GB2155853A - Laminated sheet - Google Patents

Laminated sheet Download PDF

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Publication number
GB2155853A
GB2155853A GB08432821A GB8432821A GB2155853A GB 2155853 A GB2155853 A GB 2155853A GB 08432821 A GB08432821 A GB 08432821A GB 8432821 A GB8432821 A GB 8432821A GB 2155853 A GB2155853 A GB 2155853A
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United Kingdom
Prior art keywords
sheet
porous sheet
base fabric
laminated sheet
elongation
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Granted
Application number
GB08432821A
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GB2155853B (en
GB8432821D0 (en
Inventor
Kanji Kawakami
Shoji Suzuki
Takashi Tago
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Nitto Denko Corp
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Nitto Denko Corp
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Publication date
Priority to JP4022284A priority Critical patent/JPS60183138A/en
Priority to JP21569584A priority patent/JPS6194752A/en
Application filed by Nitto Denko Corp filed Critical Nitto Denko Corp
Publication of GB8432821D0 publication Critical patent/GB8432821D0/en
Publication of GB2155853A publication Critical patent/GB2155853A/en
Application granted granted Critical
Publication of GB2155853B publication Critical patent/GB2155853B/en
Application status is Expired legal-status Critical

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00Layered products comprising a layer of synthetic resin
    • B32B27/12Layered products comprising a layer of synthetic resin next to a fibrous or filamentary layer
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00Layered products comprising a layer of synthetic resin
    • B32B27/32Layered products comprising a layer of synthetic resin comprising polyolefins
    • B32B27/322Layered products comprising a layer of synthetic resin comprising polyolefins comprising halogenated polyolefins, e.g. PTFE
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B3/00Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form ; Layered products having particular features of form
    • B32B3/26Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form ; Layered products having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/02Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
    • B32B5/04Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer characterised by a layer being specifically extensible by reason of its structure or arrangement, e.g. by reason of the chemical nature of the fibres or filaments
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04Interconnection of layers
    • B32B7/05Interconnection of layers the layers not being connected over the whole surface, e.g. discontinuous connection or patterned connection
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04Interconnection of layers
    • B32B7/12Interconnection of layers using interposed adhesives or interposed materials with bonding properties
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2305/00Condition, form or state of the layers or laminate
    • B32B2305/02Cellular or porous
    • B32B2305/026Porous

Abstract

A stretchable waterproof laminated sheet comprises a stretchable base fabric (1) having, and a porous unsintered polytetrafluoroethylene sheet (2) having an elongation larger than that of the base fabric. The sheets are bonded together by, for example, adhesive (3). <IMAGE>

Description

SPECIFICATION Laminated sheet The present invention relates to a laminated sheet having a waterproofness (water repellency) and stretching properties and, more particularly, to a laminated sheet having an improved sewing processability.

Waterproof sheets are expected to find commercial use as the material for various articles such as tents, rain wear, sports wear and diaper covers.

As a waterproof sheet of this type, a sheet has been known which comprises a cloth such as nylon taffeta and a porous sheet of a sintered poiytetrafluoroethylene (hereinafter merely referred to as "PTFE')' which are partially bonded together. This sheet however, has a problem that the feeling of use is poor, although it has a satisfactory waterproofness, since it does not have stretching properties. Moreover, if tension is applied on the sheet, it directly acts on the porous sheet to expand micropores of the porous sheet, resulting in a reduction of waterproofness, or on the partially bonded areas between the porous sheet and fabric to break the bonded areas, causing the separation of the porous sheet from the cloth.

The above problem is marked when the sheet is used in production of sports wear and rain wear for climbing, i.e., wear which is used in sport of the type that the motion is vigorous, or diaper covers, for example. It has therefore been desired to develop sheets having both waterproofness and stretching properties.

Sports wear and diaper covers are generally produced using the waterproof sheet by sewing.

In the course of sewing, needle holes are formed in a base fabric and a sintered PTFE porous sheet by penetration of the sewing machine needle. On the porous sheet, many cracks starting from the needle holes may be caused.

If cracks arise on the needle hole portions of such a sintered PTFE porous sheet, the strength in the vicinity of the needle holes decreases. As a result, during using, wearing or washing the articles, the cracks expand by the stress acting to the sewing portions, resulting in deterioration of the waterproofness, and the practical performance of the articles is lost with a short period of time. Thus, there is the problem on the durability of the needle hole portions.

As a result of extensive investigations in view of the above circumstances, it has been found that when an unsintered PTFE porous sheet and a base fabric having stretching properties are bonded, the porous sheet exhibits a good follow-up property to the elongation and contraction behaviors of the base fabric, and when the base fabric elongates by the action of tension, the porous sheet elongates along the elongation thereof and the porous sheet substantially recovers its original dimensions by the removal of tension.

It has been further found that a laminated sheet in which it is difficult to cause cracks starting from the needle holes even by sewing, can be obtained by bonding a base fabric and an unsintered PTFE porous sheet having a specific elongation in two directions which are crossed and a specific breaking strength in the direction perpendicular to the surface.

Accordingly, an object of the present invention is to provide a laminated sheet having waterproofness and stretching properties.

Another object of the present invention is to provide a laminated sheet having a waterproofness and an improved sewing processability.

The laminated sheet according to the present invention comprises a base fabric having stretching properties and an unsintered PTFE porous sheet having an elongation higher than that of the base fabric.

