GB1573139A

GB1573139A - Napped bonded fibrous sheets

Info

Publication number: GB1573139A
Application number: GB38305/77A
Authority: GB
Original assignee: Toray Industries Inc
Current assignee: Toray Industries Inc
Priority date: 1976-09-16
Filing date: 1977-09-14
Publication date: 1980-08-13
Also published as: DE2741527C3; FR2364762A1; DE2741527A1; DE2741527B2; JPS5650031B2; JPS5349168A; CA1095700A; IT1143824B; FR2364762B1

Description

(54) NAPPED BONDED FIBROUS SHEETS (71) We, TORAY INDUSTRIES INC., a corporation organised and existing under the laws of Japan, of 2 Nihonbashi-Muromachi, 2-chome, Chuo-ku, Tokyo, 103 Japan, 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:- The invention relates to napped bonded fibrous sheets and processes for producing them. The sheets may have a high-class, napped woolen woven fabric appearance and may be used for clothes, furnishings and wall coverings.

According to one aspect of the invention there is provided a napped bonded fibrous sheet comprising a fabric layer with naps on a surface thereof, the fabric layer being formed by a fibrous structure having applied to it a cured organic polymer and a high molecular weight elastomer, the naps being formed by fibres of the fibrous structure which fibres are arranged in bundles with root portions combined to a unitary strand and tip portions with at least some fibres of the bundles individually distinct.

According to another aspect of the invention we provide a process for preparing a sheet as defined above which process comprises applying a process for preparing a sheet as claimed in claim 1 which comprises applying a curable organic polymer to a fibrous structure comprising fibre bundle units, curing the polymer, subsequently applying an elastomer and thereafter buffing and/or raising the structure to form a fabric layer with naps on a surface thereof.

As a fibre constituting the fibrous structure of the sheet of the invention, a bundle of superfine fibres of less than 0.7 denier, especially less than 0.5 denier is preferred.

There are various processes for obtaining a bundle of super fine fibres. The process described in, for example, the U.S. Patent Specification No. 3,531,368 giving what is now commonly called an "islands-in-a-sea" type fibre is preferred for many reasons including ease of preparation, yield, dispersibility, qualitative stability, reproducibility, easily controllable structure and ease of intertwining to give the fibrous structure.

The fibre prepared by a process described in the U.S. Patent Specification gives a multi-component or composite fibre and when at least one component, the so-called sea component, is chemically or mechanically removed therefrom, superfine fibres consisting of the remaining, so called island, components are obtained as a bundle.

For example, tvpical cross sections of such composite fibres are shown in Figures 5(A), 5(D), and 5(F) of the accompanying drawings. When cross-sections of such "islandsin-a-sea" type fibres are observed, many island components are arranged separately dispersed and distributed in a sea component and the island components are continuous in the direction of the fibre axis. Any number (n) of island components may be used however, usually n is smaller than 1000.

As the island components which ultimately give the fibres of the fibrous structure there may be used polyesters such as polyethylene terephthalate and copolymers thereof with monomers such as isophthalic acid, sodium sulphonate isophthalate and polybutylene terephthalate. Non-polyester polymers such as polyamide 6, 66 and 6-10; polypropylene, polyethylene and polyacrylonitrile may also be used. The "islands-ina-sea" type fibre is not limited as to cross-sectional shape and may be hollow or have a nonsircular cross section.

Many studies of that type of composite fibres have been carried out. The polymer blend, the characteristics of polymers, the blending conditions and the spinning conditions can be selected so that in the resulting composite fibres one component is continuous and thin and embedding in another component. A bundle of fibres bound by a binding agent may be spun by a method which comprises passing two kinds of polymer through a labyrinthian mixer (vib-mixer or static mixer) to promote division and integration of the two kinds of polymer, thereafter, passing these polymers through a filter to change their filmy state to a fibre-like state and spinning, superdraw spinning and drawing or superfine wet spinning. A multi-component fibre is thus produced capable of forming a bundle of superfine fibres or of fibrillating by dynamic, strong rubbing. The fibre may exhibit characteristics similar to those of the multicomponent fibre having a cross-section such as shown in Figure 5(B) and 5(C) or 5(A) of the accompanying drawings in which the proportion of island components is large. Using the appropriate fibres, fabrics are prepared to form the fibrous structure of the sheets of the invention.

The fabric may be woven, knitted or non-woven. In the case of a non-woven fabric, it is possible to make the appearance of the sheet like that of a napped woollen woven fabric even though it is a non-woven fabric. The non-woven fabric may be obtained by needle punching a monolayer web or a multi-layer web formed with a random webber and a cross lapper. It is especially preferred to slice and halve the fabric following impregnation.

In case the fabric is made up of "islands-in-a-sea" type multi-component fibres, it is necessary to remove or separate the sea component except in the case in which the proportion of the sea component is small. The sea component should then be removed before the hardenable organic high molecular weight compound is applied to the fabric. When the sea component is removed or separated the fabric becomes soft. However, when the overall fibre density is low, the fabric becomes too soft having regard to the handling which will take place subsequently. In such a case, it is preferred to apply to the fabric in advance, a water-soluble or hot water-soluble sizing agent such as polyvinyl alcohol, a partly saponified polyvinyl alcohol, carboxymethyl cellulose, methyl cellulose, sodium polyacrylate, polyacrylamide and starch.

