Thermoplastic elastomer composition and thermoplastic elastomer manufactured by using the same

Abstract

A thermoplastic elastomer composition is provided, comprising 80 parts by weight of ethylene propylene diene monomer (EPDM) containing 5-ethylidene-2-norbornene (ENB) and polyethylene, 30 to 70 parts by weight of polypropylene, 20 to 40 parts by weight of a filler, and 60 to 90 parts by weight of a plasticizer.

Description

Technology Field

[0001] The present invention relates to a composition of an EPDM / PP thermoplastic elastomer that simultaneously improves material damping characteristics and permanent compression set, and a thermoplastic elastomer produced thereby. Background Technology

[0002] Weatherstrips are positioned around the vehicle body or door area to ensure that the door glass operates along a precise trajectory when raised or lowered, or to prevent it from deviating. Additionally, they serve as a sealing mechanism for the vehicle body to prevent external contaminants, such as snow and rain, from entering between the glass and the door.

[0003] In particular, the inner belt weatherstrip serves to seal the vehicle interior and door glass to block the ingress of foreign matter and wind noise. The inner belt weatherstrip requires not only sealing performance but also excellent vibration and soundproofing performance. That is, there is a problem of vibration and noise caused by friction between the door glass and the inner belt strip when the glass is raised or lowered.

[0004] Meanwhile, EPDM / PP thermoplastic elastomers are manufactured through a blend of thermosetting elastomer (EPDM) and thermoplastic plastic (PP), and are produced through dynamic crosslinking in which the crosslinking of EPDM proceeds during the blending process.

[0005] These EPDM / PP thermoplastic elastomers are being used in the automotive industry as eco-friendly, lightweight materials due to the introduction of thermoplastic plastics, which allows them to be remolded and recycled unlike conventional thermosetting elastomers, as well as the advantage of lower density compared to EPDM.

[0006] However, due to the low damping characteristics of the material, when applied to inner belt weatherstrips, there is a problem of noise and vibration caused by friction at low temperatures (-4°C to 4°C). In addition, increasing the damping of the material increases the permanent compression set, which adversely affects the sealing performance of the inner belt weatherstrip. The problem to be solved

[0007] One embodiment provides a thermoplastic elastomer composition that can contribute to improving sensory quality by simultaneously improving material damping performance and permanent compression set, thereby improving sealing performance when applied to an inner belt weatherstrip and reducing friction noise and vibration. means of solving the problem

[0008] According to one embodiment, a thermoplastic elastomer composition is provided comprising 80 parts by weight of ethylene propylene diene monomer (EPDM) containing 5-ethylidene-2-norbornene (ENB) and polyethylene, 30 to 70 parts by weight of polypropylene, 20 to 40 parts by weight of a filler, and 60 to 90 parts by weight of a plasticizer.

[0009] The ethylene propylene diene monomer may contain 5% to 10% by weight of 5-ethylidene-2-norbornene and 50% to 70% by weight of polyethylene based on the total weight of the ethylene propylene diene monomer.

[0010] The ethylene propylene diene monomer may contain 8.9% to 10% by weight of 5-ethylidene-2-norbornene and 50% to 58% by weight of polyethylene with respect to the total weight of the ethylene propylene diene monomer.

[0011] The ethylene propylene diene monomer has a degree of crystallinity of 0% to 15.8% and a crosslinking density of 2.26 x 10⁻⁶ -4 mol / ml to 2.68 x 10⁻⁶ -4 It is mol / ml, and the molecular weight distribution can be 3.4 to 4.3.

[0012] The thermoplastic elastomer composition may contain 30 to 35 parts by weight of polypropylene.

[0013] Polypropylene may have a degree of crystallinity of 52% to 60%.

[0014] The thermoplastic elastomer composition may contain 85 to 90 parts by weight of a plasticizer.

[0015] The thermoplastic elastomer composition may further include 0.1 to 1.25 parts by weight of a crosslinking agent.

[0016] The thermoplastic elastomer composition may further comprise 0.1 to 0.5 parts by weight of a crosslinking agent, 0.1 to 0.5 parts by weight of an antioxidant, 1 to 3 parts by weight of a surface modifier, 1 to 3 parts by weight of a lubricant, 1 to 3 parts by weight of a crosslinking accelerator, 1 to 5 parts by weight of a UV stabilizer, or a mixture thereof.

[0017] According to another embodiment, a thermoplastic elastomer is provided, which is manufactured from a thermoplastic elastomer composition according to one embodiment, has a loss factor (Tan δ) of 0.139 or higher and a permanent compression set of 45.44% or lower.

[0018] The thermoplastic elastomer may have a loss factor (Tan δ) of 0.144 to 0.158 and a permanent compression set of 29.53% to 35.35%.

[0019] The thermoplastic elastomer may have a static friction coefficient of 0.9 or less, a kinetic friction coefficient of 0.69 or less, and a maximum acceleration of 2.44 g or less during stick-slip.

