Polypropylene composite, method for producing same, and automobile parts manufactured by using same

Abstract

The present invention relates to a polypropylene composite and a method for producing same. The polypropylene composite according to the present invention can be used as a material for producing automobile parts such as an electric vehicle motor room cover. Environmental-friendliness is achieved by recycling a waste phenolic resin. A method for producing a polypropylene composite according to an embodiment of the present invention comprises: a step for preparing a waste phenolic resin; and a step for producing a mixture by mixing polypropylene (PP), a compatibilizer, and the waste phenolic resin.

Description

Polypropylene composite, method of manufacturing the same, and automotive part manufactured using the same

[0001] The present invention relates to a polypropylene composite and a method for manufacturing the same. The polypropylene composite of the present invention can be used as a material for manufacturing automotive parts, such as electric vehicle motor room covers. It is environmentally friendly by recycling waste phenolic resin.

[0002] The present invention is the result of the local government-university cooperation-based regional innovation project conducted in 2024 with funding from the Ministry of Education and support from the National Research Foundation of Korea (2021RIS-004).

[0003] Phenolic resin is a thermosetting resin widely used in various fields, such as electronic components, the electrical industry, and automotive parts, due to its excellent heat resistance and mechanical strength. However, because phenolic resin does not melt again once it is cured due to its thermosetting properties, it is difficult to recycle the waste resin. Due to these characteristics, the reuse of phenolic resin has been limited, and it is mainly disposed of as waste, causing environmental problems.

[0004] In particular, waste such as sprues and runners generated during the manufacturing process of phenolic resins amounts to about 15–20% of the total production volume, and this accumulates as a significant amount of waste. Sprues and runners are used as pathways for plastic materials to move within the mold, and as unnecessary parts remaining after the product is molded, they are ultimately discarded.

[0005] In the past, various physical and chemical methods have been studied to recycle discarded phenolic resins, but the difficulty of recycling remains a major problem. Phenolic resins generate by-products during thermal decomposition, and it is difficult to recover them as pure chemical raw materials. As a result, chemical recycling faces technical limitations and is not effective from an economic perspective.

[0006] Related prior art is Korean Published Patent Application No. 10-2024-0135380.

[0007] The present invention aims to provide a polypropylene composite and a method for manufacturing the same, which enables the recycling of waste phenolic resin, thereby reducing resource waste and preventing environmental pollution.

[0008] In addition, the present invention has excellent heat resistance and mechanical properties.

[0009] In addition, the present invention can be applied to high-performance parts requiring durability, such as automotive parts.

[0010] A method for manufacturing a polypropylene composite according to an embodiment of the present invention comprises the steps of preparing waste phenol resin and mixing polypropylene (PP), a compatibilizer, and waste phenol resin to prepare a mixture.

[0011] The step of preparing the waste phenol resin above may be to prepare the waste phenol resin by crushing the phenol resin and sieving it through a sieve of 160 to 180 mesh.

[0012] Based on the above polypropylene, it may contain 8 to 12 phr of the above compatibilizer and 25 to 35 phr of the above waste phenol resin.

[0013]

[0014] A polypropylene composite according to an embodiment of the present invention comprises polypropylene (PP), a compatibilizer, and waste phenol resin, and can be manufactured by the method described above.

[0015] Based on the above polypropylene, it may contain 8 to 12 phr of the above compatibilizer and 25 to 35 phr of the above waste phenol resin.

[0016]

[0017] An automotive part according to an embodiment of the present invention comprises a polymer matrix and a polypropylene composite dispersed and disposed in said polymer matrix. The polypropylene composite is as described above.

[0018] The polypropylene composite and the method for manufacturing the same according to the embodiments of the present invention enable the recycling of waste phenolic resin, thereby reducing resource waste and preventing environmental pollution.

[0019] In addition, the present invention has excellent heat resistance and mechanical properties.

[0020] In addition, the present invention can be applied to high-performance parts requiring durability, such as automotive parts.

