Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
  • C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
  • C08G63/60—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from the reaction of a mixture of hydroxy carboxylic acids, polycarboxylic acids and polyhydroxy compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G2230/00—Compositions for preparing biodegradable polymers

Definitions

• the present invention relates to a block copolymer that has excellent biodegradability, hydrolysis resistance, and tensile properties.
• polylactic acid a bioplastic
• Polylactic acid is made from plant-derived renewable resources such as corn produced through photosynthesis, and is expected to be used in a wide range of fields.
• polylactic acid is more brittle than petroleum-based plastics, has inferior viscosity, flexibility, impact resistance, heat resistance, etc., and is more easily hydrolyzed. Therefore, the use of polylactic acid as a resin material may be limited.
• technologies related to resin compositions or molded products thereof in which polyester and polylactic acid are copolymerized using monomers having a specific number of carbon atoms are being considered (for example, patent documents (See 1 to 3).
• the resins or resin compositions containing polylactic acid described in Patent Documents 1 to 5 have some degree of biodegradability.
• biodegradability refers to the property of being eventually decomposed into water and carbon dioxide by organisms such as microorganisms, and resins containing polylactic acid are known to exhibit biodegradability in compost. .
• final products made of resin materials are required to have hydrolysis resistance in order to suppress the progress of aging deterioration. Therefore, bioplastics need to have both biodegradability and hydrolysis resistance depending on the application.
• tear strength is investigated as a mechanical property of a resin composition, but there is no description regarding tensile properties. From the viewpoint of versatility of the resin composition, a resin composition having excellent tensile properties is desired.
• an object of the present invention is to provide a block copolymer that has excellent biodegradability, hydrolysis resistance, and tensile properties in activated sludge and compost.
• the present invention is as follows.
• the polyester unit (b) contains a unit derived from an aliphatic diol (b1) and an aliphatic dicarboxylic acid (b2), and the aliphatic diol (b1) has 4 or more carbon atoms having an alkyl group as a branched chain.
• the content of the block structural unit (A) is 5% by mass or more and 95% by mass or less, based on the total of 100% by mass of the block structural unit (A) and the block structural unit (B). 1].
• [3] The block copolymer according to [1] or [2] above, wherein the aliphatic dicarboxylic acid (b2) has 4 or more and 12 or less carbon atoms.
• [4] The block copolymer according to any one of [1] to [3] above, wherein the aliphatic diol (b1) has 10 or less carbon atoms.
• polylactic acid unit means “a structural unit derived from polylactic acid”
• polyyester unit means “a structural unit derived from polyester”.
• main chain of a polymer means the longest molecular chain in the polymer molecule, unless otherwise specified.
• branched chain means a molecular chain other than the main chain in a molecule.
• the block copolymer of this embodiment includes a block structural unit (A) containing a polylactic acid unit (a) as a main component and a block structural unit (B) containing a polyester unit (b) as a main component,
• the number average molecular weight of the structural unit (B) is 30,000 or more and less than 200,000.
• the present inventors have conducted various studies on formulations for imparting a wide range of biodegradability, excellent hydrolysis resistance, and tensile properties to block copolymers. As a result, the present inventors found that the inclusion of block structural units (A) and block structural units (B) has biodegradability not only in compost but also in activated sludge, and achieves excellent hydrolysis resistance. We have found that this is an effective prescription for In addition, it has been found that if the number average molecular weight of the block structural unit (B) is within a specific numerical range, the tensile properties are also excellent.
• the polyester unit (b) contains a unit derived from an aliphatic diol (b1) and an aliphatic dicarboxylic acid (b2), and the aliphatic diol (b1) has a carbon number of 4 or more and has an alkyl group as a branched chain. It is characterized by being a group diol. Due to the above characteristics, the block structural unit (B) tends to become an amorphous polymer, so it is assumed that microorganisms can easily enter the polymer structure during biodegradation, resulting in excellent biodegradability over a wide range. Moreover, it is thought that hydrolysis resistance is improved because the aliphatic diol (b1) has an alkyl group as a branched chain.
• the block structural unit (B) is not an amorphous polymer, it is thought that microorganisms will have difficulty in penetrating the polymer structure, making it difficult to biodegrade it, making it impossible to obtain the effects of the present invention.
