阅读说明：本技术 一种用于选择性激光烧结的热塑性聚酰胺弹性体粉末及其制备方法 (Thermoplastic polyamide elastomer powder for selective laser sintering and preparation method thereof ) 是由 付鹏 汪纪强 李震 刘民英 赵清香 崔喆 张晓朦 庞新厂 于 2021-08-19 设计创作，主要内容包括：本发明提供了一种用于选择性激光烧结的热塑性聚酰胺弹性体粉末及其制备方法。该弹性体是由不同种类和/或不同的分子量的聚酰胺与聚醚和/或聚酯通过缩合聚合而成。其制备方法包括：1)将热塑性聚酰胺弹性体粒料利用液氮降温预冷,通过冷冻粉碎机机械粉碎,并对粉末筛分,取可用粒度范围≤300μm；2)向筛分后的聚酰胺弹性体粉末中加入助流剂、抗氧化剂,混合,得到可用于选择性激光烧结的聚酰胺弹性体粉末。该系列粉末具有流动性及铺粉性能好、抗静电性强、打印温度窗口宽、不易翘曲变形的优点。本发明制备方法简单易行,适合工业化生产。打印制品精度较高、具有一定的强度和优异的柔韧性。(The invention provides thermoplastic polyamide elastomer powder for selective laser sintering and a preparation method thereof. The elastomer is prepared by condensation polymerization of polyamide with polyether and/or polyester of different types and/or different molecular weights. The preparation method comprises the following steps: 1) cooling and pre-cooling thermoplastic polyamide elastomer granules by using liquid nitrogen, mechanically crushing the granules by using a freezing crusher, and sieving the powder to obtain the available particle size range of less than or equal to 300 mu m; 2) and adding a flow aid and an antioxidant into the sieved polyamide elastomer powder, and mixing to obtain the polyamide elastomer powder for selective laser sintering. The series of powder has the advantages of good fluidity and powder spreading performance, strong antistatic property, wide printing temperature window and difficult warping deformation. The preparation method is simple and feasible, and is suitable for industrial production. The printed product has high precision, certain strength and excellent flexibility.)

1. A thermoplastic polyamide elastomer powder for selective laser sintering, characterized by: the thermoplastic polyamide elastomer is mainly composed of carboxyl-terminated polyamide prepolymer, amino-terminated or hydroxyl-terminated polyether and/or polyester, and the molecular chain repeating unit of the thermoplastic polyamide elastomer has the following structure:

a)

or the following steps:

b)

in the formula, R in a) and b)₁Represents a polyamide segment, R₂、R₃Represents a polyether and/or polyester segment.

2. The thermoplastic polyamide elastomer powder for selective laser sintering according to claim 1, wherein the polyamide prepolymer is one or more of polyamide 6, polyamide 11, polyamide 12, polyamide 610, polyamide 612, polyamide 1010, polyamide 1011, polyamide 1012, polyamide 1013, polyamide 1111, polyamide 1112, polyamide 1113, polyamide 1212, polyamide 1213, polyamide 1313, and polyamide 1414, and has a molecular weight in a range of 500 to 8000.

3. The thermoplastic polyamide elastomer powder for selective laser sintering according to claim 1, wherein the polyether and/or polyester is one or a mixture of two or more of polyethylene glycol, polypropylene glycol, polytetrahydrofuran ether glycol, polytetramethylene glycol, polypentylene glycol, polyhexamethylene adipate 1, 6-hexanediol glycol, polyhexamethylene adipate 1, 4-butanediol glycol, polycarbonate glycol, polyhexamethylene adipate neopentyl glycol-1, 6-hexanediol glycol, polyoxyethylene diamine, polyoxypropylene diamine, double-terminal amino polyethylene oxide propylene oxide copolymer, and polytetramethylene ether diamine, and the molecular weight is 200-5000.

4. A thermoplastic polyamide elastomer filament for fused deposition 3D printing according to claim 1, wherein: the relative viscosity of the thermoplastic polyamide elastomer is 1.5-3.0, and the melt index is 3.0-30.0g/10 min.

5. Process for the preparation of thermoplastic polyamide elastomer powders for the selective laser sintering according to claims 1 to 4, characterized in that it comprises the following steps:

(1) pre-cooling the thermoplastic polyamide elastomer granules for 1-30 min at the temperature of-195 to-80 ℃, mechanically crushing by a freezing crusher, and screening to obtain undersize products with the particle size range of less than or equal to 300 mu m;

(2) and mixing the screened polyamide elastomer powder with a flow aid and an antioxidant in a high-speed mixer according to a certain mass ratio for 5-30 min to obtain the polyamide elastomer powder for selective laser sintering.

