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
  • 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
  • C08G63/06—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from hydroxycarboxylic acids
  • C08G63/08—Lactones or lactides

Definitions

• the present invention relates to a block copolymer that has excellent biodegradability, hydrolysis resistance, and handling 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.
• Attempts to improve the drawbacks of polylactic acid include, for example, techniques for copolymerizing polyesters with various characteristics and polylactic acid, and techniques for creating compositions by adding additives such as chain extenders and fillers (for example, (See Patent Documents 1 to 4), and techniques using stereo complexes of polylactic acid are being considered (for example, see Patent Document 5). Furthermore, studies are also being conducted on applications that utilize compositions containing polylactic acid. For example, a pressure-sensitive adhesive composition using a biodegradable raw material that sufficiently satisfies adhesive properties has been disclosed (see, for example, Patent Document 6).
• Japanese Patent Application Publication No. 9-100344 Japanese Patent Application Publication No. 2004-231772 Japanese Patent Application Publication No. 2005-330318 JP2007-269842A Japanese Patent Application Publication No. 2011-153275 Japanese Patent Application Publication No. 2021-169586
• 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. .
• biodegradability As environmental awareness increases, it is required to exhibit biodegradability over a wider range of areas.
• 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. Furthermore, bioplastics are desired to be easy to handle as resin materials.
• the present invention is as follows.
• 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 diol (b1) has hydroxyl groups at both ends of the main chain.
• [4] The block copolymer according to any one of [1] to [3], wherein the aliphatic diol (b1) is 3-methyl-1,5-pentanediol.
• the block copolymer of the present 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 average molecular weight is greater than 10,000.
• the present inventors have conducted various studies on formulations for imparting a wide range of biodegradability, excellent hydrolysis resistance, and handling 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 when the number average molecular weight of the block copolymer is within a specific numerical range, the block copolymer becomes solid and has excellent handling properties, and also has excellent hydrolysis resistance.
• 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 an alkyl group as a branched chain and has 5 to 9 carbon atoms.
• the aliphatic diol is characterized in that the aliphatic dicarboxylic acid (b2) has 5 or more and 12 or less carbon atoms. 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.
• 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. Therefore, it does not necessarily mean that the effects of the present invention can be obtained if the polymer is amorphous. In addition, it is not clear why the presence of the polyester unit (b) enables both a wide range of biodegradability and excellent hydrolysis resistance, which are contradictory, to be achieved.
• 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, and poly-DL-lactic acid, and poly-L-lactic acid and poly-D-lactic acid are preferred. is more preferable.
• 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 number average molecular weight of the block structural unit (A) is preferably 1,000 to 100,000, more preferably 5,000 to 25,000, and even more preferably 8,200 to 15,000. 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 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 4 or less, the hydrolysis resistance may be poor.
• the biodegradability may be poor.
• the number of carbon atoms in the aliphatic diol (b1) is preferably 6 or more and 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 and 8 or less, more preferably 3 or more, still more preferably 4 or more, and even more preferably is 5 or more.
• 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, 2,2-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-pentanediol, 2,4-diethyl-1,5
• a combination of is an example of a preferred embodiment, and a combination of 3-methyl-1,5-pentanediol and adipic acid is an example of a more preferred embodiment.
• 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 preferably 2,500 or more, more preferably 4,000 or more, and still more preferably 5,000 or more. Further, the number average molecular weight of the block structural unit (B) is preferably less than 100,000, more preferably less than 50,000, even more preferably less than 40,000, even more preferably less than 36,000, even more preferably It is less than 25,000, may be less than 20,000, and may be less than 15,000. Within the above numerical range, the block copolymer tends to have excellent flexibility and impact resistance.
• 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 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 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 preferably less than 100,000, more preferably less than 82,000, even more preferably less than 60,000, even more preferably 58,000 or less, and even more preferably It is preferably 44,000 or less, even more preferably 35,000 or less, and may be 30,000 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 (B), the number average molecular weight of the block structural unit (A), and the number of each block structural unit.
• the melting point of the block copolymer is preferably 125°C or higher and lower than 185°C, more preferably 130°C or higher and 180°C or lower, and still more preferably 140°C or higher and 170°C or lower.
• the melting point of the block copolymer can be determined by a differential scanning calorimeter, and specifically can be measured by the method described in Examples.
• 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.
• 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.
• the pressure was reduced to 2,000 Pa and reacted for 3 hours, and then the pressure was reduced to 80 Pa and the reaction was carried out while checking the number average molecular weight until the number average molecular weight reached 9,500. ) 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 40% 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.
• Examples 2 to 5 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 synthesized. 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 handling properties, biodegradability, and hydrolysis resistance.
• Example 6 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.
• a block structural unit (A) mainly composed of polylactic acid units (a) and a polyester unit (b) were prepared in the same manner as in Example 1 except that the number average molecular weight was adjusted by adjusting the reaction time.
• a block copolymer consisting of block structural units (B) as a component was synthesized. 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 handling properties, biodegradability, and hydrolysis resistance.
• 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
• Adipic acid SA Succinic acid
• this embodiment contains a block structural unit (A) mainly composed of a specific polylactic acid unit (a) and a block structural unit (B) mainly composed of a polyester unit (b).
• This block copolymer has good biodegradability and hydrolysis resistance, and is solid, so it has excellent handling properties. Therefore, the industrial utility of the block copolymer of this embodiment is extremely high.

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• 2023
  • 2023-06-14 WO PCT/JP2023/022009 patent/WO2023243648A1/ja not_active Ceased
  • 2023-06-14 JP JP2024528896A patent/JPWO2023243648A1/ja active Pending
  • 2023-06-14 EP EP23823938.8A patent/EP4541835A1/en active Pending
  • 2023-06-14 CN CN202380046572.0A patent/CN119403858A/zh active Pending
  • 2023-06-14 US US18/874,380 patent/US20250346710A1/en active Pending

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