KR102494537B1 - Polypropylene resin composition, manufacturing method of the same, and measuring method of rheological properties of the polypropylene resin composition - Google Patents

Abstract

The present invention relates to a polypropylene resin composition, a method for preparing the same, and a method for measuring rheological properties of the polypropylene resin composition, and more particularly, the polypropylene resin composition of the present invention is composed of a propylene monomer and a solid complex without adding a separate modifier. Titanium catalyst, organoaluminum co-catalyst, electron donor and hydrogen gas are mixed, but the injection amount of hydrogen gas is adjusted to prepare a polypropylene resin composition, thereby maintaining excellent stiffness as it is due to their synergistic effect, while significantly improving impact resistance and elongation. can improve
In addition, the method for measuring the rheological properties of the polypropylene resin composition of the present invention can infer the molecular weight and molecular weight distribution of the polypropylene resin by evaluating the rheological properties of the polymer using the cross modulus and cross frequency, which are the points where the storage modulus and the loss modulus meet. At the same time, it can be used as an index to evaluate mechanical properties suitable for application for injection or extrusion.

Description

Polypropylene resin composition, manufacturing method of the same, and measuring method of rheological properties of the polypropylene resin composition}

The present invention relates to a polypropylene resin composition, a method for preparing the same, and a method for measuring rheological properties of the polypropylene resin composition.

In general, crystalline polypropylene resin has excellent molding processability and chemical resistance, excellent mechanical properties such as flexural strength and rigidity, and low cost, so it is applied to various purposes such as automobile parts materials, home appliance parts, food containers, and household goods. It is becoming. Existing homo polypropylene has crystalline polypropylene resin characteristics and is used for injection or compounding purposes. However, there is a limit in its application range due to lack of flexibility at room temperature, relatively low impact resistance and high molding shrinkage.

In particular, in recent years, the use of polypropylene-applied products has been expanding from simple external finishing materials or packaging materials to areas where durability must be guaranteed according to the user's usage environment, and efforts to reduce product thickness to reduce product weight have been made. It is being tried. However, as the product becomes thinner, it has the disadvantage of being easily broken by external impact, so a higher level of impact resistance and elongation are required along with high rigidity.

In order to improve the impact resistance and stretchability of the polypropylene homopolymer, a method of polymerizing an ethylene propylene copolymer in a subsequent reactor after polymerization of polypropylene homopolymer, a method of preparing by adding rubber or elastomers having excellent impact modification effect, or two of these A combination of several methods is being used.

However, these methods have a disadvantage in that rigidity rapidly decreases as the content of the modifier added to the polypropylene homopolymer increases, and the method of adding a rubber-elastomer has a disadvantage in that manufacturing cost increases. In addition, rubber-elastomers effective for improving impact resistance have a disadvantage in that processability during injection molding deteriorates as they are added to polypropylene due to their high viscosity.

On the other hand, the mechanical properties of polypropylene are greatly affected by the length of the polymer chain, that is, the molecular weight, and when the viscosity greatly increases in proportion to the molecular weight, the processability is lowered. Accordingly, when producing a product using polypropylene, there is a problem in that processability is lowered due to an increase in viscosity due to an increase in molecular weight rather than an increase in mechanical properties due to an increase in molecular weight. The processability of polypropylene is greatly influenced not only by the molecular weight but also by the molecular weight distribution of the polypropylene. Accordingly, since it is important to maintain a well-balanced increase in mechanical properties and processability through an increase in molecular weight during the production of polypropylene, a method for evaluating mechanical properties by measuring the rheological properties of polypropylene is required.

Korean Patent Publication No. 2013-0140783

In order to solve the above problems, an object of the present invention is to provide a method for producing a polypropylene resin composition applicable for injection or extrusion.

In addition, an object of the present invention is to provide a polypropylene resin composition with remarkably improved impact resistance and stretchability while maintaining excellent rigidity.

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

Another object of the present invention is to provide a method for measuring rheological properties of a polypropylene resin composition.

The present invention comprises the steps of preparing a mixture by introducing a propylene monomer, a solid titanium complex catalyst, an organic aluminum co-catalyst and an electron donor into a reactor and then injecting hydrogen gas; And polymerizing the mixture to prepare a polypropylene resin composition; including, wherein the polypropylene resin composition has a cross modulus (Gc) value and a cross frequency (Wc) value in the frequency range of 0.1 to 300 1/S as follows Provided is a method for producing a polypropylene resin composition that satisfies the conditions of Formulas 1 and 2.

[Formula 1]

26,000 MPa ≤ Cross Modulus (Gc) ≤ 28,000 MPa

[Formula 2]

60 1/S ≤ crossover frequency (Wc) ≤ 80 1/S

In addition, the present invention relates to a polypropylene resin composition having a melt index (MI) of 5 to 30 g / 10 min (230 ° C, 2.16 kg load), the polypropylene resin composition has a frequency range of 0.1 to 300 1 / S Provides a polypropylene resin composition whose cross modulus (Gc) value and cross frequency (Wc) value satisfy the conditions of formulas 1 and 2 below.

