Biodegradable polyurethane resin

Abstract

The purpose of the present invention is to provide a biodegradable polyurethane resin which, as a molded body, exhibits excellent mechanical properties (strength and toughness) that can be practically used, and which is not susceptible to the generation of highly toxic aromatic amines. A biodegradable polyurethane resin according to the present disclosure is a biodegradable polyurethane resin having a structural unit derived from a polylactone polyol and a structural unit derived from an aliphatic diisocyanate having 7 or more carbon atoms and not having a side chain. A method for producing a biodegradable polyurethane resin according to the present invention comprises a step in which a component comprising at least a polylactone polyol and an aliphatic diisocyanate having 7 or more carbon atoms and not having a side chain is reacted with each other.

Description

Technical Field

[0001] The present disclosure relates to a biodegradable polyurethane resin. This application claims priority to Japanese Patent Application No. 2022-149032 filed in Japan on September 20, 2022, the contents of which are incorporated herein by reference. Background Art

[0002] In recent years, from the viewpoint of reducing the burden on the natural environment, biodegradable resin materials that can be degraded in the natural environment have attracted attention and various developments are being actively carried out. Among them, regarding polyurethane resins as reactants of polyols and polyisocyanates, biodegradable polyurethane resins tend to have poor mechanical properties (strength, toughness, etc.), and therefore developments are being carried out to improve the mechanical properties.

[0003] For example, Patent Document 1 discloses a biodegradable thermoplastic polyurethane elastomer prepared by mixing polycaprolactone copolymer polyol having alkyl side chains in the molecular chain, poly(ethylene-propylene) copolymer polyol, 4,4′-diphenylmethane diisocyanate, and 1,3-propylene glycol in a specific mixing ratio.

[0004] For example, Patent Document 2 discloses a biodegradable polyurethane urea obtained using a biodegradable polyester diol (poly-ε-caprolactone diol, etc.), a diisocyanate (lysine diisocyanate (LDI), etc.), and an aliphatic diamine having a side chain (1,2-butanediamine (1,2-BDA), etc.).

[0005] For example, Patent Document 3 discloses a biodegradable polyurethane obtained by using poly-ε-caprolactone diol, lysine diisocyanate (LDI) or butane diisocyanate (BDI), and a chain extender (1,4-butanediol (1,4-BG) or the like).

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2006-070129

[0009] Patent Document 2: Japanese Patent Application Publication No. 2009-203404

[0010] Patent Document 3: Japanese Patent Application Publication No. 2012-062370 Summary of the invention

[0011] Problems to be solved by the invention

[0012] However, the biodegradable thermoplastic polyurethane elastomer of Patent Document 1 has problems such as insufficient biodegradability and generation of highly toxic aromatic amines during degradation, which burdens the environment. In addition, the biodegradable polyurethane urea of ​​Patent Document 2 and the biodegradable polyurethane of Patent Document 3 have problems such as insufficient mechanical properties in actual use and insufficient productivity due to long curing time.

[0013] Therefore, an object of the present disclosure is to provide a biodegradable polyurethane resin, which exhibits excellent mechanical properties (strength, toughness) that can be actually used as a molded body, and is not prone to produce highly toxic aromatic amines. In addition, another object of the present disclosure is to provide a biodegradable polyurethane resin, which exhibits excellent mechanical properties (strength, toughness) that can be actually used as a molded body, has excellent productivity of the molded body (low viscosity, short curing time), and is not prone to produce highly toxic aromatic amines.

[0014] Solutions for solving problems

[0015] The inventors of the present disclosure have conducted intensive studies and have found that the above-mentioned technical problems can be solved by a biodegradable polyurethane resin having specific structural units. The present disclosure relates to the invention completed based on these findings.

[0016] That is, the present disclosure provides a biodegradable polyurethane resin having a structural unit derived from a polylactone polyol and a structural unit derived from an aliphatic diisocyanate having 7 or more carbon atoms and having no side chain.

[0017] Preferably, the polylactone polyol is a compound represented by the following formula (1).

[0018] [Chemical formula 1]

[0019]

[0020] [In formula (1), R 1 represents an m-valent hydrocarbon group, R 2 represents a divalent hydrocarbon group, m represents an integer of 2 to 10, and n represents an integer of 1 to 35]

[0021] The biodegradable polyurethane resin may further have a structural unit derived from an aliphatic diol.

[0022] It is preferred that the aliphatic diol be a diol having a linear alkylene group.

[0023] It is preferred that the biodegradable polyurethane resin has a structural unit derived from a reaction product of the polylactone polyol and the aliphatic diisocyanate and a structural unit derived from the aliphatic diol.

[0024] In the biodegradable polyurethane resin, a molar ratio of the structural unit derived from the aliphatic diol to the structural unit derived from the polylactone polyol (aliphatic diol / polylactone polyol) may be 0.10 to 3.00.

[0025] The present disclosure also provides a method for producing a biodegradable polyurethane resin, comprising a step of reacting components containing at least a polylactone polyol and an aliphatic diisocyanate having 7 or more carbon atoms and having no side chain.

[0026] Preferably, the production method includes a step of reacting a reaction product obtained by reacting the polylactone polyol and the aliphatic diisocyanate in advance with an aliphatic diol.

