DE2718512A1 - METHOD FOR PREPARING POLYISOCYANATE COMPOSITIONS - Google Patents

Description

PATENT LAWYERS

DR. -ING. H. FINCKE DIPU.-ING. H. BOHR DIPL.-ING. S. STAEGER DR. Rer. nat. R. KNElSSL

PA Dr. FmJ ₁ C Bohr - Slaeger - Dr Kneiul - Mullcrstr. 31 - 8000 Munich p

8 MONCHtN β, Muüivstrasse 31 Telephone: (089) 'JOiOtO Telegrams: Claims Munich Tel: 5 239 03 cloim d

April 26, 1977

24252 - Dr.K / Hö

Please indicate in the answer

IMPERIAL CHEMICAL INDUSTRIES LTD. London - Great Britain

"Process for the preparation of polyisocyanate compositions"

PRIORITY: May 21, 1976 - Great Britain - 21061/76

The invention relates to the production of reaction products from tolylene diisocyanate and oxypropylated triols, to mixtures of such products with isocyanates and to the use of these products and mixtures in the production of polyurethane foams.

-2-

7098A9 / 0701

Bank details. · Bayer. Vereinsbank Munich, account 620 404 ■ Postal check account: Munich 270 44-802

In GB-PS 994 890 compositions are described which consist essentially of allophanate polyisocyanates, which be obtained by using an excess of an organic diisocyanate with a urethane isocyanate general formula R (OOCNHRNCO), where R is an organic radical, namely the radical of a monohydroxy or polyhydroxy compound after the hydroxyl groups have reacted with isocyanate groups, η is an integer from 1 to 6 and represents the functionality of the hydroxy compound and R stands for a divalent organic radical, converts, the reaction being carried out under conditions such that essentially one molecule of diisocyanate is present with each Urethane group reacts, which is evident from the measured isocyanate group content of the reaction mixture results.

If the group R in the urethane isocyanate is the same as the remainder of the organic diisocyanate, then the products be prepared in a single step by reacting the organic diisocyanate with the hydroxy compound.

The products of GB-PS 994 890 are said to be essentially allophanate isocyanates, although clear too it is stated that the exact nature of these products has not been fully elucidated.

GB-PS 1,296,652 also relates to allophanate polyisocyanates which are said to be obtained when an N-substituted carbamic acid ester with a polyisocyanate with at least two aromatically bound isocyanate groups in the presence of an alkylating agent.

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It has now been found that valuable liquid polyisocyanates are obtained if one uses an excess of ethylene diisocyanate with an oxypropylated triol having a molecular weight of 200 to 800 in the absence of an alkylating agent reacts under such conditions that a further reaction takes place after the initial urethane formation. These products are mostly liquids. Such fluids have advantages in that they are beneficial when standing maintain their liquid state for several months. They are particularly suitable for the production of flexible Polyurethane foams, in particular cold-curing moldings made from flexible foam.

The invention therefore relates to a process for the preparation of polyisocyanate compositions which is carried out thereby is that one at a temperature of 120 ° C or above at least 4 molar proportions of tolylene diisocyanate with an oxypropylated triol with a molecular weight of 200 to 800 reacts in the absence of an alkylating agent under such reaction conditions that after the first urethane formation reaction another reaction takes place.

Any tolylene diisocyanate can be used in the present process, that is, any of the isomeric tolylene diisocyanates or any mixture of these isomers can be used. It is preferred to use a mixture of 2,4- and 2,6-tolylene diisocyanates to be used in which the isomers are present in a ratio of approximately 80:20. Such a mixture from tolylene diisocyanate 2,4 and 2,6 isomers is commercially available available. Although the isomer ratio is not always exactly 80:20, this ratio is sufficiently close to this Value that the commercial products are specified with this ratio.

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Preferred molar proportions of tolylene diisocyanate are 4 to 30 molar proportions per molar proportion of oxypropylated triol.

Any oxypropylated triol with a molecular weight of 200 to 800 can be used. Such connections are prepared by adding propylene oxide to a triol, preferably an aliphatic triol, to the desired molecular weight has been obtained. The oxypropylated triols are not necessarily uniform Compounds, but they are generally mixtures of compounds of different molecular weights, accordingly the number of molecules that have added to each triol molecule. Such mixtures have an average Molecular weight from 200 to 800.

