KR20220048537A - Polypropylene Resin Composition with Excellent Transparency and Article Molded Therefrom - Google Patents

Abstract

The present invention relates to a polypropylene resin composition and a molded article prepared therefrom. The polypropylene resin composition according to an embodiment of the present invention has an excellent balance of transparency and heat resistance and has little reduction in transparency when stored at high temperatures or for a long time. The molded article prepared from such a polypropylene resin composition has an excellent balance of transparency and heat resistance and thus can be used in various fields as materials for films, pipes, electric wires, automobile interior/exterior parts, home appliance parts, and construction/industrial materials.

Description

Polypropylene Resin Composition with Excellent Transparency and Article Molded Therefrom

The present invention relates to a polypropylene resin composition and a molded article prepared therefrom. In detail, the present invention relates to a polypropylene resin composition having excellent transparency and little decrease in transparency due to high temperature or long-term storage, and a molded article manufactured therefrom.

Polypropylene resin, a type of general-purpose resin, is not only economical, but also has excellent mechanical properties, moldability and chemical resistance, so it is widely used as a material for films, pipes, automobile interior and exterior parts, electrical and home appliance parts, and construction and industrial materials. is used sparingly.

However, the polypropylene resin is a crystalline resin and has high rigidity, but has poor transparency compared to an amorphous resin, thereby limiting its use range. In order to improve the transparency of the polypropylene resin, attempts have been made to prepare an ethylene-propylene random copolymer by adding an ethylene comonomer in the polypropylene polymerization step. In this case, as the content of ethylene increases, the transparency of the resin is improved, but there is a problem in that the heat resistance is poor and the transparency is sharply decreased during high temperature or long-term storage.

Accordingly, there is a demand for the development of a polypropylene resin composition that has excellent balance between transparency and heat resistance and has little decrease in transparency during high temperature or long-term storage.

Accordingly, an object of the present invention is to provide a polypropylene resin composition having excellent balance between transparency and heat resistance and having little decrease in transparency during high temperature or long-term storage.

Another object of the present invention is to provide a molded article prepared from the above polypropylene resin composition.

According to an embodiment of the present invention for achieving the above object, including the crystalline ethylene-propylene random copolymer resin, the ratio of the solvent extract content to the ethylene content in the crystalline ethylene-propylene random copolymer resin based on weight% This 1.0-1.8 polypropylene resin composition is provided.

In an embodiment of the present invention, the solvent extract content in the crystalline ethylene-propylene random copolymer resin may be 1.0 to 12.5 wt%, and the ethylene content may be 1.0 to 7.0 wt%.

In an embodiment of the present invention, the melt index of the crystalline ethylene-propylene random copolymer resin when measured at 230° C. under a load of 2.16 kg may be 1 to 100 g/10 min.

In an embodiment of the present invention, the polydispersity index (PI) of the crystalline ethylene-propylene random copolymer resin may be 2.5 to 5.0 as measured by an oscillatory shear test method.

In an embodiment of the present invention, the melting temperature of the crystalline ethylene-propylene random copolymer may be 130° C. or higher.

The polypropylene resin composition according to an embodiment of the present invention is one selected from the group consisting of antioxidants, neutralizers, antiblocking agents, reinforcing materials, fillers, weathering stabilizers, antistatic agents, lubricants, slip agents, nucleating agents, flame retardants, pigments and dyes The above additives may be further included.

In an embodiment of the present invention, the polypropylene resin composition comprises, based on 100 parts by weight of the composition, tetrakis(methylene(3,5-di-t-butyl-4-hydroxy)hydrosilylate), 1,3, at least one antioxidant selected from the group consisting of 5-trimethyl-tris(3,5-di-t-butyl-4-hydroxy benzene) and tris(2,4-di-t-butylphenyl)phosphite; It may be further included in an amount of 0.05 to 0.2 parts by weight.

In an embodiment of the present invention, the polypropylene resin composition, based on 100 parts by weight of the composition, dibenzylidene sorbitol, dimethylbenzylidene sorbitol, 1,3:2,4-bis(3) ,4-dimethylobenzylideno)sorbitol (1,3:2,4-bis(3,4-dimethylobenzylideno)sorbitol) and 1,2,3-tridesoxy-4,6:5,7-bis-O -[(4-propylphenyl)methylidene]nonitol (1,2,3-tridesoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]nonitol) It may further include one or more nucleating agents in an amount of 0.01 to 1 part by weight.

