Fabric for Wetsuit and Wetsuit Employing Said Fabric

Info

Publication number: 20200146369
Type: Application
Filed: Dec 23, 2019
Publication Date: May 14, 2020
Applicants: (Kobe-shi), NANKAIGOSEN CO., LTD. (Wakayama-shi)
Inventors: Ietoshi Ueda (Kobe-shi), Norio Nakashima (Wakayama-shi)
Application Number: 16/725,109

Abstract

A fabric for a wetsuit wherein weft knit textile cloth comprising bare jersey knit fabric at which polypropylene multifilament yarn and elastic yarn have been knit in plating fashion while said elastic yarn was stretched to an elongation of 1.5 times to 2.0 times, exclusive of 2.0 times, is laminated to either or both faces of a sponge sheet made of chloroprene foam rubber. Furthermore, the elastic yarn in this fabric is thermally fusible polyurethane elastic fiber, and the elastic yarns in the knit textile are thermally fused to each other. Moreover, the elastic yarns are thermally fused to each other by heat-setting at 100° C. to 140° C.

Description

Description

TECHNICAL FIELD

This invention relates to a wetsuit that is worn when surfing or diving or engaging in water sports or other aquatic or underwater activities.

BACKGROUND ART

While wetsuits may depending on the application and period in question include those which are of the two-piece variety, those which are of the full-suit variety in which the top and the bottom are joined together in integral fashion, and so forth, wetsuits in all cases are heat-retaining suits that are worn when engaged in aquatic activities, the structure of which is such as to allow water to enter a gap that is present at the interior of the suit between the suit and the body. When a suit of the appropriate size is worn, because the small amount of water that enters the gap is warmed by the heat of the body to form a thin layer, this makes it possible to provide heat-retaining effect.

Known as such wetsuits are those which employ synthetic chloroprene rubber that has been foamed in sponge-like fashion so as to have closed cells. For example, a double-skinned wetsuit in which synthetic chloroprene rubber skin surfaces are exposed at the outer surface and inner surface thereof has advantages which include the fact that it is easily made to have heat-retaining characteristics by virtue of the thermally insulating properties afforded by a thickness of on the order of 3 mm to 7 mm and the closed cells at the rubber interior, as well as the fact that it is quick-drying and the fact that it is stretchable. This has had problems which include the fact that first and foremost it cannot be described as being easy to put on or take off due to its poor lubricity and high friction, and there is also the fact that it is vulnerable to concentration of stress due to sharp objects, one example of which is that it tends to tear when scratched by a fingernail or the like, and it also has issues with respect to endurance.

Wetsuits in which a material made of Nylon is laminated to one or both of the outer surface and inner surface of a foam sponge sheet made of chloroprene rubber therefore made their appearance in the 1960s. Wetsuits in which such a material made of Nylon is laminated thereto are less easily damaged and have better endurance than those in which the foam rubber sheet is exposed. Because Nylon fibers are of high endurance, wetsuits in which a material made of Nylon is laminated to the surface layer(s) thereof continue even today to be the favored approach and enjoy widespread use.

Furthermore, a wetsuit comprising a rubber layer serving as outer layer; a layer of polyester, Nylon, or other such chemical fibers serving as middle layer; and a fluororesin fiber layer serving as inner layer has been proposed (see, for example, Patent Reference No. 1).

While this was proposed as an inner layer suited to improvement of the situation that exists when the wetsuit is worn by improving the lubricity of the inner layer which is in intimate contact with the body when putting it on and taking it off, inasmuch as a water-absorbing Nylon layer is present as a base layer beneath the surface layer(s), once moisture penetrates as far as the Nylon layer at the interior the situation will be as it was before in that it will tend not to dry easily, and since attempts to prevent it from becoming wet in the first place have not been successful, and since it is unclear whether the fluororesin fiber layer might like the Nylon layer also be affected such that the stretchability or the like thereof becomes unattainable, this has been inadequate and has been beset with practical problems as had previously been the case.

Another proposal that has been made is a sheeting and wetsuit material having a constitution such that a Nylon woven fabric into which a Nylon yarn has been woven is provided at the face at one side of a polyester woven fabric into which hollow polyester yarn has been woven with gaps therebetween, neoprene or other such foam rubber of high thermal insulation and water resistance being provided at the back side of this Nylon woven fabric as a result of having been mutually connected by means of a connecting material, e.g., a woven fabric/rubber connecting layer employing adhesive, a material capable of repeated lamination, or the like (see, for example, Patent Reference No. 2).

While this proposal employs hollow polyester yarn at the surface of the inner layer so as to improve the feel on the skin of the surface which is in contact with the skin, as this is primarily used to convert materials so that they might be used as hospital sheets or the like, it is unclear what specific characteristics it might have were it to be employed as a wetsuit. In addition, as the purpose of the polyester surface layer is the feel on the skin, and because this is predicated on there being many gaps and that these be in communication with the Nylon layer, it will be the case that the Nylon woven fabric will become wet. Furthermore, because this proposal is in combination with Nylon woven fabric, as it lacks stretchability, its practicality as a wetsuit cannot be said to be adequate.

