Packaging arrangement for an optionally hydrogenated nitrile rubber

Abstract

The present invention relates to a packaging arrangement (10) for enclosing and storing a polymer (20), wherein the polymer comprises an optionally hydrogenated nitrile rubber, wherein the optionally hydrogenated nitrile rubber has complex modulus G* measured at 100°C and at 1 Hz frequency of ≤ 100 kPa, wherein the packaging arrangement (10) comprises an inner packaging (12) and an outer packaging (14), wherein the inner packaging (12) comprises a main layer (16) and optionally a contact layer (18) for coming into direct contact with the polymer (20), wherein the outer packaging (14) at least partly encloses the inner packaging (12), and wherein the outer packaging (14) is formed from paper, preferably from cardboard, and wherein at least the main layer (16) of the inner packaging (12) has no softening point according to the ring-and-ball-test below 120°C, and the main layer (16) or if provided the contact layer (18) has a release force of the material to be packed of ≤ 0,2 N / 25mm.

Description

[0001] P11600130-W02

[0002] Packaging arrangement for an optionally hydrogenated nitrile rubber

[0003] The present invention relates to safe and clean packaging of optionally hydrogenated nitrile rubbers, in particular of sticky low molecular weight hydrogenated nitrile rubbers (HNBR) having a low Mooney viscosity. More specifically, the present invention relates to a packaging arrangement comprising a specific inner packaging and a specific outer packaging at least partly enclosing the inner packaging.

[0004] Some polymers are very sticky at room temperature or also at elevated temperatures, and they have a strong tendency for cold flow, but they are also relatively viscous unlike liquid polymers. Its is difficult to find a packaging arrangement which allows securely packing said polymers allowing maintaining the value of the polymers, thereby meeting all requirements, such as easy packing and unpacking and preventing contamination.

[0005] Easy release properties may require to apply an abhesive coating which often is based on silicones from emulsion, solution or solvent-free which, however, contain free silicone oil. Further, known are fluorinated products which, however, only show very limited sustainability. There is, thus, potential for improvements in commercially available packaging systems for polymers and under these especially for optionally hydrogenated nitrile rubber (HNBR) being very sticky.

[0006] CN 1254315 A describes a multi-layered plastic container that is especially usable for viscous liquid products. In particular the plastic container is made by blow-molding an extruded parison having an outer polyolefin layer, an intermediate adhesive layer, and an inner product-contacting layer of a polyester material such as glycol-modified polyethylene terephthalate. In another embodiment, the plastic container is extrusion blow-molded from a four-layer parison comprised of an outer polyolefin layer, an intermediate adhesive layer, an inner polyester layer, and a scrap or regrind layer comprised of a blend of these three layers recovered from the flash removed from the finished container. However, this container seems to have no usability for a product which is introduced in a molten state and which shall be removed from the container in a non-molten state, i.e. at room temperature.

[0007] There is thus still room for improvements regarding providing a packaging arrangement which allows filling in a polymer when the polymer is in a molten state and thus has a comparably high temperature but may be stored and removed safely from the packagingP11600130-W02

[0008] arrangement when the polymer is present at room temperature and may thus have a very high viscosity or may even be solid.

[0009] It is thus an object of the present invention to provide a packaging arrangement which allows filling it with very sticky optionally hydrogenated nitrile rubber both in cold and hot conditions, allowing a safe storage of the polymer and finally allowing secure and reliable removing the polymer from the packaging arrangement also at room temperature and when the polymer has a comparably high viscosity or is even present as a solid. In particular, further, a good sustainability is desired.

[0010] Summary

[0011] The present invention relates to the safe and clean packaging of low molecular weight optionally hydrogenated nitrile rubbers ((H)NBR). More specifically, the present invention deals with an inner packaging to contain and protect the valuable (H)NBR product thus maintaining its value during storage and transportation and an outer packaging giving high stability for storage. A packaging arrangement according to the present invention allows a specific optionally hydrogenated NBR, i.e.one with a high stickiness as defined by a complex modulus G* measured at 100°C and at 1 Hz frequency of < 100 kPa to be securely packed and unpacked, either in hot or cold condition, thereby reducing the risk of contaminations of the polymer and thus maintaining its value. Apart from that, the present invention allows a very sustainable solution.

[0012] In one aspect, the present invention provides a packaging arrangement for enclosing and storing a polymer, wherein

[0013] the polymer comprises an optionally hydrogenated nitrile rubber, wherein the optionally hydrogenated nitrile rubber has complex modulus G* measured at 100°C and at 1 Hz frequency of < 100 kPa, wherein

[0014] the packaging arrangement comprises

[0015] an inner packaging and

[0016] an outer packaging, wherein

[0017] the inner packaging comprises a contact layer for coming into direct contact with the polymer and optionally a main layer, wherein

[0018] the outer packaging at least partly encloses the inner packaging and wherein the outer packaging is formed from paper, in particular from cardboard, and wherein

[0019] at least the main layer of the inner packaging if provided has no softening point accordingP11600130-W02

[0020] to the ring-and-ball-test below 120°C, and the contact layer has a release force of the material to be packed of < 0,2 N / 25mm.

[0021] In a further aspect, the present invention provides an arrangement comprising the packaging arrangement like described and an optionally hydrogenated nitrile rubber, wherein the packaging arrangement is filled with the optionally hydrogenated nitrile rubber such, that the optionally hydrogenated nitrile rubber is in contact with the inner packaging, wherein the optionally hydrogenated nitrile rubber has a complex modulus G* measured at 100°C and at 1 Hz frequency of < 100 kPa, wherein the inner packaging is in direct contact with the optionally hydrogenated nitrile rubber and the outer packaging at least partly encloses the inner packaging.

[0022] In a still further aspect, the present invention provides a method of packing a polymer, wherein the polymer comprises an optionally hydrogenated nitrile rubber, wherein the optionally hydrogenated nitrile rubber has a complex modulus G* measured at 100°C and at 1 Hz frequency of < 100 kPa and, wherein the method comprises the steps of:

[0023] i) Providing a packaging arrangement like described;

[0024] ii) Pouring the polymer into the inner packaging, wherein the polymer is in a fluid state; iii) Closing the inner packaging to completely enclose the polymer; and

[0025] iv) Providing the outer packaging outside of the inner packaging.