• being an amorphous polymer is only one factor that affects biodegradability and hydrolyzability. Biodegradation and hydrolysis are thought to be caused by a combination of various factors, including whether microorganisms recognize amorphous structures as food, whether they are easily accessible to enzymes and microorganisms, steric hindrance of the main chain, melting point, and degree of crystallinity. It's for a reason.
• the block structural unit (A) has a polylactic acid unit (a) as a main component.
• the above-mentioned “main component” means the unit with the highest content rate among the units constituting the block structural unit (A).
• the above-mentioned “main component” is a unit having the highest content in terms of mass percentage among the units constituting the block structural unit (A).
• the content ratio of the polylactic acid unit (a) in the block structural unit (A) is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 85% by mass or more, even more preferably 90% by mass or more. and may contain 100% by mass. Further, there is no upper limit to the amount of polylactic acid units (a) contained in the block structural unit (A), and is, for example, 100% by mass or less.
• the polylactic acid constituting the polylactic acid unit (a) may be prepared by a direct condensation method of lactic acid, or may be prepared by a ring-opening polymerization method of lactide.
• lactic acid for example, at least one selected from the group consisting of L-lactic acid, D-lactic acid, and DL-lactic acid can be used.
• lactide for example, at least one selected from the group consisting of L-lactide, D-lactide, DL-lactide, and meso-lactide can be used.
• polylactic acid poly-L-lactic acid, poly-D-lactic acid, poly-DL-lactic acid, and stereocomplex polylactic acid obtained by mixing poly-L-lactic acid and poly-D-lactic acid can be used.
• polylactic acid is preferably poly-L-lactic acid, poly-D-lactic acid, or poly-DL-lactic acid; Lactic acid is more preferred.
• the polylactic acid is not a stereocomplex polylactic acid.
• the block structural unit (A) preferably contains 70% by mass of structural units derived from poly-L-lactic acid or poly-D-lactic acid.
• the content is more preferably 80% by mass or more, still more preferably 90% by mass or more.
• the block structural unit (A) is composed of a structural unit derived from poly-L-lactic acid or a structural unit derived from poly-D-lactic acid, that is, a structural unit derived from poly-L-lactic acid or a structural unit derived from poly-D-lactic acid.
• An example of a preferred embodiment is that the constituent units are 100% by mass.
• the block structural unit (A) may or may not contain a unit (a') other than the polylactic acid unit (a).
• the monomer constituting the unit (a') is not particularly limited as long as it does not impair the effects of the present invention.
• the content of the unit (a') in the block structural unit (A) is preferably 30% by mass or less, more preferably 20% by mass or less, still more preferably 15% by mass or less, even more preferably 10% by mass or less. be.
• the number average molecular weight of the block structural unit (A) is preferably 5,000 to 150,000, more preferably 10,000 to 100,000, and even more preferably 20,000 to 40,000. Within the above numerical range, even more excellent hydrolysis resistance can be exhibited.
• the number average molecular weight of the block structural units (A) means the total of all blocks.
• the number average molecular weight of the block structural unit (A) can be determined from the number average molecular weight of the block copolymer described below and the mass content of the block structural unit (A).
• the number average molecular weight of the block structural unit (A) can be changed, for example, by adjusting the polymerization conditions of polylactic acid.
• the block structural unit (B) has a polyester unit (b) as a main component.
• the above-mentioned “main component” means the unit with the highest content rate among the units constituting the block structural unit (B).
• the above-mentioned “main component” is a unit having the highest content ratio in terms of mass percentage among the units constituting the block structural unit (B).
• the content ratio of the polyester unit (b) in the block structural unit (B) is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, even more preferably 85% by mass or more, Particularly preferably, the content is 90% by mass or more, and may be 100% by mass.
• the polyester unit (b) contains units derived from an aliphatic diol (b1) and an aliphatic dicarboxylic acid (b2). Specifically, the polyester unit (b) contains a unit derived from a polyester obtained by reacting an aliphatic diol (b1) and an aliphatic dicarboxylic acid (b2). The polyester unit (b) may or may not contain a unit derived from a monomer other than the aliphatic diol (b1) and the aliphatic dicarboxylic acid (b2).
• Monomers other than the aliphatic diol (b1) and the aliphatic dicarboxylic acid (b2) are not particularly limited as long as they do not impair the effects of the present invention.
