KR102133297B1 - Biodegradable film composite - Google Patents

Abstract

The present invention relates to a biodegradable film composition capable of being produced in various types of films, and a film produced from the composition, having polylactic acid, having eco-friendly properties, and having excellent impact resistance and moldability.

Description

Biodegradable film composition {BIODEGRADABLE FILM COMPOSITE}

The present invention relates to a biodegradable film composition capable of being produced in various types of films, and a film produced from the composition, having polylactic acid, having eco-friendly properties, and having excellent impact resistance and moldability.

Recently, as environmental pollution due to disposal of waste plastics has emerged as a serious social problem, biodegradable plastics are in the spotlight as eco-friendly resins. Accordingly, research has been actively conducted to apply biodegradable plastics to various fields including packaging containers and electronic product cases.

Commercially available biodegradable plastics are divided into those produced by synthesis and fermentation of natural products. In the case of synthetically produced aliphatic polyester-based biodegradable plastics, the price is very expensive, and the hardness and flexibility are high compared to conventional plastic products. There is a problem in that the field of use is limited because it can be applied only to an envelope.

On the other hand, polylactic acid, a biodegradable plastic produced by fermenting starch, has excellent transparency and is used for various purposes, including food packaging containers and medical materials. Polylactic acid has relatively high tensile strength and hardness compared to other biodegradable plastics, but lacks moldability, mechanical strength, and heat resistance, and has low resistance to temperature, resulting in deformation of the molded product when the external temperature rises above 60℃. There was.

In particular, since polylactic acid is easily damaged by impact, a thin portion is easily broken when manufactured in a film form, and there are many limitations in processing and use, such as a hole formed in a vacuum forming process. In addition, due to the thermal properties of the polylactic acid, the thermal deformation temperature is low and the shape stability is poor due to the slow cooling rate, and thus, there are many limitations in forming a shape by vacuum forming after film production.

In order to supplement the physical properties of polylactic acid and improve the functionality, a method of preparing a copolymer using polylactic acid, a method of blending with a general-purpose resin, a method of blending with engineering plastics such as polycarbonate, and a reinforcement material are introduced to the poly A method for improving the durability of lactic acid has been proposed.

However, despite this method, the application to applications requiring heat resistance and durability is insufficient due to the low crystallinity and slow crystallization rate of polylactic acid. Accordingly, there is a need to develop a polylactic acid having excellent mechanical properties applicable to various fields while maintaining biodegradability and eco-friendliness.

Korean Registered Patent No. 10-1545932

The present invention for solving the above problems, provides a biodegradable film composition and a film prepared therefrom that is polylactic acid, has eco-friendly properties, has excellent impact resistance and moldability, and can be manufactured into various types of films. There is a purpose.

The composition for a film according to the present invention for achieving the above object includes a polylactic acid, an acrylate-based polymer composed of a core-shell structure, and a plasticizer.

In one aspect of the present invention, the core of the acrylate-based polymer composed of the core-shell structure may include a copolymer of an acrylate and an aromatic vinyl-based monomer, and the shell comprises a copolymer of acrylate and methacrylate. It may be included.

In one embodiment of the present invention, the core copolymer comprises 60 to 90% by weight of acrylate and 10 to 40% by weight of aromatic vinyl-based monomer relative to the total monomer, and the shell copolymer 10 to acrylate relative to the total monomer It may be to include 50% by weight and 50 to 90% by weight of methacrylate.

In one aspect of the present invention, the aromatic vinyl-based monomer may be any one or two or more mixtures selected from styrene, α-methylstyrene, ο-ethylstyrene, p-ethylstyrene, vinyltoluene, and derivatives thereof.

In one aspect of the present invention, the core and the shell may include a crosslinking agent.

In one aspect of the present invention, the core-shell structured acrylate-based polymer may have a core of 30 to 50% by weight and a shell of 50 to 70% by weight.

