Thermostable metaformaldehyde containing condensate of melamine and formaldehyde, and its preparation method

A technology of melamine formaldehyde and thermal stability, applied in the field of thermally stable polyoxymethylene and its preparation, can solve the problems of reduced production efficiency, unsatisfactory effect, easy volatilization and the like, and achieves the effect of solving the problem of clogging

Inactive Publication Date: 2006-02-08
YUNNAN YUNTIANHUA +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, there are still the following problems that need to be solved urgently in production and application: (1) Due to the low molecular weight of this type of formaldehyde absorbent, it is easy to volatilize during high-temperature processing and reduce the stabilization effect, and condense to block the vacuum exhaust port of the processing equipment, thereby reducing production. efficiency; (2) This type of formaldehyde absorbent is easy to migrate to form mold scale, which seriously affects the apparent quality and production efficiency of the product; (3) The addition of this type of formaldehyde absorbent will reduce the mechanical properties of the POM body, especially the impact toughness
Chinese patent CN1569957A discloses the thermal stabilization effect of polyamide on POM. It has the advantages of stable structure, high molecular weight and low volatility, and good compatibility with POM. However, the apparent quality of POM is affected due to the high-temperature oxidation and discoloration of the amide group.
Chinese patent ZL96196799.4 reports the use of vinyl polymers with primary amide groups and imide groups as POM formaldehyde absorbents, but its high temperature stability affects its thermal stability.
Chinese patent 94115800.4 has reported polyoxymethylene composition and application thereof, and this polyoxymethylene composition has adopted melamine formaldehyde condensate as formaldehyde absorber, and this formaldehyde absorber is general-purpose melamine formaldehyde condensate, and its effect is not ideal: consumption is relatively It is difficult to effectively play the role of formaldehyde absorbent if the amount is too small, and the mechanical properties of polyoxymethylene will be damaged if the amount is too much

Method used

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  • Thermostable metaformaldehyde containing condensate of melamine and formaldehyde, and its preparation method
  • Thermostable metaformaldehyde containing condensate of melamine and formaldehyde, and its preparation method
  • Thermostable metaformaldehyde containing condensate of melamine and formaldehyde, and its preparation method

Examples

Experimental program
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Effect test

Embodiment 1

[0054] Add 100g MA into the three-neck flask, and add formaldehyde solution according to the molar ratio of MA to FA of 1:1.2. Raise the temperature to 60°C, add 5g of gelatin / sodium carboxyformaldehyde cellulose (4:1) composite dispersant, adjust the pH value to 6.3, after the reaction system appears white turbidity, raise the temperature to 95°C, react for 1 hour, adjust the pH value to 7.0, terminate the reaction. The condensation product is washed and filtered and stored at low temperature.

[0055] Mix polyformaldehyde resin 10Kg with tetrakis [β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] pentaerythritol ester 50g, melamine-formaldehyde condensate 70g, calcium carbonate 20g, glycerol monostearate 10 g was added into a high-speed mixer for mixing, and a vented twin-screw extruder was used for melting and kneading, extrusion and granulation to obtain thermally stable polyoxymethylene. Screw speed, 50 rpm; barrel temperature, 140-190°C.

Embodiment 2

[0057] Add 100g MA into a three-necked flask, add formaldehyde solution according to the molar ratio of MA to FA of 1:1.5, heat and stir in a water bath. Heat to 75°C, add 10g of gelatin / sodium carboxyformaldehyde cellulose (4:1.5) composite dispersant, adjust the pH value to 6.5, after the reaction system appears white turbidity, raise the temperature to 90°C, react for 1.5 hours, adjust the pH value to 7.2, Stop the reaction. The condensation product is washed and filtered and stored at low temperature.

[0058] Mix polyoxymethylene resin 10Kg with bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl) triethylene glycol ester 40g, melamine-formaldehyde condensate 90g, magnesium oxide 10g, bis Add 20 g of stearamide into a high-speed mixer and mix, melt and knead with a vented twin-screw extruder, extrude and granulate to obtain heat-stable polyoxymethylene. Screw speed, 90 rpm; barrel temperature, 150-200°C.

Embodiment 3

[0060] Add 100g MA into a three-necked flask, add formaldehyde solution according to the molar ratio of MA to FA of 1:2, heat and stir in a water bath. Heat to 70°C, add 15g of gelatin / polyvinyl alcohol (4:2) composite dispersant, adjust the pH value to 6.4, after the reaction system becomes white and turbid, raise the temperature to 93°C, react for 1 hour, adjust the pH value to 6.8, Stop the reaction. The condensation product is washed and filtered and stored at low temperature.

[0061] Mix polyoxymethylene resin 10Kg with bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] 1,6-hexanediol ester 30g, melamine-formaldehyde condensate 150g, calcium silicate 7g 10 g of pentaerythritol tristearate was added into a high-speed mixer and mixed, and the vented twin-screw extruder was adopted to melt and knead, extrude and granulate to obtain heat-stable polyoxymethylene. Screw speed, 150 rpm; barrel temperature, 170-230°C.

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Abstract

The invention discloses a thermostable metaformaldehyde containing condensate of melamine and formaldehyde, and its preparation method, which consists of charging melamine and methyl aldehyde into a bottle with a stirrer, a temperature gage and a reflux condenser, charging composite disperser solution 5-15 weight parts at 60-75 deg C, adjusting pH to 6.3-6.5, elevating temperature to 80-95 deg C, reacting 0.5-1.5 hrs, adjusting pH to 6.8-7.2, stopping the reaction, washing and filtering the reactant, thus obtaining MF condensate and storing at low temperature, then charging polyoxymethylene resin 100 weight parts, melamine methylene oxide condensate 0.07-1.8 weight parts, anti-oxidizing agent 0.1-0.5 part, formic acid absorbent 0.05-0.5 weight part, lubricating agent 0.1-0.5 weight part into a high speed mixing machine, melting with exhaustion type double screw bolt extrusion machine for squeezing and granulating.

Description

1. Technical field [0001] The invention relates to a thermally stable polyoxymethylene containing melamine-formaldehyde condensate (MF) and a preparation method thereof, belonging to the field of polymer processing. 2. Background technology [0002] Formaldehyde absorbent is a very important auxiliary heat stabilizer for polyoxymethylene (POM). At present, low-molecular compounds such as melamine (MA) and dicyandiamide are generally used as formaldehyde absorbents in the industry. Formaldehyde is absorbed by the addition of formaldehyde. Since the molecules of this type of compound contain a large number of unreacted active hydrogen atoms, it shows a high thermal stability efficiency. However, there are still the following problems that need to be solved urgently in production and application: (1) Due to the low molecular weight of this type of formaldehyde absorbent, it is easy to volatilize during high-temperature processing and reduce the stabilization effect, and condens...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08L59/02C08K5/3492
Inventor 叶林胡友亮赵晓文
Owner YUNNAN YUNTIANHUA
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