Recycled polypropylene composite material and preparation method therefor and use thereof

Abstract

Disclosed are a recycled polypropylene composite material, and a preparation method therefor and a use thereof. The recycled polypropylene composite material comprises the following components calculated in parts by weight: 50-90 parts of a recycled polypropylene resin; 5-30 parts of polypropylene resin B; 0.1-0.8 parts of a rheological agent, the EPR content in the polypropylene resin B being not less than 28 wt%; the one-minute half-life temperature of the rheological agent being not higher than 210°C; and the fluorescence intensity of the recycled polypropylene resin at 380 nm-420 nm being 4000-6500. In the present invention, by compounding a rheological agent with a one-minute half-life temperature of not higher than 210°C and a polypropylene resin B with an EPR content of not less than 28 wt% into a recycled polypropylene resin with a specific fluorescence intensity, paint adhesion of the recycled polypropylene composite material can be effectively improved while good mechanical properties are maintained.

Description

A recycled polypropylene composite material, its preparation method and application Technical Field

[0001] This invention relates to the field of polypropylene composite materials technology, and more specifically, to a recycled polypropylene composite material, its preparation method, and its application. Background Technology

[0002] Polypropylene resin is one of the three major general-purpose plastics. Due to its advantages such as wide availability, low cost, low density, and easy molding, it has been widely used in many fields such as home appliances, automobiles, power tools, packaging, building materials, and furniture.

[0003] With increasing environmental awareness and growing resource scarcity, the global trend of "low-carbon economy" has made the recycling of recycled plastics an important research topic. However, recycled polypropylene resin (rPP) is susceptible to degradation by light and heat, oxidation, and other factors during long-term use and recycling, leading to performance degradation. For example, when used on painted parts, it often suffers from problems such as blistering and peeling. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects or shortcomings of recycled polypropylene resin in the prior art, such as blistering and peeling, when used on sprayed parts, and to provide a recycled polypropylene composite material.

[0005] Another object of the present invention is to provide a method for preparing the above-mentioned recycled polypropylene composite material.

[0006] Another object of the present invention is to provide the application of the above-described recycled polypropylene composite material.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A recycled polypropylene composite material comprises the following components in parts by weight:

[0009] 50-90 parts of recycled polypropylene resin;

[0010] Polypropylene resin B5~30 parts;

[0011] 0.1~0.8 parts of rheology modifier;

[0012] The polypropylene resin B contains an EPR content of not less than 28 wt%; the rheology modifier has a half-life temperature of not more than 210°C; and the recycled polypropylene resin has a fluorescence intensity of 4000-6500 at 380 nm to 420 nm.

[0013] In this invention, by adding polypropylene resin B with a specific EPR content and a rheology modifier to recycled polypropylene resin, the polar groups generated during the aging process of the recycled polypropylene resin increase the adhesion sites of paint molecules. Furthermore, the micro-crosslinking of the ethylene segment with the polypropylene resin with the specific EPR content under the action of the rheology modifier increases the exposed area of ​​the ethylene segment on the surface of the composite, which can effectively provide favorable sites and improve the paint adhesion of the recycled polypropylene composite material.

[0014] Specifically, the polar group content of the recycled polypropylene resin is reflected by the degree of aging; the degree of aging of the recycled polypropylene resin is tested by fluorescence spectroscopy. The fluorescence spectrum reflects the degree of aging of the polypropylene molecular chain itself. The longer the emission wavelength, the greater the degree of conjugation of the polypropylene molecular chain (the greater the degree of molecular aging), the higher the fluorescence intensity, and the more conjugated molecular chains (the more aged molecules).

[0015] Furthermore, the fluorescence spectrum emission wavelength of the recycled polypropylene resin is in the range of 380nm to 420nm, and the fluorescence intensity is in the range of 4000 to 6500.

[0016] It should be noted that the content of recycled polypropylene resin in the composite material described in this invention is preferably not less than 40 wt%.