[0021] FIG. 1 is a flowchart of a method for manufacturing a polypropylene composite according to an embodiment of the present invention.

[0022] Figure 2 shows the FTIR analysis results of Examples 1 to 3, Comparative Examples 1 to 3, and Polypropylene (PP).

[0023] Figure 3 shows the tensile strength measurement results of Examples 1 to 3, Comparative Examples 1 to 3, and Polypropylene.

[0024] Figure 4 shows the measurement results of the flexural modulus of Polypropylene in Examples 1 to 3 and Comparative Examples 1 to 3.

[0025] Figure 5 shows the tensile strength measurement results of Examples 3 to 5, Comparative Example 3, and Polypropylene.

[0026] Figure 6 shows the results of measuring the flexural modulus of Examples 3 to 5 and Comparative Example 3, and Polypropylene.

[0027] Figure 7 shows the results of measuring the elongation of Polypropylene in Examples 3 to 5 and Comparative Example 3.

[0028] Figure 8 shows the impact strength measurement results of Examples 3 to 5, Comparative Example 3, and Polypropylene.

[0029] Hereinafter, preferred embodiments of the present invention are described as follows with reference to the attached drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. Furthermore, embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

[0030]

[0031] A polypropylene composite according to an embodiment of the present invention comprises polypropylene (PP), a compatibilizer, and waste phenol resin. Based on the polypropylene, the composite may comprise 8 to 12 phr of the compatibilizer and 25 to 35 phr of the waste phenol resin.

[0032] A method for manufacturing a polypropylene composite according to an embodiment of the present invention comprises the steps of preparing waste phenol resin and mixing polypropylene (PP), a compatibilizer, and waste phenol resin to prepare a mixture. One embodiment may further include the step of processing the mixture into the form of pellets or powder after the step of preparing the mixture.

[0033]

[0034] The waste phenol resin prepared in the step of preparing the waste phenol resin above is phenol resin collected for recycling and may be phenol resin by-products such as discarded sprues and runners. Phenolic resin is basically a polymer resin formed through a condensation reaction between phenol and formaldehyde. The chemical formulas of phenol and formaldehyde, which are the constituent units of phenol resin, are as follows.

[0035] Phenol: C6H5OH

[0036] Formaldehyde: CH2O

[0037] The basic structure formed by the condensation reaction of the above phenol and formaldehyde is a phenol unit connected to each other by a methylene bridge (-CH2-). The repeating unit of the phenol resin is −C6H4−CH2−C6H4−.

[0038] The aforementioned waste phenol resin has the characteristic of maintaining a hard solid state after hardening at high temperatures during the manufacturing process, and due to its thermosetting properties, it is difficult to reprocess or recycle once hardened.

[0039] In the present invention, recycling efficiency can be increased by crushing waste phenol resin to an appropriate size. In one embodiment, the waste phenol resin may be sieved through a sieve of 160 to 180 mesh after crushing. If the particle size of the waste phenol resin is too large, there is a problem in that dispersibility is reduced, interfacial adhesion is weakened, and the surface quality of the composite deteriorates. Conversely, if the particle size is too large, clumping occurs, making dispersion difficult and filling into the polymer matrix difficult, and flow characteristics are reduced, resulting in poor processability.

[0040]

[0041] The step of preparing the above mixture involves mixing polypropylene (PP), a compatibilizer, and waste phenol resin using a stirrer or mixer.

[0042]

[0043] The above-mentioned waste phenolic resin acts as a filler and functions to improve the mechanical and thermal properties of the polypropylene composite. The above-mentioned waste phenolic resin is the one previously described.

[0044] Waste phenolic resin possesses excellent mechanical properties, improving the tensile strength and flexural modulus of composites. Furthermore, as a thermosetting resin, waste phenolic resin exhibits superior heat resistance, enabling composite materials to maintain stable properties even in high-temperature environments. These characteristics play a crucial role, particularly in applications such as electric motor covers. Additionally, waste phenolic resin contributes to weight reduction while serving as a filler. Composites combined with polypropylene can maintain strong mechanical performance while remaining lightweight, making them suitable for products requiring lightweighting, such as automotive and electronic components.

