Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F1/00—General methods for the manufacture of artificial filaments or the like
  • D01F1/02—Addition of substances to the spinning solution or to the melt
  • D01F1/04—Pigments
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/0007—Electro-spinning
  • D01D5/0015—Electro-spinning characterised by the initial state of the material
  • D01D5/003—Electro-spinning characterised by the initial state of the material the material being a polymer solution or dispersion
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/08—Melt spinning methods
  • D01D5/098—Melt spinning methods with simultaneous stretching
  • D01D5/0985—Melt spinning methods with simultaneous stretching by means of a flowing gas (e.g. melt-blowing)
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F1/00—General methods for the manufacture of artificial filaments or the like
  • D01F1/02—Addition of substances to the spinning solution or to the melt
  • D01F1/10—Other agents for modifying properties
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F1/00—General methods for the manufacture of artificial filaments or the like
  • D01F1/02—Addition of substances to the spinning solution or to the melt
  • D01F1/10—Other agents for modifying properties
  • D01F1/103—Agents inhibiting growth of microorganisms
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/58—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products
  • D01F6/70—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyurethanes

Definitions

• the invention relates to a polyurethane fibre/web, in particular to composite fibres/webs of polyurethane and a particulate, together with uses and processes for manufacture.
• the invention relates to the provision of non-slip products, for instance, but not limited to, for applications in which silicone bands are currently used.
• silicone bands include hosiery (hold-ups for instance), and intimate apparel (for instance brassieres and shapewear), where silicon bands are provided to prevent the garment shifting out of place during wear.
• hold ups are only possible as a product because of the silicone band replacing the suspender belt which would otherwise retain the stocking on the leg.
• Further applications include sportswear (such as swimwear and strap tops) and medical clothing applications (for instance compression garments or supports, such as knee or ankle supports).
• silicone bands can cause allergies in some wearers, can lack flexibility leading to discomfort, and are not easily coloured.
• the lack of breathability and concerns about silicone leaching can deter some consumers from wearing products including silicone bands.
• the invention is intended to overcome or ameliorate at least some aspects of this problem.
• a polyurethane and particulate composite fibre of mean particle diameter in the range 50nm - 50 ⁇ . It has been found that adding particulates (particles) to a polyurethane fibre modifies the friction properties of the fibre, generally resulting in an increase in the frictional coefficient relative to prior art polyurethane fibres and, as a result, in a web which has good non-slip/gripping properties, even where moisture is present, such as water, perspiration or other aqueous solutions so that the skin is wet. Further the webs have excellent shape recovery properties, preventing sagging of the garment in use, and loss of fit over time.
• the particulate modifies the friction co-efficient of the fibre, making it suitable for use in non-slip applications.
• modify is intended to mean that the friction co-efficient of the fibre is modified by at least ⁇ 1.8% relative to the value for any substrate when compared to present commercial polyurethane containing products (i.e. polyurethane without particulate matter).
• the friction coefficient will be increased, for instance by at least ⁇ 1.8%, although often the modification will be far greater, for instance ⁇ 20%, or ⁇ 50% or even ⁇ 100%; often the modification will be an increase.
• the particulate may be any particulate which modifies the friction coefficient of the fibre, typically to increase this.
• an antimicrobial particle and so the particle may be selected from a metal, such as silver, copper, gold, titanium, zinc, iron, aluminium or combinations thereof. Silver will often be used to enhance the antimicrobial properties of the fibre.
• pigment particulates may be used, as these can colour the fibre in addition to modifying the friction properties thereof.
• inorganic compounds such as silica (such as Celite), calcium phosphate (such as ivory black), ceramic or glass microparticles may be used as these are inexpensive, safe on the skin, nontoxic and have been shown to give high friction values.
• Polymeric particles may also be added, for instance polyethylene or cellulose acetate particles for the same reasons.
• the use of silver particles in the size range 5 - 10 ⁇ has been found to offer particularly high static friction coefficients, as has silver in the range 0.5 - 1 ⁇ , this latter particle size being especially effective when used at low levels, such as in the range 1 - 3 wt% or around 2 wt%.
• the fibre will comprise in the range 1 - 25 wt% particulate, often in the range 2 - 10 wt%. At these ranges the particulate has been found to increase the friction coefficient of the fibre and resulting web, without, it is believed, reducing overall fibre strength significantly.
