Easy Flow Thermoplastic Polyurethane (TPU)

Abstract

Described herein is a thermoplastic polyurethane (TPU) composition that is particularly suitable for 3D printing or additive manufacturing techniques. In particular, the present disclosure relates to a TPU composition that has high melt flowability and low viscosity. The present disclosure further provides a filament that includes the TPU composition. The filament is suitable for 3D printing.

Description

[Technical field]

[0001] The present disclosure relates to a thermoplastic polyurethane (TPU) composition that is particularly suitable for 3D printing or additive manufacturing techniques. In particular, the present disclosure relates to a TPU composition that has high melt flowability and low viscosity without significantly affecting the parts printed using the composition. The present disclosure further relates to a filament that includes the TPU composition. The filament is suitable for 3D printing. [Background technology]

[0002] In the background discussion below, reference is made to certain structures and / or methods. However, the following references should not be construed as an admission that these structures and / or methods constitute prior art. Applicants expressly reserve the right to demonstrate that such structures and / or methods do not qualify as prior art. Summary of the Invention [Problem to be solved by the invention]

[0003] Thermoplastic polyurethanes (TPUs) are thermoplastic elastomers that generally consist of block copolymers containing hard and soft segments. Some TPUs, especially the rigid TPUs used in making thin-walled parts and in three-dimensional (3D) printing, have poor flow properties that can make them difficult to process or use in a printer. [Means for solving the problem]

[0004] In the first embodiment, Thermoplastic polyurethane (TPU); and Flow improver of the formula: [ka] (Wherein, R is OR 1 and; R 1may be hydrogen, branched or unbranched C1-C6 alkyl, branched or unbranched C1-C6 alkoxy, or branched or unbranched C1-C6 hydroxyalkyl). A composition comprising:

[0005] In a second embodiment, the composition of embodiment 1 is described, wherein the thermoplastic polyurethane (TPU) is a polyester thermoplastic polyurethane (TPU).

[0006] In a third embodiment, the composition of embodiment 1 is described, wherein the thermoplastic polyurethane (TPU) is a polyether thermoplastic polyurethane (TPU).

[0007] In a fourth embodiment, the composition of any one of the first to third embodiments is described, wherein the flow improver is present in an amount of about 0.1% to about 5% by weight, based on the total weight of the composition.

[0008] In a fifth embodiment, the composition of any one of the first to fourth embodiments is described, wherein the thermoplastic polyurethane (TPU) further comprises a matting agent.

[0009] In a sixth embodiment, a filament comprising the composition of any one of the first to fifth embodiments is described.

[0010] In the seventh embodiment, the filament according to the sixth embodiment is described, wherein the melt viscosity of the filament at 200° C. is 2500 mPa·s to 10000 mPa·s.

[0011] In an eighth embodiment, the filament of embodiment six or seven is described, wherein the peak tensile strength of the filament is between 3500 psi and 4800 psi.

[0012] In a ninth embodiment, the filament of any one of embodiments 6 to 8 is described, wherein the percent elongation of the filament is between 275% and 750%.

[0013] In a tenth embodiment, a 3D printed article comprising the filament of any one of embodiments 6 to 9 is described. [Brief description of the drawings]

[0014] [Figure 1] 1A shows the relationship between viscosity and shear rate for several formulations described in Example 3. FIG. 1B shows the relationship between viscosity and shear rate for several formulations described in Example 3. [Diagram 2] FIG. 2A shows the relationship between the mass of the extruded filament and the printing speed for two formulations described in Example 4. FIG. 2B shows the relationship between the mass of the extruded filament and the printing speed for three formulations described in Example 4. FIG. 2C shows the relationship between the mass of the extruded filament and the printing speed for two formulations described in Example 4. [Diagram 3] FIG. 3A shows a comparison of 3D printed objects made from multiple formulations described in Example 7. FIG. 3B shows a comparison of the interior of a 3D printed object made from multiple formulations described in Example 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] definition Before describing the present invention in further detail, the terms used in this application are defined as follows, unless otherwise stated.

[0016] As used herein, "about" will be understood by those of ordinary skill in the art and will vary to some extent depending on the context in which it is used. If there are uses of the term which are not clear to persons of ordinary skill in the art from the context in which the term is used, "about" will mean up to plus or minus 10% of the particular term.

[0017] The use of "a," "an," "the," and similar reference words in the context of describing elements (particularly in the context of the claims below) are to be construed as including both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The recitation of ranges of values ​​herein is merely intended to serve as a shorthand method of individually referring to each separate value falling within the range, and each separate value is incorporated herein as if set forth individually herein, unless otherwise indicated herein. All methods described herein can be performed in any suitable order, unless otherwise indicated herein or clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein is intended merely to better describe the embodiments, and does not limit the scope of the claims, unless otherwise indicated. No language in this specification should be construed as indicating any non-claimed element as required.

