Multi-block copolyester ether thermoplastic elastomer chemical foams and midsoles of athletic shoes made therefrom

Abstract

A multi-block copolyester ether thermoplastic elastomer foam is prepared from an aromatic polyester compound and contains a short chain segment structure, a long chain segment structure, and a chain extender residual functional group. The short chain segment structure contains both an aromatic dicarboxylic acid ethylene glycol ester block structure and an aromatic dicarboxylic acid butylene glycol ester block structure. The long chain segment structure contains a polyether dihydric alcohol block structure, wherein the polyether dihydric alcohol block structure is 45 to 65 parts by weight based on 100 parts by weight of the multi-block copolyester ether thermoplastic elastomer foam. The multi-block copolyester ether thermoplastic elastomer foam has a melting point of not higher than 170°C and a melt flow index of less than 20 g / 10 min. The multi-block copolyester ether thermoplastic elastomer foam has the advantages of light weight, low compression set, and high resilience.

Description

Technical Field

[0001] The present invention relates to a multi-block copolyester ether thermoplastic elastic chemical foam and a sports shoe midsole made thereof. Background Art

[0002] Generally speaking, ideal athletic shoes require lightweight, low shock absorption and cushioning (g-value), low compression set, and high rebound. A lower g-value indicates better shock absorption and cushioning performance in the midsole, while a higher rebound value indicates better energy return. In other words, the higher the rebound value, the better, while the lower the g-value, the better. However, typical athletic shoe midsoles often lack both shock absorption and rebound performance. The higher the energy return and rebound value, the worse the shock absorption and cushioning performance (the higher the g-value). Therefore, highly elastic midsole materials (rebound value >50%) often fail to provide adequate shock absorption and cushioning performance (the recommended g-value for athletic shoe midsoles is 9-15). Furthermore, a midsole material must have a certain hardness to provide optimal support and wear resistance. However, excessive hardness results in poor shock absorption and cushioning. The majority of midsole materials used in sports shoes currently on the market are ethylene-vinyl acetate (EVA), EVA / polyethylene (PE), thermoplastic urethane (TPU) foam materials, etc. However, the above materials have at least the following disadvantages: (1) The density of EVA foam material is high (generally between 0.2-0.3 g / cm 3 ), high compression set (generally greater than 50%), and low rebound rate (generally the rebound rate of EVA foam materials and their mixtures is about 30%). (2) TPU foam materials have a high density, so the midsoles of sports shoes made of TPU foam materials are heavy and hard, resulting in insufficient shock absorption performance of the sports shoes.

[0003] Therefore, there is a need for a foam material for the midsole of sports shoes that can meet the requirements of lightweight, low compression set, and high rebound rate. The foam material should be compatible with the chemical foaming mixing process and equipment currently used in the shoemaking industry, such as closed mixers and chemical foaming molding processes.

[0004] In terms of material properties, thermoplastic polyether ester elastomer (TPEE), which possesses both soft and hard segments, can be foam-molded into athletic shoe midsoles. This material meets the requirements for lightweight, low compression set, and high rebound, making it a suitable material for athletic shoe midsoles. By regulating the crystallinity of the hard segments of the TPEE backbone and the flexibility and mobility of the soft segments, a balance is achieved, providing the midsole with excellent elasticity while maintaining good hardness.

[0005] US7795320B2 discloses the use of recycled PET depolymerized with diols to produce a random copolyester ether. This method differs significantly from the current technology for preparing multi-block copolyester ether thermoplastic elastomers. Regarding material properties, US7795320B2 emphasizes a tensile modulus range of 20-1200 MPa, which is significantly different from the current technology's requirement that the elastomer, after foaming, meet the performance requirements of low compression set and high rebound for use in athletic shoe midsoles.

[0006] Patent TW154470 discloses a sports shoe midsole containing a thermoplastic multi-block copolymer elastomer. This multi-block copolymer elastomer is produced by conventional polymerization of a low-molecular-weight diol and an aromatic dicarboxylic acid. This differs significantly from the present invention, which utilizes diol depolymerization to produce a multi-block copolyester ether thermoplastic elastomer.

[0007] Patent TWI637008B discloses an ester elastomer foamed molded body, in which the short chain segment of the ester elastomer is polybutylene terephthalate. Compared with the short chain segment structure of the present technology, the two have significantly different structures. The foamed body is a fused body formed by multiple foamed particles fused together, which is also completely different from the foamed body structure of the present technology.

[0008] US20200087476A1 discloses a method for manufacturing a thermoplastic elastic foam, wherein the elastomer is a polyester copolymer mixed with nylon or ethylene-vinyl alcohol copolymer, and its structure is completely different from the present technology. Summary of the Invention

[0009] The present invention provides a multi-block copolyester ether thermoplastic elastic foam that can be used as a shoe midsole component. Notably, experimental data confirms that the copolyester ether in the multi-block copolyester ether thermoplastic elastic foam of the present invention has a block structure, whereas copolyester ethers typically prepared by traditional polymerization methods have a random structure. Therefore, the copolyester ether of the present invention differs significantly from copolyester ethers prepared by conventional polymerization methods.

[0010] The multi-block copolyester ether thermoplastic elastic foam provided by the present invention is prepared from an aromatic polyester compound and comprises a short-chain segment structure, a long-chain segment structure, and a residual functional group of a chain extender. The short-chain segment structure comprises both an aromatic dicarboxylic acid ethylene glycol ester block structure and an aromatic dicarboxylic acid butylene glycol ester block structure. The long-chain segment structure comprises a polyether diol block structure, wherein the polyether diol block structure accounts for 45 to 65 parts by weight based on 100 parts by weight of the multi-block copolyester ether thermoplastic elastic foam. The multi-block copolyester ether thermoplastic elastic foam has a melting point not higher than 170°C and a melt flow index less than 20 g / 10 min.

