Foamed polyethylene composite material as well as preparation method and application thereof

Abstract

The invention provides a foamed polyethylene composite material as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The foamed polyethylene composite material comprises the following components in parts by weight: 92-100 parts of high-density polyethylene, 1-5 parts of carbomer and 0.4-2 parts of a processing aid. According to the foamed polyethylene composite material disclosed by the invention, high-density polyethylene is taken as a matrix, and carbomer is added, so that the foamed polyethylene composite material has a relatively good foaming degree.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to a foamed polyethylene composite material, a preparation method thereof and an application thereof. Background Art

[0002] With the rapid development of the new energy vehicle market, safety, driving range, and comfort have become the key concerns of consumers. Due to characteristics such as low density and low cost, polymer foamed materials have become an ideal choice for components such as automotive air ducts, doors, and roofs of new energy vehicles.

[0003] High-density polyethylene (HDPE) is a thermoplastic resin with high crystallinity and non-polarity, having excellent mechanical properties and processing properties. It has good strength, toughness, and impact resistance. Compared with traditional HDPE, foamed HDPE can greatly reduce the material specific gravity, thereby reducing costs, and at the same time has excellent impact performance. However, the foaming degree of foamed HDPE is low. Therefore, how to improve the foaming degree of foamed HDPE is an urgent problem to be solved at present. Summary of the Invention

[0004] The purpose of the present disclosure is to overcome the deficiencies of the prior art, and provides a foamed polyethylene composite material, a preparation method thereof and an application thereof. The foamed polyethylene composite material has a lower specific gravity and a higher foaming degree.

[0005] To achieve the above purpose, the technical solution adopted by the present disclosure is: In the first aspect, a foamed polyethylene composite material is provided, which includes the following components in parts by weight: 93-99 parts of high-density polyethylene, 1-5 parts of carbomer, and 0.4-2 parts of processing aid.

[0006] In some embodiments, the number-average molecular weight of the carbomer is 700,000-4,000,000.

[0007] In some embodiments, the melt flow rate of the high-density polyethylene at 190 °C and 2.16 kg is 1-60 g / 10 min.

[0008] In some embodiments, the processing aid is a lubricant and / or an antioxidant.

[0009] In some embodiments, the lubricant is at least one of low molecular weight ester lubricants, metal soap lubricants, stearic acid composite ester lubricants, and amide lubricants.

[0010] In some embodiments, the antioxidant is at least one of hindered phenol antioxidants, hindered amine antioxidants, phosphite antioxidants, and thioester antioxidants.

[0011] In a second aspect, a method for preparing the foamed polyethylene composite material is provided, comprising the following steps:

[0012] Mix high-density polyethylene, carbomer and processing aids in proportion and uniformly, then add 0.5 - 2 parts by weight of a chemical blowing agent, and mix uniformly to obtain a premix;

[0013] Add the premix into a screw extruder for melt extrusion and granulation to obtain the foamed polyethylene composite material.

[0014] In some embodiments, the chemical blowing agent includes an azo blowing agent and / or a carbonate blowing agent.

[0015] In a third aspect, an application of the foamed polyethylene composite material in preparing automotive parts is provided.

[0016] In a fourth aspect, an automotive part is provided, comprising the foamed polyethylene composite material.

[0017] Compared with the prior art, the beneficial effects of the present disclosure are as follows: The foamed polyethylene composite material of the present invention uses high-density polyethylene as the matrix and adds carbomer. During the process of the foamed polyethylene composite material, it promotes the foaming of high-density polyethylene, and obtains a foamed polyethylene composite material with uniform and dense cell structure and high foaming degree. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a scanning electron microscope image of the cross-section of the foamed polyethylene obtained in Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] To facilitate the understanding of the present disclosure, the present disclosure will be described more comprehensively below. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosed content of the present disclosure more thorough and comprehensive.

[0020] As used herein, the term:

[0021] "Prepared from..." is synonymous with "comprising". As used herein, the terms "comprising", "including", "having", "containing" or any other variation thereof are intended to cover non-exclusive inclusion. For example, a composition, step, method, article or device containing the listed elements is not necessarily limited to those elements, but may include other elements not explicitly listed or elements inherent to such composition, step, method, article or device.

