CA2772773A1 - Rubber and rebond composite sheet - Google Patents
Rubber and rebond composite sheet Download PDFInfo
- Publication number
- CA2772773A1 CA2772773A1 CA 2772773 CA2772773A CA2772773A1 CA 2772773 A1 CA2772773 A1 CA 2772773A1 CA 2772773 CA2772773 CA 2772773 CA 2772773 A CA2772773 A CA 2772773A CA 2772773 A1 CA2772773 A1 CA 2772773A1
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- CA
- Canada
- Prior art keywords
- rubber
- rebond
- layer
- masticated
- cured
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
Abstract
A composite sheet comprises a layer of cured rebond material having a first surface and a layer of cured masticated rubber attached to said first surface by heating and pressing the layers together. A method of manufacturing the composite rebond and rubber sheet comprises the steps of: (a) providing a layer of rebond having an outer surface; (b) providing a layer of uncured masticated rubber upon said outer surface, (c) heating and pressing said layers together so as to cure and bond said rubber layer to said outer surface of rebond.
Description
= = CA 02772773 2012-03-28 RUBBER AND REBOND COMPOSITE SHEET
FIELD OF THE INVENTION
The present invention relates to a composite sheet and rolls comprising at least one layer of rubber (which is ultimately cured) and at least one layer of cured rebond material (rubber-crumb and urethane) and a method of manufacturing same.
BACKGROUND OF THE INVENTION
113 It is known to combine layers of uncured rubber to form a dual/multi-density rubber mat under heat and pressure. For example, it is known to provide a composite sheet comprising a layer of uncured rubber faced on one or each side with another layer of uncured rubber firmly bonded to each other.
However, once cured, rubber is very difficult material to bond to other material without some sort of adhesive/chemical bonding agent. Using known techniques, the chemical bonding between a sheet of uncured rubber to an already cured sheet of rubber would be very poor. Previous dual layer rubber products include the vulcanization of uncured-to-uncured rubber layers or utilize the gluing of cured/rebonded layers together.
Nothing in the prior art discloses the use of post industrial and/or post consumer rubber (often referred to as "masticated rubber") combined in a cured rubber-rebond composite sheet being utilizable in various commercial products in an efficient and effective manner.
SUMMARY OF THE INVENTION
It is an object of the present invention to overcome, inter alia, the shortcomings of the prior art described above by providing an improved cured rubber-rebond composite sheet.
= CA 02772773 2012-03-28 In accordance with an aspect of the invention there is provided a rubber-rebond composite sheet comprising a rebond layer having a first surface and a layer of cured masticated rubber attached to said first surface.
In accordance with a further aspect of the invention there is provided a method of manufacturing a composite rebond and rubber sheet comprising the steps of:
(a) providing a layer of rebond having an outer surface;
(b) providing a layer of uncured masticated rubber upon said outer surface, (c) heating and pressing said layers together so as to cure and bond said rubber layer to said outer surface of rebond.
The invention contemplates the formulation of multiple layers such as rebond-masticated rubber-rebond or further layers thereof in various combinations.
In accordance with an aspect of the invention, the layers may be mechanically and /or chemically bonded together.
Various advantageous commercial applications exist for the product of the invention which combine the benefits of both materials (masticated cured rubber being used as a lower unexposed layer having higher hardness, strength, abrasion resistance and rebonded rubber being used as an exposed layer having a lower hardness, being non staining, better visual appearance, lighter weight).
This can be reverse if better abrasion needed.
Other advantages, features and characteristics of the present invention, as well as methods of operation and functions and economies of manufacture, will become more apparent upon consideration of the following detailed description and the appended claims.
DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION
The product in accordance with an aspect of the invention comprises a composite sheet having a layer of cured masticated rubber adhered to a rebond layer (crumb-urethane product).
FIELD OF THE INVENTION
The present invention relates to a composite sheet and rolls comprising at least one layer of rubber (which is ultimately cured) and at least one layer of cured rebond material (rubber-crumb and urethane) and a method of manufacturing same.
BACKGROUND OF THE INVENTION
113 It is known to combine layers of uncured rubber to form a dual/multi-density rubber mat under heat and pressure. For example, it is known to provide a composite sheet comprising a layer of uncured rubber faced on one or each side with another layer of uncured rubber firmly bonded to each other.
