Composite tape for fabric compacting machine and related compacting machine

Abstract

Tape for a fabric compacting machine (1), including: an internal base fabric (6) for compaction felts (4); a first layer (7) of felt fixed on a first side of said internal base fabric (6) by a process of needling of felt fibers through a thickness of said internal base fabric (6); a second elastically deformable layer (8) composed of silicone or rubber fixed on a second side of said internal base fabric (6) opposite to said first side, wherein said first layer (7) and said second layer (8) have respective thicknesses determined such that a neutral plane of a bending stress along the thickness of the tape lies within the thickness of said internal base fabric (6).

Description

[0001] COMPOSITE TAPE FOR FABRIC COMPACTING MACHINE AND RELATED COMPACTING MACHINE

[0002] TECHNICAL FIELD

[0003] This invention generally relates to the production of textile products. More specifically, it relates to a composite tape for a fabric compacting machine and a corresponding fabric compacting machine.

[0004] BACKGROUND

[0005] When a fabric or finished garment is washed or subjected to high humidity, it can easily deform and / or shrink. Indeed, the yams are not inherently dimensionally stable, as they are made of fibers that, like natural fibers, are deformable both longitudinally and transversally. Water and soap act as lubricants between the yarns, which, regaining partial relative mobility, tend to relax and shorten, returning to their original length. This results in the fabric shrinking until the fibers reach dimensional equilibrium, which causes significant problems both during the various stages of fabric processing and in the finished garments.

[0006] In the textile finishing industry, it is common to subject a fabric to a compacting treatment. This treatment primarily serves to stabilize the fabric's dimensions, preventing subsequent shrinkage and / or unexpected dimensional variations, as well as imparting qualitative characteristics such as a specific softness or a desired surface appearance.

[0007] A controlled shrinkage method by compaction is known, called the "Sanfor method," named after its inventor. The Sanfor method guarantees excellent results in terms of dimensional stability of fabrics, particularly knitted fabrics, with a maximum shrinkage of 1% in the warp and weft directions after washing.

[0008] In a system that uses the Sanfor method, a fabric passes through humidification device using steam or water to lubricate the fibers and promote their mobility within the fabric. Generally, the fabric is humidified to reach a water content of approximately 15% by weight. The fabric is then expanded to a pre-established size using a special expanding device and then reaches an area of the system containing an endless conveyor belt driven by a motorized roller and supported by a plurality of feed rollers.

[0009] As illustrated in the diagram in Figure 1 of a part of a fabric compacting machine T, the rubber conveyor belt 1 is squeezed between one of the feed rollers 2 and the motorized heating cylinder 3 and stretches proportionally to the applied pressure. The previously moistened fabric T is fed into the compression zone AB by the rubber conveyor belt 1 and is arranged so that the warp threads are aligned in the direction of feed.

[0010] To understand how the compaction of the fabric occurs, refer to figure 2, which schematically illustrates the operating principle of a compacting machine with rubber belt 1. Indicating with "r" the radius of a feed roller 2 and with R the radius of a motorized heating cylinder 3 of the compacting machine, it can be noted that the rubber belt 1 has a thickness E, when it moves freely around the feed roller 2, and is compressed to a thickness “e” at point F between the feed roller 2 and the heating cylinder 3. By inserting the fabric T to be compacted at point A between the rubber belt 1 and the heating cylinder 3, the fabric T undergoes a slowdown in passing from point A to point F because the speed of the fabric T at point A is given by:

[0011] VA = w * (r+E) and the speed at point F is given by:

[0012] VF = w * (r+e) where w is the angular speed of the feed roller, so:

[0013] VF < VA.

[0014] Once out of the compression zone AB, the rubber tape 1 regains its original thickness, dragging by friction the fabric in contact with it. The warp yarns shorten in the forward direction, bringing the weft yarns closer together. After compaction, fabric T enters a dryer (not shown) where the fibers are completely dried and thus locked in their "shrunk" state.

[0015] A limitation of systems using the Sanfor compaction method is that the achievable level of compaction depends substantially on the thickness of rubber tape 1, generally between 67 and 70 mm, and the deformability of the material from which it is made. Another limitation is the need to keep the rubber tape at a temperature lower than the softening temperature (approximately 65°C) using a water cooling system, resulting in water consumption.

[0016] An advantage of compacting machines using a rubber belt 1 is that they impart a glossy effect and a silky feel to fabric T.

