RU2387746C2 - Method for production of non-woven materials, in particular soft, resistant and attractive - Google Patents

Abstract

FIELD: textile industry.

SUBSTANCE: method for production of non-woven material from single-layer or multi-layer sheet of non-woven material by means of this sheet processing at the stages of hydraulic and stamping impression, besides mentioned stages of impression are applied in any order. Besides two specified various impression stages are executed on specified sheet of non-woven material at various dedicated sections.

EFFECT: production of article on the basis of non-woven material, which has optimal characteristics of softness and stability in use.

33 cl, 7 dwg

Description

The present invention relates to a method and equipment for the manufacture of non-woven material having optimal softness and durability, as well as visually attractive. In particular, the invention relates to a method and equipment for the manufacture of non-woven materials from spun fibers (non-woven materials woven hydraulically) and non-woven materials obtained with their help.

Nonwoven fabric products having various characteristics suitable for specific purposes have been known for a long time. For example, products are known, in particular based on soft nonwoven material for use in personal care, such as wet wipes. Other products made of nonwoven materials are either dry or impregnated with substances with various properties, which are particularly resistant for use in the field of home cleaning or on an industrial level.

Products currently available on the market are distinguished from each other by specific properties obtained through various structures and processing to meet different usage requirements.

The technical problem underlying the present invention is to obtain a method of manufacturing a product based on non-woven material, which has optimal softness and at the same time optimal durability for use in personal hygiene and in the field of home cleaning.

This problem is solved using a method of manufacturing a nonwoven material, as claimed in the independent paragraph attached below.

Another technical problem that has been solved in accordance with the present invention is to obtain a method and installation for the manufacture of non-woven materials, such as those described above, containing signs and / or patterns printed on them in a reliable and fast manner, to obtain a printing process that provides a cost-effective performance.

This problem is solved using the method and production plant, as stated in the attached claims below.

Other characteristics and advantages of the present invention will be better understood from the following description of some embodiments of the invention, which are given as non-limiting examples with reference to the drawings, in which:

figure 1 is a schematic view of a production line for a nonwoven material in accordance with the present invention;

figure 2 is a schematic view of the production line shown in figure 1, corresponding to the first embodiment of the invention;

figa is a schematic view of the production line shown in figure 1, corresponding to the second variant embodiment of the invention;

figv is a schematic top view of the support part for a nonwoven material with sensitive elements for alignment;

figure 4 is a schematic view of the production line shown in figure 1, corresponding to the third variant embodiment of the invention;

5 is a schematic view of the production line shown in figure 1, corresponding to the fourth variant embodiment of the invention;

6 is a block diagram of a control unit and commands for the production line corresponding to the invention.

Thus, the first object of the present invention is to provide a method of manufacturing a non-woven material suitable for imparting softness / hairiness, as well as durability characteristics.

The second object is to obtain equipment for the production of non-woven material with the specified characteristics.

The third object is to obtain a non-woven material having the specified characteristics of softness / hairiness, as well as resistance for use as a product for personal hygiene and home cleaning.

It has been unexpectedly discovered that to solve the above technical problem, the nonwoven material can be subjected to a treatment comprising a hot stamping process and a thermal stamping process, in other words, the nonwoven material is treated by embossing according to two different methods known in the art.

In particular, hydrotreating treatment allows to obtain an article having optimal softness characteristics. In addition, the non-woven material processed using this technology simultaneously creates patterns and / or characters also in relief, with a visual effect of subtle shading, thus creating a soft feeling for both the eyes and the touch, and provides a sense of “depth” rather than "prospects." These tactile and visual characteristics are provided by equipment containing one or more items consisting of many very thin nozzles supplying high-pressure water jets. Preferably, the nozzles are arranged to create the desired characters or pattern.

After this treatment, the non-woven fabric is processed in such a way as to interlace the fibers with each other, which is done leaving them free to move relative to each other to create the desired softness effect.

Thermal embossing differs from the aforementioned treatment in that it allows imparting nonwoven material resistance characteristics by creating fiber bonding points that crosslink them. In particular, the fibers are welded to each other by heating and chopping in such a way that their movement relative to each other is prevented, thereby ensuring density and durability.

In addition, the product may also be decorated with signs or patterns during this processing. In fact, thermal stamping is performed using conventional thermal stamping calendars, where the nonwoven web is passed through two opposing cylinders. One or both of these cylinders is heated and has an engraved surface, usually made of metal, in such a way as to create the desired signs or patterns, while the other, usually rotatably pressed against the engraved cylinder and has a rubber or metal surface. As a result of this treatment by pressing and heating, strong bonding points are formed between the fibers, while obtaining explicit and clearly distinguishable signs or patterns.

The nonwoven fabric subjected to the process according to the invention may be spunlace type material, wherein the material that makes it up is either carded or spunbond type.

The carded material may essentially consist only of natural or synthetic fibers (between 0.9 and 7 denier), for example, polyester, polypropylene, PLA, rayon, LYOCELL ™, possibly mixed with each other, or specified fibers are combined with pulp. In addition, regardless of the material used, the nonwoven material may consist of one or more layers according to specific requirements or specific preferences. Preferably, the non-woven material consists of three layers, with a layer of pulp located between two layers of synthetic or natural fiber. The resulting product is usually called a multilayer nonwoven material, while the various layers are placed on top of each other according to the desired order and fastened to each other, that is, combined, completely in accordance with conventional technologies. Preferably, the combination is carried out by weaving hydraulically.

