Multi-layer co-extrusion blow molding bottle and preparation method and application thereof

Abstract

The invention provides a multi-layer co-extrusion blow molding bottle as well as a preparation method and application thereof. The preparation method comprises the following steps: carrying out multi-layer co-extrusion injection molding blow molding on a polycycloolefin compound and nylon, demolding and carrying out heat treatment to obtain the multi-layer co-extrusion blow-molded bottle, the multi-layer co-extrusion blow molding bottle comprises a water vapor blocking layer and an oxygen blocking layer, the water vapor blocking layer comprises a polycycloolefin compound, the oxygen blocking layer comprises nylon, and the ratio of the thickness of the water vapor blocking layer to the thickness of the oxygen blocking layer is larger than or equal to 4: 1. The multi-layer co-extrusion blow-molded bottle provided by the invention has water vapor barrier property and oxygen barrier property at the same time, and is prepared by adopting a one-step multi-layer co-extrusion injection molding blow molding method, the layers are not separated, and the preparation process is low in energy consumption and high in efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of packaging materials, and in particular relates to a multi-layer co-extrusion blow-molded bottle and a preparation method and application thereof. Background Art

[0002] With the development of the pharmaceutical, cosmetic and food packaging industries, especially the development of biomedicine in the sub-sector, higher requirements are placed on direct product packaging throughout the product shelf life. Compared with traditional glass packaging, cyclic olefin copolymer (COC) materials have outstanding advantages in pharmaceutical, cosmetic and food packaging materials: first, higher strength, not easy to break during production, transportation and application, lighter specific gravity, saving transportation costs; second, excellent processing performance, easy to make and shape at one time, more prominent advantages when packaging with larger capacity, small low-temperature shrinkage, easy to cooperate with pistons, better sealing; third, better compatibility with drugs, no metal ion precipitation, better resistance to protein aggregation and adsorption, no risk of delamination when pH>8. Therefore, more and more research and development institutions and manufacturers have chosen cyclic olefin copolymer (COC) for packaging materials.

[0003] CN106433001A discloses a cycloolefin copolymer modified polyolefin composite water-blocking soft packaging material and its preparation method and application. The cycloolefin copolymer modified polyolefin composite water-blocking soft packaging material includes the following components in percentage by mass: 40% to 55% of cycloolefin copolymer, 35% to 45% of polyethylene, 2% to 15% of modified polypropylene, and 2% to 8% of ethylene-octene copolymer, and the sum of each component is 100%. The blending of cycloolefin copolymer, polyethylene and modified polypropylene in the technical solution can effectively improve the physical properties and water-blocking properties of the prepared soft packaging material, and the use of ethylene-octene copolymer can improve the compatibility of cycloolefin copolymer, polyethylene and modified polypropylene, thereby improving the processing stability of the material. At the same time, the disclosed soft packaging material has excellent tear resistance and is not easy to break.

[0004] Cyclic olefin copolymer (COC) has excellent water vapor barrier properties, but poor gas barrier properties, especially oxygen barrier properties, so it is very challenging to package some oxygen-sensitive drugs and foods.

[0005] Therefore, it is necessary to develop a packaging container that has both water vapor barrier and oxygen barrier properties. Summary of the invention

[0006] In view of the deficiencies in the prior art, the object of the present invention is to provide a multi-layer co-extrusion blow-molded bottle and a preparation method and application thereof, wherein the multi-layer co-extrusion blow-molded bottle has both water vapor barrier properties and oxygen barrier properties, there is no separation between layers, and the preparation process has low energy consumption and high efficiency.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for preparing a multi-layer co-extrusion blow-molded bottle, the method comprising the following steps: subjecting a polycycloolefin compound and nylon to multi-layer co-extrusion injection blow molding, demolding and heat treatment to obtain the multi-layer co-extrusion blow-molded bottle;

[0009] The multi-layer co-extrusion blow-molded bottle comprises a water vapor barrier layer and an oxygen barrier layer, the water vapor barrier layer comprises a polycycloolefin compound, the oxygen barrier layer comprises nylon, and the ratio of the thickness of the water vapor barrier layer to the thickness of the oxygen barrier layer is ≥4:1, for example, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1 or 12:1, etc., and more preferably (4 to 10):1.

