DE2126897C2 - Adhesive tape for medical purposes - Google Patents

Description

a) a randomly distributed mixture of 10 to 50% by weight of wood pulp fibers (12). 5 to 40 wt .-% hemp fibers (14) and 4 to 20 wt .-% rayon fibers (16), these Fibers do not exceed a length of 13 mm, and

b) from 20 to 60% by weight of a flexible binder (18) which is distributed in the mixture,

UH web (10) being micro-folded to a length that is less than> 96% of its unfolded length

2. Adhesive tape according to claim 1, characterized in that the binder (18) is a crosslinked Polyethyl acrylate is.

3. Adhesive tape according to claim 1 or 2, characterized in that the self-adhesive acrylic adhesive (22) is porous.

4. Adhesive tape according to one of claims 1 to 3, characterized in that the adhesive (22) has a crosslinked mixture of a 2-ethylhexyl acrylate-Vin> lacetatco; polymers with 2-ethylhexyl acrylate-n-tert-butyl acrylamide copolymer ° n is.

5. Adhesive tape according to one of claims 1 to 4, characterized in that "leave the adhesive-free The surface of the web (20) has a release coating (24).

6. Adhesive tape according to claim 5, characterized in that that the release agent coating (24) consists of stearyl methacrylate acrylonitrile copolymer.

7. Adhesive tape according to one of claims 1 to 6, characterized by a web (10) consisting of a randomly distributed mixture of? 'i to 40% by weight wood pulp fibers, 10 to 30% by weight Hemp fibers and 6 to 15% by weight rayon fibers, all fibers having a length less than 9.5 mm own and by 20 to 50 wt.% Crosslinked Polyäthylacrylatbinder, which in the mixture is distributed, are connected to one another, the web (10) being 95 to 90% of its original length is micro-folded.

The present invention relates to dressings and tapes for medical purposes which consist of a Carrier web or a backing, a self-adhesive adhesive on one side thereof and preferably consist of a release agent coating on the other side of it = In particular, the invention relates an inexpensive medical tape that has many of the desirable properties that are common include more expensive fabric-based ribbons, but made from an inexpensive blend of short fibers including wood pulp, hemp and rayon fibers.

Previous attempts to make the back of medical tapes based on paper, to take advantage of the low cost of the wood pulp component, such as that disclosed in U.S. Patent 30 55 496 are described, did not lead to the desired success. Compared with a back side out a woven cloth, for example, is the cost savings associated with paper-based backing are considerable.

Compared to a fiber fleece backing as shown in the US-PS 31 21 02! is described, div cost savings are not so significant, but has this back insufficient uniformity, especially with regard to wedge, flexibility, tear resistance and like that. During paper backs, the unevenness problems coped, had to do this in

; i in terms of flexibility, resilience and softness up to compromised to an undesirable extent to the required To achieve strength.

GB-PS 8 79 885 describes the impregnation of paper with crosslinkable alkyl acrylate copolymer latex. This impregnated paper serves as a carrier material for pressure-sensitive adhesives, so that the Composite material can be used as a self-adhesive masking tape.

2ϊ The object of the present invention is to provide a flexible porous tape for medi umsehe purposes which can be produced at low cost and which has essentially the properties of expensive products with a woven or non-woven backing. In particular, the tape should contain paper and eliminate the flexibility and compliance problems of the previously known paper-backed tapes and have increased tear resistance properties.

This object is achieved by the adhesive tape according to claim 1.

In the subclaims are preferred embodiments described.

The tape according to the invention has a specially formed and treated i'ahn, which with a self-adhesive, porous adhesive is coated on one side and preferably on the other side have a release agent coating; The special web contains a short fiber one. WahlK, distributed mixture from wood pulp. Hemp and rayon barracks. the with the help a flexible binding agent are connected to one another. The treatment includes a linear micro-fold the web, which gives it a substantial ductility is given without any real creping taking place.

V) The wood pulp keeps costs down, the hemp fibers give the web strength, while the rayon fibers are supported by the microfold treatment for softness. Flexibility and compliance contribute. The shortness of the fibers gives excellent tear properties.

