Injection-moulded disposable plastic item, production and use thereof
Patent Information
- Application Number
- EP2023769120
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-09-06
- Publication Date
- 2025-11-26
Smart Images
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Abstract
Description
[0001] Injection-molded single-use plastic articles, their manufacture and use
[0002] Technical field of the invention
[0003] The invention relates to an injection-molded disposable plastic article, a method for its production and its use.
[0004] Background to the invention
[0005] It is well known that plastic articles have the disadvantage that, when they come into contact with liquid media, especially liquid samples, components can leach out of the plastic material, thus contaminating the liquid medium or sample. These include, for example, plastic additives contained in the plastic that support thermal processing, such as antioxidants. These leachable components or contaminants, also called "leachables," then become part of the contents of the plastic article and falsify or contaminate it. This is particularly detrimental when tests are to be conducted on samples contained in the plastic articles, such as chemical or biological assays, where these contaminants can interfere with or even inhibit the tests. These contaminations are particularly serious, especially with small volumes.
[0006] Plastic articles are generally used in a wide variety of applications, for example in the field of life sciences, i.e. in fields or research areas that deal with living organisms, their structures and processes. These include, for example, the fields of medicine, pharmacology, biochemistry, biotechnology, in particular cell biology, microbiology or molecular biology. Plastic articles used in these fields are made from polyolefins, for example, which usually contain plastic additives or fragments that are then dissolved by the solvents commonly used in these fields, such as polar protic or aprotic solvents. This contaminates a liquid contained in the plastic article. The dissolution of plastic additives and / or fragments occurs because they are particularly soluble in polar protic or polar aprotic solvents.However, these solvents are typically used in the life sciences. Nonpolar solvents, which would dissolve nonpolar components from the plastic, such as oligomers, are practically never used in the life sciences. Therefore, there is a particular need for plastics in these applications that do not dissolve plastic additives and / or fragments from the plastic.
[0007] One way to prevent unwanted components from leaching out of the plastic is to omit the plastic additives. However, this often has the problem that the thermal stability of the plastic is reduced, making them impossible to process thermally and causing thermal decomposition. The thermal processability of plastics can be completely lost in the process.
[0008] Another way to prevent additives from leaching from the plastic is to apply one or more layers to the inside of a plastic article in which a liquid sample is to be stored and, for example, tested. These layers are, for example, SiOx layers, which are intended to act as a barrier against leaching from the plastic material. However, in most cases it has been found that the one or more SiOx layers on the plastics have insufficient barrier properties, and in some cases soluble components are even undesirably leached from the barrier layers themselves and migrate into the contained liquid sample. A further disadvantage of these layers is the risk that the coating can detach, for example during the treatment of a liquid sample, particularly when using ultrasound, and then contaminate the contained sample.
[0009] Furthermore, the manufacturing costs increase considerably due to the additional manufacturing step of coating the plastic article, which is very disadvantageous from an economic point of view.
[0010] For example, from the publication: Macromolecules, 2016, 49 (17), pp. 6497-6506, poly(cyclohexylethylene-ran-ethylene) copolymers (CE) have become known, whose statistical segment lengths were synthesized to correspond to those of isotactic poly(propylene) (iPP). These plastics do not appear to contain any additives. Films, but not containers, have been produced from these plastics. Therefore, there is great interest and a great demand for plastic articles that avoid the disadvantages of the prior art and, in particular, have no or virtually no components that can be released from the plastic, while the plastic is still thermally stable and processable in the usual way.
[0011] Detailed description of the invention
[0012] The above-described object is achieved according to the invention by an injection-molded disposable plastic article consisting of the two plastics low-density polyethylene (LDPE) and cyclic block copolymer (CBC), wherein 95 - 30 wt.% LDPE and 5 - 70 wt.% CBC are present, the injection-molded disposable plastic article is translucent or transparent, has a melt flow index MFR (190 °C / 2.16 kg) in the range of 0.1 to 2.5 g / 10 min according to ISO 1133 and contains no additives.
