Polyurethane composition

Abstract

A polyurethane composition comprising from 50% to 98% by weight, based on the total weight of the polyurethane composition, of an isocyanate component, the isocyanate component comprising: from 7% to 55% by weight, based on the total weight of the isocyanate component, of a first isocyanate terminated prepolymer derived from a siloxane-caprolactone block copolymer polyol; and from 45% to 93% by weight, based on the total weight of the isocyanate component, of a diisocyanate-terminated prepolymer derived from a polyester polyol. The polyurethane composition further comprises from 2% to 50% by weight, based on the total weight of the polyurethane composition, of an isocyanate reactive component, the isocyanate reactive component comprising a chain extender.

Description

Technical Field

[0001] The present disclosure relates to a polyurethane composition, and more particularly to a two-component polyurethane composition. Background Art

[0002] Polyurethane is used in the world and can be produced as the reaction product of isocyanate reactive compound and isocyanate. Many applications of polyurethane (such as synthetic leather) may require high strength, high elongation at break and low thermal conductivity. However, it is challenging to produce such polyurethane. Existing reports on ductility and strengthening of polyurethane are limited to the use of nanofillers. For example, it is reported that nanofillers based on melanin, cellulose or graphene oxide (GO) bring high strength and high elongation at break to polyurethane. However, many nanofillers are dark in color, difficult to store and handle on a large scale, and can cause environmental concerns about particulate matter released during the life cycle, which limits their application. Therefore, it is necessary to provide a polyurethane composition with high strength, high elongation at break and low thermal conductivity. Summary of the invention

[0003] In one aspect, a polyurethane composition comprises 50 to 98 wt% of an isocyanate component based on the total weight of the polyurethane composition, the isocyanate component comprising: 7 to 55 wt% of a first isocyanate-terminated prepolymer derived from a siloxane-caprolactone block copolymer polyol, based on the total weight of the isocyanate component; and 45 to 93 wt% of a second isocyanate-terminated prepolymer derived from a polyester polyol, based on the total weight of the isocyanate component. The polyurethane composition also comprises 2 to 50 wt% of an isocyanate-reactive component, based on the total weight of the polyurethane composition, the isocyanate-reactive component comprising a chain extender. DETAILED DESCRIPTION

[0004] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the invention belongs. In addition, all publications, patent applications, patents and other references mentioned herein are incorporated by reference. As disclosed herein, "and / or" means "and, or as an alternative". Unless otherwise specified, all ranges include endpoints. Unless otherwise specified, as disclosed herein, all percentages mentioned herein are by weight and temperatures are in ° C.

[0005] Polyurethane composition

[0006] On the one hand, the present disclosure provides a kind of polyurethane composition, and the polyurethane composition comprises the blend of isocyanate-terminated prepolymer. The polyurethane composition is a two-component composition. As used herein, the term "two-component" means that the composition is provided in parts separated from each other before reacting them. For example, the isocyanate component and the isocyanate-reactive component of the composition can be prepared, stored, transported and supplied separately, and soon or immediately combined, for example, in a mixer, to form a reactive mixture. It is considered that when the two components are in contact, the curing reaction begins, wherein the isocyanate-reactive groups react with the isocyanate groups to form a cured composition. The reactive polyurethane composition formed by contacting the two components can be referred to as a "reactive liquid intermediate" or a "reactive mixture".

[0007] The mixing ratio between the isocyanate component and the isocyanate reactive component is not strictly limited. The polyurethane composition can have an isocyanate index of 0.60 to 1.80 (e.g., 0.80 to 1.50, 0.90 to 1.20, etc.), which is measured as [active isocyanate groups / active hydrogen groups]. The isocyanate index is defined as the molar stoichiometric excess of the isocyanate moiety in the reaction mixture relative to the mole number of isocyanate reactive units (active hydrogens that can be used to react with the isocyanate moieties). An isocyanate index of 1.00 means no stoichiometric excess, so that there is 1.0 mole of isocyanate groups per 1.0 mole of isocyanate reactive groups. The polyurethane composition can be described as solvent-free.

[0008] The polyurethane composition may include 50 to 98 wt % (e.g., 60 to 98 wt %, 70 to 98 wt %, 80 to 98 wt %, 90 to 98 wt %, etc.) of an isocyanate component, based on the total weight of the polyurethane composition. The polyurethane composition may include 2 to 50 wt % (e.g., 2 to 40 wt %, 2 to 30 wt %, 2 to 20 wt %, 2 to 10 wt %, etc.) of an isocyanate reactive component, based on the total weight of the polyurethane composition.

