KR102043264B1 - Polylactic acid resin film - Google Patents

Abstract

The present invention not only exhibits improved flexibility and moisture resistance, but also has excellent physical properties such as mechanical properties, transparency, heat resistance, blocking resistance, and film processability, and thus can be usefully used as a packaging material. It is about a film.
The polylactic acid resin film is a polylactic acid resin film including a polylactic acid resin and an antioxidant, and a hard segment including a polylactic acid repeating unit of Formula 1, and a polyolefin-based polyol structural unit of Formula 2 may be a urethane bond or an ester bond. A polylactic acid resin having a soft segment including a polyolefin-based polyol repeating unit connected linearly or branched by a medium and having an organic carbon content (% C _bio ) of at least 60% by weight as defined by Equation 1 ; And antioxidants.

Description

Polylactic acid resin film {POLYLACTIC ACID RESIN FILM}

The present invention relates to a polylactic acid resin film and a packaging film including the same. More specifically, the present invention not only exhibits improved flexibility, but also has excellent physical properties such as moisture resistance, mechanical properties, transparency, heat resistance, blocking resistance, and film processability, and thus may be usefully used as a packaging material. The present invention relates to a polylactic acid resin film containing a polylactic acid resin having an antioxidant and an antioxidant.

Crude oil-based resins such as polyethylene terephthalate, nylon, polyolefin, or soft polyvinyl chloride (PVC) are still widely used as materials for various applications such as packaging materials. However, such crude oil-based resins do not have biodegradability, and thus, there is a problem of causing environmental pollution such as discharging a large amount of carbon dioxide, which is a global warming gas, at the time of disposal. In addition, as the petroleum resources are gradually exhausted, in recent years, the use of biomass-based resins, typically polylactic acid resins, has been widely studied.

However, since the polylactic acid resin does not have sufficient heat resistance, moisture resistance, or mechanical properties, compared to crude oil-based resins, it is true that the polylactic acid resin has a limited field or application to which it can be applied. In particular, attempts have been made to apply polylactic acid resin as a packaging material such as a packaging film, but such applications are facing limitations due to the low flexibility of the polylactic acid resin.

In order to overcome the limitations of the polylactic acid resin, a method of adding a low molecular weight softener or a plasticizer to the polylactic acid resin or introducing a plasticizer obtained by addition-polymerizing a polyether-based or aliphatic polyester-based polyol to the polylactic acid resin is proposed. It has been.

However, even if a packaging film or the like containing polylactic acid resin is obtained by these methods, it is true that in most cases, there is a limit to improving the flexibility. In addition, the plasticizer and the like not only bleed out over time, but also had disadvantages in that the haze of the packaging film was increased and transparency was lowered.

In addition, recently, in order to solve the above problems, a method of obtaining a block copolymer by introducing a polyurethane polyol repeating unit into a polylactic acid resin has been proposed (Korean Patent Publication Nos. 1119966, 1191967, 1191968 and No. 1). 1191961, and Republic of Korea Patent Publication Nos. 2012-0068552, 2012-0068550, 2012-0094552, 2012-0086118 and 2012-0086117).

On the other hand, a polylactic acid copolymer comprising a soft segment in which a polyester polyol repeating unit is connected by a urethane bond or a resin composition or film including the same has been known. However, such a polylactic acid copolymer has low transparency and high haze value due to low compatibility of polyester polyol and polylactic acid, and high moisture content of polyester polyol and polylactic acid. There was a problem. In addition, such a polylactic acid copolymer has a wide molecular weight distribution and poor melting characteristics, so that the film extrusion state is not good, and the mechanical properties, heat resistance, and blocking resistance of the film are also insufficient.

As mentioned above, polylactic acid resins are generally very poor in moisture resistance, which is mainly caused by the hydrolysis reaction by water contained in the resin, and as a result, part of the polymer is decomposed into lactic acid, monomer or oligomer. And molecular weight fall occurs.

Furthermore, the resulting lactic acid, monomers and oligomers may volatilize during the molding process of the resin, causing contamination and corrosion of the machinery, and also causing quality problems of the molded product. Specifically, in the case of sheet manufacturing by extrusion molding, lactic acid, monomers and oligomers remaining in the resin may volatilize when the sheet is extruded, resulting in a thickness variation of the manufactured sheet. Hydrolysis may occur and deterioration of mechanical properties may occur.

Therefore, the development of a packaging film containing a polylactic acid resin exhibiting improved flexibility and excellent moisture resistance and excellent physical properties such as mechanical properties, transparency, heat resistance, blocking resistance, or bleed-out characteristics, It is constantly demanded.

Republic of Korea Patent No. 1191966 (Eske Chemical Co., Ltd.) 2012.10.17. Republic of Korea Patent Publication No. 1191967 (Eske Chemical Co., Ltd.) 2012.10.17. Republic of Korea Patent Publication No. 1191968 (Eske Chemical Co., Ltd.) 2012.10.17. Republic of Korea Patent Publication No. 1111961 (Eske Chemical Co., Ltd.) 2012.10.17. Republic of Korea Patent Application Publication No. 2012-0068552 (Eske Chemical Co., Ltd.) 2012.06.27. Republic of Korea Patent Application Publication No. 2012-0068550 (Eske Chemical Co., Ltd.) 2012.06.27. Republic of Korea Patent Publication No. 2012-0094552 (Eske Chemical Co., Ltd.) 2012.08.27. Republic of Korea Patent Publication No. 2012-0086118 (Eske Chemical Co., Ltd.) 2012.08.02. Republic of Korea Patent Application Publication No. 2012-0086117 (Eske Chemical Co., Ltd.) 2012.08.02.

The present invention not only exhibits improved flexibility, but also has excellent physical properties such as moisture resistance, mechanical properties, transparency, heat resistance, blocking resistance, and film processability, and thus can be usefully used as a packaging material. To provide a film.

In accordance with the above object, the present invention provides a hard segment including a polylactic acid repeating unit of Formula 1, and a polyolefin in which polyolefin-based polyol structural units of Formula 2 are linearly or branched through a urethane bond or an ester bond. A polylactic acid resin containing a soft segment including a repeating unit of a polyol, wherein an organic carbon content rate (% C _bio ) of a biomass origin defined by Equation 1 below is 60% by weight or more; And a polylactic acid resin film comprising an antioxidant:

[Formula 1]

[Formula 2]

[Equation 1]

% C = _Bio (poly ¹⁴ C isotope ratio by weight of the ¹² C isotope of carbon atoms of the lactic acid resin) / ⁽¹⁴ C isotope ratio by weight of the ^bio-12 C isotope of carbon atoms of the mass origin standard)

In Chemical Formulas 1 and 2, n is an integer of 700 to 5,000, m + 1 is an integer of 5 to 200.

The polylactic acid resin film according to the present invention, while exhibiting the eco-friendly properties and biodegradability peculiar to polylactic acid resin, has optimized flexibility, moisture resistance and stiffness, excellent mechanical properties, heat resistance, transparency, blocking resistance and film Since it contains a polylactic acid film exhibiting processability and the like, it can replace the packaging film obtained from the crude oil-based resin when used as a packaging material such as a packaging film, and can greatly contribute to preventing environmental pollution.

Hereinafter, a polylactic acid resin film and a polylactic acid resin and an antioxidant included in the polylactic acid resin film will be described.

In the polylactic acid resin film according to the present invention, a hard segment including a polylactic acid repeating unit of Formula 1 and a polyolefin-based polyol structural unit of Formula 2 may be linearly or branched through a urethane bond or an ester bond. And a soft segment comprising a polyolefin-based polyol repeating unit, wherein the polylactic acid resin having an organic carbon content (% C _bio ) of biomass origin defined by Equation 1 below 60 wt% or more, and an antioxidant .

[Formula 1]

[Formula 2]

[Equation 1]

% C = _Bio (poly ¹⁴ C isotope ratio by weight of the ¹² C isotope of carbon atoms of the lactic acid resin) / ⁽¹⁴ C isotope ratio by weight of the ^bio-12 C isotope of carbon atoms of the mass origin standard)

In Chemical Formulas 1 and 2, n is an integer of 700 to 5,000, m + 1 is an integer of 5 to 200.

The polylactic acid resin film includes a predetermined polylactic acid resin and an antioxidant, and the polylactic acid resin basically includes a polylactic acid repeating unit represented by Chemical Formula 1 as a hard segment. In addition, the polylactic acid resin includes a polyolefin-based polyol repeating unit as a soft segment, wherein the polyolefin-based polyol repeating unit is a polyolefin-based polyol structural unit represented by the formula (2) is a urethane bond (-C (= O) -NH- ) Or a linear or branched structure via an ester bond (-C (= O) -O-).

Such polylactic acid resins may exhibit biodegradable and eco-friendly characteristics peculiar to biomass-based resins by including polylactic acid repeating units as hard segments. In addition, as a result of the experiments of the present inventors, the polyolefin-based polyol repeating unit is included as a soft segment, so that the polylactic acid resin has a significantly improved flexibility (for example, a relatively low Young's modulus when measured in the length and width directions). It has been found that a film can be produced that exhibits excellent transparency and low haze values, as well as a). In particular, as the soft segment is introduced into the polylactic acid resin itself in a form combined with the hard segment, the soft segment for improved flexibility is less likely to bleed out or exhibit low stability, such as a film including the polylactic acid resin. It was also confirmed that there is a fear that the haze will increase or the transparency will decrease. In addition, the polylactic acid resin may exhibit the above-described effects without significantly increasing the content of the soft segment for improving flexibility, so that the hard segment derived from a relatively high content of biomass-based resin such as polylactic acid resin may be used. It may include.

On the other hand, since the polylactic acid resin contains a non-polar soft segment, it has excellent moisture resistance compared to ordinary polylactic acid resin.

The polylactic acid resin has an organic carbon content (% C _bio ) of biomass origin defined by Equation 1 of about 60% by weight or more, about 70% by weight, about 80% by weight, about 85% by weight, Or at least about 90 weight percent, or at least about 95 weight percent.

In contrast, in the case of including polyester repeating units other than polyolefin repeating units as soft segments, other resins such as polyester polyol repeating units of higher fossil fuel origin may be introduced to achieve excellent flexibility. As needed, it may be difficult to achieve the above described organic carbon content of about 60% by weight (% C _bio ).

The method for measuring the organic carbon content rate (% C _bio ) of biomass origin according to Equation 1 may be, for example, according to the method described in ASTM D6866 standard. The technical meaning and measurement method of the organic carbon content (% C _bio ) will be described in more detail as follows.

