EP0966214A1

EP0966214A1 - Footwear lining material

Info

Publication number: EP0966214A1
Application number: EP98903159A
Authority: EP
Inventors: Susan Gwynneth Johnson
Original assignee: Texon Materiales SL; Texon UK Ltd
Current assignee: Texon Materiales SL; Noxet UK Ltd
Priority date: 1997-02-14
Filing date: 1998-02-06
Publication date: 1999-12-29
Also published as: AU5998498A; GB9703111D0; WO1998035574A1

Abstract

A lining material for footwear comprises up to 40 % by weight binder fibre e.g. polypropylene and the remainder substantially bulk fibre e.g. polyester. The binder fibre has a melting temperature up to 200 °C and at least 70 °C lower than the bulk fibre. The material is heat shrunk in its manufacture to consolidate the material by fusion incorporation of the binder fibre with bulk fibre, suitably by exposure to hot air.

Description

FOOTWEAR LINING MATERIAL

Technical Field ^■

5 The present invention relates to a footwear lining material.

Rar.kground Art

It will be appreciated that the majority of footwear includes a lining iϋ of some description to improve feel and wear resistance for the wearer. Traditionally, this lining material was a soft or sueded leather. However, more recently cost has required that synthetic materials are used. These synthetic materials are generally non woven fabrics impregnated with a binder compound e.g. latex.

15

Of particular interest with regards to the present invention are so- called heel grip materials. Previously, heel grip materials have been produced from non-wovens consisting of a matrix of fibres entangled by needle punching, water jets, spin melt or similar consolidation technique.

₂u This non-woven felt or fabric is then further bonded with a soft rubber impregnant as a binder. The purpose of this binder impregnant is to strengthen, stiffen and colour the material and so improve its physical properties particularly its abrasion resistance. Finally, it is normal to provide a sueded (buffed) surface to the material to improve aesthetic

₂5 appearance, as it will be appreciated the heel grip is quite noticeable when a shoe is on display for sale. In addition to adding to component material costs for the lining material, it will be appreciated that the additional processing stage of impregnating a binder compound into the material increases costs.

It is known to provide fusion bonded materials for footwear lining.

An example of such a fusion bonded material is that supplied by Camtex of England under the Trade Mark CAMBRELLE. Unfortunately, this material does not generally have sufficient body or friction for use in heel portions of footwear.

Disclosure of Invention

It is an objective of the present invention to provide a footwear lining material suitable for a heel grip and/or the quarter portion of footv/ear which is based upon consolidation of a felt without binder compound but retaining sufficient abrasion resistance and feel.

In accordance with the present invention there is provided a lining material for footwear, the material comprising up to 40% by weight binder fibre and the remainder substantially bulk fibre, the binder fibre having a melting temperature which is at least 70°C lower than the melting temperature of the bulk fibre and having a melting temperature of up to 200°C, said material having been heat shrunk by up to 10% in surface area at a consolidation temperature to consolidate the material by fusion incorporation of the binder fibre with the bulk fibre.

The binder fibre may be low melting polyester, polypropylene, bi- component polyester or any other heat shrinkable fibre type. The bulk fibre may be polyester or any other suitable fibre.

The final weight of the material may be preferably up to 300 g per square metre.

Preferably the material comprises 30% polypropylene, binder, fibre with polyester, bulk, fibre, the material consolidates at a temperature of 180°C. The bulk fibres have a decitex of 1.7.

Alternatively, the binder fibre may be 40% by weight bi-component polyester e.g. Hoechst T254 with a speciality fibre such as Dacron R T702W grooved polyester fibre to improve wicking. The consolidation temperature is 120 °C.

At least one surface of the lining material may be sueded to improve wearer feel.

Further in accordance with the present invention there is provided a method of making a lining material comprising the steps of:

a) forming a non- woven fabric or felt having up to 40 % binder fibre with the remainder bulk fibre; and

b) heating said non-woven fabric or felt with hot gas to a consolidation temperature to achieve fusion incorporation of said binder fibre and said bulk fibres with a resultant shrinkage in terms of surface area of up to 10% . In accordance with another aspect of the present invention there is provided a lining material a method of making a lining material comprising the steps of:-

(a) procuring a bulk fibre; (b) procuring a binder fibre having a melting temperamre of up to 200 °C and which is at least 70 °C lower than the melting temperamre of the bulk fibre;

(c) forming a non-woven fabric or felt having up to 40% binder fibre with the remainder bulk fibre; and (d) heating said non- woven fabric or felt with hot gas to a consolidation temperamre to achieve fusion incorporation of said binder fibre and said bulk fibres with a resultant shrinkage to consolidate the fabric or felt.

The consolidation temperamre may be up to 200 °C in a method in accordance with the invention.

