GB1598929A - Polymer/polyols via nonaqueous dispersion stabilizers - Google Patents

Description

(54) NEW POLYMER/POLYOLS VIA NON-AQUEOUS DISPERSION STABILIZERS (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 and by the following statement:- The present invention relates to processes for producing polymer/polyol compositions using a preformed stabilizer, to the polymer/polyol compositions thus produced and to polyurethane formed from such polymer/polyol compositions.

.The invention further relates to the preformed stablizers per se.

Polymer/polyol compositions suitable for use in producing polyurethane 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 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 the mixture of a polyol sovent 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.

The polymer/polyol compositions initially introduced were primarily compositions produced from polyols and acrylonitrile and, to some extent, acrylonitrile-methylmethacrylate 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-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. 1,412,797 (Priest) describes an improved process for forming polymer/polyols from acrylonitrile-styrene monomer systems 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 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. 1,516.385) (Simroth) discloses additional and substantial improvements in forming 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 improvements in the formation of polymer/polyols. As discussed therein, polymer/polyol compositions exhibiting outstanding properties can be 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 produced on a commercial scale with polyols having a molecular weight lower than have 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 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 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 of acrylonitrile to styrene or other comonomer used in the monomer system, the minimum polyol molecular weight and the maximum polymer content when prior techniqes 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 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 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 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 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-isobutylonitrile in certain monomer-polymer 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 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 azobis-isobutyronitrile when used as the initiators in the in situ polymerisation of acrylonitrile in a propylene oxide triol having a theoretical number average molecular weight of 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 used in forming polymer/polyols. United States Patents No. 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 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 test, "Dispersion Polymerization in Organic Media", edited by K. E. G. Barrett, John Wiley & Sons, 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 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.

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 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 "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 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, 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 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 liquid as dispersion mediums which have extremely low viscosities, e.g.-typically no more than a few centipoises at 250C. The theoretical considerations discussed in Napper, Journal of Colloid and Interface 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 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 techniques, are characterized by stability satisfactory to allow commercial production and use of one or more of the following characteristics: (1) higher amounts of styrene or other comonomer when acrylonitrile copolymer polymer/polyols are being prepared, (2) higher polymer contents or (3) the use of low molecular weight polyols. The particular dispersant employed and the 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 dispersion polymerization in which the primary focus is directed to designing stabilizers based upon the relative solubility and insolubility of the solvatable 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 utilized in producing the dispersed phase (i.e.-the polymer).

The stabilizers used in the present invention are described and claimed in copending British Patent Application No. 7942510, (Serial No. 1,598,930).

The present invention is thus directed to a-process for producing a fluid, stable polymer/polyol composition which comprises: adding a preformed stabilizer, which is a graft or addition copolymer of (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 the other of the said monomers is capable of forming a polymer which is soluble in the monomer from which it is formed, and (b) a solvatable portion consisting of a propylene oxide polymer having a number average molecular weight of at least 800, the said preformed stabilizer having a viscosity in excess of 40,000 centipoises at 25"C, to a normally liquid polypropylene oxide polyol having a number average molecular weight of at least 400 and a hydroxyl number of from 20 to 280, the said preformed stabilizer being present in the polyol in an amount sufficient to stabilize the subsequently formed polymer particles dispersed therein against phase separation, in order to provide a homogeneous mixture of the preformed stabilizer and the polyol, and subsequently polymerizing a reaction mixture comprising (I) the said homogeneous mixture of preformed stabilizer and polyol, (II) from 10 to 40 weight percent of an ethylenically unsaturated monomer or a mixture of such monomers, the said weight percent being based on the total weight of the monomer or monomer mixture and the polyol in the homogeneous mixture, and (III) a free radical catalyst, wherein the structure and the relative proportions of the monomers used for (a) and for (II) and the relative proportions of (a) and (b) are so chosen that a fluid, stable polymer/polyol composition is obtained.

Conceptually, the monomers used in preparing the polymer/polyols can comprise any ethylenically unsaturated monomer or monomers. Suitable monomers are disclosed in the Stamberger patents, previously referred to.

Representative useful monomers include acrylonitrile, styrene, vinyl acetate, ethyl acrylate, methyl methacrylate and acrylic acid. The selection of the monomer or monomers used will depend on considerations such as the relative cost of the monomers and the product characteristics required for the intended application.

It is preferred to utilize acrylonitrile or mixtures thereof with a comonomer.

When monomer mixtures are employed, it is preferred to maintain a minimum of from 5 to 15 percent by weight acrylonitrile in the system. Styrene will generally be preferred as the comonomer, but methyl methacrylate or other monomers may be employed in place of part or all of the styrene. To provide polymer/polyols for use in applications where minimal scorch is desired, the acrylonitrile content of the monomer mixture used should be less than about 40 percent by weight, preferably less than about 30 percent.

The polymer content of the polymer/polyol can vary within wide limits, depending upon the requirements of the anticipated end use application.

Conceptually, it will in general be desirable to form the polymer/polyols with as high a polymer content as will provide the desired viscosity and stability properties.

In general, this will vary from 10 to 60 percent, based upon the weight of the polymer/polyol. Lower polymer contents may, of course, be utilized: however, there is typically no incentive to use monomer amounts which will result in polymer contents lower than 10 percent by weight because of the lower conversions and the economic penalty due to the increased throughput involved. On the other hand, it will generally be undesirable to utilize polymer contents in excess of 40 percent by weight. While useful polymer/polyols with higher polymer contents certainly can be made, these polymer/polyols may possess viscosity and stability characteristics which are commercially undesirable.

The resulting polymer/polyols may, if desired, be blended with conventional polyols to reduce the polymer content to the level required for the particular end use application. Blends in which the resulting polymer content is as low as 4 percent of the total weight of the blend or even less are useful.

With respect to the polyol constituent, this is a normally liquid polypropylene oxide polyol and will include the poly(oxypropylene) glycols, triols and higher functionality polyols. These polyols include poly(oxypropyleneoxyethylene) polyols; however, desirably, the oxyethylene content should comprise less than 50 percent of the total and, preferably, less than 20 percent. The ethylene oxide can be incorporated in any fashion along the polymer chain. Stated another way, the ethylene oxide can be either incorporated in internal blocks as terminal blocks, or may be randomly distributed along the polymer chain. As is well known in the art, the preferred polyols herein do contain varying amounts of unsaturation. The extent of unsaturation typically involved does not affect in any adverse way the formation of the polymer/polyols in accordance with the present invention.

For purposes of this invention, useful polyols have a number average molecular weight of about 400 or greater, the number average being used herein being the theoretical, hydroxyl number derived value. The true number average molecular weight may be somewhat less, depending upon the extent to which the true molecular functionality is below the starting or theoretical functionality.

The polyols employed can have hydroxyl numbers which vary over a wide range. In general, the hydroxyl numbers of the polyols employed in the invention range from 20 to 280. The hydroxyl number is defined as the number of milligrams of potassium hydroxide required for the complete hydrolysis of the fully phthalylated derivative prepared from 1 gram of polyol. The hydroxyl number can also be defined by the equation: 56.1 x-1000xf OH m.w. where OH-=hydroxyl number of the polyol, f=functionality, that is, average number of hydroxyl groups per molecule of polyol, m.w.=molecular weight of the polyol.

The exact polyol employed depends upon the end use of the polyurethane product to be produced. The molecular weight or the hydroxyl number is selected properly to result in flexible or semi-flexible foams or elastomers when the polymer/polyol produced from the polyol is converted to a polyurethane. The polyols preferably possess a hydroxyl number of from 50 to 150 for semi-flexible foams and from 30 to 70 for flexible foams. These limits are not intended to be restrictive, but are merely illustrative of the large number of possible combinations of the above polyol coreactants.

Regarding the catalyst employed to form the polymer/polyols, any free radical catalyst, from the conceptual standpoint, may be utilized. Useful catalysts include the t - alkyl peroxyester catalysts described in the hereinbefore mentioned, copending British Patent Application No. 28713/76, (Serial No. 1,559,121). As described therein, useful catalysts must have a satisfactory half-life within the temperature ranges used in forming the polymer/polyol compositions, i.e.-the half-life should be about 25 percent or less of the residence time in the reactor at a given temperature. Representative examples of useful catalyst species include t butyl peroxy - 2 - ethylhexanoate, t - butylperpivalate, 2,5 - dimethyl - hexane 2,5 - di - per - 2 - ethyl hexoate, t - butylperneodecanoate, t - butylperbenzoate and di - t - butylphthalate. It is, however, preferred to employ azo catalysts, with azobis-isobutyronitrile being preferred. In general, it is believed that the azo catalyzed polymer/polyols process better in the preparation of urethane flexible foams. Thus, the use of these catalysts will generally provide lower acidity in the resulting polymer/polyols as well as freedom from the odor characteristic of products formed with peroxyester catalysts which might be objectionable to some users.

The catalyst concentration employed is not critical and can be varied within wide limits. As a representative range, the concentration can vary from 0.1 to 5.0 weight percent or even more, based upon the total feed to the reactor. Up to a certain point, increases in the catalyst concentration result in increased monomer conversion: but further increases do not substantially increase conversion. The particular catalyst concentration selected will usually be an optimum value considering all factors, including costs.

The polymer/polyols of the present invention are preferably produced by utilizing the process set forth in British Patent Specification No. 1,412,797. In accordance with that process, a low monomer to polyol ratio is maintained throughout the reaction mixture during the process. This is achieved by employing conditions that provide rapid conversion of monomer to polymer. In practice, a low monomer to polyol ratio is maintained, in the case of semi-batch and continuous operation, by control of the temperature and mixing conditions and, in the case of semi-batch operation, also by slowly adding the monomers to the polyol.

The temperature range is not critical and may vary from 1000C to 140"C or perhaps greater, the preferred range being from 1150C to 125"C. As has been noted herein, the catalyst and temperature should be selected so that the catalyst has a reasonable rate of decomposition with respect to the hold-up time in the reactor for a continuous flow reactor or the feed time for a semi-batch reactor.

The mixing conditions employed are those obtained using a back mixed reactor (e.g.-a stirred flask or stirred autoclave). The reactors of this type keep the reaction mixture relatively homogeneous and so prevent localized high monomer to polyol ratios such as occur in certain tubular reactors, e.g.-in the first stages of "Marco" reactors when these reactors are operated with all the monomer added to the first stage.

The utilization of the Priest process is preferred since this allows the preparation of polymer/polyols with a wide range of monomer compositions, polymer contents and polyols that could not be otherwise prepared with the necessary requisite stability. However, whether the utilization of the Priest process is essential depends upon whether the process parameters are such that a satisfactory polymer/polyol can be prepared without using this process.

The polymer/polyols of the present invention comprise dispersions in which the polymer particles (the same being either individual particles or agglomerates of individual particles) are relatively small in size and, in the preferred embodiment. are all essentially less than about one to three microns. However, when high contents of styrene are used, the particles will tend to be larger; but the resulting polymer/polyols are highly useful, particularly where the end use application requires as little scorch as possible. In the preferred embodiment, essentially all of the product (viz.-about 99% or more) will pass through the filter employed in the filtration hinderance (filterability) test that will be described in conjunction with the Examples. This ensures that the polymer/polyol products can be successfully processed in all types of the relatively sophisticated machine systems now in use for large volume production of polyurethane products, including those employing impingement-type mixing which necessitate the use of filters that cannot tolerate any significant amount of relatively large particles. Less rigorous applications are satisfied when about 50 percent of the product passes through the filter. Some applications may also find useful products in which only about 20 percent or even less passes through the filter. Accordingly, the polymer/polyols of the present invention desirably contemplate the products in which only 20 percent pass through the filter, preferably at least 50 percent, and most preferably, essentially all.

Indeed, it should be appreciated that the filtration hindrance test presents the most rigorous test of polymer/polyol stability: and, accordingly. while satisfactory filtration hindrance characteristics are certainly to be preferred. commercially stable polymer/polyols for a variety of applications may be satisfactorily defined by their viscosity and centrifugible solids level (this test being also described in connection with the Examples). Thus, polymer/polyols are considered stable as long as the viscosity is no more than about 5000 cps at 25"C and the centrifugible solids are less than about 100,,, preferably less than 5 In accordance with the present invention, the preparation of the polymer/polyols is carried out in the presence of a preformed stabilizer tailored to the monomer system being employed. The stabilizer. in a functional sense. is present in an amount sufficient to ensure that satisfactory stabilization will result. viz.-the desired filtration hindrance. centrifugible solids level and viscosity are provided. Details of these stabilizers are given in the cited copending Application No. 7942510, (Serial No. 1,598,930).

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 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.

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 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 (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 of the monomer or monomers used for forming the dispersed polymer portion of the polymei/polyl.

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 preferably maintained 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 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 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: 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 60/4(1 acrylonitrile/styrene (line CD); Figure 2 is a tie-line diagram and illustrates the preferred anchor portion 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 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 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 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 incresed above 70 percent (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 portion composition 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 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 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 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 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 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 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 anchdr portions will correspond to 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 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 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 to stabilization achieved by a precursor technique.

It should also be appreciated that the more significant improvements in stability of the polymer/polyols in accordance with the present invention are achieved when one or more of the following parameters are present: (1) a relatively high styrene or other comonomer content (i.e.70% or more) in the acrylonitrilecomonomer system, (2) a relatively high monomer content (i.e.30% or more) and (3) a relatively low polyol molecular weight (i.e.-less than about 2000 or so). If these general parameters are not exceeded, satisfactory stabilization will generally be inherently achieved without the necessity of employing any additional technique for stabilization such as the present invention.

The present invention will accordingly find its more important utility in situations where one or more of the above-identified parameters must be utilized to form a polymer/polyol for the particular end use application. Thus, where an application requires a relatively scorch-free product such as in slab stock foam, this may be achieved by forming a polymer/polyol with reduced amounts of acrylonitrile (i.e.-less than about 40%, preferably less than 30%). Indeed, if desired, relatively stable all-styrene polymer/polyols may be formed. Similarly, where high modulus characteristics are required, the present invention allows production of stable polymer/polyols from monomer contents of 30% or more. Still further, stable polymer/polyols can be formed using polyols having molecular weight down to about 400 or so with relatively high monomer contents (up to about 37%).

The appropriate limits for the parameters capable of being used to form a stable polymer/polyol will, of course, depend on the particular stability requirements as well as the interrelationship of the parameters. Thus, when a particular acrylonitrile monomer system is being used, the maximum monomer content that may be employed decreases somewhat as the molecular weight of the polyol decreases. As a specific example, when using a 20/80 acrylonitrile/styrene monomer system, stable polymer/polyols can be made with 18 polymer content in a 3000, but not lower, molecular weight polyol. Similarly, when the objective is to utilize as high a monomer content as is possible, the particular useful maximum will be determined by the acrylonitrile/styrene or other comonomer ratio of the monomer system needed and the molecular weight of the polyol being utilized. The maximum useful polymer content will generally decrease somewhat with decreasing molecular weights of the polyol or relatively high styrene (or other comonomer) to acrylonitrile ratios. Satisfactorily stable polymer/polyols of about 400o polymer or so can be made with a 40/60 monomer system and a 3000 molecular weight polyol.

The situation is the same when low molecular weight polyols are used. Thus, whether a stable polymer/polyol can be made in a particular polyol will depend on the other two parameters desired. The present invention allows formation of stable polymer/polyols in polyols of 400 molecular weight at 379, polymer content with a 50/50 monomer system.

