DE1219672B - Process for the production of rigid, flame-retardant polyurethane foams - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

C08g

German class: 39 b -22/04

Number: 1219 672

File number: P 33346IV c / 39 b

Filing date: January 10, 1964

Opening day: June 23, 1966

The invention relates to a process for the production of new flame-retardant rigid polyurethane foams.

The usual hard polyurethane foams are very easily inflammable. Since foams for the construction or insulation sector often have to comply with regulations relating to fire resistance, rigid polyurethane foams cannot be used for many purposes. Attempts to improve the flame resistance of rigid polyurethane foams by ¹ ^ admixture of inert additives, were not entirely successful, because if the amounts of the additives are high enough to make the foam undergo example, self-extinguishing, their presence impairs the mechanical properties of the foam.

It is known that polyurethane foams are made from branched polyhydroxyl compounds and combinations of polyisocyanates, including halogen-containing polyisocyanates named ao are. However, it was not known that a specific selection in the compilation of the Polyisocyanate mixtures can win flame-retardant foams, which in addition to the required flame resistance have unchanged good mechanical properties.

It is also known to make polyurethane foams using intermediate compounds containing substituents which should improve fire resistance. Intermediate compounds that have become known for the production of polyurethanes with improved flame resistance include ring halogenated aromatic diisocyanates. However, the production of rigid polyurethane foams from ring halogenated aromatic diisocyanates is associated with various difficulties. When a foam is produced using prepolymers, the isocyanate-modified polyhydroxyl compounds required are highly viscous or even solid and therefore difficult to handle and meter. If the one-step or direct process is used, in which all reaction components are brought together at the same time, the halogenated aromatic diisocyanates have to be brought to elevated temperatures because of their relatively high freezing points. This is particularly inconvenient when foaming is desired on site, as is often the case in the manufacture of building insulation. In addition to the problem of storing and handling these diisocyanates at elevated temperatures, it may be feared that processes for the production of rigid ones
flame retardant polyurethane foams

Applicant:

E. I. du Pont de Nemours arid Company,

Wilmington, Del. (V. St. A.)

Representative:

Dr.-Ing. A. v. Kreisler, Dr.-Ing. K. Schönwald,

Dr.-Ing. Th. Meyer

and Dipl-Chem. Dr. rer. nat. J. F. Fues,

Patent attorneys, Cologne 1, Deichmannhaus

Named as inventor:
Howard Emil Holmquist,
Wilmington, Del. (V. St. A.)

Claimed priority:
V. St. v. America January 15, 1963
(251501)

the mixture to be foamed when it is introduced in the hot state into the highly exothermic one-stage system reached such extreme temperatures that the quality of the foam formed is impaired will.

The invention is based on the object of eliminating the disadvantages mentioned above. This is achieved according to the invention by a process for producing rigid, flame-retardant polyurethane foams from diisocyanate mixtures containing aromatic halogen-containing diisocyanates and branched polyhydroxyl compounds with at least three hydroxyl groups in the molecule, with flame retardants and blowing agents, and this process is characterized in that a diisocyanate mixture with a content of at least 2.5 percent by weight of nucleus-bonded halogen and with a solidification point below 26 ⁰ C is used and that if the halogen content X is below 7 percent by weight

1 14 '\
is, \ -y - 2) to 6 percent by weight of antimony in the form of antimony trioxide or triarylstibines, all weight numbers referring to the total

'609 580/445

weight of isocyanate mixture and polyhydroxy compounds are related.

In the direct system used in the context of the invention, all reaction components are brought together at the same time, usually in a mixing chamber, whereupon the mixture from the Chamber is passed and then cured. The mixture in the chamber is foamable Mass made up of the following components:

10

a) About 0.90 to 1.20 equivalents of an organic polyhydroxyl compound with at least three Hydroxyl groups in the molecule and a hydroxyl number of 350 to 650;

b) one equivalent of a mixture of aromatic diisocyanates with a congealing point of less than about 26 ° C, at least one of the diisocyanates being ring chlorinated and / or ring brominated aromatic diisocyanate and the halogen concentration calculated on the Total weight of polyhydroxyl compound and diisocyanate mixture is at least 2.5%,

c) an inert liquid propellant;

d) small catalytic amounts of a tertiary amine and / or an organic tin compound;

e) small amounts of foam-stabilizing surfactants, and

f) 0 to 6.0% antimony, based on the total weight of polyhydroxyl compound and diisocyanate mixture, the antimony being in the form of antimony trioxide or triaryl stibines. When the content of ring halogens is less than 7 percent by weight is the amount of antimony

at least - = - 2, where X is the amount of halogen

as a percentage of the total weight of the polyhydroxyl compound and diisocyanate.

According to the method according to the invention, flame-resistant, hard polyurethane foams are obtained, which the reaction product of the components mentioned above under a) to f) in the there represent the specified amounts.

