DE2344595C2 - Process for the production of rigid and semi-rigid polyurethane foams - Google Patents

Description

O — CH-CH ₂ ^ IOP ^CH 2— CH-O-

U I  Ί Ah ₁ C,

CH ₂ -CH-CH ₂

I I

OH OH

used where rin denotes a number between 2 and 6, x and ^ numbers z between n O and 12, the mean value χ + y per chain being between O and 12 and z (x -I- y), where ( x + ydtn means the mean value of χ + y 'in the entire molecule, is between 1 and 72, and Z is an aliphatic, saturated or unsaturated, optionally halogenated radical, where the halogen is chlorine or bromine, with 2 to 6 carbon atoms and the valence ζ represents

It is well known that rigid polyurethane foams find versatile and different technical applications, especially in the fields of construction and insulation, where fire resistance is a is a desired or even indispensable property.

Various means of imparting fire-resistant properties to polyurethane foams already exist. A known method consists in adding flame-retardant additives, such as antimony oxide or even to the foams Halogen and / or phosphorus compounds, e.g. B. tris (dibromopropyl) phosphate or tris (dichloropropyl) phosphate, chlorinated biphenyls and halogenated hydrocarbons to be added. These additions, which are attached to the Base polymers are not chemically bound, but can provide permanent, evenly distributed fire resistance not guarantee. In addition, they generally have a softening effect on the Foam, and as a consequence of this, they set the mechanical properties and, in particular, its compressive strength and its dimensional stability.

Another way of producing fire-retardant polyurethane foams is to use halogenated and / or to use phosphorus-containing polyols. In FR-PS 13 50 425 = GB-PS 10 05 657 is the use of halogenated Polyether polyols described, which by adding epihalohydrins to monomeric polyvalent Alcohols containing at least two hydroxyl groups can be prepared. This addition reaction produces halogenated polyether polyols, which have a number of secondary hydroxyl functions, which is equal to the number of hydroxyl functions of the monomeric polyhydric starting alcohol. From the reaction of organic polyisocyanates on these halogenated polyether polyols derived from cellular Polyurethanes have certain durable and satisfactory fire retardant properties, however their dimensional stability is generally insufficient. In addition, their manufacture is because of the poor reactivity of these polyether polyols difficult; this responsiveness is even less than

that of the corresponding non-halogenated polyether polyols.

From the aforementioned patents and GB-PS 9 60 009, the use of halogenated Polyäth η known as a polyol component, but these differ from those in the invention Process used halogenated polyether polyols in that they did not have any ff-diol groupings have, d. H. no primary and secondary, not due to the immediate vicinity of chlorine atoms have deactivated hydroxyl groups. From the comparative tests A and B it follows that these are known Although halogenated polyethers are capable of delivering non-flammable foams, they are a

50 have insufficient dimensional stability.

In contrast, the polyurethane foams produced by the process according to the invention have excellent dimensional stability in addition to the property of non-flammability.

The method according to the invention therefore relates to the production of rigid and semi-rigid polyurethane foams according to the patent claim.

The halogenated polyether polyols used in the process of the invention are in the German patent 23 23 702 by the applicant. Their preparation in Preparation Examples A and B explained in more detail.

The halogenated polyether polyols used according to the invention do not allow the production of combustible polyurethane foams which have similar or better mechanical properties than these

60 those made from commercially available, non-halogenated polyether polyols.

The halogenated polyether polyols can be used alone or in a mixture with non-halogenated polyether polyols can be applied. The relative proportion of halogenated polyether polyols in the used Mixture of the polyether polyols can vary quite widely. The self-extinguishing properties however, the higher this proportion, the better the polyurethane foams obtained. Rigid, self-redeeming Polyurethanes according to the ASTM-D-1692 standard can be made using mixtures of polyether polyols be obtained, which is a non-halogenated polyether polyol or more non-halogenated Polyether polyols and 40% by weight, preferably 70% by weight, of the least halogen-containing polyether polyols and contain only 20 to 35% by weight of the halogen-richest halogenated polyether polyols.

