GB2103111A - Wind-passing sheet - Google Patents

Abstract

A wind-passing sheet usable as a wind-breaking sheet, concrete-aging sheet, or sports net comprises a substrate consisting of a coarse fabric composed of a number of yarns including at least warps and wefts, said warps and wefts, respectively, being spaced from each other and extending in parallel to each other; and a covering layer coating therewith the yarns in the substrate and comprising a polymeric material having a melting point of at least 5 DEG C below the melting point of thermally decomposing point of said yarns, the yams being fixed to each other at intersecting points thereof with the covering polymeric material layer.

Description

SPECIFICATION Wind-passing sheet The present invention relates to a wind-passing sheet. More particularly, the present invention relates to a wind-passing sheet useful for agriculture, forestry, civil engineering, and construction industries. Still more particularly, the present invention relates to a wind-passing sheet which is weldable by means of heat treatment and/or high frequency treatment.

Wind-passing sheets are used, for example, as wind-breaking nets or cement-curing nets.

Conventional wind-passing sheets consist of coarse woven or knitted fabrics produced from fiber yarns consisting of a polyvinyl chloride resin or polyvinylidene chloride resins or from fiber yarns coated with the above-mentioned resin or resins.

In the case where the wind-passing sheet is composed of the polyvinyl chloride resin fiber yarns or of polyvinylidene chloride resin fiber yarns, when the sheet is subjected to a heat or high frequency welding procedure, the fiber yarns per se are melted and adhered to each other and, therefore, the welded portion of the sheet exhibits a decreased mechanical strength.

In another case where the sheet is produced from resin-coated fiber yarns by means of a weaving or knitting process, the resin-coated fiber yarns exhibit an undesirably large frictional factor which causes the weaving or knitting process to exhibit a poor productivity. Also, the coating layers formed on the fiber yarns cause the thickness of portions of the sheet wherein the fiber yarns intersect with each other to be excessively large and, therefore, handling of the resultant sheet is difficult and the appearance of the sheet is unsatisfactory.

Furthermore, in both the above-mentioned cases, the resultant sheet exhibits great defects in that the fiber yarns in the sheet tend to easily slip on each other and in that the sheet is excessively bulky and rigid and, therefore, is difficult to handle.

This invention provides a wind-passing sheet which exhibits an adequate wind-passing property and shading property, and a satisfactory mechanical strength and flexibility and is useful for the agriculture, forestry, civil engineering, and construction industries.

The invention also provides a wind-passing sheet which is capable of being welded by means of a heat treatment or high frequency treatment so that the welded portion of the sheet exhibits a satisfactory mechanical strength.

The invention further provides a wind-passing sheet in which the yarns are firmly fixed to each other so as to prevent undesirable slipping and fraying of the yarns.

The invention still further provides a windpassing sheet having an even surface and a satisfactory appearance.

According to the invention a wind-passing sheet comprises: a substrate consisting of a coarse fabric composed of a number of yarns including at least warps and wefts, said warps and wefts, respectively, being spaced from each other and extending parallel to each other; and a covering layer coating the yarns in said substrate and comprising a polymeric material having a melting point of at least 50C below the melting point or thermally decomposing point of said yarns, said yarns being fixed to each other at intersecting points thereof by said covering polymeric material layer.

It is preferable that the wind-passing sheet be welded by applying a heat treatment and/or a high frequency treatment to the covering polymeric material layer.

It is also preferable that the covering polymeric material layer in the wind-passing sheet be porous.

It is, furthermore, preferable that the composite yarns composed of the yarns and the covering layer thereon be flattened in a direction parallel to the surface of the wind-passing sheet.

