Regenerated polypropylene composite material as well as preparation method and application thereof

Abstract

The invention discloses a regenerated polypropylene composite material as well as a preparation method and application thereof. The regenerated polypropylene composite material comprises the following components in parts by weight: 50-90 parts of regenerated polypropylene resin; 5-30 parts of polypropylene resin B; 0.1 to 0.8 part of a rheological agent; wherein the EPR content in the polypropylene resin B is not less than 28wt%; the one-minute half-life period temperature of the rheological agent is not higher than 210 DEG C; the fluorescence intensity of the regenerated polypropylene resin at 380 nm to 420 nm is 4,000 to 6,500. The rheological agent with the one-minute half-life period temperature not higher than 210 DEG C and the polypropylene resin B with the EPR content not lower than 28 wt% are added into the regenerated polypropylene resin with the specific fluorescence intensity for compounding, the paint adhesive force of the regenerated polypropylene composite material can be effectively improved, and the mechanical property is good.

Description

Technical Field

[0001] The present invention relates to the technical field of polypropylene composite materials, and more specifically, to a recycled polypropylene composite material and a preparation method and application thereof. Background Art

[0002] Polypropylene resin is one of the three major general-purpose plastics. Due to its wide source, 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 the increasing awareness of environmental protection and the increasing scarcity of resources, the "low-carbon economy" trend has been set off worldwide, and the recycling of recycled plastics has become an important research topic. However, recycled polypropylene resin (rPP) is susceptible to factors such as light, heat degradation, and oxidation during long-term use and recycling, resulting in performance degradation. For example, when used on spray-painted parts, there are often problems such as bubbling and shedding. Summary of the invention

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

[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 an application of the above-mentioned recycled polypropylene composite material.

[0007] To achieve the above object, the present invention is implemented through the following technical solutions:

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

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

[0010] Polypropylene resin B 5-30 parts;

[0011] Rheological agent 0.1-0.8 parts;

[0012] The EPR content of the polypropylene resin B is not less than 28 wt %; the one-minute half-life temperature of the rheological agent is not higher than 210° C.; and the fluorescence intensity of the regenerated polypropylene resin at 380 nm to 420 nm is 4000 to 6500.

[0013] In the present invention, by adding a polypropylene resin B with a specific EPR content and a rheological agent to the recycled polypropylene resin, the polar groups generated during the aging process of the recycled polypropylene resin are used to increase the adhesion sites of the paint molecules, and the micro-crosslinking effect of the ethylene segments of the polypropylene resin with a specific EPR content under the action of the rheological agent increases the exposed area of ​​the ethylene segments 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 using fluorescence spectroscopy, and 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), and the higher the fluorescence intensity, the more conjugated molecular chains there are (the more aged molecules there are).

[0015] Furthermore, the fluorescence spectrum emission wavelength of the regenerated polypropylene resin is between 380nm and 420nm, and the fluorescence intensity is between 4000 and 6500.

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

[0017] The fluorescence intensity of the recycled polypropylene resin at 380nm to 420nm is 4000 to 6500, for example but not limited to 4000, 4200, 4500, 4800, 5000, 5200, 5500, 5800, 6000, 6200 or 6500, etc., which can realize the present invention. Further, the fluorescence intensity is 4200 to 6300.

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

[0019] Specifically, the EPR content is determined by gel permeation chromatography.

[0020] It should be noted that the one-minute half-life temperature of the rheological agent in the present invention is not higher than 210°C, for example but not limited to not higher than 210°C, 205°C, 200°C, 195°C, 190°C, 185°C, 180°C, 175°C, 170°C or 165°C, etc. can all achieve the present invention. Further, the one-minute half-life temperature of the rheological agent is 170-190°C.

[0021] Furthermore, the one-minute half-life temperature of the rheological agent is 180-184°C.

[0022] Specifically, the one-minute half-life temperature determination method of the rheological agent is an electrochemical method.

[0023] Furthermore, the rheological agent is an organic peroxide.

[0024] Furthermore, the rheological agent is tert-butyl peroxide.

[0025] Specifically, the rheological agent is one or more of di-tert-butyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and di(tert-butylperoxyisopropyl)benzene.

