DE1167523B - Process for producing flame-retardant polyurethane foams - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school KL: C 08 g

Number:
File number:
Registration date:
Display day:

German class: 39 b -22/04

P 27912 IV c / 39 b
September 22, 1961
April 9, 1964

The production of cellular, foamed polyurethanes by reacting a polyhydroxyl compound with an organic, a variety of Isocyanate group-containing compound is known. When the components are brought together the hydroxyl groups sit with the isocyanate groups to form polyurethane bonds that cross-link the molecules, so that a solid plastic is formed.

In the manufacture of such plastics, a gas-generating agent is often used because of its action the mass, before it solidifies, takes on a cellular or foam-like shape that is maintained, when the mixture has reacted sufficiently. By means of suitable process techniques, such a cellular or foam-like structure of very low density and fine, even cell structure can be obtained. These products have many uses, e.g. B. for upholstery, for insulation purposes against heat and noise transmission or for other purposes.

A difficult problem with the foams produced heretofore is that they are relatively minor Flame resistance. Often a layer of foam will burn once it has been ignited, continue until it is completely burned.

The fire hazard of polyurethane foams is well known by adding certain substances that reduce the risk of fire. The best of the agents previously used for this purpose is finely divided powdery antimony trioxide. This improves the flame resistance of polyurethane foams. However, in order to obtain an appropriate To obtain flame resistance with this material are relatively large amounts (e.g. 10% of the more) required. The use of such large amounts is very disadvantageous, since the antimony trioxide to it tends to separate out during the manufacturing process and also greatly affects the compressive strength of the Foam impaired. Often it also leads to a friable foam with low abrasion resistance, which easily breaks down to a powder when rubbed. In addition, the burnt one glows Rest often further.

It is known to produce flame retardant foamed plastics using a mixture of ammonium halides adjusted to the neutral point, an easily fusible, weakly alkaline inorganic salt and a small proportion of a flame retardant compound which is customary as a plasticizer for polyester urethanes, as a flame retardant. The flame retardant method of making flame retardant
Polyurethane foams

Applicant:

Pittsburgh Plate Glass Company, Pittsburgh, Pa.

(V. St. A.)

Representative:

Dr. W. Beil, A. Hoeppener and Dr. H. J. Wolff,

Lawyers, Frankfurt / M., Antoniterstr. 36

Named as inventor:

Marco Wismer,

Louis Robert LeBras, Gibsonia, Pa.,

John Roscoe Peffer, Verona, Pa. (V. St. A.)

Claimed priority:

V. St. v. America September 22 , 1960

(57 642)

is achieved by the ammonium halide because it sublimes when exposed to heat and suffocates the flame. However, ammonium halides only exert a flame retardant effect as long as the ones they contain Foam materials do not come into contact with moisture. It also acts from the foam leached ammonium halide corrodes metal that comes into contact with it. In In another case, the foams have chloroalkyl phosphates or alkenyl esters of aryl phosphonic acids added. According to an older proposal, an optionally inert polyamide is used in Combination with phosphorus-containing or phosphorus-free polyols.

The present invention now provides a method for producing flame-retardant polyurethane foams from polyhydroxyl compounds containing at least 2 active hydrogen atoms, optionally polyisocyanates containing urethane groups, water or compounds containing free carboxyl groups or other blowing agents, catalysts and, if appropriate, reactive with NCO groups and / or optionally silicon-containing emulsifiers in the presence of nitrogen- and halogen-containing ones Phosphorus compounds, which is characterized in that as nitrogen and halogen-containing Phosphorus compounds a mixture of phosphorus

409 558/467

acid amides and haloalkyl esters of phosphoric acid is used.

These additives result in improved flame-retardant polyurethane foams without impairment their other desirable properties.

