KR102078926B1 - Polypropylene resin composition with excellent transparency and tear strength - Google Patents

Abstract

A polypropylene resin composition according to an embodiment of the present invention is not only excellent in processability, but also excellent in transparency and tear strength of a film produced therefrom, and thus is suitable for an agricultural reflective film. The polypropylene resin composition comprises: 70 to 90 wt% of a polypropylene resin and 10 to 30 wt% of an ethylene-propylene rubber copolymer resin.

Description

Polypropylene resin composition with excellent transparency and tear strength}

The present invention relates to a polypropylene resin composition excellent in transparency and tear strength. Specifically, the present invention relates to a polypropylene resin composition which is excellent in transparency and tear strength and suitable for use in agricultural reflective films.

Agricultural reflecting film reflects sunlight from the ground, so that the sunlight is evenly irradiated on the bottom of the crop, which is shaded by the branches or leaves of the crop, thereby preventing the problem of inhibiting the growth of fruit trees or deteriorating sugar and coloring. .

As the agricultural reflective film, a deposition film formed by depositing aluminum on a uniaxial or biaxially stretched polypropylene film or a polyester film has been used, but these films have a disadvantage in that they are easily torn in the machine direction (MD).

In order to solve such a problem, Korean Patent Application Publication No. 2011-0083774 discloses a film selected from an unstretched polyester film, a linear low density polyethylene film, and a high density polyethylene film is bonded to an unstretched polypropylene film on which aluminum is deposited. Korean Patent Application Publication No. 2011-0083775 discloses a uniaxial or biaxially stretched polypropylene film or an unstretched polypropylene film on which aluminum is deposited, an unstretched polyester film, a linear low density polyethylene film, and a high density polyethylene. Disclosed is a reflective film in which a film selected from films is bonded.

In addition, Korean Patent No. 1507326 discloses a reflective film in which a thin aluminum layer is formed on at least one surface of a base film made of a polypropylene resin and a metallocene polyethylene resin.

However, these reflecting films still have the drawback that the tear strength is not sufficient to easily tear in the longitudinal direction of the film upon falling.

Korean Patent Application Publication No. 2011-0083774 Korean Patent Application Publication No. 2011-0083775 Republic of Korea Patent No. 1507326

Accordingly, it is an object of the present invention to provide a polypropylene resin composition which is excellent in transparency and glossiness, and excellent in tear strength, suitable for use as an agricultural reflective film.

According to one embodiment of the present invention for achieving the above object, based on the total weight of components (A) and (B), (A) having an ethylene-propylene random copolymer and an ethylene-propylene copolymer in the dispersed phase 70 to 90% by weight of at least one polypropylene resin selected from the group consisting of polypropylene block copolymers and 10 to 30% by weight of (B) ethylene-propylene rubber copolymer resin, but at 230 ° C. with a 2.16 kg load. In the measurement, the melt index of the ethylene-propylene random copolymer was 6.0 to 8.0 g / 10 minutes, the melt index of the polypropylene block copolymer having the ethylene-propylene copolymer as the dispersed phase was 4.0 to 6.0 g / 10 minutes, and the load was 2.16 kg. The polypropylene resin composition having a melt index of 2.0 ~ 4.0 g / 10 minutes of ethylene-propylene rubber copolymer resin as measured at 190 ℃.

Preferably, the content of the polypropylene resin (A) is 70 to 80% by weight, and the content of the ethylene-propylene rubber copolymer resin (B) is 20 to 30% by weight.

The ethylene content in the ethylene-propylene random copolymer is 2.0 to 4.0% by weight, and the ethylene content in the polypropylene block copolymer having the ethylene-propylene copolymer as the dispersed phase is 8.0 to 10.0% by weight.

Moreover, the content of the solvent extract in the polypropylene block copolymer which has an ethylene propylene copolymer as a dispersed phase is 18.0-20.0 weight%.

On the other hand, the ethylene content of the ethylene-propylene rubber copolymer resin is 65 to 75 mol%, the intrinsic viscosity is 1.0 to 2.0, the content of the solvent extract is 85 to 95% by weight.

The polypropylene resin composition according to an embodiment of the present invention comprises at least one additive selected from the group consisting of antioxidants, processing lubricants, reinforcements, fillers, weather stabilizers, antistatic agents, slip agents, nucleating agents, flame retardants, pigments and dyes. It may further include.

