Patent Application
20140158297
Self-reinforced thermoplastic composites have found utility in a variety of fields. Much of the previous innovation has focused on performance attributes, including the ability to shape, reshape and join the composite pieces. Some attention has been given to the material in terms of its potential for recycling and closed-loop “cradle-to-cradle” product cycles or systems.
The assignee hereof (Smarter Planet, LLC) is in the business of implementing such product solutions as its members successfully demonstrated on the Plastiki project. The Plastiki boat was built using a srPET (self-reinforced polyester) composite frame securing 12,000 two-liter bottles for buoyancy. These elements, together with the boat cabin, furniture, rudder and other structural features we built from srPET. Thus, if ever stripped of its rigging, the Plastiki can be fully recycled. It can be inserted into the PET recycling stream and fully utilized in any number of newly-minted consumer goods.
The building of the Plastiki and its voyage across the Pacific Ocean are well publicized. The vessel embodies a vision of recycled/recyclable product use. Through this vision, the public learned key messages of conservation.
Unexpected, however, was the public's keen interest in the underlying srPET technology upon which the craft was built. Government representatives, academic leaders, corporate chiefs and others voiced immediate interest in high-value structural goods produced for and from this recycled “high-tech” material. That interest represents a need which has not been met by others working in the thermoplastic composites field.
In producing such goods, it is often necessary or desirable to weld together various component parts. In the context of the present inventions, features are contemplated to assist in heat bonding elements together. Various design for assembly features are disclosed for improving and/or enabling the subject constructs.
The various embodiments described herein are advantageously constructed with thermoplastic composite material. These possibilities are especially beneficial in an ecological sense when implemented with easily recyclable materials. Accordingly, use of srPET composite material is a focus. In this material, high melt (high tenacity fiber component) and lower melt (matrix material component) portions of the srPET material are chemically compatible such that structures can be ground/chipped-up at the end of their useful life and incorporated directly into the existing PET waste stream that now largely constitutes spent two-liter bottles and other beverage containers. However, it is to be understood that the teachings herein are generally applicable to other thermoplastic composite materials such as produced by Comfil, Inc. and/or others. In any case, several such examples are provided in the table below:
Other suitable materials to form layers of composite material utilized in the present inventions are described in any of U.S. Pat. Nos. 3,765,998; 4,414,266; 4238,266; 4,240,857; 5,401,154; 6,828,016; 6,866,738 and US Publication Nos. 2001/0030017 and 2011/0076441 among others.
As for the inventive variations, they include a number of thermoplastic construction “tools” suitable for producing high-value self-reinforced composite structural goods (recreational and otherwise). These may be paired/utilized in connection with known techniques for handling such material. Examples of such techniques defining the state of the art (e.g., for molding, stamping, heating, cooling, etc.) are included in the referenced patents, each patent incorporated by reference herein in its entirely.
The “tools” covered in the subject disclosure are all directed toward producing precursor assemblies or preform constructions that are heated globally or locally to cause thermoplastic material therein to flow and bond the assembly into a unitary (even seamless) structure. These advances comprise a group of weld-facilitating designs selected from: I) Structures with Weld-Enhancing Contours; II) Weld-Ready Flow Features and Coordinated Structures for Welded Assembly; and III) Multi-Modal Composite Preforms for Welded Constructs. Each one describes an approach to providing complementary-shaped elements for the welding process. Often, these are “related” as in a male-female or convex-concave relationship, twinned structure, jig-sawed, complementary function (e.g., hook and loop, etc.) or as otherwise shown and/or described. The present inventions also include the subject products, kits (for production, distribution, sale or otherwise) in which they are included and methods of manufacture and use. More detailed discussion is presented in connection with the figures below.
The figures provided herein may be diagrammatic and are not necessarily drawn to scale, with some components and features exaggerated for clarity. Each of the figures diagrammatically illustrates aspects of the inventions. Of these:
Variations of the inventions from the examples pictured are contemplated. Accordingly, depiction of aspects and elements of the inventions in the figures are not intended to limit the scope of the invention. However, the figures themselves and included text incorporates features that may be set forth otherwise in the specification may serve as the basis for claim limitations—as originally presented or as introduced by amendment.