The advantage of the tape of the invention is that it clean, flexible, resilient, light in weight, easy to handle, breathable and hypoallergenic. The tape is easy to tear, but also substantial stretchable, with the resistance to tearing being significantly improved in normal use.

The invention is explained in more detail below with the aid of a preferred exemplary embodiment.
The web, which can have a thickness of 0.05 to 0.31 mm or, if desired, other values, consists of a mixture of 10 to 50%, preferably 20 to 40%, of common wood pulp fibers or those suitable for papermaking, 5 up to 40%, preferably 10

to 30%, hemp fibers and 4 to 20%, preferably b to 15% rayon fibers, all fibers having a length essentially no greater than 12.7 mm and is preferably less than about 9.5 mm, for example 1.6 to 7.9 mm. The fibers are uniform Randomly distributed in the web and by a flexible binder, such as a soft crosslinkable binder based on rubber, for example an acrylate binder, connected with each other. The binder is in an amount of 20 to 60%, preferably about 30 to 50%, available. All quantities of the substances in the web are given as percentages by weight, as in the following, in relation to the finished web.

In a particular embodiment, the web have a thickness of about 0.10 to 0.125 mm and of a randomly distributed mixture of about 29% wood pulp fibers a length of about 3.2 mm, about 21% Manila hemp fibers of about 635 mm in length, about 10% rayon fibers (a mixture of regenerated Cellulose fiber with 1.5 and 3 denier) a length of about 6.35 mm and about 40% cross-linked! Polyethyl acrylate exist as a binder. This embodiment of the Web can be made by the wet papermaking technique using the polyethylene acrylate binder is crosslinked using a diammonium phosphate catalyst.

Paper webs with the desired composition are commercially available.

Flexibility increased around the web, yielding It will be able to give stretchability and softness microfolded to densify it without significant creping. Procedure for ) Implementation of this treatment are known and for example in US Pat. No. 2,624,245 and 3,055,496 described.

The microfolding treatment should be sufficient to achieve linear compression (decrease in length,

κι without an increase in thickness) of at least 4% (i.e. about 96% of the original length), preferably about 5 to 10% (i.e. about 95 to 90% of the original Length). The treatment results in an extensibility or elongation (the property without

i) tearing to be stretchy and released into the return to original shape) of at least 8%, for example about 10 to 15% of the compressed Length. This is because the paper impregnated with a flexible binder itself is one has a certain extensibility and, in combination with the micro-folding, the surprisingly good extensibility that gives. Results that with a standard Paper of the composition according to the invention using the folding technique of the above-mentioned US Pat 30 55 496 (with no moisture added to the web prior to compression), are summarized in the following table

Before the Squeeze Thickness, mm 0.10-0.125 Weight, g / m ² 33.5-40.5 Elongation, % (running direction) 5-7 Tensile strength, kg / cm ¹ (Running direction) 0.49-0.63 Tear strength, g (Transverse direction) 50-80

After this
Squeeze

After compression, the web is characterized by a high degree of softness, flexibility and Compliance and has the required tensile strength. They can also be used as desired be torn clean.

As an adhesive that is applied to the compressed web is to be applied, any conventional, preferably porous, self-adhesive adhesive that is used for Manufacture of ribbons. Adhesive bandages and the like used in the medical field are used so will. Suitable adhesives are, for example, self-adhesive acrylate-based adhesives, which are currently used for tapes for medical purposes. Natural or rubber based adhesives synthetic rubber are not anchored to the paper in a satisfactory manner. Using a Primer coating for attaching the adhesive is undesirable as this tends to stain the product to stiffen.

One form of pressure sensitive adhesive that can be used is a pure rubber copolymer of isooctyl acrylate and acrylic acid in a ratio of 94: 6, as described in US Pat. No. 2,884,126 (Reissue 24,906). A method of achieving the desired and necessary microporous structure, in order to obtain a high moisture vapor permeability, for example about 50 to 500 g per 645 cm ² in 24 hours, is described in US Pat. No. 3,121,021.

