PL249433B1 - Self-healing laminate and method of producing it - Google Patents

Abstract

The subject of the application is a self-healing laminate, which is characterized in that in the central part of the laminate there is a layer of polyurethane foam (4) with a thickness of 10 mm to 50 mm, to both surfaces of which two identical self-healing layers (5), each with a thickness of 0.4 mm to 2.5 mm, consisting of glass fibers filled with isophorone diisocyanate and bonded with epoxy resin, adhere. Two identical layers of epoxy-carbon composite (6), each with a thickness of 0.2 mm to 1 mm, adhere adhesively to the outer surfaces of the outer self-healing layers (5). The application also covers a method of producing a self-healing laminate, which consists in applying a sol-gel layer (3) of 1 µm to 3 µm thick to two sheets (1) of aluminium alloy with a thickness of 0.3 mm to 1 mm and having a ceramic layer (2) of 6 µm to 12 µm thick on both surfaces, and then leaving it for 1 hour at a temperature of 23°C. Then, on one of the sheets (1) made of an aluminum alloy with a thickness of 0.3 mm to 1 mm and having on both surfaces a ceramic layer (2) with a thickness of 6 µm to 12 µm and a sol-gel layer (3) with a thickness of 1 µm to 3 µm, two sheets of carbon prepreg in the form of a fabric with a thickness of 0.2 mm to 1 mm are successively applied, thus obtaining two identical layers of an epoxy-carbon composite (6) with a thickness of 0.2 mm to 1 mm each. Two identical layers of glass fibres filled with isophorone diisocyanate, each from 0.25 mm to 2 mm thick, are then applied successively, each layer of glass fibres being laminated manually with epoxy resin to obtain two identical self-healing layers (5) each from 0.4 mm to 2.5 mm thick, consisting of glass fibres filled with isophorone diisocyanate and bonded with epoxy resin.

Description

The subject of the invention is a self-healing laminate and a method of manufacturing a self-healing laminate.

Metal-fiber laminates used in the Airbus A380 are becoming increasingly popular not only in the aerospace industry, but also in the railway and automotive industries. The most desirable metal-fiber laminates in terms of properties are aluminum-based laminates with epoxy layers and glass fibers, called Glare®. New technological and material solutions are constantly sought, aiming to make materials lighter while maintaining similar or better properties. In the aerospace industry, where fuel costs are high, new structures are constantly being developed to achieve greater range while minimizing costs and maintaining specific environmental standards.

A composite laminate with a self-healing layer is known and used from the US patent application No. US20130209764 A1, in which the composite structure comprises a plurality of layers of composite material and at least one layer of self-healing material.

From the article entitled "Microcapsules in Fiber Metal Laminates for Self-Healing at the Interface between Magnesium and Carbon Fiber-Reinforced Epoxy", M. Ostapiuk knows about a metal-fiber laminate with a layer of magnesium and carbon fibers and containing microcapsules in the aspect of self-healing properties at the interface.

In the article entitled “Recovery of Mode I self-healing interlaminar fracture toughness of fiber metal laminate by modified double cantilever beam test”, L. Shanmugam, M. Naebe, J.K. Russell, J. Varley and J. Yang in Composites Communications Volume 16, December 2019, Pages 25-29, a metal-fiber laminate consisting of thin metal sheets and a self-healing polymer layer and a polymer layer containing carbon fibers was presented.

From the article entitled "The interlaminar resistance of carbon fiber-Al laminate reinforced with hollow and core-shell microcapsules" M.D. Shokrian, K. Shelesh-Nezhad, R. Najjar IE. Bigdeli Theoretical and Applied Fracture Mechanics Volume 110, December 2020, 102778 metal-fiber laminates based on aluminum and carbon composite containing carbon fibers are known, where a layer of microcapsules is used as a self-healing layer.

The aim of the invention is to produce a self-healing laminate resistant to impact and corrosion for use in the automotive and aviation industries.

