Polypropylene microcellular foaming injection molding material and preparation method thereof

Abstract

The invention belongs to the field of high polymer materials, and particularly relates to a polypropylene microcellular foaming injection molding material and a preparation method thereof. The polypropylene microcellular foaming injection molding material provided by the invention is prepared by carrying out microcellular injection foaming molding on a resin master batch; the resin master batch comprises the following components in parts by weight: 20-35 parts of polypropylene random copolymer, 5-10 parts of polypropylene block copolymer, 5-10 parts of polypropylene with high melt strength, 10-20 parts of carbon fibers, 5-10 parts of a toughening agent, 10-20 parts of a flame retardant with a structure as shown in a formula (I), 0.1-1 part of a nucleating agent and 1-5 parts of a floating fiber modifier. According to the invention, the component formula of the polypropylene material is systematically optimized and adjusted, and a microporous injection molding process is combined, so that the polypropylene microporous foaming injection molding material with high strength, high toughness, high flame retardance and light weight is finally prepared, and is very suitable for being used as a new energy automobile battery cover plate material. Formula (I).

Description

Technical Field

[0001] This invention belongs to the field of polymer materials, and particularly relates to a polypropylene microporous foam injection molding material and its preparation method. Background Technology

[0002] With increasing global emphasis on environmental protection and sustainable development, the new energy vehicle market continues to expand rapidly, showing a strong growth trend.

[0003] Against the backdrop of increasingly stringent global carbon emission regulations, the new energy vehicle industry has entered a new stage of development characterized by "electrification as the foundation, intelligence as the soul, low carbon as the responsibility, and ecological sustainability as an extension." Vehicle lightweighting, as an effective means of reducing carbon emissions, aligns perfectly with the environmental protection philosophy of new energy vehicles. The battery cover, as a key protective component of the electric vehicle's power battery, is an indispensable safety structure with the rise of new energy vehicles, and its lightweighting is primarily achieved through material optimization. Currently, battery casings are mostly made of aluminum or steel, while composite material solutions can reduce weight by approximately 40%, becoming a viable lightweighting path.

[0004] Among automotive plastics, polypropylene (PP) has become the most widely used and fastest-growing plastic in the automotive field due to its low density, high cost-effectiveness, excellent heat resistance, rigidity, chemical corrosion resistance, and ease of processing, molding, and recycling. Automotive PP injection-molded parts constitute a major part of the demand for automotive plastics, including battery box covers. These applications require materials with excellent high and low temperature impact toughness, rigidity, heat resistance, and aging resistance. While traditional metal battery covers (such as steel and aluminum plates) are commonly used, they are heavy, detrimental to energy conservation and environmental protection, and prone to corrosion. Therefore, lightweight, high-strength, and high-toughness modified polypropylene battery covers are gradually gaining popularity and showing significant market value. How to further improve the overall performance of modified polypropylene battery covers is a research hotspot in this field. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a polypropylene microporous foam injection molding material and its preparation method. The polypropylene microporous foam injection molding material provided by the present invention has high strength, high toughness, high flame retardancy and light weight.

[0006] This invention provides a polypropylene microporous foam injection molding material, which is made by microporous injection foaming of resin masterbatch; the resin masterbatch comprises, by weight parts:

[0007] 20-35 parts of random copolymer polypropylene;

[0008] 5-10 parts of block copolymer polypropylene;

[0009] 5-10 parts of high melt strength polypropylene;

[0010] 10-20 parts carbon fiber;

[0011] 5-10 parts toughening agent;

[0012] 10-20 parts flame retardant;

[0013] Nucleating agent 0.1~1 part;

[0014] 1-5 parts of fiber float modifier;

[0015] The chemical structure of the flame retardant is shown in formula (I):

[0016] Formula (I).

[0017] Preferably, the melt index of the random copolymer polypropylene at a temperature of 230°C and a load of 2.16 kg is 20~25 g / min; the weight-average molecular weight of the random copolymer polypropylene is 300,000~350,000 g / mol; and the polydispersity index of the random copolymer polypropylene is 2.8~3.2.

[0018] Preferably, the melt index of the block copolymer polypropylene at a temperature of 230°C and a load of 2.16 kg is 1.5~2 g / min; the weight-average molecular weight of the block copolymer polypropylene is 200,000~300,000 g / mol; and the polydispersity index of the block copolymer polypropylene is 3.2~4.

[0019] Preferably, the high melt strength polypropylene has a melt index of 3.6~4.2 g / min under the conditions of 230℃ and 2.16 kg load; the weight-average molecular weight of the high melt strength polypropylene is 150,000~200,000 g / mol; and the polydispersity index of the high melt strength polypropylene is 4.2~4.8.

[0020] Preferably, the carbon fiber has a fiber length of 4-8 mm and a fiber diameter of 1-3 mm.

[0021] Preferably, the toughening agent is saline resin.

[0022] Preferably, the nucleating agent is calcium oxalate.

[0023] Preferably, the resin masterbatch further includes one or more of wetting agents, antioxidants, color masterbatches, and setting agents.

[0024] This invention provides a method for preparing the polypropylene microporous foamed injection molding material described in the above technical solution, comprising the following steps:

[0025] The resin masterbatch is subjected to microporous injection molding to obtain polypropylene microporous foam injection molding material.

[0026] Preferably, the amount of supercritical fluid used in the microporous injection foaming process is 0.25 to 1% of the mass of the resin masterbatch.

[0027] Compared with existing technologies, this invention provides a polypropylene microporous foam injection molding material and its preparation method. The polypropylene microporous foam injection molding material provided by this invention is made from a resin masterbatch through microporous injection molding. By weight, the resin masterbatch comprises: 20-35 parts random copolymer polypropylene, 5-10 parts block copolymer polypropylene, 5-10 parts high melt strength polypropylene, 10-20 parts carbon fiber, 5-10 parts toughening agent, 10-20 parts flame retardant, 0.1-1 parts nucleating agent, and 1-5 parts fiber float modifier. The chemical structure of the flame retardant is shown in formula (I). This invention systematically optimizes and adjusts the composition of the polypropylene material and, combined with the microporous injection molding process, ultimately prepares a polypropylene microporous foam injection molding material with high strength, high toughness, high flame retardancy, and light weight, making it very suitable for use as a battery cover material for new energy vehicles. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0029] Figure 1 This is a synthesis route diagram of the flame retardant provided in the embodiments of the present invention;

[0030] Figure 2 This is an infrared spectrum provided in an embodiment of the present invention. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] This invention provides a polypropylene microporous foam injection molding material, which is made by microporous injection foaming of resin masterbatch; the resin masterbatch comprises, by weight parts:

[0033] 20-35 parts of random copolymer polypropylene;

[0034] 5-10 parts of block copolymer polypropylene;

[0035] 5-10 parts of high melt strength polypropylene;

[0036] 10-20 parts carbon fiber;

[0037] 5-10 parts toughening agent;

[0038] 10-20 parts flame retardant;

[0039] Nucleating agent 0.1~1 part;

[0040] 1-5 parts of fiber-retaining modifier.

