CS236649B1 - Complex hardener for coating compositions and method of its preparation - Google Patents

Abstract

The subject of the invention is a complex curing agent for paints containing at least one a strong inorganic compound and / or organic acid and ammonia, respectively. his organic or inorganic derivatives, which is prepared by the reaction of strong inorganic and / or organic acids in the form of solutions of p- toluenesulfonic, hydrochloric, phosphoric with ammonia and / or its compounds and derivatives such that per mole of strong acid 0.01 to 2 moles of the amino compound are used

Description

The invention provides a complex hardener for paints containing urea-formaldehyde and / or melamine-formaldehyde condensates and a process for its preparation.

Paints containing urea-formaldehyde and / or melamine-formaldehyde condensates smell of free unreacted formaldehyde. In addition to the unpleasant irritating odor of formaldehyde, the fact that formaldehyde is a protoplasmic poison affecting the nervous system, internal and external organs, bronchi, mucosa, nasopharynx, conjunctival conjunctiva and the like (N. L. Lazarev: Chemical Poisons in Industry I, Prague 1959) also stands out. In addition, in particular, recent reports have been reported to cause mutagenicity and carcinogenicity in experimental animals (Blackwell M., Kang A., Thomas A., Infante P., Am. Ind. Hyg. Assoc. J. 42, 7, A34, A36, A38, cited CA 95, 109 483xj.

The mentioned paints are of many kinds and differ in the content of urea-formaldehyde resp. melamine-formaldehyde condensates, alkyd esters, unsaturated oils, organic solvents, admixtures of pigments, dyes, wetting agents, luster or matt coatings and the like (L. M. Lvovich: Zbornik techničeskych uslovij na lakokrasočnye material, Izdatel71, Izdatelstvo 19, Izdatel.

While the paints are still at ordinary temperatures for several months, after their application, the hardening of the lacquers is accelerated by the addition of strong organic or inorganic acids.

As hardeners, respectively. lacquer washes are used, in particular, solutions of hydrochloric acid, p-toluenesulfonic acid, phosphoric acid, with water and / or organic solvents with butyl alcohol, butyl acetate, ethyl glycol, butyl glycol and the like. (H. F. Payne: Technology of Organic Coverage, G. Ch. I., Leningrad 1959).

Although these hardeners fully meet the requirements for rapid drying and hardening of the paint, they do not affect the amount of formaldehyde released.

This drawback is solved comprehensively by a hardener for paints containing urea-formaldehyde and / or melamine-formaldehyde condensates, which contains at least one compound of strong inorganic and / or organic acid and ammonia, respectively. organic or inorganic derivatives thereof, the amino group content of the hardener being 0.5 to 10% by weight. %, preferably 3 to 5 wt.

According to the present invention, the process for the preparation of a complex hardener for paints is carried out by reacting strong inorganic and / or organic acids, optionally in the form of solutions in particular p-toluenesulfonic acid, hydrochloric acid, phosphoric acid with ammonia and / or its compounds and derivatives. The composition of claim 1, wherein 0.01 to 2 moles of the amino compound is used per mole of strong acid.

The advantage of using the complex hardener according to the present invention is that, with the curing properties not impaired, it also has a substantial effect on the reduction of the formaldehyde released from the cured paint. In addition to this, it is also important that said hardener has reduced to suppressed corrosion properties on the material, and also that the hardener has a reduced effect on the human organism.

Said hardener can be used as before, i. j. % at a concentration of 5 to 10 wt. for paint.

Its preparation is simple, since it is practically the neutralization of a strong organic and / or inorganic acid, most often in the form of dilute solutions of 10 to 40% by weight. either gaseous ammonia or aqueous solutions thereof, optionally by addition of ammonia salts e.g. formate, acetate, carbonate to acids. In this case, the reaction is not as violent as neutralization. In some cases, when the previously described hardeners are used to prepare the hardener of the present invention, it may be that we do not use sufficiently pure chemicals containing iron salts and the like. when the solutions are neutralized and made alkaline, ferric hydroxide or other transition metal hydroxides are precipitated in an alkaline medium, which should be removed either by filtration, sedimentation or similar separation operations prior to use.

It is interesting to note that although these are acid-curable lacquers, hardeners due to low moles. The weight of the amino group may be acidic, neutral or even basic, but this does not adversely affect the drying time of the paint. E.g. in Example 1 in Tab. 1 of said complex hardener in line 4 to 6; 10 to 12; 16-18; 22-24 are alkaline 26, 27, 29 and 32 lines acidic and the like. Due to the economics of preparation, the use of ammonia, resp. its hardener salts.