In one embodiment of the present invention, the composition for the film may be 30 to 89% by weight of polylactic acid, 10 to 50% by weight of an acrylate-based polymer composed of a core-shell structure, and 1 to 50% by weight of a plasticizer.

Another aspect of the present invention is a film produced by thermally processing the composition for a film.

Another aspect of the present invention comprises the steps of a) preparing an acrylate-based polymer composed of a core-shell structure; b) preparing a film by melt-kneading the acrylate-based polymer, polylactic acid, and a plasticizer; and related to a method of manufacturing a polylactic acid film.

In one aspect of the present invention, the step a) comprises the steps of forming a core by emulsion polymerization of acrylate and aromatic vinyl monomers; And adding acrylate and methacrylate to the core and emulsion-polymerizing to form a shell.

In one aspect of the present invention, the step of forming the core and shell may be emulsion polymerization in the presence of a crosslinking agent.

When a film is prepared using the biodegradable film composition according to an aspect of the present invention, biodegradation by microorganisms and the like can be easily performed, and thus there is an advantage of not causing environmental pollution upon disposal.

In addition, the biodegradable film composition according to an aspect of the present invention has the advantage of expanding the application field of the biodegradable film, as it is possible to manufacture in various film forms because of its excellent processability.

In addition, the biodegradable film composition according to an aspect of the present invention has no effect of whitening and haze, has excellent transparency, and has an effect of significantly improving mechanical properties such as tensile strength and impact strength.

Hereinafter, the present invention will be described in more detail through specific examples or examples. However, the following specific examples or examples are only one reference for explaining the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

Also, unless defined otherwise, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the present invention is merely for effectively describing a specific embodiment and is not intended to limit the present invention.

In the present invention, a copolymer means that an element referred to as a monomer in the present invention is polymerized and included as a repeating unit in the copolymer resin. In the present invention, the copolymer may be a block copolymer or a random copolymer. , But is not limited thereto.

The present invention for achieving the above object relates to a composition for a film comprising a polylactic acid, an acrylate-based polymer composed of a core-shell structure and a plasticizer, a biodegradable film prepared by heat processing it, and a method for manufacturing the same.

The present invention will be described in detail as follows.

The composition for a film according to the present invention includes a polylactic acid, an acrylate-based polymer composed of a core-shell structure, and a plasticizer, thereby improving the low mechanical properties inherent to conventional polylactic acid to ensure stable mechanical strength, Processability can be remarkably improved. Accordingly, it is possible to manufacture in the form of a film while maintaining eco-friendliness according to the biodegradable properties of polylactic acid, and can be applied by replacing general-purpose resin in various fields.

In one aspect of the present invention, the polylactic acid is a resin that provides biodegradability and eco-friendliness of the film, and is polymerized from monomers derived from D-Lactide or L-Lactide. The polylactic acid produced can be used without limitation.

In addition, the di-lactide (D-Lactide) and L-lactide (L-Lactide) may be to use a polylactic acid that is polymerized by freely using the content, the di-lactide (D-Lactide) content It may be a mixture of crystalline polylactic acid present in 1 to 5% by weight and amorphous polylactic acid having a di-lactide content of 9% by weight or more.

When the polylactic acid is used in combination as described above, the impact resistance and heat resistance of the crystalline polylactic acid are exhibited, and at the same time, the flexibility by the amorphous polylactic acid is imparted, so that properties of each other can be improved as properties of each other complement each other. have.

In addition, the polylactic acid may have a weight average molecular weight of 10,000 to 500,000 g/mol, specifically 50,000 to 400,000 g/mol, and more specifically 100,000 to 350,000 g/mol, but is not limited thereto.

The polylactic acid has an environmentally friendly property that can be easily decomposed in the natural environment even when discarded, compared to a petroleum-based resin, the amount of environmentally harmful substances is significantly lower during use or disposal.

