This invention relates to particulate polymers, stabilizer compounds and compositions prepared therefrom. A process for preparing the particulate polymer and its use in forming compositions, especially stable dispersions suitable for incorporating into other polymer matrices, particularly those comprising urethane and/or urea linkages, such as flexible foams, is

10 disclosed.

Polyurethane polymers, especially foams, with improved mechanical properties (particularly tensile strength and hardness) can be prepared by reacting an 15 organic polyisocyanate with an isocyanate-reactive composition where at least one component comprises a stable dispersion.

Typically the dispersion consists of a poly-

20 urea or polyhydrazo-dicarbonamide which is prepared by reacting a diisocyanate with difunctional primary or secondary amines, hydrazines or hydrazides in polypro¬ pylene glycol ethers. Such processes are described in ftft the literature in, for example, U.S. Patents 3.325,421

and 4,089,835, German Patent DE 2,513,815 and are ex¬ tensively reviewed by K. G. Spitler and J. J. Lindsey, Journal of Cellular Plastics. Vol. 17, p. 43 (1981). Comple¬ mentary to these dispersions are those polyisocyanate- -derived polyurea dispersions in aromatic polyisocya- nates such as disclosed by patent GB 2,127,031.

To date, all polyurea dispersions in either polyether polyols or organic polyisocyanates involve the handling of organic polyisocyanates in the preparation of the particulate matter of such dispersions. Polyiso¬ cyanates are relatively expensive starting materials and also toxic compounds which have to be handled with care.

Accordingly, it would be desirable to provide a process for the preparation of a stable polyurea dis¬ persion which does not involve the use of an organic polyisocyanate. By stable, it is understood that the dispersion can be stored for an extended period, at least 2 weeks, preferably at least one month and up to 6 months, and subjected to normal fluctuations of room temperature without the dispersed particulate polymer agglomerating or solidifying to any significant degree, thus preventing its further use. Some sedimentation of the particulate solid may take place during storage, but this can readily be redispersed on agitation.

It is known that polyhydroxyalkyl monoureas can be synthesized by reacting urea with a polyhydroxylamine as already described in, for example, U.S. Patents 3,560,564 and 4,546,121, German Patent 1,463,398, German Offenlegungsschrift 2,703,185 and British Patent 1,127,605. Such prepared monoureas, especially trishy- droxyalkyl monoureas, are frequently liquids and form

stable liquid dispersions in polyols at room tempera¬ ture. These dispersions find value as reactive flame- -proofing recompounds in polyurethane foams.

It is therefore an objective of this invention to develop a discrete particulate polymer and polyahl compositions therewith for improving the mechanical properties of polymer matrices, especially those com¬ prising urethane and/or urea linkages such as flexible

10 foams. A further objective is to provide a process for the preparation of such a discrete particulate polymer which does not require the use of an organic polyisocyanate.

15 In one aspect, this invention is a solid particulate polymer comprising

1. a backbone containing (a) a plurality of moieties selected

20 from alkylene, arylene, aralkylene, alkylarylene, cycloalkylene, alkyleneoxy, and polyalkyleneoxy;

(b)a plurality of moieties selected ftj. from internal urea, thiourea, biuret and dithiobiuret; and

2. end groups selected from urea, thiourea, biuret and dithiobiuret.

30 In a second aspect, this invention is a polymeric stabilizer compound containing a plurality of aminothiocarbonyl moieties which is the reaction product of

(a) a partially aminated poly(alkylene glycol) and/or an aminated monoalkylene glycol;

(b)one or more carbonyl- or thiocarbonyl- containing compounds selected from a urea compound, a biuret compound, a thiourea compound and a dithiobiuret compound; and (c)one or more polyamines, at an elevated temperature sufficient to cause the reaction between (a), (b), and (c) to form the stabilizer compound.

In a third aspect, this invention is a urethane/urea polymer, such as a flexible polyurethane foam, characterized in that the polymer was prepared in the presence of a stable dispersion of (b) in (a) which comprises

(a) a continuous phase; and

(b) from 0.1 to 50 weight percent by total weight of (a) and (b) of a discrete particulate polymer which has an average particle size of about 30 microns or less,

characterized in that (b) is a product containing a plurality of moieties selected from internal urea, thiourea, biuret and dithiobiuret, which is the result of a reaction that comprises contacting

(c) one or more carbonyl- or thiocarbonyl-containing compounds selected from urea compounds, biuret compounds, thiourea compounds, or dithiobiuret com¬ pounds; and

(d) one or more polyamines.

In a fourth aspect, this invention is a stable dispersion of (b) in (a) which comprises

(a) a continuous phase; and

(b) from 0.1 to 50 weight percent by total weight of (a) and (b) of a discrete particulate polymer which has an average particle size of about 30 microns or less,

characterized in that (b) is a product containing a plurality of aminocarbonyl moieties or aminothiocarbonyl moieties which is the result of a reaction that com¬ prises contacting

(c) one or more carbonyl- or thiocar- bonyl-containing compounds selected from a urea compound, a biuret compound, a polycarboxylic acid compound or its ester or anhydride, a polycarboxylic acid chloride, a thiourea compound, a dithiobiuret compound, a polythiocarboxylic acid or its ester or anhy¬ dride, and a polythiocarboxylic acid chlo¬ ride; and

(d) one or more polyamines.

In a fifth aspect, this invention is a process for preparing a particulate polymer containing a plurality of aminocarbonyl moieties or aminothiocarbonyl moieties that comprises contacting

(c) one or more carbonyl- or thiocar- bonyl-containing compounds selected from a

urea compound, a biuret compound, a polycarboxylic acid compound or its ester or anhydride, a polycarboxylic acid chloride, a thiourea compound, a dithiobiuret compound, a polythiocarboxylic acid or its ester or anhy¬ dride, and a polythiocarboxylic acid chlo¬ ride; and

(d) one or more polyamines

at an elevated temperature sufficient to cause the polymerization of (c) and (d) to form the particulate polymer, in a continuous phase in which the particulate polymer is insoluble.

Surprisingly, it has been found that particu¬ late polymer as described hereinabove can be prepared as a stable dispersion in a continuous phase. The so- -prepared particulate polymer can be isolated from the continuous phase and redispersed in the same or different continuous phase to produce a different stable dispersion. The stable dispersion can be used in poly¬ mers comprising urea and/or urethane linkages to enhance their physical properties. The particulate polymer is particularly useful as a processing aid and a reinforcing filler in flexible polyurethane/urea foams. The particulate polymers of the invention also possess an unexpected relatively high aspect ratio, which advantageously provides enhanced structural reinforcement in a polymer matrix.

In one aspect this invention is a solid particulate polymer containing a plurality of urea, thiourea, biuret, and dithiobiuret internal moieties and end groups, as set forth above. The particulate polymer

can be a variety of shapes and sizes depending on the nature of the starting materials employed in its preparation and the conditions of preparation. The shape of the particulate polymer may be an irregular and amorphous shape or well defined rods, needles, fibers, fiber bundles or spheres. Preferably, the particulate polymers are rod-like, fibrous, or fibrous bundle structures. The size and shape of the particulate polymer can readily be observed by conventional techniques such as, for example, electron microscopy. Preferably, the particulate polymer has an average size of about 30 microns or less, more preferably about 25 microns or less and most preferably about 15 microns or less. Preferably, the particulate polymers have an aspect ratio of 5 or greater. The term "aspect ratio" as used herein, refers to the ratio of the length of a particle to the diameter of the particle. When particulate polymers are prepared where the average particle size is in excess of these values they may not provide for compositions which are stable dispersions or they may not provide for the desired physical properties in an end application.

Again, depending on the starting materials employed, conditions of preparation or subsequent blending with other, similarly defined, particulate polymer, the composition may contain a multi-modal particle size distribution. The multi-modal size dis- tributions may be bi-modal or tri-modal with one or a variety of particle shapes.

The particulate polymer is further character¬ ized in that it contains a plurality of urea, biuret, thiourea, or dithiobiuret moieties or mixtures thereof.

The particulate polymer preferably contains a plurality of urea and biuret groups, with urea being the most preferred. By the term plurality, it is understood that the particulate polymer contains on average more than one of such urea, biuret, thiourea, or dithiobiuret moieties.

As mentioned above, this invention is, in one aspect, a solid particulate polymer comprising

10 1. a backbone containing

(a) a plurality of moieties selected from alkylene, arylene, aralkylene, alkylarylene, cycloalkylene, alkyleneoxy, and -.j- polyalkyleneoxy;

(b)a plurality of moieties selected from internal urea, thiourea, biuret and dithiobiuret moieties; and

2. end groups selected from urea, 0 thiourea, biuret and dithiobiuret.

