Patent Description:
Weather seals or weather-strips are commonly attached to the edges of doors and windows to decrease or prevent air from permeating between the interior and exterior of the door or window. Weather seals are also used to seal between the moving components of a window and door. Most typically weather seals are composed of thermoplastic elastomers or EPDM rubber, wrapped urethane foam or other flexible thermoset materials. These materials provide flexibility, resiliency, durability, and generally have low coefficients of friction and provide a consistent low closing force. Minimizing the loss of functional height of the weather seal over the life of the window or door is very important. Examples of weather seals are known e.g. from <CIT> and <CIT>.

More advanced weather seals feature multiple bulbs and sealing flaps that extend the reach of a bulb seal. Some advanced or higher performance weatherseals have a solid foam center made from urethane foam or a TPE water blown foam. In some cases a hollow foam may be used to reduce closing forces. The materials and processing methods used to make foam filled seals are complex, expensive and require multiple steps. Urethane seals are not recyclable and utilize a two-part chemistry process that requires special handling methods. The two advanced weathers seals described above will use at least three different materials requiring three extruders and if they add a slip coating to reduce friction, a fourth extruder is required. This results in an expensive process that takes up a considerable amount of space. These processes also require highly skilled workers due to the complexity of the processes used.

Accordingly, there is a need in the art for a more cost-effective solution that produces a resilient foamed bulb seal with insertion barbs that is recyclable and has a low closing force and a very low loss of functional height over time. This cost effective and environmental friendly solution would use two, or at most three conventional extruders in a single step process if a slip coating is required.

The present invention is directed to a micro-cellular foam weather seal as defined in claim <NUM> and to a method as defined in claim <NUM> for manufacturing the seal.

According to an aspect is a weather seal for use on a weather permeable barrier separating the indoor from the outdoor, comprising: an elongated, compressible micro-cellular foam bulb adapted for connection to the barrier; and an elongated, compressible micro-cellular foam element extending along the length of the foam bulb, wherein the foam element is spaced from the barrier.

According to an embodiment, the weather seal further comprises a silicone slip agent incorporated therein.

The weather seal further comprises a polypropylene member attached to and extending the length of the foam bulb and to which the foam element is attached.

According to an embodiment, the polypropylene member comprises an elongated spine having opposing surfaces and the foam element comprises at least one barb extending off of each surface of the spine.

According to an embodiment, the weather seal further comprises a pair of sealing flaps that extend diagonally upward from the top of bulb, opposite the spine.

According to an embodiment not covered by the invention, the foam bulb is of a first predetermined diameter and the foam element comprises a bulb-shape and is of a second diameter smaller than the first diameter.

According to an embodiment not covered by the invention, the foam bulb is tear-drop shaped and or a predetermined length and the foam element is of a bulb-shape having a diameter that is smaller in dimension than the predetermined length.

According to an embodiment, the bulb has hardness in the range of <NUM> to <NUM> durometer on a shore A scale and the foam element has a hardness in the range of <NUM> to <NUM> durometer on a shore A scale.

According to an aspect is a method for manufacturing a micro-cellular foam weather seal for use on a weather permeable barrier separating the indoor from the outdoor and having an elongated, compressible micro-cellular foam bulb adapted for connection to the barrier and an elongated, compressible micro-cellular foam element extending along the length of the foam bulb, wherein the foam element is spaced from the barrier, wherein the weather seal further comprises a polypropylene member attached to and extending the length of the foam bulb and to which the foam element is attached, the method comprising the steps of: delivering the micro-cellular foam material from a storage cell to a weigh scale blender and then to a drier; delivering the micro-cellular foam material from the drier to a main extruder; delivering a polypropylene material from a storage cell to a first co-extruder; pulling the micro-cellular foam material and the polypropylene material from through the main extruder and first co-extruder, respectively, and into a die; forming the weather seal in the die; pulling the weather seal from the die and into a sizer plate; pulling the weather seal from the sizer plate into a cooling tank; blowing off excess water from the weather seal after it passes out of the cooling tank; and winding the weather seal on a reel.

According to an embodiment, the method further comprises the step of providing a second co-extruder and delivering a slip agent material into the second co-extruder.

According to an embodiment, the method further comprises the step of injecting the slip agent material from the second c-extruder into the die, whereby the slip agent material will coat the weather strip as it comes out of the die.

