DE4031943A1 - Sterilisable surgical cloth - with heat bonded absorbent outer thermoplastic layer, impermeable thermoplastic barrier layer and permeable thermoplastic base layer - Google Patents

Abstract

A liq.-impermeable barrier layer of thermoplastic synthetic foil bonded to the outer layer, and a breathing, permeable base layer of thermoplastic synthetic fibre fleece, kind to the skin, bonded to the barrier layer, the outer layer is an unwoven fleece based on a thermoplastic synthetic, e.g. a spun fleece of endless fibres, a staple fibre fleece or pref. a melt-blown fleece of thermoplastic synthetic micro-fibres, and the outer layer, barrier layer and base layer have been bonded together thermally by brief heating of at least one of the layers to temps. in the softening range of the synthetic. USE - The cloth may be a throw-away article. It can be used not only in surgery, but also as non-sterile material in the pharmaceutical, hygiene, electronics and optical industries.

Description

The invention relates to a sterilizable surgical drape with a liquid absorbent Outer layer and one adherent to the outer layer connected liquid-impermeable barrier layer a thermoplastic film and one with the Barrier layer bonded skin-friendly breathable permeable base layer made of a fleece Basis of thermoplastic synthetic fibers.

To prevent contamination are surgical Surgeries as numerous types of surgical drapes Surgical cover, surgical clothing, surgical clothing, surgical gowns, Surgical instrument table cover in use, taking the drape is used immediately or ready-made. Such surgical drapes must be sterilizable. Furthermore is one strives to make the surgical drape economical for the Manufacture single use as a disposable item. To the surgical drapes, however, have special requirements regarding its functionality. It must be drapable, sufficient tear resistance in the Have composite, as well as a sufficient Suction speed and liquid absorption in the absorbent layer and the skin-friendly layer must be abrasion-resistant and lint-free. The cloth must also be impermeable to fluids to penetrate  Fluids during surgery and also the passage of To prevent bacteria. Because the wipes can be sterilized must ensure that the materials used no unpleasant smells during sterilization, e.g. B. Steam sterilization, unfold.

Surgical drapes of various structures are for example from DE-OS 22 27 333, US 36 76 242, DE-AS 21 10 344, DE-OS 35 22 051 or US 46 16 642 become known.

A disadvantage of a number of surgical drapes felt that the liquid-impermeable barrier or Barrier layer are present as an outer layer or the Layers contain materials used in sterilization Develop smells.

The invention has for its object at least one three-layer surgical drape of the generic type by using selected materials economically as Manufacture disposable items while doing the surgical Cloth requirements regarding drapability, Absorbency, barrier function and sterilizability optimal to fulfill.

This object is achieved by a generic sterilizable surgical drape with the characteristic Features of claim 1 solved. According to the invention, the Bond through thermal bonding - thermobonding - thereby achieved, and only that not only for the Barrier layer used a thermoplastic film but also for the outer layer in addition to the base layer a fleece based on thermoplastic synthetic fibers. The The barrier layer thus also forms the base layer with the Outer layer connecting layer, so has in addition to the function the barrier layer also the function of the bond. The Adhesive bond can either over the entire surface or over a Embossing is done selectively in partial areas. The invention thus avoids the use of adhesives and thus the  Adhesive lamination of the individual layers, so that when later sterilization of the cloth no odor nuisance more can arise.

A method for producing a three-layer composite for a Sterilizable surgical drape can be according to the characteristics of claim 19 are performed. Since the Barrier layer on both sides binding and liability mediate and at the same time by the two outer If layers are carried, this can preferably be increased of liability before entering the nip to approximately to the softening temperature of the thermoplastic the barrier layer are heated. Sticking the Barrier layer on the rollers or sagging the two outer layers avoided. to stick one on avoiding the layers on the rollers is also provided that the base layer or the outer layer of a spunbond made of thermoplastic synthetic fibers before entering the Roller gap, if heated, only up to a maximum about 20 ° C below the softening point of the base or Outer layer temperature is heated so that it is still sufficient strength for the passage through the Has nip.

The surgical drape according to the invention from one Multi-layer composite has sufficient tear resistance and resistance to abrasion. The network is through the barrier layer impermeable to liquids and fulfilled hence the function of both preventing puncture of liquids as well as the passage of bacteria. Of another is the surface, i.e. H. the outer layer is sufficient rough, so that the slipping of lying on during the operation Instruments or other supply from the Surface of the cloth is avoided. In particular that is surgical drape also draped and soft.

Advantageous further developments of the surgical drape are characteristic features of claims 2 to 18 can be removed.  