• the total amount of aliphatic diol (b1) and aliphatic dicarboxylic acid (b2) in polyester unit (b) is preferably 90 mol% or more, more preferably 95 mol% or more, even more preferably 99 mol% or more, and 100 mol%. It may be %.
• the aliphatic diol (b1) is an aliphatic diol having 4 or more carbon atoms and having an alkyl group as a branched chain. Aliphatic diols have two hydroxyl groups. Geminal diols are usually excluded from aliphatic diols (b1). Preferably, the two hydroxyl groups of the aliphatic diol (b1) are primary hydroxyl groups. "Primary hydroxyl group” refers to a hydroxyl group bonded to a primary atom, preferably a primary carbon atom.
• the said "carbon number” is the carbon number of the whole aliphatic diol (b1) including the carbon number which forms the said alkyl group.
• the "branched chain” in the aliphatic diol (b1) refers to a partial structure branched from the “main chain” in the aliphatic diol (b1), and preferably no hydroxyl group is bonded to the terminal thereof.
• the "main chain” in the aliphatic diol (b1) is a molecular chain composed of a plurality of carbon atoms connecting the two primary hydroxyl groups with the two primary hydroxyl groups in the molecule at both ends. Preferably, it refers to a substructure.
• the aliphatic diol (b1) preferably has hydroxyl groups at both ends of the main chain. This makes it possible to easily produce a triblock copolymer that easily reacts with dicarboxylic acids, and to obtain a block copolymer that is even more excellent in biodegradability and hydrolysis resistance.
• the number of carbon atoms in the aliphatic diol (b1) is 3 or less, the hydrolysis resistance may be poor.
• the number of carbon atoms in the aliphatic diol (b1) is preferably 5 or more, more preferably 6 or more. Furthermore, from the viewpoint of biodegradability, the number of carbon atoms in the aliphatic diol (b1) is preferably 10 or less, more preferably 9 or less.
• the number of carbon atoms in the main chain of the aliphatic diol (b1) depends on the number of carbon atoms in the branched chain, but is preferably 2 or more, more preferably 3 or more, still more preferably 4 or more, and even more preferably 5. or more, and preferably 9 or less, more preferably 8 or less.
• the number of branched chains is preferably one or two, more preferably one.
• the branched chain is preferably at least one of a methyl group, an ethyl group, and a propyl group, more preferably at least one of a methyl group and an ethyl group, and even more preferably a methyl group.
• each branched chain may be the same or different.
• Aliphatic diol (b1) is, for example, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-1,3-propanediol, 2-ethyl-2 -Methyl-1,3-propanediol, 2-methyl-1,4-butanediol, 1,2-pentanediol, 1,3-pentanediol, 2,3-pentanediol, 2,4-pentanediol, 2 -Methyl-2,4-pentanediol, 1,4-pentanediol, 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2-ethyl-1,5-pentanediol, 2,4-dimethyl-1,5-pent
• the aliphatic diol (b1) is preferably at least one of 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol and 2,4-diethyl-1,5-pentanediol. , more preferably 3-methyl-1,5-pentanediol.
• One type of aliphatic diol (b1) may be used alone, or two or more types may be used in combination.
• the number of carbon atoms in the aliphatic dicarboxylic acid (b2) is not limited as long as the effects of the present invention are not impaired.
• the number of carbon atoms in the aliphatic dicarboxylic acid (b2) is preferably 4 or more, more preferably 5 or more, and still more preferably 6 or more.
• the number of carbon atoms in the aliphatic dicarboxylic acid (b2) is preferably 12 or less, more preferably 10 or less, and even more preferably 8 or less.
• Examples of the aliphatic dicarboxylic acid (b2) include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, and decanedicarboxylic acid. Preferred are succinic acid, adipic acid, and sebacic acid, and more preferred is adipic acid.
• the aliphatic dicarboxylic acids (b2) may be used alone or in combination of two or more.
• a combination of acids and a combination of 2,4-diethyl-1,5-pentanediol and adipic acid are examples of preferred embodiments, a combination of 3-methyl-1,5-pentanediol and succinic acid, a combination of 2,4-diethyl-1,5-pentanediol and succinic acid, - A combination of diethyl-1,5-pentanediol and succinic acid, a combination of 3-methyl-1,5-pentanediol and adipic acid, and a combination of 2,4-diethyl-1,5-pentanediol and adipic acid.