[0010] In the present invention, the preparation method selects polycycloolefin compounds as water barrier materials and nylon as oxygen barrier materials, and the obtained multi-layer co-extrusion blow-molded bottle has excellent water vapor barrier and oxygen barrier properties. The preparation method can realize multi-layer co-extrusion injection blow molding through the processing method, suitable materials, and the selection of the thickness ratio of the water vapor barrier layer and the oxygen barrier layer, so that the layer structures are mutually adhered and no interlayer separation occurs, and the preparation energy consumption is low and the efficiency is high.

[0011] In the present invention, no adhesive is required in the preparation process of the multi-layer co-extrusion blow-molded bottle, which can effectively reduce the precipitation of solvents and small molecules, and help improve the safety of the multi-layer co-extrusion blow-molded bottle when used in medicine or food packaging; the multi-layer co-extrusion blow-molded bottle is made of plastic material as a whole, which is easy to recycle. The preparation method can realize multi-layer co-extrusion injection molding and blow molding on the same equipment, thereby realizing the one-step preparation of multi-layer co-extrusion blow-molded bottles. Compared with the current preparation methods of multi-layer packaging containers, such as preparing multi-layer barrier films for welding and sealing bags, preparing multi-layer barrier films and then welding them into packaging bottles, injecting materials of different layer structures into the mold in sequence and then blow molding to obtain multi-layer packaging bottles, etc., it has lower energy consumption and higher efficiency.

[0012] Preferably, the polycycloolefin compound comprises cycloolefin copolymer (COC) and / or cycloolefin polymer (COP).

[0013] Preferably, the cycloolefin copolymer comprises any one or a combination of at least two of the structural compounds represented by Formula I, Formula II or Formula III.

[0014]

[0015] Among them, R 1 and R 2 Each is independently selected from hydrogen or C1-C10 (eg, C2, C3, C4, C5, C6, C7, C8 or C9, etc.) alkyl.

[0016] The "C1-C10 alkyl" mentioned in the present invention refers to an alkyl group having 1 to 10 carbon atoms in the main chain, such as methyl, ethyl or propyl.

[0017] In Formula I, Formula II and Formula III, x / (x+y) is each independently 0.20 to 0.90 (e.g., 0.30, 0.40, 0.50, 0.60, 0.70 or 0.80, etc.), and y / (x+y) is each independently 0.10 to 0.80 (e.g., 0.20, 0.30, 0.40, 0.50, 0.60 or 0.70, etc.).

[0018] Preferably, the weight average molecular weight of the cycloolefin copolymer is 50,000 to 250,000 (eg, 70,000, 90,000, 110,000, 130,000, 150,000, 170,000, 190,000, 210,000 or 230,000, etc.).

[0019] Preferably, the cycloolefin copolymer has a melt index of 6 to 45 g / 10 min (e.g., 10 g / 10 min, 15 g / 10 min, 20 g / 10 min, 25 g / 10 min, 30 g / 10 min, 35 g / 10 min or 40 g / 10 min, etc.) at a temperature of 260° C. and a load of 2.16 kg.

[0020] Preferably, the glass transition temperature (Tg) of the cycloolefin copolymer is 60 to 160°C (eg, 70°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C or 150°C, etc.).

[0021] The cycloolefin copolymer of the present invention can be obtained by those skilled in the art through commercial purchase or synthesis according to the prior art, for example, it can be prepared according to the method disclosed in the document A Tailor-Made Metallocene for the Copolymerization of Ethene with Bulky Cycloalkenes, Angew. Chem. Int. Engl. 1995, 34 (20): 2273-2275.

[0022] Preferably, the cycloolefin polymer includes 690R from Zeon Corporation.

[0023] Preferably, the nylon includes any one of nylon 6, nylon 66, nylon 12 or nylon 612, or a combination of at least two of them, and nylon 612 is more preferably used.

[0024] Preferably, the bottle wall of the multi-layer co-extrusion blow-molded bottle comprises an innermost layer, a middle layer and an outermost layer.

