High-fluidity easy-to-process thermoplastic polyurethane elastomer and application thereof

Abstract

The invention relates to a high-flowability and easy-to-process thermoplastic polyurethane elastomer and application thereof. The thermoplastic polyurethane elastomer comprises a reactant obtained by reacting polyisocyanate, polymer polyol, a chain extender and an end-capping reagent, wherein the number-average molecular weight of the polymer polyol is more than 2200g / mol, and the end-capping reagent comprises monohydric alcohol with the carbon atom number of more than 10; the high-flowability and easy-to-process thermoplastic polyurethane elastomer disclosed by the invention is applied to a rubber coating modified material containing the thermoplastic polyurethane elastomer; the modified material is obtained by mixing and processing a thermoplastic polyurethane elastomer and other polymer materials, the processing mode comprises an injection molding processing technology, and the rubber coating modified material can be used for coating other materials and can be used as protective sleeves, protective shells and other products of some 3C products. The high forming speed and the good mechanical property of the thermoplastic polyurethane elastomer are guaranteed, meanwhile, the fluidity of the thermoplastic polyurethane elastomer at the low temperature is remarkably improved, and downstream processing is facilitated.

Description

Technical Field

[0001] The invention relates to a thermoplastic polyurethane elastomer, in particular to a high-flow and easy-to-process thermoplastic polyurethane elastomer and application thereof. Background Art

[0002] Thermoplastic polyurethane elastomer (TPU) encapsulation modification is an important processing technology in the current plastic processing field. It refers to the use of TPU materials to cover other materials. Due to its good flexibility and elasticity, TPU modified encapsulation materials can improve the overall durability and aesthetics of the product, effectively prevent scratches, and protect more expensive equipment. Therefore, it has great application prospects.

[0003] Encapsulation modification materials are usually obtained by mixing TPU with non-polar 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 effect of TPU, the processing temperature is usually significantly higher than that of SEBS and SBS. The particles of TPU mixed with SEBS or SBS have significantly slower fluidity when processed at lower temperatures, which makes the processing of some complex shapes difficult. Therefore, the market urgently needs a TPU material with good fluidity and easy processing for application in the field of encapsulation modification. Summary of the invention

[0004] Technical problem: The purpose of the present invention is to provide a high-flow and easy-to-process thermoplastic polyurethane elastomer and its application, and to utilize the modified thermoplastic polyurethane elastomer for application in the field of encapsulation materials. The faster molding speed and better mechanical properties of the thermoplastic polyurethane elastomer are ensured, while its fluidity at low temperatures is significantly improved, which is beneficial to downstream processing.

[0005] Technical solution: The present invention provides a high-flow and easy-to-process thermoplastic polyurethane elastomer, including a reactant obtained by reacting a polyisocyanate, a polymer polyol, a chain extender and a capping agent; wherein the number average molecular weight of the polymer polyol is above 2200 g / mol, and the capping agent includes a monohydric alcohol having more than 10 carbon atoms.

[0006] The high-flow and easy-to-process thermoplastic polyurethane elastomer also contains an antioxidant, which includes one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol, tris(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 polyester polyols obtained by condensation reaction of at least two diols and at least one dibasic acid; the average hydroxyl functionality of the polyester polyol is 2; the number average molecular weight of the polymer polyol is 2500-4000 g / mol, and more preferably 2500-3500 g / mol.

[0008] The diols include diol A and diol B, wherein the carbon number of diol A is 4 to 8, the carbon number of diol B is 2 to 3, and the molar ratio of diol A to diol B is 1:1 to 1:2; wherein the diol A includes one or more of butanediol, pentanediol, neopentyl glycol, hexanediol, heptanediol, and octanediol, preferably, the diol A includes butanediol and / or hexanediol; the diol B includes one or a combination of ethylene glycol and propylene glycol; and the dibasic acid includes one or more of succinic acid, glutaric acid, and adipic acid.

[0009] The chain extender includes a small molecule diol, including one or more of ethylene glycol, propylene glycol, butanediol, pentanediol, and hexanediol; the end capping agent includes a straight-chain aliphatic monohydric alcohol having a carbon number of 10 to 20; wherein the straight-chain aliphatic monohydric alcohol includes at least one of 1-nonanol, n-dodecanol, 1-tridecanol, n-tetradecanol, 1-hexadecanol, 1-octadecanol, and 1-eicosanol, preferably at least one of n-tetradecanol, 1-hexadecanol, 1-octadecanol, and 1-eicosanol.