For the purposes of the invention, mixtures of two or more diisocyanates are suitable, of which at least one must contain a halogen atom substituted on the aromatic nucleus. The halogen can be chlorine or bromine. The quantitative ratio of the diisocyanates must be chosen so that the The mixture of diisocyanates contains so much halogen that the halogen concentration, based on the Total weight of polyol and diisocyanate mixture is at least 2.5%. Furthermore, the quantity ratio to be chosen so that the mixture is liquid under normal conditions or a freezing point which is so low that the storage, handling and dosage under the intended working conditions be relieved.

As components for the preparation of the liquid mixtures to be used in the context of the invention A wide variety of non-halogenated aromatic diisocyanates can be used. As examples are named: tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, 1,3-phenylene-diisocyanate, cumene-2,4-diisocyanatej 4,4'-diisocyanatodiphenylmethane, 4,4'-diisocyanatodiphenyl ether, Naphthylene-1,5-diisocyanate, 4,4'-diisocyanatobiphenyl, 3,3-'dimethyl-4,4'-diisocyanatodiphenylmethane.

The halogenated diisocyanates suitable for the purposes of the invention can contain chlorine or bromine which is bonded directly to the aromatic nucleus. Mono-, di- or polyhalogenated aromatic diisocyanates are suitable. Examples of such suitable diisocyanates are given below, the melting points being given at the same time. It should be noted that the melting point of all these compounds is well above room temperature (about 26 ^° C.).

Melting point, ⁰ C

5-chlorotolylene-2,4-diisocyanate ... 62.8 3-chlorotolylene-2,6-diisocyanate ... 47.9 3,5-dichlorotolylene-2,4-diisocyanate 62.9 3,5-dichlorotolylene-2,6-diisocyanate 80.4

5-bromotolylene-2,4-diisocyanate 64.9

3-bromotolylene-2,6-diisocyanate 59.2

S ^ -dibromotoluylene ^^ - diisocyanate 86.9 3,3'-dichloro-4,4'-diisocyanatodiphenyhnethane 101 to 102

cyanate 105.7

or

Tetrachloro-m-phenylene diisocyanate 76 to 78

The required halogenated diisocyanates can be prepared by direct halogenation of the starting diisocyanate or by phosgenation of the halogenated diamine. Generally will the halogenation of the diisocyanates in the case of the tolylene diisocyanates and phenylene diisocyanates in known to be preferred. In the case of compounds such as 3,3'-dichloro-4,4'-diisocyanatodiphenyl or 3,3'-dichloro-4,4'-diisocyanatodiphenylmethane, in which the starting amines are readily available, however, is the Phosgenation of the amines is preferred.

The halogenation of aromatic diisocyanates or the phosgenation of halogenated amines can be carried out according to generally known methods.

All polyhydroxyl compounds normally used in the production of the usual rigid polyurethane foams are suitable can also be used for the production of the foams according to the invention. These polyhydroxyl compounds contain at least three hydroxyl groups in the molecule and have an OH number of about 350 to 650. This OH number range is preferred because with polyhydroxyl compounds whose OH numbers are below about 350 are, semi-rigid foams are obtained, while with those whose OH numbers are above around 650 lie, brittle or crumbly foams are formed. Come for the purposes of the invention Both polyalkylene ether polyols and polyesters are in question, but the polyethers are made from economical ones Reasons particularly preferred.

The polyalkylene ether polyols can have been prepared by condensation of lower alkylene oxides with low molecular weight polyols. the Condensation products of ethylene oxide, 1,2-propylene oxide or their mixtures with polyols, such as Glycerine, 1,1,1-trimethylolpropane, 1,2,6-hexanetriol, Sorbitol, or sucrose, are representative examples of polyalkylene ether polyols. Are also suitable

5 6

Condensation products of alkylene oxides with adjusted foams if their halogen content bonds, such as ethanolamine, diethanolamine, ethy- at least about 7 percent by weight, one lenediamine or diethylenetriamine. The production of significantly higher flame resistance than foams, of polyoxyalkylene compounds including the diisocyanates used in their production, Polyalkylene ether polyols are in U.S. Patent 5 which contain no halogen substituents. Foam writing 3,030,426. substances containing less than about 7% halogen from the

For the purposes of the invention, the aromatic diisocyanate can contain, although a wide variety of polyesters are still used, for example a certain improvement in flame resistance from a) dibasic acids, such as succinic acid, compared to known products, but these ver Sebacic acid, azelaic acid improvement is of limited value. It has been shown or mixtures thereof with b) glycols, such as ethylene, that foams which contain less than 7% glycol, propylene glycol or diethylene glycol, and c) halogen have high flame resistance to polyhydric alcohols which can be borrowed at least three hydroxyls when an antimony compound contains groups, e.g. B. glycerol, pentaerythritol, tri- is added in an amount that depends on the methylolpropane, mannitol or sorbitol. The OH number 15 is calculated using the following formula:
and functionality of the polyester depends on the mol- 24

Ratios of the dibasic acid and the glycol antimony in% = ~ γ 2.

