Joint between different thermoplastic materials

Abstract

A dissimilar thermoplastic joint (10) comprising a first thermoplastic layer (12), a second thermoplastic layer (14) having a melting point temperature (B) different from a melting point temperature (A) of the first thermoplastic layer (12), and an interface layer (16) bonded between the first thermoplastic layer (12) and the second thermoplastic layer (14), the interface layer (16) being configured to bond the first thermoplastic layer (12) and the second thermoplastic layer (14) together to form the joint (10), the interface layer (16) comprising a melting point temperature having a value selected from the group consisting of between the melting point temperature (A) of the first thermoplastic layer (12) and the melting point temperature (B) of the second thermoplastic layer (14) or lower than the melting point temperature (A) of the first thermoplastic layer (12) and the melting point temperature (B) of the second thermoplastic layer (14).

Description

Background Art

[0001] The present disclosure is directed to an interface configured to join two different thermoplastic materials during welding.

[0002] Thermoplastic composites are emerging as alternatives to thermoset composites in various applications due to their rapid processing, weldability, high impact resistance, and potential for low cost. Joining dissimilar thermoplastic materials and / or their composites remains difficult, especially when the thermoplastic materials involved have very different processing temperatures.

[0003] One previous solution has been bonding with adhesives. To bond a thermoplastic such as polycarbonate (PC) to polyetheretherketone (PEEK), many process steps are required, such as surface treatment agents, application of adhesives, and heat curing in an autoclave or oven (all of which are required). The overall process is very time-consuming and costly. Another potential option for joining dissimilar thermoplastic materials is mechanical fastening. However, mechanical fastening includes weight disadvantages and does not meet many of the sealing requirements of the joints required.

[0004] What is needed is a material interface that enables welding of two different thermoplastic materials / composites.

Summary of the Invention

[0005] According to the present disclosure, there is provided a joint between dissimilar thermoplastic materials including a first thermoplastic material layer, a second thermoplastic material layer having a melting point temperature different from that of the first thermoplastic material layer, and an interface layer bonded between the first thermoplastic material layer and the second thermoplastic material layer. The interface layer is configured to bond both the first thermoplastic material layer and the second thermoplastic material layer to form the joint. The interface layer includes a melting point temperature selected from the group consisting of between the melting point temperature of the first thermoplastic material layer and the melting point temperature of the second thermoplastic material layer, or lower than the melting point temperature of the first thermoplastic material layer and the melting point temperature of the second thermoplastic material layer.

[0006] Any further embodiment of any of the above embodiments may further and / or alternatively include at least one of the first thermoplastic material layer and the second thermoplastic material layer including a thermoplastic composite material.

[0007] Any further embodiment of any of the above embodiments may further and / or alternatively include a surface treatment agent for at least one of the first thermoplastic material and the second thermoplastic material layer, and includes a joint between dissimilar thermoplastic materials.

[0008] Any further embodiment of any of the above embodiments may further and / or alternatively include the first thermoplastic material layer and the second thermoplastic material layer which may include at least one of polycarbonate, polyetherimide, polyphenylene sulfide, polyether ketone ketone, polyaryl ether ketone, and polyether ether ketone.

[0009] According to the present disclosure, an attachment welded to a component via an interface layer, the attachment including a first thermoplastic material, a component including a second thermoplastic material having a melting point temperature different from the melting point temperature of the first thermoplastic material, and an interface layer bonded between the attachment and the component are provided. The interface layer is configured to join both the first thermoplastic material and the second thermoplastic material to form a welded joint. The interface layer includes a melting point temperature selected from the group consisting of between the melting point temperature of the first thermoplastic material layer and the melting point temperature of the second thermoplastic material layer, or lower than the melting point temperature of the first thermoplastic material layer and the melting point temperature of the second thermoplastic material layer.

[0010] Any further embodiment of any of the above embodiments may further and / or alternatively include at least one of the first thermoplastic material and the second thermoplastic material including a thermoplastic composite material.

[0011] Any further embodiment of any of the above embodiments may further and / or alternatively include a surface treatment agent for at least one of the attachment and the component.