Preferably, the fabric will be exposed to the consolidation temperamre for 10 minutes to ensure complete activation through the thickness of the material.

The non-woven fabric or felt may be cooled after heat shrinkage about a cooling roller mangle.

The heat shrunk non-woven felt may be split after cooling to provide final layers of lining material.

The final lining material layers may be sueded upon at least one surface to improve feel. „„„„ . 8/35574

Examples of the present invention will now be described by way of illustration only.

In the present invention a lining material is produced only from fibres with no separate binder compound added to consolidate and strengthen the material. The material is strengthened and stiffened to achieve the necessary resilience for a heel grip by incorporation of binder fibres. These binder fibres are incorporated with bulk fibres generally of a lower decitex to provide the lining material. The binder fibres have a lower melting point than the bulk fibres.

It will be appreciated that the bulk fibres have a low decitex in order to provide the necessary soft touch for the lining material. However, it is really important that they remain substantially unaffected by activation of the binder fibres. Thus, it has been found that there must be a temperature differential of at least 70 °C between the melting point of the binder fibres and the bulk fibres. The bulk fibres constitute at least 60 % by weight of the lining material and provide the structural matrix for the lining material whilst the binder fibres upon activation become at least flaccid by application of heat or other means. However, the binder fibres do not completely melt upon activation, the objective being to create fusion incorporation of the bulk fibres with the binder fibres. Thus, the bulk fibres generally become embedded within the binder fibres upon activation and as the binder fibres become heat shrunk by application of the activation heat these embedded fibres are drawn together to consolidate the lining material as required. The binder fibres thus achieve the necessary fusion bonding within the lining material to give it resilient abrasion strength and also achieve consolidation by shrink displacement of the bulk fibre within the non-woven structure, the surface area of the material being reduced, so that the density measured as gsm is increased.

As indicated above the binder fibres and the bulk fibres are initially combined using known felting techniques. Thus, these binder and bulk fibres are incorporated together to create a non-woven felt or fabric using needle fibre entanglement techniques or hydro-entanglement. This non- woven felt is presented to heat activation apparatus in order that the binder fibres become soft or similarly activated in order to incorporate or become associated with bulk fibres. It will be appreciated that the binder fibre could have a surface adhesive coating which is heat activated to which the bulk fibres become tacitly adhered. A second phase in the activation of the binder fibres is heat shrinkage. Thus, the incorporated or associated bulk fibres are similarly drawn with the binder fibres during the heat shrinkage stage. The heat shrinkage stage may occur while the fibre is hot or during a cooling stage after heat activation, the type of heat shrinkage is dependant upon the fibre used as the binder fibre in the lining material. After heat activation and resultant cooling whether forced or environmental, the lining material is substantially in a finished state (apart from splitting and/or sueding). However, it will be appreciated that the lining material can be dyed or treated in order to improve performance as a lining for footwear. For example, in addition to dyeing, the lining material may have at least one surface sueded to improve wearer feel in use.

In order to improve the economics of lining material manufacture, it is conventional to provide a thick gauge felt material which is consolidated and then split into final layers of lining material. Typically such final layers of lining material will have a weight of 300 gsm and an approximate gauge between 0.7 and 0.8 mm.

A significant advantage with the present invention is that the bulk fibre may comprise various speciality fibres in addition to simple structural matrix fibres. For example, grooved fibres could be incorporated in order to enhance wicking within the lining material, antibacterial or anti-static fibres could be incorporated to reduce bacterial activity and deodorant fibres could be incorporated to improve performance.

In accordance with the present invention an alternative method and material for footwear lining is provided which removes the necessity of wet processing for incorporation by impregnation of a binder compound. Obviously, if the lining material is dyed, the dyeing stage will be performed by a wet process but nevertheless the impregnation stage has been eliminated. Furthermore, by the elimination of a binder compound within the lining material it is possible to achieve full utilisation of speciality fibres incorporated into the lining material as these fibres are not covered by the binder compound.

It is of particular importance that the proportions of binder fibre and bulk fibre are highly regulated. Thus, the proportions of respective binder fibre and bulk fibre are determined principally by the type of fibre used for each function within the lining material. However, the binder fibre must have a lower melting temperature than the main constituent bulk fibre and after activation achieve the necessary consolidation and rigidisation of the fabric by shrink activation. The amount of rigidisation i.e. consolidation of the non-woven fabric by heat activation of the binder fibre is by its nature very specific. The degree of consolidation should be just sufficient to allow the finishing operations to be carried out successfully and to achieve certain physical performance targets but there should not be too much consolidation to make the lining material excessively harsh and rigid and so unacceptable for footwear. The level of binder fibre and the temperamre of activation of that binder fibre required to achieve these desirable objectives differs between types of binder fibre.