[0025] Preferably, the innermost layer and the outermost layer are each independently a water vapor barrier layer.

[0026] Preferably, the intermediate layer is an oxygen barrier layer.

[0027] Preferably, the thickness of the water vapor barrier layer and the oxygen barrier layer are each independently ≥ 0.01 mm, for example, 0.01 mm, 0.05 mm, 0.10 mm, 0.15 mm, 0.20 mm, 0.25 mm, 0.30 mm, 0.35 mm, 0.40 mm or 0.45 mm, etc.

[0028] In the present invention, the thickness of the water vapor barrier layer and the oxygen barrier layer are preferably independently ≥ 0.01 mm, so that the obtained multi-layer co-extrusion blow-molded bottle has better water vapor barrier performance and oxygen barrier performance.

[0029] Preferably, the co-extrusion injection blow molding is performed using a multi-layer injection blow molding machine.

[0030] Preferably, the multi-layer injection blow molding machine is a Novapax NSB E 650 Multilayer electric multi-layer injection blow molding machine.

[0031] In the present invention, the Novapax NSB E 650 Multilayer electric multilayer injection blow molding machine is used to realize co-extrusion injection molding and blow molding on the same multilayer injection blow molding machine, wherein several extruders respectively supply different molten material flows, which are converged and co-extruded in a compound head, so that multiple layers of materials with different properties are compounded with each other during the extrusion process, so that the product has the excellent properties of several different materials and complements each other in properties. The present invention melt co-extrudes polycycloolefin compounds and oxygen barrier polymers, and the materials are extruded and injection molded in the head. After the bottle embryo is injection molded, it is directly transferred to the blow molding mold on the same machine to perform film blowing, demolding, heat treatment and cooling to obtain a multilayer co-extruded blow-molded bottle of a certain volume. Exemplarily, the volume of the multilayer co-extruded blow-molded bottle is 1 to 5000 mL, or a larger volume.

[0032] The screw processing temperature of the polycycloolefin compound in the multi-layer co-extrusion injection blow molding is 250-265°C, for example, 252°C, 254°C, 256°C, 257°C, 258°C, 259°C, 260°C, 261°C, 262°C, 263°C or 264°C.

[0033] Preferably, the screw processing temperature of nylon in the multi-layer co-extrusion injection blow molding is 256-280°C, for example, 259°C, 262°C, 265°C, 268°C, 271°C, 274°C or 277°C.

[0034] Preferably, the absolute value of the difference between the screw processing temperatures of the polycycloolefin compound and nylon is ≤5°C, for example, 0.5°C, 1°C, 1.5°C, 2°C, 2.5°C, 3°C, 3.5°C, 4°C or 4.5°C.

[0035] Preferably, the temperature of the blow molding mold in the multi-layer co-extrusion injection blow molding is 110-145°C, for example, 115°C, 120°C, 125°C, 130°C, 135°C or 140°C.

[0036] Preferably, the blow molding pressure in the multi-layer co-extrusion injection blow molding is 5 to 14 bar, for example, 6 bar, 7 bar, 8 bar, 9 bar, 10 bar, 11 bar, 12 bar or 13 bar.

[0037] Preferably, the temperature of the heat treatment is 90-120°C, for example, 93°C, 96°C, 99°C, 102°C, 105°C, 108°C, 111°C, 114°C or 117°C.

[0038] Preferably, the heat treatment time is ≥5 min, for example, 5.5 min, 6.0 min, 6.5 min, 7.0 min, 7.5 min, 8.0 min, 8.5 min, 9.0 min or 9.5 min, etc.

[0039] In the present invention, heat treatment after demoulding is performed to help eliminate interlayer stress of the multilayer co-extrusion blow-molded bottle and avoid interlayer separation.

[0040] Preferably, the multi-layer co-extrusion injection blow molding further includes a cooling step.

[0041] In the present invention, the shrinkage stress between layers of different materials is reduced as much as possible by controlling the co-extrusion injection molding, blow molding and heat treatment processes in the multi-layer co-extrusion injection blow molding process; the thickness of the water vapor barrier layer and the thickness of the oxygen barrier layer are controlled to be ≥4:1, and the thickness of the oxygen barrier layer in the middle layer is relatively small, so that the water vapor barrier layers of the innermost and outermost layers can limit the excessive shrinkage of the oxygen barrier layers, and ensure that the layers are not separated even when two polycycloolefin compounds and nylon with different shrinkage ratios are used.

