MXPA98003197A - Polymers polymers and stabilizer systems preform - Google Patents

Abstract

The present invention relates to: A preformed stabilizer composition based on a precursor stabilizer which is obtained by the reaction of a compound containing a silicon atom of the formula: RnSiX4no RnSi ((-) Si (R1) 2) p X) 4-n, in which the R groups are unsaturated or independently saturated hydrocarbyl groups, at least one R group is an olefinically unsaturated hydrocarbyl group, R1 is a hydrocarbyl group, X is a C1 to C10 alloxy group, n is an integrator of between 1 and 3 and p is an integrator greater than zero, with a polyether polyol having an average molecular weight of more than 400 and a hydroxyl number ranging from 20 to 280. It is used to make polyol polymer compositions that have a combination of (a) high polymer content, between 30 and 60 weight percent, (b) low viscosity levels, usually less than 9,000 centipoise, (c) product stability such that 100 percent passes through of network 150 and (d) Up to 100 percent of the solids content passes through the network 7

Description

POLYMERS POLYMERS AND PREFORMED STABILIZER SYSTEMS The present invention relates to the polymer polyols and to the process for preparing them, and to a preformed stabilizer used for the preparation of the polymer polyols. Polymer polyols suitable for the preparation of polyurethane foams and elastomers are well known and are widely used on a commercial scale. Polyurethane foams made from polymer polyols have a wide variety of uses. The two most important types of polyurethane foams are "slabstock" foam and molded foam. The first are used in carpets, furniture and effects for beds. The second, in the automotive industry in a wide variety of applications and uses. The polymer polyols are made by polymerizing one or more unsaturated ethylenically dissolved or dispersed monomers in a polyol in the presence of a free radical catalyst to form a stable dispersion of polymer particles in the polyol. In principle, polymer polyols that produce polyurethane foams with higher load bearing properties than those produced by unmodified polyols were prepared using an acrylonitrile monomer; however, many of these polymer polyols exhibited too high a viscosity level. Currently, polyurethane foams possessing high filler properties are predominantly produced using polymer polyols which are prepared with a monomer mixture with a high styrene content (eg, 65 to 75 percent styrene). However, the polymer polyols produced from such a mixture often do not meet the increasing demands of the industry, including an acceptable level of viscosity, strict stability requirements and higher loading properties. The stability and the low level of viscosity of the polymer podols are important factors for the manufacturers of polyurethane foam due to the development of sophisticated equipment, high speed and large volume as well as systems to handle, mix and form the ingredients of polyurethane. The polymer polyols must meet certain requirements in terms of particle size so that filters, pumps or other parts of the processing equipment do not clog or deteriorate in a relatively short time. Attempts have been made to produce polymer polyols that meet the high loading and processing requirements for the polyurethane foam industry. U.S. Patent No. 4242249 (Van Cleve et al) discloses polymer polyols that are prepared by the use of certain preformed dispersants and stabilizers. These polymer polyols provide a level of stability satisfactory for industrial production and utilize at least (i) high amounts of styrene or other comonomer with acplonitplo, (n) high solids contents or (ni) the use of low molecular weight polyols The stabilizer and the concentration used can vary with respect to the system of monomers used in the preparation of polymer polyols The U.S. Pat. No. 4652 589 (Simroth et al) describes stabilizing precursors for polymer polyols. Stabilizer A is made by reacting a 34, 15 percent by weight hydroxyl number of ethylene oxide coated with polyoxypropylene triol with maleic anhydride and then with ethylene oxide. stabilizer A has a hydroxyl number of 32 , a saturation of 0.1 meg / g, said saturation being 30/70 maleate / fumarate Stabilizer B is made by the reaction of a starter pohol with a sorbitol of hydroxyl number 28, containing 10 percent ethylene oxide internal, with maleic anhydride, and then with propylene oxide. Stabilizer B has a hydroxyl number of 28 and an unsaturation of about 0.07 meg / g, the unsaturation being of the fumarate type. U.S. Patent No. 5 196476 (Simroth) describes ( a) a high power preformed stabilizer, (b) the use thereof in the manufacture of polymer polyols having a high solid content, low viscosity level and excellent level of stability in the product, and (c) a polyurethane made with said polymer polyol The preformed stabilizer is the free radical polymerization product of at least one ethylenically radically polymerizable unsaturated monomer and at least one polyhydric alcohol addition product consisting of a polyhydric alcohol residue and a residue of a compound whose unsaturation is of the maleic or fumaric type . U.S. Patent No. 5,364,906 (Critchfield et al.) Discloses a method for producing a stable and low viscosity polymer polyol through a modified seed method whose steps are: (1) to make a first reaction product by polymerization of a first feed in a first continuous reactor in the presence of an initiator; said feed comprises less than 50 weight percent of a total monomer ratio in at least 50 weight percent of a total base polyol ratio, optionally in the presence of a precursor stabilizer which is prepared by the reaction of a polyol with maleic anhydride; and (2) making a second reaction product by polymerizing a second feed in a continuous reactor in the presence of an initiator, said second feed being comprised of (a) the first reaction product, (b) at least 50 percent by weight of the total monomer ratio and (c) a remainder of the polyol base ratio.