0.09-0.114

37-44

10-15

0.35-0.63
100-140

Preferred adhesives are the 2-ethylhexyl acrylate-vinyl acetate copolymer or a mixture of this copolymer with the 2-ethylhexyl acrylate-n-tert-butyl acrylamide copolymer, wherein the mixture is crosslinked or cured, a commercially available suitable one Catalyst such as an organic complex zirconium-containing catalyst is used. Other adhesives that can be used are disclosed, for example, in US Pat. No. 2,877,141, 29 09 278, 33 07 544 and 33 25 459 described.

The adhesive can be applied to the compressed web by conventional means, for example by transferring, spraying, using an applicator roller or the like. The adhesive mass will generally be firmly attached to the web, usually not requiring a primer to to anchor the crowd. The volatiles can be quickly removed from the mass as soon as they applied -st so that the solids are not too deep penetrate or bleed from the compressed web.

In a typical transfer technique, the adhesive mass is transferred from a solvent to a removable paper with a heat-resistant, insoluble anti-stick surface, for example one with Silicone release coated carrier, cast. It is passed through a warming cabinet to remove the Remove solvent and if necessary the mass

to blow and harden. The compressed microfolded paper web of the invention is then layered on top of the mass by pressing on it at the end of the warming cabinet while the Silicone-coated paper is eventually removed.

If the mass is blown up by spraying, the volatile constituents contained therein become squeezed off and the mass is applied to the compressed web in a tough form. the viscous mass is anchored during the subsequent heat treatment, so that a strong almungs capable About / ug results.

The amount of adhesive will vary depending on the particular adhesive, the ultimate use of the product, and the like. In a typical embodiment for a medical tape, the weight of the dry adhesive layer can be in the range of about 0.135 to 0.54 kg / m '. A typical porosity / Wo ^ crdsm ^ idurchlijSS ^ VcM) for Hip 7HS3mmpni7P- pressed web after application of the preferred adhesive mentioned above can be in the range of 50 to 100 g per 645 cm ² per 24 hours.

Fine lubricant or release agent coating is im generally necessary because short-fiber, wood-pulp-containing mixtures have a relatively low level of stripping or have cleavage resistance. Therefore, in order to obtain a low peel force or unwind tension, When the tape obtained is unwound from a roll of this material, it becomes a coating onto the adhesive-free surface. after or simultaneously with. preferably after the application of the Self-adhesive applied

Suitable coatings are described in US Pat. No. 2,913,355, others are for the person skilled in the art can be seen and their suitability can be tested by means of simple experiments. The preferred coating consists of stearyl methacrylate-acrylonitrile copolymer. that is suitably hardened. Silicone-based coatings, in particular, a quick set release coating was significant for purposes of the invention less satisfactory.

Conventional methods can be used to apply the release coating. For example, this layer is preferably applied in a gravure roller process a low solids content, e.g. less than 20%. owns, she can also access the Surface of the compressed web can be sprayed with a large amount of the solvent During the spraying process, the solids concentration is evaporated and only small amounts of the evaporate Solids penetrate into the interior of the web. In this way the surface of the web is covered with individual Particles of the release agent are covered which are attached to the web surface.

The present invention is described below with reference to the exemplary embodiments shown in the figures explained in more detail

F i g. Figure 1 shows an enlarged cross-section of a portion of the pulp hemp rayon web prior to the requirement compress it.

F i g. Figure 2 shows the web after micro-folding and application of the self-adhesive and the back Coating.

F i g. 3 shows schematically the production of the inventive Product.

The starting material for the production of Products according to the invention consists in a particular embodiment of a web 10, the one Thickness of about 0.127 mm and a mixture of about 29% wood pulp fibers 12 with an average Length of about 3.2 mm, about 21% ■> Maniia hemp fibers 14 with an average Length of 6.35 mm and about 10% rayon fibers 16 with an average length of about 6.35 mm, which consists of 40% crosslinked Polyäthylcnacrylatbinder 18 are connected to each other. After this

ίο Compression using the micro-folding method U.S. Patent No. 3,055,496 (but with no moisture added prior to compressing the web the mixture of fibers appears as a compressed web 20 as shown in FIG.