The essence of the self-healing laminate, which has an aluminum alloy sheet on the outer side, with a ceramic layer with a sol-gel layer applied to both surfaces, according to the invention, is that the central portion of the laminate contains a layer of polyurethane foam ranging from 10 mm to 50 mm thick. Two identical self-healing layers, each ranging from 0.4 mm to 2.5 mm thick, consisting of glass fibers filled with isophorone diisocyanate and bonded with epoxy resin, adhere to both surfaces of the polyurethane foam layer. Two identical layers of epoxy-carbon composite, each ranging from 0.2 mm to 1 mm thick, adhere to the outer surfaces of the outermost self-healing layers. In contrast, a 1 μm to 3 μm thick sol-gel layer adheres to the outer surfaces of the outermost layers of the epoxy-carbon composite, which is applied to a 6 μm to 12 μm thick ceramic layer on a 0.3 mm to 1 mm thick aluminum alloy sheet. The aluminum alloy sheet has a 6 μm to 12 μm thick ceramic layer on the outer surface, with a 1 μm to 3 μm thick sol-gel layer applied.

The essence of the method for manufacturing a self-healing laminate according to the invention is that a 1 μm to 3 μm thick sol-gel layer is applied on both sides to two 0.3 mm to 1 mm thick aluminum alloy sheets having a 6 μm to 12 μm thick ceramic layer on both surfaces, and then left for 1 hour at 23°C. Then, two 0.2 mm to 1 mm thick sheets of carbon prepreg in the form of a fabric are applied successively to one of the 0.3 mm to 1 mm thick aluminum alloy sheets having a 6 μm to 12 μm thick ceramic layer and a 1 μm to 3 μm thick sol-gel layer on both surfaces, to obtain two identical layers of 0.2 mm to 1 mm thick epoxy carbon composite. Next, two identical layers of isophorone diisocyanate-filled glass fibers, each 0.25 mm to 1 mm thick, are applied successively. Each layer of glass fibers is hand-laminated with epoxy resin, resulting in two identical, self-healing layers, each 0.4 mm to 2.5 mm thick, consisting of isophorone diisocyanate-filled glass fibers bonded with epoxy resin. A sheet of polyurethane foam, 10 mm to 50 mm thick, is then applied, resulting in a 10 mm to 50 mm thick layer of polyurethane foam. Next, two identical layers of isophorone diisocyanate-filled glass fibers, each 0.25 mm to 2 mm thick, are applied sequentially. Each layer of glass fibers is hand-laminated with epoxy resin, resulting in two identical self-healing layers, each 0.4 mm to 2.5 mm thick, consisting of isophorone diisocyanate-filled glass fibers bonded with epoxy resin. Two sheets of carbon prepreg fabric, 0.2 mm to 1 mm thick, are then applied sequentially, resulting in two identical layers of epoxy-carbon composite, each 0.2 mm to 1 mm thick. Next, a second sheet of 0.3 mm to 1 mm thick aluminum alloy sheet is applied, with a 6 μm to 12 μm ceramic layer and a 1 μm to 3 μm sol-gel layer on both surfaces. A vacuum pack is then applied and the air is evacuated to a negative pressure of -0.08 MPa. The entire assembly is then cured for 4 hours at 135°C and 4 bar.

It is advantageous to apply two sheets of carbon prepreg in the form of a twill or satin weave fabric in succession.

It is advantageous to apply two identical layers of glass fibres filled with isophorone diisocyanate in succession in the orientation 0°/0° or 0°/90° or +45°/-45°.

A beneficial effect of the invention is that it creates a self-healing laminate with high resistance and absorption properties against low-velocity impacts. The resulting laminate also possesses anti-corrosion properties. A layer containing glass fibers filled with a self-healing agent inhibits the development of cracks in the laminate, and after 24 hours, the laminate is self-healed. Furthermore, the polyurethane foam layer additionally acts as an absorbent layer against impacts.

The invention is presented in an embodiment in the drawing, which shows a cross-section of the laminate.