The invention will now be described in greater detail by way of example with reference to the drawings, in which: Figure 1 shows a structure of a plain weave usable as a substrate of the wind-passing sheet of the present invention, Fig. 2 shows a structure of a gauze weave usable as a substrate of the wind-passing sheet of the present invention, Fig. 3 shows a structure of a leno weave usable as a substrate of the wind-passing sheet of the present invention, Fig. 4 shows a surface view of a wind-passing sheet of the present invention containing a coarse plain weave as a substrate thereof, Fig. 5 shows a cross-sectional profile of the sheet indicated in Fig. 4 along line V-V, Fig. 6 shows a cross-sectional profile of the sheet indicated in Fig. 4 along line VI--VI, Fig. 7 shows a manner of bonding two edge portions of sheets to each other, Fig. 8 shows another manner of bonding two edge portions of sheets to each other, Fig. 9 shows a structure of a substrate of the wind-passing sheet of the present invention in which wefts are arc-formed, Fig. 10 shows a manner of bonding two edge portions of sheets each containing the substrate indicated in Fig. 9, Fig. 11 shows another manner of bonding two edge portions of sheets each containing the substrate indicated in Fig. 9, Fig. 1 2 shows another structure of a substrate usable for the present invention, Fig. 13 shows still another structure of a substrate usable for the present invention, Fig. 14 shows a manner of bonding two edge portions of sheets, Fig. 1 5 shows another manner of bonding two edge portions of sheets, Fig. 1 6 shows still another manner of bonding two edge portions of sheets, Fig. 1 7 shows further still another manner of bonding two edge portions of sheets, Fig. 1 8 shows a manner of bonding two edge portions of sheets by using a reinforcing sheet, Fig. 1 9 shows another manner of bonding two edges of sheets by using a reinforcing sheet, Fig. 20 shows still another manner of bonding two edges of sheets by using two reinforcing sheets, Fig. 21 is a cross-sectional profile of an edge portion of a wind-passing sheet of the present invention having a reinforcing rope and an eyelet, Fig. 22 is a plane view of the edge portion of the sheet indicated in Fig. 21, Fig. 23 through 40 each shows a crosssectional profile of an edge portion of a windpassing sheet of the present invention having an eyelet, a reinforcing rope, and sheets and/or threads, Fig. 41 shows a plane view of a wind-passing sheet of the present invention having an attachment having a desired pattern and bonded to the sheet, Fig. 42 shows a cross-sectional view of a sheet having an attachment bonded to one surface of the sheet, Fig. 43 shows another cross-sectional view of a sheet having the attachment bonded to one surface of the sheet, Fig. 44 shows a cross-sectional view of a sheet having two symmetrical attachments bonded to both surfaces of the sheet, and Fig. 45 shows a cross-sectional view of a sheet having two symmetrical attachments bonded to two surfaces of the sheet.

The wind-passing sheet of the present invention comprises a substrate consisting of a coarse fabric consisting of a number of yarns including of at least warps and wefts and a covering layer coating the yarns in the substrate.

The coarse fabric may be a woven fabric or knitted fabric having a number of holes formed between the yarns and, therefore, capable of allowing wind to pass therethrough.

The yarns from which the coarse fabric substrate is formed are not limited to a specific composition. The yarns may be composed of at least one type of fibers selected from the group consisting of non-melting fibers, for example, cellulosic fibers such as cotton, hemp, viscose rayon, and cupra, inorganic fibers having a high melting point, for example, glass fibers and metallic fibers, organic synthetic fibers having a high melting point, for example, polyesters and other organic synthetic fibers having no melting point, for example, water-insolubilized polyvinyl alcohol fibers. The yarns are not limited to a specific type, that is, the yarns may be spun yarns, multifilament yarns, split yarns, or tape yarns.

The preferable yarns for the warp and wefts of the coarse fabric of the present invention are selected from polyethylene terephthalate multifilament yarns having a melting point of approximately2600C and a total of from 100 to 5000 deniers and water-insolubilized polyvinyl alcohol multifilament yarns having a total denier of from 100 to 5000 and a thermal decomposition point of from approximately 2200C to approximately 2300C. The abovementioned types of yarns have a satisfactory mechanical strength and heat resistance.

The coarse fabric usable as the substrate of the wind-passing sheet of the present invention is not limited to that of a specific structure. For example, the coarse fabric may be a plain weave, indicated in Fig. 1, consisting of warps 1 and wefts 2 or a gauze weave, indicated in Fig. 2, consisting of wefts 3, standard warps 4a, and crossing warps 4b. Standard warps 4a and crossing warps 4b intersect each other and also intersect wefts 3.

The coarse fabric may be a leno weave, indicated in Fig. 3, wherein a layer of wefts 5 extending parallel to each other is superimposed thereon with a layer of warps 6 extending parallel to each other and warps 6 and wefts 5 are bonded at intersecting points thereof with bonding yarns 7 so as to form a body of fabric.

In the coarse fabric usable as a substrate of the wind-passing sheet of the present invention, it is preferred that the gaps between one warp and the adjacent one and between one weft and the adjacent one be in the range of from 0.5 to 15 mm, more preferably from 1.0 to 10 mm. The gaps form holes for passing wind therethrough.

The coarse fabric usable for the present invention preferably has a weight of from 40 to 500 g/m2, and each hole in the coarse fabric has an area in a range of from 0.25 to 225 mm2, more preferably from 1 to 100 mm2.

The yarns in the substrate are coated with a covering layer comprising a polymeric material having a melting point of at least SOC, preferably at least 1 00C and still more preferably 200C to 300C, below the melting point or thermal decomposition point of the yarns in such a manner that the yarns are fixed to each other at the intersecting points thereof by the covering polymeric material layer.

In Fig. 4, wind-passing sheet 10 is composed of composite warps 11 and composite wefts 12, each of which consists of a yarn and a coating layer. In Fig. 5, composite weft 12 is composed of weft 1 2a and covering layer 13. At portion 14 of composite weft 12, at which weft 1 2a intersects warp 11 a, weft 1 2a directly contacts warp 11 a and the intersecting portion of warp 11 a and weft 1 2a is coated together with covering layer 13 so as to firmly fix warp 11 a to weft 12a.