[0009] For embodiments, the isocyanate component comprises a blend of isocyanate-terminated prepolymers (also referred to as polyurethane prepolymers) which can be converted to the final product by reaction with an isocyanate-reactive component comprising at least a chain extender. Each isocyanate-terminated prepolymer can be prepared by reacting a polyisocyanate with a polyol moiety to form a polymer having urethane linkages and at least one terminal isocyanate (NCO) group.

[0010] Isocyanate component

[0011] In one aspect, the isocyanate component provides a blend of at least two different isocyanate (NCO) terminated prepolymers. The isocyanate terminated prepolymers can be prepared, packaged, stored and transported as independent products. The isocyanate terminated prepolymers can have low viscosity, can be moisture resistant (hydrophobic) and storage stable.

[0012] The first isocyanate-terminated prepolymer is derived from a siloxane-caprolactone block copolymer polyol, so that it is a reaction product of a polyisocyanate and a siloxane-caprolactone block copolymer polyol. The second isocyanate-terminated prepolymer is derived from a polyester polyol, so that it is a reaction product of a polyisocyanate and a polyester polyol. Based on the gross weight of the isocyanate component, the isocyanate component comprises 7 to 55 wt % (e.g., 8 to 52 wt %, 10 to 40 wt %, 10 to 30 wt %, 10 to 25 wt %, 15 to 25 wt %, etc.) of the first isocyanate-terminated prepolymer. The isocyanate component comprises 45 to 93 wt % (e.g., 48 to 92 wt %, 50 to 90 wt %, 60 to 90 wt %, 70 to 90 wt %, 75 to 85 wt %, etc.) of the second isocyanate-terminated prepolymer, based on the total weight of the isocyanate component. The weight ratio of the first isocyanate-terminated prepolymer to the second isocyanate-terminated prepolymer can be >5:95 and <60:40 (e.g., 7:93, 8:92, 9:91, or 10:90, 15:85 to 25:75, 40:60, 45:55, 50:50, or 55:45).

[0013] The polyisocyanate may be an aromatic isocyanate, an aliphatic isocyanate, a carbodiimide-modified isocyanate compound, and modifications / isomers / combinations thereof. Examples include, for example, diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), xylene diisocyanate (XDI), and methylene biscyclohexyl isocyanate (HMDI).

[0014] The isocyanate component can consist essentially of (e.g., consist of) a first isocyanate-terminated prepolymer and a second isocyanate-terminated prepolymer. The weight ratio of the first isocyanate-terminated prepolymer to the second isocyanate-terminated prepolymer can be >5:95 and <60:40, such as 7:93, 8:92, 9:91, or 10:90, 15:85 to 25:75, 40:60, 45:55, 50:50, or 55:45.

[0015] The first isocyanate-terminated prepolymer is derived from a siloxane-caprolactone block copolymer polyol, such that it is the reaction product of a polyisocyanate and a siloxane-caprolactone block copolymer polyol. Siloxane-caprolactone block copolymer polyol means a copolymer having at least one siloxane block and a caprolactone (e.g., polymerized caprolactone) block. Caprolactone means a polyisocyanate having the formula C6H 10 O2 seven-membered ring, which may also be referred to as ε-caprolactone and / or hexane-6-lactone. For example, a siloxane having at least two terminal hydroxyl groups may act as an initiator (e.g., forming a midblock), such that caprolactone is added to the initiator via a ring-opening polymerization starting at the terminal hydroxyl groups of the siloxane initiator. The siloxane may be a poly(dimethylsiloxane) glycol, wherein the hydroxyl groups are not directly attached to the silicon atom (e.g., a bis(hydroxyalkyl)-terminated poly(dimethylsiloxane)). The hydroxyalkyl groups of the bis(hydroxyalkyl)-terminated poly(dimethylsiloxane) may include a group derived from a 1,2-epoxide (such as ethylene oxide, 1,2-propylene oxide, 1,2-epoxycyclohexane or 1,2-butylene oxide) by the opening of an oxirane ring.

[0016] The siloxane may have a weight average molecular weight of 500 to 7,500 g / mol (eg, 600 to 7,000 g / mol, 750 to 5,000 g / mol, 800 to 1250 g / mol, or 900 to 1100 g / mol, etc.).

[0017] For bis(hydroxyalkyl)-terminated poly(dimethylsiloxane) initiators, the alkyl group may be C1-C 14 (For example, C1-C 10 , C1-C8, etc.) alkyl, which may be optionally inserted with -O-, N- or -S-. For example, the siloxane initiator may have formula (I) as shown below:

[0018]

[0019] wherein n can be an integer from 0 to 100, for example from 0, 1, 2, 3, 5, 8, 9 and up to 90, 70, 50, 40, 35, 30, 25, 20, 15 or 11.

