KR20150061095A - Thermoplastic elastomer composition - Google Patents

Abstract

The present invention relates to a thermoplastic elastomer composition, including: 24.5-26.0 wt% of ethylene propylene diene monomer (EPDM) rubber; 42.0-45.0 wt% of polypropylene (PP); 24.0-26.0 wt% of paraffin oil; 0.3-0.4 wt% of peroxide cross-linking agents; 0.1-0.2 wt% of antioxidant; and 5.0-6.0 wt% of inorganic fillers. The thermoplastic elastomer composition is allowed to improve bellows bowing of a gear box caused by thermal history after blow molding and accordingly minimizes creation of noise caused by modification when driving steering systems while securing rigidity through increase of cross-linking level, thereby having a good long-term heat resistance.

Description

[0001] Thermoplastic elastomer composition [0002]

TECHNICAL FIELD The present invention relates to a thermoplastic elastomer composition, and more specifically to a thermoplastic elastomer composition excellent in rigidity and long-term heat resistance.

Recently, in the field of automobiles, the demand for lighter weight and eco-friendliness has led to the replacement of metal and bridged rubber parts with plastic parts. Accordingly, utilization of thermoplastic elastomer materials which have low specific gravity, good workability and can be recycled is increasing.

On the other hand, the gearbox bellows converts the turning motion of the steering wheel into a linear reciprocating motion when the driver rotates the steering wheel, determines the traveling direction of the vehicle by rotating the front wheel of the vehicle to the left and right, It plays a role of involvement. In particular, it protects Inner Ball Joint from dust or foreign matter to ensure stable running.

Japanese Unexamined Patent Publication Nos. 1999-323110, 1999-323110, and 2001-247752 disclose a method for increasing the melt viscosity of a thermoplastic elastomer resin to a level at which blow molding is easy. In the thermoplastic polyester elastomer, Or more of an epoxy compound.

In the production of gearbox bellows for use in such a steering apparatus for a vehicle, a TPEE (thermoplastic ester) series, which is a composition of an aliphatic polyester and an aromatic polyester, which are thermoplastic elastomer compositions, or EPDM (ethylene propylene diene rubber) TPV (thermoplastic olefin elastomer) which is a composition of polypropylene) is mainly used, and blow molding is mainly utilized.

However, in the case of a gear box bellows, external deformation due to thermal hysteresis frequently occurs during operation of the product, and when aging of the vehicle progresses, product performance due to long-term use may deteriorate, that is, appearance wear and air leaks may occur. In addition, the price of TPEE series is high and defective rate is high in blow molding, so improvement is required.

Therefore, in order to solve the above problems, there is an urgent need to develop an invention that meets the needs of the thermoplastic elastomer composition as an automobile industry component, which has been increasing in recent years.

Accordingly, the inventor of the present invention has made efforts to develop a gear box bellows for use in a steering system for a vehicle, in which a thermoplastic elastomer which is a composition of EPDM (ethylene propylene diene rubber) and polypropylene (polypropylene) The present invention has been accomplished to achieve the effect of minimizing the deformation due to thermal history during operation by utilizing TPV.

An object of the present invention is to provide a thermoplastic elastomer composition which is excellent in rigidity and long-term heat resistance and is suitable for automobile parts.

Another object of the present invention is to provide a thermoplastic elastomer composition having improved warping and minimizing occurrence of noise due to deformation when the steering apparatus is driven.

Another object of the present invention is to provide a gear box bellows and other automobile parts which are excellent in rigidity and long-term heat resistance by applying the thermoplastic elastomer composition.

The above and other objects of the present invention can be achieved by the present invention described below.

One aspect of the present invention is a composition comprising 24.5 to 26.0% by weight ethylene propylene diene rubber (EPDM); 42.0 to 45.0% by weight of polypropylene (PP); 24.0 to 26.0% by weight of paraffin oil; From 0.3 to 0.4% by weight of a peroxide crosslinking agent; 0.1 to 0.2% by weight of an antioxidant; And 5.0 to 6.0% by weight of an inorganic filler.

In an embodiment, the polypropylene (PP) is a homo-polypropylene having a melt flow index (Melt Flow Index, 230 占 폚, 2.16 kg) of more than 0 and less than or equal to 2.0 g / 10 min; And (b2) a block co-polymer having a melt flow index (Melt Flow Index, 230 ° C, 2.16 kg) of more than 0 and not more than 0.5 g / 10 min.