[0017] Figure 3 show's a part of a compacting machine with a felt belt 4, which typically has a thickness of 16 mm to 22 mm. Feit belts 4 for compacting machines are generally made using polyamide, polyester, and aramid fibers needle-punched onto a base fabric. The endless conveyor belt rotates around feed rollers 2, and as shown by the segments transverse to the longitudinal direction of feed of fabric T, the surface of the felt belt 4 that presses fabric T against the surface of the heating cylinder 3 shortens as it. passes from feed roller 2 to heating cylinder 3 due to the reversal of curvature. Consequently, the fabric T in contact with the felt belt 4 shortens correspondingly. Optionally, in felt belt compacting machines 4, the fabric T to be compacted is not in direct contact with the heating cylinder 3, but is placed on a Teflon film 5, as shown in figure 3.

[0018] An advantage over the use of rubber tape 1, shown in Figure 1, is that felt tape 4 resists high temperatures without stretching and, compared to rubber tape 1, is less susceptible to chemical agents that may still be present on the fabric T being compacted. Furthermore, by applying less pressure to the fabric, it creates less crushing of the same.

[0019] SUMMARY

[0020] Tests conducted by the Applicant have shown that it is possible to combine the advantages of compacting with a felt tape with those of compacting with a rubber belt. This excellent result was achieved, at least in part, with a tape for a fabric compacting machine comprising: an internal base fabric for compaction felts; a first layer of felt fixed on a first side of said internal base fabric by a process of needling of fel t fibers through a thickness of said internal base fabri c; a second elastically deformable layer composed of silicone or rubber fixed on a second side of said internal base fabric opposite to said first, side.

[0021] The two layers have respective thicknesses determined such that a neutral plane of a bending stress along the thickness of the tape lies within the thickness of said internal base fabric.

[0022] According to one aspect, the tape has an overall thickness between 18mm and 24mm. According to one aspect, the second elastically deformable layer of silicone or rubber is hot deposited over the internal base fabric.

[0023] The tape of the present disclosure may be used to realize an endless conveyor belt for a. fabric compacting machine, wherein the first layer of felt is arranged in the machine so as to be in contact with the advancement rollers, whilst the second layer of the belt is arranged so as to face against the at least one heated motorized cylinder and be pressed against it.

[0024] The invention is more precisely defined in the claims.

[0025] BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 shows a partial view of a rubber belt compacting machine, at the point where a fabric to be compacted contacts a motorized heating cylinder.

[0027] Figure 2 is a geometric description of the deformations undergone by the rubber belt illustrated in Figure 1.

[0028] Figure 3 is similar to Figure 1 and shows a felt belt compacting machine.

[0029] Figures 4 and 5 show a composite tape of the present disclosure having an internal base fabric for compacting filters, a felt layer, and an elastically deformable silicone or rubber layer, attached to opposite sides of the internal base fabric.

[0030] Figure 6 is a detailed view of the tape profile of Figures 4 and 5, illustrating the composite tape structure for a compacting machine according to the present disclosure.

[0031] Figure 7 shows a partial view of a compacting machine with an endless conveyor bell made of the composite tape of Figures 4 and 5.

[0032] DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0033] The compacting machine belt of the present disclosure will be descri bed with reference to Figures 4 to 7, which show a purely illustrative embodiment of the invention.

[0034] The tape has a composite structure and an internal base fabric 6, for example made of polyester, for conventional compaction felts. A first felt layer 7 is attached to only one side of this base fabric 6 by means of a fiber needle-punching process performed through the thickness of the base fabric 6. A second elastically deformable layer 8, composed of silicone or rubber, for example made of ethylene-propylene-diene monomer (EPDM), is attached to the other, opposite side of the internal base fabric 6.

[0035] According to one aspect, the composite tape of this disclosure has an overall thickness of between 18 mm and 24 mm, so it can be used in current compacting machines that work with felt belts 4, such as the one in Figure 3. This represents a significant advantage since it is currently not possible to use rubber belts 1 in compacting machines designed to work with entirely felt belts 4. In fact, in this latter type of machine, the endless conveyor belts are subject to greater curvatures, so it is necessary to use conveyor belts with a relatively small thickness. The typical thicknesses of rubber belts 1 must instead be relatively large to ensure that they have the necessary mechanical resistance, so with compacting machines using felt conveyor belts 4 it is not possible to obtain compacted fabrics T with a shiny and silky surface effect, which is instead typical of compacting machines using rubber belts 1.

[0036] In the composite tape according to the present disclosure, the first felt layer 7 and the internal base fabric 6 are able to withstand the stresses generated in the compacting machine without being subject to permanent deformations. The elastically deformable second layer 8, being firmly anchored to the internal base fabric 6, is relatively less subject to such stresses and may therefore be much thinner than the thickness typically found in rubber belts 1. Furthermore, the stresses caused by the expansion of the second silicone or rubber layer 8, which heats against the motorized heating cylinder 3, are counteracted by the internal base fabric 6 to which the second layer 8 is firmly attached.

