DD220032A1 - METHOD FOR PRODUCING AMINO ILLUSTRATIVE MASSES - Google Patents

Abstract

The invention relates to the preparation nachschwindungsarmer amino resin molding compounds. The aim and the object of the invention is to produce amino resin molding compounds while maintaining a simple production technology which is customary for amino resins by adding a cardiac modifier, the processing of which is also possible without difficulty for complicated molded parts with reduced shrinkage. According to the invention, the resin condensation is carried out in the presence of N-substituted aminoalkane diphosphonic acids or salts thereof. The moldings produced from the amino resin molding compounds according to the invention can be used in particular in the electrical industry.

Description

XO -

is carried out, wherein R = H, alkyl-aryl

X = H ^ Me

Me = alkali, NRI

.: 0 ';-;-; ν- . - -;

Y * = C - R. # Preferably H

0 o

1 I ·. Y * CR γ C-NH-Y-

Q ORO

B XO Ν.: 'II 8 ^ OX

Y "= H, C" - R - '*: .. PC-PC

'"·' -Ι ..! -. Rl --___! ___ ^χο '.' ·. ''" ^Οχ '". '.' ,

can be. ^

2. The method according to item 1, characterized in that the N-substituted Aminoalkandiphosphönsäure or their, Salzjn amounts of 0.05 to 5 wt .-% based on the solid resin content of the molding composition is added. , _.

Field of application of the invention

The invention relates to the preparation of modified amino resin molding compositions, wherein the molded articles produced therefrom have a reduced Nachschwindung.

Characteristic of the known technical solutions ',

The shrinkage of Aminoplastformteilen, especially in continuous use under temperature load, is a known technical problem. For example, the shrinkage of molded parts made of 152 type molding compound is about 2%. For this reason, the use of pulp-filled melamine resin molding compounds for the production of parts with high standards of dimensional stability is not possible. Important areas of application, especially in the electrical industry, for which melamine resin molding compounds are predestined due to their good electrical insulation properties, tracking resistance, temperature resistance, solvent resistance and light fastness, were due to higher demands ah reliability, especially in the course of minimization of components lost. "

There has been no shortage of attempts in the past, by special Füllstoffkorhbinationen or special resin production conditions to produce Aminoharzformmassen with reduced Nachschwindung while maintaining the other favorable properties of the unmodified molding compositions. It is known to use reinforcing fillers, e.g. Glass staple fibers (Kunststoffe Jg.48 / i958 / 1 pp. 67-70). In this case, molding compositions with extremely low Nachschwindung '(<0.5%) are obtained, however, such molding compounds are not processable by injection molding or pressing machines and only deliver molded parts with a highly inhomogeneous surface, which are not suitable for use as visible parts.

Also known are low-melting aminoplast molding compositions obtained by the use of resins which have been condensed with a molar ratio of formaldeyde: aminoplast former = 1: (0.7 to 1.5) (DE-OS 2,824,473, DE.3.104.420). , However, these molding compositions are economically very unfavorable in their production. On the one hand, they entail technologically complicated processes, since the solubility limit of the aminoplast formers in the commercially available formaldehyde solutions has fallen short of, on the other hand, the raw material costs increase considerably due to the high proportion of aminoplastics.

Also known Aminoplastformmassen which are thermoplastic components such. As acrylonitrile-butadiene rubber, polyacrylate and polyacrylonitrile (US Patent 2,541,927, DE-PS 2,348,976) included, but the effect achieved in terms of reduced Nachschwindung the requirements of the electrical industry is not fair.

Object of the invention ^

The aim of the invention is to propose an economically favorable process for the production of low shrinkage aminoplast molding compositions.

-2-258 419

Explanation of the essence of the invention

The invention is based on the object, while maintaining a customary for amino resins simple production technology by adding a resin modifier aminoplast molding compounds whose processing is easily possible even with complicated moldings with reduced Nachschwindung. ;

According to the invention the object is achieved in that the condensation of the amino resins in the presence of at least one N-substituted Aminoalkandiphosphonsäu.re or Saiz the general Formej

0 I .P R I O- k ^s ox XO Y I \ where R = H, alkyl, aryl X = H, Me Me = alkali, NRI

Y ¹ S CR ₁ preferably H

I - H

Y = C-R, G - NH-Y "

O O R O

I! χο. I- I ^ οχ

Y "= H * C -R, / ^Ρ " ^C " ^Ρ \

can be. '-^:  : -Τ- - - ~ ^τ " ,_:       

The N-substituted aminoalkane diphosphonic acid or its salt is used in amounts of from 0.05 to 5% by weight, preferably 0.5 to 2% by weight, based on the resin content of the finished aminoplast molding composition.

The condensation takes place according to the generally customary production conditions for amino resins. It has been found that the effect according to the invention of the modifying agent which is also mixed with other phosphonic acids {e.g. S. Aminoethandiphosphonsäure) and phosphate can be used, regardless of the degree of condensation of the resin solution .'ist. '': '..' '"· ..;.

The further processing of the resin solution into aminoplast molding compositions is carried out by incorporating the customary organic and / or inorganic fillers, such as e.g. Cellulose, chalk, kaolin, barium sulfate optionally with the addition of known plasma assistants and dyes. Both the wet impregnation method and the conversion of the inventive resin solution into a powdered resin and its subsequent mixing with fillers and auxiliaries can be used to prepare a molding composition. According to both methods, molding compositions are obtained whose flow-curing characteristics do not differ from unmodified molding compositions of the same production technology. , '

The production of complicated moldings from the molding compositions according to the invention is easily possible. Depending on the modifier content, standard test specimens have residual values of 1%, with mechanical, electrical and thermal test values corresponding to those of the unmodified test specimen. , The invention will be explained in more detail with reference to embodiments, which are preceded by two comparative examples.

