A fiber-reinforced PCR composite material and its application

Abstract

The present invention discloses a high-performance fiber-reinforced polypropylene (PCR) composite material and an application thereof, belonging to the technical field of recycled plastics. The fiber-reinforced PCR composite material of the present invention comprises the following components, by weight: 50-70 parts of polypropylene, 30-50 parts of recycled polypropylene, 15-30 parts of modified glass fiber, 5-10 parts of a reactive compatibilizer, 0.1-1 part of a beta-nucleating agent, 0.01-0.05 part of a catalyst, and 0.1-2 parts of an antioxidant. The reactive compatibilizer is prepared by copolymerizing a monomer 1 and a monomer 2 to obtain a copolymer, followed by epoxidation modification. The fiber-reinforced PCR composite material provided by the present invention is prepared by adding the modified glass fiber and the reactive compatibilizer to polypropylene and a recycled polypropylene composite material, so that the recycled polypropylene composite material maintains the characteristics of high strength, low VOC, and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of recycled plastics, in particular to a fiber-reinforced PCR composite material and applications thereof. Background Art

[0002] Recycled polypropylene (PP) primarily comes from various PP plastic products used in daily necessities and the dismantling of white appliances. Because the material has been processed and used for extended periods, its mechanical and emission properties are poor. If recycled polypropylene is directly added to a formula for modification, the resulting parts may experience some performance degradation and exhibit an unpleasant odor. If recycled polypropylene is used in automotive interiors, the odor environment inside the vehicle can deteriorate dramatically in hot summer temperatures and in a closed interior, severely impacting the driving experience.

[0003] In the existing technology, the modification and regeneration methods for waste PP generally include physical modification and regeneration such as filling modification, reinforcement modification, toughening modification and blending modification, and chemical modification and regeneration such as cross-linking, grafting and chlorination. Chemical methods are used to modify the recycled plastics, but it is generally necessary to control the proportion of recycled polypropylene within 30%. Once it exceeds 30%, the mechanical properties, thermal properties and odor of the polypropylene composite material will drop significantly, making it no longer meet the use requirements. Summary of the Invention

[0004] In order to overcome the shortcomings of the above-mentioned prior art, the present invention provides a fiber-reinforced PCR composite material and its application. By adding modified glass fiber and reactive compatibilizer to polypropylene and recycled polypropylene composite materials, the recycled polypropylene composite material can still maintain the characteristics of high strength and low VOC.

[0005] The present invention is achieved through the following technical solution: a fiber-reinforced PCR composite material, wherein the raw materials include the following components, by weight: 50-70 parts of polypropylene, 30-50 parts of polypropylene recycled material, 15-30 parts of modified glass fiber, 5-10 parts of reactive compatibilizer, 0.1-1 part of β-nucleating agent, 0.01-0.05 part of catalyst, and 0.1-2 parts of antioxidant, wherein the reactive compatibilizer has the general formula shown in Formula 1:

[0006] Formula 1, where a:b = (1-3): (1:3), and nn is a natural number between 1 and 20.

[0007] Preferably, the reactive compatibilizer is prepared by copolymerizing monomer 1 and monomer 2 to obtain a copolymer and then epoxidizing and modifying the copolymer, wherein the structural formula of monomer 1 is shown in Formula 2, and the structural formula of monomer 2 is shown in Formula 3:

[0008] Formula 2, Formula 3.

[0009] Preferably, the molar ratio of monomer 1 to monomer 2 is (1-3):(1-3), and more preferably, the molar ratio of monomer 1 to monomer 2 is 1:1.

[0010] In a specific embodiment, the modified glass fiber is an aminosilane coupling agent modified glass fiber, and the mass ratio of the aminosilane coupling agent to the glass fiber is (1-5):100.

[0011] In a specific embodiment, the number average molecular weight of the reactive compatibilizer is 3000-6000.

