DE4117841A1 - Fast-penetrating solns. of amino resin, esp. for paper impregnation - contain low-mol. wt. quat. ammonium cpds. with hydroxy-alkyl or amido-alkyl gp. - Google Patents

Abstract

Aq. soln. (I) of amino resin (II) are claimed, contg. 1-35 wt.% low-mol. wt. quat. ammonium cpd. of formula Rn(R')4-nN+ X- (III) (w.r.t. solids content of I); R = 1-8C alkyl substd. with an 0H or amido gp.; R' = 1-8C alkyl or benzyl; X = anion; n = 0, 1, 2, 3 or 4. Pref., n = 1, 2, 3 or 4, and solids content of (I) is 40-70 wt.%. Pref, (III) is N-(2-hydroxyethyl)-trimethyl -ammonium-chloride (IIIA) or -methyl sulphate, in amt. of 5-20 wt.% w.r.t. solids content; (II) are, e.g. UF or MF resins obtd. by known methods. USE/ADVANTAGE - (I) are useful as fast-penetrating impregnating resins for the prodn. of resin-impregnated paper for coating timber materials (claimed). The invention provides resin solns. which penetrate paper rapidly without dilution (contrast prior-art resin solns.), thus enabling increased prodn. rates (for chipboard etc.,); solns. (I) has viscosity 15-150 mPa.s and are stable for 2-20 weeks.

Description

The present invention relates to aqueous resin solutions based on Aminoplast resins containing 1 to 35 wt .-%, based on the solid content, a low molecular weight quaternary ammonium compound of the general my formula I

(R¹ _n R²₄ _-n N⁺) X⁻ (I)

wherein n = 0, 1, 2, 3, 4, R¹ is a C ₁ -C ₈ alkyl radical which carries a hydroxy group or an amido group and wherein R² is a C ₁ -C ₈ alkyl radical or a benzyl radical and X is ^{- represents} the equivalent of an anion.

Furthermore, the invention relates to the use of such resin solutions for Impregnating decorative papers for the coating of wood-based materials.

The penetration behavior of impregnating resin solutions in paper impregnation process is a very important procedural criterion, since the "Driving speed" of the impregnating machine, among others, the Penetra tion behavior of the resin solution is determined. Just "softening" modes fizierungsmittel, which is almost standard today, at least for MF impregnating resins are often used, often cause a strong increase in the Pene tion time, which in turn is a large-scale processing of the resin slows or makes difficult.

Therefore, such substances come the penetration time of a resin solution reduce significantly, for procedural reasons, a large Meaning too. The lower the penetration time of the resin solution, the more more paper webs can be impregnated in the same time unit, since then run the impregnating machine at a higher speed can.

It is well known that the penetration time of an impregnating resin solution can be shortened by dilution with water. The problem is However, that after the impregnation a correspondingly larger amount of Water must be removed during the drying process. This requires, on the one hand a higher energy input, on the other hand, this is an extension caused the dry season, so that the time initially achieved is compensated again.  

In US-A-44 54 199, the production of electrically conductive Paper laminates described in the top layer a Mixture of an impregnating resin with a quaternary ammonium compound is included. As a quaternary ammonium compound are mainly Diallyldimethylammoniumsalze and their polymers used.

US-A-37 55 220 relates to the use of aminoplast resin solutions in Compound with surface-active substances for the production of Pulp materials, where u. a. also used quaternary ammonium salts become.

Object of the present invention was to Amminoplastharzlösungen such to modify it to an improved penetra during the impregnation process show behavior and at the same time have good storage stability.

Accordingly, the resin solutions defined above were found.

As the aqueous resin solutions underlying aminoplast resins come in general condensates of formaldehyde with urea, melamine or other aminoplast formers such as substituted aminotriazines, for example Acetoguanamine or benzoguanamine.

For example, urea-formaldehyde condensates with moles may be used from urea to formaldehyde in the range of 1: 1 to 1: 2.2 become.

Furthermore, melamine-formaldehyde condensates with molar ratios are suitable from melamine to formaldehyde from 1: 1.3 to 1: 2.5. It can also be melamine Urea mixed condensates are used.

The preparation of such aminoplast resins is known per se. So can For example, melamine-formaldehyde condensates or the corresponding Condensates with urea by condensation of the components in aqueous medium at pH values of 8 to 10 and temperatures of 80 to 100 ° C are produced. Urea-formaldehyde condensates can for example, by condensation of urea and formaldehyde pH values of 4 to 9 and temperatures of 70 to 100 ° C produced become.

