Patent Application
20110091702
The present disclosure relates generally to composite products and methods for making composite products.
Historically, composite products having three-dimensional shapes have been difficult and expensive to manufacture. Example composite products may include three-dimensional products having multiple layers, each layer having different properties such as different chemical properties or different mechanical properties. Traditionally, such composite products have been manufactured using lamination-type processes in which different layers having different properties are bonded together. However, different layers having different mechanical properties (e.g., different strengths in compression or tension, different surface textures, different rigidities and different coefficients of thermal expansion) can lead to de-lamination. Furthermore, lamination processes generally involve multiple steps and can be quite time consuming. For example, bonding together different layers having different surface qualities and other mechanical properties typically requires the use of different types of adhesives with different bonding temperatures and curing times. Further, each step in the process generally requires relatively precise control and calibration to ensure a commercially acceptable end product results from the process. This adds to the time, expense and complexity of the processing.
Injection molding processes are also used to manufacture composite products. However, injection molding processes are typically limited in the types of materials that can be utilized. Additionally, injection molding processes often require substantial cleaning operations that take place typically between injections.
One aspect of the present disclosure relates generally to methods for efficiently making composite products, and to composite products made in accordance with such methods.
Another aspect of the present disclosure relates to a compression molding process in which compressible materials and incompressible materials are integrated into a composite product. In one embodiment, a single compression molding step is used to form the composite product.
Another aspect of the present disclosure relates to a compression molding process where first and second materials having different properties are integrated into a composite product in a single step compression operation. In one embodiment, the first material is compressible and flowable, and the second material is incompressible and non-flowable. In such embodiments, the first material can be compressed and concurrently caused to flow around and encapsulate the second material during the single step compression operation.
A further aspect of the present disclosure relates to composite products made through a compression molding process. In certain embodiments, the composite products include incompressible materials enclosed within an encapsulating material. In certain embodiments, the encapsulating material has a construction that allows it to compress in volume and flow relative to the incompressible material at the time the composite product is compression molded. In certain embodiments, the encapsulating material forms a unitary, monolithic and seamless shell, casing, matrix, or skin construction in which the incompressible material is embedded. In one particular embodiment, the encapsulating material includes a binder, a filler and a flow enhancing material.
Certain aspects of the present disclosure relate to a compression molding system that allows for the manufacture of a multi-density composite product having a first material (e.g., a core, a reinforcing material, etc.) that is covered by a skin or matrix made of a second material in a single, shortened press-cycle. In certain embodiments, the skin encapsulates the first material and has a seamless, unitary and monolithic construction. In certain embodiments, the skin provides the composite product with a decorative outer surface. In certain embodiments, the skin is bonded to the first material and encapsulates the first material. In certain embodiments, the composite product is formed by a compression molding process in which materials having different properties are integrated together. In certain embodiments, the materials and degree of compression are selected to provide the composite product with desired properties (e.g., mechanical strength, water resistance, impact resistance, sound deadening, thermal insulating properties, fire proofing, bullet resistance, etc.).
Another aspect of the present disclosure relates to a process that uses a flowable medium with high bonding strength to bond and embed therein one or more elements thereby creating a composite product having a desired a three-dimensional shape. By embedding/encapsulating the elements within the flowable medium and then hardening the flowable medium with the elements embedded therein and bonded thereto, risk of de-lamination is reduced.
Further aspects of the present disclosure relate to a compression molding process where one or more non-compressible elements are incorporated into a composite product having a solid core. One example product of this type can include a panel structure such as a door having one or more internal layers of non-compressible material encapsulated within a seamless, monolithic matrix that surrounds and is bonded to the non-compressible element or elements. Another aspect of the present disclosure relates to a composite product having a generally hollow core surrounded by a composite wall structure having a non-compressible element or elements encapsulated within a seamless, monolithic matrix of encapsulant. Examples of this type of product include a bucket, a casket or portion of a casket, or any other structure including a reinforced composite wall structure defining an inner cavity.
A further aspect of the present disclosure relates to a method for manufacturing a composite product made within a compression cell formed by a female cell component and a male cell component. A press can be used to force the male cell component and the female cell component together. In use, a semi-hydraulic medium can be loaded into the female cell component. By “semi-hydraulic”, it is meant that the medium includes at least some hydraulic characteristics such as flowability and the ability to transfer at least some pressure. One or more incompressible elements (e.g., members, components, structures, sheets, panels, etc.) are also positioned within the compression cell. Examples of incompressible elements include wood products such as wood paneling, plywood or press-board. Other examples of incompressible elements include sheetrock, plaster, aramid yarn reinforced paneling, fiberglass reinforced paneling and other structures. By “incompressible” elements or members, it is meant that the elements or members are relatively less compressible than the semi-hydraulic medium. When the male and female cell components are forced together by the press, the semi-hydraulic medium is compressed in volume and flows to fill voids within the compression cell. Concurrently, the semi-hydraulic medium flows around and encapsulates the incompressible elements.
