U.S. patent application number 10/402834 was filed with the patent office on 2003-09-18 for disposable, moisture vapour permeable, liquid impermeable covering sheet having odour reduction properties.
This patent application is currently assigned to The Procter & Gamble Company. Invention is credited to Bonfanti, Lidia, Pesce, Antonella, Porter, Philip, Russo, Elisabetta, Sirianni, Giuseppe, Trujillo, Rafael.
Application Number | 20030172458 10/402834 |
Document ID | / |
Family ID | 28043206 |
Filed Date | 2003-09-18 |
United States Patent
Application |
20030172458 |
Kind Code |
A1 |
Bonfanti, Lidia ; et
al. |
September 18, 2003 |
Disposable, moisture vapour permeable, liquid impermeable covering
sheet having odour reduction properties
Abstract
The present invention relates to a disposable covering sheet
which is moisture vapour permeable and liquid impermeable and has
odour control properties and, if desired, also active agent
releasing properties. The disposable covering sheet comprises at
least a moisture vapour permeable layer and a liquid impermeable
but moisture vapour permeable film layer of thermoplastic
compositions. The disposable covering sheet such as, for example, a
mattress cover or a pillow cover gives a better comfort to the user
by providing odour control properties and, if desired, also active
agent releasing properties. The disposable covering sheet of the
present invention can find a variety of applications wherein
moisture vapour permeability and liquid imperviousness combined
with specific odour control properties and preferably also active
agent releasing properties are desirable.
Inventors: |
Bonfanti, Lidia; (Sambuceto
di S. Giovanni Teatino, IT) ; Pesce, Antonella;
(Pescara, IT) ; Porter, Philip; (Brussels, BE)
; Russo, Elisabetta; (Rome, IT) ; Sirianni,
Giuseppe; (Rome, IT) ; Trujillo, Rafael;
(Waterloo, BE) |
Correspondence
Address: |
THE PROCTER & GAMBLE COMPANY
INTELLECTUAL PROPERTY DIVISION
WINTON HILL TECHNICAL CENTER - BOX 161
6110 CENTER HILL AVENUE
CINCINNATI
OH
45224
US
|
Assignee: |
The Procter & Gamble
Company
Cincinnati
OH
|
Family ID: |
28043206 |
Appl. No.: |
10/402834 |
Filed: |
March 28, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10402834 |
Mar 28, 2003 |
|
|
|
PCT/US01/42388 |
Oct 1, 2001 |
|
|
|
Current U.S.
Class: |
5/490 ; 5/696;
5/699; 5/939 |
Current CPC
Class: |
A47G 9/007 20130101 |
Class at
Publication: |
5/490 ; 5/699;
5/939; 5/696 |
International
Class: |
A47G 009/04 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 2, 2000 |
EP |
00121590.4 |
Claims
What is claimed is:
1. A disposable, moisture vapour permeable, liquid impermeable,
covering sheet comprising at least a moisture vapour permeable
layer and a liquid impermeable but moisture vapour permeable film
layer of thermoplastic composition applied onto said moisture
vapour permeable layer characterised in that said covering sheet
comprises odour control means which are able to provide a malodour
reduction of at least 15%, as measured according to the Odour
Control Test described herein.
2. A disposable, moisture vapour permeable, liquid impermeable
covering sheet according to claim 1 wherein said odour control
means comprises cyclodextrin and/or zeolite.
3. A disposable, moisture vapour permeable, liquid impermeable,
covering sheet according to claim 1 further characterised in that
said covering sheet comprises an active agent releasing system.
4. A disposable, moisture vapour permeable, liquid impermeable,
covering sheet according to claim 3 characterised in that said
active agent releasing system is able to provide a long lasting
release of active agents.
5. A disposable, moisture vapour permeable, liquid impermeable
covering sheet according to claim 3 wherein said active agent is a
perfume.
6. A disposable, moisture vapour permeable, liquid impermeable
covering sheet according to claim 3 wherein said active agent is a
perfume and said odour control means is a zeolite.
7. A disposable, moisture vapour permeable, liquid impermeable
covering sheet according to claim 5 wherein said perfume is a
starch encapsulated perfume.
8. A disposable, moisture vapour permeable, liquid impermeable
covering sheet according to claim 6 wherein said perfume is a
starch encapsulated perfume.
9. A disposable, moisture vapour permeable, liquid impermeable,
covering sheet according to claim 1 characterised in that its Water
Vapour Transmission Rate (WVTR) is at least 400
g/m.sup.2.multidot.24 h.
10. A disposable, moisture vapour permeable, liquid impermeable,
covering sheet according to claim 9 characterised in that said
Water Vapour Transmission Rate (WVTR) is at least 500
g/m.sup.2.multidot.24 h.
11. A disposable, moisture vapour permeable, liquid impermeable,
covering sheet according to claim 9 characterised in that said
Water Vapour Transmission Rate (WVTR) is at least 600
g/m.sup.2.multidot.24 h.
12. A disposable, moisture vapour permeable, liquid impermeable,
covering sheet according to claim 1 wherein said covering sheet is
a disposable covering sheet for bedding articles.
13. A disposable covering sheet for bedding articles according to
claim 12 wherein said covering sheet is a disposable mattress cover
or a disposable pillow cover.
14. A disposable mattress cover according to claim 13 characterised
in that said mattress cover has at least four adhesive means for
fixing it to the longitudinal sides of a bed mattress.
Description
CROSS REFERENCE TO PRIOR APPLICATION
[0001] This is a continuation of International Application
PCT/US01/42388, with an international filing date of Oct. 1, 2001,
and published in English.