Specifically, the polypropylene resin composition according to the embodiment of the present invention is based on 100 parts by weight of this composition, tetrakis (methylene (3,5-di-t-butyl-4-hydroxy) hydrosilylate), 1, At least one selected from the group consisting of 3,5-trimethyl-tris (3,5-di-t-butyl-4-hydroxy benzene) and tris (2,4-di-t-butylphenyl) phosphite The antioxidant may further comprise 0.05 to 0.2 parts by weight.

In addition, the polypropylene resin composition according to the embodiment of the present invention is 0.05 to 0.2 weight of one or more processing lubricants selected from the group consisting of calcium stearate, magnesium stearate and combinations thereof based on 100 parts by weight of the composition. It may further include wealth.

The polypropylene resin composition according to the embodiment of the present invention is not only excellent in workability, but also excellent in transparency and tear strength of the film produced therefrom, and thus is suitable for an agricultural reflective film.

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

Polypropylene resin composition according to an embodiment of the present invention, based on the total weight of the component (A) and component (B), (A) a poly having a ethylene-propylene random copolymer and ethylene-propylene copolymer in the dispersed phase 70-90% by weight of at least one polypropylene resin selected from the group consisting of propylene block copolymers and (B) 10-30% by weight of ethylene-propylene rubber copolymer resin, measured at 230 ° C. with a 2.16 kg load Melt index of polypropylene block copolymer having a ethylene-propylene copolymer in the dispersing phase is 6.0 to 8.0 g / 10 minutes, and 4.0 to 6.0 g / 10 minutes. The melt index of the ethylene-propylene rubber copolymer resin when measured at 190 ° C. is 2.0 to 4.0 g / 10 min.

In the polypropylene resin composition according to one embodiment of the present invention, the polypropylene resin (A) constituting the continuous phase is at least one of a polypropylene block copolymer having an ethylene-propylene random copolymer and an ethylene-propylene copolymer in a dispersed phase. It is one resin.

The content of at least one polypropylene resin (A) selected from the polypropylene block copolymer having the ethylene-propylene random copolymer and the ethylene-propylene copolymer as the dispersed phase in the polypropylene resin composition according to one embodiment of the present invention is 70 90 wt%, preferably 70-80 wt%.

When the content of the polypropylene resin (A) in the polypropylene resin composition according to an embodiment of the present invention is less than 70% by weight, the processability of the film may be lowered when processing the film from the polypropylene composition, and the film produced therefrom Transparency may not be sufficient. On the other hand, when the content of the polypropylene resin (A) exceeds 90% by weight, the content of the rubber component in the polypropylene composition is low, so that the improvement in tear strength of the film produced therefrom may not be sufficient.

On the other hand, the melt index of the ethylene-propylene random copolymer was 6.0-8.0 g / 10 min, measured at 230 ° C with a 2.16 kg load in accordance with ASTM D1238, of the polypropylene block copolymer having the ethylene-propylene copolymer in the dispersed phase. Melt index is 4.0-6.0 g / 10 min. The higher the melt index, the better the processability of the polypropylene composition. However, if the melt index exceeds the upper limit of each of the above ranges, the mechanical properties such as tear strength of agricultural reflective films produced therefrom may be deteriorated. not.

In addition, the ethylene content in the ethylene-propylene random copolymer is 2.0 to 4.0% by weight, and the ethylene content in the polypropylene block copolymer having the ethylene-propylene copolymer as the dispersed phase as the dispersed phase is 6.0 to 10.0% by weight. May be%. When the upper limit of this range is exceeded, mechanical properties such as tear strength of the film may deteriorate, which is not preferable.

In addition, the content of the solvent extract in the polypropylene block copolymer having the ethylene-propylene copolymer as the dispersed phase may be 18.0 to 20.0 wt%. When the upper limit of this range is exceeded, an excessive dispersion phase may aggregate and the impact resistance of a film may worsen, which is not preferable.

Examples of commercially available polypropylene resins (A) include RF401 (ethylene-propylene random copolymer consisting of 98% by weight of propylene and 2% by weight of ethylene; Total Hanwha), RF402 (97% by weight of propylene and 3% by weight of ethylene) Ethylene-propylene random copolymer; Hanwha Total), CF309 (polypropylene block copolymer composed of 94% by weight of propylene and 6% by weight of ethylene and having ethylene-propylene copolymer as dispersed phase; Hanwha Total) and CF330 (91% by weight of propylene) % And ethylene 9% by weight, polypropylene block copolymer having a ethylene-propylene copolymer in the dispersed phase; Hanwha Total) and the like, but is not limited thereto.