The base fabric and the porous sheet are at least partially bonded together by, for example, adhesive.

The laminated sheet according to the present invention also comprises a base fabric and an unsintered PTFE porous sheet having desired stretching properties.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a cross-sectional view of a laminated sheet of the present invention; Figure 2 is a cross-sectional view of another laminated sheet of the present invention; Figure 3 is a cross-sectional view of the laminated sheet of Figure 1 in the stretched condition; and, Figures 4 to 6 are cross-sectional views of further laminated sheets of the present invention.

In the drawings the references indicate; 1 ... Base fabric having a stretching property; 2... Unsintered PTFE porous sheet; 3 ... Adhesive; and 4 ... Base fabric.

The base fabric having the stretching properties which can be used in one embodiment of the present invention is a knitted fabric, woven fabric or nonwoven fabric which, when tension is applied, elongates in at least one direction to a certain extent and, when the tension is removed, is released from the stretched condition and can almost recover its original dimensions.

Examples of such base fabric are fabrics or knits composed mainly of polyurethane fibers (generally called "Spandex") which are commercially available as Neoron (Teijin Ltd.), Espa (Toyobo Co., Ltd.), Mobilon (Nisshinbo Industry, Inc.), Fujibo Spandex (Fuji Spinning Co., Ltd.), Operon (Toray Ltd.), Asahika-sei Spandex (Asahikasei Textiles Ltd.) and Lycla (Du Pont).

The base fabric used in one embodiment of the present Invention has, as described above, stretching properties. The elongation of the base fabric is generally 5% or more, preferably from 10 to 100% This elongation is measured by the elongation testing method, Procedure A (a constant speed elongation method) of JIS L-1080 (clamp distance 20 cm; load 5.0 kgf). The PTFE sheet which is bonded to the base fabric having stretching properties isan unsintered porous sheet in which numerous micropores are formed by stretching or foaming and the elongation thereof is g-reater than that of the base fabric. When the base fabric has stretching properties in one direction, a porous sheet having the elongation in at least one direction greater than that of the base fabric is used.When the base fabric has stretching properties in several directions, a porous sheet having a greater elongation in each of the directions than the base fabric is used.

The base fabric having stretching properties and the porous sheet are bonded together so that the elongation of the porous sheet is greater in every direction than that of the base fabric. If the elongation of the unsintered PTFE porous sheet is smaller than that of the base fabric, when such is used by bonding to the base fabric, the- separation at the bonding portions, or breakdown of the porous sheet is undesirably caused by the action of tension.

The pore diameter of the micropores in the porous sheet is usually from about 0.01 to 20 um so as to prevent permeation of water. The thickness and porosity of the porous sheet are determined depending on the purpose for which the final laminated sheet is used. It is, however, preferred that the thickness be from about 10 to 200 Am and porosity be from about 40 to 90% so that the porous sheet can well conform to the base fabric.

The unsintered PTFE porous sheet which can be used in the present invention can be produced by various methods such as a method in which liquid lubricants are added to unsintered PTFE powders and the resulting mixture is molded into a sheet-like material by extrusion and/or rolling, and a method in which such a sheet-like material is further stretched at temperatures lower than the melting point of PTFE.

Liquid lubricants which can be used for this purpose are lubricants which can wet the surface of PTFE and can be removed by evaporation or extraction after the formation of the sheet-like material.

Examples of such liquid lubricants are hydro-carbon oils such as liquid paraffins, naphtha and white oils; aromatic hydrocarbons such as toluene and xylene; alcohols; ketones; esters; silicone oils; fluorochloro-carbon oils; solutions of polymers such as polyisobutylene and polyisoprene dissolved in the above solvents; mixtures of one or more of the above solutions; and water or aqueous solution containing surface active agents.

The amount of the liquid lubricant added is usually from about 5 to 50 parts by weight per 100 parts by weight of the PTFE powder.

It is preferred for the present invention to use a sheet obtained by biaxial stretching as such an unsintered PTFE porous sheet. For example, such a biaxially stretched sheet is obtained by simultaneously stretching in two cross directions or stretching in one direction and then stretching in the direction perpendicular thereto.

The biaxially stretched unsintered PTFE porous sheet comprises agglomerates of particles wherein the adjacent particles are entirely and/or partially bonded to each other by the external force exerted on the primary particles and/or secondary particles of PTFE during molding. The agglomerates have a number of hole-like voids. Those agglomerates together, the agglomerates and the primary particles andlor secondary particles, and the primary particles and/or secondary particles together, are joined in the form of a fibril. Those fibril-like materials are partially connected by PTFE fibrils having a cross-section smaller than the diameter of the secondary particles. Voids are present between the connected agglomerates and the connected agglomerates, the connected agglomerates and the particles, and the particles and particles.The fibrils are present in a large amount in the surface direction of sheet and a small amount in the direction perpendicular to the surface. The breaking strength in the direction perpendicular to the surface of the unsintered PTFE porous sheet is 0.1 to 1.0 kg/cm2.

The breaking strength in a direction perpendicular to the surface is measured as follows.