The rigid and semi-rigid polyurethane foams are in a known manner by reaction of the halogenated polyether polyols or mixtures of non-halogenated and halogenated polyether polyols with organic polyisocyanates in the presence of a blowing agent, one or more catalysts, optionally with the addition of water, emulsifiers and / or stabilizers, fillers or pigments, manufactured

The halogenated polyether polyols are used in the production of polyurethane foams according to all classic Appropriate procedures, e.g. B. the one-step process, the procedures that a prepolymer or use a semi-prepolymer, the pre-expansion process or so-called "whipped foaming".

All organic poly visocyanates commonly used for the production of rigid polyurethane foams are suitable Particularly preferred polyisocyanates are pure methylene bis (4-phenyl isocyanate) State or partially polymerized, tolylene diisocyanates in the pure state or in the form of the isomers Mixtures or 1,5-naphthalene diisocyanate.

The theoretically required amount of polyisocyanate to produce the polyurethane foams is in an known manner from the hydroxyl number of the polyether polyol or polyether polyols and optionally calculated based on the amount of water available. A slight excess of polyisocyanate is advantageously used, to ensure an isocyanate index of 105 to 120, reducing the thermal deformation of the resulting rigid polyurethane foam is improved.

The catalyst used can be any of the known catalysts used for this purpose be, especially tertiary amines such as triethylenediamine, triethylamine, trimethylamine and dimethylaminoethanol, and metal salts such as the salts of antimony, tin and iron. Triethylamine is one particularly preferred catalyst.

The amount of catalyst can vary to some extent; it affects the mechanical properties of the resulting foam. In general, 0.1 to 3% by weight of catalyst, based on the polyether polyol, is used or the mixture of polyether polyols.

The choice of propellant is not critical. The known propellants are all suitable without exception in particular water, halogenated hydrocarbons such as methylene chloride and chloroform and the chlorofluoroalkanes, z. B. trichloromonofluoromethane, dichlorodifluoromethane, and trichlorotrifluoroethane.

The amount of propellant can also vary quite widely. It is advantageous to use 0.1 to 10% by weight of water and / or 1 to 70% by weight of halogenated hydrocarbon, based on the polyether polyol or the mixture of polyether polyols.

The polyurethane foams are made by adding small amounts of a surfactant which contributes to the improvement of the cell structure; 0.2 to 2% by weight, based on the polyether polyol or the mixture of polyether polyols applied.

The halogenated polyether polyols used according to the invention are produced by hydrolysis of di- or polyglycidyl ethers of oligomers of epichlorohydrin of the following general formula in known way in a medium of dilute acid:

O-CH-CH ₂ -CH ₂ Cl

-CH ₂ -CH-O-

CH ₂ Cl _

-CH ₂ -CH-CH ₂
\ /
O

where ζ is a number between 2 and 6, χ and y are numbers between 0 and 12, the mean value χ + y per chain being between 0 and 12 and z (x + y), where (x + y is the mean value of χ + y \ m denotes the entire molecule, is between 1 and 72 and Z is an aliphatic, saturated or unsaturated, optionally halogenated radical, where the halogen is chlorine or bromine, with 2 to 6 carbon atoms with the valence ζ .

This hydrolysis can be accompanied by secondary condensation reactions, which lead to chain lengthening lead to the formation of chlorinated polyether polyols, which are richer in chlorine and less rich in hydroxyl groups are. It is not absolutely necessary to separate these products, which are also chlorinated Polyether polyols are that contain aliphatic diol groups. The presence of this affects the Synthesis of processed products not at all.

The hydrolysis of the di- and polyglycidyl ethers of oligomers of epichlorohydrin takes place advantageously in nitric or perchloric acid medium.

The amounts of water and acid to be used for the hydrolysis can vary widely. In particular, they determine the duration of the reaction as well as the extent of secondary reactions of the condensation. Advantageously used 1.2 x 10 ^"2 to 2.5 x 10 ^-2 moles of nitric acid and 1 to 10 kg of water per mole of di- or polyglycidyl ether.

