Polypropylene resin composition and molded product comprising same

Abstract

The present invention relates to a polypropylene resin composition and a molded product comprising the same, and more specifically, to a polypropylene resin composition which can prevent performance deterioration due to moisture. The polypropylene resin composition has low surface energy, and thus can improve chemical stability to external factors. In addition, a molded product comprising the polypropylene resin composition may have low ion elution ability (which may be an important requirement), and may achieve high weight reduction.

Description

Technical Field

[0001] The present invention relates to a polypropylene resin composition and a molded product comprising the same. Background Art

[0002] Typically, a fuel cell electric vehicle includes a fuel cell stack, an air supply device, and a thermal management system (TMS). The fuel cell stack uses hydrogen and oxygen as reaction gases to generate electricity and discharges heat and water as byproducts. In order to prevent the temperature of the fuel cell stack from rising, a cooling device must be provided.

[0003] The ion filter reduces the conductivity of the coolant supplied to the fuel cell stack to a specified level or lower by filtering out ions contained in the coolant. By removing ions from the coolant, the fuel cell stack can be prevented from leaking current through the coolant, and thus, the electrical stability of the vehicle can be improved.

[0004] Ion filters currently mainly use polyamide resin (PA66-GF55), which is expensive and shows a continuously deteriorating performance, and elutes ions when it is exposed to a high-temperature coolant, thereby increasing the conductivity of the coolant.

[0005] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the relevant technology that is already known to one of ordinary skill in the art in this country. Summary of the invention

[0006] The present invention is made to solve the above-mentioned problems associated with the related art, and an object of the present invention is to provide a polypropylene resin composition having stable properties.

[0007] An ion filter which is a molded product comprising a polypropylene resin composition has price competitiveness as well as chemical resistance, water resistance, and low ion elution ability.

[0008] In one aspect, the present invention provides a polypropylene resin composition comprising a polypropylene resin, a fiber reinforcement agent and a surface modifier.

[0009] In a preferred embodiment, the amount of the fiber reinforcement may be 40 parts by weight to 55 parts by weight based on 100 parts by weight of the polypropylene resin.

[0010] In another preferred embodiment, the amount of the surface modifier may be 0.1 parts by weight to 1 parts by weight based on 100 parts by weight of the polypropylene resin.

[0011] In yet another preferred embodiment, the number average molecular weight (Mn) of the polypropylene resin may be in the range of 15,000 g / mol to 30,000 g / mol.

[0012] In still another preferred embodiment, the polypropylene resin may include at least one selected from the group consisting of a polypropylene homopolymer and an ethylene-propylene copolymer.

[0013] In still another preferred embodiment, the polypropylene resin may have a melt index (MI) measured at a temperature of 230° C. and a load of 2.16 kg, of 30 to 50 g / 10 min.

[0014] In a further preferred embodiment, the fiber reinforcement may include at least one selected from glass fiber, carbon fiber, graphite fiber, metal fiber, basalt fiber, cotton fiber, wool fiber, silk fiber, aramid fiber, polyacrylonitrile (PAN) fiber, arylate fiber, polyetheretherketone (PEEK) fiber, nylon fiber, polyethylene terephthalate (PET) fiber.

[0015] In another further preferred embodiment, the length of the fiber reinforcement may be 6 mm to 25 mm.

[0016] In yet a further preferred embodiment, the diameter of the fiber reinforcement may be 12 μm to 20 μm.

[0017] In yet another further preferred embodiment, the surface modifier may include at least one selected from the group consisting of a silicon-based surface modifier, a wax-based surface modifier, and a stearate-based surface modifier.

[0018] In yet another further preferred embodiment, the polypropylene resin composition may further comprise an additive, wherein the additive comprises at least one selected from the group consisting of a compatibilizer, an impact resistant agent and a heat resistant agent.

[0019] In yet another further preferred embodiment, the polypropylene resin composition may include a compatibilizer, and the compatibilizer may include at least one selected from the group consisting of a polypropylene homopolymer, an ethylene-propylene copolymer, and an ethylene-octene copolymer.

