EP0286767A1 - Method and apparatus for continuously applying a liquid to an absorbant compressible sheet-like material web - Google Patents

Abstract

A process and an apparatus for the continuous and controlled application of liquor on an absorptive, compressible material web such as textile webs, warp yarn layers or fleeces. One or more liquors are applied in amounts being comprised between the values of water retention capacity and saturation. The liquor containing web is passed through an equalizing device wherein the web is drawn through an equalizing nip or slit whose thickness is adjustable and smaller than the thickness of the incoming, liquor containing material web. The equalizing may be effected in the nip of two rollers. The liquor concentration in the web before and after the equalizing is statistically the same.

Description

The invention relates to a method for the continuous application of liquor, preferably of finishing liquor, to absorbent and compressible material webs, in particular fiber webs, e.g. Textile webs. It also relates to devices for carrying out the method.

The following explanations refer to the mostly present case of textile fiber materials. They also apply analogously to other absorbent, compressible webs, e.g. certain papers, sponge material, synthetic and natural fiber fleeces, etc.

The present invention relates to a method in which such an amount of liquor is applied all at once or in succession that the maximum determined by the absorbency of the substrate absorbable amount is not reached, but the total amount applied is above the water retention capacity of the substrate. Methods in which the maximum achievable amount is applied and the excess is removed again, in particular padding, are not part of the invention.

A whole series of methods and working methods are known in textile technology with the aid of which liquids (liquors) can be applied to textile material webs. The term "web" encompasses a textile structure capable of absorbing liquids, the length of which is very great in relation to the width, for example about 500 to 10,000 times, and with a thickness that is usually between one and about ten times the diameter of the threads that make up the textile. In addition to woven fabrics, the term therefore includes knitted fabrics, other nonwoven webs such as nonwovens and also sheets of parallel warp threads that are to be sized or, for example, dyed before weaving. In these cases, the thickness of the web can also be greater.

Examples of such processes include padding, splashing, the various methods of impregnation, spraying, spotting the liquor, applying foam and printing; in many cases it is necessary or inexpensive to first apply the excess and then remove the excess. An important example of the latter method is padding, in which the textile material web is basically offered as much liquor as it would like to take up, and the excess of liquor removed between squeeze rollers. It is not possible to remove more liquor than the so-called water retention value, which is determined according to the DIN 53'814 standard. At technically reasonable squeeze pressures, the remaining amount of liquor is above this limit. Without squeezing, the amount of liquor applied, also called pickup, cannot be regulated.

An important process for applying fleets, in particular finishing fleets, to textile goods webs has been the so-called "MA process" (MA stands for minimum order) since the 1970s, which allows uniform, regulated and excess orders to avoid impregnation of textile goods webs at high working speeds. It is e.g. in US-A 3 862 553 and 3 822 834 and does not require a squeeze mechanism. The minimum order is defined as the amount of liquor in% by weight that lies between zero and a value given by the expression (W² / 150) + 40, where W is the water retention capacity mentioned. The upper limit is 10 to 30% by weight below the limit of the squeezable excess. The process has become established worldwide, it is known to the person skilled in the art and it should not be necessary to list its advantages.

Although the process just mentioned has become known as the "minimum order" process, it can also be used to apply larger quantities of liquor than the actual minimum order in a regulated, uniform manner. Together with the minimum order, this alternative procedure is described below with the name "metering roller order". The metering rollers order accordingly includes all order quantities that lie between the value of W and the saturation value of the substrate.

The application of approximately 10 to 25% by weight of, in particular, aqueous liquors to a dry hydrophilic textile web, i.e. one which does not contain more than about 15% by weight of moisture is problem-free in that a uniform one-sided application is distributed sufficiently homogeneously in the textile material in a short time, owing to the capillary forces. But it can also happen with minimal application that particularly little fiber-affine or viscous liquors form an uneven or undesirable one-sided application.

In the case of higher order quantities, the time available for the web-shaped textile goods between the application unit and the dryer is sometimes insufficient to distribute the fleet, so that inhomogeneities can be observed. Similar phenomena occur when the web to be loaded with fleet already contains another fleet; in this case, the phenomena of the uneven liquor distribution are even more pronounced because the liquor distribution in the web material must be carried out primarily by liquid-liquid diffusion, which is significantly slower than a distribution in the capillaries.