[0041] In the polypropylene microporous foam injection molding material provided by this invention, the melt index of the random copolymer polypropylene (PPR) under the conditions of 230℃ and 2.16kg load is preferably 20~25g / min, specifically 20g / min, 20.5g / min, 21g / min, 21.5g / min, 22g / min, 22.5g / min, 23g / min, 23.5g / min, 24g / min, 24.5g / min or 25g / min; the weight-average molecular weight of the random copolymer polypropylene is preferably 300,000~350,000g / mol, specifically... The polydispersity index of the random copolymer polypropylene is preferably 2.8 to 3.2, specifically 2.8, 2.85, 2.9, 2.95, 3, 3, 3.05, 3.1, 3.15, or 3.2. In some specific embodiments of this invention, the random copolymer polypropylene is selected from SABICRA12 random copolymer polypropylene manufactured by Saudi Basic Industries Corporation.

[0042] In the polypropylene microporous foam injection molding material provided by the present invention, the random copolymer polypropylene, especially the above-mentioned specific type of random copolymer polypropylene, reduces the regularity of the macromolecular chain and shortens the isotactic sequence length due to the random insertion of comonomers, thereby possessing good creep resistance and high melt index, meeting the requirements of injection molding process.

[0043] In the polypropylene microporous foam injection molding material provided by the present invention, the content of the random copolymer polypropylene in the resin masterbatch can specifically be 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, or 35 parts by weight.

[0044] In the polypropylene microporous foam injection molding material provided by this invention, the melt index of the block copolymer polypropylene (PPB) under the conditions of 230°C and 2.16kg load is preferably 1.5~2g / min, specifically 1.5g / min, 1.55g / min, 1.6g / min, 1.65g / min, 1.7g / min, 1.75g / min, 1.8g / min, 1.85g / min, 1.9g / min, 1.95g / min or 2g / min; the weight-average molecular weight of the block copolymer polypropylene is preferably 200,000~300,000g / mol, specifically 200,000g / mol, 2100 The polydispersity index of the block copolymer polypropylene is preferably 3.2 to 4, specifically 3.2, 3.25, 3.3, 3.35, 3.4, 3.45, 3.5, 3.55, 3.6, 3.65, 3.68, 3.7, 3.75, 3.8, 3.85, 3.9, 3.95 or 4. In some specific embodiments provided by the present invention, the block copolymer polypropylene is selected from the block copolymer polypropylene (ethylene-propylene block copolymer polypropylene) of model J340 produced by Yangzi Petrochemical.

[0045] In the polypropylene microporous foam injection molding material provided by the present invention, the block copolymer polypropylene, especially the block copolymer polypropylene of the above-mentioned specific type, has a wide operating temperature range and excellent mechanical properties. Its introduction can significantly improve the impact strength of the composite system, especially the impact resistance at low temperatures.

[0046] In the polypropylene microporous foam injection molding material provided by the present invention, the content of the block copolymer polypropylene in the resin masterbatch can be 5 parts by weight, 5.5 parts by weight, 6 parts by weight, 6.5 parts by weight, 7 parts by weight, 7.5 parts by weight, 8 parts by weight, 8.5 parts by weight, 9 parts by weight, 9.5 parts by weight, or 10 parts by weight.

[0047] In the polypropylene microporous foam injection molding material provided by this invention, the melt index of the high melt strength polypropylene (HMSPP) under the conditions of 230°C and 2.16 kg load is preferably 3.6~4.2 g / min, specifically 3.6 g / min, 3.65 g / min, 3.7 g / min, 3.75 g / min, 3.8 g / min, 3.85 g / min, 3.9 g / min, 3.95 g / min, 4 g / min, 4.05 g / min, 4.1 g / min, 4.15 g / min, or 4.2 g / min; the weight-average molecular weight of the high melt strength polypropylene is preferably 150,000~200,000 g / mol. Specifically, the polydispersity index (PDI) can be 150,000 g / mol, 155,000 g / mol, 160,000 g / mol, 165,000 g / mol, 170,000 g / mol, 175,000 g / mol, 180,000 g / mol, 185,000 g / mol, 187,700 g / mol, 190,000 g / mol, 195,000 g / mol, or 200,000 g / mol; the PDI of the high melt strength polypropylene is preferably 4.2 to 4.8, specifically 4.2, 4.25, 4.3, 4.35, 4.4, 4.45, 4.5, 4.56, 4.6, 4.65, 4.7, 4.75, or 4.8. In some specific embodiments provided by this invention, the high melt strength polypropylene is selected from Borealis' WB140 high melt strength polypropylene.

[0048] In the polypropylene microcellular foam injection molding material provided by the present invention, the high melt strength polypropylene, especially the above-mentioned specific type of high melt strength polypropylene, has the characteristics of high melt strength and high impact strength, and also exhibits high tensile strength and high flexural modulus. In addition, it is also conducive to the implementation of microcellular foam injection molding process.

[0049] In the polypropylene microporous foam injection molding material provided by the present invention, the content of high melt strength polypropylene in the resin masterbatch can be 5 parts by weight, 5.5 parts by weight, 6 parts by weight, 6.5 parts by weight, 7 parts by weight, 7.5 parts by weight, 8 parts by weight, 8.5 parts by weight, 9 parts by weight, 9.5 parts by weight, or 10 parts by weight.

[0050] In the polypropylene microporous foam injection molding material provided by this invention, the fiber length of the carbon fiber is preferably 4-8 mm, specifically 4 mm, 4.2 mm, 4.5 mm, 4.7 mm, 5 mm, 5.2 mm, 5.5 mm, 5.7 mm, 6 mm, 6.2 mm, 6.5 mm, 6.7 mm, 7 mm, 7.2 mm, 7.5 mm, 7.7 mm, or 8 mm; the fiber diameter of the carbon fiber is preferably 1-3 mm, specifically 1 mm, 1.2 mm, 1.5 mm, 1.7 mm, 2 mm, 2.3 mm, 2.5 mm, 2.7 mm, or 3 mm. In some specific embodiments provided by this invention, the carbon fiber is selected from the ACECA-6SP2 carbon fiber produced by Shanghai Yutong Chemical Technology Co., Ltd.

[0051] In the polypropylene microporous foam injection molding material provided by this invention, the carbon fiber, especially the aforementioned specific type of carbon fiber, can significantly improve the tensile strength and tensile modulus of the composite material. While ensuring structural rigidity, its low-density characteristics further reduce the weight of the product. Furthermore, the introduction of carbon fiber also helps improve the thermal conductivity of the material, thereby obtaining a lightweight, highly thermally conductive, and comprehensively high-performance polypropylene composite material.

[0052] In the polypropylene microporous foam injection molding material provided by the present invention, the content of carbon fiber in the resin masterbatch can be 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, or 20 parts by weight.

[0053] In the polypropylene microporous foam injection molding material provided by the present invention, the toughening agent is preferably saline resin. In some specific embodiments provided by the present invention, the saline resin is selected from saline resin of model 9910 manufactured by Dow Chemical Company.

