阅读说明：本技术 一种3d打印硅橡胶及其制备方法和应用 (3D printing silicone rubber and preparation method and application thereof ) 是由 夏和生 孙劭杰 王占华 王金志 于 2020-07-16 设计创作，主要内容包括：本发明属于新材料技术领域,提供一种3D打印硅橡胶及其制备方法和应用,3D打印硅橡胶主要包括氨基或羟基封端的聚二甲基硅氧烷、二异氰酸酯、氨基吡唑化合物、交联剂及溶剂,3D打印硅橡胶的制备方法为：将氨基或羟基封端的聚二甲基硅氧烷、二异氰酸酯、氨基吡唑化合物及交联剂按一定的物质的量份数溶解于溶剂中搅拌反应得到预聚物,反应结束后,将预聚物加入模具中,加热固化、除溶剂后得到3D打印硅橡胶材料。本发明的硅橡胶机械强度好,热塑性好,适用于墨水直写(DIW)、熔丝制造(FFF)、选择性激光烧结(SLS)、喷墨3D打印(3DP)等多种3D打印加工方式打印产品无毒无害,具有自修复功能,应用于柔性电子、生物医用等领域。(The invention belongs to the technical field of new materials, and provides 3D printing silicone rubber and a preparation method and application thereof, wherein the 3D printing silicone rubber mainly comprises amino or hydroxyl terminated polydimethylsiloxane, diisocyanate, an aminopyrazole compound, a cross-linking agent and a solvent, and the preparation method of the 3D printing silicone rubber comprises the following steps: dissolving amino or hydroxyl-terminated polydimethylsiloxane, diisocyanate, an aminopyrazole compound and a crosslinking agent in a solvent according to a certain mass part, stirring and reacting to obtain a prepolymer, adding the prepolymer into a mold after the reaction is finished, heating and curing, and removing the solvent to obtain the 3D printing silicone rubber material. The silicone rubber disclosed by the invention is good in mechanical strength and thermoplasticity, is suitable for printing products in various 3D printing and processing modes such as ink direct writing (DIW), fuse manufacturing (FFF), Selective Laser Sintering (SLS), ink-jet 3D printing (3DP) and the like, is non-toxic and harmless, has a self-repairing function, and is applied to the fields of flexible electronics, biomedicine and the like.)

1. The 3D printing silicone rubber is characterized by comprising the following raw materials in parts by weight:

2. the 3D printing silicone rubber according to claim 1, wherein: the amino-terminated or hydroxyl-terminated polydimethylsiloxane is at least one of amino-terminated or hydroxyl-terminated polydimethylsiloxane with the molecular weight of 300-50000.

3. The 3D printing silicone rubber according to claim 1, wherein: the diisocyanate is at least one of toluene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate or dicyclohexylmethane diisocyanate.

4. The 3D printing silicone rubber according to claim 1, wherein: the aminopyrazole compound is 3-aminopyrazole, 2H-3-aminopyrazole, 3-amino-5-pyrazolol, 3, 5-diaminopyrazole, 3- (4-aminobenzene) -5-aminopyrazole, 5-amino-1H-pyrazole-4-carboxylic acid ethyl ester, 3-amino-4-cyanopyrazole, 3-amino-5-hydroxypyrazole, 3-amino-5-methylpyrazole, 5-amino-1H-pyrazole-3-acetic acid, 3-phenyl-1H-pyrazole-5-amine, 3- (3-bromophenyl) -5-aminopyrazole, 4-aminopyrazolo [3,4-d ] pyrimidine, pyridine, 3-amino-5-tert-butylpyrazole, 3-aminopyrazole-4-carboxylic acid methyl ester, 3-aminopyrazole-4-carboxamide, 5-amino-3- (4-bromophenyl) -1H-pyrazole, or 4-aminopyrazole-5-carboxylic acid ethyl ester.

