KR101567196B1 - Composites of polypropylene and polylactic acid having high impact strength and heat resistance - Google Patents

Abstract

The present invention relates to a polypropylene-poly lactic acid composite material composition excellent in rigidity and heat resistance, and more particularly, to a resin composition comprising a polypropylene resin and an L- or D-polylactic acid resin in a predetermined ratio, Since reinforcing agent, glass fiber, nucleating agent and compatibilizer are included in a certain content ratio, the polypropylene-polylactic acid composite which can replace general-purpose polymer material greatly strengthens the properties such as heat resistance, impact resistance, tensile strength and bending strength of polylactic acid ≪ / RTI >

Description

TECHNICAL FIELD The present invention relates to a polypropylene-polylactic acid having high rigidity and heat resistance,

The present invention relates to a resin composition in which a polypropylene resin and an L- or D-polylactic acid resin are contained in a predetermined ratio, and a specific impact modifier, glass fiber, nucleating agent and compatibilizing agent are contained as additives in a predetermined ratio, , Impact resistance, tensile strength and flexural strength of the polypropylene-polylactic acid composite material composition.

Biomass Polymers are materials that are produced by using chemical or biological methods from renewable plant resources such as corn, soybeans, sugarcane and timber. They are used to reduce carbon dioxide and prevent environmental pollution by waste, compared with biodegradable polymer materials. .

Polylactic acid or polylactide (hereinafter referred to as PLA), which represents biomass polymers, is a linear aliphatic polyester and poly-L-lactic acid (PLLA) as an optical isomer. And poly-D-lactic acid (hereinafter referred to as " PDLA "). Generally, polylactic acid (PLA) is obtained by starch fermentation obtained from corn and potato, or obtained by polymerizing a sugar monomer obtained by saccharifying and fermenting a plant-based cellulose. Although such PLA is known as an environmentally friendly thermoplastic polymer material, it is inferior in respect of physical properties to general-purpose polymer materials and has a limited application field in industry. Particularly, it has poor characteristics compared to existing petroleum based materials in terms of heat resistance and impact resistance.

In order to improve the heat resistance of such a polylactic acid material, a method of blending a PLLA resin and a PDLA resin to form a stereo complex has been proposed. However, the proper composition ratio of PLLA resin and PDLA resin for improvement of heat resistance is not mentioned, and physical properties such as impact resistance are not improved, and there is a problem in application to automotive materials.

In order to improve the impact resistance, a polylactic acid resin (JP-A No. 2009-155413) comprising a poly (meth) acrylate resin, a polylactic acid resin with a poly (ethylene-glycidyl methacrylate) [U.S. Patent No. 7,268,190] and the like are disclosed. However, the above patent does not form a stereocomplex for improving heat resistance, and there is no mention of a composition ratio for controlling the impact strength and the tensile strength.

Also, some patents disclose a composite material in which a polypropylene resin is blended with a poly (lactic acid) resin. [Patent Document 1] Korean Unexamined Patent Publication No. 2011-0048125, No. 2012-0117130, No. 2012-0128732 In this patent, a poly (ethylene-n-butyl acrylate-glycidyl methacrylate) However, in order to be applied to automobile materials, reinforcement of heat resistance and impact resistance is required.

Therefore, the development of a new biocomposite material that satisfies the biomaterial content certification range required by the BioMark system while having durability and heat resistance suitable for automobile parts and industrial parts requiring high heat resistance and high impact resistance properties Is required.

Accordingly, the present inventors have made efforts to improve the disadvantages of low heat resistance and impact strength of poly (lactic acid) material derived from biomass. As a result, in the case of blending a polypropylene resin and a poly (lactic acid) in a certain composition ratio range and adding a specific impact modifier, glass fiber, nucleating agent and compatibilizing agent within a specific content ratio, crystallization degree of a resin material made of a polypropylene resin and a poly And the impact strength and heat resistance are remarkably improved, thereby completing the present invention.

Accordingly, it is an object of the present invention to provide a polypropylene-poly (lactic acid) composite material composition which simultaneously satisfies physical properties such as heat resistance, impact resistance, tensile strength and bending strength, and a method for producing the same.

