Thermoplastic elastomer composition, and molded product, vehicle exterior mirror and vehicle containing same

Abstract

The invention provides a thermoplastic elastomer composition, a molded product containing the thermoplastic elastomer composition, a vehicle exterior mirror and a vehicle. Thermoplastic elastomer compositions exhibiting higher dual injection performance with PP, lower hardness, and lower storage modulus variation at lower temperatures are prepared by mixing appropriate amounts of a siloxane-based additive, a sliding agent, and a thermoplastic vulcanizate (TPV) in a thermoplastic elastomer. Siloxane-based additives and sliding agents are optimized to improve processability and mechanical properties while TPV components, including ethylene propylene diene monomer (EPDM) and polypropylene resin, contribute to enhanced elasticity and stability. The formulation balances flexibility and strength, wherein the siloxane additive improves surface properties and the sliding agent reduces friction. The composition is suitable for use in various applications requiring robust elastomer properties, especially in moldings in which low temperature resilience and high processability are critical. The total polypropylene content is controlled to ensure the optimal performance, and the optimal performance does not exceed 5wt%.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2024-0063477, filed with the Korean Intellectual Property Office on May 14, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to thermoplastic elastomer compositions and molding articles comprising said thermoplastic elastomer compositions, and more specifically to rubber seals for vehicle exterior mirrors. The disclosed thermoplastic elastomer compositions are designed to provide enhanced performance properties such as improved flexibility, weather resistance, and a reduced coefficient of friction, making them particularly suitable for automotive applications. These compositions are advantageous for the production of seals, gaskets, and other components requiring a combination of elastomer properties and easy processing in association with thermoplastics. These materials are tailored to withstand harsh environmental conditions, including exposure to UV radiation, temperature variations, and automotive fluids, thereby ensuring the long-term durability and performance of external automotive components such as exterior mirror seals. Background Technology

[0004] The exterior rearview mirrors of a vehicle are positioned on the outer front surface of the vehicle to ensure the driver's rearward visibility. However, in electric vehicles, the exterior rearview mirrors may generate wind noise. Figure 1 and Figure 2 As shown, a solution has been proposed to prevent wind noise by installing rubber seals around the exterior rearview mirrors.

[0005] However, as the exterior rearview mirror folds and unfolds, the rubber seals of the exterior rearview mirror may rub against each component that makes up the exterior rearview mirror (see...). Figure 2 When the exterior rearview mirror is unfolded, the front component of the housing, made of ASA material, contacts the rubber seals of the exterior rearview mirror; and when the exterior rearview mirror is folded, the body panel (including ABS material) component contacts the rubber seals of the exterior rearview mirror. This friction can cause abnormal noise or wear on the rubber seals of the exterior rearview mirror.

[0006] Typically, rubber seals for exterior rearview mirrors are prepared by blending styrene-ethylene-butadiene-styrene (SEBS) as a thermoplastic elastomer composition and polypropylene (PP) as a thermoplastic plastic. To address issues such as abnormal noise and wear, ensuring the material's wear resistance and low-friction properties is crucial. For this purpose, lubricants can be considered. However, when lubricants are added, the double-injection properties with PP may deteriorate, hardness may increase, thus increasing wear, and the storage modulus at lower temperatures may change more significantly.

[0007] Therefore, the physical properties of the rubber seals of the exterior rearview mirror can be maintained, while the dual injection performance with PP is increased, the hardness is reduced, and the change in storage modulus at lower temperatures is reduced. Summary of the Invention

[0008] This disclosure has been made to address the aforementioned problems in the prior art while maintaining the advantages achieved by the prior art.

[0009] One aspect of this disclosure provides a thermoplastic elastomer composition prepared by mixing an appropriate amount of a slip agent into a thermoplastic elastomer and a thermoplastic vulcanizate (TPV), the composition exhibiting higher two-injection performance with PP, lower hardness, and lower storage modulus change at lower temperatures.

[0010] The technical problems to be solved by this disclosure are not limited to those described above, and any other technical problems not mentioned herein will be clearly understood by those skilled in the art from the following description.

[0011] (1) This disclosure includes a thermoplastic elastomer composition comprising 100 parts by weight of a styrene-based thermoplastic elastomer, 25 to 55 parts by weight of a siloxane additive, 1 to 2.5 parts by weight of an amide lubricant, and 50 to 300 parts by weight of a thermoplastic vulcanizate.

[0012] (2) This disclosure provides a thermoplastic elastomer composition according to (1), wherein the thermoplastic vulcanizate comprises ethylene propylene diene monomer (EPDM) and polypropylene resin.

[0013] (3) This disclosure provides a thermoplastic elastomer composition according to (1) or (2), wherein the siloxane additive comprises a siloxane-based compound and a polypropylene resin.

[0014] (4) This disclosure provides a thermoplastic elastomer composition according to (3), wherein the siloxane additive comprises an amount of siloxane compound ranging from 3 wt% to 20 wt%.

[0015] (5) This disclosure provides a thermoplastic elastomer composition according to any one of (1) to (4), wherein the styrene-based thermoplastic elastomer comprises styrene-ethylene-butadiene-styrene (SEBS).