In particular, as the polylactic acid is used together with an acrylate-based polymer and a plasticizer made of the core-shell structure of the present invention, the processability of the polylactic acid is significantly improved, thereby making it easy to produce a film, and the film produced therefrom. Silver has biodegradable properties, as well as transparency and excellent mechanical properties.

In one aspect of the present invention, the core of the acrylate-based polymer composed of the core-shell structure includes a copolymer of an acrylate and an aromatic vinyl-based monomer, and the shell comprises a copolymer of acrylate and methacrylate. Can.

In one aspect of the invention, the acrylate monomer may be a C1-C10 alkyl acrylate, for example, methyl acrylate, ethyl acrylate?, n-butyl acrylate, t-butyl acrylate and 2-ethyl It may be any one or a mixture of two or more selected from hexyl acrylate.

In one aspect of the present invention, the aromatic vinyl-based monomer may be any one or two or more mixtures selected from styrene, α-methylstyrene, ο-ethylstyrene, p-ethylstyrene, vinyltoluene, and derivatives thereof.

In one aspect of the present invention, the core and the shell may further include an initiator, and are not particularly limited as an initiator, but are specifically selected from potassium persulfate, sodium persulfate, lithium persulfate and iron sulfate. Select from sulfates, 2,2'-azo-bis(isobutyronitrile), 2,2'-azo-bis(2,4-dimethylvaleronitrile) and 1-t-butyl-azocyanocyclohexane Azo, t-butyl hydroperoxide and cumene hydroperoxide, diisopropyl benzene hydroperoxide, paramethane hydroperoxide, benzoyl peroxide, caprylyl peroxide, di-t-butyl peroxide, ethyl 3 ,3'-di(tbutylperoxy) butyrate, ethyl 3,3'-di(t-amylperoxy) butyrate, t-amylperoxy-2-ethyl hexanoate and t-butylperoxy valate Peroxides selected from peroxides, t-butyl peracetate, t-butyl perphthalate and t-butyl perbenzoate, and di(1-cyano-1-methylethyl)peroxy dicarbonate. Percarbonates and the like may include any one or two or more mixtures.

In one aspect of the present invention, the initiator may include 0.01 to 10 parts by weight, preferably 0.01 to 5 parts by weight, based on 100 parts by weight of the total monomer of the core or shell, but is not limited thereto.

In one embodiment of the present invention, the core may be an acrylate-based copolymer polymerized from a core composition comprising an acrylate, an aromatic vinyl-based monomer, and an initiator, and the copolymer is 60 to 90 wt. % And 10 to 40% by weight of an aromatic vinyl monomer. Preferably, it may be 70 to 90% by weight of acrylate and 10 to 30% by weight of aromatic vinyl monomer. The copolymer containing the above content is excellent in compatibility with the shell formed on the outside of the core, and thus has improved binding properties, thereby improving long-term stability and impact resistance.

In one aspect of the present invention, the shell may be an acrylate-based copolymer polymerized from a shell composition comprising an acrylate, methacrylate and an initiator, and the copolymer is 10 to 50% by weight of acrylate based on the total monomer. And 50 to 90% by weight of methacrylate. Preferably it may be one containing 10 to 30% by weight of acrylate and 70 to 90% by weight of methacrylate. The copolymer containing the above content is excellent in compatibility with the shell, as well as the compatibility with polylactic acid, thereby improving the mechanical properties of the film produced therefrom.

In one embodiment of the present invention, the core-shell structured acrylate polymer has a core of 30 to 50% by weight, a shell of 50 to 70% by weight, preferably a core of 40 to 50% by weight, and a shell It may be 60 to 70% by weight. At this time, the shell may be made of not only a single layer, but also a multilayer of two or more layers.

In the acrylate-based polymer made of the core-shell structure according to the present invention, each core and shell constituting the polymer are prepared with a monomer content in the above range, and cores and shells prepared therefrom are included in the content in the above range and core- As the shell structure is formed, an effect of significantly improving the impact resistance of the film is imparted. In addition, the acrylate-based polymer has excellent compatibility with polylactic acid, and improves the processability of polylactic acid, thereby providing an effect that can be produced in a film form without deteriorating transparency.

