TW202210273A - Molded article of expanded thermoplastic polyurethane and method for manufacturing the same - Google Patents

Abstract

The present invention provides a method for manufacturing a molded article of expanded thermoplastic polyurethane (ETPU), comprising mixing ETPU beads with a polyurethane dispersion (PUD) to obtain a mixture, and placing the mixture in a mold and performing a thermal compression process to obtain an ETPU molded article. The method of the present invention is able to utilize a compression molding equipment to obtain a thicker ETPU molded article, and the obtained ETPU molded article has improve mechanical strengths.

Description

Expanded thermoplastic polyurethane molded article and method for producing the same

The disclosure of the present invention relates to a method for manufacturing an expanded thermoplastic polyurethane molded product using a thermocompression molding apparatus. The present invention also relates to expanded thermoplastic polyurethane moldings having better mechanical strength.

Expanded thermoplastic polyurethane (or expanded thermoplastic polyurethane beads, ETPU) has low density, high elasticity and low deformation, can withstand long-term and repeated compression, can maintain its performance at low temperature, and has good resistance. Abrasion, scratch resistance and soft touch. In addition, ETPU has good stability to many solvents and UV light. Therefore, ETPU is widely used in sporting goods such as shoe materials, midsoles and insoles.

In order to improve the mechanical properties of ETPU, it is currently known to use hybrid materials comprising thermoplastic polyurethane (TPU) to prepare ETPU. CN102421846B discloses a hybrid foam comprising TPU, a polymeric hollow body such as polystyrene or styrene-acrylonitrile (SAN) filled with a blowing agent. CN103210010A discloses a method for producing a shoe sole comprising a hybrid material made of PU foam and TPU foam particles as base materials. CN101583656B discloses a hybrid material comprising a PU base material and TPU expandable particles contained in the base material.

The ETPU molding method mainly uses external heat to make the surface between the ETPU beads micro-melt to achieve the purpose of bonding and molding. Traditional molding methods mainly utilize steam chests. Of course, most of the related industries such as the footwear industry do not have steam forming equipment but only thermoforming equipment. Although it is possible to manufacture ETPU molded products using thermoforming equipment, the inability to transfer heat to the center of the ETPU molded product results in a loose structure of the ETPU molded product, and even thicker ETPU molded products cannot be molded. Therefore, the thickness of the ETPU molded product produced by the thermoforming equipment is quite limited.

CN105073363 A discloses a method of molding foamed products with hot-pressing molding equipment. After adding ETPU beads and water to a compression mold, the mold is closed and heated, and the ETPU beads are bonded by in-situ steam to make Get a molded product. However, the steam will cause undesired shrinkage of the ETPU beads, which increases the density of the molded product, and in addition, the bonding strength of the finished product is also poor. CN104098786B discloses a preparation method of ETPU foamed microspheres, which comprises mixing ETPU microspheres containing a foaming agent with water-based PU, foaming and molding in hot pressing equipment, but, the molded body obtained by this method The hardness will still increase undesired.

In order to solve the above technical problems, the industry currently needs a kind of ETPU molding products that can be manufactured by using the existing hot pressing molding equipment, and the ETPU molding products can maintain good mechanical properties, such as low density, good tensile strength and desired hardness, etc. .

An object of the present invention is to provide a method for producing an expanded thermoplastic polyurethane molded article, comprising the steps of: mixing expanded thermoplastic polyurethane (ETPU) beads with a polyurethane dispersion (PUD) to obtain a mixture; and The mixture is placed in a mold and hot-pressed to obtain an ETPU molded product.

The method of the invention can effectively improve the problem that the hot-pressing molding equipment cannot transfer heat to the center, so that the industry can use the existing hot-pressing molding equipment to produce thicker ETPU molded products. In addition, the present invention also provides an ETPU mixture which is favorable for hot pressing processing. The ETPU molded article according to the present invention can maintain good mechanical properties, such as low density, low hardness, good elastic tensile strength, and desired stretch ratio. The hot pressing forming method according to the present invention requires a shorter processing time, and can be processed at a lower temperature compared with the steam forming method, so as to save heating energy.

Another object of the present invention is to provide an expanded thermoplastic polyurethane midsole molded product, which includes a top surface, a bottom surface and a side surface, the side surface connects the top surface and the side surface and surrounds a foamed structure, wherein the structure includes mutual The first part and the second part are welded, wherein the first part is a foamed structure formed by a plurality of ETPUs. The molded product has good mechanical strength, preferably a tensile strength of about 6 kg/cm ² or more.

The present invention will be described with reference to the following examples. In addition to the following examples, the present invention may be carried out in other ways without departing from the spirit of the present invention; the scope of the present invention should not be interpreted and limited solely based on the disclosure of the specification. Other specific examples of the present invention can be derived from the claimed scope and examples. Furthermore, the features of the method of the present invention described above and below can be used not only in the combination specified, but also in other combinations, without departing from the scope of the present invention. For example, a combination of the better or better technical features or a combination of other technical contents can be covered. To facilitate understanding of the disclosure set forth herein, certain terms are defined below.

In the method of the present invention, the term "ETPU" refers to an expanded (or foamed) thermoplastic polyurethane. The term "ETPU molded product" refers to a product obtained by molding ETPU beads in a casting mold.

Suitable methods for TPU and for making ETPU substrates are known to those skilled in the art. Preferably, the ETPU substrate is manufactured according to eg WO 94/20568 A1, WO 2007/082838 A1, WO 2005/023920 A1, WO 2007/045586 A1, WO 2010/136398 A1, WO 2014/126799 A1 and WO 2013/ Any of the methods described in 153153 A1, which are incorporated herein by reference, with respect to ETPU and/or ETPU substrate products.

Thermoplastic Polyurethane (TPU) According to some embodiments of the present invention, TPU can be prepared by reacting a mixture of isocyanate (a) with a compound (b) reactive towards isocyanate, and its molar mass is preferably 0.5kg/mol to 10kg/ mol. According to some preferred embodiments of the present invention, the mixture may be further reacted with a chain extender (c) to obtain TPU with a molar mass of 0.06 kg/mol to 0.5 kg/mol. In other preferred embodiments, at least one chain regulator (c1) and at least one catalyst (d) can be used, and if appropriate at least one filler, auxiliary and/or at least one additive (e) are also added mixture to make TPU.

