Heat-resistant flame-retardant coating

Abstract

The present disclosure relates generally to heat resistant, flame retardant coating compositions and related methods of use. More particularly, the present disclosure relates to heat resistant, flame retardant coating compositions comprising at least one polycation, at least one polyanion, and at least one plasticizing salt.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 514,005, filed July 17, 2023, which is incorporated herein by reference as if fully set forth herein. Technical Field

[0003] This disclosure generally relates to heat-resistant and flame-retardant coating compositions and related methods of application. More particularly, this disclosure relates to heat-resistant and flame-retardant coating compositions comprising at least one polycation, at least one polyanion, and at least one plasticizer salt. Background Technology

[0004] Fire-related accidents cause widespread property damage and injury. It is well known that many commonly used materials are flammable. To reduce the hazards posed by such flammable materials, flame retardants have been developed. Such flame retardants include halogenated materials. Halogenated materials typically include brominated compounds and halogen-substituted compounds. The disadvantages of such halogenated materials include the potential for harm to the environment and humans. For example, such halogenated materials can form poisons. Other disadvantages include a lack of durability, which may be typical for brominated compounds in some cases.

[0005] For polymer materials to ignite, some form of degradation must occur. When polymers thermally decompose, they break down into generally volatile constituent molecules and free radicals. If the temperature is above the ignition temperature or a suitable ignition source is found, these molecules and free radicals enter the gas phase and burn with atmospheric oxygen. Combustion is an exothermic process that cycles the heat energy back to the underlying material, causing more material to decompose and providing additional fuel for combustion. The interface region between the flame and the polymer is crucial because it allows volatile constituent molecules and free radicals to continue to be generated, and the reaction to continue.

[0006] To make a material flame-retardant, the circulation must be stopped to stop adding fuel to the fire. A flame without fuel will extinguish. Therefore, it is important to develop materials and coatings that can provide both heat resistance and flame retardancy without using halogenated compounds. Summary of the Invention

[0007] Exemplary embodiments relate to compositions comprising: about 0.1 wt% to about 20 wt% of at least one polycation; about 0.1 wt% to about 50 wt% of at least one polyanion; and about 0.1 wt% to about 35 wt% of at least one plasticizer salt. This embodiment or another exemplary embodiment may specify that at least one of the polycations is polyethyleneamine, polyallylamine hydrochloride, and a combination of polyethyleneamine and polyallylamine hydrochloride. This embodiment or another exemplary embodiment may specify that the weight percentages of polyethyleneamine and polyallylamine are equal. This embodiment or another exemplary embodiment may specify that the weight percentage of polyethyleneamine is about 0.1 wt% to about 20 wt%. This embodiment or another exemplary embodiment may specify that the weight percentage of poly(allylamine) is about 0.1 wt% to about 20 wt%. This embodiment or another exemplary embodiment may specify that the at least one polyanion includes ammonium polyphosphate. This embodiment or another exemplary embodiment may specify that the at least one plasticizer salt includes ammonium pentaborate tetrahydrate. This embodiment or another exemplary embodiment may specify about 0.1 wt% to about 4 wt% of a crosslinking agent. This implementation or another exemplary implementation may specify that the crosslinking agent includes tetrahydroxymethyl chloride. This embodiment or another exemplary embodiment may specify about 0.1 wt% to about 30 wt% of boric acid. This embodiment or another exemplary embodiment may specify about 0.1 wt% to about 3 wt% of calcium chloride. This embodiment or another exemplary embodiment may specify at least about 0.1 wt% to about 15 wt% of a carbonization accelerator. This embodiment or another exemplary embodiment may specify that the carbonization accelerator is pentaerythritol.

