KR20120093004A - Polylactic acid-polypropylene resin composition - Google Patents

Abstract

PURPOSE: A polylactic acid-polypropylene based resin composition is provided to have excellent parison stability at hollow molding by improving melt performance, and to be used as daily supplies, industrial material, and packing material. CONSTITUTION: A polylactic acid-polypropylene based resin composition comprises a polylactic acid resin, a polypropylene based resin, a glycidyl(meth)acrylate based copolymer and ethylene-(meth)acrylate copolymer-containing, or glycidyl(meth)acrylate-ethylene-octene copolymer containing compatibilizer, and an impact reinforcement. A content of the polylactic acid resin is 25-50 parts by weight based on 100.0 parts by weight of the resin composition. The polypropylene based resin is a polypropylene polymer, or a copolymer of polypropylene and aliphatic alpha-olefin or aromatic olefin.

Description

Polylactic acid-polypropylene resin composition

The present invention relates to a polylactic acid-polypropylene-based resin composition and a molded article produced from the resin composition.

Background Art Thermoplastic resins such as polyethylene, polypropylene, polystyrene, polyethylene terephthalate, and polyvinyl chloride are widely used in packaging materials, food containers, sundries, and household electronic products. Products based on the thermoplastic resin have been used for as little as one year or as long as ten years and then disposed of and eventually landfilled or incinerated.

Recently, the use of the thermoplastic resin has increased significantly, and global warming, depletion of petroleum resources, and waste problems have emerged all over the world, and interest in plastics using plants or natural materials that can replace existing petrochemical raw materials has increased rapidly. have. In particular, greenhouse gas reduction agreements, such as the Kyoto Protocol and Bali Roadmap, have accelerated the interest and development of biomass plastics using plastics made from plant or natural materials instead of plastics made from petrochemical raw materials.

Examples of biomass plastics include polyglycolic acid, polylactic acid, polycaprolactone, aliphatic polyester, and the like. Since polylactic acid is made from lactic acid obtained by fermentation of plant-derived starch such as corn or sweet potato, it is not prone to rely on limited petrochemical resources and is promising because it is superior in terms of cost and physical properties compared to other resins. . Polylactic acid is obtained by ring-opening polymerization of lactic acid as a raw material, whereby crystalline or amorphous polylactic acid is prepared according to the content of the optical isomer of lactic acid. The polylactic acid is used so much as to account for 20% of the total bioplastics at low cost and excellent physical properties compared to other biomass plastics.

Meanwhile, polypropylene and low density polyethylene, which are polyolefin resins, have been typically used as daily containers for daily life. Although the study of alloys with polylactic acid has been conducted in the general biomass total concept, the rigid molecular structure of polylactic acid has disadvantages such as low elongation and flexibility and low impact resistance. In addition, the compatibility between the polylactic acid and the polyolefin also has a disadvantage.

In order to improve the problem of the compatibility fall between such a fault of polylactic acid and a polyolefin, for example, Patent Literature 1 discloses a composition containing a polylactic acid, a polyolefin, and a functional group-containing hydrogenated diene copolymer. However, the composition has a problem that the impact resistance is insufficient. Patent Document 2 discloses a parallel use of various polypropylene resins such as polylactic acid and polypropylene homopolymer, polypropylene block copolymer, random copolymer, modified polypropylene, etc., but the resin composition prepared is a bottle (bottle) There is a problem that the impact resistance is poor for use in blow applications such as).

In addition, Patent Document 3 and Patent Document 4 disclose a method of adding an epoxy-modified polyethylene and an ethylene-octene copolymer to a polylactic acid and a polypropylene homopolymer resin composition. However, the resin composition prepared above is incompatible with polylactic acid and polypropylene for use in blowing applications.

Patent Document 1: Korean Patent Publication No. 10-2007-0059091 Patent Document 2: Japanese Patent Application Laid-Open No. 2008-260861 Patent Document 3: Japanese Patent Application Laid-Open No. 2010-144047 Patent Document 4: Japanese Patent Application Laid-Open No. 2010-144048

It is an object of the present invention to provide a resin composition which is excellent in parison stability during blow molding and which can be molded into household goods, industrial materials and packaging materials.