When the solid particulate polymer is difunctional, it can be represented by the following equation: 5

0 where: X = independently in each occurrence

NH ₂ C(0)NH-, NH ₂ C(S)NH-, NH ₂ C(0)NHC(0)NH-, or NH ₂ C(S)NHC(S)NH-;

Y = independently in each occurrence -NHC(0)NH-, -NHC(S)NH-, -NHC(0)NHC(0)NH-, or -NHC(S)NHC(S)NH-;

R = independently in each occurrence alkylene, arylene, aralkylene, alkylarylene, cycloalkylene, alkyleneoxy, or polyalkyleneoxy; and

n = an integer from 2 to 250.

10

The R groups can have a higher functionality than 2 and produce a branched and/or crosslinked polymer.

-, _£ - The backbone and end groups of these particulate polymers render them essentially neutral. This is important in applications where any residual basicity from tha amine groups present can interfere with catalytic activity. However, a small amount of 0 residual amine is acceptable in some applications.

Preferably, at least 95 percent of the starting amine is converted to neutral urea moieties.

The structure of these particulate polymers can 5 be determined by spectrometric techniques such as scanning electron microscopy (SEM), infrared spectroscopy and nuclear magnetic resonance (NMR) spectroscopy. If the particulate polymers are prepared in a dispersion, they may be isolated from the

30 dispersion for analysis by dissolving and washing away the reaction medium using methanol, and then drying the particulate polymer. Carbon-13 NMR is particularly useful, where the carbonyl carbon atoms of terminal carbonyls and internal carbonyls are clearly distinguishable. This technique also provides a means

to estimate polymer molecular weight. SEM is particularly useful to analyze the polymer morphology and aspect ratio.

The particulate polymers are insoluble in most solvents. However, many of these polymers are soluble in strong acids, such as methanesulfonic acid and sulfuric acid.

The molecular weight of the particulate polymer is preferably at least about 400, more preferably at least about 750, and most preferably at least about

1,000; and is preferably no greater than about 100,000, more preferably no greater than about 75,000, and most preferably no greater than about 50,000.

The solid particulate polymer of the invention may be prepared by a reaction that comprises contacting

(c) one or more carbonyl- or thiocar- bonyl-containing compounds selected from urea compounds, biuret compounds, thiourea compounds, and dithiobiuret compounds; and

(d) one or more polyamines in a continuous phase.

The particulate polymer is prepared by con¬ tacting reactant (c), one or more carbonyl-containing or thiocarbinyl-containing compounds selected from urea compounds, biuret compounds, thiourea compounds, or dithiobiuret compounds, with reactant (d), a polyamine, at an elevated temperature sufficient to cause the polymerization of (c) and (d) resulting in a particulate polymer. The polymerization is effected in a continuous phase in which the particulate polymer is preferably

substantially insoluble at ambient temperature. By "substantially insoluble" it is meant that the solubil¬ ity of the polymer having a plurality of urea, biuret, thiourea, or dithiobiuret moieties is such that phase separation occurs resulting in the appearance of "solid", particulate polymer. If the temperature of the continuous phase is too high or too low and/or the concentration of the particular polymer material insufficient, then phase separating may not be observed. Optionally, the continuous phase contains, if required, an effective amount of a stabilizer compound.

Suitable compounds for preparing the particulate polymer of the invention include urea compounds, biuret compounds, thiourea compounds, dithiobiuret compounds, and mixtures thereof.

Urea compounds suitable for use in preparing the particulate polymer of the invention include urea, methyl urea, ethyl urea, n-butyl urea, 1,3-dimethyl urea, 1,1-dimethyl urea, 1,3-diethyl urea, 1-methyl-1 -ethyl urea, 1,1-dibutyl urea, 1,3-dibutyl urea, n-hexyl urea, phenyl urea and diphenyl urea. Urea is the more preferred urea compound.

Thiourea compounds suitable for use in preparing the particulate polymer of the invention include thiourea, methyl thiourea, ethyl thiourea, n-butyl thiourea, 1,3-dimethyl thiourea, 1,1-dimethyl thiourea, 1,3-diethyl thiourea, 1-methyl-1-ethyl thiourea, 1,1-dibutyl thiourea, 1,3-dibutyl thiourea, n-hexyl thiourea, phenyl thiourea and diphenyl thiourea. Thiourea is the more preferred thiourea compound.

Biuret compounds suitable for use in preparing the particulate polymer of the invention include biuret, thiobiuret, 1-methyl biuret, 1,5-dimethyl biuret, 1-ethyl biuret, 1,1-dimethyl biuret, 1-methyl-5-ethyl biuret, 1-hexyl biuret, phenyl biuret and diphenyl biuret. Biuret is the more preferred biuret compound.

Dithiobiuret compounds suitable for use in preparing the particulate polymer of the invention include dithiobiuret, 1-methyl dithiobiuret, 1,5- -dimethyl dithiobiuret, phenyl dithiobiuret and diphenyl dithiobiuret. Dithiobiuret is the more preferred compound.

The most preferred compounds for use in preparing the particulate polymer of the invention are urea and biuret.

Suitable polyamine compounds for preparing the particulate polymer of the invention include polyamines which comprise at least two amino groups that can independently be primary or secondary amine groups. Preferably, the polyamine contains two such amine groups and hence are diamine compounds. Preferably, the amine groups of the polyamine are primary amine groups as these are more reactive to the urea, biuret, thiourea, or dithiobiuret-containing compound when preparing the particulate polymer. Suitable polyamines comprise aliphatic, araliphatic, cycloaliphatic or aromatic amines, polyaminated polyether polyols, or mixtures thereof. Preferably, when the polyamine is an ali¬ phatic, araliphatic, cycloaliphatic or aromatic amine it has a molecular weight of from 60 to 3000, preferably from 60 to 1000, and more preferably from 60 to 500.

When the polyamine is a polyaminated polyether polyol, preferably it has a molecular weight of at least about 100, preferably at least about 200, and more pref¬ erably at least about 400, but less than about 3000, preferably less than about 2000 and more preferably less than about 1000.

Preferred polyamines for preparing the partic¬ ulate polymer are diamines and include the aliphatic diamines especially Ci_- _j2 aliphatic diamines, aromatic diamines, and diaminated polyether polyols. More preferably, the polyamine is an aliphatic polyamine, and is most preferably hexamethylene-1 ,6-diamine.

Specific examples of suitable polyamines include butylenediamine, pentylenediamine, 2-methyl-1,5 -pentanediamine, hexamethylenediamine, dodecamethylene- diamine, trimethyldiaminohexane, 2,2'-bis-aminopropyl- methylamine, diethylenetriamine, triethylenetetraamine and tetraethylenepentamine, dipropylenetriamine, piper- azine, N,N'-bis-aminoethylpiperazine, triazine, 4-amino- benzylamine, 4-aminophenylethylamine, 1 ,4-diaminocyclo- hexane, phenylenediamines, naphthylenediamines, conden¬ sates of aniline and formaldehyde such as methylenedi- phenylamine including bis(4-aminophenyl)methane, tolu- enediamine, bisaminomethylbenzenes and the derivatives of the above-mentioned aromatic amines monoalkylated in one or both nitrogen atoms, and mixtures thereof. The preferred Cj _j _ι ₂ aliphatic diamines and aromatic diamines include butylenediamine, hexamethylenediamine, dodeca- methylenediamine, methylenediphenylamine, bis(4-amino- phenyl)methane and toluenediamine. Especially preferred is butylenediamine, hexamethylenediamine, methylenedi-

phenylamine, bis(4-aminophenyl)methane and toluenedi- amine.

The Cj _j _ι aliphatic diamines may contain minor quantities of C ₂ _3 diamines. Such minor quantities are less than 5, preferably less than 3, more preferably less than 1 percent by weight, and most preferably such C ₂ _3 diamines are absent.

10 The presence of such C _3 diamines in quanti¬ ties greater than these may deter from the efficient preparation of the particulate polymer.

Aminated polyether polyols may be prepared by 15 reductive amination procedures. Suitable procedures for the reductive amination of polyols are described in, for example, U.S. Patents 3,128,311; 3,152,998; 3,236,895; 3,347,926; 3,654,370; 4,014,933; and 4,153,581, the relevant portions of which are herein incorporated by

20 reference.

Exemplary of such aminated polyether polyols are those products sold under the tradename of _P5 Jeffamine™ by Texaco such as Jeffamine™ D-230 and Jeffamine™ D-400 which are aminated polyoxypropylene polyols that have molecular weights of about 230 and about 400, respectively.