[0008] Another embodiment relates to a method for manufacturing a heat-resistant and flame-retardant multilayer laminate, comprising: providing a polymer or paper face layer; providing a polymer adhesive layer; providing a polymer topcoat; depositing a heat-resistant and flame-retardant composition on the polymer topcoat, wherein the composition comprises about 0.1 wt% to about 20 wt% of at least one polycation, about 0.1 wt% to about 50 wt% of at least one polyanion, and about 0.1 wt% to about 35 wt% of at least one plasticizer salt; and sandwiching the face layer between the topcoat and the adhesive layer. This embodiment or another exemplary embodiment may specify that the deposition includes spraying. This embodiment or another exemplary embodiment may specify that at least one of the polycations in the composition is polyethyleneamine, polyallylamine hydrochloride, or a mixture thereof. This embodiment or another exemplary embodiment may specify that the at least one polyanion in the composition includes ammonium polyphosphate. This embodiment or another exemplary embodiment may specify that the at least one plasticizer salt in the composition includes ammonium pentaborate tetrahydrate. This embodiment or another exemplary embodiment may specify that the composition further comprises about 0.1 wt% to about 4 wt% of a crosslinking agent. This embodiment or another exemplary embodiment may specify that the composition further comprises tetrahydroxymethyl chloride. . Attached Figure Description

[0009] Figure 1 Several exemplary polyelectrolyte structures are shown.

[0010] Figure 2 The photograph shows the performance of the various embodiments and comparative examples discussed herein under a flame exposure test for 2.0 seconds.

[0011] definition

[0012] As used in this article, "gsm" means grams per square meter.

[0013] As used herein, with respect to laminated constructions, the term "multilayer" means a face material having one or more additional layers coated with an adhesive. Non-limiting examples of such layers constituting a multilayer include protective layers, spacer layers, adhesive layers, layers containing optical components, metallic layers, barrier layers, release liner, bonding coatings, transparent layers, colored layers, white layers, reflective layers, fluid transfer layers, strength-enhancing layers, face coatings, print-receiving layers, printable layers, marking layers, functional layers, and combinations thereof. The multilayer laminated constructions described herein can be used in a variety of applications, including but not limited to: graphic applications, such as automotive and architectural packaging; reflective applications, such as road and traffic signs, trains and other commercial vehicles; and labeling and packaging applications for battery tags; and so on.

[0014] As used herein, the term "surface-treated area" refers to a region of material without a clearly defined boundary. A surface-treated area typically includes a coating and extends into an area containing both the coating material and the substrate material, into which the coating may penetrate, diffuse, or at least partially migrate. The term "surface treatment" refers to the treatment of a surface, such as a substrate surface, by applying a coating, resulting in no clearly defined boundary between the coating and the substrate.

[0015] As used herein, the terms "halogen-free" or "halogen-free" refer to the inclusion of hydrochloride salts, as these are either produced solely by the reaction of hydrochloric acid with an organic base (e.g., amines) or are considered to be acid salts produced by the reaction of hydrochloric acid with an organic base (e.g., amines). Converting amines into their hydrochloride salts is a common way to improve their water solubility and storage stability, which may be desirable for substances including those discussed herein. Furthermore, this can be extended to the addition of salts combined with chloride or ionic chloride salts as alternatives to plasticizers. Compounds. Detailed Implementation

[0016] Generally, this specification discloses a topcoat or novel protective film or laminate having at least one main surface of a material-treated substrate to enhance the properties of the laminate while retaining a sufficient portion of the properties of the coating material, such as transparency, flexibility, and / or ductility. In particular, the proposed surface treatment can be a conventional topcoat or topcoat layer, or a surface treatment in which a large portion of the material applied during the surface treatment does not ultimately remain above or on top of the treated upper surface of the underlying film or laminate. That is, the coating material applied during the surface treatment is located on top of the substrate of the underlying film / laminate or can penetrate the substrate of the underlying film / laminate and / or fill recesses or depressions on the rough surface of the underlying film / laminate, rather than forming a largely different layer with well-defined boundaries on top of the underlying film or laminate. The coating materials used in the surface treatment typically include liquid coatings. The coating solution is typically a transparent liquid in which the coating components are completely soluble in an organic solvent or water, or whose dimensions are smaller than the visible wavelength of light and therefore do not scatter light. A coating dispersion is a coating liquid that appears turbid because the coating components are not completely soluble in organic solvents or water, or are not completely miscible with organic solvents or water, or because their size is larger than the visible wavelength of light and they scatter light.