PRIOR ART REFERENCES Patent References

Patent Reference No. 1: Japanese Patent Application Publication Kokai No. 2000-273707 Patent Reference No. 2: Japanese Patent Application Publication Kokai No. 2015-188745

SUMMARY OF INVENTION Problem to be Solved by Invention

Wetsuits made by cutting and sewing fabric in which a material made of Nylon has been laminated to one or both faces of a foam sponge sheet made of chloroprene rubber are currently the favored approach. However, because wetsuits in which a material made of Nylon is laminated to the outer layer or the inner layer are such that the Nylon yarn fibers are themselves hygroscopic, the fact that they absorb moisture causes the surface(s) thereof to become wet and heavy, and to not dry easily.

When engaged in surfing or other such water sports, one might for example put on the wetsuit and take it off any number of times during the course of the day. This being so, although the damp wetsuit is hung out to dry and so forth each time that this is done, because Nylon yarn is hygroscopic, drying tends to take a long time. This being the case, the wetsuit which clings closely is made to cling all more closely when wet, in which state it is no easy task to stretch it and pull on it and otherwise struggle with it so that it might be worn again. It is therefore desired that it either have good stretchability and be not easily wet, or that if it becomes wet that it should be able to dry easily.

Moreover, as a result of repeated use while still wet and in a half-dried state, because saprophytic organisms tend to proliferate in environments that are damp for long periods of time, not only can this cause occurrence of an unpleasant smell during use, but it also cannot be described as being hygienic. Furthermore, when hanging the wetsuit out to dry outdoors after it has been taken off, where the suit is turned inside out so that the inside can dry out first, because this means that drying of the outer Nylon layer must wait its turn, this tends to cause drying time to increase even further.

Furthermore, because wetsuits are envisioned as being used not only in fresh water but in seawater as well, this means that a wetsuit might be immersed in salt water for 4 to 5 hours, which constitutes a considerable usage load on the fabric. Where a material made of Nylon is laminated thereto, it is therefore sometimes the case that a coating is applied to the surface of the Nylon layer so as to impart it with water repellant properties. But as a result of being exposed to seawater for long periods, the abrasion that occurs with use, and so forth, even where the Nylon layer has been imparted with a coating, the water repellant properties thereof easily become diminished. For example, a wetsuit used for surfing might even when used frequently be repeatedly worn during a period that is on the order of 3 months. However, the water repellant properties of the Nylon layer will progressively become diminished during that period, the state of the Nylon layer becoming such that it no longer repels water but immediately becomes wet.

Furthermore, where fibers of low endurance are employed at the surfacemost face of the outer layer, such as where a coating cannot be maintained, because these become abraded and damaged, it has been necessary to additionally employ Nylon at the inside of the outer layer, but this will not make it possible to prevent it from getting wet. Furthermore, with respect to materials such as those which are napped to produce a better feel against the skin, these are not suited to employment at the outer layer but are strictly limited to being intended for the inner layer, and it is usually the case that that which is intended for the inner layer does not lend itself to employment at the outer layer.

Now, upon being worn continuously while still wet, because this will cause the wetsuit to grow cool due to the heat of vaporization that escapes via the fabric surface, the body temperature of the wearer will also be lost, which will tend to cause the body to become cold. In particular, in situations such as during surfing when the upper body is above the water surface while waiting for a wave, if drying of the outer layer surface Nylon of the wetsuit is slow and it continues to be wet for an extended period of time, because there will also be an ocean breeze that is blowing, the body will tend to become cold. There is a risk that the effect of such cold on performance will not be small. Since the intention in wearing the wetsuit was to retain heat, a situation in which the fact that it has become wet causes the body to grow cool would not be desirable.

Moreover, where the wetsuit is worn while the outer layer surface is still wet, when the hands or upper body are made to swing about during surfing, as the seawater on the outer surface of the wet wetsuit is scattered about in the form of spray and strikes the face and so forth, there are situations in which this can be a hindrance during a sports competition or the like. Thus, when engaged in surfing or other such water sports, it is desired that the outer layer surface of the wetsuit also be such that it dries quickly.

Furthermore, because hygroscopicity of Nylon fiber is on the order of 8% to 9% of the dry weight thereof, where a wetsuit has absorbed seawater, as the weight of the suit itself increases and so forth, there is a tendency for it to sink. Because it absorbs water and gets heavy, during a sports competition such as surfing or the like in which the arms and so forth are vigorously swung about and the posture is changed, the unwanted additional load that would accompany the increase in weight would be undesirable.