0 The equivalent ratio of carbonyl- or thiocarbonyl-containing compound to polyamine compound is such so as to provide a particulate polymer which has a plurality of the hereinabove described urea, biuret, thiourea, or dithiobiuret moieties. Preferably, the equivalent ratio of compound(s) comprising component (c)

15 to polyamine is at least about 0.8:1, more preferably at least about 0.8:1, and is preferably no greater than about 1.1:1.

The particulate polymer of the invention may be prepared by contacting a compound selected from urea compounds, biuret compounds, thiourea compounds, or dithiobiuret compounds with a polyamine in a continuous phase. Suitable continuous phase materials are those

10 which permit the formation of the particulate polymer and in which the so-formed particulate polymer is substantially insoluble. Preferably, the continuous phases are those products which have boiling points equivalent to or greater than the temperature required

15 for polymerization reaction and include aromatic hydro¬ carbons, aromatic ethers, alcohols, diols; and polyols such as a polyether polyol, a polyester polyol, a poly¬ carbonate polyol; or mixtures thereof. However, continuous phase materials which have a boiling point

20 below the temperature required for the polymerization reaction may be used at elevated pressures. When a polyol is employed as the continuous phase, the hydroxyl end groups associated with the polyol are advantageously ft less reactive towards the urea, thiourea, biuret, or thiobiuret compound(s) than the polyamine present. Preferably, the continuous phase is a polyol.

Suitable polyols for use as the continuous 30 phase in the preparation of the particulate polymers of this invention are those which contain from nominally 2 to 8, and preferably from nominally 2 to 4 hydroxyl groups per molecule.

Preferably, the equivalent weight of the polyol is at least about 31, preferably at least about 100, more preferably at least about 500 and most preferably at least about 1000, but less than about 4000, preferably less than about 2500 and more preferably less than about 2000.

Polyether polyols suitable for use as the con¬ tinuous phase may be obtained in known manner by react¬

10 ing initiator compounds containing reactive hydrogen atoms with alkylene oxides, such as ethylene oxide, pro- pylene oxide, butylene oxide, styrene oxide, tetrahydro- furan or epichlorohydrin, or with mixtures of these alkylene oxides. The initiator may be reacted with 15 mixtures of alkylene oxides in either a random or block sequence.

Suitable initiator compounds containing reac¬ tive hydrogen atoms include water, ethylene glycol,

20 1,2- or 1,3-propylene glycol, 1,4- or 2,3-butylene gly¬ col, 1,6-hexanediol, 1,8-octanediol, 4-bis-hydroxyl- methyl cyclohexane, 2-methyl-1,3-propanediol, glycerine, trimethylolpropane, 1,2,6-hexanetriol, 1,2,4-butanetri- ftft ol, trimethylolethane, pentaerythritol, mannitol, sorbi- tol, methyl glucoside, sucrose, resorcinol, ammonia, methylamine, ethylene diamine, diethylene triamine, tetra- or hexamethylene diamine, ethanolamine, dietha- nolamine, triethanolamine, aniline, aniline diamine,

30 2,4- and 2,6-diaminotoluene and polyphenylpolymethylene polyamines of the type obtained by condensing aniline with formaldehyde, and such like materials.

Polyester polyols suitable for use as the con¬ tinuous phase in this present invention include reaction

products of polyhydric (preferably dihydric and, option¬ ally, trihydric) alcohols with polybasic, preferably dibasic, carboxylic acids. Alternatively, to the use of free polycarboxylic acids, it is possible to use the corresponding polycarboxylic acid anhydride or corre¬ sponding polycarboxylic acid esters of lower alcohols or mixtures thereof for producing the polyesters. The polycarboxylic acids may be aliphatic, cycloaliphatic, aromatic and/or heterocyclic and may be substituted (for example by halogen atoms) and/or unsaturated. Examples of suitable carboxylic acids include succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, trimellitic acid, phthalic acid anhydride, tetrahydrophthalic acid anhy- dride, hexahydrophthalic acid anhydride, tetrachloroph- thalic acid anhydride, glutaric acid anhydride, maleic acid, oleic acid, maleic acid anhydride, fumaric acid, dimeric and trimeric fatty acids optionally in admixture with monomeric fatty acids, terephthalic acid dimethyl ester and terephthalic acid-bis-glycol ester. Examples of suitable polyhydric alcohols include ethylene glycol, 1,2- and 1 ,3-propylene glycol, 1,4- and 2,3-butylene glycol, 1 ,6-hexanediol, 1,8-octanediol, neopentyl gly- col, cyclohexane dimethanol, 2-methyl-1 ,3-propanediol, glycerol, trimethylolpropane, 1,2,6-hexanetriol, 1,2,4 -butanetriol, trimethylolethane, triethylene glycol, tetraethylene glycol, polyethylene glycols, dipropylene glycol, polypropylene glycols, dibutylene glycol and polybutylene glycols. The polyesters may also contain terminal carboxyl groups. Polyesters of lactones such as e-caprolactam, or hydroxy carboxylic acids such as ω-hydroxycaproic acid may also be used.

Suitable polycarbonate polyols for use in the process of preparing particulate polymers and composi¬ tions of this invention are those compounds which are described in, for example, U.S. Patent 4,686,276.

The use of polyether polyols as the continuous phase is preferred, especially when such polyols contain predominant amounts of polymerized ethylene oxide and/or primary hydroxyl groups. By "predominant" it is meant that the polyol contains at least 35, preferably at least 50, and more preferably at least 60 percent pri¬ mary hydroxyl groups of its total hydroxyl group. Poly¬ ether polyols are generally less reactive towards amines than polyester or polycarbonate polyols.

In a more preferred embodiment of the inven¬ tion, when the continuous phase is a polyether polyol the polyamine used in preparing the particulate polymer of the invention comprises a combination of a Ci_ι aliphatic diamine or aromatic diamine with a diaminated polyether polyol. In such a preferred combination the aminated polyether polyol may represent up to about 80 weight percent of the the total polyamine reacting with the carbonyl-containing compound. Use of larger quan¬ tities of aminated polyether polyol may confer solubil¬ ity of the particulate polymer depending upon the ali¬ phatic or aromatic amine present.

When particulate polymer dispersions in a poly¬ ester polyol or polycarbonate polyol continuous phase are desired, it is preferable to isolate a particulate polymer prepared in some other continuous phase and re- disperse in a polyester polyol or polycarbonate polyol. However, polyester and polycarbonate polyols may be

employed as the continuous phase for the preparation of the particulate polymer when the relative reactivity of the internal ester groups of such polyols towards amine groups is such that they do not substantially interfere with the reaction of the amine groups with the urea, biuret, thiourea, or dithiobiuret compounds in the forming of the particulate polymer. In general, the interference of such ester groups may be minimized by selecting urea, biuret, thiourea, or dithiobiuret compounds which which have a higher degree of relative reactivity with amine groups. For example, biuret tends to be more reactive with an amine than urea. In addition, the interference of such ester groups may also be minimized by using lower processing temperatures.

Preferably, the particulate polymer is employed as a composition comprising a dispersion of the polymer in a continuous phase. When so employed, the composition preferably contains the particulate polymer in from at least 0.1, preferably at least about 5 and more preferably at least about 8, and up to about 50, preferably up to about 40 and more preferably up to about 30 percent by weight of the total weight of the continuous phase and particulate polymer present.

Compositions that contain lesser or greater amounts of the particulate polymer may provide any significant improvements in the physical properties of polyurethane polymers prepared therefrom, lead to viscosities too great for processing, or not be stable dispersions.

The continuous phase can comprise one or more compounds in which the particulate polymer will form a stable dispersion at ambient conditions. By "stable dispersion" it is understood that the particulate

polymer in the continuous phase will not agglomerate in, or cause to solidify, the composition to any significant degree thus preventing its further use in a desired application. Advantageously, the dispersion is stable for at least 2 weeks, preferably at least 4 weeks, and more preferably at least 12 weeks.

The particulate polymer is preferably substantially non-reactive with respect to the continuous phase. Preferably, the continuous phase is a liquid at ambient temperature, but it can also be a meltable solid such as a thermoplastic polymer or certain polyester polyols.

When the continuous phase is a liquid, the pre¬ ferred liquids are those as discussed later when defin¬ ing the continuous phase employed in the process of pre¬ paring the particulate polymer. The more preferred con¬ tinuous phases for the composition are polyahls, such as a polyether polyol, a polyester polyol, a polycarbonate polyol; or mixtures thereof. Especially preferred as continuous phase are polyether polyols because of their suitability to preparing polymer matrices containing urethane and/or urea linkages. A polyether polyol which has from nominally two to about four isocyanate-reactive hydrogen atoms per molecule and a hydroxyl equivalent weight of at least 500, and preferably from 500 to 2500, is the most preferred continuous phase for the polymer composition.

