DE2356869A1 - Process for the production of non-flammable, rigid polyurethane foams - Google Patents

Description

PATENT LAWYERS

DR. ING. A.VAN DERWERTH DR. FRANZ LEDERER

21 "HAMBURG 90 8 MÖNCHEN 80

WlLSTORFERSTR 32 TEL. (O 401 77 08 61 LUCILE-CRAHN-STR. 22 '■ TEL. (08 1 11 47 39 47

Munich, October 19, 1973 pp 72/31

'· SOLVAY & CIE.
33, rue du Prince Albert, Brussels, Belgium

Process for the production of non-combustible, rigid polyurethane foams

The invention relates to a process for the production of rigid polyurethane foams and, in particular, of rigid, non-combustible ones Polyurethane foams, which are dimensionally stable.

It is known per se that rigid polyurethane foams are very different Sales opportunities of growing importance in industry and in particular in the fields of construction, des Aircraft and shipbuilding, especially for heat insulation, Find. In these areas there is a growing need for refractory d. H. incombustible materials. ,

There are already several means of imparting fire-resistant properties to polyurethane foams. One known method of operation ... consists in adding non-combustible additives such as antimony oxide to the foams

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TELEGRAM MC: L B t> CRERPATCN T MONKS

or halogen and / or phosphorus compounds, such as Tris (dibromopropyl) phosphate or tris (dichloropropyl) phosphate, chlorinated diphenyls and halogenated hydrocarbons. These additives, which are not chemically bound to the base polymer, are, however, not able to provide a permanent, ensure uniformly distributed fire resistance. In addition, they generally have a plasticizing effect on the foam and as a result deteriorate its mechanical properties, in particular its compressive strength and its dimensional stability.

Another means of making fire retardant polyurethane foams consists in using halogen polyols and / or phosphor polyols.

In the French patent 1 550 425 is the use of chlorinated polyether polyols described which by Oligomers of epichlorohydrin are formed by the addition of epichlorohydrin to monomeric, at least two hydroxyl radicals containing polyhydric alcohols were produced. The resulting from the reaction of organic polyisocyanates with these chlorinated, Cellular polyurethanes derived from polyether polyols Although they have permanent and satisfactory, fire-resistant properties, they are also in accordance with the ASTIl D 1692 and E standard self-extinguishing, but its dimensional stability is not sufficient. Deform under the influence of temperature changes build such barns, and their mechanical properties quickly.

It now became a simple, powerful, and cheap one Process for the production of non-flammable, rigid polyurethane foams with the aid of chlorinated polyether polyols found according to the prior art, these foams being dimensionally stable, d. H. are dimensionally stable.

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The method according to the invention "therefore relates to production of non-flammable, rigid polyurethane foams by reacting an organic polyisocyanate with at least one chlorinated one Polyether-polyol, which results from the addition of epichlorohydrin to a monomeric, at least three hydroxyl radicals per molecule containing polyol, in the presence of a conventional catalyst and a conventional blowing agent, the The process is characterized in that the reaction is carried out in the presence of boron trifluoride in free or complex-bound form State performs.

Surprisingly, it was found that the presence of boron trifluoride in the mixture based on chlorinated, by oligomerization of epichlorohydrin in the presence polyether polyols obtained from a polyhydric alcohol, which is used for the production of the polyurethane foams, in a noticeable improvement in the dimensional stability of the manufactured, rigid, non-flammable polyurethane foams.

It was completely surprising that boron trifluoride and only this Connection alone has the option of rigid polyurethane foams based on epichlorohydrin oligomers, dimensionally stable close. Other aprotic acids like SnCl ^, AlCl ,, FeCl. ,, ZnCIp, TiCl ^ and AlBr ^ have this surprising property not on.

The improvement effect observed is beyond that attributed to chlorinated polyether polyols. So improved the addition of boron trifluoride to epibromohydrin oligomers in in no way the dimensional stability of the resulting brominated Polyurethane foams. ■

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The improvement in the dimensional stability of the invention produced, rigid polyurethane foams does not depend on the exact point in time at which the addition of boron trifluoride to the chlorinated polyether-polyol takes place. This can be done before or during the foaming reaction. Yet it is essential that a mixture is present which already contains the chlorinated polyether-polyol to which one is added adding the boron trifluoride. The prior addition of boron trifluoride to the organic polyisocyanate is without the slightest Influence on the dimensional stability of the resulting foams.

Since boron trifluoride is a gas at ordinary temperature, it is advantageously in the form of a derivative or a Complex used, which is liquid at ambient temperature. Preferred compounds are the ether complexes of boron trifluoride, like the complexes with lower ethers and especially diethyl ether. .

