[0001] The present invention relates to a sanitary fabric made of two particular types of
material, of different texture on both sides, created with TREVIRA CS yarn, coated
with polyurethane and with sanitized additives; furthermore, the invention refers
to the process for producing such fabric.
[0002] From a technical point of view, the following types of fabric are known:
- PVC based coatings both on cotton and synthetic fibres;
- Fire-proof treated fabrics;
- Anti-bacterial and anti-allergic treated fabrics; and patents US-A-5414024, US-A-5376208,
WO-A-03023108, GB-A-2114509.
[0003] However, these are not satisfactory and have the following problems:
- they do not allow a purely hospital use and in particular regarding problems related
to the human tissue when it presents itself with bedsores; the fabric has to be transpirant
in order to allow the contact between the air and the human tissue;
- the infective and allergic agents, such as mites and scabies, are not physically blocked
if the fabric has to be transpirant;
- the fabric is subjected to a fire-proof treatment that does not remain after repeated
washes, that is the fabrics are made fire-proof, but they are not intrinsically fire-proof.
[0004] Object of the present invention is therefore solving the above-mentioned prior art
problems, by providing a sanitary fabric made of the combination of two fabrics, of
different texture on both sides, manufactured with TREVIRA CS yarn, coated with polyurethane
and with sanitized additives that can guarantee a greater protection against those
agents that are considered to be the main aggressors both for used fabric as well
as for the user.
[0005] A further object of the present invention is providing a sanitary fabric with fire-proof
features.
[0006] Additionally, an object of the present invention is providing a production process
of a sanitary fabric. The above-mentioned objects, as well as other objects and advantages
of the invention, as will result from the description, will be achieved with a fabric
like the one described in claim 1. Moreover, the above-mentioned objects, as well
as other objects and advantages of the invention, can be achieved through a production
process of a sanitary material as described in claim 15. Preferred embodiments and
non-trivial variations are the subject of the relevant claims.
[0007] The present invention will be better described by some preferred embodiments thereof,
provided as a nonlimiting example, with reference to the enclosed drawings, in which:
- Fig. 1 shows a sectional view of an embodiment of the fabric according to the present
invention; and
- Fig. 2 shows a sectional view of a single-knit machine producer of micro-sponges according
to the present invention.
[0008] With reference to the above Figures, a particular embodiment of the present invention
is shown and described here.
[0009] Referring in particular to Fig. 1, the fabric is composed, according to the present
invention, of a layer 1 of micro-sponge together with another layer 2 coated with
polyurethane.
[0010] The fabric 1 is preferably made of a 83 denier fire-proof (decitex measure equal
to 83 g / 1000 m, equivalent to a measure in denier equal to 76 g / 9000 m) TREVIRA
CS yarn that, supplied to a 20 single-knit machine as in Figure 2, generates a fabric
called " bedspread micro-sponge".
[0011] The basis weight of the fabric 1 ranges by preference, between 100 and 150 g/m; a
sub-optimum confidence interval for the production of "bedspread micro-sponge" is
included between 125 and 135 g/m; the excellent one, which also represents the custom
in the production process, is equal to 130 g/m.
[0012] As the "bedspread micro-sponge" is intended to be covered on a surface with a coating
that grants its peculiar features, presents interlaces of different threads on both
sides, as one is intended to be coated and the other one remains exposed.
[0013] The side of the exposed micro-sponge fabric's layer appears like a micro-sponge,
essentially carrying therefore, the same features of towels' fabric, but with slots
of the size preferably equal to 0.7 mm.
[0014] The side of the fabric's layer made of micro-sponge material 1 intended instead to
be covered by the layer coated in polyurethane 2 is in a simple thread, commonly known
as "Jersey". The side coated in polyurethane is obtained by a solution and is made
of dry resin and a solvent. The resin is in polyurethane and has a polietheric nature
necessary to resist to dry cleaning processes.
[0015] The layer with a polyurethane coating has been added with additives anti-mite and
mould, possibly Ultra Fresh additives mixed in the polyurethane resin.
[0016] The fabric according to the present invention is resistant to high temperatures,
water-proof and transpirant.
