NO137559B - DEVICE FOR USE WHEN STRESSING SCREWS, FREE-HELDING CONCRETE HOLE PILLARS - Google Patents

Description

Procedure for binding fibers in textile materials.

The present invention relates to a

method for binding the fibers in textile materials, in particular a method for supplying atomized substances to yarns and fabrics.

A number of methods have been proposed to provide a binding of the fibers in fabrics, including the use of solvents for the fibers. These liquid binder solutions are normally added to the fabric by being brushed onto the surface of the fabric. If this method is used for fabrics, where a significant part of the thickness is made up of surface fibers which are held firmly in the fabric structure with one end and have the other end essentially free on the surface, the fibers will be bound to each other quite arbitrarily, so that the fabric's appearance and other characteristics are reduced to a serious extent. The thickness of the surface fibers is also significantly reduced if these fixing solutions are brushed on or applied by spraying under high pressure.

The object of the present invention

is to provide a method which gives textile materials improved properties by attaching surface fibers with one free end. The purpose is in particular to reduce pilling and surface damage on roughed fabrics without increasing stiffness, particularly for fabrics where the surface fibers have been produced from an artificial, filament-like material.

The invention provides a method for binding the fibers in a textile material, preferably of acrylonitrile polymers, by spraying on the material finely divided particles of a fiber dissolving agent. The method is distinguished by the fact that the liquid particles, which consist of about 1-8 percent by weight of a latent fiber solvent in an inert volatile liquid diluent, have a diameter smaller than 0.3 mm and are deposited on a fluffed (roughened) textile material, such as a woolen carpet in the form of a mist, under such conditions that noticeable displacement or compression of the fibers is avoided, after which the fiber solvent is activated by evaporating the diluent. The atomized liquid particles can advantageously be added at room temperature, after which the textile fabric is heated, so that the volatile diluents are removed and the latent fiber solvent is activated.

The method is particularly suitable for treating textile materials containing fibers made from acrylonitrile polymer. These materials are preferably treated with a mist of liquid particles comprising from 4 to 6% sodium thiocyanate in an aqueous solution. When sodium thiocyanate is used as a latent fiber solvent for fixing the acrylonitrile fibres, the amount (dry weight) of thiocyanate salt that settles on the cloth will be between 0.02 and 0.15 g/0.8 m<2> of the cloth's surface. The best properties in terms of the fabric's stiffness are obtained when this amount is between 0.1 and 0.13 g.

By the expression "latent fiber dissolving agent" is meant in this connection any liquid or any solid substance which is soluble in or can be mixed with the volatile liquid diluent which in the first one-phase liquid solution cannot dissolve the fibers, but which after activation of the latent solvent e.g. upon evaporation of the diluent, is able to attach these (ie at least make the surfaces of the fibers sticky). The amount of fiber solvent in the volatile liquid diluent is calculated on an undiluted or dry weight basis. In this connection, the fiber solvent can be dissolved in a separate liquid solvent or, as indicated, it can be used alone in the liquid diluent.

A woven carpet consisting of 100% polyacrylonitrile fibers which are distributed in the carpet in such a way that approx. 25% of its total thickness lies in the middle and 75% of the total thickness is formed by roughing (loing) on the carpet's two surfaces, was advantageously treated in the following way: A suitable pre-powdered fabric for binding the carpet's fibers together was produced by aqueous solution containing 5% by weight of sodium thiocyanate by atomizing this solution in a device which will otherwise be described in connection with the following examples. The blanket was passed continuously over the top of the atomizing apparatus without it coming into contact with it, while small drops of the atomized liquid settled on one side of the blanket. The carpet was then passed directly through a 4.6 m long drying oven maintained at 149° C; the feed rate was 1.8 m/min. The fiber solvent was thereby made active by the diluent being evaporated, so that the fibers were bound to each other at a number of crossing points. In the oven, all thinner was also removed, so that the laundry was completely dry and had no tendency to stick. The dried cloth or carpet had taken up 0.07 g of sodium thiocyanate per 0.8 m<2> of the cloth's surface. This fabric, where the fibers had been attached to each other, had less tendency to pilling and the surface did not become uneven as easily as with similar non-treated fabrics.

Although the stiffness of the treated fabric is directly dependent on the amount of fiber solvent taken up by the surface of the fabric, it is surprising that the resistance to surface roughness and pilling is not. The two last-mentioned properties depend on the concentration of the latent fiber dissolving agent in the liquid solution that is atomised. In order to obtain fabrics which, after the treatment, have the desired stiffness properties and resistance to pilling, it has been found that the critical values when carrying out the method lie between 1 and 8 percent by weight of the total weight of the solution.

