A modified cyclic olefin polymer barrier film material and a method for preparing the same

Abstract

The application relates to the technical field of barrier materials, and discloses a modified cyclic olefin polymer barrier film material and a preparation method thereof, which comprises the following raw material components according to 100% of total mass percentage: 50-85% of cyclic olefin polymer; 14-45% of polyethylene; and 1-5% of organic nanosilicate; the polyethylene and the organic nanosilicate are first melt-mixed to form dispersed master batches. The barrier material is prepared from a small amount of organic nanosilicate, polyethylene and cyclic olefin polymer; the dispersion effect of the organic nanosilicate in the material is excellent; the material has excellent mechanical properties and excellent oxygen and water vapor barrier properties; the single-material polymer barrier material has very excellent comprehensive performance; the material does not need to be combined with other materials in multiple layers; and the material can be widely applied in the fields of food contact materials and medical packaging materials.

Description

Technical Field

[0001] This invention relates to the field of polymer barrier materials technology, specifically to a modified cyclic olefin polymer barrier membrane material and its preparation method. Background Technology

[0002] In recent years, polymer barrier materials have played an increasingly important role in the preservation and packaging of food, pharmaceuticals, fine chemicals, and photovoltaics. Compared with traditional packaging materials, polymer barrier materials have better safety, processability, convenience, and commercial applicability. However, compared with the metallic bonds in metals and the ionic bonds in ceramics, the intermolecular forces in polymer barrier materials are weaker, resulting in poorer barrier performance against small gas molecules. Especially when preserving foods with aromatic odors or pharmaceuticals that are highly sensitive to gases, the use of general polymer barrier materials may lead to shortened shelf life or spoilage, causing economic losses or even endangering personal safety.

[0003] To improve the gas barrier properties of polymer barrier materials, various modification techniques can be employed, such as multilayer co-extrusion composite, in-situ polymerization, and nanomaterial blending. For example, Qin Yan et al. (A Multilayer Co-extruded High-Barrier Film [P]. CN214774551U) prepared a high-barrier film using a multilayer co-extrusion composite method. This method increases both the puncture resistance and flexibility of the composite film and its gas barrier performance. Multilayer composite films can combine the advantages of multiple materials and enhance barrier performance. However, the preparation process requires the use of adhesives, which is not conducive to applications such as food packaging. Furthermore, various defects of different materials can be observed during use, making them unsuitable for a wide range of scenarios.

[0004] Pei Lixia et al. (A High Oxygen Barrier Polymer Nanocomposite Film and Its Preparation Method [P]. CN109880267A) prepared various hydrophilic polymer films modified with sheet-like fillers by in-situ polymerization. The mechanical properties and oxygen barrier properties of these polymer films were significantly improved. Although in-situ polymerization helps improve the dispersion performance of fillers, some materials with harsh polymerization reaction conditions cannot be modified by in-situ polymerization. Gao Zongwang et al. (A Nanomodified High Barrier Film and Its Preparation Method [P]. CN112341696A) prepared a high-barrier nanocomposite film with good light transmittance and excellent mechanical properties by combining modified graphene and high-density polyethylene through nanomaterial blending, and also improved the waterproof and anti-fouling properties of the film. Nanomaterial blending can effectively improve the mechanical properties, thermal stability, chemical resistance, and processing performance of polymer barrier materials. This project uses nanomaterial blending to prepare a polymer film with excellent oxygen and water vapor barrier properties.

[0005] Among polymer barrier materials, cyclic olefin polymers possess advantages such as high transparency, low birefringence, low water absorption, light weight, and good chemical resistance. Although cyclic olefin polymers exhibit excellent water vapor barrier properties, their oxygen barrier properties are inferior to those of materials such as polyvinylidene chloride (PVDC) and ethylene-vinyl alcohol copolymer (EVOH). Summary of the Invention

[0006] This invention addresses the problem of insufficient oxygen barrier properties in cyclic olefin polymers by providing a modified cyclic olefin polymer barrier material. Through the combined action of modified organosilicon nanomaterials and polyethylene, the barrier properties are significantly improved, especially the oxygen barrier properties, without reducing the overall performance of the cyclic olefin polymer material.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A modified cyclic olefin polymer barrier membrane material, comprising the following raw material components by 100% of total mass:

[0009] Cyclic olefin polymers 50-85%;

[0010] Polyethylene 14-45%;

[0011] 1-5% organic nano-silicates;

[0012] The polyethylene and organic nano-silicate are first melt-blended to form a dispersion masterbatch;

[0013] The modified cyclic olefin polymer barrier membrane material has a torque value of 24-45 Nm at 180-200℃ and 10-40 r / min.