The surgical drape according to the invention is not only dependent on used materials according to different Sterilization methods can be sterilized, but it is also considered non-sterile protective clothing can be used for a variety of purposes, for example for pharmaceutical, hygiene, electronics, Optics industry etc. A particular advantage can be seen in that the non-woven nonwovens used for the outer layer can be both hydrophilic and hydrophobic.

For the skin-friendly base layer, which is also a good one Adhesion to the barrier layer should be suitable in particular spunbonded fabrics based on polyolefin fibers, especially relatively low polyethylene fibers Softening points according to the selected polyethylene or based on polypropylene fibers. Higher temperature resistant Spunbonded nonwovens based on polyester fibers or polyamide fibers can also be used with advantage where the requirements to the tear resistance and abrasion resistance of the surgical drape can be placed particularly high.

As lint-free, abrasion-resistant, skin-friendly nonwovens, spunbond nonwovens made of microfibers made of thermoplastic material, produced by the meltblown process, also referred to as meltblown nonwovens, are particularly suitable. The base layer can be a thin, light fleece with a weight per unit area of about 5 to 30 g / m ² . However, plastic nonwovens made from continuous fibers, possibly also mixed fibers, or plastic nonwovens made from staple fibers, possibly mixed fibers and, in addition to plastic fibers, also containing textile fibers, can be used as the base layer. The basis weight ultimately depends on the application of the surgical cloth. If, for example, adhesive strips are applied during subsequent assembly, the fleece must also be thicker.

The nonwovens can also be made of plastic fibers can be produced, which in the extrusion in addition to the  Plastic also other additives, such as chalk for the Opaque character, colorants, hot melt adhesive properties Thermoplastics to improve the adhesion when Thermal bonding, antistatic agents and / or UV absorbers added can be. When adding hot melt adhesive properties materials are to be designed so that they for example, the adhesion of a polypropylene fleece as Outer layer to a polyethylene film as a barrier layer or increase conversely. That is, this addition of a Plastic having melt adhesive properties to the Molding compound in the manufacture of a nonwoven that acts as an outer layer or can also be used as a base layer, the Adhesion improvement of this outer layer or base layer to the serve barrier layer made of a different material.

It is also possible for the outer layer or base layer used spunbonded nonwovens made of thermoplastic fibers subsequently with an adhesion promoter layer on one side equip to improve the adhesion to the barrier layer. The spunbond nonwoven and the adhesion promoter layer can be used here form a preliminary composite as a cover layer, for example directly in the production of the spunbond nonwoven will be produced. This adhesive layer must consist of one thermoplastic, for example low melting polyethylene or low melting Polypropylene or other suitable thermoplastic Plastics exist, this adhesion promoter layer one should have a lower softening point than that Outer layer or base layer forming spunbond, so that in thermobonding to produce the multilayer composite for the surgical drape has an appropriate liability Softening of this adhesive layer is achieved.

Good adhesion between the three layers of the surgical Cloth is achieved in a simple manner that for Outer layer, the barrier layer and the base layer same plastics can be selected or thermoplastic materials with approximately the same  Softening temperature ranges. Are preferred for the Barrier layer with relative thermoplastics low softening temperature ranges around below 142 ° C. This has procedural advantages for production of the association. For the barrier layer can be beneficial thermoplastic plastic films or thermoplastic Multi-layer films based on polyethylene and / or Ethylene vinyl acetate copolymers and / or ethylene copolymers, Acrylic acids and proportions of acrylamide, which are particularly good Convey adhesion to polyethylene. The EVA copolymers from which the barrier layer is made should have VA contents of about 15 to 40% by weight.

If it is desired that the barrier layer be next to high Water resistance also high at the same time Films should have water vapor permeability Based on thermoplastic polyester and especially based of copolyether esters. The middle class should have a thickness in the range of about 5 to 35 µm, preferably have about 10 to 20 microns.

The middle layer provided as a barrier layer thermoplastic film can also be a Be multilayer film, the barrier film on or on both sides with a lower melting film than that Carrier barrier film is coated. When going through the The nip is then thermobonded with the adjacent ones compatible layers over this on the carrier barrier layer applied thermoplastic layer. For the thermal network must the plastic film of the barrier layer or one on it applied layer in the nip to the Softening range to be heated to melt and so far to become soft that they are mechanical anchoring and / or Welded bond and / or chemical bond with the adjacent layers.

The outer layer is said to be a sponge-like absorber layer form, which can be hydrophobic or hydrophilic. The  preferably used spunbond nonwovens Microfibers made of thermoplastic, so-called Meltblown nonwovens are naturally hydrophobic. Such Nonwovens can, however, additionally use superabsorbents, such as starch and other materials, to make them hydrophilic do. However, the meltblown nonwovens have a high one Absorbance for liquids, making them more hydrophobic Surface to the outside, be liquid-repellent and can still absorb liquids without swelling.

