KR102437733B1 - Eco-friendly resin composition and manufacturing method thereof - Google Patents

Abstract

The present invention provides an eco-friendly resin composition which comprises: a core including a polypropylene resin modified with a polypropylene resin and dicarboxylic acid or an acid anhydride thereof; and a core-shell composite located on the core and including a shell containing an aliphatic polyester biodegradable resin, wherein the weight ratio of the polypropylene resin in the core and the biodegradable resin in the shell is 9 : 1 to 6 : 4.

Description

Eco-friendly resin composition and its manufacturing method {ECO-FRIENDLY RESIN COMPOSITION AND MANUFACTURING METHOD THEREOF}

The present invention relates to an eco-friendly resin composition and a method for manufacturing the same, and more particularly, to an eco-friendly resin composition having improved mechanical properties and fluidity as well as biodegradability by introducing a core-shell structure composite including a biodegradable resin. .

Plastics can be freed from the limitations and restrictions of natural materials due to their excellent properties and cheap and light properties, and the use of plastics is steadily increasing due to these properties. However, due to environmental pollution caused by plastic waste, for example, detection of dioxins or leakage of environmental hormones, social demand for eco-friendly plastics as well as legal regulations on the use of non-degradable plastics are increasingly being strengthened.

Accordingly, the need for the use of biodegradable plastic in which the plastic itself can be decomposed has been greatly increased. However, biodegradable polymers have reduced performance in terms of mechanical properties and thermal stability to be used alone, so research is being conducted to improve physical properties through blends with various types of polymers.

Conventionally, studies have been attempted to control the rate of disintegration of plastics after use by adding a small amount of polylactic acid (PLA) or polycaprolactone (PCL), represented by biodegradable resins, to an olefin-based resin. However, since the biodegradable resin and the olefin-based resin do not have a functional group that enables chemical bonding, and are only physically bonded, a phenomenon occurs in which mechanical properties are deteriorated when blended. In addition, the two resins do not have good mutual compatibility, so the polymers are agglomerated at the interface of the mixture, making it difficult to mix and use, and their use is limited due to poor physical properties when manufactured as a product.

Accordingly, in order to impart biodegradability, there is a need to develop an eco-friendly resin composition with improved mechanical properties and processability without the problem of deterioration in physical properties caused by compatibility problems when using biodegradable resins.

It is an object of the present invention to provide a hydrophilic resin composition having improved mechanical properties and biodegradability by increasing the compatibility of a biodegradable resin and a polypropylene resin.

In addition, another object of the present invention is to provide an eco-friendly resin composition capable of manufacturing a molded article of uniform quality by suppressing the non-uniformity in the supply of raw materials during the extrusion molding process by providing an eco-friendly resin composition with improved fluidity.

Another object of the present invention is to provide a method for preparing the above-described hydrophilic resin composition.

The present invention provides a core comprising a polypropylene resin and a polypropylene resin modified with a dicarboxylic acid or an acid anhydride thereof; and

It is located on the core and includes a core-shell composite including a shell including an aliphatic polyester-based biodegradable resin,

The weight ratio of the polypropylene resin in the core and the biodegradable resin in the shell is 9:1 to 6:4, providing an eco-friendly resin composition.

According to one embodiment, the modified polypropylene resin may have a graft rate of 0.1 to 10% by weight, and a weight average molecular weight of 1,000 to 100,000 g/mol.

According to one aspect, the modified polypropylene resin is at least one selected from the group consisting of itaconic acid grafted polypropylene (IA-g-MAH) and maleic anhydride grafted polypropylene (PP-g-MAH). may include

According to one embodiment, based on 100 parts by weight of the polypropylene resin in the core, 1 to 20 parts by weight of the modified polypropylene resin may be included.

The present invention also

a) preparing a core comprising a polypropylene resin and a polypropylene resin modified with a dicarboxylic acid or an acid anhydride thereof; and

b) forming a shell comprising an aliphatic polyester-based biodegradable resin on the core,

The weight ratio of the polypropylene resin in the core and the biodegradable resin in the shell is 9:1 to 6:4, providing a method for producing an eco-friendly resin composition.

