BE886829A - TUBULAR SHEETS FOR PERMEATION APPARATUS - Google Patents

Description

       

  The present invention relates to permeation apparatuses containing hollow fiber membranes and more particularly relates to permeation apparatuses comprising formed tubular sheets

  
from a liquid resin composition containing a polyglycidyl resin and a finely divided filler.

  
Permeation apparatuses comprising hollow fiber membranes are often advantageous because of the high ratio that can be obtained with respect to the specific surface area of the membranes per unit volume of the permeation apparatus. As a result, permeation devices with hollow fiber membranes can be sufficiently

  
compact to find desirable applications in many fluid separation operations, for example gas / gas, gas / liquid and liquid / liquid separations (including dissolved solids in

  
liquids).

  
In these permeation apparatus; at least one end of each of the hollow fiber membranes is usually wrapped in a tubular sheet, while the conduits of the hollow fiber membranes extend through the tubular sheet in a fluid communication relationship. An object of this tubular sheet is to secure the hollow fiber membranes in a substantially fluid tight relationship within this sheet. This tubular sheet can be fixed in a substantially fluid-tight relationship in the permeation apparatus so that the fluid does not pass from one exterior side or from the conduit side to the other side of a hollow fiber membrane., except through the wall of this membrane.

  
Even small leaks around the tubular sheet can dramatically affect performance

  
  <EMI ID = 1.1>

  
bypassing the permeation can pass, via these leaks, to the side by which the permeate leaves the hollow fiber membranes, thereby reducing the selectivity that the permeation device can provide during separation. The purpose of this tubular sheet is also to form, for the flow of the fluid, a sufficiently resistant stop element so that, under the operating conditions, this tubular sheet does not undergo rupture or does not lose its integrity. otherwise, which would allow the fluid to pass through this tubular sheet.

   Consequently, this tubular sheet most often has a high thickness in order to ensure a sealing relationship. tee with fluids with hollow fiber membranes and also so that the tubular sheet can resist pressure differences to which it may be subjected during an operation. separation envisaged.

  
Generally, tubular sheets are made using a liquid resinous composition in which the resin can be natural or synthetic and which

  
  <EMI ID = 2.1>

  
then assembled into a bundle; similarly, this resin can also be cast in the form of a liquid around a bundle previously assembled and made up of hollow fiber membranes, this resin then being solidified, for example, by hardening. Many exceptional considerations exist in the choice of a suitable liquid resin composition for the formation of tubular sheets. For example, it is usually desirable to have the following characteristics:

  
1. Before and after solidification, the resin must adhere sufficiently to the hollow fiber membrane in order to achieve the desired fluid tightness relationship between the tubular sheet

  
and hollow fiber membranes;

  
2. the solidified resin must have sufficient strength and integrity to resist <EMI ID = 3.1>

  
worms of tabular sheet during the planned separation operations;

  
3. the composition, liquid resinous must undergo little

  
  <EMI ID = 4.1>

  
does not create exaggerated internal tensions inside the tubular sheet and that the solidified resin does not separate from the hollow fiber membranes or does not generate, in the latter, tensions altering the integrity of these membranes;

  
4. the liquid resinous composition must not dissolve in an exaggerated manner or must not otherwise alter the material of the hollow fiber membranes;

  
  <EMI ID = 5.1>

  
ment free of internal tensions such as those which can be caused by temperature differences during solidification. in particular, during the hardening of the liquid resinous composition. (The trend

  
at the appearance of these internal tensions increases in tubular sheets comprising at least one zone which does not comprise a hollow fiber membrane and which, therefore, may have, vis-à-vis an area containing hollow fiber membranes, different characteristics with regard to the release, absorption or transfer of heat, as well as possibly different characteristics with regard to

  
  <EMI ID = 6.1>

  
liquids containing resins yes polymerize (harden) during or after solidification, the heat given off Possibly during the polymerization must not give rise, in the tubular sheet, to temperatures altering the mem. branes with hollow fibers, while the possible heat- <EMI ID = 7.1>

  
The polymerization tee must not alter the hollow fiber membranes;

  
7. in particular, when the tubular sheet is cast around a previously assembled bundle made up of hollow fiber membranes, the viscosity of the liquid resinous composition must be sufficient.

  
  <EMI ID = 8.1>

  
through this beam;

  
8. the liquid resinous composition must not be drawn in excessively between the hollow fiber membranes by capillary action (which will be referred to below as "wicking effect"); moreover, any wicking effect which may appear must be relatively uniform over the cross section of the bundle of hollow fiber membranes;

  
9. the tubular sheet must have sufficient resistance to chemicals so as to maintain adequate resistance and dimensional stability during the envisaged separation operations;

  
10. the manufacture of the tubular sheet must be relatively devoid of complexity and one must avoid having to use complex equipment, while this manufacture must be able to be carried out with a minimum residence time, as well as with a duration, a minimal experience and skilled labor;

  
11. the solidified liquid resinous composition must be capable of being cut or shaped, for example, so as to expose the conduits of the hollow fiber membranes or to adapt the tubular sheet for the assembly of the permeation apparatus; and

  
12. the components of the liquid resinous composition must not present any exaggerated risk of toxicity during

  
of the formulation of the liquid resin, during the preparation of the tubular sheet or after the production thereof.

  
A wide variety of resins have been proposed for making tubular sheets for hollow fiber membranes. For example, in US Patent No. 3,499,062 granted on March 3, [deg.]

  
  <EMI ID = 9.1>

  
solders, cements, waxes &#65533; adhesives, natural resins and synthetic resins. U.S. Patent No. 3,422,008 granted on January 14, 1969 to McLain describes the use of epoxy resins to form tubular sheets and also suggests that resins from

  
  <EMI ID = 10.1>

  
synthetic, thermosetting rubbers and acrylic resins may also be suitable. Among

  
  <EMI ID = 11.1>

  
edged to form tubular sheets, there are urethane resins, silicone resins, polysulfides, acetals; cellulosic resins, fluorocarbons &#65533; vinyl resins, styrenes,

  
polyethylene and polypropylene (see, for example, US Patents No. [deg.] 3,760,949 granted September 25, 1973; 4,049,765 granted September 20, 1977 and 4,138,460 granted March 6 February 1979).

  
Epoxy resins are the most preferred resins for forming tubular sheets. By

  
  <EMI ID = 12.1>
3,728,425 granted on April 17, 1973 in the name of Schrader, describes the use of polyepoxides for the manufacture of tubular sheets intended for permeation apparatus. In this patent, it is suggested that the <EMI ID = 13.1>

  
polyhydric phenols such as resorcinol, catechol, hydroquinone, phloroglucinol., 2,2-bis-

  
  <EMI ID = 14.1>

  
nyl) butane, 4,4'-dihydroxyphenyl-phenylsulfone, as well as the condensation products of phenol / formaldehyde (for the manufacture of novolak resins). Most often, the epoxy resin described specifically by Schrader comprises a diglycidyl ether of bisphenol A.

  
Schrader's resinous composition also contains an aromatic amine as a hardening agent and a weakening agent.

  
  <EMI ID = 15.1>

  
100 parts of resin) of a thixotropic agent apparently intended to reduce the wicking effect, while nevertheless permitting the penetration of the resinous composition into a bundle of fibers. In Schrader's patent it is stated that colloidal silica ("Cab-0-Sil") is a useful thixotropic agent and it is suggested that a variety of other thixotropic agents such as clays, organic modified clays, organic modified silicas, as well as chemical derivatives of castor oil. Schrader

  
  <EMI ID = 16.1>

  
Reactive fluids of plasticizers, bonding agents and curing accelerators may be optional ingredients.

  
Although there are various proposals suggesting materials for tubular sheets for permeation apparatus containing hollow fiber membranes, in many cases these materials may lack one or more desirable properties such as product resistance chemical, absence of internal tensions, ease of manufacture, absence of intolerable risks of toxicity, absence of excessively high curing temperatures, etc. As a general rule, the yield required from a tubular sheet will depend on the operating conditions expected from the permeation apparatus. It has been found that permeation devices containing hollow fiber membranes can be used for desalting, ultra filtration and hemodialysis.

   In general, these separation operations create relatively moderate ambient environments, that is to say that the treated streams contain, in low concentrations, or even zero, fractions which can exert a harmful influence on the material of which the leaves are made. tubular
(for example, by loss of integrity or physical strength or by swelling). In addition, in operations such as hemodialysis, in which a small or even zero pressure difference is exerted across the tubular sheet, the physical resistance of the latter is not a primary factor. Consequently, there is greater freedom in the choice of the liquid resin composition intended for the manufacture of a tubular sheet.

   For example, aspects such as physical and chemical resistance can be sacrificed to prevent high temperatures from being reached or caused during curing, to obtain a liquid resin composition of desirable fluidity so that it can penetrate into a previously assembled bundle consisting of hollow fiber membranes, as well as to ensure good adhesion of the tubular sheet to these membranes. Even with permeation devices operating under relatively moderate conditions, great difficulty can still be encountered when it comes to obtaining a suitable liquid resin composition to form a tubular sheet.

   Obviously, these difficulties are accentuated when the tubular sheet must have a high physical strength and a high resistance to chemicals.

  
One of the problems which has been particularly troublesome in the manufacture of tubular sheets, in particular, in the manufacture of tubular sheets having high physical and chemical resistance, is the peak temperatures which can be reached during hardening of a liquid resinous composition by
- following exothermic curing reactions. For example, permeation devices having dimensions large enough to be of interest, for example, for gas / gas separations, may include <EMI ID = 17.1>

  
for example, at least 1 kg of liquid resin composition. Due to the generally poor thermal conductivity of these resins and also due to the highly exothermic nature of their curing reactions, these large amounts of liquid resin composition can generate temperatures high enough to damage the hollow fiber membranes and create tension thermal, for example, between an area comprising hollow fiber membranes and an area devoid of these membranes,

  
One method that can be adopted to avoid these high temperatures is to manufacture the tubular sheet, for example, by performing a series of

  
  <EMI ID = 18.1>

  
solidification taking place during each pouring before starting the next pouring. Since, during each casting, the volume is less than the total quantity required to manufacture the tubular sheet, the maximum temperature reached during each casting can be reduced. However, the interface between each casting can give rise to structural weaknesses and a considerable additional period of time may be necessary to perform several castings in order to manufacture a tubular sheet, compared to the time required for the manufacture of a tubular sheet in a single pour. Another method may be to cool the liquid resin composition during curing, for example,

  
by using a mold which can be cooled during the curing of the resin or by passing a coolant through the hollow fiber membranes during the curing of the resin. Consequently, this method may require certain complex equipment and processes. In addition, since liquid resinous compositions usually have poor heat transfer characteristics, cooling may give rise to exaggerated temperature differences in the liquid resinous composition during curing and therefore may result in a risk. the appearance of intolerable thermal stresses inside the tubular sheet; moreover, the colder areas of this tubular sheet during hardening may not acquire the desired degree of crosslinking.

   In addition, if the tubular sheet is kept at these lower temperatures, the time required to reach the desired degree of curing may be too long to be of commercial interest.

