MXPA99001517A - Polymeric compositions and methods for making construction materials from them - Google Patents

Abstract

Polymeric composites are described that can be formed into articles of construction to replace similar articles formed of wood and concrete. The composites comprise a polymer component comprising polyolefins preferably obtained as waste or recycle;a rubbery polymeric component preferably obtained from disposed tires;and a reinforcing filler component comprising mica. The mica is preferably of the expanded variety to allow for a reduction in density over similar composites containing traditional mica. The evaporation of volatile compounds initially contained within the different components, primarily the rubbery polymeric component, allows for the production of articles of construction having a foamed inner core in which the foamed cell structure has not been achieved through the use of traditional CO2 generating foaming agents. Processes for forming the articles of construction are provided that include both extrusion and molding techniques.

Description

POLYMERIC COMPOSITIONS AND METHODS FOR FORMING CONSTRUCTION MATERIALS FROM THEMSELVES FIELD OF THE INVENTION The invention relates generally to the field of mixed polymeric compounds that can be used as building materials. Specifically, the invention relates to mixed polymeric compounds having a polymeric component which is preferably olefin and preferably is recycled, a polymeric rubber component and a reinforcing filler component containing mica. DESCRIPTION OF THE RELATED ART The use of polymeric materials in commerce has increased steadily due to the introduction of some of the first synthetic polymers such as Bakelite. On a volume basis, polyolefins, notably including polyethylene and polypropylene, are one of the most widely produced families of polymers. Its use invades numerous industries, including thick and thin wall packaging, containers, toys, wrapping for wires and cables, automotive parts and medical articles. One of the benefits of using plastic or polymeric materials is the only combination of light weight and strength available with them. The chemical, electrical, physical and other properties of polymeric materials can be modified somewhat to meet the performance criteria for different products. Another benefit of plastic materials is their ease of manufacturing both by molding processes and by extrusion.

In addition, polymeric materials are not readily biodegradable. Because of this, the consumer and industrial articles formed of polymers can have an effective time extension much longer than comparable natural materials. A majority of the polymeric material will often contain several stabilizers including both antioxidants and UV stabilizers to extend its useful life. However, this extension of long life is one of the most negative aspects also supported by the use of polymers. The fact that a very large proportion of polymers, and in particular polyolefins, are used in disposable and short-lived applications, requires that a considerable amount of waste polymer be generated in a short time after it is produced. Until recently, a very large proportion of this waste plastic found its way into the fields. The use of these waste plastics as a component of recycling in products has recently led to marginal reductions in the amount of waste plastic; however, the waste material used in this way is incorporated into articles which by themselves have a relatively short life span. A more effective long-term solution to the increasing volume of waste polymer, particularly polyolefins, would be to use the waste plastic as a component in building materials that require a relatively long life span. Illustrative of long-term construction materials could include railroad junctions, parking rims, marine pivots, floors, or other structures on deck and others. When polymers are used for these purposes, they are usually combined with various other ingredients, such as reinforcement fillers. Polymeric compositions containing a reinforcing filler and which may contain other components are commonly referred to as mixed materials. These mixed materials can be particularly beneficial when used to replace wood. For example, railroad joints based on wood are particularly susceptible to wear and tear due to processes such as erosion. In environments in which the railway junction is subjected to numerous cycles of freezing conditions to those of no freezing, the bond will crack as the water entering the joint freezes and expands. Additionally, wood joints are subjected to insect attack when the creosote treatment is not optimal or when the creosote is removed from the joint. The other way, compared materials formed of mixed materials containing polymers are not so susceptible to water penetration. Finally, the mixed compound can more effectively distribute the stress that results from the penetration, freezing and expansion of water. The ability to distribute stress results in less cracking and warping. The unions of mixed material railroads are not susceptible to insect attack either. Waste polyolefins that are normally used in these building materials or other rigid structural members may contain high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), other polyethylene, polypropylene which includes variations of homopolymers and copolymers (eg, propylene-ethylene copolymers) and combinations of these polymers. Unlike virgin polymers, these waste polymers have undergone at least one heat processing