CA2202953C - Two-part coated foam structure - Google Patents
Two-part coated foam structure Download PDFInfo
- Publication number
- CA2202953C CA2202953C CA002202953A CA2202953A CA2202953C CA 2202953 C CA2202953 C CA 2202953C CA 002202953 A CA002202953 A CA 002202953A CA 2202953 A CA2202953 A CA 2202953A CA 2202953 C CA2202953 C CA 2202953C
- Authority
- CA
- Canada
- Prior art keywords
- skin
- foamed
- body portion
- polyethylene
- extruded
- 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.)
- Expired - Lifetime
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/20—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of indefinite length
- B29C44/22—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of indefinite length consisting of at least two parts of chemically or physically different materials, e.g. having different densities
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/001—Combinations of extrusion moulding with other shaping operations
- B29C48/0013—Extrusion moulding in several steps, i.e. components merging outside the die
- B29C48/0015—Extrusion moulding in several steps, i.e. components merging outside the die producing hollow articles having components brought in contact outside the extrusion die
- B29C48/0016—Extrusion moulding in several steps, i.e. components merging outside the die producing hollow articles having components brought in contact outside the extrusion die using a plurality of extrusion dies
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
- B29C48/09—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/16—Articles comprising two or more components, e.g. co-extruded layers
- B29C48/18—Articles comprising two or more components, e.g. co-extruded layers the components being layers
- B29C48/21—Articles comprising two or more components, e.g. co-extruded layers the components being layers the layers being joined at their surfaces
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249955—Void-containing component partially impregnated with adjacent component
- Y10T428/249958—Void-containing component is synthetic resin or natural rubbers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249987—With nonvoid component of specified composition
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249987—With nonvoid component of specified composition
- Y10T428/249988—Of about the same composition as, and adjacent to, the void-containing component
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249987—With nonvoid component of specified composition
- Y10T428/249991—Synthetic resin or natural rubbers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249987—With nonvoid component of specified composition
- Y10T428/249991—Synthetic resin or natural rubbers
- Y10T428/249992—Linear or thermoplastic
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249987—With nonvoid component of specified composition
- Y10T428/249991—Synthetic resin or natural rubbers
- Y10T428/249992—Linear or thermoplastic
- Y10T428/249993—Hydrocarbon polymer
Abstract
A foamed polyethylene product has an outer sheath of non-foamed polyethylene fused to an underlying foamed body portion. Preferably, the product is produced in an in-line method when the foam body is extruded and subsequently the skin is extruded directly on the body portion. This process only causes limited thermal degradation of an outer layer of the body portion which improves adhesion of the skin to the body portion.
Description
CA 022029~3 1997-04-17 TITLE: TWO-PART COATED FOAM STRUCTURE
FIELD OF THE INVENTION
The present invention relates to foamed plastic products and in particular to foamed plastic products having an outer protective skin which is extruded onto a resilient foamed product. The present invention is also directed to a method of manufacturing of the product.
BACKGROUND OF THE INVENTION
Various types of foamed plastic products are known and many of these products are produced by an extrusion process and produce a body portion which is relatively soft and resilient. Foamed polyethylene extruded products have been used for pipe insulation and have also been applied about structural members to provide a resilient outer cushion member. For example, foamed polyethylene cushion members have been applied to supports of gymnastic equipment, playground equipment, football standards and basketball poles to reduce the possibility of injury by striking of the structural member.
Foamed polyethylene can be extruded in a number of different shapes and is very valuable for the type of applications described above. Unfortunately, the product is relatively soft, and thus, the outer surface can tear easily, even though there is a very thin skin portion produced at the outer surface of the product during the extrusion process. To overcome this problem, fabric or tape have been applied about the product, and thus, provides a further surface which protects the underlying polyethylene from damage.
It would be desirable to have a foamed polyethylene product which has a tougher outer surface and one which can be produced in a cost effective manner.
Some solutions to the above problem have been proposed and one such solution involves using a separately foamed cylindrical sheath, which when exposed to heat shrinks about a product. The outer sleeves are placed CA 022029~3 1997-04-17 WH-9~3 5US
about a polyethylene foamed product and then heat is applied to the sheath which then contracts to the diameter of the foamed polyethylene. This results in a two-stage process to marry the polyethylene foamed body and the outer sheath and it also re~uires somehow placing the foamed polyethylene body within the outer sheath. Examples of these types of structures and other arrangements are disclosed in United States Patent 3,607,497, United States Patent 3,813,272, United States Patent 3,832,260, United States Patent 4,634,615, United States Patent 4,776,803, United States Patent 4,780,158, United States Patent 4,861,412, United States Patent 4,950,352 and United States Patent 5,360,048.
The present invention seeks to address the problems outlined above and produce a product which can be produced at a lower cost.
