Foam plastics and process for making them

Beginning of the patent period: March 15, 1967.

Foam materials are known to serve as insulating materials in building and heating technology and for damping mechanical vibrations.

A novel process has been found for the production of foams, which comprises polyesters, polyethers, polyols or polyamines having in each case more than one CH - acid radical bonded via oxygen or nitrogen in the manner of an aminoalkylation with an aldehyde and a Reaction product of a polyamine and CO₂ brings to implementation. In this case, 5-95% of the polyesters, polyols or polyamines or mixtures thereof carrying CH-acidic radicals may be replaced by copolymers carrying CH-acidic groups.

Reaction products of amines with carbon dioxide are described in the literature (see The 10 Chemical Structure of Some Diamines Carbamates JACS 73 1829 [1951]).

This process is distinguished from known processes for producing foams from polyesters and the like. characterized in that the serving as blowing agent CO is not generated by reaction of the very reactive isocyanates with water, but by cleavage from the above CO₂Conversion product arises.

The isocyanates used in polyurethane foam manufacture are very sensitive to water. Although accurately metered amounts of water may be added to the foam formulation, it is intended to have a particular and desirable chemical reaction, such as release of CO₂ and urea bridge formation. However, if water comes from the outside, for example when foaming in place on wet walls, with the foam approach in contact, so occur undesirable

Side reactions on. Furthermore, the removal of moisture caused by the isocyanate would make the setting of fresh mortar or concrete difficult and lead to damage to the components.

In contrast, the present process for the production of foams is insensitive to water, indeed, in the reaction itself becomes anhydrous. Foamed, unbound mortar or concrete will bond properly after this procedure.

An example of a compound having CH-acidic hydrogen-bearing radicals is the reaction product of adipic acid-glycol polyester with terminal OH groups and diketene. The compound corresponds to the formula

O = CO-R-OC = 0

CH

CH

Nr.258586

Herein R is the polyester radical of adipic acid and ethylene glycol having a molecular weight of about 400 to 4000.

At least the single stoichiometric amount of aldehyde is used in the present reaction. When using, for example, primary amines and / or CH-acidic compounds having two active hydrogen atoms, the reaction may continue and require a multiple of aldehyde.

The process products can therefore be varied widely in their properties. As the reaction of the aldehydes increases, so does the degree of crosslinking of the process product.

Suitable polyesters are compounds which are prepared, for example, from polybasic acids, for example adipic acid or phthalic acid, with polyhydric alcohols, for example ethylene glycol, butylene glycol, glycerol, hexane triol or trimethylolpropane, by known processes with a low acid number.

Suitable polyethers are compounds which are polymerized, for example, from ethylene oxide, propylene oxide or tetrahydrofuran, or are accessible as block copolymers by known processes.

Suitable polyols here are compounds such as ethylene glycol, propylene glycol, butanediol, glycerol, hexane triol and higher molecular weight OH-containing hydrocarbons.

As polyamines which contain nitrogen-containing hydrogen-carrying radicals via nitrogen, aliphatic and aromatic or heterocyclic compounds carrying primary or secondary amino groups can be used. For example, ethylenediamine, propylenediamine, butylenediamine, piperazine, phenylenediamine or benzidine are suitable.

Suitable amine C0₂Reaction products are, for example, those of di- or polyamines having primary and secondary amino groups which react with CO₂ to implement the corresponding carbamates, for example ethylenediamine, 1,3-propylenediamine, 1,2-propylenediamine, 1,4-butylenediamine, 1,3-butylenediamine, 1,6-hexamethylenediamine, piperazine, C-substituted piperazines and ethylene glycol bis • y-aminopropyl ether.

As aldehyde is suitable for the process preferably formaldehyde. However, it is also possible to achieve reactions with higher aldehydes, such as acetaldehyde or crotonaldehyde.

Here, CH-acidic hydrogen-containing radicals are those in which 1 or more H atoms on the C are activated by electron-withdrawing groups, for example at

<img file="AT258586B_D0001.tif" />

Preferably suitable are compounds which contain the acetoacetic acid radical

Nr.258586

CH₃ - C - CH - C, ./

\.

.0

0tragen. Among others, they have the advantage of easy accessibility by reacting compounds bearing acylatable groups, eg OH, NH, with diketene.

Above, CH-acid radicals can be located on compounds which contain at least two acylatable groups, for example on polyalcohols, such as butanediol, pentaerythritol and on linear or branched OH-terminated polyesters, furthermore polyethers, such as polyethylene glycol, polypropylene glycol, polytetrahydrofuran, furthermore polyamines, such as hexamethylenediamine, as well as polyethers or polyesters containing at least two primary or secondary amino groups or amino alcohols.

The above compounds are accessible in a conventional manner.

In order to obtain uniform foams with a certain pore density, it is advantageous to add small amounts of a surface-active substance. There are, for example, polysiloxanes, block copolymers of polysiloxanes with polyethylene oxides, alkoxylated phenols, alkoxylated alcohols, alkoxylated fatty acids, fatty alcohol sulfates, alkyl and aryl sulfonates and block condensation products of polyethylene oxide and polypropylene oxide.

