Thermoplastic polyurethane resin suitable for melt spinning

Abstract

The present invention discloses a thermoplastic polyurethane resin suitable for melt spinning, which is formed by a reaction mixture through a polymerization reaction. The reaction mixture includes an isocyanate component and a polyol component. The polyol component includes a first polyol and a second polyol. The first polyol has a first number average molecular weight, and the second polyol has a second number average molecular weight, the first number average molecular weight is between 1,000 and 1,500 g / mol, and the second number average molecular weight is between 2,500 and 3,000 g / mol. The resin component formed by the first polyol through a polymerization reaction is defined as a low melting point segment and has a corresponding first melting point. The resin component formed by the second polyol through a polymerization reaction is defined as a high melting point segment and has a corresponding second melting point. The first melting point is between 170°C and 185°C, and the second melting point is between 195°C and 210°C. Thereby, the machine processing temperature required for the thermoplastic polyurethane resin (TPU resin) in a spinning operation is reduced.

Description

Technical Field

[0001] The invention relates to a thermoplastic polyurethane resin, in particular to a thermoplastic polyurethane resin suitable for melt spinning. Background Art

[0002] Thermoplastic polyurethane (TPU) is a kind of environmentally friendly high molecular polymer. Thermoplastic polyurethane can be made into spinning products through a melt spinning process.

[0003] However, in the prior art, during the production of thermoplastic polyurethane resin pellets, some infusible small crystals or coarse particles are inevitably formed.

[0004] Accordingly, in the process of preparing a spun product by melt spinning, the existing thermoplastic polyurethane resin is prone to breakage due to small crystals or coarse particles.

[0005] In terms of producing fine denier specifications, existing thermoplastic polyurethane resins are prone to problems such as floating fibers and difficulty in winding during the melt spinning process.

[0006] Furthermore, the melt flow index (MI) of conventional thermoplastic polyurethane resins varies greatly during the melt spinning process, which easily causes the thickness of the spun products to vary, thereby affecting the physical properties of the products.

[0007] Therefore, the inventors felt that the above defects could be improved, so they devoted themselves to research and applied scientific principles, and finally proposed the present invention which has a reasonable design and effectively improves the above defects. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a thermoplastic polyurethane resin suitable for melt spinning in view of the shortcomings of the prior art.

[0009] In order to solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a thermoplastic polyurethane resin suitable for melt spinning, which is formed by a reaction mixture through a polymerization reaction, and the reaction mixture includes: an isocyanate component; and a polyol component, the polyol component includes a first polyol and a second polyol, the first polyol has a first number average molecular weight, the second polyol has a second number average molecular weight, the first number average molecular weight is between 1,000 and 1,500 g / mol, and the second number average molecular weight is between 2,500 and 3,000 g / mol; wherein, in the thermoplastic polyurethane resin, the first number average molecular weight is between 1,000 and 1,500 g / mol, and the second number average molecular weight is between 2,500 and 3,000 g / mol. In the polyurethane resin, the resin component formed by the first polyol and the isocyanate component through the polymerization reaction is defined as a low melting point segment and has a corresponding first melting point, and the resin component formed by the second polyol and the isocyanate component through the polymerization reaction is defined as a high melting point segment and has a corresponding second melting point, the first melting point is between 170°C and 185°C, the second melting point is between 195°C and 210°C, and the difference between the first melting point and the second melting point is not less than 15°C; wherein a dissolution heat percentage of the low melting point segment is between 20% and 45%, and a dissolution heat percentage of the high melting point segment is between 55% and 80%.

[0010] Preferably, the first melting point is between 175°C and 180°C, the second melting point is between 200°C and 205°C, and a difference between the first melting point and the second melting point is not less than 20°C.

[0011] Preferably, a heat of solution percentage of the low melting point segment is between 30% and 40%, and a heat of solution percentage of the high melting point segment is between 60% and 70%.

[0012] Preferably, the first polyol is a first polyester polyol and is selected from at least one of the material group consisting of: poly(1,4-butylene adipate) ester diol, poly(ethylene adipate) ester diol-1,4-butylene adipate ester diol, and poly(hexane adipate) ester diol; wherein the second polyol is a second polyester polyol and is selected from at least one of the material group consisting of: poly(1,4-butylene adipate) ester diol, poly(ethylene adipate) ester diol-1,4-butylene adipate ester diol, and poly(hexane adipate) ester diol.