In an embodiment, the weight ratio of (b1) homopolypropylene to (b2) block copolymer may be in the range of 1.5: 1 to 2: 1.

In an embodiment, the paraffin oil may have a kinematic viscosity at 40 DEG C of 170 cSt or more.

In an embodiment, the composition may further comprise at least one additive selected from the group consisting of light stabilizers, crosslinking aids, pigments, lubricants and waxes.

Another aspect of the present invention relates to a vehicle component molded from the thermoplastic elastomer composition.

In an embodiment, the automotive component may be an automotive gear box bellows.

In an embodiment, the forming may be blow molding.

The thermoplastic elastomer composition according to the present invention is improved in warpage of the gear box bellows due to thermal history after blow molding, minimizes the occurrence of noise due to deformation during driving of the steering device, secures rigidity by increasing the degree of crosslinking, .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a side face of a gear box bellows using a thermoplastic elastomer composition according to one embodiment of the present invention. FIG.
2 is a schematic view showing a cross section of a gear box bellows using a thermoplastic elastomer composition according to one embodiment of the present invention.

Embodiments of the present application will now be described in more detail with reference to the accompanying drawings. However, the techniques disclosed in the present application are not limited to the embodiments described herein but may be embodied in other forms. It should be understood, however, that the embodiments disclosed herein are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the width, thickness, and the like of the components are enlarged in order to clearly illustrate the components of each device.

In addition, although only a part of the components is shown for convenience of explanation, those skilled in the art will be able to easily grasp the rest of the components. It is to be understood that when an element is described above as being located above or below another element, it is to be understood that the element may be directly on or under another element, It means that it can be done. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. In the drawings, the same reference numerals denote substantially the same elements.

Meanwhile, the meaning of the terms described in the present application should be understood as follows. The terms " first " or " second " and the like are intended to distinguish one element from another and should not be limited by these terms. For example, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

Also, the singular " include " should be understood to include plural representations, unless the context clearly dictates otherwise, and the terms & Parts or combinations thereof, and does not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

Further, in carrying out the method or the manufacturing method, the respective steps of the method may take place differently from the stated order unless clearly specified in the context. That is, each process may occur in the same order as described, may be performed substantially concurrently, or may be performed in the opposite order.

Hereinafter, the present invention will be described in more detail.

Thermoplastic elastomer composition

In one aspect of the present invention, the thermoplastic elastomer composition comprises 24.5 to 26.0% by weight of ethylene propylene diene rubber (EPDM); 42.0 to 45.0% by weight of polypropylene (PP); 24.0 to 26.0% by weight of paraffin oil; From 0.3 to 0.4% by weight of a peroxide crosslinking agent; 0.1 to 0.2% by weight of an antioxidant; And 5.0 to 6.0% by weight of an inorganic filler.

The thermoplastic elastomer composition according to the present invention is improved in warpage of the gear box bellows due to thermal history after blow molding, minimizes the occurrence of noise due to deformation during driving of the steering device, secures rigidity by increasing the degree of crosslinking, And since it can be recycled, it is possible to grind and recycle bur and formed defective products generated in the production of the product by injection molding or vacuum molding, thereby providing environmental protection and cost saving There is an advantage.

Each component constituting the thermoplastic elastomer composition of the present invention will be specifically described below.

(A) Ethylene propylene diene rubber (EPDM)

The amount of the ethylene propylene diene rubber (EPDM) (A) used in the composition of the present invention is preferably from 24.5 to 26.0% by weight, and more preferably from 24.6 to 25.0% by weight. When the content is less than 24.5% by weight, the elasticity of the product is lowered and the durability of the product is lowered. When the content is more than 26.0% by weight, the product flowability is decreased due to an increase in the molecular weight (viscosity) of the rubber component.

(B) Polypropylene

The polypropylene (B) may have a degree of crystallinity of 40 to 50.

In an embodiment, the polypropylene (B) comprises (b1) homo-polypropylene having a melt flow index (Melt Flow Index, 230 DEG C, 2.16 kg) And (b2) a block co-polymer having a melt flow index (Melt Flow Index, 230 占 폚, 2.16 kg) of more than 0 and less than or equal to 0.5.