According to another embodiment of the present invention, a polypropylene resin molded article prepared by molding the above polypropylene resin composition is provided.

In an embodiment of the present invention, the polypropylene resin molded article may be selected from the group consisting of films, pipes, household goods, automobile interior/exterior parts, home appliance parts, and construction/industrial materials.

The polypropylene resin composition according to the embodiment of the present invention has excellent transparency and little decrease in transparency during high temperature or long-term storage, so materials such as films, pipes, electric wires, automobile interior and exterior parts, home appliance parts and construction and industrial materials can be used in various fields.

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

The polypropylene resin composition according to an embodiment of the present invention includes a crystalline ethylene-propylene random copolymer resin, wherein the ratio of the solvent extract content to the ethylene content in the crystalline ethylene-propylene random copolymer resin based on weight% is 1.0 ~1.8. When the ratio of the solvent extract content (wt%) to the ethylene content (wt%) in the crystalline ethylene-propylene random copolymer resin is less than 1.0, the transparency of the resin is deteriorated. On the other hand, when this ratio exceeds 1.8, the heat resistance of the resin composition may be deteriorated, and the transparency of the resin composition may be rapidly deteriorated during high temperature or long-term storage.

In an embodiment of the present invention, the solvent extract content in the crystalline ethylene-propylene random copolymer resin may be 1.0 to 12.5 wt%, and the ethylene content may be 1.0 to 7.0 wt%.

Here, the content of the solvent extract in the crystalline ethylene-propylene random copolymer resin is obtained by dissolving the ethylene-propylene random copolymer resin in xylene at a concentration of 1% by weight at 140° C. for 1 hour, and then after 2 hours at room temperature. It can be measured from the extracted weight. When the content of the solvent extract is less than 1.0% by weight, the transparency of the resin composition is lowered, and when the content exceeds 12.5% by weight, the stickiness of the resin composition becomes severe, making processing difficult and heat resistance is lowered.

In addition, the ethylene content in the crystalline ethylene-propylene random copolymer resin can be measured using the characteristic peaks of 720 cm ^-1 and 730 cm ^-1 using the infrared absorption spectrum. When the content of ethylene is less than 1.0% by weight, the effect of improving transparency of the resin composition by adding ethylene is small. On the other hand, when the content of ethylene exceeds 7.0 wt%, the heat resistance of the resin composition is low, and thus transparency may be greatly reduced during long-term storage.

In an embodiment of the present invention, the melt index (MI) of the crystalline ethylene-propylene random copolymer when measured at 230° C. under a load of 2.16 kg according to ASTM D1238 is 1 to 100 g/10 min, preferably 1 to 80 g/10 min, more preferably 3 to 50 g/10 min. The higher the melt index, the higher the fluidity of the resin composition. However, when the melt index exceeds 100 g/10 min, the resin composition becomes more sticky and the viscosity is too low, making it difficult to mold the product. On the other hand, when the melt index is less than 1 g/10 min, the viscosity of the resin composition increases, so that the pressure during processing is too high, making molding difficult.

In an embodiment of the present invention, the melting temperature of the crystalline ethylene-propylene random copolymer may be 130° C. or higher. When the melting temperature is less than 130° C., the heat resistance of the resin composition is low, which is not preferable.

In an embodiment of the present invention, the polydispersity index (PI) of the crystalline ethylene-propylene random copolymer resin may be 2.5 to 5.0 as measured by an oscillatory shear test method. The polydispersity index can be obtained by calculating Gc (the intersection of the curves of storage modulus (G') and loss modulus (G")) obtained in the vibration shear experiment by Equation 1 below.

[Equation 1]

Polydispersity Index (PI) = 10 ⁶ /Gc

When the polydispersity index is less than 2.5, the processability of the resin composition makes it difficult to mold the product, whereas when the polydispersity index exceeds 5.0, the transparency of the resin composition may be lowered, which is not preferable.

