Patent Publication Number: US-2022227111-A1

Title: Component with bonded thermoplastic and thermoset layers

Description:
This application is a divisional of U.S. patent application Ser. No. 16/131,939 filed Sep. 14, 2018 which is hereby incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     This disclosure relates generally to composite bodies and, more particularly, to polymer composite bodies and methods for forming such bodies. 
     2. Background Information 
     Various types and configurations of polymer composite bodies are known in the art. Such known composite bodies may include only thermoplastic resins, only thermoset resins or a combination of thermoplastic and thermoset resins. While these known composite bodies have various benefits, there is still room in the art for improvement. 
     SUMMARY OF THE DISCLOSURE 
     According to an aspect of the present disclosure, a component is provided that includes a multi-layer body configured with a thermoplastic layer, a thermoset layer and a scrim at an interface between the thermoplastic layer and the thermoset layer. The thermoplastic layer includes a plurality of reinforcement particles within a thermoplastic matrix. The thermoset layer is configured from or otherwise includes a thermoset matrix. 
     According to another aspect of the present disclosure, another component is provided that includes a multi-layer body configured with a thermoplastic layer, a thermoset layer and a scrim at an interface between the thermoplastic layer and the thermoset layer. The thermoplastic layer includes a plurality of thermoplastic particles within a thermoplastic matrix. A melting point of the thermoplastic matrix is less than a melting point of the plurality of thermoplastic particles. The thermoset layer includes fiber-reinforcement within a thermoset matrix. The scrim is configured from or otherwise includes fiber glass and/or carbon fiber. 
     According to still another aspect of the present disclosure, another component is provided for an aircraft. The component includes a skin and a thermoplastic structural support. The skin includes a thermoplastic layer, a thermoset layer and a scrim at an interface between the thermoplastic layer and the thermoset layer. The thermoplastic layer includes a plurality of particles within a thermoplastic matrix. The thermoset layer includes fiber-reinforcement within a thermoset matrix. The thermoset layer is configured to form an exterior flow surface of the component. The thermoplastic structural support is bonded to the thermoplastic layer. The thermoplastic structural support is configured to structurally reinforce the skin. 
     According to still another aspect of the present disclosure, a method is provided for forming a component. This method includes: providing a thermoplastic layer that includes a plurality of reinforcement particles within a thermoplastic matrix; providing a thermoset layer configured from or that otherwise includes a thermoset matrix; providing a scrim; and curing and consolidating the thermoplastic layer, the thermoset layer and the scrim together to form a multi-layer body. The multi-layer body is configured with the scrim at an interface between the thermoplastic layer and the thermoset layer. 
     The scrim may be embedded within the thermoplastic layer at the interface. 
     The scrim may be embedded within the thermoset layer at the interface. 
     The thermoplastic matrix may include polyvinylidene fluoride or nylon. The plurality of thermoplastic particles may include polyether ether ketone. 
     The component may include a thermoplastic structural support bonded to the thermoplastic layer. The multi-layer body may be configured as an exterior skin of the component that is supported by the thermoplastic structural support. 
     The thermoplastic matrix may be configured from or otherwise include polyvinylidene fluoride. 
     The thermoplastic matrix may be configured from or otherwise include nylon. 
     The plurality of reinforcement particles may be or otherwise include a plurality of thermoplastic particles. A melting point of the thermoplastic matrix may be less than a melting point of the plurality of thermoplastic particles. 
     The plurality of reinforcement particles may be or otherwise include a plurality of polyether ether ketone particles. 
     The thermoplastic layer may be about fifty percent by volume of the plurality of reinforcement particles and about fifty percent by volume of the thermoplastic matrix. 
     The plurality of reinforcement particles may be or may otherwise include a plurality of nano-particles. 
     The plurality of reinforcement particles may be or may otherwise include a plurality of micro-particles. 
     The thermoplastic layer may further include a plurality of carbon particles. 
     The thermoset layer may further include fiber-reinforcement material within the thermoset matrix. 
     The scrim may be configured from or otherwise include carbon fibers. 
     The scrim may be configured from or otherwise include glass fibers. 
     The scrim may be impregnated with the thermoplastic matrix. 
     The scrim may be impregnated with the thermoset matrix. 
     The thermoplastic matrix may be mixed with the thermoset matrix at the interface. 
     The component may also include a thermoplastic structural support bonded to the thermoplastic layer. The multi-layer body may include a skin that is supported by the thermoplastic structural support. The component may be configured as an aircraft component. 