[0054] In the polypropylene microporous foam injection molding material provided by the present invention, the sarin resin, especially the sarin resin of the above-mentioned specific type, has excellent low-temperature impact resistance, wear and scratch resistance and high melt strength, which can effectively improve the overall toughness of the composite material.

[0055] In the polypropylene microporous foam injection molding material provided by the present invention, the content of the toughening agent in the resin masterbatch can be 5 parts by weight, 5.5 parts by weight, 6 parts by weight, 6.5 parts by weight, 7 parts by weight, 7.5 parts by weight, 8 parts by weight, 8.5 parts by weight, 9 parts by weight, 9.5 parts by weight, or 10 parts by weight.

[0056] In the polypropylene microporous foam injection molding material provided by the present invention, the chemical structure of the flame retardant is shown in formula (I):

[0057] Formula (I).

[0058] In the polypropylene microporous foam injection molding material provided by the present invention, the flame retardant of the formula (I) structure is an organophosphorus flame retardant (DT) synthesized by reacting 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) with 1,3,5-triallyl cyanurate (TAC). This flame retardant is prepared by the addition reaction of PH bond and C=C bond, combining the meltability of DOPO derivatives with the excellent thermal stability of triazine ring. It not only has a high flame retardant effect, but also has good heat resistance and compatibility with polyolefin matrix, thereby significantly improving the safety and reliability of composite materials.

[0059] In the polypropylene microporous foam injection molding material provided by the present invention, the flame retardant content in the resin masterbatch can specifically be 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, or 20 parts by weight.

[0060] In the polypropylene microporous foam injection molding material provided by the present invention, the nucleating agent is preferably calcium oxalate.

[0061] In the polypropylene microporous foam injection molding material provided by the present invention, the nucleating agent, especially the above-mentioned specific type of nucleating agent, can promote crystallization, reduce molding cycle, and promote cell nucleation.

[0062] In the polypropylene microporous foam injection molding material provided by the present invention, the nucleating agent in the resin masterbatch may specifically be 0.1 parts by weight, 0.2 parts by weight, 0.3 parts by weight, 0.4 parts by weight, 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight, or 1 part by weight.

[0063] In the polypropylene microporous foamed injection molding material provided by the present invention, the floating fiber modifier can specifically be the floating fiber modifier with model number CYD-MP05 produced by Weihai Chenyuan Molecular New Materials Co., Ltd.

[0064] In the polypropylene microporous foam injection molding material provided by the present invention, the fiber floating modifier, especially the above-mentioned specific type of fiber floating modifier, can improve melt flowability, effectively suppress common problems such as surface fiber floating and warping deformation during fiber-added injection molding, and improve the appearance quality and dimensional stability of the product.

[0065] In the polypropylene microporous foam injection molding material provided by the present invention, the content of the floating fiber modifier in the resin masterbatch can be 1 part by weight, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight, or 5 parts by weight.

[0066] In the polypropylene microporous foam injection molding material provided by the present invention, the resin masterbatch preferably further includes one or more of the following: a wetting agent, an antioxidant, a color masterbatch, and a setting agent. Specifically, the wetting agent can be ExxonMobil's A80 wetting agent; the antioxidant is preferably antioxidant 168 and / or antioxidant 1010; the color masterbatch is preferably a black masterbatch, specifically Zhejiang Jiahua Fine Chemicals Co., Ltd.'s SC-6500 black masterbatch; and the setting agent can be Shanghai Mohe New Material Technology Co., Ltd.'s 886 setting agent.

[0067] In the polypropylene microporous foam injection molding material provided by the present invention, the content of the wetting agent in the resin masterbatch is preferably 1 to 5 parts by weight, specifically 1 part by weight, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight or 5 parts by weight.

[0068] In the polypropylene microporous foam injection molding material provided by the present invention, the antioxidant content in the resin masterbatch is preferably 1 to 5 parts by weight, specifically 1 part by weight, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight or 5 parts by weight.

[0069] In the polypropylene microporous foam injection molding material provided by the present invention, the content of the color masterbatch in the resin masterbatch is preferably 1 to 5 parts by weight, specifically 1 part by weight, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight or 5 parts by weight.

[0070] In the polypropylene microporous foam injection molding material provided by the present invention, the content of the sizing agent in the resin masterbatch is preferably 0.1 to 1 part by weight, specifically 0.1 part by weight, 0.2 part by weight, 0.3 part by weight, 0.4 part by weight, 0.5 part by weight, 0.6 part by weight, 0.7 part by weight, 0.8 part by weight, 0.9 part by weight or 1 part by weight.

[0071] The present invention also provides a method for preparing the polypropylene microporous foam injection molding material described in the above technical solution, comprising the following steps:

[0072] The resin masterbatch is subjected to microporous injection molding to obtain polypropylene microporous foam injection molding material.

[0073] In the preparation method provided by the present invention, the resin masterbatch is preferably prepared according to the following steps: the raw materials of the resin masterbatch are melt-blended and then extruded and granulated to obtain the resin masterbatch. Preferably, the raw materials are pre-mixed uniformly before melt blending; the melt blending is preferably carried out in an extruder, more preferably in a twin-screw extruder; the operating temperature of the extruder is preferably 180~200℃; and the screw speed of the extruder is preferably 100~200 rpm.

[0074] In the preparation method provided by the present invention, the microporous injection foaming is carried out in a microporous injection foaming equipment; wherein, the barrel temperature of the microporous injection foaming equipment is preferably 210~230℃; and the mold temperature of the microporous injection foaming equipment is preferably 220~240℃.

[0075] In the preparation method provided by the present invention, the supercritical fluid injected during the microporous injection molding foaming process is preferably N2; the amount of supercritical fluid used in the microporous injection molding foaming process is preferably 0.25~1% of the mass of the resin masterbatch, specifically 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95% or 1%.

[0076] The technical solution provided by this invention optimizes the composition and formulation of polypropylene materials and combines it with microporous injection molding technology to obtain a polypropylene microporous foam injection molded material with high strength, high toughness, high flame retardancy, and light weight. This material exhibits excellent overall performance and is highly suitable for use as a battery cover material for new energy vehicles. More specifically, the technical solution of this invention includes the following key points and advantages:

[0077] (1) Random copolymer polypropylene has good creep resistance and high melt index, which ensures the excellent processing adaptability of the material. Block copolymer polypropylene can significantly broaden the service temperature range of the material and improve the low temperature impact resistance. High melt strength polypropylene, on the basis of giving the system high tensile strength, high flexural modulus and high impact strength, its unique foaming adaptability also provides key support for the implementation of microporous foaming injection molding process. The synergistic combination of the three polypropylenes enables the matrix material to achieve comprehensive optimization in terms of processability, mechanical properties and foaming process adaptability.

[0078] (2) Sarin resin toughening agent has excellent low-temperature impact resistance, wear and scratch resistance and high melt strength, which can effectively improve the overall toughness of polypropylene composite materials.