[0014] This invention utilizes a simple processing technique to blend organosilicon nanomaterials, cyclic olefin polymers, and polyethylene to prepare a cyclic olefin polymer barrier material with excellent mechanical properties and superior oxygen and water vapor barrier performance. Furthermore, the amount of organosilicon nanomaterials used is very low, avoiding the degradation of the substrate's mechanical properties caused by excessive addition. This material can be used in food contact materials and pharmaceutical packaging materials, making it a single-material polymer barrier material with excellent overall performance.

[0015] Because the amount of organic nano-silicate used is very small, its dispersion is a key factor affecting the final performance of the material. On the one hand, due to the high melt viscosity of cyclic olefin polymers, direct mixing with organic nano-silicates will result in poor dispersion. Therefore, this invention introduces polyethylene resin with low melt viscosity to reduce the overall polymer viscosity and improve the dispersibility of silicate. On the other hand, this invention requires the organic nano-silicate to be melt-blended with a small amount of polyethylene to form a dispersion masterbatch, which is more conducive to improving the dispersibility of silicate. Furthermore, this invention modifies silicate with organic modifiers. The modified silicate contains organic groups such as long-chain alkyl, silanol, alkylol, epoxy, hydrogen, vinyl, amino, or acryloyloxy groups, which have better compatibility with cyclic olefin polymers. The resulting barrier material has a torque value of 24-45 Nm at 180-200℃ and 10-40 r / min, making it more suitable for preparing membrane materials. These factors enable the material to maintain good mechanical properties and achieve excellent gas barrier properties.

[0016] The oxygen permeability of the modified cyclic olefin polymer barrier membrane material of this invention is no higher than 15 cm⁻¹. 3 ·mm / (cm 2 • day • MPa), preferably not higher than 10 cm 3 ·mm / (cm 2 (day·MPa), water vapor transmission rate not higher than 0.5cm 3 ·mm / (cm 2 ·day·MPa); tensile strength not less than 15MPa.

[0017] The cyclic olefin polymer includes one or more of COC resin, COP resin, and dicyclopentadiene linear polymer;

[0018] The COC resin refers to a COC resin obtained by copolymerizing norbornene or ethylene-imide norbornene, cyclopentadiene, and α-olefin; the COP resin refers to a COP resin obtained by homopolymerizing norbornene or ethylene-imide norbornene and then hydrogenating it; the dicyclopentadiene linear polymer refers to a linear polymer obtained by copolymerizing dicyclopentadiene and its derivatives.

[0019] The polyethylene includes one or more of the following: high-density polyethylene, low-density polyethylene, linear low-density polyethylene, metallocene polyethylene, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylate copolymer, ethylene-propylene copolymer, ethylene-octene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, and ethylene-styrene copolymer.

[0020] The organic nano-silicate is an organic nano-silicate modified from silicate by an organic modifier; the preparation process of the organic nano-silicate includes: dispersing silicate in a solvent, adding an organic modifier and stirring for modification, centrifuging and drying to obtain the organic nano-silicate. The dried organic nano-silicate is then ground and sieved before use.

[0021] The organic modifier includes one or more of alkyl quaternary ammonium salts, silane coupling agents, reactive functional group silicone oils, and epoxy compounds;

[0022] The silicates include one or more of montmorillonite, sepiolite, attapulgite, hydrotalcite, mica, kaolinite, and halloysite.

