Technical Field

The present invention relates to a manufactured article in sheet form, particularly intended for use in the manufacture of footwear, clothing items and accessories, upholstery or the like, and related realization procedure.

Background Art

The manufacture and use of cloths, fabrics, hides or other manufactured articles in sheet form are known used in the clothing, accessories and upholstery field. They are used to make footwear, leather goods, handbags, etc., or to upholster padded parts of furniture components, car interiors, motorcycle saddles and the like.

Such manufactured articles are made using synthetic materials, particularly polymers such as e.g. polyurethane, polyesters and PVC.

A typical example of a manufactured article in sheet form is imitation leather intended for various uses, including the production of handbags.

Imitation leather is normally made of polyurethane and can have different types of structure and finish.

Such manufactured article made of polyurethane includes among its particular features that of being lightweight, wear-resistant, water-repellent, easy to use and clean.

Traditional manufactured articles in sheet form, however, have some drawbacks.

Because they are made of polymeric materials, such manufactured articles have very little capability of dissipating heat, causing considerable discomfort to the user due to the increase in temperature perceived, especially in the hottest periods of the year.

In particular, if the manufactured article is used for the production of garments and clothing accessories, the increase in perceived temperature causes an increase in sweating, with consequent considerable discomfort. Such drawback is particularly noticeable in the case where the manufactured article in sheet form is intended for use in the footwear sector.

In fact, the increase in temperature inside the footwear and the incorrect transpiration of the foot produce problems related to hygiene and comfort of the user.

Description of the Invention

The main aim of the present invention is to provide for a manufactured article in sheet form, particularly intended for use in the manufacture of footwear, clothing items and accessories, upholstery or the like, and related realization procedure which allow improving heat dissipation and reducing the temperature perceived by the user.

Another object of the present invention is to provide for a manufactured article in sheet form, particularly intended for use in the manufacture of footwear, clothing items and accessories, upholstery or the like, and related realization procedure which allow obtaining a high level of comfort for the user.

A further object of the present invention is to provide for a manufactured article in sheet form, particularly intended for use in the manufacture of footwear, clothing items and accessories, upholstery or the like, and related realization procedure which allow limiting perspiration due to the contact with the manufactured article itself and improving hygiene, especially when used in the footwear sector.

Another object of the present invention is to provide for a manufactured article in sheet form, particularly intended for use in the manufacture of footwear, clothing items and accessories, upholstery or the like, and related realization procedure which allow overcoming the aforementioned drawbacks of the prior art within the scope of a simple, rational, easy, efficient to use and cost- effective solution.

The aforementioned objects are achieved by the present realization procedure of a manufactured article in sheet form, particularly intended for use in the manufacture of footwear, clothing items and accessories, upholstery or the like, according to claim 1.

The aforementioned objects are also achieved by the present manufactured article in sheet form, particularly intended for use in the manufacture of footwear, clothing items and accessories, upholstery or the like, according to claim 4.

Brief Description of the Drawings

Other characteristics and advantages of the present invention will become more evident from the description of a preferred, but not exclusive embodiment of a manufactured article in sheet form, particularly intended for use in the manufacture of footwear, clothing items and accessories, upholstery or the like, and related realization procedure, illustrated by way of an indicative, but non- limiting example, in the attached drawings in which:

Figure 1 is an axonometric view of the step of mixing graphene with a polymeric material provided for by the procedure according to the invention; Figure 2 is an axonometric view of the step of spreading a layer of primer onto a transfer sheet provided for by the procedure according to the invention;

Figure 3 is a sectional view of the step of drying for a first time the sheet provided for by the procedure according to the invention;

Figure 4 is an axonometric view of the step of spreading a layer of composite material provided for by the procedure according to the invention;

Figure 5 is a sectional view of the step of drying for a second time the sheet provided for by the procedure according to the invention;

Figure 6 is an axonometric view of the step of spreading an adhesive layer provided for by the procedure according to the invention;

Figure 7 is a sectional view of the step of drying for a third time the sheet provided for by the procedure according to the invention;

Figure 8 is an axonometric view of the step of making a first main face of a substrate adhere on the adhesive layer provided for by the procedure according to the invention;

Figure 9 is an axonometric view of the step of removing the transfer sheet 6 provided for by the procedure according to the invention;

Figure 10 is a sectional view of the manufactured article in sheet form according to the invention;

Figure 11 is an axonometric view of the manufactured article in sheet form according to the invention in a mode of use;

Figure 12 is a t/T graph of a SAMPLE 1 and related reference according to the invention;

Figure 13 is a t/T graph of a SAMPLE 2 and related reference according to the invention.

Embodiments of the Invention

With particular reference to Figures 1 to 9, a procedure is illustrated for the realization of a manufactured article in sheet form 1, particularly intended for use in the manufacture of footwear, clothing items and accessories, upholstery or the like.

