Polyamide resin and polyamide composition

Abstract

The present invention relates to a polyamide resin and a polyamide composition, the polyamide resin comprising the following components: a unit derived from a diamine monomer and a dicarboxylic acid monomer; based on the molar weight of all diamine monomers, 0-100 mol% of 1, 6-hexamethylenediamine is excluded from 0 mol% and 100 mol% of 1, 6-hexamethylenediamine; based on the molar weight of all diamine monomers, 0.01 to 5 mol% of 1, 2-cyclohexanediamine; the content of the trans isomer of the 1, 2-cyclohexanediamine is not less than 70% of the total molar weight of the 1, 2-cyclohexanediamine. Compared with the prior art, the prepared polyamide resin has the advantages that the fluidity is improved, and the heat resistance is improved.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology and relates to a polyamide resin and a polyamide composition. Background Technology

[0002] Polyamides, represented by polyamide 6 (PA6) and polyamide 66 (PA66), are one of my country's five major engineering plastics. They possess excellent mechanical properties, good impact resistance, low coefficient of friction, wear resistance, self-lubrication, and shock absorption, making them widely used in textiles, automobiles, machinery manufacturing, and electronics. With the advancements in surface mount technology (SMT) in recent years, the heat resistance requirements for polyamide materials are increasing in the electronics industry, where reflow soldering heat resistance is crucial, and in the increasingly demanding heat resistance requirements of fuel-powered vehicle engines. Furthermore, in many polyamide application areas, especially in the electronics industry, there is a growing trend towards miniaturization and micro-miniaturization of molded parts, which places even higher demands on the flowability of polyamides.

[0003] Alicyclic compounds, especially those with significant steric hindrance, are used as monomers in the polymerization of copolyamides, primarily to reduce the crystallinity and crystal size of the polyamide and increase the content of amorphous forms. They are one of the important monomers for preparing transparent polyamide materials. For example, CN102076770A discloses a partially crystalline transparent polyamide containing 10-40 mol% bis(4-amino-3-methylcyclohexyl)methane and / or bis(4-amino-cyclohexyl)methane based on the total diamine content. However, the introduction of alicyclic monomers, while increasing the glass transition temperature of the copolyamide, often leads to a decrease in crystallinity and melting temperature. The reduced heat resistance of the material limits its application under high-temperature conditions, especially high-temperature environments.

[0004] For example, CN104619777A discloses a copolyamide containing more than 25 mol% of 1,4-cyclohexanedicarboxylic acid in its total copolyamide content. This copolyamide exhibits sufficient crystallization under mold molding at 80°C and possesses mold contamination optimization characteristics. However, as can be seen from the description of the relative crystallinity used in the examples, the material shows a cold crystallization peak during the first temperature rise in the differential scanning calorimetry (DSC) test. A cold crystallization peak often indicates incomplete crystallization of the material, suggesting that the introduction of alicyclic dicarboxylic acid leads to a significant decrease in the degree of crystallinity.

[0005] For example, CN112341618A discloses a copolyamide containing hexamethylenediamine and 1,3-bis(aminomethyl)cyclohexane, wherein the 1,3-bis(aminomethyl)cyclohexane group accounts for 12.5-22 mol% of the total copolyamide content. This copolyamide exhibits an improved high-gloss surface after molding. However, the introduction of alicyclic monomers significantly reduces the melting and crystallization temperatures, especially the melting temperature, which decreases by 30-50°C. This is clearly detrimental to the heat resistance of the polyamide.

[0006] The decrease in crystallinity and melting temperature of copolyamides caused by alicyclic monomers can be balanced by adjusting the content of other monomers. For example, CN105308096A discloses a PA6T / 6I copolyamide with a total copolyamide content of 7.5-12.5 mol% isophorone diamine. The introduction of isophorone diamine increases the glass transition temperature of the material, but significantly reduces crystallinity and melting temperature. This patent offsets the decrease in crystallinity and melting temperature by increasing the proportion of terephthalic acid in the diacid component of the raw material, thereby obtaining a semi-aromatic copolyamide with improved properties. This patent does not disclose the flowability of the copolyamide. Since the cyclohexane in the isophorone diamine chemical structure has up to four non-reactive methyl / methylene groups, it will cause significant resistance during molecular chain movement, suggesting that isophorone diamine will lead to a decrease in material flowability. Summary of the Invention

[0007] The purpose of this invention is to overcome at least one of the defects of the prior art and provide a polyamide resin and a polyamide composition. Compared with the prior art, the polyamide resin prepared by this invention has improved flowability and heat resistance.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] One of the technical solutions of the present invention is to provide a polyamide resin, which comprises the following components:

[0010] Units derived from diamine monomers and dicarboxylic acid monomers;

[0011] Based on the total molar amount of all diamine monomers, 0-100 mol%, excluding 0 mol% and 100 mol% of 1,6-hexanediamine;

[0012] Based on the total molar amount of all diamine monomers, 0.01-5 mol% of 1,2-cyclohexanediamine;

[0013] The content of the trans isomer of the 1,2-cyclohexanediamine is not less than 70% of the total molar amount of the 1,2-cyclohexanediamine.