[0013] Preferably, when the thermoplastic polyurethane resin is melt-spun, the low melting point segment will melt and soften first, and the low melting point segment will further assist the high melting point segment to further melt and soften; wherein the low melting point segment can reduce a fusion heat of the thermoplastic polyurethane resin, and the fusion heat of the thermoplastic polyurethane resin is between 15 joules / gram and 25 joules / gram.

[0014] Preferably, the reaction mixture further comprises: a chain terminator component, and the chain terminator component is a monohydric alcohol having a boiling point between 210°C and 344°C.

[0015] Preferably, a UV absorber is further added to the thermoplastic polyurethane resin, and the UV absorber is at least one selected from the group consisting of benzotriazoles, benzophenones, and triazines.

[0016] Preferably, a melt index (MI) of the thermoplastic polyurethane resin is between 10 and 25 g / 10 min (215° C.), and a ratio (Mw / Mn) between a weight average molecular weight (Mw) and a number average molecular weight (Mn) of the thermoplastic polyurethane resin analyzed by a gel permeation chromatography (GPC) is between 1.450 and 1.550.

[0017] Preferably, based on 100 parts by weight of the total weight of the reaction mixture, the amount of the isocyanate component is between 45 parts by weight and 50 parts by weight, and the amount of the polyol component is between 35 parts by weight and 40 parts by weight; wherein a weight ratio between the first polyol and the second polyol ranges from 12:24 to 8:26.

[0018] In order to solve the above technical problems, another technical solution adopted by the present invention is to provide a thermoplastic polyurethane resin suitable for melt spinning, characterized in that a polymer chain of the thermoplastic polyurethane resin includes at least one low melting point segment and at least one high melting point segment; wherein the low melting point segment is formed by a first polyol and an isocyanate component through a polymerization reaction, and the high melting point segment is formed by a second polyol and the isocyanate component through the polymerization reaction; wherein the first polyol has a first number average molecular weight, the second polyol has a second number average molecular weight, and the first number average molecular weight is The amount is between 1,000 grams per mole (g / mol) and 1,500 grams per mole, and the second number average molecular weight is between 2,500 grams per mole and 3,000 grams per mole; wherein the low melting point segment has a first melting point, and the high melting point segment has a second melting point, the first melting point is between 170°C and 185°C, the second melting point is between 195°C and 210°C, a difference between the first melting point and the second melting point is not less than 15°C, a heat of solution percentage of the low melting point segment is 20% to 45%, and a heat of solution percentage of the high melting point segment is 55% to 80%.

[0019] The beneficial effects of the present invention are that the thermoplastic polyurethane resin provided by the present invention can be obtained by "the polyol component comprises a first polyol and a second polyol, the first polyol has a first number average molecular weight, the second polyol has a second number average molecular weight, the first number average molecular weight is between 1,000 and 1,500 g / mol, and the second number average molecular weight is between 2,000 and 3,000 g / mol" and "in the thermoplastic polyurethane resin, the resin component formed by the first polyol and the isocyanate component through the polymerization reaction is defined as a low melting point segment and correspondingly has a first Melting point, the resin component formed by the polymerization reaction of the second polyol and the isocyanate component is defined as a high melting point segment and has a corresponding second melting point, the first melting point is between 170°C and 185°C, the second melting point is between 195°C and 210°C, and the difference between the first melting point and the second melting point is not less than 15°C" and "the percentage of heat of dissolution of the low melting point segment is between 20% and 45%, and the percentage of heat of dissolution of the high melting point segment is between 55% and 80%". The technical scheme reduces the machine processing temperature required for the thermoplastic polyurethane resin (TPU resin) in a spinning operation.

[0020] Furthermore, the spun yarn formed by the spinning operation of the present invention is easy to cool and set, and easy to roll up, and the low processing temperature can prevent the thermoplastic polyurethane resin from being over-melted and the viscosity from becoming too low. Accordingly, the problems of broken yarns, floating yarns, and uneven thickness can be improved.

[0021] To further understand the features and technical contents of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are only for reference and description and are not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The test results of differential scanning calorimetry (DSC) of the thermoplastic polyurethane resin according to the embodiment of the present invention are shown in FIG.

