GB1600745A

GB1600745A - Sheet material

Info

Publication number: GB1600745A
Application number: GB20388/77A
Authority: GB
Original assignee: British United Shoe Machinery Ltd
Current assignee: Noxet UK Ltd
Priority date: 1978-05-15
Filing date: 1978-05-15
Publication date: 1981-10-21

Description

(54) IMPROVEMENTS IN OR RELATING TO SHEET MATERIAL (71) We, THE BRITISH UNITED SHOE MACHINERY COMPANY LIMITED, a British Company, of Union Works, Belgrave Road, in the City of Leicester, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention is concerned with improvements in or relating to sheet material especially sheet material in which at least one surface may be subjected to abrasion during use. For example, many materials used in the manufacture of shoes, when incorporated in a shoe are subjected to abrasion by the foot in the course of wear, e.g. shoe insoles, shoe heel end stiffeners and shoe lining materials. It has been proposed to manufacture such sheet materials of non-woven bonded fibre fabrics. For example, in our Patent No. 1333217 the manufacture of a non-woven bonded fibre fabric shoe insole material is described. While this has proved to be a satisfactory insole material in many types of shoes, for use in footwear in which no sock is incorporated the foot contacting surface of the insole material has, in wear, tended to be abraded more readily than is desirable. Furthermore, the appearance of the material surface has not been acceptable for incorporation in some types of shoe.

The invention provides sheet material suitable for use in the manufacture of shoes comprising a non-woven bonded textile fibre fabric and a net of thermoplastics material adhered thereto to provide a wear-resistant and decorative surface on the non-woven fabric.

The invention also provides a shoe insole comprising a non-woven bonded textile fibre fabric layer having a net of thermoplastics material adhered thereto to provide a wear-resistant and decorative surface on the non-woven layer.

The invention further provides a method of making sheet material comprising procuring a non-woven bonded textile fibre fabric, bringing a net of thermoplastics material into contact with the surface of the fabric, feeding the fabric and net assembly between pressing members, at least one of which is heated, by which the fabric and net are subjected to heat and pressure sufficiently to soften the net to adhere it to the fabric, and cooling, or allowing to cool, the fabric and the net adhered thereto, the net providing a wear-resistant and decorative surface on the non-woven fabric.

The invention also provides a sheet material made by a method as set out in the last preceding paragraph.

In selecting a net of thermoplastics material for use in carrying out a method in accordance with the invention care must be exercised in selecting a net of material having suitable properties. The softening point of the thermoplastics material should be such that the net softens, in carrying out a method in accordance with the invention, sufficiently to adhere to the textile fibre fabric at a temperature sufficiently low that the fabric is not damaged but at a sufficiently high temperature that the thermoplastics material does not soften during use of the sheet material. For use as a shoe insole polyolefin nets have been found satisfactory, preferably low density polyethylene.

In sheet material in accordance with the invention the thermoplastics material adhered to the surface of the non-woven fabric, is preferably such that in a standard abrasion test (as hereinafter set out) the weight loss of the sheet material subjected to the test is not more than 70% of the weight loss which arises in a similar test on the non-woven bonded textile fibre fabric alone.

Preferably the weight loss of sheet material in accordance with the invention in the test referred to is not more than 50% and more preferably not more than 30% of the weight loss in a similar test on the non-woven bonded textile fibre fabric alone.

The term "standard abrasion test" where used herein is to be understood as denoting an abrasion test using a Satra Martindale Abrasion machine (available from The Shoe and Allied Trades Research Association, Satra House, Rockingham Road, Kettering, Northants) as described in "Test Method PM 31, Satra Equipment Instructions STM 105M.

The Satra Martindale Abrasion Machine for Upper Materials", dated July 1970 except for the following differences. The standard abrasion test is a wet abrasion test. Top and bottom pads for the Satra Martindale Abrasion Machine are immersed in an aqueous solution consisting of 1% of the setting agent Teepol (Teepol is a Trade Mark) until thoroughly soaked. Two of the soaked top pads are then placed in surface contact and passed between stripper rollers set at a 15 thou gap and one of the pads is then positioned in the machine.