     The foregoing features and the operation of the invention will become more apparent in light of the following description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective illustration of an aircraft, in accordance with various embodiments; 
         FIG. 2  is a sectional illustration of a thermoplastic-thermoset component, in accordance with various embodiments; 
         FIG. 2B  is an enlarged view of a portion of the thermoplastic-thermoset component of  FIG. 2 , in accordance with various embodiments; 
         FIG. 3  is a sectional illustration of another thermoplastic-thermoset component, in accordance with various embodiments; 
         FIG. 4  is a flow diagram of a method  400  for forming a component, in accordance with various embodiments; 
         FIG. 5  is a sectional illustration of a thermoplastic film, in accordance with various embodiments; 
         FIG. 6  is a sectional illustration of a scrim configured with the thermoplastic film, in accordance with various embodiments; 
         FIG. 7  is a sectional illustration of a scrim configured with an arrangement of fiber reinforcement, in accordance with various embodiments; 
         FIG. 8  is a sectional illustration of a multi-layer body included in the thermoplastic-thermoset component of  FIG. 2 , in accordance with various embodiments; and 
         FIG. 9  is a sectional illustration of a multi-layer body included in the thermoplastic-thermoset component of  FIG. 3 , in accordance with various embodiments. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a perspective illustration of an exemplary aircraft  10  configured as a passenger airliner. This aircraft  10  includes various exterior components  12 A-E (generally referred to as “ 12 ”) configured with aerodynamic exterior flow surfaces. Examples of such components  12  include, but are not limited to, a nacelle  12 A for an aircraft propulsion system  14  (e.g., a turbofan or turbojet engine system), a pylon  12 B, a fuselage  12 C and wings  12 D- 12 E. Such components  12  may each include an exterior skin that is reinforced/supported by one or more internal structural supports; e.g., ribs, stiffeners, longerons, pedestals, structural cores, etc. The exterior skin may form the aerodynamic exterior flow surface of the component  12 , which surface is directly exposed to air flowing along the component  12  during aircraft operation. 
       FIG. 2  a sectional illustration of a thermoplastic-thermoset component  16 . This thermoplastic-thermoset component  16  may be configured as one of the exterior components  12  described above with reference to  FIG. 1 . The thermoplastic-thermoset component  16 , however, is not limited to such exemplary exterior component configurations. The thermoplastic-thermoset component  16  is also not limited to exterior applications. For example, in other embodiments, the thermoplastic-thermoset component  16  may alternatively be configured as an interior component (e.g., a wall panel, a bifurcation panel, an inner fixed structure panel) of the aircraft  10 . The present disclosure is also not limited to the exemplary aircraft configuration of  FIG. 1 . For example, in other embodiments, the aircraft  10  may alternatively be configured as a business-jet, a cargo plane, a propeller plane, a helicopter or any other type of aircraft. Furthermore, the present disclosure is not limited to aircraft applications. For example, in other embodiments, the thermoplastic-thermoset component  16  may alternatively be configured as a structural or non-structural building panel. 
     The thermoplastic-thermoset component  16  of  FIG. 2  includes a multi-layer body  18  and one or more structural supports  20 . The multi-layer body  18  may be configured as a flat or contoured sheet of thermoplastic-thermoset material that extends laterally (e.g., axially and/or circumferentially) into and out of the plane of  FIG. 2 . The multi-layer body  18  has a thickness  22  that extends vertically (e.g., radially) within the plane of  FIG. 2  between a first surface  24  and an opposite second surface  26 . The first surface  24  may be an interior surface of the multi-layer body  18 . The second surface  26  may be an exterior surface (e.g., aerodynamic exterior flow surface) of the multi-layer body  18 . 
     The multi-layer body  18  of  FIG. 2  includes a thermoplastic layer  28 , a thermoset layer  30  and a scrim  32  arranged at (e.g., on, adjacent or proximate) an interface  34  between the thermoplastic layer  28  and the thermoset layer  30 ; see also  FIG. 2B . For example, as described below, the scrim  32  of  FIGS. 2 and 2B  is embedded into the thermoplastic layer  28  adjacent the interface  34  with heated roller for example. 
     The thermoplastic layer  28  forms the first surface  24 , and extends vertically from the first surface  24  to the interface  34  and, thus, the thermoset layer  30 . The thermoset layer  30  forms the second surface  26 , and extends vertically from the second surface  26  to the interface  34  and, thus, the thermoplastic layer  28 . A thickness  36  of the thermoplastic layer  28  may be different (e.g., less or alternatively more) than a thickness  38  of the thermoset layer  30 . For example, the thermoplastic layer thickness  36  may be less than or equal to exactly or about (+/−2%) twenty percent (20%) to one-hundred percent (100%) of the thermoset layer thickness  38 . In other embodiments, the thermoplastic layer thickness  36  may be greater than two-hundred percent (200%) or 2× of the thermoset layer thickness  38 . In still other embodiments, the thermoplastic layer thickness  36  may be greater than or exactly or substantially (+/−2%) equal to the thermoset layer thickness  38 . 