and the low molecular weight, at least trivalent

Polyols from which to prepare the polyester comparable I _n of this equation is X, the amount have been ring applies. The total equivalents of the substituted halogen from the diisocyanate, based on glycol and this polyol, must exceed the equivalents based on the total weight of diisocyanate and polyhydric acid, so that the finished polyester hydroxyl compound. In foams with increasing terminal hydroxyl groups. Polyesters with this halogen content, from about 2.5 to 7%, must be prepared in the usual way according to Art, decreasing amounts of antimony are added to this equation, namely by heating the mixture of the acid with 3.6 up to 0%, in order to produce products the glycol and this polyol with or without one obtained, which is a substantial improvement in the esterification catalyst with removal of the water flame resistance over the regular, not progressive esterification. Incorporated containing halogenated diisocyanates

When show high requirements with regard to the Ent-Polyurethanes. In the case of a halogen content of flammability of the foam, 3 ° 7% ° whichever is higher, the equation for the antimony, chlorine, bromine or phosphorus-containing poly- need gives a value of 0 or negative values. hydroxyl compounds, such as those described in the negative values and 0% indicate that British patent 873 974, in the Belgian no antimony is required to produce foams, patent specifications 602 498 or 604 815, the flame resistance of which is considerable, in connection with the according to the invention 35 is higher than in the regular, halogen-containing liquid diisocyanate-produced polyurethane foams not used according to the invention. In practice, mixtures can be used. To achieve increased flame resistance, up to 6.0% antimony can also be added to each foam material, chlorine or phosphorous, which contain at least about 2% halogen phosphorus-containing additives, however, including foams with halogen, generally deteriorate the 4 ° held at 7 ° / ₀ or more. By varying the mechanical properties. When calculating the content of halogen which was introduced with the aromatic required amount of antimony according to the above-mentioned diisocyanate, and the amount of the formula, halogen which is not added in the form of halo-present antimony, flame-resistant diisocyanates can not be added within a wide range Area with hard consider. Compounds of this type include 45 foams which are produced by the direct process of the halogen-containing liquid propellants. The series of these foams will be discussed later. substances range from those that are considerably slower

The amounts of liquid to foams used for the inventive production of the burn as corresponding known foams, foams that are in the sense of the ASTM diisocyanate mixture and polyhydroxyl compound are 5 ° method D-1692-59 T (measurement of flammability to be measured so that the Ratio of isocyanate to foam) are non-burning,
groups to OH groups of the polyhydroxyl compound If antimony is about 1 according to the invention. It is preferable to add about 0.9 to about 0.9 to 1 foams, it is used in the form of 1.20 OH groups per isocyanate group. an antimony compound, namely as antimony-It can also be added higher amounts of OH groups trioxide or as triarylstibine. The triaryl used, however, the stibines obtained here have the general formula Ar ₃ Sb, in which foams usually have a lower compressive strength. Ar is an aryl radical, e.g. B. phenyl, p-toluyl or speed and poorer dimensional stability. One can also use p-chlorophenyl radical. Any finely divided anti-less than 0.90 equivalents of OH of the polyhydroxyl montrioxide, which use compound per equivalent of diisocyanate in the manner described below, is added to the foam, is suitable. The triarylstibines, however, this is disadvantageous, since the diisocyanates required can easily be incorporated into the compositions to be foamed, are generally more expensive than those that are poorly combined before foaming either polyhydroxyl compounds and the physical properties in the diisocyanate mixture or in the polyhydroxyl properties of the foams obtained be solved,
are. 65 The formation of the pores in the

The foams produced by the method according to the invention under according to is with the help of a

Use of halogenated aromatic diiso- inert, liquid propellant takes place in the

diisocyanate mixtures containing cyanates. Temperatures and pressures at which the

7 8

mixture with the ingredients to be foamed, each alone for the production of the invention occurs, is liquid and that evaporates when the print is used foams, however it is common is lowered and / or the temperature of the show mixtures of these two types of catalyst to use, menden mixture increases by the reaction. This is preferably used in accordance with the invention means that any liquid which is in the range of about 0.1 to 0.3 parts of stannous 2-ethylhexanoate in boiling about -20 to 80 ° C, can be used, combination with about 0.4 to 1.2 parts of triethylene so long they do not use the foaming system diamine per 100 parts of polyhydroxyl compound. if reacted. Such mixtures of liquids also use the two catalysts alone can be used if their boiling points are, the amount used must be higher than are in the appropriate temperature range. A large io suggests the combined catalyst system. Number of liquid propellants can be used in the production of polywids according to the invention, z. B. butane, pentane, chloroform, acetone, urethane foams by the direct method Carbon tetrachloride or diethyl ether; but just as in the production of the usual foam fluorinated derivatives of aliphatic carbons by the direct method surface-active Hydrogen preferred. The products are easily required on average. The surfactant Commercially available, and some of them are used to stabilize the foam during the boiling phase required area. They are chemically proportional foaming and contributes to the formation of a uniform inert and non-flammable and may result in the more moderate end product. Several types of Flammability of the finished foams slightly surfactants, which are already suitable to decrease. 20 have been proven for foam production are also