  
Fillers have generally been applied in epoxy resin formulations to reduce shrinkage, improve thermal shock resistance, dissipate heat, impart flame retardant properties and reduce cost prices (see, for example, Shimp, "Non-Fibrous Fillers for Epoxy Resins", Technical Bulletin 1667., published by "Celanese Coatings Company"

  
in 1967). In the patent of the United States of America n [deg.]
3,018,260 granted on January 23, 1962 in the name of Creighton Jr., it suggests formulations of epoxy resins for the manufacture of articles such as screws, tools, jigs, dies, molds, molded articles, models and tool holders. The formulations described in this patent contain finely divided metallic particles (for example, steel particles) in a volumetric ratio of 32 to
90% metal for 68 to 10% resin. One of the functions of these metallic particles is described in the colon 2, lines 21 to 29 of this patent:

  
"The polymerization of the resin gives rise to an exothermic reaction which is usually harmful in relatively thick articles, since the resin itself is a poor conductor of heat. However, in the high proportion in which they are used according to the "The metal particles serve as heat conductors from the internal parts of the mass to the surface thereof, thereby avoiding the detrimental effects of the heat of polymerization."

  
However, it is generally accepted that the fillers increase the viscosity of a liquid resinous composition. In addition, if the viscosity of the liquid resin composition is not high enough, the fillers can be deposited, even during hardening. Consequently, there may be a loss of uniformity in the hardening, as well as in the temperatures reached during the latter.

  
Much research has been done and an abundance of literature has been published on the general technology of epoxy resins (see, for example, Lee and Neville, Handbook of Epoxy Resins, 1967, "Epoxy

  
  <EMI ID = 19.1>

  
Epoxy sines have found widespread applications for coatings, bondings, electrical coatings, tools, flooring, castings, and the like. In many of these applications, it may be necessary for the epoxy resins to have different properties, for example, with respect to their physical strength, ease of processing, curing time, resistance to thermal deformation and the like. As a result, many epoxy resins and many different hardening agents are commercially available to meet the specific needs of a particular application.

   Although general properties and effects can be attributed to different epoxy resins, when looking for an epoxy resin suitable for a particular application, there may always be a need for ingenuity and this is particularly the case when it comes to relates to the choice of materials for tubular sheets in which very sensitive hollow fiber membranes can be used and for which high physical resistance and high resistance to chemicals may be required.

  
According to the present invention, permeation apparatuses are provided containing hollow fiber membranes and comprising tubular sheets containing a hardened solid resin and a filler. According to the present invention, tubular sheets containing fillers can be easily manufactured, in particular by manufacturing techniques consisting in casting a liquid resinous composition around a bundle previously assembled and made up of hollow fiber membranes. In addition, the filler can be used without exerting an intolerable harmful effect on the penetration of the liquid resin composition through

  
  <EMI ID = 20.1>

  
According to the present invention, the tubular sheet can advantageously be produced in a single casting in order to minimize the time required for its manufacture and the resin can be cured at an appropriate temperature without having to use complex equipment in order to minimize the curing time. and to achieve a maximum uniform degree of hardening throughout the tubular sheet., essentially without internal stresses.

  
The tubular sheets of the permeation apparatuses of the present invention comprise a solidified and hardened resinous composition formed from a liquid resinous composition containing a resin consisting of a preponderant amount by weight of a polyglycidyl resin, a composition of a hardening agent and a finely divided filler. According to the present invention, the resin has a viscosity of about 500 to 12,000 centipoise at room temperature and the polyglycidyl resin has a viscosity

  
  <EMI ID = 21.1>

  
cation contrary, all viscosities mentioned in this specification are Brookfield viscosities and they are determined at 25 [deg.] C. Preferably, the resin contains a predominant amount by weight of diglycidyl ether having an average molecular weight

  
  <EMI ID = 22.1>

  
an amount of diglycidyl ether having a weight average molecular weight of less than about 250.

  
In a preferred aspect of the invention, the curing agent composition contains at least two curing agents, a viscosity increasing agent and a solidifying agent. The viscosity increasing agent reacts quickly with the glycidyl groups contained in the resin and is provided in an amount sufficient to

  
  <EMI ID = 23.1>

  
which is so as to reduce the tendency of the filler to separate from the liquid resin composition, while the amount of this viscosity increasing agent is low enough not to raise the temperature of the liquid resin composition excessively by the exothermic curing reactions . The solidifying agent reacts more slowly with the glycidyl groups of the resin than the viscosity increasing agent. Consequently, the period during which the resin hardens, can be extended up to

  
t that the heat given off during exothermic hardening can be gradually dissipated and that the temperature prevailing throughout the tubular sheet during hardening can be relatively uniform in order to ensure a relatively uniform degree of hardening throughout the sheet tubular.

  
In addition, by allowing the heat produced by the exothermic curing reactions to dissipate, excessively high temperatures can be avoided during the curing of the resin.

  
According to the invention, the fillers that can be used to form the tubular sheets can consist of a wide variety of solid materials.

  
Frequently, suitable fillers have densities of about 1 to 10, preferably about 2 to 8 & by

  
  <EMI ID = 24.1>

  
fillers, there are, for example, inorganic fillers, organic modified inorganic fillers, as well as organic fillers. Among the inorganic fillers there are, for example, materials of the silica-based type such as silica, aluminum silicates (clays, feldspar, mica, etc.), sodium silicate, sodium borosilicate , talc, wollastonite; metals and metal oxides such as aluminum, aluminum oxide, iron, iron oxide, steel, copper, copper oxide, calcium oxide, carbon dioxide titanium, zinc, etc. ; inorganic salts such as barium sulfate, calcium carbonate, titanium sulfate, etc. ; and the like.

   Among the organic modified inorganic fillers there are, for example, inorganic fillers such as those described above with coupling agents containing organic groups. Usually, the coupling takes place via difunctional and trifunctional atoms such as oxygen atoms,

  
sulfur and nitrogen which are part of an organic fraction which may be an alkyl group, an alkenyl group, an aryl group (including an alkaryl group) or a heterocyclic group (the hetero atoms usually being at least one nitrogen atom, oxygen atom or sulfur atom). Frequently, the organic fraction contains one to about 50 carbon atoms, for example, about 1 to 20 carbon atoms. Silane fractions can also be useful and they can contain 1 to about 20 or 30 silicon atoms.

  
The organic fractions and the silane fractions can contain functional groups such as an amino group, a glycidyl group, a mercapto group, a hydroxy group, an acrylic group, a methacrylic group, etc.

  
Likewise, the coupling bond can be, for example, an ether or amine bond or else a phosphito, pyrophosphato, phosphato, carboxy, sulfonyl, amido, etc. bond. Coupling agents can frequently include glycols, glycerin, triethanolamine, glycidyltrialkoxysilanes, vinylsilane, dialkyl phosphites, etc. The organic fillers are usually solid resins, preferably thermosetting resins such as phenolic resins, epoxy resins, etc.

  
Preferably, the filler is in the state of particles as opposed to the fibrous state in order to minimize its effects on the viscosity of the liquid resinous composition and thus allow the latter to penetrate into hollow fiber membranes. Frequently; the average granularity and granulometry of the particles, as well as the ratio of specific surface area per unit volume of the filler contribute to ensuring the effect of the latter on the rheological properties of the liquid resinous composition. In many cases,

  
the average maximum cross section of the particles is less than about 200 microns, for example, about 1.5 to 150 microns and most often, about

  
2 to 100 microns, for example, about 2 to 50 microns.

  
In some cases, the average maximum particle size is about 2 to 30 microns. Usually, the filler is strongly free (for example, less than about 5% by weight, calculated on the total weight of the filler) of particles with a maximum cross section less than about 1 micron. Preferably, the filler should not have an excessively high specific surface so that the viscosity of the liquid resin composition is sufficiently reduced to allow penetration between the hollow fiber membranes. In general, the ratio between the specific surface and the weight of the fillers which can be used to produce the tubular sheets of the present invention is

  
  <EMI ID = 25.1>

  
  <EMI ID = 26.1>

  
about 0.1 to 2 or 2.5 m2 / g. The specific surface of a load can be determined by any suitable technique, for example, the analytical technique

  
  <EMI ID = 27.1>

  
for the determination of specific surfaces. Frequently, the aspect ratio of charges (based on the overall dimensions of the particulate charges) is from about 1: 1 to 50: 1 and sometimes from about 1: 1 to 20: 1.

  
The amount of filler used is at least sufficient to reduce the peak temperature reached during curing of the resin. The filler can reduce this peak temperature reached during curing of the resin: (1) by reducing the amount of resin required to form the tubular sheet, so that there are fewer glycidyl groups available for the reaction with evolution heat,

  
(2) by providing a mass intended to absorb the heat given off by the exothermic curing reactions and (3) by facilitating the transfer of heat

  
inside the tubular sheet. Very often,

  
  <EMI ID = 28.1>

  
at least about 10 or 15% by volume of the liquid resinous composition. The amount of the charge is before-

  
  <EMI ID = 29.1>

  
less than about 30% by volume of the liquid resinous composition in order to ensure adequate penetration thereof between the hollow fiber membranes. most

  
  <EMI ID = 30.1>

  
volume of the resin composition: use liquid.

  
The resin often represents at least about
30 and often, at least approximately. 40% by weight of the liquid resin composition. Excluding the charge,

  
  <EMI ID = 31.1>

  
about 85 to 95% of the liquid resin composition.

  
The viscosity of the resin can be about 500 to
12,000 centipoises at 25 [deg.] C and it is most often around 2,000 to 10,000 centipoises at 25 [deg.] C.

  
The resin contains a preponderant amount by weight of a polyglycidyl resin. The polyglycidic resin contains one or more diglycidyl compounds (including preplycidyl-terminated prepolymers). Likewise, the polyglycidyl resin may optionally contain trifunctional or higher functionality glycidyl compounds. Triglycidyls and compounds of higher functionality (eg, novolak resins) are generally not necessary to give the tubular sheets advantageous properties in terms of physical and chemical resistance, since as well the hardening agent based on imidazole very often ensures crosslinking. adequate to obtain the desired properties.

   However, when used, triglycidyl compounds and compounds of higher functionality frequently represent less than about 10% by weight, for example & less than about 5%

  
  <EMI ID = 32.1>

  
polyglycidyl resin. The diglycidyl compounds usually represent at least about 75% by weight, for example, about 90 or 95 and essentially up to 100% by weight of the resin. The viscosity of the polyglycidyl resin can often be between about 1,000 and 30,000, for example, between about
4,000 and 25,000 centipoises and many interesting polyglycidyl resins have viscosities of about 5,000 to 15,000 or 20,000 centipoises at 25 [deg.] C.

  
The polyglycidyl resins useful for making the tubular sheets of the present invention are often obtained in the form of the glycidyl product of a reaction between a compound forming glycidyl groups, for example, an epihalohydrin such as

  
  <EMI ID = 33.1>

  
reactions of a glycidyl product &#65533; there are, for example, those in which epichloro-

  
  <EMI ID = 34.1>

  
the formation of an intermediate product of chlorohydrin and (2) the dehydrohalogenation of the intermediate product into glycidyl compound. These reactions are generally described in the literature relating to the epoxy technique (see, for example, Lee and Neville &#65533; "Handbook of Epoxy Resins". 1967).

