Fire Resistant Corner Guard

Field of the Invention

The field relates to furniture and, among other things, relates to a fire retardant corner guard for mattresses, foundations, and bedding assemblies. In particular, it relates to the application of fire retardant corner guards for bedding assemblies and the manufacture thereof.

Background of the Invention

Today, the mattress industry is taking steps to produce mattress that have reduced susceptibility to an open flame. The goal is to provide mattresses and beds that will resist combustion when exposed to an open flame and the conditions that can occur when a room or home begins to burn.

To slow the rate of burning of a mattress, engineers and chemists have examined the mattress and foundation structure to identify how an open flame can effect these structures and to determine techniques for retarding the spread of a fire. These engineers and chemists have modeled the padding and ticking of the mattress and foundation as a fuel source, and have developed techniques for retarding the combustion of- these materials. To this end, mattresses have been engineered to contain two key fire retardant systems. The first is a fire barrier within a mattress which sequesters the highly flammable materials that comprise the core cushioning of the mattress. The second are chemical/polymeric fire retardant additives that can function to reduce the fiammability of the ticking and other layers external to the fire barrier.

These existing fire retardant systems in mattresses have greatly reduced the burn time of the mattress and improved the survivability of mattress fires. However, studies of mattress exposed for long periods of time to an open flame have shown that mattresses even treated with fire resistant compounds, will, over time begin to combust, In may cases the combustion is slowed by the addition of halogenated compounds that starve the flame of

oxygen, But under certain circumstances and has been found that from time to time the burning mattress or foundation will flare up, at least for a brief period of time. This of course is undesirable.

Thus, there remains a need for improvements in making mattresses and foundations even more resistant to open flames and combustion., however, areas for improvement remain.

Summary of the Invention

The invention provides corner guards suitable for use with a bedding assembly and providing a degree of flame resistance (FR). The corner guards described herein may contain FR polymeric reagents, flammable polymeric reagents combined with one or more FR agent or have an FR coating. Additionally, the corner guards of the invention have effective FR properties while substantially maintaining the mechanical properties that allow the corner guard to support and protect the edges of upholstered furniture, such as a foundation or sofa. The corner guards described herein arise, at least in part, from the realization that flare ups occurring during the test about the combustion of an FR foundation, result from high burn temperatures causing the corner guard to melt and the subsequently combustion of the melted polymeric material.

More particularly, a corner guard for a bedding assembly may comprise a rigid body having a side wall that is curved about a longitudinal axis and configured to be positioned at a corner of a bedding assembly, wherein the rigid body includes a fire retardant material.

Optionally at least a portion of the side wall includes the fire retardant material, and the fire retardant material may be mixed within or coated over the rigid body or affixed to the sidewall. The corner guard may be internal or external and the rigid body may be configured for positioning on a base of a box spring or the rigid body may be configured for positioning between a mattress foundation and a frame supporting the mattress foundation. External corner guards may have optional decorative elements. The rigid body typically includes a top end, a bottom end and the corner guard further comprises a locator flange

adjacent to the bottom end of the rigid body. Optionally, the rigid body will include a top end, a bottom end and the corner guard further comprises a limit flange adjacent to the top end of the rigid body. On optional strengthening rib may be added thatis formed in the side wall and extending in the longitudinal direction, and there may be at least one strengthening rib that extends perpendicularly from adjacent a top end of the rigid body to adjacent a bottom end of the rigid body.

The side wall may have a convex outer surface and the rigid body may be bent such that a portion of the side wall is perpendicular to another portion of the side wall along the longitudinal axis. The thickness of the rigid body across the side wall is typically substantially uniform, and the thickness may be selected as a function of the flame/fire resistance that the is desired. Similarly, the amount of FR material intermixed with or coated over the rigid body may vary depending upon the flame/fire resistance sought. The rigid body may a material selected from the group consisting of a plastic material, paper, corrugated paper, wood, Masonite, fiberglass, metal, and polyethylene, polypropylene or acrylovnitrate-butadiene-styrene. The fire retardant material has material properties selected such that the corner guard meets the California Bureau of Home Furnishings Technical Bulletin 129 Flammability Test Procedure, and may include a halocarbon, such as at least one of polybrominated diphenyl ether and polychlorinated biphenyl ether. Optionally, the rigid body includes substantially impact-resistant materials.