Modes for Carrying Out the Invention

In view of the above, two examples of binder fibre and bulk fibre combinations will be described below.

EXAMPLE 1

A polypropylene binder fibre and a polyester bulk fibre are appropriately combined using known non-woven felting techniques in a ratio of 30% by weight binder fibre to 70% polyester fibre. The polyester bulk fibre has a 1.7 decitex. The initial carded non-woven batt is consolidated by needle punching to a weight of approximately 600 gsm and a gauge of 2 mm. After appropriate felting the non- woven fabric is presented to heat activation apparatus in order to achieve a shrinkage in surface area in the order of 6% . The consolidation temperamre of the heat activation apparatus is 180°C. However, it will be appreciated that alternative consolidation temperatures could be used. By variation of the consolidation temperamre and the rate at which hot activation gas e.g. air is presented to the non- woven fabric, it is possible to control the weight of binder fibre and bulk fibre incoφoration and shrinkage and so consolidation of the non- woven fabric. Thus, any potential for stress induced distortion within the lining material can be relieved. However, in any event after heat activation with hot air, the consolidated lining material is generally passed through cooled rollers of a mangle arrangement. This stabilises the lining material in accordance with the shrinkage and consolidation achieved through the heat activation stage described above. EXAMPLE 2

A binder fibre of a bi-component polyester type e.g. Hoechst T254 is combined with a grooved polyester fibre e.g. Dacron R T702W. The binder fibre constitutes 40 % by weight of the material whilst the bulk fibre grooved polyester may constitute the remainder of the material but normally would be mixed with cheaper simple polyester fibre. As with Example 1 above, the batt of bi-component polyester binder fibre and grooved polyester bulk fibre are combined by known non-woven felting techniques. An initial batt of carded fibres is needle punch entangled to achieve a non-woven fabric of 600 gsm and a gauge of 2 mm. This non- woven fabric is then presented to hot air (gas) heat activation apparatus in which hot air at a temperamre of approximately 120°C is projected on to the non-woven fabric for a period of ten minutes with the result that the non- woven fabric is heat shrunk consolidated to an approximately 8% surface area loss relative to the original non-woven material. After appropriate dyeing and sueding it was found that the material had a tear strength in the longitudinal axis i.e. direction of fabric making in the order of 24 Newtons whilst in a transverse direction in the order of 16 Newtons. Furthermore, the lining material achieved significant surface wicking. The gauge of the material is in the order of 1 mm; however as indicated above the gauge is achieved possibly by splitting an original consolidated material.

Irrespective of the binder fibre and bulk fibre used, it will be appreciated that care should be given to the subsequent operations involved in lining material manufacture. For example, it is typical to dye lining materials at elevated temperamre and such elevated temperatures although enhancing dye pick up by the lining material can obviously /35574

11

further precipitate shrink consolidation of the lining material through partial reactivation of the binder fibre. Furthermore, in order to improve wear and possibly appearance at least one surface of the lining material may be sueded, thus care should be taken that the surface of the lining material does not become hairy.

The preferred manner of heat activation is using hot air as this ensures that through depth heating is achieved. It will be understood if heated rollers are used there is a severe possibility that surface portions of the non- woven fabric will become glazed i.e. over-activated whilst central portions are less activated with resultant lower consolidation. These factors may diminish lining material appearance and lead to unequal densities of the multiple splits subsequently produced from the material.

As indicated above the critical factor with regard to suitability for a heel grip footwear lining material is the abrasive resistance quotient in comparison with the boardiness of the material. These factors are mostly determined by the proportion of binder fibre incoφorated within the lining material and the temperamre of consolidation activation temperamre along with the period of exposure. It is important that the bulk fibres remain substantially stable and so it has been found there must be at least a 70 °C temperamre difference between melting temperatures for the bulk fibre and the binder fibre and preferably a higher difference. Furthermore, it is not desirable for the binder fibre to become fluid as it is an objective of the binder fibre to capmre the bulk fibre through surface association and, due to binder fibre shrinkage, to draw the bulk fibre and binder fibre into a further consolidated non- woven fabric mass. It will be appreciated that it is also in accordance with the present invention for the binder fibre to be selectively activated in terms of surface association with the bulk fibre and for shrinkage by alternative activation techniques including solvent application. Obviously, if a solvent is used this solvent should preferably be specific to the binder fibre and have little or no effect upon the bulk fibre type. The binder fibre can be coated with an activatable adhesive to achieve the appropriate association between the binder fibre and bulk fibre to enable the heat shrinkage consolidation effect described above.

Types of fibres that can be used for the binder fibre in the lining material include low melting polyester e.g. EMS K170, bi-component polyester fibres such as Hoechst T254 or T252 fibres, or polypropylene or other olefin based bicomponents.

