High flow, easy processable thermoplastic polyurethane elastomers and their use

Abstract

The application relates to a high-flow easy-to-process thermoplastic polyurethane elastomer and application thereof, which comprises a reaction product of a polyisocyanate, a polymer polyol, a chain extender and an end-capping agent; wherein the number-average molecular weight of the polymer polyol is above 2200 g / mol, and the end-capping agent comprises a monohydric alcohol with more than 10 carbon atoms; the high-flow easy-to-process thermoplastic polyurethane elastomer is applied to a rubber-coated modified material containing the thermoplastic polyurethane elastomer; the modified material is obtained by mixing and processing the thermoplastic polyurethane elastomer and other polymer materials, and the processing mode comprises an injection molding processing technology; the rubber-coated modified material can be used for coating other materials and is used as a protective sleeve, a protective shell and other products of some 3C products. The thermoplastic polyurethane elastomer has a relatively fast forming speed and good mechanical properties, and the flowability of the thermoplastic polyurethane elastomer at low temperature is remarkably improved, which is beneficial to downstream processing.

Description

Technical Field

[0001] This invention relates to a thermoplastic polyurethane elastomer, specifically to a high-flow, easily processable thermoplastic polyurethane elastomer and its applications. Background Technology

[0002] Thermoplastic polyurethane elastomer (TPU) overmolding modification is an important processing technology in the current plastics processing field. It refers to using TPU material to coat other materials. Due to its good flexibility and elasticity, TPU-modified overmolding materials can improve the overall durability and aesthetics of products, effectively prevent scratches, and protect relatively expensive equipment, thus having great application prospects.

[0003] Overmolding modified materials are typically obtained by blending TPU with nonpolar polymers such as styrene(S)-hydrogenated butadiene(EB)-styrene(S) block copolymer (SEBS) or styrene(S)-butadiene(B)-styrene(S) block copolymer (SBS). However, due to the strong hydrogen bonding in TPU, its processing temperature is usually significantly higher than that of SEBS and SBS. Furthermore, the particle flowability of TPU mixed with SEBS or SBS is significantly slower at lower processing temperatures, making the processing of certain complex shapes difficult. Therefore, there is an urgent market demand for a TPU material with good flowability and easy processing for use in the overmolding modification field. Summary of the Invention

[0004] Technical Problem: The purpose of this invention is to provide a high-flow, easily processable thermoplastic polyurethane elastomer and its applications, utilizing this thermoplastic polyurethane elastomer for modified processing in the field of overmolding materials. This ensures a fast molding speed and good mechanical properties for the thermoplastic polyurethane elastomer, while significantly improving its flowability at low temperatures, which is beneficial for downstream processing.

[0005] Technical solution: The present invention provides a high-flow, easily processable thermoplastic polyurethane elastomer, comprising a reactant obtained by reacting a polyisocyanate, a polymeric polyol, a chain extender, and a capping agent; wherein the number average molecular weight of the polymeric polyol is above 2200 g / mol, and the capping agent comprises a monohydric alcohol with more than 10 carbon atoms.

[0006] The high-flow, easily processable thermoplastic polyurethane elastomer further contains antioxidants, which include one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tri(nonylphenyl) phosphite, and triisodecyl phosphite.

[0007] The polymer polyol includes polyester polyol and does not contain polyether polyol; the polyester polyol includes one or more of the following: polyester polyol obtained by polycondensation reaction of at least two diols and at least one diacid; the average hydroxyl functionality of the polyester polyol is 2; the number average molecular weight of the polymer polyol is 2500-4000 g / mol, more preferably 2500-3500 g / mol.

[0008] The diol comprises diol A and diol B, wherein diol A has 4 to 8 carbon atoms, diol B has 2 to 3 carbon atoms, and the molar ratio of diol A to diol B is 1:1 to 1:2; wherein diol A comprises one or more of butanediol, pentanediol, neopentanediol, hexanediol, heptaethylenediol, and octanediol, preferably, diol A comprises butanediol and / or hexanediol; wherein diol B comprises one or a combination of ethylene glycol and propylene glycol; and wherein the diacid comprises one or more of succinic acid, glutaric acid, and adipic acid.