[0012] Any further embodiment of any of the above embodiments may further and / or alternatively include a fiber reinforcement on the interface layer.

[0013] According to the present disclosure, a process for welding an attachment to a component with an interface layer is provided, including providing an attachment including a first thermoplastic material, providing a component including a second thermoplastic material having a melting point temperature different from the melting point temperature of the first thermoplastic material, and welding an interface layer between the attachment and the component. The interface layer is configured to join both the first thermoplastic material and the second thermoplastic material to form a weld. The interface layer includes a melting point temperature selected from the group consisting of between the melting point temperature of the first thermoplastic material layer and the melting point temperature of the second thermoplastic material layer, or lower than the melting point temperature of the first thermoplastic material layer and the melting point temperature of the second thermoplastic material layer.

[0014] A further embodiment of any of the above embodiments may further include a process that further and / or alternatively performs a surface treatment on at least one of the attachment and the component.

[0015] A further embodiment of any of the above embodiments may further include a process that further and / or alternatively applies a fiber reinforcement to the interface layer.

[0016] A further embodiment of any of the above embodiments may further include a process that further and / or alternatively incorporates an interface layer into at least one of the attachment and the component.

[0017] A further embodiment of any of the above embodiments may further include a process that further and / or alternatively forms an interface layer over at least one of the attachment and the component.

[0018] A further embodiment of any of the above embodiments may further include a process that further and / or alternatively coats an interface layer on at least one of the attachment and the component.

[0019] A further embodiment of any of the above embodiments may further and / or alternatively include an interface layer that includes a material having a lower processing temperature that chemically interacts with and bonds the first thermoplastic material and the second thermoplastic material when no melting is present during welding.

[0020] Other details of the interface material are described in the following mode for carrying out the invention and the accompanying drawings in which like reference numerals indicate like components. BRIEF DESCRIPTION OF THE DRAWINGS

[0021]

Figure 1

Figure 2

Figure 3

[0022] Referring to FIGS. 1 and 2, an exemplary joint 10 between a first thermoplastic material layer 12, a second thermoplastic material layer 14, and an interface layer 16 is shown. The first thermoplastic material layer 12 may include one of a single thermoplastic substance and a composite thermoplastic material, as shown in FIG. 2. The second thermoplastic material layer 14 may include one of a single thermoplastic substance and a composite thermoplastic material. The interface layer 16 is located between the first thermoplastic material layer 12 and the second thermoplastic material layer 14. The interface layer 16 is configured to join both the first thermoplastic material layer 12 and the second thermoplastic material layer 14 to form the joint 10. In an exemplary embodiment, the thermoplastic material may be at least one of polycarbonate (PC), polyetherimide (PEI), polyphenylene sulfide (PPS), polyether ketone ketone (PEKK), polyaryl ether ketone (PAEK), polyether ether ketone (PEEK), etc.

[0023] The first thermoplastic material layer 12 may have a first melting point temperature A. The second thermoplastic material layer 14 may have a second melting point temperature B. In an exemplary embodiment, the first melting point temperature A is different from the second melting point temperature B. The interface layer 16 may have a melting point temperature C that is between the first melting point temperature A and the second melting point temperature B. In an exemplary embodiment, the interface layer 16 may include a melting point temperature D that is lower than both the melting point temperatures of the first thermoplastic material layer 12 and the second thermoplastic material layer 14.

[0024] Also, referring to FIG. 3, as shown, a component 18 containing a thermoplastic material X is attached to an attachment 20 containing a thermoplastic material Y with an interface layer 22 bonded therebetween. The component 18 may also include a thermoplastic composite material 24. As in the exemplary embodiments shown in FIGS. 1 and 2, the interface layer 22 may include a melting point temperature C having a value between the melting point temperature A of the attachment 20 and the melting point temperature B of the component 18.

[0025] Referring to FIGS. 1 and 2, in an exemplary embodiment, the interface layer 16 may be molded onto the first thermoplastic material layer 12 and / or may be molded onto the second thermoplastic material layer 14. In an exemplary embodiment, the interface layer 16 may be coated onto the first thermoplastic material layer 12 and / or may be coated onto the second thermoplastic material layer 14.