• the charging molar ratio [aliphatic diol (b1)/aliphatic dicarboxylic acid (b2)] when aliphatic diol (b1) and aliphatic dicarboxylic acid (b2) are reacted is preferably 1.4/1 to 1.4/1. It is 1/1.4, more preferably 1.2/1 to 1/1.2.
• the block structural unit (B) may or may not contain a unit (b') other than the polyester unit (b).
• the monomer constituting the unit (b') is not particularly limited as long as it does not impair the effects of the present invention.
• the content of the unit (b') in the block structural unit (B) is preferably 50% by mass or less, more preferably 30% by mass or less, still more preferably 20% by mass or less, even more preferably 15% by mass or less, Particularly preferably, it is 10% by mass or less.
• the number average molecular weight of the block structural unit (B) is 30,000 or more and less than 200,000. If the number average molecular weight of the block structural unit (B) is less than 30,000, the tensile properties will be poor. When the number average molecular weight of the block structural unit (B) is 200,000 or more, synthesis becomes difficult and there is also a possibility that manufacturing cost increases. From the viewpoint of developing even better tensile properties, the number average molecular weight of the block structural unit (B) is preferably 33,000 or more, more preferably 36,000 or more.
• the number average molecular weight of the block structural unit (B) is preferably less than 180,000, more preferably less than 150,000, even more preferably less than 120,000, and even more preferably less than 100,000. It may be less than or equal to 70,000.
• the number average molecular weight of the block structural unit (B) can be determined by gel permeation chromatography (GPC), and specifically can be measured by the method described in Examples. Further, the number average molecular weight of the block structural unit (B) can also be determined from the number average molecular weight of the block copolymer described below and the mass content of the block structural unit (B).
• the number average molecular weight of the block structural unit (B) can be changed, for example, by adjusting the polymerization conditions of the aliphatic diol (b1) and the aliphatic dicarboxylic acid (b2).
• the content of the block structural unit (A) is preferably 5% by mass or more and 95% by mass or less with respect to a total of 100% by mass of the block structural unit (A) and the block structural unit (B).
• the proportion of the block structural unit (A) is 5% by mass or more, the block copolymer tends to have better strength and handling properties.
• the proportion of the block structural unit (A) is 95% by mass or less, the block copolymer tends to have excellent flexibility, impact resistance, and biodegradability, and has even better tensile properties.
• the proportion of the block structural unit (A) is more preferably 10% by mass or more, and still more preferably 15% by mass or more.
• the proportion of the block structural unit (A) is more preferably 80% by mass or less, still more preferably 75% by mass or less, even more preferably 70% by mass or less, and even more preferably Preferably it is 60% by mass or less.
• the proportion of block structural units (A) can be determined by 1 H-NMR, and specifically can be measured by the method described in Examples.
• the total content ratio of block structural units (A) and block structural units (B) in the block copolymer is preferably 90% by mass or more, even more preferably 95% by mass or more, and 100% by mass. There may be. Further, there is no upper limit to the total content ratio of block structural units (A) and block structural units (B) in the block copolymer, and is, for example, 100% by mass or less.
• the block copolymer may or may not contain units other than the block structural unit (A) and the block structural unit (B). Units other than the block structural unit (A) and the block structural unit (B) are not particularly limited as long as they do not impair the effects of the present invention.
• the content of units other than the block structural unit (A) and block structural unit (B) in the block copolymer is preferably 10% by mass or less, more preferably 5% by mass or less.
• the number average molecular weight of the block copolymer is not limited as long as the condition that the number average molecular weight of the block structural unit (B) is 30,000 or more and less than 200,000 is satisfied.
• the number average molecular weight of the block copolymer may be, for example, 35,000 or more, or 40,000 or more.
• the number average molecular weight of the block copolymer is preferably 45,000 or more, 50,000 or more, or 55,000 or more, more preferably more than 58,000, and even more preferably 60,000 or more, and may be 65,000 or more, 70,000 or more, 75,000 or more, 80,000 or more, or 81,000 or more.
• the number average molecular weight of the block copolymer is preferably 450,000 or less, more preferably 350,000 or less, even more preferably 250,000 or less, even more preferably 200, 000 or less, more preferably 150,000 or less, and may be 110,000 or less or 100,000 or less.