In alternative embodiments and aspects, the systems described herein include a bedding assembly having a mattress foundation with a bottom surface, an upper support surface, and a plurality of side surfaces extending between the bottom surface and the upper support surface. Two of the side surfaces intersect to form an exterior corner, and a frame supports the mattress foundation. A fire retardant corner guard is positioned along the exterior corner and attached to the mattress foundation to cover at least a portion of the exterior corner.

In a further aspect, the invention provides a method of manufacturing a corner guard for a bed assembly, comprising providing a rigid body having a side wall that is curved about a longitudinal axis and configured to be positioned at a corner of a bedding assembly,

and applying at least one layer of fire retardant material across a portion of the side wall. In another practice, the method of manufacturing a corner guard for a bed assembly, includes providing a corner guard mold, introducing a molten rigid body material into the corner guard mold, combining a fire retardant material with the molten rigid body material, and allowing the molten rigid body material to set, thereby forming a rigid body shaped as the corner guard mold and having fire retarding materials.

Brief Description of the Drawings

The foregoing and other objects and advantages of the invention will be appreciated more fully from the following further description thereof, with reference to the accompanying drawings wherein;

FIG. 1 is a perspective view of a corner of a bedding assembly, according to an illustrative embodiment of the invention.

FIG. 2A is a perspective view of an exemplary FR corner guard used with bedding assembly of FIG. 1.

FIGS. 2B and 2C depict cross-section views of the FR corner guard of FIG. 2 A, according to various illustrative embodiments of the invention.

FIG. 3 is an inside perspective view of a bed box spring, according to an illustrative embodiment of the invention.

FIG. 4A is a perspective view of an exemplary FR corner guard used with the box spring of FIG. 3.

FIGS. 4B and 4C depict cross-section views of the FR comer guard of FIG. 4A, according to various illustrative embodiments of the invention.

FIG. 5 depicts an exemplary injection molding system for manufacturing an FR corner guard.

Detailed Description of the Illustrative Embodiments

To provide an overall understanding of the invention, certain illustrative embodiments will now be described, including a corner guard suitable for use in a mattress foundation and methods for making such a corner guard. As set out below the invention provides, among other things, fire resistant corner guards and furniture with fire resistant corner guards that may be internal corner guards or external corner guards. However, the embodiments set out below are merely for the purpose of illustration and it will be understood by one of ordinary skill in the art that the systems and methods described herein may be adapted and modified for other suitable applications and that such other additions and modifications will not depart from the scope hereof.

In one aspect, the devices described herein provide corner guards suitable for use with a mattress foundation and providing a degree of flame resistance. The corner guards may contain FR polymeric reagents, flammable polymeric reagents combined with one or more FR agent or have an FR coating. Additionally, the corner guards of the invention have effective FR properties while substantially maintaining the mechanical properties that allow the corner guard to support and protect the edges of upholstered furniture, such as a foundation or sofa. The comer guards described herein arise, at least in part, from the realization that flare ups occurring during the test about the combustion of an FR foundation, result from high burn temperatures causing the corner guard to melt and the subsequently combustion of the melted polymeric material.

FIG. 1 is a perspective view of a corner of a bedding assembly 100, according to an illustrative embodiment of the invention. The bedding assembly 100 includes a mattress 106, and a mattress foundation 104 and a bedding support structure such as a bed frame 108. The mattress foundation 104 may be configured and positioned to support mattress 106 above the bed frame 108. the bedding assembly 100 also includes a flame/fire resistant (FR) or flame/fire retardant (FR) comer guard 102. The terms fire resistant (FR) and flame retardant (FR) are used herein interchangeably. The comer guard 102 is attached between the mattress foundation 104 and the bed frame 108. The FR comer guard 102 serves to protect the comer of the mattress foundation 104 against wear and tear which might

otherwise occur when the mattress foundation 104 is being moved as well as during normal use. The FR corner guard 102 further provides protection for the bedding assembly 100 against heat and fire.

