FI64624C - FORMALDEHYD CHEMICAL BINDANDE AEMNESKOMPOSITION SOM APPLICERAS PAO YTAN AV ETT STYCKE - Google Patents

Description

1 64624

This invention relates to a formaldehyde chemically binding composition to be applied to the surface of a body. The invention further relates to the use of such a composition of matter as a smoothing agent, paint or wallpaper adhesive.

When present in high concentrations in the air, formaldehyde is a harmful compound. The maximum permissible formaldehyde concentration in the workplace air has been set at 1 mg / m in several countries. Since 1 January 1983, the Finnish Medical Board has set a maximum limit of 0.15 mg / m for formaldehyde in the air of new homes. Such a low value is due to e.g. that in dwellings, exposure is not limited to fixed working hours and is more common than in the workplace for people sensitive to formaldehyde, such as asthmatics or people with allergies. Indeed, most attention has been paid to form-aldehyde disadvantages in new homes, where the emission has often been caused by incorrectly manufactured or used chipboard. It should be noted, however, that no particle board meeting the quality standards, when used correctly, has been found to cause problems in this respect.

Urea formaldehyde adhesive or melamine formaldehyde adhesive is usually used in the manufacture of particle board. As such, such an adhesive contains very little free formaldehyde, which, however, is formed in chemical reverse reactions during the curing of the resin. For example, if the curing temperature or the quality or amount of hardener is incorrectly controlled, significantly more phonitaldehyde may be released during curing than normal. From such a board, formaldehyde evaporates into the air over a relatively long period of time and especially in warm interiors where particle board is mainly used. Even good quality particle board should not be used in damp areas, as moisture will gradually release formaldehyde chemically bound to the adhesive. It must also be considered a mistake to paint the unprimed chipboard directly with ordinary latex paints or for wallpapering using ordinary water-based adhesives or pastes. For example, solvent-borne alkyd primers are recommended for priming, and alkyd-coated chipboards are also available at the factory.

Formaldehyde-containing adhesives are used not only in the manufacture of particle board but also e.g. for gluing veneers and for assembling objects in the carpentry industry.

The latest way to prevent the evaporation of formaldehyde is to treat a product containing a formaldehyde-containing adhesive, for example particle board, with a specially developed reactive coating, usually a latex paint, which contains a compound which reacts with formaldehyde at room temperature. the function of the compound is to chemically bind the volatile free formaldehyde from the substrate to the coating.

It is known from DT-AS 1 669 142 to use urea as a formaldehyde binder in latex paint. Particleboard adhesives have used e.g. cyclic ureas, 1-cyclic carboxylic acid amides and cyclic carbamates (Holz als Röh- und Werkstoff, 32 (1974) H. 10, 408). These form N-methylol derivatives with formaldehyde in which the N-hemiacetal bond is not nearly as strong as the N-c bond in amines. This is an acid- or base-catalyzed equilibrium reaction (Textilveredlung 2 (1967) H.10, 745):

^ T-NH + CH 2 O x = * ^: NCH 2 OH

It is therefore an object of the present invention to provide a chemically binding formaldehyde composition for application to the surface of a body which has better efficacy than urea-containing compositions.

3,64624

The main features of the invention appear from the appended claims.

It is known from GB 1 511 248 to add compounds similar to the present invention to coatings, but nowhere is it stated that the intention is to bind the formaldehyde released from the body.

Thus, in accordance with the present invention, it has surprisingly been found that β-aminoalcohol of the general formula? 3 * 4 R containing from about 1 to 10% by weight of primary or secondary amine group, based on dry matter, can be used as a coating material for formaldehyde instead of urea and the like. , - C - C - R, (I) 2 II 5

R1 - NH OH

wherein R 1 -R 8 independently represent hydrogen, lower alkyl, lower hydroxyalkyl, aryl or aralkyl.

Although the composition of the invention reacts basic, like most latex paints, its effectiveness is maintained even when the pH of the solution drops below the nautical point. The variation of the substituents in the (J-amino alcohol) used in the composition of matter according to the present invention also offers excellent possibilities for controlling the solubility properties to suit, for example, alcohol- and hydrocarbon-thinned coatings.

