KR20200077150A - Polypropylene resin composition with improved transparency and odor properties and molded product comprising the same - Google Patents

Abstract

A polypropylene resin composition according to the present invention includes: a propylene-ethylene random copolymer; and a nucleating agent containing a hexitol-based nucleating agent and a sorbitol-based nucleating agent, wherein a weight ratio of the hexitol-based nucleating agent to the sorbitol-based nucleating agent is 1 : 2.5 to 2.5 : 1. The polypropylene resin composition according to the present invention has advantages of reducing off-flavor and enabling production of molded articles having excellent transparency.

Description

A polypropylene resin composition with improved transparency and odor characteristics and a molded product comprising the same{POLYPROPYLENE RESIN COMPOSITION WITH IMPROVED TRANSPARENCY AND ODOR PROPERTIES AND MOLDED PRODUCT COMPRISING THE SAME}

The present invention relates to a polypropylene resin composition having improved transparency and odor characteristics and a molded article comprising the same.

Propylene-ethylene random copolymers are widely used in products requiring transparency such as food containers, stationery, films, and sheets. However, the transparency of the propylene-ethylene random copolymer itself is not good, so an external nucleating agent is added in the extrusion process after polymerization of the propylene-ethylene random copolymer to increase the crystallization temperature and crystallization rate of the propylene-ethylene random copolymer. A method of reducing transparency by reducing the crystal sphere size is commercially used, and generally, hexitol-based nucleating agents, sorbitol-based nucleating agents, or nonitol-based nucleating agents are used.

Japanese Unexamined Patent Publication No. 2007-022924 relates to a odor and taste transferability inhibitor generated from diacetal and a diacetal composition comprising the inhibitor, wherein (A) at least one di-type represented by formula (1) Acetal and (B) a sorbitan C8-C22 fatty acid ester and a polyoxyethylene sorbitan C8-C22 fatty acid ester is at least one member selected from the group consisting of a particulate or powdered diacetal composition The contents are disclosed.

Republic of Korea Patent Publication No. 2013-0009738 relates to a transparent agent composition containing a sorbitol compound and a method for producing a polypropylene-based resin composition using the sorbitol compound, wherein d ₉₇ is 30 μm or more and 200 μm or less in general particle size (I ) Is a mixture of 100 parts by mass of dibenzylidene sorbitol compound and 5 to 200 parts by mass of tetrakis[3(3,5-di-tertbutyl-4-hydroxyphenyl) propionyloxymethyl]methane , Discloses a content of a clearing agent composition in which the sum of both components is 50% by mass or more of the mixture.

However, in the case of a polypropylene resin composition containing a hexitol-based nucleating agent, the effect of improving the transparency is insignificant when the content of the hexitol-based nucleating agent is increased, and there is a problem that odor occurs according to structural characteristics.

In addition, when using a sorbitol-based nucleating agent, there is a problem that transparency is lowered when the content is increased.

In order to solve this, attempts have been made to develop a polypropylene resin composition using a nonitol-based transparent nucleating agent, but in the case of a non-nuitol-based nucleating agent, it is about 2 to 3 times more expensive than a conventional nucleating agent, and exhibits a characteristic that transparency is significantly reduced when mixed with other nucleating agents. It has been applied and used only by itself.

Accordingly, there is a need to develop a polypropylene resin composition having excellent transparency and reduced volatile substances that cause odor.

Japanese Patent Publication No. 2007-022924 (2007.02.01.) Republic of Korea Patent Publication No. 2013-0009738 (2013.01.23.)

The present invention is to provide a polypropylene resin composition having excellent transparency and reduced odor.

In addition, the present invention is to provide a polypropylene molded article having excellent transparency and less odor.

The present invention is a propylene-ethylene random copolymer; And a nucleating agent containing a hexitol-based nucleating agent and a sorbitol-based nucleating agent, wherein the weight ratio of the hexitol-based nucleating agent to the sorbitol-based nucleating agent is 1:2.5 to 2.5:1.

