MXPA00011662A - Silylated double metal cyanide complex catalysts - Google Patents

Abstract

The amount of high molecular weight impurity present in a polyether polyol produced by alkoxylation of an active hydrogen-containing initiator using a double metal cyanide complex catalyst may be advantageously lowered by treating the catalyst prior to use in polymerization with a silylating agent. Suitable silylating agents include trialkyl halosilanes and trialkyl alkyoxysilanes. The higher purity polyether polyols thereby produced are particularly useful in the preparation of slab and molded polyurethane foams, which tend to collapse or become excessively tight when elevated levels of high molecular tail are present in the polyether polyol.

Description

FIELD OF THE INVENTION This invention belongs to a method for improving the effectiveness of a double metal cyanide complex. More particularly, the invention relates to contacting such a catalyst with a silylating agent whereby the silylated catalyst thus obtained is capable of producing polyether polyols having reduced levels of high molecular tail. Such polyether polyols have high processing latitude in the preparation of the molded and laminated polyurethane foam.

BACKGROUND OF THE INVENTION Polyurethane polymers are prepared by the reaction of a di- or polyisocyanate with a polyfunctional isocyanate-reactive compound, in particular, the polyether-functional hydroxyl polyols. There are numerous classes of polyurethane polymers recognized in the art, for example cast-cast elastomers, RIM polyurethane, microcellular elastomers, and laminated and molded polyurethane foam. Each of these polyurethane varieties presents unique problems in formulation and processing. Ref No. 125038 Two of these higher volume categories of polyurethane polymers are molded and laminated polyurethane foam. In the laminated foam, the reactive ingredients are provided inside a mobile conveyor and allowed to rise freely. The resulting laminated foam, often 6 to 8 feet (2 to 2.6 m) wide and high, can be sliced into thinner sections for use as seat cushions, carpet shavings, and other applications. The molded foam can be used for curved foam parts, for example, car seat pads.

In the past, polyoxypropylene polyether polyols useful for laminate and molded foam and plate applications have been prepared by means of base-catalyzed propoxylation of suitable hydro initiators such as propylene glycol, glycerin, sorbitol, etc. , producing the respective polyoxypropylene diols, triols, and hexols. As has been well documented, a rearrangement of propylene oxide to allyl alcohol occurs during propoxylation catalyzed by a base. The unsaturated allylic alcohol supports a hydroxyl group capable of reacting with the propylene oxide, and its continuous generation and propoxylation produces increasingly large amounts of unsaturated polyoxypropylene monools having a broad molecular weight distribution. As a result, the actual functionality of the produced polyether polyols is significantly decreased from the "normal" or "theoretical" functionality. In addition, the monol generation places a relatively low practical limit on the molecular weight obtainable. For example, a diol (2000 Da of equivalent weight) of molecular weight of 4000 Da (Dalton) catalyzed with a base may have a measured unsaturation of 0.05 meq / g, and must thus contain 30 mole percent of monolithic species of unsaturated polyoxypropylene. The resulting actual functionality should be only 1.7 less than the "nominal" functionality of 2 expected for a polyoxypropylene diol. As this problem becomes even more severe with the increase in molecular weight, the preparation of the polyoxypropylene polyols having equivalent weights higher than about 2200-2300 Da is impractical to use the conventional base catalyst.

The double metal cyanide complex ("DMC") catalysts such as zinc hexacyanocobaltate complexes are found to be catalysts for propoxylation about 30 years ago. However, its high costs, accompanied by its modest activity and the difficulty of - removing significant amounts of catalyst residues from the polyether product, hinder commercialization. However, the level of unsaturation (eg, the "monol" level) of the polyoxypropylene polyols produced by these catalysts was low.

