1. A preparation method of a high-strength silicon nitride artificial eye holder is characterized by comprising the following steps:

(1) mixing silicon nitride powder, water, a sintering aid and a binder to obtain ceramic slurry;

(2) dipping a porous organic spherical matrix consisting of holes and hole ribs into the ceramic slurry and taking out to obtain a biscuit in which the porous organic spherical matrix hole ribs are wrapped by the ceramic slurry;

(3) drying the dipped biscuit in air atmosphere to obtain a ceramic body;

(4) and sintering the dried ceramic blank in nitrogen to obtain the high-strength silicon nitride ceramic artificial eye seat with the three-dimensional interconnected pore structure.

2. The preparation method according to claim 1, wherein the porous organic spherical matrix is made of one of polyurethane, polyether and epoxy resin; preferably, the porous organic spherical matrix has a pore density of 50-25 ppi and an aperture ratio of more than or equal to 85%; more preferably, the porous organic spherical matrix has a pore density of 35-30 ppi and an aperture ratio of 95% or more.

3. The production method according to claim 1 or 2, wherein the sintering aid is selected from at least one of magnesium oxide, yttrium oxide, and europium oxide; the binder is selected from at least one of polyvinyl alcohol, gelatin and hydroxypropylmethylcellulose.

4. The method according to any one of claims 1 to 3, wherein the solid content of the ceramic slurry is 20 to 60wt%, preferably 30 to 50 wt%.

5. The method according to any one of claims 1 to 4, wherein the sintering aid is 1 to 8wt%, preferably 3 to 5wt% of the silicon nitride powder.

6. The method according to any one of claims 1 to 5, wherein the binder is present in an amount of 1 to 10wt%, preferably 3 to 8wt%, based on the weight of the silicon nitride powder.

7. The method according to any one of claims 1 to 6, wherein the porous organic spherical substrate is impregnated into the ceramic slurry for 1 to 5 times, preferably 1 to 3 times, more preferably 2 to 3 times; and each immersion in the slurry is carried out for 5s to 10s, preferably 3s to 8 s.

8. The method of claims 1-7, wherein after each impregnation, drying is carried out in an air atmosphere at 15 ℃ to 45 ℃ for 3 hours to 6 hours.

9. The method as claimed in claims 1 to 8, wherein the ceramic prosthetic eye holder with high strength and low density having three-dimensional interconnected pore structure is obtained by drying and sintering at 1800 ℃ for 1-2 hours in a nitrogen atmosphere.

10. The high-strength silicon nitride artificial eye holder prepared according to the preparation method of any one of claims 1 to 9, wherein the high-strength silicon nitride artificial eye holder has a compressive strength of 6 to 50MPa, a porosity of 55 to 90%, and a pore diameter of 200 to 800 μm.

Background

Currently, the ocular prosthesis bases used clinically are mainly solid spheres represented by silica gel and porous bioceramic ocular prosthesis bases represented by Hydroxyapatite (HA). China also prepares the porous HA artificial eye seat by taking coral, animal bones or chemically synthesized HA and the like as raw materials. The ceramic prosthetic eye holder generally requires a porosity (60-80%), a large pore size (200-500 μm), and a low density (not more than 2 g/cm)³) And has certain strength (the compression strength is more than or equal to 2 MPa).

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide a porous ceramic prosthetic socket material having high strength and a molding method.

In one aspect, the invention provides a preparation method of a high-strength silicon nitride artificial eye holder, which comprises the following steps:

(1) mixing silicon nitride powder, water, a sintering aid and a binder to obtain ceramic slurry;

(2) dipping a porous organic spherical matrix consisting of holes and hole ribs into the ceramic slurry and taking out to obtain a biscuit in which the porous organic spherical matrix hole ribs are wrapped by the ceramic slurry;

(3) drying the dipped biscuit in air atmosphere to obtain a ceramic body;

(4) and sintering the dried ceramic blank in nitrogen to obtain the high-strength silicon nitride ceramic artificial eye seat with the three-dimensional interconnected pore structure. In the sintering process, the porous organic spherical matrix is gasified and discharged after being decomposed at high temperature, and the silicon nitride powder attached to the organic pore ribs is sintered.

Preferably, the material of the porous organic spherical matrix is one of polyurethane, polyether and epoxy resin.

Preferably, the porous organic spherical matrix has a pore density of 50-25 ppi and a porosity of more than or equal to 85%; preferably, the porous organic spherical matrix has a pore density of 35-30 ppi and an aperture ratio of 95% or more.

Preferably, the sintering aid is selected from at least one of magnesium oxide, yttrium oxide and europium oxide; the binder is selected from at least one of polyvinyl alcohol, gelatin and hydroxypropylmethylcellulose.