As previously mentioned, the usual components (a), (b), (c), (c1), (d) and (e) for the manufacture of TPUs include the following groups of substances: isocyanates (a), reactive towards isocyanates Compound (b), chain extender (c), chain regulator (c1), catalyst (d), and/or at least one conventional filler, auxiliary and/or additive (e), which are exemplified below but not used for Limit the invention.

In general, TPUs are prepared from mixtures of isocyanates (a) and isocyanate-reactive compounds (b), to which further components (c), (c1), (d) and (e) are optionally added. or by using their possible equivalent counterparts. For each of these components, a suitable single substance or a mixture thereof may be used. The components isocyanate (a), the isocyanate-reactive compound (b), and optionally the chain extender (c) and the chain regulator (c1) are generally referred to as structural components. In some preferred embodiments, isocyanate (a) may include aliphatic, cycloaliphatic, araliphatic, and/or aromatic isocyanates, and preferably diisocyanates. Preferred examples of diisocyanates include tri-, tetra-, penta-, hexa-, hepta-, and/or octamethylene diisocyanate, 2-methylpentamethylene 1,5-diisocyanate, 2-ethyl butylene 1,4-diisocyanate, pentamethylene 1,5-diisocyanate, butylene 1,4-diisocyanate, 1-isocyanato-3,3,5-trimethyl-5- Isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), 1,4- and/or 1,3-bis(isocyanatomethyl)cyclohexane (HXDI), cyclohexane 1 ,4-diisocyanate, 1-methylcyclohexane 2,4- and/or 2,6-diisocyanate, and/or dicyclohexylmethane 4,4'-, 2,4'-, and 2,2 '-diisocyanate, diphenylmethane 2,2'-, 2,4'-, and/or 4,4'-diisocyanate (MDI), naphthylene 1,5-diisocyanate (NDI), methylbenzene Phenyl 2,4- and/or 2,6-diisocyanate (TDI), diphenylmethane diisocyanate, 3,3'-dimethyldiphenyl diisocyanate, 1,2-diphenylethanedi Isocyanates, and phenylene diisocyanates.

According to some embodiments of the present invention, the isocyanate-reactive compound (b) used comprises polyester polyols, polyether polyols, and/or polycarbonate diols.

According to some embodiments of the present invention, the TPU can be prepared from at least one polyether alcohol, preferably at least one polyether diol, that is, the ETPU prepared therefrom preferably includes at least one polyether. According to some preferred embodiments of the present invention, the polyether glycols are preferably polyethylene glycol and polypropylene glycol. The molar mass of the polyether alcohol is preferably 0.6 kg/mol to 4.5 kg/mol, more preferably 0.8 kg/mol to 2.5 kg/mol. The polyether alcohols can be used as individual substances or as mixtures thereof.

According to other aspects of the present invention, polyester alcohols can be used to make TPUs. In preferred embodiments, polyester diols can be used. According to one embodiment of the present invention, the polyester diol is prepared from adipic acid and 1,4-butanediol. According to some preferred embodiments of the present invention, the molar mass of the polyester alcohol is 0.6 kg/mol to 4.0 kg/mol, preferably 0.8 kg/mol to 2.5 kg/mol.

According to some embodiments of the present invention, the average functionality of the polyol is 1.8 to 2.3, or preferably 1.9 to 2.2, especially 2.

According to some embodiments of the present invention, the chain extender (c) may comprise aliphatic, araliphatic, aromatic, and/or cycloaliphatic compounds, and may have a molar of 0.06 kg/mol to 0.5 kg/mol quality. According to some preferred embodiments of the present invention, the chain extender (c) is a compound having two functional groups, such as a diamine and/or an alkanediol having 2 to 10 carbon atoms in the alkylene radical (especially is 1,2-ethanediol, 1,4-butanediol, 1,6-hexanediol, and/or di-, tri-, tetra-, penta- with 4 to 20 carbon atoms , hexa-, hepta-, octa-, nona-, and/or dodecanediol), and the corresponding oligo- and/or polypropylene glycols. According to some preferred embodiments of the present invention, mixtures of the aforementioned chain extenders can be used to manufacture TPU.

According to some embodiments of the present invention, the chain regulator (c1) may have a molar mass of 0.03 kg/mol to 0.5 kg/mol. Chain regulators are compounds having only one isocyanate-related functional group. Chain regulators include, but are not limited to, monohydric alcohols, monofunctional amines (preferably 1-butylamine, 1-hexylamine), and/or monopolyhydric alcohols (preferably 1-butanol, 1-hexanol, and 1-octanol) ). Chain regulators can be used in mixtures of individual components to adjust the desired flow properties.

According to some embodiments of the present invention, based on the amount of the isocyanate-reactive compound (b), the amount of the chain regulator is 0 to 5% by weight, preferably 0.1 to 1% by weight.

According to some embodiments of the present invention, at least one catalyst (d) can be used to manufacture TPU, which can accelerate the NCO group of diisocyanate (a) and the compound reactive toward isocyanate, the hydroxyl group of structural component (b), ( c), and the reaction between (c1). According to some preferred embodiments of the present invention, the catalyst can be selected from tertiary amines, such as triethylamine, dimethylcyclohexylamine, N-methylmorpholine, N,N'-dimethylpiperazine, The group of 2-(dimethylaminoethoxy)ethanol, diazbicyclo[2.2.2]octane, and similar substances. In other preferred embodiments, the at least one catalyst can be selected from the group of organometallic compounds, including but not limited to titanates, iron compounds (such as iron(III) acetylacetonate), tin compounds (such as Tin (II) diacetate, tin (II) dioctoate, tin (II) dilaurate), or dialkyltin salts of aliphatic carboxylic acids (such as dibutyltin diacetate, dibutyltin dilaurate) and the like.

