Composite fiber modified polypropylene material and preparation method thereof

Abstract

The invention discloses a composite fiber modified polypropylene material and a preparation method thereof, and belongs to the technical field of high polymer materials, the composite fiber modified polypropylene material comprises the following raw materials by weight: 50-80 parts of polypropylene resin, 5-20 parts of composite fiber, 3-5 parts of a compatilizer, 0.5-2 parts of a lubricant, and 0.1-0.5 part of an antioxidant. The preparation method comprises the following steps: weighing the polypropylene resin, the composite fiber, the compatilizer, the lubricant and the antioxidant in parts by weight, and adding the materials into a mixing mill for mixing to obtain a premix; and then putting the obtained premix into a double-screw extruder for melt blending, and carrying out extrusion granulation to obtain the composite material modified polypropylene material. The composite fiber modified polypropylene material prepared in the invention has good mechanical properties, moisture resistance, heat resistance and corrosion resistance, and has wide application in the fields of medical treatment, household appliances, automobiles, spaceflight and the like as engineering plastic.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a composite fiber modified polypropylene material and a preparation method thereof. Background Art

[0002] Polypropylene (PP) is an excellent thermoplastic synthetic resin, which is widely used as a general-purpose resin. At the same time, polypropylene has good corrosion resistance and stability and is not easy to decompose. With the development of science and technology and the progress of industry, the demand for high-performance composite materials is increasing. Fiber-reinforced polypropylene composite materials have excellent mechanical properties, thermal stability and corrosion resistance. Compared with traditional plastics, fiber-reinforced polymer materials can give them higher mechanical properties and thermal deformation properties, further accelerating the trend of "replacing steel with plastics", and are widely used in the fields of automobiles, aerospace, electronics and construction.

[0003] In recent years, the research on the comprehensive performance of fiber-reinforced polypropylene resin has been increasing. However, the development and application of fiber-composite polypropylene materials also face many problems. For example, there is a lack of good compatibility between polar, hydrophilic fibers and non-polar, hydrophobic resin matrix, so that the interfacial bonding performance is relatively poor. Furthermore, due to the poor melt fluidity of the matrix, the dispersion of the filler is often uneven, which leads to defects such as the overall performance of the composite material being reduced. The Chinese patent with the authorization announcement number CN 110922615B discloses a preparation method of waste polyester fabric reinforced polypropylene composite plastic, including surface finishing, cleaning, crushing, modification and co-extrusion, and granulation. In the above-mentioned polyester fiber reinforced composite plastic, the interface bonding between the polyester fiber and the polymer matrix is ​​poor, and the traditional surface treatment and the method of adding an interfacial compatibilizer, such as maleic anhydride grafted polypropylene, is only more favorable to the three mechanical performance indicators of tensile strength, flexural strength, and flexural modulus, but has no positive effect on the two mechanical performance indicators of elongation at break and impact strength, and it is difficult to have a good dispersion and volume expansion effect on the material, which ultimately leads to poor comprehensive mechanical properties of the composite material. Chinese patent CN 201310354642.7 discloses a preparation method, which first pre-treats basalt fiber with a coupling agent, then crushes it into basalt fiber fine powder, and then mixes it with polypropylene and additives for extrusion granulation to obtain a basalt fiber reinforced polypropylene composite material. However, the tensile strength and bending modulus, heat deformation temperature, moisture and heat aging resistance, and scratch resistance of the polypropylene material prepared by this method are all low, which cannot meet the stringent use requirements of composite materials in a variety of complex environments.

[0004] Therefore, how to obtain a polypropylene material with excellent mechanical properties is still a problem that needs to be solved urgently. Summary of the invention

[0005] The purpose of the present invention is to provide a composite fiber modified polypropylene material and a preparation method thereof, so as to solve the problem that the mechanical properties of the polypropylene material in the prior art are poor.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] The first aspect of the present invention provides a composite fiber modified polypropylene material, which comprises the following raw materials in parts by weight:

[0008] Polypropylene resin: 50-80 parts;

[0009] Composite fiber: 5-20 parts;

[0010] Compatibilizer: 3-5 parts;

[0011] Lubricant: 0.5-2 parts;

[0012] Antioxidant: 0.1-0.5 parts;

[0013] The composite fiber is prepared by the following steps:

[0014] Add the modified basalt fiber to the hydrochloric acid solution, add xylan, stir for 10-15 minutes, introduce ammonia, condense and reflux at 30-35°C and stir for 20-30 minutes, adjust the pH value to 7.0-7.5, continue to stir and react for 6-7 hours, centrifuge and wash, and vacuum dry to obtain composite fiber. Xylan has good film-forming properties and biocompatibility, but due to the rich hydroxyl groups on the xylan unit, it has strong water absorption. After reacting with 3-mercaptopropyltrimethoxysilane grafted on the surface of the modified basalt fiber, its hydrophilicity is improved. When added to the polypropylene material, it forms a stable cross-linked structure with the polypropylene molecules, which improves the barrier properties and surface hydrophobicity of the polypropylene material.