The mixture components to be used according to the invention are prepared according to known methods Processes such as the reaction of phosphorus-containing acids with suitable nitrogen-containing compounds, the bonded to the nitrogen atom contain active hydrogen atoms, such as. B. ammonia, Ammonium carbonate, ammonium carbamate, urea, urea-formaldehyde condensation products, melamine, Melamine - formaldehyde - condensation products, guanidine carbonate - formaldehyde - condensation products, Cyanamide, dicyandiamide, ammeline, cyanuric acid, dimethylolurea, guanidine, biguanidine, Biuret, ethyleneimine, trioxypyrin, diformylhydrazine, methylamine, dimethylamine, ethylamine, propylamine, Hydrazine, methylhydrazine or ethylhydrazine.

Some of the above compounds can be mixed directly with phosphorus oxychloride, phosphorus pentoxide, Phosphorus pentachloride or phosphorus trichloride are implemented. However, you can also use aldehydes, such as formaldehyde, have been reacted, whereupon the product obtained with the phosphorus-containing compound treated. Although the compounds so produced are usually solids insoluble in water represent, in powder form together with the phosphorus-containing plasticizer as a mixture component be added to the foamable mixture of polyhydroxyl compound and diisocyanate It is also possible to use liquid polyamides in essentially the same way works. An example of such a liquid phosphorus-containing polyamide is hexamethylphosphoramide formula

CH ₃

CH ₃

: n —P —N '

CH _S

CH _S of one or the other of the two components was possible. The excess of one component or of the unreacted components can have been removed at the end of the reaction by washing out or by other suitable measures. In some cases, in which the excess of a component is not so great that the material would be too acidic, its presence is harmless.

A useful manufacturing method is e.g. B. in ίο the USA. Patent Specification 2,544,706.

Regardless of the method by which the nitrogen- and phosphorus-containing Materials have been prepared or the reactants used in this process, It was found necessary that the products used according to the invention have a minimum amount of about Contain 10% nitrogen and 10% phosphorus so they go along with the phosphorus-containing plasticizer achieve the desired effect of increasing the flame resistance of the polyurethanes. Preferably the product should contain at least about 15% or more nitrogen and about 15% or more phosphorus, so that an optimal flame resistance is achieved. The amount of phosphora5 used Containing polyamide can range from about 2 to about 30 weight percent based on total Components of the foamable mass lie.

Suitable plasticizers according to the invention with solid, nitrogen- and phosphorus-containing compounds used to improve the flame resistance of polyurethanes and phosphorus and halogen atoms such as chlorine, bromine or fluorine can be obtained by reacting a phosphorus-containing Acid halide with an alkylene oxide have been obtained. They are therefore to be regarded as esters and usually have the following structure:

.0-R (X) _n , O = PO -Z

O-R (X) _7n

CH,

CH _n

Phosphorus-containing compounds which can react as acids with the active hydrogen atom in the nitrogen-containing compound or its aldehyde derivatives are, for. B. phosphoric acids such as phosphoric acid, phosphorous acid (H ₃ PO ₃ ), metaphosphoric acid, pyrophosphoric acid, hypophosphorous acid or polyphosphoric acids, phosphorus oxides such as phosphorus oxychloride, phosphorus halides such as PCl ₃ , PCl ₅ , PBr ₃ or PBr ₅ or mixed compounds such as

/ (OH) ₂

o: p:

in which R denotes hydrocarbon radicals having 2 to about 8 carbon atoms. X is a halogen atom such as chlorine, bromine or fluorine that replaces a hydrogen atom, and m is a number from 1 to 4 indicating the number of halogen atoms. Usually all R radicals contain halogen, although it is not excluded that one is free of halogen atoms or a lesser number of halogen atoms

contains than the others. The radical R can be ethyl, propyl, butyl, amyl, hexyl or another group which contains 1 to 8 carbon atoms in the chain, at least some of the hydrogen atoms being replaced by halogen atoms. Z can be the same group as - R (X) _7n .