[0012] In a specific embodiment, the preparation method of the monomer 1 is as follows: under nitrogen protection, 7-hydroxycoumarin and 1,2-dibromoethane are dissolved in acetone, potassium carbonate is added, stirred and refluxed at 60-65° C. for 8-12 hours, 5-norbornene-2,3-dicarboximide is added, stirring and reacting is continued for 48-65 hours, filtering, distilling under reduced pressure, and separating by silica gel column chromatography to obtain monomer 1.

[0013] In a specific embodiment, the preparation method of the monomer 2 is as follows: under nitrogen protection, enol and 1,4-bis(bromomethyl)benzene are dissolved in acetone, potassium carbonate is added, stirred at 60-65° C. and refluxed for 8-12 hours, 5-norbornene-2,3-dicarboximide is added, stirring and reacting is continued for 48-65 hours, filtering, distilling under reduced pressure, and separating by silica gel column chromatography to obtain monomer 2.

[0014] Preferably, the enol is selected from one or more of allyl alcohol, 3-butene-1-ol, 3-methyl-2-butene-1-ol, 4-pentene-1-ol, 5-hexene-1-ol, 7-octen-1-ol, 10-undecene-1-ol, 9-decen-1-ol, 18-hydroxyoleyl alcohol, and 19-eicosenol.

[0015] In a specific embodiment, the preparation method of the copolymer is as follows: under a nitrogen atmosphere, monomer 1 and monomer 2 are dissolved in toluene, and the catalyst is dissolved in toluene at the same time, and slowly added dropwise to the monomer solution for ring-opening metathesis polymerization, the reaction temperature is 70~90°C, and after reacting for 2~4h, vinyl ethyl ether is added to quench the reaction, the solvent is evaporated, and the copolymer is obtained by recrystallization.

[0016] Preferably, the catalyst is a Grubbs first generation catalyst, wherein the Grubbs first generation catalyst has high efficiency in catalyzing ring-opening metathesis polymerization, has low vinyl reactivity, has weak metathesis activity on the vinyl group on monomer 2, and can significantly inhibit side reactions.

[0017] In a specific embodiment, the epoxidation modification method is: the copolymer is redissolved in toluene, an antioxidant is added, m-chloroperbenzoic acid is added at 5-15°C, and the reaction is stirred for 4 hours. After the reaction is completed, the polymer is precipitated in methanol and then vacuum-dried to obtain a reactive compatibilizer.

[0018] In a specific embodiment, the polypropylene recycled material includes one or more of polypropylene recycled material for washing machine tubs, polypropylene recycled material for instrument panels, polypropylene recycled material for door interior panels, and polypropylene recycled material for bumpers.

[0019] Preferably, the glass fibers are chopped glass fibers.

[0020] Preferably, the catalyst is an imidazole catalyst or a phosphazene base catalyst, the imidazole catalyst is selected from one or more of 2-methylimidazole, 2-ethyl-4-methylimidazole, and 1-cyanoethyl-2-ethyl-4-methylimidazole, and the phosphazene base catalyst is selected from phosphazene base P4-t-Bu.

[0021] Preferably, the antioxidant is a combination of a phosphite antioxidant and a thioester antioxidant. Preferably, the phosphite antioxidant is one or more of antioxidant 168 or antioxidant 626, and the thioester antioxidant is antioxidant DSTDP.

[0022] Preferably, the polypropylene has a melt flow rate of 25-50 g / (10 min) at 230° C. and 2.16 kg.

[0023] The present invention also provides a method for preparing the fiber-reinforced PCR composite material, comprising the following steps:

[0024] (1) Weighing each raw material and mechanically blending it with a high-speed mixer to obtain a mixed material;

[0025] (2) The mixed material is put into a twin-screw extruder and extruded into granules.

[0026] Another object of the present invention is to protect the application of the fiber-reinforced PCR composite material in automobile interior decoration.

