RU236759U1 - ANTI-CORROSION PACKAGING MATERIAL - Google Patents

Abstract

The utility model relates to an anticorrosive packaging material for large-sized metal products, comprising a first layer made of a polymer film and a second layer made of a fibrous material, connected to each other. The anticorrosive packaging material is a web of strips connected to each other along the longitudinal edges. The technical result provided by the utility model consists in the implementation of its purpose. 2 c.p. f-ly.

Description

Field of technology

The utility model relates to flexible packaging materials with anti-corrosion properties and is intended to protect metal products from atmospheric corrosion, including heavy and large ones, such as rolls and packs of flat rolled metal, bundles of pipes, rods, ingots, engineering products, metal structures and other metal products during loading and unloading operations, transportation and storage.

Prior art

Anti-corrosion tapes are known, intended for winding on metal products, mainly pipelines, having a base made of polymer film, a mastic sealing layer and an anti-adhesive layer (see, for example, patent RU 90527 U1, 10.01.2010, and GOST R 52602-2006. Anti-corrosion polymer-asmol tape "Liam". Technical conditions: national standard of the Russian Federation: date of introduction 2008.01.01/ Federal Agency for Technical Regulation and Metrology. - Official Publ. - Moscow: Standartinform, 2007. - 12 p.).

These anti-corrosion tapes are produced in widths from 100 mm to 500 mm, have adhesion to the protected product and to the polymer film base, ensuring tightness. The disadvantage of these tapes is the impossibility of quickly removing the mastic from the surface of the metal product.

The above disadvantage is eliminated in an anti-corrosion packaging material having one layer of polymer film and another layer of fibrous material (see, for example, patent RU 92663 U1, published 27.03.2010). The tape is wound on a metal product in a spiral, overlapping, so that the layer of fibrous material is adjacent to the metal product. Spiral winding is used mainly for long products and usually involves the use of automatic lines. In most cases under consideration, the packaging of metal products is carried out manually. Wrapping massive, large-sized products with relatively narrow tapes is problematic.

For such products, anti-corrosion packaging materials of a relatively large width are used. For example, paper according to GOST 16295-2018. Anti-corrosion paper. Technical conditions: Interstate standard: date of introduction 2019.04.01 / Federal Agency for Technical Regulation and Metrology. - Official ed. - Moscow: Standartinform, 2018. - 27 p. (hereinafter - GOST 16295-2018), has a width of 700 to 1280 mm. When water gets inside the package, the paper gets wet, loses its physical and mechanical properties and in this state can provoke metal corrosion.

The closest analogue of the utility model is the anti-corrosion packaging material disclosed in patent document RU 163798 U1, 10.08.2016, having a first layer made of polymer film and a second layer made of fibrous material connected to each other. This material has a maximum width of 1500 mm. When wrapping a metal product with this material, its edges are overlapped, the size of which is usually 100-150 mm, therefore, with a width of anti-corrosion packaging material of 1500 mm, the perimeter of the cross-section of the metal product should not exceed 1300 mm.

The specified width is not enough to wrap large products, so several strips of anti-corrosion packaging material are used for packaging. In this case, water can get into the package to the protected product through the edges of the strips of anti-corrosion packaging material, which are overlapped (through the second layer made of fibrous material). In addition, for anti-corrosion materials containing corrosion inhibitors embedded in the second layer, there is a possibility of volatile corrosion inhibitors escaping into the atmosphere. These factors lead to a decrease in the level of anti-corrosion protection of anti-corrosion materials.

Disclosure of the essence of the utility model

The objective of the utility model is to expand the range of anti-corrosion packaging materials and create an anti-corrosion packaging material for large-sized metal products that reliably protects metal products from corrosion.

The technical result provided by the utility model consists in the implementation of its purpose.

The specified technical result is achieved in that the anti-corrosion packaging material for large-sized metal products contains a first layer made of polymer film and a second layer made of fibrous material, connected to each other, wherein the anti-corrosion packaging material is a web of strips connected to each other along the longitudinal edges.

The anti-corrosion packaging material may additionally contain a reinforcing layer connected to the first layer on the side opposite to that from which the first layer is connected to the second layer.

The anti-corrosion packaging material may also contain an additional barrier layer that increases the tightness of the anti-corrosion packaging material, connected to the second layer on the side opposite to that from which the second layer is connected to the first layer.

Implementation of a utility model

For packaging a metal product, an anti-corrosion packaging material is used according to the utility model, comprising a first layer made of a polymer film and a second layer made of a fibrous material, connected to each other, wherein the anti-corrosion packaging material is a web of strips connected to each other along the longitudinal edges.

