Furandicarboxylic acid-based polyamide, its production method, and furandicarboxylic acid-based polyamide composition

Abstract

The present invention discloses a furandicarboxylic acid-based polyamide. The furandicarboxylic acid-based polyamide is derived from repeating units containing (A) 2,5-furandicarboxylic acid, (B) 1,4-cyclohexanedicarboxylic acid, and (C) 1,5-pentylenediamine, and (A) accounts for 10 to 45 mol% of the diacid units in terms of the total mol% of the diacid units. The use of bio-based 2,5-furandicarboxylic acid, which has the advantages of a melting point of 291 to 335°C and low water absorption (lower water absorption rate than polyamides with the same amide bond density), improves environmental protection. On the other hand, cyclohexane has a higher rigidity than aromatic rings and can form more hard carbon layers when burned. Furthermore, the furandicarboxylic acid-based polyamide has a high amide bond density and can achieve excellent synergistic effects when used in combination with a flame retardant, and the synergistic effects of the two provide excellent flame retardant effects.

Description

[Technical field]

[0001] The present invention relates to the technical field of polymeric materials, and in particular to furandicarboxylic acid-based polyamides and furandicarboxylic acid-based polyamide compositions. [Background technology]

[0002] Traditional polyamide monomers are mainly derived from petroleum, and currently face problems such as excessive consumption of petroleum resources, rapid increase in carbon dioxide emissions, and worsening greenhouse effect. Reducing the use of petroleum-based monomers can suppress carbon dioxide emissions, prevent greenhouse effect, solve the problems of environmental pollution and resource constraints, and build a sustainable society. Bio-based high-temperature resistant polyamide mainly refers to polyamides obtained by polymerization of bio-based aliphatic diamines or bio-based aromatic diacids. Bio-based monomers are usually extracted from animals and plants, which can realize green and sustainable development, while diversifying high-temperature resistant polyamide products to meet the needs of more fragmented industries.

[0003] After market research and analysis, it is believed that the bio-based monomers decanediamine, pentylenediamine, and furandicarboxylic acid are the bio-based high-temperature resistant polyamide monomer materials most likely to achieve substantial progress. Decanediamine is derived from castor oil and has already been mass-produced in China, but its selling price is high and its market competitiveness is weak. Pentylenediamine is obtained by fermenting glutamic acid and has been mass-produced in China, with a low price and good market competitiveness. Furandicarboxylic acid is the only bio-based aromatic ring diacid monomer currently known and most likely to be industrialized in the near future. Currently, research on furandicarboxylic acid is in the trial research and development stage both at home and abroad in China.

[0004] Chinese patent application CN106536187A discloses a furan-based polyamide using bio-based monomer 2,5-furandicarboxylic acid, in which the diamine is an aliphatic diamine, an aromatic diamine, etc., and has the advantage of good gas barrier properties. However, the gas barrier properties are mainly achieved by polymerizing short carbon chain diamines (1,3-propanediamine, ) to increase the amide bond density. However, this furan polyamide has poor flame retardancy. Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a furandicarboxylic acid-based polyamide having the advantages of excellent flame retardancy, a high melting point, being bio-based and therefore environmentally friendly, and having a low water absorption rate.

[0006] Another object of the present invention is to provide a composition containing the above-mentioned furandicarboxylic acid-based polyamide. [Means for solving the problem]

[0007] The present invention is achieved by the following technical solutions:

[0008] The furandicarboxylic acid-based polyamide is derived from repeating units containing (A) 2,5-furandicarboxylic acid, (B) 1,4-cyclohexanedicarboxylic acid, and (C) 1,5-pentylenediamine, in which, in terms of the total molar percentage of the diacid units, (A) accounts for 10 to 45 mol % of the diacid units.

[0009] Preferably, (A) accounts for 10 to 30 mol % of the diacid units, based on the total mol % of the diacid units.

[0010] More preferably, (A) accounts for 10 to 15 mol % of the diacid units, based on the total mol % of the diacid units.

[0011] More preferably, the content of (A) in the diacid units is such that the melting point and water absorption are higher.

[0012] The furandicarboxylic acid polyamide has a relative viscosity of 1.8 to 2.4.

[0013] The melting point of the furandicarboxylic acid polyamide is 291 to 335°C.

