EP0797497A1

EP0797497A1 - Process and device for varying the thickness of thin-walled vulcanised dipped articles, in particular operating and examination gloves

Info

Publication number: EP0797497A1
Application number: EP95941661A
Authority: EP
Inventors: Winfried Lehmann; Gottfried Schmidt; Wolfgang Goebel
Original assignee: Gummiwerke Rotpunkt GmbH
Current assignee: Gummiwerke Rotpunkt GmbH
Priority date: 1994-12-15
Filing date: 1995-12-04
Publication date: 1997-10-01
Also published as: AU4301796A; DE4444800A1; WO1996018485A1

Abstract

The invention concerns a process and a device for varying the thickness of thin-walled vulcanised dipped articles, in particular operating and examination gloves, in which the dipped articles are made by applying a coagulant-latex-dipping bath-film coating to a dipping form and then vulcanising said coating. According to the invention, an additional coagulant layer is applied to the dipping form by spraying or painting in a desired region of greater wall thickness or as a way of achieving an even wall thickness. For this purpose the additional coagulant layer is applied to the dipping form during or immediately after removal from the dipping bath. The concentration of the additional coagulant layer is equal to or greater than the coagulant concentration in the dipping bath used for forming the foundation film coating.

Description

Method and device for varying the thickness of thin-walled vulcanized diving articles, in particular

Surgical and examination gloves

description

The invention relates to a method and a device for carrying out the method for varying the thickness of thin-walled vulcanized diving articles, in particular surgical and examination gloves, according to the preamble of claim 1.

It is known to manufacture thin-walled vulcanized diving articles, in particular surgical gloves or examination gloves, on discontinuously or continuously operating diving systems.

In such immersion systems, essentially vertically hanging immersion molds located on a chain or belt conveyor are introduced into one or more immersion baths, which are equipped with e.g. B. coagulant and latex are filled. When passing through the immersion pools, the immersion form is wetted to form a surface film. After the immersion molds have been removed from the immersion bath, the surface coating film is used to transfer them to a vulcanizing section. As a result of the vulcanization process, different elastic articles are produced in accordance with the particular dipping form, which are then removed from the dipping forms and finished. With the above-mentioned continuously operating immersion systems, an extraordinarily high productivity can be achieved per se, but there is the problem that especially complicated shaped diving articles, for example surgical and examination gloves, after the essentially vertical dipping of the dipping forms from the immersion pool have a different thickness of the surface film formed.

This is because adhering films or layers are still in the liquid phase and the film formed is thickened by dripping and running back down, so that an uneven wall thickness or too small thickness in the shaft area of the immersion form for the production of surgical or examination gloves Episode is.

In order to achieve a uniform tau film wall thickness over the entire length of the immersion body or the immersion form, it has therefore already been proposed that the exchange curves, ie. H. to design the trajectories or curves when moving the dipping forms out of the plunge pool in such a way that slower, step-by-step removal takes place, so that there are different lengths of dwell time in the respective dipping bath, based on the respective section of the dipping form. This method allows a certain improvement in the homogeneity of the

Layer thickness distribution, however, larger and more complex immersion systems are necessary due to the required exchange curves or movements.

It has also been proposed to add a second immersion step in a separate immersion bath to improve the homogeneity of the wall thickness distribution after a first coagulant immersion process using an appropriate immersion bath. In this case, the entire immersion form to be wetted is immersed in the first immersion bath and is immersed in the second immersion bath with a concentration which may have changed, only up to half or another predetermined value of the first immersion depth. This creates the problem that, particularly in the case of surgical and examination gloves, the hand area can be made more uniform with regard to the wall thickness, but a visible transition in the wall thickness is formed.

Especially with surgical and examination gloves, however, it is necessary that the area of the fingertips is not too thick so as not to unnecessarily restrict the surgeon's sense of touch. On the other hand, however, it is necessary that the shaft area, which is exposed to great loads when the gloves are slipped on, should be correspondingly stable and provided with a higher wall thickness.

It is therefore an object of the invention to provide a method and a device for varying the thickness of thin-walled vulcanized diving articles, in particular surgical and examination gloves, which allow even with complicated and not completely rotationally symmetrical diving forms or diving articles with high Productivity and tailored to the operation of the respective diving system to produce diving articles with uniform or defined different wall thicknesses over the entire diving length or parts thereof.

The object of the invention is achieved with an object according to the features of patent claims 1 and 9, the subclaims comprising at least expedient refinements and developments of the object of the invention.