[0017] The recycled polypropylene resin described in this invention exhibits a fluorescence intensity of 4000-6500 nm in the 380 nm to 420 nm range. For example, but not limited to, values ​​of 4000, 4200, 4500, 4800, 5000, 5200, 5500, 5800, 6000, 6200, or 6500 are all acceptable for achieving this invention. Further, the fluorescence intensity is 4200-6300 nm.

[0018] The polypropylene resin B described in this invention has an EPR content of not less than 28 wt%, for example, but not limited to, not less than 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt%, 35 wt%, 36 wt%, 37 wt%, 38 wt%, 39 wt%, 40 wt%, 41 wt%, 42 wt%, 43 wt%, 44 wt%, or 45 wt%, etc., all of which can achieve the present invention.

[0019] Furthermore, the EPR content in the polypropylene resin B is 35wt%~45wt%.

[0020] Specifically, the method for determining the EPR content is gel permeation chromatography.

[0021] It should be noted that the one-minute half-life temperature of the rheology modifier described in this invention is not higher than 210°C. For example, but not limited to, temperatures not higher than 210°C, 205°C, 200°C, 195°C, 190°C, 185°C, 180°C, 175°C, 170°C, or 165°C can all achieve this invention. Further, the one-minute half-life temperature of the rheology modifier is 170~190°C.

[0022] Furthermore, the rheology modifier has a one-minute half-life temperature of 180~184°C.

[0023] Specifically, the method for determining the one-minute half-life temperature of the rheology modifier is an electrochemical method.

[0024] Furthermore, the rheology modifier is an organic peroxide.

[0025] Furthermore, the rheology modifier is tert-butyl peroxide.

[0026] Specifically, the rheology modifier is one or more of di-tert-butyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxide)hexane, and di(tert-butylperoxide isopropyl)benzene.

[0027] It should be noted that the polypropylene resin B mentioned in this invention is 5 to 30 parts, for example, but not limited to 5 parts, 8 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, 28 parts or 30 parts, etc., all of which can achieve this invention.

[0028] The rheology modifier used in this invention is 0.1 to 0.8 parts, for example, but not limited to 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts or 0.8 parts, etc., all of which can achieve the present invention.

[0029] Furthermore, the recycled polypropylene composite material comprises the following components calculated in parts by weight:

[0030] 58-80 parts of recycled polypropylene resin;

[0031] Polypropylene resin B10~25 parts;

[0032] 0.2 to 0.5 parts of rheology modifier.

[0033] Furthermore, the recycled polypropylene composite material comprises the following components in parts by weight:

[0034] 60-65 parts of recycled polypropylene resin;

[0035] 15-20 parts of polypropylene resin B;

[0036] 0.3 to 0.5 parts of rheology modifier.

[0037] Furthermore, the recycled polypropylene resin is obtained by recycling, processing, and granulating waste plastic products from daily life or industry, wherein the EPR content is less than 10 wt%.

[0038] Furthermore, the melt flow rate of the recycled polypropylene resin at 230°C and a load of 2.16 kg is 20~40 g / 10 min.

[0039] Furthermore, the melt flow rate of the polypropylene resin B at 230°C and a load of 2.16 kg is 0.5~40 g / 10 min.

[0040] Specifically, the test standard for the melt flow rate is ISO 1133-1-2022.

[0041] Furthermore, the recycled polypropylene composite material also includes 5-20 parts of filler, 2-10 parts of toughening agent, and 0.1-5 parts of additives.

[0042] Furthermore, the filler includes one or more of talc, calcium carbonate, wollastonite, or mica.

[0043] Furthermore, the toughening agent includes one or more of ethylene-butene copolymer, ethylene-octene copolymer, or hydrogenated styrene-butadiene block copolymer.

[0044] Furthermore, the additives include one or more of black seeds, light stabilizers, or antioxidants.

[0045] Specifically, it includes 0.5 to 2 parts black seed, 0.1 to 0.5 parts light stabilizer, and 0.2 to 1 part antioxidant.