[0015] Furthermore, the usage ratio of the modified basalt fiber, the hydrochloric acid solution and the xylan is 1.0-1.2 g:50 mL:0.50-0.55 g.

[0016] Further, the modified basalt fiber is prepared by the following steps:

[0017] The basalt fiber was added to deionized water and anhydrous ethanol, ultrasonically dispersed for 30 minutes, and then 3-mercaptopropyltrimethoxysilane was added, the pH was adjusted to 4.0-5.0, the temperature was raised to 80-85°C, stirred for 1-2 hours, centrifuged and washed, and dried to obtain modified basalt fiber. The basalt fiber was modified with 3-mercaptopropyltrimethoxysilane. The treated basalt fiber can be evenly dispersed in polypropylene, improving the interfacial compatibility with polypropylene, thereby improving the mechanical properties of basalt fiber reinforced polypropylene materials.

[0018] Furthermore, the usage ratio of basalt fiber, deionized water, anhydrous ethanol and 3-mercaptopropyltrimethoxysilane is 3.0-3.5 g: 45 mL: 5 mL: 2.0-2.3 g.

[0019] Furthermore, the compatibilizer is at least one of maleic anhydride grafted polypropylene, maleic anhydride grafted ethylene-octene and maleic anhydride grafted ethylene-vinyl acetate.

[0020] Furthermore, the lubricant is ethylene bisstearamide.

[0021] Furthermore, the antioxidant is at least one of a hindered phenol antioxidant and a phosphite antioxidant.

[0022] A second aspect of the present invention provides a method for preparing a composite fiber modified polypropylene material, comprising the following steps:

[0023] S1. Add basalt fiber to deionized water and anhydrous ethanol, ultrasonically disperse for 30 minutes, then add 3-mercaptopropyltrimethoxysilane, adjust the pH to 4.0-5.0, heat to 80-85°C, stir and react for 1-2 hours, centrifuge and wash, and dry to obtain modified basalt fiber;

[0024] S2, adding the modified basalt fiber to the hydrochloric acid solution, adding xylan, stirring for 10-15 minutes, introducing ammonia, condensing and refluxing at 30-35°C and stirring for 20-30 minutes, adjusting the pH value to 7.0-7.5, continuing to stir and react for 6-7 hours, centrifugally washing, and vacuum drying to obtain composite fibers;

[0025] S3, weighing by weight, adding polypropylene resin, composite fiber, compatibilizer, lubricant, and antioxidant into a mixer and mixing to obtain a premix;

[0026] S4, putting the obtained premix into a twin-screw extruder for melt blending, extruding and granulating to obtain a composite material modified polypropylene material.

[0027] Furthermore, in S3, the mixing temperature is 170-180° C., and the mixing time is 5-15 min.

[0028] Furthermore, in the twin-screw extruder in S4, the temperature of zone 1 is 180-200°C, the temperature of zone 2 is 200-220°C, the temperature of zone 3 is 190-210°C, the temperature of zone 4 is 180-210°C, the temperature of zone 5 is 170-190°C, and the die head temperature is 180-195°C.

[0029] Beneficial effects of the present invention:

[0030] The present invention provides a method for preparing a composite fiber modified polypropylene material, wherein polypropylene resin, composite fiber, compatibilizer, lubricant and antioxidant are mixed, and then melt extruded and granulated to obtain a polypropylene material. The obtained polypropylene material has excellent mechanical properties and moisture resistance, and the preparation method is reasonable in process, simple and easy to operate, and has strong operability and is suitable for large-scale production. The addition of composite fiber, on the one hand, fills polypropylene to play a skeleton role, which can improve the mechanical strength of the material; on the other hand, it can effectively inhibit the expansion of cracks during the fracture of the material, absorb impact energy, and thus achieve the effect of toughening. Due to its fine structure, compared with the addition of long fiber materials, composite fiber can overcome the shortcomings of poor dispersibility and poor surface finish of long fiber in composite materials. In addition, compared with single fiber reinforced polypropylene materials, composite fiber materials have many advantages. Appropriately adjusting the usage ratio between composite fibers has a positive effect on reducing the cost of polypropylene materials, which is more conducive to cost saving.