The present invention is a polylactic acid resin; Polypropylene resin; Compatibilizers containing glycidyl (meth) acrylate-based copolymers and ethylene- (meth) acrylate copolymers or containing glycidyl (meth) acrylate-ethylene-octene copolymers; And

The present invention relates to a polylactic acid-polypropylene-based resin composition containing an impact modifier.

Hereinafter, the polylactic acid-polypropylene resin composition according to the present invention will be described in detail.

In the polylactic acid-polypropylene-based resin composition according to the present invention, the weight average molecular weight of the polylactic acid resin may be 150,000 to 500,000. If the weight average molecular weight is less than 150,000, the physical properties and flow characteristics of the resin composition to be prepared are not sufficient, such as blow molding, etc., and if the weight average molecular weight exceeds 500,000, problems may arise in compatibility with the polypropylene resin, processability, and the like. .

In the present invention, the polylactic acid resin may be at least one selected from the group consisting of poly L-lactic acid, poly D-lactic acid and poly L, D lactic acid.

In the present invention, the polylactic acid resin is preferably used having a high optical purity, preferably in the present invention poly L-lactic acid having an optical purity of 85% or more, more preferably poly L-lactic acid having an optical purity of 95% or more It is good to use. If the optical purity is high, the heat resistance and crystallization rate of the resin composition may be increased.

The content of the polylactic acid resin in the present invention may be 25 to 50 parts by weight based on 100 parts by weight of the total resin composition. If the content is less than 25 parts by weight, the use effect of the plant-based resin may be less, and if it exceeds 50 parts by weight, there is a possibility that overall physical properties such as compatibility, elongation, impact resistance and heat resistance with polypropylene resin may occur. .

In the polylactic acid-polypropylene resin composition according to the present invention, the polypropylene resin is a polymer containing propylene as a main component.

In the present invention, a polypropylene polymer may be used as the polypropylene resin, or a copolymer of propylene and an aliphatic alpha (α) -olefin and / or an aromatic olefin may be used. Here, the aliphatic alpha (α) -olefin and the aromatic olefin may have 2 to 20 carbon atoms (excluding 3 carbon atoms), and preferably 2 to 8 carbon atoms (excluding 3 carbon atoms). have.

Specifically, as the polypropylene resin, a polypropylene polymer or a copolymer of propylene and at least one olefin selected from the group consisting of ethylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, and the like may be used. More specifically, at least one selected from the group consisting of polypropylene polymer, polypropylene copolymer, propylene-alpha-olefin copolymer, propylene-ethylene copolymer, propylene-butene copolymer and propylene-ethylene-butene copolymer Can be used. Here, the copolymer may be a random or block copolymer.

In the present invention, the polypropylene resin may have a melt flow index measured at 230 ° C. and a load of 2.16 kg? F in accordance with ASTM-D1238, in a range of 0.1 to 10 g / 10 min, preferably 0.1 to 0.8. g / 10 min. Outside the above limited range, the flow index of the polylactic acid-polypropylene resin composition may not be suitable for the flow viscosity of the parison for blow molding, which may cause problems in molding.

In addition, the content of the polypropylene resin in the present invention may be 30 to 70 parts by weight based on 100 parts by weight of the total resin composition. If the content is less than 30 parts by weight, the compatibility with polylactic acid is lowered, there is a fear that the heat resistance, appearance and impact resistance is lowered. If the content is more than 70 parts by weight, the content of polylactic acid is relatively lowered, the environmentally friendly material development There is a fear of failing to achieve the purpose.

In the polylactic acid-polypropylene-based resin composition according to the present invention, a compatibilizer is used to improve the melt properties of the polylactic acid resin and the polypropylene resin to promote parison stability and to improve dispersibility impact resistance.

In the present invention, the compatibilizer may contain a glycidyl (meth) acrylate copolymer and an ethylene- (meth) acrylate copolymer or may contain a glycidyl (meth) acrylate-ethylene-octene copolymer. .

In the present invention, the glycidyl (meth) acrylate copolymer means a copolymer containing glycidyl (meth) acrylate as a polymerized unit. Here, the copolymer may be a block or random copolymer.