In one aspect of the present invention, the core may optionally include a crosslinking agent.

In one embodiment of the present invention, the crosslinking agent is 1,2-ethanediol dimethacrylate, 1,2-ethanedioldiacrylate, 1,3-propanediol dimethacrylate, 1,3-propanediol diacrylate Rate, 1,4-butanediol dimethacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol dimethacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol dimethacrylate Acrylate, 1,6-hexanediol diacrylate, divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, propylene glycol dimethacrylate, propylene glycol diacrylate, butylene glycol dimethacrylate , Butylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, polypropylene glycol dimethacrylate, polypropylene glycol diacrylate , Polybutylene glycol dimethacrylate, polybutylene glycol diacrylate, allyl methacrylate, and allyl acrylate.

In addition, the crosslinking agent may contain 0.1 to 10 parts by weight based on 100 parts by weight of the total monomer of the core. Preferably it may contain 0.1 to 5 parts by weight based on 100 parts by weight of the monomer mixture. When the core contains a crosslinking agent in the above content, an acrylate polymer having a core-shell structure having a core of a crosslinked acrylic copolymer can be prepared, and impact resistance, etc. as the monomers are crosslinked as described above Mechanical properties of can be further improved. In particular, it is very effective in improving the workability by reinforcing the strength of polylactic acid.

In one aspect of the present invention, the acrylate-based polymer composed of the core-shell structure may be in the form of particles having an average particle diameter of 10 to 500 nm, preferably the average particle diameter may be 50 to 200 nm, It is not limited.

In one aspect of the present invention, the plasticizer further improves the molding processability of the film, softens polylactic acid by using it with an acrylate-based polymer composed of the core-shell structure, increases thermoplasticity and facilitates processing at an appropriate temperature. It gives the effect that can be done. In particular, it is possible to improve the compatibility of the acrylate-based polymer and polylactic acid and improve the mechanical properties of the film more stably without whitening.

The plasticizer is not limited as long as it is a commonly used plasticizer, and specifically, for example, a phthalate plasticizer and an isophthalate plasticizer may be used, and more specifically, dioctylphthalate (DOP), dipropylheptyl phthalate (DPHP) And diisodecyl phthalate (DIDP).

In one embodiment of the present invention, the composition for the film may be 30 to 89% by weight of polylactic acid, 10 to 50% by weight of an acrylate-based polymer composed of a core-shell structure, and 1 to 50% by weight of a plasticizer. Preferably, 40 to 85% by weight of polylactic acid, 10 to 40% by weight of an acrylate-based polymer composed of a core-shell structure, and 5 to 20% by weight of a plasticizer may be included, but is not limited thereto.

As the composition for a film according to the present invention contains the content in the above range, the processability of polylactic acid is secured and the impact resistance is improved without deterioration of physical properties of excellent optical properties, and it is not easily broken even during processing, and an effect of manufacturing a film with excellent smoothness is possible. There is. Accordingly, the polylactic acid film can be extruded and calendered to facilitate production in various forms, thereby expanding the application field of the biodegradable film.

Another aspect of the present invention is a film produced by thermally processing the composition for a film. The composition for a film may be melt-kneaded to form a film, and the prepared film is a biodegradable film having excellent optical properties and improved tensile strength and impact resistance.

Another aspect of the present invention comprises the steps of a) preparing an acrylate-based polymer composed of a core-shell structure; b) preparing a film by melt-kneading the acrylate-based polymer, polylactic acid, and a plasticizer;

In one aspect of the present invention, the step a) comprises the steps of forming a core by emulsion polymerization of acrylate and aromatic vinyl monomers; And adding acrylate and methacrylate to the core and emulsion-polymerizing to form a shell.

