Rapid prototyping nylon 66 resin composition and method of making same

Abstract

The application provides a rapid forming nylon 66 resin composition and a preparation method thereof. The rapid forming nylon 66 resin composition comprises the following components in parts by weight: 100 parts of nylon 66 resin, 5-20 parts of nucleating agent masterbatch; the nucleating agent masterbatch comprises a nylon base and a compounded nucleating agent, the compounded nucleating agent comprises benzoate and nano-SiO2; the mass percentage of the compounded nucleating agent is 5-20% in 100% of the mass percentage of the nucleating agent masterbatch. The application designs the composition of the nucleating agent masterbatch in the rapid forming nylon 66 resin composition, and through the synergistic effect of benzoate, nano-SiO2 and the nylon base, a rapid forming nylon 66 resin composition which can be rapidly crystallized and formed at a higher temperature and has good mechanical properties is prepared.

Description

Technical Field

[0001] This invention belongs to the field of nylon material technology, specifically relating to a rapid prototyping nylon 66 resin composition and its preparation method. Background Technology

[0002] Commonly used nucleating agents for nylon 66 resin are divided into organic and inorganic types. Organic nucleating agents are usually very expensive and some have drawbacks such as poor thermal stability. Inorganic nucleating agents usually have defects such as poor crystal form, difficulty in dispersion, and impact on the toughness, tensile strength, and transparency of nylon 66. Existing technologies have reported the use of a combination of organic and inorganic nucleating agents to achieve synergistic effects. CN103788630A discloses a composite nucleating agent reinforced nylon resin composition, which includes the following blended components: nylon resin, a composite nucleating agent, and an antioxidant; the composite nucleating agent includes an organic nucleating agent and inorganic particles, the organic nucleating agent being a benzoate, and the inorganic particles being one or a combination of halloysite and sepiolite; the amount of the composite nucleating agent is 0.01 to 10 parts by weight of nylon resin per 100 parts by weight. The preparation method includes: mixing nylon 6, sodium benzoate, sepiolite (length between 100 nm and 4 μm), and antioxidants, mixing them in a high-speed mixer, and then adding them to a twin-screw extruder for extrusion and injection molding. Experiments have shown that adding inorganic particles and organic nucleating agents to nylon base materials can significantly improve the mechanical properties of nylon. It has the advantages of low dosage, simple preparation process, and obvious improvement in mechanical properties. More importantly, the compounded nucleating agents show a synergistic effect, that is, the performance of nylon resin can be greatly improved at low addition levels.

[0003] However, existing technologies for combining inorganic and organic nucleating agents often have the following problems: 1) If the inorganic particles are too large, they tend to agglomerate, making them difficult to disperse in nylon resin; 2) If the inorganic particles are too small, they will affect the crystallization of nylon resin and its physical properties. Furthermore, in industrial production, achieving rapid molding without affecting the physical properties of nylon resin products is crucial.

[0004] Therefore, how to provide a novel, high-performance nucleating agent for nylon 66 resin to obtain a rapid-molding nylon 66 resin composition that can be rapidly crystallized at higher temperatures and has good mechanical properties has become an urgent technical problem to be solved. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a rapid prototyping nylon 66 resin composition and its preparation method. The present invention designs the composition of the nucleating agent masterbatch in the rapid prototyping nylon 66 resin composition, and through the synergistic effect of benzoate, nano-SiO2, and nylon matrix, prepares a rapid prototyping nylon 66 resin composition that can rapidly crystallize and mold at higher temperatures and possesses good mechanical properties.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a rapid prototyping nylon 66 resin composition, the rapid prototyping nylon 66 resin composition comprising the following components in parts by weight:

[0008] 100 parts of Nylon 66 resin;

[0009] 5-20 parts of nucleating agent masterbatch;

[0010] The nucleating agent masterbatch includes nylon base material and compound nucleating agent, wherein the compound nucleating agent includes benzoate and nano SiO2;

[0011] Based on the mass percentage of the nucleating agent masterbatch being 100%, the mass percentage of the compound nucleating agent is 5% to 20%.

[0012] In existing technologies, although there are compound nucleating agents that combine inorganic and organic substances, they are mixed in one pot and then added to a twin-screw extruder, which leads to the following problems: 1) Uneven mixing of multiple components and excessively large particle size of inorganic substances, which easily agglomerate, resulting in uneven dispersion in the resin; 2) Crystallization rate that is too fast or too slow affects the crystal morphology, thereby affecting physical properties; 3) In existing technologies, after mixing in one pot and extruding through a twin-screw extruder, there is nylon remelting, which not only leads to a decrease in crystallization rate, but also results in thermo-oxidative aging and mechanical shearing forces caused by the remelting of the nylon finished product, which leads to polymer molecular chain breakage, thereby affecting the physical properties of the polymer (such as tensile strength, flexural modulus, and impact strength).