step and often have been exposed to environmental conditions, often for an extended period of time. Because of this, these waste polymers have very different properties than their virgin counterparts. Waste polymers typically have bending strength and lower stress and lower thermal stability than virgin materials. The waste polyolefin component of building materials can often additionally comprise minor amounts, usually less than about 20% of other different polymers including polyvinyl chloride (PVC); chlorinated polyethylene (CPE); sulfonated polyethylene with chlorine; several polymers formed in compound; polystyrene; and various engineering-treated thermoplastics such as polyamides, polycarbonates, thermoplastic polyesters and ABS. The construction materials (or articles) formed of mixed materials containing these waste polymers will usually contain a polymeric material, usually rubber, to add impact resistance and flexibility to the construction article. Any number of polymeric materials can be used for this rubber component, including natural rubber, EPDM, styrene-butadiene rubber and styrene-butadiene-styrene rubber. However, to maintain the goal of reducing the volume of waste deposited in the field, a convenient source of the rubber component is the tires. The tires usually contain rubber, steel; and polyester and other yarns or fibers. Several machines known in the art can be used to cut, grind or crush tires into fragments that can then be used in processes that can form the desired mixed material. Another component that is normally found in these articles is a foaming agent which is used to control the density of the mixed article. A normal foaming agent system will contain a group I metal bicarbonate (alkaline) and a bicarbonate salt of a saturated fatty acid. The alkali metal salts employed include sodium and potassium bicarbonate, while suitable saturated fatty acids include those containing from 14 to 22 carbon atoms. The two compounds react together releasing C02 which forms empty spaces in the solidified mixed material. The empty spaces reduce the density of the final mixed article, thus reducing the amount of raw material required for a given volume of the article, while at the same time increasing the weight resistance ratio of the mixed article. However, the use of these foaming agents can dramatically increase the cost of mixed materials. Additionally, because these foaming agents are used in small amounts, typically less than about 2.0% of the total mixed mass, it is difficult to achieve a homogenous distribution of the foaming agent. As a result, a uniform distribution of empty spaces within the mixed article is difficult to achieve. The non-uniform distribution of empty spaces results in non-uniform weight distribution within the article and non-uniform physical properties. Finally, the addition of the mixed material of a reinforcing filler depending on its morphology and other properties, can improve the properties of tensile strength, impact resistance, stiffness and heat distortion of the mixed material. Reinforcing fillers are often used in conjunction with coupling agents, such as silanes and titanates, to effect incorporation of the filler into the polymer matrix. Reinforcing fillers that have been used for these purposes in various mixed structures include glass fibers, asbestos, volastonite, metal oxide fibers, carbon filaments, talc, kaolin and other clays, mica, calcium carbonate, floating ash and ceramics . Filamentous fillers such as glass fibers typically provide the main properties of impact and tensile strength while the addition of more laminated structures such as talc and mica usually results in increased rigidity and heat distortion. A single filler or multiple fillers can be used depending on the desired properties. Glass fibers in particular are commonly used as a reinforcing filler in mixed materials because it is known that glass fiber will generally improve rigidity without significantly reducing impact properties or increasing density. Nevertheless, glass fibers are normally the most cost prohibitive reinforcing filler and additionally result in significant wear to the processing equipment. As a result, less expensive fillers, such as talc and mica have been used to replace some or all of the glass fibers in a mixed material. Unfortunately, these fillers usually have a much higher density which, therefore, has given as a result, articles of mixed materials heavier than those that use glass fibers. It may be beneficial that mixed materials containing these or other organic fillers instead of, or as a substitute for, a significant portion of fiberglass could have been anticipated to have the density problems indicated above. In addition to the components described above, the mixed materials may contain other additives depending on the intended use of the article. Compatibilizers are often used to effect mixing (i.e., compatibility) of two or more polymers that can comprise the given polymer source in the mixed material. These compatibilizers will normally have reactive groups, which when heated and subjected to shear stress, will react with the polymers via the free radical or ionic mechanisms. The compatibilizers that have been employed include various copolymers of maleic anhydride and one less, acrylate copolymers and ethylene acrylic acid copolymers. The mixed materials may additionally contain antioxidants, UV stabilizers, lubricants, antifungal agents and dyes. These different additives can be added during