[0018] "Optional" or "optionally" means that the subsequently described circumstance may or may not occur, and the description includes cases where the circumstance occurs and cases where it does not occur.

[0019] The term "predetermined" refers to an element whose identity is known prior to its use.

[0020] Detailed Description of the Invention Before describing the present invention in more detail, it is to be understood that the invention is not limited to particular embodiments described, as these may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.

[0021] Where a range of values ​​is provided, unless the context clearly dictates otherwise, it is understood that each intervening value, to the tenth of the unit of the lower limit, between the upper and lower limits of that range, and any other stated or intervening value within that stated range, is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges, and are also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where one or both of the limits are included in the stated range, ranges excluding either or both of those included limits are also included in the invention.

[0022] In this specification, the term "about" indicates a range of numerical values ​​that precede it. The term "about" is used in this specification to provide literal support for the exact numerical value that it precedes, as well as a numerical value that is close to or approximately the numerical value that it precedes. When determining whether a numerical value is close to or approximately a specifically stated numerical value, the close or non-approximate numerical value may be a numerical value that provides a substantial equivalence to the specifically stated numerical value in the context in which it is presented.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, representative exemplary methods and materials are described.

[0024] As will be apparent to those skilled in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has distinct components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the invention. Any recited method can be carried out in the order of events recited or in any other order which is logically possible.

[0025] The present disclosure provides a composition comprising a thermoplastic polyurethane (TPU) and a melt flow modifier.

[0026] The TPU may comprise a polyether TPU or a polyester TPU. In embodiments, the TPU may be formed from at least one polyisocyanate and at least one polyester polyol, where the polyester polyol is formed from at least one polyhydric alcohol and a mixture of two or more dicarboxylic acids.

[0027] The polyurethanes may contain further components, such as at least one chain extender, or hydrolysis regulator, antioxidant, UV stabilizer, plasticizer, organic or inorganic filler, demolding aid, and also further conventional additives.

[0028] The polyester polyols may have an average functionality in the range of 1.8 to 2.3, more preferably in the range of 1.9 to 2.2, in particular in the range equal to 2. Thus, in a further embodiment, the invention provides a polyurethane based on at least one polyisocyanate and at least one polyester diol, where the polyester diol is based on a mixture of at least one polyhydric alcohol and two or more dicarboxylic acids.

[0029] Suitable molecular weight ranges of the polyester polyols employed for the purposes of the present invention are known per se to those skilled in the art. In a preferred embodiment, the molecular weight of the polyester polyol is in the range of 500 to 4000 g / mol, more preferably in the range of 800 to 3000 g / mol, and most preferably in the range of 1000 to 2500 g / mol.

[0030] Polyester polyols which are particularly suitable for the purposes of the present invention have an OH number in the range from 25 to 230 mg KOH / g, more preferably in the range from 35 to 140 mg KOH / g and most preferably in the range from 40 to 115 mg KOH / g.

[0031] The polyester polyols may be based on polyhydric alcohols. Suitable polyhydric alcohols include, for example, polyhydric aliphatic alcohols, for example aliphatic alcohols having 2, 3, 4 or more OH groups, for example 2 or 3 OH groups. Suitable aliphatic alcohols for the purposes of the present invention include, for example, C2-C12 alcohols, preferably C2-C8 alcohols, most preferably C2-C6 alcohols. It is preferred that the polyhydric alcohols for the purposes of the present invention are diols, suitable diols being known per se to the person skilled in the art.

[0032] Suitable aliphatic C2-C6 diols include, for example, ethylene glycol, diethylene glycol, 3-oxapentane-1,5-diol, 1,3-propanediol, 1,2-propanediol, dipropylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,3-propanediol, and 3-methyl-1,5-pentanediol. More preferably, the polyhydric alcohol is selected from the group consisting of 1,3-propanediol and 1,4-butanediol.

[0033] To increase the functionality of the polyester polyol, alcohols with three or more OH groups can also be used. Examples of alcohols with three or more OH groups include glycerol, trimethylolpropane, and pentaerythritol. It is also possible to use oligomeric or polymeric products with two or more hydroxyl groups. Examples of these include polytetrahydrofuran, polylactones, polyglycerols, polyetherols, polyesterols, or α,ω-dihydroxypolybutadienes.

[0034] The polyester polyols may be based on a mixture of two or more dicarboxylic acids as well as on at least one polyhydric alcohol. The dicarboxylic acids suitable for preparing the polyester polyols are known per se to the person skilled in the art.