It is important that the covering polymeric material layer has a melting point of at least 50C, preferably at least 1 00C and more preferably 1 00C to 200 C, below the melting point or the thermal decomposition point of the yarn. If the difference between the melting point of the covering polymeric material layer and the melting point or the thermal decomposition point of the yarn is less than 50C, the heat- or high-frequencywelding procedure or a heat-pressing procedure applied to the resultant wind-passing sheet may result in undesirable shrinking, melting, and/or deterioration.

Usually, the polymeric material for forming the covering layer preferably has a melting point in the range of from 1000C to 2500C, and, therefore, is selected from the group consisting of polyvinyl chloride resins, polyurethane resins, and ethylene-vinyl acetate copolymer resins.

The covering layer may be porous and may be composed of a foamed polymeric material. The porous covering layer is effective for causing the resultant wind-passing sheet to be light and flexible, to look heavy, and to be easily deformed, for example, pressed. The thickness of the composite yarn containing the porous polymeric material layer is remarkably larger than that of another composite yarn containing a dense polymeric material layer in the same weight as the porous polymeric material layer. Also, if the thickness of the composite yarn containing porous polymeric material layer is the same as that of another composite yarn containing the dense polymeric material layer, the weight of the former composite yarn is remarkably smaller than that of the latter composite yarn.

The pores formed in the porous covering polymeric material layer may be independent from each other or may be connected to each other or a portion of the pores may be independent from each other and the remaining portion of the pores may be connected to each other.

The size of the pores and the porosity of the porous covering layer are not limited to specific values and, therefore, can be varied to desired values. However, it is preferable that the pores in the covering layer be fine. The pores may be distributed throughout the entire covering sheet or may be distributed in a limited portion of the covering sheet. Especially, it is preferable that the outer surface portion of the covering layer be free from pores and that the outer surface be smooth.

The weight of the covering layer is not limited to a specific range of values. However, it is preferable that the weight of the covering layer corresponds to 50% or more, more preferably 70% to 200%, of the weight of the substrate. In the case where the covering layer is porous and the resultant wind-passing sheet is not subjected to the heat- or high-frequency-welding procedure, the weight of the covering layer may be in the range of from 20% to 30% of the substrate.

The covering layer can be formed by impregnating or coating a substrate with a predetermined amount of solution or emulsion containing a polymeric material, by drying the layer of the solution or emulsion so as to form a solid covering layer consisting essentially of the polymeric material around the yarns in the substrate, and, if necessary, by curing the solid covering layer at an elevated temperature.

Application of the solution or emulsion containing the polymeric material can be carried out by any conventional method, for example, the immersing-squeezing method, the spraying method, the coating method or the brushing method.

In the coating procedure, the peripheral surfaces of the yarns in the substrate, except for portions of the yarns in which the yarns contact each other, are coated with the covering layer.

Especially, in portions of the substrate in which the yarns intersect each other, the intersecting portions of the yarns are coated together by the covering layer so as to fix the yarns to each other with the covering layer, in the manner indicated in Fig. 5.

The solution or emulsion may contain, in addition to the polymeric material, any conventional additive, for example, flameretardant, for example, antimony trioxide; a coloring material, for example a pigment or dye; and antioxidant; an ultraviolet ray-absorbing agent; a blowing agent and other additives.

In the wind-passing sheet of the present invention, it is preferable that each composite yarn composed of a yarn and a covering layer be flattened in parallel to the surface of the sheet. In Fig. 6, which shows a cross-sectional profile of weft 12, weft 1 2a and a covering layer formed around weft 1 2a are flattened together. The intensity of flattening is not limited to a specific value. However, it is preferable in the crosssectional profile of a flattened composite yarn as indicated in Fig. 6 that the ratio of length lr of the profile in the direction parallel to the surface of the sheet to width 12 of the profile in the direction at right angles to the surface of the sheet be in the range of from 1.3:1 to 5:1, more preferably 2:1 or 5:1.

The flattened composite yarns are effective for increasing the softness and the flexibility of the sheet and for decreasing the bulkiness of the sheet.

The flattening procedure for the sheet can be carried out by pressing the sheet having the substrate and the coating layer by means of a pressing machine, an embossing apparatus, or a calender. The pressing operation may be effected while heating the sheet. The pressing pressure and temperature are variable depending on the type and amount of the polymeric material covering layer, the type of yarns in the substrate, and the desired flattening intensity. In the case where the pressing operation is carried out by using a pair of pressing rolls, it is preferable that the pressing temperature by in the range of from 200C to 1 500C, more preferably 500C to 1 300C, and that the pressing pressure be in the range of from 0.1 to 50 kg/cm, more preferably from 1.0 to 20 kg/cm.The pressing operation may be carried out at room temperature without heating the sheet.

The pressing operation applied to the sheet is effective for increasing the bonding strength among the yarns so as to prevent slipping and fraying of the yarns. Accordingly, the flattened wind-passing sheet of the present invention exhibits an increased evenness, an enhanced durability, and a satisfactory mechanical strength in addition to the increased softness and flexibility and an adequate bulkiness.