A uniform liquor distribution in the cases just described has so far been achieved by dwell processes in which the web material is wound up and left to itself for a long time. Residence processes are expensive in terms of materials, space and capital.

Another way of uniformly distributing the liquor, which does not belong to the process group considered here, is padding. Other disadvantages of this method, in addition to the limited controllability of the application mentioned above, are the high and expensive outlay on equipment and the phenomenon that, in the case of webs which already contain fleets, the first liquor is squeezed together with the padded second liquor.

When sizing warp thread coulters, it has also already been proposed to pass the warp thread coulter provided with sizing, which forms a flat material web in the sense of the invention, through a roller crushing unit. If an equalization is achieved in this way, the squeezing is an uncontrollable process, and portions of the size that should remain in the warp thread family are usually squeezed out.

The invention has now set itself the goal of eliminating the disadvantages described above and to provide a method which makes it possible in a simple manner to distribute the liquors applied to a receptive web material uniformly therein, the distribution effect being controllable and no squeezing of fleet occurs.

In CH-A 530 230 it is mentioned casually that the even enforcement of the textile goods with the finishing fleet can be promoted in particularly unfavorable cases by special measures, including mechanical measures such as squeezing mechanisms. The cited reference is, however, only the minimum order, in which, in unfavorable cases of the distribution of the fleet, the use of squeeze units Can accelerate distribution. However, tests have shown that the uniformity of the distribution is a characteristic of the minimum order, and therefore the application of the squeeze units to the uniform distribution of fleet quantities which comprise a squeezable excess cannot be transferred.

Squeezers consist of a cooperating pair of rollers, in which at least one roller has a rubber-elastic surface or is made entirely of rubber. The material web is passed between the two rollers and clamped. A squeezing effect arises from the fact that the two rollers are pressed against one another, the elastic surface of the rubber roller flattening out and a squeezing effect being exerted thereby. A regulation of the squeezing effect is, analogous to the foulard, only possible within very narrow limits. It has been found that such a squeeze mechanism is not suitable for the purposes of the invention.

It has now surprisingly been found that in order to uniformly distribute the liquor in the material web, it is important to compress the material web, which is provided with the liquor and enters a leveling unit, by a certain amount to be determined, based on the state in front of the leveling unit, in order to achieve the target to achieve the invention, and that this amount is primarily a function of the liquor content of the material web, but also its structure, whereby this compression ratio must be controllable accordingly. It is clear that this finding cannot be achieved with a simple squeeze mechanism, which always has a relatively high, practical, uncontrollable squeeze effect.

The effect of the above-mentioned controllable compression is that only a redistribution of the liquor takes place inside the material web, in particular by bringing fibers or fiber areas which contain excess liquor quantities into intimate contact with those areas where there is a fleet deficit without that the fleet is squeezed out of the material web.

The method according to the invention now forms the subject of the first independent claim, and special configurations are defined in dependent claims. Devices which are particularly suitable for carrying out the method are claimed in further independent claims.

The invention represents a new, universal concept that provides a quick, uniform and controllable impregnation with liquor and can be followed by any application method, the uniformity of which is insufficient. The new process brings great advantages to spray technology, which is elegant in itself but always results in a non-uniform application. A preferred application of the invention is in connection with the metering roller application method.

The compression of the material web in the leveling unit is achieved in that the web is passed through a gap, the thickness of which is set between zero and the thickness of the web entering the leveling unit. The setting of the thickness of the gap depends on several factors, the goal always being the bare one Redistribution, ie equalization, of the fleet inside the material web must apply. The most important factors are the compressibility of the web containing the fleet, its thickness before it enters the leveling plant, and the content of the fleet. Other factors are the physical properties of the fleet and material web as well as the degree of non-uniformity of the fleet order.

In practice, it is not necessary to know all of these factors. It is mainly necessary to drive the leveling unit in such a way that in the long run no liquor is squeezed out at the leveling gap. A brief appearance of squeezed fleet is normal, because a partial fleet excess is part of the nature of the non-uniformity of the order. This short-term occurrence of expressed excesses can advantageously be used as a manipulated variable for regulating the gap thickness, as will be described further below.