[0020] In yet another further preferred embodiment, the polypropylene resin composition may include a compatibilizer, and the compatibilizer may be grafted with 0.8 wt% to 1.2 wt% of maleic anhydride, based on the total weight of the compatibilizer.

[0021] In another further preferred embodiment, the polypropylene resin composition may include a compatibilizer, wherein the amount of the compatibilizer may be 1 to 10 parts by weight based on 100 parts by weight of the polypropylene resin.

[0022] In yet another further preferred embodiment, the polypropylene resin composition may include an impact resistant agent, wherein the amount of the impact resistant agent may be 1 to 5 parts by weight based on 100 parts by weight of the polypropylene resin.

[0023] In yet another further preferred embodiment, the polypropylene resin composition may include a heat-resistant agent, and the heat-resistant agent may include at least one selected from the group consisting of a phenolic heat-resistant agent and a phosphate heat-resistant agent.

[0024] In yet another further preferred embodiment, the polypropylene resin composition may include a heat-resistant agent, wherein the amount of the heat-resistant agent may be 0.1 to 1 parts by weight based on 100 parts by weight of the polypropylene resin.

[0025] In yet another further preferred embodiment, the polypropylene resin composition may have: a tensile strength of 125 MPa or more according to ISO 527, a flexural strength of 170 MPa or more according to ISO 178, a thermal conductivity of 26 kJ / m according to ISO 180, 2 or higher impact strength, and a heat distortion temperature of 158° C. or higher under a load of 1.8 MPa according to ISO 75.

[0026] In another aspect, the present invention provides a molded product comprising the polypropylene resin composition.

[0027] In a preferred embodiment, the molded product may further comprise an ion filter.

[0028] In another preferred embodiment, the molded product may have an ion eluting ability of 0.8 ppm or less.

[0029] Other aspects and embodiments of the invention are discussed below.

[0030] The above features and other features of the present invention are discussed below. DETAILED DESCRIPTION

[0031] The above-mentioned purpose, other purposes, advantages and features of the present invention will become apparent from the description of the embodiments given below. However, the present invention is not limited to the embodiments disclosed herein, but can be implemented in various different forms. The embodiments are provided to make the description of the present invention thorough and to fully convey the scope of the present invention to those skilled in the art.

[0032] In the following description of the embodiment, terms such as "first" and "second" may be used to describe various elements, but do not limit these elements. These terms are only used to distinguish one element from other elements. For example, without departing from the scope and spirit of the present invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. Singular expressions may encompass plural expressions unless they have significantly different contextual meanings.

[0033] In the following description of the embodiment, terms such as "comprise", "include" and "have" should be interpreted as indicating the presence of the features, numbers, steps, operations, elements or parts or combinations thereof stated in the description, and do not exclude the presence of one or more other features, numbers, steps, operations, elements, parts or combinations thereof, or the possibility of adding them. In addition, it should be understood that when a component (such as a layer, film, region or plate) is referred to as being "on" another component, the component can be "directly on" the other component, or other components can be inserted between the two components. In the same way, it should be understood that when a component (such as a layer, film, region or plate) is referred to as being "below" another component, the component can be "directly below" the other component, or other components can be inserted between the two components.

[0034] All numbers, values ​​and / or expressions used in the specification to represent the amount of components, reaction conditions, polymer compositions and blends are approximate values, which reflect the various uncertainties in the measurements generated when these values ​​are obtained from essentially different objects, so it should be understood that unless otherwise stated, they are modified by the term "about". In addition, it should be understood that if a numerical range is disclosed in the specification, the range includes all continuous values ​​from the minimum value to the maximum value of the range, unless otherwise stated. In addition, if such a range involves integers, the range includes all integers from the minimum integer to the maximum integer, unless otherwise stated.

[0035] In recent years, the automotive industry has been committed to various developments in order to solve environmental issues as a social problem and to improve vehicle efficiency. As a way to solve environmental issues, traditionally mainstream internal combustion engine vehicles are being replaced by electric vehicles and fuel cell electric vehicles (FCEVs). FCEVs are driven differently from traditional internal combustion engine vehicles and are therefore equipped with new components that have not been used traditionally.

