A polypropylene composite material, its preparation method and application

Abstract

The present invention relates to a polypropylene composite material, a preparation method and an application thereof, belonging to the technical field of general plastics. The polypropylene composite material described in the present invention comprises the following components in parts by weight: 68 - 82 parts of polypropylene resin, 18 - 35 parts of talcum powder, 4 - 11 parts of octabromodiphenyl ether additives, and 0.8 - 2.5 parts of sorbitol nucleating agent; the mesh number of the talcum powder is 750 - 2000 mesh. The present invention combines octabromodiphenyl ether additives, talcum powder with a specific mesh number, and sorbitol nucleating agent with polypropylene, so that the prepared polypropylene composite material can maintain high elasticity at normal temperature and is easy to shape at high temperature.

Description

Technical Field

[0001] The present invention belongs to the technical field of general plastics, and particularly relates to a polypropylene composite material, a preparation method thereof, and an application thereof. Background Art

[0002] Polyolefin materials belong to semi-crystalline materials, with crystalline regions and amorphous regions. During the stress application process of the materials, when the deformation amount is small, the material mainly undergoes elastic deformation macroscopically, and this deformation can recover after the external stress is removed; when the deformation amount continues to increase, the material macroscopically shows elastic deformation and plastic deformation, and only part of this deformation can recover after the external stress is removed; when the deformation amount is further increased, the material is macroscopically plastic deformation, and this deformation cannot recover after the external stress is removed, resulting in permanent deformation; generally speaking, different application scenarios have different requirements for the plastic deformation and elastic deformation of polyolefin materials; for some special scenarios, such as cable protection pipes, polyolefin materials are required to have high elasticity at room temperature and be easily plasticized at high temperature.

[0003] CN114410005A discloses an anti-bending and flame-retardant polypropylene composite material and a preparation method thereof. Through the composite modification of polyolefin elastomers, the obtained composite material has excellent anti-bending performance and a high material rebound rate; however, this technology does not explore the mechanical properties of the polypropylene composite material at high temperature.

[0004] CN114163723A discloses a polypropylene composition and a preparation method thereof. By introducing micron-sized calcium carbonate and metallocene linear low-density polyethylene into the polypropylene resin, the polypropylene material rapidly enters the yield stage of plastic deformation during the deformation process, generating irreversible plastic deformation; the polypropylene composition described in the present invention does not have high-elasticity performance at room temperature and is not suitable for use in the preparation of cable protection pipes.

[0005] Aiming at the problems existing in the above polyolefin materials, developing a polypropylene composite material that is easily plasticized at high temperature and can maintain high elasticity at room temperature is the current research focus. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a polypropylene composite material that is easily plasticized at high temperature and can maintain high elasticity at room temperature, a preparation method thereof, and an application thereof.

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

[0008] In a first aspect, the present invention provides a polypropylene composite material, which comprises the following components in parts by weight: 68 - 82 parts of polypropylene resin, 18 - 35 parts of talcum powder, 4 - 11 parts of octabromodiphenyl ether additive, and 0.8 - 2.5 parts of sorbitol nucleating agent;

[0009] The mesh number of the talcum powder is 750 - 2000 mesh.

[0010] The mesh number of the talcum powder is tested using a mesh ruler and refers to the ISO 565 - 1984 standard for testing.

[0011] The inventors introduced octabromodiphenyl ether additive into the above formula; the octabromodiphenyl ether additive has a relatively low melting point. During the extrusion granulation process of the polypropylene composite material, the solid particles of this additive can be evenly distributed in the matrix of polypropylene, acting as a nano - filler, enhancing the heterogeneous nucleation ability, and improving the strength and anti - deformation ability of the final composite material; at the same time, due to the relatively low viscosity of the molten octabromodiphenyl ether additive, when the material is in a high - temperature environment, the octabromodiphenyl ether melts, which can promote the movement of molecular segments, easily cause the slip of lamellar crystals and the destruction and recombination of crystal region structures, driving the material into the yield state, causing the material to have permanent deformation, and having good plasticity at high temperatures.