[0011] In some embodiments, the aromatic dicarboxylic acid ethylene glycol ester block structure and the aromatic dicarboxylic acid butylene glycol ester block structure are formed by depolymerization or partial depolymerization of an aromatic polyester compound.

[0012] In some embodiments, the aromatic dicarboxylic acid ethylene glycol ester block structure and the aromatic dicarboxylic acid butylene glycol ester block structure formed by depolymerization or partial depolymerization of the aromatic polyester compound include p-phenylene, m-phenylene, or a combination thereof.

[0013] In some embodiments, the short chain segment structure further comprises a block structure formed by esterification of C2-C6 aliphatic dicarboxylic acid and C2-C4 diol.

[0014] In some embodiments, the C2-C6 aliphatic dicarboxylic acid comprises glutaric acid, adipic acid, or a combination thereof.

[0015] In some embodiments, the C2-C4 diol comprises ethylene glycol, butanediol, or a combination thereof.

[0016] In some embodiments, the polyether diol block structure is formed by reacting a depolymerized substance formed by depolymerization or partial depolymerization of an aromatic polyester compound with polytetramethylene ether glycol, wherein the weight average molecular weight of the polytetramethylene ether glycol is in the range of 650 to 4000 g / mole.

[0017] In some embodiments, the polyether diol block structure further comprises a block structure formed by esterification of C2-C6 aliphatic dicarboxylic acid and polytetramethylene ether glycol.

[0018] In some embodiments, the residual functional groups of the chain extender include epoxy groups, isocyanate groups, methylol groups, imino groups, or combinations thereof.

[0019] In some embodiments, the multi-block copolyester ether thermoplastic elastic foam further comprises a sulfonic acid group reaction residue, wherein the sulfonic acid group reaction residue is selected from the group consisting of 5-sulfonic isophthalic acid, sodium 5-sulfonic isophthalate, and combinations thereof.

[0020] In some embodiments, the aromatic polyester compound has a divalent group as shown below

[0021] The present invention also provides a multi-block copolyester ether thermoplastic elastic foam comprising the following (a) to (k).

[0022] (a) an aromatic dicarboxylic acid ethylene glycol ester block structure having the general formula (1):

[0023]

[0024] Wherein R is a divalent group formed by depolymerization or partial depolymerization of an aromatic polyester compound G is -C2H4-.

[0025] (b) an aromatic dicarboxylic acid butanediol ester block structure having the general formula (2):

[0026]

[0027] wherein R is as defined above, and G' is -C4H8-.

[0028] (c) an aliphatic dicarboxylic acid ethylene glycol ester block structure having the general formula (3):

[0029]

[0030] wherein R' is a C2-C6 divalent aliphatic functional group, and G is as defined above.

[0031] (d) aliphatic dicarboxylic acid butylene glycol ester block structure having the general formula shown in formula (4):

[0032]

[0033] wherein R' and G' are as defined above.

[0034] (e) a polyester ether block structure having the general formula (5):

[0035]

[0036] Wherein R" is a divalent group formed by depolymerization or partial depolymerization of an aromatic polyester compound or a C2-C6 divalent aliphatic functional group, G" is -C2H4-O-C4H8-.

[0037] (f) a dicarboxylic acid-polytetramethylene ether glycol block structure having the general formula (6):

[0038]

[0039] wherein R" has the same definition as above; P is the divalent group remaining after removing two hydroxyl groups from polytetramethylene ether glycol, and its weight average molecular weight ranges from 650 to 4000 g / mole.

[0040] (g) Residues from reactions with metal catalysts or mixtures of metal catalysts.

[0041] (h) Residual functional groups from the reaction of antioxidants or residues from the reaction of antioxidant mixtures.

[0042] (i) Residual functional groups of chain extenders.

[0043] (j) Residues after chemical blowing agent reaction.

[0044] (k) Fillers.

[0045] The multi-block copolyester ether thermoplastic elastic foam has a closed-cell structure and a specific gravity of 0.19 to 0.24.

[0046] In some embodiments, the metal catalyst in the metal catalyst reaction residue or the metal catalyst mixture reaction residue is a monovalent metal compound, a divalent metal compound, or a combination thereof.

[0047] In some embodiments, the multi-block copolyester ether thermoplastic elastic foam has a compression set of no more than 50%.

[0048] In some embodiments, the multi-block copolyester ether thermoplastic elastic foam has a rebound rate greater than 60%.

[0049] In some embodiments, the multi-block copolyester ether thermoplastic elastic foam has a Shore C hardness of not less than 50.

[0050] In some embodiments, the residual functional groups of the chain extender include epoxy groups, isocyanate groups, methylol groups, imino groups, or combinations thereof.

[0051] The present invention also provides a sports shoe midsole, which is made from the multi-block copolyester ether thermoplastic elastic foam.

[0052] The present invention also provides a method for preparing a multi-block copolyester ether thermoplastic elastic foam. The method comprises the following steps: (1) providing polyethylene terephthalate (PET) produced through a recycling process; (2) adding 1,4-butanediol to the PET to undergo an alcoholysis reaction, and obtaining a first intermediate product, wherein the molar ratio of 1,4-butanediol to the PET is 2:1 to 10:1; (3) adding a catalyst to cause the first intermediate product to undergo an ester exchange reaction and form a second intermediate product, wherein the ester exchange reaction is carried out at 150°C to 240°C, and the second intermediate product contains at least butylene terephthalate. (4) adding polytetramethylene ether glycol and the second intermediate product to carry out polymerization reaction to prepare a multi-block copolyester ether thermoplastic elastomer, wherein the polytetramethylene ether glycol is 45 to 65 parts by weight based on 100 parts by weight of the multi-block copolyester ether thermoplastic elastomer, and the melting point of the multi-block copolyester ether thermoplastic elastomer is not higher than 170°C, and the melt flow index is not higher than 20g / 10min; and (5) preparing a foamed body by chemical foaming process of the multi-block copolyester ether thermoplastic elastomer.