[0027] Beneficial effects

[0028] The present invention provides a fiber-reinforced polypropylene (PCR) composite material. By adding modified glass fiber, a reactive compatibilizer, a β-nucleating agent, and other materials to a polypropylene recycled material, the composite material achieves high strength, high toughness, high temperature resistance, and low odor. The modified glass fiber and the reactive compatibilizer can synergistically enhance the interface. Combined with the β-crystal toughening effect induced by the β-nucleating agent, the PCR composite material can maintain excellent impact resistance and increase the heat deformation temperature. The reactive compatibilizer uses a copolymerized norbornene modified with coumarin and epoxy groups. The active epoxy groups react with polar impurities (amine, carbonyl, and hydroxyl groups) in the recycled polypropylene, eliminating the source of odor in the recycled polypropylene material and reducing the VOC emission of the polypropylene through chemical reactions. Furthermore, the multiple reactive sites can react with the recycled polypropylene chain segments to form a cross-linked network, thereby extending the molecular weight of the recycled polypropylene and improving its mechanical properties. Furthermore, the epoxy active groups on the reactive compatibilizer can bond with the silanol groups on the glass fiber surface or the amino groups on the aminosilane coupling agent to form a PP-compatibilizer-glass fiber covalent network, enhancing interfacial compatibility. Furthermore, the coumarin aromatic groups in the reactive compatibilizer neutralize odors, effectively masking the odor of recycled materials and emitting a refreshing hay aroma, effectively covering the odor of recycled polypropylene. The rigid polynorbornene rings in the reactive compatibilizer's backbone effectively enhance the thermal stability of PCR composites and raise their heat deformation temperature. Research has shown that the modified recycled polypropylene composites fully meet the requirements for automotive interior applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the synthetic route of monomer 1;

[0030] Figure 2 is the H NMR spectrum of monomer 1;

[0031] Figure 3 This is the synthetic route of monomer 2;

[0032] Figure 4 is the H NMR spectrum of monomer 2;

[0033] Figure 5 This is the synthetic route of reactive compatibilizer 1;

[0034] Figure 6 This is the infrared spectrum of reactive compatibilizer 1. DETAILED DESCRIPTION

[0035] 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 embodiments described 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 making any creative efforts shall fall within the scope of protection of the present invention.

[0036] In the examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0037] The raw materials used in the embodiments and comparative examples are now described as follows:

[0038] Polypropylene recycled material: The recycling source is the inner drum of a pulsator washing machine, Green Recycling Co., Ltd.

[0039] Polypropylene: EP548R, 230°C, melt flow rate of 28 g / 10 min at 2.16 kg, CNOOC Shell;

[0040] Modified glass fiber: 508A, alkali-free glass fiber chopped strands, impregnated with 1wt% aminosilane coupling agent, manufactured by Jushi, China;

[0041] Glass fiber, 508A, E-glass fiber chopped strand, China Jushi;

[0042] β-nucleating agent: TMB-5, Shanxi Chemical Research Institute;

[0043] Catalyst: phosphazene base P4-t-Bu, Guangdong Wengjiang Chemical Reagent Co., Ltd.;

[0044] Antioxidant: a commercially available mixture of antioxidant 168 and antioxidant DSTDP in a mass ratio of 1:1;

[0045] Monomer 1: Homemade, prepared as follows: 0.11 mol 7-hydroxycoumarin and 0.1 mol 1,2-dibromoethane were placed in a 250 mL three-necked flask, 20 mL acetone and 0.25 mol potassium carbonate were added, the system temperature was controlled at 60°C, and the reaction was stirred under nitrogen for 12 hours. 0.1 mol 5-norbornene-2,3-dicarboximide was added, and the stirring reaction was continued for 65 hours. The reaction solution was filtered and distilled under reduced pressure. The reaction solution was separated by silica gel column chromatography (the eluent was a 1:1 ratio of petroleum ether and dichloromethane) to obtain monomer 1 with a yield of 60.6%. The reaction formula is as follows: Figure 1 As shown, the H NMR spectrum is Figure 2 As shown; from the chemical shift and integration on the H NMR spectrum (400 MHz, CDCl3), it can be seen that norbornene-grafted coumarin was successfully synthesized.

