KR101831528B1 - High melt flow polypropylene resin composition having improved stiffness and impact strength and preparing method same - Google Patents

Abstract

Disclosed are a polypropylene resin composition with improved rigidity and impact strength and rigidity as well as flow mark characteristics of an impact block copolymer, which can be produced using a Spherizone process, and a manufacturing method thereof. The present invention provides the polypropylene resin composition, which comprises 0.01 to 0.5 wt% of a phosphorus antioxidant, 0.01 to 0.5 wt% of a phenolic antioxidant, and 0.01 to 0.5 wt% of a neutralizing agent, based on 100 wt% of the impact block copolymer, which has a melt index of 50 to 120 g/10 min at the temperature of 230°C and the load of 2.16kg, and also provides the manufacturing method thereof.

Description

TECHNICAL FIELD [0001] The present invention relates to a high-strength polypropylene resin composition having improved rigidity and impact strength, and a method of manufacturing the same. BACKGROUND ART < RTI ID = 0.0 >

The present invention relates to a polypropylene resin composition, and more particularly, to a high-flow polypropylene resin composition improved in rigidity and impact strength using a high-dynamic impact block copolymer.

Impact block copolymers are general-purpose olefin resins used in special situations requiring high impact resistance. They are used in a wide variety of applications, including food containers, automotive supplies, household goods, and industrial materials. Impact block copolymers are used in a variety of ways because they are less toxic than other plastics and have better physical properties such as low temperature impact strength than homo-polypropylene and good processability. Particularly, impact block copolymer having high flow rate is widely used for thin-walled containers and large injection molding because of good flowability.

A general impact block copolymer polymerization method is a method in which a catalyst and a propylene monomer are charged in a loop reactor to prepare a homo-polypropylene, and then an ethylene monomer is added in a gas phase reactor to form an amorphous ethylene-propylene copolymer, And an ethylene-propylene copolymer. The ethylene-propylene copolymer is in the form of an amorphous rubber and islands in the homo-polypropylene matrix. The absolute content, size and degree of dispersion of the ethylene-propylene copolymer affect the impact strength and flow mark characteristics of the block copolymer.

Recently, impact block copolymers having a melt index of 50 to 120 g / 10 min are mainly used as automobile parts are enlarged and high-speed injection molding technology is developed. However, due to the high melt index, the impact strength of the compound product does not meet the standards set by the automobile company. Therefore, when making compound products, rubber such as ethylene propylene rubber (EPR) or ethylene butene rubber (EBR) is added to increase the impact strength. However, due to the high viscosity of the added rubber and propylene-ethylene copolymer, a flow mark is generated in the molded article of the compound.

On the other hand, in order to produce a high-impact block copolymer product having a melt index (MI) of 35 g / 10 min (230 ° C, 2.16 kg load) or more, a method of adding a peroxide (see Prior Art 1) (See the prior art documents 2 and 3). The Spherizone process (Basell), as is known in the art, differs from the spheripol and Hypol II polymerization processes known in the art in that there is one reactor that produces homopropylene and the propylene monomer It is difficult to produce high-quality homo-homopropylene and it is impossible to produce a high-dynamic impact block copolymer having a melt index of 35 g / 10 min or more. Addition of peroxide to produce such a high-impact block copolymer can produce products with a melt index of 35 g / 10 min or more. However, the use of peroxide causes the yellowing phenomenon and odor in which the color turns yellow during injection molding.

[Prior Art]

- Prior Art 1: Korean Published Patent No. 10-2012-0051687 (2012.05.22)

- Prior Art 2: Korean Patent Publication No. 10-2014-0033225 (Apr. 17, 2014)

- Prior Art 3: Korean Patent Laid-Open No. 10-2009-0007044 (Jan. 16, 2009)

- Prior Art 4: Korean Patent No. 10-1081713 (2011.11.22.)

The present invention provides a polypropylene resin composition having improved impact strength and rigidity as well as flow mark characteristics of an impact block copolymer which can be produced using a Spherizone process, and a process for producing the same.