[0026] Detailed Description

[0027] In the following description norms may be used. If not indicated otherwise, the norms are used in the version that was in force on December 20, 2024. If no version was in force at that date because, for example, the norm has expired, then the version is referred to that was in force at a date that is closest to December 20, 2024.

[0028] In the following description the amounts of ingredients of a composition or polymer may be indicated interchangeably by “weight percent”, “wt. %” or “% by weight”. The terms “weight percent”, “wt. %” or “% by weight” are used interchangeably and are based on the total weight of the composition or polymer, respectively, which is 100 % unless indicated otherwise.

[0029] The term “phr” means parts per hundred parts of rubber, i.e. , the weight percentage based on the total amount of rubber which is set to 100%.P11600130-W02

[0030] Ranges identified in this disclosure include and disclose all values between the endpoints of the range and also include the end points unless stated otherwise.

[0031] The present invention relates to the safe and clean packaging of low molecular weight optionally hydrogenated nitrile rubber (NBR, HNBR). More specifically, it deals with the inner packaging to contain and protect the valuable HNBR product.

[0032] The present invention provides a packaging arrangement for enclosing and storing a polymer, wherein

[0033] the polymer comprises an optionally hydrogenated nitrile rubber, wherein the optionally hydrogenated nitrile rubber has complex modulus G* measured at 100°C and at 1 Hz frequency of < 100 kPa, wherein

[0034] the packaging arrangement comprises

[0035] an inner packaging and

[0036] an outer packaging, wherein

[0037] the inner packaging comprises a contact layer for coming into direct contact with the polymer and optionally a main layer, wherein

[0038] the outer packaging at least partly encloses the inner packaging and wherein the outer packaging is formed from paper, in particular from cardboard, and wherein

[0039] at least the main layer of the inner packaging if provided has no softening point according to the ring-and-ball-test below 120°C, and the contact layer has a release force of the material to be packed of < 0,2 N / 25mm.

[0040] Such a packaging arrangement allows significant advantages over solutions of the prior art.

[0041] Optionally hydrogenated nitrile rubbers (NBR or HNBR), such as optionally hydrogenated nitrile rubbers which may be formed from acrylonitrile and butadiene as monomer units, are known as such for a plurality of applications. The high value especially of specialty applications often shows the need for very high requirements for cleanliness and purity demands of such polymers. Consequently, not only the manufacturing process as such should result in clean products, but there are also high demands for packaging. This is especially true for low Mw HNBR which also has a low Mooney viscosity as these products are especially demanding to be packed and stored in a suitable manner. These polymers are very sticky at room temperature (RT), they have a strong tendency for coldP11600130-W02

[0042] flow, but they are also relatively viscous unlike liquid polymers.

[0043] With this regard, the measurement of Mw by GPC, or the conventional Money measurement, give a vague idea if an (H)NBR product will have high stickiness or cold flow so that the packaging arrangement according to the invention needs to be used. However, surprisingly, it was found that a high stickiness (H)NBR requiring the inventive packaging will have a complex modulus G* measured at 100°C and at 1 Hz frequency with a DMTA (Mettler) which is 100 kPa and below, for examples 50 kPa and below, such as 40 kPa and below. The stickiness is an important factor for providing a respective packaging arrangement.

[0044] With regard to the complex modulus G*, a lower value indicates less shear resistance, easier deformation and better flowability under stress for example when pouring the material out when under the influence of its own gravity. The complex modulus is dependent on the frequence or speed of the periodic stress. The inventors found when taking the modulus value at a frequency of 1 Hz then, both the speed of filling the polymer into the inventive packaging and the flow of the polymer into the inner packaging is well represented. In addition, the stickiness is typical a process where the polymer is detached from its packaging with a certain speed which can also be broadly in the range of one Hz. The complex modulus is measured at 100°C which is broadly in the range when the polymer has contacted the inner packaging and begins to cool down. In this way the adhesion and the wetting of the polymer to the inner packaging is well represented by a single measurement.

[0045] The low Mw HNBR can be produced from low Mw nitrile rubbers (NBR) which are hydrogenated in a solution process. Once the process solvent, such as NMP, is removed after hydrogenation, the still hot low Mw HNBR can be pumped to a filling device. As especially (H)NBR with a low Mw, especially below 150 kg / mol, cannot be pelletized anymore and need to be warm filled into the packaging unit. Depending on the customer requirements, the packaging size can vary from for example 5 kg to 200 kg.

[0046] At the customer site, the outer packaging will be removed, possibly by an automatic process without problems. According to the present invention, it is possible that also the inner packaging may be cleanly stripped away from the products which is then filled into dissolver vessels. It should be noted that for specialty applications, packaging films need to be completely removed from the packed material. Traces of packaging materials suchP11600130-W02

[0047] as torn pieces are not allowed to remain in the product.

[0048] With this regard, it can securely be excluded that contaminations based on the packaging and specifically of a release coating are held within the polymer. Thus, the quality of polymers packed with a packaging arrangement as described can be especially high. A packing arrangement is therefore shown which is particularly suitable for a polymer which comprises an optionally hydrogenated nitrile rubber, wherein the optionally hydrogenated nitrile rubber has a complex modulus G* measured at 100°C and at 1 Hz frequency of < 100 kPa and optionally a Mooney viscosity MU of < 30 MU, and a molecular weight Mw of < 150 kg / mol, such as > 5 kg / mol.

[0049] In order to solve this object, the packaging arrangement comprises an inner packaging and an outer packaging, wherein the inner packaging comprises a contact layer for coming into direct contact with the polymer and optionally a main layer, wherein the outer packaging at least partly encloses the inner packaging and wherein the outer packaging is formed from paper, in particular from cardboard, and wherein at least the main layer of the inner packaging if provided has no softening point according to the ring-and-ball-test below 120°C, and the contact layer has a release force of the material to be packed of < 0,2 N / 25mm.

