A low-hardness polyurethane 3D heart model printing material and preparation method thereof

Abstract

The present invention discloses a low-hardness polyurethane 3D heart model printing material and a preparation method thereof. The low-hardness polyurethane 3D heart model printing material of the present invention comprises, by weight, 79.7 to 89.7 parts of thermoplastic polyurethane; 10 to 20 parts of acrylic modified polyurethane; 0.2 to 2 parts of a compatibilizer; 0.1 to 0.3 parts of an antioxidant; wherein the compatibilizer contains an epoxy group. The low-hardness polyurethane 3D heart model printing material of the present invention uses thermoplastic polyurethane as a base resin, is used in combination with acrylic modified polyurethane, and is combined with a compatibilizer containing an epoxy group. The three work synergistically, while reducing the hardness of the thermoplastic polyurethane, it can also maintain good light transmittance.

Description

Technical Field

[0001] The present invention relates to the technical field of compositions of polymer compounds, and more specifically, to a low-hardness polyurethane 3D heart model printing material and a preparation method thereof. Background Art

[0002] Atrial fibrillation (AF) is the most common clinical tachyarrhythmia. Data show that the total number of AF patients has exceeded 30 million. In severe cases, it can cause cardiovascular and cerebrovascular diseases, leading to thromboembolism and heart failure. The incidence of stroke is 5 times higher than that of the general population, heart failure is 3 times higher, and the overall mortality rate is twice that of people without AF. The Framjngham study showed that AF is an independent risk factor for cerebrovascular embolic events. Therefore, in patients who cannot convert to sinus rhythm, preventing cardiovascular and cerebrovascular embolic events is the primary task of treating AF. In patients with non-valvular AF, 86-91% of the thrombi that cause embolic events originate from the heart, and most of them are formed in the left atrial appendage. In recent years, the emergence of transcatheter left atrial appendage occlusion has provided a new option for preventing cerebrovascular embolic events in AF patients. Using an interventional approach to close the left atrial appendage reduces the occurrence of complications in patients with AF and solves various problems caused by long-term use of warfarin. Since transcatheter LAA occlusion is complicated, the commonly used occlusion devices include Watchman, ACP, Lambre, LARIT, etc. Different occlusion devices have different requirements for anatomical assessment of the LAA. In addition, the LAA of normal people has great variability, and there are many anatomical types: common anatomical types include weather vane type, cauliflower type, cactus type, chicken wing type, etc. At the same time, there are rare LAA anatomical forms such as large bilobed type and angular type. The variable LAA anatomical structure may make it difficult to place the occlusion umbrella, and the occlusion device may be repeatedly recovered, reset or replaced, which may easily cause LAA damage and increase the risk of thrombosis and pericardial tamponade. Although the current imaging technologies such as multi-slice spiral computed tomography (CT), magnetic resonance (MR), and echocardiography have become increasingly mature in the diagnosis of this type of complex CHD and can perform three-dimensional imaging, observing three-dimensional images on a limited two-dimensional screen cannot directly obtain more intuitive anatomical details, and it is even more impossible to provide a three-dimensional anatomical model for the operator to simulate the surgical operation before surgery.

[0003] 3D printing technology has the advantages of digitalization, personalized manufacturing and no need for molds. In recent years, it has gradually begun to be clinically applied in the fields of orthopedics, dentistry, neurosurgery, etc., especially 3D printed heart models help people to accurately, finely and intuitively understand the complex anatomical spatial relationship of heart lesions, and help to refine diagnosis, develop heart models, formulate surgical and interventional treatment plans before surgery, simulate cardiac surgery operations, etc., providing strong support for preoperative evaluation of left atrial appendage occlusion and complex left atrial appendage occlusion strategies.