Application may be effected by impregnating methods such as dipping and coating followed by squeezing and drying. The sizing agent is removed when necessity for fixing the shape of the fabric has disappeared. The agent is preferably removed after the fibrous structure has been treated with an elastomer. However, the sizing agent may be removed prior thereto as the case may be. In case the sea component of the "islands-in-a-sea" type fibre is polystyrene or a copolymer of polystyrene or a monomer of the vinyl series, one solvent or a combination of at least two solvents selected from trichloroethylene, perchloroethylene, toluene, xylene and benzene may be used as a removing agent.

To the so obtained fabric there is applied a hardenable organic high molecular weight compound and thereafter, said compound is hardened. As such hardenable organic high molecular weight compound, there may be used an organosilicone compound (in a solution or emulsion) or a self-cross-linking type acrylic resin emulsion, of which the most effective compound for the invention is a high molecular weight organosilicone compound. A typical example of a hardenable high molecular weight organosilicone compound is a combination of polyorganosiloxane with a chemical such as catalyst necessary for hardening (which may include curing and vulcanization in the case of a rubber, which is included here). Silicone rubber is especially useful.

Silicone rubber may be prepared by different processes. There are, for example, a single liquid-type silicone rubber and a two liquid-type. Each of these types can be made using condensation reaction or an addition reaction and a ring-opening reaction. In many cases, the silicone rubbers react at a relatively low temperature such as room temperature, but may also react under the influence of moisture and at a high temperature.

Single liquid condensation reaction type silicone rubbers include: (1) Acetic acid-removing condensation type:

(2) Oxime-removing condensation type:

(3) Alcohol-removing condensation type:

(4) Amine-removing condensation type:

(5) Amide-removing condensation type:

Single liquid addition reaction type silicone rubbers include: (1) Vinyl-addition reaction type:

(2) Peroxide type:

I A -Si-CH,ICH,=CHSi- ------- -Si-CH,-C-H,-CH,Si I peroxide Two-liquid condensation reaction type silicone rubbers include: (1) Alcohol-removing condensation type:

Example of catalyst: metal salt of fatty acid (2) Hydroxylamine-removing condensation type:

(3) Dehydrogenation condensation type:

Two-liquid addition reaction type silicone rubbers include: (1) Vinyl-addition reaction type:

Example Catalyst: platinum compound.

(2) Ring-opening reaction type silicone rubbers include:

The main skeleton is a polysiloxane, typically polydimethyl siloxane besides which the skeleton may comprise a little or considerable part of phenyl groups, hydrogen atoms or vinyl groups. The additional groups may influence crosslinking reactivity. Epoxy groups having ring-opening reactivity may be used also. Terminal groups may be

These terminal groups react between themselves or with various silanes. For the reaction, water including water vapour, a platinum compound such as chloroplatinic acid, peroxide, an organometallic compound such as a metal salt of fatty acid, a radical-releasing compound and an aminosilane compound may be used as appropriate.

The molecular weight of the main skeleton is preferably from 10,000 to 1,000,000.

The physical properties of the cured organic polymer benefit from addition of silicon oxide such as silica in aerosol form. Besides, titanium oxide, carbon black, calcium carbonate, diatomaceous earth, quartz powder, asbestos, zinc oxide and zirconium silicate may also be added.

The silicone rubbers are preferably treated with chain or cyclic silane, silanol, siloxane and silazane. It goes without saying that besides these, various additives such as a colouring pigment and an extracting agent for increasing porosity may be used.

Information on silicones is contained in Patents of Dow Corning Co. of U.S.A., and various technical papers provided by Toray Silicone Co., Toshiba Silicone Co.

and Shinetsu Chemical Industries Co., all of Japan.

As the latest literature there are Japanese Patent Application Publication Nos.

27704/1976, 27705/1976 and 27706/1976 (Dow Corning Co.), laid-open Japanese Patent Application No. 94295/1975 (Dow Chemical Co. of Great Britain), Japanese Patent Application Publication No 27703/1976 (Kuraray Co. of Japan), Japanese Patent Application Publication No. 24303/1976 (Toshiba Silicone Co.), Japanese Patent Application Publications Nos. 24301/1976, 24302/1976, 23977/1976, 23979/1976, 25069/1976, 28308/1976, 28309/1976 and 28310/1976 (Shinetsu Chemical Industries Co.) as well as laid-open Japanese Patent Applications Nos.

34291/1976, 39773/1976 and 49995/1976 (Shinetsu Chemical Industries Co.), in resinification of silicone for various objects is disclosed.