[0023] The amount of organic modifier added is 10-50% of the mass ratio of silicate; the temperature during the modification process is 60-90℃, the modification time is 2-10h, and the reaction endpoint is when no precipitate is added to the supernatant during centrifugation;

[0024] When using alkyl quaternary ammonium salts, silane coupling agents, or reactive functional group silicone oils, the solvent may include one or more of deionized water, anhydrous ethanol, acetone, and tetrahydrofuran;

[0025] When the organic modifier is an epoxy compound, the solvent includes one or more of butyl glycidyl ether, phenyl glycidyl ether, glycidyl methacrylate, anhydrous ethanol, and acetone.

[0026] Typically, the mass ratio of silicate to solvent is 1:15-30, depending on the ability to disperse the silicate.

[0027] The alkyl quaternary ammonium salt includes one or more of octadecyl dimethyl ammonium bromide, bis(octadecyl dimethyl ammonium bromide), and hexadecyl trimethyl ammonium bromide; the silane coupling agent includes one or more of KH550, KH560, and KH570; the reactive functional group silicone oil includes one or more of terminal hydroxyl silicone oil, terminal epoxy silicone oil, terminal hydrogen silicone oil, terminal vinyl silicone oil, terminal amino silicone oil, and terminal acryloyloxy silicone oil.

[0028] The epoxy compound includes one or more of the following: bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, linear phenolic epoxy resin, aliphatic glycidyl ether resin, glycidyl ester resin, alicyclic epoxy resin, heterocyclic epoxy resin, and epoxidized olefin compound.

[0029] Preferably, the organic modifier is an epoxy compound; more preferably, the epoxy compound includes one or more of E35, E42, E44, E51, E55, YDH3000, EP-4080E, F44, F51, DER732, DER736, S-508, ERR-0300, ERL-4206, TGIC, PBB-1000, etc.

[0030] In the process of silicate modification, silicate is dispersed in solvent by stirring for 15-60 minutes, preferably 30 minutes; drying is carried out at 60-80℃ to remove excess solvent and moisture.

[0031] The present invention also provides a method for preparing the modified cyclic olefin polymer barrier membrane material, comprising the following steps: Step 1, melting and kneading organic nano-silicate with a portion of polyethylene to obtain a mixture, and then melting and kneading it with a portion of polyethylene to granulate it to obtain a dispersion masterbatch;

[0032] Step 2: The dispersion masterbatch, the remaining polyethylene and cyclic olefin polymer are melt-blended and granulated to obtain granules, which are then melt-blown to obtain the modified cyclic olefin polymer barrier membrane material.

[0033] In this invention, due to the low amount of organic nano-silicate used, it is mixed with polyethylene multiple times to improve the dispersion effect and obtain optimal dispersibility, thereby improving the overall performance of the product. The polyethylene can be divided into three equal parts for use, or it can be arbitrarily divided into three parts for use; preferably, it is divided into three equal parts for use.

[0034] Preferably, the temperature for melt mixing of organic nano-silicates and polyethylene is 170-210℃; the temperature for subsequent melt mixing and granulation is 190-230℃; and the temperature for melt blowing is 220-240℃.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] This invention prepares a barrier material using a small amount of organic nano-silicates with polyethylene and cyclic olefin polymers. The organic nano-silicates in this material exhibit excellent dispersion, resulting in a material with not only superior mechanical properties but also excellent oxygen and water vapor barrier performance. It also boasts good transparency, high mechanical strength, strong puncture resistance, and outstanding oxygen barrier capability. This single-material polymer barrier material exhibits excellent comprehensive performance, eliminating the need for multi-layer composites with other materials. It can be widely used in food contact materials and pharmaceutical packaging materials. Attached Figure Description

[0037] Figure 1 The image shows the XRD pattern of the modified montmorillonite from Example 1.

[0038] Figure 2The images are scanning electron microscope (SEM) images of the standard sample of Comparative Example 1 and samples 1-3 in Example 1.

[0039] Figure 3 Transmittance test analysis diagrams for the standard sample of Comparative Example 1 and samples 1-4 in Example 1.

[0040] Figure 4 The torque of the standard sample of Comparative Example 1 and samples 1-4 in Example 1 at different speeds at 180°C is shown. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention, without departing from the spirit and scope of the invention, should be covered within the protection scope of this invention.