[0014] As a preferred technical solution, the molar ratio of the sum of the 1,6-hexanediamine and the aliphatic diamine to the dicarboxylic acid monomer is 1:1.

[0015] Further, the diamine monomer is selected from 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,14-tetradecanediamine, 1,16-hexadecanediamine, 1,18-octadecanediamine, 1-butyl-1,2-ethylenediamine, 1,1-dimethyl-1,4-butanediamine, 1- Ethyl-1,4-butanediamine, 1,2-dimethyl-1,4-butanediamine, 1,3-dimethyl-1,4-butanediamine, 1,4-dimethyl-1,4-butanediamine, 2,3-dimethyl-1,4-butanediamine, 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 2,5-dimethyl-1,6-hexanediamine, 2,4-dimethyl-1,6-hexanediamine, 3,3-dimethyl-1,6-hexanediamine, 2,2-dimethyl 1,6-Hexanediamine, 2,2,4-Trimethyl-1,6-Hexanediamine, 2,4,4-Trimethyl-1,6-Hexanediamine, 2,4-Diethyl-1,6-Hexanediamine, 2,2-Dimethyl-1,7-Heptanediamine, 2,3-Dimethyl-1,7-Heptanediamine, 2,4-Dimethyl-1,7-Heptanediamine, 2,5-Dimethyl-1,7-Heptanediamine, 2-Methyl-1,8-Octadiamine, 3-Methyl-1,8-Octadiamine, 4-Methyl- One or more of the following: 1,8-octanediamine, 1,3-dimethyl-1,8-octanediamine, 1,4-dimethyl-1,8-octanediamine, 2,4-dimethyl-1,8-octanediamine, 3,4-dimethyl-1,8-octanediamine, 4,5-dimethyl-1,8-octanediamine, 2,2-dimethyl-1,8-octanediamine, 3,3-dimethyl-1,8-octanediamine, 4,4-dimethyl-1,8-octanediamine, and 5-methyl-1,9-nonanediamine.

[0016] Furthermore, the dicarboxylic acid monomer is selected from one or more of aromatic diacids and aliphatic diacids.

[0017] Furthermore, the aromatic diacid is selected from one or more of terephthalic acid, isophthalic acid, and naphthalic acid.

[0018] Further, the aliphatic diacid is selected from one or more of oxalic acid, malonic acid, 1,4-succinic acid, 1,5-glutaric acid, 1,6-adipic acid, 1,7-heptanedic acid, 1,8-octanoic acid, 2-methyloctanoic acid, 1,9-azelaic acid, 1,10-sebacic acid, 1,11-undecanoic acid, 1,12-dodecanoic acid, 1,13-tridecanoic acid, 1,14-tetradecanoic acid, and cyclohexanedicarboxylic acid.

[0019] Furthermore, by differential scanning calorimetry (DSC) according to ISO 11357-1 / 3 standard, at a heating and cooling rate of 20 °C / min, the polyamide resin was found to have a crystallization enthalpy of at least 20 J / g.

[0020] Furthermore, the relative viscosity of the polyamide resin obtained when measuring a polyamide solution with a concentration of 10 mg / mL in concentrated sulfuric acid at a temperature of 25°C and a concentration of 98% is greater than 1.80.

[0021] As a preferred technical solution, the amino content of the polyamide resin, as determined by a fully automatic potentiometric titrator, is 30-150 mol / t.

[0022] As a preferred technical solution, the carboxyl content of the polyamide resin, as determined by a fully automatic potentiometric titrator, is 50-300 mol / t.

[0023] Furthermore, based on the total molar amount of all diamine monomers, 0.5-3 mol% of 1,2-cyclohexanediamine is considered a more preferred technical solution.

[0024] Furthermore, the content of the trans isomer of the 1,2-cyclohexanediamine is not less than 80% of the total molar amount of the 1,2-cyclohexanediamine, which is a more preferred technical solution.

[0025] As a preferred technical solution, the trans isomer of 1,2-cyclohexanediamine contains 80-100% of the total molar amount of 1,2-cyclohexanediamine.

