Corrosion protection packaging material

Abstract

The invention provides a corrosion protection packaging material designed for surface application. The packaging material is characterized by a flat strip-like structure having both an inner surface and an outer surface. The present invention relates to a composite material comprising two distinct layers: a first layer made of homopolymerized PIB having a specific molecular density, suitable for adhesion properties, forming the inner surface, and a second layer made of homopolymerized PIB having a specific molecular density, forming the outer surface. And a second layer consisting of a homopolymerized PIB or elastomeric polymer having different molecular densities, suitable for mechanical elasticity, creating the outer surface. The two layers are adhered to each other along a compatibility plane.

Description

Technical Field

[0001] The present invention relates to a corrosion protection packaging material for application to the surface of a structural element, such as a pipe or a roofing sheet. Background Art

[0002] In the following, the words "tape" and "strip" are used interchangeably to refer to a long, relatively narrow, flexible strip of material used for mechanical corrosion protection of the surface of a structural element.

[0003] Any structural element exposed to corrosive elements will require the application of a corrosion resistant coating to protect the structure and increase the functional life of the structural element.

[0004] There are many methods for coating the surface of a structural element with a corrosion resistant material. One common method, particularly when coating underground pipelines used, for example, to transport water, sewage, oil, gas and petrochemical fluids, is to wrap a tape or strip of corrosion resistant material around the pipeline section.

[0005] Typical wrapping methods for applying a corrosion-resistant layer to a pipe section involve a complex, expensive, multi-step process that includes some or all of the following steps: 1. preheating the pipe section; 2. sandblasting the outer surface of the pipe section to the required standard; 3. surface grinding the outer surface; 4. selecting a surface profile; 5. inspecting the outer surface; 6. testing for surface residues, i.e., chloride salts; 7. applying a first primer (anti-corrosion paint or wet-applied anti-corrosion material) to the outer surface; 8. wrapping tape around the pipe section to provide a corrosion-resistant bonding layer; 9. applying a mechanically resistant overwrap of PVC, PP, HDPE, etc. to the bonding layer to provide a mechanical layer; and 10. inspecting the pipe section's coating for discontinuities using a conductivity test.

[0006] Clearly, the pipe sections require extensive pre-coating preparation to ensure that the exterior surface is clean and free of any film or scale, and has the required surface profile (of SA 2,5-3) to ensure the primer adheres to the exterior surface.

[0007] The bonding layer is typically an adhesive comprising a mixture of butyl and bitumen, the mix ratio of which varies depending on the manufacturer and function, but the goal is to achieve a high level of adhesion. The problem with this adhesive blend is that it loses flexibility over time and becomes brittle.

[0008] The adhesive layer plays a key role in attaching the outer protective layer to the pipe. To ensure that the adhesive layer is sufficiently sticky, it is preferably a homopolymer. This requirement eliminates the cost-saving opportunity of using copolymer PIB, which is less sticky and more susceptible to corrosion.

[0009] PIB is a general term used to describe not only isobutylene homopolymers (isobutylene being the only constituent monomer) but also copolymers or terpolymers composed of isobutylene and other monomers.

[0010] Co-PIBs (Co-PIBs) are produced by copolymerizing isobutylene with other monomers to produce polymers with a combination of properties derived from the different monomers. Co-PIBs offer versatility and customization options for a variety of industrial and commercial applications.

[0011] An example of a Co-PIB copolymer is isobutylene isoprene rubber (IIR), a PIB-based rubber with repeating units of both isobutylene and isoprene. It is known for its excellent air-impermeability and is commonly used in the production of tire inner tubes, O-rings, and other products requiring high gas barrier properties.

[0012] Homopolymeric PIB (Ho-PIB) is made solely from isobutylene monomer, resulting in a highly uniform and consistent polymer structure. It is frequently used in applications requiring reliable and consistent properties, such as in the adhesives industry.

