The Common Problems In Material Selection And Design Of Medical Sterilization Pouches And Plastic Packaging
Returns List Reffer：kmnadmin Click number： Release time：2022-12-13 11:25:23
Medical sterilization paper plastic packaging bag is a kind of disposable medical sterilization packaging materials, with good air permeability, conducive to sterilization media penetration, high resistance to bacteria after sterilization, sterilization process chemical monitoring is convenient, simple packaging sealing, good perspective, long safety period after sterilization, easy to open and other advantages, but also can greatly reduce the cost of procurement and waste recycling convenience, In line with the requirements of environmental protection, is the best comprehensive performance of a medical sterilization packaging material.
However, some problems are often encountered in the actual production of medical sterilized plastic packaging bags. In this paper, the paper mainly discusses the material selection and design of sterilization paper plastic packaging common problems, and how to solve them.
1, the correct selection of materials, is the first step of medical sterilization packaging manufacturing
According to the sterilized packaging requirements of EN868-5, ISO11607-1:2006, GB/ T19633-2005 and YY/T0698-2009, medical sterilized packaging materials must meet the following basic requirements:
• Compatibility with sterilized devices
The nature and intended use of the device determine the sterilization method to a certain extent, and the different sterilization methods affect the material selection of the packaging system.
Such as: strong adsorption articles, not suitable for ethylene oxide sterilization; Equipment with PE parts are not high temperature resistant, not suitable for high pressure steam sterilization; For expensive instruments, sterilization with short sterilization cycle is generally selected as far as possible to improve the frequency of use. Therefore, the nature of the device itself to a certain extent also determines the packaging system adopted.
• Appropriate to the sterilization method used
The properties of packaging materials subjected to the specified sterilization methods shall be within the specified limits.
For example: ethylene oxide sterilization, the packaging system requires that at least one of the materials has air permeability, to ensure that ethylene oxide can enter the sterilization, and can be resolved after sterilization.
Irradiation (gamma ray) sterilization, which does not have high requirements for paper, but has a great impact on polymer materials, requires that all packaging materials constitute the packaging system, can resist the treatment of radiation without aging and cracking.
High-temperature steam sterilization requires that all materials that make up the packaging system be able to withstand the appropriate heat, typically at 121 ˚C to 134˚C for 15 to 30 minutes.
Low temperature formaldehyde sterilization requirements for materials are basically equal to steam sterilization, but the penetration capacity of formaldehyde gas is relatively poor.
Plasma sterilization requires that packaging materials constituting the packaging system should not contain biological fibers, because these materials can rapidly interact with oxidant and superoxide free radicals, resulting in insufficient concentration of sterilizing agent and resulting in sterilization failure.
• Adequate penetration
Packaging materials should be conducive to the entry and exit of sterilization factors to ensure sterilization effect.
• Barrier properties of microorganisms
Microbial barrier is the ability of the packaging system to prevent the entry of microorganisms under specified conditions.
• Mechanical properties
The packing material should be strong enough to prevent damage during sterilization. These include the tensile strength, puncture strength, tearing strength and breaking strength of the material.
• Non-toxic
The material itself does not contain any potentially risky ingredients, including the surface coating ingredients of some packaging materials. The material is stable under conventional and designated sterilization environment, and does not decompose, split or transfer potentially harmful substances to the surface of the packaging equipment.
• Allow the packaging to be opened sterile
There are high requirements on the materials and the thermal bonding between different materials. When the package is opened, there should be no fiber debris generated.
Medical sterilization paper plastic packaging bag is a part of medical sterilization pouches, the selection of materials to meet the above requirements, there are some other requirements. For example, the paper of the medical sterilization paper plastic bag should not be decolorized, the PH value of the paper extract should be greater than or equal to 5 and less than or equal to 8, the fluorescence brightness should not be greater than 1%, the UV irradiation source in the distance of 25cm, the number of fluorescent spots of each 0.01 square meter axis of 1mm is not more than 5, The hydrophobicity of paper means that the penetration time should not be less than 20 seconds, the average aperture of paper should not exceed 35 microns, and the maximum value should be less than 50 microns, and the air permeability and water absorption of paper also have certain requirements, but also need to meet the requirements of paper printing.
In addition, in the selection of medical sterilization paper plastic packaging bags, also need to fully consider the operability of materials. For example, PP film and PE film are very commonly used plastic films. Although these plastic films also meet the requirements of medical packaging materials, they are rarely used directly in medical paper and plastic bags. Because they are not easy to make bags, most of them are used after PP film or PE film and other materials are composite or co-extruded.
Correct material selection, to the perfect sterilization of the production of plastic packaging bags, laid a solid foundation.
2. Product design is also an important link that cannot be ignored
A qualified medical sterilile packaging is inseparable from reasonable design. From the packaging style to the production and processing, all need to be fully considered.
In the design of packaging, as far as possible to take into account the characteristics of the product itself and demand: to avoid the light of the product, can not use paper plastic packaging, should use aluminum foil composite bag or paper aluminum composite bag; The products with a certain thickness are packed in paper and plastic bags, so it is more beautiful and reliable not to use the mid-seam breathable bag. And need to breathe large amount of products, as far as possible with plastic or paper bag packaging; Need to moisturize or have liquid products, it is necessary to use good barrier material to do its packaging and so on.