the manufacture of the article of construction or they can be present in one of the initial polymeric components. SUMMARY OF THE INVENTION According to one aspect of the invention, a polymeric mixed material comprising a polymeric component comprising polyolefins is provided.; a polymeric rubber component comprising particles of approximately 90% by weight will not pass through a 100 mesh screen; and the reinforcing filler component comprising mica. When the expanded mica is used it allows a reduction in density over similar mixed materials that contain traditional mica. The polyolefins of the polymer component are preferably waste or recycled polyolefins. The polymeric rubber component is preferably shredded tire fragments. The polymeric mixed material contains between about 40% and about 75% of the polymer component. The polymer component is thermoplastic in nature and preferably contains polyolefins as a main ingredient. The mixed material further contains between about 4% and about 40% of the polymeric rubber component and between about 6% and about 50% of the reinforcing filler component. According to another aspect of the invention, there is provided a construction article formed of a polymeric mixed material comprising a polymeric component which comprises polyolefins; a polymeric rubber component comprising particles of approximately 90% by weight without passing through a 100 mesh screen; and a reinforcing filler component comprising mica. The article of construction has a foamed internal matrix that is obtained by the evaporation of volatile compounds contained within the mixed material. The main source of these volatile compounds are hydrocarbons and the moisture initially contained within the polymeric rubber component of the mixed material. This method to achieve a foam matrix is contrary to the use of conventional foaming agents such as the combination of an alkali metal bicarbonate and a bicarbonate salt of a saturated fatty acid. Additionally, the internal matrix of the article of construction is distributed more homogeneously than the internal foamed matrices obtained from traditional foaming agents. According to another aspect of the invention, a process for forming a construction article is provided, wherein the article of construction is formed of a polymeric mixed material comprising a polymer component comprising polyolefins; a polymeric rubber component comprising particles of which about 90% by weight will not pass through a 100 mesh screen; and a reinforcing filler component comprising mica wherein the article of construction has a foamed internal matrix which is obtained by the evaporation of volatile compounds contained within the mixed material and wherein the process is selected from the group consisting of extrusion processes and molding. BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other advantages of the invention will be apparent upon reading the following detailed description and by reference to the drawings in which: Figure 1 is a cross section of a construction article formed of a composition of the invention; and Figure 2 is a description of an extrusion apparatus which can be used to form articles of construction of the compositions of the invention. While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example and will be described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms described. Instead, the invention is to cover all modifications, equivalents and alternatives that fall within the spirit and scope of the invention as defined by the appended claims. DESCRIPTION OF SPECIFIC MODALITIES In one modality mixed materials useful as construction materials are provided. The construction materials prepared from the mixed materials of the modality can be used in place of similar materials constructed of wood, concrete or other traditional materials. When formed, the building materials have a substantially solid external surface and a formed matrix that is obtained substantially or completely without the aid of traditional foaming agents. The polymeric mixed compounds contain the following ingredients: a) a polymer component; b) a polymeric rubber component comprising particles of which about 90% by weight will not pass through a 100 mesh screen; and c) a reinforcing filler component. The polymer component is preferably a polyolefin and is additionally preferably obtained as waste recycled material to be distinguished from the virgin polymer. The recycled or waste polymer comes from a variety of sources. The polymer can be subsequently obtained from the consumer of thin-walled containers or flexible packaging. It can be obtained from commercial sources such as defective material from production facilities or disposal of pallets of film making processes. There are numerous other sources of waste or recycled polymer. Discarded or recycled polyolefins which are preferably used as the polymer component to produce the mixed materials of this embodiment include HDPE, LDPE, LLDPE, other polyethylene, polypropylene including variations of homopolymers and copolymers and combinations of these polymers. The waste or recycled polyolefin, as previously indicated, additionally contains minor amounts, usually less than about 20% of other different polymers including polyvinyl chloride (PVC); chlorinated polyethylene (CPE); sulfonated polyethylene with chlorine; several polymers in compound; styrenic polymers; and various engineering-treated thermoplastics such as polyamides, polycarbonates, thermoplastic polyesters and ABS.

