Dispensing device comprising polyester composition

Abstract

The invention relates to a dispensing device intended to be mounted on a container to form a dispenser for a fluid product, said dispensing device comprising a polyester composition consisting essentially of a mixture of component A and component B defined as follows: A: a copolyether ester elastomer (COPE); a hard segment consisting essentially of a polyester and a soft segment of an aliphatic polyether and having a hardness of less than 50 Shore D; and B: polyethylene terephthalate (PET) or copolyester, or a mixture of both.

Description

Technical Field

[0001] The present invention uses a polyester composition based on polyethylene terephthalate (PET) or the like instead of polyolefins (polyethylene (PE) or polypropylene (PP)) for manufacturing dispensing devices for the packaging industry, which are intended to be mounted on bottles, tubes and cans for the packaging industry. The advantageous fields of use are the food, cleaning products, personal care, pharmaceutical and cosmetic fields. Background Art

[0002] The circular economy for plastic packaging gives rise to the need to design mono-material packaging systems, i.e., in order to optimize their recycling, in which the different components are made of compatible polymer materials or materials from the same chemical family. So far, most stoppers and dispensing devices intended for PET containers (such as bottles, tubes or cans) on the market are made of multi-material components or mono-material components based on polyolefins (such as polyethylene or polypropylene). As far as we know, so far, a mono-material dispensing device based on polyester for PET containers has not been described in the literature.

[0003] ● Description of PET

[0004] Polyethylene terephthalate or PET is a semi-crystalline thermoplastic polyester obtained by the polycondensation of two monomers (terephthalic acid and ethylene glycol), as shown in the following formula 1. Its main properties are impermeability to gases and liquids, chemical resistance, rigidity and transparency.

[0005]

[0006] PET is commonly used in various application fields: packaging (bottles for water and carbonated beverages, fruit trays, bottles for cosmetics, etc.), automotive (door handles, interior trim elements, air vents), electronic devices (sockets, lamp holders, fuse boxes). In addition to the properties mentioned above, PET is currently the most recycled plastic, and thus a good candidate for the circular economy.

[0007] ● Comparison with Other Polymers

[0008] The following Table 1 compares the properties of PET with other polymers (such as polypropylene or polyethylene and ABS).

[0009] Table 1: Comparison of the mechanical properties of plastic types used in the packaging industry

[0010]

[0011] Compared with polyolefins (PP or PE), PET has the following advantages:

[0012] - Gas barrier properties

[0013] - Good chemical resistance and heat resistance

[0014] In addition to the advantages mentioned above, it also has other advantages and some disadvantages summarized in Table 2 below:

[0015] Table 2: Advantages and limitations of PET compared to PP (Advantages and disadvantages of PET compared to PP)

[0016]

[0017] Despite its beneficial properties and positive effects in the circular economy, it is clear that pure PET cannot be used as a substitute for polyolefins, as shown in Table 1.

[0018] The object of the present invention is to provide new thermoplastic compositions which are mainly intended for, but not limited to, injection molding, and which have a lower hardness, a lower tensile modulus, a higher impact strength and a lower melt viscosity compared to pure PET, and wherein these properties are similar to those of PP while maintaining the ability to recycle PET obtained from conventional PET recycle streams. Another object of the present invention is to provide a plate of a polyester material formulation from which materials can be selected, the properties of which can be adapted to the needs of designing and manufacturing components of a dispensing device for the packaging industry, said dispensing device being particularly intended for use on containers dispensed by the packaging industry and which can be produced based on PET or copolyesters. Summary of the Invention

[0019] To achieve these objects, the present invention proposes a dispensing device intended to be mounted on a container to form a dispenser for a fluid product, said dispensing device consisting essentially of a polyester composition which consists essentially of a mixture of component A and component B as defined below:

[0020] A: A copolyetherester elastomer (COPE), said copolyetherester elastomer consisting essentially of a hard segment of polyester and a soft segment of aliphatic polyether and having a hardness of less than 50 Shore D, and

[0021] B: Polyethylene terephthalate (PET) or a copolyester, or a mixture of both.

[0022] Thus, the present invention defines a dispensing device, such as a stopper, an applicator, or more generally, an integral dispensing device, which is intended to be mounted on or associated with a polyester container to form a dispenser for a fluid product, said dispensing device consisting essentially of the polyester composition defined above, said polyester composition consisting essentially of A and B.