[0026] One of the technical solutions of the present invention is to provide a method for preparing the polyamide resin, the method comprising the following steps:

[0027] Raw material monomers, water, catalysts, and capping agents are added. The raw material monomers include diamine monomers and dicarboxylic acid monomers. A pre-reaction is carried out to obtain a prepolymer. A thickening reaction is carried out under vacuum conditions to finally obtain polyamide resin.

[0028] As a preferred technical solution, the amount of water added is 40-60% of the total mass of the raw material monomers.

[0029] As a preferred technical solution, the catalyst is a phosphorus-containing inorganic acid salt.

[0030] As a preferred technical solution, the catalyst is sodium hypophosphite.

[0031] As a preferred technical solution, the amount of catalyst added is 0.1-0.5% of the total mass of the raw material monomers.

[0032] As a preferred technical solution, the capping agent is an amine or acid with a monoamine or monocarboxyl functional group.

[0033] As a preferred technical solution, the capping agent is stearic acid.

[0034] As a preferred technical solution, the amount of the capping agent added is 0.5-4% of the total amount of dicarboxylic acid monomer.

[0035] As a preferred technical solution, the pre-reaction temperature is 180-200℃ and the time is 1-3h.

[0036] As a preferred technical solution, the temperature of the prepolymerization reaction is 230-250℃, the pressure is 2.2-3MPa, and the time is 2-4h.

[0037] As a preferred technical solution, the temperature of the thickening reaction is 230-260℃, the vacuum degree is 100-1000Pa, and the time is 10-20h.

[0038] One of the technical solutions of the present invention is to provide a polyamide composition comprising the aforementioned polyamide resin, wherein the polyamide composition comprises the following components:

[0039] 30-95 wt% polyamide resin, 0-70 wt% glass fiber and 0-50 wt% additives, wherein the sum of the mass percentages of polyamide resin, glass fiber and additives is 100%.

[0040] As a preferred technical solution, a glass fiber reinforced polyamide composition is prepared using a twin-screw extruder as a molding composition.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) By introducing 1,2-cyclohexanediamine during the polyamide polymerization stage, the present invention obtains a polyamide resin with significantly improved flowability. When a specific amount of 1,2-cyclohexanediamine is introduced, especially when a specific proportion of trans-1,2-cyclohexanediamine is reached, the melt viscosity of the polyamide resin is significantly reduced, demonstrating better flowability during processing.

[0043] (2) By introducing 1,2-cyclohexanediamine, which is added in less amount than in the prior art, especially 1,2-cyclohexanediamine with a high content of trans isomer, into the polymerization stage of polyamide, the glass transition temperature of polyamide is significantly increased without having much impact on the crystallization of the material, thereby improving the heat resistance of the material. Detailed Implementation

[0044] The present invention will now be described in detail with reference to specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0045] Unless otherwise specified, the equipment used in the following embodiments is conventional equipment in the art; unless otherwise specified, the reagents used are commercially available products or prepared by conventional methods in the art. In the following embodiments, unless otherwise described in detail, conventional experimental methods in the art can be used.

[0046] Polyamide (PA) should be understood as an inclusive term encompassing both homopolymers and copolymers. The selected symbols and abbreviations for polyamides and their monomers correspond to those listed in ISO standard 16396-1 (2015, (D)) and are synonymous with the IUPAC names of the monomers, such as 1,2-cyclohexanediamine (also known as 1,2-diaminocyclohexane, CAS No. 694-83-7, DCH), 1,6-hexanediamine (CAS No. 124-09-4), 1,6-adipic acid (CAS No. 124-04-9), terephthalic acid (CAS No. 100-21-0, T), and isophthalic acid (CAS No. 121-95-5, I).

[0047] Example 1:

[0048] A polyamide resin and its preparation method, the specific steps of which are as follows:

[0049] In a high-pressure reactor equipped with a stirrer and a condenser, 10 mol of 1,6-hexanediamine, 0.002 mol of 1,2-cyclohexanediamine, 5.5 mol of terephthalic acid, 4.5 mol of 1,6-adipic acid, deionized water, sodium hypophosphite, and stearic acid were added. The trans isomer of 1,2-cyclohexanediamine accounted for 85% of the total molar amount of 1,2-cyclohexanediamine. The amount of deionized water added was 50% of the total mass of the raw material monomers, the amount of sodium hypophosphite added was 0.3% of the total mass of the raw material monomers, and the amount of stearic acid added was 2% of the total molar amount of the dicarboxylic acid monomers. The reactor was evacuated and purged with nitrogen. The temperature was then raised to 19°C for pre-reaction. The mixture was stirred at 0℃ for 2 hours, then heated to 240℃ and held at that temperature for 3 hours, while maintaining a pressure of 2.6 MPa. After the prepolymerization reaction was completed, the valve was opened to discharge the water and materials from the reactor in the form of flash evaporation, resulting in a prepolymer. After drying, the prepolymer was added to a solid-phase thickening device for thickening reaction. The temperature was gradually increased to 245℃ and maintained at that temperature for 15 hours. Byproducts were discharged by vacuuming, with the vacuum degree maintained at 500 Pa. After the reaction was completed, the temperature was lowered and the material was removed, finally yielding polyamide resin.