According to some embodiments of the present invention, the catalysts may be used individually, or a mixture of at least two of the foregoing catalysts may be used. According to some preferred embodiments of the present invention, the amount of the catalyst or catalyst mixture is 0.0001% to 0.1% by weight calculated on the amount of the isocyanate-reactive compound (b) (preferably a polyhydroxy compound). Hydrolysis stabilizers (eg polymeric and low molecular weight carbodiimides) can also be added to structural components (a) to (c) and, if appropriate (c1), together with catalyst (d) or without the use of a catalyst .

According to other aspects of the present invention, the TPU may include a phosphorus compound. In some preferred embodiments of the present invention, the phosphorus compounds include, but are not limited to, organophosphorus compounds of trivalent phosphorus, such as phosphites and phosphites. Examples of suitable phosphites are triphenyl phosphite, diphenyl alkyl phosphite, phenyl dialkyl phosphite, tris(nonylphenyl) phosphite, trilauryl phosphite, tris-octadecyl phosphite Alkyl ester, distearyl neopentaerythritol diphosphite, gins (2,4-di-tert-butylphenyl) phosphite, diisodecyl neopentaerythritol diphosphite, bis(2 ,4-di-tert-butylphenyl) neotaerythritol diphosphite, tristearyl sorbitol tri-phosphite, tetra(2,4-di-tert-butylphenyl) 4,4'-diphosphite Phenylene diphosphite, triisodecyl phosphite, diisodecyl phenyl phosphite, and diphenyl isodecyl phosphite, or mixtures thereof.

According to some embodiments of the present invention, the phosphorus compound preferably includes a phosphorus compound that is difficult to hydrolyze, because the hydrolysis of the phosphorus compound to the corresponding acid may result in damage to TPU, especially polyester TPU. Therefore, for polyester TPUs, suitable phosphorus compounds are those that are particularly resistant to hydrolysis. Preferred specific examples of anti-hydrolysis phosphorus compounds include, but are not limited to, dipropylene glycol phenyl phosphite, triisodecyl phosphite, triphenyl monodecyl phosphite, tri-isononyl phosphite, ginseng ( 2,4-di-tert-butylphenyl) phosphite, tetra(2,4-di-tert-butylphenyl) 4,4'-diphenylene diphosphite, and bis(2, 4-di-tert-butylphenyl) neopentaerythritol diphosphite, or a mixture thereof.

According to some embodiments of the present invention, the TPU may further include additives known in the art as antioxidants, light stabilizers, UV stabilizers, optical brighteners, and mold release agents.

According to some embodiments of the present invention, the molar ratios of structural components (b) and (c) can vary relatively widely. In a preferred embodiment, the molar ratio of component (b) to the total amount of chain extender (c) used varies from 10:1 to 1:10, preferably from 5:1 to 1:8, better From 3:1 to 1:4, as the content of chain extender (c) increases, the hardness of TPU can be increased.

Expanded Thermoplastic Polyurethane (ETPU) According to some preferred embodiments of the present invention, ETPU beads can be produced by a continuous process, which includes: passing TPU particles, conventional nucleating agents, additional additives, etc. through a loss-in-weight metering machine It is sent to a twin-screw extruder for heating and melting; conventional blowing agents such as liquid butane or supercritical carbon dioxide (ScCO ₂ ) are injected from the middle section of the twin-screw extruder through a metering pump to form a uniform polymer and physical blowing agent. Mixed melt; reduce the melt temperature of the rear section through temperature control; foam and granulate in the water cutting system from the screw to the discharge port to form foamed TPU beads, namely ETPU beads.

According to other preferred embodiments of the present invention, the ETPU beads can be produced by a batch process, which includes: feeding TPU particles, conventional nucleating agents, additional additives, etc. into a twin-screw extruder through a weight loss metering machine It is heated and melted in the machine and mixed into the water cutting system at the discharge port for granulation to obtain foamable TPU particles. Put the foamable TPU particles into the autoclave, add water and dispersant and stir to prevent the TPU particles from sticking; feed supercritical fluid such as ScCO ₂ ; control the immersion time until the TPU particles are allowed to stick. After being saturated with supercritical fluid, they are quickly decompressed, so that the TPU particles rapidly expand into foamed TPU beads; after drying, aging and other steps, they are prepared into foamed TPU foam beads, namely ETPU beads.

According to some embodiments of the present invention, the foaming nucleating agent suitable for the present invention is not particularly limited, such as but not limited to: inorganic fine particle solids, such as talc, silica, mica, clay, zeolite, calcium carbonate , polyethylene wax, or a combination thereof, the preferred nucleating agent is talc, such as talc available from Luzenac Pharma. Based on the total weight of the mixture, a suitable amount of foaming nucleating agent added, such as but not limited to: 0.1 to 10 wt %, preferably 0.1 to 3 wt %, more preferably 0.1 to 1.5 wt %. The suitable average particle size of foamed nucleation is, for example but not limited to: 0.01 to 100 μm, preferably 1 to 60 μm. Methods of adding foam nucleating agents are well known to those skilled in the art.

Conventional blowing agents include chemical blowing agents, such as water and/or formic acid; and physical blowing agents, which may be selected from, for example, propane, n-butane, isobutane, cyclobutane, n-pentane, isopentane, Cyclopentane, cyclohexane, dimethyl ether, methyl ethyl ether, methyl butyl ether, methyl formate, acetone and fluorinated alkanes that decompose in the troposphere and therefore do not destroy the ozone layer, such as trifluoromethane , difluoromethane, 1,1,1,3,3-pentafluorobutane, 1,1,1,3,3-pentafluoropropane, 1,1,1,2-tetrafluoroethane, difluoroethane alkane and heptafluoropropane. The blowing agent is generally used in an amount of about 0.1 to about 15 wt %, preferably about 0.1 to about 10 wt %, especially about 0.1 to about 5 wt %, based on the total weight of the reaction mass.

