A packaging film easy to be formed by plastic suction and resistant to moist heat sterilization and a preparation method thereof

Abstract

The application provides a packaging film easy to be formed by plastic suction and resistant to moist heat sterilization, which comprises an inner layer, a middle layer and an outer layer; the inner layer is prepared from raw materials comprising the following components: 100 parts by weight of polypropylene resin, 0.08-0.1 parts by weight of ultraviolet light initiator, 0.02-0.1 parts of auxiliary crosslinking agent, 0.05-0.3 parts by weight of lubricant and 0.02-0.2 parts by weight of antioxidant; the middle layer is prepared from raw materials comprising the following components: 100 parts by weight of polypropylene resin, 5-10 parts by weight of multi-arm star-shaped structure styrene thermoplastic elastomer SEBS, 0.06-0.5 parts by weight of lubricant and 0.02-0.4 parts by weight of antioxidant; and the outer layer is prepared from raw materials comprising the following components: 100 parts by weight of nylon resin, 0.02-0.6 parts by weight of lubricant and 0.03-0.5 parts by weight of antioxidant. Compared with the prior art, the packaging film provided by the application is easy to be formed by plastic suction, has low cost, excellent heat resistance and toughness, maintains good dimensional stability during moist heat sterilization and meets the use requirements under moist heat sterilization conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical packaging materials, and more particularly to a packaging film easy to be formed by plastic suction and resistant to moist heat sterilization and a preparation method thereof. BACKGROUND

[0002] In order to meet special sterile requirements, medical device products need to be sterilized. The most commonly used sterilization methods today are ethylene oxide, moist heat sterilization and radiation sterilization. Due to the presence of liquid components in some medical devices, the use of ethylene oxide sterilization will cause ethylene oxide to penetrate the packaging material and dissolve in the liquid component, which cannot be completely volatilized, and there is a safety problem. Radiation sterilization will cause degradation and discoloration of the packaging material, and the packaging material has high requirements for radiation resistance. At the same time, the penetration ability of radiation in a liquid environment is limited, which will lead to insufficient sterilization. Therefore, moist heat sterilization is usually used for medical devices containing liquid components. During moist heat sterilization, the device and the packaging material need to be in a high-temperature and high-pressure steam environment for a long time. For example, the upper film of a pre-filled syringe package uses high-temperature steam paper, and the lower film uses a medical formed film, which requires the formed film to maintain overall dimensional stability during sterilization.

[0003] Therefore, the preferred packaging method for major manufacturers is to use high-temperature steam paper for the upper film to ensure that water vapor can penetrate into the packaging interior for sufficient sterilization, and to use a hard plastic suction box made of polyethylene terephthalate (APET) or other non-crystalline amorphous resin for the lower film to ensure the barrier property, transparency and dimensional stability of the packaging, but this method has a high production cost. In addition, most of the medical formed films sold on the market are made of polypropylene resin (PP) in combination with polypropylene (PP) and polyethylene (PE) or other polyolefin materials by using a multi-layer co-extrusion method. Although the above formed film is soft and hard, it is easy to be formed by plastic suction, but due to the low melting point of the polyolefin material itself, dimensional shrinkage occurs under high-temperature moist heat sterilization conditions. Not only does it affect the appearance of the product packaging, but it may also cause damage to the weak parts of the packaging, resulting in packaging failure and affecting the safety and reliability of the medical device. SUMMARY

[0004] Therefore, the present application aims to provide a packaging film easy to be formed by plastic suction and resistant to moist heat sterilization and a preparation method thereof. The packaging film easy to be formed by plastic suction and resistant to moist heat sterilization provided by the present application is easy to be formed by plastic suction, has a low cost, excellent heat resistance and toughness, maintains good dimensional stability during moist heat sterilization, and meets the use requirements under moist heat sterilization conditions.

[0005] The present application provides a packaging film easy to be formed by plastic suction and resistant to moist heat sterilization, which comprises an inner layer, a middle layer and an outer layer.

[0006] The inner layer is prepared from raw materials comprising the following components:

[0007] 100 parts by weight of polypropylene resin, 0.08-0.1 parts by weight of ultraviolet light initiator, 0.02-0.1 parts of auxiliary crosslinking agent, 0.05-0.3 parts by weight of lubricant, 0.02-0.2 parts by weight of antioxidant;

[0008] The middle layer is prepared from raw materials comprising the following components:

[0009] 100 parts by weight of polypropylene resin, 5-10 parts by weight of multi-arm star structure styrene thermoplastic elastomer SEBS, 0.04-0.5 parts by weight of lubricant, 0.02-0.4 parts by weight of antioxidant;

[0010] The outer layer is prepared from raw materials comprising the following components:

[0011] 100 parts by weight of nylon resin, 0.02-0.6 parts by weight of lubricant, and 0.03-0.5 parts by weight of antioxidant.

[0012] Preferably, in the inner layer, the polypropylene resin is a terpolymer polypropylene, the melt index is 2-8.3 g / min, and the density is 0.74-1.2 g / m 3 ;

[0013] The ultraviolet light initiator is selected from benzophenone and / or benzophenone derivatives;

[0014] The auxiliary crosslinking agent is selected from one or more of triallyl isocyanurate, trimethylolpropane trimethacrylate, and N,N-methylenebisacrylamide;

[0015] The lubricant is selected from one or more of montan wax E wax, oleic acid amide, and erucic acid amide;

[0016] The antioxidant is selected from one or more of antioxidant 1010, antioxidant 168, and antioxidant 1076.

