Poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition and film containing the same

Abstract

The present invention provides a poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition containing a poly(lactic acid-b-3-hydroxypropionic acid) block copolymer and poly(3-hydroxypropionic acid), and having an average haze of less than 4.0, and a film containing the same.

Description

Technical Field

[0001] [Cross - reference to Related Applications] This application claims the benefit of priority based on Korean Patent Application No. 10 - 2022 - 0176832 filed on December 16, 2022 and Korean Patent Application No. 10 - 2023 - 0182742 filed on December 15, 2023, and all the contents disclosed in the documents of the Korean patent applications are included as part of this specification.

[0002] The present invention relates to a poly(lactic acid - b - 3 - hydroxypropionic acid) block copolymer composition and a film containing the same.

Background Art

[0003] Polylactic acid (PLA) is a plant - derived resin obtained from plants such as corn, has biodegradable properties, and is attracting attention as an excellent material friendly to the environment. Different from existing petroleum - based resins such as polystyrene resin, polyvinyl chloride resin, and polyethylene in use, polylactic acid has effects such as preventing depletion of petroleum resources and suppressing carbon dioxide emissions, so it can reduce environmental pollution, which is a shortcoming of petroleum - based plastic products. Therefore, as the problem of environmental pollution caused by waste plastics and the like emerges as a social issue, efforts are being made to expand the application range of polylactic acid to product fields where general plastics (petroleum - based resins) such as food packaging materials and containers, and electronic product cases were used.

[0004] However, compared with existing petroleum - based resins, polylactic acid is inferior in impact resistance and heat resistance, and has limitations in the application range. Also, its tensile strength is weak, and transparency is required depending on the application field, but it is difficult to adjust the physical properties of polylactic acid, so there are limitations as a general - purpose resin.

[0005] In order to improve the above-mentioned disadvantages, research on copolymers containing other repeating units in polylactic acid has been underway, and in particular, 3-hydroxypropionic acid has attracted attention as a comonomer. However, the physical properties exhibited vary depending on the degree of introduction of 3-hydroxypropionic acid, and if the degree of introduction is not adjusted, the inherent physical properties of polylactic acid may be inhibited.

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present invention is to provide a poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition having excellent transparency and a film containing the same.

Means for Solving the Problems

[0007] According to one embodiment of the present invention, there is provided a poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition containing a poly(lactic acid-b-3-hydroxypropionic acid) block copolymer and poly(3-hydroxypropionic acid) and having an average haze of less than 4.0 as measured by ASTM D1003.

[0008] According to one embodiment of the present invention, there is provided a film containing the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition.

[0009] Hereinafter, the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition according to a specific embodiment of the invention and a film containing the same will be described in more detail.

[0010] Throughout this specification, unless otherwise specifically mentioned, "comprising" or "containing" means including a certain component (or constituent) without any special limitation, and shall not be construed as excluding the addition of other components (or constituents).

[0011] Also, unless otherwise specified herein, weight-average molecular weight, number-average molecular weight, etc. of poly(3-hydroxypropionic acid), poly(lactic acid-b-3-hydroxypropionic acid) block copolymer, etc. can be measured using gel permeation chromatography (GPC). Specifically, after dissolving the polymer or copolymer in chloroform to a concentration of 2 mg / ml, 20 μl is injected into the GPC, and GPC analysis is performed at 40°C. At this time, chloroform is used as the mobile phase of the GPC, flowing in at a flow rate of 1.0 mL / min. Two Agilent Mixed-B columns are connected in series and used, and an RI detector (RI Detector) is used as the detector. The Mw value, etc. is derived using a calibration curve formed using polystyrene standard specimens. The weight-average molecular weights of the polystyrene standard specimens used are 12 types: 162 g / mol, 580 g / mol, 1,180 g / mol, 4,870 g / mol, 9,310 g / mol, 17,120 g / mol, 75,050 g / mol, 200,500 g / mol, 448,500 g / mol, 10,690,000 g / mol, 3,022,000 g / mol, and 6,545,000 g / mol.

[0012] In this specification, the haze can be a value measured by NDH5000W of Nippon Denshoku Co., Ltd.

[0013] According to one embodiment of the invention, provided is a poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition containing a poly(lactic acid-b-3-hydroxypropionic acid) block copolymer and poly(3-hydroxypropionic acid), and having an average haze (Haze) of less than 4.0 as measured by ASTM D1003.

[0014] The inventors of the present invention found that when a composition containing a poly(lactic acid-b-3-hydroxypropionic acid) block copolymer contains poly(3-hydroxypropionic acid) at a predetermined content in addition to the block copolymer, the average haze (Haze) is less than 4.0 and the physical properties such as transparency are excellent, and thus completed the present invention.

[0015] In addition, a film containing such a composition containing a poly(lactic acid-b-3-hydroxypropionic acid) block copolymer is also excellent in physical properties such as transparency, and can be applied to materials such as food packaging materials and optical films that require transparency.

[0016] The poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition according to the above embodiment contains a poly(lactic acid-b-3-hydroxypropionic acid) block copolymer and poly(3-hydroxypropionic acid).