[0042] In a second aspect, the present invention provides a multi-layer co-extrusion blow-molded bottle, wherein the multi-layer co-extrusion blow-molded bottle is prepared by the preparation method described in the first aspect.

[0043] In a third aspect, the present invention provides a use of the multi-layer co-extrusion blow-molded bottle as described in the second aspect in medicine or food packaging.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] In the present invention, the preparation method selects polycycloolefin compounds as water-blocking materials and nylon as oxygen-blocking materials, and the obtained multilayer co-extrusion blow-molded bottle has excellent water vapor barrier and oxygen barrier properties; through the processing method, suitable materials, and the selection of the thickness ratio of the water vapor barrier layer and the oxygen barrier layer, the layer structures are made to adhere to each other without interlayer separation, and the preparation has low energy consumption and high efficiency. The obtained multilayer co-extrusion blow-molded bottle does not produce interlayer separation during storage and shelf life. Taking a plastic bottle with a volume of 5mL as an example, under the test conditions of 38°C and 90%RH, the water vapor permeability of the multilayer co-extrusion blow-molded bottle is ≤0.00032g / (pkg·24h); under the test conditions of 23°C and 50%RH, the oxygen permeability is ≤0.0031cm 3 / (pkg·24h·atm). BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A schematic diagram of the cross-sectional structure of a multi-layer co-extrusion blow-molded bottle provided in Example 1;

[0047] Among them, 1-innermost layer; 2-middle layer; 3-outermost layer. DETAILED DESCRIPTION

[0048] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0049] The sources of some components in the following examples and comparative examples are as follows:

[0050] Cycloolefin copolymer: prepared according to the method disclosed in the document A Tailor-Made Metallocene for the Copolymerization of Ethene with Bulky Cycloalkenes, Angew. Chem. Int. Engl. 1995, 34 (20): 2273-2275. The weight average molecular weight is 123,000, the glass transition temperature is 145° C., and the melt index is 12.5 g / 10 min (260° C., 2.16 kg);

[0051] Cycloolefin polymer: brand 690R, manufacturer Zeon, melt index 20g / 10min (280℃, 2.16kg);

[0052] Nylon 6: Brand name FG7301, manufacturer is Celanese;

[0053] Nylon 612: Brand name is Zytel 151NC 010, manufacturer is Celanese;

[0054] Polybutylene terephthalate, brand name CR-8828, manufacturer is China Resources Chemical Materials.

[0055] Example 1

[0056] The present embodiment provides a multi-layer co-extrusion blow-molded bottle and a preparation method thereof, wherein the bottle wall of the multi-layer co-extrusion blow-molded bottle comprises an innermost layer 1, a middle layer 2 and an outermost layer 3 which are stacked in sequence, the innermost layer 1 and the outermost layer 3 are both water vapor barrier layers, and the middle layer 2 is an oxygen barrier layer; the material of the outermost water vapor barrier layer is cycloolefin copolymer, the material of the innermost water vapor barrier layer is cycloolefin copolymer, the material of the oxygen barrier layer is nylon 6, the thickness of the innermost layer is 0.40 mm, the thickness of the middle layer is 0.05 mm, and the thickness of the outermost layer is 0.45 mm.

[0057] The preparation method comprises the following steps: adding cycloolefin copolymer and nylon 6 into three barrels of a Novapax NSB E650 Multilayer electric multilayer injection blow molding machine, performing multilayer co-extrusion injection blow molding on the Novapax NSB E 650 Multilayer electric multilayer injection blow molding machine, wherein the screw processing temperature of the cycloolefin copolymer is 260°C, and the screw processing temperature of nylon 6 is 265°C. After injection molding, the injection-molded preform is directly transferred to a blow molding mold, wherein the blow molding mold temperature is 120°C, the blow molding pressure is 9 bar, blow molding is performed, demolding is performed, and then a heat treatment is performed at 105°C for 5 minutes at a transmission channel to eliminate interlayer stress, and the multilayer co-extrusion blow molding bottle with a volume of 5 mL is obtained after cooling to 25°C at room temperature.

