The invention relates to the production of forms or similar from foamed metal based on aluminum or other metals. Semi-finished product bodies or similar consisting of a foamable semi-finished product material obtained by compacting a mixture of at least one matrix metal powder and at least one expanding agent which releases a foaming gas are placed into a foaming mould or similar where they are geometrically arranged in the desired manner and then heated to a temperature in the range of melting temperature of the matrix metal. Once the mould has been filled, the foaming process is concluded and the resulting foamed metal forms are shaped out. The invention is characterized in that at least one foamable compacted semi-finished product body is placed into a foaming mould together with at least one structure or functional part or similar consisting of a material which does not foam at the melting temperature of the matrix metal, retained in a desired position and then heated whereby metal foam is produced, said metal foam contact-binding or surrounding the structure or functional part in the form corresponding to the inner cavity of the mould. The metal of the metal foam formed is fully or partially brought into contact with the structure or functional part and after cooling, the composite form obtained is removed form the mould with the structure or functional part bonded in the metal foam.

The present invention relates generally to novel foamed metal moldings, and in particular to a novel process for the specific and reproducible production of these novel moldings.
In recent years a large number of publications and patents have been issued concerning the production of foamed metals, devices for carrying out the process and also concerning the metal/foaming agent mixtures required for foamed metal production or the semifinished products for use in a metal foaming production process and concerning the production of said semifinished product.
Reference is made only by way of example and by no means exhaustively to the following documents with regard to the proposals and activities which have become known in this area.
DE 1 164 102 A, DE 196 12 781 C1, DE 43 40 791A1, DE 44 26 627 A1, EP 460 392 A1, EP588 182A2.
Reference is also to be made here to a known technique of foaming metals, in which semifinished products formed from compacted metal particle/foaming agent particle mixtures are placed in foaming molds, for example of steel, and made to expand by heating.
According to EP 804 982 A2, the powder-metallurgical starting material is heated in a heated chamber outside a foam casting mold and made to expand, after which the metal foam, adjusted in its amount to match the volume capacity of the casting mold, is pressed in its entirety into the casting mold, a relatively complex technique.
In U.S. Pat. No. 3,087,807 A there is a description of a process according to which a semifinished product, formed to correspond approximately in its shape to the desired final form of the finished foamed metal body, is introduced into a hollow enclosure and expanded there by heating.
DE 44 24 15 A1 describes foamed metals with anisotropic properties, which are produced by heating the foamable semifinished product in the foaming and casting mold and subsequent deformation. It is stated there that, for destroying the walls between the pores for the purpose of further reducing their number, said walls representing the means by which the electrical and thermal conduction of the foamed metal, in itself reduced by the pores, takes place, it is possible to provide for the integration of small ceramic or hard-metal particles, short fibers or the like, which serve as crack starters during the deformation.
The number and variability of the application possibilities of foamed metals or of moldings, workpieces, structural elements or the like produced from them is high. Mention is to be made at this point, just as examples, of the stiffening of hollow forms, all structural elements used for sound and vibration damping of the widest variety of types, also structural elements inhibiting energy flows, such as heat flow for example, and not least use as decorative and covering structural elements, increasingly valued on account of their low density, such as for example wall plates and panels or the like, the foam structure itself, or else foam-structure limits within the structural elements, sometimes providing ist surface with attractive esthetic aspects, which may serve for decorative purposes.
In many cases, however, it is a fact that the individual foamed metal molding by itself is not functional and, as for example in the case of soundproofing structural elements, wall panels or the like, requires some sort of securing means or else, for example, is to have cavities, openings or the like, which are intended for example for receiving securing, connecting and/or joining elements.
It is consequently necessary after completion of the foamed metal body to perform finishing work on it, such that the required clearances are made in it, such that, for example, retaining elements have to be screwed into the previously made holes or that clamping and position-retaining elements, for example reaching around the edges of the structural element, have to be attached.
If, for example, foamed metal composite structural elements are to be realized, that is to say for example sandwich structural elements, for example with a lower and upper solid covering metal sheet and a foamed metal structure in between, it has previously been the procedure to introduce a metal powder/foaming-agent powder mixture between the two metal sheets and then produce an essentially compact preform or semifinished body with outer covering layers, for example by rolling, pressing or the like, which body is expanded at elevated temperature, for example in a mold, the bottom sheet then for example remaining in position and the covering sheet being xe2x80x9cliftedxe2x80x9d into a final position by the expanding foamed metal. A disadvantage of this technology, cited here as an example, is that it allows an exact final positioning of the sheets to be achieved only with difficulty.
The object of the invention is to provide a process in which there is essentially no longer any need, such as that described above, for the subsequent provision of structural elements, retaining elements, cavities, clearances or the like. The novel process should, furthermore, save the use of costly-to-produce pre-material, such as for example the semifinished product as described above, on the basis of a compacted metal powder/foaming agent/covering metal sheet composite and should lead to foamed metal products with integrated-in or integrated-on solid elements with exactly controllable final positioning.
The novel process is finally intended to enable the production of finished foamed metal moldings and structural elements suitable right away for technical operation and use, in essentially a single process step.
The invention consequently relates to a novel process for producing moldings, workpieces or structural elements from or with foamed metal on the basis of aluminum or aluminum alloys or other metals or alloys, in which process semifinished bodies, bars, profiles, plates or the like of foamable semifinished material, obtained by powder-metallurgical means by compacting a mixture of at least one powder of the matrix metal with at least one foaming agent which releases a foaming gas at elevated temperature and is base d on at least one metal hydride or some other foaming agent, are introduced into a foaming and shaping mold or the like, are arranged there in the respectively desired geometrical arrangement and two-dimensional and/or three-dimensional distribution, and are brought to a temperature in the range of the melting temperature of the matrix metal in the said mold by heating, the foaming operation is ended after filling of the cavity of said mold to a desired degree with the foamed metal formed and, finally, the foamed metal moldings, workpieces or structural elements obtained in this way are demolded or removed, characterized therein, that
at least one foamable, compacted semifinished body or a plurality of semifinished bodies of this type is/are introduced into the foaming and shaping mold, together with at least one structure or body formed from a material or solid material or metal not foamable at the melting temperature of the matrix metal o r foaming temperature and/or a (technical) functional structural element from the group comprising wires, cables, bars, networks, gratings, foils, plates, sheets, honeycomb bodies, profiles, tubes, bushes, anchoring elements, screw shanks or the like, and is/are held in the desired Position, after which the heating is performed with formation of the foamed metal, enclosing the structure or the (solid) body and/or functional structural element integrally and snugly in the form or shape corresponding to the mold cavity,
the material or matrix metal of the foamed metal formed at the respective foaming temperature being brought into contact with the entire structure or (solid) body and/or functional structural element or with a part of the same, and
after appropriate cooling, the composite molding or structural element obtained, with a structure firmly bonded in the foamed metal, or firmly bonded (solid) body and/or functional structural element, is demolded.
Consequently, the essence of the invention is not only in particular that the foaming operation serves for the forming of the foamed metal itself but also that the foamed metal which develops bonds in situ and integrally with the solid parts, of whatever specific kind they are. Consequently, subsequent material weaknesses, for example due to making holes, threads or the like for the fastening of functional parts, retaining elements or the like can be avoided and the bonding in and anchorage of the solid parts in the finished foamed metal body is achieved to an optimum extent by their in-situ encapsulation in foam.
The individual solid body or functional structural element to be accommodated by the expanding foamed metal can, as expressed above, be entirely surrounded by the foam, whereby the (solid) insert(s) for example provide for a modification of the foam structure. Reinforcing elements for example, such as bars, wires, networks or the like for example, come into consideration for this. However, the foamed metal may also enclose only the anchoring region or the like of a functional structural element, for example a fastening element, the actual functional region extending for example above the surface of the foamed metal body, protruding from it or the like. If metal sheets, that is to say solid bodies with a planar or spatial, but predominantly flat extent are to be joined to the foamed metal, the foamed metal comes to bear in a flat, integrating manner and consequently is integrated flat onto the metal sheet.