[0017] The poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition may have an average haze (Haze) measured by ASTM D1003 of less than 4.0, 3.9 or less, 3.8 or less, or 0.5 or more and 3.7 or less. When the average haze (Haze) of the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition is excessively high, there is a problem that transparency does not appear.

[0018] In addition, the standard deviation between the positions of the haze values of the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition may be 0.400 or less, 0.300 or less, or 0.100 or more and 0.250 or less.

[0019] The poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition may have a UV transmittance of 80% or more, 82% or more, 83% or more, 84% or more, 85% or more, 86% or more, 87% or more, 88% or more, 89% or more, or 90% or more. Also, although the upper limit of the UV transmittance is theoretically 100%, as an example, it may be 99.5% or less, 99.0% or less, 98.5% or less, or 98.0% or less. The UV transmittance can be measured by attaching the composition to an ultraviolet-visible spectrometer (UV-visible spectrometer, Agilent8453) after producing a film having a thickness of approximately 80 μm, and at this time, the transmittance value in the 480 nm region can be confirmed.

[0020] The poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition according to the above-described embodiment may contain the poly(3-hydroxypropionic acid) in an amount of more than 0% by weight and not more than 7.0% by weight, 1.0% by weight or more and 6.5% by weight or less, 2.0% by weight or more and 6.0% by weight or less, or 3.0% by weight or more and 6.0% by weight or less, based on 100% by weight of the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition.

[0021] By containing the poly(3-hydroxypropionic acid) in a predetermined content based on 100% by weight of the total content of the composition, the composition can exhibit optical properties such as transparency with an average haze of less than 4.0. On the other hand, when the poly(3-hydroxypropionic acid) is contained in an excessive amount, there is a problem that crystallization due to phase separation becomes faster and the average haze increases, resulting in opacity.

[0022] The "poly(3-hydroxypropionic acid)" includes repeating units derived from 3-hydroxypropionic acid and may include repeating units represented by the following Chemical Formula 2.

Chemical Formula

[0023] As described later, the poly(3-hydroxypropionic acid) can be ring-opening polymerized with lactide to produce the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer. Therefore, the poly(3-hydroxypropionic acid) contained in the composition may be the poly(3-hydroxypropionic acid) that was charged into the reactor for the production of the block copolymer but remained in the composition without reacting with the lactide. By satisfying the content of the poly(3-hydroxypropionic acid) remaining in such a composition within the above range, the composition can be excellent in optical properties such as transparency.

[0024] In addition, the poly(3-hydroxypropionic acid) contained in the composition can be the poly(3-hydroxypropionic acid) used for additional mixing with the block copolymer after the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer is produced by ring-opening polymerization.

[0025] Therefore, the content of the poly(3-hydroxypropionic acid) contained in the composition can be the total of the content of the unreacted residual poly(3-hydroxypropionic acid) with the lactide and the content of the residual poly(3-hydroxypropionic acid) introduced for additional mixing with the block copolymer.

[0026] On the other hand, the content of the poly(3-hydroxypropionic acid) contained in the composition, in particular, the content of the unreacted residual poly(3-hydroxypropionic acid) with the lactide can be controlled by the ratio of vinyl groups in the end groups of the poly(3-hydroxypropionic acid), the number average molecular weight, and the like.

[0027] The poly(3-hydroxypropionic acid) contained in the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition according to the embodiment may have a vinyl group ratio in the end groups of 40 mol% or less, 35 mol% or less, 1 mol% or more, 30 mol% or less, 2 mol% or more, or 25 mol% or less, 3 mol% or more. If the ratio of vinyl groups in the end groups of the poly(3-hydroxypropionic acid) is excessively high, chain extension of the poly(3-hydroxypropionic acid) does not occur well. When producing a poly(lactic acid-b-3-hydroxypropionic acid) block copolymer with the poly(3-hydroxypropionic acid), a large amount of unreacted poly(3-hydroxypropionic acid) may remain, and optical properties such as the transparency of the composition containing the block copolymer may deteriorate.

[0028] The vinyl group is generated by a side reaction that occurs during the polymerization of 3-hydroxypropionic acid into poly(3-hydroxypropionic acid). However, the equivalent ratio of each functional group (hydroxyl group, carboxyl group) acts as a factor that deviates from the equivalent ratio in important polycondensation reactions, inhibiting the reaction rate and making it difficult to obtain high-molecular-weight polymers. In addition, if a vinyl group is present in poly(3-hydroxypropionic acid), there is a problem that chain extension of poly(3-hydroxypropionic acid) through additional modification does not occur well. Therefore, since the poly(3-hydroxypropionic acid) has few vinyl groups at the terminal groups, there is an advantage that the above disadvantages are fundamentally reduced.

[0029] The poly(3-hydroxypropionic acid) can be produced by polycondensing 3-hydroxypropionic acid under specific conditions to produce poly(3-hydroxypropionic acid) with a low ratio of vinyl groups at the terminal groups. For example, by controlling the polymerization temperature and the like, poly(3-hydroxypropionic acid) with a low ratio of vinyl groups can be produced.

