CN114456435A

CN114456435A - LED photocuring 3D printing material reinforced by expandable carbon fibers

Info

Publication number: CN114456435A
Application number: CN202210162103.2A
Authority: CN
Inventors: 徐旸; 楼钦
Original assignee: Yiwu Science Polymer Material Co ltd
Current assignee: Yiwu Science Polymer Material Co ltd
Priority date: 2022-02-22
Filing date: 2022-02-22
Publication date: 2022-05-10
Anticipated expiration: 2042-02-22
Also published as: CN114456435B

Abstract

The invention discloses an expandable carbon fiber reinforced LED photocuring 3D printing material which is prepared by mixing the following raw materials: 25-45 wt% of polyurethane acrylate resin, 50-70 wt% of diluent, 1-7 wt% of photoinitiator, 0.03-0.05 wt% of polymerization inhibitor, 0.01-0.04 wt% of expanding agent, 0.01-0.05 wt% of carbon fiber powder and 0.01-0.05 wt% of defoaming agent. The invention can effectively reduce the shrinkage rate without influencing the mechanical property and the ultraviolet transmittance of the cured product.

Description

LED photocuring 3D printing material reinforced by expandable carbon fibers

Technical Field

The invention relates to the technical field of 3D printing material production, in particular to an expandable carbon fiber reinforced LED photocuring 3D printing material.

Background

The 3D printing technology is developed for forty years, and technologies such as computer aided design, material processing and molding technology are integrated. Based on the digital model file, the special metal material, non-metal material and medical biomaterial are stacked layer by layer through software and a numerical control system according to the modes of extrusion, sintering, melting, photocuring, spraying and the like to manufacture the solid object.

The photocuring rapid prototyping technology is one of the most widely used 3D printing technologies at present. The photocuring fast forming technology integrates advanced technologies such as computer aided design, information processing, digital control, laser, precise servo drive, new materials and the like, constructs a three-dimensional model according to three-dimensional modeling software on a computer, performs layered slicing processing on the three-dimensional model to obtain two-dimensional profile data information of each layer of section, selectively cures forming materials through the movement of servo drive curing equipment to form section profile graphs of each layer which are very close to a theoretical profile, and gradually and sequentially superimposes the section profile graphs into three-dimensional solid parts, thereby realizing fast completion of prototypes and parts with any complex shapes.

The expandable material is a material with a porous structure generated by gasification or expansion of an expanding agent in the material, the density and the dosage of the material can be reduced on the premise of less loss of the mechanical property of the material, and the requirements of light weight, high strength and functionality of the material are met. The foaming material has long fatigue life, better toughness, thermal stability, energy absorption and insulation performance, and wide application prospect in the fields of automobiles, household appliances, electronics, buildings, consumer product industry and military affairs.

But the current LED photocuring 3D printing manufactured model is easy to cause shrinkage deformation of a formed model, and the most economical method for reducing the shrinkage rate is as follows: although the chain transfer agent method and the inorganic filler method are effective in reducing the volume shrinkage, the addition content of the filler and the chain transfer agent is usually 10 wt% or more, which affects the mechanical properties and the ultraviolet transmittance of the cured material. CN110240679A discloses a high-performance photocuring 3D printing material and a preparation method thereof, wherein the material is a photocuring resin mainly prepared from a monomer or oligomer of a photocuring resin containing supramolecular groups and a photoinitiator. Mixing the materials except the photo-curable resin monomer or oligomer containing the supramolecular group with a photoinitiator and stirring; the solution was considered to be completely dissolved when a transparent liquid was obtained; and adding a photo-curable resin monomer or oligomer containing a supramolecular group into the mixture obtained in the step, stirring and mixing uniformly, and reacting to obtain a product. This technique still has the problem that the mechanical properties of the cured material are affected.

In addition, CN110862673A discloses a foamed thermoplastic elastomer material for 3D printing and a preparation method thereof, the material comprises a thermoplastic elastomer, a diffusion oil and foamed microspheres having a core-shell structure, and a printed sample prepared from a foamed thermoplastic elastomer wire has excellent properties of light weight, good resilience, low density and the like, but still has the problem of low material molding precision and large shrinkage.