In the flattened wind-passing sheet of the present invention, it is preferable that the coarse fabric for the substrate be composed of yarns which are capable of being easily flattened by a pressing procedure.

The yarns which are capable of being easily flattened are preferably so-called soft twist yarns but are not always limited thereto. Non-twist yarns can be used for the substrate. However, non-twist yarns are not preferable because they are difficult to handle and also are difficult to weave.

The flattened yarns are fixed in a flat form by the flattened covering polymeric material layer.

Therefore, it is necessary that the polymeric material be thermoplastic.

In the process for flattening the sheet by means of a pair of pressing rolls, the peripheral surfaces of the pressing rolls may be smooth and even or may be finely engraved in a desired regular or irregular pattern. When the peripheral surfaces of the pressing rolls are smooth, the surfaces of the resultant sheet are smooth. When the peripheral surfaces of the pressing rolls are chased, the surfaces of the resultant sheet exhibit the desired pattern of fine engravings. The pattern of the engravings on one surface may be the same as or different from that on the opposite surface of the resultant sheet. The fine engraving formed on the sheet surfaces are effective not only for improving the appearance and gloss of the sheet but also for increasing the flexibility, softness, and, therefore, handling property of the sheet.The impartment of the fine engravings onto the surfaces of the sheet is quite new in the field of wind-passing sheets.

The wind-passing sheet of the present invention exhibits adequate wind-passing and shading properties, softness, flexibility, and bulkiness and an excellent resistance to slipping and fraying of the yarns.

In the wind-passing sheet of the present invention, it is preferable that the covering polymeric material layer be welded by applying a heat treatment or high-frequency treatment thereto. In this case, a portion of a sheet is superimposed on a portion of another sheet or on another portion of the sheet and superimposed portions are heated at a temperature higher than the melting point of the covering polymeric material layer but lower than the melting point or thermal decomposition point of the substrate by means of a high-frequency heating, hot air heating, or hot plate heating method or another conventional heating method while pressing the superimposed portions. Usually, the welding procedure is carried out preferably by using a hot air heating welder or high-frequency welder.

In Fig. 7, edge portion 15 of a sheet to be welded is superimposed on edge portion 1 6 of another sheet. Superimposed edge portions 1 5 and 16 are press-heated together at an adequate temperature and then cooled to room temperature.

In Fig. 8, edge portions 17 and 16 of two separate sheets are folded and combined in the manner indicated in the drawing. Combined edge portions 1 7 and 1 6 are press-heated together at an adequate temperature and then cooled to room temperature.

In the wind-passing sheet of the present invention, the warps and wefts may extend straightly respectively parallel to each other. In another embodiment, the wefts may extend in an arc form, for example, as indicated in Fig. 9, and in parallel to each other.

In Fig. 9, warps 20 extend straightly parallel to each other and wefts 21 extend in an arc form and parallel to each other. In this case, it is preferable that distance A between a straight line 22 drawn between the end points 21 a and 21 b of one arc-formed weft 21 and the peak point 23 of arcformed weft 21 corresponds to 1% to 5% of length B of straight line 22. For example, in the case where the length B of straight line 22 is 2 m, distance A is preferably in the range of from 2 to 10 cm.

In Fig.10, two separate sheets 24 and 25 are bonded in such a manner that a right edge portion of sheet 24 is superimposed on a left edge portion of sheet 25. In resultant superimposed portion 26, downwardly arcformed wefts 27 of sheet 24 intersect at angles not only with warp 20B but also with downwardly arc-formed wefts 28 of sheet 25, and wefts 28 of sheet 25 intersect at angles with warps 20A in addition to wefts 27 of sheet 24. The superimposed portion is welded at intersecting points of the warps and wefts therein.

Therefore, the resultant welded portion can exhibit an excellent bonding strength.

In Fig. 11, in sheet 30, wefts 32 are downwardly curved, and in sheet 31, wefts 33 are upwardly curved. The right edge portion of sheet 30 is superimposed on the left edge portion of sheet 31 so as to form superimposed portion 34.

In superimposed portion 34, wefts 32 of sheet 30 intersect at angles with wefts 33 and warps B of sheet 31, and wefts 33 of sheet 31 intersect at angles with wefts 32 and warps 20A of sheet 30.

When superimposed portion 34 is press-heated, sheets 30 and 31 are firmly bonded.

In the coarse fabric substrate in the windpassing sheet of the present invention, all the warps and all the wefts may be respectively arranged in a uniform density thereof. In another embodiment, the density of the warps and/or wefts in a portion of the sheet to be welded may be larger than that in the other portion of the sheet.

In Fig. 12, in sheet 35, the density of the warps in portions 36 and 37 to be welded is larger than in the other portion, and the density of the wefts in portions 38 and 39 to be welded is larger than in the other portion.