[0027] Preferably, in the above method, an equivalent ratio (NCO / OH) of NCO groups of the aliphatic diisocyanate to a total of OH groups of the polylactone polyol and the aliphatic diol is 0.90 to 1.10.

[0028] The present disclosure also provides a molded body, which is formed from the above-mentioned biodegradable polyurethane resin.

[0029] Effects of the Invention

[0030] By using the biodegradable polyurethane resin disclosed in the present invention, a molded product can be obtained that does not generate highly toxic aromatic amines during degradation and has excellent mechanical properties that can be used in practice. In addition, by using the biodegradable polyurethane resin disclosed in the present invention, a molded product can be obtained with excellent productivity that does not generate highly toxic aromatic amines during degradation and has excellent mechanical properties that can be used in practice. DETAILED DESCRIPTION

[0031] <Biodegradable polyurethane resin>

[0032] The biodegradable polyurethane resin disclosed herein has a structural unit derived from a polylactone polyol and a structural unit derived from an aliphatic diisocyanate having 7 or more carbon atoms and having no side chain. The biodegradable polyurethane resin preferably further includes a reaction product obtained by reacting components including at least the polylactone polyol and the diisocyanate.

[0033] (Polylactone polyol)

[0034] The polylactone polyol used in the present disclosure is preferably a reaction product of a polyol as a biodegradable polyol and a lactone.

[0035] The polylactone polyol is preferably a 2-10-functional (more preferably 2-6-functional, more preferably 2-4-functional) polylactone polyol having 2-10 (more preferably 2-6-functional, further preferably 2-4-functional) hydroxyl groups, and is particularly preferably a bifunctional polylactone diol having 2 hydroxyl groups.

[0036] The polylactone polyol is also preferably a compound represented by the following formula (1). In formula (1), R 1 represents an m-valent hydrocarbon group, R 2 represents a divalent hydrocarbon group, m represents an integer of 2 to 10, and n represents an integer of 1 to 35.

[0037] [Chemical formula 1]

[0038]

[0039] The above m is preferably 2-6, more preferably 2-4.

[0040] The above R 1 The number of carbon atoms in the m-valent hydrocarbon group is preferably 2 to 20, more preferably 2 to 10, and still more preferably 2 to 5. 1 The m-valent hydrocarbon group is preferably a group having a structural formula obtained by removing m hydroxyl groups from the structural formula of an m-valent polyol having 2 to 20 carbon atoms (preferably 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms). In other words, the polylactone polyol is preferably a polylactone polyol having a lactone polymer chain formed starting from the hydroxyl group of the m-valent polyol.

[0041] Examples of the m-valent polyol include divalent alcohols (ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, trimethylpentanediol, cyclohexanediol, etc.), trivalent alcohols (glycerol, trimethylolpropane, etc.), tetravalent alcohols (diglycerol, pentaerythritol, methyl glucoside, tetramethylolcyclohexane, etc.), pentavalent alcohols (glucose, mannose, fructose, etc.), hexavalent alcohols (dipentaerythritol, sorbitol, etc.), and examples of 7-10-valent alcohols include sugars (sucrose, lactose, etc.), derivatives thereof, polyphenols, etc. Among them, divalent to 6-valent alcohols are preferred, divalent to 4-valent alcohols are more preferred, divalent alcohols are particularly preferred, and ethylene glycol is most preferred, from the viewpoint that the mechanical properties of the biodegradable polyurethane resin are easily improved.

[0042] The above n is preferably 1-20, more preferably 3-10.

[0043] The above R 2The divalent hydrocarbon group is also preferably a linear or branched (more preferably linear) alkylene group having 2 to 20 carbon atoms (preferably 3 to 15 carbon atoms, more preferably 4 to 10 carbon atoms). Examples of the alkylene group include methylene, ethylene, trimethylene, tetramethylene, pentamethylene, etc. These may be one or more. Among them, pentamethylene is preferred because the mechanical properties of the biodegradable polyurethane resin are easily improved.

[0044] The above R 2 The divalent hydrocarbon group is preferably a group derived from lactone. That is, the polylactone polyol is preferably a group having the above R 1 The polyol is a polylactone polyol having a lactone polymerization chain with a polymerization degree n formed by using the hydroxyl group of the polyol as a starting point.

[0045] As the above-mentioned lactone, for example, α-acetone, β-propiolactone, γ-butyrolactone, γ-valerolactone, γ-nonalactone, δ-valerolactone, ε-caprolactone, cyclopentadecalactone, cyclohexacalactone, etc. can be listed. They can be only one kind or two or more. Among them, from the aspect that the mechanical properties of the above-mentioned biodegradable polyurethane resin are easy to become excellent, ε-caprolactone is preferred.

[0046] The number average molecular weight of the polylactone polyol is preferably 300 to 80,000, more preferably 500 to 4,000, and further preferably 1,000 to 3,000. If the number average molecular weight is 300 or more, the tensile strength of the obtained biodegradable polyurethane resin is easily increased, and if the number average molecular weight is 80,000 or less, the tensile elongation is easily increased. In addition, if the number average molecular weight is 1,000 or more, both the tensile strength and the tensile elongation are easily increased, and if the number average molecular weight is 3,000 or more, the crystallization of caprolactone is easily expressed, and the tensile elongation is easily reduced.