6. The method for preparing thermoplastic polyamide elastomer powder for selective laser sintering according to claim 5, wherein liquid nitrogen is used for cooling and pre-cooling in step 1), and the cooling temperature of a freezing pulverizer is-195 ℃ to-80 ℃.

7. The method for preparing thermoplastic polyamide elastomer powder for selective laser sintering according to claim 5, wherein in the step 2), the flow aid is one or a mixture of two or more of fumed nano silicon dioxide, fumed titanium dioxide, talcum powder, calcium stearate, zinc stearate and glass beads, and the addition amount of the flow aid is 0.1-2.0% of the mass of the elastomer powder.

8. The method for preparing the thermoplastic polyamide elastomer powder for selective laser sintering according to claim 7, wherein in the step 2), the antioxidant is one or a mixture of two or more of sodium hypophosphite, antioxidant 1010, antioxidant S9228, antioxidant SH120 and antioxidant B215, and the addition amount of the antioxidant is 0.1-1.0% of the mass of the elastomer powder.

Technical Field

The invention belongs to the technical field of polymer 3D printing materials, and particularly relates to thermoplastic polyamide elastomer powder applicable to selective laser sintering and a preparation method thereof.

Background

Selective Laser Sintering (SLS) is one of typical 3D printing techniques, and its principle is to use high-energy laser to perform programmed selective irradiation and heating on solid powder material, so as to locally melt and finally cool, solidify and form. Compared with other 3D printing technologies, the three-dimensional printing device has the remarkable advantages of high forming precision, capability of forming a complex structure, no need of additional support and the like.

The materials that can be applied to the SLS technique mainly include metal powder materials, film-coated ceramic powder materials, polymer powder materials, and composite materials thereof. According to the physical and chemical properties and the forming structure of different materials, the workpiece can be applied to the fields of aerospace, biomedical treatment, automobile manufacturing, sports devices, mold casting and the like.

The polymer material is an important variety in SLS processing materials, and the polymer material which can be formed by SLS at present can be divided into: non-crystalline polymer powder materials such as polycarbonate Powder (PC), polystyrene Powder (PS), acrylonitrile/butadiene/styrene powder (ABS), polyester Powder (PBT), polyvinyl chloride Powder (PVC); crystalline polymer powder materials such as polyamide Powder (PA) and polyetheretherketone Powder (PEEK); thermoplastic elastomer powder materials such as thermoplastic polyurethane elastomers (TPU), and the like.

Thermoplastic polyamide elastomer (TPAE) is a novel thermoplastic elastomer (TPE) material with wide application prospects, but no research on the application of TPAE in the field of 3D printing exists at present.

Disclosure of Invention

The invention provides thermoplastic polyamide elastomer powder which takes polyamide as a hard segment and polyether and/or polyester as a soft segment, has the toughness and wear resistance of the polyamide and the elasticity and toughness of the polyether/polyester and can be used for selective laser sintering 3D printing, and a preparation method thereof.

In order to realize the purpose, the invention adopts the following technical scheme:

a thermoplastic polyamide elastomer powder for selective laser sintering, said thermoplastic polyamide elastomer consisting essentially of a carboxyl-terminated polyamide prepolymer, an amino-terminated or hydroxyl-terminated polyether and/or polyester, the molecular chain repeat units of which have the following structure:

or the following steps:

in the formula, R in a) and b)₁Represents a polyamide segment, R₂、R₃Represents a polyether and/or polyester segment.

The polyamide prepolymer is one or more of polyamide 6, polyamide 11, polyamide 12, polyamide 610, polyamide 612, polyamide 1010, polyamide 1011, polyamide 1012, polyamide 1013, polyamide 1111, polyamide 1112, polyamide 1113, polyamide 1212, polyamide 1213, polyamide 1313 and polyamide 1414, and has a molecular weight range of 500-8000.

The polyether and/or polyester is one or a mixture of two or more of polyethylene glycol, polypropylene glycol, polytetrahydrofuran ether glycol, polytetramethylene glycol, polypentylene glycol, polyhexamethylene adipate-1, 6-hexanediol glycol, polyhexamethylene adipate-1, 4-butanediol glycol, polycarbonate glycol, polyhexamethylene adipate-neopentyl glycol-1, 6-hexanediol glycol, polyoxyethylene diamine, polyoxypropylene diamine, double-end amino polyethylene oxide propylene oxide copolymer and polytetramethylene ether diamine, and the molecular weight range is 200-5000.