In the invention, a fibrous structure has applied to it, generally by impregnation, a curable organic polymer such as an organosilicone compound. The polymer preferably has a viscosity at which it impregnates easily in the unreacted state. Therefore, it is possible to directly impregnate the fibrous structure. Preferably the polymer is in the form of a solution, emulsion or dispersion because in such state, not only is it easy to apply by impregnation said polymer, but it also has excellent uniformity and can be applied reliably in the required quantity. The solvent or dispersion medium of such silicone compounds are removed later by for example drying. Subsequently a curing reaction of the polymer is caused to proceed once it has been applied, coagula tion of emulsion particles is caused to proceed or the curing reaction and the coagulation are caused to proceed simultaneously. For example, when the curing reaction is effected by heating, a sheet is passed through a heating zone, and when the reaction proceeds at ambient temperature, e.g. by exposure to moisture in the air, the sheet is allowed to stand in the air for a sufficient period of time. As the polymer is generally applied in atmospheric air containing moisture, it is preferred to select a polymer permitting curing by heating.

As mentioned above, when the sizing agent is used it is necessary to effect heating so as not insolubilized said agent or melt the fibre per se.

The silicone is thus cured in the appropriate manner and is located and adhered m a space formed by bundles of fibres. Because of its surface tension, silicone tends to adhere to the inside and around the bundles of fibres and to the intersecting points of bundles of fibres. In order to further promote this tendency, it is preferable to use a silane coupling agent either in advance or in admixture for a reason which will be mentioned later.

Next, the elastomer i.e. plastic polymer such as polyurethane is applied. The elastomer is preferably applied as a solution or an emulsion. When the silicone is silicone rubber, a two-stage impregnation of the elastomers may be used. After coagulation and fixation (solidification), removal of the sizing agent may be effected by washing if necessary. When a solvent is used, it is preferable that a greater part or substantially all of the solvent used is removed together with the sizing agent.

As the elastomer, polyurethane of the ether series, polyurethane of the ester series (polyurethane is considered to be any polymer including a urea bond, including blockand co-polyurethanes), polyurethane of the ether ester series, and all of various rubbers such as natural rubber, chloroprene rubber, SBR and NBR may be used. Materials which are not effected detrimentally at dyeing temperatures are preferred.

One example of a preferred combination is: polyester as the fibre, partly or completely saponified polyvinyl alcohol as the sizing agent, silicone rubber as the curable organic polymer and polyurethane as the elastomer.

Polyurethane is most often prepared from a reaction of a polyol with diisocyanate.

As a polyol precursor there may be used polytetrahydrofuran, polycaprolactone and polyhexanediol adipate alone or in admixture; as isocyanate there may be used diphenylmethane-4,4'-diisocyanate (MDI) and hydrogenated MDI alone, in admixture or in a multi-stage reaction; and as a chain extender there may be used ethylene glycol, butylene glycol, hydrazine and methylene bis-aniline (MBA) are used alone, in admixture or in a multi-stage reaction.

The sheet which is produced is finally buiifed. As occasion demands, it may be sliced, buffed and napped. Sometimes it is buffed after necessary treatments are carried out. A napped grey fabric, when not spun dyed, is commonly dyed subsequently.

When the material is polyester, it is dyed with a dispersed dye. When the material is modified it may be dyed with a basic dye. If the fabric is of nylon such as nylon 6 or nylon 66, it may be dyed with a wide selection of acid dyes.

After the sheet has been dyed, it is preferred to wash it in a liquor containing reducing agent. Finishing agents may be applied to the sheets after dyeing. This may improve the feel, lustre, touch and softness of the sheets.

After dyeing, upon drying the fabric, it is preferable to wet comb or smooth the nap down with a brush in a direction parallel with or contrary to the direction in which the sheets pass through a dyeing machine and/or the direction of buffing.

The invention is more particularly described by reference to the drawings in which: Figure 1 is a schematic sectional view of one embodiment of a nap of a composite sheet according to the invention; Figure 2(a) and Figure 2(b) are partial enlarged views of Figure 1; Figure 3 is a schematic view showing a section through a nap surface of a conventional suede-like sheet; Figure 4 is a schematic view illustrating the relation between fibres and two kinds of high molecular weight compound of the sheet of Figure 1; and Figure 5A to F show examples of cross sections of fibres suitable for preparing superfine fibres for sheets according to the invention.

The napped state of the sheet material finished as described has an appearance similar to that of a high-class napped woollen woven fabric as sketched in Figure 1.

The nap differs greatly from that of a conventional suede-like fabric. In this example, the nap is bound into bundles or strands by means of hardened silicone. Some bundles have a decreased number of fibres from halfway to one end and are tapered by buffing.

In Figures 1 and 2 a tip of a superfine fibre 1 leads to a part 2 where fibres are bound together, but decrease in number thus forming a slender bundle connected to a part where superfine fibres are bound together.

By contrast when silicone is absent and polyurethane only is used, the fabric has a suede-like nap as shown in Figure 3. The part 4 close to the tip of nap is connected to a slender root portion 5 of the nap. In such a fabric having a suede effect, the nap lies flat to a greater extent than is shown in many cases.

With reference to Figure 4 when the relation of bundles of fibres with the two kinds of high molecular weight compound which is the essence of the invention is shown diagrammatically in Figure 4, fibres 6 are embedded in hardened silicone 7 surrounded by a skin of polyurethane 8. The skin 8 may adhere to the silicone 7 locally and partly or surround it entirely as shown in Figure 4. Figure 4 is typical of the relative distribution in the fabric layer and in the nap. Parts forming nap after buffing consist of the fibres 6 and the silicone 7 while the skin 8 comes off at the time of buffing. The fibres 6 and the silicone 7 are held at the roots, but at the tips the silicone 7 may come off or parts of the fibres 6 and the silicone 7 are simultaneously scraped off, becoming thinner or separating and assuming a tapered or dispersed form toward the tip. It is because of such nap arrangement that the composite sheet of the invention can have an appearance like that of a high-class woollen woven fabric.

