KR20230100267A - Polyethylene resin composition and molded article manufactured using the same - Google Patents

Abstract

(A) 20% to 80% by weight of a first polyethylene resin having a molecular weight distribution (Mw/Mn) of greater than 3 and less than 10; and (B) 20% to 80% by weight of a second polyethylene resin having a molecular weight distribution (Mw/Mn) of 10 or more to less than 50, and among the first polyethylene resin (A) and the second polyethylene resin (B) At least one relates to a polyethylene resin composition comprising a recycled resin obtained from polyethylene resin-derived waste and a molded article manufactured therefrom.

Description

Polyethylene resin composition and molded article manufactured therefrom {POLYETHYLENE RESIN COMPOSITION AND MOLDED ARTICLE MANUFACTURED USING THE SAME}

It relates to a polyethylene resin composition and a molded article prepared therefrom.

Blow molding is a representative method of forming a container, and research has been actively conducted to enhance appearance, rigidity, impact resistance, and the like.

For example, in Korean Patent Publication No. 10-2007-0128626, the melt flow index under high load is 5.0 g/10 min or less, the weight average molecular weight is 250,000 g/mol to 450,000 g/mol, the molecular weight distribution is 12 to 25, the melting A flow index ratio MI _21.6 / MI _2.16 is 50 to 200, and an antioxidant is applied to a polyethylene resin having a density of 0.95 g / cm 3 or more, and a material having excellent drop impact resistance, loading strength, and appearance is disclosed. In addition, in Korean Patent Publication No. 10-2015-0135251, a weight average molecular weight of 350,000 g / mol to 400,000 g / mol, a molecular weight distribution of 12 to 25, and a density of 0.954 g, prepared by a Ziegler-Natta catalyst and a multimodal process / cm 3 to 0.960 g / cm 3, and the melt flow index of 0.10 g / 10 minutes to 0.16 g / 10 minutes through a material to ensure stiffness, impact resistance, resistance to environmental stress cracking.

On the other hand, recently, as the environmental problems of plastics have been highlighted, various studies for eco-friendliness are in progress. Environmentally friendly plastics include methods such as physical recycling, chemical recycling, and the use of biodegradable plastics. Among them, physical recycling means mixing recycled resin with new materials for use. In general, since the physical properties of recycled resin are inferior to those of new materials, research on resin compositions expressing physical properties similar to those of new materials while applying recycled resins has been reported.

For example, Korean Patent Publication No. 10-2011-0120760 discloses an appropriate number and content of regeneration of a regenerated high-density polyethylene resin capable of expressing physical properties similar to those of a new crystalline high-density polyethylene resin. However, the applied regenerated high-density polyethylene resin is a re-extruded crystalline high-density polyethylene resin, and there is no mention of a case in which a regenerated resin different from the composition of the new material is applied.

Therefore, it is necessary to develop an eco-friendly polyethylene resin composition suitable for hollow molding without inferior physical properties compared to new materials by using recycled resin having a different composition from new materials.

Korean Patent Publication No. 10-2007-0128626 Korean Patent Publication No. 10-2015-0135251 Korean Patent Publication No. 10-2011-0120760

One embodiment provides a polyethylene resin composition that is environmentally friendly and has excellent rigidity, blow moldability, and impact resistance while including recycled resin.

Another embodiment provides a molded article prepared from the polyethylene resin composition.

One embodiment is (A) 20% to 80% by weight of a first polyethylene resin having a molecular weight distribution (Mw/Mn) of greater than 3 and less than 10; and (B) 20% to 80% by weight of a second polyethylene resin having a molecular weight distribution (Mw/Mn) of 10 or more to less than 50, and among the first polyethylene resin (A) and the second polyethylene resin (B) At least one provides a polyethylene resin composition comprising a recycled resin obtained from polyethylene resin-derived waste.

The first polyethylene resin (A) may include at least one selected from the group consisting of a polyethylene resin and a recycled resin obtained from waste derived from the polyethylene resin, wherein the polyethylene included as the first polyethylene resin (A) The resin and the polyethylene resin in the polyethylene resin-derived waste may be polymerized in a single reactor or two or more reactors, respectively.