In the polypropylene resin composition according to one embodiment of the present invention, the resin (B) constituting the rubber phase is an ethylene-propylene rubber copolymer resin.

The content of the ethylene-propylene rubber copolymer resin (B) in the polypropylene resin composition according to one embodiment of the present invention is 10 to 30% by weight, preferably 20 to 30% by weight.

If the content of the ethylene-propylene rubber copolymer resin (B) in the polypropylene resin composition according to one embodiment of the present invention is less than 10% by weight, the tearing strength of the film produced from the polypropylene composition due to the low content of the rubber component May not be sufficient. On the other hand, when the content of the ethylene-propylene rubber copolymer resin (B) exceeds 30% by weight, the processability of the film during film processing from this polypropylene composition may decrease, and the transparency of the film produced therefrom may not be sufficient. Can be.

On the other hand, the melt index of ethylene-propylene rubber copolymer resin (B) is 2.0-4.0 g / 10min when measured at 190 degreeC by 2.16 kg load based on ASTMD1238. The higher the melt index, the better the processability of the polypropylene composition. However, if the melt index exceeds the upper limit of the above range, mechanical properties such as tear strength of agricultural reflective films produced therefrom may be deteriorated. .

Moreover, ethylene content in ethylene propylene rubber copolymer resin (B) is 65-75 mol%. If the upper limit of this range is exceeded, the compatibility of the continuous polypropylene resin is deteriorated and mechanical properties such as tear strength of the film may deteriorate, which is not preferable.

In addition, the intrinsic viscosity of the ethylene-propylene rubber copolymer resin (B) may be 1.0 to 2.0. When the upper limit of this range is exceeded, extrusion processability of the resin composition is bad, which is not preferable.

In addition, the content of the solvent extract in the ethylene-propylene rubber copolymer resin (B) may be 85 to 95% by weight. At this time, xylene is preferable as the solvent for measuring the solvent extract. If it is less than this lower limit, the impact resistance of the film is bad, which is not preferable.

Examples of commercially available ethylene-propylene rubber copolymer resins (B) include, but are not limited to, Versify (Dow), Vistamaxx (ExxonMobil), Tafmer (Mitsui), KEP (Kumho Petrochemical), etc. no.

The polypropylene resin composition according to the embodiment of the present invention may further include conventional additives within a range not departing from the scope of the present invention. For example, the polypropylene resin composition may further include one or more additives selected from the group consisting of antioxidants, processing lubricants, reinforcements, fillers, weather stabilizers, antistatic agents, slip agents, nucleating agents, flame retardants, pigments and dyes. May be, but is not limited to these.

Preferably, the polypropylene resin composition according to the embodiment of the present invention may further include an antioxidant. For example, the antioxidant may be at least one selected from the group consisting of phenolic antioxidants, phosphite antioxidants, thiodipropionate antioxidants, and combinations thereof. Specifically, tetrakis (methylene (3,5-di-t-butyl-4-hydroxy) hydrosilylate), 1,3,5-trimethyl-tris (3,5-di-t-butyl-4- Hydroxy benzene) and tris (2,4-di-t-butylphenyl) phosphite, but may be one or more selected from the group consisting of, but not limited thereto.

At this time, the antioxidant may be added in an amount of 0.05 to 0.2 parts by weight, preferably 0.05 to 0.1 parts by weight based on 100 parts by weight of the polypropylene resin composition. If the content of the antioxidant is less than 0.05 part by weight, it is difficult to secure the antioxidant effect of the polypropylene composition, and if the content of the antioxidant is more than 0.2 part by weight, the antioxidant may be eluted or the economical efficiency of the product is not preferable. .

Preferably, the polypropylene resin composition according to the embodiment of the present invention may further include a processing lubricant. For example, the processing lubricant may be, but is not limited to, one or more selected from the group consisting of calcium stearate, magnesium stearate, and combinations thereof.

In this case, the processing lubricant may be added in an amount of 0.05 to 0.2 parts by weight, preferably 0.05 to 0.1 parts by weight based on 100 parts by weight of the polypropylene resin composition. When the content of the processing lubricant is less than 0.05 parts by weight, it is difficult to secure the processability improvement effect of the polypropylene composition, and when the content of the processing lubricant exceeds 0.2 parts by weight, the processing lubricant may be eluted or the economical efficiency of the product may not be preferable. .