In a composite sheet of the invention, the root portions are bound together and thick, while the tip portions become slender or have slender branches. A satisfactory feel results. The main structure of the bundles is a bundle of fibres obtained by removing by dissolution or mechanically peeling the sea component from an "islands- in-a-sea" type fibre. However thicker bundles each comprising several bundles of fibres from "islands-in-a-sea" type fibres created by needle punching may be present.

The root portion is thick, and the nap becomes firm. Compared with sheets in which fibres are not bound, namely, a suede-like fabric, a sheet of ~the present invejitiojiTs unlikely to show a nap which can be reversed. It is then free from a suede-like effect, and gives a napped woollen woven fabric-like appearance. Taper is considered to be brought about by using bundles of originally slender fibres, by the fact that tips are scraped off by buffing and by the fact that the unity of bundles is broken up. On the other hand, the elastomer such as polyurethane is naturally located around the hardened silicone which first occupies a place around fibres. When adhesion of such elastomer to the hardened silicone is poor, the elastomer such as polyurethane present on the nap may well be stripped off and removed at the time of buffing. The unity of fibres with silicone may, in certain cases, be weak. In such cases the composite sheet becomes suede-like leaving behind a hardly meltable effect because hardened silicone is removed at the time of buffing and the nap is formed from only the fibres, but is not bound with the silicone.

In the invention, it is preferred that the bonding strength between the superfine fibres and the hardened high molecular weight organic compound is stronger than that between the hardened high molecular weight organic compound and the elastomer.

The bonding strength between the bundle of superfine fibres and the hardened high molecular weight organic compound may be such that after buffing and/or raising, more preferably after dyeing, continued adherence of the hardened high molecular weight organic compound to the bundle of superfine fibres can be observed under a microscope. The following conditions are perferable. Namely if criteria A and B are defined as: A: the relative physical properties of the fibre and the cured silicone B: the relative physical properties of the cured silicone and the elastomer It will be seen from observation of the nap of a prepared sheet, it is preferred that A is relatively high in adherence and affinity, and from the viewpoint of feel and touch of said fabric, it is preferable that B is relatively low in adherence and affinity.

The balance between A and B is important.

It is preferred that the bundles of fibres are treated with a silane coupling agent or have said agent added to it before they are spun. Various silane compounds, especially a silane coupling agent used ordinary to treat aerosol silica and diatomaceous earth with silane, may be used for improving adherence to silicone resin and another polymer. In this case an inverse sequence is used whereby a fibre is treated with a silane coupling agent in advance. It is possible to add a silane coupling agent to bundles of fibres so as to improve the reception of the cured silicone upon spinning the fibres.

It is preferred to add a silane coupling agent to silicone to be cured or use curable silicone containing a substance functioning as a silane coupling agent for the curing reaction. Thus, excellent physical properties and adhesive strength to fibres of cured silicone required in criterion A, are preferable.

Examples of a silane coupling agent for polyester, for example, are as follows

For polyamide, for example, c. above may be used together with a reaction promotor or by itself.

As mentioned above, where bundles of superfine fibres and curable silicone are made to bond strongly, it is necessary to reduce the ratio of the hardenable silicone to (another later imparted) elastomer As regards criterion B, it is desirable to avoid strong adherence from the viewpoint of feel and touch. However, from the viewpoint of preventing nap from falling out the adherence must not be too low. The curable silicone and the elastomer tend to adhere poorly but in order to reduce adherence further, it is preferable to add to these, in advance, a component which increases mould-releating properties and ease of sliding such as polyorganosiloxane or a fluorine compound which is not of a curable type, but of a commonly mould-release type. Upon using the silane coupling agent, it is preferable to take care not to increase adherence of the curable silicone to elastomer. When, for example, a silane coupling agent is mixed with curable silicone and used, when the fibre is for example polyester, it is necessary to pay attention to selecting such agent so that the agent does not adhere too strongly to such polyurethane even if it is possible to increase the adhesive strength of the agent to polyester when the high molecular weight elastomer is polyurethane. It is preferred to treat the sheet as a whole with various fibre treating agents for advancing mould-releasing and ease of sliding such as silicon and paraffin after completing the treatment of the sheet with curable silicone. In this way feel after the subsequent treatment with an elastomer can be improved and it may facilitate buffing.

If emphasis is placed on making a good nap which is unlikely to fall out at the expense of the feel of the sheet it is preferred to increase the adherence between the fibre and the silicone. For example, in order to prevent the nap of a product after it is dyed from falling out it is preferred to treat the product with a selfcrosslinking acrylic emulsion and a silicone rubber (resin) forming liquid or emulsion thereof.

Although it is apparent that if such treatment for preventing nap from being lost is pursued too far, it would hurt the feel, nap and the touch thereof, it is possible to control such treatment by adjusting the extent of the treatment for example, by changing the concentration at the time of treatment.