SUMMARY OF THE INVENTION
A polyethylene product according to the present invention comprises a foamed body portion of polyethylene in combination with an outer skin of non-foamed thermal plastic polyethylene which is fused to the foamed body portion.
According to an aspect of the invention, the foamed body portion has a boundary layer which has undergone thermal degradation and acts as an intermediary securing by heat sealing the outer skin to the body portion.
According to a further aspect of the invention, the skin includes a significant amount of colour pigment and the body portion has no appreciable or consistent colour pigment.
According to a further aspect of the invention, the skin of the product includes a significant amount of colour pigment and is of a colour unrelated to the body portion.
According to a further aspect of the invention, the outer skin includes a significant amount of ultraviolet stabilizers and the body portion does not have any significant amounts of ultraviolet stabilizers.
CA 022029~3 1997-04-17 According to a further aspect of the invention, the polyethylene product with the body portion and the outer skin is of a generally cylindrical shape with an open central cavity which is placed about an elongate member, such that the elongate member is within the cavity whereby the polyethylene product provides an outer resilient sheath about the elongate body member.
A method of manufacturing, according to the present invention, produces a foamed polyethylene product having an outer tough sheath about a foamed polyethylene body portion. The method comprises extruding the foamed polyethylene body portion of a desired cross section, partially cooling the extruded body portion, and subsequently extruding a thin thermal plastic skin directly onto the body portion, resulting in fusing or heat sealing of the skin to an upper layer of the body portion, which due to the heat of the extruded skin, causes limited collapse of a boundary layer of the foamed body portion and securement of the skin to the body portion.
According to an aspect of the invention, the step of extruding the skin is conducted in-line with the step of extruding the polyethylene body portion and prior to complete cooling of the polyethylene body portion.
According to a further aspect of the invention, the method includes a step where the polyethylene body portion is pulled through a cylindrical extruding die which applies the extruded skin to the foamed body portion as it is pulled through the die.
According to a further aspect of the invention, the extruding die applies a skin having a thickness of approximately .003 inches.
According to a further aspect of the invention, the foamed body and the skin are of different colours.
According to yet a further aspect of the invention, the cylindrical die includes a control arrangement for adjusting the extrusion discharge rate from the cylindrical die and the method includes adjusting of the control arrangement to produce a desired outer skin thickness.
CA 022029~3 1997-04-17 BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention are shown in Figure 1, which is a schematic view of the two-stage in-line extrusion process;
Figure 2 is a cross sectional view of the foamed polyethylene body after the first stage of the extrusion process; and Figure 3 is a cross sectional view of the final product.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
There are many known arrangement for extruding foamed polyethylene product and one such extruder is shown as 2 in the Figure. Product leaves the die of the extruder at 4 and almost immediately foams to full product dimensions, as generally indicated at 6. Thus, the foamed product 6, shortly downstream of the extruding die, is still relatively hot, but the outer skin 7 has formed and cooling is generally occurring from the outside in. Often, the extruded foamed polyethylene is exposed to cooling air or water cooling to reduce the time necessary to reduce the general temperature of the polyethylene foam. This foam has low thermal conductivity and this characteristic extends the time period required to fully cool the product.
In any event, shortly downstream of the extrusion die 4, the polyethylene foamed product passes through the cross head sheath extruder 8. This extruder is basically a cylindrical ring through which the polyethylene foam is pulled and the cross head extrudes a skin onto the outer surface of the polyethylene foam using the foam for support.
Surprisingly, it was found that the cross head sheath extruder 8 can extrude a skin 11 directly onto the foamed polyethylene body 6 to produce the skinned product 14. Extruding of the skin onto the body portion 14 only causes a limited amount of thermal degradation in the polyethylene foam body, which thermal degradation assists in adhering or fusing the skin 11 to the body portion. It CA 022029~3 1997-04-17 WH-9435tlS
would seem that the excellent thermal insulating properties of the foamed body portion protect the underlying layers of the foamed body portion from the higher temperatures of the hot skin and allow sufficient time for the skin to cool.
There is no appreciable collapse or loss in the overall shape of the product. In this way, there is very little damage to the foamed body portion and a tough, preferably polyethylene skin can be easily applied about the foamed body portion.
Figure 2 slows the foamed product 6 before extruding the skin on the product and Figure 3 shows the skinned polyethylene product 14.
A further feature of the present invention is the reduction in colour pigment that may be possible, in that the outer skin can have a very rich colour while the foamed body can be of a completely different colour or be essentially void of any colour pigment. Furthermore, if the foamed core was made of recycled material, the colour of the body portion does not matter, as the outer sheath provides the finished surface.
Another advantage of the present invention is using this method to first extrude the polyethylene foamed body and then apply a polyethylene outer skin to the foamed body. Any waste product is of polyethylene and as such, can be recycled and reused as part of the material for extruding the polyethylene foamed body. Therefore, there is no waste material, as any scrap product can be recycled.