The homopolypropylene (b1) may have a crystallinity of 48 to 50, and the block copolymer (b2) may have a crystallinity of 42 to 44.

The block copolymer (b2) is a copolymer of an unsaturated monomer polymerizable with propylene, wherein the polymerizable unsaturated monomer is at least one monomer selected from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, C1-20 alkyl acrylate containing linear, branched or cyclic chains such as acrylate and tert-butyl acrylate, C6-20 aryl acrylate, 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate Di- or poly (ethylene glycol) monomers containing a selectively etherified hydroxy end, such as (meth) acrylates of ethylene glycol, diethylene glycol, or polyethylene glycol, ) (Meth) acrylate, undecyl acrylamide or N-octylacrylamide. (Meth) acrylamides, vinyl ethers such as vinyl isobutyl ether, specific substituted styrenes, fluoro such as acrylic esters containing perfluoroalkyl chains such as perfluorooctyl ethyl acrylate, or Acrylic or vinyl monomers containing perfluoro groups, acrylic or vinyl silicone monomers such as acryloxypropyl polydimethyl siloxane, and the like.

In this case, the (b2) block copolymer may contain 1 to 99% by weight of propylene and 1 to 99% by weight of a polymerizable unsaturated monomer. Within the above range, the thermoplastic elastomer composition of the present invention can minimize deformation due to thermal history, has excellent rigidity and long-term heat resistance, and has an advantage that the moldability of the polypropylene copolymer can be improved.

In the polypropylene (B), the weight ratio of (b1) homopolypropylene and (b2) block copolymer may be 1.5: 1 to 2: 1. Blow molding formability and high strength, high impact and oil resistance of the gear box bellows can be improved in the above range.

The polypropylene (B) is contained in an amount of 42.0 to 45.0% by weight in 100% by weight of the whole composition. If the above content range is less than 42.0 wt%, the product rupture occurs during blow molding and molding is difficult. If the content exceeds 45.0 wt%, it is difficult to operate the gear box bellows due to the increase in hardness of the finished product. Difficulties arise. And preferably 43.5 to 44.9% by weight.

(C) Paraffin oil

In an embodiment, the paraffin oil may have a kinematic viscosity at 40 DEG C of 170 cSt or more, preferably 170 to 300 cSt, and more preferably 180 to 250 cSt.

Within the above range, it is possible to promote the processability in the production of the thermoplastic elastomer composition and promote the dispersion of the carbon black or pigment and filler filler. Further, the hardness of the thermoplastic elastomer can be reduced to increase plasticity and moldability.

The paraffin oil is included in the total composition in an amount of 24.0 to 26.0% by weight. If the content range is less than 24.0% by weight, the flowability is poor in blow molding, which may cause defective molding or malfunction. When the content exceeds 26.0% by weight, flowability increases, And the product thickness variation occurs during air blow for product shape molding. Preferably, the paraffin oil is 24.5 to 25.0% by weight.

(D) a peroxide crosslinking agent

The peroxide crosslinking agent serves to crosslink the rubber portion so as to exhibit the physical properties of the thermoplastic elastomer composition.

The thermoplastic elastomer composition material is basically composed of a rubber segment that is a soft segment and a thermoplastic resin that is a hard segment. The peroxide crosslinking agent crosslinks the rubber segment, which is a soft segment, to form a rubber-like viscous and elastic Property.

The crosslinking can be carried out using a twin-screw extruder (twin extruder). Further, the peroxide crosslinking agent can be preferably used because it does not have a problem due to moisture absorption as compared with a phenolic crosslinking agent or a silane crosslinking agent.

Examples of the peroxide crosslinking agent include peroxide crosslinking agents, hydroperoxide crosslinking agents, and azo compound crosslinking agents such as dibenzoyl peroxide crosslinking agent, cyclic hydroperoxide crosslinking agent, cyclohexanone peroxide crosslinking agent, di-tert-butyl peroxide crosslinking agent, Cyclohexylsulfonyl acetyl peroxide cross-linking agent, diisopropyl percarbonate cross-linking agent, tert-butyl peroxyl cross-linking agent, benzopinacol cross-linking agent and the like can be used.