[0026] It should be noted that the polypropylene resin B in the present 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. can all achieve the present invention.

[0027] The rheological agent in the present 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. can all achieve the present invention.

[0028] Furthermore, the recycled polypropylene composite material comprises the following components calculated in parts by weight:

[0029] 58-80 parts of recycled polypropylene resin;

[0030] Polypropylene resin B 10-25 parts;

[0031] Rheological agent 0.2-0.5 parts.

[0032] Furthermore, the recycled polypropylene composite material comprises the following components calculated in parts by weight:

[0033] 60-65 parts of recycled polypropylene resin;

[0034] Polypropylene resin B 15-20 parts;

[0035] Rheological agent 0.3-0.5 parts.

[0036] Furthermore, the recycled polypropylene resin is obtained by recycling, processing and granulating waste plastic products in life or industry, wherein the EPR content is less than 10wt%.

[0037] Furthermore, the melt flow rate of the recycled polypropylene resin at 230° C. and 2.16 kg load is 20 to 40 g / 10 min.

[0038] Furthermore, the melt flow rate of the polypropylene resin B at 230° C. and a load of 2.16 kg is 0.5 to 40 g / 10 min.

[0039] Specifically, the test standard of the melt flow rate is ISO 1133-1-2022.

[0040] Furthermore, the recycled polypropylene composite material also includes 5 to 20 parts of filler, 2 to 10 parts of toughening agent, and 0.1 to 5 parts of auxiliary agent.

[0041] Furthermore, the filler includes one or more of talc, calcium carbonate, wollastonite or mica.

[0042] Furthermore, the toughening agent includes one or more of ethylene-butene copolymer, ethylene-octene copolymer or hydrogenated styrene-butadiene block copolymer.

[0043] Furthermore, the auxiliary agent includes one or more of black seed, light stabilizer or antioxidant.

[0044] Specifically, it includes 0.5 to 2 parts of black seed, 0.1 to 0.5 parts of light stabilizer, and 0.2 to 1 parts of antioxidant.

[0045] Furthermore, the black seed is a polyethylene-based carbon black masterbatch.

[0046] The light stabilizer in the present invention can be selected from commonly used light stabilizers, such as but not limited to hindered amine light stabilizers, benzotriazole light stabilizers or benzophenone light stabilizers.

[0047] The antioxidant described in the present invention can be selected from commonly used antioxidants, such as but not limited to hindered phenol antioxidants and / or phosphite antioxidants.

[0048] Specifically, the hindered phenol antioxidant is one or more of N,N'-hexamethylenebis(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), β-(4-hydroxy-3,5-di-tert-butylphenyl)propionic acid n-octadecyl (Iragnox 1076) or 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)acrylate]-1,1-dimethyl}-2,4,8,10-tetraoxaspirocycloundecane] (ADK AO-80).

[0049] 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.

[0050] The present invention also provides a method for preparing the above-mentioned recycled polypropylene composite material, comprising the following steps:

[0051] The components are mixed evenly, melt-blended and extruded into granules in an extruder to obtain a recycled polypropylene composite material.

[0052] Specifically, the mixture is mixed evenly by a high-speed mixer, the mixing time is 1 to 3 minutes, and the mixing speed is 1000 rpm.

[0053] Specifically, the extruder is a twin-screw extruder.

[0054] Specifically, the temperature of zone 1 of the twin-screw extruder is 60-120° C., the temperature of zones 2 to 4 is 190-220° C., and the temperature of zones 5 to 10 is 180-220° C.; the rotation speed of the twin-screw extruder is 300-500 rpm.