  
Polyglycidyl resins can be generally characterized by the presence of several glycidyl groups having the following general structure:

  

  <EMI ID = 35.1>


  
The organic compounds forming the polyglycidyl resin can be aliphatic hydrocarbons, they can contain aromatic hydrocarbon groups or they can even have a heterocyclic ring structure. Organic compounds can be

  
1 characterized by the presence of active hydrogen groups, for example, alcohol or amine groups in which the hydrogen is replaced by the glycidyl group. These active hydrogen alcohols and / or amines groups may even be present in the heterocyclic configuration, for example, in the form of a triazine or hydantotne.

  
Among the more preferred and useful polyglycidyl resins useful for making the tabular sheets of the present invention are any polyglycidyl resin consisting of the glycidyl reaction product of a glycidyl group-forming compound, e.g., epichlorohydrin, with n any compound selected from bisphenol A, resorcinol, catechol, hydroquinone, phloroglacinol, 4,4'-

  
  <EMI ID = 36.1>

  
lene glycol, propylene glycol, butane diol, pentane diol, isopentane diol, linoleic acid di-

  
  <EMI ID = 37.1>

  
2,2'tetra- (p-hydroxyphenyl) ethane, phenol / formaldehyde novolak, o-crespl / formaldehyde novolak, cycloaliphatic alcohols and mixtures thereof. These reactive compounds can be substituted, for example, by hydroxy groups or halogen atoms such as fluorine, chlorine and bromine. One of these substituted organic compounds is the tetrabrominated bisphenol A.

  
It is more preferable that the polyglycidyl resin consists of the glycidyl reaction product of a glycidyl group-forming compound.

  
  <EMI ID = 38.1>

  
1 <EMI ID = 39.1>

  
nel of the polyglycidyl resin based on a phenol / formaldehyde novolak is sometimes called

  
  <EMI ID = 40.1>

  
of bisphenol F "or" phenol / formaldehyde novolak polyglycidyl ether ". It is far preferable for the polyglycidyl resin to consist of the glycidyl reaction product of bisphenol A and a compound forming glycidyl groups. This preferred polyglycidyl resin is usually called "bisphenol A diglycidyl ether" or "bisphenol A epoxy resin" and it is generally represented as a mixture of diglycidyl polyethers before the following chemical structural formula:

  

  <EMI ID = 41.1>


  
where n often represents a number between 0 and 1,

  
  <EMI ID = 42.1>

  
In one aspect of the present invention, the polyglycidyl resin contains a large amount of diglycidyl ether having a weight average molecular weight of at least about 300, as well as a small amount of diglycidyl ether having a weight average molecular weight less than about 300., so that the resin has a desired viscosity. Preferably, the higher molecular weight diglycidyl ethers contain aromatic groups in order to impart physical and chemical resistance to the tubular sheet.

   However, these higher molecular weight diglycidyl ethers often have high viscosities which may be inconvenient to insure penetration between hollow fiber membranes; moreover, these diglycidyl ethers can react quite slowly with the agents

  
  <EMI ID = 43.1>

  
The lower rings generally have lower viscosities than higher molecular weight diglycidyl ethers and therefore can be used to reduce the viscosity of the resin. As a result, they are often called "reactive diluents". Since the diglycidyl ethers of a lower molecular weight advantageously comprise two glycidyl groups, they do not tend to come to be placed at the termination of the structure of the polymer chain during hardening. As a result, diglycidyl ethers of lower molecular weight do not significantly alter the physical and chemical resistance of the tubular sheet as could be the case with a monofunctional glycidyl ether.

   In addition, diglycidyl ethers of lower molecular weight can react more quickly with the curing agent, thereby promoting a desirable increase in the viscosity of the liquid resin composition during the early stages of curing, so that deposition exaggerated load cannot occur.

  
By using at least two diglycidyl ethers of variable molecular weight in the polyglycidyl resin, there is great flexibility

  
in the choice of diglycidyl ethers to be used to make the tubular sheet. For example, a diglycidyl ether, which may have excellent physical and chemical resistance properties, may be deficient in wicking, viscosity or reactivity

  
and it can be combined with another diglycidyl ether in order to remedy one or more of these deficiencies without however excessively altering the advantageous properties ensured by the first diglycidyl ether. Frequently &#65533; diglycidyl ethers of higher molecular weight have weight average molecular weights of about 300 to 500 or 600, for example, about 300 to 400, preferably about
330 to 390, as well as viscosities of around 4,000 to <EMI ID = 44.1> preferred dyler of higher molecular weight is the diglycidyl ether of bisphenol A. Among other useful diglycidyl ethers of higher molecular weight are the 4,4'- diglycidyl ethers

  
  <EMI ID = 45.1>

  
butane, bis (2-hydroxynaphthyl) methane, 2,2'-bis (4hydroxyphenyl) butane, 4,4'-dihydroxydiphenyl-

  
  <EMI ID = 46.1>

  
bis-resorcinol F, bisphenolhexafluoracetone, 1,1-bis (4-hydroxyphenyl) ethane or other similar compounds, for example, those having two groups

  
  <EMI ID = 47.1>

  
of lower molecular weight frequently have weight average molecular weights less than about
300, for example, from about 210 to 250. Preferably, diglycidyl ethers of lower molecular weight have viscosities of less than about 5,000

  
  <EMI ID = 48.1>

  
Among suitable diglycidyl ethers of lower molecular weight are ethers

  
  <EMI ID = 49.1>

  
contains 4 to 10 carbon atoms, for example, a butyl group, a pentyl group, a neopentyl group, a 2-methylbutyl group, a hexyl group, a decyl group, etc. ; a phenyl diglycidyl ether or an alkaryl diglycidyl ether in which the alkaryl group

  
  <EMI ID = 50.1>

  
preferred glycidyls of lower molecular weight are the alkyl diglycidyl ethers in which the alkyl group contains 4 to 7 carbon atoms, <EMI ID = 51.1>

  
mentally known as "neopentyl glycol diglycidyl ether"). Preferably, the diglycidyl ethers of a lower molecular weight have very low vapor pressures so as to minimize the risks of inhalation of diglycidyl ethers evaporated during the preparation of the liquid resinous composition or during the manufacture of the tubular sheet. Very often, the diglycidyl ether of a weight

  
  <EMI ID = 52.1>

  
  <EMI ID = 53.1>

  
by weight of the polyglycidyl resin.

  
The resin may also contain a monoglycidyl compound and, very often, commercially available polyglycidyl resins contain monoglycidyl compounds as impurities or as additives. Monoglycidyl compounds are often used to reduce the viscosity of the liquid resin composition and are sometimes called "reactive diluents". Since the monoglycidyl compounds react with the curing agent, they become incorporated into the cured epoxy structure. The monoglycidyl compounds also serve to stop the curing reactions and therefore these monoglycidyl compounds usually represent less than about 40 preferably less than about 30% by weight of the resin.

   In cases where high physical strength and high chemical resistance in the tubular sheet are essential, it is preferable that the possible monoglycidyl compounds represent less than about 10, for example, essentially 0 to about 5% by weight of the resin. Among the monoglycidyl compounds are, for example, butyl glycidyl ether, pentyl glycidyl ether, phenyl glycidyl ether, 2-ethylhexanol glycidyl ether, etc.

  
Usually, in the epoxy resin technique, glycidyl resins are characterized by

  
  <EMI ID = 54.1>

  
epoxy "& that is, the weight (in grams) of the glycidyl resin containing one gram equivalent of epoxy resin. Therefore, in a diglycidyl compound, the" epoxy equivalent weight "would be half the molecular weight of the compound. The epoxy equivalent weight is useful in assisting in determining the amount of curing agent to be used in the liquid resin composition. Frequently, the resins used to make the tubular sheets of the present invention have " epoxy equivalent weights "of approximately 75 to 300, for example, of approximately 125 to 250 and most often, of approximately
150 to 200 g. Some interesting resins have "epoxy equivalent weights" of about 150 to 180 g.

  
The resin of the liquid resin composition may also contain other polymeric materials

  
which are in the liquid phase in the liquid resinous composition and are solidified when this composition is solidified. Among the other polymeric materials,

  
there may be mentioned, for example, phenolic resins, polycarbonates., polysulfones, polyimides,

  
polyamides, etc. If used, these other resins usually represent less than about
10% by weight of the resin. The liquid resinous composition also contains a curing agent composition. This curing agent composition can contain one or more compounds having groups reacting with glycidyl groups and it can include compounds which, for example, catalyze the curing reaction. Preferably, the compounds involved in the composition of hardening agent can consume (either by direct reaction soit or by catalysis) at least about two glycidyl groups per molecule.

   Therefore, the preferred compounds for the curing agent composition are usually at least difunctional, although it is perfectly possible to use monofunctional compounds promoting complementary reactions of glycidyl groups. Among the compounds comprising at least one functional group capable of reacting with a glycidyl group, there are, for example, polyamines such as isopropylamine,

  
  <EMI ID = 55.1>

  
diphenylmethane, diaminodiphenylsulfone, pipera &#65533; zine, N-methylpiperazine, piperidiae, 2,4,6-

  
  <EMI ID = 56.1>

  
such as halohydrin ethers of glycol polyamine adducts, adducts

  
  <EMI ID = 57.1>

  
imidazole-based, etc .; acid hardening agents such as boron trifluoride, aluminum chloride, boron trifluoride monoethylamine, maleic anhydride, phthalic anhydride, chlorendic anhydride, pyromellitic dianhydride, benzophenone-tetracarboxylic dianhydride, l dodecenyl succinic anhydride, nadic methyl anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, etc. ; amides such

  
as amidopolyamines, fatty polyamides, phosphorus amides (for example, p-phenylene bis (anilinophenylphosphine-oxide)); ureas (including

  
substituted ureas and urea-formaldehyde compounds);

  
N, N-diallylmelamine; triallyl cyanurate;

  
hydrazides; aminoacetals such as bis (2-

  
  <EMI ID = 58.1>

  
ethoxy) ethane and the like.

  
One of the preferred groups of compounds used for the curing of polyglycidyl resins is that of imidazole-based curing agents as described by A. Zampini in a related patent application of the Applicant, mentioned here by reference (partially following United States Patent Application No. [deg.] 109,428 filed

  
January 3, 1980).

