ITUD970116A1 - WET SANDING PROCEDURE FOR TEXTILE MATERIAL AND RELATED DEVICE - Google Patents

Abstract

Wet grinding method for textile material, applicable to textile material of cotton, wool, synthetic material, elasticised material and similar, used to give to the touch of the fabric particular aesthetic effects such as the ageing effect, the pre-washed effect, the "peach fuzz" effect, the method providing a preliminary step performed upstream of the grinding step wherein the fabric (11) is wet or dumped, the grinding step being performed by causing the fabric (11), maintained under tension between a drawing element at inlet (18) and a drawing element at outlet (24), to pass around a plurality of rotary grinding cylinders (22) distributed on the circumference of a rotary drum (21) and lined with material having abrasive properties. Wet grinding device for textile material, which can be used on textile material of cotton, wool, synthetic material, elasticised material and similar, used to give to the touch of the fabric particular aesthetic effects such as the ageing effect, the pre-washed effect, the "peach fuzz" effect, the device comprising means to wet or damp the advancing fabric (11) arranged upstream of the grinding assembly (19), the grinding assembly (19) comprising a plurality of rotary grinding cylinders (22) distributed on the circumference of a rotary drum (21), the device comprising at least a drawing element at inlet (18) and a drawing element at outlet (24) of the fabric (11), the grinding cylinders (22) being lined with material having abrasive properties.

Description

Description of the invention having as title:

"WET GRINDING PROCESS FOR TEXTILE MATERIAL AND RELATED DEVICE"

FIELD OF APPLICATION

The present invention relates to a wet grinding process for textile material and the relative device as set forth in the respective main claims.

The invention is applied in the finishing treatments of fabrics and knitwear to give the hand of the fabric particular aesthetic effects, for example aging effects, pre-washing effects or the so-called "peach skin" effect.

The invention is substantially applicable to any type of textile material, both in the cotton sector and in that of synthetic fibers, in the wool sector and in the knitwear sector.

More particularly, the invention is particularly suitable in the case of application to knitted fabrics and / or to fabrics that are at least partially elastic or elasticized.

STATE OF THE TECHNIQUE

The grinding treatment, well known in finishing processes, basically consists in dragging the textile material around a plurality of rollers superficially coated with abrasive paper or other material having abrading properties.

The action of said abrading material produces a partial removal of hybrid material, causing the formation of a more or less accentuated surface hair according to the final result or the hand characteristics to be obtained.

In the known art, grinding is normally carried out on dry textile material, by making the fabric pass around coated cylinders and arranged horizontally or vertically. In order to obtain higher quality results, it has recently been proposed to carry out the sanding process on wet or at least humidified fabric before it is sent to the sanding rollers.

For this purpose, the fabric is immersed in an impregnation tank, or subjected to a wetting or spray humidification step, in a position upstream of the grinding zone.

Wet grinding, compared to grinding on dry fabric, has the characteristic of causing a less accentuated and therefore more superficial abrasion action, with less removal of fibrous material and less lifting of the pile, this leading to obtaining a hair short and dense.

The treated product has pronounced characteristics of softness without causing the formation of fluff to the touch.

Wet buffed fabric undergoes less stress and therefore has less loss of consistency and strength.

Wet grinding also allows you to apply to the fabric, during the impregnation phase, particular chemical products, for example softeners, resin-based products or other, to obtain particular and desired results by hand, for example to increase its softness, shine. or to give fuller aspects.

A rinsing area is normally provided downstream of the grinding area followed by a possible drying area.

A wet grinding machine is known in the art in which the textile material is first immersed in an impregnation tank containing liquid, possibly with additives, and then sent to a series of rotating grinding cylinders, normally between 3 and 6 in number, arranged in a fixed position substantially on a single horizontal plane and interspersed with return rollers.

Said grinding cylinders are coated with abrasive material, for example abrasive paper, diamond paper or the like, and exert their grinding action in the short section in which they are in contact with the fabric.

Said machine has a plurality of drawbacks.

First of all, there is a very short contact time between the fabric and the grinding cylinder which, combined with the reduced number of cylinders, forces each of said cylinders to perform a singularly very intense and concentrated action.

