Polypropylene composite material as well as preparation method and application thereof

Abstract

The invention provides a polypropylene composite material as well as a preparation method and application thereof. The polypropylene composite material comprises the following components: 64.9 wt%-94.97 wt% of a polypropylene resin base material, 5 wt%-30 wt% of LLDPE (Linear Low Density Polyethylene) and 0.03 wt%-0.1 wt% of a nucleating agent. The invention also provides a preparation method of the polypropylene composite material. According to the polypropylene composite material provided by the invention, all the raw material components are reasonably combined and proportioned, so that the problem that the impact performance and transparency of polypropylene cannot be synchronously improved is solved, and the high-impact-resistance and high-transparency polypropylene composite material with excellent performance can be obtained. The preparation method of the high-impact-resistance and high-transparency polypropylene composite material provided by the invention is simple and easy to implement, is suitable for large-scale production in various molding factories, is suitable for packaging foods, medicines and daily necessities, can replace PET or PC, and has a wide market prospect in the fields of packaging materials and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of polymer modified plastics, and particularly relates to a polypropylene composite material and a preparation method and application thereof. BACKGROUND

[0002] Polypropylene resin has good heat resistance, processing performance and mechanical strength, and also has low density, easy recycling, recyclable and other characteristics, and is widely used in the fields of automobiles, electrical appliances, daily necessities, home furnishing and packaging. Transparent polypropylene is widely used in food packaging, medical products, media product packaging, finishing boxes, beverage bottles, milk bottles and the like due to its transparent and aesthetic appearance, good hygiene and heat resistance. Since the early 1980s, transparent polypropylene has rapidly developed worldwide due to its many advantages. In recent years, the consumption of transparent polypropylene in China has also increased rapidly, and the annual demand for transparent polypropylene in China in 2020 was about 2 million tons.

[0003] Traditional transparent polypropylene is usually obtained by adding a transparent agent to homopolymer or random copolymer polypropylene. However, there is a prominent problem in the use that the impact performance of the product is poor at low temperature, and it cannot meet the requirements of the refrigerator cold drawer when subjected to impact force. The impact resistance of impact copolymer polypropylene is greatly improved due to the introduction of rubber phase in the polypropylene matrix, but the transparency of the product is poor due to the large size of the rubber phase, and the haze is generally about 60%, which cannot meet the requirements of transparency in many fields.

[0004] In the case of both requiring transparency and high impact resistance, the current method is to blend random polypropylene with POP, POE, SEBS and other elastomers, which can improve the impact resistance of the product to some extent. However, on the other hand, this method requires secondary processing, increasing the cost of the product, and the increase of the elastomer increases the haze of the product.

[0005] CN106554448A discloses a high-impact transparent polypropylene, which is prepared by controlling the gas phase reaction process parameters to prepare an ethylene propylene copolymer with an ethylene content of 4.0-8.0wt%, wherein 1-3wt% participates in the random copolymerization of ethylene propylene to form random copolymer polypropylene, and 3-5wt% participates in the block copolymerization of ethylene propylene to form impact copolymer polypropylene. The prepared product has good transparent impact comprehensive performance by adding transparent agent and other additives, but the random copolymer polypropylene and impact copolymer polypropylene formed therein are generated in the gas phase reactor. In order to simultaneously consider the transparency of the product, the normal temperature impact performance is good, but the low temperature (-20℃) impact performance is only 1.2-1.5kJ / m 2 .

[0006] CN107880402A discloses a high transparent high impact polypropylene resin suitable for blow molding process, a random copolymer of propylene and ethylene with ethylene content of 3-5wt%, melt flow rate of 0.1-2.0g / 10min, and additives transparent nucleating agent, halogen absorber, antioxidant are mixed and extruded to obtain a transparent impact product with good transparency, high low temperature impact performance, suitable for preparing hollow blow molded products and sheet and sheet for vacuum forming, but the melt flow rate of the prepared transparent impact product is low, the low temperature impact performance is still low, and the requirement of higher low temperature impact performance of daily necessities cannot be met.