The second polyethylene resin (B) may include at least one selected from the group consisting of a polyethylene resin and a recycled resin obtained from waste derived from the polyethylene resin, wherein the polyethylene included as the second polyethylene resin (B) The resin and the polyethylene resin in the polyethylene resin-derived waste may each be polymerized in two or more reactors.

The melt flow index (2.16kg, 190°C) of the first polyethylene resin (A) may be 0.1 g/10 min to 20 g/10 min.

The melt flow index (2.16kg, 190°C) of the second polyethylene resin (B) may be 0.01 g/10 min to 0.5 g/10 min.

The polyethylene resin composition may have a melt flow index (2.16kg, 190°C) of 0.1 g/10 min to 0.5 g/10 min.

The polyethylene resin composition may have a density of 0.950 g/cm ³ to 0.970 g/cm ³ .

Izod impact strength of the polyethylene resin composition may be 20 kgf cm/cm to 50 kgf cm/cm.

Another embodiment provides a molded article prepared from the polyethylene resin composition.

According to one embodiment, it is possible to secure an environment-friendly polyethylene resin composition that has excellent impact resistance, excellent stiffness and blow moldability similar to that of new materials, and uses only a small amount of new materials while using recycled resin. Accordingly, it can be usefully used for molded articles suitable for blow molding.

Hereinafter, embodiments will be described in detail so that those skilled in the art can easily implement them. However, implementations may take many different forms and are not limited to the implementations described herein.

The polyethylene resin composition according to one embodiment includes (A) a first polyethylene resin having a molecular weight distribution (Mw/Mn) of greater than 3 to less than 10 and (B) a second polyethylene resin having a molecular weight distribution (Mw/Mn) of 10 or more to less than 50 Including, at least one of the first polyethylene resin (A) and the second polyethylene resin (B) includes a recycled resin obtained from polyethylene resin-derived waste.

According to one embodiment, it includes a recycled resin having a different composition from the new material, and is superior in stiffness and blow moldability to a similar degree to that of the new material compared to the case where only the new material is used, and despite using the recycled resin, the impact resistance is excellent and the amount of new material used is small. An environmentally friendly polyethylene resin composition can be secured. Accordingly, it can be usefully used for molded articles suitable for blow molding.

Hereinafter, the said 1st polyethylene resin (A) is demonstrated.

The first polyethylene resin (A) may have a molecular weight distribution (Mw/Mn) of greater than 3 to less than 10, for example, 3.1 or more to less than 10, 3.2 or more to less than 10, 3.3 or more to less than 10, or 3.4 or more to less than 10. It may be less than 10, 3.5 or more to less than 10. The molecular weight distribution (Mw/Mn) is a value obtained by dividing the weight average molecular weight (Mw) by the number average molecular weight (Mn). When the molecular weight distribution of the first polyethylene resin (A) is within the above range, impact properties of the polyethylene resin composition may be improved.

The first polyethylene resin (A) may include at least one selected from the group consisting of a polyethylene resin and a recycled resin. According to one embodiment, at least one of the first polyethylene resin (A) and the second polyethylene resin (B) includes a recycled resin. In other words, for example, when the polyethylene resin is used as the first polyethylene resin (A), the second polyethylene resin (B) having a different molecular weight distribution (Mw/Mn) from the first polyethylene resin (A) is a recycled resin. can be used

The polyethylene resin is a new material distinct from recycled resin, and polymerized in a single reactor or two or more reactors may be used.

The recycled resin may be obtained from polyethylene resin-derived waste. The polyethylene resin-derived waste may be pre-consumer or post-consumer waste generated by using the polyethylene resin. At this time, the polyethylene resin in the polyethylene resin-derived waste may also be polymerized in a single reactor or two or more reactors.