[0053] In some embodiments, the first intermediate product comprises terephthalic acid, isophthalic acid, bis(hydroxyethyl) terephthalate, bis(hydroxybutyl) terephthalate, bis(hydroxyethyl) isophthalate, bis(hydroxybutyl) isophthalate, bis(hydroxyethyl) adipate, bis(hydroxybutyl) adipate, 1,4-butanediol, ethylene glycol, diethylene glycol, or a combination thereof.

[0054] In some embodiments, the catalyst is a monovalent metal compound, a divalent metal compound, or a combination thereof.

[0055] In some embodiments, the catalyst is a titanium compound, a tin compound, an antimony compound, or a combination thereof.

[0056] In some embodiments, step (3) further comprises removing excess diol by vacuuming after forming the second intermediate product.

[0057] In some embodiments, the second intermediate product further comprises butylene isophthalate oligomers, ethylene isophthalate oligomers, butylene adipate oligomers, ethylene adipate oligomers, or a combination thereof, and co-tetramethylene terephthalate oligomers, co-tetramethylene isophthalate oligomers, co-tetramethylene adipate oligomers, or a combination thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] To make the features, advantages and embodiments of the present invention more apparent, the accompanying drawings are described as follows:

[0059] Figure 1This is the nuclear magnetic resonance analysis result of Example 1 of the present invention;

[0060] Figure 2 and Figure 3 The NMR analysis results of Comparative Example 1 and Comparative Example 2 are respectively;

[0061] Figure 4 The X-ray diffraction analysis (XRD analysis) results of Example 1;

[0062] Figure 5 is the X-ray diffraction analysis result of Comparative Example 5;

[0063] Figure 6 is the X-ray diffraction analysis result of Example 2;

[0064] Figure 7 is the X-ray diffraction analysis result of Comparative Example 6;

[0065] Among them, the symbols are as follows:

[0066] 410, 420, 430, 440, 510, 520, 530, 540, 610, 620, 630, 640, 710, 720, 730, 740: curves. DETAILED DESCRIPTION

[0067] To provide a more detailed and complete description of the present disclosure, the following provides illustrative descriptions of implementations and specific embodiments of the present disclosure; however, these are not the only ways to implement or use the specific embodiments of the present disclosure. The embodiments disclosed below may be combined or substituted with each other where beneficial, and other embodiments may be added to one embodiment without further description or explanation. In the following description, many specific details will be described in detail to enable the reader to fully understand the following embodiments. However, the embodiments of the present disclosure can be practiced without these specific details.

[0068] One aspect of the present disclosure provides a method for preparing a multi-block copolyester ether thermoplastic elastomer foam. The method is environmentally friendly in that it does not release harmful substances during the manufacturing process. The method comprises steps (1) to (5). In step (1), a polyethylene terephthalate that is recycled is provided. In some embodiments, the polyethylene terephthalate that is recycled in step (1) refers to ester particles or fibers that are recycled via mechanical recycling or via chemical recycling. In some embodiments, the polyethylene terephthalate in step (1) is recycled from a polyester product that is physically or chemically recycled from a full or partial bio-based feedstock. In some embodiments, the recycled polyester refers to ester particles or fibers that are obtained by recycling PET flakes through a series of processes such as label removal, washing, removing impurities, cutting, and increasing viscosity.

[0069] In step (2), 1,4-butanediol is added to the polyethylene terephthalate to perform alcoholysis to produce a first intermediate product, wherein the molar ratio of 1,4-butanediol to polyethylene terephthalate is 2:1 to 10:1. In some embodiments, the molar ratio of 1,4-butanediol to polyethylene terephthalate is, for example, 2.2:1, 2.3:1, or 2.4:1. In some embodiments, 1,4-butanediol and adipic acid are added to the polyethylene terephthalate to perform alcoholysis and transesterification to produce a first intermediate product, wherein the molar ratio of 1,4-butanediol to polyethylene terephthalate is 2:1 to 10:1, and the molar ratio of adipic acid to polyethylene terephthalate is 1:30 to 1:2. In some embodiments, the first intermediate product comprises terephthalic acid, isophthalic acid, bis-hydroxyethyl terephthalate, bis-hydroxybutyl terephthalate, bis-hydroxyethyl isophthalate, bis-hydroxybutyl isophthalate, bis-hydroxyethyl adipate, bis-hydroxybutyl adipate, 1,4-butanediol, ethylene glycol, diethylene glycol, or a combination thereof.

[0070] In step (3), a catalyst is added to perform transesterification of the first intermediate product to form a second intermediate product. In some embodiments, the transesterification is performed at a temperature of 150°C to 240°C, for example, 160°C, 170°C, 180°C, 190°C, 200°C, 215°C, or 220°C, to avoid high reaction temperature that causes 1,4-butanediol to crack to form tetrahydrofuran. In some embodiments, the second intermediate product comprises at least bis-butanediol terephthalate oligomers and bis-ethylene glycol terephthalate oligomers. In one embodiment, the transesterification is performed at a pressure of 3 kg / cm 2 When the temperature reaches 190°C, the catalyst is added and maintained for 60 minutes, and then the temperature is increased to 230°C, and the pressure is maintained at 3 kg / cm2 The reaction was stirred at 230°C (108 rpm) for 4 hours, with the 1,4-butanediol fully refluxed into the reaction tank. The pressure was then released to atmospheric pressure, with stirring maintained at 230°C for 3 hours. This ensured that the intermediate component was primarily bis(hydroxybutyl terephthalate) (PBT), while simultaneously releasing 1,4-butanediol, ethylene glycol, water, tetrahydrofuran, and mixtures thereof, under atmospheric pressure.

[0071] In some embodiments, the catalyst is a monovalent metal compound, a divalent metal compound, or a combination thereof. In some embodiments, the catalyst is a titanium compound, a tin compound, an antimony compound, or a combination thereof. In one embodiment, the catalyst is tetrabutyltitanium. In some embodiments, an antioxidant and an anti-UV absorber may be added to prevent thermal cracking during the reaction.