The amino group content of the hardener is not random, but should be selected such that its content, when using the necessary amount of hardener to the paint, is about 0.66 mol per mole of free formaldehyde in the paint to be treated.

Since the coating compositions according to the method of use have about 0.6% by weight. free formaldehyde in conventional types, respectively. 1.7 wt. for Stabil types, the amount of amino groups per coating material used would be 0.2 and 0.55% by weight. This means using 7 wt. hardener for paints content of amino groups 2.8 to 7.7 pens. wt. etc.

Further advantages as well as the way of use can be seen from the following examples.

238649

Example 1

The addition of an aqueous solution of p-toluenesulfonic acid, i. j. concurrently used paint hardeners and modified hardeners according to the present invention for the free formaldehyde content and drying temperature for various types of dust-resistant paints. The test results are summarized in Table 1.

Table 1

Effect of hardener type on formaldehyde content and drying time.

Type of paint 1 hardener Contents free formaldehyde benzaldehyde (% by weight) 4 Drying time at 25 ° C (min) 5 remark 6 Quantity per paint (% by weight) 2 Quantity and type of ingredients (% by weight) in water as solvent 3 S 1708 10 5% pTSK 1.46 90 PTTA-parato- S 1708 10 10% pTSK 1.49 60 toluenesulphonic S 1708 10 20% pTSK 1.51 50 acid conc. condition S 1708 10 5% pTSK + 5% NH 3 0.44 30 New blend S 1708 10 10% pTSK + 5% NH 3 0.46 50 hardener ZT — 1 S 1708 10 20% PTTA + 5% _NH3 0.34 37 ZT-2 HT-3 S 1711 10 5% pTSK 0.69 20 building type S 1711 10 10% pTSK 0.69 21 - hardeners S 1711 10 20% pTSK 0.71 20 S 1711 10 5% + 5% PTTA _NH3 0.08 7 New blend S 1711 10 10% PTTA + 5% _NH3 0.08 7 hardener S 1711 10 20% pTSK + 5% NH 3 0.15 8 SH 20.16 GDR 10 5% pTSK 0.51 10 Present SH 20.16 GDR 10 10% pTSK 0.58 8 hardeners SH 20.16 GDR 10 20% pTSK 0.63 8 SH 20.16 GDR 10 5% + 5% PTTA _NH3 0.0 7 New com- SH 20.16 GDR 10 10% PTTA + 5% _NH3 0.03 7 plexic hardeners SH 20.16 GDR 10 20% PTTA + 5% _NH3 0.1 6 S 5057 10 5% pTSK 0.47 11 Present S 5057 10 10% pTSK 0.51 11 hardeners S 5057 10 20% pTSK 0.61 11 S 5057 10 5% + 5% PTTA _NH3 0.06 9 New com- S 5057 10 10% pTSK + 5% NH ₃ 20% pTSK + 5% NH ₃ 0.07 10 plexic hardeners S 5057 10 0.08 8 S 1708 10 75% hardener S 6707 + + 25% NH ₃ (25% solution) 0.40 55 NH ₃ - as a 25% solution S 1708 10 S 6707 + 5% urea 1.43 46 S 1708 10 S 6707 + 10% urea 1.35 - S 1708 10 S 6707 + 20% MEA 1.05 - MEA-mono- ethanolamine S 1708 10 S 6707 + 25% urea 0.70 40 S 1708 10 S 6707 + 40% MEA 0.71 60 darkened S 1711 10 S 6707 + 40% MEA 0.04 25 darkened S 1711 10 S 6707 + 25% urea 0.21 20 S1708 ' 10 The 6718 + 60% NH ₃ (8%) 0.83 70 S 1711 7 The 6707 + 25% _NH3 (25%) 0.06 10 S 1711 7 N 6718 + 60% NH ₃ (8 ° / o) 0.43 20 S 5057 7 The 6707 + 25% _NH3 (25%) 0.10 10 S 5057 7 The 6718 + 60% NH ₃ (8%) 0.26 12 SH 20.16 7 The 6707 + 25% _NH3 (25%) 0.06 5 SH 20.16 7 The 6718 + 60% NH ₃ (8%) 0.24 10

Example 2

For hardening of paints S 1708, S 1711, SH 20.16 and S 5057, mixed hardeners are prepared by adding to the hardeners S 6718, S 6707 various amounts of ammonia or ammonia, respectively. amine compounds and then the mixture is applied to the coating compositions. Drying is understood to be a psychological dust, Stage A according to ČSN 67 3053.

Hardener I.

Prepared by mixing 25 wt. hardener S 6718, 25 wt. % ammonia solution (25% in water) and 50% wt. distilled water. The turbidity is likely to be filtered off before use. Application tests of hardener I. (T. - I):

S 1708 + 10 wt. T.-I; fd content - 0.7 pere. materials .; drying 95 min.

