DE2523166A1 - PROCESS FOR THE SHAPING AFTER-TREATMENT OF POLYURETHANE FOAM - Google Patents

Description

DEICHMANNHAÜS AT THE MAIN RAILWAY STATION

Cologne, May 15, 1975 Fu / he

Koepp Aktiengesellschaft, 6227 Oes trich / Rheingau

Process for the shaping caching treatment of polyurethane han s chaurns t o f f en «

The present invention relates to a method for the shaping aftertreatment of polyurethane foams under the action of pressure and heat.

It is known to heat polyurethane foams partially deform. At sufficiently high temperatures (over 300 ° C) the surface will partially decompose of the polyurethane sticky, which fact makes use of the so-called flame lamination process. At the same time Applying pressure and temperature (170 to 250 ° C) succeeds in making polyurethane foam particles together connect to. Here, too, there are superficial signs of decomposition, causing the individual foam particles is made possible.

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T-IJ -... im-yn M «41 _ ι. t “I.”. 8R8 2307 dona d ■ Tel «ir _Q mm: DomDatenl Cologne

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In the field of thermoplastics, to which
The polyurethane does not belong, it is known to wet the surface of pieces of Schauastoffstoff with dissolving substances, to compress and. to deform to form a composite body. This process is mainly used for polystyrene foams.

The thermal aftertreatment of polyurethane foams at temperature * which already leads to partial decomposition of polyurethane foam lead has a number of significant disadvantages. So it inevitably comes to an at least partial on the thermally treated surface Closure of the pores, as a result of which there is a local increase in the density and the formation of hardened ones Places is coming. These disadvantages are all the more serious as they affect the respective polyurethane foam product Give properties that are unreproducible and therefore unpredictable.

The aim of the present invention is a method for the shaping aftertreatment of polyurethane foams under the influence of heat, in which an end product is obtained that retains its original properties in all places essentially retained or predeterminable, and possibly continuously changing, a foam structure in principle, however, still has.

The essence of the method according to the invention is that the polyurethane foam to be treated with a organic solvent is wetted, the Donicity of which is greater than about 20, simultaneously and / or subsequently heated under deformation pressure and after evaporation of the. • solvent is cooled. The heating is carried out to such an extent that the desired deformation of the foam or the foam structure is fixed in the finished product without, however, the foam structure

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- 3 was destroyed as a whole.

To characterize the solvents used according to the invention which can act as electron pair donors, a characteristic number is defined which can be determined from a standard reaction. This standard reaction is the reaction of the corresponding solvent with antimony pentachloride in dilute solution in 1,2-dichloroethane, see V. Gutmann, "Coordination Chemistry in Non-Aqueous Solutions", Springer-Verlag, Vienna 1958. The donicity is the negative ^Δ Η the reaction of the solvent with antimony pentachloride: ie

Donicity = ~ ^ solvent χ SbCl ^.

If a polyurethane foam part in the invention: Sense with a solvent, the dizziness of which is greater. ; than approx. 20, wetted and heated, the poly swells; urethane foam on the wetted areas. Thereby j on the one hand, is its adhesiveness greatly improved, especially compared to other foam parts, and? on the other hand - if the wetting did not only take place superficially - a deformability of the treated poly j urethane foam part reaches «If you cool one of the j shaped polyurethane foam part after evaporation of the solvent, it retains its new j Form at. If several polyurethane molded parts, in particular only wetted on the surface, come into contact j heated together under lighter or stronger pressure, then form over the wetted surfaces solid bonds between the molded parts. The main advantage over this procedure According to the prior art, the treated polyurethane foam parts do not have any hardened areas and their homogeneity is not impaired in any way. Also the physical and chemical properties the treated areas of the polyurethane foam parts

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are not changed discontinuously compared to the original product, which results in significant advantages for many applications. Is of major importance for the process according to the invention that it is at temperatures can be carried out, which are deeper than conventional methods for deforming polyurethane foams.

