Classifications

• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/0005—Other compounding ingredients characterised by their effect
  • C11D3/0094—High foaming compositions
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
  • A47L13/00—Implements for cleaning floors, carpets, furniture, walls, or wall coverings
  • A47L13/10—Scrubbing; Scouring; Cleaning; Polishing
  • A47L13/16—Cloths; Pads; Sponges
  • A47L13/17—Cloths; Pads; Sponges containing cleaning agents
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D17/00—Detergent materials or soaps characterised by their shape or physical properties
  • C11D17/04—Detergent materials or soaps characterised by their shape or physical properties combined with or containing other objects
  • C11D17/049—Cleaning or scouring pads; Wipes

Definitions

• the invention relates to a wiping article suitable for use in cleaning soiled surfaces in the presence of water.
• the wiping article can be adapted for cleaning hard surfaces, particularly those to be found in the domestic kitchen and bathroom, or for cleaning the surface of the human body, for instance when taking a shower.
• a problem which can arise with both the above-­mentioned categories of wiping article is that when used in the presence of a substantial quantity of water the soap or detergent active with which they are impregnated is leached out too quickly, leaving the article prematurely exhausted of soap or detergent active. This might for instance be manifested as a hard surface wipe being exhausted after a single use, or a wipe intended for use under the shower failing to complete a single use.
• EP 161911 proposed to delay release of impregnating detergent active compound by means of moisture barrier areas, applied in a pattern to sandwich the detergent active applied in a similar pattern and retarding the leaching of the detergent active from the wipe.
• a substantially dry-to-the-touch wiping article which is suitable for use in cleaning soiled surfaces in the presence of water, the article comprising first and second substrate layers with surfactant in solid form sandwiched between them, characterised in that the surfactant
• a liquid crystal phase when the surfactant comes into contact with water, especially formation of a cubic or hexagonal, most preferably hexagonal, liquid crystal phase.
• Such liquid crystal phase(s) will form at appropriate points in the concentration gradient between surfactant in the wiping article, and water permeating into the article.
• Formation of a hexagonal liquid crystal phase when water contacts the solid surfactant is particularly effective in delaying release of surfactant from the wiping article because the liquid crystal phase is highly viscous and is itself slow to dissolve in water, moreover it forms a temporary shield between the remaining solid surfactant and any water.
• Formation of a liquid crystal phase will serve to retard dissolution when the wiping article is contacted by water at any temperature at which the liquid crystal phase exists. Desirably this is from 20°C or the surfactant's Krafft temperature (whichever is greater) upwards to at least 30°C preferably 35 or 40°C and still better up to 50°C which is approximately the highest temperature which hands can bear.
• the surfactant will display a Krafft temperature below 20°C with liquid crystal phase existing over a range of temperatures extending at least from 20°C to 30°C, or the surfactant will display a Krafft temperature above 20°C with liquid crystal phase existing over a range of temperatures extending upwards from the Krafft temperature and reaching a temperature which is at least 30°C.
• the surfactant should foam in water, because this provides the user with visual confirmation of the presence of surfactant.
• a fairly high critical micelle concentration would be desirable in order that the surfactant should foam. It is preferred that the critical micelle concentration should be at least 2mMole/litre, better at least 4 or 5mMole/litre.
• the surfactant needs to be in the form of a solid, so that it remains in place within the wiping article, when the article is dry.
• the surfactant itself can exist as a solid at 20°C, preferably at temperature up to at least 25°C. This makes it possible to incorporate solid concentrated surfactant between the two layers of substrate, and have the surfactant stay in place during storage of the dry wiping article before use.
• the solid surfactant should not be sticky, more preferable is that the surfactant is able to exist as dry particles at 20°C, preferably at temperatures of at least 25°C.
• the surfactant may well be used in particulate form, with the particles trapped between the two substrate layers.
• the rate of dissolution may be adjusted to some extent by choice of the size of the surfactant particles.
• the surfactant may be a non-soap detergent.
• Several types can be used.
• One possible type of surfactant is C14 to C16 sulphobetaines. These readily form hexagonal liquid crystal phases on contact with water. When dry they are crystalline solids.
• Preferred surfactants for this invention are mild to the skin, e.g. monoalkyl sulphosuccinates or fatty acyl isethionates where the alkyl or acyl group has from 8 to 22 carbon atoms, preferably 10 to 16 carbon atoms.
• This anionic surfactant must have a solubilising cation, and alkali metal ions are preferred.
• these types of surfactant frequently contain fatty acids and other impurities, but this does not reduce their usefulness in the present application.