The relative viscosity of the thermoplastic polyamide elastomer is 1.5-3.0, and the melt index is 3.0-30.0g/10 min.

The preparation method of the thermoplastic polyamide elastomer powder for selective laser sintering comprises the following steps:

1) pre-cooling the thermoplastic polyamide elastomer granules for 1-30 min at the temperature of-195 to-80 ℃, mechanically crushing by a freezing crusher, and screening to obtain undersize products with the particle size range of less than or equal to 300 mu m;

2) and mixing the screened polyamide elastomer powder with a flow aid and an antioxidant in a high-speed mixer according to a certain mass ratio for 5-30 min to obtain the polyamide elastomer powder for selective laser sintering.

In the step 1), liquid nitrogen is used for cooling and precooling, and the cooling temperature of a freezing pulverizer is minus 195 to minus 80 ℃.

In the step 2), the flow aid is one or a mixture of two or more of fumed silica, fumed titanium dioxide, talcum powder, calcium stearate, zinc stearate and glass beads, and the addition amount of the flow aid accounts for 0.1-2.0% of the mass of the elastomer powder.

In the step 2), the antioxidant is one or a mixture of two or more of sodium hypophosphite, antioxidant 1010, antioxidant S9228, antioxidant SH120 and antioxidant B215, and the addition amount of the antioxidant accounts for 0.1-1.0% of the mass of the elastomer powder.

The preparation method of the thermoplastic polyamide elastomer comprises the following specific steps:

a) adding dibasic acid, diamine and deionized water into a high-pressure reaction kettle, wherein the using amount ratio of the dibasic acid to the diamine to the deionized water is (1.14-1.50) mol:0.25kg of 1 mol; or adding dibasic acid and caprolactam/laurolactam, wherein the molar ratio of the dibasic acid to the lactam is 1: 2-80; or adding dibasic acid and aminoundecanoic acid, wherein the molar ratio of the dibasic acid to the aminoundecanoic acid is 1: 3-40;

keeping the pressure of the system at the temperature of 190-300 ℃ and the pressure of 1-2MPa for 0.5-1.5h in the inert gas atmosphere, and after the pressure keeping is finished, releasing steam within 1.5-3h to normal pressure and continuing to react for 0.5-1 h; the inert gas is one of nitrogen, argon and carbon dioxide;

b) adding polyester and/or polyether into the kettle, carrying out vacuum reaction for 2.0-5.0h at the temperature of 190-.

The TPAE material is firstly applied to selective laser sintering forming, the powder preparation process of the TPAE material is investigated and optimized, and a series of TPAE powder composite materials suitable for a selective laser sintering technology are developed. The advantages of high SLS printing speed and high forming precision are combined, so that the TPAE has wide application prospects in the fields of medical correction, sports equipment, shoe materials and clothes, aerospace, sensors, drivers and the like. Compared with the prior art, the invention has the following technical advantages:

1. the invention provides novel thermoplastic polyamide elastomer (TPAE) powder for selective laser sintering 3D printing forming, which is formed by copolymerizing polyamide hard segments with certain molecular weight and polyether and/or polyester soft segments. TPAE can regulate and control physical and mechanical properties and melting point of products in a large range through selection of types and molecular weights of soft and hard chain segments, the properties of TPAE have toughness and wear resistance of polyamide and low temperature resistance and flexibility of soft segments, and the rebound rate is more than twice of that of polyurethane materials.

2. The invention discloses a novel method for preparing TPAE selective laser sintering 3D printing powder by a freezing and crushing method. By screening the antioxidant and the flow aid and investigating and optimizing the freezing and crushing process conditions, the single utilization rate of the powder is higher than 60%, and the production cost is greatly reduced. Compared with the traditional solvent precipitation method, the method does not need an organic solvent, further improves the production safety, reduces the three-waste discharge and the raw material cost, and can prepare the selective laser sintering TPAE powder in an environment-friendly and high-efficiency manner by adopting the cryogenic grinding method.

3. The TPAE powder prepared by the invention is a novel polymer material for SLS printing, and a hard segment crystal region forms physical support in an elastomer, so that the dimensional stability of a printed product is improved; the soft segment has lower glass transition temperature and segment flexibility, and endows the copolymer with excellent flexibility. The TPAE powder prepared by the method has physical and mechanical properties equivalent to those of a melt processing printed product, does not need a chain extender, a catalyst and the like in raw materials, is nontoxic, does not contain heavy metal, has good biocompatibility, and can be used in the fields of biology, medical materials, food packaging and the like.