[0009] The chain extender comprises a small molecule diol, including one or more of ethylene glycol, propylene glycol, butanediol, pentanediol, and hexanediol; the end-capping agent comprises a straight-chain aliphatic monohydric alcohol with 10 to 20 carbon atoms; wherein the straight-chain aliphatic monohydric alcohol comprises at least one of 1-nonanol, n-dodecyl alcohol, 1-tetaneol, n-tetradecyl alcohol, 1-hexadecyl alcohol, 1-octadecyl alcohol, and 1-eicosyl alcohol, preferably at least one of n-tetradecyl alcohol, 1-hexadecyl alcohol, 1-octadecyl alcohol, and 1-eicosyl alcohol.

[0010] The polyisocyanates include one or more of diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI), terephthalic diisocyanate (PPDI), and / or derivatives and / or modified polymers.

[0011] The polyisocyanate derivatives include polyisocyanate dimers and / or polyisocyanate trimers; the polyisocyanate modified polymers include carbodiimide-modified isocyanate polymers.

[0012] The isocyanate index is 0.95:1 to 1.05:1; the isocyanate index is the molar ratio of NCO groups in the polyisocyanate to NCO-reactive groups in the polymer polyol, chain extender and end capping agent.

[0013] By weight, high-flow, easily processable thermoplastic polyurethane elastomers include:

[0014]

[0015] Preferably, the end-capping agent accounts for no more than 0.5% of the total mass of the polyisocyanate, polymer polyol, chain extender, and end-capping agent.

[0016] The high-flow, easily processed thermoplastic polyurethane elastomer has a Shore hardness of 80–90 A.

[0017] The high-flow, easily processable thermoplastic polyurethane elastomer of the present invention is applied to a modified material containing the aforementioned thermoplastic polyurethane elastomer for overmolding. The modified material is obtained by mixing the aforementioned modified material with other polymer materials, including injection molding. The overmolded modified material can be used to coat other materials, serving as protective cases, shells, and other products for some 3C products.

[0018] Beneficial effects: The present invention designs the structure of polymer polyols, using polymer polyols with a number average molecular weight of more than 2200 g / mol as the reaction component of thermoplastic polyurethane elastomers, and introduces a small amount of long carbon chain end-capping agent. The thermoplastic polyurethane elastomer is modified and processed for use in the field of overmolding materials. This not only ensures the fast molding speed and good mechanical properties of thermoplastic polyurethane elastomers, but also significantly improves their fluidity at low temperatures, which is beneficial to downstream processing. Detailed Implementation

[0019] The high-flow, easily processable thermoplastic polyurethane elastomer comprises a reaction product obtained from polyisocyanate, polymeric polyol, chain extender, and end-capping agent, wherein the number-average molecular weight of the polymeric polyol is above 2200 g / mol, and the end-capping agent comprises a monohydric alcohol with more than 10 carbon atoms.

[0020] Furthermore, the number average molecular weight of the polymer polyol is between 2500 and 4000 g / mol, more preferably between 2500 and 3500 g / mol;

[0021] The polymer polyols mentioned include polyester polyols but do not contain polyether polyols;

[0022] The polyester polyols include one or more of the following: polyester polyols obtained by polycondensation reaction of at least two diols and at least one diacid;

[0023] Furthermore, the diol includes diol A and diol B, wherein diol A has 4 to 8 carbon atoms and diol B has 2 to 3 carbon atoms.

[0024] The molar ratio of diol A to diol B is 1:1 to 1:2;

[0025] Furthermore, the diol A includes one or more of butanediol (BDO), pentanediol (PD), neopentanediol (NPG), hexanediol (HG), heptahydrate (HDO), and octanediol (ODO), preferably, the diol A includes butanediol and / or hexanediol.

[0026] Furthermore, the diol B includes one or a combination of ethylene glycol (EG) and propylene glycol (PG);

[0027] Furthermore, the dicarboxylic acid includes one or more of succinic acid, glutaric acid, and adipic acid;

[0028] In some embodiments of the present invention, the dicarboxylic acid includes adipic acid (AA);

[0029] The average hydroxyl functionality of the polyester polyol is 2.