     The thermoplastic layer  28  may at least include (or may only include) a plurality of reinforcement particles  37  within a thermoplastic matrix; e.g., a thermoplastic resin. The thermoplastic matrix may at least include (or may only include) thermoplastic matrix material such as, but not limited to, semi crystalline and/or amorphous thermoplastics such as, for example, polyvinylidene fluoride (PVDF), nylon (e.g., nylon 6112), polyetherimide (PEI), polysulfone (PS) and/or polyethersulfone (PES). These thermoplastics have similar solubility parameters and/or melt temperatures conducive to co-curing with thermosets. 
     The reinforcement particles  37  may be configured as uniform or non-uniform nano-particles (also known as nanoscale particle) and/or micro-particles (also known as microscale particles). The term “nano-particle” may describe a particle with a maximum and/or minimum size (e.g., diameter) between one and one-hundred nanometers (nm). The term “micro-particle” may describe a particle with a maximum and/or minimum size (e.g., diameter) between one-tenth and one-hundred micrometers (μm). 
     Each reinforcement particles  37  may at least include (or may only include) thermoplastic particle material such as a high-temperature thermoplastic material. Such thermoplastic particle material may have a melting point that is greater than a melting point of the thermoplastic matrix material. For example, the melting point of the thermoplastic particle material may be greater than or equal to exactly or about (+/−0.5 degrees) 50 degrees Celsius more than of the melting point of the thermoplastic matrix material. With such a melting point differential, the reinforcement particles  37  may be disposed and remain in solid form within a liquid (e.g., melted) form of the thermoplastic matrix during the formation of the multi-layer body  18  as described below in further detail. 
     An example of the thermoplastic particle material is polyether ether ketone (PEEK). Other examples of the thermoplastic particle material include, but are not limited to, polyether ketone ketone (PEKK), polyphenylene sulfone (PPS) and polyaryletherketone (PAEK). 
     The thermoplastic layer  28  may include exactly or about (+/−2%) fifty percent by volume of the reinforcement particles  37 . The thermoplastic layer  28  may also include exactly or about (+/−2%) fifty percent by volume of the thermoplastic matrix. Of course, in other embodiments, the thermoplastic layer  28  may include more or less than fifty percent by volume of the reinforcement particles  37 . In addition or alternatively, the thermoplastic layer  28  may include less or more than fifty percent by volume of the thermoplastic matrix. Furthermore, in some embodiments, the thermoplastic layer  28  may include one or more additional additives/material/reinforcements. For example, the thermoplastic layer  28  may also include a plurality of carbon particles (e.g., carbon nanofibers) to provide additional layer reinforcement. Examples of exemplary carbon particles are disclosed in U.S. Pat. No. 9,511,562, which is hereby incorporated herein by reference in its entirety. 
     The thermoplastic layer  28  may at least include (or may only include) fiber-reinforcement within a thermoset matrix. The thermoset matrix may at least include (or may only include) thermoset matrix material such as, but not limited to, epoxies, bismaleimides (BMI) and benzoxazine. The fiber-reinforcement may at least include (or may only include) reinforcement fibers arranged in, for example, one or more two-dimensional (e.g., woven or non-woven) sheets and/or three-dimensional (e.g., woven) bodies. Examples of the reinforcement fibers include, but are not limited to, fiber glass fibers, carbon fibers and aramid fibers (e.g., Kevlar®), or some combination thereof. 
     The scrim  32  may be configured as a relatively thin porous sheet of fiber material; e.g., a fiber veil. This scrim  32  may at least include (or only include) woven or non-woven carbon fibers, fiber glass fibers, aramid fibers or some combination of such fibers. The areal weight of the scrim  32  may be exactly or about (+/−2%) fifty percent (50%) or less than the reinforcement areal weight in the thermoset layer  30 . In the embodiment of  FIG. 2 , the scrim  32  is located just adjacent (e.g., bordering and touching) the interface  34  between the thermoplastic layer  28  and the thermoset layer  30 , and is included (e.g., embedded) in the thermoplastic layer  28 . However, in other embodiments, the scrim  32  may be located just adjacent the interface  34  between the thermoplastic layer  28  and the thermoset layer  30 , and included (e.g., embedded) in the thermoset layer  30  as shown in  FIG. 3 , for example. 
     Referring again to  FIG. 2 , at the interface  34 , the thermoplastic matrix material interacts (e.g., mixes and interlocks) with the thermoset matrix material. This interaction mechanically entangles and interlocks the thermoplastic layer  28  and the thermoset layer  30  together and with functionalized particles and scrim chemically bonds the layers together. A tie layer may thereby be provided using the scrim  32  at the interface  34  that improves fluid resistance and joining structural properties that can be a problem with the prior disclosed art. The tie layer, for example, may have susceptibility to chemical fluid resistance, and lower melt temperature semi-crystalline thermoplastics may have lower mechanical properties at high temperature. 