[0017] The thickness is measured as a distance between the two measuring planes of a feeler
gauge, due to the interposition of the coated stand. The thickness is equal to 0.7
mm ± 0.3 (UNI Regulations 4817 - 7805).
[0018] The mass, expressed in grams per square metre of the support, is equal to 230g/m
with a variance equal to about 20% (UNI Regulations 4818 pt 3).
[0019] The usable height is the width of a piece of cloth limited to the two points between
which the coated stand meets the specific requirements (160 cm max) (UNI Regulations
4817).
[0020] Resistance tests have highlighted the following features.
[0021] In case of traction, the ultimate strength, that is the maximum strength needed to
cause the breaking of the stand of a sample prototype, in strung is greater or equal
to 359 N; as far as the one in yarn is concerned, it is greater or equal to 130 N
(UNI Regulations 4818, pt 6).
[0022] In case of stretching, determined in % on the original piece, it is measured as an
increase in the distance between two reference points. With such definition and subjecting
the sample prototype to a specific weight, the resistance of the stretching in strung
is equal to 55% ÷75%, while in yarn is equal to 190% - 210. (UNI Regulations 4818,
pt 6).
[0023] The laceration test is defined as the traction power needed to make an arranged breaking
point progress in a sample prototype. The resistance of the laceration in strung is
greater or equal to 130N while the one in yarn is greater or equal to 59N (UNI Regulations
4818, part 9 method a).
[0024] The repeated bending test is defined as the coating's ability not to crack after
a series of bendings under test conditions. The invention resists for a number of
cycles greater or equal to 200,000 both on the knitted side as well as on the polyurethane
one (UNI regulations 4818, part 12).
[0025] The abrasion test (or wear and tear) measures the ability of its coating to resist
to a mechanical rubbing action which progressively tends to remove the material from
its surface. Such ability is greater than 1,000 cycles on the fabric side 1 and it
is greater than 500 cycles on the side coated with polyurethane 2 with a weight of
1 kilo on a convex profile (UNI Regulations 4818, part 159).
[0026] The resistance to crease is defined as the capacity of its coating to resist to a
mechanical action which tends to repeatedly fold the fabric. Such resistance is greater
or equal to 100,000 cycles.
[0027] The water-proof feature consists in the ability of the coated supporting device not
to allow the water to go through all its thickness, when it is subjected to alternating
bendings for a certain number of cycles.
[0028] In the case of a new fabric, the impermeability is guaranteed over the 36 hours with
a water column equal to 140 cm.
[0029] In case of a fabric subjected to a first wash and to a drying process of about 1
hour at 135°C, the impermeability is guaranteed over the 36 hours with a water column
equal to 50 cm.
[0030] In the instance of a second wash and drying process of one hour at 135°C, the impermeability
is guaranteed over the 36 hours with a water column equal to 45 cm.
[0031] In the instance of a third wash and drying process of one hour at 135°C, the impermeability
is guaranteed over the 36 hours with a water column equal to 40 cm.
[0032] In the instance of a forth, fifth, and sixth wash and drying process of one hour
at 135°C, the impermeability is guaranteed over the 36 hours with a water column equal
to 23 cm.
[0033] The fire resistance is tested through the definition of the propagation speed of
the flame on horizontal sample prototypes.
[0034] Such test has shown that the propagation is lower than 100 mm/min (UNI Regulation
4818, pt 19).
[0035] The resistance to hydrolysis is the ability of the coating to keep unaltered as much
as possible its mechanical features after a wet treatment aimed at quickly reproducing
the used conditions.
[0036] The invention has shown such skills after having being subjected to a water treatment
at 90°C for 16 hours through repeated flexions (UNI Regulations 4818, pt.13).
[0037] The transpirability, measured in grams per square metre, expresses the quantity of
steam produced over a period of 24 hours in a square metre of fabric keeping its water-proof
features. On the sample prototypes the method INVERTER CUP has been used ((DIN Regulation
53122).
[0038] On a new fabric this test method has provided a transpirability equal to 2,300 g/m
of steam in 24 hrs. On a fabric after the third wash and drying of 1hr at 90°C of
tests has provided a transpirability equal to 3,700 g/m of steam in 24 hrs.
