The current industry practice in the field of window profile reinforcing inserts is to insert a separate metal shape inside the hollow polyvinylchloride (PVC extrusion) during the assembly process of the window. Specifically, a window profile is first extruded to include a hollow area and then a desired metal insert is assembled into the hollow area. One disadvantage of the current practice is that separate profile extrusion and insert assembly requires multiple manufacturing steps.
In embodiment of the present invention, the need for additional manufacturing steps is avoided by providing simultaneous and continuous-line insertion of metal inserts, including aluminum inserts, into a window profile during the extrusion process.
Embodiments of the invention include inserting aluminum reinforcing strips into vinyl window profiles, including PVC window profiles, with use of heat activated adhesive. Strips are inserted and fed through desired slots in an extrusion die during the PVC window profile extrusion process and are integrated in the window profile at the desired locations where the slots are present.
An advantage of embodiments of the invention includes increasing the strength of a PVC window extrusion as metal, such as aluminum , is stronger than PVC alone or fiberglass reinforced vinyl profiles.
Another advantage of embodiments of the invention is avoiding additional manufacturing steps as convention window manufacturer currently insert a separate aluminum extrusion inside a PVC extrusion that is separately created.
Another advantage of embodiments of the invention is that aluminum, particularly aluminum pre-coated with a heat-activated adhesive in some embodiments, inserted during the PVC profile extrusion process helps control thermal expansion/contraction of PVC.
Other advantages of embodiments of the invention include that multiple inserts, such as aluminum strips, can be inserted simultaneously at several desired locations in a profile to provide specific reinforcement characteristics to the profile while avoiding multiple manufacturing steps and assembly that would be required with traditional post-extrusion insertion methods.
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In certain embodiments, aluminum strip inserts 20 are pre-coated on some or all surfaces with a heat-activated adhesive. Such adhesives are known from use in the automobile industry. However, in the automobile industry the adhesive is used with stiffening elements where the metal is used as the profile, as opposed to the invention's window profile preferably being composed of rigid PVC, and softer, flexible vinyl or plastic material (not rigid PVC) being extruded to bond with the metal profile to make items such as window and door seals.
Advantageously in embodiments of the invention, a heat-activated adhesive pre-applied to the metal insert 20, such as aluminum strips, provides a continuous bond along the entire surface of the metal insert 20. The adhesive used in the extrusion process of embodiments of the invention creates a bond between the PVC of the profile 10 and metal insert 20 that avoids the occurrence of shearing.
In some embodiments infrared (IR) heating can be applied to some or all of the surface of an aluminum strip insert 20 pre-coated with adhesive prior to extruding the PVC. Preferably heat is applied just at the surface to activate the adhesive but not heat the whole aluminum throughout the insert 20 and have negative effect on the rigid PVC profile (such as by requiring to cool the PVC profile since whole aluminum would otherwise be hot).
In addition to or as an alternative to IR surface heating (to just heat a surface of the metal), heat may be applied in a broad range of from 24 degrees Celsius to 190 degrees Celsius to heat metal inserts 20, such as aluminum strips, and still get a bonding effect of the metal insert 20 to the cellular and/or non-cellular rigid PVC of the profile 10. In the prior art, such as automotive industry techniques with flexible vinyl/plastic and pre-treated metal profiles that may include adhesive, it is typically recommended that heating of the metal profile is from 160-190 degrees Celsius. Our discovery of lower temperature heating of aluminum inserts 20 to co-extrude with rigid PVC, as well as IR surface-focused heating, are both advantages of the invention's different use of metal elements as stiffening elements within rigid PVC, and particularly in window profiles, in comparison to the prior art techniques intended for different purposes.
In some embodiments of the invention, metal inserts 20 are aluminum elements that may be flat. In some embodiments metal inserts 20 are flat and in the form of strips that may be provided on coils and then fed through die 30 during the extrusion process. In other embodiments metal inserts 20 may be shaped. In further embodiments flat and shaped aluminum inserts 20 may both be used in the same extrusion.
In embodiments, the die temperature of the PVC for co-extrusion with the metal insert 20 is typically 170-180 degrees Celsius (with melt temp of PVC of 170-190 degrees Celsius).
In embodiments, the line speed for the extrusion process, including the feeding of inserts through an extrusion die, may be at least 40 inch/min . In some embodiments the line speed may be from about 40 inch/min and up to about 120 inch/min and even higher. Preferably, about 40 inch/min is a low-end parameter since running slower would likely not provide competitive manufacturing speed.
In some embodiments, where the insert 20 is a flat metal aluminum insert, although not limited to flat or aluminum in other embodiments, may be from about 0.012-0.120 inches thick. In preferred embodiments a flat insert 20 utilized may be about 0.032 inches thick. In other embodiments a considerably thicker insert 20 to provide further stiffening may be about 0.064 inches thick. It will be appreciated that thickness of the insert 20 may be adjusted to the particular application of the co-extruded profile and desired function of the insert 20.
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While the invention has been described with reference to exemplary structures and methods in embodiments, the invention is not intended to be limited thereto, but to extend to modifications and improvements within the scope of equivalence of such claims to the invention.
The present application claims priority to U.S. Provisional Application No. 62/015,039 filed Jun. 20, 2014, the contents of which are incorporated herein by reference in their entirety.
Number | Date | Country | |
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62015039 | Jun 2014 | US |