Container for transporting and storing liquid compositions

Abstract

Containers useful for safely storing and transporting flammable, combustible, exothermic, explosive, and / or otherwise hazardous compositions, such as liquid organic peroxide-containing compositions, are provided. The containers include containment vessels with walls containing a thermosetting polymer and a vent mechanism. The containment vessels can be manufactured by a rotational molding process using a thermoplastic polymer, such as polyethylene, which is crosslinked to form a thermosetting polymer.

Description

[Technical Field]

[0001] The present invention relates to containers, more particularly composite intermediate bulk containers, adapted to hold liquid compositions, particularly flammable or combustible liquid compositions or liquid compositions containing compounds, such as organic peroxides, that are prone to exothermic decomposition. The containers of the present invention exhibit improved safety characteristics compared to conventional plastic composite intermediate bulk containers, in that they are able to withstand a fire environment for a specified period of time and under specified conditions without failure. The present invention also provides a method for making such an improved container. [Background technology]

[0002] Plastic composite intermediate bulk containers have been widely used in industry for many years to store and transport various types of liquid compositions. Intermediate bulk containers (commonly referred to as IBCs) typically have a capacity of approximately 1000 or 1250 liters and are convenient for use when the amount of composition to be stored and / or transported is too large to fit into a 55-gallon drum, but too small to fill a railroad tank car or tank truck. Plastic composite IBCs have a containment vessel constructed of a thermoplastic polymer, such as polyethylene, secured to a pallet or housed in a protective cage integral with the pallet. While thermoplastic polymers with satisfactory chemical and solvent resistance are available, such polymers readily soften and melt when the plastic composite IBC is exposed to high heat conditions (such as those encountered in a fire). Under such conditions, the plastic containment vessel may lose its structural integrity, causing its contents to be released.

[0003] Several approaches to imparting fire resistance to plastic composite IBCs have been described in the patent literature, with several patents (DE 102015012163 A, EP 0986421 A1, EP 2979991 A1, KR 20170033332 A, KR 20180056711 A, and U.S. Pat. No. 5,921,420) focusing on the use of a fire-resistant cladding that completely surrounds the IBC and provides fire insulation. Other approaches, described in U.S. Patent Nos. 5,924,589, 5,984,126, U.S. Patent Application Publication No. 2016 / 0289566A1, and U.S. Patent No. 7,828,995B2, involve incorporating fire-retardant additives into the plastic or painting the plastic with an intumescent coating that forms an insulating layer around the IBC in the event of a fire. A third approach, described in U.S. Patent No. 9,738,441B2, uses a built-in secondary enclosure to protect the IBC from damage caused by fire and mechanical handling equipment such as forklifts.

[0004] Containers particularly suited for packaging compounds, such as organic peroxides, that may undergo exothermic decomposition are also known in the art. For example, U.S. Patent No. 8,783,503 describes a packaged formulation containing a compound susceptible to exothermic decomposition and, optionally, one or more organic diluents, packaged in a container having a volume of at least 250 liters, equipped with a vent for releasing gas, and made of a thermoplastic material having a Vicat B softening temperature no higher than (a) the outlet temperature of the compound susceptible to exothermic decomposition, if the formulation does not contain any diluents, or (b) the boiling temperature of at least 50% by weight of the diluent, if the formulation contains an organic diluent. However, such packaging is less than ideal because, in the event of a fire, if the temperature and time are sufficient to melt the thermoplastic material, the entire contents of the container may be released. Another approach is described in U.S. Patent Application Publication No. 2012 / 0184685, which discloses stainless steel IBCs designed to contain liquid peroxide formulations and have a minimal vent area / volume ratio. However, such stainless steel IBCs have certain drawbacks. They are relatively heavy, which increases shipping costs and makes them more difficult to move around on-site. Furthermore, such stainless steel IBCs are opaque, making it difficult to determine the liquid level within them. Furthermore, this type of IBC is relatively expensive.

[0005] U.S. Patent No. 4,857,257 and U.S. Patent Application Publication No. 2017 / 0247534 describe the production of crosslinked rotomolded tanks using high-density polyethylene (HDPE) homopolymer, linear low-density polyethylene (LLDPE), and polyethylene copolymers containing various alpha-olefin monomers. U.S. Patent No. 5,260,381 discloses a similar approach for making rotomolded, crosslinked tanks containing small amounts of ethylene vinyl acetate (EVA) polymer. U.S. Patent No. 8,911,842 teaches a three-layer tank including an inner, non-crosslinked barrier layer encapsulated between two crosslinked layers. Summary of the Invention [Problem to be solved by the invention]

[0006] It would be desirable to develop new types of containers that are useful for storing and transporting flammable, combustible, or otherwise hazardous liquids and that can meet more stringent guidelines, such as those set forth in the 2018 edition of NFPA (National Fire Protection Association) Code 30. The present invention is directed to a thermosetting intermediate bulk container (IBC) that can withstand a flame environment for 20 minutes without failure, according to the test method set forth in FM 6020 (Approval Standard for Composite Intermediate Bulk Containers). [Means for solving the problem]

[0007] In certain embodiments, the present invention provides a container useful for storing and transporting compositions (e.g., liquid compositions containing at least one compound that is flammable, combustible, explosive, or capable of exothermic decomposition, or otherwise hazardous), the container comprising a containment vessel equipped with a vent mechanism and containing a thermosetting polymer.

[0008] In another aspect of the present invention, a packaged composition is provided that includes a container and a liquid composition packaged within the container (particularly a liquid composition containing at least one compound that is at least one of flammable, combustible, explosive, capable of exothermic decomposition, or otherwise hazardous), wherein the container includes a containment vessel equipped with a vent mechanism and containing a thermosetting polymer.

[0009] Also provided by aspects of the present invention is a method of making a container including a containment vessel equipped with a vent mechanism and containing a thermosetting polymer, the method including forming the containment vessel by rotational molding, blow molding, or three-dimensional printing.

[0010] In yet a further aspect of the present invention, a method of packaging a liquid composition (e.g., a liquid composition containing at least one compound that is at least one of flammable, combustible, susceptible to exothermic decomposition, explosive, or otherwise hazardous) is provided, the method comprising introducing the composition into a container equipped with a vent mechanism and including a containment vessel containing a thermosetting polymer.

[0011] The invention will be understood from the following description when read in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a rheograph showing crosslinking versus time for various amounts / loading levels of organic peroxide (including no peroxide) for crosslinking / curing HDPE. [Figure 2] FIG. 1 is a rheograph showing crosslinking versus time for various amounts / loading levels of organic peroxide (including no peroxide) for crosslinking / curing HDPE. DETAILED DESCRIPTION OF THE INVENTION

[0013] A container according to the present invention includes a containment vessel containing a thermosetting polymer and additionally has a vent mechanism that allows excess pressure within the containment vessel to be released when the contents of the containment vessel are exposed to heat and / or undergo decomposition to generate volatile decomposition reaction products.

[0014] In a preferred embodiment of the present invention, the container is a 1000-liter or 1250-liter intermediate product container configured to withstand 20 minutes of fire exposure without failure or leakage, as tested in accordance with Test Procedure Class Number 6020, Large Scale Testing for Fire Performance of Intermediate Bulk Containers (FM Approvals LLC, September 2016). This Test Procedure is cited in the National Fire Protection Association Flammable and Combustible Liquids NFPA Code 30 (2018) guidelines. The large-scale fire exposure test involves a 2 x 2 x 2 palletized array of eight 1000-liter or 1250-liter intermediate product containers filled with mineral seal oil, exposed to a pool of mineral seal oil flame for 20 minutes. The test array is centered under four sprinklers spaced on a 3.0 x 3.0 m grid. To pass this test, the intermediate product container must not break or leak during the 20-minute exposure period or for 24 hours after the test is completed. Formation of a hole above the liquid level in the intermediate product container must be no greater than 13 cm2 in net area. 2 If it does not exceed this, it is acceptable.

