CA1120671A - Homogeneous, isotropic, three-dimensional microporous polymer structure and method of making same - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A method of preparing a relatively homogeneous, iso-tropic, three-dimensional microporous polymer structure com-prising heating a mixture of a synthetic thermoplastic polymer selected from the group consisting of olefinic polymers, con-densation polymers, oxidation polymers, and blends thereof, and a compatible liquid to a temperature and for a time suffi-cient to form a homogeneous solution. me solution is allowed to assume a desired shape, it is cooled in the desired shape at a rate and to a temperature sufficient to initiate thermo-dynamic, non-equilibrium liquid-liquid phase separation, cooling is continued to form a solid and at least a substantial portion of the liquid is removed from the resulting solid to form the microporous polymer structure.

Description

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m is invention relates to porous polymer structures and a method of preparing the same. More particularly, this invention relates to microporous polymer structures that may be readily prepared and are characterized by relatively homo-geneous, three-dimensional, cellular microstructures and to a unique, facile process for preparing microporous polymer structures.
Several widely differing techniques have been pre-viously developed for preparing microporous polymer struc-tures. Such techniques range from what is termed, in the art,classical phase inversion, to nuclear bombardment, to incor-poration of microporous solid particles in a substrate which are subsequently leached out, to sintering microporous particles together in some fashion. Prior efforts in the field have entailed still other techniques as well as innummerable variations of what may be considered as the classical or basic techniques.
The interest in microporous polymer products has been engendered by the numerous potential applications for materials of this type. These potential applications are well knwon and range from ink pads, or the like, to leather-like breathable sheets, to filter media. Yet, with all of the potential applications, the commercial usage has been rela-tively modest. And, the techniques being commercially uti-lized have various limitations which do not allow the versa-tility required to expand the applications to reach the po-tential market for microporous products.
As mentioned, some commercially available micro-porous polymer products are made by a nuclear bombardment technique. Such a technique is capable of achieving a rather narrow pore size distribution, however, the pore volume must ,~ ' llZ~6 7~

be relatively low (i.e. - less than about 10% void space) to insure that the polymer will not be degraded during prepara-tion. Many polymers cannot be utilized in such a technique due to the lack of the ability of the polymer to etch. Still further, the technique requires that a relatively thin sheet or film of the polymer be used and considerable expertise must be employed in carrying out the procedure to avoid "double tracking", which results in the formation of oversized pores.
Classical phase inversion has also been commercial-ly utilized to form microporous polymers from cellulose ace-tate and certain other polymers. Classical phase inversion has been reviewed in great detail by R.E. Kesting in SYNTHETIC
POLYMERIC MEMBRANES, McGraw-Hill, 1971. In particular at page 117 of said reference it is explicitly stated that classical phase inversion involves the use of at least three components, a polymer, a solvent for said polymer and a non-solvent for said polymer.
Reference may also be made to U.S. Patent No.
3,945,926 which teaches the formation of polycarbonate resin membranes from a casting solution containing the resin, a sol-vent, and a swelling agent and/or a nonsolvent. It is stated at lines 42-47, column 15, of said patent that in the complete absence of a swelling agent phase inversion usually does not occur and that with low concentrations of swelling agents, - structures possessing closed cells are encountered.
From the foregoing discussion it is quite apparent that classical phase inversion requires the use of a solvent for the system at room temperature so that many other useful polymers cannot be substituted for the polymers such as cellu-lose acetate. Also from the process standpoint, the classical '71 phase inversion process will generally be restricted to the formation of films due to the large amount of solvent used in the preparation of solutions which must be subsequently ex-tracted. It is also apparent that classical phase inversion requires a relatively high degree of process control to obtain structures of desired configuration. Thus the relative con-centrations of solvent, nonsolvent, and swelling agent must be critically controlled, as discussed in column 14-16 of U.S. Patent No. 3,945,926. Conversely, to alter the number, size, and homogeneity of the resultant structure, one must modify the aforementioned parameters by trial-and-error.
Other commercially available microporous polymers are made by sintering microporous particles of polymers rang-ing from high density polyethylene to polyvinylidene fluoride.
However, it is difficult with such a technique to obtain a product with the narrow pore size distribution required for many applications.
A still further general technique which has been the subject of considerable prior effort involves heating a polymer with various liquids to form a dispersion or solution and thereafter cooling, followed by removal of the liquid with a solvent or the like. This type of process is disclosed in the following United States patents which are only repre-sentative and not cumulative: 3,607,793, 3,378,507, 3,310,505;
3,748,287, 3,536,796, 3,308,073, and 3,812,224. It is not believed that the foregoing technique has been utilized com-mercially to any significant extent, if at all, probably due to the lack of economic feasibility of the particular pro-cesses which have previously been developed. Also, the prior processes do not allow the preparation of microporous polymers which combine relatively homogeneous microcellular ~l~Z~36'7~

structures with the pore size and pore size distributions which are typically desired.
With respect to the microporous polymers obtained by prior art techniques, no process known heretofore has been capable of yielding isotropic olefinic or oxidation polymers which have the major portion of pore sizes in the range of about 0.1 to about 5 microns while having a relatively narrow pore size distribution, thus exhibiting a high degree of pore size uniformity throughout a sample thereof. Some prior art olefinic or oxidation polymers have had pore sizes in the foregoing range, but without a relatively narrow pore size distribution, thus making such materials without significant value in application areas, such as filtration, which require a high degree of selectivity. Furthermore, prior microporous olefinic or oxidation polymers which may be con-sidered to have relatively narrow pore size distributions have had absolute pore sizes which are outside the aforementioned range, usually having substantially smaller pore sizes, for use in application areas such as ultra-filtration. Finally, some prior art olefinic polymers have had pore sizes in the foregoing range and what may be considered to be relatively narrow pore size distributions. However, such materials have been made by use of techniques, such as stretching which impart a high degree of orientation to the resultant anisotro-pic material, rendering it undesirable for many application areas. There thus has existed a need for microporous olefinic and oxidation polymers having a pore size in a range of from about 0.1 to about 5 microns and characterized as having a relatively narrow isotropic pore size distribution.
Also,a major drawback of many microporous polymers available heretofore has been the low flow rate of such poly-6,1 mers when used in structures such as microfiltration membranes.
One of the major reasons for such low flow rates is the typi-cally low void volume of many such polymers. Thus, perhaps 20 percent of the polymer structure, or less, may be "void"
volume through which a filtrate may flow, the remaining 80 percent of the structure being the polymer resin which forms the microporous structure. Thus, there has also existed a need for microporous polymers having a high degree of void volume, especially with respect to olefinic polymers.
~he Japanese patent disclosure number 105293/75 published on August 19, 1975,discloses a highly advantageous method for converting a particular type of liquid amine anti-static agent to a material which behaves as a solid. The ad-vantages in processing which result are real and significant.
It would be similarly beneficial to be able to convert other useful functional liquids such as flame retardants and the like to materials which behave as solids.
It is accordingly an object of the present invention to provide microporous polymer products characterized by relative homogeneity and narrow pore size distributions.
Another object is to provide a facile process which allows the economic production of microporous polymers.
A still further object lies in the provision of a process for making microporous polymer products, w~ich has applicability to a wide number of useful thermoplastic poly-mers. A related and more specific object is to provide such a process which is capable of readily forming microporous po-lymers from any synthetic thermoplastic polymer including polyolefins, condensation polymers and oxidation polymers.
Yet another object of this invention is to provide microporous polymers in structures ranging from thin films to ~l'Z~6'7~

relatively thick blocks~ A related object is to provide the ability to form microporous polymers in intricate shapes.
A further object is to provide the conversion of functional liquids to materials which possess the character-istics of a solid.
In accordance with the invention there is provided a method of preparing a relatively homogeneous, isotropic, three-dimensional microporous polymer structure comprising heating a mixture of a synthetic thermoplastic polymer selected from the group consisting of olefinic polymers, con-densation polymers, oxidation polymers, and blends thereof, and a compatible liquid to a temperature and for a time suf-ficient to form a homogeneous solution, allowing said solu-tion to assume a desired shape, cooling said solution in said desired shape at a rate and to a temperature sufficient to initiate thermodynamic, non-equilibrium liquid-liquid phase separation, continuing cooling to form a solid and removing at least a substantial portion of the liquid from the result-ing solid to form the microporous polymer structure.

Other objects and advantages of the present inven-tion will become apparent from the following discussion, and from the drawings, in which:
Figure 1 is a graph of temperature vs. concentration for a hypothetical polymer-liquid system, setting forth the binodial and spinodal curves, and illustrating the concentra-tion necessary to achieve the microporous polymers and to practice the process of the present invention;
Figure lA is a graph of temperature vs. concentra-tion similar to that of Figure 1, but also including the freezing point depression phase line;

Figure 2 is a photomicrograph, at 55X amplification, showing the macrostructure of a polypropylene microporous polymer of the present invention with about a 75 per cent void volume;
Figures 3 through 5 are photomicrographs of the microporous polypropylene structure of Figure 2 at, respective-ly, 550X, 2200X and 5500X amplification, and illustrate a homogeneous cellular structure;
Figures 6 through 10 are photomicrographs at, res-pectively, 1325X, 1550X, 1620X, 1450X and 1250X amplification of additional microporous polypropylene structures and show the modifications in the structure as the void space is reduced from 90%, to 70%, to 60%, to 40%, and to 20%, res-pectively;
Figures 11 through 13 are photomicrographs at, res--6a-'l.i'~06'7~

pectively, 2000X, 2050X and 1950X amplification of still fur-ther microporous polypropylene structures of the present in-vention and illustrate the decreasing cell size as the poly-propylene content is increased from the 10% by weight level in Figure 11, to 20%, and to 30%, in Figures 12 and 13, res-pectively;
Figures 14 through 17 are photomicrographs at, res-pectively, 250X, 2500X, 2500X and 2475X amplification of microporous low density polyethylene structures of the present invention, Figures 14 and 15 showing the macro- and micro-structure of a microporous polymer containing 20% by weight polyethylene and Figures 16 and 17 showing the microstructure with 40% and 70% polyethylene respectively, Figures 18 and 19 are photomicrographs at, respect-ively, 2100X and 2000X amplification of microporous high den-sity polyethylene structures of the present invention and il-lustrate the structures at 30% and 70% by weight polyethylene, respectively.
Figures 20 and 21 are photomicrographs, at, respect-ively, 2550X and 2575X amplification of microporous SBR poly-mers of the present invention and show a homogeneous cellular structure, Figure 22 is a photomicrograph at 2400X amplifica-tion of a microporous methylpentene polymer, Figures 23 and 24 are photomicrographs at, respect-ively, 255X and 2550X amplification of a microporous ethylene-acrylic acid copolymer, ; Figure 25 is a photomicrograph at 2500X amplifica-tion of a microporous polymer formed from a polyphenylene oxide-polystyrene blend, Figure 26 is a photomicrograph at 2050X amplifica-)6'71 tion and illustrates a polystyrene microporous polymer, Figure 27 is a photomicrograph at 2000X amplifica-tion and showing a polyvinylchloride microporous polymer, Figures 28 and 29 are photomicrographs at 2000X am-plification of low density polyethylene microporous polymers and showing the partial masking of the basic structure by the "foliage" mode structure' Figures 30 to 33 are mercury intrusion curves of microporous polypropylene structures of the present invention and illustrating the narrow pore diameter distribution which is characteristic of the polymers of the instant invention Figures 34 to 40 are mercury intrusion curves of commercial microporous products including "Celgard"* poly-propylene (Fig. 34), "Amerace* A20" and "Amerace*A30" poly-vinyl chloride (Figs. 35 and 36 respectively),- "Porex" poly-propylene (Fig. 37), "Millipore* BDWP 29300" cellulose ace-tate (Fig. 38), "Gelman TCM-200" cellulose triacetate and "Gelman Acropor WA" acrylonitrile-polyvinyl chloride copoly-mer (Figs. 39 and 40 respectively);
Figures 41 through 43 are mercury intrusion curves of microporous structures made in accordance with U.S.
3,378,507, using polyethylene (Figs. 41 and 42) and poly-propylene (Fig. 43), Figure 44 is a mercury intrusion curve of a poly-ethylene microporous material made in accordance with U.S.
3,310,505, Figures 4S to 46 are photomicrographs of a porous polyethylene product prepared by duplicating Example 2 of - 3,378,507 using an injection molding technique, Fig. 45 (240X amplification) showing the macrostructure and Fig. 46 * Trade Mark l~Z~67~

(2400X amplification) showing the microstructure, Figures 47 to 48 are photomicrographs of a porous polyethylene product prepared by duplicating Example 2 of U.S. 3,378,507 using a compression molding technique, Fig.
47 (195X amplification) showing the macrostructure and Fig.
48 (2000X amplification) showing the microstructure;
Figures 49 to 50 are photomicrographs of a porous polypropylene product prepared by duplicating Example 2 of U.S. 3,378,507 using an injection molding technique, Fig. 49 (195X amplification) showing the macrostructure and Fig. 50 (2000X amplification) showing the microstructure, Figures 51 to 52 are photomicrographs of a porous polypropylene product prepared by duplicating Example 2 of U.S. 3,378,507 using a compression molding technique, Fig. 51 (206X amplification) showing the macrostructure and Fig. 52 (2000X amplification) showing the microstructure, and Figures 53 to 54 are photomicrographs of a porous polyethylene product prepared by duplicating Example 2 of U.S. 3,310,505, Fig. 53 (205 amplification) showing the macro-structure and Fig. 54 (200X amplification) showing the micro-structure:
Figure 55 shows a melt curve and a crystallization curve for a polypropylene and quinoline polymer/liquid system, Figure 56 shows a melt curve and several crystalli-zation curves for a polypropylene and N,N bis(2-hydroxyethyl) tallow-amine polymerJliquid system, Figure 57 shows a melt curve and a crystallization curve for a polypropylene and dioctyl phthalate polymer/liquid system, demonstrating a system which is not within the scope of the present invention, Figure 58 shows the phase diagram for a low molecu-lar weight polyethylene and diphenyl ether polymer/liquid 06'7~

system, determined at cooling and heating rates of 1C/minute;
Figure 59 shows several melt and crystallization cur-ves for a low molecular weight polyethylene and diphenyl ether polymer/liquid system' Figure 60 shows a glass transition curve for a low molecular weight polystyrene and l-dodecanol polymer/liquid system, Figure 61 is a photomicrograph at 5000X amplifica-tion of a 70 per cent void microporous cellular structure of the present invention, made from polymethylmethacrylate, Figure 62 shows melt and crystallization curves for a Nylon 11 and tetramethylene sulfone polymer/liquid system;
Figure 63 is a photomicrograph at 2000X amplifica-tion of a 70 per cent void microporous cellular structure of the present invention, made from ~ylon 11, Figure 64 is a photomicrograph at 2000X amplifica-tion of a 70 per cent void microporous cellular structure of the present invention, made from polycarbonate, Figure 65 is a photomicrograph at 2000X amplifica-tion of a 70 per cent void microporous cellular structure of the present invention, made from polyphenylene oxide:
Figures 66 and 67 are photomicrographs at 2000X am-plification of a 60 per cent void and a 75 per cent void, res-pectively, microporous non-cellular structure of the present invention, made from polypropylene;
Figures 68 and 69 are, respectively, mercury intru-sion curves of a 60 per cent void and a 75 per cent void non-cellular microporous polypropylene structure within the scope of the present invention, Figure 70 is a graphical representation of the unique microporous cellular structures of the present invention as compared to certain prior art compositions.

)6'71 While the invention is susceptible of various modifi-cations and alternative forms, there will be herein described in detail the preferred embodiments. It is to be understood, however, that it is not intended to limit the invention to the specific forms disclosed. On the contrary, it is intended to cover all modifications and alternative forms falling with-in the spirit and scope of the invention as expressed in the appended claims.
It has now been discovered that any synthetic thermoplastic polymer may be rendered microporous by first heating said polymer and a compatible liquid, discussed hereinbelow, to a temperature and for a time sufficient to form a homogeneous solution. The so formed solution is then allow-ed to assume a desired shape and subsequently cooled in said shape at a rate and to a temperature sufficient so that thermodynamic non-equilibrium liquid-liquid phase separation is initiated. As the solution is cooled in the desired shape, no mixing or other shear force is applied while the solution is undergoing the cooling. The cooling is continued so that a solid results. me solid needs only to attain sufficient mechanical integrity to allow it to be handled, without caus-ing physical degradation. Finally, at least a substantial portion of the compatible liquid is removed from the resulting solid to form the desired microporous polymer, Certain novel microporous olefinic and oxidation polymers of the present invention are characterized by a narrow pore size distribution, as determined by mercury intru-sion porosimetry. The narrow pore size distribution may be analytically expressed in terms of a sharpness function "S"
which is explained in detail hereinbelow. The "S" values of the olefinic and oxidation polymer of the present invention ~lZ(~6;71 range from about 1 to about 10. Also, said polymers of the present invention are characterized by average pore sizes which range from about 0.10 to about 5 microns about 0.2 to about 1 micron being preferred. Furthermore~ such microporous products are substantially isotropic, and thus have essential-ly the same cross-sectional configuration when analyzed along any spatial plane.
In another aspect of the present invention the method of preparing microporous polymers is performed so that a mixture comprising a synthetic thermoplastic polymer, es-pecially a polyolefin, an ethylene-acrylic acid copolymer, a polyphenylene oxide-polystyrene blend, or a blend of one or more of the foregoing polymers, and a compatible liquid is heated to a temperature and for a time sufficient to form a homogeneous solution. The solution is then cooled, thus forming at substantially the same time a plurality of liquid droplets of substantially the same size. The cooling is then continued to solidify the polymer and at least a substantial portion of the liquid is removed from the resulting solid to form the desired cellular polymer structure.
The foregoing method will result in microporous polymer products characterized by a cellular, three-dimension-al, void microstructure, i.e. - a series of enclosed cells having substantially spherical shapes and pores or passage-ways interconnecting adjacent cells. ~he basic structure is relatively homogeneous with the cells being uniformly spaced throughout the three dimensions, and the interconnecting pores have diameters which are relatively narrow in size distribu-tion as measured by mercury intrusion. For ease of reference, microporous polymers having such a structure will be referred to as "cellular".