Packaging of a metal product using anti-corrosion packaging material according to the utility model is, in most cases, carried out manually, for example, as follows.

Anti-corrosion packaging material of the appropriate length and width is spread out on a specially designated horizontal area. The anti-corrosion packaging material is placed with the second layer facing up. The metal product is placed on the anti-corrosion packaging material. After that, the metal product is wrapped with the anti-corrosion packaging material. The edges of the anti-corrosion packaging material are overlapped along the length and width, fixed and/or sealed, for example, with adhesive tape. Thus, the second layer of fibrous material is adjacent to the metal product, the first layer of polymer film is located on the outside and is a barrier, since it prevents water from getting inside the package. There may be other options for packaging metal products.

The width of the web of anticorrosive packaging material required to wrap a metal product is defined as the sum of the perimeter of the cross-section of the metal product at its widest part and the value required to ensure the required value of the overlap of the edges of the anticorrosive packaging material. The length of the web of anticorrosive packaging material required to wrap a metal product is defined as the sum of the perimeter of the vertical section along the length of the metal product at its longest part and the value required to ensure the required value of the overlap of the edges of the anticorrosive packaging material. The width of the web of anticorrosive packaging material required to wrap metal products with voids is determined by the packaging scheme. For example, to wrap a pack of rectangular pipes, the width of the web of anticorrosive packaging material can be determined by the formula

B = 2(h + b + l), where

B - width of the anti-corrosion packaging material web, m;

h - height of a bundle of rectangular pipes, m;

b - width of a bundle of rectangular pipes, m;

l - the overlap size of the edges, m.

The width of the web of anti-corrosion packaging material for wrapping a roll of flat rolled metal is usually determined as

B = 2(R - r + c + l), where

R - outer radius of a roll of flat rolled metal, m;

r - radius of the hole in a roll of flat rolled metal, m;

c - width of flat rolled metal strip, m.

As a rule, the minimum width of anti-corrosion packaging material for wrapping large metal products is 1.8 m. For example, for packaging bundles of pipes or rods.

The most widespread application of anti-corrosion packaging material is for wrapping (packaging) rolls and packs of flat rolled metal products. In this case, anti-corrosion packaging material with a width of 2.0-4.5 m is usually used.

Anti-corrosion packaging material with a width of 4.0-5.0 m is used mainly for packaging metal structures, engineering products, etc.

The length of the anti-corrosion material for wrapping products is usually from 1.5 m to 20 m.

To create an anticorrosive packaging material in one sheet with a width from 1.8 m to 5.0 m, it is necessary to connect the edges of individual strips of anticorrosive packaging material together in the longitudinal direction. When connecting strips of anticorrosive packaging material, an anticorrosive packaging material made in the form of a sleeve can be obtained, which reduces the amount of water penetrating into the package and increases the anticorrosive protection of the metal product. To connect strips of anticorrosive packaging material, in continuous production, various welding or gluing methods are usually used.

The allowance size for joining strips is usually from 10 mm to 50 mm.

The use of anti-corrosion packaging material, made from a single sheet, allows us to obtain the following additional technical results:

improve the convenience of packaging a metal product and reduce the time it takes to package it by eliminating the need to use several strips of anti-corrosion packaging material;

reduce the consumption of anti-corrosion packaging material for packaging a single unit of metal product by reducing the number of overlapping joints of the longitudinal edges of the anti-corrosion material and the possibility of optimizing the width of the anti-corrosion packaging material.

The latter is achieved by the fact that for packaging, for example, rolls of flat rolled steel with an internal diameter of 600 mm, an external diameter of 1000 to 1500 mm and a steel strip width of 1250 mm, an anti-corrosion packaging material 3.6 m wide is required. Or three strips of anti-corrosion packaging material, each 1.5 m wide, can be used to wrap the said rolls.

Priority is given to a watertight continuous connection of strips of anti-corrosion packaging material. In some cases, discontinuous connection of strips of anti-corrosion packaging material is permitted, for example, to reduce the consumption of extruded additive (see below) for short shipment hauls (up to 1000 km) and short storage periods (up to 90 days). It is unacceptable for the materials used to connect the strips to have adhesion to the metal product and/or leave marks on the metal product.

Waterproof connection of strips of anticorrosive packaging material allows to minimize the amount of water getting to the metal product. With discontinuous connection of strips of anticorrosive packaging material, the amount of water getting to the metal product will be inversely proportional to the ratio of the length of the fastened sections of the strips to the length of the unfastened sections of the strips of anticorrosive packaging material. Thus, connection of strips of anticorrosive packaging material allows to increase the anticorrosive protection of metal products.