• the number average molecular weight of the block copolymer can be determined by gel permeation chromatography (GPC), and specifically can be measured by the method described in Examples.
• the number average molecular weight of the block copolymer can be adjusted by, for example, the number average molecular weight of the block structural unit (A), the number average molecular weight of the block structural unit (B), and the number of each block structural unit.
• the binding type of the block copolymer is preferably a triblock type or a diblock type, and more preferably a triblock type.
• the block copolymer may be a mixture of triblock type and diblock type.
• the bond format is preferably [block structural unit (A)]-[block structural unit (B)]-[block structural unit (A)].
• the glass transition temperature of the block copolymer is preferably -80°C or more and -15°C or less. Within the above numerical range, the block copolymer tends to have excellent flexibility and impact resistance. From the viewpoint of low-temperature properties such as impact resistance at low temperatures, the glass transition temperature of the block copolymer is more preferably -20°C or lower, even more preferably -25°C or lower, and even if it is -30°C or lower. The temperature may be -40°C or lower, or -50°C or lower.
• the lower limit of the glass transition temperature of the block copolymer is preferably lower, but may be, for example, -75°C or higher, -70°C or higher, or -65°C.
• the glass transition temperature of the block copolymer can be determined by scanning calorimetry, and specifically can be determined by the method described in Examples.
• the elongation at break of the block copolymer is not particularly limited, but is preferably 60% or more, more preferably 100% or more, even more preferably 150% or more, even more preferably 300% or more, particularly preferably 500% or more, Most preferably it is 600% or more.
• the elongation at break can be measured, for example, by the method described in Examples based on JIS K7161-1:2014.
• the hydrolysis resistance of a block copolymer can be determined by, for example, dissolving it in chloroform at a concentration of 10% by mass, pouring it onto a glass plate to make a film with a thickness of 200 ⁇ m, and cutting it out to a weight of 0.15 g.
• the test sample is immersed in 50 mL of ion-exchanged water with a pH of 7, left at 50°C, and the number average molecular weight is measured at predetermined intervals to measure the time when the number average molecular weight becomes less than 90% of the initial number average molecular weight. It can be evaluated by the method described in the example.
• the time required for the initial number average molecular weight to be less than 90% is preferably 50 hours or more, more preferably 100 hours or more, even more preferably 150 hours or more, Even more preferably 200 hours or more, particularly preferably 250 hours or more, and most preferably more than 400 hours.
• the hydrolysis resistance of the block copolymer is within the above range, for example, a product with excellent long-term reliability of mechanical properties can be manufactured using the block copolymer.
• Biodegradability of block copolymer in compost The biodegradability of the block copolymer in compost can be measured, for example, by the method described in Examples based on ISO 14855-2:2018. There is no particular limitation on the biodegradability of the block copolymer in compost, but the decomposition rate after 15 days is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably It is 20% by mass or more. When the biodegradability of the block copolymer in compost is within the above range, for example, a product with excellent compost biodegradability and low environmental impact can be manufactured using the block copolymer.
• Biodegradability of block copolymer in activated sludge The biodegradability of the block copolymer in activated sludge can be measured, for example, by the method described in Examples, which is based on the method according to ISO 14851:2019. Although there is no particular limitation on the biodegradability of the block copolymer in activated sludge, the decomposition rate after 90 days is preferably 5% by mass or more. If the biodegradability of the block copolymer in activated sludge is within the above range, for example, the block copolymer can be used to manufacture products with excellent biodegradability and low environmental impact in wastewater treatment facilities. .
• a known method for producing a block copolymer may be, for example, a method in which a polyester constituting the polyester unit (b) is synthesized, and the polyester and lactide are subjected to a polymerization reaction.
• the above polyester can be synthesized by a known method.
• a polyester can be synthesized by reacting an aliphatic diol (b1) and an aliphatic dicarboxylic acid (b2) using an esterification catalyst (eg, tin octylate, tin chloride, tin oxide).
• a ring-opening polymerization catalyst for example, tin octylate, tin chloride, tin oxide.
• the polymerization reaction include solution polymerization, melt polymerization, interfacial polycondensation, etc., and known polymerization reaction conditions can be set for any of them.
• a known method for producing a block copolymer includes, for example, synthesizing polylactic acid constituting the polylactic acid unit (a) and polyester constituting the polyester unit (b), and A method may also be used in which the polyester is reacted with the polyester.