There is no particular limitation on the method for preparing the crystalline ethylene-propylene random copolymer according to the embodiment of the present invention, and the method for preparing the crystalline ethylene-propylene random copolymer known in the art to which the present invention pertains is modified as it is or as appropriate. can be used by For example, a bulk polymerization method, a solution polymerization method, a slurry polymerization method, a gas phase polymerization method, etc. can be used, and either a batch type or a continuous type is possible.

Specifically, one or more bulk reactors and one or more gas phase reactors are connected in series to Mitsui's Hypol process, which can continuously polymerize, or two or more gas phase reactors are connected in series A crystalline ethylene-propylene random copolymer can be prepared by a polymerization method known to those skilled in the art using Grace's Unipol process that can be continuously polymerized.

In an embodiment of the present invention, the crystalline ethylene-propylene random copolymer may be polymerized in the presence of a Ziegler-Natta catalyst. In this case, the catalyst may be prepared by reacting a titanium compound with a phthalate-based internal electron donor on a dialkoxymagnesium carrier, and an organic aluminum compound (eg, triethylaluminum) as a co-catalyst and dialkyldialkoxysilane as an external electron donor It is preferable to use a system compound (eg, dicyclopentyldimethoxysilane), but is not limited thereto.

The polypropylene resin composition according to the embodiment of the present invention may further include conventional additives within the scope of the present invention. For example, antioxidants, neutralizers, antiblocking agents, reinforcing materials, fillers, weathering stabilizers, antistatic agents, lubricants, slip agents, nucleating agents, flame retardants, pigments and dyes, etc. may include, but are not limited thereto.

In an embodiment of the present invention, the polypropylene resin composition may further include an antioxidant to increase its heat resistance stability. In this case, the antioxidant may be added in an amount of 0.05 to 0.2 parts by weight, preferably 0.05 to 0.1 parts by weight, based on 100 parts by weight of the polypropylene resin composition. If the content of the antioxidant is less than 0.05 parts by weight, it is difficult to ensure long-term thermal stability. On the other hand, even if the content of the heat-resistant stabilizer exceeds 0.2 parts by weight, the heat-resistance stability is not further improved, and the economic feasibility of the product may be lowered, which is not preferable.

As the above antioxidant, a phenol-based antioxidant, a phosphite-based antioxidant, etc. may be used, and specifically, tetrakis (methylene (3,5-di-t-butyl-4-hydroxy) hydrosilylate), 1 , at least one selected from the group consisting of 3,5-trimethyl-tris(3,5-di-t-butyl-4-hydroxybenzene) and tris(2,4-di-t-butylphenyl)phosphite However, it is not limited thereto.

In an embodiment of the present invention, the polypropylene resin composition may further include a nucleating agent to increase its transparency. In this case, the nucleating agent may be added in an amount of 0.01 to 1 parts by weight, preferably 0.03 to 0.3 parts by weight, based on 100 parts by weight of the polypropylene resin composition. When the content of the nucleating agent is less than 0.01 part by weight, the effect of improving transparency is small, and when this content exceeds 1 part by weight, the transparency is not further improved, and the economic feasibility of the product may be lowered, which is not preferable.

As a gastric nucleating agent, organic phosphate, a sorbitol derivative, a nonitol derivative, etc. may be used, and specifically, dibenzylidene sorbitol, dimethylbenzylidene sorbitol, 1,3 :2,4-bis(3,4-dimethylobenzylideno)sorbitol (1,3:2,4-bis(3,4-dimethylobenzylideno)sorbitol) and 1,2,3-tridesoxy-4,6 :5,7-bis-O-[(4-propylphenyl)methylidene]nonitol (1,2,3-tridesoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene] It may include one or more selected from the group consisting of nonitol), but is not limited thereto.

According to another embodiment of the present invention, there is provided a polypropylene resin molded article produced by molding the polypropylene resin composition of the present invention.

There is no particular limitation on a method for manufacturing a molded article from the polypropylene resin composition according to an embodiment of the present invention, and a method known in the art to which the present invention pertains may be used. For example, a polypropylene resin molded article may be manufactured by molding the polypropylene resin composition according to an embodiment of the present invention by a conventional method such as injection molding, extrusion molding, or casting molding.