[0012] Secondly, the present invention uses talcum powder with a large particle size of 750 - 2000 mesh. Compared with traditional fine - particle - size talcum powder, the talcum powder of the present invention can play a supporting role in the resin, increasing the modulus of the material and better improving the ability of the polypropylene composite material to resist deformation at room temperature; when in a high - temperature state, due to the deformation of the polypropylene material, the large - particle - size talcum powder is more likely to form a "carding" effect during the deformation process, resisting the subsequent rebound of the material, thus playing a better role in high - temperature plastic shaping.

[0013] In addition, the inventors also introduced sorbitol nucleating agent into the formula. Compared with benzoate and phosphate nucleating agents, the sorbitol nucleating agent can play a better role in refining the grains of polypropylene and can form a three - dimensional network structure during the processing, providing more fulcrums for the heterogeneous nucleation of polypropylene; in addition, the sorbitol nucleating agent only provides more heterogeneous nucleation points but does not promote the elongation of crystal nuclei. Therefore, to a certain extent, it avoids the imperfect lamellar crystals formed during the rapid growth of crystal nuclei, further avoiding the yield and permanent deformation of the composite material and providing a higher elastic recovery ability; the inventors also found that the addition of too much sorbitol nucleating agent will cause an increase in the melting temperature of the crystal region, increasing the perfection degree of the crystal region, and making it difficult to achieve the destruction and recombination of the crystal region during the plastic deformation process, resulting in a decrease in the permanent deformation ability of the material.

[0014] The inventors found that the octabromoether additive, the sorbitol nucleating agent and the talc powder with a mesh size of 750-2000 in the present invention work together to make the final polypropylene composite material have the shaping ability at high temperature and high elasticity at room temperature.

[0015] As a preferred embodiment of the polypropylene composite material of the present invention, in the polypropylene composite material, the weight proportion of the polypropylene resin is one of 68 parts, 72 parts, 76 parts, 80 parts, 82 parts or any two of the range values; the weight proportion of the talc is one of 18 parts, 23 parts, 28 parts, 30 parts, 35 parts or any two of the range values; the weight proportion of the octabromoether additive is one of 4 parts, 7 parts, 9 parts, 11 parts or any two of the range values; the weight proportion of the sorbitol nucleating agent is one of 0.8 parts, 1 parts, 1.4 parts, 1.7 parts, 2.1 parts, 2.5 parts or any two of the range values.

[0016] As a preferred embodiment of the polypropylene composite material of the present invention, the mesh size of the talcum powder is 1200-1600 meshes. The inventors have found through a large number of experiments that when the mesh size of the talcum powder is within the above range, the polypropylene can have a better ability to resist deformation at room temperature, and at high temperatures, it is easier to form a "card" effect during the deformation process, resist the rebound of subsequent materials, and make the product more plastic at high temperatures.

[0017] As a preferred embodiment of the polypropylene composite material of the present invention, the mass ratio of the talc powder, the octabromoether additive and the sorbitol nucleating agent is talc powder: octabromoether additive: sorbitol nucleating agent = 20-30: 5-10: 1-2.

[0018] As a preferred embodiment of the polypropylene composite material of the present invention, the octabromoether additive is at least one of tetrabromobisphenol A-bis(2,3-dibromopropyl ether) (BDDP) and tetrabromobisphenol S bis(2,3-dibromopropyl) ether (TBBP-DBPE).

[0019] As a preferred embodiment of the polypropylene composite material of the present invention, the sorbitol nucleating agent includes at least one of unsubstituted dibenzylidene sorbitol (DBS), (1,3,2,4-di(p-methyldibenzylidene) sorbitol (MDBS), (1,3,2,4)-di(3,4-dimethyl)benzylidene sorbitol (DMDBS), and a condensate of n-propylbenzaldehyde-n-propyl sorbitol.

[0020] As a preferred embodiment of the polypropylene composite material of the present invention, the polypropylene resin is at least one of homopolypropylene and copolymer polypropylene, and the melt flow rate of the polypropylene resin measured at 230° C. and 2.16 kg according to ISO1133-2022 is 0.1-10 g / 10 min.

[0021] As a preferred embodiment of the polypropylene composite material of the present invention, the components of the polypropylene composite material further include 1-5 parts of processing aids.

[0022] As a more preferred embodiment of the polypropylene composite material of the present invention, the processing aids include at least one of a lubricant and an antioxidant.

