Polyester composition for a dispensing device

Abstract

A polyester composition consisting essentially of a mixture of components A and B defined as follows: A: a copolyether ester (COPE) elastomer consisting essentially of hard polyester segments and soft aliphatic polyether segments and having a hardness of less than 50 Shore D, and B: polyethylene terephthalate (PET) or a copolyester, or a mixture of the two. (Figure for abbreviation: single figure)

Description

Title of the invention: Polyester composition for a dispensing device technical field

[0001] The present invention relates to a polyester composition based on polyethylene terephthalate (PET) or similar materials that can be used in place of polyolefins (polyethylene (PE) or polypropylene (PP)), plastics commonly used in the manufacture of dispensing devices for the packaging industry, intended to be mounted on bottles, tubes, and jars for the packaging industry. Preferred areas of application include food, cleaning products, personal care, pharmaceuticals, and cosmetics. Context of the invention

[0002] The circular economy of plastic packaging necessitates the design of single-material packaging systems, i.e., systems whose various components are made of compatible polymer materials or materials from the same chemical family, in order to optimize their recycling. Currently, the majority of caps and dispensing devices on the market, intended for use on PET containers such as bottles, tubes, or jars, are either made of multi-material components or single-material components based on polyolefins, such as polyethylene or polypropylene. To our knowledge, no single-material polyester-based dispensing device for PET containers has yet been described in the literature. • PET description

[0003] Polyethylene terephthalate or PET is a semi-crystalline thermoplastic polyester obtained by polycondensation of two monomers: terephthalic acid and ethylene glycol, as shown in formula 1 below. Its main properties are impermeability to gases and liquids, chemical resistance, rigidity, and transparency.

[0004] Formula 1: Chemical structure of PET

[0005] PET is commonly used in various fields of application: packaging (water and soft drink bottles, fruit trays, cosmetic product bottles...), automobiles (car door handles, interior trim elements, air vents), electronics (sockets, lamp holders, boxes...) fuses). In addition to the properties mentioned above, PET is currently the most recycled plastic and is therefore a good candidate for the circular economy. • Comparison with other polymers

[0006] Table 1 below compares the properties of PET with those of other polymers such as polypropylene or polyethylene and ABS.

[0007] Table 1: Comparison of the mechanical properties of the types of plastic used by the packaging industry Properties Units Polyethylene terephthalate (PET) Polypropylene (PP) High-density polyethylene (HDPE) Acrylonitrile butylene styrene (ABS) PHYSICAL S Density 1.38 0.9 0.95 1.05 Permeability to T O2 (at lam, 20°C) mL.m2 / day 10 to 100 >1000 >1000 No data Water absorption (24h) % 0.1-0.2 0.01-0.1 0.005 - 0.01 0.2-0.6 MECHANICAL Hardness Shore D 83 67-74 63-67 75 Tensile modulus MPa 2300 - 2800 1000 - 1600 500- 1100 1600- 2600 Strength Charpy impact (notched) kJ / m2 3 4-20 4 20

[0008] Compared to polyolefins (PP or PE), PET has the following advantages: - Gas barrier properties - Good chemical and thermal resistance

[0009] In addition to the advantages mentioned above, it has other advantages, but also some disadvantages summarized in Table 2 below:

[0010] Table 2: Advantages and limitations of PET compared to PP PET compared to PP (Advantages and disadvantages) Advantages • More organized and efficient recycling channels • Grades approved for food contact • Good gas barrier properties • Good thermal and chemical resistance Disadvantages • Very different mechanical properties: twice as rigid as PP • More complicated injection molding process (preliminary drying step, etc.) • Susceptibility to hydrolysis and degradation at high temperatures

[0011] Despite its interesting properties and its positive effect in the circular economy, it is clear that pure PET could not be used to replace polyolefins, as illustrated in Table 1.