The polypropylene resin molded article according to an embodiment of the present invention has excellent transparency and excellent heat resistance and transparency retention ability, so it is used as a material for films, pipes, electric wires, automobile interior and exterior parts, home appliance parts, construction and industrial materials, etc. It can be used in various ways.

Example

Hereinafter, the present invention will be described in more detail through Examples and Comparative Examples. However, the following examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.

As shown in Tables 1 and 2, propylene or ethylene-propylene random copolymers having different ethylene and solvent extract contents were prepared in a process in which a bulk reactor and a gas phase reactor were connected in series. To this resin, 2,000 ppm of NX8000K as a nucleating agent, 1,000 ppm of Iganox 1010 as a phenolic antioxidant, 1,000 ppm of Iganox 168 as a phosphate antioxidant, and 500 ppm of calcium stearate as a catalyst neutralizer were added, and melted through a twin screw extruder at 210°C By mixing and pelletizing, a polypropylene resin composition was prepared. Thereafter, an injection specimen was manufactured at a temperature of 210° C. using an injection molding machine (Engel, 180 tons).

test example

The polypropylene resin composition obtained in each Example and Comparative Example and a specimen prepared therefrom were tested in the following manner.

(1) Melt index

It was measured with a load of 2.16 kg at 230°C according to ASTM D1238.

(2) Melting temperature (℃)

Using TA Instrument Q2000 differential scanning calorimetry (DSC), the sample was maintained isothermal at 200°C for 10 minutes to remove the thermal history, and then cooled from 200°C to 30°C at a rate of 10°C per minute to crystallize the same thermal history. , and then maintained isothermal at 30° C. for 10 minutes, and then the temperature was again raised by 10° C. per minute to obtain a melting temperature (Tm) from the peak temperature.

(3) polydispersity index

Using a TA Instrument ARES G2 rheometer, the storage modulus (G') and loss modulus (G'') were obtained under a temperature of 200 °C through a dynamic frequency sweep method. did The modulus of the crossover point of these two curves was taken as Gc. From the obtained Gc value, a polydispersity index (PI) value was calculated through Equation 1 below.

[Equation 1]

Polydispersity Index (PI) = 10 ⁶ /Gc

(4) ethylene content

Ethylene content was measured using the characteristic peaks of 720 cm ^-1 and 730 cm ^-1 using infrared absorption spectrum (FT-IR).

(5) solvent extract content

The polypropylene resin was dissolved in xylene at a concentration of 1% by weight at 140° C. for 1 hour, and then measured from the extracted weight after 2 hours at room temperature.

(6) haze

As a measure for judging transparency, an initial haze was measured by injecting a 1.5 mm sheet according to the method of ASTM D1003, and after aging in an oven at 100° C. for 8 hours, the haze according to the change with time was measured.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 melt index g/10 min 30 49 4 30 5 30 melting temperature ℃ 150 144 138 166 127 150 polydispersity index - 3.9 3.8 3.9 3.9 4.0 3.8 Ethylene content weight% 2.7 3.6 5.2 0 9 4.7 Solvent extract content weight% 3.8 6.1 9 2 17 3.9 solvent extract vs.
Ethylene content ratio - 1.4 1.7 1.7 - 1.9 0.8 initial haze % 13 10 8 22 8 30 Haze after aging % 21 17 15 32 18 50 Haze after aging
rate of increase % 62 70 88 45 125 67

Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 melt index g/10 min 30 48 0.5 120 3 30 melting temperature ℃ 149 123 144 145 136 150 polydispersity index - 3.9 3.8 4.0 3.8 1.5 7.0 Ethylene content weight% 2.8 3.6 3.6 3.6 5.2 2.7 Solvent extract content weight% 6 8.7 6.2 6.5 9 4.5 solvent extract vs.
Ethylene content ratio - 2.1 2.4 1.7 1.8 1.7 1.7 initial haze % 14 10 poor machining 18 Haze after aging % 33 21 21 Haze after aging
rate of increase % 136 110 62

As can be seen from Tables 1 and 2 above, when Examples 1 to 3 and Comparative Example 1 are compared, it can be seen that the higher the ethylene content, the lower the haze of the resin composition improves transparency.