[0017] The diffusion of the treatment material into the plastic film substrate and the formation of the gradient transition layer largely contribute to maintaining the desired film or laminate properties. This is especially true when the treatment material comes from a protective composition as illustrated in the embodiments herein. Several mechanisms can contribute to the diffusion and formation of the gradient transition. The outermost surface of the film, particularly the polymeric material, is typically rough at the nanoscale. When treated with a coating material, the recessed areas are filled with the coating material, which also advantageously achieves a smoother surface. In any case, at least in part due to these effects, as can be seen at magnification, the thickness and / or amount of the coating material remaining above or above the top surface of the underlying substrate material is relatively small relative to the coating weight used to apply the treatment material. In fact, in some embodiments, it may even be imperceptible.

[0018] There is reason to believe that smaller components and / or those with good affinity for plastic films will diffuse faster than larger components and / or those with poor affinity. Since typical coating formulations contain a variety of components that differ in size and / or affinity / compatibility with the film, the composition of the coating material that has diffused / migrated into the film may be substantially different from that of the starting formulation. This, in turn, results in a new composition of the coating retained on the film that also differs from that of the initial coating formulation.

[0019] adhesives

[0020] The laminates / constructs described herein comprise one or more adhesives. The adhesive can be a pressure-sensitive adhesive (PSA), a non-pressure-sensitive adhesive, a hot-melt adhesive, or a combination thereof. In some embodiments, the adhesive is a PSA. The PSA can be any known PSA. In some embodiments, the PSA is a solvent-based adhesive, an emulsion adhesive, or a non-emulsion adhesive. In some embodiments, the PSA is an emulsion adhesive. Hot-melt PSAs may also be used. The adhesive can be an acrylic adhesive or any other available adhesive having the required hardness and adhesive properties for the laminate and / or the adhesive-coated face material. In some embodiments, the adhesive should have sufficient hardness to prevent the adhesive from being extruded from the laminate or article during processing.

[0021] Exemplary PSAs can be found in (1) Encyclopedia of Polymer Science and Engineering, Volume 13, Wiley-Interscience Publishers (New York, 1988); (2) Polymer Science and Technology, Volume 1, Interscience Publishers (New York, 1964); (3) those described in U.S. Patent Nos. 5,164,444, 5,183,459, and 5,264,532 (all granted to Bernard) and U.S. Patent No. 5,385,965 (granted to Bernard et al.); and (4) combinations thereof. The PSA can be a solvent-based adhesive or a water-based adhesive. Conventional PSAs, including acrylic PSAs, rubber-based PSAs, and silicone-based PSAs, can be used in the laminates / constructs described herein. In one embodiment, the pressure-sensitive adhesive comprises an acrylic emulsion adhesive.

[0022] In some embodiments, the pressure-sensitive adhesive is prepared by polymerizing alkyl acrylates, vinyl acrylates, diesters of dicarboxylic acids, and unsaturated acids. Alkyl acrylates typically contain about 2 to about 12, or about 4 to about 8, carbon atoms in the alkyl group. Examples of alkyl acrylates include, but are not limited to, ethyl acrylate, n-butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, and isooctyl acrylate, with 2-ethylhexyl acrylate being preferred. In one embodiment, the alkyl acrylate is present in an amount of at least about 35%. In some embodiments, the alkyl acrylate is present in an amount of about 35% to about 60% by weight.