It is also possible to use etherified or partially etherified condensates, which can be etherified with C ₁ -C ₄ -alkanols such as methanol, ethanol or butanol by known methods.

The endpoint of the respective condensation reaction can be via the turbidity be determined by 1 g of the reaction mixture with the 5 times the amount of water are added, whereupon the temperature is measured becomes, at which this mixture clouded.

Usually up to clouding temperatures of 40 to 60 ° C. condensed.

In the preparation of the condensates can also conventional modification such as ethylene glycol, diethylene glycol or other polyalcohols such as For example, sugar derivatives or ε-caprolactam in amounts of 2 to 8 wt .-%, based on the solids content, be used.

The preparation of the aqueous resin solutions is advantageously carried out so that Solutions with solids contents of 40 to 70 wt .-% can be achieved. When Solids content is referred to here the dry residue, which determined by placing 1 g of resin solution in a drying oven at 120 ° C for two hours is dried.

As low-molecular quaternary ammonium compounds of the compounds general formula I

(R¹ _n R²₄ _-n N⁺) X⁻ (I)

where n = 0, 1, 2, 3, 4 and R¹ is a C ₁ -C ₈ alkyl radical which carries a functional group such as the hydroxy group or the amido group, wherein the functional group is preferably in end-permanent Position is located. R 2 is a C ₁ -C ₈ -alkyl radical or a benzyl radical.

Preference is given to compounds I in which n = 1, 2, 3, 4.

X ^- stands for the equivalent of an anion. In this case, anions of mineral acids such as halide anions, preferably chloride, nitrate, sulfate, hydrogen sulfate, phosphate, hydrogen phosphate, dihydrogen phosphate come into consideration. Also suitable are alkyl sulfates such as methyl sulfate or ethyl sulfate or alkyl sulfonates such as methyl sulfonate or ethyl sulfonate and arylsulfonates such as toluenesulfonates as anions. Anions of organic acids such as formate, oxalate, acetate or maleate may also be considered.

Preferred ammonium compounds are N- (2-hydroxyethyl) trimethyl ammonium chloride or methyl sulfate.  

Also tetramethylammonium chloride, tetraethylammonium chloride or tetra propylammonium bromide are, for example, suitable quaternary ammonium links.

The low molecular weight quaternary ammonium compounds are erfindungs in amounts of from 1 to 35% by weight, based on the solids content, used, with preferably 3 to 25 wt .-%, particularly preferably 5 to 20% by weight.

The addition of the ammonium compound can be done in several ways. It is possible the ammonium compound already during the condensation of aminoplast resin. But the addition can also be made so that the ammonium compound mixed with a fully condensed resin solution becomes.

Furthermore, the addition but only shortly before processing he follow, by the ammonium compound with the impregnating liquor, so a Aminoplast resin solution already added to hardeners and auxiliaries is mixed.

The aqueous resin solutions according to the invention have solids contents of 40 to 70 wt .-%, at viscosities in the range of 15 to 150 mPa · s (20 ° C). They are clear solutions with a shelf life of 2 to 20 weeks. The Resin solutions of the invention have in the impregnation of decor papers for the production of coated wood materials outstanding penetration behavior, d. H. they penetrate this very quickly to be impregnated paper.

For use as impregnating liquors hardening agents are added to the impregnating resin solutions as is customary. Suitable hardeners are, for example, maleic acid, maleic anhydride, formic acid, ammonium sulfate, ethanol amine hydrochloride, and hardener combinations such as morpholine / p-toluenesulfonic acid, N-methyl-ethanolamine / SO ₂ or N-methylethanolamine / ethanolamine / SO ₂ into consideration.

The hardeners can be used in amounts of from 0.2 to 2% by weight, based on the impregnation resin solution, with the skilled person being aware of how he used the Hardener dosage to the respective application requirements it can match the reactivity of the impregnating resin / hardener mixtures Adjust accordingly by measuring turbidity times and gel times can.  

Furthermore, the impregnating fleets can also use auxiliary equipment such as net be added medium.

Suitable wetting agents include, for example, nonionic Surfactants such as ethoxylated fatty alcohols or alkylphenol ethoxylates, in amounts of 0.2 to 0.6 wt .-%, based on the resin solution, can be added.