4. Compared with polyurethane 3D printing powder, the TPAE powder has better thermal stability and low temperature resistance and wider adjustable hardness range. The TPAE powder has good antistatic property, has wider usable particle size range (0-300 mu m) in the SLS printing process, high single utilization rate (more than 60 percent) of the powder and good fluidity, and can effectively solve the problems of poor powder laying performance, low size precision, poor fluidity and low powder utilization rate of the powder in the SLS printing process. The large difference in melting point and crystallization temperature between the hard and soft segments allows the TPAE powder to have a wider SLS printing window. When the TPAE powder is close to the melting point of the material, the TPAE powder still can keep good powder fluidity, and does not adhere or agglomerate. Therefore, the preheating temperature of the powder can be close to the melting point, and the laser power required during printing is low. The advantages are high printing speed, no yellowing and no thermal decomposition of the product. Compared with polyurethane powder, the polyurethane powder begins to bond at about 70 ℃, so the preheating temperature is about 60 ℃, the difference between the preheating temperature and the melting point is more than 100 ℃, the required laser power is high, the printing speed is low, high-power laser can cause the powder to be decomposed during printing, and besides smoke, the product performance can be reduced.

Detailed Description

In order that the invention may be more clearly understood, the following description will further illustrate embodiments of the invention, but the scope of the invention is not limited thereto. In the examples of the present invention, the preparation method of the thermoplastic elastomer is as follows:

a) adding dibasic acid, diamine and deionized water into a high-pressure reaction kettle, wherein the using amount ratio of the dibasic acid to the diamine to the deionized water is (1.14-1.50) mol:0.25kg of 1 mol; or adding dibasic acid and caprolactam/laurolactam, wherein the molar ratio of the dibasic acid to the lactam is 1: 2-80; or adding dibasic acid and aminoundecanoic acid, wherein the molar ratio of the dibasic acid to the aminoundecanoic acid is 1: 3-40;

keeping the pressure of the system at the temperature of 190-300 ℃ and the pressure of 1-2MPa for 0.5-1.5h in the inert gas atmosphere, and after the pressure keeping is finished, releasing steam within 1.5-3h to normal pressure and continuing to react for 0.5-1 h; the inert gas may be one of nitrogen, argon and carbon dioxide;

b) adding polyester and/or polyether into the kettle, carrying out vacuum reaction for 2.0-5.0h at the temperature of 190-.

Example 1

In the thermoplastic polyamide elastomer powder for selective laser sintering in the embodiment, the hard segment of the thermoplastic polyamide elastomer is carboxyl-terminated polyamide 1212 (molecular weight of 1000), the soft segment is polyethylene oxide diamine (molecular weight of 1000), the relative viscosity of the elastomer is 1.64, and the melt index is 16.5g/10 min.

The preparation method comprises the following steps:

1) 10kg of elastomer granules are taken to be subjected to deep-cooling crushing, the precooling time is 5min, the precooling temperature is-195 ℃, the crushing temperature is-100 ℃, and the rotating speed frequency of a cutter head is 45 Hz. The pulverized powder was dried at 80 ℃ for 5 hours and tested to a moisture content of less than 0.5%. And screening the dried coarse powder by using an electric vibrating screen machine, wherein the particle size distribution range is 0-200 mu m.

2) 1.0kg of screened elastomer powder, 2.0g of fumed nano silicon dioxide, 5.0g of fumed titanium dioxide and 1.5g of fine sodium hypophosphite powder are mixed by a high-speed mixer for 10min to prepare thermoplastic polyamide elastomer selective laser sintering 3D printing powder with the bulk density of 0.40g/cm³The angle of repose is 38.2 °.

Example 2

In the thermoplastic polyamide elastomer powder for selective laser sintering in the embodiment, the hard segment of the thermoplastic polyamide elastomer is carboxyl-terminated polyamide 1212 (molecular weight of 1000), the soft segment is polypropylene oxide diamine (molecular weight of 2000), the relative viscosity of the elastomer is 1.74, and the melt index is 15.4g/10 min.

