GB1595299A - Non-woven fabrics - Google Patents
Non-woven fabrics Download PDFInfo
- Publication number
- GB1595299A GB1595299A GB50215/77A GB5021577A GB1595299A GB 1595299 A GB1595299 A GB 1595299A GB 50215/77 A GB50215/77 A GB 50215/77A GB 5021577 A GB5021577 A GB 5021577A GB 1595299 A GB1595299 A GB 1595299A
- Authority
- GB
- United Kingdom
- Prior art keywords
- fibres
- fabric
- bonding
- membrane
- wet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000004745 nonwoven fabric Substances 0.000 title description 10
- 239000004744 fabric Substances 0.000 description 21
- 239000012528 membrane Substances 0.000 description 19
- 238000000034 method Methods 0.000 description 11
- 239000000203 mixture Substances 0.000 description 6
- 229920001169 thermoplastic Polymers 0.000 description 6
- 239000004416 thermosoftening plastic Substances 0.000 description 6
- 229920000728 polyester Polymers 0.000 description 5
- 239000004743 Polypropylene Substances 0.000 description 3
- 239000000969 carrier Substances 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 238000007596 consolidation process Methods 0.000 description 3
- -1 polypropylene Polymers 0.000 description 3
- 229920001155 polypropylene Polymers 0.000 description 3
- 239000004962 Polyamide-imide Substances 0.000 description 2
- 239000004760 aramid Substances 0.000 description 2
- 229920003235 aromatic polyamide Polymers 0.000 description 2
- 238000003490 calendering Methods 0.000 description 2
- 229920002301 cellulose acetate Polymers 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 230000004927 fusion Effects 0.000 description 2
- 238000009828 non-uniform distribution Methods 0.000 description 2
- 229920002312 polyamide-imide Polymers 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000000721 bacterilogical effect Effects 0.000 description 1
- 238000009960 carding Methods 0.000 description 1
- 230000001112 coagulating effect Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 238000001223 reverse osmosis Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000004753 textile Substances 0.000 description 1
- 238000000108 ultra-filtration Methods 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
- 239000002759 woven fabric Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/10—Supported membranes; Membrane supports
- B01D69/107—Organic support material
- B01D69/1071—Woven, non-woven or net mesh
-
- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
- D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
- D04H1/54—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H5/00—Special paper or cardboard not otherwise provided for
- D21H5/12—Special paper or cardboard not otherwise provided for characterised by the use of special fibrous materials
- D21H5/20—Special paper or cardboard not otherwise provided for characterised by the use of special fibrous materials of organic non-cellulosic fibres too short for spinning, with or without cellulose fibres
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Nonwoven Fabrics (AREA)
- Paper (AREA)
- Laminated Bodies (AREA)
Description
(54) NON-WOVEN FABRICS
(71) We, CARL FREUDENBERG, a
German Company (a Kommanditgesellschaft the present personally responsible partners of which are HELMET FABRICIUS,
HANS ERICH FREUDENBERG, OTTO SCHILD
HAUER, HERMAN FREUDENBERG, DIETER
FREUDENBERG and REINHART FREUDEN ERG), of 6940 Weinheim Bergstrasse,
Hohnerweg 2, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement: Semi-permeable membranes are used for, for example, ultra--filtration and reverse osmosis. They are generally used in tubular or flat form. They are structurally weak and so are supported by supporting elements often comprising tubes or plates, for example steel or PVC tubes or plastics plates, that are perforated or provided with channels or ducts for the removal of liquid.
The supporting elements are sometimes subjected to high pressure (for example 1 to 140 bars) and so for strength reasons the distances between the perforations or channels must be quite large. A carrier for the semi-permeable membrane is usually therefore positioned between the plate or tube and the membrane. This carrier must be porous and must serve as the drainage and supporting layer and be substantially incompressible.
The semi-permeable membrane is often formed on the carrier. The membrane usually consists of cellulose acetate and may be formed by extruding cellulose acetate onto the carrier in a coating thickness of 100 to 200 ,um and then coagulating the coated material to forrn the membrane with a coating thickness generally of 500 to 500Q angstroms.
It is necessary for the permeation properties of the membrane that the membrane should be of uniform thickness and so it is necessary that the carrier should have as smooth a surface as possible.
Although textile carriers are known, all suffer from some disadvantages, generally involving irregularities of the surface, in the,micro range. Thus woven fabrics have a surface structure that is sufficiently rough that it is reproduced in the membrane, and can often result in hairline cracks, and thus destruction, of the membrane. Cellulosic papers may be smoother but suffer from bacteriological contamination.
Recently non-woven fabrics have been used widely, generally consisting of thermoplastic fibres, especially polyester or polypropylene, and made by a dry-lay method followed by consolidation with heat and pressure. An important disadvantage of the dry-laid products is their non-uniform structure, in that they tend to have an unsatisfactory distribution of individual fibres and tend to have a rough surface. The dry-lay method may involve carding but if it involves cross-lapping then there may additionally be the problem of a nonuniform distribution of weight and thickness across the width of the fabric. This problem can be reduced by combining cross-laid with longitudinally-laid nonwovens and by using especially shaped calender rolls that bulge so as to give greater pressure at the centre of the fabric width than at the outside. However this difficulty cannot be solved completely in this manner and the best product that can be made by this method tends to have higher weights and smaller thicknesses in the edge region, with the result that the finally produced membrane has nonuniform thickness and thus non-uniform properties. Accordingly, at present, wide marginal zones of the fabric have to be rejected before or after coating with the membrane.