In order to solve the above problems, the present invention provides a resin composition comprising 100 parts by weight of a resin component comprising 65 to 75% by weight of a polypropylene resin and 25 to 35% by weight of an L- or D- Acrylate-glycidyl methacrylate), 15 to 20 parts by weight of glass fiber, 0.5 to 3 parts by weight of an aromatic sulfonic acid and 1 to 10 parts by weight of a maleic anhydride grafted polypropylene resin as additives Which is excellent in rigidity and heat resistance.

Also, the present invention provides a method for producing a resin composition, which comprises melting and kneading a resin component having a ratio of 65 to 75% by weight of a polypropylene resin and 25 to 35% by weight of an L- or D-poly lactic acid resin at 190 to 210 ° C .; 3 to 10 parts by weight of poly (ethylene-n-butyl acrylate-glycidyl methacrylate), 15 to 20 parts by weight of glass fibers, 0.5 to 3 parts by weight of an aromatic sulfonic acid, 1 to 10 parts by weight of a grafted polypropylene resin to prepare a composite material composition; A step of preparing a molded article by injection molding the composite material composition; Wherein the polypropylene-polylactic acid composite material is a polypropylene-polylactic acid composite material.

The polypropylene-polybutylene composite material composition of the present invention is excellent in physical properties such as heat resistance, impact resistance, tensile strength and flexural strength, and thus can be used as various industrial materials. Particularly, It is suitable as material of. That is, it is suitable as an eco-friendly biomaterial that can replace general-purpose polymer resin (for example, ABS resin) used as a conventional automotive parts material.

As the resin component constituting the polypropylene-polyunsaturated fatty acid composite composition of the present invention, the polypropylene resin can satisfy all of the physical properties required for a composite material even if a new product or a regenerated product is used. If recycled polypropylene resin is used, it has a desirable effect in terms of resource recycling and cost reduction.

The polypropylene / polyunsaturated fatty acid composite material composition of the present invention contains 25% by weight or more of the biomass-derived polyunsaturated fatty acid resin, thereby satisfying the biomaterial content authentication range required by the biomark system conducted at home and abroad.

The components constituting the polypropylene-poly lactic acid composite material composition according to the present invention will be described in more detail as follows.

The composite material composition of the present invention comprises a polypropylene resin and a polylactic acid resin as a resin component.

The polypropylene resin may be a new product or may be a recycled product. The recycled polypropylene resin in the present invention refers to a recycled material obtained by recovering a molded article of a polypropylene material which is discarded in an industrial field or a home. In the adoption of the recycled polypropylene resin, There is no restriction. The recycled polypropylene resin recovered after scrapping after application as a vehicle component material can be more preferably used. The polypropylene resin used in the present invention may be a polypropylene homopolymer, a polypropylene block copolymer or a mixture thereof. The polypropylene resin may have a melt index (MI) of 10 to 40 g / 10 min (230 ° C, 2.16 kg load) Can be used. If the melt index of the polypropylene resin is less than 10 g / 10 min, there is a problem of overhead of processing due to an increase in melt viscosity. If the melt index exceeds 40 g / 10 min, there is a problem in melt-blending extrusion processing.

The polylactic acid may be an L-polylactic acid resin or D-polylactic acid resin having optical activity, and these are enantiomers. The L-poly lactic acid resin may be represented by the following formula (1), and D-poly lactic acid has an enantiomeric structure thereof.

The L- or D-poly lactic acid resin is a polymer synthesized from starch or biomass, and has a melt index (MI) of 5 to 40 g / 10 min (190 캜, 2.16 kg load). If the melt index of the L- or D-poly lactic acid resin is less than 5 g / 10 min, there may be a problem in overhead of processing due to an increase in melt viscosity. If the melt index exceeds 40 g / 10 min, There is a problem in extrusion processing.

The composite material composition of the present invention comprises 65 to 75% by weight of polypropylene and 25 to 35% by weight of polylactic acid as a resin component. If the content of polypropylene in the resin component is less than 65% by weight, the mechanical properties may deteriorate. When the amount of polypropylene is more than 75% by weight, the content of polylactic acid is relatively small, It is preferable to use it within the above-mentioned range because it is out of the range of the material content authentication.

In addition, the composite material composition of the present invention contains a polypropylene resin and a poly (lactic acid) resin as resin components, and contains a specific impact modifier, glass fiber, nucleating agent and compatibilizing agent in a certain amount as an additive.