The hydrolysis reaction takes place with stirring at the boiling point of the reaction mixture. The end of the reaction is determined by analyzing the residual oxirane oxygen. After cooling, the reaction product can be in the form of a two-phase system, the aqueous phase being the lightest polyether polyols contains, which are richest in hydroxyl groups, and the organic dense water-saturated phase the contains heaviest polyether polyols, which are the most halogen-rich. It is not absolutely necessary to separate these two phases and separate them to isolate the polyether polyols contained in them treat.

This procedure is "made to measure" for the production of halogenated polyether polyols, which is relative have variable contents of halogen and hydroxyl groups, which by the choice of the suitable Initial glycidyl ether and / or the hydrolysis conditions are determined, suitable.

The di- and polyglycidyl ethers of oligomers of epichlorohydrin are carried out in a manner known per se

40

Elimination of hydrogen chloride in an alkaline environment from chlorinated polyether polyols with terminal chlorohydrin residues obtained, which originate from the oligomerization of epichlorohydrin by aliphatic saturated or unsaturated, optionally chlorinated or brominated di- to hexafunctional polyhydroxy compounds was initiated with 2 to 6 carbon atoms.

A first type of di- and polyj; lycidyl ethers according to the general formula given above includes those compounds in which the radical Z in the formula is not halogenated. You will go through Elimination of hydrogen chloride from chlorinated polyether polyols obtained from catalytic oligomerization derived from epichlorohydrin, which by saturated or unsaturated aliphatic polyols, such as Ethylene, propylene and hexamethylene glycols, glycerine, butane and hexane trio, trimethyl propane, erythritol and pentaerythritol, mannitol and sorbitol, di- and triethylene glycol, dipropylene glycol, 2-butene-1,4-diol, 3-butene-1,2-rHol, 2-butyne-l, 4-diol, 3-butyne-l, 2-diol, l, 5-hexadiene-3,4-diol, 2,4-hexadiene-l, 6-diol, l, 5-hexadiene 3,4-diol and 2,4-hexadiyne-1,6-diol was initiated.

Particularly preferred polyols are 2-butene-1,4-diol, 2-butyne-1,4-diol, ethylene glycol and glycerine.

A second type of di- and polyglycidyl ethers, which lead to polyether polyols with an increased halogen content are those in which the radical Z in the general formula given above is halogenated, wherein the halogen is chlorine or bromine. You can by splitting off hydrogen chloride from chlorinated polyether polyols obtained from the catalytic oligomerization of epichlorohydrin, the through saturated or unsaturated, halogenated polyols such as monochlorohydrins and monobromohydrins of glycerine, 3,4-dibromo-1,2-butanediol, 2,3-dibromo-1,4-butanediol, 2,3-dibromo-2-butene-1,4-diols, 3,4-dibromo-2-butene l, 2-diols, 2,2-dibromomethyl-1,3-propai.diol and 1,2,5,6-tetrabromo-3,4-hexanediol was initiated.

The oligomerization of epichlorohydrin can also be carried out by a mixture of brominated and / or unsaturated Diols are initiated.

The molar ratio of epichlorohydrin and polyol initiator is not critical and can vary within large amounts. This ratio determines the hydroxyl number of the resulting polyether polyol.
The oligomerization catalyst can be any of the known acidic catalysts for this type of reaction. However, preference is given to using boron trifluoride in the free or complexed state.

Di- and polyglycidyl ethers of brominated oligomers of epichlorohydrin can also be partially or total molecular bromination of di- or polyglycidyl ethers of unsaturated oligomers of epichlorohydrin obtained, which by splitting off hydrogen chloride in an alkaline medium from unsaturated chlorinated Polyether polyols were obtained which were initiated from the catalytic oligomerization of epichlorohydrin by an unsaturated di- or polyhydroxyl compound.

In addition, the halogen content of the polyether polyols can be increased and thereby the Flame resistance of the polyurethanes derived from them are increased if these polyether polyols are still used Have unsaturations in that a partial or total bromination of these unsaturations takes place. After this Technique of work one brominates the unsaturated Polyoie, which from the hydrolysis in a medium diluted Acid of di- or polyglycidyl ethers of unsaturated oligomers of epichlorohydrin of the following general Formula originate from:

-O-f CH ₂ -CH-O ^ f-CH ₂ -CH-CH ₂

ι ¹ TiTv

L CH ₂ Cl J., ·

where λ, j and z are as defined above and Y is an unsaturated aliphatic Resi nit 2 to 6 carbon atoms with the valence ζ represents.