Trichlorofluoromethane can be used as a liquid propellant for the purposes of the invention. For this for the foams according to the invention particularly include a) nonionic surface-active agents, preferred. The amount of these compounds to be used by sequential addition of propylene bond is about 10 to 30%, based on the oxide and ethylene oxide to compounds such as total ethylene weight of diisocyanate plus polyhydroxyl diamine or propylene glycol, b) poly compound. When using other liquid propellant dimethylsiloxane polyalkylene ether block polymers, the medium are approximately equimolar amounts corresponding to slow hydrolysis, and c) verden Use amounts of trichlorofluoromethane. turned polydimethylsiloxane polyalkylene ether block

It is customary to foam in the presence of copolymers that have been modified so that they

Make catalysts that resist the reaction of the hydrolysis. Of these different

Diisocyanate and the polyhydroxyl compounds are the types of surfactants

speed up. For the production of polyurethane polydimethylsiloxane polyalkylene ether block mix

Foams usually become two general polymers that are resistant to hydrolysis, in particular

Catalyst types used. The first type preferably includes.

the tertiary amines, for example N-ethylmorpholine, 35 the nonionic surface-active agents, the

1,3-bis (dimethylamino) butane or triethylenediamine. by successive addition of propylene

Organic tin and ethylene oxide belong to the second type. to compounds such as ethylenediamine

connections, e.g. B. dibutyltin dilaurate or stannous or propylene glycol, can be prepared by

2-ethyfhexanoate. These two catalysts can be given the following formulas:

CH ₃

H (C ₂ H ₄ OMC ₃ H ₆ O) SO - CH ₂ -CH-O (C ₃ H ₆ OMC ₂ H ₄ O ^ H
or

rr / f tr / -Vv (C * ττ r \\ (C * TJ CW (C * TU fW TU "

.Μ \ * ^ ₂ Γ1 ₄ υ ^ 2 / ^ ₃ Γ1 ₆ ^:!;. , ^ ₃ JHL ₆ VJJaJ ^ ₂ Jl ₄ UJjZiI

HCH ₂ CH ₂ N ^

H (C ₂ H ₄ O) ₂ Z (C ₃ H ₆ O) * ^ C ₃ H ₆ OMC ₂ H ₄ O) ₂ ZH

Here χ is the number of propylene ether residues and y Belgian patent specification is 603,552. Like the number of ethylene ether residues. Surfactants mentioned, these surfactants are resistant to agents with molecular weights from 1200 to 3000 and hydrolysis and less difficult to handle. Ratios of χ to y of 1: 1 to 7: 1 are most suitable for making the flame retardant foam purposes of the invention. 55 fabrics according to the invention can be about 0.5 to 2 parts

The polydimethylsiloxane polyalkylene ether block, one of the types of surface copolymers mentioned above, those of hydrolysis, underhegen- active agents per 100 parts of polyhydroxyl compound can be made by the process used in FIG. With the water-soluble organoder U.S. Patent 2,834,748. silicone polymers that resist hydrolysis, The 60 described in Example I (a) of this patent specification gives excellent results when Block copolymers in this class are preferably about 1 to 1.3 parts per surfactant added surfactants can be used for the purpose of 100 parts of polyalkylene ether polyol. Invention. However, related block details about foam stabilizers and copolymers can be used. Catalysts are in »Rubber Chemistry and Techno-

Particularly preferred for the method according to 65 logy ", Vol. 33, pp. 1293 to 1322 (1960) to be found.

Invention are similar polydimethylsiloxane-poly- The foams made in accordance with the invention

alkylene ether block copolymers, which can be processed according to the same methods as the usual

are made as they are made, for example, the subject of polyurethane foams.

9 10

The direct method can be flame-retardant foam method lies in the use of a double substance be produced in batches by an acting, inert liquid propellant consisting of two Mixture of the polyhydroxyl compound, the catalyst or more liquids of different boiling points, surfactant and liquid blowing point. This propellant will work with the others by means of and finally the mixture with the 5 components of the mixture to be foamed liquid diisocyanate mixture, which mixed a suitable Ha- overpressure, whereupon the pressure under which contains logen amount, is added. When antimony - the whole mixture is standing, it is lowered. One of the trioxide is used, it is best added to the component of the double-acting propellant Mixture of polyhydroxyl compound, catalysts, is chosen so that it is under the conditions of Surface-active agent and propellant to and io pressure reduction evaporated immediately and distributed here it well before the diisocyanate mixture is added when a foam of medium density is formed, will. After the addition of the diisocyanate, the foam is replaced by the second and higher mixture stirred until it becomes creamy, and then immediately continue to expand the boiling component of the propellant Cast a suitable mold in which to expand it as soon as this component is a consequence of the foams. The exact order of addition 15 temperature rise caused by the reaction of the Dider Ingredients is not essential, but if the isocyanate occurs with the polyhydroxyl compound, Diisocyanate and the polyhydroxyl compound is evaporated. This process involves mixing an addition of any other necessary mixtures of dichlorodifluoromethane and trichlorofluorous must be added Ingredients take place quickly before a nominal methane is preferred as a double-acting propellant, worth reaction has taken place. The foams according to the invention can according to The "direct foams" according to the invention are applied by spraying. This kind can also be carried out continuously in the usual way be made that foam of irregular surfaces or at the same time two or more sub-components one with intensive walls. Mixer where the mixing process Feed in the mixing chamber provided with a stirrer. That takes place from 25 inside, and mixers where the comer Mixing chamber exiting mixture will be mixed in components outside, can be used in the case of the syringe Forms or cavities can be entered or used on procedures. With the internal mixers a moving tape is deposited. In another process, two or more components are mixed before drive, the total mixture is atomized for continuous according to the invention. To complete Manufacture of flame-resistant polyurethane foam or partial mixing of the materials before the materials can be applied, the following atomization can avoid mechanical devices Streams of a mixing chamber are metered: are turned, d. i.e., one does not rely on them