[0079] (3) Carbon fiber can significantly improve the tensile strength and tensile modulus of composite materials. While ensuring the structural rigidity, it can further reduce the weight of the product by utilizing its low density characteristics. In addition, the introduction of carbon fiber can also help improve the thermal conductivity of the material, thereby obtaining a lightweight, highly thermally conductive and excellent polypropylene composite material.

[0080] (4) In terms of flame retardant systems, an organophosphorus flame retardant (DT) based on the reaction of phosphaphenanthrene (DOPO) and triallyl 1,3,5-cyanurate (TAC) was developed. This flame retardant was prepared by the addition reaction of PH bond and C=C bond, combining the meltability of DOPO derivatives with the excellent thermal stability of triazine ring. It not only has a high flame retardant effect, but also has good heat resistance and compatibility with polyolefin matrix, thereby significantly improving the safety and reliability of composite materials.

[0081] (5) To further optimize the material processing and foaming performance, calcium oxalate, a nucleating agent, was introduced to reduce the energy barrier for bubble formation, accelerate the foaming speed, and regulate the size and distribution of the pores to obtain a uniform and fine pore structure.

[0082] (6) By adding a fiber-adding modifier to improve melt flowability, the main problem of fiber dispersion, fiber exposure and fiber floating in PP fiber-adding system can be solved. It can effectively suppress common problems such as surface fiber floating and warping deformation in fiber-adding injection molding process, and improve the appearance quality and dimensional stability of the product.

[0083] (7) The microporous injection foaming process is used to replace the traditional injection molding technology, forming a uniform microporous structure inside the material, thereby further realizing the effective weight reduction of the product.

[0084] In summary, the technical solution of this invention, through the combination of multi-component synergistic design and microporous foaming process, successfully prepared a high-performance, lightweight polypropylene composite material that can meet the usage requirements of battery box covers for new energy vehicles.

[0085] For clarity, the following examples and comparative models will be used to provide a detailed description.

[0086] In the following embodiments and comparative examples provided by this invention, the flame retardant used is a self-made organophosphorus flame retardant (DT), and its synthesis route is as follows: Figure 1 As shown, the specific synthesis process is as follows:

[0087] First, 67.0 g of phosphaphenanthrene (DOPO) and 50 mL of toluene were added to a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser. The mixture was then heated to 90 °C until the DOPO was completely dissolved. Next, 25 g of 2,4,6-triallyl-1,3,5-triazine (TAC) was dissolved in 30 mL of toluene and then added dropwise to the reaction system over 0.5 h using a constant-pressure dropping funnel. After that, 1.0 g of dicumyl peroxide (DCP) was dissolved in 1 mL of toluene and added dropwise to the reaction system in three portions using a syringe. Finally, the reaction system was heated to 110 °C and reacted for 20 h with continuous mechanical stirring. After the reaction was completed, the toluene solvent in the system was removed by vacuum distillation, and the solid was dried under vacuum to obtain a light yellow solid.

[0088] The infrared spectra of the raw materials 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and 1,3,5-triallyl cyanurate (TAC), and the resulting organophosphorus flame retardant (DT) are as follows: Figure 2 As shown.

[0089] In the following embodiments and comparative examples provided by this invention, the information on other raw materials used besides flame retardants is as follows:

[0090] Random copolymer polypropylene: model SABIC RA12, Saudi Basic Industries Corporation, melt index 23.0 g / min (230℃, 2.16 kg), weight average molecular weight 322700 g / mol, PDI=3.05;

[0091] Block copolymer polypropylene: Model J340, Yangzi Petrochemical, melt index 1.7 g / min (230℃, 2.16 kg), weight average molecular weight 260600 g / mol, PDI=3.68;

[0092] High melt strength polypropylene: model WB140, Borealis, melt index 3.9 g / min (230℃, 2.16 kg), weight average molecular weight 187700 g / mol, PDI=4.56;

[0093] Toughening agent: Salin resin, model 9910, Dow Chemical Company;

[0094] Carbon fiber: Model ACECA-6SP2, Shanghai Yutong Chemical Technology Co., Ltd., fiber length 6mm, fiber diameter 2mm;

[0095] Nucleating agent: calcium oxalate, model C804541, Shanghai Maclean Biochemical Technology Co., Ltd.;

[0096] Wetting agent: Model A80, ExxonMobil;

[0097] Antioxidants: Models 168 and 1010, BASF;

[0098] Fiber Float Modifier: Model CYD-MP05, Weihai Chenyuan Molecular New Materials Co., Ltd.;

[0099] Black masterbatch: Model SC-6500, Zhejiang Jiahua Fine Chemicals Co., Ltd.;

[0100] Fixative: Model 886, Shanghai Mohe New Materials Technology Co., Ltd.

[0101] Example 1

[0102] (1) Ingredient design (parts by weight):

[0103] 30 parts random copolymer polypropylene, 5 parts block copolymer polypropylene, 10 parts high melt strength polypropylene, 5 parts toughening agent, 20 parts carbon fiber, 20 parts flame retardant, 0.5 parts nucleating agent, 2 parts wetting agent, 2 parts antioxidant (1010:168=1:2, mass ratio), 3 parts floating fiber modifier, 2 parts black masterbatch, and 0.5 parts setting agent.

[0104] (2) Preparation of resin masterbatch:

[0105] Random copolymer polypropylene, block copolymer polypropylene, high melt strength polypropylene, carbon fiber, toughening agent, flame retardant, nucleating agent, antioxidant, wetting agent, fiber floating modifier, sizing agent and black masterbatch are mechanically blended according to the formula ratio, and then melt blended and extruded granulated through a twin-screw extruder to obtain polypropylene microporous foam injection molding special resin masterbatch.

[0106] The settings for the twin-screw extruder are as follows:

[0107] Zone 1: 180~190℃, Zone 2: 190~195℃, Zone 3: 190~195℃, Zone 4: 190~195℃, Zone 5: 195~200℃, Zone 6: 195~200℃, Zone 7: 195~200℃, Zone 8: 195~200℃, Die head: 195~200℃; Screw speed: 100~200rpm.

[0108] (3) Preparation of polypropylene microporous foam injection molded products:

[0109] The obtained polypropylene microporous foam injection molding special resin masterbatch is injection molded using microporous foam injection molding equipment to finally obtain high-performance polypropylene microporous foam injection molded products.

[0110] Among them, the MuCell® microcellular foaming injection molding equipment from KraussMaffei was used to injection mold the polypropylene microcellular foaming injection molding special resin masterbatch.

[0111] The barrel temperature of the microporous foaming injection molding equipment is set as follows:

[0112] Zone 1: 210~220℃, Zone 2: 220~230℃, Zone 3: 220~230℃, Zone 4: 220~230℃, Zone 5: 220~230℃, Zone 6: 220~230℃, Zone 7: 220~230℃, Zone 8: 220~230℃, Zone 9: 220~230℃, Zone 10: 220~230℃, Zone 11: 220~230℃, Zone 12: 220~230℃.