In general, unlike organic materials such as resins derived from fossil raw materials, organic materials such as resins derived from biomass (biological resources) are known to contain isotopes ^14C . More specifically, all organic materials taken from living organisms, such as animals or plants, are ¹² C (about 98.892 weight percent), ¹³ C (about 1.108 weight percent) and ¹⁴ C (about 1.2 × 10 ^-10 weight percent) as carbon atoms. It is known to contain three isotopes, and the ratio of each isotope is known to remain constant. This is equal to the ratio of each isotope in the atmosphere, and this isotope ratio remains constant because living organisms continue to exchange carbon atoms with the external environment as they continue their metabolism.

)의 경과에 따라 그 함량이 감소할 수 있다. On the other hand, ¹⁴ C is a radioactive isotope according to the following equation (2)

The content may decrease with age.

[Equation 2]

는 ¹⁴C 동위원소의 초기 원자수를 나타내고, 상기

은

시간 후에 잔존하는 ¹⁴C 동위원소의 원자수를 나타내며, 상기

는 반감기와 관련된 붕괴 상수(또는 방사성 상수)를 나타낸다.
In Equation 2,

Represents the initial number of atoms of the ¹⁴ C isotope, and

silver

Represents the number of atoms of ¹⁴ C isotope remaining after time;

Represents the decay constant (or radioactive constant) associated with the half-life.

In Equation 2, the half-life of the ¹⁴ C isotope is about 5,730 years. Considering these half-life, the environment and continuously to each other organic material such as a resin derived from the organic material, i.e. biomass (biological resources), taken from a living organism acting despite fine content reduction of the isotope, and a substantially constant ¹⁴ It is possible to maintain a constant content ratio (weight ratio) of C isotope content and a constant content ratio with other isotopes, such as ¹⁴ C / ¹² C = about 1.2 × 10 ^-12 .

In comparison, fossil fuels such as coal or petroleum have been blocked from exchanging carbon atoms with the outside environment for more than 50,000 years. Accordingly, the organic material such as the resin derived from the fossil raw material contains ¹⁴ C isotope at 0.2% or less of the initial content (atomic number) when estimated according to Equation 2, and substantially contains ¹⁴ C isotope. I never do that.

Equation 1 considering the above-described points, the denominator may be a weight ratio of ¹⁴ C / ¹² C isotope derived from biomass, such as about 1.2 × 10 ^-12 , the molecule is ¹⁴ C contained in the resin to be measured It may be a weight ratio of / ¹² C. As mentioned above, carbon atoms derived from biomass maintain an isotope weight ratio of about 1.2 × 10 ⁻¹² , whereas carbon atoms derived from fossil fuel have a substantially zero such isotope weight ratio. In the polylactic acid resin, the organic carbon content rate (% C _bio ) of biomass origin among all carbon atoms can be measured by Equation 1 above. In this case, the content of each carbon isotope and the content ratio (weight ratio) thereof are described in the ASTM D6866-06 standard (a standard test method for determining the biobased content of natural substances using radiocarbon and isotope ratio mass spectrometry analysis). It can be measured according to one of three methods. Suitably, the carbon atoms contained in the resin to be measured may be in the form of graphite or carbon dioxide gas and measured by mass spectrometry or by liquid scintillation spectroscopy. In this case, two isotopes may be separated together with an accelerator for separating ¹⁴ C ions from ¹² C ions together with the mass spectrometer, and the content and content ratio of each isotope may be measured by a mass spectrometer. Alternatively, the content and content ratio of each isotope may be obtained by using liquid scintillation spectroscopy that is obvious to those skilled in the art, through which the measurement value of Equation 1 may be derived.

When the measured value of the organic carbon content (% C _bio ) of Equation 1 thus obtained is about 60% by weight or more, the polylactic acid resin and the polylactic acid resin film including the same include a resin derived from a higher content of biomass and It contains carbon and can exhibit the unique environmentally friendly characteristics and biodegradability suitably.

More specifically, the polylactic acid resin satisfying such a high organic carbon content (% C _bio ) and the polylactic acid resin film including the same may exhibit environmentally friendly characteristics described below.

Biochemical products such as polylactic acid resins are biodegradable, with low carbon dioxide emissions, up to 108% less carbon dioxide emissions than current petrochemical products, and up to 50% energy savings for resin production. can do. In addition, the production of bioplastics using biomass feedstocks can reduce carbon dioxide emissions calculated by ISO 14000 compliant Life Cycle Analysis (LCA) by up to 70% compared to fossil feedstock use.

As a specific example, according to NatureWorks, the production of PET resin produces 3.4 kg of carbon dioxide per kg, whereas polylactic acid resin, a kind of bioplastic, generates only about 0.77 kg of carbon dioxide per kg. It is known to reduce carbon dioxide and is only 56% of the energy consumption. However, in the case of the polylactic acid resin previously known, there was a limitation in application due to low flexibility, and when including other components such as a plasticizer to solve this problem, there was a problem in that the advantages as the bioplastic mentioned above were greatly reduced.

However, as the polylactic acid resin satisfies the above-described high organic carbon content (% C _bio ), the polylactic acid resin can be applied to more various fields by solving the problems such as low flexibility of the polylactic acid resin while fully utilizing its advantages as a bioplastic. have.

Therefore, the polylactic acid resin and the polylactic acid resin film including the same satisfying the high organic carbon content (% C _bio ) described above may exhibit environmentally friendly characteristics that greatly reduce carbon dioxide generation and energy usage by utilizing the advantages as bioplastics. Such environmentally friendly properties can be measured, for example, through life cycle assessment of polylactic acid resins.

The polylactic acid resin has a content of ¹⁴ C isotopes in carbon atoms of about 7.2 × 10 ⁻¹¹ to 1.2 × 10 ⁻¹⁰ wt%, about 9.6 × 10 ⁻¹¹ to 1.2 × 10 ⁻¹⁰ wt%, or about 1.08 × 10 ^It may be ^-10 to 1.2 × 10 ^-10 wt%. Polylactic acid resins having such ¹⁴ C isotope content may have more resin and carbon, or substantially all of the resin and carbon derived from the biomass, and may exhibit better biodegradability and environmentally friendly properties.

In the polylactic acid resin, not only the polylactic acid repeating unit of the hard segment is derived from biomass, but the polyolefin-based polyol structural unit of the soft segment may also be derived from biomass. Such polyolefin-based polyol structural units can be obtained, for example, from polyolefin-based polyol resins derived from biomass. The biomass can be any plant or animal resource, for example a plant resource such as corn, sugar cane, or tapioca. As such, the polylactic acid resin comprising a polyolefin-based polyol structural unit derived from biomass has a higher organic carbon content (% C _bio ), such as about 90% by weight or more, or about 95% by weight or more of organic carbon content (% C _Bio ).

In this case, in the polylactic acid resin, the hard segment derived from the biomass has an organic carbon content rate (% C _bio ) of biomass origin defined by Equation 1 above about 90 wt% or more, preferably about 95 to 100 The soft segment derived from the biomass may have an organic carbon content (% C _bio ) of biomass origin defined by Equation 1 above about 70% by weight, preferably about 75 to 95% by weight. Can be.

The polylactic acid resin has a high organic carbon content (% C _bio ) of biomass origin of at least about 60% by weight, or at least about 80% by weight, and is therefore certified by JBPA's "Biomass" based on standard ASTM D6866. Pla) "can be met to achieve the criteria. Thus, the polylactic acid resin can legitimately attach JORA's "Biomass-based" label.

In the polylactic acid resin, the polylactic acid repeating unit of Formula 1 included in the hard segment may refer to a polylactic acid homopolymer or a repeating unit forming the same. Such polylactic acid repeating units can be obtained according to methods for preparing polylactic acid homopolymers well known to those skilled in the art. For example, L-lactide or D-lactide, which is a cyclic 2 monomer, is obtained from L-lactic acid or D-lactic acid, and is obtained by ring-opening polymerization, or by direct dehydration polycondensation of L-lactic acid or D-lactic acid. Among them, polylactic acid repeating units having a higher degree of polymerization can be obtained through the ring-opening polymerization method, which is preferable. In addition, the polylactic acid repeating unit may be prepared to have amorphous by copolymerizing L-lactide and D-lactide in a predetermined ratio, in order to further improve the heat resistance of the film containing the polylactic acid resin, It is preferred to prepare by the method of homopolymerization using either L-lactide or D-lactide. More specifically, the polylactic acid repeating unit can be obtained by ring-opening polymerization using L-lactide or D-lactide raw material with an optical purity of 98% or higher, and if the optical purity is not this, the melting temperature (Tm) of the polylactic acid resin Can be lowered.

Meanwhile, the polyolefin-based polyol repeating unit included in the soft segment of the polylactic acid resin may include a urethane bond (-C (= O) -NH-) or an ester bond (-C (= O). ) -O-) may have a structure connected in a linear or branched form, specifically, the polyolefin-based polyol structural unit is a polymer obtained by conjugate polymerization of a monomer such as butadiene (poly 1,2-butadiene or poly 1,3-butadiene) or a structural unit constituting the same refers to a liquid polybutadiene (HTPB) having a molecular weight of 1,000 to 5,000 obtained by applying a hydroxyl group to a terminal thereof and obtained through a hydrogenation reaction.

In this case, the urethane bond may be formed by reaction of a prepolymer obtained by addition polymerization of a lactide with a hydroxyl group at the terminal of the polyolefin-based polyol structural unit or a hydroxyl group at the terminal of the polyolefin-based polyol structural unit, and a diisocyanate or a bifunctional or more isocyanate compound. On the other hand, when the hydroxyl group at the end of the polyolefin-based polyol structural unit reacts with the lactide or lactic acid derivative compound it may form an ester bond (-C (= O) -O-). The polyolefin-based polyol structural units may be linearly or branched to each other to form the polyolefin-based polyol repeating unit through the urethane bond or the ester bond.

The reaction molar ratio of the hydroxy group at the terminal of the polyolefin-based polyol structural unit and the isocyanate group of the isocyanate compound of the diisocyanate or the bifunctional or more isocyanate compound may be 1: 0.50 to 1: 0.99. Preferably, the reaction molar ratio of the terminal hydroxyl group: isocyanate group of the isocyanate compound of the polyolefin-based polyol structural unit may be about 1: 0.60 to about 1: 0.95, more preferably about 1: 0.70 to about 1: 0.90.

