DESCRIPTION

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Technical field

The present invention relates to a thermal protective garment suitable for use at low temperatures, in particular suitable for constituting an undersuit for underwater diving in cold water.

It is a thermal protective garment capable of increasing the thermal temperature of the human body in situations of exposure to very cold temperatures, as in the case of underwater diving in freezing or low-temperature water, without having to use further combinations with electric heaters or other garment layers.

The thermal protective garment according to the invention can be catalogued as an undersuit which is produced using a particular yam made specifically for this use, combined with a particular interlocking weave obtainable with latest generation machines that enable the production of a seamless wholegarment, in order to reduce thermal dispersion to a minimum.

The present invention is advantageously applied in the sector of garments produced with thermal yarns, in particular in the sector of undersuits in general and undersuits for underwater diving in particular.

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Prior art

It is well known that underwater diving in cold water requires the use of thick drysuits and special devices or inner garments of the undersuit type, capable of insulating the diver from the temperature of deep water or particularly cold water and its deleterious effects on the human body.

In fact, water dissipates human body heat 25 times faster than in air and the heat capacity of water is over 3500 times greater than that of air. The significant difference between heat loss rates at temperatures in air and water creates a distinct difference in the physiological effects associated with the two conditions.

In order to protect divers from cold in the low-temperature water they dive into it is thus necessary to use first of all a drysuit, which fulfils the task of keeping the body dry, and a thermal protection, which is left up to an undersuit, which is made in various ways and internally combined with the diver’s suit so as to maintain body heat as long as possible.

Several solutions have been conceived to provide solutions to problems of insulating and protecting a diver in a drysuit sufficiently against cold when diving in cold water.

One of these solutions is described in patent US5960469 regarding a liquid- insulated garment for cold water diving. It describes an insulating diving suit comprising liquid, which supplements the traditional internal thermal protection of the suit. The diving suit comprises watertight chambers containing a certain amount of insulating fluid which can be heated.

Such a device requires additional equipment the diver must carry during a dive, and which can increase the difficulty of movement due to the encumbrance during the dive. Furthermore, the interspaces with heated liquid can make it more difficult for the diver to get into and out of the drysuit.

According to other solutions, use is made of active heating systems that contain electric resistive elements in the diving suit or systems which provide a flow of hot water to a heat distributing garment worn by the diver.

The use of a suit with hot water entails that the latter is made to circulate inside a special drysuit at about 37°C or pumped in order to surround the diver with a layer of hot water for thermal protection. The supply of hot water provides excellent thermal protection to divers immersed in cold water as long as the water supply continues; however, the suit does not offer real protection for a diver in the event of an emergency when the delivery of hot water is interrupted.

It has been demonstrated that the temperatures of the water in the suit fall to dangerously low levels in a few minutes after the interruption of the hot water supply, so wearing an electrically heated suit is not devoid of danger. An interruption in the supply to the electric suit can quickly expose a diver to temperature conditions that jeopardise his or her survival.

According to further solutions, the traditional undersuits used up to now for diving suits are conceived by producing knitted garments in separate portions that are joined together by means of stitched seams that create body heat-dispersing thermal points, and do not have the possibility of maintaining and increasing body temperature without the use of a battery-powered electric heated vest that is worn.

Therefore, in accordance with the present invention, the need to overcome the deficiencies of the existing underwater diving suits has been addressed by providing an undersuit having features such as to store latent heat while it remains in contact with the body before the dive and which is capable of maintaining it, thus protecting the diver during underwater dives in cold water, as it has an interspace with a high capacity to maintain body heat, placed between the diver’s skin and the diving garment.

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Summary

The present invention aims to provide an undersuit which, because of its specific design, enables the heat of a human body immersed in cold water to be maintained for the longest possible time and is totally devoid of electric resistance heating elements, thus creating a condition capable of eliminating or at least reducing the drawbacks highlighted above.

The invention aims in particular to provide an undersuit for underwater diving in cold water which brings about an immediate effectiveness, due mainly to the absence of external energy sources, with all the advantages deriving therefrom.

These aims are achieved by a thermal protective garment according to the invention, which is capable of increasing the thermal temperature of the human body when it is exposed to very cold temperatures, as in the case of underwater diving in freezing or low-temperature water, without the need to use further combinations with electric heaters or other clothing layers.

