KR101431906B1 - Polypropylene resin composition with low gloss - Google Patents

Abstract

The present invention provides a low-gloss polypropylene resin composition, more specifically, an ethylene propylene block copolymer resin comprising a homopolypropylene polymer portion and an ethylene-propylene copolymer portion, wherein the ethylene-propylene block copolymer resin is 30 Wherein the ethylene-propylene copolymer has an intrinsic viscosity of from 3.0 to 8.0 dL / g and a melt viscosity of from 300,000 to 800,000 daltons / g and a melt index of 110 g / 10 min (230 DEG C, 2.16 Kg) and an ethylene content of 10 to 25.0 mol% Da. ≪ / RTI > The present invention can provide a low-gloss polypropylene resin composition suitable for plastic molded articles requiring low gloss characteristics.

Description

TECHNICAL FIELD The present invention relates to a low-gloss polypropylene resin composition,

The present invention relates to a low-gloss polypropylene resin composition.

Plastic injection molded articles using polyolefins are used as high-grade plastic materials for automobiles or households. In the past, such high-grade plastic materials tended to prefer high-gloss products, but in recent years, there has been an increasing demand for high-quality products of matte materials. In particular, in the case of automobile plastic interior materials, There is a growing demand for materials that exhibit low-gloss characteristics, since light that interferes with the driver's vision may seriously impair safety during driving. Methods of lowering the gloss of a product made of such a polyolefin resin include 1) adding an inorganic substance (talc, silica, etc.), 2) mixing a plastic rubber component, 3) applying a plastic product surface with a low-gloss material, 4) , 5) modification of the resin composition in the reaction vessel, and the like, and mixing the polypropylene resin with other additives. However, when a large amount of inorganic materials such as talc is added, the specific gravity of the resin increases, which is not preferable for automobile plastic materials in which low specific gravity products are preferred. In the case of using a large amount of polyolefin or fluororesin rubber, The bending stiffness may be lowered than the impact characteristics. As another method of lowering the gloss of a product made of a polyolefin resin, there is a method of lowering the gloss of the polypropylene copolymer resin composition produced in the reaction vessel. For example, a polypropylene-polyethylene polymer containing a polyolefin elastomer (rubber) is produced in a reaction vessel. However, in the case of the polypropylene-polyethylene copolymer resin produced in this reactor, the amount of the polyolefin rubber should be 30% or more to provide a satisfactory low-gloss property, and the bending stiffness is very low as compared with the impact characteristic.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a polypropylene resin composition which is excellent in rigidity and impact properties and can exhibit low surface gloss and is applicable as a low-gloss high-grade plastic product for automobiles or household appliances.

According to an aspect of the present invention,

Propylene block copolymer resin comprising a homopolypropylene polymer portion and an ethylene-propylene copolymer portion, wherein the ethylene-propylene block copolymer resin has a melting point of 30 to 110 g / 10 min (230 DEG C, 2.16 Kg) Indices; And an ethylene content of 10.0 to 25.0 mol%, wherein the ethylene-propylene copolymer has an intrinsic viscosity of 3.0 to 8.0 dL / g and a weight average molecular weight of 300,000 to 800,000 Da.

Wherein the polypropylene resin composition has a surface glossiness (Gloss, 60 ^o , colorless flat panel injection test piece) of 65% or less, an arithmetic average surface roughness (Ra) value of 60 to 160 nm, and a ten-point average surface roughness 1.20 to 3.50 m.

The present invention relates to a polypropylene resin composition exhibiting an effect of lowering the gloss of an injection plastic product and exhibiting excellent mechanical properties. The polypropylene resin composition can be effectively applied to automobile interior plastic parts requiring low gloss characteristics, electronic products requiring matt exterior parts, and home appliances.

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

The present invention provides a low-gloss polypropylene resin composition, wherein the polypropylene resin composition may comprise an ethylene-propylene block copolymer resin.

According to one embodiment of the present invention, the ethylene-propylene block copolymer resin may be composed of a homopolypropylene polymer portion and an ethylene-propylene copolymer portion as a rubber component.

In the ethylene-propylene block copolymer resin, the homopolypropylene may have a melt index of 50 to 200 g / 10 min (ASTM D1238, 230 DEG C / 2.16 kg, Melt Index, MI) It can be varied within the above range depending on the melt index of the block copolymer.