[0050] According to the invention, the inner packaging and in particular the contact layer comes into direct contact with the polymer and allows easy inflow of the polymer, thereby preventing deformation due to the high softening point and a good release of the packaging arrangement due to the low release fore and the outer packaging allows high stability and easy string and stacking.

[0051] It was surprisingly found that most common tests are not or at least not fully suitable for taking a prediction and thus a secure and reliable teaching which packaging arrangement might provide a secure and reliable packing for storing especially the above-defined polymers, i.e. polymers comprising optionally hydrogenated nitrile rubbers having a complex modulus G* measured at 100°C and at 1 Hz frequency of < 100 kPa and optionally a Mooney viscosity Mu of < 30 MU, and a molecular weight Mw of < 150 kg / mol. According to the present invention, a packaging arrangement is provided which reflects the above needs and ensures a safe and reliable packaging.

[0052] Especially the above definitions, i.e. no softening point according to the ring-and-ball-testP11600130-W02

[0053] below 120°C; and a release force of the material to be packed of < 0.2 N / 25mm provides a solution which secures upholding the properties of the polymer to be packed, is advantageous with regard to sustainability and further allows easy and reliable packing as well as unpacking.

[0054] With this regard, it was surprisingly found that especially the generally unusual parameter of the softening according to the ring and ball test point gives a reliable prediction that the present invention shows its advantages. It has to be noted that in case no main layer is present, this parameter may be fulfilled by the outer packaging.

[0055] According to the prior art, there are several conventional test methods to investigate the change of mechanical properties of thermoplastic materials with temperature. However, it was found by the inventors that the softening point is very suitable to judge if an inner packaging, such as a base liner material, can hold the (H)NBR product when packaged in the warm state. Especially, when the outer more rigid packaging has folds, creases or gaps, then the softening point can predict until which temperature the product is safely kept inside the inner packaging as well as the outer packaging. Beyond the softening point, measured by the ring-and-ball test, the inner packaging will sink or melt away into the gaps and with it the packaged (H)NBR. Thus, beyond the softening point, the packaged product will not be safe anymore from contamination, or it will be more difficult to get out of the packaging. The softening point is conventionally used to characterize tackifier resins but is not used for the present application.

[0056] Thermoplastic materials, for example, can possess a glass transition temperature (Tg) and a degree of crystallinity at the same time. In some cases, the thermoplastic film material can have a so-called cold crystallization which creates sudden increase of strength when the cold crystallization temperature is reached. Apart from that, the thickness of the respective material also plays an important role as well as further parameters, such as its fastening, its arrangement, etc. Thus, there is a difficulty to select a suitable material for the inner packaging solely on the basis of thermal phase transitions such as melting point (Tm) or Tg. In contrast, using the defined parameters according to the present invention can therefore much more efficiently focus the arising problem especially when packing the specific polymers as described. According to the present invention, it is not required to exclude materials by Tg, or Tm, for example, which might anyhow fulfill all requirements when defining the materials by the softening point according to the ball test. In other words, the ring and ball test combines a plurality ofP11600130-W02

[0057] parameters of the respective material, next to simple phase transitions and thus allows a clear and reliable teching in the sense of the present invention.

[0058] In addition to this, when films are oriented, either mono-axial or biaxially, then there can be sudden shrink from crystallite melting which leads to severe distortion of the film. Such a behavior also is considered according to the invention.

[0059] According to the invention, it is thus very advantageous that the inner packing is provided such, that at least the main layer of it has no softening point according to the ring-and-ball-test below 120°C; preferably below 150°C.

[0060] Further, the release force is very important for unpacking (H)NBR, both manually and via robots. According to the present invention, it is important that a release force of the material to be packed of < 0.2 N / 25mm. This shall mean that a release force from the packed (H)NBR to the contact surface of the inner package lies in the above-defined range.

[0061] The outer packaging, and thus the outside surface of the packaging, is further formed from paper, such as of cardboard. In particular, various paper liner such as clay coated Kraft (CCK) paper, glassine (GLS), super calandered Kraft (SCK) paper, machine finished (MF), machine glazed (MG) Kraft paper or especially preferred corrugated cardboard may be used. Such materials for use as outer packaging have an outstanding mechanical stability, thereby anyhow being lightweight, so that these materials may be especially preferred for packaging and transport purposes. The stacking of the boxes on pallets can follow industrial practice, however, the boxes might also be stabilized against bulging to outside, such as by strong side walls or a tight wrapping with a film, or by using metal brackets. Further, a plurality of layers of the respective material may be provided which may be determined by the strength of the boxes and the need to limit the pressure on the packaged material. These materials further show a very good sustainability.

[0062] In general, convention carboard boxes may be used for the outer packaging, which have the advantages of easy handling, mostly by simply folding, and a mechanically stable form. Therefore, cardboard is lightweight allowing good transport properties. Further, cardboard is advantageous with regard to sustainability.

[0063] According to an embodiment, the outer packaging is foldable to a closed container with aP11600130-W02

[0064] storage volume, wherein the container has a ground area, at least one side area and a top area, wherein the container can be opened and closed by folding the top area. In particular, the ground area is that area on which the packaging arrangement stands when it is filled. Accordingly, for the filling process, the container may be opened by folding the top area, i.e. having folding lines at the top area or next to the top area so that the top area may be folded in part or completely to open or close the container. The ground area and, correspondingly, the top area can be rectangular or square in shape, so that the number of side areas is adapted to this shape, i.e., there may be four side areas, also called sidewall areas, for example. Therefore, the form and functionality of the outer packaging may be adapted to conventional carboard containers.

[0065] It may further be preferred, that wherein the packaging arrangement has an opening for introducing the polymer into the storage volume of the packaging arrangement and for removing the polymer from the storage volume of the packaging arrangement, the opening having a size of at least 100 cm2, for example in a square form 10cm x 10 cm. In particular the whole top area may form the opening. This allows easy filling of the packaging arrangement with a polymer and further particularly allows easy removal even in case the polymer is removed from the packaging arrangement in a state in which it is solid.