[0055] The present invention also protects the use of the above-mentioned recycled polypropylene composite material in automobile accessories, especially in spray-painted parts, such as automobile bumpers, automobile side skirts, wheel eyebrows, lower trims and other materials.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] The present invention provides a recycled polypropylene composite material. By adding a polypropylene resin B with an EPR content of not less than 28wt% and a rheological agent with a one-minute half-life temperature of not more than 210°C into 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 the composite material has good impact strength. DETAILED DESCRIPTION

[0058] The present invention is further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0059] 1. Raw materials used in each embodiment and comparative example:

[0060] Recycled polypropylene resin:

[0061] Recycled polypropylene resin 1: washing machine barrel polypropylene recycled material, RPP DCT-1121PW72 (SX), melt flow rate of 35 g / 10 min at 230 ° C and 2.16 kg load, emission wavelength of 390 nm, fluorescence intensity of 4500, purchased from Chengdu Suxin;

[0062] Recycled polypropylene resin 2: washing machine barrel polypropylene recycled material, RPP DCM-1124PN52 (GR), melt flow rate at 230°C, 2.16 kg load is 25 g / 10 min, emission wavelength is 410 nm, fluorescence intensity is 6300, purchased from Changhong Gerun;

[0063] Recycled polypropylene resin 3: washing machine barrel polypropylene recycled material, RPP DCT-1121PW72 (DW), melt flow rate at 230 ° C, 2.16 kg load is 38 g / 10 min, emission wavelength is 430 nm, fluorescence intensity is 6700, purchased from Jieshou Dongwei;

[0064] Recycled polypropylene resin 4: washing machine barrel polypropylene recycled material, RPP DCT-1121PW72 (GR), melt flow rate at 230°C, 2.16kg load is 36g / 10min, emission wavelength is 370nm, fluorescence intensity is 3900, purchased from Changhong Gerun; Polypropylene resin B:

[0065] Polypropylene resin B1: PP NS06, EPR content 45wt%, purchased from Sino-Korea Petrochemical;

[0066] Polypropylene resin B2: PP LH-KA30, EPR content 40wt%, purchased from Lihe Zhixin;

[0067] Polypropylene resin B3: PP EP246P, EPR content 35 wt%, purchased from Basel;

[0068] Polypropylene resin B4: PP SP 179, EPR content 24 wt%, purchased from Lanzhou Petrochemical;

[0069] Rheological agent:

[0070] Rheological agent 1: di(tert-butylperoxide isopropyl)benzene, one-minute half-life temperature is 182°C, purchased from Shanghai Bojing Rheological agent 2: di-tert-butyl peroxide, one-minute half-life temperature is 186°C, purchased from Aladdin Chemical;

[0071] Rheological agent 3: 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, one-minute half-life temperature of 179°C, purchased from Akzo Nobel;

[0072] Rheological agent 4: tert-butyl hydroperoxide, one-minute half-life temperature of 223°C, purchased from Akzo Nobel;

[0073] Filler: talcum powder, TY90-20-A, purchased from Dongguan Sanzhi;

[0074] Toughener: ethylene-butene copolymer, POE ENGAGE 7447, purchased from Dow Chemical;

[0075] Additives:

[0076] Black seed: polyethylene-based carbon black masterbatch, PE2718, commercially available;

[0077] Light stabilizer: hindered amine light stabilizer, commercially available;

[0078] Antioxidant: A mixture of hindered phenol antioxidant and phosphite antioxidant in a mass ratio of 1:1, both of which are commercially available.

[0079] It should be noted that the raw materials used in the parallel experiments of the embodiments of the present invention and the comparative examples are of the same source.

[0080] 2. The recycled polypropylene composite materials described in each embodiment and comparative example were prepared according to the formulations in Tables 1 to 2 by the following method:

[0081] The components are put into a high-speed mixer in proportion and mixed evenly, the mixing time is 1 to 3 minutes, the mixing speed is 1000 rpm, and the components are fed into a twin-screw extruder to obtain a recycled polypropylene composite material through melt blending and extrusion granulation; wherein the temperature of zone 1 of the twin-screw extruder is 90° C., the temperature of zones 2 to 4 is 205° C., the temperature of zones 5 to 10 is 190° C., and the speed of the twin-screw extruder is 400 rpm.