[0010] The polyisocyanate includes one or more of diphenylmethane diisocyanate MDI, toluene diisocyanate TDI, hexamethylene diisocyanate HDI, diisocyanate dicyclohexylmethane HMDI, isophorone diisocyanate IPDI, p-phenylene 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 the NCO group in the polyisocyanate to the group reactive to NCO in the polymer polyol, the chain extender and the end-capping agent.

[0013] By weight, the high flow and easy processing thermoplastic polyurethane elastomer includes:

[0014]

[0015] Preferably, the mass proportion of the end-capping agent in the total mass of the polyisocyanate, the polymer polyol, the chain extender and the end-capping agent does not exceed 0.5%.

[0016] The high-flow, easy-to-process thermoplastic polyurethane elastomer has a Shore hardness of 80 to 90A;

[0017] The high-flow and easy-to-process thermoplastic polyurethane elastomer of the present invention is applied to the thermoplastic polyurethane elastomer encapsulated modified material; the modified material is obtained by mixing the thermoplastic polyurethane elastomer and other polymer materials, and the processing method includes injection molding. The encapsulated modified material can be used to coat other materials to serve as protective covers, protective shells and other products for some 3C products.

[0018] Beneficial effects: The present invention designs the structure of the polymer polyol, adopts the polymer polyol with a number average molecular weight of more than 2200 g / mol as the reaction component of the thermoplastic polyurethane elastomer, and introduces a small amount of long carbon chain capping agent. The modified processing of the thermoplastic polyurethane elastomer is applied to the field of encapsulation materials, which not only ensures the faster molding speed and better mechanical properties of the thermoplastic polyurethane elastomer, but also significantly improves its fluidity at low temperatures, which is beneficial to downstream processing. DETAILED DESCRIPTION

[0019] The high-flow and easy-to-process thermoplastic polyurethane elastomer comprises reactants obtained from 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 comprises a monohydric alcohol having more than 10 carbon atoms.

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

[0021] The polymer polyol includes polyester polyol and does not contain polyether polyol;

[0022] The polyester polyol includes one or more of the polyester polyols obtained by polycondensation reaction of at least two diols and at least one dibasic acid;

[0023] Furthermore, the diol comprises diol A and diol B, wherein the diol A has 4 to 8 carbon atoms, and the 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] Further, the diol A includes one or more of butanediol (BDO), pentanediol (PD), neopentyl glycol (NPG), hexanediol (HG), heptanediol (HDO), and octanediol (ODO). Preferably, the diol A includes butanediol and / or hexanediol.

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

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

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

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

[0030] In some examples of the present invention, the polyester polyol includes at least one of polyethylene glycol butanediol adipate polyol (PBEA) and polyethylene glycol hexanediol adipate polyol (PHEA);

[0031] Furthermore, the mass proportion of the end-capping agent in the total mass of the polyisocyanate, the polymer polyol, the chain extender and the end-capping agent does not exceed 0.5%.

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

[0033] Furthermore, the end-capping agent includes a straight-chain aliphatic monohydric alcohol having 10 to 20 carbon atoms, including at least one of 1-nonanol, n-dodecanol, 1-tridecanol, n-tetradecanol, 1-hexadecanol, 1-octadecanol, and 1-eicosanol, preferably at least one of n-tetradecanol, 1-hexadecanol, 1-octadecanol, and 1-eicosanol.

[0034] The polyisocyanate includes one or more of diphenylmethane diisocyanate MDI, toluene diisocyanate TDI, hexamethylene diisocyanate HDI, diisocyanate dicyclohexylmethane HMDI, isophorone diisocyanate IPDI, p-phenylene diisocyanate PPDI and / or derivatives and / or modified polymers;

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

[0036] The polyisocyanate-modified polymer in the present invention includes a carbodiimide-modified isocyanate polymer.