One soaked bottom pad is then passed between stripper rollers set at a 25 thou gap and positioned in the machine. The test piece of sheet material, having first been weighed, is also positioned in the machine. After 300 cycles of the machine the pads are re-wet with 5 cc 1% Teepol solution and after 600 cycles again re-wet with 3 cc of 1% Teepol solution. After 800 cycles the standard abrasion test is complete and the test piece is removed from the machine and again weighed. The % weight loss is then calculated: %weight loss = x Y x 100 x (100) x (38) where x is the initial weight of the test piece and y is the final weight. The factor (100)/(38) is included since only 38% of the area of the test piece is exposed to wear.

In sheet material in accordance with the invention the thermoplastics material adhered to the surface of the non-woven fabric is preferably such that in a standard abrasion test (as herein set out) the weight loss of the sheet material subjected to the test is less than 3% and the non-woven bonded textile fibre fabric is preferably such that in a similar test on the fabric alone the weight loss of the fabric subjected to the test is greater than 3%.

In sheet material in accordance with the invention the thermoplastics material adhered to the surface of the non-woven fabric is preferably such that in a standard abrasion test (as herein set out) the decrease in thickness of the material subjected to the test is less than 1% and the non-woven bonded textile fibre fabric is preferably such that in a similar test on the fabric alone the decrease in thickness of the fabric subjected to the test is more than 1%.

Preferably the net selected is such that the decrease in thickness of the sheet material subjected to the test is zero, or substantially so. Non-woven bonded textile fibre fabrics suitable for use in shoe insoles when subjected to the test commonly exhibit a decrease in thickness of substantially more than 1% e.g. 5% or even more.

Where sheet material in accordance with the invention is to be used for a purpose in which it is important to retain porosity and moisture absorbent properties of the non-woven bonded textile fibre fabric then it is important to select a net in which the holes form a suitable proportion of the total net area. For example, where sheet material in accordance with the invention is to be used in the manufacture of shoe insoles, the holes of the net should not be too small (otherwise the chance of the net fusing together to make an impermeable film, thereby destroying the porosity and water absorbency which is a useful feature of this type of insole, would be too great) and neither should the holes be too big (because this would permit abrading of too great an area of the non-woven fabric causing "pilling" - the formation of small hard balls of fibre on the foot-contacting surface of the material). For example, conveniently the holes of a net used in carrying out a method in accordance with the invention may comprise between 25% and 60% of the total area of the net depending to some extent on the size of the holes and weight of the net.

Where the material is for use as a shoe insole the net bonded to the surface of a non-woven textile fibre fabric base is selected to give an appearance pleasing to the eye, suitable for use as an insole in shoes where no sock lining is to be employed. The decorative pattern on the surface of the insole may be varied by selecting a different net pattern. The net should not be too bulky, otherwise discomfort may be caused to the foot of a wearer of a shoe in which sheet shoe insole material in accordance with the invention comes to be incorporated; conveniently the net used weighs between 30 and 70 glum2.

A non-woven bonded textile fibre fabric used in the invention may comprise any suitable textile fibres. However, where the sheet material in accordance with the invention is to be used as a shoe insole material the fibres are preferably not less than 20% by weight nylon more preferably at least 33% by weight nylon, with other synthetic fibres forming the remainder. Conveniently the remainder of the fibres may mostly be acrylic fibres.

Preferably where the sheet material is for use as a shoe insole no viscose rayon fibres are used as these tend to have an undesirable effect on the dimensional stability of the sheet material and wet strength (tensile).

The bonding agent used in the non-woven bonded textile fibre fabric for use in the invention may be one of the commonly used bonding agents, for example styrene-butadiene polymer, butadiene-acrylonitrile polymer, and vinylchloride polyer, acrylic polymers and the like. Conveniently where the sheet material is for use as a shoe insole material the bonding agent may be polystyrene e.g. comprising a styrene homopolymer and a styrene-butadiene polymer having a high styrene content.

