Technical field of application

The present invention relates to the sportswear sector, and in particular concerns a knitted fabric for sportswear, particularly suitable for producing jerseys and trousers for tennis players. hereinafter, said knitted fabric will be defined also simply as “fabric”.

In the description below, reference will be made to the percentage values of yarn in the fabric, to be understood in relation to weight.

Background art

Just as for all sports, to play tennis it is necessary to wear specific clothing, produced with high performance materials and a cut that follows movements, both during training and in matches. In fact, this is a very dynamic sport, and the players’ clothing should have very specific features of fit, breathability and strength.

Tennis is played prevalently outdoors, in open-air courts, but also indoors. To meet the needs of the player in any space and atmospheric conditions, tennis clothing must be designed not only to accommodate the athlete’s fit, but also possible variations in temperatures and weather conditions.

Tennis clothing should always be produced with a fabric capable of fully respecting the physiological needs of the player, while remaining comfortable to facilitate movements. The essential technical feature of tennis clothing should be its ability to dissipate heat and manage perspiration optimally.

Most garments currently available on the market are produced with mono knitted fabrics, i.e., produced with only one type of yarn.

Therefore, garments made with 100% cotton, 100% polyester or 100% polyamide (nylon) fabrics, possibly with a minimum amount of elastic yarn (2-10%), are known.

These knitted fabrics have some limits and drawbacks.

Natural fibers, such as cotton, have a high absorption capacity (equal to 1/3 of their raw fiber weight), of perspiration in this specific case, but slow moisture wicking rate and consequently garments remain damp for a long time.

The man-made fiber polyester is completely hydrophobic, i.e., nonabsorbent, but on its own is unable to effectively wick body moisture away. Although polyester fabric is not absorbent, it still gets impregnated with perspiration, which deposits in the interstices of the weave of the fabric, saturating it. This gives a feeling of damp skin, which paradoxically is more intense the tighter the stitches of the fabric are: as polyester is not permeable, it does not allow the perspiration to pass through the fabric and therefore this perspiration remains trapped between the skin and the garment, giving a sort of “cellophane effect”, even if the actual fiber remains substantially dry.

On the contrary, the man-made fiber polyamide is partly hygroscopic (6-9%), with gradual moisture wicking. Therefore, the player perceives a feeling of damp skin, as well as sudden changes in the thermal insulation (poor heat conduction) based on the external weather conditions.

The market also offers knitted fabrics composed of two yarns, which however have limits and drawbacks:

- polyester-polyamide fabrics: in a garment made with a fabric with these features the skin usually only comes into direct contact with the polyester, which with great difficulty attempts to wick body moisture away; therefore, the player perceives a feeling of damp skin and the outside of the garment remains damp for a long time;

- polypropylene-polyamide fabrics: although the polypropylene partly solves wicking away of moisture, the polyamide part still remains damp for a long time.

The document CZ 9 433 U1 discloses a knitted fabric composed of two yarns, comprising a first yarn in polypropylene and a second yarn in polyester. This fabric consists of two layers knitted separately: the first layer is made entirely of polypropylene and is suitable, when in use, to be placed in contact with the skin of a user, while the second layer is made entirely of polyester. The two layers are substantially separate from each other and joined only at some tying points. These tying points create transverse cavities arranged discontinuously between the two layers, through which the perspiration of the user can be wicked from the skin toward the outer layer of the fabric. Adversely, the construction of the fabric with two separate layers makes the fabric heavy, and consequently not suitable for use in sportswear. Moreover, although partially solving the problem of wicking moisture away with the use of polypropylene, using discontinuous tying points between the layers does not allow uniform distribution of dampness, which remains concentrated only in some limited areas, in this way slowing wicking.

Presentation of the invention

The object of the invention is to produce a knitted fabric for sportswear capable of providing the user with maximum comfort, obtained through the ability to dissipate the heat produced by the body in movement and through the ability to manage perspiration, leaving an optimal minimum film of perspiration on the skin of the user and wicking away the excess.