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A related aspect of this invention provides novel microporous polymer products which behave as solids and con-tain relatively large amounts of functionally useful liquids such as, for example, polymer additives including flame re-tardants and the like. In this fashion, useful liquids may obtain the processing advantages of a solid material which may be used directly, as for example, in a master batch.
Such products may be formed directly by using a functional liquid as the compatible liquid and not carrying out the re-moval of the compatible liquid or indirectly by either re-loading the microporous polymer after the removal of the com-patible liquid or displacing the compatible liquid before removal to incorporate the functional liquid~
Broadly, the practice of the process of the instant invention involves heating the desired polymer with an appro-priate compatible liquid to form a homogeneous solution, cool-ing said solution in an appropriate manner to form a solid material and subsequently extracting the liquid to form a microporous material. The considerations involved in prac-ticing the instant invention will be described in detail here-inbelow.
As indicated, the present invention surprisingly affords a technique for rendering any synthetic thermoplastic polymer microporous. ~hus, the process of the present inven-tion applies to olefinic polymers, condensations polymers, and oxidation poIymers.
Exemplary of the useful non-acrylic polyolefins are low density polyethylene, high density polyethylene, poly-propylene, polystyrene, polyvinylchloride, acrylonitrile-butadiene-styrene terpolymers, styrene-acrylonitrile copoly-mers, styrene butadiene copolymers, poly (4-methyl-pentene-1), '7~

polybutylene, polyvinylidene chloride, polyvinyl butyral, chlorinated polyethylene, ethylene-vinyl acetate copolymers, polyvinyl acetate, and polyvinyl alcohol.
Useful acrylic polyolefins include polymethyl-methacrylate, polymethyl-acrylate, ethylene-acrylic acid co-polymers, and ethylene-acrylic acid metal salt copolymers.
Polyphenylene oxide is representative of the oxida-tion polymers which may be utilized. lhe useful condensa-tion polymers include polyethylene terephthalate, polybutylene terephthalate, ~ylon 6, ~ylon 11, ~ylon 13, ~ylon 66, poly-carbonates and polysulfone.
Thus, to practice the present invention one need only first choose the synthetic thermoplastic polymer which is to be rendered microporous. Having selected the polymer, the next procedure is the selection of the appropriate compatible liquid and the relative amounts of polymer and liquid to be utilized. Of course blends of one or more polymers may be utilized in the practice of the present invention. Function-ally, the polymer and liquid are heated with stirring up to the temperature required to form a clear, homogeneous solu-tion. If a solution cannot be formed at any liquid concen-tration, then the liquid is inappropriate and cannot be utilized with that particular polymer.
Because of the selectivity, absolute predictability for predetermining the operability of a particular liquid with a particular polymer is not possible. However, some use-ful general guidelines can be set forth. Thus when the poly-mer involved is non-polar, non-polar liquids with similar solubility parameters at the solution temperature are more likely to be useful~ When such parameters are not available, one may refer to the more readily available room temperature solubility parameters, for general guidance~ Similarly, with i'7~

polar polymers, polar organic liquids with similar solubility parameters should be initially examined. Also, the relative polarity or non-polarity of the liquid should be matched with the relative polarity or non-polarity of the polymer. In ad-dition, with hydrophobic polymers, useful liquids will typic-ally have little or no water solubility. On the other hand, polymers which tend to be hydrophilic will generally require a liquid having some water solubility.
With respect to appropriate liquids, particular species of various types of organic compounds have been found useful, including aliphatic and aromatic acids, aliphatic, aromatic and cyclic alcohols, aldehydes, primary and secondary amines, aromatic and ethoxylated amines, diamines, amides, esters and diesters, ethers, ketones and various hydrocarbons and heterocycles. It should, however, be noted that the con-cept is quite selective. Thus, for example, not all saturated aliphatic acids will be useful, and, further, not all liquids useful for high density polyethylene will necessarily be use-ful for, as an example, polystyrene.

As will be appreciated, the useful proportions of polymer and liquid for any particular system can readily be developed from an evaluation of the parameters which will be discussed subsequently.
Where blends of one or more polymers are used, as should be understood, useful liquids must typically be oper-; able with all of the polymers included. It may however be possible for the polymer blend to have characteristics such that the liquid need not be operable with all polymers used.
As one example, where one or more polymeric constituents are present in such relatively small amounts as to not signifi-cantly affect the properties of the blend, the liquid employed )6'7~

need only be operable with the principal polymer or polymers.
Also, while most useful materials are liquids at ambient temperatures, materials which are solid at room tem-perature may be employed so long as solutions can be formed with the polymer at elevated temperatures and the material does not interfere with the formation of the microporouQ
structure. More specifically, a solid material may be used so long as phase separation occurs by liquid-liquid separa-tion rather than liquid-solid separation during the cooling step which will hereinafter be discussed. The amount of li-quid used can be, in general, varied from about 10 to about 90%.
As presently discussed any synthetic thermoplastic polymer may be employed so long as the liquid selected forms a solution with the polymer and the concentration yields a continuous polymer phase upon separation during cooling, as will be discussed in more detail hereinafter. So that one may appreciate the range of operable polymer and liquid systems, a brief summary of some of such systems may be useful.
In forming microporous polymers from polypropylene, alcohols such as 2-benzylamino-1-propanol and 3-phenyl-1-propanol; aldehydes such as salicylaldehyde; amides such as N,N-diethyl-m-toluamide; amines such as N-hexyl diethanolamine, N-behenyl diethanol amine, N-coco-diethanolamine, benzyl amine, N,N-bis-~ -hydroxyethyl cyclohexyl amine, diphenyl amine and 1,12 - diamino dodecane; esters such as methyl benzoate, benzyl benzoate, phenyl salicylate, methyl salicylate and dibutyl phthalate; and ethers such as diphenyl ether, 4-bromo-diphenyl ether and dibenzyl ether have been found use-ful. In addition, halocarbons such as 1,1,2,2-tetrabromo-ethane and hydrocarbons such as trans-stilbene and other llZ536'fl alkyl/aryl phosphites are also useful as are ketones such as methyl nonyl ketone.
In forming microporous polymers from high density polyethylene, a saturated aliphatic acid such as decanoic acid, primary saturated alcohols such as decyl alcohol, and l-dodecanol, secondary alcohols such as 2-undecanol and 6-undecanol, ethoxylated amines such as N-lauryldiethanolamine, aromatic amines such as N,N-diethylaniline, diesters such as dibutyl sebacate and dihexyl sebacate and ethers such as di-phenyl ether and benzyl ether have been found useful. Otheruseful liquids include halogenated compounds such as octa-bromodiphenyl, hexabromobenzene and hexabromocyclodecane, hydrocarbons such as l-hexadecane, diphenylmethane and naph-thalene, aromatic compounds such as acetophenonone and other organic compounds such as alkyl/aryl phosphites, and quino-line and ketones such as methylnonyl ketone.
To form microporous polymers from low density poly-ethylene, the following liquids have been found useful: satur-ated aliphatic acids including hexanoic acid, caprylic acid, decanoic acid, undecanoic acid, lauric acid, myristic acid, palmitic acid and stearic acid, unsaturated aliphatic acids including oleic acid and erucic acid, aromatic acids including benzoic acid, phenyl stearic acid, polystearic acid and xylyl behenic acid and other acids including branched car-boxylic acids of average chain lengths of 6, 9, and 11 car-bons, tall oil acids and rosin acid, primary saturated alco-hols including l-octanol, nonyl alcohol, decyl alcohol, 1-decanol, l-dodecanol, tridecyl alcohol, cetyl alcohol and l-heptadecanol, primary unsaturated alcohols including un-decylenyl alcohol and oleyl alcohol, secondary alcohols in-cluding 2-octanol, 2-undecanol, dinonyl carbinol and diun-decyl carbinol and aromatic alcohols including l-phenyl 6'7~

ethanol, l-phenyl-1-pentanol, nonyl phenol, phenyl-stearyl alcohol.and l-napthol. Other useful hydroxyl-containing compounds include polyoxyethylene ethers of oleyl alcohol and a polypropylene glycol having a number average molecular weight of about 400. Still further useful liquids include cyclic alcohols such as 4, t-butyl cyclohexanol and menthol, alkehydes including salicyl aldehyde, primary amines such as octylamine, tetradecylamine and hexadecylamine, secondary amines such as bis-(l-ethyl-3 methyl pentyl) amine and ethoxylated amines including ~-lauryl diethanolamine, ~-tallow diethanol-amine, ~-stearyl diethanolamine and N-coco diethanol-amine.
Additional useful liquids comprise aromatic amines including ~-sec-butylaniline, dodecylaniline, N,N-dimethyl-aniline, N,N-diethylaniline, ~-toluidine, N-ethyl-o-toluidine, diphenylamine and aminodiphenylmethane, diamines including ~-erucyl-1,3-propane diamine and 1,8-diamino-p-menthane, other amines including branched tetramines and cyclododecylamine, amides including cocoamide, hydrogenated tallow amide, octa-decylamide, eruciamide, ~,N-diethyl toluamide and ~-trimethylol-propane stearamide, saturated aliphatic esters including methyl caprylate, ethyl laurate, isopropyl myristate, ethyl palmitate, isopropyl palmitate, methyl stearate, isobutyl stearate and tridecyl stearate, unsaturated esters including stearyl acrylate, butyl undecylenate and butyl oleate, alkoxy esters including butoxyethyl stearate and butoxyethyl oleate, aromatic esters including vinyl phenyl stearate, isobutyl phenyl stearate, tridecyl phenyl stearate, methyl benzoate, ethyl benzoate, butyl benzoate, benzyl benzoate, phenyl laur-ate, phenyl salicylate, methyl salicylate and benzyl acetateand diesters including dimethyl phenylene distearate, diethyl )6'71 phthalate, dibutyl phthalate, di-iso-octyl phthalate, di-capryl adipate, dibutyl sebacate, dihexyl sebacate, di-iso-octyl sebacate, dicapryl sebacate and dioctyl maleate. Yet other useful liquids comprise polyethylene glycol esters in-cluding polyethylene glycol (having a number of average molecular weight of about 400), diphenylstearate, polyhydro-xylic esters including castor oil (triglyceride), glycerol monostearate, glycerol monooleate, glycerol distearate glycerol dioleate and trimethylol propane monophenylstearate, ethers including diphenyl ether and benzyl ether, halogenated com-pounds including hexachlorocyclopentadiene, octabromobiphenyl, decabromodiphenyl oxide and 4-bromodiphenyl ether, hydrocarbons including l-nonene, 2-nonene, 2-undecene, 2-heptadecene, 2-nonadecene, 3-eicosene, 9-nonadecene, diphenylmethane, tri-- phenylmethane and trans-stilbene, aliphatic ketones including

2-heptanone, methyl nonyl ketone, 6-undecanone, methylundecyl ketone, 6-tridecanone, 8-pentadecanone, ll-pentadecanone, 2-heptadecanone, 8-heptadecanone, methyl heptadecyl ketone, di-nonyl ketone and distearyl ketone, aromatic ketones including acetophenone and benzophenone and other ketones including xanthone. Still further useful liquids comprise phosphorous compounds including trixylenyl phosphate, polysiloxanes, Muget hyacinth (An Merigenaebler, Inc), Terpineol Prime No. 1 (Gi-vaudan-Delawanna, Inc), Bath Oil Fragrance No. 5864 K (In-ternational Flavor & Fragrance, Inc), Phosclere* P315C
(organophosphite), Phosclere P576 (organophosphite), styren-ated nonyl phenol, quinoline and quinalidine.
To form microporous polymer products with polystyrene, useful liquids include tris-halogenated propylphosphate, aryl/
alkyl phosphites, 1,1,2,2, tetrabromoethane, tribromoneo-* Trade Mark 06'7~

pentylalcohol, 40% Voranol* C.P. 3000 polyol and tribromoneo-pentyl alcohol 60%, tris- ~-chloroethylphosphate, tris (1,3-dichloroisopropyl) phosphate, tri-(dichloropropyl) phosphate, dichlorobenzene, and l-dodecanol.
In forming microporous polymers using polyvinyl chloride, useful liquids comprise aromatic alcohols including methoxy benzyl alcohol, 2-benzylamino-1-propanol, and other hydroxyl-containing liquids including 1,3-dichloro-2-propanol.
Still other useful liquids comprise halogenated compounds in-cluding Firemaster* T33P (tetrabromophthalic diester), andaromatic hydrocarbons including trans-stilbene.
In addition, in accordance with the present inven-tion, microporous products have been made from other polymers and copolymers and blends. mus, to form microporous products from styrene-butadiene copolymers, useful Iiquids include decyl alcohol, N-tallow diethanol amine, N-coco diethanol amine and diphenyl amine. Useful liquids for forming microporous poly-mers from ethylene-acrylic acid copolymer salts include N-tallow diethanolamine, N-coco diethanolamine, dibutyl phthalate and diphenyl ether. Microporous polymer products using high impact polystyrene can be formed by employing as liquids, hexa-bromobiphenyl and alkyl/aryl phosphites. With "Noryl"* poly-phenylene oxide-polystyrene blends (General Electric Company), microporous polymers can be made utilizing N-coco diethanol amine, N-tallow diethanol-amine, diphenylamine, dibutyl phtha-late and hexabromophenol. Microporous polymers from blends of low density polyethylene and chlorinated polyethylene can be made by utilizing l-dodecanol, diphenyl ether and N-tallow di-ethanolamine. Utilizing l-dodecanol as the liquid, microporous polymer products can be made from the following blends: poly-* Trade Mark llZt)6'7~

propylene-chlorinated polyethylene, high density polyethylene-chlorinated polyethylene, high density polyethylene-polyvinyl chloride and high density polyethylene and acrylonitrile-butadiene-styrene (ABS) terpolymers. To form microporous products from polymethyl-methacrylate, 1-4,butanediol and lauric acid have been found to be useful. Microporous Nylon 11 may be made utilizing ethylene carbonate, 1,2-propylene carbonate, or tetramethylene sulfone. Also, menthol may be utilized to form microporous products from polycarbonate.
The determination of the amount of the liquid used is obtained by reference to the binodial and spinodial curves for the system, illustrative curves being set forth in Fig. 1.
As shown therein, Tm represents the maximum temperature of the binodial curve (i.e. - the maximum temperature of the system at which binodial decomposition will take place), TUcs represents the upper critical solution temperature (i.e. - the maximum temperature at which spinodal decomposition will take place), ~m represents the polymer concentration at Tm~ ~c denotes the critical concentration and ~x represents the polymer concentration of the system needed to obtain the unique microporous polymer structures of the present inven-tion. Theoretically, ~m and ~c should be virtually identical;
however, as is known, due to molecular weight distributions of commercially available polymers, ~c may be about 5% by weight or so greater than the value of ~m To form the unique microporous polymers of the present invention, the poly-mer concentration utilized for a particular system ~x' must be greater than ~c' If the polymer concentration is less than ~c~ the phase separation which will occur as the system is cooled will constitute a continuous liquid phase with a dis-continuous polymer phase. On the other hand, utilizing the 6'71 proper polymer concentration will insure that the continuous phase, which will be formed upon cooling to the phase sepa-ration temperature, will be the polymer phase, as is required to obtain the unique microcellular structures of the present invention. Likewise, as will ke apparent, the formation of a continuous polymer phase upon phase separation requires that a solution be initially formed. When the process of the pre-sent invention is not followed and a dispersion is initially formed, the resulting microporous product is similar to that achieved by sintering together polymer particles.
Accordingly, as will be appreciated, the applicable polymer concentration or amount of liquid which may be uti-lized, will vary with each system. Suitable phase diagram curves for several systems have already been developed. How-ever, if an appropriate curve is not available, this can be readily developed by known techniques. For example, a suit-able technique is set forth in Smolders, van Aartsen and Steenbergen, Kolloid - Z. u. Z. Polymere, 243, 14 (1971).
A more general graph of temperature vs. concentra-tion for a hypothetical polymer-liquid system is given by Fig. lA. me portion of the curve from ~ to ~ represents thermodynamic equilibrium liquid - liquid phase separation.
The portion of the curve from ~ to ~ represents equilibrium liquid-solid phase separation, which will be recognized as the normal freezing point depression curve of a hypothetical liquid-polymer system. The upper shaded area represents an upper liquid~liquid immiscibility which may be present in some systems. The dotted line represents the lowering of crystal-lization temperature as a consequence of cooling at a rate sufficient to achieve thermodynamic non-equilibrium liquid-liquid phase separation. me flat portion of the crystalliza-t6'71 tion vs. composition curve defines a useable composition range which is a function of the cooling rate employed, as will be discussed in more detail.
Thus, for any given cooling rate, one may plot the crystallization temperature vs. percentage resin or compatible liquid and in such a manner determine the liquid/polymer con-centration ranges which will yield the desirable microporous structures at the given cooling rate. For crystalline poly-mers, the determination of the useable concentration range via the plotting of the aforementioned crystallization curve is a viable alternative to determining a phase diagram, as shown in Fig. 1. As an example of the foregoing, one may refer to Fig. 55 which is a plot of temperature vs. polymer/liquid concentration showing the melt curve at a heating rate of 16C per minute, and crystallization curve for polypropylene and quinoline over a broad concentration range. As may be seen by reference to the crystallization curve, at a cooling rate of 16C per minute, the appropriate concentration range extends from about 20 percent polypropylene to about 70 per-cent polypropylene.
Fig. 56 is a graph of temperature versus polymer/liquid composition for polypropylene and ~,~-bis (2-hydroxy-ethyl) tallowamine. me upper curve is a plot of the melt curve at a heating rate of 16C per minute. The lower curves, in descending order, are plots of the crystallization curves at cooling rates of 8C, 16C, 32C, and 64C, per minute.
The curves demonstrate two concurrent phenomena which occur when the cooling rate is increased. First, the flat portion of the curve demonstrating a relative stable temperature of crystallization across a broad concentration range, is lower-ed with increased cooling rate showing that the faster the rate of cooling, the lower the actual crystallization tem-6'7~

perature.
The second observable phenomenon is the change in the slope of the crystallization curve which occurs with chan-ges in the rate of cooling. Thus, it appears that the flat region of the crystallization curve is expanded when the cooling rate is increased. Accordingly, one may assume that by increasing the rate of cooling, one may correspondingly increase the operable concentration range for forming the microporous structures of the present invention and for practicing the processes of the instant invention. From the foregoing it is apparent that to determine the operable con-centration ranges for a given system, one need only prepare a few representative concentrations of polymer/liquid and cool the same at some desired rate. After the crystalliza-tion temperatures have been plotted, the operable range of concentrations will be quite apparent.
Fig. 57 is a graph of temperature versus polymer/
liquid concentration for polypropylene and dioctyl phthalate.
The upper curve represents the melt curve for the system over a range of concentrations and the lower curve represents the crystallization curve over the same concentration range. As the crystallization curve does not exhibit any flat region over which the crystallization temperature remains substantial-ly constant for a range of concentrations, one would not ex-pect the polypropylene/dioctyl phthalate system to be capable of forming microporous structures, and, indeed, it does not.
To appreciate the excellent correlation between the phase diagram method of determining operable concentration ran-ges of polymer and liquid and the crystallization method of making such a determination, one may refer to Figs. 58 and 59.