[0020] In an exemplary embodiment, the siloxane-caprolactone block copolymer polyol is a reaction product of a bis(hydroxyalkyl)-terminated poly(dimethylsiloxane) as an initiator and caprolactone via ring-opening polymerization addition. The resulting siloxane-caprolactone block copolymer polyol can have a weight average molecular weight of 500 g / mol to 8000 g / mol (e.g., 1000 g / mol to 4000 g / mol, 1500 g / mol to 3000 g / mol, 1800 g / mol to 2200 g / mol, 2000 g / mol to 2150 g / mol, etc.). In an exemplary embodiment, the bis(hydroxyalkyl)-terminated poly(dimethylsiloxane) has formula (I) as described above.

[0021] In an exemplary embodiment, the siloxane-caprolactone block copolymer polyol can be an ABA type triblock caprolactone-siloxane-caprolactone block copolymer, wherein A represents a caprolactone unit and B represents a siloxane unit. In some embodiments, based on the weight of the siloxane-caprolactone block copolymer polyol and the block copolymer polyol, the siloxane-caprolactone block copolymer polyol has a siloxane segment content greater than 4.2% by weight and less than 92% by weight (e.g., 5% to 90% by weight, 8% to 80% by weight, 15% to 70% by weight, etc.). Based on the total weight of the polyurethane composition, the entire polyurethane composition can have a siloxane content of 3.0% to 15.0% by weight (e.g., 3.0% to 14% by weight).

[0022] The block copolymer can contain any relative amounts of siloxane blocks and caprolactone blocks. For example, based on the total weight of the siloxane-caprolactone block copolymer polyol, the copolymer can contain 5 to 95 wt % (e.g., 30 to 70 wt %, 40 to 60 wt %, etc.) of siloxane blocks and 5 to 95 wt % (e.g., 30 to 70 wt %, 40 to 60 wt %, etc.) of caprolactone blocks.

[0023] The second isocyanate-terminated prepolymer is derived from a polyester polyol, so that it is a reaction product of a polyisocyanate and a polyester polyol. The polyester polyol can have a high molar cohesive energy of>17.2 kJ / mol (e.g., ≥19.9 kJ / mol, 25 kJ / mol to 45 kJ / mol, 30 kJ / mol to 40 kJ / mol, 35 kJ / mol to 40 kJ / mol, etc.). The polyester polyol can have a nominal hydroxyl functionality of 2 to 5 (e.g., can be a diol or triol). The polyester polyol can have a weight average molecular weight of at least 500 g / mol, at least 800 g / mol, at least 1000 g / mol, at least 1500 g / mol, at least 1800 g / mol and / or less than 3500 g / mol.

[0024] Polyester polyol can be polycaprolactone polyol, makes it derive from the polymerization of caprolactone monomer.Polycaprolactone polyol can be diol.Polycaprolactone polyol can have the weight average molecular weight of 500g / mol to 3500g / mol (for example, 500g / mol to 3000g / mol, 1000g / mol to 2500g / mol, 1500g / mol to 2500g / mol, 1900g / mol to 2100g / mol etc.).

[0025] Isocyanate Reactive Components

[0026] The isocyanate reactive component comprises at least one chain extender and may optionally comprise other additives. Exemplary chain extenders include alcohols and / or amines having a low weight average molecular weight of less than 1000 g / mol, less than 750 g / mol, less than 500 g / mol, less than 250 g / mol, and / or greater than 50 g / mol. The chain extender may be a diol, a triol, or a diamine. Exemplary chain extenders include butanediol.

[0027] The chain extender can comprise 50 to 100 wt % (e.g., 60 to 100 wt %, 70 to 100 wt %, 80 to 100 wt %, 90 to 99.9 wt %, 95 to 99.9 wt %, etc.) of the total weight of the isocyanate-reactive components.

[0028] The isocyanate reactive component may include one or more additives, such as catalysts, plasticizers, flame retardants, pigments, tackifiers, rheology modifiers, polymerization inhibitors, fillers, or any combination thereof. For example, the isocyanate reactive component may include one or more catalysts to adjust the reaction kinetics, and the amount thereof may be 0 wt % to 3 wt % based on the total weight of the isocyanate reactive component.