5. The 3D printing silicone rubber according to claim 1, wherein: the crosslinking agent is at least one of hexamethylene diisocyanate trimer, toluene diisocyanate trimer or isophorone diisocyanate trimer.

6. The 3D printing silicone rubber according to claim 1, wherein: the solvent is at least one of toluene, xylene, dichloromethane, chloroform, tetrahydrofuran or 1, 4-dioxane.

7. A method for preparing 3D printing silicone rubber according to any one of claims 1 to 6, wherein: the method mainly comprises the following steps:

the method comprises the following steps: weighing raw materials in proportion, dissolving the raw materials in a solvent to obtain a reaction solution, and stirring the reaction solution at room temperature for 2-10 hours to obtain a prepolymer;

step two: pouring the polymer obtained in the step one into a mold, putting the mold into an oven to remove the solvent, continuously curing, and taking out the mold after curing is finished to obtain a 3D printing silicone rubber solid containing the pyrazole urea dynamic bond;

step three: extruding the 3D printing silicon rubber solid obtained in the step two through a double-screw extruder, and cooling the air to obtain 3D printing silicon rubber strands containing pyrazole urea dynamic bonds;

step four: and D, crushing the 3D printing silicon rubber solid obtained in the step two by using a low-temperature crusher to obtain 3D printing silicon rubber powder containing the pyrazole urea dynamic bond.

8. The preparation method of the 3D printing silicone rubber according to claim 7, wherein the preparation method comprises the following steps: in the second step, the mold is a polytetrafluoroethylene mold, the temperature in the oven is 80 ℃, the time for removing the solvent from the prepolymer and continuously curing the prepolymer is 10-96 hours, and the solvent steam of the prepolymer in the process of removing the solvent in the oven is recovered by a solvent recovery machine.

9. The preparation method of the 3D printing silicone rubber according to claim 7, wherein the preparation method comprises the following steps: in the third step, the extrusion temperature of the 3D printing silicone rubber solid in the double-screw extruder is 120-180 ℃.

10. The application of the 3D printing silicone rubber prepared by the preparation method of the 3D printing silicone rubber according to claim 7, wherein the preparation method comprises the following steps: the 3D printing silicone rubber solid containing the pyrazole urea dynamic key is applied to melt 3D printing technologies such as heating ink direct writing, the 3D printing silicone rubber strand containing the pyrazole urea dynamic key is applied to strand 3D printing technologies such as fuse manufacturing, the 3D printing silicone rubber powder containing the pyrazole urea dynamic key is applied to powder 3D printing technologies such as selective laser sintering and inkjet 3D printing, and the printing product is applied to the fields of flexible electronics, biomedicine and the like.

Technical Field

The invention belongs to the technical field of new materials, and relates to 3D printing silicone rubber, and a preparation method and application thereof.

Background

The polysiloxane main chain is composed of silicon and oxygen atoms alternately, organic groups are directly connected to the silicon atoms, and the polysiloxane has the characteristics of inorganic and organic polymers, such as high and low temperature resistance, weather resistance, electrical insulation, ozone resistance, hydrophobicity, good gas permeability, no toxicity, biological inertia and the like. Is widely applied to the fields of electronics, electrics, buildings, automobiles, textiles, medical treatment and the like. Polysiloxane chains are flexible and have low intermolecular forces, and are therefore generally used in the form of crosslinked elastomers. The traditional silicon rubber product can only be manufactured by an injection molding process, and has the defects of high technical requirement on a mold, high cost, long processing period, low production efficiency, troublesome subsequent maintenance and the like, and can not produce silicon rubber products with precise structures and high precision.