[Formula 1]

26,000 MPa ≤ Cross Modulus (Gc) ≤ 28,000 MPa

[Formula 2]

60 1/S ≤ crossover frequency (Wc) ≤ 80 1/S

In addition, the present invention provides a molded article made of the polypropylene resin composition.

In addition, the present invention comprises the steps of measuring the storage modulus (G ') value and the loss modulus (G ") value according to the frequency for the polypropylene resin composition sample; Deriving a cross modulus (Gc) value and a cross frequency (Wc) value of the polypropylene resin composition sample by Equation 1 below; and evaluating rheological properties such that the cross modulus (Gc) value and the cross frequency (Wc) value of the polypropylene resin composition sample satisfy the conditions of Formulas 1 and 2 below. Provides a measurement method.

[Equation 1]

(In Equation 1, G′ is the storage modulus, G″ is the loss modulus, W is the frequency, Gc is the cross modulus, and Wc is the cross frequency.)

[Formula 1]

26,000 MPa ≤ Cross Modulus (Gc) ≤ 28,000 MPa

[Formula 2]

60 1/S ≤ crossover frequency (Wc) ≤ 80 1/S

The polypropylene resin composition according to the present invention mixes propylene monomer, solid complex titanium catalyst, organic aluminum co-catalyst, electron donor and hydrogen gas without adding a separate modifier, while controlling the reaction temperature, reaction time, and injection amount of hydrogen gas By preparing a polypropylene resin composition, it is possible to remarkably improve impact resistance and elongation while maintaining excellent rigidity by their synergistic effect.

In addition, the method for measuring the rheological properties of the polypropylene resin composition according to the present invention can infer the molecular weight and molecular weight distribution of the polypropylene resin by evaluating the rheological properties of the polymer using the cross modulus and cross frequency, which are the points where the storage modulus and the loss modulus meet. At the same time, it can be used as an index for evaluating mechanical properties suitable for application for injection or extrusion.

The effects of the present invention are not limited to the effects mentioned above. It should be understood that the effects of the present invention include all effects that can be inferred from the following description.

1 is a graph showing the correlation between flexural modulus and toughness for each polypropylene resin composition prepared in Examples 1 and 2 and Comparative Examples 1 to 6.
2 is a graph showing the storage modulus/loss modulus-shear strain curve for Example 1.
Figure 3 is a graph showing the toughness according to the cross modulus for each polypropylene resin composition prepared in Examples 1 and 2 and Comparative Examples 1 to 6.
4 is a graph showing the flexural modulus according to the crossover frequency for each polypropylene resin composition prepared in Examples 1 and 2 and Comparative Examples 1 to 6.

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

The present invention relates to a polypropylene resin composition, a method for preparing the same, and a method for measuring rheological properties of the polypropylene resin composition.

Existing polypropylene resins have disadvantages in that their application range is limited due to lack of flexibility at room temperature, relatively low impact resistance and high molding shrinkage. In particular, as the use of products to which polypropylene is applied is diversified, as the products become thinner, they are easily broken by external impact, and thus high impact resistance and elongation are required.

Therefore, in the present invention, the polypropylene resin composition according to the present invention is mixed with propylene monomer, solid complex titanium catalyst, organoaluminum cocatalyst, electron donor and hydrogen gas without adding a separate modifier, but reaction temperature, reaction time, hydrogen gas By adjusting the injection amount of the polypropylene resin composition to prepare, it is possible to remarkably improve the impact resistance and elongation while maintaining excellent stiffness by their synergistic effect.

Specifically, the present invention comprises the steps of preparing a mixture by introducing a propylene monomer, a solid titanium complex catalyst, an organic aluminum co-catalyst and an electron donor into a reactor and then injecting hydrogen gas; And polymerizing the mixture to prepare a polypropylene resin composition; including, wherein the polypropylene resin composition has a cross modulus (Gc) value and a cross frequency (Wc) value in the frequency range of 0.1 to 300 1/S as follows Provided is a method for producing a polypropylene resin composition that satisfies the conditions of Formulas 1 and 2.

[Formula 1]

26,000 MPa ≤ Cross Modulus (Gc) ≤ 28,000 MPa

[Formula 2]

60 1/S ≤ crossover frequency (Wc) ≤ 80 1/S

The solid titanium complex catalyst may use a compound produced by supporting TiCl ₃ or TiCl ₄ on a MgCl ₂ carrier, and preferably a compound in which TiCl ₃ is supported on a MgCl ₂ carrier.