An essential basic idea of the invention is, based on a diving process known per se, in which diving articles are produced by coating a diving mold with coagulant latex bath and subsequently vulcanizing, an additional coagulant layer by spraying or brushing in a desired area of greater wall thickness or to apply for wall thickness homogenization, this aforementioned additional coagulant layer during removal dipping process or immediately after the completion of the immersion of the dipping form is applied. According to the invention, the concentration of the coagulant for applying the additional coagulant layer is less than, equal to or greater than the respective concentration in the corresponding immersion bath.

According to a further idea of the invention, during the application of the additional coagulant layer by means of spraying or brushing, a relative movement is carried out between the dipping form and a corresponding spraying or coating device, so that the additional coagulant layer or the corresponding coagulant film on the dipping form is the same on all sides or the same extent can train distributed.

According to a further basic principle of the process, if surgical and examination gloves with particularly small wall thicknesses are to be produced in the hand area, the dipping process, ie. H. the time immersion process for applying the base film is shortened and the amount of additional coagulant layer to be applied is increased by spraying or brushing in order to obtain corresponding wall thicknesses in the shaft area of the glove.

As a result, surgical and examination gloves can be produced which, particularly in the area of the fingertips or hands, do not hinder the surgeon and which are therefore accordingly sensitive.

The method according to the invention is particularly advantageous when a continuous immersion system is used, which has chain or belt conveyors, with the aid of which a multitude of immersion molds are continuously introduced into an immersion bath in succession, then removed from the bath and fed to a vulcanizing section . In this case, the dipping forms are arranged essentially vertically, that is to say hanging vertically, and in this essentially vertical position they dip into and out of the dipping baths. In such systems in particular, there are undesirable wall thickness changes due to the flow of the surface film, which can be compensated for by the method according to the invention of spraying or brushing on an additional coagulant layer, in particular in the area of the shaft.

On the device side, according to the basic idea of the invention, a spray device is provided such that an additional coagulant layer can be applied to areas of the immersion form during the immersion process or immediately after the immersion process of the immersion form.

For this purpose, the spray device is arranged at a predetermined distance from the immersion mold or molds, and a specific opening angle of the nozzle of the spray device or a predetermined spray jet is set.

An essential basic idea on the device side is that in order to avoid additional drive means or complex mechanical constructions in continuous immersion systems, the respective immersion forms are rotatable and each have a race on their upper, ie. H. have the shaft end.

The race connected to the immersion mold is in a frictionally operative connection with a fixedly arranged rail essentially parallel to the direction of movement of the belt or chain conveyor, so that when the rotatable immersion molds attached to the chain conveyor are moved along with the help of the race and the fixed rail and the developing frictional force are set in rotary motion.

In one embodiment of the invention, the running rail is designed such that the immersion form is moved or moved out of its perpendicular or vertical position by a predetermined angle, so that the frictional force between The race and rail are increased and the required rotational movement of the immersion form can be achieved with a high degree of certainty.

Of course, in further embodiments, the impeller and the running rail can be friction-increasing means or form-fitting elements, i. H. Have teeth that interlock.

In another embodiment of the invention, the spray device is designed in such a way that offset and / or opposing spray nozzles are directed onto the immersion molds, so that wetting on all sides with an additional coagulant layer can be achieved without the throughput at con ¬ continuous diving systems is affected.

The invention will be explained in more detail below using an exemplary embodiment and with the aid of figures.

Here show:

Fig. 1 shows a schematic representation of a variety of

Immersion molds attached to a chain or belt conveyor of a continuous immersion system;

2 shows a basic illustration of the immersion of immersion forms in a plunge pool;

Figure 3 shows the arrangement of the rail, which is operatively connected to the race of the dip mold.

4 shows the arrangement of a spray device for carrying out the method according to the exemplary embodiment.

1, the basic structure of a diving system according to the exemplary embodiment is to be explained first. A large number of immersion molds 1 are attached to a chain or belt conveyor 2 of a continuously operating immersion system via joints 3 and suspension devices 4. The immersion molds 1 are rotatable relative to the suspension devices 4. At the upper end 5 or in the shaft area of the immersion mold 1, a race 6 is fixed. The race 6 is, for example, provided with a surface rubber coating or surface coating (not shown).

The running direction of the chain or belt conveyor 2 is symbolized by the arrow. The dipping forms 1 have a hand area 7 in addition to the shaft area 5.

As described in the introduction, in the case of conventional immersion systems, in particular the part 5.1 of the shaft area is formed with an insufficient wall thickness, since after the immersion molds 1 have emerged from an immersion bath 8 (see FIG. 2), the liquid film adhering to the surface runs downwards. which results in an undesirable reduction in wall thickness in part 5.1 of the shaft area 5.

In the immersion system according to the exemplary embodiment and as shown in FIG. 1, the immersion molds 1 are introduced essentially vertically into an immersion bath 8 and moved out of the latter.