[0004] However, commonly used 3D printing materials such as PLA, ABS, nylon, etc. are relatively hard and cannot print flexible samples that can simulate the heart. In order to obtain flexible 3D printing materials, thermoplastic polyurethane (TPU) with a lower hardness than the above materials is usually selected. For example, the prior art discloses a 3D printing method for flexible composite materials based on thermoplastic polyurethane, in which a foaming agent is used to improve the hardness of thermoplastic polyurethane. However, the composite material prepared by this method has a low transparency due to the presence of the foaming agent and cannot be used to print heart models, let alone left atrial appendage anatomical models. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects and shortcomings of existing polyurethane 3D printing composite materials that cannot have both low hardness and high transmittance, and to provide a low-hardness polyurethane 3D heart model printing material, which uses thermoplastic polyurethane as a matrix resin, is matched with acrylic modified polyurethane, and is combined with a compatibilizer containing an epoxy group. The three work synergistically to reduce the hardness of the thermoplastic polyurethane while maintaining excellent light transmittance.

[0006] Another object of the present invention is to provide a method for preparing a low-hardness polyurethane 3D heart model printing material.

[0007] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0008] A low-hardness polyurethane 3D heart model printing material, comprising the following components by weight:

[0009]

[0010] Wherein, the compatibilizer contains epoxy groups.

[0011] The present invention uses acrylic modified polyurethane as a modifier to effectively reduce the hardness of thermoplastic polyurethane while maintaining good transparency, and the epoxy group in the compatibilizer can react with acrylic acid in the acrylic modified polyurethane, thereby improving the compatibility between thermoplastic polyurethane and acrylic modified polyurethane, avoiding the precipitation of acrylic modified polyurethane to increase the hardness of the composite material and reduce transparency. The addition of polycarbodiimide can improve the yellowing resistance of the material and avoid the shortcomings of increased melt flow index and decreased tensile strength caused by hydrolysis during processing.

[0012] Preferably, the low-hardness polyurethane 3D heart model printing material comprises the following components by weight:

[0013]

[0014]

[0015] In a specific embodiment, the thermoplastic polyurethane of the present invention adopts GB / T 2410-2008 standard, and its mass melt flow rate is 30-50g / 10min when measured at 190°C and 3.8kg. Specifically, the mass melt flow rate of the thermoplastic polyurethane is 30g / 10min, 40g / 10min, 50g / 10min, and the preferred mass melt flow rate of the thermoplastic polyurethane is 40g / 10min.

[0016] The hardness (Shore A) of the thermoplastic polyurethane of the present invention is 60A-65A.

[0017] In a specific embodiment, the viscosity of the acrylic modified polyurethane of the present invention is 3000-30000 CPS (25° C.). Specifically, the viscosity of the acrylic modified polyurethane is 3000-8000 CPS (25° C.), 10000-15000 CPS (25° C.), or 15000-30000 CPS (25° C.).

[0018] Specifically, the antioxidant of the present invention is polycarbodiimide. The addition of polycarbodiimide can improve the yellowing resistance of the composite material and can also prevent the melt mass flow rate from increasing and the tensile strength from decreasing due to hydrolysis of the composite material during processing.

[0019] Specifically, the compatibilizer of the present invention is polypropylene glycol diglycidyl ether, and the number average molecular weight of the polypropylene glycol diglycidyl ether is 360-400.

[0020] The present invention also protects a method for preparing a low-hardness polyurethane 3D heart model printing material, comprising the following steps:

[0021] Thermoplastic polyurethane, acrylic modified polyurethane, a compatibilizer and an antioxidant are uniformly mixed, melt-extruded and granulated to obtain a low-hardness polyurethane 3D heart model printing material.

[0022] Specifically, the method for preparing the above-mentioned low-hardness polyurethane 3D heart model printing material comprises the following steps:

[0023] S1. The acrylic modified polyurethane and the compatibilizer are mixed evenly, and then an antioxidant is added and mixed evenly to form a premix;

[0024] S2. Add the premix and thermoplastic polyurethane described in S1 to a twin-screw extruder, melt-extrude and granulate to obtain a low-hardness polyurethane 3D heart model printing material;

[0025] Wherein, the aspect ratio of the twin-screw extruder is ≥40:1, the extrusion temperature is 150-190°C, and the rotation speed is 100-400rmp.