The procedure for the manufacture of a manufactured article in sheet form 1, particularly intended for use in the manufacture of footwear, clothing items and accessories, upholstery or the like, comprises at least the following steps:

a step I of mixing graphene 2 with at least a polymeric material to obtain a composite material 3; and

a step II of applying the composite material 3 onto a substrate 4 in sheet form.

Graphene is an allotropic form of elemental carbon, consisting of a monoatomic layer of hybridized carbon atoms sp2.

It is therefore a substantially two-dimensional material, inasmuch as it has an extremely large surface area compared to its thickness, which is equal to the thickness of an atom.

Its particular structure makes it an extremely flexible material, resistant from a mechanical point of view but also with high heat conductivity.

The step I of mixing the graphene with the polymeric material permits obtaining a composite material 3, i.e. a polymeric matrix material in which the graphene 2 is dispersed.

The presence of graphene 2 in the composite material 3 changes the properties of the polymeric material, making it more resistant from a mechanical point of view, but above all conductive from a heat point of view.

Preferably, the graphene 2 is mixed with polyurethane; however, alternative solutions cannot be ruled out wherein one or more polymeric materials other than polyurethane are used.

Usefully, the step I of mixing comprises the step of adding at least one antibacterial additive selected from Echinacea extract and Tea Tree extract to the polymeric material and to the graphene, so as to improve the properties of the composite material by counteracting bacterial proliferation.

The step II of applying the composite material 3 onto the substrate 4 comprises at least the following steps:

a step III of spreading one layer of primer 5 onto a transfer sheet 6;

a step IV of drying the transfer sheet 6 for a first time;

- a step V of spreading the composite material 3 onto the layer of primer 5 to form at least one composite layer 7;

a step VI of drying the transfer sheet 6 for a second time;

a step VII of spreading an adhesive layer 8 onto the composite layer 7;

a step VIII of drying the transfer sheet 6 for a third time;

- a step IX of making a first main face 9 of the substrate 4 adhere on the adhesive layer 8; and

a step X of removing the transfer sheet 6.

Usefully, the transfer sheet 6 is composed of a sheet of paper having a predefined texture such as to reproduce the desired surface finish of the manufactured article in sheet form 1.

Advantageously, the step III of spreading the layer of primer 5 is done by spreading the layer of primer itself onto the transfer sheet 6 by means of a blade 11 which slides at a height set by the sheet itself.

The layer of primer 5 gives smoothness and surface resistance to the manufactured article in sheet form 1 and is made at least partly of polyurethane. After each of the steps III, V, VII of spreading, the steps IV, VI, VIII of drying the transfer sheet 6 are performed respectively in order to fix the spread material and optimize the spreading of the subsequent layer.

In particular, at least one of the step IV of drying for a first time, the step IV of drying for a second time and the step VIII of drying for a third time takes place in a kiln under the following operating conditions:

- temperature: 120 ÷ 180 ° C time: 1 ÷ 10 min.

The adhesive layer 8 used in the step VII of spreading is composed of a single- component aromatic adhesive; the use of different types of adhesive materials cannot however be ruled out.

Usefully, the adhesive layer 8 permits gluing the layers 5, 7 to the substrate 4. The step IX of making the first main face 9 of the substrate 4 adhere to the adhesive layer 8 has, therefore, the function of making the layers 5, 7 adhere and fix onto the substrate itself.

Preferably, such substrate 4 is made of coagulated polyurethane; the use of polymeric materials other than coagulated polyurethane cannot however be ruled out.

Subsequently, in step X, the transfer sheet 6 is removed, thus obtaining the manufactured article in sheet form 1.

Advantageously, the manufactured article in sheet form 1 thus obtained comprises:

at least the substrate 4 in sheet form comprising at least the first main face 9 and at least a second main face 10; and

at least the composite material 3 which is spread onto the first main face 9 to form the composite layer 7 and which comprises at least the polymeric material mixed with graphene.

The presence of the composite layer 7 makes the manufactured article in sheet form 1 conductive from the heat point of view.

The substrate 4 is made of breathable polyurethane, i.e. having a micro porous structure which allows for the passage of air through the substrate itself.

Within the scope of this treatise, the term "breathable polyurethane" means a polyurethane having a value of permeability to water vapor above 1 mg/ (cm2 x h) measured according to the provisions of the SATRA TM 47: 1997 standard. Polyurethane is one of the most versatile polymeric materials in existence and allows obtaining products with very different properties and uses.

In particular, polyurethane is a material with high resistance to mechanical stress, chemically inert with respect to very many organic and inorganic substances, resistant to humidity and to high and low temperatures. The graphene 2 in powder form is contained in the composite material 3 in a weight percentage comprised between 0.1% and 10%.

The possibility cannot be ruled out to add the composite material 3 with at least one antibacterial additive selected from Echinacea extract and Tea Tree extract, so as to make the manufactured article in sheet form 1 antibacterial and antimicrobial.