Usually, anticorrosive packaging material is produced in rolls. In most cases, the roll weight is from 100 kg to 500 kg. To increase the convenience of storage, transportation and use of anticorrosive packaging material (usually more than 2 m wide), it can be wound into a roll in a half-sleeve. To increase the reliability of anticorrosive protection of metal products, anticorrosive packaging material can be produced in a sleeve with subsequent winding into a roll. Other methods of laying anticorrosive packaging material are also possible.

Each consumer of anticorrosive packaging material usually has metal products of different dimensions, therefore anticorrosive packaging material is supplied in several standard sizes by width. Within the limits of application of anticorrosive packaging material of a certain width, there may be a range of dimensions of metal products requiring the use of anticorrosive packaging materials in sheets of different lengths, which are cut, for example, from a roll of anticorrosive packaging material. Such metal products may be, for example, rolls of flat rolled metal.

When selecting the parameters of anti-corrosion packaging material, it is necessary to take into account that

wrapping the bulky metal products in question in anti-corrosion packaging material is usually not hermetically sealed;

Anti-corrosion packaging material is usually protected from mechanical damage by additional external packaging elements (installed over the anti-corrosion packaging material), thus forming a multi-layer packaging system that is not load-bearing, therefore, all layers of the packaging and the metal product work together. For example, when packing a roll of flat rolled metal, polymer sheets 2-5 mm thick are installed on its forming surfaces. The end surfaces of the roll are protected by rings made of a polymer sheet 2-5 mm thick. The edges of the roll are covered with metal shells. Other elements of packaging of rolls of flat rolled metal can also be used.

During transportation and storage, metal products and multilayer packaging may be subject to mechanical impacts, including impacts. Metal products may have surfaces with protruding parts and/or relatively sharp edges and/or corners. In this case, damage to the integrity of the anti-corrosion packaging material is unacceptable. Destruction of the anti-corrosion packaging material usually occurs on protruding parts, edges or corners of metal products. The following factors help reduce the likelihood of damage to the integrity of the anti-corrosion packaging material:

the possibility of relative elongation of the second and first layers of anti-corrosion material by 20% or more in the longitudinal and transverse directions;

the possibility of shifting the second layer relative to the first layer in the longitudinal and transverse directions of the anti-corrosion packaging material.

The first layer of the polymer film of the anticorrosive packaging material usually has deliberately high relative elongation values (hundreds of percent). The second layer of the anticorrosive packaging material usually has a relative elongation value from several percent to 100%.

The first layer of polymer film and the second layer of fibrous material can be connected to each other in various ways. The extreme cases of layer connection are point and continuous connection.

Point bonding involves bonding the first and second layers in small areas of approximately 2-5 mm with a distance between areas of 50 to 300 mm. In this case, breaking the fibers of the fibrous material of the second layer in one or more places will weaken the tensile strength and/or tear strength of the anti-corrosion packaging material. In this case, the first layer of polymer film will be able to extend over the entire area between the bonding points where deformation occurs. In addition, under mechanical action, the layers in the gaps between the bonded areas can shift relative to each other, which significantly reduces the likelihood of damage to the integrity of the first layer of the anti-corrosion packaging material.

Point bonding of layers of anticorrosive packaging material can be used for all second layer materials used. This is especially relevant for second layers with minimal relative elongation values.

Continuous connection of layers of anticorrosive packaging material implies connection of layers over the entire area of their contact. In this case, part of the fibers of the second layer adjacent to the first layer is rigidly combined with the first layer of anticorrosive packaging material. Consequently, in the initial period of mechanical action on the anticorrosive packaging material, its tensile and/or tear strength is maximum, both layers of the anticorrosive packaging material are deformed equally. As elastic-plastic deformations of the anticorrosive packaging material develop, one of the layers with the minimum relative elongation (usually the second layer) begins to deteriorate. In this case, the first layer of the anticorrosive packaging material with a higher relative elongation value will be able to deform only in the area of destruction of the second layer, i.e. the absolute values of elongation will be minimal. Thus, a continuous connection of layers of anticorrosive packaging material for the tasks under consideration is advisable when using a second layer with a relative elongation in the longitudinal and transverse directions of at least 20% (obtained from the experience of practical application of anticorrosive packaging material). For anticorrosive packaging materials with high tensile strength, tearing (for example, three-layer anticorrosive packaging materials, see below) or for easy transportation and storage conditions, it is permissible to use layers with a minimum relative elongation of 5%.