[0113] The mold temperature setting of the microporous foaming injection molding equipment is:

[0114] Zone 1: 220~230℃, Zone 2: 220~230℃, Zone 3: 220~230℃, Zone 4: 230~235℃, Zone 5: 230~235℃, Zone 6: 230~235℃, Zone 7: 230~240℃, Zone 8: 230~240℃, Zone 9: 230~240℃, Zone 10: 230~240℃, Zone 11: 230~240℃, Zone 12: 230~240℃, Zone 13: 230~240℃, Zone 14: 230~240℃, Zone 15: 230~240℃, Zone 16: 230~240℃, Zone 17: 230~240℃, Zone 18: 230~240℃, Zone 19: 230~240℃, Zone 20: 230~240℃, Zone 21: 230~240℃, Zone 22: 230~240℃, Zone 23: 230~240℃, Zone 24: 230~240℃, Zone 25: 230~240℃, Zone 26: 230~240℃, Zone 27: 230~240℃, Zone 28: 230~240℃, Zone 29: 230~240℃, Zone 30: 230~240℃, Zone 31: 230~240℃, Zone 32: 230~240℃, Zone 33: 230~240℃, Zone 34: 230~240℃.

[0115] The amount of supercritical fluid (SCF) used in the microporous foaming injection molding equipment is 1% of the mass of the injection molding material.

[0116] Parameters of the supercritical fluid nitrogen injection controller:

[0117] Level 1: Pressure (target pressure value) 140 bar (supercritical, because it is much higher than the critical pressure of 33.9 bar for N2), Time (duration of stage) 5.0 s, Speed ​​(pressure change rate) 600 bar / s (pressure rises very quickly, rapid pressure increase stage).

[0118] Level 2: Pressure 180 bar, time 9.0 s, speed 600 bar / s (maintain high pressure, filling for a longer time).

[0119] Level 3: Pressure 150 bar, time 5.0 s, speed 300 bar / s (pressure slightly reduced, filling speed decreased);

[0120] Level 4: Pressure 0.0 bar, Time 2.0 s, Speed ​​300 bar / s (Decompression phase, rapid pressure reduction);

[0121] Start-up delay: 1.9s (nitrogen gas starts 1.9 seconds after injection begins);

[0122] Number of control levels: 4 levels of parameter control.

[0123] Example 2

[0124] (1) Ingredient design (parts by weight):

[0125] 20 parts random copolymer polypropylene, 10 parts block copolymer polypropylene, 10 parts high melt strength polypropylene, 10 parts toughening agent, 20 parts carbon fiber, 20 parts flame retardant, 0.5 parts nucleating agent, 2 parts wetting agent, 2 parts antioxidant (1010:168=1:2, mass ratio), 3 parts floating fiber modifier, 2 parts black masterbatch, and 0.5 parts setting agent.

[0126] (2) Preparation of resin masterbatch:

[0127] Random copolymer polypropylene, block copolymer polypropylene, high melt strength polypropylene, carbon fiber, toughening agent, flame retardant, nucleating agent, antioxidant, wetting agent, fiber floating modifier, sizing agent and black masterbatch are mechanically blended according to the formula ratio, and then melt blended and extruded granulated through a twin-screw extruder to obtain polypropylene microporous foam injection molding special resin masterbatch.

[0128] The settings for the twin-screw extruder are as follows:

[0129] Zone 1: 180~190℃, Zone 2: 190~195℃, Zone 3: 190~195℃, Zone 4: 190~195℃, Zone 5: 195~200℃, Zone 6: 195~200℃, Zone 7: 195~200℃, Zone 8: 195~200℃, Die head: 195~200℃; Screw speed: 100~200rpm.

[0130] (3) Preparation of polypropylene microporous foam injection molded products:

[0131] The obtained polypropylene microporous foam injection molding special resin masterbatch is injection molded using microporous foam injection molding equipment to finally obtain high-performance polypropylene microporous foam injection molded products.

[0132] Among them, the MuCell® microcellular foaming injection molding equipment from KraussMaffei was used to injection mold the polypropylene microcellular foaming injection molding special resin masterbatch.

[0133] The barrel temperature of the microporous foaming injection molding equipment is set as follows:

[0134] Zone 1: 210~220℃, Zone 2: 220~230℃, Zone 3: 220~230℃, Zone 4: 220~230℃, Zone 5: 220~230℃, Zone 6: 220~230℃, Zone 7: 220~230℃, Zone 8: 220~230℃, Zone 9: 220~230℃, Zone 10: 220~230℃, Zone 11: 220~230℃, Zone 12: 220~230℃.

[0135] The mold temperature setting of the microporous foaming injection molding equipment is:

[0136] Zone 1: 220~230℃, Zone 2: 220~230℃, Zone 3: 220~230℃, Zone 4: 230~235℃, Zone 5: 230~235℃, Zone 6: 230~235℃, Zone 7: 230~240℃, Zone 8: 230~240℃, Zone 9: 230~240℃, Zone 10: 230~240℃, Zone 11: 230~240℃, Zone 12: 230~240℃, Zone 13: 230~240℃, Zone 14: 230~240℃, Zone 15: 230~240℃, Zone 16: 230~240℃, Zone 17: 230~240℃, Zone 18: 230~240℃, Zone 19: 230~240℃, Zone 20: 230~240℃, Zone 21: 230~240℃, Zone 22: 230~240℃, Zone 23: 230~240℃, Zone 24: 230~240℃, Zone 25: 230~240℃, Zone 26: 230~240℃, Zone 27: 230~240℃, Zone 28: 230~240℃, Zone 29: 230~240℃, Zone 30: 230~240℃, Zone 31: 230~240℃, Zone 32: 230~240℃, Zone 33: 230~240℃, Zone 34: 230~240℃.

[0137] The amount of supercritical fluid (SCF) used in the microporous foaming injection molding equipment is 1% of the mass of the injection molding material.

[0138] Parameters of the supercritical fluid nitrogen injection controller:

[0139] Level 1: Pressure (target pressure value) 140 bar (supercritical, because it is much higher than the critical pressure of 33.9 bar for N2), Time (duration of stage) 5.0 s, Speed ​​(pressure change rate) 600 bar / s (pressure rises very quickly, rapid pressure increase stage).

[0140] Level 2: Pressure 180 bar, time 9.0 s, speed 600 bar / s (maintain high pressure, filling for a longer time).

[0141] Level 3: Pressure 150 bar, time 5.0 s, speed 300 bar / s (pressure slightly reduced, filling speed decreased);

[0142] Level 4: Pressure 0.0 bar, Time 2.0 s, Speed ​​300 bar / s (Decompression phase, rapid pressure reduction);

[0143] Start-up delay: 1.9s (nitrogen gas starts 1.9 seconds after injection begins);

[0144] Number of control levels: 4 levels of parameter control.

[0145] Example 3

[0146] (1) Ingredient design (parts by weight):

[0147] 35 parts random copolymer polypropylene, 5 parts block copolymer polypropylene, 5 parts high melt strength polypropylene, 5 parts toughening agent, 20 parts carbon fiber, 20 parts flame retardant, 0.5 parts nucleating agent, 2 parts wetting agent, 2 parts antioxidant (1010:168=1:2, mass ratio), 3 parts floating fiber modifier, 2 parts black masterbatch, and 0.5 parts setting agent.