[0015] To provide a container that is fire-resistant and capable of safely storing and transporting compositions containing flammable, combustible, explosive, or exothermic compounds, the containment container used as a component of the container contains a thermosetting polymer. The term "thermosetting polymer" should generally be understood to mean a polymer that does not melt when heated, in contrast to a thermoplastic polymer. In the context of the present invention, a thermosetting polymer is a polymer that is sufficiently resistant to melting such that, when a containment container having a capacity of 1000 liters or 1250 liters and a wall containing the polymer is employed as an intermediate product container, the resulting intermediate product container can withstand a flaming environment for 20 minutes without failure or leakage, according to the test method described in Test Procedure Class Number 6020, Large Scale Testing for Fire Performance of Intermediate Bulk Containers (FM Approvals LLC, September 2016). In various embodiments, the containment vessel wall contains, consists essentially of, or consists of a thermosetting polymer, i.e., the containment vessel has a wall that includes a thermosetting polymer, which may or may not include one or more additional materials other than a thermosetting polymer according to various specific embodiments of the present invention.

[0016] Thermosetting polymers are polymers that resist melting and molding, in contrast to thermoplastic polymers, which are polymers that will soften or melt when repeatedly heated and harden when cooled. Typically, thermosetting polymers are materials that undergo a molecular crosslinking process that is irreversible and renders the material infusible. The crosslinking occurs through reactions between polymer chains, resulting in the formation of a three-dimensional network structure. In certain embodiments of the present invention, the thermosetting polymer on the containment vessel wall is produced by curing a thermosetting (heat-curable) resin composition, such as an epoxy resin composition, a melamine resin composition, a phenolic resin composition, a thermosetting vinyl ester resin composition, a thermosetting polyester resin composition, or a thermosetting polyurethane or polyurea resin composition. However, in preferred embodiments of the present invention, the thermosetting polymer is a crosslinked thermoplastic polymer, i.e., a thermoplastic polymer that has been converted to a thermoset polymer by imparting a sufficiently high level of crosslinking to the thermoplastic polymer (the crosslink density achieved is effective to convert the thermoplastic polymer to a thermoset polymer). In one preferred embodiment, the crosslinked thermoplastic is crosslinked chlorinated polyethylene, known as XL-CPE, having a chlorine content in the range of about 34% to 37%.

[0017] Before crosslinking the thermoplastic polymer (e.g., CPE), various additives known in the art can be added to further improve the flame retardancy of the IBC, if desired. Mineral compounds such as aluminum hydroxide and magnesium hydroxide can also be used as flame retardants in the present invention. Phosphorus flame retardants, including phosphate ester compounds, are non-halogenated compounds that act on the solid phase of combustible materials. Other flame-retardant plastic additives include brominated flame retardant (BRF) types. These additives can be used alone or in combination to improve flame retardancy. Specifically, brominated compounds, chlorinated compounds, brominated polymers, or chlorinated polymers are often used synergistically with antimony trioxide. This combination acts as a catalyst to increase the rate of release of bromine and chlorine radicals during gas-phase radical quenching.

[0018] Organic peroxides, particularly dialkyl-type peroxides, are preferably used to manufacture containment containers for IBCs containing crosslinked (thermoset) thermoplastic polymers by the rotomolding process. To obtain the minimum amount of crosslinking necessary to render the thermoplastic polymer thermoset in nature, the concentration of the dialkyl peroxide (when the thermoplastic polymer is polyethylene) should be at least 0.2 phr (parts by weight of peroxide per 100 parts by weight of resin). The range of peroxide used can be from 0.2 phr to 4.0 phr, preferably from 0.25 phr to 3.0 phr, more preferably from 0.3 phr to 2.0 phr, even more preferably from 0.4 phr to 1.5 phr, and even more preferably from 0.4 phr to 1.0 phr. Preferably, a triallyl-type crosslinking coagent (e.g., triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, diaryl itaconate, diallyl phthalate, or triallyl phosphate, which may be present in combination), is also used with the peroxide at a level of 0.2 phr to 3.0 phr, preferably 0.3 phr to 2.0 phr, more preferably 0.4 phr to 1.0 phr.

[0019] Thus, in a preferred embodiment of the present invention, the thermosetting polymer is a crosslinked thermoplastic polymer, particularly a thermoplastic resin crosslinked to a level sufficient to convert the thermoplastic polymer into a thermosetting polymer. In a preferred embodiment of the present invention, the thermoplastic polymer is first molded into a containment precursor structure having substantially the same size and shape as the desired containment, and then the thermoplastic polymer in the precursor structure is crosslinked to a thermosetting polymer to obtain a containment suitable for use in the container of the present invention. Suitable molding methods include, for example, blow molding, rotational molding, and three-dimensional printing. In another preferred method, the thermoplastic polymer is molded and crosslinked simultaneously, or in an overlapping manner (where molding and crosslinking occur simultaneously to some extent; for example, crosslinking does not occur during the early stages of molding the thermoplastic polymer into the containment, but crosslinking begins later in the molding stage).

[0020] The degree of crosslinking in thermoplastic polymers used to construct containment vessels according to the present invention can be monitored, for example, by subjecting a sample of the crosslinked thermoplastic polymer to a xylene dissolution test according to ASTM D-1998-06(2006). In this test, a sample, a piece of crosslinked thermoplastic polymer, is first removed from the containment vessel. The sample is then weighed. The sample is then boiled in xylene. The sample is then reweighed, and its % weight retention is calculated using the following formula: (sample weight after boiling) ÷ (initial sample weight) × 100. The higher the % weight retention, the higher the degree of crosslinking. In various embodiments of the present invention, the thermoset polymer obtained by crosslinking the thermoplastic polymer utilized in the containment vessel has a weight retention, measured according to ASTM D-1998-06(2006), of at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 99%, or even 100%.

[0021] Other methods exist that use instruments (i.e., rheometers) to determine the relative degree of crosslinking according to standardized test procedures: ASTM D-5289, ASTM D-5992, and ASTM D-6601 rotorless rheometer (also known as moving die rheometer, or MDR or RPA instrument), which are used to measure the amount of crosslinking and, in the practice of the present invention, can determine the degree of crosslinking based on torque values in dN·m.

[0022] Of particular importance for IBCs made from crosslinked materials for transporting organic peroxides is the relationship of the crosslinked material's modulus G' response to temperature, particularly at the critical SADT (self-accelerating decomposition temperature) (and above), where G' intercepts. These G' measurements are performed using a TA Instruments RSA3 Dynamic Mechanical Analyzer (strain control) and / or a TA Instruments RSA-G2 Solid Analyzer (strain control), and / or an Anton Paar MCR502 Rheometer (stress control), using the procedures and calculations described in ASTM D4065-12 (Standard Practice for Plastics: Dynamic Mechanical Properties: Determination and Report of Procedures). At and above the "SADT" and / or "runaway" temperature, organic peroxides undergo uncontrolled self-accelerating decomposition, generating heat and flammable gases. The relationship between G' and SADT temperature (critical temperature) is important when designing crosslinked containment for IBCs with the goal of maintaining containment integrity at or above the "SADT" and / or "flow" temperatures. In summary, it is particularly advantageous to design IBC containment made from crosslinked thermoplastic materials to have a rubbery plateau (a region in which the modulus G' is effectively constant as a function of temperatures above the glass transition temperature (Tg), the SADT of the stored material, and above). Non-crosslinked thermoplastic materials would not exhibit such properties in their DMA.

[0023] In various embodiments of the present invention, the thermoset polymer obtained by crosslinking a thermoplastic polymer and used in the containment vessel has a torque value measured using a moving die rheometer under test conditions of 190°C, 100 cpm, and 1 degree arc per ASTM D-5289-95 (Reapproved, 2001) of at least 7 dN·m, at least 8 dN·m, at least 9 dN·m, at least 10 dN·m, at least 15 dN·m, at least 20 dN·m, at least 25 dN·m, at least 30 dN·m, at least 35 dN·m, at least 40 dN·m, at least 45 dN·m, or at least 50 dN·m.

[0024] The use of cross-linked thermoplastic polymers as thermosetting polymers used to construct containment walls can offer several advantages. Many thermoplastic polymers, such as high-density polyethylene (HDPE), are nearly translucent. However, when highly cross-linked, such thermoplastic polymers can be made to have much greater transparency. This is especially true if the cross-linking reaction is carried out at a sufficiently high temperature (e.g., approximately 190°C for HDPE). By using a more highly cross-linked thermoplastic polymer to construct the containment walls, the liquid level within the containment can be more easily monitored (i.e., the transparent walls allow for a rapid visual assessment of the liquid level within the containment).