[0013] The inventors discovered that by selecting appropriate nylon base material, appropriate compound nucleating agent formulation, appropriate ratio of nylon base material and compound nucleating agent, appropriate ratio of nucleating agent masterbatch to nylon 66 resin, and adjusting other conventional preparation parameters in the prior art, the crystallization temperature range of the rapid prototyping nylon 66 resin composition is 204.6–237.3℃, and the crystallization rate is 1.58–1.99 / min. This not only allows for rapid molding of nylon 66, but also results in nylon 66 resin with superior mechanical properties. Optionally, the crystallization temperature can be 204.6℃, 206℃, 208℃, 210℃, 215℃, 220℃, 225℃, 227℃, 229℃, 230℃, 232℃, 234℃, or 235℃. It is worth noting that the starting and ending temperatures within the crystallization temperature range of the same nylon resin composition differ by 10–20℃, for example, by 10℃, 12℃, 15℃, 16℃, 18℃, 19℃, or 20℃. The crystallization rate can be 1.58 / min, 1.60 / min, 1.62 / min, 1.65 / min, 1.67 / min, 1.72 / min, 1.75 / min, 1.78 / min, 1.81 / min, 1.85 / min, 1.88 / min, 1.90 / min, 1.92 / min, 1.95 / min, or 1.98 / min.

[0014] This invention designs the composition of the nucleating agent masterbatch in a rapid-molding nylon 66 resin composition. Through the synergistic effect of benzoate, nano-SiO2, and nylon matrix, and by controlling the amount of the compounded nucleating agent within a specific range, a rapid-molding nylon 66 resin composition capable of rapid crystallization at higher temperatures and possessing good mechanical properties is obtained. If the amount of the compounded nucleating agent is too small, its effect on improving the crystallization rate of nylon 66 resin is limited; if the amount of the compounded nucleating agent is too large, it will accelerate the crystallization rate of nylon 66 resin. An excessively rapid crystallization rate will result in insufficient time for crystals to grow to the optimal size, thus forming more defects and incomplete crystal structures, both of which are detrimental to the mechanical properties of the nylon 66 resin composition.

[0015] To improve the dispersion effect of nucleating agents in nylon 66 resin matrix, this invention first prepares nucleating agent masterbatch, and then uses a twin-screw extruder to blend and compound the nucleating agent with nylon matrix to prepare nucleating agent masterbatch, thereby pre-dispersing the compounded nucleating agent in the nylon matrix. Compared with the prior art of directly adding compounded nucleating agents to nylon 66 resin, this further improves the overall performance of the nylon 66 resin composition.

[0016] This invention not only improves the uniformity of nucleating agent dispersion in the nylon 66 matrix and increases the crystallization rate of nylon 66, but also enhances the dimensional stability and impact resistance of molded parts by combining the low water absorption and flexibility of long-chain carbon nylon. Simultaneously, this invention reduces the number of melt processing steps required for the product, resulting in products with superior physical properties, extended product lifespan, and improved adaptability to subsequent complex processing environments.

[0017] In this invention, the weight percentage of the nucleating agent masterbatch in the rapid prototyping nylon 66 resin composition can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, or 20 parts, etc.

[0018] Based on the mass percentage of the nucleating agent masterbatch being 100%, the mass percentage of the compound nucleating agent is 5% to 20%, for example, it can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%, etc.

[0019] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The objectives and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0020] As a preferred embodiment of the present invention, the benzoate is selected from any one or a combination of at least two of sodium benzoate, potassium benzoate, or calcium benzoate.

[0021] As a preferred embodiment of the present invention, the average particle size of the nano-SiO2 is 25nm to 100nm, for example, it can be 25nm, 26nm, 27nm, 28nm, 29nm, 30nm, 31nm, 32nm, 33nm, 34nm, 35nm, 36nm, 37nm, 38nm, 39nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm or 100nm, etc., preferably 25nm to 100nm.

[0022] In this invention, by controlling the average particle size of nano-SiO2 within a specific range, the nano-SiO2 is easily dispersed and has a large specific surface area, enabling it to better act as a nucleator and accelerate the crystallization rate of nylon 66. This results in a rapid-molding nylon 66 resin composition with a high crystallization temperature, a fast crystallization rate, and good mechanical properties. If the average particle size of nano-SiO2 is too large, it is prone to agglomeration, which is not conducive to dispersion in the nylon matrix, leading to uneven dispersion in the nylon 66 resin and negatively impacting the mechanical properties of nylon 66. If the average particle size of nano-SiO2 is too small, although the crystallization rate increases, the excessively high crystallization rate will prevent the crystals from growing to their optimal size, resulting in more defects and incomplete crystal structures, thus causing a decrease in the mechanical properties of the product.

[0023] As a preferred embodiment of the present invention, the mass ratio of the benzoate to nano-SiO2 is 1:(0.4-2.5), for example, it can be 1:0.4, 1:0.6, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.3 or 1:2.5, etc.

[0024] The amount of sodium benzoate added to the nucleating agent should not be too high. Although increasing the amount of sodium benzoate will further increase the crystallization temperature range of nylon 66, excessively high crystallization temperatures will cause excessively vigorous molecular motion, which is not conducive to the orderly arrangement of crystals, thus resulting in a decrease in the mechanical properties of the product. In this invention, by controlling the mass ratio of benzoate to nano-SiO2 within a specific range, the overall performance of the rapid prototyping nylon 66 resin composition is further optimized.

[0025] As a preferred embodiment of the present invention, the raw materials for preparing the nylon base material include diamine and diacid;

[0026] The molar ratio of the dicarboxylic acid to the diamine is 1:(0.95-1.1), for example, it can be 1:0.95, 1:0.96, 1:0.98, 1:1, 1:1.02, 1:1.04, 1:1.06, 1:08 or 1:1.1, etc.