[0029] The isocyanate reactive component can be solvent-free. As used herein, the term "solvent-free" means that the composition can be applied without an organic solvent or an aqueous carrier (e.g., up to 100 percent solids). In some embodiments of the present disclosure, the composition comprises less than 4 wt%, less than 1 wt%, less than 0.1 wt%, less than 100 ppm (by weight), less than 10 ppm (by weight), and / or less than 1 ppm (by weight) of any organic or inorganic solvent or water, or does not contain any organic or inorganic solvent or water.

[0030] The polyurethane composition may be substantially free of any polyether polyols (such as PPG), for example, based on the total weight of the polyurethane composition, comprising less than 1 wt%, less than 0.1 wt%, less than 100 ppm (by weight), less than 10 ppm (by weight), etc., of any polyether polyol, or free of any polyether polyol. The polyurethane composition may be substantially free of any nanofillers (such as melanin, cellulose, or graphene oxide), for example, based on the total weight of the polyurethane composition, comprising less than 1 wt%, less than 0.1 wt%, less than 100 ppm (by weight), less than 10 ppm (by weight), etc., of any nanofillers, or free of any nanofillers.

[0031] Application of polyurethane compositions

[0032] In other aspects, the present disclosure provides an artificial leather prepared using a polyurethane composition. For example, a prepolymer blend can be mixed with an isocyanate reactive component using a high pressure mixing head, and then poured and cast / cured on a base fabric (such as a textile) to form an artificial leather product. Release paper with certain decorative patterns can be applied to an uncured polyurethane resin, and then peeled off after the polyurethane composition is fully cured and the artificial leather is formed.

[0033] In some embodiments, the polyurethane composition can be cured at room temperature (about 25° C.). In some embodiments, the curable mixture can be subjected to pressure or heat (eg, at a temperature of 30° C. to 120° C. and / or 30° C. to 90° C.).

[0034] Example

[0035] Some embodiments will now be described in the following examples, in which all parts and percentages are by weight unless otherwise indicated. Unless otherwise indicated, all molecular weights are based on weight average.

[0036] raw materials

[0037] Table 1. Raw materials used in the examples

[0038]

[0039] Poly(ε-caprolactone)-b-poly(dimethylsiloxane)-b-poly(ε-caprolactone)(HO-PCL-PDMS-PCL-OH) synthesis :

[0040] HO-PCL-PDMS-PCL-OH (with Mw=2080 g / mol, PDI=1.51; weight ratio between PDMS / PCL=1:1) was synthesized via ring-opening polymerization of ε-caprolactone using HO-PDMS-OH as a macroinitiator. 100 g of macroinitiator, 100 g of ε-caprolactone and n-butyl titanate (TBT, 25 ppm) were fed into a 500 ml glass reactor equipped with a vacuum pump and an oil bath at room temperature under a nitrogen atmosphere. The system was reacted at 120° C. for 17 hours under stirring, and then vacuum was applied at 150 mbar and 135° C. for 3 hours. The final product was cooled to 80° C., then filtered, packaged and sampled for determination.

[0041] Poly(ε-caprolactone)-b-poly(dimethylsiloxane)-b-poly(ε-caprolactone) polyurethane prepolymer (Pre PCL-PDMS-PCL ) :

[0042] 27.67 g of MDI and 0.01 g of benzoyl chloride were fed into a 500 mL three-necked round-bottom flask and mixed at 55° C. and nitrogen atmosphere. After that, 72.32 g of HO-PCL-PDMS-PCL-OH was charged into the flask and incubated at 85° C. for 2 hours to obtain a prepolymer. The prepolymer was then cooled to 60° C. for packaging, sampling, and characterization.

[0043] Poly (ε-caprolactone) polyurethane prepolymer (Pre PCL ) :

[0044] 27.67 g of MDI and 0.01 g of benzoyl chloride were fed into a 500 mL three-necked round-bottom flask and mixed at 55° C. under a nitrogen atmosphere. After that, 72.32 g of poly(ε-caprolactone) diol was charged into the flask and incubated at 85° C. for 2 hours to obtain a prepolymer. The prepolymer was then cooled to 60° C. for packaging, sampling, and characterization.

[0045] Poly (dimethylsiloxane) polyurethane prepolymer PDMS ) :

[0046] 27.67 g of MDI and 0.01 g of benzoyl chloride were charged into a 500 mL three-necked round-bottom flask and mixed at 55° C. under a nitrogen atmosphere. After that, 72.32 g of poly(dimethylsiloxane)diol (2000 g / mol) was charged into the flask and incubated at 85° C. for 2 hours to obtain a prepolymer. The prepolymer was then cooled to 60° C. for packaging, sampling, and characterization.