However, once cured, rubber is very difficult material to bond to other material without some sort of adhesive/chemical bonding agent. Using known techniques, the chemical bonding between a sheet of uncured rubber to an already cured sheet of rubber would be very poor. Previous dual layer rubber products include the vulcanization of uncured-to-uncured rubber layers or utilize the gluing of cured/rebonded layers together.
Nothing in the prior art discloses the use of post industrial and/or post consumer rubber (often referred to as "masticated rubber") combined in a cured rubber-rebond composite sheet being utilizable in various commercial products in an efficient and effective manner.
SUMMARY OF THE INVENTION
It is an object of the present invention to overcome, inter alia, the shortcomings of the prior art described above by providing an improved cured rubber-rebond composite sheet.
= CA 02772773 2012-03-28 In accordance with an aspect of the invention there is provided a rubber-rebond composite sheet comprising a rebond layer having a first surface and a layer of cured masticated rubber attached to said first surface.
In accordance with a further aspect of the invention there is provided a method of manufacturing a composite rebond and rubber sheet comprising the steps of:
(a) providing a layer of rebond having an outer surface;
(b) providing a layer of uncured masticated rubber upon said outer surface, (c) heating and pressing said layers together so as to cure and bond said rubber layer to said outer surface of rebond.
The invention contemplates the formulation of multiple layers such as rebond-masticated rubber-rebond or further layers thereof in various combinations.
In accordance with an aspect of the invention, the layers may be mechanically and /or chemically bonded together.
Various advantageous commercial applications exist for the product of the invention which combine the benefits of both materials (masticated cured rubber being used as a lower unexposed layer having higher hardness, strength, abrasion resistance and rebonded rubber being used as an exposed layer having a lower hardness, being non staining, better visual appearance, lighter weight).
This can be reverse if better abrasion needed.
Other advantages, features and characteristics of the present invention, as well as methods of operation and functions and economies of manufacture, will become more apparent upon consideration of the following detailed description and the appended claims.
DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION
The product in accordance with an aspect of the invention comprises a composite sheet having a layer of cured masticated rubber adhered to a rebond layer (crumb-urethane product).
= = = CA 02772773 2012-03-28 A first layer of rubber in accordance with this invention is cured masticated rubber. Prior to attachment to the rebond layer, the masticated rubber layer comes in uncured form. Masticated rubber is a blend of uncured friction cord (generally a natural rubber (NR)/ styrene butadiene rubber (SBR) compound calendared onto tire belting) waste from tire manufacturers, uncured NR/SBR compound waste from rubber processors including tire manufacturers, ground up vulcanized tire rubber and fiber from recycled scrap tires, various ground rubber and fiber materials from internally generated waste and typical rubber processing and vulcanizing ingredients. A preferred version of masticated rubber comprises a thermoset rubber blend based on tire belt, tread and sidewall compounds in both cured and uncured form that also contains fiber strands originating from original tire manufacturing, homogeneously dispersed throughout the blend. Additional fabric strands from other sources can also be incorporated to further increase stiffness and tensile strength. The fiber, blended into the masticated rubber mixtures increases stiffness adds strength, increases the modulus and overall hardness of the final product and reduces elongation or stretching of the rubber product. The fibers utilized are typically a mixture of short and long fibers comprised of polyester or nylon or other synthetic polymers. An example of masticated rubber used in accordance with the invention to be cured and bonded to the rebond layer is Symar rubber available from the applicant, National Rubber Technologies Corp. Toronto, Canada.
No adhesive material is disposed between the masticated rubber layer and the rebond layer Crumb / Urethane product (Rebond) composition:
Rebond is made using discarded used tires. Tires are chopped up in small granulate (Crumb) of different sizes (Mesh size) during this process steel and fibers are removed. Then crumb is mixed with small amount of urethane and compressed in a mold with or without heat to cure the mix.
Resulting product is a large cylinder (Log). Using special machine this log . . CA 02772773 2012-03-28 is cut in different thickness in a continuous roll. Colored cured granules can be added to produce a different product appearance.