For the outer layer, in particular spunbond nonwovens with higher basis weights are used than for the base layer, namely 15 to 100 g / m ² or more, depending on the use of the surgical cloth.

The outer layer can either consist of only one layer Spun fiber fleece can be made or multi-layered and advantageously consist of layers, with between two Spunbond nonwovens made of microfibers or continuous fibers a layer of superabsorbent in thermoplastic Shape of powder granules or the like is embedded. Such a multilayer outer layer can also in In-line processes are made by first The superarbsorber is then spunbond and then applied is covered with the second spunbonded nonwoven. Here you can the spunbond nonwovens directly during the manufacturing process multilayer outer layer can be processed. Such one multilayer outer layer is soft, drapable, spongy with high absorbency and can be hydrophobic on the surface be.

By using spunbond nonwovens made of thermoplastic Fibers, especially microfibers, for the outer layer and the Base layer, the surgical drape becomes sealable in itself; H. it has a high germ density and it can liquid impervious seams are made by sealing be so that sewing with the thread can be omitted. It is also possible by assembling individual parts  Heat seal in turn on the surfaces of the surgical Apply cloth without the liquid tightness and Endangering germ tightness.

The multi-layer surgical drape according to the invention leaves at relatively low temperatures Thermobonding process by laminating each Layers both successively and preferably also simultaneously produce. Here, a endless roll goods are produced in three layers, which then then assembled, sterilized and individually packaged becomes. Thermobonding can be used for two to eight Layers when passing through only one pair of rollers with smoother Full surface or with embossing rollers for partial composite Point areas are carried out. The rollers have it Temperatures of 80 to 180 ° C depending on the materials used, so that the plastic layers causing the bond except their softening temperature are sufficiently heated. Of the rollers can also be coated with a non-stick coating, for example, be coated with polytetrafluoroethylene, so that they can be heated to higher temperatures without sticking with the continuous materials.

The multilayer composite of the surgical drape is different the materials used according to different Sterilization methods can be sterilized. For polyethylene can gamma sterilization can be used, but not for Polypropylene. However, polypropylenes are for that Steam sterilization is suitable because it is relatively high Have softening point. Polyethylenes, however, are for the Steam sterilization because of its low softening point not suitable.

All plastics are made with EO gas, formalin or formaldehyde sterilizable, but EO gas is too for environmental reasons avoid and also the other gases because of the possible Odor nuisance.  

Steam sterilization is done for environmental reasons prefers. However, this is only for all the plastics with higher softening points can be used.

Because the different sterilization methods are not for everyone According to the invention, plastics are used surgical drape based on a uniform plastic, for example, polypropylene, so that it is easy can be subjected to steam sterilization. This is the one most environmentally friendly sterilization method. Beyond that surgical drapes that are based on a multi-layer composite uniform plastic are made, the advantage that they can be easily recycled.

It is also possible and advantageous to use all layers of the to produce surgical drapes based on polyethylene. This composite can then be sterilized using gamma rays and also easily recyclable. Surgical covers, the layers of which are different Plastics are made, for example, with formalin or Sterilize formaldehyde, especially when combinations of polyethylene and polypropylene in the surgical drape are included.

In the drawing, the invention is explained using examples. Show it

Fig. 1 is a plan view of a surgical drape,

Fig. 2 shows the cross-section AA of FIG. 1,

Fig. 3 shows schematically the lamination process.

