WO2000007839A1

WO2000007839A1 - Weatherseal having a contact layer with a particulate coating providing a reduced coefficient of friction

Info

Publication number: WO2000007839A1
Application number: PCT/US1999/014688
Authority: WO
Inventors: Krishnamachari Gopalan
Original assignee: Schlegel Corporation
Priority date: 1998-07-20
Filing date: 1999-06-28
Publication date: 2000-02-17
Also published as: WO2000007839A8; WO2000007839A9

Abstract

A weatherseal is disclosed having a substrate and a thermoplastic contact layer, wherein a multitude of surface particles are disposed on the surface of the contact layer. The weatherseal is formed by extruding the substrate and the contact layer to retain the surface of the contact layer in a partially molten state. The multitude of surface particles are then impacted with the molten surface of the contact layer to adhere to the contact layer thereby forming a coating.

Description

WEATHERSEAL HAVING A CONTACT LAYER WITH A PARTICULATE COATING PROVIDING A REDUCED COEFFICIENT OF FRICTION

Field of the Invention

The present invention relates to a seal for releasably contacting a panel, and more particularly, to a weatherseal for releasably contacting a glass panel in an automobile, wherein the weatherseal includes a contact surface with a reduced coefficient of friction for allowing the glass panel to be smoothly moved into and out of contact with the weatherseal, while reducing passage of water or air between a seated glass panel and the weatherseal. The present invention further relates to low friction surfaces for seals, and more particularly, to a weatherseal having a substrate and a contact layer, the contact layer including a multitude of particles bonded to the surface of the contact layer, wherein the particles may be thermoplastic or thermoset.

Background of the Invention

Many vehicles employ windows formed of glass panels, wherein the window is moveable relative to a portion of the vehicle. A common construction includes the use of a glass panel in a door, wherein the door and the glass panel move relative to the remainder of the vehicle, and the glass panel moves relative to the door. In this construction, the glass panel is frequently moved between an open position and closed position with respect to the door and/or a portion of the vehicle frame. Increased business transactions such as restaurant, banking and pharmacy services are now regularly offered in a drive-through format. These transactions require the repeated release and engagement of the glass panel and vehicle. The repeated opening and closing of the glass panel places significant stress on the seal between the glass panel and the vehicle.

Traditionally, a weather strip is employed at the interface between the glass panel and the vehicle door and/or the vehicle. The interface between the weather strip and the glass panel must be sufficient to substantially preclude the penetration of water and air along the periphery of the glass panel, while still permitting ready engagement and disengagement of the glass panel without requiring significant force. Conventional sealing structures include a soft synthetic resin or synthetic rubber.

However, such weather strips do not provide for the ready opening and closing of the glass panel relative to the seal. Further this structure often presents difficulty in securing of the door relative to the vehicle. Further, a large force is loaded on the window glass thus resisting opening or closing of the window glass.

Prior weather strips often employed a flock such as polyester on the area in which the weatherseal contacts the glass panel. However, the flocking process is very complicated. The complex manufacturing process adds to the cost of the weather strip. Further, the flocking is relatively easily removed or worn away. As the flock is worn from the weatherseal, the loading force substantially increases.

Therefore, the need exists for a weatherseal that has reduced force requirements for moving a glass panel into and out of engagement with the weather strip. The need also exists for a weatherseal having enhanced wear capabilities. A need also exists for a method of forming a low friction weatherseal. Summary of the Invention

The present invention provides a weatherseal having a contact layer located on selected portions of a substrate, wherein a multitude of surface particles are adhered to the surface of the contact layer to define a reduced area of contact. The weatherseal reduces migration of the environment between the seal and the panel, as well as reduce the generation of noise upon relative motion between the weatherseal and the panel.

The substrate may be any of a variety of materials such as thermoplastic, thermoset or TPEs in a variety of profiles. The contact layer is a thermoplastic having a surface coating of surface particles bonded to a thermoplastic.

In a preferred construction, the substrate is an extruded profile, wherein the thermoplastic of the contact layer is disposed on selected portions of the substrate. The thermoplastic of the contact layer is brought to a sufficient temperature so that a multitude of surface particles can be impacted with the thermoplastic and sufficiently bond to the thermoplastic to preclude unintended separation. Brief Description Of The Drawings

Figure 1 is a perspective view of a first weatherseal configuration.

Figure 2 is a perspective view of a second weatherseal configuration.

Figure 3 is a perspective view of a third weatherseal configuration.

Figure 4 is an enlarged view of the surface of the contact layer of the weatherseal.

Figure 5 is a partial cross-sectional view of the surface of the contact layer of Figure 4.

Figure 6 is a an enlarged to plan view of the contact layer of Figure 4.

Figure 7 is a chart of the relationship of dynamic coefficient of friction (C.O.F.) for various materials in the contact layer.