[0148] Random copolymer polypropylene, block copolymer polypropylene, high melt strength polypropylene, carbon fiber, toughening agent, flame retardant, nucleating agent, antioxidant, wetting agent, fiber floating modifier, sizing agent and black masterbatch are mechanically blended according to the formula ratio, and then melt blended and extruded granulated through a twin-screw extruder to obtain polypropylene microporous foam injection molding special resin masterbatch.

[0149] The settings for the twin-screw extruder are as follows:

[0150] Zone 1: 180~190℃, Zone 2: 190~195℃, Zone 3: 190~195℃, Zone 4: 190~195℃, Zone 5: 195~200℃, Zone 6: 195~200℃, Zone 7: 195~200℃, Zone 8: 195~200℃, Die head: 195~200℃; Screw speed: 100~200rpm.

[0151] (3) Preparation of polypropylene microporous foam injection molded products:

[0152] The obtained polypropylene microporous foam injection molding special resin masterbatch is injection molded using microporous foam injection molding equipment to finally obtain high-performance polypropylene microporous foam injection molded products.

[0153] Among them, the MuCell® microcellular foaming injection molding equipment from KraussMaffei was used to injection mold the polypropylene microcellular foaming injection molding special resin masterbatch.

[0154] The barrel temperature of the microporous foaming injection molding equipment is set as follows:

[0155] Zone 1: 210~220℃, Zone 2: 220~230℃, Zone 3: 220~230℃, Zone 4: 220~230℃, Zone 5: 220~230℃, Zone 6: 220~230℃, Zone 7: 220~230℃, Zone 8: 220~230℃, Zone 9: 220~230℃, Zone 10: 220~230℃, Zone 11: 220~230℃, Zone 12: 220~230℃.

[0156] The mold temperature setting of the microporous foaming injection molding equipment is:

[0157] Zone 1: 220~230℃, Zone 2: 220~230℃, Zone 3: 220~230℃, Zone 4: 230~235℃, Zone 5: 230~235℃, Zone 6: 230~235℃, Zone 7: 230~240℃, Zone 8: 230~240℃, Zone 9: 230~240℃, Zone 10: 230~240℃, Zone 11: 230~240℃, Zone 12: 230~240℃, Zone 13: 230~240℃, Zone 14: 230~240℃, Zone 15: 230~240℃, Zone 16: 230~240℃, Zone 17: 230~240℃, Zone 18: 230~240℃, Zone 19: 230~240℃, Zone 20: 230~240℃, Zone 21: 230~240℃, Zone 22: 230~240℃, Zone 23: 230~240℃, Zone 24: 230~240℃, Zone 25: 230~240℃, Zone 26: 230~240℃, Zone 27: 230~240℃, Zone 28: 230~240℃, Zone 29: 230~240℃, Zone 30: 230~240℃, Zone 31: 230~240℃, Zone 32: 230~240℃, Zone 33: 230~240℃, Zone 34: 230~240℃.

[0158] The amount of supercritical fluid (SCF) used in the microporous foaming injection molding equipment is 1% of the mass of the injection molding material.

[0159] Parameters of the supercritical fluid nitrogen injection controller:

[0160] Level 1: Pressure (target pressure value) 140 bar (supercritical, because it is much higher than the critical pressure of 33.9 bar for N2), Time (duration of stage) 5.0 s, Speed ​​(pressure change rate) 600 bar / s (pressure rises very quickly, rapid pressure increase stage).

[0161] Level 2: Pressure 180 bar, time 9.0 s, speed 600 bar / s (maintain high pressure, filling for a longer time).

[0162] Level 3: Pressure 150 bar, time 5.0 s, speed 300 bar / s (pressure slightly reduced, filling speed decreased);

[0163] Level 4: Pressure 0.0 bar, Time 2.0 s, Speed ​​300 bar / s (Decompression phase, rapid pressure reduction);

[0164] Start-up delay: 1.9s (nitrogen gas starts 1.9 seconds after injection begins);

[0165] Number of control levels: 4 levels of parameter control.

[0166] Comparative Example 1

[0167] (1) Ingredient design (parts by weight):

[0168] 40 parts random copolymer polypropylene, 5 parts block copolymer polypropylene, 5 parts toughening agent, 20 parts carbon fiber, 20 parts flame retardant, 0.5 parts nucleating agent, 2 parts wetting agent, 2 parts antioxidant (1010:168=1:2, mass ratio) 2 parts floating fiber modifier, 2 parts black masterbatch, and 0.5 parts setting agent.

[0169] Random copolymer polypropylene, block copolymer polypropylene, carbon fiber, toughening agent, flame retardant, nucleating agent, antioxidant, wetting agent, fiber floating modifier, sizing agent and black masterbatch are mechanically blended according to the formula ratio, and then melt-blended and extruded granulated through a twin-screw extruder to obtain polypropylene microporous foam injection molding special resin masterbatch.

[0170] The settings for the twin-screw extruder are as follows:

[0171] Zone 1: 180~190℃, Zone 2: 190~195℃, Zone 3: 190~195℃, Zone 4: 190~195℃, Zone 5: 195~200℃, Zone 6: 195~200℃, Zone 7: 195~200℃, Zone 8: 195~200℃, Die head: 195~200℃; Screw speed: 100~200rpm.

[0172] (3) Preparation of polypropylene microporous foam injection molded products:

[0173] The obtained polypropylene microporous foam injection molding special resin masterbatch is injection molded using microporous foam injection molding equipment to finally obtain high-performance polypropylene microporous foam injection molded products.

[0174] Among them, the MuCell® microcellular foaming injection molding equipment from KraussMaffei was used to injection mold the polypropylene microcellular foaming injection molding special resin masterbatch.

[0175] The barrel temperature of the microporous foaming injection molding equipment is set as follows:

[0176] Zone 1: 210~220℃, Zone 2: 220~230℃, Zone 3: 220~230℃, Zone 4: 220~230℃, Zone 5: 220~230℃, Zone 6: 220~230℃, Zone 7: 220~230℃, Zone 8: 220~230℃, Zone 9: 220~230℃, Zone 10: 220~230℃, Zone 11: 220~230℃, Zone 12: 220~230℃.

[0177] The mold temperature setting of the microporous foaming injection molding equipment is:

[0178] Zone 1: 220~230℃, Zone 2: 220~230℃, Zone 3: 220~230℃, Zone 4: 230~235℃, Zone 5: 230~235℃, Zone 6: 230~235℃, Zone 7: 230~240℃, Zone 8: 230~240℃, Zone 9: 230~240℃, Zone 10: 230~240℃, Zone 11: 230~240℃, Zone 12: 230~240℃, Zone 13: 230~240℃, Zone 14: 230~240℃, Zone 15: 230~240℃, Zone 16: 230~240℃, Zone 17: 230~240℃, Zone 18: 230~240℃, Zone 19: 230~240℃, Zone 20: 230~240℃, Zone 21: 230~240℃, Zone 22: 230~240℃, Zone 23: 230~240℃, Zone 24: 230~240℃, Zone 25: 230~240℃, Zone 26: 230~240℃, Zone 27: 230~240℃, Zone 28: 230~240℃, Zone 29: 230~240℃, Zone 30: 230~240℃, Zone 31: 230~240℃, Zone 32: 230~240℃, Zone 33: 230~240℃, Zone 34: 230~240℃.