Of course, that jerseys made of Nylon currently remain the favored approach is due not only to the endurance and strength of Nylon fibers but is also due at the same time to the fact that it is highly stretchable laterally and longitudinally, and easier to wear than synthetic chloroprene rubber alone. One might therefore consider whether it might be possible to select a fiber to use in place of Nylon that would be either nonhygroscopic or less hygroscopic, but unless such a substitute material were able to provide at least the same or better stretchability it could not as a practical matter be considered adequate for use as a wetsuit fabric. This is true not only because the wetsuit must be put on and taken off but also because, since surfing and the like are accompanied by large movements and changes in posture, stretchability such as will permit ease of movement is desired.

But where Nylon material is simply replaced by nonhygroscopic polypropylene yarn, because the elongation thereof will in general be worse than that of Nylon, it will be impossible as a result of mere substitution of materials to attain stretchability or achieve practicality. Furthermore, because the heat resistance of polypropylene yarn is inferior to that of Nylon yarn, there is also the aspect that treatments in which application of heat is employed would be problematic. For example, ingenuity would be required before one could achieve form stability or dimensional stability through use of heat-set treatment, or in fact to even achieve stretchability for that matter. Unless one were therefore able to discover a structure or the like such as might permit achievement of stretchability while taking into account the low heat resistance, it will not be possible to achieve practicality.

A problem to be solved by the present invention is therefore to provide a wetsuit in which a material is laminated that might serve as substitute for the Nylon material used in wetsuits employing fabric in the form of sponge sheeting made of chloroprene foam rubber at which Nylon material is laminated to the outer surface which is currently the favored approach, and to provide a fabric for a wetsuit and a wetsuit employing this fabric that, while being furnished with stretchability on the same order as that obtained with lamination of Nylon material, have superior thermal retention properties, are quick-drying and have good water repellant properties, and do not foster growth of bacteria.

It is also to provide a wetsuit fabric in which a material that has good drying characteristics and favorable stretchability is also laminated to outer layer face(s) at outer layer(s) where possession of endurance is also necessary.

It is also to provide a material which is such that the Nylon substitute material is favorably laminated at a stage prior to when lamination to the sponge sheeting made of chloroprene foam rubber is carried out. That is, because occurrence of wrinkles or shrinkage in the fabric prior to lamination such as would reduce the width of the finished bolt of fabric would make proper lamination impossible, it is to provide a wetsuit and a wetsuit fabric in which lamination to sponge sheeting made of foam rubber is carried out through use of a substitute material that is suitable for lamination.

Means for Solving Problem

Now, based on the fact that polypropylene fiber is almost completely nonhygroscopic, the present inventor(s) looked into whether this might be employed as a substitute material for the Nylon material. Certainly if polypropylene fiber were used, because it is nonhygroscopic there would be no change in strength even if it were to become wet. However, it was understood that there would be problems in that with polypropylene fiber alone it would be impossible to obtain adequate stretchability, and whereas with Nylon the melting point would be 210° C. or higher and the softening point would be 180° C. or higher, because polypropylene has low heat resistance, the softening point thereof being on the order of 140° C. to 160° C. and the melting point thereof being on the order of 165° C. to 175° C., carrying out heat-setting and so forth therewith would be difficult, and as it would tend to form wrinkles if an attempt were made to fabricate a material therefrom that was to be imparted with stretchability, it would be less suitable than Nylon for lamination.

Therefore, as a result of further intensive study by the inventor(s), knit fabric (hereinafter also referred to as “bare jersey knit fabric”) comprising weft knit textile (including circular knit) at which polypropylene multifilament yarn and spandex or other such stretchable elastic yarn are knit in plating fashion is made to serve as Nylon substitute material, being laminated to a sponge sheet made of chloroprene foam rubber to obtain a wetsuit fabric, and a wetsuit employing this fabric was invented.

That is, a first means in accordance with the present invention for solving the foregoing problems is a fabric for a wetsuit wherein weft knit textile cloth at which polypropylene multifilament yarn and elastic yarn are knit in plating fashion is laminated to either or both faces of a sponge sheet made of chloroprene foam rubber.

A second means is a fabric for a wetsuit wherein weft knit textile cloth in which polypropylene multifilament yarn and elastic yarn are knit in plating fashion is laminated to at least an outer layer face of a sponge sheet made of chloroprene foam rubber.

A third means is the fabric for a wetsuit according to the first or second means characterized in that the elastic yarn is thermally fusible polyurethane elastic fiber, and the elastic yarns in the weft knit textile are thermally fused to each other.

A fourth means is the fabric for a wetsuit according to any one among the first through third means characterized in that the elastic yarns are in a state of having been thermally fused to each other by heat-setting at 100° C. to 140° C. It is preferred that heat-set temperature be 100° C. to 130° C., and more preferred that this be 105° C. to 125° C.

A fifth means is the fabric for a wetsuit according to any one among the first through fourth means characterized in that the knitting in plating fashion was carried out while the elastic yarn was stretched to an elongation of 1.5 times to 2.3 times. It is still more preferred that the knitting in plating fashion be carried out while this is stretched to an elongation of 1.5 times to 2.0 times.