[0036] The ion filter, which is one of the components of FCEV, is a core component for removing eluted ions used in FCEV from the coolant. The ion filter is a consumable, and therefore, as the amount of ions eluted in the coolant increases, the replacement cycle of the ion filter becomes faster (shortened), and thus, the replacement cycle of the ion filter may become faster and the cost of replacing the ion filter may increase. Therefore, from the perspective of marketability and cost, it is important to reduce the amount of ions to be eluted in the coolant in advance, and therefore, not only the materials used for the thermal management system (TMS) but also all the components that are in direct contact with the coolant should have low ion elution capabilities.

[0037] However, the materials currently used in ion filters are not sufficient to meet the low ion elution capacity. The parts in contact with antifreeze in internal combustion engine vehicles do not have high ion elution capacity, but all parts of fuel cell electric vehicles should have minimized ion elution capacity, so it is difficult to solve such ion elution problems using conventional materials.

[0038] Conventionally only metallic materials such as steel or aluminum are used, but such materials lead to a potential risk of corrosion and further to ion elution in the event of corrosion.

[0039] In addition, the polyamide resin PA66-GF55 currently being used contains 30-40% by weight of short glass fibers having a length of 2 mm to 3 mm, and thus can have high thermal stability, but has disadvantages in that due to the properties of polyamide 66 (PA66), when the product is exposed to water, the performance of the product deteriorates, and since PA66 with a relatively low viscosity (which is a modified polyamide resin) is used, high fluidity required for optimizing the productivity of injection molding molds cannot be obtained.

[0040] That is, the corresponding parts of conventional internal combustion engine vehicles use modified polyamide resins with high thermal stability because the temperature of the cooling fluid is very high due to the heat generated by the internal combustion engine. However, in the case of fuel cell electric vehicles, the temperature of the generated heat is relatively low, so the temperature rise of the cooling fluid is relatively low, and a temperature environment in which ordinary polypropylene resin can be applied is created. In addition, when polypropylene resin is used, the corresponding product has less performance deteriorated by moisture and low surface energy, and thus the chemical stability to external factors can be increased. In addition, the corresponding product can have low ion elution ability (which is the most important requirement), and a high degree of lightweight can be achieved.

[0041] The polypropylene resin composition according to the present invention may include a polypropylene resin, a fiber reinforcement agent, and a surface modifier.

[0042] Hereinafter, each component of the polypropylene resin composition will be described in detail.

[0043] (A) Polypropylene resin

[0044] The polypropylene resin according to the present invention may refer to a thermoplastic resin including an aliphatic molecular chain.

[0045] The number average molecular weight (Mn) of the polypropylene resin may be 15,000 g / mol to 30,000 g / mol.

[0046] The polypropylene resin may include at least one selected from the group consisting of a polypropylene homopolymer, an ethylene-propylene copolymer, and a combination thereof.

[0047] The melt index (MI) of the polypropylene resin measured at a temperature of 230° C. and a load of 2.16 kg may be 30 g / 10 min to 50 g / 10 min. When the MI of the polypropylene resin is less than 30 g / 10 min, the polypropylene resin may exhibit poor impregnation and poor mechanical properties in the fiber reinforcement due to low fluidity due to the manufacturing nature of long fiber reinforced thermoplastics (LFT), and when the MI of the polypropylene resin exceeds 50 g / 10 min, the polypropylene resin may exhibit poor mechanical properties because the polypropylene resin itself deteriorates in performance due to its low molecular weight.

[0048] (B) Fiber reinforcement

[0049] The fiber reinforcement according to the present invention may include at least one selected from glass fiber, carbon fiber, graphite fiber, metal fiber, basalt fiber, cotton fiber, wool fiber, silk fiber, aramid fiber, polyacrylonitrile (PAN) fiber, arylate fiber, polyetheretherketone (PEEK) fiber, nylon fiber, polyethylene terephthalate (PET) fiber and combinations thereof, and preferably, the fiber reinforcement may be glass fiber.

