KR101846716B1 - Ethylene propylene impact copolymers - Google Patents

Abstract

Disclosed are an ethylene propylene block copolymer resin composition capable of satisfying both impact strength and transparency and a molded article manufactured therefrom. The present invention provides an ethylene propylene block copolymer resin composition which step-polymerizes ethylene propylene rubber (EPR) comprising (a) 85-95 wt% of a crystalline propylene homopolymer and (b) 40-70 wt% of ethylene in a reactor, and a molded article manufactured therefrom.

Description

ETHYLENE PROPYLENE IMPACT COPOLYMERS < RTI ID = 0.0 >

The present invention relates to a polypropylene resin composition, and more particularly, to a polypropylene resin composition excellent in impact resistance, rigidity and transparency.

In general, the polypropylene resin composition is lightweight and has excellent mechanical and mechanical properties at a price, and is widely used as an injection molded article or a film material. In recent years, the use of polypropylene products has been expanding to various fields where durability is required depending on the user's environment in a simple external finish material or a packaging material. Particularly, as products using polypropylene are becoming larger, products are becoming thinner in order to reduce weight of products. However, such a thin film has a problem that it is easily broken by an external impact, and in order to improve it, there is a demand for a polypropylene product having a high stiffness and a higher level of impact resistance. However, in the development of materials using polypropylene, the impact resistance and stiffness tend to be inversely proportional, and a composition having high impact resistance is inadequate as a transparent container material that is invisible in inverse proportion to transparency.

Thus, it is required to develop a material that can satisfy both the impact strength and transparency required when used as a film packaging material, a food storage container, or a small injection container.

Korean Patent No. 1598715 discloses an ethylene propylene block copolymer prepared by using 65 to 82% by weight of a propylene homopolymer and 18 to 35% by weight of an ethylene propylene rubber having an ethylene content of 25 to 50% by weight, (Blur, impact strength, heat bonding strength, appearance characteristics) of the amorphous ethylene propylene rubber phase composition and domain size control are not fully explained.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide an ethylene propylene block copolymer resin composition which can satisfy both impact strength and transparency and a molded article produced therefrom.

SUMMARY OF THE INVENTION The present invention relates to an ethylene propylene rubber (EPR) composition comprising (a) 85 to 95% by weight of a crystalline propylene homopolymer and (b) 40 to 70% by weight of ethylene, And 5 to 15% by weight of the propylene block copolymer is polymerized stepwise in the reactor.

And the intrinsic viscosity ratio of the amorphous ethylene propylene rubber (b) to the crystalline propylene homopolymer (a) is 0.5 to 1. The present invention also provides an ethylene propylene block copolymer resin composition.

Also, the amorphous ethylene propylene rubber (b) has an average diameter of 100 to 500 nm.

The resin composition may further comprise at least one additive selected from the group consisting of an antioxidant, a catalyst neutralizing agent, a pigment, a dispersant, a lubricant, an antistatic agent, a UV stabilizer, a slip agent, an antiblocking agent and talc Ethylene propylene block copolymer resin composition.

In order to solve the above-mentioned problems, the present invention provides a molded article produced from the resin composition.

The molded article may be any one of a refrigerated container, a freezing container, a multipurpose container, an automobile interior / exterior material, a food packaging container, a bottle cap, a packaging film, a protective film, a decor sheet, a retort pouch, Thereby providing a molded article.

According to the present invention, an amorphous ethylene propylene rubber (EPR) in an optimal amount is gradually polymerized to a crystalline propylene homopolymer, and Fish-eye is obtained by controlling the optimum intrinsic viscosity ratio and domain size. An ethylene propylene block copolymer resin composition which is excellent in heat resistance and satisfies transparency and impact resistance at the same time, and a molded article produced therefrom can be provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly explain the present invention, parts not related to the description are omitted, and similar parts are denoted by similar reference numerals throughout the specification.

The present invention relates to a process for the preparation of (a) an ethylene-propylene rubber composition comprising 85 to 95% by weight of crystalline propylene homopolymer and 5 to 15% by weight of an amorphous ethylene propylene rubber (EPR) comprising 40 to 70% Discloses a step-polymerized ethylene propylene block copolymer resin composition. Hereinafter, each component constituting the present invention will be described in detail.

(a) a crystalline propylene homopolymer

In the present invention, the crystalline propylene homopolymer is polymerized by injecting propylene alone in the polymerization reactor. The method of polymerizing the polymer is by a conventional method known in the art, and is not particularly limited in the present invention.

The crystalline propylene homopolymer is contained in an amount of 5 to 95% by weight in the total ethylene propylene block copolymer resin composition. When the content of the crystalline propylene homopolymer is less than 85% by weight, the crystallinity is lowered to deteriorate the heat resistance and the heat bonding property, and when it exceeds 95% by weight, the crystallinity increases sharply and the impact resistance is lowered.