With the help of FIG. 2 it becomes clear how the immersion molds 1, which are located on the suspension devices 4 of the belt conveyor 2, are moved into the immersion bath 8 in order to achieve a corresponding wetting of the surface of the immersion molds 1.

As shown in FIG. 3, on the device side, the immersion system is provided with a running rail 10 which is fastened in such a way that the respective immersion molds 1 move or move differently from their previously perpendicular or vertical position. be pivoted. The movement of the immersion mold 1 is easily possible due to the presence of the joint 3.

Due to the fact that the immersion form 1, in cooperation with the joint 3, due to the force of gravity, attempts to return to its vertical position, the race 6 attached to the immersion form 1 presses against the surface of the running rail 10, so that with a corresponding movement of the chain or belt conveyor 2 into the image plane or out of the immersion mold 1 in a rotational movement.

The dipping mold 1 is moved in or out into the dipping bath 8 by means of a corresponding curve shape or movement path of a guide rail 11 which interacts with a corresponding sliding surface 12 of the chain or belt conveyor 2.

4 shows the arrangement of a spray device 13, in the example shown a vortex spray device, with a nozzle 14, with the aid of which a defined opening angle of the spray jet 15, for example of 15 ± 5 °, can be set.

The spray device 13 and the nozzle 14 are aligned so that the particularly critical part 5.1 of the shaft area 5 is wetted with the additional coagulant layer.

In the exemplary embodiment, the concentration of the sprayed-on coagulant layer is the same or to a greater extent than the concentration in the basic mixture, ie. H. the diving pool 8 itself.

4, the spray device 13, including the nozzle 14, is arranged in a fixed manner, and a circumferentially uniform wetting of the immersion mold 1, in particular in the region 5.1, is achieved by the rotational movement of the immersion mold 1 by means of the interaction of the race 6 and the running rail 10. According to further exemplary embodiments, however, it is also possible that, additionally or alternatively, the spray device 13 including the nozzle 14 executes a swiveling movement or two opposing spray devices 13 are provided with corresponding nozzles 14, each of which executes a swiveling movement on a predetermined path , so that even without rotating the immersion mold 1, a uniform wetting and formation of a surface film with coagulant in the given area, for example the area 5.1 of the shaft 5, is possible.

It has turned out to be particularly advantageous that, given the predetermined opening angle of the nozzle 14 of the spray device 13 of essentially 15 ± 5 °, the distance of the device 13 or the opening of the nozzle 14 from the immersion mold 1 is essentially four - Up to five times the diameter in the upper part of the shaft area 5 corresponds to the immersion form 1.

In the exemplary embodiment shown, an already existing continuously operating immersion system can be retrofitted with simple means without there being any kind of restriction with regard to the productivity or the principle mode of operation of such an immersion system.

By changing the distance and / or the opening angle of the nozzle 14 in relation to the corresponding area of the shaft 5, it is possible either to set uniform wall thicknesses over the entire immersion mold 1 or to achieve different wall thicknesses determined in accordance with the respective load requirements .

It has also been found that the risk of damage to surgical and examination gloves produced in this way when the same is removed from the immersion molds 1 as the last essential process step before final processing is significantly reduced, so that there is a reduction in the reject rate. The method for varying the thickness of thin-walled vulcanized diving articles will be described in detail below with reference to the explanation of the exemplary embodiment on the device side.

First, the immersion molds 1, which are located on the belt conveyor 2, are immersed in the immersion bath 8 in a known manner.

With the beginning of Austauchenε and the action of the guide rail 11, which cooperates with the sliding surface 12, the race 6 comes into operative connection with the guide rail 10 and is brought into the corresponding position deviating from the vertical position and set in a rotary movement. Now the spray device 13 is activated so that the spray jet 15 containing coagulant emerges from the nozzle 14. This spray jet 15 strikes the region 5.1 corresponding to the position of the nozzle 14 and forms an additional surface film from the coagulant used.

In the case of a continuous immersion system, it is not necessary for the spray device 13 to be deactivated during the time in which there is no immersion mold 1 in the immediate spray area. This is because, on the one hand, a large part of the sprayed coagulant is returned to the container 16 of the immersion bath 8 and, on the other hand, the homogeneity of the spray jet 15 or the surrounding spray mist (not shown) is improved.

Of course, it is alternatively possible to operate the spray device intermittently if this is necessary for procedural reasons or to maintain certain wall thickness ratios.

It corresponds to the basic idea of the claimed solution that the continuously moving immersion mold 1 emerges from the range of action of the spray jet 15 before a complete one Immersion of the immersion mold 1 from the immersion bath 8 was achieved, so that an undesirable increase in the wall thickness in the hand region 7 is avoided in the specific case.

