KR102539409B1 - Homo polypropylene resin composition having improved xylene solubility and manufacturing method of the same - Google Patents

Abstract

The present invention relates to a homopolypropylene resin composition having improved solubility in xylene and a method for preparing the same, and more particularly, to a propylene monomer, a main catalyst and a cocatalyst, and two types of first donor and second donor are essentially included, , By mixing these donors at a specific concentration and molar ratio, the impact resistance and production yield of the homopolypropylene resin can be remarkably improved by increasing xylene solubility while maintaining polymerization activity and molecular weight distribution high above a certain level. In addition, since the xylene solubility value can be easily adjusted only by mixing the first donor and the second donor, the manufacturing process is simple, and it can be applied to various fields such as products requiring high stiffness or stretchability.

Description

Homo polypropylene resin composition having improved xylene solubility and manufacturing method of the same}

The present invention relates to a homopolypropylene resin composition having improved xylene solubility while maintaining polymerization activity and molecular weight distribution at or above a certain level, and a method for preparing the same.

Polypropylene (PP) is one of the most widely used plastic resins worldwide and is synthesized through polymer polymerization of propylene. Polypropylene is generally prepared by polymerization in the presence of propylene as a monomer, titanium as a main catalyst, organoaluminum as a cocatalyst, hydrogen, and an electron donor, and this is called Homo polypropylene (Homo PP). In addition, when propylene and ethylene are used together as monomers, it is called impact polypropylene. The physical properties of the polymerized homo-polypropylene or impact polypropylene vary greatly depending on the type of main catalyst, the amount of hydrogen injected, the type and amount of donor injected, and the fields of application thereof are also very different.

In particular, factors that can be easily changed to control the physical properties of homopolypropylene in a gas phase or bulk slurry polymerization process include the amount of injected hydrogen and the type and amount of donors. When the amount of hydrogen injected during polymerization is reduced, the polymer chain of polypropylene becomes longer and the viscosity decreases, and when the injected amount of hydrogen is increased, the polymer chain is shortened and the viscosity increases. The donor material affects polymerization activity, stereoregularity, hydrogen reactivity, xylene soluble (XS), etc. of polypropylene through interaction with the transition metal on the catalyst.

Among the various physical properties of homopolypropylene, xylene solubility (XS) value is an important value in determining the application field of homopolypropylene. Polypropylene has an isotactic part in which the chain repeats have a uniform direction and an attack part in which the chain repeats have an irregular direction. The xylene solubility means the ratio of the atactic part in the total polypropylene, and the higher the xylene solubility value, the more the atactic part exists.

A method of adjusting the xylene solubility level under a single main catalyst includes a method of changing the type of donor or changing the injection amount of the donor. However, although the xylene solubility value can be adjusted when the type of donor is changed, it is difficult to specify a desired value, and there is a problem in that a completely different product is produced due to different primary physical properties. In addition, when the injection amount of the donor is changed, the xylene solubility value can be increased or decreased to a certain level, but there is a problem in that the production yield of polypropylene is lowered because the polymerization activity is significantly lowered except at the optimum point. This means lowering productivity in commercial processes, leading to weakening of product's price competitiveness.

Therefore, it is necessary to research and develop a new polypropylene production method capable of improving impact resistance and productivity by selectively increasing only xylene solubility while maintaining the catalytic activity and molecular weight distribution of polypropylene at a certain level or higher.

Korean Patent Registration No. 10-1862917

In order to solve the above problems, an object of the present invention is to provide a method for preparing a homopolypropylene resin composition having increased xylene solubility while maintaining polymerization activity and molecular weight distribution at a high level or higher.

Another object of the present invention is to provide a homopolypropylene resin composition prepared by the above method.

Another object of the present invention is to provide a molded article manufactured using the homopolypropylene resin composition.

The present invention comprises the steps of preparing a mixture by introducing a propylene monomer, a main catalyst, a cocatalyst, a first donor and a second donor into a reactor and then injecting hydrogen gas; and polymerizing the mixture to prepare a homopolypropylene resin composition, wherein the first donor and the second donor are included in a concentration of 0.1 to 10 mmol based on the total amount of the mixture, and the first donor and The molar ratio of the second donor is 1: 0.5 to 3.5, and the homopolypropylene resin composition has a xylene solubility (X/S) of 0.7 to 10% by weight. do.

In addition, the present invention relates to a homopolypropylene resin composition having a melt index (MI) of 0.1 to 200 g/10min (230 °C, 2.16 kg load), the homopolypropylene resin composition has xylene solubility (Xylene Solubility, X/S) is 0.7 to 10% by weight.