[0013] Preferred mixing ratios of low-density polyethylene (LDPE) to cyclic block copolymer (CBC) are in the range of 9:1 to 1:1.
[0014] For the sake of simplicity, low-density polyethylene is referred to as LDPE and cyclic block copolymer as CBC.
[0015] "Single-use article" refers to an article intended for single use only and then disposed of. The single-use article in this case is a single-use plastic article, meaning it is made of plastic. It should not contain any other components besides the two plastics.
[0016] The term "injection-molded disposable plastic article" refers to a disposable plastic article that is manufactured using an injection molding process and is only available through this process. Injection molding is a plastic forming process known to those skilled in the art, in which the plastic is liquefied in an injection molding device and injected under pressure into a mold, the injection molding tool. The liquefied plastic solidifies in the tool through cooling or a crosslinking reaction, with the tool's cavity determining the shape and structure of the molded part. After solidification, the tool is opened, and the molded part is removed. In the present invention, no crosslinking reaction takes place because no reactive groups, such as double bonds, are present in the two plastics.
[0017] In the following, the injection-molded disposable plastic article is also simply referred to as disposable plastic article or plastic article.
[0018] The first plastic contained in the single-use plastic item is selected from the class of LDPEs. In LDPE, "LD" stands for "low density" and "PE" for polyethylene. It is a low-density polyethylene, also known as low-density polyethylene (PE-LD). It is a thermoplastic. The polyethylene in LDPE is present in highly branched polymer chains, resulting in a low density in the range of 0.915 g / cm 3 up to 0.935 g / cm 3 (according to ISO 1183 or ASTM D1505, which are equivalent).
[0019] LDPE, or low-density polyethylene, is soft and has low heat resistance, but is very impact-resistant. The invention uses additive-free LDPEs. For example, commercially available LDPEs for medical and pharmaceutical use (medical-grade) are free of additives. LDPEs used are transparent or translucent and injection-moldable. An LDPE is injection-moldable if it has a melt flow index (MFR) according to ISO 1133 (MFR / 190 / 2.16: test temperature 190°C, mass 2.16 kg) in the range of 0.1 to 2.5 g / 10 min. Therefore, an LDPE with an MFR within the specified range is selected.
[0020] Exemplary commercial products for LDPE that can be used according to the invention are the products of the Borealis Group and the Sabic Group, such as Bormed™ LE6600-PH, a trademark of the Borealis Group, an additive-free LDPE with an MFR (190 °C / 2.16 kg) of 1.5 g / 10 min according to ISO 1133 or SABIC LDPE PCG09, an additive-free LDPE with an MFR (190 °C / 2.16 kg) of 7.5 dg / min (= 0.75 g / min) according to ISO 1133, or SABIC LDPE PCG22, an additive-free LDPE with an MFR (190 °C / 2.16 kg) of 22 dg / min (= 2.2 g / min) according to ISO 1133.
[0021] The second plastic contained in the disposable plastic item is selected from the class of cyclic block copolymers (CBCs) and is also a thermoplastic. This is a class of relatively new plastics from USI Corp., which are also available additive-free. Cyclic block copolymers (CBCs) are fully hydrogenated polymers based on styrene and conjugated dienes, obtained by anionic polymerization. The hydrogenation of styrene-butadiene block copolymers to CBCs is carried out, for example, according to the following schemes:
[0022] Styrene-butadiene block copolymers Cyclic block copolymers (CBC)
[0023] The residues RI, R2 and the parameters a, b, x, and y can be chosen appropriately. No information on this is available in the prior art.
[0024] The properties of the CBCs can be tailored over a wide range by adjusting the ratio of cyclohexylethylene (CHE) to ethylene-co-l-butene (EB) in the copolymer.