As per above, the present inventions includes constructional techniques as well as finished goods produced thereby. The techniques can be regarded as new “tools” that can be applied broadly across the composites fields, especially within the self-reinforced composite field. As such, various exemplary embodiments are described below. Reference is made to these examples in a non-limiting sense. They are provided to illustrate more broadly applicable aspects of the present inventions. Various changes may be made to the inventions described and equivalents may be substituted without departing from the true spirit and scope of the inventions. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process act(s) or step(s) to the objective(s), spirit or scope of the present inventions. All such modifications are intended to be within the scope of the claims made herein.
Structures with Weld-Enhancing Contours
In this aspect, provision is made for welding structures together in a final, flat apposition. As illustrated in
Notably, US Patent Application Publication 2005/0082881 shows bonding thermoplastic sheets in which a convex surface is bonded to a flat surface. In contrast, however, the convex surface is maintained, rather than pressed flat (or at least substantially so).
As per
Stated otherwise, the heat applied to the area between the convex sides first allows thermoforming of the mating surfaces followed by welding. By achieving a weld bead that travels away from the point where both convex surfaces meet, the elimination of air voids in the finished part is greatly simplified. In doing so, the mold shape may assists in attaining accurate shape and provide a framework to achieve transitional geometry (round to hex) or help assume shapes such as handle grips, textures or locating points for hardware. In one implementation, two halves a ribbed structural beam are provided.
According to this approach, finished tubular product supported with one or more cross members are provided. A similar approach is also achievable using folded or pleated preforms to form a pie shape with multiple supporting members within the cross section of a tubular shape.
The heating applied to facilitate bonding may be inductive in nature (e.g., if the material to be bonded is associated with or doped with ferromagnetic material). In another approach, hot air is blown through the tubular segments (possibly directed by an air curtain). In another approach, hot air blows (as illustrated in
Of course, the bonding approach is applicable to other structures as well. It may be applied in bonding layered slices, panels and other structures—especially in situations where vacuum (as in a bag or tooling) is not readily applied and trapped air between layers is best avoided. As such, it may be advantageously applied in modular home/barrack/shelter, blast or ballistic curtains/walls, water craft (especially boat) and other construction.
U.S. Pat. No. 7,235,145 shows raised polymer matrix features associated with a thermoplastic composite body to assist in welding it to another body upon application of energy. A structurally similar approach was employed welding hardware covers on the Plastiki hull. The bumps/elevated features provided reservoirs of matrix material ready to flow and bond the parts when heated. It is heretofore unknown, however, to provide interfacing sets of such features. By providing specifically coordinated features, positional location for welding/bonding can be assisted or ensured.
In
In addition to the ribs helping mate the composite parts, they provide a “metered” volume of thermoplastic adhesive which is critical to maintain proper fiber/matrix ratios throughout bondline features where the backing comprise thermoplastic composite material. A friction fit or snapping effect may be utilized to hold tapes or panels straight before incorporating heat and pressure from a wide variety of thermoplastic welding/bonding techniques and equipment. Moreover, the complementary bead/rib features may incorporate a core material acting as a bondline thickness/pressure control element. Still further, it is to be appreciated, that the ribs, these may friction fit or snap together—complementary elements may comprise oppositely facing interlocking grids. Indeed the shape of the additional matrix for bonding may be even be shaped like LEGO pieces to mate one sheet with another.
In
In another variation, the interfacing features can be coordinated to mesh or connect in only in one given overlap/overlay pattern for fail-safe assembly positioning. Such a system is illustrated in
Such features may be designed to provide a vertical mechanical interlock between pieces in preparation and for the further benefit of welding. Regardless if complementary positioning features are provided, another type of unique complementary weld-ready interface is shown in connection with backings 80, 80′ in
Any of the backing-applied features may be of such type that melt and bond and lose their discrete identity/form upon heating. Use of such features may help to stabilize parts for bonding. They may also increase bond strength, especially when at least some of the members incorporated high-tenacity/melt fiber or are otherwise reinforced.