The continuous phase of the composition can be that used in a preferred process of preparing the par¬ ticulate polymer, whereby the particulate polymer is formed and dispersed in situ. In this instance, the poly-

mer composition is a product obtained directly from a process of preparing the particulate polymer in a con¬ tinuous phase, and the particulate polymer content of the composition is as obtained from the process.

When a composition containing a lower weight percentage of particulate polymer than provided for by the in situ process is desired, this may be achieved by blending in additional amounts of a continuous phase. The additional amounts of continuous phase can be either the same continuous phase as used in the preparation of the particulate polymer, or another continuous phase which is miscible with the first and compatible with the intended end use of the composition.

Compositions containing the particulate polymer at a higher weight percentage than obtained by the in situ process can be prepared by removal of some of the con¬ tinuous phase through a suitable procedure such as, for example, distillation.

Alternatively, the particulate polymer may be isolated from the continuous phase of the process of its preparation by, for example, filtration, and then blended and redispersed in a continuous phase at a desired weight content to give a stable dispersion. In this case, such continuous phases for the redispersion of the particulate polymer may be completely different from that used in the process of making the particulate polymer. Exemplary of completely different continuous phases for redispersion are thermoplastic polymers or organic polyisocyanates.

The preparation of the solid particulate polymer takes place in the continuous phase which preferably contains a stabilizer compound. The stabilizer compound serves to stabilize the particulate polymer and permits the formation of a stable dispersion in the continuous phase. Depending on the carbonyl- -containing compound, polyamine and continuous phase employed in preparing the particulate polymer composition of the invention, a stabilizer compound may or may not be required, but preferably is present. A stabilizer compound is also preferably employed when the stable dispersion of the invention is prepared where the continuous phase is different from that used in the process of making the particulate polymer or where the concentration of the particulate polymer is different from that obtained in its process, it may be advantageous to employ a stabilizer compound.

When employed, the stabilizer compound is present in a quantity sufficient to provide for a stable dispersion in a continuous phase. Preferably, such quantity is less than about 15.0, preferably less than about 10.0 and more preferably less than about 5.0 percent by weight of the combined weights of the continuous phase and particulate polymer present.

A stabilizer compound advantageously provides a chemical and/or physical means of compatibilizing the particulate polymer with the continuous phase, allowing for the formation of a stable dispersion. The stabilizer compound may be an interreactive stabilizer compound and contain a reactive functional group which can participate in the chemistry associated with the formation of the particulate polymer by reacting with

the reactants necessary for the formation of the particulate polymer. Alternatively, the stabilizer compound may be a non-interreactive stabilizer compound containing no interreactive functional group and operate by providing for physical compatibility or miscibility of particulate polymer and continuous phase. When the particulate polymer is stabilized in the continuous phase by a stabilizer compound which has a functional group that can react with the reactants necessary for the formation of the particulate polymer, the remaining part of the stabilizer compound is preferably compatible with the continuous phase. In one preferred embodiment, one part of the stabilizer compound is structurally similar to and compatible with continuous phase, while another part of the stabilizer molecule is structurally similar to and attracted to the surface of the particulate polymer.

In a second aspect, this invention is a stabilizer compound containing a plurality of urea, biuret, thiourea, or dithiobiuret moieties which is the reaction product of

(a) a partially aminated poly(alkylene glycol) and/or a fully aminated monoalkylene glycol;

(b)one or more carbonyl- or thiocarbonyl- containing compounds selected from a urea compound, a biuret compound, a thiourea compound and a dithiobiuret compound; and

(c) one or more polyamines, at an elevated temperature sufficient to cause the reaction between (a), (b), and (c) to form the stabilizer compound.

Stabilizer compounds of this type can be represented by the following general structure:

where: X = independently in each occurrence

NH ₂ C(0)NH-, NH ₂ C(S)NH-, NH ₂ C(0)NHC(0)NH-, or NH ₂ C(S)NHC(S)NH-;

Y = independently in each occurrence -NHC(0)NH-, -NHC(S)NH-, -NHC(0)NHC(0)NH-, or -NHC(S)NHC(S)NH-;

Z = the residue of a partially aminated poly(alkylene glycol) and/or a fully aminated monoalkylene glycol after removal of a terminal amine group;

R = independently in each occurrence alkylene, arylene, aralkylene, alkylarylene, cycloalkylene, alkyleneoxy, or polyalkyleneoxy; and

m = an integer from 1 to 20.

The R groups can have a higher functionality than 2 and produce a branched and/or crosslinked polymer.

Preferably, the stabilizer compound is one which contains a functional group which will react with at least one of the reaction components in the process for the preparation of the particulate polymer. Such compounds are prepared from amine and carboxylic acid

compounds, particularly monoamine and monocarboxylic acid compounds. The monoamine and monocarboxylic acid compounds are preferably high molecular weight compounds of similar composition to the continuous phase employed when preparing the particulate polymer. Preferably, the molecular weight of such a monoamine or monocarboxylic acid is at least 400, preferably at least 1000, more preferably at least 2000, and most preferably at least 4000.

Exemplary of partially aminated poly(alkylene glycols) and fully aminated monoalkylene glycols which may be used to prepare interreactive stabilizer compounds include monoamine compounds such as Texaco M-2005 (an aminated 2-methoxyethanol-initiated propylene oxide adduct which has a molecular weight of about 2000); and products which can be obtained by reductive amination of available polyether polyols. A comme¬ rcially available polyether polyol is, for example, the polyether triol, Voranol™ 4701 sold by The Dow Chemical Company which can be subjected to reductive amination giving a product which has a molecular weight of about 5000 and on average about 30 percent of its hydroxyl groups converted to amine groups, and is therefore nominally a monoamine.

A sufficient quantity of stabilizer compound is employed in the process to provide the particulate polymer as defined by the invention. Preferably, the quantity of stabilizer compound employed is at least about 0.1, preferably at least about 5.0, more prefer¬ ably at least about 10.0 and most preferably at least about 15.0, but less than about 30.0 percent by weight of total weights of (c) the carbonyl-containing com-

pound, and (d) the polyamine used in preparing the par¬ ticulate polymer. The above quantities of stabilizer compound are present in the continuous phase in less than about 15.0 percent, preferably less than about 10.0 percent, and more preferably less than about 5.0 percent by weight of the total weight of the continuous phase and stabilizer compound.

The quantities of reactants, polyamine and carbonyl-containing compound, in relation to continuous phase and optional stabilizer compound used in the pro¬ cess of preparing the particulate polymer, are such so as to provide a discrete particulate polymer in the continuous phase. Preferably, the quantities of reactants and reaction conditions are such to provide an end product from the process which contains the particu¬ late polymer in from at least 0.1, preferably at least about 5 and more preferably at least about 8, and up to about 50, preferably up to about 40 and more preferably up to about 30 percent by weight of the total weight of the continuous phase and reactants employed.

In one preferred method for the preparation of the particulate polymer, the continuous phase and optional stabilizer compound or amino precursor of the stabilizer compound are preferably introduced into a suitable reactor preferably padded with an inert atmosphere such as nitrogen. The stabilizer compound can be made in the reaction vessel just prior to particulate polymer formation or it can be made as a stabilizer compound concentrate. A portion of a concentrate batch of pre-formed stabilizer compound could then be used in subsequent particulate polymer preparations. The polyamine and carbonyl-containing

compound to be polymerized can be fed into the charged reactor in one or in a multiple of steps before and during the polymerization reaction. They may be fed as a premixed combination or independently.

An advantage of using a multiple step procedure is that it allows for the formation of a stabilizer prior to formation of the particulate polymer. The stabilizer, if desired, can be retained and subsequently used in other preparations, covered by the scope of the invention, where variables such as reactants, continuous phase or reaction conditions differ, thus giving the possibility of preparing particulate polymers having mixed compositions and/or specifically controlled particle size(s) and range(s).

To effect the polymerization of the polyamine with the carbonyl-containing compound, it is necessary to heat the contents of the reactor. The temperature needs to be sufficient to promote polymerization without being harmful to the process, reactants or products. The required reaction temperatures will be dependent on the nature of the reactants and continuous phase. Preferably, an elevated temperature of at least about 50°C, preferably at least about 80°C and more preferably at least about 100°C, and up to about 200°C, preferably up to about 175°C, more preferably up to about 150°C and most preferably up to about 135°C is employed. Use of different carbonyl-containing compounds to prepare the polymer can influence the preferred temperature ranges for operating the process. When the carbonyl-containing compound to be reacted is urea, the reaction temperature is preferably in the range of from 100°C to 175°C. When the carbonyl-containing compound is biuret then

advantageously the reaction temperature is preferably in the range of from 50°C to 150°C.