[0023] Herein, a fluid product is defined as any substance that can flow and thus includes products in liquid form, as well as powdery or granular solids.

[0024] The present invention also provides a dispensing device intended to be mounted on a container to form a dispenser for a fluid product, said dispensing device being free of polyolefins and comprising a plurality of elements, at least one element consisting essentially of a polyester composition which consists essentially of a mixture of component A and component B as defined below:

[0025] A: a copolyetherester elastomer (COPE), said copolyetherester elastomer consisting essentially of a hard segment of polyester and a soft segment of aliphatic polyether and having a hardness of less than 50 Shore D, and

[0026] B: polyethylene terephthalate (PET) or copolyester, or a mixture of both, and all other elements are made of component A or component B.

[0027] Thus, the present invention defines a multi-element dispensing device (such as a pump or a valve) intended to be mounted on or associated with a polyester container to form a dispenser for a fluid product, said dispensing device being free of polyolefins, at least one element consisting essentially of the polyester composition defined above, said polyester composition consisting essentially of A and B, and all other elements being made of component A or component B.

[0028] The presence of functional additives is not excluded in the polyester composition, which in all cases still consists essentially of A and B.

[0029] Advantageously, the copolyester is obtained by polymerizing at least one acid selected from terephthalic acid, 2,5-furandicarboxylic acid or isophthalic acid with an alcohol selected from ethylene glycol, cyclohexanedimethanol, propylene glycol and isosorbide, or by recycling a polymer composed of these monomers.

[0030] The copolyester may be glycol-modified polyethylene terephthalate (PETG).

[0031] The copolyester may also be selected from glycol-modified polycyclohexylene dimethylene terephthalate (PCTG), acid-modified polycyclohexylene dimethylene terephthalate (PCTA), polyethylene glycol-co-isosorbide terephthalate (PEIT) and polyethylene furandicarboxylate (PEF). Mixtures of various copolyesters from PETG, PCTG, PCTA, PEIT and PEF are conceivable. It is also conceivable to use raw materials "recycled" by mechanical or chemical means and corresponding to the characteristics mentioned above.

[0032] According to another feature of the present invention, component A is present in a weight ratio of 0.5% to 40%, advantageously 1% to 30%, and preferably 5% to 15%, and component B is present in a weight ratio of 60% to 99.5%, advantageously 70% to 99%, and preferably 85% to 95%.

[0033] According to another aspect of the present invention, the hard segments of the polyester in component A may be composed of butylene terephthalate units. It is also conceivable to replace butylene terephthalate with ethylene terephthalate without departing from the scope of the present invention.

[0034] Compared with a pure polyester matrix (such as PET) or compared with polypropylene, the composition obtained by adding an elastomer (COPE) to a polyester matrix (PET or the like) will have a lower tensile modulus, lower hardness, improved impact strength, and better melt viscosity, which will make it better suitable for implementation, especially by injection molding, but not limited thereto, and better suitable for the design of a dispensing system intended for a polyester container, which polyester container may also be derived from a recycling stream.

[0035] The present invention also defines a dispenser for a fluid product, comprising an integral or multi-component dispensing device as defined above.

[0036] Advantageously, the dispenser for a fluid product comprises a container made of component B, on which a dispensing device is mounted to dispense the fluid product contained in the container. Optionally, the container may be made of polyester or polyolefin. Optionally, it may also be made of glass, metal, ceramic, etc.

[0037] [Single figure] The single figure is a graph showing the shear-thinning behavior curves measured by a capillary rheometer at 275 °C for samples 1, 4, and 9 and at 205 °C for sample 2. Detailed description

[0038] The present invention relates to a polyester composition, which can be used in suitable plastic molding processes, such as for injection molding. Before using the polyester mixture in an injection press, in processes for injection blow molding, extrusion, extrusion blow molding, calendering, or thermoforming, or any manner suitable for transforming and processing polymers, preliminary mixing through a compounding or extrusion unit may or may not be carried out. Before any high-temperature treatment of the polyester material, suitable drying is preferably carried out at a rate of less than 0.05% by weight.

