DE2339452C3 - Process for coating the outer surface of textile tubes - Google Patents

Description

From GB-PS 9 57 929 a method for coating textile hoses is known in which first the outer surface of the textile tube is coated and then the coated tube is turned. To carry out the first process step, d. H. for coating the textile hose, this British patent describes two different methods. According to one method the textile tube is in a flat state, d. H. as a textile flat hose, through a latex or a Plating bath containing plastisol passed; then it is applied to the outer surface of the Textile hose applied coating vulcanized or gelled. The other method uses the Textile tube a gas-tight air cushion is introduced into which air is pumped to the textile tube to inflate, whereupon you lead the inflated textile tube through the coating bath and so The coating applied to the outer surface of the textile tube vulcanizes or gels However, the methods described are complicated to carry out and have a number of shortcomings afflicted, as will be shown below. They are not suitable for the production of high-quality commercial products, which must have a uniformly thick coating.

In the first-mentioned method, in which a textile flat hose is passed through a coating bath there is a considerable difference in the flow condition between that on the flat broadsides of the textile tube adhering and the coating liquid adhering in the folded edge area, the coating liquid located in the folded edge area

'5 is or will be less than that on the plates Amount of coating liquid adhering to the broad sides. As a result, the solidification or hardening The layer formed by the coating liquid is extremely thin in the region of the folded edges. To This known method can therefore not be a uniformly thick coating on the outer Achieve the surface of the textile tube. Rather, two are formed in the longitudinal direction of the hose running, diametrically opposed strips in which the coating is thinner than on the remaining parts of the hose. These thinly coated areas of the textile tube form slightly fsine holes when the hose is used for further operations or treatments a fire hose, e.g. B. the eversion or the pressure test is subjected. These fine holes mean serious faults in the fire hose. In addition, those on the folding edges of the Textile hose formed, relatively thin areas of the coating extremely easily through external force, e.g. B. friction to damage. This creates the risk that these places are injured during the further work steps in the manufacture of fire hoses. In summary it can thus be stated that the former method does not provide a uniformly thick coating and thus the advantages achieved by coating the outer surface of the textile tube largely restricted.

In contrast, with the second method, in which the coating is applied to the inflated textile tube, no difficulties, to apply a coating of uniform thickness to the outer surface. This is upon it due to the flowing state of the coating liquid adhering to the outer surface is the same at all points on the outside of the textile tube, since it has a circular cross-section is bloated. However, this second known method also has serious disadvantages. On the one hand it requires complicated operations and makes the production of fire hoses economical difficult. When using this method, several additional operations are required, including the introduction of the air cushion in the textile tube, inflating the air cushion and removing the air cushion from the hose required after the formation of the outer coating layer, thereby eliminating the process becomes extraordinarily complicated. On the other hand is the

according to this method by means of the inflated air cushion inflated textile tube stiff and therefore stiff difficult to bend. If the inflated hose is to be bent, make sure that the

The radius of curvature is at least 50 cm. If the inflated tube is forced into a narrower If the radius of curvature is bent, a smooth bend is no longer obtained. The hose bends then with the formation of kinks or angles at several points (cf. FIG. 2). This disadvantage leads obviously too elevated. Cost of the coating device. When the direction of the bloated Hose changed during the coating of the outer surface of the textile hose should be, rollers or rollers must be used for this with a diameter of at least 1 m can be used to ensure a smooth, kink-free curve of the to ensure inflated hose. This increases the size of the loading device considerably In addition, a considerable amount of space is required for the device to run smoothly of the inflated tube during immersion in the feed bath and solidification guarantee. After all, it causes some problems to keep the air cushion inflated by means of overpressure inside it. The required perfect Sealing of the air cushion in the textile tube, which completely prevents air from escaping is technically very difficult to achieve. Even a small amount of air escapes shrinkage of the inflated textile tube and thus ultimately to the formation of an unevenly thick one Coating. Even more disadvantageous is the fact that leakage air through the cavities in the reticulate structure of the textile tube emerges, whereby the on the outside of the textile tube formed coating is torn, resulting in the formation of pinholes or cracks in the dei coating formed when the tube is turned inside out. Thus, this is also a well-known method economically uninteresting and in particular in terms of space requirements, the device and the costs also disadvantageous in that complicated operations are required. For example, already introduces minor technical error, such as the aforementioned leakage of air, ultimately to generation of products with irreparable defects.