The polymer or repeating units forming the polyolefin-based polyol structural units are linearly connected through a urethane bond, in particular, may be referred to as a polyurethane polyol repeating unit, and may have a hydroxyl group at the terminal thereof. Accordingly, the polyolefin-based polyol repeating unit may act as an initiator in the polymerization process for forming the polylactic acid repeating unit. However, when the reaction molar ratio of the hydroxy group: isocyanate group is excessively higher than 0.99, the number of terminal hydroxyl groups of the polyolefin-based polyol repeating unit may be insufficient (OHV <1), and thus may not function properly as an initiator. In addition, when the reaction molar ratio of the hydroxyl group: isocyanate group is too low, the number of terminal hydroxyl groups of the polyolefin-based polyol repeating unit is too large (OHV> 35), making it difficult to obtain a polylactic acid repeating unit having a high molecular weight and a polylactic acid resin.

The polymer of the polyolefin-based polyol repeating unit may have a number average molecular weight of about 1,000 to 100,000, preferably about 10,000 to 50,000. If the molecular weight of the polymer of the polyolefin-based polyol repeating unit is too large or small, flexibility, moisture resistance or mechanical properties of the polylactic acid resin and the film including the same may not be sufficient. In addition, since the polylactic acid resin may be difficult to meet the appropriate molecular weight characteristics, the processability of the resin or the flexibility, moisture resistance or mechanical properties of the film may be lowered.

The isocyanate compound capable of forming a urethane bond by bonding to the terminal hydroxyl group of the polyolefin-based polyol repeating unit may be any compound having two or more isocyanate groups in a molecule, and may be derived from a fossil fuel.

Examples of the diisocyanate compound include 1,6-hexamethylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,3-xylene diisocyanate, 1,4-xylene diisocyanate, 1 , 5-naphthalenedi isocyanate, m-phenylenedi isocyanate, p-phenylenedi isocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 4,4'-bisphenylenedi isocyanate, hexamethylene di Isocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, etc. are mentioned, As a polyvalent isocyanate compound whose equivalent of the said isocyanate group is three or more, the oligomer of the said diisocyanate compound, the polymer of the said diisocyanate compound, the said diisocyanate compound Cyclic multimer, hexamethylene diisocyanate isocyanurate (hexamethylene diisocyanate isocyanurate), triisocyanate compounds, and isocyanate compounds selected from the group consisting of these isomers. In addition, various diisocyanate compounds well known to those skilled in the art may be used without particular limitation. However, 1,6-hexamethylene diisocyanate is preferable from the viewpoint of flexibility to the polylactic acid resin film.

On the other hand, the polylactic acid resin, a block copolymer, or the block copolymer in which the terminal carboxyl group of the polylactic acid repeating unit included in the hard segment is connected by an ester bond with the terminal hydroxyl group of the polyolefin-based polyol structural unit included in the soft segment May comprise a block copolymer linked linearly or branched via a urethane bond.

Specifically, in such a block copolymer, the terminal carboxyl group of the polylactic acid repeating unit may form an ester bond with the terminal hydroxyl group of the polyolefinic polyol repeating unit. For example, the chemical structure of such block copolymers can be represented by the following general formula (1):

[Formula 1]

Polylactic Acid Repeating Unit (L)-(E) -Polyolefin Polyol Repeating Unit (O-U-O-U-O)-(E) -Polylactic Acid Repeating Unit (L)

[Formula 2]

Polylactic Acid Repeating Unit (L)-(E) -Polyolefin Polyol Constituent Unit (O)-(E) -Polylactic Acid Repeating Unit (L)-(U) -Polylactic Acid Repeating Unit (L)-(E) -Polyolefin Polyol structural unit (O)-(E) -polylactic acid repeating unit (L)

In Formulas 1 and 2, O represents a polyolefin-based polyol structural unit, U represents a urethane bond, and E represents an ester bond.

By including a block copolymer in which the polylactic acid repeating unit and the polyolefin-based polyol structural unit or the repeating unit are combined, the bleed-out of the polyolefin-based polyol structural unit or the repeating unit for providing flexibility may be suppressed. The polylactic acid resin film including the polylactic acid resin may have various physical properties such as excellent moisture resistance, transparency, mechanical properties, heat resistance, or blocking resistance. Further, as at least a portion of the polylactic acid structural unit or the repeating unit and the polyolefin-based polyol repeating unit take the form of a block copolymer, the molecular weight distribution, glass transition temperature (Tg), melting temperature (Tm), etc. of the polylactic acid resin This optimization can further improve the mechanical properties, flexibility and heat resistance of the film.

However, all of the polylactic acid repeating units included in the polylactic acid resin need not be in the form of the polyolefin-based polyol structural unit or the block copolymer combined with the repeating unit, and at least some of the polylactic acid repeating units are the polyolefin-based It may also be in the form of a polylactic acid homopolymer which is not combined with polyol structural units or repeating units. In this case, the polylactic acid resin is a block copolymer in which the terminal carboxyl group of the polylactic acid repeating unit included in the hard segment is connected by an ester bond to the terminal hydroxyl group of the polyolefin-based polyol structural unit included in the soft segment, or the block copolymer May be in the form of a mixture further comprising a polylactic acid repeating unit, that is, a polylactic acid homopolymer, which is not bonded to the polyolefin-based polyol repeating unit in a block copolymer connected linearly or branched through a urethane bond.

On the other hand, the polylactic acid resin is based on the total 100 parts by weight of the above (when the weight of the block copolymer described above, and optionally a polylactic acid homopolymer is included, 100 parts by weight in total with such a single polymer), as described above Hard segments about 65 to 95 parts by weight, about 80 to 95 parts by weight, or about 82 to 92 parts by weight, and about 5 to 35 parts by weight, about 5 to 20 parts by weight, or about 8 to 18 parts by weight of the soft segment. Can be.

When the content of the soft segment is too high, it may be difficult to provide a high molecular weight polylactic acid resin, which may lower mechanical properties such as strength of the film including the same. In addition, the glass transition temperature may be lowered, so that slipping, handling, or shape retention characteristics may be deteriorated in the packaging process using the film. On the contrary, if the content of the soft segment is too low, there is a limit in improving the flexibility and moisture resistance of the polylactic acid resin and the polylactic acid film. In particular, the glass transition temperature of the polylactic acid resin may be excessively high, which may lower the flexibility of the film, and the polyolefin-based polyol structural unit or the repeating unit of the soft segment is difficult to properly serve as an initiator, resulting in a low polymerization conversion rate or a high molecular weight polylactic acid. The resin may not be manufactured properly.

On the other hand, the polylactic acid resin film includes an antioxidant together with the polylactic acid resin described above. The antioxidant can suppress the yellowing of the polylactic acid resin to improve the appearance of the film, and can suppress the oxidation or thermal decomposition of the soft segment and the like.

To this end, the polylactic acid resin film is about 100 to 3,000 ppmw, about 100 to 2,000 ppmw, about the amount of the monomer (eg, lactic acid or lactide) added to form the polylactic acid repeating unit of the polylactic acid resin. The antioxidant may be included in an amount of 500 to 1,500 ppmw, or about 1,000 to 1,500 ppmw.

When the content of the antioxidant is too low, the polylactic acid resin may be yellowed by oxidation of a softening component such as the soft segment, and the appearance of the film may be poor. On the other hand, when the content of the antioxidant is too high, the antioxidant may lower the polymerization rate of the lactide, etc., the hard segment containing the polylactic acid repeat unit may not be properly produced, the mechanical properties of the polylactic acid resin And the like may be degraded.

When the antioxidant is included in an optimized content, for example, when the antioxidant is added in an optimized content during polymerization for the production of polylactic acid resin to obtain the polylactic acid resin and the polylactic acid resin film, Productivity can be increased by improving the conversion of polymerization and degree of polymerization. In addition, since the resin may exhibit excellent thermal stability in a film forming process requiring heating of 180 ° C. or higher with respect to the resin, it is possible to suppress the production of a monomer such as lactide or lactic acid or a low molecular material in a cyclic oligomer chain state.

Accordingly, the molecular weight decrease of the polylactic acid resin and the color change (yellowing) of the film are suppressed, and not only have excellent appearance, but also show greatly improved flexibility, and excellent physical properties such as mechanical properties, heat resistance and blocking resistance. The packaging film to be expressed can be provided.

As the antioxidant, one or more selected from the group consisting of hindered phenol antioxidants, amine antioxidants, thio antioxidants and phosphite antioxidants may be used, and other polylactic acid resin films may be used. Various antioxidants known to be available for manufacture can be used.

 However, since the polylactic acid resin may have an ester repeating unit, there is a tendency that the polylactic acid resin is easily oxidized or pyrolyzed during the high temperature polymerization reaction or the high temperature extrusion process. Therefore, as the antioxidant, it is preferable to use thermal stabilizers, polymerization stabilizers or antioxidants of the above-listed series. Specific examples of such antioxidants include phosphoric acid thermal stabilizers such as phosphoric acid, trimethyl phosphate or triethyl phosphate; 2,6-di-t-butyl-p-cresol, octadecyl-3- (4-hydroxy-3,5-di-t-butylphenyl) propionate, tetrabis [methylene-3- (3, 5-di-t-butyl-4-hydroxyphenyl) propionate] methane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxy Benzyl) benzene, 3,5-di-t-butyl-4-hydroxybenzylphosphite diethyl ester, 4,4'-butylidene-bis (3-methyl-6-t-butylphenol), 4, Solids such as 4'-thiobis (3-methyl-6-t-butylphenol) or bis [3,3-bis- (4'-hydroxy-3'-tert-butyl-phenyl) butanoic acid] glycol ester Hindered phenolic primary antioxidants; Amines such as phenyl-α-naphthylamine, phenyl-β-naphthylamine, N, N'-diphenyl-p-phenylenediamine or N, N'-di-β-naphthyl-p-phenylenediamine System secondary antioxidants; Thio such as dilauryl disulfide, dilaurylthiopropionate, distearylthiopropionate, mercaptobenzothiazole or tetramethylthiuram disulfide tetrabis [methylene-3- (laurylthio) propionate] methane (thio) secondary antioxidants; Or triphenyl phosphite, tris (nonylphenyl) phosphite, triisodecylphosphite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite or (1,1'-biphenyl) -4, And phosphite secondary antioxidants such as 4'-diylbisphosphonate tetrakis [2,4-bis (1,1-dimethylethyl) phenyl] ester. Among them, it is most preferable to use a combination of phosphite-based antioxidants and other antioxidants.