The eco-friendly resin composition according to the present invention can improve biodegradability and mechanical properties by including a core-shell composite including a biodegradable resin.

In addition, there is an advantage in that it is possible to manufacture molded products of uniform quality by improving the fluidity of the eco-friendly resin composition during the extrusion molding process.

Advantages and features of the present invention, and methods of achieving them, will become apparent with reference to the embodiments described below in detail. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention belongs It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims. “And/or” includes each and every combination of one or more of the recited items.

Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used with the meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In the entire specification, when a part "includes" a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise stated. The singular also includes the plural unless the phrase specifically states otherwise.

The present invention provides a core comprising a polypropylene resin and a polypropylene resin modified with a dicarboxylic acid or an acid anhydride thereof; and a core-shell composite disposed on the core and including a shell including an aliphatic polyester-based biodegradable resin, wherein a weight ratio of the polypropylene resin in the core and the biodegradable resin in the shell is 9:1 to 6 : Provides an eco-friendly resin composition for 4 people.

The polypropylene resin may include at least one selected from a propylene homopolymer, a propylene random copolymer, and a propylene block copolymer as a base of the eco-friendly resin composition according to the present invention. In addition, the polypropylene resin is preferably a melt index (melting index, MI) 0.5 ~ 30 g / 10 min (ASTM D 1238, 230 ℃). Accordingly, it is possible to secure impact rigidity without lowering the moldability and productivity of the resin composition according to the present invention.

The modified polypropylene resin may be a polypropylene resin grafted with dicarboxylic acid or an acid anhydride thereof. The dicarboxylic acid is maleic acid, phthalic acid, itaconic acid, citraconic acid, alkenylsuccinic acid, cis-1,2,3,6-tetrahydrophthalic acid, 4-methyl-1,2,3,6-tetrahydrophthalic acid or It may include a mixture of two or more thereof, and the acid anhydride of the dicarboxylic acid may be the dicarboxylic acid anhydride of the above-described examples.

According to an embodiment of the present invention, the modified polypropylene resin is selected from the group consisting of itaconic acid grafted polypropylene (PP-g-IA) and maleic anhydride grafted polypropylene (PP-g-MAH). It may include one or more, preferably itaconic acid grafted polypropylene (IA-g-MAH).

As the core includes the above-mentioned modified polypropylene resin, it is possible to significantly increase mechanical properties by inducing interfacial adhesion between the polypropylene resin included in the core and the biodegradable resin included in the shell.

The modified polypropylene resin may have a graft rate of 0.1 to 10% by weight, preferably 0.1 to 5% by weight, more preferably 0.5 to 3% by weight, and a weight average molecular weight of 1,000 to 500,000 g/mol, preferably may be 10,000 to 500,000 g/mol. By satisfying the above conditions, it is possible to increase the compatibility of the polypropylene resin included in the core and the biodegradable resin included in the shell, thereby improving the uniformity and phase stability of the resin composition.

According to one embodiment of the present invention, it is preferable that the polypropylene resin in the core and the polypropylene resin of the modified polypropylene resin are the same, and more preferably, the polypropylene resin has an ethylene content of 15 mol% or less propylene-ethylene copolymer It may contain synthesis.

In terms of more efficiently expressing the above-mentioned effects, with respect to 100 parts by weight of the polypropylene resin in the core, 1 to 20 parts by weight of the modified polypropylene resin, preferably 2 to 18 parts by weight, more preferably It may contain 4 to 16 parts by weight.

The biodegradable resin is completely converted into water, carbon dioxide, nitrogen and biomass by the action of microorganisms such as mold and bacteria and environmental factors such as light, heat, and humidity, and is preferably an aliphatic polyester-based resin. It may contain a biodegradable resin.

Specifically, the aliphatic polyester-based biodegradable resin may include at least one selected from the group consisting of polylactic acid (PLA) and polybutylene succinate (PBS), preferably poly lactic acid.

It is effective that the polylactic acid has a number average molecular weight of 10,000 to 100,000 and at least one selected from the group consisting of poly-L-lactic acid, poly-D-lactic acid, and poly-L,D-lactic acid.

