IT202000006826A1 - Composite tape - Google Patents

Description

DESCRIPTION

of the industrial invention entitled:

Composite tape

The present invention relates to a composite tape and in particular a composite tape comprising melted and blown fibers and particulate material, for example absorbent or superabsorbent material.

Composite tapes are known comprising melted and blown fibers, so-called? Meltblown? and spunbond, in which? trapped a particulate material, for example in the form of discrete particles.

The particulate material can? being for example absorbent or superabsorbent polymeric material and examples of composite tapes comprising melted and blown fibers and discrete particles are described and illustrated in documents US6494974, EP0156160.

By absorbent (or superabsorbent) material we mean a material capable of retaining any liquid, or of filtering a fluid (liquid or gas) containing a foreign substance (solid, liquid or gas).

With respect to composite webs comprising melted and blown fibers between which discrete particles of liquid-absorbing material are trapped,? felt the need to improve their skills? of absorption of the liquid at par? of quantity? of discrete particles of absorbent or superabsorbent material present, or to reduce the quantity? of discrete particles of superabsorbent material used in the same way? of absorbed liquid.

In this context, we want to propose a composite tape comprising melted and blown fibers in which discrete particles are trapped, in particular particles of absorbent or superabsorbent material, capable of satisfying the above requirement.

In particular, ? It is an object of the present invention to provide a composite tape comprising melted and blown fibers and discrete particles, for example of absorbent or superabsorbent material, in which the quantity is optimized. of discrete particles dispersed and trapped in the fibers as a function of the performance expected from the composite tape.

Such purpose? achieved by a composite tape comprising the technical characteristics shown in one or more? of the joined claims. The dependent claims correspond to possible different embodiments of the invention.

According to one aspect, the invention relates to a composite tape comprising a mass of melt blown fibers comprising a first melted and blown thermoplastic material and a particulate material dispersed between the fibers and at least partially adhered to them.

According to one aspect of the description, the first thermoplastic material? an elastomer or an elastomeric material.

Basically the composite tape? a tape? meltblown? formed from at least one elastomeric thermoplastic material.

In one embodiment, the composite tape can comprising a hydrophilic additive melted and blown together with said first thermoplastic material to make the composite tape itself hydrophilic.

Especially, an additive that makes the composite tape hydrophilic can? be advantageously used in the case in which the particulate material comprises an absorbent or superabsorbent material.

In such an application, the hydrophilicity of the fibers allows a liquid to be absorbed by the web to effectively reach the absorbent or super absorbent material, for example SAP (Superabsorbent Polymer), dispersed among the fibers.

The elastomer gives the fibers the elasticity? opportune, that is the flexibility, to support the expansion of the SAP during absorption, at the same time keeping it in the fiber matrix and counteracting its dispersion.

Thus, if for example the composite tape according to the description? used to make an absorbent pad of an absorbent product for hygienic use (diaper),? advantageously improved, among other things, the integrity? of the pad itself.

Also, thanks to the properties? of the elastomer, since the fibers can deform more, the SAP pu? expand freely and absorb more? liquid with respect to the case in which it is forced; in this way, at par? of absorbed liquid,? less SAP needed.

According to an aspect of the description, the diameter of the fibers suitably reduced contributes to confer an elasticity? opportune to support the expansion of the SAP.

According to one aspect of the description, a suitable density? of fibers or the number of fibers present in the composite tape gives, to the tape itself, a greater capacity? to support the expansion of SAP; in fact by distributing fewer fibers around the SAP particles, it allows a better expansion.

According to one aspect of the description, the composite web comprises a second thermoplastic material in the fibers.

According to one aspect of the description, the composite tape can? comprising an auxiliary web coupled to said mass of melt blown fibers in which? dispersed the particulate matter.

Advantageously, said auxiliary belt and said mass of melt-blown fibers can be coupled without using glue or adhesive by virtue of this. of the elastomer present in the fibers. In fact, the elastomer, in particular during extrusion and blowing, is sticky and allows the fibers to be joined to the auxiliary belt. In the case of superabsorbent material dispersed in the fibers, the auxiliary tape contributes, in general, to maintaining the integrity? of the padding and of the mass of fibers incorporating the superabsorbent material.

According to one aspect, the present description relates to an absorbent article, for example a diaper, provided with an absorbent padding comprising a length of a composite tape made in accordance with the description.

Further characteristics and advantages of the aforesaid aspects will become clearer from the indicative, and therefore non-limiting, description of a preferred but not exclusive embodiment of a composite tape comprising melted and blown fibers and particulate material.