Another critical factor is the size of the separated liquid particles that are added to the textile material in atomized form. The maximum size of these liquid particles consisting of liquid fiber solvent and diluent is approx. 0.305 mm. If these particles become a good deal larger than the critical maximum value stated, the fabrics, when treated, will lose their good appearance, they will become stiff to an undesirable degree at the same time as the fluff loses a good part of its thickness. A number of devices capable of forming liquid particles of less than 0.305 mm in size are available for purchase, e.g. humidifying devices, atomizing mouthpieces, atomizing devices, spraying devices and the like. An apparatus that is particularly suitable in this connection is one that atomizes the liquid into a fine dust and is described in US patents 2,022,415 and 2,591,057. This type of humidifying apparatus produces a mist of liquid particles that lie within a large size range. The large, heavy particles that are not suitable for application to the laundry hit the walls of the dampening device, coalesce and flow back into a tank, so that none of the large liquid particles can come into contact with the fibers or the laundry being treated, as that only a portion of the smaller particles reach the laundry. The small liquid particles in the fog are essentially round.

Another important limitation of the present invention is formed by the conditions that should prevail when the mist is supplied to the textile material. The atomized liquid must be applied to the surface of the yarn, cloth or textile material to be treated, without it being exposed to mechanical compression forces, e.g. such as would occur if a roller or an ironing device were used. Furthermore, the particles must not be fed into the textile material at such a high speed that they will in any way compress the fibres. A number of the previously constructed spray devices will therefore be unsuitable, as the air and/or liquid pressure produced in the nozzle of the spray device will be so great that the surface fibers of the textile material are pressed together, so that the thickness of the fleece and other desired properties are reduced at the same time . These high pressures will also cause the fiber solvent to be supplied unevenly across the width of the fabric, so that it does not have completely uniform properties and so that it becomes difficult or impossible to produce several fabrics with the same properties.

The atomized material is normally supplied to the textile material at room temperature, but it is also possible to increase the temperature of the mist or the cloth as long as the temperature is well below that which transforms the latent fiber solvent into an active fiber solvent. A temperature range which is suitable for drying and fixing polyacrylonitrile fibers is from 102 to 176° C, preferably from 121 to 159° C, which temperature prevails for 1 to 5 min. The temperature of the mist and the drying and binding temperatures must of course not be so high that the textile material's surface fibers melt or deform to such an extent that the fiber character is destroyed.

Typical fiber solvents that can be used for acrylonitrile polymer fibers include aqueous solutions of sodium thiocyanate, lithium thiocyanate, lithium iodide, sodium iodide, calcium thiocyanate, potassium thiocyanate, calcium bromide, zinc chloride, lithium bromide, magnesium thiocyanate, cupric chloride, magnesium chloride, ferric chloride, ferrous bromide, cadmium iodide, barium chloride and cobalt iodide. Suitable fiber solvents also include propylene carbonate, ethylene carbonate, dimethylsulfone, tetramethylenesulfone, dimethylformamide, dimethylacetamide, gamma-butyrolactone, trimethylene carbonate and the like. These can be dissolved in water and many of them can be dissolved in alcohol, ethylene glycol, benzene or the like. Typical fiber solvents for polyamide fibers are aqueous solutions of the inorganic salts stated above for the acrylonitrile polymer fibers as well as other substances such as e.g. nitric acid, formic acid, phenol, meta-cresol and the like. These can be dissolved in water, ethanol, methanol, benzene and the like depending on the fiber solvent used. Typical fiber solvents for polyester fibers are benzyl alcohol, benzoic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, dichlorophenol and aqueous solutions of calcium and magnesium thiocyanate. Known solvents for other polymers listed below may similarly be used when such polymers are present. In the case of natural fibers etc, any known solvent can be used. Typical solvents suitable for wool are alkali metal salts of thioglycol acid and sodium sulphide. Dilute, aqueous solutions of ferric chloride and the like can be used for rayon.

The volatile, liquid dilute

The solvent used in the preparation of the single-phase solution according to the invention can, if desired, be the same liquid that is used for dissolving the fiber solvent, as indicated above in the list of fiber solvents, or the diluent can consist of another liquid that can be mixed with the liquid used to dissolve the fiber dissolving agent. The diluent can be aqueous or organic or a mixture of two or more liquids that can be mixed with each other. In any case, the diluent should be able to dissolve the fiber solvent, so that a single-phase liquid solution is formed. The diluent should be relatively inert in relation to the material's fibers.