[0023] Figure 2 1 is a test result of gel permeation chromatography (GPC) of a thermoplastic polyurethane resin according to an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The following is an explanation of the disclosed embodiments of the present invention through specific embodiments. Those skilled in the art can understand the advantages and effects of the present invention from the contents disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and the details in this specification can also be modified and changed in various ways based on different viewpoints and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are only simple schematic illustrations and are not depicted according to actual dimensions. It is stated in advance. The following embodiments will further explain the relevant technical contents of the present invention in detail, but the disclosed contents are not intended to limit the scope of protection of the present invention.

[0025] It should be understood that, although the terms "first", "second", "third", etc. may be used herein to describe various components or signals, these components or signals should not be limited by these terms. These terms are mainly used to distinguish one component from another component, or one signal from another signal. In addition, the term "or" used herein may include any one or more combinations of the associated listed items depending on the actual situation.

[0026] [Thermoplastic polyurethane resin]

[0027] Thermoplastic polyurethane resin can be made into spun products through a melt spinning process. However, in the prior art, some infusible small crystals or coarse particles are inevitably formed in the process of producing thermoplastic polyurethane resin pellets. Accordingly, in the process of the existing thermoplastic polyurethane resin being made into spun products through melt spinning, it is easy to cause the phenomenon of broken wires due to the small crystals or coarse particles. In terms of making fine denier specifications, the existing thermoplastic polyurethane resin is prone to problems such as floating wires and difficulty in winding during the melt spinning process. Furthermore, the melt flow index (MI) of the existing thermoplastic polyurethane resin varies greatly during the melt spinning process, which easily causes different thicknesses of the spun products, thereby affecting the physical properties of the products.

[0028] In order to solve the technical defects existing in the above-mentioned prior art, an embodiment of the present invention provides a thermoplastic polyurethane resin (TPU resin), and in particular provides a thermoplastic polyurethane resin suitable for melt spinning.

[0029] When the thermoplastic polyurethane resin of the embodiment of the present invention is melt-spun to form a spun product, the problems of broken filaments, floating filaments, and difficulty in winding during the melt spinning process can be effectively improved. Furthermore, the thermoplastic polyurethane resin of the embodiment of the present invention has a small variation in the melt index during the melt spinning process, so the thickness uniformity of the spun product can also be effectively improved, so that the product has good physical properties.

[0030] In order to achieve the above technical objectives, the thermoplastic polyurethane resin of the embodiment of the present invention comprises two or more polyester polyols. Through the design of different structures and molecular weights, the thermoplastic polyurethane resin can have two melting points. The resin is suitable for melt spinning and has good elongation and winding properties.

[0031] More specifically, the thermoplastic polyurethane resin of the embodiment of the present invention is formed by a reaction mixture through a polymerization reaction, wherein the reaction mixture includes an isocyanate component, a polyol component, and a chain terminator component.

[0032] Based on 100 parts by weight of the total weight of the reaction mixture, the amount of the isocyanate component is between 45 parts by weight and 50 parts by weight, the amount of the polyol component is between 35 parts by weight and 40 parts by weight, and the amount of the chain terminator component is between 0.1 parts by weight and 0.5 parts by weight.

[0033] It should be noted that, in this embodiment, although the reaction mixture is not limited, a chain extender component or other auxiliary additive components may be selectively added, and the present invention is not limited thereto.

[0034] Specifically, the isocyanate component is at least one selected from the group consisting of: methylenediphenyl di-isocyanate (MDI), 4,4'-methylene di-cyclohexyl di-isocyanate (H12MDI), and isophorone di-isocyanate (IPDI). The types of the isocyanate materials are merely exemplary, and the present invention is not limited thereto.

[0035] The polyol component comprises: a first polyol and a second polyol. The first polyol and the second polyol are respectively a first polyester polyol and a second polyester polyol. The weight ratio of the first polyol to the second polyol is between 12:24 and 8:26.

[0036] In some embodiments of the present invention, the first polyester polyol is selected from at least one of the material group consisting of: polyadipate-1,4-butylene glycol ester diol, polyadipate-ethylene glycol-1,4-butylene glycol ester diol, and polyadipate-succinate-hexanediol ester diol. Similarly, the second polyester polyol is selected from at least one of the material group consisting of: polyadipate-1,4-butylene glycol ester diol, polyadipate-ethylene glycol-1,4-butylene glycol ester diol, and polyadipate-succinate-hexanediol ester diol. The material types of the above polyols are only exemplary, and the present invention is not limited thereto.