[0012] An object of the present invention is to provide new thermoplastic compositions intended primarily, but not limited to, for injection molding, having lower hardness, a lower tensile modulus, higher impact resistance, and lower molten viscosity compared to pure PET, and bringing these properties closer to those of PP while maintaining the recyclability of the resulting PET in the regular PET recycling stream. Another object of the present invention is to provide a range of polyester material formulations from which a material can be selected whose properties are adaptable to the needs of the design and manufacture of dispensing device components for the packaging industry, specifically intended for use on containers distributed by the packaging industry, and which can be produced from PET or copolyester. Summary of objects and invention

[0013] To fill these objects, the present invention proposes a polyester composition consisting essentially of a mixture of components A and B defined as follows:

[0014] A: a copolyether ester (COPE) elastomer consisting essentially of hard polyester segments and soft aliphatic polyether segments and having a hardness of less than 50 Shore D, and

[0015] B: a polyethylene terephthalate (PET) or a co-polyester, or a mixture of both.

[0016] The presence of functional additives is not excluded in the polyester composition, which in all cases remains essentially made up of A and B.

[0017] Advantageously, the copolyester is obtained by the polymerization of at least one acid selected from terephthalic acid, 2,5-furandicarboxylic acid or isophthalic acid with an alcohol selected from ethylene glycol, cyclohexanedimethanol, trimethylene glycol and isosorbide or recycling of a polymer composed of these monomers.

[0018] The co-polyester can be glycol-modified polyethylene terephthalate (PETG).

[0019] The copolyester can also be chosen from glycol terephthalate-modified polycyclohexylenedimethylene (PCTG), acid-modified polycyclohexylenedimethylene terephthalate (PCTA), polyethylene co-isosorbide terephthalate (PEIT), and polyethylene furanoate (PEF). Blends of several copolyesters from PETG, PCTG, PCTA, PEIT, and PEF can be considered. The use of a so-called "recycled" raw material, obtained through a mechanical or chemical process, and corresponding to the characteristics mentioned above, may also be considered.

[0020] According to another feature of the invention, component A is present in a mass ratio of 0.5% to 40%, advantageously from 1% to 30% and preferably from 5% to 15%, and component B is present in a mass ratio of 60% to 99.5%, advantageously from 70% to 99% and preferably from 85% to 95%.

[0021] According to another aspect of the invention, in component A, the hard segment of the polyester may be made up of butylene terephthalate units. It is also possible to replace butylene terephthalate with ethylene terephthalate, without departing from the scope of the invention.

[0022] The composition obtained by adding the elastomer (COPE) to the polyester matrix (PET or similar) will exhibit a lower tensile modulus, lower hardness, improved impact resistance and better viscosity in the molten state compared to a pure polyester matrix (PET for example) or compared to polypropylene, which will make it better suited for implementation, in particular, but not limited to, by injection molding, and for the design of dispensing systems intended for use on polyester containers, which may also come from a recycling stream.

[0023] The invention also defines a dispensing device, such as a cap, an applicator, or more generally a monobloc or multi-element dispensing device, intended to be mounted on a polyester container to constitute a dispenser for a fluid product, the dispensing device being essentially made up of the polyester composition defined above, essentially made up of A and B.

[0024] A fluid product is defined here as any substance that can flow, and therefore includes products in liquid form, and powdered or granular solids.

[0025] The invention also defines a distribution device intended to be mounted on a polyester container to constitute a dispenser for fluid product, the dispensing device being free of polyolefin and comprising several elements, at least one element being essentially made from the polyester composition defined above, essentially made up of A and B, all other elements being made from component A or B.

[0026] The invention further defines a fluid product distributor comprising a monobloc or multi-element distribution device, as defined above.

[0027] Advantageously, the fluid product dispenser comprises a container made from component B, on which the dispensing device is mounted to dispense the fluid product contained in the container. Alternatively, the container may be made of polyester or polyolefin. As a variant, it may also be made of glass, metal, ceramic, etc.

[0028] [Single Fig.] The single figure is a graph representing the curves of the com shear-thinning behavior measured by capillary rheometer at 275°C for samples 1, 4 and 9, and at 205°C for sample 2. Detailed Description

[0029] The present invention relates to a polyester composition that can be used in a suitable plastics forming process, for example, injection molding. Preliminary mixing using a compounding or extrusion unit may or may not be carried out before using the polyester mixture in an injection molding machine, an injection blow molding, extrusion, extrusion blow molding, calendering, or thermoforming process, or any other suitable means for the processing and implementation of polymers. Appropriate drying to a rate of less than 0.05% by mass is preferably carried out before any high-temperature treatment of the polyester materials.