Example 1

The method for producing the self-healing laminate involved cleaning and degreasing the surfaces of 300 x 400 mm, 0.3 mm thick AlCu4Mgl alloy sheet 1 in the T3 temper in the following manner: 300 x 400 mm, 0.3 mm thick, 300 x 400 mm thick AlCu4Mgl alloy sheet ¹ in the T3 temper in the following manner: ... A 6 μm thick ceramic layer 2 was obtained on both surfaces of sheet metal 1 made of AlCu4Mgl alloy. A 1 μm thick sol-gel layer 3 was applied by hand lamination to the sheets 1 made of AlCu4Mgl alloy with a 6 μm thick ceramic layer 2 on both surfaces and left for 1 h at 23°C. Then, two sheets of carbon prepreg in the form of a 0.2 mm thick twill weave fabric were successively applied to one of the 0.3 mm thick AlCu4Mgl alloy sheets with a 6 μm thick ceramic layer 2 and a 1 μm thick sol-gel layer 3, thus obtaining two identical layers of epoxy-carbon composite 6 with a thickness of 0.2 mm each. Two identical layers of glass fibers filled with isophorone diisocyanate, each 0.25 mm thick, were then applied successively in a 0°/0° orientation, with each layer of glass fibers being hand laminated with epoxy resin to obtain two identical self-healing layers 5, each 0.4 mm thick, consisting of glass fibers filled with isophorone diisocyanate and bonded with epoxy resin. A 10 mm thick sheet of polyurethane foam was then applied to obtain a 10 mm thick layer of polyurethane foam 4. Then, two identical layers of glass fibers filled with isophorone diisocyanate, each 0.25 mm thick, were successively applied in a 0°/0° orientation, each layer of glass fibers being manually laminated with epoxy resin to obtain two identical self-healing layers 5, each 0.4 mm thick, consisting of glass fibers filled with isophorone diisocyanate and bonded with epoxy resin.

Next, two sheets of 0.2 mm thick carbon prepreg fabric in a twill weave were successively applied, creating two identical layers of 0.2 mm thick epoxy-carbon composite 6. This was followed by the application of a second sheet of 0.3 mm thick AlCu4Mgl alloy 1 with a 6 μm thick ceramic layer 2 and a 1 μm thick sol-gel layer 3 on both surfaces. A vacuum pack was then created and the air was evacuated to a negative pressure of -0.08 MPa. The entire assembly was then cured for 4 hours at 135°C and 4 bar. 3M EC-2333 sol-gel was also used in the production of the self-healing laminate.

In the produced self-healing laminate, the central part contains a 10 mm thick layer of polyurethane foam 4, to both surfaces of which two identical self-healing layers 5, each 0.4 mm thick, consisting of glass fibers filled with isophorone diisocyanate and bonded with epoxy resin, adhere. Two identical layers of epoxy-carbon composite 6, each 0.2 mm thick, adhesively adhere to the outer surfaces of the outer self-healing layers 5. On the other hand, a 1 μm thick sol-gel layer 3 adheres adhesively to the outer surfaces of the extreme layers of the epoxy-carbon composite 6, which is applied to a 6 μm thick ceramic layer 2 located on a 0.3 mm thick sheet metal 1 made of an AlCu4Mgl alloy in the T3 state, which has a 6 μm thick ceramic layer 2 on its outer surface with a 1 μm thick sol-gel layer 3 applied thereto.

The resulting laminate was subjected to low-velocity impact testing, where self-healing properties were observed after 24 hours, restoring structural integrity. The laminate was subjected to low-velocity impact testing at impact speeds below 5 m/s and energy of 2.5 J. The laminate was characterized by the destruction of the glass fiber layer upon impact, while the polyurethane foam layer stopped the crack growth to the underside of the laminate. Furthermore, the laminates demonstrated increased resistance to environmental factors, particularly corrosion in NaCl solution.