  
The imidazole-based hardening agents which can be used in the production of the tubular sheets of the present invention, can be represented by the following structural formula:

  

  <EMI ID = 59.1>


  
  <EMI ID = 60.1>

  
or different and each represents a hydrogen atom, an alkyl group (for example, an alkyl group containing 1 to about 12 carbon atoms, preferably a lower alkyl group containing 1 to about 4 or 6 carbon atoms), a lower acyl group (for example, an acyl group containing 1 to about 4 or 6 carbon atoms), an aryl group or an aralkyl group (for example, a monccyclic or bicyclic aryl or aralkyl group containing 6 to about 15

  
  <EMI ID = 61.1>

  
each have a halogen atom (for example, a chlorine atom, a fluorine atom or a bromine atom), a nitro group, a hydroxy group, an alkoxy group
(for example, an alkoxy group containing 1 to about 6

  
  <EMI ID = 62.1>

  
can be brought together, for example, to form a benzi-

  
  <EMI ID = 63.1>

  
*

  
be substituted, for example, by a hydroxy group or by a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom. Among the agents

  
  <EMI ID = 64.1>

  
imidazole and benzimidazole. Preferably, the imidazole-based curing agent is liquid (including

  
a supercooled liquid) at a temperature below about 40 [deg.] C or it is soluble in the polyglycidy-

  
  <EMI ID = 65.1>

  
  <EMI ID = 66.1>

  
aryl group (including an aralkyl group). A preferred imidazole curing agent is 2-ethyl-4methylimidazole. 2-Ethyl-4-methylimidazole (for example, at a purity of about 92%) is an over-molten liquid at room temperature and at this temperature has a viscosity of about 4,000 to 6,000 centipoise.

  
Imidazole curing agents can provide sufficient processing time with the liquid resin composition, even at slightly elevated temperatures, before the viscosity of this liquid resin composition begins to increase significantly

  
as a result of hardening, in order to facilitate the penetration of this liquid resinous composition into a bundle of hollow fiber membranes. In addition, we

  
found not only that hardening agents based on imidazole could ensure the low viscosities necessary to allow this penetration of the liquid resinous composition, but also that the flow properties (rheology) of the liquid resinous composition could be suitable for assu -

  
  <EMI ID = 67.1>

  
hollow fibers without having to resort to significant forces such as those exerted by centrifugal casting. Another advantage is that excessively high maximum exothermic temperatures can be avoided, since the liquid resin composition containing the imidazole curing agent may need to be heated, for example, to about 40 [deg .] C or higher, to initiate a rapid curing reaction which would tend to give rise to elevated temperatures following exothermic curing reactions. Much of the hardening takes place at lower temperatures,

  
a relatively uniform temperature profile can be more easily maintained throughout the mass of the resinous composition during curing. Although imidazole-based hardeners may not be able to eliminate the wicking effect, the degree of the wicking is generally not excessive.

  
In addition, since it is very often possible to obtain good penetration of the liquid resin composition throughout the bundle, the height of the wicking effect occurring across the cross section of this bundle can be relatively uniform.

  
An important advantage of imidazole-based curing agents is their ability to vary the degree of possible exothermic reaction of the liquid resin composition during curing.

  
  <EMI ID = 68.1>

  
imidazole hardeners not only react with epoxy moieties via one or both of the cyclic nitrogen atoms, but also catalyze the reactions between: (1) an alkoxide ion formed by the reaction of the epoxy fraction with a cyclic nitrogen atom of the imidazole curing agent and (2) another epoxy fraction. In "Imidazole Catalysts in the Curing of Epoxy Resins" by

  
  <EMI ID = 69.1>

  
volume 12, pages 159-168 (1968), reproduced here for reference, a more detailed description is given of how it is believed that epoxy moieties react with imidazole compounds. Therefore, since the imidazole curing agent can give rise to two mechanisms for curing an epoxy resin, the relative amount of the imidazole curing agent used can influence the relative phases of these mechanisms occur during the hardening of the epoxy resin. For example, smaller amounts of the imidazole-based curing agent per given amount of epoxy resin would tend to promote stronger crosslinking via alkoxide ions while, with stronger

  
  <EMI ID = 70.1>

  
Large amounts of epoxy moieties are consumed by reaction with the nitrogen atoms of the imidazole ring, so that there are fewer epoxy moieties available for crosslinking with alkoxide ions which may be present. It is possible to choose an amount of this imidazole hardening agent in order to reach a maximum temperature which can be tolerated by hollow fiber membranes with sufficient crosslinking giving the tubular sheet advantageous properties with regard to physical strength and resistance to chemicals.

  
In a preferred aspect of the invention, the curing agent composition contains at least two curing agents, a viscosity increasing agent and a solidifying agent capable of providing stepwise curing reactions. The viscosity increasing agent reacts quickly with the glycidyl groups of the liquid resin composition and is used in an amount sufficient to increase the viscosity of this composition so as to reduce the tendency of the filler to settle. However, the amount of this viscosity increasing agent should be low enough not to raise the temperature of the liquid resin composition excessively.

   Frequently, the amount of this viscosity increasing agent is sufficient to bring the viscosity of the liquid resinous composition (in the absence of any other curing agent or other curing catalyst) to at least about 20,000, for example, to at least about 50,000 centipoises to
25 [deg.] C. Preferably, the viscosity increasing agent

  
has a sufficiently high reaction speed so that

  
  <EMI ID = 71.1>

  
for example, in a period of about 0.5 to 4 hours. Among the compounds which may be useful as viscosity increasing agents, there are compounds which are not excessively reactive with the solidifying agent of the curing composition. Among the suitable viscosity increasing agents there are polyamines, for example, those having at least two primary amino groups, for example, polymethylenediamines, polyalkylether diamines, dialkylene triamines
(e.g., diethylene triamine), trialkylenetetramines (such as triethylene tetramine),

  
  <EMI ID = 72.1>

  
ethyl-piperazine and the like; polyamides; the salts of tertiary amines and the like. Very often the desirable viscosity increasing agents are substantially non-catalytic, that is, each of the reactive seats of this viscosity increasing agent can cause the reaction of a single glycidyl group.

  
As a result, the viscosity increasing agent is generally present in an amount of less than about
40, in particular, in an amount of about 1 to 40, per

  
  <EMI ID = 73.1>

  
to ensure complete reaction with the glycidyl groups of the liquid resin composition.

  
The solidifying agent involved in the hardening agent composition is provided in an amount at least sufficient to solidify the liquid resinous composition. The solidifying agent has, with respect to the glycidyl groups, a lower reactivity than. that of the agent increasing the viscosity. For example, at lower temperatures, especially below a starting temperature, for example, at a temperature of about 30 or
[Deg.] C, for many solidifiers, these may have little or no reactivity with glycidyl groups; however, when the temperature of the liquid resin composition is raised, the reaction between the solidifying agent and the glycidyl groups can take place and can even take place quickly.

   Consequently, the solidifying agent prolongs the duration of the curing reaction and thus makes it possible to dissipate the heat released during the curing reaction in order to avoid excessive temperatures. Since the viscosity increasing agent adequately maintains the filler in suspension in the liquid resin composition, the extended curing time can advantageously be used. Suitable solidifiers often include slower reacting curing agents such as secondary amines, hindered primary amines, anhydride curing agents and the like, as described above.

   Frequently, the appropriate solidifying agents have pot life in the liquid resin composition of at least about 3, especially at least about 4, for example, from about 4 to 24 hours at 35 [deg.] C. Particularly preferred solidifying agents for the manufacture of tubular sheets of high physical strength and high resistance to chemicals are those which, directly or indirectly (for example, by catalysis) consume three or more glycidyl groups per molecule. Among these preferred solidifying agents, there may be mentioned, for example,

  
curing agents based on imidazole such as those described above. A highly supportive solidifying agent

  
  <EMI ID = 74.1>

  
desirable solidifying agent is methylene dianiline or a mixture of dimethylaniline and diphenylamine.

  
The solidifying agent is provided in an amount sufficient for the curing agent composition to consume at least about 90, preferably at least

  
  <EMI ID = 75.1>

  
functionally reactive groups provided by the curing agent composition do not react. When solidifiers having catalytic activity are used to promote additional reactions consuming glycidyl groups, the amount of these agents can often influence the degree of crosslinking, i.e. the number of glycidyl groups consumed per molecule d hardening agent. With solidifying agents such as hardening agents based on imida-zole, the amount of these generally influences the degree of crosslinking.

   Frequently, catalytic solidifiers are provided in an amount between about 2 and 40, for example, between about 2 and 30, preferably between about 5 and 20% of the amount required to ensure complete reaction with the curing agent catalytic and this, on a stoichiometric basis. According to an advantageous characteristic, the viscosity-increasing agent can consume glycidyl groups in an amount sufficient to make it possible to use smaller amounts of these catalytic solidifying agents and, consequently, to obtain a higher degree of crosslinking than if the 'this viscosity-enhancing agent was not used.

   These catalytic solidifying agents are very often used in an amount of about 0.01 to 0.5, for example, about 0.02 to 0.25 mole of catalytic solidifying agent per mole of glycidyl group of the resinous composition liquid. The molar ratio between the viscosity increasing agent and the solidifying agent is frequently from about 0.5: 1 to 2: 1, especially from about 0.1: 1 to 1: 1, for example, from about 0.1: 1 to 0.7: 1.

  
The liquid resinous composition may contain other components such as plasticizers, antiplasticizers, binding promoting agents, curing accelerators, thickening agents, colorants and pigments. Among the plasticizers are phthalates (for example, dibutyl phthalate and dioctyl phthalate), tricresyl phosphate and the like. Among the binding promoting agents are tertiary amines such as benzyldimethylamine, N-methylmorpholine, dimethylaminopropylamine and the like. Among the accelerators are resorcinol, nonyl phenol, bisphenol A, triphenyl phosphate, toluene sulfonic acid, lactic acid, salicylic acid and the like.

  
Among the thickening agents, there are solids very finely divided (for example, into particles with an average maximum size less than 1 micron and often having a specific surface greater than about 3 or 5 m2 / g), for example, the colloidal silica, clays and the like. Most frequently, accelerators and thickeners are not required to obtain liquid resinous compositions suitable for forming tubular sheets according to the present invention.

  
In many cases, at least about 95, for example, at least about 98 and essentially up to 100% by weight of the liquid resin composition may consist of the resin, the curing agent composition and the filler. The viscosity of the liquid resin composition is frequently about
1,000 to 15,000, for example, from about 1,000 to 10,000 and, better still, from about 1,000 to 6,000 or 7,000 centipoi-

  
  <EMI ID = 76.1>

  
The liquid resin composition can be brought to the shape of the tubular sheet in any suitable manner. For example, the liquid resin can be deposited on the ends of several hollow fiber membranes which are then brought together

  
in the form of a bundle as described in the patents of the United States of America n [deg.] 3,455,460 (Mahon) and
3,690,465 (McCinnis et al), used here for reference. In this type of assembly, the ends of the hollow fiber membranes are joined together to form a one-piece resinous tubular sheet.

  
According to a more advantageous characteristic, the liquid resinous compositions are particularly useful for forming tubular sheets by casting these compositions around a bundle previously assembled and containing several membranes with hollow fibers. his. These casting methods for forming tubular sheets are highly preferred because they are simple and do not require complex manufacturing equipment. For example, in these casting processes, a bundle of membranes is deposited

  
with hollow fibers in a mold, the ends of the conduits of the hollow fiber membranes being generally sealed or the membranes of the hollow fibers being wound in loops so that the liquid resinous composition is not drawn into the conduits. The liquid resin composition is then introduced into the mold and it is thus poured practically in the configuration of the tubular sheet. When the liquid resin composition is poured to form the tubular sheet, it is preferable that its viscosity reaches about 6,000, especially about 500 or 1,000 to 5,000, for example, about 1,000 to 4,000 centipoise at the casting temperature.