The method described in GB-PS 9 57 929 for the production of fire hoses by Coating the outer surface of a textile tube and then turning the adjacent one over Textile hose is basically a useful method, but unfortunately there are several suffers from severe defects in terms of the coating of the outer surface of the textile tube. It there is therefore an urgent need for an improved method of uniform coating the outer surface of textile tubes with a latex or a plastisol.

The invention is based on the object of a method for coating the outer surface of textile hoses available, which makes it possible to open the outside of the textile hoses easy way and without the use of large and space consuming. Performing with a uniformly thick splint made of rubber or a synthetic resin. This task will solved by the invention.

It has now been found that the problem of uneven coating in textile flat hoses can be solved in that one after passing through the coating bath and before Solidification of the applied layer that adheres to the flat broad sides of the textile flat hose Coating liquid removed

The invention thus relates to the subject matter characterized in the claims.

According to the invention, for the removal of those adhering to the flat broad sides of the textile tube Coating liquid uses a squeezing device that is used to only apply to the plates Squeeze off any coating liquid adhering to the broad sides of the textile flat hose. As the use the squeezing device a significant reduction in the on or in the flat sides of the Textile hose adhering coating liquid and at the same time the transport of a certain Amount of coating liquid from the plate broadsides to the area of the folded edges is made possible the resulting coating is thick, especially in the folded edge area. That way become the ordinary Coating process and the special coating process combined with each other with advantage up to a uniform coating of the desired thickness is obtained.

The method of the invention can be used with any textile tubing, e.g. B. with woven fibers, knitted or knitted tubes. Preferred fiber materials are natural and synthetic organic fibers as well as inorganic fibers such as cotton, linen, glass, regenerated cellulose, Polyamides and polyesters.

The coating liquid is generally in the form of a viscous liquid, e.g. B. as a latex, solution or paste of a natural or synthetic rubber or a synthetic resin before and forms a water-insoluble coating on the textile tube when heated. Natural latices or synthetic rubber are particularly preferred. The coating liquid may contain vulcanizing agents, Contain polymerization accelerators and other additives, such as plasticizers or colorants, which are generally used for these purposes. The base polymer is optionally with Chloroprene blended to improve the weatherability and ozone resistance of the coating.

When carrying out the method according to the invention in practice it has been shown that the Coating liquid should preferably have a moderate viscosity. Is the viscosity of the If the coating liquid is too low, it will flow under the action of the squeezing device in the folded edge area Remaining coating liquid back to the flat sides, making it extraordinary It becomes difficult to build up a coating of sufficient thickness in the folded edge area. In particular for To achieve thicker coatings, the use of coating fluids with something is recommended higher viscosity, e.g. B. from about 30 to 500 cP.

If you lead the textile hose out of the bath with the coating liquid without squeezing out the hose, to prevent the coating liquid from sticking mainly in the area of the flat broad sides of the To achieve hose, the viscosity of the liquid is preferably increased by dilution, e.g. B. with Ammonia water, lowered and generally held at about 30 to 150 cP (i.e., relatively low viscosity). However, if you lead the textile hose out of the bath with the coating liquid with subsequent squeezing through the squeezing device to avoid sticking

... J. i

of the coating liquid mainly in the folded edge area of the hose, the viscosity of the coating liquid becomes accordingly increased and generally maintained at a value of about 300 to 55OcP (i.e., relatively high viscosity). Otherwise the coating liquid located in the folded edge area would partially become the flat broadside area of the textile hose flow and in this way the accumulation of the coating liquid prevent practically exclusively in the folded edge area.