[0030] The ratio of the terminal groups of the poly(3-hydroxypropionic acid) can be calculated by using a Buker 500MHz NMR model equipment 1 to calculate the ratio of vinyl groups to the total end groups through 1H-NMR measurement. For example, the polymer can be dissolved in d-CDCl3 at a concentration of 8 mg / ml and measured, and calculated by the following formula 1.

Equation

[0031] In the above formula 1, a is the area value of 1H of C=C at 6.3 ppm, b is the area value of 2H of HO-CH2- at 3.8 ppm.

[0032] Further, the poly(3-hydroxypropionic acid) may have a number average molecular weight of 5,000 or more and 300,000 or less, 7,000 or more and 250,000 or less, 8,000 or more and 200,000 or less, 9,000 or more and 180,000 or less, 10,000 or more and 150,000 or less.

[0033] Further, the poly(3-hydroxypropionic acid) may have a weight average molecular weight of 16,000 or more, 17,000 or more, 18,000 or more, 19,000 or more, or 20,000 or more, and 400,000 or less, 350,000 or less, 300,000 or less, 250,000 or less, 230,000 or less, 200,000 or less, 190,000 or less, 180,000 or less, 170,000 or less, or 60,000 or less.

[0034] When the number average molecular weight and / or the weight average molecular weight of the poly(3-hydroxypropionic acid) is excessively low, the effect of improving physical properties that the poly(3-hydroxypropionic acid) can impart may decrease. When the number average molecular weight and / or the weight average molecular weight is excessively high, thermal decomposition may occur during the ring-opening polymerization process, resulting in the formation of vinyl groups instead, and the reactivity may decrease.

[0035] Further, the poly(3-hydroxypropionic acid) may have a molecular weight distribution (Mw / Mn) of 1.6 or more, 1.7 or more, 1.8 or more, 1.9 or more, or 2.0 or more, and 3.4 or less, 3.3 or less, 3.2 or less, or 3.1 or less.

[0036] The poly(lactic acid-b-3-hydroxypropionic acid) block copolymer can be a block copolymer obtained by ring-opening polymerization of lactide with poly(3-hydroxypropionic acid). While the poly(lactic acid-b-3-hydroxypropionic acid) exhibits excellent tensile strength and elastic modulus of the polylactic acid block, the poly(3-hydroxypropionic acid) block reduces the glass transition temperature (Tg) to increase flexibility and improves mechanical properties such as impact strength, thereby preventing the poor elongation rate and easy breakage (brittleness) characteristics of polylactic acid.

[0037] Such a block copolymer means a poly(3-hydroxypropionic acid)-polylactide block copolymer containing polylactide repeating units and poly(3-hydroxypropionic acid) repeating units. Also, the category of polymers that can be referred to as the "poly(lactic acid-b-3-hydroxypropionic acid) block copolymer" includes polymers in all states after the ring-opening polymerization and the formation process of repeating units are completed. For example, polymers in unpurified or purified states after the completion of the ring-opening polymerization, polymers contained in liquid or solid resin compositions before product molding, or polymers contained in plastics or textiles after the completion of product molding, etc. can all be included.

[0038] As described above, the end groups of the poly(3-hydroxypropionic acid) can have a hydroxy group, a carboxy group, a vinyl group, etc. When the hydroxy group and / or alkoxy group at the end of the poly(3-hydroxypropionic acid) is added to the ring-opening polymerization reaction of the lactide monomer, the lactide monomer begins to be added (inserted) from the end, and as a result, the block copolymer can be produced. Therefore, if the content of the vinyl group in the end groups of the poly(3-hydroxypropionic acid) increases, it may be difficult to perform ring-opening polymerization with lactide, resulting in a large amount of residual lactide and poly(3-hydroxypropionic acid), and the physical properties such as the optical properties of the composition may deteriorate.

[0039] Meanwhile, the poly(3-hydroxypropionic acid) not only serves as a polymerization initiator as described above, but also improves the mechanical properties, such as flexibility and impact strength, of the final block copolymer by being contained as a repeating unit in the block copolymer.

[0040] The poly(lactic acid-b-3-hydroxypropionic acid) block copolymer can be represented by the following Chemical Formula 1: [ka]

[0041] In the above Chemical Formula 1, m is an integer from 100 to 1000; n is an integer from 500 to 4000.

[0042] The m may be 120 to 350. The m refers to the repeat number of the 3-hydroxypropionic acid-derived monomer, and by introducing it within this range, it is possible to adjust physical properties such as transparency while maintaining the inherent physical properties of polylactic acid. More preferably, m is 130 or more, 140 or more, 150 or more, 160 or more, 170 or more, 180 or more, 190 or more, or 200 or more; and may be 340 or less, 330 or less, 320 or less, 310 or less, or 300 or less.

[0043] The n may be 1000 to 2500. The n refers to the number of repeating units of lactide-derived monomers. More preferably, n is 1100 or more, 1200 or more, 1300 or more, 1400 or more, or 1500 or more; and may be 2400 or less, 2300 or less, 2200 or less, 2100 or less, or 2000 or less.