[0066] According to an embodiment, the inner packaging comprises a main layer being coated with a contact layer. This embodiment allows a very high adaptability of the specific solution, as the inner layer may provide a sufficient stability in terms of the softening point, whereas the contact layer may provide the desired release force. Therefore, a very broad application range with lots of suitable products is possible.

[0067] The contact layer may also be provided on the inner side of the outer package, thus leaving out the inner layer. More preferred is to fully provide the main layer with a contact layer. Most importantly, the contact layer comes into direct contact with the polymer to be stored. A preferred thickness of the main layer lies in the range of <150pm, such as in the range of > 40 to < 120 pm, whereas a preferred thickness of the contact layer lies in the range of <15pm, such as in the range of > 1 to < 15 pm, preferably in the range of > 2 to < 7 pm.

[0068] However, it is of course also possible that the inner package consists of the contact layer, in case the respective material may show especially the defined release force. ForP11600130-W02

[0069] example, the contact layer may be coated to the inside of the outer packaging.

[0070] Very advantageous examples fulfilling the specific requirements of the main layer comprise materials selected from the group consisting of polypropylene, such as isotactic polypropylene; polyethylene, such as high-density polyethylene (HDPE); polyester, such as polyethylene terephthalate (PET); polyamide (PA); polystyrene (PS); or paper. It was shown that the above-described materials fulfill the above-named specific properties to be especially usable in the sense of the present invention, wherein, however, a contact layer provided on the main layer may be preferred.

[0071] However, due to its thermomechanical properties, paper may be especially preferred.

[0072] With regard to the contact layer, it has surprisingly shown that especially silicon having a curing degree of > 75% is especially preferred. This is mainly due to the fact that despite the stickiness of the (H)NBR which is relevant in the present invention, especially good release properties can be reached. Further, as a very high curing degree is provided, the risk of contaminating the valuable polymer by silicon oil is excluded or at least significantly reduced as respective cured silicon materials re essentially free of silicon oil which might migrate into the polymer. With this regard, the higher the curing degree is, the less silicone oil will be present. Therefore, curing degrees of the silicone in the range of > 90% or even > 98% might be especially preferred. Generally, silicon, or silicon rubber, respectively, may be cured by using a platinum-based curing system as known in the art.

[0073] It may further be particularly preferred that the inner packaging and the outer packaging are arranged as a separate parts. This shall particularly mean that the inner packaging and the outer packaging can be moved or in other words shifted against each other and may be separated from each other without causing damage to the respective packaging, in case the inner packaging and the outer packaging are not fixed to each other.

[0074] Therefore, the inner packaging may as an example be formed an inlay product, which may be introduced into the outer package. With this regard, the inner packaging may for example just be laid into the outer package, or it may be fastened to the outer package, for example by means of a glue layer. A separate inner packaging such as in the form of a release liner allows a free choice of the outer packaging in shape and size. This in turn improves the implementation of the present invention in known systems so that the usability is especially high. This allows an especially easy manufatcuring process, as standard outer packagings, such as cardboxes, might be used without the additional stepP11600130-W02

[0075] of coating them.

[0076] Apart from that, it can be ensured that the inner packaging covers all openings or folding lines of the outer package which are present for example when folding a cardboard box, so that it may especially reliably be prevented that polymer flows out of the packaging arrangement.

[0077] The release film can be brought into the form of a bag, then adapting its shape to the bottom and the walls of the outer packaging.

[0078] As indicated above, it may further be provided that the inner packaging may be fixed to the outer packaging. This may be realized for example in case the outer packaging is coated with the inner packaging, or in case the inner packaging, which is described above as a separate part, may be fixed to the outer packaging by means of an adhesive, for example. According to this example, the main layer may be fixed to the outer packaging by means of an adhesive, so that the contact layer provides the inner surface of the packaging arrangement.

[0079] According to a further preferred embodiment, the main layer of the inner packaging, if provided, has a melting temperature or a glass transition temperature in the range of > 120°C, preferably of > 125°C, such as of > 140°C, even more preferably of > 150°C.

[0080] Although the softening point is a prferred parameter of the present invention, the main layer may also have a suitable Tm or Tg. This embodiment thus further helps ensuring the advantages of the present invention.

[0081] According to an especially preferred embodiment, the inner packaging comprises a main layer comprising paper, a contact layer comprising silicon having a curing degree of > 75% and wherein the outer packing comprises a cardboard material.

[0082] The present invention further relates to an arrangement comprising the packaging arrangement as described and an optionally hydrogenated nitrile rubber, wherein the packaging arrangement is filled with the optionally hydrogenated nitrile rubber such, that the optionally hydrogenated nitrile rubber is in contact with the inner packaging, wherein the optionally hydrogenated nitrile rubber has a complex modulus G* measured at 100°C and at 1 Hz frequency of < 100 kPa, wherein the inner packaging is in direct contact with the optionally hydrogenated nitrile rubber and the outer packaging at least partly enclosesP11600130-W02

[0083] the inner packaging.

[0084] With this regard, especially the technical features as well as the advantages as described above with regard to the packaging arrangement may be reached.

[0085] Like stated above with regard to the packaging arrangement, the polymer which is filled into the inventive packaging arrangement comprises optionally hydrogenated nitrile rubber which might have a Mooney viscosity Mu of < 30 MU, and a molecular weight Mw of < 150 kg / mol. Next to the complex modulus, it becomes clear that especially such rubbers are very sticky, so that the advantages of the present invention are especially valuable when using such a polymer.

[0086] The present invention further relates to a method of packing a polymer, wherein the polymer comprises an optionally hydrogenated nitrile rubber, wherein the optionally hydrogenated nitrile rubber has a complex modulus G* measured at 100°C and at 1 Hz frequency of < 100 kPa and, wherein the method comprises the steps of:

[0087] i) Providing a packaging arrangement like described;

[0088] ii) Pouring the polymer into the inner packaging, wherein the polymer is in a fluid state, in particular wherein the polymer is in a molten state and has a temperature in the range of > 100°C;

[0089] iii) Closing the inner packaging to completely enclose the polymer; and

[0090] iv) Providing the outer packaging outside of the inner packaging, in particular wherein step iv) is performed before step ii).

