Polypropylene composite and method for producing the same

Abstract

The application discloses a kind of polypropylene composite material and preparation method thereof, polypropylene composite material includes 65-90 weight parts polypropylene and 5-20 weight parts CaCO3 Whisker slurry;Polypropylene includes one or more of copolymerization polypropylene and homopolymerization polypropylene;CaCO3 Whisker slurry includes the following preparation steps: in CaCl2 aqueous solution, MgCl2 is added, stirring, CO2 gas is introduced, carbonization reaction, stirring again, mineralization is placed, and CaCO3 whisker mixture is prepared;Dopamine hydrochloride is added in CaCO3 whisker mixture, stirring, PH value is adjusted, oxygen is introduced, and oxidation polymerization reaction is carried out, and surface modified CaCO3 whisker is prepared by filtering, washing;Deionized water and anhydrous ethanol are added, stirring again, and CaCO3 whisker slurry is prepared;The polypropylene composite material of the application can greatly reduce the VOC content in material, and the smell of material is reduced.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials, specifically relating to a polypropylene composite material and its preparation method. Background Technology

[0002] Lightweighting of automotive materials has become a significant trend in the industry. By replacing traditional materials with lightweight alternatives, vehicle weight can be reduced, leading to fuel savings. Low-density materials refer to materials whose density is lowered by reducing mineral filler without altering the shrinkage rate, thus achieving lightweight components. For example, PP+EPDM-T05 can replace PP+EPDM-T16, and PP+EPDM-T10 can replace PP+EPDM-T20. The challenge with these materials is reducing mineral filler while maintaining the material's original rigidity and toughness, and, most importantly, keeping the shrinkage rate constant.

[0003] In recent years, automobiles have become increasingly common in households, bringing great convenience and improving people's living standards. However, when automotive polymer materials are used as interior parts, they continuously release volatile organic compounds (VOCs) such as benzene, aldehydes, and trimethylolpropionic acid, causing deterioration of the in-car environment and harming human health. With increasing awareness of health and environmental protection, in-car air quality has become a growing concern. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a polypropylene composite material and its preparation method.

[0005] A polypropylene composite material comprises 71-85 parts by weight of polypropylene and 8-20 parts by weight of CaCO3 whisker slurry; the polypropylene comprises one or more of copolymer polypropylene and homopolymer polypropylene; the CaCO3 whisker slurry comprises the following preparation steps:

[0006] MgCl2 is added to an aqueous solution of CaCl2, stirred, and CO2 gas is introduced to induce a carbonization reaction. The mixture is then stirred again and allowed to stand for mineralization to obtain a CaCO3 whisker mixture.

[0007] Dopamine hydrochloride was added to the above CaCO3 whisker mixture, stirred, pH value was adjusted, oxygen was introduced to carry out oxidative polymerization reaction, and the mixture was filtered and washed to obtain surface-modified CaCO3 whiskers; deionized water and anhydrous ethanol were added, and the mixture was stirred again to obtain CaCO3 whisker slurry.

[0008] Preferably, it further includes 5-9 parts by weight of toughening agent; the toughening agent includes one or more of propylene-α-olefin copolymer, ethylene-propylene copolymer and ethylene-octene copolymer.

[0009] Preferably, it further includes 1-3 parts by weight of a compatibilizer; the compatibilizer includes one or more of maleic acid-grafted polypropylene, maleic anhydride-grafted polypropylene, acrylic acid-grafted polypropylene, and glycidyl acrylate-grafted polypropylene.

[0010] Preferably, it further includes 0.2-0.5 parts by weight of antioxidant; the antioxidant includes one or more of antioxidant 1010, antioxidant 1076, antioxidant 626, antioxidant 168 and antioxidant DSTP.

[0011] Preferably, it further includes 0.2-0.5 parts by weight of lubricant; the lubricant includes one or more of zinc stearate, calcium stearate, ethylene bis-stearamide, and pentaerythritol stearate.

[0012] Preferably, it further includes 0.4-0.8 parts by weight of light stabilizer and 0.5-1 parts by weight of colorant; the light stabilizer includes hindered amine light stabilizers.

[0013] Preferably, the molar ratio of MgCl2 to CaCl2 is 1:0.2-1:0.5.

[0014] Preferably, the concentration of the CaCl2 aqueous solution is 0.1-0.25 mol / L.

[0015] Preferably, the volume ratio of deionized water to anhydrous ethanol is 19:1.

[0016] A method for preparing a polypropylene composite material includes the following steps:

[0017] 71-85 parts by weight of polypropylene, 1-3 parts by weight of compatibilizer, 0.2-0.5 parts by weight of antioxidant, 5-9 parts by weight of toughening agent, 0.2-0.5 parts by weight of lubricant, 0.2-0.5 parts by weight of light stabilizer and 0.4-0.8 parts by weight of colorant are mixed, and then 8-20 parts by weight of CaCO3 whisker slurry are added. The polypropylene composite material is obtained by melting, extrusion and granulation.