As regards the amounts of a curable organic polymer and the elastomer to be imparted to a fabric, it is preferred that the total of the two is from 15 to 70 parts by weight based on 100 parts by weight of the sheet after impregnation. The ratio of the curable organic polymer to the elastomer is preferably from 0.5 to 30% by weight, especially from 0.5 to 20% by weight of the former to 100% by weight of the latter.

A composite sheet according to the invention may be used for clothes such as coats, blazers, sports shirts, hats, furniture such as upholsteries and bed covers, wall materials, carpeting, ornaments, shoes such as boots, handiwork materials and pouches such as bags. The sheets may be dyed to a deep colour, have good bulk, smooth touch, washable in water, have easy-care properties, crease resistance and not form lasting creases on packing. The sheets can permit sliding, having a good lustre and resistance to burning cigarettes, do not fray easily at their edge and are lightweight.

It may be sewn without a hemstitch and does not handle like leather. The nap is firm and not easily relaid by brushing. Pilling and nap entanglement is low. The sheets are durable.

The invention is illustrated by the Examples. All parts and percentages are by weight unless otherwise indicated.

Example 1.

Using cut fibres of an "islands-in-a-sea" type fibre whose cross section was as shown in Figure 4, whose sea component was a blend of polystyrene and polyethylene glycol in a ratio of 47.5 to 2.5, whose island component was polyethylene terephthalate; and having a sea/islands ratio of 50/50, a number of islands of 16, a denier of the "islands-in-a-sea" type fibre of 3.2 d, a number of crimps of 13 inch and a cut length of 51 mm, a web was formed by a cross lapper method, which was needle punched at 3300 punches per sq cm to obtain an intertwined non-woven fabric having a weight per unit area of 500 g per sq m and an apparent density of 0.19 g per cc.

When this non-woven fabric was further contracted in hot water at 97 to 1000 C, its weight per unit area became 833 g per sq m and its apparent density became 0.379 g per cc in a dried state. One hundred parts of this non-woven fabric (of the "islandsin-a-sea" type fibre) was impregnated with about 40 parts (calculated as solid) of a solution of polyvinyl alcohol whose degree of saponification was about 80% and dried. Using trichloroethylene, 99.2% of the sea component was removed.

This non-woven fabric from which almost all of the sea component had been removed was impregnated with 250% (in wet weight) of a silicone treating liquid prepared by dissolving in advance, 30 parts of a silicone composition containing (a) 95 parts of polydimethylsiloxane having a terminal --OH group and a molecular weight of 25,000 (250C, 3000 CS) and (b) 5 parts of partly condensed CH3Si(OCH3)3 in 967 parts of trichloroethylene. Next, while stirring the resultant solution, 3 parts of (CH3O)sSi (CH2),NHCH2CH2NH2 were added thereto.

At about 70"C, a greater part of trichloroethylene was driven off and the impregnated non-woven fabric was allowed to stand in air at a room temperature of 25"C and a relative humidity of 60% for 24 hours to complete hardening of the silicone. The adhered amount of silicone was 7.9% calculated as solid and the adhered amount of silicone per unit area was 59.3 g per sq m at this time.

This non-woven fabric was then impregnated with a dimethyl formamide solution of polyurethane so that the adhered amount of polyurethane calculated as solid became 60 parts based on 100 parts of the island components. The polyurethane was coagulated in a water bath and the polyvinyl alcohol removed, and then fabric sliced into 2 equal thickness non-woven fabrics, each of which was buffed on the non-sliced face (surface) to form a napped surface and dyed under pressure with a dispersed dye at 125"C. This product looked like a woollen woven fabric, having a puffy appearance, at the time time, a soft pliant feel, being different from the conventional natural suede material and also artificial suede products.

A comparison of a product according to the invention and another product not according to the invention prepared without passing through a silicone-treating step will be shown in Table 1.

TABLE 1 - Characteristics of the product.

Product A product according to the A comparative product not Characteristics present invention according to the invention obtained without passing through a silicone treatment Overall appearance Deep in colour, like that Like that of leather suede of a puffy woollen woven fabric Feel Soft and puffy Like that of leather suede Nap Hardly having directionality, Having directionality, consisting mainly of nap as consiting of nap as shown shown in Figure 1 in Figure 3 Sewing properties like those of a napped woolen Like those of leather suede woven fabric Melt resistance 1)* About 10 seconds (about 3 About 3 seconds (time until a hole times that of the was opened by light comparative product) of a cigarette) Tear strength L.* 2.02 0.68 (kg) B.* 2.81 0.59 ~ Tensile strength L.* 55.4 74.8 (kg per sq cm) B.* 56.3 65.2 Tensile L.* 90 74 elongation (inc) B.* 116 107 Brush abrasion strength index 2)* 164 100 Light resistance (fade-o-meter, 20 hrs.)- 3)* Above grade 5 Grade 5 Washing fastness (discolouration, fading) Grade 5 Grade 5 Dry cleaning (discolouration, fading) Grade 5 Grade 5 Note 1)* Time since "Hi-lite" cigarette was lit until a hole was made on the sample by self-weight of the cigarette.