The outer skin can be of a material other than polyethylene such as polypropylene, surlyn, ethylene vinyl acetate, or other extrudable materials which, when extruded in this manner, become sufficiently secured to the polyethylene foam body.
The cross head sheath extruder 8 can have different cross heads for different types of product, for example larger product or smaller product, and different cross heads for different cross sections of product.
The foamed body portion 6 need not have a solid core and can have an open center, as would be the case with CA 022029~3 1997-04-17 WH-9q35US
pipe insulation. This shape is most appropriate for feeding over an elongate structural member, such as a metal tube member or pipe member, and is particularly useful as a cover support member for a play structure. For example, it would be useful in protecting the support pole of a basketball hoop, for providing protection around a roll bar, for providing protection around play structures which have tubular members, such as climbing structures, and other similar types of applications.
The outer sheath also provides a very tough layer which allows other uses for the polyethylene foamed body portion. For example, this could be useful for boat bumpers or protective strips where the outer skin provides a toughness to the product which overcomes the problems associated with tearing of merely the body portion if it was used alone.
Another advantage of the present product is that the colour pigment can be concentrated in the outer skin and the inner foamed body does not need to have any particular colour pigment. This results in a cost saving and also allows a simple way to easily change the colour of the product during extrusion. For example, the line could be extruding one product having a black coating and at an appropriate time, the raw material for the cross head extruder could be replaced with a different raw material having a different colour pigment. There would be a short overlap where some scrap product may have to be recycled as the cross head extruder basically finishes extruding with the one colour and starts extrusion with the next, but the extrusion line can basically continue to run and there is no requirement to deal with changing colour regarding extruding of the foamed body portion.
A further advantage is that W stabilizers can be placed in the outer skin and the inner foamed body does not need these stabilizers. This is important with respect to pipe insulation where the stabilizers significantly contribute to the cost of the product. By concentrating these W stabilizers in the outer skin, i.e. the portion CA 022029~3 1997-04-17 which is exposed to the sun, the body portion can be absent of these stabilizers in many cases, causing no appreciable effect on longevity of the product.
Although various preferred embodiments of the present invention have been described herein in detail, it will be appreciated by those skilled in the art, that variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims.
FIELD OF THE INVENTION
The present invention relates to foamed plastic products and in particular to foamed plastic products having an outer protective skin which is extruded onto a resilient foamed product. The present invention is also directed to a method of manufacturing of the product.
BACKGROUND OF THE INVENTION
Various types of foamed plastic products are known and many of these products are produced by an extrusion process and produce a body portion which is relatively soft and resilient. Foamed polyethylene extruded products have been used for pipe insulation and have also been applied about structural members to provide a resilient outer cushion member. For example, foamed polyethylene cushion members have been applied to supports of gymnastic equipment, playground equipment, football standards and basketball poles to reduce the possibility of injury by striking of the structural member.
Foamed polyethylene can be extruded in a number of different shapes and is very valuable for the type of applications described above. Unfortunately, the product is relatively soft, and thus, the outer surface can tear easily, even though there is a very thin skin portion produced at the outer surface of the product during the extrusion process. To overcome this problem, fabric or tape have been applied about the product, and thus, provides a further surface which protects the underlying polyethylene from damage.
It would be desirable to have a foamed polyethylene product which has a tougher outer surface and one which can be produced in a cost effective manner.
Some solutions to the above problem have been proposed and one such solution involves using a separately foamed cylindrical sheath, which when exposed to heat shrinks about a product. The outer sleeves are placed CA 022029~3 1997-04-17 WH-9~3 5US
about a polyethylene foamed product and then heat is applied to the sheath which then contracts to the diameter of the foamed polyethylene. This results in a two-stage process to marry the polyethylene foamed body and the outer sheath and it also re~uires somehow placing the foamed polyethylene body within the outer sheath. Examples of these types of structures and other arrangements are disclosed in United States Patent 3,607,497, United States Patent 3,813,272, United States Patent 3,832,260, United States Patent 4,634,615, United States Patent 4,776,803, United States Patent 4,780,158, United States Patent 4,861,412, United States Patent 4,950,352 and United States Patent 5,360,048.
The present invention seeks to address the problems outlined above and produce a product which can be produced at a lower cost.
SUMMARY OF THE INVENTION
A polyethylene product according to the present invention comprises a foamed body portion of polyethylene in combination with an outer skin of non-foamed thermal plastic polyethylene which is fused to the foamed body portion.
According to an aspect of the invention, the foamed body portion has a boundary layer which has undergone thermal degradation and acts as an intermediary securing by heat sealing the outer skin to the body portion.
According to a further aspect of the invention, the skin includes a significant amount of colour pigment and the body portion has no appreciable or consistent colour pigment.