Wherein the impact modifier is an ethylene copolymer comprising a poly (ethylene-n-butyl acrylate) copolymer prepared by copolymerizing 50 to 80% by weight of an ethylene monomer, 15 to 20% by weight of n-butyl acrylate and 1 to 10% by weight of glycidyl methacrylate, Butyl acrylate-glycidyl methacrylate). The impact modifier has a melt index (MI) of 2 to 10 g / 10 min (190 캜, 2.16 kg load). When the melt index is less than 2 g / 10 min, If the melt index exceeds 10 g / 10 min, the impact strength may also be lowered due to irregular dispersion of the dispersed phase during processing of the composite material. A uniformly dispersed morphology in the matrix resin of the impact modifier is one of the most important factors in improving the impact strength. The impact modifier may be used in an amount of 3 to 10 parts by weight based on 100 parts by weight of the resin component. If the content of the impact modifier is less than 3 parts by weight, the improvement in impact strength is remarkably reduced, so that it can not be applied to automobile parts. If the content of the impact modifier exceeds 10 parts by weight, there is a disadvantage that the application area is limited industrially have.

The glass fibers are short fibers having a length of 1 to 10 mm, and a cross-sectional diameter of 10 to 20 탆 is used. If the length of the glass fiber is less than 1 mm, uneven mixing and dispersion occurs during dry blending with other resins and additives in the extrusion mixing process, and the effect of improving the physical properties of the finally produced composite material can not be expected. The effect of improving the physical properties can not be expected due to uneven mixing. In addition, when the cross-sectional diameter of the organic fibers is less than 10 占 퐉 or exceeds 20 占 퐉, the effect of improving the physical properties of the final composite material is insufficient. The glass fiber is used in a range of 15 to 20 parts by weight based on 100 parts by weight of the resin component. If the content of the glass fiber is less than 15 parts by weight, the improvement of mechanical properties and heat resistance is insufficient. If the content of the glass fiber exceeds 20 parts by weight, only a part of the stiffness is increased, thereby adversely affecting the harmony of the whole properties.

The nucleating agent may be an aromatic sulfonic acid compound represented by the following general formula (2).

(Wherein R represents a phenyl group or a naphthalene group in which the alkyl group having 1 to 6 carbon atoms is substituted or unsubstituted)

The nucleating agent may include benzenesulfonic acid, 2-toluenesulfonic acid, 3-toluenesulfonic acid, 4-toluenesulfonic acid, naphthalenesulfonic acid, etc. These may be used alone or in admixture of two or more. The nucleating agent is used in an amount of 0.5 to 3 parts by weight based on 100 parts by weight of the resin component. If the content of the nucleating agent is less than 0.5 parts by weight, the molded article may not be smoothly taken out during injection molding. If the content of the nucleating agent is more than 3 parts by weight, the economical efficiency may be decreased.

The compatibilizer is a polypropylene resin grafted with maleic anhydride, and has a structure in which a polypropylene resin has a basic skeleton and maleic anhydride is chemically bonded to the side chain of the chain. The maleic anhydride grafted polypropylene resin has a weight average molecular weight (Mw) of 50,000 to 250,000 g / mol, and 0.1 to 5% by weight of maleic anhydride is grafted on the polypropylene resin. The compatibilizer enhances the contact between the resin component and the glass fiber. The compatibilizing agent is used in an amount of 1 to 10 parts by weight based on 100 parts by weight of the resin component, and is preferably limited to about 10 to 20% by weight relative to the weight of the polylactic acid resin used as the resin component. If the amount of the compatibilizing agent to be used is less than 1 part by weight based on 100 parts by weight of the resin component, an appropriate interfacial adhesion strength between the resin component and the organic fiber can not be obtained. If the amount exceeds 10 parts by weight, the maleic anhydride having a polarity different from that of the polypropylene resin, It is preferable to maintain the content ratio proposed by the present invention because the content of the polypropylene resin is relatively increased to deteriorate the mechanical properties of the finally produced composite material.

In addition, the composite material composition of the present invention may further contain other additives such as heat stabilizers, antioxidants, antioxidants, and photostabilizers which are conventionally used in the art as needed, and organic pigments, inorganic pigments , A dye, and the like.

Meanwhile, the present invention is characterized by a method for producing a composite material composition, which will be described in more detail as follows.