[0025] In general, CBC possesses high rigidity and significantly higher heat resistance than LDPE, but is brittle and difficult to process by injection molding. According to the invention, additive-free CBCs are used. For example, CBCs for medical and pharmaceutical use (medical-grade) that do not contain additives are commercially available. According to the invention, transparent and injection-moldable CBCs are used. A CBC is injection-moldable if it has a melt flow index (MFR) according to ISO 1133 (MFR / 190 / 2.16: test temperature 190°C, mass 2.16 kg) in the range of 0.1 to 2.5 g / 10 min. Therefore, a CBC with an MFR within the specified range is selected.
[0026] As examples of commercial products, the well-known types of CBC from USI Corporation, known under the trade names ViviOn™ Cyclic Block Copolymers (CBC), are mentioned. These include ViviOn™ CBC 8210, ViviOn™ CBC 8210XT, ViviOn™ CBC 1325, ViviOn™ CBC 1325EUT, ViviOn™ CBC 0510HSE, ViviOn™ CBC 0510, ViviOn™ CBC 0510HF, ViviOn™ CBC 0510T, ViviOn™ CBC 0510HT, ViviOn™ CBC 0510HFP, ViviOn™ CBC 0510HFE, and ViviOn™ CBC 0510FEP. The latest grade, ViviOn™ CBC 0510 HSE, is particularly impact-resistant and has particularly high flowability. These CBCs, for example, exhibit a transmittance (380-760 nm) according to ASTM D1003 of at least 91%. These CBCs all exhibit, for example, an MFR (260 °C / 2.16) in the range of 5 to 13 g / 10 min or an MFR (190 °C, 2.16) of 1 to 3 cm 3 / min (= 1 to 3 g / min) according to ASTM D1238 (which is equivalent to ISO 1133). Therefore, all of the specified CBCs are injection-moldable.
[0027] It has now been surprisingly discovered that the properties of LDPE and CBC can be combined to produce particularly advantageous properties for the plastic article made from them.
[0028] Due to its composition, the injection-molded disposable plastic article has the special feature that solvent-soluble components are reduced to an unavoidable level, i.e., to a minimum. "Reduced to a minimum" in this context means reduced to a minimal level or a minimum of solvent-soluble components that cannot be avoided. This applies in particular to polar protic or polar aprotic solvents. Polar aprotic solvents include, for example, ketones such as acetone, lactones, lactams, nitro compounds such as nitromethane, tertiary carboxylic acid compounds such as dimethylformamide, ureas, sulfoxides such as dimethyl sulfoxide, sulfones, and carbonic acid esters such as ethylene carbonate.Polar protic solvents include water, short-chain alcohols such as methanol and ethanol, primary and secondary amines, primary and secondary amides, carboxylic acids, and mineral acids. Therefore, subsequent sealing and / or coating of the surface of the plastic articles is generally not necessary.
[0029] The term "except for an unavoidable portion" of dissolved components means that components will always be dissolved from a plastic; this cannot be completely prevented. However, the proportion of dissolved components from the plastic is so small that it is usually below the detection limit and can be neglected. Contamination of the liquid contents of the disposable plastic article has not been observed to date. In other words, the injection-molded disposable plastic article can also be used in areas where very high quality requirements apply to the plastic, such as the life sciences sector, without the contents being contaminated by dissolved plastic components.
[0030] The plastic article is also inert to solvents, especially polar protic or polar aprotic solvents. The term "solvent inert" here means that the plastic article remains unchanged even after prolonged contact with a solvent or a mixture of solvents, meaning its chemical composition is not altered. Furthermore, as already explained, virtually no component is dissolved from the plastic article by the solvent(s).
[0031] Furthermore, the disposable plastic item is translucent or even transparent due to the plastics used. "Translucency" here means that there is partial light transmission, so that the plastic item, similar to frosted glass, is translucent but not transparent. The plastic item is then only partially translucent and not transparent, but translucent, which can also be described as opaque.