[0027] The number of carbon atoms in the diamine is ≥4, for example, it can be 4, 5, 6, 8, 10, 12, 13, 14 or 15, etc.

[0028] The number of carbon atoms in the dicarboxylic acid is ≥10, for example, it can be 10, 11, 12, 13, 14, 15, 16, 17 or 18, etc.

[0029] In some preferred embodiments of the present invention, by controlling the number of carbon atoms in the dicarboxylic acid used to prepare the nylon base material to be ≥10, the resulting nylon base material contains alkylene groups with ≥8 carbon atoms between the amide groups, and the water absorption rate of the nylon base material is maintained at 0.1%–0.5% (test conditions: 23°C in water, 24 hours, test method according to ISO 62, water absorption rate of nylon base material 0.1%–0.5% (e.g., 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, or 0.5%, etc.). Simultaneously, the presence of longer alkylene chains in the nylon base material gives it better toughness and flexibility, thereby improving the dimensional stability and impact resistance of the nylon 66 resin composition. Introducing too many longer alkylene chains into the nylon base material would damage the crystallinity of nylon 66, causing a decrease in the mechanical properties of the product.

[0030] Preferably, the number of carbon atoms in the diamine is 4 to 13, for example, 4, 5, 6, 7, 8, 9, 10, 11, 12 or 13.

[0031] Preferably, the number of carbon atoms in the dicarboxylic acid is 10 to 15, for example, 10, 11, 12, 13, 14 or 15.

[0032] In this invention, the number of carbon atoms in the diacid is further controlled to be 10-15, resulting in alkylene groups with 8-13 carbon atoms between the amide groups in the nylon base material, which further optimizes the overall performance of the rapid-molding nylon 66 resin composition. If the number of carbon atoms in the diacid is too high, the chain length of the alkylene groups between the amide groups in the nylon base material will be too long, which will reduce the crystallization rate and mechanical properties of the rapid-molding nylon 66 resin composition.

[0033] As a preferred embodiment of the present invention, the diamine is selected from any one or a combination of at least two of 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,10-diaminodecane, 1,12-diaminododecane, or 1,13-tridecanediamine.

[0034] Preferably, the dicarboxylic acid is selected from any one or a combination of at least two of 1,10-sebacic acid, 1,12-dodecanoic acid, 1,13-tridecanoic acid, 1,14-tetradecanoic acid, or 1,15-pentadecanoic acid.

[0035] It should be noted that this invention does not impose any special limitations on the preparation method of nylon base material. Commonly used methods for preparing nylon materials in the art are applicable, including but not limited to: firstly, a diamine and a diacid are mixed with demineralized water to form a salt, with a molar ratio of diamine to diacid of 1:(0.95-1.1), resulting in a polyamide salt solution with a mass concentration of 50-60%; subsequently, the prepared polyamide salt solution is fed into a concentration tank and concentrated to a mass concentration of 80% under process conditions of 130℃ and 32kPa, before being fed into a polymerization reactor for polycondensation reaction. This polymerization stage is divided into three stages: the first stage is the heating and pressurization stage, utilizing an external heat source. The polyamide salt solution is heated, and the resulting steam increases the pressure in the reactor. Pressure increase is stopped when a certain pressure is reached. At this point, the temperature inside the reactor is generally controlled at around 245℃, and the pressure is 1.75 MPa. After reaching 1.75 MPa, the second stage begins: the heating and pressure holding stage. During this stage, pre-condensation polymerization occurs to generate low molecular weight polymers. The third stage is the isothermal decompression stage: in this stage, steam begins to be discharged from the reactor for dehydration. As moisture is continuously discharged, the temperature gradually increases and the pressure gradually decreases, from 1.75 MPa to atmospheric pressure or slightly negative pressure. This decompression process takes approximately 45 minutes. After the polycondensation reaction is complete, the melt material is extruded through a casting head, cooled, pelletized, and dried to obtain nylon-based material.

[0036] As a preferred embodiment of the present invention, at a test temperature of 23°C and a test time of 24 hours, the water absorption rate of the nylon base material is 0.1% to 0.5% (for example, it can be 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, or 0.5%, etc.).

[0037] The water absorption rate of nylon base material is tested according to ISO 62, and the test conditions are 23°C in water for 24 hours.

[0038] As a preferred embodiment of the present invention, the nucleating agent masterbatch is prepared by the following method, which includes the following steps:

[0039] The nylon base material and the compound nucleating agent are mixed, melt-granulated, and the nucleating agent masterbatch is obtained.

[0040] In this invention, there are no special limitations on the method of mixing nylon base material and compound nucleating agent. Commonly used methods in the art are applicable, including but not limited to: mixing using a mixer, the mixer speed can be 250 rpm, and the time can be 20 min.

[0041] In this invention, the melt granulation method can be to use a twin-screw extruder for melt granulation. The temperature of the twin-screw extruder from the hopper to the die head can be set to: 150℃, 250℃, 260℃, 270℃, 280℃, 280℃, 280℃, 278℃, 275℃, and the screw speed can be 300 rpm.

