DE2459753B1 - Amine-neutralised diol monoether hemi-phthalate in aminoplastics - as hardener with improved latency - Google Patents

Abstract

The cpd. (I) used as latent hardener for aminoplastics resins is a hemiester of phthalic acid with a monoalkyl or monoaryl ether (II) of a diol of formula H-(OCH2CHR) (OCH2CHR)x-OH (in which x = 0.20; R is H or Me), produced by reacting phthalic anhydride (III) with (II) in 1:2 molar ratio for 10-40 min. at 120-140 degrees C which is neutralised with an aliphatic, cycloaliphatic or heterocyclic amine (mixt) (IV). Pref. (IV) is morpholine. A greatly improved latency is obtd. by the use of specially selected esterification components. The flow characteristics and resistance to cracking are also improved.

Description

It has now been found that hardeners with significantly improved latency through a special selection of the esterification components when certain process conditions are adhered to can be obtained. The behavior of a hardener is under improved latency to understand, down to a critical temperature as possible The monoalkyl or monoaryl ethers of the dialcohols of the formula I are advantageously prepared by that one ethylene oxide or a mixture of ethylene oxide or propylene oxide to the corresponding attaches aliphatic or aromatic alcohol. In general, however, should not more than 40 mole percent ethylene oxide can be replaced by propylene oxide, otherwise the Reaction products become ointment-like to solid and hardly soluble in the system.

It is known that monoalkyl or monoaryl ethers of polyalkylene glycols to be used as a modifier for amino resins. Improve these connections in general the flowability and crack resistance of the amino resins. Included However, it can often be found that these compounds, if used in quantities over 8%, based on solid resin, can be used, similar to those containing hydroxyl groups Solvents (glycerine, methylglycol, higher boiling alcohols) during processing of aminoplast resins for surface coatings cause surface defects. This effect occurs in the case of the neutralized half-esters to be used according to the invention of phthalic acid with the monoalkyl or monoaryl ethers mentioned of the dialcohols of formula I is not caused. However, the effect of the improved flow behavior remains and the increased crack resistance.

The object of the present invention is intended to be based on the following Examples will be explained in more detail.

Example 1 148 g (1 mole) of phthalic anhydride and 296 g (2 moles) of mono-n-propyl diglycol are placed in a three-necked flask equipped with a stirrer, thermometer and reflux condenser and heated to 130 "C with thorough stirring.

The reaction mixture is stirred for 30 minutes at the temperature of 1300C before it is cooled down to 70 "C. Now the syrupy 444 g of water were added to the batch and the mixture was stirred until it was clear, homogeneous Solution has arisen. It is cooled to room temperature and neutralized with cooling with 174 g (1 mol) of a 50% strength aqueous morpholine solution.

The result is a 50% hardener solution with a pH of 7.2.

Example 2 148 g (1 mol) of phthalic anhydride and 276 g (2 mol) of des Ethylene glycol monophenyl ethers are reacted analogously to Example 1. The reaction mixture, which has been cooled to 70 ° C., is mixed with 424 g of water and afterwards Homogenization and cooling to room temperature with 150 g (1 mol) of a 50% strength N-methylethanolamine solution neutralized with cooling. It becomes a 50% hardener solution obtained with a pH of 7.0.

Example 3 148 g (1 mol) of phthalic anhydride and 364 g (2 mol) of des Monophenyl ethers of diethylene glycol are prepared analogously to Example 1 at 140 ° C. for 15 minutes long reacted. The syrupy reaction product cooled to 70 ° C 512 g of water are added and the mixture is stirred until a clear, homogeneous aqueous solution Solution has arisen. After further cooling to room temperature, it becomes acidic Reaction product with 174 g (1 mol) of a 50% strength aqueous morpholine solution neutralized by good cooling. The 50% hardener obtained has a pH of 7.2.

Example 4 148 grams (1 mole) of phthalic anhydride and 324 grams (2 moles) of mono-n-butyl diglycol are reacted analogously to Example 1 for 20 minutes at 135 "C. The temperature at 70" C cooled reaction mixture is mixed with 472 g of water and after homogenization and cooling to room temperature with 202 g (1 mol) of a 50% strength triethylamine solution neutralized with cooling. The 50% hardener solution obtained has a pH value of 7.2.