A sixth means is the fabric for a wetsuit according to any one among the first through fifth means characterized in that the polypropylene multifilament yarn comprises not greater than 30 filaments, thickness thereof being such as to correspond to 20 decitex to 56 decitex.

A seventh means is the fabric for a wetsuit according to any one among the first through sixth means characterized in that the polypropylene multifilament yarn is such that thickness thereof corresponds to 20 decitex to 56 decitex, and thickness per filament therein corresponds to not less than 1 decitex.

An eighth means is a wetsuit employing the fabric for a wetsuit according to any one among the first through seventh means.

BENEFIT OF INVENTION

The fabric for a wetsuit in accordance with the present invention is such that, because it makes it possible to obtain an outer layer portion that is nonhygroscopic as a result of employment of polypropylene multifilament yarn, it has good water repellant properties and sheds water well, for which reason it is quick-drying. It therefore suppresses growth of bacteria and is hygienic. Furthermore, because knitting in plated fashion with elastic yarn makes it possible for stretchability to be achieved, achievement of stretchability on the same order as that obtained with lamination of Nylon material is made possible.

Furthermore, because the fact that the number of filaments is kept to a low number makes it possible to suppress occurrence of the capillary effect between filaments, it is possible to suppress the amount of water retained in ways other than by hygroscopicity, making fast drying possible.

Furthermore, because the polypropylene multifilament yarn that is arranged at the outer layer has high endurance, it does break up easily as would be the case with sponge sheeting made of foam rubber but is furnished with adequate endurance.

Furthermore, inasmuch as the thermally fusible polyurethane elastic fibers are thermally fused to each other, there being no occurrence of excessive shrinkage of the elastic yarn that is knit in plated fashion while in an elongated state, and dimensional stability of the knit textile prior to lamination being good, because wrinkles do not form, it is capable of being suitably used for lamination. Furthermore, thermal fusion causes it to be less likely to fray and makes it less susceptible to damage.

By causing heat-set temperature to be low, because alteration of the polypropylene multifilament yarn by heat is suppressed, there being no impairment of the texture of the fabric, and there being no formation of wrinkles, dimensional stability is good, and it is possible for this to be satisfactorily laminated to sponge sheeting made of foam rubber.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 (a) is a sectional view of a working example of the present invention in which bare jersey knit has been arranged at both faces; (b) is a sectional view of a working example of the present invention in which bare jersey knit has been arranged at the outer layer face.

FIG. 2 Schematic diagram showing the situation that exists at the knit pattern in a bare jersey knit fabric at which plating was carried out.

EMBODIMENTS FOR CARRYING OUT INVENTION

Below, embodiments of the present invention are described with reference as appropriate to tables and drawings.

When closed-cell sponge-like foam sheeting comprising synthetic chloroprene rubber is used as a fabric for wetsuits, it preferred that it have high elongation, tensile strength, and tear strength, and that it not absorb water. For example, a representative example of a blend thereof might be one in which, in terms of mass %, chloroprene rubber (CR) is 45%, carbon black is 10%, filler is 10%, foaming agent is 10%, plasticizer is 15%, and there are small amounts of vulcanization accelerator, crosslinking agent, and so forth blended therein. Such materials are made to pass sequentially through operations that include kneading, extrusion molding, primary vulcanization, and secondary vulcanization, as well as slicing as necessary, to obtain sponge sheeting made of foam rubber.

In addition, adhesive may further be applied to one or both faces, jersey material may then be placed on such face(s), this being compression-bonded and laminated thereto by means of an upper roller or a set of upper and lower rollers to obtain suit material, and this then being cut and sewn into the desired shape to obtain a wetsuit fabric.

At FIG. 1, (a) is a sectional view showing the situation that exists when sponge sheeting (2) made of chloroprene foam rubber is arranged centrally, and bare jersey knit fabric (3) comprising polypropylene multifilament yarn and elastic yarn is respectively laminated to a wetsuit outer layer face (4) and a wetsuit inner layer face (5). At FIG. 1, (b) is a sectional view showing the situation that exists when bare jersey knit fabric (3) comprising polypropylene multifilament yarn and elastic yarn is laminated to outer layer face (4) at one side of sponge sheeting (2) made of chloroprene foam rubber.

With a density of 0.91 g/cm³, polypropylene is the lightest of the synthetic fibers, being a fiber that floats in water; and it is also highly wear-resistant. Because it is also nonhygroscopic, it is to be expected that when employed as the outer layer of a wetsuit it will dry quickly.

Where cloth is obtained through use of only polypropylene multifilament fibers and this is laminated to foam rubber sheeting, because it will of course be the case that the stretchability of this will be inadequate, use of this without modification as cloth will make it impossible to achieve adequate elongation of the sort that exists with Nylon materials such as will allow it to be worn while it is stretched.