Spunbond material can essentially consist only of polymer fibers, such as polypropylene, polyester, PLA and LYOCELL ™ in the range between 0.9 and 2.2 denier or also nanofibres (NANOVAL) and also bicomponent fibers combined with cellulosic mass as described above. Also in this case, the deposition, composition and combination of the multilayer composition can be carried out using technologies known in this field, therefore, they will not be described here below.

Below will be described a method with reference to figure 1, corresponding to the invention, as well as exemplary equipment designed to implement this method.

A method of manufacturing a nonwoven material comprises two successive stages of various types of processing of the nonwoven fabric by any method selected from hydrotreating and heat stamping in any order.

In other words, the method may comprise a first step of hot stamping processing and a second step of thermal stamping processing, performed on a non-woven fabric, which can be either single-layer or multi-layer. Alternatively, the steps are reversed, that is, thermal embossing is the first processing step, and water embossing is the second processing step.

In Fig. 1, the hydrotreatment step is shown first, while it is carried out using technologies known in the art, as described above, at least on one equipment 1, 2. For example, the hydrotreatment treatment can be performed on the first equipment 1, where non-woven fabric W is served on the support roller 3, while the nozzle for hydraulic embossing are located on its circumference. Then, the nonwoven material W is fed on a flat base 4 under the second hydrofoil equipment 2 for possible further processing. The use of two types of equipment allows to achieve two different effects of hydraulic embossing (with tape and with a roll).

The wet non-woven material is then fed to a completely conventional dryer (heater) 5, such as a drum dryer.

Now, the nonwoven material W can either be wound on a bobbin and transferred to the intended production line for heat-stamping, or pass along the line to the heat-stamping step, as shown in FIG.

The thermal embossing step provides that the nonwoven fabric passes either on or without a suitable base through a conventional embossing calendar 6, where it is compressed and heated in such a way as to cause the fibers to bind at predetermined points, also in accordance with the signs and / or patterns, to be completed.

The non-woven material thus obtained predominantly has optimal softness and nap properties, being resistant to handling and wear. In particular, the non-woven fabric is effectively suitable for use with a delicate purpose for personal hygiene, and as a resistant fabric for home or industrial cleaning.

In addition, the hot stamping and thermal embossing treatments as described above can be performed in such a way as to combine these functional aspects with a noticeably attractive appearance and depth of field of view, since the hot stamping simulates an object close to the human eye and the hot stamping simulates an object far away on the horizon. In fact, thanks to a combination of the aforementioned technologies, muted and shaded three-dimensional patterns and / or signs can be obtained by hot stamping along with clearly visible and defined patterns and / or signs. An attractive appearance comes from the fact that a shading effect is created that creates a background and a clear image effect that creates a foreground.

It should be noted that according to the method described above, the effect of softness and fluffiness created by water embossing is superimposed on the effect of resistance and cohesion caused by heat embossing. In other words, the soft parts of the nonwoven fabric have some connected points, that is, in these parts the fibers of the nonwoven fabric have a relatively limited degree of freedom and movement. Therefore, despite providing a good combination of the desired technical characteristics, the resulting product has, however, a limited degree of softness.

In accordance with an embodiment of the method of the invention, the principle of increasing the softness of the nonwoven material without substantially changing the resistance and binding characteristics has been investigated.

It has been unexpectedly found that when the heat embossing treatment is carried out on parts not covered by the hot stamping treatment, the nonwoven material is significantly softer, while at the same time, the strength and durability remain substantially unchanged.

To this end, the development of a special method and equipment was required.

The production process contains a control system and commands connected to the controlled elements and devices of the processing points.

In particular, the system comprises a control and command unit 7 (shown schematically in FIG. 6), which is connected to the hydraulic embossing devices 1 and 2 and the thermal embossing device 6 and has the function of issuing commands and controlling said devices separately. The control and command unit 7 is thus, in the operating position, connected to the mechanical and electronic components of these devices in such a way as to create only one electrical axis.

Thus, according to the method of the invention, the aforementioned hydrotouching and heat embossing processing steps are preferably carried out under the control and at the commands of the control unit and commands for performing said treatments on the intended sections of the nonwoven fabric in accordance with a predetermined model. In other words, the block will contain a memory storing the working model for the nonwoven fabric, according to which the program loaded into the control and command block will issue instructions using electric control signals and commands for performing hydraulic embossing processing at predetermined sections other than the sections, intended for processing by thermal embossing, which has already been completed or will be completed. In practice, the second treatment will be guided in such a way that it is performed on the free areas of the nonwoven material, that is, those areas that are not covered by the first treatment. As a result, both treatments are not performed at the same point, that is, they are not superimposed.

In addition, the process comprises processing said non-woven material, both single-layer and multi-layer, using the technology of hydrotreating so that it covers its surface in the range from 5 to 95% of the entire surface. The rest of the surface, that is, 95-5%, is treated using thermal embossing technology in such a way as to cover 2-30% of the surface. In other words, the surface of the nonwoven material that is not covered by the hydraulic embossing treatment is in turn treated with thermal embossing in the above percentage (2-30%). Preferably, the total surface of the non-woven fabric treated with hot stamping is approximately 50% of the total surface of the non-woven fabric, with the remaining 50% being treated with approximately 10% of thermal stamping. In the case of printing, a portion of 5 to 95% may have a coverage of 2-100%.