FIELD OF THE INVENTION
[0002] The present invention relates to a disposable covering sheet
preferably for bedding items such as mattresses, pillows, etc.
which is moisture vapour permeable, liquid impermeable, and has
odour reduction properties. The covering sheet comprises liquid
impermeable formed structures having a moisture vapour permeability
comprising thermoplastic compositions preferably applied onto a
moisture vapour permeable substrate. The covering sheet of the
present invention can find a variety of applications wherein
moisture vapour permeability, liquid imperviousness, disposability,
comfort, specific odour control properties and, if desired, also
active agents releasing properties are desirable. Preferably the
covering sheet of the instant invention is a mattress cover or a
pillow cover.
BACKGROUND OF THE INVENTION
[0003] Covering sheets, particular covering sheets for bedding
articles, such as bed mattress covers, are known in the art. A
primary use of these articles is to protect mattresses,
particularly bed mattresses, but also pillows, cushions, duvets,
upholstery, from contaminants, e.g. from dust, liquids, or bodily
fluids, for example in environments where a mattress is intended to
be used by different users, such as in hospitals, hotels, or rental
houses. Furthermore, mattress covers are used in house for
providing a mattress with a protective covering.
[0004] More recently mattress covers have been also proposed to act
as an allergen barrier to control house mites that live in the
dust, typically on and within mattresses where they can find
favourable environmental conditions in terms of temperature and
nourishment.
[0005] It has long been established that house mites, also known as
dust mites, are a source of house dust allergens that not only
cause allergies, but also adversely contribute to other
pathologies, such as asthma. It has also been established that use
of allergen control measures is effective in controlling these
conditions. Allergen-proof encasing to contain mites to prevent
allergen egress has long been used in mattresses, such as bed
mattresses, pillows, cushions, duvets, upholstery.
[0006] Mattress covers come in direct or indirect (i.e. through
further intermediate layers, e.g. bed sheets, or pillowcases)
contact with the human body, therefore it is important that such
covers are moisture vapour permeable for comfort reasons, in
addition to being liquid impermeable in order to provide the
mattress with the desired protection against external agents. When
used as a barrier against dust mites they should also have an
allergen barrier capability.
[0007] Various examples of disposable mattress covers which are at
the same time liquid impermeable and breathable, i.e. moisture
vapour permeable, are known in the art.
[0008] Known disposable mattress covers comprise different
materials or structures which are capable of providing a liquid
barrier, in addition to providing moisture vapour permeability,
preferably air permeability. Such structures or materials can
comprise a single layer, or multiple layers laminated together. An
example are structures comprising thermoplastic microporous films,
e.g. laminated to fibrous layers such as nonwoven layers.
[0009] Particularly preferred materials which are suitable for
disposable mattress covers are hydrophilic continuous films, also
known as "monolithic films", that do not allow the flow of moisture
vapour through open pores or apertures in the material, but do
transfer substantial amounts of moisture vapour through the film by
absorbing water on one side of the film where the moisture vapour
concentration is higher, and desorbing or evaporating it on the
opposite side of the film where the moisture vapour concentration
is lower.
[0010] In our patent applications EP 0963760 and EP 0964026
thermoplastic compositions are disclosed for making hydrophilic
continuous moisture vapour permeable, liquid impermeable layers
having preferred characteristics of moisture vapour permeability
and liquid imperviousness. The disclosed preferred thermoplastic
compositions are also readily processable so as to provide a
coating having the desired thickness onto a substrate, so avoiding
the need of complex traditional extrusion apparatuses. This is
achieved by modifying the viscosity of the thermoplastic polymers
by means of the inclusion in the composition of a suitable
plasticiser or blend of plasticisers that lowers such viscosity.
This allows to utilise with these preferred compositions typical
process conditions known in the art for the direct coating of low
viscosity hot melt compositions onto a substrate in order to form a
moisture vapour permeable, liquid impervious film or layer.
[0011] Disposable, moisture vapour permeable, liquid impermeable
mattress covers comprising a moisture vapour permeable, liquid
impermeable structure, which in turn comprises a layer of the
thermoplastic compositions according to either EP 0963760 or EP
0964026, preferably applied onto a moisture vapour permeable
substrate, e.g. a fibrous layer such as a nonwoven layer in order
to form a composite structure, are particularly preferred since
they provide better moisture vapour permeability combined with
liquid imperviousness, and also take advantage of the increased
ease of manufacture associated to the above mentioned
compositions.
[0012] Another improvement to disposable mattress covers is
described in our European patent application No. 99124535.8, filed
on Dec. 9, 1999, where an increased friction is established between
the disposable mattress cover and the mattress surface during the
use, when i.e. the mattress cover is typically subjected to a
certain compression against the mattress itself, in order to
minimise possible misplacements of the cover during its use, for
example when the mattress is a bed mattress or a pillow, and the
mattress cover can be moved or misplaced by the user's movement,
e.g. during the sleep. This is particularly important when the
mattress cover is intended for partial covering of the external
surface of a mattress, for example of the upper surface of a bed
mattress, e.g., in combination with traditional means for
connecting the cover to the mattress, such as for example elastic
bands or strands applied at the corners of a rectangular bed
mattress cover.
[0013] Provision of an increased friction between the mattress
cover and the mattress is however also useful in the context of a
mattress cover intended for total encasing of a mattress. In both
cases in fact this increased friction prevents or at least reduces
relative movements between the mattress cover and the mattress
during the use, therefore helping in keeping the mattress cover in
its right position provided initially, e.g. by the user when
applying the cover to the mattress.