The mattress 106 typically includes a fabric or plastic covered structure having an internal construction configured to provide comfort for a person resting on the surface of the bedding assembly 100. The mattress 106 may include air mattresses, spring mattresses, and foam mattresses. The mattress foundation 104 may include an upper support surface that is sized and shaped to match the mattress 106, and a lower support surface configured to interfit with a bed frame 108. In certain embodiments, the mattress 106 and the mattress foundation 104 are rectangular in shape and therefore have four exterior corners. In such embodiments, the FR corner guard 102 may be positioned at each corner to provide complete protection for the bedding assembly 100.

The FR corner guard 102 is sized to extend from adjacent side surfaces of the mattress foundation 104 to cover at least a portion of the corner. The FR corner guard 102 may be configured to fit in between the bed frame 108 and the mattress foundation 104. FIG. 2A is a perspective view of an exemplary FR corner guard 102 used with bedding assembly 100 of FIG. 1. In particular, FR corner guard 102 is configured as a curved rigid member having a concave inner surface 202 and a convex outer surface 204. The FR corner guard further includes a support ledge 206 positioned at the based of the inner surface 202. The FR comer guard 102 may be positioned on the corner of the mattress foundation 104 such that the inner surface 202 contacts the mattress foundation 104 and the ledge 206 is positioned underneath the mattress foundation 104.

The FR comer guard 102 may include rigid materials. In certain embodiments, the FR comer guard 102 may be partially bendable so that it may be shaped to fit around a comer of the mattress foundation 104 during assembly. Alternative, the FR comer guard 102 may include stiff materials that are already pre-bent. The FR comer guard may include suitable impact-resistant, rigid and/or bendable materials. The FR comer guard may include at least one of polyethylene, and polypropylene. The FR comer guard may include other polymeric reagents without departing from the scope of the invention. The term polymeric

reagent may be used herein to refer to organic compounds, e.g., olefins, that form polymeric material upon initiation (e.g., peroxide initiated polymerization). Polymeric reagents may include at least one of thermoplastic polymers, thermoset polymer, rigid-foams and semi- flexible foam polymeric materials. Suitable thermoplastic materials may include, for example, polyethylene, polypropylene, polystyrene, acrylonitrile-butadiene-styrene copolymers, poly-alpha-methyl-styrene, polyvinyl chloride, poly(meth)acrylates, poly- acrylonitrile, polyamides, polycarbonates, and any blends of two or more thermoplastic polymers. Suitable thermoset polymeric materials may include, for example, epoxy resins, polyurethanes, high-hardness rubber, phenolic resins, and cross-linked polyesters. Suitable rigid-foam and semi-flexible foam polymeric materials may include, for example, phenolic foams, polyurethane foams and polystyrene foams. Silane-crosslinkable polymers may also be used i.e. polymers prepared using unsaturated silane monomers having hydrolysable groups capable of crosslinking by hydrolysis and condensation to form silanol groups in the presence of water and optionally a silanol condensation catalyst. The silane-crosslinkable polymer can be for example a copolymer of ethylene and an unsaturated silane monomer such as vinyl trialkoxysilane produced by copolymerising the monomers in a polymerisation reactor or by grafting the silane monomer onto a polyethylene backbone.

In certain embodiments, the FR corner guard includes traditional flammable polymeric reagents, as described above, that are combined with one or more FR agents or have an FR coating. FIGS. 2B and 2C depict cross-section views of the FR corner guard of FIG. 2A, according to various illustrative embodiments of the invention. In particular, FIG. 2B depicts a cross-sectional side view of the FR comer guard 102 cut along section lines 2- 2'. As previously described with reference to FIG. 2A, the FR corner guard 102 includes a inner surface 202 having a ledge 206. The outer surface 204 of the FR corner guard 102 is coated with one or more FR agents 210. FIG. 2C shows a FR corner guard 102 coated substantially on all sides with one or more FR agents. The thickness of the coating of FR agents may be substantially constant or may vary across the surface of the FR comer guard 102.

The FR agents used to coat the FR comer guard 102 may be selected based on the nature of the mechanism of flame retardancy. These mechanisms may be based on the

knowledge that certain materials are not combustible and/or are capable on their own or in combination with other compounds to impart flame retardant or fire resistant properties to materials which have been used in connection with such compounds or combinations of compounds. FR agents may include materials which have been used in connection with, or treated or modified by means of certain chemical compounds or mixtures of compounds to show reduced combustion rate compared to the corresponding non-treated or non-modified materials. FR agents may include chemical compounds which imparts to the material which has been used in connection with or treated or modified with the FR agent, a reduced combustion rate compared to the corresponding non-treated or non-modified material. Certain FR agents may, on thermal decomposition, produce water which in turn may provide FR capabilities.