In addition, the present invention provides a molded article comprising a cured product of the polypropylene resin composition described above.

The polypropylene resin composition according to the present invention has an advantage of being capable of manufacturing a molded article having excellent transparency and reduced occurrence of off-flavor.

In addition, the polypropylene resin molded article according to the present invention has the advantage of excellent transparency and reduced odor.

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

In the present invention, when a part “includes” a certain component, it means that the component may further include other components, not to exclude other components, unless otherwise stated.

<Polypropylene resin composition>

One aspect of the present invention, a propylene-ethylene random copolymer; And a nucleating agent containing a hexitol-based nucleating agent and a sorbitol-based nucleating agent; wherein the weight ratio of the hexitol-based nucleating agent to the sorbitol-based nucleating agent is 1:2.5 to 2.5:1.

Propylene-ethylene random copolymer

The polypropylene resin composition according to the present invention comprises a propylene-ethylene random copolymer.

The propylene-ethylene random copolymer is a crystalline copolymer containing propylene as a main component, for example, propylene and ethylene are simultaneously introduced into a polymerization reactor, and catalysts such as triethyl aluminum, diamond, metallocene, and Ziegler-Natta, and After injecting the silane-based electron donor, the reaction temperature can be prepared by bulk polymerization of slurry at 65-75°C and 32-35 K/G atmospheric pressure, and the melt index can be controlled by hydrogen.

The polymerization reactor may be made of any one of a combination of loop type, loop type, and gas phase reactors.

The propylene-ethylene random copolymer may serve to maintain mechanical strength of the polypropylene resin composition and maintain heat resistance and transparency.

In one embodiment of the present invention, with respect to 100 parts by weight of the propylene-ethylene random copolymer, the repeating unit derived from ethylene is 0.1 to 10 parts by weight, preferably 2.0 to 5.0 parts by weight, more preferably 3.0 to 4.0 parts by weight.

When the ethylene-derived repeating unit is within the above range, it has an advantage of being capable of producing a molded article having an appropriate crystallinity and excellent transparency and excellent mechanical properties.

The propylene-ethylene random copolymer may be included in 90 to 99.99 parts by weight, preferably 93 to 99.98 parts by weight, and more preferably 95 to 99.98 parts by weight based on 100 parts by weight of the entire polypropylene resin composition.

When the propylene-ethylene random copolymer is included in the above range, it is preferable because it has the advantage of producing a molded article having excellent mechanical properties.

In another embodiment of the present invention, the propylene-ethylene random copolymer is 230 ℃, under the conditions of 2.16kg load, the melt index is 5g/10min to 100g/10min, preferably 10g/10min to 50g/10min, More preferably, it may be 28g/10min to 38g/10min.

The melt index is a property related to injection molding of the propylene-ethylene random copolymer.

When the melt index of the propylene-ethylene random copolymer is within the above range, it has the most suitable flowability during injection molding, thereby improving injection molding, reducing defect rate, and improving productivity due to reduced cycle time. There is this.

The propylene-ethylene random copolymer may be polymerized in a conventional slurry loop polymerization process, such as a speripol polymerization process, but is not limited thereto.

Nuclear

The polypropylene resin composition according to the present invention includes a nucleating agent containing a hexitol-based nucleating agent to a sorbitol-based nucleating agent in a weight ratio of 1:2.5 to 2.5:1.

The hexitol-based nucleating agent, when included in an excessive amount, may decompose into aromatic aldehydes and polyhydric alcohol components and cause odor as benzaldehyde is generated.

The sorbitol-based nucleating agent, if included in an excessive amount, has a problem that it is difficult to ensure sufficient transparency.