[0007] Therefore, how to provide a high impact high transparent polypropylene composite material with good transparency, high low temperature impact performance, suitable for preparing hollow blow molded products and sheet and sheet for vacuum forming is a technical problem to be solved at present. SUMMARY

[0008] In order to solve the above technical problems, the purpose of the present application is to provide a high impact high transparent polypropylene composite material and its preparation method and application. The polypropylene composite material has the characteristics of good transparency (especially low haze) and high low temperature impact performance, and is suitable for preparing high impact high transparent polypropylene composite products of hollow blow molded products and sheet and sheet for vacuum forming.

[0009] The first aspect of the present application is to provide a polypropylene composite material, comprising the following components:

[0010] Polypropylene resin base 64.9wt%-94.97wt%

[0011] LLDPE 5wt%-35wt%

[0012] Nucleating agent 0.03wt%-0.1wt%

[0013] The LLDPE is an ultra-low density LLDPE copolymerized by at least three monomers.

[0014] The present application uses an ultra-low density LLDPE copolymerized by at least three monomers, under the above specific ratio and combination conditions, it is unexpectedly found that the influence on the polypropylene composite material is not only better to improve the toughness, but also the biggest discovery is that the influence on the haze of polypropylene is greatly reduced, which is significantly better than the influence of conventional binary ultra-low density LLDPE on polypropylene.

[0015] According to the present application, preferably, the total mass of the polypropylene resin base, the nucleating agent and the quaternary copolymer ultra-low density LLDPE is 100wt%.

[0016] According to some preferred embodiments of the present application, the polypropylene resin base has a melt index of 0.5-75 g / 10 min at 230°C under a load of 2.16 kg.

[0017] According to some preferred embodiments of the present application, the polypropylene resin base is one of a homopolymer polypropylene or a random copolymer polypropylene.

[0018] More preferably, the homopolymer polypropylene has a crystallinity of more than 40%, and / or an isotacticity of more than 98%, and / or a molecular weight distribution coefficient Mw / Mn of 4-12; an isotacticity of more than 97.5%; and a wide molecular weight distribution Mw / Mn of 4-7.

[0019] More preferably, the random copolymer polypropylene has a comonomer of ethylene or / and butene; more preferably, the repeat unit mass content of the ethylene or / and butene monomer is 0.5-5 wt%; and / or, the random copolymer polypropylene has a molecular weight distribution coefficient Mw / Mn of 4-12.

[0020] According to the present application, the crystallinity of the polypropylene is calculated using the ratio of the melt enthalpy of the raw material to the melt enthalpy when the polypropylene is 100% crystallized; and the isotacticity of the polypropylene is determined using the ratio of the absorbance of the infrared spectrum characteristic absorption peak of the polypropylene to the absorbance of the infrared spectrum characteristic absorption peak of the isotactic polypropylene.

[0021] According to some preferred embodiments of the present application, the ultra-low density LLDPE is selected from a terpolymer ultra-low density LLDPE and / or a tetrapolymer ultra-low density LLDPE.

[0022] The ultra-low density LLDPE is selected from a terpolymer ultra-low density LLDPE and / or a tetrapolymer ultra-low density LLDPE.

[0023] According to some preferred embodiments of the present application, preferably, the ultra-low density LLDPE is a terpolymer ultra-low density LLDPE, more preferably, the terpolymer ultra-low density LLDPE has the following characteristics: the comonomer is butene and hexene, the repeat unit mass content of the hexene and butene monomer is 2-7%; the melt index is 0.5-3.0 g / 10 min at 190°C under a load of 2.16 kg; and the density is 0.905-0.910 g / cm 3 .

