High-barrier film for packaging high-temperature-resistant poached food

Abstract

The invention provides a high-barrier film for packaging high-temperature-boiling-resistant food, which is characterized by sequentially comprising a polypropylene film, a water-resistant film, a polytrifluorochloroethylene film, an epoxy modified organic silicon resin film, a polyurethane film, a flame retardant and a coupling agent from the surface layer to the inner layer, and the adjacent films are adhered by adopting an adhesive. Glucomannan loses acetyl groups after being subjected to alkali treatment, then intermolecular hydrogen bonds are formed, partial crystals are formed due to the action of the hydrogen bonds, a net-shaped structure is formed by taking the crystals as nodes, the structure is stable, heat resistance is achieved, the gel strength hardly changes along with heating intensity, and the water-resistant film is a water-resistant film. The water boiling resistance and the high temperature resistance of the composite film packaging material are remarkably improved, the whole packaging film has the characteristics of low shrinkage rate and high tensile strength after high-temperature treatment, the problems of deformation and shrinkage after a conventional film material is placed in a high-temperature environment are effectively solved, and the performance of the composite film packaging material is improved.

Description

Technical Field

[0001] The invention relates to the field of food packaging, in particular to a high-barrier film for high-temperature-resistant boiled food packaging. Background Art

[0002] At present, the manufacturing of food packaging materials has begun to enter the field of high-tech industries that attract worldwide attention. In my country, plastic flexible packaging materials for food and their manufacturing technology have also received considerable attention and development;

[0003] From the perspective of packaging, food spoilage includes the following reasons: bacterial growth and reproduction is the first major cause of food spoilage, and the presence of oxygen is a necessary condition for bacterial survival and reproduction; oxidation and deterioration of sugar, protein, fat, vitamins and other ingredients in food is another major cause of food spoilage; the loss of the original flavor of food and the infiltration of external odors into food are also common causes of food spoilage; unstable water holding capacity is also a major cause of food spoilage. The increase or loss of the original water in the food will seriously affect the original flavor of the food;

[0004] However, the existing food packaging films have poor oxygen and moisture barrier properties, low mechanical properties, and poor boiling and high temperature resistance, which seriously affects the quality of food. In addition, the food packaging films currently used are difficult to degrade, causing serious pollution to the environment. Summary of the invention

[0005] 1. Technical issues to be solved

[0006] In view of the shortcomings of the prior art, the present invention provides a high-barrier film for high-temperature boiling-resistant food packaging, which solves the problem that the food packaging film in the prior art has poor oxygen barrier and moisture barrier properties, low mechanical properties, poor boiling resistance and high temperature resistance, thereby seriously affecting the quality of food.

[0007] (II) Technical solution

[0008] To achieve the above objectives, the present invention is implemented by the following technical scheme: a high barrier film for high temperature resistant boiled food packaging, which comprises a polypropylene film, a water-resistant film, a polytrifluorochloroethylene film, an epoxy-modified silicone resin film, a polyurethane film, a flame retardant, and a coupling agent in order from the surface layer to the inner layer, and the adjacent films are bonded by an adhesive, the water-resistant film is made of a water-resistant composition, and the water-resistant composition is made of a polyacrylic acid modified polyvinyl alcohol aqueous solution of 75-93%, glycerol 1%-10%, an alkaline catalyst 1-5%, a hydrophobic agent 5-10%, and glucomannan 6-10% in a mass ratio;

[0009] The polyacrylic acid modified polyvinyl alcohol aqueous solution is prepared by adding a certain mass of polyethylene and distilled water into a reactor, stirring in a water bath at 75-100° C. for 1.5-4 hours to prepare an aqueous solution with a mass fraction of 13-25%; dissolving polyacrylic acid in water at room temperature to prepare an aqueous solution with a mass fraction of 2-6%, and then preparing a solution of polyethylene solution and polyacrylic acid solution in a certain mass ratio;

[0010] The preparation of glucomannan comprises the following steps: taking konjac glucomannan and passing it through a 100-200 mesh sieve, adding distilled water in a ratio of 0.6-1:100, soaking it for 15 hours, heating it at 55-65° C. and stirring it for 15-30 minutes, adding calcium hydroxide solution to adjust the pH of the sol to 7-10, heating it to 75-95° C., keeping the temperature for 5 minutes, standing it for 3 hours, centrifuging it at 4000 r / min for 8 minutes, and putting it into a spray dryer for spray drying to obtain glucomannan.