The amount of boron trifluoride is not critical and can vary over a wide range of ratios. Smallest amounts of Boron trifluoride on the order of tens of ppm (parts per million in weight), based on the chlorinated polyether polyol, already contribute to an improvement in the dimensional stability of the rigid, non-combustible foams according to the invention at. ·.

However, such contents are not sufficient to guarantee the production of foams that are technically usable Have dimensional stability.

If you use boron trifluoride in an amount of a few 0.0J wt .-%, based on the chlorinated polyether-polyol used, one already obtains foams with dimensional stability in the same Of the order of magnitude, such as those foams based on non-halogenated, commercially available polyether polyols.

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The dimensional stability of the polyurethane foams according to the invention can still be achieved by adding larger amounts of boron trifluoride something to be improved. However, it is useless to use boron trifluoride levels on the order of 6% by weight, based on the halogenated polyether-polyol, to exceed.

It is advantageous to use from 0.03 to 6% by weight and preferably 0.045 "to 3 wt .-% boron trifluoride, based on chlorinated Polyäthef-Polyol.

The chlorinated polyether-glycols which can be used in the process according to the invention are processed in a manner known per se Addition of epichlorohydrin to one or more, monomeric, polyols having at least three hydroxyl radicals in the presence of an acidic catalyst.

The monomeric polyols. Which are used to initiate the oligomerization of epichlorohydrin for the production of the according to the invention Process applicable polyether-polyols are, for. B. TrioIe such as glycerine, butane and hexanetriol, Trimethylolpropane, tetrols such as erythritol and pentyerythritol, Hexols such as mannitol and sorbitol. ■

For reasons of ease of use of the resulting chlorinated polyether polyols, preferred polyols are the triols. A particularly preferred triol that is cheap and readily available is is glycerin.

The molar ratio of epichlorohydrin and initiating polyol is not critical and can be used in a wide range of ratios vary. It regulates the hydroxylindex of the resulting Polyether-polyols. For the production of rigid polyurethane foams one generally uses polyether polyols, which have a hydroxylindex or a hydroxyl. Hydroxyl number between about 250 and 80.0 mg KOH / g polyol.

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For the production of rigid, non-flammable polyurethane foams According to the invention particularly preferred, chlorinated polyether polyols are those which are obtained from the addition of 2 to 6 mol Epichlorohydrin derive from 1 mole of glycerol.

The temperature of the reaction between the polyhydric alcohol and the epichlorohydrin will of course vary depending on the reactants used, their amounts and the duration of the reaction. In general, the reaction, however, is carried out in a temperature range of about 50 to 150 ⁰ C. The reaction time also varies depending on the temperature of this reaction, the reactants used and the amounts thereof used. In general, a reaction time of the order of about 30 minutes to 10 hours is used.

The acidic catalyst can be any of the known catalysts for this type of reaction, e.g. B. boron trifluoride, Tin (H) chloride, aluminum trichloride, titanium tetrachloride, etc. A particularly preferred catalyst is boron trifluoride. the Use of this catalyst is beneficial as it does the work to neutralize and recover the catalyst allows to leave out which usually before the reaction with the organic polyisocyanates are indispensable. In this case, the amount of boron trifluoride used in the manufacture of the dimensionally stable polyurethane foams according to the invention present must be calculated, with the remaining amount of boron trifluoride which is already present in the chlorinated polyether polyol, is taken into account.

The derived from epichlorohydrin, chlorinated polyether polyols can be used alone or in a mixture, for. B. with non-halogenated polyether polyols or with other halogenated, Polyether polyols such as brominated polyether polyols,

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are used for the production of polyurethanes *

The relative proportion of such chlorinated polyether-polyols and chlorbrominated polyether-polyols in the 'polyether-polyolgeinisch used can vary to a fairly large extent. The self-extinguishing properties of the resulting polyurethane are of course do the better the higher this proportion is. Self-extinguishing, rigid, in accordance with the ASTIt D. 1692 standard Polyurethanes can be obtained by using polyether-polyol mixtures which are one or more non-Hai o-genated Polyether-polyols and at least 25% by weight, preferably 40 to 80% by weight, of .chlorinated, epichlorohydrin-derived Contain polyether polyols.

The rigid polyurethane foams produced according to the invention are known in a manner by reacting chlorinated polyether polyols or mixtures of non-halogenated ones Polyether polyols and chlorinated polyether polyols derived from epichlorohydrin and organic polyisocyanates in the presence of a propellant and one or more Catalysts for the reaction, optionally water, of emulsifiers and / or stabilizers, of fillers, pigments, etc. produced. .