[0058] Example 2

[0059] The present embodiment provides a multi-layer co-extrusion blow-molded bottle and a preparation method thereof. The only difference between the present embodiment and the embodiment 1 is that the material of the innermost water vapor barrier layer is cycloolefin polymer (690R). In the preparation method, cycloolefin copolymer, cycloolefin polymer and nylon 6 are added to three barrels of a Novapax NSB E 650 Multilayer electric multi-layer injection blow molding machine, and multi-layer co-extrusion injection blow molding is carried out on the Novapax NSB E 650 Multilayer electric multi-layer injection blow molding machine. The screw processing temperature of the cycloolefin polymer is 265°C, and other conditions are the same as those in the embodiment 1.

[0060] Example 3

[0061] The present embodiment provides a multi-layer co-extrusion blow-molded bottle and a preparation method thereof. The only difference between the present embodiment and the first embodiment is that the material of the outermost water vapor barrier layer is cycloolefin polymer (690R), and the material of the innermost water vapor barrier layer is cycloolefin polymer (690R). In the preparation method, cycloolefin polymer and nylon 6 are added to three barrels of a Novapax NSB E650 Multilayer electric multi-layer injection blow molding machine, and multi-layer co-extrusion injection blow molding is carried out on the Novapax NSB E 650 Multilayer electric multi-layer injection blow molding machine. The screw processing temperature of the cycloolefin polymer is 265°C, and other conditions are the same as those in the first embodiment.

[0062] Example 4

[0063] The present embodiment provides a multi-layer co-extrusion blow-molded bottle and a preparation method thereof. The only difference between the present embodiment and the embodiment 1 is that the material of the outermost water vapor barrier layer is cycloolefin polymer (690R). In the preparation method, cycloolefin polymer, cycloolefin copolymer and nylon 6 are added to three barrels of a Novapax NSB E 650 Multilayer electric multi-layer injection blow molding machine, and multi-layer co-extrusion injection blow molding is carried out on the Novapax NSB E 650 Multilayer electric multi-layer injection blow molding machine. The screw processing temperature of the cycloolefin polymer is 265°C, and other conditions are the same as those in the embodiment 1.

[0064] Example 5

[0065] This embodiment provides a multi-layer co-extrusion blow-molded bottle and a preparation method thereof, which differs from Embodiment 1 only in that the thickness of the innermost layer is adjusted to 0.40 mm, the thickness of the middle layer is adjusted to 0.08 mm, and the thickness of the outermost layer is adjusted to 0.60 mm, and other conditions are the same as those in Embodiment 1.

[0066] Example 6

[0067] This embodiment 1 provides a multi-layer co-extrusion blow-molded bottle and a preparation method thereof. The only difference between this embodiment and embodiment 1 is that nylon 6 is replaced by nylon 612, and other conditions are the same as those of embodiment 1.

[0068] Comparative Example 1

[0069] This comparative example provides a multi-layer co-extrusion blow-molded bottle and a preparation method thereof, which differs from Example 1 only in that the thickness of the innermost layer is adjusted to 0.40 mm, the thickness of the middle layer is adjusted to 0.25 mm, and the thickness of the outermost layer is adjusted to 0.45 mm. Other conditions are the same as those in Example 1.

[0070] Comparative Example 2

[0071] This comparative example provides a multi-layer co-extrusion blow-molded bottle and a preparation method thereof, which differs from Example 1 only in that the middle layer is an oxygen barrier layer made of polybutylene terephthalate, and in the preparation method, cycloolefin copolymer and polybutylene terephthalate are added to three barrels of a Novapax NSB E 650 Multilayer electric multi-layer injection blow molding machine, and multi-layer co-extrusion injection blow molding is carried out on the Novapax NSB E 650 Multilayer electric multi-layer injection blow molding machine. The screw processing temperature of polybutylene terephthalate is 257°C, and other conditions are the same as in Example 1.