[0024] According to some preferred embodiments of the present application, preferably, the ultra-low density LLDPE is a tetra-copolymer ultra-low density LLDPE, more preferably, the tetra-copolymer ultra-low density LLDPE has the following characteristics: the comonomers are butene, hexene and octene, the mass content of the repeating units of butene, hexene and octene monomers is 3-10 wt%, and the melt index at 190°C under 2.16 kg is 0.5-3 g / 10 min, and the density is 0.905-0.910 g / cm 3 .

[0025] According to some preferred embodiments of the present application, the nucleating agent is 1,3:2,4-bis(3,4-dimethyl) benzyl sorbitol, preferably Irgaclear XT 386.

[0026] According to some preferred embodiments of the present application, the polypropylene composite material comprises the following components:

[0027] polypropylene resin base 64.9 wt% to 88.93 wt%,

[0028] LLDPE 11 wt% to 35 wt%,

[0029] nucleating agent 0.07 wt% to 0.1 wt%;

[0030] More preferably, the following components are included:

[0031] polypropylene resin base 64.9 wt% to 79.94 wt%,

[0032] LLDPE 20 wt% to 35 wt%,

[0033] nucleating agent 0.06 wt% to 0.1 wt%.

[0034] The second aspect of the present application is to provide a preparation method of the polypropylene composite material of the first aspect, comprising the following steps: mixing, melt-extruding the polypropylene resin base, LLDPE and nucleating agent according to the mass ratio, to obtain the polypropylene composite material.

[0035] According to some preferred embodiments of the present application, after melt-extruding, the steps of drawing, cooling, granulating, and drying treatment are further included.

[0036] According to some preferred embodiments of the present application, the mixing conditions include: low speed 0-600 r / min, preferably 400-600 r / min, mixing for 1-3 minutes, and then high speed 800-2000 r / min mixing for 1-2 minutes.

[0037] According to some preferred embodiments of the present application, the melt extrusion is performed in a twin-screw extruder; preferably, the rotation speed of the twin-screw extruder is 100-600 r / min, and / or the temperature from feeding to the head is set to be 190-200℃, 195-205℃, 200-210℃, 205-215℃, 205-215℃, 200-210℃, 195-205℃, 190-200℃, 185-195℃.

[0038] The third aspect of the present application provides a polypropylene composite product, which is made of the polypropylene composite material according to the first aspect or prepared by the method according to the second aspect.

[0039] Preferably, the polypropylene composite product is a polypropylene composite sheet.

[0040] The polypropylene composite material of the present application has high impact resistance and excellent high transparency, and is particularly suitable for the production of injection-molded, hollow blow-molded products and thermoformed sheets.

[0041] The fourth aspect of the present application provides a method for preparing the polypropylene composite product according to the third aspect, which comprises injection molding, thermoforming or blow molding the polypropylene composite material according to the first aspect or prepared by the method according to the second aspect to obtain the polypropylene composite product.

[0042] The fifth aspect of the present application provides the use of the polypropylene composite material according to the first aspect or prepared by the method according to the second aspect, or the polypropylene composite product according to the third aspect or prepared by the method according to the fourth aspect in the packaging field.

[0043] The present application has the following advantages:

[0044] (1) The high-impact high-transparency polypropylene composite material provided by the present application solves the problem that the impact resistance and transparency of polypropylene cannot be improved simultaneously by reasonably combining and proportioning the components of the raw materials, and can obtain a high-impact high-transparency polypropylene composite material with excellent performance.

[0045] (2) The specific LLDPE (at least three monomers copolymerized ultra-low density LLDPE) selected by the present application can be well mixed with polypropylene when the polymer system is extruded from a twin-screw extruder or an injection molding machine, which can effectively improve the impact resistance of the polypropylene composite material without reducing the transparency of the resin.

[0046] (3) The polypropylene composite material in the application has lower haze, similar toughness performance, and reduced cost compared with the polypropylene composite material containing POE; moreover, the conventional nucleating agent is added in an amount of 0.2% to 0.5% by weight, while the application only needs to add 0.03% to 0.1% by weight of the nucleating agent, greatly reducing the cost.