Fluid turbulence alone. Carry the external mixers

Stream 1 ^two i ° of the more components separated into one decomposition. ,,,,. , ^ ,, 35 dusting air stream, to which only the polyhydroxyl compound, catalysts and the _{task of} mixing falls. In order to produce foam surfactant and liquid blowing agent in _{accordance with the} invention, both mixers can all be mixed prior to use. In comparison _t be _Verweij friend, but the inward-of antimony trioxide can be likewise this _{mixer bevorzugtj because they have a less air to.} if added to this stream by _{requiring proper} mixing of the components, the other subcomponents prior to use. _{It is important that the air} required for mixing be mixed. is kept as low as possible, since a ^ " _T ",. _. _. A liquid propellant such as trichlorofluoromethane is used. The mixture _{45, which is liquid under normal conditions, is used when large amounts of} air are used

of diisocyanates ^ _for mixing the foam components in

is evaporated and lost to a considerable extent.

The method described above is of course that this loss of propellant can be avoided by adding mechanical point of view very simple, however additional amounts of propellant can be added before mixing Occasionally more complicated arrangements may expediently be supplemented 50, but this is one with material. For example, the liquid propellant can be wastefully and expensive to operate separate stream introduced directly into the mixing chamber most spray mixers only have two streams of parts will. This often happens when the Her- components can merge, it can for the position of foams using spray application may be required that the one stream from Trichlorofluoromethane as a propellant, because this easily 55 the normally liquid diisocyanate mixture and volatile material normally in low pressure gas - the second stream of all remaining components bottles that make up it on. This way of working is similar to that already most expedient is consumed directly. Apparatus, described continuous foam production. which are used for continuous dosing and mixing Individual components of polyurethane foam- 60 made new flame-resistant foams are not detailed in the brochure about the transfer to the tack-free state HR-32 of the inventor »Metering and Mixing Equipment to be cured at elevated temperatures, for the Production of Urethane Foam Products «by Although it is hardened in a heating cabinet S. A. S t e w a r t, September 1958. 70 to 120 ° C for a period of 1 to 4 hours the

The foams produced according to the invention 65 adjust their ultimate physical abilities can also be produced by the process, shafts are accelerated, but the foam can reduce the that in "Chemical Engineering Progress", 57, No. 10, same hardening state also at room temperature-1961, Pp. 40 to 46 is described. The principle of this temperature can be achieved within a period of 1 day or longer.

11 12

are sufficient. However, the tack-free state becomes after the foam sample is at a distance of 2) 54

Foaming even without hardening in the heating cabinet and marked 12.7 cm from the lit end,

reached in a few minutes. The time it takes for the flame to move from the 2.54 cm

As mentioned earlier, the after the Ver mark is found to progress to the 12.7 cm mark

drive according to the invention produced flame 5 measure of the flame resistance. This burning rate

adverse rigid polyurethane foams as insulation Density is usually expressed in cm / min. the

Use wherever there is a need for fire resistance of rigid foams produced according to the invention *

arrives. Of course, these foams are on ben a much slower burn rate

Because of this flame resistance, it is particularly interesting than the regularly produced polyurethane foams,

for the insulation of residential and commercial buildings. io If the foam stops burning before the

It has already been noted that the 10.2 cm long part according to the invention between the marks on the

If the foam is used up on site for the cavity foam sample, the foam is used

Filling or for coating surfaces is regarded as self-extinguishing. More details

possible. about this test are published in 1959

In the following examples, the supplement to the ASTM methods, part 9, refer to

Quantities are based on weight, unless otherwise found. For some foams with exceptional

stated "high flame resistance, the test was modified, by testing the foam sample with a

Example 1 clamp held vertically and then at the bottom

20 end was flamed with the burner. This loading

A number of foams will batch conditions are much more severe than the ASTM test

according to the classification D 1692-59 T described below to determine the flammability. It

process produced, it should be noted in the table that foams, the considerable

named and in the footnotes to this table are halogen quantities and about 1 to 2 parts by weight

the specified ingredients and quantities used contain 25 antimony trioxide, are self-extinguishing,

will. The required mixtures of diiso- even when tested in a vertical position,

cyanates are made by melting the chosen di- The last foam in the table is so flammable

isocyanate in the desired proportions, against the fact that it is in accordance with ASTM D 1692-59 T

Mixing and cooling the mixtures to about room-non-flammable.