[0047] (Diisocyanate)

[0048] The diisocyanate used in the present disclosure is an aliphatic diisocyanate having 7 or more carbon atoms and having no side chain.

[0049] The biodegradable polyurethane resin disclosed herein mainly contains structural units derived from aliphatic diisocyanates as structural units derived from diisocyanates, and thus is not likely to produce highly toxic aromatic amines during degradation. In addition, since it does not have side chains, it is not likely to hinder the aggregation of structural units derived from the above diisocyanates, and thus the mechanical properties of the above biodegradable polyurethane resin are likely to become excellent.

[0050] The number of carbon atoms of the aliphatic diisocyanate is 7 or more, preferably 7 to 22, and more preferably 7 to 10. Examples of the aliphatic diisocyanate include linear aliphatic diisocyanates (1,5-pentane diisocyanate, 1,6-hexane diisocyanate, etc.), alicyclic diisocyanates without side chains (cyclohexylene diisocyanate, (cyclohexanediyldimethylene) diisocyanate, dicyclohexylmethane-4,4-diisocyanate, etc.), etc. The aliphatic diisocyanate may also be a polymer (trimer, such as an isocyanurate group-containing diisocyanate, etc.) of the aliphatic diisocyanate or the alicyclic isocyanate. Only one of them may be used, or two or more thereof may be used. Among them, linear aliphatic diisocyanates having 7 to 10 carbon atoms are preferred because the mechanical properties of the biodegradable polyurethane resin are likely to be excellent, and pentamethylene diisocyanate is more preferred because it is easily available as a biomass raw material.

[0051] The content ratio of the structural unit derived from the aliphatic diisocyanate is preferably 1.00 to 7.00 parts by mole, more preferably 1.00 to 5.00 parts by mole, and further preferably 1.00 to 3.00 parts by mole, based on 1 part by mole of the structural unit derived from the polylactone polyol.

[0052] The viscosity of the biodegradable polyurethane resin comprising structural units derived from the above-mentioned polylactone polyol and structural units derived from the above-mentioned diisocyanate, that is, the reaction product of the above-mentioned polylactone polyol and the above-mentioned diisocyanate, is preferably 1500 mPa·s or less, more preferably 1000 mPa·s or less, and further preferably 750 mPa·s or less at 75°C when the reaction product is used as a prepolymer in the following prepolymer method.

[0053] The biodegradable polyurethane resin of the present disclosure preferably has a structural unit derived from an aliphatic diol in addition to a structural unit derived from a polylactone polyol and a structural unit derived from a diisocyanate, from the viewpoint that mechanical properties tend to be excellent.

[0054] The biodegradable polyurethane resin may be a reaction product obtained by a one-step method in which the polylactone polyol, the diisocyanate, and the aliphatic diol are reacted all at once.

[0055] In addition, from the aspect that mechanical properties are easy to become more excellent, the above-mentioned biodegradable polyurethane resin preferably has a structural unit derived from the reaction product of the above-mentioned polylactone polyol and the above-mentioned diisocyanate and a structural unit derived from an aliphatic diol. That is, the above-mentioned biodegradable polyurethane resin is preferably a reaction product obtained by a prepolymer method in which the reaction product (prepolymer) of the above-mentioned polylactone polyol and the above-mentioned diisocyanate is reacted with an aliphatic diol.

[0056] (Aliphatic diol)

[0057] The aliphatic diol used in the present disclosure is preferably a linear aliphatic diol having no side chain. The aliphatic diol used in the present disclosure preferably has 2 or more carbon atoms, more preferably 2 to 10 carbon atoms, and even more preferably 3 to 6 carbon atoms.

[0058] As the above-mentioned straight-chain aliphatic diol, for example, diols having straight-chain alkylene groups (ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, etc.), polyalkylene glycols (diethylene glycol, triethylene glycol, dipropylene glycol, etc.), etc., can be listed. Only one of them can be used, or two or more can be used. Among them, 1,4-butanediol is preferred from the aspect that the mechanical properties of the above-mentioned biodegradable polyurethane resin are easily excellent.

[0059] The molecular weight of the aliphatic diol is preferably 350 or less, more preferably 300 or less, and further preferably 200 or less. When the molecular weight is 350 or less, aggregation of structural units derived from the aliphatic diol is less likely to be inhibited, and thus the mechanical properties of the biodegradable polyurethane resin are likely to be excellent.

[0060] The content ratio of the structural unit derived from the aliphatic diol may be 0 mol part, or 0.10 to 5.00 mol parts (preferably 0.50 to 4.00 mol parts, more preferably 0.90 to 3.00 mol parts) based on 1 mol part of the structural unit derived from the polylactone polyol.

[0061] The molar ratio of the structural unit derived from the aliphatic diol to the structural unit derived from the polylactone polyol (aliphatic diol / polylactone polyol) may be 0, or 0.10 to 5.00 (preferably 0.50 to 4.00, more preferably 0.90 to 3.00).

[0062] The biodegradable polyurethane resin disclosed in the present invention may contain other structural units (structural units derived from biodegradable polyols other than the above-mentioned polylactone polyols, structural units derived from polyisocyanates other than the above-mentioned aliphatic diisocyanates having 7 or more carbon atoms and not having a side chain, structural units derived from chain extenders other than the above-mentioned aliphatic diols, etc.) as long as the effects of the present invention are not impaired.

