Classifications

• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M13/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment
  • D06M13/244—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with compounds containing sulfur or phosphorus
  • D06M13/282—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with compounds containing sulfur or phosphorus with compounds containing phosphorus
  • D06M13/292—Mono-, di- or triesters of phosphoric or phosphorous acids; Salts thereof
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M11/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising
  • D06M11/68—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with phosphorus or compounds thereof, e.g. with chlorophosphonic acid or salts thereof
  • D06M11/70—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with phosphorus or compounds thereof, e.g. with chlorophosphonic acid or salts thereof with oxides of phosphorus; with hypophosphorous, phosphorous or phosphoric acids or their salts
  • D06M11/71—Salts of phosphoric acids
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31855—Of addition polymer from unsaturated monomers
  • Y10T428/31938—Polymer of monoethylenically unsaturated hydrocarbon
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
  • Y10T442/20—Coated or impregnated woven, knit, or nonwoven fabric which is not [a] associated with another preformed layer or fiber layer or, [b] with respect to woven and knit, characterized, respectively, by a particular or differential weave or knit, wherein the coating or impregnation is neither a foamed material nor a free metal or alloy layer
  • Y10T442/2139—Coating or impregnation specified as porous or permeable to a specific substance [e.g., water vapor, air, etc.]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
  • Y10T442/20—Coated or impregnated woven, knit, or nonwoven fabric which is not [a] associated with another preformed layer or fiber layer or, [b] with respect to woven and knit, characterized, respectively, by a particular or differential weave or knit, wherein the coating or impregnation is neither a foamed material nor a free metal or alloy layer
  • Y10T442/2418—Coating or impregnation increases electrical conductivity or anti-static quality
  • Y10T442/2451—Phosphorus containing
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
  • Y10T442/20—Coated or impregnated woven, knit, or nonwoven fabric which is not [a] associated with another preformed layer or fiber layer or, [b] with respect to woven and knit, characterized, respectively, by a particular or differential weave or knit, wherein the coating or impregnation is neither a foamed material nor a free metal or alloy layer
  • Y10T442/2861—Coated or impregnated synthetic organic fiber fabric
  • Y10T442/291—Coated or impregnated polyolefin fiber fabric