• the range 2 - 10 wt% particles has been found to be particularly effective at providing a web which had good non-slip properties.
• the particulate comprises particles of mean particle size in the range 50nm - 50 ⁇ , often in the range 0.5 - 25 ⁇ , in the range 0.5 - 10 ⁇ or in the range 0.7 - 1.5 ⁇ .
• Particle size is important as it is believed that this offers one of the advantages over known technologies, in that particle sizes in this range offer a web with a very fine surface topography, such that the particles can settle in the grooves of the skin, providing intimate contact, without loss of comfort.
• This micro-scale contact is much more effective at preventing slipping of the web across the skin than the macro-scale friction based contact provided by silicone band technologies.
• the particles will be in the micro- or sub-micro scale rather than the nano-scale to ensure that toxicity is avoided.
• the term "diameter” is intended to refer to the width of the fibre or particle across the largest part of its cross-section.
• the fibre will be of mean diameter in the range 0.05 - 20 ⁇ , often in the range 0.2 - 15 ⁇ , or 1.5 - 5 ⁇ .
• the diameter of the fibre can be controlled through careful selection of the manufacturing method, for instance, melt blowing processes generally produce fibres of larger diameter than electrospinning techniques. Fibres of the diameters described above have been found to offer increased contact with the skin, because of the large surface area relative to fibres of larger diameters.
• fibres with diameters in this range also allows for more particulate to be present at the surface of the fibre, improving the friction properties of the fibre relative to fibres of larger diameters.
• An advantage of these techniques is that they inherently produce fibres with a range of diameters. This allows them to interact more effectively with the skin, as the range of fibre diameters is well suited to interacting with the range of groove sizes found in the skin.
• a ratio of particle size to mean fibre diameter is in the range 0.05: 1 - 2:5 This is desirable because at such ratios the friction with the skin is excellent.
• a web comprising a plurality of fibres according to the first aspect of the invention.
• a web according to the second aspect of the invention may be for non-slip applications, applications where fabric breathability is important and/or antimicrobial applications among others.
• the web may be used in hosiery (hold-ups for instance), and intimate apparel (for instance brassieres and shapewear).
• Further applications include sportswear (such as swimwear and strap tops) and medical clothing applications (for instance compression garments or supports, such as knee or ankle supports).
• sportswear such as swimwear and strap tops
• medical clothing applications for instance compression garments or supports, such as knee or ankle supports.
• a particular advantage of the invention is that the fibres offer their friction modification properties regardless of whether the substrate, for instance skin, is wet or dry. This makes them particularly suitable for use in swimwear and sportswear applications.
• a method of making a fibre according to the first aspect of the invention comprising forming the polyurethane and particulate composite fibre using a technique selected from but not limited to electrospinning or melt blowing. Often electrospinning will be used, such that the webs produced will be electrospun. Electrospinning offers the advantage that the fibre diameters are smaller than other methods, including melt-blowing. It is often the case that the fibre is sufficiently thin to interact with the grooves of the skin, working with the particulate to modify the friction co-efficient of the web. Often the method will comprise:
• concentrations of polyurethane have been found to provide the optimal balance between fibre diameter and consistency of fibre diameter. Higher concentrations of polyurethane in the solution may produce fibres of undesirably thick diameter, reducing the surface area, surface availability of the particles and weakening the strength of the fibre matrix. Lower concentrations of polyurethane can lead to webs with uncontrolled fibre diameters along fibre lengths reducing the uniformity of the web. Where melt-blowing is used, the method will often comprise:
• the particulate comprises 1 - 25 wt% of the fibre, and may be a particle selected from a pigment particulate, an inorganic compound (optionally selected from silica, calcium phosphate, ceramic or glass microparticles), a metal (optionally selected from silver, copper, gold, titanium, zinc, iron, aluminium or combinations thereof), a polymer or combinations thereof.
• the particulate comprises particles of mean particle size in the range 50nm - 50 ⁇ .
• the particulate comprises particles of multimodal, in some cases, bimodal particle size distribution.
• the fibre will be of mean diameter in the range 0.2 - 20 ⁇ , and a ratio of particle size to mean fibre diameter is in the range 0.05: 1-2:5.