Figure 8 is a chart of the relationship of static coefficient of friction (C.O.F.) for various material in the contact layer.

Detailed Description of the Preferred Embodiments

The present invention includes a weatherseal 20 having a substrate 40 and a contact layer 60. The contact layer 60 includes a multitude of surface particles 62, selected to provide a reduced coefficient of friction with a panel. It is understood the panel may be any of a variety of materials such as, but not limited to, glass, plastics, composites or metal, which may be coated, painted, surface treated or bare. Therefore, the panel may include glass such as windows and metal or composites such as vehicle body parts.

The substrate 40 is a base upon which the contact layer 60 is located. The substrate 40 may be formed of a variety of materials such as thermoplastics, thermosetting materials and thermoplastic elastomers (TPEs). A preferred material for the substrate 40 is olefinic TPE. The substrate 40 may be any of a variety of configurations such as "U", "C", folded "J" or planar. The substrate may also include a reinforcing member 42 such as a metal carrier, wire or thermoplastic. Thus, the substrate 40 may having differing rigidities in different sections. In addition, the substrate 40 may have a varying thickness to provide a desired resiliency at specific locations along the weatherseal 20.

The contact layer 60 may also be formed of a variety of materials including thermoplastics as well as thermoplastic elastomers. A preferred material is polyethylene or polypropylene with a high melt flow index. The contact layer 60 is located on at least those portions of the substrate 40 that engage the panel. The thermoplastic material of the contact layer 60 is selected to bond to the substrate 40 and substantially preclude unintended separation. It is preferable that the material of the substrate 40 and the contact layer 60 be selected to bond without the need for supplemental adhesives of bonding agents. However, it is understood such supplemental adhesives may be employed.

A multitude of surface particles 64 are bonded to an exposed surface of the contact layer 60. The surface particles 64 may be any of a variety of materials that do not degrade or mar the panel upon contact with the panel. Preferably, the surface particles do not exhibit a melting temperature, but rather degrade or disintegrate without melting upon the application of sufficient heat. That is, the surface particles 64 are not meltable and upon the applications of heat initially retain their solid state. Upon a sufficient amount of heat, the surface particles irreversibly degrade, such that upon cooling do not return to their original composition. The surface particles 64 may be formed of PTFE, molybdenum disulfide ceramic radiation cross linked ultra high molecular weight polyethylene. The surface particles 64 are selected to have sufficient strength such that upon operable loading, the particles do not fracture or break. The surface particles 64 are selected to form a bond upon engaging the contact layer. While supplemental adhesives may be employed, it is preferable to employ complementary surface particles 64 and thermoplastic material of the contact layer to form a bond therebetween without requiring supplemental adhesives. The materials are selected to provide a chemical bond between the surface particles.

The surface particles 64 may have a size ranging from approximately 10 microns to approximately 120 microns.

The surface of the contact layer 60 is thus defined by a multitude of projections. The projections generally define the contact area between the contact layer weatherseal and the panel. The projections have a density of approximately 50 to approximately 300 projections per square inch. The projections extend from an adjacent portion of the surface of the contact layer by a distance of approximately 5 microns to approximately 100 microns. The surface particles are generally contacting the material of the contact layer 60 over a portion of the respective surface particles. That is, a portion of the surface particle 64 will be covered with the material of the contact layer 60 and a remaining portion of the surface particle will be exposed. The substrate 40. the contact layer 60 and the surface particles 64 are selected such that upon a compressive force against the contact surface, the surface particles are not substantially displaced into the contact layer or the underlying substrate. That is, the surface particles 64 maintain the reduced area of contact between the weatherseal 20 and the panel.

Thus, different sections of the contact layer 60 may have different surface particles 64. It is also understood that a combination of surface particles 64 may be employed. For example, different types of non melting materials may be combined and bonded to the contact layer. Similarly, different size surface particles 64 may be employed. Again, the different materials may be employed in a mixture of different sizes, or separate sections of the weatherseal may have different size surface particles.

It has also been found that the present weatherseal 20 reduces noise generation resulting from relative motion between the panel and the weatherseal. The noise reduction occurs for dry as well as wet conditions.

Method of Manufacture

Generally, the weatherseal 20 is constructed by extruding the substrate 40, locating the contact layer 60 on the substrate, rendering the contact layer to an at least partially molten state and impacting the surface particles 64 with the molten portion of the contact layer 60 to adhere the surface particles to the contact layer.

In a first method of construction, the present weatherseal 20 is formed by extruding a first and a second thermoplastic elastomer, wherein the first thermoplastic elastomer forms the substrate 40 and the second thermoplastic elastomer forms the contact layer 60. If a reinforcing member 42 is to be incorporated into the substrate 40, the reinforcing member is generally coextruded with the first thermoplastic elastomer.