[0022] The connective "consisting of" excludes any unrecited element, step, or component. If used in a claim, this phrase renders the claim closed, excluding materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause within the body of a claim rather than immediately following the subject, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0023] When an equivalent, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values and lower preferred values, this should be understood to specifically disclose all ranges formed by any pairing of any upper range limit or preferred value with any lower range limit or preferred value, whether or not that range is separately disclosed. For example, when the range "1 - 5" is disclosed, the described range should be interpreted to include ranges "1 - 4", "1 - 3", "1 - 2", "1 - 2 and 4 - 5", "1 - 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its end values and all integers and fractions within that range.

[0024] In these examples, unless otherwise specified, the parts and percentages are by mass.

[0025] "Parts by mass" refers to the basic measurement unit representing the mass ratio relationship of multiple components. 1 part can represent any unit mass, such as 1 g or 2.689 g, etc. If we say that the mass part of component A is a parts and the mass part of component B is b parts, it means the mass ratio of component A to component B is a:b. Or, it means the mass of component A is aK and the mass of component B is bK (K is any number representing a multiple factor). It should not be misunderstood that, different from the number of parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0026] "And / or" is used to indicate that either or both of the stated circumstances may occur. For example, A and / or B includes (A and B) and (A or B).

[0027] To solve the problem of low foaming degree of foamed polyethylene in the prior art.

[0028] The present invention provides a foamed polyethylene composite material, comprising the following components in parts by weight: 92 - 100 parts of high - density polyethylene, 1 - 5 parts of carbomer, and 0.4 - 2 parts of processing aid.

[0029] In different embodiments, the parts by weight of the high - density polyethylene can be, but are not limited to, 93 parts, 94 parts, 95 parts, 96 parts, 97 parts, 98 parts, 99 parts;

[0030] In different embodiments, the parts by weight of the carbomer can be, but are not limited to, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts;

[0031] In different embodiments, the parts by weight of the carbomer can be, but are not limited to, 0.5 part, 0.7 part, 0.9 part, 1.1 part, 1.3 part, 1.5 parts;

[0032] In different embodiments, the parts by weight of the processing aid can be, but are not limited to, 0.4 part, 0.6 part, 0.8 part, 1.0 part, 1.2 part, 1.4 part, 1.6 part, 1.8 part, 2.0 parts.

[0033] The foamed polyethylene composition of the present invention uses high-density polyethylene as the matrix, adds carbomer, and promotes the foaming of high-density polyethylene during the process of preparing the foamed polyethylene composite material, so as to obtain a foamed polyethylene composite material with both dense cell structure and high foaming degree.

[0034] In some embodiments, the number-average molecular weight of the carbomer is 700,000 - 4,000,000, and can be, for example, but not limited to, 700,000, 900,000, 1,100,000, 1,300,000, 1,500,000, 2,000,000, 2,500,000, 3,000,000, 3,500,000, 4,000,000; preferably 1,200,000 - 2,000,000; the testing method is gel permeation chromatography (GPC).

[0035] Optionally, the carbomer is formed by cross-linking pentaerythritol with acrylic acid, or by cross-linking sucrose allyl ether, etc. with acrylic acid. Preferably, it is formed by cross-linking pentaerythritol with acrylic acid. When the number-average molecular weight of the carbomer is 700,000 - 4,000,000, the foaming effect is better. When the number-average molecular weight of the carbomer is 1,200,000 - 2,000,000, the foaming degree and tensile strength of the foamed polyethylene composite material can be further improved; if the number-average molecular weight of the carbomer is too small, the thickening effect of the carbomer is not obvious, the melt strength of high-density polyethylene is insufficient, which is not conducive to the formation of bubbles, resulting in a decrease in the tensile strength and foaming degree of the foamed polyethylene; if the number-average molecular weight of the carbomer is too large, the melt strength of high-density polyethylene is too large, which is not conducive to the formation of bubbles, resulting in a decrease in the foaming degree of the foamed polyethylene.

[0036] In some embodiments, the melt flow rate of the high-density polyethylene at 190 °C and 21.6 kg is 1 - 60 g / 10 min, and can be, for example, but not limited to, 1 g / 10 min, 3 g / 10 min, 5 g / 10 min, 10 g / 10 min, 20 g / 10 min, 30 g / 10 min, 40 g / 10 min, 50 g / 10 min, preferably 8 - 20 g / 10 min; the testing standard is GB / T3682.2 - 2018.