According to an embodiment, the method further comprises the step of optically inspecting the weather strip as it comes out of the cooling tank.

According to an embodiment, the method further comprises the step of maintaining the water in the cooling tank at a predetermined temperature.

These and other aspects of the invention will be apparent from the embodiments described below.

The present invention will be more fully understood and appreciated by reading the following Detailed Description in conjunction with the accompanying drawings, in which:.

The present disclosure describes a micro-cellular thermoplastic elastomer foam weather seal. The material used for the weather seal may be any of: TPE - Thermoplastic Elastomers, TPV- Thermoplastic Vulcanizates, or TPO- Thermo plastic Olefins.

Referring to <FIG>, in one embodiment, is a micro-cellular foam weather seal <NUM>, generally comprising an elongated, bulb-like body <NUM>, and an elongated barb element <NUM> that extends along the length of body <NUM>. Fin element <NUM> comprises a fin/spine <NUM> that has opposing, planar surfaces, and a series of barbs <NUM> that extend outwardly and at an angle towards the body <NUM> from each planar surface of fin/spine <NUM>. Barbs <NUM> are shorter in width than the height of fin/spine <NUM> and are positioned in parallel, laterally spaced relation to one another along the height of the fin/spine <NUM>.

Barbs <NUM> and body <NUM> are composed of a thermoplastic elastomer with a chemical foaming agent (to produce a microcellular foam), while fin/spine <NUM> is composed of polypropylene. The thermoplastic elastomer has a Shore A hardness of <NUM> durometer to <NUM> durometer, and more preferably, <NUM> to <NUM> and the chemical foaming agent reduces the density by <NUM>% - <NUM>%. Body <NUM> has a preferable thickness of <NUM>" to <NUM>".

Because of the microcellular foam composition of weather seal <NUM>, it has the flexibility and resiliency to wrap around corners and maintain a pliable <NUM>-degree angle, as shown in <FIG>. In addition, this pliability permits a single weather strip <NUM> to be used on, for example, the bottom and side edges of a barrier between the indoors and outdoors, such as a door or window <NUM>, as shown in <FIG>, thus eliminating seams between strips of weather seal as would be necessary but for the pliability provided by seal <NUM>.

In addition to the advantages of enhanced pliability, the microcellular foam composition lowers the cost and reduces the weight of the seal. Furthermore, the microcellular foam lowers the closing forces needed to be exerted by the user, thereby reducing pressure on the door/window hardware (closing force is no more than <NUM> lbs. per foot in most common designs); this is particularly important for installations that are focused on compliance with the Americans with Disabilities Act. Also, the compression set resistance is approximately <NUM>% or lower.

The foaming agent used to form seal <NUM> is also capable of receiving a silicone slip agent <NUM> that will reduce the coefficient of friction by at least <NUM>%. This will further enhance the seal's advantages beyond its low closing force and light weight. Coloring agents could also be added for aesthetics. The desired lower coefficient of friction can be achieved by adding the slip agent into the polymer mix or it can be achieved by selectively coextruding a thin layer of the slip material on the surface of the weatherseal in the area that will be in contact with the mating surface.

To manufacture seal <NUM>, a co-extrusion of two materials, both of which are foamed, is employed. Barbs <NUM> are foamed which simplifies the tooling design, resulting in two extruders being needed. An extended mandrel is used to improve the melt strength of the material as the foaming occurs when the material exits the die face and hits atmospheric pressure. The extended mandrel provides enhanced strength until the material gets closer to the water-cooling tank.