It can also have the following structure:

"NH,

When combining the nitrogen-containing with the phosphorus-containing compound to produce a phosphorus-containing amide by known processes that improve the flame resistance of Polyurethane is suitable, the two compounds in equivalent amounts, based on the available nitrogen groups linked to reactive hydrogen atoms on the one hand or the on functional groups bonded to phosphorus, on the other hand, may have been used. An excess

G — Ο - Ρ — Ο

R (X) *

0-R (X) _n

G-O-P = O

OR (X) ₁₁ ,

in which G is an alkylene radical, optionally interrupted by ether bridges, such as ethylene, propylene,

5 6

Isopropylene groups or polyether radicals; η is an isocyanate that can be converted into polyurethanes. Number of z. B. 0 to 4; the symbols R, X and m have the following meanings for some organic diisocyanates. In those cases listed which are used for this purpose in which Z has the structure given above, tolylene diisocyanate, diphenylene diisocyanate, the esters can have been prepared in the manner that 5 triphenylene diisocyanate, chlorophenylene - 2,4 - diisocarbon acid is used first with a glycol, e.g. B. canate, ethylene diisocyanate, 1,4-tetramethylene diiso-ethylene glycol or propylene glycol, has reacted, cyanate, p-phenylene diisocyanate, hexamethylene diisocyanate so that an acidic diester is obtained, which is subsequently cyanate, 3,3'-dimethyl - 4,4 '- biphenylene diisocyanate , reacted with a halogenated monohydric alcohol 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, Polymeworden, whereby the desired halogen-containing io thylenpolyphenylisocyanat or diphenylmethane plasticizer is formed. 4,4'-diisocyanate.

Since the halogenated plasticizers are well known mixtures of two or more of these diiso-

To represent substances, it may be unnecessary, procedures to cyanate can also be used. Further to explain their production. So-called prepolymers come into consideration for suitable halogen ned plasticizers belongs z. B. the tris-dibromo- 15 by reacting an excess of one or propyl phosphate of the formula several of these diisocyanates with a polyhydroxyl

) connection can be obtained. If necessary, can

to form the prepolymers are heated to accelerate the reaction. ^w 20 The relative amounts of the organic diisocyanate

³ can cover a relatively wide range

or tris-chloroethyl phosphate of the formula can be varied. Usually this becomes organic

Diisocyanate used in an amount equal to the

l CHCH O) p = 0 hydroxyl groups is at least approximately equivalent.

² 2/25 If the latter compound is severely acidic, it is him

wishes when calculating the amount of diiso-

Of course, other similar cyanate components can also be used to treat the carboxyl groups - ester plasticizers of phosphoric acid, the halogen see. A range of half an equivalent and in which the hydrocarbon fractions contain up to about 2 equivalents of the organic diisocyanate Contain 1 to 8 carbon atoms in the chain and 30 per OH equivalent in the finished material comes in in which 1 to 3 hydrogen atoms are considered in the carbon.

Hydrogen proportions or even more due to chlorine, in the production of foamed polyurethanes

Bromine or fluorine are replaced, as mixture components it is usually necessary for the release of a be used. suitable gaseous substance in a liquid mixture

The halogenated plasticisers can make in an amount 35 before gelatinization fortgevon too far is about 5 based to 30 ° / _0> to the resin-forming steps. The usual method of releasing components of the foamable mixture, by means of gas, consists in the conversion of isocyanate. groups of the organic diisocyanate with carboxyl

To obtain a polyurethane foam, in groups or with water. This is how coal can be produced various common polyhydroxyl compounds are released in situ under suitable conditions which do not contain any phosphorus in the reaction mixture hold and do not represent phosphoric esters, but with and, when this has set, in the form of bubbles organic diisocyanates, such as toluene diisocyanate, or cells in the plastic are retained, react. Many of these are made of carbon, another and more recent method of manufacture

Hydrogen and oxygen, but can also contain other atoms made up of foam structures in polyurethanes. Examples of such are castor oil, in that one uses a gas generating agent, e.g. B. a mixture of polyethylene glycol and castor oil. The halogenated hydrocarbon, such as CCl ₃ F or the latter, is a glyceride of ricinoleic acid, in CCl ₂ F ₂ , in an appropriate amount, ie depending on which the fatty acid residue contains hydroxyl groups. Poly-grade, of the desired cell formation, blends with the polyesters of glycols, such as diethylene glycol or di-hydroxyl compound. If the diisocyanatopropylene glycol, are also useful, as is component for polymerization with the OH-Kompo-Polycarbonate. component is mixed, becomes the gas generating agent

