FI80636B - Sterilization bag - Google Patents

Description

1 80636

Sterilointipueei

The invention relates to a disposable, plastic multilayer film and a sheet of paper joined together in a sterilization bag, the material of which of at least one layer of the plastic multilayer film is a thermoplastic thermoplastic such as polyester or polyamide.

Hospital infections are controlled by sterilizing equipment used in hospitals such as Bandages and Instruments, mainly by steam etherification. In order to be sterile at the place of use, the devices must be packed in a single-use package before sterilization, sterilized in a sealed package and opened only at the time of use. In the past, textile wrappers and paper bags have been used in hospital sterling, but nowadays, bags made of plastic multilayer film and a sheet of paper are commonly used, in which the paper passes through sterilizing steam. The advantages of such a plastic paper bag are easy sealing by sealing, transparency and good bacterial protection.

When using a sterilizable plastic paper bag, the problem is to find bag materials that are strong enough and at the same time resistant to steam sterilization. After sterilization, the items to be sterilized and the inside surface of the bag remain sterile until the package is opened. Instead, the outer surface of the bag comes into contact with surrounding bacteria or the like and becomes contaminated. When such a bag is opened, the plastic multilayer Ivo should be detached from the paper over the entire area of the release seam so that it only touches the sterile inner surfaces of the paper or multilayer film when the product is taken. However, because the multilayer film often tears from the seam area, pieces of plastic are left on the surface of the paper, the surface of which is not sterile and thus may contaminate the product.

2 80636

When the sterilization temperature of the bag is normally as high as 134 ° C, it is very difficult to find multilayer film plastic materials which do not tear from the area of the release seam of the plastic paper bag in the above-mentioned manner and at the same time withstand the sterilization temperature of about 134 ° C. Thus, in order for hospital equipment to remain sterile, it is essential that the plastic multilayer film of the bag be mechanically strong, heat-resistant and bacteria-tight, and that its seams withstand both sterilization pressures and mechanical stresses caused by handling.

Until now, polypropylene (PP) has been used as the sealing layer for the multilayer film of the sterilization bag, which is still laminated with oriented polyester, usually polyethylene terephthalate (PETP), due to the thermal strength of the bag. The general commercial quality in sterilization bags is ESP 12/50 laminated with 12 μm thick PETP film and 50 μm thick PP mono film. The films are usually made by adhesive lamination, in which case a laminating adhesive is applied to the PET film, and the adhesive-coated PET film is pressed together with the PP film.

This type of multilayer film, in which polypropylene is used as the sealing plastic, has poor tear strength because the polypropylene crystallizes brittle from the sealing area of the bag, where it receives heat during the bag-making step as well as during sterilization processes.

U.S. Patent No. 4,276,922 discloses a bag having a plastic film formed of a transparent, heat-resistant material, such as coated or laminated polyester <PETP> or polyamide.

The object of the present invention is to provide a sterilizable, disposable plastic paper bag by means of which said disadvantages can be eliminated. The invention is then characterized by what is stated in the preamble of the claims. It has been found that a tear film having a strong tear strength and a resistance to steam sterilization, a plastic multilayer film and a sheet of paper bonded together by a sheet can be obtained by laminating a thermoplastic thermoplastic such as polyester, polyamide, etc. with a film containing such elastomer. As mentioned above, crystallization of polypropylene upon sterilization causes the multilayer film to become brittle and its tear strength to deteriorate. A film to be laminated with a heat-resistant thermoplastic such as polyester, polyamide, etc., which contains a mixture of elastomer with polypropylene or propylene copolymer, does not crystallize as easily as sterilized as pure polypropylene, so it retains the strength of the multilayer film despite heat-sterilization treatment.

Thus, a polyester, polyamide, etc. can be used as the heat-resistant, i.e., high-softening, gas-tight, and strong coating layer of the multilayer film. Polyester, especially biaxially oriented polyethylene nitrephthalate, is preferable. Polyamide is less preferred because, despite its heat resistance and strength, it absorbs the moisture of sterilizing steam and curls the laminate film.