[0072] The second intermediate product comprises an ethoxy segment and a butoxy segment. In some embodiments, the second intermediate product further comprises a butylene isophthalate oligomer, an ethylene isophthalate oligomer, a butylene adipate oligomer, an ethylene adipate oligomer, or a combination thereof, and a terephthalate co-tetramethylene glycol ether oligomer, an isophthalate co-tetramethylene glycol ether oligomer, an adipate co-tetramethylene glycol ether oligomer, or a combination thereof. In some embodiments, step (3) further comprises removing excess diol by vacuum extraction after forming the second intermediate product. In one embodiment, after the degree of transesterification reaches 95%, excess butanediol is removed by vacuum extraction.

[0073] In step (4), polytetramethylene ether glycol is added to the second intermediate product for polymerization reaction to obtain a multi-block copolyester ether thermoplastic elastomer. In one embodiment, polytetramethylene ether glycol is added to the second intermediate product, the main component of which is butylene terephthalate, at 230° C. and normal pressure for polymerization reaction. In some embodiments, the weight molecular weight of polytetramethylene ether glycol ranges from 650 to 2000. In some embodiments, the amount of polytetramethylene ether glycol added is 55%, 60%, 65%, or 70%, respectively, based on the weight of the polyester pellets.

[0074] Then, it moves to the superposition tank for structural recombination reaction. At this time, the superposition stage temperature is set at 250°C and the reaction is carried out under high vacuum less than 1 Torr.

[0075] In some embodiments, step (4) comprises adding a catalyst to promote the polymerization reaction, wherein the catalyst comprises an antimony compound, a germanium compound, a magnesium compound, a manganese compound, a phosphorus compound, a nitrogen compound, an organic peroxide, or a combination thereof. In one embodiment, the catalyst is antimony trioxide.

[0076] Based on 100 parts by weight of the multi-block copolyester ether thermoplastic elastomer, the polytetramethylene glycol is present in an amount of 45 to 65 parts by weight. The prepared multi-block copolyester ether thermoplastic elastomer has a melting point of no higher than 170° C., a melt flow index of no higher than 20 g / 10 min, and a relative viscosity of 2.3 to 3.55.

[0077] In step (5), the copolyester ether is prepared into a multi-block copolyester ether thermoplastic elastic foam. In some embodiments, step (5) comprises using a chemical foaming process to prepare the copolyester ether thermoplastic elastic foam, which includes adding the copolyester ether into a closed mixer, and then sequentially adding an activator, a filler, a lubricant, a chain extender, and a foaming agent, and mixing them uniformly to form a mixture. Next, the mixture is added into an air-cut granulator and extruded and pelletized to form mixture particles. The mixture particles are then placed into a foaming mold for compression foaming to obtain the copolyester ether thermoplastic elastic foam.

[0078] In some embodiments, based on 100 parts of the copolyester ether thermoplastic elastomer base material, auxiliary agents are added in proportion, for example: 0.5-5 parts of an activator, 5-20 parts of a filler, 0-5 parts of a lubricant, 1-20 parts of a chain extender, and 0.5-10 parts of a foaming agent. In some embodiments, the activator includes a metal oxide, zinc oxide, and magnesium oxide. In some embodiments, the filler includes talc and calcium carbonate. In some embodiments, the lubricant includes stearic acid and an unsaturated fatty acid. In some embodiments, the chain extender includes a polymer modified with an epoxy resin group, having a molecular weight of 3000-7000, wherein the epoxy resin group equivalent weight is 200-500 g / mol. In some embodiments, the foaming agent includes azodicarbonamide, azodimethylthiamine, 4,4-oxybisbenzenesulfonylhydrazine, dinitrosopentamethyltetramine, sodium bicarbonate, or a combination thereof.

[0079] It is noteworthy that the copolyester ether thermoplastic elastic foam prepared by the method of the present invention comprises a copolyester ether, wherein the copolyester ether comprises a hard segment structure and a soft segment structure. The hard segment structure comprises a short-chain segment diol, and the soft segment structure comprises a long-chain segment diol. In some embodiments, the hard segment structure simultaneously has an aromatic dicarboxylic acid ethylene glycol ester block structure and an aromatic dicarboxylic acid butylene glycol ester block structure (for example, an ethoxy group comprising ethylene glycol (EG) and a butoxy group comprising butanediol (BG)). In some embodiments, the long-chain segment diol of the soft segment structure is, for example, polytetramethylene ether glycol.

[0080] Due to the hard segment structure containing different carbon number structures (i.e. diethylene glycol and dibutylene glycol), this will cause the crystalline region of the hard segment structure to phase separate, thereby changing the hardness, compression set, resilience and shock absorption value of the copolyester ether, so that the copolyester ether thermoplastic elastomer foam formed by foaming the copolyester ether has the advantages of light weight, low compression set and high resilience.

[0081] Another aspect of the present application provides a multi-block copolyester ether thermoplastic elastomer foam prepared from an aromatic polyester compound. The multi-block copolyester ether thermoplastic elastomer foam comprises a short segment structure, a long segment structure and a chain extender residual functional group. The short segment structure has both aromatic dicarboxylic acid ethylene glycol ester block structure and aromatic dicarboxylic acid butylene glycol ester block structure. The long segment structure has polyether diol block structure, wherein the polyether diol block structure is 45 to 65 parts by weight based on 100 parts by weight of the multi-block copolyester ether thermoplastic elastomer foam. The multi-block copolyester ether thermoplastic elastomer foam has a melting point of not higher than 170°C and a melt flow index of less than 20 g / 10 min.

[0082] In some embodiments, the aromatic dicarboxylic acid ethylene glycol ester block structure and the aromatic dicarboxylic acid butylene glycol ester block structure are formed by depolymerization or partial depolymerization of the aromatic polyester compound.