[0018] The beneficial effects of this invention are:

[0019] This invention utilizes calcium carbonate whiskers to reinforce polypropylene materials, preparing low-density, high-modulus composite materials. The advantages of this invention are twofold: firstly, by directly using CaCO3 whisker slurry, it avoids the agglomeration of CaCO3 whisker powder caused by traditional drying processes, which affects the dispersion of the powder in the polymer matrix; secondly, VOCs such as pentabenzenetrialdehyde in polypropylene materials can dissolve in the aqueous solution and anhydrous ethanol of the CaCO3 whisker slurry. Through double vacuum extraction, the VOC content of the composite material can be significantly reduced, thus lessening its odor. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention have been clearly and completely described. 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.

[0021] Comparative Example 1:

[0022] The preparation method of low-odor, low-density, high-modulus polypropylene composite material includes the following steps:

[0023] Step 1: Add 200L of 0.1mol / L CaCl2 aqueous solution to the reactor, start the stirrer at 200rpm, and control the temperature at 70℃; then add the crystal form control agent MgCl2, with a molar ratio of crystal form control agent to CaCl2 of 0.2. After stirring for 30min, introduce CO2 gas until the pH of the reaction solution is 7-8, then stop the gas introduction to complete the carbonization reaction. Continue stirring for 1h, and then let it stand for 6h to mineralize, to obtain a CaCO3 whisker mixture.

[0024] Step 2: Add 10g of dopamine hydrochloride to the CaCO3 whisker mixture obtained in Step 1, start the stirrer at 50rpm, control the temperature at 30℃ and stir for 5min, then add Na2CO3 aqueous solution to adjust the pH value to 8-9, introduce oxygen and carry out oxidative polymerization reaction for 1h, then filter, wash and dry to obtain surface-modified CaCO3 whisker powder;

[0025] Step 3: Weigh out polypropylene, compatibilizer, antioxidant, lubricant, light stabilizer, and colorant by weight, mix them evenly in a high-speed mixer, and then feed them into a twin-screw extruder through the main feeder. Add CaCO3 whisker powder into the twin-screw extruder through the side feed port. The screw speed is 300 r / min, the extrusion temperature is 210℃, and the vacuum degree of the two vacuum pumps is -0.08 MPa to prepare a low-odor, low-density, high-modulus polypropylene composite material.

[0026] Comparative Example 2:

[0027] The preparation method of low-odor, low-density, high-modulus polypropylene composite material includes the following steps:

[0028] Step 1: Add 200L of 0.2mol / L CaCl2 aqueous solution to the reactor, start the stirrer at 300rpm, and control the temperature at 80℃; then add the crystal form control agent MgCl2, with a molar ratio of crystal form control agent to CaCl2 of 0.4. After stirring for 30min, introduce CO2 gas until the pH of the reaction solution is 7-8, then stop the gas introduction to complete the carbonization reaction. Continue stirring for 1h, and then let it stand for 8h to mineralize, to obtain a CaCO3 whisker mixture.

[0029] Step 2: Add 30g of dopamine hydrochloride to the CaCO3 whisker mixture obtained in Step 1, start the stirrer at 100rpm, control the temperature at 50℃ and stir for 5min, then add Na2CO3 aqueous solution to adjust the pH value to 8-9, introduce oxygen and carry out oxidative polymerization reaction for 2h, then filter, wash and dry to obtain surface-modified CaCO3 whisker powder;

[0030] Step 3: Weigh out polypropylene, compatibilizer, antioxidant, lubricant, light stabilizer, and colorant by weight, mix them evenly in a high-speed mixer, and then feed them into a twin-screw extruder through the main feeder. Add CaCO3 whisker powder into the twin-screw extruder through the side feed port. The screw speed is 250 r / min, the extrusion temperature is 200℃, and the vacuum degree of the two vacuum pumps is -0.09 MPa to prepare a low-odor, low-density, high-modulus polypropylene composite material.

[0031] Example 1:

[0032] The preparation method of low-odor, low-density, high-modulus polypropylene composite material includes the following steps:

[0033] Step 1: Add 200L of 0.1mol / L CaCl2 aqueous solution to the reactor, start the stirrer at 200rpm, and control the temperature at 70℃; then add the crystal form control agent MgCl2, with a molar ratio of crystal form control agent to CaCl2 of 0.2. After stirring for 30min, introduce CO2 gas until the pH of the reaction solution is 7-8, then stop the gas introduction to complete the carbonization reaction. Continue stirring for 1h, and then let it stand for 6h to mineralize, to obtain a CaCO3 whisker mixture.

