Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D39/00—Filtering material for liquid or gaseous fluids
  • B01D39/08—Filter cloth, i.e. woven, knitted or interlaced material
  • B01D39/086—Filter cloth, i.e. woven, knitted or interlaced material of inorganic material
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
  • A62B17/00—Protective clothing affording protection against heat or harmful chemical agents or for use at high altitudes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D39/00—Filtering material for liquid or gaseous fluids
  • B01D39/14—Other self-supporting filtering material ; Other filtering material
  • B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
  • B01D39/2055—Carbonaceous material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D39/00—Filtering material for liquid or gaseous fluids
  • B01D39/14—Other self-supporting filtering material ; Other filtering material
  • B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
  • B01D39/2055—Carbonaceous material
  • B01D39/2065—Carbonaceous material the material being fibrous
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/02—Types of fibres, filaments or particles, self-supporting or supported materials
  • B01D2239/0241—Types of fibres, filaments or particles, self-supporting or supported materials comprising electrically conductive fibres or particles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/04—Additives and treatments of the filtering material
  • B01D2239/0471—Surface coating material
  • B01D2239/0478—Surface coating material on a layer of the filter
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
  • B01D2239/065—More than one layer present in the filtering material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
  • B01D2239/065—More than one layer present in the filtering material
  • B01D2239/0659—The layers being joined by needling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
  • B01D2239/065—More than one layer present in the filtering material
  • B01D2239/0681—The layers being joined by gluing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/10—Filtering material manufacturing

