KR20210065506A - Thermoplastic elastomer composition and transparent member - Google Patents

Abstract

The present invention relates to a thermoplastic elastomer composition, which comprises: a first SEBS block copolymer resin having a weight average molecular weight of 230,000 g/mol or more and 400,000 g/mol or less; a second SEBS block copolymer resin having a weight average molecular weight of 100,000 g/mol or more and 200,000 g/mol or less; and a random polypropylene resin, wherein a weight ratio of the first SEBS block copolymer resin and the second SEBS block copolymer resin is 5 : 95 to 30 : 70, and to a light-transmitting member comprising a light-transmitting layer prepared using the same. An objective of the present invention is to provide the thermoplastic elastomer composition, capable of manufacturing a light transmitting layer having high compatibility with an olefinic member and improved light transmittance and scratch resistance.

Description

A thermoplastic elastomer composition and a light-transmitting member {THERMOPLASTIC ELASTOMER COMPOSITION AND TRANSPARENT MEMBER}

The present invention relates to a light-transmitting member comprising a thermoplastic elastomer composition and a light-transmitting layer manufactured using the same.

Automobile interior parts provide convenience to passengers, and the appearance and feel of interior parts are important factors influencing the emotional quality of automobiles. Such automobile interior parts include a handle, an instrument panel, a door trim, and a head liner. These interior parts are becoming an important factor in determining the emotional quality of the interior of a vehicle.

In recent years, as luxury and individualization of automobiles are required, the appearance of interior parts that determine the aesthetics of the interior of the automobile is required to be upgraded. In addition, lighting lamps, instrument panel, and switch lights are provided inside the vehicle for internal occupants when driving at night or in dark places, and instrument panel and door trims are provided to create a subtle atmosphere inside the car to satisfy the sensibility of the occupants. In some cases, mood lighting and the like are additionally provided on the back. Automotive interior parts requiring such light transmittance may be manufactured by arranging a light source inside an opaque injection-molded product, painting the surface of the injection-molded product, or surface treatment using a film. However, conventional automotive interior parts requiring light transmission have poor compatibility with olefin-based members used in automotive interior parts, and poor scratch resistance, and mesh and foam between the olefin-based member and the light-transmitting layer. And adhesives are provided, and there is a problem that recycling is impossible.

Accordingly, it is necessary to study the light transmitting layer that can be provided in the olefin-based member without a separate intermediate member to enable recycling of defective products generated during the manufacturing process.

Republic of Korea Public Publication: No. 10-2019-0061134

An object of the present invention is to provide a light-transmitting member including a thermoplastic elastomer composition and a light-transmitting layer manufactured using the same. Specifically, an object of the present invention is to provide a thermoplastic elastomer composition capable of preparing a light transmitting layer having high compatibility with an olefinic member and improved light transmitting properties and scratch resistance. Another object of the present invention is to provide a light-transmitting member having visibility and aesthetics suitable for automobile interior parts.

An exemplary embodiment of the present invention, a first SEBS block copolymer resin having a weight average molecular weight of 230,000 g/mol or more and 400,000 g/mol or less; A second SEBS block copolymer resin having a weight average molecular weight of 100,000 g/mol or more and 200,000 g/mol or less; and a random polypropylene resin, wherein the weight ratio of the first SEBS block copolymer resin and the second SEBS block copolymer resin is 5:95 to 30:70, and provides a thermoplastic elastomer composition.

Another embodiment of the present invention, an opaque substrate; And to provide a light-transmitting member comprising a light-transmitting layer prepared using the thermoplastic elastomer composition on at least one surface of the opaque substrate.

The thermoplastic elastomer composition according to an exemplary embodiment of the present invention can prepare a light transmitting layer having high light transmittance and scratch resistance. In addition, the thermoplastic elastomer composition according to an exemplary embodiment of the present invention can manufacture a light-transmitting member having a light-transmitting layer on the olefin-based member without a separate adhesive and member through double injection with the olefin-based resin composition. The light-transmitting member according to the present invention is provided with a light-transmitting layer without a separate adhesive, so that it can be easily recycled when a defect occurs in the manufacturing process.