The method of polymerizing the polyethylene resin is not particularly limited, and for example, a bulk polymerization method, a solution polymerization method, a slurry polymerization method, a gas phase polymerization method, etc. may be used, and a batch method or Either continuous type is possible.

The melt flow index (2.16 kg, 190 ° C) of the first polyethylene resin (A) may be 0.1 g / 10 minutes to 20 g / 10 minutes, for example, 0.25 g / 10 minutes to 5 g / 10 minutes. there is. When the melt flow index of the first polyethylene resin (A) is within the above range, processability and impact properties of the polyethylene resin composition may be improved during preparation of the polyethylene resin composition.

The first polyethylene resin (A) may be included in an amount of 20 wt % to 80 wt %, for example, 30 wt % to 70 wt %, based on the total weight of the polyethylene resin composition. When the first polyethylene resin (A) is included within the above range, both blow moldability and impact properties of the polyethylene resin composition may be improved.

Hereinafter, the said 2nd polyethylene resin (B) is demonstrated.

The second polyethylene resin (B) may have a molecular weight distribution (Mw/Mn) of 10 or more to less than 50, for example, 10 or more to less than 30. When the molecular weight distribution of the second polyethylene resin (B) is within the above range, blow moldability of the polyethylene resin composition may be improved.

The second polyethylene resin (B) may include at least one selected from the group consisting of polyethylene resins and recycled resins. According to one embodiment, at least one of the first polyethylene resin (A) and the second polyethylene resin (B) includes a recycled resin. In other words, for example, when the polyethylene resin is used as the second polyethylene resin (B), the first polyethylene resin (A) having a different molecular weight distribution (Mw/Mn) from the second polyethylene resin (B) is a recycled resin. can be used

The polyethylene resin is a new material distinct from recycled resin, and polymerized in two or more reactors may be used.

The recycled resin may be obtained from polyethylene resin-derived waste. The polyethylene resin-derived waste may be pre-consumer or post-consumer waste generated by using the polyethylene resin. At this time, the polyethylene resin in the polyethylene resin-derived waste may also be polymerized in two or more reactors.

The method of polymerizing the polyethylene resin is not particularly limited, and for example, a bulk polymerization method, a solution polymerization method, a slurry polymerization method, a gas phase polymerization method, etc. may be used, and a batch method or Either continuous type is possible.

The melt flow index (2.16 kg, 190 ° C) of the second polyethylene resin (B) may be 0.01 g / 10 minutes to 0.5 g / 10 minutes, for example, 0.1 g / 10 minutes to 0.4 g / 10 minutes. there is. When the melt flow index of the second polyethylene resin (B) is within the above range, both blow moldability and impact properties of the polyethylene resin composition may be improved.

The second polyethylene resin (B) may be included in an amount of 20 wt % to 80 wt %, for example, 30 wt % to 70 wt %, based on the total weight of the polyethylene resin composition. When the second polyethylene resin (B) is included within the above content range, blow moldability, elongation, and impact properties of the polyethylene resin composition may all be improved.

The melt flow index (2.16 kg, 190 ° C) of the polyethylene resin composition according to one embodiment may be 0.1 g / 10 min to 0.5 g / 10 min, for example, 0.2 g / 10 min to 0.4 g / 10 min. can When the melt flow index of the polyethylene resin composition is within the above range, the polyethylene resin composition has excellent rigidity, blow moldability and impact properties.

The polyethylene resin composition may have a density of 0.950 g/cm ³ to 0.970 g/cm ³ , for example, 0.955 g/cm ³ to 0.965 g/cm ³ . When the density of the polyethylene resin composition is within the above range, the polyethylene resin composition has excellent rigidity, blow moldability, and impact resistance.

The Izod impact strength of the polyethylene resin composition may be 20 kgf cm/cm to 50 kgf cm/cm, for example, 20 kgf cm/cm to 40 kgf cm/cm. When the Izod impact strength of the polyethylene resin composition is within the above range, the polyethylene resin composition has excellent rigidity, blow moldability and impact properties.

