CN105524240A - Method for preparing urea-formaldehyde resin - Google Patents

Abstract

The invention discloses a method for preparing urea-formaldehyde resin. The method belongs to the field of chemical engineering. 60-65% of novel eco-friendly formaldehyde with content of 40%, 20-25% of urea with content of 46%, 4% of liquid formic acid with content of 85%, 7% of liquid caustic soda with a concentration of 35% and 4% of ammonium chloride undergo a condensation reaction to produce the urea-formaldehyde resin finished product. The method has simple processes and utilizes raw materials with abundant sources. The product has the characteristics of oil resistance, weak acid resistance, weak base resistance and mildew resistance, has good insulating properties and temperature resistance and can be used for adhesive preparation.

Description

A kind of method preparing urea-formaldehyde resin

Technical field:

Product of the present invention belongs to chemical field, particularly relates to a kind of method preparing urea-formaldehyde resin.

Background technology:

Urea-formaldehyde resin is the polymkeric substance that urea and formaldehyde reaction obtain, it is one of thermosetting resin developing comparatively morning, urea and formalin polycondensation can obtain linear urea aldehyde oligopolymer under the catalysis of acid or alkali, industrial with alkali as a catalyst, the reaction the first step generates one and dimethylolurea, then methylol and the further condensation of amino, obtain soluble resin.Urea-formaldehyde resin more easily solidifies, and the color of resin after solidification is translucent, and shape, hardness are high, oil resistant, weak acid resistant, weak base, anti-mildew, have good insulativity and temperature tolerance, but weathering resistance and water tolerance poor, life-time service nondiscoloration, also nondiscoloration during thermoforming.Urea-formaldehyde resin is mainly used in water tolerance and the less demanding goods of dielectric properties, as wiring board, switch, machine handle, meter case, knob, daily necessities, ornament, mah-jong pieces, chamber pot lid; Because its look shallow and be easy to painted, goods often rich color are magnificent.Urea-formaldehyde resin is also the main binder of domestic and international timber industry. the bonding of the slurry of sheet material, paper and fabric, thick china, decorative panel for building can be made, be used widely due to series of advantages such as its bonding strength are high, quick solidifying, good operability, abundant raw material are easy to get.But the free formaldehyde contained by urea-formaldehyde resin has toxicity, therefore the content reducing free formaldehyde in urea-formaldehyde resin is needed, the method reduced adjusts charging times, feed molar ratio, feed time exactly, and determine optimum pH value, temperature of reaction and reaction times in resin synthesis process, thus prepare the urea-formaldehyde resin of low aldehyde contenting amount, good stability.

Summary of the invention:

The problem that the present invention mainly solves just is to provide a kind of method preparing urea-formaldehyde resin, and producing the raw material that this resin uses has: content be 40% novel environment friendly formaldehyde 60-65%, content be 46% urea 20-25%, content is 85% liquid formic 4%, concentration 35% liquid caustic soda 7%, ammonium chloride 4%.

The technical solution used in the present invention is:

(1) sent in chemical reaction kettle by the novel environment friendly formaldehyde of formula ratio, start agitator, the rotating speed of agitator is 25-30 rev/min, adds the liquid formic stirring reaction 0.4-0.5 hour of formula ratio;

(2) add the urea of formula ratio to chemical reaction kettle, temperature is progressively risen to 93-95 DEG C, stirring reaction 1-1.1 hour;

(3) add the liquid caustic soda of formula ratio, stop after stirring stirring, insulation reaction 0.5-0.6 hour, after insulation reaction terminates, the ammonium chloride adding formula ratio stirs, and stops stirring to obtain finished product by blowing after being cooled to normal temperature.

Further technical scheme of the present invention is:

Temperature of reaction described in step (2) is 94 DEG C, and the reaction times is 1.05 hours.

The invention has the beneficial effects as follows: provide a kind of method preparing urea-formaldehyde resin, the method production technique is simple, abundant raw material source, and product has the feature of oil resistant, weak acid resistant, weak base, anti-mildew, also have good insulativity and temperature tolerance, product is mainly used in making tackiness agent.

Embodiment:

Embodiment:

By account for total amount be 60% novel environment friendly formaldehyde send in chemical reaction kettle, start agitator, the rotating speed of agitator is 25 revs/min, adds and accounts for the liquid formic stirring reaction 0.5 hour that total amount is 4%; To chemical reaction kettle add account for total amount be 25% urea, temperature is progressively risen to 93 DEG C, stirring reaction 1.1 hours; Add and account for the liquid caustic soda that total amount is 7%, after stirring stop stir, insulation reaction 0.5 hour, after insulation reaction terminates, add account for total amount be 4% ammonium chloride stir, after being cooled to normal temperature stop stir can blowing obtain finished product.

Embodiment 2:

By account for total amount be 62.5% novel environment friendly formaldehyde send in chemical reaction kettle, start agitator, the rotating speed of agitator is 27.5 revs/min, adds and accounts for the liquid formic stirring reaction 0.45 hour that total amount is 4%; To chemical reaction kettle add account for total amount be 22.5% urea, temperature is progressively risen to 94 DEG C, stirring reaction 1.05 hours; Add and account for the liquid caustic soda that total amount is 7%, after stirring stop stir, insulation reaction 0.55 hour, after insulation reaction terminates, add account for total amount be 4% ammonium chloride stir, after being cooled to normal temperature stop stir can blowing obtain finished product.

Embodiment 3:

By account for total amount be 65% novel environment friendly formaldehyde send in chemical reaction kettle, start agitator, the rotating speed of agitator is 30 revs/min, adds and accounts for the liquid formic stirring reaction 0.4 hour that total amount is 4%; To chemical reaction kettle add account for total amount be 20% urea, temperature is progressively risen to 95 DEG C, stirring reaction 1 hour; Add and account for the liquid caustic soda that total amount is 7%, after stirring stop stir, insulation reaction 0.6 hour, after insulation reaction terminates, add account for total amount be 4% ammonium chloride stir, after being cooled to normal temperature stop stir can blowing obtain finished product.

Claims (2)

1. prepare a method for urea-formaldehyde resin, the raw materials by weight of use calculates and comprises: content be 40% novel environment friendly formaldehyde 60-65%, content be 46% urea 20-25%, content is 85% liquid formic 4%, concentration 35% liquid caustic soda 7%, ammonium chloride 4%; It is characterized in that:

(1) sent in chemical reaction kettle by the novel environment friendly formaldehyde of formula ratio, start agitator, the rotating speed of agitator is 25-30 rev/min, adds the liquid formic stirring reaction 0.4-0.5 hour of formula ratio;

(2) add the urea of formula ratio to chemical reaction kettle, temperature is progressively risen to 93-95 DEG C, stirring reaction 1-1.1 hour;

(3) add the liquid caustic soda of formula ratio, stop after stirring stirring, insulation reaction 0.5-0.6 hour, after insulation reaction terminates, the ammonium chloride adding formula ratio stirs, and stops stirring to obtain finished product by blowing after being cooled to normal temperature.

2. a kind of method preparing urea-formaldehyde resin according to claim 1, it is characterized in that: the temperature of reaction described in step (2) is 94 DEG C, the reaction times is 1.05 hours.