European Patent No. 0 162 589 B1 (Cloctens et al.) Discloses a non-aqueous dispersion stabilizer which is the reaction product of a polyether polyol having an average molecular weight greater than 400 and a hydroxyl number ranging from 20 to 280 with a compound containing a silicon atom having at least one olefinically unsaturated functional group and at least one functional group attached to the silicon atom which reacts with the hydroxyl groups in the polyether polyol. While some progress has been made in terms of reducing the viscosity level and increasing the solids content of the polymer polyol, there is still a need for polymer polyols with better processing and loading properties as well as of an alternative method to elaborate them. The present invention focuses on a preformed stabilizer composition and the manufacture of polymer polyols possessing a combination of (a) high polymer content, from 30 to 60 weight percent, (b) low viscosity indexes, usually less than 9000 centipoise (c) product stability such that 100 percent passes through a 150 sieve network, and (d) up to 100 percent of the solids content Polymers passes through a sieve network 700. In one aspect, the present invention relates to a preformed stabilizer composition which is employed in the preparation of polymer polyols consisting of the reaction product of: (i) a polyol; (ii) a precursor stabilizer which is obtained by the reaction of a compound containing a silicon atom of the formula: R "S¡X4-n or RnSi ((-) Si (R1) 2) pX) 4-n wherein the R groups are unsaturated or independently saturated hydrocarbyl groups, at least one R group is an olefinically unsaturated hydrocarbyl group; R1 is a hydrocarbyl group, X is a C 1 to C 1 alkoxy group, n is an integrator of between 1 and 3 and p is an integrator greater than zero, with a polyether polyol having an average molecular weight greater than 400 and a hydroxyl number which ranges between 20 and 280; (iii) at least one ethylenically unsaturated monomer that is copolymerizable with the precursor stabilizer; and (iv) a free radical polymerization initiator. In another aspect, the present invention relates to a process for the preparation of a preformed stabilizing composition; said process consists of providing the aforementioned components (i), (ii), (iii) and (iv) in a reaction zone at a temperature sufficient to initiate the polymerization of free radical, and under sufficient pressure to maintain phases liquid only in the reaction zone, for a period of time sufficient to react the entire precursor stabilizer and recover a heterogeneous mixture containing the preformed stabilizing composition. In another aspect, the present invention relates to a polyol polymer composition having a polymer content of between 30 and 60 weight percent, based on the total weight, a viscosity in centipoise not exceeding 8000 and a product stability of such that 100 percent passes through a 150 mesh network and up to 100 percent passes through a sieve network 700 produced by the free radical polymerization of the composition consisting of: (a) a polyol; (b) the stabilizer composition mentioned above; (c) at least one ethylenically unsaturated monomer; (d) a free radical polymerization initiator; and optionally, (e) a chain transfer agent. In another aspect, the present invention relates to a process for the preparation of a polyol polymer composition; said process consists in providing the aforementioned polymer polyol which forms the components (a), (b), (c) and (d) in a reaction zone which are maintained at a temperature sufficient to initiate a free radical polymerization, and sufficient pressure to maintain only liquid phases in the reaction zone for a period of time sufficient to react a significant portion of the ethylenically unsaturated monomer to form a heterogeneous mixture containing the polymer polyol and recover said mixture. In another aspect, the present invention relates to a polymer polyol composition having a polymer content of between 30 and 60 weight percent, based on the total weight, a centipoise viscosity level of no more than 8000 and a stability of product so that essentially 100 percent passes through the screen network 150 produced by the free radical polymerization of the aforementioned polymer polyol.

