KR102160702B1 - Acrylic impact modifier, polylatic acid resin composition comprising the same - Google Patents

Abstract

The present invention relates to an acrylic impact modifier and a polylactic acid resin composition comprising the same, and more particularly, an acrylic impact modifier capable of simultaneously increasing transparency and impact strength by designing the composition of each monomer constituting the sheath, core and shell, and It relates to a polylactic acid resin composition comprising the same.

Description

Acrylic impact modifier, polylatic acid resin composition comprising the same}

The present invention relates to an acrylic impact modifier and a polylactic acid resin composition comprising the same, which enables the manufacture of a molded article having excellent impact strength and transparency.

Polylactic acid (PLA) is a linear aliphatic polyester and is a thermoplastic polymer material synthesized using monomers obtained from 100% renewable resources such as corn and potato starch.

Polylactic acid is widely used to account for 20% of the total bioplastics market due to its low price and excellent properties compared to other existing biodegradable plastics. Its uses are spreading to automobile parts, electric and electronic parts, mobile phones, automobile interior materials, and industrial parts.

Existing polylactic acid resins lack moldability, mechanical strength, and heat resistance, so thin-film products are easily damaged, and their resistance to temperature is low, so when the external temperature rises above 60℃, deformation occurs in the shape of the molded product. there was.

Recently, in order to supplement the physical properties of polylactic acid and improve its functionality, a method of blending with a general-purpose resin, a method of blending with engineering plastics, and a composite method of introducing a reinforcing material such as a filler have been proposed.

In order to improve the durability of polylactic acid, a method of blending with general-purpose resins or engineering plastics such as PC and ABS (Acrylonitrile-Butadiene-Styrene) or adding additives such as impact modifiers has been proposed. It is generally used.

Japanese Patent Application Laid-Open No. 2015-147853 discloses the use of a core-shell type impact modifier in a polylactic acid resin. At this time, the core-shell type impact modifier is an unsaturated carboxylic acid alkyl ester monomer, a glycidyl group-containing vinyl monomer, an aliphatic vinyl monomer, an aromatic vinyl monomer, in a core including a butadiene rubber, an acrylic rubber, and a silicone rubber. A structure in which a shell is formed by polymerization of a vinyl cyanide unit, a maleimide monomer, an unsaturated dicarboxylic acid monomer, an unsaturated dicarboxylic anhydride monomer, etc. is presented.

Although it is possible to improve the impact resistance of the polylactic acid resin through the use of such a core-shell type impact modifier, the transparency of the molded article made of the polylactic acid resin decreases due to the use of the impact modifier.

The content of the impact modifier was adjusted to improve the transparency, but this again caused a new problem of lowering the impact strength. Accordingly, a technology proposal that can simultaneously improve transparency and impact strength is required.

Polylactic acid is recognized as a remarkable material in conjunction with environmental regulatory policies that are spreading domestically and around the world. As usage is expected to increase in the future, a new method to increase transparency and impact strength at the same time is very much suggested. It is urgent.

Japanese Patent Laid-Open No. 2015-147853 (2015.08.20), polylactic acid resin composition and molded article

Accordingly, the inventors of the present invention conducted various studies in order to solve the above problem. As a result, when manufacturing an impact modifier having a seed-core-shell structure, the refractive index of the seed, core and shell was adjusted similarly to that of polylactic acid resin to increase transparency. , When manufacturing the core, the present invention was completed by confirming that the degree of crosslinking and the impact strength were improved by using a polyalkylene glycol monomer, and the compatibility with the polylactic acid resin can be improved by using an epoxy monomer in the shell. .

Accordingly, an object of the present invention is to provide an acrylic impact modifier having a core-cell structure made of a specific composition.

In addition, another object of the present invention is to provide a polylactic acid resin composition having improved transparency and impact strength, including the acrylic impact modifier.

In order to achieve the above object, the present invention is based on 100% by weight of the total monomers constituting the acrylic impact modifier

6.5 to 15% by weight of a seed polymerized with an alkyl acrylate monomer;

63.5 to 75% by weight of an acrylic core copolymerized with an alkyl acrylate and a polyalkylene glycol-based monomer on the seed; And

It surrounds the acrylic core, and provides an acrylic impact modifier comprising 10 to 30 wt% of a shell in which methyl methacrylate and an epoxy monomer are copolymerized.