The type of bromination of polyether polyols and glycidyl ethers is not critical. It is possible to work in a manner known per se, if appropriate in the presence of a catalyst and an inert solvent, such as chloroform, carbon tetrachloride, methylene chloride or o-dichlorobenzene.
The temperature is maintained generally below 50 to 60 ⁰ C.

The amount of bromine used is not critical. However, preference is given to using bromine in a stoichiometric amount Lot. The particularly preferred polyether polyols correspond to the general formula in which Z is one of the represents the following residues:

CH ₂ Cl-CH- -CH ₂ -CHBr-CHBr-CH ₂ -CH ₂ -

-CH ₂ -CBr = CBr-CH ₂ -

The invention is explained in more detail with reference to the following examples, the production of the invention Polyether polyols used in Production Example A for chlorinated polyether polyols and in Production Example B is described for a chlorobrominated polyether polyol.

Example 1 relates to a polyurethane foam, which with the help of a chlorinated polyether polyol has been produced according to production example A, example 2 the production of a foam using a chlorobrominated polyether polyol according to preparation example B and example 3 Such polyurethane foams, which with the help of a mixture of chlorobrominated polyether polyols according to ProductionAbeispitM B and a commercially available non-halogenated polyether polyol has been produced.

1.337 25th ■ ' 750 25th 409 9 30th 534 1.51 '■ !

This commercially available non-halogenated polyether polyol had a hydroxyl number of 503 and a viscosity at 20 ^° C. of 118 P.

The comparative tests A and B show PolyurethanschaumstofTe which are commercially available with the help of the mentioned Polyatherpolyol or with the aid of one chlorinated according to FR-PS 13 50 425 and by oligomerization of epichlorohydrin in the presence of glycerine in a molar ratio of 4/1 synthesized polyatherpolyol 5, have been manufactured.

Preparation example A

In a 2-1 glass reaction vessel that is immersed in a thermostatically controlled oil bath and equipped with a stirrer and was equipped with a reflux condenser, 500 g, i.e. H. approx. 1 mole, diglycidyl ether of the tetramer of epichlorohydrin, 1000 ml of demineralized water and 12.5 ml of η-nitric acid introduced, ί

The mixture is brought to the boil and stirred continuously. After 20 hours, the analysis of the oxirane;, '■'

Oxygen indicates that all of the diglycidyl ether is hydrated. The reaction mixture is then cooled -15 s; and as it is, without separation of the aqueous and organic phases, evaporation with reduced ί

system subjected to pressure, so that the greater part of the water is driven off. The chlorinated polyether polyols are then dried by azeotropic distillation of the water using methylene chloride. £;

A take-away by nitrogen at 60 ⁰ C allows the expulsion of the last traces of water and ^methylene; .

lene chloride. A clear, relatively viscous liquid is obtained with the following properties:

specific weight, 20 ^° C. viscosity at 20 ^° C., P chlorine content,% by weight hydroxyl number

Gardner discoloration index mean molecular weight measured mean of (x + y) calculated

Production example B

In a 2-1 glass reaction vessel immersed in a thermoslated oil bath and equipped with a stirrer and If equipped with a reflux condenser, 500 g, i.e. 1.16 mol, of the diglycidyl ether are obtained at ambient temperature of an unsaturated oligomer of epichlorohydrin, which by splitting off hydrogen chloride from the: ..-.

Product had been prepared which came from the addition of 4.5 mol of epichlorohydrin to 1 mol of butynediol, 3.-. 1000 ml of demineralized water and 2.9 ml of an aqueous 70% strength by weight perchloric acid solution were added. Γ

The procedure of Preparation Example A is then repeated. It becomes agile, brownish Liquid obtained which contains 1.16 moles of chlorinated polyether polyol, which has an acetylene-like unsaturation has, correspond.