[0047] (4) The preparation method of the high-impact high-transparency polypropylene composite material provided by the application is simple and easy to implement, is suitable for large-scale production in injection molding, thermoforming and blow molding factories, is suitable for food, medicine and daily necessities packaging, can replace PET or PC, and has a broad market prospect in the field of packaging materials and the like. DETAILED DESCRIPTION

[0048] The application will be described in detail below in combination with specific examples. It is necessary to point out here that the following examples are only used to further illustrate the application and should not be understood as limiting the protection scope of the application. Some non-essential improvements and adjustments to the application made by those skilled in the art based on the content of the application still fall within the protection scope of the application.

[0049] The embodiments of the application will be described in detail below in combination with examples, but those skilled in the art will understand that the following examples are only used to illustrate the application and should not be regarded as limiting the scope of the application. The specific conditions are not specified in the examples, and the conventional conditions or the conditions recommended by the manufacturer are used. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be obtained on the market.

[0050] (I) Raw materials

[0051] The random copolymerized polypropylene PPR-ET02 is a random copolymerized polypropylene produced by Sinopec Tianjin Branch, with a trade name of PPR-ET02, a melt flow rate of 2 g / 10 min (test conditions: 230℃, 2.16 kg), a comonomer of ethylene, an ethylene monomer content of 2.5% by weight, and a molecular weight distribution coefficient Mw / Mn of the random copolymerized polypropylene of 5.4.

[0052] The homopolymerized polypropylene PPH-E03 is a homopolymerized polypropylene produced by Sinopec Tianjin Branch, with a trade name of PPH-E03, a melt flow rate of 3.0 g / 10 min (test conditions: 230℃, 2.16 kg), a molecular weight distribution coefficient Mw / Mn of 5.9, and a crystallinity of the homopolymerized polypropylene of 44.5%, and a isotacticity of 98.5%.

[0053] The nucleating agent is Irgaclear XT 386 produced by BASF Company.

[0054] The tetra-copolymerized ultra-low density LLDPE is F081-8 produced by Tianjin Petrochemical Company, the comonomers are butene, hexene and octene, the mass content of the repeating units of butene, hexene and octene monomers is 8.5wt%; the melt index is 1.0 g / 10 min at 190°C under a load of 2.16 kg; the density is 0.908 g / cm 3 .

[0055] The tri-copolymerized ultra-low density LLDPE is TJVL1210 produced by Tianjin Petrochemical Company, the comonomers are butene and hexene, the mass content of the repeating units of butene and hexene monomers is 8wt%; the melt index is 1.0 g / 10 min at 190°C under a load of 2.16 kg; the density is 0.910 g / cm 3 .

[0056] The toughening agent in Comparative Example 1 is POE, which is an Exxon Mobil product.

[0057] The binary LLDPE in Comparative Example 6 is a general-purpose LLDPE, which is a product of Yangzi Petrochemical Company, the comonomer is butene, the mass content of the repeating units of butene monomers is 7.0wt%; the melt index is 2.0 g / 10 min at 190°C under a load of 2.16 kg; the density is 0.920 g / cm 3 .

[0058] The SEBS in Comparative Example 2 is YH-688 produced by Balin Petrochemical, the melt index is 0.5 g / 10 min at 190°C under a load of 2.16 kg.

[0059] The comparative transparent nucleating agent NA-98 is a product of Guangzhou Chenghe, which is a sorbitol-based polypropylene transparent nucleating agent.

[0060] (ii) Test methods

[0061] Basic mechanical property test: the notched impact strength of a simply supported beam is tested according to the national standard GB / T 1043.1-2008; the haze and light transmittance are tested according to the national standard GB / T 2410-2008.