The thermal protective garment according to the invention is thus represented by an undersuit that is produced by weaving using a yam specifically made for this use, i.e. one with good properties of maintaining body heat and, combined with a weave obtainable with special machines enabling the production of a seamless wholegarment, in such a way as to reduce heat loss to a minimum.

In particular, the invention is aimed at a garment of the undersuit type, with a high capacity to maintain the thermal energy produced by a user wearing said garment. Specifically, the garment comprises a polyester yarn having a denier value comprised between 120 and 220 g/9000m and treated with an additive based on nanoparticles configured at least to reflect the infrared radiation emitted by the user so as to retain at least part of the amount of thermal energy. In addition, the additive has a dosage comprised between 1 and 20% relative to the yam, whilst the nanoparticles of the additive have a maximum diameter of 500 nm and, moreover, define red and/or orange and/or yellow and/or green and/or blue and/or violet coloured pigments. Finally, the yam is processed so as to produce an interlocking weave of the seamless wholegarment type in order to obtain the garment without stitched seams.

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Brief description of the drawings

Other features and advantages of the invention will become apparent upon the reading of the following description of one embodiment of the invention, provided by way of non-limiting example, with the aid of the figures illustrated in the appended drawings, in which:

- figure 1 represents a graphic representation of the basic settings of the needles in a knitting machine intended to produce the undersuit according to the invention with the “seamless” method;

- figure 2 illustrates a further graphic representation of the needles of a machine intended to produce the same undersuit with the “seamless” method.

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Detailed description of at least one embodiment

With reference to the appended figures, and initially in particular to figure 1 , 10 generally indicates the graphic representation of the basic settings of the needles in a knitting machine intended to produce the undersuit 11 according to the invention with the “seamless” method.

According to a preferred embodiment of the invention, the undersuit according to the invention is produced using a particular polyester-based yam, specially created for this design, which undergoes particular processing to produce an interlocking weave achievable with latest-generation WHO LEGARM ENT SHIMA SEIKI machines, which further enable the production of a whole seamless undersuit.

As regards the polyester-based yam, its characteristic lies essentially in the denier value comprised between 120 and 220 g/9000m and it is treated with a carbon nanoparticle-based additive or other pigments described below, with an additive dosage of 18% and in a range of 1 -20% relative to the yam; this makes it possible to obtain a weave characterised by a capacity of rapid natural body heating, with a thermal insulating technology reaching over +13°C of heating in 5-10 min. and a thermal insulation of over 4.6 Clo, the thermal insulation unit used for clothing.

According to a preferred embodiment of the invention, the denier value of the polyester yarn is comprised between 162 and 165 g/9000m and the additive dosage is equal to about 8-9% relative to the yam.

Furthermore, according to a specific embodiment of the polyester yam, it is of the 2/75/72 DDC-SPX DH INT BB75 STC type, i.e. double twisted.

The additive with which the polyester yam is treated reacts to heat with a chemical reaction that allows body heat to remain stored within the yam, thereby heating it. The principle is to absorb the thermal energy emitted by the human body of the wearer of the garment and thus to react so as to maintain heat also in the case of use in cold environments, thereby obtaining a considerable advantageous performance compared to prior art solutions as regards insulating capacity and the capacity to keep cold outside and to retain the stored heat.

The fabric obtained with said yam treated with the additive offers rapid, high insulating properties of 0.8 to 3.2 Clo, and a rapid body heating effect that can add up to +28°C and more, a rapid increase in local blood circulation, a high deodorant effect, and a capacity to maintain dryness.

In particular, the unit of measurement “Clo” identifies the insulation provided by any layer of air trapped between the skin and clothing and the insulation value of the clothes themselves. A garment having one Clo unit is capable of maintaining a person at rest in comfortable conditions for an indefinite time in an environment at 21 °C with 50% relative humidity and 0.01 m/s of air movement.

In detail, in the textile sector and in the sector of clothing thermal insulation, 1 Clo is equivalent to about 0.155 °K metre ² / Watt.

