CN101463117B - Preparation of methyl butyl mixedly etherified melamine formaldehyde resin - Google Patents

Abstract

The invention discloses a method for preparing a methyl-butyl mixed etherified melamine formaldehyde resin by taking paratoluenesulfonic acid-butanol solution as a catalyst. The method is characterized in that the melamine formaldehyde resin is prepared from the following components calculated by weight percentages: 20-30% of 37% formaldehyde solution, 10-25% of melamine, 20-50% of methanol and 20-50% of butanol. In the method, domestic 37wt/% aqueous methanol solution is taken as a raw material, and alkali and acid are employed to adjust the pH value of a reaction system, thus controlling the reaction rate.

Description

A kind of preparation method of methyl butyl complex etherified melamine formaldehyde resin

Technical field

The present invention relates to the macromolecular material specialty in the chemical industry field, specifically, relate to a kind of synthetic resins that is suitable for application of paints, i.e. the preparation method of etherified melamine amine formaldehyde.

Background technology

Terpolycyantoamino-formaldehyde resin is the polymkeric substance that is obtained by trimeric cyanamide and formolite reaction; Claim melamine formaldehyde resin or melmac again, after this resin through machine-shaping crosslinking reaction takes place, generate insoluble not melting property product; Its water white transparency; Stable in boiling water, even can be 150 ℃ of uses, and have good mechanical property.Etherify melamine formaldehyde resin with pure etherificate modification can be used as coating and thermo-setting paint.

Abroad the research of terpolycyantoamino-formaldehyde resin and be produced in the beginning last century the '30s.Late nineteen seventies American Cyanamid Company at first releases the high solid methyl-etherified terpolycyantoamino-formaldehyde resin of a kind of Cymel by name, has released tandem product of the same name again in late nineteen eighties subsequently, and methyl butyl complex etherified melamine formaldehyde resin is wherein just arranged.U.S. Meng three all chemical company also to have developed the trade mark be the methyl butyl complex etherified melamine formaldehyde resin of 757 grades.In addition, German BASF group company, Britain BIP company and big Japanese ink company etc. also have corresponding product to go on the market.

Methyl butyl complex etherified melamine formaldehyde resin belongs to the high solid resin, compares with the conventional resin of low solid, and it has reduced the volatile quantity of solvent, relatively compliance with environmental protection requirements.In order to obtain high solids content; Developed low-molecular-weight methyl butyl complex etherified melamine formaldehyde resin; And through changing the application of baking-curing condition acquisition in industry, the methyl butyl complex etherified melamine formaldehyde resin of haplotype is widely accepted as linking agent.

Coating system with high crosslink density carries out recoat on the coating after the baking be unusual difficulty, because there is not the treated part of having resinized can not effectively improve ply adhesion.Yet coating is because a variety of causes recoat is again inevitable; For example at this moment the two tone colour on automobile, has been coated with the coating of first kind of color on the automobile; After its oven dry; Need then to hide the color of first kind of coating,, then need to smear on the automobile not covered place and make it curing with the coating of second kind of color as not hiding fully with the coating of second kind of color.Compare with the HMMM cross-linking system of high solid, the methyl butyl complex etherified melamine formaldehyde resin linking agent can significantly improve two be coated with interlayer sticking power, address the above problem.

The methyl butyl complex etherified type melamine resin that the exploitation high solid coating is used; The aim at initial stage is to solve in the electrophoretic paint and the inconsistent problem of matrix resin electrodeposition rate; Found afterwards that the matrix resin that this resinoid coatings formulated and polarity differ bigger had fabulous consistency, thus with base material be coated with interlayer outstanding sticking power arranged, smear smooth; Few quick-fried bubble and shrinkage cavity phenomenon of occurring improved the technology stability in the coatings decoration process greatly.

At present; Many formalin or the Paraformaldehyde 96s with 55% of the above-mentioned production of resins technology of external report are starting material; Because these starting material are not production domesticization still; Therefore, need seek to develop the approach of methyl butyl complex etherified melamine formaldehyde resin with domestic raw material (37 weight % formalin).Simultaneously, for overcoming the influence of excessive water to level of response, the present inventor has designed twice etherification technology and has solved this problem.

Summary of the invention

As stated; The objective of the invention is expectation and can adopt domestic raw material, promptly 37 weight % formalins prepare methyl butyl complex etherified melamine formaldehyde resin, simultaneously; In order to solve the influence of excessive water to level of response; Specially designed twice etherification technology, the excellent in stability of this synthesis technique, the quality of the synthetic resins that obtains meets the requirements.