In the present invention, a foaming stabilizer may be selected as an additive, which is a material that promotes the formation of a regular cell structure during foaming. Examples are: silicon-containing foam stabilizers, such as siloxane-alkylene oxide copolymers and other organopolysiloxanes. The following alkoxylation products can also be used: fatty alcohols, oxygenated alcohols, fatty amines, alkylphenols, dialkylphenols, alkyl cresols, alkyl resorcinols, naphthols, alkyl naphthols, Naphthylamine, aniline, alkylaniline, toluidine, bisphenol A, alkylated bisphenol A, polyvinyl alcohol, and alkoxylation products of the following condensation products: formaldehyde and alkylphenol, formaldehyde and dioxane base phenols, formaldehyde and alkyl cresols, formaldehyde and alkyl resorcinols, formaldehyde and aniline, formaldehyde and toluidine, formaldehyde and naphthols, formaldehyde and alkyl naphthols, and formaldehyde and bisphenol A or both or A mixture of two or more of these foam stabilizers. The foam stabilizer is preferably used in an amount of about 0.5 to about 4.0% by weight, more preferably about 1.0 to about 3.0% by weight, based on the total weight of the reaction mass.

According to some preferred embodiments of the present invention, the ETPU beads have a thermoplastic polyurethane having a Shore A hardness in the range of 85 to 95, or 87 to 93, or 89 to 91, or 85 to 91, or 85 to 87.

According to some preferred embodiments of the present invention, the ETPU beads are polyether type, polyester type thermoplastic polyurethane, polycarbonate type thermoplastic polyurethane, polycaprolactone type thermoplastic polyurethane, or non-yellowing thermoplastic polyurethane.

According to some preferred embodiments of the present invention, the ETPU beads have a specific gravity of about 50 g/L to about 250 g/L, a specific gravity of about 80 g/L to about 160 g/L, preferably about 100 g/L to about 140 g/L The proportion of L.

According to some preferred embodiments of the present invention, the ETPU beads have a diameter of about 0.5 mm to about 1.5 cm, about 0.5 mm to about 15 mm, about 1 mm to about 12 mm, or about 2 mm to about 10 mm.

According to an embodiment of the present invention, the ETPU beads can be made of ETPU beads of type 6315BM, 6310BM, 6315AM, 6315BS, or 6315CM manufactured by Dadong Resin.

Polyurethane Dispersions (PUDs) Suitable polyurethane dispersions (PUDs) and methods for their preparation, such as prepolymer mixing methods, acetone methods or melt dispersion methods, are known to those skilled in the art. Reference is made to the disclosures of DE-A 1570 602, DE-A 1570 615 and DE-A 1694 062 for the manufacture of PUDs by the acetone process. For the manufacture of PUD by prepolymerization, reference may be made to the disclosure of TW 201348279 A.

The acetone method is exemplified in the following process. First, polyether or polyester polyol is reacted with isocyanate to synthesize a high-viscosity prepolymer with NCO functional groups at the end, and then add water-compatible, low-boiling solvent (acetone, butyl cyanide, etc.). ketone or tetrahydrofuran, etc.) to dilute and reduce viscosity, and then add hydrophilic monomer to react for chain extension. After completion, add water for high-speed shear emulsification. With the addition of water, a phase transition occurs, and the water becomes the continuous phase to form a water-based polyurethane system, and finally the solvent is separated by distillation.

According to one embodiment of the present invention, the acetone method is used to prepare PUD, which includes the following steps: 1. Weigh 250 g of dewatered PCD (3-methyl-1,5-pentanediol, 3MPD & 1,6-hexanediol) diol, HDO/ Mw: 2000), 4.25g end-capping agent (EO/PO Mw: 1000) and 4g catalyst Y-62 (1/80 in hexane) in a 0.5 L reaction flask, external temperature 70°C under stirring. 2. When the internal temperature reaches 65 ^o C or more, add dropwise 12g of isocyanate monomer 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane ( IPDI) and 23 g of dicyclohexylmethane diisocyanate (HDI), and heated to 90 ^° C under mixing and stirring to carry out a prepolymerization reaction for 3 hours. 3. Add the first stage acetone (~300g) to disperse and reduce the temperature to 45 ^o C. 4. After the prepolymer is dispersed, add 1 g of chain extender isophorone diamine (IPDA) and 15.8 g of sulfamate chain extender (VESTAMIN A95, EVONIK Evonik Industries) dropwise, and react for 1 hour . 5. Increase the stirring speed and add the second stage acetone (~300g) for dispersion. 6. After the dispersion is uniform, pour it into a 1L reaction flask and drop in water for phase inversion. 7. After the phase inversion is complete, perform the acetone extraction procedure. After the acetone was removed, the mixture was stirred for 1 hour and then filtered to obtain the final PUD product.

Suitable solvents in the acetone process can be general aliphatic keto-functional solvents, such as acetone or butanone, which can be added not only at the beginning of the preparation, but also partially later, if appropriate. According to some preferred embodiments of the present invention, the solvent is preferably acetone and butanone. Other solvents such as xylene, toluene, cyclohexane, butyl acetate, methoxypropyl acetate, N-methylpyrrolidine solvents with ether units or ester units can also be utilized, which can be distilled off in whole or in part , or can be completely left in the dispersion.

The prepolymer mixing method is exemplified in the following process. First, polyether or polyester polyol is reacted with isocyanate and hydrophilic monomer to synthesize a high-viscosity prepolymer with NCO functional groups at the end, and then an appropriate alkali is added. The prepolymer is neutralized, then dispersed in water, and a chain extender containing amine groups is added to react with the remaining NCO groups of the prepolymer to prepare a polyurethane dispersion (PUD).

、

；離子體化合物，例如

；擴鏈帶親水基化合物，例如

。According to some preferred embodiments of the present invention, the hydrophilic monomers include but are not limited to unilaterally capped hydrophilic compounds, such as

,

; ionic compounds such as

; chain extension compounds with hydrophilic groups, e.g.

.

According to some preferred embodiments of the present invention, the PUD can be selected from ester or ether PUD. According to an embodiment of the present invention, the PUD can be an ester PUD of type EP501A or an ether-type PUD of type EP360A manufactured by Dadong Resin.

The solids content in the PUD may be from 5% to 90% by weight, or from 30% to 85% by weight, or from 40% to 80% by weight, or from 50% to 70% by weight, based on the total weight of the PUD. According to some preferred embodiments of the present invention, the solid content of the PU dispersion is 5% to 70% by weight, more preferably 5% to 50% by weight, particularly preferably 15% to 40% by weight.