[0014] Even if the covering sheets disclosed in our above mentioned
patent applications function well, particularly in terms of
protection, they can be improved in terms of further benefits for
the user by providing them with odour reduction properties, and
also preferably with active agents releasing properties. While
systems for releasing active agents such as perfumes, etc. are
known in the art and also in the field of covering sheets for
bedding articles, see for example WO 99/17643, and while odour
control means are known in the art and particularly in the field of
absorbent articles such as sanitary napkins, disposable diapers,
incontinence products, etc., it is not known a disposable covering
sheet, particularly for bedding items such as mattresses, pillows,
etc. which is moisture vapour permeable, liquid impermeable and has
specific odour controlling properties, preferably combined with
active agents releasing properties.
SUMMARY OF THE INVENTION
[0015] A disposable, moisture vapour permeable, liquid impermeable,
covering sheet comprising at least a moisture vapour permeable
layer and a liquid impermeable but moisture vapour permeable film
layer preferably applied onto said moisture vapour permeable layer,
the covering sheet has specific odour controlling properties and,
if desired, also active agent releasing properties.
[0016] More specifically said covering sheet comprises odour
control means which are able to provide a malodour reduction of at
least 15% as indicated hereinafter, as measured according to the
Odour Control Test described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The drawings herein are intended to illustrate preferred
embodiments of the present invention, but are not meant to limit in
any way its scope.
[0018] FIG. 1 is a schematic plan view of a disposable mattress
cover according to the present invention.
[0019] FIG. 2 is a cross-sectional view of the disposable mattress
cover of FIG. I taken along the line A-A.
[0020] FIG. 3 illustrates the mattress cover applied to a
mattress.
DETAILED DESCRIPTION OF THE INVENTION
[0021] According to the present invention, a disposable, moisture
vapour permeable, liquid impermeable covering sheet is provided
which comprises at least a moisture vapour permeable layer and a
liquid impermeable but moisture vapour permeable film layer
comprising a highly processable thermoplastic composition having
moisture vapour permeability. Said covering sheet offers a further
benefit to the user, particularly when used as a covering sheet for
bedding articles by providing odour control properties and, if
desired, also active agent releasing properties.
[0022] Covering sheets according to the present invention can be
used to cover and protect different articles in a variety of fields
for both domestic, industrial or institutional usage; such usages
include, but are not limited to, covering sheets for headrests and
seats, both for domestic use or institutional use, and for use in
the transportation industry, table covers of dining sets, covering
sheets for medical examination tables, covering sheets for
furniture, etc.
[0023] The preferred utilization of the covering sheets herein is
in bedding articles, both for domestic and institutional usage. The
covering sheets of the present invention are particularly useful
for use in disposable bed mattress covers and pillow cases or
covers.
[0024] The term "mattress", as used therein, refers to a fabric
case filled with resilient material, such as for example cotton,
hair, feathers, foam rubber, or an arrangement of coil springs, and
therefore comprises particularly bed mattresses, but also pillows,
cushions, comforters, duvets, upholstered portions of beds (such as
headboards), or of sofas or armchairs. Consequently, even if the
present invention will be described with particular reference to a
disposable covering sheet for bedding items in the form of a
mattress cover, it is not meant to limit in any way its scope to
mattress covers.
[0025] Referring particularly to mattresses it is generally known
that each mattress every year "absorbs" from about 45 kilos to
about 80 kilos of sweat and about 150 grams of skin scales. In
addition to this, millions of mites generally live in the mattress.
Another problem is that accidental staining is practically
unavoidable. Usually consumers are aware of the above problems and,
in fact, most of them use reusable mattress covers which usually
are made from cotton. But these covers do not solve the above
problems and, in particular, they are not capable of providing an
effective action of odour reduction, both towards odours already
present in the mattress, and which can be released in the
environment and smelled by the user, and odours, typically body
odours, which instead can be transmitted to the mattress, for
example by means of bodily fluids, typically sweat, as explained
above, absorbed by the mattress during the use.
[0026] The disposable covering sheet of the present invention
consists in a laminate of different layers comprising at least a
first moisture vapour permeable layer and a second liquid
impermeable but moisture vapour permeable film layer of
thermoplastic composition bonded onto said first layer, i.e. the
laminate preferably consists of at least two bonded layers giving
rise to a composite structure.
[0027] If more film layers of thermoplastic compositions are
utilised in a composite structure in combination with one or more
other moisture vapour permeable layers to create a layered moisture
vapour permeable, liquid impermeable composite structure, each film
layer can be made of a same specific thermoplastic composition, or
of different specific thermoplastic compositions.
[0028] The above composite structure can involve at least one
component, typically the film layer, of the thermoplastic
composition in combination with one or more other moisture vapour
permeable layers. Such moisture vapour permeable materials include,
but are not limited to: fibres, fibrous batts, non-wovens, wovens,
papers, micro-porous or porous membranes, films such as polymeric
films, perforated or apertured films and papers, macroscopically
expanded films, cloth, etc.
[0029] Said other components may be non-absorbent, absorbent,
liquid-containing, etc.
[0030] The composite structures of the covering sheets described
above have a moisture vapour transfer rate (WVTR) of at least 400
g/m.sup.2.multidot.24 h, more preferably at least 500
g/m.sup.2.multidot.24 h, and most preferably at least 600
g/m.sup.2.multidot.24 h, but they are impermeable to liquids.
[0031] According to a particularly preferred embodiment of the
present invention the disposable, moisture vapour permeable, liquid
impermeable mattress cover comprises a composite structure
comprising a film layer of the thermoplastic composition applied
onto a moisture vapour permeable substrate, wherein said film layer
is intended, in use, to directly contact the mattress. The moisture
vapour permeable substrate preferably comprises a fibrous layer,
e.g. a nonwoven layer onto which the thermoplastic composition is
applied in a continuous layer or film by means of known means, e.g.
preferably by hot melt coating.