• sodium cocoyl isethionate which has a Krafft temperature of 26°C. Above the Krafft temperature both hexagonal and lamella liquid crystal phases form in the concentration gradient between the surfactant and water. When this surfactant is used, at temperatures below the Krafft temperature, there is restricted solubility in water and hence slow rate of dissolution. Above the Krafft temperature the hexagonal liquid crystal phases retards solution. The hexagonal liquid crystal phase exists from the Krafft temperature up to well over 50°C.
• the invention requires substrate layers. It is substrate layers which provide the wiping surfaces, and which give the article its strength and integrity.
• the material of at least one substrate layer must be water permeable.
• the substrate layers are sheets of fibrous material.
• a non-woven fibrous sheet is particularly preferred.
• Cellulose fibres are particularly suitable in view of their ability rapidly to absorb water when employed to clean a soiled surface.
• the substrate layers can also comprise other fibrous materials such as polyamide, polyester and polypropylene, or mixtures of such fibres, which are particularly useful in providing the article with extra wet strength.
• the wet strength of substrate layer material can also be increased by incorporation of suitable binders such as styrene butadiene lattices, or an acrylic binder, or polyvinyl acetate, or polymer emulsions.
• suitable binders such as styrene butadiene lattices, or an acrylic binder, or polyvinyl acetate, or polymer emulsions.
• the absorbent substrate can be made from paper, in which case it will generally comprise cellulose fibres which are relatively short in length. Additives, such as hydroxyethyl cellulose may be employed to provide added wet strength.
• the substrate layers may be the same or may be different. It can be advantageous to employ different substrate layers, for example choosing one substrate material to provide good wet strength and another substrate material to provide good absorbency.
• One preferred substrate material is a non-woven comprising cellulose fibres an example of which is Mitsubishi TCF 408, a 100% cuprammonium rayon spun bonded non-woven having the following technical specifications: Nominal basis weight (g/m2) 82.5 Thickness ( ⁇ m) 500 Dry tensile strength: machine direction (N/m) 635 Dry tensile strength: cross direction (N/m) 565 Wet tensile strength: machine direction 498 Wet tensile strength: cross direction (N/m) 447 Absorption capacity (g/g) 5
• Another substrate material is a non-woven comprising cellulose fibres such as Storalene 715:50 or Storalene 717:50 available from Stora-Kopparberg, Sweden, which contains the following ingredients: % per w/w Cellulose fibres (wood pulp) 33 Cotton linters 29 Rayon 17 Polyamide 4 Binder* 17 *Storalene 715:50 contains an acrylic binder and Storalene 717:50 contains a polyvinyl acetate binder.
• Storalene 715:50 or Storalene 717:50 available from Stora-Kopparberg, Sweden, which contains the following ingredients: % per w/w Cellulose fibres (wood pulp) 33 Cotton linters 29 Rayon 17 Polyamide 4 Binder* 17 *Storalene 715:50 contains an acrylic binder and Storalene 717:50 contains a polyvinyl acetate binder.
• Storalene 715:50 and Storalene 717;50 are set out below: Storalene 715:50 717:50 Nominal basis weight (g/m2) 50 50 Thickness ( ⁇ m) 400 365 Dry tensile strength-machine direction (N/m) 600 625 Dry tensile strength-cross direction (N/m) 450 330 Wet tensile strength-machine direction (N/m) 300 205 Wet tensile strength-cross direction (N/m) 250 95 Absorption capacity (g/g) 4 4 4
• a further example of a suitable substrate material is Hi-Loft 3051 available from Scott Paper Co, a random wet-­laid lofty paper web having a base weight of 82 g/m2 and a porosity of 92%. This is bulky high-porosity sheet material having a high wicking rate.
• a substrate layer it is possible for a substrate layer to consist of a laminate of more than one layer, for example a laminate of an absorbent material with a reinforcing material at the exterior surface. It is possible for abrasive particles to be applied to the exterior surface of one or both substrate layers. Suitable abrasive particles are polyvinyl chloride granules. The application of abrasive granules to the exterior surface of a wiping article is described in our published European application EP 211664.
• Abrasive material may be applied to the exteriors of both substrate layers, and possibly different abrasive materials could be employed so that one substrate layer provided a harsher abrasive surface than the other. Preferable however is to have abrasive on one substrate layer and a smooth surface on the other substrate layer making it suitable for polishing off after initial cleaning with the abrasive side of the wiping article.
• Joining two substrate layers with surfactant sandwiched between them may be accomplished in various ways. It may be carried out by heat sealing the two layers to each other with a regular pattern or array of heat sealing, as described for instance in EP 66463 and EP 112654. Alternatively the substrate layers may be joined by use of sintered polyethylene in the manner described in our copending application [case C3263] filed simultaneously with this application and claiming priority from British application 8817727.4.
• wiping articles were prepared by a standard procedure, in which particles of surfactant were sandwiched between substrate layers.
• One substrate layer consisted of Mitsubishi TCF 408 mentioned above and the other consisted of Hi-Loft 3051 also mentioned above.