The eco-friendly resin composition according to the present invention contains the above-described polylactic acid in the shell of the core-shell composite, so that the properties such as chemical resistance and moisture barrier properties of the polypropylene resin in the core and the excellent tensile strength of the polylactic acid resin in the shell and It is possible to efficiently express the elongation property at the same time. Accordingly, it is possible to simply increase the bonding force between the interfaces of the different types of resins compared to the resin composition in which the polypropylene resin and polylactic acid resin are mixed in the presence of a compatibilizer, thereby improving physical properties such as mechanical strength, moisture resistance, and thermal stability. can

The weight ratio of the polypropylene resin in the core and the biodegradable resin in the shell is 9:1 to 6:4, preferably 9:1 to 7:3, more preferably 8.5:1.5 to 7.5:2.5. If it is out of the above range, there may be a problem that the biodegradation effect is insignificant or the above-described physical properties are deteriorated.

The shell may further include wax. As used herein, the "wax" refers to a monohydric or dihydric alcohol fatty acid ester that is not soluble in water. The wax may include at least one selected from the group consisting of natural wax, vegetable wax, and synthetic wax, and preferably, synthetic wax.

The synthetic wax may include at least one selected from the group consisting of polyalkylene wax and polyalkylene glycol wax, and preferably has a glass transition temperature (Tg) similar to the drying temperature during the core-shell composite manufacturing process. It can be characterized as having. Specifically, the drying process is a step of drying the solution containing the prepared core-shell composite to obtain a core-shell composite. Since it can be performed at 60 to 100° C., the glass transition degree (Tg) is 60 to It is preferred to include a polyethylene wax of 100°C, preferably 70 to 90°C. The drying process will be described in detail in the manufacturing method of the eco-friendly resin composition to be described later.

According to one embodiment of the present invention, 1 to 10 parts by weight of the wax, preferably 1 to 8 parts by weight, more preferably 1 to 5 parts by weight based on 100 parts by weight of the polypropylene resin in the core may be included. .

The average particle size of the wax may be 30 to 280 nm, preferably 30 to 250 nm, more preferably 50 to 200 nm, wherein the particle size may mean D50. When the above-described conditions are satisfied, the wax particles enter the grooves on the surface of the core particles or cover the groove surfaces, thereby reducing the surface roughness of the core particles. On the other hand, when out of the above range, the contact surface between the wax particle and the core particle may be relatively reduced to indicate low particle fluidity.

As the core-shell composite according to an embodiment of the present invention includes the above-mentioned wax in the shell, in the drying process, the wax undergoes a softening process and collision between particles or between particles and the device surface (dryer surface) This can lead to particle deformation. Accordingly, it is possible to reduce the surface roughness of the core particles, and furthermore, it is possible to significantly increase the fluidity by smoothing the surface of the prepared core-shell composite.

The core-shell composite may be particles having an average particle size of 10 to 1000 nm, or 50 to 800 nm, or 50 to 500 nm. When the above range is satisfied, it is effective in terms of dispersion stability of the composition, and aggregation phenomenon can be prevented.

As the eco-friendly resin composition according to an embodiment of the present invention includes the above-described core-shell composite, it is possible to increase mechanical properties and fluidity while exhibiting crystallinity and crystallinity for maintaining moisture and gas barrier properties.

The eco-friendly resin composition according to an embodiment of the present invention may further include a nucleating agent. The nucleating agent may include at least one selected from the group consisting of mica, talc, silica, calcium carbonate, clay, and cellulose fibers (including wood powder). . In terms of improving mechanical properties as a reinforcing agent while crystallization of the resin composition can occur easily, the nucleating agent may preferably include talc or calcium carbonate or mica, and most preferably include mica. .

Based on 100 parts by weight of the resin composition, 10 to 20 parts by weight of the nucleating agent, preferably 12 to 18 parts by weight, may be included. In the above range, it is possible to secure mechanical properties such as impact resistance of the manufactured molded article by maximizing the nucleation effect to increase the crystallization rate while suppressing the phenomenon that raw material input is not smooth during extrusion.