2)* Frequency of revolution of a round nylon brush until a hole began to be made thereby, shown by an index based on that of a comparative compound which was made 100.

Table 1 notes continued.

L.* Length B.* Breadth 3)* Grade 5

Grade 1 Hardly discoloured Much or faded discoloured Example 2.

The same fibre as in Example 1 was treated as in Example 1 to prepare a non - woven fabric of an "islands-in-a-sea" type fibre, from which the sea component was removed. The so obtained non-woven fabric was impregnated with 250% in wet weight of a silicone treating liquid prepared by dissolving in advance, 80 parts of a silicone composition containing (a) 95 parts of polydimethylsiloxane having a terminalOH group and a molecular weight of 25,000 (25cm, 3000 CS) and (b) 5 parts of partly condensed CH,Si(OCH,)3 in 912 parts of trichloro ethylene. Next while stirring the resultant solution, 8 parts by weight of (CH,O ) 3Si(CH2) ,NHCH2CH2NH2 were added thereto.

After driving off a greater part of trichloroethylene at 70 C, the impregnated non-woven fabric was allowed to stand in the air at a room temperature of 25 C and a relative humidity of 60% for 48 hours to complete the hardening of the silicone.

The adhered amount of silicone calculated as solid was 19.3% and the adhered amount of silicone per unit area was 142.5 g per sq m at this time.

This non-woven fabric was further impregnated with a dimethyl formamide solution of polyurethane containing a black pigment (8% of a carbon black prepara tion based on the solid component of polyurethane) so that the adhered amount of polyurethane calculated as solid became 60 parts based on 100 parts of the island components. Thereafter, the fabric was processed according to Example 1.

The non-woven fabric was dyed in a deep colour using a dispersed dye under pressure at 1250C. Because the silicone did not contain carbon black, it was feared that the colour of the product would be indistinct. However, the colour of the product was unexpectedly deep, becoming a very good looking tint. The other properties were approximately the same as those of Example 1.

The characteristics of a product obtained in accordance with the invention are shown in Table 2.

TABLE 2 Characteristics of the product (concerning the characteristics of a comparative product. refer to Table 1)

Product A product according to the present invention Characteristics Overall appearance Deep in colour, a puffy appearance like that of a woollen woven fabric Feel Having no directionality, consisting mainly of nap as shown in Figure 1 I Sewing properties Like those of a woollen woven fabric Melt resistance (time until"""d~ a hole was opened by light of a cigarette) About 12-seconds Tear strength (kg) L.* 1.43 B.* 1.70 Tensile strength L.* 41.8 (kg per sq cm) iB.* 51.0 Tensile elongation (b) 1 65 I I Schiefer abrasion strength index 108 Light resistance (fade-o-meter, 20 hrs.)- Grade 5 Washing fastness (discolouration, fading) Grade 5 Dry cleaning (discolouration, fading) Grade 5 Note: L.* Length The testing methods were according to those of Example 1.

Example 3.

The same fibre as in Example 1 was used in preparing a non-woven fabric of an "islands-in-a-sea" type fibre, from which the sea component was removed and the fabric was treated with a reaction type silicone all in the same manner as in Example 1.

Next, this non-woven fabric was further impregnated with a dimethyl formamide solution of polyurethane containing a black pigment (8% of a carbon black preparation based on the solid component of polyurethane) so that the adhered amount of polyurethane became about 60 parts in solid based on 100 parts of the island components.

Thereafter, said fabric was processed according to Example 1.

The non-woven fabric was dyed in a deep colour using a dispersed dye with pressure at 125"C. As in Example 1, the colour of the product was deep, and a napped product with a high-class colour effect and having an appearance like a woollen woven fabric, was obtained.

Example 4.

The same fibre as in Example 1 was used in preparing a non-woven fabric of an "islands-in-a-sea" type fibre, from which the sea component was removed in the same manner as in Example 1. The resultant non-woven fabric was impregnated with about 250% in wet weight of a silicone treating liquid which was reactive upon heating prepared from the following components: (a) 942 parts of trichloroethylene (2) 50 parts of a mixture

(c) 1 part by weight of

R being alkylstyrene (a-methyl-styrene type).

(d) 7 parts by weight of (CH,CH2CH2CH2),Sn(OCOCH,)2 Next, after driving off a greater part of trichloroethylene at 700 C, the fabric was heat-treated at 1300C for 7 minutes. The adhered amount of silicone calculated as solid was 12.7% and the adhered amount of silicone per unit area was 92 g per sq m at this time.

The non-woven fabric was further impregnated with a dimethyl formamide solution of polyurethane containing a black pigment (8% of a carbon black preparation based on the solid component of polyurethane) so that the adhered amount of polyurethane became 60 parts based on 100 parts of the island components. Thereafter, the fabric was processed according to Example 1 and dyed in a deep colour. The dyed product had about the same appearance, properties and feel as those of Examples 1 to 3 although it was somewhat inferior in deepness of the colour as compared with those of Examples 1 to 3.

Example 5.

