GB1598930A - Preformed copolymeric stabilizers suitable for use in the preparation of polymer/polyol compositions - Google Patents

Description

PATENT SPECIFICATION ( 11) 1 598 930

( 21) Application No 42510/79 ( 22) Filed 19 Dec 1977 Co ( 62) Divided out of No1598929 ( 19) ( 31) Convention Application No 752818 00 ( 32) Filed 20 Dec 1976 in ( 33) United States of America (US) ( 44) Complete Specification published 23 Sept 1981 -I ( 51) INT CL 3 C 08 F 283/06 2/14//C 08 L 75/04 ( 52) Index at acceptance C 3 P 202 216 316 390 394 DI FC C 3 Y B 230 B 233 G 130 G 140 ( 54) PREFORMED COPOLYMERIC STABILIZERS SUITABLE FOR USE IN THE PREPARATION OF POLYMER/POLYOL COMPOSITIONS ( 71) We, UNION CARBIDE CORPORATION, a Corporation organised and existing under the laws of the State of New York, United States of America, of 270 Park Avenue, New York, State of New York, 10017, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in 5

and by the following statement:-

The present invention relates to processes for producing preformed copolymeric stabilizers suitable for use in the preparation of polymer/polyol compositions.

Polymer/polyol compositions suitable for use in producing polyurethane 10 foams, and elastomers are known materials The basic patents in this field are

United States Patents Nos 3,304,273, 3,383,351 and Reissue No 28,715 to Stamberger These compositions can be produced by polymerizing one or more olefinically unsaturated monomers dissolved or dispersed in a polyol in the presence of a free radical catalyst These polymer/polyol compositions have the 15 valuable property of imparting to, for example, polyurethane foams and elastomers produced therefrom, higher load-bearing properties than are provided by unmodified polyols.

In addition, United States Patent No 3,523,093 to Stamberger discloses a method for preparing polyurethanes by reacting a polyisocyanate with a mixture of 20 a polyol solvent medium and a preformed normally solid film-forming polymeric material obtained by polymerization of ethylenically unsaturated monomers The film-forming polymer may be prepared by various techniques, including polymerizing the monomers in the presence of reactive radical-containing compounds such as alcohols and mercaptans 25 The polymer/polyol compositions initially introduced were primarily compositions produced from polyols and acrylonitrile and, to some extent, acrylonitrilemethylmethacrylate mixtures These compositions were at least primarily used commercially in producing foams under conditions such that the heat generated during foaming is readily dissipated (e g -the foams are of a relatively thin cross 30 section) or under conditions such that relatively little heat is generated during foaming When the heat is not readily dissipated, the foams tend to scorch (discolor).

British Patent Specification No 1412797 (Priest) describes an improved process for forming polymer/polyols from acrylonitrile-styrene monomer systems 35 which includes, in general, maintaining a low monomer concentration throughout the reaction mixture during the process The polymer/polyols thus produced can be converted to low density, water-blown polyurethane foams having reduced scorch in comparison to all acrylonitrile, and acrylonitrile-methylmethacrylate polymer/polyols However, the stability of the polymer/polyols decreases with 40 increasing styrene to acrylonitrile ratios Further, the discoloration (scorch) of the resulting foams still presents some problems, particularly when the polymer composition contains a relatively high acrylonitrile to styrene ratio.

Still further, British Patent Application No 35430/75 (Serial No 1516385) (Simroth) discloses additional and substantial improvements in forming 45 polymer/polyols This allows the optimization of the polymer content and the usable monomer ratios for a given polyol.

British Patent Application No 28713/76, (Serial No 1559121) (Van Cleve et al) discloses further improvement in the formation of polymer/polyols As discussed therein, polymer/polyol compositions exhibiting outstanding properties can be 5 made by utilizing, in the formation of the polymer/polyols, a specific type of peroxide catalyst, namely t-alkyl peroxyester catalysts By the utilization of this specific type of catalyst, polymer/polyols can be produced on a commercial basis with outstanding properties such as filterability in processing yet which allow either the polymer or the styrene content to be increased Also, polymer/polyols can be 10 roduced on a commercial scale with polyols having a molecular weight lower than gave been used prior to this invention.

Despite these improvements, there is still room for further refinement Thus, in the slabstock foam area, the problem of scorch presents a barrier to the use of acrylonitrile-containing polymer/polyols where the buns have a relatively large 15 cross-section It would be desirable to be, in effect, capable of providing acrylonitrile copolymer polymer/polyols that would be sufficiently low in acrylonitrile content to provide reliable assurance that the resulting buns would be even less subject to scorch Achievement of this objective requires the utilization of relatively high levels of styrene or other comonomers, so that the acrylonitrile 20 content is about 30 to 40 percent of the monomer system used or even lower While these polymer/polyols can be produced with certain limitations by prior techniques, the production is not as commercially trouble-free as is desired.

More particularly, the production of polymer/polyols on a large commercial scale with the economy needed places practical limitations on the minimum ratio 25 of acrylonitrile to styrene or other comonomer used in the monomer system, the minimum polyol molecular weight and the maximum polymer content when prior techniques are employed Commercial production thus requires that the resulting polymer/polyols have relatively low viscosities so that processing in the production equipment can be economically carried out Further, the stability resulting must be 30 sufficient to allow operation without plugging or fouling of the reactors as well as allowing for relatively long term storage.

The polymer/polyols must also be capable of being processed in the sophisticated foam equipment presently being used Typically, the prime requirement is that the polymer/polyols possess sufficiently small particles so that 35 filters and pumps do not become plugged or fouled in relatively short periods of time.

While somewhat simplified, the commercial processability of a particular polymer/polyol comes down to its viscosity and stability against phase separation.

Lower viscosities are of substantial practical and economic significance due to the 40 ease of pumping and metering as well as ease of mixing during the formation of polyurethanes Stability is of prime consideration in ensuring that the polymer/polyols can be processed in commercial production equipment without the necessity of additional mixing to ensure homogeneity.

It has been recognized that the stability of polymer/polyols requires the 45 presence of a minor amount of a graft or addition copolymer which is formed in situ from the polymer and polyol.

With regard to graft copolymer stabilizers, a number of literature references have observed large differences in grafting efficiency between the use of peroxides such as benzoyl peroxide and azobis-isobutyronitrile in certain monomerpolymer 50 systems In general, the conceptual thrust is that the use of peroxide catalysts should improve the stability inasmuch as this type of catalyst produces a relatively greater amount of the graft specie.

Others have noted no marked differences in grafting efficiency In the Journal of Cellular Plastics, March, 1966, entitled "Polymer/Polyols; A New Class of 55 Polyurethane Intermediates" by Kuryla et al, there is reported a series of precipitation experiments run to determine any marked differences in the polymer/polyols produced by either benzoyl peroxide or azobisisobutyronitrile when used as the initiators in the in situ polymerization of acrylonitrile in a propylene oxide triol having a theoretical number average molecular weight of 60 about 3000 The data indicated no significant differences between the polymers isolated, and no marked "initiator effect" was observed.