[0035] The present invention can utilize a mixture of two or more dicarboxylic acids, for example a mixture of two, three or four dicarboxylic acids. For example, a mixture of two or three different dicarboxylic acids selected from the group of C2-C12 dicarboxylic acids can be used. By C2-C12 dicarboxylic acids, it is meant dicarboxylic acids that are aliphatic, linear or branched, and have 2 to 12 carbon atoms. It is also possible to use dicarboxylic acids, for example C2-C14 dicarboxylic acids, preferably C4-C12 dicarboxylic acids, more preferably C6-10 dicarboxylic acids, in the compositions described herein.

[0036] The dicarboxylic acid or dicarboxylic acids employed for the purposes of the present invention may also be in the form of a carboxylic acid diester or in the form of a carboxylic acid anhydride. Aliphatic and / or aromatic dicarboxylic acids can in principle be employed as dicarboxylic acids.

[0037] The mixing ratio between the dicarboxylic acids employed in the mixture may vary between wide limits for the purposes of the present invention. Expressed in mol % for one or more dicarboxylic acids, this mixing ratio may range from 90:10 to 10:90, more preferably from 80:20 to 20:80, most preferably from 70:30 to 30:70.

[0038] The ratio of the components employed in the polyester TPU compositions described herein can in principle vary between wide limits. This ratio of the components employed is typically expressed by the ratio of NCO groups to OH groups, the OH groups being the sum of the OH groups of the polyester polyol employed, the chain extender and any further additives. The ratio of NCO groups to OH groups in the present invention is, for example, in the range of 0.9 to 1.1, preferably in the range of 0.95 to 1.05.

[0039] The thermoplastic polyurethanes (TPUs) of the present disclosure are prepared by reacting an isocyanate with a polyester polyol, optionally further isocyanate-reactive compounds, and optionally a chain extender, in the presence or absence of a catalyst and / or conventional coagents.

[0040] In an embodiment, the TPU comprises less than 15 mol %, more preferably less than 10 mol %, and even more preferably less than 3 mol %, of aromatic monomers based on the total TPU composition.

[0041] Suitable isocyanates include aromatic, aliphatic, cycloaliphatic and / or araliphatic isocyanates, preferably diisocyanates, such as 2,2'-, 2,4'- and / or 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate (NDI), 2,4- and / or 2,6-tolylene diisocyanate (TDI), diphenylmethane diisocyanate, 3,3'-dimethyldiphenyl diisocyanate, 1,2-diphenylethane ... anate and / or phenylene diisocyanate, tri-, tetra-, penta-, hexa-, hepta- and / or octamethylene diisocyanate, 2-methylpentamethylene 1,5-diisocyanate, 2-ethylbutylene 1,4-diisocyanate, pentamethylene 1,5-diisocyanate, butylene 1,4-diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), isocyanato-4-[(4-isocyanatocyclohexyl)methyl]cyclohexane (H12MDI), 2,6-diisocyanatohexane carboxylic acid esters, 1,4- and / or 1,3-bis(isocyanatomethyl)cyclohexane (HXDI), 1,4-cyclohexane diisocyanate, 1-methyl-2,4- and / or -2,6-cyclohexane diisocyanate and / or 4,4'-, 2,4'- and 2,2'-dicyclohexylmethane diisocyanate, preferably These include 2,2'-, 2,4'- and / or 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate (NDI), 2,4- and / or 2,6-tolylene diisocyanate (TDI), hexamethylene diisocyanate, 1-isocyanato-4-[(4-isocyanatocyclohexyl)methyl]cyclohexane, and / or IPDI, more particularly 4,4'-MDI and / or hexamethylene diisocyanate and / or H12MDI.

[0042] In a further embodiment, the present invention also provides the above polyurethane, wherein the polyisocyanate used in the preparation is selected from the group consisting of 2,2'-, 2,4'- and 4,4'-diphenylmethane diisocyanate (MDI), 2,4- and 2,6-tolylene diisocyanate (TDI), hexamethylene diisocyanate and 1-isocyanato-4-[(4-isocyanatocyclohexyl)methyl]cyclohexane (H12MDI).

[0043] Suitable chain extenders include aliphatic, araliphatic, aromatic and / or cycloaliphatic compounds, preferably difunctional compounds, having a molecular weight of 50 to 499 g / mol, examples of which include alkanediols having 2 to 10 carbon atoms in the alkylene radical, preferably 1,4-butanediol, 1,6-hexanediol and / or di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona- and / or decaalkylene glycols having 3 to 8 carbon atoms, preferably unbranched alkanediols, more particularly 1,3-propanediol and 1,4-butanediol.