• Figure 1 is an SEM image of an electrospun polyurethane web (4480x magnification, mean fibre diameter 1.8 ⁇ );
• Figure 2 is an SEM image of an electrospun polyurethane web similar to that of Figure 1, but with the incorporation of silver particles to form a hybrid fibre (4970x magnification, mean fibre diameter 1.8 ⁇ , particle size range 0.5 - ⁇ );
• Figure 3 is a graph illustrating the static friction of a range of web compositions when tested against a plain cotton sample
• Figure 4 is a graph illustrating the static friction of a range of web compositions when tested against a cotton muslin sample
• Figures 5a, 5b and 5c are graphs illustrating the static friction of a range of web compositions when tested against dry pig skin;
• Figure 6a is a graph illustrating the static friction of a range of web compositions when tested against wet pig skin
• Figure 6b is a graph comparing the static friction of a range of web compositions when tested with dry and with wet pig skin (left hand graph is dry, right hand graph is wet);
• Figure 7 is a graph illustrating the static friction of web compositions comprising silver particles in selected size ranges against a pig skin sample
• Figure 8 shows the results of antimicrobial testing for an electrospun membrane, 10% polyurethane with 10%> (0.5-1 ⁇ ) silver particles membrane tested against [A] S. aureus and [B] E. coli;
• Figure 9 is a schematic showing the dimensional stability template pattern in a wash fastness test.
• Figures 10a - lOd are graphs showing the colour fastness results of polyurethane webs with a) 10%> red pigment, b) 10%> violet pigment, c) 10%> blue pigment and d) 10%> blue pigment with Celite.
• Polyurethane (SelectophoreTM, at the desired wt%) was dissolved in DMF:THF (15 ml, 60:40 (v:v)) with stirring over 24 hours.
• the particulate was added as defined in Table 1 below, slowly with stirring and allowed to disperse over the period of an hour.
• a 10 wt% solution of SelectophoreTM polyurethane was prepared using a 60:40 DMF:THF solvent ratio.
• SelectophoreTM polyurethane (1.5 g) was added to 15 ml of the solvent mixture with stirring and left to dissolve overnight.
• Once dissolved particle/pigment additive was then added to the solution with continuous stirring for 10 minutes (according to Table 1), the solution was then added to the 10 ml syringe and electrospun for approximately 4 hours.
• the aluminium foil collection plate was periodically rotated 90 degrees resulting in more uniform fibre coverage.
• the syringe and needles were wiped clean using tissue and then washed using acetone, followed by distilled water.
• Friction Test The friction coefficient was determined in accordance with European Standard EN ISO 8295:2004. Applied force (F p ) of 1.96N via an 80g sled, and a 120g weight for a total weight of 200g. The speed was 100 mm/min. Sample size was 90 x 755mm.
• the coefficient of static friction can be defined by the equation:
• F p 1.96N (the normal force which comes from 200 g of weight applied to the top of the sample).
• F s represents the static friction force (N) measured by the machine and is always proportional to the static friction coefficient.
• the static friction force arises from the interlocking of surface irregularities between the polyurethane sample and the test surface. As a force is applied horizontally to the test sample this interlocking force will increase to prevent any relative movement of the sled. This force increases until a threshold force is reached where motion of the sled begins. It is this threshold point of motion which defines the static force.
• Webs The tested webs were electrospun polyurethane with added particulates.
• Antimicrobial Tests were followed AATCC 100. 3mm diameter samples of the web were tested against E. Coli, (MacConkey agar plates) and S. Aureus (blood agar plates) by 24 hour incubation at 37°C. The plates were inoculated with 30 ⁇ 1 of 0.5 McFarland standard E. coli or S. aureus diluted in 3ml of PBS or saline solution. Anaerobic testing used the above methods, however C. difficile was the model bacteria selected (CCEYL plates) and the incubation period was 48 hours at 37°C in an anaerobic incubator. All tests were repeated three times.
• Scanning Electron Microscopy The structure and morphology of the electrospun fibre mats produced were examined by scanning electron microscopy (SEM; Carl Zeiss EVO) at the Leeds Electron Microscopy and Spectroscopy (LEMAS) centre. SEM images were taken at different magnifications for all electrospun fibres for comparison.