The relatively modest polymerization activity of these conventional double metal cyanide complex catalysts has been recognized as a problem by workers in the field. Recently, as indicated by U.S. Patent Nos. 5,470,813, 5,482,908, 5,545,601, and 5,712,216 researchers at Arco Chemical Company have produced substantially amorphous DMC complex catalysts produced with exceptional activity, which have also been found to be capable of producing polyols of polyether having levels of unsaturation in the range of 0.002 to 0.007 meq / g (levels previously obtainable only through the use of certain solvents such as tetrahydrofuran). The polyoxypropylene polyols thus prepared were found to react in a quantitatively different manner from "low" unsaturated polyols in certain applications, notably cast-molded elastomers and microcellular foams. However, the substitution of such polyols by their catalyzed analogues with a base in the formulations of the molded and laminated foam is not simple. In molded foams, for example, the stiffness of the foam increases to such an extent that the necessary pressing of the foams after molding becomes difficult if not impossible. In foams molded as well as in laminated foams, the collapse of the foam often occurs, ridiculing such foams unable to produce. These effects occur even when the current high functionality of such polyols is determined to be decreased by the addition of low functionality polyols to achieve similar functionality as that of the base-catalyzed polyols.

The polyoxypropylene polyols catalyzed with DMC have an exceptionally narrow molecular weight distribution, as can be seen from the examination of the gel penetration chromatographs of polyol samples. The molecular weight distribution is often even narrower than that of the base-catalyzed analog polyols, particularly in the range of the largest equivalent weight, for example. They generally obtain polydispersities smaller than 1.5, and polydispersities in the range of 1.05 to 1.15 are common. In view of the low levels of unsaturation and the low polydispersity, it is surprising that the polyols catalyzed by DMC do not prove to be replacements "in small quantities" for polyols catalyzed by a base in polyurethane foam applications. Because propoxylation with modern DMC catalysts is highly efficient, this could be very desirable because it is capable of producing DMC-catalyzed polyoxypropylene polyols that can be used in the applications of laminated and molded polyurethane foam without causing excessive foam stiffness or foam collapse.

BRIEF DESCRIPTION OF THE INVENTION Now it has been discovered that. Polyether polyols containing polymerized propylene oxide and which mimic the behavior of base-catalyzed analogs in laminated and molded polyurethane foams can be obtained using a double metal cyanide complex catalyst if the catalyst is the first in be treated with a silylating agent.

DETAILED DESCRIPTION OF THE INVENTION Intensive research into the chemical and physical characteristics of polyoxypropylene polyols has led to the discovery that despite the narrow molecular weight distribution and low polydispersities of the catalyzed polyols by means of cyanide complex catalysts of highly active, substantially amorphous double metal, small, high molecular weight fractions are responsible in large part for the excessive stiffness of the foam (stabilization) and the collapse of the foam.

A comparison of gel permeation chromatograms of base-catalyzed polyols and catalyzed with DCM exhibit significant differences. For example, a polyol catalyzed by a base exhibits a significant "front" portion of the low molecular weight oligomers and polyoxypropylene monools before the peak or peak of the main molecular weight. After the maximum, the percentage of the weight of the high molecular weight species falls rapidly. A similar chromatography of DMC-catalyzed polyol reveals a tightly centered maximum with a very small "front" portion of low molecular weight, but with a high molecular weight portion ("high molecular weight" tail) that shows the presence of measurable species in very-high molecular weights. Due to the low concentration of these species, generally a little less than 2-3 weight percent of the total, polydispersity is low. However, intensive research has revealed that high molecular weight species, despite their low concentrations, are largely responsible for the abnormal behavior of DMC catalyzed polyols in molded and laminated polyurethane foam applications. This implies that these high molecular weight species exert a similar effect as that of the surfactant which alters the solubility and therefore the phase outside the growth of the polyurethane polymers during the isocyanate-polyol reaction.

By means of fractionation and other techniques, it has been determined that the high molecular weight tail can be divided into two molecular weight fractions based on the influence of these different effects of the fractions. The first fraction, determined here as an intermediate "molecular weight tail", consists of polymer molecules having molecular weights of a range of approximately 20,000 Da to 400,000 Da, and greatly alters the stiffness of the foam in the molded foam and foam laminated high resistance (HR). An even higher molecular weight fraction (hereinafter, "ultra high molecular weight glue") dramatically influences foam collapse in both molded foam and laminated foam of both conventional and high resilience varieties (HR).