In addition, the present invention provides a molded article manufactured using the homopolypropylene resin composition.

The homo polypropylene resin composition according to the present invention essentially includes two types of first and second donors together with a main catalyst and a cocatalyst in a propylene monomer, and by mixing these donors at specific concentrations and molar ratios, polymerization activity and molecular weight are improved. The impact resistance and production yield of the homo-polypropylene resin can be remarkably improved by increasing the solubility of xylene while maintaining the distribution high above a certain level.

In addition, the homopolypropylene resin composition according to the present invention can easily adjust the xylene solubility value by simply mixing the first donor and the second donor, so the manufacturing process is simple, and it is applied to various fields such as products requiring high stiffness or stretchability. There are possible advantages.

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.

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

In the present invention, the first donor and the second donor each mean an external donor, and the internal donor is included in the main catalyst.

The present invention relates to a homopolypropylene resin composition having improved xylene solubility and a method for preparing the same.

As described above, polymerization of polypropylene requires a main catalyst, a co-catalyst, hydrogen, and a donor. The physical properties of polypropylene that are mainly affected by these include polymerization activity, molecular weight distribution (MWD), melt flow rate (MFR), and xylene soluble (XS). In particular, the xylene solubility value of homopolypropylene is an important factor in determining the application field, and when the xylene solubility value is increased, the impact resistance can be improved.

As a method of adjusting the xylene solubility level under a single main catalyst, there is a method of changing the type of donor or changing the injection amount of the donor. However, when the type of donor is changed, although the xylene solubility value can be adjusted, it is difficult to specify a desired value, and even other primary physical properties are changed, resulting in a completely different product. In addition, in order to increase the xylene solubility value, the amount of the donor should be reduced during polymerization, but as the amount of the donor decreases, there is a problem in that the polymerization activity significantly decreases. This means lowering productivity in commercial processes, leading to weakening of product's price competitiveness.

Accordingly, in the present invention, during the polymerization of homo polypropylene, two types of donors are necessarily included, but by mixing them at a specific concentration and molar ratio, the polymerization activity and molecular weight distribution are maintained at a high level and the solubility of xylene is increased to increase homo polypropylene. The impact resistance and production yield of the resin can be remarkably improved. In addition, since the xylene solubility value can be easily adjusted only by mixing the first donor and the second donor, the manufacturing process is simple, and there is an advantage that it can be applied to various fields such as products requiring high stiffness or stretchability.

Specifically, the present invention comprises the steps of preparing a mixture by introducing a propylene monomer, a main catalyst, a cocatalyst, a first donor and a second donor into a reactor and then injecting hydrogen gas; and polymerizing the mixture to prepare a homopolypropylene resin composition, wherein the first donor and the second donor are included in a concentration of 0.1 to 10 mmol based on the total amount of the mixture, and the first donor and The molar ratio of the second donor is 1: 0.5 to 3.5, and the homopolypropylene resin composition has a xylene solubility (X/S) of 0.7 to 10% by weight. do.

The main catalyst may be a 4th generation Ziegler-Natta containing titanium content of 1.5 to 3% by weight, preferably 1.5 to 2.5% by weight, and most preferably 1.5 to 2% by weight. At this time, when the titanium content of the main catalyst is out of the above range, the xylene solubility may slightly increase, but the polymerization activity and the molecular weight distribution may decrease rapidly, resulting in a decrease in the productivity of homopolypropylene.

The main catalyst may include 0.00001 to 0.1 parts by weight, preferably 0.00005 to 0.05 parts by weight, more preferably 0.0001 to 0.01 parts by weight, and most preferably 0.0005 to 0.005 parts by weight, based on 100 parts by weight of the propylene monomer. . At this time, if the content of the main catalyst is less than 0.00001 parts by weight, heat energy may not be sufficiently supplied during polymerization, so the polymerization reaction may not be performed smoothly. This can make it difficult to control the production rate.

The cocatalyst may be at least one selected from the group consisting of triethylaluminum, trimethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, and isoprenylaluminum. Preferably, the cocatalyst may be triethylaluminum, trimethylaluminum or a mixture thereof, and most preferably triethylaluminum.

The cocatalyst may include 0.0001 to 1 part by weight, preferably 0.0005 to 0.5 parts by weight, more preferably 0.001 to 0.1 parts by weight, and most preferably 0.005 to 0.05 parts by weight, based on 100 parts by weight of the propylene monomer. . At this time, if the content of the cocatalyst is less than 0.0001 parts by weight, the polymerization reaction may not be properly performed with the main catalyst, and conversely, if it exceeds 1 part by weight, no further improved polymerization reaction can be expected, and manufacturing costs may increase. there is.