In another aspect, the present invention relates to a composition forming a polyurethane foam consisting of the aforementioned poiyol composition, a polyurethane catalyst, an organic polyisocyanate, a silicone surfactant and a blowing agent. The precursor stabilizers which are useful in the present invention are obtained by the reaction of a compound containing a silicon atom of the formula: 1 \ 2, RnSiX4-n or RnSi ((-) Si (RT) P X) 4-n wherein the R groups are unsaturated or independently saturated hydrocarbyl groups, at least one R group is an olefinically unsaturated hydrocarbyl group; A hydrocarbyl group, X is a C 1 to C 1 alkoxy group, n is an integrator of between 1 and 3 and p is an integrator greater than zero, with a polyether polyol having an average molecular weight greater than 400 and a hydroxyl number which The preferred precursor stabilizers are the reaction products of vinyltrimethoxy silane, vinyltriethoxy silane or vinyltripropoxysilane with a polyether polyol whose average molecular weight exceeds 400 and its hydroxyl number ranges between 20 and 280. These precursor stabilizers and their preparation are described in European Patent No. 0 162 589 B1 (Cloctens et al). The polyols used in the composition for preparing the preformed stabilizer composition of the present invention may be, for example, polyether polyol, polyesters containing polyhydroxyl, polyurethane polymers terminated with polyhydroxy, polythioether polyurethane and polytetrahydrofuran. These polyols are well known and are available in the market. The preferred polyols are the polyether polyols. The polyether polyol used should have an average molecular weight greater than 400, preferably 3000, preferably 5000, and a hydroxyl number ranging from 20 to 280. More preferably, the polyether polyol should be a poly (oxytylene) addition product (oxypropylene) ) of an alcohol selected from glycerol, trimethylolpropane, diethylene glycol, the isomers of butanetriol, pentanotriol and hexanetriol and pentaerythritol, sucrose and sorbitol. A mixture of polyols can be used, if desired. The concentration of polyol in the reformed stabilizer that forms the composition is not of vital importance and can vary widely. In general, the concentration can vary between 50 and 90 weight percent, more preferably between 60 and 90 weight percent, preferably between 60 and 70 weight percent, based on the total feed in the reactor. If desired, a mixture of several polyols may be employed. As a component, an ethylenically unsaturated monomer which is free radical polymerizable (iii) can be employed in the preformed stabilizer forming the composition of the present invention. It is preferable to use vinyl monomers. Styrene, acrylonitrile, methacrylonitrile and methyl methacrylate are preferred vinyl monomers. Others, even more preferred are styrene, acrylonitrile and mixtures thereof. Generally, a minimum of between 2 and 20 weight percent of an ethylenically unsaturated monomer is used in the preformed stabilizer that forms the composition. When a mixture of styrene and acrylonitrile is employed, the weight ratio of the styrene can vary between 20 and 80 weight percent of the mixture. It is preferable to employ an ethylene / acrylonitrile ratio in the monomer mixture of between 80:20 and 20:80; the ideal relationship ranges between 70:30 and 50:50. The free radical polymerization initiator which is useful in the preparation of the preformed stabilizer of the present invention can be any compound that is conventionally employed to effect grafting of an ethylenically unsaturated polymer to a polyol including peroxides, perborates, persulfates, percarbonates and azo compounds. Typical examples of such initiators are alkyl and aryl hydroperoxides, dialkyl and diaryloperoxides, dialkylperoxydicarbonates and azobis (nitriles). Preferred free radical initiators are tert-butylperoxy diethyl acetate and tert-butyl peroctoate. The concentration of said initiator in the preformed stabilizer that forms the composition is not of vital importance and can vary widely. In general, the concentration can vary between 0.01 and 2.0 weight percent or more, preferably between 0.05 and 0.2 weight percent, based on the total feed in the reactor. The chosen concentration will be the optimal value considering all factors, including costs. Generally, the polyol is used in an amount of between 50 or less than 80 percent by weight, the precursor stabilizer in an amount ranging from 10 to less than 50 weight percent, the monomer in an amount of 5 to 15 weight percent and the polymerization initiator in an amount of between 0.01 and 2 weight percent in the preformed stabilizer forming the composition of the present invention. The process for making the preformed stabilizer is similar to the process for making the polyol polymer. The temperature range is not critical and can vary between 80 and 150 ° C. The ideal temperature variation is from 1 10 to 1 30 ° C. The mixing conditions used are those obtained by using a back-mixed reactor. The reactors keep the reaction mixture relatively homogeneous and in this way no localized ratios of high monomer to precursor stabilizer are observed which are observed in the tubular reactors, in which all the amount of monomers is added to the reactor at the beginning. The present invention also relates to the preparation of stable, high solids polyol polymer compositions having acceptable levels of viscosity. The polyol polymer composition of the invention has a polymer content of between 30, preferably 40, more preferably 40 to 50 weight percent, the remainder being liquid polyol. With respect to the solids content, it may have a centipoise viscosity of less than 9000. The polymer polyol compositions of the present invention also exhibit exceptional stability so that 100 percent passes through a 150 mesh and a significant amount of solids, essentially 100 percent, passes through a 700 sieve. As illustrated in the examples, the polyol polymer compositions possess a solids content of 42.2, 45.2, 40.6 and 41.8 percent with a viscosity of between 5550, 6800, 4950 and 3280 centipoise, respectively, all pass (essentially 100 percent) by a 700 mesh. The polyol polymer composition of the present invention is the reaction product of the composition which costs: a) a polyol, (b) the preformed stabilizer composition of the present invention; and (c) at least one ethylenically unsaturated monomer; and (d) a free radical polymerization initiator.