Although the liquid solution will normally consist of only two ingredients (i.e. the latent fiber solvent and the diluent), it may be appropriate when treating certain textile materials to use smaller amounts of inert stretching agents in the solution (e.g. polyethylene oxide), softeners , antistatic agents, smoothing agents, pigments and dyes as well as other substances that can be dissolved or dispersed in the solution to achieve special results. However, these additives must be chosen carefully both with regard to quantity and composition, so that the joint effect of the two main ingredients is not destroyed by the spraying, application and treatment of the textile material.

The textile materials that can be treated according to the method according to the invention include ribbon, tow, yarn, warp, "batts" and woven, knitted and non-woven fabrics. The woven fabrics can e.g. consist of flannels spun with carded yarn or worsted yarn, tweed fabrics, Shetland fabrics, woolen carpets, floor carpets, plush fabrics and the like. The knitted items can e.g. be warp-knitted or circular-knitted jackets, jumpers, pullovers, plush clothes, stockings and hosiery, suits, gloves, scarves and the like. The non-woven items can e.g. be carpets, saddler's clothes, woolen items, furs, flannel clothes, pullovers, filters, hats and the like.

The composition of the individual fibers and/or the interconnected threads of which the textile material is made up should, in order to achieve benefits from the treatment according to the invention, contain at least 25 percent by weight of an organic polymer

fiber material that has the property that the threads can be tied to each other. Blendin-

gers of synthetic and/or natural fibers can advantageously undergo the treatment if all the fibers are to be bonded together, or the solutions can be chosen so that they do not affect the fibers that are not to be bonded.

Typical synthetic organic fibers and threads that can be treated by the method according to the invention include those produced from polyamides such as e.g. poly(hexamethylene adipamide), poly(hexamethylene sebacamide), polycaproamide and co-polyamides, polyesters and copolyesters such as e.g. condensation products of ethylene glycol with teraphthalic acid, ethylene glycol with a 90/10 mixture of teraphthalic/isophthalic acid, ethylene glycol with a 98/2 mixture of teraphthalic/5-(sodium sulfo)-isophthalic acids and trans-p-hexahydroxylylene glycol with terephthalic acid, polyacrylonitrile, copolymer of acrylonitrile with other monomers such as vinyl acetate, vinyl chloride, methyl acrylate, vinyl pyridine, sodium styrene sulfonate, terpolymer of acrylonitrile/methyl acrylate/sodium styrene sulfonate, vinyl and vinylidene polymer and copolymer, polycarbonates, polyurethanes, polyesteramides, polyethylenes, polypropylenes , fluorinated ethylene polymers and copolymers, cellulose derivatives such as cellulose acetate, cellulose triacetate, rayon and viscose, mixed threads such as e.g. a layer of polyamides around a core of polyester or two acrylonitrile polymers differing in ionizable group content and spun as a layer and a core as described in French Patent No. 1 205 162. The fibers may be shrunk or unshrunk, stretched or not stretched, and/or crumpled or not crumpled.

The greatest advantage of the invention is that a new and better method is obtained by binding the fibers in textile materials, especially the loose surface fibers. When treating e.g. pullovers made from acrylic fibres, there is a significant reduction in pilling. Another advantage is that the invention provides a method for producing woolen carpets with resistance to damage on the surface and high compression resistance, without the appearance suffering in any way and without the piled part of the woolen carpet becoming thinner. Another advantage is that the pile formation and straw formations on yarns and fabrics can be reduced without the stiffness being affected to a greater extent. The method also reduces straw formations and sticking in non-woven fabrics. Further advantages are that the method can produce woolen carpets that have an increased resistance to surface damage during repeated washings, and that fabrics with greater coverage and uniformity can be produced than fabrics where the fibers have not been bound.

The following tests were carried out to measure the properties indicated in the following table. The amount of sodium thiocyanate that was deposited per 0.8 m of the cloth's surface was determined by colorimetric tests where an excess of ferric ions was used according to a method set out on page 485 of Scotf's "Standard Methods of Chemical Analysis", 5th edition.

The durability of the appearance was measured with a test apparatus consisting of a device that rubbed a part of the cloth against itself in a circular turning motion under a standard load. This test device was purchased from

"Fabric Development Tests, P.O. Box 45, Brooklyn 32, New York" and is described by Jack J. Press in an article entitled "The Development of a Pilling Test for Apparel Fabrics", in "Papers of the American Association For Textile Technology", page 19 — 33, December 1953. The figures given in

the tables for the durability of appearance show that the pieces of cloth that were examined in the apparatus were classified from 1 (the surface fibers destroyed or disturbed to a large extent) to 5 (perfect without any visible sign of disturbance of the surface fibers).