[0083] In some embodiments, the aromatic dicarboxylic acid ethylene glycol ester block structure and the aromatic dicarboxylic acid butylene glycol ester block structure formed by depolymerization or partial depolymerization of the aromatic polyester compound comprise p-phenylene, m-phenylene or a combination thereof.

[0084] In some embodiments, the short segment structure further comprises a block structure formed by esterification of C2-C6 aliphatic dicarboxylic acid and C2-C4 diol. In some embodiments, the C2-C6 aliphatic dicarboxylic acid comprises glutaric acid, adipic acid or a combination thereof. In some embodiments, the C2-C4 diol comprises ethylene glycol, butanediol or a combination thereof.

[0085] In some embodiments, the polyether diol block structure is formed by reaction of depolymerized material formed by depolymerization or partial depolymerization of the aromatic polyester compound with polytetramethylene ether glycol, wherein the polytetramethylene ether glycol has a weight average molecular weight in the range of 650-4000 g / mole.

[0086] In some embodiments, the polyether diol block structure further comprises a block structure formed by esterification of C2-C6 aliphatic dicarboxylic acid and polytetramethylene ether glycol.

[0087] In some embodiments, the chain extender residual functional group comprises epoxy, isocyanate, hydroxymethyl, imino or a combination thereof.

[0088] In some embodiments, the multi-block copolyester ether thermoplastic elastic foam further comprises a sulfonic acid group reaction residue, wherein the sulfonic acid group reaction residue is selected from the group consisting of 5-sulfonic isophthalic acid, sodium 5-sulfonic isophthalate, and combinations thereof.

[0089] In some embodiments, the aromatic polyester compound has a divalent group as shown below

[0090] Another aspect of the present invention provides a multi-block copolyester ether thermoplastic elastic foam comprising the following (a) to (k).

[0091] (a) an aromatic dicarboxylic acid ethylene glycol ester block structure having the general formula (1):

[0092]

[0093] Wherein R is a divalent group formed by depolymerization or partial depolymerization of an aromatic polyester compound G is -C2H4-.

[0094] (b) an aromatic dicarboxylic acid butanediol ester block structure having the general formula (2):

[0095]

[0096] wherein R is as defined above, and G' is the divalent group -C4H8- remaining after removing the two hydroxyl groups.

[0097] (c) an aliphatic dicarboxylic acid ethylene glycol ester block structure having the general formula (3):

[0098]

[0099] wherein R' is a C2-C6 divalent aliphatic functional group, for example, a functional group of a dicarboxylic acid excluding a dihydroxyl group, for example, R' is a functional group of glutaric acid or adipic acid excluding a dihydroxyl group, and G is as defined above.

[0100] (d) aliphatic dicarboxylic acid butylene glycol ester block structure having the general formula shown in formula (4):

[0101]

[0102] wherein R' and G' are as defined above.

[0103] (e) a polyester ether block structure having the general formula (5):

[0104]

[0105] wherein R" is a divalent radical formed by depolymerization or partial depolymerization of an aromatic polyester compound or a C2-C6divalent aliphatic functional group, R" is, for example, the functional group of a dicarboxylic acid from which the dihydroxy groups have been removed, for example, R" is, for example, the functional group of glutaric acid or adipic acid from which the dihydroxy groups have been removed, and G" is -C2H4-O-C4H8-.

[0106] (f) dicarboxylic acid-polytetramethylene ether glycol block structures having the general formula shown in formula (6):

[0107]

[0108] wherein R" is as defined above; and P is the divalent radical remaining after removal of two hydroxyl groups from a polytetramethylene ether glycol having a weight average molecular weight in the range of 650 to 4000 g / mole.

[0109] (g) a metal catalyst reaction residue or a metal catalyst mixture reaction residue thereof.

[0110] (h) an antioxidant reaction residue functional group or an antioxidant mixture reaction residue thereof.

[0111] (i) a chain extender residue functional group.

[0112] (j) a chemical blowing agent reaction residue.

[0113] (k) a filler.

[0114] The multi-block copolyester ether thermoplastic elastomeric foam has a closed cell structure and a specific gravity in the range of 0.19 to 0.24.

[0115] In some embodiments, the metal catalyst in the metal catalyst reaction residue or the metal catalyst mixture reaction residue thereof is a monovalent metal compound, a divalent metal compound, or a combination thereof.

[0116] In some embodiments, the multi-block copolyester ether thermoplastic elastomeric foam has a compression set of no more than 50%. In some embodiments, the multi-block copolyester ether thermoplastic elastomeric foam has a resilience of more than 60%. In some embodiments, the multi-block copolyester ether thermoplastic elastomeric foam has a Shore C hardness of no less than 50.

[0117] In some embodiments, the chain extender residual functional group comprises an epoxy group, an isocyanate group, a hydroxymethyl group, an imino group, or a combination thereof. In some embodiments, the chain extender residual functional group is derived from a reaction of a high molecular weight polymer modified with an epoxy resin group, the high molecular weight polymer having a molecular weight of 3000-7000, wherein the epoxy resin group has an equivalent weight of 200-500 g / mol.

[0118] In some embodiments, the chemical blowing agent reaction residue is derived from a reaction of a blowing agent. In some embodiments, the blowing agent comprises azodicarbonamide, azodiisulfamides, 4,4-oxybis(benzenesulfonyl)hydrazide, diazeniumdiolate, sodium bicarbonate, or a combination thereof.

[0119] Yet another aspect of the present disclosure provides a midsole for an athletic shoe, which is made of the multi-block copolyester ether thermoplastic elastomer foam described above. In some embodiments, the multi-block copolyester ether thermoplastic elastomer foam has a specific gravity of 0.19-0.24. The midsole for an athletic shoe made of the multi-block copolyester ether thermoplastic elastomer foam described above has the advantages of light weight, low compression set, and high rebound.