[0032] "Transparency" means that the plastic article is see-through. The term "transparent" refers to materials that transmit the majority of light, although a small portion is usually absorbed and scattered. Transparency is therefore the ability of a material to transmit light waves (transmission). Transparent materials are characterized by high transmittances. The term "transparent" here means that the disposable plastic article has a high light transmission of at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95% of the light at the wavelength used and for the thickness of the material used. For example, the opacity and light transmission of transparent plastics at 380 to 760 nm is determined according to ASTM D1003, yielding the values given above.
[0033] In the injection-molded disposable plastic article according to the invention, transparency is achieved only because no phase boundaries occur in the mixing ratios of the two components, low-density polyethylene (LDPE) and cyclic block copolymer (CBC). The two plastics exhibit particularly good miscibility. Phase boundaries when mixing different materials would lead to difficulties and visually impair transparency, as well as create mechanical weaknesses. Surprisingly, this is not the case with the disposable plastic article according to the invention.
[0034] Both transparent and translucent plastic items are particularly advantageous because the contents of the plastic item can be seen from the outside. This is useful, for example, when examining samples inside the plastic item.
[0035] Whether a single-use plastic article is transparent or translucent depends on the chosen mixing ratio of the two components used, low-density polyethylene (LDPE) and cyclic block copolymer (CBC): LDPE itself is generally translucent. CBC itself is transparent or even highly transparent. Surprisingly, the transparency or translucency is not lost in the single-use articles, so the optical properties of LDPE and CBC can be combined, allowing the contents of the plastic article to be viewed from the outside or even explicitly seen. The more CBC the single-use plastic article contains, the more the resulting plastic article transitions from translucent to transparent.
[0036] By mixing the two plastics, the injection-molded disposable plastic article acquires improved overall injection-molding properties, allowing the production of disposable plastic articles by injection molding. The disposable plastic article exhibits a melt flow index (MFR) (190°C / 2.16 kg) in the range of 0.1 to 2.5 g / 10 min according to ISO 1133 or ASTM D1238. ISO 1133 and ASTM D1238 are considered technically equivalent, so the resulting MFR values are the same. The flow behavior of a thermoplastic and thus its degree of polymerization can be determined using the melt flow index (MFR). This therefore explains the good injection-molding behavior of the plastic article of the invention.
[0037] The selected CBC / LDPE blends are therefore suitable for the production of single-use plastic items that can be manufactured, for example, in a single production step. These single-use plastic items can therefore be produced cost-effectively.
[0038] The shapes of the disposable plastic articles are not further restricted; they can be any shape known to the person skilled in the art. These include, for example, container caps, container closures, packaging, in particular in the form of containers, microtest plates (deepwell plates), containers, in particular sample containers such as bottles or vials, phials, sample tubes, cuvettes (i.e., sample containers with plane-parallel side surfaces) for optical examinations (e.g., UV / VIS) of liquids, containers with closures, in particular where the closure and the container are inseparably connected to one another, i.e., formed as one piece, pipette tips, syringes, or infusion containers.
[0039] However, the single-use plastic item should not be in the form of a film.
[0040] Depending on the shape of the disposable items, they have different requirements and property profiles. For example, the requirements for a pipette tip would be that it is straight and not warped, whereas for a container, stability, for example, during centrifugation, plays a role. These requirements and properties can be easily met with the invention.
[0041] By adjusting the ratio of the two plastics, it is possible to specifically adjust the thermal and mechanical properties of the plastic article of the invention and even to adapt or "tune" it for specific property profiles. While LPDE is not as thermally stable and very soft, thus having very limited usability when used alone, CBC is very stiff, but would sometimes be too stiff or too brittle as a sole component. The combination of both plastics therefore has the great advantage of providing a variety of property profiles that can be specifically tailored to specific requirements and applications. Furthermore, the disposable plastic article is unexpectedly translucent to transparent and additive-free.
[0042] The term "additive-free" means that the plastic article does not contain any additives in the form of additives of any kind that were added for or during production and that the plastics used as starting materials in the form of LDPE and CBC are also used without additives.