According to a further aspect of the invention, the skin of the product includes a significant amount of colour pigment and is of a colour unrelated to the body portion.
According to a further aspect of the invention, the outer skin includes a significant amount of ultraviolet stabilizers and the body portion does not have any significant amounts of ultraviolet stabilizers.
CA 022029~3 1997-04-17 According to a further aspect of the invention, the polyethylene product with the body portion and the outer skin is of a generally cylindrical shape with an open central cavity which is placed about an elongate member, such that the elongate member is within the cavity whereby the polyethylene product provides an outer resilient sheath about the elongate body member.
A method of manufacturing, according to the present invention, produces a foamed polyethylene product having an outer tough sheath about a foamed polyethylene body portion. The method comprises extruding the foamed polyethylene body portion of a desired cross section, partially cooling the extruded body portion, and subsequently extruding a thin thermal plastic skin directly onto the body portion, resulting in fusing or heat sealing of the skin to an upper layer of the body portion, which due to the heat of the extruded skin, causes limited collapse of a boundary layer of the foamed body portion and securement of the skin to the body portion.
According to an aspect of the invention, the step of extruding the skin is conducted in-line with the step of extruding the polyethylene body portion and prior to complete cooling of the polyethylene body portion.
According to a further aspect of the invention, the method includes a step where the polyethylene body portion is pulled through a cylindrical extruding die which applies the extruded skin to the foamed body portion as it is pulled through the die.
According to a further aspect of the invention, the extruding die applies a skin having a thickness of approximately .003 inches.
According to a further aspect of the invention, the foamed body and the skin are of different colours.
According to yet a further aspect of the invention, the cylindrical die includes a control arrangement for adjusting the extrusion discharge rate from the cylindrical die and the method includes adjusting of the control arrangement to produce a desired outer skin thickness.
CA 022029~3 1997-04-17 BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention are shown in Figure 1, which is a schematic view of the two-stage in-line extrusion process;
Figure 2 is a cross sectional view of the foamed polyethylene body after the first stage of the extrusion process; and Figure 3 is a cross sectional view of the final product.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
There are many known arrangement for extruding foamed polyethylene product and one such extruder is shown as 2 in the Figure. Product leaves the die of the extruder at 4 and almost immediately foams to full product dimensions, as generally indicated at 6. Thus, the foamed product 6, shortly downstream of the extruding die, is still relatively hot, but the outer skin 7 has formed and cooling is generally occurring from the outside in. Often, the extruded foamed polyethylene is exposed to cooling air or water cooling to reduce the time necessary to reduce the general temperature of the polyethylene foam. This foam has low thermal conductivity and this characteristic extends the time period required to fully cool the product.
In any event, shortly downstream of the extrusion die 4, the polyethylene foamed product passes through the cross head sheath extruder 8. This extruder is basically a cylindrical ring through which the polyethylene foam is pulled and the cross head extrudes a skin onto the outer surface of the polyethylene foam using the foam for support.
Surprisingly, it was found that the cross head sheath extruder 8 can extrude a skin 11 directly onto the foamed polyethylene body 6 to produce the skinned product 14. Extruding of the skin onto the body portion 14 only causes a limited amount of thermal degradation in the polyethylene foam body, which thermal degradation assists in adhering or fusing the skin 11 to the body portion. It CA 022029~3 1997-04-17 WH-9435tlS
would seem that the excellent thermal insulating properties of the foamed body portion protect the underlying layers of the foamed body portion from the higher temperatures of the hot skin and allow sufficient time for the skin to cool.
There is no appreciable collapse or loss in the overall shape of the product. In this way, there is very little damage to the foamed body portion and a tough, preferably polyethylene skin can be easily applied about the foamed body portion.
Figure 2 slows the foamed product 6 before extruding the skin on the product and Figure 3 shows the skinned polyethylene product 14.
A further feature of the present invention is the reduction in colour pigment that may be possible, in that the outer skin can have a very rich colour while the foamed body can be of a completely different colour or be essentially void of any colour pigment. Furthermore, if the foamed core was made of recycled material, the colour of the body portion does not matter, as the outer sheath provides the finished surface.
Another advantage of the present invention is using this method to first extrude the polyethylene foamed body and then apply a polyethylene outer skin to the foamed body. Any waste product is of polyethylene and as such, can be recycled and reused as part of the material for extruding the polyethylene foamed body. Therefore, there is no waste material, as any scrap product can be recycled.
The outer skin can be of a material other than polyethylene such as polypropylene, surlyn, ethylene vinyl acetate, or other extrudable materials which, when extruded in this manner, become sufficiently secured to the polyethylene foam body.
The cross head sheath extruder 8 can have different cross heads for different types of product, for example larger product or smaller product, and different cross heads for different cross sections of product.