Fig. 58 is a phase diagram for a low molecular weight poly-06'7~

ethylene and diphenyl ether polymer/liquid system, determined by a conventional liaht scattering technique utillzing a thermally controlled vessel. From the phase diagram of Fig.
58, it appears that Tm is at about 135C and ~m is at about 7 percent polymer. Furthermore, it is apparent that at about 45 percent polymer concentration, the cloud point curve inter-sects the freezing point depression curve, thus indicating an operable concentration range of about 7 percent polymer to about 45 percent polymer.
One may compare the operable range determined from Fig. 58 to the range determinable from Fig. 59 which shows melt curves of the same system at heating rates of 8C and 16C/minute and crystallization curves for said system at cooling rates of 8C and 16C/minute. From the crystalliza-tion curves it appears that the substantially flat portion thereof extends from somewhat below 10 per cent polymer con-centration to approximately 42-45 per cent polymer, depending on the cooling rate. Thus, the results obtained from the crystallization curves agree surprisingly well with the re-sults obtained from the cloud point phase diagram.
For non-crystalline polymers it is believed that one may refer to a temperature vs. concentration plot of the glass transition temperature, as an alternative to referring to a phase diagram such as that of Fig. 1. Thus, Fig. 60 is a graph of temperature vs. concentration for the glass transi-tion temperature of low molecular weight polystyrene, supplied by Pennsylvania Industrial Chemical Corporation under the designation Piccolastic* D-125, and l-dodecanol, at various concentration levels.
From Fig. 60 it is apparent that from about 8 per-* Trade Mark ilZC)~i'7~

cent polymer to about 50 percent polymer, the glass transi-tion temperature for the polystyrene/l-dodecanol is essential-ly constant. It has therefore been proposed that the concen-trations along the substantially flat portion of the glass transition curve would be operable in the practice of the instant invention, analogous to the flat portion of the crystallization curves previously discussed. It thus appears that a viable alternative to determining the phase diagram for non-crystalline polymer systems is to determine the glass transition curve and to operate in the substantially flat region of such a curve.
In all of the foregoing Figs., the crystallization temperatures were determined with a DSC-2, differential scan-ning calorimeter, manufactured by Perkin-Elmer, or comparable equipment. Further effects of cooling rates as the practice on the present invention will be discussed hereinbelow.
After one has chosen the desired synthetic thermo-plastic polymer, the compatible liquid and the potentially operable concentration range, one needs to choose, for example, the actual concentration of polymer and liquid which will be utilized. In addition to considering, for example, the theoretically possible concentration range, other functional considerations should be employed in determining the propor-tions used for a particular system. Thus, insofar as the maximum amount of liquid which should be utilized is concerned, the resulting strength characteristics must be taken into account. More particularly, the amount of liquid used should accordingly allow the resulting microporous structure to have sufficient minimum "handling strength" to avoid collapse of the microporous or cellular structure. On the other hand, the selection of the maximum amount of resin, viscosity limi-6;7~

tations of the particular equipment utilized may dictate the tolerable maximum polymer or resin content. Moreover, the amount of polymer used should not be so great as to result in closing off the cells or other areas of microporosity.
The relative amount of liquid used will also, to some extent, be dependent upon the desired effective size of the microporosity, as, for example, the particular cell and pore size requirements for the ultimate application involved.
Thus, for example, the average cell and pore size tend to increase somewhat with increasing liquid content.
In any event, the utility of a liquid and the oper-able concentration thereof, for a particular polymer, can be readily determined by experimentally using the liquid as has been described.
The parameters previously discussed should, of course, be followed. Indeed, as should be appreciated, blends of two or more liquids can be used, and the utility of a par-ticular blend can be ascertained as described herein. Also, while a particular blend may be useful, one or more of the liquids may conceivably be unsuitable individually.
As may be appreciated, the particular amount of liquid employed will likewise be often dictated by the par-ticular end use application. As illustrative examples of spe-cific examples, utilizing high density polyethylene and ~,~-bis(2-hydroxyethyl) tallowamine, useful microporous products can be made by utilizing, by weight, from about 30 to about 90% amine, 30 to 70 being preferred. With low density poly-ethylene and the same amine, the amount of liquid can useful-ly be varied within the range from about 20 to 90%, 20 to 80 -being preferred. In contrast, when diphenylether is used asthe liquid, useful low density polyethylene systems contain no more than about 80% of the liquid, a maximum of about 60% being preferred. When l-hexadecene is used with low density poly-ethylene, amounts up to about 90% or more may be readily uti-lized. When polypropylene is used with the tallowamine previously described, the amine may be suitably employed in amounts of from about 10 to 90%, with a maximum amount of no more than about 85% being preferred. With polystyrene and 1-dodecanol, the concentration of the alcohol can vary from about 20 to about 90%, with from about 30 to about 70% being pre-ferred. When styrene-butadiene copolymers are employed, the amine content may range from about 20 to about 90%. When a decanol and styrene-butadiene copolymer (i.e. -SBR) system is used, the liquid content can suitably vary from about 40 to about 90%, with diphenylamine, the liquid content is suitable within the range of from about 50 to about 80%. When micro-porous polymers are formed from the amine and an ethylene-acrylic acid copolymer, the liquid content may vary within the range of from about 30 to about 70%, with diphenyl ether, the liquid content may vary from about 10 to about 90%, as is the case when dibutylphthalate is used as the solvent.
Following the formation of the solution, the same may then be processed to provide any desired shape or configu-ration. In general, and depending upon the particular system involved, the thickness of the article can vary from a thin film of about 1 mil. or less up to a relatively thick block of thickness of about 2 1/2 inches or even more. Ihe ability to form blocks thus allows the microporous material to be proces-sed into any desired intricate shape, as by using conventional extrusion, injection molding or other related techniques. The practical considerations involved in determining the range of thicknesses which can be made from a particular system include liZ~6'71 the rate of viscosity build-up which the system undergoes as it cools. Generally, the higher the viscosity, the thicker the structure can be. The structure can accordingly be of any thickness so long as gross phase separation does not occur, i.e. - 2 discernible layers become visually apparent.
It will be appreciated that if liquid-liquid phase separation is allowed to take place under thermodynamic equilibrium conditions the result will be a complete separa-tion into two distinct layers. One layer consisting of molten polymer containing the soluable amount of liquid and a liquid layer containing the soluable amount of polymer in the liquid.
mis condition is represented by the binodial line in the phase diagram in Figs. 1 and lA. It is apparent that a limi-tation as to the size of object which may be prepared is governed by the heat transer characteristics of the compo-sition for if the object is thick enough and the heat trans-fer is poor enough the rate of cooling in the center of the object may be slow enough to approach thermodynamic equili-brium conditions and result in a distinct layer phase separa-tion as previously described.
Increased thicknesses may also be achieved by theaddition of minor amounts of thixotropic materials. For ex-ample, the addition of commercially available colloidal sili-ca prior to cooling significantly increases useful thicknesses yet does not adversely affect the characteristic microporous structure. The particular amounts to be used can be readily determined.
As is apparent from the above discussion, regard-less of the type of processing (e.g. - casting into a film or the like), the solution must be cooled down to form what behaves as, and appears as, a solid. The resulting material llZ~ 7~

should have sufficient integrity so that it will not crumble upon handling, as in one's hand. A further test to ascertain whether the requisite system possesses the desired structure is to employ a solvent for the liquid employed but not for the polymer. If the material disintegrates, the system employed did not satisfy the necessary criteria.
The rate of cooling of the solution may be varied within wide limits. Indeed, in the usual case, no external cooling need be employed, and it is satisfactory merely to, for example, cast a film by pouring the hot liquid system onto a metallic surface heated to a temperature which allows the drawing of the film or, alternatively, forming a block by pouring onto a substrate at ambient conditions.
The rate of cooling, as previously discussed must be sufficiently fast so that the liquid-liquid-phase separa-tion does not occur under thermodynamic equilibrium conditions.
Furthermore, the rate of cooling may have substantial effect upon the resultant microporous structure. For many polymer/
liquid systems,if the rate of cooling is sufficiently slow, but still satisfying the aforementioned criteria, then the liquid-liquid phase separation will result at substantially the same time in the formation of a plurality of liquid drop-lets of substantially the same size. If the cooling rate is such that the plurality of liquid droplets does form, as long as all other conditions discussed herein have been satisfied, the resultant microporous polymer will have the cellular micro-structure, as previously defined.
In general, it is believed that the unique struc-tures of the microporous polymers of the present invention are obtained by cooling the liquid system to a temperature below the binodial curve, as shown in Fig. 1, so that liquid-liquid 6'71 phase separation is initiated. At this state, nuclei will begin to form, consisting principally of pure solvent. When the rate of cooling is such that the cellular microstructure results, it is also believed that as each such nucleus con-tinues to grow, it becomes surrounded by a polymer rich region which increases in thickness as it becomes depleted of liquid.
Eventually, this polymer-rich region resembles a skin or film covering the growing droplet of solvent. As the polymer-rich region continues to thicken, the diffusion of additional sol-vent through the skin decreases; and the growth of the liquiddroplet correspondingly decreases until it effectively stops, the liquid droplet having reached its maximum size. At this point, the formation of a new nucleus is more probable than continued growth of the large solvent droplet. However, to - achieve this mode of growth, it is necessary that nucleation be initiated by spinodal decomposition rather than by binodial decomposition.
me cooling is thus carried out in such a fashion as to form at substantially the same time a plurality of liquid droplets of substantially the same size in a continuous poly-mer phase. If this deccmposition mode does not take place, the cellular structure will not result. The appropriate decompo-sition mode is achieved, in general, by employing conditions which insure that the system does not achieve thermodynamic equilibrium until at least the nucleation or droplet growth has been initiated. Process-wise, this can be accomplished by merely allowing the system to cool without subjecting it to mixing or other shear forces. The time parameter may also be significant where relatively thick blocks are being formed, making more rapid cooling desirable in such instances.
Within the range over which cooling results in the l~Z~1~'71 formation of a plurality of liquid droplets, there is a general indication that the rate of cooling may affect the size of the resulting cells, with increasing rates of cooling resulting in smaller cells. In this connection, it has been observed that an increase in the cooling rate from about 8C./minute will apparently result in decreasing the cell size in half for a polypropylene microporous polymer. Accordingly, external cool-ing may be utilized, if desired, to control the ultimate cell and pore size, as will be discussed in more detail.
The manner in which the interconnecting passageways or pores are formed in the cellular structure is not fully understood. However, and while the applicant does not wish to be bound by any particular theory there are various possible mechanisms that serve to explain this phenomenon, each of which is consistent with the concept described herein. Ihe formation of the pores may accordingly be due to thermal shrinkage of the polymer phase upon cooling, the liquid solvent droplets behaving as incompressible spheres when the solvent has a smaller expansion coefficient than the polymer. Alternatively, and as has been pointed out, even after the solvent droplets have reached their maximum size, the polymer-rich phase will still contain some residual solvent and vice versa. When the system continues to cool, additional phase separation may ac-cordingly occur. The residual solvent in the polymer-rich skin can therefore diffuse to the solvent droplet, reducing the volume of the polymer-rich skin and increasing the volume of the solvent droplet. Conceptually, this may weaken the polymer skin; and the volume increase of the solvent or liquid phase may result in internal pressure which is capable of bursting through the polymer skin, connecting adjacent solvent droplets. Related to this last mechanism, the polymer may 11'~0~

redistribute itself into a more compact state as the residual liquid migrates out of the polymer skin, as by crystallization when this type of polymer is employed. In such a situation, the resulting polymer skin w~ould likely shrink and have im-perfections or apertures, likely located in the areas of par-ticular weakness~ The weakest areas would, it can be expected, be located between adjacent liquid droplets; and, in such a situation, the apertures would form between adjacent liquid droplets and result in the interconnection of the solvent droplets. At any rate, and regardless of the mechanism, the interconnecting pores or passageways inherently result when the process is carried out as has been described herein.
An alternative explanation of the mechanism by which the pores are formed is based on the "Marangoni effect", which has been discussed in Marangoni, C, Nuovo Cimento [2], 5-6.239 (1871, [3~, 3,97,193 (1878) and Marangoni, C. Ann. Phys. Lpz.
(1871), 143,337. The Marangoni effect has been utilized to explain the phenomenon occurring when alcoholic beverages spontaneously reflux off the sides of drinking glasses, parti-cularly,the mechanism occuring when a condensed droplet flowsback into the bulk of the liquid. The fluid of the droplet first penetrates that of the bulk, followed by the rapid re-treat of part of the fluid back into the droplet. It has been hypothesized that a similar physical phenomenon is occurring with the liquid droplets which have formed as a result of the liquid-liquid phase separation. Thus, one droplet may encoun-ter another and the fluid of one may penetrate that of the other, followed by rapid separation of the two droplets, per-haps then leaving a portion of the liquid connecting the two droplets and forming the basis for the interconnecting pores of the cellular structure. For a more recent discussion of ~2!067~L

the Marangoni effect, one may refer to Charles & Mason, J.
Colloid Sc:, 15, 236-267 (1960).
If the cooling of the homogeneous solution occurs at a sufficiently fast rate, liquid-liquid phase separation may occur under non-equilibrium thermodynamic conditions, but substantial solidification of the polymer may occur so rapidly that essentially no nucleation and subsequent growth may occur. In such an instance there will be no formation of a plurality of liquid droplets and the resulting microporous polymer will not have the distinct cellular structure.
~ hus, under some circumstances it is possible to ob-tain different microporous structures by use of exceptionally high cooling rates. For example, when a solution of 75 parts of N,N-bis(2-hydroxyethyl) tallowamine and 25 parts of poly-propylene is cooled at rates varying from about 5C to about 1350C per minute, the cellular microstructure results. The main effect of different cooling rates in the foregoing range on the composition is the alteration of the absolute cell size. Where cooling rates of about 2000C/minute are achieved, the microstructures take on, for example, a fine lacey, non-cellular appearance. When a solution of 60 parts of N,N-bis(2-hydroxyethyl) tallowamine and 40 parts of polypropylene are treated in the same fashion, cooling rates in excess of 2000C per minute must be achieved before the lacey non-cellular structure is obtained.
To investigate the effect of cooling system rate on the cell size of the cellular structure and to investigate the rate of cooling necessary for transition from production of the cellular structure to production of a structure having no distinct cells, various concentration of polypropylene and N,N-bis~2-hydroxyethyl) tallowamine were prepared as Lif~l;967~L

homogeneous solutions. To accomplish such an investigation, the DSC-2, previously discussed, was utilized in conjunction with standard X-ray ~quipment, and a scanning electron mlcro-scope. As the DSC-2 is capable of a maximum cooling rate of about 80C/minute, a thermal gradient bar was also utilized.
The thermal gradient bar was a brass bar which was capable of having a temperature differential of greater than 2000C
across its one meter length, upon which samples could be placed.
An infrared camera was utilized to determine the tem-peratures of the samples by first focusing the camera on a pan which was placed in the closest of the ten bar sites to a temperature of 110C, as measured with a thermocouple. The camera emissivity control was then adjusted until the camera temperature readout agreed with the thermocouple reading.
For any given run, the camera was focused on a loca-tion at which a given pan containing the sample solution was to cool. The pan with the sample was then placed on the thermal gradient bar for two minutes. As the pan was removed from the bar to be placed in the field of the camera, a stopwatch was started. As soon as the camera indicated that the pan was at a temperature of 110C, the stopwatch was stopped and the time recorded. Thus, the determined cooling rates were based on the time needed for the sample to cool over a tem-perature range of approximately 100C.
It was found that the controlling limitation on the rate of cooling was not the amount of material being cooled.
It was noted that although heavier samples cooled more slowly than light ones, the silicon oil which was used on the bottom of the pan for thermal conductivity between the pan and bar has significant influence on the rate of cooling. Thus the l~Z~671 highest cooling rates were obtained by placing a pan without any silicon oil on an ice cube and the slowest cooling rates were obtained with a pan having a heavy coating of silicon oil which was placed onto a piece of paper.
Five samples of polypropylene were prepared contain-ing from 0 percent N,N-bis(2-hydroxyethyl~ tallowamine to 80 percent of said amine, for use in investigating the effect of cooling rate on the resultant structures. Approximately 5 milligrams of each of said samples were heated on the DSC-2 inside of sealed pans at 40C per minute to a holding temper-ature of 175C for the sample containing 20 percent poly-propylene, 230C for the sample containing 40 percent poly-propylene, 245C for the sample containing 60 percent poly-propylene, 265C for the sample containing 80 percent poly-propylene and 250C for the 100 percent polypropylene.
Each of the samples were heated to and maintained at the appropriate holding temperature for five minutes prior to being cooled. After the samples were cooled at the desired cooling rate, the N,N-bis(2-hydroxyethyl) tallowamine was extracted from the sample with methanol and the sample an analyzed. The results of the study are summarized in TABLE I
showing the size-s of the cells in microns, in the resulting compositions. All cell sizes were determined by making measurements from the respective scanning electron micro-graphs.

0~'71 TABLE I
Cooling Rate 5C/Min. 20C/Min. 40C/Min. 80C/Min.
Composition 0% Amine None( ) None( ) None(l) None( ) 20% Amine 0 5(2) 0 5(2) None( ) None( ) 40% Amine 2 5(4) 2 o(4) 2.o(4) o 7(5) 60% Amine 4.0 3.0 2.0 1.5( ) 80% Amine 0.5 4.0 3.0 3 o(6) (1) Some irregular holes present (2) Approximation of largest cell size

(3) Porosity probably too small to measure

(4) Some small cells present at 1/10 size of larger cells

(5) Additional cells present too small to measure

(6) Some formation of non-cellular structure An additional cooling rate study was conducted utilizing samples of 20 percent polypropylene and 80 percent N,N-bis(2-hydroxyethyl) tallowamine on the thermal gradient bar. Five of such samples were cooled at various rates from a melt temperature of 210C and the results are summarized in TABLE II, showing the sizes of the cells in microns, the same procedure being utilized as for obtaining the data for TABLE
I.
TABLE II
Cooling Rate 200C 870C/Min. 1350C/Min. 1700C/Min.
Composition 80% Amine 0.5-3 0.5-1.5 1.5-2.5 Non-cellular From TABLES I and II it is apparent that for increas-ing cooling rates, the size of the cells in the resulting com-positions decrease, in general. Furthermore, with respect tothe polymer/liquid system comprised of 20 percent polypropyl-112()6'~1 ene and 80 percent N,N-bis(2-hydroxyethyl) tallowamine, it is apparent that at a cooling rate between about 1350C per minute and 1700C per minute a transition is completed in the nature of the resultant polymer from essentially cellular to non-cellular. Such a transition in the resultant structure cor-responds to the fact that the polymer becomes substantially solidified after liquid-liquid phase separation has been ini-tiated but prior to the formation of a plurality of liquid droplets, as previously discussed.
Additionally five samples of 40 percent polypropyl-ene and 60 percent N,N-bis(2-hydroxyethyl) tallowamine were prepared and cooled at rates from 690C per minute to over 7000C per minute, from melt temperatures of 235C, in accordance with the procedure discussed previously. It was determined that for such a concentration of polypropylene and said amine, the transition from cellular to non-cellular occurs at about 2000C per minute.
Finally, to investigate the crystallinity of struc-tures prepared over a range of cooling rates, three samples of 20 percent polypropylene and 80 percent N,N-bis(2-hydroxy-ethyl) tallowamine were prepared and cooled at rates of 20C, 1900C and 6500C per minute. From the DSC-2 data for such samples it was determined that the degree of crystallinity in the three samples was essentially equivalent. mus it appears that variations in the cooling rate have no significant effect upon the degree of crystallinity of the resulting structures.
However, it was determined that as the rate of cooling was significantly increased, the crystals which were produced became less perfect, as expected.
Having formed the homogeneous solution of polymer and liquid and having cooled the solution in an appropriate 6'71 manner to produce a material having suitable handling strength, the microporous product may be thereafter formed by removing the liquid by, for example, extracting with any suitable sol-vent for the liquid which is, likewise, quite obviously, a non-solvent for the polymer in the system. The relative mis-cibility or solubility of the liquid in the solvent being employed will, in part, determine the effectiveness in terms of the time required for extraction. Also, if desired, the extracting or leaching operation can be carried out at an elevated temperature below the softening point of the polymer to lessen the time requirements. Illustrative examples of useful solvents include isopropanol, methylethyl ketone, tetrahydrofuran, ethanol and heptane.
The time required will vary, depending upon the liquid employed, the temperature used and the degree of ex-traction required. More particularly, in some instance, it may be unnecessary to extract 100% of the liquid used in the system and minor amounts may be tolerated, the amount which can be tolerated being dependent upon the requirements of the intended end-use application. The time required may accord-ingly vary anywhere in the range of from several minutes or perhaps less to more than 24 hours or even more, depending upon many factors, including the sample thickness.
Removal of the liquid can also be achieved by other known techniques. Illustrative examples of other useful removal techniques include evaporation, sublimation and dis-placement.
It should be noted in addition, when using conven-tional liquid extraction techniques, the cellular microporous polymer structures of the present invention may exhibit re-lease of a liquid contained in the structure in a fashion 11~06~7~

which approaches zero order, i.e., the rate of release may be essentially constant after, perhaps, an initial period at a high release rate. In other words, the rate of release may be independent of the amount of the liquid that has been released thus, the rate at which the liquid is extracted after, for example, three-fourths of the liquid has been re-moved from the structure is approximately the same as when the structure was one-half filled with liquid. An example of such a system exhibiting an essentially constant release rate is the extraction of ~,~-bis(2-hydroxyethyl) tallowamine from polypropylene with isopropanol as the extractant. Also, in any situation, there probably will be an initial induction period before the rate of release becomes identifiable. When release of a liquid is allowed to proceed by evaporation, the rate of release tends to be first order.
When the cooling of the polymer/liquid solution oc-curs such that the plurality of liquid droplets form as pre-viously discussed, and the liquid removed therefrom, the resulting microporous product forms a relatively homogeneous cellular structure comprising, on the microscale, a series of substantially spherical, enclosed microcells distributed subs-tantially uniformly throughout the structure. Adjacent cells are interconnected by smaller pores or passageways. This basic structure can be seen from the photomicrographs of Figs.
4 and 5. It should be appreciated that the individual cells are, in fact, enclosed but appear open in the photomicro-graphs due to the fracturing involved in the sample prepar-ation for taking the photomicrographs. On a macroscale, at least for the crystalline polymers, the structure appears to have planes similar to the fracture planes along the edges of crystal growth (see Fig. 2) and, as can be seen from Fig. 3, ~lZC~6`7~