[0063] Examples of the other biodegradable polyols include polyhydroxycarboxylic acids (polyglycolic acid, polylactic acid, polyhydroxybutyric acid, polyhydroxyvaleric acid, etc.), polyester polyols (polyglycolic acid, polylactic acid, polyhydroxybutyric acid, polyhydroxyvaleric acid, etc.), polyether polyols (polyoxyethylene glycol, polyoxypropylene glycol, polyoxyethyleneoxypropylene glycol, polyoxybutylene glycol, polyoxytetramethylene glycol, etc.), etc. These may be used alone or in combination of two or more.

[0064] The content ratio of the structural units derived from the other biodegradable polyol in the total of the structural units derived from the polylactone polyol and the other biodegradable polyol is preferably 3 mol % or less, more preferably 1 mol % or less, and further preferably 0.5 mol % or less.

[0065] Examples of the other polyisocyanates include linear aliphatic diisocyanates having 4 or less carbon atoms (such as 1,3-propane diisocyanate and 1,4-butane diisocyanate), branched aliphatic diisocyanates (such as 1,3-butane diisocyanate and 2,4,4-trimethylhexane-1,6-diisocyanate), alicyclic diisocyanates having side chains (such as L-lysine ethyl diisocyanate and isophorone diisocyanate), dimer acid diisocyanates, aromatic diisocyanates (such as diphenylmethane diisocyanate, toluene diisocyanate, dimethylbiphenyl diisocyanate, xylylene diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, tetramethylxylene diisocyanate, etc.), etc. These may be used alone or in combination of two or more.

[0066] The content ratio of the structural units derived from the above-mentioned other polyisocyanates in the total of the structural units derived from the above-mentioned aliphatic diisocyanate having 7 or more carbon atoms and the above-mentioned other polyisocyanates is preferably 3 mol% or less, more preferably 1 mol% or less, and further preferably 0.5 mol% or less.

[0067] Examples of the other chain extenders include aliphatic diols having side chains (1,2-propylene glycol, 1,3-butylene glycol, 3-methyl-1,5-pentanediol, etc.), alicyclic diols (1,6-cyclohexanedimethanol, etc.), aliphatic diamines (1,2-propylene diamine, 1,3-propylene diamine, 1,4-butylene diamine, isophorone diamine, etc.), etc. These may be used alone or in combination of two or more.

[0068] The content ratio of the structural unit derived from the other chain extender in the total of the structural units derived from the aliphatic diol and the other chain extender is preferably 3 mol % or less, more preferably 1 mol % or less, and further preferably 0.5 mol % or less.

[0069] The biodegradable polyurethane resin disclosed in the present invention may also be mixed with additives (release agent, plasticizer, colorant, antioxidant, UV stabilizer, heat stabilizer, crosslinking agent, foaming agent, foam stabilizer, urethanization catalyst, filler, etc.) to prepare a biodegradable polyurethane resin composition. The above-mentioned additives may be mixed with the raw material components before the reaction, or may be mixed by melt-kneading the biodegradable polyurethane resin obtained by the reaction.

[0070] <Method for producing biodegradable polyurethane resin>

[0071] The biodegradable polyurethane resin disclosed in the present invention can be obtained by reacting components including at least a polylactone polyol and an aliphatic diisocyanate having no side chain and having 7 or more carbon atoms (the above-mentioned polylactone polyol, the above-mentioned diisocyanate, and the aliphatic diol as required). The above-mentioned polylactone polyol, the above-mentioned diisocyanate, and the above-mentioned aliphatic diol are the same as those described in the above-mentioned biodegradable polyurethane resin.

[0072] As a method for reacting the components including the above-mentioned polylactone polyol and diisocyanate, for example, there can be mentioned: a one-step method for reacting them all at once, and a prepolymer method for reacting a reaction product (prepolymer) obtained by reacting the above-mentioned polylactone polyol and the above-mentioned diisocyanate in advance with an aliphatic diol. Among them, the prepolymer method is preferred because the molecular structure of the degradable polyurethane resin is easy to become uniform and the mechanical properties of the above-mentioned biodegradable polyurethane resin are easy to become excellent.

[0073] In the reaction, the equivalent ratio (NCO / OH) of the NCO groups of the diisocyanate to the total OH groups of the polylactone polyol and the aliphatic diol is preferably 0.90 to 1.10, more preferably 0.95 to 1.05, and even more preferably 0.97 to 1.03.

[0074] In the above reaction, the molar ratio of the aliphatic diol to the polylactone polyol (aliphatic diol / polylactone polyol) may be 0, or 0.10 to 5.00 (preferably 0.50 to 4.00, more preferably 0.90 to 3.00).

[0075] The viscosity of the prepolymer in the prepolymer method is preferably 1500 mPa·s or less at 75°C, more preferably 1000 mPa·s or less, and further preferably 750 mPa·s or less. If the viscosity is 1500 mPa·s or less, the moldability of the molding material before the reaction is excellent, so the productivity of the molded body is excellent. The viscosity can be measured, for example, using a viscometer (product name "VISCOMETER TV-622", manufactured by Toki Sangyo Co., Ltd.).

[0076] When the biodegradable polyurethane resin is obtained by a one-step method, the reaction temperature is, for example, preferably 20 to 220° C., more preferably 45 to 180° C., and further preferably 70 to 140° C. The reaction time is, for example, preferably 50 to 900 minutes, more preferably 100 to 600 minutes, and further preferably 150 to 300 minutes.