The additive with which the polyester yam is treated is a coating composition that contains two or more types of red, orange, yellow, green, blue and violet pigments with a particle diameter of 500 nm or less which show a high reflectance of light radiation in the ultraviolet and near-infrared regions, in a proportion such as to produce a low brightness colour, in particular an achromatic black, i.e. an additive mixture with an excellent lifespan and long-term effectiveness in retaining heat.

The additive is obtained from a mixture consisting of several types of pigments selected from red pigments with a particle diameter of 500 nm or less, which show a solar reflectance of 45% or more in the range of 350 to 2,100 nm, calculated from spectral reflectance (RAi).

Use can be made, additionally or alternatively, of orange pigments with a particle diameter of 500 nm or less, which show a solar reflectance of 55% or more, or yellow pigments with a particle diameter of 500 nm or less which show a solar reflectance of 60% or more, or green pigments with a particle diameter of 500 nm or less which show a solar reflectance of 20% or more, or blue pigments with a particle diameter of 500 nm or less which show a solar reflectance of 20% or more, or violet pigments with a particle diameter of 500 nm or less which show a solar reflectance of 35%, said pigments representing from 2 to 60% by weight of the solids of said additive.

The additive can further comprise a low brightness pigment, particularly achromatic black, obtained with an additive mixture of red, orange, yellow, green, blue and purple for use in a coating composition for protecting against solar heat without using black pigments. The pigments for the additive mixture can be selected in consideration of their tone, resistance to atmospheric conditions and colour stability.

A red pigment can be selected from among the following pigments identifiable as Pigment Red (PR) and with the Colour Index Pigment Number (C.l. No.) of the Society of Dyers and Colourists or the colour pigment database called “The Color of Art Pigment Database”: PR3, PR5, PR48, PR58, PR88, PR112, PR122, PR123, PR144, PR149, PR165, PR168, PR170, PR171 , PR175, PR177, PR178, PR179, PR187, PR189, PR190, PR194, PR202, PR207, PR209, PR214, PR216, PR224, PR242, PR253, PR254, PR260 and PR351.

An orange pigment can be selected from among the following pigments identifiable as Pigment Orange (PO) and with the C.l. No. or from the colour pigment database called “The Color of Art Pigment Database”: PO5, PO13, PO16, PO34, PO36, PO38, PO43, PO60, PO62, PO65 and PO69.

A yellow pigment can be selected from among the following pigments identifiable as Pigment Yellow (PY) and with the C.l. No. or from the colour pigment database called “The Color of Art Pigment Database”: PY1 , PY3, PY13, PY14, PY16, PY17, PY24, PY42, PY55, PY73, PY74, PY81 , PY83, PY93, PY94, PY95, PY97, PY98, PY105, PY108, PY109, PY110, PY116, PY117, PY120, PY128, PY129, PY130, PY137, PY138, PY139, PY147, PY151 , PY153, PY154, PY155, PY165, PY173 and PY175.

A green pigment can be selected, for example, from among PG7, PG10 and PG36, where PG stands for Pigment Green and the number for the C. I. No or from the colour pigment database called “The Color of Art Pigment Database”.

A blue pigment can be selected, for example, from among PB15: 1 , PB15:2, PB15: 3, PB15:4, PB15:6, PB16 and PB60, where PB stands for Pigment Blue and the number for the C.l. No or from the colour pigment database called “The Color of Art Pigment Database”.

A violet pigment can be selected, for example, from among PV19, PV23 and PV257 where PV stands for Pigment Violet and the number for the C.l. No or from the colour pigment database called “The Color of Art Pigment Database”.

It is necessary that the aforesaid pigments offering good heat-retaining properties have a particle diameter of 500 nm or less, more particularly of 100 nm or less.

It is further necessary that a pigment with the aforesaid particle diameter is present in an amount of 2 to 60% by weight of the solids of the coating. With less than 2% by weight of the pigment, the colouring becomes insufficient, and a thicker layer is necessary. On the other hand, with over 60% by weight, an excessive amount of pigment in the coating negatively impacts resistance to chalking, which means poor resistance under the different conditions of use.

A coating composition formulated as described above is dissolved prior to use in a water-based solvent.

It is possible to use, according to need, planarization agents, ultraviolet absorbers, viscosity modifiers, hardening catalysts, pigment dispersing agents, pigment sedimentation inhibitors and colour segregation inhibitors.