[0025] An additional advantage is that crosslinking can improve the impact resistance of the containment container compared to containment containers molded from non-crosslinked thermoplastic polymers. For example, non-crosslinked HDPE, which is typically recommended and used for storing certain organic peroxides, can be brittle, especially at low temperatures. Containment containers made from non-crosslinked thermoplastic polymers, such as HDPE, can crack even when subjected to relatively minor mechanical shocks during handling, which can compromise the integrity of the containment container and result in leakage of its contents. Therefore, crosslinking a thermoplastic polymer, such as HDPE, can result in a container with improved low-temperature impact resistance.

[0026] The impact resistance of crosslinked thermoplastic materials is measured using a Fractovis (Ceast / Instron) high-speed instrumented impact tester. The purpose of this high-speed impact test is to measure the toughness, load-deflection curve, and total energy absorption from an impact event of the crosslinked thermoplastic material used to construct the containment for the IBC. The variable speed allows for simulating real impact values at high speeds (e.g., impacts from the metal forks of a forklift truck). This sophisticated impact test provides the total force-energy content and energy curve during millisecond impacts using a drop hammer (tup) containing an impact head and load cell. The Fractovis impact tester was designed and built to meet the needs of the plastics industry in accordance with the following ASTM test methods: ASTM D3763-15 (High Speed Puncture Properties of Plastics Using Load and Displacement Sensors), as well as other methods such as ASTM D5628-96 (Impact Resistance of Flat, Rigid Plastic Specimens by Means of Falling Dart (Tup or Falling Mass)).

[0027] Yet another significant advantage provided by at least some embodiments of the present invention is that crosslinking can improve the flexibility of the thermoplastic polymer. That is, the walls of a containment vessel comprising a crosslinked thermoplastic polymer can be made more flexible than the flexibility of a containment vessel comprising a similar, uncrosslinked form of the thermoplastic polymer. For example, fully crosslinked polyethylene can be considered an elastomer. Thus, a containment vessel made of such crosslinked polyethylene can be significantly more easily collapsed (when no liquid is present within the containment vessel) than a containment vessel having walls made of non-crosslinked polyethylene. A more easily collapsed containment vessel can be advantageous for storage and disposal when the containment vessel is empty, and further, the level of liquid remaining in the containment vessel can be more easily monitored when aliquots are dispensed.

[0028] Although preferred embodiments of the present invention utilize crosslinked polyethylene, other suitable crosslinked thermoplastic polymers include, for example, other types of polyolefins and copolymers of olefins with other types of monomers. The starting thermoplastic polyethylene can be any of the various ethylene homopolymers and copolymers known in the art. Suitable ethylene copolymers include copolymers in which ethylene accounts for at least 60%, at least 70%, at least 80%, or at least 90% by weight of the repeat units in the copolymer, with the balance being one or more comonomers, such as an olefin, particularly a C3-C10 alpha-olefin, and / or vinyl acetate.

[0029] Cross-linked high density polyethylene (HDPE) is particularly preferred when the composition packaged in the container contains flammable and combustible liquids and / or organic peroxides, because it is generally not degraded by such materials and is chemically compatible with organic peroxides under normal storage conditions (e.g., temperatures up to about 40°C).

[0030] Also suitable for use are ethylene homopolymers and copolymers that have been modified after polymerization, for example, by chlorination. Thus, in certain embodiments of the present invention, the starting thermoplastic polyethylene comprises at least a chlorinated polyethylene. In one embodiment, a blend of at least one chlorinated polyethylene and at least one non-chlorinated polyethylene (e.g., high-density polyethylene) is employed. More generally, a blend of two or more different crosslinked thermoplastic polymers could be used. For example, two or more thermoplastic polymers could be blended together and then crosslinked to obtain a thermoset polymer.

[0031] Crosslinking of thermoplastic polymers can be accomplished by any suitable means known in the art, provided that the method or methods employed achieve a degree of crosslinking sufficient to convert the original thermoplastic polymer into a thermoset polymer. For example, both chemical and physical crosslinking methods can be employed. One such method involves reacting the thermoplastic polymer with one or more organic peroxides, optionally with one or more coagents. This approach typically results in the formation of carbon-carbon bonds between polymer chains. Suitable organic peroxides include dialkyl peroxides, alkylaryl peroxides, diacyl peroxides, organic hydroperoxides, peroxyesters, peroxyketals, ketone peroxides, and monoperoxycarbonates, such as 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3; p-di-t-butylperoxy(di-isopropyl)benzene; m-di-t-butylperoxy(di-isopropyl)benzene; isopropenyl-t-butylcumylperoxy peroxide; 1-(2-t-butylperoxyisopropyl)-3-isopropenylbenzene; t-butylcumyl peroxide; 2,5-dimethyl-2,5-di(t-butylperoxy)hexane; dicumyl peroxide; di-t-butyl peroxide; di-t-amyl peroxide; n-butyl-4,4-bis(t-butylperoxy)valerate; 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane; Trigonox® 301; Trigonox® 311; and combinations thereof. Preferred organic peroxides are those having a half-life of 1 hour at temperatures above 99°C. In a preferred embodiment of the present invention, an amount of organic peroxide between 0.5% and 3% by weight of the thermoplastic polymer is employed to achieve a relatively high degree of crosslinking.Suitable coagents include, for example, those containing two or more reactive carbon-carbon double bonds per molecule (e.g., those present in allyl, vinyl aromatic, and (meth)acrylate functional groups), such as triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, diaryl itaconate, diallyl phthalate, triallyl phosphate, and combinations thereof. Another suitable coagent is alpha-methylstyrene dimer (2,3-diphenyl-4-methyl-1-pentene), sold under the brand name Nofmer® MSD, which can be used alone or in combination with the allyl-functional species listed above. In a preferred embodiment of the present invention, the amount of coagent used is equivalent to the amount of organic peroxide, e.g., 0.5% to 6% by weight of the thermoplastic polymer. Other components that may be present during crosslinking include hydroquinones such as mono-t-butylhydroquinone (MTBHQ) and HQMME (hydroquinone monomethyl ether), peroxide scavengers (to prevent premature crosslinking) such as 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl (abbreviated 4-OH-TEMPO), and / or antioxidants (including hindered phenols and thio-based antioxidants). It is also possible to use free radical polymerization initiators other than organic peroxides to effect crosslinking of thermoplastic polymers.

[0032] Another suitable method is moisture curing of a thermoplastic polymer, where the thermoplastic polymer contains silane groups that enable crosslinking. Heat and / or silanol condensation catalysts may be employed to accelerate the crosslinking rate. Silane-functionalized thermoplastic polymers, including silane-functionalized polyethylene, are well known in the art. Silane grafting can be used to introduce silane functional groups into a thermoplastic polymer. For example, vinyltrialkoxysilanes (including, for example, vinyltrimethoxysilane and vinyltriethoxysilane) can be grafted onto polyethylene chains by combining polyethylene with a vinyltrialkoxysilane and a free-radical polymerization initiator, such as an organic peroxide, and initiating a reaction between the polyethylene and the vinyltrialkoxysilane, resulting in a silane grafting reaction to form trialkoxysilane functional groups on the polymer chain. In the presence of water, the trialkoxysilane functional groups convert to silanol functional groups, which then condense with each other to form crosslinked siloxane bonds.

[0033] A further method uses radiation curing, in which a thermoplastic polymer is exposed to radiation, such as gamma or electron beam irradiation. As with peroxide-initiated crosslinking, the covalent crosslinks formed by radiation curing are typically carbon-carbon bonds between polymer chains.

[0034] In certain embodiments, the containment wall may have a single layer of a thermosetting polymer. In other embodiments, the containment wall may include two or more polymer layers, at least one of which is a thermosetting polymer. It is also possible for the containment wall to contain two or more different thermosetting polymer layers. For example, the containment wall may have an outer layer of cross-linked chlorinated polyethylene and an inner layer of cross-linked high-density polyethylene. As another example, the outer layer may be a cross-linked chlorinated polymer and the inner layer may be a blend of cross-linked high-density polyethylene and cross-linked chlorinated polyethylene.