Currently, silicone rubbers that can be used for 3D printing have been reported. Velind et al report a capillary ink 3D printed silicone rubber material. They prepared water with crosslinked polydimethylsiloxane microbeads and liquid non-crosslinked polydimethylsiloxane into multiphase inks. Because the micro beads can be combined through capillary action, the ink is paste, can flow under high shear stress and can be directly extruded and printed, but the mechanical property of the printed product is poor. Short conversation at Guangdong university etc. reported a highly transparent Digital Light Processing (DLP) printed silicone rubber. They use mercapto-olefinic bond reaction to realize the photocuring shaping of materials, and generate ionic interaction to strengthen the materials through carboxyl in the side chain of polydimethylsiloxane precursor and amino at high temperature. However, the strength of the material is only 0.23MPa, which severely restricts the application of the material. Most of 3D printed silicone rubber products reported at present adopt a photocuring forming mechanism, the printing method is single, the mechanical strength of the printed products is not high, and the residual photoinitiator also has potential biological toxicity.

Disclosure of Invention

In view of the above-mentioned disadvantages of the prior art, the present invention provides a 3D printing silicone rubber and a preparation method and application thereof, wherein the pyrazole urea dynamic bond is obtained by reacting pyrazole and isocyanate, and is a novel thermal response type dynamic bond, so that a cross-linked silicone rubber material can be heated and flowed, has thermal processability, and can be used for various 3D printing processing modes such as heating ink direct writing, fuse wire manufacturing, selective laser sintering, ink-jet 3D printing, and the like, and the dynamic bond reaction enhances the interlayer of a self-repairing printed product, reduces the anisotropy of the mechanical strength of the product, enables the printed product to have a self-repairing function, enables the damage of the bonding force of the printed product to be completely repaired at 120 ℃, and improves the mechanical strength of the material, and the silicone rubber has excellent mechanical properties, the printing ink is suitable for various 3D printing modes, has a self-repairing function, and is simple in preparation process and relatively low in cost.

In order to achieve the above and other related objects, the invention provides a 3D printing silicone rubber, which comprises the following raw materials in parts by weight:

preferably, the amino-terminated or hydroxyl-terminated polydimethylsiloxane is at least one of amino-terminated or hydroxyl-terminated polydimethylsiloxanes with molecular weights of 300-50000.

Preferably, the diisocyanate is at least one of toluene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, or dicyclohexylmethane diisocyanate.

Preferably, the aminopyrazole compound is 3-aminopyrazole, 2H-3-aminopyrazole, 3-amino-5-pyrazolol, 3, 5-diaminopyrazole, 3- (4-aminobenzene) -5-aminopyrazole, ethyl 5-amino-1H-pyrazole-4-carboxylate, 3-amino-4-cyanopyrazole, 3-amino-5-hydroxypyrazole, 3-amino-5-methylpyrazole, 5-amino-1H-pyrazole-3-acetic acid, 3-phenyl-1H-pyrazol-5-amine, 3- (3-bromophenyl) -5-aminopyrazole, 4-aminopyrazolo [3,4-d ] pyrimidine, 3-amino-5-tert-butylpyrazole, 3-aminopyrazole-4-carboxylic acid methyl ester, 3-aminopyrazole-4-carboxamide, 5-amino-3- (4-bromophenyl) -1H-pyrazole, or 4-aminopyrazole-5-carboxylic acid ethyl ester.

Preferably, the crosslinking agent is at least one of hexamethylene diisocyanate trimer, toluene diisocyanate trimer or isophorone diisocyanate trimer.

Preferably, the solvent is at least one of toluene, xylene, dichloromethane, chloroform, tetrahydrofuran or 1, 4-dioxane.

A preparation method of 3D printing silicone rubber mainly comprises the following steps:

the method comprises the following steps: weighing raw materials in proportion, dissolving the raw materials in a solvent to obtain a reaction solution, and stirring the reaction solution at room temperature for 2-10 hours to obtain a prepolymer;

step two: pouring the polymer obtained in the step one into a mold, putting the mold into an oven to remove the solvent, continuously curing, and taking out the mold after curing is finished to obtain a 3D printing silicone rubber solid containing the pyrazole urea dynamic bond;

step three: extruding the 3D printing silicon rubber solid obtained in the step two through a double-screw extruder, and cooling the air to obtain 3D printing silicon rubber strands containing pyrazole urea dynamic bonds;

step four: and D, crushing the 3D printing silicon rubber solid obtained in the step two by using a low-temperature crusher to obtain 3D printing silicon rubber powder containing the pyrazole urea dynamic bond.