• To manufacture the wiping article squares of each substrate material, 30cm along each side were employed. 2.5g polyethylene beads of maximum size 0.3mm were sprinkled over one surface of each square of substrate and the substrate then heated in an oven to melt the beads sufficiently to bond to the substrate layer.
• a portion of powdered surfactant was then sprinkled over a 27.5cm x 27.5cm portion of the polyethylene-coated surface of one substrate layer, the other substrate layer was then superimposed so that the polyethylene-coated surfaces were confronting each other and sandwiching the surfactant. Then the assembly was passed between heated rollers to effect heat-sealing between the polyethylene layers. The resulting laminate was then trimmed to a square of 28cm along each side.
• wiping articles were prepared using several surfactant materials and several dosages of each surfactant material.
• the surfactants employed in these Examples were: sodium dodecyl sulphate whose Krafft temperature and critical micelle concentration are reported as 16°C and 8mMoles/litre in Surfactants and Interfacial Phenomena, Milton Rosen, Wiley 1978 (other literature reports lower Krafft temperatures); sodium dodecyl sulphonate for which the same reference quotes a Krafft temperature of 38°C and a critical micelle concentration of approximately 10mMole/litre; sodium di C6-C8 alkylsulphosuccinate having a Krafft temperature of 15-18° C; sodium cocoyl isethionate (Elfan AT 84G from Akzo Chemie) whose manufacturers state that it has a Krafft temperature of 26°C.
• Wiping articles prepared as above, using various surfactants were tested by a procedure to determine the number of times they could be wet and squeezed out before becoming exhausted of surfactant. This test was carried out as follows. 25g of water (tap water of approximately 10° French hardness at a temperature of 35-40°C) was poured on to a wiping article which was then squeezed, thereby squeezing out approximately half the water from the article. The water squeezed out was poured into a 100ml measuring cylinder and shaken for 5 seconds. Any surfactant dissolved from the wiping article would cause foaming. A foam volume greater than the volume of liquid in the measuring cylinder after standing for two minutes was regarded as adequate foaming. The procedure was repeated until the observed foaming ceased to be adequate.
• the particle size of the isethionate also had an effect: larger particles dissolving more slowly. With the largest particles of isethionate the rate of dissolution was so slow that 0.2g surfactant did not give adequate foaming at all. Even the higher loadings of the larger sizes gave poor foam on the first cycle of wetting and squeezing out.
• isethionate For a preferred wiping article isethionate was used, applying 0.1g of particles smaller than 0.35mm and 0.4-0.9g of particles in the 0.5 to 1.0mm size range.
• the wiping articles appeared to be producing more foam than desired, and felt slimy, except when the amount of surfactant included in the wiping article was at the low (0.2g) level. This was also observed with the wiping articles having dialkylsulphosuccinate as surfactant. When sodium cocoyl isethionate was used as surfactant this over foaming and apparent slimy feel were less apparent than with the other two surfactants.
• the release of surfactant from the articles was tested by the following procedure. 25g of water (approximately 10° French hardness) at a temperature of 25°C was poured on to a wiping article. The article was squeezed, thereby squeezing out approximately half the water from the article. This water was collected. The cycle of wetting the article, squeezing and collecting the expressed water was carried out repeatedly. The concentration of surfactant in samples of the expressed water was determined by titration with hyamine, which is a cationic surfactant. The extent of foaming was also noted. Results are set out in the following Table.
• Wiping articles were made by the above general procedure.
• the surfactant employed was sodium cocoyl isethionate having a particle size in the range from 0.5 to 1mm.
• the release of surfactant was determined by the procedure of Example 2. This test was carried out twice, once using water at 25°C and once using water at 35°C. The results are set out in the following table.
• Wiping articles were prepared using sodium cocoyl isethionate of various particle sizes as used in Example 1.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Cleaning Implements For Floors, Carpets, Furniture, Walls, And The Like (AREA)
• Detergent Compositions (AREA)
• Laminated Bodies (AREA)

Applications Claiming Priority (2)

Publications (3)

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Family Applications (1)

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Cited By (21)

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Citations (4)

Family Cites Families (5)

• 1988
  • 1988-07-26 GB GB888817728A patent/GB8817728D0/en active Pending
• 1989
  • 1989-07-24 AU AU38885/89A patent/AU618383B2/en not_active Ceased
  • 1989-07-25 ES ES89307524T patent/ES2045443T3/es not_active Expired - Lifetime
  • 1989-07-25 BR BR898903682A patent/BR8903682A/pt not_active IP Right Cessation
  • 1989-07-25 DE DE89307524T patent/DE68909140T2/de not_active Expired - Fee Related
  • 1989-07-25 EP EP89307524A patent/EP0353013B1/de not_active Expired - Lifetime
  • 1989-07-26 JP JP1193781A patent/JPH0822269B2/ja not_active Expired - Lifetime
  • 1989-07-26 ZA ZA895684A patent/ZA895684B/xx unknown

Patent Citations (4)

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