It is usually necessary to measure the liquor quantities per unit area or weight of the material web in front of the leveling unit and to compare them with the target values so that the desired amount of liquor to be applied can be achieved in the material web and kept constant. A measuring point is sufficient for rough results, namely between the commissioning plant and the leveling plant; in this case the basis weight of the untreated web must be entered. More precise results can be obtained if you also continuously measure the data of the untreated web. You can also measure the weight of the material web after leveling, which provides a manipulated variable for regulating the effect of the leveling unit. This is described below.

The measurement of this data is known per se and can be done by radiation or wave absorption.

In the method according to the invention, the textile web to be impregnated is first conveyed, as usual, by a delivery plant. This consists either of two rolls with a nip through which the textile web is guided, at least one roll being driven, or of a driven roll with a non-slip surface which is wrapped around at least 180 °. The train then arrives at the fleet applicator either directly or via guide, balancing and / or spreading rollers.

The preferred fleet order unit, which can also be present twice or more, i.e. the metering roller application device is either the MA application device known from the above-mentioned US Pat. No. 3,862,553 or its new development, which forms the subject of EU-A-0137089. From the disclosure of these two publications, the construction of the devices and their functions as well as the operating method are apparent in every detail.

The method according to the invention can also be carried out with other application works which are known to the person skilled in the art. Foularding with squeezing of the excess fleet is out of the question. The selected order method can deliver an uneven order, but constant streaky unevenness over the length or width should be avoided.

The gap required in the leveling plant can be achieved in various ways. Usually the gap between two rollers is set by which one should be provided with a rubber-elastic surface or be made entirely of rubber. This roller is driven. The other roller should have a harder surface and can also be driven.

To adjust the nip, one roller is brought closer to the other. This is best done with a screw drive. Additional devices are preferably provided to quickly lift one roller from the other so that web tears are prevented when seams or other thick spots run in. This quick lifting can be effected by a hydraulically operated toggle lever mechanism, for example. Such constructions are known to the person skilled in the art.

It is advantageous if the hard roller is provided with heating or cooling means. Means can be provided to apply steam to the web from the outside in order to avoid liquor evaporation when the roller is heated.

The gap can also be formed by two solid surfaces, which face each other at a short distance and are preferably provided with an elastic covering, the surface of which has a low coefficient of friction.

Several leveling units can also be provided in succession.

In leveling units with rollers, these can be installed in any arrangement; the plane in which the two roller axes lie can therefore be horizontal, vertical or any inclination. The web can also wrap around one or both rollers at any angle.

After leaving the leveling unit, the material web is further processed as usual by generally transferring it to a continuously operating dryer, in particular a tenter. This is equipped in a known manner with the usual auxiliary devices. Finally, the web is wound up.

The invention now makes it possible to eliminate non-uniformities which have often been observed when using the known application methods and which have hitherto either been accepted or had to be avoided by using other, more complicated methods. In addition, two or more fleets can now be applied one after the other, which are not stable when mixed and are mixed and evenly distributed in the web material itself.

It also makes it possible to achieve a controlled, constant fleet order regardless of the speed of the goods.

In the drawing, special embodiments of the device according to the invention are shown as an example, which will now be discussed. Process details will also emerge from this description.

• FIG. 1 eine allgemeine Ausführungsform der Vorrichtung,
• FIG. 2 eine Variante der in FIG. 1 ge­zeigten Vorrichtung,
• FIG. 3 eine weitere Ausführungsform des Egalisierwerkes gemäss FIG. 1, und
• FIG. 4 eine Ausführungsform eines Teiles der Vorrichtung gemäss FIG. 1, wobei eine Dosierwalzen-Auftragsvorrichtung gezeigt ist.

In the drawing:

• FIG. 1 shows a general embodiment of the device,
• FIG. 2 a variant of the in FIG. 1 device shown,
• FIG. 3 shows a further embodiment of the leveling unit according to FIG. 1, and
• FIG. 4 shows an embodiment of a part of the device according to FIG. 1, wherein a metering roller application device is shown.

All figures are roughly schematic and are primarily intended to show the course of the textile goods and the individual device elements. The same reference numerals mean the same or functionally equivalent components.

