AU6842200A

AU6842200A - Heel lining for use in the shoe industry

Info

Publication number: AU6842200A
Application number: AU68422/00A
Authority: AU
Inventors: Robert Groten; Rudolf Wagner
Original assignee: Carl Freudenberg KG
Current assignee: Carl Freudenberg KG
Priority date: 1999-10-05
Filing date: 2000-09-01
Publication date: 2001-05-10
Anticipated expiration: 2020-09-01
Also published as: JP2003511567A; NO20021477L; AU769920B2; SK4592002A3; ATE281553T1; CN1377434A; DE50008538D1; NO20021477D0; CZ20021122A3; CN1164829C; EP1224355B1; EE200200166A; CA2386389A1; EP1224355A1; BG106565A; ZA200202648B; DE19947870C1; WO2001025529A1; BR0014542A; RU2225699C2

Abstract

The invention relates to a heel lining for use in the shoe industry comprising a polymer impregnated non-woven having a surface area weight of 180 to 350 g/m<2> and a tear strength of > 15 N in a longitudinal and a perpendicular direction. The non-woven consists of melt spun, aerodynamically stretched multi-component endless filaments which are arranged directly to form a non-woven. Said non-woven has a titer of < 2 dtex. The multi-component endless filaments are split and hardened when said filaments have attained a pre-defined strength of 90 % of the supermicro-endless filaments, i.e. a titer of < 0.2 dtex.

Description

WO 01/25529 PCT/EPOO/08547 Heel lining for the shoe industry Description The invention relates to a heel lining for the shoe industry as well as a method for producing said heel lining. In the shoe industry particularly abrasion-resistant materials are used for the rear part of a shoe, the so-called heel cap. These materials are intended to absorb the forces which act on the shoe as a result of foot movement, in particular during roll movement in longitudinal direction. Said materials must also withstand the friction forces which during walking are caused by the foot at least partially moving up and down in the shoe. To prevent unintended slipping of the foot out of the shoe during the roll movement, traditionally a hunting-calf like or suede-like material is used as a heel lining, said material, as a result of friction engagement with the wearer's foot or the sock or stocking, preventing the foot from slipping out of the shoe. Apart from heel linings made from natural materials, heel linings from synthetic materials are also used. Such synthetic materials include needle-punched nonwoven fabrics which are produced in a dry process by combing, from polyester, viscose, polyamide, polypropylene fibres or from mixtures of these fibres. Fibrous webs with a mass per unit area of up to 800 g/m 2 are used which are mechanically bonded by intensive needle-punching. This process step in itself is already very time-consuming and thus relatively expensive. Said process step is usually followed by shrinking the needle-punched nonwoven fabric by means of hot air or steam which leads to bonding and further strengthening of the material as far as setting the desired density for the application purpose is concerned. In order to achieve the necessary strength parameters, such as resistance to tearing and to further tearing of the needle punched nonwoven fabric, said fabric is impregnated with a heat coagulable latex binder dispersant such as styrene butadiene rubber (SBR) or nitrile butadiene rubber (NBR) and subsequently dried. The latex content is approx.

-2 30 to 60 % by weight of the weight of the impregnated nonwoven fabric. The material prepared in this way is split into two to four thinner layers. This splitting process for nonwoven fabrics has been taken over from the leather industry so as to increase productivity in the production of nonwoven fabrics. These split products can additionally be ground so as to even out their surface and improve their appearance. Finally, a melting adhesive is applied to one of the two sides so as to facilitate further processing. Synthetic heel lining material used up to now has been associated with disadvantages, above all the very varying strength values in longitudinal direction and in transverse direction; the loss of strength resulting from splitting the fibrous bundles arranged perpendicular as a result of needle-punching; as well as irregularities in the individual layers due to inward and outward needle penetration. It is the object of the present invention to disclose a heel lining for the shoe industry which heel lining at mass per unit areas of 180 to 350 g/m 2 achieves a tear and tear propagation resistance of > 15 N both in longitudinal and in transverse direction. It is a further object of the present invention to disclose a method that is particularly suitable for producing such a heel lining. According to the invention, this object is met by a heel lining comprising a polymer-impregnated nonwoven fabric with a mass per unit area of 180 to 350 g/m 2 and a tear and tear propagation resistance of > 15 N both in longitudinal and in transverse direction, wherein the nonwoven fabric comprises melt-spun aerodynamically stretched multi-component continuous filaments which are immediately laid down to form a nonwoven fabric, with a titre of < 2 dtex, and wherein, after pre bonding, at least 90 % of the multi-component continuous filaments are split and bonded to form supermicro continuous filaments with a titre of < 0.2 dtex. Such heel lining material has very good tensile strength and abrasion resistance at less mass per unit area. Preferably, the heel lining is a heel lining in which the multi-component continuous filament is a bi-component continuous filament made of two incompatible polymers, in particular a polyester and a polyamide. In this way, the multi-component continuous filament is easy to split and has a very good ratio of strength to mass per unit area.