The manufacturing method of the polyethylene resin composition is not particularly limited, and a manufacturing method of a polyethylene resin composition known in the art may be used as it is or modified appropriately, and each resin component described above is ordered in a desired order without any particular order limitation. You can freely choose and mix them.

For example, each of the above-mentioned resins and additives are mixed in a kneading machine such as a Henschel mixer, a kneader, a roll, or a Banbury mixer for 1 hour to 2 hours, A polyethylene resin composition in a pellet form may be prepared by melting and kneading at a temperature of 160° C. to 250° C. using a single-screw/twin-screw extruder.

According to another embodiment, a molded article manufactured from the polyethylene resin composition described above, specifically, a molded article manufactured by blow molding is provided. The molded article may be a plastic product that is environmentally friendly, has excellent impact resistance, and requires impact resistance. For example, the molded article may be selected from the group consisting of automobile interior parts, household goods, building materials, and industrial materials.

Hereinafter, specific embodiments of the present invention are presented. However, the embodiments described below are only intended to specifically illustrate or explain the present invention, and the present invention should not be limited thereto. In addition, since the content not described herein can be sufficiently technically inferred by those skilled in the art, the description thereof will be omitted.

(Production of Polyethylene Resin Composition)

(A) 1st polyethylene resin

(A1) A polyethylene resin polymerized in a single reactor, having a melt flow index of 1.1 g/10 min, and a molecular weight distribution (M _w /M _n ) of 6.5 was prepared.

(A2) A recycled resin obtained by re-extruding pre-consumer waste generated during production of separators for lithium ion batteries, which is polyethylene resin-derived waste, was prepared. The recycled resin had a melt flow index of 0.25 g/10 min and a molecular weight distribution (M _w /M _n ) of 3.5.

(B) second polyethylene resin

(B1) Polymerized through two reactors, a melt flow index of 0.35 g/10 min, and a molecular weight distribution (M _w / M _n ) of 12, a polyethylene resin (Hanwha Total) was prepared.

(B2) A recycled resin obtained by re-extruding consumer-used blow molding container waste, which is a polyethylene resin-derived waste, was prepared. The recycled resin had a melt flow index of 0.12 g/10 min and a molecular weight distribution (M _w /M _n ) of 20.

(B3) A recycled resin obtained by re-extruding consumer-used hollow molded container waste, which is polyethylene resin-derived waste, was prepared. The recycled resin had a melt flow index of 0.28 g/10 min and a molecular weight distribution (M _w /M _n ) of 13.

Examples 1 and 2 and Comparative Examples 1 to 5

A polyethylene resin composition was prepared by melt-blending and pelletizing polyethylene resin having the same type and content as shown in Table 1 below at a temperature of 230° C. in a twin-screw extruder.

(Unit: % by weight) Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 A1 50 - - - - - - A2 - 30 - 100 - - - B1 - 70 100 - - 50 80 B2 50 - - - - 50 - B3 - - - - 100 - 20

Evaluation: Physical property measurement of polyethylene resin composition

The polyethylene resin compositions prepared in Examples 1 and 2 and Comparative Examples 1 to 5 were made into extruded specimens for evaluation, and the following physical properties were measured, and the results are shown in Table 2 below.

melt flow index

It was measured with a load of 2.16 kg at 190 ° C. by the method of ASTM D 1238.

density

It was measured by the method of ASTM D 1505.

tensile strength

It was measured at room temperature by the method of ASTM D 638.

flexural modulus

It was measured according to the ASTM-4 specimen standard by the method of ASTM D 790.