[0042] As a preferred embodiment of the present invention, the crystallization temperature range of the rapid prototyping nylon 66 resin composition is 204.6–237.3℃ (e.g., 204.6℃, 206℃, 208℃, 210℃, 212℃, 215℃, 218℃, 220℃, 223℃, 225℃, 227℃, 230℃, 233℃, 235℃, 236℃, or 237.3℃, etc.), and the crystallization rate is 1.55–1.98 min. -1 (For example, it could be 1.55min) -1 1.60min -1 1.65min -1 1.70min -1 1.75min -1 1.80min -1 1.85min -1 1.90min -1 1.95min -1 Or 1.98min -1 wait).

[0043] In a second aspect, the present invention provides a method for preparing a rapid prototyping nylon 66 resin composition as described in the first aspect, the method comprising the following steps:

[0044] (1) Mix hexamethylenediamine, adipic acid and water, and carry out a salt formation reaction to obtain a polyamide 66 salt solution. Concentrate the polyamide 66 salt solution to obtain a concentrated polyamide 66 salt solution.

[0045] (2) Place the polyamide 66 salt solution in a prepolymer reactor, react to obtain a prepolymer, and then place it in a flash evaporator to obtain a vapor-liquid mixed bubble polymer.

[0046] (3) Place the foamed polymer in a polymerization reactor to carry out the polymerization reaction and obtain Nylon 66 melt;

[0047] (4) After mixing the molten nucleating agent masterbatch and the nylon 66 melt, the mixture is melt-extruded to obtain the rapid prototyping nylon 66 resin composition.

[0048] As a preferred embodiment of the present invention, the molar ratio of hexamethylenediamine to adipic acid is (1-1.005):1, for example, it can be 1:1, 1:1.001, 1:1.002, 1:1.003, 1:1.004 or 1:1.005, etc.

[0049] Preferably, the polyamide 66 salt solution has a mass concentration of 50% to 60% (e.g., 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, or 60%) and a pH of 7.20 to 7.70 (e.g., 7.20, 7.30, 7.40, 7.50, 7.60, or 7.70).

[0050] Preferably, the concentration temperature in step (1) is 120℃~150℃ (e.g., 120℃, 122℃, 125℃, 127℃, 130℃, 133℃, 136℃, 139℃, 141℃, 144℃, 146℃ or 150℃, etc.), and the pressure is 15kPa~60kPa (e.g., 15kPa, 20kPa, 25kPa, 30kPa, 35kPa, 40kPa, 45kPa, 50kPa, 55kPa or 60kPa, etc.).

[0051] Preferably, the mass concentration of the concentrated polyamide 66 salt solution is 65% to 75%, for example, it can be 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, or 75%.

[0052] Preferably, the reaction temperature in step (2) is 210℃~250℃ (e.g., it can be 210℃, 215℃, 220℃, 225℃, 230℃, 235℃, 240℃, 245℃ or 250℃, etc.), the pressure is 1.3MPa~1.5MPa (e.g., it can be 1.3MPa, 1.32MPa, 1.34MPa, 1.36MPa, 1.38MPa, 1.4MPa, 1.42MPa, 1.44MPa, 1.46MPa, 1.48MPa or 1.5MPa, etc.), and the time is 1.5h~3h (e.g., it can be 1.5h, 1.7h, 1.9h, 2h, 2.2h, 2.5h, 2.8h or 3h, etc.).

[0053] Preferably, the outlet pressure of the flash vapor is 0 to 0.05 MPa (e.g., 0 MPa, 0.01 MPa, 0.02 MPa, 0.03 MPa, 0.04 MPa, or 0.05 MPa, etc.), and the temperature is 270°C to 280°C (e.g., 270°C, 271°C, 272°C, 273°C, 274°C, 275°C, 276°C, 277°C, 278°C, 279°C, or 280°C, etc.).

[0054] Preferably, the polymerization reaction in step (3) is carried out at a temperature of 270℃ to 310℃ (e.g., 270℃, 272℃, 275℃, 278℃, 281℃, 284℃, 286℃, 288℃, 290℃, 293℃, 296℃, 299℃, 302℃, 305℃, 308℃, or 310℃, etc.), at a pressure of -40kPa to 5kPa (e.g., -40kPa, -35kPa, -30kPa, -25kPa, -20kPa, -15kPa, -10kPa, -5kPa, 0kPa, or 5kPa, etc.), and for a time of 30min to 60min (e.g., 30min, 35min, 40min, 45min, 50min, 55min, or 60min, etc.).

[0055] As a preferred embodiment of the present invention, the preparation method of the rapid prototyping nylon 66 resin composition specifically includes the following steps:

[0056] (1) Add hexamethylenediamine, adipic acid and water to a salting tank and mix them. The molar ratio of hexamethylenediamine to adipic acid is (1~1.005):1. The salting reaction is carried out to obtain a polyamide 66 salt solution with a mass concentration of 50%~60% and a pH of 7.20-7.70. The solution is concentrated at 120℃~150℃ and 15kPa~60kPa to obtain a polyamide 66 salt solution with a mass concentration of 65%~75%.

[0057] (2) Place the polyamide 66 salt solution in a prepolymer reactor and react it at 210℃~250℃ and 1.3MPa~1.5MPa for 1.5h~3h to obtain the prepolymer. Then place it in a flash evaporator and set the outlet pressure of the flash vapor to 0~0.05MPa and the temperature to 270℃~280℃ to obtain a vapor-liquid mixed bubble polymer.