A particularly intimate bond between the solid body or plurality of solid bodies and foamed metal can be achieved with a choice of material according to the first embodiment of the invention.
As provided in the case of a second implementational variant of this invention, the individual (solid) body does not have to be produced completely from a metal compatible with the matrix metal of the foamed body which is forming, but rather a coating of the same which promotes material bonding may well suffice, although an integral bond of said coating with the basic body forming its substrate is important.
The invention further comprises as a third variant a selection of materials, material phases, layers or the like coming into consideration for the effective bonding of the (solid) parts into the foamed metal body.
Likewise preferred special cases for the desired high degree of integration of the solid bodies or solid functional structural elements into the foamed metal are respectively shown by the fourth and fifth variants.
In this sense, a number of metals or metal combinations promoting the material bond referred to and specifically directed at the aluminum-based foam matrix metals used to a great extent and with preference are mentioned there as the last variant.
For cases where an intimate bond, as previously dealt with at length, between the foam and the body embedded in the same is not desired, or even subsequent removal of the body is to take place, the measures brought together in the first implementational variant of the invention may bring advantages.
There are in fact no limits to the techniques for applying the coatings promoting or else inhibiting the material bond between the matrix metal and the solid parts encapsulated in the foam of the same. Accordingly, a number of such coating technologies that are particularly preferred within the scope of the invention are mentioned in the second variant according to the invention.
The material bond, in itself essential and desired for most cases, can be supported in an advantageous way by measures for increasing the mechanical bond between the foamed metal and individual solid bodies, as provided for example by enlarging or specially shaping its surface, as provided according to the third preferred embodiment of the invention.
The solid bodies to be integrated into the foam may be produced for example by casting, continuous casting, extrusion molding, extrusion, rolling or the like. For certain cases, for example if the insert structural elements are to meet particularly high technological requirements, that is to say are to have, for example, a high level of hardness, abrasion resistance, chemical resistance or the like, the use of solid bodies or structural elements of material produced by powder-technological means and compacted, for example sintered, is also possible.
Molding or structural elements to be foam-encapsulated of materials with melting temperatures which lie above the melting temperature of the metal of the basic body to be expanded are preferably used.
A major advantage of the novel process of in situ foaming is provided by the first implementational variant specified in claim 5, which consists in that the structures, bodies or functional structural elements to be integrated onto or into the foam of the matrix metal are introduced into the shaping mold together with foamable semifinished bodies, which have essentially a geometry which is similar to the geometry of the finished composite product obtained after foaming.
The disadvantages and problems occurring when, as described above and previously known, the semifinished product used is already in the form of a material composite when it is to be introduced and then expanded together with the solid elements, for example metal sheets, present in the composite, concerning a specific positioning corresponding to the desired final positioning in the finished composite foamed body, have already being briefly discussed above. The process according to the invention provides the major advantage here that it makes it possible for the first time for the solid parts actually to be finally positioned exactly at the desired locations of the foamed body, in a position which is also exact in terms of the angular and spatial attitude, with a procedure such as that provided according to the second embodiment of claim being of particular advantage.
The invention includes a first preferred process variant in which the retaining elements serving for an exact positioning of the solid parts as it were xe2x80x9cgo intoxe2x80x9d the foam matrix, or the like, in other words can be genuinely material-integrated into the same.
To avoid undesired shifting or slipping of the semifinished bodies with respect to one another during the foaming operation, said bodies themselves indeed having to be arranged in the mold before the foaming process quite specifically and preferably in such a way that they match the final form, it has further proven to be particularly favorable to make the semifinished bodies available for the foamed metal formation for instance in the form of mats, bundles or the like held together by metal wires or by filaments of material which is soluble in the matrix metal or for example combustible with essentially no residue; see in this respect the second variant of claim 6, it then just being necessary to follow a procedure in which the mats can be cut to the appropriate length and possibly also width, and the pieces of mat contoured in this way can be introduced directly into the mold, whereby the risk of the semifinished bodies shifting with respect to one another no longer exists. At locations of relatively great foam height, a correspondingly shaped second mat may be arranged on the first mat, etc.
Retaining elements, whatever form they take, with a higher melting temperature than that of the matrix metal forming the foam are preferred.
If it is intended to produce particularly robust sandwich foamed metal bodies with metal sheets or foils respectively bounding the foamed metal bodies above and below or on both sides, which lends the molding particularly high mechanical stability, it is favorable to arrange in the foaming and shaping mold foils and/or metal sheets of this type at the corresponding locations of the in the desired position. This provides the advantage that, for example, an xe2x80x9cupperxe2x80x9d covering foil or a coverage sheet of this type is not arranged, as previously, directly on the body of compacted metal matrix/foaming agent semifinished product arranged on the first sheet, this sheet or foil then being lifted by the foamed metal itself, with increasing pore formation and pore volume enlargement, during the development of the foam, and finally pressed against the top of the mold. Rather, this upper covering foil or upper covering sheet is arranged right away such that it is in the proximity, of, or bears against, the top of the mold, for example by means of appropriate foil holders, so that the aimed for welding with the foamed metal reaching it during the foaming process takes place right away in the desired, exact position.
To obtain a solid body/foamed metal composite molding that is virtually optimum, requires a minimum of finishing effort and is in the final form and final dimension, the charging of the foaming and shaping mold adjusted to match the final form is particularly favorable. In the way specified there, integral foam structural elements of the novel type with largely homogeneous pores can be achieved.
For the production of foamed-metal moldings having pore fractions, pore densities or pore volumes varying locally in regions of their volume, the type of mold charging with the bodies of the foamable semifinished product provided according to the second variant of this claim brings advantages.
For achieving moldings with optimum bonding-in of the solid bodies, it has proven to be particularly advantageous to maintain ratios between the volumes or the total volume of the compacted, foamable semifinished bodies introduced into the mold and the cavity of the shaping mold.
The invention is not in any way restricted to xe2x80x9cfullxe2x80x9d solid bodies, but rather the incorporation of hollow solid bodies, that is to say bodies which are hollow but virtually solid surrounding walls, may also be provided.
A further advantageous possibility consists in that foamed metal bodies are created with clearances, cavities or the like which are accessible from the outside or, for example, also pass through them, which on the one hand saves such empty spaces from subsequently being introduced, but on the other hand has the advantage that the hollow bodies forming the limitation of the empty spaces there provide a significant mechanical reinforcement together with the foamed metal surrounding and integrating them. For example, straight tubular bodies from one wall to the opposite wall of the mold can be foam-encapsulated there tight or, for example, bent tubular bodies from one wall to a neighboring wall of the mold.
In order on the one hand to allow for as high a surface area as possible for the contact of the foamable compacted semifinished material with the mold or mold base provided for heating up, shaping and dimensioning the latter, and on the other hand to avoid undesired slipping or uncontrolled rolling away of the semifinished bodies during manipulation of the mold, and consequently irregular or undesired material density distribution in the mold before foaming, it is favorable according to a third variant of claim 9 to provide a semifinished material with bodies with at least one flat or planar resting side, that is to say underside, by which these semifinished bodies rest on the mold base or a composite metal sheet placed in said mold.
Finally, the invention relates to the composite foamed bodies produced by the novel process.
To sum up, the following is consequently to be stated:
As already mentioned, according to the invention a foamable semifinished product obtained by powder-metallurgical production means is used. The starting product for the production of aluminum foam moldings is, for example, a powder mixture of aluminum or an aluminum alloy, homogeneously mixed with a foaming agentxe2x80x94preferably titanium hydridexe2x80x94and possibly further powder-like additives, which is compacted on a compacting installation, for example a CONFORM system, by pressing, extruding, rolling or in a comparable way, to form piece goods, that is to say bars, plates, profiles or similar semifinished forms, a density of the semifinished product obtainable in this way which preferably lies above approximately 95% of the theoretical density of the metal matrix usually being achieved.