A preferred embodiment of the device according to the invention is shown in FIG. 1 shown very schematically. Auxiliary devices such as circulation and feed pumps, fleet tanks, machine frames, motors, control and regulating devices are not shown or are not shown in detail; they are known to the person skilled in the art.

The device initially has a delivery mechanism, which is represented schematically by the roller 12. The supplied textile web 20, which comes from an edge 18, for example, wraps around the driven delivery roller 12, which is provided with a non-slip coating, at approximately 220 °. It then reaches the web tension compensation via a deflection roller 11 to a dancer roller 10. The web 20 passes through the measuring apparatus 28, 28ʹ measuring the web thickness without contact and indicating the square meter weight, and then it is optionally fed to a group of arch rollers 24 which are used to smooth the textile material and to the Spread out wrinkles. They are usually required for knitwear, but are usually not necessary for solid fabrics such as shirt fabrics.

The material web 20 then arrives at the application unit 22, which can be of any configuration and produces a more or less uniform controlled application of the liquor, the amount of which is between the value of the water retention capacity of the substrate, determined according to DIN 53,814 (according to ASTM-D2402-65T or SNV 98592 ), and the saturation value. A roller, foam or spray device, etc. be.

The device 22 can also be present more than once if it is cheap or necessary to apply partial fleets, e.g. reactive dyeing.

The leveling unit 30, into which the material web 20 then runs, consists of two interacting rollers 32 and 34 driven at the same surface speed as those of the material web, the axes of which lie in the same vertical plane and have the same diameter. The upper roller 32 is mounted in a fixed position, while the lower roller 34, which has a rubber covering 35, can be raised and lowered using the pneumatic, hydraulic or electrical drive 36. The two rollers can of course also be interchanged.

There is also a fleet sensor 40 which projects into the free space in front of the nip 41 of the rollers 32, 34 and laterally from the web 20. It has the task of sensing current parts of the fleet, expressed as small beads, from the web. The Level sensor 40 can be of any design. For example, he can sense the level through surface contact, he can work on the basis of electrical, magnetoelectric (Hall effect) or reflective variables (light such as infrared or laser light, other rays such as beta or gamma rays, soft X-rays, corpuscular radiation). It is preferably constructed and arranged in such a way that it periodically senses across the width of the web 20, for example with a sampling frequency of a few Hertz. It is only essential that the sensor 40 delivers a signal that represents unambiguous information about the presence of liquid at any point in front of the nip 41.

The web 20 then passes into the dryer 46 and is rolled up on the roll 16.

Instead of a real material web 20, single or multi-layer thread sheets, e.g. Warp thread coulters are used.

Furthermore, adjusting and regulating devices are available to achieve the goal according to the invention. In the application control device 50 with the actuator 52, the amount of liquor to be applied by the application device 22 is set and kept constant. The necessary information about the basis weight of the material web comes via lines 54 and 56 from the basis weight measuring devices 28, 28, and 26, 26ʹ. These devices are known to the person skilled in the art and generally work on the basis of radiation absorption. The corresponding control commands go to the order unit 22 via the line 58.

The liquid detector 40 supplies a measurement signal via line 62 to the leveling control device 60, which gives a control command to the motor 36 for the roller adjustment via line 64. The control units 50 and 60 can be connected to one another.

The roller 32 can be equipped with heating or cooling devices; this is indicated by the snake 33. Furthermore, a steam hood 37 can be provided, through which water vapor can be introduced into the space above the roller 32.

The lifting and lowering motor 36 is set up in such a way that it can lift the roller 34 such that a gap 41 of a defined thickness is formed with the roller 32. In addition, a possibility, not shown, is provided for lowering the roller 34 very quickly by approximately 5 mm. This is necessary when the additionally available, optionally contactless, thickness sensor 82, which is connected to the control unit 60 via the line 84, detects a thick point in the web 20. The thick point can then pass through the enlarged nip 41 without the risk of a web break.

FIG. 2 shows another embodiment of the leveling unit in a very schematic side view. The two leveling rollers 32 and 34, the latter with the rubber layer 35, lie in the same horizontal plane. The servomotor 36 adjusts the gap width by moving the roller 34 horizontally, so that no precautions need to be taken to neutralize the weight of the roller.