Conveniently in sheet shoe insole material in accordance with the invention the ratio of bonding agent to fibre in the non-woven bonded textile fibre fabric is about 1:1 by weight.

Suitably the bonding agent content, by weight, of the fabric is not less than 40% and not greater than 60%. Conveniently in sheet shoe insole material in accordance with the invention the bonded textile fibre fabric is between 700 and 1500 g/m2 in weight and the lower weights being for thinner material and higher weights for thicker material, thickness being between 1.5 and 3mm.

In carrying out a method in accordance with the invention, the net in contact with the textile fibre fabric is subjected to heat and pressure applied by two pressing members.

Conveniently, for example, one of the pressing members is a heated drum and the other is a tensioned continuous belt which is wrapped round a considerable part of the circumference of the drum, the continuous belt passing round rolls and being driven at a surface speed the same as the speed of movement of the drum surface. Preferably one of the rolls around which the tensioned belt passes is urged towards the drum surface with a considerable pressure thus forming a "nip" between this roll and the drum surface. The net and textile fibre fabric are brought into contact and pressed together initially by this "nip" and maintained under pressure whilst the assembly passes round the drum. In this system the drum is heated to a temperature sufficient to soften the net to cause it to adhere to the textile fibre fabric.

There now follows a detailed description, hereinafter set out as Examples 1 to 4, of sheet shoe insole materials and their method of manufacture. It will be realised that the materials and the methods hereinafter set out have been selected for description to illustrate the invention by way of example and not of limitation of the invention.

In the drawings accompanying the provisional specfication: Figure 1 shows apparatus used in carrying out the illustrative methods hereinafter described, in operation; Figure 2 is a diagrammatic plan view of net used in Examples 1 and 3; and Figure 3 is a diagrammatic plan view of net used in Exampes 2 and 4.

Example 1 A non-woven bonded textile fibre fabric is first made, in carrying out the first illustrative method, for example generally as described by way of example in our patent specification No. 1333217. Textile fibres are first formed into a fibre batt by known non-woven batt-manufacturing technqiues, for example including crosslapping and needling, as described in patent specification No. 133217. The non-woven fibre batt is then impregnated with an aqueous dispersion of a suitable binding agent and passed between stripper rolls to control the amount of impregnant taken up. The impregnated non-woven fibre batt is then dried to remove the water thereby providing a non-woven bonded textile fibre fabric.

The fibres used in preparing the fibre fabric in carrying out the first illustrative method comprise one part by weight nylon 6, one part by weight spinning waste (mainly acrylic fibres but with a small quantity of other fibres, e.g. polyester and nylon fibres), and one part by weight of mixed synthetic fibres, the precise composition of which may be variable and the fibres in which may include, for example, acrylic, nylon and polyester fibres in varying proportions. The impregnant used is an aqueous dispersion comprising as binding agent styrene polymers, namely 60 parts by weight of a styrene homopolymer dispersion and 40 parts by weight of a styrene-butadiene copolymer dispersion comprising 88% styrene and 12% butadiene mixed in such proportions that the total butadiene content by weight of solids in the impregnant is about 4.6%. The dried impregnated batt provides a fabric comprising approximately 56% by weight fibres and 44% by weight bonding agent, has a weight of about 950 g/m2 and is slightly over 2 mm thick.

The non-woven bonded textile fibre fabric is then laminated with the thermoplastics net using the apparatus shown in Figure 1 of the drawings. The apparatus comprises a drum 2 mounted for rotation about a central axis 4. A continuous belt 6 having a non-stick surface is wrapped around about three-quarters of the periphery of the drum 2. The belt is guided by a number of rollers 8, 10, the position of certain of which rollers can be adjusted to adjust the tension on the belt and thereby adjust the pressure with which the belt 6 bears against the surface of the drum 2. The roll 8 is mounted for movement radially towards and away from the axis 4 so that a nip may be formed between the roll 8 and the surface of the drum 2; the pressure with which the roll 8 bears against the surface of the drum 2 may be adjusted. Means, for example steam conduits, are provided for heating the drum 2.