In addition to the above-mentioned antioxidants, the polylactic acid resin film may have various known plasticizers, ultraviolet stabilizers, anti-colorants, matte agents, deodorants, flame retardants, weathering agents, antistatic agents, mold release agents, antioxidants, and ions in a range that does not impair the effect thereof. Various additives, such as an exchange agent, a coloring pigment, inorganic or organic particle | grains, may also be further included.

Examples of the plasticizer include phthalic ester plasticizers such as diethyl phthalate, dioctyl phthalate and dicyclohexyl phthalate; Aliphatic dibasic acid ester plasticizers such as di-1-butyl adipic acid, di-n-octyl adipic acid, di-n-butyl sebacic acid, and di-2-ethyl hexyl azaline acid; Phosphoric ester plasticizers such as diphenyl-2-ethylhexyl phosphate and diphenyl octyl phosphate; Hydroxy polyhydric carboxylic acid ester plasticizers such as acetyl citric acid tributyl, acetyl citric acid tri-2-ethyl hexyl and tributyl citric acid; Fatty acid ester plasticizers such as acetyl ricinolic acid methyl and stearic acid diyl; Polyhydric alcohol ester plasticizers such as glycerin tri acetate; Epoxy plasticizers, such as epoxidized soybean oil, epoxidized amani oil fatty acid butyl ester, and octyl epoxy stearate, etc. are mentioned. In addition, examples of the coloring pigment include inorganic pigments such as carbon black, titanium oxide, zinc oxide and iron oxide; Organic pigments such as cyanine-based, phosphorus-based, quinone-based, lerione-based, isoindolinone-based and thio-indigo-based; In order to improve the blocking resistance of other films, inorganic or organic particles may be further included. Examples thereof include silica, colloidal silica, alumina, alumina sol, talc, mica, calcium carbonate, polystyrene, and polymethyl. Methacrylate, silicone, and the like. In addition, it is possible to include various additives known to be usable in the polylactic acid resin or the film, and the specific kind and obtaining method thereof are obvious to those skilled in the art.

The polylactic acid resin may have a number average molecular weight of about 50,000 to 200,000, preferably a number average molecular weight of about 50,000 to 150,000. In addition, the polylactic acid resin may have a weight average molecular weight of about 100,000 to 400,000, preferably a weight average molecular weight of about 100,000 to 320,000. Such molecular weight may affect the processability of the polylactic acid resin or the mechanical properties of the film including the same. When the molecular weight is too small, when melt processing by a method such as extrusion, the melt viscosity is too low may be poor workability when processing into a film, mechanical properties such as strength may be reduced even when processing to a film. On the contrary, when the molecular weight is excessively large, the melt viscosity at the time of melt processing is too high, and the productivity and workability into a film may be greatly reduced.

In addition, the polylactic acid resin may have a molecular weight distribution (Mw / Mn) defined as a ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of about 1.60 to 3.0, preferably about 1.80 to 2.15. As the polylactic acid resin exhibits such a narrow molecular weight distribution, it exhibits proper melt viscosity and melting characteristics when melt processing by extrusion or the like, thereby exhibiting excellent film extrusion state and processability, and include the polylactic acid resin. The film can exhibit mechanical properties such as excellent strength. On the other hand, when the molecular weight distribution is too narrow, the melt viscosity is too large at the processing temperature for extrusion, etc., it may be difficult to process as a film, on the contrary, when the molecular weight distribution is too wide, mechanical properties such as the strength of the film is reduced or It may be difficult to mold itself into the film due to poor melt characteristics such as melt viscosity is too small, or poor film extrusion.

In addition, the polylactic acid resin may have a melting temperature (Tm) of about 145 to 178 ° C, about 160 to 178 ° C, or about 165 to 175 ° C. If the melting temperature is too low, the heat resistance of the film containing the polylactic acid resin may be lowered. If the melting temperature is too high, high temperature is required during melt processing by extrusion or the like, or the viscosity may be too high, resulting in deterioration of processing characteristics of the film. Can be.

The polylactic acid resin, such as the block copolymer contained therein, has a glass transition temperature (Tg) of about 20 to 55 ° C, or about 25 to 55 ° C, or about 30 to 55 ° C. As such polylactic acid resin exhibits such a glass transition temperature range, the flexibility and stiffness of the film containing the resin can be properly maintained and it can be preferably used as a packaging film. If the glass transition temperature of the polylactic acid resin is too low, the flexibility of the film may be improved, but as the strength is too low, slipping, handling, shape retention characteristics, or blocking resistance during packaging processing using the film may be improved. The properties may be poor, and therefore, application to a packaging film may be inappropriate. On the contrary, if the glass transition temperature is too high, the film may have a low flexibility and a high strength, so that the film may not easily be folded and its marks may be lost or the adhesion to the target product may be poor in packaging. In addition, when the film is wrapped, the noise is severely generated, there may be a limit to the application to the packaging film.

On the other hand, the polylactic acid resin may be less than about 1% by weight of the monomer, such as lactide monomers used for the production of the polylactic acid repeat unit, relative to the weight of the polylactic acid resin, more preferably About 0.01 to 0.5% by weight of monomer may remain. The polylactic acid resin film includes a block copolymer having specific structural properties, a polylactic acid resin including the same, and an antioxidant, and thus, most of the lactide monomers used during the manufacturing process participate in polymerization to form a polylactic acid repeating unit. In addition, substantially no depolymerization or decomposition of the polylactic acid resin occurs. For this reason, the polylactic acid resin film may include a minimum amount of residual monomers, for example, residual lactide monomers.

If the residual monomer content is about 1% by weight or more, a odor problem occurs in processing the polylactic acid resin film, and the decrease in the molecular weight of the polylactic acid resin due to the film processing causes a decrease in the strength of the final film, in particular, for food packaging applications. Residual monomers may bleed-out and cause stability problems.

Since the polylactic acid resin film includes an antioxidant, yellowing of the polylactic acid resin may be suppressed, so that the polylactic acid resin film may exhibit a color-b value of 5 or less, and preferably a color-b value of 2 or less. If the color-b value is greater than 5, the appearance of the film may be deteriorated and commodity value may be degraded.

Hereinafter, the manufacturing method of the polylactic acid resin of this invention is demonstrated more concretely, for example.

<Production of Polyolefin-Based Polyol Structural Unit>

First, a hydroxyl group is added to a terminal of a polymer (poly 1,2-butadiene or poly 1,3-butadiene) obtained by conjugate polymerization of a butadiene monomer, and a liquid polybutadiene having a molecular weight in the range of 1,000 to 3,000 is obtained through a hydrogenation reaction. -terminated polybutadiene (HTPB) is formed to obtain a (co) polymer with polyolefinic polyol structural units. This can be done according to a conventional method for preparing polyolefin-based polyol (co) polymers.

<Production of Polyolefin-Based Polyol Repeating Unit A>

Then, the (co) polymer having the polyolefin-based polyol structural unit, the polyfunctional isocyanate compound, and the urethane reaction catalyst are charged in a reactor, and the urethane reaction is performed by heating and stirring. By this reaction, two or more isocyanate groups of the isocyanate compound and the terminal hydroxyl group of the (co) polymer are bonded to form a urethane bond. As a result, a (co) polymer can be formed in which the polyolefin-based polyol structural units have a polyurethane polyol repeating unit in a linear or branched form connected through the urethane bond. This is included as a soft segment of the polylactic acid resin described above. In this case, the polyurethane polyol (co) polymer is a polyolefin-based polyol repeating units (O) are linear or branched in the form of EUEUE or EU (-E) -EUE via a urethane bond (U) at both ends It may be formed in the form having a polyolefin-based polyol repeating unit.

<Production of Polyolefin-Based Polyol Repeating Unit B>

In addition, a (co) polymer, lactic acid (D or L-lactic acid), lactide (D or L-lactide) compound having the polyolefin-based polyol structural unit, and a condensation or ring-opening reaction catalyst are charged to a reactor, heated and stirred. To carry out the polyester reaction or the ring-opening polymerization reaction. By this reaction, the lactic acid (D or L-lactic acid), lactide (D or L-lactide), and the terminal hydroxyl groups of the (co) polymer are bonded to form an ester bond. As a result, a (co) polymer having a polyolefin-based polyol (O) and a polylactic acid repeating unit (L) in a linear or branched form in which polyolefin-based polyol structural units are connected through the ester bond can be formed. In this case, the polyolefin-based polyol and polylactic acid resin (co) polymer is a form in which the polyolefin-based polyol repeating units (O) are linearly bonded in the form of LEOEL through an ester bond (E) and have a polylactic acid repeating unit at both ends. It can be formed as.

Two or more isocyanate groups of the isocyanate compound and the terminal hydroxyl group of the (co) polymer may be combined to form a urethane bond to form a linear or branched bond in the form of L-E-O-E-L-U-L-E-O-E-L to prepare a final polylactic acid resin.

In this case, the polyolefin-based polyol repeating units obtained from the butadiene may be derived from a biomass such as plant resources, so that the polyolefin-based polyol (co) polymer has an organic carbon content (% C _bio ) of biomass origin is about It can be a fairly high value, above 70% by weight.

The urethane reaction can be carried out in the presence of a conventional tin-based catalyst such as stannous octoate, dibutyltin dilaurate, dioctyltin dilaurate and the like. In addition, the urethane reaction may be carried out under reaction conditions for the production of conventional polyurethane resin. For example, after adding an isocyanate compound and a polyolefin-based polyol (co) polymer under a nitrogen atmosphere, the urethane reaction catalyst is added and reacted at a reaction temperature of 70 to 80 ° C. for 1 to 5 hours to form a (co) polymer having a polyolefin polyol repeating unit. It can manufacture.

Subsequently, polycondensation of lactic acid (D or L-lactic acid) or ring-opening polymerization of lactide (D or L-lactide) in the presence of a (co) polymer having an polyolefin-based polyol repeating unit and an antioxidant, It may be prepared in the form of a block copolymer (or polylactic acid resin including the same) and a composition containing an antioxidant. That is, when undergoing such a polymerization reaction, the polylactic acid repeating unit included in the hard segment is formed while the yellowing caused by oxidation of the soft segment is suppressed by an antioxidant, thereby producing the polylactic acid resin, wherein at least a part of the polylactic acid is produced. The polyurethane polyol repeating unit may be bonded to the end of the repeating unit to form a block copolymer.