[0017] Preferably, in the middle layer, the polypropylene resin is a homopolymer polypropylene, the melt index is 1.9-7.5 g / min, and the density is 0.86-0.95 g / m 3 .

[0018] Preferably, in the middle layer, the multi-arm star structure styrene thermoplastic elastomer SEBS is a three-arm star structure SEBS and / or a four-arm star structure SEBS; the melt index of the multi-arm star structure styrene thermoplastic elastomer SEBS is 0.1-5 g / 10 min, and the styrene content is 5 wt%-30 wt%.

[0019] Preferably, in the outer layer, the nylon resin is selected from nylon 6 and / or nylon 66; the melt index of the nylon resin is 1.6-3 g / min, and the density is 0.8-3 g / m 3 .

[0020] Preferably, the thickness of the packaging film capable of being formed by plastic absorption and resistant to moist heat sterilization is 90-120 μm, wherein the thickness of the inner layer accounts for 20-25% of the overall film thickness, the thickness of the middle layer accounts for 55-70% of the overall film thickness, and the thickness of the outer layer accounts for 10-20% of the overall film thickness.

[0021] The application also provides a preparation method of the packaging film capable of being formed by plastic absorption and resistant to moist heat sterilization, comprising the following steps:

[0022] a) mixing polypropylene resin, ultraviolet light initiator, crosslinking aid, lubricant and antioxidant, and then sequentially performing first melt blending, extrusion, pelletization, cooling and drying to obtain an inner layer material;

[0023] mixing polypropylene resin, multi-arm star-shaped structure styrene-based thermoplastic elastomer SEBS, lubricant and antioxidant, and then sequentially performing second melt blending, extrusion, pelletization, cooling and drying to obtain a middle layer material;

[0024] mixing nylon resin, lubricant and antioxidant, and then sequentially performing third melt blending, extrusion, pelletization, cooling and drying to obtain an outer layer material;

[0025] b) melting the inner layer material, the middle layer material and the outer layer material respectively by using a multi-layer co-extrusion flow casting method, and then performing flow casting through a die head and cooling to obtain the packaging film capable of being formed by plastic absorption and resistant to moist heat sterilization.

[0026] Preferably, the first melt blending in step a) is performed by using a co-rotating twin-screw extruder, the temperature of the feeding section to the die head of the extruder is 125-200 ℃, the temperature of the die head and the die is 200-210 ℃, and the rotation speed of the main screw is 100-150 r / min;

[0027] the second melt blending is performed by using a co-rotating twin-screw extruder, the temperature of the feeding section to the die head of the extruder is 125-200 ℃, the temperature of the die head and the die is 200-210 ℃, and the rotation speed of the main screw is 100-150 r / min;

[0028] the third melt blending is performed by using a co-rotating twin-screw extruder, the temperature of the feeding section to the die head of the extruder is 150-260 ℃, the temperature of the die head and the die is 220-250 ℃, and the rotation speed of the main screw is 100-150 r / min.

[0029] Preferably, the process of the multi-layer co-extrusion flow casting in step b) is specifically as follows:

[0030] The inner layer material, middle layer material, and outer layer material are melted through the first extruder, the second extruder, and the third extruder, respectively, and then cooled in water at 15℃~18℃ after being cast through a die.

[0031] The temperature from the feeding section to the die of the first extruder is 125-200℃, the temperature of the die head and the die is 200-210℃, and the main screw speed is 100-150 r / min;

[0032] The temperature from the feeding section to the die of the second extruder is 125-200℃, the temperature of the die head and the die is 200-210℃, and the main screw speed is 100-150 r / min;

[0033] The temperature from the feeding section to the die of the second extruder is 150-260°C, the temperature of the die head and the die is 230-240°C, and the main screw speed is 100-150 r / min.

[0034] Preferably, in step b), the easily thermoformable and moisture-heat-resistant packaging film is thermoformed, heat-sealed with a cover film, and then cured and shaped under ultraviolet light to complete the usage process; the thermoforming temperature is 120℃~130℃, and the preheating time is 2s~3s; the heat-sealing temperature is 120℃~140℃, and the time is 2s~4s; the ultraviolet light wavelength for curing and shaping is 280nm~370nm, and the power of the ultraviolet point light source is 8mW / cm². 2 ~10mW / cm 2 .