[0046] Furthermore, the black seed is polyvinyl carbon black masterbatch.

[0047] The light stabilizer described in this invention can be a commonly used light stabilizer, such as, but not limited to, hindered amine light stabilizers, benzotriazole light stabilizers, or benzophenone light stabilizers.

[0048] The antioxidants described in this invention can be commonly used antioxidants, such as, but not limited to, hindered phenolic antioxidants and / or phosphite antioxidants.

[0049] Specifically, the hindered phenolic antioxidant is one or more of N,N'-hexamethylene bis(3,5-di-tert-butyl-4-hydroxyphenylpropionamide (Irganox 1098), pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) (Irganox 1010), triethylene glycol bis-3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate (Iragnox 245), octadecyl β-(4-hydroxy-3,5-di-tert-butylphenyl)propionate (Iragnox 1076), or 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)acrylic acid]-1,1-dimethyl}-2,4,8,10-tetraoxaspirocycloundecane] (ADK AO-80).

[0050] The phosphite antioxidant is one or more of tris(2,4-di-tert-butylphenyl) phosphite (Irganox 168), bis(2,6-di-tert-butyl-4-tolyl) pentaerythritol phosphite (PEP-36), or 627A.

[0051] This invention also protects a method for preparing the above-mentioned recycled polypropylene composite material, comprising the following steps:

[0052] The components are mixed evenly, melt-blended and extruded in an extruder to obtain a recycled polypropylene composite material.

[0053] Specifically, the mixture is homogenized using a high-speed mixer for 1-3 minutes at a speed of 1000 rpm.

[0054] Specifically, the extruder is a twin-screw extruder.

[0055] Specifically, the temperature of the twin-screw extruder is 60~120℃ in zone one, 190~220℃ in zones two to four, and 180~220℃ in zones five to ten; the rotational speed of the twin-screw extruder is 300~500 rpm.

[0056] This invention also protects the application of the above-mentioned recycled polypropylene composite material in automotive parts, especially in painted parts, such as automotive bumpers, side skirts, wheel arches, and lower trim panels.

[0057] Compared with the prior art, the beneficial effects of the present invention are:

[0058] This invention provides a recycled polypropylene composite material. By adding polypropylene resin B with an EPR content of not less than 28 wt% and a rheology modifier with a one-minute half-life temperature of not more than 210°C to the recycled polypropylene resin, and adjusting the fluorescence intensity of the recycled polypropylene resin, the paint adhesion of the recycled polypropylene composite material can be effectively improved, and it also has good impact strength. Embodiments of the present invention

[0059] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0060] 1. Raw materials used in each embodiment and comparative example:

[0061] Recycled polypropylene resin:

[0062] Recycled polypropylene resin 1: Recycled polypropylene material for washing machine drums, RPP DCT-1121 PW72(SX), melt flow rate of 35g / 10min at 230℃ and 2.16kg load, emission wavelength of 390nm, fluorescence intensity of 4500, purchased from Chengdu Suxin.

[0063] Recycled polypropylene resin 2: Recycled polypropylene material for washing machine drums, RPP DCM-1124 PN52(GR), melt flow rate of 25g / 10min at 230℃ and 2.16kg load, emission wavelength of 410nm, fluorescence intensity of 6300, purchased from Changhong Gerun.

[0064] Recycled polypropylene resin 3: Recycled polypropylene material for washing machine drums, RPP DCT-1121 PW72(DW), melt flow rate of 38g / 10min at 230℃ and 2.16kg load, emission wavelength of 430nm, fluorescence intensity of 6700, purchased from Jieshou Dongwei.

[0065] Recycled polypropylene resin 4: Recycled polypropylene for washing machine drums, RPP DCT-1121 PW72(GR), melt flow rate of 36 g / 10 min at 230℃ and 2.16 kg load, emission wavelength of 370 nm, fluorescence intensity of 3900, purchased from Changhong Gerun; Polypropylene resin B:

[0066] Polypropylene resin B1: PP NS06, EPR content 45wt%, purchased from Sinopec Korea Petrochemical.