[0039] The antibacterial guarantee is defined as the ability of its coating to inhibit the
contact of the bacteria with the outside. The antibacterial treatment is preferably
provided by Ultrafresh.
[0040] Two parameters are defined in order to measure such guarantee; which are the contamination
area (ZC) that is the length of the contaminated area related to the specific test
and the inhibition to the (IC) area rate contact of free bacteria before the specific
test. As emerges from the following table 1 both sides of the fabric, based on the
present invention, show a good resistance against bacteria:
Table 1
Staphylococcus Aureus |
|
Z.C.(mm) |
I.C. (%) |
Coated with polyurethane |
>15 mm |
100% |
Not coated with polyurethane |
= 12 mm |
100% |
Aspergillus Niger |
|
Z.C.(mm) |
I.C. (%) |
Coated with polyurethane |
>3 mm |
100% |
Not coated with polyurethane |
=4 mm |
100% |
[0041] Favourably, specifically precautions are not requested, in relation to waste disposal
(normal garbage) and in relation to the preservation and storage of the fabric according
to the present invention.
[0042] The invention does not contain "phthalic acids" in a quantity greater than 5%.
[0043] The present invention also relates to a production process of the above-described
fabric. Referring to Figure 2, according to the present invention, the process takes
place with a circular 20 single-knit machine, for micro-sponge production, at 96 fall
line (therefore 96 yarn rolls). 48 of these machines are intended for the production
of the part of the "Jersey" type fabric which will be the side of the fabric 1 covered
by the layer coated with polyurethane 2; the remaining 48 yarn rolls are intended
to the micro-sponge part of fabric 1.
[0044] In order to obtain these two different sides, the machine which produces the fabric
has been favourably and purposely modified.
[0045] In particular, according to the present invention, the process provides the following
steps:
- loading the 96 yarn rolls on the machine 20 (48 for Jersey/48 for micro-sponge) in
order to start the production. Important parameters in this step are the tension of
the thread on the fall lines in micro-sponge (3 grams each both on Jersey falls and
on micro-sponge ones with a 30% scrap), slow speed (14 revolutions/min. with a difference
of 30%);
- producing a body tissue of fabric that presents itself like a sock ready for the following
processing;
- opening the fabric; from a body tissue, a fabric is created and it is then gathered
at stripe (technically striped or folded);
- cataloguing the fabrics, step in which the striped fabrics are put in order and inserted
into the carts by batch;
- supplying a second machine (not shown) called "Rameuse" with the fabric and thermally
fixing it (trim size);
- carrying out a first round in "foulard", that is the fabric goes in a tank containing
a solution of water and fabric conditioners;
- carrying out a second round of "squeezing" of the fabric, on rollers, with a pressure
which preferably ranges between 1 and 5 bar. The "squeezing" process allows the enzymatic
oils, contained in the Trevira CS, to be partially eliminated (from 10 to 100%);
- completely unrolling the selvage in order to be drawn on the pulling chain weaved
by the second machine "Rameuse";
- spreading some vinyl adhesive on the edges of the fabric to avoid curling during the
process which could stop;
- fixing the fabric with heat, step in which the fabric undergoes oven heat treatment
with temperatures preferably between 190°C and 210°C. After this treatment, the product
is ready to be coated;
- proceeding with the coating of the fabric to transfer; during this phase, the coating
takes place on paper (preferably on silicone paper), which also gives that particular
look to the end product (smooth and opaque) and it is also makes the polyurethane
grow into different layers. This phase takes place on a third machine with three heads
of coating, it keeps the fabric pulled in order to get an even distribution of resin
on paper. A coating knife monitors the quantity of resin distributed on the paper
thanks to some micro-beams with weight measuring units.
[0046] This solution used by all three heads of spreading, it is composed by 35% of dry
resin and 65% of solvent in weight; this mixture will later be called polyurethane.
[0047] A 0.5% of Ultra Fresh® in weight is preferably added to the solution.