A pressure-sensitive double-coated adhesive tape is applied to both surfaces of a sheet, and a test piece is punched out thereof by the use of a punch having a diamter of 45 mm. This test piece is sandwiched between T-shaped jigs and bonded together under a pressure of 100 g/cm2. This is mounted on a tensile tester, and a maximum load at which the layer breaking of the test piece occurs is measured at a temperature of 25"C and a tensile speed of 10 mm/min. The breaking strength is indicated in terms of a load per unit area as calculated from the maximum load.

The biaxially stretched unsintered PTFE porous sheet having characteristics as described above exhibits particularly excellent conformability to the base fabric having stretching properties when the sheet is bonded to the sheet having stretching properties. That is, when the porous sheet elongates in one direction (x-direction) of stretching, it contracts in a direction perpendicular thereto (y-direction), whereas when the porous sheet elongates in the y-direction, it contracts in the x-direction. In those behaviors, the thickness of the porous sheet does not change, or if any, changes slightly. When the porous sheet elongates in both the x- and y- directions, the thickness of the porous sheet is reduced.However, when the tension is removed, although some wrinkles are formed temporarily in the porous sheet, the wrinkles disappear with the passage of time and the thickness of the unsintered PTFE porous sheet is returned to its original thickness.

These behaviors can be exhibited in only the biaxially stretched unsintered PTFE porous sheet having the characteristics described before.

In other words, in the structure such that adjacent particles are entirely and/or partially bonded to each other by external force exerted on the primary particles and/or secondary particles of PTFE during molding to form agglomerates having a number of voids, those agglomerates are joined to each other, the agglomerates and the primary particles and/or secondary particles are joined or the primary particles and/or secondary particles are joined to each other, in the form of a fibril, and such are partially connected by PTFE fibrils having the cross-section smaller than the diameter of the secondary particles, since each joining and connecting strength is weak, when the base fabric is elongated by external force, the porous sheet also elongates without particularly large resistance.On the other hand, even in the case that the base fabric contracts by removal of external force, the strength is weak as described above and deviation occurs between the PTFE particles in the unsintered PTFE porous sheet, and due to the deviation and also the presence of voids, the porous sheet is relatively free to contract and the force to prevent the base fabric from contracting is weak.

On the contrary, in a sintered PTFE porous sheet, agglomerates of primary particles and/or secondary particles as formed by the external force exerted during the molding are fused to each other by sintering at temperatures of the melting temperature or more of PTFE, and are united into one body. In addition, secondary particles resulting from agglomeration of primary particles are united into one body. Moreover, primary particles and/or secondary particles connected in a fibril-like form are converted into a complete fibril. As a result, the mechanical strength (excluding the tear strength) is increased and an elongation at breaking is small. The breaking strength in a direction perpendicular to the surface of the sheet is 2 kg/cm2 or more.In the case that the base fabric contracts, there is no degree of freedom in the direction of the sheet or in a direction perpendicular to the surface of the sheet. Moreover, the fibril is strong. Therefore, the conformability of the sintered PTFE porous sheet to the base fabric is greatly reduced as compared with the unsintered PTFE porous sheet. The sintered PTFE porous sheet exhibits some conformability to the base fabric when stretched slowly. However, when it is stretched in a moment, it is broken. This phenomenon is accelerated when the porous sheet is bonded.

In the present invention, it is particularly preferred to use a biaxially stretched unsintered PTFE porous sheet satisfying the following requirements: X = 20 to 300%, Y = 100 to 980%, X + Y ' 1,280% wherein X is an elongation in one direction (x-direction), and Y is an elongation in a direction (y-direction) perpendicular to the x-direction. The x-direction means the orientation direction in the PTFE sheet stretched.

The unsintered PTFE porous sheet thus biaxially stretched has an elongation in each direction, viz., the elongation in the x-direction of from about 50 to 500% and the elongation in the y-direction of from about 100 to 3,000%. This porous sheet exhibits excellent conformability to the base fabric when it is bonded thereto.

According to another embodiment of the present invention, the unsintered PTFE porous sheet having an elongation in one direction (x-direction) of 50 to 500%, an elongation in a direction (y-direction) perpendicular to the x-direction of 100 to 3,000% and a breaking strength in the direction perpendicular to the surface of 0.1 to 1.0 kg/cm2 can be bonded to a base fabric to provide a laminated sheet having an improved sewing processability. In this case, a base fabric having no stretching properties as well as the base fabric having stretching properties described above can be used.

Even if the unsintered PTFE Porous sheet having the above characteristics is bonded to the base fabric to prepare a laminated sheet and the laminated sheet is subjected to a sewing proces, cracks do not substantially occur at the needle holes formed by the penetration of sewing yarn. Further, in the sewing processed products, even if stress acts on the sewing portions during using, wearing or washing, cracks do not substantially occur at the needle holes.

If the porous sheet has the elongations and breaking strength outside the above ranges, cracks occur at the needle hole portions during sewing or during using, wearing or washing the sewed product. Thus, the improved effect of the sewing processability cannot be obtained.

It is not sufficiently clarified the reason why the laminated sheet having the above-described specific characteristics improves the sewing processability, but is is believed to be due to the following reasons.

In the structure described before, since the joining and connecting strength is weak, even if external force due to the sewing machine needle is exerted during sewing, needle holes corresponding to the diameter of the needle are easily formed without any particular resistance and cracks do not occur. Further, in the case that stress acts on the sewed portions during use of sewing processed products, deviation occurs between PTFE particles of the unsintered PTFE porous sheet, the porous sheet is free to elongate, the needle holes expand temporarily and cracks do not occur.

