DD301293A7 - METHOD FOR THE PRODUCTION OF BUTOXYLATED AMINO-CARCE PARTICLE SENSITIVES - Google Patents

Abstract

The invention relates to a process for the preparation of butoxylated Aminoharzprekondensaten which are applicable alone or in combination with other coating resins for finish films and plastic coatings. The object of the invention is the preparation of butoxylated amino resin condensates, which arise despite the use of different diamides with a narrow molecular weight distribution and without addition of catalysts with the usual solutions of short-oil alkyd resins or thermosetting acrylic polymers are indefinitely compatible and is very stable on storage as a one-component paint. According to the invention, specific process conditions are shown with which precondensates having a butoxy number of 350-370, an imine number of 500-550, a methylol number of 60-100 mg KOH / g resin and an average molecular weight of 450-700 and a polydispersity of 1.6 - 1.8 can be produced.

Description

Field of application of the invention

The invention relates to a process for the preparation of Aminoharzprekondensaten, which are used alone or in combination with other coating resins, primarily with special short-oil alkyd resins as a binder in thermally curable coating compositions for mainly finish films and plastic coatings.

Characteristic of the known state of the art Partially etherified melamine-formaldehyde condensates have long been used as binders, but predominantly as Binder components used in combination with other coating resins in thermally curable coating compositions. Essentially, the production of these condensates takes place in such a way that an aminotriazine with formaldehyde and a

Aliphatic alcohol is chemically reacted in the heat, the existing in the reaction mixture and formed

Water is removed by circulation distillation. Over time, different processes have become available for the production of

etherified aminotriazine-formaldehyde condensates formed by certain technological and material

Features have experienced their specific design. Usually condensates obtained in combination with alkyd or acrylate resins are obtained by this process Curing temperatures of 120 ° C give the required film hardness. In recent times, melamine resins or paints based on Aikyd-melamine resin are mainly for energetic reasons

have been developed which obtain sufficient after only a thermal curing at 80 to SO ⁰ C within 30 to 60 min paint properties (DD-PS 218764, DD-PS155621).

To achieve the necessary film hardnesses, however, additives of acidic catalysts or

multivalent crosslinkers required. These mulivalent cross-linking agents - in the simplest case urea- can both the

Molaminharz be added as well as the paint. In both cases, the additives have a positive effect on the reactivity,

but clearly negative on the storage stability. , ·

Furthermore, hard coatings are obtained by these additives, but in most cases they do not have the

required elasticity to impact such as impact and shock on the one hand, but before aging does not have the necessary flexibility

Manufacture rollable decorative films on the other hand to ensure. Another method for the production of stoving coatings on alkyd Melaminharzbaais for 80-9O ⁰ C is described in DE-AS1494 507

described. An essential aspect of this process is the presence of lower water-soluble alcohols, ketones or ethers during the condensation, in order to drain them in the desired direction. Another disadvantage is the

Concomitant use of methanol or benzene in the condensation, because they are contained in the resulting distillate and the Avoidance of environmental burdens a considerable effort for the distillate treatment with it. Furthermore, a partial substitution of melamine by urea or its derivatives was mentioned. The specified Reaction leads to mixed condensates in which significant proportions of melamine resins and urea resins

coexist. These products have a polydispersity that is still above the polydispersities of the classic

Melaminharze lie. Mixed condensates of this kind require at least 60min 80 ^c to achieve the necessary pendulum hardness. For quite some time, both the classic melamine resins and the mixed condensates have been through

the inevitable release of formaldehyde during and after the drying process, especially at the manufacturers of

Decorative films - get into the field of criticism. Despite many efforts to reduce the free formaldehyde (CH-PS 4911C7, NL PS 6805915) and the Methylolzahl, at

At the same time increasing the molar mass (DD 218764) can be developed with these resins no systems, which in their

Formaldehyde emission after the drying process by the action of e.g. Moisture or household chemicals under

0.1 ppm.

The water-dilutable melamine resins mentioned in the patent DE-OS 3705255 are characterized in combination with

self-crosslinking acrylic polymers by a low formaldehyde emission.