[0050] Example 2:

[0051] A polyamide resin and its preparation method are basically the same as in Example 1, except that 10 mol of 1,6-hexanediamine, 0.01 mol of 1,2-cyclohexanediamine, 5.6 mol of terephthalic acid, 4.4 mol of 1,6-adipic acid, deionized water, sodium hypophosphite, and stearic acid are added.

[0052] Example 3:

[0053] A polyamide resin and its preparation method are basically the same as in Example 1, except that 10 mol of 1,6-hexanediamine, 0.1 mol of 1,2-cyclohexanediamine, 5.8 mol of terephthalic acid, 4.2 mol of 1,6-adipic acid, deionized water, sodium hypophosphite, and stearic acid are added.

[0054] Example 4:

[0055] A polyamide resin and its preparation method are basically the same as in Example 1, except that 10 mol of 1,6-hexanediamine, 0.3 mol of 1,2-cyclohexanediamine, 5.9 mol of terephthalic acid, 4.1 mol of 1,6-adipic acid, deionized water, sodium hypophosphite, and stearic acid are added.

[0056] Example 5:

[0057] A polyamide resin and its preparation method are basically the same as in Example 1, except that 10 mol of 1,6-hexanediamine, 0.46 mol of 1,2-cyclohexanediamine, 6 mol of terephthalic acid, 4 mol of 1,6-adipic acid, deionized water, sodium hypophosphite, and stearic acid are added.

[0058] Example 6:

[0059] A polyamide resin and its preparation method are basically the same as in Example 1, except that 1 mol of 1,6-hexanediamine, 9 mol of 1,10-decanediamine, 0.006 mol of 1,2-cyclohexanediamine, 9 mol of terephthalic acid, 1 mol of 1,6-adipic acid, deionized water, sodium hypophosphite, and stearic acid are added.

[0060] Example 7:

[0061] A polyamide resin and its preparation method are basically the same as in Example 1, except that 0.5 mol of 1,6-hexanediamine, 9.5 mol of 1,10-decanediamine, 0.2 mol of 1,2-cyclohexanediamine, 9.5 mol of terephthalic acid, 0.5 mol of 1,6-adipic acid, deionized water, sodium hypophosphite, and stearic acid are added.

[0062] Example 8:

[0063] A polyamide resin and its preparation method are basically the same as in Example 1, except that 5.5 mol of 1,6-hexanediamine, 4.5 mol of 1,10-decanediamine, 0.06 mol of 1,2-cyclohexanediamine, 10 mol of terephthalic acid, deionized water, sodium hypophosphite, and stearic acid are added.

[0064] Example 9:

[0065] A polyamide resin and its preparation method are basically the same as in Example 1, except that 6 mol of 1,6-hexanediamine, 4 mol of 1,10-decanediamine, 0.42 mol of 1,2-cyclohexanediamine, 10 mol of terephthalic acid, deionized water, sodium hypophosphite, and stearic acid are added.

[0066] Comparative Example 1:

[0067] A polyamide resin and its preparation method are basically the same as in Example 1, except that 10 mol of 1,6-hexanediamine, 5.5 mol of terephthalic acid, 4.5 mol of 1,6-adipic acid, deionized water, sodium hypophosphite and stearic acid are added.

[0068] Comparative Example 2:

[0069] A polyamide resin and its preparation method are basically the same as in Example 1, except that 10 mol of 1,6-hexanediamine, 0.65 mol of 1,2-cyclohexanediamine, 5.5 mol of terephthalic acid, 4.5 mol of 1,6-adipic acid, deionized water, sodium hypophosphite, and stearic acid are added, and the content of the trans isomer of 1,2-cyclohexanediamine is 85% of the total molar amount of 1,2-cyclohexanediamine.

[0070] Comparative Example 3:

[0071] A polyamide resin and its preparation method are basically the same as in Example 1, except that 10 mol of 1,6-hexanediamine, 0.01 mol of 1,2-cyclohexanediamine, 5.6 mol of terephthalic acid, 4.4 mol of 1,6-adipic acid, deionized water, sodium hypophosphite, and stearic acid are added, and the content of the trans isomer of 1,2-cyclohexanediamine is 40% of the total molar amount of 1,2-cyclohexanediamine.