[0035] In certain embodiments of the present invention, the containment vessel wall comprises at least one layer of at least one thermosetting polymer and at least one layer of at least one thermoplastic polymer. For example, the containment vessel wall may have a layer of thermoplastic polymer on the inside and a layer of thermosetting polymer (e.g., a fully crosslinked thermoplastic polymer) on the outside. In preferred embodiments of the present invention, heat-resistant engineering thermoplastics are employed to form the thermoplastic polymer layers. Examples of suitable heat resistant engineering thermoplastic polymers include, but are not limited to, fluoropolymers (e.g., fluoropolymers sold under the brand name Kynar® by Arkema), polyamides, polyaryletherketones (e.g., polyetherketone, polyetherketoneketone, polyetheretherketone, e.g., polyaryletherketone sold under the brand name Kepstan® by Arkema), polyethersulfones, polycarbonates, aromatic polyesters such as polyethylene terephthalate and polybutylene terephthalate, polysulfones, polyphenylene oxides, polyphenylene sulfines, polyimides, and polyacetals.

[0036] If the containment wall contains two or more polymer layers, one or more tie layers may be disposed between adjacent polymer layers to improve or enhance adhesion between the adjacent polymer layers. Any tie layer composition known in the art may be used for this purpose; such tie layer compositions are typically polymer-based but may contain one or more additional additives. The polymer or polymers used in the tie layer composition are preferably functionalized with reactive and / or polar functional groups, such as carboxylic acid groups, carboxylate groups, epoxy groups, hydroxyl groups, anhydride groups, and the like. Representative examples of polymers suitable for use in tie layer compositions include, but are not limited to, ethylene-vinyl acetate polymers, ethylene-methyl acrylate polymers, ethylene-butyl acrylate polymers, ethylene-acrylic acid polymers, ethylene-methacrylic acid polymers, maleic anhydride-grafted polyolefins, such as ethylene-grafted-maleic anhydride polymers (also known as anhydride-modified polyethylene), polyamides, fluoropolymers, and the like.

[0037] While a thermosetting polymer (or a blend of thermosetting polymers) alone may be used to provide the containment wall, certain embodiments employ one or more thermosetting polymers in combination with one or more additives. Such additives may be any additive known in the polymer art, including, for example, fillers, flame retardants, fire retardants, antioxidants, light stabilizers (including UV stabilizers and HALS hindered amine light stabilizers), internal and external mold release agents, and combinations thereof. Thus, the containment wall may comprise a thermosetting polymer composition containing at least one thermosetting polymer and at least one additive, as described above. In a further embodiment of the present invention, the containment wall includes a thermosetting polymer wall the exterior of which is coated with an intumescent layer or a layer of flame and / or fire retardant, which layer is effective to provide additional flame and / or fire resistance to the containment. However, in other embodiments, such intumescent layer, flame retardant layer / fire retardant layer is not present.

[0038] In certain preferred embodiments of the present invention, the thermosetting polymer employed to provide the containment wall is non-flammable. In the context of the present invention, the term "non-flammable" means that the thermosetting polymer will not ignite when exposed to an open flame or is self-extinguishing (i.e., the thermosetting polymer cannot sustain a flame even if ignited). For example, the thermosetting polymer has a UL 94 V rating of VO. In other embodiments, the thermosetting polymer has a Limiting Oxygen Index (LOI) of at least 30, at least 40, at least 50, or at least 60, as measured according to ASTM D2863-17a.

[0039] The containment vessel wall may have any desired or appropriate thickness, and the wall thickness may be constant or may vary from portion to portion of the containment vessel. For example, the containment vessel may have an average wall thickness of about 0.5 mm to about 125 mm.

[0040] The containment vessel may be of various shapes or sizes as appropriate or desired. For example, in various embodiments of the present invention, the containment vessel may be cubic, rectangular, or cylindrical. If the containment vessel is cubic or rectangular, the containment vessel may have four sides, a top, and a bottom, each of which is generally planar. If the containment vessel is cylindrical, the containment vessel may have a single curved side, a generally planar top, and a generally planar bottom. The walls may have folds, pleats, etc., to provide rigidity and / or collapsibility to the containment vessel. The containment vessel defines an interior volume of the containment vessel. The containment vessel may have an internal volume of, for example, at least 250 liters, at least 500 liters, or at least 750 liters, but may independently be up to 10,000 liters, up to 5000 liters, or up to 2500 liters. In certain embodiments, the containment vessel may have an internal volume of 500 liters to 3000 liters, 900 to 1500 liters, or about 1000 liters, or about 1250 liters.

[0041] The vessel includes at least one vent mechanism configured to allow venting of the contents of the containment vessel. The vent mechanism is adapted to temporarily open to release the internal pressure of the containment vessel and then close once the internal pressure returns below a predetermined level. Alternatively, the vent mechanism can be designed to remain open once a predetermined internal pressure is reached. The vent mechanism or mechanisms may be integral with the containment vessel (e.g., molded into or with the containment vessel when molding the containment vessel or its precursor structure), or alternatively, attached to or associated with the containment vessel after the containment vessel is assembled.

[0042] Types of vent mechanisms suitable for use in the present invention include, for example, rupture disks, pressure relief valves, pop-off caps, rupture bolts, spring-loaded clamp rings, pressure relief portions containing thermoplastic polymers that melt when heated, and pressure relief portions in the wall of a containment vessel that are sufficiently thinner than the remainder of the wall of the containment vessel to controllably release pressure within the containment vessel when internal pressure is applied to the containment vessel before the containment vessel reaches its burst pressure. The vessel may be equipped with more than one type of vent mechanism, and they may be of different types.

[0043] The container must be equipped with at least one vent mechanism or mechanisms to rapidly release at least a portion of the contents of the containment, avoiding an explosion, if a specified maximum pressure is exceeded. The required size of this opening (vent area) depends, for example, on the volume of the containment, the material from which the containment is made, and the type of liquid composition present in the containment. The minimum vent area required for a particular packaged formulation can be determined by the 10-liter venting test described in Amendment 1 to the 4th revision of the Manual of Test and Criteria ST / SG / AC.10 / 32 / Add.2 (February 23, 2005), Appendix 5 of the United Nations Recommendations on the Transport of Dangerous Goods.

[0044] The vent area / volume ratio of the vessel must be at least 20 x 10 -3 m 2 / m 3 , preferably at least 50 x 10 -3 m 2 / m 3 , more preferably at least 80×10 -3 m 2 / m 3 , and most preferably at least about 100×10 -3 m 2 / m 3 For practical reasons, the vent area / volume ratio is preferably 250×10 -3 m 2 / m 3 Less than or equal to 125 × 10 -3 m 2 / m 3 The following is the result.

[0045] The containment vessel may have one or more openings (which may or may not be independent of a vent mechanism) in its wall to allow a substance (e.g., a liquid) to be introduced into or withdrawn from the containment vessel. Any such openings are preferably configured so that they can be opened and closed for convenient filling, draining, and / or cleaning of the containment vessel.

[0046] In one embodiment of the invention, the containment vessel may have an opening (e.g., in the upper wall of the containment vessel) that functions as a fill port, allowing a liquid composition to be introduced into the containment vessel using a feed line (e.g., a hose, pipe, etc.) temporarily connected to the containment vessel for the purpose of filling the containment vessel. Once the containment vessel is filled to a desired level, the feed line is disconnected, and the opening (and the containment vessel generally) is sealed using a device that includes a vent mechanism. For example, the opening may be threaded so that the feed line and, in turn, a cap including a vent mechanism can be attached (e.g., the feed line is disconnected and then a cap with a vent mechanism is threaded onto the threaded opening). In another embodiment, the opening may be configured so that a dip tube can be inserted through the opening and connected to a pump or the like to withdraw the liquid composition present in the containment vessel from the containment vessel.

[0047] The containment vessel may additionally or alternatively include a dispensing tap located on the bottom of the containment vessel or on a side of the containment vessel near the bottom edge, the dispensing tap being configured to allow the liquid composition present in the containment vessel to be expelled or withdrawn from the interior of the containment vessel. The fill port and / or dispensing tap may also be used for flushing and / or cleaning the containment vessel, and are mounted so as to be reusable or refillable.

