A modified PP composite material with high toughness and low warpage, and its preparation method and application

Abstract

This invention discloses a high-toughness, low-warpage modified PP composite material, its preparation method, and its applications. The modified PP composite material, by weight, comprises 45-80 parts PP resin, 10-30 parts sepiolite powder, 3-8 parts compatibilizer, 3-20 parts toughening agent, 0.1-0.5 parts antioxidant, and 0.1-0.5 parts lubricant; wherein the toughening agent is POE grafted with butyl methacrylate. The modified PP composite material obtained by this invention exhibits excellent impact performance and low warpage characteristics, solving the problem that improving the toughness of PP materials often exacerbates warpage in existing technologies. Furthermore, by using PP-g-BMA as a compatibilizer, a low odor level can be achieved.

Description

Technical Field

[0001] This invention relates to the field of polymer material processing technology, and in particular to a modified PP composite material with high toughness and low warpage, its preparation method, and its application. Background Technology

[0002] Polypropylene (PP), one of the five major general-purpose plastics, boasts advantages such as low cost, low density, ease of processing, and good mechanical properties. With its expanding applications, it has been used in hardware tools, home appliances, automobiles, and other fields. However, polypropylene resin also has some drawbacks, such as high shrinkage, warping, low toughness, susceptibility to aging, sensitivity to light and heat, and relatively low impact strength at low temperatures. These limitations restrict its further application.

[0003] Existing patents contain numerous solutions for modifying high-toughness PP composites. However, while improving the toughness of PP materials, changes in their internal structural components often exacerbate warping. In practical applications, such as refrigerator interior panels and woodworking table saws, high impact toughness and low warping are often required simultaneously. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the present invention aims to provide a modified PP composite material with high toughness and low warpage. The modified PP composite material uses PP resin as the base material, is compounded with a certain proportion of sepiolite powder, and is toughened by butyl methacrylate grafted polyolefin elastomer (hereinafter referred to as POE-g-BMA). The resulting modified PP composite material has excellent impact performance and low warpage characteristics.

[0005] Another objective of this invention is to provide a method for preparing a modified PP composite material with high toughness and low warpage.

[0006] Another object of the present invention is to provide an application of a modified PP composite material with high toughness and low warpage.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] This invention provides a modified PP composite material with high toughness and low warpage, comprising, by weight, 45-80 parts PP resin, 10-30 parts sepiolite powder, 3-8 parts compatibilizer, 3-20 parts toughening agent, 0.1-0.5 parts antioxidant, and 0.1-0.5 parts lubricant; wherein the toughening agent is a polyolefin elastomer (POE-g-BMA) grafted with butyl methacrylate, and the grafting rate of butyl methacrylate (BMA) is between 0.8% and 1.2%.

[0009] In some embodiments, POE-g-BMA is prepared by the following method: BMA and POE are extruded in a twin-screw extruder using a melt grafting method to obtain POE-g-BMA.

[0010] In some embodiments, the compatibilizer is polypropylene (PP-g-BMA) grafted with butyl methacrylate, wherein the grafting rate of butyl methacrylate (BMA) is between 0.6% and 1.2%.

[0011] In some embodiments, PP-g-BMA is prepared by the following method: BMA and PP are extruded in a twin-screw extruder using a melt grafting method to obtain PP-g-BMA.

[0012] In some embodiments, the antioxidant is a combination of hindered phenolic antioxidants, sulfur ester auxiliary antioxidants, and hindered amine antioxidants, with a mass ratio of 0.5-1.5:1.5-2.5:0.5-1.5.

[0013] In some embodiments, the lubricant is erucamide.

[0014] In some embodiments, the PP resin is an isotacticity ≥98%, a crystallinity ≥70%, and a melt index of 1-30 g / 10 min at a temperature of 230°C and a test load of 2.16 kg.

[0015] In some embodiments, the sepiolite powder has a mass fraction of 15-25% in the modified PP composite material.