[0058] (3) Place the foamed polymer in a polymerization reactor and carry out the polymerization reaction at 270℃~310℃ and -40kPa~5kPa for 30min~60min to obtain Nylon 66 melt;

[0059] (4) The molten nucleating agent masterbatch is placed in the nylon 66 melt and melt-extruded to obtain the rapid prototyping nylon 66 resin composition.

[0060] Compared with the prior art, the present invention has the following beneficial effects:

[0061] This invention designs the composition of the nucleating agent masterbatch in the rapid prototyping nylon 66 resin composition. Through the synergistic effect of benzoate, nano-SiO2 and nylon matrix, and by controlling the amount of compound nucleating agent within a specific range, a rapid prototyping nylon 66 resin composition that can be rapidly crystallized at higher temperatures and has good mechanical properties is prepared. Detailed Implementation

[0062] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0063] The sources of some components in the examples and comparative examples are shown in Table 1 below:

[0064] Table 1

[0065]

[0066]

[0067] It should be noted that, in the following examples and comparative examples, the weight ratio of the molten nucleating agent masterbatch to the nylon 66 melt in step (4) of the preparation method of the rapid prototyping nylon 66 resin composition is the same as the weight ratio of the nylon 66 resin to the nucleating agent masterbatch.

[0068] Example 1

[0069] This embodiment provides a rapid prototyping nylon 66 resin composition and its preparation method. The rapid prototyping nylon 66 resin composition comprises the following components in parts by weight:

[0070] 100 parts of Nylon 66 resin;

[0071] 12 parts of nucleating agent masterbatch;

[0072] The nucleating agent masterbatch includes nylon base material and compound nucleating agent, wherein the compound nucleating agent is composed of sodium benzoate and nano SiO2-30 in a mass ratio of 1:1;

[0073] With the nucleating agent masterbatch having a mass percentage content of 100%, the compound nucleating agent has a mass percentage content of 10%.

[0074] The preparation method of the nylon base material is as follows:

[0075] 1,6-Hexamethylenediamine and 1,10-Sebacic acid were mixed with demineralized water to form a salt solution with a molar ratio of 1:1. The resulting polyamide salt solution had a mass concentration of 55%. The prepared polyamide salt solution was then fed into a concentration tank and concentrated to a mass concentration of 80% under process conditions of 130℃ and 32kPa. This concentrated solution was then fed into a polymerization reactor for polycondensation. This polymerization stage consisted of three phases: the first phase was the heating and pressurization phase, where an external heat source was used to heat the polyamide salt solution. The generated steam increased the reactor pressure. Pressurization was stopped when a certain pressure was reached, and the temperature inside the reactor was generally controlled at 2℃. At approximately 45℃ and a pressure of 1.75MPa, the process begins in the second stage: a heating and pressure holding stage. During this stage, pre-condensation polymerization occurs to generate low molecular weight polymers. The third stage is a constant temperature and pressure release stage: water vapor begins to be discharged from the reactor for dehydration. As water is continuously discharged, the temperature gradually increases and the pressure gradually decreases, from 1.75MPa to atmospheric pressure or slightly negative pressure. This pressure release process takes approximately 45 minutes. After the condensation reaction is complete, the melt material is extruded through a casting strip, cooled, pelletized, and dried to obtain nylon base material. The test method follows ISO 62, with test conditions of 23℃ and 24h. The water absorption rate of the nylon base material is measured to be 0.3%.

[0076] The preparation method of the nucleating agent masterbatch is as follows:

[0077] The nylon base material and the compound nucleating agent were placed in a mixer and mixed at 250 rpm for 20 min. The mixture was then melt-granulated using a twin-screw extruder to obtain the nucleating agent masterbatch.

[0078] The temperature from the hopper to the die head of the twin-screw extruder can be set to: 150℃, 250℃, 260℃, 270℃, 280℃, 280℃, 278℃, 275℃, and the screw speed can be 300 rpm.

[0079] The preparation method of the above-mentioned rapid prototyping nylon 66 resin composition specifically includes the following steps:

[0080] (1) Add hexamethylenediamine, adipic acid and water to a salting tank and mix them. After the salting reaction, a nylon 66 salt solution is obtained. The pH value of the nylon 66 salt solution is adjusted to 7.40, the mass percentage is 57%, and the molar ratio of hexamethylenediamine and adipic acid is 1:1.

[0081] A 57% concentration salt solution was sent to a concentration tank and concentrated under process conditions of 120℃ and 32kPa to obtain a 70% mass concentration nylon 66 salt solution.

[0082] (2) The polyamide 66 salt solution was placed in a prepolymer reactor and reacted at 230℃ and 1.4MPa for 2h to obtain the prepolymer. Then, it was placed in a flash evaporator and heated to 280℃ within 3s. The outlet pressure of the flash vapor was set to 0.03MPa and the temperature to 280℃ to obtain a vapor-liquid mixed bubble polymer.