[0047] Polypropylene glycol polyurethane prepolymer PPG ) :

[0048] 27.67 g of MDI and 0.01 g of benzoyl chloride were charged into a 500 mL three-necked round-bottom flask and mixed at 55° C. under a nitrogen atmosphere. TM2000 LM was charged into a flask and incubated at 85°C for 2 hours to obtain a prepolymer. The prepolymer was then cooled to 60°C for packaging, sampling and characterization.

[0049] Synthesis of Comparative Example A (CE.A) :

[0050] CE.A was prepared by the following manual mixing procedure. (a) The prepolymer Pre PCL Preheat at 80°C for at least 30 minutes to ensure a low viscosity liquid before use. (b) Preheat the aluminum mold with release agent at 110°C for at least 30 minutes before use. (c) Mix 40g of Pre PCL (d) The mixture was poured into a preheated mold and the system was kept at 110°C for 1 hour, followed by cooling to below 60°C. (e) The polyurethane sample was carefully demolded to avoid damaging the sample with gloves, and then post-cured at 110°C for at least 16 hours.

[0051] Synthesis of Comparative Example B (CE.B) :

[0052] CE.B was prepared via the following manual mixing procedure. (a) 2 g of prepolymer Pre PCL-PDMS-PCL and 38g prepolymer Pre PCL Mix for 1 minute to efficiently mix the prepolymer. (b) Preheat the prepolymer mixture at 80°C for at least 30 minutes to ensure that a low viscosity liquid is obtained before use. (c) Preheat the aluminum mold with a release agent at 110°C for at least 30 minutes before use. (d) Blend 40g of the prepolymer mixture and 2.61g of BDO containing catalyst 1 (stored at room temperature) with a Flacktec high-speed mixer at 2500rpm for 1 minute to efficiently mix the components and remove any bubbles or dissolved gases. (e) Pour the mixture into the preheated mold and keep the system at 110°C for 1 hour, then cool to below 60°C. (f) Demold the polyurethane sample carefully to avoid damaging the sample with gloves, and then post-cure the polyurethane sample at 110°C for at least 16 hours.

[0053] Synthesis of Comparative Example (CE.C) :

[0054] CE.C was prepared via the following manual mixing procedure. (a) 24 g of prepolymer Pre PCL-PDMS-PCL and 16g prepolymer Pre PCLMix for 1 minute to efficiently mix the prepolymer. (b) Preheat the prepolymer mixture at 80°C for at least 30 minutes to ensure that a low viscosity liquid is obtained before use. (c) Preheat the aluminum mold with a release agent at 110°C for at least 30 minutes before use. (d) Blend 40g of the prepolymer mixture and 2.61g of BDO containing catalyst 1 (stored at room temperature) with a Flacktec high-speed mixer at 2500rpm for 1 minute to efficiently mix the components and remove any bubbles or dissolved gases. (e) Pour the mixture into the preheated mold and keep the system at 110°C for 1 hour, then cool to below 60°C. (f) Demold the polyurethane sample carefully to avoid damaging the sample with gloves, and then post-cure the polyurethane sample at 110°C for at least 16 hours.

[0055] Synthesis of Comparative Example D (CE.D) :

[0056] CE.D was prepared by the following manual mixing procedure. (a) The prepolymer Pre PCL-PDMS-PCL Preheat at 80°C for at least 30 minutes to ensure a low viscosity liquid before use. (b) Preheat the aluminum mold with release agent at 110°C for at least 30 minutes before use. (c) Mix 40 g of prepolymer Pre with a Flacktec high speed mixer at 2500 rpm. PCL-PDMS-PCL (d) The mixture was poured into a preheated mold and the system was kept at 110°C for 1 hour, followed by cooling to below 60°C. (e) The polyurethane sample was carefully demolded to avoid damaging the sample with gloves, and then post-cured at 110°C for at least 16 hours.

[0057] Synthesis of Comparative Example E (CE.E) :

[0058] CE.E was prepared by the following manual mixing procedure. (a) The prepolymer Pre PDMS Preheat at 80°C for at least 30 minutes to ensure a low viscosity liquid before use. (b) Preheat the aluminum mold with release agent at 110°C for at least 30 minutes before use. (c) Mix 40 g of prepolymer Pre with a Flacktec high speed mixer at 2500 rpm. PDMS (d) The mixture was poured into a preheated mold and the system was kept at 110°C for 1 hour, followed by cooling to below 60°C. (e) The polyurethane sample was carefully demolded to avoid damaging the sample with gloves, and then post-cured at 110°C for at least 16 hours.