[0014] The furandicarboxylic acid polyamide has a water absorption rate of 3.3% or less.

[0015] Add the reactant materials (diamine, diacid) in a specified ratio to a pressure cooker equipped with a magnetic coupling stirrer, a condenser tube, a gas phase port, a feed port, and a pressure-resistant explosion-proof port, then add benzoic acid, sodium hypophosphite (catalyst), and deionized water so that the amount of benzoic acid material is 2-3% of the total weight of diamine and diacid, the weight of sodium hypophosphite is 0.05-0.15% of the weight of other input materials other than deionized water, and the weight of deionized water is 25-35% of the total weight of the input materials, suction by vacuum, introduce protective gas as high-purity nitrogen, and stir for 2 hours. The temperature is raised to 210-230°C, the reaction mixture is stirred at 210-230°C for 0.5-2 hours, then the temperature of the reactant is raised to 220-240°C while stirring, and the reaction is continued at a constant temperature of 220-240°C and a constant pressure of 2.1-2.3MPa for 1-3 hours, the formed water is removed to keep the pressure constant, after the reaction is completed, the material is discharged, and the prepolymer is vacuum dried at 70-90°C to obtain a prepolymerization product, and the prepolymerization product is thickened in solid phase for 8-12 hours under the conditions of 240-260°C and vacuum of 40-60Pa to obtain a furandicarboxylic acid-based polyamide.

[0016] A furandicarboxylic acid-based polyamide composition comprising the following components: 40 to 70 parts by weight of the furandicarboxylic acid-based polyamide; 10 to 30 parts by weight of a halogen-free flame retardant; and 0 to 50 parts by weight of a reinforcing material.

[0017] The non-halogen flame retardant is at least one selected from phosphine-based flame retardants, phosphinate-based flame retardants, hypophosphonite-based flame retardants, phosphonite-based flame retardants, phosphite-based flame retardants, phosphine oxide-based flame retardants, phosphinate-based flame retardants, hypophosphite-based flame retardants, phosphonate-based flame retardants, phosphonate-based flame retardants, phosphate-based flame retardants, and polyphosphate-based flame retardants.

[0018] The hypophosphite-based flame retardant is at least one selected from aluminum hypophosphite, calcium hypophosphite, dimethyl aluminum hypophosphite, diethyl aluminum hypophosphite, and methyl ethyl aluminum hypophosphite, the phosphate-based flame retardant is at least one selected from bisphenol A bis(diphenyl phosphate), phenoxyphosphazene, resorcinol (diphenyl phosphate), triphenyl phosphate, melamine polyphosphate, and melamine cyanurate, and the polyphosphate-based flame retardant is at least one selected from ammonium polyphosphate, melamine phosphate, melamine pyrophosphate, and melamine cyanurate.

[0019] The reinforcing material is at least one selected from a fibrous filler and a non-fibrous filler, the fibrous filler is at least one selected from a glass fiber, a carbon fiber, a basalt fiber, a bamboo fiber, a hemp fiber, a cellulose fiber, or an aramid fiber, and the non-fibrous filler is at least one selected from alumina, carbon black, clay, zirconium phosphate, kaolin, calcium carbonate, copper powder, diatomaceous earth, graphite, mica, silica stone, titanium dioxide, zeolite, talc, wollastonite, glass beads, or glass powder.

[0020] The polyamide molding composition of the present invention can be used to manufacture various electronic connector devices that require SMT (surface mount technology), such as USB, TYPE-C, and DDR, and is widely used in the fields of electronics, electricity, automobiles, etc. Effect of the Invention