The disadvantage is their use in two-component paints. In addition to limited storage stability, hardening temperatures are still required in the case of the FlnLh-Follen coating of at least 14O ⁰ C despite the use of acid catalysts. In addition, the mentioned water-dilutable melamine resins are not suitable due to their low reactivity for stoving temperatures below 80 ⁰ C.

Object of the invention

The object of the invention is the preparation of butoxylloroben amino resin condensates, which are multivalent crosslinkers with a narrow molecular weight distribution (polydispersity below 1.8, hexamethoxymethylmelamine as reference substance in the molecular weight determination by gel permeation chromatography) without the addition of catalysts with the usual solutions of short-alkyd resin or thermosetting acrylic polymers indefinitely tolerable and as one-component coating with very good storage stability

1. at 130X the appropriate hardness, a formaldehyde emission below 0.1 ppm and the necessary flexibility for the production of rollable Dekorfojien and

2. at 70 ⁰ C well-adherent hard flexible coatings on plastic

result. Furthermore, these condensates should be produced in existing systems in time and cost-saving manner.

Explanation of the essence of the invention

"The object of the invention is a process for the preparation of partially etherified amino resin condensates from melamine,

Formaldehyde, n-butanol, diamides and / or polyhydric alcohols, with the. in these in existing, for the

Conventional melamine formaldehyde condensates used AnIn jun rationell can be produced, wherein a complete reaction of the diamides or polyhydric alcohols takes place without isolation of intermediates or end products. In this case, despite the use of different diamides a conventional mixed condensation should be avoided and thus the hardening ability and

Flexibility of the fabric made from it can be influenced. The workup of the condensate solution should be without additional Process steps carried out at atmospheric pressure. The solution of the inventive task consists in a new method, after etherified partially with n-butanol Amine resin precondensates with an e- · -n small molecular weight and high crosslinking reactivity using Melamine, bifunctional alcohol, unc. Diamides, aqueous formaldehyde and n-butanol when using special Cooling devices in the hitherto üulicl ι plant technology can be produced. The inventive method in detail is designed so that a mixture of melamine, formalin and the first part Butanol is adjusted with a NaOH to a pH of 3.0 . Subsequently, under normal pressure about 10-15% of Total amount of water distilled off together with n-butanol. After removal of the water, the corresponding diamides or their mixtures with ethane-1,2-diol and the remaining part Added butanol. By adding the appropriate amount of 1N HCl, the reaction mixture becomes neutral to slightly acidic

adjusted, wherein the heating is continued to distill off at atmospheric pressure, the water present in the reaction mixture with n-butanol. Thereafter, the condensate solution for 1 hr. Below its boiling temperature, but not higher than heated to 9O ⁰ C and then concentrated by distilling off the excess n-butanol with the remaining water until the condensate solution has a refractive index of n§ ° = 1.4700 ± 0.0030.

Surprisingly, it has been found that combinations of the precondensates prepared according to the invention with

hydroxyl-containing resins even at temperatures around 120 ° C. films with good flexibility, but especially in the case of

Foil coating have a formaldehyde emission of less than 0.1 ppm and show no tendency to curl. As far as the current state of knowledge with the classic melamine resins or melamine-urea resin mixtures

Accordingly, the orificer solution is based on the important new knowledge that by the chosen reaction and the targeted incorporation of a mixture of diamides or a diamide alone and its

Mixing with bifunctional alcohols structures can be achieved which guarantee a high degree of crosslinking,

At the same time, however, between the individual cross-linking points, the "mobility" necessary for the achievement of flexible rollable decorative foils is guaranteed.

The pre-condensate solutions adjusted to 50% are in proportion to a 60% solution of a short oil alkyd resin Alkyd resin to precondensate such as 7: 3 (solid on solid) combined. The films are applied to glass and decorative films and after

short vented burned at the appropriate stoving.

The results of the tests on the paint films with the precondensates prepared according to the invention are as in DD-PS 218764 un'd the DE-OS 3705255 reported test results in the following embodiments in tabular form

comparatively contrasted.

embodiments Exercise booklet 1 In a four-necked flask with a special distillation attachment for reflux distillation

"50g melamine

530g formaldehyde solution (30%) 400g n-butanol and 2.3ml 1N NaOH

submitted.