[0020] According to another embodiment, a method for manufacturing a thermoplastic elastomer according to another embodiment is provided, comprising: a powder mixing step of mixing a powder containing a filler; an extruder feeding step of feeding ethylene propylene diene monomer (EPDM), polypropylene (PP), and the mixed powder into an extruder; a mixing step of mixing the ethylene propylene diene monomer and polypropylene in the extruder; and an EPDM dynamic crosslinking step of dynamically crosslinking the ethylene propylene diene monomer.

[0021] According to another embodiment, a weatherstrip for an automobile comprising a thermoplastic elastomer according to another embodiment is provided. Effects of the invention

[0022] A thermoplastic elastomer composition according to one embodiment can improve material damping performance and permanent compression set simultaneously, and when applied to an inner belt weatherstrip, it can improve sealing performance and reduce friction noise and vibration, thereby contributing to the improvement of sensory quality. Brief explanation of the drawing

[0023] FIG. 1 is a process flowchart showing the manufacturing process of a thermoplastic elastomer according to one embodiment. FIG. 2 is a cross-sectional view illustrating a weatherstrip for an automobile according to one embodiment. Figure 3 is a graph showing the results of measuring the crystallinity, crosslinking density, and molecular weight distribution of EPDM in Experimental Example 2, and the material damping characteristics of the thermoplastic elastomer according to the change in the crystallinity of PP. Figure 4 is a graph showing the results of measuring the degree of crystallization, crosslinking density, and molecular weight distribution of EPDM in Experimental Example 2, and the permanent compression set of the thermoplastic elastomer according to the change in the degree of crystallization of PP. Figures 5 to 7 are electron microscope images showing the particle size of EPDM according to the ENB content of EPDM. Figure 8 is a graph showing the results of measuring the material damping characteristics of a thermoplastic elastomer according to changes in the content of the crosslinking agent, plasticizer, and filler in Experimental Example 3. Figure 9 is a graph showing the results of measuring the permanent compression set of a thermoplastic elastomer according to changes in the content of the crosslinking agent, plasticizer, and filler in Experimental Example 3. Figure 10 is a graph showing the results of measuring the change in the coefficient of friction of thermoplastic elastomers according to Manufacturing Examples 1 to 5 in Experimental Example 4. Figure 10 is a graph showing the results of measuring the change in the magnitude of the frictional vibration acceleration of thermoplastic elastomers according to Manufacturing Examples 1 to 5 in Experimental Example 4. Specific details for implementing the invention

[0024] The advantages and features of the technology described below, and the methods for achieving them, will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the forms of implementation are not limited to the embodiments disclosed below. Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning that is commonly understood by those skilled in the art. Furthermore, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0025] When a part of a specification is described as "including" a certain component, unless specifically stated otherwise, this means that it does not exclude other components but may include additional components.

[0026] In addition, the singular form includes the plural form unless specifically mentioned otherwise in the phrase.

[0027] A thermoplastic elastomer composition according to one embodiment comprises 80 parts by weight of ethylene propylene diene monomer (EPDM), 30 to 70 parts by weight of polypropylene, 20 to 40 parts by weight of filler, and 60 to 90 parts by weight of plasticizer.

[0028] The thermoplastic elastomer composition includes a mixture of ethylene propylene diene monomer and polypropylene as a matrix resin.

[0029] Ethylene propylene diene monomer improves the excellent extrusion moldability and recovery rate of the door side extrusion molded part, and strengthens weather resistance and heat resistance.

[0030] Ethylene propylene diene monomer may be included in an amount of 80 parts by weight. If the content of ethylene propylene diene monomer is too low, poor product flowability may occur during extrusion molding, resulting in reduced dimensional stability and difficulty in molding, and the recovery rate of the product may decrease. If the amount is too high, the hardness of the finished product increases, which lowers the compressive load and permanent compression set characteristics that significantly affect door side performance, and may cause difficulties in working when mounting the final product on the door.

[0031] Ethylene propylene diene monomer may include 5-ethylidene-2-norbornene (ENB) and polyethylene.

[0032] The ethylene propylene diene monomer may contain 50% to 70% by weight of polyethylene based on the total weight of the ethylene propylene diene monomer, and may contain, for example, 76% or less by weight, 62% or less by weight, 58% or less by weight, or 56% or less by weight. As the content of polyethylene in the ethylene propylene diene monomer decreases, the loss factor (Tan δ), which is the material damping characteristic of the thermoplastic elastomer, increases, and the permanent compression set may decrease.

[0033] If the polyethylene content is less than 50% by weight relative to the total weight of the ethylene propylene diene monomer, the tensile strength may decrease, leading to a decrease in physical properties, and if it exceeds 70% by weight, the degree of crystallinity may increase, leading to a decrease in permanent compression set.

[0034] The ethylene propylene diene monomer may contain 5-ethylidene-2-norbornene in an amount of 5% to 10% by weight relative to the total weight of the ethylene propylene diene monomer, and may contain, for example, 5.7% or more by weight, 7.3% or more by weight, or 8.9% or more by weight. As the content of 5-ethylidene-2-norbornene in the ethylene propylene diene monomer increases, the loss factor (Tan δ), which is the material damping characteristic of the thermoplastic elastomer, increases, and the permanent compression set may decrease.