[0030] The main polyester matrix shall 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, trimethylene glycol, or isosorbide. Such copolyesters include materials known to those skilled in the art by their acronyms: PETG, PCTG, PCTA, PEIT, PEF, etc. Such polyesters can be used for the manufacture of containers, bottles, tubes, and jars, generally intended for mass distribution and the packaging industry. This polyester matrix may also be sourced from a recycling stream, provided its chemical composition always meets the aforementioned criteria.

[0031] An elastomer from one of the families described below will be mixed with the main polyester matrix, in an amount of between 0.5 and 40% by mass, advantageously preferably between 1% and 30% and preferably from 5% to 15%. This elastomer preferably has a Shore D hardness of less than 50 units, and belongs to the family of polyester-ether (COPE) elastomers, which are thermoplastic copolymer elastomers, for which the building blocks are linked together by ester chemical bonds, and formed of two microstructural phases:

[0032] Rigid phase (ester-based rigid segments): Polymer in crystalline form that ensures the cohesion and strength of the material. The rigid phase of COPE will most often be PBT (polybutylene terephthalate), but can also be rigid segments of PET (polyethylene terephthalate).

[0033] Flexible phase (ether-based flexible segments): Polymer in the rubbery state which gives the material its elastomeric character, most often a polyether glycol such as, but not limited to, polytetramethylene ether glycol (PTMEG) or polyethylene glycol.

[0034] It should be noted that COPE can be replaced, depending on the type of application and the properties required, by one of the following three chemical families:

[0035] 1) Thermoplastic polyurethane elastomers (TPU)

[0036] TPUs have a microstructure similar to that of COPE. They are materials whose bonds between building blocks are urethane bonds and are formed of two microstructural phases:

[0037] The rigid phase (rigid polyurethane-based segment): A polymer in crystalline form that ensures the cohesion and strength of the material. The rigid phase of TPU is most often, but not exclusively, composed of methylene diisocyanate (MDI) or toluene diisocyanate (TDI) associated with a chain-extending diol molecule, most often, but not exclusively, butanediol (BDO).

[0038] Flexible phase (flexible segment based on ether or polyester): Polymer in the rubbery state which gives the material its elastomeric character, which may be a polyether glycol, such as, but not limited to, PTMEG (polytetramethylene ether glycol), or a macrodiol based on aliphatic polyester such as, but not limited to, polycaprolactone or polybutylene succinate (PBS).

[0039] 2) Polyetheramide elastomers (COPA)

[0040] COPAs are thermoplastic copolymer elastomers whose bonds between building blocks are amide bonds and are formed of two microstructural phases:

[0041] Rigid phase (polyamide-based rigid segment): A polymer in crystalline form that provides the cohesion and strength of the material. The rigid phase of COPA is most often polyamide 12, obtained, without limitation, by polycondensation of aminolauric acid or ring opening of laurolactam.

[0042] Flexible phase (ether-based flexible segment): Polymer in a rubbery state which gives the material its elastomeric character, which can be a polyether glycol, such as PTMEG (Polytetramethylene Ether Glycol), but not only.

[0043] 3) Glycols, also called aliphatic polvethers

[0044] Polyethylene glycol (PEG) or polytetrahydrofuran (PTMEG) are flexible molecules having the following chemical structure:

[0045] Example of the chemical structure of glycols (here polyethylene glycol)

[0046] It is preferable to use in the mixture products whose average molar mass is at least 4000 g / mol, in order to minimize migration into the products contained by the dispenser. Examples

[0047] • Test procedures

[0048] Implementation: The raw material formulations were first mixed into granules in the appropriate proportions and then dried for 6 hours at 120°C before any high-temperature processing. The dried granule mixtures were then either injection molded to form dumbbell-shaped samples for mechanical testing or extruded and formed into granules for rheological testing.

[0049] Density measurement: The density measurement was carried out according to the instructions of method A of ISO 1181 using a balance equipped with a wire density measurement kit.

[0050] Mechanical tests: In accordance with ISO 527, aluminum dumbbells were used to measure the tensile properties of the various examples shown below, obtained at a tensile speed of 50 mm / min. Impact resistance values ​​were obtained in accordance with ISO 79. Hardness values ​​were obtained in accordance with ISO 868.