In order to solve the above-described problems, the present invention provides a process for producing an impact block copolymer comprising 0.01 to 0.5 parts by weight of a phosphorus-based antioxidant, 0.01 to 0.5 parts by weight of a phenol-based antioxidant 0.01 to 100 parts by weight of an impact block copolymer having a melt index To 0.5 parts by weight of a polypropylene resin and 0.01 to 0.5 parts by weight of a neutralizing agent.

Also, the impact block copolymer has an ethylene content of 4 to 6% by weight.

The present invention also provides a polypropylene resin composition characterized in that the phosphorus antioxidant is tris (2,4-di-t-butylphenyl) phosphite.

And the phenolic antioxidant is tetrakis [ethylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methadecene.

Also, the polypropylene resin composition is characterized in that the neutralizing agent is calcium stearate.

The polypropylene resin composition further comprises a nucleating agent.

(Ethylene / propylene) molar ratio of 0.30 to 0.35 and (hydrogen / ethylene) molar ratio of 20 to 25 in a gas phase reactor, in which the propylene monomer and the catalyst are fed into a sperior zone polymerization reactor, (230 ° C, 2.16 kg load) of 50 to 120 g / 10 min, and an ethylene content of 4 to 6% by weight based on the weight of the impact block copolymer; And 0.01 to 0.5 parts by weight of a phenolic antioxidant and 0.01 to 0.5 parts by weight of a neutralizing agent per 100 parts by weight of the impact block copolymer. ≪ / RTI >

The present invention relates to a process for producing high impact polypropylene resin composition using a Spherizone process, in which an impregnation block copolymer is produced by optimizing a raw material injection condition of a gas phase reactor to produce polypropylene having improved impact strength and rigidity, A resin composition can be provided.

In addition, when the high impact block copolymer is produced in the Spherizone process, it is impossible to produce an impact block copolymer having a melt index of 35 g / 10 min or more without addition of peroxide. However, Is a high-dynamic impact block copolymer which is controlled by the pressure of the reactor and the amount of addition of hydrogen, and can realize a high melt viscosity of 35 g / 10 min or more without addition of peroxide.

In addition, the impact block copolymer used in the present invention can control the mechanical properties by adjusting the impact strength and viscosity of the high impact block copolymer by increasing the absolute content of the ethylene-propylene copolymer by controlling the amount of hydrogen and ethylene added in the gas phase reactor And has the effect of reducing color and odor.

In addition, when injection molding an automobile bumper or the like using a high-dynamic copper product containing peroxide, gas generation and flow mark are generated. However, since the product polymerized through the present invention has improved flowability, There is an effect that the flow mark generation and the flow mark problem are improved.

In addition, it can reduce the ethylene content compared to general impact block copolymers, and it can fully meet the stiffness standards required especially by automobile companies.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a photograph showing the appearance of a combustible specimen ejected using a compound product of an impact block copolymer according to Examples and Comparative Examples. Fig.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. It is to be understood that various equivalents and modifications may be substituted for those at the time of the present application.

In one embodiment, 0.01 to 0.5 parts by weight of a phosphorus-based antioxidant, 0.01 to 0.5 parts by weight of a phenolic antioxidant is added to 100 parts by weight of an impact block copolymer having a melt index (230 DEG C, 2.16 kg load) of 50 to 120 g / And 0.01 to 0.5 parts by weight of a neutralizing agent.

In the present invention, the impact block copolymer was produced through a Spherizone process. Unlike the conventional reactor, it was impossible to produce a high-impact block copolymer having a melt index of 35 g / 10 min or more without adding peroxide. However, By controlling the amount of pressure and hydrogen added, it is possible to produce a high dynamic impact block copolymer.

The impact block copolymer preparation through the Spherizone process is carried out in a gas phase polymerization process to polymerize homopolypropylene in an MZCR (Muti Zone Circulating Reaction) polymerization process and to produce an ethylene-propylene copolymer. The MZCR polymerization process consists of a single loop reactor, which limits the production of inherent homopropylene. Therefore, there is a drawback that an impact block copolymer having a melt index of 35 g / 10 min or more can not be produced. In the present invention, it is possible to produce an intrinsic impact block copolymer by increasing the pressure in order to improve it.