[0091] This method thus defines packing the described (H)NBR rubber by using the packaging arrangement according to the present inveniton.

[0092] With tis regard, the polymer is poured into the inner packaging. This might be done as a so-called cold fill or even preferred as a warm-fill when the polymer is in a molten state. The polymer may then have a temperature in the range of > 100°C, showing the requirments of the inner packaging, which, however, may be fulfilled according to the present invention.

[0093] In order to allow a suitable filling of the packaging arrangement with the polymer, it may be preferred that the packaging arrangement comprises a filling opening which has a size of > 100 cm2. For example, in case the outer packaging comprises a cardboard, the fillingP11600130-W02

[0094] opening may have the same size as the base area of the cardboard in case it is not closed by folding.

[0095] Afterwards, the inner layer is closed in order to protect the polymer to maintain its value.

[0096] The outer packaging is provided outside the inner packaging in order to provide a stable and rigid outer layer. In other words, the outer packaging provides the desired stability and rigidity and may in particular be more mechanically stable and / or rigid compared to the inner packaging. With this regard, the filled inner packaging may for example be transferred into the outer packaging, or the inner packaging may be filled inside the outer packaging, which may be preferred.

[0097]

[0098] Parameter Measurements:

[0099] Release force:

[0100] The release force, also called peel force can be measured as follows. A double-sided adhesive tape was attached to a stainless-steel sheet and the used HNBR was attached to it by hot pressing. Then, the inner packaging was attached with its contact surface, and the layers were pressed together at room temperature (22°C). 25 mm wide strips were cut out. The strip was conditioned for 3 hours (temperature of 23°C ± 2°C, humidity of 50% ± 5% relative humidity (RH)) before the use of the Universal testing machine Instron 3343, 100 mm / min, 180°. The release force may preferably be determined by ASTM 1876.

[0101]

[0102] The softening point was tested according to ASTM D36 (Ring and Ball test). In particular, the following method was performed: The film samples were cut to 2.8 X 3.0 cm and fixed on the ring. A 3.5 g stainless steel ball was placed on the film while immersed into silicone oil. The temperatures was raised from 30°C to a maximum of 180°C according to the norm. The softening temperature was recorded as the temperature when the ball dropped through the film, or when the film severely distorted. The softening point is taken as a unique representation until which temperature the liner film can still hold the hot polymer content.P11600130-W02

[0103] modulus:

[0104] The complex modulus g*, also called complex shear modulus, is a property of polymer material, i.e. the optionally hydrogenated nitrile rubber when subjected to periodic stress. A explanation can be found in Gooch, J.W. (eds) Encyclopaedic Dictionary pf Polymers. Springer, New York, NY. ISBN 978-0-387-31021-3, 2007, page 215. It is the complex response of the material to an applied strain (or stress) and is, in simplistic terms, the vector sum of the storage (Elastic) G’ and loss (viscous) G” components. Is there a norm? (ASTM D7522, for example, is for asphalt mixtures. The complex modulus is to be measured according to ISO 6721, Part 10 Plastics — Determination of Dynamic Mechanical Properties, Part 10, Complex Shear Viscosity Using a Parallel-Plate Oscillatory Rheometer.

[0105] Molecular weight:

[0106] The molecular weights were determined in the form of the weight average molecular weight (Mw) by means of gel permeation chromatography (GPC) in accordance with DIN 55672-1 (part 1: tetrahydrofuran THF as solvent).

[0107] Curing state:

[0108] The state of cure of a silicone coating may be determined as follows: A 3 x 3 cm sample of the material was soaked into 5 ml of pure hexane for 48 h at 22°C. FT-IR was measured under the same conditions for a dimethyl silicone oil, for a solution of 0.05wt% dimethyl silicone oil in hexane and the hexane used for soaking the liner, Using the vsi-o peak at 799.2 cm-1. This peak represents a maximum of free silicone which might migrate from the release coating into the HNBR product. The more silione is found to be extracted in the decribed way the lower in the degree of cure. The degree of cure can then be guantified as the weight ratio between the amount of free silione oil found and the weight of the silicone coating layer from the surface area of the measurd sample and the thickness of the coating layer, taking the density of the silicone as 0.965 g / cm3.

[0109] Bending test:

[0110] The bending test for evaluating the rigidity of the material, such as of the outer package, follows ASTM D903-98(2017) at 180 degree after having determined that the release force of the polymer from the inner layer was low such as below 0.2 N / 25mm. Under this condition the tested sample will exibit a force for the 25 mm wide strip which represents the resistance to bending and thus the resistance against mechanical stress or abuse which may happen during storage or transport.P11600130-W02

[0111] Used Polymer to be packed:

[0112] A HNBR polymer was used having a RDB content below 0.9%, an acrylonitrile content of 34%, a molecular weight Mw as determined by GPC of 45 kg / mol. The Mooney value was below 30 MU and could not specifically be determined as the viscosity was too low. The sample was prepared from NBR as described in EP 2289623 and subsequent hydrogenation. The polymer was obtained from solution using a dry finishing method according to US 2014 / 0024784. It had a complex modulus g* of 32 kPa.

[0113] The stickiness of HNBR can be predicted by taking the complex modulus, G* at 100°C and 1 Hz of the HNBR grades as measured with DMTA (Mettler, sandwich samples, 100°C).

[0114] Material of packaging arrangement:

[0115] Material P1:

[0116] Outer packaging: Corrugated cardboard box with a bottom box and top lid. It comprises outer carton with a layer from 135 g / m2Kraft paper, a corrugated paper with 90 g / m2, fluted, and an inner layer of 1110 g / m2Kraft paper, according to the norm VDW 1.33 B-Welle, 1.5-1.9 mm thickness.