The process for making the polyols of the present invention consists of (1) having a homogeneous mixture of the preformed stabilizer composition of the present invention in combination with a polyol, at least one polymerizable monomer with a free radical and a polymerization initiator of free radical, in a reaction zone that is maintained at a temperature sufficient to initiate a free radical polymerization reaction, and under sufficient pressure to maintain only liquid phases in the reaction zone, for a time sufficient to react a high proportion of at least one ethylenically unsaturated monomer, and recovering the resulting polymer pohol In the preparation of the polymer polyols of the present invention, any polyol with a functionality of at least two and a molecular weight exceeding 400 can be used, preferably between 1000 and 15000, more preferably between 2000 and 8000, and a hydroxyl number ranging between 20 and 280 These polyols are well known and are commercially available The same or a different one from that used in the preparation of the preformed stabilizer can be used for the preparation of the polymer composition of the invention. Useful polymers can be mentioned, for example, polyether polyols, polyhydroxyl-containing polyesters, polyhydroxy-terminated polyurethanes and polytetrahydrofurans. Preferred polyols are polyether polyols. More preferably, polyether polyols should be a polymeric addition product. (ox? t? len) (oxypropylene) of an alcohol selected from glycerol, trimethylolpropane, diethylene glycol, the isomers of butanetriol, pentanotriol and hexanetriol and pentaerythritol. The concentration of the polyol in the polymer polyol that forms the composition is not of vital importance and can vary widely. In general, the concentration can vary between 40 and 80, preferably between 45 and 70, more preferably between 50 and 60 weight percent, on the total basis of the feed in the reactor. The polyol used will depend on the final use of the polyurethane foam that it is desired to produce. A mixture of the useful polyols can be used, if desired. As the component, an ethylenically unsaturated monomer which is free radical polymerizable (iii) can be employed in the preformed stabilizer which forms the composition of the present invention. It is preferable to use vinyl monomers. Styrene, acrylonitrile, methacrylonitrile and methyl methacrylate are preferred vinyl monomers. Others, even more preferred are styrene, acrylonitrile and mixtures thereof. Generally, a minimum of 30 to 60 weight percent of an ethylenically unsaturated monomer is used in the preformed stabilizer that forms the composition. When a mixture of styrene and acrylonitrile is used, the weight ratio of the styrene can vary between 80 and 20 weight percent of the mixture. It is preferable to employ a styrene / acrylonitrile ratio in the monomer mixture of between 80:20 and 20:80; the ideal relationship ranges between 70:30 and 50:50. The free radical polymerization initiator which is useful in the preparation of the preformed stabilizer of the present invention can be any compound that is conventionally employed to effect the vinyl polymerization reaction including peroxides, perborates, persulfates, percarbonates and azo compounds. Typical examples of such initiators are alkyl and aryl hydroperoxides, dialkyl and diaryl peroxides, dialkylperoxydicarbonates and azobis (nitriles). Preferred free radical initiators are 2,2-azobis (bearbutyronitrile) and 2,2-azobis (methylbutyronitrile). The concentration of said initiator is not of vital importance and can vary widely. In general, the concentration can vary between 0.01 and 2.0 percent by weight or more., preferably between 0.05 and 0.2 weight percent, based on the total feed in the reactor. The chosen concentration will be the optimum value considering all factors, including costs. If desired, any chain transfer agent can be employed in the composition of the preformed stabilizer of the present invention. Preferred agents are the mono or hydroxy alcohols because they can be easily separated from the polyol polymer composition. The ideal agent