The same fibre as in Example 1 was used in preparing a non-woven fabric of an "islands-in-a-sea" type fibre, from which the sea component was removed all in the same manner as in Example 1, which was impregnated with about 250% in wet weight of a silicone treating liquid which was reactive upon heating prepared from the following components: (a) 956 parts of trichloroethylene (b) 40 parts of

t ICH3 1CH3 t:" silchSS SiO OC5CH-sCH2 O (R: alkylene group) (c) 4 parts by weight of (CH3O),Si(CH2),NHCH2-CH2NH2 Next, after driving off a greater part of trichloroethylene at about 70"C, said non-woven fabric was heat-treated at 1300C for 7 minutes. The adhered amount of silicone calculated as solid was 10.65-/C and the adhered amount of silicone per unit area was 74.57 g per sq m.

This non-woven fabric was further impregnated with a dimethyl formamide solution of polyurethane containing a black pigment (0.5% of a carbon black preparation based on the solid component of polyurethane) so that the adhered amount of polyurethane became 60 parts based on 100 parts of the island components. Thereafter, the non-woven fabric was processed according to Example 1 and dyed in a medium deep colour.

As compared with the products of Examples 1 to 4, the dyed product had an appearance and properties of somewhat longer nap, increased lustre on the surface, a very soft and pliant feel different from those of the conventional natural leather and artificial suede-like leather products. The deepness of the colour was about the same as those of Example 1 to 3.

Example 6.

Using cut fibres of an "islands-in-a-sea" type fibre whose cross section was like Figure 4, whose sea component was polystyrene, whose island component was polyethylene terephthalate, having a sea/islands ratio of 43/57, a number of islands of 16, a denier of the "islands-in-a-sea" type fibre of 3.4 d, a number of crimps of 13 per inch and a cut length of 51 mm, a web was formed by a cross lapper method, which was needle punched at 3500 punches per sq cm to obtain an intertwined non-woven fabric having a weight per unit area of 540 g per sq m and an apparent density of 0.185 g per cc. When this non-woven fabric was further contracted in hot water (at 97-1000 C), its weight per unit area beame 820 g per sq m and its apparent density became 0.372 g per cc in a dried state.

One hundred parts of this non-woven fabric (of the "islands-in-a-sea" type fibre) was impregnated with about 23 parts (calculated as solid) of a solution of polyvinyl alcohol whose dgeree of saponification was 80%, dried. Using trichloroethylene, 99.8% of the sea component was removed.

This non-woven fabric from which almost all of the sea component had been removed was impregnated with 250% in wet weight of a silicone treating liquid prepared by dissolving in advance, 50 parts of a silicone composition containing: (a) 95 parts of partly condensed polydimethyl siloxane having a terminal of -OH and a molecular weight of about 25,000 (at 25"C, 3000 CS), and (b) 5 parts of partly condensed CH3Si(OCH,)3 in 945 parts of trichloroethylene. Next while stirring the resultant solution, 5 parts of (CH,O,Si(CH2 ) ,NHCH2CH2NH2 were added thereto.

At 700 C, a greater part of trichloroethylene was driven off and then the impregnated non-woven fabric was allowed to stand in the air at a room temperature of 25"C and relative humidity of 60% for 24 hours to complete hardening of the silicone. The adhered amount of silicone calculated as solid was 12.9% and the adhered amount of silicone per unit area was 82 g per sq m at this time.

This non-woven fabric was further impregnated with a dimethyl formamide solution of polyurethane containing a black pigment (8% of a carbon black preparation based on the solid component of polyurethane) so that the adhered amount of polyurethane calculated as solid might become 48 parts based on 100 parts of the island components, coagulated in a water bath, removed of polyvinyl alcohol and dried.

Next, from 6 to 9% calculated as solid of a self-crosslinking acrylic-type emulsion resin ("Ultrasol -- 2613" (registered Trade Mark), a product of Takeda Pharmaceutical Industries Co. of Japan) added with a small amount of a migration preventing agent with a view to decreasing number of nap lost, from which the moisture was removed, was imparted to this processed non-woven fabric and thereafter said fabric was heat-treated at 1400 C for 6 minutes.

The processed non-woven fabric which had been treated so as to prevent nap from being lost was sliced into two equally thick parts and thereafter, said fabric was processed into a napped non-woven fabric and dyed to a deep colour according to Example 1.

The dyed product was a product having a good preservation of nap in addition to the appearance, feel and properties of the products of Examples 1 to 3.

The results of testing the product in respect of nap preservation will be shown below.

Properties of products after being treated for preventing nap from being lost.

PP* pp* Nap losing Surface This resistance properties Feel T* N ,* wMS This Example 12.9 0 A O O 6.1 A-O O 0 0 0 0 0 8.8 0 0 0 Control 7.8 0 A O O " 5.2 A-O O O 7.8 0 0 0 " 11.6 0 O A-O 18.4 0 A 0 0 5.1 A 0 0 " 6.4 A-O 0 0 8.6 0 O O Note: Nap preservation 0: Very few or no naps were lost A: a few naps were lost Surface properties O: good and feel A: somewhat poor T* Test S* Adhered amount of silicone (NO) M* Adhered amount of a migration preventing agent ( WO) PP* Properties of the product.

WHAT WE CLAIM IS: 1. A napped bonded fibrous sheet comprising a fabric layer with naps on a surface thereof, the fabric layer being formed by a fibrous structure having applied to it a cured organic polymer and a high molecular weight elastomer, the naps being formed by fibres of the fibrous structure which fibres are arranged in bundles with root portions combined to a unitary strand and tip portions with at least some fibres of the bundles individually distinct.