[0050] The length of the fiber reinforcement may be from 6 mm to 25 mm, for example, from 7 mm to 20 mm, from 8 mm to 18 mm, or from 9 mm to 15 mm.

[0051] As a material currently used as an ion filter housing, a material containing a polyamide resin and 35% by weight of a short fiber reinforcement (glass fiber) with a length of 2mm-3mm is used. However, the above material is expensive, and when the material is exposed to a high-temperature coolant, the performance of the material continues to deteriorate, and the material elutes ions in the coolant, so the conductivity of the coolant increases. In the present invention, in order to solve these problems, a material containing a polypropylene resin and 30-70% by weight of a long fiber reinforcement (glass fiber) with a length of 6mm to 25mm is applied to give full play to its role based on stable performance under a mild use environment, and to achieve lightweight as well as chemical resistance, water resistance and low ion elution ability due to the change of the polymer resin.

[0052] The diameter of the fiber reinforcement may be 12 μm to 20 μm.

[0053] The amount of the fiber reinforcement can be 40 to 55 parts by weight, preferably 42.15 to 51.52 parts by weight, based on 100 parts by weight of the polypropylene resin. When the amount of the fiber reinforcement is less than 40 parts by weight, the tensile strength and flexural strength of the polypropylene resin composition may be reduced, and when the amount of the fiber reinforcement exceeds 55 parts by weight, the injection molding performance of the polypropylene resin composition may be reduced due to surface defects or reduced fluidity during molding.

[0054] The fiber reinforcement may be glass fiber, and the glass fiber may be of the E-glass roving type in which infinitely long glass fibers are wound. Preferably, the surface of the glass fiber may be coupled with silane to achieve interfacial adhesion with the final composition.

[0055] (C) Surface modifier

[0056] The surface modifier according to the present invention is used to enhance fluidity, thereby improving the surface quality of an injection-molded product including the polypropylene resin composition.

[0057] The surface modifier may include at least one selected from silicon-based surface modifiers, wax-based surface modifiers, stearate-based surface modifiers, and combinations thereof, and may be, for example, a silicon-based surface modifier.

[0058] The amount of the surface modifier may be 0.1 to 1 part by weight, preferably 0.44 to 0.66 parts by weight, based on 100 parts by weight of the polypropylene resin. When the amount of the surface modifier is less than 0.1 parts by weight, the surface modifier may hardly exhibit the effect of improving the surface quality of the injection molded product including the polypropylene resin composition, and when the amount of the surface modifier exceeds 1 part by weight, the surface modifier may act as an impurity, thereby reducing the mechanical properties of the polypropylene resin composition.

[0059] (D) Additives

[0060] The polypropylene resin composition according to the present invention may further include an additive, wherein the additive includes at least one selected from the group consisting of a compatibilizer, an impact resistant agent, a heat resistant agent, and a combination thereof.

[0061] Compatibilizers are used to improve the compatibility between polypropylene resin and fiber reinforcement.

[0062] The compatibilizer may include at least one selected from the group consisting of polypropylene homopolymer, ethylene-propylene copolymer, ethylene-octene copolymer, and combinations thereof.

[0063] The compatibilizer may be grafted with 0.8 wt % to 1.2 wt % of maleic anhydride based on 100 wt % of the compatibilizer.

[0064] Based on 100 parts by weight of the polypropylene resin, the amount of the compatibilizer can be 1 to 10 parts by weight, preferably 3.93 to 5.90 parts by weight. When the amount of the compatibilizer is less than 1 part by weight, it is difficult to improve the compatibility between the polypropylene resin and the fiber reinforcement, so the mechanical properties of the product may not be ideal, and when the amount of the compatibilizer exceeds 10 parts by weight, the excess compatibilizer exists as unreacted material, so the mechanical properties of the product may also be less ideal.

[0065] The impact resistance agent is used to improve the impact properties of the polypropylene resin composition.