Example 5 148 g (1 mol) of phthalic anhydride and 356 g (2 mol) of monoethyl triglycol are reacted analogously to Example 1 at 1200 ° C. for 35 minutes. That on 70 "C cooled, syrupy reaction product is mixed with 504 g of water and Stirred until a clear, homogeneous, aqueous solution of the reaction product originated. It is further cooled to room temperature and the acidic reacting Reaction product with ice-cooling with 174 g (1 mol) of an aqueous 50% strength morpholine solution neutralized. The 50% strength hardener solution obtained has a pH of 7.1.

Example 6 148 g (1 mole) phthalic anhydride and 148 g (1 mole) mono-n-propyl diglycol are reacted and worked up analogously to Example 1. The approach will after cooling to 70 ° C., 296 g of water are added, all other details remain the same unchanged. A 50% hardener solution with a pH of 7.2 is obtained.

Example 7 148 g (1 mol) of phthalic anhydride and 138 g (1 mol) of des Ethylene glycol monophenyl ethers are reacted analogously to Example 2. The reaction product 286 g of water are added after cooling to 70 ° C., all other details remain unchanged. A 50% hardener solution with a pH of 7.0 is obtained.

Example 8 148 g (1 mole) phthalic anhydride and 148 g (1 mole) mono-n-propyl diglycol are converted into a 50% hardener solution as in Example 6. This hardener solution 296 g (1 mol) of a 50% mono-n-propyl-diglycol solution are now added, so that a hardener solution with the raw material composition analogous to Example 1 is obtained will.

Example 9 148 g (1 mol) of phthalic anhydride and 138 g (1 mol) of des Monophenyl ethers of ethylene glycol are as in Example 7 to a 50% hardener solution implemented.

276 g (1 mol) of a 50% strength aqueous solution are added to this hardener solution Phenylglycol solution, so that a hardener solution is analogous to the raw material composition Example 2 is obtained.

Application testing Proof of the latency of a hardener takes place by testing the hardening of an applied to a paper carrier Aminoplast resin under pressure at different temperatures. The hardening state the Aminoplast resin films pressed at different temperatures can be affected by acid resistance the aminoplast resin surface to be tested can be determined. The exam will be like carried out as follows: 0.2 N hydrochloric acid is allowed to act on the hardened, closed aminoplast resin surface. Then the chemical attack judged using a number scale from 1 to 6. No attack the dilute acid on the aminoplast resin surface means good curing and is rated 1 Complete detachment of the aminoplast resin from the paper carrier as an indication of poor curing, the number 6 corresponds to that for practice desired hardening state corresponds to a numerical value between 2 and 3. Through this number scale for the hardening state of the aminoplast resin films becomes the latency the hardeners according to the invention as polycondensation catalysts for amino resins described.

Another sample of the carrier webs soaked and coated as above is packed airtight in aluminum foil and stored at 30 ° C in a drying cabinet stored. The point in time is determined here by means of continuous test pressings the above conditions determined up to which the stored films flawless results when processing, d. H. closed, optically homogeneous surface coatings, result.

The production of the aminoplast resin-containing carrier webs as well as the Tempering of chipboard with these carrier sheets was carried out as follows: 200 g of an aqueous melamine resin solution prepared in a known manner (solids content = 55%; Molar ratio = melamine to formaldehyde = 1: 1.8; Water compatibility = 1: 1) become with 2 mmol des to testing known or to be used according to the invention latent hardener in the form of an aqueous 50% solution and 2 g of a release agent based on mineral oil (active ingredient content: wo0%) added and intensively mixed. A white, pigmented, absorbent high-grade cellulose paper with a basis weight of 80 g / m2 is soaked with this resin solution in a known manner and coated and then dried or precondensed that a carrier web with a basis weight of 200 g / m2 and a content of volatile components of about 6.5% results. The volatile content is the weight loss, the impregnated and coated paper carrier web in a temperature treatment suffers for 10 minutes at 1600C.