In addition to point and continuous, dotted layer bonding and strip bonding can be used. They will have intermediate characteristics between point and continuous bonding, which will largely depend on the specific location of the anticorrosive packaging material (free or bonded) where the elongation occurs.

The connection of the second layer of anti-corrosion packaging material to the first layer of anti-corrosion packaging material is usually carried out in two ways:

lamination of the second layer of anti-corrosion packaging material with a polymer material;

joining the second layer of anti-corrosion packaging material and the first layer of finished polymer film (usually this is done using permanent adhesive or ultrasonic welding).

When laminating, the first layer can be made by applying a polymer melt directly to the second layer, for example, by contact or contactless flat-slot extrusion. In this case, polyolefins are usually used, for example, polyethylene, polypropylene, ethylene vinyl acetate or their combinations, polyvinyl chloride, polyethylene terephthalate can also be used. As a result, a two-layer laminated anticorrosive packaging material is obtained. According to their physical and mechanical properties, these anticorrosive packaging materials are classified as materials with a continuous connection of layers and make it possible to exclude the operation of applying an adhesive composition.

Currently, the production and application of anti-corrosion packaging materials made of laminated materials made of polymer fibers is rapidly developing. Materials are produced from laminated woven material or laminated non-woven material.

In the manufacture of anticorrosive packaging material from strips of laminated nonwoven material, laminated spunbond web made of polymer fibers is most widely used. In this case, the laminating layer is the first layer of the anticorrosive packaging material, and accordingly, the spunbond web made of polymer fibers is the second layer of the anticorrosive packaging material. Anticorrosive packaging material made of laminated spunbond web made of polymer fibers has fairly high values of relative elongation of layers (about 20-40% in the longitudinal and transverse directions), which allows using anticorrosive packaging material with a minimum surface density and, therefore, minimizing material consumption.

In the production of anti-corrosion packaging material from strips of laminated woven material, laminated woven polypropylene is most widely used. This material has relatively low values of relative elongation of layers, but significantly higher strength indicators, in particular for rupture and tearing (all other things being equal, compared to laminated non-woven material).

The maximum probability of mechanical (including impact) impacts on a packaged metal product, and consequently on the anti-corrosion packaging material, occurs during transportation, including during cargo handling. When selecting specific values of the surface density of the anti-corrosion packaging material and its layers, it is also necessary to take into account the storage conditions and loading and unloading operations.

For anti-corrosion packaging material made with lamination of the second layer, the value of the surface density of the first layer is selected as follows:

10-20 g/m² - for transportation by rail up to 1000 km or by road, or container transportation (hereinafter - simplified conditions);

20-30 g/m² - for transportation by rail in wagons over distances from 1000 km to 3000 km (hereinafter - average conditions);

30-50 g/m² - for shipments by rail with transshipment in ports and sea transportation (hereinafter - severe conditions).

The first layer can be a ready-made film made of polyethylene or polypropylene, or polyvinyl chloride, or oriented or amorphous polyethylene terephthalate, or multilayer films, two-layer, three-layer, which can consist of the same or different layers, etc.

For the first layer of finished polymer film, polymer films with the following surface density values are preferably used:

30-40 g/m² - for light conditions;

40-80 g/m² - for average conditions;

80-150 g/m² - for heavy conditions.

The second layer of anti-corrosion packaging material can be made from natural fibers: plant, animal and mineral origin; artificial or synthetic chemical fibers, as well as chemical fibers in combination with natural fibers.

Non-woven spunbond fabric made of polymer fibers and woven fabric made of polymer fibers have become widely used as the second layer of anti-corrosion packaging material.

Among nonwoven materials made of synthetic fibers, the most widely used as the second layer of anticorrosive packaging material is spunbond fabric made of polymer fibers (GOST 16430-83. Nonwoven fabrics: State standard of the USSR: date of introduction 1984-01-01/ USSR State Committee for Standards. - Official ed. - Moscow: Publishing house of standards, 1983. - 5 p.), which provides maximum physical and mechanical parameters with minimum surface density, withstands dynamic loads well, has high wear resistance and bending resistance. In combination with the ability to impart hydrophilic or hydrophobic properties to the fabric, the use of spunbond fabric made of polymer fibers allows for a high level of product protection.