In carrying out the first illustrative method, the drum 2 is caused to rotate and the belt 6 is caused to travel at a speed such that the run of the belt in contact with the surface of the drum 2 moves at the same speed as the drum surface, without slipping on the surface. The heating means of the drum 2 heats the drum so that its surface temperature is 140"C. A sheet 16 of the non-woven bonded textile fibre fabric made as hereinbefore described is fed, in contact with a sheet 14 of a thermoplastics net, into the nip between the roll 8 and the surface of the drum 2; the sheets 14, 16 are sandwiched between two sheets 12 of silicone coated release paper, with the sheet 14 of net lying closer to the surface of the drum 2 than the sheet 16 of fabric. The sheets 12, 14, 16 are conveniently fed from rolls (not shown).

In carrying out the first illustrative method the sheet 14 of thermoplastics net is a low density polyethylene net weighing about 40 glum2 designated Q225 and available from the firm Smith & Nephew Plastics Ltd; the net is white in colour. The Q225 net is shown in Figure 2 and is made in such a way that about 47% of the total area of the net is occupied by holes which have approximately, the shape of a rhombus in which the distance AC between one opposed pair of apices is about 0.11 inch and the distance BD between the other opposed pair of apices is about 0.07 inch.

In carrying out the first illustrative method, the roll 8 is urged towards the surface of the drum 2 with such a force that it exerts a pressure of about 20 Ibs. per square inch on the sheets passing through the nip. The tension of the belt 6 is such that a pressure of about 0.75 Ibis. per square inch is exerted on the sheets 14, 16 by the belt 6 as the materials travel round the drum. The sheets 12, 14, 16 are contiguous with the surface of the drum 2 for about 45 seconds.

On leaving the drum the net is allowed to cool and the sheets 12 of release paper are separated from the sheet 16 of fabric with the sheet 14 of net firmly adhered to the surface of the fabric; the sheet 16 of fabric with the sheet 14 of net adhered to the surface thereof provides the first illustrative sheet shoe insole material.

Insoles may be cut out of this first illustrative shoe insole material and incorporated in a shoe during the course of manufacture thereof, in known manner, with the net-coated surface forming the foot-contacting surface of the insole. The net on the surface gives a wear-resistant surface and the pattern of the applied net is pleasing to the eye so that the surface as well as being wear resistant is also decorative and has aesthetic appeal.

In the standard abrasion test hereinbefore set out there was a weight loss from the abraded net-coated surface of 2.7% and a zero change in thickness. For comparison when a sample of the non-woven bonded textile fibre fabric without the net layer adhered thereto was subjected to a similar test the percentage weight loss was 9.1 and there was a 6% decrease in the thickness of the material, The fibres used in the manufacture of the non-woven bonded textile fibre batt are of various colours and the net provides an improved surface appearance over the uncovered fabric.

Example 2 The second illustrative method of making a second illustrative sheet shoe insole material is similar to the first method in every respect except for the thermoplastics net used. In carrying out the second illustrative method the thermoplastics net used. In carrying out the second illustrative method the thermoplastics net used is a black high density polyethylene net made by Smith & Nephew Plastics Ltd., weighing approximately 50 g/m2 and designated X115. The holes in this black net are larger than those in Q225 net of the first Example, and the areas of plastics material are also correspondingly larger. The X115 net is shown in Figure 3 and is made in such a way that about 36% of the total area of the net is occupied by holes which have the shape, approximately, of an isosceles triangle in which the base FG is about 0.115 inch long and the height from the apex E to the base FG is about 0.15 inch.

The second illustrative sheet material is similar in wear characteristics to the first illustrative material and gives identical results in the standard abrasion test. The second illustrative sheet material in which the wear-surface is provided by the black X115 net has, however, a bolder surface pattern.

Example 3 In carrying out a third illustrative method a non-woven bonded textile fibre fabric is made in a similar manner to that described in Example 1 but the fibre content of the fabric is somewhat different. The fibre batt used in the third illustrative method comprises one part by weight nylon 6 fibres, one part by weight of fibres which are a mixture of nylon 6 and triacetate (approximately 15% nylon and 85% triacetate) and one part by weight of acrylic fibres spinning waste.