In the present invention, by using the hexitol-based nucleating agent and the nucleating agent containing the sorbitol-based nucleating agent in a weight ratio in the above range, it is possible to provide a polypropylene resin composition capable of producing a molded article having excellent transparency and reduced odor. Incidentally, when the same amount of nucleating agent is used alone, heat resistance is improved and mechanical properties (tensile strength) are improved.

The hexitol-based nucleating agent to the sorbitol-based nucleating agent is preferably 1:2.3 to 2.3:1 by weight, more preferably 1:2.1 to 2.2:1, more preferably 1.5:1 to 2.2:1, most preferably It may be included in a weight ratio of 1.9:1 to 2.1:1, in this case, it has the best compatibility and dispersibility between nuclear agents, and has the advantage of reducing transparency and reducing volatile substances that cause odor.

Specifically, the hexitol-based nucleating agent is 1,3:2,4-bis-O-[(4-methylphenyl)methylene]-hexitol (Hexitol,1,3:2,4-bis-O-[(4- methylphenyl)methylene]-), but is not limited thereto. However, in this case, the desired effect is maximized and desirable.

The sorbitol-based nucleating agent is 1,3:2,4-bis(3,4-dimethyldibenzylidene) sorbitol (1,3:2,4-Bis(3,4-dimethyldibenzylidene) Sorbitol), bis(p- Methyldibenzylidene) sorbitol (Bis(p-methyldibenzylidene) Sorbitol), substituted Dibenzylidene Sorbitol, 1,3:2,4-bis(3,4-dimethylbenzylbenzylideno)sorbitol(1 ,3:2,4-bis(3,4-dimethylobenzylideno)sorbitol).

Specifically, the sorbitol-based nucleating agent may be 1,3:2,4-bis(3,4-dimethyllobenzylideno) sorbitol (1,3:2,4-bis(3,4-dimethylobenzylideno) sorbitol), In this case, the desired effect is maximized, which is desirable.

In another embodiment of the present invention, the nucleating agent may be included in an amount of 0.1 to 0.5 parts by weight based on 100 parts by weight of the total polypropylene resin composition. When the nucleating agent is included within the above range, it has excellent compatibility and dispersibility between nucleating agents, and is advantageous because it has the effect of improving transparency and reducing volatile substances that cause odor.

In another embodiment of the present invention, the hexitol-based nucleating agent is 0.05 to 0.5 parts by weight, preferably 0.08 to 0.4 parts by weight, more preferably 0.08 to 0.25 parts by weight, based on 100 parts by weight of the total polypropylene resin composition. It can be included as a wealth.

When the hexitol-based nucleating agent is included within the above range, it is preferable because it is more effective in expressing transparency.

In another embodiment of the present invention, the sorbitol-based nucleating agent is contained in 0.3 parts by weight or less, preferably 0.05 to 0.25 parts by weight, more preferably 0.08 to 0.15 parts by weight based on 100 parts by weight of the total polypropylene resin composition. Can.

In the case of the sorbitol-based nucleating agent, if it exceeds 0.3 parts by weight, the transparency may be deteriorated. Therefore, the sorbitol-based nucleating agent is preferably included in 0.3 parts by weight or less based on 100 parts by weight of the total polypropylene resin composition. .

Since the polypropylene resin composition according to the present invention contains a nucleating agent containing a hexitol-based nucleating agent and a sorbitol-based nucleating agent in a weight ratio of 1:2.5 to 2.5:1, there is an advantage that it is possible to impart excellent transparency while reducing odor.

The polypropylene resin composition according to the present invention may include additives conventionally used in the art within a range that does not significantly inhibit the effects of the present invention. For example, antioxidants, heat stabilizers, neutralizing agents, processing stabilizers, ultraviolet absorbers, antistatic agents, anti-blocking agents, slip agents, weathering agents, lubricants, processing aids, metal soaps, antibacterial agents, plasticizers, flame retardants, crosslinking agents, crosslinking aids, high brightness agents And the like, but is not limited thereto.