With regard to addition copolymer stabilizers, efforts in the polymer/polyol field have been concerned with the incorporation of additional amounts of unsaturation to that inherently present in the polyoxyalkylene polyols typically 65 1,598,930 used in forming polymer/polyols United States Patents Nos 3,652,639 and 3,823,201 and British Patent Specification No 1,126,025 all utilize this approach.

None of the above patents recognize the utility of adding a tailored, preformed stabilizer in producing polymer/polyols.

In general, a substantial amount of additional effort has been directed towards 5 dispersion polymerization in organic liquids This involves the polymerization of a monomer dissolved in organic liquid to produce insoluble polymer dispersed in the liquid as a continuous phase in the presence of an amphipathic graft or block copolymer as the dispersant (stabilizer) According to a recent text, "Dispersion Polymerization in Organic Media", edited by K E G Barrett, John Wiley & Sons, 10 copyright 1975, the development of techniques for the preparation of dispersions of polymers of controlled particle size in organic liquids has been largely motivated by the requirements of the surface coatings industry The function of the dispersant or stabilizer in a sterically-stabilized colloidal dispersion is to provide a layer of material solvated by the dispersion medium on each particle surface Every particle 15 is thus surrounded by a tenuous cloud of freely-moving polymer chains which is, in effect, in solution in a continuous phase This layer prevents the particles from coming into direct contact and also ensures that, at the distance of closest approach of the two particles, the attraction between them is so small that thermal energy renders contact reversible 20 The most successful type of dispersant devised for use in dispersion polymerization according to Barrett, has been based on a block or graft copolymer which consists of two essential polymeric components-one soluble and one insoluble in the continuous phase The dispersant may be either preformed or formed in situ.

When formed in situ, a "precursor" is used, i e, a soluble polymeric component 25 that is introduced into the organic liquid serving as the polymerization medium.

The monomer system being polymerized will react with the soluble polymeric component during polymerization to form, in situ, a graft or addition copolymer dispersant When an addition copolymer dispersant is to be produced, the source of the soluble polymeric component is unsaturated and is termed a 30 "macromonomer" The main requirement for what is termed the "anchor" portion is that it be insoluble in the dispersion medium, but its effectiveness may be greatly enhanced if it has some specific affinity for the dispersed polymer The criterion of insolubility of the anchor portion also defines, in practice, the minimum size of the soluble portion For a polymer to be sufficiently insoluble in the dispersion 35 medium, the molecular weight usually has to be of the order of 1000 or greater The soluble chain attached to such an anchor portion must be at least of similar molecular weight, otherwise a stable micellar solution of dispersant cannot be formed in the dispersion medium; and precipitation occurs The minimum molecular weight of the soluble component must therefore be at least 500 to 1000, 40 which is considerably greater than the minimum requirement for an effective steric barrier.

Based upon this technology, a large number of patents have been issued The Barrett text lists some 200 issued United States and foreign patents Yet, despite this considerable body of technology, applicants are unaware of any attempts prior to 45 the present invention to prepare polymer/polyols by employing preformed stabilizers Indeed, the prior efforts in dispersion polymerization have been directed to the use of organic liquids as dispersion mediums which have extremely low viscosities, e g -typically no more than a few centipoises at 250 C The theoretical considerations discussed in Napper, Journal of Colloid and Interface 50 Science, 32 pages 106-114 ( 1970), may well account for the fact that preformed stabilizers have not been used heretofore to stabilize polymers/polyols, despite the recognition that the stability of polymer/polyols requires the presence of a graft or addition copolymer which is fortuitously formed in situ in conventional polymer/polyol from the polymer and polyol Thus, the Napper article leads to the 55 conclusion that stabilization would not be effective if the solvatable portion has a chemical composition identical to the polymerization medium.

In general, the present invention is predicated on the discovery that improved polymer/polyols can be prepared by utilizing certain preformed dispersants or stabilizers These polymer/polyols, in contrast to polymer/polyols made by prior 60 techniques, are characterized by stability satisfactory to allow commercial production and use of one or more of the following characteristics: (I) higher amounts of styrene or other comonomer when acrylonitrile copolymer polymer/polyols are being prepared, ( 2) higher polymer contents or ( 3) the use of lower molecular weight polyols The particular dispersant employed and the 65 1,598,930 concentration utilized vary with respect to the monomer system used in preparing the polymer/polyols.

More particularly, the preformed dispersant or stabilizer used comprises a polymeric anchor portion tailored to the monomer system being utilized and a solvatable portion compatible with the polyol In contrast to the prior efforts in 5 dispersion polymerization in which the primary focus is directed to designing stabilizers based upon the relative solubility and insolubility of the solvatable and anchor portions in the reaction medium, the present invention is based in part on the discovery that enhanced stability of polymer/polyols requires that the polymeric anchor be varied in relation to changes in the monomer system being 10 utilized in producing the dispersed phase (i e the polymer).

The stabilizers of the present invention are characterized by extremely high viscosities in comparison to viscosities of useful polymer/polyols Thus, the stabilizers typically possess viscosities well in excess of 40,000 centipoises at 25 C as compared to polymer/polyols which have viscosities below 40,000 centipoises 15 The present invention is thus directed to a process for producing a copolymeric graft or addition stabilizer having a viscosity in excess of 40,000 centipoises at 25 C, which process comprises polymerising, in an inert solvent using a free radical catalyst, an anchor portion (a) consisting of a copolymer of two ethylenically unsaturated monomers, wherein one of the said monomers is capable 20 of forming a polymer which is insoluble in the monomer from which it is formed, and wherein the other of the said monomers is capable of forming a polymer which is soluble in the monomer from which it is formed, in the presence of a solvatable portion (b) consisting of a propylene oxide polymer having a number average molecular weight of at least 800, wherein the solvatable portion (b) is: 25 ( 1) a polyoxypropylene polyol consisting essentially of the reaction product of a saturated polyhydric starter and propylene oxide or propylene oxide and ethylene oxide, ( 2) the reaction product of a propylene oxide polymer and an organic compound capable of reaction with the propylene oxide polymer to provide a 30 reaction product with terminal, ethylenic unsaturation, with the proviso that the said reaction product has, on the average, terminal, ethylenic unsaturated on only one end, or ( 3) the reaction product of a propylene oxide polymer and tolylene dissocyanate 35 In accordance with the invention there is also provided a copolymeric stabilizer having a viscosity in excess of 40,000 centipoises at 25 C, comprising:

(a) an anchor portion consisting of a copolymer of two ethylenically unsaturated monomers, wherein one of the said monomers is capable of forming a polymer which is insoluble in the monomer from which it is formed, and wherein 40 the other of the said monomers is capable of forming a polymer which is soluble in the monomer from which it is formed, chemically bonded to (b) a solvatable portion having a number average molecular weight of at least 800 consisting of the reaction product of a propylene oxide polymer and tolylene diisocyanate 45 Our copending Application No 52827/77 (Serial No 1598929) describes and claims processes for preparing the desired polymer/polyols, as well as polyurethanes prepared therefrom, and these details will not be repeated here.