[0039] The main polyester matrix will be polyethylene terephthalate (PET) or a copolyester obtained by the polymerization of terephthalic acid, 2,5-furandicarboxylic acid or isophthalic acid with ethylene glycol, cyclohexanedimethanol, propylene glycol or isosorbide. Such copolyesters contain materials known to those skilled in the art, and their abbreviations are: PETG, PCTG, PCTA, PEIT, PEF, etc. Such polyesters can be used to manufacture containers, bottles, tubes and cans typically intended for the mass distribution and packaging industries. Such polyester matrices can also be derived from recycling streams, and their chemical composition always meets the above criteria.

[0040] An elastomer from one of the families described below will be mixed with the main polyester matrix in an amount of 0.5% to 40% by weight, advantageously 1% to 30%, and preferably 5% to 15%. Such an elastomer preferably has a Shore D hardness of less than 50 units and belongs to the polyester-ether elastomer (COPE) family, which is a thermoplastic copolyester elastomer, the structural building blocks of which are linked together by ester chemical bonds and are formed by two microstructural phases:

[0041] Rigid phase (ester-based rigid segment): A polymer in crystalline form that ensures the cohesion and strength of the material. The rigid phase of COPE is typically PBT (polybutylene terephthalate), but can also be the hard segment of PET (polyethylene terephthalate).

[0042] Flexible phase (ether-based flexible segment): A rubbery polymer that imparts elastic properties to the material, typically a polyether diol, such as but not limited to polytetramethylene ether glycol (PTMEG) or polyethylene glycol.

[0043] It should be noted that depending on the type of application and the desired properties, COPE can be replaced by one of the following three chemical families:

[0044] 1) Thermoplastic Polyurethane (TPU) Elastomer

[0045] TPU has a microstructure similar to COPE. They are materials in which the bonds between the structural blocks are urethane bonds and are formed by two microstructural phases:

[0046] Rigid phase (urethane-based rigid segment): A polymer in crystalline form that ensures the cohesion and strength of the material. The rigid phase of TPU is typically composed of methylene diisocyanate (MDI) or toluene diisocyanate (TDI) related to the chain extender diol molecule, but not only composed of methylene diisocyanate (MDI) or toluene diisocyanate (TDI) related to the chain extender diol molecule, and the chain extender diol molecule is typically butanediol (BDO), but not only butanediol (BDO).

[0047] Flexible phase (ether-based or polyester-based flexible segments): A rubbery polymer that imparts elastic properties to the material, which can be polyether diols (such as but not limited to PTMEG (polytetramethylene ether glycol)), or aliphatic polyester-based macrodiols (such as but not limited to polycaprolactone or polybutylene succinate (PBS)).

[0048] 2) Polyether Amide Elastomer (COPA)

[0049] COPA is a thermoplastic copoly elastomer in which the bond between the structural blocks is an amide bond and is formed by two microstructural phases:

[0050] Rigid phase (polyamide-based rigid segments): A crystalline form of polymer that ensures the cohesion and strength of the material. The rigid phase of COPA is usually polyamide 12, which is obtained, without limitation, by the polycondensation of aminolauric acid or the ring-opening of laurolactam.

[0051] Flexible phase (ether-based flexible segments): A rubbery polymer that imparts elastic properties to the material, which can be but not limited to polyether diols, such as PTMEG (polytetramethylene ether glycol).

[0052] 3) Diols, Also Known as Aliphatic Polyethers

[0053] Polyethylene glycol (PEG) or polytetrahydrofuran (PTMEG) are flexible molecules with the following chemical structures:

[0054] Examples of the chemical structure of a diol (in this case, polyethylene glycol)

[0055]

[0056] To minimize migration to the product contained in the dispenser, it is preferable to consider using the product in a mixture with an average molar mass of at least 4000 g / mol.

[0057] Examples

[0058] · Test Procedures

[0059] Embodiments : The raw material formulation is first mixed in the form of granules in a suitable proportion, and then dried at 120 °C for 6 h before any high-temperature conversion process. Then, for mechanical testing, the dried granule mixture is injection molded to form dumbbell-shaped samples, or for rheological testing, it is mixed and converted into granules by an extruder.

[0060] Density Measurement: According to the instructions of Method A of standard ISO 1183, the density is measured using a balance equipped with a wire density measurement kit.

[0061] Mechanical Tests: According to the standard ISO 527, A1 dumbbells were used to measure the tensile properties of different embodiments obtained with a tensile speed of 50 mm / min as presented below. The impact strength values were obtained according to the standard ISO 179. The hardness values were obtained according to the ISO 868 procedure.