[0035] If the content of 5-ethylidene-2-norbornene is less than 5 weight% relative to the total weight of the ethylene propylene diene monomer, extrusion and injection molding may be difficult, and if it exceeds 10 weight%, the hardness and strength of the product increase, making it difficult to cut during extrusion and injection molding.

[0036] As the polyethylene content of the ethylene propylene diene monomer increases, the degree of crystallization of the ethylene propylene diene monomer increases, and as the content of 5-ethylidene-2-norbornene increases, the crosslinking density of the ethylene propylene diene monomer increases. Therefore, the ethylene propylene diene monomer has a degree of crystallization of 0% to 15.8% and a crosslinking density of 2.26 x 10⁻⁶. -4 mol / ml to 2.68 x 10⁻⁶ -4 It may be mol / ml and have a molecular weight distribution of 3.4 to 4.3. The degree of crystallinity increases with increasing PE content in the ethylene propylene diene monomer, and the molecular weight distribution may differ depending on the polymerization catalyst (Ziegler-Natta - broad distribution, metallocene - narrow distribution) used during the production of the ethylene propylene diene monomer. Accordingly, as the degree of crystallinity of the ethylene propylene diene monomer decreases, the crosslinking density increases, and the molecular weight distribution increases, the loss factor (Tan δ), which is the material damping characteristic of the thermoplastic elastomer, increases, and the permanent compression set may decrease.

[0037] Polypropylene (PP) serves to form the matrix of the ethylene propylene diene monomer and enhances oil and durability properties. Polypropylene may be included in an amount of 30 to 70 parts by weight per 80 parts by weight of the ethylene propylene diene monomer, for example, in an amount of 30 to 35 parts by weight. If the polypropylene content is less than 30 parts by weight, extrusion molding may be difficult due to low flowability, and if it exceeds 70 parts by weight, performance may be degraded due to increased hardness of the finished product, and work may be difficult when mounting the door side extrusion molding part.

[0038] Polypropylene may be homopolypropylene with a degree of crystallinity of 52% to 60%. Homopolypropylene has a higher degree of crystallinity compared to random copolymers with polyethylene or block copolymers with polyethylene. As the degree of crystallinity of polypropylene decreases, the loss factor (Tan δ), which is a material damping characteristic of the thermoplastic elastomer, increases, and the permanent compression set may decrease.

[0039] The plasticizer may be, for example, high-viscosity paraffin oil, and the high-viscosity paraffin oil may have a kinematic viscosity of 170 or higher at 40°C.

[0040] Plasticizers promote processability during the manufacture of thermoplastic elastomer compositions and facilitate the dispersion of fillers. Additionally, they reduce the hardness of the thermoplastic elastomer composition, thereby increasing plasticity and moldability.

[0041] The plasticizer may be included in an amount of 60 to 90 parts by weight per 80 parts by weight of ethylene propylene diene monomer, and may be included in an amount of, for example, 65 parts by weight or more, 75 parts by weight or more, or 85 parts by weight or more. As the content of the plasticizer increases, the loss factor (Tan δ), which is the material damping characteristic of the thermoplastic elastomer, increases, and the permanent compression set may decrease.

[0042] If the plasticizer content is less than 60 parts by weight, the flowability during extrusion molding may be poor, which may cause molding defects and work defects, and if it exceeds 90 parts by weight, the flowability may increase, resulting in a poor extrusion shape and requiring a long cooling time.

[0043] The thermoplastic elastomer composition may further include a crosslinking agent. As an example, the crosslinking agent may include a phenolic resin crosslinking agent, a peroxide crosslinking agent, a silane crosslinking agent, or a combination thereof.

[0044] Crosslinking agents play a role in crosslinking the rubber portion to enable the physical properties of thermoplastic elastomers. Thermoplastic elastomers are manufactured to possess rubber-like viscosity and elasticity by adding a crosslinking agent to crosslink the rubber portion, which is the soft segment, and performing dynamic crosslinking using a twin-screw extruder. At this time, phenolic resin crosslinking agents are chemical substances that are highly sensitive to moisture and can cause problems due to moisture absorption during the summer, whereas peroxide crosslinking agents have fewer problems related to moisture absorption compared to phenolic resin.

[0045] For example, the peroxide crosslinking agent may have the structure of 2,5-dimethyl-2,5-di-(tert-butylperoxy)-hexane, a half-life temperature of 170°C, and a molecular weight of 290 or more.

[0046] The crosslinking agent may be included in an amount of 0.1 to 1.25 parts by weight per 80 parts by weight of ethylene propylene diene monomer, for example, 1.0 part by weight or less, or 0.76 parts by weight or less. As the content of the crosslinking agent decreases, the loss factor (Tan δ), which is the material damping characteristic of the thermoplastic elastomer, may increase.

[0047] If the content of the crosslinking agent is less than 0.1 parts by weight, crosslinking may not occur sufficiently, which may result in a decrease in the physical properties and elasticity of the finished product. If it exceeds 1.25 parts by weight, excessive crosslinking may occur, which may result in the observation of foreign substances such as fish-eyes on the surface and cause defects in the appearance and moldability of the extrusion molding machine.