1 shows a light-transmitting layer sample prepared using the thermoplastic elastomer composition according to Example 1. Referring to FIG.
FIG. 2 shows a light-transmitting door trim provided with a light-transmitting layer manufactured using the thermoplastic elastomer composition according to Example 1. Referring to FIG.

In the present specification, when a member is said to be located “on” another member, this includes not only a case in which a member is in contact with another member but also a case in which another member exists between the two members.

In the present specification, when a part "includes" a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise stated.

In the present specification, the unit “parts by weight” may mean a ratio of weight between each component.

In the present specification, the weight average molecular weight (g/mol) may be a value converted to polystyrene measured by gel permeation chromatography (GPC).

The present inventors have discovered that conventional light-transmitting automotive interior parts have problems with low scratch resistance and/or low light transmission properties. In addition, it was confirmed that the existing light-transmitting layer is attached to the olefin-based interior parts through other intermediate members such as adhesives and meshes, and thus cannot be recycled when a defect occurs. Accordingly, as a result of continuing research on a composition for a light-transmitting layer having excellent compatibility with olefin-based interior parts, double injection with an olefin-based resin composition, and excellent light transmittance and scratch resistance, the present invention was completed. .

Hereinafter, the present invention will be described in detail.

An exemplary embodiment of the present invention, a first SEBS block copolymer resin having a weight average molecular weight of 230,000 g/mol or more and 400,000 g/mol or less; A second SEBS block copolymer resin having a weight average molecular weight of 100,000 g/mol or more and 200,000 g/mol or less; and a random polypropylene resin, wherein the weight ratio of the first SEBS block copolymer resin and the second SEBS block copolymer resin is 5:95 to 30:70, and provides a thermoplastic elastomer composition.

first and second SEBS (styrene-ethylene- butylene -styrene) block copolymer resin

According to an exemplary embodiment of the present invention, the SEBS block copolymer resin may have a saturated olefin structure composed of polyethylene and polybutylene through a process of undergoing a complete catalytic hydrogenation reaction on the polybutadiene block of SBS, which is a precursor. The SEBS block copolymer is a copolymer including an aromatic vinyl compound and a conjugated diene-based compound, and may impart ductility to the thermoplastic elastomer composition. Specifically, the aromatic vinyl compound may be a hard segment, and contribute to preventing thermoplastic deformation and imparting physical properties such as a crosslinked product under certain conditions. In addition, the conjugated diene-based compound may be a soft segment, and contributes to imparting ductility properties such as rubber.

The thermoplastic elastomer composition according to the present invention can improve the injectability and melt index of the thermoplastic elastomer composition by applying SEBS block copolymer resins having different weight average molecular weights, and can also improve hardness and light transmittance. Specifically, the first SEBS block copolymer resin may be a high molecular weight SEBS block copolymer having a weight average molecular weight of 230,000 g/mol or more and 400,000 g/mol or less, more specifically 250,000 g/mol or more and 300,000 g/mol or less. The first SEBS block copolymer resin may improve scratch resistance by improving the hardness of the light transmitting layer prepared by using the thermoplastic elastomer composition, and may be applied together with random polypropylene to implement high light transmittance. In addition, the second SEBS block copolymer resin may be a low molecular weight SEBS block copolymer resin having a weight average molecular weight of 100,000 g/mol or more and 200,000 g/mol or less, more specifically 120,000 g/mol or more and 180,000 g/mol or less. The second SEBS block copolymer resin may improve the flowability of the thermoplastic elastomer composition to increase the injection property.

According to an exemplary embodiment of the present invention, the weight ratio of the first SEBS block copolymer resin and the second SEBS block copolymer resin may be 5:95 to 30:70, more specifically 15:85 to 25:75. . Specifically, when the weight ratio of the first SEBS block copolymer resin and the second SEBS block copolymer resin is within the above range, the thermoplastic elastomer composition may have high light transmittance, hardness and high injection property. When the content of the first SEBS block copolymer resin exceeds 25 parts by weight based on the total SEBS block copolymer resin, the flowability of the composition may be lowered and injection may be difficult. In addition, when the content of the 1 SEBS block copolymer resin is less than 5 parts by weight based on the total SEBS block copolymer resin, the hardness of the prepared light-transmitting layer is lowered, which may affect product performance.