Examples of triols as starting materials for the production of the oxypropylated triols are glycerol, trimethylolpropane, Trimethylolethane, hexanetriol, triethanolamine, triisopropanolamine and similar triols.

The oxypropylated triol preferably has an average Molecular weight in the range from 250 to 400.

Oxypropylated triols based on glycerol are preferred.

It is preferred that a small amount of a stabilizing agent such as an acid chloride be used during the reaction is present between the triol and the tolylene diisocyanate.

Examples of stabilizers that can be used are benzoyl chloride, acetyl chloride, toluoyl chlorides, Propionyl chloride and thionyl chloride.

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The amount of stabilizer can be quite small. For example, less than 0.1% by weight of stabilizing agent, such as 0.01 to 0.1% by weight, based on the tolylene diisocyanate be used.

When a triol with three hydroxyl end groups with an isocyanate is converted, then urethane formation takes place as the first reaction from the isocyanate and hydroxyl groups, however, the present reaction will take place under such conditions stated that a further reaction takes place after this first urethane formation. More reactions that take place are the formation of allophanates through the reaction of excess isocyanate groups with urethane.

Other reactions can also take place. The present invention is not directed to any particular reaction mechanism or limited to a reaction product with certain formulas. The exact nature of the final composition was not made fully characterized. Indeed, in the case of such compositions, such characterization is extremely difficult perform.

A suitable temperature for the reaction is within the range from 120 to 180 ° C., preferably from 130 to 150 ° C. The reaction time can vary considerably within this temperature range, depending on the desired degree of conversion. Times of up to 12 hours have proven to be useful .

In one method of carrying out the present process , the oxypropylated triol and the tolylene diisocyanate are premixed and then heated to the desired temperature.

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In another and preferred method, the cxypropylated triol can slowly give the tolylene diisocyanate, which is raised to the reaction temperature is held, for a suitable period of time, for example 1 st, are added, followed by heating continued as needed.

Finally, the process can also be carried out by previously separating the urethane from the oxypropylated triol and the Manufactures tolylene diisocyanate and then heated this product with excess tolylene diisocyanate. However, it will be a single stage Process in which the entire preparation is carried out in one step is preferred.

The products obtainable according to the invention are generally Liquids. These liquids have a shelf life of several months.

The products are suitable for the production of flexible polyurethane foams, especially fittings.

Thus, according to the invention, a method for producing polyurethane foams is also proposed, which is carried out by making a product of the present process with a polymer containing at least two isocyanate Has reactive end groups, reacts under such conditions that a foam-forming gas is generated ..

It has also been found that compositions comprising a product of the present invention together with a portion contain a mixture of polyphenyl polyisocyanates with methylene bridges and / or a proportion of tolylene diisocyanate, are particularly suitable for the production of molded polyurethane foam pieces. Such arrangements are particularly preferred

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Settlements with 10 to 40% mixed methylene bridges Polyphenyl polyisocyanates, based on the total weight of the isocyanate composition.

Mixtures of polyphenyl polyisocyanates containing methylene bridges are well known in the art and are often referred to as raw or polymeric MDI or as raw or polymeric Dipheriylmechandiisocyanat described. They are made by that the crude amine mixture is phosgenated by condensation of aniline and formaldehyde in the presence of catalysts, such as hydrochloric acid. It is known that these mixtures have different proportions of diisocyanate and contain higher functional polyisocyanates. Any such mixture can be used in the above compositions.

All known polymers containing isocyanate-reactive end groups on iron can be used, in particular polymers with hydroxyl end groups, especially polyether polyols.