[0051] Rheological test: The molten viscosity curves as a function of shear rate were obtained via a capillary rheometer and measured at a temperature of 275°C. All samples in granular form were dried at 120°C for 6 hours before measurement. • Results

[0052] Example 1: In this example, a control sample made of 100% PET, produced by the polymerization of terephthalic acid and ethylene glycol, with a viscosity IV of 0.8 dL / g, which is considered "bottle grade" by the packaging industry, was dried for 6 hours at 120°C before being injection molded into Al dumbbell shapes for mechanical testing. The dried granules of this material were also mixed using an extruder to obtain treated granules. This example has been included in this document solely for comparison with the following examples. The mechanical properties and the melt shear-thinning behavior curve can be found in Table 3 and the graph below.

[0053] Example 2: In this example, a control sample made of 100% polypropylene copolymer, with a melt flow index considered to be of "injection grade," suitable for injection molding of bottle caps and closures by the packaging industry, was injection molded into dumbbell-shaped samples for mechanical testing. Granules of this material were also mixed using an extruder to obtain conditioned granules. This example has been included in this document solely for the purpose of comparison with the following examples. The mechanical properties and the melt shear-thinning behavior curve can be found in Table 3 and the graph below. The mechanical properties and viscosity of the melt are very different from those of Example 1, illustrating the gap that this invention aims to bridge between the two materials.

[0054] Examples 3 to 6: In these examples, mixtures of granules of a PET with a viscosity IV of 0.8 dL / g (considered to be "bottle grade" by those skilled in the art), and a COPE with a Shore D hardness of 25 (an example of such a product is Celanese's Riteflex 425), designated COPE1 in Table 3 below, at a ratio ranging from 1 to 30% by weight, as indicated in Table 3, were produced. The granule mixtures were then dried for 6 hours at 120°C before being injection molded into dumbbell-shaped samples Al for mechanical testing. The dried granule mixtures were also blended using an extruder to obtain treated granules. The mechanical properties are shown in Table 3 below.Increasing the amount of COPE in the samples allows for adjustment of the material's mechanical properties and, in the case of Example 6, brings it closer to the properties of Example 2 while achieving better impact resistance than Examples 1 and 2. Furthermore, Example 3 exhibits significantly improved impact resistance compared to Examples 1 and 2, without significantly altering the other mechanical properties. Examples 4 and 5 demonstrate a notable decrease in flexural modulus and hardness, even though the amount of COPE added remains below 15%. Examples 3 through 5 thus illustrate the possibility of selecting the polyester blend composition according to the application's requirements.

[0055] Example 7: In this example, a mixture of granules of a PET with a viscosity IV of 0.8 dL / g (considered "bottle grade" by those skilled in the art), and a COPE with a Shore D hardness of 40 (an example of such a product is Celanese's "Riteflex 640A"), designated COPE2 in Table 3 below, was produced at a 5 wt% ratio, as shown in Table 3. The granule mixtures were then dried for 6 h at 120°C before being injection molded into Al dumbbell-shaped samples for mechanical testing. The mechanical properties and the melt shear-thinning behavior curve can be found in Table 3 and the graph below. This example exhibits properties similar to those of Example 4, while maintaining impact strength comparable to that of Examples 1 and 2, making it useful in applications where lower impact strength is required. The bending properties of example 7 are similar to those of example 4, with lower impact resistance compared to examples 1 and 2.These properties could be useful in polyester device applications with an anti-burglary function. This example also exhibits a reduced molten viscosity compared to example 1, making it easier to process by injection molding, particularly for thin-walled components.

[0056] Example 8: In this example, a mixture of PET granules with a viscosity IV of 0.8 dL / g (considered "bottle grade" by those skilled in the art) and flakes of a polytetrahydrofuran product (PTMEG—an example of this product is "Carbowax PEG 8000" from Dow Chemical Company) with a molecular weight of 8000 g / mol was produced at a ratio of 5% by weight, as shown in Table 3 below. The granule mixture was then dried for 6 h at 120°C before being injection molded into Al dumbbell samples for mechanical testing. The mechanical properties are shown in Table 3 below. This example does not demonstrate the change in properties shown by the preceding examples and proves that a two-phase elastomer is necessary to obtain the desired results.However, the addition of 5% PTMEG to a PET matrix resulted in the appearance of a softening behavior of tensile deformation which is not observed on examples 1 to 7, and which could be used on functional components working at higher strain rates such as live hinges or film-type hinges.