The preparation of these polymer/polyols is carried out in the presence of a preformed stabilizer tailored to the monomer system being employed The 50 stabilizer, in a functional sense, is present in an amount sufficient to ensure that satisfactory stabilization will result, viz -the' desired filtation hindrance, centrifugible solids level and viscosity are provided.

According to one aspect of the present invention, the solvatable constituent of the stabilizer is formed from a polypropylene oxide macromonomer having 55 terminal monoethylenic unsaturation The minimum number average molecular weight of the macromonomer should be at least 800, preferably at least 1800 and, most preferably at least 2600 Macromonomers with molecular weights up to 5000 or even more can be utilized if desired.

The macromonomer can be suitably prepared by condensing a polypropylene 60 oxide material having hydroxyl functionality with any organic compound capable of providing the desired monoethylenic unsaturation Monols, diols and triols are preferred; however, conceptually, tetrols and higher functionality polyols could also be employed As is known, polypropylene oxide materials of this type can be prepared by forming adducts of propylene oxide with lower molecular weight 65 1,598,930 monols, diols, and triols such as, for example, glycerine, dipropylene glycol, and butanol The macromonomer may contain minor amounts of other materials Thus, poly(oxypropylene-oxyethylene) materials containing up to 10 to 20 weight percent oxyethylene or so may be suitably used The condensation reaction to form the macromonomer is known and can be carried out, for example, in an inert solvent 5 such as benzene at elevated temperatures in the range of 800 C to 1150 C.

Insofar as the constituent providing the monoethylenic terminal unsaturation is concerned, any compound which will condense with the polypropylene oxide material may conceptually be employed However, in practice, the compound selected should possess unsaturation of a type reactive in vinyl polymerization For 10 this reason, compounds containing allylic unsaturation show no advantage; in fact, the resulting stabilizers have been found to be ineffective As representative examples, the desired unsaturation may be imparted by utilizing either acrylic acid or methacrylic acid Use of these two compounds has not demonstrated any differences in utility of any particular significance Process-wise, the unsaturation 15 can be provided by using conventional transesterification or ester interchange techniques In addition, the unsaturation could be imparted by employing, e g.

maleic anhydride A further useful embodiment can be provided by reacting toluene diisocyanate with the propylene oxide polymer to form an intermediate product which is thereafter reacted with hydroxyethylacrylate to form the 20 macromonomer The use of these latter examples provides a process advantage in that the filtration step needed when an acrylate is formed is obviated.

When diols or higher functionality polyols are employed, it is important that the reaction forming the macromonomer be carried out in a fashion designed to react to remove, on the average, only one of the hydroxyl groups of the polyol The 25 utilization of stabilizers formed from macromonomers having on the average significantly more than one end of the chain capped with monoethylenic unsaturation have proved to be relatively ineffective in stabilizing polymer/polyols.

The dispersants or stabilizers may then be prepared by grafting the monomers used as the anchor portion to the macromonomer As used herein, the term 30 grafting" includes the species formed by free radical addition polymerization as well as the species formed via hydrogen abstraction The reaction may be carried out in any inert solvent Representative examples include toluene, benzene, ethylbenzene and a mixture of toluene and methylethylketone The solids concentration (i e -total weight of the macromonomer and monomers for the 35 anchor portion) can vary within wide limits; and it is suitable to carry out the formation of the stabilizer with a solids concentration of from 10 to 60 percent, based upon the total weight of the solids and solvent, preferably from 10 to 40 percent, and most preferably 30 to 40 percent.

The weight ratio of the macromonomer to the monomers used to form the 40 anchor portion can also be varied within a wide range However, the ratio selected will generally influence the compositional character of the dispersant formed due to the effects on the type of grafting reaction which predominates It will accordingly be generally preferred to utilize at least about 50 percent of the macroinonomer, and it is particularly preferred to use a solids concentration in 45 which the macromonomer constitutes from 60 to 70 percent of the total with relatively high molecular weight macromonomers and about 80 percent or so with lower molecular weight macromonomers.

It is preferred to select the parameters so that a homogeneous stabilizer results as opposed to one which coacervates (viz -separates into layers) The advantage of 50 having a homogeneous product to handle instead of one which has layers and must be mixed before each use is apparent Whether the product coacervates or not is believed to be dependent upon the extent of grafting For a given catalyst the amount of the macromonomer used in relation to that of the vinyl monomers will influence this result 55 The catalyst used, and the concentration, can suitably be the same as those discussed in Application No 52827/77 (Serial No 1598929) in connection with the formation of polymer/polyols The selection of the catalyst will also, to some extent, influence the type of grafting reaction which will predominate For example, the use of a peroxide catalyst has been found to accentuate grafting via 60 hydrogen abstraction.

In any instance, grafting via both hydrogen abstraction and vinyl polymerization will taken place; and the resulting stabilizer will accordingly be a mixture of various compounds The exact product mixture is not of particular 1,598,930 significance Indeed, the mixture will typically also include unreacted macromonomer and vinyl monomers in addition to the various grafted species.

With respect to use of the stabilizers in connection with forming polymer/polyols, the resulting crude reaction stabilizer mixture may be either added directly to the polyol or separation of the solvent and/or unreacted materials 5 may be effected For example, the unreacted macromonomer in the crude product may be extracted by utilizing a solvent such as hexane Addition of the stabilizer in the solvent in which it is formed is a highly advantageous processing technique, allowing easier dissolution into the polyol The solvent may then be stripped out, if desired, by conventional techniques 10 To provide effective stabilization, it has been found that the stabilizer should be compatible with the polyol being employed so that a homogeneous mixture is provided The resulting mixture, visually, may be either a clear solution or opaque depending upon the particular composition of the stabilizer However, if solids are visually detectable in the resulting system, the use of a stabilizer will typically 15 provide,'-at best, little stabilizing effect.

The crude stabilizer may-be employed, without any refinement or processing other than, if desired, the stripping out of the solvent in which the stabilizer was prepared The amount of the crude stabilizer which may be employed should be sufficient to achieve the desired stability It has been found that a small amount 20 (e.g -about 0 2 %, based upon the weight of the polymer/polyol) provides a dramatic effect on at least some of the physical properties of the polymer/polyol in comparison to the preparation of the same polymer/polyol without the stabilizer.