In addition, a known polylactic acid copolymer of a form in which a prepolymer in which a polyolefin-based polyol and lactide are first bonded, and then the prepolymers are chain-extended with a diisocyanate compound, or the prepolymers Known branched block copolymers reacted and resins containing them can be formed.

Meanwhile, the lactide ring-opening polymerization reaction may be performed in the presence of a metal catalyst including alkaline earth metal, rare earth metal, transition metal, aluminum, germanium, tin or antimony. Specifically, such metal catalysts may be in the form of carbonates, alkoxides, halides, oxides or carbonates of these metals. Preferably, as the metal catalyst, tin octylic acid, titanium tetraisopropoxide, aluminum triisopropoxide, or the like can be used.

In addition, the step of forming a polylactic acid repeating unit such as the lactide ring-opening polymerization reaction described above may be continuously performed in the same reactor in which the urethane reaction is performed. That is, the polyolefin-based polyol polymer and the isocyanate compound may be urethane reacted to form a polymer having a polyolefin-based polyol repeating unit, and then a monomer such as lactide, a catalyst, and the like may be continuously added to form a polylactic acid repeating unit. . As a result, while the polymer having a polyolefin-based polyol repeating unit serves as an initiator, the polylactic acid repeating unit and the polylactic acid resin containing the same can be continuously produced in high yield and high productivity. Similarly, after ring-opening polymerization of the polyolefin-based polyol with an initiator of lactide, chain extension polymerization is performed by continuously adding an isocyanate compound in the same reactor, so that the polylactic acid repeating unit and the polylactic acid resin including the same have high yield and productivity. It can be produced continuously.

As described above, the polylactic acid resin may include a block copolymer (polylactic acid resin) in which specific hard and soft segments are bonded, thereby exhibiting biodegradability of the polylactic acid resin, but also exhibiting improved flexibility. In addition, it is possible to minimize the suction of the soft segment for imparting flexibility, it is also possible to greatly reduce the moisture resistance, mechanical properties, heat resistance, transparency or haze characteristics of the film by the addition of this soft segment.

In addition, since the polylactic acid resin is manufactured to have a predetermined glass transition temperature and optionally a predetermined melting temperature, the film or the like obtained therefrom may exhibit optimized flexibility and stiffness as a packaging material, as well as melt processability. It becomes excellent and the blocking resistance and heat resistance are further improved. Therefore, such polylactic acid resin can be very preferably applied to packaging materials such as films.

In addition, the polylactic acid resin may be used together with an antioxidant to suppress yellowing during manufacture or use, and provide a packaging film showing excellent physical properties such as excellent appearance and merchandise, and greatly improved flexibility and excellent mechanical properties. Makes it possible.

That is, since the polylactic acid resin film of the present invention is manufactured using a polylactic acid resin including a polyolefin-based polyol repeating unit as a soft segment, flexibility of the film may be greatly improved.

In addition, by the resin component consisting of a polyolefin-based polyol of a non-polar soft segment compared to the polylactic acid resin, which is a hard segment, the moisture content is lowered in the entire resin, so that the moisture resistance can be greatly improved.

Such a polylactic acid resin film including a polylactic acid resin is excellent in moisture resistance, mechanical properties, heat resistance, blocking resistance, transparency and processability, and can exhibit optimized flexibility and strength, and is not yellowed. Since it can exhibit good appearance and environmentally friendly properties, it can be very preferably used as a packaging material in various fields. Therefore, this invention provides the packaging film containing the said polylactic acid resin film.

The polylactic acid resin film may have various thicknesses according to each use, and may have a thickness of about 5 to 3,000 μm. For example, when used as a packaging film such as a wrap film or an envelope, it has a thickness of about 5 to 100 μm, preferably about 7 to 50 μm, and more preferably about 7 to 30 μm in terms of flexibility, handleability and strength. Can be.

In addition, the polylactic acid resin film was used at a temperature of 20 ° C. and a relative humidity of 65%, using a 1123 UTM universal testing machine manufactured by Instron, and having a drawing speed of 300 mm / minute and a distance of 100 mm between grips. When tensile testing is performed on specimens of mm, the total Young's modulus in the longitudinal and width directions may be about 350 to 750 kgf / mm 2, preferably about 450 to 650 kgf / mm 2, more preferably about 500 to 600 kgf / mm 2. The range of this Young's modulus sum can reflect the optimized flexibility and strength of the polylactic acid resin film, and this flexibility and strength seems to be due to the above-described structural properties, glass transition temperature and the like.

However, when the total Young's modulus is excessively low, spreading or loosening may occur during film forming and processing of the film, and handling, process permeability, slit processability, or shape retention characteristics may be poor. In addition, when the wrap film is used, the releasability may be insufficient due to the lack of slipperiness of the film, or it may be difficult to efficiently pack the film by deforming the film before surrounding the article or food such as a container. On the contrary, when the Young's modulus sum is excessively high, when the film is folded during the packaging process, a folding line remains as it is, and the appearance is not good, or it may not be deformed depending on the shape of the packaged article or food, resulting in difficulty in packaging.

In addition, when the polylactic acid resin film is subjected to a tensile test under the same conditions as the Young's modulus, in both the longitudinal direction and the width direction, about 10 kgf / mm 2 or more, preferably about 12 kgf / mm 2 or more, more preferably about 15 It may have an initial tensile strength of not less than 30 kgf / mm 2 max. If the initial tensile strength is less than this, the handleability of the film may be poor, and even after packaging, the film may be easily broken, resulting in a risk of damage to the contents.

In addition, the polylactic acid resin film may have a weight change rate of about 3 wt% or less, preferably about 0.01 to 3.0 wt%, and more preferably about 0.05 to 1.0 wt%, when treated at 100 ° C. in a hot air oven for 1 hour. have. These properties reflect the excellent heat resistance and anti-bleed out properties of the polylactic acid resin film. If the weight change rate is about 3 wt% or more, the dimensional stability of the film becomes poor, which means that plasticizers, residual monomers, or additives are extracted, and these components may contaminate the package contents.

The polylactic acid resin film may have a haze of about 12% or less, a transmittance of about 70% or more, preferably a haze of about 10% or less, a transmittance of about 75% or more, and more preferably a haze of About 8% or less and transmittance may be about 80% or more. If the haze is too large or the transmittance is too low, the contents cannot be easily distinguished in film packaging, and the printed image is hard to appear clearly in the multilayer film application in which the printing layer is used.

In addition, when the polylactic acid resin film is used as a packaging film including the same, the moisture resistance is excellent, so that the hydrolysis reaction is suppressed in a high temperature and high humidity environment, thereby maintaining mechanical properties over a long period of time.

The polylactic acid resin film and the packaging film including the same may be used as food packaging materials such as heat sealability, gas barrier properties such as water vapor, oxygen or carbon dioxide, mold release property, and printability, as necessary, within a range that does not impair the effect thereof. Required properties can be given. To this end, a compound having such properties may be blended into a film, or a thermoplastic resin such as an acrylic resin, a polyester resin, a silicone resin, an antistatic agent, a surfactant, a release agent, or the like may be applied to at least one surface of the film. As another method, another film having a function such as polyolefin sealant or the like may be coextruded to be produced in the form of a multilayer film. It may also be produced in the form of a multilayer film by other adhesive or lamination methods.

On the other hand, the packaging film may be prepared according to a conventional method. For example, inflation, sequential biaxial stretching, simultaneous biaxial stretching, and the like may be applied to the polylactic acid resin described above, and then heat-fixed. At this time, the stretched film forming step is to melt-extrude the polylactic acid resin into a sheet by an extruder equipped with a T die, and to cool and solidify the sheet-like molten extrudate to obtain an unstretched film, and then the unstretched film It can advance by the method of extending | stretching to a longitudinal direction and a width direction.

Stretching conditions of the film can be appropriately adjusted according to heat shrinkage characteristics, dimensional stability, strength, Young's modulus and the like. For example, in view of the strength and flexibility of the final packaging film, it is preferable that the stretching temperature is adjusted to be above the glass transition temperature and below the crystallization temperature of the polylactic acid resin. In addition, the stretching ratio may be in the range of about 1.5 to 10 times in the length and width directions, respectively, and the length and the width direction stretching ratio may be adjusted differently.

After forming the stretched film in this manner, the final packaging film is prepared by heat setting, which heat treatment is preferably treated at 100 ° C. or more for about 10 seconds or more for strength and dimensional stability of the film.

The packaging film not only has excellent flexibility and transparency even when stored for a long time, but may also exhibit mechanical properties such as sufficient strength and anti-bleed out properties. In addition, it can exhibit the eco-friendly properties and biodegradability peculiar to polylactic acid resin. Therefore, such a packaging film can be preferably applied as a packaging material in various fields. For example, as well as general consumer goods or grocery general packaging / envelopes, refrigerated / frozen food packaging, shrinkable packaging films, bundle films, sanitary napkins or sanitary napkins, laminate films, shrink label packaging and snack packaging mat films. In addition, it can be widely used as a packaging material for industrial materials such as agricultural multi-film, automotive film protection sheet, garbage bag and compost bag.

As such, the polylactic acid resin of the present invention includes a polyolefin-based polyol repeating unit as a soft segment, so that the flexibility of the film produced using the polylactic acid resin may be greatly improved.

In addition, the moisture content is lowered in the entire resin by a resin component composed of a polyolefin-based polyol of a non-polar soft segment compared to the polylactic acid resin, which is a hard segment, thereby greatly improving moisture resistance. In addition, such a polyolefin-based polyol repeating unit makes it possible to provide a film showing excellent physical properties without deteriorating heat resistance, blocking resistance, mechanical properties or transparency of the polylactic acid resin or a film including the same.

In addition, a polylactic acid resin comprising a polyolefin-based polyol repeating unit and a polylactic-acid repeating unit in which a plurality of polyolefin-based polyol repeating units are linearly or branched connected through a urethane bond or an ester bond, It is possible to provide a film exhibiting excellent flexibility, while having a low moisture content in the entire resin by the polyolefin polyol repeating unit, which is a nonpolar component, has excellent moisture resistance, shows a large molecular weight and a narrow molecular weight distribution, and a polylactic acid repeating unit with a large segment size. Including as, the film produced by using this can exhibit excellent mechanical properties, heat resistance and blocking resistance.

Accordingly, the polylactic acid resin and the polylactic acid resin film including the same have all the problems of the copolymers known in the art, thereby exhibiting excellent overall physical properties and greatly improving flexibility.