[0042] All raw materials used in the following specific embodiments were purchased from the market. COC was purchased from TOPAS, grade 8007F-04, with a melt index of 26-36 g / 10 min at 190℃ / 2.16 kg; LDPE was purchased from Yangzi Petrochemical-BASF Co., Ltd., grade 2420H, with a melt index of 1.7-2.2 g / 10 min at 190℃ / 2.16 kg; COP was purchased from Zeonex Corporation of Japan, grade ZEONEX K26R, with a melt index of 55 g / 10 min at 280℃ / 2.16 kg; LLDPE was purchased from Shanghai SECCO, grade LL0209AA; HDPE was purchased from Shanghai SECCO, grade HD5502FA; EVA was purchased from DuPont, USA, grade 11D542; and POE was purchased from Dow Chemical, USA, grade 907.

[0043] Example 1

[0044] Montmorillonite and deionized water were mixed in a ratio of 1g:20ml to form a slurry. The slurry was stirred magnetically at 500r / min for 30 minutes in an oil bath at 80℃. 20wt% dioctadecyl dimethyl ammonium bromide (DDAB) was added to the well-dispersed slurry. After stirring at 80℃, the mixture was cooled to room temperature, allowed to stand, and then centrifuged. The mixture was washed multiple times with deionized water and anhydrous ethanol until no precipitate was formed when 0.1M silver nitrate solution was added to the supernatant. The mixture was then dried in a drying oven at 60℃. Finally, it was mechanically pulverized and ground through a 300-mesh sieve to obtain quaternary ammonium salt modified montmorillonite OMMT.

[0045] The mass ratio of the modifier DDAB was changed to 10wt%, 30wt%, and 40wt%, and the resulting quaternary ammonium salt-modified montmorillonite OMMT and unmodified MMT were observed by XRD scanning. The results are as follows: Figure 1 As shown, the modified montmorillonite has a richer hierarchical structure, which is more conducive to improving the gas barrier properties of the matrix.

[0046] First, OMMT (20 wt% modifier) ​​and LDPE were mixed at an OMMT mass fraction of 40%, and then mixed and dispersed in an internal mixer at 170°C to prepare a high-concentration OMMT / LDPE masterbatch. Then, the masterbatch was melt-mixed and diluted with LDPE in a twin-screw extruder to promote OMMT dispersion and granulation. Next, OMMT was mixed with COC and LDPE at mass fractions of 1%, 2%, 3%, and 5%, and then melt-mixed and granulated in a twin-screw extruder at 190°C to obtain OMMT / COC barrier materials with specific formulations. The mass ratio of COC to LDPE was 3:1, meaning the mass fractions of COC in the materials were 74.25%, 73.5%, 72.75%, and 71.25%, respectively.

[0047] The barrier material was melted and blown into a film in a blown film machine at a melting temperature of 220℃ to obtain barrier films, which were named samples 1, 2, 3, and 4.

[0048] Example 2

[0049] Montmorillonite and butyl glycidyl ether were mixed in a ratio of 1g:20ml to form a slurry. The slurry was stirred magnetically at 500r / min for 30 minutes in an oil bath at 80℃. 10wt% hydrogenated bisphenol A epoxy resin (YDH3000) was added to the well-dispersed slurry. After stirring at 80℃, the mixture was cooled to room temperature, allowed to stand, and then centrifuged. The mixture was washed multiple times with deionized water and anhydrous ethanol until no precipitate was formed when 0.1M silver nitrate solution was added to the supernatant. The mixture was then dried in a drying oven at 60℃. Finally, the mixture was mechanically pulverized and ground through a 300-mesh sieve to obtain epoxy-modified montmorillonite EP-MMT.

[0050] EP-MMT and LLDPE were blended at a mass fraction of 40% EP-MMT and dispersed in an internal mixer at 190°C to prepare a high-concentration EP-MMT / LLDPE masterbatch. Then, the masterbatch was melt-blended and diluted with LLDPE in a twin-screw extruder to promote EP-MMT dispersion and granulation. Subsequently, EP-MMT was blended with COC and LLDPE at mass fractions of 1%, 2%, 3%, and 5%, and melt-blended and granulated in a twin-screw extruder at 210°C to obtain EP-MMT / COC barrier materials with specific formulations. The mass ratio of COC to LLDPE was 3:2, meaning the mass fractions of COC in the materials were 59.40%, 58.80%, 58.20%, and 57.60%, respectively.