The contents of the reactor are maintained at the elevated temperature with continuous stirring until the polymerization reaction is terminated. In the case when reacting urea with a polyamine, the reaction is terminated when ammonia ceases to be evolved, or when the amine concentration (from the polyamine) as measured by, for example, titrometric procedures is seen to be constant with time. Typically, it may take up to 30 hours to reach a state of termination, but this is dependent on the type of reactants, temperature and continuous phase employed.

Although not critical to the formation of the particulate polymer, the rate or type of stirring may influence the particle size, the size distribution, and particle stability. High stirring rates under high shear conditions can favor the production of particulate polymer with smaller particle sizes.

If desired, the pressure within the reactor can be reduced below one atmosphere to promote the polymeri¬ zation reaction. At reduced pressures, reaction by- -produots such as ammonia, when urea or biuret are employed, or water when a polycarboxylic acid compound is used as the carbonyl-containing compound, or a lower alcohol when polycarboxylic acid esters of a lower alco¬ hol is used as the carbonyl-containing compound, can readily be removed encouraging formation of desired product.

If required, catalysts may be used to promote the polymerization reaction. Suitable catalysts are any basic compound which is compatible with the polymeriza¬ tion reaction, reactants and products, and include for example, sodium hydroxide, potassium hydroxide and ter¬ tiary amines such as triethylamine or N-methyl pyrroli- dine. Metal salts are also useful catalysts when poly¬ carboxylic acid esters of lower alcohols are used as the carbonyl-containing compound. Such catalysts include, for example, dibutyltin oxide, zinc oxide and titanium isopropoxide. When used, such catalysts are present in a catalytic quantity sufficient to obtain the desired increase in rate of polymerization. Preferably, when employed, the quantity of catalyst is less than about 2 percent, preferably less than about 1 percent and more preferably less than about 0.5 percent by weight of total weights of components (c), (d) and continuous phase employed in the process.

When the polymerization reaction is terminated, the product obtained is a particulate polymer dispersed in a continuous phase. The particulate polymer as a stable dispersion may be used directly in a desired application, if the continuous phase is compatible to that application.

In some preparations, the continuous phase may contain quantities of non-polymerized reactants, espe- cially polyamine. The presence of such unreacted poly¬ amine leads to the presence of amino moieties which are not desirable if the continuous phase part of the dis¬ persion is to be used directly in the preparation of, for example, polyurethane polymer matrices. Amine moi¬ eties containing hydrogen on the nitrogen center can

react with isocyanates. In addition, amine compounds can also function as catalyst in the formation of poly¬ urethane polymer and therefore their presence may pre¬ sent problems with respect to processing and reactivity.

The presence of unreacted amine moieties from the polyamines and any intermediate reaction products can be determined by suitable acid-base titration proce¬ dures. They can be removed from the continuous phase by

10 treating with an appropriate quantity of the carbonyl- -containing compound under the conditions of polymeri¬ zation. Alternatively, or in addition to this treat¬ ment, if required, any remaining amount of unreacted amine moieties can be removed by using a suitable amine 15 scavenger such as for example, benzoyl chloride or phosphoric acid. However, with both alternatives, reactants and conditions employed are chosen so as to preserve and not destroy the particulate polymer dis¬ persion in the continuous phase, and provide an end

20 product which is free of unreacted amine moieties.

Alternatively, the particulate polymer may be isolated by removing the continuous phase. The con- _pt - tinuous phase may be removed, for example, by distil¬ lation, or preferably the particulate polymer may be collected by a filtration process and dried to give a powder. This is faciliated by the addition of a solvent in which the continuous phase is soluble, but the

30 particulate polymer is insoluble. A wide variety of alcohols, esters, and other hydrocarbons are useful for this purpose, dependng on the particular continuous phase. Methanol is a preferred solvent. In this case, treatment of the continuous phase to remove or convert any residual starting material containing amino moieties

or other functional groups is optional. The particulate polymer in powder form can then be used directly in the desired applications and, for example, redispersed in a continuous phase.

In a third aspect, this invention is a urethane/urea polymer, such as a flexible foam, the polymeric matrix of which contains the particulate polymer described above. This particulate polymer is particularly useful as a processing aid and a reinforcing filler in flexible polyurethane/urea foams. The particulate polymer is preferably present in an amount sufficient to provide improved mechanical properties, such as, for example, improved load bearing, tear strength, compression set, impact strength and flexural modulus. Preferably, the particulate polymer has the shape of a rod, fiber, or fiber bundle, and preferably has an aspect ratio of 5 or greater. Preferably, the particulate polymer is present in an amount, based on the weight of the polymer, of at least about 0.1 percent, more preferably at least about 0.5 percent, and most preferably at least about 1.0 percent; and is preferably no greater than about 40 percent, more preferably no greater than about 25 percent, and most preferably no greater than about 20 percent.

The urethane/urea polymer may be prepared by adding the desired amount of particulate polymer to an isocyanate-reactive composition, which is then reacted with a polyisocyanate in the presence of a blowing compound. Processes suitable for the preparation of polyurethane foams are described, for example, in U.S. Patents 4,386,167, 4,425,468, and 4,668,734.

The following examples are illustrative of the present invention but are not to be construed as limit¬ ing the scope thereof. Unless stated otherwise, all parts and percentages are given by weight.

Example 1

This example illustrates the preparation of a stable particulate polymer dispersion by a two-step procedure involving an intermediate product.

To a silanized glass reactor is added 800 parts of a continuous phase, or polyether polyol, Voranol™ 4702 (an ethylene oxide/propylene oxide adduct of glyc- erine, equivalent weight about 1610 and primary hydroxyl content of 82 percent; sold by The Dow Chemical Com¬ pany), 1.0 part of urea, 1.12 parts of hexamethylene- -1,6-diamine and 16.0 parts of a stabilizer compound, an ethylene oxide/propylene oxide adduct of glycerine, hydroxyl equivalent weight about 1610 and primary hydroxyl content of 82 percent which has 30.6 percent of its hydroxyl groups converted to amine moieties). The reactor is purged with nitrogen and the mixture heated at 140°C to 150°C for 18 to 20 hours while continuously stirring. The resulting intermediate product is a turbid, grey liquid with a viscosity of about 1230 cps at 25°C.

To the intermediate product in the glass reac¬ tor is added a further 34 parts of urea and 65.6 parts of hexamethylene-1,6-diamine. The urea and diamine, as a mixture, are added to the reactor periodically, about every 30 minutes, in portions of 7 to 8 parts while continuously stirring and maintaining the temperature at

140°C to 150°C. The contents of the reactor are stirred until titrometric analysis shows no change in amine concentration.

The resulting particulate polymer (polyurea) in the continuous phase is then treated with a further 4.0 parts of urea, and stirred for about 20 hours at 140°C to 150°C before purging the headspace of the reactor with nitrogen to remove any non-polymerized starting material and/or volatile products.

After purging, the particulate polymer and continuous phase are treated with 1.7 parts of benzoyl chloride, to give a finished product. On cooling, the finished product is a stable particulate polyurea dis¬ persion which has a viscosity of about 2200 cps at 25°C, a particulate polymer content of about 9.1 percent by weight. The particles have the appearance of fiber bundles of 1 to 10 microns in length and have aspect ratios greater than 5.

Example 2

This example illustrates the preparation of a stable particulate polymer dispersion by a one-step procedure. All reactants are charged in one procedure, with no intermediate product being isolated.

All conditions and subsequent procedures are as for Example 1.

Details of the polyamine, carbonyl-containing compound, continuous phase and stabilizer compound are given in Table I. The particulate polymer content,

particle size, viscosity and hydroxyl number of the resulting stable particulate polymer dispersions are also given in Table I.

Examples 3 to 7

These examples illustrate the preparations of stable particulate polymer dispersions employing reac¬ tants at different concentrations. The products are prepared according to the procedure of Example 2.

Details of the polyamine, carbonyl-containing compound, continuous phase and stabilizer compound are given in Table I. The particulate polymer content, particle size, viscosity and hydroxyl number of the resulting stable particulate polymer dispersions are also given in Table I.