[0023] Vinyl esters typically have about 2 to about 12, or about 4 to about 8, carbon atoms in the alkyl group. Examples of vinyl esters include, but are not limited to, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl tert-carbonate, etc., wherein vinyl acetate is preferred. In some embodiments, the vinyl ester is present in an amount of about 15% to about 35% or about 20% to about 25% by weight.

[0024] Diesters of dicarboxylic acids include alkyl esters of unsaturated diacids such as maleic acid or anhydrides and fumaric acid. The alkyl group typically contains about 2 to about 20, about 4 to about 16, or about 6 to about 12 carbon atoms. Examples of diesters of diacids include, but are not limited to: butyl fumarate, octyl fumarate; hexyl maleate, decyl maleate; di-2-ethylhexyl maleate; dibutyl fumarate; and di-2-ethylhexyl fumarate; and mixtures thereof. In some embodiments, the diester of the diacid is present in an amount of about 20% to about 35% by weight.

[0025] Unsaturated acids typically contain about 2 to about 12, or about 2 to about 6, carbon atoms. Examples of unsaturated acids include, but are not limited to, acrylic acid, methacrylic acid, itaconic acid, etc. In some embodiments, the unsaturated acid is present in an amount of about 1% to about 3% or up to 5% by weight.

[0026] In an exemplary embodiment, the coating weight of the adhesive can be from 2 gsm to 100 gsm.

[0027] Release liner

[0028] In some embodiments, the laminate described herein may include one or more release liner pads. The liner may have a first side, a second side opposite the first side, a first edge, and a second edge opposite the second edge. The liner may be any available liner providing the necessary support and release properties. The liner may be made from a variety of materials, including but not limited to paper or polymer film liner pads, or derived from a variety of materials, including but not limited to paper or polymer film liner pads. In one embodiment, the paper thickness is sufficient to die-cut the resulting laminate or article. For example, for PET liner pads, the liner thickness may range from about 18 mm to 23 mm. In one embodiment, the liner pad has a lay-flat property. In some embodiments, the liner pad has a machine glaze or finish. In some embodiments, the liner pad has a silicone retaining layer. This retaining layer provides adhesion between the release coating and the release liner pad. The silicone retaining layer also prevents the silicone release coating from seeping into the liner pad.

[0029] In the case of paper pads and other absorbent pads, these pads have a moisture content. The moisture content can be varied and modified in various ways to promote, prevent, or optimize the patterning of the pad based on this moisture content. The methods will be discussed further below.

[0030] In some embodiments, the release liner includes a liner with a release coating. The release coating of the release liner provides a peelable bond with PSA or other adhesives. The release coating can be any composition that provides the desired peelable bond strength.

[0031] In one embodiment, the release coating is a silicone release coating. This release coating can be prepared by curing a silicone polymer in the presence of a controlled-release agent. In some embodiments, the controlled-release agent is of the formula R3SiO. 1 / 2 Monofunctional organosilicon units and tetrafunctional organosilicon units SiO 4 / 2The copolymer, wherein R is an alkyl or alkenyl group. In one embodiment, the alkyl or alkenyl group contains about 1 to about 12, or about 1 to about 6 carbon atoms. Non-limiting examples of alkyl and alkenyl groups include methyl, ethyl, propyl, butyl, hexyl, vinyl, propenyl, butenyl, and hexenyl.

[0032] The controlled-release agent typically reacts with a polysiloxane. The polysiloxane can be any polysiloxane that can be used to form a release coating. Examples of usable polysiloxanes include, but are not limited to, vinyl-terminated, hydroxyl-terminated, and epoxy-terminated polysiloxanes. In one embodiment, the polysiloxane is a functionalized polydialkylsiloxane, wherein the alkyl group contains about 1 to about 6 carbon atoms. The alkyl group independently includes, but is not limited to, methyl, ethyl, propyl, butyl, pentyl, hexyl, or mixtures thereof. In one embodiment, the alkyl or alkenyl group contains 1 to about 12, or 1 to about 6 carbon atoms. The viscosity-average molecular weight of the polysiloxane is typically greater than 300,000 centipoise (cps). In another embodiment, the viscosity-average molecular weight of the polysiloxane is about 300,000 to about 1,000,000 or greater. The polysiloxane can be represented by formula (I):

[0033] RO((Si(R)2O) x )—Si)—R (I)

[0034] Where R is independently defined as above, and x is an integer.