[0030] In some embodiments of the present invention, the polyester polyol includes at least one of polybutylene adipate polyol (PBEA) and polyhexylene adipate polyol (PHEA).

[0031] Furthermore, the capping agent accounts for no more than 0.5% of the total mass of the polyisocyanate, polymer polyol, chain extender, and capping agent.

[0032] The chain extender includes small molecule diols, including one or more of ethylene glycol, propylene glycol, butanediol, pentanediol, and hexanediol.

[0033] Furthermore, the capping agent comprises a straight-chain aliphatic monohydric alcohol with 10 to 20 carbon atoms, including at least one of 1-nonanol, n-dodecyl alcohol, 1-tetaneol, n-tetradecyl alcohol, 1-hexadecyl alcohol, 1-octadecyl alcohol, and 1-eicosyl alcohol, preferably at least one of n-tetradecyl alcohol, 1-hexadecyl alcohol, 1-octadecyl alcohol, and 1-eicosyl alcohol.

[0034] The polyisocyanates include one or more of diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI), terephthalic diisocyanate (PPDI), and / or derivatives and / or modified polymers.

[0035] In this invention, the polyisocyanate derivatives include polyisocyanate dimers and / or polyisocyanate trimers;

[0036] In this invention, the polyisocyanate modified polymers include carbodiimide modified isocyanate polymers.

[0037] Furthermore, the aforementioned high-flow, easily processable thermoplastic polyurethane elastomer is obtained by reacting the following raw materials in parts by weight:

[0038]

[0039] Furthermore, the Shore hardness of the high-flow, easily processable thermoplastic polyurethane elastomer is 80-90A;

[0040] Furthermore, the isocyanate index of the high-flow, easily processable thermoplastic polyurethane elastomer is 0.95:1 to 1.05:1;

[0041] The isocyanate index is the molar ratio of NCO groups in the polyisocyanate to NCO-reactive groups in the polymer polyol, chain extender, and capping agent.

[0042] The high-flow, easily processed thermoplastic polyurethane elastomer further contains antioxidants, which include one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tri(nonylphenyl) phosphite, and triisodecyl phosphite.

[0043] The amount of antioxidant added is 0.05 to 1 wt%, calculated based on the total mass of the high-flow, easily processed thermoplastic polyurethane elastomer.

[0044] The present invention also provides a thermoplastic polyurethane elastomer overmolding modified material, which is obtained by mixing the modified material with thermoplastic polyurethane elastomer and other polymer materials. The processing method includes injection molding. The overmolding modified material can be used to coat other materials as protective cases, shells and other products for some 3C products.

[0045] The high-flow, easily processable thermoplastic polyurethane elastomer is prepared by mixing and reacting polyisocyanate, polymer polyol, chain extender, and end-capping agent.

[0046] The reaction equipment is not particularly limited, as long as it can ensure that the raw materials of each component can be fully mixed or reacted. For example, it can be selected from one or more of the following: screw extruder, internal mixer, stirred tank, and casting machine.

[0047] Furthermore, the high-flow, easily processable thermoplastic polyurethane elastomer is prepared in the presence of a protective gas that does not participate in the reaction, such as nitrogen or helium.

[0048] Furthermore, catalysts commonly used in the art can be added during the mixed reaction process to accelerate the reaction rate; including one or more of organotin catalysts, organotitanium catalysts, and organobismuth catalysts.

[0049] In some embodiments of the present invention, the high-flow, easily processable thermoplastic polyurethane elastomer is prepared using a twin-screw extruder, the steps of which include:

[0050] The insulation temperature for polyisocyanates is 40-80℃, for polymer polyols it is 90-130℃, for chain extenders it is 40-80℃, and for end-capping agents it is 90-120℃, to ensure that the raw materials are in a liquid state.

[0051] The above-mentioned heat-insulated polyisocyanate, polymer polyol, chain extender and end capping agent are added to the front section of a twin-screw extruder through a mixing system for mixing and reaction. The screw temperature is controlled at 140-180℃. The resulting polymer melt is obtained by underwater pelletizing and drying.