® Continuous Phase A is an ethylene oxide/propylene oxide adduct of glycerine; OH No. 35, primary OH 82 percent

Polyamine I is hexamethylene-l,6-diamine

® Polyamine II is Jeffamine D-400 sold by Texaco (an aminated polypropylene glycol)

® C=0, carbonyl-containing compound, for Examples 2 to 7, urea

® An ethylene oxide/propylene oxide adduct of glycerine; OH No. 35, primary Oh 82 percent which is partially aminated, 30.6 percent of hydroxyl groups converted to amine moieties

® Jeffamine M-2Q05 sold by Texaco (an aminated 2-methoxyethanol-initiated propylene oxide adduct. molecular weight 2000)

Particulate polymer content of dispersion, percent by weight

Average particle size - N.O. - Not observed

® Viscosity

Hydroxyl number

Example 8 - Isolation and Redispersion of a Particulate Polymer in a Polyether Polyol

To 160 parts of the particulate polyurea dis¬ persion obtained in Example 1 is added 500 parts of a mixture consisting of 70 volume percent isooctane and 30 volume percent toluene. The resulting slurry is stirred and then filtered using a suitable fine porosity glass filter and the particulate polyurea isolated.

The particulate polyurea is washed several times with the mixture to remove all traces of the continuous phase and then dried in a vacuum oven for about 16 hours at 120°C/<1 mm Hg to give a white powder.

A new polyurea dispersion is prepared by dis¬ persing 15 parts of the isolated white powder in 60 parts of a continuous phase, a polyether polyol, Voranol™ 4702 sold by The Dow Chemical Company.

The resulting stable polyurea dispersion pre¬ pared in this manner has a particulate polymer content of 20 percent by weight and an equivalent weight of 2040.

Example 9 and 10

Examples 9 and 10 are polymers containing urethane and/or urea linkages, prepared with the stable particulate dispersions of Examples 1 and 8, respec¬ tively. The particulate polymers have the appearance of fiber bundles of about 1 to 10 microns in length and have aspect ratios greater than 5.

The polymers prepared are plaques of 4" x 4" x

0.125" prepared according to the following procedure, with the formulations given in Table II.

All components are degassed separately under vacuum, then mixed together in a common container in the amounts specified in Table II. The mixture is vigorous¬ ly stirred with a mechanical mixer for 10 to 30 seconds and then poured into an ambient temperature steel plaque

10 mold whose surfaces have been treated with a Teflon™ -based mold release compound. The mold is closed, bolted shut, and placed in a suitable oven at 120°C for about 2.5 hours. After cooling to room temperature the part is removed from the mold, and its physical proper- 15 ties observed.

The modulus properties are summarized in Table III. Sample A is a control, containing a theoretical 30 percent (wt/wt) hard segment. Samples 9 and 10 show the

20 effect of adding 6 percent and 14 percent (wt/wt) poly¬ urea solids, respectively, to this base elastomer. Sam¬ ples B and C are controls which show the effect of add¬ ing 6 percent and 14 percent (wt/wt) hard segment to the _P5 base elastomer (Example A).

The soft segment glass transition temperature and flexural storage modulus in the glassy region (E' at -125°C) are unaffected by any of the changes. Samples B 30 and D show a definite increase in plateau modulus when the polyurea solids are added, and this increase is greater than that observed when extra hard segment is added, as in Samples B and C. Likewise, the rubbery plateau is extended to higher temperatures when the polyurea solids are present (temperature at which E' =

10 psi), and the increase is more than that observed when extra hard segment is added.

This example illustrates the properties to be obtained for a polymer matrix comprising the particulate polymer of the invention compared to a polymer matrix where it is necessary to modify substantially the com¬ ponents used in preparing the matrix to achieve the same performance.

TABLE II Elastomer Formulations

* Not an example of this invention

^® Equivalent weight = 1635 g/eq

^® 1,4-Butanediol

^® Mixture of methylene-bis(4-phenylisocyanate) and polycarbodiimide products sold by The Chemical Company

^® Dibutyltin dilaurate

^® Particulate polymer dispersion of Example 1

^® Particulate polymer dispersion of Example 8

TABLE III

Physical properties of Polyurethane Elastomers

*Not an example of this invention.

Example 11 Preparation of a Stabilizer compound

Concentrate Based on Urea, 1,6-Hexanediamine and a Partially Aminated Voranola

To a reactor is added 640 parts of a continuous phase, a polyether polyol, Voranol™ 4702 (an ethylene oxide/propylene oxide adduct of glycerine, equivalent weight about 1610 and primary hydroxyl content of 82 percent; sold by The Dow Chemical Company), 11.12 parts of urea, 11.52 parts of 1 ,6-hexanediamine, and 207.2 parts of an aminated polyether polyol (an ethylene oxide/propylene oxide adduct of glycerine, hydroxyl equivalent weight about 1610 and primary hydroxyl content of 82 percent which has been partially aminated so that 30.6 percent of its hydroxyl groups are converted to amine moieties). The reactor is purged with nitrogen and the mixture is heated to about 150°C for 20 hours. The resultant stabilizer compound

concentrate is cooled to ambient temperature and characterized and used as a stabilizer compound in subsequent urea dispersion preparations.

Example 12

This example illustrates the preparation of a stable particulate polymer dispersion using the stabilizer compound concentrate of Example 11

To a silanized glass reactor is added 742 parts of a continuous phase, a polyether polyol, Voranol™ 4702 (an ethylene oxide/propylene oxide adduct of glycerine, equivalent weight about 1610 and primary hydroxyl content of 82 percent; sold by The Dow Chemical Company) and 87 parts of the stabilizer compound concentrate of Example 11. The reactor is purged with nitrogen and the mixture is heated to about 150°C. Urea (42.26 parts) and 1 ,6-hexanediamine (81.6 parts) are ground together and well mixed in a jar in a nitrogen environment. Increments (about 10.2 parts) of the urea/1,6-hexanediamine mixture are added to the reactor over a total time of 48 hours. The contents of the reactor are stirred until titrometric analysis shows no change in amine concentration.

The resulting particulate polymer (polyurea) in the continuous phase is then treated with a further 4.1 parts of urea, and stirred for about 72 hours at about 150°C before purging the headspace of the reactor with nitrogen to remove any non-polymerized starting material and/or volatile products.

After purging, the particulate polymer and continuous phase are treated with 1.7 parts of benzoyl chloride, to give a finished product. On cooling, the

finished product is a stable particulate polyurea dispersion which has a viscosity of about 2300 cps at 25°C, a particulate polymer content of about 12.5 percent by weight. The particulate particles resemble fiber bundles of about 1 to 10 microns in length and have aspect ratios of about 10 to 20.

The following examples illustrate the use of different carbonyl-containing compounds and polyamines for preparing particulate polymers and dispersions.

Example 13 - A Particulate Polymer Com¬ position Where the Partic¬ ulate Polymer is Prepared from Urea and Bis(4-amino- phenyl)methane

To a reactor is added 100 parts of a continuous phase, a polyether polyol, VORANOL™ 4702 (an ethylene oxide/propylene oxide adduct of glycerine, equivalent weight about 1610 and primary hydroxyl content of 82 percent; sold by The Dow Chemical Company), 0.16 part of urea, 0.24 part of bis(4-aminophenyl)methane, and 2.0 parts of an aminated polyether polyol (an ethylene oxide/propylene oxide adduct of glycerine, hydroxyl equivalent weight about 1610 and primary hydroxyl content of 82 percent which has been partially aminated so that 30.6 percent of its hydroxyl groups are converted to amine moieties). The reactor is purged with nitrogen and the mixture is heated from 140°C to 150°C for 18 to 20 hours while continuously stirring. The resulting intermediate product (stabilizer) is a transparent, light orange liquid with a viscosity of about 940 cps at 25°C.

To the intermediate product in the reactor is added further 2.72 parts of urea and 8.86 parts of bis-

(4-aminophenyl)methane. The urea and diamine are added to the reactor periodically as a mixture, about every 45 minutes, in portions of about 1.5 parts by weight while continuously stirring and maintaining the temperature at 140°C to 150°C. The contents of the reactor are stirred continuously until titrometric analysis shows that the amine concentration is constant, in this case about 21 hours.

The resulting particulate polymer (polyurea) in the continuous phase is then treated with a further 1.0 part of urea, and stirred for about 40 hours at 140°C to 150°C.

On cooling, the finished product is a stable particulate polyurea dispersion which has a viscosity of about 3300 cps at 25°C. The particulate polymer content is about 9.1 percent. The particulate polymers have the appearance of spheres with diamters of from 0.1 to 15 microns.