Example 2

The self-healing laminate was manufactured by cleaning and degreasing the surfaces of 300 x 400 mm, 0.5 mm thick AlCu4Mgl alloy sheet 1 in the T3 temper using an alkaline solution of 5% sodium silicate by weight and 95% water at pH 10. The alkaline solution was then anodized for 10 minutes at a current density of 5 A/ ^dm2 at a voltage of up to 400 V, a high-frequency pulse current of 1000 Hz, and a 30% pulse duty cycle. The anodizing solution consisted of 5 g/l NaOH and 10 g/l Na2SiO3. The alkaline solution was then rinsed in tap water and dried with compressed air. An 8 μm thick ceramic layer 2 was obtained on both surfaces of sheet metal 1 made of AlCu4Mgl alloy. A 2 μm thick sol-gel layer 3 was applied by hand lamination to sheets 1 made of AlCu4Mgl alloy with an 8 μm thick ceramic layer 2 on both surfaces and left for 1 h at 23°C. Then, two sheets of carbon prepreg in the form of a 0.5 mm thick twill weave fabric were successively applied to one of the 0.5 mm thick AlCu4Mgl alloy sheets with an 8 μm thick ceramic layer 2 and a 2 μm thick sol-gel layer 3, thus obtaining two identical layers of epoxy-carbon composite 6, each 0.5 mm thick. Two identical layers of glass fibers filled with isophorone diisocyanate, each 1 mm thick, were then applied successively in a 0/90° orientation. Each layer of glass fibers was hand laminated with epoxy resin to obtain two identical self-healing layers 5, each 1.5 mm thick, consisting of glass fibers filled with isophorone diisocyanate and bonded with epoxy resin. A 25 mm thick sheet of polyurethane foam was then applied to obtain a 25 mm thick layer of polyurethane foam 4. Then, two identical layers of glass fibers filled with isophorone diisocyanate were successively applied in a 0/90° orientation, each 1 mm thick, wherein each layer of glass fibers was manually laminated with epoxy resin, to obtain two identical self-healing layers 5, each 1.5 mm thick, consisting of glass fibers filled with isophorone diisocyanate and bonded with epoxy resin. Then, two sheets of carbon prepreg in the form of a twill weave fabric, 0.5 mm thick, were successively applied, to obtain two identical layers of epoxy-carbon composite 6, each 0.5 mm thick, after which the second sheet of sheet 1 made of AlCu4Mgl alloy, with a thickness of

0.5 mm thick, with an 8 µm-thick ceramic layer 2 and a 2 µm-thick sol-gel layer 3 on both surfaces. A vacuum package was then prepared and the air was evacuated to a negative pressure of -0.08 MPa. The entire assembly was then subjected to a 4-hour curing process at 135°C and 4 bar pressure. 3M EC-2333 sol-gel was also used in the production of the self-healing laminate.

The self-healing laminate produced comprises a 25 mm thick polyurethane foam layer 4 in the central part, to both surfaces of which two identical self-healing layers 5, each 1.5 mm thick, consisting of glass fibers filled with isophorone diisocyanate and bonded with epoxy resin, adhere. Two identical layers of epoxy-carbon composite 6, each 0.5 mm thick, adhere adhesively to the outer surfaces of the outer self-healing layers 5. On the other hand, to the outer surfaces of the extreme layers of the epoxy-carbon composite 6 there is an adhesive layer of sol-gel 3 of thickness 2, which is applied to an 8 um thick ceramic layer 2 located on a sheet of metal 1 made of AlCu4Mgl alloy in the T3 state of 0.5 mm thickness, which on the outer surface has an 8 um thick ceramic layer 2 with a 2 um thick sol-gel layer 3 applied thereto.

The resulting laminate was subjected to low-velocity impact testing, where self-healing properties were observed after 24 hours, restoring structural integrity. The laminate was subjected to low-velocity impact testing at speeds below 5 m/s and energy of 5 J. The laminate was characterized by the destruction of the glass fiber layer upon impact, while the polyurethane foam layer stopped the crack growth to the underside of the laminate. Furthermore, the laminates demonstrated increased resistance to environmental factors, particularly corrosion in NaCl solution.