[0046] Monomer 2: Homemade, prepared as follows: 0.11 mol of undecenol and 0.1 mol of 1,4-bis(bromomethyl)benzene were placed in a 250 mL three-necked flask, 20 mL of acetone and 0.25 mol of potassium carbonate were added, the system temperature was controlled at 60°C, and the reaction was stirred under nitrogen for 12 hours. 0.1 mol of 5-norbornene-2,3-dicarboximide was added and the reaction was continued with stirring for 65 hours. The reaction solution was extracted alternately with acetone and distilled water until neutral, the organic phase was separated, and crystals were precipitated after cooling to obtain norbornene-grafted undecene with a yield of 74.5%. The reaction formula is as follows: Figure 3 As shown, the H NMR spectrum (400 MHz, CDCl3) Figure 4 As shown; from the chemical shift and integration of the H NMR spectrum, it can be seen that norbornene-grafted undecene was successfully synthesized.

[0047] Monomer 2-B: Homemade. The preparation method is similar to Monomer 2, except that undecenyl alcohol is replaced by 3-buten-1-ol. The yield is 75.3%.

[0048] Reactive compatibilizer 1: Homemade, the preparation method is as follows: Under a nitrogen atmosphere, add 0.2 mol of monomer 1, 0.2 mol of monomer 2, and 200 ml of toluene to a reactor, add 0.1 mol of Grubbs first-generation catalyst and dissolve it in toluene, slowly add it dropwise to the reactor, and carry out ring-opening metathesis polymerization. The reaction temperature is 80°C. After reacting for 2 hours, vinyl ethyl ether is added to quench the reaction, the solvent is evaporated, and a copolymer is obtained by recrystallization. The copolymer is redissolved in toluene, antioxidant 2246 is added, and m-chloroperbenzoic acid is added at 15°C. The reaction is stirred for 4 hours. After the reaction is completed, the polymer is precipitated in methanol and then vacuum dried to obtain reactive compatibilizer 1. The reaction formula is as follows: Figure 5 As shown, the infrared spectrum of the reactive compatibilizer is as follows Figure 6 The infrared spectrometer is ThermoNicolet is20, the form is powder, the ATR mode is selected at room temperature, and the scanning range is 3800cm -1 ~500cm -1 , the number of scans is 32 times, the resolution is 4cm -1 , automatically deducting the atmospheric background. -1 and 2867cm -1 The absorption peak of methylene was detected at 1704 cm -1 The C=O absorption peak was detected at 1250 cm -1 The absorption peak of COC was detected at 901 cm -1 and 718cm -1 The absorption peak of epoxy group was detected at 1400 nm. The number average molecular weight was 4260 as determined by GPC.

[0049] Reactive compatibilizer 2: Compared with reactive compatibilizer 1, the difference is that the addition amount of monomer 1 is 0.3 mol, and the addition amount of monomer 2 is 0.1 mol. The number average molecular weight determined by GPC is 3420.

[0050] Reactive compatibilizer 3: Compared with reactive compatibilizer 1, the difference is that the addition amount of monomer 1 is 0.1 mol, and the addition amount of monomer 2 is 0.3 mol. The number average molecular weight determined by GPC is 4890.

[0051] Reactive compatibilizer 4: Compared with reactive compatibilizer 1, the difference is that monomer 2 is replaced by monomer 2-B;

[0052] Comparative compatibilizer 5: Compared with compatibilizer 1, the difference is that no epoxidation modification is performed;

[0053] Comparative compatibilizer 6: Compared with compatibilizer 1, the difference is that monomer 1 is not added;

[0054] Comparative compatibilizer 7: Compared with compatibilizer 1, the difference is that monomer 2 is not added;

[0055] Comparative compatibilizer 8: commercially available compatibilizer, glycidyl methacrylate grafted, specifically POE-g-GMA, SOG-03, Jiayirong;

[0056] Unless otherwise specified, the components and raw materials used in the examples and comparative examples of the present invention are all commercially available raw materials, and the components and raw materials used in each parallel experiment are all of the same kind.