Definitions

• a solution of polymer is flash-spun at a temperature above the boiling point of the solvent and at a high pressure into a low pressure area, whereupon a three-dimensional network of filmfibrils forms at the spinneret.
• the network is spread by means of a baffle and is then collected in multidirectional, overlapping, and intersecting arrangement on a moving belt.
• the sheet may be consolidated by passing it through the nip of .a pair of cold rolls.
• a hot embossing process for improving the delamination and abrasion resistance of such sheets while retaining the softenability of the sheet is also known.
• Such nonwoven products exhibit desirable combinations of softness, drape, breatheability, etc., which has led to their acceptance for use in disposable or limited-use garments, as protective wrapping materials, drapes and curtains, etc.
• the ability to function as a barrier to liquid water while still permitting passage of water vapor results from the film-fibril structure of the nonwoven sheet which permits passage of water (and other gaseous) vapor through the tortuous paths from one surface of the sheet to the opposite surface provided by the microscopic channels between the relatively close packed film-fibril elements, while liquid water is precluded from penetrating these same channels due to their small size and the hydrophobic character of the polyoletinpolymer surface.
• the relative freedom for passage of vapor through the nonwoven sheets can be varied over a substantial range, depending on how tightly compacted (how highly'calendered or embossed) the sheets may be, whether subsequent to bonding or embossing the sheet has been mechanically worked to loosen up the film-fibril structure between bond points, and: on the total basis weight of the sheet etc. In any event, the water barrier property continues to be exhibited, provided the nonwoven sheet remains free from gross holes as might be deliberately introduced.
• nonwoven fibrous sheets having vapor transmission and liquid water barrier properties have obvious potential utility in a multitude of applications, e.g., disposable, protective garments such as surgeons gowns; protective wrap for various commodities such as carpets, fiber bales, lumber, grain, etc.'; sterile packaging permeable tosterilizing gases but impermeable to bacteriaor liquids; consumer products suchas wind breakers, rainwear, sleeping bag liners, etc.
• water barrier properties have obvious potential utility in a multitude of applications, e.g., disposable, protective garments such as surgeons gowns; protective wrap for various commodities such as carpets, fiber bales, lumber, grain, etc.'; sterile packaging permeable tosterilizing gases but impermeable to bacteriaor liquids; consumer products suchas wind breakers, rainwear, sleeping bag liners, etc.
• the wellknownlpropensity ofpolyolefin articles to accumulate static chargesisadisadvantage Unfortunately, the conventionaltechnique of simply applying antistat finishes to the nonwoven sheets does not
• the present invention concerns a nonwoven sheet comprised of film-fibril elements of an olefin polymer which sheet bears at least 0.1 percent by weight, preferably at least 0.3 percent by weight of a non-rewettable finish agent defined by the formula: M,,R;,-,,PO where M is selected from the group consisting of lithium, sodium, potassium, and ammonium ions, R represents an alkyl group containing 3 to 5 carbon atoms, and n is selected from the integers l and 2.
• M is selected from the group consisting of lithium, sodium, potassium, and ammonium ions
• R represents an alkyl group containing 3 to 5 carbon atoms
• n is selected from the integers l and 2.
• the preferred agents are those where M represents the potassium ion, and the most highly preferred finish is a mixture of approximately equimolar quantities of the two agents potassium dibutyl phosphate and dipotassium butyl phosphate.
• the preferred polyolefin is linear polyethylene. It is preferred that at least 0.3 percent but no more than about 2 percent by weight of agent be present on the sheet. Excessive amounts of agent are not only unwarranted for economic reasons but are also undesirable because the water barrier properties of the sheet are adversely affected. 1 i
• the antistat finish of this invention may be applied to the polyolefin nonwoven sheets by immersing the sheet in an aqueous solution of the agent; by kiss-roll, gravure roll, or similar application of a coating of an aqueous solution of the agent; or by spraying an aqueous solution of the agent onto the surface of the sheet.
• a third component such as a non-rewettable surfactant or a volatile alcohol.
• the nonwoven fibrous sheets useful for this invention may be prepared from any crystalline olefin polymer but linear (high density) polyethylene is the preferred polyolefin; They are composed of film-fibril elements having a: surface area greater than 2 meter lgm. and may be produced by a flashextrusion method as dis closed in US. Pat. No. 3,169,899.
• the nonwoven sheets may be cold consolidated as described in said US. Pat. No. 3,169,899, or point embossed as disclosed in US. Pat. No. 3,478,141, or surface bonded type as disclosed inIlS. Pat. No. 3,442,740.
• the operable agents for the finish/coatings of the present invention possess a critical balance of high antistat activity and moderate aqueous surfactant power.
• the mono and dialkyl phosphates wherein the alkyl group contains 3 to 5 carbon'ato'ms i.e., n-propyl, isopropyl, n-butyl, isobutyl, secondary butyl, tertiary butyl, n-amyl, andthe various C alkyl isomers
• the antistat agent must exhibit a certain level of aqueous surfactant power. If the antistat is too good a surfactant, then when the coated nonwoven sheet subsequently comes adventitiously in contact with water, a quantity of antistat will dissolve into the water to form a solution whose surface tension would be lower than the critical surface tension of the polyolefin substrate, and this solution will therefore wet the nonwoven sheet, penetrate the microscopic capillary channels between the individual film-fibril elements, and thereby destroy theliquid water barrier property of the sheet.
• This critical surfactant activity limit appears to be exceeded when the alkyl group of the alkyl phosphate antistat contains six or more carbon atoms.
• some minimum level of surfactant power is required of the antistat simply in order that it may be applied onto the nonwoven sheet (either by immersion, surface coating, spraying, etc.) from aqueous solution.
• the requirement is believed to be that the surface tension of the antistat solution should be such that the solution almost wets the nonwoven sheet.
• the antistat solution should have a surface tension of about 37 i 3 dynes/cm.
• a 0.2 1 percent aqueous solution of potassium amyl phosphate or a l-2 percent solution of potassium butyl phosphate will satisfy this requirement directly.