The preparation method comprises the following steps:

1) 10kg of elastomer granules are taken to be subjected to deep-cooling crushing, the precooling time is 10min, the precooling temperature is-150 ℃, the crushing temperature is-130 ℃, and the cutter head rotating speed frequency is 45 Hz. The pulverized powder was dried at 80 ℃ for 5 hours and tested to a moisture content of less than 0.5%. And (4) screening the dried coarse powder by using an electric vibrating screen machine, wherein the particle size distribution range is 0-300 mu m.

2) 1.0kg of screened elastomer powder, 1.0g of fumed nano silicon dioxide, 5.0g of fumed titanium dioxide and 1.0g of fine sodium hypophosphite powder are mixed by a high-speed mixer for 5min to prepare thermoplastic polyamide elastomer selective laser sintering 3D printing powder with the bulk density of 0.48g/cm³The angle of repose is 38.8 °.

Example 3

In the thermoplastic polyamide elastomer powder for selective laser sintering in the embodiment, the hard segment of the thermoplastic polyamide elastomer is carboxyl-terminated polyamide 1012 (molecular weight of 5000), the soft segment of the thermoplastic polyamide elastomer is polytetrahydrofuran diamine (molecular weight of 1000), the relative viscosity of the elastomer is 2.31, and the melt index is 5.34g/10 min.

The preparation method comprises the following steps:

1) 10kg of elastomer granules are taken to be subjected to deep-cooling crushing, the precooling time is 20min, the precooling temperature is-100 ℃, the crushing temperature is-100 ℃, and the cutter head rotating speed frequency is 35 Hz. The pulverized powder was dried at 80 ℃ for 5 hours and tested to a moisture content of less than 0.5%. And screening the dried coarse powder by using an electric vibrating screen machine, wherein the particle size distribution range is 0-200 mu m.

2) 1.0kg of screened elastomer powder, 2.0g of fumed nano silicon dioxide, 5.0g of fumed titanium dioxide and 1.5g of fine sodium hypophosphite powder are mixed by a high-speed mixer for 5min to prepare thermoplastic polyamide elastomer selective laser sintering 3D printing powder with the bulk density of 0.43g/cm³The angle of repose is 38.6 °.

Example 4

In the thermoplastic polyamide elastomer powder for selective laser sintering in the embodiment, the hard segment of the thermoplastic polyamide elastomer is carboxyl-terminated polyamide 1111 (molecular weight of 8000), the soft segment is amino-terminated polyethylene oxide propylene oxide copolymer (molecular weight of 2000), the relative viscosity of the elastomer is 3.00, and the melt index is 3.00g/10 min.

The preparation method comprises the following steps:

1) 10kg of elastomer granules are taken to be subjected to deep-cooling crushing, the precooling time is 30min, the precooling temperature is-195 ℃, the crushing temperature is-80 ℃, and the rotating speed frequency of a cutter head is 30 Hz. The pulverized powder was dried at 80 ℃ for 5 hours and tested to a moisture content of less than 0.5%. And screening the dried coarse powder by using an electric vibrating screen machine, wherein the particle size distribution range is 0-200 mu m.

2) 1.0kg of screened elastomer powder, 0.5g of fumed nano silicon dioxide, 0.5g of fumed titanium dioxide and 1.5g of fine sodium hypophosphite powder are mixed by a high-speed mixer for 5min to prepare thermoplastic polyamide elastomer selective laser sintering 3D printing powder with the bulk density of 0.46g/cm³The angle of repose is 40.8 °.

Example 5

In the thermoplastic polyamide elastomer powder for selective laser sintering in the embodiment, the hard segment of the thermoplastic polyamide elastomer is carboxyl-terminated polyamide 1313 (molecular weight is 1000), the soft segment of the thermoplastic polyamide elastomer is polyoxyethylene diamine (molecular weight is 200), the relative viscosity of the elastomer is 1.84, and the melt index is 13.5g/10 min.

The preparation method comprises the following steps:

1) and (2) carrying out deep cooling crushing on 10kg of elastomer granules, wherein the precooling time is 10min, the precooling temperature is minus 80 ℃, the crushing temperature is minus 195 ℃, and the rotating speed frequency of a cutter is 45 Hz. The pulverized powder was dried at 80 ℃ for 5 hours and tested to a moisture content of less than 0.5%. And screening the dried coarse powder by using an electric vibrating screen machine, wherein the particle size distribution range is 0-200 mu m.

2) 1.0kg of screened elastomer powder, 5.0g of fumed nano silicon dioxide, 5.0g of fumed titanium dioxide and 5.0g of fine sodium hypophosphite powder are mixed by a high-speed mixer for 20min to prepare thermoplastic polyamide elastomer selective laser sintering 3D printing powder with the bulk density of 0.49g/cm³The angle of repose was 37.3 °.