This description will come? shown below with reference to the accompanying drawings, provided for indicative purposes only and, therefore, not limitative, in which:

Figure 1 illustrates a composite tape comprising melted and blown fibers and a particulate material dispersed therebetween in a schematic side view.

Figure 2 illustrates a microscope image of a composite web comprising melted and blown fibers and a particulate material dispersed therebetween in a first operating condition;

Figure 3 illustrates the composite belt of Figure 1 in a second operating condition; Figure 4 illustrates an absorbent article comprising a composite belt comprising melted and blown fibers and a particulate material dispersed therebetween, in a schematic plan view.

With reference to the attached figures, with the number 1? indicated a composite tape in accordance with the present description.

Tape 1? of the so-called meltblown or spunbond type, that is obtained by extrusion and blowing of thermoplastic material.

The web 1 comprises a mass or bulk or matrix 2 of melt blown fibers 3.

In a preferred embodiment, the fibers 3 have a diameter between 0.1 micron and 30 micron and preferably between 0.5 micron and 10 micron.

In a preferred embodiment, the fibers 3 have a grammage comprised between 0.1 gsm and 300 gsm, preferably between 1 gsm and 20 gsm.

The fibers 3 comprise a first melted and blown thermoplastic material or a first thermoplastic material which is inserted into an extruder for the production of the strip 1.

In a preferred embodiment, the first thermoplastic material, preferably polymeric, for example polypropylene PP or polyethylene PE,? present in the fibers 3 in a percentage comprised between 0% and 99% by weight, preferably in a percentage comprised between 70% and 95% by weight.

Preferably, the first thermoplastic material has a melt flow rate comprised between 1 and 2000, preferably equal to 1200.

In accordance with the present invention, the fibers 3 comprise an elastomer or a substance capable of reducing the elasticity? of the fibers 3 themselves in the sense of decreasing their resistance to deformation due to mechanical stress.

The elastomer can be melted and blown individually (therefore, to constitute entirely the first thermoplastic material), can? be melted and blown together with a first thermoplastic material, or can it? be melted and blown together with a first and a second thermoplastic material (ie the elastomer is inserted into the extruder for the production of the 1 meltblown tape).

In general, the first thermoplastic material and the second thermoplastic material are thermoplastic materials suitable for being melted and blown. Preferably, the first and second thermoplastic materials can be selected, by way of non-exhaustive example, in the following group: Polypropylene and derivatives, Polyethylene and derivatives, Polylactic acid and derivatives, Polyhydroxyalkanoates and derivatives, Cellulose and derivatives, Cellulose acetate and derivatives , Starch and derivatives, Polystyrene and derivatives, Polyesters (for example, Polyethylene terephthalate), Polyurethanes, Polyamides, Polycarbonates, Thermoplastic biopolymers in general, Polyoxymethylene and derivatives, Polysulfone and derivatives, Methacrylates and derivatives. The elastomer, when extruded together with at least the first thermoplastic material, or when it is itself the first thermoplastic material, serves, in particular, to reduce the elasticity? fibers 3 or to make them more flexible and pliable.

In a preferred embodiment, the elastomer? present in said fibers in a percentage comprised between 0% and 99% by weight, preferably in a percentage comprised between 5% and 30% by weight.

In practice, in a preferred embodiment, the fibers 3 can be entirely made, as mentioned, with an elastomeric thermoplastic material, for example Vistamaxx?, So as to be particularly elastic.

In other words, in a preferred embodiment, the elastomer itself constitutes the first thermoplastic material or the mass 2 pu? be made substantially entirely of elastomer.

The belt 1 further comprises a particulate material 4 dispersed between the fibers 3 and at least partially adhered to them.

Preferably, the particulate material? present, in the composite tape 1, with a weight of between 8 and 990 gsm, preferably between 50 and 700 gsm.

In a preferred embodiment, the particulate material 4 comprises an absorbent or superabsorbent material, for example SAP, for example Saviva B3. Advantageously, the elastomer present in the fibers 3 or even constituting them makes them particularly sticky, in particular during meltblowing.

In this way, the particulate material 4 adheres better to them and is retained therefrom. The weight and diameter of the fibers 3 determine, at least in part, the distribution of the same which contributes to the retention of the particulate material.

In a preferred embodiment, the fibers 3 comprise a hydrophilic additive which makes them hydrophilic.

The hydrophilic additive can be added to the extruder or also, for example, sprayed onto the mass 2 downstream of the melt blowing process.

In case the hydrophilic additive is added in the extruder, the hydrophilic additive can? be water-based or non-water based.

The hydrophilic additive? preferably present in the fibers 3 in a percentage comprised between 1% and 10% by weight, even more? preferably in a percentage comprised between 3% and 6% by weight.