In addition, the control unit and commands can also be connected to all electric motors of the drive elements 3, 4, M, which are all located along the production line. The drive elements will not be described here because they are completely conventional and typically contain bases for non-woven material, usually in the form of tapes driven by rotating rolls or rotating drums, as well as rotating elements located at the input and output of each processing equipment.

In particular, the control and command unit is capable of detecting electrical signals emanating from said elements, converting said signals into numerical values representing their angular velocity and torque, comparing said numerical values with ratios of predetermined numerical values for said angular velocity and said torques, and send signals to these elements to correct any possible changes in the specified values that go beyond the specified relationship.

In fact, it is known that if the nonwoven material is a soft, stretchable material, it is easily crushed, mainly during the passage of the hot stamping station, dryer and calender for thermal stamping. In these circumstances, the fibers that make up it are elongated or stretched in the longitudinal direction with respect to the length of the nonwoven material, and as a result of the reaction, they are reduced in the direction of the width of the nonwoven material. Between one point and the next point, non-woven fabric, on the contrary, tends to return to a relaxed state or even to form wrinkles, responding exactly to the release of tension to which its fibers were subjected, thus causing changes in thickness and weight and deteriorating mechanical properties (longitudinal strength / transverse direction and elongation).

The formation of folds prevents the achievement of a substantially flat surface on which appropriate processing can be performed.

Therefore, the control system and commands described above, allows you to eliminate these disadvantages and get the "area" of non-woven material intended for the second processing in the proper position.

In other words, the control unit receives electrical signals, which are converted into parameters indicating, for example, the angular velocity of the rotating elements and the moment (torque). To this end, the angular velocities of the elements are then compared with each other and compared with pre-set values that are set for each different element and non-woven product, as a function of its characteristics (weight, durability, elongation). In particular, the specified target values are calculated in such a way as to establish their relationship, determined according to the physical characteristics of the nonwoven material, that is, according to the typology of the nonwoven material, as shown in the introductory section of the present description. Accordingly, the drive system of all rotating elements must be coordinated so that the supply of non-woven material within the equipment does not cause the above-mentioned wrinkling effects. Thus, the control and command unit sends electrical signals to the aforementioned electric motors to correct any possible changes in the set angular velocity when they go beyond the limits of certain relations. In other words, the control and command unit constantly controls the individual angular velocities of the rotating elements, recording any changes that may occur due to any variability in the physical characteristics of the non-woven fabric, that is, for example, any changes in thickness, weight and humidity. These changes can cause elongation of the fibers of the nonwoven fabric between one point and the next. Consequently, the processing may vary as a result. Therefore, the control and command unit acts on the angular velocity of the rotating elements only to balance any possible elongation effects. This regulation is very important, mainly taking into account the fact that the processes of hydrotouching and thermal stamping are carried out continuously and in accordance with the production of non-woven material (with high speeds, even above 400 m / min).

FIG. 2 schematically shows a production line substantially similar to the production line described with reference to FIG. 1, whereby the same reference numbers indicate identical items or equipment.

Additional control, which can be carried out according to the method corresponding to the invention, is carried out electronically (using automatic closed-loop control) with a continuous correction system for the moment of the pair and the angular velocity of the moving elements. In particular, a closed loop is obtained by using a system with a color video camera as a converter, which keeps the fixed “markers” made during the processings under control and intervenes in the event of relations / distances other than those set and saved. In other words, closed-loop control comprises at least one image pickup device TV1, TV2, shown schematically in FIG. 2, which is connected to the control and command unit in operating position and is suitable for continuous monitoring of a nonwoven sheet to detect the presence of any folds or changes in the watermarking or thermal stamping processing model relative to a given standard.

The image capturing device TV1 may be, for example, a camera or a video camera. Particularly preferred is a color digital video camera that is capable of capturing part of a non-woven material, for example, emerging from equipment. The image captured by the video camera is sent to the control unit and commands in the form of electrical signals, which are converted by the specified unit into digital data. This digital data is compared with standard data stored in the memory of the control unit and commands and representing, for example, a character or pattern that must be reproduced on a nonwoven material in a specific position. The corresponding program, loaded into the specified control unit and commands, will perform the comparison operation of the above data, and if any differences are detected, it will send electrical signals to various processing or drive elements in order to change, for example, their angular velocity to correct the error. Alternatively, or at the same time, the presence of wrinkles on the nonwoven fabric can be detected by the indicated video camera and corrected completely similarly to that described above.

In addition, the system may comprise a plurality of sensors S1, S2, S3, S4 located along the production line and having the function of detecting the presence of a stretching effect at certain points on the nonwoven sheet. A stretching effect is a condition in which a sheet of nonwoven material is kept stretched, that is stretched, without causing the fiber to elongate, so as to prevent wrinkling, while the nonwoven material is processed and transported, as well as any compression thereof.

The tensile sensors S1, S2, S3, S4 are, as such, known devices that send signals to the control unit and commands the tension of the nonwoven fabric, and this unit will in turn act on the drive elements to correct changes in the effect of stretching (or tension ) in the same manner as described above, that is, by adjusting their angular velocity and / or torque.

Alignment control is another control that can be included in the method. This control consists in keeping the signs and / or patterns aligned with the width of the nonwoven fabric using the central sensor C and the side sensors L. The side sensors L (shown in FIG. 3B) are located along the edges E of the bases M for the nonwoven fabric, while the central sensor C is located either above or below the bases and in the middle with respect to the width of the nonwoven material. The sensors allow you to constantly measure the distance between the median line in the longitudinal direction separating the nonwoven material and the side edges in such a way as to detect any change and send signals to the control unit, as a result of which the web position correction system may interfere with the process. The correction system is implemented by devices (not shown) that are known in the art and, therefore, they will not be described below.