The solid titanium complex catalyst may contain 0.0003 to 0.005 parts by weight, preferably 0.0006 to 0.002 parts by weight, more preferably 0.0008 to 0.0015 parts by weight, and most preferably 0.0009 to 0.001 parts by weight, based on 100 parts by weight of the propylene monomer. can At this time, if the content of the solid titanium complex catalyst is less than 0.0003 parts by weight, the polymerization reaction may not be smoothly performed because thermal energy for the polymerization reaction is not sufficiently supplied. Conversely, if it exceeds 0.005 parts by weight, the solid titanium complex catalyst is excessive There is a problem that the temperature control is impossible because the polymerization reaction proceeds violently due to the input.

An alkyl aluminum compound was used as the organic aluminum co-catalyst, and for example, at least one selected from the group consisting of triethyl aluminum, diethyl chloro aluminum, tributyl aluminum, trisisobutyl aluminum, and trioctyl aluminum, but in the present invention not particularly limited Preferably it may be triethylaluminum.

The organoaluminum cocatalyst may be included in a concentration of 1 to 10 mmol, preferably 2 to 8 mmol, more preferably 3 to 6 mmol, and most preferably 4.2 to 4.6 mmol, based on the total amount of the mixture.

The electron donor is an organic silane compound, for example, diphenyldimethoxysilane, phenyltrimethoxysilane, phenylethyldimethoxysilane, phenylmethyldimethoxysilane, methoxytrimethylsilane, isobutyltrimethoxysilane, diiso At least one selected from the group consisting of butyldimethoxysilane, diisopropyldimethoxysilane, di-t-butyldimethoxysilane, dicyclopentyldimethoxysilane, cyclohexylmethyldimethoxysilane, and dicyclohexyldimethoxysilane. However, it is not particularly limited in the present invention. Preferably, it may be cyclohexylmethyldimethoxysilane.

The electron donor may be included in a concentration of 0.05 to 10 mmol, preferably 0.1 to 6 mmol, more preferably 0.2 to 1.5 mmol, and most preferably 0.3 to 0.5 mmol, based on the total amount of the mixture.

The molar ratio of the electron donor/organoaluminum cocatalyst may be 0.02 to 1, preferably 0.08 to 0.7, and most preferably 0.1 to 0.2. In particular, when the molar ratio is less than 0.02, the crystallinity may be lowered due to low stereoregularity, and the rigidity may not be maintained excellently. Conversely, if the molar ratio exceeds 1, the electron donor may be added in an excessive amount, and thus the polymerization reaction may not proceed properly due to the influence of impurities in the electron donor.

The hydrogen gas may be injected at a pressure of 1.40 to 2.25 bar, preferably 1.50 to 2.10 bar, and most preferably 1.68 to 1.83 bar. At this time, if the injection amount of the hydrogen gas is less than 1.40 bar, the weight average molecular weight of the polypropylene resin composition may be excessively increased, resulting in deterioration in fluidity during extrusion processing. Conversely, if the injection amount of the hydrogen gas is greater than 2.25 bar, the polypropylene resin composition may have too small a weight average molecular weight, resulting in deterioration in stretchability.

In preparing the polypropylene resin composition, polymerization may be performed at a temperature of 62 to 78 °C and a pressure of 2 to 5 MPa for 60 to 180 minutes. Preferably at a temperature of 65 to 75 °C and a pressure of 2.5 to 4.5 MPa for 100 to 150 minutes, most preferably at a temperature of 68 to 72 °C and a pressure of 3 to 4 MPa for 110 to 130 minutes. At this time, if the reaction temperature is less than 62 ° C., the polymerization reaction may not be performed properly because the heat energy required for the polymerization reaction is not sufficiently supplied. Conversely, if it exceeds 78 ° C. chunk) may occur. In addition, when the reaction time is out of the range, it may be difficult to obtain a polypropylene resin composition having a melt index within a specific range desired in the present invention due to insufficient polymerization or excessive polymerization of the polypropylene resin.

The polypropylene resin composition may be a homopolypropylene resin, and has a melt index (MI) of 5 to 30 g/10min, preferably 7 to 18 g/10min, and most preferably 9 to 13 g/10min. (230 °C, 2.16 kg load). In addition, the polypropylene resin composition may have a weight average molecular weight of 250,000 to 450,000 g/mol and a molecular weight distribution of 3.0 to 5.0 suitable for application for injection or extrusion.

The polypropylene resin composition may have a cross modulus (Gc) value and a cross frequency (Wc) value in the frequency range of 0.1 to 300 1/S that satisfy the conditions of Formulas 1 and 2 below.