[0045] In this step, the waste phenol resin may be included in an amount of 25 to 35 phr based on the polypropylene. If the content of the waste phenol resin is low, it does not sufficiently function as a filler, so properties such as heat resistance or flexural modulus are not properly exhibited. Conversely, if the content is high, the phenol resin is excessively distributed within the composite, resulting in non-uniform mechanical properties and poor adhesion at the interface. Consequently, tensile strength, elongation, impact strength, etc., decrease.

[0046]

[0047] The aforementioned polypropylene (PP) serves as the base material. This polypropylene is used as the primary material to maintain the physical and mechanical properties of the composite. As a plastic with excellent mechanical properties, polypropylene forms the basic structure of the composite containing waste phenol resin and a compatibilizer (MA-g-PP). Furthermore, polypropylene imparts flexibility and impact resistance to the composite, and its low specific gravity enables the lightweighting of the composite material. Polypropylene possesses characteristics that facilitate molding and processing, thereby facilitating the easy processing of the composite material containing waste phenol resin.

[0048]

[0049] The above-mentioned compatibilizer serves to improve interfacial adhesion and compatibility between waste phenol resin and polypropylene. Since waste phenol resin and polypropylene have low chemical compatibility with each other, the adhesion at the interface may be weakened when the two materials are combined.

[0050] The above compatibilizer may be MA-g-PP. The above MA-g-PP is a form in which a maleic anhydride group is bonded to polypropylene, and this maleic anhydride group forms a polar bond with the hydroxyl group (-OH) of the phenol resin. This bond strengthens the interfacial adhesion between the phenol resin and polypropylene, playing an important role in improving the mechanical properties of the composite. The compatibilizer helps the waste phenol resin to be dispersed more uniformly within the composite material, thereby improving properties such as tensile strength and impact strength. In addition, the addition of the compatibilizer improves the overall properties of the composite material, and in particular, thermal properties such as heat resistance can also be improved.

[0051] In this step, the above compatibilizer may be included in an amount of 8 to 12 phr based on the above polypropylene. If the content of the compatibilizer is low, the interfacial adhesion between the waste phenol resin and polypropylene becomes insufficient, which may lead to a deterioration in mechanical properties. Furthermore, insufficient bonding at the interface results in reduced tensile strength and impact strength, and the dispersibility of the composite also decreases, making it highly likely that the materials will not mix uniformly. Conversely, if the content is high, an imbalance in the adhesion between PP and the waste phenol resin may occur, and mechanical properties may deteriorate. Additionally, excessive interaction between the materials may occur, which may have a negative effect on properties such as tensile strength or elongation. Therefore, even if the content of the compatibilizer exceeds 12 phr, the properties may not improve and may instead deteriorate.

[0052]

[0053] The above mixture may further include a step of processing it into the form of pellets or powder. This step involves forming the polypropylene composite into small bead-shaped particles so that they can be easily used in the molding process.

[0054] In this step, the mixture (or polypropylene composite) is placed into an extruder and heated to a molten state, and the molten mixture is extruded through a die in the shape of a long, thin thread while cooling, and then cut into small particle shapes using a pellet cutter.

[0055]

[0056] An automotive part according to an embodiment of the present invention comprises a polymer matrix and a polypropylene composite dispersed and disposed in said polymer matrix. The polypropylene composite is as described above.

[0057] The manufacturing of the above-mentioned automotive parts can be carried out through various molding processes. Injection molding is primarily used in the molding process, and pelletized polypropylene composites can be injected into an injection molding machine to form the desired shape of the automotive part. The polypropylene composite, heated to a high temperature, is injected into a mold and solidifies as it cools to form the final product.