The peroxide crosslinking agent is used in an amount of 0.3 to 0.4% by weight. When the content range is less than 0.3 wt%, crosslinking is not sufficiently performed, and the physical properties and viscoelastic properties of the article are lowered. When the content is more than 0.4 wt%, too much crosslinking occurs and appearance defects such as fish eyes are observed Which may cause defective appearance of the blow molding machine and poor moldability. And preferably 0.38 to 0.40% by weight.

(E) Antioxidant

When a thermoplastic elastomer composition material is prepared, it is generally prepared by dynamic cross-linking using a twin-screw extruder (twin extruder). In this case, a high shearing force occurs at a processing temperature of 200 ° C or higher. In the present invention, antioxidant is applied to prevent oxidation of the rubber portion of the soft segment and to prevent thermal decomposition of the final product.

Examples of the antioxidant include liposoluble antioxidants such as propyl gallate, ethyl protocatechuate, butylated hydroxycyanthol (BHT), butylated hydroxytoluene (BHA), tertiary butyl hydroquinone (TGHQ) Propyl gallate and oxystearin. Examples of the water-soluble antioxidant include erythorbic acid, ascorbyl palmitate and disodium ethylene diamine tetraacetate (EDTA 2Na) , So the format is not limited.

The antioxidant is included in an amount of 0.1 to 0.2% by weight. When the content is less than 0.1% by weight, the physical properties of the composition deteriorate and the performance of the finished product deteriorates over a long period of use. When the content exceeds 0.2% by weight, the production cost of the product increases, Blooming) problems. And preferably 0.18 to 0.20% by weight.

(F) Inorganic filler

The inorganic filler is used to reduce the role of the filler, maintain the shape of the molded product, and reduce the cost of the material.

Examples of the inorganic filler include silica, alumina, zinc oxide, zirconium oxide, aluminosilicate, titanium oxide, cerium oxide, hafnium oxide, niobium pentoxide, tantalum pentoxide, indium oxide, tin oxide, indium tin oxide, Calcium carbonate, barium sulfate, or magnesium oxide may be used, but the present invention is not limited thereto.

The inorganic filler may be fibrous, granular, needle-shaped, sheet-like, or thin-film, and is preferably particulate.

It is preferable that the inorganic filler has a binding particle diameter of 1 nm to 100 nm. In this range, the inorganic filler is uniformly dispersed in the resin, so that the desired effect can be properly ensured.

The inorganic filler is contained in an amount of 5.0 to 6.0% by weight of the whole composition. When the content is less than 5.0 wt%, the filler does not act as a filler. When the content is more than 6.0 wt%, the blow molding operation becomes difficult due to a hardness increase and a material flow problem. Preferably 5.00 to 5.20% by weight.

(G) Other additives

In an embodiment, the composition may further comprise at least one additive selected from the group consisting of light stabilizers, crosslinking aids, pigments, lubricants and waxes.

For the production of the thermoplastic elastomer composition of the present invention, the light stabilizer, the crosslinking assistant, the pigment, the lubricant and the wax may be used. Preferably, the additive is a polypropylene Based wax, but it is not particularly limited thereto.

The amount of the additive used in the composition of the present invention is preferably 0.1 to 0.2% by weight, and more preferably 0.10 to 0.12% by weight. It is desirable to compensate for the slip property, the abrasion resistance, the surface of the blow molded article, the glossiness, and other properties such as the bondability between the resins necessary for producing the thermoplastic elastomer composition of the present invention in the above content range.

Automotive parts

An automotive part, which is another aspect of the present invention, is produced by molding the thermoplastic elastomer composition.

The molding method may be blow molding, vacuum molding, injection molding, extrusion molding, or the like, preferably blow molding.

The thermoplastic elastomer composition of the present invention can provide a molded article by performing blow molding. Such a molded article can be used for various industrial materials and parts thereof, an air suction device of an automobile, an exhaust device, . ≪ / RTI > In the present invention, it may be preferably an automotive gear box bellows.

A common vehicle gearbox seals the interior of the gearbox with a bellows to prevent lubrication and corrosion. Therefore, when the outside temperature of the vehicle or the internal temperature of the steering gear box rises, the pressure inside the sealed gear box rises and deformation of the bellows, which is vulnerable to pressure change, occurs.

The role of the gear box bellows in an automobile is important because the steering gearbox can cause interference between internal components and the bellows if deformation occurs in the bellows and can cause component failure or seizure.