[0117] Inner packaging: The inner packaging was a siliconized paper of 144 g / m2weight solvent-free glued on the outer package. This paper has a silicone coating of at least 3.2 g / m2having a curing degree of 100%. The release force was specified as 0.1 N / 25 mm. This packaging was specified for heat resistance when filling of up to 190°C. As paper will not soften, the ring-and-ball test can be considered to be at least above 190°C.

[0118] Material P1-D:

[0119] A carton box as with material P1 was used but the glued release paper was replaced by a silicone release coating having a curing degree of 100 % directly on the inner side of the carton.

[0120] Material P2:

[0121] Outer packaging: Corrugated cardboard box with bottom and top, based on an outer layer of 135 g / m2Kraft liner, corrugated paper of 100 g / m2and an inner layer of 135 g / m2Kraft paper, according to norm VDW 1.33 B-Welle, 2.2-3 mm thickness.P11600130-W02

[0122] Inner packaging: The inner side of the outer packaging was solvent-free glued siliconized paper of 135 g / m2with a silicone coating having a curing degree of 100%. The release force was specified as 0.05 N / 25 mm. As paper will not melt the ring-and-ball test can be considered to be at least above 190°C.

[0123] Material P3:

[0124] A polyethyleneterephtalat (PET) film with was coated with a double sided release coating being made from silicone being fully cured. The mechanical properties were determined on 50 pm film samples with tensile strength of 138 MPa (vertical to extrusion), 200 MPa (parallel to extrusion), the tear strength values were 5.9 and 4.1 N / mm vertical and parallel, respectively. The melting temperature was 154°C (as measured by DSC). The softening point according to the ring-and-ball-test was above 180°C (limit of testing device). From the mechanicals of this liner material one can conclude that the strength and protective capabilities for the HNBR is excellent.

[0125] Material P4:

[0126] Oriented polypropylene release films with mono-axial and bi-axial orientation and a thickness of 80 pm. Samples were obtained with silicone being fully cured release coating on both, and one side. Both sides were used for peel tests. The silicone release coating was completely cured and had a thickness in the range of 10 pm.

[0127] Material P6:

[0128] LDPE film, thickness of 160 pm, formed as a bag. The softening point according to the ring-and-ball-test was 128°C. No release coating was applied.

[0129] Material P7:

[0130] Ethylene vinyl acetate (EVA) film, thickness of 80 pm. The softening point according to the ring-and-ball-test was 123°C. No release coating was applied.

[0131] Material P8:

[0132] HDPE film. The softening point according to the ring-and-ball-test was 134°C. A silicone release coating was applied which was completely cured.

[0133] Performed packaging examples:

[0134] Example 1-1:

[0135] Carton made from packaging material P1: HNBR 1 solution was run through a dryP11600130-W02

[0136] finishing device such as described in US 2014 / 0024784, cooled to 115°C with a heat exchanger and filled into the packaging arrangement. The peel forced were determined by cutting a strip from the carton and pulling it vertically off from the polymer. Further, the bending strength of the carton itself against pulling in 180° was determined to be 3.8 N / 25 mm. This value shows that the outer packaging and thus the carton is that the carton is strong enough for safe packaging.

[0137] The packaging was examined after opening and no leakage of products was observed. There was no remaining product on the packaging even at the inner contact surface of the packaging arrangement. By pulling the complete side of the carton down and lifting it away from the packaged HNBR block with a measured force the net peel of the liner side from the HNBR was estimated to be <0.2 N / 25mm.

[0138] Such a packaging arrangement 10 is shown in figure 1. The packaging arrangement 10 comprises an inner packaging 12 and an outer packaging 14. According to figure 1, the inner packaging 12 comprises a main layer 16 and a contact layer 18 being only schematically in part shown for coming into direct contact with the polymer 20 which shall be packed in the packaging arrangement 10.

[0139] The polymer 20 comprises an optionally hydrogenated nitrile rubber, wherein the optionally hydrogenated nitrile rubber has complex modulus G* measured at 100°C and at 1 Hz frequency of < 100 kPa.

[0140] Further and with regard to the inner packaging, the main layer 16 comprises a material having no softening point according to the ring-and-ball-test below 120°C and the contact layer has at least in the contact surface to the polymer a release force of the material to be packed of < 0,2 N / 25mm.

[0141] It can be seen that even after a hot fill of the packaging arrangement with the hot polymer, according to the invention, the polymer is hold safe within the outer packaging (position 22), whereas in case the parameters according to the invention, especially the softening point, are not met, the inner packaging 12 may be deformed an may be bulged out of the outer packaging 14 (position 24).

[0142] Figure 2 shows a specific embodiment of the packaging arrangement 10 of the present invention, wherein figure 2 shows the outer packaging 14.P11600130-W02

[0143] It is shown that the outer packaging 14 is foldable to a closed container with a storage volume. This is for example possible in case all showed lines are folding lines and the shown outer packaging 14 is formed from cardboard. The outer packaging 14, or the container, respectively, has a ground area 26 which is rectangular in shape, four side areas 28 and a top area 30 The top area 30 is divided by a cut 32 into two parts 36a, 36b of the top area 36. The parts 36a, 36b can be folded as shown by the arrows via folding lines 34 so that the top area 30 is opened. Accordingly, the whole top area 30 forms an opening for introducing the polymer 20 into the storage volume of the packaging arrangement 10 and for removing the polymer 20 from the storage volume of the packaging arrangement 10.

[0144]

[0145] HNBR-1 as used in example 1-1 was filled into the packaging arrangement having P2 at 115°C. After filling and suffcient cooling in both examples, the outer and inner corners were examined for any product that might have flown into the gaps or out of the box. The result was that no leakage of was observed. The release forced were determined by cutting a strip from the carton and pulling it vertically off from the polymer. The release force was dominated by the mechanical force to peeling the stiff carton layer in vertical direction while the release from the liner material itself was obviously easy and below 0.2 N / 25 mm.

[0146] Further, the bending strength of the carton itself against pulling in 180° was determined to be 2.8 N / 25 mm. This value shows that the outer packaging and thus the carton is that the carton is strong enough for safe packaging.