(b) Amorphous ethylene propylene rubber

In the present invention, the amorphous ethylene propylene rubber is polymerized simultaneously with ethylene and propylene, and after the crystalline propylene homopolymer is polymerized, it is continuously polymerized in the presence of the crystalline propylene homopolymer in the subsequent polymerization reactor. The polymerization method of the amorphous ethylene propylene rubber is by a conventional method known in the art and is not particularly limited in the present invention.

In the present invention, since the amorphous ethylene propylene rubber is continuously polymerized in the reactor after polymerization of the crystalline propylene homopolymer, and a part of the constituent material of the crystalline propylene homopolymer and the amorphous ethylene propylene rubber is the same as the propylene chain, It is possible to uniformly disperse by the affinity, to have excellent transparency, to minimize the deterioration of the heat bonding property, to improve the impact resistance strength, and to suppress the occurrence of fish eye and orange peel due to the aggregation of the amorphous ethylene propylene rubber.

Accordingly, in the present invention, the amorphous ethylene propylene rubber is contained in an amount of 5 to 15% by weight in the total ethylene propylene block copolymer resin composition in order to balance physical properties such as impact strength, thermal adhesiveness, transparency and appearance. If the content of the amorphous ethylene propylene rubber is less than 5% by weight, the impact strength is lowered, and if it is more than 15% by weight, the thermoadhesiveness, transparency and appearance characteristics are deteriorated.

The amorphous ethylene propylene rubber may have an ethylene content of 40 to 70% by weight, and preferably 50 to 60% by weight based on the total weight of the rubber. When the ethylene content in the copolymer is less than 40% by weight, the amorphous portion improving the impact in the polymer block to be polymerized is reduced and the impact resistance property is decreased. When the ethylene content is more than 70% by weight, And the transparency or anti-whitening characteristics may be reduced due to interfacial peeling at the time of impact resistance.

The intrinsic viscosity (xylene solvent) of the solvent extract in the amorphous ethylene propylene rubber is preferably 0.5 to 2.5 dl / g. When the intrinsic viscosity is less than 0.5 dl / g, the size of the rubber component is small and the molecular weight of the rubber component is small, so that the impact characteristics may be deteriorated. When the intrinsic viscosity exceeds 2.5 dl / g, And transparency is deteriorated due to lowering of dispersibility, and a fish eye may occur. In addition, due to this aggregation phenomenon, the impact resistance at the fish eye part may be deteriorated.

Since the dispersion of the rubber is caused by the difference in viscosity between the crystalline propylene homopolymer and the amorphous ethylene propylene rubber, the ratio of the intrinsic viscosity of the amorphous ethylene propylene rubber to the intrinsic viscosity of the crystalline propylene homopolymer (amorphous ethylene propylene Intrinsic viscosity of the rubber / intrinsic viscosity of the crystalline propylene homopolymer) is preferably 0.5 to 1.

If the intrinsic viscosity ratio is less than 0.5, the polymerized amorphous ethylene propylene rubber may have a lower molecular weight than that of the crystalline propylene homopolymer, which is a continuous phase, so that it may be difficult to absorb shock. If the intrinsic viscosity ratio is more than 1, And the appearance characteristics may be deteriorated.

In the present invention, it is particularly preferable that the amorphous ethylene propylene rubber is finely dispersed in the crystalline propylene homopolymer in an average particle size of 100 to 500 nm. If the particle size of the amorphous ethylene propylene rubber is less than 100 nm, shock absorption and dispersion of the block copolymer may be difficult. If the particle size exceeds 500 nm, the occurrence of diffuse reflection of light may be severe and the transparency may be deteriorated.

The ethylene propylene block copolymer resin composition comprising the crystalline propylene homopolymer (a) and the amorphous ethylene propylene rubber (b) has a melt index (ASTM D1238, 230 ° C / 2.16 kg, Melt Index, MI) of 1 to 50 g / 10 min, preferably 1 to 10 g / 10 min. If the melt index is less than 1 g / 10 min, the resin flow characteristics in the extrusion process may be deteriorated and it may be difficult to maintain the above-mentioned intrinsic viscosity ratio at the optimum condition of 0.5 to 1, and if it exceeds 50 g / 10 min The molecular weight may be lowered and the impact resistance characteristic of the final product may be deteriorated.

The ethylene propylene block copolymer resin composition according to the present invention may further contain additives or solvents known in the art within the scope of not impairing the object of the present invention. For example, an antioxidant, a catalyst neutralizing agent, a pigment, a dispersant, a lubricant, an antistatic agent, a UV stabilizer, a slip agent, an anti-blocking agent, talc and the like may be added. The additive can be appropriately adjusted by those skilled in the art to the extent that the object of the present invention is not impaired.