In certain embodiments, the compression cell can include heating structures (e.g., heating coils) for heating the material within the compression cell as the components of the compression cell are forced together. In this way, the semi-hydraulic medium is melted at the same time it is compressed so that the semi-hydraulic medium flows around and encases the incompressible elements and conforms to the shape of the female cell component.
In certain embodiments, the semi-hydraulic medium is compressed in volume at a ratio of at least 3 to 1 (i.e., a volume reduction of at least 66.7%) during the compression step within the compression cell. In other embodiments, the semi-hydraulic medium is compressed in volume at a ratio of at least 4 to 1 (i.e., a volume reduction of at least 75%), or at least 5 to 1 (i.e., a volume reduction of at least 80%), or at least 6 to 1 (i.e., a volume reduction of at least 83.8%) during the compression step within the compression cell. In contrast, the incompressible elements experience substantially no changes in volume or insignificant changes in volume during the compression step.
It is preferred for the semi-hydraulic medium to constitute an aggregate formed by a mixture of different materials. The mixture can include a bonding agent that causes the semi-hydraulic medium to bond to the incompressible elements. In one embodiment, the mixture includes a filler, a flow enhancer and a flowable binder. Example fillers include sand, saw dust, ground paper, etc. Flow enhancers are preferably capable of melting and flowing upon application of heat and pressure. Example flow enhancers can have a powder, particulate or granular form that changes volume and/or flow characteristics under pressure. Example flow enhancers can include a rubber material such as granular/particulate rubber. An example rubber material includes processed (e.g., ground, chopped, pulverized) tire material. Example binders include thermo-plastics and duro-plastics such as epoxies, urethanes, polyesters, etc. A preferred binder includes methylene diphenyl diisocyanate.
The incompressible elements are generally not flowable and are generally configured so that the incompressible elements do not have meaningful reduction in volume during the compression molding process. By using incompressible elements in combination with a compressible medium, the overall compressibility of the material within the compression cell is reduced as compared to if no incompressible elements were used. In one embodiment, the combination of compressible medium with the incompressible elements has an overall volume compression ratio less than 4 to 1 (i.e., a 75% reduction in volume) and greater than 2 to 1 (i.e., a 50% reduction in volume) during the compression step within the compression cell. The incompressible elements can also be referred to as solid elements (e.g., solid panels, solid members, solid reinforcements). As used herein, a “solid element” means an element that does not flow perceptibly even under moderate stress. The incompressible elements are preferably self-supporting elements. “Self supporting” elements are elements that maintain a three-dimensional shape without support and do not flow to an angle of repose.
In still other embodiments of the present disclosure, a flowable and compressible medium is first loaded into a female cell component. Subsequently, an incompressible element is forced into the flowable and compressible medium with a male cell component that is pressed toward the female cell component (i.e., the incompressible element is plunged or driven into the compressible and flowable medium). As the incompressible element is forced into the compressible and flowable medium, the compressible and flowable medium is compressed in volume and is caused to flow around the incompressible element causing the incompressible element to be encapsulated within the flowable and compressible medium.
As depicted in
As depicted in
In accordance with the principles of the present disclosure, the compression molding apparatus 20 is used to manufacture a composite product in a single compression step. The compression molding apparatus is particularly suited for forming composite products having open tops and hollow interior regions surrounded by a reinforced wall structure.
