Block copolymer, polyamide elastomer and application thereof

Abstract

The invention relates to a block copolymer, a polyamide elastomer and application thereof, the block copolymer comprises a hard segment and a soft segment, the hard segment comprises a polyamide block, and the soft segment comprises a polyether block; wherein the polyamide block is obtained through reaction of pentamethylene diamine and long carbon chain dibasic acid, and the long carbon chain dibasic acid comprises more than three long carbon chain dibasic acid with odd number of carbon atoms or more than three long carbon chain dibasic acid with even number of carbon atoms. The block copolymer provided by the embodiment of the invention has excellent comprehensive performance, and can greatly improve the elongation at break and notch impact strength of a material when being used as a toughening agent of a polyamide material.

Description

TECHNICAL FIELD

[0001] The present application relates to thermoplastic elastomers, in particular to a polyamide elastomer and its application. BACKGROUND

[0002] At present, the widely used toughening agent in the toughening of polyamide plastic products is a vinyl elastomer, such as modified POE and modified EPDM, however, the addition of these toughening agents requires additional addition of a compatibilizer, and therefore, it is necessary to develop a more suitable toughening agent for polyamide plastic products. SUMMARY

[0003] To overcome at least one of the above-mentioned defects of the prior art, in a first aspect, an embodiment of the present application provides a block copolymer, comprising a hard segment and a soft segment, the hard segment comprising a polyamide block, and the soft segment comprising a polyether block; wherein the polyamide block is obtained by reacting pentanediamine and long-chain dibasic acid, and the long-chain dibasic acid comprises three or more long-chain dibasic acids with odd number of carbon atoms or three or more long-chain dibasic acids with even number of carbon atoms.

[0004] In a second aspect, an embodiment of the present application provides a polyamide elastomer, comprising the above-mentioned block copolymer.

[0005] In a third aspect, an embodiment of the present application provides a preparation method of a polyamide elastomer, comprising: preparing a block copolymer by reacting reactant raw materials; wherein the reactant raw materials comprise a hard segment raw material and a soft segment raw material, the hard segment raw material comprises a polyamide prepolymer, and the soft segment raw material comprises a polyether, the polyamide prepolymer is obtained by reacting pentanediamine and long-chain dibasic acid, and the long-chain dibasic acid comprises three or more long-chain dibasic acids with odd number of carbon atoms or three or more long-chain dibasic acids with even number of carbon atoms.

[0006] In a fourth aspect, an embodiment of the present application provides a toughened polyamide composition, comprising a polyamide and the above-mentioned block copolymer or the above-mentioned polyamide elastomer.

[0007] In a fifth aspect, an embodiment of the present application provides the above-mentioned block copolymer or the above-mentioned polyamide elastomer as a toughening agent.

[0008] The block copolymer or the polyamide elastomer of an embodiment of the present application has excellent comprehensive performance and is used as a toughening agent for polyamide materials, which can greatly improve the elongation at break and notched impact strength of the materials. DETAILED DESCRIPTION

[0009] Typical embodiments embodying the features and advantages of the present application will be described in detail in the following description. It should be understood that the present application can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these described embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art. Like reference numerals refer to like elements throughout the specification. It will be understood that when a term is referred to as "about" a value, it is intended to convey that the term refers to the nominal value and also to variations that fall within common levels of error for the devices and / or methods at issue. Unless otherwise defined, all terms of art used herein are intended to refer to terms of art as commonly understood by one of ordinary skill in the art and to terms with the same meanings as are attributed to such terms by dictionaries.

[0010] One embodiment of the present application provides a block copolymer, comprising a hard segment and a soft segment, the hard segment comprising a polyamide block, and the soft segment comprising a polyether block; wherein the polyamide block (or its raw material, a polyamide prepolymer) is obtained by reacting pentanediamine and long-chain dicarboxylic acid, the long-chain dicarboxylic acid comprising three or more long-chain dicarboxylic acids with an odd number of carbon atoms or three or more long-chain dicarboxylic acids with an even number of carbon atoms.

[0011] In one embodiment, the long-chain dicarboxylic acid is selected from linear aliphatic dicarboxylic acids containing 9-18 carbon atoms.

[0012] In one embodiment, the long-chain dicarboxylic acid comprises any three of sebacic acid, dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid. Further, the long-chain dicarboxylic acid can comprise sebacic acid, dodecanedioic acid, tetradecanedioic acid, or the long-chain dicarboxylic acid can comprise sebacic acid, dodecanedioic acid, hexadecanedioic acid.