According to the present invention, at least one unsintered PTFE porous sheet and at least one base fabric having stretching properties or having no stretching properties are bonded.

This bonding can be carried out in various manners. For example, in one embodiment as shown in Figures 1 and 2, a base fabric 1 having stretching properties under a tension-free state and an unsintered PTFE Porous sheet 2 are partially bonded by the use of a desired adhesive 3 such as a pressure-sensitive adhesive, a hot melt adhesive or a thermosetting adhesive. This partial bonding includes a bonding in the form of dots, a bonding in the form of stripes and a bonding in the form of networks. The laminated sheet of the present invention comprises the base fabric 1 and the porous sheet 2 which are partially bonded together. If tension is applied on the laminated sheet as shown in Figure 3, for example, the base fabric 1 elongates. With the elongation of the base fabric 1, the distance between the points where the base fabric 1 and the porous sheet 2 are bonded is increased.Since the elongation of the porous sheet 2 is made to be greater than that of the base fabric 1, no breaking of the porous sheet 2 occurs. Thereafter, when the tension is removed, the base fabric 1 almost recovers its original dimensions. With the contraction of the base fabric 1, the porous sheet 2 also contracts and conforms to the base fabric 1.

In the laminated sheet as shown in Figure 1 or 2, the base fabric having stretching properties and the unsintered PTFE porous sheet are partially bonded together. Therefore, the laminated sheet has not only stretchability, waterproofness and improved sewing processability, but also air-permeability and moisture-permeability. Accordingly, the laminated sheet of the present invention is suitable as a material for use in production of clothes such as rain wear for climbing, which are often used in a perspiratory condition, or diaper covers.

Figures 4 and 5 show another embodiment of the present invention, wherein a base fabric 4 which may or may not have stretching properties,and an unsintered PTFE porous sheet 5 having specified properties,are partially bonded by the use of a desired adhesive 3 such as a pressure-sensitive adhesive, a hot melt adhesive or a thermosetting adhesive. This partial bonding includes a bonding in the form of dots, a bonding in the form of stripes and a bonding in the form of networks. The laminated sheet comprising the base fabric 4 and the unsintered PTFE porous sheet 5 which are partially bonded has not only waterproofness and improved stretching properties, but also air-permeability and moisture-permeability.Accordingly, such a laminated sheet is suitable as a material for use in production of clothese such as ski wear or rain wear, which are often used in a perspiratory condition, or diaper covers.

Figure 6 shows another embodiment of the present invention, wherein a base fabric 4 which may or may not have stretching properties and an unsintered PTFE porous sheet 5 having specified properties are bonded over the entire surface by an adhesive 3. The laminated sheet obtained by bonding the base fabric and the porous sheet over the entire surface has the advantages of an improved sewing processability, a waterproofness and a large bonding strength between the base fabric and the porous sheet.

Thus, in the present invention, the base fabric and the unsintered PTFE porous sheet may be bonded over the entire surface thereof.

As an adhesive for use in this bonding, a pressure- sensitive adhesive is suitable. Since this adhesive is capable of flowing through viscoelasticity, when the elongation of the base' fabric is relatively small or an elongation speed is relatively small, it can conform to the base fabric along with the porous sheet.

As described above, the laminated sheet according to the present invention has the structure such that the base fabric having a stretching property and the unsintered PTFE porous sheet having the conformability to the elongation and recovery of the base fabric are bonded, and has the waterproofness and stretching property as is apparent from the Examples hereinafter. Further, the laminated sheet prepared by partially bonding the base fabric and the porous sheet has the air-permeability and moisture-permeability in addition to the waterproofness and stretching property.

Further, the laminated sheet prepared by bonding a base fabric and an unsintered PTFE porous sheet having specified elongation and breaking strength in the direction perpendicular to the surface has an excellent sewing processability. Even if needle holes are formed on the porous sheet by penetration of sewing machine needle during sewing, cracks starting from the needle holes to not occur. In addition, sports wear prepared by sewing the laminated sheet according to the present invention do not cause cracks starting from the needle holes even if stress acts on the sewing portions during use. Thus, the laminated sheet according to the present invention has an excellent durability on the needle hole portions.

The present invention will now be described in greater detail by reference to the following examples and comparative examples.

Example 1 A uniform mixture of 100 parts by weight of a PTFE fine powder (trade name: Polyfuron F101; produced by Daikin Kogyo Co., Ltd.) and 26 parts by weight of a liquid lubricant, liquid paraffin, was prepared and preliminarily compression molded under a pressure of 20 kg/cm2. This molding was then extrusion molded in the form of a rod having a diameter of 20 mm and further rolled between rolling rolls to produce a long sheet-like material having a thickness of 100 Clam.

This long sheet-like material was dipped in trichloroethylene to extract and remove the liquid paraffin.

The long sheet-like material was stretched at a temperature of 50"C using a biaxial stretching apparatus so that the stretching ratio in the lengthwise direction was 100% and that in the widthwise direction was 400%,to obtain a biaxially stretched unsintered porous sheet having a thickness of 55 Fm, an average micropore diameter of 0.1 wm, the porosity of 77%, an elongation in the lengthwise and widthwise direc tions of 220% and 400%, respectively, and the breaking strength in the direction perpendicular to the surface of 0.38 kg/cm2.