The thermoplastic elastomer composition according to the present invention is manufactured for a gearbox bellows used in a steering system for a vehicle, and the manufacturing method is not particularly limited, but preferably it can be manufactured by a blow molding method.

In a specific example, the blow molding is performed by injecting a composition material, air blowing the injected material, opening and closing the air-blown material, cooling the mold-opened material, It can be molded for 25 to 35 seconds by demolding the cooled material.

The manufacturing process of the gear box bellows may be a material injection, an air blow, a mold opening / closing, a cooling, and a demoulding process when a blow molding process is performed using a thermoplastic elastomer material. Can complete all processes within 25 seconds to 35 seconds, preferably within 30 seconds.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Example

For the production of the thermoplastic elastomer composition of the present invention, specific specifications of the components used in the following examples and comparative examples are as follows.

(1) KEP-2480 (manufactured by Kumho Polychem Co., Ltd.) was used as ethylene propylene diene rubber (EPDM).

(2) 5014L HPT-1 and BP2000 (Korea Epoxy Resin Co., Ltd.) were used as the polypropylene (PP) resin.

(3) KL-900B (Sejing Chemical Co., Ltd.) was used as a paraffin oil.

(4) PEROXAN HX50PS (Taehwa Corporation) was used as a peroxide crosslinking agent.

(5) ZnO (Hanil Zinc Co., Ltd.) was used as an antioxidant.

(6) S-1000 (Rexem) was used as an inorganic filler.

Example 1

A thermoplastic elastomer composition was prepared by mixing ethylene propylene diene rubber (EPDM), polypropylene (PP), paraffin oil, peroxide crosslinking agent, antioxidant, inorganic filler and other additives as shown in Table 1 below.

Thereafter, the material of the thermoplastic elastomer composition is injected, the injected material is air-blown, the air-blown material is opened and closed, the cooled material is cooled, The gear box bellows was molded.

Examples 2 to 3

A thermoplastic elastomer paste was produced in the same manner as in Example 1, except that wax was used as the other additive, and the gear box bellows of an automobile was molded.

Reference example

A thermoplastic elastomer paste was produced in the same manner as in Example 1, except that wax was used as the other commercially available product at the composition and magnification ratio shown in Table 1 below, and then the gear box bellows of an automobile was molded.

Example 1 Example 2 Example 3 Reference example Ethylene propylene
Diene rubber (EPDM) 24.8 25.7 24.5 19 Polypropylene (PP) 44.7 42.2 44.6 47.5 Paraffin oil 24.9 25.7 24.5 28.4 Phenolic resin
Cross-linking agent - - - - Peroxide
Cross-linking agent 0.4 0.3 0.35 0.2 Antioxidant 0.1 0.2 0.15 0.1 Inorganic filler 5.0 5.8 5.8 4.7 Other additives 0.1 0.1 0.1 0.1

(Unit: wt%)

Comparative Examples 1 to 10

A thermoplastic elastomer paste was produced in the same manner as in Example 1 except that wax was used as the other additives, and the gear box bellows of an automobile was molded.

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Ethylene propylene
Diene rubber (EPDM) 50 45 55 50 45 Poly
Propylene (PP) - 35 35 30 33 Paraffin oil 30.4 - 5 10.4 7.7 Phenolic resin
Cross-linking agent - - - - - Peroxide
Cross-linking agent 15 11 - 3 0.5 Antioxidant 3.5 0.4 1.4 One 8.5 Inorganic filler One 8.5 3.5 5.5 5.2 Other additives 0.1 0.1 0.1 0.1 0.1

(Unit: wt%)

Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Ethylene propylene
Diene rubber (EPDM) 35 41 32 30 40 Poly
Propylene (PP) 30 35 31 40 37 Paraffin oil 15.1 10.5 17 15 15.4 Phenolic resin
Cross-linking agent - - - - 1.5 Peroxide
Cross-linking agent 10.5 5 11 10 - Antioxidant 3.5 5.4 0.5 1.4 2.5 Inorganic filler 5.8 3 8.4 3.5 3.5 Other additives 0.1 0.1 0.1 0.1 0.1

(Unit: wt%)

Experimental Example

The thermoplastic elastomer composition prepared in Examples 1 to 3, Reference Example, and Comparative Examples 1 to 10 and the basic materials properties, heat resistance, oil resistance, compression set length and ozone resistance of the gear box bellows formed by molding the same And the results are shown in Tables 4 to 5 below.