[Formula 1]

26,000 MPa ≤ Cross Modulus (Gc) ≤ 28,000 MPa

[Formula 2]

60 1/S ≤ crossover frequency (Wc) ≤ 80 1/S

The cross modulus means the modulus of the point where the storage modulus and the loss modulus cross, and the crossover frequency means the frequency of the point where the storage modulus and the loss modulus cross. The higher the value of the cross modulus, the narrower the molecular weight distribution, and the smaller the value, the wider the molecular distribution. In addition, the higher the value of the crossover frequency, the lower the molecular weight, and the smaller the value, the higher the molecular weight.

The crossover modulus is related to the molecular weight distribution of the polymer, and the crossover frequency may have a correlation with the molecular weight of the polymer. The cross modulus and the cross frequency are mutually dependent, and simple movement between up and down and left and right is rare, and can mainly move in a diagonal direction (upper right, lower left, etc.). Accordingly, the method for measuring rheological properties can be used as an indicator of the complex effect of the two elements, since it is difficult to independently present the molecular weight and molecular weight distribution of the polypropylene resin composition, and is applied to evaluate mechanical properties such as flexural modulus and toughness. can do.

The cross modulus of the general formula 1 is a preferable cross modulus value (26,000 to 28,000 MPa), more preferably 26,500 to 27,500 MPa, when the reference point of toughness advantageous in extrusion processing is set to the usual range of 190,000 N / mm can

The crossover frequency of Formula 2 is a preferred crossover frequency value (60 to 80 1/S), more preferably 65 to 70 1, when the reference point of the flexural modulus, which is advantageous during injection processing, is set to 1,550 MPa, which is a typical range. It can be /S.

However, when the polypropylene resin composition satisfies only one or both of the conditions of Formulas 1 and 2, it is difficult to infer the molecular weight and molecular weight distribution of the polypropylene resin composition, and the flexural modulus is lowered or the toughness is reduced. This is rapidly degraded, and there is a problem that these mechanical properties cannot be maintained in balance. As a result, it may be difficult to apply the polypropylene resin composition to injection and extrusion applications.

In particular, although not explicitly described in the following Examples or Comparative Examples, the polypropylene resin composition according to the present invention is obtained by preparing a polypropylene resin sample by varying the following 10 conditions, and then performing cross modulus and cross modulus by a conventional method. The physical properties of frequency, impact resistance, dimensional stability and heat resistance were evaluated.

As a result, unlike in other conditions and other numerical ranges, when all of the following conditions are satisfied, both the cross modulus and cross frequency ranges are satisfied, and the physical properties of excellent impact resistance, dimensional stability and heat resistance are all uniformly excellent. Confirmed.

① the solid titanium complex catalyst is a compound in which TiCl ₃ is supported on a MgCl ₂ carrier, ② the solid titanium complex catalyst contains 0.0009 to 0.001 part by weight based on 100 parts by weight of the propylene monomer, ③ the organic aluminum co-catalyst is tri ethyl aluminum, ④ the organoaluminum cocatalyst is included in a concentration of 4.2 to 4.6 mmol based on the total amount of the mixture, ⑤ the electron donor is cyclohexylmethyldimethoxy silane, and ⑥ the electron donor is included in the total amount of the mixture 0.3 to 0.5 mmol, ⑦ the electron donor/organoaluminum cocatalyst molar ratio is 0.1 to 0.2, ⑧ the hydrogen gas is injected at a pressure of 1.68 to 1.83 bar, ⑨ the polypropylene resin composition The preparation step is polymerization at a temperature of 68 to 72 ° C. and a pressure of 3 to 4 MPa for 110 to 130 minutes, ⑩ the polypropylene resin composition has a melt index (MI) of 9 to 13 g / 10 min (230 °C, 2.16 kg load).

However, if any one of the above 10 conditions is not satisfied, only one of the cross modulus or cross frequency range is satisfied, but both are not satisfied, and the heat resistance is significantly lowered, or the impact resistance and dimensional stability are not satisfied. All of them did not show evenly excellent physical properties.

On the other hand, in the present invention, for a polypropylene resin composition having a melt index (MI) of 5 to 30 g/10 min (230 ° C., 2.16 kg load), the polypropylene resin composition has a frequency of 0.1 to 300 1/S It provides a polypropylene resin composition whose cross modulus (Gc) value and cross frequency (Wc) value satisfy the conditions of formulas 1 and 2 below.

[Formula 1]

26,000 MPa ≤ Cross Modulus (Gc) ≤ 28,000 MPa

[Formula 2]

60 1/S ≤ crossover frequency (Wc) ≤ 80 1/S

In addition, the present invention provides a molded article made of the polypropylene resin composition.

The molded article may be a molded article for injection molding or extrusion molding.

In addition, the present invention comprises the steps of measuring the storage modulus (G') value and the loss modulus (G″) value according to the frequency for the polypropylene resin composition sample; Deriving a cross modulus (Gc) value and a cross frequency (Wc) value of the polypropylene resin composition sample by Equation 1 below; and evaluating rheological properties such that the cross modulus (Gc) value and the cross frequency (Wc) value of the polypropylene resin composition sample satisfy the conditions of Formulas 1 and 2 below. Provides a measurement method.