Therefore, the development of an LED photocurable 3D printing resin capable of efficiently reducing the shrinkage rate and improving the mechanical properties of the material is an urgent problem to be solved.

Disclosure of Invention

The invention aims to solve the problems of low molding precision, serious shrinkage deformation and poor mechanical property of the existing LED photocuring 3D printing material, and provides an expandable carbon fiber reinforced LED photocuring 3D printing material which has no problem that the final product performance is influenced by large shrinkage rate, and can effectively reduce the shrinkage rate without influencing the mechanical property and the ultraviolet transmittance of a cured product.

The technical scheme adopted by the invention for solving the technical problems is as follows:

an expandable carbon fiber reinforced LED photocuring 3D printing material is prepared by mixing the following raw materials:

25-45 wt% of polyurethane acrylate resin, 50-70 wt% of diluent, 1-7 wt% of photoinitiator, 0.03-0.05 wt% of polymerization inhibitor, 0.01-0.04 wt% of expanding agent, 0.01-0.05 wt% of carbon fiber powder and 0.01-0.05 wt% of defoaming agent. Preferably, the fineness of the carbon fiber powder is 100-1000 meshes, and the mechanical properties such as hardness of the material are further improved.

Preferably, the urethane acrylate resin is aliphatic urethane acrylate or aromatic urethane acrylate. The aliphatic polyurethane acrylate is preferable, and the adopted aliphatic polyurethane acrylate has higher functionality (3-6), better light stability and lower viscosity than aromatic polyurethane acrylate under the same molecular weight. The molded product also has the advantages of high hardness, high polymerization speed and the like.

Preferably, the polyurethane acrylate resin contains a modifier, and the modifier is an acrylic resin with the relative molecular mass of 20000-35000, and the content of the polyurethane acrylate resin is 75-82% and the content of the acrylic resin is 18-25% in percentage by weight. The glass transition temperature Tg of the acrylic resin is less than 60 ℃, so that the resin has high hardness, good toughness and small shrinkage, and the mixed resin has the property similar to ABS by combining the polyurethane acrylate with the acrylic resin, thereby effectively reducing the shrinkage rate of products and improving the molding precision.

Preferably, the diluent is selected from one or more of monofunctional reactive diluent and difunctional reactive diluent.

Preferably, the diluent is a combination of two or more selected from the group consisting of hydroxy methacrylate, alkyl acrylate, trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate.

Preferably, the photoinitiator is selected from one or two of photoinitiator TPO and photoinitiator 819.

Preferably, the polymerization inhibitor is selected from one or more of hydroquinone and p-methoxyphenol. The polymerization inhibitor prevents cross-linking polymerization of the material during transportation and storage.

Preferably, the expanding agent is selected from one or more of high temperature expandable microspheres 920DU40, high temperature expandable microspheres 909DU80 and high temperature expandable microspheres 093DU 120. The high-temperature expandable microspheres are selected, so that the high-temperature expandable microspheres can be ensured not to be foamed at the temperature in the photocuring 3d printing process, the shrinkage rate of a product can be obviously reduced, the molding precision is improved, and the ultraviolet transmittance and the mechanical property of the product are not influenced. The high-temperature expansion microspheres are used for reducing shrinkage on the basis of ensuring that a complete part can be formed.

Preferably, the swelling agent swells at 180 ℃ at 120 ℃, and the primary particle size is 6-38 microns, and the particle size after swelling is 30-130 microns. The specific 920DU40 initial particle size is 6-18 microns, and the particle size is about 40 microns after expansion; 909DU80 has the initial grain diameter of 18-24 microns and is about 80 microns after expansion; 093DU120 has an initial particle size of 28-38 microns and is about 120 microns after expansion.

Preferably, the defoaming agent is one or more of organosilicon defoaming agent LJ-618, KR-XP96 and mineral oil B-302 defoaming agent. The defoaming agent can quickly remove bubbles generated in the materials during high-speed stirring or bumpy transportation and the like.