[0016] In some embodiments, the toughening agent has a mass fraction of 10-15% in the modified PP composite material.

[0017] This invention also provides a method for preparing the aforementioned high-toughness, low-warpage modified PP composite material, comprising the following steps:

[0018] (1) Weigh out the PP resin, sepiolite powder, compatibilizer, toughening agent, antioxidant and lubricant according to the weight parts, and set aside;

[0019] (2) Add PP resin to the mixer, then add compatibilizer, toughening agent, antioxidant and lubricant, and stir evenly at room temperature;

[0020] (3) The material mixed in step (2) is placed in a co-rotating twin-screw extruder, and after melting, plasticizing, extrusion, cooling and pelletizing, a modified PP composite material with high toughness and low warpage is obtained.

[0021] In some embodiments, the melting and plasticizing temperature is set as follows: first stage 170℃-190℃, second stage 180℃-200℃, third stage 185℃-210℃, fourth stage 185℃-210℃, fifth stage 170℃-200℃, sixth stage 170℃-200℃, seventh stage 170℃-200℃, eighth stage 170℃-200℃, ninth stage 180℃-200℃, tenth stage 180℃-200℃, melt temperature 180℃-220℃, and die head temperature 200℃-220℃.

[0022] In some embodiments, the screw diameter of the co-rotating twin-screw extruder is 40-65 mm, and the length-to-diameter ratio of the screw is 40:1.

[0023] The present invention also provides the application of the aforementioned high-toughness, low-warpage modified PP composite material for the manufacture of automotive fans and automotive interior parts.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] (1) The modified PP material of the present invention uses sepiolite powder-filled modified PP resin to modify PP material and POE-g-BMA as compatibilizer. POE grafted with BMA can be well compatible with sepiolite, which reduces the crystallinity of PP but refines the PP grains. At the same time, its high elasticity also greatly improves the toughness of the material. The layered chain structure of sepiolite powder can play a good supporting role in the composite system, making the composite material have better anti-warping performance. At the same time, there are huge nanopores inside, which can play a good buffering role when the composite material is impacted. This solves the problem that improving the toughness of PP material in the prior art often aggravates the warping of the material.

[0026] (2) The modified PP material of the present invention uses PP-g-BMA as a compatibilizer. Its BMA segment has a strong limit and can be well combined with sepiolite powder, which greatly improves the compatibility between PP material and sepiolite powder. At the same time, because the BMA group has better stability than the maleic anhydride (MAH) group, less monomer flows out during extrusion and injection molding, thus effectively avoiding the generation of odor and achieving a lower odor level.

[0027] (3) The modified PP material of the present invention has high toughness, good flatness, and low odor. In practical applications, it has excellent dimensional stability and impact resistance, and is highly adaptable to use in tool industry, automotive interior parts, and automotive fan parts. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. It should be understood that the following description is merely illustrative and not intended to limit the invention.

[0029] The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0030] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1 to 5” is disclosed, the described range should be interpreted as including the ranges “1 to 4”, “1 to 3”, “1 to 2”, “1 to 2 and 4 to 5”, “1 to 3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0031] The indefinite articles “a” and “an” preceding an element or component of this invention do not impose any limitation on the quantity (i.e., number of times) of the element or component. Therefore, “an” or “a” should be interpreted as including one or at least one, and the singular form of an element or component also includes the plural form, unless the quantity clearly refers only to the singular form.

[0032] Furthermore, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., described below refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms are not necessarily directed at the same embodiment or example. Moreover, the technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0033] Example

[0034] A high-toughness, low-warpage, and low-odor modified PP composite material comprises the following components by weight:

[0035]

[0036] The specific materials to be added and their weight proportions are as shown in Table 1.

