Chopped glass fiber reinforced polyethylene composite material with high barrier property and preparation method thereof

Abstract

The invention relates to a chopped glass fiber reinforced polyethylene composite material with high barrier property and a preparation method thereof. The chopped glass fiber reinforced polyethylene composite material comprises the following components in parts by weight: 80-160 parts of polyethylene; 15 to 65 parts of chopped glass fiber; 1 to 15 parts of compatilizer; and 15-50 parts of an ethylene / vinyl alcohol copolymer. The preparation method comprises the following steps: performing vacuum drying on the ethylene / vinyl alcohol copolymer, and proportioning the ethylene / vinyl alcohol copolymer with the polyethylene and the compatilizer; uniformly mixing in a high-speed stirrer, and adding into a hopper of a double-screw extruder; and laterally feeding chopped glass fibers, blending, extruding, cooling, granulating and drying. Compared with the prior art, the high-barrier chopped glass fiber reinforced polyethylene composite material prepared by a one-step method provided by the invention is simple in preparation process and high in operability, and the manufacturing cost is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials technology, and in particular to a short-cut glass fiber reinforced polyethylene composite material with high barrier properties and its preparation method. Background Technology

[0002] Composite materials occupy a very important position in the field of new materials, playing a crucial role in promoting the high-tech modernization of military and civilian fields worldwide, and therefore have received much attention in recent years. As a type of polymer-based composite material, thermoplastic composites, compared with thermosetting resin-based composites, possess unique advantages such as high toughness, good damage resistance, short molding time, and the ability to recycle waste materials, making them more suitable for large-scale production.

[0003] However, with the emergence of more complex working conditions and application environments, the demand for high performance, multifunctionality, lightweighting, and low cost is gradually increasing, such as excellent mechanical properties, electrical properties, and durability. Therefore, the development of fiber-reinforced resin matrix composites has become one of the research hotspots. Composites with added fibers exhibit high mechanical strength, good impact resistance, environmentally friendly production processes, and recyclability, making them ideal materials for lightweight product manufacturing and clean energy applications. Short fiber reinforced thermoplastic resin matrix composites generally use general-purpose thermoplastic resins such as polypropylene, polyethylene, and polystyrene as the matrix material. The reinforcing material is primarily glass fiber. These thermoplastic resin-based composite materials have simple molding processes and short manufacturing cycles, but they lack multifunctional characteristics, such as temperature resistance and barrier properties, limiting their expansion into a wider range of applications. In engineering applications, the requirements for the barrier properties of composite materials are gradually increasing. Gas storage tanks commonly used in the chemical industry, while serving as pressure vessels, also require excellent gas barrier properties. Similarly, oil and gas pipelines and automotive fuel tanks require superior mechanical and barrier properties.

[0004] CN 112708209 A discloses a lightweight, high-strength glass fiber reinforced polypropylene composite material and its preparation method. Compared to commercially available short glass fiber reinforced materials of the same grade, the glass fiber reinforced polypropylene composite material prepared using this method employs an ultrasonic treatment process. This significantly improves the flowability of the matrix material and reduces its annual stress, ensuring good impregnation while also ensuring consistent glass fiber orientation due to the treatment process, thus greatly enhancing material performance. The final product possesses high mechanical properties and can be used as a lightweight material, but it lacks barrier properties, thus failing to meet the needs of many application areas.

[0005] CN 114874526 A discloses a high-barrier composite material and its preparation method. The high-barrier composite material is prepared by melt blending of the following raw materials: HDPE resin, MPA resin, compatibilizer, nano-graphite flakes, silane coupling agent, and antioxidant. The MPA resin is prepared by melt extrusion using PA6 resin, toughening agent, initiator, and antioxidant. The high-barrier composite material exhibits high barrier properties against various solvents and gases, and can be used for packaging easily leaky items such as pesticides, pharmaceuticals, and gasoline, with a wide range of applications. The preparation method is relatively simple, but the finished product has low mechanical strength and poor pressure resistance, making it unsuitable for applications such as gas storage tanks and oil and gas pipelines.

[0006] CN 116394612 A discloses a high-barrier polyethylene composite film and its preparation method, which is made by co-extrusion blown film forming an inner layer, a middle layer, and an outer layer. The raw materials of the middle layer include: polyethylene, maleic anhydride-grafted polyethylene / mica sheet composite material, polyolefin-coated modified nanoparticles, kaolin / modified nano-alumina composite material, modified cyclodextrin / nano-zinc oxide composite material, and a crosslinking agent. The middle layer is formed by blending and granulating various composite materials and crosslinking agents, and then co-extruding and blown film forming it with the inner and outer layers to form a composite film, which can improve the mechanical strength and barrier properties of the composite film. However, the preparation process is complex and the production cycle is long, which is not conducive to industrial production.