That is, in order to achieve high fluidity in the manufacture of an impact block copolymer using a Spherizone process, there is no known solution for controlling the pressure of the reactor and controlling the amount of hydrogen. However, in the present invention, It is possible to easily produce a high-dynamic impact block copolymer having a melt index of 35 g / 10 min or more by controlling the amount of hydrogen to be added to a specific range.

At this time, the loop reactor pressure can be adjusted to 28 to 40 atm to produce a high-dynamic impact block copolymer having a melt index of 35 g / 10 min or more. In particular, in order to realize a melt index of 50 to 120 g / 10 min, the loop reactor pressure is preferably adjusted to 30 to 35 atm, more preferably 30 to 33 atm.

Thus, by controlling the reactor pressure in the Spherizone process, it is possible to easily produce the high-impact block copolymer by controlling the amount of hydrogenation in the polymerization reactor without adding peroxide.

Here, in order to prevent the impact strength from being lowered due to the implementation of the high flowability, the present invention controls the ethylene, propylene, and hydrogen contents injected into the gas phase reactor.

Accordingly, the present invention provides, as another embodiment, a propylene polymerization reactor in which a propylene monomer and a catalyst are fed and a molar ratio of [ethylene / (ethylene + propylene)] of 0.30 to 0.35 and a hydrogen / ethylene To produce an impact block copolymer having a melt index (230 DEG C, 2.16 kg load) of 50 to 120 g / 10 min and an ethylene content of 4 to 6 wt%; And 0.01 to 0.5 parts by weight of a phenolic antioxidant and 0.01 to 0.5 parts by weight of a neutralizing agent per 100 parts by weight of the impact block copolymer. / RTI >

According to the present invention, a large amount of an ethylene-propylene copolymer is produced by maintaining the molar ratio of [ethylene / (ethylene + propylene)] and the (hydrogen / ethylene) molar ratio in the gas phase reactor at the time of producing impact block copolymer. The impact strength can be improved at the same time, and the flow mark can be remarkably improved.

That is, when the molecular weight of the ethylene-propylene copolymer is high, a flow mark is generated in injection molding of an automobile part due to a high viscosity, and a gas mark appears on the surface. However, the polymerized product according to the present invention can control the molecular weight of the ethylene-propylene copolymer, thereby improving gas generation and flow mark problems. In addition, yellowing phenomenon and odor problem in which the color of the injection molded article is changed to yellow by using no organic peroxide is improved.

Hereinafter, each constitution of the polypropylene resin composition according to the present invention will be described in more detail.

(1) Impact block copolymer

In the present invention, the impact block copolymer is prepared through a Spherizone reactor. For example, a propylene monomer is placed in a speriorion polymerization reactor, triethylaluminum, a phthalate catalyst, and a silane-based electron donor are introduced, vapor phase polymerization is carried out at a reaction temperature of 68 to 75 ° C and a predetermined atmospheric pressure to obtain an impact blocker Polymers can be produced, which can produce high-flow products by hydrogen.

The ethylene content of the impact block copolymer for high throughput implementation may be 4-6 wt%. When the ethylene content is less than 4% by weight, the impact strength is low, which may be unsuitable for injection purposes. If the ethylene content is more than 6% by weight, the impact strength is excellent but the rigidity is low.

The impact block copolymer resin may have a melt index of 50 to 120 g / 10 min (230 ° C, 2.16 kg load), preferably 60 to 100 g / 10 min. If the melt index is less than 50 g / 10 min, it can not be used as a thin film or a high-flow product. If the melt index exceeds 120 g / 10 min, the flow of the product is increased but the polypropylene extrusion process condition must be changed. There is a disadvantage that it is fragile.

(2) Antioxidants

The polypropylene resin composition according to the present invention is required to simultaneously contain a phosphorus-based antioxidant and a phenol-based antioxidant as additives, wherein 0.01 to 0.5 parts by weight of the phosphorus-based antioxidant is added to 100 parts by weight of the impact block copolymer, Based antioxidant is 0.01 to 0.5 parts by weight. Preferably, 0.05 to 0.15 parts by weight of the phosphorus antioxidant and 0.05 to 0.2 parts by weight of the phenolic antioxidant may be included.