[0057] Examples and Comparative Examples

[0058] A fiber-reinforced PCR composite material and a preparation method thereof, the weight formula of which is shown in Table 1, and the preparation method is as follows:

[0059] (1) Weighing each raw material and mechanically blending it with a high-speed mixer to obtain a mixed material;

[0060] The mixed material is put into a twin-screw extruder and extruded into granules. The temperatures of each section of the twin-screw extruder are 40, 80, 210, 210, 210, 210, 210, 210, 205, and 205°C (die head), and the screw speed is 450r / min.

[0061] Table 1 Composition and proportion of fiber-reinforced PCR composite materials (parts by weight)

[0062]

[0063] The fiber-reinforced PCR composite materials prepared in the examples and comparative examples were subjected to the following performance tests, and the results are shown in Table 2.

[0064] 1. Tensile strength: Tested in accordance with ISO 527-2—2012 “Plastics — Determination of tensile properties” at a speed of 50 mm / min;

[0065] 2.23°C notched impact strength: tested in accordance with ISO 179-1 / 1eA-2010 “Determination of pendulum impact properties”;

[0066] 3. Odor Evaluation: Material odor was evaluated according to the Volkswagen standard PV3900-2000, "Odor Test for Automotive Interior Components." A 50g sample was placed in a 1L odor bottle, heated in an 80°C oven for 2 hours, removed, and cooled to (65±5)°C before evaluation. The odor rating was as follows: 1 - no odor, 2 - slight odor, 3 - noticeable odor but not objectionable, 4 - objectionable, 5 - very objectionable, and 6 - unbearable.

[0067] 4. VOC content determination: The VOC of the sample was determined according to the SMTC 5400018 VOC sampling and testing method for automotive parts using a 100L bag and a 500cm 2 model.

[0068] 5. Deflection Temperature under Load: Determine the deflection temperature under load according to the method of GB / T 1634.2-2019 "Plastics — Determination of Deflection Temperature under Load — Part 2: Plastics and Ebonite" with a load of 0.45 MPa and a heating rate of 120°C.

[0069] Table 2 Performance test results of fiber-reinforced PCR composites

[0070]

[0071] It can be seen from Example 1 and Comparative Example 6 that the addition of the reactive compatibilizer not only enables the recycled polypropylene material with 50% recycled polypropylene to obtain performance close to that of new polypropylene, but also effectively improves the odor level of the recycled polypropylene, making it meet the requirements for use in automotive interior materials.

[0072] The performance of the PCR composite materials obtained using commercially available compatibilizers in Example 1 and Comparative Example 4 was compared. The rigid polynorbornene main chain of the reactive compatibilizer improved the heat resistance of the PCR composite material, the coumarin group improved the odor performance of the PCR composite material, and the epoxy group reacted with the amino group, hydroxyl group, etc. generated by the degradation of recycled polypropylene to effectively extend the polypropylene chain segment, and eliminated the odorous groups generated by the amino group and the like through chemical reactions, thereby reducing the VOC of the PCR composite material and improving the emission performance of the PCR composite material.

[0073] It can be seen from Examples 1, 3, 4 and Comparative Examples 2 and 3 that when the molar ratio of comonomer 1 to monomer 2 of the reactive compatibilizer is within a certain range, the comprehensive performance of the obtained PCR composite material is better.

[0074] It can be seen from Example 1 and Comparative Example 5 that the glass fiber surface-modified with the aminosilane coupling agent has better compatibility with the PCR composite material and better interfacial bonding strength, thereby improving the mechanical properties.