[0037] The material types of the first polyol and the second polyol can be the same or different, and the present invention is not limited thereto. The main difference between the first polyol and the second polyol is that the number average molecular weight (Mn) of the two polyols falls within different numerical ranges.

[0038] It is worth mentioning that poly(1,4-butylene adipate) (PBA) is formed by the polymerization reaction of adipic acid and 1,4-butanediol. Polyethylene-1,4-buthylene adipate glycol is formed by the polymerization reaction of adipic acid, ethylene glycol, and 1,4-butanediol. Poly(1,6-hexamethyleneadipate-succinic acid) is formed by the polymerization reaction of adipic acid, succinic acid, and hexanediol.

[0039] Further, the first polyol has a first number average molecular weight and the second polyol has a second number average molecular weight, the first number average molecular weight is less than the second number average molecular weight, the first number average molecular weight of the first polyol is between 1,000 g / mol and 1,500 g / mol, the second number average molecular weight of the second polyol is between 2,500 g / mol and 3,000 g / mol, and a difference between the first number average molecular weight and the second number average molecular weight is not less than 1,000 g / mol.

[0040] See also Figure 1 As shown, Figure 1 The test results of differential scanning calorimetry (DSC) of the thermoplastic polyurethane resin according to the embodiment of the present invention. It can be seen from the test results that the thermoplastic polyurethane resin according to the embodiment of the present invention has a first melting point (Tm1) and a second melting point (Tm2). Among them, the first melting point (Tm1) is roughly between 170°C and 185°C, and preferably between 175°C and 180°C. The second melting point (Tm2) is roughly between 195°C and 210°C, and preferably between 200°C and 205°C. Specifically, Tm1=179.1°C, and Tm2=202.16°C. Furthermore, the difference between the first melting point and the second melting point is not less than 15°C, and preferably not less than 20°C.

[0041] In the thermoplastic polyurethane resin, the resin component formed by the polymerization reaction of the first polyol has the first melting point (low melting point), and the resin component formed by the polymerization reaction of the second polyol has the second melting point (high melting point). In addition, the resin component having the first melting point accounts for 20% to 45% of the whole, and preferably 30% to 40%; and the resin component having the second melting point accounts for 55% to 80% of the whole, and preferably 60% to 70%.

[0042] It should be noted that the above % unit is the percentage of heat of dissolution. More specifically, the percentage of heat of dissolution is the ratio of the heat of dissolution of the DSC melting curve obtained by measuring the melting peak area (ΔHm) of the thermoplastic polyurethane resin by differential scanning calorimetry (DSC), and is expressed as a percentage. For example, Figure 1 As shown, the resin component (low melting point segment) having the first melting point Tm1 corresponds to a first melting peak area A1. The resin component (high melting point segment) having the second melting point Tm2 corresponds to a second melting peak area A2. The calculation method for the percentage of heat of dissolution of the resin component (low melting point segment) having the first melting point Tm1 is A1 / (A1+A2). The calculation method for the percentage of heat of dissolution of the resin component (high melting point segment) having the second melting point Tm2 is A2 / (A1+A2).

[0043] It is worth mentioning that the thermoplastic polyurethane resin of the embodiment of the present invention can be made into a granular product and is suitable for the melt spinning process. Among them, the resin component with the first melting point (low melting point) can be used to reduce the machine processing temperature required for the spinning operation in the melt spinning process. In the past, the machine processing temperature required for the spinning operation was roughly between 230°C and 240°C. The machine processing temperature required for the spinning operation of this embodiment can be reduced to 215°C to 225°C. Furthermore, the resin component with the second melting point (high melting point) is used to provide the physical properties required for the spinning operation (such as mechanical strength).

[0044] During the spinning operation, the resin component with the first melting point (low melting point) will melt and soften first, and the resin component with the first melting point (low melting point) will further assist the resin component with the second melting point (high melting point) to further melt and soften. The resin component with the first melting point (low melting point) can effectively reduce the heat of fusion (or heat of fusion) required for the thermoplastic polyurethane resin. It is worth mentioning that the heat of fusion required for spinning thermoplastic polyurethane resins in the past was 40 to 50 joules / gram, while the heat of fusion (thermal enthalpy) required for spinning the thermoplastic polyurethane resins of the embodiments of the present invention can be reduced to 15 to 25 joules / gram (e.g. Figure 1 , thermal enthalpy is 18.2 joules / gram).