The surgical drape of Fig. 1 and 2, on the outer layer III, which as an absorbent fluid receiving layer of a nonwoven web of thermoplastic on the basis of synthetic fibers is manufactured. The base layer I, which forms the skin-friendly, abrasion-resistant protective layer, also referred to as the patient layer, is connected to this outer layer III via the barrier layer II, which forms the barrier layer. The dimensions of the base layer and the barrier layer on two opposite sides are somewhat smaller than the outer layer, so that edge strips 2 remain. However, it is also possible, for example, to have the base layer project on one or both sides at the edge or to have all three layers end flush at the edge. The three layers are firmly bonded to one another via plasticization, for example barrier layer II and softening of the outer layer and base layer by the action of pressure at least in partial areas 3 , see FIG. 1. The action of pressure and solidification of the composite take place by means of rollers when the layers are pulled through a roller nip, as shown schematically in FIG. 3. Rollers 2 and 4 form the nip, the direction of rotation is indicated by arrows. Both rollers can have smooth surfaces or, for example, the upper roller can be designed as an embossing roller with a profiling in order to achieve the selective embossing and hardening surfaces 3 according to FIG. 1. The upper roller 3 can be rigidly mounted, while the lower roller 4 can be pressed hydraulically against the upper roller, so that the contact pressure of the roller and thus the line pressure in the nip can be adjusted. Both rollers preferably have the same diameter. The rollers are heated, for example by means of thermal oil, the heating depending on the working speed and thickness of the composite to be produced and the quality of the materials used being between about 160 to 200 ° C. for the rollers, ie the thermal oil. In the case of very thin individual layers I, II, III and a relatively slow pulling speed, it may be sufficient to achieve the required heating of the layers to be joined and plasticization of the layers simply by contacting the rollers 3 and 4 in the roller gap and thus the necessary connection to reach between the layers for the surgical drape 1 . However, in order to work more economically, to increase the pulling speeds through the nip and possibly also to achieve a sufficient connection, in particular between the layers that have less adhesion to one another, it can be advantageous to at least barrier layer II as a middle layer before entering the Preheat and plasticize the nip, for example by means of infrared emitters or when passing through a hot air section, so that good adhesion of the multilayer composite to be produced is achieved. In addition, it is also possible, for example, to preheat one of the outer layers, namely the outer layer and / or the base layer on its side facing the middle layer, in order to increase the adhesive strength which can be achieved or to emboss and thermobond with low resistance of the heated layers in the roll gap achieve.

An advantageous structure of a surgical drape has for example a base layer as a patient layer from a Meltblown nonwoven made of polyethylene, a barrier layer a polyethylene film and another meltblown fleece Polyethylene as an outer layer. Instead of polyethylene polypropylene can also be used. Such one Three-layer structure is homogeneous, i. H. easily recyclable and easily by one method, namely gamma sterilization or Steam sterilization, sterilizable. Furthermore has one such structure has the advantage that it is externally hydrophobic. This three-layer surgical drape is also sealable and thus in a simple manner, without destroying the seal assemble. One can use such an externally hydrophobic surgical cloth, for example by spraying with Make the wetting agents hydrophilic.

Another advantageous structure of a surgical drape According to the invention, a meltblown nonwoven has as the base layer made of polypropylene, d. H. a spunbond fleece made of microfibers Polypropylene, a meltblown fleece on and as an outer layer  Base of ethylene vinyl acetate or an outer layer of one Meltblown fleece based on polyethylene. As a barrier layer a multilayer film is provided, which is a carrier film Basis of polyolefins, such as polyethylene or polypropylene or Contains polyamide and the one at a lower temperature as an adhesive layer melting from the carrier film a thermoplastic on one or both sides has that is compatible with the base layer or Outer layer. For example, the carrier film can consist of 80% by weight Polypropylene and 20 wt .-% acrylate and on their Base layer facing side with acrylate and its the Outer layer facing side coated with polyethylene be. The adhesion promoter layer can be a relatively low one Have softening temperature, so that when the three layers, namely outer layer, base layer and Barrier layer, the adhesive layers in the nip quickly soften and the adhesive bond between the Effect layers.

Claims (20)