     Each structural support  20  of  FIG. 2  may be configured as a (e.g., laterally extending) rib; e.g., a T-beam, an I-beam, a C-channel, etc. However, in other embodiments, one or more of the structural supports  20  may each be configured as another type of support such as, but not limited to, a stiffener, a longeron, a pedestal, a structural (e.g., honeycomb) core, etc. Each structural support is welded, adhered and/or otherwise bonded to the thermoplastic layer  28 . For example, a base  42  of each structural support  20  in  FIG. 2  is abutted against the first surface  24  of the multi-layer body  18 , and bonded to the thermoplastic layer  28  or it may be a hybrid thermoset/thermoplastic. The hybrid thermoset/thermoplastic may be a structure including a thermoplastic overmolded onto a cured thermoset or thermoplastic film that is co-cured with the thermoset. 
     Each structural support  20  may be a thermoplastic structural support. For example, each structural support  20  may be formed from the same material as the thermoplastic layer  28 . Alternatively, one or more of the structural supports  20  may each be formed from thermoplastic material that is different from the material of the thermoplastic layer  28 . 
       FIG. 4  is a flow diagram of a method  400  for forming a component such as the thermoplastic-thermoset component  16  of  FIGS. 2 and 3 . In step  402 , a thermoplastic film  44  is provided as shown, for example, in  FIG. 5 . This thermoplastic film  44  may include one or more or all of the components in the thermoplastic layer  28 . For example, the thermoplastic film  44  may include the reinforcement particles  37  as well as the carbon particles and/or other additional additives/material/reinforcements. As the film is being formed, the thermoplastic matrix may be melted into a liquid form. The other particles, which are in solid form, may then be added and mixed (e.g., shear mixed) into the melted thermoplastic matrix. This mixture may then be cooled to provide the thermoplastic film  44 . 
     In step  404 , an arrangement  46  of the fiber reinforcement for the thermoset layer  30  is provided. This arrangement  46  of the fiber reinforcement may include one or more stacked sheets of the fiber reinforcement, which may be pre-impregnated with the thermoset matrix. Thus, the arrangement  46  of the fiber reinforcement may include one or more stacked sheets of prepreg material, which include the fiber reinforcement and the thermoset matrix. 
     In step  406 , the scrim  32  is arranged with either the thermoplastic film  44  (see  FIGS. 2, 6 and 8 ) or the arrangement  46  of the fiber reinforcement for the thermoset layer  30  (see  FIGS. 3, 7 and 9 ). For example, the scrim  32  may be tacked onto an interior surface  48  of the thermoplastic film  44  as shown in  FIG. 6 . In another example, the scrim  32  may be at least partially impregnated with the thermoplastic matrix and laid against and thereby bonded to the interior surface  48 . In still another example, the scrim  32  may be similarly tacked or otherwise bonded onto an interior surface  50  of the arrangement  46  of the fiber reinforcement as shown in  FIG. 7 . 
     In step  408 , the material is laid up in a stack with the scrim  32  between the thermoplastic film  44  and the arrangement  46  of the fiber reinforcement. In step  410 , the stack of material is cured and consolidated together, for example, in an autoclave or with out of the autoclave (OOA) processing to provide a multi-layered body as shown in  FIGS. 8 and 9 . During this curing, the thermoplastic matrix and the thermoset matrix liquefy/melt. The melted thermoplastic material is thereby operable to migrate through pores of the scrim  32  and interface with the liquid thermoset material. The scrim  32 , however, may serve to substantially or completely prevent migration of the reinforcement particles  37  out of the thermoplastic layer  28 . Thus, the reinforcement particles  37  within the thermoplastic matrix of the thermoplastic film  44  substantially remain within the formed thermoplastic layer  28 ; e.g., above the scrim  32  in the figures. Some of the additional particles (e.g., the carbon particles), however, may migrate through the scrim  32  and strengthen the bonded interface between the thermoplastic layer  28  and the thermoset layer  30  as illustrated in  FIG. 2B . However, a density of the particles  37  above the scrim  32  of  FIG. 2B  may significantly (e.g., 5-10×) greater than a density of the particles  37  below the scrim  32 . 
     In step  412 , the one or more structural supports  20  are bonded to the thermoplastic layer  28  to provide components as illustrated in  FIGS. 2 and 3 , for example. 
     While various embodiments of the present invention have been disclosed, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the invention. For example, the present invention as described herein includes several aspects and embodiments that include particular features. Although these features may be described individually, it is within the scope of the present invention that some or all of these features may be combined with any one of the aspects and remain within the scope of the invention. Accordingly, the present invention is not to be restricted except in light of the attached claims and their equivalents.