is coral-like in appearance. The cellular microstructure may further be analogized to zeolite clay structures, which con-tain definite "chamber" and "portal" regions. The cells cor-respond to the larger chamber areas of zeolite structures while the pores correspond to the portal regions.
In general, in the cellular structure the average diameter of the cells will vary from about 1/2 micron to about 100 microns, about 1/2 to about 50 microns being more typical whereas the average diameter of the pores or interconnecting passageways appears to be typically about a magnitude smaller.
Thus, for example, if the cell diameter in a microporous poly-mer structure of the present invention is about 1 micron, the average diameter of the pore or interconnecting passageway will be about 0.1 micron. As has been pointed out previously, the cell diameter and also the diameter of the pore or pas-sageway will be dependent upon the particular polymer-liquid system involved, the rate of cooling and the relative amounts of polymer and liquid utilized. However, a broad range of cell to pore ratios are possible, as,for example, from about 2:1 to about 200:1, typically, from about 5:1 to about 40:1.
As can be seen from the several Figures, it may be considered that some of the exemplary cellular microporous polymer products do not possess the unique microcellular structure which has been described herein. It must, however, be appreciated that this structure can, in some instances, be masked by additional modifications resulting from the particu-lar liquid or polymer involved or the relative amounts em-ployed. mis masking may be in whole or in part, ranging from small polymer particles attached to the walls of the cells to gross "foliage-type" polymer build-ups which, in the mi-crographs, tend to completely mask the basic structure. Thus, ~lZ~16'7~

for example, and as can be seen from Figs. 21 and 25, small polymer balls are adhered to the cell cavities of the struc-tures. This additional formation can be understood by refer-ence to the nucleation and growth concept previously described~
Thus, in systems with extremely high solvent or liquid con-tent, the maximum cavity size will typically be comparatively large. This likewise means that the time required for the cavity or droplet to reach its maximum size will similarly be increased. During this time, it is possible for additional nuclei to form nearby. Iwo or more nuclei may then come into contact with one another prior to each reaching its maximum size. In such instances, the resulting cellular structure has less integrity and somewhat less regularity than the basic structure previously described. Moreover, even after the liquid droplets have reached maximum size, depending upon the system involved, the solvent or liquid phase may still contain some amount of residual polymer or vice versa. In such situations, as the system continues to cool, some additional residual phase separation may occur. When the residual polymer simply separates out of solution, spheres of polymer can form as shown in Figs. 21 and 25.
On the other hand, if the residual polymer diffuses to the polymer skin, the walls will appear fuzzy and irregular, thus providing the "foliage-type" structure. This "foliage-type" structure may only partially mask the basic structure, as seen in Figs. 28 and 29 or it may wholly mask the struc-ture as shown in Fig. 6.
The "foliage-type" structure is also more prone to occur with certain polymers. Thus, the microporous low den-sity polyethylene structures, perhaps due to the solubilityor the like of the polyethylene in the particular liquids 06't~

employed, typically provide this sort of structure. This can be observed from Fig. 14. Further, when the levels of liquid employed are extremely high, this will also occur with polymers such as polypropylene which otherwise exhibit the basic structure. This can be readily observed by contrast-ing the "foliage-type" structure of the microporous product of Fig. 6 with the basic structure of Fig. 8 in which the polymer content is 40% by weight comparison to the 10% poly-propylene in the structure illustrated in Fig. 6.
For most applications, it is preferred to utilize a system which results in the formation of the basic cellular structure. me relative homogeneity and regularity of this structure provides predictable results, such as are required in filtration applications. However, the foliage-type struc-ture may be more desirable where relatively high surface area structures are desired such as in ion exchange or various ad-sorptive processes.
As can be likewise observed, some of the structures have small holes or apertures in the walls of the cells. This phenomenon can also be understood by reference to the nuclea-tion and growth concept. Thus, in a section of the system in which a few spatially associated liquid droplets have al-ready reached their maximum size, each droplet will be enclosed by a polymer-rich skin. However, in some instances, some solvent may be trapped between the enclosed droplets but cannot continue its migration to the larger droplets due to impenetrability of the skins. Accordingly, in such instances, a nucleus of the liquid may form and grow, resulting in small cavity embedded adjacent to the larger droplets. After ex-traction of the liquid, the smaller droplets will appear asa small hole or aperture. This can be observed in the micro-~.Z067~

porous structures shown in Figs, 11-12 and 20.
Another interesting characteristic of the cellular structures of the present invention relates to the surface area of such structures.
m e theoretical surface area of the cellular micro-porous structure consisting of interconnected spherical cavi-ties of about 5 microns in diameter is approximately 2-4 sq meters/gm. It has been found that microporous polymers pro-duced by the instant invention need not be limited to the theoretical limit of surface area. Determination of surface area by the B,E.T. method described in Brunauer, S., Emmet, P.H., and Teller, E. "The Adsorption of Gases in Multimolecu-lar Layers" J. Am. Chem, Soc., 60,, 309,-16 (1938), has shown surface areas far in excess of the theoretical model which is not related to the void space, as shown in TABLE III, for microporous polymers made from polypropylene and N,~-bis(2-hydroxyethyl) tallowamine.
TABLE III
% VOID SPECIFIC SURFACE AREA
2089.7 96.2 m2/gm 72.7 95.5 60.1 ~8.0 50.5 99.8 28.9 ?38.5 Surface area may be reduced by careful annealing ofthe microporous polymer without affecting the basic structure.
Microporous polypropylene prepared at 75% void space using N,~-bis(2-hydroxyethyl) tallowamine as the liquid component was extracted and dried at temperatures not exceeding room temperature and subsequently heated to affect the surface -4~-6'7~

area. m e initial surface area was 96.9 m /gm. After eleven 40 minute heat periods at 62C, the surface area fell to 66 m2/gm. Further heating at 60C for an additional 66 hours decreased the surface area to 51.4 m2/gm. Treatment of ano-ther sample at 90C for 52 hours decreased the surface area from 96.9 to 33.7 m2/gm. The microporous structure was not signifieantly changed when examined by scanning electron mi-croscopy. These results are summarized in Table IV.
TABLE IV
TreatmentSurfaee area (m /gm) % Change none 96.9 eleven, 40 min.
treatments at 62C 66.0 32%
Above plus 66 hours at 60C 51.4 47%
52 hours at 90C 33.7 65%
It should be quite apparent that one of the unique features of the cellular struetures of the present invention relates to the existence of both distinet, substantially spherieal, enclosed microcells whieh are uniformly distributed throughout the structure and distinet pores which interconnect said eells, said pores being of a smaller diameter than said cells. Furthermore, said cells and interconnecting pores have essentially no spatial orientation, and may be classified as being isotropic. Thus there is no preferred direction, as for example, for flow of a liquid through the structure. This is in marked contrast to prior art materials which do not exhibit such a cellular structure. Many prior art systems have a non-descript structure which lacks any structural con-figuration capable of definition. It is therefore quitesurprising that a microporous structure can be made having ~1~06`7~

such a degree of uniformity, which may be especially desirable for many applications needing highly uniform materials.
The cellular structure may be defined in terms of the ratio of the average diameter of the cells ("C") to the diameter of the pores ("P"). Thus, the C/P ratio as previous-ly discussed may vary from about 2 to about 200, about S to about 100 being typical and about 5 to about 40 being even more typical. Such a C/P ratio distinguishes the cellular structure of the present invention from any previous prior art microporous polymeric product. As there is no known prior art synthetic thermoplastic polymeric structure having distinct cells and pores, all such prior art materials must be consi-dered to have a cell to pore ratio of 1.
Another means of characterizing the cellular struc-tures of the present invention is by a sharpness Factor, "S".
me S factor is determined by analyzing a mercury intrusion curve for the given structure. All mercury intrusion data discussed in this application was determined by use of a Micromeritics Mercury Penetration Porosimeter, Model 910 series. The S value is defined as the ratio of the pressure at which 85 percent of the mercury penetrated to the pressure at which 15 percent of the mercury penetrated. This ratio is a direct indication of the variation in pore diameter across the central 70 percent of the pores in any given sample, as pore diameter is equal to 176.8 divided by the pressure in p.s.i.
The S value, then, is a ratio of the diameter of the pores at which 15 percent of the mercury has intruded to the diameter of the pores at which 85 percent of the mercury has intruded. The range for 1 to 15 percent and 85 to 100 percent of mercury intrusion is ignored in determining the S

06'71 factor. me range from 0 to 15 percent is ignored as pene-tration in this range may be due to cracks introduced into the material as a result of the freeze-fracturing to which the material was subjected prior to performing the mercury in-trusion study. Also, the range from 85 to 100 percent is ignored as data in such a range may be due to compression of the sample rather than to actual penetration of the mercury into the pores.
Characteristic of the narrow range of pore size exhibited by the composition of the present invention, the usual S value for such structures is in the range of from about 1 to about 30, about 2 to about 20 being typical and about 2 to about 10 being more typical.
m e average size of the cells in the structure range from about 0.5 to about 100 microns, from about 1 to about 30 microns being typical, from about 1 to about 20 microns being more typical. As indicated the cell size may vary depending on the particular resin and compatible liquid utilized, the ratio of polymer to liquid, and the cooling rate employed to form the particular microporous polymer. The same variable will also have an effect upon the average size of the pores in the resulting structure, which usually varies from about 0.05 to about 10 microns from about 0.1 to about 5 microns being typical, and from about 0.1 to about 1.0 micron being more typical. All references to a cell and/or pore size through-out this application, relate to the average diameter of such cell or pore, in microns, unless otherwise stated.
By determining the foregoing factors, cell size, pore size, and S, for the cellular microporous polymers of the present invention, one may concisely define the cellular microporous polymers of the present invention. A particularly _47 `7~

useful means of so defining the polymers in terms of the log of the cell to pore ratio ("log C/P") and the log of the ratio of the sharpness function S to the cell size ("log S/C").
Accordingly, the cellular microporous polymers of the present invention have a log C/P of from about 0.2 to about 2.4 and a log S/C o from about - 1.4 to about 1.0, more usually, said polymers have a log C/P of from about 0.6 to about 2.2 and a log S/C of from about - 0.6 to about 0.4~
~he non-cellular structure of the present invention which results from the cooling of the homogeneous solution at such a rate that the polymer substantially solidifies prior to the formation of the plurality of liquid droplets, may be cha-racterized primarily with respect to the narrow pore size dis-tribution of the material in conjunction with the actual pore size and the spatial uniformity of the structure.
Particularly, the non-cellular microporous polymers may be characterized by a sharpness function, S, as previously described with respect to the cellular structures. The S
values exhibited by the non-cellular structure range from about 1 to about 30, about 1 to about 10 being preferred and about 6 to about 9 being more preferred. However, when the pore size of the material ranges from about 0.2 to about 5 microns, the S value will range from about 5 to about 10 and will typically range from about 5 to about 10.- Such S values for olefinic and oxidation polymers having microporosity of such a size has been unknown heretofore, except in the case of highly oriented, thin films made by a stretching technique. As previously indicated, the porous polymers of the present invention are substantially isotropic. Thus a cross-section of the polymers taken along any spatial plane will reveal essentially the same structural features.

~Z(~6'~1 The pore sizes of the non-cellular structures of the present invention are usually in the range from about 0.05 to about 5 microns, from about 0.1 to about 5 microns being typical, and from about 0.2 to 1.0 micron being more typical.
It is apparent that a surprising feature of the pre-sent invention is the ability to produce isotropic microporous structures from olefinic and oxidation polymers, with the structures having porosity in the range from about 0.2 to about 5 microns and a sharpness value from about 1 to about 10. It is especially surprising that such structures may be made in the form, not only of thin films, but also in the form of blocks and intricate shapes.
When forming a film or block by pouring onto a substrate such as metal plate, for example, the surface of the microporous polymer structure of the present invention which is in contact with the plate will comprise a surface skin that is non-cellular. The other surface, in contrast, is typically predominantly open. The thickness of the skin will vary some-what in accordance with the particular system as well as the particular process parameters employed. However, typically, the thickness of the skin is approximately equal to the thick-ness of a single cell wall. Depending upon the particular conditions, the skin may range from one which is wholly im-pervious to the passage of liquids to one exhibiting some degree of liquid porosity.
If a solely cellular structure is desired for the ultimate application, the surface skin may be removed by any of several techniques. As illustrative examples, the skin could be removed by employing any one of several mechanical means such as abrading, puncturing the skin with needles or fracturing the skin by passing the film or other structure llZC~6`7~

through differential speed rollers. Alternatively, the skin could be removed by microtoming. The skin may also be removed by chemical means, i.e. - by hrief contact with a suitable sol-vent for the polymer.
For example, when a solution of polypropylene in N,N-bis(2-hydroxyethyl) tallowamine is continuously extruded as a thin film onto an endless stainless steel belt conveyor, application of a small amount of liquid solvent upon the belt immediately prior to the solution application zone will ef-fectively remove the surface formed at the solution-steel in-terface. Useful liquids are materials such as isoparaffinic hydrocarbons, decane, decalin, xylene and mixtures such as xylene-isopropanol and decalin-isopropanol.
However, for some end use applications, the presence of the skin will not only not be a detriment but will be a necessary component. For example, as is known, ultrafiltration or other membrane-type applications utilize a thin, liquid im-penetrable film. Accordingly, in such applications, the micro-porous portion of the structure of the present invention would have particular utility as a support for the surface skin which would be functioning membrane in such applications.
Wholly cellular structures can also be directly prepared by various techniques. Thus, for example, the polymer-liquid system could be extruded into air or a liquid medium such as, for example, hexane.
The microporous polymer structures of the present invention, as has been previously discussed, have cell and pore diameters with extremely narrow size distributions which are indicative of the unique structures and their relative homogeneity. The narrow size distribution of the pore dia-meters is apparent from mercury intrusion data, as can be seen 6'71 from Figs. 30-33. The same general distribution is obtained regardless of whether the structure is in the form of a film (Figs. 30-32) or a block (Fig. 33). The characteristic pore size distribution of the microporous structure of the present invention is in marked contrast to the significantly broader pore size distributions of prior microporous polymer products achieved by prior processes, such as, for example, those set forth in U.S. patents 3,310,505 and 3,378,507, as will be discussed in greater detail in connection with the Examples.
For any of the microporous polymers made in accord-ance with the present invention, the particular end use appli-cation will typically determine the amount of void space and pore size requirements. For example, for prefilter applica-tions, the pore size will typically be above 0.5 microns while, in ultrafiltration, the pore sizes should be less than about 0.1 micron.
In applications where the microporous structure serves, in effect, as a receptacle for a functionally useful liquid strength considerations dictate the amount of void space where controlled release of the contained functional liquid is involved. Similarly, in such cases, the pore size will be dic-tated by the rate of release desired, smaller pore sizes tend-ing to provide slower rates of release.
Where the microporous structure is to be utilized to convert a liquid polymer additive such as a flame retard-ant to a solid, some minimum strength is generally desired;
but, consistent with this minimum, it will typically be desired to utilize as much liquid as possible since the polymer serves merely as a receptacle or carrier.
From the foregoing discussions it should be appre-ciated that in accordance with one aspect of the present in-ll'Z~6'7~

vention, microporous products containing a functionally use-ful liquid such as polymer additive (e.g. - flame retardant~
may be prepared which behave,as, and may be processed as, a solid. Tc this end, the resulting microporous polymer may be reloaded with the desired functional liquid. This can be ac-complished by conventional absorption techniques, and the amount of liquid taken up will be essentially the same as the amount of liquid used in forming the microporous polymer in the first instance. Any useful organic liquid may be employed so long as, of course, the liquid is not a solvent for the polymer, or otherwise attacks or degrades, the polymer at the working temperature. The microporous products containing the functionally useful liquid may be formed from or by using microporous polymers having either the cellular or non-cellu-lar structure, as the matrix in which the liquid is incor-porated.
Similarly, such microporous products can be prepared by a displacement technique. In accordance with this embodi-ment, the microporous polymer intermediate is first prepared and the liquid is then displaced, whether with the desired functionally useful liquid or with an intermediate displacing liquid. In either case, rather than extracting the liquid used in forming the microporous polymer intermediate, the displacement is carried out by conventional pressure or va-cuum displacement or infusion techniques. Any functional or intermediate displacing liquid may be used which could be used as an extracting liquid to form the microporous polymer, i.e. - is a non-solvent for the polymer yet has some solu-bility or miscibility with the liquid being displaced. As is apparent, minor amounts of the displaced liquid or liquids may remain following displacement. The requirement of the 112~'7:1 end use will typically dictate the extent of the displacement desired, thus, amounts of about 1 to about 10% by weight may be tolerated in some applications. If required, multiple dis-placements and/or using liquids that can be readily removed by evaporation allows removal of essentially all of the liquid or liquids being displaced, i.e. - less than about 0.03 or so weight per cent of residual liquid can be achieved. From the economic standpoint, it will generally be desirable to utilize a displacing liquid which has a boiling point sufficiently different from the liquid being displaced to allow recovery and reuse. For this reason, it may be desirable to utilize an intermediate displacing liquid.
As may also be apparent from the foregoing examples of useful polymer-liquid systems, a further method of prepar-- ing a polymer-functionally useful liquid material involves utilizing the microporous polymer intermediate without fur-ther processing since numerous functionally useful liquids have been found to be operable as the compatible liquid with particular polymers to form the solid microporous polymer intermediate. mus, intermediates which behave as solids can be directly made with liquids useful as lubricants, surfactants, slip agents, moth repellents, pesticides, plas-ticizers, medicinals, fuel additives, polishing agents, sta-bilizers, insect and animal repellents, fragrances, flame retardants, antioxidants, odor masking agents, antifogging agents, perfumes and the like. For example, with low den-sity polyethylene,useful intermediates containing a lubricant or a plasticizer may be provided by employing either an ali-phatic or aromatic ester having eight or more carbon atoms or a nonaromatic hydrocarbon having nine or more carbon atoms.