The chlorinated polyether polyols derived from epichlorohydrin are for the production of polyurethane hems after all suitable for conventional foaming processes. - ·

All ongoing for the production of rigid polyurethane foams Organic isocyanates used are suitable. Particularly preferred isocyanates are those which two on one aromatic ring or on two different, condensed or Rings connected by an aliphatic bridge have bonded isocyanate groups. In particular, methylenebis (4 ^ phenyl isocyanate) in the pure or partially polymerized state, tolylene diisocyanate in the pure state or in the form of

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Mixtures of isomers and naphthalene-1,5-diisocyanate are used.

The theoretical amount of polyisocyanate required for manufacture is in a known manner depending on the Hydroxylindex of the polyether polyol (s) and optionally the the amount of water available. It is advantageous to use a small excess of one polyisocyanate Isocyanate index or an isocyanate number of 105 to 120 to guarantee. . ·

The catalyst used can be any of those for this Purpose of use be known catalysts, in particular tertiary amines such as triethylenediamine (1,4-diazabicyclo [2.2.2joctane), Triethylamine, trimethylamine, dimethylaminoethanol and metal salts such as salts of antimony, tin and iron. A a particularly preferred catalyst is triethylamine.

The amount of catalyst can vary to a certain extent; it affects the mechanical properties of the resulting material Foam. In general, from 0.1 to 3% by weight is used Catalyst, based on the polyether-polyol or the mixture of polyether-polyols.

The choice of propellant is not critical. Known propellants are suitable without exception, in particular water, chlorofluoroalkanes such as trichloromonofluoromethane (RH) »dichlorodifluoromethane (R12) and trichlorotrifluoroethane (RH 3).

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

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It may be advantageous to use the polyurethane foams manufacture of small amounts of a surfactant, which contributes to the improvement of the cell structure, preferably from 0.2 to 2% by weight, based on the polyether polyol or the mixture of polyether polyols.

The invention is illustrated in more detail by means of the following examples.

Examples 1 and 2 relate to the preparation of epichlorohydrin oligomers in the presence of boron trifluoride as a catalyst. Examples 3 to 16 relate to the production of rigid ones Polyurethane foams using epihlorohydrin oligomers, to which boron trifluoride was added in various amounts became.

Example 1 '■. .-

460 g of glycerol and 0.6 g of boron trifluoride diethyl etherate are introduced at ambient temperature into a 5 l glass reaction vessel which is immersed in a thermostated ice bath and is equipped with a stirrer and a thermometer Epichlorohydrin is added at such a rate that the temperature is kept constant between 60 and 70 ^° C. The addition of epichlorohydrin is continued until 1388 g of epichlorohydrin have been added, an operation of this type lasting about 3 hours.

The resulting epichlorohydrin oligomer is as such without any purification to make rigid, non-flammable ones Polyurethanes useful in accordance with the invention. Its main characteristics are the following:

- specific weight, 20 ⁰ C 1.34-

- Viscosity at 20 ⁰ G, poise «160

- Chlorine content, wt .-% ■. 28.5

- Hydroxylindex, mg KOH / g polyol - 4-54-

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- mean molecular weight, measured 370

- Water content,% by weight 0.1

- BF ^ content, wt% 0.0152.

Example 2

It is according to the procedure of Example 1 under Use of 460 g glycerine, 0.7 S boron trifluoride etherate and 1850 g epichlorohydrin worked. The properties of the resulting epichlorohydrin oligomers that have not been freed from the catalyst are the following:

- specific weight, 20 ⁰ C '1.34

Viscosity at 20 ^° C., poise 210

- Chlorine content,% by weight 30.5

Hydroxyl index, mg KOH / g polyol 364

- mean molecular weight, measured 462

- Water content,% by weight 0.1

- BF , content, wt .-? & 0.0147.

Examples ^ to 11

These examples relate to the production of polyurethane foams according to the invention from produced according to Example 1, chlorinated polyether polyol.

Example 3 relates to the production of a polyurethane foam using a crude, not freed from the catalyst, chlorinated polyether polyol without additional addition of boron trifluoride.

Examples 4 to 8 relate to the use of the chlorinated polyether polyol which is added before foaming Contains boron trifluoride.

Examples 9 to 11 relate to the use of the chlorinated polyether polyol at the moment of foaming Boron trifluoride was added.

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100 g chlorinated polyether-polyol according to Example 1, to which boron trifluoride (Examples 4-8) "was added if necessary," 0.5 g of a silicone (DG 193), 1.5 S triethylamine, 37 g Trichlorofluoromethane (B11) and optionally boron trifluoride (Examples 9 to 11) introduced. The mixture is stirred so that that it becomes completely homogeneous. 115.8 g of crude methylene bis (4-phenylene isocyanate) are then added.

The resulting mixture will. Stirred for 20 seconds, then in one Poured form and allowed to react at ambient temperature.

The start times measured from the end of mixing and the rise times measured from the end of the start result from the following Table I. The boron trifluoride content of various specimens is also listed herein.