Hereinafter, the operation and effects of the invention will be described in more detail with reference to specific examples of the invention. However, these embodiments are only presented as an example of the invention, whereby the scope of the invention is not determined.

The raw materials used in the following examples and comparative examples are as follows:

1. Polyolefin-based polyol repeating units and their corresponding materials

-HTPB 1.0: A liquid polybutadiene having a molecular weight of 1,000 obtained by a hydrogenation reaction by imparting a hydroxyl group to the terminal of a polymer (poly 1,2-butadiene or poly 1,3-butadiene) obtained by conjugate polymerization of butadiene monomers. -terminated polybutadiene: HTPB)

-HTPB 2.0: Liquid polybutadiene (HTPB) having a molecular weight of 2,000 obtained by a hydrogenation reaction by imparting a hydroxyl group to the terminal of a polymer (poly 1,2-butadiene or poly 1,3-butadiene) obtained by conjugate polymerization of butadiene monomers. )

-HTPB 3.0: Liquid polybutadiene (HTPB) having a molecular weight of 3,000 obtained through a hydrogenation reaction by imparting a hydroxyl group to the terminal of a polymer (poly 1,2-butadiene or poly 1,3-butadiene) obtained by conjugate polymerization of butadiene monomers. )

-HTPB 5.0: A liquid polybutadiene (HTPB) having a molecular weight of 5,000 obtained through a hydrogenation reaction by imparting a hydroxyl group to the terminal of a polymer (poly 1,2-butadiene or poly 1,3-butadiene) obtained by conjugate polymerization of a butadiene monomer. )

PEG 8.0: polyethylene glycol; Number average molecular weight 8,000

PBSA 11.0: aliphatic polyester polyols made of 1,4-butanediol and condensates of succinic acid and adipic acid; Number average molecular weight 11,000

2. Diisocyanate compounds and trifunctional or higher isocyanates

HDI: hexamethylene diisocyanate

TDI: 2,4- or 2,6-tolylene diisocyanate (toluene diisocyanate: TDI)

D-L75: Bayer desmodur L75 (trimethylolpropane + 3 toluene diisocyanate)

3. Lactide Monomer

L-lactide or D-lactide: manufactured by Purac, with an optical purity of at least 99.5%

Monomers composed solely of organic carbon of biomass origin

4. Antioxidant etc

TNPP: tris (nonylphenyl) phosphite

U626: bis (2,4-di-t-butylphenyl) pentaerythritoldiphosphite

S412: tetrakis [methane-3- (laurylthio) propionate] methane

PEPQ: (1,1'-biphenyl) -4,4'-diylbisphosphonic acid tetrakis [2,4-bis (1,1-dimethylethyl) phenyl] ester

I-1076: octadecyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate

O3: bis [3,3-bis- (4'-hydroxy-3'-tert-butyl-phenyl) butanoic acid] glycol ester

Production Example  1 to 6: Polylactic acid  Preparation of Resins A to F

An 8 L reactor equipped with a nitrogen gas inlet tube, stirrer, catalyst inlet, outlet condenser and vacuum system was charged with the catalyst with the components and contents as shown in Table 1 below. As the catalyst, 130 ppmw of dibutyltin dilaurate relative to the total reactant content was used. The urethane reaction was carried out at a reactor temperature of 70 ° C. for 2 hours under a nitrogen stream, and 4 kg of L- (or D-) lactide was added thereto to carry out nitrogen flushing five times.

Thereafter, the temperature was raised to 150 ° C. to completely dissolve the L- (or D-) lactide, and the reaction vessel was diluted with 500 ml of toluene such that tin 2-ethylhexylate, the catalyst, was 120 ppmw of the total reactant content through the catalyst inlet. Added in. The reaction was carried out at 185 ° C. for 2 hours under 1 kg of nitrogen pressurization, 200 ppmw of phosphoric acid was added to the catalyst inlet, and then mixed for 15 minutes to inactivate the residual catalyst. Subsequently, unreacted L- (or D-) lactide (about 5% by weight of the initial dose) was removed by vacuum until it reached 0.5 torr. Molecular weight characteristics, Tg, Tm and% C _bio of the obtained resin was measured and shown in Table 1.

Preparation Example 7 Preparation of Polylactic Acid Resin G

In an 8 liter reactor equipped with a nitrogen gas inlet tube, agitator, catalyst inlet, outlet condenser and vacuum system, as shown in Table 1 below, 865 g HTPB2.0 and 3.9 kg L-lactide and 0.1 kg D-lactide And nitrogen flushing was performed five times. The temperature was raised to 150 ° C to completely dissolve the lactide, and 120 ppmw of the tin 2-ethylhexylate, diluted with 500 ml of toluene, was added to the reaction vessel through the catalyst inlet. Subsequently, the reaction was carried out at 185 ° C. for 2 hours under 1 kg nitrogen pressurization, 200 ppmw of phosphoric acid was added to the catalyst inlet, and then mixed for 15 minutes to inactivate the residual catalyst. Unreacted L-lactide (about 5 parts by weight of the initial dose) was removed via vacuum until it reached 0.5 torr. Thereafter, HDI and 120 ppmw of catalyst dibutyltin dilaurate as shown in Table 1 were diluted with 500 ml of toluene and added into the reaction vessel through the catalyst inlet. The reaction was carried out at 190 ° C. for 1 hour under a nitrogen atmosphere, and the molecular weight characteristics, Tg, Tm, and% C _bio of the obtained resin were measured and shown in Table 1.

Preparation Example 8 Preparation of Polylactic Acid Resin H

As shown in Table 1, 885 g of HTPB2.0 and 3.8 kg of L-lactide and 0.2 kg of D-lactide were used, and then through the catalyst inlet, HDI and D-L75 as shown in Table 1 below. Except having used together, it manufactured by the method similar to manufacture example 7. Molecular weight characteristics, Tg, Tm and% C _bio of the obtained resin was measured and shown in Table 1.

Preparation Example 9 Preparation of Polylactic Acid Resin I

In an 8 L reactor equipped with a nitrogen gas inlet tube, a stirrer, a catalyst inlet, an outlet condenser, and a vacuum system, polyol and 4 kg of L-lactide were introduced as shown in Table 1 and subjected to nitrogen flushing five times. The temperature was raised to 150 ° C. to completely dissolve the L-lactide, and 120 ppmw of the catalyst tin 2-ethylhexylate was diluted with 500 ml of toluene and added into the reaction vessel through the catalyst inlet. Subsequently, the reaction was carried out at 185 ° C. for 2 hours under 1 kg nitrogen pressurization, 200 ppmw of phosphoric acid was added to the catalyst inlet, and then mixed for 15 minutes to inactivate the residual catalyst. Unreacted L-lactide was removed by vacuum until it reached 0.5 torr. Molecular weight characteristics, Tg, Tm and% C _bio of the obtained resin was measured and shown in Table 1.

Preparation Example 10 Preparation of Polylactic Acid Resin J

The preparation was carried out in the same manner as in Production Example 9, except that 6 g of 1-dodecanol was added instead of the polyol as shown in Table 1 below. Molecular weight characteristics, Tg, Tm and% C _bio of the obtained resin was measured and shown in Table 1.

Preparation Example 11 Preparation of Polylactic Acid Resin K

In an 8 L reactor equipped with a nitrogen gas inlet tube, a stirrer, a catalyst inlet, an outlet condenser, and a vacuum system, PBSA polyol (polyester polyol) and HDI were introduced as shown in Table 1 and subjected to nitrogen flushing five times. As the catalyst, 130 ppmw of dibutyltin dilaurate relative to the total reactant content was used. The urethane reaction was carried out at a reactor temperature of 190 ° C. for 2 hours under a nitrogen stream, 4 kg of L-lactide was added, the L-lactide was completely dissolved at 190 ° C. in a nitrogen atmosphere, and the total reactant content was passed through the catalyst inlet. 120 ppmw of the counter addition polymerization catalyst Tin2-ethylhexylate and 1,000 ppmw of dibutyltin dilaurate as ester and / or ester amide exchange catalyst were diluted in 500 ml of toluene and added into the reaction vessel. The reaction was carried out at 190 ° C. for 2 hours under 1 kg of nitrogen pressurization, and 200 ppmw of phosphoric acid was added to the catalyst inlet and mixed for 15 minutes to inactivate the residual catalyst. Subsequently, unreacted L-lactide (about 5 weight of the initial dose) was removed by vacuum until it reached 0.5 torr. The molecular weight characteristics, Tg, Tm and% C _bio of the obtained resin was measured and shown in Table 1.

Examples 1-8, and Comparative Examples 1-5: Preparation of Film

The polylactic acid resins prepared in Preparation Examples 1 to 11 were dried under reduced pressure at 80 ° C. under a vacuum of 1 torr for 6 hours, and the extrusion temperature conditions shown in Table 2 in a 30 mm diameter single screw extruder equipped with a T die. Extruded into sheets. The unstretched film was produced by electrostatically casting on the drum cooled to 5 degreeC. After stretching the produced unstretched film three times in the longitudinal direction between the heating rolls under the stretching conditions shown in Table 2, the stretched lengthwise film was fixed with a clip and drawn in a tenter four times in the width direction, The heat treatment was performed at 120 ° C. for 60 seconds while being fixed in the width direction. Through this, a biaxially stretched polylactic acid resin film having a thickness of 20 µm was obtained. The evaluation result of the obtained film is shown together in Table 2.

Experimental Example

(1) NCO / OH: terminal hydroxyl group of an isocyanate group / polyether polyol repeating unit (or (co) polymer) of a diisocyanate compound (e.g., hexamethylene diisocyanate) for formation of a polyolefinic polyol repeating unit Reaction molar ratio.

(2) OHV (KOHmg / g): The polyolefin-based polyol repeating unit (or (co) polymer) was dissolved in dichloromethane and then acetylated, and the acetic acid produced by hydrolysis was measured by titrating with 0.1 N KOH methanol solution. . This corresponds to the number of hydroxy groups present at the ends of the polyolefin polyol repeating units (or (co) polymers).

(3) Mw and Mn (g / mol), molecular weight distribution (Mw / Mn): polylactic acid resin was dissolved in chloroform at a concentration of 0.25% by weight, and gel permeation chromatography (manufacturer: Viscotek TDA 305, column: Shodex LF804) * 2ea), the polystyrene was calculated as the weight average molecular weight (Mw) and number average molecular weight (Mn) as a standard. The molecular weight distribution value was calculated from Mw and Mn thus calculated.