The eco-friendly resin composition according to an embodiment of the present invention can increase thermal stability by further including a thermal stabilizer. The heat stabilizer may preferably include a phosphite heat stabilizer, specifically composed of diphenyl isooctyl phosphite and distearyl pentaeryl diphosphite. It may include one or more selected from the group.

With respect to 100 parts by weight of the resin composition, 0.01 to 2 parts by weight, preferably 0.02 to 1 parts by weight of the thermal stabilizer, thereby maximizing the synergistic effect of thermal stability, and at the same time generating gas and odor due to excessive addition of the thermal stabilizer can be suppressed.

The eco-friendly resin composition according to an embodiment of the present invention further comprises a flame retardant, a lubricant, an antioxidant, a light stabilizer, a mold release agent, a pigment, an antistatic agent, an antibacterial agent, a processing aid, a metal deactivator, a flame retardant, a fluorine-based anti-drip agent, an inorganic filler, At least one additive selected from the group consisting of glass fibers, anti-friction agents, anti-wear agents, and coupling agents may be further included. The additive is not particularly limited as long as it is a material commonly used in the art.

In the case of extrusion molding using the eco-friendly resin composition according to an embodiment of the present invention, excellent biodegradability can be imparted and properties such as mechanical strength can be improved. In addition, it is possible to manufacture a molded article of uniform quality by improving the fluidity of the resin composition. In particular, it is possible to manufacture a film of uniform thickness by suppressing the non-uniformity in the supply of raw materials in the manufacturing process of the film for food packaging, and maximize properties such as gas and moisture barrier properties.

The present invention also comprises the steps of a) preparing a core comprising a polypropylene resin and a polypropylene resin modified with a dicarboxylic acid or an acid anhydride thereof; and b) forming a shell including an aliphatic polyester-based biodegradable resin on the core, wherein a weight ratio of the polypropylene resin in the core and the biodegradable resin in the shell is 9:1 to 6:4, A method for manufacturing an eco-friendly resin composition is provided.

Step a) is a step of preparing a core, and the core composition including the polypropylene resin and the modified polypropylene resin is prepared at 100 to 200° C., preferably 120 to 200° C., and a shear rate of 500 to 2500 1/s. , Preferably it can be carried out by mixing for 5 minutes to 60 minutes under the conditions of 1000 to 2500 1 / s. At this time, based on 100 parts by weight of the polypropylene resin in the core composition, 1 to 20 parts by weight of the modified polypropylene resin, preferably 2 to 18 parts by weight, more preferably 4 to 16 parts by weight may be included.

Step b) is a step of forming a shell on the core prepared in step a), and may be performed through polymerization, preferably free-radical polymerization using an initiator. Specifically, the core-shell composite may be prepared by adding an aliphatic ester-based monomer dropwise to a solution containing the core composition to perform a polymerization reaction. The polymerization reaction may be carried out at 50 to 120 °C, preferably at 60 to 100 °C for 0.5 to 2 hours. In this case, the aliphatic ester-based monomer preferably includes at least one selected from the group consisting of L-lactide and D-lactide.

Meanwhile, when performing the polymerization reaction, the initiator is azobisisobutyronitrile, 2,2-azobis-2,4-dimethylvaleronitrile, 2,2-azobismethylbutyronitrile, and 1,1 -azo initiators such as azobiscyclohexanecarbonitrile; peroxide-based initiators such as benzoyl peroxide, cumene hydroperoxide, t-butyl peroxide, t-butyl perbenzoate and methyl ethyl ketone peroxide; persulfate initiators such as ammonium persulfate, t-butyl hydrogen peroxide potassium persulfate, ammonium persulfate and potassium persulfate; persulfates; and peroxides such as hydrogen peroxide and peracetic acid, which may be used alone or in combination of two or more.

In terms of enabling efficient polymerization and minimizing the content of unreacted monomers in the polymerization process, the content of the initiator may be included in an amount of 1 to 15 parts by weight, or 2 to 10 parts by weight, based on 100 parts by weight of the total monomer mixture.