[0013] In one embodiment, the long-chain dicarboxylic acid comprises any three of azelaic acid, undecanedioic acid, tridecanedioic acid, pentadecanedioic acid, heptadecanedioic acid. Further, the long-chain dicarboxylic acid can comprise undecanedioic acid, tridecanedioic acid, pentadecanedioic acid.

[0014] In one embodiment, the molar ratio of the long-chain dicarboxylic acid and pentanediamine is 1 or more, and further can be 1-2.5 or 1.1-2, for example 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 2.1, 2.2, 2.3, 2.4.

[0015] In one embodiment, the polyamide block (or its raw material, a polyamide prepolymer) is obtained by reacting pentanediamine, sebacic acid, dodecanedioic acid, and hexadecanedioic acid. Further, the molar ratio of sebacic acid, dodecanedioic acid, and hexadecanedioic acid can be 1:(1.5-4):(1-1.5), and further can be 1:(2-3):(1.2-1.3), for example 1:2:1, 1:2.5:1, 1:3:1, 1:3.5:1, 1:2:1.5, 1:2.5:1.5, 1:3:1.5, 1:3.5:1.5.

[0016] In an embodiment, the polyamide block (or its raw material polyamide prepolymer) is obtained by reacting pentanediamine, decanedioic acid, dodecanedioic acid and tetradecanedioic acid. Further, the molar ratio of decanedioic acid, dodecanedioic acid and tetradecanedioic acid can be 1 : (1.5-4) : (1-1.5), further can be 1 : (2-3) : (1.2-1.3), for example 1 :2:1, 1 :2.5:1, 1 :3:1, 1 :3.5:1, 1 :2:1.5, 1 :2.5:1.5, 1 :3:1.5, 1 :3.5:1.5.

[0017] In an embodiment, the soft segment comprises a polyether block, and optionally a polyester structure, which can be obtained by reacting a polyol.

[0018] In an embodiment, the soft segment is from a combination of a polyether and a polyol, for example, the soft segment is from a combination of a polyether diol and a polyol.

[0019] In an embodiment, the polyether block as the soft segment can be derived from one polyether or more than two polyethers.

[0020] In an embodiment, the polyether can be derived from one or more of diol, triol, tetraol. For example, the polyether derived from diol can be polyethylene glycol (PEG), polypropylene glycol (PPG), polytetramethylene glycol (PTMG) or polytetrahydrofuran (PTMEG); the polyether derived from triol can be polyglycerol; the polyether derived from tetraol can be polytetramethylene ether glycol or polytetrahydrofuran ether triol.

[0021] In an embodiment, the polyether can have a number average molecular weight of 200-5000, further can have a number average molecular weight of 200-2000, and further can have a number average molecular weight of 1000-2000.

[0022] In an embodiment, the polyether can comprise one or more of PTMEG1000, PTMEG2000, PEG400, PPG1000. Wherein, 1000 in PTMEG1000 represents the approximate number average molecular weight of PTMEG, and other definitions are similar.

[0023] In an embodiment, the soft segment is a combination of more than two polyethers, for example, a combination of PTMEG1000 and PTMEG2000.

[0024] In an embodiment, the raw material for preparing the block copolymer comprises a polyamide prepolymer and a polyether.

[0025] In an embodiment, the raw material for preparing the block copolymer comprises a polyamide prepolymer, a polyether and a polyol.

[0026] In one embodiment, the polyol includes one or more of glycerol, polyether triol (or glycerol polyether), pentaerythritol, trimethylolpropane (TMP). Further, the polyether triol can have a number average molecular weight of 200-6000, such as 500, 1000, 2000, 3000, 4000, 5000.

[0027] In one embodiment, the hard segment of the block copolymer has a number average molecular weight of 1000-2000, further 1400-1600, such as 1420, 1430, 1440, 1450, 1470, 1480, 1490, 1500, 1510, 1520, 1550, 1560, 1570, 1580.

[0028] In one embodiment, the soft segment of the block copolymer has a number average molecular weight of 200-5000, further 1000-2000, such as 400, 500, 600, 800, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500.