[0021] Compared with the prior art, the present invention has the following beneficial effects: 1. In the furandicarboxylic acid-based polyamide of the present invention, both diacid units contain rigid rings, and the rigidity of cyclohexane is higher than that of aromatic rings, so that a larger amount of hard carbon layer can be formed upon combustion. Furthermore, the polyamide resin of the present invention has a high amide bond density and exerts an excellent synergistic effect when used in combination with a flame retardant, resulting in good flame retardancy. 2. In the present invention, by adjusting the ratio of furandicarboxylic acid to cyclohexanedicarboxylic acid, it is possible to produce a furandicarboxylic acid-based polyamide having a melting point in the range of 291 to 335°C and excellent heat resistance and processability. 3. Although the furandicarboxylic acid-based polyamide of the present invention has a high amide bond density (compared to PA10T, PA1010, PA6T, PA56, etc.), both the furandicarboxylic acid and the cyclohexanedicarboxylic acid monomer have rigid rings, and the rigidity of cyclohexane is higher than that of aromatic rings, so that the water absorption rate is 3.3% or less. The polyamide of the present invention has a high rigidity of the molecular chain, and the rigid regions formed by these rigid molecular chains inhibit the diffusion of water molecules in the polyamide resin, so that the water absorption rate is low and the dimensional stability is excellent. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The present invention will be described in detail below with reference to specific examples. The following examples are provided to facilitate a person skilled in the art to further understand the present invention, but are not intended to limit the present invention in any manner. However, those skilled in the art may make some modifications and improvements without departing from the concept of the present invention. All of these fall within the scope of protection of the present invention.

[0023] The origins of the raw materials used in the present invention are as follows: 2,5-Furandicarboxylic acid: 98% purity, purchased from Ningbo Institute of Materials, Chinese Academy of Sciences 1,4-Cyclohexanedicarboxylic acid: 98% purity, purchased from Sigma-Aldrich 1,6-Adipic acid: 98% purity, purchased from Sigma-Aldrich Terephthalic acid: 98% purity, purchased from Sigma-Aldrich 1,5-Pentylenediamine: 98% purity, purchased from Shanghai Kaisai Chemical Co., Ltd. 1,6-Hexamethylenediamine: 98% purity, purchased from Sigma-Aldrich 1,10-Decanediamine: 98% purity, purchased from Wuxi Indanelong Co., Ltd. Benzoic acid: analytically pure, purchased from Sigma-Aldrich Sodium hypophosphite: analytically pure, purchased from Sigma-Aldrich Halogen-free flame retardant A: aluminum diethylphosphinate, OP1230, phosphorus content 23-24% by mass, purchased from Clariant Halogen-free flame retardant B: Melamine cyanurate, MELAPUR200-70, nitrogen 42-44% by mass, phosphorus content 12-14% by mass, purchased from BASF Reinforcement: Glass fiber, ECS11-4 .5-560A, average diameter 11 microns, purchased from China Megalith.

[0024] The polyamide resins of the examples and comparative examples are obtained by the same method as follows: The reaction raw materials (diamine, diacid) are added to a pressure cooker equipped with a magnetic coupling stirrer, a condenser tube, a gas phase port, a feed port, and a pressure-resistant explosion-proof port in the proportions shown in the table, and then benzoic acid, sodium hypophosphite (catalyst), and deionized water are added so that the amount of benzoic acid material is 2% of the total weight of diamine and diacid, the weight of sodium hypophosphite is 0.08% of the weight of other input raw materials other than deionized water, and the weight of deionized water is 25% of the total weight of the input raw materials, and then vacuum suction is performed, protective gas as high-purity nitrogen is introduced, and the mixture is stirred for 2 hours. The temperature is raised to 30°C, the reaction mixture is stirred at 220°C for 0.5-2 hours, then the temperature of the reactants is raised to 240°C while stirring, the reaction is continued at a constant temperature of 240°C and a constant pressure of 2.3MPa for 1-3 hours, the formed water is removed to keep the pressure constant, after the reaction is completed, the material is discharged, the prepolymer is vacuum dried at 70-90°C to obtain a prepolymerization product, and the prepolymerization product is thickened in solid phase for 8-12 hours under vacuum conditions of 260°C and 50 Pa to obtain a furandicarboxylic acid-based polyamide (a polyamide not containing furandicarboxylic acid). Test Method:

[0025] (1) Test method for relative viscosity of polyamide resin: For the measurement method of viscosity of polyamide, refer to GB12006.1-89. Specific test method: Measure the relative viscosity ηr of polyamide with a concentration of 0.25g / dl in 98% concentrated sulfuric acid at 25±0.01℃.

[0026] (2) Polyamide melting point test method: Refer to ASTM D3418-2003, Standard Test Method for Transition Temperatures of Polymers By Differential Scanning Calorimetry. Specific test method: Test the melting point of the sample using a Perkin Elmer Dimond DSC analyzer. Nitrogen atmosphere, flow rate 50mL / min. In the test, the sample was first heated to 350°C at 20°C / min, kept at 350°C for 2 minutes to remove the thermal history of the resin, then cooled to 50°C at 20°C / min, kept at 50°C for 2 minutes, and further heated to 350°C at 20°C / min. The endothermic peak temperature at this time was taken as the melting point Tm.