First, the polypropylene resin used as the resin component and the L- or D-poly lactic acid resin are melted and kneaded at a temperature of 190 to 210 ° C. At this time, if the temperature for melting and kneading is less than 190 캜, sufficient stirring and mixing may not be performed, and if it exceeds 210 캜, a part of polylactic acid resin may be thermally decomposed.

Then, the impact modifier, glass fiber, nucleating agent and compatibilizer used as additives are fed into the extruder mixing head or the side feeding device to prepare a composite material composition.

The composite material composition produced by the above-mentioned production method can be produced as a product by injection molding a specimen or a part in a general injection molding machine. That is, the composite material composition is injected into an injection molding machine and molded into a part, or after a part is formed, a heat treatment process in which the material is held in a convection oven at a temperature of 80 to 100 DEG C for 0.5 to 1 hour, or a mold temperature is maintained at a temperature of 80 to 110 DEG C, And can be made into final specimens or products.

The composite material produced through the above-described manufacturing method was excellent in various physical properties such as heat resistance, impact resistance, tensile strength and flexural strength. Therefore, the polypropylene-poly lactic acid composite material composition of the present invention can be substituted for a general-purpose polymer synthetic material.

The present invention will now be described in more detail with reference to the following examples, which should not be construed as limiting the invention thereto.

[Example]

Example 1

Polypropylene resin and L-poly lactic acid resin were kneaded as a resin component in a dry state and then put into a kneading machine and melted and kneaded at 195 캜. Composite specimens were prepared by injecting impact modifier, glass fiber, nucleating agent and compatibilizer into the mixing head at 100 ℃.

[Ingredients Used]

(1) Resin component

① Polypropylene (PP) resin: Melt index (MI) 20 g / 10 min (230 ° C, 2.16 kg load), product name TP-100, manufactured by Samil Polymer Co.,

(2) L-polylactic acid (PLLA) resin: melt index (MI) 10 g / 10 min (190 캜, 2.16 kg load), product name Ingeo 3251D, USA Nature Works

(2) Additives

(1) An impact modifier was prepared by copolymerizing poly (ethylene-n-butyl acrylate-glycidyl methacrylate) resin, 85% by weight of ethylene, 10% by weight of n-butyl acrylate and 5% by weight of glycidyl methacrylate Ethylene copolymer, melt index (MI) 5 g / 10 min (190 캜, 2.16 kg load), product name Elvaloy, DuPont

② Glass fiber: Short fiber with a length of 3 mm and a diameter of 10 ㎛, product name 183F-14P, Korea Owens Corning Co., Ltd.

③ Nucleating agent: benzenesulfonic acid, product name LAK-301, manufactured by Takemoto, Japan

④ Commercializer: polypropylene resin grafted with maleic anhydride, weight average molecular weight (Mw) of 70,000 g / mol, maleic anhydride graft rate of 3% by weight, product name PH-200,

Examples 2 to 4 and Comparative Examples 1 to 8

The same procedure as in Example 1 was carried out, except that the composite material specimens were produced by injection molding at the composition ratios shown in Table 1 below.

division Resin component (% by weight) Additive (parts by weight) ^* PP PLLA Impact modifier Glass fiber Nucleating agent Compatibilizer room
city
Yes One 70 30 10 15 One 3 2 65 35 5 20 One 3 3 65 35 5 15 One 3 4 70 30 5 20 One 3
ratio
School
Yes One 0 100 10 10 One 3 2 70 30 0 10 One 3 3 50 50 10 30 One 3 4 60 40 10 30 One 3 5 70 30 10 5 One 3 6 70 30 15 10 One 3 7 70 30 15 15 One 3 8 100 0 10 15 One 3 * Weight part: Amount of additive amount based on 100 parts by weight of resin component

[Experimental Example] Property measurement test

The properties of each of the composite material specimens prepared in Examples 1 to 4 and Comparative Examples 1 to 7 were measured by the following methods. The results are shown in Table 2 below.

1) Tensile Properties: Tensile strength was measured using a universal testing machine by making test specimens according to ASTM D 638 (Standard Test Method for Tensile Properties of Plastics).

 2) Impact strength: A specimen for measurement was prepared in accordance with ASTM D 256 (Standard Test Method for Tensile Properties of Plastics), and an impact strength was measured using an Izod impactor.