[0072] Comparative Example 4:

[0073] A polyamide resin and its preparation method are basically the same as in Example 1, except that 10 mol of 1,6-hexanediamine, 0.25 mol of 1,2-cyclohexanediamine, 5.8 mol of terephthalic acid, 4.2 mol of 1,6-adipic acid, deionized water, sodium hypophosphite, and stearic acid are added, and the content of the trans isomer of 1,2-cyclohexanediamine is 60% of the total molar amount of 1,2-cyclohexanediamine.

[0074] Comparative Example 5:

[0075] A polyamide resin and its preparation method are basically the same as in Example 1, except that 10 mol of 1,10-decanediamine, 0.22 mol of 1,2-cyclohexanediamine, 10 mol of terephthalic acid, deionized water, sodium hypophosphite and stearic acid are added.

[0076] The performance of the above polyurethane resin was tested:

[0077] Semi-crystalline polyamides typically have a morphology that includes crystalline regions characterized by crystallization temperature (Tc), crystallization enthalpy (ΔHc), melting temperature (Tm), and melting enthalpy (ΔHm), as well as amorphous regions characterized by glass transition temperature (Tg).

[0078] The melting temperature was determined by differential scanning calorimetry (DSC) according to ISO 11357-1 / 3, using pre-dried polyamide resin in a nitrogen atmosphere, with a heating and cooling rate of 20 °C / min; the melting temperature was calculated from the peak value of the highest melting peak in the second heating cycle.

[0079] The polyamide resin of the present invention and its various preferred and specific embodiments have a melting temperature of at least 250°C, preferably 290-330°C;

[0080] The glass transition temperature was determined by differential scanning calorimetry according to ISO 11357-1 / 2, using pre-dried polyamide resin in a nitrogen atmosphere, with a heating and cooling rate of 20 °C / min. The glass transition temperature was calculated from the peak value of the first derivative (relative to time) of the thermal curve corresponding to the inflection point in the second heating cycle.

[0081] The glass transition temperature of the polyamide resin of the present invention and its various preferred and specific embodiments is at least 50°C, preferably at least 90°C;

[0082] The enthalpy of crystallization was determined by differential scanning calorimetry according to ISO 11357-1 / 3, using pre-dried polyamide resin in a nitrogen atmosphere, with a heating and cooling rate of 20 °C / min; the enthalpy of crystallization was calculated from the area under the crystallization peak during the cooling process of the second cycle.

[0083] The polyamide resin of the present invention and its various preferred and specific embodiments thereof have a crystallization enthalpy of at least 20 J / g;

[0084] Relative viscosity (η) r The test method for polyamide viscosity is based on the test method for polyamide in GB12006.1-89 standard. The specific method is to measure the relative viscosity of a polyamide solution with a concentration of 10 mg / mL in concentrated sulfuric acid at a temperature of 25 ± 0.01℃ and a concentration of 98%.

[0085] The polyamide resin of the present invention and various specific embodiments thereof have a relative viscosity greater than 1.80;

[0086] The amino content (M) was determined by titrating the amino content of polyamide resin using a fully automated potentiometric titrator. Specifically, 0.5 g of polyamide resin was added to a mixed solution of 45 mL phenol and 3 mL anhydrous methanol and heated under reflux until the polyamide resin was completely dissolved. After cooling to room temperature, the amino content was titrated with a hydrochloric acid solution of a standardized concentration.

[0087] The amino content of the polyamide resin of the present invention and its various specific embodiments is 30-150 mol / t;

[0088] The carboxyl content (N) was determined by titrating the carboxyl content of polyamide resin using a fully automated potentiometric titrator. The specific method was as follows: 0.5 g of polyamide resin was added to 50 mL of o-cresol and heated under reflux until the polyamide resin was completely dissolved. After cooling to room temperature, 400 μL of formaldehyde solution was added, and then the carboxyl content was titrated with a potassium hydroxide-ethanol solution of a standardized concentration.

[0089] The polyamide resin of the present invention and its various specific embodiments contain 50-300 mol / t of carboxyl groups;

[0090] Melt viscosity is used as an indicator of the flowability of polyamide resin in the molten state. Under the same test conditions, the lower the melt viscosity, the higher the flowability of the polyamide resin.