[0034] Step 2: Add 10g of dopamine hydrochloride to the CaCO3 whisker mixture obtained in Step 1, start the stirrer at 50 rpm, control the temperature at 50℃ and stir for 5 minutes. Then add Na2CO3 aqueous solution to adjust the pH value to 8-9, introduce oxygen, and carry out an oxidative polymerization reaction for 1 hour. After filtration and washing, surface-modified CaCO3 whiskers are obtained. Then add a certain amount of deionized water and anhydrous ethanol (volume ratio of deionized water to anhydrous ethanol 19:1), stir at 200 rpm for 30 minutes to obtain a CaCO3 whisker slurry with a solid content of 60%.

[0035] Step 3: Weigh out polypropylene, compatibilizer, antioxidant, toughening agent, lubricant, light stabilizer, and colorant by weight, mix them evenly in a high-speed mixer, and then feed them into a twin-screw extruder through the main feeder. CaCO3 whisker slurry is pumped into the twin-screw extruder through a side feed port using a melt pump. The screw speed is 300 r / min, the extrusion temperature is 210℃, and the vacuum degree of the two vacuum pumps is -0.08 MPa to prepare a low-odor, low-density, high-modulus polypropylene composite material.

[0036] Example 2:

[0037] The preparation method of low-odor, low-density, high-modulus polypropylene composite material includes the following steps:

[0038] Step 1: Add 200L of 0.2mol / L CaCl2 aqueous solution to the reactor, start the stirrer at 300rpm, and control the temperature at 80℃; then add the crystal form control agent MgCl2, with a molar ratio of crystal form control agent to CaCl2 of 0.4. After stirring for 30min, introduce CO2 gas until the pH of the reaction solution is 7-8, then stop the gas introduction to complete the carbonization reaction. Continue stirring for 1h, and then let it stand for 8h to mineralize, to obtain a CaCO3 whisker mixture.

[0039] Step 2: Add 30g of dopamine hydrochloride to the CaCO3 whisker mixture obtained in Step 1, start the stirrer at 100rpm, control the temperature at 50℃ and stir for 5min. Then add Na2CO3 aqueous solution to adjust the pH value to 8-9, introduce oxygen and carry out oxidative polymerization reaction for 2h. After filtration and washing, obtain surface-modified CaCO3 whiskers. Then add a certain amount of deionized water and anhydrous ethanol (volume ratio of deionized water to anhydrous ethanol 19:1), stir at 250rpm for 30min to obtain CaCO3 whisker slurry with a solid content of 60%.

[0040] Step 3: Weigh out polypropylene, compatibilizer, antioxidant, toughening agent, lubricant, light stabilizer, and colorant by weight, mix them evenly in a high-speed mixer, and then feed them into a twin-screw extruder through the main feeder. CaCO3 whisker slurry is pumped into the twin-screw extruder through a side feed port using a melt pump. The screw speed is 250 r / min, the extrusion temperature is 200℃, and the vacuum degree of the two vacuum pumps is -0.09 MPa to prepare a low-odor, low-density, high-modulus polypropylene composite material.

[0041] Example 3:

[0042] The preparation method of low-odor, low-density, high-modulus polypropylene composite material includes the following steps:

[0043] Step 1: Add 200L of 0.25mol / L CaCl2 aqueous solution to the reactor, start the stirrer at 300rpm, and control the temperature at 90℃; then add the crystal form control agent MgCl2, with a molar ratio of crystal form control agent to CaCl2 of 0.5. After stirring for 30min, introduce CO2 gas until the pH of the reaction solution is 7-8, then stop the gas introduction to complete the carbonization reaction. Continue stirring for 1h, and then let it stand for 9h to mineralize, to obtain a CaCO3 whisker mixture.

[0044] Step 2: Add 40g of dopamine hydrochloride to the CaCO3 whisker mixture obtained in Step 1, start the stirrer at 100rpm, control the temperature at 40℃ and stir for 5min. Then add Na2CO3 aqueous solution to adjust the pH value to 8-9, introduce oxygen and carry out oxidative polymerization reaction for 2h. After filtration and washing, obtain surface-modified CaCO3 whiskers. Then add a certain amount of deionized water and anhydrous ethanol (deionized water to anhydrous ethanol volume ratio 19:1), stir at 200rpm for 30min to obtain CaCO3 whisker slurry with a solid content of 60%.