3) Heat Resistance: The heat distortion temperature was measured using a universal testing machine by making test specimens in accordance with ASTM D 648 (Standard Test Method for Deflection Temperature in Plastics Under Flexural Load in the Edgewise Position).

division Mechanical properties The tensile strength
(MPa) Flexural strength
(MPa) Flexural modulus
(MPa) Impact strength
(J / m) Heat resistance
(° C) room
city
Yes One 46 61 2993 76 153 2 45 60 2991 75 152 3 46 61 2990 75 153 4 45 60 2992 75 151 ratio
School
Yes One 39 54 2250 45 90 2 37 50 2360 44 105 3 35 51 2240 54 105 4 35 52 2320 50 90 5 37 50 2510 56 90 6 38 48 2410 60 121 7 35 46 2200 55 120 8 36 48 2100 70 120

As shown in Table 2, specific impact modifiers, glass fibers, nucleating agents and compatibilizers were mixed with a resin component composed of a polypropylene resin and an L- or D-poly lactic acid resin at a predetermined mixing ratio as proposed in the present invention (Examples 1 to 4) prepared from the composite specimens prepared in Examples 1 to 4 were superior in tensile strength, flexural strength, flexural modulus, impact strength, and heat resistance to those of Comparative Examples 1 to 7 It can be confirmed that the value is remarkably excellent.

Claims (10)

Based on 100 parts by weight of a resin component comprising 65 to 75% by weight of a polypropylene resin and 25 to 35% by weight of an L- or D-polylactic acid resin,
3 to 10 parts by weight of poly (ethylene-n-butyl acrylate-glycidyl methacrylate) having a melt index (MI) of 2 to 10 g / 10 min (190 캜, 2.16 kg load)
15 to 20 parts by weight of glass fiber having a length of 1 to 10 mm and a cross-sectional diameter of 10 to 20 占 퐉;
0.5 to 3 parts by weight of an aromatic sulfonic acid represented by the following formula (2); And
1 to 10 parts by weight of a polypropylene resin grafted with maleic anhydride;
Wherein the polypropylene-poly lactic acid composite material composition is a polypropylene-polylactic acid composite material composition.
(2)

(Wherein R represents a phenyl group or a naphthalene group in which the alkyl group having 1 to 6 carbon atoms is substituted or unsubstituted)
The method according to claim 1,
Wherein the polypropylene resin is a polypropylene homopolymer, a polypropylene block copolymer or a mixture thereof, and the polypropylene resin has a melt index (MI) of 10 to 40 g / 10 min (230 DEG C, 2.16 kg load) By weight based on the total weight of the polypropylene-polylactic acid composite material composition.
The method according to claim 1,
Wherein the polypropylene resin is a new product or a recycled product obtained by recovering a molded article of polypropylene which is discarded in an industrial field or a home.
The method according to claim 1,
Wherein the L- or D-poly lactic acid resin has a melt index (MI) of 5 to 40 g / 10 min (190 캜, 2.16 kg load).
The method according to claim 1,
Wherein the poly (ethylene-n-butyl acrylate-glycidyl methacrylate) comprises 50 to 80% by weight of an ethylene monomer, 15 to 20% by weight of n-butyl acrylate and 1 to 10% by weight of glycidyl methacrylate Polypropylene-polyglycolic acid composite material composition.
delete delete delete The method according to claim 1,
Wherein the polypropylene resin grafted with maleic anhydride has a weight average molecular weight (Mw) of 50,000 to 250,000 g / mol and 0.1 to 5% by weight of maleic anhydride grafted.
Melting and kneading a resin component having a ratio of 65 to 75% by weight of a polypropylene resin and 25 to 35% by weight of an L- or D-polylactic acid resin at a temperature of 190 to 210 ° C,
(Ethylene-n-butyl acrylate-glycidyl methacrylate) having a melt index (MI) of 2 to 10 g / 10 min (at 190 占 폚 under a load of 2.16 kg) 15 to 20 parts by weight of glass fibers having a diameter of 10 to 20 mu m, 0.5 to 3 parts by weight of an aromatic sulfonic acid represented by the following formula (2) 1 to 10 parts by weight of a polypropylene resin,
A process for producing a molded article by injection molding the composite material composition,
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(2)

(Wherein R represents a phenyl group or a naphthalene group in which the alkyl group having 1 to 6 carbon atoms is substituted or unsubstituted)