[0083] (3) Place the foamed polymer in a polymerization reactor and carry out the polymerization reaction at 275℃ and -18kPa for 50 minutes to obtain Nylon 66 melt;

[0084] (4) The molten nucleating agent masterbatch is placed in nylon 66 melt, melt-extruded by a screw extruder, cooled, pelletized and dried to obtain the rapid prototyping nylon 66 resin composition;

[0085] Among them, the twin-screw extruder maintains the barrel temperature at 150℃, 250℃, 260℃, 270℃, 280℃, 280℃, 278℃, and 275℃ from the hopper to the die head, and the screw speed is 260 rpm.

[0086] Example 2

[0087] This embodiment provides a rapid prototyping nylon 66 resin composition and its preparation method. The rapid prototyping nylon 66 resin composition comprises the following components in parts by weight:

[0088] 100 parts of Nylon 66 resin;

[0089] 8 parts of nucleating agent masterbatch;

[0090] The nucleating agent masterbatch includes nylon base material and compound nucleating agent, wherein the compound nucleating agent is composed of sodium benzoate and nano SiO2-80 in a mass ratio of 1:2;

[0091] With the nucleating agent masterbatch having a mass percentage content of 100%, the compound nucleating agent has a mass percentage content of 8%.

[0092] The preparation method of the nylon base material is the same as that in Example 1;

[0093] The preparation method of the above-mentioned rapid prototyping nylon 66 resin composition is the same as that in Example 1.

[0094] Example 3

[0095] This embodiment provides a rapid prototyping nylon 66 resin composition and its preparation method. The rapid prototyping nylon 66 resin composition comprises the following components in parts by weight:

[0096] 100 parts of Nylon 66 resin;

[0097] 15 parts of nucleating agent masterbatch;

[0098] The nucleating agent masterbatch includes nylon base material and compound nucleating agent, wherein the compound nucleating agent is composed of sodium benzoate and nano SiO2-30 in a mass ratio of 1:0.5;

[0099] With the nucleating agent masterbatch having a mass percentage content of 100%, the compound nucleating agent has a mass percentage content of 16%.

[0100] The preparation method of the nylon base material is the same as that in Example 1;

[0101] The preparation method of the above-mentioned rapid prototyping nylon 66 resin composition is the same as that in Example 1.

[0102] Examples 4-14

[0103] Examples 4-14 each provide a rapid prototyping nylon 66 resin composition and its preparation method, differing from Example 1 only in that:

[0104] Example 4: The compound nucleating agent is composed of sodium benzoate and nano-SiO2-30 in a mass ratio of 1:0.4;

[0105] Example 5: The compound nucleating agent is composed of sodium benzoate and nano-SiO2-30 in a mass ratio of 1:3;

[0106] Example 6: The compound nucleating agent is composed of sodium benzoate and nano-SiO2-100 in a mass ratio of 1:1;

[0107] Example 7: The compound nucleating agent is composed of sodium benzoate and nano-SiO2-200 in a mass ratio of 1:1;

[0108] Example 8: Based on the mass percentage of the nucleating agent masterbatch being 100%, the mass percentage of the compound nucleating agent is 5%.

[0109] Example 9: Based on the mass percentage of the nucleating agent masterbatch being 100%, the mass percentage of the compound nucleating agent is 20%.

[0110] Example 10: The nucleating agent masterbatch in the rapid prototyping nylon 66 resin composition is 5 parts by weight;

[0111] Example 11: The nucleating agent masterbatch in the rapid prototyping nylon 66 resin composition is 20 parts by weight;

[0112] Example 12: The 1:1 molar ratio of 1,6-hexanediamine and 1,10-sebacic acid used in the preparation of the nylon base material in Example 1 was replaced with a 1:1 molar ratio of 1,6-hexanediamine and 1,6-adipic acid. The water absorption rate of the nylon base material was tested according to ISO 62, under the conditions of 23°C and 24h, and the water absorption rate of the nylon base material was found to be 0.6%.

[0113] Example 13: The 1,6-hexanediamine and 1,10-sebacic acid molar ratio of the raw materials used in the preparation of the nylon base material in Example 1 were replaced with 1,6-hexanediamine and 1,16-hexadecanoic acid molar ratio of 1:1.

[0114] Example 14: The preparation method of the rapid prototyping nylon 66 resin composition specifically includes the following steps:

[0115] (1) Add hexamethylenediamine, adipic acid and water to a salting tank and mix them. After the salting reaction, a nylon 66 salt solution is obtained. The pH value of the nylon 66 salt solution is adjusted to 7.40, the mass percentage is 57%, and the molar ratio of hexamethylenediamine and adipic acid is 1:1.

[0116] A 57% concentration salt solution was sent to a concentration tank and concentrated under process conditions of 120℃ and 32kPa to obtain a 70% mass concentration nylon 66 salt solution.

[0117] (2) The polyamide 66 salt solution was placed in a prepolymer reactor and reacted at 230℃ and 1.4MPa for 2h to obtain the prepolymer. Then, it was placed in a flash evaporator and heated to 280℃ within 3s. The outlet pressure of the flash vapor was set to 0.03MPa and the temperature to 280℃ to obtain a vapor-liquid mixed bubble polymer.

[0118] (3) Place the foamed polymer in a polymerization kettle and carry out the polymerization reaction at 275℃ and -18kPa for 50 min. Then, melt-extrude the polymer through a screw extruder, cool, pelletize and dry to obtain nylon 66 resin.