[0013] PIB can be further divided into three categories based on molecular weight, regardless of whether they are Ho-PIB or Co-PIB, which are: (1) low molecular weight PIB (LMW PIB) has a relatively low molecular weight, ranging from 500 to 10,000 g / mol, which means that it consists of fewer repeating units in its polymer chain, is typically a low viscosity liquid at room temperature, and is commonly used as a lubricant, as an additive in motor oil, and in the production of certain sealants and adhesives; (2) medium molecular weight PIB (MMW PIB) has a medium molecular weight, ranging from 10,000 to 100,000 g / mol, between low molecular weight PIB and high molecular weight PIB, and is used in applications where a balance between viscosity and tack is required, such as adhesive manufacturing; and (3) high molecular weight PIB (HMW PIB) has a high molecular weight, ranging from above 100,000 g / mol, which means that it has a long polymer chain containing many repeating units, is typically a high viscosity liquid or solid at room temperature, and is a grade that generally provides mechanical strength, impact resistance, chemical resistance, and rubbery properties.

[0014] As is evident from the above discussion, the typical packaging approach is a multi-step process employing a three-layer coating process that increases complexity and cost.

[0015] Therefore, it would be advantageous to envision a single packaged product that has both adhesive molecular attachment properties on one surface and an outer surface that is resistant to mechanical stress. This necessity typically requires adhering two layers of different chemical compositions together. Adhering two such layers together creates a potentially expensive solution that will have an interface that compromises the integrity of the resulting product.

[0016] The present invention at least partially solves this problem. Summary of the Invention

[0017] Hereinafter, "homopolymeric PIB" refers to a polymer made solely from the monomer isobutylene (also known as isobutylene), and includes mixtures of homopolymeric PIB with various additives or other materials to achieve specific performance characteristics or properties.

[0018] When used to describe the second layer, "mechanically resistant" means that the layer and the materials it contains are relatively resistant to at least fatigue, stress, heat, oxidation, and impact when compared to the first layer.

[0019] In the context of the first layer, the term "adhesive" means that the layer, together with its constituent materials, exhibits a relatively high level of adhesion, tack or cohesion compared to the second layer. The material is capable of forming a molecular level bond with metallic, polymer-based and cementitious substrates.

[0020] The present invention provides a corrosion protection packaging material for application to a surface, comprising at least homopolymeric PIB, having an elongated planar strip having an inwardly facing surface and an outwardly facing surface, and comprising at least:

[0021] a first layer comprising a first material of homopolymeric PIB of a first molecular density, adapted to have adhesive properties, and providing said inwardly facing surface; and

[0022] a second layer comprising at least a second material comprising homo-PIB of a second molecular density or an elastomeric polymer, adapted to have mechanically resistant properties, and providing said outwardly facing surface; and

[0023] The first layer and the second layer are bonded along a compatibility plane.

[0024] The elastomeric polymer may include natural rubber or any one or more of the following synthetic polymers: isobutylene isoprene rubber (IIR), ethylene propylene diene monomer (EPDM), ethylene propylene diene monomer (EPR), ethylene octene (EO), ethylbenzene (EB), and styrene ethylene butadiene styrene (SEBS).

[0025] The first molecular density of the first material of the homopolymer PIB can be in the range of 25-65 g / cm 3 within the range.

[0026] The first material of the homopolymer PIB may be a MMW PIB.

[0027] Preferably, the first material of the homopolymeric PIB may be a blend of constituent polymers in order to obtain an average molecular weight between 40,000 g / mol and 85,000 g / mol.

[0028] The ratio of the constituent polymers in the blend may depend at least on the temperature of the environment in which the packaging material is to be used.

[0029] Preferably, the average molecular weight of each constituent polymer in the blend is 1,500; 2,400; 20,000; 36,000; 56,000; or 75,000.

[0030] The thickness of the first layer may be between 200 μm and 3000 μm.

[0031] Preferably, the thickness of the first layer is between 500 μm and 900 μm.

[0032] The first material of homopolymeric PIB may include any one or more of the following additives (added to the first material to form the mixture): antioxidants, colorants, and extenders (fillers).

[0033] The extenders may be glass beads, preferably hollow glass beads, having a diameter equal to the desired thickness of the first layer.

[0034] The second molecular density of the second material of the homopolymer PIB can be in the range of 120-180 g / cm 3 within the range.

[0035] The second material of homopolymeric PIB may be HMW PIB.

[0036] Preferably, the second material of the homopolymeric PIB may be a blend of polymers to achieve an average molecular weight between 200,000 g / mol and 4,000,000 g / mol.