[0048] The above-mentioned step of fabric coating to transfer includes the following steps:
- spreading in the first head polyether used as skin, applied on silicon paper resistant
to solvents and to high temperatures (paper with grammage of 180 g/m2). Each head works with the temperature between 140 and 160 °C with a tolerance preferably
between 145 e 155 °C that allows the polymerization of the above mentioned solution.
The oven allows the evaporation of the solvent contained in the resin. This step distributes
between 40 and 10 g/m2 of dry polyurethane with an interval between 22 and 18 g/m2, but more preferably equal to a 20g/m2;
- spreading another layer of the solution on the second head, by applying it on the
first layer of the first head. Also this head works with a heat treatment that allows
the polymerization of the solution at the temperature between 140 and 160 °C, with
a tolerance preferably between 145 e 155 °C, but more preferably equal to 150°C. The
oven allows the evaporation of the solvent contained in the resin. This phase distributes
between 50 and 10 g/m2 of dry polyurethane with an interval between 30 and 20 g/m2, but more preferably equal to a 25g/m2;
- coupling, in the third head, the fabric on "Jersey" side with a polymerized film added
to adhesive film. This treatment is then stabilized in the oven. The heat treatment
of the third head allows the polymerization on the solution at a temperature preferably
between 140 and 160 °C, with a tolerance preferably between 145 and 155 °C, even better
a temperature of 150 °C. The oven makes the solvent that contains the resin evaporate.
This phase distributes between 50 and 10 g/m2 of dry polyurethane with an interval between 42 and 28 g/m2, but more preferably equal to a 35g/m2. The adhesive is mixed with melamine resin with acid and melamine. This mixture allows
a better resistance, both mechanical and chemical, respectively to the different types
of washing and to protect from the most common chemicals such as alcohol and other
chemical products used to clean hospital equipment. Advantageously, in all above spreading
steps, it is also possible to monitor the weight of solution spread on each square
meter of fabric, through rollers, head and tail, that pull the fabric in order to
keep it constantly pulled;
- removing the paper when the polyurethane touches the fabric.
[0049] Ultra Fresh® sanitization is mixed with polyurethane with a percentage between 0.1
and 1% with an interval preferably between 0.4 and 0.6%, more preferably equal to
0.5%.
[0050] The catalyst of melamine resin is mixed with a polyurethane of a percentage between
0.1 and 2% with and interval preferably between 0.3 and 1%, more preferably equal
to 0.5%.
[0051] The acid is mixed with polyurethane with a percentage between 0.01 and 0.5%, with
an interval preferably between 0.1 and 0.3%, more preferably equal to 0.2%; all percentage
are in solution.
[0052] Also, an isocyanate can be mixed with polyurethane with a percentage between 0.2
and 3% with an interval preferably between 1 and 2%, more preferably equal to 1.5%
in solution.
[0053] It is obvious that a lot of different variations and options can be added (i.e. different
shapes, dimensions, colors and parts with the same functionalities) always within
the scope of the invention as claimed in the attached claims.
[0054] The operation and the destination of use of the present invention will now be described.
[0055] According to this invention, the fabric can be used as bed sheets for hospital use,
un-washable and high temperature sterilizable.
[0056] The invention can also be used to make up covers for mattresses, washable and sterilizable
at high temperatures. There are also pillow covers for hospital and not, that are
washable and sterilizable at high temperatures.
[0057] This fabric can be used in hospitals, as cover of padding, fabric for clothes, etc.,
or where a soft, elastic, fireproof, waterproof, breathable fabric, that is resistant
both to chemical and to bacterial aggressions has to be used.
1. Sanitary fabric composed of a layer of micro sponge fabric (1) and a layer (2) that
is spread in polyurethane, characterized in that said layer (2) that is spread in polyurethane is composed of a solution of dry resin,
anti-mites additives, anti-mildew additives and solvent.
2. Sanitary fabric according to claim 1, characterised in that said dry resin is a polyurethane resin of polyether nature.
3. Sanitary fabric according to claim 1, characterised in that said anti-mites and anti-mildew additives are Ultra Fresh® additives.
4. Sanitary fabric according to any of the previous claims, characterised in that said solution contains preferably between 34 and 35.9% of said dry resin, preferably
between 64 and 65.9% of said solvent and preferably between 0.1 and 1%, more preferably
between 0.4 and 0.6%, still more preferably equal to 0.5% of said additives in weight.