The composite tape 1 overall has a weight preferably comprised between 50 and 1500 gsm.

In an embodiment example, the fibers 3 comprise the polymeric material, the hydrophilic additive and the elastomer and the particulate material comprises absorbent or super absorbent material, the composite tape 1 defines a meltblown absorbent composite tape, for example illustrated in Figures 2 and 3 respectively in a dry condition and in a wet condition or after having absorbed a liquid. A composite tape 1 at least so? composed can? for example, it can be used for the production of absorbent paddings intended for sanitary absorbent articles, or also in food or medical applications.

Advantageously, as mentioned, the fibers 3, in another example, can be made by meltblowing only elastomer.

The elastomer present in the fibers 3, therefore their elasticity, the weight of the same and their diameter contribute to the retention of the absorbent material during its growth, optimizing the so-called Wet Integrity which is much greater than 100 compared to for example, to a value between 10 and 80 for a traditional filling with cellulose.

Elasticity reduced and / or diameter of the fibers and / or density? of the fibers help to maximize the percentage of active SAP, reduce its constriction, leave it free to expand without dispersing during the absorption of the liquid.

How will it be? clarified below, the reduced constraint of the SAP? was confirmed by the Applicant through the measurement of the so-called Free absorption and the Centrifugal Retention Capacity (CRC), which are greater than the known solutions, thus indicating a higher percentage use of the SAP.

Advantageously,? therefore improved the capacity? absorbent of the composite tape 1 compared to another traditional absorbent tape at the same level? of quantity? of absorbent material.

The dispersion of the SAP is also very contained, that is,? much improved the so-called Dry integrity, which comes to be less than 1%.

In practice, even with respect to known solutions,? very contained, in a single product, the dispersion of SAP (Dry integrity), the capacity? of use of SAP and Wet integrity. The additive to make the tape hydrophilic can also be sprayed onto the meltblown tape instead of extruded. If the particulate material is superabsorbent, such as SAP, the additive must be non-water based in order not to interact with the superabsorbent material itself.

According to what is illustrated in figure 1 in broken line, in a preferred embodiment, the composite tape 1 can? comprise at least one auxiliary belt 5 and / or 6 coupled to the mass 2 of melt blown fibers in which? dispersed particulate matter 4.

In an embodiment in which the composite tape 1 comprises both auxiliary tapes 5 and 6, the same can form a so-called? Core cover? in particular in the case in which the composite tape 1 is of the absorbent type preferably as previously described.

In this case, the belts 5 and 6 contribute to the retention of the particulate material 4 and contribute to the strength of the composite belt 1.

Preferably, the auxiliary tape 5 and / or 6 comprises a tape 7 of non-woven fabric, for example of the meltblown or spundbond type, said tape 7 of non-woven fabric preferably having a weight of between 1 gsm and 20 gsm.

In one embodiment, the composite tape 1 comprises at least one auxiliary tape 5 or 6 which comprises a tape 8 of non-woven fabric, for example of the ADL (Acquisition Distribution Layer) or high loft type.

Preferably, the web 8 of non-woven fabric has a grammage comprised between 10 gsm and 300 gsm and can? serve to retain the SAP, increase the robustness and softness? of the composite tape 1, distribute a liquid to be absorbed.

Advantageously, in one embodiment, the auxiliary tape 5 and / or 6 or said non-woven fabric tapes 7, 8 and the mass 2 of fibers 3 are coupled without adhesive.

The elastomer present in the fibers 3 can? in particular to allow the mass 2 to be joined to the auxiliary belt 5 and / or 6.

Preferably, in this case, the fibers 3, on the occasion of blowing and melting, are directly deposited on an auxiliary belt 5 or 6 which defines a support layer which acts, for example, as a facing layer or acquisition layer in an absorbent padding. comprising the composite tape 1.

In one embodiment, the auxiliary web 5 and / or 6 comprises cellulose.

Below are reported 3 examples of composite tape in accordance with the present description, preferably intended for the production of absorbent cores or paddings.

For each example, the corresponding characteristics and services of interest identified by the Applicant are summarized.

The so-called? Usage of SAP? ? been estimated as the ratio, expressed as a percentage, between the Centrifugal Retention Capacity (CRC) of the composite tape and the CRC of the pure SAP and / or the ratio, expressed as a percentage, between the Free absorption obtained from the composite tape and the Free absorption obtained from the Pure SAP.

The Centrifugal Retention Capacity? measured according to the Edana NWSP 2410R2 standard method and the Free absorption according to the Edana NWSP 2400R2 standard method; in the following tables? reported the Usage of SAP? calculated as tape CRC / pure SAP CRC.