[Equation 1]

(In Equation 1, G′ is the storage modulus, G″ is the loss modulus, W is the frequency, Gc is the cross modulus, and Wc is the cross frequency.)

[Formula 1]

26,000 MPa ≤ Cross Modulus (Gc) ≤ 28,000 MPa

[Formula 2]

60 1/S ≤ crossover frequency (Wc) ≤ 80 1/S

Existing polypropylene products independently judge molecular weight and molecular weight distribution to present each required physical property value, but there is a problem in that it is difficult to independently determine the two factors in practical product development. In the dynamic shear strain of the polymer, it is used as a desirable index for practical polypropylene products because it can confirm the mutually dependent effect between the molecular weight and molecular weight distribution of the polymer without judging the two factors independently.

The method for measuring rheological properties of the present invention measures the storage modulus (G′) value and the loss modulus (G″) value according to frequency with respect to the polypropylene resin composition, respectively, and then crosses the point where the two moduli meet by Equation 1 above. Modulus and crossover frequency values can be derived. In this case, the rheological property may be modulus. The storage modulus and loss modulus may be measured by applying periodic strain to the polymer sample, and a method of applying periodic strain to the polymer sample is not particularly limited and may be applied using vertical vibration or rotational vibration. The frequency and strain rate of the cyclic strain may vary in various ways depending on the type of polymer sample used, the type of cyclic strain applied to the polymer sample, or the temperature of the polymer sample. The temperature condition is not particularly limited and may be appropriately changed depending on the type of polymer sample used or the type of cyclic strain applied to the polymer sample.

The cross modulus means the modulus of the point where the storage modulus and the loss modulus cross, and the crossover frequency means the frequency of the point where the storage modulus and the loss modulus cross. The higher the value of the cross modulus, the narrower the molecular weight distribution, and the smaller the value, the wider the molecular distribution. In addition, the higher the value of the crossover frequency, the lower the molecular weight, and the smaller the value, the higher the molecular weight.

The crossover modulus is related to the molecular weight distribution of the polymer, and the crossover frequency may have a correlation with the molecular weight of the polymer. The cross modulus and the cross frequency are mutually dependent, and simple movement between up and down and left and right is rare, and can mainly move in a diagonal direction (upper right, lower left, etc.). Accordingly, the method for measuring rheological properties can be used as an indicator of the complex effect of the two elements, since it is difficult to independently present the molecular weight and molecular weight distribution of the polypropylene resin composition, and is applied to evaluate mechanical properties such as flexural modulus and toughness. can do.

That is, since the storage modulus and the loss modulus are affected by the molecular weight and molecular weight distribution of the polymer, the molecular weight and molecular weight distribution of the polymer are evaluated by evaluating the rheological properties of the polymer measured through the cross modulus and the cross frequency, which are the points where these two moduli meet. It can be inferred, and furthermore, it can be presented as an index for evaluating the mechanical properties of flexural modulus and toughness suitable for injection or extrusion.

The range of the frequency may be 0.1 to 300 1/S, preferably 1 to 150 1/S.

The polypropylene resin composition has a melt index (MI) of 5 to 30 g/10 min, preferably 7 to 18 g/10 min, and most preferably 9 to 13 g/10 min (230 °C, 2.16 kg load) can be

As described above, the method for measuring the rheological properties of the polypropylene resin composition according to the present invention evaluates the rheological properties of the polymer using the cross modulus and the cross frequency, which are the points where the storage modulus and the loss modulus meet, thereby evaluating the molecular weight and molecular weight distribution of the polypropylene resin. can be inferred, and at the same time it can be used as an index to evaluate mechanical properties suitable for application for injection or extrusion.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited by the following examples.

Example 1

A 3L stainless steel reactor was vacuum-dried at 70 ° C. and then cooled to 10 ° C. or less, and 0.00097 parts by weight of a compound in which TiCl ₃ was supported on a solid complex titanium catalyst MgCl ₂ carrier was added to 100 parts by weight (770 g) of propylene monomer in the reactor. 7.5 mg) was added, followed by 4.4 mmol of triethylaluminum (TEAl) as an organic aluminum cocatalyst and 0.44 mmol of cyclohexylmethyldimethoxysilane as an external electron donor, and then 1.68 bar of hydrogen gas was injected. At this time, the injected amount of hydrogen gas was adjusted so that the melt index of homo polypropylene was 9 to 13 g/10 min. Thereafter, the temperature of the reactor was raised to 70 °C, and polymerization was performed for 120 minutes under a reaction pressure of 3.0 to 4.0 MPa to obtain a homopolypropylene resin composition. Then, after polymerization of homo polypropylene was completed, unreacted propylene was vented.