[0026] Specifically, when the compatibilizer is polypropylene glycol diglycidyl ether and the antioxidant is polycarbodiimide, since the acrylic modified polyurethane and the compatibilizer polypropylene glycol diglycidyl ether are both liquids, the antioxidant polycarbodiimide can be dissolved to form a uniform solution after mixing, which can be better mixed with the thermoplastic polyurethane.

[0027] In addition, the low-hardness polyurethane 3D heart model printing material can also be prepared by first mixing and then extruding and granulating, which specifically includes the following steps:

[0028] S1. Accurately weigh the acrylic modified polyurethane, compatibilizer and antioxidant according to the formula, first mix the acrylic modified polyurethane and the compatibilizer, and then add the antioxidant and mix well to form a premix;

[0029] S2. Accurately weigh the thermoplastic polyurethane according to the formula and add it to the mixing chamber of the internal mixer, set the temperature to 180 ° C, the rotor speed to 25 to 40 rpm, and mix for 3 to 6 minutes; then add the premix described in S1 and mix for 3 to 6 minutes to complete the mixing;

[0030] S3. Add the mixed material in S2 into the hopper of the single screw extruder, extrude and granulate at a temperature of 170-190° C. and a main engine speed of 100-400 rpm to obtain a low-hardness polyurethane 3D heart model printing material.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The acrylic modified polyurethane used in the present invention has good compatibility with thermoplastic polyurethane, which can reduce the hardness of the material while improving its fluidity and maintaining good transparency;

[0033] (2) The present invention uses polypropylene glycol diglycidyl ether as a compatibilizer, and can utilize the epoxy group in its molecule to react with acrylic modified polyurethane, thereby solving the problem of surface precipitation and stickiness when the acrylic modified polyurethane content is high;

[0034] (3) The addition of polycarbodiimide as an antioxidant in the present invention can effectively prevent the material from oxidizing and yellowing and from degradation caused by trace amounts of moisture during processing. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0036] 1. Raw materials and reagents

[0037] Thermoplastic polyurethane 1, with a mass melt flow rate of 50 g / 10 min and a hardness of 63A measured according to GB / T 2410-2008 standard, brand Elastollan S60AP, ​​and manufacturer BASF, Germany;

[0038] Thermoplastic polyurethane 2, with a mass melt flow rate of 40 g / 10 min and a hardness of 60A measured according to GB / T 2410-2008 standard, brand Elastollan C60AP, ​​and manufactured by BASF, Germany;

[0039] Thermoplastic polyurethane 3, with a mass melt flow rate of 30 g / 10 min and a hardness of 65A as measured according to GB / T 2410-2008 standard, brand Elastollan 565AP, and manufacturer BASF, Germany;

[0040] Acrylic modified polyurethane copolymer 1, with a viscosity of 3000-8000, brand DH-JZ002, manufacturer Nanxiong Dinghao Photochemical Technology Co., Ltd.;

[0041] Acrylic modified polyurethane copolymer 2, with a viscosity of 10000-15000, brand DH-JZ004, manufacturer Nanxiong Dinghao Photochemical Technology Co., Ltd.;

[0042] Acrylic modified polyurethane copolymer 3, with a viscosity of 15000-30000, brand DH-JZ001, manufacturer Nanxiong Dinghao Photochemical Technology Co., Ltd.

[0043] The compatibilizer is polypropylene glycol diglycidyl ether, with a number average molecular weight of 380, brand Mn380, and the manufacturer is Aladdin Company;

[0044] The antioxidant is polycarbodiimide, brand UN-03, produced by Shanghai Youen Chemical Co., Ltd.

[0045] 2. Performance Testing

[0046] (1) Tensile strength and elongation at break

[0047] The low-hardness polyurethane 3D heart model printing material of each embodiment and comparative example was formed into a sheet with a thickness of 1 mm by hot pressing, and tensile strips meeting the requirements of national standards were punched out. The tensile strength and elongation at break were tested according to the method described in GB / T1040.3-2006, and the tensile rate was 200 mm / min.