The type of comonomer which may be included in the glycidyl (meth) acrylate copolymer is not particularly limited, and for example, olefin and (meth) acrylate may be used.

Specifically, the glycidyl (meth) acrylate copolymer, ethylene- glycidyl (meth) acrylate (etylene-glycidyl metacrylate) copolymer, glycidyl (meth) acrylate- ethylene- octene copolymer, Ethylene- (n-butyl acrylate) -glycidyl (meth) acrylate (ethylene- (n-butyl acrylate)-glycidyl metacrylate) copolymer, ethylene-methyl acrylate-glycidyl (meth) acrylate (ethylene- ( One or more selected from the group consisting of methyl carylate) glycidyl metacrylate copolymer and styrene glycidyl (meth) acrylate copolymer may be used.

In the present invention, the ethylene- (meth) acrylate copolymer includes ethylene and (meth) acrylate as polymerized units. The copolymer may be a random or block copolymer.

Specifically, the ethylene- (meth) acrylate copolymers include ethylene-methylacrylate copolymer, ethylene-ethylacrylate, ethylene-butyl acrylate, and the like. One or more selected from the group consisting of:

In the present invention, the content of glycidyl (meth) acrylate in the glycidyl (meth) acrylate-based copolymer is preferably 9% by weight or more. If the content of the glycidyl (meth) acrylate is less than 9% by weight, there is a fear that the compatibility between polylactic acid and polypropylene resin is lowered, the upper limit is not particularly limited, but 20% by considering the economical efficiency of the compatibilizer It may be less than or equal to%.

In the present invention, the content of (meth) acrylate in the ethylene- (meth) acrylate copolymer is preferably 30% by weight or more. If the content of the (meth) acrylate is less than 30% by weight, the compatibility between the polylactic acid and the polypropylene resin may decrease, and the upper limit thereof is not particularly limited.

In the present invention, glycidyl (meth) acrylate-ethylene-octene copolymer refers to a copolymer comprising glycidyl (meth) acrylate, ethylene and octene as polymerized units. In the present invention, the copolymer may be in the form of a random, block or graft copolymer, preferably in the form of a grafted glycidyl (meth) acrylate to the copolymer of ethylene and octene.

In the present invention, the content of glycidyl (meth) acrylate copolymer and ethylene- (meth) acrylate is 1 to 10 parts by weight of glycidyl (meth) acrylate copolymer and ethylene- based on 100 parts by weight of the total resin composition. 1-10 weight part of (meth) acrylate copolymers can be used. If the content of glycidyl (meth) acrylate copolymer and ethylene- (meth) acrylate is less than 1 part by weight, respectively, the compatibility and blow moldability may be deteriorated. If each of the content exceeds 10 parts by weight, mechanical properties This may fall.

In addition, the total content of the compatibilizer in the present invention may include 1 to 20 parts by weight, preferably 3 to 15 parts by weight based on 100 parts by weight of the total resin composition. When the content is less than 1 part by weight, the compatibility of polylactic acid and polypropylene may be lowered, and effects such as parison stability may be lowered. When the content is more than 20 parts by weight, it is more excellent than when used at 20 parts by weight or less. Since it does not show an effect, there exists a possibility that manufacturing cost may rise.

In the polylactic acid-polypropylene-based resin composition according to the present invention, the impact modifier may impart excellent impact strength and elongation to the resin composition to be produced.

In the present invention, the impact modifiers include olefinic impact modifiers, acrylic impact modifiers, methyl (meth) acrylate-butadiene-styrene (MBS) impact modifiers, styrene-ethylene-butadiene-styrene impact modifiers, silicone impact modifiers, and poly impact modifiers. One or more selected from the group consisting of ester elastomeric impact modifiers may be used, and olefinic impact modifiers may be preferably used in consideration of compatibility, impact resistance, and cost.

As the olefinic impact modifier in the present invention, one or more ethylene- (alpha-olefin) -based copolymers selected from the group consisting of ethylene-1-octene copolymers, ethylene-butene copolymers and ethylene-propylene copolymers may be used. . The ethylene- (alpha-olefin) based copolymer includes a metallocene catalyst and may have excellent elasticity, flexibility, and impact resistance.