Suitable polyether polyols can be reacted in a known manner one or more alkylene oxides can be prepared with a compound containing several active hydrogen atoms. Suitable alkylene oxides are ethylene oxide, propylene oxide, epichlorohydrin, 1,2-butylene oxide, 2,3-butylene oxide and styrene oxide. Mixtures of two or more oxides can optionally be used, such as mixtures of ethylene and propylene oxide. as Another variant can be the compound containing the active hydrogen with two or more alkylene oxides in successive Stages are implemented, for example propylene oxide in the first stage and ethylene oxide in the second stage or conversely, ethylene oxide is used in the first stage and propylene oxide in the second stage. Connections that have multiple

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contain active hydrogen atoms with which the alkylene oxides can be implemented are water, ethylene glycol, propylene glycol, Diethylene glycol, glycerine, trimethyiolpropane, triethanolamine, Sorbitol, sucrose and pentaerythritol. Mixtures of the same can also be used.

Particularly suitable polyether polyols for use in

polyurethane production processes according to the invention are poly-

oxypropylene and poly (oxypropylene-oxyethylene) polyols with 2 to 4 hydroxyl groups per molecule.

Polyether polyols modified by the in situ polymerization of vinyl monomers can also be used are to produce a polyol that contains a proportion of vinyl polymers or copolymers.

Preferred polyether polyols have average molecular weights in the range from 1000 to 10,000, preferably from 2000 to 7000, calculated from the measured hydroxylwart.

In the manufacture of polyurethane foams from the products of the present invention or from compositions containing containing these products, any of the known foam-making techniques can be used. So can any of the usual Propellants are used. Examples of suitable blowing agents are water, which is formed with the polyisocyanate of carbon dioxide reacts, and inert volatile liquids that are under the influence of exothermic heat or due to a pressure release (if a foaming process is used) evaporated. Examples of such liquids are halogenated Hydrocarbons with boiling points not above 100 C and preferably not above 50 C at atmospheric pressure, especially chlorofluorinated hydrocarbons, e.g. Trichlorofluoromethane and dichlorofluoromethane. The amount

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the propellant is selected in a known manner so that Foams with the desired density are created. In general, from 0.05 to 0.3 mol of gas per 100 g of reaction mixtures are suitable. If necessary, the density of the product can be modified by "overpacking" i.e. that the foaming of the reaction mixture is carried out in a closed mold, the volume of which is less than that which would be taken up by the resulting foam if the reaction mixture were allowed to rise freely.

The foam-forming reaction mixture can also contain other conventional ingredients for such reaction mixtures. So the reaction mixture can contain the following additives: catalysts, such as tertiary amines and organic tin compounds, surfactants, such as low molecular weight dimethylsiloxane polymers, crosslinking agents or chain extenders, such as triethanolamine, ethylene glycol and m-phenylenediamine, flame retardants such as trishaloalkyl phosphates, and fillers such as barium sulfate.

The components of the foam-forming reaction mixture can be mixed together in any convenient manner, wherein for example, any mixing device described in the literature for this purpose is used. If necessary, can some of the individual components can be premixed to reduce the number of component streams involved in the final Mix stage must be brought together. It is often convenient to use a two-stream system, with one stream from consists of the polyisocyanate and the second stream contains all other components of the reaction mixture.

When using the polyisocyanate composition of the present invention either alone or in admixture with other isocyanates mentioned above, it is possible to use a

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to achieve better curing of foam moldings and thus reducing the time during which the fitting must be in the mold. A good quick hardening in the Mold to a reasonable green strength is on a production line important where shorter dwell times in the mold lead to increased production.

In an automobile seat cushions transferred to a springless Base are mounted. Vibrations. These are maximum at a frequency close to the fundamental frequency of the main body and therefore can cause inconvenience to passengers. It has now been found that pillows made of foams which are made from the isocyanate compositions of the invention especially when using the polyisocyanate composition of the present invention together with mixtures of methylene bridges. Polyphenyl isocyanates are used, give about 3O% less vibration transmission than a corresponding cushion made from consists of a foam which consists of mixtures of unmodified a ToIylene diisocyanate and mixtures of methylene bridges Polyphenyl polyisocyanates has been produced.

The invention is illustrated in more detail by the following examples, in which the parts and percentages are expressed by weight are.