[0066] Based on 100 parts by weight of the polypropylene resin, the amount of the impact-resistant agent may be 1 to 5 parts by weight, preferably 2.62 to 3.93 parts by weight. When the amount of the impact-resistant agent is less than 1 part by weight, the overall distribution of the impact-resistant agent may be poor, and thus it may be difficult to improve the impact properties of the polypropylene resin composition, and when the amount of the impact-resistant agent exceeds 5 parts by weight, the impact properties of the polypropylene resin composition may be improved, but the tensile strength, flexural strength and other mechanical properties of the polypropylene resin composition may be reduced.

[0067] The heat-resistant agent is used to improve the heat resistance of the polypropylene resin composition.

[0068] The heat-resistant agent may include at least one selected from the group consisting of a phenol-based heat-resistant agent, a phosphate-based heat-resistant agent, and a combination thereof.

[0069] The amount of the heat-resistant agent may be 0.1 to 1 part by weight, preferably 0.44 to 0.66 parts by weight, based on 100 parts by weight of the polypropylene resin. When the amount of the heat-resistant agent is less than 0.1 parts by weight, the heat-resistant agent may not show an effect of improving the heat resistance of the polypropylene resin composition, and when the amount of the heat-resistant agent exceeds 1 part by weight, the effect of improving the heat resistance of the polypropylene resin composition may not be significant, and thus the heat-resistant agent may not be economically feasible.

[0070] Furthermore, antioxidants, flame retardants, fluorescent whitening agents, plasticizers, thickeners, antistatic agents, mold release agents, pigments, nucleating agents or combinations thereof may be added to the polypropylene resin composition within the scope not contrary to the purpose of the present invention.

[0071] When manufacturing polypropylene resin composition, commonly used melt kneading method and device can be used.The specific example of the device used in melt kneading can be single screw extruder or twin screw extruder.When adopting single screw extruder or twin screw extruder to uniformly knead raw materials, polypropylene resin and heat-resistant agent can be fed in the inlet, thereby realize uniform kneading effect by the shearing force of screw in extruder.In order to reduce the volatilization of additive and optimize the performance of composition in melt kneading, the retention time of raw materials in equipment (for example extruder) can be minimized.

[0072] The polypropylene resin composition can be manufactured by melt-kneading a polypropylene resin, a heat-resistant agent, and a fiber reinforcement (i.e., glass fiber) at a temperature of 230° C. to 300° C. When the melt-kneading temperature is lower than 230° C., the melt-kneading temperature is higher than the melting point of the polypropylene resin, but the polypropylene resin cannot exhibit sufficient impregnation due to its low fluidity, and when the melt-kneading temperature is higher than 300° C., the quality of the polypropylene resin composition may be deteriorated due to thermal decomposition or volatilization of the additive or the polypropylene resin.

[0073] In addition, in order to improve the rigidity of the polypropylene resin composition, glass fiber as a fiber reinforcement is not fed into the same extruder but fed into an impregnation die while being continuously unwound from a separate stand, and an impregnation process is performed in which the fed polypropylene resin and heat-resistant agent fill the gaps between the filaments of the glass fiber bundle in the impregnation die.

[0074] The polypropylene resin composition according to the present invention may have: a tensile strength of 125 MPa or more according to ISO 527; a flexural strength of 170 MPa or more according to ISO 178; a thermal conductivity of 26 kJ / m according to ISO 180; 2 or higher impact strength; and according to ISO 75, 158° C. or higher heat deformation temperature under a load of 1.8 MPa.

[0075] In another aspect, the present invention relates to a molded product comprising the above-mentioned polypropylene resin composition.

[0076] The molded product can be applied to an ion filter, and the application field of the molded product is not limited.

[0077] The ion filter comprising the polypropylene resin composition according to the present invention is characterized in that it exhibits excellent chemical resistance and water resistance and low ion elution ability based on the stable performance of the polypropylene resin composition under a mild use environment, and achieves weight reduction.

[0078] The ion elution capacity of the molded product may be equal to or less than 0.8 ppm.

[0079] Hereinafter, the present invention will be described in more detail with reference to the following examples and comparative examples. The following examples and comparative examples are only used to exemplarily describe the present invention and are not intended to limit the scope and spirit of the present invention.