Conveniently the heating is carried out of the wetted with the auxiliary liquid material to temperatures between about 40 and about 170 ⁰ C, for example between 80 and l4o ° C, preferably between about 100 and about l40 ° C. Below about kO ° C is carrying out the process according to the invention not possible, since there is no measurable softening of the treated polyurethane foam part. Above about 17O ⁰ C a destructive change starts with thermally sensitive polyurethane foams.

In order to achieve the best possible controllability of the process according to the invention, it has proven to be useful if the amount of solvent used for wetting is at least about 1 wt .- ^, preferably about 5 to 15 wt .- $ of the polyurethane to be treated or to be treated Schaurastoffteiles amounts. The reproducibility of the results is particularly good within these limits. If a larger amount of the solvent is used in relation to the treated polyurethane foam part, there is a risk, especially in the case of polyester-polyurethane foams, that if the required reaction times are not observed, clumps will form in places at the treated areas. With less than 3 tfo of the solvent, the heating interval can be long and there is a risk that the solvent, before it can develop its full puncture, already to the

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Most of it has evaporated, unless it is e.g. by a

Shape is retained in the material. ;

In a particularly important embodiment of the invention
the solvents with a Donicity greater than
20 not as such, but in freshening up with non-dissolvers
used for polyurethane foams. Non-solver in
For the purposes of the method according to the invention, those are aqueous
and / or organic liquid phases that are not in the
Are able to make deformability easier
of the polyurethane foam when heated. ; Organic nonsolvents are therefore in particular liquids with a donuticity of less than 20. Into consideration; come here, for example, alcohols, ethers, ketones, esters, [halogenated hydrocarbons and the like .. A for the invention 'most important non-solvent is water, as j the following will be described in detail. ;

The looseners used in the respective pail should!

expediently homogeneous with the i

Be miscible with solvents. Suitable pairs of substances can be determined through simple preliminary mixing tests. j

When selecting the appropriate non-solvent in each case, consider! According to the invention, preference is given to the type of dissolver used, so that in phase j, the expulsion of the auxiliary liquids, the volatilization; the solvent by the volatilization of the nonsolvent; is favored. Such a pail is for example! always present when solver and non-solvent readily volatile azeotropes form, if the non-solvent equal \ or severe evaporated as the solver or even if

the vapors of the nonsolvent are particularly capable of _;

ί are to take up solvent components and. from the foam:

to carry out fabric. The use of V / ater j has proven to be particularly suitable here in many cases

shown. !

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Through this use according to the invention of solvent / nonsolvent mixtures Not only does it facilitate precise dosing and distribution of the solvent in the foam, it does is made possible in particular by controlling the ratio of solver to nonsolver, in a certain way To influence the temperatures at which a permanent fixation of the polyurethane foam in the desired new form takes place. At the same time, the foam structure is reliably protected in this way against an undesirable excessive attack by the solvent. It is from the prior art, for example known that a for the invention Process particularly important solvent, namely the Dimethylsulfoxyd, is able to with simultaneous thermal treatment of polyurethane foam with degradation of the polyurethane and cellular foam structure to dissolve completely. Such a degenerative destruction of the polyurethane foam lies outside of the work area according to the invention. The invention wants through a suitable interaction of heat and solvent-based Liquid phase zvjar the deformability of the Ensure polyurethane foam, but at the same time basically preserve the foam structure. By Use of the above-mentioned solvent / non-solvent mixtures the wetting or soaking impregnation of the foam enables particularly reliable controllability the desired process result in a predictable manner.

According to the invention, it is preferred to use homogeneous solvent / non-solvent mixtures in which the volume ratio of solvent * to non-solvent is in the range from 3: 1 to 1:20. Volume ratios of 1: 1 or 1: 2 to 1:10 can be preferred.