[0062] Example 1

[0063] The raw material components, the random copolymerized polypropylene PPR-ET02, the tetra-copolymerized ultra-low density LLDPE F081-8 and the nucleating agent Irgaclear XT 386, are weighed according to the weight ratio in Table 1, and are placed in a high-speed mixer, which is first mixed at a low speed of 600 r / min for 2 minutes, and then mixed at a high speed of 2000 r / min for 1 minute.

[0064] The uniformly mixed raw materials are added into the twin-screw extruder from the main feeding port, melt extruded, drawn, cooled, granulated, and then dried to prepare the high-impact high-transparency composite material, wherein the rotating speed of the extruder screw is 100-600 r / min, and the temperature of the extruder from the feeding port to the head is set as 190-200℃, 195-205℃, 200-210℃, 205-215℃, 205-215℃, 200-210℃, 195-205℃, 190-200℃, and 185-195℃.

[0065] Examples 2-9

[0066] Examples 2-9 differ from Example 1 only in the weight ratio of the components, as shown in Table 1.

[0067] Example 10

[0068] The components of the raw materials, i.e., homopolymer polypropylene PPH-E03, tetra-copolymer ultra-low-density LLDPE F081-8, and nucleating agent Irgaclear XT 386, are weighed according to the weight ratio in Table 1 and placed in a high-speed mixer, which is first mixed at a low speed of 600 r / min for 2 minutes and then at a high speed of 2000 r / min for 1 minute.

[0069] The uniformly mixed raw materials are added into the twin-screw extruder from the main feeding port, melt extruded, drawn, cooled, granulated, and then dried to prepare the high-impact high-transparency composite material, wherein the rotating speed of the extruder screw is 100-600 r / min, and the temperature of the extruder from the feeding port to the head is set as 190-200℃, 195-205℃, 200-210℃, 205-215℃, 205-215℃, 200-210℃, 195-205℃, 190-200℃, and 185-195℃.

[0070] Examples 11-18

[0071] Examples 11-18 differ from Example 10 only in the weight ratio of the components; and Example 10 differs from Example 1 in that the random copolymer polypropylene PPR-ET02 is replaced by the homopolymer polypropylene PPH-E03.

[0072] Example 19

[0073] The components of the raw materials, i.e., homopolymer polypropylene PPH-E03, tetra-copolymer ultra-low-density LLDPE F081-8, and nucleating agent Irgaclear XT 386, are weighed according to the weight ratio in Table 1 and placed in a high-speed mixer, which is first mixed at a low speed of 600 r / min for 2 minutes and then at a high speed of 2000 r / min for 1 minute.

[0074] The uniformly mixed raw materials are added into the twin-screw extruder from the main feeding port, and high-impact high-transparency composite materials are prepared after melt extrusion, drawing, cooling, granulation, and drying treatment, wherein the rotation speed of the extruder screw is 100-600 r / min, and the temperature setting of the extruder from the feeding to the head is 190-200℃, 195-205℃, 200-210℃, 205-215℃, 205-215℃, 200-210℃, 195-205℃, 190-200℃, and 185-195℃.

[0075] Examples 20-27

[0076] Examples 20-27 differ from Example 19 only in the weight ratio of the components; Example 19 differs from Example 1 in that the random copolymerized polypropylene PPR-ET02 is replaced by homopolymerized polypropylene PPH-E03, and the tetra-copolymerized ultra-low-density LLDPE F081-8 is replaced by tri-copolymerized ultra-low-density LLDPE TJVL1210.

[0077] Comparative Example 1

[0078] Comparative Example 1 differs from Example 1 in that the raw materials do not contain a toughening agent and a nucleating agent by themselves, POE is added, and the component contents are shown in Table 1.

[0079] Comparative Example 2

[0080] Comparative Example 2 differs from Example 1 in that the raw material is homopolymerized polypropylene PPH-E03, which is the same as in Example 11, does not contain a toughening agent and a nucleating agent by itself, SEBS is added, and the component contents are shown in Table 1.