Specifically, the emulsion polymerization for the production of an acrylate-based polymer composed of the core-shell structure of step a) may be performed through a conventional emulsion polymerization method, and the core is an acrylate and aromatic vinyl monomer under a nitrogen atmosphere. It may be an emulsion polymerization including a core composition and an emulsifier containing, after the shell composition and an emulsifier containing acrylate and methacrylate are added to emulsify and polymerize the shell to form a shell, and then aggregate, Dehydration and drying may produce an acrylate-based polymer having a core-shell structure.

In one embodiment of the present invention, the emulsifier may be to use an anionic emulsifier such as an alkali alkyl phosphate of C4-C30, sodium dodecyl sulfate, sodium dodecylbenzene sulfate and alkyl sulfate salt, but is not limited thereto. The emulsifier may include 0.01 to 5 parts by weight based on 100 parts by weight of the monomer mixture of each core and shell, but is not limited thereto.

In one aspect of the present invention, the step of forming the core and the shell may be emulsion polymerization in the presence of a crosslinking agent, and the type and content of the crosslinking agent are as described above.

In one embodiment of the present invention, step b) is a step of melting and kneading an acrylate-based polymer, polylactic acid, and a plasticizer composed of a core-shell structure into a film, and is not particularly limited in the method of manufacturing the film. .

Specifically, for example, the acrylate-based polymer, polylactic acid, and a plastic composition are uniformly mixed, and the mixed mixture is kneaded at a temperature of 130 to 250°C to prepare a film through a known molding method. The molding may be performed by any one or two or more methods selected from a melt casting method, a T-die method and a calendar method.

In one embodiment of the present invention, the step b) may be melt-kneaded by further including any one or more additives selected from lubricants, antioxidants, and UV stabilizers.

The lubricant is a fatty acid-based compound such as stearic acid, a fatty acid ester-based compound such as butyl ester or octyl stearate, a fatty acid and a mixture of alcohol such as palmityl alcohol or stearyl alcohol, a fatty acid amide compound such as stearic acid amide or oleic acid amide, Hydrocarbon-based compounds such as metallic soaps, paraffins, or polyethylene waxes, or mixtures thereof, and may be used in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the film composition, but are not limited thereto.

The antioxidant may include a primary antioxidant functioning as a radical scavenger and a secondary antioxidant functioning as a peroxide decomposition agent. Specifically, for example, (3,5-di-t-butyl-4-hydrocyhydrocinnamate)methane as the primary antioxidant ((3,5-di-t-butyl-4-hydroxyhydrocinna mate)methane) As a secondary antioxidant, tris(2,4-di-t-butylphenyl)phosphite (Tris(2,4-di-t-butylphenyl)phosphite) may be mentioned, 0.1 per 100 parts by weight of the film composition It may be used in 1 part by weight, but is not limited thereto.

The ultraviolet stabilizer may be any one or a mixture of two or more selected from benzophenone compounds, benzotriazole compounds, aromatic benzoate compounds, oxalic acid anilide compounds, cyanoacrylate compounds and hindered amine compounds, etc. The composition may be used in an amount of 0.1 to 5 parts by weight based on 100 parts by weight, but is not limited thereto.

Through the steps a) and b), it is possible to significantly improve the low mechanical properties and processability inherent to polylactic acid, and the polylactic acid film produced therefrom exhibits excellent tensile strength and impact resistance. In addition, it is possible to manufacture a film having excellent smoothness without deterioration and whitening of optical properties such as haze and light transmittance, and thus has an advantage of expanding the application field of the biodegradable film.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples. However, the following examples and comparative examples are only examples for explaining the present invention in more detail, and the present invention is not limited by the following examples and comparative examples.

[Method of measuring properties]

1. Film durability

After leaving the film for 6 months, whether it is cracked when it is bent 180° is shown below.

Good: The film does not break.

Poor: The film is broken.

2. White Flower

The film is folded 180° at room temperature, bent, and the whitening state is observed to be shown below.

○: White flowers were not recognized.

△: Some white flowers were recognized.