[0077] In the case of obtaining the above-mentioned biodegradable polyurethane resin by a prepolymer method, the reaction temperature when obtaining the prepolymer is, for example, preferably 20 to 200°C, more preferably 45 to 150°C, and further preferably 70 to 100°C. The reaction time of the reaction to obtain the prepolymer is not particularly limited as long as it continues until the isocyanate group concentration in the reaction solution reaches the desired value, and is, for example, 10 to 400 minutes, 20 to 200 minutes, or 30 to 100 minutes. The reaction temperature when the above-mentioned prepolymer is reacted with an aliphatic diol is, for example, preferably 20 to 220°C, more preferably 45 to 180°C, and further preferably 70 to 140°C. The reaction time is, for example, preferably less than 420 minutes, more preferably 360 minutes, and further preferably less than 300 minutes. If the reaction time is less than 240 minutes, the reaction time is short, so the productivity is excellent.

[0078] The obtained biodegradable polyurethane resin may be subjected to heat treatment, for example, at 100° C. or lower for 1 to 100 hours, as necessary.

[0079] In the production of the biodegradable polyurethane resin, an urethanization catalyst (such as a tertiary amine compound and an organic metal compound) may be used.

[0080] <Molding>

[0081] The biodegradable polyurethane resin disclosed in the present invention can be made into a biodegradable molded body that exhibits excellent mechanical properties (strength, toughness) that can be actually used, for example, by the following methods: a method of shaping a liquid molding material before the reaction and then allowing it to react and solidify to form a molding; a method of softening and melting it by heating after the reaction to form a molding; or a method of using a solution obtained by dissolving the biodegradable polyurethane resin after the reaction to form a molding.

[0082] Specific examples of the molding method are not particularly limited, and examples thereof include: coating, injection molding, vacuum molding, extrusion molding, calendering molding, blow molding, inflation molding, rotational molding, slush molding, foam molding, compression molding, stamping molding, casting, dipping and other well-known and commonly used molding methods.

[0083] Specific examples of the molded article include, but are not particularly limited to, films, sheets, hoses, tubes, packing materials, vibration-proof materials, bonding materials, coating films, coating materials, fibers, foams, synthetic leathers, elastomers, etc. The molded article can be preferably used in a wide range of applications, such as clothing / non-clothing products, packaging materials, household / sundry products, furniture parts, machine parts, electrical / electronic components, parts of automobiles and other vehicles, components of industrial products, civil engineering / construction materials, agricultural products, fishery products, gardening products, sanitary products, medical / nursing products, sports / leisure products, etc.

[0084] The biodegradable polyurethane resin of the present disclosure preferably has a Shore A hardness of 80 or more, more preferably 85 or more, as measured by the evaluation method described in Examples.

[0085] The biodegradable polyurethane resin of the present disclosure has a tensile strength of preferably 5 MPa or more, more preferably 7 MPa or more, as measured by the strength evaluation method described in Examples.

[0086] The biodegradable polyurethane resin of the present disclosure has a tensile strength measured by the toughness evaluation method described in Examples, preferably 500% or more, more preferably 550% or more.

[0087] Each scheme disclosed in this specification may also be combined with any other feature disclosed in this specification. Each configuration and combination thereof in each embodiment is an example, and the addition, omission, substitution and other changes of the configuration may be appropriately made within the scope of the subject matter of this disclosure. In addition, each invention disclosed in this disclosure is not limited by the embodiment or the following examples, but only by the patent claims.

[0088] Example

[0089] Hereinafter, one embodiment of the present disclosure will be described in more detail based on examples.

[0090] The raw material components used in the examples and comparative examples of the present disclosure are as follows.

[0091] Polycaprolactone polyol A1: bifunctional polycaprolactone diol, trade name "PLACCEL 210N", number average molecular weight 1000, manufactured by DAICEL Corporation.

[0092] Polycaprolactone polyol A2: bifunctional polycaprolactone diol, trade name "PLACCEL 220N", number average molecular weight 2000, manufactured by DAICEL Corporation.

[0093] Diisocyanate B1: 1,5-pentane diisocyanate, trade name "STABiO PDI", manufactured by Mitsui Chemicals, Inc.

[0094] Diisocyanate B2: diphenylmethane diisocyanate, trade name "MILLIONATE MT", manufactured by TOSOH Corporation.

[0095] Diisocyanate B3: L-lysine ethyl diisocyanate, trade name "LDI", manufactured by Alfa Aesar.

[0096] Aliphatic diol C: 1,4-butanediol, trade name "14BG", molecular weight 90.12, manufactured by Mitsubishi Chemical Co., Ltd.

[0097] <Example 1>

[0098] Polylactone polyol A1 (1.00 mol part) and diisocyanate B1 (2.00 mol part) were charged into a glass container and reacted at 80° C. until the isocyanate group concentration (measured according to method B of JIS K1603-1:2007) in the reaction solution did not change, thereby obtaining a prepolymer.