[0120] The following examples are included to provide a detailed description of certain aspects of the application and to demonstrate the application to one of ordinary skill in the art. The following examples should not be construed as limiting the application.

[0121] Example 1

[0122] Take 200 g of multi-block copolyester ether thermoplastic elastomer made of polyethylene terephthalate regenerated from recycled bottle flakes by alcoholysis polymerization, 1.5 g of activator zinc oxide, and 20 g of filler talc powder, and put them into a closed mixer for the first mixing stage. The copolyester ether in Example 1 contains short-chain diols and long-chain diols. The short-chain diols contain ethylene glycol (EG) and butylene glycol (BG), and the molar ratio of ethylene glycol to butylene glycol is about 1:5, and the long-chain diol is polytetramethylene ether glycol, and the addition amount of polytetramethylene ether glycol is 65%. Add 1 g of stearic acid, 12 g of chain extender (epoxy copolymer, commercially available model ADR4370), and 4 g of chemical blowing agent for mixing, and the mixing temperature is 130°C.

[0123] Then, the mixed material is placed into a foaming mold for compression molding and foaming, and the foaming temperature is 160°C, to obtain a closed-cell foam.

[0124] The resulting foams were tested and recorded for hardness, specific gravity, compression set, resilience, and shock absorption. The results are shown in Table 2. The hardness was tested according to ASTM D2240, unit Shore C. The specific gravity was tested according to ASTM D297. The compression set was tested according to ASTM D395, with a compression ratio of 50% and a test condition of 50°C for 6 hours. If the compression set of the foam is high, it means that the foam cannot return to its original size, i.e., the resilience is poor. The resilience was tested according to ASTM D2632. The shock absorption was tested according to SATRA TM142.

[0125] In addition, the structure of the copolyester ether of Example 1 was verified by nuclear magnetic resonance analysis, and the results are shown in Table 1. It was found that the copolyester ether of Example 1 indeed contained both ethoxy and butoxy segment structures. Figure 1

[0126] Examples 2 to 5

[0127] Examples 2 to 5 were prepared in a manner similar to Example 1. The weight average molecular weight (Mw) of the polytetramethylene ether glycol used in Examples 2 to 5 was 1000, 2000, 4000, and 650, respectively. In addition, a small amount of adipic acid was further included in Example 2.

[0128] Comparative Example 1

[0129] The procedure of Comparative Example 1 was similar to that of Example 1, except that the amount of polytetramethylene ether glycol added was changed to 70% in Comparative Example 1. The results of the nuclear magnetic resonance analysis of the copolyester ether of Comparative Example 1 are shown in Table 1. Figure 2

[0130] Comparative Example 2

[0131] ​​In the copolyester ether prepared in Comparative Example 2, the short-chain diol is ethylene glycol and butanediol, and the addition amount of polytetramethylene ether glycol is 70%. The polyester source used in Comparative Example 2 is a raw material prepared by esterification and polymerization of diacids and short-chain diols and polytetramethylene ether glycol. In a 50 kg reaction device, 21.6 kg of terephthalic acid (TPA), 8 kg of ethylene glycol, 11.7 kg of 1,4-butanediol, and 19.5 kg of polytetramethylene ether glycol (with a COOH / OH molar ratio of 1.5) were mixed to perform esterification. The catalyst used in the esterification reaction is tetraisopropanetitanate (TIP), and the catalyst addition amount is 16 g. The initial temperature of the esterification reaction is set to 150°C, and a staged temperature rise is used. When the temperature reaches about 220°C, which takes about 6 hours, and the byproduct distillate reaches about 6.7 kg, the reaction is transferred to the polymerization tank to perform polymerization (esterification conversion rate is about 95%). Then the polymerization reaction is performed, with a polymerization temperature of 250°C, and the vacuum is controlled below 1 torr. When the viscosity of the polymer reaches the required set value, it is sampled and analyzed, and tests such as relative viscosity (RV) are performed. Subsequent nuclear magnetic resonance analysis tests are performed. The nuclear magnetic resonance analysis results of the copolyester ether of Comparative Example 2 are shown in Table 1. Figure 3

[0132] Next, 200 g of the copolyester ether described in the previous step, 3 g of the activator zinc oxide, and 20 g of the filler talc powder were put into a closed mixer to perform mixing, and then the obtained mixture was foamed. The mixing step and the foaming step of Comparative Example 2 are similar to those of Example 1, except that the amount of chain extender ADR4370 in the mixing step is reduced to 6 g.

[0133] Comparative Example 3

[0134] The steps of Comparative Example 3 are substantially the same as those of Comparative Example 2, except that the formula of the copolyester ether is changed in Comparative Example 3, in which the short-chain diol in the copolyester ether is changed to ethylene glycol, and the addition amount of polytetramethylene ether glycol is 65%.

[0135] Comparative Example 4

[0136] Comparative Example 4 is a commercially available midsole foaming material for sports shoes, which is a finished product of TPU physically foamed.

[0137] Table 1 lists the diol (Diol) and diacid (Diacid) addition amounts, relative viscosity, melting point, and melt flow index (MI) of Examples 1-5 and Comparative Examples 1-3. The melt flow index is tested at a test temperature of 200°C with a load of 2.16 kg.

[0138] Table 1​

[0139]

[0140] Table 2 lists the physical property test results of foaming experimental examples 1A-1D and comparative examples 1, 2 and 4. The physical property test results include the hardness (Shore C) of the foam, the specific gravity (g / cm 3 ), average pore size (μm), compression set rate (%), rebound rate (%), shock absorption and cushioning (g value), etc.