[0037] The ratio of the constituent polymers in the blend may depend at least on environmental parameters (in the environment in which the packaging material is to be used), such as exposure to oxidation and temperature, and functional parameters, such as impact properties.

[0038] Preferably, the average molecular weight of each constituent polymer in the blend is 750,000; 2,500,000 or 4,100,000.

[0039] The thickness of the second layer may be between 500 μm and 5000 μm.

[0040] Preferably, the thickness of the second layer is between 800 μm and 1000 μm.

[0041] The second material of the homopolymeric PIB may include one or more of the following additives (added to the second material to form the mixture): antioxidants, colorants, processing aids, and extenders (fillers).

[0042] The extenders may be glass beads, preferably hollow glass beads, having a diameter equal to the desired thickness of the second layer.

[0043] The width of the elongate planar strip of packaging material may be in the range 50 mm to 400 mm.

[0044] Structural elements can be pipe sections, roof panels, etc.

[0045] By applying a liquefied first material, which provides the homopolymeric material of the first layer, to the second layer, the first and second layers may be bonded along a line of compatibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Embodiments of the present invention will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0047] Figure 1 An isometric illustration of a cross section of a corrosion-resistant packaging material according to the present invention;

[0048] Figure 2 Isometric illustration Figure 1 a cross-section in which the first layer of packaging material is partially pulled away from the second layer of packaging material; and

[0049] Figure 3 is a cross-sectional view of a pipe where packaging material is applied. DETAILED DESCRIPTION

[0050] In the context of PIB materials, the terms "mixture" or "blend" are used interchangeably to refer to a mixture of a constituent PIB polymer of known average molecular weight combined with various additives or other materials to achieve specific performance characteristics or properties. These additives are blended with the PIB polymer to modify its behavior, enhance its functionality, or adapt it for various applications. The resulting composite can possess a range of properties tailored to meet the requirements of a specific industry or use case. Some common additives and materials that can be combined with PIB to produce composites include (1) fillers (such as carbon black, silica, or clay) added to improve the mechanical strength, wear resistance, and dimensional stability of the composite; (2) plasticizers added to enhance the flexibility and flow characteristics of the composite, making it more suitable for specific applications (such as sealants or adhesives); (3) antioxidants added to prevent oxidation of the PIB, which can degrade its performance over time; (4) vulcanizing agents, which in the case of PIB-based rubber composites such as isobutylene isoprene rubber (IIR), are used to crosslink the polymer chains and improve the strength and elasticity of the material; (5) processing aids added to aid in the manufacture and processing of PIB composites, improving their workability and ease of application; (6) colorants or dyes added to provide the composite with a specific color or appearance (which can be used for identification or aesthetic purposes); and (7) stabilizers, which are used to protect the composite from degradation caused by heat, UV radiation, or other environmental factors.

[0051] refer to Figure 1 and Figure 2 According to the present invention, a corrosion protection packaging material 10 is provided.

[0052] exist Figure 3 In, for example, a wrapping material is applied to a steel pipe 12. The pipe has an exterior surface 14 that requires corrosion protection.

[0053] The corrosion-resistant packaging material 10 comprises an elongated planar strip 16 of indefinite length, preferably provided in rolls or sections to be untied before use, and having a width (denoted as W) between 50 mm and 400 mm depending on the application.

[0054] The strip has a first layer 18 having a thickness (denoted as "t") between 800 μm and 3000 μm and a second layer 20 having a thickness (denoted as "T") between 800 μm and 5000 μm, which are adhered together along their respective inner surfaces (denoted as 22.1 and 22.2 respectively) by a co-extrusion manufacturing method.

[0055] The benefit of having the two layers be identical in monomer and made of PIB is that the layers bond together almost seamlessly without the need for additive adhesives. However, for descriptive purposes and when defining the two layers, a compatibility line or plane 24 is designated between the two layers.

[0056] The first and second layers present exposed surfaces, substrate adhesion (or inwardly facing) surface 26 and outwardly facing surface 28, respectively.

[0057] In use, the packaging material 10 is adhered to a substrate, in this example the pipe 12, by applying the substrate adhesion surface 26 to the outer surface 14 of the pipe.