Definitions

• the invention relates to the manufacture of shaped filter parts having adsorbent properties through the use of activated carbon fibers.
• shaped filter pieces is meant here self-supporting pieces having non-planar shapes.
• the invention relates in particular to the production of shaped pieces of clothing, for example gloves, socks, underwear, hats, ... intended for civilian or military personnel to protect them against attacks, in particular nuclear, bacterial or chemical.
• the method according to the invention can however be used in other applications, for example for producing filter parts having particular shapes, such as sleeves, caps, or the like.
• Activated carbon fabrics are known and used for filtration applications.
• Documents FR 2 741 363 A and WO 98/41678 A describe the production of such fabrics.
• making shaped pieces from these fabrics requires a sewing operation.
• seams made on an activated carbon fabric locally increase the stiffness significantly, creating discomfort.
• the seams create preferential passages for the toxic substances to be retained by generating a heterogeneity of porosity.
• the object of the present invention is to provide a method for making shaped filter parts, in particular, but not exclusively, parts of NBC protective clothing, without encountering the aforementioned drawbacks. More particularly, the invention aims to obtain such shaped filter parts made entirely of activated carbon fibers, so that they are washable, thermally stable and capable of retaining good adsorption properties in a humid environment, while having intrinsically good mechanical strength and offering a porosity free of preferential passages for the medium to be filtered.
• the invention is remarkable in that the filtering part is obtained directly after carbonization and activation of a preform made of carbon precursor fibers having been, by a textile process, put into a shape corresponding to that of the part to be manufactured.
• the textile process for shaping the preform can be at least partly knitting, two-dimensional texture stitching or braiding.
• two-dimensional texture is meant here in particular a multidirectional fabric or tablecloth.
• the preform is produced in particular in a texture of cellulose fibers, for example rayon fibers, which makes it possible to obtain a large specific surface, for example greater than 800 m 2 / g, or even greater than 1200 m 2 / g, and high purity of carbon fibers.
• the carbonization and activation treatment comprises:
• a carbonization step comprising a heat treatment optionally under an inert atmosphere up to a temperature between 250 ° C and 500 ° C, and
• the carbonization and activation treatment comprises: a step of impregnating the preform with a composition containing at least one constituent having a function of promoting the decomposition of cellulose, and
• the invention also relates to a piece of clothing as it can be obtained by the process, that is to say a piece of clothing in shape, characterized in that it is produced in a single piece of coherent texture consisting of activated carbon fibers.
• a piece of clothing is remarkable in that it inherently has the necessary strength for its use, while being formed of activated carbon fibers.
• the parts according to the invention have good fire resistance characteristics and are thermostable. Thanks to the conductivity of carbon fibers, they allow the evacuation of static electricity. They are moreover easily washable. Compared to activated carbon particles, activated carbon fiber parts have a very limited loss of performance due to humidity. The porosity of activated carbon fibers indeed has a large majority of micropores which are not capable of filling with water by capillarity. In addition, because of their size much smaller than that of activated carbon particles, the activated carbon fibers provide the gas flow, with equal mass, with a much greater external surface. At identical performance, the thickness of the parts can therefore be greatly reduced.
• FIG. 2 shows the successive steps of a method according to a variant of the embodiment of Figure 1; and FIG. 3 shows respective photographs of a glove preform knitted with a viscose yarn, and of the glove made of activated carbon fibers obtained after carbonization treatment and activation of the preform.
• a first step 10 of the method of FIG. 1 consists in making a preform of a part to be manufactured, using a textile confection process.
• the preform is produced from carbon precursor fibers which are formed into threads or yarns.
• precursors can be used such as preoxidized polyacrylonitrile (PAN), pitches, phenolic compounds.
• PAN preoxidized polyacrylonitrile
• pitches pitches
• phenolic compounds phenolic compounds
• a cellulosic precursor is used, in particular a viscose, for example rayon.
• the preform is put into a shape corresponding to that of the part to be manufactured, while taking account of the shrinkages occurring during the carbonization and activation treatment.
• the shaping can be carried out directly from threads or spun into carbon precursor fibers, in particular by knitting or by braiding. It is also possible to first produce a two-dimensional texture from the threads or yarns made of carbon precursor fibers, for example a fabric or a multidirectional sheet, then to shape the preform by cutting and sewing with a thread of the same type. nature.
• a multidirectional ply is formed by superposition of several unidirectional plies made up of threads or yarns extending parallel to the same direction. The unidirectional layers are superimposed with different directions and possibly linked to each other for example by sewing or by light needling.
• a second step 20 of the process consists in carbonizing the preform.
• Carbonization comprises a heat treatment phase in an inert atmosphere at a temperature between 250 ° C and 500 ° C, for example approximately equal to 400 ° C, this phase being carried out with a slow rise in temperature, typically between 0.01 ° C / min and 0.5 ° C / min, and over a relatively long period of several days to several weeks.
• a final heat treatment phase at a higher temperature can then be carried out, for example up to 600 ° C. to 900 ° C., also under an inert atmosphere, for a much shorter duration, for example a few minutes.
• a third step 30 of the process consists in activating the carbon fiber preform obtained. Activation is carried out by heat treatment of the carbon fiber preform under an oxidizing atmosphere, such as water vapor or preferably carbon dioxide or a mixture of carbon dioxide and water vapor. Reference may be made to the document FR 2 741 363 A already cited.
• the heat treatment temperature is between 750 ° C and 950 ° C, preferably between 850 ° C and 950 ° C and its duration is preferably between 50 min and 300 min depending on the specific surface desired. It is thus possible to obtain a part made of activated carbon fibers having a specific surface greater than 800 m 2 / g, even at 1200 m 2 / g.
• a final post-processing step 40 can possibly be carried out, depending on the use envisaged for the part.
• a post-treatment can consist in forming a very fine deposit to fix possible carbon particles and to prevent their departure during use of the room. This deposit can be formed by spraying elastomer or latex.
• Another type of post-treatment can consist in associating with the piece a lining which has the function not to give a hold to the piece, but to avoid direct contact between it and the skin of the user.
• the lining can be ventilated, so as not to affect porosity and permeability and be connected very punctually to the part, for example by gluing.
• FIG. 2 illustrates an alternative embodiment of the method which can be used with a preform of cellulose precursor fibers.
• This variant differs from the process of FIG. 1 in that steps 20 and 30 of carbonization and activation are replaced by a step 20 ′ of impregnating the preform with a composition containing a constituent which promotes the dehydration of cellulose and a heat treatment step 30 'allowing the part to be obtained directly in activated carbon fibers.
• the impregnation is carried out with a composition containing at least one constituent which promotes the dehydration of cellulose, such as a mineral constituent chosen from phosphoric acid, zinc chloride, potassium sulphate, potassium hydroxide, diammonium phosphate and ammonium chloride.
• a composition containing phosphoric acid so that the mass of acid fixed on the preform is between 10 and 22% of the mass of the dry preform.
• the heat treatment comprises a rise in temperature at a speed of between 1 ° C / min and 15 ° C / min, followed by a level preferably carried out at a temperature between 350 ° C and 500 ° C under an inert atmosphere or under atmosphere containing a reaction activator such as carbon dioxide or water vapor.
• the part obtained is then preferably washed.
• a reaction activator such as carbon dioxide or water vapor.
• Example 1 Glove preforms such as that shown on the left in the photograph in FIG. 3 are produced by knitting at the point of Jersey of a 330 dtex rayon thread, the edges of the gloves being made with a 167 dtex rayon thread.
• the preforms are placed on racks in an oven and heat treated for about 2 weeks.
• the rate of temperature rise is very low, less than 0.1 ° C / min, up to a level approximately equal to 400 ° C.
• the preforms obtained are then heat treated again to a temperature of approximately 700 ° C, for a period of approximately 15 min, so as to stabilize the carbon network.
• Activation of the carbonized preforms is carried out in a rotary autoclave oven, at a temperature of approximately 850 ° C., under an atmosphere of carbon dioxide (CO 2 ) for a period of approximately 1 h.
• the gloves obtained are like the one shown in the photo in Figure 3 (right). They have the following average characteristics:
• the shrinkage caused by carbonization and activation is on average 32%. It is this shrinkage that is taken into account to produce preforms giving gloves of desired sizes.
• the shrinkage is not necessarily uniform throughout the room and in all directions.
• the shape to be given to the preform is preferably determined by tests, which can allow simulation models to be produced.
• the glove made of activated carbon fibers can be put on an under-glove, for example in cotton canvas. A point bond with a few dots of glue between the underglove and the glove can be made. The assembly obtained can be directly inserted into an over-glove, for example leather. In operation, only the sub-assembly formed by the glove in activated carbon fibers and the possible glove is consumable. It is also easily incinerable without releasing toxic effluents.
• Glove preforms such as those of Example 1 are impregnated by immersion in a solution of phosphoric acid H 3 PO at 20% by volume in water.
• the impregnated preforms are steamed at a temperature between 70 ° C and 90 ° C to remove the water, the quantity of phosphoric acid fixed on the preforms representing approximately 16% by mass relative to the mass of the dry preforms.
• the preforms are then admitted continuously into a heat treatment oven in which they pass by, being supported by a fabric, for example made of glass fibers.
• the heat treatment includes a rise in temperature at a speed of approximately 5 ° C / min, followed by a plateau at a temperature of approximately 200 ° C.
• the heat treatment is carried out under an internal atmosphere (nitrogen) for a total duration of approximately 90 min.
• the gloves obtained are washed with demineralized water at a temperature of around 90 ° C.
• the measured shrinkage is on average 28%.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Health & Medical Sciences (AREA)
• Geology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Toxicology (AREA)
• Textile Engineering (AREA)
• Engineering & Computer Science (AREA)
• Inorganic Chemistry (AREA)
• General Health & Medical Sciences (AREA)
• Business, Economics & Management (AREA)
• Emergency Management (AREA)
• Inorganic Fibers (AREA)
• Knitting Of Fabric (AREA)
• Woven Fabrics (AREA)
• Filtering Materials (AREA)
• Professional, Industrial, Or Sporting Protective Garments (AREA)