The required high intensity of the action of each grinding cylinder determines a more accentuated removal of fibrous material combined with a greater lifting of down, which leads to an aesthetically less appreciable result, as well as to a loss of resistance of the treated textile material.

Another drawback of said known machine derives from the fact that the fabric, in its approach path to the impregnation tank, during immersion in it and along the entire section of cooperation with the grinding cylinders, has long free and unsupported or guided sections. .

In consideration of the fact that the fabric is wet, in the free sections it is subject to marked longitudinal and transverse undulations, which then determine, in the areas of contact with the grinding cylinders, evident and undesired treatment irregularities.

This phenomenon is very accentuated in the case of treatment of knitwear fabrics or elasticized fabrics, this causing the substantial impossibility of using this machine on this type of fabrics if good results are to be obtained both in terms of quality and uniformity.

A further drawback derives from the fact that the fixed position of the grinding cylinders determines no other effect of cooperation with the fabric than that deriving from the rotation of the cylinder itself.

The fixed position of the grinding cylinder also entails problems of effective surface washing of the circumferential area not in contact with the fabric, forcing the use of particular surface configurations of the cylinder itself to obtain effective results.

The size of the cylinders itself must necessarily be large, which leads to construction, maintenance, assembly, transport, installation problems and more.

In order to solve all these drawbacks by adopting an extremely effective, versatile, functional solution, adaptable to any type of fabric and capable of guaranteeing extremely high quality results, the present applicant has studied, tested and implemented the present invention.

EXPOSURE OF THE FOUND

The present invention is expressed and characterized in the respective main claims.

The secondary claims expose variants to the main solution idea.

The purpose of the invention is to provide a wet grinding treatment for textile material suitable for guaranteeing a high quality and uniformity of treatment on substantially any type of textile material, also and particularly in the case of knitwear fabrics, stretch fabrics and fine fabrics and light.

Another purpose is to obtain the formation on the hand of the fabric of an extremely short and dense layer of fluff, characterized by high uniformity and regularity without compromising in any way the resistance of the fabric itself, since the grinding treatment is uniformly distributed over a high number of cylinders. each of which performs a little accentuated and little intense action.

A further object is to obtain an extremely compact, functional, versatile device as it is adaptable to different types of treatment and / or fabric and suitable to be integrated upstream or downstream with auxiliary devices for drying, rinsing, humidity regulation or other. .

According to the invention, the textile material to be sent for grinding is subjected to a wetting or humidification treatment before being sent to the grinding cylinders.

This wetting or humidification treatment can take place, in a first solution, by guided immersion in an impregnation tank located upstream of the grinding zone.

According to a variant, the fabric is previously wet or humidified by means of spray systems, shower systems or the like.

Once this wetting or humidification phase has been carried out, after a possible squeezing phase which serves to regulate the moisture content of the fabric and to eliminate excess water, the fabric is sent to the sanding unit.

According to the invention, the grinding unit consists of a rotating barrel structure on the circumference of which a plurality of rotating cylinders of reduced diameter and coated with abrasive paper or other desired material having abrading characteristics are mounted.

The number of rotating grinding cylinders is variable and can be adapted according to the size of the barrel and the device.

One solution of the invention provides for the use of at least sixteen grinding cylinders, advantageously between twenty-four and thirty-six in number.

According to the invention, the diameter of the grinding cylinders is between 60 and 120 mm.

advantageously around 80 installments.

The solution of using small diameter grinding cylinders, defining a circular path and mounted on a rotating barrel, has many advantages with respect to known solutions.

First of all, the grinding is much more distributed as it is carried out by a large number of cylinders, each of which can exert a little accentuated and not very intense action.

This allows to obtain a high effect of uniformity and softness of the hand of the fabric, without irregularities and without the formation of areas subjected to more or less accentuated intensity treatments.

In addition, the fabric is less punctually stressed so that its strength is less compromised.

Another advantage derives from the fact that the fabric can be correctly accompanied and guided along its entire path starting from the impregnation area and throughout the sanding area, thus preventing the formation of corrugations and irregularities, both longitudinal and transversal, due to the pulling on the wet fabric, called undulations and irregularities, negatively affecting the uniformity of the treatment.

