CN1640907A

CN1640907A - Low formaldehyde melamine adhesive with expanding characteristic and preparation method

Info

Publication number: CN1640907A
Application number: CN 200410013517
Authority: CN
Inventors: 倪卓
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-01-14
Filing date: 2004-01-14
Publication date: 2005-07-20

Abstract

The melamine resin prepared with formaldehyde and melamine as main material and in the presence of Lewis acid or alkali has free formaldehyde content of about 0.1 %. The adhesive possesses excellent expansion performance during formation and is suitable for use in producing various kinds of board. The products with the adhesive have low formaldehyde release amount, excellent mechanism performance, excellent weather resistance, etc. The liquid resin may be spray dried to prepare melamine adhesive powder capable of maintaining reaction activity for long time. The adhesive of the present invention has no need of adding formaldehyde trapping agent.

Description

Low formaldehyde has the melamino-formaldehyde tackiness agent and the manufacture method thereof of expansion character

1, technical field

The invention discloses the preparation method of a kind of preparation, can be used for forming the mechanicals of formaldehyde release with qualification based on the water-based low content of free formaldehyde melamine resin of trimeric cyanamide and formaldehyde; Because this tackiness agent has the marked inflation performance when solidifying, therefore be particularly useful for producing all kinds of board product, as sawdust-board, fiberboard and adhesive plate.Through the powder melamine resin of super-dry spray art preparation, kept the feature of liquid melamine resin, also have excellent storge quality.

2, technical background

Advantages such as the melamine resin adehsive stick is widely used in many fields of industry and life, and melamine resin has possessed with low cost, and reactivity worth is good, easy to process.In process of production, by adding catalyzer (hardening of resin agent), the curing speed of resin can be regulated, and therefore, throughput increases considerably, and the work period shortens.Yet, use the melamine resin adehsive stick to invariably accompany and discharging during the processing of goods and in the goods use and the generation formaldehyde gas.In use, it is to have free formaldehyde in the trimeric cyanamide tackiness agent that formaldehyde discharges on the one hand, is present in the article construction with the form of gas, and is dissolved in the contained water of goods.Simultaneously, melamine resin contains methylol, methylene ether bridge and other reaction product, and they can hydrolysis return formaldehyde.Not completely crued resin (methylolurea) and resin degraded (hemiacetal, ether and methylol) have increased the burst size of formaldehyde.Formaldehyde is a kind of toxic substance, and irritating smell is arranged, and to nasal mucosa, the retina and the upper respiratory tract all have hormesis, can cause dermatitis.It can generate aminocompound with the proteins react in the human body, thereby changes protein properties, impairs one's health.In addition, formaldehyde can cause chronic poisoning, pathology and anaphylaxis.Therefore, in all types of industries goods, burst size of methanal is should a strict standard of controlling.

The control of melamine resin goods burst size of methanal mainly contains two kinds of methods:

(1) the ear ratio that rubs of control formaldehyde trimeric cyanamide.Reduce the ear ratio that rubs, can reduce the content of free formaldehyde effectively.Rub ear than low, the water-soluble decline of resin, stability in storage is low, and set time is long; Reduce mol ratio, reduced the sclerosis network and got the degree of branching and degree of crosslinking, this just inevitably cause degradation under the bonding strength (USP-4968772, USP-4968773, GBP-2150939, USP-4410685, USP-4482669, CN-1044481).

(2) use formaldehyde-trapping agent.In formaldehyde trimeric cyanamide reaction later stage and molding process, add formaldehyde-trapping agent, formaldehyde be can reduce effectively and (Chinese patent CN-103438, CN-1262301 discharged, CN-1091632, CN-1304942, CN-1105693, CN-1086224, CN-1104657, CN-1062541).Introduce these additives, the resin cost is improved, and influence the mechanical property and the use properties of tackiness agent and products thereof.

3, summary of the invention

The preparation method who the purpose of this invention is to provide a kind of melamine resin has both the stable characteristics of high-level efficiency, low cost, low content of free formaldehyde and product performance, has eliminated all foregoing problems.

Another object of the present invention provides a kind of melamine resin, and this resin has and is about 0.1% low content of free formaldehyde content, and this resin is very easy to reaction, has eliminated potential Health hazard in the course of processing.

Another purpose of the present invention provides a kind of melamine resin, has the marked inflation performance in the course of processing.Therefore, in the production of all kinds of board product, tackiness agent and bonded material interface performance are good, and mechanical property and use properties are good.

Another purpose of the present invention provides a kind of melamine resin, not only can be liquid form, and can be powder morphology.The powder melamine resin can store for a long time, and keeps excellent reactivity worth.

Another purpose of the present invention provides a kind of melamine resin, be suitable for preparing sawdust-board, fiberboard and glued board class composite prod, the board product of this resins has the 2-15mg/100g burst size of methanal, meets the relevant controlling standard, thereby its final user is safe from harm.This resin has satisfied its whole requirements at aspects such as physical strengths simultaneously.

4, embodiment

Embodiment 1

With the formaldehyde of suitable proportion, trimeric cyanamide and water add reactor, and the ear ratio that rubs of formaldehyde/trimeric cyanamide is 1.5-2.5.Regulate pH value with Lewis base or acid, scope is 8-12.This mixture after 1-2 hour, adds organic class material of 1%-10% 50 ℃-80 ℃ reactions.Continue to be reflected between 50 ℃ to 100 ℃, the time is 2-4 hour.When viscosity during, mixture is slowly cooled off to 30-60cps.PH value can be adjusted between 8.5 to 10 as needs, promptly make melamine resin.