The ethylene propylene block copolymer resin composition according to the present invention is not particularly limited. For example, the above-mentioned components and other additives may be kneaded, kneaded, A kneader such as a Banbury mixer or a single screw / twin screw extruder, and then kneading the charged raw materials by using the apparatuses.

According to one embodiment of the present invention, there is provided a molded article produced by using an ethylene propylene block copolymer resin composition, wherein the molded article can be obtained by molding the resin composition of the present invention in an arbitrary manner such as extrusion, blow molding, film molding, But the present invention is not limited thereto. The molded article may be, for example, a refrigerated container, a freezing container, a multi-purpose storage container, an automobile interior / exterior material, a food packaging container, a bottle cap, a packaging film, a protective film, a decor sheet, a retort pouch, no.

Example  One

Propylene was injected into the reaction apparatus and subjected to bulk polymerization to prepare a crystalline propylene homopolymer. A series of reaction apparatuses were subjected to a gas phase reaction in the presence of a crystalline propylene homopolymer so that the domain size was 100 to 200 nm in average diameter and the ethylene content in the ethylene propylene rubber was 60 wt% The ethylene propylene block copolymer obtained by kneading the crystalline propylene homopolymer and the ethylene propylene rubber in such a manner that the content ratio of the homopolymer and the ethylene propylene rubber was 93 wt% and 7 wt%, respectively, and the intrinsic viscosity ratio was 0.8, Lt; / RTI >

Example  2

In Example 1, the ethylene content in the ethylene propylene rubber was adjusted to 50 wt%, the domain size of the ethylene propylene rubber was 200 to 300 nm in average diameter, the content ratio of the crystalline propylene homopolymer to the ethylene propylene rubber was 94 wt% %, And 6 wt%, respectively, and the intrinsic viscosity ratio was 1. The ethylene propylene block copolymer was prepared in the same manner as in Example 1 except that the amount of polymerization in each step was controlled.

Example  3

In Example 1, the ethylene content in the ethylene propylene rubber was adjusted to 45 wt%, and the contents of the crystalline propylene homopolymer and the ethylene propylene rubber were adjusted to 90 wt% and 10 wt%, respectively, so that the intrinsic viscosity ratio was 0.7. An ethylene propylene block copolymer was prepared in the same manner as in Example 1 except that the amount of polymerization was controlled.

Comparative Example  One

In Example 1, the ethylene content in the ethylene propylene rubber was adjusted to 50 wt%, and the contents of the crystalline propylene homopolymer and the ethylene propylene rubber were adjusted to 97 wt% and 3 wt%, respectively, so that the intrinsic viscosity ratio was 0.9. An ethylene propylene block copolymer was prepared in the same manner as in Example 1 except that the amount of polymerization was controlled.

Comparative Example  2

In Example 1, the ethylene content in the ethylene propylene rubber was adjusted to 45 wt%, and the contents of the crystalline propylene homopolymer and the ethylene propylene rubber were 83 wt% and 17 wt%, respectively, so that the intrinsic viscosity ratio was 0.8. An ethylene propylene block copolymer was prepared in the same manner as in Example 1 except that the amount of polymerization was controlled.

Comparative Example  3

In Example 1, the ethylene content in the ethylene propylene rubber was adjusted to 75 wt%, the domain size of the ethylene propylene rubber was made 700 to 800 nm in average diameter, the content ratio of the crystalline propylene homopolymer to the ethylene propylene rubber was 90 wt% %, And 10 wt%, respectively, and the polymerization degree of each step was adjusted so that the intrinsic viscosity ratio was 0.9. The ethylene propylene block copolymer was prepared in the same manner as in Example 1.

Comparative Example  4

An ethylene propylene block copolymer was obtained in the same manner as in Example 1, except that the ethylene propylene rubber in Example 1 had an average diameter of 200 to 300 nm and an intrinsic viscosity ratio of 1.5, .

Experimental Example

A phenol-based antioxidant, a phosphate-based antioxidant and a calcium stearate as a catalyst neutralizing agent were added to the ethylene propylene block copolymer prepared according to the above Examples and Comparative Examples and melt-mixed at 220 ° C through a twin-screw extruder to form a pellet. To prepare a polypropylene resin composition. Then, test specimens of the prepared compositions were prepared and analyzed and evaluated in the following manner. The results are shown in Table 1 below.

[Method of analyzing resin composition]

(1) Ethylene content: Ethylene content was measured using a 720, 740 cm ^-1 characteristic peak using an infrared absorption spectrum (FT-IR).