In Fig. 13, the warps are arranged in a uniform density and the density of the wefts in edge portions 41 and 42 to be welded is larger than that in the remaining portion.

The large density portions of the sheet are effective for increasing the bonding strength of the portion of the sheet which has been welded or sewed.

The wind-passing sheet of the present invention can be welded in any manner. For example, in Fig. 14, sheet 43 is welded to sheet 43 in such a manner that the warps and wefts of sheet 43 are superimposed on the warps and wefts of sheet 44, respectively. In this case, the superimposed portion of the sheets has a very large thickness and it is difficult to maintain the superimposed portion in an accurately superimposed condition during the press-heating operation. In order to eliminate the abovementioned difficulty, it is preferable that two sheets be superimposed on each other in such a manner that at least the warps or wefts in the portion of one sheet to be welded intersect at angles with at least the wefts or warps of the other sheet.

In Fig.15, the wefts of sheet 45 are superimposed on the wefts of sheet 46 in parallel to each other, the warps of sheet 45 intersect at right angles with the wefts of sheet 46, and the warps of sheet 46 intersect at right angles with the wefts of sheet 45. The warps of sheet 45 do not contact the warps of sheet 46.

In Fig. 1 6, the warps of sheet 47 are superimposed on the warps of sheet 48 in parallel to each other, the wefts of sheet 47 intersect at right angles with the warps of sheet 48 , and the wefts of sheet 48 intersect at right angles with the warps of sheet 47. The wefts of sheet 47 do not contact the wefts of sheet 48.

In Fig.17, the warps of sheet 49 intersect at right angles with the wefts of sheet 50 and the wefts of sheet 49 intersect at right angles with the warps of sheet 50. In this case, the warps and wefts of sheet 49 do not contact the warps and wefts of sheet 50, respectively.

The superimposing methods indicated in Figs.

1 5, 1 6, and 1 7 are easily carried out and are effective for making the welded portion of the sheets thin and strong.

In the welding procedure, the portions of the two sheets to be welded may be directly welded.

In another manner, an additional weldable sheet consisting essentially of a thermoplastic polymeric material which can be melted at a temperature similar to the melting point of the covering polymeric material layers of the sheets is inserted between the portions of the sheets to be welded.

In Fig. 18, an edge portion of sheet 51 is superposed on an edge portion of sheet 52, and an additional weldable sheet is inserted between the superposed portions of sheets 51 and 52.

In still another method a side edge of a sheet is brought into contact with a side edge of another sheet and at least one surface of the contacting portions of the sheets is covered with an additional weldable sheet.

In Fig. 19, a side edge of sheet 54 is brought into contact with a side edge of sheet 55, and additional weldable sheet 53 is placed on the lower surface of the contacting portion of sheets 54 and 55. When a welding operation is applied to additional weldable sheet 55, sheets 54 and 55 and bonded to each other by additional sheet 53.

In Fig. 20, two sheets 54 and 55 which contact each other at the side edges thereof are bonded by additional sheets 53a and 53b placed, respectively, on the upper and lower surfaces of the contacting portion of sheets 54 and 55.

The additional weldable sheet preferably consists essentially of the same polymeric material as that in the covering layer. However, as long as the additional sheet exhibits a satisfactory weldability to the covering layer, the polymeric material of the additional sheet may be different from that of the covering layer. It is preferable, however, that the additional sheet consist essentially of at least one member selected from polyvinyl chloride, polyurethane, and ethylenevinyl acetate copolymers and have a thickness of from 0.05 to 2.0 mm. The additional sheet may be composed of a substrate consisting of a woven, knitted, or non-woven fabric consisting of natural or artifical organic or inorganic fibers and at least one coating layer formed on at least one surface of the substrate and consisting of a weldable thermoplastic resin.The substrate is effective for increasing the bonding strength of the welded portion of the sheets.

The welded portion of the sheets may be reinforced by additionally applying a sewing operation thereto.

The wind-passing sheet of the present invention may be provided with at least one eyelet. Usually, the eyelet is formed in an edge portion of the sheet. In this case, it is preferable that the edge portion of the sheet be folded at least once and that the eyelet be formed in the folded portion of the sheet. Also, it is preferable that the edge portion of the sheet in which the eyelet is formed have a larger density of warps or wefts than that in the remaining portion of the sheet.

In Figs. 21 and 22, sheet 60 has edge portion 61 having a larger density of warps than that in remaining portion 62. Edge portion 61 is folded once and reinforcing rope 64 is inserted into turned portion 63 and folded edge portion 61 is heat-pressed at an elevated temperature so as to form a reinforced edge portion. A desired number of eyelets 66 are formed in reinforced edge portion 61 of sheet 60. Eyelet 66 may be formed by a grommet as indicated in Fig. 21.