In yet another approach, elevated features are provided upon at least one of two members to bond. However, instead of seeking to fill complementary space as in either approach above, the gaps are filled with a structural foam or another material with higher melt temperature than the bonding matrix (e.g., higher molecular weight PET—such as used in comingled srPET fabric—in the form of beads, pucks, pellets, straws, single honeycomb cells or another configuration or LWRT as described by the applicant hereof as called out and incorporated by reference below). When foam is used, the remainder of the foam planed off. The resulting structure then includes locally cored regions. The diameter (length and/or width) of these coring structures can easily be set at the mm or sub-millimeter scale. When welding a body so-prepared to another, the high melt temp filler maintains a desirable gap or distance between the parts. It can also prevent unwanted outflow of matrix material when compressing the parts together. Moreover, when complementarily cored pieces are employed, a unique moderate-density structure is produced with coring and matrix bridging elements. Such an implementation can be visualized in connection with
In another implementation, raised features form channels or micro-channels for flowing a welding solvent between opposed material. Again,
Note that any of the above bump/raised features may be formed by heating thermoplastic composite fabric so its matrix material flows in communication with a textured backing (e.g., molded silicone) or by employing a heated stamper or roller. Another approach is to machine (mechanically, by laser, water-jet or otherwise) the features in a bonded composite layer or a contact (film) layer to bond to a composite panel layer. Other printing or deposition approaches may be employed as well, including hot-melt, silk screening and other approaches. Any of these enable precise metering of the matrix material intended for bonding, processing high volume at low cost. Using this inexpensive high volume processes permits precise metering of thermoplastic adhesives to be accurately metered onto a surface in a precise shape. The dots, squares, or specified shapes need only to be melted with pressure and time enough to allow the shapes to engage each other. Most all thermoplastic adhesives have very high melt viscosity requiring high pressures and long dwell times to squeeze excess adhesive out the edges of a laminate. The patterns can also be designed to channel out air during the weld similar to the action of tire treads.
U.S. Pat. Nos. 5,418,035; 5,464,493 and 6,162,314 offer a useful tool. However, their purpose and implementation is limited. The patents merely contemplate tacking multiple layers of composite together for manipulation in bulk. Moreover, none recognize the benefit of (aspects of the '035 and '493 actually teach away from) creating performs with one or more hinging sections connecting adjacent less flexible (i.e., semi-bonded or unbonded phase fabric) composite sections.
In these aspects of the present inventions, selective bonding of a preform for producing a final product is usefully implemented even with a single layer of thermoplastic composite material fabric (vs. stacked material). In certain embodiments, it is most advantageously so-implemented. Regarding discussion of the various phases to which thermoplastic composite material may be consolidated, reference is made to PCT application entitled, “Hybrid Thermoplastic Composite Goods,” filed on even date herewith and incorporated by reference in its entirety.
In reference to the lacrosse handle embodiment (a lacrosse handle 90 illustrated in cross section in
With the flexible sections defining hinge lines/sections, precision placement can be achieved with more rigid sections (e.g., sections A-H) seating/lying against complementary mandrel/mold sections. The flexible sections, then, operate as hinges for layup (e.g., over a complex surface) or wrapping (e.g., over one or more mandrels).
When involving selectively laminated layers of material, unbonded flexible sections of material can define pockets to receive other material. For example, Nitinol ribs or spars/stringers (not shown) may be slipped in between layers along the hinges and precisely aligned in this fashion. Otherwise, additional composite material tow lines (preferably comingled thermoplastic composite such as used for the fabric layers itself) can be passed between the layers (not shown).
As another option, the more flexible sections can define paths for stitching/sewing the layers together. The stitching can help prevent delaminating in the final composite product against impact damage in the finally-bonded product. Especially when the flexible sections are used as hinge elements in wrapping a preform around a mandrel to define a handle with edges subject to impact (as in a lacrosse or hockey stick), the sewing may be especially useful. High strength filament/thread may be used for the sewing such as SPECTRA, VECTRAN or DYNEMA for such purposes.
Another option is to modify the more rigid/bonded sections. Particularly, they may be cut-out (e.g., using a punch press, CNC mill or drag knife). The resulting cutouts 106 then can play a role in defining a lighter weight and higher performance structure.
In one example, cutouts are placed along the internal surface of the structure. This can lighten the wall of a structure while maintaining full thickness along its edges/corners. This may be advantageous when the primary failure conditions is impact/impulse loading at the corners. The cutouts 106 may also (or alternatively) serve as location features with coordinated protrusions 94 on opposing molding body (i.e., the mandrel, a mold cavity, etc.).