[0119] Among them, the twin-screw extruder maintains the barrel temperature at 150℃, 250℃, 260℃, 270℃, 280℃, 280℃, 278℃, and 275℃ from the hopper to the die head, and the screw speed is 260 rpm.

[0120] (4) Mix the nucleating agent masterbatch and nylon 66 resin, melt-extrude the mixture through a screw extruder, cool, pelletize and dry to obtain the rapid prototyping nylon 66 resin composition;

[0121] Among them, the twin-screw extruder maintains the barrel temperature at 150℃, 250℃, 260℃, 270℃, 280℃, 280℃, 278℃, and 275℃ from the hopper to the die head, and the screw speed is 260 rpm.

[0122] Other conditions are the same as in Example 1.

[0123] Comparative Examples 1-6

[0124] Comparative Examples 1-6 each provide a rapid prototyping nylon 66 resin composition and its preparation method, differing from Example 1 only in that:

[0125] Comparative Example 1: Based on the mass percentage of the nucleating agent masterbatch being 100%, the mass percentage of the compound nucleating agent is 3%.

[0126] Comparative Example 2: Based on the mass percentage of the nucleating agent masterbatch being 100%, the mass percentage of the compound nucleating agent is 25%.

[0127] Comparative Example 3: The nucleating agent masterbatch in the rapid prototyping nylon 66 resin composition is 3 parts by weight;

[0128] Comparative Example 4: The nucleating agent masterbatch in the rapid prototyping nylon 66 resin composition is 25 parts by weight;

[0129] Comparative Example 5: The nucleating agent masterbatch includes nylon base material and nucleating agent, wherein the nucleating agent is sodium benzoate and does not contain SiO2-30;

[0130] Comparative Example 6: The nucleating agent masterbatch includes nylon base material and nucleating agent, wherein the nucleating agent is nano SiO2-30 and does not contain sodium benzoate;

[0131] Other conditions are the same as in Example 1.

[0132] Comparative Example 7

[0133] This comparative example provides a rapid prototyping nylon 66 resin composition and its preparation method. The only difference between this example and Example 9 is that 12 parts by weight of the nucleating agent masterbatch are replaced with 2.4 parts by weight of the compound nucleating agent (i.e., the nucleating agent masterbatch does not include nylon base material, and the amount of compound nucleating agent added to the nylon 66 resin composition remains unchanged). Everything else is the same as Example 9.

[0134] The properties of the rapid prototyping nylon 66 resin compositions provided in the above embodiments and comparative examples were characterized using the following specific test methods:

[0135] (1) The crystallization properties of the samples were tested using a DSC instrument. The specific steps are as follows:

[0136] Under nitrogen protection, the temperature was increased from 50℃ to 300℃ at a rate of 10℃ / min, held at 300℃ for 3 minutes to eliminate thermal history, then decreased to 50℃ at a rate of 20℃ / min, followed by a further increase to 300℃ at a rate of 10℃ / min, and held at 300℃ for 1 minute. The DSC curve of the prepared nylon 66 product was obtained. This curve reveals the crystallization temperature range of the nylon 66 product. The crystallization rate is calculated as follows: Crystallization rate = (Crystallization initiation time - Crystallization peak time) -1 Unit: min -1 .

[0137] (2) Tensile strength: Refer to GB / T 1040.1, test the tensile strength of the sample after injection molding.

[0138] (3) Notched impact strength of simply supported beam: Refer to GB / T 1043.1, test the notched impact strength of simply supported beam of the sample after injection molding.

[0139] Water absorption rate of nylon base material: tested according to ISO 62, under the conditions of 23°C in water for 24 hours.

[0140] The performance test results are shown in Table 2 below:

[0141] Table 2

[0142]

[0143]

[0144] This invention designs the composition of the nucleating agent masterbatch in a rapid-molding nylon 66 resin composition. Through the synergistic effect of benzoate, nano-SiO2, and nylon matrix, and by controlling the amount of the compounded nucleating agent within a specific range, a rapid-molding nylon 66 resin composition capable of rapid crystallization at relatively high temperatures and exhibiting good mechanical properties is obtained. The crystallization temperature range is 204.6–237.3℃, and the crystallization rate is 1.58–1.99 min. -1 The tensile strength is 66.7-78.8 MPa, and the notched impact strength of the simply supported beam is 4.4-6.7 kJ / m. 2 .

[0145] Furthermore, this invention optimizes the overall performance of the rapid prototyping nylon 66 resin composition by designing the specific composition of the nucleating agent masterbatch, including designing the mass ratio of benzoate and nano-SiO2 with a specific particle size within a specific range, and selecting diamines and diacids with specific chain lengths to prepare the nylon base material. The crystallization temperature range is 210.9–237.3℃, and the crystallization rate is 1.62–1.99 min. -1The tensile strength is 68.7-78.8 MPa, and the notched impact strength of the simply supported beam is 5.2-6.7 kJ / m. 2 .

[0146] As can be seen from the comparisons between Example 1 and Comparative Examples 1-6, and Example 9 and Comparative Example 7, this application designs the composition of the nucleating agent masterbatch in the rapid prototyping nylon 66 resin composition. Through the synergistic effect of benzoate, nano-SiO2 and nylon base material, and at the same time, the present invention controls the amount of compound nucleating agent within a specific range, thus preparing a rapid prototyping nylon 66 resin composition with excellent performance.