[0080] Examples 1-3 and Comparative Examples 2-17

[0081] To 100 parts by weight of polypropylene resin (HP480S, manufactured by PolyMirae Co., Ltd.), 4.92 parts by weight of a compatibilizer (NB1620, manufactured by Woosung Chemical Co., Ltd.), 3.28 parts by weight of an impact agent (Engage 8200, manufactured by The Dow Chemical Company), 0.55 parts by weight of a heat resistant agent (Songnox 1010, manufactured by SONGWON Industries Co., Ltd.), and respective amounts of corresponding surface modifiers (as listed in Table 1) were added and mixed using a twin-screw kneader (TEX-44) having a diameter of 44 mm. Respective amounts (as listed in Table 1) of glass fibers (SE4121, having a diameter of 15 to 20 μm and a length of 10 to 12 mm, manufactured by Owens Corning) supplied from roving as a fiber reinforcement were impregnated with the respective prepared mixtures, thereby preparing various polypropylene resin pellets having a length of 10 mm.

[0082] Comparative Example 1

[0083] Polypropylene resin pellets were produced in the same manner as in Example 1, except that the surface modifier was not added.

[0084] Comparative Example 18

[0085] Polypropylene resin pellets were manufactured in the same manner as in Example 1, except that a polyamide resin, i.e., polyamide 66 (PA66), and short (chopped) glass fibers having a diameter of 15 to 20 μm and a length of 2 to 5 mm were used as fiber reinforcements instead of the polypropylene resin and glass fibers (SE4121, having a diameter of 15 to 20 μm, produced by Owens Corning) used in Example 1.

[0086] Comparative Examples 19-21

[0087] Polypropylene resin pellets were produced in the same manner as in Example 1, except that short (chopped) glass fibers having a diameter of 15 to 20 μm and a length of 2 to 5 mm were used as a fiber reinforcement.

[0088] [Table 1]

[0089]

[0090]

[0091] [Table 2]

[0092]

[0093] Test Example 1: Comparison between Example and Comparative Example

[0094] The pellets manufactured according to Examples 1-3 and Comparative Examples 1-21 were made into samples using an injection molding machine with a clamping force of 170 tons to meet ISO standards and the fluidity of the resin, and the tensile strength, flexural strength, flexural modulus and impact strength of each sample were measured. The measurement results are listed in Table 3.

[0095] -Resin temperature setting: 260°C (260°C, 255°C, 250°C, 245°C, 245°C and 240°C)

[0096] -Mold temperature setting: 80℃

[0097] -Maintaining pressure: 50MPa

[0098] - Holding time: 5 seconds

[0099] -Cooling time: 15 seconds

[0100] -Tensile strength: measured by the method according to ISO 527

[0101] - Flexural strength: measured by the method according to ISO 178

[0102] -Flexural modulus: measured by the method according to ISO 178

[0103] - Impact strength: measured by a method according to ISO 180 - Heat deformation temperature: measured by a method according to ISO 75 - Specific gravity: measured by a method according to ISO 1183-1 [Table 3]

[0104]

[0105]

[0106] Referring to the above results, it can be confirmed that as the amount of the surface modifier increases (in Examples 1 to 3, compared with Comparative Example 1), the fluidity of the resin is improved, the filaments in the glass fiber bundle are easily impregnated with the resin, and thus the mechanical properties of the samples containing the polypropylene resin composition are improved.

[0107] In addition, it can be confirmed that when the surface modifier is not added, as in Comparative Example 1, the fluidity of the resin is low, the impregnation of the resin into the filaments in the glass fiber bundle is reduced, and thus the mechanical properties of the corresponding sample containing the polypropylene resin composition are not excellent. It can be confirmed that when the amount of the surface modifier is too low or too high, as in Comparative Example 4 or 5, the mechanical strength of the sample containing the polypropylene resin composition is significantly reduced.

[0108] It can be confirmed that in the case of Comparative Example 18 using conventional material, polyamide 66 (PA66), the specific gravity of the sample containing the polypropylene resin composition is somewhat large. Therefore, when a polypropylene resin is used instead of polyamide 66 (PA66) as in the present invention, a lightweight effect can be expected.