Finally, FIG. 3 also schematically shows an embodiment with a roller-free leveling gap. It is formed between a fixed shaped piece 32A and a movable shaped piece 34 which is pivotable about the axis 39 and whose active surface, which comes into contact with the material web 20, is covered with a rubber layer 35. All surfaces over which the web 20 runs are provided with an anti-friction coating. The leveling gap is located in the lower region of the shaped pieces 32A, 34A.

In FIG. 4 schematically shows a preferred application unit 22, namely the already mentioned metering roller device, in a side view.

The metering roller device used here is a development of the applicant and is described and shown in detail in EP-A 0 137 089. This description is therefore not intended to be repeated completely here.

The metering roller 72 is immersed in a trough 70, which is partially filled with liquor, and is driven in the direction of the arrow shown. The material web 20 is guided grazing over the surface of the metering roller 72; in general, the speed of the web is greater than the peripheral speed of the metering roller 72.

A lowerable, drivable counter roller 78 is arranged above and shortly before the metering roller 72, viewed in the direction of web travel.

This tangential roller 78, which is covered with rubber, can be moved by means of the motor 80 in the direction of the Adjust the surface of the metering roller 72 and in the opposite direction. It is used to open the material web and to transfer it to the metering roller in a bound manner. Roll gaps can be set which are smaller than the normal thickness of the material web. This gives, among other things, a more precise removal of the liquor film brought up by the metering roll. The doctor blade 74 and 76 are used to clean the metering roller.

The control drive 59 of the metering roller, the peripheral speed of which determines the amount of liquor that can be applied in the unit of time, is connected to the control unit 50 by line 58.

The system works as follows:

The fleet application applied to the web 20 is continuously monitored as the difference between the measured values of the sensors 28, 28ʹ and 26, 26ʹ. Appropriate sensor designs ensure that the measured values are constantly averaged across the width of the web in order to compensate for non-uniformities in the job. If the actual value of the job exceeds or falls below the target value set on the actuator 52, the controller 50 ensures that appropriate correction.

The material web 20 impregnated with liquor is guided around the upper roller 32 of the leveling unit and into the gap 41 with the lower leveling roller 34. It then enters dryer 46, e.g. a stenter, and is finally rolled up on the edge 16.

The thickness of the nip 41 is set by the servomotor 36 to the predetermined one in the Control device 60 is set for the respective substrate and the amount of liquor stored, empirically determined value. The control unit 60 then takes care of this. that the thickness of the nip is gradually reduced until the first small portions of liquor emerge in front of the nip 41 due to the constantly increased compression of the material web and do not immediately disappear again. This state is sensed by the liquid detector 40 and reported to the control unit 60, which causes a slight increase in the thickness of the nip. The brief appearance and disappearance of emerging fleet parts indicates the optimal operation of the equalization.

If there are no expressed fleet shares, this is an order with a non-crushable fleet pad. This is communicated to the control unit 60 by the job controller 50. In this case, the motor 36 is caused to set the gap thickness to a fixed value which is programmed in and is, for example, 60 or 80% of the material web thickness. With a few trials, it is possible to determine empirically what is the optimal thickness of the gap for leveling. When it comes to distributing more viscous or substrate-less fleets, heating is beneficial. For this purpose, the roller 32 is designed to be heatable. So that no liquor solvent evaporates when the material web is heated, steam or a steam-air mixture can be blown onto the material web simultaneously through the hood 37.

The device according to the invention and also the method can be modified and modified within the scope of the stress be modified. For example, the motor 36, which determines the position of the pressure roller 34 of the leveling unit, can act on the roller adjustment by means of a translation for the purpose of even finer adjustment. A dwell section (not shown) can also be switched on, for example, between the application unit 22 and the leveling unit 30.

The material of the rollers of the leveling unit should be resilient, one roller being harder than the other. Usually a steel roller works against a rubber roller. Sponge rubber pads on the rollers have also proven to be suitable.