Here are a few often overlooked issues that I hope will draw the attention of the industry:
(1) The design of peeling open paper plastic bag
For the paper plastic bags on the market at present, in order to facilitate the opening of the paper plastic bag, the opening end of the paper plastic bag is peeled off. The dislocation between the plastic film and the dialysis paper is generally no less than 1mm, and the semicircle incision is not adopted as far as possible. Because the semicircle incision is too small and shallow, it is inconvenient to operate the thumb and lose the real meaning of the incision. Cutting too big and deep, although convenient to separate the plastic film and dialysis paper, but waste the effective area, or separated after the pinch is too small.
The ideal design for peeling and opening is to cut off a rectangular notch about 3~4mm wide from the paper at the opening, in addition to the dislocation at the opening of the two layers of material, which is convenient for the separation of plastic film and dialysis paper, and convenient for the hands to pinch after separation, and the overall use area is not wasted.
In addition, a large part of medical plastic packaging bags, in order to easily open, open the edge of the choice of V-type sealing hot. This is convenient to open, but in sterilization, especially in the case of steam sterilization, it is easy to appear the V-shaped explosion phenomenon. In order to solve this phenomenon, a reinforcing bar is added in the inner concave of the V type, which can better meet the needs of steam sterilization.
(2) Anti-scraps design of paper and plastic packaging
When the paper plastic bag is peeled open, it is easy to have the phenomenon of confetti. When this happens, most bag operators will think it is the cause of improper operation or materials. Of course, there are also some reasons for the nature of the material, such as the uniform situation of gluing paper gluing is not good, the adhesive strength of the glue itself is unreasonable; There is also the operation error caused by peeling strength is too large, and the stripping when the phenomenon of confetti. But a large part of the reason is due to the negligence of the design, did not really understand the nature of the paper plastic in the ironing of the bag, resulting in the stripping and opening of the paper scraps.
In the process of making bags, most of them go through the steps of hot pressing, cooling and cutting molding of the moulds with fixed shapes.
Whether the plastic film surface or dialysis paper surface is heated on one side or both sides at the same time, the ironing principle of plastic film and dialysis paper is as follows: The thermal bonding layer of the plastic film surface is melted, combined with the dialysis paper coating layer or treatment surface, or not treated surface, and then through the pressing of a certain pressure of the hot stamping mold, as well as cooling and solidification of the cooling device, the dialysis paper and the plastic film have a certain peeling strength.
In the process of hot pressing for the production of paper-plastic packaging bags, when the hot stamping die is sealed, the die forms a force with the platform below and the silicone pad. The silicone pad can make all the hot parts (hot seams) as evenly hot as possible. But the pressure of each edge of the mold is larger than that of other places. In order to meet the peeling strength of the whole hot seam in a certain range, the peeling strength of the most edge part will be larger than that of the other parts, so that when peeling and tearing, it is easy to produce confetti phenomenon. It is relatively simple to solve this phenomenon that the most edge peeling strength is large and the confetti is produced. It only needs to be polished into a certain arc shape of all the edges and corners of the contact surface of the hot mold and paper and plastic.
There is also a situation, easy to produce peel open when confetti, is also one of the most easily overlooked. In cutting forming, whether it is transverse or longitudinal ironing bag making, cutting knife or round knife rolling to remove the residual material on the edge of the bag, the position of cutting knife and round knife cutting is the key. Previously, we have said that the hot sealing between the paper and the film is based on the melting of the heat sealing layer of the film, and part of it penetrates into the hot sealing surface of the dialysis paper, thus forming the peeling strength between the plastic film and the dialysis paper. When our cutter cuts off plastic film and dialysis paper, the principle of cutting is similar to that of scissors. If the blade of the cutter is not sharp enough, there will be an interlocking situation between the plastic film and dialysis paper at the cutting place. If the cutter is cut off at the ironing place between the plastic film and dialysis paper, the interlocking situation will be more serious.
On the one hand, when the dialysis paper is cut off, the fibers on the end face of the cut off are destroyed. The plastic film is no longer separated from the fibers on the surface of the dialysis paper, but from the fibers on the end face of the dialysis paper, so it is easy to produce paper scraps. On the other hand, because the peeling strength of the incision edge is actually the sum of the strength of the plastic film and dialysis paper when ironing, and the strength of the plastic film and dialysis paper when cutting off, it is easy to appear the phenomenon of paper debris when peeling.
In order to avoid the stripping of paper scraps brought by this situation, it should be considered in the design. The transverse bag pressing die is slightly narrower than the actual bag. After the bag is sealed and pressed, there should be a gap between the first bag and the second bag pressing die. There is also a gap outside the edge of the two ironing seams when the longitudinal bag-making is done
That is, when the cutter cuts off, it should not be cut on the hot seam (the hot joint of plastic film and dialysis paper) as far as possible, but cut outside the hot seam. In order to achieve this requirement, there are printed packaging bags, we must take this into account in the design.
(3) Design of adhesive tape sealing and folding position of medical Ziplock bag
Medical sterilization of plastic packaging bags, there are some medical ziplock bags. Medical ziplock bag is also called medical self seal sterilization pouches, self-adhesive flat pocket or self-adhesive flat pocket.
The self seal sterilization pouches is the release paper with the double-sided tape removed from the mouth of the bag. After folding, half of the width of the double-sided tape is affixed to the plastic film, and the other half is affixed to the dialysis paper. In order to meet this requirement, the position and form of folding line have undergone several improvements.
At first, the upper fold line is printed at the fold position, and when folded, the fold is folded along the printed fold line. However, it is easy to shift and deflect when folding. For better positioning and convenient folding, cut the dotted line of the dialysis paper at the folding place.
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