The present invention also provides a method for producing polyurethane products by reacting: (a) a polymer/polyol composition of this invention, (b) an organic polyisocyanate, and (c) a catalyst for the reaction of (a) and (b) to produce the polyurethane product, and, when a foam is being prepared, a blowing agent and a foam stabilizer. The reaction and foaming operations can be performed in any suitable manner, preferably by the one-shot technique.

The organic polyisocyanates that are useful in producing polyurethane products in accordance with this invention are organic compounds that contain at least two isocyanato groups. These compounds are well known in the art. Suitable organic polyisocyanates include the hydrocarbon diisocyanates, (e.g., the alkylene diisocyanates and the arylene diisocyanates) as well as known triisocyanates.

Examples of suitable polyisocyanates are 1,2- diisocyanatoethane, 1,3 diisocyanatopropane, 1,2 - diisocyanatopropane, 1,4 - diisocyanatobutane, 1,5 diisocyanatopentane, 1,6 - diisocyanatohexane, bis(3 - isocyanatopropyl)ether, bis(3 - isocyanatopropyl)sulfide, 1,7 - diisocyanatoheptane, 1,5 - diisocyanato 2,2 - dimethylpentane, 1,6 - diisocyanato - 3 - methoxyhexane, 1,8 diisocyanatooctane, 1,5 - diisocyanato - 2,2,4 - trimethylpentane, 1,9 diisocyanatononane, 1,10 - diisocyanatopropyl)ether of 1,4 - butylene glycol, 1,11 - diisocyanatoundecane, 1,12 - diisocyanatododecane bis(isocyanatohexyl)sulfide, 1,4 - diisocyanatobenzene, 2,4 - diisocyanatotoluene, 2,6 - diisocyanato tolylene, 1,3 - diisocyanato - o - xylene, 1,3 - diisocyanato m - xylene, 1,3 - diisocyanato - p - xylene, 2,4 - diisocyanato - 1 chlorobenzene, 2,4 - diisocyanato - I - nitrobenzene, and 2,5 - diisocyanato - I nitrobenzene and mixtures thereof.

The catalysts that are useful in producing polyurethanes in accordance with this invention include: (a) tertiary amines such as bis(dimethylaminoethyl)ether, trimethylamine, triethylamine, N - methylmorpholine. N - ethylmorpholine, N,N - dimethylbenzylamine, N,N - dimethylethanolamine, N,N,N',N' tetramethyl - 1,3 - butanediamine, triethanolamine, 1,4 diazabicyclo[2.2.2]octane, and pyridine oxide; (b) tertiary phosphines such as trialkylphosphines, and dialkylbenzylphosphines: (c) strong bases such as alkali and alkaline earth metal hydroxides, alkoxides, and phenoxides: (d) acidic metal salts of strong acids such as ferric chloride, stannic chloride, stannous chloride, antimony trichloride, and bismuth nitrate and chloride; (e) chelates of various metals such as those which can be obtained from acetylacetone, benzoylacetone, trifluoroacetylacetone, ethyl acetoacetate, salicylaldehyde, cyclopentanone - 2 carboxylate, acetylacetoneimine, bis - acetylacetone - alkylene - diimines, and salicylaldehydeimine, with the various metals such as Be, Mg, Zn, Cd, Pb, Ti. Zr, Sn, A, Bi, Cr, Mo, Mn, Fe, Co, Ni, or such ions as MoO,++ and UO2++, (f) alcoholates and phenolates of various metals such as Ti(OR)4, Sn(OR)4, Sn(OR)2. and Al(OR)3, wherein R is an alkyl or aryl group, and the reaction products of alcoholates with carboxylic acids, betadiketones, and 2 - (N,N dialkylamino)alkanols, such as the well known chelates of titanium obtained by the described or equivalent procedures; (g) salts of organic acids with a variety of metals such as alkali metals, alkanine earth metals, Al, Sn, Pb, Mn, Co, Ni, and Cu, including, for example, sodium acetate, potassium laurate, calcium hexanoate, stannous acetate, stannous octoate, stannous oleate, lead octoate, and metallic driers such as manganese and cobalt naphthenate; and (h) organometallic derivatives of tetravalent tin, trivalent and pentavalent As, Sb, and Bi, and metal carbonyls of iron and cobalt.

Among the organotin compounds that deserve particular mention are dialkyltin salts of carboxylic acids, e.g. dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate, dilauryltin diacetate, dioctyltin diacetate, dibutyltin - bis(4 methylaminobenzoate), and dibutyltin - bis(6 - methylaminocaproate). Similarly there may be used a trialkyltin hydroxide, dialkyltin oxide, dialkyltin dialkoxide, or dialkyltin dichloride. Examples of these compounds include trimethyltin hydroxide, tributyltin hydroxide, trioctyltin hydroxide, dibutyltin oxide, dioctyltin oxide, dilauryltin oxide, dibutyltin- bis(isopropoxide), dibutyltin - bis(2 - dimethylaminopentylate), dibutyltin dichloride, and dioctyltin dichloride.

The tertiary amines may be used as primary catalysts for accelerating the reactive hydrogen/isocyanate reaction or as secondary catalysts in combination with one or more of the above noted metal catalysts. Metal catalysts, or combinations of metal catalysts, may also be employed as the accelerating agents, without the use of amines. The catalysts are employed in small amounts, for example, from 0.001 percent to 5 percent, based on the weight of the reaction mixture.

When the product being formed is a polyurethane foam, this may be accomplished by employing a small amount of a polyurethane blowing agent, such as water, in the reaction mixture (for example, from 0.5 to 5 weight percent of water, based upon total weight of the polymer/polyol composition, or through the use of blowing agents which are vaporized by the exotherm of the reaction, or by a combination of the two methods, Examples of polyurethane blowing agents are halogenated hydrocarbons such as trichloromonofluoromethane, dichlorodifluoromethane, dichloromonofluoromethane, dichloromethane, trichloromethane, 1,1 - dichloro - 1 - fluoroethane, 1,1,2 - trichloro - 1,2,2 trifluoromethane, hexafluorocyclobutane, and octafluorocyclobutane. Another class of blowing agents include thermally unstable compounds which liberate gases upon heating, such as N,N' - dimethyl - N,N' - dinitrosoeterephthalamide. The generally preferred method of foaming for producing flexible foams is the use of water or a combination of water plus a fluorocarbon blowing agent such as trichloromonofluoromethane. The quantity of blowing agent employed will vary with factors such as the density desired in the foamed product. the anti-scorch properties of the foams produced using polymer/polyol compositions are most evident when at least some of the blowing agent is water and the water is used in an amount that results in a foam having a density less than 1.75 pounds per cubic foot.

Generally, the use of water in an amount of at least 3.0 percent by weight based on the total weight of the polymer/polyol composition results in a foam having a density of less than 1.75 pounds per cubic foot.

It is also within the scope of the invention to employ small amounts e,g., from 0.001 percent to 5.0 percent by weight, based on the total reaction mixture, of a foam stabilizer such as a "hydrolyzable" polysiloxane-polyoxyalkylene block copolymer such as the block copolymers described in United States Patents Nos.

2,834,748 and 2,917,48. Another useful class of foam stabilizer are the "nonhydrolyzable" polysiloxane-polyoxyalkylene block copolymers such as the block copolymers described in United States Patent No. 3,505,377; and British Patent Specifications Nos. 1,220,471 and 1,341,028. The latter class of copolymers differs from the above mentioned polysiloxane-polyoxyalkylene block copolymers in that the polysiloxane moiety is bonded to the polyoxyalkylene moiety through direct carbon-to-silicon bonds, rather than through carbon-tooxygen-to-silicon bonds. These various polysiloxane-polyoxyalkylene block copolymers preferably contain from 5 to 50 weight percent of polysiloxane polymer with the remainder being polyoxyalkylene polymer.

Particularly useful foam formulations utilizing polymer/polyols are well known and are being presently used commercially to form various foam products. It has been found that, when using these conventional formulations, foams made with polymer/polyols utilizing the stabilizers prepared by the technique of this invention previously described herein exhibit a tendency to collapse. It is believed that, in some unknown fashion, these polymer/polyols upset the stability of the rising foam.

This tendency can be overcome by, for example, either increasing the amount of catalyst used or by increasing the amount of the silicone or other surfactant employed.

The polyurethanes produced in accordance with this invention may be advantageously employed in various applications. For example, the present invention allows the production of polyurethane foams from polymer/polyols in which the polymer portion can be formed from a monomer system containing less than 20 to 30 percent by weight acrylonitrile. These foams find advantageous utility in the slab foam market where the cross-sections of the buns are relatively large and where a relatively large exotherm is encountered. In these situations, polyurethane foams produced in accordance with this invention result in white products with little scorch whatever being visually detectable. Still further, the polymer/polyols of this invention may be used to form polyurethane elastomers in which relatively low molecular weight polyols must be used to provide the requisite stiffness. In addition, polymer/polyols stabilized in accordance with the present invention may be utilized to form polyurethane products where maximum load bearing characteristics are required since the stabilization achieved allows the use of a relatively high polymer content.

The utilization of the technique described in copending Application No.

7942510, (Serial No. 1,598,930), to prepare the polymer/polyols of stabilizers without the initial step of forming a macromonomer results in an unexpected advantage in forming polyurethane foams. Thus, in contrast to 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.

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 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 monomer or monomers to be employed to form the polymer part of the polymer/polyol as the anchor portion, thereby requiring only tesolvent used to 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 a liquid whose viscosity will typically range from 60,000 up to 260,000 or more centipoises at 250C.

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 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 semi-solid 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 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 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 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.

The following Examples are illustrative, but not in limitation of, the present invention. These Examples describe all of the several parameters involved in preparing and using the stabilizers of the present invention, ranging from the preparation of the macromonomer used in one embodiment as the solvatable portion to screening of the parameters used to form the stabilizers to characterizing the effectiveness of the stabilizers in a variety of polymer/polyol preparations.

Because of the relative large number of parameters involved, a proper evaluation of the data contained requires a careful consideration of all of these parameters.

The Examples should therefore be considered together, presenting a trend showing useful parameters and stabilizers for various polymer/polyol preparations. Thus, as one example, the amount of stabilizer used must be scrutinized. A level of lOo by weight provides an indication of the effectiveness of the stabilizer: but the use of increased amounts, consistent with this invention, will enhance stability.

As used in the Examples appearing below, the following designations, symbols, terms and abbreviations have the indicated meanings: "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.

"rpm" denotes revolutions per minute.

"mg" denotes milligrams.

"A" denotes acrylic acid.

"MMA" denotes methylmethacrylate.

"MA" denotes methacrylic acid.

"TBPO" denotes t - butyl per - 2 - ethylhexoate.

"AZO" denotes 2,2' - azobisisobutyronitrile.

"TMSN" denotes tetramethylsuccinonitrile.

"pcf" denotes pounds per cubic feet.

"Sol" denotes solution.

"S" denotes solid.

"%" denotes percent by weight.

"wt" denotes weight.

"Ratio" denotes weight ratio.

"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 propylene oxide and butanol having a number average molecular 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 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.

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

"Polyol II"-a polypropylene oxide diol produced from propylene oxide and dipropylene glycol and having a theoretical number average molecular weight of about 400.

"Polyol III"-a polypropylene oxide diol produced from propylene oxide and dirpopylene glycol and having a theoretical number average molecular weight of about 1000.

"Polyol IV"-a polypropylene oxide triol having about 34% internal ethylene oxide content, a hydroxyl number of about 46,6 and having a number average molecular weight of about 3600-.

"Polyol V"-a propyoxylated/ethoxylated polyol having a hydroxyl number of about 56 mg. KOH/gm, an internal ethylene oxide content of about 8%, and a number average molecular weight of about 3000.

"Urethane Catalyst"-a solution consisting of 70% Bis (2 - dimethylaminoethyl) ether and 30% dipropylene glycol.

"Silicone Surfactant I-a mixture of 55 wt.-% of a block copolymer having the formula: Me3SiO(Me2MiO)72 (MeSiO)5.1SiMe3 -C3H6(OC2H4)24(OC3H6)27OMe where Me denotes the methyl group; and 45 wt.- of a polyether having the formula: C4H9O(C2H4O)1a(C3H6O)13.7H "Silicone Surfactant II"-a mixture of 80 wt.-% of the above block copolymer and 20 wt.-% of the above polyether.

Polymer/Polyol Properties Filtration Hindrance (Filterability) This is determined by diluting a sample (470 grams) of polymer/polyol with anhydrous isopropanol (940 grams) to remove any viscosity-imposed limitations and using a fixed quantity of material in relation to a fixed cross-sectional area of screen (2.4 sq. in.) such that about 200 grams of product are passed through 150 or 700-mesh screen per one square inch of screen. The 700-mesh screen is made with a Dutch twill weave. The actual screen used had a nominal opening of 30 microns and is described in Bulletin 46267-

Refractometer Using an IDL color eye model no. Dl, made by Kollmorgen Corp., Attleboro, Mass.. a numerical rating of from 0 to 100 is made on the test specimen by comparison to a series of standards. A rating of "100" corresponds to a specimen rated as being white.

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 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 Oldershaw column with decanting still head. The mixture was refluxed for from about 8 to about 12 hours at a temperature in the range of from about 80 to about 1 10"C., and the water from the reaction was collected. The product was then neutralized at 50"C. 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 1000C. to remove the salt (e.g.- sodium p-toluene sulfonate or sodium sulfate).

Preparation of Dispersant of 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.

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, 3050 monomer or monomers/5W70 macromonomer or polypropylene oxide 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.

Polymer/Polyol Preparation Unless otherwise indicated, the polymer/polyols were prepared by adding the polyol to a l-liter, 4-necked flask equipped with a stirrer (Lightnin Stirrer), dropping funnel, water-cooled condenser, nitrogen inlet and outlet. The flask and contents were heated to the temperature desired, and part of the free radical catalyst employed added. The monomer mixture being utilized with additional amounts of the free radical catalyst employed where then added dropwise from the dropping funnel over a period of about 45 minutes with continuous rapid stirring.

The mixture was stirred at a high rate of speed initially, viz.-as fast as possible without excessive splashing, until about 1/2 of the monomer mixture had been added. At this time, the stirring was increased again as much as possible without causing excessive splashing. After completion of monomer addition, the reaction mixture was heated and stirred for about an additional hour. In some cases, a slight temperature rise was noted; and, in most cases, no attempt was made to prevent such temperature increase. The samples were then cooled, and a small amount taken for free monomer analysis by gas chromatography. Also, unless other wise indicated, the weight ratio of monomer mixture to polyol used was 20/80.