In carrying out the third illustrative method the non-woven textile fibre batt described above is impregnated with the same impregnant as is used in Example 1 above and dried to provide a bonded fabric comprising approximately 45% by weight fibres and 55% by weight bonding agent, having a weight of about 950 g/m2 and a thickness of slightly over 2 mm. The fabric is laminated, under the conditions set out in Example 1, with the Q225 thermoplastics net described in Example 1.

The fibres used in the non-woven textile fibre batt are all white and the appearance of the finished, third illustrative sheet shoe insole material is more uniform, although the thermoplastics net still provides a clearly discernible decorative pattern on the surface.

When the third illustrative sheet material was subjected to the standard abrasion test (abrading the surface on which the thermoplastics net is bonded) a weight loss of 2.2% occurred but there was no loss in thickness of the material. For comparison the non-woven bonded textile fibre fabric without the net adhered thereto was-subjected to the same wet abrasion test: a 3.8% weight loss occurred but there was a 5% decrease in thickness of the material.

Example 4 In carrying out the fourth illustrative method a non-woven textile fibre fabric made as set out in Example 3 was laminated with the black X115 thermoplastics net described in Example 2, using the same laminating conditions.

The material made by carrying out the fourth illustrative method was the fourth illustrative sheet shoe insole material. This fourth illustrative material was subjected to the standard abrasion test and a 2.5% weight loss occurred, although there was no loss in thickness of the fourth illustrative material.

All four illustrative materials had adequate flex properties, tensile strength, abrasion resistance and retained satisfactory water absorbency for use as a shoe insole. The four illustrative materials retained their decorative surface appearance for a satisfactory length of time in wear in a shoe and it was found that little or no "pilling" occurred in wear thus retaining a smooth foot-contacting surface which caused no discomfort to the wearer of the shoe.

WHAT WE CLAIM IS: 1. Sheet material suitable for use in the manufacture of shoes comprising a non-woven bonded textile fibre fabric and a net of thermoplastics material adhered thereto to provide a wear-resistant and decorative surface on the non-woven fabric.

2. A shoe insole comprising a non-woven bonded textile fibre fabric layer having a net of thermoplastics material adhered thereto to provide a wear-resistant and decorative surface on the non-woven layer.

3. Sheet material according to claim 1 wherein the fibres of the non-woven bonded textile fibre fabric comprise not less than 20% by weight of nylon fibres.

4. Sheet material according to claim 3 wherein the fibres comprise at least 33% by weight of nylon fibres.

5. Sheet material according to any one of claims 1, 3 and 4 wherein the non-woven bonded textile fibre fabric comprises polystyrene bonding agent.

6. Sheet material according to any one of claims 1 and 3 to 5 wherein the non-woven bonded textile fibre fabric comprises not less than 40% and not more than 60% by weight, of bonding agent.

7. Sheet material according to any one of claims 1 and 3 to 6 wherein the thermoplastics material of the net is polyolefin.

8. Sheet material according to claim 7 wherein the polyolefin is polyethylene.

9. Material according to any one of claims 1 and 3 to 8 wherein the non-woven bonded textile fibre fabric weighs between 700 and 1500 g/m2.

10. Material according to any one of claims 1 and 3 to 9 wherein the non-woven bonded textile fibre fabric is between 1.5 and 3 mm thick.

