Compounding composition comprising recycled polypropylene resin

Abstract

The present invention relates to a compounded composition comprising a recycled polypropylene resin. The compounded composition comprising a recycled polypropylene resin of the present invention can improve the appearance quality of an injection-molded product without causing a phenomenon of glass fiber aggregation because the flowability is not reduced during the injection process. In addition, the compounded composition comprising a recycled polypropylene resin of the present invention can still exhibit excellent mechanical properties despite a high content of the recycled polypropylene resin.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2024-0175261, filed with the Korean Intellectual Property Office on November 29, 2024, entitled "A Compound Composition Including Recycled Polypropylene Resin", the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This invention relates to a compound composition comprising recycled polypropylene resin. Background Technology

[0004] Polypropylene resin is a versatile material known for its excellent chemical resistance, weather resistance, ease of processing, and lightweight properties, which facilitate its manufacture in various forms, including injection-molded products, films, and blow-molded products. These properties make it widely used in multiple industries, such as electrical components, automotive manufacturing, and building materials. Recently, with the increasing research aimed at reducing the weight of hydrogen fuel cell vehicles and improving fuel efficiency, there has been a clear shift towards replacing traditional metal components in automobiles with polypropylene resin, thereby optimizing vehicle design performance and sustainability.

[0005] Given the growing environmental concerns, particularly regarding carbon dioxide (CO2) emissions, there is a growing need for the development of recycled plastics that can be efficiently recycled and utilize post-consumer polypropylene resins. This shift towards recycling not only addresses sustainability challenges but also contributes to reducing the overall carbon footprint associated with plastic production and disposal by minimizing waste and conserving resources, thus promoting a circular economy.

[0006] However, recycled polypropylene resin oxidizes after prolonged use in daily applications and is subjected to additional thermal stress during reprocessing, resulting in a decrease in its mechanical properties, heat resistance, and dimensional stability compared to virgin polypropylene resin. To mitigate these drawbacks and improve the performance of recycled materials, a common practice is to blend virgin and recycled polypropylene resins, thereby improving the overall quality and functionality of the resulting recycled plastics.

[0007] For composites comprising blends of polypropylene resin and glass fiber, the differing flow properties of virgin and recycled polypropylene resins present a significant challenge. This flow mismatch can lead to difficulty in achieving uniform distribution of glass fibers within the matrix, resulting in fiber aggregation on the surface during injection molding. Therefore, the amount of recycled polypropylene resin may be limited, as excess can exacerbate these flow problems and negatively impact the overall properties and mechanical properties of the composite.

[0008] To address these challenges, this invention proposes a compounding composition that effectively combines virgin and recycled polypropylene resins with an optimized melt flow index. This innovative formulation improves flowability and ensures consistent mechanical properties, even with the addition of a high percentage of recycled content. By carefully balancing the properties of the two resin types, the composition not only improves processing efficiency but also maintains the integrity and performance of the final product. Summary of the Invention

[0009] According to one aspect of the present invention, a compound composition comprising recycled polypropylene resin is provided, which has excellent injection molding appearance quality.

[0010] In this embodiment, a compound composition comprising recycled polypropylene resin is disclosed, which exhibits excellent mechanical properties during injection molding even when the recycled polypropylene resin content is high.

[0011] In this embodiment, a compound composition comprising recycled polypropylene resin is disclosed herein, which can be applied in the field of green technology, such as manufacturing chimney vent filter covers for hydrogen fuel cell vehicles.

[0012] In this embodiment, a compound composition is disclosed herein comprising: polypropylene resin, glass fiber, and additives, wherein the polypropylene resin comprises virgin polypropylene resin with a melt flow index of 60 g / 10 min to 100 g / 10 min and recycled polypropylene resin with a melt flow index of 80 g / 10 min to 100 g / 10 min, as measured according to ASTM D1238 at 230°C and a load of 2.16 kg.

[0013] According to one embodiment of the present invention, the polypropylene resin may comprise virgin polypropylene resin and recycled polypropylene resin in a weight ratio of 1:0.1 to 1:3.