[0081] Comparative Example 3

[0082] Comparative Example 3 differs from Example 1 in that the raw materials do not contain a toughening agent and a nucleating agent by themselves, and the component contents are shown in Table 1.

[0083] Comparative Example 4

[0084] Comparative Example 4 differs from Example 1 in that a nucleating agent NA-98 is added, and the component contents are shown in Table 1.

[0085] Comparative Example 5

[0086] Comparative Example 5 differs from Example 1 in the component contents, and the specific component contents are shown in Table 1.

[0087] Comparative Example 6

[0088] In Comparative Example 6, LLDPE F081-8 is not used, but ordinary binary LLDPE is used, the component contents are shown in Table 1, and the specific component contents are shown in Table 1.

[0089] The components and contents of the raw materials used in the examples and comparative examples are shown in Table 1. In Table 1, each component in the examples is in mass percent, unless otherwise specified. The properties of the high-impact high-transparency polypropylene composite materials prepared in the examples and comparative examples are shown in Tables 2-4.

[0090] Table 1

[0091]

[0092]

[0093]

[0094] Table 2

[0095]

[0096] Table 3

[0097]

[0098]

[0099] Table 4

[0100]

[0101]

[0102] Table 5

[0103]

[0104]

[0105] In applications, the requirements for the polypropylene composite material are: in terms of toughness: room temperature impact strength ≥ 9 KJ / m 2 ; low temperature impact strength ≥ 1 KJ / m 2 ; in terms of transparency: haze ≤ 25%, light transmittance ≥ 85%; and low cost.

[0106] In the prior art, the toughening method for the polypropylene composite material is usually to add POE; or ordinary LLDPE.

[0107] POE cost is high, the comparative example 1 adopts POE, although the toughening effect of POE is also very good, meanwhile, the influence on haze is smaller, but the cost of POE is very high, but often causes the cost of polypropylene composite material containing POE to increase, the cost of ternary or quaternary copolymerized ultralow density LLDPE is 60% to 30% of POE under the same amount.

[0108] Common binary LLDPE has greater influence on haze, and it is difficult to consider toughness and haze at the same time. It can be seen from the comparison of examples 1-18 and comparative example 2 and comparative example 6 that the haze of the polypropylene composite material of the application is obviously better than that of comparative example 2 and comparative example 6. On this basis, the toughness of the polypropylene composite material of the application can also meet the application requirements, and the toughness of the examples corresponding to the preferred technical solutions is obviously better than that of comparative example 2 and comparative example 6.

[0109] It can be known from the comparison of examples and comparative examples that the impact performance and haze of the polypropylene composite material in the application are obviously better than those of comparative example 2 and comparative example 6, and the toughness performance is similar to that of comparative example 1, but the cost is reduced. It can be seen that the polypropylene composite material provided by the application has lower haze, which can effectively improve the impact resistance of the polypropylene composite material and does not reduce the transparency of the resin.

[0110] It can be found from the test data of examples and comparative examples in tables 2-4 that after adding the quaternary copolymerized ultralow density LLDPE in the random copolymerized polypropylene, the low-temperature impact resistance (-30℃ Charpy notched impact strength) of the polypropylene composite material can be improved from 1.01KJ / m 2 to 6.9KJ / m 2 ; the normal-temperature impact resistance (23℃ Charpy notched impact strength) can be improved from 9.16KJ / m 2 to 72.9KJ / m 2 . More happily, the haze in example 1-9 is obviously reduced.

[0111] It can be known from the comparison of examples 1-18 and comparative example 4 and comparative example 5 that the polypropylene composite material obtained by using the raw material components in the application under the specific ratio conditions has lower haze and toughness performance meeting the application requirements, and the polypropylene composite material not in the ratio range of the application cannot have the characteristics of low haze and high toughness, and the ratio of the application achieves an unexpected technical effect.