Preferably, the preparation method comprises the following steps:

(1) preparing all raw materials according to the proportion;

(2) mixing the polymerization inhibitor, the photoinitiator and the diluent, and stirring for 15-45min at the rotating speed of 500-700r/min by using a dispersion machine until the polymerization inhibitor and the photoinitiator are completely dissolved;

(3) the rotation speed of the dispersion machine is adjusted to 300-; after the mixture is uniformly stirred, the rotating speed is reduced to 350-400r/min, and the defoaming agent is added and stirred for 30-35 min;

(4) after defoaming, slowly adding the polyurethane acrylate resin, and uniformly stirring at the rotating speed of 300-500r/min by using a dispersion machine;

(5) adding carbon fiber powder into the uniformly mixed material liquid obtained in the step (4), and stirring for 15-45min by using a dispersion machine at the rotating speed of 500-700r/min until the carbon fiber powder is uniformly mixed;

(6) putting the proportioned materials into a three-roll grinder to grind for 2-3 times;

(7) and (4) filtering the feed liquid ground in the step (7) by using 100-mesh filter cloth, wherein the filtered feed liquid is the expanded carbon fiber reinforced LED photocuring 3D printing material.

The invention has the beneficial effects that:

1. after the expanded microspheres are added into the feed liquid, the expanded microspheres need to be dispersed and mixed uniformly at a high speed, so that the subsequent expansion of the forming model is ensured to be uniform. In addition, a three-roll grinder is adopted to control the grinding gap for grinding, so that the minimum microsphere particle size is obtained on the basis of not damaging the microsphere structure, and the ultraviolet transmittance is improved.

2. The soft and hard combined acrylic and polyurethane reduce shrinkage to a certain extent, while the high-temperature expandable microspheres of the invention counteract partial shrinkage after printing is finished, and the shrinkage is effectively reduced under the combined action of the acrylic and the polyurethane.

Detailed Description

The technical solution of the present invention will be further specifically described below by way of specific examples.

In the present invention, the raw materials and equipment used are commercially available or commonly used in the art, unless otherwise specified. The methods in the following examples are conventional in the art unless otherwise specified.

The technical solution of the present patent will be described in further detail with reference to the following embodiments.

General description of the embodiments

25-45 wt% of polyurethane acrylate resin, 50-70 wt% of diluent, 1-7 wt% of photoinitiator, 0.03-0.05 wt% of polymerization inhibitor, 0.01-0.04 wt% of expanding agent, 0.01-0.05 wt% of carbon fiber powder and 0.01-0.05 wt% of defoaming agent.

The polyurethane acrylate resin is aliphatic polyurethane acrylate or aromatic polyurethane acrylate. Preferably, the polyurethane acrylate resin contains a modifier, and the modifier is an acrylic resin with the relative molecular mass of 20000-35000, and the content of the polyurethane acrylate resin is 75-82% and the content of the acrylic resin is 18-25% in percentage by weight.

The diluent is selected from one or more of monofunctional reactive diluent and bifunctional reactive diluent. Preferably, the diluent is selected from more than two of hydroxyl methacrylate, alkyl acrylate, trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate.

The photoinitiator is one or two selected from photoinitiator TPO and photoinitiator 819; the polymerization inhibitor is selected from one or two of hydroquinone and p-methoxyphenol.

The expanding agent is selected from one or more of high-temperature expandable microspheres 920DU40, high-temperature expandable microspheres 909DU80 and high-temperature expandable microspheres 093DU 120. The expanding agent expands at the temperature of 120-180 ℃, the initial particle size is 6-38 microns, and the particle size after expansion is 18-62 microns.

The defoaming agent is one or more of organosilicon defoaming agent LJ-618, KR-XP96 and mineral oil B-302 defoaming agent.

The preparation method comprises the following steps:

(1) preparing all raw materials according to the proportion;

Example 1

59.8g of polyurethane acrylate resin, 130g of diluent (70 g of hydroxyl methacrylate, 20g of alkyl acrylate and 40g of trimethylolpropane triacrylate), 10g of photoinitiator (TPO), 10g of expanding agent AKCONOBEL 920 DU400.06g, 0.08g of polymerization inhibitor (hydroquinone), 0.02g of carbon fiber powder (fineness 200 and 300 meshes) and LJ-6180.04g of defoaming agent are prepared according to the proportion.

