DE1769024C3 - Process for the production of flame-resistant polyurethane foams - Google Patents

Description

The patent 16 94 430 relates to a process for the production of flame-resistant polyurethane foams by reacting an organic polyisocyanate with a glycol having a molecular weight of at least 250 in the presence of a friction agent, a Trishalogenalkylphosphats as Flame retardants, and optionally other additives, the novelty of the invention consists in that in the implementation of a previously prepared mixture containing a basic reacting substance Polyol and trischloropropyl phosphate is used.

In the process of the main patent, the organic polyisocyanate is usually used in an amount uses that 4 to 6.7 and occasionally up to 10 isocyanate group equivalents for each equivalent active hydrogen are present. In these systems the proportion of polyol is in the total Foaming reaction mix much less than in typical polyurethane foam batches, and around It is important to make foams that contain an effective concentration of flame retardant expedient to use premixes that have a higher proportion of trischloropropyl phosphate in the ratio to polyol than the premixes used in normal polyurethane foam production.

The invention now relates to a further development of the subject matter of the main patent, than for the mixture of the polyol and trischloropropyl phosphate containing a basic substance a solid mixture is used, which consists of 100 parts by weight of at least one polyol and 60 to 300 parts by weight of a trischloropropyl phosphate consists.

Processes for the preparation of trischloropropyl phosphate are well known. An example of this is the Implementation of propylene oxide with phosphorus oxychloride in the presence of various catalysts, such as. B. the Halides of titanium and zirconium. The product obtained by these methods is usually a Mixture of isomers, which in particular is tris-2-chloropropyl phosphate, tris-2-chloroisopropyl phosphate and contains phosphoric acid esters in which the 2-chloropropyl and 2-chloroisopropyl radicals are both in one Connection are present. These mixtures are particularly suitable for processing according to the invention suitable.

Polyols that can be used in the process of the invention are, for. B. monomers Polyols such as B. ethylene glycol, propylene glycol, tetramethylene glycol, Diethylene glycol, glycerine or triethanolamine, or polyols with a higher molecular weight, such as B. polyether or polyester polyols.

Suitable polyether polyols can have been prepared by reacting one or more alkylene oxides with a compound which contains several active hydrogen atoms. Suitable alkylene oxides are, for. B. ethylene oxide, epichlorohydrin, 1,2-propylene oxide, 1,2-butylene oxide or 2,3-butylene oxide. Mixtures of two or more oxides may optionally have been used. As a further variant, the compound containing the active hydrogen can have been reacted with two or more alkylene oxides in successive stages, for example propylene oxide having been used in the first stage and ethylene oxide in the second stage. Compounds containing several active hydrogen atoms with which the alkylene oxides may have been reacted are, for. B.

Water, ammonia, hydrazine, cyanuric acid,
Polyhydroxy compounds, for example
Ethylene glycol, propylene glycol,
Diethylene glycol, glycerin.
Trimethylolpropane, triethanolamine,
Pentaerythritol, sorbitol. Sucrose,
Phenol / formaldehyde reaction products,
Resorcinol or phloroglucinol,
Amino alcohols, for example
Monoethanolamine or diethanolamine,
Polyamines, for example
Ethylenediamine, hexamethylenediamine,
Tolylendia.min or diaminodiphenylmethane,
as well as polycarboxylic acids, for example
Adipic acid, terephthalic acid or
Trimesic acid.

The conditions for the reactions between the alkylene oxide and the active hydrogen containing Compounds can be of the type described in the literature, with, for example, basic Catalysts, for example potassium hydroxide, or acidic catalysts, for example boron trifluoride, are used have been. The reaction products have molecular weights of 150 to 5000 corresponding to Amount of alkylene oxide reacted with the active hydrogen containing compound.

Suitable polyester polyols can be made, for example, from dicarboxylic acids and polyhydric alcohols have been made. Suitable dicarboxylic acids are, for. B. succinic acid, glutaric acid, adipic acid, suberic acid, Azelaic acid or sebacic acid, as well as aromatic acids, such as. B. phthalic acid, isophthalic acid or terephthalic acid. Mixtures of acids can also be used. Examples of multivalued Alcohols are glycols, for example

Ethylene glycol, diethylene glycol,
Tetramethylene glycol, pentamethylene glycol,
Hexamethylene glycol, decamethylene glycol or
2,2-dimethyltrimethylene glycol.