1.16 mol of bromine are added dropwise to the cooled reaction mixture, to which 1.4 g of boron trifluoride diethyl etherate have been added. It is ensured that the temperature does not exceed 5O ⁰ C. After the introduction of the bromine, which takes about two hours, the mixture is stirred further until the brown vapors of the gas phase have disappeared. The acid content is then neutralized by adding anhydrous calcium carbonate and held for two hours with vigorous stirring. A release of carbon dioxide is observed. To the rather viscous mass obtained, 0.5 l of methylene chloride are added and then filtered in order to separate off the calcium carbonate. The methylene chloride is then removed by evaporation at 95 ° C. under 15 mm of mercury to constant weight.

The properties of the obtained, chlorobrominated polyatherpolyol, which contains a double bond, are the following:

specific weight, 20 ^° C. 1.67

Viscosity at 20 ^° C. P 900

Chlorine content, wt% 14.2

Bromine content, wt% 25.6

Hydroxyl number 330 55 M.

Gardner discoloration index 10 ρ

average molecule weight ularge measured 746 p

Mean of (x + y), computed 1.9 f |

Example 1 60 y§

100 g of the chlorinated polyether polyol of Preparation Example A, 04 g of silicone oil, 2 g of triethylamine and 40 g of trichlorofluoromethane are introduced successively into a 400 ml glass vessel. The mixture is stirred so that it becomes completely homogeneous. 103.8 g of crude methylene bis (4-phenyl isocyanate) are then added. The resulting mixture is stirred for 20 seconds, then poured into a mold and allowed to harden at ambient temperature. The creaming time is 3 seconds, the rise time is 30 seconds. A rigid, self-extinguishing foam is obtained whose physical and mechanical properties are shown in Table I and whose fire-resistant properties are shown in Table Π.

Example 2

The procedure of Example 1 is repeated, except that 100 g of the chlorobrominated polyether polyol are used

of Preparation Example B and 109.2 g of crude methylene bis (4-phenyl isocyanate) are used. The up

5 cream time is 6 seconds and the rise time 24 seconds. You get a rigid, self-extinguishing one Foam, the physical and mechanical properties of which can be found in Table I and its refractory properties

Properties are shown in Table II.

Example 3

The procedure of Example 1 is repeated, except that 50 g of a mixture of the chlorobrominated polyether polyol from Preparation Example B, 50 g of the commercially available polyether polyol, 1.5 g of triethylamine and 106 g of methylene bis (4-phenyl isocyanate) are used. In this way, a rigid, self-extinguishing foam is obtained with a creaming time of 13 seconds and a rise time of 75 seconds.
15 The physical and mechanical properties of this foam can be seen from Table I and its fire-resistant properties from Table II.

Comparative experiment A

The procedure of Example 1 is repeated, except that 100 g of the commercially available polyether polyol are used 128 g of methylene bis (4-phenyl isocyanate) and a mixture of amines, which 1.5 g of triethylamine and 0.5 g Contains triethylenediamine, can be used. In this way a rigid, flammable foam is obtained a creaming time of 35 seconds and a rise time of 85 seconds. The physical and mechanical Properties of this foam are shown in Table I, its fire-resistant properties from Table II.

Table I.

Example or comparative experiment 1 2 3

Properties of the foam

apparent specific gravity, kg / m ³ 36.3 36 32 29.6

Average cell dimensions, mm horizontally in the vertical direction

Proportion of closed cells (Scholten method),% *)

Water absorption (ASTM D 2127 standard),% by volume

Specific thermal conductivity (standard DIN 5 2612), cal / cm · see · ⁰ C

Compressive strength (ISO R 844 standard), kg / cm ² **)

Stress at 10% deformation maximum load

Flexural strength (standard ISO R 1209) **)

Tear load, kg Knife movement when peeing, mm

Dimensional stability at 100 ° C and ambient humidity ICI aluminum foil method, specimen 15 x 15 X 1 cm, surface change,%

after 1 day +5.8 0 n.a. +4.7

60 after 7 days +8.6 0 +4.5 +8.3

according to the Scholten method, test specimens 5x5x5 cm, change in the mean Length of the flapping fin,%