[0043] The possible uses for the disposable article are also not further limited; any use conceived by a person skilled in the art for a plastic article is possible. The intended use is therefore quite diverse and can include, for example, storage, sampling, sample processing, in particular conducting tests with samples, and the like.
[0044] Containers with very low sample concentrations are particularly advantageous, as the advantageous properties of the present invention are then particularly effective. For example, a pipette tip made of disposable plastic is particularly advantageous because the plastic prevents contamination of the contained sample by dissolved components (except for unavoidable minimum amounts).
[0045] These disposable plastic items are primarily used in fields that deal with living organisms, their structures, and processes, particularly in all steps performed in the laboratory. These include, for example, the fields of medicine, pharmacology, biochemistry, biotechnology, especially cell biology, microbiology, or molecular biology. Particularly preferred uses are in the storage of pharmaceuticals, cell cultivation, the conduct of biological or medical tests, and all process steps in a molecular biology laboratory, such as the handling, replication, and storage of biomolecules such as DNA, RNA, or proteins.
[0046] Furthermore, the present invention relates to a method for producing an injection-molded disposable plastic article according to the invention, comprising the steps of: dry mixing the granules of low-density polyethylene (LDPE) and cyclic block copolymer (CBC), which are each used additive-free, wherein a low-density polyethylene (LDPE) is used which is translucent or transparent and has a melt flow index MFR (190 °C / 2.16 kg) in the range of 0.1 to 2.5 g / 10 min according to ISO 1133 and a cyclic block copolymer (CBC) is used which is transparent and has a melt flow index MFR (190 °C / 2.16 kg) in the range of 0.1 to 2.5 g / 10 min according to ISO 1133 and
[0047] 95 - 30 wt.% low-density polyethylene (LDPE) and 5 - 70 wt.% cyclic block copolymer (CBC) are used, and no plastic additive is added and
[0048] The resulting mixture is then injection-molded to produce a disposable plastic article in the desired shape. The manufacturing process is essentially a dry-blend process. Only the granules are mechanically mixed together, followed by injection molding. It is preferable to avoid extrusion prior to injection molding.
[0049] A particularly advantageous aspect of the process is that it is fundamentally possible to use injection molds typically used for injection molding polypropylene directly to produce the corresponding plastic articles according to the invention. This represents a significant simplification of the process and is particularly cost-effective.
[0050] The invention also relates to the use of the injection-molded disposable plastic article according to the invention in medicine, pharmacology, biochemistry, biotechnology, in particular cell biology, microbiology or molecular biology, for storage, sampling, sample processing, carrying out tests, in particular of liquid-containing ingredient(s), preferably in the presence of polar protic or polar aprotic solvents.
[0051] The term "ingredient(s)" means any form of one or more ingredients that are contained in the injection-molded disposable plastic article according to the invention, for example, that are to be stored therein and, if necessary, further processed. For example, a sample container containing a sample.
[0052] The term "liquid ingredient(s)" means that the ingredient(s) are at least partially present with a liquid or a mixture of liquids in the injection-molded disposable plastic article according to the invention. Any combination of ingredient(s) and liquid(s) is conceivable. This may, for example, be a solution, suspension, emulsion, or dispersion.
[0053] The advantages of the invention are extremely complex:
[0054] Two plastic classes are used: low-density polyethylene (LDPE) and cyclic block copolymer (CBC), which do not contain any additives, from which a single-use plastic item is manufactured by injection molding. Production can therefore be carried out simply, with the option of using injection molds used for polypropylene injection molding. This is particularly advantageous because no separate injection molds need to be created.
[0055] The single-use plastic item is translucent or transparent, which is advantageous because the ingredient(s) are visible. This can be important, for example, for viewing or checking the ingredients, for example, as part of quality control, or for sampling and sample analysis, for example, when conducting tests that use an optical method.