Mixtures of glycols can be used being. Other polyhydric alcohols, such as. B. trimethylolpropane, pentaerythritol or glycerol can be used in

various amounts incorporated or used alone, as desired Properties of the products. The polyesters may contain amide groups which have been introduced thereby are that some amount of a diamine or an amino alcohol is included in the polyester formation reaction mixture have been introduced. Suitable diamines or amino alcohols are, for. B. ethylenediamine, hexamethylenediamine, Tolylenediamine or ethanolamine.

Polyesterification products with hydroxyl numbers in the range from 200 to 700 and not more than 1.5 branch points for every 1000 molecular weight units. These polyesterification products The isocyanurate groups are particularly suitable for the production of rigid polymer foams have and excellent high temperature properties, such as. B. Flame Resistance, in Connect with minimal brittleness. The polyesterification products can by reaction of aliphatic diols, such as. B. the glycols listed above, with aliphatic dicarboxylic acids, and optionally with smaller amounts of aromatic dicarboxylic acids, and if desired, sufficient Polyol or polycarboxylic acid with a functionality greater than two to achieve the necessary degree of branching to achieve, have been established. At the lower end of the hydroxyl number are the polyesterification products Polyesters with molecular weights of up to 1000. At the upper end of the hydroxyl number are the polyesterification products mainly mixtures of a low molecular weight polyester, such as. B. Diester, and off variable amounts of unesterified monomeric! Polyol.

Mixtures of polyols can also be used.

The superior stability of the approaches compared to the corresponding approaches, the tris-2-chloroethyl phosphate instead of Trischlorpropj! Phosphat, is due to the presence of the basic reacting Particularly pronounced. The basic reacting substance can be an impurity, for example the Remainder of an alkaline catalyst, which in the reaction between an alkylene oxide and a active hydrogen-containing compound has been used. On the other hand, it can be basic reactant be an intentionally added component, such as. B. a catalyst for polymerization of isocyanates.

Basic catalysts for the polymerization of isocyanates are generally known. Examples of this are strong bases, such as B. quaternary ammonium hydroxides, for example benzyltrimethylammonium hydroxide, Alkali metal hydroxides, for example potassium hydroxide, or alkali metal alcoholates, for example sodium alcoholate. Other suitable catalysts are e.g. B. Substances with a weaker basic nature, such as z. B. alkali metal salts of carboxylic acids, such as sodium acetate, potassium acetate, potassium 2-ethylhexoate, Potassium adipate or sodium benzoate, certain tertiary amines, for example N-alkylethyleneimines, N- (2-dimethylaminoethyl) -N'-methylpiperaziane or tris-3-dimethylaminopropylhexahydro-s-triazine.

The polymerization catalysts can be used in amounts of 1 to 50 parts by weight for every 100 parts by weight Polyol be present.

Other basic reacting materials that may be present are e.g. B. tertiary amines used for Used to catalvse the reaction between the polyol and the polyisocyanate during foam formation will.

Suitable tertiary amines are, for. B. in particular those species that are already used for the catalysis of Polyurethane reactions were used. It should be mentioned:

Triethylamine, dimethylethylamine,
Dimethylbenzylamine, dimethylcyclohexylamine,
Dimethylphenylethylamine,
Tetramethyl-1,3-butanediamine,
Diazabicyclo [2,2,2] octane,
N-alkylmorpholino, N-alkylpyrrolidines,
N-alkylpiperidines, pyrrolizidine,
jS-dimethylaminopropionamide,
1,1'-dimethyl-4,4'-bipiperidyl or
fully N-substituted 4-aminopyridines,
such as B. 4-DimetPylaminopyridine.

Particular mention should also be made of those tertiary amines which are reactive with isocyanates and which have been given as crosslinking agents for polyurethane systems, for example

N-methyl diethanolamine, triethanolamine,
Triisopropanolamine,

Tetrakis-2-hydroxyethylethylenediamine or
Tetrkis 2-hydroxypropylethylenediamine.

The tertiary amines can be present in amounts up to 50 parts by weight for every 100 parts by weight of polyol.

In some cases the polyol itself may contain one or more tertiary amino groups, for example it can be a reaction product of propylene oxide with triethanolamine or tolylenediamine.