In the present invention, the olefinic impact modifier may have a flow index of 0.1 to 5 g / 10 min, measured at 190 ° C. and a load of 2.16 kg · f. If the flow index is less than 0.1 g / 10min, the fluidity of the impact modifier is low, there is a fear of the problem of dispersion, if it exceeds 5 g / 10min, there is a fear that problems in securing the fluidity for blow molding.

The content of the impact modifier in the present invention may be used in 5 to 20 parts by weight based on 100 parts by weight of the total resin composition. The resin composition prepared in the above content range may have sufficient impact strength and elongation. If the content is less than 5 parts by weight, the impact resistance may be lowered. If the content exceeds 20 parts by weight, the impact resistance and elongation may be excellent. There exists a possibility that the physical property degradation, such as compatibility and heat resistance of a polylactic acid and a polypropylene resin, may arise.

The polylactic acid-polypropylene resin composition according to the present invention is a flame retardant, a lubricant, an antioxidant, a light stabilizer, a chain extender, a reaction catalyst, a release agent, a pigment, a dye, an antistatic agent, a conductivity providing agent, an EMI shielding agent, a magnetic imparting agent, It may further comprise one or more additives selected from the group consisting of crosslinking agents, antibacterial agents, processing aids, metal deactivators, depressants, fluorine-based anti-drip agents, inorganic fillers, glass fibers, friction wear and coupling agents. The additives may be used within a range that does not significantly affect the physical properties according to the present invention.

The method for producing the polylactic acid-polypropylene-based resin according to the present invention is not particularly limited and may be performed by a general method in the art.

In the present invention, the resin may be prepared by a method including mixing and extruding a polylactic acid resin, a polypropylene resin, a compatibilizer, and an impact modifier.

In the present invention, the polylactic acid resin, polypropylene resin, compatibilizer, and impact modifier may be used in the above-described types and contents.

In the present invention, the resin composition is first mixed in a super mixer or the like, followed by melt kneading using various compounding machines including a twin screw extruder, single screw extruder, roll mill, kneader, or banbury mixer, and then pelletizer. The pellets may be obtained and then dried in a dryer such as a dehumidifying dryer or a hot air dryer to prepare a resin.

The present invention also relates to a polylactic acid-polypropylene-based molded article produced by molding the aforementioned polylactic acid-polypropylene-based resin composition.

The molding may be performed by extruding or blow molding a polylactic acid-polypropylene-based resin.

In the present invention, the polylactic acid-polypropylene-based molded article may be a bottle, a sheet, or a film.

In particular, blow molding can be used to produce packaging containers, household goods containers or industrial parts made of single or multiple layers.

It is possible to provide a resin composition which is excellent in parison stability during blow molding due to the improvement of melt properties by increasing the compatibility, and which can be used as household goods, industrial materials and packaging materials.

Hereinafter, the present invention will be described in more detail with reference to the following examples and comparative examples, but the scope of the present invention is not limited by the following examples.

Example 1

30 parts by weight of polylactic acid resin (2002D, Nature works), 54 parts by weight of random polypropylene resin (R6200, LG Chemical), ethylene-glycidyl (meth) acrylate copolymer (EGMA, GMA content 12% by weight) 3 Parts by weight, ethylene-methyl acrylate copolymer (EMA, MA content 35% by weight) and 10 parts by weight of ethylene-1-octene copolymer (EOR, LG170, LG Chem) in a super mixer Extrusion process was carried out by melt kneading in a temperature range of 200 to 230 ℃ using an extruder. After final pelletizing and drying at 80 ° C. for at least 4 hours, injection molding was carried out and left for 1 day to obtain a specimen.

Example 2

Glycidyl (meth) acrylate-ethylene-octene copolymer (GMA-g-EOR, GMA content 9 to 10 wt%) in which glycidyl (meth) acrylate is grafted to a copolymer of ethylene and octene instead of EGMA A specimen was obtained in the same manner as in Example 1 except that 3 parts by weight of was used.

