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A kind of transparent ceramic orthodontic bracket and preparation method thereof

A technology of orthodontic brackets and transparent ceramics, which is applied in the field of ceramics, can solve the problems of long deglue time, low light transmittance of transparent ceramics, and low green strength, so as to avoid rearrangement and agglomeration, facilitate automatic production, and feed smooth surface effect

Active Publication Date: 2022-07-01
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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  • A kind of 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 , with a particle size of 1 μm, 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. On the internal mixer, the injection molding feedstock was first banburyed at a temperature of 190 degrees for 2 hours, then cooled to 50 degrees, and kneaded for 0.5 hours. The content of high-purity nano-alumina powder in the feed was: 80.5 parts, the binder The content of 19.5 parts.

[0067] 2. Add the mixture in step 1 into a screw extruder granulator, the temperature is 180 degrees, the screw speed is 400 rpm, and the transparent alumina feed particles are prepared after dicing.

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

[0069] 4...

Embodiment 2

[0074] a. The specific surface area of ​​alumina powder is 10g / m 2 , the particle size is 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. On the internal mixer, the injection molding feedstock was first banburyed at a temperature of 190 degrees for 2 hours, then cooled to 50 degrees, and kneaded for 0.5 hours. The content is 18.5 parts.

[0077] 2. Add the mixture in step 1 into a screw extruder granulator, the temperature is 180 degrees, the screw speed is 400 rpm, and the transparent alumina feed particles are prepared after dicing.

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

[0079] 4. Put the ceramic bracket in step 3 in an oxalic acid catalytic degreasing furnace at a...

Embodiment 3

[0083] a. The specific surface area of ​​alumina powder is 7g / m2 , the particle size is 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, and 3 parts of dispersant-polyether modified heptamethyltrisiloxane.

[0085] 1. On the internal mixer, the injection molding feedstock is first banburyed at a temperature of 190 degrees for 2 hours, then cooled to 50 degrees, and kneaded for 0.5 hours. The content of high-purity nano-alumina powder in the feed is 83 parts, and the amount of the binder The content is 18 servings.

[0086] 2. Add the mixture in step 1 into a screw extruder granulator, the temperature is 190 degrees, the screw speed is 400 rpm, and the transparent alumina feed particles are prepared after granulation.

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

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Abstract

The invention discloses a transparent ceramic orthodontic bracket and a preparation method thereof. The raw materials for the preparation of transparent ceramic orthodontic brackets include the following components by weight: 80-90 parts of nano-alumina, and 10-20 parts of a binder; the binder includes the following five components: the first part is a low molecular weight component : contains at least one of paraffin wax, microcrystalline wax, beeswax, EBS wax and PE wax; the second part is the catalytic component: homopolyoxymethylene with high melt index; the third part is the skeleton component: containing polypropylene, At least one of polyethylene, ethylene-vinyl acetate copolymer, POE, and polystyrene; the fourth part is a plasticizer; the fifth part is a silicone dispersant. The transparent ceramic bracket of the invention has high density, few pores, high light transmittance and high 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] Transparent orthodontic ceramic brackets were introduced in 1986 and quickly became an alternative to plastic 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, and are not easy to color and release gas. In terms of light transmittance, color, wear resistance, and biocompatibility, they have the incomparable advantages of brackets made of other materials. 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 ceramic brackets are divided i...

Claims

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Application Information

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Patent Type & Authority Patents(China)
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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