If the content of the phosphorus antioxidant is less than 0.01 part by weight, pyrolysis of the polypropylene resin itself may occur during processing, adversely affecting the physical properties. If the content is more than 0.5 parts by weight, the color change after molding may be affected.

When the content of the phenolic antioxidant is less than 0.01 part by weight, the physical properties such as the yield stress may be affected. When the amount of the phenolic antioxidant is more than 0.5 parts by weight, Can affect the color change.

The phosphorus-based antioxidant and the phenol-based antioxidant are not particularly limited, and they may be used alone or in combination of two or more thereof. However, in view of maintaining an optimum level of low-temperature impact strength and flexural modulus, the phosphorus antioxidant is tris (2,4-di-t-butylphenyl) phosphite, the phenolic antioxidant is tetrakis [ Di-t-butyl-4-hydroxyphenyl) propionate] methane.

(3) Neutralizer

In order to neutralize the residual catalyst in the polypropylene resin, the polypropylene resin composition according to the present invention may contain 0.01 to 0.5 parts by weight, preferably 0.05 to 0.2 parts by weight, of a neutralizing agent based on 100 parts by weight of the impact block copolymer.

Examples of the neutralizing agent include fatty acid metal salts such as lithium stearate, calcium stearate and sodium stearate, and fatty acid amides such as ethylenebisstearoamide and stearic acid amide. However, It is preferable to use calcium stearate in view of the above.

In addition, the present invention may further include a nucleating agent to prevent a decrease in rigidity and a decrease in heat resistance due to a decrease in a heat distortion temperature due to a decrease in flexural modulus. The nucleating agent may be added in an amount of 0.05 to 1 part by weight, preferably 0.1 to 0.3 part by weight based on 100 parts by weight of the impact block copolymer. When the content of the nucleating agent is less than 0.05 part by weight, it is difficult to obtain a sufficient flexural modulus and the crystallization rate effect may be deteriorated. When the amount of the nucleating agent is more than 1 part by weight, low temperature impact strength is lowered and further property improvement in terms of flexural modulus and crystallization speed is expected It can be difficult.

As such a nucleus agent, organic nucleating agents such as zinc and calcium salt compounds, sorbitol compounds, phosphoric acid ester compounds and the like and inorganic nucleating agents such as talc can be used, but the remarkable improvement in rigidity and the rate of crystallization are further shortened, It is most preferable to use zinc and calcium salt compounds in order to maintain an optimum level of zinc and calcium salts.

In addition, the low-temperature impact strength and flexural modulus of the polypropylene resin composition to which the antistatic agent, the anti-blocking agent, the slip agent, the weathering / light stabilizer, the pigment, It can be added within a range that does not deteriorate.

The molded article produced by using the high-dynamic impact block copolymer according to the present invention has excellent stiffness and IZOD impact strength properties and can be effectively used as a component material for automobiles, particularly, since the problem of flow marks is improved.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. However, the following examples are illustrative of the present invention, and the present invention is not limited to the examples described below.

Example

Ethylene / ethylene / propylene copolymer was injected into a speriorion polymerization reactor at a reaction temperature of 68 to 75 ° C and a pressure of 30 to 33 atm. (Ethylene / propylene) gas molar ratio of 0.30 to 0.35 and a (hydrogen / ethylene) gas molar ratio of 20 to 25 to obtain an impact block having an ethylene content of 4.5 to 5.0 wt% and a melt index of 100 to 110 g / Copolymer. Thereafter, 0.15 part by weight of a phosphorus antioxidant (tris (2,4-di-t-butylphenyl) phosphite, Songwon Industry), 0.15 part by weight of a phenolic antioxidant (tetrakis 0.1 part by weight of a neutralizing agent (calcium stearate, Songwon Industry) and 0.1 part by weight of a nucleating agent (NA-902 (trade name) , Adeka) were mixed and mixed in a Henschel mixer for 5 minutes, followed by extrusion with a twin-screw extruder at 180 to 220 ° C to obtain a pellet-shaped polypropylene resin composition.