Other polyester that evaporates with a phosphorus-containing heat of reaction, so that the Polyhydroxyl compound, a solid, nitrogen and desired cell structure is created. Another one containing phosphorus Connection and an organ 55 drive for the production of a cell structure in Polynische Diisocyanate can be converted to urethanes by making an emulsion of the flame-resistant polyurethane foams to liquid reactive components under suitable, are polyesters of acids, like the adipin- neten conditions mechanically moved to air or acid or phthalic anhydride, and more - to introduce another gas. The foaming Valuable alcohols, such as diethylene glycol, Pro-60 can be increased by adding the mixture pylene glycol, trimethylol ethane or mixtures thereof. during or after mechanical movement Another class of compound is made by first overpressure and then underpressure Polyether represents, which by reacting one exposes one or by only one under pressure multiple hydroxyl group-containing compound.

like sucrose or sorbitol, with an alkylene oxide 65. H. the off

have been received. Carbon, oxygen and hydrogen existing

The aforementioned polyhydroxy compounds OH compound, the organic diisocyanate, the

can in suitable amounts with organic di-halogenated phosphorus-containing plasticizers and the

insoluble phosphorus-nitrogen compound, the foamable mass may contain certain auxiliary substances, z. B. Curing Catalysts. However, the addition of such substances is not mandatory. Curing catalysts are z. B. tertiary amines or organic metal compounds, such as the following:

Tetramethylguanidine,
Tetramethyl-1,3-butanediamine (TMBDA),

Triethylenediamine (DABCO) = CH ₂

CH ₂

CH ₂ CH ₂

"N '

CH ₂

CH,

Dimethylethanolamine (DMEA), tin ester, e.g. B. stannooleate, stannooctoate, dibutyltin dilaurate,

or other catalysts such as those used in the production of polyurethane foams. the The above information is for explanation purposes only.

The customary catalysts for the production of polyurethanes can be used in the process according to the invention Manufacture of the flame-resistant polyurethane foam peat can be used.

The amount of catalyst can be in the range from about 0.1 to about 5 percent by weight, based on the reactive components of the foamable composition.
Another tool to use in making

ίο flame retardant low density foams Valuable are surfactants that help maintain the cell structure of the foam to serve. Such agents are described in "Synthetic Detergents and Emulsifiers" by John W. McCutcheon; these publications appeared in July, August, September and October 1955 in "Soap and Chemical Specialties" and were reprinted together. On the they were brought up to date in 1958. Most of the emulsifiers used are more non-ionic Art.

Another class of surfactants has the following formula:

, (OC ₃ H ₈ MOC ₂ H ₄ ^ OH
ζ NCH _t CH, N (
HO (C ₂ H ₄ OMC ₃ H ₆ O): / (OC ₃ H ₆ MOC ₂ H ₄ ^ OH

Other surfactants that prove to be very

effective in maintaining cell structure - in foaming and hardening of flame-resistant Polyurethanes have been shown to be silicone derivatives such. B. the formula

0 (R ₂ SiO) ₉ (C _n H _2n O) ₂ R ″, namely from 21.5 parts by weight of it with 78.5 parts by weight of tolylene diisocyanate (80:20 mixture). The prepolymer was mixed with a blowing agent, namely CCl ₃ F mixed, the temperature being kept below the boiling point of CCl ₃ F. In the mixture, the components were present in the following ratio:

Prepolymer 100 parts by weight

_{CCl 3} F 46 parts by weight

in the R ', R and R "monovalent hydrocarbon radicals In the second component were the remaining

are; p, q and r are integers, namely at least constituents of the foamable material incorporated, 1 or higher up to about 20; η is about 2, 3, or 4; ζ is ie the same polyhydroxyl compound as it is for an integer, namely at least 5 or higher, the prepolymer was used, the catalyst, e.g. B. up to about 25. Other surface-active agents, 45 the surface-active agent and the flame-especially the liquid or soluble non-ionic resistance-increasing agents. The two components were mixed with stirring, whereupon foaming and solidification occurred. This usually takes about 100 to 400 seconds

Mixture of polyhydroxyl compound and organic 50 claim. The mass was then used in a schematic disocyanate. In relative oven at a temperature of about 65 ° C for 1 hour moderately dense foams, z. B. those around
The .80 to 0.95 g / cm ³ and more can weigh
Surfactants omitted entirely
will. 55

The following examples explain the improvement in the flame resistance of foamed polyurethanes by adding a phosphorus-containing polyamide

The same members of this family are also useful. The surfactants can be used in amounts of about 0.1 to about 3 percent by weight, based on the

and an inert halogenated phosphate or phosphonate which is a plasticizer.

