EP4017927A1

EP4017927A1 - Thermally softenable strip and method for covering elongated articles, in particular lines

Info

Publication number: EP4017927A1
Application number: EP20761194.8A
Authority: EP
Inventors: Kerstin KLINGEBERG; Heike Simonis; Lars Guldbrandsen
Original assignee: Tesa SE
Current assignee: Tesa SE
Priority date: 2019-08-23
Filing date: 2020-08-20
Publication date: 2022-06-29
Also published as: US20220282126A1; WO2021037688A1; CN114341292B; CN114341292A

Abstract

The invention relates to a strip for covering elongated articles, comprising a carrier in the form of a strip, characterized in that at least one side of the carrier in the form of a strip is provided with a plastic material that thermally softens at a temperature of preferably 100°C to 135°C and that comprises a thermoplastic material.

Description

Thermally softenable tape and method for sheathing elongated material, in particular cables

The invention relates to a tape and a method for sheathing elongated material, in particular cable harnesses.

For some time now, adhesive tapes have been used in the industry for the manufacture of cable harnesses. The adhesive tapes are used to bundle a large number of electrical cables before installation or when they are already installed, for example to reduce the space required by the bundle of cables by bandaging and to achieve additional protective functions such as protection against mechanical and / or thermal stress. Common forms of adhesive tapes include film or textile backings, which are usually coated on one side with pressure-sensitive adhesives. Adhesive tapes for wrapping elongated goods are for example from EP 1848 006 A2, DE 102013 213 726 A1, and EP 2497 805 A1.

Current tape wrapped harnesses tend to be flexible. However, this is often undesirable for manufacturing reasons. In production, the cable harnesses are usually prefabricated into a cable plan and then inserted into the object to be equipped, such as automobiles. A cable kit plan corresponds to the actual spatial arrangement of the individual cable looms in the cable set, i.e. which cable strand is bent at which point at which angle, where the positions of branches or bindings are and which connectors the ends of the cable looms are occupied.

In order to keep the individual strands of the cable set in a certain shape so that they can be around the engine compartment, for example Motor can be led around without coming into contact with the motor, injection molded parts are usually attached afterwards around the cable harness wrapped with adhesive tape. However, these injection molded parts have the disadvantage that additional material and assembly costs are incurred.

WO 2015/004190 A1 discloses a method for sheathing elongated material such as, in particular, lines or cable sets, in which the elongated material is wrapped in a helical or axial direction with an adhesive tape with a curable adhesive applied to it, and the one applied to the adhesive tape Adhesive mass is cured by supplying radiant energy such as heat. A temperature of 175 ° C is used for thermal curing.

The disadvantage of this method is the high curing temperature, which is not very practical when assembling cable harnesses during the manufacturing process, for example in the automotive industry. Therefore, adhesive tapes are desirable that can be activated at a maximum of 170 ° C, preferably a maximum of 135 ° C or can be processed at an elevated temperature and are rigid after cooling so that the wrapping of adhesive tapes can be integrated into the production process of the cable harnesses or cable plans. Furthermore, adhesive tapes are preferred which do not have to be activated on the elongated product, but rather in a pre-stored step so that the cable harness does not come into contact with the activation heat. After curing, the adhesive tapes must meet the required dimensional stability requirements. On the other hand, the adhesive tapes must not be activated or hardened during storage, since otherwise they can no longer be used. Finally, the curing should take place within the cycle time of the manufacturing process (approx. 6 min).

In the standard procedure, when processing thermally curable cable wrapping tapes to produce a cable, the cable harness is first wrapped with the cable wrapping tape before the cable wrapping tape is activated. The disadvantage of this procedure is that not only the cable strand itself, but also all attached components, such as temperature-sensitive plug connections, are subjected to thermal energy. Furthermore, the cable insulation of the cable harness can be affected if high temperatures and long dwell times are necessary to activate the cable wrapping tape, because the temperature resistance of cable insulation is often only between 100 and 125 ° C.

An adhesive tape is therefore advantageous which is activated with thermal energy before contact with the cable harness and is then used to encase the cable harness so that the cable harness does not experience any direct thermal energy. This ensures that the cable insulation and other temperature-sensitive components are intact.

The object of the present invention is therefore to provide a tape for sheathing elongated material which meets the requirements described above. The object of the present invention is also to provide a method for sheathing elongated material using the rigid tape according to the invention and a product obtainable with the method.