Useful products containing a surfactant and/or wetting agent llZ(~6'~1 may be formed with low density polyethylene by using a poly-ethoxylated aliphatic amine having eight or more carbon atoms or a noniQnic surfactant. With polypropylene, surfactant -containing intermediates can be provided by utilizing di-ethoxylated aliphatic amines having eight or more carbon atoms.
Polypropylene intermediates containing slip agents may be prepared by using a phenylmethyl polysiloxane while low density polyethylene slip agent intermediates are formed by employ-ing an aliphatic amide having twelve to twenty-two carbon atoms. Low density polyethylene fuel additive intermediates may be prepared by utilizing an aliphatic amine having eight or more carbon atoms or an aliphatic dimethyl tertiary amine having twelve or more carbon atoms. The tertiary amines may also form useful additive intermediates with methylpentene polymers. High and low density polyethylene intermédiates containing a stabilizer can be formed by using an alkyl aryl phosphite.
Intermediates of low density polyethylene including an antifogging agent may be provided by utilizing the glycerol mono or diester of a long chain fatty acid having at least ten carbon atoms. Intermediates having flame retardants in-corporated therein may be prepared with high and low density polyethylene, polypropylene, and a polyphenylene oxide -polystyrene blend by using a polyhalogenated aromatic hydro-carbon having at least four halogen atoms per molecule. Use-ful materials should, of course, be liquid at the phase sepa-ration temperature as described herein. Other systems which have been found useful will be identified in connection with the Examples presented hereinafter.
Furthermore, for polypropylene, high density poly-ethylene and low density polyethylene, certain classes of 6'7~

ketones which have been found to be especially useful as animal repellants may be employed generally in the practice of the present invention. Such ketones may include saturated aliphatic ketones having from 7 to 19 carbon atoms, unsatura-ted aliphatic ketones having from 7 to 13 carbon atoms, 4-t-amyl cyclohexanone, and 4-t-butyl cyclohexanone.
The following Examples are presented to more fully explain the present invention and are merely illustrative of the present invention and are not intended as a limitation upon the scope thereof. Unless otherwise indicated, all parts and percentages are by weight.
The porous polymer intermediates and the micropo-rous polymers described in the Examples presented hereinafter were prepared according to the following procedure:
A. Porous Polymer Intermediates:
me porous polymer intermediates are formed by ad-mixing a polymer and a compatible liquid, heating the mix-ture to a temperature which is usually near or above the softening temperature of the resin such that homogeneous solution is formed, and then cooling the solution without subjecting it to mixing or other shear forces to form a macroscopically solid homogeneous mass. When solid blocks of the intermediates are to be formed, the homogeneous solu-tion is allowed to assume a desired shape by pouring it into an appropriate receptacle, which is usually made of metal or glass, and the solution allowed to cool under ambient room conditions, unless otherwise noted. The rate of cooling under room temperature conditions will vary, depending on items such as sample thickness and composition, but will usually be in the range of from about 10 to about 20C per minute. The receptacle is typically cylindrical in shape with a diameter 112~6'~1 of from about 0.75 to about 2.5 inches and the solution is typically poured to a depth of from about 0.25 to about 2.0 inches. When films of the intermediates are formed, the homogeneous solution is poured onto a metal plate which is heated to a temperature sufficient to allow the drawing of the solution into a thin film. The metal plate is then placed into contact with a dry ice bath to rapidly cool the film below its solidification temperature.
B. Porous Polymer:
me microporous polymer is formed by extracting the compatible liquid used to form the porous polymer intermediate, typically by repetitively washing the intermediates in a sol-vent such as isopropanol or methylethyl ketone, then drying the solid microporous mass.
EXAMPLES
~ he following examples and tables illustrate some of the various polymer/compatible liquid combinations which are useful in forming the porous polymer intermediates of this invention and various prior art or commercially available microporous products. Solid blocks of the intermediates were formed for all of the exemplified combinations and, when so indicated in a table, thin films of the intermediate were also formed, using the procedure described above. As indi-cated in the following tables, many of the intermediate com-positions were used to form the microporous polymers of this invention, by using a suitable solvent to extract the compa-tible liquid from the intermediate composition, and subse-quently removing said solvent, as by evaporation.
Many of the compatible liquids w~ich are illus-trated in the following examples are, as indicated in thetables, functional liquids which are useful not only as '7~

compatible liquids but also as flame retardants, slip agents, and the like. mus, the intermediate compositions which are formed with such functional liquids are useful as solid poly-mer additives and the like, as well as intermediates in the formation of porous polymers. me functional liquids which appear in the following examples are indicated to be such by the presence of one or more of the following symbols under column "Type of Functional Liquid": AF (Antifogging Agent), AO (Antioxidant); AR (Animal Repellant); FA (Fuel Additive), FG(Fragrance), FR (Flame Retardant); IR (Insect Repellant);
L (Lubricant); M (Medicinal); MR (Moth Repellant); OM (Odor Masking Agent); P (Plasticizer); PA (Polishing Agent);
PE (Pesticide); PF (Perfume); S (Slip Agent); SF (Surfactant), and ST (Stabilizer).
EXAMPLES 1 to 27 Examples 1 through 27 in Table V illustrate the form-ation of homogeneous porous polymer intermediates, in the form of cylindrical blocks having a radius of about 1.25 inches and a depth of about 2 inches, from high density poly-ethylene ("HDPE") and the compatible liquids found to be use-ful, using the standard preparation procedure. The high den-sity polyethylene was supplied by Allied Chemical under the designation Plaskon * AA 55-003, having a melt index of 0.3g/
10 minutes and a density of 0.954g/cc. Many of the exempli-fied intermediates were extracted to form porous polymers, as indicated in the Table.
me details of preparation and the type of functionally useful liquid noted are set forth in Table V:
* Trade Mark '71 TABLE V
HDPE
Type of Functional Ex. ~o. Liquid Type and Liquid % Liq. C. Liauid Saturated Aliphatic Acids 1 decanoic acid* 75 230 --~
Primary Saturated Alcohols 2 decyl alcohol* 75 220 PF
3 l-dodecanol* 75 220 ---Secondary Alcohols 4 2-undecanol* 75 220 ---6-undeconal* 75 230 ---Aromatic Amines 6 ~,~ diethylaniline* 75 230 ---Diesters

7 dibutyl sebacate* 70 220 L, P

8 dihexyl sebacate* 70 220 L, P
Ethers

9 diphenyl ether 75 220 PF
benzyl ether* 70 220 PF
Halo~enated 11 hexabromobenzene 70 250 FR
12 hexabromobiphenyl 75 200 FR
13 hexabromocyclodecane 70 250 FR
14 hexachlorocyclopentadiene 70 200 FR
octabromobiphenyl 70 280 FR
Terminally Double Bonded Hydrocarbons 16 l-hexadecene* 75 220 ---* qhe liquid was extracted from the solid.

TABLE V (continued) HDPE Type of Functional Ex. No. Liquid Type and Liquid /O Liq. C. Liquid Aromatic Hydrocarbons 17 diphenylmethane* 75 220 OM
18 naphthalene* 70 230 MR
Aromatic Ketones 19 acetophenone 75 200 PF
Aromatic Esters butyl benzoate* 75 200 L, P
Miscellaneous .
21 N,N-bis(2-hydroxyethyl) tallowamine (1) * 70 250 ---22 dodecylamine* 75 220 ---23 N-hydrogenated tallow-diethanol amine 50 240 SF
24 Firemaster BP-6 (2) 75 200 ---Phosclere P315C* (3) 75 220 ST
26 Quinoline 70 240 M
27 dicocoamine (4) 75 220 ---* The liquid was extracted from the solid.
(1) A permanent internal antistatic agent having the following properties was used: Boiling Point 1 mm Hg, C., 215-220, Specific Gravity 90F., 0.896, Viscosity, SSU, 90F., 476.
(2) Michigan Chemical Corporation's trademark for its hexa-bromobiphenyl, a flame retardant having the following properties was used: Softening Point, C., 72; Density, 25C, g/ml, 2.57, Viscosity, cps, 260-360 (Brookfield No. 3 spindle at 110C.).

llZ~)6'7~

TABLE VI
LDPE
Type of Functional Ex. No.tl) Liquid Type and Liquid % Liq. C. Liquid Aliphatic Saturated Acids 28 caprylic acid* 70 210 ---29 decanoic acid* 70 190 ---hexanoic acid* 70 190 ---31 lauric acid* 70 220 ---32 myristic acid* 70 1~9 ---33 palmitic acid* 70 186 ---34 stearic acid* 70 222 ---undecanoic acid* 70 203 ---Unsaturated Aliphatic Acids 36 erucic acid (2)* 70 219 ---37 oleic acid* 70 214 PA
Aromatic Acids 38 phenyl stearic acid* 70 214 ---39 xylyl behenic acid* 70 180 ---Miscellaneous Acids Acintol FA2(Tall Oil Acids)(3)* 70 204 ---* The liquid was extracted from the solid.
(1) Union Carbide Company's Bakelite** polyethylene having the following properties was used: Density, g/cm3, 0.922: Melt Index, g/10 min., 21.
(2) This is an acid with a density of 0.8602 g/cc and a melting point of 33-34C.
(3) Arizona Chemical Company's trademark for a mixture of fatty acids. The composition and physical properties are: Fatty Acid Composition (98.2% of total), Linoleic, Non-conjugated, %, 6, Oleic, %, 47, Saturated, %, 3, Other Fatty acids, %, 8, Specific Gravity, 25/25C., 0.898, Viscosity, SSU, 100F., 94.
** Trademark l~ZI~)6'~1 TABLE VI (continued) LDPE Type of Functional Ex. No. Liquid Type and Liquid /O Liq. C. Liquid Miscellaneous Acids (continued) 41 olefin acid L-6* 70 206 ---42 olefin acid L-9* 70 186 ---43 olefin acid L-ll* 70 203 --44 Rosin acid* 70 262 ---tolylstearic acid 70 183 ---Primar~ Saturated Alcohols 46 cetyl alcohol* 70 176 ---47 decyl alcohol* 70 220 PF
48 l-dodecanol* 75 200 ---49 l-heptadecanol* 70 168 ---nonyl alcohol* 70 174 PF
51 l-octanol* 70 178 ---52 oleyl alcohol* 70 206 FA
53 tridecyl alcohol 70 240 ---54 l-undecanol* 70 184 ---undecylenyl alcohol* 70 199 ---Secondary Alcohols 56 dinonyl carbinol* 70 201 PF
57 diundecyl carbinol 70 226 ---58 2-octanol 70 174 ---59 2-undecanol* 70 205 ---Aromatic Alcohols l-phenylethanol* 70 184 PF
61 l-phenyl-l-pentanol 70 196 ---62 phenyl stearyl alcohol* 70 206 ---63 nonyl phenol* 70 220 SF, PE

* The liquid was extracted from the solid.

llZ~)~ 71 TABLE VI (continued) LDPE Type of Functional Ex. No. Liquid Type and Liquid /O Liq. C. Liquid Cyclic Alcohols 64 4-t-butyl cyclohexanol* 70 190 PE
menthol* 70 206 PF
Other -OH Containinq Compounds 66 Neodol-25 (1)* 70 180 ---67 polyoxyethylene ether of oleyl alcohol (2) 70 268 SF
68 polypropylene glycol-425* (3) 70 --- SF
Aldehydes 69 salicylaldehyde* 70 188 PF
Primary Amines dimethyldodecylamine 70 200 FA
71 hexadecylamine* 70 207 FA
72 octylamine* 70 172 FA
73 tetradecylamine* 70 186 FA
SecondarY Amines 74 bis(l-ethyl-3-methyl pentyl) amine* 70 190 ---* me liquid was extracted from the solid.
(1) Shell Chemical Company's trademark for its synthetic fatty alcohol of 12-15 carbon atoms.
(2) Croda, Inc.'s, Volpo 3 surfactant having the following properties was used: Acid Value, max., 2.0; Haze Pt., 1%
aq. soln., insoluble; I~LB value, calculated, 6.6; Iodine Value, Wijs, 57-62; pH of 3% aq. soln., 6-7, hydroxyl value, 135-150.
(3) Union Carbide Company's trademark for its glycol having the following properties: Apparent Specific Gravity, 20/20 C., 1.009; Avg. hydroxyl number, mg. KOH/g, 265; Acid Number, mg KOH per g sample, max., 0.2; pH at 25C. in 10:6 iso-propanol water soln., 4.5-6.5.

'71 TABLE VI (continued) LDPE Type of Functional E~x. No. Liquid Type and Liquid /O Liq. C. Liquid Tertiary Amines N,N-dimethylsoya-amine* (1) 70 198 FA
76 N,N-dimethyltallowamine* (2) 70 209 FA
Ethoxylated Amines 77 N-stearyl diethanol amine 75 210 SF, AF
Aromatic Amines 78 aminodiphenylmethane 70 236 ---79 N-sec-butylaniline 70 196 ---~,N-diethylaniline* 70 --- ---81 N,N-dimethylaniline* 70 169 ---82 diphenylamine 70 186 A0, PE
83 dodecylaniline* 70 204 ---84 phenylstearyl amine* 70 205 ---N-ethyl-o-toluidine* 70 182 ---86 p-toluidine* 70 184 ---Diamines 87 1,8-diamino-p-menthane 70 188 ---88 N-erucyl-1,3-propane* diamine 70 220 ---Miscellaneous Amines -branched tetramine L-PS (3) 70 242 ---cyclododecylamine* 70 159 ---* The liquid was extracted from the solid.
(1) A tertiary amine having the following properties was used:
Cloud point, F., ASTM 100; Specific Gravity, 25/4C., 0.813, Viscosity, SSU, at 25C., 59.3.
0 (2) A tertiary amine having the following properties was used:
Melting Range, E`., 28 to 41: Cloud Point, F., 60; Speci-fic Gravity, 25/4C., 0.803, Viscosity, SSU, 25C., 47.
(3) N-phenylstearo -1, 5, 9, 13 azatridecane.

~lZ[)~'71 TABLE VI (continued) LDPE Type of Functional Ex. No. Liquid Type and Liquid /O Liq. C. Liquid Amides 91 cocoamide* (1) 70 245 ---92 N,N-diethyltoluamide 70 262 IR
93 erucamide* (2) 70 250 L, P
94 hydrogenated tallowamide* 70 250 L, P
octadecylamide (3) 70 260 L, P
96 N-trimethylolpropane stearamide 70 255 L, P
Aliphatic Saturated Esters -97 ethyl laurate* 70 175 ---98 ethyl palmitate* 70 171 ---99 isobutyl stearate* 70 194 L
100 isopropyl myristate* 70 192 ---101 isopropyl palmitate* 70 285 ---102 methyl caprylate 70 182 ---103 methyl stearate* 70 195 ---104 tridecyl stearate 70 202 L
Aliphatic Unsaturated Esters 105 butyloleate* 70 196 L
106 butylundecylenate* 70 205 ---107 stearylacrylate* 70 205 ---* The liquid was extracted from the solid.
(1) An aliphatic amide having the following properties was used:
Appearance, Flake., Flash Point, C., Approx., 174; Fire Point, C., Approx., 185.
0 (2) An amide having the following properties was used: Specific Gravity, .88; Melting Pt., C., 99-109; Flash Pt., C., 225.
(3) Octadecylamide having the following properties was used:
Appearance, Flake, Flash Point, C., Approx., 225, Fire Point, C., Approx., 250.

)67~

TABLE VI (continued) LDPE Type of Functional Ex. No. Liquid Type and Liquid o/O Liq. C. Liquid Alkoxy Esters 108 butoxyethyl oleate* 70 200 ---109 butoxyethyl stearate* 70 205 ---Aromatic Esters 110 benzylacetate . 70 198 ---111 benzylbenzoate* 70 242 L, P
112 butylbenzoate* 70 178 L, P
113 ethylbenzoate* 70 200 L, P
114 isobutylphenylstearate* 70 178 L, P
115 methylbenzoate* 70 170 L, P
116 methylsalicylate* 70 200 L, P, PF
117 phenyllaurate* 70 205 L, P
118 phenylsalicylate 70 211 L, P, M, F
119 tridecylphenylstearate* 70 215 L, P
120 vinylphenylstearate* 70 225 L, P
Diesters 121 dibutylphthalate* 70 290 L, P
122 dibutyl sebacate* 70 238 L, P
123 dicapryl adipate 70 204 L, P
124 dicapryl phthalate 70 204 ---125 dicapryl sebacate 70 206 L, P
126 diethylphthalate* 70 280 IR
127 dihexylsebacate 70 226 ---128 dimethylphenylene distearate * 70 208 ---129 dioctyl maleate 70 220 ---130 di-iso-octyl phthalate 70 212 ---131 di-iso-octyl sebacate 70 238 ---* The liquid was extracted from the solid.

~Z~tj'7~

TABLE VI (continued) LDPE
Type of Functional x. ~o. Liquid Type and Liquid /0 Liq. C. Liquid Esters-Polyethylene Glycol 132 PEG 400 diphenylstearate 70 326 ---Polyhydroxylic Esters 133 castor oil 70 270 ---134 glycerol dioleate * (1) 70 230 AF
135 glycerol distearate * (2) 70 201 AF
136 glycerol monooleate * (33 70 232 AF
137 glycerol monophenylstearate 70 268 ---138 glycerol monostearate * (4) 70 211 AF
139 trimethylolpropane mono-phenylstearate 70 260 ---Ethers 140 dibenzylether* 70 189 PF
141 diphenylether* 75 200 ---* ~he liquid was extracted from the solid.
(1) A glycerol ester having the following properties was used, Flash Point, COC, F., 520; Freezing Point, C., 0; Visco-sity at 25C., cp, 90; Specific Gravity 25/20C., 0.923-0.929.
(2) A solid with a melting point of 29.1C.
(3) A glycerol ester having the following properties was used;
Specific Gravity, 0.94-0.953; Flash Point, COC, F., 435;
Freezing Point, C., 20; Viscosity at 25C., cp, 204.
(4) A glycerol ester having the following pro~erties was used;
Form at 25C., Flakes; Flash Point, COC, F., 410; Melting Point, C., 56.5-58.5.

O~j'71 TABLE VI (cont~nued) LDPE
Type of Functional Ex. ~o. Liquid Type and Liquid % Liq. C. Liquid Haloqenated Ethers 142 4-bromodiphenylether* 70 180 FR
143 FR 300 BA (1) 70 314 FR
144 hexachlorocyclopentadiene* 70 196 PE, FR
145 octabromobiphenyl* 70 290 FR
Terminal Double Bond Hydrocarbon 146 l-nonene* 70 174 L
Internal Double Bond Hydrocarbon 147 3-eicosene* 70 204 ---148 2-heptadecene* 70 222 ---149 2-nonadecene* 70 214 ---150 9-nonadecene* 70 199 ---151 2-nonene* 70 144 L
152 2-undecene 70 196 ---Aromatic Hydrocarbons 153 diphenylmethane 75 200 PF
154 trans-stilbene* 70 218 ---155 triphenylmethane 70 225 ---Aliphatic Ketones 156 dinonylketone* 70 206 ---157 distearylketone* 70 238 ---158 2-heptadecanone 70 205 ---* The liquid was extracted from the solid.
(1) Dow Chemical Company's trademark for its decabromodiphenyl oxide fire retardant having the following properties was used: Bromine, %, 81-83, Melting Point, min. 285C., Decom-position Temp., DTA, 425C.

'7~

TABLE VI (continued) LDPE
Iype of Functional Ex. ~o. Liquid Type and Liquid /O Liq. C. Liquid Aliphatic Ketones (continued) 159 8-heptadecanone* 70 183 ----160 2-heptanone* 70 152 ---161 methylheptadecylketone* 70 225 ---162 methylnonyl ketone* 70 170 AR
163 methylpentadecyl Xetone* 70 210 AR
164 methylundecyl ketone 70 205 ---165 2-nonadecanone 70 214 ---166 10-nonadecanone 70 194 ---167 8-pentadecanone* 70 178 ---168 ll-pentadecanone* 70 262 ---169 2-tridecanone* 70 168 ---170 6-tridecanone* 70 205 ---171 6-undecanone* 70 188 ---Aromatic Ketones 172 acetophenone* 70 190 PF
173 benzophenone 70 245 PF
Miscellaneous Ketones 174 9-xanthone* 70 220 PE
Phosphorous Compounds 175 trixylenyl phosphate* 70 304 FR
Miscellaneous 176 N,N-bis(2-hydroxyethyl) tallowamine 70 210 ---177 bath oil fragrance No. 5864K 70 183 FG
* The liquid was extracted from the solid.