Up to now, a completely effective method for 'preventing the production of high molecular weight tail during propoxylation using DMC complex catalysts has not been known in the art. The use of processes such as the continuous addition of the initiator in both the intermittent and continuous polyol preparation, as disclosed in WO 97/29146 and U.S. Pat. DO NOT. 5,689,012, have partially proven effectiveness in decreasing the amount of high molecular weight tail in some cases. However, the portion that remains is still larger than the optimum if the polyether polyol is used for the preparation of the polyurethane foam. Commercially acceptable methods for removing or destroying high molecular weight glue have not also been developed. The destruction of high molecular weight species by means of peroxide-induced cleavage is ineffective, but also cleaving the desired molecular weight species as well. Fractionation with supercritical C02 is effective with some polyols but not with others, and is also very expensive to be commercially acceptable.

It has been observed that double metal cyanide complex catalysts containing high levels of free hydroxyl zinc ("Zn-OH") groups (unbound) tend to be the catalysts that produce polyether polyols having high amounts of high molecular weight tail impurity. Without wishing to be determined by theory, it is considered that the zinc hydroxyl group is in some cases involved in the formation of such impurities.

Inexplicably it has been found that the problem of reducing the high molecular weight tail in a polyether polyol obtained by using a double metal cyanide complex catalyst actually solved by contact with a silylating agent for a time and at an effective temperature to introduce the silyl groups within the catalyst.

The silylating agent can be an organic substance capable of acting as a source of silyl groups and is generally characterized as having at least one substituent capable of being replaced by a reactive component of the double metal cyanide complex catalyst such as, for example, example, free zinc hydroxyl groups. Without wishing to be determined by theory, it is believed that the improvements in catalyst performance made by the application of the present invention are at least in part due to the reaction of the silylating agent with the zinc hydroxyl groups or other damaged sites. initially present in the catalyst. That is, it has been observed that when the catalyst was treated with the silylating agent, the infrared absorption bands assigned to the free (non-associated) Zn-OH are largely eliminated, possibly due to the conversion of such groups to Zn-0 groups. -Si- (R) 3 (where the silylating agent has the structure X-Si- (R) 3, for example).

Suitable silylating agents include organosilanes, organosilylamines and organosilazanes. A generally preferred class of silylating agents are tetrasubstituted silanes having from 1 to 3 hydrocarbyl substituents, such as, for example, trimethyl chlorosilane, dichlorodimethylsilane, chlorobromodimethylsilane, nitrotrimethylsilane, chlorotriethylsilane, iododimethylbutylsilane, chlorodimethylphenylsilane, -ethoxytrimethylsilane, methoxytrimethylsilane, chlorotriphenylsilane, chlorotripropyl silane, chlorotrihexysilane, and the like. Very suitable silylating agents of the class comprising tetrasubstituted silanes wherein at least one substitute is halogen (eg, F, Cl, Br, I) or alkoxide (eg OR where R is preferably a hydrocarbyl C group? -C) and at least one substitute is a hydrocarbyl group preferably containing 1 to 4 carbon atoms. Particularly the preferred silylating agents of this type correspond to the formula (X) a-Si- (R) b where X is a halogen or alkoxide (for example C alco-C alkoxide), the R groups are the same or different and are selected from alkyl (e.g., C?-C4 alkyl), aryl (e.g., phenyl), or alkyl aryl groups (e.g., tolyl, benzyl), a is 1 or 2, b is 2 or 3, and a + b is 4.