[0099] The aliphatic diol C (1.00 mol part) was further added to the glass container so that the equivalent ratio (NCO / OH) of the NCO group of the diisocyanate B1 to the total OH group of the polylactone polyol A1 and the aliphatic diol C was 0.99, and the mixture was uniformly mixed and degassed using a rotation-revolution type stirring device (product name "Awatori Rentaro AR-250", manufactured by THINKY Co., Ltd.) to obtain a liquid material for molding.

[0100] The obtained liquid molding material was injected into a mold, and heated together with the mold in an oven at 120°C for 960 minutes to react and solidify, and then cured at 23°C and 50% RH for 48 hours to obtain a hardness measurement sample (rectangular, 13 mm in the longitudinal direction, 20 mm in the lateral direction, and 2 mm in thickness) and a tensile test sample (dumbbell-shaped (JIS K 6251, No. 3), 100 mm in the longitudinal direction, 25 mm in the lateral direction, and 2 mm in thickness).

[0101] The viscosity of the prepolymer was measured / evaluated, the curing time of urethane was measured / evaluated for the liquid molding material, and the color tone, touch, hardness, melting point / melting enthalpy, strength, toughness and biodegradability were measured / evaluated for the samples.

[0102] (Prepolymer viscosity)

[0103] The viscosity of the prepolymer at 75° C. was measured using a viscometer (product name “VISCOMETER TV-22”, manufactured by Toki Sangyo Co., Ltd.) The lower the viscosity of the prepolymer, the easier it is to inject, which means that the productivity of the molded article is excellent.

[0104] (Urethane curing time)

[0105] The storage modulus was measured using a rotational rheometer (product name "MCR302", manufactured by Anton Paar) at a strain of 5%, a frequency of 10 Hz, and a temperature of 120°C. The time when the storage modulus reaches a certain value without changing was evaluated as the urethane curing time. The shorter the urethane curing time, the better the productivity of the molded article.

[0106] (tone)

[0107] The hardness measurement sample was visually observed for appearance at 23° C. and 50% RH to evaluate whether or not it was transparent.

[0108] (Touch)

[0109] The hardness measurement sample was evaluated for elasticity by touch with fingers at 23° C. and 50% RH.

[0110] (hardness)

[0111] The hardness of the sample for measurement was measured in accordance with JIS K 6253 using a Shore A type durometer (manufactured by Shimadzu Corporation).

[0112] (Strength, toughness)

[0113] For the above-mentioned tensile test sample, a tensile test was conducted at 23°C and 50% RH using a TENSILON universal testing machine (product name "RTC-1350A", manufactured by A&D Co., Ltd.) with a distance between markings of 20 mm and a tensile speed of 500 mm / min, and the stress (tensile strength) at an elongation of 300% and the elongation (elongation at break) at sample break were measured. A greater tensile strength indicates a better strength, and a greater elongation at break indicates a better toughness.

[0114] (Biodegradability)

[0115] According to ISO 14855-1, the biodegradability after 180 days was evaluated at 58°C (±2°C) under aerobic composting conditions. A larger value indicates better biodegradability.

[0116] <Examples 2 to 5, Comparative Examples 1 to 3>

[0117] The same procedure as in Example 1 was carried out except that the raw material components and / or molar parts were changed to those described in the following Table 1. In Comparative Example 3, a molded body capable of measurement and evaluation could not be obtained.

[0118] The results of the measurements and evaluations are summarized in Table 1 below.

[0119] [Table 1]

[0120]

[0121] In the table, “-” means that no measurement or evaluation was performed.

[0122] The biodegradable polyurethane resins of Examples 1 to 5 showed excellent mechanical properties, were practically usable, and had excellent biodegradability (tensile strength 7 to 12 MPa, breaking strength 505 to 674%, biodegradability 90 days). In addition, in Example 1, the prepolymer viscosity was low (694 mPa·s) and the urethane curing time was short (225 minutes), thus showing excellent productivity.

[0123] On the other hand, among the biodegradable polyurethane resins of Comparative Examples 1 and 2 that generate highly toxic aromatic amines, the biodegradable polyurethane resin of Comparative Example 1 has poor biodegradability (biodegradability 30%) and poor productivity (prepolymer viscosity 2666 mPa·s). The biodegradable polyurethane resin of Comparative Example 3 could not be removed from the mold for testing, and had poor mechanical properties (strength, toughness).

[0124] Modifications of the invention disclosed herein will be described below.

[0125] [Supplementary Note 1] A biodegradable polyurethane resin comprising a structural unit derived from a polylactone polyol and a structural unit derived from an aliphatic diisocyanate having 7 or more carbon atoms and having no side chain.

[0126] [Supplementary Note 2] The biodegradable polyurethane resin according to Supplementary Note 1, wherein the polylactone polyol is a compound represented by the following formula (1).

[0127] [Chemical formula 1]

[0128]

[0129] [In formula (1), R 1 represents an m-valent hydrocarbon group, R 2 represents a divalent hydrocarbon group, m represents an integer of 2 to 10, and n represents an integer of 1 to 35]

[0130] [Supplementary Note 3] The biodegradable polyurethane resin according to Supplementary Note 2, wherein m is 2 to 6 (preferably 2 to 4).

[0131] [Supplement 4] The biodegradable polyurethane resin according to Supplement 2 or 3, wherein the R 1It is a hydrocarbon group obtained by removing m hydroxyl groups from the structural formula of an m-valent polyol having 2 to 20 carbon atoms (preferably 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms), and the m-valent is 2 to 6 (preferably 2 to 4, more preferably 2).

