DD217795A1 - PROCESS FOR THE PRODUCTION OF POROESEN MASSES - Google Patents

Abstract

The aim and object of the invention is universally usable porous materials with chemical indifference and high temperature stability up to max. 473 K, which contain a large amount of readily available, cheap fillers, which are firmly integrated into the Traegerstoff. For the preparation of poroic masses of urea-formaldehyde precondensate with a durated time of 200 s, inorganic and / or organic fillers are mixed individually or in combination up to 60% by weight and by addition of hardener or catalyst in the presence of foaming agents, foam stabilizers and plasticizers cured. The fillers used are: gravel, chippings, talc, mica, kaolin, dolomite, metal powder, furnace slag, in particular phosphorus furnace slag, polystyrene flocs, urea-formaldehyde foam granules. The hardening is preferably carried out with concentrated phosphoric acid at a p H value of 6. The foaming agent used is an aqueous solution of a sulfonate-based foaming agent with a foaming agent concentration of 4%. Glycol and polyvinyl alcohol serve as plasticizer and as foam stabilizer.

Description

Process for the preparation of porous porous. masses

Field of application of the invention

The invention relates to a process for the preparation of porous masses, especially for the temporary storage of liquids «to be released in the slow evaporation process to the environment, as a carrier for catalysts, for filling reaction towers, as absorbent packaging material in the transport of easily breakable liquid containers , as a melioration full matsrial, as a container substrate. '. "-' ν '·., -'. ·. · - · '^; . · · ..:." Μ. · ·.

Characteristic of the known technical solutions

A process for the preparation of porous masses for the storage of liquids, in particular gases dissolved in liquids, is described in DD-PS 26,531 *

High porosity is achieved here with a cement mixture containing large amounts of diatomaceous earth. "Burning of foam concrete or other ceramic masses with aerated concrete, pumice, kieselguhr or infusarious earth leads according to DD-PS 2,832 to a material with high water absorption capacity, mixtures of chamotte , quartz, sodium chloride, magnesium stearate, sulfite waste liquor and water glass which are subsequently pressed into moldings, demonstrate the DD-PS 52 301 a high porosity "Granulated urea Formaldahyd-Schaurastoff,

the inorganic fillers up to 90 VpI .-% as gravel / grit, talc, mica u. a. contains / is described in the OP-PS 55-125 «132 as absorbent mass. In the cited patents for the production of porous masses it can be seen that the porous masses have very high bulk densities. For certain fields of application, porous masses with a high bulk density and thus increased closed-cell density of the system can only be used to a limited extent.

Object of the invention

The aim of the invention is to produce universally usable porous masses with chemical Indifferenz, especially against acids, alkalis, salt solutions, solvents, oxidizing and reducing agents and high temperature resistance to max β 473 K in a simple process.

With regard to the physical and morphological properties of the single grain are requirements, such as low bulk density of the ground substance, large void volume, combined micro and macroporosity, dimensional stability / high strength, in particular Reibungsfestigkeit and a good wettability · Furthermore, is in the selection of the suitability of the porous masses the Room stability of the bed or packing and the correctly selected absolute grain size with the decision.

Explanation of the essence of the invention

Based on the identified deficiencies of the known solutions, in particular the predominantly closed-cell nature of the known products, a high largely open-cell material structure is to be achieved with the method according to the invention. High open-air volume means high porosity and thus large void volume, resulting in a high water absorption

The object of the invention is to develop a process for the production of porous masses with the desired properties, which is based to a large extent on readily available cheap filling material which is to be firmly bound into the carrier. Fluids8aug®nda porous © Masses with a very high absorption capacity and a favorable pore space ratio over a longer period of time can be obtained by mixing urea «formaldehyde precondonate with a hardening time <200 see · with inorganic and / or organic filling material individually or in combination up to 60 G @ w »-% mixes and hardens.

As the inorganic material are z; B. Gravel * chippings, talc, mica, kaolin, dolomite, metal powder, Qfenschlacken and as organic material Polystyrolflocken, urea »formaldehyde foam granules suitable · The curing of the solutions thus obtained by means of hardener or · catalysts in the presence of a foam stabilizer, plasticizer and a Foaming agent in the mixture as an aqueous solution is achieved by intensive stirring or inflation by means of nitrogen, carbon dioxide or air. After hardening and drying, the comminution takes place to particle sizes <20 μm.