The seed is characterized in that 6.5 to 13.5% by weight of an alkyl acrylate monomer is single-polymerized or further copolymerized with 1.5% by weight or less of a methyl methacrylate monomer as a comonomer.

In addition, the acrylic core is characterized in that 63.4 to 74% by weight of an alkyl acrylate and 0.1 to 1% by weight of a polyalkylene glycol-based monomer are polymerized.

In addition, the shell is characterized in that 9 to 20% by weight of methyl methacrylate and 1 to 10% by weight of an epoxy monomer are polymerized.

At this time, the acrylic impact modifier is characterized in that the average particle diameter is 180 to 260nm.

In addition, the present invention provides a polylactic acid resin composition comprising the acrylic impact modifier.

The acrylic impact modifier according to the present invention has excellent compatibility with the resin as well as excellent impact strength and transparency when used as an additive for a polylactic acid resin by producing a seed-core- and a shell using a monomer of a specific composition. It enables the manufacture of molded polylactic acid resin products.

Hereinafter, the present invention will be described in more detail.

Acrylic impact modifier

In the present invention, the present invention relates to an acrylic impact modifier used for polylactic acid resin, and is used in the molding process of polylactic acid resin by designing the composition of each of the monomers constituting the sheath, acrylic core, and shell to increase impact strength and transparency and improve compatibility. We present an impact modifier that can be improved.

The improvement of transparency can be improved by adjusting the refractive index of the polylactic acid resin and the acrylic impact modifier to be the same or almost similar, and the impact strength can be improved by adjusting the composition of the acrylic core and the compatibility of the shell in direct contact with the polylactic acid. have.

The refractive index of polylactic acid resin is known to be about 1.45 to 1.48, and polymethyl methacrylate generally used for graft shells to secure compatibility of acrylic impact modifiers has a refractive index of 1.489, which is higher than that of polylactic acid resins. When used alone, a high level of transparency cannot be secured. Accordingly, the acrylic impact modifier presented in the present invention is designed to have the same or equivalent refractive index as the polylactic acid resin in the composition of the acrylic core and shell to ensure transparency, but to have a high level of impact strength for use as an impact modifier. The type and content ratio of the monomers constituting the reinforcing agent are limited.

The seeds are fine particles for preparing an acrylic core, and are prepared by emulsion polymerization of an alkyl acrylate monomer and a methyl methacrylate monomer.

The alkyl acrylate monomer may be at least one selected from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and stearyl acrylate, and preferably polylactic acid Use of butyl acrylate, which has a similar refractive index to the resin and has a low Tg.

The content ratio of the alkyl acrylate and methyl methacrylate is adjusted to have a refractive index similar to that of the polylactic acid resin and have excellent transparency, impact strength, and stability of latex.

Preferably, the seed is contained in an amount of 6.5 to 15% by weight within 100% by weight of the monomers constituting the total acrylic impact modifier. The content of the seed affects the final particle size of the acrylic impact modifier, and specifically, if the content is less than the above range, the final particle size increases, which may reduce transparency and latex stability, and on the contrary, it may exceed the above range. In this case, since the final particle size decreases and the impact strength decreases, or the acrylic shell does not sufficiently cover the seed and the core, the shell thickness decreases and the compatibility may decrease. Therefore, it is appropriately used within the above range.

More specifically, the seed is used as an alkyl acrylate monomer in an amount of 6.5 to 13.5% by weight, preferably 7 to 13% by weight, for homopolymerization, or 1.5% by weight or less as a comonomer, preferably 0.5 to 1% by weight of methylmetha It is used by copolymerizing with acrylate. If an alkyl acrylate monomer and methyl methacrylate content outside the above range is used, it is difficult to secure transparency, impact strength, and latex stability.

The acrylic core is formed to surround the seed, and is prepared through emulsion polymerization of an alkyl acrylate and a polyalkylene glycol-based monomer.