The PUD may include antioxidants and/or light stabilizers and/or other adjuvants and additives such as emulsifiers, defoamers, thickeners. Finally, fillers, plasticizers, pigments, carbon black and silica sols, aluminum dispersions, clay dispersions and asbestos dispersions, flow control agents or thixotropic agents, depending on the desired PUD properties and application .

Preparation of ETPU Molded Product In the method of the present invention, ETPU beads are mixed with PUD, and the mixture is placed in a mold for thermocompression molding to obtain an ETPU molded product. In the method of the present invention, the mixture can be heated and formed by using general oil pressure heating equipment to obtain the ETPU formed product, wherein the hot pressing equipment can be matched with a water cooling cooling system. According to an embodiment of the present invention, the heat-pressing equipment may be a heat-pressing equipment generally used for EVA.

According to an embodiment of the present invention, the method includes the steps of: preheating the mold to a specific temperature (about 80 ^o C to about 150 ^o C, preferably about 100 ^o C to about 130 ^o C), The mixture is poured into the mold, the mold is closed and heated for a period of time (about 0.5 to 20 minutes), and cooled until the temperature reaches below a certain temperature to obtain an ETPU molded product.

According to another embodiment of the present invention, the method includes the steps of: first pouring the mixture into the mold, closing the mold and heating to a specific temperature (about 90 ^° C to about 140 ^° C, preferably About 105 ^o C to about 135 ^o C) for a period of time (about 0.5 to 20 minutes), cooling until the temperature reaches a certain temperature below, so as to obtain the ETPU molded product.

According to some preferred embodiments of the present invention, the amount of the PUD in the mixture is from about 1 phr (parts by weight of PUD per 100 parts by weight of ETPU) to about 35 phr, or from about 3 phr to about 15 phr, or about 3 phr to about 10 phr, or about 5 phr to about 13 phr, or about 7 phr to about 11 phr, or about 9 phr to about 10 phr.

According to the method of the present invention, by adjusting the amount of PUD in the mixture, the obtained ETPU molded article can have desired mechanical properties, such as suitable tensile strength. According to some preferred embodiments of the present invention, the ETPU molded product has more than about 6 kg/cm ² , or more than about 7 kg/cm ² , or more than about 8 kg/cm ² , or more than about 9 kg/cm ² , or about 10 kg/ ^cm2 or more, or about 11 kg/ ^cm2 or more, or about 12 kg/ ^cm2 or more, or about 13 kg/ ^cm2 or more, or about 14 kg/ ^cm2 or more, or about 16 kg /cm ² or more tensile strength. According to other preferred embodiments of the present invention, the ETPU molded product has a hardness of about 25 to 50, or about 27 to 47, or about 29 to 43, or about 30 to 40, or about 33 to 36 Asker C. within the range.

According to some preferred embodiments of the present invention, the mold can be selected from square or spherical molds, shoe midsole molds, slipper molds, sports equipment such as dumbbell molds, bicycle airless tire molds, or bicycle seat cushion molds.

According to some preferred embodiments of the present invention, the ETPU molded product has a length of about 1 cm, or about 1.5 cm, or about 2 cm, or about 3 cm, or about 4 cm, or about 5 cm, or about 6 cm , or a thickness of about 7 cm or more. According to an embodiment of the present invention, the ETPU molded product can be a spherical molded product with a diameter of up to 7 cm. According to a preferred embodiment of the present invention, the ETPU molded article may have a thickness of up to about 10 cm.

As previously mentioned, the method of the present invention can be carried out at a temperature ranging from about 80 ^° C to about 140 ^° C by means of the thermoforming step. According to some preferred embodiments of the present invention, the heating temperature may be about 80 ^° C, or about 90 ^° C, or about 100 ^° C, or about 105 ^° C, or about 110 ^° C, or about 120 ^° C , or about 130 ^o C. In contrast, the manufacturing method using steam forming equipment must carry out the heating process at a high temperature range, usually 105 ^o C to 135 ^o C. Therefore, the method of the present invention saves heating energy compared with the traditional steam forming method.

Expanded thermoplastic polyurethane molded product The present invention further provides an expanded thermoplastic polyurethane molded product, which includes a foamed structure, wherein the structure includes a first part and a second part welded to each other, wherein the first part is made of a plurality of expanded thermoplastic polyurethane moldings. The foamed structure formed by foamed thermoplastic polyurethane (ETPU), the second part is formed by polyurethane dispersion (PUD). According to some embodiments of the present invention, the expanded thermoplastic polyurethane molding is produced by the aforementioned method.

According to some embodiments of the present invention, the molded article may be in the form of a square shape, a ball shape, a shoe midsole, a slipper mold, a sporting item, a bicycle airless tire, or a bicycle seat cushion.

According to some preferred embodiments of the present invention, as shown in FIG. 1 , the molded product is in the form of a midsole, which includes a top surface 102 , a bottom surface 104 and a side surface 106 , and the side surface 106 is connected to the top surface 102 and the bottom surface 104 and surrounds a foam structure, wherein the structure includes a first part and a second part welded to each other, wherein the first part is a foam structure formed by a plurality of ETPU, and the second part is formed by PUD .

According to some preferred embodiments of the present invention, the molded product has more than about 6 kg/cm ² , or more than about 7 kg/cm ² , or more than about 8 kg/cm ² , or more than about 9 kg/cm ² , or about 10 kg/ ^cm2 or more, or about 11 kg/ ^cm2 or more, or about 12 kg/ ^cm2 or more, or about 13 kg/ ^cm2 or more, or about 14 kg/ ^cm2 or more, or about 16 kg/ Tensile strength and mechanical strength above cm ² . According to other preferred embodiments of the present invention, the ETPU molded product has a hardness in the range of about 25 to 50, or about 27 to 47, or about 29 to 43, or about 30 to 40, or about 33 to 36 Asker C Inside.

Example Example 1 Mix 100g of thermoplastic polyurethane foam beads 6315BM (product specific gravity about 130g/L) with 10g of polyester polyurethane dispersion EP501A, preheat the mold to 135 ^o C, pour the mixed material into 1.5 In a square mold with a thickness of centimeters, hot-press at 135 ^o C for 6 minutes after the mold is closed, and after cooling and opening the mold, a block sample of 16*16*1.5cm can be obtained, and the sample density is 0.263g/cm ³ .