There are known sandwich plates with covering metal sheets, foils or the like applied on one or both sides which have been clad by roll-bonding in a first step, in order finally to join these covering sheets metallically to the metal matrix of the foamable semifinished product, possibly to contour this laminar structure and then, by heating to the melting temperature of the foamable semifinished product, form the foamed body, which is then finally bonded with a material-integrally to the metallic covering sheets; see in this respect, for example, DE 196 12 781 C1.
The following are among the disadvantages of the previously known processes:
a) The roll-bonding cladding just briefly described presupposes that the foamable semifinished product is also available from the outset in plate or sheet form. Such sheet production by powder-metallurgical means is difficult. Known technologies which are available are powder rolling, which however has not so far been successfully developed to the production stage in conjunction with an foamable semifinished product, along with extrusion molding. In extrusion molding, however, there are relatively narrow limits to the profile width, determined by the inside width of the recipient. If an extrusion-molded profile is rolled in the longitudinal direction, the widening of the same produced as a result is inconsiderable. If greater sheet widths are required, the extrusion-molded profile must be cut to length and then introduced transversely into the rolling nip. The production of relatively large amounts of composite plates by transverse rolling is usually rejected, however, by the rolling mills for safety reasons.
b) Structural elements with covering sheets applied on both sides may be either smooth on both sides or they have, for example, contours which are the same as one another on both sides.
c) On sandwich structural elements with covering sheets arranged on both sides, which after roll-bonding cladding and before foaming have xe2x80x9cangularxe2x80x9d contours or cross sections, for example similar to a flat U with lugs protruding away at an angle on both sides, somewhat like this: , the part of the foamable semifinished product in the vertical position cannot expand horizontally. The wall thickness of the foam core is therefore greater in the horizontal positions and less in the vertical positions after expansion. The roll-bonding-clad semifinished product of this type, that is to say a sandwich composite, with contours, can be used only for limited geometries and sizes. With increasing thickness of the expanded structural element, the geometry of the lower and upper covering sheets changes significantly. The semifinished product rolled in between the covering sheets cannot adapt to these changes.
A number of significant points and preferred variants of the process according to the invention are now globally summarized as follows:
1. Covering sheets and foamable semifinished bodies in bar, profile or similar form are placed adjacent to each other and one above each other in a foaming and shaping mold.
2. An upper covering sheet to be integrally bonded to the foamed metal, and a lower covering sheet of this type, may have forms, cross-sectional shapes or topographies which are different from one another without any problem.
3. Foamed sandwich plates can be produced by placing underlying and covering sheets, foils or the like into the mold, without the preparatory or intermediate step of roll-bonding cladding or compacting to form a composite semifinished product, that is to say virtually in one operation.
4. In the case of sandwich foamed metal sheets, the covering sheets consist for example of aluminum or other metals, such as for example steel, Ni-based alloys and their alloys, the melting point of which is for example at least 50xc2x0 C. above the melting point of the semifinished product or matrix metal to be expanded.
5. The foamable semifinished product is preferably formed by profiles produced in a xe2x80x9cCONFORMxe2x80x9d or extrusion-molding installation, preferably with flat or round dimensions, the cross section of which can be adapted overall to the cavity of the mold in such a way that a plurality of profiles are placed adjacent to another or one above each other, the amount, degree of filling and filling height being governed by the desired and aimed for density of the foamed metal structural element respectively to be produced.
6. Foamable semifinished bodies with the same dimensions can be used for different structural elements and different densities and thicknesses. Locally different properties can be achieved in the finished structural element by arrangement of these semifinished inserts at locally different proximities to one another. At the limits between the semifinished bodies or profiles originally is placed into the mold, patterns are produced on the finished foamed metal body or on the surface of the latter and can be used for decorative purposes.
7. To secure adjacent semifinished profiles in the mold against shifting or slipping, it is favorable to use either profiles with at least one flat resting surface, or else profiles or bars to be positioned adjacent to another, or else profiles or bars to be positioned next to one another are joined with the aid of thin metal wires or fibers of various origin, which for example burn without any residuexe2x80x94apart from gas formationxe2x80x94decompose or are dissolved in the molten foamed metal during the foaming operation, to form mats with, for example, uniform distances between the bars, which mats may be prefabricated and precontouredxe2x80x94which significantly simplifies the charging of the moldxe2x80x94when they are placed flat into the mold or locally in layers.
8. The profile cross section of the foamable semifinished product and the position of the bodies to be formed within the mold is advantageously chosen in such a way that the oxide skin located on the surface of the semifinished bodies has sufficient space to break open during the foaming operation, in which the semifinished product of course is initially inflated, so that the nonoxidized metal of the foamed body, liquid in this state, can bond metallically overall to form the foamed body without troublesome oxide skins.
9. The original position of the semifinished bodies used can be seen on the finished plate at its surface and the boundary surfaces between the semifinished bodies, set off in their structure or appearance, can be used as a design element.
10. In the production of sandwich foamed metal plates or the like, the foamed metal is diffusion-welded with a solid covering sheet, previously not yet heated up to the melting temperature, by the effect of the is molten foam front. To improve the metallic bond between the foamed body and the covering sheet or the like, the covering sheet may be clad by rollbonding or coated either with a low-melting alloy, for example AISi12, or with a diffusion-promoting agent, for example zinc. If an intimate bond between the foamed metal and the covering sheet is not desired, release agents, such as for example graphite, an eloxal layer or the like, are favorably applied there.
11. According to an important production variant, the upper covering sheet may be arranged such that it bears against the upper half or top of the mold, or for example is pressed against it, with the aid of spacers or the like, or it is clamped onto it. It can consequently be ensured that the upper covering sheet is already in its final position during the foaming operation and does not first have to be raised by the front of the expanding foam and, as this happens, become for example incorrectly arranged, tilted or the like and is consequently not in the desired final position in the finished foamed body.
Everything stated so far with respect to metal sheets applies analogously to all other forms of structural elements, structures, solid bodies and the like to be integrated into or onto the foamed metal.
An extremely wide variety of integral foam moldings can be produced by the process described above:
i. Plates and sandwich plates which have covering sheets on one side or two sides or have no covering sheets, are plane-parallel or contoured and moldings with covering surface topographies differing from one another.
ii. Moldings of which the hollow interior is xe2x80x9cstiffenedxe2x80x9d with foamed metal.
iii. Upper and lower covering sheets ultimately joined to the foam may be differently contoured, that is to say f or example on the upper side the foamed metal/solid-part composite body may have a corrugated-sheet contour and on the underside it may, for example, be smooth or be provided with a corrugated sheet of some other contour.
iv. By means of semifinished inserts of different densities and the same or different dimensions from one another, different foam thicknesses can be achieved with the same or constant density and (locally) different densities with (locally) different foam thicknesses.
v. For further weight savings, local clearances can be formed in a foam plate to be produced by means of inserts, for example with cavities, that is to say for example pieces of tube, between the covering sheets.
vi. Foamed bodies and end-plate sheets, foils or the like may optionally be securely joined metallically to one another or optionally not be joined to the foamed metal at all or joined in some locations.
vii. An extremely wide variety of solid metal parts, such as tubes and fastening elements, heat exchanging or cooling elements or the like, may be incorporated into the foamed body during foaming.
viii. Foam plates, surrounded by edge strips or covering sheets integrated on one or both sides can be produced. In this case, the peripheral side edges may be formed for example with a channel, produced with the aid of a two-part frame. After the foaming operation, the surrounding frame is swung open and removed. A solid aluminum profile is jammed or adhesively bonded or screwed into the channel produced. The solid profile overlaps with its members the edge of the foam plate and consequently allows a neat formation of the plate edge. This solid-profile frame may also be designed as a connecting piece of two or more is plates joined together at the butt joint, whereby large-area plate structures can also be produced.