[0029] In one embodiment, the molar ratio of the hard segment and the soft segment of the block copolymer can be 0.85-2:1, further 0.85-1.3:1, and further 0.9-1.1:1, such as 0.8:1, 0.89:1, 0.9:1, 1:1, 1.05:1, 1.09:1, 1.1:1, 1.15:1, 1.17:1, 1.2:1, 1.25:1, 1.3:1, 1.5:1, 1.6:1, 1.8:1.

[0030] In one embodiment of the present application, by selecting specific hard segment and soft segment, a block copolymer with specific relative viscosity and melting point can be obtained.

[0031] In one embodiment of the present application, a polyamide elastomer is provided, which includes the above-mentioned block copolymer.

[0032] In one embodiment, the relative viscosity of the block copolymer and / or the polyamide elastomer is 2.1-4.5, further 2.1-2.7, such as 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.2, 3.3, 3.5, 3.6, 3.8, 4.0, 4.2, 4.4. The above-mentioned relative viscosity is detected by Ubbelohde viscometer, the mobile phase is formic acid with a mass concentration of 98%, and the temperature is 25°C.

[0033] In an embodiment, the number average molecular weight of the block copolymer and / or the polyamide elastomer can be from 10,000 to 70,000, further from 20,000 to 50,000, and still further from 20,000 to 42,000, such as 10,000, 20,000, 21,000, 22,000, 25,000, 26,000, 27,000, 28,000, 29,000, 30,000, 31,000, 32,000, 33,000, 34,000, 35,000, 36,000, 40,000, 41,000, 41,100, 50,000, 60,000, or 70,000.

[0034] In an embodiment, the melting point of the block copolymer and / or the polyamide elastomer can be from 130 °C to 230 °C, further from 150 °C to 180 °C, and still further from 160 °C to 175 °C, such as 155 °C, 158 °C, 160 °C, 163 °C, 165 °C, 168 °C, 170 °C, 172 °C, 173 °C, 175 °C, 178 °C, 190 °C, 200 °C, 210 °C, 220 °C.

[0035] In an embodiment, the polyamide elastomer further comprises an additive, which can be one or more of a lubricant, a nucleating agent, an antioxidant, for example. The additive can be added as needed according to the actual use scenario.

[0036] In an embodiment, the lubricant can include one or more of an aliphatic amide, an aliphatic alcohol, an aliphatic bisamide, and a polyethylene wax. The nucleating agent can include one or more of silica, talc, kaolin, and clay. The antioxidant can include one or more of a hindered phenol compound, a hydroquinone compound, a hydroquinone compound, a phosphite compound and its substitutes, an iodide, a copper salt.

[0037] In an embodiment, the mass content of the additive in the polyamide elastomer is 5% or less, further can be greater than 0 and less than or equal to 3%, such as 0.1%, 0.2%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%.

[0038] In an embodiment, the density of the block copolymer and / or the polyamide elastomer can be from 1.01 g / mL to 1.10 g / mL, such as 1.02 g / mL, 1.03 g / mL, 1.04 g / mL, 1.05 g / mL, 1.07 g / mL, 1.09 g / mL.

[0039] In an embodiment, the Shore hardness of the block copolymer and / or the polyamide elastomer can be from 40D to 55D, further from 40D to 50D, such as 40D, 41D, 42D, 45D, 46D, 48D, 50D, 51D, 53D, 55D.

[0040] In one embodiment, the elongation at break of the block copolymer and / or polyamide elastomer can be 200% or more, and further can be 500-700%, for example 500%, 510%, 530%, 540%, 550%, 570%, 580%, 590%, 600%, 620%, 630%, 640%, 650%, 660%, 700%.

[0041] In one embodiment, the tensile strength of the block copolymer and / or polyamide elastomer is 30-60 MPa, and further can be 30-45 MPa, for example 32 MPa, 35 MPa, 36 MPa, 39 MPa, 40 MPa, 41 MPa, 43 MPa, 45 MPa, 47 MPa, 48 MPa, 50 MPa, 52 MPa, 54 MPa, 57 MPa, 59 MPa.

[0042] In one embodiment, the notched impact strength of the block copolymer and / or polyamide elastomer is 10 kJ / m 2 More preferably, the NB (not broken).

[0043] One embodiment of the present application provides a method for preparing the above-mentioned block copolymer or polyamide elastomer, comprising: preparing the block copolymer by reacting raw materials; wherein the raw materials comprise hard segment raw materials and soft segment raw materials, the hard segment raw materials comprise the aforementioned polyamide prepolymer, and the soft segment raw materials comprise the aforementioned polyether.