Preferably, the manufactured article in sheet form 1 comprises at least the adhesive layer 8 interposed between the first main face 9 and the composite layer 7, so that the latter perfectly adheres to the substrate 4.

The manufactured article in sheet form 1 also comprises at least the layer of primer 5 arranged on the composite layer 7.

The manufactured article in sheet form 1 can be intended for various uses.

One possibility is to use the manufactured article in sheet form for coating at least one plate-like support 12 shaped to form an insole 13 for footwear.

The use of this insole 13 allows improving the thermal performance of the footwear, limiting the increase in the internal temperature.

Such characteristics also help limit perspiration by the user, with considerable improvement also from the hygienic point of view.

EXAMPLE 1

A SAMPLE 1 of manufactured article in sheet form 1 was made comprising the substrate 4 in breathable polyurethane, the adhesive layer 8, the composite layer 7 and the layer of primer 5.

To make the composite layer 7 the following were used:

- graphene in the form of nanoplates (GNP), i.e. structures made up of a few sheets of carbon atoms stacked on top of each other, in a concentration by weight compared to polyurethane of 2%, in particular GNP by Strem Chemicals; and

- a non-breathable polyurethane, in particular IMAPUR 2400BV by IMA, prepared by dispersion in a solution of dimethylformamide (DMF), with the addition of isocyanates and melamine, with a concentration by weight of polyurethane between 30% and 50%.

The adhesive layer 8 was made by means of a single-component aromatic adhesive of the non-breathable type, which is ICAFLEX ADM383 by ICAP- SIRA.

To make the layer of primer 5, use was made of polyure thane IMAPUR 1500/20 HR by IMA, which is a type of non-breathable polyurethane.

The measurement was taken of the cooling speed of the SAMPLE 1 by means of an infrared camera, following radiation with a halogen lamp for a few minutes, until at least 50°C was reached.

The measurement was also taken under the same conditions on a graphene-free REFERENCE 1.

Figure 12 shows the curves describing the decrease in temperature over time, as a result of radiation, for both the SAMPLE 1 and the REFERENCE 1.

The cooling speed is determined by the initial slope of the cooling curve.

It was noted that the cooling speed was the same for the two samples examined. The maximum temperature (TMAX) recorded is shown on Table 1.

Table 1

It was noted that the TMAX reached by SAMPLE 1 was higher than the TMAX reached by REFERENCE 1.

The higher TMAX is linked to the presence of graphene in the composite material 3, which improves its heat conductivity; however, the use of non-breathable materials means that there are no changes as regards heat dissipation.

EXAMPLE 2

A SAMPLE 2 of manufactured article in sheet form 1 was made comprising the substrate 4 in breathable polyurethane, the adhesive layer 8, the composite layer 7 and the layer of primer 5.

In this case, to make the composite layer 7 the following were used:

- graphene in the form of nanoplates (GNP), in a concentration by weight compared to polyurethane of 2%, in particular GNP by Strem Chemicals; and

- a breathable polyurethane, in particular NORETHANE NPU511 by NOVOTEX, prepared by dispersion in a solution of dimethylformamide (DMF), with the addition of isocyanates and melamine, with a concentration by weight of polyurethane between 30% and 50%.

The adhesive layer 8 was made by means of a single-component breathable adhesive, which is LARITHANE AB7198 by NOVOTEX.

To make the layer of primer 5 a material was used identical to that used to make the composite layer 7, i.e., polyurethane NORETHANE NPU511 by NOVOTEX to which graphene GNP by Strem Chemicals was mixed in a concentration by weight of 2%.

In this case too, a measurement test was performed of the cooling speed of the SAMPLE 2, carried out according to the same specifications shown for the SAMPLE 1 , comparing the results with a REFERENCE 2 comprising the same materials, but free of graphene.

Figure 13 shows the curves that describe the temperature trend over time as a consequence of irradiation, both for the SAMPLE 2 and for the REFERENCE 2.

In this case the cooling speed of the SAMPLE 2 is slightly higher with respect to the REFERENCE 2.

The maximum temperature (TMAX) recorded is shown on Table 2.

Table 2

In this second case, the TMAX reached by SAMPLE 2 was lower than the TMAX reached by REFERENCE 2.

This result is due to the fact that the graphene contained in both the layer of primer 5 and in the composite layer 7 makes it possible to obtain a more uniform distribution of the Ts, with lower maximum temperature.

Furthermore, the use of breathable materials makes it possible to dissipate heat more quickly than in the previous case, increasing the action performed by the graphene.

It has in practice been found that the described invention achieves the intended objects.

In this regard, it is underlined that the special solution of providing a composite layer containing graphene makes it possible to improve heat dissipation.

Furthermore, the special solution of mixing graphene with breathable polyurethane allows reducing the temperature perceived by the user and obtaining a high level of comfort for the user, especially during hot periods. Still furthermore, the use of the manufactured article in sheet form for covering shoe insoles makes it possible to reduce perspiration by the user, with a considerable improvement also from the hygienic point of view.