[0044] For the purposes of the present invention, the chain extender may be selected from the group consisting of aliphatic C2-C6 diols, more preferably from the group consisting of 1,3-propanediol, 1,4-butanediol and 1,6-hexanediol.

[0045] In a further embodiment, the present invention also provides the above polyurethane, wherein the at least one chain extender is selected from the group consisting of C2 to C6 diols.

[0046] Catalysts suitable for promoting the reaction between the NCO groups of the polyisocyanate and the polyol component are conventional compounds known from the prior art and derivable from the literature. Examples of catalysts suitable in the context of the present invention include tertiary amines such as triethylamine, dimethylcyclohexylamine, N-methylmorpholine, N,N'-dimethylpiperazine, 2-(dimethylaminoethoxy)ethanol, diazabicyclo(2,2,2)octane, and also, more particularly, organometallic compounds such as titanates, iron compounds such as iron(VI) acetylacetonate, tin compounds such as tin diacetate, tin dioctate, tin dilaurate, or tin dialkyl salts of aliphatic carboxylic acids such as dibutyltin diacetate, dibutyltin dilaurate, and the like. The catalyst is usually used in an amount of 0.00001 to 0.1 parts by weight per 100 parts by weight of the polyhydroxy compound.

[0047] In addition to the catalyst, conventional auxiliaries can be added to the structural components, i.e. polyols, isocyanates and chain extenders. Examples include blowing agents, surface-active substances, flame retardants, nucleating agents, lubricants and demolding aids, dyes and pigments, stabilizers, e.g. against hydrolysis, light, heat or discoloration, inorganic and / or organic fillers, reinforcing agents, plasticizers and metal deactivators. The hydrolysis regulators used are preferably oligomeric and / or polymeric aliphatic or aromatic carbodiimides. To stabilize the polyurethanes of the invention against aging, stabilizers are preferably added to the polyurethanes. Stabilizers for the purposes of the invention are additives that protect plastics or plastic mixtures from harmful environmental influences. Examples include primary and secondary antioxidants, thiosynergics, organophosphorus compounds of trivalent phosphorus, hindered amine light stabilizers, UV absorbers, hydrolysis regulators, quenchers and flame retardants. Examples of commercially available stabilizers are described in Plastics Additive Handbook, 5th Edition, edited by H. Zweifel, Hanser Publishers, Munich, 2001, p. 98-p. 136.

[0048] If the polyurethane of the present invention is exposed to thermo-oxidative damage during use, antioxidants can be added. It is preferable to use phenolic antioxidants. Examples of phenolic antioxidants are described in Plastics Additive Handbook, 5th Edition, edited by H. Zweifel, Hanser Publishers, Munich, 2001, pp. 98-107 and p. 116-p. 121. Phenol antioxidants with a molecular weight of more than 700 g / mol are preferred. An example of a preferably used phenolic antioxidant is pentaerythrityl tetrakis(3-(3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl)propionate) (Irganox® 1010) or other high molecular weight condensation products formed from the corresponding antioxidants. Phenolic antioxidants are generally used in concentrations of 0.1% to 5% by weight, preferably 0.1% to 2% by weight, in particular 0.5% to 1.5% by weight, based on the total weight of the polyurethane. It is further preferred to use an amorphous or liquid antioxidant.

[0049] Although the polyurethanes of the present invention, due to their preferred composition, are clearly more stable to UV radiation than polyurethanes plasticized with, for example, phthalates or benzoates, stabilization with phenolic stabilizers alone is often insufficient. For this reason, polyurethanes of the present invention that are exposed to UV radiation are preferably further stabilized with UV absorbers. UV absorbers are molecules that absorb high-energy UV light and dissipate its energy. UV absorbers that are widely used industrially belong to the groups of, for example, cinnamates, diphenyl cyanoacrylates, oxamides (oxanilides), more particularly 2-ethoxy-2'-ethyloxanilide, formamidines, benzylidene malonates, diallyl butadienes, triazines, and benzotriazoles. Examples of commercially available UV absorbers are described in Plastics Additive Handbook, 5th Edition, edited by H. Zweifel, Hanser Publishers, Munich, 2001, pp. 116-122.