[0026] Referring to FIG. 3, in an exemplary embodiment, in order to improve adhesion, a surface treatment agent 26 can be applied to the component 18 and / or the attachment 20 proximate to the interface layer 22. The surface treatment agent 26 may include a surface abrasive, a plasma treatment agent, a laser ablation treatment, a flame treatment, sanding, grit blasting, a chemical treatment, a surface polish + solvent wiping, etc.

[0027] Example 1. The injection-molded polycarbonate (PC) attachment is welded to a carbon fiber-reinforced polyether ether ketone (CF / PEEK) composite tube component. The amorphous PC has a glass transition temperature of about 155 degrees Celsius (°C) and a molding temperature of about 280 °C, while the semi-crystalline PEEK melts at about 343 °C and can be molded at about 390 °C. As a result, a temperature difference (>100 °C) occurs between the materials to be joined. Welding the two materials directly together causes two problems. First, at low temperatures, PEEK does not melt. Therefore, molecular chain diffusion at the joint interface cannot be achieved. Second, instead, the welding temperature becomes high enough to melt the PEEK component, but at the same time, due to the adhesion of the PC, its shape is lost or even thermal degradation occurs.

[0028] An exemplary solution to the problem involves using an interfacial layer / surface material that joins the two different thermoplastics together during welding. A material with a wide processing temperature range can be utilized for the interfacial layer and / or the interfacial layer may have a lower processing temperature material that chemically interacts with and bonds well to the two thermoplastics that do not melt during welding. An exemplary interfacial layer material may be thermoplastic polyurethane (TPU). TPU melts at about 180 °C. The TPU material can function as an interfacial layer for welding PC and PEEK.

[0029] The interfacial layer can first be integrated with the high-temperature thermoplastic and then welded to the lower processing temperature thermoplastic, such as PC. Another exemplary interfacial layer is polyetherimide (PEI). PEI has a processing temperature range of 335 °C to 420 °C and a softening point temperature of 217 °C. PEI is compatible with both PC and PEEK and can function as an interfacial layer material for welding PC to PEEK.

[0030] More specifically, the interface layer can be utilized before welding the attachment to the component. One embodiment of utilizing the interface layer before welding the attachment to the component may include coating or molding a low-temperature interface layer material, such as a thermoplastic urethane layer (TPU), on either the surface of the PC attachment and / or the CF / PEEK component. Another embodiment of utilizing the interface layer before welding the attachment to the component may include molding a higher-temperature interface layer material, such as a polyetherimide (PEI), on the surface of the CF / PEEK component. PEI is expected to integrate better with PEEK. In welding, PEI also welds (with molecular chain diffusion) to the PC material. Also, a lower welding temperature (much lower than the PEEK processing temperature) presents fewer issues in maintaining the shape and performance of the CF / PEEK component and the PC attachment.

[0031] In an exemplary embodiment, welding an attachment to a component having an interface layer therebetween may include alternative rapid welding methods. Such welding methods may include resistance welding, induction welding, ultrasonic welding, or laser welding. In an exemplary embodiment, a reinforcing material 28, such as a fiber reinforcement 28, can be utilized in the interface layer material 22 and is preferred when resistance welding is used. The fiber reinforcement 28 for the interface layer 22 may be one of carbon fiber, glass fiber, Spectra® , Kevlar® , etc., which are utilized when induction welding is used. Laser welding can be an option when one of the thermoplastic layers 12, 14 is transparent.

[0032] The technical advantages of the disclosed interface material joint include an interface / surface layer for facilitating the welding of dissimilar thermoplastics and / or their composite materials.

[0033] The technical advantages of the disclosed interface material joint include maintaining the integrity, shape, and performance of the component substrate being welded.

[0034] The technical advantages of the disclosed interface material joints include providing a seal between the composite materials being joined.

[0035] The technical advantages of the disclosed interface material joints include providing surface protection to the composite materials being joined.

[0036] The technical advantages of the disclosed interface material joints include reducing processing assembly time and cost.

[0037] An interface material is provided. The interface material is described in the context of its particular embodiments, but other unexpected alternatives, variations, and modifications may become apparent to those skilled in the art upon reading the above description. Accordingly, it is intended to embrace alternatives, variations, and modifications that fall within the broad scope of the appended claims.