Spunbond, spunbond-meltblown-spunbond (SMS) and thermobond - a group of materials based on endless fibers manufactured by the spinneret method and bonded by the point heat-fixation method - can be used as the second layer of anti-corrosion packaging material made of spunbond fabric made of polymer fibers. Single-layer, two-layer and three-layer spunbond are the most widely used for the tasks under consideration. In addition, SMS material is widely used, which consists of external layers of spunbond and an internal layer of meltblown.

The most widely used materials for the production of the second layer of anti-corrosion packaging material from spunbond fabric made from polymer fibers are non-woven materials made from polypropylene fibers.

The second layer of the anti-corrosion packaging material, made of a spunbond fabric made of polymer fibers, is usually made hydrophilic. This allows for the optimization of the application of corrosion inhibitors, as well as the most effective removal of moisture from the surface of the metal product. In the initial state, non-woven materials are hydrophobic. To impart hydrophilic properties, the second layer of the anti-corrosion packaging material is impregnated with surfactants. Surfactants are usually also added to the aqueous solution of corrosion inhibitors, which is introduced into the second layer of the anti-corrosion packaging material.

Thermal bonding of nonwoven material allows to significantly increase its physical and mechanical properties. Thermal bonding can be performed using hot rollers and passing the web between them. Thermal bonding can also be performed by passing the finished material through a thermal oven to heat the material and then passing it through rollers. In both cases, the rollers can be made smooth or with a pattern, for example, dots.

The surface density of the second layer of anti-corrosion packaging material made of spunbond fabric made of polymer fibers is selected from the range of 10-150 g/m², respectively:

from 10 g/m² to 30 g/m² - for light transportation conditions (materials less than 10 g/m² do not provide sufficient strength);

from 30 g/m² to 70 g/m² - for average transportation conditions;

from 70 g/m² to 150 g/m² - for heavy-duty transportation conditions.

The surface density of the second layer of anti-corrosion packaging material made of woven polypropylene is selected from the range of 30-80 g/m²:

from 30 g/m² to 45 g/m² - for light transportation conditions;

from 45 g/m² to 60 g/m² - for average transportation conditions;

from 60 g/m² to 80 g/m² - for heavy-duty transportation conditions.

As a rule, if anti-corrosion packaging material with a second layer of spunbond fabric made of polymer fibers with a surface density of 150 g/m², or with a second layer of woven polypropylene with a surface density of 80 g/m² does not provide the required level of protection for a metal product, it is recommended to change the external elements of the packaging, for example, to increase the thickness of the polymer sheets and rings that cover the forming and end surfaces of the flat rolled metal rolls, respectively.

The surface density of the anticorrosive packaging material with the second layer of spunbond fabric made of polymer fibers and the first layer of finished polymer film is usually from 50 g/m² to 200 g/m². When using laminated spunbond fabric made of polymer fibers, the surface density of the anticorrosive packaging material is usually selected from 30 g/m² to 170 g/m². When using laminated woven polypropylene, the surface density of the anticorrosive packaging material is usually selected from the range of 50-130 g/m².

The joining of the longitudinal edges of the strips of anticorrosive packaging material is carried out in motion in a continuous mode. The production of anticorrosive packaging material is a relatively large-scale serial production, therefore the joining of the edges of the strips of anticorrosive packaging material must be carried out in an automatic mode.

The total thickness of the layers of anticorrosive packaging material has relatively low values: approximately from 30 µm to 200 µm. The possible spread of values of the thickness of the polymer layers of anticorrosive packaging material is ± 30% of the nominal value.

The most suitable methods for joining the longitudinal edges of strips of anti-corrosion packaging material for the specified conditions are welding and/or gluing with thermoplastic adhesive.

During welding, the interface between the surfaces of polymers (thermoplastics) being joined disappears, turning into a diffuse transition layer. The strength of the connection is determined by the emerging forces of intermolecular interaction. The transition layer is formed as a result of the diffusion of polymer molecules, which occurs when the polymer transitions to a viscous-flowing state. This is realized when the materials being welded are heated.

Taking into account the above conditions, ultrasonic and extrusion welding methods are most widely used for joining the longitudinal edges of strips of anti-corrosion packaging material.

During ultrasonic welding, effects occur that lead to the occurrence of surface and intermolecular friction, resulting in heating of the surfaces being joined.

Extrusion welding is carried out by feeding molten filler material between the surfaces of the edges of the anti-corrosion packaging material to be joined. The filler material must be as close as possible to the material being joined in chemical composition, density and melt flow index and in its initial state can be in the form of a granule or threads wound on a spool.

For high-quality welding and/or gluing of polymer films, it is necessary to pre-treat their surface at the welding site with a corona device. Usually, the edges of the strips of anti-corrosion packaging material with a second layer of polymer fibers are connected between the second layers. In this case, corona treatment of the polymer fiber surface is not necessary.