X: Whitening is remarkable.

3. Processability

The calendering processability was evaluated and shown as follows.

○: When calendering, it does not stick to the roll and can be continuously processed without breaking.

△: Partly stuck to the roll or trimmed during calendering.

X: Calendaring processing is impossible.

4. Tensile strength

It was measured according to the ASTM D638 test method using a universal testing machine (UTM, Zwick).

5. Haze and light transmittance (%)

It was measured by Hazemeter according to ASTM D1003 method.

[Production Example 1]

In order to form the core of the acrylate-based polymer, 250 parts by weight of ion-exchanged water, 0.002 parts by weight of ferrous sulfate, 0.008 parts by weight of EDTA·2Na salt, 0.2 parts by weight of sodium formaldehyde sulfoxide in a 5 L reactor with a stirrer attached And 2 parts by weight of sodium dodecyl sulfate, and after nitrogen substitution, heated to 65°C.

After heating, a mixed solution consisting of 33 parts by weight of butyl acrylate, 7 parts by weight of styrene, 1 part by weight of allyl methacrylate, and 0.05 parts by weight of cumene hydroperoxide was added dropwise for 120 minutes, followed by emulsion polymerization with stirring for 1 hour. The average diameter of the obtained core particles was 40 nm.

Next, 0.5 parts by weight of sodium dodecyl sulfate, 6 parts by weight of butyl acrylate, 24 parts by weight of methyl methacrylate, 0.3 parts by weight of allyl methacrylate, 0.04 parts by weight of dodecyl mercaptan, cumenehydride in the obtained core particles After adding 0.05 parts by weight of loper oxide mixed solution over 1 hour, 3 parts by weight of butyl acrylate, 27 parts by weight of methyl methacrylate, 0.09 parts by weight of dodecyl mercaptan and 0.05 parts by weight of cumene hydroperoxide Was added dropwise over 1 hour and then polymerized for 1 hour. The average diameter of the core-shell structured particles obtained at this time was 60 nm.

Subsequently, in order to agglomerate the acrylate-based polymer having the core-shell structure, 0.02 parts by weight of calcium acetate was added to 100 parts by weight of solid particles to aggregate, and the resulting particle powder was dehydrated in distilled water and then dried at 80°C. .

[Example 1]

40% by weight of polylactic acid, 40% by weight of the polymer of the core-shell structure prepared from Preparation Example 1 and 20% by weight of dioctylphthalate as a plasticizer were added to a Banbury mixer and kneaded at 140°C for 5 minutes. A uniformly mixed composition was prepared. Next, a film was prepared by using the kneaded composition at a calender roll of 130°C. Subsequently, after preheating at a press of 50 kgf/cm 3 for 3 minutes, pressurized to 200 kgf/cm 3 and pressed for 5 minutes, cooled to 40° C. or less to prepare a film having a final thickness of 0.5 mm. To evaluate the physical properties of the prepared film is shown in Table 1 below.

[Example 2]

In Example 1, except that the composition was prepared using 50% by weight of polylactic acid, 40% by weight of the polymer having a core-shell structure of Preparation Example 1, and 10% by weight of dioctylphthalate, the same procedure as in Example 1 was performed. A film with a thickness of 0.5 mm was prepared. To evaluate the physical properties of the prepared film is shown in Table 1 below.

[Example 3]

In Example 1, except that the composition was prepared using 70% by weight of polylactic acid, 20% by weight of the polymer having a core-shell structure of Preparation Example 1, and 10% by weight of dioctylphthalate, the same procedure as in Example 1 was carried out. A film with a thickness of 0.5 mm was prepared. To evaluate the physical properties of the prepared film is shown in Table 1 below.

[Example 4]

In Example 1, except that the composition was prepared using 85% by weight of polylactic acid, 10% by weight of a polymer having a core-shell structure of Preparation Example 1, and 5% by weight of dioctylphthalate, the same procedure as in Example 1 was performed. A film with a thickness of 0.5 mm was prepared. To evaluate the physical properties of the prepared film is shown in Table 1 below.