In the manufacture of the coatings are initially for this purpose usual decorative papers with basis weights in the range of 60 to 150 g / m² impregnated with the impregnating resin solutions according to the invention, wherein the resin order about 90 to 150 wt .-%, based on the paper weight can be. In special cases can also be papers weighing 300 g / m² be impregnated with a resin order of 30 to 70 wt .-%. For big technical applications, the resin application takes place with the help of impregnating machinery. During impregnation, the advantageous Penetrationsver comes like the resin solutions, because the driving speed of the imprint also depends on the penetration behavior of the resin solutions.

The impregnation process is followed by a drying process, wherein the resinated paper in general to residual moisture content of 5 to 8 wt .-%, is set.

For those listed below in the examples and comparative examples aqueous resin solutions were each the penetration time after the determines the following method:

In a beaker, 100 ml of resin solution were conditioned (at 23 ° C, 50%). relative humidity). Then an air-conditioned paper disc (Base paper 80 g / m², ⌀40 mm) are placed on the solution. The time in which the Paper is completely wetted, is called the penetration time in sec. specified.

Examples 1 to 4 General rule

A mixture of 730 g of 40 wt% formaldehyde and 334 g of water tempered to 30 ° C, with 78 g of diethylene glycol and 38 g of ε-caprolactam ver sets, whereupon the pH of the mixture with 25gew.% Aqueous sodium hydroxide lye was adjusted to about 9.5. Subsequently, the addition of N- (2-hydroxyethyl) -trimethylammonium chloride and 790 g of melamine (each Amounts of ammonium compound used are listed in Table I).  

The reaction was then heated to 100 ° C, with the pH slowly dropped and stirred for about 60 min at pH 8.6-8.8. Once a sample the reaction mixture had a clouding temperature of 50 ° C, the Cooled reaction mixture to room temperature and the pH with 25gew.% Aqueous sodium hydroxide adjusted to 10-10.2.

Table I

Comparative Example A

A mixture of 730 g of 40 wt% formaldehyde and 334 g of water tempered to 30 ° C, with 78 g of diethylene glycol and 38 g of ε-caprolactam ver sets, whereupon the pH of the mixture with 25gew.% Aqueous sodium hydroxide lye was adjusted to about 9.5. Subsequently, the addition of 790 g melamine. Then, the reaction mixture was heated to 100 ° C, wherein the pH dropped slowly and stirred for about 60 min at pH 8.6-8.8. As soon as a sample of the reaction mixture to a turbidity temperature of 50 ° C. When the reaction mixture was cooled to room temperature and the pH adjusted to 10-10.2 with 25gew.% Aqueous sodium hydroxide solution.

Properties of the resin solution: see Table I Comparative Example B

A mixture of 812 g of 40% strength by weight aqueous formaldehyde and 358 g of water was heated to 30 ° C. With 25gew.% Aqueous sodium hydroxide solution was the pH of the mixture adjusted to about 9. This was followed by the addition of 821 g of melamine. It was then heated to 100 ° C and then up to condensed to a cloud point of 50 ° C. After reaching the turbidity point, the reaction mixture was cooled immediately. With 25% by weight aqueous sodium hydroxide solution was adjusted to a pH of about 10.

Viscosity of the resin solution (20 ° C) 45 mPa · s Solids content 57.6% by weight penetration time 15 s

Examples 5 to 11 General rule

A melamine-formaldehyde resin solution was analogous to Comparative Example B prepared and with varying amounts of N- (2-hydroxyethyl) trimethyl ammonium chloride added (the respective amounts are in Table II listings).

Table II

Example 12 to 13

The aqueous resin solution of Comparative Example B was 2.5 or 4.5% by weight, based on the solids content, of tetramethylammonium chloride added.

Table III

Comparative Example C

An impregnating liquor was prepared by treating an aqueous resin solution of Comparative Example A with water to a solids content of 55% by weight, and then with 0.4% by weight, based on the resin solution, of an 85% strength by weight aqueous solution a hardener (dimethyl ethanolammonium sulfite) and 0.3 wt .-% of a commercial alkyl phenol ethoxylate wetting agent.
Penetration time of the impregnation liquor: 6 s.

Example 14

An impregnating liquor according to Comparative Example C was admixed with 18% by weight, based on the solids content of the liquor, of N- (2-hydroxy) -trimethylammonium chloride.
Penetration time of the impregnating liquor: 2 s.