[0044] Also, the relative ratio (m / n) of the monomers can be from 0.05 to 0.20. Within the range of m / n, physical properties such as transparency can be adjusted while maintaining the physical properties inherent to polylactic acid. More preferably, m / n is 0.06 or more, 0.07 or more, or 0.08 or more; and can be 0.19 or less, 0.18 or less, 0.17 or less, 0.16 or less, or 0.15 or less. If the poly(3-hydroxypropionic acid) is contained in an excessively small amount relative to the polylactic acid, the brittleness may increase. If the poly(3-hydroxypropionic acid) is contained in an excessively large amount relative to the polylactic acid, the molecular weight may decrease, resulting in a reduction in processability and heat resistance stability.

[0045] The poly(lactic acid-b-3-hydroxypropionic acid) block copolymer contains a poly(3-hydroxypropionic acid) block. It may be a poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition containing 1 wt% or more and 9 wt% or less of the poly(3-hydroxypropionic acid) block based on 100 wt% of the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition.

[0046] The weight average molecular weight (Mw) of the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer, measured using gel permeation chromatography (GPC), is 50,000 to 600,000 g / mol, more specifically 50,000 g / mol or more, 70,000 g / mol or more, or 100,000 g / mol or more, and has a weight average molecular weight of 550,000 g / mol or less, 500,000 g / mol or less, 450,000 g / mol or less, 300,000 g / mol, 250,000 g / mol or less, 200,000 g / mol or less, or 150,000 g / mol or less. If the weight average molecular weight of the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer is excessively small, the overall mechanical properties may be significantly reduced. If the weight average molecular weight is excessively large, the process may be difficult, and the processability and elongation rate may be reduced.

[0047] The number average molecular weight (Mn) of the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer, measured using gel permeation chromatography (GPC), is 5,000 to 400,000 g / mol, more specifically 5,000 g / mol or more, 10,000 g / mol or more, or 20,000 g / mol or more, and has a number average molecular weight of 350,000 g / mol or less, 300,000 g / mol or less, 250,000 g / mol or less, 200,000 g / mol or less, 150,000 g / mol or less, 100,000 g / mol or less, or 90,000 g / mol or less or 80,000 g / mol or less. If the number average molecular weight of the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer is excessively small, the overall mechanical properties may be significantly reduced. If the number average molecular weight is excessively large, the process may be difficult, and the processability and elongation rate may be reduced.

[0048] The poly(lactic acid-b-3-hydroxypropionic acid) block copolymer has a polydispersity index (PDI; Poly Dispersity Index) of 0.5 to 10.0, more specifically 0.5 or more, 1.0 or more, 2.0 or more, 3.0 or more, or 4.0 or more, and can be 10.0 or less, 8.0 or less, 6.0 or less, or 5.0 or less.

[0049] The method for producing the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition may include a step of polymerizing 3-hydroxypropionic acid to produce poly(3-hydroxypropionic acid); and a step of ring-opening polymerizing lactide to the poly(3-hydroxypropionic acid) to produce a poly(lactic acid-b-3-hydroxypropionic acid) block copolymer.

[0050] For example, the step of producing the poly(3-hydroxypropionic acid) may include a step of polymerizing 3-hydroxypropionic acid to produce poly(3-hydroxypropionic acid).

[0051] The reaction temperature of the polymerization can be 70°C to 120°C, 72°C or more, 74°C or more, 76°C or more, 78°C or more, or 80°C or more, and can be 115°C or less, 110°C or less, 105°C or less, 100°C or less, or 95°C or less. Also, the reaction pressure of the polymerization can be a pressure of 0.5 torr to 10 torr, for example, 0.6 torr or more, 0.7 torr or more, 0.8 torr or more, or 1.0 torr or more, and can be carried out at 9 torr or less, 8 torr or less, 7 torr or less, 6 torr or less, or 5 torr or less. Further, the reaction time of the polymerization can be appropriately considered in consideration of the molecular weight, yield, etc. of the produced 3-hydroxypropionic acid oligomer, and is preferably carried out for 1 hour to 30 hours, for example, 2 hours or more, 5 hours or more, 6 hours or more, 7 hours or more, or 8 hours or more, and can be carried out at 25 hours or less, 23 hours or less, 20 hours or less, 15 hours or less, or 10 hours or less.

[0052] The polymerization can be carried out in the presence of a sulfonic acid catalyst, and the sulfonic acid catalyst can be p-toluenesulfonic acid, m-xylene-4-sulfonic acid, 2-mesitylenesulfonic acid, or p-xylene-2-sulfonic acid. The catalyst can be used in an amount of 0.1 to 0.5 mol%, 0.15 to 0.4 mol%, or 0.2 to 0.3 mol% based on 3-hydroxypropionic acid.

[0053] The polymerization conditions can control the vinyl group content contained in the end groups of the produced poly(3-hydroxypropionic acid). For example, by adjusting the reaction temperature, reaction pressure, reaction time, catalyst usage amount, etc. of the polymerization, conditions such as lowering the polymerization reaction temperature, shortening the reaction time as much as possible, or using less catalyst can be controlled to lower the vinyl group content of poly(3-hydroxypropionic acid).