The method for producing the polypropylene resin composition according to the embodiment of the present invention is not particularly limited. Preferably, blending the ethylene-propylene rubber copolymer resin (B) with at least one polypropylene resin (A) selected from an ethylene-propylene random copolymer and a polypropylene block copolymer having an ethylene-propylene copolymer in the dispersed phase Can be prepared.

At this time, there is no particular limitation on the blending method of the two resins, and the blending method known in the art to which the present invention pertains may be used as it is or as appropriately modified. For example, each of the above-mentioned resins and, if necessary, additives are added to kneaders, rolls, Banbury mixers, kneaders or single screw twin screw extruders, and then used. The polypropylene resin composition of the present invention can be prepared by a method of blending the inputted raw materials.

Example

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

The resin used in the following Examples and Comparative Examples is as follows.

A1: Ethylene-propylene random copolymer (RF401, Hanwha Total) having a melt index of 7 g / 10 minutes and an ethylene content of 2.5% by weight

A2: Ethylene-propylene block copolymer (CF330, Hanwha Total) having a melt index of 5 g / 10 minutes, an ethylene content of 9% by weight, a solvent extract content of 19% by weight, and an ethylene-propylene copolymer as a dispersed phase.

A3: Crystalline ethylene-propylene block copolymer having a melt index of 5 g / 10 minutes (BF200, Hanwha Total)

B1: ethylene-propylene random rubber copolymer (melt index 3.2 g / 10 min (190 DEG C), intrinsic viscosity 1.4, ethylene content 75 mol%, solvent extract content 90 wt%)

B2: ethylene-butene random rubber copolymer, melt index 3.0 g / 10 min (190 ° C)

B3: ethylene-octene random rubber copolymer, melt index 4.5 g / 10 min (190 ° C)

The composition and physical properties of the above resins were measured by the following method.

(1) Melt Index

It was measured at 230 ° C. (resin A) or 190 ° C. (resin B) with a load of 2.16 kg according to the method of ASTM D 1238.

(2) content of solvent extract (xylene soluble)

Each resin was dissolved in xylene at a concentration of 1% by weight at 140 ° C. for 1 hour, and after 2 hours at room temperature, the extracted weight was measured and expressed as a percentage of the total weight of the resin.

(3) intrinsic viscosity

The intrinsic viscosity of each resin was measured in a decalin solvent at 135 ° C. using a viscometer.

(4) Ethylene Content (wt%) in the Ethylene-propylene Block Copolymer

The ethylene-propylene block copolymer was dissolved in xylene, and the extracted component (xylene extract) was analyzed by infrared absorption spectrum, and the characteristic peaks of 720 cm ^-1 and 740 cm ^-1 were used in the ethylene-propylene block copolymer component. The content of ethylene was measured.

(5) Ethylene content (mol%) in ethylene-propylene rubber copolymer resin

Similarly to the measurement method of (4) above, the ethylene-propylene rubber copolymer was extracted with xylene, and the ethylene content in the ethylene-propylene rubber copolymer component was measured in an infrared absorption spectrum, and this was converted in mole%.

Examples 1-4

Each content of the polypropylene resin (A) and the ethylene-propylene rubber copolymer resin (B) of the polypropylene block copolymer having an ethylene-propylene random copolymer or an ethylene-propylene copolymer in the dispersed phase, as shown in Table 1 below. By mixing using a single screw extruder. At this time, the cylinder temperature was adjusted to 150 ° C to 220 ° C, and kneaded under an extrusion amount of 30 kg / hour and a screw speed of 250 rpm to prepare a polypropylene resin composition.

Comparative example  1 to 4

According to the composition and content of Table 1 below, a polypropylene resin composition was prepared in the same manner as in Example 1.

weight% Example Comparative example One 2 3 4 One 2 3 4 Resin (A) A1 A2 A1 A2 A3 A1 A1 A1 80 80 75 75 80 80 80 65 Resin (B) B1 B1 B1 B1 B1 B2 B3 B1 20 20 25 25 20 20 20 35

Test Example

After evaluating the resin compositions obtained in the Examples and Comparative Examples using the DR COLLIN 3-layer unstretched film maker, the films for evaluation were measured, and then the physical properties of the obtained film specimens were measured according to the following measurement method. Table 2 shows.

(1) Falling Impact Strength

The film extruded to a thickness of 25 μm was cut into 20 cm and 20 cm lengths, and the minimum weight at which the film was broken was evaluated by dropping an iron hole at a height of 1 m.

(2) tear strength

Elemendorf tear strength was measured in the machine direction (MD) of the film according to ASTM D1922.