The solidification of the coating liquid applied to the outer surface of the textile tube takes place by heating, e.g. B. with a hot gas flow, an electric heater or infrared radiation, wherein solvent contained in the coating liquid evaporates and vulcanization of the resin or the rubber takes place when a vulcanizing agent or a polymerization accelerator is contained in the coating liquid.

The method of the invention is particularly useful for forming uniform coatings on the outside suitable for textile hoses that are used to transport liquids under high pressure. An example of this is making fire hoses by coating the outside of a fire hose Textile hose with a rubber or a synthetic resin and then turning the coated textile hose. In addition, the method of the invention can also be used to advantage Manufacture of coatings on the outside of hoses used to improve their durability will.

The squeezing device for carrying out the method of the invention is preferably around a pair of pinch rods or nip rollers that move over time in the process between the passage through the coating bath and the solidification of the textile tube, in particular immediately before the solidification treatment. While squeezing rods when passing through If you do not turn the coated textile hose, it will turn when using nip rollers or -rolls light To improve the squeezing effect, a pair of squeeze bars or squeeze rollers or -rolls generally arranged vertically so that the externally coated textile tube from the side In this case, each of the two squeeze bars or squeeze rollers or -rolls brought into contact with each flat broad side of the externally coated hose that the two rods or rollers under increased tensile stress pass through. They are under the same conditions Squeeze bars somewhat more effective for removing the coating liquid from the flat sides of the plate than the nip rollers, which rotate as the coated textile tube passes through. Other solutions, e.g. the use of sponges or an "air doctor", are also possible. as long as this does not adversely affect the coating liquid adhering in the folded edge area will.

The invention is described below with reference to the drawings. It shows

Fi g. la is a cross-sectional view of a flat-lying Textile hose (textile flat hose) with an unevenly thick coating on its outside, Fig. Ib is a cross-sectional view of the hose of F i g. 1 a when inflated,

Fig.2 is a side view of a forcibly in one small radius of curvature of bent, inflated textile tube,

3 shows a schematic, partially sectioned illustration of a preferred example of an apparatus for carrying out the method of the invention and
F i g. 4 is a schematic representation of one of a

ίο A pair of pinch bars or rollers which are preferred Squeezing device.

Figs. La, Ib and 2 show the disadvantages of known methods versus the method of the invention. Fig. La shows a cross-sectional view of a Textile flat hose that has been coated by the usual method and on the flat broad sides has more coating liquid than at the folded edges. F i g. Ib gives the unevenly coated Textile flat hose from FIG. 1 a again in the inflated state and clearly shows that the Layer thickness of the coating in the area of the folded edges is less.

F i g. Fig. 2 shows an inflated, forcibly bent in an arc with a small radius of curvature Textile hose and shows that a smooth bend can no longer be achieved.

In the case of the in FIG. 3 reproduced apparatus for performing the method of the invention is a Textile hose 1 as a textile flat hose downwards into a bath 2 filled with a coating liquid 3 guided where the running textile tube under the action of a lower roller 4, which is in the liquid is arranged to rotate, is deflected upwards. The hose 1 led out of the bath is then in an oven 5 where the coating liquid adhering to the outside of the hose solidifies will. The hose is then deflected downwards under the action of an upper roller 6 this process is repeated a few times (in FIG. 3, 8 times), a Coating 7 (see FIG. 4) formed from rubber or a synthetic resin. In practice, the running hose 1 after leading out of the second, fourth and sixth bath so in contact with three pairs of pinch bars or rollers 8 brought that only the flat broad sides of the hose are squeezed together while squeezing out the adhering coating liquid. Here the Main part of the coating liquid squeezed off; however, part of the coating liquid becomes the Folded edges are pressed in this way when the pinch rods or rollers pass through Tube hardly protrudes on the flat broadsides, but a relatively thick coating in the folded edge area. In contrast to this, the Squeeze bars or rollers non-continuous hose a thick coating on the flat sides and only a thin coating in the folded edge area. By appropriate combination of the above

Operations will result in the formation of a coating of uniform thickness on the entire exterior Surface of the textile tube allows