[0050] In a preferred embodiment, the UV absorber has a number average molecular weight of more than 300 g / mol, more particularly more than 390 g / mol. Furthermore, the UV absorbers preferably used should have a molecular weight of less than or equal to 5000 g / mol, more preferably less than or equal to 2000 g / mol. The group of benzotriazoles is particularly useful as UV absorbers. Examples of particularly useful benzotriazoles are Tinuvin® 213, Tinuvin® 328, Tinuvin® 571, also Tinuvin® 384 and Eversorb® 82. The UV absorbers are preferably added in an amount of 0.01') / 0 to 5% by weight, more preferably 0.1 to 2.0% by weight, in particular 0.2 to 0.5% by weight, based on the total weight of the polyurethane. In many cases, the above-mentioned UV stabilization based on antioxidants and UV absorbers is still insufficient to ensure good stability of the polyurethanes of the invention against the harmful effects of UV radiation. In this case, preferably, in addition to the antioxidants and UV absorbers, hindered amine light stabilizers (HALS) can be added. Particularly preferred UV stabilization comprises a mixture of a phenolic stabilizer, a benzotriazole and a HALS compound in the above-mentioned preferred amounts. However, it is also possible to use compounds combining the functional groups of the stabilizers, for example di(1,2,2,6,6-pentamethyl-4-piperidyl) 2-butyl-2-(3,5-di-tert-butyl-4-hydroxybenzyl) malonate, a sterically hindered piperidyl hydroxybenzyl condensation product such as Tinuvin® 144.

[0051] Particularly suitable are waxes, which perform important functions in the industrial production of polyurethanes, as well as in their processing. Waxes act as internal and external lubricants, reducing friction, and improve the flow properties of polyurethanes. In addition, they are said to act as release agents, preventing polyurethanes from adhering to the surrounding material (e.g. molds), and as dispersants for other additives, such as pigments and antiblocking agents. Suitable are, for example, fatty acid esters, such as stearic acid esters, montanic acid esters and their metal soaps, as well as fatty acid amides, such as stearylamide and oleic acid amide, or polyethylene waxes. An overview of waxes used in thermoplastics is given in Plastics Additive Handbook, 5th edition, edited by H. Zweifel, Hanser Verlag, Munich, 2001, pp. 443 if., EP-A 308 683, EP-A 670 339 and JP-A 5 163 431.

[0052] It is furthermore possible to add combinations of esters and amides, as described in DE-A 19 607 870, and wax mixtures of montanic acid and fatty acid derivatives (DE-A 196 49 290), as well as hydroxystearylamides, as described in DE 10 2006 009 096 A1.

[0053] A particularly preferred embodiment, in the case of polyurethanes with an optionally reduced tendency to take up and / or release substances, utilizes fatty acids having a number of carbon atoms of 24 to 34 and / or esters and / or amides of these fatty acids, as described in DE-A-19706452, in which the fatty acids and / or their derivatives are used in an amount of 0.001 to 15% by weight, based on the total weight of the polyisocyanate polyaddition product. A further preferred embodiment utilizes a) a reaction product of one or more linear fatty acids with alkylenediamines, and b) a reaction product of 12-hydroxystearic acid with alkylenediamines, and / or c) a reaction product of 12-hydroxystearic acid with one or more linear fatty acids, according to EP-A-1826225. This mixture thus comprises a reaction product of an alkylenediamine with a) and b) and / or c).

[0054] Further details on the above auxiliaries and additives can be obtained from technical literature, for example Plastics Additive Handbook, 5th Edition, edited by H. Zweifel, Hanser Publishers, Munich, 2001. All molecular weights given in this literature are in [g / mol].

[0055] It is also possible to add matting agents to give the printed filaments a micro-roughened surface. Particularly preferred embodiments utilize suitable matting agents, for example inorganic materials such as silica, glass beads, ceria, alumina, magnesia and / or zinc oxide, or polymers that are immiscible with the TPU or undergo phase separation with the TPU during cooling, such as polyacrylate, polyethylene, polystyrene, polytetrafluoroethene, organic waxes, aluminum stearate, calcium stearate, polymethyl methacrylate, or mixtures thereof. It is also possible to use mixtures of inorganic and polymeric matting agents. For the production of the filaments according to the invention, the matting agents can also be used as dry blends or in the form of compounds (masterbatches). It is also possible to add the matting agents directly to the extruder during the filament extrusion process, for example in dissolved form by liquid dosing.

[0056] The matting agent can be present in the composition in an amount of about 0.1% by weight or more, about 1% by weight or more, about 2% by weight or more, about 4% by weight or more, about 6% by weight or more, about 8% by weight or more, about 20% by weight or less, about 18% by weight or less, about 16% by weight or less, about 14% by weight or less, about 12% by weight or less, or any value or range subsumed between these endpoints, based on the total weight of the composition. Particularly preferred embodiments include the matting agent in an amount of 4% to 10% by weight.