[0014] According to one embodiment of the present invention, the original polypropylene resin may include homopolymer polypropylene resin, ethylene-propylene copolymer resin, or a combination thereof.

[0015] According to one embodiment of the present invention, the recycled polypropylene resin may include homopolymer polypropylene resin, ethylene-propylene copolymer resin, ethylene-octene copolymer resin, or a combination thereof.

[0016] According to one embodiment of the present invention, the cross-sectional diameter of the glass fiber can be from 12 μm to 20 μm, and the average length can be from 6 mm to 20 mm.

[0017] According to one embodiment of the present invention, glass fibers can be surface modified by a silane coupling agent.

[0018] According to one embodiment of the invention, the additive may include at least one selected from compatibilizers, impact modifiers, heat resistant agents, colorants, release agents, and nucleating agents.

[0019] According to one embodiment of the invention, based on the total weight of the compounded composition, the compounded composition may include 50 wt% to 60 wt% of polypropylene resin, 20 wt% to 50 wt% of glass fiber, and 5 wt% to 20 wt% of additives.

[0020] According to one embodiment of the present invention, the Izod impact strength of the compound composition can be 10 kJ / m. 2 Up to 50kJ / m 2 As measured according to ISO 180.

[0021] According to one embodiment of the invention, the heat distortion temperature of the compound composition can be from 150°C to 200°C, as measured according to ISO 75.

[0022] According to another aspect of the present invention, an injection-molded product is provided, which is formed from the compounding composition described in the present invention.

[0023] According to one embodiment of the invention, a compound composition comprising recycled polypropylene resin can improve the appearance quality of injection-molded products without causing glass fiber aggregation, because the fluidity is not reduced during injection molding.

[0024] According to one embodiment of the invention, although the content of recycled polypropylene resin is high, the compound composition including recycled polypropylene resin can still exhibit excellent mechanical properties. Attached Figure Description

[0025] Figure 1 These are photographs evaluating the appearance of injection-molded products manufactured using the compounding compositions of (a) Example 1, (b) Example 2 and (c) Example 3 according to the present invention.

[0026] Figure 2 These are photographs evaluating the appearance of injection-molded products manufactured using the compounding compositions according to (a) Comparative Example 2 and (b) Comparative Example 6. Detailed Implementation

[0027] The present invention will be described in more detail below. However, the following examples or embodiments are provided for reference only in explaining the invention in detail, and the invention is not limited thereto and can be implemented in various forms.

[0028] Furthermore, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0029] The terminology used in this specification is for the purpose of effectively describing specific embodiments only and is not intended to limit the invention.

[0030] Furthermore, as used in the specification and claims, the singular form may be intended to include the plural form unless the context clearly specifies otherwise.

[0031] Furthermore, all units used in this specification unless otherwise specified are based on weight. For example, % or proportion means wt% or weight ratio, and wt% means wt% of any component in the whole composition, unless otherwise defined.

[0032] Furthermore, unless otherwise expressly stated, when any part “includes” any ingredient, it should be understood that it also includes another ingredient, rather than excluding another ingredient.

[0033] Furthermore, the numerical range used in this invention may include a lower limit and an upper limit, as well as all values ​​within that range, increments logically derived from the shape and width of the defined range, all double-defined values, and all possible combinations of the upper and lower limits of numerical ranges defined in different shapes. Unless otherwise specifically defined in the specification of this invention, values ​​that may exceed the numerical range due to experimental errors or numerical rounding are also included within the defined numerical range.

[0034] The invention will be described in more detail below.

[0035] This invention relates to a compounding composition comprising polypropylene resin, glass fiber, and additives, wherein the polypropylene resin includes virgin polypropylene resin and recycled polypropylene resin. By organically combining virgin polypropylene resin and recycled polypropylene resin satisfying a limited range of melt flow indices with glass fiber, the compounding composition of this invention can exhibit excellent injection molding appearance quality, and the mechanical properties are not reduced even when the content of recycled polypropylene resin is high.