[0048] (2) Hardness

[0049] The low-hardness polyurethane 3D heart model printing materials of each embodiment and comparative example were hot-pressed to form cylindrical samples with a diameter of 12 mm and a thickness of 6 mm, and the hardness was tested according to the method described in GB / T 531-1999.

[0050] (3) Light transmittance

[0051] The light transmittance was tested according to the method described in GB / T 2410-2008, and the sample thickness was 1 mm.

[0052] (4) 3D printing performance

[0053] The 3D printing performance is evaluated based on four aspects: whether the material is stuck during the printing process, base plate adhesion, printing accuracy and interlayer adhesion. If the above four aspects are all good, it is evaluated as excellent; if there is a problem in one aspect, it is evaluated as good; if there are problems in two aspects, it is evaluated as average; if there are problems in all four aspects, it is evaluated as poor.

[0054] (5) Surface precipitation

[0055] The low-hardness polyurethane 3D heart model printing material of each embodiment and comparative example was made into a sample with a thickness of 1 mm and placed under natural conditions for 14 days. Then, a piece of filter paper was placed on the upper and lower sides of the sample. A 5 kg weight was loaded on the filter paper for static pressure for 24 hours. Then, the surface of the filter paper was observed for traces of oil to evaluate the surface precipitation.

[0056] (6) Yellowing resistance grade

[0057] The low-hardness polyurethane 3D heart model printing material of each embodiment and comparative example was made into a sample with a thickness of 1 mm and baked in an oven at 80° C. for 168 h. The yellowing resistance grade of the material was evaluated according to the method described in GB 250-1995.

[0058] Examples 1 to 7

[0059] The weight proportions of the components of the low hardness polyurethane 3D heart model printing materials in Examples 1 to 7 are shown in Table 1.

[0060] Table 1 Examples 1 to 7 Medium and low hardness polyurethane 3D heart model printing materials

[0061]

[0062] The above-mentioned low-hardness polyurethane 3D heart model printing material can be prepared by the following preparation method:

[0063] S1. Weigh the components according to the formula, mix the acrylic modified polyurethane and the compatibilizer, and then add the antioxidant and mix well to form a premix;

[0064] S2. Add the premix and thermoplastic polyurethane described in S1 to a twin-screw extruder, melt-extrude and granulate to obtain a low-hardness polyurethane 3D heart model printing material;

[0065] The aspect ratio of the twin-screw extruder is 40:1, and the melt extrusion conditions of the twin-screw extruder are: the temperature of zone 1 is 150°C, the temperature of zone 2 is 180°C, the temperatures of zones 3 to 10 are all 190°C, and the main engine speed is 100-400r / min.

[0066] The heart model can be obtained by the following preparation method: first, the low-hardness polyurethane 3D heart model printing material is dried in a vacuum drying oven at 80°C for 48 hours, and then a 3D printing wire is prepared by a 3D wire testing machine, wherein the screw temperature is set to 190°C and the rotation speed is 30rpm to obtain a 3D printing wire with a diameter of 1.75±0.05mm, and then the prepared 3D printing wire is used to print the heart model by a fused deposition 3D printer, and the printing temperature is 210°C.

[0067] Comparative Examples 1 to 7

[0068] The weight proportions of the components in the low hardness polyurethane 3D heart model printing materials in Comparative Examples 1 to 7 are shown in Table 3.

[0069] Table 2 Comparative Examples 1 to 7 Low and Medium Hardness Polyurethane 3D Heart Model Printing Materials

[0070]

[0071] The above-mentioned low-hardness polyurethane 3D heart model printing material can be prepared by the following preparation method:

[0072] S1. Weigh the components according to the formula, mix the acrylic modified polyurethane and the compatibilizer, and then add the antioxidant and mix well to form a premix;

[0073] S2. Add the premix and thermoplastic polyurethane described in S1 to a twin-screw extruder, melt-extrude and granulate to obtain a low-hardness polyurethane 3D heart model printing material;

[0074] The aspect ratio of the twin-screw extruder is 40:1, and the melt extrusion conditions of the twin-screw extruder are: the temperature of zone 1 is 150°C, the temperature of zone 2 is 180°C, the temperatures of zones 3 to 10 are all 190°C, and the main engine speed is 100-400r / min.