[0147] The release layer was analyzed for free silicone oil by treating with a few ml of hexane, collecting the hexane and analyzing of ATR FT-IR. Results show that no free silicon oil was found that othewise might impact the usage of HNBR.

[0148] Examples 1-1 and 1-2 show that a packaging arrangement comprising a release liner in an outer packaging give a 180° peel which represents the strength of the carton itself. It was found that a manual release with a pull geometry of around 90° was easy and low effort.

[0149]

[0150] A transparent release liner film based on PET with a silicone release coating (packagingP11600130-W02

[0151] material P3) was provided with a layer of HNBR by pressing the latter to the liner at specific temperatures (see table 2). It was shown to have a release force which is 0.027 N / 25 mm according to the above-described peel test. In this way a cold fill and a warm fill was simulated, including repetitions.

[0152] Example 2-2:

[0153] Example 2-1 was repeated by the press temperature was 100°C, representing a warm fill process. The release forces from examples 2-1 and 2-2, both with a respective repetition, were as shown in table 1:

[0154]

[0155] Table 1

[0156] It could be seen that both examples 2-1 and 2-2 showed a very low peel strength (release strength) and may also be used in an outer packaging as described above with regard to examples 1-1 and 1-2 according to the invention.

[0157] According to the above-examples, it is thus possible to package the HNBR with a carton box which can have both, either a separate release liner as inner packaging, or a glued-on liner on the carton.

[0158] Example 3-1 (comparison):

[0159] Material P1-D was pressed at RT and 100°C with HNBR 1 and the peel forces were determined after cooling. As material P1-D had no separate inner packaging, the peel force was estimated by slowly lifting off the side carton from the packaged material. Thus, the estimated range of peel forces was found to be around 0.1 to 0.3 N / 25mm.

[0160] The bending force of the carton itself was determined from packaging strips and was 21 N / 25mm which shows good strength for packaging purpose. As mentioned, P1-D does not have a separate inner packaging but a coated release layer on the inner paper layer of the carton. Thus, it could not be excluded that the packed HNBR flows out of the card box during warm filling.P11600130-W02

[0161] Example 3-2 (comparison):

[0162] The same material was used as in example 3-1, wherein card box was deliberately scratched with a knife and the peel test was repeated on the area where the damage was placed. In this case, it was observed that some HNBR polymer kept attached to the carton. Especially where the inner surface of carton coating had been scratched, fibers of the carton were pulled out and contaminated the packaged HNBR. An uneven peel was observed in the range of 2 to 4 N / 25mm, see table 2.

[0163]

[0164] Table 2

[0165] At the spots where the carton was damaged in example 3-2 the release force was so high so that there was a fiber pull out (failure location r: rubber, failure location c: card box). Typically, fiber pull-out happens at an adhesion level of above 10 N / 25 mm in peel tests (see for example, B. Zhao et.al. , 3(7) TAPPI Journal, July 2004).

[0166] Thus, the uneven peel with the damaged layer can be explained by the local loss of release coating. The trials demonstrates that the high adhesive strength of the HNBR on substrates without release liner, thus the positive effects of the present invention are surprisingly pronounced.

[0167] Example 4-1 (comparison):

[0168] HNBR-1 was warm filled into a film pouch-based on an LDPE film (material P6) with 160 pm thickness and a melting point as measured by DSC of 115°C without release coating. It was observed that the film lost its shape and partly degraded. After cooling, the product could not be completely separated from the film and the peel forces from the low Mw HNBR were found to be very high as shown in the table below. The softening point was at 100°C Therefore, this film was deemed not suitable for packaging according to the present invention.P11600130-W02

[0169] Example 4-2: (comparison):

[0170] HNBR 1 was pressed on a thin (80pm thickness) EVA film without release coating at 100°C and at 25°C, cooled down and after a dwell as in example 2-1, the peel force was determined. Per DSC a melting point of 107°C was found. The softening point was around 123°C. It was found that a warm filling at 100°C would not be possible with such a film due to deformation and melting. The peel force to the low Mw HNBR was too high and the film was damaged due to stretching during the peel test. The peel force is shown in the table below. Therefore, this film was deemed not suitable for packaging due to insufficient strength and to high adhesion to HNBR.

[0171] Table 3 gives the data when HNBR-1 was pressed on a stainless-steel coupon with the thickness as indicated (rubber thickness), then the films (LDPE (material P7), EVA (material P8)) were pressed on the rubber side with the temperature as indicated. The peel strength values for LDPE and EVA were much too high to allow the removal of the product from the film without damaging the film. The examples 4-1 and 4-2 show that even with a release coating the LDPE and the EVA films would not allow a warm fill of low Mw HNBR due to heat induced damage of the films from too low softening points and further the release forces are far too high.

[0172]

[0173] Table 3

[0174] Example 4-3:

[0175] HNBR-1 was pressed on PP-type material P4 which was a thin (80pm) iPP film with silicone release coating at 100°C and at 25°C. Hot fill capability was tested by determination of the softening point (steel ball method):

[0176] MO-PP (monoaxially oriented PP): the softening point was remeasured between 150-155°C (Example 4-3-1). Example 4-3-1 gives the peel values with monoaxial MO-PP. For the MO-PP the peel force was 0.03 N / 25mm.

[0177] C-PP (biaxially oriented PP): the softening point was remeasured between 145-150°CP11600130-W02

[0178] (Example 4-3-2). Example 4-3-2 gives the peel values with biaxial C-PP. For the biaxial PP the peel force was 0.01 N / 25mm.

[0179] From that it is concluded that the upper filling temperature is between 145 and 155°C, depending on the type of PP film. Allowing a hot filling and allowing these examples being suitable as inner packaging according to the invention.

[0180]

[0181] HNBR-1 was pressed on a thin 80pm iPP film without silicone release coating at 100°C and at 25°C. The peels strength was 7.3 N / 25mm for both temperatures and deemed to be too high due to the lack of a release coating. The softening point was measured to be 145-150°C.