A further advantage is given by the fact that the grinding effect is accentuated by the combined effect of the rotating grinding cylinders and the swing effect of the barrel which is also rotating. According to the invention, a maximum unaccompanied stretch of the fabric is provided, for the whole grinding path, not exceeding three centimeters. The grinding device according to the invention provides means for pulling the fabric arranged in and out of the rotating barrel and equipped with systems for adjusting the pull so as to adapt the pull to the different characteristics of the fabric and to the different working conditions.

According to a variant, said tension adjustment systems comprise load cells.

Upstream and / or downstream of the rotating barrel there are squeezing systems which are used to regulate the humidity of the fabric both entering the grinding unit and leaving it. According to a variant, the squeezing system at the outlet of the grinding unit is associated with a rinsing tank.

The device according to the invention comprises means for cleaning and washing the surface of the grinding cylinders in the area in which they are not in contact with the fabric.

In a first solution, said cleaning and washing means comprise spray elements oriented towards the cylinders and associated with pressurized water supply means.

According to a variant, said cleaning and washing means comprise an impregnation tank in which the grinding cylinders, rotating with the barrel, are immersed at least partially.

According to a variant, the rotating barrel comprises means for making the grinding cylinders rotate even in the phase in which they are not gripping the fabric, thus ensuring maximum effectiveness, on their entire circumference, of the surface cleaning and washing operation.

In one solution, said rotation means comprise at least one belt or chain closed in a loop around the axes of said grinding cylinders and cooperating with the main drive chain which acts on the cylinders only for the portion in which they are gripped on the fabric.

According to a variant, the impregnation tank into which the fabric is immersed is associated with heating means.

According to another variant, the washing and cleaning means of the grinding cylinders are associated with means for heating the washing liquid.

According to a further variant, the device is equipped with an openable lid so as to allow processing even on dry fabric, creating an air circulation by means of a suction tank cooperating with the rotating barrel and through the opening defined by said opening lid. , being the box-like structure containing the rotating barrel connected at the bottom to an electric aspirator.

The rotating barrel, as well as the grinding cylinders, can be equipped with both clockwise and anticlockwise rotation, making all possible combinations.

The grinding cylinders can also, according to a variant, be divided into two groups with alternating pile and counter-pile cylinders, for example even or odd, associated with different and independent movement systems to achieve the desired combinations of movement in the equiverse or in the opposite direction. from one group to another.

However, all desired combinations can be made, for example by rotating two adjacent cylinders in one direction and one in the opposite direction or something else.

ILLUSTRATION OF DRAWINGS

The attached figures are provided by way of non-limiting example and illustrate some preferential solutions of the invention.

In the tables we have that:

- fig. 1 illustrates a first solution of the grinding device according to the invention;

- fig. 2 shows on a reduced scale a variant of fig. 1;

- fig. 3 schematically illustrates the system for moving the grinding cylinders on the rotating drum.

DESCRIPTION OF THE DRAWINGS

The attached figures 1 and 2 illustrate two embodiments of the sanding device 10 for wet fabrics 11 according to the invention.

The fabric 11, guided through a suitable accompanying and guiding system 12 schematically illustrated, is sent to an impregnation tank 13 in which it is immersed for.According to a variant not illustrated, the wetting step takes place by means of a spray system, a shower or other similar system.

In this case, there is a first direction reversal roller 14 which widens the fabric 11 and accompanies it to a return roller 15, from which the fabric 11 is then transferred to a second direction reversal roller 16, completely immersed in the liquid. of the impregnation tank 13 and from here to a second return roller 17.

From the second return roller 17 the fabric 11 is sent to an infeed drive roller 18 which sends it to the actual grinding unit 19. The configuration of the feeding path made by the rollers 15, 16, 17 and 18 is such that the fabric 11, from the first section in which it begins to be wet or humidified and therefore more subject to tension or undulations if subjected to tension, has free sections unaccompanied and guided very small, not exceeding 3 cm, advantageously not exceeding 2 cm.

This ensures that, longitudinally or transversely to the fabric 11, those irregularities or deformations are not created, which then negatively affect the uniformity and continuity of the grinding treatment performed downstream.