5. Sanitary fabric according to any of the previous claims, characterised in that said solution contains preferably between 0.1 and 2%, more preferably between 0.3
and 1%, still more preferably equal to 0.5% in catalyst weight of melamine resin.
6. Sanitary fabric according to any of the previous claims, characterised in that said solution contains preferably between 0.01 and 0.5%, more preferably between
0.1 and 0.3%, still more preferably equal to 0.2% in weight of an acid.
7. Sanitary fabric according to any of the previous claims, characterised in that said solution contains preferably between 0.2 and 3%, more preferably between 1 and
2%, still more preferably equal to 1.5% in weight of an isocyanate.
8. Sanitary fabric according to claim 1, characterised in that said layer of micro-sponge fabric (1) is a bedspread micro-sponge.
9. Sanitary fabric according to claim 1, characterised in that said layer of micro-sponge fabric (1) is composed of a 83-denier fireproof fabric
TREVIRA CS®.
10. Sanitary fabric according to claim 9, characterised in that said 83-denier fabric TREVIRA CS® has a decitex measure of 83 g/10000 m.
11. Sanitary fabric according to claim 1, characterised in that a grammage of said micro-sponge fabric (1) is preferably included between 100 and
150 g/m2, more preferably between 125 and 135 g/m2, still more preferably equal to 130 g/m2.
12. Sanitary fabric according to claim 8, characterised in that said bedspred micro-sponge has an overlapping side with said layer (2) spread with
polyurethane having simple Jersey stitch structure.
13. Sanitary fabric according to claim 8, characterised in that said bedspred micro-sponge has an uncovered side made of micro-sponge with slots
preferably equal to 0.7 mm.
14. Sanitary fabric according to claim 1, characterised in that it contains an amount of phtalates that is less than 5% in weight.
15. Process for producing a sanitary product according to the previous claims,
characterised in that it comprises the steps of:
- loading with a plurality of thread reels and supplying with said reels a mono-front
circular machine (20);
- producing a fabric tubular item;
- opening said fabric creating an open and lap-wound fabric;
- cataloguing and dividing in batches said open fabrics;
- supplying a second Rameuse machine with said fabric and heat-settling said fabric;
- performing a first pass in foulard of said fabric in a tank containing a solution
of water and softeners;
- performing a second pass of squashing said fabric on press rolls;
- completely unwinding a selvage of said fabric from said second Rameuse machine;
- spreading vinyl glue on edges of said fabric;
- heat-fixing said fabric through a heat treatment in an oven at temperatures preferably
included between 190°C and 210°C;
- spreading said solution on said transfer fabric on a paper support.
16. Process according to claim 15,
characterised in that said step of spreading said solution comprises the steps of:
- loading said fabric on a third machine with three spreading heads;
- spreading on said fist head a first layer of polyether applied onto said paper support
at a temperature preferably included between 140 and 160 °C, with a tolerance preferably
included between 145 and 155 °C, still more preferably at a temperature that is substantially
equal to 150 °C;
- spreading a second layer of said solution on said second head by applying said second
layer onto said first layer at a temperature preferably included between 140 and 160°C,
with a tolerance preferably included between 145 and 155°C, still more preferably
at a temperature that is substantially equal to 150 °C;
- coupling, on said third head, said fabric from said Jersey side with a polymerized
film added to an adhesive film and stabilise said fabric through an heat treatment
at a temperature preferably included between 140 and 160 °C, with a tolerance preferably
included between 145 and 155 °C, still more preferably at a temperature that is substantially
equal to 150 °C;
- removing said paper support when said solution is in contact with said fabric.
17. Process according to Claim 15 or 16, characterised in that said paper support is made of silicone paper.
18. Use of the sanitary fabric according to one of Claims 1 to 14 to produce bed sheet
for sanitary use, covers for mattresses, covers for pillows, padding and/or clothes
that are fireproof, watertight, breathable, resistant to bacterial and/or chemical
aggressions, or that can be washable and sterilizable at high temperatures.