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The use of solvent / nonsolvent mixtures containing water can in the process according to the invention au; House be particularly advantageous for the following reason: Will only one! wetting of the surface of one or more Polyurethanschaums.toff molded parts are aimed at deeper penetration of the solvent-containing mixture avoided in that most polyurethane foams are hydrophobic at least before the initial wetting with water. By mixing the organic Solvent with water contains the solvent / seamless mixture a largely hydrophilic character, so that a deeper penetration of the liquid into the polyurethane foam largely omitted. When heated, the dissolving effect on the polyurethane foam only occurs there in appearance where there is a solver. In this way, for example, the superficial gluing of parts made of plastic material is possible with each other without affecting the foam structure in the interior of the individual molded parts. Influence is exercised. It goes without saying, however, that foams can also be used with the aqueous auxiliary liquids soak continuously. Customary measures, such as kneading or squeezing off in a liquid, are suitable here kei tsbad.

The most important solvents for the purposes of the invention are

lower organic sulfoxides, especially dimethyl sulfoxide. Because such sulfoxides unlike most other organic solvents on human

Do not have a harmful effect on the organism and also with regard to j

do not disturb an odor nuisance, load at the same time!

with regard to the desired technical effect, however, be j

are particularly effective, they are the preferred solution i

means of the invention. The inventive method is j

but also possible if, for example, low j

Acid amides, e.g. methylformamide, ethylformamide, dimethyl- j

used for ', "-mid, Diethy If ormamid or Dime thy! acetamid

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will. These solvents enable the process to be carried out at relatively low temperatures relatively short time, which has a positive overall effect on the economic aspect.

The following solvents can be preferred for the inventive Procedure to be used:

Solvent Donicity (= DN)

Tetrahydrofuran 2o, 0

Methy! Formamide > 25

Ethyl formamide> 25
Dimethylformamide 26.6

Diet hyformamide> 27
Dimethylacetamide. 27.8 dimethyl sulfoxide 29.8

Tetramethylurea 29.9

N-methyl-2-pyrrolidone 27.3-

2-formylmorpholine> 27

Hexamethylphosphorus

acid triamide 38.8

The solvent preferably used according to the invention Dimethyl sulfoxide shows against all polyurethane foams essentially the same reactivity, i.e. its effect is evident both against polyether-polyurethane foams, Polyester-polyurethane foams as well as against special types, e.g. according to the Polyurethane foams produced using a cold foam process.

This applies essentially to all solvents, dimethyl sulfoxide, which can be used for the process according to the invention however, it occupies a special position because of the reaction conditions under which it is used can, (110 - 120 ° C) offer favorable conditions with regard to the process flow. On the one hand occurs relatively

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quickly, starting at ^ G C, the desired softening effect one, on the other hand it evaporates in the air flow after reaching the desired temperature (approx. 110 - 120 C) the dirnothyl sulfoxide largely so that the energy required for the evaporation of the solvent must be used is relatively small.

An important advantage of the method according to the invention is to see in it that the desired and desired Effect, if not the entire polyurethane foam part is to be treated, can be precisely localized to individual places without other parts of the same Polyurethane foam part thereby in the change be included.

The surface softening of polyurethane foam parts can be advantageous used according to the present process for the production of polyurethane foam composites will. For this purpose, it is useful if several polyurethane foam parts, e.g. foam curls, together wetted, heated, pressurized and cooled. In this way, a homogeneous composite body is obtained in which, depending on the respective compression, the Raumgei'jicht is optimally adjustable. This is an essential one Advantage over the conventional methods for the production of polyurethane foam composite bodies, which use an adhesive.

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The heating of the polyurethane foam partially or penetratingly wetted with the solvent or solvent / nonsolvent mixture can be carried out in a conventional manner, for example
be done by one-sided or two-sided
heated molds works. This is preferred
worked that during the heating process the
evaporating auxiliary liquid can escape.