The objects are achieved with a knitted fabric for sportswear comprising a first yarn and a second yarn knitted together, where said first yarn only comprises a polypropylene fiber, characterized in that:

- said second yarn comprises an intimate blend of a man-made fiber of plant origin and a polyester fiber,

- said first and said second yarn are knitted together to form a two- sided fabric, where each side comprises both said yarns, where the first side, destined to come into contact with the skin of a user when in use, comprises a percentage by weight of the first yarn greater than 50%, and the second side comprises a percentage by weight of the second yarn greater than 50%.

According to a first aspect of the invention, said man-made fiber of plant origin is produced from cellulose.

According to a further aspect of the invention:

- said first side comprises 80% by weight of the first yarn and 20% by weight of the second yarn;

- said second side comprises 20% by weight of the first yarn and 80% by weight of the second yarn.

Advantageously, said blend comprises a percentage by weight of man-made fiber of plant origin greater than the percentage of polyester fiber.

In a preferred variant, said blend comprises a percentage by weight of man-made fiber of plant origin of 60% and a percentage of polyester fiber of 40%. The invention has numerous advantages deriving from the combination of fibers chosen, from knitting of the yarns and from the particular two-sided structure of the knitted fabric thus obtained.

The main advantage of the invention is that the first yarn, the one predominant on the inner side, wicks away the excessive perspiration from the skin toward the outer side of the jersey, the one predominantly composed of the second yarn, which instead partly absorbs said perspiration (with the cellulose fiber) and partly continues to facilitate wicking, diffusion and uniform distribution on this side (with the polyester fiber) creating ideal breathability and hence promoting faster wicking and greater comfort.

A further advantage due to the combined and synergic action of the two yarns is that of maintaining the skin damp as long as possible only by a thin hydrolipidic film (which cools the body but without suffocating the pores of the skin), and of expelling and wicking the excess perspiration as quickly as possible: all this promotes optimum comfort in sporting activities that cause heavy perspiring.

The three fibers chosen to produce the two yarns are complementary to one another in features and functions.

The second yarn in particular is formed by the composition of two fibers opposite as regards hygroscopic and hydrophobic properties: the cellulose plant fibers absorb humidity and water vapor, without giving a perception of dampness, while the polyester fibers are water repellent, i.e., the allow water, such as perspiration, to run off in tiny droplets and at the same time allow water vapor to pass from the inside of the knitted fabric, skin side, toward the outside thereof.

The perspiration, wicked by the first polypropylene yarn predominant on the inner side in the direction of the second yarn predominant on the outer side, is channeled in a widespread and uniform manner toward the outer surface of the knitted fabric, while the gaseous moisture, or dampness, is absorbed by the second yarn predominant on the outer side, in particular by its cellulose fibers.

Bacterial proliferation, which causes unpleasant odors, is neutralized by a particular chemical bond intrinsic in the cellulose fiber and by the high resilience of the polypropylene (chemically impenetrable surface).

The blend of fibers chosen reduces possible problems of the formation of loose fibers and their accumulation into small balls (pilling), and the high resistance to dampness of the polypropylene prolongs the useful life of the fabric. Moreover, for an advantage also of aesthetic nature, the creases that can occur on the fabric during use, which already on polyester disappear with vapor, are further relaxed by the high resilience of the polypropylene (relaxation property).

Brief description of the figures These and other advantages will be more apparent in the description of a preferred embodiment of the invention provided below by way of non-limiting example, and with aid of the figures, wherein:

Figs. 1 and 2 represent, respectively in a sectional and in an axonometric view, a knitted fabric for sportswear according to the invention.

Detailed description of a preferred embodiment of the invention

The invention relates to a technical knitted fabric for sportswear, particularly suitable for producing tennis sportswear, and comprises a first yarn 1 and a second yarn 2 knitted together to form a two-sided fabric.