A channel provided on the outer sides of the members of the solid aluminum profile can accommodate the edge of a covering sheet, which is pushed into the channel with its edge at right angles. The connection between the covering sheet edge and the solid aluminum profile may be established by adhesive bonding or soldering, welding or else other joining techniques.

Method for producing forms and foamed metal forms

Mepura Metallpulvergesellschaft mbH Ranshofen


The apparatus includes and elongate body having a proximal portion and a distal portion. The body includes a cavity sized to contain a cardiac harness in a compacted configuration and also includes a plurality of elongate push rods movable with respect to the body. The cardiac harness is releasably connected to each of the push rods such that advancement of the push rods in a distal direction moves the harness from a compacted configuration, within the cavity, to an expanded configuration, outside the cavity. The apparatus also includes a releasing member for releasing the connections between the push rods and the harness upon actuation of the releasing member by a user.

1. Field of the Invention
The present invention relates generally to a device and method for delivering a cardiac harness onto the heart of a patient.
2. Description of the Related Art
Congestive heart failure ("CHF") is characterized by the failure of the heart to pump blood at sufficient flow rates to meet the metabolic demand of tissues, especially the demand for oxygen. It has been determined that a passive wrap, or cardiac harness, may increase the efficiency of a heart affected by congestive heart disease. While advances have been made in cardiac harness technology, a satisfactory device and method for delivering and positioning the cardiac harness onto a patient's heart has yet to be provided.
In one method, access to a patient's heart is achieved through an open chest procedure, wherein the sternum is split and separated to allow access to the heart. The cardiac harness is then positioned over the heart by manual manipulation. Such an open chest procedure is highly traumatic to the patient and, thus, remains a relatively undesirable option for cardiac harness delivery.
Present cardiac harness delivery devices do not both adequately retain the cardiac harness onto the delivery device and permit the harness to be easily released from the delivery device. For example, one delivery device utilizes sutures positioned around a circumference of the cardiac harness to secure it to the delivery device. Such arrangements render the cardiac harness difficult to release from the delivery device, especially on the rearward side of the heart. This is because the sutures have to be severed in order to release the cardiac harness from the delivery device. Such an arrangement would not be well suited for a minimally invasive procedure because an additional instrument would have to be introduced to sever the sutures. Furthermore, attaching the cardiac harness to the delivery device only along a circumference tends to apply a localized load to the cardiac harness, which may cause damage to the device.

Cardiac harness delivery device and method


A test sample collection device includes a generally elongated sample collection section for collecting and holding a test sample, a handle member having a top half, a bottom half, a test strip located between the top and bottom halves, and an opening formed by the top and bottom halves, and a cap. Prong members fit within the opening of the handle member for releasably connecting the sample collecting section to the handle member. The cap is releasably mounted on the sample collecting section and covers the sample collecting section. Flexible extension members on the cap are used to release the sample collecting section from the handle member. The collecting section includes a plurality of fins and slots for assisting in collecting the test sample. The device also includes windows for magnified viewing of test results and for indicating whether a sufficient amount of the sample has been collected.

The present invention is directed toward a test sample collection device for an on site test of saliva or other body fluids and more particularly, toward a device that allows for convenient, accurate and simple collection of the sample.
There are many methods that allow for a test sample to be collected in order to analyze the sample. For example, Applicant's prior patent, U.S. Pat. No. 6,372,516 uses an absorbent pad to collect a sample where the pad comes into contact with a test strip from which a reaction, if any, can be seen. Also, Applicant's prior patent, U.S. Pat. No. 7,300,627 uses a spoon-like device to collect a sample.
Another method for collecting fluid samples currently being used and available through Avitar includes a foam head attached to an elongated handle. Attached to the handle is a hood that is movable along the handle. The foam head is placed into a person's mouth so that fluid enters the foam. The hood is slid forward, over the foam head. The hood is squeezed so that fluid contained therein is expelled into a sample well for testing. This device, however, appears to require a great deal of manipulation and handling of the test device by the person taking the test and the person conducting the test.
Also, further testing of a sample may be required. Taking a second test sample may not be desired or feasible. The methods and devices discussed above may allow for multiple tests being conducted at the same time. However, none of these tests allows for preserving the test sample and allowing that sample to be further tested or analyzed. Furthermore, none of the tests discussed above provides an indicator for sample transfer or a magnified view of the test for easy viewing of test results.
Therefore, a need exists for a test sample collection device that is simple to use, provides accurate results in a quick and consistent manner, and allows the test sample to be analyzed further.


An apparatus for illuminating an archer""s arrow that provides a nock adapted to receive a bowstring in a drawn position wherein a light source disposed withing the nock is activated when the bowstring is released from the drawn position. The nock provides a slot which is adapted to receive the bowstring. The slot provides a first widening portion adapted to receive the bowstring in a drawn position, and a second widening portion adapted to receive the bowstring when the bowstring is released from the drawn position. The nock also provides a bore which intersects at least a portion of the second widening portion of the slot. The light source is preferably a chemi-luminescent light stick which fits snugly within the bore of the nock. The bowstring engages and activates the light stick when the bowstring is released from the drawn position.

The present invention relates to an archer""s arrow, and in particular, to an archer""s arrow having a chemical light source that is activated when the arrow is shot from an archer""s bow to illuminate the archer""s arrow.
A long-existing problem for archers has been the difficulty of locating and retrieving an arrow after it has been shot from a bow. During hunting, when an arrow misses its mark, the arrow may land in dense bush, leaves, or the like, making it difficult to locate. When an arrow hits its target, such as an animal, the animal will often travel some distance before falling, sometimes in dense brush or woods. This also makes it difficult to locate the arrow and the animal. The problem of locating the arrow is further accentuated by the loss of light at dusk or after darkness.
Previous arrow designs have attempted to resolve the above-noted problems by providing an electrical light assembly within an arrow nock or within the shaft of the arrow. Such designs have utilized electrical circuits having a lamp, battery, and a switch for closing and opening the electrical circuit to energize and de-energize the lamp, respectively. The disadvantage of such designs is that the electrical circuit, battery, lamp and switch add additional weight to the archer""s arrow which drastically affects the flight of the arrow. In addition, such designs may be susceptible to damage due to the impact the arrow may realize upon the arrow hitting its target. Archers also use arrows for shooting fish, and the electrical circuitry provided in such designs is not practical or operable for use in water and/or other moist and damp environments.
Other designs have utilized chemi-luminescent light sticks to illuminate the nock of an archer""s arrow. Such designs require that the archer activate and insert the chemi-luminescent light stick into the nock prior to shooting the arrow. In fact, activation of the chemi-luminescent light stick typically occurs well before shooting the arrow as such activity would typically xe2x80x9cspookxe2x80x9d the hunted game. This is a disadvantage since the archer must replace the chemi-luminescent light stick to insure that the arrow stays sufficiently illuminated during the time period that an archer may be forced to track an animal it has shot with the arrow. In addition, an illuminated arrow may expose the archer to its game, thereby xe2x80x9cspookingxe2x80x9d the game prior to the archer shooting the animal.
It would be desirable to provide an illuminated archer""s arrow which does not add weight to the arrow. It would also be desirable to provide an illuminated archer""s arrow which is not affected by the environment in which it is utilized. Lastly, it would be desirable to provide an illuminated archer""s arrow which was activated when shot from an archer""s bow.
The present invention relates to an apparatus for illuminating an archer""s arrow. The present invention provides a nock of an archer""s arrow adapted to receive a bowstring in a drawn position. A light source is disposed within the nock and is activated when the bowstring is released from the drawn position. The nock is transparent to allow the illumination of the light source to show through the nock.
The nock provides a slot which is adapted to receive the bowstring and a bore which intersects at least a portion of the slot. The light source, preferably a chemi-luminescent light stick, is disposed within the bore and partially intersects at least a portion of the slot. The light stick is engaged and activated by the bowstring when the bowstring is released from the drawn position.
