PCR (Polymerase Chain Reaction) polypropylene modified composite material and preparation method thereof
By adding highly crystalline copolymer polypropylene and high-mesh talc to PCR polypropylene, along with toughening agents and compatibilizers, a modified composite material with balanced mechanical properties was prepared. This solved the performance loss problem caused by the secondary recycling of PCR polypropylene and achieved environmentally friendly material preparation.
Patent Information
- Application Number
- CN202511495675.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-20
- Publication Date
- 2025-12-19
AI Technical Summary
The secondary recycling of PCR polypropylene results in severe loss of mechanical properties, and the use of plasticizers may lead to excessive phthalate levels, which violates environmental protection requirements.
A PCR-modified polypropylene composite material was prepared by using highly crystalline copolymer polypropylene and high-mesh talc powder, combined with toughening agents and compatibilizers, avoiding the use of plasticizers and improving mechanical properties through multi-component formulation.
It achieves a balanced improvement in mechanical properties, meets environmental protection requirements, avoids the generation of phthalates, and satisfies environmental standards.
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of modified polymer materials, and particularly relates to a PCR polypropylene modified composite material and a preparation method thereof. BACKGROUND
[0002] Plastics are widely used in life, and their shadows can be seen everywhere in automobiles and household appliances. However, with the increasing use of plastics and their difficulty in degradation, global environmental pollution is exacerbated. In order to protect the environment, reduce carbon emissions, and actively respond to the "double carbon strategy target" of China, post-consumer recycled (PCR) plastics have become the focus of attention. In addition to the government advocating the use of PCR plastics by society, some countries have laws and regulations that require the use of PCR plastics to meet environmental protection requirements.
[0003] Polypropylene is a common thermoplastic plastic, and is often used for lightweight and cost reduction design of automobiles and household appliances due to its low density and low price. At present, some polypropylene materials gradually replace engineering plastics such as nylon and ABS, so post-consumer recycled polypropylene (PCR-PP) has great application prospects. However, due to the secondary recycling of PCR-PP, the mechanical properties are seriously lost. In order to improve the performance, some enterprises mix plasticizers with enhancing function into PCR-PP, melt extrude and granulate. However, such plasticizers can cause phthalate esters (PAEs) to exceed the standard, which does not meet the environmental protection requirements. Therefore, it is necessary to design a post-consumer recycled polypropylene composite material that takes into account the mechanical properties and environmental protection. SUMMARY
[0004] The application provides a PCR polypropylene modified composite material and a preparation method thereof, so as to solve the technical problem that the secondary recycling of PCR polypropylene can cause serious loss of mechanical properties.
[0005] To solve the above technical problems, the PCR polypropylene modified composite material provided by the application comprises PCR-PP (post-consumer recycled polypropylene resin), PP, a toughening agent, a compatibilizer, talcum powder and an antioxidant. The talcum powder is at least partially talcum powder with a mesh size of 2500 or more, and the PP is a copolymerized polypropylene resin with a crystallinity of 35-55%.
[0006] The application simulates the comprehensive mechanical properties of ordinary polypropylene resin by adding high-crystallinity copolymerized polypropylene and superfine talcum powder with a high mesh size, and adding a certain amount of a toughening agent, and specifically relates to tensile strength, bending modulus and impact strength, rather than adding a single component to increase a certain aspect of performance, but sacrificing another aspect of mechanical properties.
[0007] Alternatively, the talcum powder is composed of talcum powder A with a mesh size of 1000 and talcum powder B with a mesh size of 3000.
[0008] Optionally, the talc A and talc B are in a ratio of 1: (0.5-1.5) by weight, preferably 1:1.
[0009] Optionally, the toughening agent is polyolefin elastomer (POE).
[0010] POE is a thermoplastic elastomer that is polymerized in situ by using metallocene catalysts for ethylene and α-olefins, in which the polyethylene chain crystalline region (resin phase) acts as a physical crosslinking point, has typical plastic properties, and after adding a certain amount of α-olefin, the crystalline region of the polyethylene chain is weakened, forming an amorphous region (rubber phase) that exhibits rubber elasticity, so that the product also has the properties of an elastomer.
[0011] Optionally, the toughening agent is ethylene and α-octene copolymer, ethylene and α-hexene copolymer, or ethylene and α-butene copolymer.
[0012] Optionally, the compatibilizer is polypropylene grafted maleic anhydride.
[0013] Optionally, the antioxidant is composed of antioxidant 1010 and antioxidant 168.
[0014] Optionally, the antioxidant 1010 and antioxidant 168 are in a ratio of 1: (0.5-2) by weight, preferably 1:1.
[0015] Optionally, the raw materials are as follows by weight:
[0016] PCR-PP 25-75 parts
[0017] PP 10-50 parts
[0018] Toughening agent 3-4 parts
[0019] Compatibilizer 2-4 parts
[0020] Talc 20-25 parts
[0021] Antioxidant 0.2-0.4 parts.
[0022] Optionally, the raw materials are as follows by weight:
[0023] PCR-PP 50 parts
[0024] PP 20-25 parts
[0025] Toughening agent 3 parts
[0026] Compatibilizer 2-4 parts
[0027] Talc 20 parts
[0028] Antioxidant 0.2 parts.