[0062] Rheological Tests: The curves of the melt viscosity as a function of the shear rate were obtained using a capillary rheometer and measured at a temperature of 275 °C. Before measurement, all samples in particulate form were dried at 120 °C for 6 h.

[0063] · Results

[0064] Example 1: In this example, a control sample consisting of 100% PET (obtained by the polymerization of terephthalic acid and ethylene glycol, having an IV viscosity of 0.8 dL / g, which is considered "bottle grade" by the packaging industry) was dried at 120 °C for 6 h and then injection molded into an A1 dumbbell shape for mechanical testing. The dried granules of this material were also mixed through an extruder to obtain treated granules. This example was included in this document only for the purpose of comparison with the following examples. The curves of the mechanical properties and shear thinning behavior in the molten state can be found in Table 3 and the accompanying drawings below.

[0065] Example 2: In this example, a control sample consisting of 100% polypropylene copolymer (having a melt flow index considered to have "injection quality" and suitable for the injection molding of bottle caps and closures in the packaging industry) was injection molded into an A1 dumbbell-shaped sample for mechanical testing. The granules of this material were also mixed through an extruder to obtain conditioned granules. This example was included in this document only for the purpose of comparison with the following examples. The curves of the mechanical properties and shear thinning behavior in the molten state can be found in Table 3 and the accompanying drawings below. The mechanical properties and melt viscosity are very different from those of Example 1, illustrating the gap between the two materials that the present invention aims to overcome.

[0066] Examples 3 to 6: In these examples, a particulate mixture of PET having an IV viscosity of 0.8 dL / g (considered by those skilled in the art as "bottle grade") and COPE having a Shore D hardness of 25 at a ratio of 1% to 30% by weight (as shown in Table 3 below) was prepared. The particulate mixture was then dried at 120 °C for 6 h and then injection molded into A1 dumbbell-shaped samples for mechanical testing. The mixture of dried particles was also mixed through an extruder to obtain treated particles. The mechanical properties are shown in Table 3 below. Increasing the amount of COPE in the sample allows the mechanical properties of the material to be adjusted, and in the case of Example 6, approaching the properties of Example 2 while obtaining better impact strength than Examples 1 and 2. Additionally, compared to Examples 1 and 2, Example 3 has significantly improved impact strength without significantly changing other mechanical properties. Examples 4 to 5 demonstrate a significant reduction in flexural modulus and hardness even when the amount of COPE added remains less than 15%. Thus, Examples 3 to 5 illustrate the possibility of selecting the composition of the polyester mixture according to the requirements of the application.

[0067] Example 7: In this example, a particulate mixture of PET having an IV viscosity of 0.8 dL / g (considered by those skilled in the art as "bottle grade") and COPE having a Shore D hardness of 40 at a ratio of 5% by weight (as shown in Table 3 below) was prepared. The particulate mixture was then dried at 120 °C for 6 h and then injection molded into A1 dumbbell-shaped samples for mechanical testing. Curves of mechanical properties and shear thinning behavior in the molten state can be found in Table 3 below and in the accompanying drawings. This example has properties similar to Example 4 while maintaining an impact strength comparable to Examples 1 and 2, making it suitable for applications that require lower impact strength. The flexural properties of Example 7 are similar to those of Example 4, with a lower impact strength than Examples 1 and 2. These properties may be of interest in the application of polyester devices with anti-intrusion functions. This example also has a lower melt viscosity than Example 1, making it easier to process by injection molding, especially in the case of thin-walled components.

[0068] Example 8: In this example, a mixture of PET pellets having an IV viscosity of 0.8 dL / g (considered by those skilled in the art to be "bottle grade") and a poly(tetrahydrofuran) product having a molecular weight of 8000 g / mol at a ratio of 5% by weight (as shown in Table 3) (PTMEG - an example of this product is "Carbowax PEG 8000" from Dow Chemical Company) was prepared. The pellet mixture was then dried at 120 °C for 6 h and then injection molded into A1 dumbbell samples for mechanical testing. The mechanical properties are shown in Table 3 below. This example did not show an improvement over the properties shown in the foregoing examples and demonstrated that a two-phase elastomer is necessary to achieve the desired results. However, the addition of 5% PTMEG to the PET matrix resulted in a behavior of softening tensile strain, which was not observed in Examples 1 to 7 and can be used for functional components operating at higher strain rates, such as living hinges or film hinges.