Other advantages and applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated of practicing the invention is read in conjunction with the accompanying drawings.

Apparatus for illuminating an archer""s arrow


A fiber glass mat adapted to reinforce thermoplastic polymeric molding material is provided with improved flow properties in the molding process without sacrificing strength and without unduly increasing loft of the mat. The improvement is achieved by needling the mat from both sides with the number of needle punches per unit area on one side being greater than that on the opposite side.

The present invention involves improvements in fiber glass mats that are used as reinforcements in thermoplastic composite materials.
Composites of fiber glass reinforcements and thermoplastic matrix materials can be formed by various molding techniques such as compression molding or stamping. The resulting composites can be used in a wide variety of products where a combination of strength and light weight are desired.
The configuration and type of reinforcement significantly effect the physical characteristics of the composite, such as tensile strength, flexural strength, and impact performance. Preferred reinforcement configurations may vary considerably for different molding processes and molding conditions. One known method of varying the physical configuration of a mat is by needling. Needling has several effects on a mat that are beneficial for high flow thermoplastic laminating applications. These include consolidating the mat to enhance mat strength, modifying loft, and rupturing and opening fiber glass bundles to individual filaments. The rupturing and opening functions improve the ability of the glass fiber reinforcement to flow along with the polymeric matrix material when the laminate is molded. In other words, the fiber glass reinforcement has sufficient mobility to be displaced into features of the molded product during the molding process. This, in turn, improves the appearance of the molded composite products. However, known needling techniques are not able to achieve optimization of all of these factors in a single mat. Needling from only one side of a mat is good for strengthening the mat, but it is difficult to achieve sufficient opening of the mat for improved flow without over-punching the mat and sacrificing strength.
Needling a fiber glass mat is known to produce spikes of fibers protruding from the original surface of the mat. U.S. Pat. No. 4,335,176 (Baumann) discloses needling a fiber glass mat through its thickness from one side whereby one side of the mat has more fiber spikes than the other side. The differential is produced by the orientation of barbs on the needles. Because the mat is needled from one side, the number of needle punches is necessarily uniform throughout the mat. The patent discloses assembling two of these mats for lamination.
U.S. Pat. No. 4,885,205 (Wahl et al.) discloses symmetrically needling a mat from both sides so as to reduce needle penetration depth. The objective is to improve appearance of the laminate by reducing the height of the fiber spikes above the original mat surface due to the needling. The emphasis of the disclosure is on making the needling symmetrical on both sides, both in needle penetration depth and needle penetration density. While some improvements are possible with this approach, it has been found difficult to balance tensile strength with good appearance of the molded product using mats made by the method of this patent.
U.S. Pat. No. 5,580,646 (Jansz et al.) discloses needling a mat on both sides, wherein the needling depth or needle type differs from one side to the other. Needle punch density is the same on both sides. The asymmetric mats that are produced are intended to be laminated in pairs. When high flow properties are produced by this method, it has been found that loft is higher than desirable for some applications.
It would be desirable if certain properties of a fiber glass mat could be enhanced for improved thermoplastic composite molding performance with less compromise in other desirable properties as is incurred with prior art approaches.
It has now been found that a fiber glass mat intended for use in reinforcing thermoplastic composites can be provided with a surprisingly advantageous combination of properties by means of a novel needling configuration. The mats of the present invention have a unique combination of good strength, controlled loft, and an enhanced degree of openness for flow during molding. This combination of advantageous properties has been discovered to be attainable by needling the mat from both sides, wherein the needling density (i.e., the number of needle punches per area of mat surface) on one side of the mat differs from that on the other side. The amount of the needling density difference may vary depending upon the desired effect and the details of a particular mat construction and needling operation. Any appreciable difference may be significant, but generally significant advantages are observed when the needle punch density on one side exceeds that on the other side of the mat by more than 5 percent, preferably more than 10 percent. Particularly good results have been obtained by the inventors with preferred commercial mat embodiments when the needling density on one side of the mat is at least 20 percent greater than that on the opposite side of the mat. Optionally, further variations may be used in the needling parameters from one side to the other, such as the needle type and/or needle penetration depth, to achieve further refinements in the mat characteristics. It is particularly advantageous to vary the needling penetration depth in conjunction with the needling density difference. The combination of needling at a relatively deep penetration at relatively low density on one side and needling at a relatively low penetration at relatively high density on the opposite side has been found to be particularly advantageous in achieving improved openness of the mat structure without undue loss of strength.
After needling, the mat may be laminated with thermoplastic resin to form a stampable composite sheet in the usual manner. Unlike some of the prior art, it is not necessary to use two reinforcement mats with the present invention.
Other properties are generally sought after with fiber glass reinforcements including good permeability for impregnation by the thermoplastic matrix material and the ability to yield composite products with good surface smoothness and mechanical properties such as tensile, flexural and compressive strength, tensile and flexural modulus and stiffness. These desirable properties need not be sacrificed in order to attain the advantages of the present invention.
The present invention involves fiber glass reinforcement mats, for which the general manufacturing techniques are well known in the art. The glass fibers used in the mats of the present invention are also those conventionally used in the art. The following description of the fiber forming and mat forming operations are merely examples of processes that may be used for these steps and are included for the sake of completeness of the disclosure of the best mode of carrying out the invention. Additional information regarding these conventional aspects of the invention may be found in K. Loewenstein, The Manufacturing Technology of Continuous Glass Fibres, 3rd Ed. (1993).
The mat is comprised of fibers of known glass compositions based upon oxides such as silica selectively modified with other oxide and non-oxide compounds. Useful glass fibers can be formed from any type of fiberizable glass composition known to those skilled in the art, and include those prepared from fiberizable glass compositions commonly known as xe2x80x9cE-glass,xe2x80x9d xe2x80x9cA-glass,xe2x80x9d xe2x80x9cC-glass,xe2x80x9d xe2x80x9cD-glass,xe2x80x9d xe2x80x9cR-glass,xe2x80x9d xe2x80x9cS-glass,xe2x80x9d as well as E-glass derivatives that are fluorine-free and/or boron-free. Most reinforcement mats comprise glass fibers formed from E-glass. Such compositions and methods of making glass filaments therefrom are well known to those skilled in the art and a more detailed description is not necessary. Further information may be found in Loewenstein (supra), pages 30-44, 47-60, 115-122, and 126-135, which are hereby incorporated by reference.
Commercially produced glass fibers generally have nominal filament diameters ranging from 5.0 to about 35.0 micrometers, and most commonly produced E-glass fibers have a nominal filament diameter of 9.0 to 30.0 micrometers. The present invention may employ any of the commercially available fibers suitable for fabricating in to mats. For further information regarding nominal filament diameters and designations of glass fibers, see Loewenstein (supra) at page 25, which is hereby incorporated by reference.
The glass fibers are conventionally coated on at least a portion of their surfaces with a sizing composition selected for compatibility with the polymeric thermoplastic matrix material. The sizing composition facilitates wet-out and wet-through of the matrix material upon the fiber strands and assists attaining desired physical properties in the composite. Examples of sizing compositions are disclosed in assignee""s U.S. Pat. Nos. 3,997,306 and 4,305,742, which are hereby incorporated by reference. Another sizing composition used commercially comprises a polyepoxide such as EPON(copyright) 880 and a thermosetting polyester material such as RD-847A polyester resin in a ratio of about 1:1 to about 6:1 on a total weight basis as the polymeric film forming materials, and may also include PVP K-30 polyvinyl pyrrolidone, EMERY(copyright) 6717 partially amidated polyethylene imine lubricant, EMULPHOR EL-719 polyoxyethylated vegetable oil, IGEPAL CA-630 ethoxylated octylphenoxyethanol, PLURONIC(trademark) F-108 polyoxypropylene-polyoxyethylene copolymer, SAG 10 anti-foaming material and A-174 functional organo silane coupling agent.
