molar ratio of the aminotrimethylenephosphonic acid and 1,3-dibromopropane involved in the reaction is controlled to be (2.01-2.10):1, thereby synthesizing the hygroscopic monomer a.

[0015] Preferably, the synthesis method of the hygroscopic monomer b is: under the catalysis of potassium iodide, the chlorine functional group in the octachloropropyl silsesquioxane structure and the tertiary amine functional group in the aminotrimethylene phosphonic acid undergo a quaternary amination reaction, and the amount ratio of the aminotrimethylene phosphonic acid and the octachloropropyl silsesquioxane participating in the reaction is controlled to be (8.05-8.15):1, thereby synthesizing the hygroscopic monomer b.

[0016] Preferably, the thickness of the hygroscopic packaging film is 50-100 μm.

[0017] Preferably, the moisture absorption rate of the hygroscopic packaging film is 15-20%.

[0018] A preparation process of a hygroscopic packaging film, the preparation process comprising: preparing ingredients according to the formula of the hygroscopic packaging film, adding the formula raw materials into a mixing device to fully mix them evenly, extruding and granulating them through a twin-screw extruder, and subjecting the prepared master batches to an extrusion blow molding process to prepare the hygroscopic packaging film.

[0019] Preferably, the process parameters of the twin-screw extruder extrusion granulation are set as follows: the temperatures of zones 1-6 are 140-160°C, 150-160°C, 165-170°C, 170-180°C, 175-180°C, 180-180°C, and the screw speed is 200-500r / min;

[0020] The parameters of the extrusion blow molding process are set as follows: the temperatures of zones 1-4 are 115-120° C., 145-160° C., 160-165° C., 165-175° C., respectively, and the screw speed is 25-50 r / min.

[0021] Preferably, the hygroscopic packaging film is used to package products that require moisture-proof and moisture-absorbing functions.

[0022] Compared with the prior art, the present invention has the following beneficial technical effects:

[0023] The present invention is based on the quaternization reaction of tertiary amine and halogenated hydrocarbon, and synthesizes a hygroscopic monomer (specifically hygroscopic monomer a or hygroscopic monomer b) rich in hydrophilic functional group phosphite functional group (-H2PO3);

[0024] The hygroscopic monomer is loaded on the surface of the nano-silica by a dehydration condensation reaction between the phosphorus hydroxyl functional group of the hygroscopic monomer and the hydroxyl functional group on the surface of the hydroxylated nano-silica, thereby preparing a nano-silica loaded hygroscopic agent;

[0025] The hygroscopic capacity of polyethylene resin was modified by using nano-silica loaded hygroscopic agent to obtain polyethylene masterbatch with hygroscopic function. The polyethylene masterbatch was subjected to extrusion blow molding process to prepare hygroscopic packaging film, and its moisture absorption rate reached more than 18%, showing very excellent hygroscopic capacity. DETAILED DESCRIPTION

[0026] Polyethylene film has good water vapor barrier properties but poor adsorption capacity for water molecules. For this reason, hydrophilic functional groups are introduced to improve the hygroscopic capacity of polyethylene film. Based on this, a desiccant containing rich hydrophilic functional groups is developed and prepared to improve the hygroscopic properties of polyethylene film.

[0027] Experimental Example 1:

[0028] Synthesis of hygroscopic monomer a: quaternization reaction of the tertiary amine functional group in aminotrimethylenephosphonic acid with the chlorine functional group in 1,3-dibromopropane, and controlling the molar ratio of aminotrimethylenephosphonic acid to 1,3-dibromopropane to be 2.08:1, to obtain hygroscopic monomer a, and the specific synthesis steps are: 15.32g of aminotrimethylenephosphonic acid, 2.5mL of 1,3-dibromopropane, 80mL of deionized water and 20mL of anhydrous ethanol are placed in a three-necked flask, stirring is started, and the reaction is carried out at 70°C for 4h. After the reaction is completed, vacuum filtration is performed, washing is carried out with deionized water, and drying is carried out in a vacuum drying oven at 50°C for 8h to obtain hygroscopic monomer a;

[0029] The chemical structure and nuclear magnetic resonance hydrogen spectrum characterization results of the hygroscopic monomer a are as follows:

[0030] ;

[0031] 1 H NMR (400MHz, DMSO-d6, δ): 2.12~2.17(m, 2H), 3.61-3.63(d, 12H), 4.10-4.13(t, 4H), 8.47(s, 12H).