In accordance with the present invention, so as to employ polypropylene and yet also ensure stretchability, knitting is therefore carried out with plating of elastic yarn and polypropylene multifilament yarn. That is, combination of polypropylene with an elastic yarn such as spandex results in a fabric that is both quick-drying and stretchable, with an elongation similar to that of Nylon.

As shown in FIG. 2, plating, also referred to as plated knitting, is a way of knitting in which two yarns are simultaneously knit in tandem such that one is in front and the other is behind. As shown in FIG. 2, polypropylene multifilament fiber (6) and elastic yarn (7) comprising thermally fusible polyurethane elastic fiber are knit together such that the two overlap after the fashion of plain knit. Hereinafter, knit fabric in which there is plating with elastic yarn is also referred to as bare jersey knit fabric.

Note that if the elastic knitting yarn is such that, at the back, polypropylene multifilament fiber is arranged in front (at the stitch), then because polypropylene fiber which has good endurance will be exposed at the outer surface, the elastic yarn will be less likely to break.

As polypropylene multifilament yarn, 33-decitex 24-filament twisted yarn or the like is, for example, preferred. Where this is on the order of 20 decitex to 56 decitex, because the multifilament yarn will not be too thick, by appropriately selecting an elastic yarn comprising thermally fusible polyurethane elastic fiber that is on the same order as this, i.e., 33 decitex or the like, because when plating is carried out to make these into a bare jersey knit fabric it will also be possible to use heat-setting to cause the elastic yarns to thermally fuse with each other, this is preferred. The polypropylene multifilament yarn is such that depending on the manner in which it is caused to be combined with the elastic yarn, it will be possible to achieve the desired stretchability. In addition, where the number of filaments is not greater than 30, because there will be a small number of filaments, there will be less tendency for the capillary effect to occur between filaments. Because it will make it possible to suppress the amount of water retained between filaments, it is preferred that the number of filaments not be made too large.

Thus, the multifilament yarn that is 20 decitex to 56 decitex, i.e., 18 denier to 50 denier, inasmuch as it is polypropylene fiber, will be such that there will be no absorption of water by the filament fibers themselves. Of course, because it is multifilament, there will be retention of water in the gaps between filaments due to the capillary effect and so forth. It is therefore effective to also reduce the number of filaments. Furthermore, if filament thickness is increased, because what would otherwise be fine gaps are made large, this reduces the capillary force and also reduces surface area, permitting decrease in the amount of water adhering thereto.

Thickness is therefore additionally made such that this is not less than 1 decitex per filament, it being more preferred that thickness thereof be such that this is not less than 1.2 decitex. For example, for 30-decitex 24-filament yarn, this would be 1.25 decitex per filament; and for 50-decitex 40-filament yarn, this would also be 1.25 decitex per filament. Furthermore, for 56-decitex 30-filament yarn, this would be 1.87 decitex per filament. By adjusting the number and thickness of filaments in this fashion, it will be possible to reduce the amount of water that is retained, and to make it less likely to get heavy, and also faster to dry, when wet.

As thermally fusible polyurethane elastic fiber in accordance with the present invention, Mobilon (registered trademark) R, R-L, K-L, R-LL, and so forth manufactured by Nisshin Spinning Co., Ltd., may be cited as examples. This thermally fusible polyurethane elastic fiber is one of the types of fiber that are generally referred to as “spandex,” such fibers being capable of use in which following plated knitting therewith they are subjected to heat-set treatment in which saturated steam at, e.g., 120° C. is directed thereat to cause the elastic fibers to thermally fuse together.

Note that while the polypropylene cannot be said to be highly heat-resistant as it exists after it has been made into bare jersey knit fabric as a result of plating of polypropylene and polyurethane elastic yarn, it is preferred that heat-set treatment be carried out for dimensional stability due to the tendency for wrinkles to form. It is generally the case when carrying out heat-set treatment that, where possible to employ a temperature as high as 150° C. to 200° C., doing so will make for good ease of operations and make it possible to reliably obtain heat-set effect. However, with the polypropylene of the present invention, even at on the order of 140° C. to 160° C., heat resistance cannot be described as good, as there is liable to be impairment of texture and so forth.

Therefore, in accordance with the present invention, as elastic yarn which is combined with polypropylene multifilament, particularly preferred among thermally fusible polyurethane elastic fibers are yarns capable of being thermally fused at low temperature, low-temperature-compatible thermally fusible polyurethane elastic fibers capable of being thermally fused in saturated steam at 130° C. or less being preferred. As fibers that soften and are capable of being thermally fused at 120° C. or less, Mobilon R-L, K-L, R-LL, and so forth may be cited as favorable examples.