is isopropanol. The composition forming the polymer polyol is placed in the reactor, preferably in a continuous, stirred, back mixed reactor. The internal temperature of the reactor is controlled so that it oscillates between 80 and 150 ° C, preferably between 110 and 130 ° C The content of the reactor is mixed well with a residence time of at least 5 minutes, preferably between 15 and 45 minutes . The polyol polymer composition of the present invention is useful for the manufacture of polyurethane foams. Said foams possess improved properties of load bearing and tensile strength without thereby affecting other physical characteristics of the foam. The polyurethane foams are made by reacting a polyol polymer composition of the present invention with a polyfunctional organic isocyanate in the presence of a catalyst for the urethane-forming reaction, a blowing agent and a foam stabilizer. The polyfunctional organic isocyanates that can be used in the manufacture of polyurethane foam are well known to those familiar with the art, and are available commercially. Illustrative examples of useful polyfunctional organic isocyanates include toluene diisocyanates, especially 2,4- and 2,6-toluene diisocyanate (TD!) As well as the mixture of these isomers; 2,4'- and 4,4'-diphenylmethane-diisocyanate) MDI), as well as the mixture of these isomers; MDI oligomers (polymeric MDI, polyphenyl polymethylene polyisocyanates (commonly called "crude MDI"), polymeric TDI and MDI mixtures and mixtures of these polyisocyanates The aforementioned isocyanate prepolymers (for example, with polyether polyols, glyols and mixtures of these ) can also be used in the invention The preferred isocyanate is 80/20 TDI (a mixture of 80 percent 2,4-toluene diisocyanate and 20 percent 2,6-toluene diisocyanate) Polyfunctional isocyanates are used in conventional amounts. employing any conventional blowing agent used in the manufacture of polyurethane foams Suitable water blowing agents include water and halogenated hydrocarbons of low molecular weight.The blowing agents are used in conventional amounts. any of the polyurethane catalysts normally used in the preparation of polyurethane foams in the process of the present invention, including tertiary amines and organometallic compounds. The polyurethane catalyst is used in conventional amounts. Also, mixtures of polyurethane catalysts can be used in the process of the present invention. In the present invention, any of the foam stabilizers or surfactants may be used to achieve the stability of the cell or other size control agents thereof normally employed in the preparation of polyurethane foams. Foam stabilizers, surfactants to achieve cell stability or other control agents are used in conventional amounts. Also, mixtures of one or more stabilizers and / or one or more its surfactants may be employed. Among suitable surfactants are those of silicon, preferably those which are block copolymers of a polysiloxane and a polyoxyalkylene as described in U.S. Patent No. 3,629,308. Also, conventional crosslinkers can be used in the process of the invention in order to modify the properties of the polyurethane foam. These crosslinking agents are used in conventional amounts. In addition to the aforementioned materials, any additive conventionally used in the manufacture of polyurethane foams can be used, such as, for example, flame retardants, defoamers, antioxidants, mold release agents, dyes, pigments and sealants. These additives are used in conventional amounts. The following names, symbols, terms and abbreviations are used in the Examples that appear later: CP-3040: is a polyol initiated with glycerin that has a hydroxyl number that ranges between 54 and 59 and an average molecular weight of 3000 and a level of viscosity at 25 ° C of 490 cps, is marketed by The Dow Chemical Company under the trademark VORANOL CP-3040. CP-4702: is a polyol initiated with glycerin having a hydroxyl number ranging between 33 and 38 and an average molecular weight of 4700 and a viscosity level at 25 ° C of 820 cps, is marketed by The Dow Chemical Company with the brand VORANOL CP-4702.