EXAMPLES 1-7 These Examples illustrate the preparation of macro-monomers using 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 parameters are set forth in Table l: TABLE 1

Example No. 1 2 3 4 5 6 7 Polypropylene oxide I II III # IV V material, type gms. 3000 # Unsaturated acid, type MA A MA A A A A gms. 385 127 120 100 100 54 46 Solvent, type Benzene Toluene Benzene Benzene Toluene Benzene Benzene gms. 735 # Monomethyl ether 0.15 1.0 0.6 0.6 0.6 1 1 hydroquinone, gms (1) 2,6-dimethyl 2,4,6- 5 - 5 5 5 5 octatriene, gms. (10 p-touene sulfonic acid, 50 - - - - - gms. (2) sulfuric acid gms. (2) - 36 # (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 2428 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 8-10 which were polymerized at 900 C. and Example 11 wherein the polymerization was carried out at 800C. The procedure for Example 19 was carried out at 1000C. 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: TABLE II

Example No. 8 9 10 11 12 13 14 15 16 17 Macomonomer Polypropylene oxide material III 2 # Unsaturated acid MA # Stabilizer Solvent (1) Tol Tol Tol Ben Tol Tol E Ben Tol Tol Tol/MEK Ratio acrylonitrile to 30/70 30/70 30/70 30/70 30/70 30/70 30/70 15/18 85/15 30/70 styrene monomer %Solids (2) 27.5 27.7 25.7 31.7 45.5 47.1 27.4 25.2 31.9 26.1 %Vinyl content Reactants(3) 50 50 70 50 50 30 50 50 50 50 Stabilizer (NMR) (4) 41.6 38.1 54 34.8 44.5 26.2 38.7 33.7 33 38.3 Catalyst TBPO AZO TBPO # Stabilizer Properties After standing (5) SS C C NS NS SS SS NS NS(6) SS Solubility in Polyol I Good Poor Poor Good V.Poor V.Good Good Good Good Good Stability ability (7) Good Poor Poor Good Poor V.Good Poor Poor Poor Poor TABLE II (continued)

Example No. 18 19 20 21 22 23 24 25 26 27 28 Macromonomer Polypropylene oxide material III # I # Unsaturated acid MA None MA MA A A MA Stabilizer Solvent (1) Polyol I Tol # Ratio acrylonitrile to styrene monomer 30/70 30/70 72/25 30/70 30/70 30/70 30/70 30/70 30/70 30/70 30/70 %Solids (2) - 28.5 32.7 28.6 29.1 29.9 28.7 30.9 28.8 31.3 36.1 %Vinyl content Reactants (3) 50 50 50 40 50 40 50 30 70 20 30 Stabilizer (NMR) (4) - 40.9 34.2 32.6 45.4 34.5 52 32.7 67.4 26.4 33.4 Catalyst TBPO # Stabilizer Properties After standing (5) NS C NS(2) NS NS NS NS NS NS NS NS Solubility in Polyol I Good Good Good Good Good Good Poor Good Poor Good Good Stailizing ability (7) Poor Poor Poor Good Poor Good Poor Poor Poor Fair Fair 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 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.

(5) SS-a slight settling of a small amount of polymer out of the solution.

C-stabilizer separated into a upper and lower 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 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 concentration of 3O50% vinyl monomer is desirable.

EXAMPLES 29-35 These Examples demonstrate the preparation of additional useful stabilizers with polypropylene oxide materials having molecular weights ranging from about 800 to about 5000 and with anchor portions wherein the acrylonitrile/styrene ratio 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: TABLE III

Example No. 29 30 31 32 33 34 35 Macromonomer Polypropylene oxide IV V II III # Unstaurated acid A A A A A None None Stabilizer Solvent Toluene Toluene Toluene Toluene Toluene Xylene Xylene Ratio acrylonitrile to 27/75 30/70 30/70 50/50 45/55 45/55 50/50 styrene monomer %Solids(1) - 29 30.8 30 31.3 47.6 46.0 Vinyl Content of 20.6 45 40 40 40 50 34 Reactants (2) Catalyst TBPO TBPO TBPO TBPO TBPO TBPO TBPO Polymerization Temperature 100 100 100 100 104 130 130 Stabilizer Properties Solubility in Polyol I Good Good Good Good Good Good Good Stabilizing A bility (3) Good Good Poor Good Good Good Good (1) Solids refers to the residue that remains when solvent is evaporated from stabilizer solution.

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

(3) Examples 29-31 evaluated with a polymer/polyol formed from an acrylonitrile/styrene monomer weight ratio of 40/60 while Examples 3235 were evaluated using a somewhat higher styrene content in the monomer ratio (e.g.-about 30/70).

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 36-98 These Examples illustrate the preparation of polymer/polyol using various stabilizers.

The polymer/polyols were prepared in Polyol I with a monomer content of 20O,o/ by weight of 40/60 acrylonitrile/styrene using an azo catalyst. For comparison purposes, the acrylonitrile/styrene ratio was varied in selected Examples. The preparation of the polymer/polyols and the properties of the resulting products are summarized in Tables IV-VIII: TABLE IV Example No. 36 37 38 39 40 41 42 43 44 45 46 47 48 Preparation Reaction Temperature 110 110 110 110 110 110 110 110 110 110 110 110 110 AZO Conc., Wt.% 1.3 1.3 1.3 1.3 1.3 0.98 0.98 0.98 0.98 1.3 2.4 1.3 1.3 % Monomer 20 20 20 20 20 20 20 20 20 20 20 20 20 A/S Ratio 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 Stabilizer composition, from Ex. No. 8 9 10 11 13 17 15 16 14 8 8 8 10 Wt. % Solid Stabilizer 0.62 0.62 0.33 0.75 0.74 0.62 0.6 0.75 0.65 0.65 0.65 0.65 0.65 Monomer Feed Rate, gm/hr 65 60 60 65 60 60 60 60 60 70 70 70 Residual Acrylonitrile, % 0.27 0.48 .25 0.08 0.23 0.33 0.31 0.30 0.31 - 0.25 0.29 0.34 Residual Stryrene, % 0.27 0.39 .26 0.05 0.2 0.29 0.29 0.32 0.23 - 0.24 0.31 0.42 Residual TMSN, % - - - - - - - - - 0.03 - Residual Toluene, % - - - - - - - - - - - Residual Benzene, % - - - - - - - - - - - Copnversion, Acrylonitrile, % 96.5 94.0 96.8 99.0 97.1 95.8 96.1 96.2 96.1 - 96.8 96.4 95.7 Conversion, Styrene, % 97.7 96.7 97.8 99.5 98.3 97.6 97.6 97.3 98.0 - 98.0 97.4 96.5 Conversion, Combined,% 97.2 95.6 97.4 99.4 97.8 96.9 97.0 96.9 97.2 - 97.0 97.0 96.1 Total Polymer in Product, Calc. % 19.2 18.9 19.2 19.6 19.4 19.2 19.2 19.2 19.2 - 19.2 19.2 19.0 Properties Viscosity (Brookfield)25 C., cps. 1,320 1,808 2,828 1,272 1,696 3,000 3,100 - 7,480 3,860 6,400 1,580 1,712 Acid No. (Experimental) 0.0044 0.0045 0.0053 0.0053 0.0053 0.0053 0.0065 0.0070 0.0065 - - - Hydroxyl No. (Experimental) - - - - - - - - - - - filtration Hindrance: 150 Mesh Screen, % Thru. 100 - - 100 100 - - - - - - - 1.5 Solids on Screen, ppm 25 - - 13.5 6.3 - - - - - - - 21.311 700 Mesh Screen, Time, > 1200 - - > 1200 > 1200 - - - - - - - 700 Mesh Screen, % Thru. 17.1 - - 46.6 66.6 - - - - - - - Solids on Screen, ppm 122.7 - - 87.9 22.5 - - - - - - - Centrifugible Solids (Wt.%) 1.28 4.27 16.3 1.21 1.30 6.83 16.42 31.96 33.65 14.13 14.49 3.43 6.96 TABLE V Example No. 49 50 51 52 53 54 55 56 57 58 59 60 61 Preparation Reaction Remperature 110 110 110 110 110 110 110 110 80 80 95 95 110 AZO Cone. Wt. % 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 % Monomer 20 20 20 20 20 20 20 20 20 20 20 20 18 A/S Ratio 40/60 40/60 40/60 20/80 0/100 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 Stabilizer composition, from Example No. 11 13 13 8 8 8 8 8 8 8 8 8 8 Wt. % Solid stahbilizer 0.65 0.65 0.65 0.65 0.65 0.65 1.29 0.17 0.65 0.65 0.65 1.30 1.3 Monomer fee Rate, gm/hr 70 70 70 70 70 70 70 75 45 90 90 60 52 Residual Aerylonitrile,% 0.08 0.22 0.33 0.07 - 0.29 0.24 0.33 0.41 0.16 0.12 0.15 0.24 Residual Styrene, % 0.09 0.24 0.30 1.27 3.07 0.23 0.30 0.32 0.04 0.08 0.08 0.14 0.24 Residual TMSN, % - - - - 0.02 0.05 0.61 0.76 0.7 0.56 0.32 0.56 0.49 Residual Toluene, % - - - - - - - - - 1.44 0.05 2.88 2.7 Residual Benzene, % - - - - - - - - - 0.08 1.09 0.14 0.05 Conversion, Aerylonitrile, % 99.0 98.4 95.8 99.1 - 96.4 98.7 95.8 94.8 96.7 98.5 98.2 96.8 Conversion, Styrne,% 99.2 98.0 97.5 92.0 84.4 98.1 97.5 97.3 99.7 99.3 99.3 98.9 97.4 Conversion, Combined, % 99.0 97.7 96.8 93.3 84.4 97.4 97.2 96.6 97.7 98.3 99.0 98.5 97.3 Total Polymer in Product, Calc. % 19.6 19.0 19.2 18.4 16.7 19.2 19.2 19.1 19.3 19.4 19.3 19.4 17.3 Properties Viscosity (Brookfield 25 C., cps. 2,800 7,750 9,700 1,130 1,140 6,150 2,950 2,688 8,700 10,400 11,300 3,270 1,224 Acid No. (Experimental) - - - - 0.0181 - - - - - 0.0102 - Hydroxy No. (Experimental) - - - - 43.56 - - - - - 43.41 - Filtration Hindrance: 150 Mesh Scree,% Thru 4.5 - - 5.3 100 - - 1.8 - - 0.5 3.0 6.5 Solids on Screen, ppm 2.504 - - 3,256 897 - - 5,734 - - 65,395 2,709 2,853 700 Mesh Screen, Time, Sec. > 1200 - - > 1200 > 1200 - - - - - - > 1200 > 1200 700 Mesh Screen, % Thru 0.2 - - 0.4 14.7 - - - - - - 0.08 2,8 Solids on Screen, ppm 19.737 - - 5,207 3.664 - - - - - - 24,375 2,117 Centrifugible Solids, Wt.% 4.95 17.42 47.06 7.19 25.87 25.63 5.71 10.13 72.26 75.39 28.43 6.74 2.40 TABLE VI Example No. 62 63 64 65 66 67 68 69 70 71 72 73 74 Preparation Reaction Temperature 110 110 110 115 115 110 110 110 110 110 120 120 120 AZO Conc. Wt.% 0.71 0.71 0.71 0.71 0.71 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 %Monomer 20 20 20 20 20 20 20 20 20 20 20 20 20 A/S Ratio 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 Stabilizer composition, Example No. 11 11 11 11 11 11 11 13 22 22 22 13 21 Wt. % Solid stabilizer 1.5 1.5 1.5 1.5 0.72 1.5 1.4 1.3 1.4 1.4 1.4 1.3 1.4 Monomer Fee Rate, gm/hr 65 65 75 60 60 120 120 120 120 120 150 150 104 Residual Acrylonitrile, % 0.19 0.25 0.25 0.22 0.27 0.23 0.24 0.20 0.20 0.17 0.30 0.34 0.35 Residual Styrene, % 0.19 0.25 0.22 0.21 0.26 0.17 0.22 0.25 0.25 0.17 0.23 0.25 0.22 Residual TMSN,% 0.23 0.25 0.18 0.18 0.17 0.35 0.65 0.65 0.65 0.42 0.49 0.49 0.46 Residual Toluene,% 0.01 - - - - - - 1.14 1.14 2.14 2.90 1.2 2.95 Residual Benzene,% 1.90 1.72 2.39 2.24 1.31 2.34 2.05 0.05 0.05 0.05 0.06 0.05 0.05 Conversion, Acrylonitrile,% 97.9 96.8 96.8 97.3 96.6 97.1 97.0 97.4 97.4 97.8 96.1 95.7 95.5 Conversion, Styrene, % 97.6 97.8 98.1 98.2 97.8 98.6 98.1 97.8 97.8 98.6 98.0 97.7 98.1 conversion, Combeine,% 981. 97.5 97.6 97.9 97.0 98.0 97.6 907.7 97.7 98.3 97.3 96.9 97.1 Total Polymerin Product, Calc. T 19.2 19.2 19.1 19.3 19.1 19.2 19.2 19.2 19.2 19.3 19.1 19.0 19.1 Properties Viscosity (Brookfield) 25 C., cps. 2,304 13,00 3,6500 2,920 3,770 1,220 1,240 1,212 1,110 1,364 1,320 1,108 1,166 Naci No. (Experimental) - - - - - 0.0129 - 0.0065 0.0114 - 0.0114 0.0106 0.0442 Hydroxyl No. (Experimental) - - - - - 42.49 - 42.49 42.70 - 42.70 42.49 43.04 filtration Hindrance: 150 mesh Screen, % Thru 14.7 - - 4.0 1.0 100 100 100 11.9 5.79 11.9 100 100 Solids on Screen, ppm 153 - - 341 34.965 40.8 28.5 2.4 5,530 11.906 5,530 17.4 33.3 700 Mesh Screen > 1200 - - > 1200 - > 1200 > 1200 2314 > 1200 > 1200 > 1200 334 610 700 Mesh Screen, % Thru 1.4 - - 0.3 - 47.1 46.0 100 3.0 2.14 3.0 100 100 Solids on Screen, ppm 1.138 - - 10.700 - 47.7 20.4 18 1,725 3.266 1,725 110 54 Centrifugible Solids (Wt. %) 2.10 62.65 4.01 4.36 13.38 1.03 1.06 1.08 1.65 2.12 1.45 0.43 0.56 TABLE VII Example No. 75 76 77 78 79 80 81 82 83 84 85 86 Preparation Reaction Temperature 120 120 120 120 120 120 120 120 120 120 120 120 AZO Conc. wt. % 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 %Monomer 20 20 20 20 20 20 20 20 20 20 20 20 A/S Ratio 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 Stabilizer commostion, from Ex. No.23 18 20 15 (1) None 21 21 Onon Noe (2) 21 Wt. % Solid stabilizer 1.4 4.2 1.4 1.4 1.3 0 1.4 1.4 0 0 0.52 0.7 Monomer Fee Rate, gm/hr 112 112 150 112 112 112 112 112 112 112 112 112 Residual Acrylonitrile, % 0.38 0.45 0.56 0.58 0.28 0.46 0.58 0.45 0.32 0.26 0.29 0.38 Residual Styrene, % 0.26 0.37 0.27 0.21 0.28 0.31 0.33 0.20 0.29 0.12 0.32 0.30 Residual TMSN,% 0.53 0.56 0.72 0.56 0.40 0.47 0.68 0.49 0.58 0.48 0.49 0.54 Residual Toluene,% 3.02 - 2.86 3.83 - - 3.10 3.28 - - - 1.37 Residual Benzene,% 0.06 0.08 0.12 0.10 0.05 0.05 0.16 0.13 0.09 0.06 0.05 0.05 Conversion, Acrylonitrile,% 95.1 94.3 94.1 92.5 96.4 94.1 92.1 94.3 95.9 96.7 96.3 95.1 Conversion, Styrene, % 97.8 96.9 97.7 98.2 97.6 97.4 97.2 98.3 97.5 99.0 97.3 97.5 conversion, Combeine,% 96.7 95.8 96.3 95.9 97.1 96.1 95.4 96.7 96.9 98.1 96.9 96.5 Total Polymerin Product, Calc. % 19.0 19.0 18.9 18.8 19.1 18.9 18.7 19.0 19.0 19.2 19.0 19.0 Properties Viscosity (Brookfield) 25 C., cps. 1.154 1.400 2.970 2.80 1.688 2.990 1,060 1,122 3,060 3,260 1,400 1,120 Naci No. (Experimental) - - - - - - - - 0.0108 0.0104 0.0093 Hydroxyl No. (Experimental) - - - - - - - - 40.07 39.24 39.45 filtration Hindrance: 150 mesh Screen, % Thru 100 4.47 - - 15.6 4.7 100 100 2.0 0.83 100 100 Solids on Screen, ppm 18.9 1,969 - - 185.7 65,014 26.4 26.4 2,500 28,080 43,5 15 700 Mesh Screen, Time, Sec. 340 > 1200 - - > 1200 - > 1200 > 1200 - - 263 > 1200 700 Mesh Screen , % Thru 100 0.92 - - 0.40 - 38.2 38.2 - - 7.9 15.5 Solids on Screen, ppm 33.3 10.127 - - 7.639 - 72 72 - - 273 1600 Centrifugible Solids (Wt. %) 0.54 4.01 25.76 5.10 3.31 9.52 0.09 0.75 16.21 - 1.03 1.07 (1) macomonomer comprises a polyprophene oxide-butanaol adduct of about 2600 mol. wt. condensed with acrylic acid to provide monoethylenic terminal unsaturation and was used as a stabilizer precrsor, Viz-was added to the polyol to form the stabilizer in situ during the preparation of the polymer/polyol.