[0007] As can be seen from the above, current composite materials with barrier properties often have low mechanical properties and complex manufacturing processes; composite materials with high mechanical properties do not inherently possess barrier properties. Therefore, there is an urgent need to invent a polyethylene-based composite material that is simple to manufacture and possesses both high strength and high barrier properties. Summary of the Invention

[0008] This invention addresses the problems of poor mechanical properties in barrier composite materials and low barrier properties in high-mechanical-performance composite materials by employing a simpler one-step process to prepare high-strength, high-barrier polyethylene-based composite materials, thus meeting the application conditions of more complex working conditions in various fields.

[0009] The objective of this invention can be achieved through the following technical solutions:

[0010] The first aspect of this invention provides a chopped glass fiber reinforced polyethylene composite material with high barrier properties, comprising the following components in parts by weight:

[0011] 80-160 parts of polyethylene

[0012] 15-65 parts chopped glass fiber

[0013] 1-15 parts compatibilizer

[0014] 15-50 parts of ethylene / vinyl alcohol copolymer.

[0015] Furthermore, it includes the following components in parts by weight:

[0016] 80-150 parts of polyethylene

[0017] 31-61 parts chopped glass fiber

[0018] 2-15 parts compatibilizer

[0019] 20-38 parts of ethylene / vinyl alcohol copolymer.

[0020] Furthermore, the polyethylene is high-density polyethylene with a melt index of 0.29–60 g / 10 min (190 °C, 2.16 kg).

[0021] Furthermore, the chopped glass fiber is chopped glass fiber yarn, the fiber type is alkali-free glass fiber (E-Glass), and the fiber monofilament diameter is 5-17μm.

[0022] Furthermore, the compatibilizer is maleic anhydride-grafted high-density polyethylene (PE-g-MAH), with a maleic anhydride grafting rate of not less than 0.8% and a melt index > 1 g / 10 min (190 °C, 2.16 kg).

[0023] Furthermore, the density of the ethylene / vinyl alcohol copolymer is ≥1.10 g / cm³. 3 Ethylene content ≥25 mol%, melt index ≥1.5 g / 10 min (190℃, 2.16 kg), melting point 160~220℃, oxygen permeability ≤3 cm³ 3 ·20μm / m 2 ·day·atm (20℃×65%RH, ISO 14663-2).

[0024] A second aspect of the present invention provides a method for preparing a short-cut glass fiber reinforced polyethylene composite material with high barrier properties as described above, comprising the following steps:

[0025] S1: The ethylene / vinyl alcohol copolymer is dried under vacuum, and then mixed with polyethylene and compatibilizer in a high-speed mixer according to the weight ratio. The mixture is then added to the hopper of a twin-screw extruder.

[0026] S2: Short glass fibers are added from the side feed port of the twin-screw extruder, and the blending process is carried out under vacuum conditions;

[0027] S3: The blend is extruded through a twin-screw extruder, cooled in a water tank, and then pelletized by a pelletizer to prepare reinforced polyethylene pellets with a length of 2-4 mm. After drying, the pellets are sieved, and the fiber weight content is 20-40%.

[0028] Furthermore, in S1, the ethylene / vinyl alcohol copolymer is dried at 90°C for 8 hours under vacuum.

[0029] Furthermore, the feeding frequency of the twin-screw extruder is 5-20Hz, and the screw speed is 40-300rpm.

[0030] Furthermore, the temperatures of each section of the twin-screw extruder are 190℃, 200℃, 210℃, 230℃, and 240℃, respectively.

[0031] Furthermore, by applying ultrasonic waves of a preset frequency to the die head position of the twin-screw extruder, the flow direction of the glass fibers is made more consistent, thereby improving the tensile and impact resistance of the finished material.

[0032] Compared with the prior art, the present invention has the following technical advantages:

[0033] 1) This invention proposes a one-step method for preparing high-barrier chopped glass fiber reinforced polyethylene composite materials. The preparation process is simple, highly operable, and greatly reduces manufacturing costs.

[0034] 2) The composite materials of this invention have broad application prospects, particularly in the automotive, electrical appliance, municipal engineering, and military industries. These products not only exhibit excellent mechanical properties, such as high tensile strength and impact resistance, but also possess outstanding gas and oil barrier properties, giving them a significant advantage in applications requiring high barrier performance. For example, in the automotive industry, this material can be used to manufacture lightweight and durable components, improving fuel efficiency and vehicle lifespan; in the packaging field, it can be used to manufacture containers with high barrier properties, protecting contents from the external environment. Through the innovative application of this material, higher-performance and lower-cost solutions can be provided to related industries. Attached Figure Description

[0035] Figure 1 This is a flowchart of the preparation method of the short-cut glass fiber reinforced polyethylene composite material with high barrier properties in this invention. Detailed Implementation

[0036] The chopped glass fiber reinforced polyethylene composite material with high barrier properties described in this invention comprises the following components by weight: 80-160 parts polyethylene, 15-65 parts chopped glass fiber, 1-15 parts compatibilizer, and 15-50 parts ethylene / vinyl alcohol copolymer. This barrier-resistant composite material not only improves material strength but also possesses excellent gas and oil barrier properties.