[0031] The composite fiber and the modified polypropylene material prepared in the present invention have good mechanical properties, moisture resistance, heat resistance and corrosion resistance, and are widely used as engineering plastics in the fields of medical treatment, home appliances, automobiles and aerospace. DETAILED DESCRIPTION

[0032] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Example 1

[0034] This embodiment provides a method for preparing a composite fiber modified polypropylene material, comprising the following steps:

[0035] S1. Add 3.0 g of basalt fiber to 45 mL of deionized water and 5 mL of anhydrous ethanol, and disperse by ultrasonic for 30 min. Then add 2.0 g of 3-mercaptopropyltrimethoxysilane, adjust the pH to 4.0, heat to 80 °C, stir and react for 1 h, centrifuge and wash, and dry to obtain modified basalt fiber.

[0036] S2, add 1.0g of modified basalt fiber to 50mL of hydrochloric acid solution (1wt%), add 0.50g of xylan, stir for 10-15min, introduce ammonia, condense and reflux at 30°C and stir for 20min, adjust the pH value to 7.0, continue stirring and reacting for 6-7h, centrifuge and wash, place in a 50°C vacuum drying oven and dry for 8h to obtain composite fiber;

[0037] S3, weighing by weight, adding 60 parts of polypropylene resin, 5 parts of composite fiber, 3 parts of maleic anhydride grafted polypropylene, 0.5 parts of ethylene bisstearic acid amide, and 0.1 parts of antioxidant 1010 into a mixer and mixing them at a mixing temperature of 170° C. for 5 min to obtain a premix;

[0038] S4. The obtained premix is ​​put into a twin-screw extruder for melt blending, wherein the temperature of zone 1 in the twin-screw extruder is 180°C, the temperature of zone 2 is 200°C, the temperature of zone 3 is 190°C, the temperature of zone 4 is 180°C, the temperature of zone 5 is 170°C, the temperature of the die head is 180°C, and extrusion granulation is performed to obtain a composite material modified polypropylene material.

[0039] The composite fiber modified polypropylene material is prepared through the above steps.

[0040] Example 2

[0041] Compared with Example 1, the only difference is:

[0042] S1. Add 3.5 g of basalt fiber to 45 mL of deionized water and 5 mL of anhydrous ethanol, and disperse by ultrasonic for 30 min. Then add 2.3 g of 3-mercaptopropyltrimethoxysilane, adjust the pH to 4.0, heat to 80 °C, stir and react for 1 h, centrifuge and wash, and dry to obtain modified basalt fiber.

[0043] Example 3

[0044] Compared with Example 1, the only difference is:

[0045] S2. Add 1.0 g of modified basalt fiber into 50 mL of hydrochloric acid solution (1 wt%), add 0.53 g of xylan, stir for 10-15 min, introduce ammonia, condense and reflux the reaction at 30 ° C and stir for 20 min, adjust the pH value to 7.0, continue stirring and reacting for 6-7 hours, centrifuge and wash, place in a 50 ° C vacuum drying oven and dry for 8 hours to obtain composite fibers.

[0046] Example 4

[0047] Compared with Example 1, the only difference is:

[0048] S2. Add 1.2 g of modified basalt fiber into 50 mL of hydrochloric acid solution (1 wt%), add 0.55 g of xylan, stir for 10-15 min, introduce ammonia, condense and reflux at 30 ° C and stir for 20 min, adjust the pH value to 7.0, continue stirring and reacting for 6-7 h, centrifuge and wash, place in a 50 ° C vacuum drying oven and dry for 8 h to obtain composite fibers.

[0049] Example 5

[0050] Compared with Example 1, the only difference is:

[0051] Replace 5 parts of composite fiber with 12 parts of composite fiber.

[0052] Example 6

[0053] Compared with Example 1, the only difference is:

[0054] Replace 5 parts of composite fiber with 19 parts of composite fiber.

[0055] Example 7

[0056] Compared with Example 1, the only difference is:

[0057] S3. Weigh by weight, add 75 parts of polypropylene resin, 15 parts of composite fiber, 4 parts of maleic anhydride grafted polypropylene, 1.5 parts of ethylene bisstearamide, and 0.3 parts of antioxidant 1010 into a mixer and mix them at a mixing temperature of 170° C. for 5 minutes to obtain a premix.