Example I. In this example a prepolymer was cured. Of course, the temperatures and curing times can be varied in a known manner.

The effectiveness of the phosphorpolyamide components used according to the invention was tested in a series of tests and the inert plasticizer is determined. In control experiments, the plasticizer was used alone used as a flame resistance-increasing agent, while in other control experiments one solid, powdery, phosphorus-containing polyamide as the only agent that increases the flame resistance had been used. In other experiments, the two, flame resistance, were used according to the invention

a polyhydroxyl compound and toluene diiso- 65 increasing agents are used. In any case, there was

cyanate made from a polyether- the inert phosphorus- and chlorine-containing soft-

Glycol, which is made by converting 1 mole of sucrose, from trisdichloropropyl phosphate. The co-

11 moles of propylene oxide and 4 moles of ethylene oxide produced the phosphorus-containing polyamides

The moles of the components are given in the table below under the designation “polyamide”. The different compositions used

10

and those relating to the flame tests according to ASTM-t The results obtained from method D 1692-59T are compiled according to + the following:

Ilen 1 Vorpoiymeres CCl ₃ F Poly-
ether Polyhydroxyl compound polyamide
Molar ratio G *) catalyst density Flame test the end length Test-
No. 2, G Soft-
m ach he the none Seconds inch Con 2 G 42 G XX1 Cl v * XX VsX Components G g / cm ³ (ASTM D 1692-59 T) 2.8 inch / min. 3 100 86.0 G } ¹⁵ Tetramethyl
ethylenediamine 0.028 2.54 cm 4th 30th 25th }> 0.7 Seconds 5.2 inch / min. 5 100 30th 85.0 4.5 urea
1 P ₂ O ₅ } ' Tetramethyl
butylenediamine
1.0 0.032 burned 9.6 inch / min. 100 30th 85.0 none < 1 POCl ₃
5 NH ₃ } l5 Tetramethyl
butylenediamine
1.0 0.029 7.7 inch / min. 6th 100 30th 85.0 none < 4.5 urea
1 P ₂ O ₅ Tetramethyl
butylenediamine
1.0 0.033 burned 5.2 inch / min. 100 85.0 none ·! 1 POCl ₃
5 NH ₃ } ⁵ Tetramethyl
butylenediamine 0.030 burned 7th 46 none 1.0 burned 32 100 83.0 1 POCl ₃
5NH ₃ } io Tetramethyl
ethylenediamine 0.026 burned 8th 46 M. 0.78 23 5/8 100 83.0 1 POCl ₃
5 NH ₃ [15 Tetramethyl
ethylenediamine 0.024 28 9 46 ³⁵ { 0.78 27 13/16. 100 83.0 1 POCl ₃
5 NH ₃ I 4 Tetramethyl
ethylenediamine 0.023 - · 10 42 20 y 0.78 30th 100 86.0 1 POCl ₃
5 NH ₃ ! ^8th Tetramethyl
ethylenediamine 0.026 - 42 20 y 0.7 36 - 100 86.0 1 POCl ₃
5 NH ₃ Tetramethyl
ethylenediamine 0.027 21 20 y 0.7 17th

*) In addition to the active ingredients, this phase received a small amount (1 g) of a surface-active agent containing Si.

The plasticizer in the table is tris dichloropropyl phosphate. It is clear that this plasticizer can be replaced by other chlorinated phosphate plasticizers which, as described above, are inert. Likewise, the phosphorus-containing polyamide can be replaced by other phosphorus-containing polyamides will. The sucrose polyether can be replaced by other polyhydroxy compounds. as well The surface-active Si-containing agent having the properties described can be replaced by others which are suitable for emulsification and foaming by physical action to promote the mixture. Instead of the catalysts used, others of the aforementioned can also be used Catalysts are used.