[0058] In this example, both first layer 18 and second layer 20 are a single, homogeneous unit made of PIB. PIB possesses all the necessary properties for this type of packaging material. It is tacky, chemically and UV-resistant, and elastic (returning to its original dimensions after deformation), while also providing good mechanical and impact resistance and hoop strength. Furthermore, PIB never becomes brittle or dry and is always able to flow.

[0059] The first layer comprises a first PIB material comprising PIB having an average molecular weight (MMW) in the range of 40,000-85,000 g / mol. Within this range, the PIB has tack that provides exceptionally good adhesion to all substrates, including metals, polymers, cementitious materials, and glass, as well as other materials with low micron surface roughness.

[0060] To achieve a specific average molecular weight for the first PIB material, the choice will depend on the ambient temperature in which the packaging material will be used. This includes blending PIB polymers of known composition with various average molecular weights, selected from polymers having average molecular weights of 1,500; 2,400; 20,000; 36,000; 56,000; or 75,000.

[0061] The second layer includes a second PIB material comprising PIB having an average molecular weight (HMW) in the range of 200,000-4,000,000 g / mol. Within this range, the higher molecular weight imparts mechanical properties of improved crush resistance, high impact resistance, scratch resistance, and abrasion resistance to the material, UV resistance, and gas barrier properties, while still having high elasticity, hoop strength, and flexibility.

[0062] To achieve a specific average molecular weight for this second PIB material, the selection process also considers various factors beyond simply the ambient temperature of the packaging material's environment. These additional factors include considerations for oxidation and shock exposure, which influence the material's molecular weight selection. This involves blending PIB polymers of known composition with various average molecular weights, selected from polymers with average molecular weights of 750,000, 2,500,000, or 4,100,000.

[0063] The corrosion protection packaging material 10 can be manufactured using one of three different manufacturing techniques: single extrusion, coextrusion, and roll-flat sheeting.

[0064] Single-shot extrusion is a manufacturing method used to produce flat profiles with a consistent cross-sectional shape. The process involves introducing a raw material (typically a thermoplastic or rubber) into a heated barrel. The material is then melted within the barrel and pushed through a die, which imparts the desired shape. The result is a continuous, uniform profile characterized by a consistent material composition throughout.

[0065] Coextrusion represents a variation of the extrusion process in which two or more materials are extruded simultaneously to form a single product with multiple layers. In this method, each material is fed independently into its own dedicated extruder. The molten materials are then mixed in a dedicated die to create the multilayer structure. Coextrusion is often used to enhance specific product attributes, including adding protective layers to improve durability or blending various colors or materials to meet aesthetic or functional requirements.

[0066] In cases where coextrusion involves the use of polymers of different molecular weights but the same type, two or more extruders participate in the process. Each extruder contains the same polymer, albeit with different molecular weights. These materials are mixed with additives to impart properties such as coloration, uniform color distribution, adhesion, and mechanical properties. These different materials are then brought together in a die or dedicated manifold and then coextruded into a single product. This method uses polymers of different molecular weights but the same type, making it possible to exploit the unique properties associated with different molecular weight polymers within a single product.

[0067] Generally, polymers with higher molecular weights tend to contribute to properties such as strength and rigidity, while lower molecular weight polymers offer advantages such as flexibility and impact resistance. The combination of materials with different molecular weights enables the design of products with a broad spectrum of physical and mechanical properties, making this approach highly versatile and suitable for a variety of applications.

[0068] The method offers excellent control over the properties of the final product, thereby enhancing its performance, durability and functionality.

[0069] Roll sheeting is a manufacturing process used to create thin, flat sheets from a variety of materials. In this process, the material is typically fed through a series of rollers, which gradually reduce its thickness while producing a flat, uniform sheet. Roll sheeting has utility in a wide range of industries, where the material is typically pre-melted in an extruder and then fed to rollers to achieve the desired dimensions.

[0070] Polymers of the same type but with different molecular weights are then brought together in a die or specialized manifold and extruded into a single product.

[0071] Polymers with higher molecular weights generally contribute to properties such as strength and stiffness, impact capability, etc., while lower molecular weight polymers provide benefits such as flexibility and adhesion to various substrates.

[0072] As outlined in this invention, combining various constituent polymers with different molecular weights in each layer, and subsequently combining the two layers with different molecular weights, enables the creation of a wide variety of customized products. These products are tailored to exhibit varying physical and mechanical properties, specifically designed for specific applications. This innovation, therefore, introduces versatility to an industry previously limited by available products and application processes.