According to an exemplary embodiment of the present invention, the total content of the first and second SEBS block copolymers is 30 parts by weight or more and 70 parts by weight or less, or 40 parts by weight or more and 60 parts by weight or less based on 100 parts by weight of the thermoplastic elastomer composition. can When the total content of the first and second SEBS block copolymers is within the above range, by imparting appropriate elasticity to the prepared light transmitting layer, scratch resistance can be further improved, and impact resistance can be secured.

random polypropylene resin (Random PP)

According to an exemplary embodiment of the present invention, the random polypropylene resin may be included to further improve the light transmittance of the thermoplastic elastomer.

The random polypropylene resin according to the present invention may be an ethylene-propylene random copolymer. The random polypropylene resin is a crystalline copolymer containing propylene as a main component, propylene and ethylene are simultaneously added to a polymerization reactor, triethyl aluminum, a Dicer catalyst, and a silane-based electron donor are injected, and then the reaction temperature is 65° C. to 75° C. ℃, under 32 K/G to 35 K/G atmosphere, it can be prepared by bulk polymerization of slurry, and the melt index can be controlled by hydrogen.

According to an exemplary embodiment of the present invention, the ethylene content of the random polypropylene may be 1 part by weight or more and 6 parts by weight or less, specifically 2 parts by weight or more and 4 parts by weight or less, based on 100 parts by weight of the random polypropylene resin.

According to an exemplary embodiment of the present invention, the melt index (2.16 kg, 230 ℃) of the random polypropylene resin may be 20 g/10min or more and 40 g/10min or less. When the melt index of the random polypropylene resin is within the above range, the flowability of the thermoplastic elastomer composition may be maintained so as not to become excessively high.

According to an exemplary embodiment of the present invention, the weight average molecular weight of the random polypropylene resin may be 300,000 g/mol or more and 400,000 g/mol or less. When the weight average molecular weight of the random polypropylene resin is within the above range, high transparency and high strength of the light-transmitting layer prepared using the thermoplastic elastomer composition can be realized.

According to an exemplary embodiment of the present invention, with respect to 100 parts by weight of the total weight of the first SEBS block copolymer resin and the second SEBS block copolymer resin, the content of the random polypropylene resin may be 10 parts by weight or more and 30 parts by weight or less. have. Within the content range of the random polypropylene resin, the thermoplastic elastomer composition may have high double injection property and light transmittance, and high mechanical properties may be implemented.

additive

According to an exemplary embodiment of the present invention, the thermoplastic elastomer composition may further include an additive selected from the group consisting of a non-aromatic oil, an inorganic filler, a heat stabilizer, an antioxidant, and a slip agent. However, the present invention is not limited thereto, and may further include additives commonly used in the art.

According to an exemplary embodiment of the present invention, the thermoplastic elastomer composition may further include a non-aromatic oil. The thermoplastic elastomer composition according to the present invention may further include a non-aromatic oil to improve hardness, moldability, and oil resistance, which are directly related to the feel of the thermoplastic elastomer. In addition, the paraffin oil may serve to appropriately control the flowability of the thermoplastic elastomer composition, thereby ensuring double injection property.

According to an exemplary embodiment of the present invention, the non-aromatic oil may include paraffin oil. The paraffin oil may have a kinematic viscosity of 90 cSt or more, or 90 cSt or more and 180 cSt or less, or 100 or more and 150 cSt or less at 40°C.

According to an exemplary embodiment of the present invention, the content of the non-aromatic oil may be 20 parts by weight or more and 40 parts by weight or less based on 100 parts by weight of the thermoplastic elastomer composition. If the content of the non-aromatic oil is less than the above range, the flowability during injection molding is poor, which may cause molding defects and poor operation, and if the content of the non-aromatic oil exceeds the above range, the flowability increases excessively, During injection molding, there is a problem that a shape defect and a long cooling time are required.

According to an exemplary embodiment of the present invention, the inorganic filler may include at least one selected from the group consisting of talc, calcium carbonate, clay, nanoclay, and kaolin. The inorganic filler may be included to improve physical properties and molding processability of the thermoplastic elastomer composition, and the content thereof may be 0.5 parts by weight or more and 20 parts by weight or less based on 100 parts by weight of the thermoplastic elastomer composition. Specifically, the content of the inorganic filler may be 5 parts by weight or more and 15 parts by weight or less.