[0067] Polypropylene resin B2: PP LH-KA30, EPR content 40wt%, purchased from Lihe Zhixin;

[0068] Polypropylene resin B3: PP EP246P, EPR content 35wt%, purchased from Basel;

[0069] Polypropylene resin B4: PP SP 179, EPR content 24wt%, purchased from Lanzhou Petrochemical;

[0070] Rheology modifier:

[0071] Rheology modifier 1: bis(tert-butylperoxyisopropyl)benzene, with a one-minute half-life temperature of 182℃, purchased from Shanghai Bojing;

[0072] Rheology modifier 2: di-tert-butyl peroxide, with a one-minute half-life temperature of 186°C, purchased from Aladdin Chemicals;

[0073] Rheology modifier 3: 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, with a one-minute half-life temperature of 179°C, purchased from AkzoNobel;

[0074] Rheology modifier 4: tert-butyl hydroperoxide, with a one-minute half-life temperature of 223°C, purchased from AkzoNobel;

[0075] Filler: Talc powder, TY90-20-A, purchased from Dongguan Sanzhi;

[0076] Toughening agent: Ethylene-butene copolymer, POE ENGAGE 7447, purchased from Dow Chemical.

[0077] Additives:

[0078] Black source: Polyvinyl carbon black masterbatch, PE2718, commercially available;

[0079] Light stabilizer: Hindered amine light stabilizer, commercially available;

[0080] Antioxidants: A compound of hindered phenolic antioxidants and phosphite antioxidants in a 1:1 mass ratio, both of which are commercially available.

[0081] It should be noted that the same raw materials were used in the parallel experiments of the embodiments and comparative examples of the present invention.

[0082] 2. The recycled polypropylene composite materials described in each embodiment and comparative example were prepared according to the formulations in Tables 1-2 using the following methods:

[0083] The components are mixed evenly in a high-speed mixer at a ratio of 1 to 3 minutes and a mixing speed of 1000 rpm. The mixture is then fed into a twin-screw extruder and melt-blended, extruded, and granulated to obtain a recycled polypropylene composite material. The temperature of the first zone of the twin-screw extruder is 90°C, the temperatures of the second to fourth zones are 205°C, and the temperatures of the fifth to tenth zones are 190°C. The rotation speed of the twin-screw extruder is 400 rpm.

[0084] 3. Performance Testing:

[0085] (1) Spraying adhesion test: The recycled polypropylene composite materials prepared in each example and comparative example were sprayed with paint in a square plate of 100mm*100mm*2mm. Before spraying, flame treatment was performed, and after spraying, the plate was baked at 80℃ for 40min to cure.

[0086] a. Water Boiling Test: The treated sample is placed in a 40℃ constant temperature water bath and soaked for 240 hours. The surface blistering is observed, and the presence and size of the bubbles are used to evaluate the adhesion quality. The more and larger the bubbles, the worse the adhesion. The evaluation levels are divided into: none, bubbles, mild prickly heat, and severe prickly heat. "None" means no blistering; "blistering" means bubbles with a diameter ≥ 0.1 mm; "bubble formation" means bubbles with a diameter < 0.1 mm and a density < 0.1 mm per unit area (1 cm²). 2 The number of small prickly heat bumps is less than 10, indicating mild prickly heat; the diameter of the surface bubbles is less than 0.1 mm, and the area per unit area (1 cm²) is less than 10 mm. 2 A condition characterized by ≥10 small prickly heat rashes is considered severe.

[0087] b. Cross-cut test: The treated samples were tested according to GB / T 9286-2021 standard. Specifically: 5B is defined as follows: smooth crisscross edges with no paint peeling at the edges and intersections; 4B is defined as small areas of paint peeling at the intersections with a total peeling area of ​​less than 5%; 3B is defined as small areas of paint peeling at the edges and intersections with a total peeling area between 5% and 15%; 2B is defined as large areas of paint peeling at the edges and intersections with a total peeling area between 15% and 35%; 1B is defined as large areas of paint peeling at the edges and intersections with a total peeling area between 35% and 65%; and 0B is defined as areas with peeling exceeding the 1B standard.