Any elastomer compatible with polypropylene or a propylene copolymer is suitable as the elastomer of the new blend layer of the multilayer film. Such elastomers include ethylene propylene rubbers, ethylene propylene diene rubbers, ethylene vinyl acetate rubbers, ethylene methyl acrylate rubbers, butyl rubbers and diene rubbers, and their suitably chlorinated, sulfonated and chlorosulfonated derivatives. A suitable elastomer is, for example, ethylene vinyl acetate rubber (EVA). Since the addition of the elastomeric portion improves the tear strength of the multilayer film but somewhat reduces its thermal crystallinity, the elastomeric portion of the layer containing the elastomer blend with polypropylene or propylene copolymer 4,80636 is generally between 10 and 70% by weight, preferably between 20 and 50% by weight.

The polypropylene or propylene copolymer component of the blend may be a homopolymer of suitable isotacticity and molecular weight or a copolymer suitably modified with other comonomers. The criterion in this case is the thermomechanical properties given to the mixture by the polypropylene or propylene copolymer. The proportion of polypropylene or propylene copolymer in its mixture with the elastomer is generally between 30 and 90% by weight, preferably between 50 and 85% by weight.

The above-mentioned mixture of elastomer with polypropylene or propylene copolymer represents a basic embodiment of the invention. Thus, depending on the desired properties, other components, preferably other compatible thermoplastics, elastomers or conventional additives for plastics, can also be added to the mixture.

The layer to be laminated with a heat-resistant thermoplastic layer, such as a polyester or polyamide layer, containing a mixture of elastomer with polypropylene or propylene copolymer may be a single layer, consisting only of a homogeneous mixture of propylene homo- or copolymer and elastomer with possible additives. A separate heat-sealable layer with the inner or paper is then not required, because the mixture of elastomer with polypropylene or propylene copolymer itself melts at a lower temperature than heat-resistant, thermoplastic polyester, polyamide, etc., and thus seals in the paper sheet of the sterilization bag. However, the layer to be sealed with the heat-resistant thermoplastic is preferably a multilayer film, in which case a separate heat-sealable layer, e.g. a polyolefin such as polypropylene or a propylene copolymer, can be combined with a layer of elastomer blend with polypropylene or propylene copolymer. As the reinforcing and adhesive layer between the alloy layer and the heat-resistant layer of thermoplastic polyester, polyamide, etc., a strong and sufficiently heat-resistant plastic such as polypropylene or propylene copolymer can be used.

As mentioned above, the plastic multilayer film of the sterilization bag can be made of two films, on the one hand a heat-resistant thermoplastic film such as polyester, polyamide, etc., and on the other hand a film containing an elastomer mixture with polypropylene or propylene copolymer, preferably by adhesive lamination. According to a preferred embodiment, a laminating adhesive is applied to a polyester film, e.g. a polyethylene or polybutylene terephthalate film having a thickness of about 8-16 [mu] m, preferably about 12 [mu] m, in a laminating machine and then the coated polyester film is pressed together at the end of the laminating with a film having a thickness of about 30 to 60, preferably about 40. After a few days, the multilayer film reaches sufficient bond strength, after which it is cut to a suitable width to make the bag.

The thickness of the plastic multilayer films of the sterilization bags according to the invention is preferably between 30 and 70, preferably between 40 and 60. It should be noted that due to the strong and heat-resistant alloy layer, the thickness of the multilayer film can be reduced by up to about 15-20%, i.e. from about 60 to about 50, without major disadvantages.

Most preferably, the film containing a mixture of elastomer with polypropylene or propylene copolymer to be laminated with a heat-resistant thermoplastic film, such as a polyester or polyamide film, is three-layered, with said elastomeric mixture of polypropylene or propylene copolymer as the middle layer. The advantage in this case is that a particularly suitable sealing plastic can be used as the lowest layer and a plastic that adheres as efficiently as possible to, for example, polyester, polyamide, etc. The excellent multilayer film has achieved excellent results in terms of laminate tearability. When the weakest point of the package is paper and the seams of the plastic multilayer film no longer tear, the multilayer film according to the invention has made it possible to reduce the thickness of the layer containing said mixture and at the same time the entire bag.

The paper used in the sterilization bag according to the invention is a bleached kraft paper meeting strict standards, which has been specially developed as a raw material by steam sterilization bags. Sterilization suits are made with special bag machines in which the multilayer film is sealed to the paper. The sealing blades are heated to a temperature above 200 ° C and are milled in the shape of a seam, which generally comprises rounded edges to facilitate opening of the bag. The widths of the bag are between 50-400 mm and the lengths between 150-600 mm. Sachet bags are also used.