The device according to the invention allows, for example, the following finishing processes to be carried out on textile goods, the composition of the required liquors being known to the person skilled in the art:

Non-iron equipment,
Mooring,
Stiffen,
Dyeing, in particular pigment dyeing and reactive dyeing and thermosol dyeing,
Finishing, including warp thread finishing,
To make something soft,
Making hydrophobic,
Mooring water drops,
Mooring rotting,
Making it dirt-repellent,
Making oleophobic,
Crease resistant equipment,
Glossy equipment (chintz),
Flame retardant equipment,
Antistatic equipment,
Freeing of felt,
Moth-proof equipment,
Carbonize,
Decating,
Equip effects.

These can be liquors with aqueous, aqueous / organic or even purely organic solvents or dispersing agents.

Claims (17)

1. - Process for the continuous, controlled application of liquor to an absorbent, compressible material web, in which at least one liquor is applied in amounts which lie between the value of the water absorption capacity and the saturation value of the material web, characterized in that the material web containing the liquor is in one Leveling unit is directed in which the material web is temporarily compressed in a gap to a predetermined, controllable thickness, which is smaller than the thickness of the material web in front of the leveling unit, and that in the leveling unit, neither liquor is fed nor removed from the material web, such that the The amount of liquor in the material web before and after the leveling unit is essentially the same. 2. - The method according to claim 1, characterized in that the fleet is applied as a total fleet or successively as two or more sub-fleets. 3. - Method according to claim 1 or 2, characterized in that the amount of liquor in the material web is determined in front of the leveling unit. 4. - Method according to claim 1 or 2, characterized in that the amount of liquor applied to the material web is determined by determining the basis weights of the material web before and after each order, that the actual value obtained in this way is compared with a target value and the order quantity is readjusted, until the actual value and the setpoint match. 5. Method according to claim 4, characterized in that the measured values of the grammages are continuously averaged over the width of the material web. 6. - The method according to one or more of the preceding claims, characterized in that the gap in the leveling against a first, stationary roller is kept constant by controllable approaching or removal of an adjustable roller against a second, stationary roller, with at least one roller rotating is driven. 7. - Method according to one or more of the preceding claims, characterized in that the gap in the leveling unit is set to a value which is between almost zero and the thickness of the web-laden material web entering the leveling unit. 8. - The method according to claim 7, characterized in that while the web of material is running, the gap width is set and regulated in such a way that first liquor portions leave the material web in front of the gap, and that the gap width is then increased to such an extent that these liquor portions just disappear again . 9.- Device for the continuous, controlled application of liquor to an absorbent, compressible material web, with a web unwind, a conveyor for the material web, with at least one fleet application unit, a web dryer and a web winder, characterized in that after the or the last fleet application unit , in the direction of web travel seen, at least one leveling unit is arranged for the liquor content of the web, which, as an equalizing component, has a gap formed between two fixed or movable surfaces, one surface being adjustable against the other surface for the purpose of adjusting and regulating the gap thickness. 10. - Device according to claim 9, characterized in that two rollers are arranged in the leveling unit, at least one of which is driven, and that one roller is adjustably mounted against the other and the rollers together form the leveling gap. 11. - Device according to claim 9, characterized in that two shaped pieces are arranged in the leveling unit, the mutually facing inner surfaces of which approach in the direction of travel of the material web with formation of the leveling gap, that one shaped piece is fixed in place and the other is movable against the first shaped piece, whereby the gap thickness is adjustable and that all surfaces that come into contact with the material web are provided with a friction-reducing coating. 12. - Device according to claim 9, characterized in that in front of the leveling gap, seen in the direction of material, a liquid sensor is attached, which is set up for periodic scanning of the state in front of the gap across the width of the gap. 13. - Device according to claim 9, characterized in that the gap thickness between almost zero and the maximum thickness of the material web entering the leveling unit is adjustable and adjustable. 14. - Device according to claim 10, characterized in that the one roller is provided with means for heating or cooling. 15. - Device according to claim 12, characterized in that a control device is provided with which the liquid sensor and the actuator of the movable one gap surface are connected. 16. - Device according to one of claims 9 to 15, characterized in that there are two organs for measuring the basis weight of the material web, one of which is arranged in front of the liquor applicator and the other after the liquor applicator. 17. - Device according to one of claims 9 to 16, characterized in that a series of spreading and spreading rollers for the material web is arranged in front of the fleet applicator.

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