The polymeric rubber component is preferably obtained from tires. Tires are cheaper when they are reclaimed after initial use. The tires are preferably in a comminuted state which has been obtained by known methods of cutting, grinding and grinding which may be environmental or cryogenic in nature. The polymeric rubber component adds impact resistance and flexibility to the mixed materials of the modality. Additionally, shredded rubber results in improvements in nail retention characteristics of rail joints formed from the mixed material. Convenient sources of discarded tires in addition to the polymeric rubber material usually contain steel and polyester (or other threads or fiber). For the purposes of this mode, the steel is removed substantially before use, but the polyester present in the tires does not need to be removed. Shredded tire fragments may contain steel shreds, but a substantial presence of aceré will normally result in significant wear and tear on processing equipment. The alternative polymeric rubber component or additionally may contain other materials including natural rubber, EPDM, styrene butadiene rubber, and styrene butadiene styrene rubber. A unique aspect of the mixed material of the present embodiment is that construction articles or building materials formed of mixed material have a foam matrix that is obtained without traditional foaming agents or optionally with a substantial reduction in the amount of foam. traditional foaming agents. The existence of empty spaces in the polymeric matrix allows the reduction in the overall density of the fabricated article of construction. The weight of an article of a given size and shape is reduced and the weight resistance ratio for the article is increased. The empty spaces that make up the foamed matrix are formed when volatile compounds are released from different components of the mixed component during the manufacture of the construction material. The cellular foamed matrix of a representative article of construction of the modality is described in Figure 1. The primary source of these volatiles is the polymeric rubber component. Crushed tire fragments in particular are good sources of these volatile compounds. When heated to a sufficient temperature, they will vary with vapor pressure, the volatile compounds within the pieces of shredded tires, mainly hydrocarbons and moisture, are released via evaporation and become the source of cell formation (ie, empty spaces). or foaming) which is suitable for the appropriate improvements previously described. The density of the article of construction therefore directly refers to the degree of foaming that occurs during manufacture. Because the degree of foaming is directly related to the degree of evaporation of volatile compounds and the degree of evaporation of volatile compounds at pressure and temperature maintained in the extruder or other mixer, it is necessary that the temperature and pressure of the Mixed mixed material is precisely controlled to achieve an article having a homogeneous and desired density therein.