[0029] Optionally, the PCR-PP has a melt flow rate of 9-15 g / 10 min under the test conditions of 230℃ and 2.16 kg.
[0030] The application also provides a preparation method of the PCR polypropylene modified composite material, which comprises the following steps: uniformly mixing PCR-PP, PP, a toughening agent, a compatilizer, talcum powder and an antioxidant in a stirrer, then adding the stirrer into a twin-screw extruder, and granulating after melt extrusion, so that the PCR polypropylene modified composite material is obtained.
[0031] Optionally, the stirring speed of the stirrer is 50 r / min, and the rotating speed of the twin-screw extruder is 300-500 r / min.
[0032] Optionally, the melt temperature of the twin-screw extruder is set to 220℃.
[0033] Optionally, the die temperature of the twin-screw extruder is set to 220℃, and the temperature of the 1-10 zones is set to 180, 200, 210, 220, 220, 220, 220, 220, 220, 220℃, respectively.
[0034] Compared with the prior art, the technical scheme provided by the application simulates a post-consumer recycled polypropylene modified composite material with mechanical properties equivalent to those of ordinary copolymerized polypropylene by using multiple components, and avoids the addition of rigid plasticizers and the generation of benzene-containing substances, thereby meeting environmental protection requirements. DETAILED DESCRIPTION
[0035] In order to facilitate understanding, the PCR polypropylene modified composite material and the preparation method thereof will be described below in combination with examples, and it should be understood that these examples are only used to illustrate the application and are not used to limit the scope of the application.
[0036] Examples 1-6
[0037] The components of the raw materials are weighed according to the formula, uniformly mixed in a stirrer at a stirring speed of 50 r / min, and then added into a twin-screw extruder, wherein the temperature of the 1-10 zones of the twin-screw extruder is set to 180, 200, 210, 220, 220, 220, 220, 220, 220, 220℃, respectively, the die temperature is set to 220℃, the melt temperature is set to 220℃, the rotating speed of the twin-screw extruder is 300-500 r / min, and after melt extrusion, granulation is performed, so that the PCR polypropylene modified composite material is obtained.
[0038] The raw materials include PRR-PP, PP, toughening agent, compatibilizer, talc and antioxidant. The melt flow rate of the PRR-PP is 28.0 g / 10 min under the test condition of 230℃ and 2.16 kg, the PP is high crystallinity copolymer polypropylene resin, the melt flow rate of which is 9.2 g / 10 min under the test condition of 230℃ and 2.16 kg. The toughening agent of Example 3 is ethylene and α-butene copolymer, and the toughening agent of other examples is ethylene and α-octene copolymer. The compatibilizer is polypropylene grafted maleic anhydride. The talc is composed of 1000 mesh talc A and 3000 mesh talc B. The antioxidant is composed of antioxidant 1010 and antioxidant 168.
[0039] The components of Examples 1-6 are shown in Table 1 by weight parts.
[0040] Table 1
[0041]
[0042] Comparative Example 1
[0043] The difference from Example 2 is that the polypropylenes are all common copolymer polypropylenes with a crystallinity of 33.9%, no PCR-PP is added, the particle size of talc is all 1000 mesh, and no additional toughening agent is added. This comparative example is a benchmark sample of the present scheme.
[0044] Comparative Example 2
[0045] The difference from Example 2 is that 20 parts of talc are all talc A, that is, no high mesh talc B is added.
[0046] Comparative Example 3
[0047] The difference from Example 2 is that the polypropylene is replaced by PCR-PP, that is, no high crystallinity PP is added.
[0048] Comparative Example 4
[0049] The difference from Example 2 is that the polypropylene is a common copolymer polypropylene with a crystallinity of 33.9%.
[0050] Comparative Example 5
[0051] The difference from Example 2 is that no toughening agent is added.
[0052] Comparative Example 6
[0053] The difference from Example 2 is that the amount of talc added is 30 parts, and talc A and talc B are each 15 parts.
[0054] The products prepared in Examples 1-6 and Comparative Examples 1-6 were subjected to performance tests, and the test items, test conditions and test standards are shown in Table 2.
[0055] Table 2
[0056] Test item Test standard Test condition Crystallinity of PP ISO 11357 30°C / min, N 2： 50 ml / min Tensile strength ISO 527 23℃, 50 mm / min Flexural strength ISO 178 23℃, 2 mm / min Flexural modulus ISO 178 23℃, 2 mm / min Izod notched impact strength ISO 180 23℃，5.95J
[0057] The test results are shown in Table 3.