[0059] Synthesis of Comparative Example F (CE.F) :

[0060] CE.F was prepared via the following manual mixing procedure. (a) 20 g of prepolymer Pre PDMS and 20g prepolymer Pre PCL Mix for 1 minute to efficiently mix the prepolymer. (b) Preheat the prepolymer mixture at 80°C for at least 30 minutes to ensure that a low viscosity liquid is obtained before use. (c) Preheat the aluminum mold with a release agent at 110°C for at least 30 minutes before use. (d) Blend 40g of the prepolymer mixture and 2.61g of BDO containing catalyst 1 (stored at room temperature) with a Flacktec high-speed mixer at 2500rpm for 1 minute to efficiently mix the components and remove any bubbles or dissolved gases. (e) Pour the mixture into the preheated mold and keep the system at 110°C for 1 hour, then cool to below 60°C. (f) Demold the polyurethane sample carefully to avoid damaging the sample with gloves, and then post-cure the polyurethane sample at 110°C for at least 16 hours.

[0061] Synthesis of Comparative Example G (CE.G) :

[0062] CE.G was prepared by the following manual mixing procedure. (a) 16 g of prepolymer Pre PCL-PDMS-PCL and 24g prepolymer Pre PPG Mix for 1 minute to efficiently mix the prepolymer. (b) Preheat the prepolymer mixture at 80°C for at least 30 minutes to ensure that a low viscosity liquid is obtained before use. (c) Preheat the aluminum mold with a release agent at 110°C for at least 30 minutes before use. (d) Blend 40g of the prepolymer mixture and 2.61g of BDO containing catalyst 1 (stored at room temperature) with a Flacktec high-speed mixer at 2500rpm for 1 minute to efficiently mix the components and remove any bubbles or dissolved gases. (e) Pour the mixture into the preheated mold and keep the system at 110°C for 1 hour, then cool to below 60°C. (f) Demold the polyurethane sample carefully to avoid damaging the sample with gloves, and then post-cure the polyurethane sample at 110°C for at least 16 hours.

[0063] Synthesis of Working Example 1 (WE.1) :

[0064] WE.1 was prepared by the following manual mixing procedure. (a) 4 g of prepolymer Pre PCL-PDMS-PCL and 36g prepolymer Pre PCLMix for 1 minute to efficiently mix the prepolymer. (b) Preheat the prepolymer mixture at 80°C for at least 30 minutes to ensure that a low viscosity liquid is obtained before use. (c) Preheat the aluminum mold with a release agent at 110°C for at least 30 minutes before use. (d) Blend 40g of the prepolymer mixture and 2.61g of BDO containing catalyst 1 (stored at room temperature) with a Flacktec high-speed mixer at 2500rpm for 1 minute to efficiently mix the components and remove any bubbles or dissolved gases. (e) Pour the mixture into the preheated mold and keep the system at 110°C for 1 hour, then cool to below 60°C. (f) Demold the polyurethane sample carefully to avoid damaging the sample with gloves, and then post-cure the polyurethane sample at 110°C for at least 16 hours.

[0065] Synthesis of Working Example 2 (WE.2) :

[0066] WE.2 was prepared by the following manual mixing procedure. (a) 8 g of prepolymer Pre PCL-PDMS-PCL and 32g prepolymer Pre PCL Mix for 1 minute to efficiently mix the prepolymer. (b) Preheat the prepolymer mixture at 80°C for at least 30 minutes to ensure that a low viscosity liquid is obtained before use. (c) Preheat the aluminum mold with a release agent at 110°C for at least 30 minutes before use. (d) Blend 40g of the prepolymer mixture and 2.61g of BDO containing catalyst 1 (stored at room temperature) with a Flacktec high-speed mixer at 2500rpm for 1 minute to efficiently mix the components and remove any bubbles or dissolved gases. (e) Pour the mixture into the preheated mold and keep the system at 110°C for 1 hour, then cool to below 60°C. (f) Demold the polyurethane sample carefully to avoid damaging the sample with gloves, and then post-cure the polyurethane sample at 110°C for at least 16 hours.

[0067] Synthesis of Working Example 3 (WE.3) :

[0068] WE.3 was prepared by the following manual mixing procedure. (a) 16 g of prepolymer Pre PCL-PDMS-PCL and 24g prepolymer Pre PCLMix for 1 minute to efficiently mix the prepolymer. (b) Preheat the prepolymer mixture at 80°C for at least 30 minutes to ensure that a low viscosity liquid is obtained before use. (c) Preheat the aluminum mold with a release agent at 110°C for at least 30 minutes before use. (d) Blend 40g of the prepolymer mixture and 2.61g of BDO containing catalyst 1 (stored at room temperature) with a Flacktec high-speed mixer at 2500rpm for 1 minute to efficiently mix the components and remove any bubbles or dissolved gases. (e) Pour the mixture into the preheated mold and keep the system at 110°C for 1 hour, then cool to below 60°C. (f) Demold the polyurethane sample carefully to avoid damaging the sample with gloves, and then post-cure the polyurethane sample at 110°C for at least 16 hours.