The formation of cells obtained in this way is more homogeneous than the formation of cells obtained mainly by traditional foaming agents because the source of the volatile compounds that produce the cells will generally constitute a larger significant part of the composition than a traditional foaming agent. The polymeric rubber component which is the main source of the volatile compounds will comprise over time as much as about 40% of the mixed material while conventional blowing agents are normally employed in less than 2.0% of the total composition. Additionally, because traditional foaming agents are employed in such low amounts, it is difficult to achieve a homogeneous distribution of these traditional foaming agents, while a homogeneous distribution of the rubber component due to their level of use superior is obtained more easily. The size of the tire fragments used is an important consideration for the foam formation process. Tire fragments should be shredded instead of reduced to fine powders. Tire fragments that have been reduced to fine powders normally, due to fine grinding and drying, do not contain volatile constituent compounds necessary for foaming. Fragments of shredded tires as previously indicated can be obtained from any number of operations, such as cutting, grinding and grinding methods that may be environmental or cryogenic in nature. However, to increase the probability of the release of the necessary amount of volatile compounds, approximately! 90% by weight of the crumbled tire fragments, obtained, however, should not pass through a 100 mesh screen. When other materials such as the polymeric rubber component are used, they should not be in a powdery state or reduced in size to a degree that is removed to a significant portion of any volatile compounds. In the variations of this embodiment, the mixed material may additionally contain some amount of a traditional foaming agent as previously described. However, its use in addition to the described volatile cell formation compound method has not led to further significant reductions in the density of mixed materials. The reinforcing filler component contains mainly mica. When traditional mica is incorporated into mixed polymeric compounds used in building materials the resulting article usually has a specific gravity or density which is often prohibitively very high for many applications. The expanded mica, conversely, can be used to obtain articles of mixed materials that have lower and more acceptable densities. This unique feature is due to the fact that when exposed to high temperatures the mica particle will physically expand to occupy a higher space (ie, a larger volume). The expanded versions of mica can be obtained from various sources such as under the trade name Vermiculite. Therefore, a given mass of expanded mica will occupy a volume greater than the same mass of traditional mica. For example, when the expanded mica is incorporated into a mixed material article of the modality at levels ranging from about 10% to about 30%, a reduction in density ranging from about 5% to about 15% can be obtained on a mixed material that contains the same level of traditional mica. An increase in flexural strength ranging from about 20% to about 30% was additionally observed for mixed materials containing expanded mica. Depending on the desired properties the fiberglass or other fibrous reinforcement fillers may additionally comprise some percentage of the reinforcing filler component. Nevertheless, as previously indicated, the addition of glass fibers under the current economy will result in higher raw material costs. As an alternative, the fibrous components of tires, used as the polymeric rubber component, can provide some effects equal to the glass fiber of the most prohibitive cost. In addition, the additional polyester fiber claimed from the tires can be added as a separate source of reinforcing fiber. The mixed material may contain other fillers, also including traditional mica. Although the inclusion of fillers that have a higher density than the expanded mica will partially combat any method of weight reduction obtained with the expanded mica, there will be cases where an increase in density is convenient.

The mixed material may optionally contain other components depending on the intended use of the article of construction. Although the polymer component, even when obtained as waste or recycled and the polymeric rubber component will normally contain antioxidants to minimize the thermal degradation of the polymer during use, additional antioxidants can be added to the mixed material. The UV stabilizers can additionally be present in an initial component or added during the manufacture of the currently interesting building article. Other additives, including compatibilizers, lubricants, antifungal agents and dyes may be additionally present. The polymeric mixed material of the embodiment contains between about 40% and about 75% of the polymer component. This polymer component is thermoplastic in nature and preferably contains polyolefins as its primary ingredient. The mixed material further contains between about 4% and about 40% of the polymeric rubber component and between about 6% and about 50% of the reinforcing filler component. The mixed material in additional embodiments may contain other additives, such as traditional blowing agents, compatibilizers, colorants and lubricants in an amount of between about 0% and about 6%. In variations of the mode in which both expanded mica and glass fiber are used as ingredients in the reinforcing filler component, the mixed material can contain between about 6% and about 35% expanded mica and between about 0% and around 25% fiberglass. In other modalities, traditional mica can be used together with or as a replacement for expanded mica. In other embodiments, an amount of styrenic polymer can be incorporated into the mixed material that is in addition to any styrenic polymer that may have been contained within the waste or recycle polymer used as the polymer component. As is known in the art, the addition of styrenic polymer to polyolefins usually leads to increases in stiffness in a manufactured article. When the strontium polymer is incorporated in this way, it is used in amounts ranging from about 0% to about 12%. In another embodiment, methods are provided to form the mixed matepal of the previous embodiment in a construction article of a desired shape. As previously indicated, previously known mixed materials have been used to replace wood, concrete and other traditional materials in numerous construction items, including railroad junctions. It is expected that the mixed materials of the above embodiment can be used similarly. As such, any of the polymer processing and manufacturing methods known in the art for producing building materials can be used to produce construction articles formed from the mixed material of the previous embodiment. These methods could include extrusion and molding processes such as injection molding and compression. Extrusion processes are preferred.