[0112] From the above examples and comparative examples, it can be seen that the auxiliary agent formula system provided by the present application not only has high transparency of polypropylene resin, reduces the haze, but also greatly improves the low-temperature impact resistance of the resin, balances the high transparency and high toughness, and has good effects on homopolymer polypropylene and random copolymer polypropylene.

[0113] The above description of the examples is for the purpose of enabling and providing a general understanding of the present application. Those skilled in the art will readily appreciate that various modifications and adaptations can be made to these examples without departing from the scope of the present application, and that the general principles underlying the present application can be applied to other examples without resort to inventive faculty. Thus, the present application is not intended to be limited to the examples described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. For example, other functional additives can be added to the components of the present application to impart corresponding properties to the composite material.

[0114] It should be noted that the above-described examples are merely intended to explain the present application and do not constitute any limitation on the present application. The present application has been described by referring to typical examples, but it should be understood that the words used therein are descriptive and explanatory words, not limiting words. Modifications can be made to the present application within the scope of the claims of the present application, and the present application can be revised without departing from the scope and spirit of the present application. Although the present application described therein relates to specific methods, materials and examples, it does not mean that the present application is limited to the specific examples disclosed therein, on the contrary, the present application can be extended to all other methods and applications having the same function.

[0115] All publications, patent applications, patents and other references mentioned in this specification are herein incorporated by reference. Unless otherwise defined, all technical and scientific terms used in this specification are intended to have the meanings commonly attributed to them by those of ordinary skill in the art. In case of conflict, the definitions in this specification will control.

[0116] When the specification derives materials, substances, methods, steps, devices or components, etc. with the word head "known to those skilled in the art", "prior art" or similar words, the objects derived by the word head cover those commonly used in the art at the time of filing this application, but also include those which are not commonly used at present, but will be recognized as suitable for similar purposes in the art.

[0117] The endpoints of the ranges and any values disclosed in the specification are not limited to the precise values recited as the exact dimensions are not considered to be critical unless specifically indicated otherwise. The endpoints of the ranges of values are generally intended to be read to be open-ended, and the ranges of values are generally intended to be continuous along at least a portion of the value range unless otherwise indicated. For values which are less than one, multiple, e.g., 10, can be present, such as, e.g., 2, 3, 4, 5, 6, 7, 8, 9, or 10 unless otherwise indicated. The endpoints of the ranges of values will be read to be independently combinable with each other to form new ranges of values unless otherwise indicated or will be read to be mutually exclusive, such as "less than 10" and "greater than 5," unless otherwise indicated. Individual point values, ranges of values and individual ranges of values can be combined with each other to form one or more new ranges of values which should be considered to be specifically disclosed herein. In the following text, individual technical solutions can be combined with each other to form new technical solutions in principle, which should also be considered to be specifically disclosed herein.

[0118] In the context of the present specification, unless specifically indicated otherwise, any matter or item not mentioned is directly applicable without any change to those known in the art.

[0119] Furthermore, any embodiment described herein can be freely combined with one or more other embodiments described herein, and the technical solutions or technical ideas thus formed are considered to be part of the original disclosure or original description of the present application and should not be considered to be new matters which have not been disclosed or anticipated herein, unless the combination is considered to be obviously unreasonable by a person skilled in the art.

Claims

1. A polypropylene composite material comprising the following components: Polypropylene resin base material 64.9wt%~94.97wt% LLDPE 5wt%~35wt% Nucleating agent 0.03wt% to 0.1wt%; The LLDPE is an ultra-low density LLDPE copolymerized from at least three monomers.

2. The polypropylene composite material according to claim 1, characterized in that The melt index of the polypropylene resin base material is 0.5 to 75 g / 10 min at 230° C. and 2.16 kg; and / or The nucleating agent is 1,3:2,4-di(3,4-dimethyl)benzylidene sorbitol.