[0037] In one aspect, the second silicone or rubber layer 8 can be hot-deposited directly over the internal base fabric 6, as this securely bonds to it. Alternatively, the second silicone or rubber layer 8 can be glued to the internal base fabric 6.

[0038] A special feature of the composite belt according to the present disclosure is that it is possible to ensure that the second elastically deformable layer 8 does not deform at the plane of connection with the internal base fabric 6. The thicknesses of the first felt layer 7 and the second elastically deformable layer 8 are determined in such a way that, when the composite tape is subjected to bending to rotate around the feed rollers 2, the neutral plane of the bending stress acting along the thickness of the composite belt lies within the thickness of the internal base fabric 6. In this way, the internal base fabric 6 is not subject to tensile / compressive forces due to bending, so that the surface along which the second elastically deformable layer 8 is attached to the internal base fabric 6 is not subject to forces that could cause it to detach. For example, if the first felt layer 7 of the composite tape is of the type of the known felt tapes 4, the second elastically deformable layer 8 will conveniently have a thickness of between 8 mm and 10 mm.

[0039] Figure 7 shows how the tape of the present disclosure can be used in a compacting machine, in which the elements corresponding to those shown in Figures 1 to 3 are designated by the same references.

[0040] The composite tape of this disclosure is used to create an endless conveyor belt wound on the feed rollers of the compacting machine. The first felt layer 7 of the endless conveyor belt faces the feed rollers 2, while the second elastically deformable layer 8 made of silicone or rubber faces the motorized heating cylinder 3, Furthermore, the second elastically deformable layer 8 is pressed against the motorized heating cylinder 3 exactly as occurs in the compacting machines of Figures 1 and 2 that use a rubber belt 1. It is therefore understood that with an endless conveyor belt made using the belt of the present disclosure, illustrated in Figures 4 to 6, a felt belt compacting machine 4 can be used to obtain fabrics that have the same surface finish as machines with rubber belts 1 , but without all the technical drawbacks that rubber belts 1 inevitably entail.

[0041] In one aspect, the second elastically deformable layer 8 of silicone or rubber has a hardness of between 30 and 42 Shore A. Tests carried out by the Applicant have shown that, with a hardness of between this range, the second elastically deformable layer 8 compresses, creating a difference in peripheral speed and a contraction of the fabric that is equivalent to compaction. Typically, the second layer 8 is subject to a maximum longitudinal elongation of between 5% and 25%, when the conveyor belt rotates around a feed roller 2, and to a maximum longitudinal shortening of between 10% and 12%, when the conveyor belt rotates around a motorized heating cylinder 3.

Claims

CLAIMS1. A tape for fabric compacting machine (T), including: an internal base fabric (6) for compaction felts (4), a first layer (7) of felt fixed on a first side of said internal base fabric (6) by a process of needling of felt fibers through a thickness of said internal base fabric (6); a second elastically deformable layer (8) composed of silicone or rubber fixed on a second side of said internal base fabric (6) opposite to said first side; wherein said first layer (7) and said second layer (8) have respective thicknesses determined such that a neutral plane of a bending stress along the thickness of the tape lies within the thickness of said internal base fabric (6).

2. The tape according to claim 1, wherein said tape has an overall thickness between 18mm and 24mm.

3. The tape according to one of the previous claims, wherein said second layer (8) of silicone or rubber has a thickness between 8mm and 10mm,4. The tape according to one of the previous claims, wherein said layer of silicone or rubber is hot deposited over the internal base fabric (6).

5. The tape according to one of the previous claims, wherein said internal base fabric (6) is made of polyester.

6. The tape according to one of the previous claims, wherein said second layer (8) of silicone or rubber has a hardness between 30-42 Shore A.

7. The tape according to one of the previous claims, wherein said second layer (8) is made of Ethylene-Propylene-Diene Monomer (EPDM).

8. The tape according to one of the previous claims, wherein said first layer (7) of felt is made by needling polyamide and / or polyester and / or aramid fibres.

9. A fabric compacting machine, comprising at least advancement rollers (2) configured to rotate so as to advance a fabric (T) to be treated, at least one heated motorized cylinder (3) configured to heat the fabric (T) as it advances and an endless conveyor belt configured to move along a circuit defined by said advancement rollers (2), wherein said heated motorized cylinder (3) is configured to squeeze said endless conveyor belt against at least one advancement roller (2) of said advancement rollers (2), characterized in that said endless conveyor belt is made with the tape according to one of the previous claimswith the first layer (7) of felt arranged so as to be in contact with the advancement rollers (2), whilst the second layer (8) of the belt is arranged so as to face against the at least one heated motorized cylinder (3) and be pressed against said heated motorized cylinder (3).

Images