[0051] The barrier material was melted and blown into a film in a blown film machine at a melting temperature of 220℃ to obtain barrier films, which were named samples 5, 6, 7, and 8.

[0052] Example 3

[0053] Montmorillonite and deionized water were mixed in a ratio of 1g:20ml to form a slurry. The slurry was stirred magnetically at 500r / min for 30 minutes in an oil bath at 80℃. 30wt% of terminal hydroxyl silicone oil was added to the well-dispersed slurry. After stirring at 80℃, the mixture was cooled to room temperature, allowed to stand, and then centrifuged. The mixture was washed multiple times with deionized water and anhydrous ethanol, dried in a drying oven at 60℃, and finally mechanically pulverized and ground through a 300-mesh sieve to obtain silicone oil modified montmorillonite (SI-MMT).

[0054] First, SI-MMT and ethylene-vinyl acetate copolymer (EVA) were blended at a SI-MMT mass fraction of 40% and dispersed in a Banbury mixer at 200°C to prepare a high-concentration SI-MMT / EVA masterbatch. Then, the masterbatch was melt-blended and diluted with EVA in a twin-screw extruder to promote SI-MMT dispersion and granulation. Next, SI-MMT was blended with COP and EVA at mass fractions of 1%, 2%, 3%, and 5%, and melt-blended and granulated in a twin-screw extruder at 220°C to obtain SI-MMT / COP barrier materials with specific formulations. The mass ratio of COP to EVA was 3:1, meaning the mass fractions of COP in the materials were 74.25%, 73.5%, 72.75%, and 71.25%, respectively.

[0055] The barrier material was melted and blown into a film in a blown film machine at a melting temperature of 230℃ to obtain barrier film materials, which were named 9, 10, 11, and 12.

[0056] Example 4

[0057] Attapulgite (AT) and deionized water were mixed in a ratio of 1g:20ml to form a slurry. The slurry was stirred magnetically at 500r / min for 30 minutes in an oil bath at 80℃. 40wt% octadecyl dimethyl ammonium bromide was added to the well-dispersed slurry. After stirring at 80℃, the mixture was cooled to room temperature, allowed to stand, and then centrifuged. The mixture was washed multiple times with deionized water and anhydrous ethanol until no precipitate was formed when 0.1M silver nitrate solution was added to the supernatant. The mixture was then dried in a drying oven at 60℃. Finally, it was mechanically pulverized and ground through a 300-mesh sieve to obtain quaternary ammonium salt modified halloysite, which was named sample OAT.

[0058] First, OAT was mixed with LDPE / LLDPE at a OHNTs mass fraction of 40%, with a LDPE to LLDPE mass ratio of 1:1. The mixture was then kneaded and dispersed in an internal mixer at 200°C to prepare a high-concentration OAT@LDPE / LLDPE masterbatch. Next, the masterbatch was melt-kneaded and diluted with LDPE / LLDPE in a twin-screw extruder, with an LDPE to LLDPE mass ratio of 1:1, to promote OAT dispersion and granulation. Then, OAT is blended with COC / COP and LDPE / LLDPE at mass fractions of 1%, 2%, 3%, and 5%, respectively, with a COC to COP mass ratio of 1:1. The mixture is then melt-blended and granulated using a twin-screw extruder at 220°C to obtain OAT@COC / COP barrier materials with a specific ratio. The COC / COP to LDPE / LLDPE mass ratio is 3:1, meaning that the mass fractions of COC / COP in the materials are 37.125%, 36.75%, 36.375%, and 35.625%, respectively.

[0059] The barrier material was melted and blown into a film in a blown film machine at a melting temperature of 230℃ to obtain barrier films, which were named samples 13, 14, 15, and 16.