11~0~i'71 TABLE VI (continued) LDPE
Type of Functional Ex. No. Liquid Type and Liquid % Liq. C. Liquid Miscellaneous (continued) 178 EC-53 Styrenated nonyl phenol (l)* 70 191 AO
179 Mineral oil 50 200 L
180 Muget hyacinth 70 178 FG
181 Phosclere P315C* 70 200 ---182 Phosclere P576 (2)* 70 210 AO
183 Quinalidine 70 173 ---184 Quinoline* 70 230 ---185 Terpineol Prime No. 1 70 194 M, F
186 Firemaster BP-6 75 200 FR
187 benzylalcohol/l-heptadecanol (50/50)* 70 204 ---188 benzylalcohol/l-heptadecanol (75/25)* 70 194 ___ * The liquid was extracted from the solid.
(1) Akzo Chemie ~v.'s trademark for its styrenated hindered phenol (2) Akzo Chemie Nv.'s styrenated hindered phenol.
Photomicrographs of the porous polymers of Examples 38 and 122 are illustrated in Figs. 28 and 29, respectively.
The photomicrographs, at 2000X amplification, show the cel-lular structure with a significant amount of "foliage" uni-formly present throughout the samples.
EXAMPLES 189 to 193 Examples 189 through 193 in Table VII illustrate the formation of homogeneous porous polymer intermediates, by pouring the solution into a glass dish to form cylindridal blocks having a radius of about 1.75 inches and a depth of )6'71 about 0.25 inch, except where indicated, from "Noryl" polymer and the compatible liquids found to be ùseful, using the stan-dard preparation procedure. In the indicated instances, the microporous polymer was likewise prepared.
The details of preparation and the type of function-ally useful liquid noted are set forth in Table VII:
TABLE VII

Type of Functional 10Ex. No.(l) Liquid Type and Liquid /O Liq. C. Liquid Aromatic Amine 189 diphenylamine 75 195 PE, AO
Diester 190 dibutylphthalate 75 210 L
Haloqenated Hydrocarbon 191 hexabromobiphenyl (2) 70 315 FR
Miscellaneous 192 N,N-bis(2-hydroxyethyl) tallowamine* 75 250 ---193 N,N-bis(2-hydroxyethyl) tallowamine 90 300 ---(1) General Electric Company's "Noryl", a blend of polyphenyl-ene oxide condensation polymer with polystyrene, having the following properties was used: Specific Gravity, 73F., 1.06, Tensile Strength, psi. at 73F., 9,600, Elongation at break, % at 73F., 60, Tensile Modulus, psi. at 73F., 355,000, nad Rockwell Hardness, Rll9.
(2) The "Noryl" microporous polymers formed with hexabromo bi-phenyl and N,N-bis(2-hydroxyethyl) tallowamine were poured to depths of 0.5 inch.
A photomicrograph of the microporous polymer of Example 192 is illustrated in Fig. 25. The photomicrograph, at 2500X amplification, shows the microcellular structure with spherical resin deposits on the walls of the cells.
EXAMPLES 194 to 236 Examples 194 through 236 in Table VIII illustrate the formation of homogeneous porous polymer intermediates, in the )6'71 form of cylindrical blocks having a radius of about 1.25 inches and a depth of about 0.5 inch, from polypropylene ("PP") and the compatible liquids found to be useful, using the standard preparation procedure. In addition, in the indicated examples, blocks of about 6 inches in depth and/or thin films were made.
Also, as indicated, the microporous polymer was prepared.
The details of preparation and the type of function-ally useful liquid noted are set forth in Table VIII:
TABLE VIII
pp Type of Functional Ex. No~(l) Liquid Type and Liquid /O Liq. C. Liquid Unsaturated Acid 194 10-undecenoic acid* 70 260 M
Alcohols 195 2-benzylamino-1-propanol70 260 ---196 Ionol CP* 70 160 A0 197 3-phenyl-1-propanol 75 230 ---198 salicylaldehyde ~70 185 PF
Amides 199 ~,N-diethyl-m-toluamide75 240 IR
200 aminodiphenylmethane*70 230 ---201 benzylamine* 70 160 ---202 N-butylaniline 75 200 ---203 1,12-diaminododecane*70 180 ---204 1,8-diaminooctane 70 180 ---* The liquid was extracted from the solid.

l~ZO~'71 TABLE VIII (continued) PP
Type of Functional Ex. No.(l) Liquid Type and Liquid /0 Liq. C. Liquid Amides (continued) 205 dibenzylamine* 75 200 ---206 N,N-diethanolhexylamine* 75 260 ---207 N,N-diethanoloctylamine* 75 250 ---208 ~,N-bis- B -hydroxyethyl cyclohexylamine 75 280 ---209 ~,N-bis-(2-hydroxyethyl) hexylamine 75 260 ---210 N,~ bis-(2-hydroxyethyl) octylamine 75 260 ---* me liquid was extracted from the solid.
(1) Phillips Petroleum Company's "Marlex"**polypropylene having the following properties was used: Density, g/cm3, 0.908:
Melt Flow, g/iO min. Melting Point, F., 340, Tensile Strength at yield, psi, 2"/min., 5000, Hardness Shore D, 73.
** Trade Mark ~Z~6 7~1 TABLE VIII (continued) PP
Iype of Functional Thin Ex. ~o. Liquid Type and Liquid % Liq. C. Liquid Film Esters 211 benzylacetate* 75 200 ~
212 benzylbenzoate* 75 235 L, P, PF ---213 butylbenzoate 75 190 L, P ---214 dibutylphthalate* 75 230 L, P yes 215 methylbenzoate 70 190 L, P, PF ---216 methylsalicylate* 75 215 L, P, PF ---217 phenylsalicylate* 70 240 P ---Ethers 218 dibenzylether 75 210 PF ---219 diphenylether* 75 200 PF yes Halocarbons 220 4-bromodiphenylether* 70 200 FR ---221 1,1,2,2 tetrabromoethane* 70 180 FR ---222 1,1,2,2 tetrabromoethane* 90 180 FR ---Ketones 223 benzylacetone 70 200 --- ~--224 methylnonylketone 75 180 --- ---* The liquid was extracted from the solid.

6'71 TABLE VIII (continued) PP
Type of Functional m in Ex. No. Liquid Type and Liquid /O Liq. C. Liquid Film Miscellaneous 225 N,~-bis(2-hydroxyethyl) tallowamine* (1) & (2) 75 200 --- yes 226 ~,N-bis(2-hydroxyethyl) cocoamine (2) 75 180 --- ---227 butylated hydroxy toluene 70 160 A0 ---228 D.C. 550 Silicone Fluid (3) 50 260 S, L ---229 D.C. 556 Silicone Fluid* 70 190 S, L ---231 ~-hydrogenated rapeseed di-ethanol amine* 75 210 SF ---232 N-hydrogenated tallow di-ethanol amine 75 225 SF ---233 Firemaster BP-6 75 200 FR ---234 ~BC oil 75 190 --- ---235 Quinaldine* 70 200 --- ---236 Quinoline* 75 220 M -~-* The liquid was extracted from the solid.
(1) A block of about 6 inches in depth was also prepared.
(2) A permanent internal antistatic agent, having the following physical properties was used: Boiling Point, lmm Hg, C., 170, Viscosity, SSU, 90F, 367.
(3) Dow Corning's trade mark for its phenylmethyl polysiloxane having the following properties was used: Viscosity 115CS
and serviceable from -40 to 450F. in open systems, and to 600F. in closed systems.
Photomicrographs of the porous polymer of Example 225 are illustrated in Figs. 2 through 5. The photomicrographs of Figs. 2 and 3, at 55X and 550X amplification, respectively, show the macro structure of the microporous polymer. me photomicrographs of Figs. 4 and 5, at 2,200X and 5,500X ampli-fication, respectively, show the microcellular structure of llZ()6;7~

the polymer as well as the interconnecting pores.
EXAMPL~S 237 to 243 Examples 237 through 243 in Table IX illustrate the formation of homogeneous porous polymer intermediates, in the form of cylindrical blocks having a radius of about 1.25 in-ches and a depth of about 0.5 inch, from polyvinylchloride ("PVC") and the compatible liquids found to be useful, using the standard preparation procedure. Many of the exemplified intermediates were extracted to form porous polymers, as in-dicated in the Table.
The details of preparation and the type of function-ally useful liquid noted are set forth in Table IX:

~lZ~t~i 71 TABLE IX
PVC
Type of Functional Ex. No.(l) Liquid T~pe and Liquid /O Liq. C. Liquid Aromatic Alcohols 237 4-methoxybenzyl-alcohol 70 150 PF
Other -(OH) Containinq Compounds 238 1-3,-dichloro-2-propanol* 70 170 ---239 menthol* 70 180 PF
240 10-undecene-1-ol* 70 204-Haloqenated 241 Firemaster T33P* (2) 70 165 FR
2~2 Firemaster T13P* (3) 70 175 FR
Aromatic Hydrocarbons 243 trans-stilbene 70 190 ----* The liquid was extracted from the solid.
(1) The polyvinylchloride used was of dispersion grade made by American Hoechst, having an inherent viscosity of 1.20, a density of 1.40 and bulk density of 20.25 pounds per cubic foot.
(2) Michigan Chemical Corporation's trademark for its tris (1,3-dichloroisopropyl) phosphate fire retardant having the following properties: Chlorine content, theoretical, %, 49.1, Phosphorous content, theoretical, %, 7.2, Boiling Point, 4mm Hg, abs. C., 200 (decomposes at 200C.) Re-fractive Index, 1.50.9, Viscosity, Brookfield, 73F., Centipoises, 2120.
Structure: [ (ClCh2)2CHO~3 P-0 (3) Michigan Chemical Corporation's trademark for its tris-halogenated propylphosphate flame retardant having the fol-lowing properties: Specific Gravity, at 25C./25C., 1.88;
Viscosity, at 25C., centistokes, 1928, Refractive Index, 1.540, pH, 6.4, Chlorine, %, 18.9, Bromine, %, 42.5, Phos-phorous, %, 5.5.
A photomicrograph of the porous polymer of Example 242 is illustrated in Fig. 27. me photomicrograph, at 2000X

amplification, shows the extremely small cell size of this microporous polymer in contrast to the cell structure exempli-llZ6)6'~1 fied by Figs. 7, 13, 18, 20, and 24, wherein the cell size is larger and more readily observable at a comparable magnifica-tion. m e photomicrograph also shows the presence of a large amount of resin masking the basic cell structure.
EXAMPLES 244 to 255 Examples 244 through 255 in Table X illustrate the for-mation of homogeneous porous polymer intermediates, in the form of cylindrical blocks having a radius of about 1.25 inches and a depth of about 2.0 inches, from methylpentene ("MPP") polymer and the compatible liquids found to be useful, using the stand-ard preparation procedure. Many of the exemplified interme-diates were extracted to form porous polymers, as indicated in the Table.
The details of preparation and the type of function-ally useful liquid noted are set forth in Table X:

~lZ~16 71 TABLE X
MPP
Type of Functional Ex. ~o.(1) Liquid Type and Liquid /O Liq. C. Liquid Saturated Aliphatic Acid 244 decanoic acid* 75 230 ---Saturated Alcohols 245 l-dodécanol* 75 230 ---246 2-undecanol* 75 230 ---247 6-undecanol* 75 230 ---Amine 248 dodecylamine 75 230 FA
Esters 249 butylbenzoate* 75 210 L, P, PF
250 dihexylsebacate* 70 220 L, P
Ethers 251 dibenzylether* 70 230 PF
* The liquid was extracted from the solid.
0 (1) Mitsui's methylpentene polymer having the following proper-ties was used: Density, g.cc, 0.835; Melting Point C., 235, Tensile Strength at Break, kg/cm2, 230, Elongation at Break %, 30, Rockwell Hardness, R, 85.

TABLE X (continued) MPP

Type of Functional Ex. No Liquid Type and Liquid /O Liq. C. Liquid -Hydrocarbons 252 l-hexadecene* 75 220 ---253 naphthalene* 70 240 MR
Miscellaneous 254 EC-53* 75 230 AO
255 Phosclere P315C* 75 250 ---* me liquid was extracted from the solid.
A photomicrograph of the porous polymer of Example 253 is illustrated in Fig. 22. The photomicrograph, at 2400X am-plification, shows the extremely flattened cell walls, as com-parable to the configuration observed in Fig. 14.
EXAMPLES 256 to 266 Examples 256 through 266 in Table XI illustrate the formation of homogeneous porous polymer intermediates, in the form of cylindrical blocks having a radius of about 1.25 inches and a depth of about 0.5 inch, from polystyrene ("PS") and the compatible liquids found to be useful, using the standard preparation procedure. All of the exemplified intermediates were extracted to form porous polymers.
m e details of preparation and the type of functional-ly useful liquid noted are set forth in Table XI.
TABLE XI

Type of Functional Ex. ~o.~l) Liquid Type and Liquid /O Liq. C. Liquid 256 Firemaster T-13P 70 250 FR
257 hexabromobiphenyl 70 260 FR

~79-6 ~1 j TABLE XI (continued) Type of Functional Ex. No.(l) Liquid Type and Liquid /O Liq. C. Liquid 258 Phosclere P315C 70 270 ---259 Phosclere P576 70 285 A0 260 tribromoneopentylalcohol 70 210 FR
261 FR 2249 (2) 70 240 FR
262 Fyrol CEF (3) 70 250 FR
263 Firemaster T33P (4) 70 210 FR
264 Fyrol FR 2 (5) 70 240 FR
265 dichlorobenzene 80 160 MR, FR
266 l-dodecanol 75 --- ---(1) Monsanto Chemical Company's "Lustrex" polystyrene having the following physical properties was used: Impact Strength, ft.
lb./in notch (Inj. molded), 0.40; Tensile Strength, psi, 7500; Elongation, %, 2.5; Elastic Modulus, psi, XID5, 4.5, Deflection Temp., under load 264, psi, F., 200, Specific Gravity, 1.05; Rockwell Hardness, M-75; Melt Flow, g/10 min., 4.5.
(2) Dow Chemical Corporation's trademark for its fire retardant having composition and properties: Tribromoneopentyl alco-hol, 60%, Voranol CP. 3000 polyol, 40%; Bromine, %, 43;
hydroxyl No. 130, Viscosity, cps, 25C. (approx.) 1600;
Density, gm/cc, 1.45.
(3) Stauffer Chemical Company's trademark for its tris- -chloro-ethyl phosphate fire retardant having the following proper-ties: Boiling Point, at 0.5 mm Hg abs., C, 145, at 760 mm Hg abs., C., decomposes; Chlorine content, wt. %, 36.7, Phosphorous content, wt. %, 10.8; Refractive Index at 20C., 1,4745; Viscosity, cps at 73F. (22.8C.), 40.
(4) Michigan Chemical Corporation's trademark for its tris(l,3-dichloroisopropyl phosphate) fire retardant having the fol-lowing properties: Chlorine content, theoretical, %, 49.1, Phosphorous content, theoretical, %, 7.2; Boiling Point, 4 mm Hg abs., C, 200 (decomposes at 200C.); Refractive Index, 1.5019; Viscosity, Brookfield, 73F., Centipoises, 2120.
Structure: [ (ClCH2)2CHO]3 P-0 (5) Stauffer Chemical Company's trademark for its tris (di-chloropropyl) phosphate flame retardant additive having the following properties: Melting Point, F, Approx., 80; Re-fractive Index nd at 25C., 1.5019; Viscosity, Brookfield at 22.8C., cps, 2120.

.

llZ~6 71 A photomicrograph of the microporous polymer of Exam-ple 260 is illustrated in Fig. 26. Although the cells are small compared to the cells illustrated in Figs. 4, 7, 13, 18, and 25, the basic microcellular structure is present.

This example illustrates the formation of a homogeneous porous polymer intermediate from 30% high impact polystyrene (1) and 70% hexabromobiphenyl, using the standard preparation procedure and heating the mixture to 280C. The polymer inter-

10 mediate thus formed was about 2.5 inches in diameter and about0.5 inch in depth. me hexabromobiphenyl is useful as a flame retardant and the porous intermediate is useful as a solid flame retardant additive.

This example illustrates the formation of a homogeneous porous polymer intermediate from 25% acrylonitrile-butadiene-styrene terpolymer(2) and 75% diphenylamine, using the standard preparation procedure and heating the mixture to 220C. me polymer intermediate thus formed was about 2.5 inches in diame-20 ter and about 2 inches in depth. me microporous polymer wasformed by extracting the diphenylamine. The diphenylamine is useful as a pesticide and antioxidant and the porous polymer intermediate has the same utility.

(1) Union Carbide Company's "Bakelite" polystyrene for injection molding having the following properties was used: Tensile Strength, psi., (1/8" thick) 5000, ultimate elongation (1/8"
thick) 25, Tensile modulus, psi., (1/8" thick) 380,000, Rockwell hardness (1/4 x 1/2 x 5") 90, Specific Gravity, natural 1.04.
(2) Uniroyal's Kralastic* ABS polymer having the following pro-perties was used: Specific Gravity, 1.07, impact strength (1/8" Bar Sample), Izod Notched, 73F., ft. lbs~/in. notch, 1.3-1.9 Tensile Strength, psi., 8,800, and Rockwell Hard-ness, R, 118.
* Trademark llZ~)~ 71 EXAMPLES 269 and 270 me homogeneous porous polymer intermediates were formed from 25% chlorinated polyethylene thermoplastic supplied by Dow, having a melt viscosity of 15 poise, 8 percent crystal-linity, and containing 36 per cent chlorine and 75% N,N-bis(2-hydroxyethyl) tallowamine (Example 270) and 75% chlorinated polyethylene thermoplastic and 25% l-dodecanol (Example 271), using the standard preparation procedure and heating to 220C.
me porous polymer intermediates were about 2.5 inches in dia-meter and about 2 inches in depth.

me homogeneous porous polymer intermediate was formed using the standard preparation procedure and heating to 210C.
from 25% chlorinated polyethylene elastomer, as used in Example 271 and 75% diphenylether. The porous polymer intermediates were about 2.5 inches in diameter and about 2 inches in depth.
The diphenylether is useful as a perfume and the intermediate is also useful in perfumes.
EXAMPLES 272 to 275 Examples 272 through 275 in Table XII illustrate the formation of homogeneous porous polymer intermediates, in the form of cylindrical blocks having a radius of about 1.25 inches and a depth of about 0.5 inch from styrene-butadiene ("SBR") rubber (1) and the compatible liquids found to be useful using the standard preparation procedure. In addition to the cylin-drical blocks, as indicated, thin films were also formed.
The details of preparation and the type of functional-ly useful liquid noted are set forth in Table XII:
(1) Shell Chemical Company's Kraton* SBR polymer having the 3~ following properties was used: Tensile Strength, psi., 3100-4600; Elongation at Break, 880-1300, and Rockwell hardness, Shore A, 35-70.
* Trademark 6~

TABLE XII
SBR

Type of Functional Thin Ex. No. Liquid Type and Liquid~/O Liq. C. Liquid Film 272 N,N-bis(2-hydroxyethyl) tallow amine 80 195 --- yes 273 decanol* 70 190 PF yes 274 diphenylamine 70 200-210 PE, A0 yes 275 diphenylether 70 195 PF yes * The liquid was extracted from the solid EXAMPLES 276 to 278 Examples 276 through 278 in Table XIII illustrate the formation of homogeneous porous polymer intermediates, in the form of cylindrical blocks having a radius of 1.25 inches and ~-a depth of about 0.5 inch from "Surlyn" (1) and the compatible liquids found to be useful, using the standard preparation pro-cedure. In addition to the cylindrical blocks, as indicated, thin films were also formed. Two of the exemplified interme-diates were extracted to form porous polymers, as indicated in the Table.
The details of preparation and the type of functional-ly useful liquid noted are set forth in TABLE XIII:

(1) E. I. du Pont de Nemour's "Surlyn"* ionomer resin 1652, lot number 115478, having the following properties was used:
Density, g/cc, 0.939, Melt Flow Index, decigm./min., 4.4, Tensile Strength, psi., 2850, Yield Strength, psi., 1870 Elongation, %, 580.
* Trademark .~