In certain embodiments, the FR agent 212 and 214 used to coat the FR corner guard 102 may include a flame retardant intumescent (FRI) system, i.e., a system which has flame retardant, char- forming and intumescent properties. A plastic mass containing a flame retardant, char-forming and intumescent (FRI) system may typically under the effect of heat (fire) expand to form a non-flammable, multi-cellular layer of a char- foam which provides an efficient shielding and insulation for the underlying material against direct contact with fire and oxygen, as well as against heat transfer.

In certain embodiments, the FR agents 212 and 214 may be selected from brominated compounds, metal compounds, phosphorous compounds, and chlorinated paraffins. Exemplary FR agents that can be incorporated in the mixture of the invention include but are not limited to: hexabromocyclododecane, decabromodiphenyl oxide, alumina trihydrate, magnesium hydroxide, zinc borate, calcium and zinc molybdates, antimony trioxide, antimony pentoxide and sodium antimonate, ammonium polyphosphates, phosphonic acid, (3-{[hydroxymethyl]amino}-3-oxopropyl)-dimethyl ester, organic phosphonates, tris (monochloropropyl) phosphate, tris (l ,3-dichloropropyl-2) phosphate, aromatic phosphates plasticizers, tetrakis (hydroxymethyl) hydronium salts, and chlorinated paraffins.

In other embodiments, the FR agent 212 and 214 used to coat the FR corner guard 102 one or more hydrated inorganic fillers. Exemplary fillers for use in the composition of the present invention include those which, upon thermal decomposition, release or produce water. One class of hydrated inorganic fillers that can be used in the composition of the present invention is hydrated alkaline earth carbonates, such as hydrated magnesium carbonate and hydrated calcium carbonate. Hydrated mixed-metal carbonates, such as calcium magnesium carbonate, can also be used. Also, mixtures of the above metal carbonates, for example, mixtures of calcium carbonate and magnesium carbonate, may be used. Mixtures of the above metal carbonates and the above mixed-metal carbonates, for example, a mixture of calcium carbonate and calcium magnesium carbonate, may also be suitable. The hydrated alkaline earth metal carbonates may be used as such; however, alternatively or additionally, hydrated alkaline earth metal carbonate precursors can be used. Suitable hydrated alkaline earth metal carbonate precursors are those materials which generate alkaline earth metal carbonates upon processing or upon exposure of the resulting composition to sufficient heat. Examples of such hydrated alkaline earth metal carbonate precursors include alkaline earth metal bicarbonates, for example, magnesium bicarbonate and calcium bicarbonate. Another class of suitable hydrated inorganic fillers is the alkaline earth hydroxides, such as calcium hydroxide and, preferably, magnesium hydroxide. Aluminum trihydrate and hydrated zinc borate are other suitable hydrated inorganic fillers that can be used in the compositions of the present invention. Combinations of these hydrated inorganic fillers can also be employed, and "hydrated inorganic filler", as used herein, is meant to also include such combinations. The hydrated inorganic filler may be surface treated with an organic agent to improve dispersion of the filler within the polymer blend and to modify filler/polymer interfacial adhesion. Organic agents suitable for this purpose include fatty acids, vinylsilanes, aminosilanes, mercaptosilanes, epoxysilanes, and other organofunctional agents.

In certain embodiments, the FR agents 212 and 214 used to coat the FR corner guard 102 include one or more non hydroxide inorganic fillers. Exemplary inorganic fillers suitable for use in the flame retardant compositions may include inorganic compounds of a metal of Group II A such as compounds of magnesium and/or calcium. Examples of suitable

inorganic fillers are calcium carbonate, magnesium carbonate, magnesium oxide and huntite 2[Mg ₃ Ca(COs) ₄ ].