[0082] 3. Performance test:

[0083] (1) Spraying adhesion test: The recycled polypropylene composite material prepared in each embodiment and comparative example was sprayed on a 100 mm*100 mm*2 mm square plate, flame treated before spraying, and baked at 80°C for 40 min for curing after spraying;

[0084] a. Boiling test: Place the treated sample in a 40℃ constant temperature water bath for 240 hours, observe the surface bubbling, and evaluate the adhesion quality based on the presence and size of bubbles. The more and larger the bubbles, the worse the adhesion effect. The evaluation levels are divided into: none, bubbles, mild prickly heat, and severe prickly heat. No bubbles on the surface are considered none; bubbles with a diameter of ≥0.1mm are considered bubbles; bubbles with a diameter of <0.1mm and a unit area (1cm 2 ) The number of small prickly heat rash is less than 10, which is a mild prickly heat rash; the diameter of the bubble on the surface is less than 0.1mm, and the unit area (1cm 2 ) If the number of small prickly heat rashes is ≥10, it is considered severe small prickly heat rashes;

[0085] b. Cross-cut test: The treated samples are tested according to GB / T 9286-2021. Specifically, if the edges of the cross-cuts are smooth and there is no paint falling off at the edges and intersections of the cross-cuts, it is 5B; if there are small pieces of paint falling off at the intersections of the cross-cuts, and the total falling area is less than 5%, it is 4B; if there are small pieces of paint falling off at the edges and intersections of the cross-cuts, and the total falling area is between 5% and 15%, it is 3B; if there are large pieces of paint falling off at the edges and intersections of the cross-cuts, and the total falling area is between 15% and 35%, it is 2B; if there are large pieces of paint falling off at the edges and intersections of the cross-cuts, and the total falling area is between 35% and 65%, it is 1B; if the falling area exceeds the 1B standard, it is 0B;

[0086] (2) Izod notched impact strength (23° C.) test: The polypropylene composite materials prepared in each embodiment and comparative example were tested according to ISO 180-2023 standard.

[0087] Examples 1 to 15 and Comparative Examples 1 to 5

[0088] Table 1 Amount (unit: weight parts) and properties of each component in the recycled polypropylene composite material in Examples 1 to 9

[0089]

[0090]

[0091] Table 2 Amount (unit: weight parts) and properties of each component in the recycled polypropylene composite material in Examples 10 to 15 and Comparative Examples 1 to 5

[0092]

[0093]

[0094] The recycled polypropylene composite material prepared in the present invention has good paint adhesion and impact strength. Specifically, after spraying paint, only slight small prickly heat or no bubbles are produced after boiling test; the cross-cut test is not less than 4B, and the impact strength is not less than 20KJ / m 2 .

[0095] It can be seen from Comparative Example 1 that if no rheological agent is added, even if the EPR content in the added polypropylene resin B is adjusted, the paint adhesion of the obtained recycled polypropylene composite material is poor.

[0096] It can be seen from Comparative Example 2 that if the EPR content in the added polypropylene resin B is too low, even if a specific rheological agent is added, the paint adhesion of the obtained recycled polypropylene composite material is poor and the impact strength is significantly reduced.

[0097] It can be seen from Comparative Example 3 that if the one-minute half-life temperature of the rheological agent used is too high, the paint adhesion of the obtained recycled polypropylene composite material is significantly reduced.

[0098] It can be seen from Comparative Examples 4 and 5 that if the fluorescence intensity of the recycled polypropylene resin used is too low or too high, the comprehensive performance of the obtained recycled polypropylene composite material is significantly reduced.

[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 embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A recycled polypropylene composite material, characterized in that: The composition comprises the following components calculated by weight: 50-90 parts of recycled polypropylene resin; Polypropylene resin B 5-30 parts; Rheological agent 0.1-0.8 parts; The EPR content of the polypropylene resin B is not less than 28 wt %; the one-minute half-life temperature of the rheological agent is not higher than 210° C.; and the fluorescence intensity of the regenerated polypropylene resin at 380 nm to 420 nm is 4000 to 6500.

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

3. The recycled polypropylene composite material according to claim 1, characterized in that: The rheological agent is an organic peroxide; the one-minute half-life temperature of the rheological agent is 170-190°C.

4. The recycled polypropylene composite material according to claim 1, characterized in that: The EPR content in the recycled polypropylene resin is less than 10 wt %.

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

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 auxiliary agent includes one or more of black seed, light stabilizer or antioxidant.

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

10. Use of the recycled polypropylene composite material according to any one of claims 1 to 8 in the preparation of automobile parts.

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