Advantageously, the heat and pressure conditions utilized to cure masticated rubber sheets may be simultaneously used to bond the masticated rubber layer to the rubber rebond layer. In a preferred process in accordance with the invention, uncured masticated rubber is placed on the outer surface of the rebond sheet. The rubber layer is then simultaneously cured and bonded to the rebond layer. The rebond layer may then be adhered to one side or both sides of the masticated rubber using heat and pressure. Examples of how the rubber layer may be adhered are: (i) by means of a compression molding process, and/or (ii) by means of a continuous cure process.
(i) Compression Molding Process: In an example of a method of forming a composite sheet in accordance with the invention, a standard compression press machine may be utilized to form the composite sheet of masticated rubber and rebond as follows. The rebond, preferably comprising of 85%
to 98% rubber crumb and/or buffings and 2% to 15% urethane. The whole assembly of rebond layers and uncured masticated rubber layers are heated and pressed together. Preferably the rubber-rebond composite is pressed to a thickness of approximately 0.25 inches, although the composite thickness could vary within the range of 0.08 inches to 2 inches if desired. To achieve the best results of adherence of the masticated rubber to rebond in an even manner, the preferred specific pressure applied to the composite would be in the range of 100 psi to 500 psi and the preferred temperature would be between 200 F to 350 F. The preferred duration of application of this heat and pressure is between 2 minutes and 20 minutes. The composite product would be allowed to cool and would have excess rubber trimmed as it exits the press. As desired, a rubber-rebond product having a thickness outside of these ranges could be utilized.
No adhesive material is disposed between the masticated rubber layer and the rebond layer Crumb / Urethane product (Rebond) composition:
Rebond is made using discarded used tires. Tires are chopped up in small granulate (Crumb) of different sizes (Mesh size) during this process steel and fibers are removed. Then crumb is mixed with small amount of urethane and compressed in a mold with or without heat to cure the mix.
Resulting product is a large cylinder (Log). Using special machine this log . . CA 02772773 2012-03-28 is cut in different thickness in a continuous roll. Colored cured granules can be added to produce a different product appearance.
Advantageously, the heat and pressure conditions utilized to cure masticated rubber sheets may be simultaneously used to bond the masticated rubber layer to the rubber rebond layer. In a preferred process in accordance with the invention, uncured masticated rubber is placed on the outer surface of the rebond sheet. The rubber layer is then simultaneously cured and bonded to the rebond layer. The rebond layer may then be adhered to one side or both sides of the masticated rubber using heat and pressure. Examples of how the rubber layer may be adhered are: (i) by means of a compression molding process, and/or (ii) by means of a continuous cure process.
(i) Compression Molding Process: In an example of a method of forming a composite sheet in accordance with the invention, a standard compression press machine may be utilized to form the composite sheet of masticated rubber and rebond as follows. The rebond, preferably comprising of 85%
to 98% rubber crumb and/or buffings and 2% to 15% urethane. The whole assembly of rebond layers and uncured masticated rubber layers are heated and pressed together. Preferably the rubber-rebond composite is pressed to a thickness of approximately 0.25 inches, although the composite thickness could vary within the range of 0.08 inches to 2 inches if desired. To achieve the best results of adherence of the masticated rubber to rebond in an even manner, the preferred specific pressure applied to the composite would be in the range of 100 psi to 500 psi and the preferred temperature would be between 200 F to 350 F. The preferred duration of application of this heat and pressure is between 2 minutes and 20 minutes. The composite product would be allowed to cool and would have excess rubber trimmed as it exits the press. As desired, a rubber-rebond product having a thickness outside of these ranges could be utilized.
= I I a CA 02772773 2012-03-28 =
(ii) Continuous cure process: The masticated rubber layer and the rebond layer may be adhered together using a continuous curing process. The continuous curing process involves an apparatus including conveyor means which advances the rubber and rebond through the apparatus, a heat source and a pressure source which are simultaneously applied to the rubber and rebond as they are advanced through the apparatus, thereby curing and bonding the masticated rubber layer to the rebond. The preferred conveyor means comprises upper and lower stainless steel belts, between which are carried the rebond and masticated rubber layers. In an io example of the continuous curing process, a roll of rebond is positioned horizontally at an entry position to the machine upon the upper and/or lower belt. A roll of uncured masticated rubber is placed adjacent the entry position. A sufficient amount of uncured rubber to cover the rebond layer is dispensed from the roll, and is placed over the upper surface of the rebond layer (or vice versa: rebond on top, masticated rubber on bottom).