[0147] In summary, this invention designs the composition of the nucleating agent masterbatch in the rapid prototyping nylon 66 resin composition. Through the synergistic effect of benzoate, nano-SiO2 and nylon matrix, and by controlling the amount of compounded nucleating agent within a specific range, this invention prepares a rapid prototyping nylon 66 resin composition that can rapidly crystallize and form at higher temperatures and has good mechanical properties.

[0148] The applicant declares that the detailed process flow of this invention is illustrated by the above embodiments, but this invention is not limited to the above detailed process flow, that is, it does not mean that this invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the product of this invention, addition of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

Claims

1. A rapid prototyping nylon 66 resin composition, characterized in that, The rapid prototyping nylon 66 resin composition comprises the following components in parts by weight: 100 parts of Nylon 66 resin; 5-20 parts of nucleating agent masterbatch; The nucleating agent masterbatch includes nylon base material and compound nucleating agent, wherein the compound nucleating agent includes benzoate and nano SiO2; Based on the mass percentage of the nucleating agent masterbatch being 100%, the mass percentage of the compound nucleating agent is 5% to 20%.

2. The rapid prototyping nylon 66 resin composition according to claim 1, characterized in that, The benzoate is selected from any one or a combination of at least two of sodium benzoate, potassium benzoate, or calcium benzoate.

3. The rapid prototyping nylon 66 resin composition according to claim 1 or 2, characterized in that, The average particle size of the nano-SiO2 is 25nm to 200nm, preferably 25nm to 100nm.

4. The rapid prototyping nylon 66 resin composition according to any one of claims 1-3, characterized in that, The mass ratio of the benzoate to nano-SiO2 is 1:(0.4-2.5).

5. The rapid prototyping nylon 66 resin composition according to any one of claims 1-4, characterized in that, The raw materials for preparing the nylon base material include diamines and diacids; The molar ratio of the diacid to the diamine is 1:(0.95-1.1); The number of carbon atoms in the diamine is ≥4; The number of carbon atoms in the dicarboxylic acid is ≥10; Preferably, the number of carbon atoms in the diamine is 4 to 13; Preferably, the number of carbon atoms in the dicarboxylic acid is 10 to 15; Preferably, the diamine is selected from any one or a combination of at least two of 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,10-diaminodecane, 1,12-diaminododecane, or 1,13-tridecanediamine. Preferably, the dicarboxylic acid is selected from any one or a combination of at least two of 1,10-sebacic acid, 1,12-dodecanoic acid, 1,13-tridecanoic acid, 1,14-tetradecanoic acid, or 1,15-pentadecanoic acid. Preferably, at a test temperature of 23°C and a test time of 24 hours, the water absorption rate of the nylon base material is 0.1% to 0.5%.

6. The rapid prototyping nylon 66 resin composition according to any one of claims 1-5, characterized in that, The nucleating agent masterbatch is prepared by the following method, which includes the following steps: The nylon base material and the compound nucleating agent are mixed, melt-granulated, and the nucleating agent masterbatch is obtained.

7. The rapid prototyping nylon 66 resin composition according to any one of claims 1-6, characterized in that, The crystallization temperature range of the rapid prototyping nylon 66 resin composition is 204.6–237.3℃, and the crystallization rate is 1.58–1.99 min. -1 .

8. A method for preparing a rapid prototyping nylon 66 resin composition as described in any one of claims 1-7, characterized in that, The preparation method includes the following steps: (1) Mix hexamethylenediamine, adipic acid and water, and carry out a salt formation reaction to obtain a polyamide 66 salt solution. Concentrate the polyamide 66 salt solution to obtain a concentrated polyamide 66 salt solution. (2) Place the polyamide 66 salt solution in a prepolymer reactor, react to obtain a prepolymer, and then place it in a flash evaporator to obtain a vapor-liquid mixed bubble polymer. (3) Place the foamed polymer in a polymerization reactor to carry out the polymerization reaction and obtain Nylon 66 melt; (4) After mixing the molten nucleating agent masterbatch with the nylon 66 melt, the mixture is melt-extruded to obtain the rapid prototyping nylon 66 resin composition.

9. The preparation method according to claim 8, characterized in that, The molar ratio of hexamethylenediamine to adipic acid is (1-1.005):1; Preferably, the polyamide 66 salt solution has a mass concentration of 50% to 60% and a pH of 7.20 to 7.70; Preferably, the concentration temperature in step (1) is 120℃~150℃ and the pressure is 15kPa~60kPa; Preferably, the mass concentration of the concentrated polyamide 66 salt solution is 65% to 75%. Preferably, the reaction in step (2) is carried out at a temperature of 210°C to 250°C, a pressure of 1.3 MPa to 1.5 MPa, and a time of 1.5 h to 3 h. Preferably, the outlet pressure of the flash vapor is 0 to 0.05 MPa and the temperature is 270°C to 280°C.

10. The preparation method according to claim 8 or 9, characterized in that, The polymerization reaction in step (3) is carried out at a temperature of 270℃~310℃, a pressure of -40kPa~5kPa, and a time of 30min~60min.

Images