The sizing compositions used here should be compatible with thermoplastic matrix materials. Non-limiting examples of suitable polymeric film-forming materials usable in sizing composition which are compatible with a thermoplastic matrix material include thermoplastic vinyl acetate materials, thermoplastic polyesters, acrylic polymers, polyamides, polyolefins, thermoplastic polyurethanes, vinyl polymers, derivatives and mixtures thereof.
Useful acrylic polymers for use as the film-forming component of a sizing composition include polymers or copolymers of monomers such as acrylic acid; methacrylic acid; esters of these acids such as ethyl, propyl and butyl acrylates and methacrylates; polyglycidyl acrylates and methacrylates; acrylamides; acrylonitriles; and copolymers with unsaturated vinyl compounds such as styrene or vinyl acetate. A few examples of the many commercially available acrylic polymers suitable for this purpose include: FULATEX materials from H.B. Fuller Co. of St. Paul, Minn.; RHOPLEX acrylic emulsions from Rohm and Haas of Philadelphia, Pa.; and CARBOSET acrylic polymers from B.F. Goodrich Co. of Cleveland, Ohio.
Useful polyamides for use as the film-forming component of a sizing composition include the VERSAMID products which are commercially available from General Mills Chemicals, Inc. Suitable thermoplastic polyurethanes are condensation products of a polyisocyanate material and a hydroxyl-containing material such as polyol and include, for example, WITCOBOND(copyright) W-290H which is commercially available from Witco Chemical Corp. of Chicago, Ill. and RUCO 2011L which is commercially available from Ruco Polymer Corp. of Hicksville, N.Y.
Useful polyolefins for use as the film-forming component of a sizing composition include polypropylene and polyethylene materials such as the polypropylene emulsion RL-5440, which is commercially available from Sybron Chemicals of Birmingham, N.J., and Polyemulsion CHEMCOR 43C30, which is commercially available from Chemical Corp. of America.
Generally, the amount of polymeric film-forming material can be about 10 to about 90 weight percent of the sizing composition on a total solids basis, and is preferably about 60 to about 80 weight percent.
The sizing composition can additionally include one or more thermoplastic vinyl polymers, such as polyvinyl pyrrolidones, in an amount which does not detrimentally affect the compatibility of the polymeric film forming materials discussed above with the thermosetting matrix material, if present. Examples of suitable polyvinyl pyrrolidones include PVP K-15, PVP K-30, PVP K-60 and PVP K-90, each of which are commercially available from ISP Chemicals of Wayne, N.J. The thermoplastic vinyl polymer is preferably present in an amount of about 0.5 to about 10 weight percent of the sizing composition on a total solids basis.
The sizing composition preferably further comprises one or more glass fiber lubricants which are different from the polymeric film-forming materials discussed above. As used herein, the phrase xe2x80x9cglass fiber lubricants which are different from the polymeric film-forming materialsxe2x80x9d means that while the glass fiber lubricants may have film-forming properties, the glass fiber lubricant(s) selected for a particular sizing composition are chemically different from the polymeric film-forming materials included in the same coating composition.
Useful glass fiber lubricants include cationic, non-ionic or anionic lubricants and mixtures thereof. Generally, the amount of fiber lubricant can be about 1 to about 25 weight percent of the sizing composition on a total solids basis. Some examples of the many known fiber lubricants include amine salts of fatty acids (which can, for example, include a fatty acid moiety having 12 to 22 carbon atoms and/or tertiary amines having alkyl groups of 1 to 22 atoms attached to the nitrogen atom), alkyl imidazoline derivatives (such as can be formed by the reaction of fatty acids with polyalkylene polyamines), acid solubilized fatty acid amides (for example, saturated or unsaturated fatty acid amides having acid groups of 4 to 24 carbon atoms such as stearic amide), condensates of a fatty acid and polyethylene imine and amide substituted polyethylene imines, such as EMERY(copyright) 6717, a partially amidated polyethylene imine commercially available from Henkel Corporation. A specific useful alkyl imidazoline derivative is CATION X, which is commercially available from Rhone Poulenc of Princeton, N.J. Other useful lubricants include RD-1135B epoxidized polyester which is commercially available from Borden Chemical of Louisville, Ky., CIRRASOL 185A fatty acid amide, KETJENLUBE 522 partially carboxylated polyester which is commercially available from Akzo Chemicals, Inc. Of Chicago, Ill. and PROTOLUBE HD high density polyethylene emulsion which is commercially available from Sybron Chemicals of Birmingham, N.J.
The sizing composition preferably comprises one or more coupling agents selected from the group consisting of organo silane coupling agents, transition metal coupling agents (such as titanium, zirconium and chromium coupling agents), amino-containing Werner coupling agents and mixtures thereof. These coupling agents typically have dual functionality. Each metal or silicon atom has attached to it groups that can react or compatibilize with the glass fiber surface as well as with the components of the sizing composition. As used herein, the term xe2x80x9ccompatibilizexe2x80x9d with respect to coupling agents means that the groups are chemically attracted to, but not necessarily reacted with, the glass fiber surface and/or the components of the sizing composition, for example by polar, wetting or solvation forces.
Examples of suitable organo silane coupling agents include Z-6040 gamma-glycidoxypropyltrimethoxysilane (commercially available from Dow Corning), A-187 gamma-glycidoxypropyltrimethoxysilane, A-174 gamma-methacryloxypropyltrimethoxysilane and A-1100 gamma-aminopropyltriethoxysilane silane coupling agents (each of which are commercially available from OSi Specialties, Inc. of Tarrytown, N.Y.).
The amount of coupling agent can be 1 to about 10 weight percent of the sizing composition on a total solids basis. The organo silane coupling agent can be at least partially hydrolyzed with water prior to application to the glass fibers.
Crosslinking materials can also be included in the sizing composition. Examples of known suitable crosslinkers include melamine formaldehyde and polyamides such as the VERSAMID products commercially available from General Mills Chemicals, Inc. The amount of crosslinker typically ranges from about 1 to about 5 weight percent of the sizing composition on a total solids basis.
The sizing composition may include one or more emulsifying agents for stabilizing the sizing composition in water. Examples of suitable emulsifying agents or surfactants include polyoxyalkylene block copolymers (such as PLURONIC(trademark) F-108 polyoxypropylene-polyoxyethylene copolymer which is commercially available from BASF Corporation of Parsippany, N.J.), ethoxylated alkyl phenols (such as IGEPAL CA-630 ethoxylated octylphenoxyethanol which is commercially available from GAF Corporation of Wayne, N.J.), polyoxyethylene octylphenyl glycol ethers, ethylene oxide derivatives of sorbitol esters and polyoxyethylated vegetable oils (such as EMULPHOR EL-719, which is commercially available from GAF Corp.). Generally, the amount of emulsifying agent can be about 1 to about 30 weight percent of the sizing composition on a total solids basis.
The sizing composition can also include one or more aqueous dispersible or soluble plasticizers to improve flexibility. Examples of suitable non-aqueous-based plasticizers which are aqueous dispersible plasticizers include phthalates, such as di-n-butyl phthalate; trimellitates, such as trioctyl trimellitate; and adipates, such as dioctyl adipate. The amount of plasticizer is preferably less than about 5 weight percent of the sizing composition on a total solids basis.
Fungicides, bactericides and anti-foaming materials and organic and/or inorganic acids or bases in an amount sufficient to provide the aqueous sizing composition with a pH of about 2 to about 10 can also be included in the sizing composition. Water (preferably deionized) is included in the sizing composition in an amount sufficient to facilitate application of a generally uniform coating upon the strand. The weight percentage of solids of the sizing composition generally can be about 5 to about 20 weight percent.