A particularly uniform heating of the wetted polyurethane foam can be achieved if
For heating, hot air is pressed through the polyurethane foam part. This means that the response times in the
Inside and on the surface of the treated polyurethane foam parts of the same size and the end product has
a special evenness.

An important purpose of the method according to the invention; consists in the production of wholly or partially compressed polyurethane foam parts. So it is about ■ possible according to the fiction, contemporary method, a poly ■ urethane foam part that has a specific end shape; should assign, initially only as a blank from a block; cut, and then this blank to the j according to the invention Process "to subject, wherein the application of pressure j takes place in a mold. After cooling, the polyurethane, foam part can be demolded and now has the desired contours. · '

Polyurethane foam sheets can also be used in an analogous manner

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be copied. In this case it has been found to be beneficial proven when pressurization is continuous. The known ones are particularly suitable for this purpose Devices in which the foam web by means of a press belt moving along with a heated central drum and after a sufficient dwell time of her will be replaced again. Such a device for simultaneous continuous application of pressure and temperature of flat bodies according to the prior art can also without the level of wetting 'with a Solvent, i.e. solely under pressure and temperature for the compression of polyurethane foam webs be used. In this known case, however, higher temperatures (approx. 180 ° C.) are required, and they exist the negative effects already quoted above. Another disadvantage of this known method is that the compression of the foam webs takes place unevenly in terms of their thickness, that is to say the edge zones are very strongly compressed, the central zone only very little. In the present proceedings, however, the Compression evenly over the entire thickness, and the resulting foam web is therefore much more even Porosity, for example when using such webs for the production of artificial leather is of particular importance. In these cases, particularly good water vapor permeability is required, which can now be adjusted very well with the aid of the method according to the invention, while according to the old method a compromise between the thickness and the permissible porosity always had to be made here.

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In fact, the "method according to the invention" opens up a new and simplified way to produce artificial leather. Synthetic leather based on polyurethane pre-IB foams have been discussed over and over again, but the following significant difficulties have arisen so far on the other hand: The high compression temperatures for the foam in the range of 180 - 200 C make it economical Production in a continuous process difficult in practice * The heat conduction in the pressed foam is so bad that with final strengths over 1 ram an even Core heating is not achieved. This applies in particular to one-sided heating. The conventional one In any case, only certain softly adjusted Riyester foams are accessible to the pressing process. Polyether foams can only be used at temperatures that are approx. 20-30 ° C higher and even then only pressing irrigation.

In particular, it has not been possible to date to produce surfaces and adhesive films for such artificial leather on the basis of pressed Develop polyurethane foams that make manufacture of a finished product in one heating process, because coating and adhesive materials; that can be mastered in a temperature range of ISO - 200 C. would not be present in technical qualities.

The above-mentioned difficulties can be eliminated without great effort by the method according to the invention. If, for example, polyester or polyether-polyurethane foam is impregnated with an aqueous solution of dimethyl sulfoxide and squeezed off, so that a residual moisture of about 50 to 100 % of the foam weight, preferably about 60 % of the foam weight, remains, a material is obtained which behaves decisively more favorably in the subsequent pressing in discontinuous or continuous devices. By the invention

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Concomitant use of the solvent-containing liquid phase reduced. "I the required pressing temperature for example to 120 - 140 C. In this area but are stationary? and continuous press systems from gun manufacture known and generally available. It is still the thermal conductivity of the moistened Foam so decisively improved that a one-sided Heating is completely sufficient for a uniform sintering of the pressed foam and thus a fixation to achieve the foam structure pressed together? ;;;. This is obtained, for example, when the temperature is applied on one side from l40 C perfectly heated press vent pieces, if the polyurethane foam was previously soaked as described above.