temperature produced. The foams are produced from the diisocyanate mixtures given in the table by the density and compressive strength values are measured on cylindrical surface-active agents, the polyhydroxyl compound and test specimens that are cut with a die of the diisocyanate mixture in a suitable container with which a cylinder of 2.87 cm must be weighed. Pre-weighed amounts of liquid diameter is obtained. At this diameter propellants and catalysts become as fast as 35 the cross-sectional area is 6.46 cm ² . In order to make it possible, the mixture is added with a tuning of the volume weight, the height of a high-speed stirrer 10 to 30 seconds, such a cylinder is stirred vigorously with one gauge up to the next. When using antimony trioxide, measure 25 μ and weigh the sample. With these, its addition is also carried out in a pre-weighed number, the volume weight can easily be determined, the amount together with the liquid propellant and 40 which is usually expressed in kg / m ³ . The the catalysts before stirring. After the short compressive strength, the mass is determined in a modified Instron mixing time in a mold or in a testing machine, with which a steadily increasing suitable container is poured. The foam begins to increase pressure on one end of a standard cylinder almost instantly and reaches its foam with a cross-sectional area of 6.46 cm ² maximum height in about 1 to 7 minutes. The foam 45 and a height exerted by at least 2.55 cm, fabrics are then 1 hour at 120 ⁰ C in a heating The testing machine recorded the compression cabinet with circulating air cured. of the foam with increasing pressure. Until that

The values in the table are given in groups - the point at which the foam collapses is

which represent certain diisocyanate mixtures. the change in sample length with increasing pressure

These groups are in turn arranged so that, in 50 small. At the pressure that has the compressive strength of the

the table from top to bottom, which corresponds to Diiso foam, however, finds a quick one

cyanate mixtures contain increasing amounts of halogen. Change of the sample length takes place. This fast one

It is generally stated that the foams, change in length corresponds to the collapse of the

which contain the highest amounts of halogen, the foam structure or the complete break

have the highest flame resistance. It is also 55 of the foam sample tested,
to note that with increasing amount of halogen, smaller amounts of antimony trioxide are required,

to achieve the same flame resistance. Example 2

The flame retardancy and specified in the table

Burn rate of the cured foams 60 A ternary mixture of diisocyanates is used measured according to ASTM method 1692-59 T. Known way as follows: Man mixes 20.7 parts In this test, one end of a foam sample becomes trichloro-TDI, 53.4 parts dichloro-TDI, and 29.5 parts of 15 x 5 x 1.3 cm with a slot nozzle burner an-TDI in a container, heat the mixture until all ignited. The foam rests on a component that is melted and mixes well Sieve, which has a mesh size of 6.2 mm and 65 and cools the mixture to room temperature. the Steel wire of 0.8 mm diameter is made. mentioned diisocyanates are in the footnotes to The foam is given enough opportunity, as described in the table. This mixture from Diisosich to ignite, and then remove the burner. cyanate contains 53.5% chlorine.

14th

ST "*
¹ p NS 'S S ' so 60 43 ■ search no ssiges
socyanat socyanai
most important IT S δ 0 TDI 21.0 1 A. 21.0 2 A. 23.4 3 B. 23.0 4th B. 11.4 5 B. 24.5 6th C. 25.0 7th C. 25.0 8th C. 25.0 9 C. 25.0 10 D. 24.0 11 D. 25.3 12th D. 25.0 13th D. 25.0 14th D. 25.0 15th D. 25.0 16 D. 27.3 17th D. 25.0 18th D. 25.0 19th E. 25.0 20th E. 25.4 21 F. 25.0 22nd F. 25.0 23 G 28.4 24 G 28.0 25th G 28.0

Polyhydroxyl

connection ³ )

Sl.

■ Sun 1

Antimony trioxide

* -> Self-out 1
S3 1 erasing ta • 6 ti win Ö - renngescl
n / min. ύ
H
t / 3 no PP 3 - 16.8 no - 3.3 Yes - 4.8 Yes - 3.3 Yes - 3.05 Yes no 10.4 no - 1.3 Yes - 9.9 no - 6.1 Yes - 6.9 no Yes 2.8 Yes Yes 6.6 no - 6.1 Yes - 3.6 Yes -. 0.76 Yes - 0 Yes* 6.4 no - 3.3 Yes - 3.6 no - 11.7 no - · 5.8 Yes no 8.1 no Yes 3.6 Yes 5.3 Yes 3.8 Yes 0 Yes*

487
448
480

448
480
480

483
483
480
480

449
429
480
480
480
480
480
480
480

483
502

448
448

483
480
480

29.9 27.6 27.8

26.9 12.1 26.0

26.8 26.8 27.0 27.0

26.8 28.3 26.4 26.4 26.4 26.4 28.4 26.4 26.4

25.3 24.8

25.0 25.0

23.2 23.0 23.0

AWAY

Ba)

A A B B

Ac)

AWAY

A A

A B B

12th

12th

5 12

12 12 12 12

7 7

12 12 12 12 12 10 10

10

12th

10 10

10 10 10

B A B

Ba)

Bb) Bb) B B

A A B B B B B B B

B B

AWAY

B B B

0.0

3.4 3.7

8.4 9.0 9.1

9.7

9.9

9.8

10.3

9.9 10.1 10.6 10.4 10.2 10.0 10.6 10.6 10.6

12.0 12.2

15.3 15.2

21.4 21.8 21.4

3.5 1.5

1.6 0.15

0.91 0.2

0.99

1.0 2.0 3.0

0.4

1.0

5.5
2.3

2.6
0.5

1.4
0.3

1.6

1.6
3.1
4.6

32.04 41.17

- 37.81

33.32

30.92 29.32

36.04

49.02 46.46 31.24 33.8

0.7

1.6

32.36 32.84

36.21 37.17

33.96 40.05

43.73

* Non-flammable according to ASTM-1692-D.