[0032] A disposable, moisture vapour permeable, liquid impermeable
mattress cover comprising a moisture vapour permeable, liquid
impermeable structure in turn comprising a layer of the
thermoplastic composition which is intended, in use, to directly
contact a mattress, can have any shape and arrangement which is
known in the art, and which is suitable for its intended use.
[0033] For example, if the mattress consists of a standard bed
mattress, the mattress cover can be a substantially rectangular
flat sheet with elastic strings at the corners, or alternatively
with integrally elasticised corners, as described in FR 2747899.
The rectangular sheet typically has suitable dimensions in order to
completely cover at least the upper surface of the bed mattress,
and preferably, as in the latter embodiment referred to above, also
the side surfaces thereof, wherein the elastic strings or the
elasticised corners provide for a suitable releasable connection,
in a way known in the art, to the mattress. Alternative
configurations where the mattress cover has a suitable shape and
size in order to completely encase a mattress are also possible.
This latter configuration could be preferred when the mattress
cover, in addition to liquid imperviousness and moisture vapour
permeability, should also provide a total barrier against dust
mites and related allergens.
[0034] Preferably, as shown in the herein drawings, a disposable
mattress cover comprises a rectangular blanket made according to
the present invention. In particular, the disposable, moisture
vapour permeable, liquid impermeable blanket is formed by a
topsheet 1, which is preferably a moisture vapour permeable fibrous
layer, and a backsheet 2, which is a liquid impermeable but
moisture vapour permeable film layer of a thermoplastic composition
laminated onto said topsheet 1 in order to form a two-layer
composite structure. The backsheet 2 is intended to face and to be
in direct contact with the top of a mattress 4, while the topsheet
1 is intended to face the user.
[0035] The thermoplastic compositions can provide a certain degree
of residual tackiness to the backsheet 2. In turn, this tackiness
prevents or at least reduces relative movements between the
mattress cover and the mattress 4 during use, therefore helping in
keeping the mattress cover in its right position provided by the
user initially. In any case and if preferred, the mattress cover
can have no residual tackiness by suitably selecting the
thermoplastic compositions or by neutralising any residual
tackiness with known means, e.g. talcum powder. This tackiness can
be also useful for incorporating the odour control materials and
the active agents in the mattress cover according to the present
invention.
[0036] For assisting the user to put the mattress cover on the
mattress in the right position but also for fixing the mattress
cover to the mattress in a stable manner adhesive means 3 are
provided, as shown in the drawings. The adhesive means 3 can be one
or more stripes of a conventional pressure sensitive adhesive
covered by a release liner for protecting the adhesive before use,
as utilised, for example, in the manufacture of the panty fastening
adhesive patch of commercial sanitary napkins, or pieces of double
sided adhesive tapes, etc.
[0037] As shown in FIG. 3, the mattress cover has suitable
dimensions to completely cover at least the top surface and
partially the longitudinal sides 6 of the mattress 4, while
adhesive means 3 are preferably attached to the longitudinal sides
6 of the mattress 4.
[0038] Any other suitable shape or arrangement for a mattress cover
according to the present invention is also possible, depending on
the particular mattress type, shape and dimensions, and on the
intended use of the mattress cover.
[0039] Preferably the disposable, moisture vapour permeable, liquid
impermeable covering sheet of the present invention, when used as a
mattress cover or a pillow cover, has a surface area ranging from
15.0 m.sup.2 to 0.3 m.sup.2, preferably from 8.0 m.sup.2 to 0.5
m.sup.2. Most preferably, particularly in the case of a mattress
cover, said surface area is from 5.0 m.sup.2 to 1.0 m.sup.2.
[0040] Suitable thermoplastic compositions for the backsheet 2 can
be those disclosed in the European patent applications EP 963760
and EP 964026, already mentioned in the background of the
invention, but other compositions which form monolithic breathable
films can be utilised.
[0041] Residual tackiness of the thermoplastic composition can be
advantageously provided by the selection of the tackifying resin;
indeed the thermoplastic compositions described in the above
applications typically include resins or blends of tackifying
resins. Preferred resins, which may be present by up to 50% by
weight of the thermoplastic composition, may be selected from
rosins and rosin esters, hydrocarbon resins, aliphatic resins,
terpene and terpene-phenolic resins, aromatic resins, synthetic C5
resins, mixtures of synthetic C5-C9 resins, and mixtures
thereof.
[0042] By suitably selecting the tackifier resin or blend of
tackifier resins, it is possible to adjust the residual tackiness
at room temperature of the thermoplastic composition, and therefore
of the layer formed from said thermoplastic composition, to the
extent that it has the typical characteristics of a pressure
sensitive adhesive.
[0043] Preferred tackifier resins, or blend of tackifier resins
still have a softening point of 125.degree. C. or less, and are
selected from the group consisting of rosin and rosin esters,
terpene-Phenolic resins, aromatic resins, and mixtures thereof.
[0044] More preferably, the thermoplastic compositions according to
the above mentioned applications comprise a blend of tackifier
resins, selected as described above, wherein moreover from 0% to
20%, preferably from 2% to 15%, by weight of said blend of
tackifier resins comprises a resin or blend of resins having a
softening point of less than 25.degree. C., and from 80% to 100%,
preferably from 85% to 98%, by weight of said blend of tackifier
resins comprises a resin or blend of resins having a softening
point of at least 70.degree. C.
[0045] Other thermoplastic compositions for the backsheet 2 are
those described in our European patent application No. 00116284.1,
filed on Aug. 10, 2000 with title: "Thermoplastic hydrophilic
polymeric compositions with improved adhesive properties for
moisture vapour permeable structures" (P&G Case CM2406F).