[0044] In one embodiment, in the prepared block copolymer, the polyamide prepolymer of the hard segment raw materials forms the aforementioned polyamide block after reaction, and the polyether of the soft segment raw materials forms the aforementioned polyether block after reaction.

[0045] In one embodiment, the hard segment raw materials and the soft segment raw materials are reacted at 200-260°C and a vacuum degree of -0.01 to -0.09 MPa for 1-5 h, and then the absolute pressure is reduced to 1000 Pa or less (preferably 500 Pa or less) within 0.5-3 h, and the reaction is continued for 1-10 h. In this case, the reaction time at a vacuum degree of -0.01 to -0.09 MPa can be 2 h, 3 h, or 4 h, the pressure reduction time can be 1 h or 2 h, and the reaction time at 1000 Pa or less can be 2 h, 3 h, 5 h, 6 h, or 8 h.

[0046] In one embodiment, the polyamide prepolymer as the hard segment raw material is obtained by reacting the aforementioned pentanediamine and long-chain dicarboxylic acid.

[0047] In one embodiment, the molar ratio of the long-chain dicarboxylic acid to the pentanediamine is 1 or more.

[0048] In an embodiment, the molar ratio of long carbon chain dibasic acid to pentanediamine can be 1-2.5:1, further can be 1.1-2:1, for example 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2.2:1, 2.3:1.

[0049] In an embodiment, the molar ratio of long carbon chain dibasic acid to pentanediamine can be 1-1.5:1, further can be 1-1.3:1, for example 1.2:1, 1.25:1.

[0050] In an embodiment, the soft segment raw material comprises polyether and polyol.

[0051] In an embodiment, the molar ratio of polyether to polyol can be (1-2):(0.05-0.2), further can be (1-1.5):(0.05-0.15), further can be (1-1.1):(0.05-0.15), for example 1:0.08, 1:0.1, 1:0.12, 1:0.15, 1:0.18, 1.5:0.1, 1.5:0.12, 1.5:0.15, 1.5:0.18.

[0052] In an embodiment, the molar ratio of hard segment raw material to soft segment raw material can be 0.85-2:1, further can be 0.85-1.3:1, further can be 0.9-1.1:1, for example 0.89:1, 0.9:1, 1:1, 1.05:1, 1.09:1, 1.1:1, 1.15:1, 1.17:1, 1.2:1, 1.25:1, 1.3:1.

[0053] In an embodiment, the method for preparing the block copolymer or polyamide elastomer comprises the following steps:

[0054] S1: reacting pentanediamine and long carbon chain dibasic acid to obtain polyamide prepolymer;

[0055] S2: reacting the polyamide prepolymer with soft segment raw material to obtain block copolymer.

[0056] In an embodiment, step S1 comprises:

[0057] S11: mixing pentanediamine, long carbon chain dibasic acid, optional additive and water to prepare polyamide salt solution;

[0058] S12: heating the polyamide salt solution to 200-250℃, the pressure is 1.5-3.0 MPa, and water is discharged and exhausted;

[0059] S13: continue to increase the temperature of the system to 240-270℃, vacuum to -0.01- -0.1MPa, and maintain for 5-60min, to obtain a polyamide prepolymer.

[0060] In an embodiment, the reaction system of step S1 includes a first catalyst, which can be a phosphorus-based catalyst, and the phosphorus-based catalyst can include one or more of phosphoric acid, phosphorous acid, trimethyl phosphite, triphenyl phosphite, trimethyl phosphate, triphenyl phosphate, sodium hypophosphite, sodium hypophosphorous acid, zinc hypophosphite, calcium hypophosphite, and potassium hypophosphite.

[0061] In an embodiment, the first catalyst can be added during the preparation of the polyamide salt solution in step S11.

[0062] In an embodiment, the temperature of step S12 can be 210℃, 215℃, 220℃, 225℃, 230℃, 240℃; and the pressure can be 1.6MPa, 1.8MPa, 2MPa, 2.2MPa, 2.5MPa, 2.8MPa.

[0063] In an embodiment, the temperature of step S13 can be 245℃, 250℃, 255℃, 260℃, 265℃; the vacuum can be -0.02MPa, -0.05MPa, -0.06MPa, -0.07MPa, -0.08MPa; and the holding time can be 10min, 15min, 20min, 25min, 30min, 40min, 50min.