Example 2 Mix 70g of thermoplastic polyurethane foam beads 6315BM (product specific gravity about 130g/L) with 2.1g of polyester polyurethane dispersion EP501A, preheat the mold to 135 ^o C, pour the mixed material into 1 In a square mold with a thickness of centimeters, hot-press at 135 ^o C for 2.2 minutes after the mold is closed, and after cooling and opening the mold, a block sample of 16*16*1cm can be obtained, and the sample density is 0.273g/cm ³ .

Example 3 Mix 70 g of thermoplastic polyurethane foam beads 6315BM (product specific gravity about 130 g/L) with 3.5 g of polyester polyurethane dispersion EP501A, preheat the mold to 135 ^o C, pour the mixed material into 1 In a square mold with a thickness of centimeters, hot-press at 135 ^o C for 2.2 minutes after the mold is closed, and after cooling and opening the mold, a block sample of 16*16*1cm can be obtained, and the sample density is 0.275g/cm ³ .

Example 4 Mix 70 g of thermoplastic polyurethane foamed beads 6315BM (product specific gravity about 130 g/L) with 4.9 g of polyester polyurethane dispersion EP501A, preheat the mold to 135 ^o C, and pour the mixed material into 1 In a square mold with a thickness of centimeters, hot-press at 135 ^o C for 2.2 minutes after the mold is closed, and after cooling and opening the mold, a block sample of 16*16*1cm can be obtained, and the sample density is 0.277g/cm ³ .

Example 5 Mix 70 g of thermoplastic polyurethane foamed beads 6315BM (product specific gravity about 130 g/L) with 7 g of polyester polyurethane dispersion EP501A, preheat the mold to 135 ^o C, and pour the mixed material into 1 cm In a thick square mold, hot-press at 135 ^o C for 2.2 minutes after mold closing, and after cooling and mold opening, a block sample of 16*16*1cm can be obtained, and the sample density is 0.281g/cm ³ .

Example 6 Mix 70 g of thermoplastic polyurethane foamed beads 6315BM (product specific gravity about 130 g/L) with 7 g of polyester polyurethane dispersion EP501A, preheat the mold to 105 ^o C, and pour the mixed material into 1 cm In a thick square mold, hot-press at 105 ^o C for 6 minutes after the mold is closed, and after cooling and opening the mold, a block sample of 16* ¹⁶ *1cm can be obtained. .

Example 7 Mix 70 g of thermoplastic polyurethane foamed beads 6315BM (product specific gravity about 130 g/L) with 7 g of polyester polyurethane dispersion EP501A, preheat the mold to 80 ^o C, and pour the mixed material into 1 cm In a thick square mold, hot-press at 80 ^o C for 15 minutes after the mold is closed, and after cooling and opening the mold, a block sample of 16* ¹⁶ *1cm can be obtained. .

Example 8 Mix 50g of thermoplastic polyurethane foam beads 6310BM (product specific gravity about 100g/L) with 5g of polyester polyurethane dispersion EP501A, preheat the mold to 125 ^o C, pour the mixed material into 1 cm In a thick square mold, hot-press at 125 ^o C for 0.7 minutes after mold closing, and after cooling and mold opening, a block sample of 16*16*1cm can be obtained, and the sample density is 0.208g/cm ³ .

Example 9 Mix 70 g of thermoplastic polyurethane foamed beads 6315BM with 7.7 g of polyether polyurethane dispersion EP360A, preheat the mold to 135 ^o C, pour the mixed material into a square mold with a thickness of 1 cm, After the mold is closed, heat press at 135 ^o C for 2.2 minutes, and after cooling and opening the mold, a 16*16*1cm block sample can be obtained, and the sample density is 0.277g/cm ³ .

Example 10 Mix 45g of thermoplastic polyurethane foam beads 6315BM (product specific gravity about 130g/L) with 5g of polyether polyurethane dispersion EP501A, preheat the mold to 120 ^o C, and pour the mixed material into a diameter of 7 In the spherical mold of centimeters, hot-press at 120 ^o C for 7 minutes after the mold is closed, and after cooling and opening the mold, a spherical sample with a diameter of 7 centimeters can be obtained, and the sample density is 0.261g/cm ³ .

Comparative Example 1 Hot pressing comparative example without adding PUD [thinner thickness]: the mold is preheated to 135 ^o C, and 47 g of thermoplastic polyurethane foam beads 6315BM (product specific gravity is about 130 g/L) are poured into a square shape with a thickness of 0.7 cm In the mold, hot-press at 130 ^o C for 2 minutes after closing the mold, and after cooling and opening the mold, a block sample of 16*16*0.7cm can be obtained. The sample density is 0.261g/cm ³ . The finished product is formed, but the structure is loose. In addition, when the particles are poured into the mold, they are too loose to be filled and difficult to fill uniformly, which is unfavorable for processing.

Comparative Example 2 Hot pressing comparative example without adding PUD [same thickness as the example]: the mold was preheated to 135 ^o C, and 67 g of thermoplastic polyurethane foam beads 6315BM (the product specific gravity was about 130 g/L) was poured into a 1 cm thick In the square mold, hot-press at 130 ^o C for 2 minutes after the mold is closed. After cooling and opening the mold, the foamed beads cannot be formed into square blocks.

Comparative Example 3 Hot pressing comparative example mixed with oily PU: Mix 67g of thermoplastic polyurethane foam beads 6315BM (product specific gravity about 130g/L) with 6.7g of oily polyester polyurethane 98NH, preheat the mold to 135 ^o C, Pour the mixed mixed material into a 1 cm thick square mold, press at 130 ^o C for 2 minutes after the mold is closed, and after cooling and opening the mold, a block sample of 16*16*1cm can be obtained, and the sample density is 0.26 g/cm ³ . Because the drying time of oily PU is short, the hybrid material is prone to agglomeration and cannot be uniformly dispersed in the mold, so it is unfavorable for processing.