In this case, the impregnation tank 13 has heating means 35 for regulating the temperature of the wetting liquid, said temperature being able to vary according to the invention in a range between 15 ° and 98 ° C.

According to a variant, the impregnation tank 13 has means for adding and dosing additives such as softeners, resin-based substances or other so as to achieve particular treatments and effects on the fabric 11.

In the present case, the second return roller 17 cooperates with a squeezing roller 20 to perform a compression action on the fabric 11 entering the grinding unit 19 so as to regulate its degree of humidity to the desired value, eliminating any excess liquid. .

Said squeezing roller 20 can be adjusted at least according to a radial direction to the conjugate second return roller 17 to graduate the humidity level in a range comprised, according to the invention, between 20 and 200%.

The grinding unit 19 comprises a barrel 21 rotating around a central axis 23, on the circumference of which a plurality, in this case twenty-four, of grinding cylinders 22 of reduced diameter, for example of the order of 80 mm, are mounted abrasive, such as sandpaper, diamond paper or the like.

The fabric 11 wraps around said grinding cylinders 22 for a substantial part of the circumference of the rotating barrel 21, defined between the inlet drive roller 18 and an outlet drive roller 24.

Said drawing rollers, inlet 18 and outlet 24, are associated with tension adjustment systems not shown, for example with load cells, to always guarantee the desired and correct tension of the fabric 11 around the grinding cylinders 22.

The combined action of the grinding cylinders 22 determines on the fabric 11 an extremely uniform grinding treatment over a very distributed area, so that the action of the single cylinder 22 can be made less accentuated and intense.

This solution also makes it possible to keep the fabric 11 always accompanied even in the actual grinding phase, thus ensuring a minimum deformation of the fabric subjected to the pulling and a minimum deteriorating action of the fabric resistance.

The fabric 11 coming out of the grinding unit 19 and picked up by the exit drawing roller 24 is sent, in the case of fig. 1, in a rinse tank 25 in which it is accompanied by return and reversal rollers 115, 116 and 117 similar to those seen with reference to the impregnation tank 13.

The rinsing tank 25, in a solution not shown, can be replaced by spray or rinsing shower devices.

It can also cooperate with devices for heating and / or adding desired softening and / or treating substances.

In this case, in cooperation with the rinsing tank 25 there is a unit with fabric washing spouts 34 and a humidity regulation unit comprising a squeezing roller 120 cooperating with the return roller 117.

The humidity of the fabric 11 at the outlet can be adjusted to values in a range between 20 and 200%.

In the variant of fig. 2, the rinsing tank 25 is not present and the fabric 11 is immediately sent to the humidity compression and regulation unit comprising at least one squeezing roller 120, said unit also performing the function of pulling and extracting the fabric 11 from the grinding unit 19 .

Downstream of the humidity control unit there is, in fig. 1, a drying unit 26 of the radiant type.

The fabric 11 is then sent, by means of an evacuation system 27, towards suitable collection and accumulation areas, not illustrated.

In this case, the grinding unit 19 comprises a cleaning and washing system 28 of the surface of the grinding cylinders 22 in the area in which they are not in contact with the fabric 11.

In the case of fig. 1, said cleaning and washing system 28 comprises an oriented or orientable spray system 29 associated with means for feeding the washing liquid which acts on the surface of the grinding cylinders 22.

In the solution of fig. 3, the grinding cylinders 22 cooperate with a movement system which provides a main belt 30 connected to a driving pulley 31 which rotates them in the phase in which they are in engagement with the fabric 11, and a pair of second belts, 32a on the right side and 32b on the left side, closed in a loop which rotate the respective groups of cylinders 22, pile cylinders and counter-pile cylinders, in the section in which they are not in contact with the fabric 11.

The simultaneous rotation of the cylinders 22, even in the non-gripping section, and of the rotating barrel 21 ensures that the jet emitted by the spray system 29 affects the entire circumference of the cylinders 22 themselves during the phase in which they are not gripped. with fabric 11.

This cleaning and washing action is necessary in the treatment of wet fabrics for the removal of fluff and fibers which remain adherent to the surface of the cylinder 22 and which must be removed before said cylinder comes into contact with the fabric 11 to perform a new action. of grinding.