DNC-635.04: is a polyol initiated with itol having a hydroxyl number of 30 and an average molecular weight of 7000. VTMSP: precurmodified by vinyltrimethoxy silane which is prepared according to Example 3 of EP-O 162 589 B1. Trigonox 27: is a free radical polymerization initiator marketed by Akzo Chemie under the trademark TRIGONOX 27. VazoR 67: is a 2,2'-Azobis polymerization catalyst (2-methylbutanonitrile) prepared by E. I. duPont de Nemours and Co.

DABCO 33LV: is a 33% solution of triethylene diamine and dipropylene glycol, marketed by Air Products and Chemicals Inc. with the trade name DABO 33LV. NIAX A-107: is a version blocked by formic acid of the catalyst of 70% bis (22-dimethylaminoethyl) ether and 30% of dipropylene glycol amine marketed by Union Carbide Corp. under the trade name NIAX A-107. DEOA: is Diethanolamine. DC-5164: is a silicone surfactant marketed by Dow Corning Corporation. IPA: is isopropanol. TDI-80: is an 80:20 mixture of the 2,4 and 2,6,6-toluene diisocyanate isomers marketed by The Dow Chemical Company under the tradename VORANATE T80. Index (index) is the ratio of the amount of reactive isocyanate groups in the reaction mixture, divided by the amount of active hydrogen groups in the reaction mixture multiplied by 100. STN: is styrene. ACN: it's acrylonitrile. The properties of the polyol polymer composition of the polyurethane foams that appear in the Examples below are determined according to the following test methods: Air circulation (cfm) is measured according to ISO 7231 test method (in an instrument of foam porosity AMSCOR). Density: measured according to test method DIN 53420.

CFD 40% (kPa): is the compression force reflection according to DIN 53577. IFD 25% (N): it is the deflection of force by indentation 25 per cent according to ASTM D-3574, Tests B1 and B2. IFD 40% (N): is the deflection of force by indentation at 40 percent determined in accordance with ASTM D-3574, Tests B1 and B2.