Example 2

The polymerization reaction was carried out at a reaction temperature of 70 ° C. for 75 minutes, except that the injection amount of hydrogen gas injected into the reactor was injected at 1.83 bar so that polypropylene having the same melt index range as in Example 1 was polymerized at the reaction temperature. Then, a polypropylene resin composition was prepared in the same manner as in Example 1.

Comparative Example 1

The polymerization reaction was carried out at a reaction temperature of 60 ° C. for 75 minutes, except that the injection amount of hydrogen gas injected into the reactor was injected at 2.31 bar so that polypropylene in the same melt index range as in Example 1 was polymerized at the reaction temperature. Then, a polypropylene resin composition was prepared in the same manner as in Example 1.

Comparative Example 2

The polymerization reaction was carried out at a reaction temperature of 80 ° C. for 75 minutes, except that the injection amount of hydrogen gas injected into the reactor was injected at 1.35 bar so that polypropylene having the same melt index range as in Example 1 was polymerized at the reaction temperature. Then, a polypropylene resin composition was prepared in the same manner as in Example 1.

Comparative Example 3

A commercially available homopolypropylene resin composition from company A was purchased and used. Melt Index, MWD, crystallization temperature and melting temperature measurement results are shown in Table 1 below.

Comparative Example 4

A commercially available homopolypropylene resin composition from B company was purchased and used. Melt Index, MWD, crystallization temperature and melting temperature measurement results are shown in Table 1 below.

Comparative Example 5

A commercially available homopolypropylene resin composition from C company was purchased and used. Melt Index, MWD, crystallization temperature and melting temperature measurement results are shown in Table 1 below.

Comparative Example 6

A commercially available homopolypropylene resin composition from D company was purchased and used. Melt Index, MWD, crystallization temperature and melting temperature measurement results are shown in Table 1 below.

division melt index
(g/10min) molecular weight distribution
(Mw/Mn) crystallization temperature
(℃) melting temperature
(℃) Comparative Example 3 9.8 4.57 121.5 164.3 Comparative Example 4 12.7 4.48 117.5 162.0 Comparative Example 5 13.1 4.23 120.9 164.1 Comparative Example 6 11.2 3.54 112.9 161.2

Experimental Example 1

After preparing specimens by a conventional method using each of the polypropylene resin compositions prepared in Examples 1 and 2 and Comparative Examples 1 to 6, physical properties were measured by the following physical property evaluation method. The results are shown in Table 2 below.

[Physical property evaluation method]

(1) Melt flow index (MI): measured according to ASTM D1238.

(2) Tc and Tm analysis: measured under primary cooling and secondary heating conditions at a rate of 10 °C/min under a nitrogen atmosphere using a DSC device.

(3) Flexural strength: measured according to the ASTM D790 method.

(4) Izod impact strength: measured according to ASTM D256.

(5) Toughness: In the tensile strength graph (strain vs. stress) measured according to ASTM D 638, the area under the stress graph was calculated.

(6) Dynamic modulus of elasticity of polymer: storage modulus (G′) value and loss modulus (G ″) values were measured, and then the cross modulus G _C and cross frequency W _C were defined and calculated from the dynamic-shear strain curve obtained as follows.

[Equation 1]

(In Equation 1, G′ is the storage modulus, G″ is the loss modulus, W is the frequency, Gc is the cross modulus, and Wc is the cross frequency.)

division curve
elastic modulus Izod impact strength Elongation at break tenacity cross
modulus cross
frequency unit MPa J/m % N/m Pa 1/s Example 1 1,600 15.1 390 367,236 27,572.4 68.62 Example 2 1,580 15.0 461 195,856 26,709.1 66.15 Comparative Example 1 1,630 15.0 123 149,716 25,758.3 63.19 Comparative Example 2 1,700 16.0 10 15,127 28,762.5 84.47 Comparative Example 3 1,700 15.0 25 28,445 22,420.8 41.55 Comparative Example 4 1,600 15.0 199 145,528 22,393.1 60.29 Comparative Example 5 1,580 15.9 128 153,442 23,051.6 61.44 Comparative Example 6 1,480 14.6 490 459,406 29,615.8 82.10

According to the results of Table 2, in the case of Examples 1 and 2, compared to Comparative Examples 1 to 6, the flexural modulus, impact strength, elongation at break and toughness were uniformly superior in mechanical properties, and thus applied to injection or extrusion applications. It was confirmed that it is suitable for In particular, it was confirmed that it exhibited a very high elongation at break, excellent stretchability, and exhibited physical properties that were resistant to breakage with respect to stretching.