Preferably, the solid content of the ceramic slurry (the ratio of the total mass of the silicon nitride powder, the sintering aid and the binder to the total mass of the ceramic slurry) is 20wt% to 60wt%, and preferably 30wt% to 50 wt%. The solid content is low, the viscosity of the ceramic slurry is low, the ceramic slurry is not easy to adhere to the organic matrix hole ribs, and the strength is low after sintering; high solid content and high viscosity, is easy to cause the surface of the porous organic spherical matrix to block pores, and has low porosity after sintering.

Preferably, the mass of the sintering aid is 1-8 wt% of the mass of the silicon nitride powder, and preferably 3-5 wt%.

Preferably, the mass of the binder is 1 to 10wt% of the mass of the silicon nitride powder, and preferably 3 to 8 wt%. The ceramic slurry can not be attached or a small amount of the ceramic slurry can not be attached to the hole ribs of the organic matrix, and the ceramic slurry can not be sintered and molded. The content of the binder is too high, the viscosity of the ceramic slurry is too high, the surface of the porous organic spherical matrix is easy to block holes, and the porosity after sintering is low.

Preferably, the porous organic spherical matrix is dipped into the ceramic slurry for 1 to 5 times, preferably 1 to 3 times, and more preferably 2 to 3 times; and each immersion in the slurry is carried out for 5s to 10s, preferably 3s to 8 s. The dipping times are less, the ceramic slurry attached to the porous organic spherical matrix pore ribs is less, and the strength after sintering is low. The impregnation times are large, the ceramic attached to the porous organic spherical matrix is large, the surface pore blocking phenomenon can be caused, and the porosity after sintering is low.

Preferably, after each impregnation, the mixture is dried in an air atmosphere at 15 to 45 ℃ for 3 to 6 hours.

Preferably, after drying, sintering the ceramic prosthetic eye seat for 1 to 2 hours at 1750-1800 ℃ in a nitrogen atmosphere to obtain the high-strength low-density ceramic prosthetic eye seat with the three-dimensional interconnected pore structure.

On the other hand, the invention also provides the high-strength silicon nitride artificial eye holder prepared by the preparation method, wherein the compressive strength of the high-strength silicon nitride artificial eye holder is 6-50 MPa, the porosity is 55-90%, and the pore size is 200-800 μm.

Has the advantages that:

in the invention, silicon nitride is a high-strength biological inert material, and compared with hydroxyapatite, the artificial eye holder with high porosity and high strength is easy to prepare.

According to the preparation method provided by the invention, the ceramic artificial eye seat with a complex structure, high porosity, controllable pore size and high mechanical property can be prepared. And the method has low cost, simple process and low subsequent processing amount, and is suitable for industrial scale production, thereby having good development prospect.

Drawings

FIG. 1 is a photograph showing the appearance of the silicon nitride artificial eye socket prepared in example 3;

FIG. 2 is a photograph showing the appearance of the silicon nitride artificial eye socket prepared in comparative example 4;

FIG. 3 is a microscopic topography of the 2-time silicon nitride prosthetic eye socket dipped in example 2;

FIG. 4 is a microscopic topography of the silicon nitride prosthetic eye socket dipped 3 times in example 3;

FIG. 5 is a microscopic topography of the 3-time silicon nitride eyebox of example 3, which has a columnar grain topography;

FIG. 6 is a graph showing the compressive strength of the silicon nitride artificial eye socket in examples 1-3 at different numbers of impregnations.

Detailed Description

The present invention is further illustrated by the following examples, which are to be understood as merely illustrative and not restrictive.

In the disclosure, the porous ceramic prosthetic eye holder is made of silicon nitride ceramic, the compressive strength can be 15-50MPa, the porosity can be 60-90%, and the pore density can be 200-800 μm.

In one embodiment of the invention, the porous silicon nitride artificial eye seat is prepared by taking silicon nitride ceramic powder, water, a sintering aid, a binder and the like as raw materials and controlling the solid content of the raw material powder in the water, the content of the binder, the pore density of the porous organic spherical matrix and other influencing factors. The preparation method of the high-strength silicon nitride artificial eye seat provided by the invention is exemplarily described as follows.

The porous organic spherical matrix consists of pores and pore ribs. Wherein the porous organic spherical matrix is one of polyurethane, polyether or epoxy resin organic matter, the pore density of the porous organic spherical matrix can be 50-25 ppi (preferably 35-30 ppi), and the aperture ratio is more than or equal to 95%. The porous organic spherical matrix used in the present invention is generally commercially available.