[0023] As a more preferred embodiment of the polypropylene composite material of the present invention, the antioxidant includes at least one of a hindered phenol antioxidant, a phosphite antioxidant, a phenolic antioxidant, and a divalent sulfur antioxidant; and / or, the lubricant includes at least one of an amide lubricant, a metal soap lubricant, a stearic acid composite ester lubricant, and a low molecular weight lipid lubricant.

[0024] As a preferred embodiment of the polypropylene composite material of the present invention, in the polypropylene composite material of the present invention, the content of the polypropylene resin is not less than 55 wt%.

[0025] As a preferred embodiment of the polypropylene composite material of the present invention, without affecting the technical effects of the present invention, a toughening agent, a weathering agent, an antistatic agent, a coloring agent, etc. can also be added.

[0026] In a second aspect, the present invention provides a method for preparing the above polypropylene composite material, including the following steps:

[0027] S1. Weigh each component in the polypropylene composite material according to the ratio, mix them evenly to obtain a premix.

[0028] S2. Perform melt extrusion and pellet drying on the premix obtained in step S1 to obtain the polypropylene composite material.

[0029] As a preferred embodiment of the method for preparing the polypropylene composite material of the present invention, in step S2, the process parameters of the melt extrusion are: the temperature of the plasticizing section is 190-210°C, and the die head temperature is 200-220°C; the traction speed during pellet drying is 100-200 mm / s.

[0030] In a third aspect, the present invention provides the application of the above polypropylene composite material in the preparation of a high-temperature heat-set polypropylene material for pipes, especially in the application of cable protection pipes.

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] The present invention provides a polypropylene composite material, which is compounded with octabromodiphenyl ether additives, talcum powder with a specific mesh number, sorbitol nucleating agents and polypropylene, so that the prepared polypropylene composite material can maintain high elasticity at room temperature and is easy to shape at high temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the elastic recovery ability test of the polypropylene composite material of the present invention at room temperature and the plastic deformation ability test at high temperature. DETAILED DESCRIPTION OF THE INVENTION

[0034] The technical solutions of the present invention will be further described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work belong to the scope of protection of the present invention. The methods or operations used in the embodiments are conventional methods or conventional operations in the art unless otherwise specified.

[0035] Among them, the processing aids are selected as antioxidants and lubricants. The antioxidant is antioxidant 1010 and antioxidant 168, and the mass ratio of the two is 1:1, both of which are conventional commercially available products; the lubricant is calcium stearate lubricant; in the present invention, the mass ratio of the antioxidant to the lubricant is antioxidant: lubricant = 1:1.

[0036] The raw materials used in the examples and comparative examples are described as follows, but are not limited to these materials:

[0037] Homopolypropylene resin 1 (PP 1): PP T30S, melt flow rate of 3.0 g / 10 min (test conditions: 230 °C, 2.16 kg, ISO1133), PetroChina Dushanzi Petrochemical Company.

[0038] Homopolypropylene resin 2 (PP 2): PP B1101, melt flow rate of 0.2 g / 10 min (test conditions: 230 °C, 2.16 kg, ISO1133), Formosa Plastics.

[0039] Homopolypropylene resin 3 (PP 3): PP 05H82-AV, melt flow rate of 5.0 g / 10 min (test conditions: 230 °C, 2.16 kg, ISO1133), Columbia Polipropileno.

[0040] Copolypropylene resin (PP 4): PP LH-K8003, melt flow rate of 3 g / 10 min (test conditions: 230 °C, 2.16 kg, ISO1133), Lihe Zhixin New Material Technology Co., Ltd.

[0041] Talcum powder 6: Mesh number is 400 mesh, TY90-20-C, Longguang talc.

[0042] Talcum powders 1-5 are granular talcum powders with a particle size of 800-3000 mesh obtained by crushing and screening talcum powder 1; specifically:

[0043] Talcum powder 1: Mesh number is 1250 mesh.

[0044] Talcum powder 2: Mesh number is 800 mesh.

[0045] Talcum powder 3: Mesh number is 1500 mesh.

[0046] Talcum powder 4: Mesh number is 2000 mesh.

[0047] Talcum powder 5: Mesh number is 3000 mesh.

[0048] Wollastonite, mesh number is 2000 mesh, obtained by crushing and screening HQ-1250 wollastonite with a mesh number of 1250 produced by Dalian Global Minerals Co., Ltd.

[0049] Calcium carbonate, mesh number is 2000 mesh, CC-1250, Jiangxi Guangyuan Sales Co., Ltd.