Preferably, in the second step, the mold is a polytetrafluoroethylene mold, the temperature in the oven is 80 ℃, the time for removing the solvent from the prepolymer and continuously curing the prepolymer is 10-96 hours, and the solvent vapor of the prepolymer in the process of removing the solvent in the oven is recovered by a solvent recovery machine.

Preferably, in the third step, the extrusion temperature of the 3D printing silicone rubber solid in the double-screw extruder is 120-180 ℃.

The 3D printing silicone rubber solid containing the pyrazole urea dynamic key is applied to a 3D printing technology of melts such as heating ink direct writing, the 3D printing silicone rubber strand containing the pyrazole urea dynamic key is applied to a 3D printing technology of strand wires such as fuse wire manufacturing, the 3D printing silicone rubber powder containing the pyrazole urea dynamic key is applied to a 3D printing technology of powder such as selective laser sintering and ink-jet 3D printing, and the printing product is applied to the fields of flexible electronics, biomedicine and the like.

As described above, the 3D printing silicone rubber, and the preparation method and the application thereof of the invention have the following beneficial effects:

1. in the invention, the amino pyrazole compound in the raw materials enables the molecular weight main chain to be provided with the polyurea chain segment, so that the mechanical strength of the material can be obviously improved, and the tensile strength can reach 7 MPa.

2. According to the invention, the pyrazole urea bond in the 3D printing silicone rubber containing the pyrazole urea dynamic bond is a thermally reversible chemical bond, and can be broken at high temperature, and can be regenerated after the temperature is reduced, so that the prepared cross-linked silicone rubber has a processable property, is suitable for various 3D printing processing modes, and can be applied to the fields of flexible electronics, biomedicine and the like.

3. According to the invention, the 3D printing silicone rubber containing the pyrazole urea dynamic bond has self-repairability, and the 3D printing product can realize damage repair without any additional repairing agent or catalyst.

4. In the invention, the used raw materials are easy to obtain, the synthesis process is simple and easy to control, and the yield is high.

Drawings

Fig. 1 is a chemical structure of 3D printing silicone rubber containing a pyrazolea dynamic bond prepared in experimental example 2;

FIG. 2 is an infrared spectrum of 3D printed silicone rubber containing a pyrazolea dynamic bond prepared in test example 2;

FIG. 3 is a drawing of a 3D printed silicone rubber solid containing pyrazole urea dynamic bonds in test example 2;

FIG. 4 is a Scanning Electron Microscope (SEM) image of 3D printed silicone rubber powder containing pyrazolea dynamic bonds in test example 2;

FIG. 5 is a drawing of a 3D printed silicone rubber tensile bar containing a pyrazole urea dynamic bond in test example 4;

FIG. 6 is a drawing of a 3D printed silicone rubber orthopedic insole containing a pyrazolea dynamic bond in test example 4;

FIG. 7 is a stress-strain curve graph before and after damage repair of 3D printed silicone rubber printed tensile sample strips containing pyrazolea dynamic bonds in test example 5;

FIG. 8 is a real object diagram before and after repairing damage of a 3D printed silicon rubber printed insole containing a pyrazole urea dynamic key in test example 5;

FIG. 9 is a schematic view of solid particles of silicone rubber containing pyrazolea dynamic bonds in test example 3;

FIG. 10 is a schematic view of non-dynamic comparative silicone rubber solid particles containing a general urea bond in test example 3;

fig. 11 is a schematic view of solid silicone rubber particles containing a pyrazole urea dynamic bond in test example 3 after hot press molding;

FIG. 12 is a schematic view of non-dynamic comparative silicone rubber solid particles containing a general urea bond in test example 3 after hot press molding.

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.