[0045] The thermoplastic polyurethane resin of the embodiment of the present invention can be designed by the number average molecular weight of the first polyol and the second polyol, and the percentage of the heat of dissolution of the resin component with the first melting point and the resin component with the second melting point in the whole resin, so that the machine processing temperature required for the thermoplastic polyurethane resin (TPU resin) in a spinning operation can be reduced. Furthermore, the spinning product formed by the spinning operation of the embodiment of the present invention is easy to cool and set, and easy to reel, and the low processing temperature can prevent the thermoplastic polyurethane resin from over-melting and the viscosity from becoming too low. Accordingly, the problems of broken silk, floating silk, uneven thickness, etc. can be effectively improved.

[0046] If the design range of the first number average molecular weight of the first polyol is too low (e.g., less than 1,000 g / mol) or the design range of the first melting point Tm1 is too low (e.g., less than 170°C), the spun product formed by the thermoplastic polyurethane resin through the spinning operation is not easy to cool and set, and is therefore not easy to be wound up. On the contrary, if the design range of the first number average molecular weight of the first polyol is too high (e.g., greater than 1,500 g / mol) or the design range of the first melting point Tm1 is too high (e.g., greater than 185°C), the difference between the two melting points of the thermoplastic polyurethane resin will become insignificant, which will not help reduce the machine processing temperature required in the spinning operation.

[0047] If the proportion of the resin component with the first melting point (low melting point) is too low (e.g., less than 20%), the machine processing temperature required for the spinning operation cannot be effectively reduced. If the proportion of the resin component with the first melting point (low melting point) is too high (e.g., greater than 45%), the physical properties required for the thermoplastic polyurethane resin in the spinning operation will be insufficient.

[0048] Specifically, the chain terminator component is a monohydric alcohol having a boiling point between 210° C. and 344° C. For example, the chain terminator component is at least one selected from the group consisting of arachidyl alcohol, stearyl alcohol, and palmitol. The chain terminator component is particularly suitable for use in a melt spinning process.

[0049] The purpose of adding the chain terminator component is to terminate the polymerization reaction after the thermoplastic polyurethane resin reaches a predetermined molecular weight during the polymerization reaction, so as to complete the reaction. Thereby, the molecular weight of the thermoplastic polyurethane resin can be maintained in a stable state, and the molecular weight distribution of the thermoplastic polyurethane resin can become more concentrated. In other words, since the molecular weight of the thermoplastic polyurethane resin can be maintained in a stable state and avoids continuing to climb, the thermoplastic polyurethane resin is less likely to have coarse particles or crystal points.

[0050] It is worth mentioning that in this embodiment, the first polyol and the second polyol are limited to polyester polyol. The thermoplastic polyurethane resin synthesized from polyester polyol has better tensile strength and heat resistance, and the thermoplastic polyurethane resin is not easy to deform.

[0051] If other types of polyols are used, the thermoplastic polyurethane resin may be less suitable for melt spinning. For example, if polyether polyols are used, the heat resistance and physical properties of the thermoplastic polyurethane resin will deteriorate and it will not be suitable for melt spinning. If polycarbonate polyols are used, the manufacturing cost of the thermoplastic polyurethane resin will become too high, it will be easy to crystallize, and it will feel hard.

[0052] In some embodiments of the present invention, a UV absorber is added to the thermoplastic polyurethane resin so that the QUV of the thermoplastic polyurethane resin can reach level 4 or above. The UV absorber is selected from at least one of the material group consisting of benzotriazoles, benzophenones, and triazines, but the present invention is not limited thereto. The amount of the UV absorber added to the thermoplastic polyurethane resin is 0.1wt% to 1.0wt%. The UV absorber is added in a metered manner in the back section of the reaction extruder, which can reduce the cracking of the material during the extrusion process and the failure of the UV absorption function, so the UV absorber does not essentially participate in the polymerization reaction. The UV absorber is only physically mixed in the thermoplastic polyurethane resin.

[0053] Furthermore, in order to make the thermoplastic polyurethane resin of the embodiment of the present invention more suitable for melt spinning process and spinning operation, the thermoplastic polyurethane resin has the following physical properties:

[0054] The thermoplastic polyurethane resin has a melt flow index (MI) between 10 and 25 g / 10 min (215° C.), and preferably between 15 and 20 g / 10 min (215° C.).