A long base fabric having a stretching property (elongation in the lengthwise direction: 50%; elongation in the widthwise direction: 100%) under the tension-free state and the above-prepared unsintered PTFE porous sheet were bonded using a rubber-based pressure-sensitive adhesive in such a manner that their lengthwise directions were in agreement with each other In this bonding, the adhesive was applied in the form of dots and a pressure of 2 kg/cm2 was applied. In this manner, a long laminated sheet (Sample No. 1) was obtained. The adhesion density was 40 points per inch.

The stretching property, waterproofness and moisture-permeability of the above-prepared laminated sheet are shown in Table 1. These properties were measured as follows.

Stretching Properties (A) A test specimen (20 cm x 5 cm) was cut off of the laminated sheet. This test specimen was stretched in the lengthwise direction at a speed of 100% per minute so that the elongation in the lengthwise direction was 40% and, thereafter, the tension was removed. This operation was repeated 50 times. Then, the separation at the bonded areas, the formation of cracks in the porous sheet, and so forth were visually observed. This test was conducted for ten specimens. The rating was as follows: o No abnormality was observed.

A Abnormality was observed in several specimens.

x Abnormality was observed in all specimens.

(B) Ten specimens of the same size as above were prepared One end of each specimen was fixed, and an iron load having a weight of 2 kg was attached to the other end. Then, the specimen was dropped and it was visually observed whether or not abnormality was developed.

Waterproofness A test specimen (50 cm x 50 cm) was prepared and measured for waterproofness according to the method of JIS L-1096A. This specimen was washed in a washing machine (trade name: "Aozora" Model PF 2350, produced by Hitachi Ltd.) by a cycle of washing for 10 minutes, rinsing for 7.5 minutes, and water removal for 8.5 minutes. This cycle was repeated 100 times. Then, the waterproofness was measured according to the above-defined method.

Moisture Permeability A test specimen (50 cm x 50 cm) was prepared and measured for moisture permeability according to JIS Z-0208. This specimen was further washed in the same manner as in the above waterproofness test and then measured for the moisture permeability.

Example 2 Laminated sheets (Sample Nos. 2 to 11) were produced in the same manner as in Sample No.1 except that the stretching ratio in preparing unsintered PTFE porous sheets was changed as shown in Table 1.

The characteristics of the laminated sheets are shown in Table 1.

Example 3 A laminated sheet (Sample No.12) was produced in the same manner as in Sample No. 1 except that the base fabric having stretching properties and the unsintered PTFE porous sheet were bonded together over the entire surface.

The characteristics of the laminated sheet are shown in Table 1.

Example 4 On one surface of the same base fabric as used in Example 1 was applied a polyamide-base hot-melt adhesive (trade name: Diamide T-450, produced by Daisel Kogyo Co., Ltd.) at nearly uniform intervals so as to cover 35% of the surface area, and the adhesive was then fixed thereon by heating at 1600C for 1 minute.

The same unsintered PTFE porous sheet as used in Example 1 was superposed on the above base fabric and pressed at a temperature of 1700C under a pressure of 1 kg/cm2 for 30 minutes. In this manner, they were bonded together partially in the form of dots to produce a laminated sheet (Sample No. 13).

The characteristics of the laminated sheet are shown in Table 1.

Comparative Example 1 A biaxially stretched unsintered PTFE porous sheet was produced in the same manner as in Example 1 except that the stretching ratio in the lengthwise direction was 550% and that in the widthwise direction was 550%.

This porous sheet was sintered at 360 C for 2.5 minutes while controlling so that no dimensional variation was produced in both the lengthwise and widthwise directions, to thereby produce a sintered PTFE porous sheet. This porous sheet had the elongation in the lengthwise direction of 80%, the elongation in the widthwise direction of 120% and the breaking strength in a direction perpendicular to the surface of 2.5 kg/cm2.

A laminated sheet (Sampie No. 14) was produced in the same manner as in Sample No. 1 except that the above-prepared sintered PTFE porous sheet was used.

The characteristics of the laminated sheet are shown in Table 1.

Comparative Example 2 A biaxially stretched unsintered PTFE porous sheet was produced in the same manner as in Example 1 except that the stretching ratio was 700% in both the lengthwise and widthwise directions. This porous sheet had the elongation in the lengthwise direction of 25% and that in the widthwise direction of 55%, which were smaller than those of the base fabric having stretching properties.

A laminated sheet (Sample No. 15) was produced in the same manner as in Sample No. 1 except that the above-prepared porous sheet was used.

The characteristics of the laminated sheet are shown in Table 1.