When selecting welding modes, one of the critical parameters is the thickness of the material being joined. If the material is not heated enough (large thickness), the strength of the connection will decrease. In case of overheating (small thickness), the material is destroyed. The second layer of polymer fibers with minimum diameters melts first. The presence of two layers of anti-corrosion packaging material allows you to adjust the operating modes of the equipment so that the temperature of the second layer does not fall below the permissible value. In this case, with minimum values of the surface density of the second layer, the first layer is subject to destruction to a minimum degree and practically retains its physical and mechanical properties. Thus, the use of anti-corrosion packaging material with a second layer of polymer fibers allows you to increase the reliability of the connection of the longitudinal edges of the strips of anti-corrosion packaging material.

When joining the longitudinal edges of strips of anticorrosive packaging material with a hot-melt adhesive, an adhesive substance is used that can repeatedly melt when heated and harden when cooled. Typically, this is a series of thermoplastic polymeric materials based on ethylene vinyl acetate or polyamide. Hot-melt adhesives have low shrinkage, high mechanical strength and the ability to fill voids. The latter allows for additional strength when joining strips of anticorrosive packaging material between second layers of fibrous material.

In order to increase the anti-corrosion properties of the anti-corrosion packaging material, corrosion inhibitors are introduced into its second layer, which form a film (usually monomolecular) on the surface of the protected metal product. This film protects against oxidation reactions. Anti-corrosion packaging materials with corrosion inhibitors are widely used, for example, to protect ferrous metals.

As corrosion inhibitors, contact and volatile corrosion inhibitor compositions are usually used, but volatile and contact corrosion inhibitors can also be used separately. Contact corrosion inhibitors, as a rule, work effectively in protecting simple-shaped articles (cylinder, parallelepiped, etc.), when the anticorrosive packaging material contacts the surface of the article. Volatile corrosion inhibitors are especially effective in protecting articles with a complex shape or cavities, such as pipes, tanks, etc. The most widely used corrosion inhibitor compositions in anticorrosive packaging materials are those that can simultaneously combat corrosion by both contact and volatile methods. The use of inhibitor compositions is especially effective in protecting multilayer articles, such as rolls and packs of metal, bundles of pipes, etc., as well as for protecting articles of complex shape. The most common substances are sodium nitrite, urotropine, benzotriazole, cyclohexylamine salts, sodium benzoate, monoethanolamine salts, hexamethyleneimine meta-nitrobenzoate. In addition, other substances can be used, such as those from amine groups, guanidine, morpholine, dimethylformamide, orthonitrophenol, triethylamine dinitronaphthalate, adduct of orthonitrophenol, benzotriazole, cyclohexylamine, sodium oleate and others.

The composition and quantity of corrosion inhibitors used depends on the metals that need to be protected, the shape of the metal products, the conditions of transportation and storage of the metal products, the required duration of protection, etc. Typically, the quantity of corrosion inhibitors introduced into the second layer of anti-corrosion packaging material ranges from 0.5 g/m² to 20 g/m².

For the considered tasks of anticorrosive protection of metal products, the most widely used is the introduction of corrosion inhibitors from a solution into the second fibrous layer of the anticorrosive packaging material, followed by its drying. In some cases, for example, for metal products with existing anticorrosive protection, corrosion inhibitors can be introduced directly into the polymer material of one of the layers.

For metal products with existing corrosion protection, such as ferrous metal with a polymer coating, anticorrosive packaging materials without corrosion inhibitors can be used. The specified metal products have a sufficiently high degree of corrosion protection. Based on existing experience, for these products it is necessary to limit water access to the metal product (implemented by the first layer) and ensure water drainage from the surface of the protected metal product (implemented by the second layer within the limits of its ability to operate).

In order to increase the strength properties of the anti-corrosion packaging material, a reinforcing layer can be additionally introduced, which is connected to the first layer of polymer film from the side of the first layer opposite to that from which the first layer is connected to the second layer.

The most widely used reinforcing layer is woven polypropylene fabric, which has high physical and mechanical properties and is relatively inexpensive. The surface density of the additional reinforcing layer is usually from 30 g/m² to 150 g/m².

The most widely used are anticorrosive packaging materials with a reinforcing layer, consisting of a layer of spunbond fabric made of polymer fibers (second layer), a laminating layer (first layer) and an additional reinforcing layer of woven polypropylene. In this case, the laminating layer is simultaneously a binder with the second layer and with an additional reinforcing layer. In the further text of the description, this material will be called an anticorrosive packaging material with an additional reinforcing layer.