In another example, cutouts 106′ are trapped between overlaying “skin” layers. These may be left vacant or filled with inserts 96 made of foam, honeycomb, LWRT, etc. Such an approach may be especially advantageous from the perspective of reducing overall weight while maintaining optimal beam strength. Of course, hybrid constructions can be provided in which both of these tools are employed.
Open or closed-off, the cutout pattern can be designed to deliver desired properties. Especially when the composite structural fibers are aligned with the struts of a cutout pattern (e.g., at +/−45°, the pattern can advantageously define various truss shapes (e.g., comprising triangles and trapezoids) either to be filled-in with support material or not. Still further, it is to be recognized that cutout sections may be set at the exterior of the piece. Doing so can provide grip, tactile indicators or offer other features.
Also, it is to be understood that while the examples show wrapping or rolling a single segmented preform for defining the final structure (when fully bonded), multiple preform pieces or sections can be so employed. For example, one preform may define medial layer(s) with a given cutout pattern and other preforms define inner or outer skin layers.
In addition, the preform may be configured in different manners to achieve the same result. Specifically, depending on fiber orientation, more or less of the material may be fully or semi-bonded in defining a stable structure for wrapping a mandrel. With 0/90° fiber orientation (an example of such shown in the detail in
In any case, the different hockey stick handle configurations 110A, 110B and 110C shown in
It is contemplated that any optional feature of the inventive variations described may be set forth and claimed independently, or in combination with any one or more of the features described herein. Reference to a singular item, includes the possibility that there is a plurality of the same items present. More specifically, as used herein and in the appended claims, the singular forms “a,” “an,” “said,” and “the” include plural referents unless specifically stated otherwise. In other words, use of the articles allow for “at least one” of the subject item in the description above as well as the claims below. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation.
Without the use of such exclusive terminology, the term “comprising” in the claims shall allow for the inclusion of any additional element irrespective of whether a given number of elements are enumerated in the claim, or the addition of a feature could be regarded as transforming the nature of an element set forth in the claims. Except as specifically defined herein, all technical and scientific terms used herein are to be given as broad a commonly understood meaning as possible while maintaining claim validity.
The breadth of the present inventions is not to be limited to the examples provided and/or the subject specification, but rather only by the scope of the claim language. Use of the term “invention” herein is not intended to limit the scope of the claims in any manner. Rather it should be recognized that the “invention” includes the many variations explicitly or implicitly described herein, including those variations that would be obvious to one of ordinary skill in the art upon reading the present specification. Further, it is not intended that any section or subsection of this specification (e.g., the Summary, Detailed Description, Abstract, Field of the Invention, etc.) be accorded special significance in describing the inventions relative to another or the claims. Any of the teachings presented in one section, may be applied to and/or incorporated in another. The same holds true for the teaching of any of the related applications with respect to any section of the present disclosure. The related applications are: Low Weight Reinforced Thermoplastic Composite Goods (US provisional application); Reconfigured Thermoplastic Composite Constructs (US provisional application); Topo-Slice Thermoplastic Composite Components and Products (PCT application); Panel-Derived Thermoplastic Composite Components and Products (PCT application); and Hybrid Thermoplastic Composite Goods (PCT application) each to the assignee hereof and filed on even date, herewith. Moreover, each and every one of these applications is incorporated by reference herein in its entirety for any and all purposes, as are all of the other references cited herein. Should any US published patent application or US patent claim priority to and include the teachings of one or more of the aforementioned US provisional applications, then that US published patent application and that US patent is likewise incorporated by reference herein to the extent it conveys those same teachings. The assignee reserves the right to amend this disclosure to recite those publications or patents by name. Although the foregoing inventions has been described in detail for purposes of clarity of understanding, it is contemplated that certain modifications may be practiced within the scope of the claims to be made.
This application is a continuation of International Application No. PCT/US2012/023014, filed Jan. 27, 2012, which claims priority to U.S. Provisional Application Ser. No. 61/437,492, filed Jan. 28, 2011, both of which are incorporated by reference herein in their entirety for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 61437492 | Jan 2011 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2012/023014 | Jan 2012 | US |
| Child | 13951249 | US |