[0046] Monolithic films are preferred materials because they do not
allow the flow of moisture vapour through open pores or apertures
in the material, but do transfer substantial amounts of moisture
vapour through the film by absorbing water on one side of the film
where the moisture vapour concentration is higher, and desorbing or
evaporating it on the opposite side of the film where the moisture
vapour concentration is lower. Consequently, while they allow the
passage of moisture vapour, they are truly impermeable to liquids,
dust, etc.
[0047] Odour Control Means
[0048] According to the present invention the disposable covering
sheet for bedding items comprises as an essential component an
odour control means.
[0049] It is known that in use, articles, which come in direct or
indirect contact with human skin tend to acquire a variety of
compounds, for example volatile fatty acids (e.g. isovaleric acid),
ammonia, amines (e.g. triethylamine), fatty acids, sulphur
containing compounds (e.g. mercaptans, sulphides), alcohols,
ketones and aldehydes (e.g. furaldehyde) which release unpleasant
odours.
[0050] These compounds may be present in the bodily fluid or may be
produced after by fermentation.
[0051] A number of compounds, mixtures, compositions and the like
are known in the art to combat some of the unpleasant odours
referred to above many of which are based on adsorbents such as
activated carbon, clay and zeolites. Particularly, odour control
systems are known in the field of the art relating to articles for
absorbing bodily fluids such as sanitary napkins, pantiliners,
disposable diapers, incontinence pads, tampons, underarm pads and
the like.
[0052] Odour control means to be used in the covering sheets of the
present invention can be selected from the group consisting of
odour control materials, as mentioned below. These materials can be
typically classified according to the type of odour the material is
intended to combat. Odour can be chemically classified as being
acidic, basic or neutral.
[0053] Acidic odour controlling materials have a pH greater than 7
and typically include sodium carbonates, sodium bicarbonates,
sodium phosphates, particularly zinc and copper sulphates. Basic
odour controlling agents have a pH of less than 7 and include
compounds such as carboxylic acids such as citric acid, lactic
acid, boric acid, adipic acid and maleic acid. Neutral odour
controlling materials have a pH of approximately 7. Examples of
these types of compounds include activated carbons, clays,
zeolites, silicas, absorbent gelling materials and starches.
Neutral odour control materials and systems are disclosed for
example in EP 0348978, EP 0510619, WO 91/12029, WO 91/11977, WO
91/12030, WO 81/01643 and WO 96/06589. Also cyclodextrin and
derivatives can be used as described in U.S. Pat. No. 5,429,628.
Zeolites and cyclodextrins are particularly preferred as odour
control means in the covering sheets of the present invention.
[0054] Alternatively, the odour control systems can be categorised
with respect to the mechanism by which the malodour detection is
reduced or prevented. The above odour control agents typically
control odour detection by an adsorptive mechanism.
[0055] Therefore, odour control systems which chemically react with
malodorous compounds or with compounds which produce malodorous
degradation products thereby generating compounds lacking odour or
having an odour acceptable to consumers can also be utilised
herein. Useful agents include chelating agents selected from amino
carboxylates such as for example ethylenediamine-tetracetate, as
described for example in U.S. Pat. No. 4,356,190, amino
phosphonates such as ethylenediaminetetrakis
(methylene-phosphonates), polyfunctionally-substitutes aromatic
chelating agents as described in U.S. Pat. No. 3,812,044 and
mixture thereof. It is believed that the benefit of these compounds
is in part due to their exceptional ability to remove iron, copper,
calcium, magnesium and manganese ions present in the bodily fluid
and their degradation products by formation of chelates.
[0056] Another useful odour control system for use herein comprises
a buffer system, such as citric acid and sodium bicarbonate, sodium
phosphate and sorbic acid buffer systems. Also buffer systems
having a pH from 7 to 10 as described for example in WO 94/25077
can be used herein.
[0057] An alternative odour control system utilises ion exchange
resins as those described in U.S. Pat. No. 4,289,513 and U.S. Pat.
No. 3,340,875.
[0058] Also so called anti perspirant such aluminium salts for
example aluminium chloridrate and aluminium sulphate and
antimicrobics such as Triclosan and benzoic, propionic and sorbic
acids for example can also be used as odour control agents. Such
agents are described in "The Chemistry and Manufacture of
Cosmetics", by W. H. Mueller and R. P. Quatrale and "The Journal of
Investigative Dermatology, Vol. 88, N. 3, March Suppl. 1987,
entitled "Skin Microflora", by J. J. Leydon, K. D. McGinley et
al.
[0059] Other useful odour control agents are enzyme blocking agents
as described in Cosm. And Toil. 95, 48, 1980, in "Non
microbiological deudourising agents" by R. Osberghaus such as
triethyl cytrate and odour adsorbers for example zinc ricinoleate
as described in Cosmesi Funzionale, pages 465-498, ED. Singerga,
1988, by G. Proserpio.