In another embodiment the article of construction is formed from the mixed material in an extrusion process described in Figure 2. The extruder apparatus 20 includes a feed section 30, a mixed heating section 40, and a configuration section 50. The The feeding section includes a first feeder 31 having an inlet end 310 and an outlet end 31 1, a second feeder 32 having an inlet end 320 and an outlet end 321 and a third feeder 33 having an end of entrance 330 and an exit end 331. The polymer component preferably selected from polyolefins and still more preferably selected from waste or recycled polyolefins is provided to the inlet end 310 of the first feeder 31. The polymeric rubber component, preferably containing rim fragments which are preferably comminuted to a desired size, are provided at the inlet end 320 of the second feeder 32. The mica-containing reinforcement filler component is provided at the inlet end 330 of the third feeder 33. The use of expanded mica as some portion of the reinforcement filler component. In another embodiment, the reinforcing filler component may additionally contain glass fiber. In yet another embodiment, other additives may be provided to the inlet end 330 of the third feeder 33. In yet another embodiment, a portion of the reinforcement filler component or other additives may be provided to the inlet end 320 of the second feeder 32. heating and mixing section 40 has an infusion end 41 attached to a rotational device 42 which preferably is a motor and an output end 43. Between the drive end 41 and | outlet end 43 there is provided at least one screw 44 having fins that convey material towards the exit end 43 of the mixing section 40. In a preferred embodiment, the extrusion apparatus 20 is a twin screw extruder having two screws 44. This is the configuration described in Figure 2. The material of the feeders 31, 32 and 33 are provided to the mixing and heating section 40 of the exit ends 31 1, 321 and 331 to the entrance doors 410 , 420 and 430. In a preferred embodiment, the inlet port 420 is of screw diameters of about 10 to about 12 downstream of the inlet port 410 and an inlet outlet port 430 is of screw diameters of about 1 8 downstream of the inlet port 420. Heat is applied to the heating and mixing section 40 and controlled via the controller 45. The rotational device 42 rotates the screws 44 that convey the material to the outside. Exit paddle 43. The transportation of the material will result in the mixing of the components and the release of additional heat due to friction. Volatiles expelled during mixing and transport in the mixing and heating section 40 are released at the outlet end 43. The mixed material emerging from the outlet end 43 of the mixing and heating section is pressed through an orifice 51. . The pressure developed in the orifice 51 will normally vary from about 14.06 kg / cm2 to about 70.3 kg / cm2. The mixed material emerges from the orifice in a group of forming dies 52 comprising a hot die section 53 which is attached to the hole 51 and a cooled die section 54 which is adjacent to a cooling bath 55. A fraction device 56 it is placed after the cooling bath to effect the removal of the finished article from the extruder 20. The walls of the die assembly 52 define the shape of the finished article. For example, if a railway junction is desired, the walls of the dice assembly will form a generally rectangular, but not perfectly, shape, which will normally be about 17 inches by about 22.86 inches. The shape of a die used to produce a rectangular article will generally deviate from a real rectangle by having at least two convex dice. It will be readily apparent that the capacity of the extruder apparatus 20 should be sufficient to provide a sufficient amount of the mixed material to fill the entire area of the die group 52. The mixed material emerges from the cooled die section 54 of the die set 52 in the form of the desired article of construction and then passes into the cooling bath 55. After cooling, the external surface of the article is substantially continuous while the article matrix is characterized by a foamed cellular structure. The cooling bath 55 causes the outer surface of the article to solidify. The external surface must be substantially solid in order to avoid deformation of the pulling device 56. Additionally, the speed of the traction device 56 must be maintained in equilibrium with the extrusion regime of the extrusion apparatus 20 to minimize deformation. One