[0060] Example 5

[0061] Attapulgite and deionized water were mixed in a ratio of 1g:20ml to form a slurry. The slurry was stirred magnetically at 500r / min for 30 minutes in an 80℃ constant temperature oil bath. 50wt% silane coupling agent (KH570) was added to the well-dispersed slurry. After stirring at 80℃, the mixture was cooled to room temperature, allowed to stand, and then centrifuged. The mixture was washed multiple times with deionized water and anhydrous ethanol, dried in a 60℃ drying oven, and finally mechanically pulverized and ground through a 300-mesh sieve to obtain silane coupling agent modified attapulgite KH-AT.

[0062] First, KH-AT and HDPE / POE were mixed at a KH-AT mass fraction of 40%, with an HDPE to POE mass ratio of 1:1. This mixture was then kneaded and dispersed in an internal mixer at 210°C to prepare a high-concentration KH-AT@HDPE / EVA masterbatch. Next, KH-AT was melt-kneaded and diluted with HDPE / POE in a twin-screw extruder to promote KH-AT dispersion and granulation. Then, KH-AT was further mixed with COP and HDPE / POE at mass fractions of 1%, 2%, 3%, and 5%, and melt-kneaded and granulated in a twin-screw extruder at 210°C to obtain KH-AT / COP barrier materials with specific formulations. The COP to HDPE / POE mass ratio was 3:1, meaning the COP mass fractions in the materials were 74.25%, 73.5%, 72.75%, and 71.25%, respectively.

[0063] The barrier material was melted and blown into a film in a blown film machine at a melting temperature of 240℃, and the resulting barrier films were named samples 17, 18, 19, and 20.

[0064] Comparative Example 1

[0065] LDPE and COC were extruded and granulated in a twin-screw extruder at 190°C to prepare a COC / LDPE standard sample, wherein the mass ratio of COC to LDPE was 3:1, that is, the mass fraction of COC in the material was 75%. The sample was melt-blown in a blown film machine at a melting temperature of 220°C to obtain a standard sample, which was named Sample 21.

[0066] Comparative Example 2

[0067] Following the preparation process conditions of Example 1, as a comparison, unmodified montmorillonite and LDPE were first mixed at a MMT mass fraction of 40%, and then mixed and dispersed in an internal mixer at 180°C to prepare a high-concentration MMT / LDPE masterbatch. Then, it was melt-mixed and diluted with LDPE in a twin-screw extruder to promote MMT dispersion and granulation. Next, it was mixed with COC and LDPE at MMT mass fractions of 1%, 2%, 3%, and 5%, and then melt-mixed and granulated in a twin-screw extruder at 200°C to obtain MMT / COC barrier materials with a specific ratio. The mass ratio of COC to LDPE was 3:1, meaning the mass fractions of COC in the materials were 74.25%, 73.5%, 72.75%, and 71.25%, respectively.

[0068] The barrier material was melted and blown into a film in a blown film machine at a melting temperature of 220℃ to obtain control film samples, which were named samples 22, 23, 24, and 25.

[0069] Comparative Example 3

[0070] Following the process of Example 4, as a comparison, the same method was used to modify cyclic olefin polymers with unmodified attapulgite to prepare barrier materials and membranes. The specific steps are as follows:

[0071] First, attapulgite and LDPE / LLDPE are blended at 40% AT by mass, with a LDPE to LLDPE mass ratio of 1:1. This mixture is then blended and dispersed in an internal mixer at 210°C to prepare a high-concentration AT@LDPE / LLDPE masterbatch. Next, the masterbatch is melt-blended and diluted with LDPE / LLDPE in a twin-screw extruder to promote AT dispersion and granulation. Then, it is blended with COC / COP and LDPE / LLDPE at AT mass fractions of 1%, 2%, 3%, and 5%, respectively, with a COC to COP mass ratio of 1:1. This mixture is then melt-blended and granulated in a twin-screw extruder at 230°C to obtain AT@COC / COP barrier materials with specific proportions. The COC / COP to LDPE / LLDPE mass ratio is 3:1, meaning the COC / COP mass fractions in the materials are 74.25%, 73.5%, 72.75%, and 71.25%, respectively.

[0072] The barrier material was melted and blown into a film in a blown film machine at a melting temperature of 240℃ to obtain control film samples, which were named samples 26, 27, 28, and 29.