Greater uniformity across the width can be achieved using air-laying techniques but the resultant fabrics have an even more non-unifonn structure owing to nonuniform distribution of fibres so that the surface is rougher and the thickness of the membrane more variable.
All existing methods therefore involve considerable wastage and necessitate extensive checking steps.
According to the present invention, a permeable bonded non-woven fabric, suitable for use as a carrier for a semipermeable membrane, has been prepared by wet-laying a mixture lof fibres consisting substantially only of synthetic nonbonding fibres having a size of from 1 to 7 dtex and synthetic thermoplastic bonding fibres having a size of from 4 to 30 dtex, thereby obtaining a wet-laid non-woven fabric having the highest concentration of bonding fibres at one surface of the fabric, and heat-bonding the wet-laid fabric.
The non-bonding fibres in )a non-woven fabric according to the invention can have an orientation corresponding substantially to that of a wet-laid non-woven and are bonded to each other by the thermoplastic bonding fibres. Although the concentration of the bonding fibres is greatest at one surface of the fabric, this need not substantially reduce the permeability of the fabric. Accordingly, the fabrics of the invention are suitable for use as a carrier for a semi-permeable membrane.
The wet-lay process used in the invention may involve conventional consolidation techniques, for example, hot calendering. The fabric deposited by the wet-lay method may be, for example, 150 ,u.m thick.
The thermoplastic bonding fibres will usually comprise at least 10% by weight of the mixture of bonding fibres and nonbonding fibres. The bonding fibres may be staple or cut fibres; they are {preferably from 6 to 35 mm, and most preferably about 12 mm, long. The non-bonding fibres may ibe staple or cut fibres; they are preferably 3 to 18 mm, and most preferably about 6 mm, long. The size of the bonding fibres is most preferably about 6.8 dtex, while that of the non-bonding fibres is most preferably 1.3 to 3.3 dtex.
Suitable bonding fibres include unstretched . polyester fibres and/or polypropylene fibres. Suitable non-bonding fibres include stretched polyester fibres, polyamide imide fibres and aromatic polyamide fibres.
The wet-lay and consolidation techniques utilised can easily be operated to produce a fabric having a very fine-structured and even surface heavily permeated and bonded by fusion of the thermoplastic bonding fibres. The fusion is generally brought about by hot calendering. The product can easily be made to have better and more uniform distribution of weight and thickness across its width than the conventional non-wovens used as carriers for semi-permeable membranes. For instance, it is easily possible to obtain variations in weight and thickness of + 1%. The fibrous structure, e.g. the distribution of the individual fibres, is similarly better than with conventional dry-laid non-woven carriers.
Further, the surface can be smoother than with such fabrics. The products can have good isotropic high strength.
Because of the greater uniformity and smoothness, the subsequent application of the membrane onto the surface can be carried out more easily to obtain a more uniform product, and many of the checks that had to be made previously can be eliminated.
A particular advantage of the invention is that it is easily possible to vary the composition of the ;fabric so that it can have a wide variety of properties, for example, by appropriate choice of the fibre mixture.
Particularly preferred methods of making bonded fabrics, which are applicable in the present invention, are described, exemplified and claimed in our copending Application No. 50217/77 (Serial No. 1595300).
WHAT WE CLAIM IS:
1. A permeable bonded non-woven fabric, suitable for use as a carrier for a semi-permeable membrane, which has been prepared by wet-laying a mixture of fibres consisting substantially only of synthetic non-bonding fibres having a size of from 1 to 7 dtex and synthetic thermoplastic bonding fibres having a size of from 4 to 30 dtex, thereby obtaining a wet-laid nonwoven fabric having the highest concentration of bonding fibres at one surface of the fabric, and heat-bonding the wet-laid fabric.
2. A fabric according to claim 1 which comprises at least 10%, by weight of the weight of the mixture, bonding fibres which are 6 to 36 mm. long, and in which the non-bonding fibres are 3 to 18 mm. long.
3. A fabric according to claim 1 of claim 2 in which the bonding fibres comprise unstretched polyester fibres and/or polypropylene fibres.
4. A fabric according to any preceding claim in which the non-bonding fibres comprise fibres selected from polyamide imide fibres, aromatic polyamide fibres and stretched polyester fibres.
