Vacuum bag film and preparation method

Abstract

This invention relates to the field of vacuum bag film technology and discloses a vacuum bag film comprising the following raw materials: 80-120 parts by weight of nylon 6 resin; 0.5-2 parts by weight of modified graphene; 0.1-0.3 parts by weight of lubricant; and 0.1-0.3 parts by weight of antioxidant. The invention also discloses a method for preparing the above-mentioned vacuum bag film, wherein the raw materials are added to a high-speed mixer according to the specified weight parts, the temperature is controlled at 180-190°C, and the uniformly mixed raw materials are added to a twin-screw extruder for blow molding to obtain a vacuum bag film with a thickness of 30-60 μm. This invention incorporates modified graphene oxide into the nylon 6 resin blend system, causing the amide bonds in the nylon 6 molecules to coordinate with the iron ions in the modified graphene, weakening the ability of the amide bonds to form hydrogen bonds with water, thereby obtaining a vacuum bag film with low water absorption.

Description

Technical Field

[0001] This invention relates to the field of vacuum bag film technology, specifically to a vacuum bag film and its preparation method. Background Technology

[0002] Vacuum bag packaging is a packaging method that removes all the air from the bag and seals it, eliminating the conditions for microorganisms to survive. This achieves the goal of extending the shelf life of goods without adding preservatives and is commonly used for food storage.

[0003] Nylon is commonly used in vacuum bag packaging materials because it has good physical strength and puncture resistance. However, due to the large number of amide groups in the molecular structure of nylon, it can form hydrogen bonds with water molecules, thereby absorbing moisture, which leads to poor dimensional stability, affects its actual performance and thus affects the mechanical properties of nylon materials. Summary of the Invention

[0004] This invention provides a vacuum bag film and its preparation method, which uses modified graphene to modify nylon 6 resin substrate to prepare a vacuum bag film with low water absorption rate.

[0005] A vacuum bag film, the raw materials of which include:

[0006] Nylon 6 resin, 80-120 parts by weight;

[0007] Modified graphene, 0.5-2 parts by weight;

[0008] Lubricant, 0.1-0.3 parts by weight;

[0009] Antioxidant, 0.1-0.3 parts by weight;

[0010] The preparation method of modified graphene is as follows:

[0011] Under the action of a cascade catalyst, 1 molar equivalent of 3,13-dihydrooctaphenylbis-sandwich silsesquioxane and 2 molar equivalents of 4-vinylbenzyl alcohol undergo a hydrosilylation reaction to generate a dihydroxylated octaphenylbis-sandwich silsesquioxane monomer.

[0012] One molar equivalent of dihydroxylated octaphenyl bis-sandwich silsesquioxane monomer and two molar equivalents of p-toluenesulfonyl chloride were subjected to a nucleophilic substitution reaction to generate di-p-methylbenzenesulfonyloxy esterified octaphenyl bis-sandwich silsesquioxane monomer. The di-p-methylbenzenesulfonyloxy esterified octaphenyl bis-sandwich silsesquioxane monomer was then subjected to an azide reaction. Subsequently, under a hydrogen atmosphere and with palladium on carbon as a catalyst, diaminolated octaphenyl bis-sandwich silsesquioxane monomer was prepared.

[0013] Modified graphene was prepared by grafting diamino-octaphenyl bis-sandwich silsesquioxane monomer onto the surface of graphene oxide based on amidation reaction, and by loading iron ions onto the surface of graphene oxide based on coordination.

[0014] Preferably, the lubricant is any one of ethylene bisoleamide, Akama L1000, and pentaerythritol stearate.

[0015] Preferably, the antioxidant is any one of antioxidant 1098, antioxidant 1010 and antioxidant 626.

[0016] Preferably, the thickness of the vacuum bag film is 30-60 μm.

[0017] A method for preparing a vacuum bag film includes the following steps:

[0018] The raw materials are added to a high-speed mixer according to the specified weight proportions and mixed evenly. The temperature is controlled at 180-190℃. The evenly mixed raw materials are then added to a twin-screw extruder for blow molding. The screw speed is 15-25 r / min, the blow-up ratio is 2-3, the temperature of zone 1 is 185-195℃, the temperature of zone 2 is 225-235℃, the temperature of zone 3 is 235-245℃, the runner temperature is 245-255℃, and the die temperature is 240-250℃ to obtain a vacuum bag film.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] This invention: First, 3,13-dihydrooctaphenyl bis-sandwich silsesquioxane and 4-vinylbenzyl alcohol are used as raw materials to obtain dihydroxylated octaphenyl bis-sandwich silsesquioxane monomer through hydrosilylation reaction. Dihydroxylated octaphenyl bis-sandwich silsesquioxane monomer and p-toluenesulfonyl chloride are used as raw materials to generate di-p-methylbenzenesulfonyloxyesterified octaphenyl bis-sandwich silsesquioxane monomer, which is then subjected to azidation reaction. Finally, palladium on carbon is used as a catalyst to reduce the nitrogen group to diaminolated octaphenyl bis-sandwich silsesquioxane monomer. Based on amidation reaction, diaminolated octaphenyl bis-sandwich silsesquioxane monomer is grafted onto the surface of graphene oxide, and based on coordination, iron ions are loaded on the surface of graphene oxide to obtain modified graphene.

[0021] Modified graphene is used to blend and modify nylon resin. On the one hand, modified graphene, as a filler, has good dispersibility in nylon resin, which can avoid agglomeration and effectively improve the stability of modified graphene in nylon resin, improve the mechanical properties of the system, and reduce the water absorption rate of vacuum bag film. On the other hand, the iron ions in modified graphene coordinate with -CONH- in nylon molecules, further enhancing the dispersibility of modified graphene particles in nylon resin, while greatly weakening the ability of -CONH- in nylon molecules to form hydrogen bonds with water, thereby further reducing the water absorption rate of vacuum bag film. Through blow molding process, vacuum bag film with low water absorption rate is obtained. Attached Figure Description

[0022] Figure 1 The experimental results for the water absorption rate of the membrane products prepared in Example 2 and the comparative example are shown.

[0023] Figure 2 The experimental results show the longitudinal tensile strength of the film products prepared in Example 2 and the comparative example. Detailed Implementation

[0024] Experimental Example 1:

[0025] The preparation method of graphene oxide is as follows:

[0026] In an ice bath environment, 110 mL of concentrated sulfuric acid was added to the reaction vessel, cooled to 0°C, 5 g of expanded graphite powder was added, and the mixture was stirred for 45 min. The temperature was raised to 10°C, 25 g of potassium permanganate was added to the reaction vessel, and the mixture was stirred for 3 h. The temperature was raised to 40°C in a water bath, and the mixture was stirred for 50 min. 120 mL of deionized water was added to the reaction vessel, and the mixture was stirred for 10 min. The temperature was raised to 80°C, 200 mL of deionized water was added to the reaction vessel, and the mixture was stirred for 10 min. 50 mL of 30 wt% hydrogen peroxide was added to the reaction vessel, and the mixture was stirred for 20 min. The mixture was allowed to stand for 10 h, filtered, and the filter residue was poured into 200 mL of deionized water. The residue was centrifuged and washed, circulated 3 times, and then freeze-dried to obtain graphene oxide.

[0027] Expanded graphite powder was purchased from Qingdao Tianheda Graphite Co., Ltd., with a particle size of 6.5μm and a grade of Grade 1.

[0028] Experimental Example 2:

[0029] The preparation method of modified graphene is as follows:

[0030] (1) Preparation of 3,13-dihydrooctaphenyl double-sandwich silsesquioxane: The 3,13-dihydrooctaphenyl double-sandwich silsesquioxane was prepared according to the preparation method and steps described in Zhao Bingjie's doctoral dissertation "Morphological structure, shape memory and self-healing properties of organic-inorganic hybrid polymers containing multifaceted oligomeric silsesquioxanes" published by Shanghai Jiao Tong University in 2020.

[0031] (2) Preparation of dihydroxylated octaphenyl bis-sandwich silsesquioxane monomer: The specific experimental steps are as follows: Under nitrogen protection, 18.66 g of 3,13-dihydrooctaphenyl bis-sandwich silsesquioxane, 4.35 g of 4-vinylbenzyl alcohol and 120 mL of toluene were added to a reaction flask and stirred for 0.5 h. 8 drops of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex (Castel catalyst) were added and reacted at 80 °C for 24 h. The mixture was then rotary evaporated to obtain the dihydroxylated octaphenyl bis-sandwich silsesquioxane monomer.

[0032] The caster catalyst was purchased from Hubei Yamaide Biomedical Co., Ltd., CAS number 68478-92-2;

[0033] (3) The specific experimental steps for preparing the diamino-substituted octaphenyl bis-sandwich silsesquioxane monomer are as follows:

[0034] 7.71 g of dihydroxylated octaphenyl bis-clamp silsesquioxane monomer was added to a three-necked flask, 50 mL of toluene was added, the mixture was refluxed for 4 h, rotary evaporated under reduced pressure, cooled to room temperature, 30 mL of pyridine was added, the mixture was stirred for 10 min, and the temperature was lowered to 5 °C.