[0054] After producing the poly(3-hydroxypropionic acid), the poly(3-hydroxypropionic acid), lactide, and catalyst can be polymerized to produce a poly(lactic acid-b-3-hydroxypropionic acid) block copolymer.

[0055] Since the polymerization involves a ring-opening polymerization reaction of lactide, it can be carried out in the presence of a lactide ring-opening catalyst. As the catalyst used for the ring-opening polymerization, all catalysts generally used for the production of polylactic acid resin by the ring-opening polymerization reaction of lactide monomer can be used. For example, the ring-opening polymerization can be carried out under one or more catalysts selected from the group consisting of organometallic complex catalysts and organic catalysts. The organometallic complex catalyst can be used without limitation to its structure as long as it is generally used for the production of polylactic acid resin by the ring-opening polymerization reaction of lactide monomer. For example, the organometallic complex catalyst can be a catalyst represented by the following Chemical Formula 3. [Chemical Formula 3] MA 1 p A 2 2-p In the above Chemical Formula 3, M is Al, Mg, Zn, Ca, Sn, Fe, Y, Sm, Lu, Ti or Zr, p is an integer from 0 to 2, and A 1 and A 2 are each independently an alkoxy or carboxyl group.

[0056] More specifically, the catalyst can be tin(II) 2-ethylhexanoate (Sn(Oct)2; hereinafter also referred to as Tin Octoate).

[0057] On the other hand, the organic catalyst can be used without limitation of its constitution as long as it is generally used in the production of polylactic acid resin by the ring-opening polymerization reaction of lactide monomer. For example, the organic catalyst can be one or more selected from the group consisting of the following 1,5,7-triazabicyclo-[4,4,0]dec-5-ene (TBD), the following 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), the following 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD), the following 4-dimethylaminopyridine (DMAP), the following 4-(1-pyrrolidinyl)pyridine (PPY), imidazole, triazolium, thiourea, tertiary amine, and creatinine.

[0058] The content of the catalyst can be 0.0001 to 10 mol%, 0.005 to 8 mol%, 0.05 to 5 mol%, or 0.09 to 3 mol% based on 100 mol% of the lactide monomer. If the content of the catalyst based on 100 mol% of the lactide monomer is excessively low, the polymerization activity may not be sufficient. If the content of the catalyst is excessively high, the amount of residual catalyst in the produced block copolymer may increase, leading to decomposition of the copolymer or a decrease in molecular weight due to depolymerization such as transesterification reaction. Further, the ring-opening polymerization can be carried out at 150 to 200 °C for 5 minutes to 24 hours.

[0059] According to another embodiment of the present invention, a film containing the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition is provided.

[0060] The film containing the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition may have an average haze of less than 4.0, 3.8 or less, 3.6 or less, or 0.5 or more and 3.4 or less as measured by ASTM D1003. When the average haze of the film is excessively high, there is a problem that transparency does not appear. Further, the standard deviation between the positions of the haze values of the film may be 0.400 or less, 0.300 or less, or 0.100 or more and 0.200 or less.

[0061] Further, the film may have a thickness of 500 μm or less, for example, 10 μm or more, 30 μm or more, 50 μm or more, 70 μm or more, 90 μm or more, 100 μm or more, 120 μm or more, 140 μm or more, 150 μm or more, and may be 480 μm or less, 460 μm or less, 450 μm or less, 430 μm or less, 400 μm or less, 380 μm or less, 350 μm or less, 330 μm or less, 300 μm or less. Since the thickness of the film is within the above range, the elasticity becomes strong, the handleability is excellent, and the winding state and unwinding property of the roll can be improved. Further, the average haze measured by ASTM D1003 within such a thickness range can be less than 4.0.

Advantages of the Invention

[0062] It is possible to provide a poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition excellent in transparency according to the present invention and a film containing the same.

Brief Description of the Drawings

[0063]

Figure 1

Modes for Carrying Out the Invention

[0064] The invention will be described in more detail based on the following examples. However, the following examples are merely illustrative of the present invention, and the content of the present invention is not limited by the following examples.

[0065] Production Example 1: Production of Poly(3-hydroxypropionic acid) A 50 mL of a 60% aqueous solution of 3-hydroxypropionic acid was charged into a 100 mL Schlenk flask, and approximately 60% of the water in 3-hydroxypropionic acid was removed at 105 °C and 50 Torr for 2 hours in an oil bath. Then, 0.4 part by weight of p-toluenesulfonic acid (p-TSA) catalyst and 0.1 part by weight of tin(II) 2-ethylhexanoate were charged into the reaction flask based on 100 parts by weight of 3-hydroxypropionic acid, and melt polycondensation reaction was carried out at 80 °C and 1 Torr for 18 hours. After the reaction was completed, the reaction product was dissolved in chloroform at a ratio of 10 g / 50 mL, and then extracted with 500 mL of methanol to obtain poly(3-hydroxypropionic acid) A (ratio (content) of vinyl group in terminal group: 3 mol%; number average molecular weight: 10,000 g / mol, weight average molecular weight: 18,600 g / mol).