Another suitable class of silylating agents are organosilazanes, particularly organodisilazanes. These molecules can be represented by the formula: H (R) 3-Si-N-Si- (R) 3 where the six R groups are the same or different and are organic groups or hydrogen. Preferably, the organosilazane containing R groups that are independently H or alkyl groups of up to 8 carbon atoms. The organosilizanos are generally symmetrical due to its production method, but can also be asymmetric. Suitable organosilizeans include, for example, 1,2-diethyldisilazane, 1,1,2,2-disilizane, -tetramethyl, disilazane of 1, 1, 2, 2, 2, -hexamethyl, and disilazane of 1, 2. -diisopropyl.

Other suitable silylating agent classes correspond to the formula X-Si- (R) 3 where the R groups are the same or different and are independently selected from hydrogen, alkyl, aryl or alkaryl and X is selected from O YCN -SMR1 ^ or an imidazolyl group, where Y is a group of alkyl or halogenated alkyl such as methyl or trifluoromethyl and R1 has the same meaning as R. A suitable silylating agent of this type is acetamide bis (trimethyl silyl). To effect improved silylation, the double metal cyanide complex catalyst was contacted with a suitable silylating agent as defined herein at an effective temperature to effect the reaction of the silylating agent with the catalyst. Excessively high temperatures, however, should be avoided because of the possibility that the catalyst may undergo chemical and / or physical transformations at such temperatures where the performance of the catalyst (such as, for example, activity) is adversely affected. to an unacceptable point. Although the optimum temperature must vary depending on the silylating agent selected, the contact conditions (for example, the liquid vs. the vapor phase), and the composition of the catalyst, temperatures of the range from 20 ° C to 125 ° C are generally spoken. that should be satisfactory.

The desired contact can be made in a variety of ways. For example, the catalyst (which should generally be in the form of a particulate) must be mixed with the silylating agent in a liquid phase. The liquid phase may contain a suitable non-reactive solvent such as an ether, hydrocarbon or the like, in addition to the silylating agent. After the desired contact time elapsed, some remaining liquid phase can be removed from the silylated catalyst by means of "conventional methods such as filtration, decantation, and / or evaporation." Alternatively, catalyst particles can be placed in Contact with a stream of the silylating agent in the vapor phase Silylation can be carried out as an intermittent, semi-continuous or continuous process.

The length of time required by the silylating agent to react with the catalyst of the double metal cyanide complex depends in part on the temperature and the agent employed. Low temperatures, for example, generally require long reaction times. Highly reactive silylating agents generally do not require reaction times as long as the less reactive silylating agents. However typically, contact times of from 0.1 to 48 hours must be sufficient.

The amount of silylating agent used can vary widely. Silylating agent amounts of from 0.1% by weight to 100% by weight, based on the weight of the double metal cyanide complex catalyst, are generally preferred. Any excess of the non-reactive silylating agent can, of course, be separated from the -catalyst after silylation and recycling. The silylating agent can be applied to the catalyst either in a treatment or in a series of treatments.

Generally, a single treatment is preferred for reasons of economy of operation.

The optimum amount of the silylating agent incorporated with the catalyst varies depending on a number of factors, including, for example, the composition and other characteristics of the initiating double metal cyanide complex catalyst. Sufficient silyl groups should be introduced so that the result in the catalyst of a silyl group that produces a low proportion of high molecular weight tail when used to catalyze the production of a polyether polyol which is the same catalyst before silylation Typically, Si levels in the catalyst after silylation vary from 0.1% by weight to 20% by weight. In some cases, however, even low levels may be sufficient to effect an improvement in catalyst performance.

The double metal cyanide complex catalysts treated with the silylating agent are substantially amorphous preferentially (in this context, meaning that no intensely pointed peaks are visible in an x-ray diffraction pattern) and are comprised of a double metal cyanide. , an organic complex agent and a metal salt. Such catalysts generally have a very high polymerization activity. For example, they are typically capable of polymerizing the propylene oxide in a proportion in excess of 3 grams (more preferably, 5 grams) of propylene oxide per minute per 250 ppm of catalyst (based on the combined weight of the initiator and the propylene) at 105 ° C. The double metal cyanide complex catalysts meet these requirements and the methods for their preparation are described in detail in U.S. Pat. Nos. 5,470,813, 5,482,908, 5,545,601, and 5,712,216, each of which was incorporated herein for reference in its entirety. Other double metal cyanide complex catalysts known in the epoxidation art can also be silylated according to the present invention.