[0035] Add 2.06 g of p-toluenesulfonyl chloride to 15 mL of dichloromethane and stir until homogeneous to obtain a p-toluenesulfonyl chloride solution. Add the p-toluenesulfonyl chloride solution dropwise to the above three-necked flask, stir and react for 30 h, and then cool to 0 °C.

[0036] Add 40 mL of concentrated hydrochloric acid, 80 mL of deionized water and 100 mL of methanol to a beaker, stir well to obtain a mixed solution;

[0037] The mixed solution was placed into the above three-necked flask and reacted for 30 min. After filtration, the filter cake was washed with 500 mL of deionized water and 100 mL of methanol. It was then placed in a vacuum drying oven at 50 °C and dried for 4 h to obtain di-p-methylbenzenesulfonyl oxyesterified octaphenyl bis-clamp silsesquioxane monomer.

[0038] 3.21 g of di-p-methylbenzenesulfonyl oxyesterified octaphenyl bis-clamp silsesquioxane monomer was placed in a three-necked flask, 30 mL of N,N-dimethylformamide was added, and the mixture was stirred for 0.5 h. Then, 0.24 g of sodium azide was added. Under nitrogen protection, the temperature was raised to 80 °C, and the mixture was stirred for 4 h. 50 mL of deionized water was added, and the mixture was extracted three times with ethyl acetate. The mixture was filtered, concentrated, and the crude product was purified by column chromatography. A mixed solution of petroleum ether and ethyl acetate (petroleum ether: ethyl acetate = 20:1) was used as the eluent. The product was concentrated and placed in a vacuum drying oven at 55 °C for 4 h to obtain the azide product.

[0039] Subsequently, 0.91 g of the azide product was dissolved in 10 mL of methanol, the solution was clarified, 1.13 g of 5% palladium on carbon was added, and the reaction was carried out for 5 h under a hydrogen atmosphere. The mixture was then filtered, concentrated, and placed in a vacuum drying oven at 55 °C for 5 h to obtain the diamino-substituted octaphenyl bis-sandwich silsesquioxane monomer.

[0040] Among them, 5% palladium on carbon was purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd., CAS No. 7440-05-3;

[0041] 30 mg of graphene oxide was added to 30 mL of dimethyl sulfoxide and ultrasonically dispersed for 1 h to obtain a dispersion. 0.3 g of diamino-octaphenyl bis-clamped silsesquioxane monomer was added to the dispersion and reacted at 150 °C for 8 h. After centrifugation, filtration, washing with deionized water 3 times, and freeze-drying at -50 °C for 3 h, graphene oxide grafted with diamino-octaphenyl bis-clamped silsesquioxane monomer was obtained.

[0042] Then, 0.3g of graphene oxide grafted with diamino-octaphenyl bis-sandwich silsesquioxane monomer was placed in 30ml of deionized water, sonicated for 10min, 0.3g of ferric chloride was added, the temperature was raised to 60℃, and the reaction was carried out for 4h. After centrifugation, filtration, washing with deionized water 3 times, and freeze-drying at -50℃ for 3h, modified graphene was obtained.

[0043] Example 1:

[0044] A vacuum bag film, the raw materials of which include:

[0045] Nylon 6 resin, 100 parts by weight;

[0046] Modified graphene, 1 part by weight;

[0047] Lubricant - pentaerythritol stearate, 0.1 parts by weight;

[0048] Antioxidant - Antioxidant 1098, 0.1 parts by weight;

[0049] The nylon 6 resin was purchased from Suzhou Liangda Engineering Plastics Co., Ltd., and its brand name is ST7301.

[0050] Example 2:

[0051] A method for preparing a vacuum bag film is as follows:

[0052] Nylon 6 resin was placed in a vacuum oven and dried at 85°C for 12 hours. The raw materials were then added to a high-speed mixer according to the specified weight ratio, and the temperature was controlled at 190°C for 20 minutes. The uniformly mixed raw materials were then added to a twin-screw extruder for blow molding. The screw speed was 20 r / min, the blow-up ratio was 2.5, the zone 1 temperature was 190°C, the zone 2 temperature was 230°C, the zone 3 temperature was 240°C, the runner temperature was 250°C, and the die temperature was 245°C, resulting in a vacuum bag film with a thickness of 40 μm.