The test material used in the control experiment, which is only one of the substances that increase flame resistance Contained substances was completely burned. By adequately loading the foam with a of the agents influencing the flame resistance, it might be possible to achieve a certain degree of flame resistance to reach. However, this would not be economical and could reduce the compressive strength, the cell structure, the Impair the resistance to moisture and other properties.

Example II

The sucrose polyether of Example I is replaced by a polyether obtained by reacting 1 mole of sorbitol with about 6 to 10 moles of propylene or ethylene oxide. Part of the polyether obtained is mixed with an excess of isomeric toluene diisocyanate (80:20 or 65:35 mixture). To the prepolymer, a polyhydroxyl compound is added, the same or different from that used in the prepolymer. So much is used that it will react with the available isocyanate groups in the prepolymer. The prepolymer can contain about 30 to 70% of the total polyhydroxyl compound. The gas generating agent, e.g. B. CCl ₃ F, is preferably added to the prepolymer in an amount of about 10 to 400 percent by weight, based on the polyhydroxyl compound in the prepolymer.
, The phosphorus- and halogen-containing plasticizer is used in an amount of about 5 to about 30%

409 558/467

based on the total weight of the reactive constituents of the foamable mass, used. The phosphorus-containing polyamide is used in an amount of about 2 to 30 parts by weight on an equal basis Base added.

The surfactants and catalysts used in Example I can be used will. Their amounts, based on the OH component, are essentially the same as in the above Example. The prepolymer and the OH component are mixed, foamed and hardened as in example I.

Example III

The prepolymer of Example I is made up of a prepolymer of about 70 to 80 parts of a mixture of tolylene diisocyanate isomers (80:20) and about 20 to 30 parts of polyester of the following composition replaces: so

Phthalic anhydride 0.5 mol

Adipic acid 2.0 moles

Trimethylol ethane 3.1 moles

Ethylene glycol 1.1 moles

35

The blowing agent (CCl ₃ F) is added to the prepolymer and further polyesters, the flame resistance-increasing agents, catalysts and surface-active agents are added to this mixture in order to obtain a foamable composition as in Example I. The amounts used can be the same or similar to those in Example I.

The mass is foamed and hardened as in the previous examples.

Claims (3)

35 claims: 1. Process for the production of flame-retardant polyurethane foams from polyhydroxyl compounds containing at least 2 active hydrogen atoms, optionally containing urethane groups, polyisocyanates, water or free carboxyl groups containing compounds or other blowing agents, catalysts and optionally with NCO groups reactive and / or optionally silicon-containing emulsifiers in Presence of nitrogen- and halogen-containing phosphorus compounds, characterized in that that as nitrogen and halogen-containing phosphorus compounds a mixture of Phosphoric acid amides and haloalkyl esters of phosphoric acid is used. 2. The method according to claim 1, characterized in that a phosphoric acid amide-phosphoric acid haloalkyl ester mixture is used, the amide component is the polyamide of a phosphoric acid contains, in whose N - P group Nitrogen as amide nitrogen in an amount of at least 10 percent by weight and also pentavalent Phosphorus occur in an amount of at least 10 percent by weight. 3. The method according to claim 1 or 2, characterized in that a phosphoric acid amide-phosphoric acid haloalkyl ester mixture is used, which contains haloalkyl esters of phosphoric acid as the haloalkyl ester component the general formula OR (X) _n ,
O = P ~ O-Z
OR (X) _n , in which R (X) is a haloalkyl radical with at least 2 carbon atoms, Z is the group R (X) _m or G —Ο — Ρ — Ο R (X) ₁₁ O - R (X) _n ,
GOP = O O - R (X) _m in which G is an alkylene radical, m is 1 to 4 and η is 0 to 4. Considered publications:
German Auslegeschrift No. 1 043 630;
U.S. Patent No. 2,591,884. 409 558/467 3.64 © Bundesdruckerei Berlin