[0066] Production Example 2: Production of Poly(3-hydroxypropionic acid) B 50 mL of a 60% aqueous solution of 3-hydroxypropionic acid was charged into a 100 mL Schlenk flask, and approximately 40% of the water in 3-hydroxypropionic acid was removed at 105 °C and 50 Torr for 2 hours in an oil bath. 0.1 part by weight of p-toluenesulfonic acid (p-TSA) catalyst was charged into the reaction flask based on 100 parts by weight of 3-hydroxypropionic acid, and melt polycondensation reaction was carried out at 95 °C and 1 Torr for 24 hours. After the reaction was completed, the reaction product was dissolved in chloroform at a ratio of 10 g / 50 mL, and then extracted with 500 mL of methanol to obtain poly(3-hydroxypropionic acid) B (ratio (content) of vinyl group in terminal group: 10 mol%; number average molecular weight: 10,000 g / mol, weight average molecular weight: 17,600 g / mol).

[0067] Production Example 3: Production of Poly(3-hydroxypropionic acid) C 50 mL of a 60% aqueous solution of 3-hydroxypropionic acid was charged into a 100 mL Schlenk flask, and approximately 60% of the water in 3-hydroxypropionic acid was removed at 105 °C and 50 Torr for 2 hours using an oil bath. Then, 0.4 parts by weight of p-toluenesulfonic acid (p-TSA) catalyst was charged into the reaction flask based on 100 parts by weight of 3-hydroxypropionic acid, and a melt polycondensation reaction was carried out at 105 °C and 1 Torr for 8 hours. After the reaction was completed, the reaction product was dissolved in chloroform at a ratio of 10 g / 50 mL, and then extracted with 500 mL of methanol to obtain poly(3-hydroxypropionic acid) C (ratio (content) of vinyl groups in the end groups: 22 mol%; number average molecular weight: 10,000 g / mol, weight average molecular weight: 17,600 g / mol).

[0068] Production Example 4: Production of Poly(3-hydroxypropionic acid) D 50 mL of a 60% aqueous solution of 3-hydroxypropionic acid was charged into a 100 mL Schlenk flask, and approximately 60% of the water in 3-hydroxypropionic acid was removed at 105 °C and 50 Torr for 2 hours using an oil bath. Then, 0.2 parts by weight of p-toluenesulfonic acid (p-TSA) catalyst was charged into the reaction flask based on 100 parts by weight of 3-hydroxypropionic acid, and a melt polycondensation reaction was carried out at 95 °C and 1 Torr for 24 hours. After the reaction was completed, the reaction product was dissolved in chloroform at a ratio of 10 g / 50 mL, and then extracted with 500 mL of methanol to obtain poly(3-hydroxypropionic acid) D (ratio (content) of vinyl groups in the end groups: 30 mol%; number average molecular weight: 10,000 g / mol, weight average molecular weight: 21,100 g / mol).

[0069] Production Example 5: Production of Poly(3-hydroxypropionic acid) E Into a 100 ml Schlenk flask, 50 ml of a 60% aqueous solution of 3-hydroxypropionic acid was charged, and approximately 60% of the water in 3-hydroxypropionic acid was removed over 2 hours at 105 °C and 50 Torr in an oil bath. Then, 0.4 part by weight of p-toluenesulfonic acid (p-TSA) catalyst was charged into the reaction flask based on 100 parts by weight of 3-hydroxypropionic acid, and a melt polycondensation reaction was carried out at 95 °C and 1 Torr for 24 hours. After the reaction was completed, the reaction product was dissolved in chloroform at a ratio of 10 g / 50 mL, and then extracted with 500 mL of methanol to obtain poly(3-hydroxypropionic acid) E (ratio (content) of vinyl groups in the end groups: 44 mol%; number average molecular weight: 10,000 g / mol, weight average molecular weight: 16,400 g / mol).

[0070] Production Example 6: Production of poly(3-hydroxypropionic acid) F Into a 100 ml Schlenk flask, 50 ml of a 60% aqueous solution of 3-hydroxypropionic acid was charged, and approximately 60% of the water in 3-hydroxypropionic acid was removed over 2 hours at 05 °C and 50 Torr in an oil bath. Then, 0.4 part by weight of p-toluenesulfonic acid (p-TSA) catalyst was charged into the reaction flask based on 100 parts by weight of 3-hydroxypropionic acid, and a melt polycondensation reaction was carried out at 105 °C and 1 Torr for 24 hours. After the reaction was completed, the reaction product was dissolved in chloroform at a ratio of 10 g / 50 mL, and then extracted with 500 mL of methanol to obtain poly(3-hydroxypropionic acid) F (ratio (content) of vinyl groups in the end groups: 72 mol%; number average molecular weight: 10,000 g / mol, weight average molecular weight: 17,100 g / mol).