[0052] Preferably, other additives are selectively added to the rear section of the twin-screw extruder to mix with the molten thermoplastic polyurethane elastomer. Alternatively, the prepared thermoplastic polyurethane elastomer particles can be melted and mixed with other additives in a mixer.

[0053] Preferably, other additives in the art may be further added to the high-flow, easily processed thermoplastic polyurethane elastomer as needed to improve the performance of the thermoplastic polyurethane elastomer;

[0054] For example, lubricants, plasticizers, antioxidants, light stabilizers, etc.;

[0055] The lubricant is one or more of the following: oleamide, ethylene bisoleamide, EBS, HEEBS, montan ester wax, hydrogenated castor oil, or reactive silicone oil;

[0056] The plasticizers mentioned include one or more of acetylacetic acid tributyl citrate, dioctyl adipate, diethylene glycol dibenzoate, and dipropylene glycol dibenzoate;

[0057] The antioxidants mentioned include one or more of antioxidant 168, antioxidant 1010, antioxidant 1024, antioxidant 264, and antioxidant 445;

[0058] The light stabilizer includes one or more of light stabilizer 292, light stabilizer 944, light stabilizer 622, light stabilizer 770, light stabilizer 765, and light stabilizer 783.

[0059] The principles and features of the present invention are described below with reference to examples. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0060] Example 1

[0061]

[0062] Example 2

[0063]

[0064] Example 3

[0065]

[0066] Example 4

[0067]

[0068] Example 5

[0069]

[0070]

[0071] Example 6

[0072]

[0073] Example 7

[0074]

[0075] Example 8

[0076]

[0077] Example 9

[0078]

[0079] Example 10

[0080]

[0081] Example 11

[0082]

[0083]

[0084] Comparative Example 1

[0085] The difference between Comparative Example 1 and Example 1 is that the capping agent 1-octadecyl alcohol is not added, while everything else remains the same.

[0086] Comparative Example 2

[0087] The difference between Comparative Example 1 and Example 1 is that an equal mass of n-heptanol was used to replace the original capping agent 1-octadecanol, while everything else remained the same.

[0088] Comparative Example 3

[0089] The difference between Comparative Example 1 and Example 8 is that the original polyester polyol PBEA-Mn2200 (EG:BDO=1:1) was replaced with an equal mass of PBEA-Mn2000 (EG:BDO=1:1), while all other aspects remained the same.

[0090] The specific embodiments and comparative examples of the present invention are all prepared using a fourteen-section twin-screw extruder. Isocyanate, polyester polyol, chain extender and end-capping agent in the weight parts of raw materials in each embodiment are fed into the first section of the twin-screw reactive extruder through the injection system. After reaction, the melt passes through the die and is pelletized underwater. After drying, thermoplastic polyurethane elastomer can be obtained.

[0091] The first section of the twin-screw extruder contains 0.05% catalyst (dibutyltin dilaurate); the tenth section contains 0.1% lubricant (E wax and EBS in a 1:1 mass ratio) and 0.1% antioxidant (antioxidant 1010).

[0092] The products obtained in the above embodiments and comparative examples were subjected to relevant performance tests, and the test methods are as follows:

[0093] Hardness: Tested according to HG / T 5500-2019;

[0094] Tensile strength: Tested according to HG / T 5500-2019;

[0095] Tear strength: Tested according to HG / T 5500-2019;

[0096] Melt flow rate: Tested according to HG / T 5500-2019;

[0097] Exudation performance: The thermoplastic polyurethane elastomer sample was placed at 70℃ for one week, and the exudation on the sample surface was observed.

[0098] Processing performance: Thermoplastic polyurethane elastomer granules were injection molded using a K90VT / MJ4711 injection molding machine at 200℃. The demolding time of the test piece was recorded (i.e., the test piece did not change shape when pressed by hand after demolding). The shorter the demolding time, the faster the molding speed and the better the processability.