[0048] In certain embodiments, the containment vessel may be surrounded by a protective cage. The protective cage may be configured to protect the vessel from damage or destruction during use, storage, or transportation and / or to support the containment vessel (particularly if the containment vessel were to collapse or collapse without the protective cage). Various protective cage designs known in the art may be employed for use with the vessel of the present invention. For example, the protective cage may be a cylindrical metal cage, such as a cylindrical reinforced stainless steel or iron cage. The cage may also be composed of or consist of non-metallic materials, such as a single polymeric material or a combination of various polymeric materials (e.g., liquid thermoplastic resins sold by Arkema under the brand name Elium®).

[0049] The protective cage may include or have a pallet attached, for example, the bottom of the protective cage may be molded in the shape of a pallet, and the pallet (and thus the container with its containment and packaged contents) may be designed to be movable using a forklift or pallet jack. The containers of the present invention may be configured to be stackable.

[0050] In certain embodiments of the present invention, the containment may be configured to be self-supporting, i.e., to substantially retain its three-dimensional shape and not collapse or fold when the containment is empty. In such embodiments, the walls of the containment may be configured to have a sufficient thickness to impart self-supporting properties to the containment. The base of such a self-supporting containment may be made of a thermosetting polymer and may define an opening to receive the forks of a forklift or other such equipment, thereby eliminating the need for a separate pallet.

[0051] The containers of the present invention are particularly useful for packaging hazardous compositions, particularly hazardous liquid compositions. For example, the compositions to be packaged may be flammable, combustible, explosive, and / or prone to exothermic decomposition. Once packaged in the containers of the present invention, such compositions can be easily and conveniently transported, stored, and used, and the risk of the contents of the container leaking or the container exploding into pieces if the container is exposed to a fire or other high-heat condition is reduced. Compositions suitable for packaging in accordance with the present invention include compositions that are at least one of flammable, combustible, explosive, or exothermally decomposable, as well as compositions that include at least one compound that is at least one of flammable, combustible, explosive, or exothermally decomposable.

[0052] Compositions suitable for packaging in the containers of the present invention include, for example, flammable or combustible organic solvents, compositions containing at least one flammable or combustible organic solvent, and at least one component (other than the flammable or combustible organic solvent) dissolved or dispersed in the at least one flammable or combustible organic solvent. Peroxides, particularly organic peroxides, can also be packaged in the containers of the present invention. Such peroxides can be in neat or liquid form, or dissolved or dispersed in a liquid medium, such as an organic solvent or a mixture of organic solvents, or in the form of an aqueous emulsion. The organic peroxide or blend of organic peroxides can also contain one or more components other than the organic solvent and / or water, such as stabilizers and phlegmatizers. Various types of organic peroxides can be packaged in containers according to the present invention, including, for example, diacyl peroxides, peroxyesters, perketals, percarbonates, dialkyl peroxides, alkylaryl peroxides, monoperoxycarbonates, hydroperoxides, and the like, and combinations thereof.

[0053] The containment vessels used in the present invention can be made using any suitable method.

[0054] For example, one method for forming a containment vessel involves blow molding a thermoplastic polymer and then crosslinking it to convert it to a thermoset polymer. Methods for blow molding thermoplastic polymers, such as polyethylene, are well known in the art and can be readily adapted for use in the present invention. Generally, the blow molding process involves extruding a tube of molten thermoplastic polymer into a mold and then injecting compressed gas into the center of the tube, thereby forcing the thermoplastic polymer against the mold walls. In one method, a resin composition containing a thermoplastic polymer and at least one crosslinking additive (e.g., organic peroxide, allyl-containing coagent, and hydroquinone) is blown under conditions effective to crosslink the thermoplastic polymer during blow molding, and / or crosslinking is effected by heating the blown precursor structure after blow molding. Crosslinking of a thermoplastic polymer can be achieved by heating the thermoplastic polymer in the presence of an organic peroxide to a temperature effective to activate the organic peroxide (i.e., a temperature effective to generate free radical species from the organic peroxide, which then crosslink the thermoplastic polymer). Such high temperature heating can also be carried out while the precursor structure for containment is still in the mold.

[0055] In another embodiment, a silane-functionalized thermoplastic polymer is used to form a precursor structure (having approximately the same shape and dimensions as the desired containment vessel) for blow-molded containment, and then the blow-molded precursor structure is moisture-cured to convert it into the containment vessel, where the silane-functionalized thermoplastic polymer is crosslinked to form a thermoset polymer.

[0056] In yet a further embodiment, a thermoplastic polymer is used to create a blown-molded precursor structure which is then converted into a containment vessel containing a thermoset polymer by irradiating it, thereby crosslinking the thermoplastic polymer. The irradiation can be carried out using electron beam, gamma radiation, etc.

[0057] In another embodiment, a three-dimensional printing process is used to mold a thermoplastic polymer into a precursor structure for a containment vessel. The 3D-printed precursor structure is then converted into a containment vessel having walls comprising a thermosetting polymer by any suitable method. For example, the 3D-printed precursor structure may be irradiated using electron beam, gamma radiation, or the like under conditions effective to crosslink the thermoplastic polymer and form a thermosetting polymer. In yet another approach, a precursor structure is three-dimensionally printed using a silane-functionalized thermoplastic polymer, and then moisture-cured to yield a containment vessel comprising a thermosetting polymer. In yet another approach, a crosslinkable thermoplastic composition comprising a thermoplastic polymer and a free-radical polymerization initiator (e.g., an organic peroxide) is used to three-dimensionally print a precursor structure for a containment vessel, and then the precursor structure is heated at a temperature and for a time effective to achieve sufficient crosslinking of the thermoplastic polymer to achieve thermoset (melt-resistant) properties. Three-dimensional printing techniques employing thermoplastic polymers are known in the art, and any such technique, including selective laser sintering and fused filament fabrication, can be adapted for use in the present invention.

[0058] In one preferred embodiment, the containment container can be molded using a rotational molding process. Any rotational molding process known in the art can be adapted for use in the present invention. Typically, in rotational molding, a thermoplastic polymer in particulate form (e.g., powder or granule form) is placed into a hollow mold, which is then closed, rotated on two axes, and heated (possibly in a furnace) to fuse the thermoplastic polymer particles together and create a solid, hollow object inside the mold. The mold is then removed from the furnace and cooled with air or water spray. After cooling, the molded hollow part is removed, and the interior of the mold is filled with new thermoplastic polymer particles to begin another cycle. Descriptions of rotational molding processes involving thermoplastic polymers are found, for example, in the following patent documents, each of which is incorporated herein by reference for all purposes: U.S. Pat. No. 4,857,257; U.S. Pat. No. 5,260,381; U.S. Pat. No. 8,911,842; and U.S. Patent Application Publication No. 2017 / 0247534. It is understood that, in the present invention, those processes must be modified to convert thermoplastic polymers into thermosets.

[0059] In one embodiment of the present invention, particulates of a crosslinkable resin composition containing at least one thermoplastic polymer (e.g., at least one polyethylene), at least one free-radical polymerization initiator (e.g., at least one organic peroxide), and optionally (but preferably) at least one crosslinking coagent (e.g., at least one compound functionalized with multiple vinyl groups) are used in a rotational molding process to prepare a containment container having a wall of a thermosetting polymer (e.g., a crosslinked thermoplastic polymer, such as crosslinked polyethylene). Such particulates may have an average diameter of, for example, 50 to 500 microns and may be prepared by any suitable method. For example, a thermoplastic polymer may be compounded with a free-radical polymerization initiator and optionally other ingredients, and molded into pellets or granules, which are then crushed or ground and optionally sieved or subjected to other size classification methods to obtain the particulate crosslinkable resin composition. In another embodiment, a thermoplastic polymer (possibly in combination with one or more other additives) is molded into particles of the desired size, and the particles are impregnated with a free radical polymerization initiator (and possibly other additives, such as a crosslinking coagent), particularly a liquid free radical polymerization initiator or a solution of the free radical polymerization initiator in a suitable solvent or mixture of solvents. During such processing, care should be taken to minimize undesired reactions of the free radical polymerization initiator. If the free radical polymerization initiator is thermally activated, for example, the processing temperature should be kept below the temperature at which significant conversion of the free radical polymerization initiator to free radical species begins. This allows the thermoplastic (melt) properties of the thermoplastic polymer to be maintained, thereby enabling the crosslinkable resin composition particles to be satisfactorily rotomolded.