The seamless weave of the undersuit according to the invention is preferably produced by means of a process with a SHIMA SEIKI MACH 2XS F.15 machine, with machine threading with 10 numbers of yam guides used. The arrangement of the yarn guides is the following:

• yarn guide 1 = 4 plies of 85 dtex yarn for the left wrist;

• yarn guide 2 = 4 plies of 85 dtex yarn for the right wrist; • yarn guide 3 = 4 plies of 85 dtex yarn for the collar;

• yarn guide 11 = 1 separating ply for machine plant;

• yarn guide 7 = 1 separating ply for machine plant;

• yarn guide 4 = 4 plies for the left arm;

• yarn guide 5 = 4 plies for the right leg and arm;

• yarn guide 6 = 4 plies for the torso and left leg;

• yarn guide 8 and 18 = elastic yarn for machine plant + stitching ply for unthreading.

The working steps by means of the above-mentioned yarns guides are the following: a) starting and preparing the machine with the elastic yarn guide 8 for casting on the comb and continuing with the initial separation (yam guides 7 and 11 ); after that the yarn guides 2 and 3 make the edges of the legs for 102 runs in 1x1 tubular; b) the yam guides 6 and 5 begin to work to produce the legs with the weaving process, module of 6 needles x 10 strokes with one feed with a 4-needle process for 4 retained strokes for 1050 runs. This type of manufacturing process makes it possible to create cushions that are designed to obtain a microcirculation of internal body air and do not allow the undersuit to adhere to the skin like a suction cup, which keeps the skin dry and does not create points of moisture; c) the two legs are joined together and the construction of the torso begins with 270 strokes with the same process; d) the yam guides 1 and 2 come in to proceed with the wrists of the sleeves for 102 runs in 1x1 tubular ribbing; e) the process continues with the yam guide 4 for the construction of the left sleeve, while the yam guide 6 simultaneously knits the torso and the yam guide 5 continues with the right sleeve for 776 weaving runs; f) the sleeves are attached to the torso with a series of movements and then the yam guide 6 continues for 348 strokes in order to complete the shoulder and collar part; g) the yam guide 3 comes in to construct the collar in 2x2 ribbing for 40 strokes; h) the process ends with a chain stitch to finish the collar and complete the knit.

At this point our undersuit is perfectly finished with no further stitching and only a zipper will be applied on the front to facilitate wearability. Preferably, the garment is devoid of elastics positioned at the openings thereof, for example the openings situated at the collar, wrists and/or ankles of an undersuit. In such portions of the garment, it is preferable to create a placket capable of guaranteeing excellent tightness thanks also to the polyester yam used.

In accordance with a preferred aspect of the invention deriving from the abovedescribed features, in particular the features related to the mechanical threading steps, the garment can be produced with different degrees of density depending on the number of plies of yarn used to produce the weft and warp. In this manner it is possible to produce garments with different thermal insulation capacities (depending on the end user) and, consequently, a different price. A larger number of plies corresponds to greater thickness and, therefore, to a higher capacity to maintain the thermal energy produced by the user.

Preferably, the garments are entirely produced, in every part thereof, with a yam comprising four plies, which is capable of maintaining a comfortable body temperature also at an ambient temperature of 10 °C (for example, in the case of divers, also in cold water with a temperature as low as 10 °C). The garment has given substantially positive results even at a temperature of 9 °C, whereas for lower temperatures it might be preferable to use a yam that comprises six plies and allows a condition of comfort to be obtained at least down to a temperature of 7°C.

A prototype of the weave of the garment according to the invention which uses such yam has been tested together with a previous garment produced with known techniques in order to assess the thermal insulation, and based on the test it was demonstrated that the yam processed with this type of weave according to the invention reached excellent results from the standpoint of heat retention, confirmed by practical tests performed on divers who engage in cold water diving, and considerable comfort was confirmed, but also and above all an excellent retention of body heat, with an increase of up to about 18°.

Ultimately, the undersuit according to the invention makes it possible to have a single comfortable garment with high heat retention in contact with the skin, and with better wearability and effectiveness, as it makes it possible not to wear suits with an electric battery or extra garment layers.

The invention has been previously described with reference to a preferred embodiment thereof. However, it is clear that the invention is susceptible of numerous variants falling within the scope thereof, in the context of technical equivalence.