To solve the technical problems, a tape for sheathing elongated material is proposed, comprising a tape-shaped carrier, characterized in that the tape-shaped carrier is covered on at least one side with a plastic that can be thermally softened at a temperature of preferably 100 ° C to 135 ° C fabric is provided, which comprises a thermoplastic.

According to one embodiment of the invention, the elongated material is a cable harness which comprises a bundle of several cables, such as 3 to 1000 cables, preferably 10 to 500 cables, in particular between 50 and 300 cables. All known thermoplastic plastics and their copolymers such as polyesters, polyols fine, polyamides, polyacetals, polymers from the group of styrene, high-performance thermoplastics such as polyether ketones, polyamide imide, polysulfone can be used as the softenable plastic.

The selection of the softenable plastic depends on the desired operating temperature, activation temperature and temperature stability during storage, transport and long-term use temperature.

Since temperatures of up to 100 ° C can often occur on transport routes, plastics with a softening or melting temperature of> 100 ° C, in particular> 120 ° C, are preferred. The group of polyolefins offers a good combination of softening or melting temperature and rigidity. The group of polyolefins includes polymers that are made from alkenes. The most important representatives include polyethylene (PE) and polypropylene (PP). Polyolefins also include polymethylpentene (PMP), polyisobutylene (PIB) and polybutene (PB). Due to the large number of polymers and copolymers available on the market, the mechanical and physical properties can be precisely adapted to the requirements by using these polymers and copolymers or their mixture and modification thereof.

The use of polyethylene has proven advantageous. Polyethylenes of high density (HDPE / PE-HD) can be mentioned particularly advantageously. HDPE types with a melting range of 130-145 ° C. and a modulus of elasticity in the range of 800-1500 MPa, preferably 900-1200 MPa, have proven advantageous.

Polypropylene should also be mentioned as advantageous. In particular, the copolymers of polypropylene with ethylene as a comonomer fill the requirement with their mechanical and physical properties. A melting or softening range of 130- 145 ° C. and a modulus of elasticity of 800-1500 MPa, preferably 900-1300 MPa, prove to be particularly suitable.

The thickness of the applied layer of soft plastic is advantageously between 50 mpi and 1000 mpi, more preferably between 100 mpi and 750 mpi, particularly advantageously between 150 mpi and 350 mpi.

All known foils and textile carriers such as knitted fabrics, scrims, tapes, braids, needle-punched textiles, felts, woven fabrics (including linen, twill and satin weave), knitted fabrics (including warp-knitted fabrics and knitted fabrics) or non-woven fabrics can be used as carriers, whereby the term at least textile fabrics according to EN 29092 (1988) as well as stitchbonded nonwovens and similar systems are to be understood. A tape in which a woven, non-woven or knitted fabric is used as the carrier is particularly advantageous. Such carriers are described, for example, in WO 2015/004190 A1, to which reference is made here in full.

Furthermore, spacer fabrics and knitted fabrics with lamination can be used. Such spacer fabrics are disclosed in EP 0 071 212 B1. Spacer fabrics are mat-shaped layered bodies with a top layer made of a fiber or filament fleece, a backing layer and individual or tufts of retaining fibers between these layers, which are distributed over the surface of the layered body and are needled through the particle layer and the top layer and the Connect the underlayer to each other.

Particularly consolidated staple fiber nonwovens, but also filament, meltblown and spunbond nonwovens, which usually need to be additionally consolidated, are suitable as nonwovens. Mechanical, thermal and chemical consolidation are known as possible consolidation methods for nonwovens. Nonwovens have proven to be particularly advantageous which are consolidated in particular by sewing over them with separate threads or by intermeshing. Such solidified nonwovens are, for example, on sewing machines of the "Malimo" type from Karl Mayer, formerly Malimo, and can be obtained from Hoftex Group AG, among others.

A fleece of the Kunit or Multiknit type can also be used as the carrier. A Kunit fleece is characterized in that it emerges from the processing of a longitudinally oriented fiber fleece to form a sheet that has meshes on one side and mesh webs or pile fiber folds on the other, but neither threads nor prefabricated sheets be seated. Such a nonwoven has also been produced for a long time, for example on stitchbonding machines of the "Malimo" type from Karl Mayer.