[0027] (3) Water absorption rate of polyamide: A sample is injection molded into a 20mm x 20mm x 2mm sample, and its weight is a0. After placing it in 95℃ water for 240 hours, its weight is a1. Here, water absorption rate = (a1-a0) / a0*100%.

[0028] (4) Flame retardancy: Referring to the UL94 V-0 test standard, the dimensions of the standard rod-shaped test specimen are 125±5mm in length, 13.0±0.5mm in width, and 0.8mm in thickness. Five test specimens are treated at 23±2℃ and 50±5% for a minimum of 48 hours. The Bunsen burner flame is aligned with the center of the lower end of the test specimen, and the distance between the center of the top surface of the Bunsen burner tube and the lower end surface of the test specimen is kept at 10±1mm, and this distance is maintained for 10±0.5S. If necessary, the Bunsen burner can be moved according to the change in the length position of the test specimen. Immediately after applying the flame to the test specimen for 10±0.5S, the Bunsen burner is withdrawn at a speed of about 300mm / s to a position at least 150mm away from the test specimen. At the same time, the flaming burning time T1 (unit: s) of the test specimen is measured using a timing device. After the flaming combustion of the test specimen has ceased, even if the Bunsen burner has not been moved 150 mm away from the test specimen, immediately maintain the distance from the mouth of the Bunsen burner to the bottom surface of the test specimen at 10±1 mm, and apply the flame again for 10±0.5 s, and when necessary, remove the Bunsen burner and remove the drippings, and immediately move the Bunsen burner at least 150 mm away from the test specimen after applying the flame, and at the same time start the timer to measure the flaming time T2 and the flameless burning time T3 of the test specimen, and record T2 and T3. If all five splines are T1+T2+T3<10s and the drippings do not ignite the cotton underneath, it is considered to meet the V-0 conditions.

[0029] [Table 1]

[0030] As can be seen from Examples 1 to 6, the higher the content of 1,4-cyclohexanedicarboxylic acid, the higher the melting point and the lower the water absorption rate.

[0031] [Table 2]

[0032] The furandicarboxylic acid-based polyamide resin of Comparative Example 1 has no practical value because its melting point exceeds its decomposition temperature.

[0033] As can be seen from Comparative Example 2, the higher the content of 2,5-furandicarboxylic acid, the higher the water absorption rate, the lower the melting point, and the lower the utility value.

[0034] As can be seen from Comparative Example 3, when 2,5-furandicarboxylic acid is changed to terephthalic acid, the water absorption rate does not become 3.3% or less.

[0035] As can be seen from Comparative Example 5, when cyclohexanedioic acid is changed to adipic acid, the water absorption rate increases even though the amide bond density decreases.

[0036] As can be seen from Comparative Example 6, even when cyclohexanedioic acid is replaced with terephthalic acid having a similar structure, the water absorption rate is high and the melting point is low.

[0037] As can be seen from Comparative Example 7, when 1,5-pentylenediamine is changed to 1,6-hexamethylenediamine, the melting point decreases.

[0038] [Table 3]

[0039] As can be seen from Examples 7 to 12, the furandicarboxylic acid-based polyamide composition of the present invention has good flame retardancy.

[0040] [Table 4]

[0041] As can be seen from Comparative Examples 8 and 9, when the melting point is too high or too low, modification and processing / molding cannot be performed.

[0042] As can be seen from Comparative Examples 10 to 14, the flame retardancy is poor in other diacid / diamine schemes.

Claims

Claim 1 A furandicarboxylic acid-based polyamide, which is derived from repeating units containing (A) 2,5-furandicarboxylic acid, (B) 1,4-cyclohexanedicarboxylic acid, and (C) 1,5-pentylenediamine, and in terms of the total molar percentage of diacid units, (A) accounts for 10 to 45 mol% of the diacid units. Claim 2 The furandicarboxylic acid-based polyamide according to claim 1, wherein in terms of the total molar percentage of diacid units, (A) accounts for 10 to 30 mol% of the diacid units. Claim 3 The furandicarboxylic acid-based polyamide according to claim 2, wherein in terms of the total molar percentage of diacid units, (A) accounts for 10 to 15 mol% of the diacid units. Claim 4 The furandicarboxylic acid-based polyamide according to claim 1, wherein the relative viscosity of the furandicarboxylic acid-based polyamide is 1.8 to 2.