[0011] Preferably, the preparation steps of the adhesive are: adding vinyl acetate monomer, initiator and dispersion medium into a polymerization reactor at an appropriate temperature and stirring speed, the initiator decomposes to generate free radicals, and initiates the polymerization of vinyl acetate monomer. As the reaction proceeds, the polymer molecular chain continues to grow to form an adhesive, and the reaction temperature is maintained between 70-90°C and the pH value is between 2-6.

[0012] Preferably, the flame retardant is magnesium hydroxide.

[0013] Preferably, the coupling agent is a silane coupling agent, and one or more of KH550, KH560, KH570, KH792, DL602, and DL171 are selected.

[0014] Preferably, the spray drying conditions are: inlet temperature 170-200°C, outlet temperature 60-100°C, and injection volume 10%.

[0015] (III) Beneficial effects

[0016] The present invention provides a high barrier film for packaging high temperature resistant boiled food. It has the following beneficial effects:

[0017] 1. After the alkali treatment, the glucomannan in the present invention loses the acetyl group, and then forms intermolecular hydrogen bonds. Due to the action of hydrogen bonds, partial crystals are formed, and a network structure is formed with the crystals as nodes. The structure is stable and heat-resistant, and the gel strength hardly changes with the heating intensity, so that the boiling resistance and high temperature resistance of the present invention are significantly improved, and the entire packaging film has the characteristics of low shrinkage and high tensile strength after high temperature treatment, which effectively overcomes the problem of deformation and shrinkage of conventional film materials after being placed in a high temperature environment, and improves the performance of composite film packaging materials;

[0018] 2. The present invention adds a certain amount of polyacrylic acid to polyvinyl alcohol to allow the polycarboxylic acid to react with -OH under heating to undergo an esterification reaction, thereby obtaining a modified polyvinyl alcohol film having good water resistance. The mechanical strength and water resistance of the film are further enhanced by adding a hydrophobic agent, an alkaline catalyst and glycerol. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Embodiment 1:

[0021] The embodiment of the present invention provides a high barrier film for high temperature resistant boiled food packaging, which comprises a polypropylene film, a water resistant film, a polytrifluorochloroethylene film, an epoxy modified silicone resin film, a polyurethane film, a flame retardant, and a coupling agent in order from the surface layer to the inner layer, and the adjacent films are bonded by an adhesive, the water resistant film is made of a water resistant composition, and the water resistant composition is made of 75% of a polyacrylic acid modified polyvinyl alcohol aqueous solution, 5% of glycerol, 5% of an alkaline catalyst, 8% of a hydrophobic agent, and 7% of glucomannan in a mass ratio;

[0022] The polyacrylic acid modified polyvinyl alcohol aqueous solution is prepared by adding a certain mass of polyethylene and distilled water into a reactor, stirring in a water bath at 75°C for 1.5 hours, and preparing an aqueous solution with a mass fraction of 13%; dissolving polyacrylic acid in water at room temperature to prepare an aqueous solution with a mass fraction of 2%, and then preparing a solution in which the polyethylene solution and the polyacrylic acid solution are prepared in a certain mass ratio;

[0023] Preparation of glucomannan: Take konjac glucomannan and pass it through a 100-mesh sieve, add distilled water at a ratio of 0.6-1:100 and soak for 15 hours, heat at 55°C and stir for 15 minutes, add calcium hydroxide solution to adjust the sol pH to 7, heat to 75°C, keep warm for 5 minutes, let stand for 3 hours, centrifuge at 4000r / min for 8 minutes, put into a spray dryer for spray drying, and obtain glucomannan.