Each of the first donor and the second donor is an external donor, and may be an alkoxysilane having a central atom of silicon (Si) and containing oxygen in an alkyl group. In particular, the first donor and the second donor essentially contain these components, but when mixed at a specific concentration and molar ratio during polymerization of homo polypropylene, the reduction in polymerization activity and molecular weight distribution is maintained at least 5% or less, while xylene By increasing the solubility, the production yield and impact resistance can be significantly improved. If only the first donor is used alone, polymerization activity and molecular weight distribution are maintained at a high level. Xylene solubility may indicate very low values. In addition, when only the second donor is used alone, homopolypropylene powder may be agglomerated, and xylene solubility is significantly increased, but polymerization activity and molecular weight distribution may be reduced, which may not be suitable for the required physical property level.

The first donor and the second donor are included in a concentration of 0.1 to 10 mmol, preferably 0.2 to 8 mmol, more preferably 0.3 to 5 mmol, and most preferably 2 to 5 mmol, based on the total amount of the mixture. can do. At this time, if the content of the first donor and the second donor is less than 0.1 mmol, the polymerization activity may decrease rapidly and the productivity of the homo polypropylene resin may decrease. However, xylene solubility may be significantly reduced.

Also, the molar ratio of the first donor and the second donor may be 1:0.5 to 3.5, preferably 1:0.8 to 3, more preferably 1:0.9 to 1.5, and most preferably 1:1. At this time, if the content of the second donor is less than 0.5 molar ratio, polymerization activity and solubility in xylene are simultaneously reduced, and productivity and marketability of the homo-polypropylene resin may be deteriorated. Furthermore, it may be a cause of weakening the price competitiveness of the product. Conversely, if the molar ratio exceeds 3.5, the polymerization activity may be maintained high, but the xylene solubility value may be excessively reduced.

The first donor may be at least one selected from the group consisting of a C-donor (cyclohexylmethyldimethoxysiilane), a D-donor (dicyclopentyldimethoxysilane), and a P-donor (diisopropyldimethoxysilane), and may be preferably a C-donor.

Specific examples of the first donor include cyclohexyldimethoxymethylsilane, dicyclopentyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, and isobutyl. Isobutylisopropyldimethoxysilane, n-Propyltrimethoxysilane, Isobutylmethyldimethoxysilane, Tetraethoxysilane, Tetramethoxysilane, Isobutyl It may be at least one selected from the group consisting of Isobutyltriethoxysilane, Propyltriethoxysilane, Isobutyltrimethoxysilane, and Cyclohexylethyldimethoxysilane. Preferably, the first donor may be at least one selected from the group consisting of cyclohexyldimethoxymethylsilane, dicyclopentyldimethoxysilane, and diisopropyldimethoxysilane, and most preferably cyclohexyldimethoxymethylsilaneyl. can

The second donor may be an alkoxysilane-based silicon (Si) atom having at least one alkyl group, and preferably may be dimethoxydimethylsilane. Dimethoxydimethylsilane, the second donor, contains two oxygen atoms compared to other conventional methoxytrimethylsilane, trimethoxymethylsilane, or tetramethyl orthosilicate, and is a donor (electron donor), and when used in combination with the first donor, the impact resistance and production yield of the homo-polypropylene resin are further improved by increasing the solubility of xylene while having high polymerization activity and molecular weight distribution. can improve

The hydrogen gas may play a role of inducing chain transfer during polymerization of homo polypropylene, and is applied to the reactor at a pressure of 0.01 to 20 bar, preferably 0.05 to 15 bar, and most preferably 0.1 to 10 bar. can be injected.

The step of preparing the homopolypropylene resin composition is 20 to 150 minutes at a temperature of 70 to 95 ° C. and a pressure of 1 to 5 MPa, preferably 20 to 40 minutes at a temperature of 75 to 85 ° C. and a pressure of 2 to 3 MPa. can polymerize. At this time, if the polymerization temperature, pressure, and time conditions do not satisfy all of the above ranges, the polymerization reaction may not be performed properly because the heat energy required for the polymerization reaction is not sufficiently supplied, and lumps are formed due to aggregation of propylene monomers in the reactor can happen

The homopolypropylene resin composition has a melt index (MI) of 0.1 to 200 g/10min (230°C, 2.16 kg load), preferably 0.5 to 150 g/10min, more preferably 1 to 120 g/10min. 10 min, most preferably 3 to 100 g/10 min.