[0057] Example 9: In this example, a mixture of PET granules with a viscosity IV of 0.8 dL / g (considered "bottle grade" by those skilled in the art), and a TPU polyurethane elastomer with a Shore A hardness of 71 (an example of such a product is BASF's "Elastollan 1170 A 10 FC") at a ratio of 5% by weight, as shown in Table 3 below, was produced. The granule mixtures were then dried for 6 hours at 120°C before being injection molded into Al dumbbell samples for mechanical testing.

[0058] In Examples 8 and 9, COPE (1 or 2) has been replaced by PTMEG and TPU, respectively. It should be noted that protection could be sought for such a polyester composition resulting from the mixture of PET (or similar) and PTMEG or TPU. A composition mixing PET (or similar) and several components from among COPE, PTMEG, and TPU can also be considered.

[0059] The dried granule mixtures were also blended using an extruder to obtain treated granules. The mechanical properties and the shear-thinning behavior curve in the melt state can be found in Table 3 and the graph below. This example showed a decrease in the flexural modulus comparable to Examples 4 and 7, and low impact strength. The viscosity of the melt is also significantly reduced, making it a very good candidate for injection molding.

[0060] Table 3: Summary of the composition and mechanical properties of examples 1 to 9 Example number: 1 2 3 4 5 6 7 8 9 Composition Materials % by mass PET 100 - 99 95 85 70 95 95 95 PP Copolymer - 100 - - - - - - - COPE 1 - - 1 5 15 30 - - - COPE 2 - - - - - - 5 - - PTMEG - - - - - - - 5 - TPU - - - - - - - - 5 Measurements Properties Units Density g / cm3 1.33 0.9 1.33 1.33 1.32 1.29 1.33 1.35 1.33 Shore D Hardness 77 61 77 76 71 69 74 74 74 Flexural Modulus MPa 2493 130 0 2487 2224 1995 1489 230 1 2465 23 44 Impact resistance (on bar) kJ / m2 6.9 9.4 8.8 11 12.2 23.2 4.1 1.7 2.6 notch)

Claims

Demands

1. Dispensing device for mounting on a container to constitute a dispenser for a fluid product, the dispensing device being essentially made from a polyester composition consisting essentially of a mixture of components A and B defined as follows: A: a copolyether ester elastomer (COPE) consisting essentially of hard polyester segments and soft aliphatic polyether segments and having a hardness of less than 50 shore D, and B: a polyethylene terephthalate (PET) or a copolyester, or a mixture of the two.

2. Dispensing device for mounting on a container to constitute a dispenser for a fluid product, the dispensing device being free of polyolefin and comprising several elements, at least one element being essentially made from a polyester composition consisting essentially of a mixture of components A and B defined as follows: A: a copolyether ester elastomer (COPE) consisting essentially of hard polyester segments and soft aliphatic polyether segments and having a hardness of less than 50 shore D, and B: a polyethylene terephthalate (PET) or a copolyester, or a mixture of the two, all other elements being made from component A or B.

3. Dispensing device according to claim 1 or 2, wherein the co-polyester 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, trimethylene glycol and isosorbide, or by recycling a polymer composed of these monomers.

4. Dispensing device according to claim 1, 2 or 3, wherein the co-polyester is glycol-modified polyethylene terephthalate (PETG).

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

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

7. Dispensing device according to any one of the preceding claims, wherein, in component A, the hard polyester segment is made up of butylene terephthalate units.

8. Fluid product dispenser comprising a dispensing device according to any one of the preceding claims.

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

10. Dispenser according to claim 9, in which the container is made of polyester, on which the dispensing device is mounted to distribute the fluid product contained in the container.

11. Distributor according to claim 9, in which the container is made of polyolefin, on which the distribution device is mounted to distribute the fluid product contained in the container.

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