WO2019085522A1

WO2019085522A1 - Polylactic acid 3d printing material and wire prepared therefrom

Info

Publication number: WO2019085522A1
Application number: PCT/CN2018/092799
Authority: WO
Inventors: 熊凯; 袁志敏; 蔡彤旻; 黄险波; 曾祥斌; 焦建; 卢昌利; 杨晖; 麦开锦; 董学腾
Original assignee: 金发科技股份有限公司; 珠海万通化工有限公司; 上海金发科技发展有限公司
Priority date: 2017-11-03
Filing date: 2018-06-26
Publication date: 2019-05-09
Also published as: CN107974062A; CN107974062B

Abstract

A polylactic acid 3D printing material and a wire prepared therefrom. The polylactic acid 3D printing material comprises the following components: (a) 98.0-100 parts of polylactic acid; and (b) 0-2.0 parts of a processing aid, the number average molecular weight Mn of the polylactic acid being 50,000-150,000 on the basis of the total weight of the entire polylactic acid. The structure of the polylactic acid 3D printing material satisfies the following relationship: 0.8 ≤ Mx / Dx ≤ 7, where Dx represents a polydispersity coefficient defined as Mw / Mn, where Mw is the weight average molecular weight of the polylactic acid 3D printing material, Mn is the number average molecular weight of the polylactic acid 3D printing material, and Mx represents a melt flow rate of the polylactic acid 3D printing material at a temperature of 190°C under a load of 2.16 kg. When the structure satisfies the above relationship, the polylactic acid 3D printing material has a wire diameter range of ≤ 0.12 cm and a wire diameter relative deviation of < 5% when a pulling extrusion speed is 45 Kg/h and an extruded wire diameter is 1.75 cm, thereby exhibiting excellent wire extrusion stability.

Description

Polylactic acid 3D printing material and wire prepared therefrom

Technical field

The invention belongs to the technical field of polymer materials, and in particular relates to a polylactic acid 3D printing material and a wire prepared therefrom.

Background technique

The starch-rich corn can be produced by modern biotechnology to produce a colorless and transparent liquid-lactic acid, which is then subjected to a special polymerization process to form a granular polymer material, polylactic acid (PLA). PLA has the best tensile strength and elongation and can be produced by various common processing methods, such as: melt extrusion, injection molding, blown film forming, foam molding and vacuum forming. In addition, because PLA has good biodegradability, PLA plastic can be used in 3D printing materials, but at this stage, PLA is also limited as a general-purpose plastic, especially 3D printing consumable substrate. Mainly due to the serious brittleness of polylactic acid, the notched impact strength is less than 3KJ/m ² , which severely limits its wide application. Therefore, how to improve the toughness of polylactic acid without affecting its extrusion stability is a problem that must be solved in expanding the application of polylactic acid in 3D printing consumables.

Patent application No.: 201510069937.9 discloses a 3D printing PLA consumable and a preparation method thereof, which are made of the following raw materials by weight: PLA plastic 99.3-99.7%, pigment 0.1-0.3%, auxiliary agent 0.2-0.4 %, but not mentioned for wire extrusion stability.

The invention further finds that when the structure of the polylactic acid 3D printing material satisfies the following relationship: 0.8≤Mx/Dx≤7, the extrusion speed of the polylactic acid 3D printing material is 45Kg/h, and the wire diameter of the extruded wire When it is 1.75cm, the wire diameter difference is ≤0.12cm, and the wire diameter deviation is <5%, which shows better wire extrusion stability.

Summary of the invention

A primary object of the present invention is to provide a polylactic acid 3D printing material having significantly improved extrusion stability.

Another object of the present invention is to provide a wire material prepared from the above polylactic acid 3D printing material.

The invention is achieved by the following technical solutions:

A polylactic acid 3D printing material, in parts by weight, comprising the following components:

(a) Polylactic acid 98.0-100 parts;

(b) Processing aid 0 to 2.0 parts;

Wherein, the number average molecular weight Mn of the polylactic acid is 50,000 to 150,000;

The structure of the polylactic acid 3D printed material satisfies the following relationship:

0.8≤Mx/Dx≤7,

Wherein Dx represents a polydispersity coefficient, defined as Mw/Mn, wherein Mw is the weight average molecular weight of the polylactic acid 3D printing material, Mn is the number average molecular weight of the polylactic acid 3D printing material, and Mx represents the polylactic acid 3D printing material at 190 ° C, The melt flow rate under a load of 2.16 kg was measured according to the ISO 1133 standard.

Wherein, the method for testing the weight average molecular weight Mw and the number average molecular weight Mn of the polylactic acid 3D printing material is: using a Waters 2410 gel permeation chromatograph of Waters Corporation of the United States, the column temperature is 25 ° C, tetrahydrofuran is a solvent and a leaching phase. The flow rate was 1.0 ml/min and the retention time was 50 min. The polystyrene standards with different molecular weights were used as calibration curves.