[0055] The "melt index" in this application refers to the weight of a thermoplastic polyurethane resin passing through a standard die every 10 minutes on a melt flow anemometer at a temperature of 215°C, and the unit is g / 10min (215°C). The melt index indicates the fluidity of the resin in a molten state. The larger the melt index, the smaller the molecular weight and the better the fluidity.

[0056] The thermoplastic polyurethane resin is analyzed by gel permeation chromatography (GPC) to obtain a ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of 1.450 to 1.550. The “ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn)” is a type of polydispersity index.

[0057] More specifically, see Figure 2 As shown, Figure 2 The test results of the gel permeation chromatography (GPC) of the thermoplastic polyurethane resin according to the embodiment of the present invention are shown in the figure. From the peak information, it can be seen that there is an extremely high peak at about 18 to 20 minutes. In this GPC analysis, the number average molecular weight (Mn) of the thermoplastic polyurethane resin is approximately between 47,000 and 53,000 g / mol, the weight average molecular weight (Mw) of the thermoplastic polyurethane resin is approximately between 72,000 and 78,000 g / mol, and the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is between 1.450 and 1.550, and preferably between 1.470 and 1.530.

[0058] From the perspective of polymer structure, a polymer chain of the thermoplastic polyurethane resin includes randomly distributed: at least one low melting point segment and at least one high melting point segment. The low melting point segment is composed of a residue of a first polyol other than hydroxyl groups, and the high melting point segment is composed of a residue of a second polyol other than hydroxyl groups. The first polyol has a first number average molecular weight, the second polyol has a second number average molecular weight, the first number average molecular weight is less than the second number average molecular weight, the first number average molecular weight of the first polyol is between 1,000 g / mol and 1,500 g / mol, the second number average molecular weight of the second polyol is between 2,500 g / mol and 3,000 g / mol, and the difference between the first number average molecular weight and the second number average molecular weight is not less than 1,000 g / mol. The thermoplastic polyurethane resin has a first melting point and a second melting point. The low melting point segment formed by the polymerization reaction of the first polyol has the first melting point, and the high melting point segment formed by the polymerization reaction of the second polyol has the second melting point. The first melting point is between 170°C and 185°C. The second melting point is between 195°C and 210°C. In addition, the low melting point segment with the first melting point accounts for 20% to 45% of the whole, and the high melting point segment with the second melting point accounts for 55% to 80% of the whole. The above % is the percentage of heat of solution.

[0059] [Method for producing thermoplastic polyurethane resin]

[0060] The above is a description of the characteristics of the thermoplastic polyurethane resin material according to the embodiment of the present invention, and the following will describe the method for manufacturing the thermoplastic polyurethane resin according to the embodiment of the present invention.

[0061] The method for producing the thermoplastic polyurethane resin includes a mixing stage and a reaction stage.

[0062] The mixing stage includes: using a separate metering device, according to the metering described in the embodiment of the present invention, stably introducing the isocyanate component and the polyol component (including the first polyol and the second polyol) into a mixer for premixing to form a reaction mixture.

[0063] The reaction stage comprises: introducing a reaction mixture containing an isocyanate component and a polyol component into a twin-screw reaction extruder to allow the isocyanate component and the polyol component to undergo a polymerization reaction, and introducing a chain terminator component at the rear stage of the reaction extrusion to terminate the polymerization reaction and finally form a thermoplastic polyurethane resin.

[0064] The extrusion temperature of the twin-screw reaction extruder is preferably set between 150° C. and 250° C. to facilitate the polymerization reaction to be fully carried out, but the present invention is not limited thereto. Furthermore, after the reaction extrusion step is completed, the thermoplastic polyurethane resin is pelletized in an aqueous environment to form a granular TPU resin.

[0065] In some embodiments of the present invention, the method for manufacturing the thermoplastic polyurethane resin further monitors the viscosity in real time on a reference line, and feeds back the injection amount of the raw material based on the monitored viscosity value, thereby improving the injection accuracy of the raw material, and can control the NCO / OH equivalent ratio in real time to fall within a predetermined range, thereby obtaining a TPU resin with a stable melt index change rate within a batch. More specifically, after the reaction mixture comes out of a separate meter, the real-time viscosity can be detected by an online viscometer. When the viscosity exceeds the control range, the raw material metering amount is adjusted and the viscosity is corrected to ensure stable production.