The rope inserted into the folded portion of the sheet may be omitted as indicated in Fig. 23. In Fig. 24, an edge portion of sheet 60 is folded twice. In Fig. 25, an edge portion of sheet 60 is folded once and reinforcing sheet 67 is inserted into the folded portion of sheet 60. In Fig. 26, an edge portion of sheet 60 is folded three times. In Fig. 27, an edge portion of sheet 60 is folded three times and reinforcing rope 64 is inserted into the first turned portion. In Fig. 28, an edge portion of sheet 60 is folded twice and reinforcing rope 64 is inserted into the first turned portion thereof. In Fig. 29, an edge portion of sheet 60 is folded once and the folded portion of sheet 60 is covered with reinforcing sheet 67.In Fig. 30, an edge portion of sheet 60 is folded once and the upper surface and the lower surface (except for the round side surface) of the folded portion of sheet 60 are covered with reinforcing sheets 67a and 67b, respectively. In Fig. 31, an edge portion of sheet 60 is folded once and only the lower surface of the folded portion of the sheet is covered with reinforcing sheet 67. In Fig. 32, an edge portion of sheet 60 is folded once, reinforcing rope 64 is inserted into the fold in the folded portion, and the outer surface of the folded portion is entirely covered with reinforcing sheet 67.In Fig. 33, an edge portion of sheet 60 is folded once, reinforcing rope 64 is inserted into the turned portion in the folded portion, and the upper surface and the lower surface (except for the surface surrounding rope 64) of the folded portion of the sheet are covered with reinforcing sheets 67a and 67b, respectively. In Fig. 34, an edge portion of sheet 60 is folded once, reinforcing rope 64 is inserted into the fold of the folded portion of the sheet, and reinforcing sheet 67 is inserted into the folded portion of the sheet.

In Fig. 35, an edge portion of sheet 60 is folded once, reinforcing rope 64 is inserted into the fold of the folded portion, and only the lower surface (except for a portion thereof around rope 64) of the folded portion is covered with reinforcing sheet 67.

The folded portion of the sheet may be additionally reinforced by applying a sewing operation thereto.

In Fig. 36, an edge portion of sheet 60 is folded once and the folded portion of sheet 60 is sewed with threads 68.

In Fig. 37, an edge portion of sheet 60 is folded once, rope 64 is inserted into the fold of the folded portion, and the folded portion is sewed with threads 68. In Fig. 38, an edge portion of sheet 60 is folded three times, rope 64 is inserted into the fold of the folded portion, in which fold two layers of the sheet are turned so as to form a space for receiving rope 64, and the folded portion is sewed with threads 68. In Fig. 39, reinforcing sheet 67 is placed on an edge portion of sheet 60 and reinforcing sheet 67 and the edge portion of sheet 60 are folded together once in such a manner that reinforcing sheet 67 is inside of the folded portion. Rope 64 is inserted into the fold of the folded portion. The folded portion of the sheet is sewed with threads 68.In Fig. 40, reinforcing sheet 67 is placed on an endmost part of an edge portion of sheet 60 and edge portion of sheet 60 is folded once so that reinforcing sheet 67 is inside of the folded portion of the sheet. Reinforcing rope 64 is inserted into the fold in the folded portion of sheet 60. The folded portion is further reinforced by being sewed with threads 68.

In the wind-passing sheet of the present invention, a desired number of attachments each having a desired pattern may be adhered to desired portions of the sheet. The attachment is usually composed of a fabric or film designed so as to have a desired pattern. The attachment may be directly bonded to the sheet by applying a heat treatment or high-frequency treatment to the sheet through the attachment while pressing the attachment to the sheet. The attachment may also be bonded to the sheet through an adhesive or bonding material layer formed on a back surface of the attachment. The attachment may be applied to only one surface of the sheet. In another manner, a pair of attachments having symmetrical patterns are adhered to both surfaces of the sheet so that the symmetrical attachments face each other.

For example, in Fig. 41, attachment 70 having a desired pattern is attached to wind-passing sheet 71 consisting of warps 72 and wefts 73.

When the attachment is applied to only one surface of the sheet, it is preferable that the warps and wefts be embedded in an adhesive or bonding material layer formed on a back surface of the attachment. In Fig. 42, yarns 74 in sheet 71 are embedded in adhesive or bonding material layer 75 formed a back surface of attachment 70.

Yarns 74 may be partially exposed to the outside atmosphere as indicated in Fig. 43. However, it is preferable, that regarding the cross-sectional profile of yarn 74, that at least a half of the yarn profile be embedded in adhesive or bonding material layer 75.

When a pair of symmetrical attachments is attached to the sheet in the manner indicated in Fig. 44, it is preferable that adhesive or bonding material layers on attachments 70a and 70b be bonded to each other through yarns 74 of sheet 71 so as to form bonded adhesive or bonding material layer 77 and that yarns 74 be embedded in bonded adhesive or bonding material layer 77.

When a pair of attachments 70a and 70b is asymmetrical, some of yarns 74 in sheet 21 may be partially exposed to the outside of the sheet as indicated in Fig. 45.

The bonding material layer in the attachment may consist of polymeric material the same as or different from that in the covering layer on the yarns.

