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Transparent ceramic orthodontic bracket and preparation method thereof

An orthodontic bracket and transparent ceramic technology, applied in the field of ceramics, can solve the problems of difficult thermal decomposition, shrinkage, rearrangement of powder particles, etc., and achieve high three-point bending strength, improved fluidity, and good compatibility. Effect

Active Publication Date: 2020-07-28
浙江昶研新材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this type of binder is very easy to obtain low-viscosity, high-fluidity feed, there are the following problems in the production practice process: 1. There are too many low-molecular components, it is not easy to thermally decompose, the debinding time is long, and it is easy to cause injection Defects, such as shrinkage cavities, surface bubbling, weld lines and other defects; 2. The strength of the prepared green body is low, the tailings are difficult to come out, and it is difficult to realize automatic production; 3. During the solvent degreasing process, polymer swelling is easy to occur, and particles It is very easy to rearrange, causing bubbling, cracking and dimensional deformation; 4. The process of degumming requires a large amount of organic solvents, which is not environmentally friendly; Capillary pore channels, coupled with a large amount of low-melting binder components, form a liquid phase during the heating and debinding process to produce a siphon phenomenon, which will rearrange the powder particles and cause a large number of micropores due to local agglomeration
Fatal microporous defects lead to low light transmittance of alumina transparent ceramics, poor sintered strength, particle rearrangement and agglomeration will also lead to sintering deformation of the product, and poor dimensional accuracy
This is the reason why transparent alumina orthodontic brackets are not widely used in the ceramic injection molding process

Method used

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  • Transparent ceramic orthodontic bracket and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0064] a. The specific surface area of ​​alumina powder is 20g / m 2 , particle size 1μm, high-purity alumina.

[0065] b. The binder ratio is: 73 parts of polyoxymethylene, 5 parts of paraffin wax, 5 parts of EBS wax, 7 parts of EVA, 7 parts of PP, 1.5 parts of DOP, 1.5 parts of dispersant-polyether modified heptamethyltrisiloxane .

[0066] 1. Mix the injection molding feed for 2 hours at a temperature of 190 degrees on the internal mixer, then lower the temperature by 50 degrees, and knead for 0.5 hours. The content of high-purity nano-alumina powder in the feed is: 80.5 parts, binder The content is 19.5 parts.

[0067] 2. Put the mixture in step 1 into a screw extruder granulator at a temperature of 180°C and a screw speed of 400 rpm, and cut into pellets to prepare transparent alumina feed granules.

[0068] 3. The feed particles in step 2 are injection-molded on a ceramic injection molding machine to prepare a ceramic bracket.

[0069] 4. Put the ceramic bracket in ste...

Embodiment 2

[0074] a. The specific surface area of ​​alumina powder is 10g / m 2 , particle size of 0.5μm, high-purity alumina.

[0075] b. The binder ratio is: 65 parts of polyoxymethylene, 5 parts of paraffin wax, 7 parts of EBS wax, 10 parts of EVA, 10 parts of PP, 1.5 parts of DOP, 1.5 parts of dispersant-polyether modified heptamethyltrisiloxane .

[0076] 1. Mix the injection molding feed for 2 hours at a temperature of 190 degrees on the internal mixer, then lower the temperature by 50 degrees, and knead for 0.5 hours. The content of high-purity nano-alumina powder in the feed is 81.5 parts, and the content of the binder The content is 18.5 parts.

[0077] 2. Put the mixture in step 1 into a screw extruder granulator at a temperature of 180°C and a screw speed of 400 rpm, and cut into pellets to prepare transparent alumina feed granules.

[0078] 3. The feed particles in step 2 are injection-molded on a ceramic injection molding machine to prepare a ceramic bracket.

[0079] 4. P...

Embodiment 3

[0083] a. The specific surface area of ​​alumina powder is 7g / m2 , particle size of 0.5μm, high-purity alumina.

[0084] b. The binder ratio is: 60 parts of polyoxymethylene, 5 parts of paraffin wax, 10 parts of EBS wax, 10 parts of EVA, 10 parts of PS, 2 parts of DOP, 3 parts of dispersant-polyether modified heptamethyltrisiloxane.

[0085] 1. Mix the injection molding feed for 2 hours at a temperature of 190 degrees on the internal mixer, then lower the temperature by 50 degrees, and knead for 0.5 hours. The content of high-purity nano-alumina powder in the feed is 83 parts, and the amount of binder Contains 18 servings.

[0086] 2. Put the mixture in step 1 into a screw extruder granulator at a temperature of 190°C and a screw speed of 400 rpm, and cut into pellets to prepare transparent alumina feed granules.

[0087] 3. The feed particles in step 2 are injection-molded on a ceramic injection molding machine to prepare a ceramic bracket.

[0088] 4. Put the ceramic brack...

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Abstract

The invention discloses a transparent ceramic orthodontic bracket and a preparation method thereof. The transparent ceramic orthodontic bracket comprise the following components in parts by weight: 80-90 parts of nano aluminum oxide and 10-20 parts of a binder, wherein the binder comprises the following five parts: a first part is a low-molecular component containing at least one of paraffin, microcrystalline wax, bee wax, EBS wax and PE wax, a second part is a catalytic component, namely homo-polymerized polyformaldehyde with a high melt index; a third part is a skeleton component containingat least one of polypropylene, polyethylene, an ethylene-vinyl acetate copolymer, POE and polystyrene; a fourth part is a plasticizer; and a fifth part is an organic silicon dispersing agent. The transparent ceramic bracket is high in density, few in air holes, high in light transmission and high in three-point bending strength.

Description

technical field [0001] The invention belongs to the field of ceramics, and in particular relates to a transparent ceramic orthodontic bracket and a preparation method thereof. Background technique [0002] In 1986, transparent orthodontic ceramic brackets came out and quickly became an alternative to plastic brackets and metal brackets. The raw materials for making transparent ceramic brackets are mainly alumina and zirconia, of which alumina is used more. Alumina transparent ceramic brackets have high strength, high transparency, are not easy to color and release gas, and have incomparable advantages in terms of light transmittance, color, wear resistance and biocompatibility, etc., which brackets made of other materials cannot match. Therefore, as dental patients, especially women, have higher and higher requirements for aesthetics, the market application range of transparent ceramic brackets is increasing. [0003] At present, alumina transparent ceramic brackets are di...

Claims

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Application Information

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IPC IPC(8): C04B35/634C04B35/632C04B35/10C04B35/638
CPCC04B35/63496C04B35/63472C04B35/63404C04B35/63408C04B35/632C04B35/10C04B35/638C04B2235/6562C04B2235/6567C04B2235/661C04B2235/77C04B2235/9646C04B2235/6022C04B2235/96C04B2235/6582C04B2235/6581
Inventor 梁良华王雅雷刘怀菲游峰
Owner 浙江昶研新材料有限公司
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