[0141] Table 2

[0142]

[0143] As shown in Tables 1 and 2, the copolyester ether thermoplastic elastic foam of the present invention can meet the requirements of lightweight, low compression set, and high rebound for athletic shoes. Specifically, for Examples 1A to 1D, the rebound is greater than 60% while maintaining good shock absorption and cushioning (g-values ​​of approximately 14-15). However, the rebound of Comparative Examples 2 and 4 is less than 60%, and the shock absorption and cushioning is relatively low (g-values ​​of approximately 10-14). This demonstrates that the copolyester ether thermoplastic elastic foam of the present invention is highly suitable for athletic shoes. Furthermore, the hardness of Examples 1A to 1D is similar to that of commercially available midsole foam materials (hardness (Shore C) of approximately 47-55), yet they provide even better shock absorption and cushioning.

[0144] Table 3 lists the nuclear magnetic resonance (NMR) test results of Example 1, Comparative Example 5, Example 2, and Comparative Example 6.

[0145] Table 3

[0146]

[0147] Comparative Example 5 is a special comparative example. A copolyester was obtained using a conventional copolymerization method. The theoretical proportions of TPA, IPA, EG, BG, and PTMEG components were added and copolymerized according to Example 1. This copolyester was used as a control for NMR and XRD analysis experiments. The purpose was to compare the effects of different production methods on the molecular structure of the copolyester ether and to identify the degree of difference between the mosaic and random structures.

[0148] Depend on Figure 1As shown in Table 3, the hard segments of the copolyesterethers prepared by the method of the present invention contain both ethoxy (EG) and butoxy (BG) chain structures. Using the same diol composition ratio, the alcoholysis process of the present invention significantly increases the ethoxy (EG) content compared to conventional copolymerization methods. The presence of a large number of ethoxy and butoxy groups in the hard segments of the polyesterether can cause phase separation in the microcrystalline region. It should also be noted that conventional copolyesterethers with a mosaic structure typically have a melting point above 200°C. To achieve a melting point below 200°C, the proportion of soft segments must be increased, resulting in a more random structure. However, the copolyesterether thermoplastic elastomers of the present invention have a poly-mosaic structure with a melting point of no more than 170°C. This mosaic structure facilitates crystal alignment, resulting in a higher degree of crystallinity. This demonstrates that their structure is distinct from conventional copolyesterether structures, enabling the copolyesterether thermoplastic elastomer foams of the present invention to exhibit a rebound coefficient exceeding 60%.

[0149] Figure 4 This is the X-ray diffraction analysis (XRD analysis) result of Example 1. Figure 5 This is the XRD analysis result of Comparative Example 5. Figure 4 As shown, curve 410 is the measurement curve; curve 420 is the fitting curve; curve 430 is the fitting curve of the amorphous form; and curve 440 is the fitting curve of the crystalline form. Figure 5 As shown, curve 510 is the measured curve; curve 520 is the fitted curve; curve 530 is the fitted curve for the amorphous form; and curve 540 is the fitted curve for the crystalline form. Table 4 lists the XRD areas for Example 1 and Comparative Example 5. X-ray diffraction analysis generates a pattern by diffracting X-rays against crystals. The pattern is then compared with a database of patterns to infer the material's crystalline structure.

[0150] Table 4

[0151]

[0152] In the XRD pattern of Example 1, a hump signal representing the amorphous region and a peak signal representing the crystalline region (indicated by the arrow) can be observed between 15° and 30°. In contrast, in the pattern of Comparative Example 5, only the hump signal representing the amorphous region is observed. This indicates that Example 1 has a higher degree of crystallinity than Comparative Example 5.

[0153] Although the segment composition is the same, the different manufacturing processes result in different segment distributions. Example 1 exhibits a large segment distribution (tending to be block-like), while Comparative Example 5 exhibits a random distribution of small segments. In comparison, the segments in Example 1 are more ordered, promoting crystal alignment and resulting in higher crystallinity.

[0154] Figure 6 This is the XRD analysis result of Example 2. Figure 7 This is the XRD analysis result of Comparative Example 6. Figure 6 As shown, curve 610 is the measurement curve; curve 620 is the fitting curve; curve 630 is the fitting curve of the amorphous form; and curve 640 is the fitting curve of the crystalline form. Figure 7 As shown, curve 710 is the measured curve; curve 720 is the fitted curve; curve 730 is the fitted curve for the amorphous form; and curve 740 is the fitted curve for the crystalline form. Table 5 lists the XRD areas of Example 2 and Comparative Example 6. X-ray diffraction analysis generates a spectrum through the diffraction of X-rays and crystals, and compares it with the spectrum database to infer the arrangement structure of the material crystals. Example 2 and Comparative Example 6 have the same monomer composition. In the presence of an aliphatic diacid structure, the overall crystallinity of Example 2 (8.2%) is still higher than that of Comparative Example 6 (5.3%), indicating that the segment distribution of the present invention (alcoholysis process product) is a large segment composition (biased towards block).

[0155] Table 5

[0156]

[0157] Furthermore, the production method of the present invention does not release harmful substances during the manufacturing process, making it environmentally friendly. Furthermore, the production method of the present invention utilizes recycled bottle flakes, ester pellets or fibers made from either fully or partially biomass-based feedstocks as the source of polyethylene terephthalate.

[0158] Although the present disclosure has been described above with reference to specific embodiments, other embodiments are possible. Therefore, the spirit and scope of the claims are not limited to the description of the specific embodiments herein. Those skilled in the art will appreciate that various modifications and variations are possible without departing from the spirit and scope of the present disclosure. Therefore, the scope of protection of the present disclosure shall be determined by the appended claims.