The groups R. | -Rj. in the case of lower alkyl, this is preferably methyl or ethyl. In the case of the groups R.J-R1 - for aryl or aralkyl, this is preferably phenyl or benzyl.

The group R 2 is preferably a hydroxyhydrocarbon such as hydroxymethyl, while R 1 is hydrogen. In this case, the molecule

> l I

- c - c - c - i i i

HO NH2 OH

can bind two molecules of formeldehyde.

The reactions of carboxylic compounds and said β-amino alcohols have been studied e.g. M. Senkus (Journal, of the American Chemical Society, 67 (September 1945), 1515-9). He has shown that instead of N-methylation, water is cleaved in the reaction to form the following five-ring structure:

Il I t R - C - C - - C - C - + H20 \ C = o + '' '' h / - nh oh nh o \ / c r '\

When applied to formaldehyde, this means that the reaction products are obtained

. . . . I

-c-c- -c-c-c-

- N 0 or 0s Λ P

CH2 ^ 2 ^ 2

In classical synthesis, aldehyde and β-amino alcohols are reacted, for example, in boiling benzene to remove the water formed as an azeotrope with a solvent. When using the composition of matter according to the invention, this reaction takes place at room temperature inside the coating film. The potency is essentially based on the fact that formaldehyde evaporates slowly from the medium (often over many months) and that at a given point in time the amount is small compared to the amount of B-amino alcohol. Depending on the formaldehyde emission, said (J-amino alcohol in the composition according to the invention is preferably 1 to 10% by weight of the coating. At least some of the groups R1 to R5 should preferably be other than hydrogen atoms so that the compound is sufficiently volatile and retains its effectiveness the reaction products are typically high molecular weight compounds that remain part of the coating.

Chemically binding formaldehyde-containing β-amino alcohols containing a primary or secondary amine group for use in the composition of the invention can be prepared by known methods, e.g. from the corresponding nitroalcohol by hydrogenation. Many of these compounds are known mainly as starting materials for 5,64624 syntheses. On the other hand, their use in formaldehyde chemically binding compositions applied to the surface of a body has not been previously reported in the literature.

The invention is described in more detail below by means of examples. Example 1

The formaldehyde binding capacity of the following compounds of the invention was compared using urea as a reference compound: A = 2-amino-2-methyl-1,3-propanediol B = 2-amino-1-phenyl-1,3-propanediol C = 2-benzylaminoethanol D = 6- ethanolamine,.

E = 2-amino-1-butanol

A sample solution of ethanol was prepared containing 1 g of CH 2 O / liter of solution. A 5 ml sample of this solution was taken in a 250 ml Rotavapor flask. The flask was sealed and connected to an air flow line with a flow meter on the supply air side (control 10 1 / h), a wash bottle filled with granular activated carbon, and a CaCl 2 tube closest to the flask. On the exhaust air side, there were first two wash bottles, each containing 100 ml of distilled water. Air was allowed to flow through a rotating flask in a heat bath (temperature 30 ° C) for 6 hours. After the experiment, the water samples in the wash flasks were combined, diluted to 250 ml and mixed. A 5 ml sample of the solution was taken, to which 2 ml of 10% chromotropic acid and 26 ml of concentrated sulfuric acid were added. The assay was then continued by measuring the formaldehyde content spectrophotometrically against standard solutions (guide: Journal of Coatings Technology, 52 (1980) No. 668, 49-54).

A similar assay was then performed on solutions to which formaldehyde-binding compounds were added in 2% by weight of the solution. The results are compared with the initial formaldehyde content as follows: 6 64624 Determined CH 2% by weight 1. Without addition 90 2. Urea 82 3. Compound A | 40 4. "b / 2 Weight“% 11 5. "C 4 6." D 33 7. "eJ 45

Example 2

Solution 4 was neutralized with paratoluenesulfonic acid. The pH measured from the ethanol solution then decreased from 10.6 to 6.3. A formaldehyde assay similar to Example 1 was performed to give 21% by weight.