[0182]

[0183] HNBR-1 was pressed on an 80 pm thin HDPE film with silicone release coating having a curing degree of 100% at 100°C and at 25°C. The softening point was 134°C. The peel force was around 0.1 N / 25 mm.

[0184]

[0185] As with example 2-1 but a silicone oil layer was applied, in addition the surface angle of water on the released HNBR was determined. The peel force was below 0.01 N / 25mm. However, an increase surface angle on the contacted HNBR of 135°C indicated contamination of the packaged product.

[0186] A summary of the performed examples can be found in table 4:P11600130-W02

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[0194]

[0195] Table 4

[0196] The above examples show that a packaging arrangement according to the present invention allows a specific optionally hydrogenated (H)NBR, i.e.one with a high stickiness as defined by a complex modulus G* measured at 100°C and at 1 Hz frequency of < 100 kPa, to be securely packed and unpacked, either in hot or cold condition such as up to 145°C or even higher, thereby reducing the risk of contaminations of the polymer and thus maintaining itsP11600130-W02

[0197] value. The inner packaging will adopt the product temperature and then cool towards ambient temperature in the course of several hours, depending on the size of the packaging unit and how dense the packaging units are stacked. While some softening of the inner liner is permissible as the outer packaging will provide mechanical support a heat related distortion, melting, severe shrinking or other substantial dimensional damage of the inner packaging is securely avoided to protect the packaged (H)NBR.

[0198] From the examples it becomes clear that a silicone-based contact layer, also called release layer, coated on a release liner gives an excellent release performance, provided that the degree of cure of the said release layer is above 75% to ensure that the HNBR will not be contaminated by the packaging materials release coating.

Claims

P11600130-W02Claims1. A packaging arrangement (10) for enclosing and storing a polymer (20), wherein the polymer comprises an optionally hydrogenated nitrile rubber, wherein the optionally hydrogenated nitrile rubber has complex modulus G* measured at 100°C and at 1 Hz frequency of < 100 kPa, whereinthe packaging arrangement (10) comprisesan inner packaging (12) andan outer packaging (14), whereinthe inner packaging (12) comprises a contact layer (18) for coming into direct contact with the polymer (20) and optionally a main layer (16), whereinthe outer packaging (14) at least partly encloses the inner packaging (12) and wherein the outer packaging (14) is formed from paper, preferably from cardboard, and wherein at least the main layer (16) of the inner packaging (12), if provided, has no softening point according to the ring-and-ball-test below 120°C, and the contact layer (18) has a release force of the material to be packed of < 0,2 N / 25mm.

2. The packaging arrangement according to claim 1, wherein the outer packaging (14) is foldable to a closed container with a storage volume, wherein the container has a ground area (26), at least one side area (28) and a top area (30), wherein the container can be opened and closed by folding the top area (30).

3. The packaging arrangement (10) according to any of the preceding claims, wherein the packaging arrangement (10) has an opening for introducing the polymer (20) into the storage volume of the packaging arrangement (10) and for removing the polymer (20) from the storage volume of the packaging arrangement (10), the opening having a size of > 100 cm2.

4. The packaging arrangement (10) according to any of the preceding claims, wherein the inner packaging (12) comprises a main layer (16) being coated with a contact layer (18).

5. The packaging arrangement (10) according to claim 4, wherein the main layer (16) of the inner packaging (12) comprises a material selected from the group consisting of polypropylene; polyethylene; polyester; polyamide; polystyrene; or paper.

6. The packaging arrangement (10) according to any of the preceding claims, wherein the contact layer (18) comprises silicon having a curing degree of > 75%.P11600130-W027. The packaging arrangement (10) according to any of any of the preceding claims, wherein the inner packaging (12) and the outer packaging (14) are arranged as separate parts.

8. The packaging arrangement (10) according to any of the preceding claims, wherein the inner packaging (12) is fixed to the outer packaging (14).

9. The packaging arrangement (10) according to any of any of the preceding claims, wherein the main layer (16) of the inner packaging (12) has a melting temperature ora glass transition temperature in the range of > 120°C.

10. The packaging arrangement (10) according to any of the preceding claims, wherein the inner packaging (12) comprises a main layer (16) comprising paper, a contact layer (18) comprising silicon having a curing degree of > 75%, and wherein the outer packaging (14) comprises cardboard.

11. An arrangement comprising the packaging arrangement (10) according to any of the preceding claims and an optionally hydrogenated nitrile rubber, wherein the packaging arrangement (10) is filled with the optionally hydrogenated nitrile rubber such, that the optionally hydrogenated nitrile rubber is in contact with the inner packaging (12), wherein the optionally hydrogenated nitrile rubber has a complex modulus G* measured at 100°C and at 1 Hz frequency of < 100 kPa, wherein the inner packaging (12) is in direct contact with the optionally hydrogenated nitrile rubber and the outer packaging (14) at least partly encloses the inner packaging (12).

12. The arrangement according to claim 9, wherein the optionally hydrogenated nitrile rubber has a Mooney viscosity Mu of < 30 MU.

13. A method of packing a polymer (20), wherein the polymer (20) comprises an optionally hydrogenated nitrile rubber, wherein the optionally hydrogenated nitrile rubber has a complex modulus G* measured at 100°C and at 1 Hz frequency of < 100 kPa and, wherein the method comprises the steps of:i) Providing a packaging arrangement (10) according to any of claims 1 to 10;ii) Pouring the polymer (20) into the inner packaging (12), wherein the polymer (20) isP11600130-W02in a fluid state;iii) Closing the inner packaging (12) to completely enclose the polymer (20); and iv) Providing the outer packaging (14) outside of the inner packaging (12).

14. The method according to claim 13, wherein at step ii) the polymer (20) is in a molten state and has a temperature in the range of > 100°C.

15. The method according to claim any of claims 12 to 14, wherein the optionally hydrogenated nitrile rubber has at least one of a Mooney viscosity Mu of < 30 MU, and a molecular weight Mw of < 150 kg / mol.

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