Comparative Example 4 Hot pressing with water mixed: Mix 80 g of thermoplastic polyurethane foam beads 6315BM (product specific gravity about 130 g/L) with 8 g of pure water, preheat the mold to 135 ^o C, and mix the mixed material. Pour it into a square mold with a thickness of 1 cm, press it at 130 ^o C for 5 minutes after the mold is closed, and after cooling and opening the mold, a block sample of 16*16*1cm can be obtained, and the sample density is 0.31g/cm ³ . The mixed material is too loose and not easy to be filled, so it is unfavorable for processing.

Comparative Example 5 Hot pressing of secondary chemical microsphere foamed TPU mixed with PUD Comparative example: First, thermoplastic polyurethane 3085AU (produced by Dadong Resin) and foamed microspheres Expancel® 93MB120 (produced by Akzo Nobel) were mixed through a mixer to mix The mixing ratio is 90:10, and the mixing temperature is controlled at 125 ^o C to prevent foaming due to excessively high temperature. The mixed material is stretched and granulated through a single-screw extruder to obtain foamable thermoplastic polyurethane beads. The bead density was 0.559 g/cm ³ . Mix 62 g of thermoplastic polyurethane foamable beads (8593MB) prepared above with 6.2 g of polyester polyurethane dispersion EP501A, preheat the mold to 150 ^o C, and pour the mixed material into a 1 cm thick square. In the mold, hot-press at 150 ^o C for 30 minutes after the mold is closed, and after cooling and opening the mold, a block sample of 16*16*1cm can be obtained, and the sample density is 0.25g/cm ³ .

Comparative Example 6 Steam forming comparative example: The thermoplastic polyurethane foamed beads 6315BM (product specific gravity is about 130g/L) are drawn into the mold through the steam forming equipment to be formed. Before the material is drawn, the mold will be pre-clamped, but reserved The gap is filled with material, the mold filling gap is set to ^11mm , the mold is closed after the material is drawn, and steam is introduced for heating after the mold is closed. , and then the mold is fixed and moved for 5 seconds, and then cooling water is introduced for cooling. The cooling water introduction time is set to 2 minutes. After cooling, the mold is opened, and a 16*16*1cm square plate sample can be obtained. The sample density was 0.26 g/cm ³ .

Comparative Example 7 Steam forming comparative example: The thermoplastic polyurethane foamed beads 6315BM (product specific gravity is about 130g/L) are drawn into the mold through the steam forming equipment to be formed. Before the material is drawn, the mold will be pre-clamped, but reserved The gap is filled with material, the mold filling gap is set to ^13mm , the mold is closed after the material is drawn, and steam is introduced for heating after the mold is closed. Seconds, after that, the mold is fixed and moved for 5 seconds, and then cooling water is introduced for cooling. The cooling water introduction time is set to 2 minutes. After cooling, the mold is opened, and a 16*16*1cm square plate sample can be obtained. The sample density was 0.277 g/cm ³ .

Comparative Example 8 Steam forming comparative example [particles with lighter specific gravity, comparative example 8]: The thermoplastic polyurethane foam beads 6310BM (product specific gravity about 100g/L) are drawn into the mold through the steam forming equipment to be formed. , the mold will be pre-clamped, but a gap will be reserved for material filling. The mold filling gap is set to 11mm. After the material is drawn, the mold is closed. After the mold is closed, steam is introduced for heating. The steam pressure is set to 0.7bar, and the internal temperature is about 115 ^o C, the steam introduction time is set to 20 seconds, then the mold is fixed and moved for 5 seconds, and then cooling water is introduced for cooling, the cooling water introduction time is set to 2 minutes, and the mold is opened after cooling to obtain a 16*16*1cm square plate sample. The sample density was 0.236 g/cm ³ .

Density Measurement The density (g/cm ³ ) of the ETPU molded article was obtained by measuring according to ISO 845. According to the ISO 845 specification, at least five samples of the same foamed product are taken. After measuring the volume and weight of the foamed molded product, the sample density can be obtained by dividing the sample weight by the volume.

Hardness measurement According to the method of JIS S 6050, the hardness (Asker C) of the ETPU molded product was obtained. Use a hardness tester TECLOCK GS-701N that conforms to JIS S 6050, press it horizontally on the surface of the sample, and directly read the pointer scale to get the surface hardness.

Resilience measurement According to the specification of DIN 53512, the rebound rate (%) of the obtained ETPU moldings was determined. The measurement method of rebound rate (%) is to place the ETPU molded product in the test position of the pendulum rebound tester. The length and width of the measured sample should be greater than 50mm, the thickness should be greater than 15mm, and the thickness should be less than 15mm. Lamination testing is allowed. The test pendulum head falls freely from 90 degrees, and the value displayed by the pointer of the rebound tester is the rebound rate (%) of the ETPU molded product.

Tensile strength and elongation measurement According to ISO 1798, the tensile strength (kg/cm ² ) and elongation % of the ETPU molded article were obtained. The test is carried out according to the ISO 1798 standard method, and the high-speed rail GOTECH universal tensile machine TCS-2000-U is used for the test. The sample pellets are prepared into Type 1A dumbbell-shaped test pieces for the test. The tensile strength can be divided by the maximum force measured. Obtained as cross-sectional area; elongation can be calculated from the length before tensile fracture (L) minus the original sample length (L ₀ ) divided by the original sample length (L ₀ ).

Table 1 shows the experimental conditions and evaluation results of Examples 1 to 10 and Comparative Examples 1 to 8 according to the method of the present invention.