[0037] Preferably, the polyethylene is high-density polyethylene with a melt index of 0.29 to 60 g / 10 min (190°C, 2.16 kg).

[0038] In specific implementation, the glass fiber is chopped glass fiber yarn, and its fiber type is alkali-free glass fiber (E-Glass), with a single filament diameter of 5-17μm.

[0039] In specific implementation, the compatibilizer is maleic anhydride-grafted high-density polyethylene (PE-g-MAH), with a maleic anhydride grafting rate of not less than 0.8% and a melt index > 1g / 10min (190℃, 2.16kg).

[0040] In specific implementation, the density of the ethylene / vinyl alcohol copolymer is ≥1.10 g / cm³. 3 Ethylene content ≥25 mol%, melt index ≥1.5 g / 10 min (190℃, 2.16 kg), melting point 160~220℃, oxygen permeability ≤3 cm³ 3 ·20μm / m 2 ·day·atm (20℃×65%RH, ISO 14663-2).

[0041] For specific implementation details, please refer to the preparation process of the high-barrier short glass fiber reinforced polyethylene composite material. Figure 1 It includes the following main steps:

[0042] (1) After drying the ethylene / vinyl alcohol copolymer at 90°C in a vacuum environment for 8 hours, it is mixed with polyethylene and compatibilizer in a high-speed mixer according to the weight ratio and then added to the hopper of a twin-screw extruder.

[0043] (2) Add chopped glass fibers from the side feed port and carry out the blending process under vacuum conditions;

[0044] (3) The extruder sections are 190℃, 200℃, 210℃, 230℃ and 240℃ respectively. After cooling in a water tank, the extruder is pelletized by a pelletizer to prepare reinforced polyethylene pellets with a length of 2-4mm. After drying, the pellets are sieved, and the fiber weight content is 20-40%.

[0045] In step (1), the feeding frequency of the twin-screw extruder is 5-20Hz, and the screw speed is 40-300rpm. More preferably, by applying ultrasonic waves of a certain frequency to the die head, the glass fiber flow direction is made more uniform, which can effectively improve the tensile and impact resistance of the finished material.

[0046] The short-cut glass fiber reinforced polyethylene composite material prepared by this invention has high barrier properties. The short glass fibers are well impregnated with polyethylene. It not only has high mechanical properties, but also barrier properties, and can be widely used in the field of injection molded parts.

[0047] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Any preparation methods, materials, structures, or compositional ratios not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0048] Table 1. Component proportions of each embodiment

[0049] Example Example 1 Example 2 Example 3 Comparative Example 1 polyethylene 80 100 150 80 Short-cut glass fiber 31 40 61 31 compatibilizer 2 28 15 2 Ethylene / vinyl alcohol copolymer 20 25 38 0

[0050] Example 1

[0051] The 80 parts of polyethylene had a melt index of 6.0 g / 10 min;

[0052] The 31 glass fiber types are short-cut alkali-free glass fibers that have been treated with coupling agent;

[0053] The two compatibilizers are high-density polyethylene-maleic anhydride grafted;

[0054] The 20 parts of ethylene / vinyl alcohol copolymer;

[0055] According to the published preparation method and processing technology, the glass fiber content in the high-barrier short glass fiber reinforced polyethylene composite granules was 30±3wt%. The granules were tested after sample preparation, and the test results are shown in Table 2.

[0056] Example 2

[0057] The melt index of the 100 parts of polyethylene is 7.0 g / 10 min;

[0058] The 40 glass fibers were short-cut alkali-free glass fibers that had been impregnated with a coupling agent.

[0059] The 28 compatibilizers were high-density polyethylene-maleic anhydride grafted;

[0060] The 25 parts of ethylene / vinyl alcohol copolymer;

[0061] According to the published preparation method and processing technology, the glass fiber content in the high-barrier short glass fiber reinforced polyethylene composite granules was 30±3wt%. The granules were tested after sample preparation, and the test results are shown in Table 2.

[0062] Example 3

[0063] The 150 parts of polyethylene had a melt index of 60 g / 10 min;

[0064] The 61 glass fiber types are short-cut alkali-free glass fibers that have been treated with coupling agent;

[0065] The 15 compatibilizers are high-density polyethylene-maleic anhydride grafted;

[0066] The 38 parts of ethylene / vinyl alcohol copolymer;

[0067] According to the published preparation method and processing technology, the glass fiber content in the high-barrier short glass fiber reinforced polyethylene composite granules was 30±3wt%. The granules were tested after sample preparation, and the test results are shown in Table 2.