The raw materials of silicon nitride ceramic powder, water, sintering aid, binder and the like are stirred and mixed to form ceramic slurry. The sintering aid is one or more of magnesium oxide, yttrium oxide, europium oxide and the like. Preferably, the binder is one or more of polyvinyl alcohol, gelatin and hydroxypropyl methyl cellulose. The solid content of the ceramic slurry is 20 to 60wt%, preferably 30 to 50 wt%. The content of the sintering aid is 1-8 wt%, preferably 3-5 wt% of the silicon nitride powder, and if the sintering aid is not added, the silicon nitride cannot be sintered. The content of the binder is 1 to 10wt%, preferably 3 to 8wt% of the silicon nitride powder.

And (3) soaking the porous organic ball into the ceramic slurry for multiple times, taking out, drying and molding to obtain a ceramic blank. The porous organic spherical matrix is impregnated into the ceramic slurry for 1 to 5 times, preferably 2 to 3 times. Each immersion is carried out in the slurry for a period of time of 5 to 10 seconds, preferably 3 to 8 seconds. After impregnation, drying for 3-6h at 15-45 ℃ in air atmosphere, and then carrying out subsequent impregnation.

And sintering the dried ceramic blank in nitrogen to obtain the high-strength/low-density silicon nitride artificial eye seat with the three-dimensional interconnected pore structure.

The present invention will be described in detail by way of examples. It is also to be understood that the following examples are illustrative of the present invention and are not to be construed as limiting the scope of the invention, and that certain insubstantial modifications and adaptations of the invention by those skilled in the art may be made in light of the above teachings. The specific process parameters and the like of the following examples are also only one example of suitable ranges, i.e., those skilled in the art can select the appropriate ranges through the description herein, and are not limited to the specific values exemplified below.

Example 1:

10g of silicon nitride ceramic powder, 0.5g of magnesium oxide, and 0.5g of polyvinyl alcohol and 22.3g of water were stirred to form a ceramic slurry. And (3) soaking the polyurethane porous spherical organic matter with the pore density of 30ppi into the ceramic slurry for 5s, and taking out air and drying for 6 h. And finally sintering the porous silicon nitride artificial eye seat for 2 hours at 1750 ℃ in nitrogen to obtain the porous silicon nitride artificial eye seat.

Example 2:

10g of silicon nitride ceramic powder, 0.5g of magnesium oxide, and 0.5g of polyvinyl alcohol and 22.3g of water were stirred to form a ceramic slurry. And (3) soaking the porous spherical polyurethane organic matter with the pore density of 30ppi into the ceramic slurry for 5s, taking out the ceramic slurry, drying the ceramic slurry for 6h, soaking the ceramic slurry into the ceramic slurry for 5s again, and drying the ceramic slurry for 6h again in the air. And finally sintering the porous silicon nitride artificial eye seat for 2 hours at 1750 ℃ in nitrogen to obtain the porous silicon nitride artificial eye seat.

Example 3:

10g of silicon nitride ceramic powder, 0.5g of magnesium oxide, and 0.5g of polyvinyl alcohol and 22.3g of water were stirred to form a ceramic slurry. And (3) soaking the porous spherical polyurethane organic matter with the pore density of 30ppi into the ceramic slurry for 5s, taking out the ceramic slurry, drying the ceramic slurry for 6h by air, soaking the ceramic slurry into the ceramic slurry for 5s again, drying the ceramic slurry in the air for 6h again, soaking the ceramic slurry into the ceramic slurry for 5s for the third time, and drying the ceramic slurry in the air for 6h again. And finally sintering the porous silicon nitride artificial eye seat for 2 hours at 1750 ℃ in nitrogen to obtain the porous silicon nitride artificial eye seat.

Example 4:

10g of silicon nitride ceramic powder, 0.5g of magnesium oxide, and 0.5g of polyvinyl alcohol and 22.3g of water were stirred to form ceramic slurry 1. And (3) soaking the polyurethane porous spherical organic matter with the pore density of 35ppi into the ceramic slurry 1 for 5s, and taking out air and drying for 6 h. 10g of silicon nitride ceramic powder, 0.5g of yttrium oxide, 0.5g of gelatin and 14g of water are stirred to form ceramic slurry 2, and the dried organic balls are immersed in the ceramic slurry 2 again for 10 seconds and then dried in the air for 6 hours. 10g of silicon nitride ceramic powder, 0.8g of europium, 0.8g of gelatin and 9g of water were stirred to form ceramic slurry 3. The dried organic spheres were immersed in the slurry 3 again for 10 seconds and then dried in air for 6 hours. And finally sintering the porous silicon nitride artificial eye seat for 2 hours at 1800 ℃ in nitrogen to obtain the porous silicon nitride artificial eye seat.

Comparative example 1:

the procedure for preparing the porous silicon nitride artificial eye seat in comparative example 1 is as follows, with reference to example 1: 10g of silicon nitride ceramic powder, 0.5g of magnesium oxide, and 0g of polyvinyl alcohol and 22.8g of water were stirred to form a ceramic slurry. And (3) soaking the polyurethane porous spherical organic matter with the pore density of 30ppi into the ceramic slurry for 5s, and taking out air and drying for 6 h. Finally sintering the mixture for 2 hours at 1750 ℃ in nitrogen. Because of no adhesive, the slurry is only attached to the hole ribs of the organic matrix in a small amount and cannot be sintered and molded.