The acrylic core is designed to have a refractive index similar to that of the polylactic acid resin, but a monomer that is easily crosslinked must be used to surround the seed well, and has a high impact strength to exhibit physical properties as an impact modifier. The composition is limited so that the compatibility with the monomer used for is also high.

To suit this purpose, alkyl acrylate and polyalkylene glycol monomers were selected as monomers, and the content of alkyl acrylate was 63.4 to 74% by weight, preferably 64.4 to 73% by weight, so as to increase transparency and impact strength. And, in order to increase compatibility with the shell, the content of the polyalkylene glycol-based monomer is limited to 0.1 to 1% by weight, preferably 0.3 to 0.8% by weight.

Alkyl acrylate used as the acrylic core follows what was mentioned in the above seed, and preferably, butyl acrylate having a similar refractive index to polylactic acid resin and low Tg is used.

In addition, polyalkylene glycol-based monomers that can be used include, for example, poly(ethylene glycol) monoacrylate, poly(ethylene glycol) monomethacrylate, poly(propylene glycol) monoacrylate, and poly(propylene glycol) monomethacrylate. , Poly(ethylene glycol) diacrylate, poly(ethylene glycol) dimethacrylate, poly(propylene glycol) diacrylate, poly(propylene glycol) dimethacrylate, methoxy poly(ethylene glycol) monoacrylate, Methoxy (ethylene glycol) monomethacrylate, methoxy poly (propylene glycol) monoacrylate, methoxy poly (propylene glycol) monomethacrylate, phenoxy poly (ethylene glycol) monoacrylate, phenoxy poly (ethylene) Glycol) may be one or more selected from the group consisting of monomethacrylate, phenoxy poly(ethylenepropylene) monoacrylate, and phenoxy poly(ethylenepropylene) monomethacrylate, preferably polyethylene glycol diacrylate. do.

At this time, the polyalkylene glycol-based monomer is a polymer and may have a number average molecular weight (Mn) of 200 to 10,000 g/mol, or 200 to 1,000 g/mol.

The acrylic core comprising the above composition is included in an amount of 63.5 to 75% by weight within 100% by weight of the monomers constituting the total acrylic impact modifier. If the content is less than the above range, there is a problem that the impact is lowered because the rubbery property capable of absorbing the impact is small. On the contrary, when the content exceeds the above range, the content of the shell is relatively reduced, resulting in compatibility with polylactic acid resin and Since the acidity is lowered and there is a possibility that a problem of processing may occur, it is appropriately used within the above range.

In addition, the acrylic impact modifier according to the present invention forms a shell to surround the acrylic core, wherein the shell has a refractive index similar to that of the polylactic acid resin, and the composition of the monomer is limited in consideration of compatibility thereof.

Specifically, the shell is prepared through emulsion polymerization of methyl methacrylate and an epoxy-based monomer.

Through the use of methyl methacrylate, it is possible to manufacture a shell having high impact resistance and transparency, and an epoxy-based monomer is used to increase compatibility with this polylactic acid resin.

Epoxy-based monomers contain epoxy functional groups present in the molecular structure, and these functional groups induce a reaction in the melt-mixing process with the carboxyl groups of polylactic acid to improve compatibility between acrylic impact modifiers and polylactic acid resins. It plays a role in improving processability.

The usable epoxy monomer is preferably at least one selected from the group consisting of glycidyl methacrylate, triglycidyl isocyanurate, bis(4-epoxycyclohexylmethyl) adipate, and cyclooctadiene diepoxide. The following, more preferably glycidyl methacrylate is used.

In the shell of the acrylic impact modifier, methyl methacrylate is used in an amount of 9 to 20% by weight, preferably 11 to 18% by weight, and the epoxy-based monomer is 1 to 10% by weight, preferably 2 to 8% by weight. Used as %. If the content of methyl methacrylate is less than the above range, impact resistance cannot be achieved, and if the content of the methyl methacrylate exceeds the above range, the content of the epoxy-based monomer is relatively reduced, so that compatibility and transparency with the polylactic acid resin may decrease. . In addition, when the content of the epoxy-based monomer is less than the above range, it is difficult to secure the compatibility and transparency as described above, and on the contrary, when the content of the epoxy-based monomer exceeds the above range, the problem of lowering the impact strength occurs.