[0053] Comparative Example

[0054] A vacuum bag film, the raw materials of which include:

[0055] Nylon 6 resin, 100 parts by weight;

[0056] Lubricant - pentaerythritol stearate, 0.1 parts by weight;

[0057] Antioxidant - Antioxidant 1098, 0.1 parts by weight;

[0058] The nylon 6 resin was purchased from Suzhou Liangda Engineering Plastics Co., Ltd., and its grade was ST7301.

[0059] A method for preparing a vacuum bag film is as follows:

[0060] Nylon 6 resin was placed in a vacuum oven and dried at 85°C for 12 hours. The raw materials were then added to a high-speed mixer according to the specified weight ratio, and the temperature was controlled at 190°C for 20 minutes. The uniformly mixed raw materials were then added to a twin-screw extruder for blow molding. The screw speed was 15 r / min, the blow-up ratio was 2.5, the zone 1 temperature was 190°C, the zone 2 temperature was 230°C, the zone 3 temperature was 240°C, the runner temperature was 250°C, and the die temperature was 245°C, resulting in a vacuum bag film with a thickness of 40 μm.

[0061] Performance testing

[0062] I. Water Absorption Performance Test

[0063] Cut the membrane product into strips of the same size, place them in an oven, dry them at 120℃ for 2 hours, and record the initial mass m0 of the membrane. Then, immerse the membrane completely in water for 24 hours. After removing the membrane, drain the water and record the mass m1 of the membrane at this time. Calculate the water absorption rate W of the membrane product.

[0064] The formula for calculating water absorption rate is:

[0065] W = [(m1-m0) / m0] × 100%.

[0066] II. Mechanical Property Testing

[0067] The film product was cut into dumbbell-shaped strips with a length of 25mm and a width of 6mm. The longitudinal tensile strength of the film was obtained by using an intelligent electronic tensile testing machine to conduct longitudinal tensile tests on the strips.

[0068] The above experimental results are as follows Figure 1 and 2 As shown.

Claims

1. A vacuum bag film, characterized in that, Including the following raw materials: Nylon 6 resin, 80-120 parts by weight; Modified graphene, 0.5-2 parts by weight; Lubricant, 0.1-0.3 parts by weight; Antioxidant, 0.1-0.3 parts by weight; The preparation method of modified graphene is as follows: Step 1: Under the action of a cascade catalyst, 1 molar equivalent of 3,13-dihydrooctaphenylbis-sandwich silsesquioxane and 2 molar equivalents of 4-vinylbenzyl alcohol are subjected to a hydrosilylation reaction to generate dihydroxylated octaphenylbis-sandwich silsesquioxane monomer. Step 2: Take 1 molar equivalent of dihydroxylated octaphenyl bis-sandwich silsesquioxane monomer and 2 molar equivalents of p-toluenesulfonyl chloride for a nucleophilic substitution reaction to generate di-p-methylbenzenesulfonyloxy esterified octaphenyl bis-sandwich silsesquioxane monomer. Then, subject the di-p-methylbenzenesulfonyloxy esterified octaphenyl bis-sandwich silsesquioxane monomer to an azide reaction. Finally, under a hydrogen atmosphere and with palladium on carbon as a catalyst, prepare diaminolated octaphenyl bis-sandwich silsesquioxane monomer. Modified graphene was prepared by grafting diamino-octaphenyl bis-sandwich silsesquioxane monomer onto the surface of graphene oxide based on amidation reaction, and by loading iron ions onto the surface of graphene oxide based on coordination.

2. The vacuum bag film according to claim 1, characterized in that, The lubricant is any one of ethylene bisoleamide, Akama L1000, and pentaerythritol stearate.

3. The vacuum bag film according to claim 1, characterized in that, The antioxidant is any one of antioxidant 1098, antioxidant 1010 and antioxidant 626.

4. The vacuum bag film according to claim 1, characterized in that, The thickness of the vacuum bag film is 30-60μm.

5. A method for preparing a vacuum bag film as described in any one of claims 1-4, characterized in that, Includes the following steps: The raw materials are added to a high-speed mixer according to the specified weight proportions, and the temperature is controlled at 180-190℃. The uniformly mixed raw materials are then added to a twin-screw extruder for blow molding. The screw speed is 15-25 r / min, the blow-up ratio is 2-3, the temperature of zone 1 is 185-195℃, the temperature of zone 2 is 225-235℃, the temperature of zone 3 is 235-245℃, the runner temperature is 245-255℃, and the die temperature is 240-250℃ to obtain a vacuum bag film.

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