TABLE 1 POTEE Porous Sheet Stretching Ratio Elongation" Length- Width- Length- Width wise wise wise wise Average Sample Direc- Direc- Direc- Direc- Breaking Pore No. tion tion tion tion Strength Diameter Porosit (%) (%) (%) (%) (kg/cm) ( m) (%) 1 100 400 220 400 0.38 0.1 77 2 50 150 130 850 0.96 0.07 42 3 50 900 400 130 0.28 0.2 83 4 200 200 ' 150 1,500 0.41 0.1 75 5 200 600 350 300 0.25 0.15 85 6 250 950 400 150 0;20 # 0.2 88 7 350 600 90 400 0.23 0.2 86 8 100 0 60 1,200 1.25 0.05 65 9 0 90 70 700 1.10 0.03 52 10 100 1,000 450 110 0.27 0.2 85 11 300 50 80 2,800 0.32 0.1 80 12 100 400 220 400 0.38 0.1 77 13 100 400 220 400 0.38 0.1 77 14 550 550 80 120 2.50 0.6 86 15 700 700 25 55 0.10 0.3 88 (cont'd) * According to JIS L-1080, clamp distance: 20 cm, load: 5.0 kgf TABLE 1 (Cont'd) Stretching Waerproofoess Moisture Permeability Sample ProDercies Before After Before After No. (A) (B) Washing Washing Washing Washing (cm) (ca) Cg/m2.day) Cg/m2.day) 1 o o > 200 > 200 5,000 5,000 2 o o > 200 > 200 5,000 5,000 3 0 0 > 200 > 200 5,000 5,000 4 0 0 > 200 > 200 5,000 5,000 5 0 0 > 200 > 200 6,500 6,500 6 o 0 > 200 > 200 7,000 7,000 7 o # > 200 > 200 6,500 6,500 8 o A > 200 > 200 5,000 5,000 9 o 0 A > 200 > 200 5,000 5,000 10 # # > 200 > 200 5,000 5,000 11 # # > 200 > 200 5,000 5,000 12 o å > 200 > 200 -- - 13 0 O > 200 > 200 5,000 5,000 14 h x > 200 > 200 5,000 5,000 15 x x > 200 > 200 6,000 6,000 As can be seen from the results of Table 1, the laminated sheet of the present invention can well withstand the stretching and contraction and has an excellent waterproofness. In the case that a base fabric having stretching properties and an unsintered PTFE porous sheet are partially bonded, the resulting laminated sheet exhibits good moisture permeability.

Example 5 A uniform mixture of 100 parts of weight of PTFE fine powder (trade name: Fluon CD123; produced by Asahi Fluoropolymer Co.) and 26 parts by weight of a liquid lubricant, liquid paraffin, was prepared and preliminarily compression molded under a pressure of 30 kg/cm2. This molding was extrusion molded in the form of a rod having a diameter of 20 mm and further rolled between rolling rolls to produce a long sheet-like material having a thickness of 100 i. This sheet-like material was oriented in the lengthwise direction (rolling direction).

The long sheet-like material was dipped in trichloroethylene to extract and remove the liquid paraffin.

The long sheet-like material was stretched at a temperature of 80 C using a biaxial stretching apparatus so that the stretching ratio in the lengthwise direction (x-direction) was 100% and that in the widthwise direction (y-direction) was 500% to obtain a biaxially stretched unsintered porous sheet having a thickness of 56 > , an average micropore diameter of 0.6 > , a porosity of 88%, an elongation in the lengthwise and widthwise directions of 110% and 150%, respectively, and a breaking strength in the direction perpendicular to the surface of 0.35 kg/cm2.

A long nylon tricot base fabric (trade name:Leona NYLON 66 Tricot, produced by Asahi Kasei Kogyo K.K.) comprising 30 denier and 28 gauge and having no stretching properties, and the above-prepared unsintered PTFE porous sheet were bonded using a rubber-based pressure-sensitive adhesive in the manner such that their lengthwise directions were in agreement with each other. In the bonding, the adhesive was applied in the form of dots and a pressure of 2 kg/cm2 was applied. Thus, a long laminated sheet (Sample No. 16) was obtained. The adhesion density was 35 points per inch.

The sewing processability and washing fastness of the above-prepared laminated sheet are shown in Table 2. These properties were measured as follows.

Sewing processability A test specimen (45 cm x 45 cm) was cut off of the laminated sheet. Those two specimens were partially superposed and the superposed portion was sewed with a polyester yarn of gauge 60. Formation of cracks at the needle hole portions formed on the unsintered PTFE porous sheet was visually observed.

The rating was as follows: o No crack was observed.

A Crack was observed in several specimens.

x Crack was observed in all specimens.

Washing fastness The same specimen as used in the above sewing processability test was washed in a washing machine (trade name: "Aozora Model PF2350, produced by Hitachi Ltd.) by a cycle of washing for 10 minutes, rinsing for 7.5 minutes and water removal for 8.5 minutes. This cycle was repeated until abnormality (expansion of needle holes or occurrence of cracks due to the needle holes on the needle hole portions) was observed on the surface of the PTFE porous sheet.

Example 6 Laminated sheets (Sample Nos. 17 to 23) were produced in the same manner as in Sample No.16 except that the stretching ratio in preparing unsintered PTFE porous sheets was changed as shown in Table 2.

The characteristics of the laminated sheets are shown in Table 2.

Comparative Example 3 The biaxially stretched unsintered PTFE porous sheet produced in the same manner as in Example 5 was sintered at 350OC for 2.5 minutes while controlling so that no dimensional variation was produced in both the lengthwise and widthwise directions, to thereby produce a sintered PTFE porous sheet. This porous sheet had the elongation in the lengthwise direction of 90%, the elongation in the widthwise direction of 120% and the breaking strength in a direction perpendicular to the surface of 3.1 kg/cm2.

A laminated sheet (Sample No.24) was produced in the same manner as in Sample No. 16 except that the above-prepared sintered PTFE Porous sheet was used.

The characteristics of the laminated sheet are shown in Table 2.