[0064] In an embodiment, the number average molecular weight of the polyamide prepolymer prepared in step S1 is 1000-2000, and further can be 1400-1600.

[0065] In an embodiment, step S2 includes mixing the hard segment raw material and the soft segment raw material at 200-260℃, adding a second catalyst, and reacting for 1-5h under a vacuum of -0.01- -0.09MPa, and then reducing the absolute pressure to below 1000Pa (preferably below 500Pa) within 0.5-3h, and continuing to react for 1-10h.

[0066] In an embodiment, in step S2, the hard segment raw material and the soft segment raw material are first mixed at 200-260℃ and maintained for 60-120min, and then the second catalyst is added. The holding time of the hard segment raw material and the soft segment raw material mixture can be 70min, 80min, 90min, 100min, 110min.

[0067] In an embodiment, the method for preparing the block copolymer and / or the polyamide elastomer includes the following steps:

[0068] S1: mixing pentanediamine, long carbon chain dibasic acid, first catalyst and water to obtain a polyamide salt solution; heating the polyamide salt solution to 200-250℃, increasing the pressure to 1.5-3.0 MPa, discharging water and reducing the pressure, increasing the temperature to 240-270℃, vacuumizing to -0.01 to -0.08 MPa, and maintaining for 5-60 min;

[0069] S2: adding soft segment raw material and second catalyst to the system, stirring and reacting for 1-5 h under a vacuum of -0.01 to -0.1 MPa, then reducing the absolute pressure to below 1000 Pa (preferably below 500 Pa) within 0.5-3 h, continuing to react for 1-10 h, and discharging.

[0070] In an embodiment, the second catalyst can be selected from one or more of phosphorus-based catalyst, titanium-based catalyst, zirconium-based catalyst, antimony-based catalyst, germanium-based catalyst.

[0071] In an embodiment, the phosphorus-based catalyst can include one or more of phosphoric acid, phosphorous acid, trimethyl phosphite, triphenyl phosphite, trimethyl phosphate, triphenyl phosphate, sodium hypophosphite, sodium hypophosphorous acid, zinc hypophosphite, calcium hypophosphite, potassium hypophosphite; the titanium-based catalyst can include one or more of tetrabutyl titanate, tetraethyl titanate and tetrapropyl titanate; the zirconium-based catalyst can include tetrabutyl zirconate and / or tetrapropyl zirconate; the antimony-based catalyst can be ethylene glycol antimony; and the germanium-based catalyst can be GeO2.

[0072] In an embodiment, the second catalyst used is in a molar amount of 0.1-5% of the total moles of the hard segment raw material and the soft segment raw material, for example 0.5%, 0.8%, 1%, 2%, 3%, 4%.

[0073] In an embodiment, the preparation process of the block copolymer or the polyamide elastomer is carried out under vacuum, nitrogen or inert gas, wherein the inert gas includes one or more of neon, argon, krypton, xenon, radon.

[0074] The block copolymer of an embodiment of the present application is a bio-based block copolymer, i.e., the polymerized monomers used include bio-based monomers, for example, the pentanediamine is bio-based pentanediamine, which means that the pentanediamine is synthesized from compounds derived from biomass such as glucose, lysine, etc. through enzyme reaction, yeast reaction or fermentation reaction, etc. in the monomer synthesis process. The bio-based content of the bio-based pentanediamine can be determined by a method of measuring the radioactive C14 content, for example, the standard ASTM-D6866 method of the American Society for Testing Materials. Accordingly, the polyamide elastomer of an embodiment of the present application is a bio-based polyamide elastomer.

[0075] One embodiment of the present application provides a product comprising the block copolymer and / or polyamide elastomer described above.

[0076] One embodiment of the present application provides a product, the raw material of which comprises the block copolymer and / or polyamide elastomer described above.

[0077] One embodiment of the present application provides a toughened polyamide composition comprising a polyamide and the block copolymer and / or polyamide elastomer described above. The block copolymer and / or polyamide elastomer described above functions as a toughening agent. Further, the polyamide can be a polyamide PA5X or a polyamide in the polyamide PA6X series, such as polyamide 6, polyamide 66, polyamide 610, polyamide 612, polyamide 56, polyamide 510, polyamide 512, and the like.

[0078] In one embodiment, the toughened polyamide composition further comprises other auxiliary agents, such as an antioxidant and / or a lubricant.