11. Material according to any one of claims 1 and 3 to 10 wherein the net weighs between 30 and 70 g/m2.

12. A method of making sheet material comprising procuring a non-woven bonded textile fibre fabric, bringing a net of thermoplastics material into contact with the surface of the fabric, feeding the fabric and net assembly between pressing members, at least one of which is heated, by which the fabric and net are subjected to heat and pressure sufficiently to soften the net to adhere it to the fabric, and cooling, or allowing to cool, the fabric and the net adhered thereto, the net providing a wear-resistant and decorative surface on the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. somewhat different. The fibre batt used in the third illustrative method comprises one part by weight nylon 6 fibres, one part by weight of fibres which are a mixture of nylon 6 and triacetate (approximately 15% nylon and 85% triacetate) and one part by weight of acrylic fibres spinning waste. In carrying out the third illustrative method the non-woven textile fibre batt described above is impregnated with the same impregnant as is used in Example 1 above and dried to provide a bonded fabric comprising approximately 45% by weight fibres and 55% by weight bonding agent, having a weight of about 950 g/m2 and a thickness of slightly over 2 mm. The fabric is laminated, under the conditions set out in Example 1, with the Q225 thermoplastics net described in Example 1. The fibres used in the non-woven textile fibre batt are all white and the appearance of the finished, third illustrative sheet shoe insole material is more uniform, although the thermoplastics net still provides a clearly discernible decorative pattern on the surface. When the third illustrative sheet material was subjected to the standard abrasion test (abrading the surface on which the thermoplastics net is bonded) a weight loss of 2.2% occurred but there was no loss in thickness of the material. For comparison the non-woven bonded textile fibre fabric without the net adhered thereto was-subjected to the same wet abrasion test: a 3.8% weight loss occurred but there was a 5% decrease in thickness of the material. Example 4 In carrying out the fourth illustrative method a non-woven textile fibre fabric made as set out in Example 3 was laminated with the black X115 thermoplastics net described in Example 2, using the same laminating conditions. The material made by carrying out the fourth illustrative method was the fourth illustrative sheet shoe insole material. This fourth illustrative material was subjected to the standard abrasion test and a 2.5% weight loss occurred, although there was no loss in thickness of the fourth illustrative material. All four illustrative materials had adequate flex properties, tensile strength, abrasion resistance and retained satisfactory water absorbency for use as a shoe insole. The four illustrative materials retained their decorative surface appearance for a satisfactory length of time in wear in a shoe and it was found that little or no "pilling" occurred in wear thus retaining a smooth foot-contacting surface which caused no discomfort to the wearer of the shoe. WHAT WE CLAIM IS:

1. Sheet material suitable for use in the manufacture of shoes comprising a non-woven bonded textile fibre fabric and a net of thermoplastics material adhered thereto to provide a wear-resistant and decorative surface on the non-woven fabric.

8. Sheet material according to claim 7 wherein the polyolefin is polyethylene.

non-woven fabric.

13. A method according to claim 12 wherein the holes of the net comprise between 25% and 60% of the total area of the net.

14. A method according to either one of claims 12 and 13 wherein the non-woven bonded textile fibre fabric weighs between 700 and 1500 g/m2.

15. A method according to any one of claims 12 to 14 wherein the non-woven bonded textile fibre fabric is between 1.5 and 3 mm thick.

16. A method according to any one of claims 12 to 15 wherein the net weighs between 30 and 70 g/m2.

17. A method according to any one of claims 12 to 16 wherein the fibres of the non-woven bonded textile fibre fabric comprise not less than 20% by weight nylon fibres.

18. A method according to claim 17 wherein the fibres comprise at least 33% by weight nylon fibres.

19. A method according to any one of claims 12 to 18 wherein the non-woven bonded textile fibre fabric comprises polystyrene bonding agent.

20. A method according to any one of claims 12 to 19 wherein the non-woven bonded textile fibre fabric comprises not less than 40% and not more than 60% by weight, of bonding agent.

21. A method according to any one of claims 12 to 20 wherein the thermoplastics material of the net is polyolefin.

22. A method according to claim 21 wherein the polyolefin is polyethylene.

23. A method according to any one of claims 12 to 22 wherein one of the pressing members is a drum and the other is a tensioned continuous belt wrapped round a considerable part of the circumference of the drum and being driven at a surface speed the same as the speed of movement of the drum surface.

24. A method according to claim 23 wherein pressure is applied to the assembly by a roll urged towards the drum surface.

25. A method of making sheet material substantially as hereinbefore described with reference to any one of the Examples.

26. Sheet material made by a method according to any one of claims 12 to 25.

27. A shoe insole comprising sheet material according to any one of claims 1, 3 to 11 and 26.