The combined rubber and rebond layer are advanced by the moving belts through the press machine. As the rubber and rebond layers are carried between the upper and lower belts, through the continuous press, heat (in the range of 200 F to 350 F) is applied to the rubber and rebond layers. In combination with the heat applied, the lower belt moves the rubber and rebond layers along the machine, and the layers are sandwiched between the upper and lower belts, pressing the rubber to the desired thickness, causing the rubber to be cured and bonded to the rebond layer. To achieve the best results of adherence of rubber to rebond in an even manner, the preferred specific pressure applied to the rubber and rebond layer composite would be 100 psi to 500 psi. Once heated and pressed to the desired thickness, the cured masticated rubber and rebond continues to an exit position where it is allowed to cool and excess rubber is trimmed and the cured masticated rubber-rebond composite material is cut and stacked or rolled. As with the compression molding process, preferably the composite material is pressed to a thickness of approximately 0.250 inches, although the rubber thickness could vary within the range of 0.080 inches to 2 inches if desired.
(ii) Continuous cure process: The masticated rubber layer and the rebond layer may be adhered together using a continuous curing process. The continuous curing process involves an apparatus including conveyor means which advances the rubber and rebond through the apparatus, a heat source and a pressure source which are simultaneously applied to the rubber and rebond as they are advanced through the apparatus, thereby curing and bonding the masticated rubber layer to the rebond. The preferred conveyor means comprises upper and lower stainless steel belts, between which are carried the rebond and masticated rubber layers. In an io example of the continuous curing process, a roll of rebond is positioned horizontally at an entry position to the machine upon the upper and/or lower belt. A roll of uncured masticated rubber is placed adjacent the entry position. A sufficient amount of uncured rubber to cover the rebond layer is dispensed from the roll, and is placed over the upper surface of the rebond layer (or vice versa: rebond on top, masticated rubber on bottom).
The combined rubber and rebond layer are advanced by the moving belts through the press machine. As the rubber and rebond layers are carried between the upper and lower belts, through the continuous press, heat (in the range of 200 F to 350 F) is applied to the rubber and rebond layers. In combination with the heat applied, the lower belt moves the rubber and rebond layers along the machine, and the layers are sandwiched between the upper and lower belts, pressing the rubber to the desired thickness, causing the rubber to be cured and bonded to the rebond layer. To achieve the best results of adherence of rubber to rebond in an even manner, the preferred specific pressure applied to the rubber and rebond layer composite would be 100 psi to 500 psi. Once heated and pressed to the desired thickness, the cured masticated rubber and rebond continues to an exit position where it is allowed to cool and excess rubber is trimmed and the cured masticated rubber-rebond composite material is cut and stacked or rolled. As with the compression molding process, preferably the composite material is pressed to a thickness of approximately 0.250 inches, although the rubber thickness could vary within the range of 0.080 inches to 2 inches if desired.
= . . CA 02772773 2012-03-28 =
Preferably, heat is applied by circulating steam or hot oil through the upper and lower platens of the press. Preferably, hydraulic pressure is applied by means of a hydraulic unit in combination with a plurality of hydraulic cylinders arranged structurally to apply an even force distribution across the width of the platens.
This force distribution acts to press the upper and lower platens of the press together within a specific pressure range, as dictated by the product. The pressing time may vary anywhere from 2 to 20 minutes depending on the desired thickness of the rubber, typically, the thicker the rubber layer, the longer the pressing time.
io There may exist multiple layers of rebond and masticated rubber as part of the product of this invention. It should be further understood that a layer of rebond may be adhered to one or more layers of other types of rubber (eg.
All Natural Rubber).
The product produced in accordance with the invention, namely a cured masticated rubber and rebond product has certain advantageous commercial/industrial applications, as listed below. The cured masticated rubber layer typically has a higher hardness, strength, higher weight, and high abrasion resistance. Masticated rubber can stain (eg. If masticated rubber comes in contact with metal for very long time, it will change the color of metal to yellow). The rebond layer is softer, non-staining and has a more appealing visual appearance. When attached together as a sheet, it is often quite advantageous to have an upper rebond layer exposed to the end user with a lower cured masticated layer below providing strength and weight to the product. Such a configuration is especially desirable in the following applications: athletic flooring, ice rink arena flooring adjacent ice surface, rooftop walkway mats, general floor matting. Other uses of the product of the herein invention may be with truck flaps, truck bed mats. In truck bed mat masticated rubber is exposed as higher abrasion resistance is required.