65 after 1 day +0.53 n.a. n. g. +0.87

after 7 days +1.1 '+0.5 n.a. +1.5

0.24
0.42 ΙΟ " ⁴ 0.22
0.46 ΙΟ " ⁴ 0.32
0.46 -HT ⁴ 0.30
0.65 ΙΟ " ⁴ 90 4 * 91 4th 91 4 * 88 4 * 1.8 1.35
1.35 1.8 1.34
ng 2.5 ng
ng 1.5 1.16
1.16 0.7 X * 0.6 ■ 0.63 0.6 4 * TT 2.66
12.0 TT TT TT 2.71
10.0 1.64
1.91 1.93
ng 2.37
ng 1.88
1.88 TT TT 1.56
18.1 ng
ng ng
ng 1.49
14.4

continuation

Example or comparison test
1 2 3

Friability (ASTM C 421 standard) Weight loss,%

after 2 minutes

after 10 minutes

4.0
16.8

2.0
11.2

0.7
5.2

n. g.

") Π

Table II

not measured

does not include correction for surface cells

Signs for stresses parallel to the expansion of the foam

Sign for stresses perpendicular to the expansion of the foam

Example or comparative experiment
2 3

4.2
26.0

Flammability test (ASTM-D-1692 standard)

Great

line elapsed before going out, s burning time, s

Burn Extent, cm Burn Extent,% Burn Rate, cm / min

Flammability test (ASTM-E-162 standard)

Great

time elapsed before going out, s burning time, s

Burn Extent, cm Burn Extent,% Burn Rate, cm / min

s. e. s. e. s. e. flammable 47 43 47 - - - - 46 2.6 3.3 3 12.7 20.5 25.9 23.5 100 3.3 4.6 3.8 16.6 s. e. s. e. s. e. flammable 132 n. g. 86 - - n. g. - - 17.6 n. g. 31.5 - 61.5 n. g. 90 - 9.8 n. g. 22nd -

ng
se

not measured self-extinguishing

Comparative experiment B

The procedure of Example 1 is repeated, except that 100 g of an oligomer of epichlorrydrin are used can be used, which were prepared by adding 5 moles of epichlorohydrin to 1 mole of glycerol. The main characteristics of this product are as follows:

specific weight, 2O ⁰ C viscosity at 20 ⁰ C, P chlorine content wt .-% hydroxyl number

Gardner Discoloration Index, mean molecular weight, measured

1.347
232
32.41
282

3
548

In addition to the 100 g of the oligomer, 0.5 g of silicone oil, 1.5 g of triethylamine, 30 g of trichlorofluoromethane and 71.6 g of crude methylene bis (4-phenyl isocyanate) were used.

The creaming time increases to 20 seconds. After 101 seconds, a foam has developed with a specific weight of 35.8 kg / m ³ , which is self-extinguishing in accordance with the ASTM-D-1692 and E-162 standards

The flexural strength and compressive strength properties of this foam are comparable to those of the foam produced according to Example Γ. However, its dimensional stability is completely insufficient; the changes in the surface or the mean length of the flippers of test specimens of 15 × 15 × 1 cm, which were kept for one day at 100 ^° C. under ambient humidity, are not at all measurable because of the softening of the test specimens and the occurrence of numerous cracks.

The comparison of properties of rigid, according to Examples 1, 2 and 3 and the comparison tests A and B produced polyurethane foams clearly shows that by using the inventively used halogenated polyether polyols, the production of rigid, self-extinguishing foams is possible is, which have mechanical properties that make those more rigid, with the help of non-halogenated Polyether polyols produced foams are comparable or even superior, and in particular one have good dimensional stability, a property which is essential to the effective use of rigid foams and uie do not have foams made using known chlorinated polyether polyols.

Claims (1)

Claim: Process for the production of rigid and semi-rigid polyurethane foams by the implementation of a organic polyisocyanate with a halogenated polyether polyol, optionally mixed with not halogenated polyether polyols, in the presence of a catalyst, a blowing agent and a surfactant Mitt ilSjdifferent that one such as halogenated polyether polyol the general formula