Another object of the present invention provides a kind of optionally an acidic catalyst (tosic acid-butanol solution), and it can make ether exchange reaction carry out smoothly, and the xanthochromia reaction can not take place.

The present invention is such realization, and it aims to provide a kind of preparation method of methyl butyl complex etherified melamine formaldehyde resin, it is characterized in that, in weight percent, the composition for preparing this terpolycyantoamino-formaldehyde resin comprises:

37% formaldehyde solution: 20%-30%;

Trimeric cyanamide: 10%-25%;

Methyl alcohol: 20%-50%;

Butanols: 20%-50%.

The principle of the invention is that trimeric cyanamide and formaldehyde pass through hydroxymethylation, and methyl-etherified reaction and ether exchange reaction generate methyl butyl complex etherified melamine formaldehyde resin.Principal character is to have used tosic acid-butanol solution as catalyzer, makes ether exchange reaction smooth.At this moment, use catalyzer tosic acid-butanol solution in the concentration of tosic acid be 0.3～0.7 weight %.Alkali and the sour pH value of adjusting reactive system have been adopted in the reaction process, so as to the control speed of reaction.Described alkali is respectively the sodium hydroxide solution of 30 weight % and the hydrochloric acid soln of 37 weight % with acid.

Whole preparation method comprises the following steps:

(1) trimeric cyanamide, 37% formaldehyde solution are dropped in the reaction kettle, add 30 weight % sodium hydroxide solutions and regulate pH=8～12, stir and heat up, under 50～80 ℃ temperature, reacted 1～3 hour;

(2) reaction product is cooled to 35～55 ℃, adds methyl alcohol and 37 weight % hydrochloric acid solns, regulates pH=2～5, reacts 1～2 hour;

(3) add 30 weight % sodium hydroxide solutions, behind adjusting pH=8～12, underpressure distillation;

(4) reaction product is cooled to 35～55 ℃, adds methyl alcohol and 37 weight % hydrochloric acid solns, regulates pH=2～5, reacts 1～2 hour;

(5) add 30 weight % sodium hydroxide solutions, behind adjusting pH=8～12, underpressure distillation;

(6) add butanols and tosic acid, regulate pH=2～5, be warmed up to 80～120 ℃, reacted 1～2 hour;

(7) add 30 weight % sodium hydroxide solutions, regulate pH=8～12, underpressure distillation is filtered, and promptly gets methyl butyl complex etherified melamine formaldehyde resin.

Advantage of the present invention is conspicuous; At first, what it adopted is the raw material (37 weight % formalin) of production domesticization, secondly; The temperature of controlling in the whole preparation feedback process is all lower; And the solids content of the resin that makes reach 99 weight % and more than, moreover, have very high sticking power with this resin coatings formulated.

Embodiment

Below in conjunction with embodiment the present invention is further specified, but the present invention never is confined to these embodiment.Below per-cent in each example all refer to weight percent.

Embodiment 1

Trimeric cyanamide 30g, 37% formaldehyde solution 102g are dropped in the reaction kettle, add 30% sodium hydroxide solution, regulate pH=10, stir and heat up, reaction is 2 hours under 65 ℃ temperature; Be cooled to 45 ℃, add methyl alcohol 99g and 37% hydrochloric acid, regulate pH=4, reacted 1 hour; Add 30% sodium hydroxide solution, regulate pH=10, underpressure distillation; Be cooled to 45 ℃, add methyl alcohol 70g and 37% hydrochloric acid, regulate pH=2, reacted 1.5 hours; Add 30% sodium hydroxide solution, regulate pH=10, underpressure distillation; Add butanols 120g and tosic acid 0.6g, be warmed up to 100 ℃, kept 1 hour; Add 30% sodium hydroxide solution, regulate pH=10, underpressure distillation is filtered, and promptly gets methyl butyl complex etherified melamine formaldehyde resin.

Embodiment 2

Trimeric cyanamide 50g, 37% formaldehyde solution 80g are dropped in the reaction kettle, add 30% sodium hydroxide solution, regulate pH=9, stir and heat up, reaction is 3 hours under 50 ℃ temperature; Be cooled to 35 ℃, add methyl alcohol 138g and 37% hydrochloric acid, regulate pH=4, reacted 3 hours; Add 30% sodium hydroxide solution, regulate pH=10, underpressure distillation; Be cooled to 35 ℃, add methyl alcohol 114g and 37% hydrochloric acid, regulate pH=2, reacted 1 hour; Add 30% sodium hydroxide solution, regulate pH=10, underpressure distillation; Add 180g butanols and tosic acid 1g, be warmed up to 120 ℃, kept 1 hour; Add 30% sodium hydroxide solution, regulate pH=10, underpressure distillation is filtered, and promptly gets methyl butyl complex etherified melamine formaldehyde resin.