(4) Tg (glass transition temperature, ° C): After using a differential scanning calorimeter (TA Instruments), the sample was melt quenched and measured by raising the temperature to 10 ° C / min. The midline of the baseline and each tangent line near the endothermic curve was Tg.

(5) Tm (melting temperature, ° C): After using a differential scanning calorimeter (TA Instruments), the sample was melted and quenched and then measured at a temperature of 10 ° C / min. The maximum value temperature of the melting endothermic peak of a crystal was made into Tm.

(8) Residual monomer (lactide) content (% by weight): 0.1 g of the resin was dissolved in 4 ml of chloroform, 10 ml of hexane was added, filtered, and quantified by GC analysis.

(7) Content of polyolefin-based polyol repeating unit (wt%): The content of the polyolefin-based polyol repeating unit included in each prepared polylactic acid resin was quantified using a 600 Mhz nuclear magnetic resonance (NMR) spectrometer.

(8) Chip color-b: After calculating | requiring the value using the color-difference meter (CR-410, Konica Minolta Sensing Co., Ltd.) about the resin chip, the average value of 5 tests in total was displayed.

(9) Organic carbon content rate of biomass origin (% C _bio ): Based on ASTM D6866, the organic carbon content rate of biomass origin is measured from the biomass origin material content test by radiocarbon concentration (Percent Modern; C14). It was.

(9) Extrusion State and Melt Viscosity: Polylactic acid resin was extruded into a sheet at a temperature of 200 to 250 ° C. at a temperature of 5 ° C. in a 30 mm diameter single screw extruder equipped with a T die for producing an unstretched sheet. The electrostatic application was cast on the cooled drum. At this time, the melt viscosity of the sheet-like discharge was measured using a Physica Rheometer of Physica, USA. Specifically, using a tool applying a 25 mm parallel plate type shear force, the melt viscosity of the molten resin at shear rate (1 / s) = 1 while maintaining the initial temperature of the discharged material (Complex viscosity, Pa) S) was measured with the Physica Rheometer, and the state of melt viscosity (extrusion state) was evaluated according to the following criteria.

◎: good melt viscosity and good winding on cooling drum,

○: melt viscosity is slightly low, but winding is possible,

X: Melt viscosity is too low and winding is impossible.

(10) Initial tensile strength (kgf / mm2) MD, TD: 150 mm long, 10 mm wide film samples were aged for 24 hours in an atmosphere of temperature 20 ℃, humidity 65% RH, and UTM (manufactured by ASTM D638). : Tensile strength was measured using an INSTRON) universal testing machine under the conditions of drawing speed 300 mm / min, distance between grips 100 mm. The average value of 5 tests in total was expressed as a result. The longitudinal direction of the film was represented by MD and the width direction by TD.

(11) Elongation (%) MD, TD: The elongation until break of the film was measured under the same conditions as the tensile strength of (6) above, and the average value of the five tests in total was expressed as a result. The longitudinal direction of the film was represented by MD and the width direction by TD.

(12) F5 (kgf / mm 2) MD, TD: From the stress-distortion curve obtained in the tensile test of (6) above, the slope of the tangent line which is the point of stress at the time of 5% deformation is obtained, and 5 obtained from this slope is obtained. The value of the stress at the time of% elongation was calculated | required, and the average value of 5 times of tests in total was expressed as a result. The longitudinal direction of the film was represented by MD and the width direction by TD.

(13) F100 (kgf / mm2) MD: From the stress-distortion curve obtained in the tensile test of (6) above, the slope of the tangent line which is the point of stress at the time of 100% deformation is obtained, and 100% elongation obtained from this slope is obtained. The value of the stress at the time was calculated | required, and the average value of 5 times of tests in total was expressed as a result. Measurement was made only for the longitudinal MD of the film.

(14) Young's modulus (kgf / mm2) MD, TD: The same specimen as the tensile test of (6) above, using a UTM (manufacturer: INSTRON) universal testing machine according to ASTM D638, elongation rate 300 mm / min, distance between grips 100 Young's modulus was measured in mm conditions. The average value of 5 tests in total was expressed as a result. These Young's modulus values, in particular, the total value of the Young's modulus measured in the length and width directions correspond to the flexibility of the film, it can be confirmed that the lower the Young's modulus total value is excellent in flexibility. The longitudinal direction of the film was represented by MD and the width direction by TD.

(15) Moiré (Horizontal): When the film is extruded by compounding two kinds of resins having different molecular weights or resins and plasticizers, the degree of moiré caused by the difference in melt viscosity is measured in the A4 size film sample. Evaluation was made according to the standard.

◎: no wave pattern

(Circle) the occurrence of the water wave within three

X: Five or more wave patterns (lines) occur.

(16) 100 ° C. weight change rate (%): The film sample was aged for 24 hours in an atmosphere of a temperature of 23 ° C. and a humidity of 65% RH, and the weight before heat treatment was measured. Thereafter, the mixture was treated in a hot air oven at 100 ° C. for 60 minutes, and aged again under the same conditions as before the treatment, and then weighed. The results were calculated from the weight ratio before and after the heat treatment before and after the weight change.

(17) Pinhole Generation and Absorption Resistance Characteristics: After the heat treatment of (12), the surface of the film sample was observed to determine whether pinholes were generated. In addition, the degree to which the low molecular weight plasticizer component was absorbed to the film surface by the touch was evaluated according to the following criteria in the A4 size film sample.

◎: no pinhole and no aspiration,

○: less than 5 pinholes or aspiration, but not severe,

X: Five or more pinholes or severe aspiration generation.

(18) Haze (%) and transmittance (%): The film samples were aged for 24 hours in an atmosphere of a temperature of 23 ° C. and a humidity of 65% RH in advance, followed by other methods using a haze meter (model name: Japan NDH2000) according to JIS K7136. It measured about three parts and computed the average value as a result.

(19) Blocking resistance: Using the COLORIPTP type (manufactured by Coolz) of the stamping foil, the antistatic surface of the film sample was aligned with the printing surface, and left for 24 hours at a temperature of 4O &lt; 0 &gt; C and a pressure of 1Kg / cm &lt; ² &gt; The blocking state of the prevention layer and the printing surface was observed. Based on these observations, the blocking resistance between the antistatic layer (A layer) and the printing surface of the in-mold transfer foil was evaluated. At this time, up to ○ satisfies the practical performance.

◎: No change

○: slight surface change (5% or less),

X: 5% or more peeling

(20) Yellowness of film: The film sample is crushed by a crusher, dehumidified, dried and crystallized at 120 DEG C, and then melted at about 200 DEG C by a small single screw extruder (Rheomics 600 extruder, Haake) and chip again. It was made. The difference of the color value of the chip | tip before and after the said film processing was measured, and the yellowing coloring degree was evaluated by the following reference | standard.

◎: less than 2 yellowing,

○: yellowing slightly below 5,

X: Yellowing is severe in excess of 5 seconds.

(21) Moisture resistance retention rate (%): The initial tensile strength change was measured after 30 days elapsed in a film sample having a length of 150 mm and a width of 10 mm in a temperature of 40 ° C. and a humidity of 90% RH.

Suzy
A Suzy
B Suzy
C Suzy
D Suzy
E Resin F Suzy
G Suzy
H Suzy
I Suzy
J Suzy
K HTPB 2.0 (g) 475 104 865 885 HTPB 1.0 (g) 231 208 HTPB 3.0 (g) 490 HTPB 5.0 (g) 1607 PEG 8.0 (g) 2400 PBSA 11.0 (g) 800 HDI (g) 17 32 19 2 122 55 3 9.5 TDI (g) 36 D-L75 (g) 3 NCO / OH 0.65 0.85 0.92 0.55 0.5 0.96 0.8 0.8 OHV (KOHmg / g) 9 6  7  29 7 2 4 4 47 3 TNPP (g) 4 2 U626 (g) 2 3 6 9.6 0.8 3 PEPQ (g) 4 S412 (g) 2 I-1076 (g) One O3 (g) 2 L-lactide (g) 4000 4000 4000 4000 3900 3800 4000 4000 4000 D-lactide (g) 4000 4000 100 200 Antioxidant
Content (ppmw) 1000 1000 1000 1500 1500 2400 200 500 0 750 0 IV (dl / g) 0.95 1.38 1.5 0.66 0.9 1.25 0.2 1.55 Mn
(× 1,000, g / mol) 75 120 145 62 70 61 129 121 14 128 65 Mw
(× 1,000, g / mol) 165 240 320 108 152 110 280 340 26 295 185 MWD 2.2 2.0 2.2 1.7 2.2 1.8 2.2 2.7 1.9 2.3 2.8 Tg (℃) 50 49 54 55 46 30 40 42 15 65 18 Tm (℃) 171 168 174 174 164 145 155 153 130 176 85, 165 Color b 3 2 2 3 5 8 8 7 5 4 13 Polyolefin polyol repeat unit content (wt%) 11% 11% 6% 5% 15% 30% 19% 18% 39% 0% 18% Residual monomer content (wt%) 0.45 0.4 0.3 0.65 0.55 0.78 0.92 0.88 8 0.3 2.5 Weight percent of biomass C
(ASTM D6866) 88% 90% 92% 94% 85% 69% 79% 81% 57% 97% 78%