)6 7~

TABLE XIII
SURLYN

~ype of Functional min Ex. No.(l) Liquid Type and Liquid % Liq. C. Liquid Film 276 N,N-bis(2-hydroxyethyl) tallowamine 70 190 --- yes 277 diphenylether* 70 200 PF yes 278 dibutylphthalate70 195 L yes * me liquid was extracted from the solid.
Photomicrographs of the porous polymer of Example 277 are illustrated in Figs. 23 and 24. Fig. 23, at 255X amplifi-cation, shows the macrostructure of the polymer. Fig. 24, at 2550X amplification, illustrates the microcellular structure of the polymer with slight "foliage" and relatively thick cell walls, as compared with, for example, Fig. 25.

me homogeneous porous polymer intermediate was formed, using the standard preparation procedure and heating to 200C., from a high density polyethylene-chlorinated polyethylene blend, equal parts, and 75% l-dodecanol. me porous polymer intermediate was cast in a film having a thickness of about 20 to 25 mils. The HDPE and CPE were utillzed in previous Examples.
EX~MPLE 280 m e homogeneous porous polymer intermediate was formed, using the standard preparation procedure and heating to 200C., from a high density polyethylene-polyvinylchloride blend, equal parts, and 75% l-doaecanol. me intermediate thus formed was about 2 inches in depth and about 2.5 inches in diameter. m e HDPE and PVC were as utilized in previous Examples.

llZ~)6 71 The homogeneous porous polymer intermediate was formed, using the standard preparation procedure and heating to 200C., from a high density polyethylene/acrylonitrile-butadiene-sty-rene terpolymer blend, equal parts, and 75% l-dodecanol. The intermediate thus formed was about 2 inches in depth and about 2.5 inches in diameter. Ihe HDPE and ABS were as utilized in previous Examples.
EXAMPLES 282 to 285 Examples 282 through 285 in Table XIV illustrate the formation of homogeneous porous polymer intermediates, in the form of cylindrical blocks having a radius of 1.25 inches and a depth of about 2 inches, from low density polyethylene/
chlorinated polyethylene blend, equal parts, and the compatible liquids found to be useful, using the standard preparation pro-cedure. In Example 283, the aforementioned method was employed, but the intermediate was cast into a film having a thickness of about 20 to 25 mils. me LDPE and CPE were as utilized in pre-vious Examples.
The details of preparation and the type of functional-ly useful liquid noted are set forth in Table XIV:
TABLE XIV

Type of Functional Ex. No. Liquid Type and Liquid % Liq. C. Liquid 282 l-dodecanol 75 200 ---283 diphenylether 75 200 PF
284 diphenylether 50 200 PF

285 N,N-bis(2-hydroxyethyl) tallowamine 75 200 ---llZ~6;71 EXAMPLES 286 and 287 The homogeneous porous polymer intermediates were formed from a low density polyethylene/polypropylene blend, equal parts, and 75% N,N-bis (2-hydroxyethyl) tallowamine (Example 286) and low density polyethylene/polypropylene blend, equal parts, and 50% N,N-bis (2-hydroxyethyl) tallowamine (Ex-ample 287) using the standard preparation procedure and heating to 220C. for Example 286 and to 270C. for Example 288. Both porous polymer intermediates were about 2.5 inches in diameter and about 2 inches in depth. m e LDPE and PP were as utilized in previous Examples.

qhe homogeneous porous polymer intermediate was formed, using the standard preparation procedure and heating to 200C., from 50% N,N-bis(2-hydroxyethyl) tallowamine and 50% polypropyl-ene/polystyrene blend (25 parts polypropylene). The porous poly-mer intermediates were about 2.5 inches in diameter and about 2 inches in depth. The PP and PS were as utilized in previous Examples.

me homogeneous porous polymer intermediate was formed, using the standard preparation procedure and heating to 200C., from 75% l-dodecanol and a polypropylene/chlorinated polyethyl-ene blend, equal parts. The porous polymer intermediate was about 2.5 inches in diameter and about 0.5 inch in depth. The PP and CPE were as utilized in previous Examples.
EXAMPLES 290 to 300 Examples 290 through 300 illustrate the polymer-com-patible liquid concentration range useful for the formation of a homogeneous porous polymer intermediate from high density polyethylene and N,N-bis(2-hydroxyethyl) tallowamine. In each Example the intermediates were about 2 inches in depth and about 2.5 inches in diameter. The HDPE was as utilized in previous Examples.
The details of preparation and any physical charac-teristics noted are set forth in Table XV:
TABLE XV
Ex. ~o. /O Liq. C. Remarks _ 290 95 275 very weak no solid integrity:
not operable 291 90 --- very greasy liquid leaching out:
upper liquid limit was exceeded 292 80 250 greasy 293 75 220 greasy 294 70 250 hard solid 296 60 250 hard solid 298 50 240-260 hard solid 299 40 260 hard solid 300 30 200 hard solid A photomicrograph of the porous polymer of Example 300 is illustrated in Fig. 19, at 2000X amplification. The cells àre not clearly visible at this amplification. Fig. 19 can be compared to Fig. 17, at 2475X amplification, wherein the cell sizes are also very small at a similar polymer con-centration of 70%.
EXAMPLES 301 to 311 These examples illustrate the polymer-compatible liquid concentration range useful for the formation of a homo geneous porous polymer intermediate from low density poly-ethylene and N,~-bis(2-hydroxyethyl1 tallowamine. In each example the intermediate was about 0.5 inch in depth and about 2.5 inches in diameter. The LDPE was as utilized in previous Examples.
The details of preparation and any physical charac-teristics noted are set forth in Table XVI:
TABLE XVI
Ex. No. /O Liq. C. Remarks 301 95 275 very weak, no solid integrity;
not operable 302 90 240 very greasy; liquid leaching out;
upper liquid limit was exceeded 303 80 260 hard solid 304 75 210 hard solid 305 70 210 hard solid 306 66 200 hard solid 307 60 280 hard solid 308 50 280-290 hard solid 309 40 285 hard solid 310 30 285 hard solid 311 20 280-300 hard solid Photomicrographs of the porous polymers of Examples 303, 307 and 310 are illustrated in Figs. 14-15 (at 250X and 2500X amplification, respectively), 16 (at 2500X amplifica-tion), and 17 (at 2475X amplification), respectively. The Figures show the decreasing cell size, from very large (Fig~
15, 20% polymer) to very small (Fig. 17, 70% polymer), with increasing polymer content. me relatively flattened cell walls of the 20% polymer, Example 303, are similar to the methyl pentene polymer (Fig. 22) and are observable in Fig. 14.
Fig. 15 is an enlargement showing part of a cell wall illus-trated in Fig. 14. The microcellular structure of the porous polymer is observable in Fig. 16.

liZ~)~ 7~

EXAMPLES 312 to 316 Examples 312 to 316 illustrate the polymer-compatible liquid concentration range useful for the formation of a homo-geneous porous polymer intermediate from low density poly-ethylene and diphenylether. In each example the intermediate was about 0.5 inch in depth and about 2.5 inches in diameter.
The LDPE was as utilized in previous Examples.
The details of preparation and any physical charac-teristics noted are set forth in Table XVII:
TABLE XVII
Ex No. % Liq. C. Remarks 312 90 185 very greasy; no solid integrity;
not operable 313 80 185 very greasy; near upper liquid limit but still operable 314 75 200 wet; strong 315 70 190-200 slightly greasy 316 60 200 hard solid EXAMPLES 317 to 321 Examples 317 to 321 illustrate the polymer-compatible liquid concentration range useful for the formation of a homo-geneous porous polymer intermediate from low density poly-ethylene and l-hexadecene. In each Example the intermediate was about 2 inches in depth and about 2.5 inches in diameter.
The LDPE was as utilized in previous Examples.
The details of preparation and any physical charac-teristics noted are set forth in Table XVIII:

}6 71 TABLE XVIII
Ex. No. /O Liq. C. Remarks 317 90 180 good strength 318 80 180 little strength, operable 319 75 200 little strength, operable 321 50 180 good strength EXAMPLES 322 to 334 These examples illustrate the polymer-liquid concen-tration range useful for the formation of a homogeneous porouspolymer intermediate from polypropylene and N,~-bis(2-hydroxy-ethyl) tallowamine. In each example the intermediate was about 0.5 inch in depth and 2.5 inches in diameter. In addi-tion, as indicated, films were made. The PP was as utilized in previous examples.
The details of preparation and any physical charac-teristics noted are set forth in Table XIX:
TABLE XIX
Ex. ~o. /O Liq. C. Remarks Thin Film 322 90 200 quite wet yes 324 80 200 strong yes 325 75 180 dry and hard yes 326 70 200 --- yes 328 60 210 --- yes 329 50 200 --- yes 330 40 210 --- yes 331 36.8 175 white-crystalline ---333 20 180 --- yes 334 15 180 --- ___ llZ~)6 7'1 Photomicrographs of Examples 322, 326, 328, 330 and 333 are illustrated in Figs. 6 through 10, respectively (at 1325X, 1550X, 1620X, 1450X, and 1250X amplification, respect-ively). me extreme foliage of the 10% polymer microporous polymer is shown by Fig. 6, yet the microcellular structure is still maintained. These Figures illustrate the decreasing cell size as the amount of polymer is increased~ However, the microcellular structure is present in each example despite the small cell size.
EXAMPLES 335 to 337 me examples illustrate the polymer-compatible liquid concentration range useful for the formation of a homogeneous porous polymer intermediate from polypropylene and diphenyl-ether. In each example the intermediate was about 0.5 inch in depth and about 2.5 inches in diameter. In addition, as indi-cated, thin ~ilms were also made. m e PP was a utilized in previous examples.
me details of preparation and any physical charac-teristics noted are set forth in Table XX:
TABLE XX
Ex. ~o. %/O Liq. C. min Film 335 90 200 yes 336 80 200 yes 337 70 200 yes Photomicrographs of the porous polymer of Examples 35, 336 and 337 are illustrated in Fig. 11 (2000X amplifica-tion), 12 (2059X amplification and 13 (1950X amplification).
me Figures illustrate that as the polymer concentration is increased, the pore size decreases, Fig. 11 illustrates the smooth cell walls, while Figs. 12 and 13 illustrate the cells and connecting pores. In each of the Figures, the micro-)6 71 cellular structure is present.
EXAMPLES 338 to 346 mese examples illustrate the polymer-compatible li-quid concentration range useful for the formation of a homo-geneous porous polymer intermediate from styrene-butadiene rubber and N,N-bis(2-hydroxyethyl) tallowamine. In each ex-ample the intermediate was about 0.5 inch in depth and 2.5 inches in diameter. In addition, as indicated, thin films were made. The SBR was as utilized in previous Examples.
The details of preparation and any physical charac-teristics noted are set forth in Table XXI:
TABLE XXI
Ex. ~o. % Liq. C. Remarks min Film 338 90 200 weak, beyond the yes upper liquid limit 339 80 195 rubbery yes 340 75 195 rubbery yes 341 70 195 rubbery yes 342 60 200 rubbery yes 343 50 not reported rubbery yes 344 40 not reported rubbery yes 345 30 not reported rubbery yes 346 20 not reported yes Photomicrographs for the styrene-butadiene rubber microporous polymer of Examples 339 and 340 are illustrated in Figs. 20 (2550X amplification) and 21 (2575X amplification).
The Figures illustrate the microcellular structure of the microporous polymers. Fig. 21 also shows the presence of spherical polymer deposits on the cell walls.
EXAMPLES 347 to 352 Examples 347 through 352 illustrate the polymer-~0~

compatible liquid concentration range useful for the formation of a homogeneous porous polymer intermediate from styrene-butadiene rubber and decanol. In each Example the interme-diate was about 0.5 inch in depth and 2.5 inches in diameter.
In addition, as indicated, thin films were made. The SBR was as utilized in previous examples.
The details of preparation and any physical charac-teristics noted are set forth in Table XXII:
TABLE XXII
Ex. No. /O Liq. Temp., C. Remarks Thin Film 347 90not reported beyond upper liquid limit, not operable ---348 80 190 rubbery yes 349 70 190 rubbery yes 350 60 190 rubbery yes 351 50 190 rubbery yes 352 40not reported rubbery ---TABLE XXIII
Ex. ~o. /O Liq. C. Remarks 353 80 not reported ---356 50 200-210 ~--EXAMPLES 357 to 361 Examples 357 through 361 illustrate the polymer-com-patible liquid concentration range useful for the formation of a homogeneous porous polymer intermediate from a "Surlyn" resin as utilized in previous Examples and N,N-bis(hydroxyethyl) tallowamine. In each Example the intermediate was about 0.5 inch in depth and 2.5 inches in diameter. In addition, as ~Z~)6 fl indicated, thin films were made.
The details of preparation and any physical charac-teristics noted are set forth in Table XXIV:
TABLE XXIV
Ex. No. % Liq. C. Ihin Films 357 70 190-195 yes 358 60 190 yes 359 50 not reported yes 360 40 not reported yes 361 30 not reported yes _ EXAMPLES 362 to 370 These examples illustrate the polymer-compatible li-quid concentration range useful for the formation of a homo-geneous porous polymer intermediate from a "Surlyn" resin as utilized in previous Examples and diphenylether. In each ex-ample the intermediate was about 0.5 inch in depth and about 2.5 inches in diameter. In addition, as indicated, thin films were made.
The details of preparation and any physical charac-teristics noted are set forth in Table XXV:

TABLE XXV
Ex. No. % Liq. C. Thin Films 362 90 207 yes 363 80 190 yes 364 70 200 yes 365 60 185 yes 366 50 not reported yes 367 40 not reported ---368 30 not reported ---369 20 not r~ported ---370 10 not reported ---EXAMPLES 371 to 379 Examples 371 through 379 illustrate the polymer-compa-tible liquid concentration range useful for the formation of a homogeneous porous polymer intermediate from a "Surlyn" resin as utilized in previous Examples and dibutylphthalate. In each Example the intermediate was about 0.5 inch in depth and about 2.5 inches in diameter.
The details of preparation and any physical charac-teristics noted are set forth in Table XXVI:
TABLE XXVI
Ex. No. /O Liq. C. Remarks 372 80 208 ~--373 70 195 ___ 376 40 not reported ---377 30 not reported ---378 20 not reported ---379 10 not reported ---EXAMPLES 380 to 384 Examples 380 to 384 are reproductions of various prior art compositions which are shown to have a physical structure different from that of the present invention.

A porous polymer was prepared in accordance with the process of Example 1 of U.S. Patent ~o. 3,378,507, as modified to obtain a product with some physical integrity and to uti-lize a soap as the water-soluble anionic surfactant, in place of sodium bis(2-ethylhexyl) sulfosuccinate.

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In a Brabender-Plasti-Corder internally heated blender, 33 1/2 parts by weight of Exxon Chemical Corporation type LD 606 polyethylene and 66 Z/3 part of Ivory* soap flakes were mixed at a machine temperature of about 350F., until a homogeneous blend was formed. The material was then compression molded with a rubber type mold having a 2.5 inch by 5.0 inch cavity of a depth of 20 mils., at a temperature of about 350F. and a pres-sure of 36,000 pounds per square inch. The resulting sample was continuously washed for about three days in a slow flowing stream of tap water and then sequentially washed by immersion in eight distilled water baths, each for a period of about one hour. The resulting sample still retained some soap and had poor handling properties.
Figs. 47 and 48 are photomicrographs of the product of Example 380, at 195X and 2,000X amplification, respectively.
It is apparent that the product is relatively non-uniform polymeric structure having neither distinct cellular cavities not interconnecting pores_ A porous polymer was prepared in accordance with the process of Example 2, sample D, of U.S. Patent ~o. 3,378,507, as modified to obtain a sample having some handling strength.
In a Brabender-Plasti-Corder internally heated blender, 75 parts of Ivory soap flakes and 25 parts of Exxon Chemical Corporation type LD 606 polyethylene were mixed at a machine temperature of about 350F. and a sample temperature of about 330F. until a homogeneous blend was formed. The material was then injection-molded in a one-ounce Watson-Stillman injection molding machine having a mold cavity diameter of two inches and a depth of 20 mils. The resulting sample was continuously washed for about three days in a slowly flowing stream of tap * Trade Mark ~Z(~6 ~1 water and then sequentially washed by immersion in eight dis-tilled water baths, each for a period of about one hour. The resulting sample still retained some soap.
Figs. 45 and 46 are photomicrographs of the product of Example 381, at 240X and 2400X amplification, respectively.
The product of this example does not have the typical cellular structure of the present invention, as is apparent from the photomicrographs.

In accordance with the process of Example 3, sample A, of U.S. Patent No. 3,378,507, a porous polymer was prepared.
In a Brabender-Plasti-Corder internally heated blender, 25 parts of Novamont Corporation type F300 8Nl9 polypropylene and 75 parts of Ivory soap flakes were mixed at a machine tem-perature of about 330F. until a homogeneous blend was formed.
The material was then compression molded with a rubber type mold. me resulting sample was found to have very little strength. A portion of the resulting sample was continuously washed for about three days in a slowly flowing stream of tap water and then sequentially washed by immersion in eight dis-tilled water baths, each for a period of about one hour. me washed product was found to have extremely poor handling cha-racteristics.
Figs. 51 and 52 are photomicrographs of the product of Example 382 at 206X and 2000X amplification, respectively. m e photomicrographs show that the product does not have the cel-lular structure of the present invention.
EX~MPLE 383 m e process of Example 3, sample A, of U.S. Patent No. 3,378,507 was modified to obtain a product having improved handling strength.

llZ6~ii 7~

On an open two roll rubber mill, manufactured by the Bolling Company, 25 parts of Novamont Corporation type F300 8Nl9 polypropylene and 75 parts of Ivory soap flakes were mixed for about ten minutes at a temperature of about 350F.
until a homogeneous blend was formed. The material was then injection molded with a one-ounce Watson-Stillman injection molding machine having a mold cavity diameter of twc inches and a depth of 20 mils. The resulting sample was continuously washed for about three days in a slowly flowing stream of tap water and then sequentially washed by immersion in eight distilled water baths, each for a period of about one hour.
me resulting sample still retained some soap. me resulting product was found to be stronger than the product of Example 382.
Figs. 49 and 50 are photomicrographs of the product of Example 383 at 195X and 2000X amplification, respectively. The irregular shapes shown by the photomicrographs are readily distinguishable from the structure of the present invention.

A porous polymer was prepared in accordance with Exam-ple II of U.S. Patent No. 3,310,505, as modified to obtain a more homogeneous mixing of the materials.
In a Brabender-Plasti-Corder internally heated blender, 40 parts of Exxon Chemical Corporation type LD 606 polyethylene and 60 parts of Rohm and Haas Corporation polymethylmethacry-late were mixed, for about 10 minutes, at a machine tempera-ture of about 350F. until a homogeneous blend was formed. The material was then sheeted on a cold mill and subsequently com-pression molded using a heated four-inch circular die with a depth of 20 mils. and 30 tons of pressure for about ten minutes. The resulting composition was extracted for 48 hours with acetone in a large Soxlet extractor.

~iZ~ 7i Figs. 53 and 54 are photomicrographs of the product of Example 384 at 205X and 2000X amplification, respectively.
The non-uniform structure shown by the photomicrographs is easily distinguished from the uniform structure of the present invention.
PHYSICAL CHARACTERIZATION OF
EXAMPLES 225 and 358 To obtain a quantitative understanding of the homoge-neous structure of the present invention, certain samples of the microporous material and certain prior art samples were analyzed on an Aminco mercury intrusion porosimeter. Figs.
30 and 31 are mercury intrusion curves of the one-half inch block of Example 225 which was made with 25 per cent polypropyl-ene and 75 per cent N,N-bis(2-hydroxyethyl) tallowamine, and Fig. 32 is a mercury intrusion curve of the 6 inch block of Example 225. All mercury intrusion curves are shown on a semi-log graph with the equivalent pore sizes shown on the log scale abscissa. Figs. 30 through 32 show the typical narrow distribution of pore sizes in the composition of the instant invention. It was determined that the one-half inch sample of Example 225 has a void space of about 76 per cent and an average pore size of about 0.5 micron and the 6 inch block has a void space of about 72 per cent and an average pore size of about 0.6 micron.
Fig. 33 is a mercury intrusion curve of the product of Example 358 which was made with 40 per cent polypropylene and 60 per cent N,N-bis(2-hydroxyethyl) tallowamine. Fig. 33 shows that the sample has the typical narrow pore size distri-bution. It was determined that the sample had a void space of about 60 per cent and an average pore size of about 0.15 micron.