The heat-set method employs a heat-set treatment apparatus, the knit textile being subjected to saturated steam while it is inserted within a mold, this being carried out by causing heat-setting to occur in such fashion as to be accompanied by thermal fusion. With regard to the temperature of the saturated steam in such case, because the relationship governing the dependence on the pressure of the steam being supplied thereto is known, saturated steam of desired temperature may, for example, be obtained by adjusting the pressure of a boiler. When carrying out heat-setting, employment, for example, of saturated steam at 100° C. to 130° C.—saturated steam at 105° C. to 125° C. being particularly preferred—will make it possible to achieve the desired knit width, without formation of wrinkles, and without impairment of texture, and to obtain knit textile of prescribed shape. Treatment time during such heat-setting is 2 to 120 seconds, 5 to 60 seconds being preferred. At the working examples, this was carried out for 20 seconds.

Of course, besides employment of saturated steam, it is also possible to carry out heat-set treatment by causing dry heat within a range such as will not cause texture to be sacrificed, e.g., heat at 130° C. or 140° C., to be directed thereat.

Where heat-set temperature was as high as 150° C., wrinkles became prominent and there was impairment of texture. On the other hand, when heat-setting was carried out at 130° C. or lower, wrinkles tended not to be prominent, form stability and dimensional stability were within acceptable tolerances, and texture tended not to be impaired. When the polypropylene multifilament yarn exceeds 56 decitex, because wrinkles tend to become prominent, particular ingenuity is required with regard to heat-set temperature and the temperature characteristics of the elastic yarn.

Plating is carried out while the elastic yarn is stretched to an elongation of 1.5 times to 2.3 times, this being such that the degree of stretching is less than the stretching to 2.5 times to 3.3 times that would normally be employed at the procedure where these are knitted together. Stretching to 1.5 times to 2.1 times is more preferred, and stretching to 1.5 times to 2.0 times is still more preferred. At the working examples, DR was 1.75.

By thus keeping draft ratio (DR) low, the pre-lamination fabric will tend not to be wrinkled and will tend to exhibit dimensional stability. Because polypropylene has low heat resistance, making it impossible to employ a high heat-set temperature, it would be difficult to attempt to achieve further dimensional stability through heat-set treatment, so the draft value is made low in advance so as to prevent the elastic yarn from being overstretched. By so doing, because upon being stretched the fabric will gently recover, it will be less likely to produce a tight feeling when worn but will make it possible when worn to produce a natural feeling that allows it to be worn without discomfort.

Drying Characteristics

Observations were made regarding the change in weight following washing in water of wetsuit fabric comprising sponge sheeting made of foam rubber of thickness 2 mm to which polypropylene bare jersey knit fabric (p.p. jersey) was laminated, this constituting a working model of the present invention; and a full wetsuit employing wetsuit fabric at which Nylon jersey knit was laminated to sponge sheeting made of foam rubber of thickness 2 mm. Results are shown in TABLE 1.

TABLE 1 Item name PP Jersey Nylon Jersey Weight when dry (g) 978 978 Elapsed time PP Jersey Nylon Jersey After 30 minutes Weight (g) 1440 1764 % 147% 181% Increase in weight (g) 462 792 After 60 minutes Weight (g) 1380 1692 (after 1 hour) % 141% 174% Decrease in weight (g) 60 72 After 120 minutes Weight (g) 1308 1608 (after 2 hours) % 134% 165% Decrease in weight (g) 72 84 After 180 minutes Weight (g) 1272 1536 (after 3 hours) % 130% 158% Decrease in weight (g) 36 72 After 300 minutes Weight (g) 1200 1428 (after 5 hours) % 123% 147% Decrease in weight (g) 72 108

Despite the fact that the dry weight of each was more or less equivalent, increase in weight after 30 minutes had elapsed following washing in water was such that increase in weight of the p.p. jersey was 462 g while the increase for the Nylon jersey which served as comparative example was 792 g, the difference due to the increase in weight as a result of absorption of water by Nylon being striking. These values may be considered to be the weights during use when in a wet state. Those difference in increased weight Because when is such state there is a large change to what would otherwise be a lightweight wetsuit, a difference in weight of 300 g will from the perspective of the wearer constitute a large difference in terms of ease of movement.

It was only after drying for 5 hours that the weight of the Nylon jersey finally was on the same order as that of the p.p. jersey immediately following its becoming wet. On the other hand, as drying of the p.p. jersey had progressed to the point where this was 1200 g, because the water content was half that of the Nylon jersey or less, it is clear that the p.p. jersey wetsuit was the faster-drying of the two.

Note that the p.p. jersey of the working example required 1185 minutes (approximately 20 hours) to completely dry. On the other hand, because the Nylon jersey was still not dry even after 24 hours had elapsed, it was confirmed that this would present an obstacle to use, since it would have to be used while still wet when used every day for a continuous period.

Hygroscopicity

Hygroscopicity of the working example being 15% while hygroscopicity of the Nylon jersey of the comparative example being 28%, it was confirmed that the p.p. jersey was the more nonhygroscopic of the two.