In the inventive method, other conventional foaming additives can be used, for example Inalogenierte hydrocarbons having boiling points not exceeding 100 ⁰ C, and preferably -40 to 50 ⁰ C, at atmospheric pressure. Such compounds are often used as blowing agents in foam lattices. Examples of such halogenated hydrocarbons are:

Methylene chloride, vinylidene chloride or

especially fluorinated hydrocarbons,

such as B. trichlorofluoromethane,

Dichlorodifluoromethane, dichlorofluoromethane,

Monochlorodifluoromethane,

Dichlorotetrafluoroethane,

1,1,2-trichloro-i, 2,2-trifluoroethane,

Dibromodifluoromethane or

Monobromo trifluoroethane.

Such agents can be present in amounts of up to 1000 parts by weight for every 100 parts by weight of polyol being.

Other foaming additives that may optionally be present are e.g. B. water, silicone fluids, such as B. Siloxari / oxyalkylene copolymers, colorants, plasticizers, fillers and antioxidants.

The superior storage stability compared to similar approaches containing tris-2-chloroethyl phosphate, can be demonstrated in a variety of ways. In some cases the effect can be seen visually, if crystals in the the tris-2-chloroethyl phosphate

containing approaches are deposited at a much greater rate than in the trischloropropyl phosphate approaches. Differences between these approaches can also come to light in the foaming reaction and in the properties of the foams obtained, because the tris-2-chloroethylphosphate approaches react slowly after aging. For the purpose of comparison, the differences can be shown quite simply by determining the ionizable chlorine content of the batches. The ionizable chlorine content of the tris-2-chloroethylphosphate salts increases with storage at a much greater rate than in the present case.

As already mentioned, the invention is particularly suitable for the production of hard polymer foams by reaction with organic polyisocyanates, such as. B. pure or crude tolylene diisocyanates or diphenylmethane diisocyanates. Crude diphenylmethane diisocyanate mixtures are particularly preferred, which contain 5 to 70% by weight of polyisocyanates with a functionality greater than two and which by phosgenation of crude aniline / formaldehyde conversion products have been manufactured.

Particularly useful approaches for the reaction with polyisocyanates in the presence of a blowing agent contain 100 parts by weight of one or more polyols, 60 to 200 parts by weight of trischloropropyl phosphate, 2 to 20 Parts by weight of catalyst, such as. B. potassium acetate, 0.25 to 10 parts by weight of a tertiary amine, such as. B. Diazabi- 3c cyclo- [2,2,2] octane, and 0 to 20 parts by weight of a siloxane-oxyalkylene copolymer.

The invention is illustrated in more detail by the following examples. All parts and percentages are in Expressed weight.

The stability of the mixture is monitored by determining the ionized chlorine content, the the following results can be obtained:

% ionizable
chlorine

In the preparation of
After 5 weeks at 2O ⁰ C.
After 5 weeks at 40 ^° C

less than 0.01
less than 0.01
0.04

When the above approach (27.6 parts) with 100 parts of a crude diphenylmethane diisocyanate mixture and is mixed with 20 parts of trichlorofluoromethane, then a rigid polyurethane foam is formed.

Example 2 A mixture is made as follows:

Diethylene glycol / adipic acid poly

esterification product as in

example 1

Ethylene glycol

Potassium acetate

Siloxane polyoxyalkylene

Mixed polymer

Diazabicyclo [2.2.2] octane

Trisloropropyl phosphate

The stability of the mixture is monitored by determining the ionizable chlorine content, the the following results can be obtained:

% ionizable chlorine

In the preparation of
After 5 weeks at 20 ^° C
After 5 weeks at 40 ° C

less than 0.01

0.02

0.1

When the above mixture (26.8 parts) with 100 parts of a crude diphenylmethane diisocyanate mixture and is mixed with 20 parts of trichlorofluoromethane then a rigid polymethane foam is formed.

Example 3

Mixtures useful for making rigid polyurethane foams will be like is made as follows:

example 1

Diethylene glycol / adipic acid polyesterification product with a
Hydroxyl value of 500 mg KOH / g and
an acid value of 1 mg KOH / g 13

Ethylene glycol 1

Potassium acetate 1

Water 0.01

Siloxane-polyoxyalkylene copolymer 2

Ν, Ν-dimethylcyclohexylamine 0.5

Trisloropropyl phosphate 10

1,4-butanediol 10

Potassium 2-ethylhexoate 2

Octylphenol ethylene oxide condensate 2 trischloropropyl phosphate or

Tris-2-chloroethyl phosphate 15

The stabilities of these blends are compared by heating to 8O ⁰ C and then determining the ionizable chlorine content.