_99_ It is readily apparent that the compositions of this invention have such pore size distributions that at least 80 per cent of the pores present in the composition fall within no more than one decade on the abscissa of the mercury intru-sion curve. The pore size distribution of the composition may thus be characterized as "narrow".

PHYSICAL CHARACTERIZATIO~ OF
PRIOR ART COMMERCIAL COMPOSITIO~S

The composition of this example is commercially avail-able Celgard 3501 microporous polypropylene, manufactured by Celanese. Fig. 34 is a mercury intrusion curve of the sample showing a large population of pores in the range of 70 to 0.3 microns. me sample was determined to have a void space of about 35 per cent and an average pore size of about 0.15 microns.

The composition of this example is commercially avail-able A-20 microporous polyvinylchloride, manufactured by Ame-race~ Fig. 35 is a mercury intrusion curve of the sample andshows a very broad pore size distribution. me sample was determined to have a void space of about 75 per cent and an average pore size of about 0.16 microns.

me composition of this example is commercially avail-able A-30 microporous polyvinylchloride and manufactured by Amerace. Fig. 36 is a mercury intrusion curve of the sample and shows a very wide pore size distribution. me sample was determined to have a void space of about 80 percent and an average pore size of about 0.2 microns.

The composition of this example is commercially avail-:llZ~

able Porex microporous polypropylene. Fig. 37 is a mercuryintrusion curve of the sample showing a very broad distribu-tion of extremely small cells as well as a distribution of very large cells. The sample was determined to have a void space of about 12 per cent and an average pore size of about one micron.

The composition of this example is commercially avail-able Millipore BDWP 29300 microporous polyvinylchloride. Fig.
38 is a mercury intrusion curve of the sample showing a rela-tively narrow distribution in the range of 0.5 to 2 microns as well as a number of cells smaller than about 0.5 micron. The sample was determined to have a void space of about 72 per cent and an average pore size of about 1.5 microns.

The composition of this example is commercially avail-able Metricel TCM-200 microporous cellulose triacetate manufac-tured by Gelman. Fig. 39 is a mercury intrusion curve of the sample showing a broad pore size distribution up to about 0.1 micron. The sample was determined to have a void space of about 82 per cent and an average pore size of about 0.2 micron.

The composition of this example is commercially avail~
able Acropor WA microporous acrylonitrile-polyvinylchloride co-polymer manufactured by Gelman. Fig. 40 is a mercury intrusion curve of the sample showing a broad pore size distribution. The sample was determined to have a void space of about 64 per cent and an average pore size of about 1.5 microns.
PHYSICAL CHARACTERIZATION OF PRIOR AR
EXAMPLES 380 to 384 The products of prior art Examples 380 to 384 were also analyzed by mercury intrusion. Figs. 41-43 are mercury in-trusion curves showing the broad pore size distribution of the products of Examples 381, 380, and 383, respectively. Fig. 44 is a mercury intrusion curve for the product of Example 384, showing a population of pores in the range of 45 to 80 microns as well as a number of extremely small pores. The products of Examples 380, 381, 383, and 384 were determined to have void spaces of about 54, 46, 54, and 29 per cent and average pore sizes of about 0.8, 1.1, 0.56, and 70 microns, respectively.
EXAMPLES 392 to 399 These examples illustrate the polymer/compatible liquid concentration range useful for the formation of homogeneous porous polymer intermediates from polymethylmethacrylate and 1,4-butane diol using the standard preparation procedure. In each example the intermediate formed was about 0.5 inches in depth and about 2.5 inches in diameter. The polymethylmetha-crylate was supplied by Rohm and Haas under the designation Plexiglas Acrylic Plastic Molding Powder, lot number 386,491.
The details of preparation are set forth in Table XXVII:
TABLE XXVII
EXAMPLE NO. % LIQUID TEMP., C.

30The 1,4-butanediol was removed from the product of Example 395 and the resultant structure was determined to be `7~

the cellular structure of the present invention, as may be seen from Fig. 61 which shows the microporous product at 5000X am-plification. The sam~ polymer/liquid system as that of Example 394 was also cooled at rates up to 4000C per minute and still produced the cellular structure of the present invention.

The porous polymer intermediate was prepared using the standard preparation procedure and heating 30 per cent poly-methylmethacrylate, as utilized in the previous examples, and 70 per cent lauric acid to 175C and cooling to form the porous polymer intermediate. The lauric acid was removed from the resultant intermediate to form the microporous cellular struc-ture of the present invention.

The porous polymer intermediate was prepared using the standard preparation procedure and heating 30 per cent Nylon

11, supplied by Aldrich Chemical Company, and 70 per cent ethyl-ene carbonate to a temperature of 218C and then cooling the resultant solution to form the porous polymer intermediate.
me ethylene carbonate was removed from the intermediate and the resultant microporous polymer was determined to have the cellular structure of the present invention.
EXA~PLE 402 The porous polymer intermediate was prepared using the standard preparation procedure and heating 30 per cent Nylon 11, as utilized in the previous example, and 70 per cent 1,2-propylene carbonate was removed from the intermediate and the resultant microporous polymer was determined to have the cellular structure of the present invention.

Examples 403-422 demonstrate the formation of the ~ 6;71 porous polymer intermediates from polymer/liquid systems con-taining various amounts of Nylon 11, as utilized in previous Examples, and tetramethylene sulfone, supplied by Shell under the designation Sul~one W, and containing approximately 2.5 per cent water. The various concentrations were cooled at various rates and from various solution temperatures, as indi-cated in Table XXVIII which also demonstrates that increased cooling rates and increased concentration of the polymer cause the resulting cell sizes to decrease, in general.
TABLE XXVIII

Cooling Rate Cell Size Ex. ~O- o/O Liq. T C.~C/Min. (Microns) 407 80 198 80 5~5 410 70 200 40 6.5 411 70 200 80 6.5 412 60 205 5 5.
413 60 205 20 4.5 415 60 205 80 3,5 417 50 210 40 1.5 11;~06 7~

The foregoing Table XXVIII also demonstrates that at concentrations from 40 per cent to 10 per cent liquid, there is no resulting visible porosity, for the system cooled at 20C
per minute. Such results are entirely anticipated as may be seen by referring to Fig. 62 which shows the melt curve for the ~ylon ll/tetramethylene Sulfone concentration range, as well as the crystallization curves at the various rates of cooling. It is apparent from FigO 62 that at 20C/minute cooling rate, the system containing 40% liquid does not fall within the substan-tially flat portion of the crystallization curve and thuswould not be expected to form the desired micropGrous structure.
Fig. 63 is a photomicrograph at 2000X amplification of Example 409 showing the typical cellular structure of Examples 403-418.
EX~MPLE 423 me porous polymer intermediate was prepared by using the standard preparation procedure and heating 30 per cent poly-carbonate supplied by General Electric under the designation Lexan* and 70 per cent menthol to a temperature of 206C and cooling to form the porous polymer intermediate. m e menthol was extracted and a cellular microporous structure resulted as shown in Fig. 64, which is a photomicrograph of the product of this Example at 2000X amplification.

m is example demonstrates the formation of the micro-porous cellular structure of the present invention from poly-2,6-dimethyl-1,4-phenylene oxide, supplied by Scientific Poly-mer Products, commonly referred to as polyphenylene oxide.
me homogeneous microporous polymer intermediate was made from 30 percent of said polyphenylene oxide and 70 percent N,N-bis-(2-hydroxyethyl) tallowamine which was heated to a solution * Trade Mark 7~L

temperature of 275C and the intermediate was formed using the standard preparation procedure. me liquid was removed from the intermediate and the cellular structure of the present invention resulted, as may be seen from Fig. 65 which is a photomicrograph of the product of this Example at 2000X am-plification.

This Example demonstrates the formation of the non-cellular product of this invention by cooling a homogeneous solution of 40 percent polypropylene, as utilized in the pre-vious Examples, and 60 percent dibutyl phthalate. The solu-tion was extruded onto a chilled belt at a thickness of about 10 mils and the cooling rate was in exce.ss of 2,400C. A
quantity of dispersol was applied to the surface of the belt at a point prior to the solution being extruded thereon. The li-quid was removed from the resultant film and a non-cellular microporous product resulted, as may be seen from Fig. 65 which is a photomicrograph of the product of this Example at 2000X amplification.
EXAMPLE 42_ This Example demonstrates the formation of the non-cellular product of this invention by cooling a homogeneous solution of 25 percent polypropylene, as utilized in previous examples, and 75 percent ~,N-bis(2-hydroxyethyl) tallowamine in the same manner as that of Example 425. The liquid was removed from the resultant film and a non-cellular microporous product resulted, as may be seen from Fig. 67 which is a photo-micrograph of the product of this Example at 2000X amplifica-tion.
m e products of Examples 425 and 426 were analyzed by mercury intrusion porosimetry and their respective intrusion ~106-0f~7~

curves are shown in Figs. 68 and 69. It is apparent that both products have generally narrow pore size distributions, but the product of Example 426 demonstratés a much narrower distri-bution than the product of Example 425. Thus, the product of Example 425 has a calculated S value of 24.4 whereas the pro-duct of Example 426 has a calculated S value of only 8.8. The average pore size of Example 425 is, however, very small, 0.096 microns, whereas the average pore size of the product of Exam-ple 426 is 0.589.
To quantitatively demonstrate the uniqueness o~ the cellular compositions of the present invention, a number of such microporous products were prepared in accordance with the standard preparation procedure and the details relating there-to are summarized in Examples 427-457 in Table XXIX. The products of said Examples were analyzed by mercury intrusion porosity to determine their respective average pore diameter and the S value and by scanning electron microscopy to deter-mine their average cell size, S. The result of such analysis are shown in Table XXX.

TABLE XXIX
Solution Ex. No. Polymer Liquid % Void Temp. C.

427 polypropylene N,N-bis(2-hydroxy-ethyl) tallowamine 75 180 428 polypropylene N,N-bis(2-hycroxy-ethyl) tallowamine 60 210 429 polypropylene diphenylether 90 200 430 polypropylene diphenylether 80 200 431 polypropylene diphenylether 70 200 432 polypropylene 1,8-diaminooctane 70 180 433 polypropylene phenylsalicylate 70 240 434 polypropylene 4-bromodiphenylether 70 200 435 polypropylene tetrabromoethane 90 180 TABLE XXIX (continued) Solution Ex. No. Polymer Liquid/O Void Temp. C
436 polypropylene N-octyldiethanol-amine 75 -~~
437 polypropylene N-hexyldiethanol-amine 75 260 438polypropylene salicylaldehyde 70 185 439low density polyethylene hexanoic acid 70 190 440 low density polyethylene l-octanol 70 178 441 low density polyethylene dibutyl sebacate 70 238 442 low density polyethylene Phosclere EC-53 70 191 443 low density polyethylene dicapryl adipate 70 204 444 low density polyethylene diisooctyl phthalate 70 204 445 low density polyethylene dibutyl phthalate 70 290 446 high density N,N-bis(2-hydroxy polyethylene ethyl) tallowamine 80 250 447 polystyrene l-dodecanol 75 220 448 polystyrene 1,3-bis(4-piperidine~
propane 70 186 449 polystyrene diphenylamine 70 235 450 polystyrene N-hexyldiethanol-amine 75 260 451 polystyrene Phosclere P315C 70 270 452 polymethyl-methacrylate 1,4-butanediol 70 ---453 polymethyl-methacrylate 1,4-butanediol 85 ---454 Surlyn diphenylether 70185-207 455 Surlyn dibutyl phthalate 70 195 456 Noryl N,N-bis(2-hydroxy-ethyl) tallowamine 75 250 457 Nylon 11ethylene carbonate 70 ---0~7~

TABLE XXX
EX. ~o. _ P C/P S loq C/P loq S/C
427 5.0 0.520 9.6 2.86 0.982 -0.243 428 3.18 0.112 28.4 5.0 1.45 0.197 429 22.5 11.6 1.94 4.52 0.288 -0.697 430 6.49 0.285 22.8 27.1 1.36 0.621 431 6.72 0.136 49.4 7.01 1.69 0.0183 432 13.0 0.498 26.1 2.36 1.42 -0.741 433 13.8 0.272 50.7 4.29 1.71 -0.507 434 3.35 0.137 24.5 5.25 1.39 0.195 435 15.4 0.804 19.2 5.13 1.28 -0.477 436 16.6 0.850 19.5 2.52 1.29 -0.819 437 20.0 0.631 31.7 2.51 1.50 -0.901 438 7.9 0.105 75.2 3.22 1.88 -0.390 439 7.5 1.16 6.47 8.62 0.811 0.0604 440 - 6.8 1.00 6.8 3.53 0.833 0.285 441 5.85 0.636 9.20 6.07 0.964 0.0160 442 3.40 0.512 6.64 5.30 0.822 0.193 443 5.0 0.871 5.74 8.21 0.759 0.215 444 4.75 0.631 7.53 3.54 0.877 -0.128 445 7.8 1.18 6.61 3.82 0.820 -0.310 446 34.5 0.696 49.6 4.34 1.70 -0.900 447 28.2 1.88 1~ .0 3.40 1.18 -0.919 448 1.08 0.0737 14.7 2.87 1.17 0.424 449 6.65 0.631 10.5 63.5 1.02 0.980 450 7.4 0.164 45.1 3.74 1.65 -0.296 451 1.4 0.151 9.27 2.26 0.967 0.208 452 9.2 0.201 45.8 3.68 1.66 -0.398 453 114 10.3 11.1 5.19 1.05 -1.34 454 6.8 0.631 10.8 2.13 1.03 -0.504 455 5.6 0.769 7.28 2.09 0.862 -0.428 456 19.0 0.179 106 2.74 2.03 -0.841 457 5.8 0.372 15.6 7.56 l.lg 0.112 TABLE XXXI
EX. No. Prior Art Description Polymer Type 458 Celgard 3501 polypropylene 459 Amerace A-30 polyvinylchloride 460 Porex polypropylene 461 Millipore EG cellulosic 462 Metricel GA-8 cellulosic 463 Sartorius SM 12807 polyvinylchloride 464 Millipore HAWP cellulosic 10 465 Millipore G5WP 04700 cellulosic 466 Millipore VMWP 04700 cellulosic 467 Amicon 5UM05 cellulosic 468 Celgard 2400 polypropylene 469 Millipore SMWP 04700 polyvinylchloride 470 Celgard 2400 polypropylene 471 Product of Example 381 polyethylene 472 Product of Example 380 polyethylene 473 Product of Example 383 polypropylene 474 Product of Example 384 polyethylene ~lZ06'7~

TABLE XXXII
Ex. No. C S loq S/C
458 0.04* 2.32 1.76 459 0.3 138 2.66 460 186 2.41 -1.89 461 0.2* 26.3 1.85 462 0.2* 9.14 1.66 463 0.2* 31.5 2.2 464 0.8* 2.94 0.565 10 465 0.22* 1.64 0.872 466 0.05* 5.37 2.03 467 2.10** 61.8 1.79 468 0.02* 5.08 2.40 469 5* 1.55 -0.509 470 0.04* 5.64 2.15 471 1.1** 11.5 1.019 472 0.8** 17.5 1.34 473 0.56 16.8 1.477 474 70 1.34 -1.718 20 * From company product information ** From mercury intrusion me data contained in Tables XXIX through XXXII is sum-marized in Fig. 70 which is a plot of the log S/C vs. loq C/P.
From Fig. 70 it is apparent that the cellular structure of the present invention may be defined at having a log C/P of from about 0.2 to about 2.4 and a log S/C of from about -1.4 to about 1.0, and more usually said polymer will have a log C/P
of from about 0.6 to about 2.2 and a log S/C of from about -0.6 to about 0.4.
Thus, as has been seen, the present invention provides a facile method for preparing microporous polymers any synthetic thermoplastic polymer in widely varying thicknesses and shapes.

The microporous polymers may possess a unique microcellular configuration and are in any event characterized by pore dia-meters with relatively narrow size distribution. These struc-tures are formed by first selecting a liquid that is compatible with a polymer, i.e. - forms a homogeneous solution with the polymer and can be removed from the polymer after cooling and then selecting the amount of the liquid and carrying out the cooling of the solution in a fashion which insures that the desired microporous polymer configuration will result.
As can be also seen, the present invention also provides microporous polymer products which contain relatively large amounts of functionally useful liquids such as a polymer addi-tive and behave as a solid. These products may be advantageous-ly utilized in a variety of applications such as, for example, in masterbatching.
This application is a division of Canadian Patent Application Ser. No. 285,080 filed on August 19, 1977.

Claims (15)

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:

1. A method of preparing a relatively homogeneous, iso-tropic, three-dimensional microporous polymer structure com-prising heating a mixture of a synthetic thermoplastic polymer selected from the group consisting of olefinic polymers, con-densation polymers, oxidation polymers, and blends thereof, and a compatible liquid to a temperature and for a time suf-ficient to form a homogeneous solution, allowing said solu-tion to assume a desired shape, cooling said solution in said desired shape at a rate and to a temperature sufficient to initiate thermodynamic, non-equilibrium liquid-liquid phase separation, continuing cooling to form a solid and removing at least a substantial portion of the liquid from the result-ing solid to form the microporous polymer structure.

2. me method of claim 1 wherein essentially all of the liquid is removed.

3. The method of claim 1 wherein said mixture com-prises from about 10 to about 90% by weight of the liquid.

4. The method of claim 1 wherein the homogeneous solu-tion is cast into a film as it is cooled.

5. The method of claim 1 wherein the homogeneous solu-tion is cast into the form of a block as it is cooled.

6. The method of claim 5 wherein the block has a thickness up to about 2 1/2 inches.

7. The method of claim 1 wherein the homogeneous solu-tion, as it is cooled, is cast onto a substrate which forms an essentially non-cellular skin on the surface of the micro-porous polymer in contact with said substrate.

8. The method of claim 7 wherein the skin formed is relatively impervious to liquids

9. The method of claim 1 wherein the polymer is a non-acrylic polyolefin.

10. The method of claim 1 wherein the polymer is select-ed from the group consisting of low density polyethylene, high density polyethylene, polypropylene, polystyrene, poly-vinylchloride, acrylonitrile-butadiene-styrene terpolymers, styrene-acrylonitrile copolymers, styrene butadiene copoly-mers, poly (4-methyl-pentene-1), polybutylene, polyvinylidene chloride, polyvinyl butyral, chlorinated polyethylene, ethylene-vinyl acetate copolymers, polyvinyl acetate and poly-vinyl alcohol.

11. The method of claim 1 wherein the polymer is an acrylic polyolefin.

12. The method of claim 1 wherein the polymer is select-ed from the group consisting of polymethyl-methacrylate, poly-methyl-acrylate, ethylene-acrylic acid copolymers, and ethyl-ene-acrylic acid metal salt copolymers.

13. The method of claim 1 wherein the polymer is an oxidation polymer.

14. The method of claim 1 wherein the polymer is poly-phenylene oxide.

15. The method of claim 1 wherein the polymer is select-ed from the group consisting of polyethylene terephthalate, polybutylene terephthalate, Nylon 6, Nylon 11, Nylon 13, Nylon 66, polycarbonates and polysulfone.