The adhesive material may be pressure sensitive and may contain at least one polymer selected from natural rubber, synthetic rubbers, regenerated rubbers, polyisobutylene, polyvinyl ethers, polyacrylic ester, polyethylene, polypropylene, ethylene-proplene copolymers, and ethylene-vinyl acetate copolymers. The polymer in the adhesive material may be mixed with an adhesive property-imparting agent consisting of at least one member selected from resin, ester gum, polyterpene resin, petroleum resin, xylene resin, oil-soluble phenolic resin, and coumarone-indene resin. The polymer may be mixed with a plasticizer, fiber, and/or anti-aging agent.

The bonding material may be thermoplastic and may contain the same polymeric material as that in the covering layer.

The following examples illustrate the invention.

Example 1 A gauze weave having the following structure: 500 deniers/2 xl 000 deniers/1 7x7 (yarns/25.4 mm) was produced from polyester multifilament yarns.

The gaps between yarns were 3.5 mmx3.5 mm on the average.

The gauze weave, which was used as a coarse fabric substrate, was impregnated with a polymeric material composition having the following composition.

Amount Component (parts by wt.) Polyvinyl chloride 100 DOP (plasticizer) 80 Stabilizer 1 Antimony trioxide 30 Green pigment 2 Trichloroethylene 25 The resultant impregnated sheet was dried.

The dried sheet contained 100% by dry weight of the polymeric material.

Two pieces of the sheet was superimposed in the manner indicated in Fig. 8, and the superimposed portion was pressed by means of a pair of pressing rolls while blowing thereon hot air having a temperature of 4000C.

The resultant bonded portion exhibited a bonding strength of 45.0 kg/3 cm.

Example 2 The same procedures as those described in Example 1 were carried out with the following exceptions.

1. The sheet impregnated with the polymeric material composition was continuousiy dried in a dryer in such a manner that the center portion of the sheet came behind both the edge portions of the sheet, and the wefts in the sheet curved backwardly. In the resultant sheet, the width of the sheet was 2 mm and distance A (indicated in Fig. 9) was approximately 5 cm.

2. Two pieces of the sheet were superimposed and bonded in the manner indicated in Fig. 10.

The bonding strength of the bonded portion was 60.2 kg/3 cm.

3. Another two pieces of the sheet were superimposed and bonded in the manner indicated in Fig. 11. The bonding strength of the bonded portion was 58.4 kg/3 cm.

Example 3 The same procedures as those described in Example 1 were carried out with the following exceptions.

1. Two pieces of the sheet were superimposed and bonded in the manner indicated in Fig. 14.

The resultant bonded portion exhibited a bonding strength of 45.2 kg/3 cm.

2. Another two pieces of the sheet were superimposed and bonded in the manner indicated in Fig. 1 5. The bonding strength was 55.5 kg/3 cm.

3. Still another two pieces of the sheet were superimposed and bonded in the manner indicated in Fig. 16. The resultant bonding strength was 54.8 kg/3 cm.

4. Further, another two pieces of the sheet were superimposed and bonded in the manner indicated in Fig. 1 7. The resultant bonding strength was 62.4 kg/3 cm.

Example 4 A gauze weave substrate having the following structures was produced from polyester multifilament yarns.

Edge portions.

1000 d/1 x1000d/1 15x7 (yarns/25.4 mm) The remaining portion: 500 d/2x1000 d/1 7x7 (yarns/25.4 mm) The width of each edge portion was 10 cm.

The polymeric material composition of Example 1 was applied to the substrate so that the amount of the resultant covering layer became 100% by weight based on the weight of the substrate.

Each edge portion of the resultant sheet was folded once and a reinforcing rope was inserted into the folded portion of the sheet in the manner indicated in Fig. 21. The folded portion except for the end part thereof surrounding the reinforcing rope was heat-welded by blowing hot air having a temperature of 4000C thereon. A number of eyelets were formed in the welded edge portion of the sheet. The rope was movable through the hollow space formed in the non-welded end part of the folded portion of the sheet.

Example 5 The same procedures as those described in Example 1 were carried out except that the polymeric material composition was of the following composition: Amount Component (parts by wt.) Polyvinyl chloride 100 DOP 80 Stabilizer 1 Antimony trioxide 30 Green pigment 2 Azo-bisformamide (blowing agent) 8 Trichloroethylene 25 The impregnated sheet was heated at a temperature of 1 800C for 3 minutes to gelatinize and foam the composition on the sheet. The resultant sheet contained 70% by weight of the covering layer based on the weight of the substrate.

After the bonding procedure, the bonding strength of the resultant bonded portion of the sheet was 44.0 kg/3 cm.

Example 6 The same procedures as those described in Example 1 were carried out with the following exceptions.

1. While the resultant sheet had a temperature of 600C or more, the sheet was pressed by using a pair of pressing rolls having smooth peripheral surfaces under a pressure of 10 kg/cm. In the pressed sheet, the ratio 11/12 was approximately 2:1.