[Comparative Example 1]

A film having a thickness of 0.5 mm was prepared in the same manner as in Example 1, except that a film was prepared using only polylactic acid as the film composition in Example 1. To evaluate the physical properties of the prepared film is shown in Table 1 below.

[Comparative Example 2]

In Example 1, a polylactic acid film having a thickness of 0.5 mm was prepared in the same manner as in Example 1, except that a film was prepared using 80% by weight of polylactic acid and 20% by weight of dioctylphthalate as a film composition. Did.

[Comparative Example 3]

In Example 1, except that a film was prepared using 70% by weight of polylactic acid as a film composition and 30% by weight of a polymer having a core-shell structure prepared from Preparation Example 1, the thickness was performed in the same manner as in Example 1 A polylactic acid film having a thickness of 0.5 mm was prepared.

[Comparative Example 4]

In Example 1, except that the composition was prepared using 70% by weight of polylactic acid, 20% by weight of Mitsubishi Chemical's Metablen W-300A and 10% by weight of dioctylphthalate, the thickness was performed in the same manner as in Example 1 A 0.5 mm film was prepared. To evaluate the physical properties of the prepared film is shown in Table 1 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 durability Good Good Good Good Good Good Bad Bad colloquial Chinese ○ ○ ○ ○ ○ ○ △ Х Processability ○ ○ ○ ○ Х △ △ ○ The tensile strength
(kgf/cm ² ) 250 300 320 330 50 20 250 350 Hayes 1.0 0.9 0.9 1.0 1.0 1.0 2.0 5.0 Light transmittance (%) 93 93 93 93 93 92 90 85

As shown in Table 1, Examples 1 to 4, as well as exhibiting excellent optical properties and durability without whitening, it was confirmed that the processability and tensile strength was greatly improved.

On the other hand, it can be seen that the polylactic acid film according to Comparative Example 1 cannot be calendered and has low tensile strength, and the film according to Comparative Example 2 has poor workability and significantly lower tensile strength. In addition, in Comparative Examples 3 and 4, whitening occurred on the film, and it was confirmed that the film breaks when bent after 6 months of standing.

Claims (11)

As a composition for a film composed of a polylactic acid, an acrylate-based polymer composed of a core-shell structure and a plasticizer,
The core of the acrylate-based polymer composed of the core-shell structure includes a copolymer of an acrylate and an aromatic vinyl-based monomer, and the shell includes a copolymer of an acrylate and a methacrylate,
A composition for a film having no deterioration in light transmittance of a film made of the film composition compared to a light transmittance of a film made using polylactic acid alone. delete According to claim 1,
The core copolymer includes 60 to 90% by weight of acrylate and 10 to 40% by weight of aromatic vinyl-based monomer relative to the total monomer, and the shell copolymer is 10 to 50% by weight of acrylate and methacrylate relative to the total monomer. Composition for a film comprising 50 to 90% by weight. According to claim 1,
The aromatic vinyl-based monomer is a styrene, α- methyl styrene, ο- ethyl styrene, p- ethyl styrene, vinyl toluene and any one or more mixtures selected from derivatives thereof for the film composition. According to claim 1,
The core and shell composition for a film comprising a crosslinking agent. According to claim 1,
The acrylate-based polymer composed of the core-shell structure has a core of 30 to 50% by weight, and a shell having a composition of 50 to 70% by weight. According to claim 1,
The film composition is a composition for a film comprising 30 to 89% by weight of polylactic acid, 10 to 50% by weight of an acrylate-based polymer composed of a core-shell structure, and 1 to 50% by weight of a plasticizer. A film produced by thermally processing a composition for a film according to any one of claims 1 to 3 to 7. According to claim 1,
The film composition is a composition for a film that further comprises any one or more additives selected from lubricants, antioxidants and UV stabilizers. delete delete