Depending on the use of the polypropylene resin composition, the additive may be appropriately added and used within a range that does not impair the object of the present invention. For example, the additive may be included in an amount of 0.1 to 10 parts by weight, preferably 0.1 to 5 parts by weight, and more preferably 0.1 to 1 part by weight based on 100 parts by weight of the total polypropylene resin composition, but is not limited thereto.

Examples of the method for producing the polypropylene resin composition of the present invention include a method of melt-kneading each component, for example, a method of using a kneader such as a single-screw extruder, twin-screw extruder, van barry mixer, heat roll, or the like. Can.

Examples of the shape of the polypropylene resin composition obtained in the present invention include a strand shape, a sheet shape, a flat plate shape, and a pellet shape in which the strand is cut to an appropriate length. In order to apply the polypropylene resin composition of the present invention to molding processing, it may preferably be in the form of pellets having a length of 1 to 50 mm as a shape from the viewpoint of production stability of the obtained molded article.

In another embodiment of the present invention, the polypropylene resin composition is 23 °C in accordance with ASTM D1003 evaluation method, under 50% relative humidity, the thickness of the specimen measured when the thickness of 1mm can be 7 or less, preferably 6 or less In this case, it is preferable because it has the advantage of excellent transparency.

In another embodiment of the present invention, the polypropylene resin composition is 23 ℃, according to ASTM D1003 evaluation method, at a relative humidity of 23%, 50%, the thickness of the specimen measured when the thickness of 2mm may be 30 or less, preferably 26 or less In this case, when applying an actual injection product, it is preferable because it has the advantage of maintaining its transparency even in a thick product.

In another embodiment of the present invention, the polypropylene resin composition may have a transmittance of 80% or more, preferably 86% or more, more preferably 90% or more, when measured at a thickness of 1 mm according to the ASTM D1003 method. In this case, it is preferable because it has the advantage of excellent surface gloss.

In another embodiment of the present invention, the polypropylene resin composition may have a transmittance of 75% or more, preferably 80% or more, more preferably 83% or more, when measured at a thickness of 2 mm according to ASTM D1003 method. have. When the transmittance satisfies the above range, there is an advantage of excellent surface gloss.

The polypropylene resin composition according to the present invention has the advantage of less fume generation.

<Molded product>

Another aspect of the present invention relates to a molded article comprising the polypropylene resin composition described above.

Specifically, a molded article can be produced by various molding methods using the polypropylene-based resin composition of the present invention, and the shape, size, and the like of the molded article can be appropriately determined.

Examples of the method for manufacturing the molded article include an injection molding method, a press molding method, a vacuum molding method, a foam molding method, an extrusion molding method, etc., which are usually used in industry, and the polypropylene-based resin composition of the present invention is also used depending on the purpose. And a molding method in which polypropylene-based resins of the same kind or different kinds are mixed with other resins, a method of co-extrusion molding, and the like.

The molded product may be any one of a refrigerated container, a frozen container, a multi-purpose storage box, an interior/exterior material for an automobile, a food packaging container, a bottle cap, a packaging film, a protective film, a deco sheet, a retort pouch, a medicine container, and an extrusion blow molded product, but is not limited thereto. Does not work.

Specifically, in the present invention, the molded article has high transparency and reduced odor characteristics, and at the same time has excellent resin flow, heat resistance, and mechanical strength, so it is a transparent food container, tableware, drawer, stationery, cosmetic container, household goods, thin film injection It can be useful for products (TWIM, Thin Wall Injection Molding).

The molded article according to the present invention includes a propylene-ethylene random copolymer; And a nucleating agent containing a hexitol-based nucleating agent and a sorbitol-based nucleating agent; since the hexitol-based nucleating agent and the sorbitol-based nucleating agent are made of a polypropylene resin composition having a weight ratio of 1:2.5 to 2.5:1, odor is reduced. It has the advantage of being excellent in transparency.