Example 1 ,

To produce a Vergieichsformmasse (Naßimprägnierverfahren) 682 parts by weight of melamine with 975 parts by weight of formaldehyde solution (30%) are heated to a boiling point at a pH of 8.5. The condensation is stopped after 15 minutes. The resin thus obtained is mixed with 560 parts by weight of cracked pulp and 4.5 parts by weight of Mg stearate in a Doppelmuldenkneter. The drying takes place over several hours at 80 ⁰ C to a residual moisture content of about 2%. The molding composition thus obtained is homogenized in a ball mill with the addition of 30 parts by weight of TiO ₂ .

Example 2 ..., · ".

4500 parts by weight of melamine are suspended in 6430 parts by weight of formaldehyde solution (30% strength). The pH is adjusted to 8.4 using NaOH. The condensation takes place at boiling temperature for 15 minutes. From the obtained resin solution, a solid resin is produced. 3566 parts by weight of the solid resin are homogenized with 2152 parts by weight of cellulose, 17.8 parts by weight of Mg stearate and 208 parts by weight of TiO ₂ in a ball mill. _v

Example 3

682 parts by weight of melamine are dissolved in 975 parts by weight of formaldehyde solution (30% pure). The pH adjustment takes place by means of NaOH to 8.0. To this solution are used as modifier 1.07 parts by weight of a mixture of N-substituted Aminöethandiphosphonsäuren consisting of 70% Ureidoethandiphosphonsäure and 30%

N-acetylaminoethanediphosphonic acid, given. After renewed adjustment of the pH to 8.0, the resin mixture is heated to boiling temperature and condensed after a short boil at a temperature of 80 ° C until a water dilutability of 1: 2 is reached, ie the addition of 2ml H ₂ O. to 1 ml of resin solution shows a clear turbidity. The preparation of the molding composition is carried out analogously to Example 1.

Example 4.

In 975 parts by weight of formaldehyde solution (30% strength) are dissolved 5.04 parts by weight of the mixture of N-substituted aminoalkane diphosphonic acids mentioned in Example 3, the pH is adjusted to 8.5 by means of NaOH. In this solution, 682 parts by weight of melamine are suspended. There is a condensation at boiling temperature, which is stopped after 15 minutes. The filler used is 300 parts by weight of pulp and 260 parts by weight of ground chalk (CaCO ₃ ). The work-up to form the composition is carried out as described in Example 1.

Example S

3.3 parts by weight of the modifier mentioned in Example 3 are dissolved in 858 parts by weight of formaldehyde solution (30% strength) and the pH is adjusted to 8.5 with 10% strength NaOH. Subsequently, 305 parts by weight of melamine and 76 parts by weight of urea are added and condensed with stirring for 15 minutes at boiling temperature. 359 parts by weight of pulp and 3 parts by weight of Mg stearate are impregnated with the resulting resin solution. The preparation of the molding composition is carried out according to Example 1.

Example 6

The procedure corresponds to Example 1, with the difference that 10.07 parts by weight of the sodium salt of the N-substituted aminoalkane diphosphonic acids mentioned in Examples 3 to 5 are added to the formaldehyde solution as modifier in the form of a 50% solution.

Example 7

In 9000 parts by weight of formaldehyde solution (30%), the solution of 93 parts by weight of a modifier containing 80 mol% Bis-ureidoethandiphosphonsäure and 10 mol% N-Acetylaminoethandiphosphonsäure. The pH is adjusted to 8.7 with NaOH. After addition of 6300 parts by weight of melamine is condensed at boiling temperature for 15 minutes. The termination of the condensation takes place at a water dilutability of 1: 6.0. From the obtained resin solution, a solid resin is produced. 3560 parts by weight of the solid resin are homogenized with 2152 parts by weight of cellulose, 17.8 parts by weight of Mg stearate and 208 parts by weight TiO ₂ in a ball mill.

Example 8,

682 parts by weight of melamine and 20.14 parts by weight of the modifying agent mentioned in Example 3 are dissolved in 975 parts by weight of formaldehyde solution (30% strength), the pH being adjusted to 8.5 by means of NaOH. The condensation and further workup of the resin is carried out according to Example 1. .., '.

From the molding compositions obtained according to Example 1-8 rod-shaped specimens are prepared, the Nachschwindung was determined according to TGL 14073 after a hot storage for 168 hours at 110 ± 2 ° C. The results are shown in Table 1 - _:

Table 1

Example. ',. Slowdown (%)

1 ' " .'" / . 1.85 '. ,

2 - 1.93 '', '. ,

3 0.78

4 ·; 0,93 5 ' ^: ' ν 'Ί' ⁵³

6., · · 1,11: '.. /

7. '. '1.01' ·. · '.'''

8: 0.74

Claims (1)

.Erfindungsansprüche: 1. A process for the preparation of aluminoplast molding compositions by condensation of melamine and / or urea with formaldehyde and homogenization of the resin with organic and / or inorganic fillers and optionally further additives and / or processing aids, characterized in that the resin condensation in the presence of at least one N- substituted aminoalkane diphosphonic acid or its salt of the general formula "" - "f ^ R