As a hardener or «catalyst is used phosphoric and / or acetic acid (l-2%) to adjust the pH to <6, as a foaming agent serve aromatic esters of sulfonic acids and as a plasticizer and stabilizer polyethylene or polypropylene glycol and polyvinyl alcohol ·. ..,. - .. .. .... '..- ...' , , .-.:. ··: .. ··; 'To further reduce the bulk densities, heating of the components resin precondensate, show solution and filling material to 293 to 363 K is possible.

embodiments example 1

1 to 150 parts by weight of urea-formaldehyde precondensate having a solid resin content of 30-35% by weight and a hardening time of <200 see are mixed with 40 to 60 parts by weight of phosphorus furnace slag with a grain size of <2.5 mm and a density of <3,000 m kg intensively stirred. With constant stirring, 10 to 20 parts by weight of foam solution with a hardener content of "4 % and a, Schäumümgehalt = 4 %, 1 to 5 parts by weight of polyvinyl alcohol and 1 to 5 parts by weight hardener or KataIysator added.

The curing of the system takes place at a pH <: 6 and a solidification time of 2 to 10 min. Porous mass produced according to this recipe shows the following characteristics:

, Density 1 450 to 1 480 m " ³ kg,

Bulkweight 400 to 500 m "" ³ kg

• Water absorption at 293 K below

Normal conditions 80 to 90 vol .-%, based on

a porosity of 50 % by volume

, Retention of water after 7 days of max. 90% by volume at 293 K under normal to 40% by volume, based on the conditions porosity of 50 % by volume ,%

The hardening time of the urea-formaldehyde precondensate was determined as follows: (coagulation method) 10 ml of the precondensate to be investigated (2Θ3 K) is placed in a glass tube sealed on one side and 1 ml of phosphoric acid with a concentration of 430 g H ₃ PO ₄ / l added , With constant slow swirling of the tube, the time from mixing to coagulation of the precondensate is stopped, (see.)

'·' .. - 5 - ^x '' · '''"

Example 2

From 100 to 150 parts by weight of urea-formaldehyde precondensate having a solids content of from 30 to 35% by weight and a hardening time of <200 seconds are mixed vigorously with 40 to 60 parts by weight of gravel with a grain size of <2.5 μm. · '''.'.''.-;; · ^J: "'' with constant stirring until a maximum of 0.5 parts by mass Harnstpff-Forraaldehyd foam granulate, 1 to 5 mass parts hexane triol and / or glycol, 1 to parts by weight of polyvinyl alcohol, 10 to 20 parts by mass of foam solution with a hardener content of" = 4% and a foam concentrate of = 4% and 5 to 10 parts by weight of hardener or catalyst added. The system cures at a pH <6 and a curing time of 2 to 10 minutes ^.

Porous mass produced according to this recipe shows the following characteristics:

, Density 1 350 to 1 450 m " ³ kg Bulk density 400 to 450 m ~ ³ kg

, Water absorption capacity at 293 K 85 to 92 vol .-%, referred to under normal conditions to a porosity of

55% by volume

, Water holding capacity

at 293 K below After 7 days of max. Normal conditions 92 vol.% To 35 vol.%, Based on a porosity of 55% by vol.

The high water absorption of 80 to 92% by volume, based on a porosity of 50 to 55% by volume, indicates a high degree of the open-cell nature of the system.

Claims (1)

Invention claim Point 1 . . '..'.//; : /. '"::'' ^: A process for the preparation of porous compounds based on urea-formaldehyde foam, characterized by "that urea-formaldehyde precondensate with a cure time <200 see wt with inorganic and / or organic fillers up to 60 -.% Total, individually or in combination mixed and cured by addition of hardener or catalyst in the presence of foaming agents, foam stabilizers and plasticizers at a pH <6 and temperatures between 293 and 363 K with intensive mixing optionally with inflation by means of propellant Point 2 A process for the preparation of porous compositions according to item 1, characterized in that as fillers gravel, chippings, talc, mica, kaolin, dolomite, metal powder, furnace slag, in particular phosphorus furnace slag, polystyrene flocks, urea-formaldehyde foam granules are used. point 3 A process for the preparation of porous masses according to item 1, characterized in that as foaming agent an aqueous solution of a foaming agent sulfonate-based with a foaming agent concentration of about = 4 % and a hardener or catalyst content of = 4 %, as plasticizer, preferably glycol, as foam stabilizer preferably polyvinyl alcohol and as a hardener or catalyst preferably phosphoric acid are used. Point 4 Process for the preparation of porous masses according to item 1, characterized in that, after hardening and drying, the material is broken to a particle size of 3 - Q mm. , '.-''. :. '·.