[0016] (6) This disclosure provides a thermoplastic elastomer composition according to (5), wherein the styrene-based thermoplastic elastomer comprises an amount of styrene ranging from 20 wt% to 50 wt%.

[0017] (7) This disclosure provides a thermoplastic elastomer composition according to any one of (1) to (6), wherein, based on 100 parts by weight of a styrene-based thermoplastic elastomer, a siloxane additive is included in an amount ranging from 30 parts by weight to 45 parts by weight.

[0018] (8) This disclosure provides a thermoplastic elastomer composition according to any one of (1) to (7), wherein an amide lubricant is contained in an amount ranging from 1.2 parts by weight to 2 parts by weight based on 100 parts by weight of a styrene-based thermoplastic elastomer.

[0019] (9) This disclosure provides a thermoplastic elastomer composition according to any one of (1) to (7), wherein the thermoplastic vulcanized rubber is contained in an amount ranging from 100 parts by weight to 200 parts by weight based on 100 parts by weight of a styrene-based thermoplastic elastomer.

[0020] (10) This disclosure provides a thermoplastic elastomer composition according to any one of (1) to (7), wherein the thermoplastic elastomer composition comprises up to 5 wt% polypropylene resin.

[0021] (11) This disclosure provides a molded article comprising a thermoplastic elastomer composition comprising any one of (1) to (10).

[0022] In some embodiments, the thermoplastic elastomer composition comprises about 100 parts by weight of a styrene-based thermoplastic elastomer, about 25 parts by weight to about 55 parts by weight of a siloxane additive, about 1 part by weight to about 2.5 parts by weight of an amide-based lubricant, and about 50 parts by weight to about 300 parts by weight of a thermoplastic vulcanizate. The thermoplastic vulcanizate may comprise ethylene propylene diene monomer (EPDM) and polypropylene resin. The siloxane additive may comprise a siloxane compound and polypropylene resin, wherein the siloxane compound is provided in an amount ranging from 3 wt% to 20 wt%. The styrene-based thermoplastic elastomer may comprise styrene-ethylene-butadiene-styrene (SEBS) with a styrene content ranging from 20 wt% to 50 wt%. Based on about 100 parts by weight of the styrene-based thermoplastic elastomer, the siloxane additive may be present in an amount ranging from about 30 parts by weight to about 45 parts by weight. Based on about 100 parts by weight of a styrene-based thermoplastic elastomer, the amide-based lubricant may be present in an amount ranging from about 1.2 parts by weight to about 2 parts by weight. Based on about 100 parts by weight of a styrene-based thermoplastic elastomer, the thermoplastic vulcanizate may be present in an amount ranging from about 100 parts by weight to about 200 parts by weight. Furthermore, the thermoplastic elastomer composition may contain up to 5 wt% of polypropylene resin.

[0023] In some embodiments, the thermoplastic elastomer composition comprises about 100 parts by weight of styrene-ethylene-butadiene-styrene (SEBS), about 30 parts by weight to about 45 parts by weight of a siloxane additive comprising a siloxane compound and polypropylene resin, about 1.2 parts by weight to about 2 parts by weight of an amide lubricant, and about 100 parts by weight to about 200 parts by weight of a thermoplastic vulcanizate comprising ethylene propylene diene monomer (EPDM) and polypropylene resin. This thermoplastic elastomer composition may also contain up to about 5 wt% of polypropylene resin.

[0024] In some embodiments, the thermoplastic elastomer composition comprises about 100 parts by weight of a styrene-based thermoplastic elastomer, about 45 parts by weight of a siloxane additive, about 2 parts by weight of an amide-based lubricant, and about 100 parts by weight of a thermoplastic vulcanizate. The styrene-based thermoplastic elastomer may comprise styrene-ethylene-butadiene-styrene (SEBS). The siloxane additive may comprise a siloxane compound and a polypropylene resin. The thermoplastic vulcanizate may comprise ethylene propylene diene monomer (EPDM) and a polypropylene resin. Furthermore, the thermoplastic elastomer composition may comprise up to 5 wt% of a polypropylene resin.

[0025] In some embodiments, the molded article comprises the thermoplastic elastomer composition of the first embodiment. The vehicle exterior rearview mirror may comprise the thermoplastic elastomer composition of the second embodiment. Furthermore, the vehicle may comprise the thermoplastic elastomer composition of the first embodiment.

[0026] As discussed, the method and system appropriately include the use of a controller or processor.

[0027] In another embodiment, vehicles comprising compositions as disclosed herein and their exterior rearview mirrors are provided. Attached Figure Description

[0028] The above and other objects, features, and advantages of this disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings:

[0029] Figure 1 This is a schematic view of the exterior rearview mirror used for a vehicle.

[0030] Figure 2 It shows along Figure 1 The view of the cross section obtained by the line A-A'.

[0031] Figure 3 The photograph was obtained by capturing the surface of the rubber seal of the exterior rearview mirror containing the thermoplastic elastomer composition according to Comparative Example 7.