[0091] The melt viscosity was tested using a high-pressure capillary rheometer on pre-dried polyamide resin. Specifically, a die with an inner diameter of 1 mm and a length of 40 mm was used for measurement. The test temperature was 20°C higher than the melt temperature of the polyamide resin, and the shear rate was measured within the range of 0-5000 s⁻¹. -1 A shear rate of 1000 s was selected. -1 The corresponding shear viscosity is taken as the melt viscosity of the polyamide resin.

[0092] Table 1 shows a comparison of the composition and properties of the polyamide resins in the above embodiments.

[0093] Table 1 Comparison of the composition and properties of polyamide resins in the examples

[0094]

[0095] Table 2 shows the comparison of the composition and properties of the polyamide resins in the above comparative examples.

[0096] Table 2 Comparison of the composition and properties of polyamide resins in the comparative examples

[0097] Comparative Example 1 2 3 4 5 terephthalic acid mol 5.5 5.5 5.6 5.8 10 1,6-Adipic acid mol 4.5 4.5 4.4 4.2 - 1,6-Hexamethylenediamine mol 10 10 10 10 - 1,10-decanediamine mol - - - - 10 1,2-Cyclohexanediamine mol - 0.65 0.01 0.25 0.22 trans isomer molar percentage - 85 40 60 85 Melting temperature ℃ 306 292 302 297 312 Glass transition temperature (°C) 80 110 80 83 120 Enthalpy of crystallization (J / g) 25.1 8.7 16.5 22.6 36.6 relative viscosity 2.16 2.08 2.07 2.13 2.10 Amino content (mol / t) 47 86 77 60 89 Carboxyl content (mol / t) 86 160 134 98 135 Melt viscosity Pa·s 164 147 144 128 219

[0098] As shown in Tables 1 and 2, it can be seen that compared with the normally polymerized PA6T / 66 copolyamide (Comparative Example 1), the melt viscosity of the copolyamide with added 1,2-cyclohexanediamine (Examples 1 to 5) is significantly reduced; the glass transition temperature is significantly increased. With the increase of 1,2-cyclohexanediamine content, the glass transition temperature increases monotonically, and the melt viscosity shows a trend of first decreasing and then increasing. Within the preferred range of 1,2-cyclohexanediamine required by the present invention, a preferred balance between material flowability and heat resistance can be obtained.

[0099] Examples 6 and 7 are PA10T / 66 containing a small amount of 1,6-hexanediamine monomer. Their melt viscosity is significantly lower than that of PA10T (Comparative Example 5). On the one hand, the chain length of the 1,10-decanediamine unit in PA10T is longer than that of 1,6-hexanediamine, making it more difficult for the molecular chain to untangle during melt flow. On the other hand, it shows that the effect of 1,2-cyclohexanediamine in reducing melt viscosity is more significant in the 1,6-hexanediamine system, and has no significant effect on the system without 1,6-hexanediamine monomer.

[0100] Examples 8 and 9 are PA6T / 10T copolyamides. It can be seen that 1,2-cyclohexanediamine still has a significant effect on increasing the glass transition temperature and reducing the melt viscosity, which again shows that the effect of 1,2-cyclohexanediamine is more obvious in the system containing 1,6-hexanediamine.

[0101] In Comparative Example 2, the content of 1,2-cyclohexanediamine exceeded the scope of the claims of this invention. Although the glass transition temperature was increased, it did not have a significant effect on reducing the melt viscosity, indicating that the content of 1,2-cyclohexanediamine only has the effect of improving fluidity within a certain range.

[0102] In Comparative Examples 3 and 4, the proportion of trans-1,2-cyclohexanediamine was lower than that in the claims of this invention. On the one hand, the glass transition temperature was not increased; on the other hand, no significant change was observed in the melt viscosity. This may be because cis-1,2-cyclohexanediamine has less steric hindrance, which has little effect on increasing the steric hindrance of the polyamide molecular chain and has little effect on the glass transition temperature. Moreover, when the cyclohexane structure is on the same side of the molecular chain, it increases the difficulty of molecular chain movement and has an adverse effect on flowability.

[0103] In summary, when alicyclic diamines with a specific molar percentage of trans isomers were introduced into polyamide resins in the embodiments, the melt viscosity decreased to varying degrees, significantly improving the flowability of the polyamide resins; the glass transition temperature increased to varying degrees, while the crystallization enthalpy and melting temperature did not change significantly, significantly improving the heat resistance of the polyamide resins; when the molar percentage of trans isomers of alicyclic diamines in the comparative examples was low, or when alicyclic diamines were not introduced or the addition amount was too high, there was no significant effect on improving the flowability and heat resistance of the polyamide resins.