[0109] By comparing Examples 1-3 with Comparative Examples 1-5, it can be confirmed that when the amount of the fiber reinforcement is the same, the specific gravity of the samples including the corresponding polypropylene resin compositions is similar, but the tensile strength, bending strength and impact strength of the samples according to Examples 1-3 are higher than those of the samples according to Comparative Examples 1-5, and therefore, the polypropylene resin composition according to the present invention can be used to manufacture parts with stronger mechanical properties without increasing the weight of the parts.

[0110] In addition, the surface modifier is not limited to a specific kind, but it can be confirmed that the performance of the samples including the polypropylene resin composition using the silicon-based surface modifier according to Examples 1 to 3 is slightly better than the sample including the polypropylene resin composition using the wax-based surface modifier according to Comparative Example 2, and the sample including the polypropylene resin composition using the stearate-based surface modifier according to Comparative Example 3.

[0111] Test Example 2: Comparison of tensile strength at different coolant temperatures

[0112] The pellets produced according to Example 2 and Comparative Example 18 were made into respective samples using an injection molding machine with a clamping force of 170 tons, and the tensile strength of each sample at different coolant temperatures was measured. The measurement results are listed in Table 4 below.

[0113] [Table 4]

[0114]

[0115] Referring to the table, the mechanical properties of the sample according to Comparative Example 18 continuously decrease with aging in the coolant, but the mechanical properties of the sample according to Example 2 deteriorate very slightly even when the corresponding sample is exposed to the coolant.

[0116] The ion filter housing as the target component of the present application is characterized in that it is always exposed to the coolant. Through the above results, it can be confirmed that the sample according to Example 2 has a beneficial effect of being used as a vehicle component that can be used for a long time, compared with the conventional composition, that is, the sample according to Comparative Example 18, and thus can make up for the lack of mechanical properties in the initial stage.

[0117] That is, compared with the sample of Comparative Example 18 containing PA66 and not containing any surface modifier, the sample of Example 2 containing a polypropylene resin and a surface modifier has a high surface quality, and can minimize the pores between the fiber reinforcement and the resin exposed on the sample surface under a high-temperature antifreeze environment. In addition, the performance degradation of the surface layer of the glass fiber reinforced injection molded product caused by absorbing water from the pores can be prevented. That is, it can be confirmed that the addition of a surface modifier can show an effect of preventing the performance of a molded product containing a polypropylene resin composition from deteriorating under a high-temperature antifreeze environment.

[0118] In addition, polypropylene resin minimizes chemical reactions with coolants (50 wt% antifreeze + 50 wt% water) due to its molecular structure, so even when polypropylene resin is exposed to high-temperature coolants for a long time, the degradation of the mechanical properties of polypropylene resin is extremely limited. In contrast, due to the characteristics of amide materials, PA66 hydrolyzes in high-temperature coolants, resulting in continuous degradation of the mechanical properties of PA66. Therefore, it can be confirmed that polypropylene resin is advantageous in a high-temperature coolant environment compared to PA66.

[0119] Test Example 3: Comparison of ion elution ability

[0120] Molded products (ion filters) comprising the compositions according to Example 2 and Comparative Example 18 were manufactured, and the ion elution capabilities of the molded products were measured. The measurement results are shown in Table 5 below.

[0121] -Measurement method: Measured using MS211-80 (ion elution evaluation method) and ICP-AES (inductively coupled plasma atomic emission spectrometry)

[0122] [Table 5]

[0123] It can be confirmed that the molded product according to Example 2 has a low processing temperature compared to the molded product using PA66 according to Comparative Example 18, and has improved ion elution ability compared to the molded product containing the conventional composition. This is because the change from the internal combustion engine vehicle environment to the fuel cell electric vehicle environment causes the ambient temperature to decrease and the requirements for heat resistance are reduced, so antioxidants and heat stabilizers including metal ions can be omitted.

[0124] As is apparent from the above description, the polypropylene resin composition according to the present invention can prevent performance degradation due to moisture and can have low surface energy, thereby being able to increase chemical stability to external factors. In addition, a molded product comprising the polypropylene resin composition can have low ion elution ability (which is the most important requirement) and can achieve a high degree of lightweight.