[0032] Figure 4 The photograph was obtained by capturing the surface of the rubber seal of the exterior rearview mirror containing the thermoplastic elastomer composition according to Comparative Example 8.

[0033] Figure 5 This is a graph showing the measurement results after moving the thermoplastic elastomer composition according to Examples 1 to 4 and Comparative Example 9 in one direction while rubbing against a material containing ASA material and patterned with EMBO that forms the appearance of a side mirror, and measuring the coefficient of kinetic friction.

[0034] Figure 6 This is a graph showing the measurement results after measuring the coefficient of kinetic friction by moving a thermoplastic elastomer composition according to Examples 1 to 4 and Comparative Example 9 in one direction while rubbing against the ABS material forming the appearance of the side mirror. Detailed Implementation

[0035] In order to understand this disclosure, it will be described in more detail below.

[0036] In this context, the terms and words used in this specification and claims should not be interpreted as having their usual dictionary meanings, but rather as relating to the technical scope of the invention, based on the fact that the inventors can appropriately define the concepts of the terms to best interpret the invention.

[0037] The terminology used in this disclosure is provided for illustrative purposes only, and this disclosure is not limited thereto. Unless the context clearly indicates otherwise, the singular form is intended to include the plural form.

[0038] It should be understood that, as used herein, the terms “vehicle” or “of a vehicle” or other similar terms include motor vehicles in a broad sense, such as passenger cars, including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, vessels (including various boats and ships), aircraft, etc., and include hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuels derived from resources other than petroleum). As mentioned herein, a hybrid vehicle is a vehicle having two or more power sources, such as a gasoline-powered vehicle and an electric vehicle.

[0039] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to also include the plural forms. These terms are intended only to distinguish one component from another, and these terms do not limit the nature, order, or sequence of the constituent components. It should also be understood that when the terms “comprising” and / or “including” are used in this specification, they define the presence of the described features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term “and / or” includes any one and all combinations of one or more of the associated listed items. Throughout this specification, unless explicitly stated otherwise, the word “comprising” and variations such as “including” or “containing” will be understood to imply inclusion of the described elements, but do not exclude any other elements. Furthermore, the terms “unit,” “uniter,” “unitor,” and “module” described in the specification refer to a unit for performing at least one function and operation, and can be implemented by hardware components or software components and combinations thereof.

[0040] Although the exemplary implementation is described as using multiple units to perform the exemplary process, it should be understood that the exemplary process can also be performed by one or more modules. Furthermore, it should be understood that the term controller / control unit refers to a hardware device that includes a memory and a processor and is specifically programmed to perform the processes described herein. The memory is configured to store modules, and the processor is specifically configured to execute said modules to perform one or more processes further described below.

[0041] Furthermore, the control logic of this disclosure may be embodied in a non-volatile computer-readable medium containing executable program instructions that can be executed by a processor, controller, or the like. Examples of computer-readable media include, but are not limited to, ROM, RAM, optical disc (CD)-ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage devices. The computer-readable medium may also be distributed across a network-coupled computer system, enabling it to be stored and executed in a distributed manner, for example, via a telematics server or a controller area network (CAN).

[0042] Unless otherwise specified or obvious from the context, the term “about” as used herein shall be understood to mean within the normal tolerances in the field, such as within 2 standard deviations of the mean. “About” can be understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. All numerical values ​​provided herein are modified by the term “about” unless the context otherwise clarifies.

[0043] <Thermoplastic Elastomer Compositions>

[0044] The exterior rearview mirrors for vehicles are positioned on the outer front surface of the vehicle to ensure the driver's rearward visibility. However, when the vehicle is powered on, wind noise is introduced through the exterior rearview mirrors. Therefore, as... Figure 1 and Figure 2 As shown, a method has been proposed to prevent wind noise from being introduced through the exterior rearview mirror by providing a rubber seal.

[0045] However, as the exterior rearview mirror folds and unfolds, the rubber seals of the exterior rearview mirror may rub against each component that makes up the exterior rearview mirror (see...). Figure 2 When the exterior rearview mirror is unfolded, the front housing component (ASA material) comes into contact with the rubber seal of the exterior rearview mirror, and when the exterior rearview mirror is folded, the scalp component (including ABS material) comes into contact with the rubber seal of the exterior rearview mirror, thus causing abnormal noise or potentially abrading the rubber seal of the exterior rearview mirror.

[0046] Typically, rubber seals for exterior rearview mirrors are prepared by blending styrene-ethylene-butadiene-styrene (SEBS) as a thermoplastic elastomer composition and polypropylene (PP) as a thermoplastic plastic. To address the aforementioned problems (abnormal noise or wear issues), it is necessary to ensure wear resistance and low friction properties in the material's characteristics. For this purpose, a lubricant can be considered. However, when a lubricant is added, the double-injection performance with PP may deteriorate, the hardness may increase, thus increasing wear, and the storage modulus at lower temperatures may also change more significantly.