   Casting can be carried out at an elevated temperature to reduce the viscosity of the liquid resin composition; however, excessively high casting temperatures can accelerate the curing reactions of the resin and can give rise to untimely temperatures due to exothermic reactions. As a result, the temperature of the liquid resin composition during casting is often less than about 45 [deg.] C, for example,

  
  <EMI ID = 77.1>

  
Any suitable program for curing the resin can be adopted when making the tubular sheets of the present invention. In many cases, curing the composition

  
  <EMI ID = 78.1>

  
curing hardening; (2) solidification and (3) final crosslinking. In this case, the conditions to which the resin is subjected during hardening, can influence the speed of the latter, the maximum temperature reached by the resin during hardening, as well as the degree of crosslinking of the resin, Frequently , although hardening can be initiated at

  
  <EMI ID = 79.1>

  
facilitate the initiation of curing reactions. Preferably, the temperature is lower than that at which the reaction becomes so rapid that most of the heat given off cannot be dissipated and too high temperatures are reached which further accelerate the reaction. In this specification, this phenomenon is called "exothermic reaction" and the maximum temperature reached during curing is called "maximum exothermic temperature". The speed at which hardening is initiated can influence the maximum temperature which is reached during the exothermic reaction.

   Preferably, the temperature of the liquid resinous composition during the initiation step of the curing is calculated so as not to reach inopportune maximum exothermic temperatures. The maximum exothermic temperature of the curing reaction should be lower than the temperature at which the hollow fiber membranes are too altered, for example, in terms of physical strength, chemical resistance and / or permeation properties. The maximum exothermic temperature of the curing reaction is frequently lower

  
at least 10 or 20 [deg.] C at the vitrification temperature of the hollow fiber membrane. When heat is expected, the temperature of the liquid resinous composition

  
  <EMI ID = 80.1>

  
The solidification step of the curing reaction is usually carried out at "high temperatures due to the heat given off during the curing reactions. If necessary, heat can be supplied to the curing resin in order to to ensure a desirable reaction rate, however, as soon as they are initiated, the curing reactions usually take place until the resin solidifies without the need to provide a supply of heat. solidification is advantageously at least 10 or 20 [deg.] C below the vitrification temperature of the hollow fiber membrane.

   The maximum exothermic temperature during solidification is less than about 150 [deg.] C, for example, less than about 130 [deg.] C, especially about 25 to

  
120 [deg.] C.

  
Towards the end of the curing reaction, it slows down because the concentration of reactants

  
is significantly reduced. During the final crosslinking step (optional step), the temperature of the resin is raised # for example &#65533; in order to promote the mobility of the reagents and ensure additional crosslinking (hardening), this additional crosslinking can significantly increase the physical and chemical resistance of the tubular sheet, although the degree of crosslinking is low. Generally, the temperatures adopted for the final crosslinking are lower by less

  
  <EMI ID = 81.1>

  
hollow fiber membranes. With hollow fiber membranes with high thermal stability, the mass during hardening can reach temperatures

  
  <EMI ID = 82.1> <EMI ID = 83.1>

  
final crosslinking of curing reactions generally depends on the desired degree of crosslinking. In case of excessive crosslinking, the tubular sheet may be disadvantageously fragile. Frequently, the duration of this heating is sufficient to ensure a practically uniform temperature throughout the tubular sheet. Very often, this duration is at least about 1 hour, for example, at least about 2 hours. A time greater than about 24 or 36 hours may be less desirable due to the time required for the manufacture of the tubular sheet. Preferably, the duration of this heating is about 1 to 24 hours, for example, about 1 to 16 hours.

  
In the aspect of the present invention that the curing agent composition contains a viscosity increasing agent and a solidifying agent,

  
  <EMI ID = 84.1>

  
and two priming steps may be necessary, the first consisting in initiating the reaction of the viscosity increasing agent, while the second takes place at a higher temperature, that is to say; very often a temperature higher by at least about S [deg.] C, for example, from about 5 to 20 [deg.] C, in order to initiate the reaction of the solidifying agent.

  
In a preferred embodiment, the curing of the liquid resinous composition is carried out so that the temperature of the tubular sheet during curing is sufficiently uniform throughout its volume so as not to give rise to exaggerated tensions. Very often the differences in exothermic temperature. maximum in volume

  
of the tubular sheet during hardening are less than about 40 ° C and most frequently inferior

  
  <EMI ID = 85.1>

  
Maximum exothermic temperatures are less than about 20 [deg.] C. The time during which these maximum exothermic temperatures remain can obviously vary throughout the volume of the tubular sheet.

  
Since the curing reactions are exothermic, in many cases the mold is insulated or even heated in order to avoid excessive cooling of the outer areas of the tubular sheet and now

  
  <EMI ID = 86.1>

  
the interior areas of the tubular sheet. As a result, the hardening of the resinous composition

  
  <EMI ID = 87.1>

  
absorbing a significant amount of the heat given off by exothermic curing reactions, while the rate of heat dissipation in the ambient medium is sufficiently low to avoid excessive temperature differences during curing, these differences being able to favor the appearance of tensions in the tubular sheet.

  
-After forming the tubular sheet, for example, by assembling a bundle of hollow fiber membranes comprising liquid resinous compositions at its ends, or by casting, the tubular sheet is generally cut to expose the conduits of the fiber membranes hollow.

  
Permeation devices containing hollow fiber membranes, and in which tubular sheets are usually used, are generally

  
  <EMI ID = 88.1>

  
elongated sheet comprising with care an open end intended to receive a tubular sheet; an end closure cap essentially impermeable to fluids, fixed to and covering the elongated tubular envelope at the open end, this closure cap comprising at least one fluid communication lumen; multiple hollow fiber membranes which are generally parallel and extend longitudinally to form at least one bundle in the elongated tubular shell; a tubular sheet in which is embedded, in a sealing relationship to fluids, at least one end of each of the hollow fiber membranes, so that the conduits of your membranes are in fluid communication via the tubular sheet;

   as well as at least one fluid introduction lumen and at least one fluid discharge lumen communicating via the elongated tubular casing. This elongated tubular casing may have &#65533; in cross section, any configuration suitable for retaining the bundle of hollow fiber membranes. This tubular envelope advantageously has a circular cross section and the bundle of hollow fiber membranes practically fills the cross section of the tubular envelope. However, cross sections with other configurations can be adopted, for example, rectangular, oval, free-form or the like cross sections.

  
The permeation apparatus may be of the single or double end type. A permeation device

  
single-ended has a tubular sheet at one end, while one or both ends

  
hollow fiber membranes are coated in this tubular sheet. When only one end of each of the hollow fiber membranes is coated in this tubular sheet, the other end must be provided with a plug or otherwise closed. In a double-ended permeation apparatus, a tubular sheet is provided at each end of the tubular casing, while the hollow fiber membranes can extend from one tubular sheet to the other,

  
or the permeation apparatus may comprise at least two distinct bundles of hollow fiber membranes, at least one of these bundles extending in

  
a single tubular sheet. In many cases, a single bundle of hollow fiber membranes is used in a permeation apparatus and at least one end. hollow fiber membranes of the bundle is wrapped in a tubular sheet. The opposite end of the hollow fiber membranes can be bent, that is <EMI ID = 89.1>

  
while it is wrapped in the same tubular sheet;

  
similarly, the opposite end of the hollow fiber membranes may be provided with a plug or coated in another tubular sheet. When the membranes to

  
  <EMI ID = 90.1>

  
ends can be segmented so that different areas of the tubular sheet contain each end of the hollow fiber membranes. Each of these areas formed on a tubular sheet can be maintained in a substantially fluid impermeable relationship so that fluid communication between these areas can only take place by the passage of the fluid through the conduits of the hollow fiber membranes.

  
The permeation apparatus can operate in any desired manner; for example, the mixture of fluid charge can be introduced into the envelope and it will initially come into contact with the face of the hollow fiber membranes which faces this envelope; similarly, this mixture can be introduced into the conduits of hollow fiber membranes. The type of fluid flow on the face of the hollow fiber membranes which faces towards the envelope can be mainly transverse to the longitudinal orientation of the hollow fiber membranes or it can be mainly axial with respect to the orientation of these membranes.

  
In the presence of an axial flow on the face of the hollow fiber membranes which faces the envelope, this flow can generally be carried out in the same direction or against the current with respect to

  
to the flow taking place in the conduits of hollow fiber membranes.

  
The tubular sheets are in a fluid-tight relation to life of the tubular casing. This sealing relationship to fluids is usually obtained by installing a sealing element between the tubular sheet and at least the end closure cap or the tubular casing, for example, the sealing elements may be O-rings or flat seals which are installed between the face of the tubular sheet and the inner surface of the tubular casing as described in the patents of

  
  <EMI ID = 91.1>

  
McNamara et al. and 4,061,574 on behalf of Clarke &#65533; all these patents are listed here for reference. As a variant, the fluid tightness relationships can be ensured by installing an O-ring or another flat seal between the end face of the tubular sheet or a lateral projection of this sheet and the end closure cap as described in the patent applications of the United States of America n [deg.] 151,003

  
  <EMI ID = 92.1>

  
to United States patent application no [deg.]
972.642 filed December 22, 1978 and now discontinued) and 086.211 (Bollinger et al.) Filed October 18, 1979, these two patent applications being listed here for reference. So that each of the hollow fiber membranes is embedded in the tubular sheet and in order to create &#65533; in the latter, areas of sufficient thickness, for example, to receive O-rings or other flat seals ensuring sealing, the peripheral dimensions of the tubular sheet usually extend outside the area of this sheet through which the bundle of hollow fiber membranes passes.

   Thus, the tubular sheet has an area having a large number of hollow fiber membranes, as well as a relatively free area of hollow fiber membranes. These zones may, for example, have different curing properties, in particular different maximum exothermic temperatures during the curing solidification step, this due to the difference in density of the resins between these zones. Thanks to the liquid resinous compositions used to form the tubular sheets of the present invention, the zone relatively free of hollow fiber membranes can have sufficient dimensions to ensure the desired coating of these membranes and to form adequate zones for the tubular sheet to be in a fluid tightness relationship.

   It is highly desirable that the average peripheral dimension around the tubular sheet is greater

  
  <EMI ID = 93.1>

  
average of the area of the tubular sheet through which the bundle of hollow fiber membranes passes. In many cases, the difference between these

  
  <EMI ID = 94.1>

  
area of the tabular sheet which contains the hollow fiber membranes, may comprise the latter in a relatively high density. Usually, the density of hollow fiber membranes is expressed in terms of density factor which is the percentage of a given cross section occupied by hollow fiber membranes based on the dimensions of the latter in cross section. According to an advantageous characteristic, the present invention makes it possible to produce desirable tubular sheets comprising bundles having high density factors on the basis of the peripheral dimensions of the bundle contained in the tubular sheet, for example, factors

  
  <EMI ID = 95.1>

  
for example, up to about 65 or 70% and most commonly about 50 to 60%.

  
The tubular sheet frequently has an average cross-sectional dimension (for example, a diameter with tubular sheets having circular cross-sectional configurations) of at least about 1 or 2 cm. Although this average cross-sectional dimension can reach up to 1 m or more, many tubular sheets have, in cross-section, average dimensions of at least about 0.02, preferably at least about 0, 05 to 1 m.