A particular sizing composition for glass fiber strands for reinforcing a thermoplastic matrix material includes EPON(copyright) 880 epoxy resin and RD-847-A polyester resin as the polymeric film forming materials, PVP K-30 polyvinyl pyrrolidone, EMERY(copyright) 6717 partially amidated polyethylene imine lubricant, EMULPHOR EL-719 polyoxyethylated vegetable oil, IGEPAL CA-630 ethoxylated octylphenoxyethanol, PLURONIC(trademark) F-108 polyoxypropylene-polyoxyethylene copolymer, SAG 10 anti-foaming material and A-174 and Z-6040 functional organo silane coupling agents.
The sizing can be applied in many ways, for example by contacting the filaments with a static or dynamic applicator, such as a roller or belt applicator, spraying or other means. For a discussion of suitable applicators, see Loewenstein (supra) at pages 165-172, which is hereby incorporated by reference. Sized filaments may be gathered together into strands. The number of filaments per strand can range from about 100 to about 15,000, more typically about 200 to about 7000. For more information regarding glass fiber strand designations, see Loewenstein (supra) at page 27, which is hereby incorporated by reference.
The sized strands may be dried at room temperature or at elevated temperatures to remove excess moisture and to cure any curable sizing or secondary coating composition that may be present. Drying of glass fiber forming packages or cakes is discussed in detail in Loewenstein (supra) at pages 219-222, which is hereby incorporated by reference. The sizing is typically present on the filaments in an amount ranging from about 0.3 percent to about 1.5 percent by weight after drying.
Although not a preferred practice for the present invention, a secondary coating may be applied to the strands. The secondary coating composition is preferably aqueous-based and may include components similar to the sizing compositions discussed above. The secondary coating composition may be applied to at least a portion of the surface of the strands in an amount effective to coat or impregnate the portion of the strands. The secondary coating can be conventionally applied by dipping the strand in a bath containing the composition, by spraying the composition upon the strand or by contacting the strand with a static or dynamic applicator such as a roller or belt applicator, for example. The coated strand can be passed through a die to remove excess coating from the strand and/or dried as discussed above for a time sufficient to at least partially dry and cure the secondary coating. After drying, it is a common practice for glass fiber intended for mats to be gathered together into roving packages by winding together several generally parallel strands.
Preferably the mats of the present invention are formed from strands which have been chopped into discontinuous lengths. Commercially available choppers may be used, such as Model 90 chopper from Finn and Fram, Inc. Useful apparatus and processes for forming a layer of chopped strands is disclosed in Loewenstein (supra) at pages 293-303, which are hereby incorporated by reference.
An antistatic agent, for example an amine, amide or quaternary salt such as soyadimethyl and ethylammonium ethosulfate, can be applied to the filaments or strands prior to deposition upon the conveyor, if desired.
The mat can be formed using a mat forming apparatus comprising one or more fiber strand supplies, as are known in the art. Preferably, the strand supply comprises a plurality of forming or supply packages mounted upon a creel. Conventional creels suitable for use in the present invention are shown in Loewenstein (supra) at page 315, which is hereby incorporated by reference. The supply packages can be wound such that the strand can be withdrawn from the inside of the supply package or from the outside of the supply package.
The mat can be combined with minor amounts of unidirectional glass fibers, thermoplastic fiber and/or fabrics. The purpose for these additional fibers is to provide temporary strength to the mat during manufacturing prior to laminating. The unidirectional strands can be fed from a creel having a plurality of supply packages to align the unidirectional strands in generally parallel and coplanar alignment. The unidirectional strands and/or fabric can be positioned between layers of the mat or adjacent the top side or bottom side of the mat, as desired. The mat of the present invention may contain fibers that are exclusively glass fibers, but in some cases it is preferred to include, in addition to the glass fibers, a minor amount of fibers that are other than glass fibers (xe2x80x9cnon-glass fibersxe2x80x9d). The non-glass fibers may be blended with the glass fibers in the mat or they may be in the form of a carrier web (e.g., a non-woven fabric) upon which the fiber glass mat is deposited. In some cases the mat may be heated to a temperature at which the non-glass fibers at least partially fuse, thereby binding the mat structure together. A wide variety of commercially available fibers are suitable for this purpose, including synthetic polymers such as polyamides, polyesters, acrylics, polyolefins, polyurethanes, vinyl polymers, derivatives and mixtures thereof.
Non-limiting examples polyamide fibers useful as the supplemental non-glass fiber content of the mat include nylon fibers such as nylon 6 (a polymer of caprolactam which has a melting point of about 223xc2x0 C.) and nylon 6,6 (a condensation product of adipic acid and hexamethylenediamine which has a melting point of about 264xc2x0 C.). Suitable nylons are commercially available from E.I. duPont de Nemours and Company of Wilmington, Del., and BASF Corp. of Parsippany, N.J. Other useful polyamides include aramids such as KEVLAR, which is available from DuPont.
Thermoplastic polyester fibers useful as the supplemental non-glass fiber in the present invention include those composed of at least 85 percent by weight of an ester of a dihydric alcohol and terephthalic acid, such as polyethylene terephthalate, which has a melting point of about 265xc2x0 C. according to Hawley""s Condensed Chemical Dictionary (12th Ed. 1993) at page 934. Examples include DACRON which is available from DuPont, and FORTREL which is available from Hoechst Celanese Corp. of Summit, N.J.
Other fibers which are useful as the supplemental non-glass fiber in the present invention include those formed from acrylic polymers such as polyacrylonitriles having at least about 35 percent by weight acrylonitrile units, and preferably at least about 85 percent by weight, which can be copolymerized with other vinyl monomers such as vinyl acetate, vinyl chloride, styrene, vinylpyridine, acrylic esters or acrylamide.
Useful polyolefin fibers are generally composed of at least 85 percent by weight of ethylene, propylene, or other olefins.
Fibers formed from vinyl polymers which are useful in the present invention can be formed from polyvinyl chloride, polyvinylidene chloride, polytetrafluoroethylene, and polyvinyl alcohol.
Further examples of thermoplastic fiberizable materials which are useful in the present invention are fiberizable polyimides, polyether sulfones, polyphenyl sulfones; polyether ketones, polyphenylene oxides, polyphenylene sulfides and polyacetals.
Other supplemental non-glass fibers that may be present in the mat include natural fibers such as cotton or jute, which may serve as low-cost fillers, and inorganic fibers such as polycrystalline fibers, ceramics including silicon carbide, and carbon or graphite. It should be apparent that the non-glass fibers may include combinations of the fibers described above, as well as fibers formed from blends or copolymers of the materials described above.
The mat can be treated or coated with an adhesive or polymeric binder material to promote consolidation of the mat prior to or after entanglement, although use of a binder is not preferred. Non-limiting examples of useful polymeric binders include polyvinyl acetate, polyesters and polypropylene. Suitable polymeric binders can be in the form of a powder, fiber or emulsion, as desired. The binders are consolidated with the mat by the application of heat and pressure, such as by passing the mat between heated calendering rolls.
After the mat has been formed, it is subjected to a needling process. The glass filaments and glass fiber strands of the mat (as well as any supplemental fibers) are intermeshed by subjecting the mat to a needling process. The needling can be accomplished using a conventional needling apparatus as used in the fiber glass reinforcement industry, wherein the mat is passed between spaced needling boards. An example of such an apparatus is disclosed in assignee""s U.S. Pat. No. 4,277,531 (Picone), which is hereby incorporated by reference. An example of one suitable needling machine is Model NL 9 which is commercially available from Textilmaschinenfabrik Dr. Ernest Fehrer AG of Germany. The mat in the present invention is needled from both sides either by employing a single-sided needling apparatus twice or by using a double sided needler. A particular feature of the present invention is that the needling on one side of the mat is different from that on the opposite side, as will be set forth more fully below.