Typically, this effect is evident from a reduction in the viscosity as well as increased stability as indicated by a reduction of the quantity of centrifugible solids Indeed, 25 insofar as these properties are concerned, the addition of 0 4 weight percent of stabilizer in certain cases provides properties equivalent to those obtained by employing 1 4 weight percent.

It is, however, preferred to use an amount of stabilizer which is sufficient to provide the desired greater stability as indicated by filtration hindrance 30 characteristics; and achieving superior filtration hindrance will generally require the addition of an amount of stabilizer in excess of that required to achieve satisfactory viscosity and centrifugible solids characteristics Accordingly, it will generally be desirable to add from 1 to 5 percent or even more stabilizer, based upon the weight of the polymer/polyol Larger amounts could, of course, be 35 employed but there will generally be no functional incentive to use excessive amounts.

The acrylonitrile copolymer polymer/polyols obtained using the stabilizers of the present invention have particles which are spherical in shape This is achieved by use of the stabilizers of the present invention as well as employing a monomer 40 system in which the styrene or other comonomer is present in amounts in excess of about 40 percent by weight.

In marked contrast to prior efforts in stabilizing polymer dispersions in various organic liquids wherein the primary emphasis was placed on the relative insolubility of the anchor portion in the liquid, as has been alluded to previously, it 45 has been discovered that a further factor must be considered More specifically, it has been found that the anchor portion of the stabilizers of the present invention must be coordinated with the type of monomer or monomers used to form the polymer portion of the polymer/polyol Conceptually, it is theorized that effective stabilization requires a careful balance between the solvatable portion and the 50 anchor portion of the stabilizer If the solvatable portion dominates, it is believed that the anchor portion will be, in effect, pulled into solution thereby losing the contact with the polymer particles which is essential for optimum stability On the other hand, if the anchor portion dominates, it is believed that the solvatable portion will not provide the required barrier for stabilization In this application, 55 the terminology "balanced stabilizer" refers to a stabilizer having the careful balance between the solvatable and anchor portions which has been discussed herein.

Considering this aspect more fully some of the vinyl monomers useful in forming polymer/polyols are not solvents for their polymers (e g acrylonitrile) 60 whereas other useful monomers (e g -styrene) are solvents for their polymers The present invention is predicated, in part, on the discovery that effective stabilization requires an anchor portion tailored in composition to the solvency, or lack thereof, of the monomer or monomers used for forming the dispersed polymer portion of the polymer/polyol 65 1,598,930 Thus, in accordance with the present invention, the anchor portion is formed from at least two monomers, one of which is not a solvent for its polymer and one which is Further, the respective monomer weight ratio used are preferablymaintained within the range of from 30/70 to 80/20 (weight ratio of monomer which is not a solvent to the amount of monomer which is) The range of useful monomer 5 ratios to form the anchor within this range will then be at least principally dependent upon the solvency characteristics of the monomer or monomers being used to form the polymer portion.

In the ensuing discussion for sake of simplicity, the monomer ranges for the anchor portion will be set forth in terms of acrylonitrile to styrene ratios useful in 10 forming polymer/polyols from a monomer system of acrylonitrile and/or styrene It should, however, be appreciated that the same principles are also applicable to other monomer systems and to anchor portions formed from other monomers.

This particular aspect of the present invention will now be described with reference to the accompanying drawings, in which: 15 Figure 1 is a tie-line diagram showing the anchor portion compositions of the preformed stabilizer of the present invention useful in forming polymer/polyols (line AB) when the polymer portion is formed by polymerizing from 30/70 to 60/40 acrylonitrile/styrene (line CD); Figure 2 is a tie-line diagram and illustrates the preferred anchor portion 20 compositions (line EF) for forming the polymer/polyols described in connection with Figure 1 (indicated by line GH); Figure 3 is a tie line diagram and shows the anchor portion compositions of the preformed stabilizer of this invention useful in forming polymer/polyols (line IJ) when the polymer portion is formed by polymerizing from 0/100 to 30/70 25 acrylonitrile/styrene (line KL); Figure 4 is a tie-line diagram illustrating the preferred anchor portion compositions (line MN) for forming the polymer/polyols described in connection with Figure 3 (line OP), and, Figure 5 is a tie-line diagram showing the anchor portion compositions of the 30 stabilizers of this invention useful in forming polymer/polyols (line QR) when the polymer portion is formed by polymerizing from 60/40 to 100/0 acrylonitrile/styrene (line ST).

When the polymer portion of the polymer/polyol is formed by polymerizing, by weight, a monomer system of from 30/70 to 60/40 acrylonitrile/styrene, optimum 35 stabilization requires that the anchor portion have a composition within line AB of Figure 1, preferably within the line EF of Figure 2 An anchor portion of 30/70 acrylonitrile/styrene is particularly preferred, especially for 40/60 and 50/50 acrylonitrile/styrene monomer systems.

As the amount of styrene in the monomer system is increased above 70 percent 40 (i.e -0/100 to 30/70), the anchor portion should have a composition within the line IJ of Figure 3, a composition within line MN of Figure 4 being preferred For use with 20/80 and 30/70 acrylonitrile/styrene monomer systems, an anchor portioncomposition formed from 50/50 acrylonitrile/styrene is preferred On the other hand, with increasing amounts of acrylonitrile (i e -60/40 to 100/0, more 45 particularly, 60/40 to 80/20), useful anchor portions can be formed from a composition defined by line QR of Fig 5.

It should be appreciated that the exemplary monomer weight ratios set forth do not present absolute limits Rather, these ratios provide a representative range in which effective stabilization can be achieved Some experimentation within the 50 general concept may be needed to provide an optimum stabilization effect for a particular monomer system Indeed, as can be seen from the ranges previously set forth for the anchor portions, there is some overlap Thus, as one example the lower limit of the high styrene range (i e -30/70) polymer/polyols coincides with the upper limit of the intermediate range polymer/polyols This coincidence causes 55 an overlap in the sense that the useful anchor portion ratios for a 30/70 acrylonitrile/styrene polymer/polyol determined from the intermediate range is from 30/70 to 80/20 (line AB of Figure 1) while the determination from the high styrene range polymer/polyols would indicate useful anchor portions of 30/70 to 50/50 (line IJ of Figure 3) There is a similar coincidence at the upper limit of the 60 intermediate range polymer/polyols as can be seen by comparing Figures 3 and 5.

The indicated useful anchor portion ranges at these points of coincidence should not be interpreted individually; rather, these ranges should be considered together Accordingly, the overall interpretation is that, in the intermediate range where significant relative amounts of both acrylonitrile and styrene are present, the 65 1,598,930 widest latitude for the ratio of the monomers used for the anchor can be employed.

However, as either the styrene or acrylonitrile in the monomer system used increases to a disproportionate level, the ratio of useful monomers for the anchor correspondingly becomes narrower.