3. The polypropylene composite material according to claim 1, characterized in that The polypropylene resin base material is one of homopolymer polypropylene or random copolymer polypropylene; Preferably, the homopolypropylene has a crystallinity of more than 40%, and / or an isotacticity greater than 98%, and / or a molecular weight distribution coefficient Mw / Mn=4-12; preferably, the isotacticity is greater than 97.5%; the molecular weight distribution width Mw / Mn=4-7; and / or, Preferably, the comonomer of the random copolymer polypropylene is ethylene and / or butene; more preferably, the mass content of repeating units of ethylene and / or butene monomers is 0.5-5 wt%; and / or the molecular weight distribution coefficient Mw / Mn of the random copolymer polypropylene is 4-12.

4. The polypropylene composite material according to claim 1, wherein The ultra-low density LLDPE is selected from ternary copolymer ultra-low density LLDPE and / or tetrapolymer ultra-low density LLDPE; Preferably, the ultra-low density LLDPE is a ternary copolymer ultra-low density LLDPE, and more preferably, the ternary copolymer ultra-low density LLDPE has the following characteristics: the comonomers are butene and hexene, and the mass content of the repeating units of the hexene and butene monomers is 2-7%; the melt index is 0.5-3.0.g / 10min at 190°C and 2.16kg; and the density is 0.905-0.910g / cm 3 ; Preferably, the ultra-low density LLDPE is a quaternary copolymer ultra-low density LLDPE, and more preferably, the quaternary copolymer ultra-low density LLDPE has the following characteristics: the comonomers are butene, hexene and octene, the mass content of the repeating units of the butene, hexene and octene monomers is 3-10wt%, and the melt index is 0.5-3g / 10min at 190°C and 2.16kg, and the density is 0.905-0.910g / cm 3 .

5. The polypropylene composite material according to any one of claims 1 to 4, characterized in that Includes the following components: Polypropylene resin base material 64.9wt%~88.93wt%, LLDPE 11wt%~35wt%, Nucleating agent 0.07wt% to 0.1wt%; More preferably, the following components are included: Polypropylene resin base material 64.9wt%~79.94wt%, LLDPE 20wt%~35wt%, Nucleating agent 0.06wt%~0.1wt%.

6. A method for preparing the polypropylene composite material according to any one of claims 1 to 5, comprising the following steps: mixing the polypropylene resin base material, LLDPE and a nucleating agent according to a mass ratio, and melt-extruding to obtain a polypropylene composite material; preferably, After melt extrusion, the process also includes strip drawing, cooling, granulation and drying.

7. The preparation method according to claim 6, characterized in that The mixing conditions include: mixing at a low speed of 0-600 r / min, preferably 400-600 r / min, for 1-3 minutes, and then mixing at a high speed of 800-2000 r / min for 1-2 minutes; and / or, The melt extrusion is carried out in a twin-screw extruder; preferably, the rotation speed of the twin-screw extruder is 100-600 r / min, and / or the temperature from feeding to the die is set to: 190℃-200℃, 195℃-205℃, 200℃-210℃, 205℃-215℃, 205-215℃, 200℃-210℃, 195℃-205℃, 190℃-200℃, 185℃-195℃.

8. A polypropylene composite product, wherein the material of the polypropylene composite product is the polypropylene composite material according to any one of claims 1 to 5 or the polypropylene composite material prepared by the preparation method according to any one of claims 6 to 7; Preferably, the polypropylene composite product is a polypropylene composite sheet.

9. A method for preparing the polypropylene composite product according to claim 8, comprising subjecting the polypropylene composite material according to any one of claims 1 to 5 or the polypropylene composite material prepared by the preparation method according to any one of claims 6 to 7 to injection molding, thermoforming or blow molding to obtain the polypropylene composite product.

10. Use of the polypropylene composite material according to any one of claims 1 to 5 or the polypropylene composite material prepared by the preparation method according to any one of claims 6 to 7, or the polypropylene composite product according to claim 8 or the polypropylene composite product prepared by the preparation method according to claim 9 in the field of packaging.

Images