[0069] The present disclosure describes two product formulations: an isocyanate prepolymer that exhibits storage stability, low viscosity, and high moisture resistance as summarized in Table 2, and a polyurethane composition that exhibits high mechanical strength, high elongation at break, and low thermal conductivity.

[0070] Table 2: Specifications and properties

[0071]

[0072] Note: *Siloxane weight % is calculated based on the total weight of polyurethane.

[0073] **Caprolactone weight % is based on the total weight of the polyurethane.

[0074] Reference Examples :

[0075] Working Example 1: Containing Pre PCL (90) / Pre PCL-PDMS-PCL (10) a prepolymer mixture, i.e., 90% by weight of Pre PCL and 10 wt% Pre PCL-PDMS-PCL The isocyanate prepolymer mixture is composed of a low viscosity, moisture resistance and storage stability. The corresponding polyurethane derived therefrom exhibits the desired properties of high strength, high elongation at break and low thermal conductivity.

[0076] Working Example 2: Containing Pre PCL (80) / Pre PCL-PDMS-PCL (20) a prepolymer mixture, i.e., 80% by weight of Pre PCL and 20 wt% Pre PCL-PDMS-PCL The isocyanate prepolymer mixture is composed of a low viscosity, moisture resistance and storage stability. The corresponding polyurethane derived therefrom exhibits the desired properties of high strength, high elongation at break and low thermal conductivity.

[0077] Working Example 3: Containing Pre PCL (60) / Pre PCL-PDMS-PCL (40) a prepolymer mixture, i.e., 60 wt. % of Pre PCL and 40 wt% Pre PCL-PDMS-PCL The isocyanate prepolymer mixture is composed of a low viscosity, moisture resistance and storage stability. The corresponding polyurethane derived therefrom exhibits the desired properties of high strength, high elongation at break and low thermal conductivity.

[0078] In contrast, the comparative examples are as follows:

[0079] Com-A: Contains Pre PCL , which exhibits high viscosity and moisture sensitivity and is derived from Pre PCL The corresponding polyurethanes show high strength, low elongation at break and high thermal conductivity.

[0080] Com-B: Contains 95% by weight of Pre PCL and 5 wt% Pre PCL-PDMS-PCL The present invention relates to a prepolymer mixture of polyurethane, which exhibits high viscosity, moisture sensitivity and storage stability, and the corresponding polyurethane derived therefrom exhibits low strength, high elongation at break and relatively high thermal conductivity.

[0081] Com-C: Contains 40% by weight of Pre PCL and 60 wt% Pre PCL-PDMS-PCL The present invention discloses a prepolymer mixture of polyurethane, which exhibits low viscosity, moisture resistance and storage stability, and the corresponding polyurethane derived therefrom exhibits low strength, low elongation at break and relatively low thermal conductivity.

[0082] Com-D: Contains Pre PCL-PDMS-PCL , i.e., an isocyanate prepolymer based on a triblock copolymer diol HO-PCL-PDMS-PCL-OH, which exhibits low viscosity, moisture resistance, and storage stability. The corresponding polyurethane derived therefrom exhibits relatively low strength, low elongation at break, and low thermal conductivity.

[0083] Com-E: Includes Pre PDMS , i.e., poly(dimethylsiloxane) and isocyanate prepolymers, which exhibit low viscosity and moisture resistance, and the corresponding polyurethanes derived therefrom exhibit relatively low strength, low elongation at break, and low thermal conductivity.

[0084] Com-F: Contains Pre PDMS / Pre PCL , that is, by equal amounts of Pre PDMS and Pre PCLThe isocyanate prepolymer mixture is composed of low viscosity, moisture resistance and storage instability. The corresponding polyurethane derived therefrom shows low strength, low elongation at break and low thermal conductivity.

[0085] Com-G: Includes Pre PPG (60) / Pre PCL-PDMS-PCL (40), i.e. 60 wt% of Pre PPG and 40 wt% Pre PCL-PDMS-PCL The mixture of PU and PU exhibits low viscosity, moisture resistance and storage stability. The corresponding polyurethane derived therefrom exhibits low strength, low elongation at break and relatively low thermal conductivity.

[0086] Experimental Procedure

[0087] The viscosity of the polyurethane prepolymer was tested by the following procedure: (Pa·s / 50°C).