According to an exemplary embodiment of the present invention, the melt index (2.16 kg, 230 ℃) of the thermoplastic elastomer composition may be 45 g/10 min or more and 60 g/10 min or less. Specifically, when the melt index of the thermoplastic elastomer composition is within the above range, injection property is easy, and it may be possible to manufacture the light-transmitting member through double extrusion with the olefin-based resin composition.

Another embodiment of the present invention, an opaque substrate; and a light-transmitting layer prepared using the thermoplastic elastomer composition on at least one surface of the opaque substrate.

According to an exemplary embodiment of the present invention, the light-transmitting member may be a double injection product of the olefin-based resin composition as the material of the opaque substrate and the thermoplastic elastomer composition as the material of the light-transmitting layer. As described above, since the thermoplastic elastomer composition has excellent injection property and excellent compatibility with the olefin-based resin composition, through double injection with the olefin-based resin composition, an opaque substrate without a separate adhesive and/or intermediate member A light-transmitting member having a light-transmitting layer thereon may be manufactured. Specifically, the light-transmitting member may be manufactured using a manufacturing method comprising the step of double-injecting the olefin-based resin composition as the material of the opaque substrate and the thermoplastic elastomer composition as the material of the light-transmitting layer. The double injection method in the present specification may be applied without limitation to the double injection method generally known in the art.

According to an exemplary embodiment of the present invention, the opaque substrate may be a cured product of the olefin-based resin composition. The olefin-based resin composition may include at least one selected from the group consisting of a thermoplastic resin, a thermoplastic elastomer, and foam.

According to an exemplary embodiment of the present invention, the transmittance of the light-transmitting layer may be at least 75% or more. The transmittance may be measured using a Haze meter or a UV transmittance meter.

According to an exemplary embodiment of the present invention, the light-transmitting member may be an automobile interior component. Specifically, the automobile interior part may be a handle, a garnish, an instrument panel, a door trim, a console, or a head liner.

Hereinafter, examples will be given to describe the present invention in detail. However, the embodiments according to the present invention may be modified in various other forms, and the scope of the present invention is not to be construed as being limited to the embodiments described below. The embodiments of the present specification are provided to more completely explain the present invention to those of ordinary skill in the art.

Example and comparative example

After removing foreign substances by filtering the raw materials in Table 1 below, the composition as shown in Table 1 below was mixed to prepare a thermoplastic elastomer composition using an extruder.

Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 1st SEBS
(parts by weight) 10 35 25 15 25 2nd SEBS
(parts by weight) 40 15 25 35 25 paraffin oil
(parts by weight) 30 30 30 30 30 talc
(parts by weight) 10 10 10 10 10 Random-PP
(parts by weight) 10 10 Block-PP
(parts by weight) 10 10 10 - 1st SEBS: TSRC, TAIPOL SEBS, Mw: 280,000 g/mol
- Second SEBS: TSRC, TAIPOL SEBS, Mw: 150,000 g/mol
- Paraffin oil: Michang Oil Industry Co., Ltd., W-1900H (Kinematic viscosity (@ 40℃137 cSt)
- Talc: Kotsu Corporation, KCM-6300, (number average particle diameter: 4.0 ㎛)
- Random-PP: J-580S, (MI(ASTM D 1238, 230℃ 2.16kg load): 35 g/10min)
- Block-PP: JM-370, (MI(ASTM D 1238, 230℃ 2.16kg load): 35 g/10min)

The results of evaluation of physical properties for the melt index (MI), hardness (Shore A), light transmittance (Haze) and injection property of the thermoplastic elastomer compositions according to Example 1 and Comparative Examples 1 to 4 prepared above are shown in Table 2 below. .

Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 MI (g/10min)
(15Kg, 230℃) 50 41 43 45 44 Hardness
(shore A) 45 50 48 47 46 transmittance
(Haze, %) 78 65 65 68 78 injection
(Visual evaluation) ○ △ △ ○ △

<Method of measuring physical properties>

- Melt flow index (MI): In accordance with ISO 1133, the weight of the resin that flowed at 230 ℃ using a 15 kg weight was measured at the specified time.

- Hardness: Using Shore hardness tester A Type, it was evaluated according to the standard of ISO 868. For the thickness of the specimen, the value of 15 seconds after the start of measurement was used by overlapping 3 2T injection specimens.