S 1711 + 7 ° / wt. T.-I; fd - 0.25% by weight; drying 25 min.

SH 20.16 + 7 wt. T.-I; fd - 0.25 pere. materials .; drying 16, min.

S 5057 + 7 wt. T.-I; fd - 0.15% by weight; drying 10 min.

Hardener II.

Prepared by mixing 80 wt. hardener S 6707 and 20 wt. 25% ammonia solution (ammonia water)

Application of hardener II (T. - II)

S 1708 + 10% T. - II-formaldehyde 1.0% by weight, drying 80 min.

Hardener IV.

A mixture consisting of 30 wt. S 6718; 20% (25% solution) ammonia, 50% water by weight after filtration for 20 min.

Application of hardener IV.

S 1708 + 10 0 wt. Τ-IV; fd 0.84% by weight, drying 80 min.

Tužidlo V.

The mixture consisted of 85 wt. S 6707 and 15 wt. 25% ammonia solution. Application of hardener V.

S 1708 + 10 wt. T.-V; formaldehyde content 0.95, drying 90 min.

Hardener G

Hardener prepared from 10 wt. % ammonium chloride, 10 wt. water, 60 wt. % methanol and 20 wt. ammonia water (25 pere).

Application of hardener G

S 1708 + 10 wt. G, formaldehyde 0.42 why. weight, drying 85 min.

S 1711 + 7 wt. G, formaldehyde 0.1% by weight, drying 20 min.

S 5057 + 7 wt. G, formaldehyde 0.02 wt.%, Drying for 17 min.

Hardener H

Mixture 10% w / w p-toluenesulfonic acid, 14 wt. water, 50 wt. % methanol, 25 wt. % ammonia (25% aqueous solution) 1 wt. phosphoric acid.

The mixture was filtered (about ferric hydroxide) H.

Application of hardener H

S 1711 + 7 wt. H; formaldehyde 0.1% by weight, drying 20 min.

S 5057 + 7 wt. H; formaldehyde 0.01; drying 15 min.

Hardener Ch

% 1 wt. p-toluenesulfonic acid, 15 wt. water, 50 wt. methanol, 25 wt. ammonia (25% aqueous solution).

Application after precipitate filtration (alkaline)

S 1711 + 7 wt. ch; formaldehyde 0.12 pere. wt., drying 15 min.

S 5057 + 7 ° / wt. ch; formaldehyde 0.02 pere. wt., drying 15 min.

Hardener I

20% wt. % p-toluenesulfonic acid, 20 wt. % ammonia water, 60 wt. methanol.

S 1711 + 7 wt. I; formaldehyde 23% by weight, 20 min. Drying

S 5057 -I 7 wt. I; formaldehyde 0.07 pere. weight, 15 min. drying Hardener J

To the hardener S 6718 was added a 60% solution of ammonium acetate in water in an amount of 25 washes. wt. hardener (ammonium acetate was prepared by mixing 11.7 g acetic acid j and 13.3 g 25% aqueous ammonia). Application of hardener J

Paint S 1707 + 10% wt. hardener J mixed for 10 min; determined formaldehyde 0.57 pere. wt., drying 70 min.

Paint S 1711 + 7% wt. hardener J mixed for 10 min; determined formaldehyde 0.15% by weight, drying for 20 min.

Hardener K

25% w / w is added to the hardener S 6707. 55 pere. aqueous ammonium formate solution (prepared by mixing 10.95 g of 99% formic acid and 16.4 g of 25% aqueous ammonia).

Application of hardener K

Paint S 1708 + 10% wt. hardener K mie236649 10 min. determined formaldehyde 0.55 why. weight, drying 72 min.

Paint S 1711 + 7% wt. hardener K mix 10 min. determined formaldehyde 0.12% by weight; drying time 14 min.

Claims (2)

Complex hardener for paints containing urea-formaldehyde and / or melamine-formaldehyde condensates, characterized in that it contains at least one compound of a strong inorganic and / or organic acid and ammonia or its organic or inorganic derivatives, the amino group content of the hardener being 0, 5 to 10 wt.%, Preferably 3 to 5 wt. INVENTION 2. A process for the preparation of a complex hardener for paints according to claim 1, characterized in that it is prepared by reacting strong inorganic and / or organic acids, optionally in the form of solutions, in particular p-toluenesulfonic acid, hydrochloric acid, phosphoric acid with ammonia and / or its compounds. and derivatives, wherein from 0.01 to 2 moles of amino compound is used per mole of strong acid.