way to achieve this is to monitor the expansion pressure of the mixed material exiting the outlet end 43 of the extruder 20. This can be achieved by, for example, monitoring the pressure exerted by the mixed article against the walls of the die set 52. The speed at which the pulling device 56 pulls the mixed material article may vary depending on the changes in this monitored pressure (i.e., increased pulling speed when an increase in pressure above a desired scale is detected and a decreased traction speed when a decrease in pressure of a desired scale is detected). By varying the absorption or traction speed in this manner, a more homogeneous mixed material article with reduced deformation and reduced stress localization can be formed. The finished article emerging from the extrusion apparatus 20 and traction device 56 can be cut to the desired length by an electric saw 60 or a medium cutting means, such as a hot wire which can be optionally placed after the traction device 56. EXAMPLES Four mixed polymeric compounds (AD) dry-fed individual raw materials were prepared via screw feeders calibrated to several feed ports in a Werner double screw extruder &; Fleiderer. In addition to the feed location, revolutions per minute (rpm), amperage and temperature profiles were controlled to achieve mixing, melting, melting and compression mixing.

The extrudate emerging from the extruder was forced through a set of composite configuration dies equipped with internal cooling to achieve a cross section profile of 17.78 cm by 22.86 cm. The solid profiles were extracted from the set of configuration dies and through a cooling water bath by a controllable mechanical pulley. The profiles were cut to approximately 2.7 m sections and allowed to cool further. The physical properties of the articles formed were determined at Wood Sciences Laboratory in the Department of Natural Resources and Enviromental Sciences at the University of Illinois. The laboratory under the direction of Professor Chow, makes costly tests for the railroad industry in the United States and has developed specific devices to handle the full-size cross-junction test. The tests performed are the functional equivalents of ASTM normals for hardness, stiffness, compressive strength and breaking strength. Additional tests with special purpose have been designed and carried out to determine the pressure on the spike and the lateral resistance of the spike. Each article was tested for rigidity and rupture by suspending a 2.7 m specimen on 152.4 cm supports and applying a central load by a mechanical press. The stress-tension or load-deflection curves were generated automatically until the article exceeded its elastic limit and failure. The same mechanical dam was adapted to determine the pressure on the spike (insert resistance in the spike), traction on the spike (withdrawal resistance of spike) and lateral resistance of spike. The conditions of composition and processing and the physical properties of four mixed materials are given in the following tables. Composition of polymeric mixed compounds Processing conditions Physical Properties 0. 5 cm was the approximate elastic limit for mixed materials Selective Properties of the Alcayata The term "n / a" indicates that a measurement for a property was not available.

Claims (29)

1. CLAIMS 1. A polymeric composite comprising: a thermoplastic polymer component comprising a polyolefin, selected from HDPE, LDPE, LLDPE, propylene homopolymer, propylene-ethylene copolymer, and combinations of these polymers; a polymeric rubber component comprising particles with which about 90% by weight will not pass through a 100 mesh screen; and a reinforcing filler component comprising mica, wherein the polymeric composite comprises from about 40% to about 75% of thermoplastic polymer component, from about 4% to about 40% of polymeric rubber component and from about 6% to about 50% reinforcement filler component.
2. 2. The polymeric composite compound of claim 1, wherein the polyolefins are waste or recycled polyolefins.
3. 3. The polymeric composite compound of claim 1, wherein the polymeric rubber component comprises shredded rim fragments.
4. 4. The polymeric composite compound of claim 1, wherein the reinforcing filler component comprises expanded mica.
5. The polymeric composite compound of claim 1, wherein the reinforcing filler component additionally comprises glass fiber.
6. 6. The polymeric composite of claim 1, further comprising a polymeric component.