In general, xylene solubility of polypropylene refers to a weight ratio of polypropylene that is soluble in a xylene solution and polypropylene that is insoluble when polypropylene is mixed in a xylene solution. The change in xylene solubility is directly related to the orientation of the minimum repeating unit of the polypropylene chain, and this orientation is called isotacticity.

High isotacticity means that there are many isotactic parts in which the repeating units of the polypropylene chain are oriented in the same direction, and there are few atactic parts having irregular orientation. The isotactic polypropylene chains have a constant orientation so that the chains can be firmly aligned during formation of the polymer. On the other hand, atactic polypropylene chains have irregular orientation, so the chains cannot be firmly aligned. Because of these characteristics, the atactic part of polypropylene is dissolved in the xylene solution and eluted into the solution phase, resulting in an increase in xylene solubility.

In the present invention, the homopolypropylene resin composition may increase xylene solubility by being directly influenced by the mixing ratio and the two donor structures mixed during polymerization. The orientation of the minimum repeating unit of the polypropylene chain can be determined by the structural characteristics of the donor. The two types of donors used in the present invention have a simple structure, so the ratio of the isotactic part is reduced and the atactic part has irregular orientation. An increase in xylene solubility can be increased.

The homopolypropylene resin composition has a xylene solubility (X/S) of 0.7 to 10% by weight, preferably 0.9 to 6.15% by weight, more preferably 0.92 to 3% by weight, and most preferably 0.92 to 3% by weight. 1.3 wt%. When the homopolypropylene resin composition has a xylene solubility value of 0.7% by weight or less, crystallinity is increased due to high isotactic parts and impact resistance is strengthened, so that it can be applied to high rigidity products. In addition, the homopolypropylene resin composition having a xylene solubility value of 10% by weight or more has an advantage of being applicable to products such as films requiring stretching due to the influence of a high atactic part. As described above, the homopolypropylene resin composition of the present invention is adjusted to have a xylene solubility of 0.7 to 10% by weight to improve the impact resistance and production yield of the product, and at the same time, it can be variously applied to not only high-stiffness products but also film products requiring stretching. can be provided for application.

The homopolypropylene resin composition has a polymerization activity of 39,000 to 47,000 g/g catalyst/hour, preferably 39,600 to 46,500 g/g catalyst/hour, more preferably 42,000 to 45,800 g/g catalyst/hour, most preferably may be 44,500 to 45,400 g/g catalyst/hour. In addition, the homopolypropylene resin composition may have a molecular weight distribution of 4.0 to 4.9, preferably 4.11 to 4.7, and most preferably 4.2 to 4.4. That is, the homo polypropylene resin composition essentially includes two donors, but by mixing these components in a specific content and molar ratio, the polymerization activity and molecular weight distribution are reduced by 5% or less compared to the existing physical properties while maintaining a high level. xylene solubility can be selectively increased.

In particular, although not explicitly described in Examples or Comparative Examples, the homopolypropylene resin composition according to the present invention has impact resistance, impact resistance, and The mechanical properties of dimensional stability, tensile strength, impact strength, elongation and flexibility were evaluated.

As a result, unlike in other conditions and other numerical ranges, it was confirmed that the mechanical properties of excellent impact resistance, dimensional stability, tensile strength, impact strength, elongation and flexibility all showed uniformly excellent values when all of the following conditions were satisfied.

① the main catalyst is a 4th generation Ziegler-Natta containing 1.5 to 2% by weight of titanium, ② the main catalyst contains 0.0005 to 0.005 parts by weight based on 100 parts by weight of the propylene monomer, ③ The cocatalyst is triethylaluminum, ④ the cocatalyst contains 0.005 to 0.05 parts by weight based on 100 parts by weight of the propylene monomer, ⑤ the first donor is cyclohexyldimethoxymethylsilane, and ⑥ the second donor is Dimethoxydimethylsilane; , ⑨ the hydrogen gas is injected at a pressure of 0.1 to 10 bar, and ⑩ preparing the homo-polypropylene resin composition is polymerized at a temperature of 75 to 85 ° C. and a pressure of 2 to 3 MPa for 20 to 40 minutes, ⑪ The homopolypropylene resin composition has a melt index (MI) of 3 to 100 g/10min (230 °C, 2.16 kg load), and ⑫ the homopolypropylene resin composition has xylene solubility (Xylene Solubility, X/ S) is 0.92 to 1.3% by weight, ⑬ the homopolypropylene resin composition may have a polymerization activity of 44,500 to 45,400 g/g catalyst/hour, and a molecular weight distribution of 4.2 to 4.4.