[0058] Example 8

[0059] Compared with Example 1, the only difference is:

[0060] S4. The obtained premix is ​​put into a twin-screw extruder for melt blending, wherein the temperature of zone 1 in the twin-screw extruder is 195°C, the temperature of zone 2 is 210°C, the temperature of zone 3 is 200°C, the temperature of zone 4 is 210°C, the temperature of zone 5 is 190°C, the temperature of the die head is 195°C, and extrusion granulation is performed to obtain a composite material modified polypropylene material.

[0061] Comparative Example 1

[0062] This comparative example provides a method for preparing a composite fiber modified polypropylene material, comprising the following steps:

[0063] S1, weighing by weight, adding 60 parts of polypropylene resin, 3 parts of maleic anhydride grafted polypropylene, 0.5 parts of ethylene bisstearic acid amide, and 0.1 parts of antioxidant 1010 into a mixer and mixing them at a mixing temperature of 170° C. for 5 min to obtain a premix;

[0064] S2. The obtained premix is ​​put into a twin-screw extruder for melt blending, wherein the temperature of zone 1 in the twin-screw extruder is 180°C, the temperature of zone 2 is 200°C, the temperature of zone 3 is 190°C, the temperature of zone 4 is 180°C, the temperature of zone 5 is 170°C, the temperature of the die head is 180°C, and extrusion granulation is performed to obtain a composite material modified polypropylene material.

[0065] The composite fiber modified polypropylene material is prepared through the above steps.

[0066] Comparative Example 2

[0067] This comparative example provides a method for preparing a composite fiber modified polypropylene material, comprising the following steps:

[0068] S1. Weigh by weight, add 60 parts of polypropylene resin, 5 parts of basalt fiber, 3 parts of maleic anhydride grafted polypropylene, 0.5 parts of ethylene bisstearic acid amide, and 0.1 parts of antioxidant 1010 into a mixer and mix them at a mixing temperature of 170° C. for 5 min to obtain a premix;

[0069] S2. The obtained premix is ​​put into a twin-screw extruder for melt blending, wherein the temperature of zone 1 in the twin-screw extruder is 180°C, the temperature of zone 2 is 200°C, the temperature of zone 3 is 190°C, the temperature of zone 4 is 180°C, the temperature of zone 5 is 170°C, the temperature of the die head is 180°C, and extrusion granulation is performed to obtain a composite material modified polypropylene material.

[0070] The composite fiber modified polypropylene material is prepared through the above steps.

[0071] Comparative Example 3

[0072] Compared with Example 1, the only difference is:

[0073] Replace 5 parts of composite fiber with 3 parts of composite fiber.

[0074] Comparative Example 4

[0075] Compared with Example 1, the only difference is:

[0076] Replace 5 parts of composite fiber with 23 parts of composite fiber.

[0077] Comparative Example 5

[0078] Compared with Example 1, the only difference is:

[0079] S3. Weigh by weight, add 45 parts of polypropylene resin, 15 parts of composite fiber, 2 parts of maleic anhydride grafted polypropylene, 1.5 parts of ethylene bisstearamide, and 0.3 parts of antioxidant 1010 into a mixer and mix them at a mixing temperature of 170° C. for 5 minutes to obtain a premix.

[0080] Comparative Example 6

[0081] Compared with Example 1, the only difference is:

[0082] S3. Weigh by weight, add 95 parts of polypropylene resin, 15 parts of composite fiber, 2 parts of maleic anhydride grafted polypropylene, 3 parts of ethylene bisstearamide, and 0.3 parts of antioxidant 1010 into a mixer and mix them at a mixing temperature of 170° C. for 5 minutes to obtain a premix.

[0083] Comparative Example 7

[0084] Compared with Example 1, the only difference is:

[0085] S4. The obtained premix is ​​put into a twin-screw extruder for melt blending, wherein the temperature of zone 1 in the twin-screw extruder is 170°C, the temperature of zone 2 is 190°C, the temperature of zone 3 is 200°C, the temperature of zone 4 is 210°C, the temperature of zone 5 is 220°C, the temperature of the die head is 170°C, and extrusion granulation is performed to obtain a composite material modified polypropylene material.