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Resin 1 (wt%) A 100 B 100 C 100 D 100 E 100 F 50 G 100 H 100 J 100 I 40 PDO 10 PBSA 10 K 100 Resin 2 (wt%) J 50 J 60 J 90 J 90 Extrusion temperature
(℃) 220 230 240 200 200 230 200 240 240 200 200 200 200 Melt Viscosity (Pao) 1000 1500 2000 550 1000 1400 1500 2500 2000 250 1200 1400 1400 Extrusion State ◎ ◎ ◎ ○ ◎ ◎ ◎ ○ ◎ X ◎ ○ ◎ Drawing temperature
(℃) 81 80 80 95 80 85 90 90 80 80 80 80 80 Drawing time (sec) 20 20 20 30 20 20 20 20 20 20 20 20 20 Elongation ratio 3 × 4 3 × 4 3 × 4 3 × 4 3 × 4 3 × 4 3 × 4 3 × 4 3 × 4 3 × 4 3 × 4 3 × 4 3 × 4 Film thickness
(um) 20 20 20 21 20 20 20 20 20 20 20 20 20 Initial tensile strength (kgf / ㎡) MD 10 13 15 10 11 13 14 10 20 2.5 15 9 7 Initial tensile strength (kgf / ㎡) TD 12 18 22 14 13 18 11 12 26 3.1 18 10 8 Tensile Strength Total
(kgf / ㎡) 21 31 37 23 24 31 25 21 46 5.6 33 19 15 Elongation (%) MD 100 130 120 124 140 142 160 65 124 152 145 135 212 Elongation (%) TD 65 60 70 72 90 88 98 45 86 89 66 98 105 F5
(kgf / mm2) MD 5 8 9 4.5 4.5 7.5 8.5 5.5 9.8 1.5 8.7 7.9 5 F5
(kgf / ㎡) TD 8 10 10 7 7 11 7.5 5.3 12 2.1 11 9.8 6.5 F100
(kgf / mm2) MD 7.2 13 12 6 10 14.2 4.8 4.5 17 1.8 5.6 6.1 4.2 Young's modulus
(kgf / mm2) MD 296 260 160 222 210 223 185 320 386 179 338 327 150 Young's modulus
(kgf / ㎡) TD 320 310 418 319 240 244 202 355 460 241 419 412 165 Young's modulus total (kgf / ㎡) 616 570 578 541 450 467 387 675 846 420 757 739 315 Wave pattern ◎ ◎ ◎ ◎ ◎ ◎ ◎ ○ ◎ X ○ ○ ◎ Pinhole generation ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ X ◎ ○ X 100 ℃ weight change rate (%) 0.2 0.2 0.2 0.4 0.3 0.4 2.5 1.3 0.2 6 5.1 5.5 7.2 Bleed
out ◎ ◎ ◎ ◎ ◎ ◎ ○ ◎ ◎ ◎ X X ○ Haze (%) 9 8 5 5 12 8 11 12 0.7 0.7 13 16 2.1 Transmittance (%) 80 81 84 84 78 80 78 76 94 87 70 68 84 Blocking resistance ◎ ◎ ◎ ◎ ○ ○ ○ ○ ◎ X ○ ○ X Yellowing Coloration ◎ ◎ ◎ ◎ ◎ ◎ ○ ○ ◎ X X X X Moisture Resistance Tensile Strength
% Retention 91 92 86 85 94 96 97 98 78 69 72 75 50

Referring to Table 2, Examples 1 to 5 or Examples 7 to 8 has a content of the softening component (polyolefin-based polyol repeating unit) in the polylactic acid resin is 5 to 35wt%, low color b value, It includes an antioxidant, and includes a polylactic acid resin of the present invention having physical properties such as weight average molecular weight of 100,000 to 400,000, molecular weight distribution of 1.80 to 3.0, Tg 20 to 55 ° C, and Tm 145 to 178 ° C. In addition, Example 6 was manufactured using the composition which mixed the polylactic acid resin (resin F) and general polylactic acid resin (resin J) and antioxidant which fall within the scope of the present invention.

The films of Examples 1 to 8 all have excellent mechanical properties with an initial tensile strength of 10 kgf / mm 2 or more in the length and width directions, and also have excellent flexibility with a Young's modulus of 750 kgf / mm 2 or less in the length and width directions. Indication was confirmed. In addition, it was confirmed that such a Young's modulus sum was not too low and maintained an appropriate range, and the intensity | strength also showed an appropriate level. In addition, the weight change rate when treated in a 100 ° C. hot air oven for 1 hour is 3 wt% or less, the haze is 12% or less, the transmittance is 75% or more, and the blocking resistance is also excellent, such as transparency, haze and blocking resistance. And excellent physical properties such as heat resistance. In addition, the films of Examples 1 to 8 were also good in appearance and excellent in thermal stability, so that even after the film extrusion process, the color-b value change (yellowing coloration) was not severe, and the moisture resistance of the film was particularly excellent.

On the other hand, the film of Comparative Example 1 made of general polylactic acid resin J had a total length and width direction Young's modulus exceeding 750 kgf / mm 2, which was insufficient in flexibility and poor in moisture resistance, making it difficult to be used as a packaging film. In addition, in the case of the film of Comparative Example 2 prepared by using the resin J and the resin I together, the difference in melt viscosity between the two resins is too large, the extrusion state is poor, and the problem that a wave pattern occurs in the final film also occurred . Moreover, due to the high residual lactide dilution, pinholes were generated on the film, resulting in poor film appearance, poor blocking resistance and poor moisture resistance, and poor initial tensile strength, transmittance, and yellowing coloration.

In Comparative Examples 3 and 4, poly (1,3-propanediol) having a number average molecular weight of 2,400 and 1,4 having a number average molecular weight of 11,000, respectively, were used as plasticizer components without using a polyolefin-based polyol repeating unit which is a resin softening component. An aliphatic polyester polyol made of a butanediol and a condensate of succinic acid and adipic acid is simply compounded and mixed into resin J into a film. The films of Comparative Examples 4 and 5 were not completely dispersed in the resin of the plasticizer component, so that the haze of the film was high, the yellowing color was poor, and the plasticizer component was bleeded out from the surface of the film after a lapse of time. , Moisture resistance was poor.

In addition, the film of Comparative Example 5 is a polyester polyol repeating unit is introduced, the molecular weight distribution is wide It is made of a copolymer. Such films showed relatively good flexibility as the softening component polyurethane was randomly introduced into a small segment size, but exhibited poor heat resistance due to low Tm and blocking as polylactic acid repeating units were introduced into a relatively small segment size. Difficulties in filming were identified as a problem. In addition, the low compatibility of the polyester polyol and polylactic acid used for the formation of the softening component was found to result in high haze value and low transparency of the film, and the molecular weight was determined by the ester and / or ester amide exchange reaction during resin production. It was confirmed that the distribution was wide, resulting in non-uniform melting characteristics, poor film extrusion state, and lowered mechanical properties, and very poor moisture resistance.

In addition, due to the high residual lactide content, relatively high color-b value, and the like of the films of Comparative Examples 3 to 5, significant appearance defects were observed even in the film state, and a weight change rate of 100 ° C., which is inappropriate for commercial application, was observed. . In addition, as the film of Comparative Example 5 requires the use of an excessive amount of catalyst during the preparation of the resin, it appears that the decomposition of the polylactic acid resin is induced during the production or use of the film. It was confirmed that the stability of the film was poor by increasing the weight change rate at.

Claims (18)

A hard segment comprising a polylactic acid repeating unit represented by Formula 1 below;
The polyolefin-based polyol structural units of Formula 2 include a soft segment including a polyolefin-based polyol repeating unit connected linearly or branched through a urethane bond,
Polylactic acid resin having an organic carbon content rate (% C _bio ) of biomass origin defined by Equation 1 below 60% by weight or more; And
A polylactic acid resin film comprising an antioxidant in an amount of 1,000 to 1,500 ppmw based on the amount of monomer added for forming the polylactic acid repeating unit:
[Formula 1]

[Formula 2]

[Equation 1]
% C = _Bio (poly ¹⁴ C isotope ratio by weight of the ¹² C isotope of carbon atoms of the lactic acid resin) / ⁽¹⁴ C isotope ratio by weight of the ^bio-12 C isotope of carbon atoms of the mass origin standard)
In Chemical Formulas 1 and 2, n is an integer of 700 to 5,000, m + 1 is an integer of 5 to 200.
The method of claim 1,
The polylactic acid resin film having a content of ¹⁴ C isotopes in the carbon atoms of the polylactic acid resin is 7.2 × 10 ⁻¹¹ wt% to 1.2 × 10 ⁻¹⁰ wt%.
The method of claim 1,
The polylactic acid resin film, wherein the soft segment comprises 70% by weight or more of organic carbon of biomass origin defined by Equation 1 (% C _bio ).
The method of claim 1,
Wherein said polylactic acid resin has a number average molecular weight of 50,000 to 200,000, and a weight average molecular weight of 100,000 to 400,000.
The method of claim 1,
And a polylactic acid resin film having a glass transition temperature (Tg) of 20 to 55 ° C and a melting temperature (Tm) of 145 to 178 ° C.
The method of claim 1,
The urethane bond is a polylactic acid resin film formed by reaction of a hydroxyl group at the end of the polyolefin-based polyol structural unit with an isocyanate compound having a diisocyanate or a bifunctional group or more.
The method of claim 1,
The polylactic acid resin film, wherein the polylactic acid resin comprises a block copolymer in which the terminal carboxyl group of the polylactic acid repeating unit included in the hard segment is connected by an ester bond to the terminal hydroxyl group of the polyolefin-based polyol structural unit included in the soft segment.
The method of claim 7, wherein
The polylactic acid resin film further comprises a polylactic acid homopolymer, wherein the polylactic acid resin is not bonded to the polyolefin-based polyol repeating unit.
The method of claim 1,
A polylactic acid resin film in which the polymer of the polyolefin-based polyol repeating unit has a number average molecular weight of 1,000 to 100,000.
The method of claim 6,
The polylactic acid resin film whose reaction molar ratio of the hydroxyl group of the said polyolefin type polyol structural unit terminal, and the isocyanate group of the isocyanate compound of a diisocyanate or a bifunctional group or more is 1: 0.50-1: 0.99.
The method of claim 1,
The polylactic acid resin film, polylactic acid resin film containing 65 to 95 parts by weight of the hard segment and 5 to 35 parts by weight of the soft segment with respect to 100 parts by weight of the polylactic acid resin.
delete The method of claim 1,
Polylactic acid resin film which shows color-b value of 5 or less.
The method of claim 1,
A polylactic acid resin film having less than 1% by weight of a monomer, based on the total weight of the polylactic acid resin.
The method of claim 1,
The polylactic acid resin film comprising at least one antioxidant selected from the group consisting of hindered phenol-based antioxidants, amine-based antioxidants, thio-based antioxidants, and phosphite-based antioxidants.
The method of claim 1,
Polylactic acid resin film having a thickness of 5 to 3,000 μm.
The method of claim 1,
The total Young's modulus in the length and width directions is 350 to 750 kgf / mm 2, the initial tensile strength is 10 kgf / mm 2 or more, and the weight change rate when treated at 100 ° C. hot air oven for 1 hour is 0.01 to 3.0 wt%, and haze Is 12% or less, transmittance is 75% or more, and the initial tensile strength retention of the film is 80% or more after 30 days in an atmosphere of 40 ° C. and 90% RH humidity.
A packaging film comprising the polylactic acid resin film according to any one of claims 1 to 11 and 13 to 17.