In the variant of fig. 2, cleaning and washing are carried out by partially immersing the cylinders 22 in their non-gripping portion inside an impregnation tank 33.

The rotation speed of the barrel 21, the free rotation speed of the cylinders 22 and the size of the tank 33 can be adjusted so that the transit of said cylinders 22 in correspondence with said tank 33 determines the cleaning of the entire circumferential surface of each cylinder 22 .

The tank 33 can have heating means 135 and / or can cooperate with means for introducing additive and cleaning substances.

The rotating barrel 21 can be provided with both clockwise and counterclockwise rotation at a number of revolutions in a range between 1 and 150 rpm.

The grinding cylinders 22 can also be provided with clockwise or anticlockwise rotation, realizing the desired combinations between the group of pile cylinders and the group of counter-pile cylinders which can rotate equivially or in opposite directions from each other.

The rotation speed of the cylinders is advantageously included in a range between 0 and 1500 rpm.

The rotating barrel 21 is housed, in this case, inside a box-like structure 36 defining a lower suction area 38, also having the function of collecting tank for excess water when working in wet conditions, and closed at the top by an openable lid 37. In this case, the lower intake area 38 is connected to a water drain 41.

The grinding device 10 according to the invention can also be used to treat dry fabrics, eliminating the impregnation or humidification step.

In this case, the path may be the one indicated by dashed lines in figs. 1 and 2 in which the fabric 11 passes directly from the roller 14 to the roller 17 and then to the input drive roller 18.

In dry treatment, the upper cover 37 is brought into the open position 37a (dashed in fig. 2) to allow air exchange, and the lower suction area 38 is connected to a duct 39 connected to an electric aspirator, which is not shown to create air circulation.

The variant of fig. 2 also provides for the use, at the outlet, of a dancer roller 40 to graduate and adjust the output pull of the fabric 11 between the pulling and squeezing unit consisting of the cylinders 24 and 120 and the evacuation unit 27.

Claims (1)