EXAMPLE 1

1740 parts of an 80/20 mixture of the 2,4 / 2,6-tolylene diisocyanate isomers (TDI) and 0.6 parts of benzoyl chloride were placed in a reaction vessel equipped with a stirrer, a Thermometer and a cooler. The mixture was heated to 130 ° C. with stirring under a nitrogen blanket and 31O parts of oxypropylated glycerin with a mol-

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kularcjewicht of 310 were during a period of 1 st added at 130 to 13 5 ° C. The heating was at 2 1/2 st 130 to 13 5 ° C, whereupon the product to room temperature was allowed to cool. The product, a slightly viscous, pale yellow liquid, had an isocyanate value of 33.5%.

Sufficient 80 / 20-2.4 / 2.6 TDI was added to give a composition with an isocyanate value of 40.0% was (sample 1).

A second sample was prepared in a similar manner to (1), however, a temperature of 100 ° C was used throughout. An isocyanate value of 3 5.5% was obtained. This material was also diluted with 80 / 20-2.4 / 2.6-TDI, so that an isocyanate value of 40.0% was obtained (sample 2).

Samples 1 and 2 and a sample made from 80 / 20-2.4 / 2.6 TDI were used ! ti with raw MDI (defined below) in a ratio of 80:20 mixed so that isocyanate mixtures 3, 4 and 5 were obtained. According to the following formulations were flexible foam moldings produced.

Table 1

foam

oxypropylated glycerine + 14% ethylene oxide tips, MW 5300

water

Dabco 33 LV (33% triethylenediamine in dipropylene glycol)

Dimethylaminoethanol

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A. B. C. Parts by weight 100 1OO 100 3.0 3.0 3.0 0.7 0.7 0.7 0.3 0.3 0.3

Continuation of table 1

Foam A B

low molecular weight polydimethylsiloxane O, O7 O, O7 O, O7

oxyethylated octylphenol 1.5 1.5 1.5

Isocyanate mixture 3 45.9 - -

Isocyanate mixture 4 - 45.9 -

Isocyanate mixture 5 - 4O, O

The ingredients were stirred together at 20OO rpm and in an isolated mold, which had been heated to 30 ° C, transferred, whereupon the mold was closed. It became a very minor one Degree of upper packing used.

The mold was made of aluminum and was marked with "Easilease 4O1", a suitable mold release agent, coated.

It was found that foams B and C were added for comparison purposes showed essentially the same moderate cure. The foam A had achieved a much better cure, what resulted from the nature of the fitting.

The use of the products according to the invention results in an improvement in the curing of flexible foam moldings.

The crude MDI used in the above example and in the following examples was a mixture of methylene bridges Polyphenyl polyisocyanates with 45% diphenylmethane diisocyanates and with an average functionality of

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2.8. Ls had been prepared by phosgenating the mixture of polyarylamines obtained by condensing aniline with formaldehyde in a molar ratio of 1.85 / 1 in the presence of hydrochloric acid.

EXAMPLE 2

A polyisocyanate composition was prepared under the same reaction conditions as in Example 1, except that 870 parts of a 30 / 20-2.4 / 2.6 TDI, 0.35 part of benzoyl chloride and 295 parts of an oxypropylated glycerol with a molecular weight of 590 were used became. After cooling, the product, a slightly viscous liquid, had an isocyanate value of 27.2%. This material was diluted with sufficient 80 / 20-2.4 / 2.6 TDI that an isocyanate content of 37.0% was obtained (Sample 6).

EXAMPLE 3

A polyisocyanate composition was prepared under the same reaction conditions as in Example 1 except that 652 parts of 80/20 to 2.4 / 2,6-TDI, 0.35 parts of benzoyl chloride and 153 parts of a propoxylated glycerol with a kulargewicht Moler were used 410 . The product from the reaction had an isocyanate value of 30.0%. The mixture was mixed with sufficient 80 / 20-2.4 / 2.6 TDI that an isocyanate value of 38.5% was obtained (Sample 7).

Samples 6 and 7 were mixed with crude MDI in a ratio of 80:20 to give isocyanate mixtures 8 and 9, respectively. Flexible foam moldings were made according to the formulations of Table 2 using the same procedure that was used in making Foams A, B and C.

