DE1620849C3 - Process for the production of foams from bituminous masses and / or tars, synthetic resins and optionally modifiers - Google Patents

Description

30th

The subject of patent 16 20 847 is a process for the production of foams from bituminous masses and / or tars, synthetic resins and optionally modifiers, in which mixtures of 50-80% by weight of bituminous masses and / or tars, 50-20% by weight % novolaks, and optionally modifiers and, optionally, tar bases of boiling range 160 to 190 ⁰ C, which, at a temperature of 150 to 210 ° C a viscosity of 50 to 500OcP simultaneously foamed at this temperature in the absence of a free acid with addition of hexamethylenetetramine and cured are, and the foams are optionally thermally aftertreated at 200 to 300 ° C for several hours.

The conditions required by patent 16 20 847 with regard to the viscosity and the absence of acids Mixtures for the foaming and hardening process can be set by a short-term thermal pretreatment of the mixture of bituminous mass and / or tar, novolak and optionally modifiers at 280 to 350 ° C or by adding tar bases from Boiling point 160 to 190 ° C for this mixture.

The invention relates to another advantageous embodiment of the method according to patent 16 20 847, which is characterized in that the conditions with regard to the viscosity and the absence of acid of the mixture for the foaming and hardening process by briefly pretreating the mixture with 0.1 be set to 0.3 parts by weight of hexamethylenetetramine per 100 parts by weight of the mixture at 150 to 160 ⁰ C. The pretreatment is preferably carried out for 15 to 30 minutes.

As in the main patent, natural asphalt, petroleum bitumens or, preferably, coal tars, lignite tars or wood tars or particularly preferably coal pitches, lignite tar pitches, wood pitches or aromatic-rich petroleum bitumens or mixtures of these bituminous masses in quantities of 50 to 80%, preferably 65 to 75%, are calculated as bituminous masses the mixture of bituminous mass and novolak, is used. According to the invention pitches are with softening points according to Krämer-Sarnow from 30 to 120 ⁰ C, preferably coal tar pitches having softening points of 60 to 85 ° C, is used.

The novolaks used are those based on phenol, cresols and xylenols in amounts of 20 to 50%, preferably 25 to 35%, calculated on the mixture of bituminous mass and novolak. According to the invention, novolaks with Krämer-Sarnow softening points of 70 to 110 ^° C. are used.

The foaming of the mixture, preferably by the gases released during the hardening process happens automatically, but also by adding known propellants, such as. B. Azo compounds or urea can be brought about, can also be added by introducing or blowing in finely divided Steam or gases are supported.

The mechanical properties of the foams produced can, if desired, by thermal Post-treatment at 200 to 300 ° C for several hours can be improved.

The mixtures to be foamed can be mixed with fillers such as talc, asbestos or carbon black modified with polyethylene, polyvinyl chloride or polystyrene.

The cell structure can be influenced by adding stabilizers, emulsifying agents and wetting agents will.

It has been shown that, with the procedure according to the invention, foams with good insulation properties, good mechanical resistance and extremely high temperature resistance up to 350 ° C and good chemical resistance can be obtained. The foams produced are not flammable.

In the case of pressureless expansion, according to the invention, foams with largely open pores are produced Working under pressure, i.e. in a closed vessel, foams with predominantly closed pores.

The following examples illustrate some preferred embodiments of the invention (the specified Parts are parts by weight):

example 1

300 parts of novolak (softening point 85 ° C) and 700 parts of coal tar pitch (softening point: 70 ⁰ C KS) are mixed with 2 parts of hexamethylenetetramine at 150 ⁰ C and stirred for 15 minutes at this temperature. The mixture is then ^{heated to 185 °} C. and the foaming of the mass is brought about by adding 50 parts of hexamethylenetetramine.

The fully cured foam has a density of 170 kg / m ³ . It has a heat resistance of 300 ^° C. and a compressive strength of 27 kg / cm ² .

Example 2

400 parts of novolak (softening point 92 ° C) and 600 parts of coal tar pitch (softening point 51 ° C KS) are mixed with 3 parts of hexamethylenetetramine at 160 ⁰ C and 15 minutes at this temperature

touched. The mixture is then heated to 185.degree. C. and the mass is foamed by adding 50 Parts of hexamethylenetetramine brought about.

The cured foam has a density of 150 kg / m ³ . It has a heat resistance of 300 ° C and a compressive strength of 36 kg / cm ² .

Example 3

350 parts of novolak (softening point 78 ° C) and 500 parts of coal tar pitch (softening point 60 ° C KS) and 150 parts of lignite tar pitch (softening point 55 ° C. KS) are mixed with 2.5 parts of hexamethylenetetramine mixed at 150 ° C and stirred for 15 minutes at this temperature. After that the mixture is on 190 ° C heated and the foaming of the mass through Addition of 50 parts of hexamethylenetetramine brought about.

The foam has a density of 175 kg / m ³ . It has a heat resistance of 300 ° C

ίο and a compressive strength of 29 kg / cm ² .

Claims (2)

Patent claims: 1. Process for the production of foams from bituminous masses and / or tars, synthetic resins and optionally modifiers, in which mixtures of 50-80% by weight bituminous Masses and / or tars, 50-20% by weight novolaks and optionally modifiers and optionally tar bases with a boiling range of 160 to 190 ° C, which are at a temperature of 150 up to 210 ° C a viscosity of 50 to 500OcP have, at this temperature in the absence of free acid with the addition of hexamethylenetetramine foamed and cured at the same time 'S and the foams optionally at 200 to 300 ° C for several hours are thermally aftertreated according to patent 16 20 847, thereby characterized in that the conditions with regard to the viscosity and the freedom from acids of the Mixture for the foaming and hardening process through a short pretreatment of the mixture with 0.1 to 0.3 parts by weight of hexamethylenetetramine per 100 parts by weight of the mixture can be set at 150 to 160 ° C. 2. The method according to claim 1, characterized in that the pretreatment 15 to 30 minutes is carried out for a long time.