[0037] The PP resin is an isotacticity ≥98%, crystallinity ≥70%, and a melt index of 1-30 g / 10 min at 230℃ and a test load of 2.16 kg. Preferably, the PP resin has a melt index of 2-5 g / 10 min at 230℃ and a test load of 2.16 kg. The sepiolite powder is a hydrous magnesium silicate clay mineral with a layered chain structure, Mg8(H2O)4[Si6O16]2(OH)4·8H2O, wherein the SiO2 content is generally between 54% and 60%, and the MgO content is mostly in the range of 21% to 25%. Preferably, the mass fraction of the sepiolite powder in the PP composite material is 15-25%. The compatibilizer is a methacrylate-coated butadiene oxide... The ester-grafted modified polypropylene (PP-g-BMA) is prepared by melt grafting on a twin-screw extruder using a melt grafting method to extrude BMA and PP in a specific ratio, with a BMA grafting rate between 0.8% and 1.2%. The toughening agent is POE (POE-g-BMA) modified with butyl methacrylate grafting. In this embodiment, BMA and POE are also extruded on a twin-screw extruder using a melt grafting method to prepare the corresponding grafted product, with a BMA grafting rate between 0.6% and 1.2%. The antioxidant is a combination of hindered phenolic antioxidant 1010, sulfurized ester auxiliary antioxidant 412s, and hindered amine antioxidant HS-234, with a mass ratio of 1:2:1. The lubricant is erucamide.

[0038] The materials of Examples 1-4 and Comparative Examples 1-5 were prepared according to the following method:

[0039] (1) Add PP resin to a high-speed mixer, then add compatibilizer, toughening agent, sepiolite powder, antioxidant and lubricant, and stir evenly at room temperature (the specific materials added and their weight parts are based on Table 1).

[0040] (2) The mixed materials are placed in a co-rotating twin-screw extruder, and after melting, plasticizing, extrusion, cooling and pelletizing, a high-toughness, low-warpage modified PP composite material is obtained.

[0041] The co-rotating twin-screw extruder used in the above method can have a screw diameter of 40-65mm and a length-to-diameter ratio of 40:1. The melt plasticizing temperature is set as follows: first stage 170℃-190℃, second stage 180℃-200℃, third stage 185℃-210℃, fourth stage 185℃-210℃, fifth stage 170℃-200℃, sixth stage 170℃-200℃, seventh stage 170℃-200℃, eighth stage 170℃-200℃, ninth stage 180℃-200℃, tenth stage 180℃-200℃, melt temperature 180℃-220℃, and die temperature 200℃-220℃. Within these parameter ranges, the properties of the prepared material are almost identical.

[0042] Table 1. Specific material formulations for Examples 1-4 and Comparative Examples 1-5 (in kilograms)

[0043]

[0044] The PP composite materials obtained in the examples and comparative examples were dried in an oven at 120°C and then injection molded to produce sample pieces. The injection molding temperatures were as follows:

[0045] Feeding section: 200℃; Second section: 205℃; Third section: 205℃; Nozzle: 210℃.

[0046] Finally, the injection-molded samples were placed in a desiccator for conditioning: the conditioning temperature was 23℃ and the conditioning time was 24h; the performance test results of the materials of each embodiment and comparative example are shown in Table 2 below.

[0047] Table 2. Material performance test results for each embodiment and comparative example.

[0048]

[0049]

[0050] Note: ★★★ indicates the highest level of evenness, and ★ indicates the lowest level of flatness.

[0051] The performance test results of Example 3 and Comparative Examples 1-3 show that: sepiolite exhibits similar tensile strength and flexural modulus to talc in the composite material system, but demonstrates superior impact strength and smoothness. Compared to calcium carbonate, sepiolite exhibits similar impact performance in the composite material system, but demonstrates superior rigidity and smoothness. Compared to mica powder, sepiolite exhibits similar smoothness characteristics in the composite material system, but its impact strength is far superior to that of mica powder. This is because the layered chain structure of sepiolite provides excellent support in the composite system, giving the composite material superior anti-warping properties. Simultaneously, the presence of large nanopores within sepiolite provides excellent cushioning when the composite material is subjected to impact.