Furthermore, in this embodiment it is the surf also possible to press ether foams in almost the same temperature range as ester foams, if this is soaked beforehand with aqueous dimethyl sulfoxide became. Finally, it is particularly important that in this working range of about 120 - 140 ° C prefabricated, common with artificial leather, Films, for example polyurethane and / or polyamide films let it be pressed without difficulty. The low amount of moisture in the foam does not interfere with this. the The porosity of the foam is sufficient even when it is compressed State off to allow the material to dry. In this way you can imitate the grain of the leather Apply cover foils to the press foam and also, for example, on the rear side by means of such adhesive foils Connect the textile webs to the press foam. It is therefore easily possible, for example, to use a layered Package consisting of: textile, polyurethane film, foam impregnated with aqueous dimethyl sulfoxide, polyurethane film, to be pressed into an artificial leather-like product in one operation. The whole thing is with them

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■ comparatively moderately increased IV mpe rat ure n of, for example 120 - 1ΛΟ ° C possible.

The invention is based on B _e r ispielen near explained.

In game 1

Zwed. Sheets made of polyether-polyurethane-VJeiohschauniatoff (Density o, o25) with the dimensions 250 χ 250 χ 50 mm are on a large square area with a Geraisch of 1 g DMSO (»pear tliylsulfoxid) and 5 g water

sprayed so that ~ 5, o g DMSO come together on the two surfaces. The sprayed sides of the two plates are then placed on top of one another and stored under slight pretensioning (compression to approx. «The total initial thickness) in a convection oven at 120 ° C. for about 60 minutes. The package is then cooled down and relaxed. Both panels are now seamlessly connected. where the connection point "can hardly be seen. The connection is boil-proof and has the same properties as the original foam.

Example 2

250 g polyurethane soft foam flakes with a grain size of 16 mm, mixed from commercially available polyether, bsw. Polyester-, Flexible polyurethane foam, four denier with a blend 25 g of DMSO and 62.5 S of water with brisk agitation evenly sprayed over. The result is a loose mass that is slightly moist to the touch. This comes in a box shape the dimensions 250 χ 250 χ 8θ mm compressed, both of which square sides are perforated. Then the filled form is blown from one side with hot air approx. 120 ° C, 50 mm WS blown. As soon as a

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If the thermometer shows a temperature of HO C on the left side of the flake, a lively evaporation of DMSO and water begins on the free, perforated side of the mold, which ends when the thermometer shows 60 - 9o C. Blowing hot air through is continued in order to remove DMSO-Reate, Mr.- the thermometer shows about 110-120 ° C. The heating is then switched off and cold air blown for a few minutes. The block is removed from the mold as soon as the thermometer shows 50 ° C. The result is a composite flake body with a density of 0.05 g / cm2 without hard adhesive layers between the flakes. .

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Examples ~ 5 to 11: Procedure as in Example 2:

Example Inserted Inserted solution flake center ! amount in (g)

Water temperature

proportion of .Hg ^ 3-

(ml) in air ( ^L C)

Water-

Solution

middle-

mixture

Enctem Knock by a door damsel inside (g / cm ^ ) ren the Flakes mixture (oc). loo oil 115

Flakes among each other

cn O CO OO

O CO CO CO

β 7

Io

11

5oo

looo 25o

500 500

2oo 500 500 5oo

40 gC% 2 ml) dimethylformamide

100 g ^ (Io6 ml) Dimethyl acetamide

2oo

700

loo g ("^ lojj ml) Tetramethylurea looo

75 g (^ 85 ml) Tetrahydrofura-n

5o s Γ55 ml) ethyl acetate (DN 17.1)

loo g for> i26 ml) Acetone (DN 17) '

150

2oo g (^ £ 45 ml) 3utanone- (2) (DN ° 2o)

5oo

1500

biethyl ether (DN 19.2) -

O)