The following procedure has proved to be advantageous.

The compound carrying CH - acid groups is mixed with the reaction product of polyamine and carbon dioxide and the resulting mixture is subsequently mixed with the aldehyde. Equivalent amounts of the three components are used. Shortly after. Mixing of the aldehyde occurs gas evolution, which corresponds exactly to the respective condensation rate, as can be seen from the following assumed reaction scheme:

2'CH +

<img file="AT258586B_D0002.tif" />

+ 2-C '&gt;

<img file="AT258586B_D0003.tif" />

H + h₂O

The rate at which the condensation reaction takes place is not critical within certain limits, since a slow condensation and thus a slow Viskoserwerden the approach runs a uniformly slow evolution of gas in parallel. In the case of rapid condensation, however, the evolution of gas proceeds accordingly rapidly, and in this case, too, a uniform foaming is ensured by the coupling of condensation and release of the blowing agent.

In general, no addition of further blowing agents is required. Likewise, it usually requires no heat from the outside, since the reaction proceeds sufficiently quickly at room temperature. Nevertheless, it may be advantageous to use low boiling solvents as propellants.

Low-boiling solvents which serve as blowing agents in the reaction according to the invention are preferably liquefied halogen-substituted alkanes, such as monofluorotrichloromethane, dibromodifluoromethane, 1,1,2-trichloro-1,2,2-trifluoroethane, dichloromethane, dichlorotetrafluoroethane, trifluorobromethane, methylene chloride It is also possible to use hydrocarbons, such as pentane or hexane, furthermore ethers, such as diethyl ether.

Suitable interpolymers for use in accordance with the invention are those which are compatible with the other components bearing CH-acid radicals and give homogeneous mixtures; In particular, those which are mutually soluble with the above-mentioned CH-acid-bearing compounds are mutually suitable. It is advantageous to use copolymers which are still liquid or highly viscous at room temperature.

Such copolymers are, for example, copolymers of various monomers with allyl esters or vinyl esters of β-ketocarboxylic acids, other unsaturated polymerizable dicarbonyl4

Nr.258586

Compounds or unsaturated polymerizable compounds bearing hydrogen at the carbon atom by electron-withdrawing groups such as the carbonyl and nitrile groups. Particular mention may be made here of the allylic and vinyl esters of acetoacetic acid or derivatives thereof and unsaturated malonic acid derivatives, in particular copolymers of vinyl acetate, vinyl isobutyrate or vinyl chloride on the one hand and acetoacetic acid allyl esters on the other hand.

In principle, unsaturated derivatives of other acids are also suitable as carriers of the active hydrogen in the telomerizate. Examples include cyanoacetic acid, p-nitrophenylacetic acid, o-nitrophenyl-.alpha.-hydroxyacetic acid, acetophenonemalonic acid, alkylmalonic acid, benzylacetic acid, pyruvic acid, .alpha.-alkylacetoacetic acid or carboxy-2,2-dicarboxyäthan. Suitable monomers which can form the abovementioned copolymers with the abovementioned allyl and vinyl esters are, for example, Vinyl esters, such as vinyl acetate, styrene, acrylic esters, such as methacrylate, methacrylic acid esters, such as methyl methacrylate, ethylene or vinyl chloride.

The amount of the compounds listed above in the respective mixtures depends on the nature of the desired foam. Thus, it is possible to replace 5 to 95% of the polyesters, polyethers, polyols or polyamines which are carriers of acidic hydrogen by the copolymers described above.

Example 1: A mixture of 18.4 parts by weight of branched polyether having the OH number 350 and the acid number &lt;1, ​​14.3 parts by weight of a branched polyester of adipic acid-phthalic acid-oleic acid-trimethylolpropane having the OH number 350 , Acid number &lt;1, ​​8.2 parts by weight of Ν, Ν, Ν ', N'-Tetrahydroxyäthyläthylendiamin, wherein the respective free OH groups are acetoacetyliert, is stirred with 13 parts by weight of the reaction product of piperazine and carbon dioxide. 1.05 parts of a mixture of oxalkylated fatty acid mixture and polysiloxane for pore control are stirred into the viscous pulp. Subsequently, 12 parts by weight of 50% strength methanolic formaldehyde solution are mixed into the high-speed stirrer, and then the creamy, homogeneous mixture is filled into the foaming vessel. The foaming is finished after a few minutes.

This gives a fine-pored foam, which can be removed from the mold after a short time and reaches its final strength after a few hours. Its density is 30 g / 1.

Example 2: 67.8 parts by weight of a weakly branched polyester of adipic acid-diethylene glycol and a triol having the OH number 60, acid number &lt;2, whose hydroxyl groups are acetoacetyliert, with 3.9 parts by weight piperazinecarbaminate and 0 , 8 parts by weight of polysiloxane stirred uniformly and mixed with 3.6 parts by weight of 50% formaldehyde in methanol rapidly to a creamy paste. The mixture is poured onto a plate and after a few minutes a moss-rubbery foam having a density of 200 g / 1.