However, when any one of the 13 conditions is not satisfied, the impact resistance and flexibility are significantly lowered, or the physical properties of tensile strength, impact strength and elongation are not uniformly excellent.

On the other hand, the present invention relates to a homopolypropylene resin composition having a melt index (MI) of 0.1 to 200 g/10min (230 °C, 2.16 kg load), the homopolypropylene resin composition has xylene solubility (Xylene Solubility) , X/S) is 0.7 to 10% by weight.

The homopolypropylene resin composition may have a polymerization activity of 39,000 to 47,000 g/g catalyst/hour and a molecular weight distribution of 4.0 to 4.9.

In addition, the present invention provides a molded article manufactured using the homopolypropylene resin composition.

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

Comparative Examples 1 to 10

In the reactor, a propylene monomer with a purity of 99.6%, a 4th generation Ziegler-Natta catalyst (titanium content = 1.5 to 2% by weight) as a main catalyst, triethylaluminium as a cocatalyst and a C-donor (Cyclohexyldimethoxy methylsilane as a first donor) ) was added, and hydrogen was injected at a pressure of 2 bar to prepare a mixture. Then, homopolypropylene was prepared by slurry polymerization of the mixture at a temperature of 80° C. and a pressure of 3.5 MPa for 30 minutes. At this time, in order to increase xylene solubility, homopolypropylene was polymerized by gradually decreasing the mixing amount of the first donor as shown in Table 2 below. In addition, homopolypropylene was polymerized using only the second donor instead of the first donor. At this time, each homopolypropylene resin prepared had a melt index (MI) of 10 to 50 g/10min (230 °C, 2.16 kg load).

Experimental Example 1

For each homopolypropylene resin composition prepared in Comparative Examples 1 to 6, polymerization activity, xylene solubility, and molecular weight distribution were measured by conventional methods, and the results are shown in Table 3.

According to the results of Table 3, in the case of Comparative Example 3, when the injection amount of the first donor decreased by 1/5 or more, it was confirmed that xylene solubility started to increase and polymerization activity also started to decrease rapidly. In particular, in Comparative Examples 4 to 6, the xylene solubility began to increase rapidly compared to the rate of decrease in the donor injection amount. This means that when the injection amount of the donor is reduced below a certain level, an error rate may increase due to a rapid change in xylene solubility.

Experimental Example 2

For each homopolypropylene resin composition prepared in Comparative Examples 1 and 7 to 10, polymerization activity, xylene solubility, and molecular weight distribution were measured in the same manner as in Experimental Example 2, and the results are shown in Table 4.

According to the results of Table 4, compared to the polymerization activity of Comparative Example 1 in which the first donor was mixed, in the case of Comparative Examples 7 to 10, as the number of oxygen atoms in the second donor increased, the polymerization activity rapidly decreased. However, xylene solubility also tended to decrease. In addition, in Comparative Examples 7 and 8, when the second donors A and B were individually mixed, the aggregation of the homo-polypropylene powder was severe, and it was found that this phenomenon was caused by high xylene solubility. Through this, it was confirmed that it is very difficult to simultaneously improve polymerization activity, molecular weight distribution, and xylene solubility within an appropriate range by mixing the first donor and the second donor alone. On the other hand, in Comparative Examples 9 and 10, when the second donors C and D were mixed, respectively, there was no agglomeration, but the polymerization activity was remarkably low, so no further experiments were conducted in the present invention.

Examples 1 and 2 and Comparative Examples 1 and 11 to 16

In the same manner as in Comparative Example 1, homopolypropylene was polymerized by mixing the second donors (A and B) with the first donor as shown in Table 5 below. At this time, as the second donor, methoxytrimethylsilane (A) and dimethoxydimethylsilane (B) were respectively used. In addition, homopolypropylene was polymerized by additionally using a fourth-generation Ziegler-Natta catalyst having a titanium content of 1 to 1.4% by weight as a main catalyst.

Experimental Example 3

For each homopolypropylene resin composition prepared in Examples 1 and 2 and Comparative Examples 1 and 11 to 14, polymerization activity, xylene solubility, and molecular weight distribution were measured in the same manner as in Experimental Example 2, and the results are shown in Table 6. shown in

According to the results of Table 6, compared to Comparative Example 1 using only the first donor, in Comparative Examples 11 and 12 in which the second donor A was mixed, the polymerization activity increased, and the xylene solubility increased by 1.16 times, respectively. , it was confirmed that it increased by 1.41 times. However, this increase alone could not be seen as a large increase enough to change the use of homopolypropylene.