[0075] The heart model can be obtained by the following preparation method: first, the low-hardness polyurethane 3D heart model printing material is dried in a vacuum drying oven at 80°C for 48 hours, and then a 3D printing wire is prepared by a 3D wire testing machine, wherein the screw temperature is set to 190°C and the rotation speed is 30rpm to obtain a 3D printing wire with a diameter of 1.75±0.05mm, and then the prepared 3D printing wire is used to print the heart model by a fused deposition 3D printer, and the printing temperature is 210°C.

[0076] The performance test results of the low hardness polyurethane 3D heart model printing materials in each embodiment and comparative example according to the above-mentioned method are shown in Table 3.

[0077] Table 3 Test results of various embodiments and comparative examples

[0078]

[0079]

[0080] It can be seen from Examples 1 to 7 that the transmittance of the low-hardness polyurethane 3D heart model printing material of the present invention is maintained at more than 87%, and the 3D printing performance is excellent, there is no precipitation, and the yellowing resistance reaches level 4 or above; while it can be seen from Comparative Examples 1 to 7 that when the content of acrylic modified polyurethane is too low or too high, the printing performance deteriorates, when the content of the compatibilizer is less or not added, surface precipitation occurs and the transmittance decreases, when the amount of antioxidant is reduced, the yellowing resistance deteriorates, and the yellowing is serious when the antioxidant is added.

[0081] The above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A low-hardness polyurethane 3D heart model printing material, characterized in that: By weight, it includes the following components: The hardness of the thermoplastic polyurethane is 60A-65A; At 25° C., the viscosity of the acrylic modified polyurethane is 3000 to 30000 CPS; The compatibilizer is polypropylene glycol diglycidyl ether, and the antioxidant is polycarbodiimide; The epoxy groups in the compatibilizer react with the acrylic acid in the acrylic modified polyurethane.

2. The low-hardness polyurethane 3D heart model printing material as claimed in claim 1, characterized in that: The thermoplastic polyurethane adopts GB / T 2410-2008 standard, and its mass melt flow rate is measured at 190° C. and 3.8 kg to be 30-50 g / 10 min.

3. The low-hardness polyurethane 3D heart model printing material as claimed in claim 2, characterized in that: The thermoplastic polyurethane adopts GB / T 2410-2008 standard, and its mass melt flow rate is measured at 190° C. and 3.8 kg to be 40 g / 10 min.

4. The low-hardness polyurethane 3D heart model printing material as claimed in claim 1, characterized in that: The number average molecular weight of the polypropylene glycol diglycidyl ether is 360-400.

5. A method for preparing the low-hardness polyurethane 3D heart model printing material according to any one of claims 1 to 4, characterized in that: The following steps are involved: Thermoplastic polyurethane, acrylic modified polyurethane, a compatibilizer and an antioxidant are uniformly mixed, melt-extruded and granulated to obtain a low-hardness polyurethane 3D heart model printing material.

6. The method for preparing the low-hardness polyurethane 3D heart model printing material as claimed in claim 5, characterized in that: The following steps are involved: S1. The acrylic modified polyurethane and the compatibilizer are mixed evenly, and then an antioxidant is added and mixed evenly to form a premix; S2. Add the premix and thermoplastic polyurethane described in S1 to a twin-screw extruder, melt-extrude and granulate to obtain a low-hardness polyurethane 3D heart model printing material; Wherein, the aspect ratio of the twin-screw extruder is ≥40:1, the extrusion temperature is 150-190° C., and the rotation speed is 100-400 rpm.

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