In Table I, the foams obtained are characterized by their apparent, specific weight and characterized by their dimensional stability and dimensional stability.

The dimensional stability is measured on a foam sample of 15 × 15 × 1 cm, the thickness of which corresponds to the direction of expansion of the foam. This test specimen is kept under ambient humidity at a temperature of 100 ^° C. for 7 days. The two center lines are then measured to calculate the mean length of the center lines after aging. The dimensional stability is expressed as the change in the mean length of the center lines as a percentage of the mean initial length.

The foams produced with the chlorinated, BF-free polyether-polyol suffered so great deformations at 100 ⁰ G- that these could no longer be measured as a result of the loss of flatness of the test specimens. ■

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• - 12 -

Example 3 shows that about 150 ppm of residual boron trifluoride already improve the dimensional stability of the foam compared to the foams which do not _{contain BF 3} is measurable.

Examples 4 to 11 show that the increase in the boron trifluoride content by adding to the polyether-polyol in amounts within the preferred limits either prior to foaming (Examples 4 to 8) or at the same time as foaming with the foaming catalyst and the blowing agent (Examples 9 to 11) the dimensional stability of the foams is very high noticeably improved.

Examples 12 to 16

These examples relate to the manufacture of polyurethane foams using epichlorohydrin oligomer prepared according to Example 2.

Example 12 relates to the use of the catalyst not freed oligomers.

Examples 13 to 16 relate to the use of the Polyether-polyol containing boron trifluoride, which before the Foaming was added (see Table II below).

The polyurethane sci-rooms are manufactured according to a working method which corresponds to that described above, except that only 89.6 g of methylene bis (4-phenyl isocyanate) were used to the same isocyanate index as in Examples 3-11 can be obtained.

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Table I-

In the case of the production of the foam play BF, content of the start-climb weight% in the time-chlorinated polyoil sec .: sec.

Foam properties apparent, dimensional stability specificity at 100 ° C, weight change in kg / m3 initial dimensions in percent

0.015

15 33

53

0.059 0.066 0.073 0.113 0.266

15th 38 32 5 9.0 14th 33 31, 5 0.3 15th 35 31, 5 0.9 15th 32 31, 1.0 20th 29 32 2.0

9 0.078 15th 38 . 34 9.0 10 0.141 17th 33 37 2.5 11 0.297 21 31 37 2.1

Table II

Example production of the foam game BI ¹ ^ content start climb

Wt .-% in time · chlorination-j

th polyol sec. sec.

Properties of the foam apparent, dimensional stability specificity at'100 ⁰ C, weight change in

kg / πκ initial dimensions in percent

0.0147

36

33

10.5

13th 0.0565 5 30th 32 14th 0.0781 6th 34 32 15th 0.1063 VJl 25th 31 16 · 0.2331 VJI 29 32

3.5 0.2

2.5

2.5

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Claims (9)

Claims . Process for the production of incombustible, rigid poly- ' urethane foaming by reaction of an organic polyisocyanate with at least one chlorinated polyether polyol, that from the addition of epichlorohydrin to a monomeric polyol having at least three hydroxyl radicals per molecule arises, in the presence of a customary catalyst and a customary blowing agent, marked thereby e t that the reaction is carried out in the presence of boron trifluoride in the free or complex-bound state. 2. The method according to claim 1, characterized marked eichn e t that the boron trifluoride is added to the chlorinated polyether polyol prior to foaming. 3. The method according to claim 1, characterized in that that the boron trifluoride, the catalyst and the blowing agent are chlorinated at the moment of foaming Adding polyether-polyol. 4-, method according to claim 1, characterized in, that one uses a chlorinated polyether polyol which has not been purified from the catalyst and which results from the addition of epichlorohydrin to a monomeric polyol having at least three hydroxyl radicals in the presence of boron trifluoride originates as a catalyst. 5- The method according to any one of the preceding claims, characterized characterized in that a mixture of chlorinated polyether polyol and non-halogenated polyether polyol used. 409822/1030 6. The method according to any one of the preceding claims, characterized marked that one is in attendance an amount of boron trifluoride between 0.03 and 6% by weight, based on the chlorinated polyether-polyol, works. 7. "The method according to claim 6, characterized in that g e k e η η ζ e i c h η e t "that one is in the presence of an amount of boron trifluoride between 0.04-5 and 3% by weight, based on the chlorinated Polyether-polyol, works, 8. The method according to one of the preceding claims, characterized g e k e η η ζ ei c h η e t that, the chlorinated polyether glycol from the addition of epichlorohydrin to glycerine in the presence of BE-. 9. Rigid polyurethane foams, made by the process according to one of the preceding claims. 4 0 9 8 2 2 /. T 0 3 0