[0048] The filler may be an inorganic filler, for example, calcium carbonate with a particle size of 10 μm or less and a whiteness of 95% or more may be used as the inorganic filler.

[0049] The filler may be included in an amount of 20 to 40 parts by weight per 80 parts by weight of ethylene propylene diene monomer. If the filler content is less than 20 parts by weight, the cost of other materials increases and its role as a filler may be negligible, and if it exceeds 40 parts by weight, the hardness increases and the flowability of the material decreases, making extrusion molding difficult.

[0050] The thermoplastic elastomer composition may further include other additives such as a crosslinking agent, an antioxidant, a surface modifier, a lubricant, a crosslinking accelerator, a UV stabilizer, or a mixture thereof. As an example, the thermoplastic elastomer composition may further include, with respect to 80 parts by weight of ethylene propylene diene monomer, 0.1 to 0.5 parts by weight of a crosslinking agent, 0.1 to 0.5 parts by weight of an antioxidant, 1 to 3 parts by weight of a surface modifier, 1 to 3 parts by weight of a lubricant, 1 to 3 parts by weight of a crosslinking accelerator, 20 to 40 parts by weight of a filler, 1 to 5 parts by weight of a UV stabilizer, or a mixture thereof.

[0051] For example, the crosslinking agent may be N,N'-m-phenylenedimaleimide, 1,2-polybutadiene, or a mixture thereof.

[0052] If the content of the crosslinking agent is less than 0.1 parts by weight, the effect of use may be negligible, and if it exceeds 0.5 parts by weight, fish eyes may occur on the product surface due to over-crosslinking, which may degrade the appearance quality of the product.

[0053] The antioxidant has a melting point of 120°C or higher and a whiteness of 95% or higher, and may be, for example, tetrakis(3,5-di-tertbutyl-4-hydroxyphenyl)propionate, tetrakis-(3-dodecylthiopropionate), or a mixture thereof.

[0054] If the content of the antioxidant is less than 0.1 parts by weight, the physical properties of the thermoplastic elastomer composition may deteriorate and the performance of the finished product may deteriorate when used for a long period of time, and if it exceeds 0.5 parts by weight, blooming may occur in the product.

[0055] The surface modifier may be, for example, a polypropylene-based wax. The polypropylene-based wax may have a specific gravity of 0.90 or less and a melting point of 160 °C or higher.

[0056] If the content of the surface modifier is less than 1 part by weight, the effect of improving the scratch resistance of the finished product is negligible, and the wear resistance may be reduced, and if it exceeds 3 parts by weight, the surface modifier may migrate to the surface of the finished product, making it difficult to achieve product characteristics.

[0057] The UV stabilizer may be, for example, a benzotriazole type UV absorber, an oligomeric Hindered Amine Light Stabilizer type UV stabilizer, or a mixture thereof.

[0058] If the content of the UV stabilizer is less than 1 part by weight, surface whitening and microcracks may occur due to UV attack, and if it exceeds 5 parts by weight, the UV stabilizer with a low molecular weight may migrate to the surface and cause blooming on the product's appearance.

[0059] According to another embodiment, a thermoplastic elastomer is manufactured using a thermoplastic elastomer composition.

[0060] As described above, as the content of polyethylene in the ethylene propylene diene monomer of the thermoplastic elastomer composition decreases and the content of 5-ethylidene-2-norbornene in the ethylene propylene diene monomer increases, the degree of crystallinity of the ethylene propylene diene monomer decreases, the crosslinking density increases, and the molecular weight distribution increases, the loss factor (Tan δ), which is the material damping characteristic of the thermoplastic elastomer, increases, and the permanent compression set can decrease.

[0061] In addition, as the degree of crystallinity of polypropylene in the thermoplastic elastomer composition decreases, the content of the plasticizer increases and the content of the crosslinking agent decreases, the loss factor (Tan δ), which is the material damping characteristic of the thermoplastic elastomer, increases and the permanent compression set may decrease.

[0062] Accordingly, the thermoplastic elastomer manufactured using the thermoplastic elastomer composition simultaneously improves the material damping performance and permanent compression set, which are in a trade-off relationship with each other.

[0063] For example, the thermoplastic elastomer may have a loss factor (Tan δ) indicating material damping performance of 0.139 or higher when measured at room temperature (24 ℃), and may be, for example, 0.140 or higher, 0.141 or higher, 0.142 or higher, 0.143 or higher, 0.144 or higher, 0.145 or higher, 0.148 or higher, 0.149 or higher, 0.150 or higher, 0.152 or higher, 0.153 or higher, 0.155 or higher, or 0.158 or higher, and may be 0.144 to 0.158.

[0064] In addition, the thermoplastic elastomer may have a loss factor (Tan δ) indicating material damping performance of 0.110 or higher when measured at low temperature (-4 ℃ to 4 ℃), and may, for example, be 0.114 or higher, 0.115 or higher, 0.116 or higher, 0.117 or higher, 0.118 or higher, 0.121 or higher, 0.122 or higher, 0.123 or higher, or 0.124 or higher.