[0058]

[0059] Example: Preparation of a polypropylene composite

[0060] Example 1 (WPR10C5): Polypropylene (PP) powder, MA-g-PP (Chemko, MP600PP) as a compatibilizer, and 100 mesh waste phenol resin was prepared by crushing the sprue / runner of a discarded novolak phenol compound from Shinheung Chemical and sieving it. 100 g of the above polypropylene was placed in a stirrer, and 5 phr of compatibilizer and 10 phr of waste phenol resin were added to the polypropylene and stirred to prepare a polypropylene composite.

[0061]

[0062] Example 2 (WPR20C5): Prepared in the same manner as Example 1, except that 20 phr of waste phenol resin was added to polypropylene.

[0063]

[0064] Example 3 (WPR30C5): Prepared in the same manner as Example 1, except that 30 phr of waste phenol resin was added to polypropylene.

[0065]

[0066] Example 4 (WPR30C7): Prepared in the same manner as Example 1, except that 7 phr of compatibilizer was added to polypropylene and 30 phr of waste phenol resin was added to polypropylene.

[0067]

[0068] Example 5 (WPR30C10): Prepared in the same manner as Example 1, except that 10 phr of compatibilizer was added to polypropylene and 30 phr of waste phenol resin was added to polypropylene.

[0069]

[0070] Comparative Example 1 (WPR10C0): Prepared in the same manner as Example 1, except that no compatibilizer was added and 10 phr of waste phenol resin was added to polypropylene.

[0071]

[0072] Comparative Example 2 (WPR20C0): Prepared in the same manner as Example 1, except that no compatibilizer was added and 20 phr of waste phenol resin was added to polypropylene.

[0073]

[0074] Comparative Example 3 (WPR30C0): Prepared in the same manner as Example 1, except that no compatibilizer was added and 30 phr of waste phenol resin was added to polypropylene.

[0075]

[0076] In order to perform various experiments on the previously prepared examples and comparative examples and polypropylene, dog-bone shaped specimens of 165 mm X 12.5 mm X 3.2 mm were prepared according to ASTM D638 standards and rod specimens of 65 mm X 12.5 mm X 3.2 mm were prepared according to ASTM D256 standards using a vertical injection molding machine (Injection molding machine, Heunghwa Machinery Industry, HVM-25VS).

[0077]

[0078] Experimental Example: FTIR Analysis

[0079] FTIR analysis was performed on Examples 1 to 3, Comparative Examples 1 to 3, and Polypropylene (PP), and the results are shown in FIG. 2. Referring to FIG. 2, it can be seen that a red shift occurs in the OH peak upon the addition of the compatibilizer. This is because the maleic anhydride group of the compatibilizer and the hydroxyl group of the waste phenol resin form polar bonds, weakening the binding energy of the hydroxyl group and causing a peak to be observed at a low wavenumber. Through this, it can be seen that the Polypropylene and the waste phenol resin interacted with each other via the compatibilizer.

[0080]

[0081] Experimental Example: Measurement of Tensile Strength

[0082] Tensile strength was measured to confirm the effect of adding a compatibilizer. The tensile strength of Examples 1 to 3, Comparative Examples 1 to 3, and Polypropylene was measured according to the ASTM D638 method, and the measurement results are shown in Fig. 3. Referring to Fig. 3, the tensile strength decreased with the addition of waste phenol resin (Comparative Examples 1 to 3), but the tensile strength did not decrease when a compatibilizer was added (Examples 1 to 3).

[0083]

[0084] Experimental Example: Measurement of Flexural Modulus

[0085] To confirm the effect of adding a compatibilizer, the flexural modulus was measured. The flexural modulus of Examples 1 to 3, Comparative Examples 1 to 3, and Polypropylene was measured according to the ASTM D790 method, and the measurement results are shown in Fig. 4. Referring to Fig. 4, the flexural modulus increased with the addition of waste phenol resin (Comparative Examples 1 to 3), and this level was maintained even when a compatibilizer was added. In particular, Example 3, which contained 30 phr of waste phenol resin and a compatibilizer, showed the best flexural modulus.