[0024] The preparation steps of the adhesive are as follows: vinyl acetate monomer, initiator and dispersion medium are added into a polymerization reactor at an appropriate temperature and stirring speed, the initiator decomposes to generate free radicals, which initiate polymerization of vinyl acetate monomer. As the reaction proceeds, the polymer molecular chain continues to grow to form an adhesive, and the reaction temperature is maintained at 70°C and the pH value is 2.

[0025] Magnesium hydroxide is selected as the flame retardant.

[0026] The coupling agent is a silane coupling agent, and one or more of KH550, KH560, KH570, KH792, DL602, and DL171 are selected.

[0027] The spray drying conditions were: inlet temperature 170°C, outlet temperature 60°C, and injection volume 10%.

[0028] Embodiment 2:

[0029] A high-barrier film for high-temperature boiling food packaging, which comprises, from the surface layer to the inner layer, a polypropylene film, a water-resistant film, a polytrifluorochloroethylene film, an epoxy-modified silicone resin film, a polyurethane film, a flame retardant, and a coupling agent, and the adjacent films are bonded with an adhesive, and the water-resistant film is made of a water-resistant composition, which is made of 81% of a polyacrylic acid-modified polyvinyl alcohol aqueous solution, 2% of glycerol, 2% of an alkaline catalyst, 7% of a hydrophobic agent, and 8% of glucomannan in a mass ratio;

[0030] The polyacrylic acid-modified polyvinyl alcohol aqueous solution is prepared by adding a certain mass of polyethylene and distilled water into a reactor, stirring in a water bath at 87°C for 3 hours, and preparing an aqueous solution with a mass fraction of 21%; dissolving polyacrylic acid in water at room temperature to prepare an aqueous solution with a mass fraction of 4%, and then preparing a solution in which the polyethylene solution and the polyacrylic acid solution are prepared in a certain mass ratio;

[0031] Preparation of glucomannan: konjac glucomannan was sieved through a 150-mesh sieve, added with distilled water at a ratio of 0.6-1:100, soaked for 15 hours, heated at 60°C and stirred for 24 minutes, calcium hydroxide solution was added to adjust the sol pH to 9, heated to 85°C, kept warm for 5 minutes, allowed to stand for 3 hours, centrifuged at 4000 r / min for 8 minutes, and placed in a spray dryer for spray drying to obtain glucomannan.

[0032] The preparation steps of the adhesive are as follows: vinyl acetate monomer, initiator and dispersion medium are added into a polymerization reactor at an appropriate temperature and stirring speed, the initiator decomposes to generate free radicals, which initiate polymerization of the vinyl acetate monomer. As the reaction proceeds, the polymer molecular chain continues to grow to form an adhesive, and the reaction temperature is maintained at 80°C and the pH value is 4.

[0033] Magnesium hydroxide is selected as the flame retardant.

[0034] The coupling agent is a silane coupling agent, and one or more of KH550, KH560, KH570, KH792, DL602, and DL171 are selected.

[0035] The spray drying conditions were: inlet temperature 185°C, outlet temperature 80°C, and injection volume 10%.

[0036] Embodiment 3:

[0037] A high-barrier film for high-temperature boiling food packaging, which comprises, from the surface layer to the inner layer, a polypropylene film, a water-resistant film, a polytrifluorochloroethylene film, an epoxy-modified silicone resin film, a polyurethane film, a flame retardant, and a coupling agent, and the adjacent films are bonded with an adhesive, and the water-resistant film is made of a water-resistant composition, which is made of 87% of a polyacrylic acid-modified polyvinyl alcohol aqueous solution, 1% of glycerol, 1% of an alkaline catalyst, 5% of a hydrophobic agent, and 6% of glucomannan in a mass ratio;

[0038] The polyacrylic acid-modified polyvinyl alcohol aqueous solution is prepared by adding a certain mass of polyethylene and distilled water into a reactor, stirring in a water bath at 100° C. for 4 hours, and preparing an aqueous solution with a mass fraction of 25%; dissolving polyacrylic acid in water at room temperature to prepare an aqueous solution with a mass fraction of 6%, and then preparing a solution in which the polyethylene solution and the polyacrylic acid solution are prepared in a certain mass ratio;

[0039] Preparation of glucomannan: konjac glucomannan was sieved through a 200-mesh sieve, added with distilled water at a ratio of 0.6-1:100, soaked for 15 hours, heated at 65°C and stirred for 30 minutes, calcium hydroxide solution was added to adjust the sol pH to 10, heated to 95°C, kept warm for 5 minutes, allowed to stand for 3 hours, centrifuged at 4000 r / min for 8 minutes, and placed in a spray dryer for spray drying to obtain glucomannan.