[0072] Comparative Example 3

[0073] This comparative example provides a multi-layer co-extrusion blow-molded bottle and a preparation method thereof, which differs from Example 1 only in that the preparation method does not include a step of performing a heat treatment at 105°C for 5 minutes in the transmission channel to eliminate interlayer stress, and other conditions are the same as those in Example 1.

[0074] Comparative Example 4

[0075] This comparative example provides a blow-molded bottle and a preparation method thereof. The bottle wall of the blow-molded bottle is a single-layer structure, made of cycloolefin copolymer, and has a thickness of 0.9 mm.

[0076] The preparation method comprises the following steps: adding a cyclic olefin copolymer into a barrel of a Novapax NSB E650 Multilayer electric multilayer injection blow molding machine, performing extrusion injection molding and blow molding on the Novapax NSB E 650 Multilayer electric multilayer injection blow molding machine, wherein the screw processing temperature is 260°C, after injection molding, directly transferring the injection-molded preform to a blow molding mold, wherein the blow molding mold temperature is 120°C, the blow molding pressure is 9 bar, blow molding is performed, demolding is performed, a heat treatment is performed at 105°C for 5 minutes at a transmission channel, and the bottle is cooled to 25°C at room temperature to obtain the multilayer co-extrusion blow-molded bottle with a volume of 5 mL.

[0077] Comparative Example 5

[0078] This comparative example provides a blow-molded bottle and a preparation method thereof. The bottle wall of the blow-molded bottle is a single-layer structure, made of nylon 6, and has a thickness of 0.9 mm.

[0079] The preparation method comprises the following steps: adding nylon 6 into a barrel of a Novapax NSB E 650 Multilayer electric multilayer injection blow molding machine, performing extrusion injection molding and blow molding on the Novapax NSB E 650 Multilayer electric multilayer injection blow molding machine, wherein the screw processing temperature is 265° C. After injection molding, directly transferring the injection-molded preform to a blow molding mold, wherein the blow molding mold temperature is 120° C., the blow molding pressure is 9 bar, blow molding is performed, demolding is performed, heat treatment is performed at 105° C. for 5 minutes at a transmission channel, and cooling is performed to 25° C. at room temperature to obtain the multilayer co-extrusion blow-molded bottle with a volume of 10 mL.

[0080] The multilayer co-extrusion blow-molded bottles provided in Examples 1-6 and Comparative Examples 1-3 and the blow-molded bottles provided in Comparative Examples 4-5 were tested as follows.

[0081] Water vapor transmission rate: According to GB / T 31355-2014 "Test method for water vapor transmission of packages and containers", the water vapor transmission rate is tested at 38°C and 90% RH;

[0082] Oxygen permeability: According to GB / T 31354-2014 "Test method for oxygen permeability of packages and containers", the oxygen permeability is tested at 23°C and 50% RH.

[0083] Bottle making status: Observe whether the multi-layer co-extrusion blow-molded bottle has the problem of layer separation.

[0084] The test results are shown in Table 1 below.

[0085] Table 1

[0086]

[0087]

[0088] In Table 1, “ / ” means that the test was not conducted.

[0089] From the contents of Table 1, it can be seen that the water vapor permeability of the multilayer co-extrusion blow-molded bottles provided in Examples 1-6 is ≤0.00032 g / (pkg·24h), and the oxygen permeability is ≤0.0031 cm 3 / (pkg·24h·atm).

[0090] Compared with Example 1, if nylon 6 is replaced by nylon 612 (Example 6), the oxygen permeability of the prepared multi-layer co-extrusion blow-molded bottle is reduced and the performance is better.

[0091] Compared with Example 1, if the ratio of the thickness of the water vapor barrier layer to the thickness of the oxygen barrier layer is less than 4:1 (Comparative Example 1), the prepared multi-layer co-extrusion blow-molded bottle has the problem of interlayer separation.

[0092] Compared with Example 1, if nylon 6 is replaced with polybutylene terephthalate (Comparative Example 2), the problem of interlayer separation occurs in the prepared multi-layer co-extrusion blow-molded bottle.

[0093] Compared with Example 1, if no heat treatment is performed after demoulding (Comparative Example 3), the obtained multi-layer co-extrusion blow-molded bottle has the problem of interlayer separation.