Izod impact strength

It was measured according to the ASTM-4 specimen standard by the method of ASTM D 256.

blown formability

Formability was evaluated at a temperature of 180° C., which is a condition for forming a 20L container of Comparative Example 1, using a blow molding machine. If the container was molded without defects in appearance, it was evaluated as 'good', and if the container was not molded or the appearance was poor, it was evaluated as 'poor'.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Melt flow rate (g/10 min) 0.31 0.20 0.34 0.25 0.28 0.13 0.24 Density (g/cm) 0.962 0.961 0.963 0.962 0.962 0.961 0.962 Yield tensile strength (kgf/㎠) 248 269 255 254 257 262 269 Tensile strength at break (kgf/cm2) 370 385 401 50 160 361 385 Elongation at break (%) 813 913 940 21 543 728 868 Flexural modulus (kgf/㎠) 12093 12179 12552 11744 12047 12056 12547 Izod impact strength (kgf cm/cm) 26.0 32.7 18.5 48.7 14.1 18.8 18.4 blown formability Good Good Good error Good error Good

Through Table 2, the polyethylene resin compositions of Examples 1 and 2 according to one embodiment have similar stiffness and blow moldability compared to the polyethylene resin composition of Comparative Example 1 that does not contain recycled resin, even though the recycled resin is included. It can be seen that the impact resistance is excellent.

On the other hand, it can be seen that the polyethylene resin composition of Comparative Example 2 using only recycled resin having a small molecular weight distribution had excellent impact resistance, but had poor tensile strength at break, elongation at break and blow moldability. In addition, it can be seen that the polyethylene resin composition of Comparative Example 3 using only the recycled resin having a large molecular weight distribution has inferior tensile strength at break and poor impact resistance. In addition, it was found that the polyethylene resin compositions of Comparative Examples 4 and 5, in which a polyethylene resin having a large molecular weight distribution and a recycled resin having a large molecular weight distribution were mixed, had poor impact properties, and the polyethylene resin composition of Comparative Example 4 had poorer moldability. can

Therefore, the polyethylene resin composition according to one embodiment has excellent impact properties and secures hollow moldability even though it contains recycled resin, so that it can be applied as an eco-friendly hollow molded article.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and it is possible to carry out various modifications within the scope of the claims and the detailed description of the invention and the accompanying drawings, and this is also the present invention. It goes without saying that it falls within the scope of the invention.

Claims (9)

(A) 20% to 80% by weight of a first polyethylene resin having a molecular weight distribution (Mw/Mn) of greater than 3 and less than 10; and
(B) 20% to 80% by weight of a second polyethylene resin having a molecular weight distribution (Mw/Mn) of 10 or more to less than 50,
At least one of the first polyethylene resin (A) and the second polyethylene resin (B) is a polyethylene resin composition comprising a recycled resin obtained from polyethylene resin-derived waste. In paragraph 1,
The first polyethylene resin (A) includes at least one selected from the group consisting of a polyethylene resin and a recycled resin obtained from waste derived from the polyethylene resin,
The polyethylene resin composition, wherein the polyethylene resin included in the first polyethylene resin (A) and the polyethylene resin in the polyethylene resin-derived waste are polymerized in a single reactor or two or more reactors, respectively. In paragraph 1,
The second polyethylene resin (B) includes at least one selected from the group consisting of a polyethylene resin and a recycled resin obtained from waste derived from the polyethylene resin,
The polyethylene resin composition comprising the second polyethylene resin (B) and the polyethylene resin in the polyethylene resin-derived waste are polymerized in two or more reactors, respectively. In paragraph 1,
The melt flow index (2.16kg, 190 ℃) of the first polyethylene resin (A) is 0.1 g / 10 minutes to 20 g / 10 minutes polyethylene resin composition. In paragraph 1,
The melt flow index (2.16 kg, 190 ° C.) of the second polyethylene resin (B) is 0.01 g / 10 minutes to 0.5 g / 10 minutes polyethylene resin composition. In paragraph 1,
The polyethylene resin composition has a melt flow index (2.16 kg, 190 ° C) of 0.1 g / 10 minutes to 0.5 g / 10 minutes. In paragraph 1,
Density of the polyethylene resin composition is 0.950 g / cm ³ to 0.970 g / cm ³ The polyethylene resin composition. In paragraph 1,
Izod impact strength of the polyethylene resin composition is 20 kgf cm / cm to 50 kgf cm / cm polyethylene resin composition. A molded article manufactured from the polyethylene resin composition according to any one of claims 1 to 8.