Claims

1. A multi-block copolyester ether thermoplastic elastic chemical foam, characterized in that: The preparation method of a multi-block copolyester ether thermoplastic elastic chemical foam comprises the following steps: subjecting polyethylene terephthalate produced through a recycling process to an alcoholysis reaction with 1,4-butanediol, adding a catalyst to carry out an ester exchange reaction, and adding polytetramethylene ether glycol to carry out polymerization to produce a multi-block copolyester ether thermoplastic elastomer; and subjecting the multi-block copolyester ether thermoplastic elastomer to a chemical foaming process to produce the multi-block copolyester ether thermoplastic elastic chemical foam. The multi-block copolyester ether thermoplastic elastic chemical foam comprises: A short chain segment structure, wherein the short chain segment structure has both an ethylene terephthalate block structure and a butylene terephthalate block structure; A long chain segment structure having a polyether diol block structure; Residual functional groups of chain extenders; as well as Residues after chemical foaming agent reaction; The polyether diol block structure is formed by reacting a depolymerized substance formed by depolymerization or partial depolymerization of polyethylene terephthalate with polytetramethylene ether glycol, wherein the weight average molecular weight of the polytetramethylene ether glycol is in the range of 650 to 4000 g / mole. The polyether diol block structure accounts for 45 to 65 parts by weight of the multi-block copolyester ether thermoplastic elastic chemical foam based on 100 parts by weight. The multi-block copolyester ether thermoplastic elastic chemical foam has a melting point of no higher than 170°C, a melt flow index of less than 20 g / 10 min when tested at a temperature of 200°C and a load of 2.16 kg, a compression set of no more than 50%, and a rebound rate of greater than 60%.

2. The multi-block copolyester ether thermoplastic elastic chemical foam according to claim 1, wherein the short chain segment structure further comprises a block structure formed by an esterification reaction between a C2-C6 aliphatic dicarboxylic acid and a C2-C4 diol. 3 . The multi-block copolyester ether thermoplastic elastic chemical foam according to claim 2 , wherein the C2-C6 aliphatic dicarboxylic acid comprises glutaric acid, adipic acid or a combination thereof. 4 . The multi-block copolyester ether thermoplastic elastic chemical foam according to claim 2 , wherein the C2-C4 diol comprises ethylene glycol, butanediol or a combination thereof. 5 . The multi-block copolyester ether thermoplastic elastic chemical foam according to claim 1 , wherein the polyether diol block structure further comprises a block structure formed by esterification reaction of C2-C6 aliphatic dicarboxylic acid and polytetramethylene ether glycol. 6 . The multi-block copolyester ether thermoplastic elastic chemical foam according to claim 1 , wherein the residual functional group of the chain extender comprises an epoxy group, an isocyanate group, a hydroxymethyl group, an imino group, or a combination thereof.

7. The multi-block copolyester ether thermoplastic elastic chemical foam according to claim 1, further comprising a sulfonic acid group reaction residue, wherein the sulfonic acid group reaction residue is selected from the group consisting of 5-sulfonic isophthalic acid, sodium 5-sulfonic isophthalate, and a combination thereof.

8. A multi-block copolyester ether thermoplastic elastic chemical foam, characterized in that: The preparation method of a multi-block copolyester ether thermoplastic elastic chemical foam comprises the following steps: subjecting polyethylene terephthalate produced through a recycling process to an alcoholysis reaction with 1,4-butanediol, adding a catalyst to carry out an ester exchange reaction, and adding polytetramethylene ether glycol to carry out polymerization to produce a multi-block copolyester ether thermoplastic elastomer; and subjecting the multi-block copolyester ether thermoplastic elastomer to a chemical foaming process to produce the multi-block copolyester ether thermoplastic elastic chemical foam. The multi-block copolyester ether thermoplastic elastic chemical foam comprises: (a) an ethylene terephthalate block structure having the general formula (1): Wherein R is a divalent group formed by depolymerization or partial depolymerization of polyethylene terephthalate G is -C2H4-; (b) a butylene terephthalate block structure having the general formula (2): wherein R is as defined above, and G' is -C4H8-; (c) an aliphatic dicarboxylic acid ethylene glycol ester block structure having the general formula (3): Wherein R' is a C2-C6 divalent aliphatic functional group, and G is as defined above; (d) aliphatic dicarboxylic acid butylene glycol ester block structure having the general formula shown in formula (4): Wherein R' and G' are as defined above; (e) a polyester ether block structure having the general formula shown in formula (5): wherein R" is a divalent group formed by depolymerization or partial depolymerization of the polyethylene terephthalate or a C2-C6 divalent aliphatic functional group, G" is -C2H4-O-C4H8-; (f) a dicarboxylic acid-polytetramethylene ether glycol block structure having the general formula (6): Wherein R" is as defined above; P is the divalent group remaining after removing two hydroxyl groups from polytetramethylene ether glycol, and its weight average molecular weight ranges from 650 to 4000 g / mole; (g) metal catalyst reaction residues or metal catalyst mixture reaction residues; (h) residual functional groups from the reaction of antioxidants or residues from the reaction of antioxidant mixtures; (i) residual functional groups of chain extenders; (j) chemical blowing agent residues after reaction; and (k) fillers, The multi-block copolyester ether thermoplastic elastic chemical foam has a closed-cell structure and has a specific gravity of 0.19 to 0.24, a compression set rate of no more than 50%, and a rebound rate greater than 60%. Based on 100 parts by weight of the multi-block copolyester ether thermoplastic elastic chemical foam, the dicarboxylic acid-polytetramethylene ether glycol block structure accounts for 45 to 65 parts by weight. 9 . The multi-block copolyester ether thermoplastic elastic chemical foam according to claim 8 , wherein a metal catalyst in the metal catalyst reaction residue or the metal catalyst mixture reaction residue is a monovalent metal compound, a divalent metal compound, or a combination thereof. 10 . The multi-block copolyester ether thermoplastic elastic chemical foam according to claim 8 , wherein the multi-block copolyester ether thermoplastic elastic chemical foam has a Shore C hardness of not less than 50. 11 . The multi-block copolyester ether thermoplastic elastic chemical foam according to claim 8 , wherein the residual functional group of the chain extender comprises an epoxy group, an isocyanate group, a hydroxymethyl group, an imino group, or a combination thereof.

12. A sports shoe midsole, characterized in that: The sports shoe midsole is made from the multi-block copolyester ether thermoplastic elastic chemical foam described in claim 8.

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