[0035] This invention provides a packaging film that is easy to thermoform and resistant to moisture heat sterilization, comprising an inner layer, a middle layer, and an outer layer. The inner layer is prepared from raw materials comprising the following components: 100 parts by weight of polypropylene resin, 0.08-0.1 parts by weight of ultraviolet photoinitiator, 0.02-0.1 parts by weight of co-crosslinking agent, 0.05-0.3 parts by weight of lubricant, and 0.02-0.2 parts by weight of antioxidant. The middle layer is prepared from raw materials comprising the following components: 100 parts by weight of polypropylene resin, 5-10 parts by weight of SEBS multi-arm star-shaped styrene thermoplastic elastomer, 0.06-0.5 parts by weight of lubricant, and 0.02-0.4 parts by weight of antioxidant. The outer layer is prepared from raw materials comprising the following components: 100 parts by weight of nylon resin, 0.02-0.6 parts by weight of lubricant, and 0.03-0.5 parts by weight of antioxidant. Compared with the prior art, the packaging film provided by the present invention is easy to blister and resistant to moist heat sterilization. It adopts three layers of specific components with specific content to achieve better overall interaction. The resulting packaging film is easy to blister and resistant to moist heat sterilization, has low cost, excellent heat resistance and toughness, maintains good dimensional stability during moist heat sterilization, and meets the usage requirements under moist heat sterilization conditions.

[0036] In addition, the preparation method provided by the application has simple process, mild conditions, easy operation, easily purchased raw materials, low cost, easy processing, and wide application prospect. DETAILED DESCRIPTION

[0037] The technical solutions of the application will be described clearly and completely below with reference to the embodiments of the application. Obviously, the described embodiments are only some of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0038] The application provides a packaging film easy to be formed by plastic absorption and resistant to moist heat sterilization, comprising an inner layer, a middle layer and an outer layer.

[0039] The inner layer is prepared from raw materials comprising the following components:

[0040] 100 parts by weight of polypropylene resin, 0.08-0.1 parts by weight of ultraviolet light initiator, 0.02-0.1 parts of auxiliary crosslinking agent, 0.05-0.3 parts by weight of lubricant and 0.02-0.2 parts by weight of antioxidant.

[0041] The middle layer is prepared from raw materials comprising the following components:

[0042] 100 parts by weight of polypropylene resin, 5-10 parts by weight of multi-arm star-shaped structure styrene-based thermoplastic elastomer SEBS, 0.06-0.5 parts by weight of lubricant and 0.02-0.4 parts by weight of antioxidant.

[0043] The outer layer is prepared from raw materials comprising the following components:

[0044] 100 parts by weight of nylon resin, 0.02-0.6 parts by weight of lubricant and 0.03-0.5 parts by weight of antioxidant.

[0045] In the application, the packaging film easy to be formed by plastic absorption and resistant to moist heat sterilization comprises an inner layer, a middle layer and an outer layer.

[0046] In the application, the inner layer is prepared from raw materials comprising the following components:

[0047] 100 parts by weight of polypropylene resin, 0.08-0.1 parts by weight of ultraviolet light initiator, 0.02-0.1 parts of auxiliary crosslinking agent, 0.05-0.3 parts by weight of lubricant and 0.02-0.2 parts by weight of antioxidant.

[0048] Preferably prepared from raw materials comprising the following components:

[0049] 100 parts by weight of polypropylene resin, 0.08-0.09 parts by weight of ultraviolet light initiator, 0.02-0.05 parts of crosslinking aid, 0.05-0.1 parts by weight of lubricant, 0.03-0.05 parts by weight of antioxidant.

[0050] In the present application, in the inner layer, the polypropylene resin is preferably terpolymer polypropylene, the melt index is preferably 2-8.3 g / min, and the density is preferably 0.74-1.2 g / m 3 ; the ultraviolet light initiator is preferably selected from benzophenone and / or benzophenone derivatives, more preferably benzophenone; the crosslinking aid is preferably selected from one or more of triallyl isocyanurate, trimethylolpropane trimethacrylate, and N,N-methylenebisacrylamide, more preferably trimethylolpropane trimethacrylate and / or N,N-methylenebisacrylamide; the lubricant is preferably selected from one or more of Montan wax E wax, oleic acid amide, and erucic acid amide, more preferably oleic acid amide; and the antioxidant is preferably selected from one or more of antioxidant 1010, antioxidant 168, and antioxidant 1076, more preferably antioxidant 1010 or antioxidant 168. The present application does not have special restrictions on the sources of the polypropylene resin, ultraviolet light initiator, crosslinking aid, lubricant, and antioxidant, and commercially available products known to those skilled in the art can be used.

[0051] In the present application, the middle layer is prepared from raw materials comprising the following components:

[0052] 100 parts by weight of polypropylene resin, 5-10 parts by weight of multi-arm star-shaped structure styrene-based thermoplastic elastomer SEBS, 0.04-0.5 parts by weight of lubricant, and 0.02-0.4 parts by weight of antioxidant;

[0053] preferably prepared from raw materials comprising the following components:

[0054] 100 parts by weight of polypropylene resin, 8-10 parts by weight of multi-arm star-shaped structure styrene-based thermoplastic elastomer SEBS, 0.05-0.1 parts by weight of lubricant, and 0.03-0.2 parts by weight of antioxidant.