[0071] Example 1: Production of block copolymer Into a 100 ml Schlenk flask, 20 g of lactide, 2 g of poly(3-hydroxypropionic acid) A produced in Production Example 1, and 0.009 mL of tin(II) 2-ethylhexanoate were charged, and vacuum drying was carried out at a temperature of 40 °C and 1 Torr for 5 hours. Then, the mixture was charged into an oil bath pre-heated to 180 °C and subjected to a polymerization reaction for 1 hour and 30 minutes to produce a poly(lactic acid-b-3-hydroxypropionic acid) block copolymer (weight average molecular weight: 128,600 g / mol, number average molecular weight: 50,700 g / mol, polydispersity index (PDI): 2.5). Also, the block copolymer was recovered in an oil bath and devolatilized at 140 °C and a reduced pressure of 1 to 5 Torr for 3 hours to remove the monomers.

[0072] Example 2: Production of Block Copolymer

[0073] A poly(lactic acid-b-3-hydroxypropionic acid) block copolymer (weight average molecular weight: 95,500 g / mol, number average molecular weight: 31,100 g / mol, polydispersity index (PDI): 3.1) was produced in the same manner as in Example 1, except that poly(3-hydroxypropionic acid) B produced in Production Example 2 was used instead of poly(3-hydroxypropionic acid) A.

[0074] Example 3: Production of Block Copolymer A poly(lactic acid-b-3-hydroxypropionic acid) block copolymer (weight average molecular weight: 87,100 g / mol, number average molecular weight: 31,200 g / mol, polydispersity index (PDI): 2.8) was produced in the same manner as in Example 1, except that 4 g of poly(3-hydroxypropionic acid) B produced in Production Example 2 was used instead of 2 g of poly(3-hydroxypropionic acid) A.

[0075] Example 4: Production of Block Copolymer A poly(lactic acid-b-3-hydroxypropionic acid) block copolymer (weight average molecular weight: 119,800 g / mol, number average molecular weight: 44,440 g / mol, polydispersity index (PDI): 2.7) was produced in the same manner as in Example 1, except that poly(3-hydroxypropionic acid) C produced in Production Example 3 was used instead of the poly(3-hydroxypropionic acid) A.

[0076] Example 5: Production of Block Copolymer A poly(lactic acid-b-3-hydroxypropionic acid) block copolymer (weight average molecular weight: 115,200 g / mol, number average molecular weight: 37,200 g / mol, polydispersity index (PDI): 3.1) was produced in the same manner as in Example 1, except that poly(3-hydroxypropionic acid) D produced in Production Example 4 was used instead of the poly(3-hydroxypropionic acid) A.

[0077] Comparative Example 1: Production of Block Copolymer A poly(lactic acid-b-3-hydroxypropionic acid) block copolymer (weight average molecular weight: 103,400 g / mol, number average molecular weight: 42,600 g / mol, polydispersity index (PDI): 2.4) was produced in the same manner as in Example 1, except that poly(3-hydroxypropionic acid) E produced in Production Example 5 was used instead of the poly(3-hydroxypropionic acid) A.

[0078] Comparative Example 2: Production of Block Copolymer A poly(lactic acid-b-3-hydroxypropionic acid) block copolymer (weight average molecular weight: 113,800 g / mol, number average molecular weight: 31,900 g / mol, polydispersity index (PDI): 3.6) was produced in the same manner as in Example 1, except that poly(3-hydroxypropionic acid) F produced in Production Example 6 was used instead of the poly(3-hydroxypropionic acid) A.

[0079] Comparative Example 3: Production of Polymer Blend (1) Production of Poly(lactic acid) 20 g of lactide, 2 μl of 1 - Octanol, and 0.002 mL of tin(II) 2 - ethylhexanoate were charged into a 100 - ml Schlenk flask, and vacuum - dried at 40 °C and 1 Torr for 5 hours. Then, the mixture was charged into an oil bath pre - heated to 180 °C and subjected to a polymerization reaction for 1 hour and 30 minutes to produce polylactic acid (weight - average molecular weight: 18,000 g / mol). Also, the block copolymer was recovered in the oil bath and devolatilized at 140 °C and a reduced pressure of 1 - 5 Torr for 3 hours to remove the monomers. (2) Preparation of polymer blend 100 wt% of the polylactic acid and 5 wt% of poly(3 - hydroxypropionic acid) B produced in Production Example 2 were charged into a screw extruder (Thermo scientific, MiniCTW), and extruded and mixed at 190 °C to produce a polymer blend.

[0080] Comparative Example 4: Preparation of polymer blend A polymer blend was produced in the same manner as in Comparative Example 3, except that 10 wt% of poly(3 - hydroxypropionic acid) B was used instead of 5 wt% of poly(3 - hydroxypropionic acid) B.

[0081] Evaluation 1. Analysis by gel permeation chromatography (GPC) The products obtained from the above Examples and Comparative Examples were analyzed by GPC to measure the molecular weight of the block copolymer and shown in Table 1 below. Also, the products were analyzed by GPC - IR to measure the content of poly(3 - hydroxypropionic acid) contained in the products, and the results are shown as "P3HP content X" in Table 1 below.