Hereinafter, examples will be described in detail to specifically describe the present specification. However, the embodiments according to the present specification may be modified in various other forms, and the scope of the present specification is not interpreted to be limited to the embodiments described below. The embodiments of the present specification are provided to more fully describe the present specification to those skilled in the art. In addition, "%" and "part" which represents content below are on a weight basis unless otherwise specified.

Example And Comparative example : Preparation of polypropylene resin composition

Ethylene-propylene random copolymer having an ethylene content of 3.5% and a melt flow index (MI) of 35 g/10 min (230° C., 2.16 kg load), mixed with a Henschel mixer using a neutralizing agent, an antioxidant, an antistatic agent, and a nuclear agent Then, the mixture was melt extruded at a screw rotation speed of 125 to 128 rpm, C1/C2/C3/C4/D=180/200/210/220/210°C using a 40mmΦ single extruder. Pellet-type polypropylene resin compositions according to Examples and Comparative Examples were prepared. At this time, the weights of the hexitol-based nucleating agent and the sorbitol-based nucleating agent with respect to 100 parts by weight of the total polypropylene resin composition according to Examples and Comparative Examples are shown in Table 1 below.

Experimental Example

The polypropylene resin composition according to Examples and Comparative Examples was 180 ton electric injection machine, injection temperature 180/190/200/210°C, injection pressure/pressurization 50-60MPa, injection speed 40-50mm/s, injection time 10s, cooling Under the condition of time 40 seconds, ASTM physical property specimens were prepared by injection.

In the case of Haze (cloudiness, permeability) specimen, a 150 ton hydraulic injection machine for a polypropylene resin composition according to Examples and Comparative Examples, injection temperature 200/210/220/230°C, injection pressure 50-55-55-50-45kg/ Haze specimens were prepared by injecting Haze specimens under the conditions of cm ² , holding pressure 55 kg/m ² , injection speed 40-45-45-40-35%, injection time 8 seconds, and cooling time 20 seconds.

After aging each prepared specimen at 24° C. for 60 hours at 60% RH, the tensile strength, flexural strength/flexural modulus, Izod impact strength, thermal deformation temperature, cloudiness/permeability are measured and shown in Table 1 below. Did.

In addition, the relative fume contents of Comparative Examples and Examples were measured and are shown in Table 1 below.

(1) Tensile strength

Specimens prepared according to Examples and Comparative Examples were measured based on ASTM D638.

(2) Flexural strength/flexural modulus

Specimens prepared according to Examples and Comparative Examples were measured based on ASTM D790.

(3) Izod impact strength

Specimens prepared according to Examples and Comparative Examples were measured based on ASTM D256 (23° C., notched).

(4) Heat deflection temperature

Specimens prepared according to Examples and Comparative Examples were measured based on ASTM D648 (4.6kgf/cm ² ).

(5) Cloudiness/Transmittance

Specimens prepared according to Examples and Comparative Examples were measured using ASTM D1003 standard, 1 mmT/2mmT Haze specimens.

(6) Relative Fume content

Specimens prepared according to Examples and Comparative Examples were measured for volatiles after pretreatment at 80°C for 120 minutes using GC-MS Headspace.

Item unit Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Example 1 Example 2 Example 3 Example 4 Hexitol-based nuclear agent ¹⁾ (Parts by weight) 0.2 0.3 - - 0.27 0.08 0.1 0.2 0.1 0.25 Sorbitol-based nuclear agent ²⁾ (Parts by weight) - - 0.2 0.3 0.1 0.25 0.2 0.1 0.25 0.1 The tensile strength kgf/cm ² 309 316 308 312 318 320 316 324 320 320 Flexural strength kgf/cm ² 368 404 423 427 397 420 407 406 412 404 Flexural modulus kgf/cm ² 13,000 13,700 13,300 13,500 13,200 13,300 13,100 13,300 13,300 13,200 Izod impact strength kgcm/cm 3.3 3.2 3.3 3.3 3.2 3.3 3.3 3.2 3.2 3.2 Heat deflection temperature ℃ 90 96 116 102 110 108 105 116 110 102 Blur 1mmT
(%) 6.7 6.3 7.0 9.9 6.5 7.4 5.5 5.4 6.8 5.7 2mmT
(%) 31 27 34 39 28 35 26 23 30 26 Transmittance 1mmT
(%) 90 90 90 90 90 90 90 90 90 90 2mmT
(%) 83 83 83 83 83 83 83 83 83 83 Relative Fume content Fume
(%) 95 100 74 70 92 86 89 68 89 92 1) 1,3:2,4-bis-O-[(4-methylphenyl)methylene]-Hexitol
2) 1,3:2,4-bis(3,4-dimethylobenzylideno)sorbitol