Priority Applications (8)

Applications Claiming Priority (3)

Publications (1)

Family

ID=26212277

Family Applications (1)

Country Status (10)

Cited By (4)

Families Citing this family (11)

Citations (5)

Family Cites Families (12)

• 2000
  • 2000-03-22 FR FR0003638A patent/FR2806640B1/fr not_active Expired - Fee Related
• 2001
  • 2001-03-21 RU RU2002124859/12A patent/RU2233696C2/ru not_active IP Right Cessation
  • 2001-03-21 EP EP01917195A patent/EP1265688B1/fr not_active Expired - Lifetime
  • 2001-03-21 CN CNB018068278A patent/CN1189231C/zh not_active Expired - Fee Related
  • 2001-03-21 ES ES01917195T patent/ES2329758T3/es not_active Expired - Lifetime
  • 2001-03-21 US US10/239,130 patent/US20030032556A1/en not_active Abandoned
  • 2001-03-21 JP JP2001568558A patent/JP2003527240A/ja active Pending
  • 2001-03-21 HK HK03104381.6A patent/HK1052890B/zh not_active IP Right Cessation
  • 2001-03-21 DE DE60139188T patent/DE60139188D1/de not_active Expired - Lifetime
  • 2001-03-21 WO PCT/FR2001/000835 patent/WO2001070372A1/fr not_active Ceased

Patent Citations (6)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events