[0132] [Supplementary Note 5] The biodegradable polyurethane resin according to Supplementary Note 2 or 3, wherein the R 1 It is a divalent hydrocarbon group formed by removing a hydroxyl group from ethylene glycol.

[0133] [Supplementary Note 6] The biodegradable polyurethane resin according to any one of Supplementary Notes 2 to 5, wherein n is 1 to 20 (preferably 3 to 10).

[0134] [Supplementary Note 7] The biodegradable polyurethane resin according to any one of Supplementary Notes 2 to 6, wherein the R 2 It is a linear or branched (preferably linear) alkylene group having 2 to 20 carbon atoms (preferably 3 to 15 carbon atoms, more preferably 4 to 10 carbon atoms).

[0135] [Supplementary Note 8] The biodegradable polyurethane resin according to any one of Supplementary Notes 2 to 6, wherein the R 2 It is pentamethylene.

[0136] [Supplementary Note 9] The biodegradable polyurethane resin according to Supplementary Note 1, wherein the polylactone polyol is a reaction product of a polyol and a lactone.

[0137] [Supplementary Note 10] The biodegradable polyurethane resin according to Supplementary Note 9, wherein the polyol is a divalent to hexavalent (preferably a divalent to tetravalent, more preferably a divalent) alcohol.

[0138] [Supplement 11] The biodegradable polyurethane resin according to Supplement 9, wherein the polyol is ethylene glycol.

[0139] [Note 12] The biodegradable polyurethane resin according to any one of Notes 9 to 11, wherein the lactone is at least one selected from α-acetone, β-propiolactone, γ-butyrolactone, γ-valerolactone, γ-nonanolactone, δ-valerolactone, ε-caprolactone, cyclopentadecalactone and cyclohexadecanolactone.

[0140] [Appendix 13] The biodegradable polyurethane resin according to any one of Appendices 9 to 11, wherein the lactone is ε-caprolactone.

[0141] [Supplement 14] The biodegradable polyurethane resin according to any one of Supplements 9 to 13, wherein the number average molecular weight of the polylactone polyol is 300 to 80,000 (preferably 500 to 4,000, more preferably 1,000 to 3,000).

[0142] [Supplement 15] The biodegradable polyurethane resin according to any one of Supplements 1 to 14, wherein the aliphatic diisocyanate has 7 or more carbon atoms (preferably 7 to 22, more preferably 7 to 10).

[0143] [Appendix 16] The biodegradable polyurethane resin according to any one of Appendices 1 to 15, wherein the aliphatic diisocyanate is a linear aliphatic diisocyanate, an alicyclic diisocyanate having no side chain, or a polymer thereof.

[0144] [Supplement 17] The biodegradable polyurethane resin according to any one of Supplements 1 to 15, wherein the aliphatic diisocyanate is pentamethylene diisocyanate.

[0145] [Note 18] The biodegradable polyurethane resin according to any one of Notes 1 to 17, wherein the content ratio of the structural unit derived from the aliphatic diisocyanate is 1.00 to 7.00 mol parts (preferably 1.00 to 5.00 mol parts, more preferably 1.00 to 3.00 mol parts) relative to 1 mol part of the structural unit derived from the polylactone polyol.

[0146] [Note 19] The biodegradable polyurethane resin according to any one of Notes 1 to 18, wherein the viscosity of the reaction product of the polylactone polyol and the diisocyanate is 1500 mPa·s or less (preferably 1000 mPa·s or less, more preferably 750 mPa·s or less) at 75°C.

[0147] [Appendix 20] The biodegradable polyurethane resin according to any one of Appendices 1 to 19, further comprising a structural unit derived from an aliphatic diol.

[0148] [Supplementary Note 21] The biodegradable polyurethane resin according to Supplementary Note 20, wherein the aliphatic diol is a diol having a linear alkylene group with 2 or more carbon atoms (preferably 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms).

[0149] [Supplementary Note 22] The biodegradable polyurethane resin according to Supplementary Note 20, wherein the aliphatic diol is 1,4-butanediol.

[0150] [Appendix 23] The biodegradable polyurethane resin according to any one of Appendices 20 to 22, wherein the molecular weight of the aliphatic diol is 350 or less (preferably 300 or less, more preferably 200 or less).

[0151] [Appendix 24] The biodegradable polyurethane resin according to any one of Appendices 20 to 23, wherein the biodegradable polyurethane resin has a structural unit derived from a reaction product of the polylactone polyol and the aliphatic diisocyanate, and a structural unit derived from the aliphatic diol.

[0152] [Note 25] The biodegradable polyurethane resin according to any one of Notes 20 to 24, wherein the molar ratio of the structural units derived from the aliphatic diol to the structural units derived from the polylactone polyol (aliphatic diol / polylactone polyol) is 0.10 to 5.00 (preferably 0.50 to 4.00, more preferably 0.90 to 3.00).

[0153] [Note 26] The biodegradable polyurethane resin according to any one of Notes 1 to 25, which contains structural units derived from other biodegradable polyols other than the polylactone polyol, and the content ratio of the structural units derived from the other biodegradable polyols in the total of the structural units derived from the polylactone polyol and the other biodegradable polyols is 3 mol% or less (preferably 1 mol% or less, more preferably 0.5 mol% or less).