On the other hand, in the case of Comparative Examples 1 to 5, the impact strength was generally excellent, but the elongation at break was generally low, and in particular, in the case of Comparative Examples 2 and 3, the toughness was the lowest. In addition, in the case of Comparative Example 6, it was found that it exhibited the best elongation and toughness and was suitable for extrusion use, but it was not preferable for injection use due to its low stiffness.

Experimental Example 2

The correlation between flexural modulus and toughness and storage modulus/loss modulus-shear strain were evaluated for each of the polypropylene resin compositions prepared in Examples 1 and 2 and Comparative Examples 1 to 6. The results are shown in Figures 1 and 2.

1 is a graph showing the correlation between flexural modulus and toughness for each polypropylene resin composition prepared in Examples 1 and 2 and Comparative Examples 1 to 6. Referring to FIG. 1, it can be seen that the flexural modulus and toughness are inversely proportional to each other. In particular, a high flexural modulus (1,550 MPa or more) is generally required for injection applications, and high toughness (190,000 N/mm or more) is required for extrusion applications. In the case of Examples 1 and 2, injection applications And it was found that all of the mechanical properties for extrusion were satisfied. On the other hand, in the case of Comparative Examples 1 to 6, it was confirmed that both physical properties were not satisfied.

2 is a graph showing the storage modulus/loss modulus-shear strain curve for Example 1. Referring to FIG. 2, the modulus at the point where the storage modulus (upper) and the loss modulus (lower) intersect was identified as the cross modulus, and the frequency at the point where they intersect was identified as the crossover frequency. A higher value of the cross modulus means a narrower molecular weight distribution, and a smaller value means a wider molecular weight distribution. In addition, the larger the value of the crossover frequency, the lower the molecular weight, and the smaller the value, the higher the molecular weight.

Experimental Example 3

Flexural modulus and toughness according to cross modulus and cross frequency were evaluated for each of the polypropylene resin compositions prepared in Examples 1 and 2 and Comparative Examples 1 to 6. The results are shown in Figures 3 and 4.

Figure 3 is a graph showing the toughness according to the cross modulus for each polypropylene resin composition prepared in Examples 1 and 2 and Comparative Examples 1 to 6. According to the results of FIG. 3 , it was confirmed that the toughness increased as the cross modulus increased in the measurement results except for Comparative Example 2. In particular, it was found that Examples 1 and 2 satisfy the preferred range of cross modulus values (26,000 to 28,000 MPa) when the reference point advantageous during extrusion is set to the usual range of 190,000 N/mm. Through this, it was confirmed that Examples 1 and 2 had toughness suitable for extrusion processing.

4 is a graph showing the flexural modulus according to the crossover frequency for each polypropylene resin composition prepared in Examples 1 and 2 and Comparative Examples 1 to 6. According to the results of FIG. 4, in the measurement results except for Comparative Example 2, it was confirmed that the flexural modulus decreased as the crossover frequency increased. In particular, it was found that Examples 1 and 2 satisfies the preferred range of crossover frequency values (60 to 80 1/S) when the reference point advantageous during injection processing is set to 1,550 MPa, which is a typical range. Through this, it was confirmed that Examples 1 and 2 had a flexural modulus suitable for injection processing.

Overall, in the case of Examples 1 and 2, it was found that the flexural modulus (stiffness) and toughness were balanced with each other to have excellent physical properties, so that they could be applied to molded articles for injection and extrusion purposes.

Claims (18)