[0086] The performance tests of the composite modified polypropylene materials obtained in Examples 1 to 8 and Comparative Examples 1 to 7 were carried out: (1) Tensile strength: in accordance with ISO 527. (2) Flexural modulus: in accordance with ISO 178. (3) Heat deformation temperature: in accordance with ISO 75. (4) Scratch resistance test: 20 stripes with a spacing of 2 mm in each orthogonal direction were scratched on the leather grain plate with a load of 10N using a German ERICHSEN cross-cutting instrument. The ΔL value (color change) of the sample surface before and after scratching was measured by a colorimeter to judge its scratch resistance. The smaller the ΔL value, the better the scratch resistance. The test results are shown in Table 1:

[0087] Table 1

[0088]

[0089] It can be seen from Table 1 that, compared with Examples 1 to 8, the mechanical properties, heat deformation resistance and wear resistance of the composite fiber modified polypropylene material prepared in Comparative Examples 1 to 7 are lower than those of the composite fiber modified polypropylene material prepared in Examples 1 to 8. It can be seen that the composite fiber modified polypropylene material prepared in the present invention has good mechanical properties, moisture resistance, heat resistance and corrosion resistance, and is widely used as an engineering plastic in the fields of medical treatment, home appliances, automobiles and aerospace.

[0090] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0091] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A composite fiber modified polypropylene material, characterized in that: By weight, it includes the following raw materials: Polypropylene resin: 50-80 parts; Composite fiber: 5-20 parts; Compatibilizer: 3-5 parts; Lubricant: 0.5-2 parts; Antioxidant: 0.1-0.5 parts; The composite fiber is prepared by the following steps: Add the modified basalt fiber into the hydrochloric acid solution, add xylan, stir for 10-15 minutes, introduce ammonia, condense and reflux at 30-35°C and stir for 20-30 minutes, adjust the pH value to 7.0-7.5, continue stirring and reacting for 6-7 hours, centrifuge and wash, and vacuum dry to obtain composite fiber.

2. A composite fiber modified polypropylene material according to claim 1, characterized in that: The dosage ratio of modified basalt fiber, hydrochloric acid solution and xylan is 1.0-1.2g:50mL:0.50-0.55g.

3. The composite fiber modified polypropylene material according to claim 1, characterized in that: The modified basalt fiber is prepared by the following steps: The basalt fiber was added to deionized water and anhydrous ethanol, ultrasonically dispersed for 30 minutes, and then 3-mercaptopropyltrimethoxysilane was added, the pH was adjusted to 4.0-5.0, the temperature was raised to 80-85°C, stirred for reaction for 1-2 hours, centrifuged for washing, and dried to obtain modified basalt fiber.

4. A composite fiber modified polypropylene material according to claim 3, characterized in that: The usage ratio of basalt fiber, deionized water, anhydrous ethanol and 3-mercaptopropyltrimethoxysilane is 3.0-3.5 g: 45 mL: 5 mL: 2.0-2.3 g.

5. The composite fiber modified polypropylene material according to claim 1, characterized in that: The compatibilizer is at least one of maleic anhydride grafted polypropylene, maleic anhydride grafted ethylene-octene and maleic anhydride grafted ethylene-vinyl acetate.

6. The composite fiber modified polypropylene material according to claim 1, characterized in that: The lubricant is ethylene bis stearamide.

7. The composite fiber modified polypropylene material according to claim 1, characterized in that: The antioxidant is at least one of a hindered phenol antioxidant and a phosphite antioxidant.

8. The method for preparing a composite fiber modified polypropylene material according to claim 1, characterized in that: The following steps are involved: S1. Add basalt fiber to deionized water and anhydrous ethanol, ultrasonically disperse for 30 minutes, then add 3-mercaptopropyltrimethoxysilane, adjust the pH to 4.0-5.0, heat to 80-85°C, stir and react for 1-2 hours, centrifuge and wash, and dry to obtain modified basalt fiber; S2, adding the modified basalt fiber to the hydrochloric acid solution, adding xylan, stirring for 10-15 minutes, introducing ammonia, condensing and refluxing at 30-35°C and stirring for 20-30 minutes, adjusting the pH value to 7.0-7.5, continuing to stir and react for 6-7 hours, centrifugally washing, and vacuum drying to obtain composite fibers; S3, weighing by weight, adding polypropylene resin, composite fiber, compatibilizer, lubricant, and antioxidant into a mixer and mixing to obtain a premix; S4, putting the obtained premix into a twin-screw extruder for melt blending, extruding and granulating to obtain a composite material modified polypropylene material.

9. The method for preparing a composite fiber modified polypropylene material according to claim 8, characterized in that: The mixing temperature in S3 is 170-180°C, and the mixing time is 5-15 minutes.

10. The method for preparing a composite fiber modified polypropylene material according to claim 8, characterized in that: In the S4 twin-screw extruder, the temperature of zone 1 is 180-200°C, the temperature of zone 2 is 200-220°C, the temperature of zone 3 is 190-210°C, the temperature of zone 4 is 180-210°C, the temperature of zone 5 is 170-190°C, and the temperature of the die head is 180-195°C.

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