Figure 1 shows a partial side view of a seam structure of a sterilization pouch according to a preferred embodiment of the invention; Figure 2 shows a top view of a sterilization bag according to the invention.

The etherification package shown in Figure 1 comprises a sealed bag structure of a plastic multilayer film 2 and a sheet of paper 1. The plastic multilayer film 2 consists of four layers 3-6 made so that the polyester film 3, which is preferably a biaxially oriented polyethylene terephthalate film, is glued laminated with a three-layer film 4/5/6, the middle layer 5 of which is a mixture of ethylene vinyl acetate elastomer or polypropylene polyester and layers 4 and 6 surrounding this middle layer are polypropylene or propylene copolymer. The lamination is effected by applying to the polyester film 3 a lamination adhesive which is colored to indicate airtightness and then compressing the polyester 3 coated with the lamination adhesive together with 7 80636 PP / PP + elastomer / PP film 4/5/6. The three-layer film 4/5/6 into which the polyester film 3 is laminated is preferably 40 μm thick, i.e. about 20 X thinner than the corresponding prior art PP monolayer film, wherein the thicknesses of both polypropylene or propylene copolymer layers 4, 6 and the blend layer 5 are all about 13 .mu.m, i.e. make up one third of the thickness of the three-layer film in question. The inner, i.e. sealing layer 6 is preferably a propylene copolymer for sealing. The proportion of elastomer in the mixture is preferably about 40% by weight. A second sterilization bag was also made in which the thickness of the elastomer mixture was reduced to 1/4 of the thickness of the PP / PP + elastomer / PP layer to find out the effect of the thickness of the mixture.

The plastic multilayer film 2 prepared by adhesive lamination was then sealed to the paper 1. The temperature of the sealing blades was above 200 ° C and the shape of the joint was milled into them. In Fig. 2, the cutting means 7 is placed between a sheet of paper 1 and a plastic multilayer film 2. Thereafter, the plastic multilayer film 2 is sealed to the paper sheet 1 so that the paper sheet 1 and the film 2 are stretched around the means 7.

The bag 1, 2 with its means 7 is then sterilized, preferably with steam, the temperature of which may rise to 134 ° C. The steam penetrates through the porous paper and sterilizes the interior of the bag 1, 2 and the device 7. The paper 1 is of such a quality that it is permeable to water vapor but not bacteria, so the bag remains sterile inside until opened.

The opening takes place at the place where the device 7 will be used. The bag 1, 2 can be opened from its top seam 9 or it can be opened by completely removing the plastic multilayer film 2 or the paper sheet 1, whereby the device is left to rest on the sterile paper sheet 1 or the multilayer film 2, respectively, in a suitable area of use. The plastic multilayer film contains, as a single layer, a mixture of elastomer with polypropylene or propylene test 80636 polymer, so that it is strong enough to be completely detached from the paper sheet 1. Therefore, no paper with a contaminated outer surface remains in the paper sheet 1.

In the experiments, the 40 / μm thick PP / PP + elastomer / PP film and the polyester laminate containing 1/3 of the mixture were found to peel off the paper without tearing, while 44% of the control laminates (ESP-1250) were torn.

In the second experiment, in which the strength of the elastomer mixture was reduced to 1/4 part, 40 [mu] m thick PP / PP + elastomer / PP film and polyester laminate resulted in tears of 10 X and a reference laminate of 64 X. Both experiments were performed on steam sterilized packages.