[0065] The loss factor (Tan δ) representing the damping performance of the material can be obtained by using TA Instrument's Q850 instrument (dynamic mechanical analysis, DMA) to perform a temperature sweep at 0.2% dynamic strain and 10 Hz, and then calculating the average value of tanδ at room temperature (24 ℃) or low temperature (-4 ℃ to 4 ℃).

[0066] The thermoplastic elastomer may have a permanent compression set of 45.44% or less, for example, 43.75% or less, 43.26% or less, 43.13% or less, 42.97% or less, 40.49% or less, 35.35% or less, 34.59% or less, 31.45% or less, 30.94% or less, 30.70% or less, 30.44% or less, 30.37% or less, 30.29% or less, 30.17% or less, 30.04% or less, 29.51% or less, 28.17% or less, 29.53% or less, 29.51% or less, or 27.55% or less, and may be between 29.53% and 35.35%.

[0067] Permanent compression set can be measured by applying a strain of 25% according to ISO815 and running it in an oven at 70°C for 22 hours.

[0068] In addition, the thermoplastic elastomer may have a static friction coefficient of 0.9 or less, for example, 0.83 or less, or 0.69 or less, a kinetic friction coefficient of 0.69 or less, for example, 0.67 or less, or 0.64 or less, and a maximum acceleration during stick-slip representing noise acceleration may be 2.44 g or less, for example, 1.38 g or less, or 1.03 g or less (where g is the unit of gravitational acceleration, 1 g = 9.81 m / s²). 2 am).

[0069] The coefficient of friction and the maximum acceleration during stick-slip can be measured by conducting a friction test using equipment from Zins-Ziegler under conditions of a vertical load of 5 N and a speed of 3 mm / s.

[0070] In this way, as the thermoplastic elastomer improves both material damping performance and permanent compression set, when applied to inner belt weatherstrips, it can contribute to improving sensory quality by improving sealing performance and reducing friction noise and vibration.

[0071] FIG. 1 is a process flowchart showing the process of manufacturing a thermoplastic elastomer according to another embodiment.

[0072] Referring to FIG. 1, a method for manufacturing a thermoplastic elastomer includes a powder mixing step (S1), an extruder feeding step (S2), a mixing step of ethylene propylene diene monomer (EPDM) and polypropylene (PP) (S3), and an EPDM dynamic crosslinking step (S4).

[0073] In the powder mixing step (S1), powders such as fillers and other additives are premixed in addition to ethylene propylene diene monomer (EPDM) and polypropylene (PP). Specifically, various chemicals are mixed and dispersed within a supermixer to prepare for the introduction of the dispersed chemicals.

[0074] In the extruder feeding step (S2), each raw material is fed into the extruder. Specifically, ethylene propylene diene monomer (EPDM), polypropylene (PP), and pre-mixed powder are fed into the extruder in a fixed ratio through a metering device.

[0075] In the EPDM and PP mixing step (S3), each raw material is mixed through the gap between the screw and the barrel of the extruder.

[0076] In the EPDM dynamic crosslinking step (S4), EPDM is dynamically crosslinked. The temperature of the barrel is controlled, and an optimized dynamic crosslinking reaction is carried out through a screw assembly. To increase the efficiency of the dynamic crosslinking reaction, a kneading section (shear force reinforcement) is added to the screw assembly to further reduce the EPDM particle size.

[0077] Finally, the dynamically cross-linked thermoplastic elastomer product can be pelletized by cutting it simultaneously with extrusion (S5).

[0078] A weatherstrip for an automobile according to another embodiment includes a thermoplastic elastomer according to another embodiment.

[0079] FIG. 2 is a cross-sectional view illustrating a weatherstrip for an automobile. Referring to FIG. 2, the weatherstrip (10) may include a sealing lip (11) and a flocking member (12) forming a contact surface with the door glass (2), a body part (13) including a reinforcing core made of SUS material inserted inside and acting as a support, a fixing part (15) fixed outwardly along the beltline part of the door panel (1), and an outer wall sealing lip (16) that is closely supported on the door panel (1).

[0080] At this time, the sealing rib (11), the fixing part (15), the outer wall sealing rib (16), or a combination thereof may include a thermoplastic elastomer.

[0081] Specific embodiments of the invention are presented below. However, the embodiments described below are merely for the purpose of specifically illustrating or explaining the invention and should not limit the scope of the invention.

[0082] [Manufacturing Example: Preparation of a Thermoplastic Elastomer]

[0083] (Preparation Example 1)

[0084] After mixing in the ratios shown in Table 1, an EPDM / PP thermoplastic elastomer was manufactured using a twin-screw extruder.

[0085] (Preparation Example 2)

[0086] It was prepared in the same manner as in Preparation Example 1, except that polypropylene (PP) was mixed in at a weight of 31 parts as shown in Table 1.

[0087] (Preparation Example 3)

[0088] It was prepared in the same manner as in Preparation Example 2, except that EPDM with a polyethylene (PE) content of 56 wt% was mixed.