(2) Crude stabilizer was refined to tempve unreaceed momer and macromomoer, TABLE VIII Example No. 87 88 89 90 91 92 93 94 95 96 97 98 Preparation Reaction Temperature 120 120 120 120 120 120 120 120 120 120 120 120 AZO Conc. wt. % 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 %Monomer 20 20 20 20 20 20 20 20 20 20 20 20 A/S Ratio 40/60 40/60 40/60 40/60 40/60 80/20 42/58 0/100 40/60 40/60 40/60 40/60 Stabilizer commostion, from Ex. No.23 23 10 (1) (1) 23 23 25 14 16 17 Wt. % Solid stabilizer 0.39 0.17 1.4 2.6 3.8 1.4 1.4 2.6 1.4 1.4 Monomer Fee Rate, gm/hr 112 1 75 102 102 123 97 75 100 100 100 100 Residual Acrylonitrile, % 0.36 0.21 0.34 0.39 0.24 0.67 0.38 0.02 0.56 0.31 1.22 0.61 Residual Styrene, % 0.24 0.23 0.23 0.26 0.23 0.03 0.25 3.6 0.23 0.21 0.22 0.44 Residual TMSN,% 0.56 0.50 0.46 0.58 0.58 0.53 0.43 0.40 0.42 0.49 0.49 0.56 Residual Toluene,% 0.79 0.35 0.05 - - 3.03 3.07 2.96 3.29 3.93 3.12 Residual Benzene,% 0.05 0.04 2.88 0.08 0.05 0.06 0.4 0.13 0.06 0.05 0.06 Conversion, Acrylonitrile,% 95.4 97.3 95.7 95.0 96.7 91.5 95.1 - 93.0 96.0 84.0 92.3 Conversion, Styrene, % 97.9 98.0 98.0 97.8 98.0 99.7 97.8 81.5 98.0 98.2 98.2 96.5 conversion, Combeine,% 96.9 97.8 97.1 96.7 97.6 96.4 96,8 81.5 96.0 97.3 92.7 96.9 Total Polymerin Product, Calc. % 19.1 19.2 19.1 19.0 19.2 18.9 19.0 16.0 18.8 19.0 18.1 19.0 Properties Ligt Transmission % 77.1 77.8 - 67.2 71.6 93.9 86.5 55.0 70.4 - 72.1 94.9 Viscosity (Brookfield) 25 C., cps. 1,184 1,452 1,248 1,460 1,472 2,480 1,066 1,182 1,178 3,650 1,180 1,248 Naci No. (Experimental) - - - - - - - - - - - Hydroxyl No. (Experimental) - - - - - - - - - - - Filtration Hindrance: 150 mesh Screen, % Thru 100 27.2 49 49.2 82 100 100 0.83 100 0.33 100 100 Solids on Screen, ppm 19.8 13.2 48 48.6 19 28 - - 18 - - 26 700 Mesh Screen, > 1200 > 1200 > 1200 > 1200 > 1200 488 > 1200 - > 1200 - > 1200 309 700 Mesh Screen , % Thru 9.33 1.33 1.7 1.67 4 100 62 - 20 - 32 100 Solids on Screen, ppm 455 4.388 2,610 2,610 1,425 43 88 - 228 - - 129 Centrifugible Solids Wt. % 1.12 2.4 1.6 1.95 0.9 1.2 1.0 21.4 1.2 52.4 0.8 0.8 (1) macomonomer comprises a polyprophene oxide-butanaol adduct of about 2600 mol. wt. condensed with acrylic acid to provide monoethylenic terminal unsaturation and was used as a stabilizer precrsor, While an anchor portion formed from an acrylonitrile/styrene ratio of 30/70 provided effective stabilization for polymer/polyols made with a 40/60 acrylonitrile/styrene ratio (See, e.g.--Example 75), this composition stabilizer was considerably less effective when used with polymer/polyols made with styrene (See Example 94). It can also be seen from a comparison of Example 75 with Examples 90 and 91 that precursors provided less effective stabilization than can be achieved with preformed stabilizers.

EXAMPLES 99105 These Examples show the preparation of polymer/polyols in 400 molecular weight polyol (Polyol II), using stabilizers in accordance with the present invention.

The results are set forth in Table IX: TABLE IX Examle No. 99 100 101 102 103 104 105 Preparation Reaction Temperature, C, 120 120 120 120 120 120 120 Wt. % AZO 1.3 1.3 1.3 1.3 1.4 1.3 1.3 Wt.% Monomer 20 20 20 20 20 40 20 20 Ratio of Acrylonitrile to Styrene 40/60 40/60 40/60 50/50 50/50 80/20 80/20 Stabilizer (1), from Example No. 21 21 21 21 21 21 20 Wt. % 5 2.5 1.3 2.1 4.76 2.5 2.5 Ratio Anchor Part, A/S 30/70 30/70 30/70 30/70 30/70 30/70 75/25 Monomer Feed Rate, gm/hr 100 100 100 100 70 100 100 Residual Acrylonitrile 1.23 0.98 1.0 1.26 0.33 1.67 0.21 Residual Stryrene 0.37 0.41 0.41 0.15 0.20 0.04 0.32 Residual TMS 0.36 0.49 0.55 0.40 0.84 0.41 0.23 Residual Toluene - - - - - - Residual Benzene 0.05 0.05 0.05 0.05 0.06 0.04 1.14 %Conversion Acrylonitrile 84.3 87.7 87.2 97.2 98.2 89.3 98.5 %Conversion Styrene 96.9 96.7 96.7 98.5 99 98.7 92 %Conversion Combined 91.8 93.1 92.9 92.8 98.6 91.2 97.2 Total Polymer in Product, calc. % 17.8 18.5 18.5 18.5 37.4 17.7 18.9 properties Polymer Polyol Stabilit (inspection) (2) good fair good good fair poor poor Viscosity (Brookfield), cps 228 193 163 185 1020 - Filtration Hindrance: 150 Mesh Screen, % Thru 100 23 100 48 4.8 - Solids on Screen, ppm 13 21.978 29 11.110 124.023 - 700 Mesh Screen, Time sec. 125 > 1200 > 1200 > 1200 - - % Thru 100 13 9 5.2 - - Solids on Screen ppm 62.4 13.091 139 86.100 - - Centrifugible Solids, wt. %2.2 18.3 11.8 20.6 16.5 - (1) Slvent was stripped from stabilizer prior to addition to Polyol II.

(2) The product was visually inspected and subjectively evaluated in terms of settling, viscosity und pourability. A rating of "good" indicates that the product was non-setting with sufficiently low viscosity as to be pourable, while a rating of "Poor" indicates that the product was wither subject to settling of the dispersed polymer phase or was of a viscosity such that the product was not pourable. A "fair" rating indicates that the product exhibited characteristics intermediate a "poor" and "good" product.

As can be seen from Examples, extremely stable polymer/polyols at about 20 percent polymer content can be formed in a low molecular weight polyol.

EXAMPLES 106-113 These Examples illustrate the preparation of polymer/polyols in Polyol III, which has a molecular weight of about 1000, using preformed stabilizers.

The results are set forth in Table X: TABLE X Example No. 106 107 108 109 110 111 112 113 Preparation Reaction Temperature, C. 120 120 120 120 120 120 120 120 Wt.% AZO 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 Wt.% Monomer 20 20 20 40 20 20 20 20 Ratio of Acrylonitrile to Styrene 40/60 40/60 50/50 50/50 80/20 80/20 75/25 50/50 Stabilizer, from Expample No. 21 21 21 21 20 20 20 20 Solids (s) or Solution (sol) (1) sol sol(2) s s sol sol sol s Wt. % 1.3 3.5 2.1 4.76 1.3 1.3 1.3 2.5 A/S ratio Anchor Part 30/70 30/70 30/70 30/70 30/70 75/25 75/25 75/25 Monomer Feed Rate, gm/hr 100 100 100 70 100 100 100 100 Residual Acrylonitrile 0.82 0.51 0.60 0.17 1.25 1.26 0.51 Residual Styrene 0.41 0.26 0.17 - 0.08 0.09 0.20 Residual TMSN 0.43 0

As can be seen from Examples 107 and 108, polymer/polyols with satisfactory stability were achieved in the low molecular weight polyol with 40/60 and 50/50 acrylonitrile/styrene monomer systems.

EXAMPLES 114-118 These Examples illustrate the preparation of polymer/polyols from Polyol I and high styrene monomer systems using a 50/50 acrylonitrile/styrene polymer as the anchor portion and a polypropylene oxide/butanol adduct of about 2600 mol. wt. condensed with acrylic acid to provide terminal unsaturation as the solvatable portion.

The results are set forth in Table XI: TABLE Xl Example No. 114 115 116 117 118 Preparation Reaction Temp., "C. 120 120 120 120 120 AZO Concentration, wt. 9;; 1.3 1.3 1.3 1.3 1.3 % Monomer 20 20 20 20 20 A/S Ratio 30/70 25/75 10/90 5/95 0/100 Stabilizer Solid, wot. or 1.3 1.8 1.8 1.8 1.8 Monomer Feed Rate 75 75 75 75 75 Residual Acrylonitrile 0.30 0.167 0.07 0.03 Styrene 0.78 1.49 2.96 4.04 6.25 TMSN 0.49 0.47 0.56 0.59 0.69 Toluene 2.71 0.02 - 0 0.97 Benzene 0.04 0.19 0.04 - 0.05 Conversion, Acrylonitrile, % 94.9 96.5 96.4 97.1 Styrene, % 94.3 89.9 83.2 77.3 65.6 Combined, % 94.5 91.3 84 78.3 66.6 Total Polymer in Product, calc. % 18.6 18.0 17 15.6 14 Properties Brookfield Viscosity, cps. 994 1,068 1,200 1,040 690 Filtration Hindrance: 150 Mesh Screen, sec. % thru 100 100 100 100 Solids on Screen, ppm 9.5 820 44 34.8 700 Mesh Screen, sec. > 1200 > 1200 > 1200 > 1200 1200 %thru 55 63 100 54 Solids on Screen, ppm 60 47 1,584 Centrifugible Solids, wt. % 1.2 0.35 8.9 25.1 13.7 These Examples demonstrate that satisfactorily stable polymer/polyols can be made with monomer systems having a relatively high styrene content (see Example 116) with stabilizers having anchor portions of appropriate composition.

EXAMPLES 119-124 These Examples show the preparation of polymer/polyols using Polyols I and III, contrasting the preparation using stabilizers in accordance with the present invention with polymer/polyol preparation without employing a preformed stabilizer.

A continuous polymerization system was used, employing 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 inline mixer to assure complete mixing of the feed components before entering the reactor. The internal temperature of the reactor was controlled to within 1" Centrigrade 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 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 tabulated in Table XII: TABLE XII Example No. 119 120 121 122 123 124 Polyol Polyol I Polyol I Polyol I Polyol III Polyol III Polyol III Preparation Reaction Tempeature, C, 125 130 125 125 130 120 Catalyst AZO TBPO AZO AZO TBPO AZO Catalyst Conc., wt. % in total feed 0.5 1.0 0.5 0.5 1.0 0.44 Stabilier Conc., Wt.% in Polyol feed (1) 6.045 - - 6.045 - Monomer Content in Feed, wt.% 19.97 20.21 12.58 20.32 20.45 7.7 Ratio of Acrylonitrile to Stryrene, wt.% 40/60 40/60 40/60 80/20 80/20 80/20 Combined Conversion, % 88.86 88.87 83.10 85.2 78.7 57.7 Polymer Content, Calc., % 17.7 18.0 10.4 17.3 16.1 4.4 Properties brookfield Viscosity at 25 C., cps 1120 1768 2100 520 610 (layered) Acid No., mg KOH/gm 0.068 0.051 - 0.048 Filtration Hindrance: 150 Mesh Screen, % Through 100.0 100.0 100.0 100.0 100.0 8.7 solids on Screen, ppm 13 12 3 7.0 18.0 2810 700 Mesh Screen, Time, Sec. 220 190 500 129 132 > 1200 %Through 100.0 100.0 0.11 100.0 100.0 1.9 Solids on screen, ppm 17.0 12.0 6190 10 21.0 Centrifugible Solids, wt.% 1.77 9l15 33.35 20.88 41.5 20.0 Calculated Hydroxy No., mg KOH/gm 45.70 45.22 49.72 92.11 92.73 (1) The stabilizer used consisted of an anchor potion formed from a 30/70 acrylonitrile/styrene monomer system and a polypropylene oxide-butanol adduct of about 2600 mol. wt. condensed with methacrylic acid to provide terminal unsaturation as the solvatable portion.

As can be seen from a comparison of Example 119 with Example 121 and Example 122 with Example 124, the use of stabilizers allows the formation of stable polymer/polyols which cannot be prepared by using azo catalysts alone. A comparison of Example 119 with 120 and Example 122 with 123 shows the stabilizers decrease the viscosity and centrifugible solids level in comparison to preparation using only a peroxide catalyst.

EXAMPLES 125-131 These Examples illustrate the preparation of polymer/polyols with a monomer system of acrylonitrile and styrene and/or methyl methacrylate as comonomers using the procedure set forth in Examples 119-124, except that Polyol IV was used.