Example 3

The self-healing laminate was manufactured by cleaning and degreasing the surfaces of 300 x 400 mm, 1 mm thick AlCu4Mgl alloy sheets in the T3 temper in the form of sheet metal (1) in a 95% pH 10 solution with 5% sodium silicate by weight and 10% water by weight. The sheets were then anodized in an alkaline solution. The entire process took 10 minutes, and the current density was 5 A/ ^dm2 at a voltage of up to 400 V, with a high-frequency pulse current of 1000 Hz and a 30% pulse duty cycle. The anodizing solution consisted of 5 g/l NaOH and 10 g/l Na2SiO3. The samples were then rinsed in tap water and dried with compressed air. A 12 µm thick ceramic layer 2 was obtained on both surfaces of sheet metal 1 made of AlCu4Mgl alloy. A 3 µm thick sol-gel layer 3 was applied by hand lamination to the sheets 1 made of AlCu4Mgl alloy with a 12 µm thick ceramic layer 2 on both surfaces and left for 1 h at 23°C. Then, two sheets of carbon prepreg in the form of a 1 mm thick satin weave fabric were successively applied to one of the 1 mm thick sheets of sheet metal made of AlCu4Mgl alloy with a 12 µm thick ceramic layer 2 and a 3 µm thick sol-gel layer 3, thus obtaining two identical layers of epoxy-carbon composite 6 with a thickness of 1 mm each. Two identical layers of glass fibers filled with isophorone diisocyanate, each 2 mm thick, were then applied successively in a +45°/-45° orientation, each glass fiber layer being hand laminated with epoxy resin to obtain two identical self-healing layers 5, each 2.5 mm thick, consisting of glass fibers filled with isophorone diisocyanate and bonded with epoxy resin. A 50 mm thick sheet of polyurethane foam was then applied to obtain a 50 mm thick layer of polyurethane foam 4. Next, two identical layers of glass fibers filled with isophorone diisocyanate, each 2 mm thick, were successively applied in the +45°/-45° orientation, with each glass fiber layer being hand laminated with epoxy resin, to obtain two identical self-healing layers 5, each 2.5 mm thick, consisting of glass fibers filled with isophorone diisocyanate and bonded with epoxy resin. Next, two sheets of carbon prepreg in the form of a satin weave fabric, 1 mm thick, were successively applied, to obtain two identical layers of epoxy-carbon composite 6, each 1 mm thick. Afterwards, the second sheet 1 of AlCu4Mgl alloy, 1 mm thick, was applied, having on both surfaces a 12 µm thick ceramic layer 2 and a 3 µm thick solgel layer 3. Next, a vacuum package was created and the air was extracted to a negative pressure of -0.08 MPa. The entire assembly was then cured for 4 hours at 135°C and 4 bar pressure. Simultaneously, 3M EC-2333 sol-gel was used to produce the self-healing laminate.

The self-healing laminate produced comprises a 50 mm thick polyurethane foam layer 4 in the central part, to both surfaces of which two identical self-healing layers 5, each 2.5 mm thick, consisting of glass fibers filled with isophorone diisocyanate and bonded with epoxy resin, adhere. Two identical layers of epoxy-carbon composite 6, each 1 mm thick, adhere adhesively to the outer surfaces of the outer self-healing layers 5. On the other hand, a 3 μm thick sol-gel layer 3 adheres adhesively to the outer surfaces of the extreme layers of the epoxy-carbon composite 6, which is applied to a 12 μm thick ceramic layer 2 located on a 1 mm thick sheet metal 1 made of an AlCu4Mgl alloy in the T3 state, which has a 12 μm thick ceramic layer 2 on its outer surface with a 3 μm thick sol-gel layer 3 applied thereto.

The resulting laminate was subjected to low-velocity impact testing, where self-healing properties were observed after 24 hours, restoring structural integrity. The laminate was subjected to low-velocity impact testing at speeds below 5 m/s and energy of 10 J. The laminate was characterized by the destruction of the glass fiber layer upon impact, while the polyurethane foam layer stopped the crack growth to the underside of the laminate. Furthermore, the laminates demonstrated increased resistance to environmental factors, particularly corrosion in NaCl solution.