[0125] The invention has been described in detail with reference to preferred embodiments. However, those skilled in the art will appreciate that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A polypropylene resin composition, comprising: Polypropylene resin; Fiber reinforcements; and Surface modifiers.

2. The polypropylene resin composition according to claim 1, wherein Based on 100 parts by weight of the polypropylene resin, the amount of the fiber reinforcement is 40 parts by weight to 55 parts by weight.

3. The polypropylene resin composition according to claim 1, wherein The amount of the surface modifier is 0.1 to 1 parts by weight based on 100 parts by weight of the polypropylene resin.

4. The polypropylene resin composition according to claim 1, wherein The number average molecular weight Mn of the polypropylene resin is 15,000 g / mol to 30,000 g / mol.

5. The polypropylene resin composition according to claim 1, wherein The polypropylene resin includes at least one selected from a polypropylene homopolymer and an ethylene-propylene copolymer.

6. The polypropylene resin composition according to claim 1, wherein The polypropylene resin has a melt index MI of 30 to 50 g / 10 min, measured at a temperature of 230° C. and a load of 2.16 kg.

7. The polypropylene resin composition according to claim 1, wherein The fiber reinforcement includes at least one selected from glass fiber, carbon fiber, graphite fiber, metal fiber, basalt fiber, cotton fiber, wool fiber, silk fiber, aramid fiber, polyacrylonitrile fiber, arylate fiber, polyetheretherketone fiber, nylon fiber and polyethylene terephthalate fiber.

8. The polypropylene resin composition according to claim 1, wherein The length of the fiber reinforcement is 6 mm to 25 mm.

9. The polypropylene resin composition according to claim 1, wherein The fiber reinforcement has a diameter of 12 μm to 20 μm.

10. The polypropylene resin composition according to claim 1, wherein The surface modifier includes at least one selected from silicon-based surface modifiers, wax-based surface modifiers and stearate-based surface modifiers. 11 . The polypropylene resin composition according to claim 1 , further comprising an additive, wherein the additive comprises at least one selected from the group consisting of a compatibilizer, an impact resistant agent, and a heat resistant agent. 12 . The polypropylene resin composition according to claim 11 , comprising the compatibilizer, wherein the compatibilizer comprises at least one selected from the group consisting of a polypropylene homopolymer, an ethylene-propylene copolymer, and an ethylene-octene copolymer.

13. The polypropylene resin composition according to claim 11, comprising the compatibilizer, wherein the compatibilizer is grafted with 0.8 wt% to 1.2 wt% of maleic anhydride based on the total weight of the compatibilizer.

14. The polypropylene resin composition according to claim 11, comprising the compatibilizer, wherein: Based on 100 parts by weight of the polypropylene resin, the amount of the compatibilizer is 1 part by weight to 10 parts by weight.

15. The polypropylene resin composition according to claim 11, comprising the impact-resistant agent, wherein: The amount of the impact resistant agent is 1 to 5 parts by weight based on 100 parts by weight of the polypropylene resin.

16. The polypropylene resin composition according to claim 11, comprising the heat-resistant agent, wherein: The heat-resistant agent includes at least one selected from phenolic heat-resistant agents and phosphate heat-resistant agents.

17. The polypropylene resin composition according to claim 11, comprising the heat-resistant agent, wherein: The amount of the heat-resistant agent is 0.1 to 1 parts by weight based on 100 parts by weight of the polypropylene resin.

18. The polypropylene resin composition according to claim 1, wherein The polypropylene resin composition has: Tensile strength of 125 MPa or higher according to ISO 527; Flexural strength of 170 MPa or higher according to ISO 178; According to ISO 180, 26 kJ / m 2 or higher impact strength; and According to ISO 75, a heat distortion temperature of 158°C or higher under a load of 1.8 MPa.

19. A molded product comprising the polypropylene resin composition according to claim 1.

20. The molded product of claim 19, further comprising an ion filter.

21. The molded product of claim 19, wherein The molded product has an ion elution capability of 0.8 ppm or less.

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