The experimental conditions and results are tabulated in Table Xlll: TABLE XIII Example No. 125 126 127 128 129 130 131 Preparation Reaction Temperature, C, 120 120 125 120 120 120 120 AZO Conc., wt.% in total feed 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Stabilizer(1) Stabilizer wt. % solids in total feed (1) 2.89 2.77 2.64 2.94 2.94 2.82 2.0 Monomer+AZO Content in Feed, wt.% 19.90 23.40 26.8 29.5 30.4 33.3 20.26 Ratio of methyl Methacrylate/ Acrylonitrile/Styrene, wt.% 25/25/50 25/25/50 25/25/50 25/25/50 25/25/50 25/25/50 60/40/0 Polyol+Stabilizer Feed Rate, gm/hr 2204 2110 2016 1938 1978 1830 2196 Monomer+AZO Feed Rate, gm/hr 548 646 738 812 866 914 558 Product Weight, gm/hr 2736 2748 2746 - 2845 2724 2742 Material Balance,% 99.40 99.70 99.7 - 100.0 99.30 99.56 Residual Acrylonitrile,% 0.77 0.98 0.93 Reactor 0.647 1.05 1.44 Methyl Methozrylate, % 1.07 1.03 1.15 Plugged- 0.869 1.26 2.31 Styene,% 1.48 1.55 1.66 Run Not 1.158 1.68 TMSN, % 0.21 0.29 0.28 completed 0.227 0.28 0.278 Toluene, % 0.13 0.20 0.20 0.374 0.16 0.155 Conversions, Acrylonitrile, % 84.20 82.9 85.9 91.3 87.3 81.9 Methyl Methacrylate,% 78.10 82.0 82.6 88.4 84.5 80.6 Stytrene,% 84.80 86.5 87.4 92.3 89.8 Combined,% 83.00 84.5 85.8 91.1 87.9 87.1 Total PolyA in product by Calc. wt. % 4.2 4.9 5.9 7.00 7.5 6.7 Total Poly MMA in Product by Calc., wt.% 3.9 4.9 5.6 6.8 7.2 9.9 Total Poly S in Product by Calc. wt. % 8.5 10.2 11.9 14.2 15.4 Total Polymer in Product by Calc., wt. % 16.6 20.0 23.4 28.0 30.1 16.1 TABLE XII (Continued) Example No. 125 126 127 128 129 130 131 Properties Viscosity (Brookfield) at 25 C., cps 1268 1364 1484 2000 2280 900 Calculated Hydroxyl No., mg KCH/cm 38.8 37.30 35.7 33.5 32.6 46.16 Filtration Hindrance (2) 150 Mesh Screen, % Thru 8.72 100 100 100 66.8 100 solids on Screen, ppm 3990 6 16 4.9 198 11 700 Mesh Screen, time. sec. 500 1200 450 1200 600 170 % Thru 0.9787 33.19 15.8 13 2.55 100 Solids on Screen, ppm 38630 31.40 111 142 6250 7 Centrifugible Solids, wt.% 1.77 1.85 2.27 2.52 2.99 1.

Remarks Noticed Suspecting Reaction Reaction was increase in use of 80/20 was started using viscosity of acryloni- started at a 25/25/50 the product trile/styrene low monomer MMA/A/S mix during line- mix for start conc. and instead of out period. up. then in- 80/20/A/S mix. creased gradually.

1) The stabilizer were as fillows: Examples 125-130: A 30/70 acrylonitrile/stryrene monomer ratio used to form the anchor portion and a polypropylene oxide-butanol adduct of about 2600 mol. wt. condensed with acrylic acid to provide terminal unsaturation as the solvatable constituent.

Example 131: Same as in Examples 125-130, except that a 50/50 acrylonitrile/styrene monomer ratio was used to form the anchor portion.

2) In Example 130, Cellosolve solvent (ethylene glycol monoethyl ether) was used rather than isopropanol.

As can be seen from Examples 126 and 131, stable polymer/polyols can be formed when methyl methacrylate is substituted for part or all of the styrene in the monomer system.

EXAMPLES 132-147 These Examples show preparation of further polymer/polyols using the process set forth in connection with Examples 119-124.

The experimental conditions and results are set forth in Table XIV: TABLE XIV Example No. 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 Preparation Polyol Polyol # Polyol IV # Polyol V # Reaction Temperature, C.(1) 125 125 125 125 125 120 120 125 125 125 125 125 125 125 125 125 Stabilizer(2) Cone., wt. 25.% in total feed 1.2 1 2 2.8 2.54 2.69 2.82 2 2 2 1.82 1.77 4.66 4.47 4.3 4.08 AZO, conc., wt% in total feed 1.0 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.58 1.3 1.3 1.3 1.3 Monomer Content in Feed, wt.% 20.54 20.39 20.12 23.18 30.49 26.35 33.43 20.36 20.07 23.74 27.46 20.70 23.99 27.9 30.7 Ratio of Acrylonitrile to Styrene, wt% 40/60 40/60 40/60 40/60 40/60 40/60 30/70 25/75 20/80 30/70 30/70 30/70 30/70 30/70 30/70 Polyol Feed Rate, m/hr 2190 2194 2160 2108 1960 2012 1844 2204 2206 2206 2004 2002 2221 2144 2018 1948 Monomer Feed rate, gm/hr 566 562 544 636 860 720 926 562 564 554 624 758 580 677 780 862 Product Weight, gm/hr 2742 2746 2690 2732 2814 2724 2753 2756 2756 2749 2612 2752 2784 2806 2786 2786 Material Balance, % 99.49 9o.64 99.48 99.56 99.79 99.71 99.38 99.64 99.49 99.42 99.39 99.71 99.39 99.47 99.57 99.14 Residual Acrylonitrile, % 0.85 1.08 1.20 1.16 1.02 0.99 0.93 0.846 0.834 0.773 0.95 0.94 0.78 0.75 0.7 0.85 Styrene, % 0.95 1.21 1.28 1.25 0.91 0.95 1.25 2.05 2.69 3.77 2.25 2.22 1.55 1.64 1.66 1.57 TMSN, % 0.24 0.27 0.26 0.20 0.20 0.26 0.219 0.221 .210 0.194 0.234 0.277 0.6 0.55 0.57 0.57 Conversion, Acrylonitrile, % 89.2 86.5 84.8 87.3 91.5 90.5 93.0 85.8 83.3 80.4 86.5 88.5 86.7 89.0 90.5 90.4 Styrene, % 91.9 89.9 89.2 90.9 94.9 93.9 93.7 85.3 82.0 76.1 86.2 88.2 89.7 89.7 91.1 92.4 Combined, % 90.8 88.5 87.4 89.4 93.6 92.5 93.4 85.4 82.3 76.9 86.3 88.3 89.5 89.5 90.9 91.8 Total Poly A in Product by Calc., wt.% 7.1 7.0 6.8 8.1 11.20 9.5 12.5 5.3 4.3 3.3 6.20 7.4 5.2 6.2 7.4 8.2 Toital Poly S in Product by Calc., wt.% 11.0 11.0 10.8 12.7 17.40 14.9 18.9 12.2 12.7 12.5 14.5 17.1 12.4 146.6 17.4 19.5 Total Polymer in Product by Calc. wt.% 18.1 18.k0 17.6 20.8 28.6 24.4 31.4 17.5 17.0 15.8 20.7 24.5 17.5 20.8 24.8 27.7 Properties Brookfield Viscosity at 25 C., cps 936 928 1220 1440 2948 2744 3210 1280 1636 2640 1420 2104 1012 1160 1180 1720 Acid No., mg/KOH/gm - - - - - - - - - - - - - - - Calc. Hydroxyl No., mg KOH/gm 45.4 45.4 38.4 36.8 33.3 35.2 31.94 38.47 38.70 39.2 36.93 35.2 46.5 42.4 42.4 40.8 Filtration HIndrance (3): 105 Mesh Screen, % thru 100 100 100 100 2.76 7.02 100 100 100 100 100 100 100 100 100 100 Solids on Screen, ppm 10 9 3.4 13 14838 3951 6 21.13 21 33.4 53 48 8 6 6 13 700 Mesh Screen, time, sec. 140 138 206 330 300 1200 600 600 1200 500 436 500 188 210 218 600 % thru 100 100 100 100 0.14 0.07 1.67 17.87* 64.04* 19.79 24 0.85 100 100 100 70 Solids on Screen, ppm 5 214 12.3 17 129696 84848 691 116 21 409 842 20900 32 12 7 4 Centrifugible Solids, wt.% 1.75 1.93 1.59 1.48 12.4 12.69 5.53 2.22 7.80 31.19 2.72 14.92 1.9 2.6 3.2 4.3 0 0 0 0 0 0 *Suspecting seeds from line-out period.

(1) Temperatures held within about #1.5 C.

(2) the stabilizers used were as follows: Examples 132-138: As identified in Examples 125-130.

Examples 139-143: As identified in Example 131.

Examples 144-147: Anchor portion was made from a 50/50 acrylonitrile/styrene monomer system and a polypropylene oxide-butanol adduct of about 2600 mol. wt. condnsed with methacrylic acid to provide terminal unsaturation as the solvatable portion.

*(3) Cellosolve (Registered Trade Mark) solvent was used in place of ispropanol in Examples 142-143.

While relatively stable polymer/polyols can be made from monomer systems with relatively high styrene contents, Examples 144-147 demonstrate that, ignoring any possible effect created by the change in polyol, stability is improved by significantly increasing the stabilizer concentration, allowing preparation of stable polymer/polyols with 70% styrene in the monomer system at polymer contents up to 27.7%.

EXAMPLES 148-1 55 These Examples demonstrate the preparation of polymer/polyols having relatively high polymer contents (viz.-24 to 36%) at acrylonitrile/styrene ratios of 30/70.

The experimental conditions and results are tabulated in Table XV: TABLE XV Example No. 148 149 150 151 152 153 154 155 Preparation Reaction Temperature C. 120 120 120 120 120 120 120 120 Polyol I I I IV IV V V V AZO Concentration, wt.% 1.5 1.8 2.1 1.5 2.1 1.8 2.1 2.1 %Monomer 24 28 33.3 24 33.3 28 33.3 36 A/S Ratio 30/70 30/70 30/70 30/70 30/70 30/70 30/70 30/70 Stabilizer (1) Solid Stabilizer, wt.% 2.0 2.52 3 3 3 2.5 3 3 Monomer Feed Rate, gm/hr 60 60 60 60 60 60 60 60 ResidualAcrylonitrile 0.27 0.12 0.19 0.28 0.25 0.28 0.23 0.33 Styrene 0.50 0.73 0.88 0.98 0.67 0.94 1.01 1.19 TMSN 0.70 0.78 0.92 0.76 0.83 0.71 1.00 0.89 Toluene - - - - - - - - Benzene 0.06 0.07 0.10 0.08 0.08 0.08 0.01 0.09 Conversion, Acrylonitrile, % 96.2 98.5 98.0 96.0 97.4 96.6 97.6 96.8 Styrene.% 97.0 96.1 96.1 94.3 97.0 95.1 95.5 95.1 Combined, % 96.7 96.9 96.7 94.8 97.2 95.5 96.1 95.6 Total Polymer in Product, wt. % 22.7 26.4 31.2 22.2 31.3 26.0 31 33 Properties BrookfieldViscosity, cps. 1,616 1,616 2,800 3,128 7,440 1,988 2,640 3,500 Filtration Hindrance, 150 Mesh Screen, sec % thru 28 100 - 4.2 11.7 29 - 700 Mesh Screen, sec. > 1200 > 1200 - - > 1200 > 1200 - thru 4.3 7.7 - - 0.7 1.7 - Solids on Screen, ppm 323 365 - - 5475 - - Centrifugible Solids, wt, % 2.73 1.29 1.82 2.86 8.12 1.67 2.37 3.29 (1) Described in Example 131.

While the filtration hindrance characteristics are substantially less than optimum, polymer/polyols with satisfactory viscosity and centrifugible solids characteristics were formed in all the Examples.

EXAMPLES 156-159 These Examples further illustrate the preparation of polymer/polyols using a monomer system in which methyl methacrylate is employed with various styrene and acrylonitrile monomer systems and also acrylonitrile and styrene alone.

The experimental conditions and the properties are set forth in Table XVI, the base polyol used being Polyol 1: TABLE XVI Example No. 156 157 158 159 Preparation Reaction Temperature, C. 120 120 120 120 AZO Concentration, % by wt. 1.3 1.0 1.0 Stabilizer, from Example 21 21 125-130 131 Concentration of Stabilizer (wt. %) 1.3 1.3 1.3 2 Monomer(s), wt. % 20 20 20 20 Acrylonitrile/Methyl Methacrylate/ Styrene, ratio 25/25/50 15/25/60 0/40/60 40/60/0 Residual Acrylonitrile, % 0.27 0.21 0.07 0.39 Styrene, % 0.48 0.65 1.74 0.61 TMSN, % 0.49 0.46 0.45 0.45 Toluene, % % - 2.47 0.13 Benzene, % 0.38 0.22 0.88 - Conversions, Acrylonitrile, % 94.6 95.7 - 95.1 Methyl Methacrylate, % - - 94.8 Styrene, /0 95.7 94 79.3 94.9 Combined, % 95 94.5 80 Total Polymer in Product, wt. % 19 18.9 16 18.8 Properties Viscosity (Brookfield), cps at 250C. 1,240 1,000 1,286 1,144 Filtration Hindrance: 150 Mesh Screen, sec. 7 11 1200 % Thur 100 100 1.8 100 Solids on Screen, ppm 48 25 29,890 53 700 Mesh Screen, sec. 360 360 - 307 %Thru 100 100 - 100 Solids on Screen 89 50 - 140 Centrifugible Solids, wt. % 1.8 1.9 11.8 0.96 With the stabilizers used, as can be seen by comparing Example 158 with the other Examples, a less stable polymer/polyol is formed when no acrylonitrile is used in the monomer system.

EXAMPLES 160164 These Examples show the preparation of polymer/polyols in Polyol I with a monomer system containing relatively high styrene content.

The experimental conditions and resulting properties are set forth in Table XVII: TABLE XVII Example No. 160 161 162 163(1) 164(1) Preparation Reaction Temperature, "C. 120 120 120 120 120 AZO, wt. % 1.3 1.3 1.3 1.3 1.3 Stabilizer, wt. A0 (2) 1.3 1.8 1.8 1.8 1.8 Monomer, wt. % 20 20 20 20 20 Monomer A/S ratio 40/60 25/75 20/80 10/90 5/95 Monomer Catalyst Feed Rate, gm/hr 75 75 75 75 75 Residual Acrylonitrile, % 0.44 0.14 0.14 0.07 0.03 Styrene, % 0.30 1.42 2.39 2.96 4.04 TMSN, % 0.56 0.47 0.52 0.56 0.59 Toluene, % 2.58 0.45 0 0 0 Conversion, Acrylonitrile, % 94.4 97.2 96.4 96.4 97.1 Styrene, % 97.5 90.4 87.0 83.2 77.3 Combined, % 96.3 92.1 89.44 84.0 78.3 PolyA in Product by Calc., wt. % 7.5 4.8 3.8 1.8 1.0 PolyS in Product by Calc., wt.% 11.5 13.2 13.3 14.7 14.6 Total Polymer in Product by Calc., wt.% 19 18 17.1 16.5 15.6 Properties Viscosity (Brookfield) at 25 C., cps 1,160 944 1,076 1,20 1,040 Filtration Hindrance: 150 Mesh Screen, % thru 100 - - 100 100 Solids on Screen, ppm 31 - - 44.4 34.8 700 Mesh Screen, time, sec. > 1200 - - > 1200 > 1200 %thru 40 - - 99 54 Solids on Screen, ppm 110.8 48.6 1,584 Centrifugible Solids wt. % 0.7 0.25 0.38 8.9 25.1 (1) Examples 117 and 118, respectively. Reproduced herein for purposes of comparison.

(2) Stabilizer described in Examples 114118.

This further illustrates the formation of stable polymer/polyols using high styrene in the monomer system.

EXAMPLES 165-171 These Examples illustrate the preparation of polymer/polyols in Polyol V, employing the procedure described in connection with Examples 119-124, and compare the efficacy of stabilizers made from a solvatable portion having terminal unsaturation (Examples 168-171) and those made without terminal unsaturation (Examples (165-167)).