The ethylene content of the ethylene-propylene block copolymer may be 10 to 25.0 mol% based on the total weight of the block copolymer resin, 14 to 21 mol%, and preferably 15 to 20 mol% %. ≪ / RTI > If the ethylene content is less than 10% by weight, the surface roughness of the injection-molded product of the polypropylene resin is low and it is difficult to exhibit low gloss characteristics. When the ethylene content is more than 25% by weight, the glossiness may be lowered. However, It is difficult to obtain a polypropylene resin composition that simultaneously satisfies low gloss.

The content of the ethylene-propylene copolymer as the rubber component is 8.0 to 18.0% by weight, preferably 10.0 to 17.0% by weight, based on the total weight of the block copolymer resin. If the content is less than 8.0 wt%, the effect of lowering the gloss may be insignificant due to the low rubber component content, and the impact strength may be lowered. If the content is more than 18.0 wt%, the bending strength and tensile strength may be relatively lowered. The content of the ethylene-propylene copolymer may be measured using a solvent extract, and the solvent may be a xylene extract.

The weight average molecular weight of the ethylene-propylene copolymer as the rubber component may be in the range of 300,000 to 800,000 Da, and may be in the range of 300,000 to 700,000 Da, preferably in the range of 300,000 to 600,000 Da . If the weight average molecular weight is less than 300,000 Da, the effect of reducing the gloss of the injection molded article of the polypropylene resin composition may be insignificant. If the weight average molecular weight exceeds 800,000 Da, it is difficult to control the melt index of the polypropylene resin composition, The surface quality of the product may be deteriorated due to the occurrence of a stain pattern on the surface of the product.

The ethylene-propylene copolymer as the rubber component may have an intrinsic viscosity of 3.0 to 8.0 dL / g and may be 3.0 to 6.0 dL / g, preferably 3.0 to 5.0 dL / g according to the embodiment of the present invention. have. If the intrinsic viscosity is less than 3.0 dL / g, the gloss reduction effect is poor. If the intrinsic viscosity exceeds 8.0 dL / g, it is difficult to produce an ethylene-propylene copolymer in a gas reactor according to the production method of the present invention.

The ethylene-propylene block copolymer resin composition may have a melt index of 30 to 110 g / 10 min (ASTM D1238, 230 DEG C / 2.16 kg, Melt Index, MI) g / 10 min, preferably 30 to 50 g / 10 min.

The ethylene-propylene block copolymer resin is a resin in which a homopropylene polymer portion and an ethylene-propylene copolymer portion are polymerized stepwise, and the polymerization can be carried out in the presence of a Ziegler-Natta catalyst. The polymerization method may be a method and reaction conditions commonly known in the technical field of the present invention such as a slurry method, a bulk method, a vapor phase method and the like. Specifically, the ethylene propylene block copolymer resin is produced by polymerizing homopolypropylene through two or more reactors in a first polymerization step, adding ethylene and propylene to the homopolypropylene produced in the second polymerization step, The copolymer portion can be polymerized. The first polymerization step and the second polymerization step may be carried out in the same polymerization reactor or in different polymerization reactors.

For example, the polymerization can be carried out in the presence of a catalyst system comprising a Ziegler-Natta catalyst and an external electron donor, and a gas phase polymerization reactor for synthesizing an ethylene-propylene copolymer and two or more bulk polymerization reactors for synthesizing homopolypropylene in the presence of hydrogen gas May be carried out in a polymerization facility.

The melt index in the last reactor of the homopolypropylene synthesized in two or more reactors synthesizing the homopolypropylene may be from 50 to 200 g / 10 min (measured at 230 DEG C, 2.16 Kg), as mentioned above . The melt index in each reactor for synthesizing two or more homopolypropylene can be operated so as to be reduced in turn, and conversely, the melt index in each reactor can be operated in the same manner. Next, the synthesized homopolypropylene is moved to a gas-phase reactor in which ethylene-propylene copolymerization is carried out, and ethylene and propylene are continuously introduced into the homopolypropylene solid component to continuously copolymerize with the homopolypropylene solid component to produce an ethylene propylene block copolymer have. The ratio of the ethylene content to the total gas in the gas phase reactor may be 0.30 to 0.90 (molar ratio), preferably 0.40 to 0.80, more preferably 0.50 to 0.70.