• Potassium propyl phosphate is not powerful enough a surfactant to meet this surface tension requirement at reasonable concentrations (less than 2 percent) in pure water, but it may successfully be applied to linear polyethylene from a 1 percent solution in a l7-volume percent isopropanol aqueous solvent (surface tension equal 35 dynes/cm.).
• sodium butyl phosphate and ammonium butyl phosphate are both somewhat poorer surfactants than potassium butyl phosphate so that their water solutions at less than 2 percent concentration fail to meet the surface tension requirement; but they too may successfully be applied to linear polyethylene from an alcohol/water solvent.
• potassium butyl phosphate aqueous solutions at concentrations less than 1 percent have surface tensions which are too high (greater than 40 dynes/cm.), but such solutions can be made operable for coating linear polyethylene nonwoven sheets by adding a small quantity (e.g., 0.05 to 0.] percent) of a non-rewettable surface active agent, such as Igepal CO-880 or CO-890 (registered trademark of GAF Corporation's nonionic nonylphenoxy polyoxyethylene ethanol surfactants).
• a non-rewettable surface active agent such as Igepal CO-880 or CO-890 (registered trademark of GAF Corporation's nonionic nonylphenoxy polyoxyethylene ethanol surfactants).
• the antistat finishes of the present invention may comprise a single agent of the formula: M,,R ,,PO (as previously defined) or it may be a mixture of such agents, e.g., potassium butyl phosphate plus potassium isoamyl phosphate. Frequently mixtures are obtained directly in commercial operations.
• M may be chosen to be lithium, sodium, potassium, or ammonium ion but the potassium salts are preferred.
• the agent must contain at least one R group and at least one M group.
• the finishes employed in this invention are not hydrophobic materials like the water repellent coatings conventionally applied to various woven and nonwoven fabrics in order to render them waterproof," but are rather a very restricted group of antistat materials which may be applied to polyolefin film-fibril nonwoven sheets without destroying their inherent hydrophobic liquid water barrier property.
• the result is reported as Log R" with values of 11 (75F. and 50 percent'RH.) being passing and lower values preferred.
• the water barrier performance of the sample is measured by two tests the hydrostatic head test ASTM D-583, paragraph 53A, Method II, results reported in inches" (cms.) with high values preferred; and the rain penetration test ASTM D-583, paragraph 32-37, results reported in grams with lower values preferred.
• EXAMPLE I This example illustrates the effect of varying the size of the alkyl groups of the phosphate antistat agents.
• Samples of nonwoven sheet comprising film-fibril elements of linear polyethylene are prepared by the pro cess of U.S. Pat. No. 3,169,899 at a basis weight of approximately 2.2 oz./yd. (75 gms./m. and subsequently bonded by the process of U.S. Pat. No. 3,442,740. These samples are treated with 0.5 weight percent aqueous solutions of various antistats as indicated in Table I.
• antistats are all mixtures (approximately equimolar) of monopotassium dialkyl and dipotassium monoalkyl phosphate salts with the alkyl group indicated.
• potassium butyl phosphate having the lowest surfactant power, can be successfully applied to the linear polyethylene substrate only by adding a small quantityof a surface tension depressant, in this case Igepal CO-890. This latter material by itself provides essentially no antistat protection for the linear polyethylene substrate.
• EXAMPLE II This example illustrates the effect of changing the quantity of antistat agent applied as a finish to the nonwoven sheet.
• Samples of nonwoven sheet comprising film-fibril elements of linear polyethylene prepared by the process of U.S. Pat. No. 3,169,899 at a basis weight of approximately 1.3 oz./yd. (44.2 gms./m. and subsequently embossed on one side with rows of pointbonds (rib pattern) and surface-embossed on the opposite side with a linen pattern" (as in Examples VI and VII of U.S. Pat. No.
• alkali metal or ammonium alkyl phosphate salts represent an approximately equimolar mixture of a salt con taining one alkyl group with twoalkali metal or ammonium ions and a salt containing two alkyl groups with one alkali metal or ammoniumion.
• EXAMPLE 1111 This example illustrates the effect of various candidate antistat finishes, both within and outside the limitation of the present invention. All candidates are appliedfrorn a solution at the specified concentration, as indicated in Table 111, in a solvent comprising 17 volume percent isopropanol in water such that in each case the surface tension of the solution is low enough to insure good wetting during application to the same linear polyethylene nonwoven substrate employed in Example 11. Note that only the alkali metal and ammonium alkyl phosphates furnish good antistat protection (Runs 3A through 31 versus 3.1 and 3K), that presence of an alkyl group is essential (Run 3L), and that common quaternary alkyl.
• each of the indicated quantity of antistat finish on the treated sheet may be determined either by standard analytical techniques (e.g., phosphorous or potassium analysis, using either chemical or spectroscopic techniques) or simply by calculating the amount of antistat contained in the quantity of treating solution picked up by the nonwoven sheet prior to drying, since the volatility of the antistat salts is very low.
• standard analytical techniques e.g., phosphorous or potassium analysis, using either chemical or spectroscopic techniques
• the antistats are dissolved in water to the indicated weight percent, the sheet samples immersed in the solution and subsequently run through squeeze rolls at the indicated pressures, at which point the percent solution pickup is immediately determined by measuring weight gain, and the sample is then dried.
• the pickup of anti stat, based on the dried sheet is computed from the sowhile permitting passage of water vapor, comprised of film-fibril elements having a surface area greater than 2 meter /gm, said sheet bearing from 0.1 percent to 2 percent by weight of a finish defined by the formula: M,,R ,,PO where M is selected from the group consisting of lithium, sodium, potassium, and ammonium ions, R represents an alkyl group containing 3 to 5 carbon atoms, and n is selected from the integers l and 2.

Landscapes

• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Nonwoven Fabrics (AREA)
• Laminated Bodies (AREA)

Priority Applications (4)

Applications Claiming Priority (1)

Publications (1)

Family

ID=22865260

Family Applications (1)

Country Status (4)

Cited By (19)

Families Citing this family (1)

• 1972
  • 1972-02-29 US US00230448A patent/US3821021A/en not_active Expired - Lifetime
• 1973
  • 1973-02-26 CA CA164,591A patent/CA969816A/en not_active Expired
  • 1973-02-27 GB GB953573A patent/GB1376545A/en not_active Expired
  • 1973-02-28 JP JP2332373A patent/JPS5551068B2/ja not_active Expired

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