[0073] Comparative Example 4

[0074] Organomontmorillonite was prepared according to the raw material ratio of Example 1; OMMT and COC resin were mixed in proportions of 1%, 2%, 3%, and 5% by mass of OMMT, and then melt-mixed and granulated by a twin-screw extruder at 210°C to obtain OMMT / COC barrier materials with a certain ratio.

[0075] The barrier material was melted and blown into a film in a blown film machine at a melting temperature of 230°C. However, due to the high viscosity of the COC resin, blown film samples could not be obtained.

[0076] Comparative Example 5

[0077] Organomontmorillonite was prepared according to the raw material ratio in Example 1; then OMMT was mixed with LDPE and COC resin at a mass fraction of 1%, 2%, 3%, and 5% of OMMT, and the mixture was melt-mixed and granulated at 190°C using a twin-screw extruder to obtain OMMT / COC barrier materials with a certain ratio, wherein the mass ratio of COC to LDPE was 3:1, that is, the mass fraction of COC in the materials was 74.25%, 73.5%, 72.75%, and 71.25%, respectively.

[0078] The barrier material was melted and blown into a film in a blown film machine at a melting temperature of 220°C to obtain barrier film materials, which were named Comparative Examples 30, 31, 32, and 33.

[0079] The microstructure of standard sample 21 prepared in Comparative Example 1 and samples 1-3 prepared in Example 1 were observed, and their SEM images are shown below. Figure 2As shown, the modified montmorillonite is uniformly dispersed in the matrix without agglomeration.

[0080] Similarly, transparency tests were performed on the standard sample of Example 1 and samples 1-4 of Example 1. The light transmittance test analysis is as follows: Figure 3 As shown, even after adding modified silicate, the transparency of the film material remains high.

[0081] The torque data of the standard sample in Comparative Example 1 and samples 1-4 in Example 1 are as follows: Figure 4 As shown, by observing the viscosity of the material through torque, it can be seen that the final membrane material has a low viscosity and is suitable for preparing membrane materials.

[0082] The oxygen barrier performance of cyclic olefin polymer barrier materials is expressed by the membrane's permeability. Lower permeability indicates better oxygen barrier performance, while higher permeability indicates poorer oxygen barrier performance. Mechanical properties are reflected by tensile strength; higher tensile strength indicates better mechanical properties.

[0083] The oxygen permeability of the cyclic olefin polymer barrier materials and membranes prepared in each embodiment was tested using a differential pressure gas permeation apparatus, and the results are listed in Table 1. The water vapor permeability of the cyclic olefin polymer barrier materials and membranes prepared in each embodiment was tested using an infrared detection water vapor permeation apparatus, and the results are listed in Table 2. The tensile strength of the cyclic olefin polymer barrier materials and membranes prepared in each embodiment was tested using a universal testing machine, and the test results are listed in Table 3.

[0084] The performance test standards are as follows: oxygen transmission rate test: according to GB / T1038-2000 test standard; water vapor transmission rate test: according to GB / T 26253-2010 test standard; tensile strength test: according to standard GB / T1040-2006; light transmittance test: according to GB / T 2410-2008 test standard.

[0085] Table 1 Comparison of Oxygen Barrier Performance of Cycloolefin Polymer Barrier Membranes

[0086]

[0087] Table 2 Comparison of Water Vapor Barrier Performance of Cycloolefin Polymer Barrier Membranes

[0088]

[0089] Table 3 Comparison of mechanical properties of cyclic olefin polymer barrier films

[0090]

[0091]

[0092] As shown in Tables 1-3, Sample 21 is a COC / LDPE standard film. In Comparative Example 2, Samples 22-25 are composite materials made from unmodified MMT, polyethylene, and COC. Compared to the standard samples, their oxygen permeability only decreased slightly, water vapor permeability decreased somewhat, and mechanical properties remained largely unchanged. Samples 1-4 of Example 1, under the same process conditions, showed superior oxygen permeability. Similarly, Samples 26-29 of Comparative Example 3, due to the lack of silicate modification, showed only a small decrease in oxygen permeability. Example 4 (Samples 13-16), using the same raw materials, showed even better results. Different silicates or the same silicate modified with different modifiers resulted in slightly different effects.