[0037] In the present invention, when the melt flow rate of high-density polyethylene at 190 °C and 21.6 kg is 1-60 g / 10 min, the foaming effect is better. When the melt flow rate of high-density polyethylene at 190 °C and 21.6 kg is 3-20 g / 10 min, the foaming degree and tensile strength of foamed polyethylene can be further improved. If the melt flow rate of high-density polyethylene is too low, the melt strength of high-density polyethylene is high. Combining with the thickening effect of carbomer, it is difficult to form pores, resulting in a decrease in the foaming degree of foamed polyethylene. If the melt flow rate of high-density polyethylene is too high, the thickening effect of carbomer cannot meet the formation of bubbles by high-density polyethylene, resulting in a decrease in the foaming degree of foamed polyethylene.

[0038] In the present invention, based on the total mass of the foamed polyethylene composite being 100%, the mass percentage content of high-density polyethylene is not less than 80%.

[0039] In some embodiments, the processing aids include at least one of antioxidants, nucleating agents, antistatic agents, lubricants, plasticizers, release agents, and pigments.

[0040] In some embodiments, the lubricant is at least one of low molecular weight ester lubricants, metal soap lubricants, stearic acid composite ester lubricants, and amide lubricants.

[0041] In the present invention, the lubricant can improve the dispersibility of carbomer, and at the same time reduce the friction between the material and the inside of the extruder during extrusion processing, effectively preventing the premature decomposition of carbomer.

[0042] Specific examples of the lubricant that can be cited are fatty acid amide TR451, zinc stearate, and calcium stearate.

[0043] In some embodiments, the antioxidant is at least one of hindered phenol antioxidants, hindered amine antioxidants, phosphite antioxidants, and thioester antioxidants.

[0044] Specific examples of the antioxidant that can be cited are antioxidant 1010, antioxidant 1076, antioxidant 3114, antioxidant 168, antioxidant PEP-36, and antioxidant 412S.

[0045] The production method of the foamed polyethylene composite material of the present invention is not particularly strictly limited and is carried out using a blending device such as a kneader, a single-screw or twin-screw extruder. The addition order of the components is not particularly strictly limited, and they can be added simultaneously or in a certain order. Two or more components can be selected from all the components for preliminary mixing or kneading. For example, carbomer can be preformed into a masterbatch and then added to the melt of other components in the form of the masterbatch according to a set ratio for extrusion. Under the condition that the mixing capacity of the equipment permits, when molding or producing parts, the particles formed by the masterbatch and other components can also be mixed and melt-processed according to a set ratio. The resin used in the masterbatch can be the high-density polyethylene resin described in the present invention.

[0046] Specifically, the preparation method of the foamed polyethylene composite material includes the following steps:

[0047] Mix high-density polyethylene, carbomer and processing aids evenly in proportion, and then add 0.5-2 parts by weight of a chemical blowing agent and mix evenly to obtain a premix.

[0048] Add the premix into a screw extruder for melt extrusion granulation to obtain a foamed polyethylene composite material.

[0049] In some embodiments, the chemical blowing agent includes an azo blowing agent and / or a carbonate blowing agent;

[0050] Specifically, the azo blowing agent is at least one of azodicarbonamide, 2,2'-azobisisobutyronitrile, diisopropyl azodicarboxylate, and diethyl azodicarboxylate.

[0051] Specifically, the carbonate blowing agent is at least one of sodium bicarbonate, calcium carbonate, and magnesium carbonate.

[0052] Preferably, the chemical blowing agent is bicarbonate. Carbon dioxide is generated by the reaction of bicarbonate and carbomer, and the foaming effect of the foamed polyethylene composite material is good. Moreover, the inventors unexpectedly found that selecting a bicarbonate blowing agent can further increase the melt strength and improve the tensile strength of the foamed polyethylene composite material.

[0053] In some embodiments, the rotation speed of the mixing is 500-700 r / min and the time is 5-10 min.

[0054] In some embodiments, when melt extrusion granulation is carried out, the temperatures of each section of the twin-screw extruder are as follows: the temperature of the first zone is 180°C - 200°C, the temperatures of the second to fourth zones are 190°C - 210°C, the temperatures of the fifth to tenth zones are 180°C - 200°C, and the rotation speed of the screw extruder is 300 rpm - 500 rpm.

[0055] Thirdly, an application of the foamed polyethylene composite material in preparing automotive parts is provided.