[0179] The amount of supercritical fluid (SCF) used in the microporous foaming injection molding equipment is 1% of the mass of the injection molding material.

[0180] Parameters of the supercritical fluid nitrogen injection controller:

[0181] Parameters of the supercritical fluid nitrogen injection controller:

[0182] Level 1: Pressure (target pressure value) 140 bar (supercritical, because it is much higher than the critical pressure of 33.9 bar for N2), Time (duration of stage) 5.0 s, Speed ​​(pressure change rate) 600 bar / s (pressure rises very quickly, rapid pressure increase stage).

[0183] Level 2: Pressure 180 bar, time 9.0 s, speed 600 bar / s (maintain high pressure, filling for a longer time).

[0184] Level 3: Pressure 150 bar, time 5.0 s, speed 300 bar / s (pressure slightly reduced, filling speed decreased);

[0185] Level 4: Pressure 0.0 bar, Time 2.0 s, Speed ​​300 bar / s (Decompression phase, rapid pressure reduction);

[0186] Start-up delay: 1.9s (nitrogen gas starts 1.9 seconds after injection begins);

[0187] Number of control levels: 4 levels of parameter control.

[0188] Comparative Example 2

[0189] (1) Ingredient design (parts by weight):

[0190] 40 parts random copolymer polypropylene, 10 parts high melt strength polypropylene, 20 parts carbon fiber, 20 parts flame retardant, 0.5 parts nucleating agent, 2 parts wetting agent, 2 parts antioxidant (1010:168=1:2, mass ratio), 3 parts floating fiber modifier, 2 parts black masterbatch, and 0.5 parts setting agent.

[0191] Random copolymer polypropylene, high melt strength polypropylene, carbon fiber, flame retardant, nucleating agent, antioxidant, wetting agent, fiber floating modifier, sizing agent and black masterbatch are mechanically blended according to the formula ratio, and then melt blended and extruded granulated through a twin-screw extruder to obtain polypropylene microporous foam injection molding special resin masterbatch.

[0192] The settings for the twin-screw extruder are as follows:

[0193] Zone 1: 180~190℃, Zone 2: 190~195℃, Zone 3: 190~195℃, Zone 4: 190~195℃, Zone 5: 195~200℃, Zone 6: 195~200℃, Zone 7: 195~200℃, Zone 8: 195~200℃, Die head: 195~200℃; Screw speed: 100~200rpm.

[0194] (3) Preparation of polypropylene microporous foam injection molded products:

[0195] The obtained polypropylene microporous foam injection molding special resin masterbatch is injection molded using microporous foam injection molding equipment to finally obtain high-performance polypropylene microporous foam injection molded products.

[0196] Among them, the MuCell® microcellular foaming injection molding equipment from KraussMaffei was used to injection mold the polypropylene microcellular foaming injection molding special resin masterbatch.

[0197] The barrel temperature of the microporous foaming injection molding equipment is set as follows:

[0198] Zone 1: 210~220℃, Zone 2: 220~230℃, Zone 3: 220~230℃, Zone 4: 220~230℃, Zone 5: 220~230℃, Zone 6: 220~230℃, Zone 7: 220~230℃, Zone 8: 220~230℃, Zone 9: 220~230℃, Zone 10: 220~230℃, Zone 11: 220~230℃, Zone 12: 220~230℃.

[0199] The mold temperature setting of the microporous foaming injection molding equipment is:

[0200] Zone 1: 220~230℃, Zone 2: 220~230℃, Zone 3: 220~230℃, Zone 4: 230~235℃, Zone 5: 230~235℃, Zone 6: 230~235℃, Zone 7: 230~240℃, Zone 8: 230~240℃, Zone 9: 230~240℃, Zone 10: 230~240℃, Zone 11: 230~240℃, Zone 12: 230~240℃, Zone 13: 230~240℃, Zone 14: 230~240℃, Zone 15: 230~240℃, Zone 16: 230~240℃, Zone 17: 230~240℃, Zone 18: 230~240℃, Zone 19: 230~240℃, Zone 20: 230~240℃, Zone 21: 230~240℃, Zone 22: 230~240℃, Zone 23: 230~240℃, Zone 24: 230~240℃, Zone 25: 230~240℃, Zone 26: 230~240℃, Zone 27: 230~240℃, Zone 28: 230~240℃, Zone 29: 230~240℃, Zone 30: 230~240℃, Zone 31: 230~240℃, Zone 32: 230~240℃, Zone 33: 230~240℃, Zone 34: 230~240℃.

[0201] The amount of supercritical fluid (SCF) used in the microporous foaming injection molding equipment is 1% of the mass of the injection molding material.

[0202] Parameters of the supercritical fluid nitrogen injection controller:

[0203] Level 1: Pressure (target pressure value) 140 bar (supercritical, because it is much higher than the critical pressure of 33.9 bar for N2), Time (duration of stage) 5.0 s, Speed ​​(pressure change rate) 600 bar / s (pressure rises very quickly, rapid pressure increase stage).

[0204] Level 2: Pressure 180 bar, time 9.0 s, speed 600 bar / s (maintain high pressure, filling for a longer time).

[0205] Level 3: Pressure 150 bar, time 5.0 s, speed 300 bar / s (pressure slightly reduced, filling speed decreased);

[0206] Level 4: Pressure 0.0 bar, Time 2.0 s, Speed ​​300 bar / s (Decompression phase, rapid pressure reduction);

[0207] Start-up delay: 1.9s (nitrogen gas starts 1.9 seconds after injection begins);

[0208] Number of control levels: 4 levels of parameter control.

[0209] Comparative Example 3

[0210] (1) Ingredient design (parts by weight):

[0211] 50 parts random copolymer polypropylene, 5 parts block copolymer polypropylene, 10 parts high melt strength polypropylene, 5 parts toughening agent, 20 parts carbon fiber, 0.5 parts nucleating agent, 2 parts wetting agent, 2 parts antioxidant (1010:168=1:2, mass ratio), 3 parts floating fiber modifier, 2 parts black masterbatch, and 0.5 parts setting agent.

[0212] Random copolymer polypropylene, block copolymer polypropylene, high melt strength polypropylene, carbon fiber, toughening agent, nucleating agent, antioxidant, wetting agent, fiber floating modifier, sizing agent and black masterbatch are mechanically blended according to the formula ratio, and then melt blended and extruded granulated through a twin-screw extruder to obtain polypropylene microporous foam injection molding special resin masterbatch.