Comparative Example D

An aqueous resin solution was prepared analogously to Comparative Example A, however, when reaching the clouding temperature of 50 ° C 18 wt .-% based on the solids content of a 37 wt.% Aqueous solution, poly Diallyldimethylammoniumchlorid, based on the solids content added were. The clear resin solution was rapidly cooled to room temperature and then with 25gew.% Aqueous sodium hydroxide solution to a pH of 10 set.

Viscosity of the resin solution (20 ° C) 70 mPa · s Solids content 56% by weight penetration time 14 s

Comparative Example E

A mixture of 730 g of 40% strength by weight aqueous formaldehyde and 334 g of water was heated to 30 ° C. With 25% aqueous sodium hydroxide solution became pH adjusted to about 9.5. This was followed by the addition of 711 g Melamine and 79 g urea. While stirring, it was heated to 100 ° C, wherein the pH dropped slowly. Maintaining a pH of 8.5 to 9 by adding more NaOH, the reaction mixture was in the boiling heat stirred until a cloud point of 50 ° C was reached. By Cooling, the reaction was stopped and then the pH of the impregnating resin Solution set to about 10.

Viscosity of the resin solution (20 ° C) 40 mPa · s Solids content 58.4% by weight penetration time 14 s

Example 15

To an aqueous resin solution according to Comparative Example 13, 18.5 wt .-%, N- (2-hydroxyethyl) trimethylammonium chloride, based on the solids content was added.
Penetration time: 5 s.

Comparative Example F

A mixture of 1594 g of a 33% strength by weight aqueous formaldehyde solution, the pH of which was 8.5, and 702 g of urea became 45 for three hours heated to 50 ° C. Subsequently, the addition of 2170 g of a 52gew.% Aqueous urea-formaldehyde precondensate, which by Condensation of 1 mol of urea and 2 moles of formaldehyde in the form of a 33gew.% Aqueous solution was obtained at pH 4.5, while so long was condensed until a mixture of 1 g of resin solution and 1.5 g Water at 25 ° C turbidity occurred.

Then, the mixture of the two precondensates at 60 ° C for 1.5 hours heated and then cooled.

viscosity 25 mPa.s (20 ° C) Solids content 50% by weight penetration time 3 s

Example 16

The resin solution according to Comparative Example F was admixed with 20% by weight, based on the solids content, of N- (2-hydroxyethyl) trimethylammonium chloride.
Penetration time: 2 s.

Example 17

A mixture of 730 g of 40 wt% formaldehyde and 334 g of water tempered to 30 ° C, with 78 g of diethylene glycol and 38 g of ε-caprolactam ver sets, whereupon the pH of the mixture with 25gew.% Aqueous sodium hydroxide lye was adjusted to about 9.5. Subsequently, the addition of 16.5 wt .-%, based on the solids content of Tränkharzlösung, N- (2 Hydroxyethyl) trimethylammonium methylsulfate and 790 g of melamine. thereupon The reaction mixture was heated to 100 ° C, the pH was slow dropped and stirred for about 60 min at pH 8.6-8.8. Once a sample of the Reaction mixture had a cloud temperature of 50 ° C, the Cooled reaction mixture to room temperature and the pH with 25gew.% Aqueous sodium hydroxide adjusted to 10-10.2.

Viscosity of the resin solution 45 mPa · s (20 ° C) Solids content 59.5% by weight penetration time 5 s

Claims (4)

1. Aqueous resin solutions based on aminoplast resins, containing 1 to 35 wt .-%, based on the solids content of a low molecular weight quaternary ammonium compound of general formula I (R¹ _n R²₄ _-n N⁺) X⁻ (I) wherein n = 0, 1, 2, 3, 4 and R¹ is a C ₁ -C ₈ alkyl radical bearing a hydroxy group or an amido group, and wherein R ^{2 is} a C ₁ -C ₈ alkyl radical or a benzyl radical and X ^- for the Equivalent to an anion. 2. Aqueous resin solutions according to claim 1, containing quaternary ammonium compounds of the general formula I (R¹ _n R²₄ _-n N⁺) X⁻ (I) wherein n = 1, 2, 3, 4. 3. Aqueous resin solutions according to claim 1, the solids content of 40 to 70 wt .-% is. 4. Use of the aqueous resin solutions according to claim 1 as fast in Paper penetrating impregnating resins for the production of resin impregnated papers for the coating of wood-based materials.