IFD 65% (N): is the deflection of force by indentation at 65% determined in accordance with ASTM D-3574, tests B1 and B2. SAG factor is the deflection of force by indentation divided by the deflection of force by indentation 25%. Tensile strength (kPa) is determined in accordance with ASTM D-3574 Elongation (%) • is determined in accordance with ASTM D-3574, Test E Tear strength (N / m) is determined in accordance with ASTM D-3574 Filtering capacity- ("Filterabi ty") is the Filtration Hindrance determined by diluting one part by weight of the sample (eg, 470g) of polymer with two parts by weight of anhydrous isopropanol (for example, 960g) to eliminate any limitations imposed by the viscosity and to use a fixed amount of material in relation to the cross-sectional area of the screen, so that the total of the polymer polyol and the isopropanol solution passes through a network 150 or 700 The first has a square network with an average aperture of 105 microns and is a "Standard Tyler" The second is made with a Dutch cross hatching The screen that was used had a nominal opening of 30 microns The amount of sample that passes through the screen in 3000 seconds recorded as a percentage, a value of 100 percent indicates that more than 99 percent by weight passed through or the Viscosity screen is measured using a Brookfield viscometer, spindle (measuring instrument) # LVVT3, speed 12, according to ASTM D-4874 The following examples serve to illustrate the invention and should not be considered as limiting Unless otherwise indicated, all parts and percentages are expressed by weight Examples 1 and 2: Preparation of the preformed stabilizer The preformed stabilizer was prepared in a continuous polymerization reactor using a tank reactor equipped with partitions and propellant. The contents were pumped continuously after going through an in-line mixer to ensure the correct mixing of the components before entering the reactor. The content of the reactor was mixed well. It was controlled that the temperature inside the reactor was 1 ° C. The product flowed out of the reactor and entered the second non-agitated reactor where the temperature was also 1 ° C. Then, the product flowed out of the second reactor continuously through a back pressure regulator that had been adjusted to maintain a pressure of 65 psig in both reactors. Then, the preformed stabilizer flowed through a cooler to a container. The corresponding compositions appear in Table I below: TABLE Examples 3 to 9: Preparation of the Polyol Polymer Composition The polyol polymer of the present invention was prepared using a continuous polymerization system, using a tank reactor equipped with partitions and propellant. In Examples 3 and 4 and 6 to 9 the components of the feed composition were pumped into the reactor continuously after passing through an in-line mixer to ensure the correct mixing of the components before entering the reactor. The content of the reactor was mixed well. It was controlled that the temperature inside the reactor was 1 ° C. The product flowed out of the reactor and entered the second non-agitated reactor where the temperature was also 1 ° C. Then, the product flowed out of the second reactor continuously through a back pressure regulator that had been adjusted to maintain a pressure of 45 psig in both reactors. The crude polymer polyol product then flowed through a cooler and into a vessel. The percentage by weight of polymer in the polyol was determined from the analysis of monomers that did not react in the crude product. The crude product was removed in vacuo to remove volatile before the test. The polymer polyol of Example 5 was prepared by extending the same procedure as in Examples 3 and 4 and 6 to 9, with the exception that the reactor was fed continuously with the preformed stabilizer from the reactor where it was prepared, while the rest of the composition was pumped into the same reactor. All the polyols produced were stable compositions. The feed compositions, the conditions of preparation and the properties of the polymer polyol appear in Table II. Table II: Examples 10 to 11: Preparation of polyurethane foams Polyurethane foams were made by pouring the foam formulations shown in Table III into an aluminum mold, 16 liter capacity (40x40x10cm), and four heated vent holes. a temperature of about 60 ° C using an Admiral DHF-I high pressure pouring machine and a Krauss Maffei MK12-12 / 16-UL-2K Duplex mixing head so that the foam rose and cured. The demolding time of the foam was 5 minutes. A demolding agent Klüber 918 / 9K (marketed by Klüber AG) was used. The pressure of the tanks of the polyol / isocyanate components was 3 bars. Both components were dispensed at approximately 150 pressure bars. The polymer polyol A used in the foam formulation detailed in Table III was the polyol produced in Example 3 hereof, diluted with a base polyol CP-4702. The polymer polyol A has a viscosity (at 25 ° C) of 3000 cps and a solids content of 28 weight percent. The polymer polyol B used in the foam formulation shown in Table III was that produced in Example 3 hereof, diluted with CP-4702 base polyol. The polymer polyol B had a viscosity (at 25 ° C) of 3400 cps and a solids content of 33 weight percent. The foam formulations and the properties of the foam appear in Table III. As can be seen in Table III, the polyurethane foams prepared in Examples 10 and 11 using the polymer polyol of the present invention exhibited high load bearing characteristics without significant loss of other physical characteristics. Table III

Claims (15)

1. - A preformed stabilizer composition for use in the preparation of copolymer polyols consisting of the reaction product of: (i) a polyol; (i) a precursor stabilizer which is obtained by the reaction of a compound containing a silicon atom of the formula: R "SiX4." Or R "Yes ((-) Si (R1) 2) p X) 4-p wherein the R groups are unsaturated or independently saturated hydrocarbyl groups, at least one R group is an olefinically unsaturated hydrocarbyl group; R1 is a hydrocarbyl group, X is a C 1 to C 1 alkoxy group, n is an integrator of between 1 and 3 and p is an integrator greater than zero, with a polyether polyol having an average molecular weight greater than 400 and a hydroxyl number which ranges between 20 and 280; (iii) at least one ethylenically unsaturated monomer that is copolymerizable with the precursor stabilizer; and (iv) a free radical polymerization initiator.

