A (r-nh 3 ) n n+ x n- Method for preparing monodisperse mf microspheres by catalysis

A catalytic preparation, monodisperse technology, applied in the preparation of microspheres, microcapsule preparations, etc., can solve the problems of non-recyclable, rough surface of microspheres, non-uniform particle size, etc., to achieve industrialization of products, uniform and controllable particle size , good monodispersity effect

Active Publication Date: 2021-11-30
NANJING INST OF TECH
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Problems solved by technology

Taken together, in the existing literature on the preparation of monodisperse MF microspheres, protonic acid H + Catalyzed, this type uses H + The catalytic method has defects such as uncontrollable particle size of microspheres, low conversion rate (30%-60%), rough surface of microspheres, etc.
The reason for the low pelleting rate of the above method is that due to the high activity of the catalyst, the catalytic reaction rate cannot match the pelleting rate, resulting in the deactivation of the unballed material, which cannot be recycled, resulting in the preparation process having no industrial value, and causing MF microspheres Problems such as rough surface, holes, and uneven particle size greatly limit the practical application and development of MF microspheres. For example, in the field of LCD display, MF microspheres with rough surface and many holes cannot be used as spacers to accurately control the thickness of liquid crystal films. Microsphere material use

Method used

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  • A (r-nh <sub>3</sub> ) <sub>n</sub> <sup>n+</sup> x <sup>n-</sup> Method for preparing monodisperse mf microspheres by catalysis
  • A (r-nh <sub>3</sub> ) <sub>n</sub> <sup>n+</sup> x <sup>n-</sup> Method for preparing monodisperse mf microspheres by catalysis
  • A (r-nh <sub>3</sub> ) <sub>n</sub> <sup>n+</sup> x <sup>n-</sup> Method for preparing monodisperse mf microspheres by catalysis

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] Step 1: Preparation of prepolymer

[0047] Get 5.6 g of melamine, get 10.8 g of 37% formaldehyde solution, get 18 g of deionized water, adjust the pH value of the whole system to 10 with anhydrous sodium carbonate, stir and disperse under an environment of 50°C until The solution was clear and a prepolymer solution was obtained.

[0048] Step two: Catalytic polymerization-balling;

[0049] Get above-mentioned prepolymer liquid, add the hydroxyethyl cellulose (HEC) of 0.6g as dispersant, add the ammonium chloride of 1.22g as catalyst, add the deionized water of 263.7g, place mechanical stirring under 60 ℃ of water baths ( 340r / min) and ultrasonically dispersed, settled after 3 hours of reaction, separated the supernatant and the lower solid, and dried the lower solid to obtain monodisperse MF microspheres.

[0050] Step 3: the seed polymerization cycle of the un-balled material;

[0051] 150g of the supernatant was mixed with the prepolymer liquid prepared in step 1...

Embodiment 2

[0053] Step 1: Preparation of prepolymer

[0054] Take 5.6g of melamine, take 10.8g of 37% formaldehyde solution, take 18g of deionized water, adjust the pH value of the whole system to 10 with anhydrous sodium carbonate, stir and disperse under the environment of 50°C until The solution was clear and a prepolymer solution was obtained.

[0055] Step two: Catalytic polymerization-balling;

[0056] Take the above-mentioned prepolymer solution, add 0.9g of hydroxyethyl cellulose (HEC) as a dispersant, add 1.75g ​​of ammonium acetate as a catalyst, add 262.9g of deionized water, and place it under a water bath of 65°C with mechanical stirring (200r / min) and ultrasonically disperse, settle after 3 hours of reaction, separate the supernatant liquid and the lower solid, and dry the lower solid to obtain monodisperse MF microspheres.

[0057] Step 3: the seed polymerization cycle of the un-balled material;

[0058] 150g supernatant was mixed with the prepolymer solution prepare...

Embodiment 3

[0060] Step 1: Preparation of prepolymer

[0061] Get 5.6 g of melamine, get 10.8 g of 37% formaldehyde solution, get 18 g of deionized water, adjust the pH value of the whole system to 10 with anhydrous sodium carbonate, stir and disperse under an environment of 50°C until The solution was clear and a prepolymer solution was obtained.

[0062] Step two: Catalytic polymerization-balling;

[0063] Take the above prepolymer solution, add 0.6g of polyethylene glycol 10,000 (PEG-10,000) as a dispersant, add 0.3g of ammonium sulfate as a catalyst, add 264.6g of deionized water, and place it in a water bath at 60°C Mechanical stirring (300r / min) and ultrasonic dispersion, after 3 hours of reaction, settling, separation of supernatant and lower solid, the lower solid was washed and dried to obtain monodisperse MF microspheres.

[0064] Step 3: the seed polymerization cycle of the un-balled material;

[0065] 150g of the supernatant was mixed with the prepolymer solution prepared...

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Abstract

The invention discloses a method for catalyzing the preparation of monodisperse MF microspheres. The microspheres are obtained by catalyzing a special catalyst for raw materials through the steps of prepolymerization, dispersion polymerization, and seed polymerization cycles. Compared with traditional catalysts, the polymerization rate and ball formation can be matched. The rate can significantly increase the conversion rate of prepolymer, improve the monodispersity of microspheres, and reduce or avoid holes on the surface of microspheres. This technology has the following effects: the one-way ball forming rate of the prepolymer is ≥92%, and the ball forming rate after circulation can reach 99%; the particle size of the microspheres is controllable within 0.1-10 μm, and the particle size monodispersity coefficient ε<0.060, There is basically no agglomeration phenomenon; the thermal decomposition temperature is above 300°C. The above characteristics enable the microspheres prepared by the present invention to be industrialized and have good application prospects in the fields of paint industry, cosmetics, polymer film materials, LCD spacer materials, light diffusion materials and the like.

Description

technical field [0001] The invention relates to the technical field of polymer materials, in particular to a A method for the catalytic preparation of monodisperse MF microspheres. Background technique [0002] Melamine-formaldehyde (also known as melamine, abbreviated as MF) resin microspheres are thermosetting polymer microspheres that are catalyzed by melamine and formaldehyde prepolymers through acid-catalyzed polycondensation and aggregated into balls. The particle size is about 100nm-10μm, with high Sphericity, monodispersity, heat resistance (250°C), insulation and flame retardancy, excellent mechanical properties, etc., are widely used in coatings and adhesives, cosmetics, spacer materials, polymer film materials, light diffusion materials and other fields. [0003] The preparation of MF microspheres mainly adopts a dispersion polymerization process, usually by methylolating melamine (M) and formaldehyde (F) solutions under alkaline conditions to form a prepolymer ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J13/14C08G12/32
CPCB01J13/14C08G12/32
Inventor 黄玉安曹沈炀杨振誉杨凯娜柏思天侯欣培韩冰杭祖圣吴凡
Owner NANJING INST OF TECH
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