7. The polymeric composite compound of claim 1, wherein the mixed compound is a rigid structural member.
8. 8. A construction article formed of a polymeric composite comprising: a thermoplastic polymer component comprising a polyolefin, selected from HDPE, LDPE, LLDPE, propylene homopolymer, propylene-ethylene copolymer, and combinations of these polymers; a polymeric rubber component comprising particles with which about 90% by weight will not pass through a 100 mesh screen; and a reinforcing filler component comprising mica; wherein the article of construction has an internal foamed matrix and wherein the polymeric composite comprises from about 40% to about 75% of thermoplastic polymer component, from about 4% to about 40% of polymeric rubber component and from about 6% % to about 50% reinforcement filler component.
9. The article of construction of claim 8, wherein the polyolefins are recycled waste polyolefins.
10. The article of construction of claim 8, wherein the polymeric component of smells comprises crumbled tire fragments. eleven .
11. The article of construction of claim 8, wherein the reinforcing filler component comprises expanded mica.
12. The article of construction of claim 8, wherein the reinforcing filler component additionally comprises glass fiber.
13. 13. The article of construction of claim 8, further comprising a styrenic polymer component.
14. 14. The article of construction of claim 8, wherein the article of construction is a railroad junction. 1 5.
15. A process for forming an article of mixed polymeric composite construction having a foamed internal matrix comprising the steps of: continuously supplying to a hot extruder a thermoplastic polymeric material containing a polyolefin selected from HDPE, LDPE, LLDPE, homopoiimer of propylene, propylene-ethylene copolymer and combinations of these polymers; a polymeric rubber component comprising particles of which about 90% by weight will not pass through a 100 mesh screen; and a reinforcing filler material containing mica; mix the materials in the extruder to form a continuous fusion; and forming and cooling the construction item.
16. The process of claim 15, wherein the step of forming and cooling the article of construction comprises extruding the continuous melt through a group of dice of a shaped section of an extruder apparatus to form the article of construction and cooling the extruded construction item to make it more rigid.
17. 17. The process of claim 16, which further comprises the step of pulling the chilled and rigid construction article through and from the configuration section of the extruder apparatus.
18. The process of claim 15, wherein the step of forming and cooling the article of construction comprises molding the continuous melt into a desired shape.
19. The process of claim 15, wherein the mixed compound is comprised of from about 40% to about 75% of the polymer component, from about 4% to 40% of the polymeric rubber component and from about 6% to about 50 % of the reinforcement filler component.
20. The process of claim 15, wherein the polyolefins are waste or recycled polyolefins. twenty-one .
21. The process of claim 15, wherein the polymeric material comprises fragments of shredded tires.
22. 22. The process of claim 15, wherein the reinforcing filler material comprises expanded mica.
23. 23. The process of claim 15, wherein the reinforcing filler material additionally comprises glass fiber.
24. The process of claim 15, wherein a styrenic polymeric material is additionally provided to the hot extruder.
25. The process of claim 15, wherein the process is an extrusion process using an extruder apparatus having a heating and melting section and wherein the thermoplastic polyimic material, polymeric rubber material and reinforcing filler material is They enter through three different ports placed along the heating and melting section of the extruder.
26. 26. The process of claim 15, wherein the article of construction is a railroad junction.
27. 27. A polymeric composite comprising a thermoplastic polymer component comprising a polyolefin, selected from HDPE, LDPE, LLDPE, propylene homopolymer, propylene-ethylene copolymer and combinations of these polymers; a polymeric rubber component comprising particles with which about 90% by weight will not pass through a 100 mesh screen; and a reinforcing filler component comprising expanded mica.
28. 28. The polymeric composite of claim 27, wherein the polymeric composite comprises from about 40% to about 75% of the thermoplastic polymer component, from about 4% to about 40% polymeric rubber component and from about 6% to about 50% reinforcement filler component.
29. 29. The article of construction of claim 8, further comprising a substantially solid external surface.