[0079] In one embodiment, the mass content of the block copolymer or polyamide elastomer in the toughened polyamide composition can be 10-35%, such as 15%, 20%, 25%, 28%, 29%, 30%, 31%, 32%.

[0080] In one embodiment, the elongation at break of the toughened polyamide composition (or the toughened polyamide of its molded material) can be 200-300%, further can be 230-290%, such as 235%, 238%, 240%, 243%, 245%, 250%, 259%, 260%, 261%, 265%, 270%, 276%, 280%, 281%, 285%, 287%.

[0081] In one embodiment, the tensile strength of the toughened polyamide composition (or the toughened polyamide of its molded material) can be 40-55 MPa, further can be 45-51 MPa, such as 46 MPa, 47 MPa, 48 MPa, 49 MPa, 50 MPa.

[0082] In one embodiment, the notched impact strength of the toughened polyamide composition (or the toughened polyamide of its molded material) can be 30-50 kJ / m 2 , further can be 35-41 kJ / m 2 , such as 36 kJ / m 2 , 37 kJ / m 2 , 38 kJ / m 2 , 39 kJ / m 2 , 40 kJ / m 2 , 42 kJ / m 2 , 45 kJ / m2 .

[0083] One embodiment of the present application provides the use of the above-mentioned block copolymer and / or polyamide elastomer as a toughening agent, in particular as a toughening agent for polyamide.

[0084] One embodiment of the present application can obtain a bio-based polyamide with a specific relative viscosity and melting point by selecting specific hard segments and soft segments, so as to meet different use requirements according to specific application scenarios.

[0085] The block copolymer / polyamide elastomer of one embodiment of the present application has stable monomer sources and low cost.

[0086] The preparation method of the block copolymer or polyamide elastomer of one embodiment of the present application has low cost, and the bio-based raw materials meet the sustainable development policy, thereby reducing the dependence on fossil energy and being conducive to building a low-carbon society.

[0087] The block copolymer / polyamide elastomer of one embodiment of the present application has a relatively low melting point and a relatively high strength.

[0088] The block copolymer / polyamide elastomer of one embodiment of the present application has excellent comprehensive performance and stable monomer sources, solves the problems of high cost, unstable monomer sources or low comprehensive performance of the polyamide elastomers in the prior art, widens the use scenarios of the elastomers, and has a high commercial value due to the low manufacturing cost.

[0089] The block copolymer / polyamide elastomer of one embodiment of the present application has excellent performance and stable monomer sources, widens the application scenarios, and has a high commercial value.

[0090] The block copolymer or polyamide elastomer of one embodiment of the present application can greatly improve the elongation at break and notched impact strength of a resin when used as a toughening agent, in particular a toughening agent for a polyamide resin.

[0091] Hereinafter, the preparation of the block copolymer of one embodiment of the present application will be further described in combination with examples. The raw materials and test methods used in the examples and comparative examples are as follows. The test data involved in the present text are measured by the corresponding test methods as follows:

[0092] Test Method

[0093] 1. Density

[0094] The density is measured according to international standard ISO 1183.

[0095] 2. Relative viscosity

[0096] Relative viscosity is measured at 25℃ by using Ubbelohde viscometer, relative viscosity ηr = t / t0; wherein t is the flow time of sample solution, t0 is the flow time of formic acid with mass concentration of 98% as solvent.

[0097] 3. Shore hardness

[0098] Shore hardness D is measured according to international standard ISO 7619.

[0099] 4. Elongation at break, tensile strength

[0100] Elongation at break, tensile strength is measured according to international standard ISO 527.

[0101] 5. Notched impact strength

[0102] Notched impact strength is measured with reference to test standard ISO 180.

[0103] 6. Melting point

[0104] Melting point is measured according to standard ISO 11357.

[0105] 7. Number average molecular weight

[0106] Number average molecular weight is measured according to gel permeation chromatography (GPC).

[0107] Raw Materials

[0108] Pentanediamine (biobased content 100%); decanedioic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid are purchased from Kaisai (Jinxiang) Biomatierials Co., Ltd., all of which are prepared by biological method; polytetrahydrofuran (PTMEG) is purchased from Changlian Chemical Industry (Changchun).