[0104] Examples 10 to 18 and Comparative Examples 6 to 10:

[0105] A polyamide composition is prepared by applying the polyamide resins of Examples 1 to 9 and Comparative Examples 1 to 5 to a molding composition, using standard compounding conditions for glass fiber reinforced thermoplastic polyamide compositions, and employing a twin-screw extruder. The polyamide composition comprises the following components:

[0106] 70 wt% polyamide resin and 30 wt% glass fiber.

[0107] The performance of the above polyurethane composition was tested:

[0108] Tensile strength was tested according to ISO 527-2 standard at room temperature and at a tensile rate of 10 mm / min.

[0109] The pendulum notched impact strength was tested according to ISO 180-1A standard at room temperature with notch type A.

[0110] The method for testing molding flowability involves drying the polyamide composition and adding it to an injection molding machine. The barrel temperature is 20°C higher than the melt temperature of the corresponding polyamide resin, and the mold temperature is 120°C. Under an injection pressure of 3 MPa and an injection rate of 50 mm / s, a long strip mold with a length of 200 mm, a width of 5 mm, and a thickness of 1 mm is used to fill and mold the polyamide composition. The length of the molded part is then measured. Because the thickness of the mold is extremely small, the flow of the molding composition within the mold is usually very difficult, and it is almost impossible to completely fill the entire mold. Therefore, the molding length can be used to characterize the melt flow length of the molding composition. The longer the molding length, the higher the flowability.

[0111] Table 3 shows a comparison of the performance of the polyamide compositions in the above embodiments.

[0112] Table 3 Comparison of the performance of polyamide compositions in the examples.

[0113] Composition Examples 10 11 12 13 14 15 16 17 18 Resin used in the examples 1 2 3 4 5 6 7 8 9 Tensile strength (MPa) 191 196 194 195 199 165 168 180 182 <![CDATA[Notch impact strength kJ / m 2 > 10.5 14 11.2 12.1 8.5 14.2 15.1 10.1 9.7 Molding length (cm) 11.5 12.8 14.4 14.2 12.6 10.8 11.2 10.1 11.9

[0114] The performance comparison of the polyamide compositions in the above comparative examples is shown in Table 4.

[0115] Table 4 Comparison of the performance of polyamide compositions in the comparative examples

[0116] Comparative Examples of Compositions 6 7 8 9 10 Comparative examples of resins used 1 2 3 4 5 Tensile strength (MPa) 190 186 188 175 180 <![CDATA[Notch impact strength kJ / m 2 > 12 11.4 12.2 13.5 13.7 Molding length (cm) 3.5 5.7 3.3 2.7 1.2

[0117] As shown in Tables 3 and 4, it can be seen that the flow length of the polyamide composition with added glass fiber in the mold during melt injection molding corresponds to the melt viscosity of the polyamide resin used (Tables 1 and 2). The lower the melt viscosity, the better its fluidity in the molten state and the longer its flow length in the mold; conversely, the higher the viscosity in the molten state, the shorter the length of the sample that can flow in the mold. Due to the narrow flow channel design of the mold, the flow of polymer melt in the mold is restricted. It is generally very difficult to form a molding length exceeding 10 cm in this mold. Therefore, the difference in material fluidity can be judged by comparing the length of the molded samples.

[0118] The molding length of Examples 10 to 14 is significantly improved compared with Comparative Example 6. Within the preferred range of the present invention, the molding length of Examples 12 and 13 is slightly longer than that of Examples 10, 11 and 14. This trend corresponds to the melt viscosity of the resin used.

[0119] The flow lengths of Examples 15 to 18 were significantly improved compared to Comparative Example 10, further demonstrating that 1,2-cyclohexanediamine has the effect of improving flowability in the hexamethylenediamine system; however, the difference in flow length between PA10T / 66 in Examples 15 and 16 and PA6T / 10T in Examples 17 and 18 was not significant (relative to the difference in resin melt viscosity), because glass fiber has an adverse effect on the flowability of the material. After adding glass fiber, the difference in melt viscosity between the resins was offset to some extent;

[0120] Furthermore, in comparative examples outside the scope of the claims of this invention, such as Comparative Examples 7 to 9, the samples had shorter flow lengths, which corresponded to the higher melt viscosity of the resins used. This indicates that within the scope claimed by this invention, a specific content of 1,2-cyclohexanediamine, especially a higher content of the trans isomer, significantly improves the flowability of polyamide materials.

[0121] In summary, when alicyclic diamines with a specific trans isomer molar ratio were introduced into polyamide resins in the examples, the molding length increased to varying degrees, significantly improving the flowability of the polyamide composition. However, when the trans isomer molar ratio of alicyclic diamines in the comparative examples was low, or when alicyclic diamines were not introduced or the addition amount was too high, there was no significant effect on improving the flowability of the polyamide composition.