(2) Melting point (Tm): 10 mg of the test piece was pre-melted at 220 캜 for 5 minutes under a nitrogen gas atmosphere using a differential scanning calorimeter (trade name DSC, Perkin-Elmer Co.) Deg.] C to 40 [deg.] C at a heating rate of 5 [deg.] C / min. Thereafter, the temperature was raised at a heating rate of 5 DEG C / min, and the peak temperature of the maximum peak of the obtained melting endothermic curve was defined as the melting point (Tm). The melting point of indium (In) measured by using the above-described measuring apparatus at a heating rate of 5 占 폚 / min is 156.6 占 폚.

(3) Intrinsic viscosity ratio: The solvent extract of the ethylene propylene rubber (b) shows a component soluble in 150 ml of xylene solvent in 200 ml of the polypropylene block copolymer, and the crystalline propylene homopolymer (a) It indicates a component that is not soluble in phenol solvent. The intrinsic viscosity of each component was measured using a viscosity meter under a decalin solution at 135 ° C for the solvent extract obtained using the xylene solvent. The intrinsic viscosity ratio was calculated according to the following equation (1).

[Equation 1]

Intrinsic viscosity ratio = intrinsic viscosity of amorphous ethylene propylene rubber (b) / intrinsic viscosity of crystalline propylene homopolymer (a)

(4) Domain Size (EPR Domain Size): The cross section of ethylene propylene block copolymer specimen was cut at low temperature and ethylene propylene rubber was selectively etched in the xylene solvent, and the cross-section of the insoluble crystalline propylene homopolymer was confirmed Respectively.

[Property evaluation method]

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

(2) Degree of cloudiness: The degree of cloudiness of a 60 mu m film was measured according to ASTM D1003.

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

(4) Izod and Dupont impact strength: measured at room temperature (23 ° C) and low temperature (-10 ° C) according to ASTM D256 method.

(5) Heat distortion temperature: Measured according to the ASTM D648 method.

(6) Poling dart impact strength: A 60 탆 film was measured according to the ASTM D4226 method.

(7) Heat-bonding strength: After laminating a polypropylene film (60 占 퐉), an aluminum foil (9 占 퐉), Nylon (15 占 퐉) and PET (12 占 퐉), the sheet was bonded for 1 second under a pressure of 2 kgf / . The formed film was cut into a width of 25 mm and the peel strength at a peel angle of 180 占 was measured at a peel rate of 200 mm / min at 23 占 폚.

(8) Fish eye (F / E): The transmitted F / E was detected by transmitting light through the molded film, and F / E per standard area (600 cm2) Were counted and quantified.

Referring to Table 1, according to the present invention, an amorphous ethylene propylene rubber (EPR) having an optimum content is gradually polymerized to a crystalline propylene homopolymer, and the optimal intrinsic viscosity ratio and domain size control are performed, It is possible to manufacture an ethylene propylene block copolymer resin which is excellent in heat resistance and satisfies both transparency and impact resistance at the same time.

On the other hand, when the amorphous ethylene propylene rubber content did not fall within the optimum range (Comparative Example 1), the impact resistance was lowered. When the content was excessive (Comparative Example 2), transparency and thermal adhesion properties were deteriorated, . Also, when the domain size of the amorphous ethylene propylene rubber was not controlled to an optimum range (Comparative Example 3), transparency, heat bonding property and appearance property were not satisfactory, and when the ratio was outside the optimum intrinsic viscosity ratio (Comparative Example 4) And the characteristics are deteriorated.

The preferred embodiments of the present invention have been described in detail with reference to the drawings. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

Therefore, the scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning, range, and equivalence of the claims are included in the scope of the present invention. .

Claims (6)

from 5 to 15% by weight of an amorphous ethylene propylene rubber (EPR) comprising 85 to 95% by weight of a crystalline propylene homopolymer and 40 to 70% by weight of ethylene, Wherein the ethylene-propylene block copolymer resin composition comprises:
The intrinsic viscosity ratio of the amorphous ethylene propylene rubber (b) to the crystalline propylene homopolymer (a) is 0.5 to 1,
The amorphous ethylene propylene rubber (b) has an average diameter of 100 to 500 nm. delete delete The method according to claim 1,
Wherein the resin composition further comprises at least one additive selected from the group consisting of an antioxidant, a catalyst neutralizer, a pigment, a dispersant, a lubricant, an antistatic agent, a UV stabilizer, a slip agent, an anti- Propylene block copolymer resin composition. A molded article produced from the resin composition of any one of claims 1 to 4. 6. The method of claim 5,
Characterized in that the molded article is any one of a refrigerated container, a freezing container, a multipurpose container, an automobile interior / exterior material, a food packaging container, a bottle cap, a film for packaging, a protective film, a decor sheet, a retort pouch, .