[0047] According to embodiments of the present disclosure, the thermoplastic elastomer composition comprises 100 parts by weight of a styrene-based thermoplastic elastomer; 25 to 55 parts by weight of a siloxane additive; 1 to 2.5 parts by weight of an amide lubricant; and 50 to 300 parts by weight of a thermoplastic vulcanizate.

[0048] According to one embodiment of this disclosure, when appropriate amounts of siloxane additives, appropriate amounts of lubricants, and appropriate amounts of thermoplastic vulcanizate (TPV) are mixed with thermoplastic styrene elastomer (TPS), the thermoplastic elastomer composition exhibits higher dual-injection performance and lower hardness relative to PP, as well as lower storage modulus change at lower temperatures.

[0049] The components constituting the thermoplastic elastomer composition are described in detail below.

[0050] 1. Styrene-based thermoplastic elastomers

[0051] According to embodiments of this disclosure, styrene-based thermoplastic elastomers can impart elasticity to thermoplastic elastomer compositions.

[0052] According to embodiments of this disclosure, the styrene-based thermoplastic elastomer can be a styrene-ethylene-butadiene-styrene (SEBS) rubber. In this case, the styrene-based thermoplastic elastomer can contain styrene provided in an amount ranging from 20% (wt%) to 50% by weight. Specifically, the styrene-based thermoplastic elastomer can contain at least 21 wt%, at least 22 wt%, at least 23 wt%, at least 24 wt%, or at least 25 wt%, and at most 48 wt%, at most 46 wt%, at most 44 wt%, at most 42 wt%, or at most 40 wt% of styrene. When this range is met, the thermoplastic elastomer composition can have enhanced mechanical properties and lower compression set.

[0053] According to embodiments of this disclosure, styrene-based thermoplastic elastomers can be included in the thermoplastic elastomer composition in an amount ranging from 20 wt% to 32 wt%. Specifically, styrene-based thermoplastic elastomers can be included in the thermoplastic elastomer composition in an amount of at least 21 wt%, at least 22 wt%, at least 23 wt%, at least 24 wt%, or at least 25 wt%. Furthermore, the content of styrene-based thermoplastic elastomers can be up to 31 wt%, at most 30 wt%, at most 29 wt%, at most 28 wt%, or at most 27 wt%. When this range is met, the thermoplastic elastomer composition can have an appropriate level of elasticity.

[0054] 2. Siloxane additives

[0055] According to embodiments of this disclosure, siloxane additives can impart abrasion resistance to thermoplastic elastomer compositions.

[0056] According to embodiments of this disclosure, the siloxane additive can be a masterbatch comprising a siloxane compound and a polypropylene resin. The masterbatch comprising polypropylene as the base resin can be obtained by mixing the siloxane compound with the polypropylene resin to achieve a uniform distribution of the siloxane compound.

[0057] According to embodiments of this disclosure, the siloxane compound can be a polydialkylsiloxane. Specifically, the siloxane compound can include at least one type of material selected from the group consisting of polydimethylsiloxane, polydiethylsiloxane, polydipropylsiloxane, and polydibutylsiloxane. Typically, the siloxane compound can be polydimethylsiloxane. Simultaneously, the siloxane compound can have a molecular weight of at least 200,000. When the above range is satisfied, the siloxane compound can impart excellent abrasion resistance to the thermoplastic elastomer composition.

[0058] According to embodiments of this disclosure, the siloxane compound can be included in an amount ranging from 40 wt% to 60 wt% based on the entire portion of the siloxane additive. Specifically, the siloxane compound can be included in an amount of at least 41 wt%, at least 42 wt%, at least 43 wt%, at least 44 wt%, or at least 45 wt%, and can be included in an amount of up to 59 wt%, up to 58 wt%, up to 57 wt%, up to 56 wt%, or up to 55 wt%. When this range is met, the thermoplastic elastomer composition can have significantly improved PP dual-injection properties and lower compression set.

[0059] According to embodiments of this disclosure, based on 100 parts by weight of a styrene-based thermoplastic elastomer, the thermoplastic elastomer composition may contain siloxane additives in an amount ranging from 25 parts by weight to 55 parts by weight. Specifically, based on 100 parts by weight of a styrene-based thermoplastic elastomer, the thermoplastic elastomer composition may contain siloxane additives in an amount of at least 26 parts by weight, at least 27 parts by weight, at least 28 parts by weight, at least 29 parts by weight, or at least 30 parts by weight. Additionally, based on 100 parts by weight of a styrene-based thermoplastic elastomer, the thermoplastic elastomer composition may contain siloxane additives in an amount of up to 53 parts by weight, at most 51 parts by weight, at most 49 parts by weight, at most 47 parts by weight, or at most 45 parts by weight. When siloxane additives are contained in amounts below the aforementioned ranges, the surface modification effect is weak. Therefore, the abrasion resistance of the thermoplastic elastomer composition may deteriorate. When the content of siloxane additives exceeds the above range, the appearance properties may deteriorate due to the incompatibility between the components of the thermoplastic elastomer composition.

[0060] 3. Amide-based lubricants

[0061] According to embodiments of this disclosure, amide-based lubricants can impart sliding properties to thermoplastic elastomer compositions.