[0037] Furthermore, the high-flow, easy-to-process 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, easy-to-process thermoplastic polyurethane elastomer is 80 to 90A;

[0040] Further, the isocyanate index of the high-flow, easy-to-process thermoplastic polyurethane elastomer is 0.95:1 to 1.05:1;

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

[0042] The high-flow, easy-to-process thermoplastic polyurethane elastomer also contains an antioxidant, and the antioxidant includes one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol, tris(nonylphenyl) phosphite, and triisodecyl phosphite;

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

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

[0045] The high-flow, easy-to-process thermoplastic polyurethane elastomer is prepared by a mixed reaction of polyisocyanate, polymer polyol, chain extender and end-capping agent;

[0046] The reaction equipment is not particularly limited, as long as the various raw materials can be fully mixed or reacted, for example, one or more selected from a screw extruder, an internal mixer, a stirring kettle, and a casting machine;

[0047] Furthermore, the high-flow, easy-to-process 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, a catalyst commonly used in the art may be added during the mixed reaction process to accelerate the reaction rate; this includes one or more of an organic tin catalyst, an organic titanium catalyst, and an organic bismuth catalyst.

[0049] In some embodiments of the present invention, the high-flow and easy-to-process thermoplastic polyurethane elastomer is prepared by a twin-screw extruder, and the steps include:

[0050] The insulation temperature of polyisocyanate is 40-80℃, the insulation temperature of polymer polyol is 90-130℃, the insulation temperature of chain extender is 40-80℃, and the insulation temperature of end-capping agent is 90-120℃, so as to ensure that the raw materials are in liquid state;

[0051] The insulated polyisocyanate, polymer polyol, chain extender and end-capping agent are added to the front-end twin-screw extruder through a mixing system for mixing and reaction, the screw temperature is controlled at 140-180° C., and the obtained polymer melt is pelletized underwater and dried;

[0052] Preferably, other additives are selectively added to the rear section of the twin-screw to mix with the molten thermoplastic polyurethane elastomer, or the prepared thermoplastic polyurethane elastomer particles and other additives are melt-mixed again in the mixer;

[0053] Preferably, according to the requirements, other additives in the art are further added to the high-flow, easy-to-process thermoplastic polyurethane elastomer to improve the performance of the thermoplastic polyurethane elastomer;

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

[0055] One or more of the lubricants oleamide, ethylene bisoleamide, EBS, HEEBS, montan ester wax, hydrogenated castor oil or reactive silicone oil;

[0056] The plasticizer includes one or more of tri-n-butyl acetyl citrate, dioctyl adipate, diethylene glycol dibenzoate, and dipropylene glycol dibenzoate;

[0057] The antioxidant includes 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 in conjunction with examples. The examples are only used to explain the present invention and are not used 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] Embodiment 11

[0082]

[0083]

[0084] Comparative Example 1

[0085] The difference between Comparative Example 1 and Example 1 is that the end-capping agent 1-octadecyl alcohol is not added, and the other parts remain unchanged.

[0086] Comparative Example 2

[0087] The difference between Comparative Example 1 and Example 1 is that an equal mass of n-heptanol is used to replace the original end-capping agent 1-octadecyl alcohol, and the other contents remain unchanged.

[0088] Comparative Example 3

[0089] The difference between Comparative Example 1 and Example 8 is that an equal mass of PBEA-Mn2000 (EG:BDO=1:1) is used to replace the original polyester polyol PBEA-Mn2200 (EG:BDO=1:1), and the other contents remain unchanged.

[0090] The specific embodiments and comparative examples of the present invention are prepared by a 14-section twin-screw extruder. The isocyanate, polyester polyol, chain extender, and end-capping agent in the weight proportions of the raw materials in each embodiment are fed into the first section of the twin-screw reaction extruder through a perfusion system. After the reaction, the melt passes through a die head and is pelletized underwater. After drying, a thermoplastic polyurethane elastomer can be obtained.

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

[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 in accordance with HG / T 5500-2019;

[0094] Tensile strength: tested in accordance with HG / T 5500-2019;

[0095] Tear strength: tested in accordance with HG / T 5500-2019;

[0096] Melt flow rate: tested in accordance with HG / T 5500-2019;

[0097] Precipitation performance: Place the thermoplastic polyurethane elastomer sample at 70°C for one week and observe the precipitation on the sample surface;

[0098] Processing performance: Thermoplastic polyurethane elastomer particles are injection molded at 200°C using a K90VT / MJ4711 injection molding machine, and the demoulding time of the test piece is recorded (i.e., the test piece remains unchanged when pressed by hand after demolding). The shorter the demoulding time, the faster the molding speed and the better the processability.