thermoforming ETPU beads PUD ETPU specific gravity PUD add scale Sample thickness mold temperature Product Density [ISO 845] Product hardness [JIS S 6050] Product springback [DIN 53512] Tensile strength [ISO 1798] Elongation [ISO 1798] unit g/L phr cm °C g/cm ³ Asker C % kg/cm ² % Example 1 6315BM EP501A 130 11 1.5 135 0.263 34 63 15.78 185.26 Example 2 6315BM EP501A 130 3 1 135 0.273 35 63 7.75 71.35 Example 3 6315BM EP501A 130 5 1 135 0.275 35 63 11.96 107.72 Example 4 6315BM EP501A 130 7 1 135 0.277 36 63 13.17 169.19 Example 5 6315BM EP501A 130 10 1 135 0.281 36 63 16.28 206.67 Example 6 6315BM EP501A 130 10 1 105 0.282 35 63 14.93 154.66 Example 7 6315BM EP501A 130 10 1 80 0.281 35 63 8.04 69.287 Example 8 6310BM EP501A 100 10 1 125 0.208 30 64 10.84 153.9 Example 9 6315BM EP360A 130 11 1 135 0.277 34 63 12.60 241.33 Example 10 6315BM EP501A 130 11 R7 120 0.261 34 63 -- -- Comparative Example 1 6315BM no addition 130 -- 0.7 130 0.261 34 62 1.48 15.33 Comparative Example 2 6315BM no addition 130 -- 1 130 cannot be formed -- -- -- -- Comparative Example 3 6315BM substituted with 98NH 130 10 1 130 0.26 40 62 1.18 13.21 Comparative Example 4 6315BM replaced with water 130 10 1 130 0.31 33 62 4.5 41.32 Comparative Example 5 8593MB EP501A 559 10 1 150 0.25 65 44 6.5 20 steam forming ETPU PUD ETPU specific gravity vapor breakthrough temperature Product Density [ISO 845] Product hardness [JIS S 6050] Product springback [DIN 53512] Tensile strength [ISO 1798] Elongation [ISO 1798] unit g/L °C g/cm ³ Asker C % kg/cm ² % Comparative Example 6 6315BM no addition 130 120 0.26 35 62 8.83 122 Comparative Example 7 6315BM no addition 130 123 0.277 36 62 10.46 142 Comparative Example 8 6310BM no addition 100 115 0.236 29 61 5.62 130 Table 1

As shown in Table 1, Comparative Example 1 does not use PUD and directly heats ETPU. Even though the thickness of the molded product is only 0.7 cm, the tensile strength of the molded product is still significantly lower than that obtained by the method of the present invention. molding. Also as mentioned above, the molded article of Comparative Example 1 has a loose structure. Accordingly, the mechanical properties of the molded product obtained by directly thermoforming ETPU without using PUD obviously cannot reach an acceptable level. Similarly, in Comparative Example 2, ETPU was directly thermoformed without using PUD. When the thickness of the product to be formed reaches 1 cm, it cannot be formed. In Comparative Example 3, oily PU and ETPU were used for thermoforming. In addition to the difficulty in processing the mixture, the tensile strength of the molded product was significantly lower than that of the molded product obtained by the method of the present invention. In Comparative Example 4, although water and ETPU can be used for hot pressing, the mechanical strength of the molded product is poor, that is, the density is high and the tensile strength is low. Comparative Example 5 Although the TPU and PUD foamed with secondary chemical microspheres can also be used for hot pressing, the heating time is longer, and the mechanical strength of the molded product is poor, that is, the hardness of the molded product is significantly higher than that of the PUD. high, and the resilience and tensile strength are also poor. Comparative Examples 6 to 8 are control groups for directly processing ETPU by steam molding to obtain ETPU molded products.

According to the above, according to the method of the present invention, the industry does not need to purchase additional steam molding equipment and can use the existing hot pressing molding equipment to produce ETPU moldings with a thickness above a certain thickness. In addition, the ETPU and PUD mixture used in the present invention facilitates processing. The ETPU molded article produced according to the present invention can maintain good or even better mechanical properties, such as low density, low hardness, good elasticity and tensile strength, and desired elongation ratio. In addition, compared with the traditional steam forming method, the method of the present invention can be processed at a lower temperature by using a hot pressing model, so as to save heating energy.

102: Top surface 104: Underside 106: Side

Figure 1 shows an expanded thermoplastic polyurethane shoe midsole molding according to one embodiment of the present invention.

102: Top surface

104: Underside

106: Side

Claims (16)

A method of manufacturing a foamed thermoplastic polyurethane (ETPU) molded product, comprising the following steps: (i) mixing the expanded thermoplastic polyurethane beads with a polyurethane dispersion (PUD) to obtain a mixture; and (ii) The mixture is placed in a mold for thermocompression molding to obtain an ETPU molded product. The method of claim 1, wherein the thermoforming step is performed at a temperature of about 80 ^° C to about 140 ^° C. The method of claim 1, wherein the amount of the PUD in the mixture is from about 1 phr to about 35 phr. The method of any one of claims 1 to 3, wherein the ETPU molded product has a thickness of more than about 1 cm. The method of any one of claims 1 to 3, wherein the ETPU molded product has a tensile strength of about 6 kg/cm ² or more. The method of any one of claims 1 to 3, wherein the ETPU beads have a diameter of from about 0.5 mm to about 15 mm. The method of any one of claims 1 to 3, wherein the ETPU molded article has a hardness in the range of about 25 to 50 Asker C. The method of any one of claims 1 to 3, wherein the ETPU beads are polyether or polyester thermoplastic polyurethane, polycarbonate thermoplastic polyurethane, polycaprolactone thermoplastic polyurethane, or non-yellowing thermoplastic polyurethane . The method of any one of claims 1 to 3, wherein the ETPU beads have a specific gravity of about 50 g/L to about 250 g/L. The method of any one of claims 1 to 3, wherein the PUD has a solids content of more than 5% to 70%. The method of any one of claims 1 to 3, wherein the PUD is a PUD selected from esters or ethers. An expanded thermoplastic polyurethane molding comprising a foamed structure, wherein the structure comprises a first part and a second part welded to each other, wherein the first part is formed by a plurality of expanded thermoplastic polyurethane (ETPU) hair The bubble structure, the second part is formed from a polyurethane dispersion (PUD). An expanded thermoplastic polyurethane molded article, which is produced according to the method of any one of claims 1 to 11. The molded article of claim 12 or 13, which is used in the form of a square shape, a spherical shape, a shoe midsole, a slipper mold, a sports article, a bicycle airless tire, or a bicycle seat cushion. The molded article of claim 14, in the form of a shoe midsole, comprising a top surface, a bottom surface, and a side surface, the side surface connecting the top surface and the bottom surface and surrounding a foamed structure, wherein the structure comprises mutually welded The first part and the second part, wherein the first part is a foamed structure formed by a plurality of ETPUs, and the second part is formed by PUD. The molded product of claim 12 or 13 has a tensile strength and mechanical strength of about 6 kg/cm ² or more.

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