[0089] (Preparation Example 4)

[0090] It was prepared in the same manner as in Preparation Example 3, except that EPDM with a 5-ethylidene-2-norbornene (ENB) content of 8.9 wt% was mixed.

[0091] (Preparation Example 5)

[0092] It was prepared in the same manner as in Preparation Example 4, except that 75 parts by weight of plasticizer (process oil) were mixed.

[0093] ingredient Preparation Example 1 Preparation Example 2 Preparation Example 3 Preparation Example 4 Preparation Example 5 EPDM 80 80 80 80 80 PE content 67 wt% 67 wt% 56 wt% 58 wt% 58 wt% ENB content 5.7 wt% 5.7 wt% 5.7 wt% 8.9 wt% 8.9 wt% PP 71 31 31 31 31 crosslinking agent 1) 0.76 0.76 0.76 0.76 0.76 Bridge 2) 0.27 0.27 0.27 0.27 0.27 Surface modifier 2 2 2 2 2 lubricant 3) 1.7 1.7 1.7 1.7 1.7 antioxidants 0.4 0.4 0.4 0.4 0.4 Crosslinking accelerator 4) 3 3 3 3 3 Filler 5) 29.5 29.5 29.5 29.5 29.5 UV stabilizer 2 2 2 2 2 plasticizer 6) 75 75 75 75 85

[0094] (Unit: parts by weight)

[0095] 1) Crosslinking agent: Peroxide

[0096] 2) Crosslinking agent: Triallyl cyanurate

[0097] 3) Lubricant: Stearic acid

[0098] 4) Crosslinking accelerator: Zinc oxide

[0099] 5) Filler: Calcium carbonate, carbon black

[0100] 6) Plasticizer: Paraffin oil

[0101] [Experimental Example 1]

[0102] The thermoplastic elastomer compositions prepared through Preparation Examples 1 to 5 were manufactured into 2 mm thick sheets using an injection molding machine and then processed into various specimens for physical property evaluation.

[0103] The physical property tests conducted are as follows, and the results are shown in Tables 2 and 3.

[0104] 1) Tensile properties: Measured at a speed of 500 mm / min using Daekyung Engineering's DUT-500C equipment in accordance with ISO37 standards.

[0105] 2) Permanent compression set: After applying a strain of 25% in accordance with ISO815 standards, the process was carried out in an oven at 70°C for 22 hours.

[0106] 3) Material damping (tanδ): Measurements were taken using a TA instrument Q850 instrument (dynamic mechanical analysis, DMA) after performing a temperature sweep at 0.2% dynamic strain and 10 Hz, and the average tanδ value at room temperature (24 ℃) or low temperature (-4 ℃ to 4 ℃) was derived.

[0107] 4) Friction coefficient and noise acceleration: Friction tests were conducted using equipment from Zins-Ziegler under conditions of a vertical load of 5 N and a velocity of 3 mm / s to measure the friction coefficient and the acceleration peak during stick-slip.

[0108] Physical properties unit Preparation Example 1 Preparation Example 2 Preparation Example 3 Preparation Example 4 Preparation Example 5 50% Modulus Mpa 2.94 1.47 1.24 1.28 1.07 tensile strength Mpa 7.14 4.39 4.05 4.63 4.18 Tensile elongation - 5.04 3.19 3.43 3.5 3.43 Permanent compression set 70℃ x 22hr % 45.44 35.35 31.45 29.51 29.53 Material Damping (Tan δ) -4~4℃, 10Hz - 0.139 0.144 0.149 0.155 0.158

[0109] Physical properties unit Preparation Example 1 Preparation Example 2 Preparation Example 3 coefficient of static friction - 0.9 0.83 0.69 coefficient of kinetic friction - 0.67 0.69 0.64 Maximum acceleration g 2.44 1.38 1.03

[0110] Referring to Table 2, when comparing Preparation Example 1 and Preparation Example 2, when the PP content was reduced from 51 parts by weight to 31 parts by weight, the 50% modulus, tensile strength, and tensile elongation decreased by 50.0%, 38.5%, and 36.7%, respectively, but the permanent compression set was improved by 22.2% and the material damping was also improved by 3.6%.

[0111] When comparing Preparation Example 2 and Preparation Example 3, when the PE content of EPDM was reduced from 67 wt% to 56 wt%, the 50% modulus and tensile strength decreased by 15.6% and 7.7%, respectively, but the tensile elongation increased by 7.5%. In addition, the permanent compression set and material damping were improved by 11.0% and 3.5%, respectively.

[0112] When comparing Preparation Example 3 and Preparation Example 4, increasing the ENB content of EPDM from 5.7 wt% to 8.9 wt% resulted in a 50% modulus, tensile strength, and tensile elongation increase of 3.2%, 14.3%, and 2.0%, respectively. Additionally, permanent compression set and material damping were improved by 6.2% and 4.0%, respectively.