Claims (7)

1. A self-healing laminate having on its outer side a sheet metal (1) made of an aluminum alloy, which has on both surfaces a ceramic layer (2) with a sol-gel layer (3) applied thereto, characterized in that in the central part of the laminate there is a layer of polyurethane foam (4) with a thickness of 10 mm to 50 mm, to both surfaces of which two identical self-healing layers (5) with a thickness of 0.4 mm to 2.5 mm each, consisting of glass fibers filled with isophorone diisocyanate and bonded with epoxy resin, wherein to the outer surfaces of the outermost layers of the self-healing layers (5) adhere adhesively two identical layers of an epoxy-carbon composite (6) with a thickness of 0.2 mm to 1 mm each, while to the outer surfaces of the outermost layers of the epoxy-carbon composite (6) adhere adhesively a layer of a sol-gel layer (3) with a thickness of 0.4 mm to 2.5 mm each, 1 μm to 3 μm thick, which is applied to a ceramic layer (2) 6 μm to 12 μm thick located on a sheet metal (1) made of an aluminium alloy 0.3 mm to 1 mm thick, which on the outer surface has a ceramic layer (2) 6 μm to 12 μm thick with a sol-gel layer (3) 1 μm to 3 μm thick applied. 2. A method for producing a self-healing laminate characterized in that a sol-gel layer (3) of 1 μm to 3 μm thick is applied on both sides of two sheets (1) of aluminum alloy with a thickness of 0.3 mm to 1 mm and a ceramic layer (2) of 6 μm to 12 μm thick on both surfaces, and then left for 1 hour at 23°C, then two sheets of carbon prepreg in the form of a fabric of 0.2 mm to 1 mm thick are applied successively on one of the sheets (1) of aluminum alloy with a thickness of 0.3 mm to 1 mm and a ceramic layer (2) of 6 μm to 12 μm thick on both surfaces and a sol-gel layer (3) of 1 μm to 3 μm thick on both surfaces, and two identical layers of an epoxy-carbon composite are obtained. (6) with a thickness of 0.2 mm to 1 mm each, followed by subsequent application of two identical layers of glass fibres filled with isophorone diisocyanate with a thickness of 0.25 mm to 2 mm each, wherein each layer of glass fibres is laminated by hand with epoxy resin to obtain two identical self-healing layers (5) with a thickness of 0.4 mm to 2.5 mm each, consisting of glass fibres filled with isophorone diisocyanate and bonded with epoxy resin, then a sheet of polyurethane foam with a thickness of 10 mm to 50 mm is applied to obtain a layer of polyurethane foam (4) with a thickness of 10 mm to 50 mm ... PL 249433 Β1 identical layers of glass fibres filled with isophorone diisocyanate of a thickness of 0.25 mm to 2 mm each, wherein each layer of glass fibres is laminated manually with epoxy resin, and two identical self-healing layers (5) of a thickness of 0.4 mm to 2.5 mm each are obtained, consisting of glass fibres filled with isophorone diisocyanate and bonded with epoxy resin, then two sheets of carbon prepreg in the form of a fabric of a thickness of 0.2 mm to 1 mm are applied successively, and two identical layers of epoxy-carbon composite (6) of a thickness of 0.2 mm to 1 mm each are obtained, after which the second sheet (1) of aluminium alloy of a thickness of 0.3 mm to 1 mm is applied, having on both surfaces a ceramic layer (2) of a thickness of 6 μπι to 12 μπι and a sol-gel layer (3) with a thickness of 1 μπι to 3 μπι, then a vacuum package is made and the air is sucked out to a negative pressure of -0.08 MPa, after which the whole is subjected to a curing process for 4 hours at a temperature of 135°C and a pressure of 4 bar. 3. A method according to claim 2, characterized in that two sheets of carbon prepreg in the form of a twill weave fabric are applied successively. 4. A method according to claim 2, characterized in that two sheets of carbon prepreg in the form of a satin weave fabric are applied successively. 5. A method according to any one of claims 2 to 4, characterized in that two identical layers of glass fibers filled with isophorone diisocyanate are applied successively in an orientation of 070°. 6. A method according to any one of claims 2 to 4, characterized in that two identical layers of glass fibers filled with isophorone diisocyanate are applied successively in an orientation of 0790°. 7. A method according to any one of claims 2 to 4, characterized in that two identical layers of glass fibers filled with isophorone diisocyanate are applied successively in the orientation direction +457-45°.