2 - A preformed stabilizer composition according to claim 1, wherein the precursor stabilizer is obtained by the reaction of vinyltrimethoxy silane, vinyltriethoxy silane or vinyltripropoxysilane with a polyether polyol whose average molecular weight exceeds 400, its hydroxyl number ranges from 20 to

280.

3. A preformed stabilizer composition according to claim 1 or 2 wherein the polyol is a polyether polyol whose average molecular weight exceeds 400 and its hydroxyl number ranges between 20 and 280.

4.- A preformed stabilizer composition according to with claims 1 to 3, wherein at least one ethylenically unsaturated monomer is a mixture of acrylonitrile and styrene.

5. A process for the preparation of the preformed stabilizing composition; said process consists of obtaining a composition consisting of: (i) a polyol; (ii) a precursor stabilizer which is obtained by the reaction of a compound containing a silicon atom of the formula: RpSiX4.n or R "Si ((-) Si (R1) 2) p X) 4.n wherein the R groups are unsaturated or independently saturated hydrocarbyl groups, at least one R group is an olefinically unsaturated hydrocarbyl group; R1 is a hydrocarbyl group, X is a C. to Cio alloy group, n is an integrator of between 1 and 3 and p is an integrator greater than zero, with a polyether polyol having an average molecular weight greater than 400 and a hydroxyl number which ranges between 20 and 280; (iii) at least one ethylenically unsaturated monomer that is copolymerizable with the precursor stabilizer; and (iv) a free radical polymerization initiator. and in a reaction zone that is maintained at a temperature sufficient to initiate free radical polymerization, and sufficient pressure to maintain only liquid phases in the reaction zone, for a sufficient period of time to substantially react the entire stabilizer precursor and recover the preformed stabilizing composition.

6 - A process according to claim 5, wherein the reaction zone is maintained at a temperature ranging between 80 and 150 ° C.

7. A polyol polymer composition having a polymer content ranging from 0 to 60 weight percent, based on the total weight, a centipoise viscosity not exceeding 9000 and a product stability such that essentially 100 percent it passes through the 150 mesh and up to 100 percent passes through the 700 mesh produced by the free radical polymerization of the composition consisting of: (a) a polyol; (b) the preformed stabilizer according to any of claims 1 to 4; (c) at least one ethylenically unsaturated monomer; (d) a free radical polymerization initiator; and optionally, (e) a phase transfer agent.

8. - A polyol polymer composition according to claim 7, in which the preformed stabilizer is prepared by the process of claim 5.

9. A polyol polymer composition according to claim 7 or 8., wherein at least one ethylenically unsaturated monomer is a mixture of acrylonitrile and styrene.

10. A polyol polymer composition according to claim 9, wherein the acrylonitrile and the styrene are present in the mixture in a ratio of between 20:80 and 80:20.

11 - A process for the preparation of a polyol polymer composition, said process consists in providing a composition consisting of: (a) a polyol; (b) the preformed stabilizer according to any of claims 1 to 4; (c) at least one ethylenically unsaturated monomer; (d) a free radical polymerization initiator, and optionally, (e) a phase transfer agent. in a reaction zone which is maintained at a temperature sufficient to initiate polymerization of the free radical, and sufficient pressure to maintain only liquid phases in the reaction zone, for a sufficient period of time to substantially react most of the at least one monomer not ethylenically saturated and recovering the polymer pohol.

12 - A process according to claim 11, wherein the reaction zone is maintained at a temperature of 80 to 150 ° C.

13. A composition for the preparation of a polyurethane foam in which polymer polyol, a polyurethane catalyst, an organic polyisocyanate, a surfactant and a blowing agent are used, characterized in that the polymer polyol consists of polyol polymer of according to claim 7 to 10.

14. A polyurethane foam prepared from a composition according to claim 13.

15. A polyurethane foam prepared from a polyol polymer composition according to claim 7 a 10