75 g e * 93 ml) "ethanol (DN

0.05 o,

0.05

very gui

senr good

no

no

mäßi, ^

x: e me

Be is pie 1 12

2 plates of 2 ^ 0 χ χ 250 ο 30 mrn from room weight of polyether or polyester polyurethane foam, ο ^ g / cnr be sprayed as in Example 1 on one side with a DMSO Wasserpjerniseh. Then place in a mold as described in Example 2, first a plate with the sprayed side facing the center of the mold, then 25 ° g of sprayed flakes according to Example 2, then again the second plate with the sprayed side facing the flake. This package is compressed to a dimension of 25 25 loo mm and heated as described in Example 2. After cooling and demolding, a sandwich panel is obtained in the dimensions of the mold with an average density of 0.05 g / cm, which consists of a core of flake composite and the outer panels firmly connected to it.

Example 13 \

25o g of flexible polyurethane foam flakes with a grain size of 12 mm; mixed from any ether and Esterschaum ater be sprayed so that the surfaces are uniformly wetted \ with 80 g of V /. The result is a light, loose grip: moist mass. This is compressed in a box shape to the dimensions 250 χ 250 χ 80 mm, both of which are quadra- ^! table sides are perforated. Subsequently, the overall \ filled mold is blown on one side with hot air at about 120 ° C [5o mm V / S. A piece of foam 25o χ 25o x 50 mm is connected between the hot air blower and the mold, which is equal to a solution of 40 g of DMSO in 80 g of water . was moderately soaked. In the hot air flow is transmitted! the DMSO on the flakes embedded in the mold and is initially absorbed by the layer of water on it. The heating is then continued ₄

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As soon as a thermometer embedded in the interior of the flake mass shows a temperature of 40 C, it starts to open the free, perforated side of the mold is a lively evaporation of Dl'SO / water, which is finished when the thermometer 60-9 ° C shows. The bleeding of hot air 'will continued to remove DMSO residues until the thermometer shows about llo-12o C. Then the heating turned off and glassed with cold air for a few minutes. The block is removed from the mold as soon as the thermometer reaches 50 ° C shows. The result is a composite flake body with a Raunigevjicht 0.05 g / cm.

Example 14

A polyether-polyurethane foam prism (density 0.05 g / cm.) With the edge lengths 3o ° x 3oo χ 5oo mm is sprayed evenly over its surface with a mixture of 100 g dimethylformamide and 100 g water and placed in a mold with the masses 280 χ 2δθ χ 450 mm inserted. The mold is ^{heated to IJO 0} C for two hours. After cooling and demolding, a dimensionally stable foam body of dimension 280 χ 28ο χ k ^ o, the surface of which is compacted, is obtained.

Example 15

Proceed as in example 14.

Solvent used: dimethyl sulfoxide; Mass of the form: I50 χ 25ο χ 4 ^ o.

The demolded block has the dimensions of the mold and is dimensionally accurate.

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Hire Poly "'li> er-Polyurcthanochaurnplat1: .e (Jlaurnweight ^:

Ο, Ο- ¹ + e / cnr ^:) 1000 χ IGOO χ ? 5 mm is soaked in water in a VJanne in a 15 Gc ν; .- ί'ige η Log us of dimethyulfoxide in water. The foam sheet is then squeezed out until it contains 60% by weight of solution, based on the Schaunigewicht. Tn a Plattenprecsa din moistened foam plate at l-'iO 'is compacted ⁰ C with 5 kg / cm ¹ for two minutes. Do the cooling and demolding you get ^:

a compressed foam sheet with a thickness of 1.2 mm.