The acrylic resin with the relative molecular mass of 20000-35000 is added into the polyurethane acrylate resin, and the content of the polyurethane acrylate resin is 80% and the content of the acrylic resin is 20% in percentage by weight.

And mixing the polymerization inhibitor, the photoinitiator and the diluent, and stirring for 30min at the rotating speed of 600r/min by using a dispersion machine until the polymerization inhibitor and the photoinitiator are completely dissolved.

Regulating the rotation speed of a dispersion machine to 350r/min, stirring at a low speed, adding an expanding agent in the low-speed stirring process, and after the addition is finished, stirring at a high speed of 1000r/min for 30min by the dispersion machine; after the mixture is stirred uniformly, the rotating speed is reduced to 380r/min, and the defoaming agent is added and stirred for 35 min.

After defoaming, slowly adding the polyurethane acrylate resin, and uniformly stirring at the rotating speed of 400r/min by using a dispersion machine.

Adding carbon fiber powder into the feed liquid, and stirring for 30min at the rotating speed of 600r/min by using a dispersion machine until the carbon fiber powder is uniformly mixed.

And (3) grinding the proportioned material in a three-roll grinder for 3 times.

And filtering the uniformly mixed feed liquid by using 100-mesh filter cloth, wherein the filtered feed liquid is the expanded carbon fiber reinforced LED photocuring 3D printing material.

And cooling the prepared expanded carbon fiber reinforced LED photocuring 3D printing material to room temperature, and measuring the light transmittance of the liquid resin by using a transmission spectrocolorimeter to obtain the light transmittance.

Pouring the prepared liquid resin into a resin tank of a photocuring 3D printer, and casting a tensile experiment model and a size shrinkage model by using the photocuring 3D printer.

And (3) carrying out a tensile test on the manufactured tensile test model by using a universal electronic testing machine, and measuring the size of the size shrinkage model by using an optical microscope and a screw micrometer.

And (3) putting the formed model into a 100 ℃ oven to be heated for 1h, fully expanding the expanded microspheres, then carrying out size measurement, and calculating the shrinkage rate.

Example 2

Unlike example 1, the swelling agent is AKCONOBEL 909DU 80.

Example 3

Unlike example 1, the swelling agent is AKCONOBEL 093DU 120.

Comparative example 1

The test was performed using urethane acrylate without acryl resin, and the other was the same as in example 1.

Comparative example 2

A comparative test was carried out without adding a carbon fiber reinforcement, and 59.82g of the urethane acrylate resin, 130g of the diluent (70 g of hydroxy methacrylate, 20g of alkyl acrylate, 40g of trimethylolpropane triacrylate), 10g of The Photoinitiator (TPO), 10g of the swelling agent AKCONOBEL 920 DU400.06g of The Photoinitiator (TPO), 0.08g of the polymerization inhibitor (hydroquinone), and 0.8978 g of the defoaming agent LJ-6180.04g were prepared in proportion as described above, and the rest was the same as in example 1.

Comparative example 3

Adopts inorganic expansion material gas phase SiO₂The rest of the procedure was the same as in example 1.

Comparative example 4

The same procedure as in example 1 was repeated except that the expanded beads disclosed in CN110862673A were used as the expanding agent.

Comparative example 5

59.86g of polyurethane acrylate resin, 130g of diluent (70 g of hydroxyl methacrylate, 20g of alkyl acrylate and 40g of trimethylolpropane triacrylate), 10g of photoinitiator (TPO), 0.08g of polymerization inhibitor (hydroquinone), 0.02g of carbon fiber powder (fineness of 200-300 meshes) and LJ-6180.04g of defoaming agent are prepared according to the proportion by adopting a comparison test without adding an expanding agent. The rest is the same as in example 1.

The examples 1 to 3 and the comparative examples 1 to 5 were subjected to irradiation molding using ultraviolet light of 405nm, and the exposure time was set to 3.5s and the underlayer exposure time was set to 40 s. Model design was performed using solidworks, shrinkage size measurement model was 5mm cube (shrinkage rate 1-actual molded size/theoretical molded size); the tensile experiment model is designed for a reference national standard GB1040_ 92; the ultraviolet light transmittance experimental model is a cube of 20 mm; and measuring by adopting a transmission spectrocolorimeter, wherein the angle of an observer is selected to be 2 degrees, and the light source mode is selected to be C.