[0056] The disposable plastic article has a melt flow index (MFR) (190 °C / 2.16 kg) in the range of 0.1 to 2.5 g / 10 min according to ISO 1133, making it particularly suitable and easy to produce by injection molding. Blending the two plastics improves the overall injection molding properties of the disposable plastic article. The selected CBC / LDPE blends are therefore suitable for the production of disposable plastic articles in a single production step. The disposable plastic articles can therefore be manufactured cost-effectively.
[0057] There are also no additives in the single-use plastic item.
[0058] Preferred mixing ratios of low-density polyethylene (LDPE) to cyclic block copolymer (CBC) range from 9:1 to 1:1. The two plastics exhibit unexpectedly good miscibility, with no phase boundaries observed during mixing. By adjusting the mixing ratio, different requirements and property profiles for disposable plastic items can be specifically tailored.
[0059] The injection-molded disposable plastic article also has the particularly advantageous property that components that can be dissolved out by solvents are reduced to a minimum, except for an unavoidable proportion. This is particularly true when using polar protic or polar aprotic solvents. Furthermore, it is possible to subject the disposable plastic article to a hydrogen plasma treatment. This not only sterilizes but also chemically functionalizes the plastic surface. This gives the disposable plastic article molecule-repellent, particularly biomolecule-repellent, properties, preventing nonspecific adsorption of liquid ingredients on the walls of the disposable plastic article that are in contact with the liquid ingredients. The ingredients thus remain largely unchanged upon contact with the disposable plastic article.
[0060] The shape of the disposable plastic item is not further restricted if it is manufactured by injection molding, so that a variety of shapes for a wide range of uses are possible.
[0061] Examples of implementation:
[0062] Examples 1 to 6:
[0063] An injection molding method for producing the injection-molded disposable plastic article according to an embodiment of the invention is explained in detail below:
[0064] The plastics used were Bormed™ LE6600-PH, a low-density polyethylene (LDPE) from the Borealis Group, and ViviOn™ CBC 0510HFE, a cyclic block copolymer (CBC) from USI Corp.
[0065] A two-cavity full hot runner mold was used as the injection molding tool. The plastics were used as granules in the following mixtures:
[0066] Table 1:
[0067] The injection molding parameters were as follows:
[0068] Screw diameter: 20 cm
[0069] Mass temperature: 235 - 260 °C
[0070] Tool temperature 30 °C
[0071] Cooling time: 4 s
[0072] Injection pressure: about 1000 bar
[0073] Cycle time: 8 s
[0074] The injection pressure increased with the addition of ViviOn™ CBC 0510HFE, for example, by
[0075] 150 bar at a share of 50%.
[0076] After cooling, the mold was opened, and the injection-molded disposable plastic article could be removed. In the example cases, these were containers. These were translucent in Examples 1 and 2 and transparent in Examples 3 to 6. The melt flow index (MFR) (190°C / 2.16 kg) for the injection-molded disposable plastic articles of Examples 1 to 6 ranged from 0.1 to 2.5 g / 10 min according to ISO 1133.
[0077] Example 7:
[0078] Centrifugation test:
[0079] Using the plastic compositions listed in Table 1, disposable plastic articles in the form of centrifuge tubes with lids and a capacity of 1.5 mL were produced using the injection molding process described in Examples 1 to 6. The lid was firmly attached to the centrifuge tube with a ribbon, resulting in a one-piece disposable plastic article.
[0080] A saturated NaCl solution was added to the centrifuge tubes, the lids were closed, and the centrifuge tubes were tested in an Eppendorf C5430 Research centrifuge at 4°C and 25°C for 90 minutes. The maximum centrifugability was:
[0081] 25000 g at 4°C
[0082] 20000 g at 25°C.
[0083] The centrifugation tubes can therefore also be used at high g-values.
[0084] The centrifugation test therefore confirms that the single-use plastic items can tolerate the load under high g-values and show no adverse effects on the material.