The shell containing this composition is used in an amount of 10 to 30% by weight within 100% by weight of the monomers constituting the total acrylic impact modifier. If the content of the shell is less than the above range, the compatibility with the polylactic acid resin may be deteriorated. Conversely, if the content of the shell exceeds the above range, the impact strength may decrease. Therefore, it is appropriately used within the above range.

Any acrylic impact modifier comprising the above-described composition may be used as long as it is a method capable of forming a core-shell structure.

Specifically, the acrylic impact modifier according to the present invention

Copolymerizing an alkyl acrylate monomer and a methyl methacrylate monomer to prepare a seed (S1);

Preparing an acrylic core by copolymerizing an alkyl acrylate and a polyalkylene glycol-based monomer in the seed (S2); And

It is prepared through a step (S3) of copolymerizing methyl methacrylate and an epoxy-based monomer on the acrylic core to prepare a shell.

It will be described in detail for each step below.

First, a seed is prepared by copolymerizing an alkyl acrylate monomer and a methyl methacrylate monomer (S1).

The preparation of the seed is not particularly limited in the present invention, and may be polymerized by applying various methods such as emulsion polymerization, block polymerization, suspension polymerization, solution polymerization, and preferably emulsion polymerization.

During emulsion polymerization, an initiator, an emulsifier, and an activator commonly known in the art, an oxidation-reduction catalyst, and an additive such as ion water may be further included in the monomer.

As the initiator, a water-soluble initiator may be used, and examples thereof include inorganic peroxides such as sodium persulfate, potassium persulfate, ammonium persulfate, potassium perphosphate, and hydrogen peroxide; t-butyl peroxide, cumene hydroperoxide, p-mentane hydroperoxide, di-t-butyl peroxide, t-butylcumyl peroxide, acetyl peroxide, isobutyl peroxide, octanoyl peroxide, dibenzoyl peroxide Organic peroxides such as oxide, 3,5,5-trimethylhexanol peroxide, and t-butyl peroxy isobutylate; And nitrogen compounds such as azobis isobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, and azobis isobutyric acid (butyric acid) methyl. These initiators are used in an amount of 0.03 to 0.2 parts by weight based on 100 parts by weight of the total monomer.

The emulsifier may be selected from the group consisting of an anionic emulsifier, a cationic emulsifier, and a nonionic emulsifier, and is not particularly limited in the present invention. For example, as an emulsifier, sulfonate, carboxylate, succinate, sulfosuccinate, and metal salts thereof, such as alkylbenzenesulfonic acid, sodium alkylbenzenesulfonate, alkylsulfonic acid, sodium alkylsulfonate, sodium poly Oxyethylene nonylphenyl ether sulfonate, sodium stearate, sodium dodecyl sulfate, sodium lauryl sulfate, sodium dodecyl sulfosuccinate, potassium oleate, anionic, widely used in emulsion polymerization, etc. Emulsifiers; Cationic emulsifiers to which an amine halide, an alkyl tetraammonium salt, an alkylpyridinium salt, and the like are bound as a functional group of a higher aliphatic hydrocarbon; One or more can be selected from the group consisting of nonionic emulsifiers such as polyvinyl alcohol and polyoxyethylene nonylphenyl, but is not limited to these emulsifiers. These emulsifiers may be used in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the monomer mixture.

The activating agent is not limited thereto, but at least one selected from sodium hydrosulfite, sodium formaldehyde sulfoxylate, sodium ethylenediamine tetraacetate, ferrous sulfate, lactose, dextrose, sodium rirolenate, and sodium sulfate. Each of them may be added within the range of 0.01 to 0.15 parts by weight based on a total of 100 parts by weight of the monomer. Preferably, a combination of sodium formaldehyde sulfoxylate, sodium ethylenediamine tetraacetate and ferrous sulfate is used as the activator.

The polymerization may be performed at 40 to 80° C. for 2 to 12 hours.