[0068] Comparative Example 1

[0069] The 80 parts of polyethylene had a melt index of 6 g / 10 min;

[0070] The 31 glass fiber types are short-cut alkali-free glass fibers that have been treated with coupling agent;

[0071] The two compatibilizers are high-density polyethylene-maleic anhydride grafted;

[0072] According to the published preparation method and processing technology, the glass fiber content in the high-barrier short glass fiber reinforced polyethylene composite granules was 30±3wt%. The granules were tested after sample preparation, and the test results are shown in Table 2.

[0073] Table 2 illustrates that the embodiments have significant advantages over Comparative Example 1 in terms of two key performance indicators: tensile strength and oxygen permeability. This is due to the specific material formulation or preparation process used in the embodiments, which improves the mechanical strength and barrier properties of the materials.

[0074] Table 2. Performance comparison results of each embodiment and comparative example.

[0075]

[0076] *1 Tensile testing standard: GB / T 1040.2—2006;

[0077] *2Oxygen permeability determination: The blended sample was hot-pressed into a 1 mm thick sheet with an area of ​​12 × 12 cm using a flat vulcanizing press. 2 The oxygen permeability of the thin film was determined using the differential pressure method and a gas permeation analyzer.

[0078] Test standard: GB / T 1038.1-2022.

[0079] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A short glass fiber reinforced polyethylene composite having high barrier properties, characterized in that, The following components by weight parts: Polyethylene 80-160 parts Chopped glass fiber 15-65 parts Compatibilizer 1-15 parts Ethylene / vinyl alcohol copolymer 15-50 parts.

2. The short glass fiber reinforced polyethylene composite material with high barrier property according to claim 1, characterized in that, The following components by weight parts: Polyethylene 80-150 parts Chopped glass fiber 31-61 parts Compatibilizer 2-15 parts Ethylene / vinyl alcohol copolymer 20-38 parts.

3. The short glass fiber reinforced polyethylene composite material with high barrier property according to claim 1, characterized in that, The polyethylene is high-density polyethylene, melt index 0.29-60 g / 10 min (190℃, 2.16 kg).

4. The short glass fiber reinforced polyethylene composite material with high barrier property according to claim 1, characterized in that, The chopped glass fiber is glass fiber chopped yarn, fiber type is alkali-free glass fiber (E-glass), fiber monofilament diameter 5-17 μm.

5. The short glass fiber reinforced polyethylene composite material with high barrier property according to claim 1, characterized in that, The compatibilizer is maleic anhydride grafted high-density polyethylene (PE-g-MAH), its maleic anhydride grafting grafting rate is not less than 0.8%, its melt index is >1 g / 10 min (190℃, 2.16 kg).

6. The short glass fiber reinforced polyethylene composite material with high barrier property according to claim 1, characterized in that, said ethylene / vinyl alcohol copolymer has a density > 1.10 g / cm 3 an ethylene content > 25 mol%, a melt index > 1.5 g / 10 min (190°C, 2.16 kg), a melting point of 160 to 220°C, an oxygen transmission rate < 3 cm 3 · 20 μm / m 2 · day atm (20°C x 65% RH, ISO 14663-2).

7. A process for the production of a short glass fiber reinforced polyethylene composite material having high barrier properties according to any one of claims 1 to 6, characterized in that, The following steps are included: S1: dry treatment of ethylene / vinyl alcohol copolymer in a vacuum environment, put polyethylene and compatibilizer in a high-speed mixer according to the weight ratio, stir uniformly, add the mixture to the hopper of a twin-screw extruder; S2: add chopped glass fiber from the side feeding port of the twin-screw extruder, and perform blending under vacuum during the process; S3: extrude the blended material through the twin-screw extruder, cool it in a water tank, and cut it into granules by a granulator to prepare reinforced polyethylene granules with a length of 2-4 mm, and sieve after drying, wherein the fiber weight content is 20-40%.

8. The short glass fiber reinforced polyethylene composite material with high barrier property according to claim 7, characterized in that, In S1, the ethylene / vinyl alcohol copolymer is dried at 90℃ for 8 hours in a vacuum environment.

9. The short glass fiber reinforced polyethylene composite material with high barrier property according to claim 7, characterized in that, The feeding frequency of the twin-screw extruder is 5-20 Hz, and the screw rotation speed is 40-300 rpm; The temperature of each section of the twin-screw extruder is 190℃, 200℃, 210℃, 230℃, and 240℃, respectively.

10. The short glass fiber reinforced polyethylene composite material with high barrier property according to claim 8, characterized in that, By applying a preset frequency of ultrasonic waves to the head position of the twin-screw extruder, the glass fiber flow tends to be uniform, thereby improving the tensile and impact resistance of the finished material.

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