For this reason, as the amount of styrene in the monomer system being used 5 approaches 70 %, the range of the more useful anchor portion compositions will correspond to 30/70 to 50/50 Employing anchor portions with compositions in the range of 50/50 to 80/20 will decrease the effectiveness of the resulting stabilizers somewhat Similarly, as the amount of acrylonitrile in the monomer system approaches 60 %, the range of the more useful anchor portions will correspond to 10 50/50 to 80/20 Stabilization using anchor portions having 30/70 to 50/50 compositions will generally be less effective than anchors having acrylonitrile contents in excess of 50 %.

The principal thrust of this invention is thus that the anchor portion should be formed from at least two monomers, one of which is a solvent for its polymer and 15 one of which is not; and, further, the relative monomer weight ratio utilized in forming the anchor portion must be tailored to the monomer system being used in forming the polymer/polyol This also serves to illustrate the greater flexibility of this embodiment as compared to the precursor technique As is apparent, utilizing a precursor necessitates that the anchor portion will be identical in composition to 20 the polymer portion of the polymer/polyol being prepared Precursors are thus only potentially useful in the range where the effective anchor fortuitously happens to match the useful composition required for the particular monomer system being employed Moreover, while the reasons are not fully understood, a preformed stabilizer has been found to provide significantly improved stabilization in relation 25 to stabilization achieved by a precursor technique.

In accordance with yet another aspect of the present invention, effective stabilizers can be prepared without the initial step of forming a macromonomer To this end, effective stabilizers can be prepared by polymerizing in an inert solvent with a free radical catalyst a polypropylene oxide material (forming the solvatable 30 portion) with the monomers forming the anchor portion.

In this embodiment, the same considerations, in general, which are involved in forming stabilizers using the macromonomer technique are equally applicable.

Thus, the propylene oxide material may be the adduct of propylene oxide with e g, a monol, diol, or triol The minimum molecular weight of the resulting adduct 35 should be at least 800, preferably at least 1800 and most preferably 2600 However, for reasons which will be apparent in the ensuing discussion, it is preferred to employ materials having relatively high molecular weights.

More specifically, in this embodiment, the stabilizer consists of graft species obtained only by hydrogen abstraction Accordingly, it is preferred to employ a 40 free radical catalyst which enhances hydrogen abstraction, such as a peroxide catalyst Further, relatively large solvatable portion molecular weights are required to ensure that the desired steric barrier is provided.

Inasmuch as this technique eliminates the need to form the macromonomer, stabilizers produced by this technique offer real economic advantages While it has 45 been found that useful concentrations may require up to twice the amount of stabilizers made with the macromonomer technique to provide equivalent stability characteristics, there is still a significant economic advantage in using this alternative technique.

In connection with this technique, a further aspect of this invention provides 50 modifying the polypropylene oxide material by incorporation of a group which enhances hydrogen abstraction While various compounds are known and may be used, a particularly useful solvatable portion comprises the reaction product of the propylene oxide material with toluene diisocyanate This requires that the propylene oxide material either contain, as formed, at least one functional group 55 reactive with the diisocyanate or be modified after preparation to introduce the requisite functional group or groups Regardless of the type, it is preferred in this embodiment that the propylene oxide material be monofunctional, although difunctional materials are satisfactory The use of tri or higher functionality materials should be avoided as extensive cross-linking has been found to occur 60 Hydroxyl groups are particularly preferred as the functional group The diisocyanate is desirably used in an amount sufficient to ensure reaction of the isocyanato groups.

Moreover, the utilization of this technique to prepare polymer/polyols results in an unexpected advantage in forming polyurethane foams Thus, in contrast to 65 1,598,930 polyurethane foams made using polymer/polyols employing stabilizers prepared by the macromonomer technique, polyurethane foams made using polymer/polyols prepared by this alternative technique, for some reason, exhibit less tendency to collapse This allows the use of the same foam formulation as would be used with a polymer/polyol formed by known techniques The advantages are apparent 5 In accordance with yet another aspect of the present invention, no separate equipment is needed to prepare the stabilizers Thus, in a commercial run to prepare polymer/polyols, the equipment to be used may be initially employed to react the solvatable and anchor portions to form the required amount of stabilizer.

After completion, the polymer/polyol run can be carried out in the same 10 equipment The economic advantages involved can be significant, particularly in the mode where the solvatable portion used is an unmodified polypropylene oxide material In such a situation, it is possible to use the polyol as the solvatable portion and the same monomers to be employed to form the polymer part of the polymer/polyol as the anchor portion, thereby requiring only the solvent used to 15 form the stabilizer as a further raw material.

Regardless of the mode of preparation used for the solvatable portion, the resulting stabilizers of this invention are characterized by relatively high viscosities in relation to polymer/polyols having comparable polymer contents Thus, after removal of the solvent used to prepare the stabilizer, the stabilizer will be a solid or 20 a liquid whose viscosity will typically range from 60,000 up to 260,000 or more centipoise at 250 C.

The physical character of the stabilizers, after solvent removal, ranges from a paste to a solid, depending upon the type of solvatable portion utilized and the weight ratio of the monomers used to form the anchor portion In the 25 macromonomer mode, the stabilizers are usually solid or semi-solid regardless of the monomers used for the anchor With the free radical grafting mode using a polypropylene oxide material, the character of the stabilizer varies from a solid or semisolid with an anchor portion made from a 30/70 acrylonitrile/styrene monomer charge to a paste when the acrylonitrile/styrene-weight ratio is increased to 50/50 or 30 higher While the chemical compositions of the preformed stabilizers of this invention may be essentially identical with the graft or addition copolymers formed in situ in conventional polymer/polyol preparation, there are three basic differences In the first instance, the process parameters used to prepare the preformed stabilizers can be coordinated to enhance grafting efficiency, a 35 circumstance that may not be the situation in polymer/polyol production where the in situ formation of the graft or addition copolymer is incidental Secondly, a preformed stabilizer can be tailored to the particular monomer system being used and thus does not suffer from the serious limitation of being identical in composition to the monomer system and polyol being used in the polymer/polyol 40 preparation Lastly, the in situ formed graft or addition copolymer does not have practical utility apart from the particular polymer/polyol in which it is formed because it is difficult to isolate.

As used in the Examples appearing below, the following designations, symbols, terms and abbreviations have the indicated meanings: 45 "Theoretical molecular weight" of a polyol denotes a molecular weight calculated using the equation previously set forth based on the functionality of the starter used to produce the polyol and the experimentally determined hydroxyl number of the polyol.

"Molecular weights" of polyols are number average molecular weights 50 "rpm" denotes revolutions per minute.

"mg" denotes milligrams.

"A" denotes acrylic acid.

"MMA" denotes methylmethacrylate.

"MA" denotes methacrylic acid 55 "TBPO" denotes t-butyl per-2-ethylhexoate.

"AZO" denotes 2,2 '-azobisisobutyronitrile.