Proceed as in example l6 Thickness of the foam board: j30 mm : 25 g / ci; r

Solvent: Dime thy lace tamid (12% solution in V / water)

Press temperature: IJO ⁰ C Press pressure: 3 kg / cm "

Press time: 1 minute

Egg thickness of the foam sheet: 0., 8 mm

Example l8

An endless polyether-polyurethane flexible foam sheet (density 0.025 g / cnr, width 1.5 m, thickness 10 mm) is allowed to run continuously through a tub in which there is a 10% strength by weight solution of dimethylformamide located in V / ater. The web coming out of the tub is related to a $ 50 solution weight between squeeze rollers squeezed to foam weight. Together with a wide-meshed sheet of fabric (to prevent evaporation of the solvent to facilitate) the impregnated foam sheet is placed on the vulcanizing drum of an AUMA (with Suction). The temperature of the vulcanizing drum is! JO C, the pressure of the pressure

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des 4 kg / cm, the running speed 50 ra / hour (residence time about 6 minutes). Exiting the AUMA S cha urns toff web is long m over a 5 heated to 80 ° C Table run to the residual '' expel solvent. A foam web that is uniformly compressed over its total thickness of 0.4 mm is obtained.

Example 19 i

Proceed as in example 18.

Solvent used: dimethyl sulfoxide AUMA temperature: 125 ° C

Pressure of the'AUMA: 5 kg / cm ² Running speed: 60 m / hour

A uniformly compacted foam web is obtained

0.6 mm thick.

Example 20

Proceed as in example l8.

Solvent used: hexamethylphosphoric acid triamide.

AUMA temperature: 130 ° C

AUMA pressure: 3 kg / cm Running speed: 50 meters / hour

A uniformly compacted foam sheet η is obtained

0.5 mm thick.

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Claims (1)

lj method ζ ac for drive rid on post-treatment of polyurethane chaur:] :; t open u: i tc r- ':!' ivm? - e inv; ir kung. there, thou wilt go ke iinzo I need that: 3or polyurethane building material with an organizing
Slogan;. =: Λ & eel bo no tat uird, whose Donizit'it grower air,
(t ·: a 2o ii-t, gloiehssiti: and / odor subsequently on-forruin ^ ^sor;.? · :: ovv: -i ':: t and after driving off the solution submit
ab ^ eliüiilt * -. 'ird. 2. Vorfa.iro ^ nnch claim 1, thereby üe ': ennseic]: not that
dl /: rr '.'- r.:.un3 to' re ^ ipersturon zvjischen eti.'a ^} \ Q and
et · -; a ITv- 'j, before ^ u ^^ oise Aryan about 80 and about ■
l ^; f0 ° C takes place. ''). Procedure according to claims 1 or 2, characterized in that the serving lots. vjsnicßton-? etv; a 1 Gevi .- ']'>, vorzucövjeir.e about 5 to about '15 Gevi. ~ .J of the polyurethane .schaumstoffea is. i ¹ I. Ancestors according to claims 1 to ~ j>, thereby cökennselehnet,
that solvent / non-solvent mixtures are used, their
Voluniverk '-. Ltnis Löser to Hichtlöser vorzugsvjei.so im ■ Range ν on ~ 5'Λ to 1:20, in particular in the range of; 1: 1 to 1: io. 5. The method according to claims 1 to 4, characterized in that ' that water is used as a Hichtlösor. J 6. The method according to claims 1 to 5j thereby gekenzeichm- · ,,.
that as a solvent, low optionally substituted acid amides, for example methylformamide, ethylformamide, dimethyl _; formamide, diethylformami3, dimethylacetamide, in particular
but low organic sulfoxides are preferably used dimethyl sulfoxide ■■. j 509851/0968 Y. Process according to Claims 1 to 6, characterized in that that πΐ-'hrere polyurethane-Ochaurnstoffteile, z ^ B. Foam curls, wetted and heated when pressed together. 8. Verfuhren according to claim Y, characterized in that for heating hot air through the polyurethane foam part or the parts is or are pressed. 9. Procedure for continuing 'post-treatment of cross-linked Polyurethane foam sheets according to one of the claims 1-6, characterized in that the penetratingly soaked webs are optionally layered together with textile and / or plastic webs, are heated continuously with pre-pressing until the desired Compression of the foam web is fixed and optionally attached textile and / or plastic sheets are connected to the compressed polyurethane foam sheet. 50985 1/0968