[0088] (2) Cantilever beam notched impact strength (23℃) test: The polypropylene composite materials prepared in each example and comparative example were tested according to ISO 180-2023 standard.

[0089] Examples 1-15 and Comparative Examples 1-5

[0090] Table 1. Amounts (parts by weight) and properties of each component in the recycled polypropylene composites of Examples 1-9

[0091]

[0092] Table 2. Amounts (parts by weight) and properties of each component in the recycled polypropylene composites of Examples 10-15 and Comparative Examples 1-5

[0093]

[0094] The recycled polypropylene composite material prepared in this invention exhibits good paint adhesion and impact strength. Specifically, after painting and a boiling water test, it shows only slight blistering or no bubbles; its cross-cut adhesion test yields a value of at least 4B, and its impact strength is at least 20 KJ / m. 2 .

[0095] As can be seen from Comparative Example 1, even if the EPR content in the added polypropylene resin B is adjusted, the paint adhesion of the resulting recycled polypropylene composite material is still poor without the addition of rheology modifier.

[0096] As can be seen from Comparative Example 2, if the EPR content in the added polypropylene resin B is too low, even with the addition of a specific rheology modifier, the resulting recycled polypropylene composite material has poor paint adhesion and a significant decrease in impact strength.

[0097] As can be seen from Comparative Example 3, if the temperature of the one-minute half-life of the rheology modifier used is too high, the paint adhesion of the resulting recycled polypropylene composite material will decrease significantly.

[0098] As can be seen from Comparative Examples 4 and 5, if the fluorescence intensity of the recycled polypropylene resin used is too low or too high, the overall performance of the resulting recycled polypropylene composite material will decrease significantly.

[0099] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. 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 claims of the present invention.

Claims

1. A recycled polypropylene composite material, characterized in that, Includes the following components, calculated in parts by weight: 50-90 parts of recycled polypropylene resin; Polypropylene resin B5~30 parts; 0.1~0.8 parts of rheology modifier; The polypropylene resin B contains an EPR content of not less than 28 wt%; the rheology modifier has a half-life temperature of not more than 210°C; and the recycled polypropylene resin has a fluorescence intensity of 4000-6500 at 380 nm to 420 nm.

2. The recycled polypropylene composite material according to claim 1, characterized in that, The EPR content in the polypropylene resin B is 35wt%~45wt%.

3. The recycled polypropylene composite material according to claim 1, characterized in that, The rheology modifier is an organic peroxide; the one-minute half-life temperature of the rheology modifier is 170~190℃.

4. The recycled polypropylene composite material according to claim 1, characterized in that, The recycled polypropylene resin has an EPR content of less than 10 wt%.

5. The recycled polypropylene composite material according to claim 1, characterized in that, It also includes 5 to 20 parts filler, 2 to 10 parts toughening agent, and 0.1 to 5 parts additives.

6. The recycled polypropylene composite material according to claim 5, characterized in that, The filler includes one or more of talc, calcium carbonate, wollastonite, or mica.

7. The recycled polypropylene composite material according to claim 5, characterized in that, The toughening agent includes one or more of ethylene-butene copolymer, ethylene-octene copolymer, or hydrogenated styrene-butadiene block copolymer.

8. The recycled polypropylene composite material according to claim 5, characterized in that, The additives include one or more of black seeds, light stabilizers, or antioxidants.

9. A method for preparing the recycled polypropylene composite material according to any one of claims 1 to 8, characterized in that, Includes the following steps: The components are mixed evenly, melt-blended and extruded in an extruder to obtain a recycled polypropylene composite material.

10. The use of the recycled polypropylene composite material according to any one of claims 1 to 8 in the preparation of automotive parts.

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