[0055] In the present application, in the middle layer, the polypropylene resin is preferably homopolymer polypropylene, the melt index is preferably 1.9-7.5 g / min, and the density is preferably 0.86-0.95 g / m 3; the multi-arm star-shaped styrenic thermoplastic elastomer SEBS is preferably a three-arm star-shaped SEBS and / or a four-arm star-shaped SEBS; the melt index of the multi-arm star-shaped styrenic thermoplastic elastomer SEBS is preferably 0.1-5 g / 10 min, and the styrene content is preferably 5 wt%-30 wt%; the lubricant is preferably selected from one or more of Montan Wax E wax, oleic acid amide, and erucic acid amide, and is more preferably oleic acid amide; and the antioxidant is preferably selected from one or more of antioxidant 1010, antioxidant 168, and antioxidant 1076, and is more preferably antioxidant 1010 or antioxidant 1076. The source of the polypropylene resin, the multi-arm star-shaped styrenic thermoplastic elastomer SEBS, the lubricant, and the antioxidant is not particularly limited in the present application, and commercially available products known to those skilled in the art can be used.

[0056] In the present application, the outer layer is prepared from raw materials comprising:

[0057] 100 parts by weight of a nylon resin, 0.02-0.6 parts by weight of a lubricant, and 0.03-0.5 parts by weight of an antioxidant;

[0058] and is preferably prepared from raw materials comprising:

[0059] 100 parts by weight of a nylon resin, 0.04-0.06 parts by weight of a lubricant, and 0.03-0.05 parts by weight of an antioxidant.

[0060] In the present application, the nylon resin in the outer layer is preferably selected from nylon 6 and / or nylon 66, and is more preferably nylon 6 or nylon 66; the melt index of the nylon resin is preferably 1.6-3 g / min, and the density is preferably 0.8-3 g / m 3 ; the lubricant is preferably selected from one or more of Montan Wax E wax, oleic acid amide, and erucic acid amide, and is more preferably oleic acid amide or erucic acid amide; and the antioxidant is preferably selected from one or more of antioxidant 1010, antioxidant 168, and antioxidant 1076, and is more preferably antioxidant 1010. The source of the nylon resin, the lubricant, and the antioxidant is not particularly limited in the present application, and commercially available products known to those skilled in the art can be used.

[0061] In the present application, the thickness of the shrinkable and wet-heat sterilization-resistant packaging film is preferably 90-120 µm, and is more preferably 100 µm; wherein the thickness of the inner layer is preferably 20-25% of the overall film thickness, and is more preferably 21-23%; the thickness of the middle layer is preferably 55-70% of the overall film thickness, and is more preferably 62-64%; and the thickness of the outer layer is preferably 10-20% of the overall film thickness, and is more preferably 14-16%.

[0062] The application also provides a preparation method of the packaging film easy to be formed by plastic suction and resistant to moist heat sterilization, comprising the following steps:

[0063] a) mixing the polypropylene resin, the ultraviolet light initiator, the auxiliary crosslinking agent, the lubricant and the antioxidant, and then sequentially performing first melt blending, extrusion, pelletizing, cooling and drying to obtain the inner layer material;

[0064] mixing the polypropylene resin, the multi-arm star-shaped structure styrene thermoplastic elastomer SEBS, the lubricant and the antioxidant, and then sequentially performing second melt blending, extrusion, pelletizing, cooling and drying to obtain the middle layer material;

[0065] mixing the nylon resin, the lubricant and the antioxidant, and then sequentially performing third melt blending, extrusion, pelletizing, cooling and drying to obtain the outer layer material;

[0066] b) melting the inner layer material, the middle layer material and the outer layer material respectively by using a multi-layer co-extrusion flow forming method, and then performing die flow forming and cooling to obtain the packaging film easy to be formed by plastic suction and resistant to moist heat sterilization.

[0067] The application first mixes the polypropylene resin, the ultraviolet light initiator, the auxiliary crosslinking agent, the lubricant and the antioxidant, and then sequentially performs first melt blending, extrusion, pelletizing, cooling and drying to obtain the inner layer material; simultaneously, mixes the polypropylene resin, the multi-arm star-shaped structure styrene thermoplastic elastomer SEBS, the lubricant and the antioxidant, and then sequentially performs second melt blending, extrusion, pelletizing, cooling and drying to obtain the middle layer material; and simultaneously, mixes the nylon resin, the lubricant and the antioxidant, and then sequentially performs third melt blending, extrusion, pelletizing, cooling and drying to obtain the outer layer material.

[0068] In the application, the first melt blending preferably adopts a co-rotating twin-screw extruder, the temperature of the feeding section to the die of the extruder is preferably 125-200 DEG C, the temperature of the head and the die is preferably 200-210 DEG C, and the rotation speed of the main screw is preferably 100-150 r / min, more preferably 120-130 r / min; the second melt blending preferably adopts a co-rotating twin-screw extruder, the temperature of the feeding section to the die of the extruder is preferably 125-200 DEG C, the temperature of the head and the die is preferably 200-210 DEG C, and the rotation speed of the main screw is preferably 100-150 r / min, more preferably 120-130 r / min; and the third melt blending preferably adopts a co-rotating twin-screw extruder, the temperature of the feeding section to the die of the extruder is preferably 150-260 DEG C, the temperature of the head and the die is preferably 220-250 DEG C, and the rotation speed of the main screw is preferably 100-150 r / min, more preferably 120-130 r / min.

[0069] Afterwards, the present application adopts the way of multi-layer co-extrusion casting, melts the above-mentioned inner layer material, middle layer material and outer layer material respectively, and then cools after casting through a die to obtain a packaging film which is easy to be formed by plastic absorption and resistant to moist heat sterilization.