[0036] The present invention provides a compounding composition comprising polypropylene resin, glass fiber, and additives, wherein the polypropylene resin comprises virgin polypropylene resin and recycled polypropylene resin.

[0037] In one embodiment of the invention, the lower limit of the melt flow index of the virgin polypropylene resin, measured according to ASTM D1238 at 230°C and a load of 2.16 kg, can be 60 g / 10 min or more, 65 g / 10 min or more, 70 g / 10 min or more, 75 g / 10 min or more, or 80 g / 10 min or more, and the upper limit can be 100 g / 10 min or less, 95 g / 10 min or less, or 90 g / 10 min or less. When this range is met, the virgin polypropylene resin itself exhibits excellent heat resistance and mechanical properties, and good impregnation properties with long-fiber glass fibers, thereby ensuring that the compounded composition has excellent physical properties.

[0038] In one embodiment of the invention, the lower limit of the melt flow index of the recycled polypropylene resin, measured according to ASTM D1238 at 230°C and a load of 2.16 kg, can be 80 g / 10 min or more, 82 g / 10 min or more, 85 g / 10 min or more, or 87 g / 10 min or more, and the upper limit can be 100 g / 10 min or less, 95 g / 10 min or less, or 90 g / 10 min or less. When this range is met, glass fiber damage due to the characteristics of recycled polypropylene resin (which inevitably includes impurities) can be suppressed, deterioration of appearance quality due to glass fiber agglomeration can be prevented, and excellent heat resistance and mechanical properties can be ensured.

[0039] In one embodiment of the invention, the compounding composition may include virgin polypropylene resin and recycled polypropylene resin in a weight ratio of 1:0.5 to 1:5, specifically a weight ratio of 1:1 to 1:3. When this range is met, the content of recycled polypropylene resin can be maximized and the injection-molded products using the compounding composition can achieve excellent mechanical properties.

[0040] According to one embodiment of the present invention, the original polypropylene resin may include homopolymer polypropylene resin, ethylene-propylene copolymer resin, or a combination thereof.

[0041] According to one embodiment of the present invention, the recycled polypropylene resin may include homopolymer polypropylene resin, ethylene-propylene copolymer resin, ethylene-octene copolymer resin, or a combination thereof.

[0042] According to one embodiment of the invention, the cross-sectional diameter of the glass fiber can be from 12 μm to 20 μm, specifically from 15 μm to 20 μm, and the average length can be from 6 mm to 20 mm, specifically from 9 mm to 11 mm. When this range is met, the mechanical properties of the compound are excellent.

[0043] According to one embodiment of the present invention, glass fibers can be surface-modified using a silane coupling agent. Surface modification can improve the interfacial adhesion between the glass fibers and the polypropylene resin, thereby ensuring that the compounded composition has excellent mechanical properties and heat resistance.

[0044] In one embodiment of the present invention, the silane coupling agent may be a silane coupling agent having organic functional groups (e.g., aminosilane and glycidylsilane), but is not limited thereto, as long as the purpose of the present invention can be achieved.

[0045] According to one embodiment of the invention, the additive may include at least one selected from compatibilizers, impact modifiers, heat resistant agents, colorants, release agents, and nucleating agents.

[0046] According to one embodiment of the present invention, the compatibilizer may be a homopolymer polypropylene grafted with maleic anhydride, an ethylene-propylene copolymer, an ethylene-octene copolymer, or a combination thereof.

[0047] In one embodiment of the invention, the compatibilizer content can be from 1.0 wt% to 5.0 wt%, specifically from 2.0 wt% to 4.0 wt%, and more specifically from 2.5 wt% to 3.0 wt%, based on the total weight of the compounded composition. When this range is met, the compatibility between the polypropylene resin and the glass fiber can be improved, thereby improving the mechanical properties of the compounded composition.

[0048] In one embodiment of the present invention, the use of impact-resistant agents is not limited, as long as they are known in the art.

[0049] In one embodiment of the invention, the content of the impact-resistant agent can be from 0.5 wt% to 3.0 wt%, specifically from 1.0 wt% to 2.5 wt%, and more specifically from 1.5 wt% to 2.0 wt%, based on the total weight of the compounded composition. When this range is met, the impact-resistant agent can be uniformly dispersed in the composition without reducing the mechanical properties of the compounded composition, thereby effectively improving the impact resistance.