The Ziegler-Natta catalyst is MgCl ₂ A compound produced by supporting TiCl ₃ or TiCl ₄ on the carrier can be used. Alkylaluminum compounds are used as cocatalysts, for example, triethylaluminum, diethylchloroaluminum, tributylaluminum, trisisobutylaluminum, trioctylaluminum and the like, but they are not particularly limited in the present invention. The external electron donor is an organosilane compound, for example, diphenyldimethoxysilane, phenyltrimethoxysilane, phenylethyldimethoxysilane, phenylmethyldimethoxysilane, methoxytrimethylsilane, isobutyltrimethoxysilane, di Diisopropyldimethoxysilane, di-t-butyldimethoxysilane, dicyclopentyldimethoxysilane, cyclohexylmethyldimethoxysilane, dicyclohexyldimethoxysilane, and the like. In the present invention, Not limited.

The polypropylene resin composition may further include 0.1 to 0.5 parts by weight of a heat stabilizer based on 100 parts by weight of the polypropylene resin composition in order to increase the heat stability of the injection molded article. By weight, preferably 0.02 to 0.3 part by weight. If the content of the heat stabilizer is less than 0.1 parts by weight, it is difficult to secure long-term heat stability. If the content is more than 0.5 parts by weight, dissolution of the heat stabilizer may occur or cost efficiency may be deteriorated. Specific examples of the heat stabilizer include tetrakis (methylene (3,5-di-t-butyl-4-hydroxy) hydrosilylate), 1, 3,5-trimethyl-tris (3,5-di-t-butyl-4-hydroxybenzene), and tris (2,4-di-t-butylphenol) phosphite.

The polypropylene resin composition surface gloss when 2 mm measuring colorless gloss of 60 ^o angle of the flat plate specimens having a thickness of even (Gloss, 60 ^o) is a less than 65%, the arithmetic average surface roughness (Ra) of 60 To 160 nm, and the ten point average surface roughness (Rz) value may be 1.20 to 3.50 m. If the arithmetic mean surface roughness (Ra) value is less than 60 nm, the low-gloss characteristics are not exhibited. If the arithmetic mean surface roughness (Ra) is more than 160 nm, the appearance of the molded product is poor. In addition, when the surface glossiness (Gloss, 60 ^o ) exceeds 65%, low glossiness of the final product may be difficult to manifest.

The polypropylene resin composition according to the present invention may further contain conventional additives within the scope of the invention without departing from the scope of the present invention. For example, the polypropylene resin composition according to the present invention may contain a reinforcing material, filler, weathering stabilizer, antistatic agent, lubricant, slip agent, Pigments, dyes, and the like, but are not particularly limited in the present invention.

The polypropylene resin composition according to the present invention can be molded into a polypropylene resin by a conventional molding method such as injection molding or extrusion molding. The molded product can be applied to a plastic product which exhibits low gloss and excellent mechanical properties and is required to have a low gloss characteristic. For example, it can be used as an automobile interior plastic component, an electronic product requiring a matt exterior component, .

The present invention can be more specifically understood by the following examples, and the following examples are merely examples for illustrating the present invention and are not intended to limit the scope of protection of the present invention.

Example  1 to 5 and Comparative Example  1-5

(1) ethylene propylene Block copolymer  polymerization

Ziegler-Natta catalyst composed of TiCl ₄ and MgCl ₂ , dicyclopentyldimethoxysilane as external electron donor, and catalyst system with triethylaluminum added for activation of the catalyst. Among the four polymerization tanks arranged in series from the first to the third polymerization tank (Bulk polymerization reactor) to prepare homopolypropylene. Then, the resulting polymer was transferred to a fourth gas-phase polymerization reactor, ethylene and propylene were added thereto to carry out vapor phase polymerization, and the ethylene propylene block copolymer shown in Table 1 .

Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 * Melt index
(Homo PP) g / 10 min 80 84 92 140 195 48 50 42 185 110 ** Melt Index
(PP-EP) g / 10 min 32.5 33.5 40.3 62.2 105.2 30.3 30.0 28.8 26.0 61.8 T-C2 mol% 16.4 20.1 15.5 14.8 16.1 11.7 13.0 8.8 20.2 12.5 X.S. wt% 11.8 10.0 12.2 12.1 13.0 15.5 13.3 15.3 26.0 15.7 X.S.-IV dl / g 3.8 4.2 4.5 4.0 3.9 2.6 2.7 2.7 4.0 2.4 X.S.-Mw Da 303,000 321,000 327,000 317,000 310,000 210,000 219,000 21,7000 312,000 205,000

* Melt index: It is the melt index of homopolypropylene.

** Melt index: the melt index of the ethylene propylene block copolymer resin.

 (2) Evaluation of physical properties

The prepared ethylene propylene block copolymer resin was injection-molded into a specimen ASTM-4 and a 2 mm flat plate specimen, which were extruded at 190-230 ° C using a Wuzin 150-ton extruder.

Example 1 Example
2 Example 3 Example 4 Example 5 FM kgf / cm ² 14,300 13,700 14,300 14,100 15,000 IZOD @ RT kgf cm / cm 7.9 8.5 5.2 5.0 3.8 @ -20 ℃ kgf cm / cm 4.1 4.3 2.8 2.3 2.2 Tensile Strength @ yield kgf / cm2 270 265 270 265 275 Elongation % 170 140 110 70 50 Modulus kgf / cm ² 220 230 220 225 235 Hardness R scale 82 78 78 82 84 Gloss (60 ^o ) % 55 49 58 55 56 Arithmetic mean surface roughness (Ra) nm 95 103 98 99 102 10 Average surface roughness (Rz) ㎛ 2.30 2.45 2.41 2.24 2.40

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 FM kgf / cm ² 13,500 14,000 13,700 9,100 14,800 IZOD @ RT kgf cm / cm 8.0 7.1 7.1 51 5.1 @ -20 ℃ kgf cm / cm 4.0 3.8 3.8 9.0 2.3 Tensile Strength @ yield kgf / cm ² 270 265 265 190 275 Elongation % 230 290 290 440 90 Modulus kgf / cm ² 240 230 230 185 230 Hardness R scale 80 84 80 45 80 Gloss (60 ^o ) % 85 82 86 54 84 Arithmetic mean surface roughness (Ra) nm 37.0 40.9 33.5 108 34.4 10 Average surface roughness (Rz) ㎛ 1.11 1.18 1.16 2.10 1.22

Assessment Methods

(1) Melt index ( Melt index , g / 10 min)

Measured under conditions of 230 DEG C and 2.16 kg according to ASTM D 1238 conditions.

(2) Ethylene-propylene copolymer rubber xylene extract ( Xylene Soluble , X.S., wt.%)

The propylene-based mixed-phase resin was dissolved in xylene at a concentration of 1% at 140 ° C for 1 hour, extracted at room temperature for 2 hours, and then the weight thereof was measured and expressed as a percentage of the total weight of the propylene- .

(3) intrinsic viscosity of rubbery xylene extract ( Xylene Soluble  - intrinsic viscosity , X.S.-IV, dl / g%)

The intrinsic viscosity of the ethylene-propylene copolymer rubber was measured by dissolving in xylene at 150 캜 using an intrinsic viscometer.

(4) Rubberyxylene extract powder Weight average molecular weight ( Xylene Soluble - Weight  Average Molecular Weight , X.S.- Mw )

The average molecular weight of the ethylene-propylene copolymer rubber was calculated from the analytical results from the gel permeation chromatography apparatus by the calibration curve method using the reference polystyrene.

(5) Total ethylene content ( Total - ethylene , T- C2 , Mol%)

As the ethylene fraction of the entire resin composition, the ethylene content was measured using a characteristic peak at 720 and 740 cm ^-1 using an infrared absorption spectrum.

(6) Glossiness (%)

The amount of reflected light was measured at 60 ^o angle according to the ASTM D523 method.

(7) Surface roughness ( Ra , Rz )

And measured with an optical 25 magnification lens using a Veeco NT9100 3D profiler. The arithmetic average surface roughness Ra can be calculated as follows.

Where y _{i -} Means the distance from the center line to the top of the surface, and the arithmetic mean surface roughness means an arithmetic mean value of the absolute value of this distance.

The ten-point mean surface roughness Rz is the sum of the distances (absolute values) of the five distances farthest from the center line of the sample section at the center line in the measured area and the distance (absolute value) of the five distances farthest downward In addition, calculate by dividing by 5.