"pcf" denotes pounds per cubic feet.

"Sol" denotes solution.

"S" denotes solid 60 " denotes percent by weight.

"wt" denotes weight.

"Ratio" denotes weight ratio.

1,598,930 "Polypropylene oxide material I"-a monohydroxyl polypropylene oxide produced from propylene oxide and butanol having a number average molecular weight of about 800.

"Polypropylene oxide material II"-a monohydroxyl propylene oxide produced from a propylene oxide and butanol having a number average molecular 5 weight of about 1800.

"Polypropylene oxide material III"-a monohydroxyl polypropylene oxide produced from propylene oxide and butanol having a number average molecular weight of about 2600.

"Polypropylene oxide material IV"-a polypropylene oxide diol produced 10 from propylene oxide and dipropylene glycol and having a theoretical number average molecular weight of about 4000.

"Polypropylene oxide material V"-a propylene oxide triol produced from propylene oxide and glycerine and having a theoretical number average molecular weight of about 6000 15 "Polyol I"-a polypropylene oxide triol produced from propylene oxide and glycerine and having a theoretical number average molecular weight of about 3000.

Preparation of Macromonomers The polypropylene oxide material, methacrylic acid or other material used to provide the terminal unsaturation, solvent and other constituents (e g acidic 20 catalyst and the like) were placed in a 4-necked amber glass 5-liter flask equipped with a thermometer, magnetic stirrer, boiling stones and a 10-tray Oldershow column with decanting still head The mixture was refluxed for from about 8 to 12 hours at a temperature in the range of from about 80 to about 110 C, and the water from the reaction was collected The product was then neutralized at 50 C 25 with sodium hydroxide in water (to form a salt) The mixture was stirred for about one hour and allowed to set for 16 hours The water was then azeotroped from the product The dry product was mixed with a commercially available filter aid and filtered under 100 pounds of pressure at 100 C to remove the salt (e g sodium ptoluene sulfonate or sodium sulfate) 30 Preparation of Dispersant or Stabilizer Unless otherwise indicated, the procedure employed was as follows The monomers, macromonomer or polypropylene oxide material, catalyst and solvent were placed in a 500 milliliter 4-necked flask equipped with a stirrer, dropping funnel, water-cooled condenser, temperature control and nitrogen inlet and outlet 35 The flask was heated while stirring under a slight nitrogen purge Additional monomer or monomers and the remainder of the catalyst charge were added over a period of about one hour The ratio of monomer or monomers used to the macromonomer or polypropylene oxide material was in the range of, by weight, 30-50 monomer or monomers/50-70 macromonomer or polypropylene oxide 40 material; and the total weight of these components in the solvent was in the range of 30 to 50 percent The mixture was heated and stirred for an additional hour, cooled and stored in a glass jar.

EXAMPLES 1-7

These Examples illustrate the preparation of macromonomers using 45 polypropylene oxide materials having molecular weights varying from about 800 to about 5000, with the terminal monoethylenic unsaturation being provided by using either methacrylic acid or acrylic acid.

The process used was the same as has been previously set forth, and the s O parameters are set forth in Table I: 50 1,598,930 1 1,598,930 11 TABLE I

Example No I 2 3 4 5 6 7 Polypropylene oxide, material, type gms.

Unsaturated acid, type gms.

Solvent, type gins.

Monomethyl ether hydroquinone, gms (I) 2,6-dimethyl 2,4,6octatriene, gms ( 1) p-toluene sulfonic acid, gins ( 2) sulfuric acid gms ( 2) I 3000 MA 385 Benzene 735 0.15 II III A 127 Toluene MA Benzene 1.0 0 6 A Benzene A Toluene IV V A 54 Benzene 0.6 0 6 1 ( 1) Inhibitor ( 2) Catalyst EXAMPLES 8-28

These Examples show the preparation of stabilizers having an acrylonitrilestyrene copolymer anchor portion and, except for Example 19, a solvatable portion formed with a terminal, monoethylenically unsaturated macromonomer, the polypropylene oxide material used in preparing the macromonomer having a molecular weight in Examples 8-23 of about 2600 and in Examples 24-28 of about 800.

The stabilizers were prepared by terpolymerizing acrylonitrile, styrene and the macromonomer at a temperature of 100 C, with the exception of Examples 810 which were polymerized at 90 C and Example 11 wherein the polymerization was carried out at 80 C The procedure for Example 19 was carried out at 100 C and was similar to that described except that the solvatable portion was an unmodified polypropylene oxide material, the resulting graft specie being formed via hydrogen abstraction The solvents used in preparing the stabilizers were varied as were the relative amounts of the solvatable and anchor portions The resulting stabilizers were evaluated in terms of their homogeneity, solubility in Polyol I and stabilizing effectiveness as observed in a general screening test conducted by preparing a polymer/polyol in the presence of the stabilizer The macromonomer and stabilizer compositions as well as the properties of the stabilizers are set forth in Table II:

Example No.

A 46 Benzene Example No.

Macromonomer Polypropylene oxide material Unsaturated acid TABLE II

11 12 13 14 15 16 17 III MA Stabilizer Solvent ( 1) Ratio acrylonitrile to styrene monomer % Solids ( 2) % Vinyl content Reactants ( 3) Stabilizer (NMR) ( 4) Catalyst Stabilizer Properties After standing ( 5) Solubility in Polyol I Stabilizing ability ( 7) Tol Tol Tol Ben Tol Tol E Ben Tol Tol Tol/MEK 30/70 30/70 30/70 30/70 30/70 30/70 30/70 15/18 85/15 30/70 27.5 27 7 25 7 31 7 45 5 47 1 27 4 25 2 31 9 26 1 41.6 TBPO SS Good Good 38.1 AZO C Poor Poor 54 TBPO C Poor Poor 34.8 NS Good Good 44.5 NS V Poor Poor 26.2 SS V Good V Good 38.7 SS Good Poor 33.7 NS Good Poor 50 33 38 3 NS( 6) Good Poor SS Good Poor Example No.

Macromonomer Polypropylene oxide material Unsaturated acid TABLE II (cont).

18 19 20 21 22 III MA None MA MA A 23 24 25 26 27 28 A I MA Stabilizer Solvent ( 1) Ratio acrylonitrile to styrene monomer % Solids ( 2) %Vinyl content Reactants ( 3) Stabilizer (NMR) ( 4) Catalyst Stabilizer Properties After standing ( 5) Solubility in Polyol I Stabilizing ability ( 7) Polyol I Tol 30/70 30/70 75/25 30/70 30/70 30/70 30/70 30/70 30/70 30/70 30/70 28 5 32 7 28 6 29 1 29 9 28 7 30 9 28 8 31 3 36 1 TBPO NS Good Poor 40.9 C Good Poor 34.2 NS( 2) Good Poor 32.6 NS Good Good 45.4 NS Good Poor 50 30 34.5 52 32 7 NS Good Good NS Poor Poor NS Good Poor 20 30 67.4 26 4 33 4 NS Poor Poor NS Good Fair NS Good Fair hi t Ao cc TABLE II

Footnotes (I) Tol: Toluene, Ben: benzene, E Ben: ethyl benzene, Tol/MEK: 50/50 mixture of toluene and methyl ethyl ketone.