The double metal cyanide is most preferably zinc hexacyanocobaltate, while the metal salt (used in excess in the reaction to form the double metal cyanide) is preferably selected from the group consisting of zinc halides ( zinc is especially preferred), zinc sulfate and zinc nitrate. The organic complex agent is desirably selected from the group consisting of alcohols, ethers and mixtures thereof, with water-soluble aliphatic alcohols such as tert-butyl alcohol is particularly preferred. The double metal cyanide complex catalyst is desirably modified with a polyether, as described in U.S. Patent Nos. 5,482,908 and 5,545,601.

The concentration of the silylated catalyst when used in an epoxide polymerization process is generally selected under such conditions that sufficient catalyst is present to polymerize the epoxide in a desired ratio or within a desired period of time. It is desirable to minimize the amount of the catalyst employed, both for economic reasons and to avoid having to remove the catalyst from the polyether polyol produced. The activities of the catalysts obtained by the practice of this invention are extremely high; Catalyst concentrations in the range of 5 to 50 parts per million based on the combined weight of the initiator containing the active hydrogen and the epoxide in this manner are typically sufficient.

The catalysts obtained by the practice of this invention are particularly useful for polymerizing propylene oxide wherein the homopolymerization of propylene oxide is particularly suitable for forming highly undesirable levels of high molecular weight glues. However, the process can also be employed to polymerize other epoxides such as ethylene oxide, 1-butene oxide and the like, either alone or in combination with other epoxides. For example, the copolymers of ethylene oxide and propylene oxide can be produced.

The initiator containing the active hydrogen may be any of the substances known in the art to be capable of performing the alkoxylation by means of the epoxide using a double metal cyanide complex catalyst and is selected based on the desired functionality and molecular weight of the polyether polyol product. Typically, the initiator (which may also be referred to as "initiator") must be oligomeric in character and have a number average molecular weight in the range of 100 to 1000 and a functionality (the number of active hydrogens per molecule) of starting from 2 to 8. Alcohols (e.g., organic compounds containing one or more hydroxide groups) are particularly preferred for use as initiators.

The polymerization can be conducted using any of the alkoxylation processes known in the art of the double metal cyanide complex catalyst. For example, a conventional intermittent process can be employed where the silylated catalyst and an initiator are introduced into an intermittent reactor. The reactor is then heated to the desired temperature (for example, from 70 to 150 ° C.) And an initial portion of epoxide is introduced. Once the catalyst has been activated, as indicated by a pressure drop and the consumption of the initial charge of the epoxide, the rest of the epoxide is added incrementally with a good mixing of the contents of the reactor and reacts until the desired molecular weight of the polyether polyol product. The initiators, monomers and polymerization conditions described in US Pat. No. 3,829,505 (incorporated herein by reference in their entirety) can be easily adapted for use in the present process.

Alternatively, a conventional continuous process can be employed as an initiator / catalyst mixture-previously activated continuously fed into a continuous reactor such as a continuously stirred tank reactor (CSTR) or tubular reactor. An epoxide feed was introduced into the reactor and the product was continuously removed. The process of this invention can also be easily adapted for use in continuous addition of processes of the initiator (initiator) either in an intermittent or continuous operation, such as those described in detail in WO 97/29146 (corresponding to the North American Application Application). Serial No. 08 / 597,781, filed on February 7, 1996, now in U.S. Patent No. 5,777,177), and U.S. Patent Serial No. 5,689,012, both are incorporated herein by reference in their totalities.