[0058] Table 3
[0059] Test item Crystallinity of raw material PP Crystallinity after modification and compounding Tensile strength Flexural strength Flexural modulus Izod notched impact strength Unit % % MPa MPa MPa [kJ / m 2 ]]> Example 1 40.7 30.5 30 47 2415 7.1 Example 2 40.7 28.1 28 44 2209 6.8 Example 3 40.7 27.9 29 45 2315 6.6 Example 4 40.7 25.9 28 43 2185 6.9 Example 5 40.7 28.0 29 45 2333 6.7 Example 6 40.7 28.3 29 46 2408 6.9 Comparative Example 1 33.9 26.8 28 43 2229 6.6 Comparative Example 2 40.7 25.5 28 41 2071 6.9 Comparative Example 3 31.7 22.7 27 41 2095 5.9 Comparative Example 4 33.9 24.3 27 42 2133 6.1 Comparative Example 5 40.7 29.6 34 53 2747 5.1 Comparative Example 6 40.7 21.3 30 46 2705 5.3
[0060] From the performance test data above, it can be found that, by increasing the proportion of PP, the tensile strength, bending strength, bending modulus and impact strength of the composite material are significantly improved in Example 1 compared with Example 2, but this is contrary to the original intention of using more PCR-PP.
[0061] In summary, the performance of the formulation of Example 2 is consistent with that of the sample of Comparative Example 1, and it can completely replace ordinary copolymerized polypropylene.
[0062] It can be found that polyolefin elastomer (POE) as a toughening agent has a similar effect compared with Example 2.
[0063] In Example 4, the proportion of 3000 mesh talc B is slightly less than that in Example 2, the bending strength and bending modulus decrease, i.e. the rigidity slightly decreases; the cantilever beam notched impact strength increases, i.e. the toughness slightly improves.
[0064] In Example 5, the amount of the added compatibilizer is increased, and the performance is basically unchanged.
[0065] In Example 6, the amount of the added antioxidant is increased, and the performance is slightly improved, but the cost is increased.
[0066] In Comparative Example 2, compared with Example 2, no 3000 mesh talc B is added, the bending strength and bending modulus decrease, i.e. the rigidity slightly decreases; the cantilever beam notched impact strength increases, i.e. the toughness slightly improves.
[0067] In Comparative Example 3, compared with Example 2, since no high crystallinity PP is added, the comprehensive performance of the composite material is low, and in particular, the impact strength is lower than 6 kJ / m 2 .
[0068] In Comparative Example 4, compared with Example 2, the added PP has a lower crystallinity, and the overall mechanical performance decreases, which reflects the necessity of high crystallinity copolymerized polypropylene.
[0069] In Comparative Example 5, compared with Example 2, no toughening agent is added, the rigidity is improved, and the toughness is greatly reduced.
[0070] Comparative Example 6 increases the amount of talcum powder added, the tensile strength, bending strength and bending modulus of the composite material are improved, but the impact strength is significantly decreased. Mineral powder filling provides rigidity as a skeleton, the more filling, the better the rigidity, but when the proportion is too high, the proportion of polypropylene decreases, and the crystallization area decreases, which can be found from the product crystallinity, in addition, excessive mineral powder will hinder the crystallization of polypropylene, thus reducing the rigidity and toughness of the product. The experimental results of Comparative Example 6 are the result of the interaction of the two.
[0071] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it. Although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.
Claims
1. A PCR-modified polypropylene composite material, characterized in that, The raw materials include PCR-PP, PP, toughening agent, compatibilizer, talc and antioxidant, wherein the talc is at least partially 2500 mesh or higher, and the PP is a copolymer polypropylene resin with a crystallinity of 35-55%.
2. The PCR-modified polypropylene composite material according to claim 1, characterized in that, The talc powder is composed of 1000-mesh talc powder A and 3000-mesh talc powder B.
3. The PCR-modified polypropylene composite material according to claim 2, characterized in that, The talc powder A and talc powder B are mixed in a weight ratio of 1:(0.5-1.5), preferably 1:
1.
4. The PCR-modified polypropylene composite material according to claim 1, characterized in that, The toughening agent is a polyolefin elastomer.
5. The PCR-modified polypropylene composite material according to claim 4, characterized in that, The toughening agent is an ethylene-α-octene copolymer, an ethylene-α-hexene copolymer, or an ethylene-α-butene copolymer.
6. The PCR-modified polypropylene composite material according to claim 1, characterized in that, The compatibilizer is polypropylene grafted with maleic anhydride.
7. The PCR-modified polypropylene composite material according to claim 1, characterized in that, The antioxidant is composed of antioxidant 1010 and antioxidant 168.
8. The PCR-modified polypropylene composite material according to claim 1, characterized in that, The components of the raw material are as follows by weight: PRR-PP 25-75 parts PP 10-50 portions 3-4 parts toughening agent 2-4 parts compatibilizer 20-25 parts talcum powder Antioxidant 0.2 to 0.4 parts.
9. The PCR-modified polypropylene composite material according to claim 1, characterized in that, The components of the raw material are as follows by weight: 50 PCR-PP samples PP 20-25 parts 3 parts toughening agent 2-4 parts compatibilizer 20 parts talcum powder Antioxidant 0.2 parts.
10. A method for preparing the PCR-modified polypropylene composite material according to any one of claims 1-9, characterized in that, PCR-PP, PP, toughening agent, compatibilizer, talc and antioxidant are mixed in a mixer, then fed into a twin-screw extruder, and granulated after melt extrusion to obtain PCR polypropylene modified composite material.