1. Sterilizable surgical cloth with a liquid-absorbing outer layer and a liquid-impermeable barrier layer made of a thermoplastic plastic film and a skin-friendly, breathable, permeable base layer made of a non-woven material based on thermoplastic plastic fibers, characterized in that the liquid-absorbing outer layer is not Woven nonwovens based on thermoplastic materials, such as spunbonded nonwovens made from continuous fibers, staple fiber nonwovens or preferably a spunbonded nonwoven made from microfibers made from thermoplastic (meltblown nonwoven), and the outer layer, barrier layer and base layer through thermal consolidation as a result of brief heating of at least one of the layers to temperatures are connected to each other in the softening area of the plastic used. 2. Surgical drape according to claim 1, characterized in that the outer layer, the Barrier layer and the base layer based on each are made of the same thermoplastic. 3. Surgical drape according to claim 2, characterized in that for the outer layer, the Barrier layer and the base layer as polypropylene Plastic is used. 4. Surgical drape according to claim 2, characterized in that for the outer layer, the  Barrier layer and the base layer as polyethylene Plastic is used. 5. Surgical cloth according to claim 1, characterized in that a meltblown nonwoven made of polyolefin fibers, in particular polyethylene or polypropylene fibers with a basis weight of about 15 to 100 g / m ^{2 is} used as the outer layer. 6. Surgical drape according to claim 1, characterized in that a meltblown nonwoven made of polyester fibers or polyamide fibers with a basis weight of 15 to 100 g / m ^{2 is} used as the outer layer. 7. Surgical drape according to claim 1, characterized in that a multi-layered of two a layer of super absorbers between them including meltblown nonwovens made of thermoplastic Plastic-built outer layer is provided. 8. Surgical cloth according to one of claims 1 to 7, characterized in that a spunbond fleece made of microfibers made of thermoplastic material (meltblown fleece) with a basis weight of about 5 to 30 g / m ^{2 is} used for the base layer. 9. Surgical drape according to one of claims 1 to 7, characterized in that for the base layer a spunbond made of continuous fibers made of thermoplastic material, optionally also mixed fibers, with a basis weight of about 10 to 30 g / m ^{2 is} used. 10. Surgical cloth according to one of claims 1 to 7, characterized in that for the base layer a staple fiber fleece or staple fibers, optionally mixed fibers and in addition to synthetic fibers also containing textile fibers, based on thermoplastic plastics with a basis weight of 6 to 30 g / m ² is provided. 11. Surgical drape according to claim 1, characterized in that a film as a barrier layer made of a thermoplastic with a Softening temperature below 142 ° C is used. 12. Surgical drape according to claim 1, characterized in that as a barrier layer Multi-layer film with a carrier film based Polyolefins such as polyethylene or polypropylene or one other thermoplastic, such as polyamide, is provided with a lower one Temperature as the carrier film melts Bonding layer for thermobonding on or is provided on both sides. 13. Surgical drape according to claim 12, characterized in that an adhesion promoter layer Based on ethylene vinyl acetate copolymers or acrylates or low melting polyethylene or low melting polypropylene or polyester for the Barrier layer is provided. 14. Surgical drape according to one of claims 1 to 13, characterized in that the barrier layer has a thickness from about 5 to 35 microns, preferably 10 to 20 microns. 15. Surgical drape according to one of claims 1 to 14, characterized in that a base layer of a meltblown nonwoven made of polyethylene or polypropylene with a basis weight of about 5 to 30 g / m ² , a barrier layer made of a polyethylene film or polypropylene film with a thickness of about 10 to 30 microns and an outer layer of a meltblown nonwoven made of polyethylene or polypropylene with a basis weight of about 15 to 100 g / m ^{2 is} provided. 16. Surgical drape according to one of claims 1 to 14, characterized by a base layer of a meltblown nonwoven made of polyethylene or polypropylene with a basis weight of about 5 to 30 g / m ² , a barrier layer made of a multilayer film with a carrier film based on Polyethylene or polypropylene or polyamide and an adhesion promoter layer for the outer layer and / or base layer and an outer layer made of a meltblown nonwoven based on ethylene vinyl acetate copolymers with a basis weight of about 15 to 100 g / m ² . 17. Surgical drape according to one of claims 1 to 16, characterized in that for the base layer or Outer layer of meltblown nonwovens based on thermoplastic Plastics are used that are made from molding compounds are in addition to the thermoplastic additives such as chalk, colorants, hot melt adhesives, to improve adhesion in thermobonding, Contain antistatic agents, UV absorbers or the like. 18. Surgical drape according to one of claims 1 to 17, characterized in that for the outer layer or Base layer meltblown nonwovens based on thermoplastic Plastics are used that are one-sided with their the side to be connected to the barrier layer Adhesion layer are equipped, the one has a lower softening point than the meltblown nonwoven. 19. Method of making a multilayer composite for use as a sterilizable surgical drape with a liquid-absorbing outer layer and one with the outer layer bonded firmly liquid-impermeable barrier layer from a thermoplastic film and one with the Barrier layer bonded skin-friendly breathable permeable base layer made of a fleece based on thermoplastic synthetic fibers, thereby  characterized in that as a liquid absorbent Outer layer of non-woven based nonwovens thermoplastics, such as spunbonded nonwovens Continuous fibers, staple fiber fleece or preferred Spunbond nonwovens made of microfibers made of thermoplastic Plastic (meltblown fleece), are used, the Outer layer, base layer and barrier layer either approximately the same softening temperatures of the used Have plastics or a barrier layer with a Plastic, one opposite the outer layer and Base layer has a lower softening temperature or between the layers of adhesion promoter layers lower than the adjacent layers Softening temperature of the plastic are provided, and the layers for joining in pre-joints or simultaneous connection by one of two to one Temperature of about 160 to 200 ° C heated rollers formed nip and performed by heating and Melt at least part of the inner Plastic layers thermally to an adherent Multi-layer composite are solidified. 20. The method according to claim 19, characterized in that the barrier layer before the Run into the nip almost to the Softening temperature of the thermoplastic the barrier layer or the one on the barrier layer applied adhesive layer is heated.