• Polylactic acid can be synthesized by a known method.
• polylactic acid may be synthesized by reacting lactic acid using a direct condensation method, or polylactic acid may be synthesized by reacting lactide using a ring-opening polymerization method.
• an esterification catalyst for example, tin octylate, tin chloride, tin oxide.
• the polymerization reaction include solution polymerization, melt polymerization, interfacial polycondensation, etc., and known polymerization reaction conditions can be set for any of them.
• the physical properties of the block copolymers in Examples and Comparative Examples were measured or evaluated by the following methods.
• Mn Number average molecular weight
• Mn of the block copolymer was determined in terms of standard polystyrene by gel permeation chromatography (GPC).
• Mn of the block structural unit (B) was determined from Mn of the block copolymer and the mass content of the block structural unit (B).
• Biodegradability (compost) Biodegradability in compost was measured according to a method according to ISO 14855-2:2018. A if the decomposition rate after 15 days is 20% by mass or more, B if it is 10% by mass or more and less than 20% by mass, C if it is 5% by mass or more and less than 10% by mass, and C if it is less than 5% by mass.
• A if the decomposition rate after 15 days is 20% by mass or more
• B if it is 10% by mass or more and less than 20% by mass
• C if it is 5% by mass or more and less than 10% by mass
• C if it is less than 5% by mass.
• Biodegradability in activated sludge was measured according to a method according to ISO 14851:2019. If the decomposition rate after 90 days was 5% by mass or more, it was evaluated as A, and if it was less than 5% by mass, it was evaluated as B.
• Elongation at break Test pieces were prepared using the block copolymers obtained in Examples and Comparative Examples, and measurements were performed in accordance with JIS K7161-1:2014. The test piece was used by annealing a 100 ⁇ m thick press sheet at 110° C. for 3 hours and punching it into a No. 3 dumbbell shape. The tensile speed was 5 mm/min.
• the structural unit (B' ) was synthesized.
• the pressure was returned to normal, the temperature was cooled to 80°C, and toluene was added to dilute the solid content to 40% by mass, and the above toluene solution was poured into methanol in an amount twice the total amount of the solution. The supernatant liquid was discarded, and the same amount of methanol as the amount of the toluene solution was added again for washing.
• a toluene solution of a block copolymer consisting of a unit (A) and a block structural unit (B) whose main component is a polyester unit (b) was obtained.
• Toluene was added to this solution to dilute the solid content concentration to 30% by mass, and then the above-mentioned toluene solution was poured into methanol in an amount twice the total amount of the solution to precipitate a solid. The supernatant methanol was discarded, and the same amount of methanol as the amount of the toluene solution was added again for washing.
• a block copolymer consisting of a block structural unit (B) having as a main component was obtained. According to 1 H-NMR measurement of the obtained block copolymer, the peak derived from methylene adjacent to both hydroxyl terminals of the polymer consisting of the structural unit (B') disappeared, and [block structural unit (A)]-[ It was confirmed that a triblock consisting of a structure of [block structural unit (B)]-[block structural unit (A)] was mainly produced. The above-mentioned measurements and evaluations were performed on the obtained block copolymer. The results are shown in Table 1-1. The obtained block copolymer had good biodegradability, hydrolysis resistance, and elongation at break.
• Example 2 The number average molecular weight was adjusted by adjusting the reaction time during the synthesis of a polymer consisting of a structural unit (B') whose main component is a polyester unit, the mass ratio of L-lactide used was changed, and the synthesis time The same procedure as in Example 1 was carried out except that the dilution concentration of the dilution was appropriately changed to a concentration that was easy to handle. A block copolymer consisting of the block structural unit (B) was obtained. The above-mentioned measurements and evaluations were performed on the obtained block copolymer. The results are shown in Table 1-1. The obtained block copolymer had good biodegradability, hydrolysis resistance, and elongation at break.
• Example 4 The use of 2-methyl-1,3-propanediol instead of 3-methyl-1,5-pentanediol, the use of succinic acid instead of adipic acid, and the structural units mainly composed of polyester units ( The number average molecular weight was adjusted by adjusting the reaction time during synthesis of the polymer consisting of B'), the mass ratio of L-lactide used was changed, and the dilution concentration during synthesis was appropriately changed to a concentration that was easy to handle.