A multiknit fleece is distinguished from the Kunit fleece in that the fleece is solidified by piercing with needles on both sides, both on the top and on the underside. The starting product for a Multiknit is usually one or two single-sided meshed pile fiber nonwoven fabrics produced using the Kunit process. In the end product, both nonwoven tops are formed into a closed surface through fiber meshing and connected to one another by almost vertical fibers. Additional pierceable planar structures and / or spreadable media can also be introduced.

Finally, sewn nonwovens are also suitable as a preliminary product to form a carrier according to the invention and a tape according to the invention. A stitched fleece is formed from a fleece material with a large number of seams running parallel to one another. These seams are created by sewing in or stitching continuous textile threads. For this type of web, stitchbonding machines of the "Malimo" type from Karl Mayer are known.

Needle fleeces are also particularly suitable. In the case of needle-punched nonwovens, a pile of fibers is made into a flat structure with the help of needles provided with barbs. By alternately piercing and pulling out the needles, the material is solidified on a needle bar, with the individual fibers intertwined to form a solid surface. A staple fiber fleece that is pre-consolidated by mechanical processing in the first step or that is a wet fleece that was laid hydrodynamically, with between 2% by weight and 50% by weight of the fibers of the fleece being melt fibers, in particular between 5% by weight, is also particularly advantageous % And 40% by weight of the fibers of the fleece. Such a fleece is characterized in that the fibers are laid wet or, for example, a staple fiber fleece is preconsolidated through the formation of meshes from fibers of the fleece by needling, sewing, air and / or water jet processing. In a second step, the heat setting takes place, whereby the strength of the fleece is increased even more by melting or melting the melt fibers.

Advantageously, and at least in some areas, the carrier has a surface that is ground smooth on one or both sides, preferably a surface that is ground smooth over the entire surface. The smoothly ground surface may be chintzed, as is explained, for example, in EP 1 448 744 A1. In this way, the repellability of dirt is improved.

The starting materials for the carrier are in particular (chemical) fibers (staple fiber or continuous filament) made of synthetic polymers, also called synthetic fibers, made of polyester such as polyethylene terephthalate, polyamide, polyimide, aramid, polyolefin, polyacrylonitrile or glass, (chemical) fibers natural polymers such as cellulosic fibers (viscose, modal, lyocell, copper, acetate, triacetate, cellulon), such as rubber fibers, such as vegetable protein fibers and / or such as animal protein fibers and / or natural fibers made from cotton, sisal, flax, silk, hemp , Linen, coconut or wool provided. However, the present invention is not restricted to the materials mentioned, but rather a large number of other fibers can be used to produce the fleece, which is evident to the person skilled in the art without having to be inventive. Furthermore, yarns made from the specified raw materials are also suitable. In the case of woven or non-woven fabrics, individual threads can be made from a mixed yarn, i.e. they can have synthetic and natural components. As a rule, however, the warp threads and the weft threads are each made of one type.

Polyester is preferably used as the material for the carrier, due to its excellent resistance to aging and the excellent media resistance to chemicals and operating media such as oil, gasoline, antifreeze, and the like. In addition, polyesters have the advantage that they lead to a very abrasion-resistant and temperature-resistant carrier, which is of particular importance for the special purpose of bundling cables in automobiles and, for example, in the engine compartment.

The weight per unit area of the textile carrier is advantageously between 30 g / m ² and 300 g / m ² , more advantageously between 50 g / m ² and 200 g / m ² , particularly advantageously between 50 g / m ² and 150 g / m ² , very particularly advantageously between 70 g / m ² and 130 g / m ² .

According to a particularly advantageous embodiment of the inven tion, a fabric or a fleece made of polyester is used as the carrier, which has a weight per unit area between 50 g / m ² and 150 g / m ² .

The finished coated material is preferably cut to a width of 20 ± 2 mm (any other width is also conceivable) and wrapped in a spiral with an overlap of 50% around the shaped cable bundle. To soften the plastic, a temperature of 130 ° C to 150 ° C for about 10 seconds to 4 minutes is necessary. The temperature can be applied using a hot air dryer, IR radiator, oven, heating jacket, or the like.

According to a preferred embodiment of the invention, the softenable plastic is more than 10%, preferably more than 25%, more preferably after being applied to the carrier sunk into the carrier by more than 50%. A numerical value of, for example, 25% means that the softenable plastic has penetrated over a layer thickness of 25% of the thickness of the textile carrier, i.e. with a carrier with a thickness of 100 mpi over a layer thickness of 25 mpi within the carrier, and although starting from the surface of the carrier on which the softenable plastic is coated, and in a direction perpendicular to the plane spanned by the longitudinal or transverse direction.