The experimental conditions and results are tabulated in Table XVIII: TABLE XVIII Example No. 165 166 167 168(1) 169(1) 170(1) 171(1) Preparation Reaction Temperature, "C. (2) 125 125 125 125 125 125 125 AZO Conc., wt. % in total feed 1.3 1.3 1.3 1.3 1.3 1.3 1.3 Stabilizer Conc., wt. % in total feed (3) 4.34 4.16 3.97 4.66 4.47 4.3 4.08 Monomer + AZO Content in Feed, wt. % 20.70 24.04 27.55 20.70 23.99 27.88 30.68 Ratio of Acrylonitrile to Styrene, wt. % 30/70 30/70 30/70 30/70 30/70 30/70 30/70 Polyol + Stabilizer Feed Rate, gm/hr 2206 2123 2020 2221 2144 2018 1948 Monomer + AZO Feed Rate, gm/hr 576 672 768 580 677 780 862 Product Weight, gm/hr 2759 2779 2770 2784 2806 2786 2786 Material Balance,% 99.17 99A3 99.35 99.39 99.47 99.57 99.14 Residual Acrylonitrile, % 0.66 0.69 0.70 0.78 0.75 0.76 0.85 Styrene,% 1.51 1.63 1,70 1.55 1.64 1.66 1.57 TMSN,% 0.54 0.70 0.60 0.61 0.55 0.57 0.55 Tuluene,% - - - 0.83 0.84 0.71 0.79 m-xylene, /o ile 0/ 0.43 0.43 0.43 - - - - Conversion, Acrylonitrile, % 88.8 90.0 91.2 86.7 89.0 90.5 90.4 Stryene, % 89.0 89.8 90.8 88.7 89.7 91.1 92.4 Combined, % 88.9 89.9 90.9 88.1 89.5 90.9 91.8 Total Poly A in Product by Calc., wt. % 5.30 6.29 7.37 5.19 6.22 7.41 8.18 TotalPolySin ProductbyCalc.,wt% 12,39 14.67 17.14 12.38 14.63 17.40 19.51 Total Polymer in Product by Calc., wt. % 17.69 20.96 24.51 17.56 20.85 24.81 27.69 Properties Brookfield Viscosity at 25 C., cps 960 1096 1176 1012 1160 1180 1720 Acid No., mg KOH/gm - - 0.028 - - - Calculated Hydroxyl No., mg KOH/gm 46.42 44.58 42.57 46.49 44.64 42.41 40.78 Filtration Hindrance: 150 Mesh Screen, /0 thru 100 100 4.5 100 100 100 100 Solids on Screen, ppm 1 13 1544 8 9 6 13 700 Mesh Screen, time, sec. 320 300 300 188 210 218 600 % thru 100 8 0.5 100 100 100 70 Solids on Screen, ppm 9 500 9300 32 12 7 4 CentrifugibleSolids,wt. 70 3.94 6.33 11.04 1.90 2.65 3.66 4.33 (1) Examples 144 147, respectively. Reproduced herein for purposes of comparison.

(2) Temperatures held within about #1.5 C.

(3) The stabilizer used for Examples 165167 is described in Example 34.

As can be seen, both types of stabilizers are effective although, at the concentrations utilized, a comparison of Example 170 with Example 167 shows that the stabilizers having unsaturation in the solvatable portion provide improved results when the polymer content is higher at similar stabilizer levels.

EXAMPLES 172-187 These Examples show the use of polymer/polyols to prepare flexible foams.

Examples 172-173 and 176-177, wherein the polymer/polyols were prepared using stabilizers in accordance with the present invention, can be contrasted with the remaining Examples wherein the polymer/polyols were prepared either with a peroxide or an azo catalyst and no stabilizer. The experimental conditions are tabulated in Table XIX: TABLE XIX

Example No. 172 173 174 175 176 177 178 179 180 Polymer/Polyol Polyol Polyol V # Polyol I Polyol V Hydroxyl No., mg KOH/g 45.47 45.56 44.56 44.63 42.41 40.78 45.12 42.7 37.5 A/S Ratio 30/70 30/70 30/70 30/70 30/70 30/70 40/60 50/50 78/22 Solids Content, wt.% 19.35 19.20 20.98 20.86 24.81 27.69 18.04 18 32.94 Catalyst AZO+ AZO+ TBKPO TBPO AZO+ AZO+ TBPO AZO TBPO Stabi- Stabi- Stabi- Stabilizer(1) lizer lizer lizer Amount of Stabilizer 4.2 4.5 0 0 4.3 4.1 0 0 0 Foam Formulation # Polymr/Polyol 100 100 100 100 100 100 100 100 100 60 Polyol V - - - - - - - - - 40 Water 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 Catalyst 0.10 0.10 013 0.13 0.10 0.10 0.10 0.10 0.10 0.10 Stannous Octoate 0.175 0.25 0.25 .25 0.25 0.25 0.175 0.25 0.25 0.25 Silicone Surfactant 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Isocyanate TDI 107 Index 48.8 48.8 48.8 48.8 48.2 43.7(2) 48.8 48.8 47.5 49.5 Rise Time, secs, 147 139 Creams and gels Gels 130 164 110 114 105 very fast. slowly, split Comments OK OK Top splits and Small split. OK OK OK powdery foam. collapsed.

(1) The stabilizers used were as follows: Example 172: described in Example 34, Examples 173, 176 and 177: described in Example 131.

(2) Index of 98.

As can be seen by comparing Examples 172 and 173 with Examples 174 and 175 (where no stabilizer was used), satisfactory foams were prepared with the 30/70 acrylonitrile/styrene polymer/polyols made with the stabilizer while top splits and powdery foams resulted from use of the polymer/polyols prepared with a peroxide catalyst and no stabilizer.

The physical properties of the foams which were tested are tabulated in Table XX: TABLE XX Example No. 181 182 183 184 185 186 187 Foam Preparation, Example 172 173 177 178 179 180 180 Density, pof 1.58 1.53 1.54 1.53 1.52 1.54 1.50(1) Air Porosity, ft3/min/ft2 84.5 82.3 66.5 76.4 80.6 50.0 86.0 Resiliency, jO ball rebound 32 32 27 32 36 23 32 ILD (Ibs/SO in2) (2) 25% 59.1 56.1 59.9 52.7 65.0 91.3 55.2 65% 113.3 106.0 115.3 104.3 117.3 170.0 99.0 25% Return, % 57.2 56.0 51.4 55.6 56.1 46.2 54.9 Load Ratio 1.92 1.89 1.92 1.98 1.80 1.86 1.79 Tensile Strength, psi 16.3 17.9 16.5 17.9 17.6 23.1 18.4 Elongation, % 83 108 78 112 98 87 120 Tear Resistance, pli 1.29 1.73 1.32 2.04 1.70 2.05 2.39 90% Compression Set, Cd, % 10.7 12.6 17.3 15.9 7.7 59.0 8.1 (1) Formulation based on 60 parts of the Polymer/Polyol prepared in Example 179 and 40 parts of Polyol V for total polymer solids contents of 19.76 per cent.

(2) Specimen dimensions of 12x12x4 inches.

The ILD values in all instances were satisfactory.

EXAMPLES 188-191 These Examples illustrate the improvement in discoloration resistance with foams prepared from polymer/polyols in which the acrylonitrile/styrene ratio has been reduced from 50/50 to 40/60 and 30/70.

The foams evaluated were made using the polymer/polyols described in Table XXI: TABLE XXI Polymer/ Polymer/ Polymer/ Polymer/ Formulation Polyol A Polyol B Polyol C Polyol D Polyol IV IV IV IV A/S Ratio 50/50 40i60 30/70 30/70 Total Polymer Content 18 18 17.13 18.01 Viscosity, cps, at 250C. 1500 3000 1464 6420 Catalyst AZO TBPO AZO TBPO Stabilizer (I) No No Yes No (1) The stabilizer used is described in Example 131.

Foams were prepared using polymer/polyols A-D, and the foam formulations and the resulting discoloration characteristics are set forth- in Table XXII: TABLE XXII Example No. ~ 188 189 190 191 Polymer/Polyol A B C D phr 100.0 100.0 100.0 100.0 Water 6.0 6.0 6.0 6.0 Urethane Catalyst 0.07 0.07 0.07 0.07 Silicone Surfactant II 1.2 1.2 1.2 1.2 Stannous Octoate 0.20 0.20 0.20 0.20 TDI Index 105 105 105 105 Height of Rise, inches 26.0 25.3 24.0 24.0 Nopco* Breathability, SCFM 3.25 1.30 1.95 2.25 Density, pcf 1.02 1.04 1.11 1.09 Reflectometer Readings: Top 59.3 71.5 78.3 74.6 Middle 56.8 71.5 77.4 72.7 Bottom 61.8 74.6 78.9 76.2 Bottom-Center 5.0 3.1 1.5 3.5 *Registered Trade Mark As can be seen, the data shows a general trend of decreased scorch with decreased acrylonitrile content in the monomer system used to form the polymer/polyols.

EXAMPLES 192-195 These Examples illustrate the use of various anchor portion compositions in preparing polymer/polyols using the procedure described in Examples 119-124 and with a 40/60 acrylonitrile/styrene monomer system. The solvatable portion in Examples 193-195 consisted of polypropylene oxide material III condensed to form an acrylate. Polypropylene oxide material III was used in Example 192 without modification.

The experimental conditions and results are tabulated in Table XXIII: TABLE XXIII Example No. 192 193 194 195 Polyol IV IV IV I Preparation Reaction Temperature, OC. 125 125 125 125 AZO conc., wt. % in total feed 0.5 0.5 0.5 0.5 Stabilizer Anchor Portion, ratio of Acrylonitrile/Styrene 45/55 45/55 50/50 30/70 Stabilizer, wt. % in total feed 2.48 2.0 2.0 2.0 Monomer and AZO content in feed, wt. % 20.54 20.65 20.59 19.97 Ratio of Acrylonitrile/Styrene, wt. % 40/60 40/60 40/60 40/60 Residual Acrylonitrile, % 1.03 1.13 1.19 1.08 Styrene, % 1.05 1.63 1.67 1.48 TMSN, % 0.29 0.231 0.25 0 While the viscosity and centrifugible solids level of all of the polymer/polyols were satisfactory, only the Example 195 polymer/polyol exhibited the preferred filtration hindrance characteristics.

EXAMPLES 196-199 These Examples show the effect of increasing the amount of monomer used in - preparing a 40/60 acrylonitrile/styrene polymer/polyol.

The experimental conditions and results are tabulated in Table XXIV, the base polyol used being Polyol V: TABLE XXIV Example No. 196 197 198 199 Preparation Reaction Temperature, "C. 125 125 125 125 AZO conc., wt. % in total feed 1.3 1.3 1.3 1.3 Stabilizer Anchor Portion, ratio of Acrylonitrile/Styrene (1) 30/70 30/70 30/70 30/70 Stabilizer, wt. % in total feed 5.65 5.11 4.74 4.37 Monomer and AZO content in feed, wt. % 32.17 38.60 43.13 47.56 Ratio of Acrylonitrile to Styrene, wt. % 40/60 40/60 40/60 40/60 Residual Acrylonitrile, % 1.07 0.75 1.12 1.03 Styrene, % 1.25 0.84 1.09 0.95 TMSN, % 0.65 0.47 0.65 0.63 Toluene, % Conversion, Acrylonitrile, % 91.46 95.0 93.42 94.45 Styrene, % 93.34 96.27 95.73 96.59 Combined, % 92.59 95.77 94.80 95.74 Total Polyacrylonitrile in Product, by calc. wt. % 11.59 14.42 16.0 17.85 Total Polystyrene in Product, by calc. wt. % 17.75 21.92 24.59 27.38 Total Polymer in Product, by calc. wt. % 29.34 36.34 40.59 45.23 Product Properties Viscosity (Brookfield) at 250C., cps 3310 8800 11960 35500 Calculated Hydroxyl No., mg KOH/gm 39.85 35.90 33.50 30.89 Filtration Hindrance: 150 Mesh Screen, % thru 100 100 100 5.84 Solids on Screen, ppm 12 22 13 2374 700 Mesh Screen, time, sec. 212 210 218 300 %thru 100 100 100 0.335 Solids on Screen, ppm 13 15 14 31493 Centrifugible Solids, wt. % 2.51 5.16 5.56 21.21 (1) Solvatable portion comprises a polypropylene oxide-butanol adduct of about 2600 mol. wt. condensed with acrylic acid to provide terminal unsaturation.

As can be seen from Example 196--198, while the viscosity increased with increasing monomer content, acceptable filtration hindrance was provided, up to a polymer content of about 40 percent.

EXAMPLES 200-211 These Examples illustrate the preparation of polymer/polyols from a monomer system with high styrene content and with various stabilizers and with varying monomer system contents.

Experimental conditions and results are tabulated in Table XXV, the base polyol used being Polyol V: TABLE XXV Example No. 200 201 202 203 204 205 206 207 208 209 210 211 Preparation Reaction Temperature, C. 125 125 125 125 125 125 125 125 125 125 125 125 AZO conc., wt.% in total feed 1.3 1.3 1.30 1.49 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 Stabilizer Anchor Portion, ration of Acrylonitrile/Styrene 55/45 55/45 30/70 30/70 50/50 50/50 50/50 50/50 50/50 50/50 50/50 50/50 Stabilizer, wt.% in total feed 91) 4.64 4.45 4.63 4.45 4.64 4.45 4.23 4.05 4.69 4.04 4.23 4.07 Monomer and AZO content in feed, wt.% 21.01 24.37 21.22 24.39 21.0 24.37 28.03 31.14 20.14 24.52 28.05 30.76 Ratio of Acrylonitrile/Styrene, wt.% 30/70 30/70 30/70 30/70 30/70 30/70 30/70 30/70 30/70 30/70 30/70 30/70 Residual Acrylonitrile,% 0.62 0.61 0.75 0.71 0.76 0.81 0.78 0.78 0.74 0.76 0.75 0.79 Styrene,% 1.07 1.37 1.95 1.87 1.92 2.08 2.26 2.06 1.93 2.02 1.87 2.04 TMSN,% 0.43 0.47 0.60 0.69 0.62 0.61 0.61 0.65 0.54 0.61 0.59 0.65 Xylene,% 0.68 0.30 - - - - - - - - - conversions, Acrylonitrile,% 89.61 91.21 87.33 89.68 87.23 88.31 90.40 91.32 87.02 89.16 90.96 91.10 Styrene,% 92.32 91.53 85.88 88.35 86.17 87.14 88.06 90.17 85.50 87.65 90.05 90.15 Combined,% 91.51 91.44 86.32 88.75 86.47 87.49 88.76 90.52 85.95 88.10 90.24 90.43 total Polyacrylonitrile in Product, by calc. wt.% 5.40 6.44 5.37 6.33 5.31 6.30 7.49 8.43 5.08 6.39 7.49 8.30 Total Polystrene in Product, by calc. wt.% 12.98 15.10 12.33 14.56 12.24 14.51 17.01 19.41 11.64 14.66 187.35 19.17 Total Polymer in Prouct, by calc. wt.% 18.38 21.54 17.70 20.89 17.55 20.81 24.50 27.84 16.72 21.05 24.84 27.47 Product Properites Viscosity (Brookfield) at 25 C., cps 1700 2264 1122 1290 994 1130 1260 1828 970 1166 1298 1504 Calculated Hydroxyl No., mg KOH/gm 46.03 44.25 46.41 44.62 46.5 44.66 42.58 40.70 46.97 44.53 42.39 40.91 Filtration Hindrance 150 Mesh Screen,% thru 100 7 100 100 100 100 100 266 100 100 100 100 Solids on Screen, ppm 17 2186 13 9 52 15 31 4605 10 16 17 27 700 Mesh Screen, time, sec. 300 15 196 176 208 290 1200 - 211 275 245 1200 % thru 1.16 0.15 100 100 100 100 46.67 - 100 100 100 42.34 solids on Screen, ppm 2112 97333 13 5 3 10 32 - 13 13 13 37 Centrifugible Solids, stripped wt.% 17.43 49.72 1.45 1.77 3.57 5.18 6.28 21.35 1.77 2.11 2.46 3.73 (1) Solvatable portions comprised: Examples 200-201: Polypropylene oxide material III Examples 202-203: Polypropylene oxide material III condensed with acrylic acid to provide terminal monethylenic unsaturation Examples 204-207: Polypropylene oxide material IV Examples 208-211: Polypropylene oxide material IV condensed with acrylic acid to provide terminal monoethylenic unsaturation Stabilizers are effective, as can be seen, for example, from Examples 204 and 211, regardless of whether or not the solvatable portion was made from a macromonomer condensed with acrylic acid. Somewhat more stable polymer/polyols at higher polymer contents can, however, be achieved at approximately equivalent stabilizer contents with the acrylate mode as can be seen by comparing Examples 206 and 207 with Examples 210 and 211.