[0062] According to one embodiment of this disclosure, the amide-based lubricant may comprise an amide compound, and the amide compound may comprise at least one type of material selected from the group consisting of behenamide, erucamide, oleamide, and octadecylamide. Typically, the amide compound may comprise oleamide (C... 18 H 35 ON).

[0063] According to embodiments of this disclosure, based on 100 parts by weight of a styrene-based thermoplastic elastomer, the thermoplastic elastomer composition may contain an amount of amide-based lubricant ranging from 1 part by weight to 2.5 parts by weight. Specifically, based on 100 parts by weight of a styrene-based thermoplastic elastomer, the thermoplastic elastomer composition may contain at least 1.05 parts by weight, at least 1.1 parts by weight, at least 1.15 parts by weight, or at least 1.2 parts by weight of amide-based lubricant. Furthermore, based on 100 parts by weight of a styrene-based thermoplastic elastomer, the thermoplastic elastomer composition may contain up to 2.4 parts by weight, up to 2.3 parts by weight, up to 2.2 parts by weight, up to 2.1 parts by weight, or up to 2 parts by weight of amide-based lubricant. When the content of the amide-based lubricant is below the above range, the surface modification effect is weak. Therefore, the sliding properties of the thermoplastic elastomer composition may be reduced. When the content of the siloxane additive exceeds the above range, the appearance properties of the thermoplastic elastomer composition may deteriorate.

[0064] 4. Thermoplastic vulcanized rubber

[0065] According to embodiments of this disclosure, thermoplastic vulcanized rubber can ensure that the compression set and hardness of the thermoplastic elastomer composition are at appropriate levels.

[0066] According to embodiments of this disclosure, thermoplastic vulcanizates can be prepared by dynamically vulcanizing a mixture comprising ethylene propylene diene monomer (EPDM) and polypropylene resin in the form of vulcanizates.

[0067] According to embodiments of this disclosure, the thermoplastic vulcanized rubber has a Shore A hardness in the range of 45 to 60.

[0068] According to embodiments of this disclosure, based on 100 parts by weight of a styrene-based thermoplastic elastomer, the thermoplastic elastomer composition may contain an amount ranging from 50 parts by weight to 300 parts by weight of thermoplastic vulcanized rubber. Specifically, based on 100 parts by weight of a styrene-based thermoplastic elastomer, the thermoplastic elastomer composition may contain at least 60 parts by weight, at least 70 parts by weight, at least 80 parts by weight, at least 90 parts by weight, or at least 100 parts by weight of thermoplastic vulcanized rubber. Furthermore, based on 100 parts by weight of a styrene-based thermoplastic elastomer, the thermoplastic elastomer composition may contain up to 280 parts by weight, at most 260 parts by weight, at most 240 parts by weight, at most 220 parts by weight, or at most 200 parts by weight of thermoplastic vulcanized rubber. When the content of thermoplastic vulcanized rubber is below the above range, the compression set of the thermoplastic elastomer composition may deteriorate. When the content of thermoplastic vulcanized rubber exceeds the above range, the hardness of the thermoplastic elastomer composition may unnecessarily increase.

[0069] 5. Polypropylene resin

[0070] According to one embodiment of this disclosure, in addition to the styrene-based thermoplastic elastomer, siloxane additives, amide-based lubricants, and thermoplastic vulcanized rubber components constituting the thermoplastic elastomer composition, the polypropylene resin included in the thermoplastic elastomer composition can be considered as additionally included polypropylene resin and / or polypropylene resin included in the siloxane additives and the thermoplastic vulcanized rubber.

[0071] In other words, when polypropylene resin is additionally included in addition to the components constituting the thermoplastic elastomer composition, the polypropylene resin included in the thermoplastic elastomer composition can be considered as the additionally included polypropylene resin and / or the polypropylene resin included in the siloxane additives and the polypropylene resin included in the thermoplastic vulcanizate. When no polypropylene resin is additionally included in addition to the components constituting the thermoplastic elastomer composition, the polypropylene resin included in the thermoplastic elastomer composition can be considered as the polypropylene resin included in the siloxane additives and the polypropylene resin included in the thermoplastic vulcanizate.

[0072] According to one embodiment, based on the entire portion of the thermoplastic elastomer composition, the thermoplastic elastomer composition may contain at least 5 wt%, and specifically in the range of 0.5 wt% to 4.5 wt%, an amount of polypropylene resin.

[0073] 6. Other additives

[0074] According to embodiments of this disclosure, the thermoplastic elastomer composition may contain other additives. The additives may include materials of at least one type selected from the group consisting of: plasticizers, fillers, UV stabilizers, hydrolytic stabilizers, mold release agents, antistatic agents, crosslinking agents, antibacterial agents, processing aids, metal deactivators, inhibitors, friction-resistant agents, and abrasion-resistant agents.

[0075] Additives may include a variety of additives, as long as they are used within the technical field of this disclosure. Furthermore, those skilled in the art can select the additives included in this disclosure according to their intended purpose.