[0056] Fourthly, an automotive part is provided, including the foamed polyethylene composite material, and the automotive part is, for example, an automotive air duct, a car door, a roof lining, etc.

[0057] The raw materials used in the examples and comparative examples are described as follows, but are not limited to these materials:

[0058] High-density polyethylene 1: The melt flow rate at 190 °C and 2.16 kg is 1.02 g / 10 min, HDPE5000S, Lanzhou Petrochemical;

[0059] High-density polyethylene 2: The melt flow rate at 190 °C and 2.16 kg is 8.2 g / 10 min, HDPEHSGC7260, Guangdong Petrochemical;

[0060] High-density polyethylene 3: The melt flow rate at 190 °C and 2.16 kg is 13 g / 10 min, HDPE2909, Nova Chemicals;

[0061] High-density polyethylene 4: The melt flow rate at 190 °C and 2.16 kg is 20 g / 10 min, HDPEFMA016, ExxonMobil;

[0062] High-density polyethylene 5: The melt flow rate at 190 °C and 2.16 kg is 50 g / 10 min, HDPE IP 51, Dow Chemical;

[0063] Low-density polyethylene: The melt flow rate at 190 °C and 2.16 kg is 20 g / 10 min, LLDPE M2320 (DNDA-7144); Sinopec;

[0064] Carbomer 1: Cross-linked by pentaerythritol and acrylic acid, the number-average molecular weight is 910,000, Carbomer 940, Xi'an Lavya Biotechnology;

[0065] Carbomer 2: Cross-linked by pentaerythritol and acrylic acid, the number-average molecular weight is 1,230,000, Carbomer 941, Xi'an Lavya Biotechnology;

[0066] Carbomer 3: Cross-linked by pentaerythritol and acrylic acid, the number-average molecular weight is 1,570,000, Carbomer U20, Lubrizol;

[0067] Carbomer 4: Cross-linked by pentaerythritol and acrylic acid, the number-average molecular weight is 1,940,000, Carbomer 974, Lubrizol;

[0068] Carbomer 5: Crosslinked by pentaerythritol and acrylic acid, with a number-average molecular weight of 3.32 million, Carbomer 980, Lubrizol, USA;

[0069] Ethylene / propylene copolymer: Density: 0.88 g / cm 3 , OCPT612, Shengda, Jinzhou;

[0070] Lubricant: Fatty acid amide, TR451, Zhuangjing, Shanghai;

[0071] Antioxidant: A mixture of a hindered phenol antioxidant and a phosphite antioxidant in a mass ratio of 1:1. The hindered phenol antioxidant is SONOX 1010, Sanfeng Chemical Industry; the phosphite antioxidant is SONOX 168, Sanfeng Chemical Industry.

[0072] Examples and comparative examples

[0073] The components and weight parts of the foamed polyethylene composites in the examples and comparative examples are selected as shown in Table 1 and Table 2. Among them, the preparation method of the foamed polyethylene composites in the examples and comparative examples includes the following steps:

[0074] Add each component into a high-speed mixer according to Table 1, and mix at a speed of 600 rpm for 8 min to obtain a premix;

[0075] Add the premix into a twin-screw extruder for melt extrusion granulation to obtain a foamed polyethylene composite; among them, when melt extrusion granulation is carried out, the set temperatures of the twin-screw extruder from the feed port to the head are as follows: the temperature of zone 1 is 180 °C, and the temperatures of zones 2 to 4 are 190 °C, and the temperatures of zones 5 to 10 are 190 °C; the screw speed is 300 rpm, and the length-diameter ratio of the twin-screw extruder is 40:1.

[0076] Table 1

[0077]

[0078] Performance testing

[0079] Perform performance testing on the foamed polyethylene composites obtained in the examples and comparative examples. The testing methods are as follows:

[0080] (1) Tensile strength: Test according to standard ISO 527-2-2019;

[0081] (2) Specific gravity: Test according to ISO 1183-1-2019 standard;

[0082] (3) Foaming degree: (1 - specific gravity 1 / specific gravity 2) × 100%, where specific gravity 1 is the specific gravity of the obtained foamed polyethylene composite, and specific gravity 2 is the specific gravity of the high-density polyethylene used for specific gravity 1.

[0083] The test results are shown in Table 2.