[0113] When comparing Preparation Example 4 and Preparation Example 5, increasing the content of the plasticizer (Process oil) from 75 parts by weight to 85 parts by weight resulted in a decrease of 16.4%, 9.7%, and 2.0% in 50% modulus, tensile strength, and tensile elongation, respectively. The permanent compression set showed almost similar values, and the material damping improved by 1.9%, confirming that Preparation Example 5 exhibited the highest material damping at 0.158 and had a low permanent compression set of 29.53%.

[0114] Referring to Table 3, when comparing Preparation Examples 1 to 3, as the material damping increased, the static friction coefficient decreased by 7.8% and 16.9% to 0.90, 0.83, and 0.69, respectively, while the kinetic friction coefficient increased by 3.0% and decreased by 7.2% to 0.67, 0.69, and 0.64, respectively, confirming that Preparation Example 5 had the lowest friction coefficient. The maximum acceleration when stick-slip occurred decreased by 43.4% and 25.4% to 2.44, 1.38, and 1.03, respectively, confirming that Preparation Example 5 had a noise and vibration reduction effect.

[0115] [Experimental Example 2]

[0116] In a thermoplastic elastomer comprising 35.4 wt% EPDM and 13.7 wt% PP, the material damping characteristics and permanent compression set of the thermoplastic elastomer were measured according to changes in the crystallinity, crosslinking density, and molecular weight distribution of EPDM and the crystallinity of PP, and the results are shown in FIGS. 3 and 4. The material damping characteristics and permanent compression set were measured in the same manner as in Experimental Example 1.

[0117] In FIGS. 3 and 4, TPV 60, TPV 70, and TPV 80 are cases where the PP content is 31 parts by weight (14 wt%), 51 parts by weight (21 wt%), and 71 parts by weight (27 wt%), respectively, and the specific composition is as shown in Table 4; Low EPDM Crystallinity, Mid EPDM Crystallinity, and High EPDM Crystallinity are cases where the PE content of EPDM is 56 wt%, 62 wt%, and 67 wt%, respectively, and Low EPDM Crosslink density, Mid EPDM Crosslink density, and High EPDM Crosslink density are cases where the ENB content of EPDM is 5.7 wt%, 7.3 wt%, and 8.9 wt%, respectively.

[0118] ingredient TPV60 TPV70 TPV80 EPDM 80 (35 wt%) 80 (33 wt%) 80 (30 wt%) PP 31 (14 wt%) 51 (21 wt%) 71 (27 wt%) crosslinking agent 1) 0.76 0.76 0.76 Bridge 2) 0.27 0.27 0.27 lubricant 3) 1.7 1.7 1.7 Crosslinking accelerator 4) 3 3 3 First filler 5) 13.5 13.5 13.5 Second filler 6) 6 6 6 plasticizer 7) 75 75 75

[0119] (Unit: parts by weight)

[0120] 1) Crosslinking agent: Peroxide

[0121] 2) Crosslinking agent: Triallyl cyanurate

[0122] 3) Lubricant: Stearic acid

[0123] 4) Crosslinking accelerator: Zinc oxide

[0124] 5) First filler: Calcium carbonate

[0125] 6) Second filler: Carbon black

[0126] 7) Plasticizer: Paraffin oil

[0127] Referring to Figures 3 and 4, it can be seen that the damping characteristics of the material are improved as the PE content of EPDM decreases, the crosslinking density increases, and the degree of crystallinity of PP decreases.

[0128] Meanwhile, Figures 5 to 7 are electron microscope images showing the particle size of EPDM according to the ENB content of EPDM. Figures 5 to 7 are cases where the ENB content of EPDM is 5.7 wt%, 7.3 wt%, and 8.9 wt%, respectively.

[0129] Referring to FIGS. 5 to 7, it can be seen that as the ENB content of EPDM increases, the size of EPDM particles decreases to 2.10 μm, 1.67 μm, and 0.85 μm, respectively. Accordingly, the dispersibility of EPDM is improved, increasing friction loss at the interface between EPDM and PP, and simultaneously improving elasticity and permanent deformation, while also increasing damping.

[0130] [Experimental Example 3]

[0131] In a thermoplastic elastomer comprising 35.4 wt% EPDM and 13.7 wt% PP, the material damping characteristics and permanent compression set of the thermoplastic elastomer were measured according to changes in the content of the crosslink agent, the content of the plasticizer (process oil), and the content of the filler, and the results are shown in FIGS. 8 and 9. The material damping characteristics and permanent compression set were measured in the same manner as in Experimental Example 1.

[0132] In FIGS. 8 and 9, the Low, Mid, and High Crosslink agent contents are 0.76 parts by weight (0.34 wt%), 1.0 parts by weight (0.44 wt%), and 1.25 parts by weight (0.55 wt%), respectively, the Low, Mid, and High Process oil contents are 65 parts by weight (30.1 wt%), 75 parts by weight (33.2 wt%), and 85 parts by weight (36.0 wt%), respectively, the plasticizer contents are 65 parts by weight (30.1 wt%), 75 parts by weight (33.2 wt%), and 85 parts by weight (36.0 wt%), respectively, and the Low, Mid, and High Filler contents are 10 (4.71 wt%), 23.5 parts by weight (10.4 wt%), and 30 parts by weight (12.9 wt%), respectively.