[0070] In the present application, the process of multi-layer co-extrusion casting is preferably specific as follows:

[0071] The inner layer material, the middle layer material and the outer layer material are respectively melted by a first extruder, a second extruder and a third extruder, and then cooled in water at 15-18℃ after casting through a die.

[0072] In the present application, the temperature of the feeding section to the die of the first extruder is preferably 125-200℃, the temperature of the die head and the die is preferably 200-210℃, and the rotation speed of the main screw is preferably 100-150r / min; the temperature of the feeding section to the die of the second extruder is preferably 125-200℃, the temperature of the die head and the die is preferably 200-210℃, and the rotation speed of the main screw is preferably 100-150r / min; the temperature of the feeding section to the die of the second extruder is preferably 150-260℃, the temperature of the die head and the die is preferably 230-240℃, and the rotation speed of the main screw is preferably 100-150r / min.

[0073] In the present application, the packaging film which is easy to be formed by plastic absorption and resistant to moist heat sterilization is subjected to plastic absorption, heat sealing with a cover film, and then ultraviolet light curing and setting to complete the use process.

[0074] In the present application, the temperature of the plastic absorption is preferably 120-130℃, and the preheating time is preferably 2-3s; the temperature of the heat sealing is preferably 120-140℃, and the time is preferably 2-4s; the wavelength of the ultraviolet light for the ultraviolet light curing and setting is preferably 280-370nm, and the power of the ultraviolet point light source is preferably 8-10mW / cm 2 . 2 .

[0075] The commercially available PA\PP and PA\PE formed films cannot withstand the high-temperature environment of moist heat sterilization due to the low melting point of the polyolefin material itself, and there are differences in shrinkage due to the different thermal deformation temperatures and layer thicknesses of the two materials, which can cause poor dimensional stability of the packaging material and the risk of rupture; if the thickness of the outer PA layer is increased, although the shrinkage rate of the packaging material after sterilization is reduced and the dimensional stability of the packaging after sterilization is improved, the difficulty of plastic absorption forming is increased; on the contrary, although the difficulty of plastic absorption forming is reduced, the dimensional stability of the packaging is poor. Therefore, the present application aims to provide a formed film which is easy to be formed by plastic absorption, low in cost, simple in process and meets the moist heat sterilization condition, and solves the problems of dimensional stability and retention after plastic absorption forming.

[0076] In order to overcome the problem that the existing medical forming film cannot meet the moist heat sterilization, the forming film provided by the application adopts three layers, the outer layer is made of nylon (PA), the middle layer is made of polypropylene (PP), and the inner layer is made of polypropylene (PP), and is prepared by adopting a multi-layer co-extrusion process, the middle layer and the inner layer adopt a physical cross-linking and ultraviolet light-induced chemical cross-linking cooperative mode to form physical and chemical cross-linking points in the polyolefin base layer, improve the heat resistance of the whole forming film, maintain the dimensional stability, and reduce the shrinkage of the package.

[0077] In the PP forming film middle layer formula, a multi-arm star structure styrene thermoplastic elastomer SEBS is added, compared with linear structure SEBS, the star core of the multi-arm star structure plays the role of permanent cross-linking point, and the star arm is more easily in the anchoring state; meanwhile, an ultraviolet light initiator is added in the PP forming film inner layer formula, without affecting the heat sealing performance, after the blister forming and heat sealing packaging are completed, ultraviolet light is irradiated, the ultraviolet light initiator induces the chemical cross-linking of the PP molecular chain to form chemical cross-linking points, and the heat resistance of the PP is better maintained.

[0078] In addition, the preparation method provided by the application has simple process, reasonable formula, stable material performance, and is easy to realize industrialized production.

[0079] The application provides a packaging film easy to be blister formed and resistant to moist heat sterilization, which comprises an inner layer, a middle layer and an outer layer; the inner layer is prepared from raw materials comprising the following components: 100 parts by weight of polypropylene resin, 0.08-0.1 parts by weight of ultraviolet light initiator, 0.02-0.1 parts of cross-linking agent, 0.05-0.3 parts by weight of lubricant and 0.02-0.2 parts by weight of antioxidant; the middle layer is prepared from raw materials comprising the following components: 100 parts by weight of polypropylene resin, 5-10 parts by weight of multi-arm star structure styrene thermoplastic elastomer SEBS, 0.06-0.5 parts by weight of lubricant and 0.02-0.4 parts by weight of antioxidant; and the outer layer is prepared from raw materials comprising the following components: 100 parts by weight of nylon resin, 0.02-0.6 parts by weight of lubricant and 0.03-0.5 parts by weight of antioxidant. Compared with the prior art, the packaging film provided by the application is easy to be blister formed and resistant to moist heat sterilization, adopts three layers of specific components with specific contents, realizes good mutual interaction as a whole, and the obtained packaging film is easy to be blister formed, low in cost, excellent in heat resistance and toughness, good in dimensional stability during the moist heat sterilization process, and meets the use requirements under the moist heat sterilization condition.