[0066] In addition, the NCO / OH equivalent ratio of the reaction mixture in the polymerization reaction is preferably controlled to be between 0.98 and 1.02, and particularly preferably controlled to be between 0.995 and 1.005, but the present invention is not limited thereto.

[0067] [Experimental data test]

[0068] Hereinafter, the contents of the present invention are described in detail with reference to Examples 1 to 4 and Comparative Examples 1 to 2. However, the following examples are only used to help understand the present invention, and the scope of the present invention is not limited to these examples. The experimental conditions and test results of Examples 1 to 4 and Comparative Examples 1 to 2 are shown in Table 1. Among them, Examples 1 to 4 are preferred embodiments of the present invention, and Comparative Examples 1 to 2 are control groups, which are used to prove that Examples 1 to 4 have better technical effects.

[0069] Next, the thermoplastic polyurethane resins prepared in Examples 1 to 4 and Comparative Examples 1 to 2 were tested for physical and chemical properties to obtain the physical and chemical properties of the thermoplastic polyurethane resins, such as: first melting point Tm1 (°C), second melting point Tm2 (°C), Mw / Mn, melt index (g / 10min (215°C)), and heat of fusion (J / g). The relevant test methods have been described above, and the test results are summarized in Table 1 below.

[0070] [Table 1 Experimental conditions and test results]

[0071]

[0072] [Test results discussion]

[0073] In the embodiment, two polyols are introduced, the first melting point temperature of the TPU rubber particles is between 175 and 181°C, and the second melting point temperature is between 195 and 202°C. The TPU rubber particles are processed by melt spinning to have the advantages of no floating filaments and good fluidity, and can be continuously produced for more than 48 hours with good spinning conditions.

[0074] In the comparative example, the first melting point temperature of the TPU rubber particles is between 185 and 190° C., and the second melting point temperature is between 204 and 210° C. The melting point of the TPU rubber particles is too high, resulting in rapid crystallization, easy crystallization, pressure rise and easy fiber breakage during the melt spinning process.

[0075] [Beneficial Effects of Embodiments]

[0076] The thermoplastic polyurethane resin provided in an embodiment of the present invention can be obtained by: "the polyol component includes a first polyol and a second polyol, the first polyol has a first number average molecular weight, the second polyol has a second number average molecular weight, the first number average molecular weight is between 1,000 and 1,500 g / mol, and the second number average molecular weight is between 2,500 and 3,000 g / mol" and "in the thermoplastic polyurethane resin, the resin component formed by the first polyol and the isocyanate component through the polymerization reaction is defined as a low melting point segment and has a first melting point, The resin component formed by the polymerization reaction of the second polyol and the isocyanate component is defined as a high melting point segment and has a corresponding second melting point, the first melting point is between 170°C and 185°C, the second melting point is between 195°C and 210°C, and the difference between the first melting point and the second melting point is not less than 15°C" and "the percentage of heat of dissolution of the low melting point segment is between 20% and 45%, and the percentage of heat of dissolution of the high melting point segment is between 55% and 80%". The technical scheme reduces the machine processing temperature required for the thermoplastic polyurethane resin (TPU resin) in a spinning operation.

[0077] Furthermore, the spinning product formed by the spinning operation of the embodiment of the present invention is easy to cool and set, and easy to reel, and the low processing temperature can prevent the thermoplastic polyurethane resin from over-melting and the viscosity from becoming too low. Accordingly, the problems of broken wires, floating wires, and uneven thickness can be effectively improved.

[0078] The contents disclosed above are only preferred feasible embodiments of the present invention, and are not intended to limit the scope of the present invention. Therefore, all equivalent technical changes made using the contents of the present invention's specification and drawings are included in the scope of the present invention.