The foamed body portion 6 need not have a solid core and can have an open center, as would be the case with CA 022029~3 1997-04-17 WH-9q35US
pipe insulation. This shape is most appropriate for feeding over an elongate structural member, such as a metal tube member or pipe member, and is particularly useful as a cover support member for a play structure. For example, it would be useful in protecting the support pole of a basketball hoop, for providing protection around a roll bar, for providing protection around play structures which have tubular members, such as climbing structures, and other similar types of applications.
The outer sheath also provides a very tough layer which allows other uses for the polyethylene foamed body portion. For example, this could be useful for boat bumpers or protective strips where the outer skin provides a toughness to the product which overcomes the problems associated with tearing of merely the body portion if it was used alone.
Another advantage of the present product is that the colour pigment can be concentrated in the outer skin and the inner foamed body does not need to have any particular colour pigment. This results in a cost saving and also allows a simple way to easily change the colour of the product during extrusion. For example, the line could be extruding one product having a black coating and at an appropriate time, the raw material for the cross head extruder could be replaced with a different raw material having a different colour pigment. There would be a short overlap where some scrap product may have to be recycled as the cross head extruder basically finishes extruding with the one colour and starts extrusion with the next, but the extrusion line can basically continue to run and there is no requirement to deal with changing colour regarding extruding of the foamed body portion.
A further advantage is that W stabilizers can be placed in the outer skin and the inner foamed body does not need these stabilizers. This is important with respect to pipe insulation where the stabilizers significantly contribute to the cost of the product. By concentrating these W stabilizers in the outer skin, i.e. the portion CA 022029~3 1997-04-17 which is exposed to the sun, the body portion can be absent of these stabilizers in many cases, causing no appreciable effect on longevity of the product.
Although various preferred embodiments of the present invention have been described herein in detail, it will be appreciated by those skilled in the art, that variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims.
Claims (36)
1. A method of manufacturing an elongate composite of indeterminate length comprising a composite of a soft foamed hollow polyethylene body portion of a desired cross-section and a continuous integral outer non-foamed skin comprising the steps of:
first continuously extruding the foamed hollow body along an axial length thereof;
then, partially cooling the extruded foamed hollow body;
followed by continuously extruding the outer non-foamed skin coaxially around the foamed hollow body while ensuring a skin temperature to effect thermal degradation and collapse of the foam of an outer boundary layer of the foamed body to bond the skin to the body to form the composite without appreciable collapse or loss in the overall cross-sectional shape of the composite.
first continuously extruding the foamed hollow body along an axial length thereof;
then, partially cooling the extruded foamed hollow body;
followed by continuously extruding the outer non-foamed skin coaxially around the foamed hollow body while ensuring a skin temperature to effect thermal degradation and collapse of the foam of an outer boundary layer of the foamed body to bond the skin to the body to form the composite without appreciable collapse or loss in the overall cross-sectional shape of the composite.
2. A method as claimed in claim 1 wherein extrusion of said body portion produces a foam having no significant UV stabilizers and said thermal plastic skin contains significant UV stabilizers forming a protection layer about said foamed body portion.
3. A method as claimed in claim 2 wherein said method includes guiding said body portion through a cross head extruder having a cavity to loosely receive the body allowing said body to be drawn through said cross head extruder and engaging the product downstream of the cross head extruder and pulling said body portion through the cross head extruder.
4. A method as claimed in claim 3 including cooling of the product after discharge from said cross head extruder.
5. A method as claimed in 4 wherein said cross head extruder extrudes the plastic of said skin through a ring orifice onto said foamed body portion.
6. A method as claimed in claim 5 wherein said ring orifice is controlled to produce a skin thickness approximately .003 inches.
7. A method as described in claim 6, wherein said step of extruding a foamed polyethylene body portion produces a tubular foamed polyethylene body portion having a center cavity extending along said axial length of the body portion.
8. A method as claimed in claim 7 wherein the product is pulled through a cross head extruder and the product is cooled after discharge from the cross head extruder.
9. A method as claimed in claim 8 wherein said cross head extruder includes a ring orifice for applying a polyethylene skin and said ring orifice is controllable to vary the skin thickness.
10. A method of manufacturing a two part structure having a foamed polyethylene member with an outer skin comprising:
extruding a foamed polyethylene body portion of a desired cross-section along an axial length thereof, partially cooling said extruded body portion and subsequently coaxially extruding a thermal plastic skin directly around said body portion, to fuse said skin coaxially to the outside surface of said body portion.
extruding a foamed polyethylene body portion of a desired cross-section along an axial length thereof, partially cooling said extruded body portion and subsequently coaxially extruding a thermal plastic skin directly around said body portion, to fuse said skin coaxially to the outside surface of said body portion.