[0122] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A polyamide resin, characterized in that, The polyamide resin comprises the following components: Units derived from diamine monomers and dicarboxylic acid monomers; Based on the total molar amount of all diamine monomers, 0-100 mol%, excluding 0 mol% and 100 mol% of 1,6-hexanediamine; Based on the total molar amount of all diamine monomers, 0.01-5 mol% of 1,2-cyclohexanediamine; The content of the trans isomer of the 1,2-cyclohexanediamine is not less than 70% of the total molar amount of the 1,2-cyclohexanediamine.

2. The polyamide resin according to claim 1, characterized in that, The diamine monomer is selected from 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,14-tetradecanediamine, 1,16-hexadecanediamine, 1,18-octadecanediamine, 1-butyl-1,2-ethylenediamine, 1,1-dimethyl-1,4-butanediamine, 1-ethyl- 1,4-Butanediamine, 1,2-Dimethyl-1,4-Butanediamine, 1,3-Dimethyl-1,4-Butanediamine, 1,4-Dimethyl-1,4-Butanediamine, 2,3-Dimethyl-1,4-Butanediamine, 2-Methyl-1,5-Pentanediamine, 3-Methyl-1,5-Pentanediamine, 2,5-Dimethyl-1,6-Hexanediamine, 2,4-Dimethyl-1,6-Hexanediamine, 3,3-Dimethyl-1,6-Hexanediamine, 2,2-Dimethyl-1 6-Hexanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 2,4-diethyl-1,6-hexanediamine, 2,2-dimethyl-1,7-heptanediamine, 2,3-dimethyl-1,7-heptanediamine, 2,4-dimethyl-1,7-heptanediamine, 2,5-dimethyl-1,7-heptanediamine, 2-methyl-1,8-octanediamine, 3-methyl-1,8-octanediamine, 4-methyl-1 One or more of the following: 8-octanediamine, 1,3-dimethyl-1,8-octanediamine, 1,4-dimethyl-1,8-octanediamine, 2,4-dimethyl-1,8-octanediamine, 3,4-dimethyl-1,8-octanediamine, 4,5-dimethyl-1,8-octanediamine, 2,2-dimethyl-1,8-octanediamine, 3,3-dimethyl-1,8-octanediamine, 4,4-dimethyl-1,8-octanediamine, and 5-methyl-1,9-nonanediamine.

3. The polyamide resin according to claim 1, characterized in that, The dicarboxylic acid monomer is selected from one or more aromatic diacids and aliphatic diacids.

4. The polyamide resin according to claim 3, characterized in that, The aromatic diacid is selected from one or more of terephthalic acid, isophthalic acid, and naphthalic acid.

5. A polyamide resin according to claim 3, characterized in that, The aliphatic diacid is selected from one or more of the following: oxalic acid, malonic acid, 1,4-succinic acid, 1,5-glutaric acid, 1,6-adipic acid, 1,7-heptanedic acid, 1,8-octanoic acid, 2-methyloctanoic acid, 1,9-azelaic acid, 1,10-sebacic acid, 1,11-undecanoic acid, 1,12-dodecanoic acid, 1,13-tetrazanoic acid, 1,14-tetradecanoic acid, and cyclohexanedicarboxylic acid.

6. The polyamide resin according to claim 1, characterized in that, The polyamide resin was tested by differential scanning calorimetry according to ISO 11357-1 / 3 at a heating and cooling rate of 20 °C / min, and it was found that the polyamide resin had a crystallization enthalpy of at least 20 J / g.

7. The polyamide resin according to claim 1, characterized in that, The relative viscosity of the polyamide resin was greater than 1.80 when measured in concentrated sulfuric acid at 25°C and a concentration of 98% with a polyamide solution of 10 mg / mL.

8. The polyamide resin according to claim 1, characterized in that, Based on the total molar amount of all diamine monomers, 0.5-3 mol% of 1,2-cyclohexanediamine.

9. A polyamide resin according to claim 1, characterized in that, The content of the trans isomer of 1,2-cyclohexanediamine is not less than 80% of the total molar amount of 1,2-cyclohexanediamine.

10. A polyamide composition, characterized in that, The polyamide composition comprises the polyamide resin as described in any one of claims 1 to 9, and the polyamide composition comprises the following components: 30-95 wt% polyamide resin, 0-70 wt% glass fiber and 0-50 wt% additives, wherein the sum of the mass percentages of polyamide resin, glass fiber and additives is 100%.

Images