(8) Flexural modulus ( kg / Cm2)

ASTM D790 method.

(9) Izod ( IZOD ) Impact strength ( kgf / cm )

(23 占 폚) and low temperature (-20 占 폚) according to ASTM D256.

(10) Tensile strength ( Tensile test )

It was measured according to the ASTM D638 method.

As shown in Tables 1 to 3, when the results of Examples 1-5 and Comparative Examples 1-3 and 5 were compared, as the T-C2 content was increased, It can be seen that the amount decreases. In Example 1-2, XS-IV and XS-Mw were higher than Comparative Example 1-3, but the flexural strength (FM, Flexural Modulus) was 14,300 and 13,700, which was significantly different from Comparative Example 1-3 none. In addition, Izod impact strength can be confirmed to be almost the same at room temperature and low temperature (-20 ° C). Tensile Strength at Yield and modulus values were not significantly different from those of Comparative Example 1-3, but the elongation was also lowered in tensile properties.

Further, regarding the glossiness, the mechanical properties of Example 1-5 showed 62% and 55%, respectively, on the surface glossiness (Gloss, 60 ^o ) although they did not show a large difference when compared with Comparative Example 1-3 It is possible to obtain a result that the gloss of 36% is lower than that of Comparative Example 1-3. Particularly, the arithmetic mean surface roughness (Ra) in Example 1-2 shows a surface roughness which is much higher than that in Comparative Example 1-3 in which glossiness is high at 95 and 103 nm. The ten-point average surface roughness (Rz) also showed the same tendency, which was greater than 2.30 μm in Examples 1-2, but less than 1.2 μm in Comparative Examples 1-3 having high gloss.

The gloss (Gloss) did not show a large difference when Examples 1-5 and Comparative Example 4 were compared, but X.S. And the flexural strength and the tensile strength were much lower than those of Examples 1-5. This is the X.S. If the value is too high, the glossiness can be lowered, but the stiffness is very poor in terms of mechanical properties.

The present invention provides a low-gloss polypropylene resin composition comprising a homopolypropylene polymer and an ethylene-propylene rubber component, and the polypropylene resin composition can provide a plastic molded article excellent in rigidity and impact properties while having low gloss have.

Claims (8)

An ethylene-propylene block copolymer resin composed of a homopolypropylene polymer portion and an ethylene-propylene copolymer portion,
Wherein the ethylene-propylene block copolymer resin has a melt index of 30 to 110 g / 10 min (230 DEG C, 2.16 Kg) and an ethylene content of 11 to 25.0 mol%
Wherein the ethylene-propylene copolymer has an intrinsic viscosity of 3.0 to 6.0 dL / g and a weight average molecular weight of 300,000 to 800,000 Da.
The method according to claim 1,
Wherein the polypropylene resin composition has a surface glossiness (Gloss, 60 ^o _, colorless flat panel injection test piece) of 65% or less, an arithmetic average surface roughness (Ra) value of 60 to 160 nm, and a ten-point average surface roughness 1.20 to 3.50 占 퐉.
The method according to claim 1,
Wherein the homopolypropylene polymer has a melt index of 50 to 200 g / 10 min (230 DEG C, 2.16 Kg).
The method according to claim 1,
Wherein the polypropylene resin composition further comprises 0.1 to 0.5 parts by weight of a heat stabilizer based on 100 parts by weight of the polypropylene resin composition.
5. The method of claim 4,
Examples of the heat stabilizer include tetrakis (methylene (3,5-di-t-butyl-4-hydroxy) hydrosilylate), 1,3,5-trimethyl-tris (3,5- 4-hydroxybenzene) and tris (2,4-di-t-butylphenol) phosphite.
The method according to claim 1,
Wherein the ethylene-propylene block copolymer resin is polymerized using a Ziegler-Natta catalyst and an organosilane compound.
The method according to claim 1,
The ethylene-propylene block copolymer resin is prepared by polymerizing homopolypropylene in a first polymerization step and introducing ethylene and propylene into the homopolypropylene produced in the second polymerization step to polymerize the ethylene-propylene copolymer portion Polypropylene resin composition.
8. The method of claim 7,
Wherein the first polymerization step and the second polymerization step are carried out in the same reactor or in different reactors.