Example 3

A silo (spatula, dry matter content 75% by weight) was prepared containing latex 25% by weight, titanium dioxide 15% by weight, filler 45% by weight, additives such as thickener, wetting agent and defoamer a total of 5% by weight and water 10% by weight. -%. The following reactants with formaldehyde were added to this smoothing. The following paints were obtained:

Silote 1: does not contain a reactive substance

Silote 2: contains 5% by weight of urea

Silote 3: contains 2% by weight of 2-amino-2-methyl-1,3-propanediol

Silote 4: contains 2% by weight of 2-amino-2-methyl-1,3-propanediol and 5% by weight of urea.

Em. the inserts were each coated with 4 pieces of chipboard measuring 40 cm x 60 cm and 12 mm thick. The application rate was 125-135 g / m 2. In addition, 4 unprocessed particle boards were taken. All plates in the example were from the same batch. The edges of the plates were protected with a tight layer of paint and the plates were placed in metal 0.12 m metal boxes with a ventilation coefficient of 0.5 h ~ ^.

The air temperature was 20 ° C and the humidity was 85% RH. The test plates were allowed to equilibrate for 7 days, after which the formaldehyde content of the box air 7 64624 was determined according to standard SFS 3862.

The following results were obtained:

Uncoated sheet 0.99 mg / m 2

Silote 1 0.96 mg / m

Silote 2 0.35 mg / m · *

Silote 3 0.14 mg / m 2

Silote 4 0.08 mg / m

Thus, the substance according to the invention achieved a better result than urea, although the amount of urea was higher. The combination of urea and the substance according to the invention gave the best result.

A good and even coating was obtained with all substances and amounts. The application took place on a roller and the drying was carried out in an infrared oven for one minute, after which the coating was completely dry.

Example 4

A paint (dry matter content 55% by weight) was prepared containing latex 35% by weight, titanium dioxide 20% by weight, filler 15% by weight, additives such as thickener, wetting agent and defoamer a total of 5% by weight, and water 25% by weight. %. Various amounts of 2-amino-2-methyl-1,3-propanediol were added to this paint. The following paints were obtained:

Paint 1: does not contain a reactive substance

Paint 2: contains 0.5% by weight of reactive substance

Paint 3: contains 1.0% by weight of reactant

Paint 4: contains 5.0% by weight of reactant.

Each of these paints was painted 4 pieces of chipboard measuring 40 cm x 60 cm and 12 mm thick. The plates were from the same batch. The average application rate of the paint was 200 g / m 2. The edges of the plates were protected with a dense layer of paint and tested as in Example 3. The following results were obtained: 8 64624 3

Uncoated plate 2 »20 mg / m

Paint 1 0.29 mg / m 2

Paint 2 0.06 mg / m 2

Paint 3 0.02 mg / m

Paint 4 0.02 mg / m3

All paints gave a good and uniform coating. Application was by brush and drying was performed at room temperature.

Claims (5)

64624 Patent Claims 1. A composition for chemically binding formaldehyde to be applied to the surface of a body, characterized in that it contains from about 1 to 10% by weight, based on dry matter, of a β-amino alcohol having a primary or secondary amine group of the general formula: * 3 * 4 r2 - C - C - R 5 (i) R 1 to NH OH independently of one another are hydrogen, lower alkyl, lower hydroxyalkyl, aryl or aralkyl. Composition according to Claim 1, characterized in that R 1 is H and R 2 is hydroxymethyl. Composition according to Claim 1, characterized in that R 1 is benzyl. Composition according to Claim 1, characterized in that at least one of the groups R 1 -R 2 is present. is other than hydrogen. 5. A β-amino alcohol having a primary or secondary amine group of the formula R3 R <R, - C - C - R- 2. i 5 R1 - NH OH, independently of one another, denoting hydrogen, lower alkyl, lower hydroxyalkyl, aryl or Aral rabbits, for use as a chemical binder in formaldehyde, in paints, paints or wallpaper adhesives.