Next, an acrylic core is formed by copolymerizing an alkyl acrylate and a polyalkylene glycol-based monomer with the prepared seed (S2);

The polymerization reaction for preparing the acrylic core follows the description in the above-described emulsion polymerization. For example, it is preferable to add an initiator, an emulsifier, and various additives required for emulsion polymerization and carry out for 3 to 5 hours at a temperature of 40 to 80°C. At this time, various compositions and reaction conditions are not particularly limited in the present invention, and follow what is known in the art.

Next, the acrylic core obtained in (S2) is polymerized with methyl methacrylate and an epoxy monomer to form a shell (S3) to prepare an acrylic impact modifier having a core-shell structure (S3).

The polymerization reaction for the formation of the shell is as described in the above-described emulsion polymerization.

The acrylic impact modifier prepared through the above steps is agglomerated by adding 0.2 to 8 parts by weight of CaCl ₂ based on 100 parts by weight of latex at a temperature of 40 to 80°C, and then dried to prepare a powder state.

Polylactic acid resin composition

The acrylic impact modifier thus prepared has a refractive index in the range of 1.460 to 1.469, and thus has a refractive index almost the same as that of the polylactic acid resin having a refractive index of 1.46. Accordingly, when used as an impact modifier, a high level of transparency can be achieved due to the same level of refractive index as the polylactic acid resin, and the molded product of the finally manufactured polylactic acid resin has a haze of 3.5% or less.

In addition, the acrylic impact modifier according to the present invention has an average particle diameter of 180 to 260 nm, preferably 190 to 250 nm, and is used as an additive in the processing process of a polylactic acid resin to improve processability, and the manufactured molded article can secure high impact strength. I can.

Specifically, the polylactic acid resin composition according to the present invention is added in an amount of 0.1 to 30 parts by weight of an acrylic impact modifier based on 100 parts by weight of the polylactic acid resin to produce various molded articles through various molding processes. The content of the acrylic impact modifier is to improve the impact resistance and the surface condition of the finally obtained molded article, and if the content is less than the above range, it is not possible to expect improvement of the impact resistance, and if it exceeds the above range, the physical properties may be rather deteriorated. Therefore, it is appropriately adjusted within the above range.

At this time, if necessary, various additives commonly used in this field may be further included. The additives include processing aids, heat stabilizers, lubricants, plasticizers, UV stabilizers, flame retardants, coloring agents, fillers, flame retardants, antibacterial agents, release agents, antioxidants, compatibilizers, coloring agents, surfactants, nucleating agents, coupling agents, antistatic agents, flame retardants, etc. Conventional additives of may be added, and these may be applied alone or in combination of two or more.

Molding using the polylactic acid resin composition is not particularly limited in the present invention, and a known method is followed.

Hereinafter, a preferred embodiment is presented to aid the understanding of the present invention, but the following examples are only illustrative of the present invention, and it is obvious to those skilled in the art that various changes and modifications are possible within the scope and spirit of the present invention, It is natural that such modifications and modifications fall within the appended claims. The content presented below is based on solid content.

[Example]

Example 1: acrylic impact Reinforcement And Polylactic acid Preparation of resin composition

Preparation of acrylic impact modifier

(1) preparation of seeds

80 parts by weight of ion-exchanged water was put into a 3 L glass reactor, and sodium dodecyl sulfate (SLS, 3 wt% solution) 0.08 parts by weight, butyl acrylate (BA) 7.2 parts by weight, and methyl methacrylate (MMA) 0.8 Part by weight was added. In a nitrogen atmosphere, the internal temperature of the reactor was raised to 60°C, and 0.01 parts by weight of ethylenediamine tetrasodium acetate, 0.0005 parts by weight of ferrous sulfate, 0.05 parts by weight of sodium formaldehyde sulfoxylate, and 0.05 parts by weight of t-butyl hydroperoxide were added thereto. Reaction for a period of time to prepare a seed latex.

The prepared seed latex had a polymerization conversion rate of 97% and a particle size of 100 nm.