-3 Preferably, the heel lining is a heel lining in which the polyester fraction in the multi-component continuous filament exceeds the polyamide fraction, in particular in the weight ratio of polyester fraction to polyamide fraction ranges from 1.1 : 1, to 3 : 1. In this way, the heel lining has a very textile-like handle and good resistance to ageing. Particularly preferred is a heel lining in which the cross-section of the multi component continuous filaments is of orange-like multi segment structure, wherein the segments alternately comprise one of the two incompatible polymers. Preferably, the heel lining is a heel lining in which the nonwoven fabric formed from the multi-component continuous filaments is pre-calendered for pre bonding. In this way, the material is of very even thickness. Furthermore, particularly preferred is a heel lining in which at least one of the incompatible polymers which form the multi-component continuous filament, comprises an additive such as dyestuff pigments, permanently acting antistatic agents and/or additives having an influence on the hydrophilic or hydrophobic properties in quantities up to 15 % by weight. In this way, the heel lining can be positively influenced in relation to its fastness to light, its inclination to static charging, its perspiration dissipation or its moisture banking-up effect. Furthermore, the addition of dyestuff pigments to the spinning mass makes it possible to produce deeper and more abrasion-resistant colours. Furthermore, particularly preferred is a heel lining in which the multi-component continuous filament is non-crimped because in this way the textile handle resulting from the good splitability into supermicro continuous filaments is ensured. Particularly preferred according to the intention is a heel lining in which the nonwoven fabric is impregnated with a polymer at 20 to 50 % by weight of the initial weight of the nonwoven fabric. With comparable impregnation rates, the heel lining has superior strength properties compared to known synthetic heel lining materials.

-4 Preferably, the heel lining is a heal lining in which one side comprises an application of a melting adhesive. Such a material is in particular suitable for further processing on automatic machines. The method according to the invention for producing the heel lining consists of the multi-component continuous filaments being spun from the melt, being aerodynamically stretched and immediately laid down to form a nonwoven fabric, with pre-bonding by way of pre-calendering or needle-punching taking place and with the nonwoven fabric being bonded by means of high-pressure fluid jets as well as at the same time being split into supermicro continuous filaments with a titre of < 0.2 dtex and subsequently being impregnated with a polymer. The products obtained in this way are very even from the point of view of their strength properties, because the yarn distribution in the product is to a large extent isotropic. The products show no tendency to delaminate and they display good module values as well as tear resistance and tear propagation resistance. In a further advantageous embodiment of the method, bonding and splitting of the multi-component continuous filaments takes place in that the pre-bonded nonwoven fabric is subjected to treatment from high-pressure water jets, alternately from both sides. This type of bonding and splitting of the multi component continuous filaments results in very dense nonwoven fabrics with smooth surfaces. Preferably, bonding and splitting of the multi-component continuous filament is carried out on a unit with rotary screen drums. This type of unit design makes it possible to construct very compact plants. It is particularly preferred if impregnation of the nonwoven fabric which has predominantly been split into supermicro continuous filaments and has been bonded, takes place by means of an aqueous polyurethane latex dispersant or an NBR latex dispersant. In this way, there are no solvent residues and impregnation with a polymer is undertaken in a particularly environmentally friendly way. Preferably, the impregnated material is subjected to follow-up treatment by abrading or velour-finishing. These measures can still further improve the -5 surface properties and the handle of the material obtained. As a result of the micro filaments contained in the structure, a particularly fine Nubuck-like surface is achieved which is very similar to that of natural leather. Example The titre of initial filaments is approx. 1.8 dtex, with the filaments comprising 16 segments, wherein polyester segments alternate with polyamide segments, like orange segments, around a central axis. The melt-spun multi-component continuous filaments are aerodynamically stretched and laid down on a belt. The fibrous fabric obtained in this way is subjected to pre-calendering at a temperature of approx. 95 *C and a pressure of approx. 100 bar. Mechanical pre-bonding by needle-punching is followed by water jet treatment with the water pressure being approx. 100 bar. Subsequently, the multi-component continuous filaments are split into supermicro continuous filaments with a titre of approx. 0.1 dtex and then the fibrous web is bonded. Treatment occurs twice from each side at a water pressure of between 250 and 300 bar and on screen backings of 60 to 100 mesh width. The nonwoven fabric is then dried and subjected to impregnation with polymer by means of a dry-in-wet treatment with NBR latex. Approx. 125 weight % of NBR relative to the initial weight of the nonwoven fabric is applied and fixed by drying at 180 0C. Following grinding, a heel lining with a weight of 260 g/m 2 and a thickness of 0.75 mm is obtained. Comparison example By way of intensive needle-punching, a nonwoven fabric is produced from polyester staple fibres and polypropylene staple fibres, with said nonwoven fabric being impregnated with NBR. By way of splitting, a heel lining with a mass per unit area of 320 g/m 2 and a thickness of 0.85 mm is obtained. Table 1 below shows a comparison of strength values and abrasion resistance. Abrasion resistance was determined by fixing a test body of 90 mm 0 which was clamped in a rotary grip head and loaded with a scouring pressure of 2.8 N/cm 2 . The rotary angle of the grip head was 50 degrees. The test specimen was tested by subjecting it to contact with a scouring element whose surface comprised lozenge shapes. The test specimen was wetted with water and -6 subjected to cyclical to-and-fro movements, with each scouring cycle comprising 300 to-and-fro movements. This was followed by visual assessment based on a model wherein assessment marks were obtained. Example Comparison example Weight g/m2 320 Ihickness mm 0.75 0.85 Surface Mark 1.0 1.0 10 % module longitudinally N /5cm 220 310 10 % module transversely N/5cm 160 85 Tear propagation force longitudinally N 21 10 T ear propagation force transversely N 21 10 Abrasion (according to WN 3147/1) Mark 1.0 1.0- 1.5 Table 1