[0050] In one embodiment of the present invention, the heat resistant agent may include phenolic heat resistant agents, phosphorus heat resistant agents, or combinations thereof.

[0051] In one embodiment of the invention, the content of the heat-resistant agent can be from 0.1 wt% to 2.0 wt%, specifically from 0.5 wt% to 1.5 wt%, and more specifically from 0.8 wt% to 1.0 wt%, based on the total weight of the compound. When this range is met, the heat resistance of the compound can be effectively improved.

[0052] In one embodiment of the present invention, the use of colorants is not limited, as long as they are known in the art.

[0053] In one embodiment of the present invention, the content of the colorant may be from 0.5 wt% to 2.0 wt%, specifically from 1.0 wt% to 1.5 wt%, based on the total weight of the compounded composition, but is not limited thereto, as long as the purpose of the present invention can be achieved.

[0054] In one embodiment of the invention, the polypropylene resin content in the compounding composition can be from 50 wt% to 60 wt%, specifically from 53 wt% to 55 wt%, based on the total weight of the compounding composition. When this range is met, the compounding composition exhibits excellent flowability, resulting in excellent appearance quality of the injection-molded product and ensuring excellent mechanical properties.

[0055] In one embodiment of the invention, the glass fiber content in the compound composition can be from 20 wt% to 50 wt%, specifically from 35 wt% to 45 wt%, based on the total weight of the compound composition. When this range is met, the tensile strength and flexural strength of the compound composition are not reduced, and the reduction in injection molding performance due to surface defects and reduced flowability during molding can be prevented.

[0056] In one embodiment of the present invention, the content of additives in the compounding composition may be from 5 wt% to 20 wt% based on the total weight of the compounding composition, but is not limited thereto, as long as the purpose of the present invention can be achieved.

[0057] In one embodiment of the invention, the lower limit of the Izod impact strength of the compound, measured according to ISO 180, can be 10 kJ / m. 2 or above, 11kJ / m 2 or above, 12kJ / m 2 or above, 13kJ / m 2 or above, 14kJ / m 2 or above, 15kJ / m 2 Or above, with an upper limit of 50 kJ / m³ (not limited to). 2 Or the following.

[0058] In one embodiment of the invention, the lower limit of the heat distortion temperature of the compound composition, as measured according to ISO 75, may be 150°C or above, 152°C or above, 153°C or above, or 155°C or above, and the upper limit is not limited to 200°C or below.

[0059] In one embodiment of the invention, the compounding composition can be prepared by melt mixing polypropylene resin, glass fiber and additives.

[0060] In one embodiment of the invention, the melt mixing can be carried out at a temperature of 230°C to 300°C, specifically 250°C to 270°C. When this range is met, the thermal decomposition or volatilization of additives or polypropylene resin contained in the compound composition can be suppressed, and the polypropylene resin exhibits sufficient impregnation properties. Furthermore, the melt mixing method and apparatus are not limited, as long as they are commonly used in the art.

[0061] Furthermore, the present invention provides an injection-molded product formed from the compounding composition described herein. The injection molding method for forming the injection-molded product is well known to those skilled in the art to which this invention pertains.

[0062] In one embodiment of the invention, the injection-molded product can be used as an engineered component of a hydrogen fuel cell vehicle, specifically as a chimney vent filter cover, but is not limited thereto.

[0063] Preferred embodiments and comparative examples of the present invention will be described below. However, the following embodiments are merely preferred embodiments of the present invention, and the present invention is not limited to the following embodiments.

[0064] Example

[0065] In the following text, the specifications of the components commonly used in the examples and comparative examples are as follows.

[0066] (A) Use virgin polypropylene resin (manufacturer: Polymirae Co., Ltd., product name: HP480S, melt flow index: 80g / 10min).