[0073] PIB is a preferred polymer for the present invention because it adheres strongly to a wide variety of substrates while maintaining fluidity without curing. However, within the scope of the present invention, it is foreseen that IIR or butyl rubber could be used as an alternative to PIB in the second layer. However, this substitution has disadvantages; although IIR is less expensive, it tends to deteriorate over time, compromising its technical performance.

Claims

1. A corrosion protection packaging material for application to a surface, comprising at least homopolymer PIB, having an elongated planar strip having an inward-facing surface and an outward-facing surface, and comprising at least a first layer and a second layer; the first layer comprising a first material of homopolymer PIB of a first molecular density, adapted to have adhesive properties, and providing the inward-facing surface; the second layer comprising a second material of at least homopolymer PIB of a second molecular density or an elastomeric polymer, adapted to have mechanical resistance properties, and providing the outward-facing surface; and wherein the first layer and the second layer are bonded along a compatibility plane.

2. The corrosion protection packaging material according to claim 1, wherein the elastomeric polymer comprises natural rubber or any one or more of the following synthetic polymers: isobutylene isoprene rubber (IIR), ethylene propylene diene monomer rubber (EPDM), ethylene propylene diene monomer rubber (EPR), ethylene octene (EO), ethylbenzene (EB) and styrene ethylene butadiene styrene (SEBS).

3. The corrosion protection packaging material according to claim 1 or 2, wherein the first molecular density of the first material of the homopolymeric PIB is in the range of 25-65 g / cm3.

4. The corrosion protection packaging material according to any one of claims 1 to 3, wherein the first material of homopolymeric PIB is a blend of polymers to achieve an average molecular weight between 40,000 g / mol and 85,000 g / mol.

5. The corrosion protection packaging material according to claim 4, wherein the average molecular weight of each component polymer in the blend is 1,500, 2,400, 20,000, 36,000, 56,000 or 75,000. 6 . The corrosion protection packaging material according to claim 1 , wherein the thickness of the first layer is between 200 and 3000 μm. The corrosion protection packaging material according to claim 6 , wherein the thickness of the first layer is 500 μm to 900 μm.

8. The corrosion protection packaging material according to any one of claims 1 to 7, wherein the first material of homopolymeric PIB comprises any one or more of the following additives: an antioxidant, a colorant, and an extender. 9 . The corrosion protection packaging material according to claim 8 , wherein the extender is glass beads or hollow glass beads having a diameter equal to the desired thickness of the first layer.

10. The corrosion protection packaging material according to any one of claims 1 to 9, wherein the second molecular density of the second material of the homopolymeric PIB is in the range of 120 to 180 g / cm3.

11. The corrosion protection packaging material according to any one of claims 1 to 10, wherein the second material of homopolymeric PIB is a blend of polymers to achieve an average molecular weight between 200,000 g / mol and 4,000,000 g / mol.

12. The corrosion protection packaging material according to any one of claims 1 to 11, wherein the average molecular weight of each constituent polymer in the blend is 750,000, 2,500,000 or 4,100,000.

13. The corrosion protection packaging material according to any one of claims 1 to 12, wherein the thickness of the second layer is in the range of 500 μm to 5000 μm. The corrosion protection packaging material according to claim 13 , wherein the second layer has a thickness of 800 μm to 1000 μm.

15. The corrosion protection packaging material according to any one of claims 1 to 14, wherein the second material of homopolymeric PIB comprises one or more of the following additives: antioxidants, colorants, processing aids, and extenders. 16 . The corrosion protection packaging material according to claim 15 , wherein the extender is glass beads or hollow glass beads having a diameter equal to the desired thickness of the second layer.

17. The corrosion protection packaging material according to any one of claims 1 to 16, wherein the width of the elongated planar strip of packaging material is in the range of 50 mm to 400 mm.

18. The corrosion protection packaging material according to any one of claims 1 to 17, wherein the structural element is a pipe section.

19. The corrosion protection packaging material according to any one of claims 1 to 18, wherein the first and second layers are bonded along a compatibility line by applying a liquefied first material providing the homopolymeric material of the first layer to the second layer.

Images