Claims

1. A thermoplastic polyurethane resin suitable for melt spinning, characterized in that: The thermoplastic polyurethane resin is formed from a reaction mixture via a polymerization reaction, and the reaction mixture includes: an isocyanate component; wherein the isocyanate component is 4,4'-diphenylmethane diisocyanate; and a polyol component, the polyol component being composed of a first polyol and a second polyol, the first polyol having a first number average molecular weight, the second polyol having a second number average molecular weight, the first number average molecular weight being 1,000 g / mol, and the second number average molecular weight being 2,000 g / mol; wherein the first polyol is a first polyester polyol, and the second polyol is a second polyester polyol; Wherein, in the thermoplastic polyurethane resin, the resin component formed by the polymerization reaction of the first polyol and the isocyanate component is defined as a low melting point segment and has a first melting point, and the resin component formed by the polymerization reaction of the second polyol and the isocyanate component is defined as a high melting point segment and has a second melting point, the first melting point is between 170°C and 181°C, the second melting point is between 195°C and 202°C, and the difference between the first melting point and the second melting point is not less than 15°C; Wherein, a heat of solution percentage of the low melting point segment is between 20% and 45%, and a heat of solution percentage of the high melting point segment is between 55% and 80%; Wherein, the heat of dissolution percentage is obtained by measuring the thermoplastic polyurethane resin via differential scanning calorimetry; wherein the resin component having the first melting point is the low melting point segment, corresponding to a first melting peak area obtained by differential scanning calorimetry, defined as A1; the resin component having the second melting point is the high melting point segment, corresponding to a second melting peak area obtained by differential scanning calorimetry, defined as A2; wherein the heat of dissolution percentage of the low melting point segment is A1 / (A1+A2), and the heat of dissolution percentage of the high melting point segment is A2 / (A1+A2); The thermoplastic polyurethane resin has a heat of fusion ranging from 15 J / g to 18.5 J / g.

2. The thermoplastic polyurethane resin according to claim 1, characterized in that The difference between the first melting point and the second melting point is not less than 20°C.

3. The thermoplastic polyurethane resin according to claim 1, characterized in that The first polyester polyol is selected from at least one of the material group consisting of: poly(1,4-butylene adipate) ester diol, poly(ethylene adipate) ester diol-1,4-butylene adipate ester diol, and poly(hexane adipate) ester diol; wherein the second polyester polyol is selected from at least one of the material group consisting of: poly(1,4-butylene adipate) ester diol, poly(ethylene adipate) ester diol-1,4-butylene adipate ester diol, and poly(hexane adipate) ester diol.

4. The thermoplastic polyurethane resin according to claim 1, characterized in that The reaction mixture further comprises: a chain terminator component, and the chain terminator component is a monohydric alcohol having a boiling point between 210°C and 344°C.

5. The thermoplastic polyurethane resin according to claim 1, characterized in that The thermoplastic polyurethane resin is further added with an ultraviolet absorber, and the ultraviolet absorber is at least one selected from the material group consisting of benzotriazoles, benzophenones, and triazines.

6. The thermoplastic polyurethane resin according to claim 1, characterized in that Based on the total weight of the reaction mixture being 100 parts by weight, the amount of the isocyanate component used is between 45 parts by weight and 50 parts by weight, and the amount of the polyol component used is between 35 parts by weight and 40 parts by weight; wherein a weight ratio between the first polyol and the second polyol ranges from 12:24 to 8:

26.

7. A thermoplastic polyurethane resin suitable for melt spinning, characterized in that: A polymer chain of the thermoplastic polyurethane resin includes at least one low melting point segment and at least one high melting point segment; The low melting point segment is formed by a polymerization reaction between a first polyol and an isocyanate component, and the high melting point segment is formed by a polymerization reaction between a second polyol and the isocyanate component; wherein the isocyanate component is 4,4'-diphenylmethane diisocyanate; wherein the first polyol has a first number average molecular weight, the second polyol has a second number average molecular weight, the first number average molecular weight is 1,000 g / mol, and the second number average molecular weight is 2,000 g / mol; wherein the first polyol is a first polyester polyol, and the second polyol is a second polyester polyol; The low melting point segment has a first melting point, and the high melting point segment has a second melting point. The first melting point is between 170°C and 181°C, and the second melting point is between 195°C and 202°C. The difference between the first melting point and the second melting point is not less than 15°C. The heat of solution of the low melting point segment is between 20% and 45%, and the heat of solution of the high melting point segment is between 55% and 80%. The heat of solution is obtained by measuring the thermoplastic polyurethane resin by differential scanning calorimetry. Wherein, the resin component having the first melting point is the low melting point segment, corresponding to a first melting peak area obtained by differential scanning calorimetry, defined as A1; the resin component having the second melting point is the high melting point segment, corresponding to a second melting peak area obtained by differential scanning calorimetry, defined as A2; wherein the percentage of the heat of solution of the low melting point segment is A1 / (A1+A2), and the percentage of the heat of solution of the high melting point segment is A2 / (A1+A2); The thermoplastic polyurethane resin has a heat of fusion ranging from 15 J / g to 18.5 J / g.

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