[0060] In certain embodiments of the present invention, particulates of a thermoplastic resin composition are introduced into a hollow mold, and the hollow mold containing the particulates is then rotated while being heated at a temperature effective to fuse the particulates together and form a precursor structure for the desired containment vessel. The temperature during this molding stage should be maintained below the temperature at which substantial crosslinking of the thermoplastic resin occurs, which would convert the thermoplastic polymer in the unmelted particulate state to a thermoset polymer and prevent satisfactory melting of the particulates. However, a relatively low level of crosslinking is acceptable, since even if some crosslinking occurs, the particulates retain a sufficient level of thermoplasticity and are meltable. The rotomolded precursor structure can then be processed into the desired containment vessel by heating the precursor structure to a temperature effective to obtain the desired level of crosslinking in the thermoplastic polymer (thereby converting the thermoplastic polymer in the rotomolded precursor structure to a thermoset polymer). Such heating can be carried out in the mold (e.g., the precursor structure is heated while remaining in the mold to a higher temperature effective to activate the free-radical polymerization initiator (e.g., an organic peroxide) and achieve the degree of crosslinking necessary to convert the thermoplastic polymer to a thermoset), and then the rotomolded containment container is removed from the mold. Preferably, the mold is still rotating during such additional heating to allow the containment container to retain the desired shape; that is, rotation of the filled mold continues while the containment container is heated at the activation temperature of the free-radical polymerization initiator, at least long enough for the walls of the containment container to acquire sufficient thermosetting properties so that the containment container does not distort when rotation is stopped. In another embodiment, the precursor structure to become the containment container is removed from the mold and subjected to further heating under conditions effective to crosslink the thermoplastic polymer to the desired level, thereby resulting in a containment container having thermoset polymer walls.

[0061] Rotational molding can also be used to form containment containers with multiple walls, at least one of which contains a thermosetting polymer. For example, an outer wall containing a thermosetting polymer (or a precursor to a thermosetting polymer, i.e., a crosslinkable thermoplastic polymer composition) is first molded in a mold using the method described above. Then, particles of a second polymer composition are introduced into the mold to form an inner wall. The second polymer composition can be another crosslinkable thermoplastic polymer composition (e.g., a composition containing a thermoplastic polymer, a free-radical polymerization initiator, and optionally a crosslinking coagent) or a non-crosslinkable thermoplastic composition (e.g., a composition containing a thermoplastic polymer but no free-radical polymerization initiator). The particles of the second polymer composition are then rotationally molded to form a second (inner) layer on the inner surface of the first layer. In another embodiment, the first layer (which provides the outer wall of the containment vessel) is made using particles of a non-crosslinkable thermoplastic polymer composition, while the second layer (which provides the inner wall of the containment vessel) is prepared using a crosslinkable thermoplastic polymer composition that is converted to a thermoset polymer.

[0062] Once the containment container is formed, it can be combined with one or more additional components to obtain the container of the present invention. For example, the containment containers described herein can be fitted with a vent mechanism, a fill port, a dispensing tap, a protective cage, and / or a pallet. The assembled container can then be charged with a liquid composition, such as a liquid composition containing at least one compound that is at least one of flammable, combustible, explosive, or susceptible to exothermic decomposition, to obtain a packaged composition according to the present invention. The packaged composition can be stored and / or transported prior to use of the contents of the packaged composition, in which case at least a portion of the composition is withdrawn from the containment container (e.g., by means of a dispensing tap or dip tube) and then used for its intended purpose. For example, a composition containing an organic peroxide can be withdrawn and used to initiate polymerization or other chemical reactions requiring the organic peroxide.

[0063] Various non-limiting aspects of the present invention can be summarized as follows:

[0064] [Aspect 1] A container useful for storing and transporting a liquid composition (e.g., a liquid composition containing at least one compound that is at least one of flammable, combustible, explosive, or exothermically decomposable), the container comprising a containment vessel equipped with a vent mechanism and comprising a thermosetting polymer.

[0065] [Aspect 2] 10. The container of claim 1, wherein the thermoset polymer comprises at least one crosslinked thermoplastic polymer.

[0066] [Aspect 3] 2. The container of claim 1, wherein the thermosetting polymer comprises at least one crosslinked polyethylene.

[0067] [Aspect 4] 2. The container of claim 1, wherein the thermoset polymer comprises at least one crosslinked polyethylene selected from the group consisting of crosslinked chlorinated polyethylene; crosslinked low-density polyethylene; crosslinked linear low-density polyethylene; crosslinked high-density polyethylene; copolymers of ethylene and one or more comonomers selected from the group consisting of octene, heptene, hexene, pentene, butene, propene, and combinations thereof; and blends thereof.

[0068] [Aspect 5] Aspect 5. The container of any one of aspects 1-4, wherein the thermosetting polymer has a level of crosslinking effective to render the thermosetting polymer melt-resistant, and wherein the container is capable of withstanding a flame environment without failure or leakage for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, or 30 minutes when tested in accordance with Test Procedure Class Number 6020, Large Scale Testing for Fire Performance of Intermediate Bulk Containers (FM Approvals LLC, September 2016).

[0069] [Aspect 6] A container according to any one of aspects 1 to 5, wherein the containment container has an internal volume of 250 liters to 1500 liters.

[0070] [Aspect 7] 7. The container of any one of aspects 1 to 6, wherein the containment container is sufficiently transparent to allow the liquid composition packaged within the containment container to be detected externally with the naked eye.

[0071] [Aspect 8] Aspect 8. The container of any one of aspects 1-7, wherein the container further comprises a protective cage that at least partially surrounds the containment container and is attached to or includes a pallet.

[0072] [Aspect 9] Aspect 9. The container of any one of aspects 1 to 8, wherein the containment container is self-supporting, collapsible, or collapsible when empty.

[0073] [Aspect 10] Aspect 10. The container of any one of aspects 1-9, wherein at least a portion of the vent mechanism is integral with the containment container.

[0074] [Aspect 11] 11. The vessel of any one of claims 1 to 10, wherein the vent mechanism comprises a device selected from the group consisting of a rupture disk, a pressure release valve, a pop-off cap, a rupture bolt, a spring-loaded clamp ring, a pressure release portion comprising a thermoplastic polymer that melts when heated, and a pressure release portion in a wall of the containment vessel that is sufficiently thinner than the remainder of the wall of the containment vessel to controllably release pressure within the containment vessel when internal pressure is applied to the containment vessel before the containment vessel reaches its burst pressure.

[0075] [Aspect 12] 12. The container of any one of the preceding aspects, wherein the containment container further comprises one or more additives selected from the group including fillers, flame retardants, fire retardants, antioxidants, light stabilizers, internal and external mold release agents, and combinations thereof.

[0076] [Aspect 13] Aspect 13. The container of any one of aspects 1 to 12, wherein the containment container has a wall consisting of a single layer comprising the thermosetting polymer.

[0077] [Aspect 14] 13. The container of any one of embodiments 1 to 12, wherein the containment container has a wall comprising a plurality of layers with at least one layer comprising the thermosetting polymer.

[0078] [Aspect 15] 15. The container of any one of Aspects 1-12 or 14, wherein the containment container has a wall comprising a first layer containing a first thermosetting polymer and a second layer containing a second thermosetting polymer, wherein the first thermosetting polymer and the second thermosetting polymer are different from each other.

[0079] [Aspect 16] 16. The container of any one of aspects 1-15, wherein the thermosetting polymer exhibits at least 60% weight retention as measured by ASTM D-1998-06(2006).

[0080] [Aspect 17] 17. The container of any one of aspects 1 to 16, wherein the containment container has a wall with an average thickness of 0.5 mm to 125 mm.

[0081] [Aspect 18] Aspect 18. The container of any one of aspects 1-17, wherein the container further comprises at least one of a fill spout or a dispensing tap.

[0082] [Aspect 19] 19. The container of any one of aspects 1 to 18, wherein the thermosetting polymer is non-flammable.

[0083] [Aspect 20] A packaged composition comprising the container of any one of aspects 1 to 19 and a liquid composition packaged within the container.