The solvent used in the polymerization reaction may include alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, methoxypropanol and diacetone alcohol; alcohol ethers such as methyl carbitol, ethyl carbitol and butyl carbitol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; esters such as methyl acetate, ethyl acetate and butyl acetate; aromatic hydrocarbons such as benzene, toluene and xylene; and amide-based solvents such as formamide and dimethylformamide, it is preferable to use an alcohol-based solvent in view of long-term durability.

In terms of ensuring excellent biodegradation effect and mechanical and thermal stability, the weight ratio of the polypropylene resin in the core and the biodegradable resin in the shell is 9:1 to 6:4, preferably 9:1 to 7:3, More preferably, it may be 8.5:1.5 to 7.5:2.5.

In the shell forming process of step b), wax may be further included. At this time, the wax used is the same as described above, and by forming a shell further including the wax on the core prepared in step a), the surface of the core-shell composite prepared by smoothing the surface of the prepared core-shell composite can be significantly increased. .

After step b), a drying step may be further performed after a vacuum filtering process. At this time, the filter is not particularly limited as long as it has a hole size of several micrometers to several tens of micrometers used in general.

The drying refers to drying the solution containing the core-shell composite prepared in step b), in which an inert gas such as nitrogen or argon is present at a temperature higher than the glass transition temperature (Tg) of the wax used in step b). It can be carried out under Specifically, drying may be performed at a drying temperature of 60 to 100° C., preferably 70 to 100° C., for 2 to 15 hours, preferably 4 to 14 hours. As the drying process is performed under the above-described conditions, the wax contained in the shell of the core-shell composite is softened, and the surface roughness of the core-shell composite particles is remarkably reduced, thereby increasing fluidity.

Hereinafter, the present invention will be described in detail by way of Examples, but these are for describing the present invention in more detail, and the scope of the present invention is not limited by the Examples below.

Example

(Example 1)

The core composition described in Table 1 below was mixed at 170° C. for 15 minutes to obtain a core material. Next, the core material was added to a four-necked flask equipped with a nitrogen inlet, a thermometer, a stirrer and a dropping funnel, and then the temperature of the reaction part was raised to 80° C. in the presence of propanol, a solvent for polymerization. Next, the shell composition shown in Table 1 was added dropwise at 80° C. over 1 hour to carry out a polymerization reaction in a nitrogen atmosphere, and then cooled to room temperature to prepare a solution containing a core-shell composite. Then, after vacuum filter, the core-shell composite was obtained through a drying process at 100° C. for 8 hours.

Then, a resin powder composition comprising 84 wt% of the prepared core-shell composite, 0.5 wt% of the heat stabilizer distearyl pentaeryl-diphosphite, and 15.5 wt% of the nucleating agent mica was prepared.

Furtherance Content (parts by weight) core composition Propylene/Ethylene Copolymer
(Ethylene content 2 mol%) 100 PP-g-IA 10 shell composition L-lactide 25 2,2-Azobis 2-Methylbutyronitrile 8

(Examples 2-4)

A resin powder composition was prepared in the same manner as in Example 1, except that a core-shell composite was prepared under the composition conditions shown in Table 2 below.

(Example 5)

A resin powder was prepared without using a heat stabilizer and a nucleating agent so that the core-shell composite prepared in Example 1 was included in an amount of 100% by weight.

(Comparative Example 1)

A resin powder composition was prepared in the same manner as in Example 1, except that a blend obtained by melt-mixing 100 parts by weight of polypropylene, 10 parts by weight of PP-g-IA and 25 parts by weight of polylactic acid was used instead of the core-shell composite in Example 1 prepared.

(Comparative Example 2)

A resin powder composition was prepared in the same manner as in Example 1, except that PP-g-IA was not added when preparing the core material.

(Comparative Example 3)

A resin powder composition was prepared in the same manner as in Example 1, except that 100 parts by weight of L-lactide was used instead of 25 parts by weight when forming the shell.