% ionizable chlorine trischlor- tris-2-chlorine-

propyl phosphate ethyl phosphate

At first
To

hours
Days

<0.01

0.17
0.44

Example 4

<0.01

1.03> 2

Mixtures that are suitable for the production of rigid polyurethane foams are like is made as follows:

Propylene glycol / glycerin / adipic acid polyesterification product with a Hydroxyl value of 340 mg KOH / g and an acid value of 2.2 mg KOH / g 23

Diazabicyclo [2.2.2] octane 0.1

Trischloropropyl phosphate or
Tris-2-chloroethylphosphiii 15

The stabilities of the mixtures are ^{compared by heating to 80 °} C. and then determining the ionizable chlorine content:

% ionizable chlorine trischlor- tris-2-chlorine-

propyl phosphate ethyl phosphate

At first

24 hours

<0.01 <0.01

0.08 0.11

Example 5

Mixtures are produced which have the compositions given in the following table:

1,4-butanediol 67 67 67 67

Potassium acetate 6.7 6.7 6.7 6.7

N.N-dimethyllcyclo- 10 10 10 10

hexylamine

Siloxane-oxyalkylene- 20 20 20 20

Mixed polymer

Water - 2 - 2

Tris-2-chloroethyl 100 100 - -

phosphate

Trischloropropyiphosphate - - 100 100

The mixtures are stored at room temperature and the ionizable chlorine levels are in the Sequence specified intervals determined

% ionizable chlorine

Initially 2 weeks 4 weeks 6 weeks 8 weeks

40

A 0.013 0.18 0.32

B 0.014 0.23 0.34

C 0.013 0.018 0.026

D 0.013 0.033 0.031

0.49

0.60

0.039 0.035

0.034 0.035

45

The mixtures were reacted with a crude diphenylmethane diisocyanate mixture to produce rigid foams. The stored mixtures containing trischloropropyl phosphate were markedly superior in their foaming behavior to the corresponding mixtures containing trischloroethyl phosphate.

Example 6

Mixtures are prepared which are those in the following Have compositions given in the table.

ss

Oxypropylated trimethylol 58 58 propane (hydroxyl value 2.9 2.9 540mgKOH / g) 4th 4th Potassium acetate Ν, Ν-dimethylcyclohexylamine 12th 12th Siloxane oxyalkylene 100 100 Mixed polymer 40 - Trichlorofluoromethane - 40 Tris-2-chloroethyl phosphate Trischloropropyiphosphate

20 The blends are stored at room temperature and the ionizable chlorine content is determined in the following table specified in dei intervals.

% Ionizable chlorine

Initially 2 weeks 4 weeks 6 weeks 8 weeks

0.011
0.014

0.048
0.036

0.068
0.035

0.11
0.034

0.155
0.056

The mixtures are reacted with a crude Diphenylme thandiisocyanate mixture to produce hard foam to manufacture fabrics.

Example 7

Mixtures are produced which have the compositions given in the table below.

1,4-butanediol 66.5 66.5

Potassium 2-ethylhexoate 12.4 12.4

Ν, Ν-dimethylcyclohexylamine IO 10

Ethylene oxide / propylene oxide mixed polymer (commercially

as »Pluronic« L61) 45 45

Water 1.2 1.2

Tris-2-chloroethyl phosphate 100 -

Trischloropropyiphosphate - 100

The mixtures are stored at room temperature and the ionizable chlorine levels are determined according to the in intervals specified in the following table.

% ionizable chlorine
Initially 2 weeks

4 weeks 6 weeks

A 0.008 B 0.016

0.19 0.017

0.265 0.022

0.035

The mixtures are reacted with a crude diphenylmethane diisocyanate mixture to produce hard foams. The stored mixtures containing tris-2-chloroethyl phosphate show a noticeable Deterioration of the foaming behavior,

70S 627/89

Claims (1)

Claim: Process for the production of flame-resistant polyurethane foams according to patent 16 94 430 by reacting an organic polyisocyanate with a glycol having a molecular weight of at least 250 in the presence of a blowing agent, a trishaloalkyl phosphate as a flame retardant, and optionally other additives, with the implementation of a previously prepared mixture of polyol and trischloropropyl phosphate containing a basic substance is used, characterized in that such a mixture is used that consists of at least 100 parts by weight of a polyol and from 60 to 300 parts by weight of a trischloropropyl phosphate.