[0069] Example 9: In this example, a pellet mixture of PET having an IV viscosity of 0.8 dL / g (considered by those skilled in the art to be "bottle grade") and a TPU polyurethane elastomer having a Shore A hardness of 71 at a ratio of 5% by weight (as shown in Table 3) (an example of this product is "Elastollan 1170A 10FC" from BASF) was prepared. The pellet mixture was then dried at 120 °C for 6 h and then injection molded into A1 dumbbell samples for mechanical testing.

[0070] In Examples 8 and 9, COPE (1 or 2) was replaced with PTMEG and TPU, respectively. It should be noted that protection for such polyester compositions produced from a mixture of PET (or similar) and PTMEG or TPU can be sought. Compositions in which PET (or similar) is mixed with multiple components from COPE, PTMEG, and TPU are also conceivable.

[0071] The mixture of dried pellets was also mixed by an extruder to obtain treated pellets. Curves of mechanical properties and shear thinning behavior in the molten state can be found in Table 3 and the accompanying drawings below. This example showed a reduction in flexural modulus and low impact strength comparable to those in Examples 4 and 7. The melt viscosity was also significantly reduced, making it a very good candidate for injection molding processes.

[0072] Table 3: Overview of the compositions and mechanical properties of Examples 1 to 9

[0073]

Claims

1. A dispensing device, which is intended to be mounted on a container to form a dispenser for a fluid product, the dispensing device being substantially composed of a polyester composition, the polyester composition being substantially composed of a mixture of component A and component B defined as follows: A: a copolyetherester elastomer (COPE), the copolyetherester elastomer being substantially composed of a hard segment of polyester and a soft segment of aliphatic polyether and having a hardness of less than 50 Shore D, and B: polyethylene terephthalate (PET) or copolyester, or a mixture of both.

2. A dispensing device, which is intended to be mounted on a container to form a dispenser for a fluid product, the dispensing device being free of polyolefins and comprising a plurality of elements, at least one element being substantially composed of a polyester composition, the polyester composition being substantially composed of a mixture of component A and component B defined as follows: A: a copolyetherester elastomer (COPE), the copolyetherester elastomer being substantially composed of a hard segment of polyester and a soft segment of aliphatic polyether and having a hardness of less than 50 Shore D, and B: polyethylene terephthalate (PET) or copolyester, or a mixture of both, and all other elements being made of component A or component B.

3. The dispensing device according to claim 1 or 2, wherein the copolyester is obtained by polymerizing at least one acid selected from terephthalic acid, 2,5-furandicarboxylic acid or isophthalic acid with an alcohol selected from ethylene glycol, cyclohexanedimethanol, propylene glycol and isosorbide, or by recycling a polymer composed of these monomers.

4. The dispensing device according to claim 1, 2 or 3, wherein the copolyester is a glycol-modified polyethylene terephthalate (PETG).

5. The dispensing device according to any one of the preceding claims, wherein the copolyester is selected from glycol-modified polycyclohexylene dimethylene terephthalate (PCTG), acid-modified polycyclohexylene dimethylene terephthalate (PCTA), polyethylene glycol-co-isosorbide terephthalate (PEIT) and polyethylene furandicarboxylate (PEF).

6. The dispensing device according to any one of the preceding claims, wherein component A is present in a weight ratio of 0.5% to 40%, advantageously 1% to 30%, and preferably 5% to 15%, and component B is present in a weight ratio of 60% to 99.5%, advantageously 70% to 99%, and preferably 85% to 95%.

7. The dispensing device according to any one of the preceding claims, wherein the hard segment of the polyester in component A is composed of butylene terephthalate units.

8. A dispenser for a fluid product, comprising the dispensing device according to any one of the preceding claims.

9. The dispenser for a fluid product according to claim 8, comprising a container made of component B, on which the dispensing device is mounted to dispense the fluid product contained in the container.

10. The dispenser according to claim 9, wherein the container is made of polyester, on which the dispensing device is mounted to dispense the fluid product contained in the container.

11. The dispenser for a product according to claim 9, wherein the container is made of polyolefin and the dispensing means is mounted on the container to dispense the fluid product contained in the container.

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