4. Claim 5 The furandicarboxylic acid-based polyamide according to claim 1, wherein the melting point of the furandicarboxylic acid-based polyamide is 291 to 335 °C. Claim 6 The furandicarboxylic acid-based polyamide according to claim 1, wherein the water absorption rate of the furandicarboxylic acid-based polyamide is 3.3% or less. Claim 7 A method for producing a furandicarboxylic acid-based polyamide according to any one of claims 1 to 6, comprising the steps of adding reaction raw materials to an autoclave at a predetermined ratio, and then adding benzoic acid, sodium hypophosphite, and deionized water such that the amount of substance of benzoic acid is 2 to 3% of the total weight of diamine and diacid, the weight of sodium hypophosphite is 0.05 to 0.15% of the weight of other input raw materials except deionized water, and the weight of deionized water is 25 to 35% of the total weight of input raw materials; performing vacuum suction, introducing a protective gas as high-purity nitrogen, heating to 210 to 230 °C within 2 hours while stirring, and stirring the reaction mixture at 210 to 230 °C for 0.5 to 2 hours; then, while stirring, raising the temperature of the reaction product to 220 to 240 °C, maintaining the reaction at a constant temperature of 220 to 240 °C and a constant pressure of 2.1 to 2.3 MPa for 1 to 3 hours, removing the formed water and maintaining the pressure constant, discharging the material after the reaction is completed, vacuum drying the prepolymer at 70 to 90 °C to obtain a prepolymerization product, and thickening the prepolymerization product in a solid phase for 8 to 12 hours under vacuum conditions of 240 to 260 °C and 40 to 60 Pa to obtain a furandicarboxylic acid-based polyamide. **Claim 8**: A phthalic acid-based polyamide composition, comprising, as components, at least 50 parts by weight of the phthalic acid-based polyamide according to any one of Claims 1 to 6, 10 to 30 parts by weight of a non-halogen flame retardant, and 0 to 50 parts by weight of a reinforcing material, based on 100 parts by weight of the phthalic acid-based polyamide composition. A phthalic acid-based polyamide composition characterized by the above. **Claim 9** The non-halogen flame retardant is at least one selected from the group consisting of phosphine-based flame retardants, phosphinate-based flame retardants, hypophosphite-based flame retardants, phosphonite-based flame retardants, phosphite-based flame retardants, phosphonate-based flame retardants, phosphite-based flame retardants, phosphine oxide-based flame retardants, phosphinate-based flame retardants, hypophosphite-based flame retardants, phosphonate-based flame retardants, phosphate-based flame retardants, polyphosphate-based flame retardants, or phosphinate-based flame retardants. The hypophosphite-based flame retardant is at least one selected from the group consisting of aluminum hypophosphite or calcium hypophosphite. The phosphinate-based flame retardant is at least one selected from the group consisting of aluminum dimethylphosphinate, aluminum diethylphosphinate, or aluminum methyl ethylphosphinate. The phosphate-based flame retardant is at least one selected from the group consisting of bisphenol A bis(diphenyl phosphate), resorcinol (diphenyl phosphate), triphenyl phosphate, or melamine phosphate. The polyphosphate-based flame retardant is at least one selected from the group consisting of ammonium polyphosphate, melamine polyphosphate, melamine pyrophosphate, or melamine polyphosphate. A phthalic acid-based polyamide composition according to Claim 8, characterized by the above. **Claim 10** The reinforcing material is at least one selected from fibrous fillers and non-fibrous fillers, the fibrous filler is at least one selected from glass fiber, carbon fiber, basalt fiber, bamboo fiber, hemp fiber, cellulose fiber, or aramid fiber, and the non-fibrous filler is at least one selected from alumina, carbon black, clay, zirconium phosphate, kaolin, calcium carbonate, copper powder, diatomaceous earth, graphite, mica, silica, titanium dioxide, zeolite, talc, wollastonite, glass beads, or glass powder. The flaky carboxylic acid-based polyamide composition according to claim 8, characterized by this.