[0080] In addition, the preparation method provided by the application has simple process, mild conditions, easy operation, easy purchase of raw materials, low cost, easy processing, and wide application prospect.

[0081] In order to further illustrate the present application, the following examples are given in detail. In the following examples of the present application, the reagents used are all analytical pure and commercially available unless otherwise specified; wherein the melt index of the terpolymer polypropylene is 6.5 g / min, the density is 0.91 g / m 3 The melt index of the homopolymer polypropylene is 4.5 g / min, the density is 0.91 g / m 3 The melt index of the three-arm star SEBS is 1 g / 10 min, the styrene content is 27 wt%, the melt index of the four-arm star SEBS is 1.4 g / 10 min, the styrene content is 30 wt%, the melt index of the nylon 6 is 2.1 g / min, the density is 0.9 g / m 3 The melt index of the nylon 66 is 3 g / min, the density is 2.8 g / m 3 .

[0082] Example 1

[0083] The packaging film easy to be formed by plastic absorption and resistant to moist heat sterilization comprises, from inside to outside, an inner layer, a middle layer and an outer layer, and the overall thickness is 100 μm, the thickness of the outer layer is 15 μm, the thickness of the middle layer is 63 μm, and the thickness of the inner layer is 22 μm.

[0084] The inner layer composition comprises 100 parts by weight of terpolymer polypropylene, 0.08 parts by weight of benzophenone, 0.02 parts by weight of trimethylolpropane trimethacrylate, 0.05 parts by weight of oleic acid amide and 0.03 parts by weight of antioxidant 1010; the middle layer composition comprises 100 parts by weight of homopolymer polypropylene, 8 parts by weight of three-arm star SEBS, 0.05 parts by weight of oleic acid amide and 0.03 parts by weight of antioxidant 1010; and the outer layer composition comprises 100 parts by weight of nylon 6, 0.05 parts by weight of oleic acid amide and 0.03 parts by weight of antioxidant 1010.

[0085] Preparation method

[0086] First step: preparation of each layer material

[0087] (1) Preparation of inner layer material: polypropylene resin (terpolymer polypropylene), ultraviolet light initiator (benzophenone), auxiliary crosslinking agent (trimethylolpropane trimethacrylate), lubricant (oleic acid amide) and antioxidant (antioxidant 1010) are added into a high-speed mixer and mixed uniformly; then the mixture is added into a co-rotating twin-screw extruder, the temperature of the feeding section to the die of the extruder is set to 125-200 ℃, the temperature of the head and the die is set to 200-210 ℃, and the rotation speed of the main machine screw is set to 120-130 r / min; the blend is extruded through the die, granulated, cooled, dried and packaged to obtain the inner layer material of the formed film.

[0088] (2) Middle layer material preparation: polypropylene resin (homopolymer polypropylene), multi-arm star-shaped structure styrene thermoplastic elastomer SEBS (three-arm star-shaped SEBS), lubricant (oleic acid amide), antioxidant (antioxidant 1010) are added into a high-speed mixer and mixed uniformly; then the mixture is added into a co-rotating twin-screw extruder, the temperature of the extruder from the feeding section to the die is set to 125-200℃, the temperature of the head and the die is 200-210℃, and the main machine screw speed is 120-130 r / min; the blend is extruded through the die, granulated, cooled, dried, and packaged to obtain the middle layer material of the formed film.

[0089] (3) Outer layer material preparation: nylon resin (nylon 6), lubricant (oleic acid amide), antioxidant (antioxidant 1010) are added into a high-speed mixer and mixed uniformly; then the mixture is added into a co-rotating twin-screw extruder, the temperature of the extruder from the feeding section to the die is set to 150-260℃, the temperature of the head and the die is 230-240℃, and the main machine screw speed is 120-130 r / min; the blend is extruded through the die, granulated, cooled, dried, and packaged to obtain the outer layer material of the formed film.

[0090] Second step: preparation of the packaging film

[0091] The inner, middle, and outer layer materials are respectively melted by extruder 1, extruder 2, and extruder 3 through die casting in 15-18℃ water after being cooled; the temperature of the extruder 1 from the feeding section to the die is 125-200℃, the temperature of the head and the die is 200-210℃, and the main machine screw speed is 120-130 r / min; the temperature of the extruder 2 from the feeding section to the die is 125-200℃, the temperature of the head and the die is 200-210℃, and the main machine screw speed is 120-130 r / min; the temperature of the extruder 3 from the feeding section to the die is 150-260℃, the temperature of the head and the die is 230-240℃, and the main machine screw speed is 120-130 r / min; the overall thickness of the formed film is 100 μm, wherein the thickness of the outer layer is 15 μm, the thickness of the middle layer is 63 μm, and the thickness of the inner layer is 22 μm.

[0092] Third step: packaging and ultraviolet light cross-linking and setting

[0093] The prepared packaging film is subjected to vacuum forming, and then heat sealed with a cover film. Ultraviolet light with a wavelength of 280 nm is used for curing and setting after packaging; the vacuum forming parameters are: temperature 120℃, preheating time 2-3 s; the heat sealing parameters are: temperature 130℃, time 2-4 s; the power of the ultraviolet point light source is 9 mW / cm 2 .