During formation, the extrusion temperature of the second thermoplastic elastomer forming the contact layer 60 is such that upon passing from the die, the material remains in an at least semi-molten state. As the substrate 40 and contact layer 60 exit the die, the surface particles 64 are deposited onto the second thermoplastic elastomer of the contact layer 60. Preferably, the surface particles 64 become sufficiently embedded with the second thermoplastic elastomer to bond to the material. Alternatively, the substrate 40 and the thermoplastic of the contact layer 60 may be coextruded, cooled and stored. At a later, time the temperature of the thermoplastic of the contact layer 60 is raised to at least a semi-molten state for receiving the surface particles 64.

The surface particles 64 embedded in the contact layer 60 are in a powder form. It is contemplated the surface particles 64 may be introduced into the contact layer 60 by gravity assisted deposition. Alternatively, the particles 64 may be introduced under an increased velocity by an ejector or spreader. Further, it is contemplated the surface particles 64 may be pressed to the contact layer 60 by a roller.

Depending upon the velocity of the impacting surface particles 64, the viscosity of the molten contact layer 60 and the selected materials of the particles and the contact layer, the surface particles may be entirely encompassed within the thermoplastic material of the contact layer and thus coated by the contact layer. It is also understood the surface particles 64 may be partially coated by the contact layer 60 and thus exhibit an exposed surface of the material. Thus, embedding includes bonding of the surface particles 64 to the thermoplastic, wherein the particles are partially or completely covered by the thermoplastic.

As the surface particles 64 are adjacent the surface of the contact layer 60, the contact layer has a surface defined by a multitude of projections. The projections may be a combination of the material of the contact layer surrounding the particle or the material of a surface particle 64 that is bound to the contact layer having an exposed surface.

While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made without departing from the scope of the invention. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope and spirit of the appended claims.

Claims

In the Claims

1. A method of forming a weatherseal, comprising:

(a) extruding a substrate and a contact layer, the contact layer being in an at least partially fluid phase; and

(b) bonding a multitude of surface particles with the contact layer after extrusion.

2. The method of Claim 1, further comprising bonding ultra high molecular weight polyethylene surface particles to the contact layer.

3. The method of Claim 2, further comprising bonding cross linked ultra high molecular weight polyethylene surface particles to the contact layer.

4. The method of Claim 3, further comprising bonding radiation cross linked ultra high molecular weight polyethylene surface particles to the contact layer.

5. The method of Claim 1, wherein the surface particles impact the contact layer with sufficient velocity to be embedded in the contact layer.

6. The method of Claim 1, further comprising embedding the surface particles into the contact layer to operably retain the surface particles relative to the substrate.

7. The method of Claim 1, further comprising coextruding the substrate and the contact layer.

8. The method of Claim 1, further comprising subsequently extruding the contact layer onto the substrate.

9. The method of Claim 1 , further comprising employing one of the╧Çnoplastic and thermoset particles as the surface particles.

10. A weatherseal having a reduced coefficient of friction, comprising:

(a) a substrate;

(b) a contact layer disposed on a portion of the substrate: and

(c) a multitude of surface particles adhered to a surface of the contact layer to form projections.

1 1. The weatherseal of Claim 10, wherein the surface particles are ultra high molecular weight polyethylene.

12. The weatherseal of Claim 10, wherein the surface particles are cross linked.

13. The seal of Claim 10. wherein the surface particles are radiation cross linked ultra high molecular weight polyethylene.

14. The seal of Claim 10. wherein the surface particles have a size between approximately 10 microns and approximately 120 microns.

15. The seal of Claim 10. wherein the surface particles are the projections.

16. A weatherseal, comprising:

(a) a substrate;

(b) a thermoplastic contact layer on a portion of the substrate; and

(c) a surface coating of particles on a surface of the contact layer.

17. The weatherseal of Claim 16, wherein the substrate includes one of a thermoplastic and a thermoset material.

18. The weatherseal of Claim 16, further comprising a reinforcing member in the substrate.

19. The weatherseal of Claim 16, wherein the surface particles are one of a thermoplastic and a thermoset material.

20. A weatherseal, comprising:

(a) a substrate; and

(b) a thermoplastic contact layer on at least a portion of the substrate, the contact layer having a multitude of projections formed from a surface coating of particles bonded to the thermoplastic.

21. The weatherseal of Claim 20, wherein the substrate includes one of a thermoplastic and a thermoset.

22. The weatherseal of Claim 20, wherein the surface particles are one of a thermoplastic and a thermoset.

23. A weatherseal for releasably contacting a panel, comprising:

(a) a substrate;

(b) a thermoplastic contact layer on a portion of the substrate; and

(c) a sufficient multitude of surface particles on the contact layer to substantially preclude noise generation upon relative motion between the weatherseal and the panel.

24. The weatherseal of Claim 23 , wherein the surface particles are one of a thermoplastic and a thermoset.