[0076] <Molded Products>

[0077] This disclosure provides molded articles comprising thermoplastic elastomer compositions. For example, these molded articles can be used in various industrial sectors, such as various electrical and electronic products and vehicle parts. For example, as... Figure 2 As shown, molded parts can be used for rubber seals on vehicle exterior rearview mirrors.

[0078] When the thermoplastic elastomer composition according to embodiments of this disclosure is applied to the rubber seal of a vehicle exterior rearview mirror, such as Figure 1 and Figure 2 As shown, the thermoplastic elastomer composition can ensure excellent properties of slip characteristics, compression set, PP adhesion, and abrasion resistance at low hardness (up to 30 Shore A). Therefore, the thermoplastic elastomer composition according to embodiments of this disclosure can improve stick-slip phenomena without causing abnormal noise associated with materials such as ABS or ASA.

[0079] Embodiments of this disclosure will be described in detail below so that those skilled in the art can readily reproduce them. However, this disclosure may be implemented in various forms and is not limited to the embodiments described herein.

[0080] Examples and Comparative Examples

[0081] The components used in the embodiments and comparative examples of this disclosure are described below.

[0082] (A) Polypropylene resinThe polypropylene resin used is classified as an HSPP block copolymer and has a melt index of up to 1 g / 10 min, an elongation of at least 600%, a hardness grade ranging from at least 80R to at most 90R, and a melting point of at least 152°C to at most 156°C.

[0083] (B) Styrene-based thermoplastic elastomers Styrene-ethylene-butadiene-styrene (SEBS) rubber is used, which has 33% styrene, a specific gravity of at least 0.91, and a toluene viscosity in the range of 1500 cp to 2500 cp (20 wt%, 25°C).

[0084] (C) Siloxane additives The additive used is a mixture of homopolymer polypropylene resin with a melt flow index of 12 and ultra-high molecular weight (UHMW) siloxane compounds, and includes a masterbatch containing 50% siloxane compounds.

[0085] (D) Amide-based lubricants The additives used are amide materials derived from fatty acids, having at least 97% amide content, 80% to 90% iodine value, and a melting point in the range of 71°C to 76°C.

[0086] (E) Thermoplastic vulcanized rubber Thermoplastic vulcanizate is obtained by dynamically vulcanizing a mixture of EPDM and polypropylene resin, containing 39 wt% EPDM, with a Shore A hardness ranging from 45 to 60, and a melt flow index of up to 80 (230°C; 10 kg) and a melting point of 153°C.

[0087] (F) UV stabilizer A mixture of an amine-based light stabilizer (HALS: UV-944) with a melting point in the range of 110°C to 130°C and a molecular weight in the range of 2100 g / mol to 3000 g / mol and a UV absorber (UV-326) with a melting point in the range of 137°C to 142°C and a molecular weight of 315 was used as a UV stabilizer.

[0088] (G) Plasticizer High molecular weight paraffin oil with a specific gravity of 0.87, a flash point of at least 280°C, and a kinematic viscosity (40°C) in the range of 160 cp to 190 cp was used as a plasticizer.

[0089] (H) packing The filler used contains heavy calcium carbonate with an average particle size of 6.5 micrometers.

[0090] Thermoplastic elastomer (TPS) ): Uses a mixture of polypropylene resin and styrene-ethylene-butadiene-styrene (SEBS) rubber as the thermoplastic elastomer (TPS) without containing thermoplastic vulcanizing agents.

[0091] Thermoplastic elastomer compositions are produced in granular form by mixing the components with the contents and proportions described in Tables 1 and 2 using an extruder at temperatures ranging from 150°C to 200°C and by cutting.

[0092] Experimental Example 1 - Measurement of Physical Properties

[0093] The pellets prepared in the Examples and Comparative Examples were extruded and injected to prepare test samples, and their physical properties were measured as follows and then described in Tables 1 and 2.

[0094] Hardness (Shore A): Hardness was measured using a TECLOCK GC610 STAND hardness tester and a Mitutoyo Shore A hardness tester, in accordance with ISO 7619.

[0095] 100% Modulus: According to ISO 37, after stretching the specimen through a rubber UTM (DUT-500C) device at a temperature of 25°C and a crosshead speed of 500 mm, the tensile stress (100% modulus) is measured when the specimen is 100% stretched.

[0096] Tensile strength: According to ISO 37, after stretching the specimen through a rubber UTM (DUT-500C) device at a temperature of 25°C and a crosshead speed of 500 mm, the tensile strength is measured at the point where the specimen is cut.

[0097] Elongation: According to ISO 37, after stretching the specimen through a rubber UTM (DUT-500C) device at a temperature of 25°C and a crosshead speed of 500 mm / min, the elongation is measured at the point where the specimen is cut.

[0098] Compression deformation: According to ISO 815, the specimen is compressed by 25% and placed in an oven at 70°C for 22 hours, the compression is released, and the test is performed under the condition of placing the specimen at 25°C for 30 minutes. The thickness of the specimen is measured before and after the test to calculate the compression deformation using the following Equation 1.