Claims

1. A heel lining for the shoe industry which heel lining at mass per unit areas of 180 to 350 g/m 2 achieves a tear propagation resistance of > 15 N both in longitudinal and in transverse direction, wherein the nonwoven fabric comprises melt-spun aerodynamically stretched multi component continuous filaments, immediately laid down to form a nonwoven fabric, with a titre of < 2 dtex, and wherein, after pre bonding, at least 90 % of the multi-component continuous filaments are split and bonded to form supermicro continuous filaments with a titre of < 0.2 dtex.

2. The heel lining according to claim 1, in which the multi-component continuous filament is a bi-component continuous filament made of two incompatible polymers, in particular a polyester and a polyamide.

3. The heel lining according to claim 2, in which the polyester fraction in the multi-component continuous filament exceeds the polyamide fraction.

4. The heel lining according to claim 3, in which the weight ratio of polyester fraction to polyamide fraction in the multi-component continuous filament ranges from 1.1 : 1, to 3 : 1.

5. The heel lining according to one of claims 1 to 4, in which the cross section of the multi-component continuous filaments is of orange-like multi segment structure, wherein the segments alternately comprise one of the two incompatible polymers.

6. The heel lining according to one of claims 1 to 5, in which the nonwoven fabric formed from the multi-component continuous filament is pre-calendered for pre-bonding. -8

7. The heel lining according to one of claims 1 to 6, in which at least one of the incompatible polymers which form the multi-component continuous filament, comprises an additive such as dyestuff pigments, permanently acting antistatic agents and/or additives having an influence on the hydrophilic or hydrophobic properties in quantities up to 15 % by weight.

8. The heel lining according to one of claims 1 to 7, in which the multi component continuous filament is non-crimped.

9 The heel lining according to one of claims 1 to 8, in which the nonwoven fabric is impregnated with a polymer at 20 to 50 % by weight of the initial weight of the nonwoven fabric.

10. The heel lining according to one of claims 1 to 9, characterised in that after grinding, a particularly fine Nubuck-like surface is achieved as a result of the micro filament ends exposed on the surface.

11. The heel lining according to one of claims 1 to 10, in which a melting adhesive has been applied to one side.

12. A method for producing a heel lining according to one of claims 1 to 11, characterised in that the multi-component continuous filaments are spun from the melt, aerodynamically stretched and immediately laid down to form a nonwoven fabric, with pre-bonding by way of pre calendering or needle-punching taking place and with the nonwoven fabric being bonded by means of high-pressure fluid jets as well as at the same time being split into supermicro filaments with a titre of < 0.2 dtex and subsequently being impregnated with a polymer.

13. The method according to claim 12, characterised in that bonding and splitting of the multi-component continuous filaments takes place in that the pre-bonded nonwoven fabric is subjected to treatment from high pressure water jets, alternately from both sides. -9

14. The method according to claim 13, characterised in that bonding and splitting of the multi-component continuous filament is carried out on a unit with rotary screen drums.

15. The method according to one of claims 12 to 14, characterised in that impregnation with a polymer takes place by means of an aqueous polyurethane latex dispersant.

16. The method according to one of claims 12 to 15, characterised in that follow-up treatment takes place by abrading or velour-finishing.