Antibacterial Characteristics

As shown in TABLE 2, investigation was carried out with respect to the antibacterial characteristics of the p.p. jersey which was a working model of the present invention, and the W/N (woolly nylon) jersey of the comparative example. The antibacterial characteristics of the p.p. jersey were superior to those of the Nylon jersey.

Note that as the values shown at TABLE 2 are logarithmic, the value of 1.30 at the working example indicates that this had more or less reached the minimum value. Note that whereas for comparison purposes it is indicated that the Nylon jersey when new had somewhat fair antibacterial characteristics, this being 2.67, but that after 100 wash cycles the antibacterial characteristics of the Nylon jersey had deteriorated to 4.11 due to loss of the water repellant coating at the surface as a result of use. Thus, the antibacterial characteristics of the Nylon jersey deteriorated as a result of use. For reasons such as the fact that urination is sometimes performed while wearing the wetsuit, and because the environment in which it is used is not necessarily clean, differences in antibacterial characteristics will over a long period of time be accompanied by differences in smell and so forth, which will result in a different feeling when worn.

TABLE 2 Antibacterial Characteristics (Test Results) Common logarithm of live bacteria count (difference between largest and smallest) Immediately following After culturing Antibacterial No. Sample inoculation for 18 hours activity value (1) PP jersey Original item 4.49 (0.0) 1.30 (0.0) 5.7 (2) W/N jersey Original item 4.53 (0.1) 2.67 (1.8) 4.3 Control sample/standard fabric 4.58 (0.0) 6.96 (0.0) Growth value (100% cotton; white fabric) F: 2.4 Note: Test bacteria suspension to which surfactant (Tween 80) had been added was used. Test procedure: JIS L1902: 2015; bacterial solution absorption method Bacterial variety used for testing: Golden Staphylococcus/Staphylococcus aureus NBRC12732 Washing method: In accordance with washing method (standard washing procedure) for SEK Mark textile products; Japan Textile Evaluation Technology Council (a general incorporated association).

Water Repellant Properties

Investigation was carried out with respect to the situation in terms of change in water repellant properties following abrasion testing in accordance with JIS L 1092 of the p.p. jersey of the working example and the W/N jersey (jersey made of woolly nylon; water-repellant coating applied to surface) of the comparative example.

Following 10 cycles, 50 cycles, 100 cycles, or 500 cycles of abrasion treatment, spray testing was carried out in which water droplets were sprayed on the fabric, the degree to which water was repelled being evaluated by ranking this between 1 and 3 (testing was performed three times). A ranking of 3 indicated that water was repelled to a high degree, while a ranking of 1 indicated that there was no repelling of water.

1: The entire surface became moist.

2: Half of the surface became moist, and small individual spots of moisture were observed to penetrate the cloth.

3: The surface was moistened by small individual droplets of water.

Abrasion treatment was carried out using a uniform abrasion tester, 0.1 ml of water being sprayed onto the surface to be abraded, following which a prescribed number of cycles of abrasion treatment was performed on a common bolt of cloth by applying a compressive load of 4.45 N thereto. Results for 500 cycles are shown in TABLE 3, while results for 10, 50, and 100 cycles of abrasion treatment are shown in TABLE 4.

For the Nylon jersey, ability to repel water was somewhat inferior after a mere 10 cycles of abrasion treatment, and by 100 cycles the ability to repel water had almost completely disappeared. Similar results were observed after 500 cycles. While this Nylon jersey was such that the surface thereof had been coated as a result of having been subjected to a water repellant treatment, because the water repellant properties of the Nylon jersey were rapidly lost as a result of abrasion and/or deterioration, it was confirmed that it had a greater tendency to absorb water and dry slowly.

On the other hand, for the p.p. jersey of the present invention, ability to repel water was unchanged, continuing to be ranked as a 3 even after 500 test cycles, water repellant properties being maintained in the same state as they were at the beginning.

TABLE 3 Test Results (1) PP (2) W/N Test Test Item jersey jersey Procedure Degree to which water 3, 3, 3 1, 1, 1 JIS L 1092 repelled (ranking) Spray testing

Abrasion treatment: Uniform abrasion tester was used
0.1 ml of water sprayed onto surface to be abraded, following which 500 cycles of abrasion performed on common bolt of cloth by applying 4.45 N compressive load thereto

TABLE 4 Test Results (1) PP (2) W/N Test Test Item jersey jersey Procedure Degree to which After 10 cycles of 3, 3, 3 2, 2, 2 JIS L 1092 water repelled abrasion treatment Spray testing (ranking) After 50 cycles of 3, 3, 3 2, 1, 1 abrasion treatment After 100 cycles of 3, 3, 3 1, 1, 1 abrasion treatment

Abrasion treatment: Uniform abrasion tester was used
0.1 ml of water sprayed onto surface to be abraded, following which 10, 50, or 100 cycles of abrasion performed on common bolt of cloth by applying 4.45 N compressive load thereto

Thermal Retention Properties

Investigation was carried out with respect to the situation in terms of retention of body temperature with the p.p. jersey wetsuit working model versus the Nylon jersey comparative model when each was used to engage in surfing in seawater for 50 minutes while wearing the wetsuit.