Example 3

A specimen was obtained in the same manner as in Example 1 except that 40 parts by weight of polylactic acid resin, 40 parts by weight of random polypropylene resin, 5 parts by weight of EGMA and 5 parts by weight of EMA were used.

Example 4

Without using EGMA and EMA, except 30 parts by weight of polylactic acid resin, 54 parts by weight of random polypropylene resin and 6 parts by weight of glycidyl (meth) acrylate-ethylene-octene copolymer (GMA-g-EOR) Then, a specimen was obtained in the same manner as in Example 1.

Example 5

A specimen was obtained in the same manner as in Example 1, except that 40 parts by weight of polylactic acid resin, 40 parts by weight of random polypropylene resin, and 10 parts by weight of GMA-g-EOR were used without using EGMA and EMA.

Comparative Example 1

A specimen was obtained in the same manner as in Example 1, except that 20 parts by weight of polylactic acid resin and 67 parts by weight of random polypropylene resin were used without using EMA.

Comparative Example 2

A specimen was obtained in the same manner as in Example 1, except that 40 parts by weight of polylactic acid resin and 50 parts by weight of random polypropylene resin were used without using EGMA and EMA.

Comparative Example 3

A specimen was obtained in the same manner as in Example 1, except that 40 parts by weight of polylactic acid resin, 40 parts by weight of random polypropylene resin, and 10 parts by weight of EMA were used without using EGMA.

Comparative Example 4

40 parts by weight of polylactic acid resin, 40 parts by weight of random polypropylene resin and 10 parts by weight of maleic anhydride-graft-polypropylene copolymer (MAH-g-PP, MAH content 0.8 to 1%) without using EGMA and EMA A specimen was obtained in the same manner as in Example 1 except that it was used.

Comparative Example 5

40 parts by weight of polylactic acid resin, 40 parts by weight of random polypropylene resin and 10 parts by weight of maleic anhydride-graft-ethylene octene copolymer (MAH-g-EOR, MAH content 0.5%) without using EGMA and EMA Except that the specimen was obtained in the same manner as in Example 1.

Comparative Example 6

Without using EGMA and EMA, except 40 parts by weight of polylactic acid resin, 40 parts by weight of random polypropylene resin and 10 parts by weight of acrylic acid-grafted-polypropylene copolymer (AA-g-PP, AA content 6%) Then, a specimen was obtained in the same manner as in Example 1.

Test Example

Using the specimens prepared by the above Examples and Comparative Examples, physical properties and parison stability were evaluated, and the results are shown in Tables 1 and 2 below.

(1) Property evaluation

* Tensile strength and elongation: measured by ASTM D638 method.

* Flexural strength and modulus: measured by ASTM D790 method.

Notched Izod impact strength: Notched Izod impact strength was measured at room temperature (23 ° C.) after notching in a 1/8 inch thick specimen according to ASTM D256.

(2) parison stability evaluation

* By using Extrusion-Blow Machine, it was processed at 200 ℃ and visually judged the change of thickness, sagging and appearance of parison coming out from the die with the naked eye. ◎ (Excellent), ○ ( Excellent), Δ (good) and X (poor).

division Example One 2 3 4 5 Furtherance PLA 30 30 40 30 40 random PP 54 54 40 54 40 EGMA 3 5 GMA-g-EOR 3 6 10 EMA 3 3 5 MAH-g-PP MAH-g-EOR AA-g-pp EOR 10 10 10 10 10 Properties Tensile strength (kgf / cm ² ) 270 280 270 266 258 Tensile Elongation (%) 480 450 280 530 340 Flexural modulus (kgf / cm ² ) 12300 13000 14300 12200 13000 Flexural Strength (kgf / cm ² ) 395 430 410 390 400 Izod impact strength (kgfcm / cm) 50 43 40 65 50 Parison stability ○ ○ ◎ ○ ◎

division Comparative example One 2 3 4 5 6 Furtherance PLA 20 40 40 40 40 40 random PP 67 50 40 40 40 40 EGMA 3 GMA-g-EOR EMA 10 MAH-g-PP 10 MAH-g-EOR 10 AA-g-pp 10 EOR 10 10 10 10 10 10 Properties Tensile strength (kgf / cm ² ) 285 280 260 275 250 270 Tensile Elongation (%) 500 13 100 20 50 17 Flexural modulus (kgf / cm ² ) 13300 13700 12500 13300 12000 13000 Flexural Strength (kgf / cm ² ) 450 420 330 400 390 380 Izod impact strength
(kgfcm / cm) 60 7 15 17 20 9 Parison stability △ X X X X X