*) The following surfactants and tertiary amines were used in the production of the foams listed in the table used as catalysts: surfactants

Type A: Polydimethylsiloxane-polyalkylene ether block copolymer according to Example I (a) of US Pat. No. 2,834,748. Type B: Polydimethylsiloxane-polyalkylene ether block copolymer according to Belgian patent specification 603 552:

Type C: Nonionic surfactant made by sequential additions of about 23.9 parts of propylene

oxide and 4.3 parts of ethylene oxide to 1 part of propylene glycol.
Type D: Nonionic surfactant made by sequentially adding about 21.7 parts of propylene

oxide and 7.2 parts of ethylene oxide to 1 part of propylene glycol.

Tertiary amines as catalysts type A: 1,3-bis (dimethylamino) butane. Type B: triethylenediamine.

Unless otherwise stated in the columns headed "Surfactant" and "Tertiary amine", the following were used for all experiments used 0.3 part of surfactant, 0.14 part of tertiary amine and 0.05 part of stannous 2-ethylhexanoate.

a) 0.17 part surfactant, 0.07 part tertiary amine catalyst.

b) 0.21 part of tertiary amine, 0.10 part of stannous 2-ethylhexanoate.

c) 1.1 parts surfactant.

² ) The liquid diisocyanate mixtures used had the following composition and properties:

A = 50 parts of monochloro TDI and 50 parts of TDI; 8.5 ° / "halogen in the mixture, solidification point about 20 ⁰ C.

B = 60 parts of monobromine TDI and 40 parts of TDI; 18.9 ° / ₀ halogen, freezing point about 18 ° C.

C = 53 parts of trichloro-TDI and 47 parts of TDI; 20.7% halogen; the mixture did not solidify when left at about 25 ° C for 3 days

was left standing.

D = 75 parts of dichloro-TDI and 25 parts of TDI; 21.9% halogen, freezing point about 24 ^° C. E = 60 parts dichloro-TDI and 40 parts monochloro-TDI; 24.3% halogen, freezing point about 24 ^° C. F = 66.7 parts dichloro-TDI and 33.3 parts monobromo-TDI; 30.8% halogen, freezing point about 25 ^° C. G = 47 parts dibromo-TDI and 53 parts monobromo-TDI; 39.3% halogen, freezing point about 25 ^° C. The diisocyanates used to prepare the above-mentioned mixtures can be described as follows: TDI = mixture of about 80 parts of toluene-2,4-diisocyanate and 20 parts of toluene-2,6-diisocyanate . Monochloro-TDI = distilled product from the chlorination of TDI with about 1.2 moles of Cl ₂ per mole of TDI.

Dichloro-TDI = distilled product from the chlorination of TDI with about 2.4 moles of Cl ₂ per mole of TDI. Monobromo-TDI = distilled product from the bromination of TDI with about 1.05 moles of Br ₂ per mole of TDI.

Dibromo-TDI = distilled product from the bromination of TDI with about 2.10 moles of Br ₂ per mole of TDI.

Trichloro-TDI = distilled product from the chlorination of TDI with about 3.6 moles of Cl ₂ per mole of TDI.

³ ) The polyhydroxyl compounds used were polyalkylene ether hexites with average molecular weights of about 750, produced by reacting 1 part of sorbitol with about 3.1 parts of propylene oxide.

In the manner described in Example 1, a foam is produced by mixing 25.0 parts of the ternary mixture with 25.9 parts of polyhydroxyl compound (described in Example 1, OH number 480), 12 parts of trichlorofluoromethane, 0.3 parts of surfactant B. (See Example 1), 0.14 part of triethylenediamine and 0.05 part of stannous 2-ethylhexanoate. After curing in the heating cabinet at 120 ° C, the foam contains 11.5% chlorine and is self-extinguishing in the sense of ASTM D-1692-59T at a burning rate of 5.84 cm / min. It has a density of 33.64 kg / m ³ and a compressive strength of 1.97 kg / cm ² .

Example3

About 28.2 parts of a polyester glycol (OH number about 431, prepared in the usual way from 1998 parts of phthalic anhydride, 1971 parts of adipic acid, 4824 parts of trimethylolpropane and 954 parts of diethylene glycol), 16 parts of chloroform, 1.0 part of antimony trioxide, 0 15 parts of 1,3-bis (dimethylamino) butane and 0.03 part of stannous 2-ethylhexanoate and 0.3 part of surface-active agent A (see Example 1) are stirred to form a uniform mixture. About 24.0 parts of a diisocyanate mixture which had been prepared from 3 parts of dichloro-TDI and 1 part of TDI (see footnote to the table) are added to this mixture. After the addition of the diisocyanate, the mixture is stirred vigorously for about 30 seconds and poured into a mold for foaming. The foam is cured at 120 ° C. for 4 hours. After a storage time of 2 days at room temperature, the foam is self-extinguishing according to ASTM 1692-D-59 T. The foam contains 9.8% chlorine (excluding the chlorine contained in chloroform) and 1.9% Sb ₂ O ₃ according to 1 , 6% antimony. Its burning speed is 38 mm / min.