[0133] Referring to Figures 8 and 9, it can be seen that damping performance improves when the content of the plasticizer is increased, but damping performance decreases when the content of the crosslinking agent is increased, and the content of the filler is unrelated to damping performance.

[0134] [Experimental Example 4]

[0135] For the thermoplastic elastomers prepared in Preparation Examples 1 to 5, changes in the coefficient of friction and changes in the magnitude of frictional vibration acceleration were measured, and the results are shown in FIGS. 10 and FIGS. 11 and summarized in Table 5.

[0136] coefficient of friction Max acceleration Preparation Example 1 0.278 2.44 Preparation Example 2 0.213 1.69 Preparation Example 3 0.235 1.38 Preparation Example 4 0.181 1.59 Preparation Example 5 0.208 1.03

[0137] Referring to Figures 10 and 11 and Table 4, it can be seen that when damping is improved, the static friction coefficient and the magnitude of frictional vibration are reduced.

[0138] Accordingly, it was confirmed that the EPDM / PP thermoplastic elastomer composition according to one embodiment has an effect of reducing frictional noise and vibration by increasing material damping. In the future, when the composition is applied to an inner belt weatherstrip, it is expected that the sealing performance can be improved, and the sensory quality can be enhanced by improving frictional vibration and noise. In addition, it is expected that various applications will be possible by controlling the physical properties of the final product according to changes in the composition of the constituent components.

[0139] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also included within the scope of the present invention. Explanation of the symbols

[0140] 1: Door panel 2: Door Glass 10: Weatherstrip 11: Closed lip 12: Flocking member 13: Body 15: Fixed part 16: Exterior wall sealing lip

Claims

Claim 1 The composition comprises 80 parts by weight of ethylene propylene diene monomer (EPDM) containing 5-ethylidene-2-norbornene (ENB) and polyethylene, 30 to 70 parts by weight of polypropylene, 20 to 40 parts by weight of a filler, and 60 to 90 parts by weight of a plasticizer, wherein the ethylene propylene diene monomer comprises 5% to 10% by weight of the 5-ethylidene-2-norbornene and 50% to 70% by weight of the polyethylene, based on the total weight of the ethylene propylene diene monomer, and the ethylene propylene diene monomer has a degree of crystallinity of 0% to 15.8% and a crosslinking density of 2.26 x 10⁻⁶ -4 mol / ml to 2.68 x 10⁻⁶ -4 A thermoplastic elastomer composition having mol / ml, a molecular weight distribution of 3.4 to 4.3, and the degree of crystallization of the polypropylene being 52% to 60%. Claim 2 delete Claim 3 A thermoplastic elastomer composition according to claim 1, wherein the ethylene propylene diene monomer comprises 8.9% to 10% by weight of the 5-ethylidene-2-norbornene and 50% to 58% by weight of the polyethylene propylene diene monomer based on the total weight of the ethylene propylene diene monomer. Claim 4 delete Claim 5 In claim 1, the thermoplastic elastomer composition comprises 30 to 35 parts by weight of the polypropylene. Claim 6 delete Claim 7 In claim 1, the thermoplastic elastomer composition comprises 85 to 90 parts by weight of the plasticizer. Claim 8 A thermoplastic elastomer composition according to claim 1, wherein the thermoplastic elastomer composition further comprises 0.1 to 1.25 parts by weight of a crosslinking agent. Claim 9 The thermoplastic elastomer composition according to claim 1, wherein the thermoplastic elastomer composition further comprises 0.1 to 0.5 parts by weight of a crosslinking agent, 0.1 to 0.5 parts by weight of an antioxidant, 1 to 3 parts by weight of a surface modifier, 1 to 3 parts by weight of a lubricant, 1 to 3 parts by weight of a crosslinking accelerator, 1 to 5 parts by weight of a UV stabilizer, or a mixture thereof. Claim 10 A thermoplastic elastomer manufactured from a thermoplastic elastomer composition according to claim 1, having a loss factor (Tan δ) of 0.139 or higher and a permanent compression set of 45.44% or lower. Claim 11 In claim 10, the thermoplastic elastomer is a thermoplastic elastomer having a loss factor (Tan δ) of 0.144 to 0.158 and a permanent compression set of 29.53% to 35.35%. Claim 12 In claim 10, the thermoplastic elastomer is a thermoplastic elastomer having a static friction coefficient of 0.9 or less, a kinetic friction coefficient of 0.69 or less, and a maximum acceleration of 2.44 g or less during stick-slip. Claim 13 A method for manufacturing a thermoplastic elastomer according to claim 10, comprising: a powder mixing step of mixing a powder containing a filler; an extruder feeding step of feeding ethylene propylene diene monomer (EPDM), polypropylene (PP), and the mixed powder into an extruder; a mixing step of mixing the ethylene propylene diene monomer and polypropylene in the extruder; and an EPDM dynamic crosslinking step of dynamically crosslinking the ethylene propylene diene monomer. Claim 14 Automotive weatherstrip comprising a thermoplastic elastomer according to paragraph 10.

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