[0099] The performance comparison of the embodiment and the comparative example is shown in Table 1 below:

[0100] Table 1:

[0101]

Claims

1. A high-flow, easy-to-process thermoplastic polyurethane elastomer, characterized in that The invention comprises a reactant obtained by reacting a polyisocyanate, a polymer polyol, a chain extender and a capping agent; wherein the number average molecular weight of the polymer polyol is above 2200 g / mol, and the capping agent comprises a monohydric alcohol having more than 10 carbon atoms.

2. A high-flow, easy-to-process thermoplastic polyurethane elastomer according to claim 1, characterized in that The high-flow and easy-to-process thermoplastic polyurethane elastomer also contains an antioxidant, which includes one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol, tris(nonylphenyl)phosphite, and triisodecyl phosphite.

3. A high-flow, easy-to-process thermoplastic polyurethane elastomer according to claim 1 or 2, characterized in that The polymer polyol includes polyester polyol and does not contain polyether polyol; the polyester polyol includes one or more polyester polyols obtained by condensation reaction of at least two diols and at least one dibasic acid; the average hydroxyl functionality of the polyester polyol is 2; the number average molecular weight of the polymer polyol is 2500-4000 g / mol, and more preferably 2500-3500 g / mol.

4. A high-flow, easy-to-process thermoplastic polyurethane elastomer according to claim 3, characterized in that The diols include diol A and diol B, wherein the carbon number of diol A is 4 to 8, the carbon number of diol B is 2 to 3, and the molar ratio of diol A to diol B is 1:1 to 1:2; wherein the diol A includes one or more of butanediol, pentanediol, neopentyl glycol, hexanediol, heptanediol, and octanediol, preferably, the diol A includes butanediol and / or hexanediol; the diol B includes one or a combination of ethylene glycol and propylene glycol; and the dibasic acid includes one or more of succinic acid, glutaric acid, and adipic acid.

5. A high-flow, easy-to-process thermoplastic polyurethane elastomer according to claim 1 or 2, characterized in that The chain extender includes a small molecule diol, including one or more of ethylene glycol, propylene glycol, butanediol, pentanediol, and hexanediol; the end capping agent includes a straight-chain aliphatic monohydric alcohol having a carbon number of 10 to 20; wherein the straight-chain aliphatic monohydric alcohol includes at least one of 1-nonanol, n-dodecanol, 1-tridecanol, n-tetradecanol, 1-hexadecanol, 1-octadecanol, and 1-eicosanol, preferably at least one of n-tetradecanol, 1-hexadecanol, 1-octadecanol, and 1-eicosanol.

6. A high-flow, easy-to-process thermoplastic polyurethane elastomer according to claim 1 or 2, characterized in that The polyisocyanate includes one or more of diphenylmethane diisocyanate MDI, toluene diisocyanate TDI, hexamethylene diisocyanate HDI, diisocyanate dicyclohexylmethane HMDI, isophorone diisocyanate IPDI, p-phenylene diisocyanate PPDI and / or derivatives and / or modified polymers.

7. A high-flow, easy-to-process thermoplastic polyurethane elastomer according to claim 6, characterized in that The polyisocyanate derivatives include polyisocyanate dimers and / or polyisocyanate trimers; the polyisocyanate modified polymers include carbodiimide modified isocyanate polymers.

8. A high-flow, easy-to-process thermoplastic polyurethane elastomer according to claim 7, characterized in that The isocyanate index is 0.95:1 to 1.05:1; the isocyanate index is the molar ratio of the NCO group in the polyisocyanate to the group reactive to NCO in the polymer polyol, the chain extender and the end-capping agent.

9. A high-flow, easy-to-process thermoplastic polyurethane elastomer according to claim 1, characterized in that By weight, the high flow and easy processing thermoplastic polyurethane elastomer includes: Preferably, the mass proportion of the end-capping agent in the total mass of the polyisocyanate, the polymer polyol, the chain extender and the end-capping agent does not exceed 0.5%.

10. An application of the high-flow and easy-to-process thermoplastic polyurethane elastomer as claimed in claim 1 or 2, characterized in that It is applied to the thermoplastic polyurethane elastomer encapsulated modified material.

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