Mx/Dx refers to the ratio of the melt flow rate of the molecular structure to the polydispersity coefficient, which actually reflects the processing window width and extrusion stability of the polylactic acid 3D printing material, and there are many factors affecting the ratio of Mx/Dx. For example, the microstructure of the raw material polylactic acid is different, and it is well known to those skilled in the art that the polylactic acid can be directly polycondensed by L-lactic acid, D-lactic acid monomer or by ring-opening polymerization of lactide, and the L-lactic acid is adjusted during the synthesis. The content of D-lactic acid monomer, or by controlling the amount of catalyst added, adjusting the degree of vacuum and the reaction time, also affects the molecular weight of the synthesized polylactic acid and the molecular chain sequence structure, thereby making the microstructure of polylactic acid different. In addition, the addition of the auxiliary components and the preparation process (such as different process parameters) and other factors will affect the molecular structure of the final prepared polylactic acid 3D printed material, which leads to its Mx/Dx There is a significant difference in the ratio.

The invention finds that when the structure of the polylactic acid 3D printing material satisfies the following relationship: 0.8≤Mx/Dx≤7, when the drawing speed of the drawing wire is 45Kg/h, and the wire diameter of the extruded wire is 1.75cm, the wire line The diameter difference is ≤0.12cm, and the relative deviation of the wire diameter is <5%, thereby exhibiting good extrusion stability.

Preferably, the structure of the polylactic acid 3D printing material satisfies the following relationship:

1.2≤Mx/Dx≤6,

More preferably, the structure of the polylactic acid 3D printing material satisfies the following relationship:

1.5≤Mx/Dx≤5,

Preferably, the polylactic acid has a number average molecular weight Mn of from 60,000 to 130,000. If the molecular weight is too low, the wire diameter stability during extrusion processing is deteriorated.

The processing aid is selected from the group consisting of a hard ester amide, an oleic acid amide, an erucamide, a zinc stearate, a polymer complex ester of a metal soap, an ethylene bis stearamide, a polyethylene wax, and a silicone lubricant. One or a mixture of two or more.

The present invention also provides a polylactic acid 3D printing wire which is prepared from the above polylactic acid 3D printing material.

Compared with the prior art, the invention has the following beneficial effects:

The invention finds that when the structure of the polylactic acid 3D printing material satisfies the following relationship: 0.8≤Mx/Dx≤7, the extrusion speed of the polylactic acid 3D printing material is 45Kg/h, and the wire diameter of the extruded wire is At 1.75cm, the wire diameter difference is ≤0.12cm, and the wire diameter deviation is <5%, which shows good wire extrusion stability.

Detailed ways

The invention is further illustrated by the following detailed description of the preferred embodiments of the invention, but the embodiments of the invention are not limited by the following examples.

The raw materials used in the present invention are as follows:

Polylactic acid (PLA1): homemade, the number average molecular weight Mn is 90,000;

Polylactic acid (PLA2): homemade, the number average molecular weight Mn is 55000;

Polylactic acid (PLA3): homemade, the number average molecular weight Mn is 40,000;

Processing aids: polymer complex esters of metal soap, ethylene bis stearamide, and silicone masterbatch are all derived from commercially available products.

The preparation method of polylactic acid is as follows:

Add L-lactic acid, D-lactic acid monomer and ZnO in the ratio of Table 1 to the reaction vessel, stir evenly, react at a temperature of 80-140 ° C and a pressure of 4-10 KPa for 6-12 h, and distill off water to form an oligomer. . The reaction product is added to a ZSM-5 molecular sieve in a vacuum distillation reaction vessel, stirred uniformly, and distilled under reduced pressure at 170-210 ° C and a pressure of 102-103 Pa until no product is distilled off for 7-15 hours to obtain lactide. product.

Table 1 Composition ratio of reactant raw materials

A certain amount of the lactide product prepared in Table 1 was accurately weighed into a sealed tube, and a certain amount of a solution of stannous isooctanoate in methylene chloride was added thereto, and the solvent dichloromethane was distilled off at room temperature. The tube was placed at room temperature, evacuated, and high purity nitrogen was injected and repeated three times. After evacuating for half an hour under a certain degree of vacuum, the polymerization tube was vacuum-sealed. After the polymerization tube is sealed, the monomer is first melted, shaken vigorously, the monomer is mixed with the catalyst, and polymerization is carried out at a given temperature. After a certain period of reaction, the sealed tube was taken out, cooled to room temperature, and the sealed tube was broken to obtain a polymer solid. The polymer solid was dissolved under reflux with 5% (w/w) chloroform, and the solution was filtered, and then precipitated with 5 times the volume of chloroform in methanol to obtain a white floc. After suction filtration, the product was vacuum dried at 70 ° C until use. The composition of the raw material of the polylactic acid preparation reactant is as shown in Table 2.