[0099] Equation 1

[0100]

[0101] In Equation 1, H0 represents the specimen thickness before compression, H1 represents the specimen thickness during compression, and H2 represents the specimen thickness after compression. In this disclosure, lower compressive deformation demonstrates excellent performance.

[0102] Weight change after glass abrasion (abrasion resistance): Under a 500g load, the sample was repeatedly abraded 2500 times using the edge of the glass, and the weight change of the sample was measured. A larger change in sample weight indicates a deterioration in abrasion resistance.

[0103] Stationary and kinematic friction coefficients: For each embodiment / comparative example, two test specimens with dimensions of 5 mm x 100 mm were collected, and after moving the two specimens 200 mm under a load of 1 kg and a test speed of 50 mm / min, the stationary and kinematic friction coefficients of the two specimens were measured. The kinematic friction coefficient was measured in the range between 50 mm and 150 mm, and the average of the maximum and minimum kinematic friction coefficients was measured. A lower kinematic friction coefficient indicates superior sliding characteristics.

[0104] PP Adhesion Properties: Tensile specimens for evaluating adhesion properties are prepared by injecting and bonding the relevant material to a PP sample. Adhesion properties are measured after tensile testing using a rubber UTM (DUT-500C) device at 25°C and a crosshead speed of 500 mm, according to ISO 37. Higher tensile stress when the PP sample separates from the relevant material indicates superior adhesion properties.

[0105] Table 1

[0106]

[0107] Table 2

[0108]

[0109] Reference Figure 1 and Figure 2 It can be recognized that, compared with Comparative Examples 1 to 9, in which no thermoplastic elastomer composition components are provided in appropriate amounts, Examples 1 to 4 exhibit superior sliding properties, compression set, PP adhesion properties and abrasion resistance with lower hardness (up to 34 Shore A). Examples 1 to 4 provide thermoplastic elastomer composition components in appropriate amounts, namely styrene-based thermoplastic elastomers, siloxane additives, amide-based lubricants and thermoplastic vulcanizates.

[0110] Specifically, it can be recognized that, compared with the examples, Comparative Examples 1, 3 to 5 and 9, which do not contain thermoplastic vulcanized rubber, exhibit higher compression set and lower abrasion resistance.

[0111] Furthermore, it can be recognized that, compared with the examples, in Comparative Example 2, which contains thermoplastic vulcanized rubber but not siloxane additives and amide lubricants, the abrasion resistance is significantly deteriorated.

[0112] It can be recognized that in Comparative Example 6, which contains an excessive amount of thermoplastic vulcanized rubber, the hardness is excessively increased.

[0113] It can be recognized that in Comparative Example 7, which contains siloxane additives in excessive amounts, the appearance is defective due to surface delamination of the sample, such as... Figure 3 As shown.

[0114] It can be recognized that in Comparative Example 8, which contains an excessive amount of amide-based lubricant, the appearance is defective due to oil transfer to the surface of the sample, such as... Figure 4 As shown.

[0115] Experimental Example 2 - Identified Stick-Slip Improvement

[0116] like Figure 2 As shown, the coefficient of kinetic friction was measured by moving the thermoplastic elastomer composition according to Examples 1 to 4 and Comparative Example 9 in one direction while rubbing it against the material forming the appearance of the side mirror (containing ASA material patterned with EMBO and ABS material). Then, Figure 5 and Figure 6 The measurement results are shown in the figure. When the coefficient of kinetic friction increases with change in displacement, it indicates an increase in stick-slip; conversely, when the coefficient of kinetic friction decreases, it indicates an improvement in stick-slip. With increased stick-slip, friction on the contact surfaces between the rubber and plastic materials may increase.

[0117] from Figure 5 and Figure 6 It can be recognized that, compared with Comparative Example 9, which does not contain thermoplastic vulcanized rubber, the stick-slip phenomenon is improved according to Examples 1 to 4 because the coefficient of kinetic friction decreases with the change of moving displacement.

[0118] Experimental Example 3 - Identified Improvement in Damping Characteristics.

[0119] For the thermoplastic elastomer compositions of Example 3 and Comparative Example 9, dynamic strain of 0.2% and temperature scan at 10 Hz were performed using a Q850 instrument (DMA) from TA Instruments. The changes in storage modulus between 23°C and -40°C were then calculated, and the results are described in Table 3 below.

[0120] Table 3

[0121]

[0122] Referring to Table 3, it can be recognized that, compared with Comparative Example 9 which does not contain thermoplastic vulcanized rubber, the damping characteristics are ensured due to the lower rate of change of storage modulus according to Example 3.

[0123] Experimental Example 4 - Results Identified After Applying to Real Vehicles

[0124] The thermoplastic elastomer compositions according to Examples 1, 3 and Comparative Example 9 were applied to Figure 1 and Figure 2 The rubber seals of the exterior rearview mirror are shown. Abnormal noise caused by the rubber seals of the exterior rearview mirror was then evaluated by repeatedly folding and unfolding the mirror 3,000 times. Furthermore, the wear condition of the rubber seals of the exterior rearview mirror was evaluated by repeatedly folding and unfolding the mirror 3,000 times, and the evaluation results are described in Table 4.