The present invention also relates to a method for sheathing elongated material such as, in particular, lines or cable harnesses, a coated tape according to one of the preceding claims being softened by the supply of heat at a temperature preferably between 110 ° C and 150 ° C is then guided in a helical line around the elongated good or the elongated good is enveloped in the axial direction by the tape, the elongated good together with the enveloping tape is brought into the desired arrangement, especially in the cable set plan, the elongated good is kept in the water arrangement until the tape has solidified again by cooling.

According to one embodiment of the invention, the thermal energy is supplied over a period of 10 seconds to 2 minutes, which is compatible with the cycle times of the manufacturing process, so that the elongated product is completely cured after about 6 minutes as soon as it is in the target object such as Automobiles, water vehicles or airplanes.

According to a further embodiment of the invention, the thermal energy is supplied to the belt and held until the belt is guided around the elongated material and / or until it encases the elongated material.

The tape is preferably wrapped around the elongated material in a spiral shape with an overlap of 30% to 70%, more preferably 40 to 50%, in particular about 50%. In FIG. 2, a section in the transverse direction (cross section) shows the tape which consists of a non-woven carrier 31 to which a layer of a thermally softenable plastic 32 which comprises a thermoplastic is applied on one side.

25% of the plastic has sunk into the carrier (33), which results in optimal anchoring.

Also encompassed by the inventive concept is a sheathed elongated good, such as, in particular, a cable set, sheathed with a tape according to the invention, and a vehicle containing such a sheathed elongated good.

Examples:

Example 1 - Manufacture of a coated tape

A 20 mm wide and 100 μm thick PET fabric carrier with a basis weight of 130 g / m ² was deposited with polyethylene HMA 016 from ExxonMobile ™ in a single screw extruder with a temperature profile of 160 ° C. to 220 ° C. and pressed into the fabric carrier in a calender gap . With the help of a roller heated to 20 ° C, the material is cooled to room temperature and then wrapped into a bale.

Example 2 - bending test to determine stiffness

A test sample, consisting of 250 individual cables with a cable cross-section of 0.35 mm ² , was bundled into a sample cable set using 9 mm wide adhesive tape (tesa 51618) so that the sample cable set had a diameter of 23 ± 5 mm and a length of 300 ± 50 mm. The heated stiffening material from Example 1 was wrapped spirally around this sample line set, with an overlap of 50% being ensured. The stiffening material was then allowed to cool to room temperature. The hardened sample lead set was subjected to a bending test to determine the influence of the stiffening material on the stiffness. The bending test was carried out on a tensile testing machine. For this, the sample line set was placed on two jaws with a distance of 70 mm and pressed in in the middle with a pressure fin by a distance of 30 mm and loaded. The force required to deform the measuring path was recorded in Newtons by a tensile testing machine. The test speed was 100 mm / min, both when loading and when relieving the sample line set. The test was carried out at 3 different points on the wiring harness (beginning, middle and end). The bending force results from the mean value of the three individual measurements and was evaluated in three categories as follows:

Evaluation categories 3-point bending test:

+ well suited for the application (500-750 N)

0 limited suitability for the application (400-500 N and 700-800 N)

- not suitable for the application (<400 and> 800 N)

For comparison, a commercially available adhesive tape, tesa ^® 51036, was subjected to the same experiment. The results are shown in Table 1 below.

Example 3 - C-shape test to determine the stiffness at different temperatures

To determine the stiffness of a bent cable sample, a test procedure was developed (C-cable sample bending test). To produce a C-cable sample (see FIG. 1), a cable line (10) with a line cross-section of 0.35 mm ^{2 is} wrapped 100 times around a holder (1) to form a sample line set. The holder (1) has two opposite, semicircular guides (2, 3) with a diameter of 120 mm, which are spaced apart by a distance (A) of about 210 mm. The coiled cable set is shown in FIG. The number of cable windings is 100. The result is a pattern cable set with a diameter of 15 ± 5 mm and a circumference of 690 mm. The cable bundle (10) is tied together with cable ties (4, 5, 6, 7, 8, 9) with a tensile force of 210 ± 10 N at the apices of the semicircular segments and on two straight sections (legs), so that the Cable bundle (10) after removal from the holder has sufficient rigidity so as not to deform. In order to further improve the rigidity of the cable bundle (10), a support (11) is positioned between the legs of the cable bundle and also fixed with cable ties.