• Fibre Analysis Media Cybernetics Image Pro Analyser Plus was used to analyse images captured via SEM. The software was used to measure fibre diameters of samples; a minimum of 75 fibre diameters were recorded for each sample and digitised in order to obtain values for the mean, maximum and minimum fibre diameters for each sample.
• R is the reflectance value at a specific wavelength
• K absorbance coefficient
• S is the scattering coefficient
• Breathability tests were carried out following the BS 7209: 1990 standard for 20 hours in a climate controlled laboratory (temperature 20 ⁇ 2 °C and relative humidity 65 ⁇ 5 %). Test samples were placed over a weighed amount of distilled water and the water allowed to evaporate slowly (through the fabric) prior to reweighing after a set time. This calculation of water loss can be applied to the following equation which allows the relative breathability of the fabric to be assessed.
• WVP is the water vapour permeability (g/m 2 /day)
• Am is the change in mass of water in grams
• A is the area of the test material in m 2
• t equals the time in hours for the experiment.
• the WVP index is a breathability ratio which compares the test samples to the reference fabric.
• the friction test was also applied to a cotton gauze (CX202 cotton gauze L/State 96cm, CC28).
• the gauze is a lighter weight muslin style fabric in which the fibre surfaces are sized so that they are smoother. It would be expected that a lower friction be observed in these tests.
• Table 3 and Figure 4 The results are shown in Table 3 and Figure 4.
• inventive samples have good friction properties indicating utility in non-slip apparel applications.
• Porcine (pig) skin models are a useful tool to predict human interactions with compounds because both human and porcine skin have a spare hair coat, a thick well differentiated epidermis, a dermis that has a well-differentiated papillary body and a large content of elastic tissue, alongside similar size, distribution and communication of the dermal blood vessels.
• porcine skin differ in the type of sweat glands present in majority (apocrine vs. eccrine).
• wt% silver particles of size range 4.49 2.29
• the static friction observed is significantly higher than the minimum values for skin adherence, for instance 10% silver at 5 - 8 ⁇ provides an excellent static friction coefficient.
• the Figure 5c clearly shows that the fibres of the invention outperform both conventional silicone systems and (specifically a woven elastane, Nylon and polyurethane system in which the polyurethane is present in the warp only), polyurethane systems. This series of tests also showed that pigment particles can successfully form composite fibres, and that the pigment particles are sufficient, when used alone with polyurethane, to increase the friction properties of the web.
• Figure 6a and the table above shows that the samples in this test performed well, compared to the silicone product of the prior art ("silicone") indicating that this material can provide higher friction in wet conditions.
• the main contributing factor to the good frictional resistance in wet conditions is believed to be the porous nature of the electrospun material.
• the water present on the skin surface is able to leach into the membrane (between the fibres) effectively removing some surface water and allowing the membrane to interact with the skin surface.
• Figure 6b shows that for the same pig skin sample, that performance in the wet is superior to that in the dry.
• the static friction values between all these samples are less variable than the dry tests. This supports the argument that it is the porosity of the material and not the added particles that leads predominantly to the high friction values in wet conditions.
• Table 8 The results are shown in Table 8 below:
• the web has an antimicrobial effect on contact with the bacteria. There is no zone of inhibition around the web, indicating that there is no leaching of the particles from the web.
• Electrospun fibrous polyurethane webs can be produced whilst simultaneously incorporating colour into the product in a single step, which provides a significant economic advantage in production relative to known multi-step methods.
• Table 11 shows the results of the WVP testing:
• the samples are at least as breathable, and generally more so, than the polyester reference sample.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Dispersion Chemistry (AREA)
• Artificial Filaments (AREA)
• Nonwoven Fabrics (AREA)
• Chemical Or Physical Treatment Of Fibers (AREA)

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• 2015
  • 2015-10-08 GB GBGB1517791.8A patent/GB201517791D0/en not_active Ceased
• 2016
  • 2016-10-06 EP EP16781175.1A patent/EP3359713B1/en active Active
  • 2016-10-06 US US15/766,255 patent/US20180291529A1/en not_active Abandoned
  • 2016-10-06 JP JP2018517747A patent/JP7046369B2/ja active Active
  • 2016-10-06 DK DK16781175.1T patent/DK3359713T3/da active
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