According to a first embodiment of the invention, a method for manufacturing a nonwoven material, such as described above, may include a printing step comprising:

- preparing printing equipment 8 for non-woven material W, containing a driven base 9 for holding said non-woven material, and at least one driven printing element 10;

- filing the specified equipment specified sheet of non-woven material;

- printing on the specified non-woven material under control and by the commands of the above control unit 7 and commands,

in which the specified control unit and commands in the working position are connected to the specified base and at least one printing element so that it detects electrical signals coming from the specified base and at least one printing element, converts these signals into numerical values representing the state of their angular velocity and torque compares the indicated numerical values with the ratios of the given numerical values of the indicated angular velocities and the indicated rotating ENTOV and sends signals to said base and at least one printing element to correct any possible variations of said values which fall outside said ratios. Both the printing equipment and the corresponding printing method preferably correspond to those described in the international patent application PCT / IT2004 / 000127 of the present applicant, which is incorporated herein by reference.

Preferably, the method comprises a step in which the control of electric motors that drive the rotating elements of the equipment is separately carried out electronically by the control unit and commands, so that the same electrical axis is mentioned.

In particular, said control for obtaining one electric axis mentioned for all electric motors of rotating elements refers to what has been described above with respect to controls and commands for hot stamping and thermal stamping.

Even more preferably, the control performed by the control unit and the commands can be carried out thanks to additional automatic closed-loop control by the image capturing apparatus TV3 (FIG. 3), described in detail above, and essentially having the same function as described in international patent application PCT / IT2004 / 000127.

Preferably, the method may also include an operation step of using holding means 11 to hold a sheet of nonwoven material on the outer surface of the base, as described in said international patent application.

The operation step of applying the holding means can be carried out using suction fans described in detail in the indicated international patent application, which by suction of air from the outside of the base 9 or the press roll (shown in FIGS. 3-5) through through holes (not shown) made in its circumference, the non-woven material is held in the desired position in order to ensure correct printing performance (coefficient of use of the area of the mold-bearing surface for different dyes / forms).

Preferably, the method according to the invention also comprises the step of controlling the actuator motor for the suction fans using said control unit and commands so that the suction force can be changed according to the typology of the non-woven material held and moved by the pressure roller 9. Indeed, for example, if the non-woven Since the material is multilayer, it will be necessary to increase the suction force with respect to the single-layer nonwoven material.

In addition, the method may include the step of separating water from the air that the suction fans suck in. Said separation step is preferably carried out using separators (not shown), such as those described in the aforementioned patent application.

The printing step is carried out using methods of flexographic printing (ink) or screen printing (color paste), which are common and, therefore, will not be described here in any additional details. However, it should be noted that the method and equipment corresponding to the invention allow printing of signs and / or patterns / figures in many colors, since engraved rolls are located around the pressure roll 9. Preferably, printing may be carried out with 2-12 inks, and therefore, the method may include the step of controlling the selection of inks.

In addition, the method comprises treating said non-woven material using water embossing technology so as to cover its surface in the range of 5 to 95% of the entire surface. The remaining surface, that is, from 95 to 5%, is treated using thermal stamping technology so as to cover the surface in the range from 2 to 30%. In addition, a surface not covered by two treatments can be printed with a coverage of 2-100% of the surface.

Another object of the present invention is to provide an installation for the manufacture of non-woven materials (obtained by spunlace technology, obtained by spunbond technology, mechanically stitched, stitched and coated) directly on the processing line in the manner described above.

Figure 3 shows the installation, consisting of a set of equipment located along one production line containing at least one equipment 1, 2 for hot stamping and one equipment 6 for thermal stamping for processing non-woven material W and the control unit 7 and commands (Fig .6), which in the working position is connected to the mechanical and electronic components of each of these devices for hot stamping and thermal stamping so that the corresponding treatments are carried out on the intended parts of the non-woven fabric material.

In particular, the control and command unit 7 corresponds to that described above with reference to the processing process, as a result of which it will not be described here further.

In addition, as described above, the control and command unit 7 can be connected to all electric motors of the drive elements 4, M, which are located along the production line using electric lines, as shown in Fig.6.

In addition, the installation may contain a system of video cameras TV1, TV2 as converters, as described above, to obtain additional means of controlling the production process using an automatic correction system with a continuous and closed loop.

The installation may further be provided with a plurality of sensors S1-S4, which are located along the production line to detect the constant presence of the aforementioned tensile effect.

Preferably, the installation can also be equipped with alignment control devices comprising said central C and side L sensors, as described above.

According to an embodiment of the invention, the apparatus may comprise equipment 8 for printing on a nonwoven fabric in the manner described in international patent application PCT / IT2004 / 000127.

In particular, this equipment corresponds to well-known printing machines, to which innovative adaptations were applied to obtain high-quality and high-speed printing. These adaptations consist of specific modifications made to flexographic machines, which are essentially known in the art, such as the F80 flexographic machine supplied by FOCUS / FUTURA or the 906 FAST 2 flexographic machine model 160/3500 supplied by FLEXOTECNICA or the like cars. Preferably, auxiliary machines such as F70 unwinder, F90A winder, F401 loader, F11A pipe machine, F30A cutting machine, F12 pipe unwinder F12, supplied by FOCUS / FUTURA can be connected to machines of this type.