Comparative example 2:

the procedure for preparing the porous silicon nitride artificial eye seat in comparative example 2 was as described in example 1, except that: 10g of silicon nitride ceramic powder, 0.5g of magnesium oxide, and 1.5g of polyvinyl alcohol and 21.3g of water were stirred to form a ceramic slurry. And (3) soaking the porous spherical polyurethane organic matter with the pore density of 30ppi into the ceramic slurry for 5s, taking out air, drying for 6h, and sintering for 2h at 1750 ℃ in nitrogen to obtain the porous silicon nitride artificial eye seat. Due to the large viscosity of the slurry, the surface of the sintered slurry is seriously blocked.

Comparative example 3:

the procedure for preparing the porous silicon nitride artificial eye seat in this comparative example 3 was as described in example 3, except that: 10g of silicon nitride ceramic powder, 0.5g of magnesium oxide, and 0.5g of polyvinyl alcohol and 89g of water were stirred to form ceramic slurry. And (3) soaking the porous spherical polyurethane organic matter with the pore density of 30ppi into the ceramic slurry for 5s, taking out the ceramic slurry, drying the ceramic slurry for 6h by air, soaking the ceramic slurry into the ceramic slurry for 5s again, drying the ceramic slurry in the air for 6h again, soaking the ceramic slurry into the ceramic slurry for 5s for the third time, and drying the ceramic slurry in the air for 6h again. And finally sintering the porous silicon nitride artificial eye seat for 2 hours at 1750 ℃ in nitrogen to obtain the porous silicon nitride artificial eye seat. Because the solid content of the slurry is extremely low, only a small amount of the slurry is attached to the hole ribs of the organic matrix, and the strength of the sintered and molded slurry is low.

Comparative example 4:

the procedure for preparing the porous silicon nitride artificial eye seat in this comparative example 4 was as described in example 3, except that: 10g of silicon nitride ceramic powder, 0.5g of magnesium oxide, and 0.5g of polyvinyl alcohol and 7.18g of water were stirred to form a ceramic slurry. And (3) soaking the porous spherical polyurethane organic matter with the pore density of 30ppi into the ceramic slurry for 5s, taking out the ceramic slurry, drying the ceramic slurry for 6h by air, soaking the ceramic slurry into the ceramic slurry for 5s again, drying the ceramic slurry in the air for 6h again, soaking the ceramic slurry into the ceramic slurry for 5s for the third time, and drying the ceramic slurry in the air for 6h again. And finally sintering the porous silicon nitride artificial eye seat for 2 hours at 1750 ℃ in nitrogen to obtain the porous silicon nitride artificial eye seat. Because the solid content of the slurry is high, the surface of the sintered and molded product is more blocked.

Comparative example 5:

the procedure for preparing the porous silicon nitride artificial eye seat in this comparative example 5 was as described in example 3, except that: 10g of silicon nitride ceramic powder, 0.5g of polyvinyl alcohol and 22.8g of water were stirred to form a ceramic slurry. And (3) soaking the porous spherical polyurethane organic matter with the pore density of 30ppi into the ceramic slurry for 5s, taking out the ceramic slurry, drying the ceramic slurry for 6h by air, soaking the ceramic slurry into the ceramic slurry for 5s again, drying the ceramic slurry in the air for 6h again, soaking the ceramic slurry into the ceramic slurry for 5s for the third time, and drying the ceramic slurry in the air for 6h again. Finally sintering the mixture for 2 hours at 1750 ℃ in nitrogen. Because no sintering aid is contained, the molding cannot be realized by sintering.

Table 1 shows the preparation raw materials and performance parameters of the porous silicon nitride ceramic artificial eye seat prepared by the present invention:

the appearance of the high-strength silicon nitride porous ceramic artificial eye holder prepared in the embodiment 3 of the invention is shown in fig. 1. FIG. 2 is an appearance picture of the silicon nitride artificial eye socket prepared in comparative example 4, which shows a serious surface plugging phenomenon after sintering due to the high solid content and high viscosity of the ceramic slurry; fig. 3-5 are micrographs of silicon nitride prosthetic eye sockets taken at different immersion times. As can be seen from fig. 3-5, the number of impregnations increases and the pore density thickness increases. The generation of silicon nitride rod-like crystals during sintering is a main cause of high strength of the silicon nitride artificial eye holder. FIG. 6 shows compressive strengths of silicon nitride prosthetic eye sockets with different dipping times, and the strengths increased with increasing dipping times.