2. A sheet according to claim 1 in which the majority of the fibres consists of bundles of superfine fibres of less than 0.7 denier.

3. A sheet according to claim 1 or claim 2 in which the fibres are polyester fibres.

4. A sheet according to any of the preceding claims in which the cured organic polymer is an organosilicone polymer.

5. A sheet according to claim 4 in which the organosilicone polymer is a silicone rubber.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Properties of products after being treated for preventing nap from being lost. PP* pp* Nap losing Surface This resistance properties Feel T* N ,* wMS This Example 12.9 0 A O O 6.1 A-O O 0 0 0 0 0 8.8 0 0 0 Control 7.8 0 A O O " 5.2 A-O O O 7.8 0 0 0 " 11.6 0 O A-O 18.4 0 A 0 0 5.1 A 0 0 " 6.4 A-O 0 0 8.6 0 O O Note: Nap preservation 0: Very few or no naps were lost A: a few naps were lost Surface properties O: good and feel A: somewhat poor T* Test S* Adhered amount of silicone (NO) M* Adhered amount of a migration preventing agent ( WO) PP* Properties of the product. WHAT WE CLAIM IS:

1. A napped bonded fibrous sheet comprising a fabric layer with naps on a surface thereof, the fabric layer being formed by a fibrous structure having applied to it a cured organic polymer and a high molecular weight elastomer, the naps being formed by fibres of the fibrous structure which fibres are arranged in bundles with root portions combined to a unitary strand and tip portions with at least some fibres of the bundles individually distinct.

6. A sheet according to any of the preceding claims in which the elastomer is a

polyurethane.

7. A sheet according to any of the preceding claims in which the fibrous structure is a non-woven fabric structure.

8. A sheet according to any of the preceding claims in which a total of from 15 to 70 parts by weight of the cured organic polymer and the elastomer are present based on 100 parts by weight of the sheet after impregnation.

9. A sheet according to any of the preceding claims in which from 0.5 to 50 parts by weight of the cured organic polymer are present per 100 parts by weight of the elastomer.

10. A sheet according to any of the preceding claims in which from 0.5 to 20 parts by weight of the cured organic polymer are present per 100 parts by weight of the elastomer.

11. A sheet according to any of the preceding claims in which, in addition to the cured organic polymer and the elastomer, there is also incorporated a self-crosslinked acrylic resin emulsion or cured silicone liquid or emulsion.

12. A napped bonded fibrous sheet comprising a fabric layer with naps on a surface thereof according to the invention and substantially as described in any one of the Examples.

13. A process for preparing a sheet as claimed in claim 1 which comprises applying a curable organic polymer to a fibrous structure, comprising fibre bundle units, curing the polymer, subsequently applying an elastomer and thereafter buffing and/or raising the structure to form a fabric layer with naps on a surface thereof.

14. A process according to claim 13 in which the fibrous structure is composed mainly of bundles of superfine fibres of less than 0.7 denier.

15. A process according to claim 14 in which the bundles of superfine fibres are obtained by removing the sea component from an "islands-in-a-sea" type composite fibre.

16. A process according to claim 15, in which the island component of the "islands-in-a-sea" type composite fibre is a polyester or a polymer of the polyesterether series and the sea component of the fibre is a polymer of the polystyrene series.

17. A process according to any of claims 13 to 16 in which the curable organic polymer is a polyorganosilicone.

IS. A process according to claim 17, in which the polyorganosilicone is silicone rubber-forming polyorganosiloxane.

19. A process according to claim 13, in which the elastomer is a polyurethane.

20. A process according to any of claims 13 to 19 in which the fibrous structure is a non-woven fabric structure.

21. A process according to any of claims 13 to 20 in which, in addition to the curable organic polymer and elastomer there is incorporated a self-crosslinking type acrylic resin emulsion or a curable silicone liquid or emulsion either before or after buffing and/or raising.

22. A process according to any of the preceding claims 13 to 21 which comprise applying a water-soluble sizing agent to the fibrous structure before applying curable organic polymer and removing the sizing agent after applying the elastomer.

23. A process according to claims 22 and 15 in which the sea component is removed after applying the sizing agent, but before applying the curable organic polymer.

24. A process for preparing a sheet as claimed in claim 1 which comprises preparing a web using a predominant amount of an "islands-in-a-sea" type composite fibre which becomes a bundle of superfine fibres when the sea component is removed therefrom, needle punching said web to obtain a non-woven fibrous structure, applying a sizing agent to the non-woven fibreous structure which sizing agent is soluble in cold water or hot water and not easily removable in the subsequent step of removing the sea component so as to fix the shape of the sheet, removing the sea component of the composite fibre, applying a silicone rubber-forming polyorganosiloxane to the resultant sheet, curing the siloxane, thereafter, applying polyurethane to the resultant sheet removing the sizing agent, slicing said fabric and thereafter buffing and/or raising at least one surface of the resultant sheet to form naps.

25. A process for preparing a sheet according to the invention substantially as described in any one of the Examples.