With reference to <FIG>, a flow chart that illustrates the manufacturing process employed is provided. For purposes of manufacturing a foam bulb <NUM>, wherein the part will be printed <NUM>, a set up sheet <NUM> is configured with the die tooling, main extruder heat settings, and material recipe listed (see <FIG> and <FIG> for a sample set up data sheet). This set up sheet <NUM> is used to prepare the manufacturing line, step <NUM>. A microcontroller determines whether the line is set with the correct die assembly in step <NUM>. If not, the set up sheet <NUM> is referenced in step <NUM> such that the correct die assembly is set. Once the correct die assembly is set in step <NUM> or confirmed in step <NUM>, the microcontroller verifies whether the material recipe is correctly programmed in the line in step <NUM>. If not, the program recipe is referenced in step <NUM> from set up sheet <NUM>. Once the recipe is verified, the microcontroller verifies whether the extruder heat setting are correct in step <NUM>. If not, the heat settings of the extruder are referenced from set up sheet <NUM> and corrected in step <NUM>. Once verified, the manufacturing line begins to string up the foam bulb in step <NUM>, and in step <NUM> the microcontroller instructs the foaming procedure to execute pursuant to the set up sheet <NUM>. The microcontroller then runs the line for <NUM> minutes in step <NUM> to allow the pressure of the material to stabilize. A counter <NUM> confirms when the <NUM> minute stabilization period has run. Once run and the manufacture of a foam bulb is executed the part is quality checked in step <NUM> via an optical inspection device, and if it does not pass the quality test, the speed of the extruders is manipulated in step <NUM> until the quality is acceptable. Once the quality is acceptable, the quality foam bulb is taken off the assembly line in step <NUM> (and reeled or cut to length and packaged).

With reference to <FIG>, a block diagram of the manufacturing line is provided. The line includes a material TPV/CFA, for example) mixing and drying vessel <NUM> which conveys the mixed/dried material to a material distribution vessel <NUM> that will distribute the materials to a main extruder <NUM> via a hopper <NUM>. Polypropylene distribution vessel <NUM> is set up in parallel with vessel <NUM>, and distributes the PP material to a first co-extruder <NUM>. A slip material vessel <NUM> also is st up in parallel and distributes slip material to a second co-extruder <NUM>. Main extruder <NUM>, first extruder <NUM> and second co-extruder <NUM> are positioned to extrude the materials into a three piece extrusion profile die <NUM> that includes three material exits (one for the foamed PV material, one for the PP material, and one for the low friction slip material). Once exiting the die <NUM>, the extruded weather-strip then enters a sizer plate <NUM> that is at the leading end of a cooling water tank <NUM> that is filled with <NUM> degree F water. A water chiller <NUM> maintains the water at the chilled temperature. As the weather-strips is pulled through the water tank <NUM> it then passes a blower <NUM> that blows off excess water, before passing through the puller/cutter <NUM> that pulls the weather-strip though the entire line and cuts it into desired lengths or the product passes through cutter device to be wound onto a reel by a winder <NUM>.

<FIG> shows a more detailed view of some of the equipment. Mixing and drying vessel <NUM> includes a TPE holding cell <NUM> and a PP holding cell <NUM>. The TPE material is delivered to a weigh scale blender <NUM> where the CFA and TPV materials are mixed and then passed into a drier <NUM>.

<FIG> show more details of die <NUM> used to form the weather-strip. Die <NUM> comprises three plates: a back plate <NUM>, a compression plate <NUM>, and a front plate <NUM>. Material enters back plate <NUM> from the extruders <NUM>, <NUM>, and <NUM> and exits die <NUM> through front plate <NUM>. The back plate <NUM> includes the main extruder input <NUM> where the micro-cellular foam material is introduced into die <NUM>. A co-extrusion input is provided for introduction of the PP material into die <NUM> (and a separate input can be provided for slip agent entrance). A splitter separates the main extruder materials into two sections - one for the bulb and one for the barbs. Back plate's back face matches the face of the extruder's adaptor die which is the first face of the profile die assembly that material is introduced.

A mandrel <NUM> is inserted into compression plate supplies air into the die <NUM> which is critical in tolerancing and processing. The mandrel <NUM> extends about a half an inch from the front face of the die <NUM>. This extra length aids in improving melt strength upon exiting the die prior to cooling in the water tank.

After exiting compression plate <NUM>, the material hits the front face of the front plate <NUM>. Upon exiting the front face of the front plate the various separate channels derived from the two materials merging together connect as one in the final opening.

Claim 1:
A weather seal (<NUM>) for use on a weather permeable barrier (<NUM>) separating the indoor from the outdoor, comprising:
a. an elongated, compressible micro-cellular foam bulb (<NUM>) adapted for connection to the barrier; and
b. an elongated, compressible micro-cellular foam element (<NUM>) extending along the length of the foam bulb (<NUM>), wherein in use the foam element (<NUM>) is spaced from the barrier; characterized by
c. a polypropylene member (<NUM>) attached to and extending the length of the foam bulb (<NUM>) and to which the foam element (<NUM>) is attached.