[0099] The performance comparison between the embodiments and comparative examples is shown in Table 1 below:

[0100] Table 1:

[0101]

Claims

1. A high-flow, easily processable thermoplastic polyurethane elastomer, characterized in that... The reaction product is obtained by reacting polyisocyanate, polymer polyol, chain extender and end capping agent; wherein the number average molecular weight of the polymer polyol is above 2200 g / mol, and the end capping agent includes monohydric alcohol with more than 10 carbon atoms. The polymer polyol is a polyester polyol; the polyester polyol is one or more of the polyester polyols obtained by polycondensation reaction of diol and diacid. The diol is composed of diol A and diol B, wherein diol A has 4 to 8 carbon atoms and diol B has 2 to 3 carbon atoms. The molar ratio of diol A to diol B is 1:1 to 1:2; The dicarboxylic acid is selected from one or more of succinic acid, glutaric acid, and adipic acid; The terminator comprises a straight-chain aliphatic monohydric alcohol having 10 to 20 carbon atoms; By weight, high-flow, easily processable thermoplastic polyurethane elastomers include: 20-35 parts by weight of polyisocyanate; 50-70 parts by weight of polymeric polyol; 5-10 parts by weight of chain extender; 0.2~0.5 parts by weight of capping agent; The average hydroxyl functionality of the polyester polyol is 2.

2. The high-flow, easily processable thermoplastic polyurethane elastomer according to claim 1, characterized in that... The high-flow, easily processable thermoplastic polyurethane elastomer further contains antioxidants, which include one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tri(nonylphenyl) phosphite, and triisodecyl phosphite.

3. A high-flow, easily processable thermoplastic polyurethane elastomer according to claim 1 or 2, characterized in that; The number-average molecular weight of the polymer polyol is between 2500 and 4000 g / mol.

4. The high-flow, easily processable thermoplastic polyurethane elastomer according to claim 3, characterized in that; The number average molecular weight of the polymer polyol is 2500~3500 g / mol.

5. The high-flow, easily processable thermoplastic polyurethane elastomer according to claim 4, characterized in that... The diol A includes one or more of butanediol, pentanediol, neopentanediol, hexanediol, heptahydrate, and octanediol.

6. The high-flow, easily processable thermoplastic polyurethane elastomer according to claim 5, characterized in that... Diol A includes butanediol and / or hexanediol; diol B includes ethylene glycol, propylene glycol, or a combination thereof.

7. A high-flow, easily processable thermoplastic polyurethane elastomer according to claim 1 or 2, characterized in that... The chain extender comprises small molecule diols, including one or more of ethylene glycol, propylene glycol, butanediol, pentanediol, and hexanediol; wherein the straight-chain aliphatic monohydric alcohols include at least one of 1-nonanol, n-dodecyl alcohol, 1-tetanediol, n-tetradecyl alcohol, 1-hexadecyl alcohol, 1-octadecyl alcohol, and 1-eicosyl alcohol.

8. The high-flow, easily processable thermoplastic polyurethane elastomer according to claim 7, characterized in that... The straight-chain aliphatic monohydric alcohol is at least one of n-tetradecanoic acid, 1-hexadecanoic acid, 1-octadecanoic acid, and 1-eicosanoic acid.

9. A high-flow, easily processable thermoplastic polyurethane elastomer according to claim 1 or 2, characterized in that... The polyisocyanates include at least one of diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI), and terephthalic diisocyanate (PPDI).

10. A high-flow, easily processable thermoplastic polyurethane elastomer according to claim 9, characterized in that... The isocyanate index is 0.95:1 to 1.05:1; the isocyanate index is the molar ratio of NCO groups in the polyisocyanate to NCO-reactive groups in the polymer polyol, chain extender and end capping agent.

11. The high-flow, easily processable thermoplastic polyurethane elastomer according to claim 1, characterized in that... The capping agent accounts for no more than 0.5% of the total mass of the polyisocyanate, polymer polyol, chain extender, and capping agent.

12. An application of the high-flow, easily processable thermoplastic polyurethane elastomer as described in claim 1 or 2, characterized in that... It is applied to modified materials containing the aforementioned thermoplastic polyurethane elastomer overcoating.

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