The surface density of anti-corrosion packaging material with an additional reinforcing layer is usually from 50 g/m² to 300 g/m² respectively:

from 50 g/m² to 80 g/m² - for light transportation conditions;

from 80 g/m² to 160 g/m² - for average transportation conditions;

from 160 g/m² to 300 g/m² - for heavy-duty transportation conditions.

In order to improve the sealing properties of the anti-corrosion packaging material, an additional barrier layer can be introduced, which is connected to the second layer on the side opposite to that on which the first layer of the anti-corrosion packaging material is located.

The additional barrier layer is similar to the first layer of the anti-corrosion packaging material in its composition, methods of connection with the second layer and surface density. The most widely used additional barrier layer is made by laminating the second layer. In case of damage to the integrity of one of the layers (the first or barrier), it will not lead to the possibility of water penetration to the metal product. In case of damage to the integrity of the first layer in one place of the anti-corrosion packaging material and damage to the integrity of the additional barrier layer in another place of the anti-corrosion packaging material, the possibility of water penetration to the metal product will be significantly limited.

Among anticorrosive packaging materials with an additional barrier layer, the most widely used materials are those consisting of a laminating layer (first layer), woven polypropylene (second layer) and an additional laminating layer (additional barrier layer). In the further text of the description, this material will be called an anticorrosive packaging material with an additional barrier layer.

The surface density of anti-corrosion packaging material with an additional barrier layer is usually from 50 g/m² to 200 g/m².

Anti-corrosion packaging materials with additional layers (reinforcing or barrier) are usually used for medium and heavy-duty transportation conditions.

According to the utility model, the anticorrosive packaging material works as follows. The metal product is wrapped with the anticorrosive packaging material of the required width and length. In most cases, the second layer is adjacent to the metal product. When water gets on the packed metal product, the first layer of the anticorrosive packaging material prevents water from penetrating the metal product. In practice, some of the water gets to the metal product. In this case, the second layer of the anticorrosive packaging material absorbs the leaked water within its capabilities. When using the anticorrosive packaging material with a second layer made of woven polypropylene, schemes can be used when the first layer of the anticorrosive packaging material is adjacent to the metal product. In this case, the second layer of the anticorrosive packaging material, made of woven polypropylene, protects the first layer from through destruction and, therefore, more reliably protects the metal product from water ingress. As a rule, the above measures are sufficient for reliable protection of galvanized metal products or products with polymer or other anti-corrosion coatings under light and medium transportation conditions.

To improve anti-corrosion protection, anti-corrosion packaging materials with corrosion inhibitors are used. Corrosion inhibitors interact with the protected metal to form a thin protective layer on the metal surface that effectively slows down corrosion, so even moisture getting inside the product's packaging does not cause its oxidation within the limits of the corrosion inhibitors' ability to act. The amount and composition of corrosion inhibitors are selected depending on the type of metal, transportation and storage conditions of the metal product.

When using anticorrosive packaging material with a second layer of spunbond fabric made of polymer fibers, corrosion inhibitors are usually introduced into the second layer of the anticorrosive packaging material. When using anticorrosive packaging material with a second layer of woven polypropylene, in many cases, corrosion inhibitors are introduced directly into the polymer material of the first layer of the anticorrosive packaging material. Other options for making anticorrosive packaging materials with corrosion inhibitors are also possible. It is advisable to arrange the layer of the anticorrosive packaging material into which the corrosion inhibitors are introduced so that it (the layer with corrosion inhibitors) adjoins the metal product.

Evidence of the feasibility of implementing the utility model is presented using examples of various designs of anti-corrosion packaging material, widely used in packaging flat rolled steel products.

Three strips were taken, each of which was wound into a roll, from laminated spunbond containing the first layer of polypropylene with a surface density of 20 g/m² and the second layer made of polypropylene fibers, having a surface density of 35 g/m², including corrosion inhibitors in the amount of 5 g/m², and the width of the strips was 1.5 m, 1.5 m and 0.75 m. The strips were connected to each other along their longitudinal edges between the second layers by welding with an extrudable additive made of polypropylene to form waterproof seams. As a result, an anti-corrosion packaging material was obtained in the form of a web 3.6 m wide, wound into a roll in a half-sleeve, with a surface density of 60 g/m². This anti-corrosion packaging material can be used, for example, for packaging flat rolled metal products with a diameter of 1.0 to 1.5 m or packs of flat rolled metal products.