Body surface temperature directly beneath the wetsuit which had fallen to 26° C. due to seawater upon entering the water increased to 32° C. over the course of 4 minutes. Thereafter, while the working model was able to maintain a temperature of 31.5° C., temperature dropped to 30.5° C. with the Nylon jersey. Thus, occurrence of a difference in the body surface temperature when the wetsuit was worn was due to the fact that, because the outer layer of the Nylon jersey became wet, there was a greater tendency for it to become cool due to the heat of vaporization.

Stretchability

At the polypropylene jersey of the working model of the present invention, where elastic yarn comprising thermally fusible polyurethane elastic fiber was further knitted together therewith in such fashion that the degree of stretching thereof was 2 times or less and this was heat-set to cause the elastic yarns to thermally fuse with each other, it was possible during stretching to cause this to be stretched out without needing to apply much force.

For example, with a wetsuit fabric in which there was lamination of bare jersey knit fabric comprising 33-decitex 24-filament polypropylene multifilament yarn and 33-decitex thermally fusible polyurethane elastic fiber, the force necessary to stretch this by 50% was 0.8 N in the wale direction (longitudinal stretching) of the knit fabric, and was 0.2 N in the course direction (transverse stretching). (In accordance with the method of JIS 1096 B, the force required to cause an elongation of 50% relative to the unelongated length of a test piece of width 5 cm (stretching force at low elongation) was measured. Elongation rate: 20 cm/min; chuck separation: 20 cm.) It was confirmed that stretching of this was extremely good, elongation on the same order as that of Nylon being adequately achievable.

Furthermore, with a wetsuit fabric in which there was lamination of bare jersey knit fabric comprising 56-decitex 48-filament polypropylene multifilament yarn, when the knit fabric was stretched to an elongation of 2.9 times, stretching was accomplished by 1.8 N in the wale direction, and 0.8 N in the course direction.

EXPLANATION OF REFERENCE NUMERALS

1 Wetsuit fabric
2 Sponge sheeting made of chloroprene foam rubber
3 Bare jersey knit fabric
4 Outer layer face
5 Inner layer face
6 Polypropylene multifilament yarn
7 Thermally fusible polyurethane elastic fiber

Claims

1. A fabric for a wetsuit wherein weft knit textile cloth comprising bare jersey knit fabric at which polypropylene multifilament yarn and elastic yarn have been knit in plating fashion while said elastic yarn was stretched to an elongation of 1.5 times to 2.0 times, exclusive of 2.0 times, is laminated to either or both faces of a sponge sheet made of chloroprene foam rubber.

2. The fabric for a wetsuit according to claim 1 characterized in that the elastic yarn is thermally fusible polyurethane elastic fiber, and the elastic yarns in the weft knit textile are thermally fused to each other.

3. The fabric for a wetsuit according to claim 1 characterized in that the elastic yarns are in a state of having been thermally fused to each other by heat-setting at 100° C. to 140° C.

4. The fabric for a wetsuit according to claim 1 characterized in that the polypropylene multifilament yarn comprises not greater than 30 filaments, thickness thereof being such as to correspond to 20 decitex to 56 decitex.

5. The fabric for a wetsuit according to claim 1 characterized in that the polypropylene multifilament yarn is such that thickness thereof corresponds to 20 decitex to 56 decitex, and thickness per filament therein corresponds to not less than 1 decitex.

6. A wetsuit employing the fabric for a wetsuit according to claim 1.

7. A fabric for a wetsuit wherein weft knit textile cloth comprising bare jersey knit fabric at which polypropylene multifilament yarn and elastic yarn have been knit in plating fashion while said elastic yarn was stretched to an elongation of 1.5 times to 2.0 times, exclusive of 2.0 times, is laminated to at least an outer layer face of a sponge sheet made of chloroprene foam rubber.

8. The fabric for a wetsuit according to claim 7 characterized in that the elastic yarn is thermally fusible polyurethane elastic fiber, and the elastic yarns in the weft knit textile are thermally fused to each other.

9. The fabric for a wetsuit according to claim 7 characterized in that the elastic yarns are in a state of having been thermally fused to each other by heat-setting at 100° C. to 140° C.

10. The fabric for a wetsuit according to claim 7 characterized in that the polypropylene multifilament yarn comprises not greater than 30 filaments, thickness thereof being such as to correspond to 20 decitex to 56 decitex.

11. The fabric for a wetsuit according to claim 7 characterized in that the polypropylene multifilament yarn is such that thickness thereof corresponds to 20 decitex to 56 decitex, and thickness per filament therein corresponds to not less than 1 decitex.

12. A wetsuit employing the fabric for a wetsuit according to claim 7.