[0040] The preparation steps of the adhesive are as follows: vinyl acetate monomer, initiator and dispersion medium are added into a polymerization reactor at an appropriate temperature and stirring speed, the initiator decomposes to generate free radicals, which initiate polymerization of the vinyl acetate monomer. As the reaction proceeds, the polymer molecular chain continues to grow to form an adhesive, and the reaction temperature is maintained at 90°C and the pH value is 6.

[0041] Magnesium hydroxide is selected as the flame retardant.

[0042] The coupling agent is a silane coupling agent, and one or more of KH550, KH560, KH570, KH792, DL602, and DL171 are selected.

[0043] The spray drying conditions were: inlet temperature 170-200°C, outlet temperature 60-100°C, and injection volume 10%.

[0044] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. High barrier film for high temperature resistant boiled food packaging, characterized in that: The inner layer includes a polypropylene film, a water-resistant film, a polytrifluorochloroethylene film, an epoxy-modified silicone resin film, a polyurethane film, a flame retardant, and a coupling agent in sequence, and the adjacent films are bonded with an adhesive. The water-resistant film is made of a water-resistant composition, which is made of a polyacrylic acid-modified polyvinyl alcohol aqueous solution of 75-93%, glycerol 1%-10%, an alkaline catalyst 1-5%, a hydrophobic agent 5-10%, and glucomannan 6-10% in a mass ratio; The polyacrylic acid modified polyvinyl alcohol aqueous solution is prepared by adding a certain mass of polyethylene and distilled water into a reactor, stirring in a water bath at 75-100° C. for 1.5-4 hours to prepare an aqueous solution with a mass fraction of 13-25%; dissolving polyacrylic acid in water at room temperature to prepare an aqueous solution with a mass fraction of 2-6%, and then preparing a solution of polyethylene solution and polyacrylic acid solution in a certain mass ratio; The preparation of glucomannan comprises the following steps: taking konjac glucomannan and passing it through a 100-200 mesh sieve, adding distilled water in a ratio of 0.6-1:100, soaking it for 15 hours, heating it at 55-65° C. and stirring it for 15-30 minutes, adding calcium hydroxide solution to adjust the pH of the sol to 7-10, heating it to 75-95° C., keeping the temperature for 5 minutes, standing it for 3 hours, centrifuging it at 4000 r / min for 8 minutes, and putting it into a spray dryer for spray drying to obtain glucomannan.

2. The high barrier film for packaging high temperature resistant boiled food according to claim 1, characterized in that: The preparation steps of the adhesive are as follows: vinyl acetate monomer, initiator and dispersion medium are added into a polymerization reactor at an appropriate temperature and stirring speed, the initiator decomposes to generate free radicals, and the polymerization of the vinyl acetate monomer is initiated. As the reaction proceeds, the polymer molecular chain continues to grow to form an adhesive, and the reaction temperature is maintained between 70-90°C and the pH value is between 2-6.

3. The high barrier film for packaging high temperature resistant boiled food according to claim 1, characterized in that: The flame retardant is magnesium hydroxide.

4. The high barrier film for packaging high temperature resistant boiled food according to claim 1, characterized in that: The coupling agent is a silane coupling agent, and one or more of KH550, KH560, KH570, KH792, DL602, and DL171 are selected.

5. The high barrier film for high temperature resistant boiled food packaging according to claim 1, characterized in that: The spray drying conditions are: inlet temperature 170-200° C., outlet temperature 60-100° C., and injection volume 10%.