We took 3 rolls of finished polyethylene film with a surface density of 50 g/m², 1.5 m wide each, and three rolls of spunbond made of polypropylene fibers with a surface density of 40 g/m². A strip of finished film (the first layer of the anti-corrosion packaging material) was connected to a strip of spunbond (the second layer of the anti-corrosion packaging material). The connection was made pointwise using hot-melt adhesive with residual stickiness. We obtained three strips of two-layer anti-corrosion packaging material, 1.5 m wide each, wound into three rolls. The resulting strips were connected to each other along the longitudinal edges between the second layers using ultrasonic welding to form waterproof seams. The result was an anti-corrosion packaging material in the form of a 4.3 m wide sheet with a surface density of 90 g/m² without corrosion inhibitors. This anti-corrosion packaging material can be used, for example, for packaging galvanized steel rolls with large external diameters from 1.5 m to 2.0 m.

We took two strips, each rolled into a roll, made of laminated woven polypropylene containing the first layer of polypropylene copolymer with a surface density of 25 g/m². The first layer was infused with corrosion inhibitors in an amount of 10 g/m². The second layer of woven polypropylene had a surface density of 60 g/m². The width of the strips was 1.5 and 0.5 m. We connected the strips along their longitudinal edges between the second layers using ultrasonic welding to form a waterproof seam. As a result, we obtained an anticorrosive packaging material in the form of a 1.9 m wide sheet rolled into a roll with a surface density of 95 g/m². This anticorrosive packaging material can be used for packaging, for example, bundles of metal rods.

We took two strips of three-layer material, each 1.5 m wide, wound into two rolls. The three-layer material contains a spunbond layer with a surface density of 25 g/m², made of polypropylene fibers (the second layer of the anti-corrosion packaging material), containing corrosion inhibitors in the amount of 3-5 g/m², a laminating layer with a surface density of 20 g/m², made of polypropylene copolymer (the first layer of the anti-corrosion packaging material) and a third layer with a surface density of 50 g/m², made of woven polypropylene (additional reinforcing layer of the anti-corrosion packaging material). The layers of the anti-corrosion packaging material with an additional reinforcing layer are monolithically connected to each other by a laminating layer. The strips of three-layer material were connected to each other along their longitudinal edges between additional layers of woven polypropylene using thermoplastic glue applied in discontinuous strips. An anti-corrosion packaging material was obtained in the form of a 2.9 m wide sheet with a surface density of 100 g/m² with a permeable seam. This anti-corrosion packaging material can be used, for example, for packaging bundles of pipes. When the permeable seam is located at the bottom of the bundle of pipes, water that has leaked into the package will be able to escape.

We took 3 strips of three-layer material, 1.5 m wide each, wound into three rolls, and one strip of three-layer material, 0.5 m wide, wound into a roll. The three-layer material comprises a first laminating layer with a surface density of 30 g/m², made of polypropylene containing corrosion inhibitors in an amount of 5-8 g/m², a layer of woven polypropylene (the second layer of anti-corrosion packaging material with a surface density of 70 g/m², and a third, additional sealing layer with a surface density of 30 g/m², made of polypropylene. The layers of the three-layer material are monolithically connected to each other. The strips of the three-layer material were connected to each other along their longitudinal edges between the first layers of polypropylene with a double seam. One seam was made by welding with an extruded polypropylene additive, the second seam was made by ultrasonic welding. The distance between the seams was 5 mm. Both seams were made waterproof. An anti-corrosion packaging material with a surface density of 135 g/m² was obtained, with an additional sealing layer, in the form of 4.9 m wide web, rolled into a roll in a half-sleeve. This anti-corrosion packaging material can be used, for example, for packaging metal structures.

Thus, the utility model provides for the expansion of the arsenal of anti-corrosion packaging materials, providing for an increase in the level of anti-corrosion protection of metal products, due to the creation of an anti-corrosion packaging material made in one sheet with the width required for packaging a metal product.

Claims (3)

1. An anti-corrosion packaging material for large-sized metal products, comprising a first layer made of polymer film and a second layer made of fibrous material, connected to each other, characterized in that it is a web of strips connected to each other along the longitudinal edges. 2. An anti-corrosion packaging material according to paragraph 1, characterized in that it additionally contains a reinforcing layer connected to the first layer on the side opposite to that from which the first layer is connected to the second layer. 3. An anti-corrosion packaging material according to claim 1, characterized in that it additionally contains a barrier layer connected to the second layer on the side opposite to that from which the second layer is connected to the first layer.