A part of these carrier webs is used for surface finishing a 16 mm thick chipboard used.

The pressing conditions are 3 minutes at 120, 130, 140 and 1600C on the heating plate of the press and 20 kp / cm2 pressing pressure. There will be asbestos press cushions used. The pressing takes place against high-gloss, chrome-plated brass sheets. After pressing, it is re-cooled. The surface coatings obtained are in terms of curing, crack resistance and visual appearance as well Unity judged. To determine the crack resistance, those with aminoplast resin coated chipboard is stored at 700 ° C. for 20 hours, with for assessment the crack resistance as well as the optical appearance and the cohesion of the surface coatings Tempered surfaces are used, the resin of which cures accordingly of the above definition have between 2 and 3.

The test results obtained are summarized in the following table.

Table of test results of the technical tests Melamine resins, hardened with known and inventive latent hardeners. Type of hardener (2 mol / 100 parts curing (indicated by storage fissure resistance optical Exterior-resistant melamine resin. The mmol- a numerical value from 1 to 6) ability / closeness The specification relates to the acidity when pressing melamine (good = x (good = x component of the hardener) resin films medium = x x medium = x x at 30 "C bad = x x x) bad = x x x) t20 ° C 1300C 140 "C 1600C (days) 1st ammonium salt of 3-4 2-3 1-2 1 8> <xx x x x / x x x p-toluenesulfonic acid (comparative hardener) 2nd triethanolamine salt of 5 4 3 2 15 x to x x x x / x monohydroxyethyl ester of oxalic acid (comparison hardener) 3. Half ester of phthalic acid 6 6 3 1 - 2 30 x x x / x with mono-n-propyldiglycol (cf. Example 1) 4th half-ester of phthalic acid 6 6 2-3 1 38 x x / x with the monophenyl ether d ylene glycol (see example 2) 5th half of phthalic acid 6 6 2-3 1-2 35 x x / x with the monophenyl ether of diethylene glycol (see Example 3) 6. Half-ester of phthalic acid 6 6 2 1 35 x x 1 x with mono-n-butyl diglycol (see example 4) continuation Hardener type (2 mmol / 100 parts of hardening (indicated by storage fissure resistance Optical exterior-resistant melamine resin. The mmol- a numerical value from 1 to 6) ability the hen / closeness information refers to the acidity during the pressing Melamine (good = x (good = x component of the hardener) resin films medium = x x medium = x x at 30 "C bad = x x x) bad = x x 120" C 1300C 1400C 160 "C (days) 7th half-ester of phthalic acid 6 6 2-3 1-2 30 x to x x x x / x with mono-ethyl-triglycol (see Example 5) 8. Half-ester of phthalic acid 5-6 4 2 1 15 xxx x x / x x with mono-n-propyl diglycol; Molar ratio 1: 1 (see Example 6) 9th half-ester of phthalic acid 5 4-5 2 1 20 x x x x / x x with the monophenyl ether of ethylene glycol; Molar ratio 1: 1 (see example 7) 10th half-ester of phthalic acid 6 4-5 2-3 1-2 20 x x to xxx x x x / x x with mono-n-propyl diglycol; 1 mol of the above glycol ether was added after the hardener synthesis (see Example 8) 11. Half-ester of phthalic acid 6 5 2-3 1 25 x x x x / x x with the monophenyl ether of ethylene glycol, 1 mole of the above glycol ether was added after the hardener synthesis (see. Example 9) The latent hardeners listed under 1 and 2 correspond to the current state of the art. The half-esters listed under 3 to 11 are in Form of their amine salts (see examples).

Especially the test results listed under 3 to 7 nisse of the table leave the essential advantages, such as significantly improved latency, good crack resistance as well as extremely positive surface-forming properties of those with the inventive Recognize hardeners cured melamine resin surfaces.