(3) haze (blur,%)

The film extruded to the thickness of 25 micrometers was cut | disconnected by 20 cm and 20 cm, and haze was measured by ASTM1004 specification.

(4) glossiness

According to ASTM D 2457, the light source was measured at an angle of 60 ° from the film surface.

(5) processability

The surface quality (die line, thickness deviation) was evaluated, while extruding the resin composition to a thickness of 25 μm.

Example Comparative example One 2 3 4 One 2 3 4 Falling Impact Strength (g) 433 599 494 672 788 591 772 424 Tear strength (N / mm) 133 177 145 180 77 43 74 130 Haze (%) 2.4 3.7 2.8 4.2 12.2 4.3 2.4 8.0 Glossiness (60 °) 80 78 78 74 52 80 83 44 Machinability Good Good Good Good Good Good Good Bad

As can be seen from Table 2, the polypropylene resin compositions of Examples 1 to 4 belonging to the scope of the present invention are excellent in workability, and have fallen impact strength, tear strength, haze (blur), and the like. The gloss was all excellent.

On the other hand, the composition of Comparative Example 1 using the crystalline ethylene-propylene block copolymer as the continuous polypropylene resin did not have good tear strength, haze and glossiness of the film. In addition, Comparative Examples 2 and 3 in which the ethylene-butene random rubber copolymer and the ethylene-octene random rubber copolymer were used as the rubbery components, respectively, did not have good tear strength of the film. In the case of Comparative Example 4 in which the contents of the polypropylene resin (A) and the ethylene-propylene rubber copolymer resin (B) were out of the range of the present invention, the haze and glossiness of the film were not good.

Polypropylene resin composition according to the embodiment of the present invention is excellent in transparency and gloss, but also excellent in tear strength is suitable for use as an agricultural reflective film.

Claims (8)

At least one selected from the group consisting of (A) an ethylene-propylene random copolymer and a polypropylene block copolymer having a ethylene-propylene copolymer in the dispersed phase based on the total weight of components (A) and (B) 70 to 90% by weight of polypropylene resin and 10 to 30% by weight of (B) ethylene-propylene rubber copolymer resin,
Melt index of ethylene-propylene random copolymer is 6.0-8.0 g / 10min, and melt index of polypropylene block copolymer having ethylene-propylene copolymer as dispersed phase is measured at 230 ℃ with 2.16 kg load. 10 minutes, polypropylene resin composition characterized in that the melt index of the ethylene-propylene rubber copolymer resin is 2.0 ~ 4.0 g / 10 minutes when measured at 190 ℃ with a 2.16 kg load.
The polypropylene resin composition according to claim 1, wherein the content of the polypropylene resin (A) is 70 to 80% by weight and the content of the ethylene-propylene rubber copolymer resin (B) is 20 to 30% by weight.
The ethylene content in the ethylene-propylene random copolymer is 2.0 to 4.0% by weight, and the ethylene content in the polypropylene block copolymer having the ethylene-propylene copolymer as a dispersed phase is 8.0 to 10.0% by weight. Polypropylene resin composition.
The polypropylene resin composition according to claim 1, wherein the content of the solvent extract in the polypropylene block copolymer having the ethylene-propylene copolymer in the dispersed phase is 18.0 to 20.0 wt%.
The polypropylene resin according to claim 1, wherein the ethylene content of the ethylene-propylene rubber copolymer resin is 65 to 75 mol%, the intrinsic viscosity is 1.0 to 2.0, and the content of the solvent extract is 85 to 95 wt%. Composition.
The method of claim 1, further comprising at least one additive selected from the group consisting of antioxidants, processing lubricants, reinforcing agents, fillers, weather stabilizers, antistatic agents, slip agents, nucleating agents, flame retardants, pigments and dyes. Polypropylene resin composition.
The tetrakis (methylene (3,5-di-t-butyl-4-hydroxy) hydrosilylate) and 1,3,5-trimethyl-tris according to claim 6, based on 100 parts by weight of the polypropylene resin composition. 0.05 to 0.2 parts by weight of one or more antioxidants selected from the group consisting of (3,5-di-t-butyl-4-hydroxy benzene) and tris (2,4-di-t-butylphenyl) phosphite It further comprises a polypropylene resin composition.
The method according to claim 6, further comprising 0.05 to 0.2 parts by weight of one or more processing lubricants selected from the group consisting of calcium stearate, magnesium stearate and combinations thereof based on 100 parts by weight of the polypropylene resin composition. Polypropylene resin composition.