[0109] Example 1

[0110] Preparation of polyamide elastomer

[0111] S1: Under the condition of nitrogen, pure water, pentanediamine, long-chain diacid, and catalyst sodium hypophosphite are mixed, wherein the molar ratio of long-chain diacid and pentanediamine is 1.23, to obtain a polyamide salt solution; the polyamide salt solution is transferred to a polymerization kettle, heated to 220℃, the pressure in the kettle is raised to 1.7 MPa, water is discharged, and the temperature is continuously raised to 250℃, then vacuum is extracted to a pressure of-0.06 MPa, and maintained for 20 min, to obtain a hard segment polyamide prepolymer, which is dried for standby use.

[0112] S2: The hard segment polyamide prepolymer and the soft segment raw material prepared in step S1 were placed in a polymerization kettle under nitrogen, and mixed at 240°C for 90 min; then tetrabutyl titanate was added into the system as a catalyst, and then stirred for 2 h under a vacuum of -0.06 MPa, and then the absolute pressure was reduced to below 500 Pa within 1 h, and the reaction was continued for 1 h, and then the pressure was increased to a slight positive pressure by nitrogen, and the product was discharged and pelletized to obtain a polyamide elastomer; wherein the types of the soft segment raw material and the molar ratio thereof to the hard segment raw material are shown in Table 1.

[0113] Preparation of the toughened polyamide

[0114] The 68 parts by weight of PA612, 30 parts by weight of the polyamide elastomer, 1 part by weight of antioxidant 1098, and 1 part by weight of lubricant ethylene bis-stearamide were mixed and then extruded through a double-screw extruder to obtain a toughened polyamide.

[0115] Examples 2 to 8

[0116] Examples 2 to 8 were prepared by using the same process as in Example 1 to prepare a polyamide elastomer and a toughened polyamide, and the main difference was that the amounts of the raw materials used were different, and the types of the long-chain diacids were different, as shown in Table 1.

[0117] Comparative Example 1

[0118] This example was prepared by using the same process as in Example 8 to prepare a polyamide elastomer and a toughened polyamide, and the main difference was that the molar ratio of the hard segment raw material to the soft segment raw material in step S2 was different, as shown in Table 1.

[0119] Comparative Example 2

[0120] This example was prepared by using the same process as in Example 1 to prepare a polyamide elastomer and a toughened polyamide, and the main difference was that the amounts of the raw materials used were different, and the types of the long-chain diacids were different, as shown in Table 1.

[0121] Comparative Example 3

[0122] This example was prepared by using the same process as in Example 1 to prepare a polyamide elastomer and a toughened polyamide, and the main difference was that the amounts of the raw materials used were different, and the types of the long-chain diacids were different, as shown in Table 1.

[0123] Comparative Example 4

[0124] The 68 parts by weight of PA612 (the same as the PA612 in Example 1), 1 part by weight of antioxidant 1098, and 1 part by weight of lubricant ethylene bis-stearamide were mixed and then extruded through a double-screw extruder to obtain a non-toughened polyamide.

[0125] The polyamide elastomers, toughened polyamides (or non-toughened polyamides) prepared from each of the examples and the comparative examples were subjected to relevant performance tests according to the aforementioned test methods, and the results are shown in Tables 2 and 3.

[0126]

[0127]

[0128] Examples 1 to 8 of the present application all used pentanediamine and three long-chain diacids with odd number of carbon atoms or three long-chain diacids with even number of carbon atoms to prepare polyamide hard segments. According to the data in Table 2, the polyamide elastomers of Examples 1 to 8 all have better mechanical properties and lower melting points.

[0129] Further, according to Table 3, the polyamide elastomers of Examples 1 to 8 as toughening agents for polyamide 612 can greatly improve the elongation at break and notched impact strength of the material compared with the polyamide 612 of Comparative Example 4 which does not use a toughening agent.

[0130] The types of long-chain diacids used in Comparative Examples 2 and 3 are different from those of Examples 1 to 8. Although the polyamide elastomers prepared from Comparative Examples 2 and 3 also have better tensile strength, according to the data in Table 3, the polyamide elastomers of Comparative Examples 2 and 3 as toughening agents for polyamide 612 have significantly lower improvement in the elongation at break and notched impact strength of the material than Examples 1 to 8.

[0131] Unless specifically defined, the terms used in the present application are understood by those skilled in the art in the usual meaning.

[0132] The embodiments described in the present application are for illustrative purposes only and are not intended to limit the scope of protection of the present application. Those skilled in the art can make various other replacements, changes and improvements within the scope of the present application, and thus the present application is not limited to the above-described embodiments but is defined only by the claims.