Example 6

In the thermoplastic polyamide elastomer powder for selective laser sintering in the embodiment, the hard segment of the thermoplastic polyamide elastomer is double-end carboxyl polyamide 6 (molecular weight is 500), the soft segment is polyethylene glycol (molecular weight is 5000), the relative viscosity of the elastomer is 1.50, and the melt index is 30.0g/10 min.

The preparation method comprises the following steps:

1) 10kg of elastomer granules are taken to be subjected to deep-cooling crushing, the precooling time is 5min, the precooling temperature is-155 ℃, the crushing temperature is-80 ℃, and the cutter head rotating speed frequency is 50 Hz. The pulverized powder was dried at 80 ℃ for 5 hours and tested to a moisture content of less than 0.5%. And (4) screening the dried coarse powder by using an electric vibrating screen machine, wherein the particle size distribution range is 0-300 mu m.

1.0kg of screened elastomer powder, 10.0g of fumed nano silicon dioxide, 10.0g of fumed titanium dioxide and 10.0g of fine sodium hypophosphite powder are mixed by a high-speed mixer for 30min to prepare thermoplastic polyamide elastomer selective laser sintering 3D printing powder with the bulk density of 0.51g/cm³The angle of repose was 36.8 °.

Example 7

In the thermoplastic polyamide elastomer powder for selective laser sintering in the embodiment, the hard segment of the thermoplastic polyamide elastomer is carboxyl-terminated polyamide 66 (molecular weight is 1000), the soft segment of the thermoplastic polyamide elastomer is polytetrahydrofuran diol (molecular weight is 1000), the relative viscosity of the elastomer is 1.82, and the melt index is 10.5g/10 min.

The preparation method comprises the following steps:

1) and (2) carrying out deep cooling crushing on 10kg of elastomer granules, wherein the precooling time is 10min, the precooling temperature is-195 ℃, the crushing temperature is-100 ℃, and the rotating speed frequency of a cutter is 45 Hz. The pulverized powder was dried at 80 ℃ for 5 hours and tested to a moisture content of less than 0.5%. And screening the dried coarse powder by using an electric vibrating screen machine, wherein the particle size distribution range is 0-200 mu m.

2) 1.0kg of screened elastomer powder, 2.0g of fumed nano silicon dioxide, 2.0g of fumed titanium dioxide and 1.5g of fine sodium hypophosphite powder are mixed by a high-speed mixer for 5min to prepare thermoplastic polyamide elastomer selective laser sintering 3D printing powder with the bulk density of 0.37g/cm³The angle of repose is 40.4 °.

Example 8

A thermoplastic polyamide elastomer powder for selective laser sintering of this example differs from example 1 only in that the hard segment portion used for synthesizing the elastomer molecular chain is carboxyl-terminated polyamide 12. The relative viscosity of the elastomer was 1.61 and the melt index was 19.5g/10 min.

The bulk density of the composite elastomer powder obtained after processing was 0.41g/cm3, and the repose angle was 39.6 °.

Example 9

A thermoplastic polyamide elastomer powder for selective laser sintering of this example differs from example 1 only in that the hard segment portion used for synthesizing the elastomer molecular chain is carboxyl-terminated polyamide 1010. The relative viscosity of the elastomer was 1.74 and the melt index was 16.5g/10 min.

The composite elastomer powder obtained after processing had a bulk density of 0.42g/cm3 and a repose angle of 38.7 °.

Example 10

A thermoplastic polyamide elastomer powder for selective laser sintering of the present example differs from example 1 only in that the hard segment portion used for synthesizing the elastomer molecular chain is carboxyl-terminated polyamide 1414. The relative viscosity of the elastomer was 1.76 and the melt index was 13.5g/10 min.

The composite elastomer powder obtained after processing had a bulk density of 0.39g/cm3 and a repose angle of 40.6 °.

Testing of some of the physical Properties of the products of the invention

In the examples of the present invention, some physical properties of the obtained elastomer body and powder were characterized, and the following test instruments and test standards were used for the characterization.

TABLE 1 test items, instruments and standards

The properties of the articles obtained in examples 1 to 10 are as follows.

Table 2 examples one-ten physical and mechanical properties of thermoplastic polyamide elastomer powder obtained in examples

The above examples describe several embodiments of the present invention in more detail and in detail, but do not represent limitations to the scope of the invention. The protection scope of the present patent shall be subject to the appended claims.