Claims

1. A joint between dissimilar thermoplastic materials, a first thermoplastic material layer, a second thermoplastic material layer having a melting point temperature different from that of the first thermoplastic material layer, an interface layer bonded between the first thermoplastic material layer and the second thermoplastic material layer, configured to join the first thermoplastic material layer and the second thermoplastic material layer to form the joint, and having, the first thermoplastic material layer is larger in size than the second thermoplastic material layer, the interface layer includes a melting point temperature selected from the group consisting of between the melting point temperature of the first thermoplastic material layer and the melting point temperature of the second thermoplastic material layer, or a temperature lower than the melting point temperature of the first thermoplastic material layer and the melting point temperature of the second thermoplastic material layer, the interface layer has polyetherimide, the interface layer includes glass fibers as a reinforcing material, a joint between dissimilar thermoplastic materials.

2. The joint between dissimilar thermoplastic materials according to claim 1, wherein at least one of the first thermoplastic material layer and the second thermoplastic material layer includes a thermoplastic composite material.

3. Furthermore, on at least one of the first thermoplastic material layer and the second thermoplastic material layer, the joint between dissimilar thermoplastic materials according to claim 1, including a surface treatment.

4. The joint between dissimilar thermoplastic materials according to claim 1, wherein the first thermoplastic material layer and the second thermoplastic material layer may include at least one of polycarbonate, polyphenylene sulfide, polyether ketone ketone, polyaryl ether ketone, and polyether ether ketone.

5. The joint between dissimilar thermoplastic materials according to claim 1, wherein the interface layer includes a material that chemically interacts with and bonds to the non-molten first thermoplastic material layer and the second thermoplastic material layer.

6. An attachment welded to a component via an interface layer, the attachment including a first thermoplastic material, the component including a second thermoplastic material having a melting point temperature different from that of the first thermoplastic material, an interface layer bonded between the attachment and the component, configured to join the first thermoplastic material and the second thermoplastic material to form a welded joint, and having, The component is larger in size than the attachment, The interface layer includes a melting point temperature selected from the group consisting of a temperature between the melting point temperature of the first thermoplastic material and the melting point temperature of the second thermoplastic material, or a temperature lower than the melting point temperature of the first thermoplastic material and the melting point temperature of the second thermoplastic material, The interface layer has polyetherimide, The interface layer includes glass fibers as a reinforcing material, and an attachment welded to the component through the interface layer.

7. The attachment welded to the component through the interface layer according to claim 6, wherein at least one of the first thermoplastic material and the second thermoplastic material includes a thermoplastic composite material.

8. Furthermore, an attachment welded to the component through the interface layer according to claim 6, including a surface treatment on at least one of the attachment and the component.

9. A process of welding an attachment to a component using an interface layer, Providing the attachment including a first thermoplastic material; Providing the component including a second thermoplastic material having a melting point temperature different from the melting point temperature of the first thermoplastic material; Welding an interface layer between the attachment and the component, the interface layer being configured to join the first thermoplastic material and the second thermoplastic material to form a welded portion; having, The interface layer includes a melting point temperature selected from the group consisting of a temperature between the melting point temperature of the first thermoplastic material and the melting point temperature of the second thermoplastic material, or a temperature lower than the melting point temperature of the first thermoplastic material and the melting point temperature of the second thermoplastic material, The component is larger in size than the attachment, The interface layer has polyetherimide, The interface layer includes glass fibers as a reinforcing material, the process.

10. The process according to claim 9, further comprising performing a surface treatment on at least one of the attachment and the component.

11. The process according to claim 9, further comprising incorporating the interface layer into at least one of the attachment and the component.

12. The process of claim 9, further comprising the step of forming the interface layer on at least one of the attachment and the component. **Claim 13** The process of claim 9, further comprising the step of coating the interface layer on at least one of the attachment and the component. **Claim 14** The interface layer comprises a material having a lower processing temperature, which chemically interacts with and bonds to the first thermoplastic material and the second thermoplastic material when there is no melting during the welding. The process according to claim 9.

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