[0213] The settings for the twin-screw extruder are as follows:

[0214] Zone 1: 180~190℃, Zone 2: 190~195℃, Zone 3: 190~195℃, Zone 4: 190~195℃, Zone 5: 195~200℃, Zone 6: 195~200℃, Zone 7: 195~200℃, Zone 8: 195~200℃, Die head: 195~200℃; Screw speed: 100~200rpm.

[0215] (3) Preparation of polypropylene microporous foam injection molded products:

[0216] The obtained polypropylene microporous foam injection molding special resin masterbatch is injection molded using microporous foam injection molding equipment to finally obtain high-performance polypropylene microporous foam injection molded products.

[0217] Among them, the MuCell® microcellular foaming injection molding equipment from KraussMaffei was used to injection mold the polypropylene microcellular foaming injection molding special resin masterbatch.

[0218] The barrel temperature of the microporous foaming injection molding equipment is set as follows:

[0219] Zone 1: 210~220℃, Zone 2: 220~230℃, Zone 3: 220~230℃, Zone 4: 220~230℃, Zone 5: 220~230℃, Zone 6: 220~230℃, Zone 7: 220~230℃, Zone 8: 220~230℃, Zone 9: 220~230℃, Zone 10: 220~230℃, Zone 11: 220~230℃, Zone 12: 220~230℃.

[0220] The mold temperature setting of the microporous foaming injection molding equipment is:

[0221] Zone 1: 220~230℃, Zone 2: 220~230℃, Zone 3: 220~230℃, Zone 4: 230~235℃, Zone 5: 230~235℃, Zone 6: 230~235℃, Zone 7: 230~240℃, Zone 8: 230~240℃, Zone 9: 230~240℃, Zone 10: 230~240℃, Zone 11: 230~240℃, Zone 12: 230~240℃, Zone 13: 230~240℃, Zone 14: 230~240℃, Zone 15: 230~240℃, Zone 16: 230~240℃, Zone 17: 230~240℃, Zone 18: 230~240℃, Zone 19: 230~240℃, Zone 20: 230~240℃, Zone 21: 230~240℃, Zone 22: 230~240℃, Zone 23: 230~240℃, Zone 24: 230~240℃, Zone 25: 230~240℃, Zone 26: 230~240℃, Zone 27: 230~240℃, Zone 28: 230~240℃, Zone 29: 230~240℃, Zone 30: 230~240℃, Zone 31: 230~240℃, Zone 32: 230~240℃, Zone 33: 230~240℃, Zone 34: 230~240℃.

[0222] The amount of supercritical fluid (SCF) used in the microporous foaming injection molding equipment is 1% of the mass of the injection molding material.

[0223] Parameters of the supercritical fluid nitrogen injection controller:

[0224] Level 1: Pressure (target pressure value) 140 bar (supercritical, because it is much higher than the critical pressure of 33.9 bar for N2), Time (duration of stage) 5.0 s, Speed ​​(pressure change rate) 600 bar / s (pressure rises very quickly, rapid pressure increase stage).

[0225] Level 2: Pressure 180 bar, time 9.0 s, speed 600 bar / s (maintain high pressure, filling for a longer time).

[0226] Level 3: Pressure 150 bar, time 5.0 s, speed 300 bar / s (pressure slightly reduced, filling speed decreased);

[0227] Level 4: Pressure 0.0 bar, Time 2.0 s, Speed ​​300 bar / s (Decompression phase, rapid pressure reduction);

[0228] Start-up delay: 1.9s (nitrogen gas starts 1.9 seconds after injection begins);

[0229] Number of control levels: 4 levels of parameter control.

[0230] Performance Evaluation

[0231] The performance of the polypropylene microporous foamed injection molded products prepared in Examples 1-3 and Comparative Examples 1-3 was tested, and the results are shown in Table 1:

[0232] Table 1 Performance test results of polypropylene microcellular foam injection molded products

[0233]

[0234] The following conclusions can be drawn from Table 1: Compared with Example 1, the melt index of Example 2 decreased and the impact strength increased; compared with Example 1, the melt index of Example 3 increased, the tensile strength increased, and the impact strength decreased; compared with Example 1, Comparative Example 1 did not contain polypropylene (WB140), and the melt index of the composite material increased, which means that the melt strength of the composite material deteriorated; compared with Example 1, Comparative Example 2 did not contain polypropylene (J340) and toughening agent (9910), and the impact strength of the composite material decreased; compared with Example 1, Comparative Example 3 did not contain flame retardant, and the composite material did not have flame retardant function.

[0235] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A polypropylene microporous foam injection molding material, characterized in that, It is made by microporous injection molding of resin masterbatch; by weight, the resin masterbatch comprises: 20-35 parts of random copolymer polypropylene; 5-10 parts of block copolymer polypropylene; 5-10 parts of high melt strength polypropylene; 10-20 parts carbon fiber; 5-10 parts toughening agent; 10-20 parts flame retardant; Nucleating agent 0.1~1 part; 1-5 parts of fiber float modifier; The chemical structure of the flame retardant is shown in formula (I): Equation (I).

2. The polypropylene microporous foam injection molding material according to claim 1, characterized in that, The random copolymer polypropylene has a melt index of 20~25 g / min under the conditions of 230℃ and 2.16 kg load; the weight average molecular weight of the random copolymer polypropylene is 300,000~350,000 g / mol; and the polydispersity index of the random copolymer polypropylene is 2.8~3.

2.

3. The polypropylene microporous foam injection molding material according to claim 1, characterized in that, The block copolymer polypropylene has a melt index of 1.5~2 g / min at a temperature of 230℃ and a load of 2.16 kg; the weight-average molecular weight of the block copolymer polypropylene is 200,000~300,000 g / mol; and the polydispersity index of the block copolymer polypropylene is 3.2~4.

4. The polypropylene microporous foam injection molding material according to claim 1, characterized in that, The high melt strength polypropylene has a melt index of 3.6~4.2 g / min under the conditions of 230℃ and 2.16 kg load; the weight average molecular weight of the high melt strength polypropylene is 150,000~200,000 g / mol; and the polydispersity index of the high melt strength polypropylene is 4.2~4.

8.

5. The polypropylene microporous foam injection molding material according to claim 1, characterized in that, The carbon fiber has a fiber length of 4-8 mm and a fiber diameter of 1-3 mm.

6. The polypropylene microporous foam injection molding material according to claim 1, characterized in that, The toughening agent is saline resin.

7. The polypropylene microporous foam injection molding material according to claim 1, characterized in that, The nucleating agent is calcium oxalate.

8. The polypropylene microporous foam injection molding material according to claim 1, characterized in that, The resin masterbatch also includes one or more of the following: wetting agent, antioxidant, color masterbatch, and setting agent.

9. A method for preparing a polypropylene microporous foamed injection molding material according to any one of claims 1 to 8, characterized in that, Includes the following steps: The resin masterbatch is subjected to microporous injection molding to obtain polypropylene microporous foam injection molding material.

10. The preparation method according to claim 9, characterized in that, The amount of supercritical fluid used in the microporous injection foaming process is 0.25~1% of the mass of the resin masterbatch.

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