[0086]

[0087] Experimental Example: Measurement of Tensile Strength

[0088] Tensile strength was measured to determine the optimal content of the compatibilizer. The tensile strengths of Examples 3 to 5, Comparative Example 3, and Polypropylene were measured in the same manner as previously tested, and the results are shown in Fig. 5. Referring to Fig. 5, the tensile strength of Example 5 is the best.

[0089]

[0090] Experimental Example: Measurement of Flexural Modulus

[0091] To determine the optimal content of the compatibilizer, the flexural modulus was measured. The flexural modulus of Examples 3 to 5, Comparative Example 3, and Polypropylene was measured in the same manner as previously tested, and the results are shown in Fig. 6. Referring to Fig. 6, the flexural modulus of Example 5 is the best.

[0092]

[0093] Experimental Example: Measurement of Elongation

[0094] Elongation was measured to determine the optimal content of the compatibilizer. The elongation of Examples 3 to 5, Comparative Example 3, and Polypropylene was measured according to the ASTM D638 method, and the results are shown in Fig. 7. Referring to Fig. 7, the elongation decreased with the addition of waste phenolic resin, and when the compatibilizer was added at 5 and 7 phr (Examples 3 and 4), the elongation actually decreased compared to the case where it was not added (Comparative Example 3). However, Example 5, in which the compatibilizer was added at 10 phr, showed a higher elongation than Comparative Example 3.

[0095]

[0096] Experimental Example: Measurement of Impact Strength

[0097] Impact strength was measured to determine the optimal content of the compatibilizer. The impact strength of Examples 3 to 5, Comparative Example 3, and Polypropylene was measured according to the ASTM D256 method, and the results are shown in Fig. 8. Referring to Fig. 8, the impact strength decreased with the addition of waste phenolic resin, and the impact strength improved when the compatibilizer was added (Examples 3 to 5) compared to when it was not added (Comparative Example 3). Example 5, in which the compatibilizer was added at a concentration of 10 phr, exhibited the best impact strength.

[0098]

[0099] The present invention is not limited by the embodiments described above and the attached drawings, but is intended to be limited by the appended claims. Accordingly, various substitutions, modifications, and changes may be made by those skilled in the art within the scope of the technical concept of the present invention as described in the claims, without departing from the technical spirit of the invention, and such are also to be considered to fall within the scope of the present invention.

[0100]

[0101]

Claims

1. A step of preparing waste phenol resin, and A step comprising mixing polypropylene (PP), a compatibilizer, and the waste phenol resin to prepare a mixture, Method for manufacturing a polypropylene composite.

2. In Paragraph 1, The step of preparing the above waste phenol resin is to prepare the waste phenol resin by crushing the phenol resin and sieving it through a sieve of 160 to 180 mesh. Method for manufacturing a polypropylene composite.

3. In Paragraph 1, In the step of preparing the above mixture, comprising 8 to 12 phr of the compatibilizer based on the polypropylene, Method for manufacturing a polypropylene composite.

4. In Paragraph 1, In the step of preparing the above mixture, comprising 25 to 35 phr of the waste phenol resin based on the polypropylene, Method for manufacturing a polypropylene composite.

5. Polypropylene (PP), compatibilizer and waste phenol resin, comprising Polypropylene composite.

6. In Paragraph 5, Manufactured by the method of paragraph 1, Polypropylene composite.

7. In Paragraph 5, Comprising 8 to 12 phr of the compatibilizer based on the above polypropylene, Polypropylene composite.

8. In Paragraph 5, Comprising 25 to 35 phr of the waste phenol resin based on the above polypropylene, Polypropylene composite.

9. comprising a polymer matrix and a polypropylene composite dispersed and disposed in the polymer matrix, The above polypropylene composite is that of claim 5, Car parts.

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