[0094] Comparative Examples 4 and 5 Compared with Example 1, the oxygen barrier rate of the multi-layer co-extrusion blow-molded bottle prepared in Example 1 is much lower than the oxygen barrier rate of the blow-molded bottle made of a single-layer structure of cycloolefin copolymer material, and the water vapor barrier rate of the multi-layer co-extrusion blow-molded bottle prepared in Example 1 is much lower than the water vapor barrier rate of the single-layer structure of nylon material.

[0095] In summary, the multi-layer co-extrusion blow-molded bottle provided by the present invention has excellent water vapor barrier properties and oxygen barrier properties, and can provide a good protective barrier when packaging oxygen-sensitive drugs and foods or water vapor-sensitive drugs and foods; and can package liquid drugs to ensure stable drug concentration.

[0096] The applicant declares that the present invention illustrates the process method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned process steps, that is, it does not mean that the present invention must rely on the above-mentioned process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a multi-layer co-extrusion blow-molded bottle, characterized in that: The preparation method comprises the following steps: multi-layer co-extrusion injection blow molding of polycycloolefin compounds and nylon, demoulding and heat treatment to obtain the multi-layer co-extrusion blow-molded bottle; The multi-layer co-extrusion blow-molded bottle comprises a water vapor barrier layer and an oxygen barrier layer, wherein the water vapor barrier layer comprises a polycycloolefin compound, and the oxygen barrier layer comprises nylon, and the ratio of the thickness of the water vapor barrier layer to the thickness of the oxygen barrier layer is ≥4:

1.

2. The preparation method according to claim 1, characterized in that: The polycycloolefin compounds include cycloolefin copolymers and / or cycloolefin polymers; Preferably, the cycloolefin copolymer comprises any one or a combination of at least two of the structural compounds represented by Formula I, Formula II or Formula III; Wherein, R1 and R2 are each independently selected from hydrogen or C1-C10 alkyl; In Formula I, Formula II and Formula III, x / (x+y) is independently 0.20 to 0.90, and y / (x+y) is independently 0.10 to 0.80; Preferably, the weight average molecular weight of the cycloolefin copolymer is 50,000 to 250,000; Preferably, the melt index of the cycloolefin copolymer is 6 to 45 g / 10 min at a temperature of 260° C. and a load of 2.16 kg; Preferably, the glass transition temperature of the cycloolefin copolymer is 60-160°C.

3. The preparation method according to claim 1 or 2, characterized in that: The nylon includes any one of nylon 6, nylon 66, nylon 12 or nylon 612, or a combination of at least two of them.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The bottle wall of the multi-layer co-extrusion blow-molded bottle comprises an innermost layer, a middle layer and an outermost layer.

5. The preparation method according to claim 4, characterized in that: The innermost layer and the outermost layer are each independently a water vapor barrier layer; Preferably, the intermediate layer is an oxygen barrier layer.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The thickness of the water vapor barrier layer and the oxygen barrier layer are each independently ≥ 0.01 mm.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The multi-layer co-extrusion injection blow molding is performed using a multi-layer injection blow molding machine.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The screw processing temperature of the polycycloolefin compound in the multi-layer co-extrusion injection blow molding is 250-265°C; Preferably, the screw processing temperature of nylon in the multi-layer co-extrusion injection blow molding is 256-280°C; Preferably, the absolute value of the difference between the screw processing temperature of the polycycloolefin compound and nylon is ≤5°C; Preferably, the temperature of the blow molding mold in the multi-layer co-extrusion injection blow molding is 110-145°C; Preferably, the blow molding pressure in the multi-layer co-extrusion injection blow molding is 5 to 14 bar; Preferably, the temperature of the heat treatment is 90 to 120°C; Preferably, the heat treatment time is ≥5 min; Preferably, the multi-layer co-extrusion injection blow molding further includes a cooling step.

9. A multi-layer co-extrusion blow-molded bottle, characterized in that: The multi-layer co-extrusion blow-molded bottle is prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the multi-layer co-extrusion blow-molded bottle according to claim 9 in medicine or food packaging.

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