- Transmittance (Haze, %): Based on ASTM D1003, transparency (Haze) of the 2T-thick injection film specimen was measured.

- Injection property: When the manufactured thermoplastic elastomer composition is double-injected with the olefin-based resin composition to produce joint parts for automobiles, and double injection is not possible ×, when the double injection molding product has poor adhesion between different materials or has poor appearance. The case was evaluated as △, if there was no problem in adhesion and appearance between different materials of the double injection molded product as ○.

<Evaluation>

Referring to the results according to Examples and Comparative Examples, as the content of the second SEBS block copolymer resin having a low molecular weight increased, the melt index of the thermosetting elastomer composition increased, and it was confirmed that the injection property was improved. In addition, as the content of the first SEBS block copolymer resin having a high molecular weight increased, the melt index of the thermosetting elastomer composition decreased, and it was confirmed that the injection property decreased. Furthermore, referring to Comparative Examples 2 and 4, it can be seen that the light transmittance is greatly improved when the random polypropylene resin is applied as compared to the case where the block polypropylene resin is applied.

In addition, in order to ensure compatibility for double injection with the thermoplastic olefin-based elastomer used for automobile interior parts, it may be desirable to have a shore hardness of 45 or less and a melt index of 50 g/10 min or more. In addition, it is preferable to have a light transmittance of 75% or more in order to be able to transmit the light inside the automobile interior parts.

In Comparative Examples 1, 2 and 4, the content of the first SEBS block copolymer resin having a high molecular weight was too high, indicating a low melt index, thereby confirming that the injection property was poor. could be seen to indicate. In addition, in the case of Comparative Example 3, although injection properties were secured, it was confirmed that the block polypropylene resin exhibited low transmittance due to application of the block polypropylene resin. On the other hand, in the case of Example 1, it was confirmed that all of the injection property, light transmittance, and Shore A hardness according to the melt index suitable for use as a light transmitting layer for automotive interior parts were satisfied.

1 shows a light-transmitting layer sample prepared using the thermoplastic elastomer composition according to Example 1. Referring to FIG. FIG. 2 shows a light-transmitting door trim provided with a light-transmitting layer manufactured using the thermoplastic elastomer composition according to Example 1. Referring to FIG. As can be seen in FIGS. 1 and 2 , the light transmitting layer according to Example 1 exhibits high light transmittance, and thus it can be confirmed that it is suitable for application as a light transmitting layer for automotive interior parts.

Claims (8)

A first SEBS block copolymer resin having a weight average molecular weight of 230,000 g/mol or more and 400,000 g/mol or less; A second SEBS block copolymer resin having a weight average molecular weight of 100,000 g/mol or more and 200,000 g/mol or less; and random polypropylene resin;
The weight ratio of the first SEBS block copolymer resin and the second SEBS block copolymer resin is 5:95 to 30:70, the thermoplastic elastomer composition. The method according to claim 1,
The melt index (2.16 kg, 230 ℃) of the random polypropylene resin is 20 g/10 min or more and 40 g/10 min or less, and the weight average molecular weight of the random polypropylene resin is 300,000 g/mol or more and 400,000 g/mol or less. A thermoplastic elastomer composition, characterized in that. The method according to claim 1,
The thermoplastic elastomer composition has a melt index (2.16 kg, 230° C.) of 45 g/10 min or more and 70 g/10 min or less. The method according to claim 1,
Based on 100 parts by weight of the total weight of the first SEBS block copolymer resin and the second SEBS block copolymer resin, the content of the random polypropylene resin is 10 parts by weight or more and 30 parts by weight or less, The thermoplastic elastomer composition. The method according to claim 1,
The thermoplastic elastomer composition further comprises an additive selected from the group consisting of non-aromatic oils, inorganic fillers, heat stabilizers, antioxidants and slip agents. opaque substrate; and a light transmitting layer prepared using the thermoplastic elastomer composition according to claim 1 on at least one surface of the opaque substrate. 7. The method of claim 6,
The light-transmitting member is a double injection product of the olefin-based resin composition as the material of the opaque substrate and the thermoplastic elastomer composition as the material of the light-transmitting layer. 7. The method of claim 6,
The light-transmitting member is an automobile interior part.

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