11. A method as claimed in claim 10 wherein said polyethylene body portion is pulled through a cylindrical extruding die which applies said extruded skin to said body portion as said polyethylene body portion is pulled through said die.
12, A method as claimed in claim 11 wherein said extruding die applies a skin having a thickness of approximately .003 inches.
13. A method as claimed in claim 12 wherein said foamed body and said skin are of different colours.
14. A method as claimed in claim 13 wherein said desired cross-section is circular.
15. A method as claimed in claim 14 wherein said outer skin includes significant amounts of ultraviolet stabilizers.
16. A method of manufacturing a foamed plastic member extruded along an axial length thereof and having an outer skin comprising:
extruding a foamed plastic core of a desired cross-section along an axial length thereof; and applying a thermal plastic skin coaxially around said foamed plastic portion to heat seal said skin to said foamed plastic core; said skin supported by said extruded foamed plastic core.
extruding a foamed plastic core of a desired cross-section along an axial length thereof; and applying a thermal plastic skin coaxially around said foamed plastic portion to heat seal said skin to said foamed plastic core; said skin supported by said extruded foamed plastic core.
17. A method as claimed in claim 16 wherein said skin thickness is about.003 inches.
18. A method as claimed in claim 17 wherein said foamed plastic core comprises foamed polyethylene.
19. A method as claimed in claim 18 wherein said thermal plastic skin is selected from the group of polypropylene, surlyn, ethylene vinyl acetate.
20. A method as claimed in claim 19 wherein said foamed plastic core is solid.
21. A method as claimed in claim 20 wherein said skin is supported solely by said extruded foamed hollow body.
22. A method as claimed in claim 21 wherein said skin is extruded directly unto and solely supported by said partially cooled body.
23. A method as claimed in claim 22 wherein the heat of said extruded skin effects said thermal degradation and collapse of said outer boundary layer of said foamed body to bond said skin to said body.
24. A method as claimed in claim 23 wherein said skin is supported solely by said extruded foam polyethylene body portion.
25. A method as claimed in claim 24 wherein said extruded skin is at a temperature to effect limited collapse of a boundary layer of said foamed core to heat seal said skin to said core.
26. A method as claimed in claim 25 wherein said skin comprises a material selected from the group of non-foamed thermo polyethylene, polypropylene, surlyn, and ethylene vinyl acetate.
27. A method of manufacturing an elongate composite of indeterminate length comprising: a composite of a soft foamed hollow polyethylene body portion of a desired cross-section and a continuous integral outer non-foamed skin comprising the steps of continuously extruding the foamed hollow body along an axial length thereof; partially cooling the extruded foamed hollow body; continuously extruding the outer non-foamed skin through a ring orifice coaxially around the foamed hollow body while ensuring a skin temperature to effect thermal degradation and collapse of the foam of an outer boundary layer of the foamed body to bond the skin to the body to form the composite without appreciable collapse or loss in the overall cross-sectional shape of the composite wherein said ring orifice is controlled to produce a skin thickness approximately 0.003 inches.
28. A method as claimed in claim 27 wherein extrusion of said body portion produces a foam having no significant UV stabilizers and said skin contains significant UV stabilizers forming a protective layer about said foamed body portion.
29. A method as claimed in claim 27 wherein said method includes guiding said body portion through a cross head extruder having a cavity to loosely receive the body allowing said body to be drawn through the cross head extruder and engaging the product downstream of the cross head extruder and pulling said boy portion through the cross head extruder.
30. A method as claimed in claim 27 wherein said cross head extruder extrudes the plastic of said skin through a ring orifice onto said foamed body portion.
31. A method as claimed in claim 27 wherein said ring orifice is controllable to vary said skin thickness.
32. A method of manufacturing a two part structure having a foamed polyethylene member with an outer skin comprising: extruding a foamed polyethylene body portion of a desired cross-section along an axial length thereof, partially cooling said extruded body portion and subsequently coaxially extruding a thermal plastic skin directly around said body portion, to fuse said skin coaxially to the outside of said body portion; wherein said polyethylene body portion is pulled through a cylindrical extruding die which applies said extruded skin to said body portion as said polyethylene body portion is pulled through said die wherein said extruding die applies a skin having a thickness of approximately 0.003 inches.
33. A method of manufacturing a foamed plastic member extruded along an axial length thereof and having an outer skin comprising: extruding a foamed plastic core of a desired cross-section along an axial length thereof; and applying a thermal plastic skin coaxially around said foamed plastic portion to heat seal said skin to said foamed plastic core; wherein the skin thickness is about .003 inches.
34. A method as claimed in claim 33 wherein the heat of said skin effects thermal degradation and collapse of said outer boundary layer of said foamed body to bond said skin to said body.
35. A method as claimed in claim 34 wherein said extruded skin is at a temperature to effect limited collapse of a boundary layer of said foamed core to heat seal said skin to said core.