Claims (1)

to develop no or only very low hardening properties in order to then only at the processing temperature of the polycondensation resins by leaps and bounds Hardening properties to fully develop. If you enter the degree of curing as the ordinate in a coordinate system and the temperature as the abscissa, then with a non-latent hardener at given concentration and given time a straight line defined increase can be obtained. In other words, the hardening proceeds according to the temperature largely linear. In the case of a latent hardener, the slope of the straight line becomes initially be small, until the slope starts to jump from a certain temperature enlarged (onset of hardening effect). A hardener's latency is now reversed proportional to the slope of the first part of the curve, d. H. the smaller the slope of the first part of the curve, the greater the latency of the hardener, in the ideal case the latent hardener initially does not cause any hardening and the curve only at a certain temperature, if possible at the processing temperature of the polycondensation resins, rises steeply. It is clear to the person skilled in the art that the relationships described here idealized for both the normal and the latent hardener are. DL-PS 71 862 did not reveal that when phthalic anhydride was selected as an acid component, when using monoalkyl or monoaryl ethers of a dialcohol of the formula I and if the process conditions specified in the claim are adhered to a latent hardener with particularly effective latent properties can be obtained can. The improvement in the latency of the hardener is shown in the examples. In addition, the crack resistance of the resin surfaces obtained considerably improved The half esters of phthalic acid according to the invention come in form of their amine salts as latent hardeners, whereby primary, secondary and tertiary aliphatic amines, as well as cycloaliphatic and heterocyclic amines Amines can be used. The morpholine salts have proven to be particularly effective the half-ester proved. Particularly surprising and initially hardly understandable for the person skilled in the art is the fact that the best results are obtained when working according to the invention Phthalic anhydride with monoalkyl or monoaryl ethers of the dialcohols of the formula I in a molar ratio of 1: 2. As the acid number of the reaction product shows, is present in the reaction product phthalic acid in the form of its half ester. Unreacted phthalic anhydride can be found in the reaction products cannot be proven. Taking into account the molar approach, must be in the reaction product therefore at least 1 mole of the monoalkyl or monoaryl ethers of the dialcohols Formula I are free. If you choose a conversion ratio of 1 mol of phthalic anhydride and 1 mole of the monoalkyl or monoaryl ethers of the dialcohols of the formula I is obtained one half-ester of the same key figures, but it clearly deteriorated Effect on the process product to be used according to the invention surprisingly shows the effectiveness can also not be produced by using the above half-ester corresponding amounts of free monoalkyl or monoaryl ethers of the dialcohols. the formula I add. This finding, which can hardly be explained at first, is illustrated by the examples made clear. Claim: Use of a half ester of phthalic acid neutralized with an aliphatic, cycloaliphatic or heterocyclic amine or a mixture of these amines with a monoalkyl or monoaryl ether of a dialcohol of the formula where x is an integer from 0 to 20 and R is a hydrogen radical or a methyl group which has been obtained by reacting phthalic anhydride and the aforementioned monoalkyl or monoaryl ether in a molar ratio of 1: 2 by heating at 120 to 140 "C for 10 to 40 minutes , as a latent hardener for amino resins. The invention relates to the use of a half ester of phthalic acid neutralized with an aliphatic, cycloaliphatic or heterocyclic amine or a mixture of these amines with a monoalkyl or monoaryl ether of a dialcohol of the formula where x is an integer from 0 to 20 and R is a hydrogen radical or a methyl group which has been obtained by reacting phthalic anhydride and the aforementioned monoalkyl or monoaryl ether in a molar ratio of 1: 2 by heating at 120 to 140 "C for 10 to 40 minutes , as a latent hardener for amino resins. From DL-PS 71 862 is a method for improving the hardening properties of aminoplastic resins for the surface treatment of laminates, wood-based materials and molded parts known, wherein a mixture of 1000 parts by weight of an aminoplast resin solution and 2 to 40 parts by weight of a compound used, consisting of a partial Esters of di- or polybasic carboxylic acids, especially oxalic acid, with one and polyhydric aliphatic alcohols and their neutralization products with Amines, especially triethanolamine, exists. The use of these latent curing catalysts is said to result a considerable acceleration of the polycondensation processes during aminoplast resin curing can be achieved. Another advantage is said to be that the hardener is next to the hardening acceleration still exerts a plasticizing effect. On the process product this effect is supposed to be preferred by forming a closed, shiny one Show surface with low pressure crimps.