[0057] The flow improver may include a compound of formula I: [ka] wherein each R is independently OR 1 , C(O)OR 1 , CO(O)R 1 , NH2, NHR 1 , or NR 1 R 2 It may be;R 1may be hydrogen, branched or unbranched C1-C6 alkyl, branched or unbranched C2-C6 alkenyl, branched or unbranched C2-C6 alkynyl, branched or unbranched C1-C6 alkoxy, branched or unbranched C1-C6 hydroxyalkyl, substituted or unsubstituted C3-C8 cycloalkyl, substituted or unsubstituted phenyl, or substituted or unsubstituted heteroaryl; R 2 may be hydrogen, branched or unbranched C1-C6 alkyl, branched or unbranched C2-C6 alkenyl, branched or unbranched C2-C6 alkynyl, substituted or unsubstituted C3-C8 cycloalkyl, substituted or unsubstituted phenyl, or substituted or unsubstituted heteroaryl.

[0058] The flow improver can be present in the composition in an amount of about 0.1% by weight or more, about 0.5% by weight or more, about 1% by weight or more, about 2% by weight or more, about 3% by weight or less, about 4% by weight or less, about 5% by weight or less, based on the total weight of the composition, or any value or range subsumed within these endpoints.

[0059] The flow improver can also be used for the production of the filaments according to the invention as a dry blend or in the form of a compound (masterbatch).It is also possible to add the flow improver directly to the extruder during the extrusion process of the filaments, for example in dissolved form by liquid dosing.

[0060] Modification of TPU with flow improvers has been shown to reduce the softening temperature and increase the melt flow rate. Flow improvers can also reduce the viscosity of the TPU composition. Interestingly, the room temperature properties of the TPU composition are minimally affected by the addition of flow improvers. Without wishing to be bound by theory, it is believed that flow improvers interfere with the formation of intermolecular hydrogen bonds in TPU. Alternatively, or additionally, flow improvers may be incorporated into the hydrogen bond network as acceptors / donors. Thus, flow improvers can increase the flowability of the composition.

[0061] Due to the improved processability, the compositions of the present disclosure are suitable for use in applications such as, for example, the production of TPU filaments, 3D printing, hot melt TPU, TPU yarns, and the production of thin walled parts.

[0062] Thin walled parts are typically formed from harder grades of TPU. Often these materials are not flowable enough to properly fill the part. Current solutions include heating the material to high temperatures to reduce the viscosity, which can result in material degradation and loss of mechanical properties. However, the compositions of the present disclosure allow harder grades of TPU to flow more easily without significantly affecting the mechanical properties at room temperature. This is a distinct advantage in the production of thin walled parts.

[0063] For applications using TPU hot melts, the improved flow and lower softening temperature of the compositions of the present disclosure may provide the TPU hot melts with better wetting and ultimately improved adhesion.

[0064] As described below, these compositions are used in 3D printing at higher printing speeds, so the use of the compositions disclosed herein significantly reduces production time.Currently used compositions have relatively low melt flow index, so they can be difficult to use at higher printing speeds.Generally, the melting behavior and flow of TPU are considered to be the limiting factor of printing speed.

[0065] Compositions currently used in 3D printing can buckle, thereby blocking the nozzle and disrupting the printing process, especially at high printing speeds. In contrast, the compositions disclosed herein can reduce filament buckling during 3D printing, resulting in fewer interruptions during the printing process.

[0066] The final appearance of a 3D printed object may also be affected by the composition used to produce it. During printing, for example, when moving between objects, the flow of material must be temporarily stopped. Stopping the flow of material can prevent oozing and unwanted accumulation of excess material. This restriction is particularly difficult when printing with TPU, since TPU is a viscoelastic material, resulting in problems with strands of unwanted material appearing, especially at the edges of the object. As discussed further below, the formulations of the present disclosure reduce or eliminate the presence of unwanted excess material between 3D printed objects.

[0067] The compositions of the present disclosure are particularly suitable for use as filaments for 3D printing, which are described in part by physical properties such as, for example, melt viscosity, melt flow index (MFI), tensile strength, and percent elongation at break.

[0068] The melt viscosity of the filaments of the present disclosure, measured at 200° C., may be about 2500 mPa·s or more, about 3000 mPa·s or more, about 3500 mPa·s or more, about 4000 mPa·s or more, about 4500 mPa·s or more, about 5000 mPa·s or more, about 5500 mPa·s or less, about 6000 mPa·s or less, about 6500 mPa·s or less, about 7000 mPa·s or less, about 7500 mPa·s or less, about 8000 mPa·s or less, about 8500 mPa·s or less, about 9000 mPa·s or less, about 9500 mPa·s or less, about 10000 mPa·s or less, or any value or range encompassed by these endpoints.