Each physical property measurement method is specifically described as follows.

How to measure property

- Basic properties

(1) Hardness (shore D): Hardness was measured by an ISO 868 method using a spring type hardness device (ASKER).

(2) Tensile strength (kgf / cm 2): The tensile strength was measured by an ISO 37 method using a UTM apparatus (INSTRON).

(3) Elongation at break (%): The elongation at break was measured by an ISO 37 method using a UTM apparatus (INSTRON).

(4) 100% modulus (kgf / cm 2): 100% modulus was measured by an ISO 37 method using a UTM device (INSTRON).

(5) Tear strength (kgf / cm): The tear strength was measured by an ISO 34-1 method using a UTM apparatus (INSTRON).

- Heat resistance property

In order to evaluate the heat resistance property, the change in physical properties after 168 hours at 125 캜 was measured, and it is as follows.

(1) Change in hardness (shore D): In order to understand the hardness change as heat resistance property, it was measured by ISO 888 method using a spring type hardness device (ASKER).

(2) Tensile strength change rate (%): In order to determine the rate of change in tensile strength as a heat resistance property, it was measured by an ISO 888 method using a UTM apparatus (INSTRON).

(3) Elongation rate (%): In order to determine the rate of elongation as a heat resistance property, it was measured by an ISO 888 method using a UTM apparatus (INSTRON).

(4) 100% modulus change rate (%): In order to determine the 100% modulus change rate as heat resistance property, it was measured by an ISO 888 method using a UTM device (INSTRON).

- oil resistance

In order to evaluate the oil resistance, the change in physical properties after ASTM NO.3 OIL deposition at 125 DEG C for 70 hours was measured as follows.

(1) Hardness change (shore D): In order to understand hardness change as oil resistance, it was measured by ISO 1817 method using a spring type hardness device (ASKER).

(2) Tensile strength change ratio (%): In order to determine the rate of change in tensile strength as the oil resistance, it was measured by the ISO 1817 method using a UTM apparatus (INSTRON).

(3) Elongation Change Rate (%): The ISO 1817 method was used to measure the rate of elongation as oil resistance, using a UTM apparatus (INSTRON).

(4) 100% modulus change rate (%): The ISO 1817 method was used to measure the 100% modulus change rate as oil resistance, using a UTM device (INSTRON).

(5) Tear strength change ratio (%): In order to determine the rate of change in tear strength due to oil resistance, it was measured by the ISO 1817 method using a UTM apparatus (INSTRON).

(6) Optimum rate of change (%): In order to determine the optimum rate of change as oil resistance, it was measured by the ISO 1817 method using a precision electronic balance device (MIRAGE).

- Other

(1) Compression Permanent Rowing Rate (%): Compression Permanent Drowsiness Rate was measured by the ISO 815 method using a heat aging CHAMBER device (Daekyung Engineering Co., Ltd.).

(2) Ozone Resistance: The ozone resistance was measured by the ISO 1431-1 method using an ozone tester (Daikyoung Engineering Co., Ltd.). After 72 hours at the ozone concentration of 100 ppm and 40 ° C, the finished product was checked for external cracks.

division Example 1 Example 2 Example 3 Reference example Comparative Example 1 Comparative Example 2 Comparative Example 3 basic
Properties Hardness (Shore D) 43 44 43.5 41 40 47 46 Tensile strength (kgf / cm2) 185 180 182 175 159 198 163 Elongation at break (%) 630 620 625 580 550 680 570 100% modulus (kgf / cm2) 89 91 90 84 83 95 85 Tear strength (kgf / cm) 73 75 73.5 70 67 78 69 Heat resistance
Properties Hardness change (Shore D) 3 3 3 3 4 2 5 Tensile strength change rate (%) -4 -4 -4.2 -6 -7 -4 -7.5 Elongation rate (%) -19 -20 -19.5 -27 -24 -17 -25 100% Modulus change rate (%) 15 15 15 21 24 18 28 Oil
Properties Hardness change (Shore D) -11 -12 -12 -15 -15 -10 -15 Tensile strength change rate (%) -18 -20 -19 -22 -28 -17 -29 Elongation rate (%) -35 -37 -37.5 -40 -43 -34 -45 100% Modulus change rate (%) -9 -10 -9.5 -11 -15 -8 -13 Tear Strength Change Rate (%) -41 -42 -41 -46 -50 -39 -50 Optimum change rate (%) 49 50 49.5 53 59 48 57 Compression Permanent Quadrature (%) 77 80 79 81 83 75 85 Ozone resistance ◎ ◎ ◎ ◎ ◎ ◎ ◎

division Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 basic
Properties Hardness (Shore D) 45 47 48 44 46 47 46 Tensile strength (kgf / cm2) 162 170 197 153 164 192 168 Elongation at break (%) 565 592 605 595 578 583 560 100% modulus (kgf / cm2) 83 95 85 83 95 85 83 Tear strength (kgf / cm) 67 78 69 67 78 69 67 Heat resistance
Properties Hardness change (Shore D) 5 2 4 4 5 2 6 Tensile strength change rate (%) -6 -7 -6 -5 -8 -7.5 -7 Elongation rate (%) -23 -15 -23 -22 -19 -24 -21 100% Modulus change rate (%) 22 19 26 23 19 27 23 of mine
U
water
castle Hardness change (Shore D) -13 -11 -16 -15 -12 -16 -14 Tensile strength change rate (%) -30 -19 -28 -27 -19 -28 -25 Elongation rate (%) -45 -32 -47 -48 -37 -46 -41 100% Modulus change rate (%) -14 -10 -15 -17 -10 -14 -16 Tear Strength Change Rate (%) -51 -45 -48 -52 -38 -49 -52 Optimum change rate (%) 58 47 58 57 51 52 48 Compression Permanent Quadrature (%) 85 72 86 87 76 81 80 Ozone resistance ◎ ◎ ◎ ◎ ◎ ◎ ◎

Physical property measurement result

As a result of measurement of the physical properties of the gear box bellows according to the present invention, when the gear box bellows used in the steering system for a vehicle is manufactured using the heat distortion-enhancing thermoplastic elastomer composition of the present invention as shown in Tables 4 to 5, It is excellent in basic property, heat resistance, oil resistance, ozone resistance and compression durability, and bending phenomenon of gear box due to heat history after blow molding is improved. It is possible to secure superior rigidity and long-term heat resistance.

As described above, the thermoplastic elastomer composition according to the present invention and the gear box bellows for automobile manufactured using the same can minimize deformation due to thermal history during operation, have excellent rigidity and long-term heat resistance, and can be recycled Burrs and defective products generated during the production of the product can be crushed and recycled in real time by a method such as injection molding or vacuum molding to provide environmental protection and cost saving (see Tables 4 to 5 above) ).

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. This is possible.

Therefore, the scope of the present invention should not be limited by the described embodiments, but should be determined by the scope of the appended claims as well as the appended claims.

Claims (8)

24.5 to 26.0% by weight of ethylene propylene diene rubber (EPDM);
42.0 to 45.0% by weight of polypropylene (PP);
24.0 to 26.0% by weight of paraffin oil;
From 0.3 to 0.4% by weight of a peroxide crosslinking agent;
0.1 to 0.2% by weight of an antioxidant; And
5.0 to 6.0% by weight of an inorganic filler;
And a thermoplastic elastomer composition.
The method according to claim 1,
(B1) a homo-polypropylene having a melt flow index (230 DEG C, 2.16 kg) of more than 0 and less than or equal to 2.0 g / 10 min; And
(b2) a block copolymer having a melt flow index (Melt Flow Index, 230 DEG C, 2.16 kg) of not less than 0 g / 10 min and not more than 0.5 g / 10 min.
3. The method of claim 2,
Wherein the weight ratio of (b1) homopolypropylene to (b2) block copolymer is from 1.5: 1 to 2: 1.
The method according to claim 1,
Wherein the paraffin oil has a kinematic viscosity at 40 占 폚 of 170 cSt or more.
The method according to claim 1,
Wherein the composition further comprises at least one additive selected from the group consisting of a light stabilizer, a crosslinking assistant, a pigment, a lubricant, and a wax.
An automotive part molded from the thermoplastic elastomer composition of any one of claims 1 to 5.
The method according to claim 6,
Characterized in that said automotive component is an automotive gear box bellows.
The method according to claim 6,
Wherein the molding is a blow molding.

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