36. A method as claimed in claim 35 wherein said skin comprises a material selected from the group consisting of non-foamed thermo polyethylene, polypropylene, surlyn, and ethylene vinyl acetate.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/633,943 US6497919B1 (en) | 1996-04-17 | 1996-04-17 | Two-part coated foam structure |
| US08/633,943 | 1996-04-17 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2202953A1 CA2202953A1 (en) | 1997-10-17 |
| CA2202953C true CA2202953C (en) | 2001-12-25 |
Family
ID=24541799
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002202953A Expired - Lifetime CA2202953C (en) | 1996-04-17 | 1997-04-17 | Two-part coated foam structure |
Country Status (2)
| Country | Link |
|---|---|
| US (3) | US6497919B1 (en) |
| CA (1) | CA2202953C (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6497919B1 (en) * | 1996-04-17 | 2002-12-24 | Industrial Thermo Polymers Limited | Two-part coated foam structure |
| US6613406B1 (en) | 1996-08-13 | 2003-09-02 | Neocork Technologies, Llc | Multilayer synthetic stopper |
| JP4161473B2 (en) * | 1999-07-01 | 2008-10-08 | 豊田合成株式会社 | Extruded product with insert and method for producing the same |
| US6592789B2 (en) * | 2001-05-18 | 2003-07-15 | James B. Barsby | Apparatus and methods for mixing and injecting a foam core within an extruded shell |
| EP1312458A1 (en) * | 2001-11-16 | 2003-05-21 | Antonino Cucinella | Method and apparatus for the production of plastic extruded profiles |
| US6790112B2 (en) | 2003-01-21 | 2004-09-14 | Captain Noodle, Inc. | Recreational floatation device with integral cup holder |
| US20080248887A1 (en) * | 2007-04-03 | 2008-10-09 | The Shane Group | Method of crating a fall-safe, synthetic turf-covered play area |
| ES1066228Y (en) * | 2007-06-12 | 2008-04-01 | Vera Felipe Mora | ANTILESION SPORTS PORTERS WITH NORMALIZED REBOUND |
| US20110045415A1 (en) * | 2008-02-14 | 2011-02-24 | Ezer Shitrit | Lamp with heat-responsive decoration |
| EP2337470A4 (en) * | 2008-09-26 | 2016-04-27 | Nike Innovate Cv | Systems and methods for stabilization of a phylon article |
| US8920206B1 (en) | 2012-02-08 | 2014-12-30 | Carolina Ip Llc | Interlocking swim noodles |
| US9211941B2 (en) | 2012-02-08 | 2015-12-15 | Douglas H. Bartow | Interlocking swim noodles |
| USD740385S1 (en) | 2013-08-11 | 2015-10-06 | Davis K. Bartow | Swim noodle |
| CN111356731A (en) | 2017-06-22 | 2020-06-30 | 意大利力索兰特绝热材料股份有限公司 | Coated closed cell foam pipe insulation and method of producing same |
Family Cites Families (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3331900A (en) * | 1963-10-08 | 1967-07-18 | Ind Vinyls Inc | Method of extruding a skin coated foamed plastic article |
| US3947169A (en) * | 1966-07-29 | 1976-03-30 | Allied Chemical Corporation | Apparatus for making rods or tubes having a filter |
| US3857914A (en) * | 1968-10-21 | 1974-12-31 | Asahi Chemical Ind | Method for extruding a foamed, molded article |
| US3654012A (en) * | 1970-02-04 | 1972-04-04 | Uniroyal Inc | Method of making a composite plastic article of manufacture |
| JPS491428Y1 (en) * | 1970-06-26 | 1974-01-14 | ||
| US3832260A (en) * | 1971-05-12 | 1974-08-27 | Cfs Corp | Method and apparatus for simultaneously applying to an extended cylindrical object a coating and a plastic film wrapping to retain the coating |
| GB1360303A (en) * | 1972-01-20 | 1974-07-17 | Ici Ltd | Injection moulding process |
| US3845184A (en) * | 1972-10-24 | 1974-10-29 | Phillips Petroleum Co | Extrusion of foamed polymer over diverging mandrel extension |
| US3874987A (en) * | 1974-03-13 | 1975-04-01 | Dow Chemical Co | Laminate of a moisture impervious polyethylene foam and a suspension chlorinated polyethylene sheet |
| GB1542585A (en) * | 1976-06-22 | 1979-03-21 | Sumitomo Chemical Co | Method of extrusion coating with polyolefin foam |
| US4322260A (en) * | 1979-04-04 | 1982-03-30 | Monsanto Company | Process for the continuous extrusion forming of a plastic double-walled foam-core conduit |
| US4518557A (en) * | 1981-05-18 | 1985-05-21 | James River-Norwalk, Inc. | Process for skin foam |