(2) Preparation of acrylic core

In order to form an acrylic rubber latex core in the seed latex prepared in (1) above, 40 parts by weight of ion water, 71.5 parts by weight of butyl acrylate (BA), polyethylene glycol in the reactor containing the seed latex prepared in (1) above. Monomer-free emulsion containing 0.5 parts by weight of diacrylate (PEGDA) methacrylate and 0.7 parts by weight of sodium dodecyl sulfate (SLS), 0.02 parts by weight of ethylenediamine tetrasodium acetate, 0.001 parts by weight of ferrous sulfate, sodium formaldehyde alcohol 0.1 parts by weight of foxylate and 0.1 parts by weight of t-butyl hydroxide were continuously added for 3 hours to proceed the reaction.

At this time, the temperature in the reactor was maintained at 60°C. After the addition was finished, it was aged at 60° C. for 1 hour to prepare an acrylic core.

(3) shell manufacturing

Cell monomer-free containing 25 parts by weight of ion-exchanged water, 15 parts by weight of methyl methacrylate, 5 parts by weight of glycidyl methacrylate, and 0.2 parts by weight of sodium dodecyl sulfate (SLS) in the acrylic core prepared in (2) above. The emulsion and ethylenediamine tetrasodium acetate 0.006 parts by weight, ferrous sulfate 0.0003 parts by weight, sodium formaldehyde sulfoxylate 0.03 parts by weight and t-butyl hydroperoxide 0.03 parts by weight were continuously added for 2 hours to proceed the reaction.

At this time, the reactor temperature was maintained at 70 ℃. After the addition was finished, it was aged at 70° C. for 1 hour to prepare an acrylic latex. The polymerization conversion rate of the prepared acrylic latex was 95%, and the particle size was 230 nm.

In the prepared core-shell structured acrylic graft copolymer, 4 parts by weight of CaCl ₂ was added as a coagulant to solidify, the polymer and water were separated, and then dehydrated and dried to obtain a graft copolymer powder having an average particle diameter of 200 μm.

Preparation of polylactic acid resin composition

100 parts by weight of the polylactic acid resin was melt-mixed for 10 minutes at 190 and 30 rpm using a Haake Rheomix 600 batch mixer, 10 parts by weight of an MBS-based impact modifier, 0.5 parts by weight of a polymer lubricant, and 0.2 parts by weight of a heat stabilizer. The melt-mixed resin prepared with a Haake Rheomix mixer was compression molded at 200° C., 10 minutes, and 0.20 MPa to prepare a 3.2 mm thick specimen.

Example 2: acrylic impact Reinforcement And Polylactic acid Preparation of resin composition

In the same manner as in Example 1, except that 12 parts by weight of metal methacrylate (MMA) and 8 parts by weight of glycidyl methacrylate (GMA) were used when manufacturing the shell, acrylic impact modifier powder and polylactic acid resin sheet were prepared. Was produced.

Example 3: Preparation of acrylic impact modifier and polylactic acid resin composition

In the same manner as in Example 1, except that 18 parts by weight of metal methacrylate (MMA) and 2 parts by weight of glycidyl methacrylate (GMA) were used when manufacturing the shell, an acrylic impact modifier powder and a polylactic acid resin sheet were prepared. Was produced.

Comparative Example 1: Preparation of polylactic acid resin composition

A sheet was produced using a polylactic acid resin alone without using an impact modifier.

Comparative Example 2: Preparation of acrylic impact modifier and polylactic acid resin composition

In the same manner as in Example 1, except that 20 parts by weight of metal methacrylate (MMA) was used alone when manufacturing the shell, acrylic impact modifier powder and polylactic acid resin sheet were prepared.

Comparative Example 3: Preparation of acrylic impact modifier and polylactic acid resin composition

In the same manner as in Example 1, except that 8 parts by weight of metal methacrylate (MMA) and 12 parts by weight of glycidyl methacrylate (GMA) were used when manufacturing the shell, acrylic impact modifier powder and polylactic acid resin sheet were prepared. Was produced.

Comparative Example 4: Preparation of acrylic impact modifier and polylactic acid resin composition

When preparing seeds, 4.5 parts by weight of butyl acrylate (BA) and 0.5 parts by weight of methyl methacrylate (MMA) were used, and when preparing the shell, 15 parts by weight of methyl methacrylate (MMA) and glycidyl methacrylate (GMA) An acrylic impact modifier powder and a polylactic acid resin sheet were prepared in the same manner as in Example 1, except that 5 parts by weight were used.