The resins of Examples 1 to 3 using glycidyl (meth) acrylic copolymer and ethylene methyl acrylate and Examples 4 to 5 using glycidyl (meth) acrylate-ethylene octene copolymer have parison stability. It is excellent in that the parison thickness is constant and the sagging characteristic is low.

On the other hand, the resin composition of the comparative example did not secure sufficient parison stability at the time of blow. This is because it does not show a sufficient compatibility role as a compatibilizer at the interface between polylactic acid and polypropylene, resulting in poor melt tension and parison stability required for blow.

Claims (14)

Polylactic acid resins; Polypropylene resin; Compatibilizers containing glycidyl (meth) acrylate-based copolymers and ethylene- (meth) acrylate copolymers or containing glycidyl (meth) acrylate-ethylene-octene copolymers; And
Polylactic acid-polypropylene-based resin composition comprising an impact modifier.
The method of claim 1,
The content of the polylactic acid resin is 25 to 50 parts by weight based on 100 parts by weight of the total resin composition polylactic acid-polypropylene resin composition.
The method of claim 1,
The polypropylene resin is a polylactic acid-polypropylene-based resin composition which is a polypropylene polymer or a copolymer of polypropylene and aliphatic alpha (α) -olefin or aromatic olefin.
The method of claim 1,
The polypropylene resin is a polylactic acid-polypropylene resin composition having a flow index of 0.1 to 10 g / 10 min measured at a load of 230 ° C. and a load of 2.16 kg · f.
The method of claim 1,
The polypropylene resin is a polylactic acid-polypropylene resin composition is 30 to 70 parts by weight based on 100 parts by weight of the total resin composition.
The method of claim 1,
The content of glycidyl (meth) acrylate in the glycidyl (meth) acrylate copolymer is at least 9% by weight, and the content of (meth) acrylate in the ethylene- (meth) acrylate copolymer is at least 30% by weight. Polylactic acid-polypropylene resin composition.
The method of claim 1,
Polylactic acid-polypropylene having a content of glycidyl (meth) acrylate copolymer in an amount of 1 to 10 parts by weight and an content of an ethylene- (meth) acrylate copolymer in an amount of 1 to 10 parts by weight based on 100 parts by weight of the total resin composition. System resin composition.
The method of claim 1,
The impact modifier is an olefinic impact modifier, polylactic acid-polypropylene resin composition.
The method of claim 8,
The olefinic impact modifier is at least one selected from the group consisting of ethylene-1-octene copolymer, ethylene-butene copolymer and ethylene-propylene copolymer.
The method of claim 8,
The olefinic impact modifier is a polylactic acid-polypropylene-based resin composition having a flow index of 0.1 to 5 g / 10 min measured at 190 ° C and a load of 2.16 kgf.
The method of claim 1,
The content of the impact modifier is 5 to 20 parts by weight based on 100 parts by weight of the total resin composition polylactic acid-polypropylene resin composition.
The method of claim 1,
Flame Retardants, Lubricants, Antioxidants, Light Stabilizers, Chain Extenders, Reaction Catalysts, Release Agents, Pigments, Dyes, Antistatic Agents, Conductive Agents, EMI Shielding Agents, Magnetic Enhancers, Crosslinking Agents, Antibacterial Agents, Processing Aids, Metal Deactivators, Depressants A polylactic acid-polypropylene resin composition further comprising at least one additive selected from the group consisting of a fluorine-based anti-drip agent, an inorganic filler, a glass fiber, an anti-friction wear agent, and a coupling agent.
A polylactic acid-polypropylene-based molded article prepared by blow molding the polylactic acid-polypropylene-based resin composition according to claim 1.
The method of claim 13,
The molded article is a polylactic acid-polypropylene-based molded article which is a bottle, a sheet or a film.