[0067] (B) Glass fiber

[0068] Glass fiber (manufacturer: Owens Corning Co., Ltd., product name: SE4121, cross-sectional diameter: 15 to 20 μm, length: 10 mm).

[0069] (C) Compatibilizer

[0070] Polypropylene modified with maleic anhydride (manufacturer: Woosung Chemical Co., Ltd., product name: NB1620, maleic anhydride grafting rate: 1.0 wt%).

[0071] (D) Impact-resistant agent

[0072] Use polyolefin elastomer (manufacturer: Dow Chemical Co., Ltd., product name: Engage 8200).

[0073] (E) Heat resistant agent

[0074] Use heat resistant agent (manufacturer: Woosung Chemical Co., Ltd., product name: NB1020).

[0075] (F) Coloring agent

[0076] Use colorant (manufacturer: Doonam Chemical Co., Ltd., product name: MPP0406).

[0077] Example 1

[0078] Based on the total weight of the composition, 20 wt% of recycled polypropylene resin (manufacturer: Greenpole Co., Ltd., product name: HB100GP, melt flow index: 90 g / 10 min), 33.4 wt% of virgin polypropylene resin, 2.7 wt% of compatibilizer, 1.8 wt% of impact modifier, 0.9 wt% of heat resistant agent and 1.2 wt% of colorant were mixed using a TEX-44 twin-helix mixer with a diameter of 44 mm, and 40 wt% of glass fiber provided by roving was impregnated into the mixture to produce long fiber reinforced resin particles with a length of 10 mm.

[0079] Examples 2 and 3

[0080] The granules were manufactured in the same manner as in Example 1, except that recycled polypropylene resin and virgin polypropylene resin were added as described in Table 1 below.

[0081] Comparative Example 1

[0082] The granules were manufactured in the same manner as in Example 1, except that the melt flow index of the recycled polypropylene resin was 10 g / 10 min.

[0083] Comparative Example 2

[0084] The granules were manufactured in the same manner as in Example 2, except that the melt flow index of the recycled polypropylene resin was 10 g / 10 min.

[0085] Comparative Example 3

[0086] The granules were manufactured in the same manner as in Example 1, except that the melt flow index of the recycled polypropylene resin was 20 g / 10 min.

[0087] Comparative Example 4

[0088] The granules were manufactured in the same manner as in Example 2, except that the melt flow index of the recycled polypropylene resin was 20 g / 10 min.

[0089] Comparative Example 5

[0090] The granules were manufactured in the same manner as in Example 2, except that different types of recycled polypropylene resin were mixed to achieve a melt flow index of 50 g / 10 min.

[0091] Comparative Example 6

[0092] The granules were manufactured in the same manner as in Example 1, except that no recycled polypropylene resin was added, but only 53.4 wt% of virgin polypropylene resin was added.

[0093] The amounts of each component added in the examples and comparative examples are shown in Table 1 below.

[0094] Physical property measurement methods

[0095] The physical properties of samples prepared from the compounded compositions of the injection molding examples and comparative examples were evaluated using the following physical property measurement methods. The results are shown in Table 1 and... Figure 1 and Figure 2 middle.

[0096] (1) Tensile strength (unit: MPa): The tensile strength of a 4.0 mm thick sample was measured at 100 mm / min according to ISO 527.

[0097] (2) Bending strength (unit: MPa): The bending strength of a 4.0 mm thick sample was measured at 5.8 mm / min according to ISO 178.

[0098] (3) Notched Izod impact strength (unit: kJ / m) 2 ): According to ISO 180, the notched Izod impact strength of a 4.0 mm thick sample is measured.

[0099] (4) Heat distortion temperature (unit: °C): The heat distortion temperature (HDT) is measured according to ISO 75 under the conditions of a load of 1.80 MPa and a heating rate of 2 °C / min.

[0100] (5) Appearance evaluation: Identify the number of fiber aggregates with a length of 0.3 cm or more that are visible to the naked eye on the surface of the injection molded sample of 400 mm × 250 mm × 2 mm.