  
The length of the tubular sheet (determined in a direction parallel to the general orientation of the bundle of hollow fiber membranes through the tubular sheet) is generally sufficient to provide adequate resistance to the total pressure differences at which the tubular sheet can

  
  <EMI ID = 96.1>

  
aged. Thus the length adopted may depend on the physical strength of the hardened resin. Likewise, the tubular sheet must have a sufficient length to ensure ample contact between the tubes and the hardened resin in order to obtain essentially a sealing relationship with respect to the fluids. Consequently, the adhesion between the tubes and the material of the tubular sheet will also influence the desired length of the tubular sheets, very often the sheets

  
  <EMI ID = 97.1>

  
for example, from about 2 to 100 cm, in particular., from about 2 to 25 or 50 cm.

  
The volume of the liquid resin composition used to form the tubular sheets of the present invention will vary depending on the dimensions of the tubular sheet and the part of the volume thereof which is occupied by the hollow fiber membranes. Very often, it takes more than about 500 or 1,000 to 1,500 g of the liquid resinous composition to manufacture the tubular sheet and the liquid resinous compositions of the present invention make it possible to manufacture these large tubular sheets in a single casting without this results in intolerable risks of deterioration of the hollow fiber membranes due to the heat given off during the curing of the resin.

  
Hollow fiber membranes can be made from any natural or synthetic material suitable for separating fluids or for supporting materials providing fluid separations. The material used to form the hollow fiber membranes can be chosen on the basis of the heat resistance, the resistance to chemicals and / or the mechanical resistance which it is desired to confer on these membranes, as well as on the base of other factors determined by the separation of fluids envisaged for which it will be used and also according to the operating conditions to which it will be subjected. The material used to form the hollow fibers can be an inorganic material, an organic material or a mixed inorganic and organic material.

   Among the specific inorganic materials there are glasses & ceramic materials, cermets, metals and the like,

  
Organic materials are usually polymers. Among the specific polymers that can be used for hollow fiber membranes,

  
  <EMI ID = 98.1>. Located among the polysulfones; poly (styrenes), including copolymers containing styrene such as <EMI ID = 99.1>

  
cellulosic res such as cellulose aceto-butyrate, <EMI ID = 100.1>

  
and polyimides, in particular arylpolyamides, arylpolyimides and copolymers of polyamides, polyethers; pclyacetals; polyarylene oxides such as polyphenylene oxide and

  
  <EMI ID = 101.1>

  
polyurethanes; polyesters (including polyarylates) such as polyethylene terephthalate, polyalkyl methacrylates &#65533; polyalky acrylates-

  
  <EMI ID = 102.1>

  
of those mentioned above, for example, polyethylene, polypropylene, polybutene-1, poly (4-methylpentene-1), polyvinyl compounds, for example, polyvinyl chloride, polyvinyl fluoride, chloride polyvinylidene, fluoride

  
  <EMI ID = 103.1>

  
lyvinyls such as polyvinyl acetate and polyvinyl propiona, te, polyvinyl-pyridines., polyvinyl-pyrrolidones &#65533; polyvinyl ethers, polyvinyl ketones &#65533; polyvinyl aldehydes such as

  
  <EMI ID = 104.1>

  
amines., polyvinyl phosphates and polyvinyl sulfates; polyallylic compounds poly-

  
  <EMI ID = 105.1>

  
polycarbodiimides; polyphosphazins, etc.,

  
as well as the interpolymers &#65533; including block interpolymers containing periodic units selected from those mentioned above, for example,

  
  <EMI ID = 106.1>

  
than grafted polymers and mixtures containing one or the other of the abovementioned polymers. Among the specific substituents giving substituted polymers,

  
there are halogen atoms such as fluorine, chlorine and bromine; hydroxy group; lower alkyl groups; lower alkoxy groups; monocyclic aryl groups; lower acyl groups and the like.

  
The dimensions of the hollow fiber membranes in cross section can be chosen from a wide range; however, hollow fiber membranes must have walls of sufficient thickness to provide adequate physical strength and the conduit (passage) must be large enough so as not to impose excessively high pressure drop on fluids passing through this conduit or so as not to obstruct the latter following the presence of

  
  <EMI ID = 107.1>

  
the outer diameter of the hollow fiber membranes is at least about 20 microns, for example, at least about 30 microns, while a bundle can contain fibers having the same or different outer diameters. Very often, the outside diameter of hollow fiber membranes does not exceed about 800 or 1,000 microns, since hollow fibers having a larger diameter may give less desirable ratios with respect to the specific surface area.

  
  <EMI ID = 108.1>

  
the same with permeation. Preferably, the outer diameter of the hollow fiber membranes is between about 50 and 800 microns and most preferably between about 150 or 300 to 600 or 800 microns. Typically, the wall thickness of hollow fiber membranes is at least about 5 microns and, in some hollow fiber membranes, the wall thickness can reach about 200 or 300 microns, for example, about 50 to 200 microns. In the case of hollow fiber membranes made from materials having a lower physical resistance, it may be necessary to use fibers having larger diameters and greater wall thicknesses in order to impart sufficient physical resistance to the membranes. with hollow fibers.

   The walls of hollow fiber membranes may be essentially full or have a large volume of void spaces. When empty spaces are desirable, the density of the hollow fiber membrane can be essentially the same over the entire thickness of its wall, that is to say that the hollow fiber membrane is isotropic; similarly, the hollow fiber membrane can be characterized in that it comprises, in the thickness of its wall, at least one relatively dense zone in relation to flow obstruction, that is to say that the hollow fiber membrane is anisotropic.

  
Hollow fiber membranes are generally arranged parallel in the form of one or more bundles in the envelope. Typically, a permeation device contains at least about
10,000 and, very often, much higher numbers, for example, up to 1 million or more of hollow fibers.

  
The fibers contained in the bundle can be, for example, relatively rectilinear or they can be wound in a spiral as described in the patent of the United States of America n [deg.] 3,422,008 in the name of McLain.

  
The following examples are given to further illustrate the invention, but they do not limit the latter in any way. In these examples, unless otherwise indicated, all parts and percentages are by weight for liquids and solids, while they are expressed by volume for gases.

  
EXAMPLE 1

  
In an aluminum mold in which a silicone-based release agent has been sprayed, a bundle of approximately 66,000 hollow fiber membranes is deposited, these membranes comprising an outer film with an outside diameter of approximately 560 microns, while they are made from a polysulfone ("P-3500" from "Union Carbide Corporation"): By fusion, the hollow fiber membranes are sealed at the end of the bundle deposited in the mold. This wheel has a cylindrical and slightly conical upper chamber, this chamber having ur. maximum diameter of approximately 24.5 cm at its apex and a depth of 10 cm, as well as a concentric lower chamber having a diameter of
20.3 cm and a depth of 7.6 cm. At the bottom of the mold, a concentric drain hole with a diameter of about 10 cm is provided.

   The mold is heated electrically.

  
The beam is oriented vertically and its lower end engages in the lower chamber of the mold (density factor of approximately 55%, based on the diameter of the lower chamber) and it exits at the top of the mold by describing an elbow. The mold is heated to about 35 [deg.] C.

  
A mixture is prepared comprising approximately
5,400 g of "EPON 826" (trademark for an unmodified bisphenol A epoxy resin having a viscosity of approximately 65-95 poises at 25 [deg.] C and an epoxy equivalent weight of approximately 180 to 190, sold by "Shell Company"),
600 g of neopentyl glycol diglycidyl ether and
3,900 g finely divided aluminum powder (less

  
325 mesh, American sieve) sold under the name of "Reynolds aluminum powder n [deg.] 120" (average particle size: about 20 to 30 microns) from "Reynolds Metal Company", then this mixture is heated to about

  
  <EMI ID = 109.1>

  
240 g of "Versamid 140" (trademark for a reactive polyamide resin having a viscosity of approximately 2 to 6 poises at 75 [deg.] C and an amine number of approximately
370 to 400, this resin being sold by "General Mills, Inc.") and 210 g of 2-ethyl-4-methylimidazole ("EMI 24", trademark of "Fike Chemical Company"), then mixed with the mixture containing the polyglycidyl resins to obtain the liquid resin composition.

  
The mixing operation requires a duration of approximately 5

  
at 10 minutes, after which the liquid resin composition is poured into the mold. About 3 or 4 castings of the liquid resin composition are required to fill the mold cavity, since this liquid resin penetrates inside the bundle. About 150 g of the residual liquid resinous composition are placed in a refrigerator. A large bead is tied around the bundle above the level of the liquid resin contained in the mold so that the diameter of the bundle is approximately 20 to 22 cm. The cord is then slid over the bundle to bring it slightly below the level of the liquid resinous composition.

  
The mold is maintained at 35 [deg.] C for 18 to

  
20 hours, period at the end of which the resin is solidified and has undergone a slight shrinkage. The refrigerated liquid resinous composition is deposited on top of the solidified resin in order to complete the tubular sheet.

  
The temperature of the mold is then brought to 45 [deg.] C for

  
2 hours, then at 55 [deg.] C for 2 hours and then at 65 [deg.] C

  
  <EMI ID = 110.1>

  
at 100 [deg.] C for 2 hours. The mold is allowed to cool to room temperature, then the tubular sheet is removed. The face of this tubular sheet which is turned towards the bundle, undergoes a moderate wicking effect
(for example, less than about 5 cm), this effect being relatively uniform across the beam.

  
Using a hand saw, cut the cross section of the part of the tubular sheet formed by the lower chamber at a distance of approximately 3 to 7 cm from the part formed by the larger chamber of the mold in order to exposing the hollow fiber membranes, that is, to form the face of the tubular sheet. The face of the tubular sheet is then leveled with an electric planer and trimmed with a flat razor blade so that the conduits of the hollow fiber membranes are open to the flow of fluids.

  
This process is repeated with about 98,000 hollow fiber membranes having an outer film, having an outer diameter of about 450 microns and made of a polysulfone ("P-3500"), with the exception that the depth of the upper chamber of the mold is about 15 cm, that the temperature of the liquid resinous composition after casting is about
30 [deg.] C and the mold is maintained at a temperature of approximately 30 [deg.] C for 18 hours (period during which a maximum exothermic temperature of approximately 130 [deg.] C is observed), to then be heated to 60 [deg.] C for about 4 hours, then cooled.

   Usually, with larger tubular sheets having larger volumes of a liquid resinous composition per unit of this area of this tubular sheet, the maximum exothermic temperatures may be higher. Thus, the maximum exothermic temperatures observed and reached using the deeper mold are higher than those reached using the shallower mold having the same dimensions in cross section. However, the maximum exothermic temperatures are reduced by lowering the initial temperature of the mold and the liquid resin composition from about 35 [deg.] C to about 30 [deg.] C. If the initial temperature of the mold and of the liquid resinous composition is approximately 25 [deg.] C, it is not possible to ensure a desirable penetration of this composition into the bundle.

  
EXAMPLE 2

  
The process of Example 1 is practically repeated, with the exception that instead of aluminum powder, a silica coupled to an epoxy is used.