The mixture is distilled under reflux and simultaneous withdrawal of water. After removing 150ml of water

30 g urea 420 g butanol and 2.3 ml 1 N HCI

added.

The distillation is continued at a pH of 7.0 until complete decrease of visible water. Thereafter, the resin is heated at reflux for 1 h and then adjusted by distilling off n-butanol to a refractive index of n ° = 1.4700 ± 0.0030.

The precondensate has the following characteristics:

Methylolzahl (1,2) 62mgKOH / gHarz Butoxyzahl (1,2) 356 mg KOH / g resin Iminzahl (2) 528mgKOH / gHarz Molecular weight M _n (3) 680 polydispersity 1.74

Note on the methods:

(1) Plastics and Rubber 25 (1978) 1,48-59

(2) Plastic and Rubber 27 (1980) 9,528-532

(3) determined by gel chromatography using HMMM as a reference substance

Embodiment 2 Instead of 420g butanol are in the 2nd reaction phase

360 g of butanol and 60 g of 1,2-diol

used.

Key figures: Methylol number (1.2) 68mg KOH / g resin Butoxy number (1.2) 350mg KOH / g resin Iminzahi (2) 546mg KOH / g resin Molar mass M _n (3) 610 Polydispersity 1.60 Embodiment 3 Instead of 30g of urea will be in the 2nd phase

20 g of urea and 14 g of dicyandiamide

used.

Key figures: Methylol number (1.2) 73mg KOH / g resin Butoxy number (1.2) 364 mg KOH / g resin Imine Number (2) 505 mg KOH / g resin Molar mass M _n (3) 580 Polydispersity 1.78 Table 1 pendulum hardness of alkyd melamine resin and alkyd Aminoharzprekondensaten System combination

Paint according to Example Baking condition LacknachDD218764 1 2

30790 ⁰ C 80s 131 136

60770 ⁰ C 31s 56 54

Note: Determination according to TGL 29771 Table 2 Formaldehyde emission of alkyd melamine resin and alkyd amino resin precondensates

system -Combination 2 Paint according to example Lacquer to DO 218764 1 formaldehyde 0.5 emission after 0.2 10 days 1.6 0.5 4 weeks 1.2 0.2

Note: Determination according to WIHS 314

0.5 0.3

TABLE 3 Storage stability of Aikyd melamine resin and alkyd amino resin precondensates

System combination paint according to DD 218764 according to DE 3705255 Example according to FIG

Pot life

120 days

from 5 to 90 days

180 days

Table 4 Polydispersity and functionality per core

Aminoharznach 1 after example 3 DD218764 1.74 2 1.78 polydispersity 2.31 0.5 1.60 0.5 Methylol / core 0.3 2.0 0.6 2.0 Butoxy / core 1.7 3.0 2.0 3.0 Imine / core 2.2 0.4 3.1 0.26 Urea units / core 0 0.4

Claims (2)

1. A process for the preparation of Aminoharzprekondensaten from melamine, diamide, formaldehyde and butanol, characterized in that a mixture of 1 mole of melamine, 2.5 to 5MoI formaldehyde and at least 6.5 moles of n-butanol with alkali to a pH of> 7 up to max. 8 is adjusted and from 10 to 15 wt .-% of the total amount of water are distilled off together with n-butanol by heating, - Then the reaction mixture 0.2 to 0.5 mole diamide and further max. 6MoI n-butanol or at least 5MoI n-butanol and max. 1 mol of ethane-1,2-diol are added and adjusted with the alkali metal hydroxide equivalent equivalent amount of mineral acid to a pH of 6.8 to 7 and heated, with 30-50 wt .-% of the water contained in the reaction mixture together with n- Butanol is distilled off, - Then heated for a further hour at reflux to temperatures below the boiling temperature, but not higher than 9O ⁰ C and finally the formed precondensate solution is concentrated until a refractive index of njj ° = 1.470 ± 0.003 is reached. 2. The method according to claim 1, characterized in that is used as diamide urea or a mixture of urea with dicyandiamide in a molar ratio 2: 1.