The? Tensile strength? ? was measured with the standard method Edana 110.4.R0.

The? Wet integrity? ? was tested, with an internal method, using a Philip Hardy machine, well known in the industry, since there is no standardized laboratory test method to qualify the integrity? of an absorbent core.

In the present case, each sample? weighed, 50 ml of a sodium chloride NaCl solution were poured onto the sample and waited 15 minutes; the sample ? been hung up in the machine then? The onset of breaks in the absorbent structure was observed and when they started.

The? Dry integrity? ? it has also been tested with a method of the Applicant and yes? measured the SAP loss in the dry product.

? has been cut a sample or piece from the composite tape 1 and? been weighed. The same champion? been shaken three times and? was the quantity measured? of SAP dropped and the so-called SAP lost? was calculated as the ratio between the dropped SAP and the total weight of the sample.

Advantageously, the composite tape in accordance with the present description has obtained excellent results both when dry and when wet as regards its integrity.

With reference to Figure 4, with reference 100? indicated an absorbent article, for example a diaper, in accordance with the present description and described limitedly to the parts necessary for understanding the present solution.

The absorbent article 100 includes an absorbent portion or pad 101 and a frame 102 on which or in which? positioned the absorbent pad 101.

The padding 101 comprises a length 103 of a composite tape 1 as previously described.

In particular, in section 103? present at least one elastomer in the mass of fibers and some superabsorbent material as particulate material dispersed in the fibers.

Claims (17)

CLAIMS 1. Composite tape comprising: - a mass (2) of melt blown fibers (3) comprising at least one first melted and blown thermoplastic material; - a particulate material (4) dispersed between the fibers and at least partially adhered to them, said tape being characterized in that said thermoplastic material? an elastomer. 2. Composite tape according to claim 1 wherein said elastomer? present in said fibers in a percentage comprised between 0% and 99% by weight, preferably in a percentage comprised between 5% and 30% by weight. 3. Composite tape according to claim 1 or 2 wherein said fibers comprise a hydrophilic additive melted and blown together with said first thermoplastic material. 4. A composite tape according to claim 3 wherein said hydrophilic additive? present in a percentage comprised between 1% and 10% by weight, preferably in a percentage comprised between 3% and 6% by weight. 5. Composite tape according to any one of the preceding claims wherein said particulate material? present with a grammage between 8 and 990 gsm, preferably between 50 and 700 gsm. 6. Composite tape according to any one of the preceding claims, wherein said particulate material comprises an absorbent or superabsorbent material, for example SAP. 7. Composite tape according to any one of the preceding claims comprising a second thermoplastic material present in said fibers in a percentage comprised between 0% and 99% by weight, preferably in a percentage comprised between 70% and 95% by weight. 8. Composite tape according to claim 7 wherein said second thermoplastic material has a melt flow rate comprised between 1 and 2000, preferably has a melt flow rate equal to 1200. 9. Composite tape according to any one of the preceding claims, wherein said first thermoplastic material has a melt flow rate between 1 and 2000, preferably has a melt flow rate equal to 1200. 10. Composite tape according to any one of the preceding claims, wherein said fibers have a diameter between 0.1 micron and 30 micron and preferably between 0.5 micron and 10 micron. 11. Composite tape according to any one of the preceding claims, in which said fibers have a grammage comprised between 0.1 gsm and 300 gsm, preferably between 1 gsm and 20 gsm. Composite tape according to any one of the preceding claims having a weight of between 50 and 1500 gsm. Composite tape according to any one of the preceding claims comprising at least one auxiliary tape (5, 6) coupled to said mass (2) of melt blown fibers (3) in which? dispersed the particulate material (4). Composite tape according to claim 13, wherein said auxiliary tape (5, 6) comprises a first tape (7) of non-woven fabric, for example of the meltblown or spundbond type, said first tape of non-woven fabric preferably having a weight comprised between 1 gsm and 20 gsm. Composite tape according to claim 13 or 14 wherein said auxiliary tape (5, 6) comprises a second tape (8) of non-woven fabric, for example of the air through bonded, ADL, high loft type, said second tape (8 ) of non-woven fabric preferably having a grammage between 10 gsm and 300 gsm. Composite web according to any one of claims 13 to 15 wherein said auxiliary web (5, 6) and / or said first web (7) of non-woven fabric and / or said second web (8) of non-woven fabric and said mass (2) of melt blown fibers (3) are coupled without adhesive. Absorbent article comprising a length (103) of a composite web according to any one of the preceding claims.