[0069] The melt flow index (MFI) of the filaments of the present disclosure, as measured at 190° C. / 21.6 kg according to the methods described in ASTM D1238 and ISO 1133, can be about 110 g / 10 min or more, about 115 g / 10 min or more, about 120 g / 10 min or more, about 125 g / 10 min or more, about 130 g / 10 min or less, about 135 g / 10 min or less, about 140 g / 10 min or less, about 145 g / 10 min or less, about 150 g / 10 min or less, about 150 g / 10 min or less, or any value or range subsumed between these endpoints.

[0070] Alternatively, the melt flow index (MFI) of the filaments of the present disclosure measured at 190° C. / 21.6 kg may be about 240 g / 10 min or more, about 245 g / 10 min or more, about 250 g / 10 min or more, about 255 g / 10 min or more, about 260 g / 10 min or more, about 265 g / 10 min or more, about 270 g / 10 min or more, about 275 g / 10 min or more, about 280 g / 10 min or more, about 285 g / 10 min or more, about 290 g / 10 min or more, about The viscosity may be 295 g / 10 min or less, about 300 g / 10 min or less, about 305 g / 10 min or less, about 310 g / 10 min or less, about 315 g / 10 min or less, about 320 g / 10 min or less, about 325 g / 10 min or less, about 330 g / 10 min or less, about 335 g / 10 min or less, about 340 g / 10 min or less, about 345 g / 10 min or less, about 350 g / 10 min or less, about 355 g / 10 min or less, or any value or range subsumed between these endpoints.

[0071] The peak tensile strength of the filaments of the present disclosure can be about 3500 psi or more, about 3600 psi or more, about 3700 psi or more, about 3800 psi or more, about 3900 psi or more, about 4000 psi or more, about 4100 psi or less, about 4200 psi or less, about 4300 psi or less, about 4400 psi or less, about 4500 psi or less, about 4600 psi or less, about 4700 psi or less, about 4800 psi or less, or any value or range subsumed between these endpoints.

[0072] The percent elongation to break of the filaments of the present disclosure can be about 275% or more, about 300% or more, about 325% or more, about 350% or more, about 375% or more, about 400% or more, about 425% or more, about 450% or more, about 475% or more, about 500% or more, about 525% or less, about 550% or less, about 575% or less, about 600% or less, about 625% or less, about 650% or less, about 675% or less, about 700% or less, about 725% or less, about 750% or less, or any value or range subsumed between these endpoints.

[0073] The filaments of the present disclosure can be used in 3D printing to create 3D printed objects with desirable properties. For example, fewer defects are observed in the infill layer when the filaments of the present disclosure are used in 3D printing, compared to currently used formulations. Furthermore, less excess material is left behind during retraction when the filaments of the present disclosure are used in 3D printing, compared to currently used formulations. EXAMPLES

[0074] Example 1: Physical property evaluation Four blends of ester and ether TPUs, with and without flow improvers, were tested for a variety of physical properties, as shown in Table 1 below.

[0075] [Table 1]

[0076] Six formulations using different commercial polyether TPUs were then tested with different amounts of flow improver. In all cases, unlubricated polyether TPUs were used. The results are shown in Table 2 below, where "85A" corresponds to a TPU with a Shore hardness of 85A and "74D" corresponds to a TPU with a Shore hardness of 74D.

[0077] [Table 2]

[0078] Six formulations with different commercial polyester TPUs were then tested using different amounts of flow improver. In all cases, polyester TPUs without added lubricant were used. The results are shown in Table 3 below, where "88A" corresponds to a TPU with a Shore hardness of 88A and "57D" corresponds to a TPU with a Shore hardness of 74D.

[0079] [Table 3]

[0080] Example 2: Melt Flow Index (MFI) Six compositions were prepared containing either polyether TPU or matte grade polyether TPU, matte agent, and different amounts of flow improver. The six compositions were then evaluated for melt flow index (MFI) at 210°C / 10kg. The ingredients and MFI of each formulation are shown in Table 4.

[0081] [Table 4]

[0082] As shown in Table 4, the inclusion of flow improver has a significant effect on MFI, especially when the TPU composition contains a matting agent.

[0083] Example 3: Rheological studies The six formulations were then tested for viscosity and shear rate. As shown in Figures 1A and 1B, the presence of flow improver reduced the viscosity. The presence of flow improver had a greater impact on the formulation of matte grade TPU. The rheograms shown in Figures 1A and 1B show that the presence of flow improver increases the Newtonian plateau.