Comparative Example 4 Five laminated sheets (Sample Nos. 25 to 29) comprising the unsintered PTFE porous sheet and the nylon tricot were produced in the same manner as in Sample No. 16 except that the stretching ratio in preparing the unsintered PTFE porous sheet was changed as shown in Table 2.

The characteristics of those laminated sheets are shown in Table 2.

Table 2 PTFE Porous Sheet Stretching Ratio (%) Elongation* (%) Length- Width- Length- Width- Breaking Average Pore Washing Sample wise wise wise wise Strength Diameter Porosity Sewing Fastness No. Direction Direction Direction Direction (kg/cm) ( m) (%) Processability (Cycle) 16 100 500 110 150 0.35 0.6 88 # > 300 17 50 150 140 750 0.95 0.2 44 # > 300 18 50 900 370 100 0.25 0.8 83 # > 300 19 200 200 130 1300 0.40 0.5 77 # > 300 20 200 600 300 200 0.22 0.7 86 # > 300 21 250 950 330 120 0.18 0.8 89 # > 300 22 300 150 60870 0.48 0.5 75 # > 300 23 280 120 80 2800 0.30 0.6 80 # > 300 24 100 500 90 120 3.1 1.0 86 x 39 ~ 40 25 700 700 30 45 0.08 1.2 90 # 40 ~ 50 26 600 90 30 500 0.28 0.7 82 # 80 ~ 100 27 600 600 40 50 0.09 1.0 88 # 120 ~ 150 28 80 1050 360 90 0.15 0.9 89 # 50 ~ 70 29 350 40 50 3100 0.42 0.5 73 # 30 ~ 50 * Same as defined in Table 1.

It can be understood from the results shown in Table 2 that the laminated sheet according to the present invention has excellent sewing processability and washing fastness.

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.

Claims (16)

1. A laminated sheet comprising a base fabric having stretching properties, and an unsintered polytetrafluoroethylene porous sheet having an elongation larger than that of the base fabric.
2. The laminated sheet of Claim 1, wherein the base fabric and the porous sheet are partially bonded.
3. The laminated sheet of Claim 1, wherein the base fabric and the porous sheet are bonded over their entire surface.
4. The laminated sheet of Claim 1 or 2, wherein the base fabric is a knitted fabric, a woven fabric or a nonwoven fabric.
5. The laminated sheet of any preceding Claim, wherein the base fabric has an elongation of at least 5%.
6. The laminated sheet of claim 5, wherein the elongation is 10 to 100%.
7. The laminated sheet of any preceding Claim, wherein the porous sheet contains micropores having an average pore diameter of about 0.01 to 20 pm.
8. The laminated sheet of any preceding Claim, wherein the porous sheet has a thickness of about 10 to 200 calm.
9. The laminated sheet of any preceding Claim, wherein the porous sheet has a porosity of about 40 to 90%.
10. The laminated sheet of any preceding Claim, wherein the porous sheet has an elongation in one direction of 50 to 500%, an elongation in the direction perpendicular to said one direction of 100 to 3,000%, and a breaking strength in the direction perpendicular to the surface of 0.1 to 1.0 kg/cm2.
11. A laminated sheet comprising a base fabric and an unsintered polytetrafluoroethylene porous sheet, the porous sheet having an elongation in one direction of 50 to 500%, an elongation in the direction perpendicular to said one direction of 100 to 3000%, and a breaking strength in the direction perpendicular to the surface of 0.1 to 1.0 kg/cm2.
12. The laminated sheet of Claim 11, wherein the base fabric and the porous sheet are partially bonded together.
13. The laminated sheet of Claim 11, wherein the base fabric and the porous sheet are bonded together over their entire surface.
14. The laminated sheet of any of Claims 11 to 13, wherein the porous sheet contains micropores having an average pore diameter of about 0.01 to 20cm.
15. The laminated sheet of any of Claims 11 to 14, wherein the porous sheet has a thickness of about 10 to 200clam.
16. The laminated sheet of any of Claims 11 to 15, wherein the porous sheet has a porosity of about 40 to 90%.
GB08432821A 1984-03-01 1984-12-31 Laminated sheet Expired GB2155853B (en)

Priority Applications (2)

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JP4022284A JPS60183138A (en) 1984-03-01 1984-03-01 Laminated sheet
JP21569584A JPS6194752A (en) 1984-10-15 1984-10-15 Laminated sheet

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GB2155853A true GB2155853A (en) 1985-10-02
GB2155853B GB2155853B (en) 1987-06-10