EXAMPLES 212-217 These Examples illustrate the preparation of polymer/polyols with stabilizers prepared with 30/70 and 50/50 acrylonitrile/styrene anchor portions and with varying solvatable portions.

The polypropylene oxide material used for Examples 212-215 was material III and was a monohydroxyl propylene oxide produced from propylene oxide and butanol; the average molecular weight for the polypropylene oxide material of Examples 216 and 217 was about 2555. In Examples 212-213, the macromonomer was prepared by condensing 1 mole of maleic anhydride per 1 mole of the polypropylene oxide material; in Examples 214-215, 1 mole of TDI was reactd with 1 mole of the polypropylene oxide material, followed by reaction of 1 mole of hydroxyethylacrylate per mole of the TDI - polypropylene oxide material reaction product; and, in Examples 216-217, 1 mole of TDI per 2 moles of the polypropylene oxide material were reacted to form the solvatable portion.

Experimental conditions and results are set forth in Table XXVI, the base polyol used being Polyol V: TABLE XXVI Example No. 212 213 214 215 216 217 Preparation Reaction Temperature, C. 120 120 120 120 120 120 AZO conc.,wt.% 1.0 1.0 1.0 1.0 1.0 1.0 Stabilizer Anchor Portion, Acrylonitrile/Styrene ratio 30/70 50/50 30/70 50/50 30/70 50/50 Stabilizer, wt.% 1.3 1.8 1.3 1.8 1.3 1.8 Linkage Species (a) (1) (1) (2) (2) (3) (3) Ratio of Acryloitrile/Styrene in Monomer System 40/60 30/70 40/60 30/70 40/6 30/70 Monomers, wt. % 20 20 20 20 20 20 Residual Acrylonitrile, % 0.22 0.08 0.27 0.10 0.40 0.02 Styrene, % 0.34 0.77 0.41 0.82 0.42 0.4 TMSN,% 0.46 .50 0.51 0.38 0.45 0.40 Toluene,% 3.22 .05 2.16 0.4 2.49 0.88 Benzene,% - Convesion, Acrylonitrile,% 96.1 98.6 95.3 98.3 93.0 99.7 Styrene,% 97.4 94.4 97.0 94.0 96.9 97.1 Combined,% 97.0 95.6 96.5 95.3 95.7 97.8 Total Polymer in Product 19.2 18.6 19.0 18.6 19.0 19.0 Product Properties Viscosity (Brookfield) 1,100 1,068 1,360 1.186 1,196 1,044 Filtration Hindrance: 150 Mesh Screen, % thru 100 100 100 100 30.2 100 Solids on Screen, ppm 24 46 92 48 151 12 700 Mesh Screen, time, sec. > 1200 > 1200 > 1200 520 > 1200 > 1200 %thru 30.8 34.8 12.7 100 3.3 57 Solids on Screen, ppm 102 445 260 27 1425 17 Centrifugible Solids, wt. % 0.98 0.78 0.96 0.97 0.12 1.13 (a) (1) denotes maleic anhydride (2) denotes toluene diisocyanate with hydroxyethylacrylate (3) denotes toluene diisocyanate As shown, the stabilizers using the various techniques to form the macromonomer provide satisfactory stabilization. The technique of Examples 216-217 provides a further processing advantage in that stabilizers of the free radical mode can be formed at relatively lower temperatures, e.g., 1000C.

EXAMPLES 218-224 These Examples show the use of stabilizers wherein terminal ethylenic unsaturation in the macromonomer was accomplished by conventional ester interchange or transesterification and illustrate the effectiveness of these stabilizers in relation to stabilizers produced using acrylic acid condensed with polypropylene oxide material III and also as compared to stabilizers formed by the free radical grafting mode.

Experimental conditions and results are displayed in Table XXVII, the base polyol used in Examples 218, 219, 220 and 222 being Polyol V, whilst that used in Examples 221, 223 and 224 being Polyol 1: TABLE XXVII Example No. 218 219 220 221 222 223 224 Preparation Reaction Temperature, C. 120 120 120 120 120 120 120 AZO conc., wt.% 1.0 1.0 1.0 1.0 1.3 1.3 1.3 Stabilizer Anchor Portion, Acrylonitrile/Styrene ratio 30/70 30/70 50/50 40/60 45/55 50/50 30/70 Stabilizer, wt. % 1.3 1.3 1.3 1.3 4.3 1.3 1.3 Linkage Species (a) (1) (1) (1) (2) (2) (3) (3) Ratio of Acrylonitrile/Styrene in Monomer System 40/60 40/60 30/70 40/60 30/70 30/70 40/60 Monomers, wt % 20 20 20 20 20 20 20 Rsidual Acrylonitril, % 0.36 0.33 0.08 0.28 0.66 0.3 0.35 Styrene, % 0.36 0.37 0.69 0.70 1.51 0.78 0.22 TMSN, % 0.45 0.51 0.4 0.62 0.54 0.49 0.46 Toluene, % 2.5 2.34 - - - 2.71 2.58 Benzene, % Conversion, Acrylonitrile, % 95.2 95.6 99.0 96.4 88.8 94.9 95.9 Styrene, % 96.8 96.3 93.8 94.0 89.0 94.3 98.1 Combined, % 96.3 96.2 95.9 94.8 88.9 94.5 97.1 Total Polymer in Product 19.0 19.0 18.9 18.7 17.69 18.6 19 Product Properties Viscosity (Brookfield) 4,000 3,230 27,800 1,030 960 994 1,116 filtration Hindrance 150 Mesh Screen, % thru 100 100 5.8 71.2 100 100 100 Solids on Screen, ppm 77 79 1.953 62 1 9.5 33 700 Mesh Screen, time, sec. > 1200 > 1200 - > 1200 320 > 1200 610 % thru 37.3 5.7 - 4.5 100 55 100 solids on Screen, ppm 194 179 - 1,311 9 47 54 Centrifugible Solids, wt. % 1.6 1.9 5.9 1.6 3.9 1.3 0.56 (a) (1) denotes transesterification using ethyl acrylate (2) denotes free radical mode (3) denotes condensation with acrylic acid Example 218 demonstrates that utilizing transesterification provides a further useful alternative technique for preparing satisfactory stabilizers.

EXAMPLES 225-232 These Examples show the effect on stability of polymer/polyols prepared from a 40/60 acrylonitrile/styrene monomer system caused by varying the composition of the anchor portion of the stabilizer. The solvatable portion was formed by condensing polypropylene oxide material III with acrylic acid.

The experimental conditions and results are tabulated in Table XXVIII, the base polyol used being Polyol 1: TABLE XXVIII Example No. 225 226 227 228 229 230 231 232 Preparation Reaction Temperature, C. 120 120 120 120 120 120 120 120 AZO conc., wt. % 1 1 1.3 0.78 1.3 0.78 0.78 1 Stabilizer Anchor Portion, Acrylonitrile/Styrene ratio 10/90 20.80 30/70 40/60 50/50 60/40 70/30 80/20 Stabilizer, wt. % 1.3 1.3 1.4 1.3 1.3 1.3 1.3 1.3 Ratio of Acrylonitrile/Styrene in Monomer System 40/60 40/60 40/60 40/60 40/60 40/60 40/60 40/60 Monomers, wt. % 20 20 20 20 20 20 20 20 Residual Acrylonitrile, % 0.51 0.46 0.35 0.45 0.44 0.45 0.43 0.56 Styrene, % 0.14 0.16 0.22 0.17 0.30 0.16 0.21 0.18 TMSN, % 0.39 0.48 0.46 0.45 0.56 0.47 0.35 0.50 Toluene, % 3.39 3.57 2.58 3.66 2.58 2.95 3.00 3.12 Conversion, Acrylonitrile, % 93.3 94.0 95.9 94.0 94.4 94.0 94.3 92.6 Styrene, % 98.8 98.6 98.1 98.6 97.5 98.6 98.2 98.4 Combined, % 96.5 96.8 97.1 96.8 96.3 96.8 96.7 96.1 Total Polymer in Product, % 19.2 19.1 19.0 19.1 19 19.1 19.0 19.0 Product Properties Viscosity (Brookfield), 25 C., cps 7,860 1,528 1,166 1,680 1,160 1,150 1,124 1,528 Filitrtion Hindrance: 150 Mesh Screen, % thru 8.0 25.3 100 9.7 100 100 40 100 Solids on Screen, ppm 2,231 254 33.3 652 31 33 51 48 700 Mesh Screen, time, sec. - > 1200 610 - > 1200 > 1200 > 1200 > 1200 % thru - 0.83 100 - 40 12.3 2.0 6.2 Solids on Screen, ppm - 30,000 54 - 111 681 2,875 3,984 Centrifugible Solids, wt.% 8.5 34.0 0.56 3.3 0.7 1.1 1.2 1 As seen, Example 227 demonstrates that a 30/70 acrylonitrile/styrene anchor portion is to be preferred for a 40/60 acrylonitrile/styrene polymer/polyol.

However, as seen from Examples 228 and 232, anchor portion compositions with increasing acrylonitrile content up to 80/20 provide polymer/polyols with satisfactory viscosity and centrifugible solids contents at the stabilizer levels used.

EXAMPLES 233-240 These Examples show the effect on the stability of a polymer/polyol prepared from a 20/80 acrylonitrile/styrene monomer system of varying the composition (i.e.acrylonitrile/styrene ratio) of the anchor portion. The solvatable portion was made by condensing polypropylene oxide material III with acrylic acid.

The experimental conditions and results are contained in Table XXIX, the base polyol used being Polyol 1: TABLE XXIX Example No. 233 234 235 236 237 238 239 240 Preparation Reaction Temperture, C. 120 120 120 120 120 120 120 120 AZO conc., wt. % 1 1 1 0.78 1.0 0.78 0.78 0.78 Stabilizer Anchor Portion, Acrylonitrile Styrene ratio 10/90 20/80 30/70 40/60 50/50 60/40 70/30 80/20 Stabilizer, wt. % 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 Ratio of Acrylonitrile/Styrene 20/80 20/80 20/80 20/80 20/80 20/80 20/80 20/80 Monomers, wt. % 20 20 20 20 20 20 20 20 Residual Acrylonitrile, % 0.08 0.09 0.03 0.10 .14 0.16 0.14 0.15 Styrene, % 1.84 1.94 2.94 2.37 2.39 2.42 2.45 2.57 TMSN, % 0.5 0.5 0.58 0.43 0.52 0.44 0.37 0.43 Toluene, % - - - - - - - Conversion, Acrylonitrile, % 98.0 97.7 99.2 97.4 96.4 95.9 96.4 96.2 Styrene, % 88.2 87.6 81.1 84.7 84.7 84.3 84.3 83.5 Combined, % 90.2 90.2 84.8 87.2 87.1 86.6 86.7 86 Total Polymer in Product, % 17.6 17.4 16.5 17.0 17.0 16.9 16.9 16.8 Product Properties Viscosity (Brookfield), 25 C., cps 3,950 1,228 830 890 1,076 2,088 1,228 1,632 Filtration Hindrance: 150 Mesh Screen, % thru 68.3 100 43 100 - 0.6 2.8 0.8 Solids on Screen, ppm 306 34 725 44 - 225,975 163,253 86,000 700 Mesh Screen, time, sec. > 1200 > 1200 > 1200 > 1200 - - - % thru 13.3 2.7 0.33 9.7 - - - Solids on Screen, ppm 172 1406 281,560 284 - - - Centrifugible Solids, wt. % 44.2 10.9 30.0 1.3 0.38 61.4 51.6 53.6 The centrifugible solids characteristics of the polymer/polyols prepared in Examples 236 and 237 in comparison to the other Examples indicate that, for optimum stabilization, an anchor portion of 40/60 to 50/50 acrylonitrile/styrene is to be preferred.

EXAMPLES 241-243 These Examples demonstrate the stabilization in a 40/60 A/S ratio polymer/polyol by a stabilizer wherein the anchor portion comprises acrylonitrile and a comonomer other than styrene. The solvatable portion was formed by condensing polypropylene oxide material III with acrylic acid.

Experimental conditions and results are contained in Table XXX, the base polyol used being Polyol 1: TABLE XXX Example No. 241 242 243 Preparation Reaction Temperature, OC. 120 120 120 AZO conc., wt. % 1 1 1 Stabilizer Anchor Portion, Acrylonitrile/Comonomer ratio (a) 40/60(1) 40/60(2) 40/60(3) Stabilizer, wt. % 1.3 1.3 1.3 Ratio of Acrylonitrile/Styrene in Monomer System 40/60 40/60 40/60 Monomers, wt. % 20 ~ 20 20 Residual Acrylonitrile, % 0.28 0.43 0.38 Styrene, % 0.34 0.34 0.25 TMSN, % 0.47 0.43 0.49 Toluene, % 3.28 3.34 3.48 Conversion, Acrylonitrile, % 96.3 94.3 95.0 Styrene, % 97.0 97.0 97.8 Combined, % 96.7 95.9 96.7 Total Polymer in Product, ",', 19.1 18.9 19.0 Product Properties Viscosity (Brookfield), 25"C., cps 1,200 3,110 3,700 Filtration Hindrance 150 Mesh Screen, % thru 100 5 4.3 Solids on Screen, ppm 71 2,269 1,558 700 Mesh Screen, time, sec. 1200 - - %thru 4.5 - Solids on Screen, ppm 944 - - Centrifugible Solids, wt. % 1.4 6.48 49.5 (a) Comonomer was: (1) ethylacrylate, (2) methylmethacrylate and (3) vinyl acetate.

The data indicates that optimum stabilization is achieved using ethyl acrylate as the comonomer for the anchor in preference to the other comonomers used.

EXAMPLES 244-249 These Examples show the preparation of stabilizers of the present invention in the equipment described in connection with Examples 119-124, followed by the use of the thus-prepared stabilizers to form polymer/polyols in the same equipment.