  
  <EMI ID = 111.1>

  
having a specific surface of approximately 2 m2 / g and in particles of an average maximum granularity of approximately

  
5 microns ("NOVAKUP 187", trademark of "Malvern Minerais Company").

  
EXAMPLE 3

  
In an aluminum mold in which a silicone-based release agent has been sprayed, a bundle of approximately 25,000 hollow fiber membranes is deposited, these membranes comprising an external film with an external diameter of approximately 450 microns, while 'They are made from a polysulfone ("P-3500"). The mold comprises a slightly conical upper chamber having, at its top, a maximum diameter of approximately 14.5 cm and a depth of 12.7 cm, as well as a concentric lower chamber having a diameter of 10.3 cm and a depth of 7.6 cm. A concentric drain hole is provided at the bottom of the mold

  
  <EMI ID = 112.1>

  
only the mold. The beam is oriented vertically and its lower end fits in the lower chamber of the mold and it exits through the top of the latter by describing an elbow. We heat the mold to

  
  <EMI ID = 113.1>

  
A liquid resinous composition is prepared practically as described in Example 1, with the exception that the following components are used in the quantities indicated:

  

  <EMI ID = 114.1>


  
Aluminum powder n [deg.] 123 is an aluminum atomized into particles with an average granularity of about 30 microns and a specific surface of about

  
  <EMI ID = 115.1>

  
We adopt practically the same program of

  
  <EMI ID = 116.1> the liquid resin composition in order to form a tubular sheet.

  
EXAMPLES 4 TO 6

  
The procedure of Example 1 is practically repeated, with the exception that the following components are used in the quantities indicated.

  

  <EMI ID = 117.1>


  
The curing program (temperatures and dwell times in the mold, ambient temperature:
approximately 20 to 25 [deg.] C), the time elapsing up to the maximum exothermic temperature, as well as the range of these maximum exothermic temperatures are indicated below:

  

  <EMI ID = 118.1>
 

  
EXAMPLES 7 AND 8

  
Example 3 is practically repeated, with the exception that the following components are used in the quantities indicated in parts by weight

  

  <EMI ID = 119.1>


  
  <EMI ID = 120.1>

  
mixture of decyl-glycidyl ether and a diglycidyl ether of bisphenol A, this mixture having a viscosity of approximately 500 to 700 centipoise at 25 [deg.] C and an epoxy equivalent weight of approximately 189 to 200, while 'it's sold

  
  <EMI ID = 121.1>

  
ciale) is a mixture sold by the Shell Chemical Company and consisting of 80% by weight of a diglycidyl ether of bisphenol A having a viscosity of about 170-22S poises at 25 [deg.] C and an epoxy equivalent weight d '' about 190

  
  <EMI ID = 122.1>

  
monofunctional, this mixture also having a viscosity of 5 to 7 poises at 25 [deg.] C and an epoxy equivalent weight of approximately 195 to 215. "Polyamide 840" is a reactive polyamide resin having an amine index

  
  <EMI ID = 123.1>

  
The resinous compositions are cured at room temperature and then subjected to curing.

  
  <EMI ID = 124.1>

  
giving good tubular sheets.

  
A particularly useful method for evaluating the virtual ability of a liquid resin composition to form a tubular sheet is to pour a mass of the resin roughly representing the amount required to form the tubular sheet, while then observing the curing characteristics. of the resin mass.

  
EXAMPLES 9 TO 15

  
Samples of about 4 liters of the liquid resinous compositions are prepared and poured into heated metal containers, then the liquid resinous compositions are cured. In the example
15, only about 1 liter of the liquid resinous composition is prepared. Table I below gives the relevant details. In this table, the following abbreviations are used:

  
826: "EPON 826" (trademark)

  
  <EMI ID = 125.1>

  
509: "Araldite 509" (trademark) IDA: Isophorone-diamine

  
NDE: 2-ethyl-4-methylimidazole

  
Agent Z: Methylene-dianiline sold by "Shell

  
Chemical Company "

  
NAP: N-aminoethylpiperazine

  
Agent D: Hardening agent based on a salt of

  
polyamine, sold by "Shell Chemical Company",

  
  <EMI ID = 126.1>

  
HHrA: Hexahydrophthalic anhydride

  
Al: Aluminum powder sold by "Alcoa"

  
under the name of "aluminum powder n [deg.] 123"

  
T.A.: Room temperature, around 20 to

  
25 [deg.] C.

  

  <EMI ID = 127.1>


  

  <EMI ID = 128.1>
 

  
EXAMPLES 16 TO 18

  
The process of Example 3 is practically repeated, with the exception that the bundle contains approximately 17,000 hollow fiber polysulfone membranes ("P-3500") having an outer film and an outer diameter of about 560 microns, while the mold and liquid resin temperatures are initially

  
  <EMI ID = 129.1>

  
ron 18 hours, then at 45 [deg.] C for 2 hours and then,

  
at 55 [deg.] C for 2 hours, at 65 [deg.] C for 2 hours, at 75 [deg.] C for 2 hours and finally, at 100 [deg.] C for 2 hours, as indicated in the Table II below. In this table II, the following abbreviations are used:

  
826: "EPON 826" (trademark)

  
8132: "EPON 8132" (trademark)

  
NC: "Novacite 207A" (trademark)

  
from "Malvern Minerals Company" for a silica in particles with an average granularity of approximately 3.6 microns and a specific surface of approximately 2 m2 / g.

  
Fe: Electrolytic iron powder in particles with an average granularity of 6 microns, sold by "Glidden Metals,

  
SMC Corporation "under the name" A-130 electrolytic iron powder ".

  
Cu: Copper powder sold by "Glidden

  
Metals, SMC Corporation "under the name

  
of "500 RL".

  
RD-4: Vinylcyclohexene dioxide sold by

  
"Ciba-Geigy".

  
H-68: "Heloxy63" (trademark)

  
TETA: Triethyl-tetramine

  
V-140: "Versamid 140" (trademark)

  
A-U: Curing agent U, modified quick-setting liquid amine having a viscosity of about 100 poises at 25 [deg.] C, sold by "Shell Chemical Company".

  
NDE: 2-ethyl-4-methylimidazole

TABLE II

  

  <EMI ID = 130.1>



    

Claims (1)