In general, modifications are essentially represented by:

- individual motorization of each rotating element, i.e. input / output rolls of the conveyor for the product, pressure roll and engraved rolls;

- the use of a control unit and commands to ensure the joint submission of commands and control the angular velocities of these rotating elements;

- the possible use of a closed loop control system with a video camera;

- a possible modification of the pressure roll so as to provide it with suction openings;

- the possible location of the suction fans inside the pressure roll flush with the indicated holes and with the space between the various engraved rolls;

- the possible supply of hot air between the individual printing rollers for drying the ink;

- the possible use of pumps with water separators if printing on wet non-woven material is required;

- the possible use of input rolls with the function of mechanical expanders.

Printing equipment for non-woven material usually contains a pressure roll 9, also called a back-up roll, at least one engraved roll 10 or a printing element, means 11 for holding the non-woven sheet on the base, a water separator (not shown), a control and command unit 7 and a guide means 12 suitable for guiding and holding a sheet of nonwoven material when moving to and from said equipment (only incoming is shown in FIG. 3).

In particular, the pinch roll is represented by a conventional roll, in which, however, through holes (not shown) are drilled around its entire circumference. These through holes allow communication between the outer surface of the circle and the interior of the pinch roll.

In addition, at least one engraved roll 10 is located inside said pinch roll. Preferably, said at least one engraved roll consists of a plurality of rotating engraved rolls having the function of printing characters, dyes and / or patterns on a material supported by a pressure roll. In particular, each engraved roll can be driven by an independent electric motor.

Driven holding means 11 are arranged inside the pressure roll and in the space between two rotating engraved rolls, preferably in the form of suction fans having the function of drawing in hot air forcibly guided along the outer circumference of the pressure roll, these means being conventional paint drying equipment. Suction fans can be, for example, simple, completely ordinary fans driven by an electric motor, also completely ordinary, for sucking air from the outside of the pressure roll into its interior through the through holes. Alternatively, said suction fans are pumps such as a vacuum pump or compressor.

The function of the suction fans and through holes made around the circumference of the pressure roll is to firmly hold the base of the nonwoven material on the pressure roll to ensure that, on the one hand, the base does not move when fed along the print line and, on the other hand, is created countering the formation of these folds.

Preferably, said suction fans are connected to a completely conventional water separator (not shown) in the case of wet non-woven printing media. Indeed, in this case, the intake air is saturated with moisture, and in order not to release such moisture into the environment or directly to any of the mechanical parts, the equipment can be equipped with one or more water separators connected to each suction fan. In particular, the water separators can be, for example, conventional condensers in which the fluid is first compressed by a compressor and then expanded in the channel (coil), cooling. The air sucked in by the suction fans 4 is directed to the colder surface of the coil in such a way that contact with the colder surface causes the release of water contained in it in the form of condensate. Alternatively, the separation of water occurs simply due to the mechanical and physical action (centrifugal force and the difference in specific gravity) in a conventional spiral distiller operating on the principle of a steel coil.

The guide means 12 are made in the form of driven rolls. In particular, said guide means are individually and independently driven by an electric motor.

The roll 12 may be located near the pinch roll at the inlet of the nonwoven fabric T to the printing points. These means are mechanical expanding means, that is, they allow an increase in the height of the product and exclude the formation of folds on the basis of non-woven material in the longitudinal direction relative to its length. In other words, the non-woven material, when it is stretched in the longitudinal direction with respect to its length, undergoes a reduction in its height (width). Thus, this expanding means performs the function of restoring the original height of the base of the nonwoven material.

The rolls can be located in front of the equipment, that is, at the end of the printing process for proper management (tension control) of the nonwoven fabric to the next machine, if any, whether it is a dryer (in the case of wet printing) or a winding machine (in the case of dry printing).

Preferably, the equipment is connected to the aforementioned control and command unit 7, shown in FIG. 6, having an independent control and command function for moving all the rotating elements, as well as for suction fans and a possibly used pump.

In particular, the control and command unit 7 is directly connected to all mechanical and / or electronic components of the equipment directly in the operating position so as to create a single electrical axis for all components. The specified control unit and commands are really located in such a way as to detect electrical signals emanating from all rotating elements, converting these signals into numerical values representing the state of their angular velocity and torque, comparing the indicated numerical values with the ratios of the given numerical values for the specified angular velocity and said torques and sending signals to said rotating elements to correct for any possible changes to said values, that go beyond the specified relationship.