[0084] [Aspect 21] 21. The packaged composition of embodiment 20, wherein the liquid composition contains at least one compound that is at least one of flammable, combustible, explosive, or exothermically decomposable.

[0085] [Aspect 22] 22. The packaged composition of embodiment 21, wherein the at least one compound comprises at least one organic peroxide.

[0086] [Aspect 23] 23. The packaged composition of claim 22, wherein the at least one organic peroxide is present in the composition in neat form, in solution in combination with one or more solvents, or in the form of an aqueous emulsion.

[0087] [Aspect 24] 1. A packaged composition comprising: a container and a liquid composition; and at least one compound packaged within the container, the compound being at least one of flammable, combustible, explosive, or exothermically decomposable; the container comprising a containment vessel for the composition, the containment vessel having an internal volume of 1000 liters or 1250 liters, the containment vessel having a vent mechanism and at least one of a fill port or a dispensing tap, and having a wall containing at least one crosslinked polyethylene having a crosslinking level effective to impart melt resistance to the at least one crosslinked polyethylene, whereby the container is capable of withstanding a flame environment for 20 minutes without failure or leakage when tested in accordance with Test Procedure Class Number 6020, Large Scale Testing for Fire Performance of Intermediate Bulk Containers (FM Approvals LLC, September 2016).

[0088] [Aspect 25] A method of making the container of any one of aspects 1-19, comprising forming the containment container by rotational molding, blow molding, or three-dimensional printing.

[0089] [Aspect 26] 26. The method of claim 25, further comprising molding a thermoplastic polymer into a precursor structure for the containment vessel, and then crosslinking the thermoplastic polymer of the precursor structure to convert the thermoplastic polymer into the thermoset polymer, thereby obtaining the containment vessel.

[0090] [Aspect 27] 27. The method of claim 26, wherein crosslinking of the thermoplastic polymer is achieved by a method selected from the group consisting of reacting the thermoplastic polymer with one or more free radical polymerization initiators (e.g., organic peroxides), optionally together with one or more crosslinking coagents; moisture-curing the thermoplastic polymer, wherein the thermoplastic polymer comprises silane groups; and radiation-curing, wherein the thermoplastic polymer is exposed to radiation.

[0091] [Aspect 28] A method of packaging a liquid composition, the method comprising introducing the liquid composition into a container according to any one of aspects 1 to 19.

[0092] While embodiments have been described herein in a manner that enables a clear and concise specification to be written, it is contemplated and will be recognized that the embodiments may be variously combined or separated without departing from the invention. For example, it will be recognized that all preferred embodiments described herein can be applied to all aspects of the invention described herein.

[0093] In some embodiments, the invention described herein may be considered to exclude various components or process steps that do not materially affect the basic and novel characteristics of the container, the method for making the container, and the compositions packaged using the container. Furthermore, in some embodiments, the invention may be construed to exclude various components and process steps not specified herein.

[0094] Although the invention is illustrated and described herein with reference to specific embodiments, it is not intended that the invention be limited to the details set forth below. Rather, various modifications may be made in detail within the scope and range of equivalents of the claims without departing from the invention.

[0095] Experimental equipment and procedures used in the examples The Alpha Technologies RPA® 2000E (which is a type of moving die rheometer, also known as "MDR" or "RPA") was used to study the crosslinking performance of peroxide formulations in rotomolding grades of HDPE resin. The RPA provided measurements of the final cure state MH (dN·m) and tc90 (min), which is the time required to reach 90% crosslinking. For these studies, the RPA was set at a strain of 1 degree arc and an oscillation frequency of 100 cpm (cycles per minute). The crosslinking temperature was set at 190°C for both the upper and lower die platens.

[0096] Abbreviations used in the examples MH = Maximum torque (unit: dN·m): related to the cross-link. ML = minimum torque (unit: dN·m) (Note: In the examples, the ML value was always zero and is therefore not shown in the data tables to save space). MH-ML = relative cross-linking degree (unit: dN·m). ts0.4 = scorch time (unit: minutes): The time it takes for the torque to increase by 0.4 dN m, starting from the minimum torque ML. This is defined as the time it takes for the crosslinking to start. It indicates the time it takes to reach 4% crosslinking, at which point the MH value is approximately 9-10 dN m. ts1 = scorch time (in minutes): the time it takes for the torque to increase by 1 dN m, starting from the minimum torque ML. Another scorch time delay measurement at about 10% crosslinking, at which point the MH value is about 9-10 dN m. tc90 = time to 90% of final hardening (unit: minutes). phr = parts by weight of ingredient per 100 parts by weight of resin (i.e., HDPE or polyethylene). Luperox® 101 = 2,5-dimethyl-2,5-di(t-butylperoxy)hexane HDPE = High Density Polyethylene CPE = Chlorinated Polyethylene [Example]

[0097] Example 1 U.S. Patent Application Publication No. 2008 / 0161526A1 (published July 3, 2008, entitled "Crosslinked Polyethylene Resin for Large Part Blow Molding," by Guenther et al.) teaches a large-scale blow molding method for polyethylene containers, drums, and IBCs (Industrial Bulk Containers) in paragraph

[0012] . Guenther states that these articles are crosslinked (peroxide-based) polyethylene. However, as shown in the examples below, the polyethylene obtained by Guenther is a thermoplastic plastic, not a thermoset. Guenther states that a maximum of 150 ppm of peroxide is used, and that too much peroxide results in an undesirable product (paragraph

[0019] ). Specifically, Guenther uses Luperox® 101 in Table 3 at levels ranging from 20 ppm to a maximum of only 150 ppm (paragraph

[0016] ).

[0098] In Example 1 herein, it is shown that when 150 ppm is used to crosslink HDPE at a cure temperature of 190°C according to the teachings of Guenther, the peroxide concentration is too low to result in a crosslinked HDPE polymer that is thermosetting, but rather thermoplastic.

[0099] The significance of the data presented in Table 1 below is that although Guenther claims to have produced a "crosslinked" polyethylene, Guenther's blow molding process requires a thermoplastic HDPE polymer, and the final polyethylene must closely resemble the virgin HDPE polymer in performance before it is reacted with peroxide. The RPA rheometer data for the inventive examples clearly show that after reaction with 150 ppm Luperox® 101, the resulting polyethylene behaves the same as virgin (non-peroxide) HDPE and exhibits identical rheology. Therefore, Guenther's "crosslinked" polyethylene would not have sufficient melt resistance to be useful for making containment containers (molded intermediate product containers having a capacity of 1000 liters or 1250 liters can withstand 20 minutes in a flame environment without failure or leakage when tested in accordance with Test Procedure Class Number 6020, Large Scale Testing for Fire Performance of Intermediate Bulk Containers (FM Approvals LLC, September 2016)).

[0100] The maximum MH torque (unit: dNm) is 0 dN m after modification with 150 ppm of Luperox® 101. HDPE without peroxide also showed a maximum MH torque of 0 dN m.

[0101] In comparison, HDPE crosslinked with 0.5 phr (5000 ppm) of Luperox® 101 exhibited a maximum MH torque and relative MH-ML (relative crosslinking degree) of 3.70 dN m (the minimum torque achieved was 0 dN m). As can be seen in Table 1, increasing the amount of Luperox® 101 used resulted in a higher relative crosslinking degree (MH-ML).

[0102] In summary, after reacting HDPE with 150 ppm of Luperox® 101 according to the procedure described by Guenther, the final HDPE polymer was essentially the same as the original HDPE (without the peroxide); therefore, the polyethylene used by Guenther to blow mold his IBC containers was thermoplastic and not truly crosslinked (thermoset). See Table 1 below and the rheographs shown in Figures 1 and 2. Therefore, containment containers made from such polyethylene would melt and would not survive in a flame environment.

[0103] [Table 1]

[0104] Example 2 In this example, HDPE and blends of HDPE and CPE (36% chlorine content) were cured. The peroxide formulation used, "Curing Agent E-2," is shown in Table 2. The curing agent level was varied from 1.0 phr to 1.5 phr. The relative amount of crosslinking was determined from the MH-ML values (units: dN·m) measured using an RPA rheometer at 190°C for 8 minutes, using a 1-degree arc strain and a frequency of 100 cpm (cycles per minute).