preparing a mixture by introducing a propylene monomer, a solid titanium complex catalyst, an organoaluminum cocatalyst, and an electron donor into a reactor and then injecting hydrogen gas; and
Polymerizing the mixture to prepare a polypropylene resin composition; Including,
The polypropylene resin composition has a cross modulus (Gc) value and a cross frequency (Wc) value in the frequency range of 0.1 to 300 1/S and satisfies the conditions of the following general formulas 1 and 2,
The hydrogen gas is injected at a pressure of 1.40 to 2.25 bar,
The polypropylene resin composition is a homopolypropylene resin, has a weight average molecular weight of 250,000 to 450,000 g / mol, and a molecular weight distribution of 3.0 to 5.0,
The polypropylene resin composition has a melt index (Melt Index, MI) of 5 to 30 g / 10 min (230 ℃, 2.16 kg load) of the method of producing a polypropylene resin composition.
[Formula 1]
26,000 MPa ≤ Cross Modulus (Gc) ≤ 28,000 MPa
[Formula 2]
60 1/S ≤ crossover frequency (Wc) ≤ 80 1/S
According to claim 1,
The solid complex titanium catalyst is a method for producing a polypropylene resin composition that is a compound produced by supporting TiCl ₃ or TiCl ₄ on a MgCl ₂ carrier.
According to claim 1,
The solid complex titanium catalyst is a method for producing a polypropylene resin composition comprising 0.0003 to 0.005 parts by weight based on 100 parts by weight of the propylene monomer.
According to claim 1,
The organoaluminum cocatalyst is at least one selected from the group consisting of triethylaluminum, diethylchloroaluminum, tributylaluminum, trisisobutylaluminum and trioctylaluminum Method for producing a polypropylene resin composition.
According to claim 1,
The organoaluminum co-catalyst is a method for producing a polypropylene resin composition comprising a concentration of 1 to 10 mmol based on the total content of the mixture.
According to claim 1,
The electron donor is diphenyldimethoxysilane, phenyltrimethoxysilane, phenylethyldimethoxysilane, phenylmethyldimethoxysilane, methoxytrimethylsilane, isobutyltrimethoxysilane, diisobutyldimethoxysilane, diisopropyl Method for producing a polypropylene resin composition comprising at least one selected from the group consisting of dimethoxysilane, di-t-butyldimethoxysilane, dicyclopentyldimethoxysilane, cyclohexylmethyldimethoxysilane and dicyclohexyldimethoxysilane .
According to claim 1,
The method for producing a polypropylene resin composition comprising the electron donor in a concentration of 0.05 to 10 mmol based on the total content of the mixture.
According to claim 1,
Method for producing a polypropylene resin composition of the molar ratio of the electron donor / organoaluminum co-catalyst is 0.02 to 1.
delete According to claim 1,
The step of preparing the polypropylene resin composition is a method for producing a polypropylene resin composition of polymerization for 60 to 180 minutes at a temperature of 62 to 78 ℃ and a pressure of 2 to 5 MPa.
delete According to claim 1,
The solid complex titanium catalyst is a compound in which TiCl ₃ is supported on a MgCl ₂ support,
The solid complex titanium catalyst contains 0.0009 to 0.001 parts by weight based on 100 parts by weight of the propylene monomer,
The organoaluminum co-catalyst is triethylaluminum,
The organoaluminum cocatalyst is included in a concentration of 4.2 to 4.6 mmol based on the total content of the mixture,
The electron donor is cyclohexylmethyldimethoxy silane,
The electron donor is included in a concentration of 0.3 to 0.5 mmol based on the total content of the mixture,
The molar ratio of the electron donor/organoaluminum co-catalyst is 0.1 to 0.2,
The hydrogen gas is injected at a pressure of 1.68 to 1.83 bar,
The step of preparing the polypropylene resin composition is polymerization at a temperature of 68 to 72 ° C. and a pressure of 3 to 4 MPa for 110 to 130 minutes,
The polypropylene resin composition has a melt index (Melt Index, MI) of 9 to 13 g / 10 min (230 ℃, 2.16 kg load) of the production method of the polypropylene resin composition.
For a polypropylene resin composition having a melt index (MI) of 5 to 30 g/10 min (230 ° C., 2.16 kg load),
The polypropylene resin composition has a cross modulus (Gc) value and a cross frequency (Wc) value in the frequency range of 0.1 to 300 1/S and satisfies the conditions of the following general formulas 1 and 2,
The polypropylene resin composition is prepared by introducing a propylene monomer, a solid titanium complex catalyst, an organic aluminum cocatalyst, and an electron donor into a reactor, injecting hydrogen gas to form a mixture, and polymerizing the mixture,
The hydrogen gas is injected at a pressure of 1.40 to 2.25 bar,
The polypropylene resin composition is a homopolypropylene resin, a weight average molecular weight of 250,000 to 450,000 g / mol, and a polypropylene resin composition having a molecular weight distribution of 3.0 to 5.0.
[Formula 1]
26,000 MPa ≤ Cross Modulus (Gc) ≤ 28,000 MPa
[Formula 2]
60 1/S ≤ crossover frequency (Wc) ≤ 80 1/S
A molded article made of the polypropylene resin composition of claim 13.
According to claim 14,
The molded article is a molded article for injection molding or extrusion molding.
Measuring a storage modulus (G′) value and a loss modulus (G″) value according to frequency for the polypropylene resin composition sample of claim 13;
Deriving a cross modulus (Gc) value and a cross frequency (Wc) value of the polypropylene resin composition sample by Equation 1 below; and
Evaluating rheological properties such that the cross modulus (Gc) value and the cross frequency (Wc) value of the polypropylene resin composition sample satisfy the conditions of Formulas 1 and 2 below;
Method for measuring rheological properties of a polypropylene resin composition comprising a.
[Equation 1]

(In Equation 1, G′ is the storage modulus, G″ is the loss modulus, W is the frequency, Gc is the cross modulus, and Wc is the cross frequency.)
[Formula 1]
26,000 MPa ≤ Cross Modulus (Gc) ≤ 28,000 MPa
[Formula 2]
60 1/S ≤ crossover frequency (Wc) ≤ 80 1/S
According to claim 16,
The range of the frequency is from 0.1 to 300 1 / S method of measuring the rheological properties of the polypropylene resin composition.
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