In particular, the control unit and commands are directly and independently connected to the electric motor of the pinch roll, each electric motor of the engraved rolls, each electric motor of the guide rollers, as well as to the electric motors of the suction fans and the electric motor of a possible water separator. Then, the electrical signals are converted into parameters indicating, for example, the angular velocity of the rotating elements and the moment (torque). To this end, the angular velocities of the elements are then compared with each other and correlated with pre-set values that are set for each different element and product as a function of its inherent characteristics (weight, resistance, elongation). In particular, the specified target values are calculated in such a way as to establish their relationship, determined according to the physical characteristics of the nonwoven material or, in other words, according to the typology of the nonwoven material, as shown in the introductory section of the present description. Accordingly, the drive system and all rotating elements must be coordinated so that the supply of nonwoven material within the equipment does not cause the aforementioned warping effects. Thus, the control and command unit 7 sends electrical signals to the aforementioned electric motors to correct for any possible changes to the specified angular velocity setpoints when they go beyond certain relationships. In other words, the control and command unit 7 constantly monitors the individual angular velocities of the rotating elements, recording any changes that may occur as a result of any variability in the physical characteristics of the sheet of nonwoven material, that is, for example, any changes in thickness, weight or humidity. These changes can cause elongation of the fibers of the nonwoven fabric between one printing point and the next. Therefore, the print can be changed. Therefore, the control and command unit 7 acts on the angular velocities of the rotating elements directly to balance any possible stretching effects. For example, if the cross-section of the base of the nonwoven material entering the first printing device is thicker than the previous part already subjected to the first printing process, then its passage through the pressure roll and the first engraved roll will be slower and the fibers will be compressed and stretched relative to the previous parts. The resulting print, therefore, cannot be correctly synchronized with the previous one. At this point, the angular velocity of the pinch roll, the engraved rolls that follow the indicated part, as well as all other rotating elements will need to be balanced again to maintain the above specified ratio. This regulation is very important, mainly taking into account the fact that the printing process is carried out continuously and in accordance with the production of non-woven material (up to high speeds exceeding 300 m / min).

In addition, it should be noted that the control and command unit 7 also receives electrical signals from the suction fans and the water separator. Thus, the transport of nonwoven material through various printing points, i.e. engraved rolls, can be precisely adjusted by firmly holding the base of the nonwoven material on the base, which is a pressure roll. In addition, the suction and any possible condensation of water can be precisely adjusted according to the typology of the nonwoven, thereby constantly maintaining optimal printing conditions.

Additionally, the control unit and commands can also control the use of paints imposed by engraved rolls by controlling flow, pressure and viscosity.

From what has been described above, it should be understood that equipment for printing on non-woven material allows, on the one hand, to keep the base of the material well fixed on the pressure roller using a suction system and, on the other hand, to avoid any unwanted elongation of the fibers due to the location of the block controls and commands on individual electric motors of rotating elements to obtain one electric axis and partly also thanks to the specified suction system.

Additional control is carried out electronically (using automatic closed-loop control), the same as described above, with a continuous correction system for the torque and angular speed of the print rolls. In particular, the closed loop is obtained through the use of the image capturing device TV3 as a converter that constantly monitors the fixed “markers” made during the printing process and intervenes in the process when the ratios / distances differ from those set and stored in the memory.

The image pickup apparatus TV3 may be, for example, a camera or a video camera. Particularly preferred is a color digital video camera capable of capturing a portion of non-woven material, for example, leaving a printing point. The image captured by the video camera is sent to the control and command unit 7 in the form of electrical signals and is converted by the indicated unit into digital data. These digital data are compared with standard data stored in the memory of the control unit 7 and commands, and represent, for example, a character or pattern that must be reproduced on non-woven material. The corresponding program, downloaded to the specified control unit and commands, will perform the comparison operation of the above data, and in the event that any differences are detected, it will send electrical signals to various printing elements in order to change, for example, their angular velocity to correct the error. Alternatively, or at the same time, the presence of wrinkles on the nonwoven fabric can be detected by said video camera and completely corrected as described above.

In addition, the printing equipment may include a tension sensor S5 located at a point corresponding to the end of the printing process and before the winding roller 13, as shown in FIG. 3. The specified sensor corresponds to the tensile sensors described above, and interacts with them to regulate the effect of stretching or tension.

The non-woven material that can be subjected to the printing process of the invention preferably consists of fibers listed in the introductory part of this description, either individually or as part of a mixture of products, or as part of three-layer products with pulp or “pulped pulp” between the layers, or in two layers of dissolved pulp fibers.

In particular, if the nonwoven material is formed in accordance with spanlace technology, it has a weight characteristic of between 30 and 250 g / m ² and a fiber length of between 1 and 70 mm (short mono and bicomponent fibers) and contains loose cellulose with a length of <2 , 5 mm following the mechanical “lumen”.

Alternatively, if it is formed in accordance with the spanlace-spanbond technology, it has weight characteristics between 10 and 100 g / m ² and continuous fibers for both a single-layer and a three-layer product (two spun and connected with dissolved pulp between them )

At this stage, the thus obtained nonwoven fabric in the form of a single web can be directly subjected to the printing process according to the invention, or it can be first further processed to obtain a composite material.

Typically, non-woven composite materials are multilayer structures containing two outer layers obtained using spunlace or spunbond technology, and a layer of cellulose or a cellulose-derived material subsequently hydraulically bound between them.

The production of composite nonwoven material typically involves the deposition of the first layer of nonwoven material on an appropriate base, the deposition of pulp on the specified first layer, the deposition of the second layer of nonwoven material, consolidation by the method of hydraulic weaving and final drying. Preferably, after deposition of the first layer of nonwoven material, a pre-weave step can be carried out hydraulically, followed by drying.

Based on the above, the method and equipment corresponding to the invention, allows to obtain a non-woven material with particularly preferred properties of softness and / or resistance, as well as attractive aesthetic characteristics. In addition, the final product can be decorated with multi-color printing, which is performed with extremely high accuracy and surprisingly high productivity.

Non-woven material can in fact be produced with heights of up to 6000 mm, preferably heights between 30 and 6000 mm, more preferably in the range of 100 and 6000 mm (preferred heights are 1650 or 3300 mm).