[0045] Step 3: Weigh out polypropylene, compatibilizer, antioxidant, toughening agent, lubricant, light stabilizer, and colorant by weight, mix them evenly in a high-speed mixer, and then feed them into a twin-screw extruder through the main feeder. CaCO3 whisker slurry is pumped into the twin-screw extruder through a side feed port using a melt pump. The screw speed is 400 r / min, the extrusion temperature is 210℃, and the vacuum degree of the two vacuum pumps is -0.09 MPa to prepare a low-odor, low-density, high-modulus polypropylene composite material.

[0046] The compositions of the raw materials used in Examples 1-3 and Comparative Examples 1-2 are shown in Table 1 below:

[0047] Table 1 Composition of raw materials for preparation

[0048]

[0049] The glass fiber reinforced polypropylene composites prepared in Comparative Examples 1-2 and Examples 1-3 were subjected to mechanical property tests according to relevant testing standards. The test results are shown in Table 2 below:

[0050] Table 2 Results of Physical Performance Tests

[0051]

[0052]

[0053] The test results from Comparative Example 1 and Example 1, and Comparative Example 2 and Example 2, demonstrate that directly using CaCO3 whisker slurry avoids the agglomeration of CaCO3 whisker powder caused by traditional drying processes. This allows for excellent and uniform dispersion of the powder within the polymer matrix, significantly improving the mechanical properties of the composite material. Furthermore, VOCs such as pentabenzenetrialdehyde in polypropylene materials are soluble in the aqueous solution and anhydrous ethanol of the CaCO3 whisker slurry. Combined with a dual vacuum extraction process, this significantly reduces the VOC content of the composite material and lessens its odor.

[0054] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0055] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A polypropylene composite material, characterized in that, It comprises the following components by weight: 71-85 parts polypropylene, 8-20 parts CaCO3 whisker slurry, 5-9 parts toughening agent, 1-3 parts compatibilizer, 0.2-0.5 parts antioxidant, 0.2-0.5 parts lubricant, 0.2-0.5 parts light stabilizer, and 0.4-0.8 parts colorant; The polypropylene includes one or more of copolymer polypropylene and homopolymer polypropylene; The CaCO3 whisker slurry includes the following preparation steps: MgCl2 is added to an aqueous solution of CaCl2, stirred, and CO2 gas is introduced to induce a carbonization reaction. The mixture is then stirred again and allowed to stand for mineralization to obtain a CaCO3 whisker mixture. Dopamine hydrochloride was added to the above CaCO3 whisker mixture, stirred, pH value was adjusted, oxygen was introduced to carry out oxidative polymerization reaction, and the mixture was filtered and washed to obtain surface-modified CaCO3 whiskers; deionized water and anhydrous ethanol were added, and the mixture was stirred again to obtain CaCO3 whisker slurry. The preparation method of the polypropylene composite material includes the following steps: 71-85 parts by weight of polypropylene, 1-3 parts by weight of compatibilizer, 0.2-0.5 parts by weight of antioxidant, 5-9 parts by weight of toughening agent, 0.2-0.5 parts by weight of lubricant, 0.2-0.5 parts by weight of light stabilizer and 0.4-0.8 parts by weight of colorant are mixed, and then 8-20 parts by weight of CaCO3 whisker slurry are added. The polypropylene composite material is obtained by melting, extrusion and granulation. The pentabenzenetrialdehyde (VOC) in polypropylene materials is dissolved in the aqueous solution of CaCO3 whisker slurry and anhydrous ethanol. Through double vacuum extraction, the VOC content of the composite material is reduced, and the odor of the composite material is alleviated.

2. The polypropylene composite material according to claim 1, characterized in that, The toughening agent includes one or more of propylene-α-olefin copolymers, ethylene-propylene copolymers, and ethylene-octene copolymers.

3. The polypropylene composite material according to claim 1, characterized in that, The compatibilizer includes one or more of maleic acid-grafted polypropylene, maleic anhydride-grafted polypropylene, acrylic acid-grafted polypropylene, and glycidyl acrylate-grafted polypropylene.

4. The polypropylene composite material according to claim 1, characterized in that, The antioxidants include one or more of antioxidants 1010, 1076, 626, 168, and DSTP.

5. The polypropylene composite material according to claim 1, characterized in that, The lubricant includes one or more of zinc stearate, calcium stearate, ethylene bis-stearamide, and pentaerythritol stearate.

6. The polypropylene composite material according to claim 1, characterized in that, The light stabilizer includes hindered amine light stabilizers.

7. The polypropylene composite material according to claim 1, characterized in that, The molar ratio of MgCl2 to CaCl2 is 1:0.2-1:0.

5.

8. The polypropylene composite material according to claim 1, characterized in that, The concentration of the CaCl2 aqueous solution is 0.1-0.25 mol / L.

9. The polypropylene composite material according to claim 1, characterized in that, The volume ratio of deionized water to anhydrous ethanol is 19:1.

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