In certain aspects of the invention the FR agents may include silicone fluids and gums. Suitable examples for use in organic polymer compositions include for example organopolysiloxane polymers comprising chemically combined siloxy units selected from the group consisting OfR ₃ SiO _{0 5} , R ₂ SiO, RiSiOi ₅ , R ¹ R ₂ SiO _{0 5} , RR ¹ SiO, R' ₂ Si0, RSiOi ₅ and SiO ₂ units and mixtures thereof in which each R represents independently a saturated or unsaturated monovalent hydrocarbon radical, and each R ¹ represents a radical such as R or a radical selected from the group consisting of a hydrogen atom, hydroxyl, alkoxy, aryl, vinyl or allyl radicals. The organopolysiloxane has a viscosity of approximately 600 to 300 xlO ⁶ centipoise at 25 ⁰ C. An example of an organopolysiloxane which has been found to be suitable is a polydimethylsiloxane having a viscosity of approximately 2O x 10 ⁶ centipoise at 25. °C. The silicone fluid or gum can contain fumed silica fillers of the type commonly used to stiffen silicone rubbers e.g. up to 50% by weight. The amount of silicone fluid or gum included in the composition according to the present invention can be from 0.5 to 100, preferably from 2 to 45, parts by weight per hundred parts by weight of the organic polymer.

As noted above, FIGS. 1 -2C depict an FR corner guard used on an exterior corner portion of a bedding assembly. FIGS. 3-4C depict an FR corner guard 302 that may be similar to coiner guard 102, but attached to box spring in the interior of a bedding assembly 300. In particular, FIG. 3 is an inside perspective view of a bed box spring 301 , according to an illustrative embodiment of the invention. The corner guard 302, in accordance with the present invention, is mounted on a box spring 301. The box spring 10 comprises a base 306, a wire grid, and upright supports 308. An FR comer guard 302 is attached to a comer of the box spring 301.

FIG. 4A is a perspective view of an exemplary FR comer guard used with the box spring of FIG. 3. The FR comer guard 302 includes a rectangular shaped body curved along a longitudinal axis with inner concave surface 404. The inner surface 404 includes an upper ledge 406 and a lower ledge 408 for securing the FR comer guard 302 to the box spring 301. The FR comer guard 302 also includes a plurality of strengthening members 410 extending

along the longitudinal axis. The FR comer guard 302 may be similar to FR corner guard 102 for FIG. 2A. FR corner guard 302 may also be coated with one or more FR agents to provide protection against heat and fire. FIGS. 4B and 4C depict cross-section views of the FR corner guard 302 of FIG. 4A, according to various illustrative embodiments of the invention. In particular, FIG. 4B shows the FR corner guard 302 coated with one or more FR agents 412 on an outer surface and FIG. 4C depicts the FR corner guard 302 coated on substantially all its surface with FR agents. The FR corner guard 302 includes materials and FR agents similar to those described with reference to FIGS. 2A-2C.

As noted earlier, FR agents may be coated as layers on one or more surface of the

FR corner guard 102 and 302 to provide FR capabilities. In certain embodiments, the FR agents may be intermixed with the FR corner guard material. For example, traditional polymeric reagents may be mixed with suitable FR agents, described earlier, to form the raw materials for building an FR corner guard. In certain embodiments, the FR agents may be mixed in with traditional polymeric reagents during an injection molding process to form a corner guard having FR properties therein.

FIG. 5 depicts an exemplary injection molding system 500 for manufacturing an FR corner guards similar to corner guards 102 and 302. The injection molding system includes a mold 502 held between adjustable clamps 504, 506 and 508 within a clamping system 510. The system 500 includes an injection barrel 512 connected through a nozzle 522 to the mold 502. The injection barrel 512 includes one or more heating elements 520 for heating the polymeric resin and a piston to push the resin through the barrel. The system further includes hoppers 514 and 530 connected to the injection barrel 512 for feeding resin and FR agents into the mold 502. Hopper 514 includes feedthrough tubes 518 and 516. The system also includes other components such as hydraulic motors 524, gears and pumps 526. The system may be placed on a base 528 for stability.