[0105] [Table 2]

[0106] [Table 3]

[0107] This example demonstrates that blends of HDPE and CPE can be crosslinked for rotomolding applications to make containment containers for IBCs. Based on the measured MH-ML values (units: dN m = deciNewton meters), higher concentrations of curing agent E-2 result in higher crosslinking degrees. For the production of containment containers for IBCs by rotomolding operations, a minimum relative crosslinking degree of 7 dN m is desirable, which was achieved using 1.0 phr of the curing agent composition in Table 2. To obtain a thermosetting polymer useful for making containment containers for IBCs according to the present invention, it is preferred to use at least 1.25 phr of "Curing Agent E-2," with 1.5 phr being more preferred.

[0108] Example 3 In this Example 3, the flammability of HDPE, cross-linked HDPE, CPE, and cross-linked CPE was investigated. No flame retardant chemicals, antioxidants, or fillers were added to the polymers. In this example, the original polymers were tested alone to investigate the effect of cross-linking on the polymer's ability to withstand a fire.

[0109] The original HDPE and CPE polymers were in the form of fine powders. Test bars measuring 5 inches long, 0.5 inches wide, and 1 / 8 inch thick were molded from each powder. The HDPE powder used had a density of 0.94-0.97 g / cm. 3 The powdered CPE polymer was said to have a chlorine content of 36%.

[0110] A molding temperature of 185°C was used to prepare HDPE (non-crosslinked high density polyethylene) and XL-HDPE (crosslinked HDPE) test bars. A molding temperature of 195°C was used to prepare CPE (non-crosslinked chlorinated polyethylene) and XL-CPE (crosslinked chlorinated polyethylene) test bars. In each case, a Carver press was used to mold the HDPE, crosslinked HDPE, CPE, and crosslinked CPE test bars, and the molding operation was carried out at 15,000 psi for 20 minutes. Five test bars were prepared.

[0111] When making crosslinked HDPE and CPE bars, a 4 phr amount (parts of peroxide formulation per 100 parts of polymer resin) was carefully added to the polymer powder prior to using the molding procedure described above. This was done using a small bullet high-speed blender and mixed for several minutes to homogenously blend the molten peroxide formulation with the powdered HDPE and CPE. The peroxide formulation used was "Curing Agent E-3," the composition of which is shown in Table 4. This peroxide composition is partially liquid at room temperature, so it was placed in a container and placed in a hot air oven set at 60°C for about an hour to fully melt it before adding it to the powdered polymer.

[0112] [Table 4]

[0113] [Table 5]

[0114] Sample bars using the polymer powder formulations in Table 5 were molded using a carver press using the conditions described earlier in this example. These bars were used in the gas flame combustion test described herein. The polymer test bars (A-D) were clamped in a vertical position, and the bottom of the bar was engulfed / exposed to a gas flame; once the bar began to ignite, the gas flame was removed, observed, and recorded.

[0115] [Table 6]

[0116] This example demonstrates the importance of using crosslinked polymers and how such crosslinked polymers can behave in a fire environment. None of these polymers contain any additional fire retardant components. When designing polymer formulations for molding or manufacturing IBC containers, it is preferred / desired to use a fire retardant additive, which, when added to the CPE, will crosslink it to form an XL-CPE that contains the fire retardant.

[0117] The purpose of this example is to demonstrate the value of organic peroxide formulations in crosslinking selected polymers to provide an additional layer of protection in a fire environment. The polymers used in this example did not contain any fire retardants. As seen in Table 6, "Sample Bar Gas Flame Test Results," XL-CPE (crosslinked CPE) with no added fire retardants self-extinguished in only 3 seconds, compared to 33 seconds for the uncrosslinked CPE with no added fire retardants.

Claims

1. A container useful for storing and transporting a liquid composition, said container comprising a containment vessel equipped with a vent mechanism and containing a thermosetting polymer; the thermosetting polymer comprises crosslinked chlorinated polyethylene; The container has a torque value of at least 7 dN·m when measured in accordance with ASTM D-5289-95 using a moving die rheometer under test conditions of 190° C., 100 cpm, and 1 degree arc.

2. 10. The container of claim 1, wherein the thermosetting polymer comprises at least one crosslinked thermoplastic polymer.

3. 10. The container of claim 1, wherein the thermosetting polymer comprises at least one cross-linked polyethylene.

4. 4. The container of claim 1, wherein the containment vessel has an internal volume of between 250 liters and 1500 liters.

5. 5. The container of claim 1, wherein the containment vessel is transparent, allowing the liquid composition packaged inside the containment vessel to be detected from the outside with the naked eye.

6. 6. The container of any one of claims 1 to 5, wherein the container further comprises a protective cage at least partially surrounding the containment vessel and attached to or including a pallet.

7. A container according to any preceding claim, wherein the containment vessel is self-supporting or collapsible when empty.

8. The container of any one of claims 1 to 7, wherein at least a portion of the vent mechanism is integral with the containment vessel.

9. 9. The container of any one of claims 1 to 8, wherein the vent mechanism comprises a device selected from the group consisting of a rupture disk, a pressure release valve, a pop-off cap, a rupture bolt, a spring-loaded clamp ring, a pressure release portion containing a thermoplastic polymer that melts when heat is applied, and a pressure release portion in a wall of the containment vessel that is sufficiently thinner than the remainder of the wall of the containment vessel to controllably release pressure within the containment vessel when internal pressure is applied to the containment vessel before the burst pressure of the containment vessel is reached.

10. 10. The container of any one of claims 1 to 9, wherein the containment vessel further comprises one or more additives selected from the group consisting of fillers, flame retardants, fire retardants, antioxidants, light stabilizers, internal and external mold release agents, and combinations thereof.

11. 11. The container of any one of claims 1 to 10, wherein the containment vessel has a wall consisting of a single layer comprising the thermosetting polymer.

12. 11. The container of any one of claims 1 to 10, wherein the containment vessel has a wall comprising multiple layers with at least one layer comprising the thermosetting polymer.

13. 13. The container of any one of claims 1 to 10 or 12, wherein the containment vessel has a wall comprising a first layer containing a first thermosetting polymer and a second layer containing a second thermosetting polymer, the first thermosetting polymer and the second thermosetting polymer being different from each other.

14. 14. The container of any one of claims 1 to 13, wherein the thermosetting polymer exhibits at least 60% weight retention as measured by ASTM D-1998-06(2006).

15. 15. A container according to any preceding claim, wherein the containment vessel has walls with a thickness of between 0.5mm and 125mm.

16. The container of any one of claims 1 to 15, wherein the container further comprises at least one of a fill port or a dispensing tap.

17. 17. The container according to any one of claims 1 to 16, wherein the thermosetting polymer is non-flammable and will not ignite when exposed to an open flame.

18. A packaged composition comprising a container according to any one of claims 1 to 17 and a liquid composition packaged within said container.

19. 20. The packaged composition of claim 18, wherein the liquid composition contains at least one compound that is at least one of flammable, combustible, explosive, or exothermically decomposable.

20. 20. The packaged composition of claim 19, wherein the at least one compound comprises at least one organic peroxide.

21. 21. The packaged composition of claim 20, wherein the at least one organic peroxide is present in the packaged liquid composition in undiluted form, in the form of a solution in combination with one or more solvents, or in the form of an aqueous emulsion.

22. A method of making a container according to any one of claims 1 to 17, comprising forming the containment vessel by rotational moulding, blow moulding or three-dimensional printing.

23. 23. The method of claim 22, further comprising molding a thermoplastic polymer into a precursor structure for the containment vessel, and thereafter crosslinking the thermoplastic polymer of the precursor structure to convert the thermoplastic polymer to the thermoset polymer, thereby obtaining the containment vessel.

24. 24. The method of claim 23, wherein crosslinking of the thermoplastic polymer is achieved by a method selected from the group consisting of reacting the thermoplastic polymer with one or more free radical polymerization initiators, optionally together with one or more crosslinking coagents; moisture curing the thermoplastic polymer, wherein the thermoplastic polymer includes silane groups; and radiation curing, wherein the thermoplastic polymer is exposed to radiation.

25. A method of packaging a liquid composition, the method comprising the step of introducing the packaged liquid composition into a container according to any one of claims 1 to 17.

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