Claims

1. A modified cyclic olefin polymer barrier membrane material, characterized in that, Based on 100% of the total mass, it includes the following raw material components: Cyclic olefin polymers 50-85%; Polyethylene 14-45%; Organic nano-silicates 1-5%; The polyethylene and organic nano-silicate are first melt-blended to form a dispersion masterbatch; The modified cyclic olefin polymer barrier membrane material has a torque value of 24-45 Nm at 180-200℃ and 10-40 r / min. The cyclic olefin polymer includes one or more of COC resin, COP resin, and dicyclopentadiene linear polymer; The organic nano silicate is an organic nano silicate modified by an organic modifier; the organic modifier is any one of bis(octadecyldimethylammonium bromide), YDH3000, or hydroxyl-terminated silicone oil. The preparation process of the organic nano silicate includes: dispersing silicate in a solvent, adding an organic modifier and stirring to modify it, and then centrifuging and drying to obtain the organic nano silicate; The method for preparing the modified cyclic olefin polymer barrier membrane material includes the following steps: Step 1: The organic nano-silicate is melt-blended with a portion of polyethylene to obtain a mixture, which is then melt-blended with a portion of polyethylene and granulated to obtain a dispersion masterbatch; Step 2: The dispersion masterbatch, the remaining polyethylene and cyclic olefin polymer are melt-blended and granulated to obtain granules, which are then melt-blown to obtain the modified cyclic olefin polymer barrier film material; The oxygen permeability of the modified cyclic olefin polymer barrier membrane material is no higher than 15 mm·cm. 3 / (m 2 (day·MPa), water vapor transmission rate not higher than 0.5 mm·g / (m 2 • day • MPa); tensile strength not less than 15 MPa.

2. The modified cyclic olefin polymer barrier membrane material according to claim 1, characterized in that, The COC resin refers to a COC resin obtained by copolymerizing norbornene or ethylene-imide norbornene, cyclopentadiene, and α-olefin; the COP resin refers to a COP resin obtained by homopolymerizing norbornene or ethylene-imide norbornene and then hydrogenating it; the dicyclopentadiene linear polymer refers to a linear polymer obtained by copolymerizing dicyclopentadiene and its derivatives.

3. The modified cyclic olefin polymer barrier membrane material according to claim 1, characterized in that, The polyethylene includes one or more of the following: high-density polyethylene, low-density polyethylene, linear low-density polyethylene, metallocene polyethylene, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylate copolymer, ethylene-propylene copolymer, ethylene-octene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, and ethylene-styrene copolymer.

4. The modified cyclic olefin polymer barrier membrane material according to claim 1, characterized in that, The amount of organic modifier added is 10-50% of the mass ratio of silicate; the temperature during the modification process is 60-90℃, the modification time is 2-10h, and the reaction endpoint is when no precipitate is added to the supernatant during centrifugation; When the organic modifier is hydroxyl-terminated silicone oil, the solvent includes one or more of deionized water, anhydrous ethanol, acetone, and tetrahydrofuran; When the organic modifier is YDH3000, the solvent includes one or more of butyl glycidyl ether, phenyl glycidyl ether, glycidyl methacrylate, anhydrous ethanol, and acetone.

5. The modified cyclic olefin polymer barrier membrane material according to claim 1, characterized in that, The silicates include one or more of montmorillonite, sepiolite, attapulgite, hydrotalcite, mica, kaolinite, and halloysite.

6. The method for preparing the modified cyclic olefin polymer barrier membrane material according to claim 1, characterized in that, Including the following steps: Step 1: The organic nano-silicate is melt-blended with a portion of polyethylene to obtain a mixture, which is then melt-blended with a portion of polyethylene and granulated to obtain a dispersion masterbatch; Step 2: The dispersion masterbatch, the remaining polyethylene and cyclic olefin polymer are melt-blended and granulated to obtain granules, which are then melt-blown to obtain the modified cyclic olefin polymer barrier membrane material.

7. The method for preparing the modified cyclic olefin polymer barrier membrane material according to claim 6, characterized in that, The melting mixing temperature is 170-210℃, the melting mixing and granulation temperature is 190-230℃, and the melting blown film temperature is 220-240℃.

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