Continuous printing speeds can exceed 400 m / min and up to about 700 m / min, preferably from 20 to 300 m / min.

Non-woven material can be printed (1-12 colors) only on a small, percentage, surface area (2-3%) and up to the desired coverage of its surface, depending on the use of the non-woven material itself, i.e. for personal hygiene, home cleaning, as doormats, non-woven material for clothes, tablecloths, handkerchiefs, curtains (bedding), bags, containers for products.

The characteristics just described allow operation under absolutely favorable production conditions with respect to the prior art technologies and equipment, and it can be carried out directly on the production line for spinning except, obviously, a suitable autonomous machine.

In addition, the above adjustments by the control unit and commands eliminate the problems associated with the formation of folds, as well as with the danger of tearing the base of the nonwoven material, despite maintaining a high printing speed.

Obviously, specialists in the art in order to meet possible and specific requirements can perform a number of modifications and changes of both equipment and the method for printing on non-woven material, however, they are all considered to be included in the scope of the invention defined by the following claims.

For example, a machine dynamics control program may be stored in suitable electronic instruction sets that can be controlled along the electric axis, electronic paint selection control, and a closed loop video camera.

In accordance with another aspect of the invention, a method of manufacturing a nonwoven material is obtained on which signs and / or patterns are printed and which has a certain softness or durability.

The method comprises a step of processing a nonwoven web by means of water embossing (FIG. 4) or heat stamping (FIG. 5) and a subsequent printing step, the printing step comprising:

- the use of equipment for printing on non-woven material containing a driven base for supplying the specified non-woven material and at least one driven printing element;

- filing the specified equipment specified sheet of non-woven material;

- printing (1-12 colors) on the specified non-woven material under control and at the commands of the control unit and commands described above, and the specified control unit and commands in the working position are connected to the specified base and at least one printing element in this way in order to detect electrical signals from the specified base and at least one printing element, convert these signals into numerical values representing the state of their angular velocity and torque, compare the indicated numerical values with the ratios of the predetermined numerical values of the indicated angular velocities and the indicated torques, and send signals to the indicated base and at least one printing element to correct any possible changes in the indicated quantities that are beyond the specified relations.

Preferably, the control and command unit operates separately and independently on each electric motor, which drives the corresponding rotating element of the equipment in such a way as to correspond with one electric axis.

In addition, the control unit can control that the printing operation is carried out on designated areas other than those on which the hydrotreating or thermal embossing processing has been performed. In other words, as described above, with reference to the fact that the hot stamping and thermal stamping treatments are not superimposed, the printing control is also carried out in such a way that it is performed in areas that are not covered by the specified treatments in such a way that overlapping is eliminated.

The control unit and commands can also be carried out by an additional automatic closed loop, as described above, containing an image capture device.

The method may also include an operation step of using a holding means, such as described above, to hold a sheet of nonwoven material on the outer surface of the base. The working step of using the holding means is carried out using suction fans, which, sucking air from the outside into the base through the through holes, hold the non-woven material on the specified base.

The method also comprises the step of controlling the operation of the holding means by said control unit and commands, as described above.

In addition, the step of separating water from the air sucked in by the suction fans can be applied.

The printing step (1-12 colors) is carried out by flexographic (ink) or screen printing (color paste) printing methods known in the art, and preferably comprises a step for controlling the use of inks by the control unit and commands by optimizing the characteristics of each ink, such as flow rate, pressure and viscosity, depending on the type of non-woven material on which to print. In addition, this step will be carried out exactly as described above.

An expansion step may also be carried out to ensure that the height of the article is maintained constant.

The stages of hot stamping and thermal stamping correspond to the steps described above, and they will not be repeated here.

According to another aspect of the invention, an apparatus for manufacturing a printed nonwoven fabric is obtained, comprising printing equipment 8 and at least one hot stamping equipment 1, 2 (FIG. 4), or thermal stamping equipment 6 (FIG. 5). The corresponding equipment corresponds to that which has already been described in detail above, and may include these controls.

The non-woven material will contain, for example, 5-95% of the entire surface treated by hot stamping, and the remaining surface, that is, 95-5%, printed on 2-100%. In the case where thermal embossing and printing processing is used, the nonwoven fabric may contain 2-30% of the surface treated with hydrotreating, and the rest can be printed.

Claims (33)