Claims (19)

9 80636 A disposable sterilization bag sealed together with a plastic multilayer film (2) and a sheet of paper <1), wherein at least one layer (3>) of the plastic multilayer film <2> is made of a heat-resistant thermoplastic such as polyester or polyamide, characterized in that at least one layer of the plastic multilayer film (2) (5) the material is a blend of elastomer with polypropylene or propylene copolymer. Sterilization bag according to claim 1, characterized in that the elastomer content of said mixture is 10 to 70% by weight, preferably between 20 and 50% by weight and more preferably about 40% by weight. Sterilization bag according to Claim 1 or 2, characterized in that the elastomer is ethylene vinyl acetate. Sterilization bag according to one of the preceding claims, characterized in that the heat-resistant thermoplastic is a polyester, preferably a biaxially oriented polyethylene terephthalate. Sterilization bag according to one of the preceding claims, characterized in that the plastic multilayer film <2> in addition to the above-mentioned layers <3, 5) contains an inner or sealing layer <6>, which is preferably a propylene copolymer. Sterilization bag according to one of the preceding claims, characterized in that the plastic multilayer film comprises, in addition to the above layers, an intermediate layer (4) between the heat-resistant thermoplastic layer <3> and the layer (5) containing said mixture, which intermediate layer (4) is preferably polypropylene. 10 80636 Sterilization bag according to one of the preceding claims, characterized in that the outer layer (3) of its plastic multilayer film <2) is biaxially oriented polyethylene terephthalate, the second outer layer <4) is polypropylene, the second inner layer (5) is a mixture of elastomer and polypropylene. or with a propylene copolymer, and the inner, i.e. sealing layer <6> is polypropylene or propylene copolymer. Θ. Etherification bag according to one of the preceding claims, characterized in that the outer layer (3) has a thickness of 8 to 16 μm, preferably about 12 μm, and the total thickness of the inner layer (s) (5 / 4,5,6). is 30 to 60, preferably about 40. Sterilization bag according to Claim 8, characterized in that the thickness of the mixture layer (5) forms approximately 1/3 of the thickness of the inner layers (4,5,6). Sterilization drip according to one of the preceding claims, characterized in that the sheet of paper (1) used therein is bleached kraft paper which is resistant and permeable to water vapor but impermeable to bacteria, 1. Eng & ngeeteri1iseringspäse, varmförseglad ur en toy-skiktsfilm (2) av plast och ett ett pappersark (1) »Väre mäng-skiktsfilm (2) har ätminstone ett skikt (3) av ett Värmebe-ständigt thermoplastmaterial säsom polyester ell®r polyamide, kännetecknad av att ätminstone ett andra skikt <5) av mäng-skiktsfilmen (2) av plast bestär av ett material »som är en blandning bestäende av en elastomer och en polyPr ° Penhomopo— lymer ell-copolymer. 2. The sterilization method according to the invention is 1 to 10% by weight of an elastomer and in the range of 10 to 70% by weight, 20 to 50% by weight and about 40% by weight. lt 80636 3. A sterilization process according to claims 1 or 2, which comprises the use of ethylene and ethenyl acetate rubber. 4. The sterilization method is preferably made of a patented film, which can be coated with a color-coated thermoplastic or polyester, or a polyethylene terephthalate. 5. Sterilization of the circulating envelope in the form of a patent, a transverse view of the playing film (2) with a plastic coating of such a device <3, 5) is provided by the inner part. f örseglingeekikt (6), eoiti f öreträdeavie är en pro * penkopolymer. 6. Stere1iaeringepäee enligt n & got av de föregäende pat-tentkraven, kännetecknad av att mängekiktefilmen av plaet förutom nämnda ekikt deeeutom innehäller ett mellanekikt (4) mellan det värmebeatändiga thermoplaetskiktet C3) och det ekekt (4) företrädeevie är polypropen. 7. Steri1ieeringepäee enligt nägot av de föregäende pat-tentkraven, kännetecknad av att det yttereta ekiktet <3> av dees mängekiktefilm (2) av plaet utgöre av biaxiellt orienterat polyethylereereftaiat, det sees yttereta ekiktet <4> utke (5) the use of bleaching and elastomers of polypropylene or propylene copolymers, and of the inner two. föreeglingeekiktet <6> är polypropen eller en propenkopolymer. Θ. Sterilization of the filter is provided by the use of a patented device, which can be seen from 8 to 16 [mu] m, with a total of about 12 [mu] m, with a total of about 12 minutes (5/4). , 5.6) is 30-60 [mu] m, for about 40 [mu] m. i2 80636 9. A sterilizing method according to claim 8, which comprises more than <5) of the same type of method (4, 5, 6). 10. A sterilizing head comprising an active pharmaceutical composition comprising a kraft paper (1) comprising a kraft paper, which utilizes and comprises a genomic bacterium.