Through analysis of examples 1-3, the shrinkage reducing effect is most obvious by adopting the AKCONOBEL 920DU40 expanded microspheres, the ultraviolet transmittance is highest, and the tensile property is best; comparative example 1 shows that when the urethane acrylate containing no acrylic resin is used, the shrinkage rate is obviously increased and the tensile property is obviously reduced compared with the urethane acrylate containing acrylic resin; comparative example 2 shows that without adding carbon fiber powder, the shrinkage is improved by about one time and the tensile property is obviously reduced; comparative example 3 shows that when an inorganic intumescent material, SiO in the gas phase, is used₂When the test is carried out, the shrinkage rate is obviously improved, the ultraviolet light transmittance is obviously reduced, and the tensile property is also obviously reduced; in the comparative example 4, the common foaming microspheres are adopted for the experiment, and the 3D printer cannot form any model; comparative example 5 shows that when the test is carried out without the expanded microspheres, the ultraviolet transmittance and tensile strength are not changed greatly, but the shrinkage rate is obviously improved, and the comparison shows that the shrinkage rate can be obviously reduced and the molding precision can be improved by adding the high-temperature expandable microspheres. Through analysis and comparison of the experiments, the expandable carbon fiber reinforced LED photocuring 3D printing material has the characteristics of small shrinkage, high dimensional accuracy, high ultraviolet light transmittance, excellent tensile property and the like.

The above-described embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any way, and other variations and modifications may be made without departing from the spirit of the invention as set forth in the claims.

Claims

1. The LED photocuring 3D printing material reinforced by expandable carbon fibers is characterized by being prepared by mixing the following raw materials: 25-45 wt% of polyurethane acrylate resin, 50-70 wt% of diluent, 1-7 wt% of photoinitiator, 0.03-0.05 wt% of polymerization inhibitor, 0.01-0.04 wt% of expanding agent, 0.01-0.05 wt% of carbon fiber powder and 0.01-0.05 wt% of defoaming agent.

2. The expandable carbon fiber reinforced LED photocuring 3D printing material as claimed in claim 1, wherein the urethane acrylate resin is aliphatic urethane acrylate or aromatic urethane acrylate.

3. The expandable carbon fiber reinforced LED photocuring 3D printing material as recited in claim 1, wherein the polyurethane acrylate resin contains a modifier, and the modifier is an acrylic resin with a relative molecular mass of 20000-35000, and the polyurethane acrylate resin content is 75-82% and the acrylic resin content is 18-25% by weight percentage.

4. The expandable carbon fiber reinforced LED photocuring 3D printing material as claimed in claim 1, wherein the diluent is one or more selected from monofunctional reactive diluents and difunctional reactive diluents.

5. An expandable carbon fiber reinforced LED photocured 3D printing material according to claim 4, characterized in that the diluent is a compounded combination of two or more selected from hydroxyl methacrylate, alkyl acrylate, trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate.

6. An expandable carbon fiber reinforced LED photocuring 3D printing material as claimed in claim 1, wherein the photoinitiator is selected from one or two of a photoinitiator TPO and a photoinitiator 819; the polymerization inhibitor is selected from one or two of hydroquinone and p-methoxyphenol.

7. An expandable carbon fiber reinforced LED photocuring 3D printing material as claimed in claim 1, wherein the expanding agent is selected from one or more of high temperature expandable microspheres 920DU40, high temperature expandable microspheres 909DU80 and high temperature expandable microspheres 093DU 120.

8. The expandable carbon fiber reinforced LED photocuring 3D printing material as recited in claim 7, wherein the expansion agent expands at 180 ℃ at 120 ℃ and has an initial particle size of 6-38 microns and a post-expansion particle size of 30-130 microns.

9. The expandable carbon fiber reinforced LED photocuring 3D printing material as claimed in claim 1, wherein the defoaming agent is one or more of silicone defoaming agent LJ-618, KR-XP96 and mineral oil B-302 defoaming agent.

10. An expandable carbon fiber reinforced LED photocuring 3D printing material as claimed in claim 1, characterized in that the preparation method comprises the following steps:

(1) preparing all raw materials according to the proportion;