Prepared melamine resin has following typical properties:

Solid content 50%

Viscosity 30-60cps

PH value 9.2-9.7

Proportion 1.22g/ml

Free formaldehyde 0.1%

14 days shelf liveves

Embodiment 2

Melamine resin among the embodiment 1 is sent into the feed pot of spray-drier, liquid glue is sent into the high speed centrifugation atomizer by the speed governing take away pump, be vaporific glue and enter dry king-tower by the warm air beating (180 ℃) of coming from process furnace, moisture in the glue is vaporized rapidly, the part plastic powder falls into drying tower bottom (100 ℃), and the residence time is about 10 seconds.Prepared powder melamino-formaldehyde tackiness agent has following characteristic:

The appearance white powder

Granularity＜80 orders

Moisture content 3%

Apparent density 0.6-0.8

Formaldehyde content 0.3%

1 year shelf lives

Claims

1. terpolycyantoamino-formaldehyde resin that is suitable for being used for producing low content of free formaldehyde, it is characterized in that using formaldehyde/trimeric cyanamide ear ratio that rubs is 1.5 to 2.5, its mixture is under the effect of Lewis base or acid (the pH value scope is 8-12), temperature of reaction is between 40 ℃ to 100 ℃, and the time is 2-4 hour.After reaction 1 hour, add organic class material of 1%-10%.During reaction terminating, resin viscosity is between 30 to 60cps.With the mixture cooling, pH value can be adjusted between 8.5 to 10 then as needs.

With the terpolycyantoamino-formaldehyde resin that makes, the following dry spray art of process: 150 ℃ to 200 ℃ of feeding temperatures, 80 ℃ to 120 ℃ of drop temperatures, can make the powder terpolycyantoamino-formaldehyde resin at 8 seconds to the 15 seconds residence time.

2. described method of claim 1, wherein

(1) formaldehyde/trimeric cyanamide ear ratio that rubs is 1.5 to 2.5

(2) with the pH value of Lewis acid or alkali regulation system, scope is between 8-12.This mixture reaction temperature is carried out condensation between 40 ℃ to 100 ℃, level of response is controlled between the viscosity 30 to 60cps.

(3) this resin solution is cooled to 30 ℃, and its pH value uses Lewis acid or alkali to be adjusted between 8.5 to 10.

(4) the dry spray art of terpolycyantoamino-formaldehyde resin is 150 ℃ to 200 ℃ of feeding temperatures, 80 ℃ to 120 ℃ of drop temperatures, 8 seconds to the 15 seconds residence time.

(5) in reaction process, add organic class material, consumption is 1%-10%.

3. described method of claim 1, this method comprises that initial use concentration of formaldehyde is 30% to 55%

4. the waterborne polymeric solid content that is made by formaldehyde and trimeric cyanamide in the described method of claim 2 is 40% to 70%.

5. the described Lewis acid of claim 2 comprises hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, hydrosulphuric acid, spirit of salt, Hydrogen bromide, aluminum chloride, titanous chloride, iron trichloride, formic acid, acetate, oxalic acid, propionic acid, vinylformic acid, isopropylformic acid, phenylformic acid, terephthalic acid, isopropylformic acid, maleic acid, laurostearic acid, lauric acid, trichoroacetic acid(TCA), toxilic acid, hexahydrobenzene formic acid, barbituric acid, malonylurea, orthoboric acid, ortho-phosphoric acid, methacrylic acid, maleficent acid, Glacial acetic acid, naphthenic acid, picric acid loses resin acid etc.

6. the described Lewis base of claim 2 comprises sodium hydroxide, potassium hydroxide, calcium hydroxide, hydrated barta, magnesium hydroxide, yellow soda ash, ammoniacal liquor, primary amine, secondary amine, tertiary amine, sodium bicarbonate, saleratus, Sodium Hydrogen Carbonate, potassium bicarbonate.

7. described organic class material of claim 2 comprises:

(1) alcohols methyl alcohol, ethanol, ethylene glycol, n-propyl alcohol, Virahol, propyl carbinol, isopropylcarbinol, hexalin etc.

(2) ethers methyl ether, ether, positive propyl ether, n-butyl ether, n-amylether, methyl-phenoxide etc.(3) ketone acetone, butanone, dimethyl diketone, pimelinketone, methyl phenyl ketone etc.

(4) amine aniline, ethamine, ethylnaphthalene amine, thanomin, diethylamine, Isopropylamine, TERTIARY BUTYL AMINE, p-diaminodiphenyl, pentanoic, triethylamine, Tolylamine, the second sulphamide, Diisopropylamine, acrylamide, meta-aminotoluene, methyl ethyl-amine, 2-aminotoluene, 3-monomethylaniline, Ursol D, O-Phenylene Diamine, m-chloro aniline, p-Chlorobenzoic acid amide, p-Nitroaniline is to first p-diaminodiphenyl, aniline hydrochloride, N, the N-Diethyl Aniline, N, N-diethyl p-phenylenediamine, N, N-Diethyl Aniline etc.

8. the dry spray art of the described melamine resin of claim 2 is 150 ℃ to 200 ℃ of feeding temperatures, 80 ℃ to 120 ℃ of drop temperatures, 8 seconds to the 15 seconds residence time.

9. the method for each that requires in the aforementioned right, the melamino-formaldehyde tackiness agent that this method is produced, free formaldehyde content is generally 0.1% less than 0.5%.

10. the method for each that requires in the aforementioned right, this tackiness agent have the marked inflation performance in moulding process.