Said first yarn 1 consists of 100% polypropylene fiber and produces, with a percentage by weight greater than 50%, the first side of the knitted fabric, i.e., the side that in use will be in contact with the skin of the user, i.e. the inner side. Polypropylene is a very light man-made technical fiber, even lighter than water (specific weight 0.91). Therefore, it has a coverage greater than other existing fibers with the same thread count.

It is a completely hydrophobic fiber, and therefore as it does not absorb water (degree of absorption equal to 0.05 of its weight), it has a very short drying time. The static charge of the polypropylene fiber, when rubbed, generates a negative triboelectric charge; perspiration, which as well as water also contains mineral salts, and also has a negative charge. Consequently, the polypropylene fiber and the perspiration repel each other.

As perspiration cannot be reabsorbed by the skin, it is expelled through the polypropylene fiber, toward the outer side of the knitted fabric and hence of the garment and toward the other fibers that are part of the weave of the fabric. Due to its low molecular weight, polypropylene has high thermal insulation, and therefore does not easily transfer environmental heat toward the body of the athlete, helping to maintain the body at its natural temperature.

Moreover, polypropylene fiber: - does not absorb molds and microorganisms, and is therefore bacteriostatic, odorless and stainproof;

- is certified as hypoallergenic fiber, and therefore causes no problems in contact with the skin;

- does not crease easily and is therefore easy care; - does not fade, colors always remain solid as pre-dyed in paste form

(i.e. the plastic mass is dyed before extrusion of the yarn);

- has a very high modulus of elasticity and therefore can easily adapt to stretching during use even along different lines, which promotes the duration of the fabric and of the sportswear garment. Said second yarn 2 is composed of a blend comprising 60% by weight of man-made fiber of plant origin, in particular obtained from cellulose, and 40% of polyester fiber, and produces, with a percentage greater than 50%, the second side of the fabric, i.e., the side that in use will be facing outward with respect to the skin of the user.

Excellent results were obtained with the use of a man-made fiber of plant origin produced with cellulose pulp from beech and eucalyptus trees, known commercially with the name Tencel ^® .

The use of 60% Tencel ^® in the second yarn 2 is motivated by the intrinsic features of this fiber of natural origin:

- 100% biological and environmentally friendly, as the wood derives from sustainably managed forests (PEFC environmental certification and FSC international certification);

- it has a structure with nanofibrils: microscopic rods that rapidly regulate both absorption and wicking of moisture;

- the fibrils of which Tencel ^® is composed, particularly smooth and soft, prevent skin irritation, even when the skin is damp;

- it is an excellent heat regulator: it helps to lower the body temperature, by absorbing the moisture produced by the body in movement;

- it inhibits bacterial proliferation and does not allow a film of perspiration to form on the surface of the fabric and hence of the garment;

- it is capable of dissipating electrostatic charges, as it is a static-free fiber and, due to an average internal humidity of 13%, it helps to reduce rubbing between the surfaces of the two yarns. The use of 40% polyester in an intimate blend in the second yarn 2 advantageously makes it possible to:

- reduce the total amount of perspiration retained by the fabric inhibiting excessive hydrophilicity of the Tencel ^® ; - promote the propagation of perspiration toward the second side of the fabric, increasing the wicking surface and hence accelerating the wicking process;

- help to maintain the dimensional stability of garments produced with said fabric, maintaining the correct fit, even when damp. The particular processing of the knitted fabric and the preferred uniform knitting technique of the two yarns, where the two yarns 1 , 3 are knitted directly together and according to which:

- said first side comprises 80% by weight of the first yarn 1 and 20% by weight of the second yarn 2; - said second side comprises 20% by weight of the first yarn 1 and

80% by weight of the second yarn 2, increase and valorize the intrinsic features of the fibers chosen.

Figs. 1 and 2 illustrate this distribution of the yarns 1 and 2.

The construction of a knitted fabric as described above is particularly advantageous through the use of large diameter circular knitting machines with seamless technology produced in an endless tubular fabric.