Referring to Comparative Examples 1 to 4 of Table 1, when the hexitol-based nucleating agent is used, it has an effect of improving the transparency of the nucleating agent, but it can be seen that the degree is insignificant, and when using the sorbitol-based nucleating agent, the nucleating agent It can be seen that there is no effect of improving the transparency according to the increase, but rather the transparency is lowered.

Referring to Comparative Examples 2, 4 and Examples 1 and 3, in which the total content of the nucleating agent is 0.3 parts by weight based on 100 parts by weight of the polypropylene resin composition, the effect of improving transparency according to the increase in the amount of the nucleating agent is negligible when hexitol-based nucleating agent is applied alone, It can be seen that the odor increase is accompanied by an increase in the content (Comparative Examples 1 and 2). When applied alone, the sorbitol-based nucleating agent has little odor, but it can be seen that transparency decreases with increasing content (Comparative Examples 3 and 4). There is a limitation in improving transparency when two types of nucleating agents are applied alone, but it can be seen that it is effective in improving transparency when mixing is applied in a weight ratio according to the present invention (Examples 1 and 2), and the odor improvement effect compared to the application alone ( Relative Fume content reduction) can be confirmed (Example 2). Particularly, in the case of Example 2, the cloudyness of a thickness of 2 mmT was significantly reduced to show excellent transparency, which means that the transparency can be maintained even in a thick product when an actual injection product is applied. In addition, it has excellent mechanical properties according to the improvement of the thermal deformation temperature and tensile strength, and tends to reduce the volatile content by up to 30%, so it can provide specific information on the combination of improved transparency and odor when considering the design of the actual product. have.

Claims (7)

Propylene-ethylene random copolymers; And
Nucleating agent containing a hexitol-based nucleating agent and sorbitol-based nucleating agent; includes,
The weight ratio of the hexitol-based nucleating agent to the sorbitol-based nucleating agent is 1:2.5 to 2.5:1, a polypropylene resin composition. According to claim 1,
The nucleating agent is contained in 0.1 to 0.5 parts by weight based on 100 parts by weight of the total polypropylene resin composition. According to claim 1,
The sorbitol-based nucleating agent is a polypropylene resin composition that is contained in 0.3 parts by weight or less based on 100 parts by weight of the total polypropylene resin composition. According to claim 1,
The hexitol-based nucleating agent is 1,3:2,4-bis-O-[(4-methylphenyl)methylene]-hexitol (Hexitol,1,3:2,4-bis-O-[(4-methylphenyl)methylene ]-). According to claim 1,
The sorbitol-based nucleating agent is poly that contains 1,3:2,4-bis(3,4-dimethyllobenzylideno) sorbitol (1,3:2,4-bis(3,4-dimethylobenzylideno) sorbitol) Propylene resin composition. According to claim 1,
The polypropylene resin composition is 23 ℃, under 50% relative humidity, according to ASTM D1003 evaluation method, the blurring of the specimen measured at 1 mm thickness is 7 or less, the haze of the specimen measured at 2 mm thickness is 30 or less Polypropylene resin composition. A molded article comprising the polypropylene resin composition according to claim 1.