The experimental conditions and results are set forth in Table XXXI, the solvent, solvatable portion and catalyst being added as one stream and the monomers used being added as the other stream: TABLE XXXI Example No. 244 245 246 Preparation Solvatable Portion of Stabilizer Polypropylene oxide (1) Polypropylene oxide /material V material V Amount of Solvatable Portion, wt. % in total feed 23.49 21.903(2) 24.18 Amount of Solvent (Toluene), wt. % in total feed 46.99 65.754 48.35 Catalyst Type TBPO TBPO Di-t-butyl peroxide Catalyst Conc., wt. % in total feed 1.4 1.8 1.45 Ratio of Acrylonitrile to Styrene for anchor portion, wt. % 50/50 30/70 30/70 Total Monomer Content, wt. % in total feed 28.11 10.51 26.02 Ratio of Vinyl Monomers to Solvatable Portion in Feed 54.48/45.52 32.43/67.57 51.83/48.17 Reaction Temperature, C. 135-140 125 140 Toluene+Solvatable Portion+ Catalyst Feed Rate, gm/hr 1087 1635 1055 Monomer Feed Rate, gm/hr 425 192 371 Residual Acrylonitrile, % 5.34 1.53 Styrene, % 2.45 3.76 ConversionAcrylonitrile, % 61.40 52.41 - Styrene, % 82.29 49.87 Combined, % 77.21 50.63 Total Poly A in Unstripped Product by Calc., wt. % 9.37 1.74 Total Poly S in Unstripped Product by Calc., wt. % 12.56 3.87 Total Polymer in Unstripped Product by Calc., wt. % 21.93 5.61 Ratio of Vinyl Polymer to Soluble Portion by Calc., wt. % 46.22/53.78 20.41/79.6 Properties Solids (Nonvolatiles), wt. % (by analysis) 44.66 29.33 40.09 Calculated Solids (nonvolatiles), wt. % 44.39 27.22 Remarks Stable Stable Stable (1) Reaction product of 2 mmoles of a polypropylene oxide-butanol adduct of about 2550 molecular weight and 1 mole of TDI in toluene.

(2) On solvent-free basis.

The thus formed stabilizers were then used to form acrylonitrile/styrene polymer/polyols in the same equipment. A blend of the stabilizer and the polyol was added as one stream and the monomer system and catalyst were added as the other stream, The experimental conditions and results are set forth in Table XXXII: TABLE XXXII Example No. 247 248 249 Preparation Type of Polyol V (1) (1) Reaction Temperature, OC. 125 125 125 AZO, wt. % in total feed 1.3 0.8 0.64 Stabilizer, Example 246 247 248 Stabilizer, wt. % in total feed 4.63 5.62 5.27 Monomer+AZO Content in Feed, wt % 21.27 32.55 29.8 Ratio of Acrylonitrile to Styrene, wt. % 30/70 40/60 40/60 Polyol+Stabilizer Feed Rate, gm/hr (2) 2198 1890 1946 Monomer+AZO Feed Rate, gm/hr 594 916 826 Product Weight, gm/hr 2778 2806 2752 material Balance,% 99.5 99.71 99.28 Residual Acrylonitrile, % 0.77 1.23 1.44 Styrene, % 2.29 1.30 1.73 TSMN, % 0.61 0.41 0.28 Conversions, Acrylonitrile, % 87.21 90.34 87.74 Styrene, % 83.71 93.20 90.18 Combined, % 84.76 92.06 89.21 Total Poly A in Product by Calc., wt. % 5.40 11.78 11.51 Total Poly S in Product by Calc., wt. % 12.09 18.23 17.75 Total Polymer in Product by Calc., wt. % 17.49 30.01 29.26 Properties Brookfield Viscosity at 250C., cps. 1010 2336 1928 Calculated Hydroxyl No., mg. KOH/gm 43.92 36.75 37.38 Filtration Hindrance: 150 Mesh Screen, % through 100 100 100 solids on screen, ppm 65 28 49 700 Mesh Screen, time, sec. 227 1200 800 ",', through 100 67.66 100 solids on screen, ppm 29 79 12 Centrifugible Solids, wt. % (7) 1.47 2.82 2.43 (1) 85/15 blend of a (a) polypropylene oxide trial having 8% internal ethylene oxide content, a number average molecular weight of about 2700 and a hydroxyl number of about 62, and (b) 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.

(2) Solvent was stripped from the stabilizer in Examples 247 and 248 after blending with the polyol. In Example 249, the stabilizer was used without stripping the solvent.

In each Example, as can be seen, the polymer/polyol produced was stable.

EXAMPLES 250258 These Examples illustrate the physical appearance of the stabilizers of the present invention and their viscosity characteristics.

Table XXXIII sets forth the experimental conditions and results for a series of stabilizers made in toluene from various solvatable and anchor portions: TABLE XXXIII Example No. 250 251 252 253 254 255 256 257 Preparation (1) Solvatable Portion (2) (3) (4) (2) (4) (4) (4) (4) Anchor portion, A/S Ratio 70/30 50/50 50/50 30/70 30/70 30/70 30/70 30/70 Anchor portion/ Solvatable portion 40/6 51/49 54.5/44.5 32.4/67.6 50/50 30/7 52/48 43/57 Solid Content,% 33.5 43.2 44.66 29.33 51.5 30.5 40 43 Properites Appearance of Product (solvent free) paste paste paste semisolid semisolid semisolid solid solid Brookfield Viscosity - 160,200 cps. - - - - (1) The stabilizers of Examples 250 and 254 were prepared by the general technique previously described while the other stabilizers were made using the technique described in connection with Examples 244-249.

(2) Described in Example 245.

(3) Polypropylene oxide triol (b) described in Examples 248 and 249.

(4) Polypropylene oxide material V.

As shown, the physical appearance of the stabilizers, all made by the free radical grafting mode, varied from solids or semi-solids (Examples 253-257) 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 250252). 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 Examples 244249. The experimental conditions and results are set forth in Table XXXIV: TABLE XXXIV Example No. 258 Solvatable Portion of Stabilizer (1) Amount of Solvatable Portion, wt. % in total feed 24.31 Amount of Solvent (Toluene), wt. % in total feed 48.62 Catalyst Type TBPO Catalyst, wt. % in total feed 1.46 Ratio of Acrylonitrile to Styrene, wt. % 50/50 Total Monomer Content, wt. % in total feed 25.61 Ratio of Vinyl Monomers to Solvatable Portion in Feed 51.3/48.7 Reaction Temperature, "C. 130 Toluene+Solvatable Portion+Catalyst Feed Rate, gm/hr 1255 Monomer Feed Rate, gm/hr 432 Product Rate, gm/hr 1672 Material Balance, % 99.10 Residual Acrylonitrile, % 4.39 Styrene, % 3.04 Conversions, Acrylonitrile, % 66.20 styrene, % 76.47 Combined, % 71.24 Total Poly A in Unstripped Product by Calc., wt. % 9.12 Total Poly S in Unstripped Product by Calc., wt. % 10.57 Total Polymer in Unstripped Product by Calc., wt. % 19.69 Ratio of Vinyl Polymer to Soluble Portion by Calc., wt. % 42.87/57.13 Calculated Hydroxyl No. of Unstripped Product, mg. KOH/gm 7.47 Total Poly A on (Toluene-Free) Product by Calc., wt. % 19.86 Total Poly S in Stripped (Toluene-free) Product by Calc., wt. % 23.01 Total Polymer on Stripped (Toluene-free) Product by Calc., wt. % 42.87 Ratio of Poly A to Poly S in Product, by Calc., wt. % 46.3/53.7 Solids (nonvolatiles), wt. % by analysis 43.82 Solids (nonvolatiles), wt. % by calculation 45.94 Properties Appearance Stable Dispersion Viscosity 260,000 cps.

(I) Same as used in Example 251.

In evaluating the stabilizer of Example 258, 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, one employing a 30/70 acrylonitrile/styrene monomer system with a monomer content of about 18% in Polyol V and the other using a 40/60 acrylonitrile/styrene system at a monomer content of about 28% in the polyol blend described in Examples 248 and 249. The process used was that described in Examples 119-124; and both polymer/polyols were stable as determined by their viscosity, centrifugible solids level and filtration hindrance characteristics.

The stabilizer of Example 258 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 (46)

WHAT WE CLAIM IS:

1. A process for producing a fluid, stable polymer/polyol composition which comprises: adding a preformed stabilizer, which is a graft or addition copolymer of (a) an anchor portion consisting of a co-polymer 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 formed, and (b) a solvatable portion consisting of a propylene oxide polymer having a number average molecular weight of at least 800, the said preformed stabilizer having a viscosity in excess of 40,000 centipoises at 25"C, to a normally liquid polypropylene oxide polyol having a number average molecular weight of at least 400 and a hydroxyl number of from 20 to 280, the said preformed stabilizer being present in the polyol in an amount sufficient to stabilize the subsequently formed polymer particles dispersed therein against phase separation, in order to provide a homogeneous mixture of the preformed stabilizer and the polyol, and subsequently polymerizing a reaction mixture comprising (I) the said homogeneous mixture of preformed stabilizer and polyol, (II) from 10 to 40 weight percent of an ethylenically unsaturated monomer or a mixture of such monomers, the said weight percent being based on the total weight of the monomer or monomer mixture and the polyol in the homogeneous mixture and (III) a free radical catalyst, wherein the structure and the relative proportions of the monomers used for (a) and for (II) and the relative proportions of (a) and (b) are so chosen that a fluid, stable polymer/polyol composition is obtained.

2. A process as claimed in claim I wherein the reaction mixture comprises at least 30 weight percent of the monomer or mixture thereof.

3. A process as claimed in claim 1 or claim 2 wherein the polyol has a hydroxyl number of from 30 to 70.

4. A process as claimed in claim 1 or claim 2 wherein the polyol has a hydroxyl number of from 50 to 150.

5. A process as claimed in any one of the preceding claims wherein the preformed stabiliser has a viscosity in excess of 60,000 centipoises at 250C.

6. A process as claimed in any one of the preceding claims wherein the polyol has a number average molecular weight of less than 2000.

7. A process as claimed in any one of the preceding claims wherein the ethylenically unsaturated monomers are, individually acrylonitrile, styrene, ethyl acrylate, vinyl acetate, methyl methacrylate or acrylic acid.

8. A process as claimed in any one of the preceding claims wherein the reaction mixture comprises a mixture of two of the said monomers.

9. A process as claimed in claim 8 wherein one of the monomers is acrylonitrile which is present in an amount of less than 30 percent by weight of the total monomer weight in the reaction mixture.

10. A process as claimed in claim 8 or claim 9 wherein wherein one of the monomers is acrylonitrile which is present in an amount of from S to 15 percent of the reaction mixture.

II. A process as claimed in any one of the preceding claims wherein the reaction mixture comprises a mixture of a first monomer which forms a polymer soluble in the first monomer and a second monomer which forms a polymer insoluble in the second monomer.

12. A process as claimed in claim 10 wherein the reaction mixture comprises a mixture of acrylonitrile and styrene.

13. A process as claimed in claim 12 wherein all or at least part of the styrene is replaced by methyl methacrylate.

14. A process as claimed in any one of the preceding claims wherein the first monomer is acrylonitrile.

15. A process as claimed in claim 14 wherein the weight ratio of the first monomer to the second monomer is in the range of from 30/70 to 80/20.

16. A process as claimed in claim 14 or claim 15 wherein the second monomer is styrene, ethyl acrylate, vinyl acetate, or methyl methacrylate.

17. A process as claimed in any one of the preceding claims wherein the solvatable portion has a number average molecular weight of at least 1800.

18. A process as claimed in claim 17 wherein the solvatable portion has a number average molecular weight of at least 2600.

19. A process as claimed in any one of the preceding claims wherein the polypropylene oxide polymer has ethylenic terminal unsaturation, on the average, at no more than one end of the polymer.

20. A process as claimed in any one of the preceding claims wherein the solvatable portion is a reaction product of a polypropylene oxide polymer and an organic compound containing a group which enhances hydrogen abstraction.

21. A process as claimed in claim 20 wherein the organic compound is toluene diisocyanate.

22. A process as claimed in any one of the preceding claims wherein the stabilizer is present in an amount of at least 1 percent, based on the total weight of the resulting polymer/polyol.

23. A process as claimed in claim 22 wherein the stabilizer is present in an amount of from 1 to 6 percent, based upon the total weight of the resulting polymer/polyol.

24. A process as claimed in any one of the preceding claims wherein the reaction mixture consists of a mixture of acrylonitrile and styrene in a weight ratio of from 30/70 to 60/40, and wherein the anchor portion is formed from a mixture of acrylonitrile and styrene in a weight ratio of from 30/70 to 50/50.

25. A process as claimed in claim 24 wherein the anchor portion weight ratio is from 30/70 to 40/60.

26. A process as claimed in any one of claims I to 23 wherein the reaction mixture consists of a mixture of acrylonitrile and styrene in a weight ratio of from 0/100 to 30/70, and wherein the anchor portion is formed from a mixture of acrylonitrile and styrene in a weight ratio of from 40/60 to 50/50.

27. A process as claimed in any one of claims I to 23 the reaction mixture consists of a mixture of acrylonitrile and styrene in a weight ratio of from 60/40 to 100/0, and wherein the anchor portion is formed from a mixture of acrylonitrile and styrene in a weight ratio of from 50/50 to 80/20.

28. A process as claimed in 'claim 27 wherein the mixture of monomers in the reaction mixture consists of acrylonitrile and styrene in a weight ratio of from 60/40 to 80/20.

29. A process as claimed in any one of claims 1 to 23 wherein the reaction mixture consists of a mixture of acrylonitrile and styrene in a weight ratio of about 20/80, and wherein the anchor portion is formed from a mixture of acrylonitrile and styrene in a weight ratio of about 50/50.

30. A process as claimed in any one of claims 1 to 23 wherein the reaction mixture consists of a mixture of acrylonitrile and styrene in a weight ratio of about 30/70, and wherein the anchor portion is formed from a mixture of acrylonitrile and styrene in a weight ratio of about 50/50.

31. A process as claimed in any one of claims I to 23 wherein the reaction mixture consists of a mixture of acrylonitrile and styrene in a weight ratio of about 40/60 and wherein the anchor portion is formed from a mixture of acrylonitrile and styrene in a weight ratio of about 30/70.

32. A process as claimed in any one of claims 1 to 23 wherein the reaction mixture consists of a mixture of acrylonitrile and styrene in a weight ratio of about 50/50, and wherein the anchor portion is formed from a mixture of acrylonitrile and styrene in a weight ratio of about 30/70.

33. A process as claimed in any one of the preceding claims wherein the free radical catalyst is an azo catalyst.

34. A process as claimed in claim 33 wherein the azo catalyst is azobisisobutyronitrile.

35. A process as claimed in any one of the preceding claims when performed under the reaction conditions recited in claim I of British Patent Specification No.

1412797.

36. A process as claimed in claim 1 substantially as hereinbefore described.

37. A process as claimed in claim 1 substantially as hereinbefore described in any one of Examples 8 to 119, 122, 125 to 173, 176, 177, 190, 192 to 243, 247 to 248, or 258.

38. A polymer/polyol when produced by a process as claimed in any one of the preceding claims.

39. A method of producing a polyurethane which comprises reacting a mixture comprising (a) a polymer/polyol as claimed in claim 38 and (b) an organic polyisocyanate, in the presence of (c) a catalyst for the reaction of (a) and (b) to produce' the polyurethane.

40. A method as claimed in claim 39 wherein the reaction mixture includes (d) a blowing agent and (e) a foam stabilizer.

41. A method as claimed in claim 40 wherein the blowing agent is water and the water is used in an amount sufficient to provide a foam having a density of less than 1.75 pounds per cubic foot.

42. A method as claimed in any one of claims 39 to 41 wherein the reaction mixture includes a foam stabilizer.

43. A method as claimed in claim 39 substantially as hereinbefore described.

44. A method as claimed in claim 39 substantially as hereinbefore described in any one of Examples 181 to 183, 190, or 258.

45. A polyurethane when produced by a method as claimed in any one of claims 39 to 44.

46. A manufactured article when made from or comprising a polyurethane as claimed in claim 45.