Comparative Example 5: Preparation of acrylic impact modifier and polylactic acid resin composition

When preparing seeds, 18 parts by weight of butyl acrylate (BA) and 2 parts by weight of methyl methacrylate (MMA) were used, and 59.5 parts by weight of butyl acrylate (BA) and 0.5 parts by weight of polyethylene glycol diacrylate were used when preparing the core. , Acrylic impact modifier powder and polylactic acid resin sheet were carried out in the same manner as in Example 1, except that 15 parts by weight of methyl methacrylate (MMA) and 5 parts by weight of glycidyl methacrylate (GMA) were used when manufacturing the shell. Was produced.

Comparative Example 6: Preparation of acrylic impact modifier and polylactic acid resin composition

Except for using 72 parts by weight of butyl acrylate (BA) alone when manufacturing the core, and using 15 parts by weight of methyl methacrylate (MMA) and 5 parts by weight of glycidyl methacrylate (GMA) when manufacturing the shell. In the same manner as in Example 1, an acrylic impact modifier powder and a polylactic acid resin sheet were prepared.

Comparative Example 7: Preparation of MBS-based impact modifier and polylactic acid resin composition

A polylactic acid resin sheet was prepared using an MBS-based impact modifier (butadiene-methylmethacrylate-styrene, manufactured in KR Patent Publication 10-2015-0037648 Example 1).

The content of the monomers constituting the acrylic impact modifier powder prepared in Examples and Comparative Examples, average particle diameter, and refractive index are summarized in Table 1 below. At this time, the refractive index was calculated through the following equation.

Refractive index (R.I.) = [(MMA content x 1.489) + (BA content x 1.466) + (PEGDA content x 1.506) + (GMA content x 1.381)] / 100

(Referring index value: PLA: 1.46, PMMA: 1.489, PBA: 1.466, PEGDA: 1.506, PGMA: 1.381)

Composition (% by weight) Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Impact modifier Seed BA 7.2 7.2 7.2 - 7.2 7.2 4.5 18 7.2 MBS series MMA 0.8 0.8 0.8 - 0.8 0.8 0.5 2 0.8 core BA 71.5 71.5 71.5 - 71.5 71.5 74.5 59.5 72 PEGDA 0.5 0.5 0.5 - 0.5 0.5 0.5 0.5 Shell MMA 15 12 18 - 20 8 15 15 15 GMA 5 8 2 - 12 5 5 5 Average particle diameter (nm) 230 232 226 - 229 234 271 170 235 200 Refractive index 1.465 1.462 1.469 - 1.471 1.458 1.465 1.466 1.465 1.51 Polylactic acid resin composition Polylactic acid (% by weight) 90 90 90 100 90 90 90 90 90 90 Impact modifier (% by weight) 10 10 10 - 10 10 10 10 10 10

Experimental Example 1: Measurement and analysis of physical properties

The physical properties of the polylactic acid resin obtained in Examples and Comparative Examples were evaluated as follows, and the results are shown in Table 2 below.

-Izod impact strength (kgf·cm/cm): The impact strength of each polylactic acid resin specimen of Examples and Comparative Examples was measured according to ASTM D256.

-Falling impact strength

dart impact strength, J): It was measured according to the ASTM D5420 test method.

-Haze (%): It was measured according to ASTM D1003 using a haze meter, and at this time, the lower the value, the higher the transparency.

Impact strength (kgf·cm/cm) Falling ball impact strength (J) Haze (%) Example 1 23.4 56 2.9 Example 2 24.6 56 2.5 Example 3 22.5 54 3.4 Comparative Example 1 2.8 11 1.2 Comparative Example 2 20.1 51 3.8 Comparative Example 3 18.8 47 2.3 Comparative Example 4 27.1 59 4.4 Comparative Example 5 17.2 45 2.0 Comparative Example 6 18.3 43 2.8 Comparative Example 7 22.60 53 46.2

Referring to Table 2, compared to the resin of Comparative Example 1 in which the impact modifier was not used, the resins of the examples and other comparative examples including the impact modifier have significantly improved impact strength. However, the transparency tended to decrease by the use of the impact modifier.