| US4600461A (en) * | 1983-09-12 | 1986-07-15 | Lof Plastics Inc. | Method of extruding a foamed thermoplastic core and extruding and integrally sealing a non-porous skin thereon |
| US4808450A (en) * | 1983-09-12 | 1989-02-28 | Sterling Engineered Products Inc. | Side body molding for attachment to a vehicle body |
| US4634615A (en) * | 1984-04-06 | 1987-01-06 | Versteegh Willem M | Heat recoverable coextruded articles |
| DE3541052A1 (en) * | 1985-11-19 | 1987-05-21 | Marquet & Cie Noel | FOAM PANELS AND BLOCKS FROM HOLLOW PROFILES, THEIR PRODUCTION AND THEIR USE AS INSULATING AND / OR DRAINAGE PANELS |
| US5286320A (en) * | 1991-11-18 | 1994-02-15 | Owens-Corning Fiberglas Technology Inc. | Method for making a pultruded panel |
| US5360048A (en) * | 1993-05-27 | 1994-11-01 | Nmc Of North America, Inc. | Surface coated, easily mountable cushioning member and method of manufacture |
| BR9304020A (en) * | 1993-10-15 | 1995-06-20 | Bernd Martin Reidl | Improvements in the structural composition of surfboards for chest |
| US6497919B1 (en) * | 1996-04-17 | 2002-12-24 | Industrial Thermo Polymers Limited | Two-part coated foam structure |
| US5773373A (en) * | 1996-06-18 | 1998-06-30 | Reef Industries, Inc. | Reinforced laminate with elastomeric tie layer |
| US5955013A (en) * | 1996-07-10 | 1999-09-21 | Owens Corning Fiberglas Technology, Inc. | Manufacture of foam-containing structures |
| US5904970A (en) * | 1997-06-13 | 1999-05-18 | Nomaco, Inc. | Integrally bonded, multilayer foamed product |
| US6183673B1 (en) * | 1998-04-24 | 2001-02-06 | Industrial Thermo Ploymers Limited | Method for forming extruded foam with surface coating |
-
1996
- 1996-04-17 US US08/633,943 patent/US6497919B1/en not_active Expired - Lifetime
-
1997
- 1997-04-17 CA CA002202953A patent/CA2202953C/en not_active Expired - Lifetime
-
1999
- 1999-12-07 US US09/456,995 patent/US6312630B1/en not_active Expired - Lifetime
-
2001
- 2001-02-09 US US09/779,533 patent/US6544448B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| US6497919B1 (en) | 2002-12-24 |
| US20020009583A1 (en) | 2002-01-24 |
| CA2202953A1 (en) | 1997-10-17 |
| US6312630B1 (en) | 2001-11-06 |
| US6544448B2 (en) | 2003-04-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2202953C (en) | Two-part coated foam structure | |
| US6054078A (en) | Integrally bonded, multilayer foamed product | |
| EP0001874B1 (en) | Method for producing shaped articles of polyolefins containing anisotropic filler using blow moulding techniques | |
| JPH028583B2 (en) | ||
| JPH0470988B2 (en) | ||
| JP2005519178A (en) | Polypropylene foam and foam core structure | |
| EP0731894B1 (en) | Pipe insulation with adhesive closure and its method of production | |
| KR100863058B1 (en) | Process for the production of an oriented plastic film | |
| CA2053779C (en) | Process for production of polypropylene sheets or films | |
| RU95112529A (en) | HAZER OF SMALL POWER AND METHOD OF ITS MANUFACTURE | |
| US4289727A (en) | Method for extrusion of tubular films | |
| CA2365417A1 (en) | Two-part coated foam structure | |
| EP0873485B1 (en) | Multi-lumen plastics tubing | |
| CA2268587C (en) | Apparatus for forming extruded foam with surface coating | |
| JP3248823B2 (en) | Plastic artificial wood, method of manufacturing plastic artificial wood, and coupled joiner used in the method | |
| CN112440460A (en) | Forming system and method for functional high polymer material in blown film processing | |
| US20030017285A1 (en) | Heat shrinkable film and jacket | |
| JPH06314523A (en) | Manufacture of multilayer sheath cable and device therefor | |
| JP3254493B2 (en) | Manufacturing method of imitation rush | |
| EP0163571A1 (en) | Method of producing light, rigid tubes from thermoplastic materials by multiple extrusion | |
| CN214324171U (en) | A molding system for blown film processing functional macromolecular material | |
| JP3254492B2 (en) | Manufacturing method of imitation rush | |
| JPH0289619A (en) | Manufacture of film | |
| DE4316863A1 (en) | Coextruded composite foam elements and process for their production | |
| JP3195968B2 (en) | Manufacturing method of imitation rush |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKEX | Expiry |
Effective date: 20170418 |