[0050] Mica, mesh number is 2000 mesh, obtained by crushing and screening mica-P325 with a mesh number of 325 produced by Jiangmen Jingda Mica Materials Co., Ltd.

[0051] Kaolin, mesh number is 2000 mesh, BRITEX-95, Shanxi Jinyu Kelin Technology Co., Ltd.

[0052] Montmorillonite, mesh number is 2000 mesh, Montmorillonite-I.44P, Beijing Yiweit Special Chemical Technology Development Co., Ltd.

[0053] Nucleating agent 1: Sorbitol-based nucleating agent, NX-8000K, American Melink.

[0054] Nucleating agent 2: Phosphate-based nucleating agent, NA-18, Japanese Adeka.

[0055] Octabromodiphenyl ether additive (bromine-based additive 1): Tetrabromobisphenol A-bis(2,3-dibromopropyl ether), commercially available.

[0056] Melamine hydrobromide (bromine-based additive 2), commercially available.

[0057] Decabromodiphenylethane (bromine-based additive 3), commercially available.

[0058] Ethylenebis(tetrabromophthalimide) (bromine-based additive 4), commercially available.

[0059] Examples 1-10 and Comparative Examples 1-17

[0060] Examples 1-10 and Comparative Examples 1-17 are polypropylene composites of the present invention; the components and their parts by weight of the polypropylene composites of Examples 1-10 and Comparative Examples 1-17 are shown in Tables 1-4.

[0061] The preparation method of the polypropylene composites of Examples 1-10 and Comparative Examples 1-17 comprises the following steps:

[0062] S1. Weigh each component in the polypropylene composite according to the proportion, mix evenly to obtain a premix;

[0063] S2. Carry out melt extrusion and pellet drying of the premix in step S1 in a twin-screw extruder to obtain the polypropylene composite; wherein, the process parameters of the melt extrusion are: the temperature of the plasticizing section is 190-210°C, and the die head temperature is 200-220°C; the traction speed during pellet drying is 100-200 mm / s.

[0064] Table 1

[0065]

[0066]

[0067] Table 2

[0068]

[0069]

[0070] Table 3

[0071]

[0072] Table 4

[0073]

[0074]

[0075] Performance Test

[0076] The polypropylene composites of Examples 1-10 and Comparative Examples 1-17 of the present invention are injection molded into 100 mm × 10 mm × 4 mm splines for the following tests:

[0077] (1) Elastic recovery ability test at room temperature: The splines are arranged as follows Figure 1It is placed in an environment at room temperature of 23°C. An external force is applied to the end of the spline away from the tabletop, and the spline is pressed downwards. When the end point of the end of the spline is at a distance H0 from before deformation, the external force is released, and the maximum height H1 that the non-end point of the spline can recover is recorded (the height of the non-externally-force-applied end point of the spline is 0). The resilience degree S of the material = (H0 - H1) / H0 * 100%. The resilience degree S represents the elastic recovery performance of the material.

[0078] (2) Test of plastic deformation ability at high temperature: The spline is placed as shown in Figure 1 in an environment at a temperature of 110°C. An external force is applied to the end of the spline away from the tabletop, and the spline is pressed downwards. When the end point of the end of the spline is at a distance H from before deformation, the deformation is maintained for 5 minutes and then the external force is released. The spline is then placed at room temperature to cool, and the maximum height H' that the non-end point of the spline can recover after 24 hours of room temperature adjustment is recorded (the height of the non-externally-force-applied end point of the spline is 0). The plastic deformation ability (P) of the material can be expressed as the maximum height of the end of the spline after the external force is removed / the height during the external force application, that is, P = (H' / H) * 100%.

[0079] The test results are shown in Table 5 below.

[0080] Table 5

[0081]

[0082]

[0083] It can be seen from Table 5 that when the technical solution of the present invention is adopted, the obtained product has excellent resilience at 23°C at room temperature and excellent plastic forming ability at 110°C at high temperature; specifically, the plastic deformation ability at 110°C at high temperature is greater than 85%, and the elastic recovery ability at 23°C is greater than or equal to 90%.