The polyether polyols produced by the operation of the process of the invention preferably have functionalities, molecular weights and suitable hydroxyl numbers for use in the molded and laminated foams. The nominal functionalities generally vary from 2 to 8. In general, the average functionality of the polyether polyol is mixed in the range of about 2.5 to 4.0. The polyether polyol equivalent weights generally range from a little less than 1000 Da to approximately 5000 Da. The -installation is preferably 0.015 meq / g or less, and more preferably in the range of 0.002 to about 0.008 meq / g. The hydroxyl numbers preferably vary in the range of 10 to about 80. The mixtures can, of course, contain low functionality polyols as well as high, equivalent weight, and hydroxyl numbers.

The performance of polyether polyols can be evaluated by testing these polyether polyols in "The Stiffness Stiffness Test" (TFT) and "The Super Critical Foam Test" (SCFT). It has been found that polyether polyols that pass these tests well in commercial applications of laminated and molded foam, without excessive rigidity, without "foam collapse." The SCFT consists of preparing a polyurethane foam using a formulation that is expressly designed to magnify the differences in the behavior of the polyether polyol.

In SCFT, a foam prepared from a given polyether polyol was reported as "sealant" if the surface of the foam appears convex after blowing and was reported as collapsed if the surface of the foam is concave after blowing. The amount of collapse can be reported in a relatively quantitative way by means of calculating the percentage change in the cross-sectional area taken through the foam. The formulation of the foam 'is as follows; polyether polyol, 100 parts, water, 6.5 parts; Methyl chloride, 15 parts; Niax® A-l amine type catalyst, 0.10 parts; tin catalyst T-9, 0.34 parts; silicone surfactant L-550, 0.5 parts. The foam reacted with a mixture of 80/20 diisocyanate of 2,4 and 2,6-toluene at an Index of 110. The foam can be conveniently poured into a standard 1 cubic foot cake box, or a container of standard 1 gallon ice cream. In this formulation, conventionally prepared, for example, polyether polyols with a base having a high number of secondary hydroxyl that causes the foam to settle approximately 10-20%, generally 15% ± 3%, while the polycarbonates prepared from DMC catalysts containing high unacceptable levels of high molecular weight glue which cause the foam to collapse at about 35-70%.

While the SCFT was used to evaluate differences in foam stability, the Foam Stiffness Test (TFT) increases the differences in reactivity, as reflected by the porosity of the foam. In the foam stiffness test, the resin component consists of 100 parts of polyether polyol, 3.2 parts of water (reactive blowing agent), 0.165 parts amine catalyst C-183, 0.275 parts tin catalyst T-9 , and 0.7 parts of silicone surfactant L-620. the resin component reacted with toluene diisocyanate 80/20 at an Index of 105. The stiffness of the foam was evaluated by measuring the air flow in the conventional manner. Narrow foams have reduced air flow.

The analytical procedure useful for measuring the amount of the high molecular weight tail in a polyether polyol catalyzed with the given DMC is a conventional HPLC technique, which can be easily performed by a person skilled in the art. The molecular weight of the high molecular weight fraction can be estimated by comparing its elution time in the GPC column with that of a standard polystyrene of appropriate molecular weight. As is well known, high molecular weight fractions are extracted from a GPC column more rapidly than low molecular weight fractions, and it helps in maintaining a baseline. It is appropriate, after elution of the high molecular weight fraction, to divert the remainder of the HPLC eluate to debris, instead of allowing it to pass through the detector, overloading the latter. Although many suitable detectors may be used, a convenient detector is a light evaporation scattering detector (ELSD) such as those commercially available.