The subjective stiffness grades given in table 1 were given by five people who compared the different fiber materials with each other with regard to the relative stiffness, with a lower number indicating less stiffness. These numbers vary from 1 for a control piece of fabric up to 5, which is the stiffest of the fabrics indicated in the table.

The stiffness indicated in Table II is a quantitative measure of the stiffness of the cloth pieces;

the pieces of cloth were first placed in an air-filled room and were kept at room temperature for a period of at least 10 hours. A modified "Monsanto Wrinkle Recovery Test" was used in the test. A cloth band with a width of 1.4 cm was tensioned in a horizontal position and so that the band went 2.54 cm outside the fixed tension arrangement, after which the vertical deflection of the free end of the cloth was measured in mm, so that the less the cloth bent the higher was its stiffness. ~

Example 1:

A woven roughened (fuzzy) blanket made of 100% polyacrylonitrile fibers was passed horizontally through a fine mist of liquid particles moving vertically from the top of an atomizer. This nebulizer was purchased as Model No. OTVT "Web-Wetter" from Walton Laboratories, Inc., Irvington, New Jersey, U.S.A. The atomizer was fed continuously through a feed tube from a container containing an aqueous solution of sodium thiocyanate of the concentration indicated in Table I. The velocity of the fabric as it passed through the vertical column of atomized particles was varied so that the amount of sodium thiocyanate which was placed on the cloth, became different. After the laundry had passed through the mist, it was taken directly to an air-drying oven at a temperature of 121°C, in which it remained for 5 min. Special precautions were taken when treating the laundry with the atomized liquid, so that none of the laundry's surfaces were pressed together. The treated cloths were subjected to tests and the results are given in Table I. It appears from the table that the lower concentrations of sodium thiocyanate improve the durability of the appearance compared to the control piece, but 4% gives the best result of all the tests carried out in this series with consideration of the characteristics of the appearance. The amount of sodium thiocyanate that was placed on the cloth did not affect the durability of the appearance to any great extent, but increased the stiffness of the cloth. In example 5, where the laundry contained 0.110 g of thiocyanate per 0.8 m-, the stiffness of a carpet is still within the acceptable ranges.

Example 2:

A piece of the same woven pile carpet made from 100% polyacrylonitrile fibers used in Example 1 was treated in the same manner as in Example 1 while using different concentrations of the sodium thiocyanate solution. The treated fabric was tested and the properties obtained are listed in Table II and compared with a control piece that was not treated with the binding solution. The results in Table II show that the concentration of sodium thiocyanate in the solution is critical if it is to be achieved fabrics with satisfactory properties. It thus appears that a solution containing as much as 10% sodium thiocyanate gives a cloth which has a sticky surface and which therefore cannot be used as a carpet, even if the surface durability is satisfactory. It also appears that in the case of test pieces no. 1 and 2, which received approx. 0.1 g sodium thiocyanate per 0.8 m of the fabric's surface, a satisfactory stiffness and a dry surface was achieved, while sample 3 with 0.375 g of sodium thiocyanate per 0.8 m<2> of the cloth's surface was too stiff to be used as a carpet, even though the durability of the appearance was very satisfactory.

The invention has been described in connection with the treatment of a roughened poly-acrylonitrile carpet, but similar methods can be used when supplying

a mist containing a known solvent for textile materials is prepared

of any other polymer which

can be bound by adding a liquid which

does not have any significant binding effect on the polymer at room temperature, but which

can be activated by being heated, like this

that the polymeric fibers bind at the contact points where a small drop of the dust hits

settle down, and where the solvent then

can be removed, so that the fibers are intertwined

tied pointwise.

Claims (5)

1. Procedure for binding fibres in a textile material, preferably of acryl-nitrile polymers, by spraying on the material finely divided particles of a fiber dissolving agent, characterized in that the liquid particles, which consist of about 1-8 percent by weight of a latent fiber dissolving agent in an inert volatile liquid diluent, have a diameter smaller than 0.3 mm and is deposited on a fluffy (roughened) textile material, such as a woolen blanket in the form of a fog under such conditions that there noticeable displacement or compression of the fibers is avoided, after which the fiber solvent is activated by the diluent evaporating. 2. Method according to claim 1, characterized in that the liquid particles consist of a 4 to 6% water solution of sodium thiocyanate. 3. Method according to claim 1 or 2, characterized in that the treated material is a cloth containing from 0.02 to 0.15 g of solvent per 0.8 m'- of the cloth's surface. 4. Method according to claims 1-3, characterized in that the latent fiber solvent is activated by treating the textile material at a temperature of between 102 and 176°C. 5. Method according to claim 4, characterized in that the treated textile material is heated to a temperature of between 121° C and 159° C for a time of between 1 and 5 min.