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TABEL

• ScJiaum D Look K Look F Look G Look H Foam I. Schium J 100 CKypropylated glycerine rait
14% ethylene oxide tips (MW 5300) 100 100 100 - - - - water 3.0 3.0 3.0 3.0 3.0 3.0 3.0 Dabco 33LV (33% triethylenediamine
in dipropylene glycol) 0.7 0.7 0.7 0.7 0.7 0.7 0.7 Dimethylaminoethanol 0.3 0.3 0.3 0.3 0.3 0.3 0.3 low molecular weight polydimethyl
siloxane 0.07 0.07 0.07 0.07 0.07 0.07 0.07 oxyethylated nonylphenol 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Ispcyanate mixture 8 49.3 - - - - - - Organic isocyanate 9 - 47.7 - - - - - Isocyanate mixture 5 - - 39.5 - - 43.5 39.0 Isccyanate mixture 3 - - - 51.3 45.6 - - CKypropylated glycerine with
12% ethylene oxide tips, (MW 3000) - - - 100 - 100 - CKypropylated glycerine with
14% EthylenecKyd tips (MG 5300)
modified with 10% 60 / 40-
Methy Imethacry lat / Acry lonitri 1 100

A comparison of foam shapes D, E and F is shown after one Time of 10 min to demold showed that the molded pieces D and E showed improved curing compared to the molded part F (made from unmodified isocyanate).

Similar comparisons of fittings G and I or H and J showed the improved curing with isocyanate mixtures, prepared according to the invention compared to the use of unmodified isocyanates.

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Claims (15)

PATENT CLAIMS 1. A process for the preparation of Polyisocyanatzusummensetzungen, characterized in that at a temperature of 120 ⁰ C or higher at least 4 molar proportions of tolylene diisocyanate with a propoxylated triol having a molecular weight of 200 to 800 in the absence of an alkylating agent is reacted under reaction conditions such that a further reaction takes place after the first urethane formation reaction. 2. The method according to claim 1, characterized in that as tolylene diisocyanate, a mixture of 2,4- and 2,6-tolylene diisocyanate is used in a ratio of approximately 80:20. 3. The method according to claim 1 or 2, characterized in that that 4 to 30 molar proportions of tolylene diisocyanate are used. 4. The method according to any one of the preceding claims, characterized in that the oxypropylated triol has an average molecular weight of 250 to 400. 5. The method according to any one of the preceding claims, characterized in that an oxypropylated triol oxypropylated glycerin is used. 709849/070; ORIGINAL INSPECTED 6. The method according to any one of the preceding claims, characterized in that a stabilizing agent during the reaction is present. 7. The method according to claim 6, characterized in that an acid chloride is used as a stabilizing agent. 8. The method according to claim 6 or 7, characterized in that the stabilizing agent is used in an amount of 0.01 to 0.1%, based on the tolylene diisocyanate. 9. The method according to any one of the preceding claims, characterized in that the reaction is carried out at a temperature of 120 to 180 ° C. 10. The method according to claim 9, characterized in that a temperature of 130 to 150 C is used. 11. Use of a polyisocyanate composition prepared according to one of claims 1 to 10 for the production of a polyurethane foam by reaction with a polymer which has at least two isocyanate-reactive end groups under such conditions that a foam-generating gas is formed. 12. Use according to claim 11, characterized in that the polyisocyanate composition is used together with a portion of a mixture of polyphenyl polyisocyanates containing methylene bridges and / or a portion of tolylene diisocyanate . 13. Use according to claim 12, characterized in that the polyisocyanate composition together with 10 to 40% of a mixture of polyphenyls containing methylene bridges 709849/0701 polyisocyanates, based on the total weight of the polyisocyanate composition, is used. 14. Use according to one of the claims 11, 12 or 13, thereby characterized that as rr.it isocyanate reactive Polymer a polyoxypropylene or poly (oxypropylene-oxyethylene) pclyol with 2 to 4 hydroxyl groups per molecule is used. 15. Use according to claim 14, characterized in that the polyol has an average molecular weight in the range from 2000 to 7000. or .., ng «FVINQ. P. 9UiQLi ns. 70984970701