[0060] Further useful art can be found in the following patent
publications:
1 Publication number Title EP-0515477 High capacity odor
controlling compositions EP-0515503 Carbon containing odor
controlling compositions EP-0515473 Odor controlling compositions
and articles EP-0691856 Odor controlling absorbent articles
containing small particle size uncomplexed cyclodextrin and fluid
absorbing material EP-0691857 Odor controlling absorbent articles
which provide a positive scent signal through cyclodextrin/perfume
inclusion complexes and/or solid cellular matrix perfume EP-0749295
Catamenials containing an antibacterial agent in an apertured
topsheet for odor control EP-959852 Sanitary napkin with
perfume-bearing microcapsule adhesive WO98/10861 Modified Porous
starch WO98/26808 Absorbent articles with odor control system
EP-695197 Odour control material US4385632 Gemicidal absorbent body
WO96/06589 Bentonite as odors control material EP-0811387 Feminine
hygiene absorbent products having a zeolite and silica odor control
system WO97/46192 Absorbent articles having an odor control system
comprising silica, zeolite and AGM WO97/46191 Absorbent article
having an odor control system comprising a chelating agent and an
odor absorbing agent EP-0811391 Absorbent article having a odor
control system comprising a chelating agent W097/46187 Absorbent
article comprising a polyfunctionally substituted aromatic
chelating agent for odor control W097/46188 Absorbent article
having an odor control system of zeolite and silica in close
physical proximity EP-0811388 Activated carbon-free absorbent
articles having a silica and zeolite odor control system EP-0813848
Breathable absorbent articles having odor control EP-0811392
Breathable absorbent article having a chelating agent- based
odor-control system EP-0811389 Breathable absorbent articles having
a silica-based odor control system EP-0891708 Anti-microbic agent
WO99/30754 Compacted odor control particles for use in absorbent
articles EP-937467 Doped odor controlling materials
[0061] In addition, other materials can be used as odour control
agents selected from the group consisting of antimicrobics,
oxidising agents, lactic acid producing bacillus, chitin,
chitosan.
[0062] The odour control agent of the present invention is
preferably selected from the above agents or combinations thereof,
wherein zeolites and cyclodextrin are preferred, but it should be
noted that other known odour control agents or systems can be
used.
[0063] The odour control system can be incorporated in the article
of the present invention by any of the methods disclosed in the
art.
[0064] Active Agents Releasing System
[0065] According to the present invention the disposable covering
sheet can also optionally comprise an active agents releasing
system in addition to the odour control means.
[0066] Active materials such as perfumes, which will release a
fragrance during their utilisation, can be utilised.
[0067] As used herein the term perfume means any odoriferous
material. In general, such materials are characterised by a vapour
pressure less than atmospheric pressure at ambient temperatures.
The perfume employed herein will most often be liquid at ambient
temperatures, but also can be solids such as the various
camphoraceous perfumes known in the art. A wide variety of
chemicals are known for perfumery uses, including materials such as
aldehydes, ketones, esters and the like. More commonly, naturally
occurring plant and animal oils and exudates comprising complex
mixtures of various chemical components are known for use as
perfumes, and such materials can be used herein. The perfumes
herein can be relatively simple in their composition or can
comprise highly sophisticated, complex mixtures of natural and
synthetic chemical components, all chosen to provide any desired
odour.
[0068] Typical perfumes herein can comprise, for example,
woody/earthy bases containing exotic materials such as sandalwood
oil, civet, patchouli oil and the like.
[0069] The perfumes herein can be of a light, floral fragrance,
e.g., rose extract, violet extract and the like. The perfumes
herein can be formulated to provide desirable fruity odours, e.g.,
lime, lemon, orange and the like.
[0070] Perfume materials are described more fully in S. Arctander,
Perfume Flavors and Chemicals. Vols. I and II. Aurthor, Montclair,
N. J., and the Merck Index, 8th Edition, Merck & Co., Inc.
Rahway, N.J.
[0071] In short, any chemically compatible material which exudes a
pleasant or otherwise desirable odour can be used in the perfumed
particles herein to provide a desirable odour when applied to
articles according to the present invention.
[0072] Perfumes which are normally solid can also be employed in
the present invention. These may be admixed with a liquefying agent
such as a solvent prior to incorporation into the articles of the
present invention by spraying, or may be simply melted and
incorporated in the film layer, as long as the perfume does not
sublime or decompose upon heating.
[0073] In addition, starch encapsulated perfumes, as described for
example in GB 1464616, can be preferably utilised. Encapsulation
allows a long lasting release of perfumes. Useful preferred active
agents are those disclosed in WO 00/02987, EP 0971021, EP 0971024,
and EP 0971025 which describe, inter alias, a product of reaction
between a primary amine and a perfume component. By utilising the
product of reaction described by the above patent applications, the
release of the active (for example, a perfume component) lasts for
a longer period of time than by the use of the active alone
itself.
[0074] It should be noted that active agents are not limited to
perfumes but other know active agents selected from insecticides,
deodorants, volatile therapeutic materials, aromatic oils and
mixtures thereof can be utilised for providing a benefit to the
user.
[0075] Volatile therapeutic materials include materials which
assist in keeping nasal passages clear of congestion in cold or
allergy sufferers, for example menthol, camphor, eucalyptus oil and
similar oil, as well as other materials which can benefit a patient
by absorption through the nasal passages and the lungs as a result
of prolonged exposure. The therapeutic materials may include
extracts of herbs and the like which help the user to relax or to
sleep. Aromatic oils, such as those referred to as `aromatherapy
oils` may also be used into the substrate.
[0076] The active agent, if present, is preferably selected from
any of the above agents or combinations thereof.
[0077] The active agent or agents can be incorporated in the
article of the present invention by any of the methods disclosed in
the art.
[0078] Other Characteristics
[0079] A moisture vapour permeable, liquid impervious layer can be
formed from a suitable thermoplastic composition by coating said
thermoplastic composition onto a substrate.
[0080] A process for making a film layer from a thermoplastic
composition typically comprises the steps of providing said
composition, heating it to make it flowable, and coating said
composition in the molten state onto a substrate in a layer having
the desired thickness. It should be noted that odour control
materials and active agents can be included in the thermoplastic
composition. Alternatively, they can be applied onto the surface of
the film or layer made of the thermoplastic composition, e.g.
directly adhered thereto by taking advantage of the tackiness of
the composition immediately or shortly after formation of the layer
or film as mentioned above.
[0081] In accordance with the present invention, a moisture vapour
permeable, water impervious composite is formed which comprises the
thermoplastic composition and a substrate onto which said
thermoplastic composition is coated, wherein the substrate is also
moisture vapour permeable.