Example 3: The following compounds whose OH groups are acetoacetylated are mixed well with one another: 36.8 parts by weight of a branched polyether having an OH number of 350, acid number &lt;1.28.6 parts by weight of a branched polyester Adipic acid-phthalic acid-oleic acid trimethylolpropane with the OH number 350, acid number &lt;1, ​​16.4 parts by weight of NNN'.N'-Tetrahydroxyäthyläthylendiamin.

20 parts by weight of finely ground titanium dioxide and 26 parts by weight of the reaction product of piperazine and carbon dioxide are added. Then 25 parts by weight of 50% strength methanolic solution of formaldehyde, which contains 2 parts by weight of one of the abovementioned surface-active, water-soluble substances for pore control, are stirred into the high-speed stirrer. The creamy, homogeneous product is poured into the foaming mold and, after drying the product which has been completely foamed after a few minutes, a rigid foam having a density of 75 g / l is obtained.

Example 4: 354 parts of the reaction product of a trimethylolpropane-propylene oxide polyether (OH number 561) with diketene, 420 parts of the reaction product of a trimethylolpropane propylene oxide polyether (OH number 404) with diketene and 150 parts of a copolymer of vinyl acetate, vinyl isobutyrate and allyl acetoacetate, wherein the proportion of acetoacetic acid allylester 24%, are intimately mixed. In the thus obtained clear homogeneous solution is stirred successively 12 parts of an oxyethylated nonylphenol surfactant, 220 parts of the reaction product of piperazine and carbon dioxide and finally 240 parts of 50% methanolic formaldehyde solution.

After stirring in the formaldehyde, the batch begins to foam immediately. This gives an open-pored, semi-rigid foam with a density of 35 g / 1.

Example 5: 200 parts of the reaction product of a propoxylated pentaerythritol (OH number 560) with diketene, 160 parts of the reaction product of a propoxylated trimethylolpropane (OH number 404) with diketene and 150 parts of a copolymer of vinyl acetate, vinyl isobutyrate

No. 258586 and acetoacetic acid allyl esters having an average molecular weight of 1680 are well mixed together; For this purpose, 4.5 parts of an alkoxylated fatty acid mixture and 4.5 parts of a water-soluble polysiloxane.

Thereafter, 120 parts of a reaction product of piperazine and carbon dioxide and finally 270 parts of a 50% methanolic formaldehyde solution are added to the reaction mixture with stirring at the high speed stirrer.

The batch is placed in a mold and foams to an open cell foam having a density of 30 g / l.

Example 6: 350 parts of the reaction product of a propoxylated pentaerythritol (OH number 560) with diketene, 354 parts of the reaction product of a propoxylated trimethylolpropane (OH number 561) with diketene, 200 parts of a copolymer of ethylene and acetoacetic acid allyl ester with the molecular weight 950, wherein the proportion of the latter is about 25%, 7 parts of an alkoxylated fatty acid mixture and 7 parts of a water-soluble polysiloxane are homogeneously mixed. In the mixture thus obtained, 250 parts of the reaction product of piperazine and carbon dioxide are added with stirring. 250 parts of a 50% strength methanolic formaldehyde solution are then added and, after homogenization, the reaction mixture is introduced into a frothing vessel.

This gives an open-pore, elastic soft foam with a density of 60 g / l.

Examples 7-12; The following parts by weight of a tetraacetessigester based on a propoxylated pentaerythritol (molecular weight about 800) and a copolymer of vinyl isobutyrate and Allylacetessigester of average molecular weight 1200 and an acetoacetic ester content of about 40% are mixed well with each other. For this purpose, 0.2 parts of an alkoxylated fatty acid mixture and 0.2 parts of a water-soluble polysiloxane are stirred. After further mixing of 11 parts of piperazinecarbamate, the reaction mixture is rapidly stirred homogeneously with 13 parts of 50% strength methanolic formaldehyde.

After pouring into a frothing vessel, foaming occurs immediately. This gives uniformly fine-pored foams of the specified density.

<td>example</td><td>Tetraacetoessigester</td><td>copolymer</td><td>g / i</td>

<td>7</td><td>19.8</td><td>35.5</td><td>35</td>

<td>8th</td><td>17.8</td><td>39.0</td><td>35</td>

<td>9</td><td>15.8</td><td>42.6</td><td>39</td>

<td>10</td><td>11.9</td><td>49.7</td><td>38</td>

<td>11</td><td>9.9</td><td>53.2</td><td>45</td>

<td>12</td><td>7.9</td><td>56.8</td><td>59</td>

Example 13; 50 parts of a tetraacetoacetate based on a propoxylated pentaerythritol (molecular weight about 500) and 50 parts of a copolymer of vinyl chloride and acetoacetate allylester with a proportion of the latter of 23% and the average molecular weight of 850 with 0.6 parts of a Biockmischpolymeren of polysiloxane mixed with polyethylene oxide as a surface-active substance. For this purpose, 17.8 parts Piperazincarbaminat are stirred in homogeneously, and after the mixing of 21 parts of 50% methanolic formaldehyde solution, the mixture is poured into a foaming mold.

The removable after a few minutes from the mold foam has a density of 35 g / 1 after drying.