In the preferred analysis method, a column of Jordi Gel DVB 103 Angstrom, 10x250mm, with particle sizes of 5 microns, was used with a mobile phase consisting of tetrahydrofuran. The detector used is a Varex Model IIA evaporation light scattering detector. The polystyrene reserve solutions are made from different molecular weights by means of an appropriate dilution with tetrahydrofuran, to form standards containing 2, 5, and 10 mg / L of polystyrene. Samples are prepared by weighing 0.1 grams of polyether polyol into a 1-ounce bottle, and adding tetrahydrofuran to the sample to bring the total weight of the sample and tetrahydrofuran to 10.0 grams. Samples of polystyrene calibration solutions from 2, 5 and 10 mg / L are sequentially injected into the GPC column. The duplicates of each sample solution of polyether polyol are then injected, after a reinjection of the various polystyrene standards. The maximum or peak areas for the polystyrene standards are electronically integrated, and the electronically integrated peaks for the two sets of each candidate polyol are electronically integrated and averaged. The calculation of the high molecular weight tail in ppm was then performed by standard data manipulation techniques.

Having generally described this invention, additional compression may be obtained by reference to certain specific examples that are provided herein for the purpose of illustrating only without attempting to be a limit unless otherwise specified.

EXAMPLES A substantially active non-crystalline double metal cyanide complex catalyst comprising hexacyanocobaltate, zinc chloride, tert-butyl alcohol and polyether polyol was prepared according to the procedures described in the U.S. application for U.S. No. 5,482,908. The desired quality of the silylating agent (trimethyl chlorosilane or trimethyl ethoxysilane) was dissolved in 30 ml of tert-butyl methyl ether. After mixing for 15 minutes, 6 grams of the double metal cyanide complex catalyst was added and the resulting mixture was heated at 55 ° C for 2 hours. The silylated catalyst was subsequently dried under vacuum using a rotary evaporator for 2 hours before being used in the polymerization of the epoxide.

The catalytic performances of three catalysts prepared using varying portions of trimethyl chlorosilane / catalyst ee compared to that catalyst that was not silylated in the preparation of polyether triols of molecular weight of 6000. The catalyst (30 ppm in the final product), the initiator containing active hydrogen (glycerin of a propoxyl group having a number equal to KOH / g 240 mg), and an initial change of propylene oxide were heated and stirred in a reactor at 105 ° C until the activation of the catalyst has been achieved, as indicated by a drop in pressure. The rest of the propylene oxide was then added incrementally while maintaining a reaction temperature of 105 ° C.

The gel penetration chromatographic analysis of the obtained polyether triol products showed that the silylation of the catalyst effectively reduces the amount of unwanted high molecular weight tail formed during the polymerization (Table 1).

• Comparative • 1 > 100,000 molecular weight The catalyst yield of two silylated catalysts prepared using varying amounts of trimethyl ethoxysilane / catalyst was compared with that of the non-silylated catalyst in the preparation of the 3000 molecular weight triols. The epoxide polymerizations were carried out as described. described in the previous sample, except that the reaction temperature was 120 ° C.

As shown in Table II, treatment with trimethyl ethoxysilane effectively decreases the amount of high molecular weight impurities present in the final product of the polyether polyol.

Table II * Comparative 1 nd = none detected It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, the content of the following is claimed as property:

Claims (24)

1. - A complex catalyst or double metal, silylated cyanide.

2. - A silylated double metal cyanide complex catalyst according to claim 1, characterized in that it can be prepared by reacting a double metal cyanide complex catalyst with an organosilane, an organosilylamine, an organosilazane, or a mixture thereof.

3. - A silylated double metal cyanide complex catalyst according to claim 1 or 2, characterized in that the organosilane has the formula: (X) a-Si- (R) b wherein: X represents a halogen atom, for example a chlorine atom, or an alkoxide group, for example an ethoxide group; R represents an unsubstituted or substituted alkyl, for example methyl, an aryl or alkaryl group; a is 1 or 2; b is 2 or 3; and a and b is 4, with the proviso that the groups R and (when a is greater than 1) the groups X may be the same or different.

4. - A silylated double metal cyanide complex catalyst according to claim 1 or 2, characterized in that the organosilylamine has the formula: X'-Si- (R ') 3 wherein: X' represents an imidazolyl group or a group of the formula: wherein Y represents an unsubstituted or halo-substituted alkyl group and R 'may assume some of the values of R '; and R 'represents a hydrogen atom or a substituted or unsubstituted alkyl, for example methyl, an aryl or alkaryl group with the proviso that the R' groups may be the same or different.