During operation a polymeric resin or reagent is fed into the injection barrel 512 through a tube 518 and hopper 514. Hydraulic components 524 and 526 operate a piston and push the resin through the injection barrel 512 and towards the heating elements 520. The resin is heated to an appropriate melting temperature and passed through the nozzle 522

and injected into the mold 502. The mold 502 typically receives the molten resin and forms the shape of the FR corner guard. The mold may be cooled constantly to a temperature that allows the resin to solidify and be cool to touch. The mold may be held together by hydraulic or mechanical force by clamping system 510. In certain embodiments, the polymeric reagents or resins are combined with suitable FR agents, discussed above. The FR agents may be mixed prior to heating through tube 516 in the hopper 514. Alternatively, the FR agents may be combined with molten resin via hopper 530.

In certain embodiments, the polymeric resin or reagent may be combined with the FR agent using conventional compounding or blending apparatus, e.g. a Banbury mixer, a 2- roll rubber mill or a twin screw extruder. Generally, the composition can be prepared by blending them together at a temperature which is sufficiently high to soften and plasticize the organic polymer, typically a temperature in the range 120. °C to 300. °C.

In certain embodiments, all ingredients are formulated together except those which are sensitive to the temperatures in the range of from about 150 °C. to about 200. ⁰ C, such as heat decomposable peroxides. The ingredients are therefore at a temperature sufficient to soften and plasticize the particular organic polymer if feasible. An effective procedure, for example, would be to uniformly blend the aforementioned ingredients at a suitable temperature omitting the organic peroxide, then introduce the organic peroxide at a lower temperature to uniformly incorporate it into the mixture. In certain embodiment, the polymerized FR mixture can be molded, extruded, cast, or manufactured in any similar manner of a plastic material to form corner guard.

In certain embodiments, instead of mixing traditional polymeric reagents with FR agents, the FR comer guard may include polymeric agents having inherent FR properties such as polyvinylchloride. Such FR polymeric reagents may contain halogen atoms or various other functional groups, e.g. substituted aryl groups, phthalimide groups, 4-4'- bishydroxydeoxybenzoin, which provide FR properties to the plastic material.

In certain alternative embodiments, the FR corner guard 102 and 302 may include other materials to reinforce the corner guard. Forming a reinforced corner guard may be

achieved, for example by means of mineral fillers and/or fibrous materials, such as e.g. talc, clays, glass-fibers, carbon-fibers, mineral fibrous material, plastic fibers, textile fibers or metal filaments. The fibrous material may be used in the form of continuous strands, woven or non-woven or meshed sheets or randomly distributed chopped fibers. The surfaces of these fibrous reinforcement materials may furthermore be treated in a conventional manner to improve adhesion between the fibrous material and the plastic material.

In other embodiments, the FR corner guard may also include conventional additives used in the art, such as plasticizers and anti-oxidants. The FR corner guard according to the present invention may include materials that may be crosslinkable. As an example, thermoplastic polymer compositions may be crosslinked using crosslinking agents such as organic peroxides and the compositions according to the present invention can contain a crosslinking agent in a conventional amount. If desired, heat activated peroxides can be employed when utilizing polyolefins as the organic polymer. Suitable reactive peroxides are disclosed in U.S. Pat. Nos. 2,888,424, 3,079,370, 3,086,966 and 3,214,422 (all incorporated herein by reference). Suitable peroxide crosslinking agents include organic tertiary peroxides which decompose at a temperature above about 146. °C. and thereby provide free- radicals. The organic peroxides can be used in amounts of from about 2 to 8 parts by weight of peroxide per 100 parts of organic polymer. An exemplary peroxide is dicumyl peroxide, while other peroxides such as VulCupR.RTM. of Hercules, Inc., a mixture of para- and meta-, -bis(t-butylperoxy)-diisopropylbenzene, etc., can be used. Curing co-agents such as triallyl cyanurate can be employed in amounts of up to about 5 parts by weight of co-agent, per 100 parts of the polymer if desired. The polyolefins can be irradiated by high energy electrons, X-ray and like sources. Silane-crosslinkable polymers can contain a silanol condensation catalyst.

In light of the all that is disclosed above, those skilled in the art will know or be able to ascertain using no more than routine experimentation, many equivalents to the embodiments and practices described herein. Accordingly, it will be understood that the invention is not to be limited to the embodiments disclosed herein, but is to be understood from the following claims, which are to be interpreted as broadly as allowed under the law.