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FR (1) FR2560553A1 (en)
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IT (1) IT1182185B (en)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4868928A (en) * 1987-10-21 1989-09-26 W. L. Gore & Associates, Inc. Windproof weather-resistant lined garment material
WO1990015713A1 (en) * 1989-06-16 1990-12-27 W.L. Gore & Associates, Inc. Air bag and laminates therefor and processes for making the laminates
EP0410292A2 (en) * 1989-07-24 1991-01-30 W.L. GORE &amp; ASSOCIATES, INC. Insert for lining articles of clothing
US5104727A (en) * 1989-06-16 1992-04-14 W. L. Gore & Associates, Inc. Air bag laminates
FR2690174A1 (en) * 1992-04-16 1993-10-22 Gore & Ass Soft stretch composite fabric.
FR2728280A1 (en) * 1994-12-20 1996-06-21 Kimberly Clark Co Laminated film / non-woven made compatible mechanically and article comprising such laminates
US5529830A (en) * 1994-05-25 1996-06-25 W. L. Gore & Associates, Inc. Two-way stretchable fabric laminate and articles made from it
US5882769A (en) * 1992-12-29 1999-03-16 Kimberly-Clark Worldwide, Inc. Stretch-pillowed, bulked laminate
US6139929A (en) * 1997-03-07 2000-10-31 Porvair Plc Socks
US6368609B1 (en) 1999-04-12 2002-04-09 Kimberly-Clark Worldwide, Inc. Absorbent structure including a thin, calendered airlaid composite and a process for making the composite
US6479061B2 (en) 1998-12-10 2002-11-12 Kimberly-Clark Worldwide, Inc. Absorbent structure including a thin, calendered airlaid composite and a process for making the composite
US6511927B1 (en) 1998-09-08 2003-01-28 Brookwood Companies, Inc. Breathable waterproof laminate and method for making same
WO2004108412A1 (en) * 2003-06-03 2004-12-16 Textiles Coated International Bonding unsintered non-expanded ptfe film to ptfe coated substrate
GB2470572A (en) * 2009-05-27 2010-12-01 Sealskinz Ltd A waterproof windprrof breathable and stretchable laminate

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3962153A (en) * 1970-05-21 1976-06-08 W. L. Gore & Associates, Inc. Very highly stretched polytetrafluoroethylene and process therefor
DE2737756A1 (en) * 1977-08-22 1979-03-01 Gore & Ass Laminates incorporating microporous PTFE membranes - giving waterproof and breathing properties for clothing, etc.
US4302496A (en) * 1980-10-21 1981-11-24 Albany International Corp. Composite waterproof and flame resistant fabrics

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4868928A (en) * 1987-10-21 1989-09-26 W. L. Gore & Associates, Inc. Windproof weather-resistant lined garment material
WO1990015713A1 (en) * 1989-06-16 1990-12-27 W.L. Gore & Associates, Inc. Air bag and laminates therefor and processes for making the laminates
US5104727A (en) * 1989-06-16 1992-04-14 W. L. Gore & Associates, Inc. Air bag laminates
EP0410292A2 (en) * 1989-07-24 1991-01-30 W.L. GORE &amp; ASSOCIATES, INC. Insert for lining articles of clothing
EP0410292A3 (en) * 1989-07-24 1991-10-23 W.L. Gore & Associates, Inc. Insert for lining articles of clothing
FR2690174A1 (en) * 1992-04-16 1993-10-22 Gore & Ass Soft stretch composite fabric.
WO1993021013A1 (en) * 1992-04-16 1993-10-28 W.L. Gore & Associates, Inc. Soft stretchable composite fabric
US5882769A (en) * 1992-12-29 1999-03-16 Kimberly-Clark Worldwide, Inc. Stretch-pillowed, bulked laminate
US5529830A (en) * 1994-05-25 1996-06-25 W. L. Gore & Associates, Inc. Two-way stretchable fabric laminate and articles made from it
US5804011A (en) * 1994-05-25 1998-09-08 W. L. Gore & Associates, Inc. Process of making a two-way stretchable fabric laminate and articles made from it
WO1996019349A3 (en) * 1994-12-20 1996-08-29 Kimberly Clark Co Mechanically compatibilized film/nonwoven laminates
WO1996019349A2 (en) * 1994-12-20 1996-06-27 Kimberly-Clark Worldwide, Inc. Mechanically compatibilized film/nonwoven laminates
US5837352A (en) * 1994-12-20 1998-11-17 Kimberly-Clark Worldwide, Inc. Mechanically compatibilized film/nonwoven laminate
AU699248B2 (en) * 1994-12-20 1998-11-26 Kimberly-Clark Worldwide, Inc. Mechanically compatibilized film/nonwoven laminates
FR2728280A1 (en) * 1994-12-20 1996-06-21 Kimberly Clark Co Laminated film / non-woven made compatible mechanically and article comprising such laminates
US6139929A (en) * 1997-03-07 2000-10-31 Porvair Plc Socks
US6511927B1 (en) 1998-09-08 2003-01-28 Brookwood Companies, Inc. Breathable waterproof laminate and method for making same
US6479061B2 (en) 1998-12-10 2002-11-12 Kimberly-Clark Worldwide, Inc. Absorbent structure including a thin, calendered airlaid composite and a process for making the composite
US6368609B1 (en) 1999-04-12 2002-04-09 Kimberly-Clark Worldwide, Inc. Absorbent structure including a thin, calendered airlaid composite and a process for making the composite
WO2004108412A1 (en) * 2003-06-03 2004-12-16 Textiles Coated International Bonding unsintered non-expanded ptfe film to ptfe coated substrate
US7087136B2 (en) 2003-06-03 2006-08-08 Textiles Coated International Bonding unsintered non-expanded PTFE film to PTFE coated substrate
GB2470572A (en) * 2009-05-27 2010-12-01 Sealskinz Ltd A waterproof windprrof breathable and stretchable laminate

Also Published As

Publication number Publication date
IT8547660D0 (en) 1985-02-08
GB2155853B (en) 1987-06-10
DE3503862A1 (en) 1985-09-05
GB8432821D0 (en) 1985-02-06
IT1182185B (en) 1987-09-30
FR2560553A1 (en) 1985-09-06

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