Example 4

40

A liquid mixture of diisocyanates is in known way produced by 76 parts of dichloro-TDI (see footnote to the table) and 24 parts of crude 4,4'-Diisocyanatodiphenylmethane can be heated in a container until all of the material has melted is, followed by mixing and cooling to room temperature. The crude 4,4'-diisoeyanatodiphenylmethane has a purity of 84%> determined according to ■ the method described in ASTM D 1638-60 T. In addition to 4,4'-diisocyanatodiphenylmethane, the crude mixture contains tars and by-products that formed during phosgenation, and polyisocyanates that are formed during phosgenation of polyamines arise at the same time during the production of the diamine required for the phosgenation had been formed.

In the manner described in Example 1, a foam is made by mixing 26 parts of the liquid diisocyanate mixture with 24.4 parts of polyhydroxyl compound (see Example 1, OH number 457), 12 parts of trichlorofluoromethane, 0.3 part of surface-active agent B (see. Example 1), 0.14 part of 1,3-bis (dimethylamino) butane, 0.5 part of stannous 2-ethylhexanoate and 1.0 part of antimony trioxide. The foam made from these components is self-extinguishing in the sense of ASTM D-1692-59 T. kg / m ³ and contains 11.5% chlorine and 1.9% Sb ₂ O _3, corresponding to about 1.6% antimony.

Example 5

A mixture of about 100 parts of a polyether polyol (as in the example 1, OH number 480), 2 parts of surface-active agent (type B according to Example 1), 0.65 parts of triethylenediamine, 0.2 parts of stannous 2-ethylhexanoate and 33 parts of trichlorofluoromethane in a known manner manufactured. A mixture of about 3 parts of dichloro-TDI and 1 part is placed in a second storage container TDI (see example 1) given. These mixtures are supplied as separate streams with a high speed stirrer provided mixing chamber in such amounts that about 101 parts of diisocyanate mixture 135.8 parts of the mixture of | polyhydroxyl compound, surfactant, catalysts and propellant are fed. Suitable apparatus for metering and mixing these two streams are described in detail in the aforementioned brochure HR-32 by the inventor.

The homogeneous mixture of the components from the mixing chamber is introduced into suitable containers, where it is foamed and allowed to harden until it is tack-free. After curing for 1 hour in a heating cabinet at 120 ° C. and aging for 2 days at room temperature, the foam has a density of 28.84 kg / m ³ and a compressive strength of 1.82 kg / cm ² . At a burning rate of 8.13 cm / min, it is self-extinguishing according to ASTM 1692-D-59T. Its halogen content is 10.8%.

Example 6

A foam which contains antimony added as triphenylstibine is made from the diisocyanate mixture D and the polyhydroxyl compound mentioned in the table. About 1.6 parts triphenylstibine are dissolved in 24.5 parts of the polyhydroxyl compound. The solution is mixed with 24.5 parts of diisocyanate, 12 parts of trichloromonofluoromethane ,. 0.3 parts of surfactant (type B according to table), 0.14 part of triethylenediamine and 0.05 part of stannous 2-ethylhexanoate are mixed. On the in example 1 A foam is produced from this mixture, which contains 10.6% halogen and Contains 1.07% antimony. At a burning rate of 3.8 cm / min, the foam is self-extinguishing in terms of ASTM-1692-D.

A similar foam is made from a solution of 1.5 parts of triphenylstibine in 23.7 parts of the Polyhydroxyl compound and 25.2 parts of a diisocyanate mixture prepared by mixing 28 parts of TDI was obtained with 72 parts of a product made by adding 1 mole of TDI halogenated first with 1 mole of bromine and then with 1.5 moles of chlorine. This foam contains 15.3% halogen and 1.02% antimony. It has a burning speed of 3.56 cm / min and is self-extinguishing in the sense of ASTM 1692-D when tested in a vertical position.

Claims (1)

Claim: Process for the production of rigid, flame-retardant polyurethane foams from aromatic tables containing diisocyanate mixtures containing halogen-containing diisocyanates and branched polyhydroxy compounds with at least three hydroxyl groups in the molecule with flame retardants and blowing agents, characterized in that a diisocyanate mixture with a content of at least 2.5 percent by weight of nucleus-bound halogen and with a solidification point below 26 ⁰ C is used and that if the halogen content X is less than 7 weight j ο (14 \
-y- 2] to 6 percent by weight Antimony is used in the form of antimony trioxide or triaryl stibines, all weight percentages based on the total weight of isocyanate mixture and polyhydroxy compounds are. Considered publications:
German publication No. 1112 285. 609 580/445 6.66 ® Bundesdruckerei Berlin