[0154] [Note 27] The biodegradable polyurethane resin according to any one of Notes 1 to 26, which contains structural units derived from other polyisocyanates other than the aliphatic diisocyanate having no side chain and having 7 or more carbon atoms, and the content ratio of the structural units derived from the other polyisocyanate in the total of the structural units derived from the aliphatic diisocyanate having no side chain and having 7 or more carbon atoms and the other polyisocyanate is 3 mol% or less (preferably 1 mol% or less, more preferably 0.5 mol% or less).

[0155] [Note 28] The biodegradable polyurethane resin according to any one of Notes 20 to 27, which contains structural units derived from other chain extenders other than the aliphatic diol, and the content ratio of the structural units derived from the other chain extenders in the total of the structural units derived from the aliphatic diol and the other chain extenders is 3 mol% or less (preferably 1 mol% or less, more preferably 0.5 mol% or less).

[0156] [Supplementary Note 29] A method for producing a biodegradable polyurethane resin, comprising a step of reacting components containing at least a polylactone polyol and an aliphatic diisocyanate having 7 or more carbon atoms and having no side chain.

[0157] [Supplementary Note 30] The method for producing a biodegradable polyurethane resin according to Supplementary Note 29, further comprising a step of reacting a reaction product obtained by reacting the polylactone polyol and the aliphatic diisocyanate in advance with an aliphatic diol.

[0158] [Note 31] A method for producing a biodegradable polyurethane resin according to Note 29 or 30, wherein the equivalent ratio (NCO / OH) of the NCO group of the diisocyanate to the total OH group of the polylactone polyol and the aliphatic diol is 0.90 to 1.10 (preferably 0.95 to 1.05, more preferably 0.97 to 1.03).

[0159] [Supplement 32] The method for producing a biodegradable polyurethane resin according to Supplement 30 or 31, wherein the molar ratio of the aliphatic diol to the polylactone polyol (aliphatic diol / polylactone polyol) is 0.

[0160] [Note 33] The method for producing a biodegradable polyurethane resin according to Note 30 or 31, wherein the molar ratio of the aliphatic diol to the polylactone polyol (aliphatic diol / polylactone polyol) is 0.10 to 5.00 (preferably 0.50 to 4.00, more preferably 0.90 to 3.00).

[0161] [Note 34] A method for producing a biodegradable polyurethane resin according to Note 30, 31 or 33, wherein the viscosity of the reaction product obtained by pre-reacting the polylactone polyol and the aliphatic diisocyanate is less than 1500 mPa·s (preferably less than 1000 mPa·s, more preferably less than 750 mPa·s) at 75°C.

[0162] [Supplementary Note 35] A molded body comprising the biodegradable polyurethane resin according to any one of Supplementary Notes 1 to 28.

[0163] Industrial Applicability

[0164] By using the biodegradable polyurethane resin disclosed in the present invention, a molded product can be obtained that does not generate highly toxic aromatic amines during degradation and has excellent mechanical properties that can be used in practice. In addition, by using the biodegradable polyurethane resin disclosed in the present invention, a molded product can be obtained with excellent productivity that does not generate highly toxic aromatic amines during degradation and has excellent mechanical properties that can be used in practice.

Claims

1. A biodegradable polyurethane resin comprising a structural unit derived from a polylactone polyol and a structural unit derived from an aliphatic diisocyanate having 7 or more carbon atoms and having no side chain.

2. The biodegradable polyurethane resin according to claim 1, wherein The polylactone polyol is a compound represented by the following formula (1): [Chemical formula 1] In formula (1), R 1 represents an m-valent hydrocarbon group, R 2 represents a divalent hydrocarbon group, m represents an integer of 2 to 10, and n represents an integer of 1 to 35.

3. The biodegradable polyurethane resin according to claim 2, wherein The biodegradable polyurethane resin further has a structural unit derived from an aliphatic diol.

4. The biodegradable polyurethane resin according to claim 3, wherein The aliphatic diol is a diol having a linear alkylene group.

5. The biodegradable polyurethane resin according to claim 3, wherein The biodegradable polyurethane resin has a structural unit derived from a reaction product of the polylactone polyol and the aliphatic diisocyanate and a structural unit derived from the aliphatic diol.

6. The biodegradable polyurethane resin according to any one of claims 3 to 5, wherein The molar ratio of the structural unit derived from the aliphatic diol to the structural unit derived from the polylactone polyol, that is, aliphatic diol / polylactone polyol, is 0.10 to 3.

00.

7. A method for producing a biodegradable polyurethane resin, wherein: The method comprises a step of reacting components containing at least a polylactone polyol and an aliphatic diisocyanate having 7 or more carbon atoms and having no side chain.

8. The method for producing a biodegradable polyurethane resin according to claim 7, wherein: The method comprises the step of reacting a reaction product obtained by reacting the polylactone polyol and the aliphatic diisocyanate in advance with an aliphatic diol.

9. The method for producing a biodegradable polyurethane resin according to claim 7 or 8, wherein: The equivalent ratio of NCO groups contained in the aliphatic diisocyanate to the total OH groups contained in the polylactone polyol and the aliphatic diol, that is, NCO / OH, is 0.90 to 1.

10. 10 . A molded product, comprising the biodegradable polyurethane resin according to claim 1 .

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