( 2) Solids refers to the residue that remains when solvent is evaporated from 5 stabilizer solution.

( 3) Percent by weight of vinyl monomers based on total weight of vinyl monomers and macromonomer reactants ( 4) Percent by weight of vinyl polymer in residue that remains when solvent is evaporated from stabilizer solution 10 ( 5) SS-a slight settling of a small amount of polymer out of the solution.

C -stabilizer separated into a upper and tower layer (coacervated).

NS-stabilizer showed no tendency to settle out of solution.

( 6) Stabilizers did not settle but were opaque with a light orange color.

( 7) This was evaluated in these and subsequent Examples by observation of 15 the resulting viscosity and centrifugible solids when used to form polymer/polyols in Polyol I with an acrylonitrile/styrene ratio of 40/60.

As can be seen, superior stabilization is provided with a stabilizer formed with a polypropylene oxide material of 2600 molecular weight, TBPO as the catalyst and toluene or benzene as the solvent As shown in Examples 8, 13 and 23, a 20 concentration of 30-50 % vinyl monomer is desirable.

EXAMPLES 29-35 These Examples demonstrate the preparation of additional useful stabilizers with polypropylene oxide materials having molcular weights ranging from about 800 to about 5000 and with anchor portions wherein the acrylonitrile/styrene ratio 25 varies from 25/75 to 50/50.

The terpolymerization was carried out using TBPO catalyst; and the results are set forth in Table III, the stabilizers being evaluated in terms of solubility in Polyol I and stabilizing effectiveness observed in a general screening conducted by forming a polymer/polyol in the presence of the stabilizer: 30 1,598,930 Example No.

Macromonomer Polypropylene oxide Unsaturated acid Stabilizer Solvent Ratio acrylonitrile to styrene monomer % Solids ( 1) Vinyl content of Reactants ( 2) Catalyst Polymerization Temperature Stabilizer Properties Solubility in Polyol I Stabilizing Ability ( 3) Toluene Toluene Toluene Toluene Toluene 27/75 20.6 TBPO Good Good 30/70 TBPO Good Good 30/70 30.8 TBPO Good Poor 50/50 TBPO Good Good 45/55 31.3 TBPO 104 Good Good Xylene 45/55 47.6 TBPO Good Good (I) Solids refers to the residue that remains when solvent is evaporated from stabilizer solution.

( 2) Percent by weight of vinyl monomers based on total weight of vinyl monomers and macromonomer reactants.

( 3) Examples 29-31 evaluated with a polymer/polyol formed from an acrylonitrile/styrene monomer weight ratio of 40/60 while Examples 32-35 were evaluated using a somewhat higher styrene content in the monomer ratio (e g -about 30/70).

IV A TABLE III

V A II A III A A A None Xylenm 50/50 46.0 34 TBPO Good Good so ? O \ O ui 1,598,930 15 As can be seen from Examples 34 and 35, stabilizers with good stabilizing ability were also provided when the polypropylene oxide material was not condensed with acrylic acid or the like to provide a macromonomer with terminal, monoethylenic unsaturation.

EXAMPLES 36-38 5 These Examples show the preparation of stabilizers of the present invention in equipment designed for continuous polymerization using the thus-prepared stabilizers to form polymer/polyols in the same equipment The equipment comprised a tank reactor fitted with baffles and an impeller The feed components were pumped to the bottom of the reactor continuously after going through an 10 inline mixer to ensure complete mixing of the feed components before entering the reactor The internal temperature of the reactor was controlled to within 10 Centigrade by controlled heating or cooling to the outside of the reactor The product from the top of the reactor flowed out of the top of the reactor to a back pressure regulator adjusted to 10 pounds per square inch gauge back pressure and 15 then through a water cooled tubular heat exchanger to a product receiver Portions of the crude product were vacuum stripped at 2 millimeters pressure and 120 to 130 degrees C for testing.

The experimental conditions and results are set forth in Table IV, the solvent, solvatable portion and catalyst being added as one stream and the 20 monomers used being added as the other stream.

Example No.

Preparation Solvatable Portion of Stabilizer Amount of Solvatable Portion, wt % in total feed Amount of Solvent (Toluene), wt % in total feed Catalyst Type Catalyst Conc, wt % in total feed Ratio of Acrylonitrile to Styrene for anchor portion, wt % Total Monomer Content, wt % in total feed Ratio of Vinyl Monomers to Solvatable Portion in Feed Reaction temperature, C.

Toluene+Solvatable Portion+ Catalyst Feed Rate, gm/hr Monomer Feed Rate, gm/hr Residual Acrylonitrile, % Styrene, % Conversion Acrylonitrile, % Styrene / Combinea, /o Total Poly A in Unstripped Product by Calc, wt % Total Poly S in Unstripped Product by Calc, wt % Total Polymer in Unstripped Product by Calc, wt % Ratio of Vinyl Polymer to Soluble Portion by Calc wt % Properties Solids (Nonvolatiles), wt % (by analysis) Calculated Solids (nonvolatiles), wt % Remarks TABLE IV

36 37 Polypropylene oxide material V 23.49 46.99 TBPO 1.4 50/50 28.11 54.48/45 52 135-140 1087 425 5.34 2.45 61.40 82.29 77.21 9.37 12.56 21.93 46.22/53 78 44.66 44.39 Stable ( 1) 21.903 ( 2) 65.754 TBPO 1.8 30/70 10.51 Polypropylene oxide material V 24.18 48.35 Di-t-butyl peroxide 1.45 30/70 26.02 32.43/67 57 51 83/48 17 140 1635 192 1.53 3.76 52.41 49.87 50.63 1055 371 t/I \ O O D O Toi 1.74 3.87 5.61 20.41/79 6 29.33 27.22 Stable

40.09 Stable ( 1) Reaction product of 2 moles of a polypropylene oxide-butanol adduct of about 2550 molecular weight and 1 mole of TDI in toluene.

( 2) On solvent-free basis.

17 1,598,930 17 The thus-formed stabilizers were then used to form acrylonitrile/styrene polymer/polyols in the same equipment as described in copending Application No.

52827/77, (Serial No 1598929).

EXAMPLES 39-47 These Examples illustrate the physical appearance of the stabilizers of the 5 present invention and their viscosity characteristics.

Table V sets forth the experimental conditions and results for a series of stabilizers made in toluene from various solvatable and anchor portions:

Example No.