1. A method of manufacturing a non-woven material from a single-layer or multilayer sheet of non-woven material by processing the specified sheet at the stages of hot stamping and heat stamping, wherein the indicated embossing steps are applied in any order, characterized in that the two different embossing steps are carried out on the specified non-woven sheet on different designated areas. 2. The method according to claim 1, characterized in that the stages of water stamping and thermal stamping are carried out under control and at the commands of the control unit and commands in such a way that these steps are carried out on different and intended sections of non-woven material in accordance with a given model. 3. The method according to claim 2, characterized in that the predetermined model is read by the program loaded into the control unit and commands in such a way as to give instructions using electrical signals to issue commands and to control that the hydrotouching step is performed on predetermined sections of the nonwoven material other than those covered by the thermal embossing step. 4. The method according to claim 1, characterized in that the step of hydrotouching is carried out so as to cover the surface of the sheet of non-woven material corresponding to 5-95% of the entire surface, and the remainder is treated with thermal stamping. 5. The method according to claim 2, which contains steps
the use of at least one equipment for processing hot stamping and one equipment for processing thermal stamping;
feeding into said equipment a sheet of nonwoven material;
performing hydrotouching and thermal embossing in any order under the control of the control unit and commands, while the control unit and commands in the working position are connected to the specified equipment in such a way as to give instructions using electrical signals to issue commands and control that the hydrotouching and thermal stamping processing are performed on predetermined and intended areas of the nonwoven fabric sheet. 6. The method according to claim 5, in which, during hydrotreating and thermal embossing, the control unit and commands detects electrical signals coming from drive elements for a nonwoven material, converts these signals into numerical values representing the state of their angular velocity and torque, compares these numerical values with predetermined ratios of numerical values of the indicated angular velocities and torques, and sends signals to these elements to correct any possible changes Nij these values, which go beyond these relations. 7. The method according to claim 1, in which the stages of the processing of hot stamping and thermal stamping are performed continuously on the same production line with feed speeds that can exceed even 400 m / min. 8. The method according to claim 2, which comprises the step of automatic closed loop control. 9. The method of claim 8, in which the closed-loop control comprises a system with a color video camera as a converter, which keeps under control the fixed markers made during the process of hot stamping and thermal stamping, and intervenes in the process when the ratios / distances differ from installed and saved. 10. The method of claim 8, in which the closed-loop control comprises at least one image pickup device that is connected to the control unit and commands in the working position and is suitable for continuous monitoring of the nonwoven sheet for wrinkles or changes in the hydraulic embossing model or thermal embossing. 11. The method according to claim 1, which contains the first stage of the processing of hot stamping and the second stage of the processing of thermal stamping. 12. The method according to claim 11, in which the first step of hydrotouching includes first processing a sheet of nonwoven material when moving on a cylindrical base, and a second hydrotreating treatment when moving on a flat base. 13. The method according to claim 11, in which, after the hydrotreatment processing step and before the thermally embossed processing step, the nonwoven sheet is subjected to a drying operation. 14. The method according to claim 1, which contains the first stage of the thermal embossing treatment and the second stage of the hot embossing processing. 15. The method according to claim 1, which comprises the step of winding the nonwoven material onto the bobbin after two stages of hydrotouching and heat embossing. 16. The method according to claim 1, in which the stages of hot stamping and thermal stamping are performed on a sheet of non-woven material so that the corresponding effects of softness and hairiness are superimposed. 17. The method according to claim 1, which contains the step of regulating the stretching. 18. The method according to claim 1, which comprises the step of controlling alignment. 19. The method according to claim 2, which comprises the step of printing after said processing steps by hot stamping and thermal stamping. 20. The method according to claim 19, wherein said printing step comprises
the use of printing equipment for non-woven material containing a driven base for supplying the specified non-woven material and at least one driven printing element;
supplying said sheet of nonwoven material to said equipment;
printing on said non-woven material under control and at the commands of the aforementioned control unit and commands, the specified control unit and commands in the working position being connected to the specified base and at least one printing element in such a way that it detects electrical signals coming from the specified base and at least one printing element, converts these signals into numerical values representing the state of their angular velocity and torque, compares the specified s numerical values with ratios given numerical values of said angular speeds and said torques and sending signals to said base and at least one printing element to correct any possible variations of said values which fall outside said ratios. 21. Installation for the manufacture of non-woven material, which contains a production line containing at least one equipment (1, 2) for hot stamping and at least one equipment (6) for thermal stamping for processing non-woven material (W), a drive element system (3 , 4, M) for supplying non-woven material according to the specified system and the control and command unit (7), in the working position, connected to the mechanical and electronic components of each of the specified equipment for water stamping and thermal stamping so that tvetstvuyuschie processing carried out on dedicated portions of the nonwoven material. 22. Installation according to claim 21, in which the control and command unit (7) is connected to all electric motors of the drive elements (3, 4, M), which are located along the production line, using electric lines. 23. The installation according to item 21, which contains a system of video cameras TVI, TV2 as a converter for obtaining additional means of controlling the production process using an automatic correction system with a continuous and closed loop. 24. The installation according to item 21, which contains many sensors (S1-S4), which are located along the production line to detect the constant presence of a tensile effect. 25. The installation according to item 21, which contains a device for regulating the alignment of non-woven material throughout the production line. 26. The apparatus of claim 25, wherein said devices comprise sensors (L, C) suitable for measuring the position of the nonwoven fabric (W) relative to the drive elements (3, 4, M), and devices suitable for correcting the position of the fabric. 27. Installation according to item 21, which contains equipment (8) for printing, located in conjunction with the production line. 28. Installation according to any one of paragraphs.21 or 27, which contains equipment (8) for printing on non-woven material, containing a base (9), at least one printing element (10), means (11) for holding the non-woven fabric (W ) on the base and guide means (12), suitable for guiding and holding the nonwoven fabric when moving to and from the specified equipment, the equipment being connected to the control and command unit (7). 29. Non-woven material that has areas treated with hot stamping, and areas treated with hot stamping, while these areas treated with hot stamping and these areas treated with hot stamping are different intended areas. 30. The non-woven material according to clause 29, in which the area treated with hot stamping, occupies 5-95% of the entire surface of the non-woven material, and the remainder is treated with thermal embossing. 31. The non-woven material according to clause 29, in which areas treated with hot stamping overlap areas treated with thermal embossing. 32. The use of non-woven material according to any one of paragraphs.29-31 as a wet towel for hygienic purposes. 33. The use of non-woven material according to any one of paragraphs.29-31 as a cleaning cloth that can be impregnated with detergent or wax for furniture.

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