Example 14 - A Particulate Polymer Com¬ position Where the Partic¬ ulate Polymer is Prepared from Biuret and Bis(4-amino- phenyl)methane

To a reactor is added 100 parts of a continuous phase, a polyether polyol, VORANOL™ 4702 (an ethylene oxide/propylene oxide adduct of glycerine, equivalent weight about 1610 and primary hydroxyl content of 82 percent, sold by The Dow Chemical Company), 0.25 part of biuret, 0.24 part of bis(4-aminophenyl)methane, and 2.0 parts of an aminated polyether polyol (an ethylene oxide/propylene oxide adduct of glycerine, hydroxyl equivalent weight about 1610 and primary hydroxyl

content of 82 percent which has been aminated so that 30.6 percent of its hydroxyl groups is converted to amine moieties). The reactor is purged with nitrogen and the mixture is heated from 140°C to 150°C for 18 to 20 hours while continuously stirring. The resulting intermediate product is a transparent light orange liquid with a viscosity of about 1040 cps at 25°C.

To the intermediate product in the reactor is added further 3.85 parts of biuret and 7.41 parts of bis(4-aminophenyl)methane. The biuret and diamine are added, as a mixture, to the reactor periodically, about every 45 minutes, in portions of about 1.5 parts by weight while continuously stirring and maintaining the temperature at 140°C to 150°C. The contents of the reactor are stirred continuously until titrometric analysis shows that the amine concentration is constant, in this case about 60 hours.

On cooling, the finished product is a stable particulate polybiuret dispersion which has a viscosity of about 3600 cps at 25°C. The particulate polymer con¬ tent is about 9.1 percent, with particle sizes ranging from 0.1 to 25 microns. SEM indicates that the particles are spherical.

Example 15 - A Particulate Polymer Com¬ position Where the Partic¬ ulate Polymer is Prepared in a Different Continuous

Phase

To a reactor is added 100 parts of a continuous phase, a polyether polyol, VORANOL™ 5287 (an ethylene oxide/propylene oxide adduct of propylene glycol, equivalent weight about 1000; sold by The Dow Chemical

Company), 0.14 part of urea, 0.15 part of hexamethylene- -1 ,6-diamine, and 2.0 parts of an aminated polyether polyol (an ethylene oxide/propylene oxide adduct of glycerine, hydroxyl equivalent weight about 1610 and primary hydroxyl content of 82 percent which has been aminated so that 30.6 percent of its hydroxyl groups is converted to amine moieties). The reactor is purged with nitrogen and the mixture is heated from 140°C to 150°C for 18 to 20 hours while continuously stirring.

10 The resulting intermediate product is a turbid gray liquid.

To the intermediate product in the reactor is added further 4.29 parts of urea and 8.28 parts of

15 hexamethylene-1 ,6-diamine. The urea and diamine are added, as a mixture, to the reactor periodically, about every 45 minutes, in portions of about 1.33 parts by weight while continuously stirring and maintaining the temperature at 140°C to 150°C. The contents of the

20 reactor are stirred continuously until titrometric analysis shows that the amine concentration is constant, in this case about 21 hours. The resulting particulate polymer (polyurea) in the continuous phase is then _p c heated with a further 0.51 part urea, and stirred for about 15 hours at 140°C to 150°C.

On cooling, the finished product is a stable particulate polyurea dispersion which has a viscosity of 30 about 1170 cps at 25°C. The particulate polymer content is about 9.1 percent, with particle sizes ranging from 0.1 to 25 microns. SEM indicates that the particles are spiral fiber bundles having an aspect ratio greater than 5.

Example 16 - Example of Redispersion of a Particulate Polymer in a Polyester Polyol

To 100 parts of the particulate polyurea dis¬ persion obtained in Example 1 is added 225 parts of a mixture consisting of 70 volume percent isooctane and 30 volume percent toluene. The resulting dispersion is stirred and then filtered using a suitable fine porosity glass filter and the particulate polyurea isolated.

The particulate polyurea is washed several times with the solvent mixture to remove all traces of the continuous and then dried in a vacuum oven for 16 hours at 120°C/<1 mm Hg to give a white powder.

A new polyurea dispersion is prepared by dis¬ persing 10 parts of the isolated white powder in 90 parts of a continuous phase, Formrez 11-56 (a polyester polyol made by Witco Corporation; the reaction product of diethylene glycol and adipic acid, equivalent weight about 1000).

The resulting stable polyurea dispersion pre- pared in this manner has a particulate polymer content of 10 percent by weight, viscosity of 30,000 cps at 25°C and an equivalent weight of about 1100 g/eq OH.

Example 17 - Preparation of a Particu¬ late Polymer from Thiourea and Hexamethylene-1,6-di- amine

To a reactor is added 100 parts of a continuous phase, a polyether polyol, VORANOL™ 4702 (an ethylene oxide/propylene oxide adduct of glycerine, equivalent

weight about 1610 and primary hydroxyl content of 82 percent; sold by The Dow Chemical Company), 0.19 part of thiourea, 0.13 part of hexamethylene-1 ,6-diamine, and 2.0 parts of an aminated polyether polyol (an ethylene oxide/propylene oxide adduct of glycerine, hydroxyl equivalent weight about 1610 and primary hydroxyl con¬ tent of 82 percent which has been aminated so that 30.6 percent of its hydroxyl groups is converted to amine moieties). The reactor is purged with nitrogen and the mixture is heated from 140°C to 150°C for 18 to 20 hours while continuously stirring. The resulting intermediate product (stabilizer) is a transparent, light orange liquid with a viscosity of about 840 cps at 25°C.

To the intermediate product in the reactor is added further 4.81 parts of thiourea and 7.38 parts of hexamethylene-1,6-diamine. The urea and diamine, as a mixture, are added to the reactor periodically, about every 45 minutes, in portions of about 2.0 parts by weight while continuously stirring and maintaining the temperature at 140°C to 150°C. The contents of the reactor are stirred constantly, until titrometric analysis shows that the amine concentration is constant, in this case about 19 hours.

On cooling, the finished product is a transpar¬ ent yellow liquid which has a viscosity of about 3700 cps at 25°C. The polymer content is 9.1 percent. On heating to above about 65°C, the product is an opaque white liquid, a dispersion of poly(hexamethylene thio¬ urea), which has a viscosity of about 150 cps at 75°C.

Example 18 - Example of a Particulate Poly¬ mer Composition Containing 5 Percent by Weight Particulate

Polymer Prepared in situ from Urea and Bis(4-aminophenyl) methane

To a reactor is added 100 parts of a continuous phase, a polyether polyol, VORANOL™ 4702 (an ethylene oxide/propylene oxide adduct of glycerine, equivalent weight about 1610 and primary hydroxyl content of 82 percent; sold by The Dow Chemical Company), 0.07 part of urea, 0.10 part of bis(4-aminophenyl)methane, and 0.91 part of an aminated polyether polyol (an ethylene

10 oxide/propylene oxide adduct of glycerine, hydroxyl equivalent weight about 1610 and primary hydroxyl con¬ tent of 82 percent which has been aminated so that 30.6 percent of its hydroxyl groups is converted to amine -.j- moieties). The reactor is purged with nitrogen and the mixture is heated from 140°C to 150°C for 4 to 8 hours while continuously stirring. The resulting intermediate product is a transparent, light orange liquid.

0 To the intermediate product in the reactor is added further 1.33 parts of urea and 4.42 parts of bis- (4-aminophenyl)methane. The urea and diamine are added to the reactor periodically, about every 30 minutes, in portions of about 0.7 part while continuously stirring 5 and maintaining the temperature at 140°C to 150°C. The contents of the reactor are stirred continuously for about 18 hours.

0 On cooling, the finished product is a stable particulate polyurea dispersion which has a viscosity of about 2000 cps at 25°C. The particulate polymer content is about 4.8 percent. The particulate polymer particles are spheres with diameters ranging from 0.1 to 15 microns.

Example 19 - Preparation of a Particulate Polymer Composition Where the Particulate Polymer is Pre¬ pared from Urea and Hexameth- ylene-1,6-diamine in the Pres¬ ence of a Stabilizer compound, Jeffamine™ M-2005

To a reactor is added 100 parts of a continuous phase, a polyether polyol, VORANOL" 4702 (an ethylene oxide/propylene oxide adduct of glycerine, equivalent

10 weight about 1610 and primary hydroxyl content of 82.0 percent; sold by The Dow Chemical Company), 0.15 part of urea, 0.16 part of hexamethylene-1 ,6-diamine, and 0.50 part of Jeffamine™ M-2005 (an ethylene oxide/ propylene

-.,- oxide adduct of 2-methoxyethanol, molecular weight about 2000, which has been aminated so that its hydroxyl groups are converted to amine moieties, sold by Texaco Chemical Company). The reactor is purged with nitrogen and the mixture is heated from 140°C to 150°C for 18 to 0 26 hours while continuously stirring. The resulting intermediate product (stabilizer) is a turbid gray liquid with a viscosity of 970 cps.