[0101] [Table 1]

[0102]

[0103] From Table 1 and Figure 1 It can be seen that adding high-flowability recycled polypropylene resin with a melt flow index of 90 g / 10 min to Examples 1 to 3 improved flowability, resulting in no glass fiber aggregation on the product surface during injection molding. On the other hand, from Table 1 above and... Figure 2 It can be seen that when conventional low-flow recycled polypropylene resin (e.g., Comparative Examples 1 to 4) or medium-flow recycled polypropylene resin (e.g., Comparative Example 5) is added, the flowability does not match that of the virgin polypropylene resin, resulting in reduced flowability and the aggregation of glass fibers on the outside during injection molding. This confirms that the flowability of the virgin polypropylene resin and the recycled polypropylene resin can be matched, thereby achieving excellent mechanical properties and a high recycled material content in the compound.

[0104] Meanwhile, the mechanical properties of the embodiments were generally inferior to those of Comparative Example 6, which used only virgin polypropylene resin. Therefore, a component evaluation was performed to confirm whether the compounded compositions of the embodiments could be used to manufacture actual automotive engineered parts. Specifically, a chimney vent filter cover was manufactured using the compounded composition of Example 3 (which had the lowest mechanical properties among the embodiments), and then the test items listed in Table 2 below were evaluated.

[0105] [Table 2]

[0106]

[0107] As a result of the test items listed in Evaluation Table 2, it can be confirmed that the chimney vent filter cover was not cracked, severely deformed (which would prevent assembly), or damaged, thus ensuring the physical performance that can be applied to actual automotive components.

[0108] Therefore, it can be seen that the compounding composition according to the present invention can reduce material costs by including recycled resin, give the finished product an environmentally friendly image when used, and replace polyamide materials with excellent mechanical properties.

[0109] The features, structures, effects, etc., described in the above embodiments are included in at least one embodiment of the present invention, but are not necessarily limited to one embodiment. Furthermore, the features, structures, effects, etc., shown in the various embodiments can be combined or modified by those skilled in the art to which that embodiment pertains, or even in other embodiments. Therefore, the content related to these combinations and modifications should be interpreted as being covered within the scope of the present invention.

Claims

1. A compounding composition comprising: Polypropylene resin, glass fiber, and additives, wherein the polypropylene resin comprises virgin polypropylene resin with a melt flow index of 60 g / 10 min to 100 g / 10 min and recycled polypropylene resin with a melt flow index of 80 g / 10 min to 100 g / 10 min, as measured according to ASTM D1238 at 230°C and 2.16 kg load.

2. The compounding composition according to claim 1, wherein the polypropylene resin comprises the virgin polypropylene resin and the recycled polypropylene resin in a weight ratio of 1:0.5 to 1:

5.

3. The compounding composition according to claim 1, wherein the original polypropylene resin comprises homopolymer polypropylene resin, ethylene-propylene copolymer resin, or a combination thereof.

4. The compounding composition according to claim 1, wherein the recycled polypropylene resin comprises homopolymer polypropylene resin, ethylene-propylene copolymer resin, or a combination thereof.

5. The compounding composition according to claim 1, wherein the glass fiber has a cross-sectional diameter of 12 μm to 20 μm and an average length of 6 mm to 20 mm.

6. The compounding composition according to claim 1, wherein the glass fiber is surface modified by a silane coupling agent.

7. The compounding composition according to claim 1, wherein the additive comprises at least one selected from compatibilizers, impact modifiers, heat resistant agents, colorants, release agents, and nucleating agents.

8. The compounding composition according to claim 1, wherein, based on the total weight of the compounding composition, the compounding composition comprises 50 wt% to 60 wt% of the polypropylene resin, 20 wt% to 50 wt% of the glass fiber, and 5 wt% to 20 wt% of the additive.

9. The compound composition according to claim 1, wherein the Izod impact strength of the compound composition is 10 kJ / m. 2 Up to 50kJ / m 2 As measured according to ISO 180.

10. The compounding composition according to claim 1, wherein the heat distortion temperature of the compounding composition is 150°C to 200°C, as measured according to ISO 75.

11. An injection-molded product formed from a compound composition according to any one of claims 1 to 10.

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