To manufacture composite product using the compression molding apparatus 20, at least two different types of materials having different mechanical and/or chemical properties are preferably used. For example, as shown at
In use of the compression molding apparatus 20, the semi-hydraulic medium 40 (e.g., a mixture of filler, binder and a flow enhancer) is loaded into the cavity 32 of the second mold component 24 and the incompressible material 42 (e.g., a curved sheet or panel such as a curved wood sheet or sheets) is positioned around the plug portion 36 of the first mold component 22. Next, the semi-hydraulic medium 40 within the second mold component 24 is heated and the first and second mold components 22, 24 are forced together to close the compression cell 26. As the first and second mold components 22, 24 are forced together, the plug portion 36 compresses the semi-hydraulic medium 40 within the cavity 32 causing the semi-hydraulic medium 40 to flow upwardly into the region between the plug portion 36 and the side wall structure 30. Concurrently, the incompressible material 42 is forced downwardly by the first mold component 22 into the semi-hydraulic medium 40 in the region between the plug portion 36 and the side wall structure 30. As the incompressible material 42 is forced downwardly, the incompressible material 42 assists the plug portion 36 in compressing the semi-hydraulic medium 40. The compressed semi-hydraulic medium 40 flows upwardly around the incompressible material 42 such that the semi-hydraulic medium 40 encapsulates the incompressible material 42 as shown at
After the heating and compression step, the semi-hydraulic medium 40 cures or otherwise hardens to form a set shape. Thereafter, the first mold component 22 can be separated from the second mold component 24 (as shown at
As shown at
Referring to
The compression molding apparatus 120 is used in the same manner as the compression molding apparatus 20 described above. For example, the semi-hydraulic medium 40 (e.g., a mixture including components such as a binder, a filler and a flow enhancer) can be positioned within the cavity 132 of the second mold component 124 and the incompressible material 42 (e.g., one or more sheets or panels such as wood sheets) can be positioned around the plug portion 136 of the first mold component 122. The incompressible material 42 can be provided in a rectangular shape that is slightly larger than the rectangular shape of the plug portion 136. To mold the composite product, the semi-hydraulic medium 40 is heated within the second mold component 24 and the first and second mold components 22, 24 are pressed together to drive the plug portion 136 and the incompressible material 42 into the semi-hydraulic medium 40 within the cavity 132 thereby causing the semi-hydraulic medium 40 to be compressed in volume and to flow upwardly around the incompressible material 42 (e.g., into voids located between the incompressible material 42 and the side wall structure 130 and also into voids between the incompressible material 42 and the plug portion 136). As the semi-hydraulic medium 40 is compressed, the material 40 flows into voids within the compression cell 126. Additionally, an outer portion of the semi-hydraulic medium 40 is molded to assume the shape defined by the cavity 132 and an inner portion of the semi-hydraulic medium 40 is molded to assume a shape that is the negative of the plug portion 136.
After the compression process is over and the material 40 has cured or otherwise hardened, the composite product (e.g., the casket structure 146) can be removed from the cavity 132. The resulting casket structure 146 has an integrated construction in which the incompressible material 42 is encased within a matrix 141 formed by the hardened semi-hydraulic material 40. Similar to the matrix 41 forming the bucket 46, the matrix 141 has a monolithic, seamless construction. For example, the matrix 141 includes a bottom portion 141a forming the bottom of the casket structure 146, an inner portion 141b lining the inside of the incompressible material 42, a top portion 141c lining the top of the incompressible material 42 and an outer portion 141d lining the outside of the incompressible material 42. All of the portions 141a-141d are monolithic/unitary with respect to one another such that no seams are provided between any of the portions 141a-141d.
Referring still to
In use of the compression molding apparatus 220, multiple materials can be loaded into the cavity 232. For example, layers of the semi-hydraulic medium 40 (e.g., top, bottom and intermediate layers) can be positioned within the cavity 232. The layers of the semi-hydraulic medium 40 can be separated from one another by layers formed by the incompressible material 42. For example, one incompressible layer 42a can be formed by a wood material such as plywood, pressboard, wood paneling or other material to provide reinforcement to the door 246. Another incompressible material 42b can be provided in another layer within the compression cell 26. The second layer of incompressible material 42b can be adapted to provide the door 246 with other mechanical or chemical properties. For example, the layer 42b can be formed of a fire retardant material such as plaster, an impenetrable material such as Kevlar shielding, a noise deadening material such as glass, foam, or a combination thereof, or other materials having desirable other properties. While two of the layers of incompressible material are shown in
In use of the compression molding apparatus 220, the materials within the compression cell 226 are heated and the first and second mold components 222, 224 are pressed together to cause compression of the layers of semi-hydraulic medium. As the layers of semi-hydraulic medium 40 are heated and compressed, the layers of semi-hydraulic medium 40 flow to fill voids within the compression cell 226. For example, the medium 40 flows to fill voids located between the incompressible layers 42a, 42b and the side wall structure 230. Thus, the layers of semi-hydraulic medium 40 flow to fully encapsulate the incompressible layers 42a, 42b. As so compressed, the outer surface defined by the semi-hydraulic medium 40 conforms to the inner shape of the second mold component 224. Additionally, the decorative film 248 conforms to the decorative shape provided on the bottom side 237 of the extension portion 236 of the first mold component 222. For example, the film 248 conforms to the shape of the recess 239. Furthermore, the semi-hydraulic medium 40 also flows into the recess 239 beneath the film 248 to fill the void and fully support the decorative film 248. Upon curing or otherwise hardening, the semi-hydraulic medium 40 bonds to the decorative film 248 and also bonds to the incompressible layers 42a, 42b to form a relatively rigid, integrated door structure.