5. A fabric according to claim 1 substantially as herein described.
6. A semi-permeable membrane coated on a fabric according to any preceding
Claims (1)
- claim.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2655014A DE2655014C3 (en) | 1976-12-04 | 1976-12-04 | Carrier layer for semi-permeable membranes |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1595299A true GB1595299A (en) | 1981-08-12 |
Family
ID=5994671
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB50215/77A Expired GB1595299A (en) | 1976-12-04 | 1977-12-02 | Non-woven fabrics |
Country Status (12)
| Country | Link |
|---|---|
| JP (1) | JPS5370986A (en) |
| AT (1) | AT367312B (en) |
| AU (1) | AU516289B2 (en) |
| CA (1) | CA1107580A (en) |
| DE (1) | DE2655014C3 (en) |
| DK (1) | DK148786C (en) |
| FR (1) | FR2372922A1 (en) |
| GB (1) | GB1595299A (en) |
| IL (1) | IL53455A0 (en) |
| NL (1) | NL185163C (en) |
| SE (1) | SE433505B (en) |
| ZA (1) | ZA776021B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2195366A (en) * | 1986-09-11 | 1988-04-07 | Kendall & Co | Porous fabrics |
| EP2659955A4 (en) * | 2010-12-27 | 2016-11-02 | Hokuetsu Kishu Paper Co Ltd | Wet-laid nonwoven fabric for semipermeable membrane supporting body, method for producing said wet-laid nonwoven fabric, and method for identifying low-density defect of wet-laid nonwoven fabric |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5417383A (en) * | 1977-07-11 | 1979-02-08 | Toray Ind Inc | Separating unit for liquid |
| JPS61222506A (en) * | 1985-03-29 | 1986-10-03 | Japan Vilene Co Ltd | Semipermeable membrane support and its preparation |
| EP0253047A1 (en) * | 1986-07-14 | 1988-01-20 | VOGELBUSCH GESELLSCHAFT m.b.H. | Membrane-separation element |
| WO1998004233A1 (en) * | 1996-07-31 | 1998-02-05 | The Procter & Gamble Company | Conditioning shampoo compositions comprising polyalkoxylated polyalkyleneamine |
| JP5216924B1 (en) * | 2012-01-30 | 2013-06-19 | 北越紀州製紙株式会社 | Nonwoven fabric for semipermeable membrane support |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1137457A (en) * | 1954-08-07 | 1957-05-29 | Process for the manufacture of papers and films starting from polyolefins | |
| GB1099534A (en) * | 1965-05-26 | 1968-01-17 | Ici Ltd | Fibrous, non-woven sheet materials |
-
1976
- 1976-12-04 DE DE2655014A patent/DE2655014C3/en not_active Expired
-
1977
- 1977-10-07 ZA ZA00776021A patent/ZA776021B/en unknown
- 1977-11-03 NL NLAANVRAGE7712123,A patent/NL185163C/en not_active IP Right Cessation
- 1977-11-11 JP JP13484377A patent/JPS5370986A/en active Pending
- 1977-11-23 IL IL53455A patent/IL53455A0/en not_active IP Right Cessation
- 1977-12-01 SE SE7713646A patent/SE433505B/en not_active IP Right Cessation
- 1977-12-02 DK DK539877A patent/DK148786C/en active
- 1977-12-02 GB GB50215/77A patent/GB1595299A/en not_active Expired
- 1977-12-02 AU AU31173/77A patent/AU516289B2/en not_active Expired
- 1977-12-02 AT AT0865777A patent/AT367312B/en not_active IP Right Cessation
- 1977-12-02 FR FR7736383A patent/FR2372922A1/en active Granted
- 1977-12-05 CA CA292,431A patent/CA1107580A/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2195366A (en) * | 1986-09-11 | 1988-04-07 | Kendall & Co | Porous fabrics |
| GB2195366B (en) * | 1986-09-11 | 1991-01-09 | Kendall & Co | Porous fabrics |
| EP2659955A4 (en) * | 2010-12-27 | 2016-11-02 | Hokuetsu Kishu Paper Co Ltd | Wet-laid nonwoven fabric for semipermeable membrane supporting body, method for producing said wet-laid nonwoven fabric, and method for identifying low-density defect of wet-laid nonwoven fabric |
| US10443167B2 (en) | 2010-12-27 | 2019-10-15 | Hokuetsu Corporation | Method for producing a wet-laid nonwoven fabric |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5370986A (en) | 1978-06-23 |
| AU516289B2 (en) | 1981-05-28 |
| FR2372922B1 (en) | 1982-04-09 |
| DE2655014B2 (en) | 1979-01-04 |
| SE433505B (en) | 1984-05-28 |
| IL53455A0 (en) | 1978-01-31 |
| NL185163C (en) | 1990-02-01 |
| CA1107580A (en) | 1981-08-25 |
| ATA865777A (en) | 1981-11-15 |
| SE7713646L (en) | 1978-06-05 |
| DK539877A (en) | 1978-06-05 |
| ZA776021B (en) | 1978-05-30 |
| NL7712123A (en) | 1978-06-06 |
| FR2372922A1 (en) | 1978-06-30 |
| AU3117377A (en) | 1979-06-07 |
| AT367312B (en) | 1982-06-25 |
| DK148786C (en) | 1986-03-03 |
| NL185163B (en) | 1989-09-01 |
| DE2655014A1 (en) | 1978-06-08 |
| DK148786B (en) | 1985-09-30 |
| DE2655014C3 (en) | 1979-09-06 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19921202 |