Preparation ( 1) Solvatable Portion Anchor portion, A/S Ratio Anchor portion/Solvatable portion Solid Content, % ( 2) 70/30 40/60 33,5 ( 3) 50/50 51/49 43.2 TABLE V

41 42 ( 4) ( 2) 50/50 30/70 ( 4) 30/70 54.5/44 5 32 4/67 6 50/50 44.66 29 33 51 5 Properties Appearance of Product (solvent free) Brookfield Viscosity paste paste paste semisolid 160,200 cps 66,500 cps semisolid semisolid solid ( 1) The stabilizers of Examples 39 and 43 were prepared by the general technique previously described while the other stabilizers were made using the technique described in connection with Examples 36-38.

( 2) Described in Example 37.

( 3) Polypropylene oxide triol capped with about 14 % ethylene oxide, having a number average molecular weight of about 6000 and a hydroxyl number of about 26.

( 4) Polypropylene oxide material V.

o 00 ( 4) 30/70 30/70 30.5 ( 4) 30/70 52/48 ( 4) 30/70 43/57 \.0 2 o c O solid As shown, the physical appearance of the stabilizers, all made by the free radical grafting mode, varied from solids or semi-solids (Examples 42-46) when using an anchor portion made with a 30/70 acrylonitrile/styrene monomer ratio to pastes when monomer ratios of increasing acrylonitrile content were employed (Examples 39 41) Also, the viscosities of these stabilizers were well in excess of the viscosities of polymer/polyols prepared from comparable monomer contents.

A further stabilizer was prepared for evaluation, using the technique described in Example 36-38 The experimental conditions and results are set forth in Table VI TABLE VI

Example No.

Solvatable Portion of Stabilizer Amount of Solvatable Portion, wt % in total feedAmount of Solvent (Toluene), wt % in total feed Catalyst Type Catalyst, wt % in total feed Ratio of Acrylonitrile to Styrene, wt % Total Monomer Content, wt % in total feed Ratio of Vinyl Monomers to Solvatable Portion in Feed Reaction Temperature, C Toluene+Solvatable Portion+Catalyst Feed Rate, gm/hr Monomer Feed Rate, gm/hr Product Rate, gm/hr Material Balance, % Residual Acrylonitrile, % Styrene, % Conversions, Acrylonitrile, % Styrene, o%' Combined, %O Total Poly A in Unstripped Product by Calc wt %o Total Poly S in Unstripped Product by Calc, wt % Total Polymer in Unstripped Product by Calc, wt % Ratio of Vinyl Polymer to Soluble Portion by Calc, wt % Calculated Hydroxyl No of Unstripped Product, mg KOH/gm Total Poly A on (Toluene-Free) Product by Calc, wt % Total Poly S in Stripped (Toluene-free) Product by Calc, wt % Total Polymer on Stripped (Toluene-free) Product by Calc, wt % Ratio of Poly A to Poly S in Product, by Calc, wt % Solids (nonvolatiles), wt % by analysis Solids (nonvolatiles), wt % by calculation Properties Appearance Viscosity 47 (I) 24.31 48.62 TBPO 1.46 50/50 25.61 51.3/48 7 1255 432 1672 99.10 4.39 3.04 66.20 76.47 71.24 9.12 10.57 19.69 42.87/57 13 7.47 19.86 23.01 42.87 46.3/53 7 43.82 45.94 Stable

Dispersion 260,000 cps.

(I) Same as used in Example 40 In evaluating the stabilizer of Example 47, it was determined by an electron micrograph that the stripped stabilizer was in fact a dispersion A portion of the stabilizer in the toluene solvent was used to prepare two polymer/polyols as described in copending Application No 52827/77, (Serial No 1598929).

The stabilizer of Example 47 was also evaluated to determine whether it behaved similar to a polymer/polyol A 20/80 blend of the stabilizer with a conventional polyol was compared to a similar blend of a commercially available polymer/polyol by preparing foams from the two blends While some properties of the resulting foams were somewhat different, the data indicated that the stabilizer behaved like a polymer/polyol in providing a foam with load reinforcement.

Claims (1)

1. WHAT WE CLAIM IS:-

   I A process for producing a copolymeric graft or addition stabilizer having a viscosity in excess of 40,000 centipoises at 25 C, which process comprises 1,598,930 1,598,930 20 polymerising, in an inert solvent using a free radical catalyst, an anchor portion (a) consisting of a copolymer of two ethylenically unsaturated monomers, wherein one of the said monomers is capable of forming a polymer which is insoluble in the monomer from which it is formed, and wherein the other of the said monomers is capable of forming a polymer which is soluble in the monomer from which it is 5 formed, in the presence of a solvatable portion (b) consisting of a propylene oxide polymer having a number average molecular weight of at least 800, wherein the solvatable portion (b) is:(I) a polyoxypropylene polyol consisting essentially of the reaction product of a saturated polyhydric starter and propylene oxide or propylene oxide and ethylene 10 oxide, ( 2) The reaction product of a propylene oxide polymer and an organic compound capable of reaction with the propylene oxide polymer to provide a reaction product with terminal, ethylenic unsaturation, with the proviso that the said reaction product has, on the average, terminal, ethylenic unsaturated on only 15 one end, or ( 3) the reaction product of a propylene oxide polymer and tolylene diisocyanate.

   2 A process as claimed in claim 1 wherein the copolymeric stabilizer has viscosity in excess of 60,000 centipoises at 25 C 20 3 A process as claimed in claim I substantially as hereinbefore described.

   4 A process as claimed in claim I substantially as hereinbefore described in any one of the specific Examples.

   A copolymeric stabilizer when produced by a process as claimed in any one of the preceding claims 25 6 A copolymeric stabilizer having a viscosity in excess of 40,000 centipoises at C, comprising:

   (a) an anchor portion consisting of a copolymer of two ethylenically unsaturated monomers, wherein one of the said monomers is capable of forming a polymer which is insoluble in the monomer from which it is formed, and wherein 30 the other of the said monomers is capable of forming a polymer which is soluble in the monomer from which it is formed, chemically bonded to (b) a solvatable portion having a number average molecular weight of at least 800 consisting of the reaction product of a propylene oxide polymer and tolylene diisocyanate 35 7 A copolymeric stabilizer as claimed in claim 6 having a viscosity in excess of 60,000 centipoises at 25 C.

   8 A copolymeric stabilizer as claimed in claim 6 substantially as hereinbefore described.

   9 A copolymeric stabilizer as claimed in claim 6 substantially as hereinbefore 40 described in any one of the specific Examples.

   BOULT, WADE & TENNANT, 27 Furnival Street, London, EC 4 A IPQ Printed for Her Majesty's Stationery Office, by the Courier Press, Leamington Spa, 1981 Published by The Patent Office, 25 Southampton Buildings, London, WC 2 A IAY, from which copies may be obtained.