The above description provides ample information for the person skilled in the art to practice the invention. Furthermore, it will be evident that modifications which are obvious to persons of ordinary skill in the art, may = CA 02772773 2012-03-28 be made without departing from the spirit or scope of the invention, which is accordingly limited only by the claims appended hereto, purposively construed.
Preferably, heat is applied by circulating steam or hot oil through the upper and lower platens of the press. Preferably, hydraulic pressure is applied by means of a hydraulic unit in combination with a plurality of hydraulic cylinders arranged structurally to apply an even force distribution across the width of the platens.
This force distribution acts to press the upper and lower platens of the press together within a specific pressure range, as dictated by the product. The pressing time may vary anywhere from 2 to 20 minutes depending on the desired thickness of the rubber, typically, the thicker the rubber layer, the longer the pressing time.
io There may exist multiple layers of rebond and masticated rubber as part of the product of this invention. It should be further understood that a layer of rebond may be adhered to one or more layers of other types of rubber (eg.
All Natural Rubber).
The product produced in accordance with the invention, namely a cured masticated rubber and rebond product has certain advantageous commercial/industrial applications, as listed below. The cured masticated rubber layer typically has a higher hardness, strength, higher weight, and high abrasion resistance. Masticated rubber can stain (eg. If masticated rubber comes in contact with metal for very long time, it will change the color of metal to yellow). The rebond layer is softer, non-staining and has a more appealing visual appearance. When attached together as a sheet, it is often quite advantageous to have an upper rebond layer exposed to the end user with a lower cured masticated layer below providing strength and weight to the product. Such a configuration is especially desirable in the following applications: athletic flooring, ice rink arena flooring adjacent ice surface, rooftop walkway mats, general floor matting. Other uses of the product of the herein invention may be with truck flaps, truck bed mats. In truck bed mat masticated rubber is exposed as higher abrasion resistance is required.
The above description provides ample information for the person skilled in the art to practice the invention. Furthermore, it will be evident that modifications which are obvious to persons of ordinary skill in the art, may = CA 02772773 2012-03-28 be made without departing from the spirit or scope of the invention, which is accordingly limited only by the claims appended hereto, purposively construed.
Claims (2)
1. A composite sheet comprising a layer of cured rebond material having a first surface and a layer of cured masticated rubber attached to said first surface.
2. A method of manufacturing a composite rebond and rubber sheet comprising the steps of:
(a) providing a layer of rebond having an outer surface;
(b) providing a layer of uncured masticated rubber upon said outer surface, (c) heating and pressing said layers together so as to cure and bond said rubber layer to said outer surface of rebond.
(a) providing a layer of rebond having an outer surface;
(b) providing a layer of uncured masticated rubber upon said outer surface, (c) heating and pressing said layers together so as to cure and bond said rubber layer to said outer surface of rebond.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US201161563641P | 2011-11-25 | 2011-11-25 | |
| US61/563,641 | 2011-11-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2772773A1 true CA2772773A1 (en) | 2013-05-25 |
Family
ID=48464209
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2772773 Abandoned CA2772773A1 (en) | 2011-11-25 | 2012-03-28 | Rubber and rebond composite sheet |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2772773A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016099510A1 (en) * | 2014-12-18 | 2016-06-23 | Compagnie Generale Des Etablissements Michelin | Microstructured composites for improved tire characteristics |
| WO2017024401A1 (en) * | 2015-08-10 | 2017-02-16 | New Rubber Technologies Holdings, Inc. | Method of making a product with composite body and rubber surface |
-
2012
- 2012-03-28 CA CA 2772773 patent/CA2772773A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016099510A1 (en) * | 2014-12-18 | 2016-06-23 | Compagnie Generale Des Etablissements Michelin | Microstructured composites for improved tire characteristics |
| WO2017024401A1 (en) * | 2015-08-10 | 2017-02-16 | New Rubber Technologies Holdings, Inc. | Method of making a product with composite body and rubber surface |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |
Effective date: 20160330 |