[0094] Example 2

[0095] The packaging film easy to be formed by plastic absorption and resistant to moist heat sterilization comprises, from inside to outside, an inner layer, a middle layer and an outer layer, and has a total thickness of 100 μm, an outer layer thickness of 15 μm, a middle layer thickness of 63 μm and an inner layer thickness of 22 μm.

[0096] The inner layer component comprises 100 parts by weight of terpolymerized polypropylene, 0.08 parts by weight of benzophenone, 0.02 parts by weight of an auxiliary crosslinking agent (trimethylolpropane trimethacrylate and N,N-methylene bisacrylamide at a mass ratio of 1:3), 0.05 parts by weight of oleic acid amide and 0.03 parts by weight of antioxidant 168; the middle layer component comprises 100 parts by weight of homopolymerized polypropylene, 8 parts by weight of multi-arm SEBS (three-arm star-shaped SEBS and four-arm star-shaped SEBS at a mass ratio of 1:4), 0.05 parts by weight of oleic acid amide and 0.03 parts by weight of antioxidant 1010; and the outer layer component comprises 100 parts by weight of nylon 6, 0.05 parts by weight of erucic acid amide and 0.03 parts by weight of antioxidant 1010.

[0097] The preparation method is the same as that in Example 1.

[0098] Example 3

[0099] The packaging film easy to be formed by plastic absorption and resistant to moist heat sterilization comprises, from inside to outside, an inner layer, a middle layer and an outer layer, and has a total thickness of 100 μm, an outer layer thickness of 15 μm, a middle layer thickness of 63 μm and an inner layer thickness of 22 μm.

[0100] The inner layer component comprises 100 parts by weight of terpolymerized polypropylene, 0.08 parts by weight of benzophenone, 0.02 parts by weight of N,N-methylene bisacrylamide, 0.05 parts by weight of oleic acid amide and 0.03 parts by weight of antioxidant 168; the middle layer component comprises 100 parts by weight of homopolymerized polypropylene, 10 parts by weight of four-arm star-shaped SEBS, 0.1 parts by weight of oleic acid amide and 0.2 parts by weight of antioxidant 1076; and the outer layer component comprises 100 parts by weight of nylon 66, 0.05 parts by weight of oleic acid amide and 0.03 parts by weight of antioxidant 1010.

[0101] The preparation method is the same as that in Example 1.

[0102] Comparative Example 1

[0103] Comparative Example 1 is based on Example 1, except that no ultraviolet light initiator and auxiliary crosslinking agent are added in Comparative Example 1.

[0104] Comparative Example 2

[0105] Comparative Example 2 is based on Example 1, except that no multi-arm star-shaped SEBS is added in Comparative Example 2.

[0106] Comparative Example 3

[0107] Comparative Example 3 is based on Example 1, except that no UV initiator, crosslinking co-agent and multi-arm star-shaped SEBS is added in Comparative Example 3; and the overall thickness is 100 pm, the outer layer thickness is 40 pm, the middle layer thickness is 30 pm, and the inner layer thickness is 30 pm.

[0108] The various roll film materials prepared by the same molding process are subjected to 120°C blister molding, then heat-sealed with the cover film at 130°C, and cured and shaped by UV light, with a UV wavelength of 280 nm and a UV point light source power of 9 W / cm 2 Then, the sterilized film is subjected to 20 min of moist heat sterilization at 130°C, and then the performance is tested according to the method specified in the multi-layer co-extrusion retort-resistant film for packaging T / SLBZSH 02-2022, and the results are shown in Table 1.

[0109] Table 1 Performance data table

[0110] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Softness Excellent Good Good Good Good Poor Transparency 92％ 94％ 96％ 94％ 93％ 86％ Peel strength 4.7N 5N 4.5N 5.1N 4.7N 4.9N Degree of shrinkage 3％ 2.5％ 2.7％ 9.5％ 8％ 4％

[0111] As can be seen from Table 1, each example achieves relatively ideal performance. Compared with the comparative examples, it can be seen that the UV initiator, crosslinking co-agent and star-shaped multi-arm SEBS can significantly improve the shrinkage of the molded film under high temperature and moist heat sterilization, and do not affect the smooth and transparent molding area during blister molding. Although the shrinkage of Comparative Example 3 is low, the thickness of the PA layer is increased to maintain a low yield, which results in a loss of softness of the molding area and the smoothness of the molding area.