2. The bonding strength was 45.0 kg/3 cm.

Example 7 The same procedures as those described in Example 1 were carried out with the following exceptions.

1. The polymeric material composition was of the composition as described in Example 5.

2. The amount of the covering layer was 50% based on the weight of the substrate.

3. The appearance of the resultant windpassing sheet was similar to that of Example 6.

4. The pressing procedure was carried out under a pressure of 5 kg/cm.

5. The ratio l,/12 was approximately 2.5:1.

6. The resultant flattened sheet had a proper thickness and exhibited a satisfactory resilience, flexibility, and handling property.

Example 8 The same procedures as those described in Example 2 were carried out with the following exceptions.

1. While the resultant coated sheet had a temperature of 400C or more, the sheet was pressed by using a pair of pressing rolls having finely engraved peripheral surfaces. The pressed sheet exhibited a silk-like gloss and an enhanced flexibility.

2. The bonding strength of the bonded portion of the sheets bonded in the manner indicated in Fig.10 was 62.2 kg/3 cm.

3. The bonding strength of the bonded portion of the sheets bonded in the manner indicated in Fig. 11 was 60.0 kg/3 cm.

Claims (18)

Claims

1. A wind-passing sheet comprising: a substrate consisting of a coarse fabric composed of a number of yarns including at least warps and wefts, said warps and wefts, respectively, being spaced from each other and extending in parallel to each other; and a covering layer coating therewith the yarns in said substrate and comprising a polymeric material having a melting point of at least 50C below the melting point or thermally decomposing point of said yarns, said yarns being fixed to each other at intersecting points thereof with said covering polymeric material layer.

2. A wind-passing sheet as claimed in claim 1, wherein said sheet is capable of being welded by applying a heat treatment and/or a highfrequency treatment to said covering polymeric material layer.

3. A wind-passing sheet as claimed in claim 1 or claim 2, wherein said covering polymeric material layer is porous.

4. A wind-passing sheet as claimed in any one of claims 1 to 3, wherein said warps and wefts are composed of at least one member selected from polyester fibers and water-insolubilized polyvinyl alcohol fibers.

5. A wind-passing sheet as claimed in any one of claims 1 to 4, wherein said polymeric material consists essentially of at least one member selected from the group consisting of polyvinyl chloride, polyurethane, and ethylene-vinyl acetate copolymers.

6. A wind-passing sheet as claimed in any one of claims 1 to 5, wherein said coarse fabric is selected from the group consisting of plain weaves, gauze weaves, and leno weaves.

7. A wind-passing sheet as claimed in any one of claims 1 to 6, wherein said yarns and said covering layer formed around said yarns are flattened together in a direction parallel to the surface of said wind-passing sheet to form flattened composite yarns.

8. A wind-passing sheet as claimed in claim 7, wherein said flattened composite yarns have a cross-sectional profile wherein the ratio of the length (I,) of the cross-section parallel to the surface of the sheet to the width (12) of the crosssection at right angles to the surface of the sheet is in the range of from 1.3:1 to 5:1.

9. A wind-passing sheet as claimed in claim 8, wherein the ratio l,/12 is more than 2:1.

10. A wind-passing sheet as claimed in any one of claims 1 to 9, wherein the surface of said covering layer is smooth.

11. A wind-passing sheet as claimed in any one of claims 1 to 9, wherein the surface of said covering layer is finely roughened.

12. A wind-passing sheet as claimed in any one of claims 1 to 11, wherein said wefts extend in the form of an arc and in parallel to each other.

1 3. A wind-passing sheet as claimed in claim 12, wherein the distance between a straight line drawn between the end points of an arc-formed weft and the peak point of said arc-formed weft corresponds to 1 q/o to 5% of the length of said straight line.

14. A wind-passing sheet as claimed in any one of claims 1 to 13, wherein the gaps between each warp and the adjacent one and between each weft and the adjacent one are in the range of from 0.5 to

15 mm.

1 5. A wind-passing sheet as claimed in any one of claims 1 to 14, wherein the density of said warps and/or said wefts in a portion of said sheet to be welded is larger than that in the remaining portion of said sheet.

1 6. A wind-passing sheet as claimed in any one of claims 1 to 15, wherein at least one edge portion of said sheet is folded at least once and at least one eyelet is formed in said folded edge portion of said sheet.

17. A wind-passing sheet as claimed in claim 16, wherein said folded edge portion of said sheet is reinforced with a reinforcing rope inserted thereinto.

18. A wind-passing sheet as claimed in claim 1 6 or claim 17, wherein said folded edge portion of said sheet is reinforced with at least one reinforcing sheet placed thereon or inserted thereinto.

1 9. A wind-passing sheet as claimed in claim 1, substantially as described herein with reference toanyofFigs.1,2,3,4to6,7,8,9to 11,12,13, 14,15,16,17,18,19,20,21 and 22,23,24, 25, 26, 27, 28, 29, 30, 31,32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, and 45 of the drawings.