5. - A silylated double metal cyanide complex catalyst according to claim 1 or 2, characterized in that the organosilazane has the formula: H wherein: R "represents a hydrogen atom or an organisa group, organic, monovalent, substituted or unsubstituted, for example methyl, with the proviso that the R "groups may be the same or different.

6. - A silylated double metal cyanide complex catalyst / according to any of the preceding claims, characterized in that the double metal cyanide complex catalyst comprises zinc hexacyanocobaltate.

7. - A silylated double metal cyanide complex catalyst according to any of the preceding claims, characterized in that the double metal cyanide complex catalyst comprises a metal salt selected from the group consisting of zinc halides, for example zinc chloride, zinc sulfates, zinc nitrates and mixtures thereof.

8. - A silylated double metal cyanide complex catalyst according to any of the preceding claims, characterized in that the double metal cyanide complex catalyst does not have sharp peaks or sharp peaks in its X-ray diffraction pattern.

9. - A silylated double metal cyanide complex catalyst according to any of the preceding claims, characterized in that said double silylated metal cyanide complex catalyst comprises 0.1 to 20 weight percent Si.

10. A silylated double metal cyanide complex catalyst according to any of the preceding claims, characterized in that the double metal cyanide complex catalyst comprises a water-soluble aliphatic alcohol, for example tert-butyl alcohol.

11. - A silylated double metal cyanide complex catalyst according to any of the preceding claims, characterized in that the double metal cyanide complex catalyst comprises a polyether.

12. - A silylated double metal cyanide complex catalyst according to any of the preceding claims characterized in that it is preparable from the double metal cyanide complex catalyst comprising Zn-OH groups.

13. - A process for the preparation of a silylated double metal cyanide complex catalyst, characterized in that the process comprises contacting said double metal cyanide complex catalyst with a silylating agent to introduce silyl groups into said metal catalyst. double metal cyanide complex.

14. - A process according to claim 13, characterized in that at least 0.1 parts are used, suitably from 0.1 to 100 parts, by weight of the silylating agent per 100 parts by weight of the double metal cyanide complex catalyst.

15. - A process according to claims 13 or 14, characterized in that the reaction temperature is from 20 ° C to 125 ° C.

16. - A process according to any of claims 13, 14 or 15, characterized in that said contacting is carried out with a silylating agent present in a liquid phase or in a vapor phase.

17. - A process according to any of claims 13 to 16, characterized in that the reagents, or their amounts, are defined in any of claims 1 to 12.

18. - An epoxide polymerization process, characterized in that it comprises reacting an epoxide and an initiator containing active hydrogen in the presence of a silylated double metal cyanide complex catalyst according to any of claims 1 to 12 or prepared by means of the process of any of claims 13 to 17.

19. - An epoxide polymerization process according to claim 18, characterized in that the epoxide is selected from the group consisting of propylene oxide, ethylene oxide and mixtures thereof.

20. - A polymerization process according to claim 18 or 19, characterized in that the silylated double metal cyanide complex catalyst is present in a concentration of from 5 to 50 parts per million based on the combined weight of the initiator containing hydrogen and epoxide.

21. - An epoxide polymerization process according to claims 18, 19 or 20, characterized in that the initiator comprises an alcohol and the reaction is carried out at a temperature from 40 ° C to 150 ° C to form a polyether polyol.

22. - A polyether polyol preparable by means of the process of any of claims 19 to 21, characterized in that it contains not more than 500 ppm of polyol of molecular weight larger than 1000,000 Da.

23. - A polyether polyol according to claim 22, characterized in that it has: "an equivalent weight from 500 to 5000:" a functionality from 2 to 8; and "an unsaturation not greater than 0.015 meq / g.

24. - The use of a polyether polyol prepared with a silylated double metal cyanide complex catalyst in the production of the laminated polyurethane foam.