[0084] Table 2

[0085] Tensile strength (MPa) <![CDATA[Specific gravity (g / cm 3 )]]> Degree of foaming (%) Example 1 18.5 0.85 11.5 Example 2 19.5 0.81 15.6 Example 3 21.6 0.77 18.9 Example 4 18.9 0.83 12.5 Example 5 18.3 0.91 5.2 Example 6 18.2 0.93 3.1 Example 7 18.8 0.87 9.4 Example 8 19.1 0.86 10.4 Example 9 18.4 0.94 2.1 Example 10 18.1 0.88 8.3 Example 11 18.2 0.91 4.4 Example 12 16.1 0.88 8.3 Comparative Example 1 22.4 0.96 1.1 Comparative Example 2 17.3 0.96 1.2 Comparative Example 3 21.7 0.93 0.9

[0086] From the experimental data in Table 2, it can be seen that the tensile strength of the foamed polyethylene composite material of the present disclosure is ≥16 MPa, and the highest foaming degree can reach 18.9%, indicating that the foamed polyethylene of the present invention has good foaming degree and tensile strength.

[0087] Comparing Examples 1-5, it can be seen that when the melt flow rate of high-density polyethylene is 8-20 g / 10 min at 190 °C and 2.16 kg, the tensile strength of the obtained foamed polyethylene composite material is ≥18.9 MPa, and the foaming degree is ≥12.5%, indicating that when the melt flow rate of high-density polyethylene is 8-20 g / 10 min at 190 °C and 2.16 kg, the foamed polyethylene composite material has higher tensile strength and foaming degree.

[0088] Comparing Example 3 with Examples 6-9, it can be seen that when the number average molecular weight of carbomer is 1.2-2 million, the tensile strength of the obtained foamed polyethylene composite material is ≥18.8 MPa, and the foaming degree is ≥9.4%, indicating that when the number average molecular weight of carbomer is 1.2-2 million, the foamed polyethylene composite material has higher tensile strength and foaming degree.

[0089] Comparing Example 3 with Comparative Examples 1-3, it can be seen that too little addition of carbomer, or too much addition of carbomer, or replacing carbomer with ethylene / propylene copolymer will result in a decrease in the foaming degree or tensile strength of the foamed polyethylene composite material.

[0090] Figure 1 is a scanning electron microscope image of the cross-section of the foamed polyethylene composite material obtained in Example 1. From Figure 1 it can be seen that the foamed polyethylene composite material of the present invention contains uniformly sized pores and the pores are dense.

[0091] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present disclosure rather than to limit the protection scope of the present disclosure. Although the present disclosure has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present disclosure can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present disclosure.

Claims

1. A foamed polyethylene composite material, characterized in that: The invention comprises the following components in parts by weight: 92-100 parts of high-density polyethylene, 1-5 parts of carbomer and 0.4-2 parts of a processing aid.

2. The foamed polyethylene composite material according to claim 1, characterized in that: The number average molecular weight of the carbomer is 700,000-4,000,000.

3. The foamed polyethylene composite material according to claim 1, characterized in that: The high-density polyethylene has a melt flow rate of 1-60 g / 10 min at 190° C. and 2.16 kg.

4. The foamed polyethylene composite material according to claim 1, characterized in that: The processing aid is a lubricant and / or an antioxidant.

5. The foamed polyethylene composite material according to claim 4, characterized in that: The lubricant is at least one of a low molecular weight ester lubricant, a metal soap lubricant, a stearic acid complex ester lubricant and an amide lubricant.

6. The foamed polyethylene composite material according to claim 4, characterized in that: The antioxidant is at least one of a hindered phenol antioxidant, a hindered amine antioxidant, a phosphite antioxidant and a thioester antioxidant.

7. A method for preparing the foamed polyethylene composite material according to any one of claims 1 to 6, characterized in that: The following steps are involved: High-density polyethylene, carbomer and a processing aid are mixed uniformly according to a certain proportion, and then 0.5-2 parts by weight of a chemical foaming agent are added and mixed uniformly to obtain a premix; The premix is ​​added into a screw extruder for melt extrusion and granulation to obtain a foamed polyethylene composite material.

8. The method for preparing the foamed polyethylene composite material according to claim 7, characterized in that: The chemical foaming agent includes an azo foaming agent and / or a carbonate foaming agent.

9. Use of the foamed polyethylene composite material according to any one of claims 1 to 6 in the preparation of automobile parts.

10. An automobile component, comprising the foamed polyethylene composite material according to any one of claims 1 to 6.

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