EP1672117A1

EP1672117A1 - Sanitary fabric and process for producing such fabric

Info

Publication number: EP1672117A1
Application number: EP04425919A
Authority: EP
Inventors: Regaldo Mardo
Original assignee: Reg-Ma Srl
Current assignee: Reg-Ma Srl
Priority date: 2004-12-15
Filing date: 2004-12-15
Publication date: 2006-06-21
Anticipated expiration: 2024-12-15
Also published as: DE602004018955D1; ATE420240T1; EP1672117B1

Abstract

A sanitary fabric is disclosed, that is composed of a layer of micro-sponge fabric (1) and a layer (2) spread with polyurethane, such layer (2) spread with polyurethane being composed of a solution of dry resin, anti-mites additives, anti-mildew additives and solvent; the process for producing a sanitary fabric is also disclosed.

Description

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.
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.

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.

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.
A further object of the present invention is providing a sanitary fabric with fire-proof features.
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.
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.

With reference to the above Figures, a particular embodiment of the present invention is shown and described here.
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.
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".
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.
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.
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.
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.
The layer with a polyurethane coating has been added with additives anti-mite and mould, possibly Ultra Fresh additives mixed in the polyurethane resin.
The fabric according to the present invention is resistant to high temperatures, water-proof and transpirant.
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).
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).
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).
Resistance tests have highlighted the following features.
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).
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).
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).
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).
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).
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.
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.
In the case of a new fabric, the impermeability is guaranteed over the 36 hours with a water column equal to 140 cm.
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.
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.
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.
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.
The fire resistance is tested through the definition of the propagation speed of the flame on horizontal sample prototypes.
Such test has shown that the propagation is lower than 100 mm/min (UNI Regulation 4818, pt 19).
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.
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).
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).
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.
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.
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%
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.
The invention does not contain "phthalic acids" in a quantity greater than 5%.
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.
In order to obtain these two different sides, the machine which produces the fabric has been favourably and purposely modified.
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.

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.
A 0.5% of Ultra Fresh® in weight is preferably added to the solution.
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.

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%.
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%.
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.
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.
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.
The operation and the destination of use of the present invention will now be described.
According to this invention, the fabric can be used as bed sheets for hospital use, un-washable and high temperature sterilizable.
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.
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.

Claims

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.
Sanitary fabric according to claim 1, characterised in that said dry resin is a polyurethane resin of polyether nature.
Sanitary fabric according to claim 1, characterised in that said anti-mites and anti-mildew additives are Ultra Fresh® additives.
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.
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.
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.
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.
Sanitary fabric according to claim 1, characterised in that said layer of micro-sponge fabric (1) is a bedspread micro-sponge.
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®.
Sanitary fabric according to claim 9, characterised in that said 83-denier fabric TREVIRA CS® has a decitex measure of 83 g/10000 m.
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.
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.
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.
Sanitary fabric according to claim 1, characterised in that it contains an amount of phtalates that is less than 5% in weight.
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.
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.
Process according to Claim 15 or 16, characterised in that said paper support is made of silicone paper.
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.