[0075] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A fiber-reinforced PCR composite material, characterized in that: The composition comprises the following components by weight: 50-70 parts of polypropylene, 30-50 parts of recycled polypropylene, 15-30 parts of modified glass fiber, 5-10 parts of reactive compatibilizer, 0.1-1 parts of β-nucleating agent, 0.01-0.05 parts of catalyst, and 0.1-2 parts of antioxidant. The reactive compatibilizer has the general formula shown in Formula 1: Formula 1, where a:b = (1~3): (1:3), and n is a natural number between 1 and 20.

2. The fiber-reinforced PCR composite material according to claim 1, wherein: The reactive compatibilizer is prepared by copolymerizing monomer 1 and monomer 2 to obtain a copolymer and then epoxidizing and modifying it. The structural formula of monomer 1 is shown in Formula 2, and the structural formula of monomer 2 is shown in Formula 3: Formula 2, Formula 3.

3. The fiber-reinforced PCR composite material according to claim 1, wherein: The modified glass fiber is an aminosilane coupling agent modified glass fiber, and the mass ratio of the aminosilane coupling agent to the glass fiber is (1-5):

100.

4. The fiber-reinforced PCR composite material according to claim 1, wherein: The number average molecular weight of the reactive compatibilizer is 3000-6000.

5. The fiber-reinforced PCR composite material according to claim 2, wherein: The preparation method of monomer 1 is as follows: under nitrogen protection, 7-hydroxycoumarin and 1,2-dibromoethane are dissolved in acetone, potassium carbonate is added, stirring and reflux reaction are carried out at 60-65° C. for 8-12 hours, 5-norbornene-2,3-dicarboximide is added, stirring and reaction are continued for 48-65 hours, filtering, distilling under reduced pressure, and separating by silica gel column chromatography to obtain monomer 1; the preparation method of monomer 2 is as follows: under nitrogen protection, enol and 1,4-bis(bromomethyl)benzene are dissolved in acetone, potassium carbonate is added, stirring and reflux reaction are carried out at 60-65° C. for 8-12 hours, 5-norbornene-2,3-dicarboximide is added, stirring and reaction are continued for 48-65 hours, filtering, distilling under reduced pressure, and separating by silica gel column chromatography to obtain monomer 2.

6. The fiber-reinforced PCR composite material according to claim 2, wherein: The preparation method of the copolymer is as follows: under a nitrogen atmosphere, monomer 1 and monomer 2 are dissolved in toluene, and a catalyst is dissolved in toluene at the same time, and the mixture is slowly added dropwise to the monomer solution to carry out ring-opening metathesis polymerization. The reaction temperature is 70-90° C., and after reacting for 2-4 hours, vinyl ethyl ether is added to quench the reaction, the solvent is evaporated, and the copolymer is obtained by recrystallization.

7. The fiber-reinforced PCR composite material according to claim 2, wherein: The epoxidation modification method comprises: redissolving the copolymer in toluene, adding an antioxidant, adding m-chloroperbenzoic acid at 5-15° C., stirring and reacting for 4 hours, and after the reaction, precipitating the polymer in methanol and then vacuum drying to obtain a reactive compatibilizer.

8. The fiber-reinforced PCR composite material according to claim 1, wherein: The polypropylene recycled material includes one or more of polypropylene recycled material for washing machine tubs, polypropylene recycled material for instrument panels, polypropylene recycled material for door interior panels, and polypropylene recycled material for bumpers; the glass fiber is chopped glass fiber; the catalyst is an imidazole catalyst or a phosphazene base catalyst; the antioxidant is a compound of a phosphite antioxidant and a thioester antioxidant; and the melt flow rate of the polypropylene at 230° C. and 2.16 kg is 25-50 g / (10 min).

9. The method for preparing a fiber-reinforced PCR composite material according to any one of claims 1 to 8, wherein: The following steps are involved: (1) Weighing each raw material and mechanically blending it with a high-speed mixer to obtain a mixed material; (2) The mixed material is put into a twin-screw extruder and extruded into granules.

10. Use of the fiber-reinforced PCR composite material according to any one of claims 1 to 8 in automobile interior decoration.

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