1. Tubular sheet in which are coated with several hollow fiber membranes suitable for the separation of fluids, this sheet tubular being designed to be installed in a fluid tightness relationship within a permeation apparatus, while it is made up a hardened and solidified resinous composition formed from a liquid resinous composition, this last including: at. a resin having a viscosity of about 500 to 12,000 centipoises at 25 [deg.] C and containing a large amount by weight of a polyglycidyl resin having a viscosity of around 1,000 to 30,000 centipoi- <EMI ID = 131.1> b. a curing agent composition by enough to consume at least about 90% of the glycidyl groups of the resinous composition liquid; and vs. a charge of particles having a density of about 1 to 10 g per cm3 at 25 [deg.] C, particles with an average maximum granularity of around 1.5 to 150 microns and a specific surface less than approximately 5 m2 / g, this load representing approximately 5 to less about 35% by volume of the resinous composition liquid, this liquid resinous composition having a viscosity from around 1,000 to 10,000 centipoises at 25 [deg.] C. 2. Tubular sheet according to claim 1, characterized in that the load represents  <EMI ID = 132.1> liquid. 3. Tubular sheet according to claim 1, characterized in that the filler has a surface specific from about 0.1 to 2.5 m2 / g, while the average maximum granularity of its particles is about 2 to 100 microns. 4. Tubular sheet according to claim 1, characterized in that the filler has an aspect ratio of about 1: 1 to 20: 1. 5. Tubular sheet according to claim 3, characterized in that the filler is an inorganic filler or an inorganic filler with organic modification. 6. Tubular sheet according to claim 5, characterized in that the filler consists of a metal. 7. Tubular sheet according to claim 6, characterized in that the filler consists of aluminum powder.  <EMI ID = 133.1> tion 5, characterized in that the filler consists of silica. 9. Tubular sheet according to claim 1, characterized in that the polyglycidyl resin consists of a glycidyl reaction product of a compound forming glycidyl groups and of a compound chosen from bisphenol A, resorcinol, catechol, l 'hydroquinone, phloroglucinol, 4,4'dihydroxybenzophenone, 1,1-bis (4-hydroxypheny? -ethane,  <EMI ID = 134.1> phenyl) butane, 4,4'-dihydroxydiphenyl-sulfone, ethylene glycol, propylene glycol, tutane-diol,  <EMI ID = 135.1> bis-resorcinol F, 2,2 ', 4,4'-tetrahydroxybenzophenone, bisphenol-hexafluoracetone, aniline, paraaminpphenol, isocyanuric acid, hydantoin,  <EMI ID = 136.1> phenolfo rmaldehyde, o-cresol / formaldehyde novolak or a mixture of these compounds. 10. Tubular sheet according to claim 9, characterized in that the polyglycidyic resin consists of a glycidyl reaction product of a compound forming glycidyl groups and bisphenol A or phenol / formaldehyde novolak. 11. Tubular sheet according to claim 10, characterized in that the polyglycidyl resin consists of a mixture of diglycidyl ethers of bisphenol A. 12. Tubular sheet according to claim 9, characterized in that the polyglycidyl resin comprises a large amount by weight of a diglycidyl ether having a weight average molecular weight of at least about 300, as well as a small amount by weight of a diglycidyl ether having a weight average molecular weight of less than about 250, so that the polyglycidyl resin has a viscosity of about 4,000 to 25,000 centipoise at  <EMI ID = 137.1> 13. Tubular sheet according to claim 12, characterized in that the diglycidyl ether of a higher molecular weight has a weight average molecular weight of about 300 to 600 and a viscosity of about 4,000 to 30,000 centipoise at 25 [deg .]VS. 14. Tubular sheet according to claim 12, characterized in that the diglycidyl ether of a lower molecular weight has a weight average molecular weight of about 200 to 250 and a viscosity of less than about 5,000 centipoise at 25 [deg.] vs. 15. Tubular sheet according to claim 12, characterized in that the diglycidyl ether of a lower molecular weight consists of an alkyl diglycidyl ether in which the alkyl group contains 4 to 7 carbon atoms. 16. Tubular sheet according to any one of claims 13 to 15, characterized in that the diglycidyl ether of a higher molecular weight consists of a diglycidyl ether of bisphenol A. 17. Tubular sheet according to claim 12, characterized in that the diglycidyl ether of a lower molecular weight represents less than  <EMI ID = 138.1> 18. Tubular sheet according to any one of claims 12 to 14, characterized in that  <EMI ID = 139.1>  <EMI ID = 140.1> not polyglycidyl. 19. Tubular sheet according to any one of claims 1, 9 and 12, characterized in that the diglycidyl compounds represent approximately  <EMI ID = 141.1> polyglycidyl ic. 20. Tubular sheet according to claim 1, characterized in that the hardening agent comprises an agent increasing the viscosity and reacting with the glycidyl groups of the liquid resinous composition, in an amount sufficient to increase the viscosity of the liquid resinous composition in order to reduce the tendency of the charge to deposit, as well as a solidifying agent which reacts more slowly with the glycidyl groups of the liquid resinous composition than the viscosity-increasing agent, this solidifying agent being present in an amount sufficient to solidify this resinous composition liquid. 21. Tubular sheet according to claim 20, characterized in that the viscosity increasing agent is present in an amount sufficient to bring the viscosity of the liquid resinous composition  <EMI ID = 142.1> 22. Tubular sheet according to claim 20, characterized in that the viscosity increasing agent is present in an amount less than-  <EMI ID = 143.1> complete reaction with the giyciayie groups ae ia liquid resin composition. 23. Tubular sheet according to claim 22, characterized in that the viscosity increasing agent is present in an amount of about 10 to  <EMI ID = 144.1> glycidyl groups of the liquid resin composition. 24. Tubular sheet according to claim 23, characterized in that the viscosity increasing agent consists of a polyamine, a polyamide or a salt of a tertiary amine. 25. Tubular sheet according to claim 20, characterized in that the solidifying agent consists of a hardening agent based on imidazole having the following structure:  <EMI ID = 145.1> wherein R. represents a hydrogen atom, an alkyl group containing 1 to about 12 carbon atoms, a lower acyl group or a monocyclic or bicyclic aralkyl or aryl group containing 6 to about  <EMI ID = 146.1> each have a hydrogen atom, a halogen atom, a hydroxy group, a nitro group, an alkoxy group containing 1 to about 6 carbon atoms, an alkyl group containing 1 to about 12 carbon atoms, a lower acyl group or a monocyclic or bicyclic aralkyl or aryl group containing from 6 to about 15 carbon atoms. 26. Tubular sheet according to claim 25, characterized in that the hardening agent based on imidazole consists of 2-ethyl-4-m6thylimidazole. 27. Tubular sheet according to claim 20, characterized in that the solidifying agent consists of at least one compound chosen from methylene-dianiline and diphenylamine. 28. Tubular sheet according to any one of claims 20, 24, 25 and 27, characterized in that the molar ratio between the agent increasing the viscosity and the solidifying agent is between approximately 0.5: 1 and 2: 1. 29. Tubular sheet according to any one of claims 20 and 25, characterized in that the solidifying agent is catalytic and is used in an amount between approximately 0.01 and 0.5 mole per mole of glycidyl groups of the liquid resin composition. 30. Tubular sheet according to any one of claims 1, 12 and 20, characterized in that the viscosity of the liquid resinous composition is between approximately 1,000 and 7,000 centipoise at 25 [deg.] C. 31. Tubular sheet according to any one of claims 1, 12 and 20, characterized in that it consists of at least about 1,000 g of the solidified resinous composition. 32. Tubular sheet according to claim 1, characterized in that the hollow fiber membranes are arranged in a bundle, while the density factor of this bundle in this tubular sheet, based on the peripheral dimensions of this  <EMI ID = 147.1> 33. Tubular sheet according to claim 1, characterized in that it comprises a zone relatively free of hollow fiber membranes, as well as a zone comprising hollow fiber membranes. 34. Tubular sheet according to any one of claims 1, 12 and 20, characterized in that the average peripheral dimension around the  <EMI ID = 148.1> vis-à-vis the average peripheral dimension of the zone of the tubular sheet through which the bundle of hollow fiber membranes passes. 35. Tubular sheet according to claim 1, characterized in that it has, in cross section, an average dimension of about 0.05 to 1 m and a length of about 2 to 50 cm. 36. Tubular sheet according to claim 1, characterized in that the hollow fiber membranes have a diameter of between approximately 150 and 800 microns. 37. A method for forming a tubular sheet in which are coated several hollow fiber membranes suitable for the separation of fluids, this method consisting in introducing, into a mold, several hollow fiber membranes and a liquid resinous composition, then hardening this last, characterized in that the liquid resinous composition comprises: at. a resin having a viscosity of about 500 to 12,000 centipoise at 25 [deg.] C and containing a large amount by weight of a polyglycidyl resin having a viscosity of about 1,000 to 30,000 centipoi-  <EMI ID = 149.1> b. a curing agent composition in an amount sufficient to consume at least about  <EMI ID = 150.1> liquid; and vs. a charge of particles having a density of approximately 1 to 10 g per cm3 at 25 [deg.] C, particles with an average granularity of approximately 1.5 to 150 microns and a specific surface less than approximately 5 m2 / g, this filler representing approximately 5 to less than approximately 35% by volume of the liquid resinous composition, the latter having, at the temperature of the casting, a viscosity of approximately 500 to 5,000 centipoise. 38. Method according to claim 37, characterized in that the temperature of the liquid resin composition during the casting is between approximately 15 and 40 [deg.] C. 39. Method according to claim 37, characterized in that the tubular sheet is formed in a single casting. 40. The method of claim 39, characterized in that the amount of the liquid resin composition is at least about 1,000 g. 41. The method of claim 39, characterized in that the differences in maximum exothermic temperatures in the tubular sheet during curing are less than about 40 [deg.] C. 42. The method of claim 39, characterized in that the mold is isolated or heated to maintain the outer areas of the tubular sheet at about the same temperature as the inner areas of this sheet. 43. Method according to claim 37, characterized in that the hardening of the liquid resin composition is practically adiabatic. 44. Method according to any one of claims 39, 41 and 42, characterized in that the tubular sheet comprises an area relatively free of hollow fiber membranes, as well as an area comprising hollow fiber membranes. 45. Method according to claim 37, characterized in that the charge represents approximately 10 at 25% by volume of the liquid resinous composition. 46. Method according to claim 37, characterized in that the filler has a specific surface of approximately 0.1 to 2.5 m2 / g and particles with an average maximum granularity of approximately 2 to 100 microns. 47. Method according to claim 46, characterized in that the filler consists of a metal. 48. Method according to claim 46, characterized in that the filler consists of silica. 49. The method of claim 37, characterized in that the polyglycidyl resin consists of a glycidyl reaction product of a compound forming glycidyl groups and a compound  <EMI ID = 151.1> hydroquinone, phloroglucinol, 4,4'-dihydroxybenzophenone, 1,1-bis (4-hydroxyphenyl) ethane, bis (2-hydroxynaphthyl) methane, 2,2-bis (4-hydrophenyl) butane, 4,4'-dihydroxydiphenyl-sulfone, ethylene glycol, propylene glycol, butane-diol, pentanediol, isopentane-diol, linoleic acid dimer, poly (oxypropylene) glycol, 2,4 , 4'-trihydroxybisphé  <EMI ID = 152.1> 2,2'-tetra (p-hydroxyphenyl) ethane, phenol / formaldehyde novolak, o-cresol / formaldehyde novolak or a mixture of these compounds. 50. The method of claim 49, characterized in that the polyglycidyl resin consists of a glycidyl reaction product of a compound forming glycidyl groups and bisphenol A or phenol / formaldehyde novolak. 51. Method according to claim 50, characterized in that the polyglycidyl resin consists of a mixture of diglycidyl ethers of bisphenol A. 52. The method of claim 49, characterized in that the polyglycidyl resin comprises a large amount by weight of a diglycidyl ether having a weight average molecular weight of at least about 300, as well as a small amount by weight of an ether diglycidyl having a weight average molecular weight of less than about 2507 so that this polyglycidyl resin has a viscosity of about 4,000 to 25,000 centipoise at 25 [deg.] C. 53. The method of claim 52, characterized in that the diglycidyl ether of a higher molecular weight has a weight average molecular weight of about 300 to 600 and a viscosity of about 4,000 to 30,000 centipoise at 25 [deg. ]VS. 54. The method of claim 52, characterized in that the diglycidyl ether of a lower molecular weight has an average molecular weight in  <EMI ID = 153.1>  <EMI ID = 154.1> 55. Process according to claim 52, characterized in that the diglycidyl ether of a lower molecular weight consists of an alkyldiglycidyl ether of which the alkyl group contains 4 to 7 carbon atoms. 56. Process according to any one of claims 52, 54 and 55, characterized in that the diglycidyl ether of a higher molecular weight is the diglycidyl ether of bisphenol A. 57. Process according to claim 52, characterized in that the diglycidyl ether of a weight  <EMI ID = 155.1> by weight of the polyglycidyl resin. 58. Process according to claim 52, characterized in that the diglycidyl ether of a weight  <EMI ID = 156.1> weight of the glycidyl resin. 59. Method according to claim 37, characterized in that the hardening agent consists of an agent increasing the viscosity and reacting with the glycidyl groups of the liquid resinous composition, this agent increasing the viscosity being present in an amount sufficient to increase the viscosity of this liquid resinous composition in order to reduce the tendency of the charge to deposit, as well as of a solidifying agent reacting more slowly with the glycidyl groups of the liquid resinous composition than the viscosity increasing agent, this solidifying agent being present in an amount sufficient to solidify this liquid resinous composition. 60. A method according to claim 59, characterized in that the curing temperature is raised by at least about 5 [deg.] C to initiate the reaction of the solidifying agent. 61. Method according to claim 59, characterized in that the viscosity-increasing agent is present in an amount sufficient to bring the viscosity of the liquid resinous composition to at least  <EMI ID = 157.1> 62. Method according to claim 59, characterized in that the agent increasing the viscosity  <EMI ID = 158.1> molars of that required to ensure complete reaction with the glycidyl groups of the liquid resinous composition. 63. Method according to claim 59, characterized in that the agent increasing the viscosity  <EMI ID = 159.1> that required for reaction with the glycidyl groups of the liquid resin composition. 64. Method according to claim 63, characterized in that the viscosity-increasing agent consists of a polyamine, a polyamide or a salt of a tertiary amine. 65. Method according to claim 59, characterized in that the solidifying agent consists of a hardening agent based on imidazole having the / &#65533; structure:  <EMI ID = 160.1> in which R1 represents a hydrogen atom, a  <EMI ID = 161.1> bone, a lower acyl group or a monocyclic or bicyclic aralkyl or aryl group containing 6 to 3-  <EMI ID = 162.1> each represents a hydrogen atom, a halogen atom, a hydroxy group, a nitro group, an alkoxy group containing 1 to about 6 carbon atoms, an alkyl group containing 1 to about 12 carbon atoms, a lower acyl group or a monocyclic or bicyclic aralkyl or aryl group containing 6 to about 15 carbon atoms. 66. Method according to claim 65. characterized in that the hardening agent based on imidazole consists of 2-ethyl-4-methylimidazole. 67. Process according to claim 59, characterized in that the solidifying agent consists of Eu at least one compound chosen from methylenedianiline and diphenylamine. 68. Method according to any one of claims 59, 64, 65 and 67, characterized in that the molar ratio between the viscosity increasing agent and the solidifying agent is between approximately 0.5: 1 and 2: 1 . 69. A method according to any one of claims 59 and 65, characterized in that the solidifying agent is catalytic and used in an amount between about 0.01 and 0.5 mole per mole of glycidyl groups of the liquid resinous composition . 70. Method according to any one of claims 37, 52 and 59, characterized in that the viscosity of the liquid resin composition at the casting temperature is approximately 1,000 to 4,000 centipoise. 71. A method according to any one of claims 37, 52 and 59, characterized in that the temperature of the resin is raised after solidification in order to ensure additional crosslinking.