[0085] Example 8:
[0086] Vapor tightness test:
[0087] Using the plastic compositions of Examples 3, 4, and 6 listed in Table 1, disposable plastic articles in the form of centrifuge tubes with lids with a capacity of 1.5 mL were manufactured using an injection molding process as described in Examples 1 to 6. These tubes were filled into six ethanol / water (1:1) containers, sealed with the lid, and then stored at 70 °C for 1 hour. The containers were weighed at the beginning and end of the test. A container is considered vapor-tight and in accordance with the specification ("in spec") if the difference between them is less than 0.2%.
[0088] The results of the vapor tightness test were as follows:
[0089] Table 2:
[0090] The results show that 6 identical containers were always tested, 5 of which were within specification, i.e. leak-proof.
Claims
Claims 1. Injection-molded disposable plastic article consisting of the two plastics low-density polyethylene (LDPE) and cyclic block copolymer (CBC), with 95 - 30 wt.% LDPE and 5 - 70 wt.% CBC being present, the injection-molded disposable plastic article being translucent or transparent, having a melt flow index MFR (190 °C / 2.16 kg) in the range of 0.1 to 2.5 g / 10 min according to ISO 1133 and containing no additives.
2. Injection-molded disposable plastic article according to claim 2, characterized in that the mixing ratio of low-density polyethylene (LDPE) to cyclic block copolymer (CBC) is in the range of 9:1 to 1:
1.
3. Injection-molded disposable plastic article according to claim 1 or 2, characterized in that in the disposable plastic article, components which can be dissolved out by solvents are reduced to a minimum except for unavoidable proportions.
4. Injection-molded disposable plastic article according to claim 3, characterized in that the solvent(s) is / are a polar protic or polar aprotic solvent or a mixture thereof.
5. Injection-molded disposable plastic article according to claim 4, characterized in that the polar aprotic solvent is selected from ketones such as acetone, lactones, lactams, nitro compounds such as nitromethane, tertiary carboxylic acid compounds such as dimethylformamide, ureas, sulfoxides such as dimethyl sulfoxide, sulfones or carbonic acid esters such as ethylene carbonate, or mixtures thereof and the polar protic solvent is selected from water, short-chain alcohols such as methanol and ethanol, primary and secondary amines, primary and secondary amides, carboxylic acids, mineral acids and mixtures thereof.
6. Injection-molded disposable plastic article according to one of claims 1 to 5, characterized in that this is in the form of a cap of a container, a closure of a container, a packaging, in particular in the form of a container, a micro test plate, a container for liquids, in particular sample containers, such as a bottle or a vial, a phial, a sample tube, a cuvette for optical examination of liquids, a container with a closure, in particular wherein the closure and the container are inseparably connected to one another, a pipette tip, a syringe or an infusion container.
7. A method for producing an injection-molded disposable plastic article according to one of claims 1 to 6, comprising the steps of: dry mixing the granules of low-density polyethylene (LDPE) and cyclic block copolymer (CBC), each of which is used without additives, wherein a low-density polyethylene (LDPE) is used which is translucent or transparent and has a melt flow index MFR (190°C / 2.16 kg) in the range of 0.1 to 2.5 g / 10 min according to ISO 1133, and a cyclic block copolymer (CBC) is used which is transparent and has a melt flow index MFR (190°C / 2.16 kg) in the range of 0.1 to 2.5 g / 10 min according to ISO 1133, and 95 -30 wt.% low-density polyethylene (LDPE) and 5 - 70 wt.% cyclic block copolymer (CBC) are used, and no plastic additive is added and Injection molding of the resulting mixture to obtain an injection molded disposable plastic article in the desired shape.
8. Method according to claim 7, characterized in that Injection molds used for injection molding of polypropylene.
9. Use of the injection-molded disposable plastic article according to one of claims 1 to 6 in medicine, pharmacology, biochemistry, biotechnology, in particular cell biology, microbiology or molecular biology, for storage, sampling, sample processing, carrying out tests, in particular of liquid-containing ingredients, preferably in the presence of polar protic or polar aprotic solvents.