The bulk fibre in the lining material can comprise a multitude of fibre types including speciality fibres in order to achieve desired performance within lining material. Thus, polyester fibre, Coolmax fibre, Dacron R T702W grooved polyester fibre or anti-bacterial fibre or anti- static fibre or liquid transportation fibre may be included within the bulk fibre component. Generally, the bulk fibres will be of a finer or lower decitex compared to the binder fibres as they constitute the bulk of the lining material and thus constitute a significant factor in the wear feel of the lining material. It will be appreciated that finer fibres generally present a softer surface to the wearer. The binder fibres constimting a smaller proportion of the lining material have a less significant effect upon the lining material wear feel and this effect is further diminished by the shrinkage resultant from activation. After formation of the finished lining material by activation as indicated above it is generally normal to split the material to provide several final lining material layers. These layers may then be further processed by dyeing or other post production procedures in order to enhance their value and performance within a footwear lining environment. For example, at least one surface of the final lining material layer could be sueded to present a better wear performance. Furthermore, as footwear may be considered a fashion item, aesthetic appearance is usually important and so the lining material being visible in footwear on display will normally be dyed with vivid colours to accenmate the appearance of the footwear. The lining material layer may also have various designs printed on it again to enhance footwear appearance on presentation for sale.

As there is no binder compound incoφorated into the present lining material it will be appreciated that the fibre manufacturers claimed performance for their fibres may be more readily achieved within the lining material without the blocking effect of the binder compound. Furthermore, a potential for degradation of the binding material and any problems associated with post manufacmre processing of the lining material due to binder compound are obviously diminished. A further significant advantage with regard to the present lining material is of course that if no binder compound is introduced subsequent to fabric formation, this reduces material component and production costs.

Claims

1. A lining material for footwear, the material comprising up to 40% by weight binder fibre and the remainder substantially bulk fibre, the binder fibre having a melting temperamre which is at least 70 ┬░C lower than the melting temperamre of the bulk fibre and having a melting temperamre of up to 200┬░C, said material having been shrunk by up to 10% in surface area at a consolidation temperamre to consolidate the material by fusion inco╧åoration of the binder fibre with the bulk fibre.

2. A lining material according to claim 1 wherein the binder fibre is selected from low melting polyester, bi-component polyester and polypropylene.

3. A lining material according to either one of the preceding claims having a weight of up to 300 g per square metre.

4. A lining material comprising 30% polypropylene binder fibre and polyester bulk fibre.

5. A lining material comprising 40% by weight bi-component polyester binder fibre and bulk fibre including grooved polyester fibres.

6. A lining material according to any one of claims 1 to 4 wherein the bulk fibre comprises a mixmre of strucmral matrix fibres and speciality fibres selected from grooved fibres, anti-bacterial fibres, anti-static fibres and deodorant fibres.

7. A method of making a lining material comprising the steps of: a) forming a non- woven fabric or felt having up to 40 % binder fibre with the remainder bulk fibre; and

b) heating said non-woven fabric or felt with hot gas to a consolidation temperamre to achieve fusion inco╧åoration of said binder fibre and said bulk fibres with a resultant shrinkage in terms of surface area of up to 10% .

8. A method of making a lining material comprising the steps of:-

(a) procuring a bulk fibre;

(b) procuring a binder fibre having a melting temperamre of up to 200 ┬░C and which is at least 70 ┬░C lower than the melting temperamre of the bulk fibre;

(c) forming a non- woven fabric or felt having up to 40% binder fibre with the remainder bulk fibre; and

(d) heating said non-woven fabric or felt with hot gas to a consolidation temperamre to achieve fusion inco╧åoration of said binder fibre and said bulk fibres with a resultant shrinkage to consolidate the fabric or felt.

9. A method according to either one of claims 7 and 8 wherein the hot gas is air.

10. A method according to any one of claims 7 to 9 wherein the consolidation temperamre is up to 200 ┬░C.

11. A method according to any one of claims 7 to 10 wherein the fabric is exposed to the consolidation temperamre for 10 minutes.

12. A method according to any one of claims 7 to 11 wherein the non- woven fabric is cooled by passing through a cooling roller mangle after heat activation.

13. A method according to any one of claims 7 to 12 wherein the binder fibres have a heat activated surface adhesive coating.

14. A method according to any one of claims 7 to 13 wherein the bulk fibres are a mixmre of strucmral matrix fibres and speciality fibres selected from grooved fibres, anti-bacterial fibres, anti- static fibres and deodorant fibres.

15. A lining material for footwear comprising up to 40% by weight binder fibre and the remainder substantially bulk fibre made by a method according to any one of claims 7 to 14.