[0082] Such embodiment provides a moisture vapour permeable, liquid
impervious composite structure wherein the film layer formed from
the thermoplastic composition is firmly bonded to the substrate
while providing the required performance for liquid barrier and
hence could be advantageously provided as thinly as possible. In
this manner such embodiment provides a moisture vapour permeable,
liquid impervious composite structure wherein the contribution of
the film layer formed from the thermoplastic composition to the
performance of the composite material resides mainly in the
provision of a liquid barrier. The remaining performance physical
criterion being preferably provided by the provided substrate, that
therefore preferably acts also as a support layer. However it
should be noted that the film layer does not need to be as thin as
possible in any application because the thermoplastic compositions,
according to our before mentioned patent applications, provide high
breathability (high WVTR) also in the case of thicker film layers.
Typical thickness of the film layer of the thermoplastic
composition applied onto a suitable substrate to form a composite
structure according to the present invention range from 2 .mu.m to
200 .mu.m.
[0083] The substrate, or support layer may be any useful layer
which is also moisture vapour permeable, preferably having a
moisture vapour permeability of at least 400 g/m.sup.2.multidot.24
h, more preferably at least 500 g/m.sup.2.multidot.24 h, and most
preferably at least 600 g/m.sup.2.multidot.24 h.
[0084] Preferred support layers for use herein include woven and
nonwoven layers, most preferably hydrophobic fibrous layers such as
hydrophobic nonwoven. As for non limiting examples, a SMS
(Spunbonded-Meltblown-Spunb- onded) hydrophobic 100% polypropylene
nonwoven of 17 g/m.sup.2 or of 25 g/m.sup.2 both commercialised
under the code G17AI0, MD3000, respectively, by Corovin--BBA
Nonwovens Group (Germany), or a spunlaced nonwoven of 50 g/m.sup.2
commercialised under the code TJET C500 by Tecnofibra (Italy)
function well.
[0085] Suitable substrates for use herein as further layers in the
structure according to the present invention could also include two
dimensional, planar micro and macro-porous films; macroscopically
expanded films; formed apertured films; nonwoven and woven layers.
Suitable macroscopically expanded films for use herein include
films as described in for example in U.S. Pat. No. 4,637,819 and
U.S. Pat. No. 4,591,523.
[0086] The structures of the preferred embodiment according to the
present invention are particularly advantageous as they allow the
possibility of providing a composite wherein the thermoplastic
composition may be applied onto the support substrate as a film
layer with the desired thickness. Typical coating conditions and
apparatuses known in the art for the direct coating of low
viscosities hot melts can be readily utilised in order to provide
the thermoplastic composition at the desired thickness.
[0087] A possible method for forming a composite laminate by
coating the thermoplastic composition onto a substrate acting as a
support layer is described in PCT application WO 96/25902.
[0088] At least at the coating temperature, the thermoplastic
composition in form of a layer preferably exhibits adhesive
properties on the supportive substrate in order to form the
preferred composite such that no additional adhesive is required to
achieve a permanent attachment between the thermoplastic
composition and the substrate.
[0089] A moisture vapour permeable, liquid impervious composite
structure formed by coating a thermoplastic hydrophilic composition
onto a suitable substrate finds particular utility as a structure
constituting a disposable, moisture vapour permeable, liquid
impermeable mattress cover according to the present invention.
EXAMPLE 1
[0090] A polyether-amide block copolymer available from Atofina
(France) commercialised under the trade name Pebax 2533 SN is
compounded with Tri Butyl Citrate (plasticiser) available from
Aldrich Co., Res A-2691 (tackifier resin) available from Hercules
Inc., Res A-2690 (tackifier resin) available from Hercules Inc.,
both resins described in our already mentioned European application
No. 00116284.1, and Irganox 1010 (anti oxidant agent) available
from Ciba-Geigy.
[0091] The final formulation in percent by weight has the following
composition:
2 44% Pebax 2533 SN 25% Tri Butyl Citrate 15% Res A-2691 15% Res
A-2690 1% Irganox 1010
[0092] The blend is melt extruded to obtain a film having a basis
weight of 20 g/m.sup.2. The film is laminated directly onto a
substrate constituted by a SMS (Spunbonded-Meltblown-Spunbonded
structure) hydrophobic 100% polypropylene nonwoven 25 g/m.sup.2
(support layer) commercialised under the trade name MD3000,
available form Corovin--BBA Nonwovens Group (Germany). The
composite has a WVTR (Water Vapour Transmission Rate) of 846
g/m.sup.2.multidot.24 h.
[0093] The composite structure is used to produce a mattress cover,
e.g. a bed mattress cover as illustrated in the herein drawings. It
has a flat rectangular shape with suitable dimensions to completely
cover at least the upper surface of a bed mattress, wherein the
film layer 2 of thermoplastic composition is intended to face, in
use, the mattress 4, and to directly contact it. In particular, the
dimension are: 1.75 m (width) and 2.10 m (length) to completely
cover the upper surface of a bed mattress 4 and partially its
longitudinal sides 6 as indicated in FIG. 3. The corners of the
mattress cover are fixed to the corners of the bed mattress by
adhesive tapes 3, after detaching the release liners 5 which
protect the adhesive surface of adhesive tapes before use. The
adhesive tapes 3 are pieces of double sided adhesive tape, each
having a width of 50 mm and a length of 300 mm, available from
Avery Dennison Co. under FF310 code.
[0094] It should be noted that other adhesive tapes could be
provided along the longitudinal edges of the mattress cover for
better fixing it to the longitudinal sides 6 of a bed mattress
4.