Since the fibrous components un <) the Bahnaus cuts in Fig. I and 2 not necessarily plotted to scale with one another, it should be noted that the thickness of the web is about 0.127 mm in Fig. I has decreased to about 0.113 mm in Fi ε 2.

The length of the track has also decreased by about 8%. As a result, the elongation is or Extensibility increased from about 6 to about 12%

The compressed web 20 has a self-adhesive 22, for example hardened 2-ethylhexyl-

acrylate-vinyl acetate copolymers with 2-ethylhexyl acrylate-n-tert-butyl acrylamide copolymers as a coating on one side. On the other side is a release agent coating 24, for example from a crosslinked blend of stearyl methyl acrylate acrylonitrile copolymer.

A method / for making the product of FIG. 2 from web 10 of FIG. 1 is in FIG. 3 shown. Roll 26 represents the starting web 10, which as a special embodiment is a specially composed Can be paper. When it is unwound, it is passed over a guide roller 28 and then into the Gap 30 occurs between the non-yielding surface 32 of the heated drum 34 and the resilient outer rubber surface 36 of a relatively thick, compact. Elastic band 38 is formed will. The belt 38 is against the surface 32 of the drum 34 with the aid of a holding roller 39. a SnannroMe 40 and a floor guide roller 42 held.

When the tape 38 is guided over the holding roller 39, its outer surface 36 follows a convex, its inner surface follows a concave path with the result that the outer surface 36 is strained at C. and is stretched. The outer begins accordingly

so surface 36 to follow a concave path if that Belt 38 passes the nip 30 -nd the surface 32 of the drum 34 instead of the surface the holding roller 39 begins to follow so that the surface 36 at V shortens or contracts

As detailed in connection with FIG. 4 of US Pat. No. 3,055,496, the web tends, due to the differences between the low coefficient of friction of surface 32 on drum 34 and the high coefficient of friction of surface 36 of belt 38 on the Surface 36 to adhere and slide on surface 32. This compresses the web in the longitudinal direction, ie in the machine direction. Sufficient pressure is exerted in relation to the web surfaces to avoid curling or creping and to keep the web surface essentially flat and parallel to one another.
The life of the belt 38 is increased by cooling

with the help of water sprayers 44 and 46 and if desired by passing the Etandes through a Water bath 48 in a container 50 is enlarged. The water is removed from the belt 38 with the aid of nip rollers 32 and 54 removed, which are set so that the cooling water except for small traces of the tape Will get removed.

After the compressed web, now as in FIG. 2 denoted by 20, the surface 32 of the Leaves drum 34, it runs over a guide roller 56, position adjusting rollers 58, 60 and 62. DV-. the latter holds the Web 20 flat when it is passed over a radiant heater 64 that provides any necessary drying completed.

The preferred adhesive Acrylatklebemittel 66 is transferred from a container 68 via a partially submerged transfer roller 70 on one of these light-contacting roller 72 which applies thereof the lower surface of the web 20 feerühr · while the Kl§b? T ° ff ⁿ "f. The volatiles content is reduced or eliminated almost immediately to avoid excessive penetration of the adhesive 66 into the web 20. This is facilitated by an infrared emitter 74 positioned adjacent the roll 72 and below the web.

The preferred backsheet is sprayed onto the web by means of a nozzle 76. There already a large part of the solvent evaporates during spraying, is the solids concentration, which can initially only be 5 to 10%, increased considerably, so that only small amounts of the

ίο Release agent penetrate into the web. The on this Web 20 coated on both sides is then passed through a curing oven 78, where curing temperatures, for example 65 to 205 ° C, can be maintained.

The cured product is then rolled up on a roller 80 for further use. It can be before or cut into any desired width after being rolled onto roll 80. In the cross-section you can see that finished product as shown in Fig.2. Since Hnl7.schliffn. <; Em predominate, it can be used as a band with Paper back can be considered for medical purposes.

1 sheet of drawings

230225 / **

Claims (1)

Patent claims: 1. Adhesive tape for medical use made from a sheet of micro-folded paper and a flexible binder, with the web on one surface with a pressure-sensitive acrylate adhesive is coated, characterized in that that it, in each case related to the finished web, from