[0084] Example 4: Extrusion test The printer was tested for extrusion by extruding a fixed amount of filament at different printer speeds and comparing the extruded mass. All measurements were performed in triplicate. The printer was a Prusa i3 MK3, and the extrusion / printing temperature was run at 230°C. Formulations 1 and 4 (without flow improver) were tested, and the extruded mass decreased rapidly with increasing extrusion speed. The difference between the two formulations also increased with increasing speed, with the mass of formulation 4 decreasing faster than that of formulation 1, as shown in Figure 2A. Overall, the extruded mass of formulation 4 was lower than that of formulation 1, reflecting the lower MFI of formulation 4 (58g / 10min vs. 70g / 10min for formulation 1). Furthermore, it is noted that the gap between the theoretical and experimental values ​​increases at higher extrusion speeds, as shown in Figure 2A.

[0085] As shown in FIG. 2B, when the flow improver is included, as in Formulations 5 and 6, a significant increase in extrusion mass was found at higher printing speeds compared to Formulation 4, which does not include a flow improver. As can be seen, the extrusion speed appears to have a limited effect on the extrusion mass in Formulations 5 and 6. There does not appear to be a significant difference between Formulation 5, in which the flow improver is present in an amount of 1 wt. %, and Formulation 6, in which the flow improver is present in an amount of 3 wt. %. The difference between the theoretical and experimental values ​​for Formulations 5 and 6 is very small, as shown in FIG. 2B.

[0086] Formulation 2 was also tested in an extrusion study. As shown in Figure 2C, the flow improver seemed to have less of an effect on Formulation 2 than on Formulations 5 and 6, but a significant increase in extruded mass was found compared to Formulation 1 without the flow improver.

[0087] Interestingly, the soft filaments formed from formulations 1 and 4 buckled easily, whereas the formulations containing the flow improver did not exhibit this problem.

[0088] Example 6: Evaluation of printing speed Five flat squares were printed, each with a height of 2 mm and an area ranging from 20 x 20 mm to 100 x 100 mm. Small surfaces were chosen to limit the maximum printing speed. With larger surface areas comes an increased risk of print failure. Formulations were evaluated based on how much of a surface they could successfully print before failing.

[0089] At 230 °C and a print speed of 75 mm / s, Formulation 4 failed on the 1 square. When the print speed was reduced to 60% (45 mm / s), Formulation 4 was able to print 4 squares but still failed on the 5 square. In contrast, Formulation 5 was successfully printed on all sides at 230 °C and a print speed of 75 mm / s.

[0090] Example 7: Entrainment test Formulations 4 and 5 were used to evaluate the difference in appearance of 3D printed objects at different retraction distances. Two blocks were printed at 230 °C, a print speed of 60 mm / s, and a retraction speed of 40 mm / s. Retraction distances of 0 mm, 1 mm, 2 mm, and 3 mm were tested. As shown in Figure 3A, there was a clear difference between formulation 4 without flow improver and formulation 5 with 1 wt% flow improver. At a retraction distance of 1 mm, formulation 5 showed acceptable results, and at a distance of 2 mm, it showed perfect results. In contrast, formulation 4 showed the best results at 3 mm.

[0091] Further inspection of the interior printed objects revealed that the block printed using Formulation 4 contained defects in the infill layer, likely due to nozzle clogging from the previous layer, as shown in Figure 3B. In contrast, the interior of the block printed using Formulation 5 exhibited a fully extruded infill layer.

Claims

1. Thermoplastic polyurethane (TPU); and Flow improver of the formula: 【Chemistry 1】 (Wherein, R is OR １ and; R １ is hydrogen, branched or unbranched C １ ~C ６ Alkyl, branched or unbranched C １ ~C ６ Alkoxy, or branched or unbranched C １ ~C ６ hydroxyalkyl) A composition comprising:

2. The composition of claim 1 , wherein the thermoplastic polyurethane (TPU) is a polyester thermoplastic polyurethane (TPU).

3. The composition of claim 1 , wherein the thermoplastic polyurethane (TPU) is a polyether thermoplastic polyurethane (TPU).

4. The method of claim 1 or 2, wherein the flow improver is present in an amount of about 0.1% to about 5% by weight, based on the total weight of the composition.

5. 3. The method of claim 1 or 2, wherein the thermoplastic polyurethane (TPU) further comprises a polystyrene matting agent in an amount of about 4% to about 10% by weight, based on the total weight of the composition.

6. A process for extruding filaments comprising the composition of claim 1 or 2.

7. A filament comprising the composition of claim 1 or 2.

8. The filament according to claim 7, wherein the melt viscosity of the filament at 200°C is 2500 mPa·s to 10000 mPa·s.

9. 8. The filament of claim 7, wherein the peak tensile strength of the filament is from 3500 psi to 4800 psi.

10. 8. The filament of claim 7, wherein the percent elongation of the filament is between 275% and 750%.

11. A method for extruding the filament of claim 7.

12. 10. A method of producing a 3D printed article comprising the filament of claim 7.

13. 8. A 3D printed article comprising the filament of claim 7.

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