[0032] Experimental Example 2:

[0033] Synthesis of hygroscopic monomer b: Under the catalysis of potassium iodide, the tertiary amine functional group in aminotrimethylenephosphonic acid and the chlorine functional group of octachloropropylsilsesquioxane undergo quaternization reaction, and the molar ratio of aminotrimethylenephosphonic acid to octachloropropylsilsesquioxane is controlled to be 8.1:1 to synthesize hygroscopic monomer b. The specific synthesis steps are: 5.18g of octachloropropylsilsesquioxane, 12.1g of aminotrimethylenephosphonic acid, 60mg of potassium iodide, 20mL of anhydrous ethanol and 80mL of deionized water are added to a flask, nitrogen is introduced for protection, the reaction is stirred at 80°C for 10h, vacuum filtered, washed with methanol, and dried in a vacuum drying oven at 50°C for 12h to obtain hygroscopic monomer b;

[0034] Among them, octachloropropylsilsesquioxane, purity 98%, was purchased from Zhengzhou Alpha Chemical Co., Ltd.;

[0035] The chemical structure and nuclear magnetic resonance hydrogen spectrum characterization results of the hygroscopic monomer b are as follows:

[0036] ;

[0037] Among them, R is ;

[0038] 1 H NMR (400MHz, DMSO-d6, δ): 2.01-2.07 (m, 16H), 3.25-3.28 (t, 16H), 3.58-3.61 (d, 48H), 4.02-4.04 (t, 16H), 9.10 (s, 48H).

[0039] Experimental Example 3:

[0040] Preparation of nano-silica supported hygroscopic agent a, the specific experimental steps of the preparation method are:

[0041] 5 g of silica with a particle size of 20-50 nm and 30 mL of hydrogen peroxide (30 wt%) were added to a flask, ultrasonically dispersed for 1 h, refluxed at 105 ° C for 2 h, centrifuged at 10000 rpm for 1 h, washed with deionized water, and vacuum dried at 80 ° C for 12 h to obtain hydroxylated silica nanoparticles;

[0042] 2 g of hydroxylated silica nanoparticles and 50 mL of a mixed solvent (anhydrous ethanol / deionized water, V / V, 95:5) were added to a flask and ultrasonically dispersed for 1 h. 10 g of hygroscopic monomer a was added and ultrasonically dispersed for 10 min. The mixture was refluxed at 80 ° C for 3 h, centrifuged at 10,000 rpm for 1 h, washed with anhydrous ethanol, and vacuum dried at 80 ° C for 12 h to obtain nano-silica-loaded hygroscopic agent a.

[0043] Experimental Example 4:

[0044] Nano-silica-loaded hygroscopic agent b was prepared. The preparation method and experimental steps of nano-silica-loaded hygroscopic agent b differed from those of nano-silica-loaded hygroscopic agent a only in that 2 g of hygroscopic monomer b was used to replace 10 g of hygroscopic monomer a. Embodiment 1:

[0045] Hygroscopic packaging film a, comprising the following raw materials in parts by weight:

[0046] 40 parts of low-density polyethylene resin LDPE; low-density polyethylene resin LDPE was purchased from Dongguan Zhimao Plastic Raw Materials Co., Ltd., brand 2426H;

[0047] 40 parts of linear low-density polyethylene resin LLDPE; linear low-density polyethylene resin LLDPE was purchased from Dongguan Meida Plastic Raw Materials Co., Ltd., brand YLF-1802;

[0048] 20 parts of metallocene linear low-density polyethylene mLLDPE; the metallocene linear low-density polyethylene mLLDPE was purchased from Yuyao Hongyang Plastic Chemical Co., Ltd., brand AT6101;

[0049] 6 parts of nano-silica supported hygroscopic agent a;

[0050] 0.5 parts of light stabilizer 783;

[0051] 0.03 parts of antioxidant 1076;

[0052] 0.03 parts of antioxidant 168. Embodiment 2:

[0053] Preparation of hygroscopic packaging film a: According to the formula of hygroscopic packaging film a in Example 1, the ingredients are prepared, the formula raw materials are added into a mixing equipment and mixed thoroughly, and granulated by a twin-screw extruder (the process parameters of the twin-screw extruder are set as: the temperatures in zones 1-6 are 150°C, 160°C, 170°C, 175°C, 180°C, and 185°C, respectively, and the screw speed is 300r / min), and the prepared masterbatch is subjected to an extrusion blow molding process (the parameters of the extrusion blow molding process are set as: the temperatures in zones 1-4 are 120°C, 150°C, 165°C, and 170°C, respectively, and the screw speed is 40r / min) to prepare a hygroscopic packaging film a with a thickness of 80μm. Embodiment three:

[0054] A hygroscopic packaging film b is prepared. The formula and preparation method of the hygroscopic packaging film b differ from those of the hygroscopic packaging film a only in that the nano-silica-loaded hygroscopic agent b is used to replace the nano-silica-loaded hygroscopic agent a. Embodiment 4:

[0055] The performance test of the hygroscopic packaging film is carried out as follows:

[0056] 1. Hygroscopic performance experiment: The hygroscopic packaging film is dried to constant weight and then weighed and placed in a dry weighing bottle. The weighing bottle is then placed on the baffle of a dryer filled with saturated salt water, and the dryer is sealed. After absorbing moisture for 48 hours, the weight of the hygroscopic packaging film is weighed and the moisture absorption rate is calculated (the moisture absorption rate is the ratio of the weight increase of the film in a period of time to the weight of the dry film). The experimental results are shown in Table 1 below;

[0057] Table 1 Experimental results of hygroscopic properties of hygroscopic packaging films

[0058]

[0059] Note: The difference between the comparative example (PE film) and the hygroscopic packaging film a is that it does not contain the nano-silica-loaded hygroscopic agent a;

[0060] The experimental results show that the hygroscopic packaging film prepared by the present invention has achieved a beneficial technical effect of significantly improving the hygroscopic capacity compared with pure PE film;

[0061] Among them, there is no significant difference in the hygroscopic capacity between hygroscopic packaging film a and hygroscopic packaging film b.

[0062] 2. Mechanical properties test: According to GB / T4456-2008 "Polyethylene Blown Film for Packaging", the mechanical properties of the samples were tested, and the test results are shown in Table 2 below;

[0063] Table 2 Experimental results of mechanical properties of hygroscopic packaging films

[0064]

[0065] Note: The difference between the comparative example (PE film) and the hygroscopic packaging film a is that it does not contain the nano-silica-loaded hygroscopic agent a.

Claims

1. A hygroscopic packaging film, characterized in that: The invention comprises the following raw materials in parts by weight: 30-50 parts of low-density polyethylene resin LDPE; 30-50 parts of linear low density polyethylene resin LLDPE; 15-30 parts of metallocene linear low density polyethylene mLLDPE; 0.1-0.8 parts of light stabilizer 783; 0.01-0.05 parts of antioxidant 1076; 0.01-0.05 parts of antioxidant 168; 2-10 parts of nano-silica supported moisture absorbent; The nano-silica-loaded hygroscopic agent is prepared by loading the hygroscopic monomer rich in hydrophilic phosphite functional groups on the surface of nano-silica through a dehydration condensation reaction between the phosphorus hydroxyl functional groups of the hygroscopic monomer rich in hydrophilic phosphite functional groups and the hydroxyl functional groups rich in the surface of hydroxylated nano-silica; The hygroscopic monomer is hygroscopic monomer a, and its chemical structural formula is: ； Alternatively, the hygroscopic monomer is hygroscopic monomer b, and its chemical structural formula is: ； Among them, R is .

2. A hygroscopic packaging film according to claim 1, characterized in that: The synthesis method of the hygroscopic monomer a is as follows: a tertiary amine functional group in aminotrimethylenephosphonic acid and a bromine functional group in 1,3-dibromopropane undergo a quaternization reaction, and the molar ratio of the aminotrimethylenephosphonic acid and 1,3-dibromopropane involved in the reaction is controlled to be (2.01-2.10):1, thereby synthesizing the hygroscopic monomer a.

3. A hygroscopic packaging film according to claim 1, characterized in that: The synthesis method of the hygroscopic monomer b is as follows: under the catalysis of potassium iodide, the chlorine functional group in the structure of octachloropropyl silsesquioxane and the tertiary amine functional group in aminotrimethylene phosphonic acid undergo quaternization reaction, and the amount ratio of the aminotrimethylene phosphonic acid and octachloropropyl silsesquioxane involved in the reaction is controlled to be (8.05-8.15):1, thereby synthesizing the hygroscopic monomer b.

4. A hygroscopic packaging film according to any one of claims 1 to 3, characterized in that: The thickness of the hygroscopic packaging film is 50-100 μm.

5. A hygroscopic packaging film according to any one of claims 1 to 3, characterized in that: The moisture absorption rate of the hygroscopic packaging film is 15-20%.

6. A process for preparing a hygroscopic packaging film according to any one of claims 1 to 3, characterized in that: The preparation process comprises the following steps: preparing ingredients according to the formula of the hygroscopic packaging film, adding the formulated raw materials into a mixing device and mixing them evenly, extruding and granulating the master batches through a twin-screw extruder, and subjecting the obtained master batches to an extrusion blow molding process to prepare the hygroscopic packaging film.

7. The process for preparing a hygroscopic packaging film according to claim 6, characterized in that: The process parameters of the twin-screw extruder extrusion granulation are set as follows: the temperatures of zones 1-6 are 140-160°C, 150-160°C, 165-170°C, 170-180°C, 175-180°C, 180-180°C, and the screw speed is 200-500r / min; The parameters of the extrusion blow molding process are set as follows: the temperatures of zones 1-4 are 115-120° C., 145-160° C., 160-165° C., 165-175° C., respectively, and the screw speed is 25-50 r / min.

8. The use of a hygroscopic packaging film according to any one of claims 1 to 3, characterized in that: The hygroscopic packaging film is used for packaging products that require moisture-proof and moisture-absorbing functions.

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