Table 2 Composition ratio of reactant raw materials

Example 1-6: Preparation of polylactic acid 3D printing material

The PLA and the processing aid are uniformly mixed according to the parts by weight shown in Table 3, and then put into a twin-screw extruder, extruded at 160 ° C - 180 ° C, and granulated to obtain a polylactic acid 3D printing material;

The polylactic acid 3D printing material is drawn on a single-screw extruder, the single-screw extrusion temperature is controlled from 160 ° C to 210 ° C, and the temperature of the control water tank is between 40 ° C and 60 ° C, thereby obtaining a polylactic acid 3D printing wire material, wherein The wire diameter of the extruded wire was 1.75 cm, and the extrusion speed of the wire was 45 Kg/h. The performance test results are shown in Table 1.

Comparative Example 1: The number average molecular weight Mn of polylactic acid was 40,000, and the rest was the same as in Example 2.

Performance test method:

Mw is the weight average molecular weight of the polylactic acid 3D printing material, and Mn is the number average molecular weight of the polylactic acid 3D printing material: analyzed by Waters 2410 gel permeation chromatograph of Waters, USA, column temperature 25 ° C, tetrahydrofuran as solvent and leaching phase The flow rate was 1.0 ml/min and the retention time was 50 min. The polystyrene standards with different molecular weights were used as calibration curves.

Mx represents the melt flow rate of the polylactic acid 3D printed material at 190 ° C under a load of 2.16 kg, measured according to the ISO 1133 standard.

Test method for extremely poor wire diameter: Tested with vernier caliper, the wire diameter difference is the difference between the maximum value and the minimum value of a set of measured values; the larger the wire diameter extreme difference, the worse the extrusion stability of the wire;

Relative deviation of wire diameter: The relative deviation of wire diameter refers to the percentage of absolute deviation of a certain measurement as the average value. The absolute deviation refers to the difference between the measured value and the average value. The larger the relative deviation of the wire diameter, the extrusion stability of the wire. The worse.

Table 3 Performance test results of Examples 1-6 and Comparative Example 1

It can be seen from Table 3 from Examples 1-6 and Comparative Example 1 that when the structure of the polylactic acid 3D printing material satisfies the following relationship: 0.8 ≤ Mx / Dx ≤ 7, the polylactic acid 3D printing material is extruded in a wire When the speed is 45Kg/h and the wire diameter of the extruded wire is 1.75cm, the wire diameter difference is ≤0.12cm, and the wire diameter deviation is <5%, which shows good wire extrusion stability; in Comparative Example 1, The wire diameter difference is >0.12cm, the wire diameter deviation is more than 5%, and the wire extrusion stability is poor.

Claims

A polylactic acid 3D printing material characterized by comprising the following components in parts by weight:

(a) Polylactic acid 98.0-100 parts;

(b) Processing aid 0 to 2.0 parts;

Wherein, the number average molecular weight Mn of the polylactic acid is 50,000 to 150,000;

The structure of the polylactic acid 3D printed material satisfies the following relationship:

0.8≤Mx/Dx≤7,

Wherein Dx represents a polydispersity coefficient, defined as Mw/Mn, wherein Mw is the weight average molecular weight of the polylactic acid 3D printing material, Mn is the number average molecular weight of the polylactic acid 3D printing material, and Mx represents the polylactic acid 3D printing material at 190 ° C, The melt flow rate under a load of 2.16 kg was measured according to the ISO 1133 standard.
A polylactic acid 3D printing material according to claim 1, wherein the structure of the polylactic acid 3D printing material satisfies the following relationship:

1.2≤Mx/Dx≤6,

Preferably, the structure of the polylactic acid 3D printing material satisfies the following relationship:

1.5≤Mx/Dx≤5,

Wherein Dx represents a polydispersity coefficient, defined as Mw/Mn, wherein Mw is the weight average molecular weight of the polylactic acid 3D printing material, Mn is the number average molecular weight of the polylactic acid 3D printing material, and Mx represents the polylactic acid 3D printing material at 190 ° C, Melt flow rate under 2.16 kg load conditions.
The polylactic acid 3D printing material according to claim 1 or 2, wherein the weight average molecular weight Mw and the number average molecular weight Mn of the lactic acid 3D printing material are tested by using Waters 2410 of Waters Corporation of the United States. Analysis by gel permeation chromatography, column temperature 25 ° C, tetrahydrofuran as solvent and elution phase, flow rate 1.0 ml / min, retention time 50 min, polystyrene standards with different molecular weights as calibration curve.
The polylactic acid 3D printing material according to claim 1 or 2, wherein the polylactic acid has a number average molecular weight Mn of 60,000 to 130,000.
The polylactic acid 3D printing material according to claim 1 or 2, wherein the processing aid is selected from the group consisting of a hard ester amide, an oleic acid amide, an erucamide, a zinc stearate, and a metal soap. One or a mixture of two or more of a complex ester, an ethylene bis stearamide, a polyethylene wax, and a silicone lubricant.
The polylactic acid 3D printing material according to claim 1 or 2, wherein the polylactic acid 3D printing material has a wire drawing speed of 45 kg/h and an extruded wire diameter of 1.75 cm. The diameter difference is ≤0.12cm, and the relative deviation of the wire diameter is <5%.
A polylactic acid 3D printing wire obtained by the polylactic acid 3D printing material according to any one of claims 1 to 6.