On the other hand, in the case of Example 1 in which the first donor and the second donor B were mixed in the same ratio, the polymerization activity was 0.97 times lower and the molecular weight distribution was 0.99 times lower than that of Comparative Example 1, but the xylene solubility was 2.49 times lower. increased about twice as much. These results show that xylene solubility can be greatly increased without significantly affecting polymerization activity and molecular weight distribution. In addition, when compared to Comparative Example 4 having similar xylene solubility values, it was found that the polymerization activity of Example 1 was about 12% higher.

Through this, the polymerization activity and xylene solubility values as in Example 1 were applicable to the actual process, and even by adjusting only the specific component and mixing amount of the second donor, the xylene solubility could be significantly increased without a significant decrease in activity. confirmed that there is However, in the case of Comparative Example 13 in which the injected amount of component B, which is the second donor, was further increased, the solubility of xylene was increased, but the polymerization activity was reduced by 0.44 times, and it was found that the level could not be used in the actual process.

In addition, in the case of Example 2, in which the total number of moles of the first donor and the second donor (B) was low, the polymerization activity was increased by 1.02 times, the solubility of xylene was increased by 2.55 times, and the molecular weight was increased by 2.55 times compared to Comparative Example 14 using the first donor alone. It was confirmed that the distribution was increased to a level of 0.98 times. This confirms that the method of mixing the second donor (A) with the first donor of the present invention can be applied in a range of donor concentrations.

Experimental Example 4

For each homopolypropylene resin composition prepared in Example 1 and Comparative Examples 1, 15, and 16, polymerization activity, xylene solubility, and molecular weight distribution were measured in the same manner as in Experimental Example 2, and the results are shown in Table 7. was

According to the results of Table 7, in the case of Example 1 using the main catalyst having a titanium content of 1.5 to 2%, compared to Comparative Example 1, the polymerization activity was reduced to 0.97 times and the molecular weight distribution was reduced to 0.99 times, but xylene. Solubility increased significantly by 2.49 times.

In addition, in the case of Example 3 using the main catalyst having a titanium content of 1 to 1.4%, the polymerization activity was increased by 1.02 times and the solubility in xylene by about 2.46 times compared to Comparative Example 15, and the molecular weight distribution was reduced by 0.95 times. appear. These results confirm that the method of mixing the second donor (A) with the first donor of the present invention can be universally applied to 4th generation Ziegler-Natta catalysts having various concentrations of titanium. In addition, in the case of Comparative Example 15 and Example 3, it was found that the polymerization activity was low because the titanium content of the main catalyst was smaller than that of Comparative Example 1 and Example 1.

Claims (15)

preparing a mixture by introducing a propylene monomer, a main catalyst, a cocatalyst, a first donor and a second donor into a reactor and then injecting hydrogen gas; and
Polymerizing the mixture to prepare a homopolypropylene resin composition; Including,
The first donor and the second donor are included in a concentration of 2 to 5 mmol based on the total content of the mixture,
The molar ratio of the first donor and the second donor is 1: 0.9 to 1.5,
The homopolypropylene resin composition has a xylene solubility (X/S) of 0.92 to 1.3% by weight,
The main catalyst is a 4th generation Ziegler-Natta containing 1.5 to 2% by weight of titanium,
The main catalyst contains 0.0005 to 0.005 parts by weight based on 100 parts by weight of the propylene monomer,
The cocatalyst is triethylaluminum,
The cocatalyst contains 0.005 to 0.05 parts by weight based on 100 parts by weight of the propylene monomer,
The first donor is cyclohexyldimethoxymethylsilane,
The second donor is dimethoxydimethylsilane,
The hydrogen gas is injected at a pressure of 0.1 to 10 bar,
The step of preparing the homopolypropylene resin composition is polymerization at a temperature of 75 to 85 ° C. and a pressure of 2 to 3 MPa for 20 to 40 minutes,
The homo polypropylene resin composition has a melt index (MI) of 3 to 100 g/10 min (230 ° C, 2.16 kg load),
The homopolypropylene resin composition has a polymerization activity of 44,500 to 45,400 g/g catalyst/hour and a molecular weight distribution of 4.2 to 4.4. delete delete delete delete delete delete delete delete delete delete delete delete delete delete