[0112] The above description of the disclosed embodiments enables one of ordinary skill in the art to make or use the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A packaging film capable of being thermoformed and resistant to moist heat sterilization, comprising an inner layer, a middle layer and an outer layer. The inner layer is prepared from a raw material comprising the following components: 100 parts by weight of polypropylene resin, 0.08-0.1 parts by weight of UV initiator, 0.02-0.1 parts of auxiliary crosslinking agent, 0.05-0.3 parts by weight of lubricant, and 0.02-0.2 parts by weight of antioxidant; The middle layer is prepared from a raw material comprising the following components: 100 parts by weight of polypropylene resin, 5-10 parts by weight of multi-arm star-shaped structure styrene thermoplastic elastomer SEBS, 0.04-0.5 parts by weight of lubricant, and 0.02-0.4 parts by weight of antioxidant; The outer layer is prepared from a raw material comprising the following components: 100 parts by weight of nylon resin, 0.02-0.6 parts by weight of lubricant, and 0.03-0.5 parts by weight of antioxidant; The multi-arm star-shaped structure styrene thermoplastic elastomer SEBS is a three-arm star-shaped structure SEBS and / or a four-arm star-shaped structure SEBS; the melt index of the multi-arm star-shaped structure styrene thermoplastic elastomer SEBS is 0.1-5 g / 10 min, and the styrene content is 5 wt%-30 wt%; The easy-plastic-suction-molding and moist-heat-sterilization-resistant packaging film has a thickness of 90-120 μm, wherein, The thickness of the inner layer accounts for 20-25% of the overall film thickness, the thickness of the middle layer accounts for 55-70% of the overall film thickness, and the thickness of the outer layer accounts for 10-20% of the overall film thickness.

2. The easy-plasticizable and moisture and autoclave resistant packaging film according to claim 1, characterized in that, In the inner layer, the polypropylene resin is a terpolymer polypropylene having a melt index of 2 to 8.3 g / min and a density of 0.74 to 1.2 g / m 3 ; The UV initiator is selected from benzophenone and / or benzophenone derivatives; The auxiliary crosslinking agent is selected from one or more of triallyl isocyanurate, trimethylolpropane trimethacrylate, and N,N-methylenebisacrylamide; The lubricant is selected from one or more of Montan wax E wax, oleic acid amide, and erucic acid amide; The antioxidant is selected from one or more of antioxidant 1010, antioxidant 168, and antioxidant 1076.

3. The easy-plasticizable and moisture and autoclave resistant packaging film according to claim 1, characterized in that, In the middle layer, the polypropylene resin is a homopolymer polypropylene having a melt index of 1.9 to 7.5 g / min and a density of 0.86 to 0.95 g / m 3 .

4. The easy-plasticizable and moisture and autoclave resistant packaging film according to claim 1, characterized in that, In the outer layer, the nylon resin is selected from nylon 6 and / or nylon 66; the melt index of the nylon resin is 1.6 to 3 g / min, and the density is 0.8 to 3 g / m 3 . 5.A method for preparing the packaging film capable of being thermoformed and resistant to moist heat sterilization according to any one of claims 1-4, comprising the following steps: a) mixing polypropylene resin, UV initiator, auxiliary crosslinking agent, lubricant, and antioxidant, and then sequentially performing first melt blending, extrusion, granulation, cooling, and drying to obtain inner layer material; mixing polypropylene resin, multi-arm star-shaped structure styrene thermoplastic elastomer SEBS, lubricant, and antioxidant, and then sequentially performing second melt blending, extrusion, granulation, cooling, and drying to obtain middle layer material; mixing nylon resin, lubricant, and antioxidant, and then sequentially performing third melt blending, extrusion, granulation, cooling, and drying to obtain outer layer material; b) melting the above inner layer material, middle layer material, and outer layer material respectively, and then performing die casting and cooling to obtain the packaging film capable of being thermoformed and resistant to moist heat sterilization.

6. The production method according to claim 5, wherein In step a), the first melt blending is performed using a co-rotating twin-screw extruder, the temperature of the feeding section to the die of the extruder is 125-200℃, the temperature of the head and die is 200-210℃, and the rotation speed of the main screw is 100-150 r / min. The second melt blending adopts a co-rotating twin-screw extruder, the temperature of feeding section to die of the extruder is 125-200 DEG C, the temperature of head and die is 200-210 DEG C, and the rotation speed of main screw is 100-150 r / min; The third melt blending adopts a co-rotating twin-screw extruder, the temperature of feeding section to die of the extruder is 150-260 DEG C, the temperature of head and die is 220-250 DEG C, and the rotation speed of main screw is 100-150 r / min.

7. The preparation method according to claim 5, characterized in that, The process of the multi-layer co-extrusion casting in step b) is specifically as follows: The inner layer material, the middle layer material and the outer layer material are respectively melted by the first extruder, the second extruder and the third extruder, and then are cast through a die and cooled in water at 15-18 DEG C; The temperature of feeding section to die of the first extruder is 125-200 DEG C, the temperature of head and die is 200-210 DEG C, and the rotation speed of main screw is 100-150 r / min; The temperature of feeding section to die of the second extruder is 125-200 DEG C, the temperature of head and die is 200-210 DEG C, and the rotation speed of main screw is 100-150 r / min; The temperature of feeding section to die of the second extruder is 150-260 DEG C, the temperature of head and die is 230-240 DEG C, and the rotation speed of main screw is 100-150 r / min.

8. The preparation method according to claim 5, characterized in that, The blister-moldable and moist-heat sterilization-resistant packaging film in step b) is blister-molded, heat-sealed with a cover film, and then cured and shaped by ultraviolet light to complete the use process; the temperature of the blister molding is 120-130°C, and the preheating time is 2-3 seconds; the temperature of the heat sealing is 120-140°C, and the time is 2-4 seconds; the wavelength of the ultraviolet light for curing and shaping by ultraviolet light is 280-370 nm, and the power of the ultraviolet point light source is 8-10 mW / cm 2 . 2 ​