[0052] The performance test results of Example 3 and Comparative Example 4 show that Example 3 with added compatibilizer PP-g-BMA exhibits superior physical properties, especially with a significant improvement in impact strength and better flatness. This is because its BMA segment has a strong limit and can combine well with sepiolite powder, greatly improving the compatibility between PP material and sepiolite powder.

[0053] The performance test results of Examples 1-4 and Comparative Examples 1-5 show that the odor level of the test groups with compatibilizers PP-g-BMA and POE-g-BMA can reach 2.7, while Comparative Example 5 with PP-g-MAH and POE-g-MAH can only reach 3.5. This is because the BMA group has better stability than the MAH group, and less monomer flows out during extrusion and injection molding, thus effectively avoiding the generation of odor and achieving a lower odor level.

[0054] The performance test results of Examples 1-4 show that: preferably, the mass fraction of sepiolite powder in the modified PP composite material is 15-25%, and preferably, the mass fraction of toughening agent POE-g-BMA in the modified PP composite material is 10-15%.

[0055] Those skilled in the art will readily understand that the above description is merely an embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A modified PP composite material with high toughness and low warpage, characterized in that, By weight, it contains 45-80 parts PP resin, 10-30 parts sepiolite powder, 3-8 parts compatibilizer, 3-20 parts toughening agent, 0.1-0.5 parts antioxidant, and 0.1-0.5 parts lubricant; wherein the toughening agent is a polyolefin elastomer grafted with butyl methacrylate, and the grafting rate of butyl methacrylate is between 0.8-1.2%; The compatibilizer is polypropylene grafted with butyl methacrylate, and the grafting rate of butyl methacrylate is between 0.6% and 1.2%.

2. The high-toughness, low-warpage modified PP composite material according to claim 1, characterized in that, The antioxidant is a combination of hindered phenolic antioxidants, sulfur ester auxiliary antioxidants, and hindered amine antioxidants, with a mass ratio of 0.5-1.5:1.5-2.5:0.5-1.

5.

3. The high-toughness, low-warpage modified PP composite material according to claim 1, characterized in that, The lubricant is erucamide.

4. The high-toughness, low-warpage modified PP composite material according to claim 1, characterized in that, The PP resin is an isotacticity ≥98%, a crystallinity ≥70%, and a melt index of 1-30 g / 10 min at a temperature of 230℃ and a test load of 2.16 kg.

5. The high-toughness, low-warpage modified PP composite material according to claim 1, characterized in that, The sepiolite powder has a mass fraction of 15-25% in the modified PP composite material.

6. The high-toughness, low-warpage modified PP composite material according to claim 1, characterized in that, The toughening agent has a mass fraction of 10-15% in the modified PP composite material.

7. The method for preparing the high-toughness, low-warpage modified PP composite material according to any one of claims 1 to 6, characterized in that, Includes the following steps: (1) Weigh out the PP resin, sepiolite powder, compatibilizer, toughening agent, antioxidant and lubricant according to the weight parts, and set aside; (2) Add PP resin to the mixer, then add compatibilizer, toughening agent, antioxidant and lubricant, and stir evenly at room temperature; (3) The material mixed in step (2) is placed in a co-rotating twin-screw extruder, and after melting, plasticizing, extrusion, cooling and pelletizing, a modified PP composite material with high toughness and low warpage is obtained.

8. The preparation method according to claim 7, characterized in that, The melting and plasticizing temperatures are set as follows: first stage 170℃-190℃, second stage 180℃-200℃, third stage 185℃-210℃, fourth stage 185℃-210℃, fifth stage 170℃-200℃, sixth stage 170℃-200℃, seventh stage 170℃-200℃, eighth stage 170℃-200℃, ninth stage 180℃-200℃, tenth stage 180℃-200℃, melt temperature 180℃-220℃, and die head temperature 200℃-220℃.

9. The application of the high-toughness, low-warpage modified PP composite material according to any one of claims 1 to 6, characterized in that, Used to manufacture automotive fans and automotive interior parts.

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