[0095] Samples of the above material for mattress cover having 10
cm.times.10 cm dimensions were sprayed with different amounts of a
water solution of cyclodextrin at 2% by weight to obtain two
different amounts of cyclodextrin in the samples, respectively 8
mg/sample (0.8 g/m.sup.2) and 16 mg/sample (1.6 g/m.sup.2). The
cyclodextrin was a beta cyclodextrin available under the code 28707
from Fluka Div. of Sigma-Aldrich Co.
[0096] Odour Control Test
[0097] An amount of 0.5 ml of malodorant solution was added to a
cup whose opening, having a diameter of 50 mm, was covered and
suitably sealed with the treated samples (i.e. samples containing
the odour control material) and with a sample having the same
structure, but without odour control material.
[0098] The composition (by weight) of the malodorant solution or
mixture was:
3 distilled water 99.000% sodium chloride 0.700% butyric acid
0.040% ascorbic acid 0.040% lactic acid 0.100% formic acid 0.009%
propionic acid 0.006% capronic acid 0.004% urea 0.101%
[0099] The cups with the samples were put into an oven at
30.degree. C. and 75% relative humidity. After two hours a panel of
trained odor graders assessed malodour intensity over the samples
on a scale from 0 to 10. In particular intensity scale was:
4 10 high 9 high 8 high 7 high 6 medium 5 medium 4 medium 3 low 2
low 1 low 0 No odour
[0100] Each expert grader gave the number of odour intensity after
having smelled the treated and untreated samples, and an average
value was obtained.
[0101] The results are reported in the following table as
percentage of malodour (odour intensity) versus the reference which
was the same as the described samples but not treated with the
cyclodextrin solution. The average of the results of the tests
performed are reported, wherein the odour intensities are expressed
as percentages related to the odour intensity of the reference,
which has been considered to correspond to 100%.
5 Sample Odour intensity % Reference 100 Sample with 0.8 g/m2 of
cyclodextrin 95 Sample with 1.6 g/m2 of cyclodextrin 75
[0102] As it is evident from the above data adding 1.6 g/m2 of
cyclodextrin was able to reduce the odour intensity by 25% which
can give a significant benefit to the user in terms of malodour
reduction, while adding 0.8 g/m2 of cyclodextrin, which reduced the
odour intensity by 5%, cannot give the same benefit. As a matter of
fact, it was surprisingly discovered that an odour control system
to be effective and, consequently, to be able of giving a consumer
benefit in terms of malodour reduction, should reduce the odor
intensity (malodour reduction) of at least 15%.
EXAMPLE 2
[0103] As example 1 except that this time zeolite ZP-4A available
from Silkem d.o.o. (Slovenija) was added into the thermoplastic
blend composition in proportion of 1% by weight of composition as
odour control material.
[0104] When evaluated for malodour reduction in the same manner as
in the example 1 the sample of mattress cover comprising the
composition containing 1% of zeolite gave a malodour reduction of
29% compared to the sample of mattress cover of the same
composition but not containing zeolite.
[0105] Further increase of the amount of zeolite gave no
significant further advantage. In fact at a zeolite level of 2% the
malodour reduction was 30%.
[0106] A decrease of zeolite level at 0.5% gave no advantage. In
fact at a zeolite level of 0.5% the malodour reduction was 5%
only.
EXAMPLE 3
[0107] A polyether-amide block copolymer available from Atofina
(France) commercialised under the trade name Pebax 2533 SN01 is
compounded with Citroflex 2 (plasticiser) available from Reilly
Chemical Co., Ketjenflex 8 (plasticizer) available from Akzo Nobel
Co., Irganox 1010 and Irganox PS 800 (both anti oxidant agents)
available from Ciba-Geigy, and ZP-4 A (zeolite-as odour control
material) available from Silkem d.o.o. (Slovenija).
[0108] The final formulation in percent by weight has the following
composition:
6 50.00% Pebax 2533 SN 24.35% Citroflex 2 24.35% Ketjenflex 8 0.15%
Irganox 1010 0.15% Irganox PS 800 1.00% ZP-4 A
[0109] The blend is melt extruded to obtain a film having a basis
weight of 20 g/m.sup.2. The film is laminated directly onto a
substrate constituted by a SMS (Spunbonded-Meltblown-Spunbonded
structure) hydrophobic 100% polypropylene nonwoven 17 g/m.sup.2
(support layer) commercialised under the trade name G17AI0,
available form Corovin--BBA Nonwovens Group (Germany). The
composite has a WVTR of 1907 g/m.sup.2.multidot.24 h. Then a
conventional starch encapsulated perfume (50% active agent and 50%
starch) having fresh notes was mixed with talcum and the mixture
was applied at a level of 3.80 g/m.sup.2 (with a starch
encapsulated perfume at a level of 0.3 g/m.sup.2) and fixed onto
the film by the adhesiveness (i.e. residual tackiness) of the film
itself.
[0110] The composite structure is used to produce a mattress cover,
e.g. a bed mattress cover as previously described in the example
1.
[0111] The above disposable, moisture vapour permeable, liquid
impervious mattress cover demonstrated in confidential in-use tests
to be able to decrease malodours while, at the same time, releasing
perfume and smelling fresh for many days.
[0112] Tests.
[0113] Moisture vapour permeability is measured as Water Vapour
Transmission Rate (WVTR) at 23.degree. C. and 50% relative humidity
according to the modified ASTM E-96 "Upright Cup" method. The only
modification to the standard ASTM E-96 "Upright Cup" method
consists in a change in the height of the air gap between the
sample and the water surface in the cup, which height is 3 mm
.+-.0.5 mm, instead of 19 mm .+-.2.5 mm, as specified in the
standard test method.
[0114] The Odour Control Test is illustrated in the context of the
example 1.
* * * * *