CLAIMS 1 - Wet grinding process for textile material, applicable to textile material in cotton, wool, synthetic material, stretch material and the like, used to give the hand of the fabric particular aesthetic effects such as the aging effect, the effect prewashing and the "peach skin" one, characterized in that it provides a preliminary wetting or humidifying phase of the fabric (11) performed upstream of the grinding phase, said grinding phase being performed by passing the fabric (11), maintained under tension between an inlet towing element (18) and an outlet towing element (24), around a plurality of rotating grinding cylinders (22) distributed on the circumference of a rotating barrel (21) and coated with material having abrasive properties. 2 - Process according to Claim 1, characterized in that in the advancement path from the sending phase to the wetting or humidification phase to the grinding phase, the fabric (11) has unaccompanied or unguided sections not exceeding 3 cm. 3 - Process as claimed in Claim 1 or 2, characterized in that the wetting or humification step is carried out by immersion in an impregnation tank (13). 4 - Process as claimed in Claim 1 or 2, characterized in that the wetting or wetting step is carried out by spraying liquid on the passing fabric (11). 5 - Process as in one or the other of the preceding claims, characterized in that between the wetting and humidification phase and the grinding phase there is a phase for regulating the humidity and / or for eliminating excess water. 6 - Process according to one or the other of the preceding claims, characterized in that the wetting or humidification step is carried out with liquid at a controlled temperature. 7 - Process as claimed in one or the other of the preceding claims, characterized in that it provides for a cleaning and washing step of the grinding cylinders (22) in their section not in contact with the fabric (11). 8 - Process according to Claim 7, characterized in that the cleaning and washing step is carried out by sprays of cleaning liquid directed towards the surface of the grinding cylinders {22}. 9 - Process according to Claim 7, characterized in that the cleaning and washing step is carried out by partial immersion of the grinding cylinders (22) in an impregnation tank (33). 10 - Process as claimed in one or the other of the preceding claims, characterized in that downstream of the grinding step there is a rinsing step. 11 - Process as claimed in one or the other of the preceding claims, characterized in that downstream of the grinding step there is at least one step for regulating the humidity of the fabric (11). 12 - Process according to one or the other of the preceding claims, characterized in that at least one drying phase is provided in cooperation with the step of regulating the humidity of the fabric leaving the grinding step. 13 - Wet grinding device for textile material, usable on textile material in cotton, wool, synthetic material, stretch material and the like, used to give the hand of the fabric particular aesthetic effects such as the aging effect, the effect and the "peach skin" one, characterized in that it comprises means for wetting or humidifying the advancing fabric (11) and arranged upstream of the grinding unit (19), said grinding unit (19) comprising a plurality of rotating grinding cylinders (22) distributed on the circumference of a rotating barrel (21), the device comprising at least one inlet pulling element (18) and one outgoing pulling element (24) of the fabric (11), the grinding cylinders ( 22) being coated with material having abrasive properties. 14 - Device as claimed in Claim 13, characterized in that the grinding unit (19) comprises at least sixteen grinding cylinders (22) distributed on the circumference of the rotating barrel (21). 15 - Device as claimed in Claim 13 or 14, characterized in that the grinding cylinders (22) have a diameter between 60 and 120 mm. 16 - Device as claimed in one or the other of the preceding claims from 13 onwards, characterized in that the wetting or humidifying means comprise an impregnation tank (13) associated with return rollers (15, 17) and / or inversion (16) defining an immersion path of the fabric (11) inside said impregnation tank (13). 17 - Device as claimed in one or the other of the preceding claims from 13 onwards, characterized in that it comprises at least one humidity regulating unit arranged upstream of the grinding unit (19) and comprising at least one squeezing roller (20) with adjustable positioning . 18 - Device as claimed in one or the other of the preceding claims from 13 onwards, characterized in that the impregnation tank (13) has heating means (35). 19 - Device as claimed in one or the other of the preceding claims from 13 onwards, characterized in that it comprises means for adjusting the tension of the fabric (11) associated with the inlet pulling element (18) and / or with the exit one (24). 20 - Device as claimed in Claim 19, characterized in that the tension adjustment means are load cells. 21 - Device as claimed in one or the other of the preceding claims from 13 onwards, characterized in that it comprises a rinsing tank (25) arranged at the outlet from the grinding unit (19). 22 - Device as claimed in Claim 21, characterized in that it comprises a humidity control unit, with at least one squeezing roller (120), arranged downstream of the rinsing tank (25). 23 - Device as claimed in Claim 21 or 22, characterized in that it comprises drying means (26) arranged downstream of the rinsing tank (25). 24 - Device as claimed in Claim 21, characterized in that the rinsing tank comprises a fabric washing unit (34). 25 - Device as claimed in one or other of the preceding claims from 13 onwards, characterized in that it comprises a cleaning and washing system (28) arranged externally to the rotating drum (21) and cooperating with the surface of the grinding cylinders (22) when they are not in contact with the fabric (11). 26 - Device as claimed in Claim 25, characterized in that the cleaning and washing system (28) comprises at least one spray element (29) oriented and / or orientable against the surface of the grinding cylinders (22). 27 - Device as claimed in Claim 25, characterized in that the cleaning and washing system (28) comprises an impregnation tank (33) in which the grinding cylinders (22) partially immerse themselves in their section not in contact with the fabric ( 11). 28 - Device as claimed in one or the other of the preceding claims from 13 onwards, characterized in that it comprises means for rotating the grinding cylinders (22) when they are not in contact with the fabric (11). 29 - Device as claimed in Claim 28, characterized in that said means comprise at least one chain (32a, 32b) closed in a ring on the circumference defined by the axes of the grinding cylinders (22). 30 - Device according to one or the other of the preceding claims from 13 onwards, characterized in that it comprises a box-like structure (36) enclosing the rotating barrel (21) and having a lid (37) at the top and a suction area at the bottom. (38) connected to an electric fan. 31 ". Device as claimed in claim 30, characterized in that the lid (37) has at least one open working position (37a) adopted in the dry grinding steps of the fabric (11). 32 - Grinding process as in one or the other of the preceding claims from 1 to 12, characterized in that it adopts the contents referred to in the description and in the drawings. 33 - Grinding device as claimed in one or the other of the preceding claims 13 to 31, characterized in that it adopts the contents referred to in the description and in the drawings.