F i g. Fig. 4 shows a preferred arrangement of a pair of pinch bars or rollers 8, which refer to a common, perpendicular axis are arranged. As for squeezing off the coating liquid a certain pressure on the squeeze bars or rollers from the wide sides of the plate

is required, it is preferred to have a pair of nip rolls 8 as shown in FIG. 4 shown to be arranged.
The examples illustrate the invention.

example 1

Using the methods shown in FIG. 3 is a cotton tube 8 times
Subject to operation:

(A) The textile flat hose is passed through a bath with a rubber latex with a solids concentration of 50% and a viscosity of 100 cP and then until the solidification of the adhering coating liquid is heated immediately. This process is repeated 5 times.

(B) The flat hose is passed through a bath with a rubber latex having a solid concentration of 50% and a viscosity of 350 cP. After the on the flat sides of the Coating liquid adhering to the flat hose is squeezed out, the hose is up to Solidification of the coating liquid heated. This process is repeated 3 times.

In this way a rubber coating is obtained with a uniform thickness of about 0.4 mm on the outer surface of the cotton tube. A commercially available rubber latex is used for the coating the following composition is used:

23 39 452 8th ^JetSCh - component Parts by weight Natural rubber (solids) 100 sulfur 1.2 5 zinc oxide 1.5 accelerator 0.8 Titanium dioxide 2.0 orrich antioxidant ■ 2.0 endemic wax 1.5 ίο stabilizer 1.0

Example 2

. In a manner similar to Example 1, a polyester flat hose for fire extinguishing purposes is 6 times in a low viscosity latex of 30 to 150 cP and 4mai dipped in a high viscosity latex of 300 to 50 ocP, then at a speed of 4 m / min peeled off and finally dried at 90 ° C. for 3 minutes. Here you get on the outer Surface of the textile tube has a coating with a uniform thickness of 0.5 mm. In this case owns the latex used has the same solid content as in example 1.

The amount of coating formed on the outside of the polyester textile tube differs is in the area of the flat sides of the folding edge area and is determined by the viscosity of the Latex affects. The influence of the differences in the areas and the viscosity on the thickness of the on the The coating formed on the outside of the hose is shown in the following table:

Viscosity of the latex

Queischsticks

Thickness of the coating
flat broadsides

Folding edge area

30 to 150 cP
300 to 500 cP

absent
available

0.5 mm
0 mm

0.1 mm
0.4 mm

A total of 0.5 mm

0.5 mm

From the preceding examples it can be seen that the use of a squeezing device, e.g. B. a pair of pinch rods, the coating liquid adhering to the flat broad sides of the hose can effectively remove and that by an appropriate combination of the process variant using these squeezing devices with the process variant omitting the Squeezing device the achievement of a coating with a uniform layer thickness on the outer surface of the hose.

For this purpose 2 sheets of drawings

• 30 248/137

Claims (3)

Patent claims: 1. A method for coating the outer surface of textile hoses with a uniformly thick layer of rubber or a synthetic resin by passing a textile flat hose through a coating bath and then solidifying the coating liquid adhering to the hose,
characterized in that one a) a common coating process in which a textile flat hose is inserted into a Coating liquid-filled bath and led to the outside of the bath Outgoing hose adhering coating liquid with omission of a Squeegee is solidified with b) a special coating process using a squeeze device after the textile flat hose has passed through the coating bath and Before the adhering coating liquid solidifies, the one on the broad sides of the plate of the textile flat hose, but not the coating liquid adhering in the area of the folded edges Will get removed, combined. 2. The method according to claim 1, characterized in that the special coating process the removal of the broad sides of the plate using a squeezing device of the textile flat hose adhering coating liquid while maintaining the Coating liquid adhering in the area of the folded edges by means of one or more pairs of Squeeze bars or rollers carried out, which are arranged temporally before the solidification stage. 3. The method according to claim 2, characterized in that one (s) or more pinch rods or rollers used, which are arranged on a substantially perpendicular axis are, and the textile flat hose passes through it in an S-shape.