To the intermediate product in the reactor is added further 4.29 parts of urea and 8.22 parts of hexa- methylene-1 ,6-diamine. The urea and diamine are added to the reactor periodically, about every 45 minutes, in portions of about 1.33 parts while continuov.sly stirring 0 and maintaining the temperature at 140°C to 150°C. The contents of the reactor are stirred continuously until titrometric analysis shows that the amine concentration is constant, in this case about 33 hours. The resulting particulate polymer (polyurea) in the continuous phase is then treated with a further 0.43 part of urea, and

stirred for about 23 hours at 140°C to 150°C before purging the headspace with nitrogen to remove any non- -polymerized starting materials and/or volatile products.

On cooling, the finished product is a stable particulate polyurea dispersion which has a viscosity of about 2400 cps at 25°C. The particulate polymer content is 9.1 percent, with particle sizes ranging from 0.1 to 25 microns. SEM indicates that the particles are spiral fiber bundles, having aspect ratios greater than 5.

Example 20 Preparation of a Particulate Polymer

Composition Where the Particulate Polymer is Prepared from Urea and 1,6-Hexanediamine

Without a Stabilizer compound

To a silanized glass reactor is added 150 parts of a continuous phase, a polyether polyol, Voranol™ 4702 (an ethylene oxide/propylene oxide adduct of glycerine, equivalent weight about 16010 and primary hydroxyl content of 82 percent; sold by The Dow Chemical Company) . The reactor is purged with nitrogen and the ixtue is heated to about 150°C. Urea (6.37 parts) and 1,6-hexanediamine (12.40 parts) are ground together and well mixed in a jar in a nitrogen environment. Increments (-2.7 parts) of the urea/1,6-hexanediamine mixture are added to the reactor over a total time of 5 hours. The contents of the reactor are stirred until titrometric analysis shows no change in amine concentration.

The resulting particulate polymer (polyurea) in the continuous phase is then treated with a further 1.15 parts of urea, and stirred for about 16 hours at about

150°C before purging the headspace of the reactor with nitrogen to remove any non-polymerized staring material and/or volatile products.

After purging, the particulate polymer and continuous phase are treated with 0.7 parts of benzol chloride, to give a finished product. On cooling, the finished product is a stable particulate polyurea dispersion which has a viscosity of about 2500 cps at 25°C, particulate polymer content of about 9.5 percent by weight, with particle size ranges of 1 to 30 microns. SEM indicates that the particulates are spiral fiber bundles, having aspect ratios greater than 5.

Example 21 - A Particulate Polymer Compo- sition Wherein the Particulate

Polymer is Prepared from 1,3- -Diethylurea and Hexamethyl- ene-1,6-diamine

To a reactor is added 100 parts of a continuous phase, a polyether polyol, VORANOL™ 4702 (an ethylene oxide/propylene oxide adduct of glycerine, equivalent weight about 1610 and primary hydroxyl content of 82 percent; sold by The Dow Chemical Company), 0.16 part of urea, 0.16 part of hexamethylene-1 ,6-diamine, and 2.0 parts of an aminated polyether polyol (an ethylene oxide/propylene oxide adduct of glycerine, hydroxyl equivalent weight about 1610 and primary hydroxyl content of 82 percent which has been aminated so that 30.6 percent of its hydroxyl groups is converted to amine moieties). The reactor is purged with nitrogen and the mixture is heated from 140°C to 150°C for 18 to 26 hours while continuously stirring. The resulting intermediate product is a turbid gray liquid.

To the intermediate product in the reactor is added further 8.21 parts of 1 ,3-diethylurea and 8.17 parts of hexamethylene-1,6-diamine. The urea and diamine are added to the reactor periodically, about every 45 minutes, in portions of about 1.8 parts while continuously stirring and maintaining the temperature at 140°C to 150°C. The contents of the reactor are stirred continuously until titrometric analysis shows that the amine concentration is constant, in this case about 33 hours. The resulting particulate polymer (polyurea) in the continuous phase is then treated with a further 1.23 parts of 1,3-diethylurea, and stirred for about 23 hours at 140°C to 150°C before purging the headspace with nitrogen to remove any non-polymerized starting materials and/or volatile products.

On cooling, the finished product is a stable particulate polyurea dispersion which has a viscosity of about 2900 cps at 25°C The particulate polymer content is about 9.1 percent, with particle sizes ranging from 0.1 to 25 microns.

Example 22 Use of a Particulate Polymer Composition to Prepare Flexible Polyurethane Foams

A series of polyurea dispersions based on urea, 1,6-hexanediamine, and an aminated polyether polyol (an ethylene oxide/propylene oxide adduct of glycerine, hydroxyl equivalent weight about 1610 and primary hydroxyl content of 82 percent which has been partially aminated so that 30.6 percent of its hydroxyl groups are converted to amine moieties) are prepared in a continuous phase, a polyether polyol, Voranol™ 4702 (an ethylene oxide/propylene oxide adduct of glycerine, equivalent weight about 1610 and primary hydroxyl

content of 82 percent; sold by The Dow Chemical Company) using a procedure similar to that in Example 1. The samples are combined and blended to a single batch of polyurea dispersion which has a viscosity of about 2280 cps at 25°C, a particulate polymer content of about 10 percent by weight, with particle size ranges of 1 to 10 microns. SEM indicates that the particles are spiral fiber bundles, having an aspect ratio of about 10.

Flexible foams are prepared in a box molder using the following formulation (5 weight percent particulate polyemr in the polyol):

50 parts V-4703C ¹

50 parts polyurea dispersion of Example 22

3.5 parts water

1.5 parts diethanolamine

0.45 parts DABC0 33-LV ²

0.15 parts NIAX A-1 ³ 1.2 parts DC-5043 ⁴

46.2 parts Voranate T-80 ⁵ NC0/0H = 1.00 TDI/polyol = 0.431 Foam Weight = 690 g

¹ A 5000 molecular weight ethylene oxide (20* cap)/proplyene oxide adduct of glycerine manufactured by The Dow Chemical Company.

² Triethylenediamine catalyst manufactured by Air Products.

³ A catalyst manufactured by Union Carbide Corporation.

⁴ Surfactant sold by Dow Corning.

⁵ Toluenediisocynate manufactured by The Dow Chemical Company.

The polyol components are charged to a s.s. Beaker in the proportions described above and mixed at 1750 rpm with a pin mixer for 20 seconds to insure homogeneity. Voranate T-80 is added and mixed at 3300 rpm for 2.5 seconds. The material is then charged to a 15" x 15" x 4.5" aluminum box mold treated with Delift-14 mold release (Cramer Chemical Company). The initial mold

10 temperature was about 60°C. Two minutes after the Voranate™ T-80 addition, the mold is charged to a 107°C oven. It is left in the oven for four minutes, then removed and demolded.

-. _£ . The foam pads are crushed by hand to open the cells. The foams are opaque, light yellow and non-tacky.

A second set of flexible foams are prepared in 0 a box molder using the following formulation (10 wt percent particulate polymer in the polyol):

100 parts polyurea dispersion of Example 22 3.5 parts water 5 1.5 parts diethanolamine 0.50 parts DABC0 33-LV 0.17 parts NIAX A-1 1.5 parts DC-5043 46.2 parts Voranate T-80 0

Foams are prepared by the same procedure described above. The foam pads are crushed by hand to open the cells. The foams are opaque, light yellow and non-tacky.

Example 23 Physical Properties of

Polyurethane Flexible Foams

The physical properties of several polyurethane flexible foams of this invention are analyzed. Results ft are tabulated in Table IV. 5

The load bearing properties are increased significantly (improved) by using the particulate particules of this invention at the 5 percent loading

10 level. Modulus approaches 3.0 at 10 percent loading using the particulate particules of this invention. The optimum comfort level in automotive seatings is obtained at a modulus of 3.0. Tear properties are increased significantly (improved) by using the particulate

15 particules of this invention at 5 percent loading level. Both the compression set and the humid age compression set decrease (improve) by the use of the particulate particules of this invention at both the 5 and 10

P ₀ percent loading level.

The improvements attained by using particulate particles of this invention are a consequence of its novel chemical composition and its aspect ratio (about 25 10).

30

TABLE IV PHYSICAL PROPERTIES OF POLYURETHANE FLEXIBLE FOAMS

% Solids

Pad wt (g) Density (kglm^) LOAD BEARING 25% IFD 50% IFD 65% IFD Hysteresis (%) Modulus

TENSILE/TEAR Tear (N/m) Tensile (kPa) Elongation (%) COMPRESSION SET CSd 50% (%) HACSd 50% (%) IFD Identification force deflection

CSd 50% Compression set at 50% compression HACSd 50% Humid Age Compression set at 50% compression