Comparative Example  One

Ethylene / ethylene / propylene copolymer was injected into a speriorion polymerization reactor at a reaction temperature of 68 to 75 ° C and a pressure of 30 to 33 atm. (Ethylene / propylene) gas molar ratio of 0.30 to 0.35 and a (hydrogen / ethylene) gas molar ratio of 10 to 15 to obtain an impact block having an ethylene content of 4.5 to 5.0% by weight and a melt index of 100 to 110 g / Copolymer. Thereafter, 0.15 part by weight of a phosphorus antioxidant (tris (2,4-di-t-butylphenyl) phosphite, Songwon Industry), 0.15 part by weight of a phenolic antioxidant (tetrakis 0.1 part by weight of a neutralizing agent (calcium stearate, Songwon Industry) and 0.1 part by weight of a nucleating agent (NA-902 (trade name) , Adeka) were mixed and mixed in a Henschel mixer for 5 minutes, followed by extrusion with a twin-screw extruder at 180 to 220 ° C to obtain a pellet-shaped polypropylene resin composition.

Comparative Example  2

Ethylene / ethylene / propylene copolymer was injected into a speriorion polymerization reactor at a reaction temperature of 68 to 75 ° C and a pressure of 30 to 33 atm. (Ethylene / propylene) gas molar ratio of 0.40 to 0.45 and a (hydrogen / ethylene) gas molar ratio of 20 to 25 to obtain an impact block having an ethylene content of 4.5 to 5.0 wt% and a melt index of 100 to 110 g / Copolymer. Thereafter, 0.15 part by weight of a phosphorus antioxidant (tris (2,4-di-t-butylphenyl) phosphite, Songwon Industry), 0.15 part by weight of a phenolic antioxidant (tetrakis 0.1 part by weight of a neutralizing agent (calcium stearate, Songwon Industry) and 0.1 part by weight of a nucleating agent (NA-902 (trade name) , Adeka) were mixed and mixed in a Henschel mixer for 5 minutes, followed by extrusion with a twin-screw extruder at 180 to 220 ° C to obtain a pellet-shaped polypropylene resin composition.

Comparative Example  3

Ethylene / ethylene / propylene copolymer was injected into a speriorion polymerization reactor at a reaction temperature of 68 to 75 ° C and a pressure of 30 to 33 atm. (Ethylene / propylene) gas molar ratio of 0.50 to 0.55 and a (hydrogen / ethylene) gas molar ratio of 20 to 25 to obtain an impact block having an ethylene content of 4.5 to 5.0% by weight and a melt index of 100 to 110 g / Copolymer. Thereafter, 0.15 part by weight of a phosphorus antioxidant (tris (2,4-di-t-butylphenyl) phosphite, Songwon Industry), 0.15 part by weight of a phenolic antioxidant (tetrakis 0.1 part by weight of a neutralizing agent (calcium stearate, Songwon Industry) and 0.1 part by weight of a nucleating agent (NA-902 (trade name) , Adeka) were mixed and mixed in a Henschel mixer for 5 minutes, followed by extrusion with a twin-screw extruder at 180 to 220 ° C to obtain a pellet-shaped polypropylene resin composition.

Experimental Example  One

The pellet-shaped polypropylene resin compositions prepared according to the above Examples and Comparative Examples were extruded using a molding extruder (Lotte Chemical) to form ASTM physical property measuring specimens. Molding was performed using an FMVSS combustible mold (Lotte Chemical) Respectively. The physical properties of each molded specimen were measured in the following manner, and the results of the measurement are shown in Table 1 below.

[Measurement of physical properties]

1) Melt index: measured according to ASTM evaluation method D1238 at 230 占 폚 under a load of 2.16 kg.

2) Ethylene-Propylene Copolymer Content: The sample was extracted with xylene.

3) Ethylene-propylene copolymer viscosity: The ethylene-propylene copolymer obtained using the xylene was analyzed by GPC.

4) Flexural modulus: According to ASTM evaluation method D790, ASTM injection specimens were measured at 23 ° C and 50% relative humidity.