• a block was prepared in the same manner as in Example 1, consisting of a block structural unit (A) containing a polylactic acid unit (a) as a main component and a block structural unit (B) containing a polyester unit (b) as a main component.
• a polymer was obtained.
• the above-mentioned measurements and evaluations were performed on the obtained block copolymer. The results are shown in Table 1-1.
• the obtained block copolymer had good biodegradability, hydrolysis resistance, and elongation at break.
• Example 5 2,4-diethyl-1,5-pentanediol was used instead of 3-methyl-1,5-pentanediol, and during the synthesis of a polymer consisting of structural units (B') mainly composed of polyester units.
• the procedure was the same as in Example 1, except that the number average molecular weight was adjusted by adjusting the reaction time, the mass ratio of L-lactide used was changed, and the dilution concentration during synthesis was appropriately changed to a concentration that was easy to handle.
• a block copolymer consisting of a block structural unit (A) containing a polylactic acid unit (a) as a main component and a block structural unit (B) containing a polyester unit (b) as a main component was obtained.
• the above-mentioned measurements and evaluations were performed on the obtained block copolymer. The results are shown in Table 1-1.
• the obtained block copolymer had good biodegradability, hydrolysis resistance, and elongation at break.
• Example 6 The use of 2-methyl-1,3-propanediol instead of 3-methyl-1,5-pentanediol, and the reaction time during the synthesis of a polymer consisting of structural units (B') mainly composed of polyester units.
• a block structural unit containing polylactic acid unit (a) as the main component was prepared in the same manner as in Example 1, except that the number average molecular weight was adjusted by adjusting , and the dilution concentration during synthesis was appropriately changed to a concentration that was easy to handle.
• a block copolymer consisting of (A) and a block structural unit (B) whose main component is a polyester unit (b) was obtained. The above-mentioned measurements and evaluations were performed on the obtained block copolymer. The results are shown in Table 1-1.
• the obtained block copolymer had good biodegradability, hydrolysis resistance, and elongation at break.
• Example 7 The number average molecular weight was adjusted by adjusting the reaction time during the synthesis of a polymer consisting of a structural unit (B') whose main component is a polyester unit, the mass ratio of L-lactide used was changed, and the synthesis time The same procedure as in Example 1 was carried out except that the dilution concentration of the dilution was appropriately changed to a concentration that was easy to handle. A block copolymer consisting of the block structural unit (B) was obtained. The above-mentioned measurements and evaluations were performed on the obtained block copolymer. The results are shown in Table 1-1. The obtained block copolymer had good biodegradability, hydrolysis resistance, and elongation at break.
• Comparative example 1 At 200° C., 0.1% by mass of tin octylate was added to L-lactide and reacted until the number average molecular weight reached 100,000 to obtain polylactic acid. The obtained polylactic acid was measured and evaluated for biodegradability in activated sludge, biodegradability in compost, hydrolysis resistance, and elongation at break. The results are shown in Table 1-2.
• the block copolymer obtained in Comparative Example 1 had low values of hydrolysis resistance and elongation at break, and also had poor biodegradability. This is thought to be because it does not have a structural unit (B) whose main component is a polyester unit.
• the block copolymer obtained in Comparative Example 3 had low biodegradability, low hydrolysis resistance, and low elongation at break. This is thought to be because the diol used as a raw material does not have an alkyl group as a branched chain.
• PLLA Poly L-lactic acid
• MPD 3-methyl-1,5-pentanediol
• DEPD 2,4-diethyl-1,5-pentanediol
• MPDiol 2-methyl-1,3-propanediol
• BD 1,4- Butanediol
• PG Propylene glycol
• Adipic acid SA Succinic acid
• the present invention contains a block structural unit (A) containing a specific polylactic acid unit (a) as a main component and a block structural unit (B) containing a polyester unit (b) as a main component.
• the block copolymers of embodiments exhibit good biodegradability, hydrolysis resistance, and elongation at break. Furthermore, in this embodiment, the glass transition temperature of the block copolymer is preferably low, and low-temperature properties can be expected depending on the application. Therefore, the industrial utility of the block copolymer of this embodiment is extremely high.

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• 2023
  • 2023-06-14 EP EP23823939.6A patent/EP4541836A1/en active Pending
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