[0125] Table 4

[0126]

[0127] Referring to Table 4, it can be recognized that when the thermoplastic elastomer compositions according to Examples 1 and 3 are compared with the thermoplastic elastomer composition according to Comparative Example 9, abnormal noise and wear phenomena are improved without the application of lubricant.

[0128] As described above, according to this disclosure, the thermoplastic elastomer composition exhibits higher dual-injection performance with PP, lower hardness, and lower storage modulus change at lower temperatures.

[0129] Exterior rearview mirror seals incorporating thermoplastic elastomer compositions according to this disclosure exhibit higher dual-injection performance, lower hardness, and lower storage modulus change at lower temperatures compared to PP.

[0130] While this disclosure has been described above with reference to exemplary embodiments and accompanying drawings, it is not limited thereto. Various modifications and alterations may be made by those skilled in the art to which this disclosure pertains without departing from the spirit and scope of this disclosure as claimed in the appended claims.

Claims

1. A thermoplastic elastomer composition comprising: 100 parts by weight of a styrene-based thermoplastic elastomer; Siloxane additives in amounts ranging from 25 to 55 parts by weight; An amide-based lubricant in an amount ranging from 1 part by weight to 2.5 parts by weight; and Thermoplastic vulcanized rubber in amounts ranging from 50 parts by weight to 300 parts by weight.

2. The thermoplastic elastomer composition according to claim 1, wherein, The thermoplastic vulcanizate comprises ethylene propylene diene monomer (EPDM) and polypropylene resin.

3. The thermoplastic elastomer composition according to claim 1, wherein, The siloxane additives comprise siloxane compounds and polypropylene resin.

4. The thermoplastic elastomer composition according to claim 3, wherein, The siloxane additive comprises siloxane compounds provided in amounts ranging from 3 wt% to 20 wt%.

5. The thermoplastic elastomer composition according to claim 1, wherein, The styrene-based thermoplastic elastomers include styrene-ethylene-butadiene-styrene (SEBS).

6. The thermoplastic elastomer composition according to claim 5, wherein, The styrene-based thermoplastic elastomer contains styrene in an amount ranging from 20 wt% to 50 wt%.

7. The thermoplastic elastomer composition according to claim 1, wherein, The siloxane additive is contained in an amount ranging from 30 to 45 parts by weight, based on 100 parts by weight of the styrene-based thermoplastic elastomer.

8. The thermoplastic elastomer composition according to claim 1, wherein, The amide-based lubricant is contained in an amount ranging from 1.2 parts by weight to 2 parts by weight, based on 100 parts by weight of the styrene-based thermoplastic elastomer.

9. The thermoplastic elastomer composition according to claim 1, wherein, Based on 100 parts by weight of the styrene-based thermoplastic elastomer, the thermoplastic vulcanized rubber is contained in an amount ranging from 100 parts by weight to 200 parts by weight.

10. The thermoplastic elastomer composition according to claim 1, wherein, The thermoplastic elastomer composition contains up to 5 wt% polypropylene resin.

11. A thermoplastic elastomer composition comprising: 100 parts by weight of styrene-ethylene-butadiene-styrene (SEBS); A siloxane additive comprising a siloxane compound and a polypropylene resin, wherein the amount of the siloxane additive is in the range of 30 parts by weight to 45 parts by weight. An amount of amide-based lubricant ranging from 1.2 parts by weight to 2 parts by weight; and Thermoplastic vulcanizate, wherein the thermoplastic vulcanizate comprises ethylene propylene diene monomer (EPDM) and polypropylene resin, and the amount of the thermoplastic vulcanizate is in the range of 100 parts by weight to 200 parts by weight.

12. The thermoplastic elastomer composition according to claim 11, wherein, The thermoplastic elastomer composition contains up to 5 wt% polypropylene resin.

13. A thermoplastic elastomer composition comprising: 100 parts by weight of a styrene-based thermoplastic elastomer; 45 parts by weight of siloxane additives; 2 parts by weight of amide-based lubricant; and 100 parts by weight of thermoplastic vulcanized rubber.

14. The thermoplastic elastomer composition according to claim 13, wherein, The styrene-based thermoplastic elastomers include styrene-ethylene-butadiene-styrene (SEBS).

15. The thermoplastic elastomer composition according to claim 13, wherein, The siloxane additives comprise siloxane compounds and polypropylene resin.

16. The thermoplastic elastomer composition according to claim 13, wherein, The thermoplastic vulcanizate comprises ethylene propylene diene monomer (EPDM) and polypropylene resin.

17. The thermoplastic elastomer composition according to claim 13, wherein, The thermoplastic elastomer composition contains up to 5 wt% polypropylene resin.

18. A molded article comprising the thermoplastic elastomer composition of claim 1.

19. A vehicle exterior rearview mirror comprising the thermoplastic elastomer composition of claim 1.

20. A vehicle comprising the thermoplastic elastomer composition of claim 1.

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