[0088] During the test, take 1g of the prepolymer product, place it on the plate, close the plate, fill the prepolymer between the two plates, and eliminate the air bubbles. When the sample temperature is stable, start the rotor to test the rheological properties of variable shear rate.

[0089] Mechanical property tests were performed according to GB / T1447.

[0090] Samples of each polyurethane were prepared (1×2×12 mm, n=5) and stretched to failure at a rate of 10 mm / min using an Instron 5966 uniaxial tensile tester equipped with a 1 kN load cell. The elastic modulus, tensile strength and ultimate elongation at break were calculated from the resulting engineering stress / strain curves.

[0091] The thermal conductivity was measured according to ISO / DIS 22007-2.2 (Hotdisk method).

[0092] Thermal conductivity was evaluated by hotdisk transient technique using a Kapton 5465 sensor at 35 mW heating rate and 40 seconds duration per test.

[0093] Determination of skinning time of prepolymer :

[0094] Take 10g of each prepolymer and place it in a 50ml plastic beaker, and place the beaker in an oven at 45% humidity and 23°C. Start time recording. Take out the beaker regularly and gently touch the surface of the prepolymer with a plastic stick. As the reaction between the prepolymer and the moisture increases, the surface viscosity increases. When the surface of the prepolymer is no longer sticky, stop time recording. Record this duration as the skinning time of the prepolymer.

[0095] Calculation of Molar Cohesive Energy of Polymers

[0096] The cohesive energy of each chain is defined as the average energy of each chain required to separate all polymer chains in a condensed state into infinity. In order to calculate the cohesive energy, five polymer chains with corresponding molecular weights are used for calculation. The Forcite module of Materials Studio (Accelrys Inc., San Diego) with COMPASSII force field is then used for calculation, and the atomic point charge is calculated by the Gasteiger method. The initial configuration of the simulation system is constructed by randomly distributing the polymer chains in the simulation unit using the Amorphous Cell module of Materials Studio. The cohesive energy of each chain is calculated by the following equation:

[0097]

[0098] in is the average potential energy of the isolated polymer chains in vacuum, is the average potential energy of a condensed system consisting of five polymer chains. The potential energy of the isolated polymer chains was calculated by averaging 20 frames over 100 picoseconds after a 1 nanosecond equilibrium simulation. For the condensed system, the potential energy was calculated by the same method after an annealing simulation.

Claims

1. A polyurethane composition, comprising: Based on the total weight of the polyurethane composition, 50 wt % to 98 wt % of an isocyanate component, the isocyanate component comprising: 7 to 55 weight percent, based on the total weight of the isocyanate component, of a first isocyanate-terminated prepolymer derived from a siloxane-caprolactone block copolymer polyol, and 45 to 93 weight percent, based on the total weight of the isocyanate component, of a second isocyanate-terminated prepolymer derived from a polyester polyol; and 2 wt % to 50 wt % of an isocyanate reactive component, based on the total weight of the polyurethane composition, the isocyanate reactive component comprising a chain extender.

2. The polyurethane composition of claim 1, wherein the polyester polyol is a polycaprolactone polyol. 3 . The polyurethane composition according to claim 2 , wherein the polycaprolactone polyol is a diol and has a weight average molecular weight of 500 to 3000 g / mol.

4. The polyurethane composition according to any one of claims 1 to 3, wherein the siloxane-caprolactone block copolymer polyol is a reaction product of a bis(hydroxyalkyl)-terminated poly(dimethylsiloxane) as an initiator and caprolactone via ring-opening polymerization addition, and the siloxane-caprolactone block copolymer polyol has a weight average molecular weight of 1000 g / mol to 4000 g / mol.

5. The polyurethane composition of claim 4, wherein the bis(hydroxyalkyl)-terminated poly(dimethylsiloxane) has formula (I): Wherein n can be an integer from 0 to 100.

6. The polyurethane composition according to any one of claims 1 to 5, wherein the polyurethane composition has a siloxane content of 3.0% to 15.0% by weight.

7. The polyurethane composition of any one of claims 1 to 6, wherein the isocyanate component consists essentially of 10 to 40 weight percent of the first isocyanate-terminated prepolymer and 60 to 90 weight percent of the second isocyanate-terminated prepolymer.

8. The polyurethane composition according to any one of claims 1 to 7, wherein the polyurethane composition is substantially free of polyether polyols and nanofillers.

9. The polyurethane composition according to any one of claims 1 to 8, wherein the polyurethane composition is mixed and poured on a base fabric layer to form an artificial leather product.

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