[0082] <GPC analysis conditions> The product was dissolved in chloroform to a concentration of 2 mg / ml, and then 20 μl was injected into GPC for GPC analysis at 40°C. At this time, chloroform was used as the mobile phase of GPC, flowing in at a flow rate of 1.0 mL / min. Two Agilent Mixed-B columns were connected in series and used, and an RI detector (RI Detector) was used as the detector. The Mw value was derived using a calibration curve formed using polystyrene standard specimens. The weight-average molecular weights of the polystyrene standard specimens were 12 kinds, namely 162 g / mol, 580 g / mol, 1,180 g / mol, 4,870 g / mol, 9,310 g / mol, 17,120 g / mol, 75,050 g / mol, 200,500 g / mol, 448,500 g / mol, 10,690,000 g / mol, 3,022,000 g / mol, and 6,545,000 g / mol.

[0083] 2. Analysis of Nuclear Magnetic Resonance (NMR) The products obtained from the above Examples and Comparative Examples were analyzed by NMR to measure the total content of "poly(3-hydroxypropionic acid)" contained in the product and "poly(3-hydroxypropionic acid) block" contained in the block copolymer, and the results are shown as "Total P(3HP) content (X + Y)" in Table 1 below. On the other hand, the content of "poly(3-hydroxypropionic acid) block" was calculated as the difference between the above "Total P(3HP) content (X + Y)" and "P(3HP) content X", and the results are shown as "P(3HP) block content Y)" in Table 1 below.

[0084] <NMR Analysis Conditions> Sample pretreatment: After dissolving 10 mg of the sample in 1 mL of chloroform, it was applied to the analysis. 1 H Solution NMR Pulse program: zg30 Ns: 16 d1: 10 sec Temperature: 298K

[0085] 3. Measurement of haze The products obtained from the above Examples and Comparative Examples were used to produce films with a thickness of 0.3 T (300 μm) using a hot press. The haze values of the films were measured by the ASTM D1003 method by collecting SPL at the center part of the starting points of 0 m, 200 m, 400 m, 600 m, 800 m, and 1000 m of each roll using a haze meter (NDH5000W of Nippon Denshoku Co., Ltd.), and the average value and standard deviation were obtained and shown in Table 1 below.

Table 1

[0086] According to Table 1 above, in Examples 1 to 5, the content (X) of poly(3-hydroxypropionic acid) contained in the composition was 3.0 to 7.0% by weight, and it was confirmed that the average haze of the films produced thereby was 3.7 or less and the transparency characteristics were excellent. On the other hand, in Comparative Examples 1 and 2, the content (X) of poly(3-hydroxypropionic acid) contained in the composition was 7.7% by weight and 9.0% by weight, respectively, and it was confirmed that the average haze of the films produced therefrom was 4.0 or more and the transparency characteristics were inferior to those of the Examples.

[0087] Also, it was confirmed that the films produced from the compositions of Comparative Examples 3 and 4, which are polymer blends, had a significantly high haze of 5.3 or more. In the case of Comparative Example 4 where the content (X) of poly(3-hydroxypropionic acid) was 10.0% by weight, it was confirmed that the average haze was 31.2 and the opacity was high.

Claims

1. A poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition containing a poly(lactic acid-b-3-hydroxypropionic acid) block copolymer and poly(3-hydroxypropionic acid), wherein the average haze measured by ASTM D1003 is less than 4.

0. A poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition.

2. The poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition according to Claim 1, wherein the poly(3-hydroxypropionic acid) is contained in an amount of more than 0% by weight and 7.0% by weight or less based on 100% by weight of the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition.

3. The poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition according to Claim 1, wherein the poly(3-hydroxypropionic acid) is contained in an amount of 3.0% by weight or more and 6.0% by weight or less based on 100% by weight of the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition.

4. The poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition according to Claim 1, wherein the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer is a block copolymer obtained by ring-opening polymerization of lactide with poly(3-hydroxypropionic acid).

5. The poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition according to Claim 1 or 4, wherein the ratio of vinyl groups in the terminal groups of the poly(3-hydroxypropionic acid) is 40 mol% or less.

6. The poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition according to Claim 1 or 4, wherein the poly(3-hydroxypropionic acid) has a number average molecular weight of 5,000 or more and 300,000 or less.

7. The poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition according to Claim 1, wherein the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer is represented by the following Chemical Formula 1. 【Chemical 1】 (In the following Chemical Formula 1, m is an integer of 100 to 1000, n is an integer of 500 to 4000.)

8. The poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition according to Claim 1, wherein the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer has a weight average molecular weight of 50,000 or more and 600,000 or less.

9. The poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition according to claim 1, wherein the UV transmittance is 80% or more.

10. A film comprising the poly(lactic acid-b-3-hydroxypropionic acid) block copolymer composition according to claim 1.

11. The film according to claim 10, wherein the average haze measured by ASTM D1003 is less than 4.

0.

12. The film according to claim 11, wherein the standard deviation between the positions of the haze values is 0.400 or less.

13. The film according to claim 10, wherein the thickness is 500 μm or less.

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