In the needling operation, a plurality of spaced needles are used to entangle or intertwine the monofilaments and strands of the mat to impart mechanical strength and integrity to the mat. The needling operation may use conventional needles that are constructed with barbs that angle downwardly toward the needle tips, whereby fibers in the mat are entangled as the needles pass downwardly through the mat. On the upward stroke, this needle type generally releases fibers. Although needles with downwardly pointed barbs are preferred, the use of reverse barb needles (i.e., upwardly pointed) is not precluded in the present invention. Although the present invention is not limited to a particular needle configuration, the invention has been successfully carried out with a conventional needle design having three tiers of barb clusters spaced apart along the shaft of the needle, with three barbs in each cluster arranged around the shaft. Preferably, the gauge of the needle ranges from about 32 to about 19 gauge, with a combination of 25 and 32 gauge needles being preferred.
As used herein, the terms xe2x80x9chorizontalxe2x80x9d or xe2x80x9chorizontallyxe2x80x9d refer to a plane generally parallel to the major plane of the mat, which is typically parallel to the ground. As used herein, the terms xe2x80x9cverticalxe2x80x9d or xe2x80x9cvertically,xe2x80x9d xe2x80x9cdownwardly,xe2x80x9d and xe2x80x9cupwardlyxe2x80x9d refer to a direction generally normal to xe2x80x9chorizontal.xe2x80x9d It should be understood that these specific directional terms are used to describe the needling operation for convenience, reflecting the usual orientation of the needling apparatus, and for defining the directions relative to each other, but that these orientations are not limitations on the process.
On the downward needling stroke, the needles of the upper needle board pass through the mat and into generally cylindrical orifices in a backer board supporting the mat. Depending upon the needling depth, one or more of the tiers of barbs pass entirely through the mat and into the backer board orifices. For the purposes of the present invention, when a three-tier needle design is used, it is preferred that at least two tiers of barbs pass through and beyond the mat. Most preferably, all three barb tiers pass through the mat. The distance that the needles pass beyond the mat and into the orifices in the backer board is reported as the xe2x80x9cneedling depth.xe2x80x9d
During upward withdrawal stroke, after the needles exit the mat, they are passed through a plurality of generally cylindrical orifices in a metal stripper plate supported above the mat during the needling process. The filaments and strands are thus pulled from the barb by the stripper plate, and the mat then is advanced in the horizontal direction after the downward and upward stroke of the needle.
The needle board may be reciprocated with a frequency of about 80 to about 3000 strokes per minute (a stroke being a complete downward and upward motion). The needler is provided with rolls to propel the mat in the horizontal direction during needling. At slower frequencies the advancement occurs intermittently in the interval between punches of the needles. At faster frequencies, the advancement approaches a continuous motion.
The length of the needle and the depth of the penetration of the needle through the mat during its passage through the needler, and thus the extent to which the filaments and strands are entangled in a generally vertical direction through the mat affect the impact strength of a composite incorporating the mat as reinforcement.
The depth of penetration of the needles into the orifices of the backer plate may range from about 2 to about 30 millimeters. In a typical needling process, the mat entering the needler may have an overall average thickness of about 2 to about 100 millimeters. After passage throughout the needler, the mat can have a compressed overall average thickness of about 2.5 to about 25 millimeters (about 0.1 to about 1 inches). The needling process is described in further detail in assignee""s U.S. Pat. No. 4,335,176 (Bauman), which is hereby incorporated by reference. The weight of a mat after needling typically ranges from about 200 to about 2000 grams per square meter.
The density of needle punches in a mat is another variable that affects the reinforcement properties of the mat. In general, needle punch density may range from about 6 to about 100 punches per square centimeter (about 40 to about 600 punches per square inch). A particularly advantageous feature of the present invention is that the punch density varies from one side to the other of the mat. The punch density difference may vary in accordance with the properties desired. In theory there is no minimum difference, but appreciable benefits are generally realized when the punch density on one side is at least 5 percent greater on one side than the other, preferably at least 10 percent greater. Particularly advantageous results have been attained with preferred embodiments of mats with a density difference in the range of 20 to 40 percent. Theoretically, no upper limit has been determined, but mechanical limitations may make it difficult to attain differences greater than about 50 percent with a conventional needling apparatus.
The completed mat can be used to reinforce a polymeric matrix material to form a polymeric composite by any method known in the art, for example by compression molding. The selection of the thermoplastic material is not part of this invention; any of the suitable thermoplastic materials employed in the reinforced composite industry may be used. General types of polymeric thermoplastic matrix materials used for this purpose include polyolefins, polyamides, thermoplastic polyurethanes, thermoplastic polyesters, acrylic polymers, vinyl polymers, derivatives and mixtures thereof.
Non-limiting examples of useful polyolefins include polyethylene, extended-chain polyethylene, polypropylene, polybutene, polyisoprene, and polypentene, polymethyl pentene, polytetrafluoroethylene and neoprene.
Useful polyamides include nylons such as nylon 6 (a polymer of caprolactam), nylon 12 (which can be made from butadiene), nylon 66 (a condensation product of adipic acid and hexamethylenediamine), nylon 10 and nylon 12 such as are commercially available from DuPont. Other examples of useful polyamides include polyhexamethylene adipamide and aramids such as KEVLAR, which is commercially available from DuPont.
Suitable thermoplastic polyurethanes are condensation products of a polyisocyanate material and a hydroxyl-containing material such as polyol and include, for example, ESTANE and TEXIN polyurethanes which are commercially available from B.F. Goodrich of Toledo, Ohio and Bayer, respectively.
Thermoplastic polyesters useful in the present invention include polyethylene terephthalate and polybutylene terephthalate. Acrylic polymers useful in the present invention include polyacrylates, polyacrylamides and polyacrylonitriles such as nitrile rubber.
Useful vinyl polymers include polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluoride, ethylene vinyl acetate copolymers, such as ELVAX which is commercially available from DuPont, and polystyrenes.
Thermoplastic elastomeric materials useful as matrix materials in the present invention include styrene-butadiene rubbers, styrene-acrylontrile copolymers such as LUSTRAN, which is commercially available from Monsanto of St. Louis, Mo., styrene-butadiene-styrene copolymers and acrylonitrile-butadiene-styrene copolymers, such as CYCOLAC or BLENDEX, which are commercially available from GE Plastics of Pittsfield, Mass.
Further examples of useful thermoplastic materials include polyimides, polyether sulfones, polyphenyl sulfones, polyetherketones, polyphenylene oxides, polyphenylene sulfides, polyacetals, polyvinyl chlorides and polycarbonates. Also included as suitable thermoplastic materials are any of the above thermoplastics which are modified by an unsaturated monomer.
Other components which can be included with the polymeric matrix material and reinforcing mat in the composite are, for example, colorants or pigments, lubricants or process aids, ultraviolet light (UV) stabilizers, antioxidants, other fillers, and extenders.
The mat and polymeric matrix material can be formed into a composite by a variety of methods that may vary in accordance with the type of polymeric matrix material used and other factors. Thermoplastic composites can be formed by first assembling a laminate of the mat and thermoplastic matrix material and then compression molding or stamping the laminate. To form the laminate, the thermoplastic matrix material can be impregnated into the mat, and then the impregnated mat can be heated in a oven such as a conventional continuous oven at a temperature of about 190xc2x0 C. to about 300xc2x0 C. for about 7 minutes. The laminate can be transferred to a mold and heated under pressure to a temperature which may vary with the resin selected. For example, for polypropylene, the molding temperature can be about 65xc2x0 C. The pressure for forming such a laminate can be about 14 megapascals. One skilled in the art would understand that the laminating and molding temperatures and pressure can vary in accordance with the dimensions and structure of the composite to be formed and the particular thermoplastic matrix material.
A method according to the present invention for making a mat adapted to reinforce a polymeric matrix material entails impregnating with a thermoplastic matrix material at least a portion of a mat that has been asymmetrically needled as described above. The thermoplastic matrix material is heated to a temperature sufficient to permeate the mat and is cooled to ambient temperature to provide a reinforced thermoplastic composite. This composite may subsequently be shaped by stamping or other molding processes as are known in the art.

Double sided needled fiber glass mat for high flow thermoplastic composite