Claims

1. A block copolymer comprising hard segments and soft segments, wherein the hard segments comprise polyamide blocks and the soft segments comprise polyether blocks; wherein, The polyamide block is obtained by reacting pentanediamine with a long-chain dicarboxylic acid, wherein the long-chain dicarboxylic acid includes three or more long-chain dicarboxylic acids with an odd number of carbon atoms or three or more long-chain dicarboxylic acids with an even number of carbon atoms.

2. The block copolymer according to claim 1, wherein, The long-chain dicarboxylic acid is selected from straight-chain aliphatic dicarboxylic acids containing 9 to 18 carbon atoms; and / or, The number-average molecular weight of the hard segments is 1000–2000; and / or, The molar ratio of hard segments to soft segments in the block copolymer is 0.85 to 2:1; and / or, The number-average molecular weight of the block copolymer is 10,000 to 70,000; and / or, The block copolymer has a melting point of 130–230°C; and / or, The tensile strength of the block copolymer is 30–60 MPa.

3. The block copolymer according to claim 1, wherein, The long-chain dicarboxylic acid includes any three of the following: sebacic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, and octadecanoic acid; or, the long-chain dicarboxylic acid includes any three of the following: azelaic acid, undecanoic acid, tridecanoic acid, pentadecanoic acid, and heptadecanoic acid; and / or, The soft segment is obtained by reacting a polyether with an optional polyol; and / or, The block copolymer has a melting point of 150–180°C; and / or, The Shore hardness of the block copolymer is 40D to 55D; and / or, The block copolymer has an elongation at break of 500–700%.

4. The block copolymer according to claim 3, wherein, The long-chain dicarboxylic acid includes sebacic acid, dodecanoic acid, and hexadecanoic acid, wherein the molar ratio of sebacic acid, dodecanoic acid, and hexadecanoic acid is 1:(1.5-4):(1-1.5); and / or, The polyol includes one or more of glycerol, polyether triol, pentaerythritol, and trimethylolpropane; and / or, The polyether comprises one or more of polyethylene glycol, polypropylene glycol, polybutylene glycol, polytetrahydrofuran, polyglycerol, and polybutadiene; and / or, The number-average molecular weight of the soft segments is 200–5000; and / or, The number-average molecular weight of the hard segments is 1400–1600; and / or, The molar ratio of hard segments to soft segments in the block copolymer is 0.85 to 1.3:

1.

5. The block copolymer according to claim 1, wherein, The long-chain dicarboxylic acid includes sebacic acid, dodecanoic acid, and tetradecanoic acid, wherein the molar ratio of sebacic acid, dodecanoic acid, and tetradecanoic acid is 1:(1.5-4):(1-1.5); and / or, The number-average molecular weight of the soft segments is 1000–2000; and / or, The molar ratio of hard segments to soft segments in the block copolymer is 0.9–1.1:1; and / or, The relative viscosity of the block copolymer is 2.1 to 4.5; and / or, The number-average molecular weight of the block copolymer is 20,000 to 50,000.

6. The block copolymer according to claim 1, wherein the relative viscosity is 2.1 to 2.7; and / or, The number-average molecular weight of the block copolymer is 20,000 to 42,000; and / or, The block copolymer has a melting point of 160–175°C; and / or, The Shore hardness of the block copolymer is 40D to 50D; and / or, The tensile strength of the block copolymer is 30–45 MPa.

7. A polyamide elastomer comprising any one of the block copolymers according to claims 1 to 6.

8. A method for preparing a polyamide elastomer, comprising: The reactants are prepared by reacting reactants; wherein the reactants include hard segment raw materials and soft segment raw materials, the hard segment raw materials include polyamide prepolymer, and the soft segment raw materials include polyether, wherein the polyamide prepolymer is obtained by reacting pentanediamine with a long-chain dicarboxylic acid, and the long-chain dicarboxylic acid includes three or more long-chain dicarboxylic acids with an odd number of carbon atoms or three or more long-chain dicarboxylic acids with an even number of carbon atoms.

9. A toughened polyamide composition comprising a polyamide and a block copolymer according to any one of claims 1 to 6 or a polyamide elastomer according to claim 7.

10. The use of the block copolymer of any one of claims 1 to 6 or the polyamide elastomer of claim 7 as a toughening agent.

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