In the case of the resin of Comparative Example 2, due to the non-use of glycidyl methacrylate in the shell, it was found that the refractive index slightly increased and the transparency was lowered. As the result was lowered, the transparency was improved, but the impact strength decreased.

In addition, looking at the results of Comparative Examples 4 to 5, when the content of the seed is too small or too large, it affects the final particle size size and affects the impact strength and transparency, and as in Comparative Example 6, a water-soluble comonomer as a core composition It can be seen that the impact strength is lowered when the polyalkylene glycol-based monomer is not used.

In addition, in the case of using an MBS-based impact modifier other than acrylic, it was confirmed that both the Izod and the falling ball impact strength were improved, but the transparency was severely deteriorated from the results of Comparative Example 7.

From these results, it can be seen that in the case of the impact modifier used for the polylactic acid resin, the transparency and impact strength characteristics can be simultaneously satisfied only when the acrylic impact modifier presented in the present invention is used.

The acrylic impact modifier according to the present invention can be used as an additive in the polylactic acid resin composition to produce a molded article having excellent transparency and impact resistance.

Claims (9)

Based on 100% by weight of the total of the monomers constituting the acrylic impact modifier
6.5 to 15% by weight of a seed polymerized with an alkyl acrylate monomer;
63.5 to 75% by weight of an acrylic core copolymerized with an alkyl acrylate monomer and a polyalkylene glycol monomer on the seed; And
It surrounds the acrylic core and contains 10 to 30% by weight of a shell in which methyl methacrylate and an epoxy monomer are copolymerized,
The alkyl acrylate monomer in the seed and core is at least one selected from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate and stearyl acrylate,
In the shell, the epoxy monomer is at least one selected from the group consisting of glycidyl methacrylate, triglycidyl isocyanurate, bis(4-epoxycyclohexylmethyl) adipate and cyclooctadiene diepoxide. As a reinforcing agent,
Acrylic impact modifier, characterized in that the refractive index is 1.460 to 1.469, the average particle diameter is 180 to 260nm. The method of claim 1,
In addition, the seed is an acrylic impact modifier, characterized in that the copolymer further comprises 1.5% by weight or less of methyl methacrylate based on the total 100% by weight of the monomers constituting the acrylic impact modifier. The method of claim 1,
The core is an acrylic impact modifier, characterized in that 63.4 to 74% by weight of alkyl acrylate and 0.1 to 1% by weight of polyalkylene glycol-based monomer are polymerized based on 100% by weight of the total monomers constituting the acrylic impact modifier. According to claim 1
The shell is an acrylic impact modifier, wherein 9 to 20% by weight of methyl methacrylate and 1 to 10% by weight of an epoxy monomer are polymerized with respect to 100% by weight of the total monomers constituting the acrylic impact modifier. delete The method of claim 1,
The polyalkylene glycol-based monomers are poly(ethylene glycol) monoacrylate, poly(ethylene glycol) monomethacrylate, poly(propylene glycol) monoacrylate, poly(propylene glycol) monomethacrylate, poly(ethylene glycol) ) Diacrylate, poly(ethylene glycol) dimethacrylate, poly(propylene glycol) diacrylate, poly(propylene glycol) dimethacrylate, methoxy poly(ethylene glycol) monoacrylate, methoxy(ethylene glycol) ) Monomethacrylate, methoxy poly(propylene glycol) monoacrylate, methoxypoly(propylene glycol) monomethacrylate, phenoxy poly(ethylene glycol) monoacrylate, phenoxy poly(ethylene glycol) monomethacryl Rate, an acrylic impact modifier, characterized in that at least one selected from the group consisting of phenoxy poly (ethylene propylene) monoacrylate and phenoxy poly (ethylene propylene) monomethacrylate. delete delete A polylactic acid resin composition comprising the acrylic impact modifier according to any one of claims 1 to 4 and 6.