Furtherance Content (parts by weight) Example 2 Example 3 Example 4 core composition Propylene/ethylene copolymer (ethylene content 2 mol%) 100 100 100 PP-g-IA 10 - 10 PP-g-MAH - 10 - shell composition L-lactide 25 25 - D-lactide - - 25 2,2-Azobis 2-Methylbutyronitrile 8 8 8 Polyethylene wax (Tg: 80℃) 2 2 2

Experimental Example 1: Evaluation of physical properties

* Measurement of tensile strength and elongation

Specimens having a width of 12.7 mm X a length of 12.7 mm X a height of 3.2 mm were prepared by injection molding each of the resin powder compositions prepared according to Examples 1 to 5 and Comparative Examples 1 to 3, respectively. Tensile strength and elongation of the prepared specimen were measured using a universal testing machine (UST) at room temperature according to ASTM D 638 standard, and the results are shown in Table 3 below. At this time, the cross-head speed of the universal testing machine was set to 5 mm/min, and the length of the gauge was set to 50 mm.

* Measurement of impact strength

Specimens having a width of 63.5 mm X length 12.7 mm X height 6.4 mm were prepared by injection molding the resin powder composition prepared according to Examples 1 to 5 and Comparative Examples 1 to 3, respectively. The prepared specimens were measured for impact strength in the Izod method at room temperature according to ASTM D 256 standard, and the results are shown in Table 3 below.

Experimental Example 2: Measurement of (angle of repose)

For the resin powder compositions prepared according to Examples 1 to 5 and Comparative Examples 1 to 3, the angle of repose was measured using a Powder tester (HOSOKAWA), and the results are shown in Table 3 below.

The tensile strength
(MPa) Elongation (%) impact strength
(kgf cm/cm) angle of repose
() Example 1 36 90 10.3 30 Example 2 38 97 11.6 26 Example 3 37 95 11.2 28 Example 4 36 96 11.4 27 Example 5 34 92 10.6 32 Comparative Example 1 26 43 3.8 42 Comparative Example 2 24 15 3.4 34 Comparative Example 3 30 75 4.0 38

As can be seen in Table 3, the eco-friendly resin composition according to the present invention exhibited excellent mechanical properties and an angle of repose of 32 or less by including a core-shell composite having a specific composition. The angle of repose is the maximum angle of inclination at which unconsolidated sediment can be deposited without flowing down when it is deposited on the slope. That is, it is a large angle between the natural surface of the granular material and the horizontal plate in a static equilibrium state, and the smaller the angle of repose, the better the fluidity of the granular material. Therefore, it can be confirmed that the fluidity of the eco-friendly resin powder composition according to the present invention is very good, and accordingly, smooth supply and extrusion of raw materials are made in the thermal processing process such as extrusion molding, so that the molded article is of uniform quality, more specifically, of uniform thickness. manufacturing becomes possible.

Claims (5)

a core comprising a polypropylene resin and a polypropylene resin modified with a dicarboxylic acid or an acid anhydride thereof; and
It is located on the core and includes a core-shell composite including a shell including an aliphatic polyester-based biodegradable resin,
The weight ratio of the polypropylene resin in the core and the biodegradable resin in the shell is 9:1 to 6:4, an eco-friendly resin composition. According to claim 1,
The modified polypropylene resin has a graft rate of 0.1 to 10% by weight, and a weight average molecular weight of 1,000 to 500,000 g/mol, an eco-friendly resin composition. 3. The method of claim 2,
The modified polypropylene resin is an eco-friendly resin comprising at least one selected from the group consisting of itaconic acid grafted polypropylene (PP-g-IA) and maleic anhydride grafted polypropylene (PP-g-MAH) composition. According to claim 1,
With respect to 100 parts by weight of the polypropylene resin in the core, the eco-friendly resin composition comprising 1 to 20 parts by weight of the modified polypropylene resin. a) preparing a core comprising a polypropylene resin and a polypropylene resin modified with a dicarboxylic acid or an acid anhydride thereof; and
b) forming a shell comprising an aliphatic polyester-based biodegradable resin on the core,
The weight ratio of the polypropylene resin in the core and the biodegradable resin in the shell is 9:1 to 6:4, a method for producing an eco-friendly resin composition.