However, as in Comparative Example 2, when the ethylene content exceeds the range of the present invention, it can be seen that the melting temperature is too low, the heat resistance of the resin composition is lowered, and the haze increase rate after aging is high.

In Comparative Example 3, since the ratio of the solvent extract to the ethylene content is less than 1, the initial haze is high, and the effect of improving the transparency of the resin composition by adding ethylene is insignificant.

In Comparative Examples 4 and 5, it can be seen that the ratio of the solvent extract to the ethylene content is too high, so that the initial haze is low, but the haze increase rate after aging is very high.

In the case of Comparative Example 6, since the melt index was less than 1, the viscosity of the resin composition was high, and processing was not performed properly due to a high load during processing. In the case of Comparative Example 7, the melt index exceeded 100 and the viscosity was too low, so that it was difficult to pelletize the resin composition, and there was a phenomenon in which aggregation of the resin composition was not performed properly.

In the case of Comparative Example 8, the polydispersity index was less than 2.5, and the melt fracture occurred during processing, so processing was not performed properly. In the case of Comparative Example 9, the polydispersity index was higher than 5.0, and the initial haze was higher than that of Examples 1 to 3, and the transparency was inferior.

The polypropylene resin composition according to the embodiment belonging to the scope of the present invention has excellent transparency, has little transparency deterioration during high temperature or long-term storage, and has an excellent balance with heat resistance. Therefore, the polypropylene resin composition of the present invention can be used in various ways as a material for films, pipes, automobile interior/exterior parts, home appliance parts, and construction/industrial materials.

Claims (10)

A polypropylene resin composition comprising a crystalline ethylene-propylene random copolymer resin, wherein the ratio of the solvent extract content to the ethylene content in the crystalline ethylene-propylene random copolymer resin on a weight % basis is 1.0 to 1.8.
The polypropylene resin composition according to claim 1, wherein the solvent extract content in the crystalline ethylene-propylene random copolymer resin is 1.0 to 12.5 wt%, and the ethylene content is 1.0 to 7.0 wt%.
The polypropylene resin composition according to claim 1, wherein the melt index of the crystalline ethylene-propylene random copolymer resin when measured at 230°C under a load of 2.16 kg is 1 to 100 g/10.
The polypropylene resin composition according to claim 1, wherein the polydispersity index (PI) of the crystalline ethylene-propylene random copolymer resin is 2.5 to 5.0 as measured by an oscillatory shear test method.
The polypropylene resin composition according to claim 1, wherein the melting temperature of the crystalline ethylene-propylene random copolymer is 130°C or higher.
The method according to claim 1, further comprising one or more additives selected from the group consisting of antioxidants, neutralizers, antiblocking agents, reinforcing materials, fillers, weathering stabilizers, antistatic agents, lubricants, slip agents, nucleating agents, flame retardants, pigments and dyes. a polypropylene resin composition.
The method of claim 6, based on 100 parts by weight of the polypropylene resin composition, tetrakis (methylene (3,5-di-t-butyl-4-hydroxy) hydrosilylate), 1,3,5-trimethyl-tris 0.05 to 0.2 parts by weight of at least one antioxidant selected from the group consisting of (3,5-di-t-butyl-4-hydroxybenzene) and tris(2,4-di-t-butylphenyl)phosphite A polypropylene resin composition further comprising the content.
7. The method of claim 6, based on 100 parts by weight of the polypropylene resin composition, dibenzylidene sorbitol, dimethylbenzylidene sorbitol, 1,3:2,4-bis(3,4-dimethylloven) Zylideno)sorbitol (1,3:2,4-bis(3,4-dimethylobenzylideno)sorbitol) and 1,2,3-tridesoxy-4,6:5,7-bis-O-[(4- One or more nucleating agents selected from the group consisting of propylphenyl) methylidene] nonitol (1,2,3-tridesoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]nonitol) A polypropylene resin composition further comprising 0.01 to 1 part by weight.
A polypropylene resin molded article manufactured by molding the polypropylene resin composition according to any one of claims 1 to 8.
The polypropylene resin molded article according to claim 9, wherein the polypropylene resin molded article is selected from the group consisting of films, pipes, electric wires, automobile interior/exterior parts, parts of home appliances, and construction/industrial materials.