The cable bundle (10) produced in this way is removed from the holder and wrapped with the previously heated adhesive tape to be tested (width 19 mm-20 mm) with a 50% overlap. To do this, start wrapping around a cable tie (e.g. 6 or (7)) of the leg in the direction of the circle segment ((6) -> (4) or (7) -> (5)). When the wrapping reaches the cable tie (4) or (5) at the apex of the semicircle segment, this is removed and the wrapping continues to the next cable tie ((4) -> (8) or (5) -> (9)) of the opposite leg continued. The same is done on the other side, on the other semicircle segment.

The samples prepared in this way are fed to the appropriate stiffening method (cooling to room temperature). With a side cutter, the patterns are cut adjacent to the existing cable ties in order to obtain two "C-shaped" cable patterns (C-cable patterns), each of which also has a non-wrapped section on both sides of the semicircular, wrapped section. The cut is made at a distance of the diameter (120 mm) from the apex of the semicircular segment, projected onto the center of the circle.

With a piece of cable loops are tied to the leg ends of the patterns so that they can be hung up at one end a weight can be attached to the other end. The remaining cable ties are now removed as they can falsify the test result. The distance between the legs is now determined.

One of the two samples is stored at room temperature and the other at 60 ° C.

A 1 kg weight is hung on the respective lower leg of the "C test specimen". After one hour, the deflection of the cable bundle is noted (deflection behavior 1 h at room temperature or 60 ° C.) and the weight is removed Deflection determined again (resetting behavior 1 min at room temperature or 60 ° C.). After one hour, the deflection is then determined again and noted (resetting behavior 1 h at room temperature or 60 ° C.).

The determined values of the C-shape deformation were classified into three categories, well suited for the application, suitable for the application to a limited extent and not suitable for the application. The categories were rated as follows:

Evaluation categories C-shape bending test (room temperature):

+ well suited for the application (<15% deflection)

0 limited suitability for use (> 15-30%)

- not suitable for the application (> 30%)

Evaluation categories C-shape bending test (60 ° C):

+ well suited for the application (<25% deflection)

0 limited suitability for the application (> 25-40%)

- not suitable for the application (> 40%)

Evaluation categories C-shape bending test (recovery behavior at room temperature and 60 ° C):

+ well suited for the application (<10% deflection)

0 limited suitability for use (10-30%)

- not suitable for the application (> 30%) For comparison, a commercially available adhesive tape, tesa ^® 51036, was subjected to the same experiment. The results are also shown in Table 1 below. Table 1:

Legend: + well suited for the application o limited suitability for the application - not suitable for the application

Claims

1. Tape for sheathing elongated material, comprising a tape-shaped carrier, characterized in that the tape-shaped carrier is provided on at least one side with a thermally softenable plastic at a temperature of preferably 100 ° C to 135 ° C, which is a thermoplastic includes.

2. Tape according to claim 1, characterized in that the thermally softenable plastic has a softening or melting temperature of> 100 ° C, particularly preferably> 120 ° C.

3. Tape according to claim 3, characterized in that the thermally softenable plastic is a polyolefin or a mixture of a polyolefin and a further thermoplastic th.

4. Tape according to one of the preceding claims, characterized in that the carrier material comprises a polyester fleece.

5. Tape according to one of the preceding claims, characterized in that more than 10% of the softenable plastic has sunk into the carrier.

6. A method for sheathing elongated material such as special lines or cable harnesses, wherein a coated tape according to one of the preceding claims is softened by the supply of heat at a temperature between 130 ° C and 150 ° C and then in a helical line the elongated good is guided or the elongated good is enveloped in the axial direction by the tape, the elongated good together with the enveloping tape is brought flat in the desired arrangement, in particular in the cable set, the elongated material is held in this Anord voltage until the tape has solidified again by cooling.

7. The method according to claim 6, characterized in that the softenable plastic is softened by the supply of thermal energy at a temperature of 110 ° C to 140 ° C.

8. The method according to claim 6, characterized in that the thermal energy is supplied over a period of 0.5 seconds to 2 minutes.

9. Sheathed elongated good, such as a cable set in particular, received according to at least one of the preceding claims.

10. A vehicle containing encased elongate material according to claim 9.