5) IZOD Impact Strength: A 3 mm thick, notched injection specimen was measured at 23 ° C and 50% relative humidity according to ASTM Rating Method D256.

The results of the absolute content of the ethylene-propylene copolymer and the IZOD impact strength (23 ° C) were as follows. Ethylene-propylene copolymer (ethylene / propylene) (Ethylene / (ethylene + propylene)] gas molar ratio was 0.40 to 0.55 (Comparative Examples 2 and 3), which was 7.6 to 9.4 wt% The results of the IZOD impact strength (23 ° C) showed that the Examples and Comparative Examples 1 were 4.8 to 4.9 kg · cm / cm, which were somewhat higher than the 2.9 to 3.0 kg · cm / cm levels of Comparative Examples 2 and 3. This is because the molar ratio of [ethylene / (ethylene + propylene)] From 0.30 to 0.35, the most ethylene-propylene copolymer is produced, and the impact strength is proportional to the content of the ethylene-propylene copolymer.

On the other hand, to check the rigidity of the impact block copolymer, the flexural modulus was tested and when the flexural modulus was high, the stiffness was high. In general, the stiffness and impact strength of impact block copolymers are inversely proportional. The flexural modulus was 18,200 to 18,500 kgf / cm 2 at the IZOD impact strength and the flexural modulus at 18,900 to 19,400 kgf / cm 2 at the comparative examples 2 and 3 where the IZOD impact strength was low Respectively. The flexural modulus of a typical impact block copolymer is known to be in the range of 12,000 to 13,000 kgf / cm 2.

Experimental Example  2

As another experiment for confirming whether or not a flow mark was generated, a pellet image was prepared by using the manufacturing method used for automobile bumper injection molding with respect to the impact block copolymer produced according to Examples and Comparative Examples. The compound was prepared by mixing 60 to 70 parts by weight of an impact block copolymer, 10 to 20 parts by weight of rubber, and 10 to 20 parts by weight of talc in a Henschel mixer for 5 minutes and then extruded by a twin screw extruder at 180 to 220 DEG C . Thereafter, an injection molded article was molded using an FMVSS combustible mold (length × length, 35 cm × 10 cm, Lotte Chemical).

Fig. 1 is a photograph showing the appearance of a combustible specimen ejected using a compound product of an impact block copolymer according to Examples and Comparative Examples. Fig.

Referring to FIG. 1 and Table 1, when the molar ratio of (hydrogen / ethylene) gas was in the range of 20 to 25 (Examples, Comparative Examples 2 and 3) The hydrogen / ethylene gas molar ratio of the gas phase polymerizer is 20 to 25, the viscosity of the ethylene-propylene copolymer is lowered and the flow rate of the ethylene / propylene copolymer is lowered. It also shows improvement of national problems.

While the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, Such modifications and changes are to be considered as falling within the scope of the following claims.

Claims (7)

Propylene monomer and a catalyst were fed into a Spherrizon polymerization reactor and vapor-phase polymerized into a gas phase reactor at a molar ratio of [ethylene / (ethylene / propylene)] of 0.30 to 0.35 and a hydrogen / ethylene mole ratio of 20 to 25 to obtain a melt index占 폚, 2.16 kg load) of 50 to 120 g / 10 min and an ethylene content of 4 to 6% by weight; And
Mixing and extruding 0.01 to 0.5 parts by weight of a phosphorus antioxidant, 0.01 to 0.5 parts by weight of a phenol antioxidant and 0.01 to 0.5 parts by weight of a neutralizer, based on 100 parts by weight of the impact block copolymer;
By weight based on the total weight of the polypropylene resin composition. delete The method according to claim 1,
Wherein the phosphorus antioxidant is tris (2,4-di-t-butylphenyl) phosphite. The method according to claim 1,
Wherein the phenolic antioxidant is tetrakis [ethylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methadecane. The method according to claim 1,
Wherein the neutralizing agent is calcium stearate. The method according to claim 1,
Wherein the mixing and extruding is performed by further mixing a nucleating agent. delete

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