In one embodiment, which assumes on the process side that the spray device 13 is only activated after the immersion form 1 has completely emerged from the immersion bath 8, the position and orientation of the spray jet 15 with the aid of the nozzle 14 ensures that only the respective ge - Desired area, for example area 5.1, is provided with an additional coagulant layer. For this purpose, it may be conceivable to provide one or more orifices or other measures for specifically directing or influencing the spray jet 15 between the nozzle 14 and the immersion form 1.

The opening angle of the nozzle 14 is WD in FIG. 4; the angle of the longitudinal axis of the dip mold 1 deviating from the vertical is identified by WT.

All in all, it is possible with the invention in a simple manner to selectively vary and / or homogenize the thickness of thin-walled vulcanized diving articles during their manufacture, so that the quality of such diving articles increases and the diving articles can be adapted even to the most varied of applications and loads .

Claims

claims

1. A method for varying the thickness of thin-walled vulcanized diving articles, in particular surgical and examination gloves, the diving articles being produced by coagulant-latex immersion bath film coating of a diving mold and subsequent vulcanization, characterized by the application of an additional coagulant layer on the Immersion form by spraying or brushing in a desired area in order to achieve a higher wall thickness or to homogenize the wall thickness distribution, the additional coagulant layer being applied during the immersion process or immediately after the immersion of the immersion form from the immersion bath and a concentration for the application of the additional coagulant layer is chosen to be less than, equal to or greater than the coagulant concentration in the immersion bath.

2. The method according to claim 1, which also means that a relative movement takes place between the immersion mold and a spraying or coating device during the application of the additional coagulant layer.

3. The method of claim 2, d a d u r c h g e k e n n z e i c h n e t that the dip mold is set in a rotary motion during the spraying or brushing operation and / or the spraying or brushing device executes a partial or full circular movement around the dip mold.

4. The method according to claim 1 or 2, characterized in that the spraying or painting process with the beginning Aus¬ diving the substantially vertically hanging dipping form for surgical and examination gloves from the immersion bath, so that a shaft area of the immersion form or of the respective glove is formed with increased wall thickness or with the same wall thickness in relation to the hand area, but the hand area remains unwetted by the additional coagulant layer.

5. The method of claim 4, d a d u r c h g e k e n n z e i c h n e t that a vortex spray device is used with a predetermined spray opening angle.

6. The method according to any one of the preceding claims, characterized in that the residence time of the substantially vertically hanging diving form in the immersion bath is selected so that there is a minimal wall thickness in the hand area of surgical gloves and examination gloves and with the subsequent formation of the additional ones Coagulant layer by spraying or brushing the wall thickness in the remaining areas is set to maximum resilience with sufficient elasticity of the vulcanized immersion article.

7. The method according to any one of the preceding claims, that the additional coagulant layer is preferably applied during the immersion of immersion forms from an immersion bath of a continuously moving immersion system.

8. The method according to claim 7, characterized in that the relative movement between the immersion mold and spraying or coating device by the continuously working immersion system and the rotary movement for uniform wetting of the immersion form by reshaping the longitudinal movement of the immersion system by means of an at least approximately rota- tion-symmetrical end of the rotatable immersion form is executed.

9. Device for carrying out the method according to one of claims 1 to 8, comprising a fastening device (2, 3, 4) for at least one immersion mold (1) which can be introduced and removed in a plunge pool (8, 16), characterized by a spray device (13, 14) which is arranged such that an additional coagulant layer can be applied to areas (5.1) of the immersion mold (1) during the immersion process or immediately after the immersion process.

10. The device according to claim 9, characterized by a substantially vertically immersible in the plunge pool (8, 16) immersing rotatable dipping form (1), along and by means of a chain or belt conveyor (2) substantially horizontally through the dipping bath (8) is carried out, the additional coagulant layer being applied by means of the spray device (13) to at least part of the dipped area (5.1) when the wetted dipping form (1) begins to emerge, and the dipping form (1) is essentially applied during spraying stationary spray device (13) is set into a rotational movement by means of a fixed rail (10), the rail (10) being in a frictionally operative connection with a race (6) of the immersion mold (1).

11. The device according to claim 10, characterized in that the rail (10) is arranged so that the immersion form (1) has an angle of substantially 8 ° deviating from the vertical position.

12. The apparatus of claim 10 or 11, characterized in that the spray device (13) has a nozzle (14) for forming a spray jet (15) with an opening angle of substantially 15 ± 5 ° and that the spray device (13) in a distance from the immersion form (1) of substantially four to five times the diameter of the shaft area of the immersion form (1) for the production of surgical and examination gloves is arranged.