[0084] By comparing Examples 1-3, Example 9 and Comparative Examples 1 and 2, it can be seen that the particle size of talcum powder can affect the plastic deformation ability of the product at high temperature; when the mesh number of talcum powder is in the range of 1200 - 1600, the obtained polypropylene composite material has better plastic forming ability at high temperature and elastic recovery ability at room temperature; specifically: the plastic deformation ability at 110°C at high temperature is greater than or equal to 88%, and at the same time, the elastic recovery ability at 23°C is greater than or equal to 93%.

[0085] Comparing Example 1 and Comparative Example 3, it can be seen that the use of sorbitol nucleating agents in the present invention can improve to a certain extent the plastic deformation ability of the final product at high temperatures and the resilience performance at room temperature compared with phosphate nucleating agents; when sorbitol nucleating agents are used, the obtained product has better resilience at 23 °C room temperature and better plastic forming ability at 110 °C high temperature.

[0086] Comparing Example 1 and Comparative Examples 4-9, it can be seen that whether the addition amounts of talc, BDDP, and sorbitol nucleating agents are not within the scope of the present invention, it will affect the plastic deformation ability of the product at high temperatures and the resilience performance at room temperature; the resilience degree of the products in Comparative Examples 5-9 and / or the plastic deformation ability at 110 °C high temperature decreased significantly compared with that of the examples.

[0087] Comparing Example 1 and Comparative Examples 10-14, it can be seen that the use of talc as a filler in the present invention can improve to a certain extent the plastic deformation ability of the final product at high temperatures and the resilience performance at room temperature compared with other fillers; when talc is used as a filler, the obtained product has better resilience at 23 °C room temperature and better plastic forming ability at 110 °C high temperature.

[0088] Comparing Example 1 and Comparative Examples 15-17, it can be seen that when octabromodiphenyl ether additives are used in the present invention, compared with other bromine-based additives, it can improve to a certain extent the plastic deformation ability of the final product at high temperatures and the resilience performance at room temperature; when octabromodiphenyl ether additives are used, the obtained product has better resilience at 23 °C room temperature and better plastic forming ability at 110 °C high temperature.

[0089] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A polypropylene composite material, characterized in that, The polypropylene composite material comprises the following components in parts by weight: 68 - 82 parts of polypropylene resin, 18 - 35 parts of talcum powder, 4 - 11 parts of octabromoether additive, and 0.8 - 2.5 parts of sorbitol nucleating agent; the mesh number of the talcum powder is 750 - 2000 mesh; the octabromoether additive is at least one of tetrabromobisphenol A - bis(2,3 - dibromopropyl ether) and tetrabromobisphenol S bis(2,3 - dibromopropyl) ether.

2. The polypropylene composite material according to claim 1, characterized in that, The mesh number of the talcum powder is 1200 - 1600 mesh.

3. The polypropylene composite material according to claim 1, characterized in that, The mass ratio of the talcum powder, octabromoether additive, and sorbitol nucleating agent is talcum powder: octabromoether additive: sorbitol nucleating agent = 20 - 30:5 - 10:1 - 2.

4. The polypropylene composite material according to claim 1, characterized in that, The sorbitol nucleating agent is at least one of unsubstituted dibenzylidene sorbitol, (1,3,2,4)-bis(p - methyl dibenzylidene) sorbitol, (1,3,2,4)-bis(3,4 - dimethyl) benzylidene sorbitol, and the condensate of n - propylbenzaldehyde - n - propyl sorbitol.

5. The polypropylene composite material according to claim 1, characterized in that, The polypropylene resin is at least one of homopolypropylene and copolymerized polypropylene, and the melt flow rate of the polypropylene resin measured according to ISO1133 at 230°C and 2.16 kg is 0.1 - 10 g / 10 min.

6. The polypropylene composite material according to claim 1, characterized in that, The components of the polypropylene composite material further include 1 - 5 parts of processing aids.

7. The polypropylene composite material according to claim 6, characterized in that, The processing aids include antioxidants and lubricants.

8. The preparation method of the polypropylene composite material according to any one of claims 1-7, characterized in that, Comprising the following steps: S1. Weigh each component in the polypropylene composite material in proportion and mix them evenly to obtain a premix. S2. Melt - extrude and granulate - dry the premix in step S1 to obtain the polypropylene composite material.

9. The application of the polypropylene composite material according to any one of claims 1 - 7 in the preparation of a high - temperature heat - setting polypropylene material for pipes.

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