Embodiment 3

Trimeric cyanamide 40g, 37% formaldehyde solution 95g are dropped in the reaction kettle, add 30% sodium hydroxide solution, regulate pH=8, stir and heat up, reaction is 1 hour under 80 ℃ temperature; Be cooled to 55 ℃, add methyl alcohol 125g and 37% hydrochloric acid, regulate pH=2, reacted 2 hours; Add 30% sodium hydroxide solution, regulate pH=12, underpressure distillation; Be cooled to 35 ℃, add methyl alcohol 92g and 37% hydrochloric acid, regulate pH=4, reacted 2 hours; Add 30% sodium hydroxide solution, regulate pH=12, underpressure distillation; Add 160g butanols and tosic acid 0.9g, regulate pH=3, be warmed up to 110 ℃, kept 2 hours; Add 30% sodium hydroxide solution, regulate pH=11, underpressure distillation is filtered, and promptly gets methyl butyl complex etherified melamine formaldehyde resin.

The basic mechanical design feature measured value of embodiment 1～3 gained methyl butyl complex etherified melamine formaldehyde resin product is as shown in table 1.The all properties index all meets the requirements.

The methyl butyl complex etherified melamine resin of embodiment 1 gained cooperated the system lacquer with vibrin after, compare with the HMMM cross-linking system of high solid, its performance comparison is as shown in table 2.

Table 1

Project	Require index	Embodiment 1	Embodiment 2	Embodiment 3
					25 ℃ of viscosity (Pas)	1.4～5.5	1.5	5.5	4.2
Solid, %	≥98	99.2	99.0	98.9
					Acid number, mgKOH/g	≤1	≤1	≤1	＜1
Color and luster number	≤1	≤1	≤1	≤1

Table 2

Can find out by table 2: coating characteristic such as hardness, snappiness etc., two kinds of linking agents are identical, but there is gap in coating adhesion.By the methyl butyl complex etherified melamine formaldehyde resin cross-linking system of the present invention's preparation, sticking power can reach 1 grade, and common methyl-etherified melamine formaldehyde resin can only reach 3 grades.The experiment of a large amount of sticking power shows that the hexamethoxymethyl melamine resin is coated with the sticking power completely dissolve of interlayer as first, second of linking agent, and methyl butyl complex etherified melamine formaldehyde resin has excellent adhesion.The first coating storing temperature to 175 ℃ even raise, to the influence of the enamelled coating sticking power of methyl butyl complex etherified melamine formaldehyde resin cross-linking system also very a little less than.

Claims (1)

1. the preparation method of a methyl butyl complex etherified melamine formaldehyde resin is characterized in that, in weight percent, the composition for preparing this terpolycyantoamino-formaldehyde resin comprises:

37% formaldehyde solution: 20%-30%;

Trimeric cyanamide: 10%-25%;

Methyl alcohol: 20%-50%;

Butanols: 20%-50%;

Adopt tosic acid-butanol solution as catalyzer, the concentration of tosic acid is 0.3～0.7 weight % in described catalyzer tosic acid-butanol solution; In the preparation feedback process of resin, adopt the pH value of alkali and acid adjustment reactive system, so as to the control speed of reaction; Described alkali is respectively the sodium hydroxide solution of 30 weight % and the hydrochloric acid soln of 37 weight % with acid;

Said preparation method comprises the following steps:

(1) trimeric cyanamide, 37% formaldehyde solution are dropped in the reaction kettle, add 30 weight % sodium hydroxide solutions and regulate pH=8～12, stir and heat up, under 50～80 ℃ temperature, reacted 1～3 hour;

(2) reaction product is cooled to 35～55 ℃, adds methyl alcohol and 37 weight % hydrochloric acid solns, regulates pH=2～5, reacts 1～2 hour;

(3) add 30 weight % sodium hydroxide solutions, behind adjusting pH=8～12, underpressure distillation;

(4) reaction product is cooled to 35～55 ℃, adds methyl alcohol and 37 weight % hydrochloric acid solns, regulates pH=2～5, reacts 1～2 hour;

(5) add 30 weight % sodium hydroxide solutions, behind adjusting pH=8～12, underpressure distillation;

(6) add butanols and tosic acid, regulate pH=2～5, be warmed up to 80～120 ℃, reacted 1～2 hour;

(7) add 30 weight % sodium hydroxide solutions, regulate pH=8～12, underpressure distillation is filtered, and promptly gets methyl butyl complex etherified melamine formaldehyde resin.