[0035] In some embodiments, the release coating is prepared using a crosslinking agent. In some embodiments, the crosslinking agent is a reactive polysiloxane, such as a polydialkylsiloxane or a polyhydroxyalkylsiloxane. The alkyl group is the same as those described above.

[0036] Release coatings can be applied in solvent-based, solvent-free, or emulsion form. To form a release coating, it can be cured by any known curing process, such as heat or radiation. This curing can be catalyzed by organosilicon-soluble complexes of Group VIII transition metals, such as platinum.

[0037] Commercially available release agents include, but are not limited to, GE SS-4335 (a silicone release agent in non-reactive solvents). Commercially available polysiloxanes include, but are not limited to, GE SS-4331 (a vinyl-terminated polydimethylsiloxane). Commercially available linkers include, but are not limited to, GE SS-4300C (a polymethylvinylsiloxane). Exemplary catalysts include, but are not limited to, SS-8010 catalyst in toluene. These materials are commercially available from General Electric Company’s Silicone Products Division. Similar silicone products are available from Dow Corning Corporation under the trade name Syl-off.

[0038] It will be understood that the subject matter of this invention is not limited to any release coating or release agent mentioned, but includes virtually any release coating or release agent suitable for the intended end-use application. Furthermore, while the subject matter of this invention has been described in conjunction with release liner, it will be understood that a suitably configured carrier film and other components can be used instead of the release liner.

[0039] surface material

[0040] Suitable face materials include, but are not limited to: synthetic paper, such as polyolefin and polystyrene types; various plastic films or sheets, such as polyolefins, polyvinyl chloride, polyethylene terephthalate, polystyrene, polyurethane, polymethacrylate, and polycarbonate. Further examples of suitable face materials include paper and paperboard. The face material can be or may include multilayer polymer sheets. The multilayer can be co-extruded, or the multilayer can be laminated together. In one embodiment, the face material includes both co-extruded multilayers and laminated multilayers. Furthermore, a white opaque film can be formed and used as a face material by adding a white pigment to one or more of the aforementioned synthetic resins. In one embodiment, a foamed film is used as the face material. The foamed film can be formed by conventional foaming operations. In another embodiment, the face material can be a laminate formed by combining multiple single-layer sheets composed of the materials listed above. Examples of such laminates include: a combination of cellulose fiber paper and synthetic paper, and a laminate of combined cellulose fiber paper and plastic film or sheet. In another suitable embodiment, the face material includes coated and uncoated paper, metallized paper, aluminum foil, laminated paper, and paper with a polymer material extruded onto its surface. In some variations, the face material may be coated with a liquid-absorbing material. The selected face material may be porous or semi-porous. The face material may exhibit certain visibility characteristics such as opacity, color, and / or brightness. The face material may include water-absorbing properties or other liquid-absorbing properties. The face material may be conductive and / or include conductive coatings or areas. A variety of commercially available face materials may be used, such as those available under the name TESLIN.

[0041] The thickness of the sheet material is optionally determined with reference to application-specific standards. Such standards may include the desired end use. In one embodiment, the sheet thickness is in the range of about 10 μm to about 300 μm. In another embodiment, the sheet thickness is in the range of about 20 μm to about 200 μm. In yet another embodiment, the sheet thickness is in the range of about 30 μm to about 150 μm. Optionally, the sheet material may be treated with a primer, corona discharge, or plasma to increase the bonding strength between the sheet material and the dried topcoat composition formed on the surface of the sheet material.

[0042] In some embodiments described herein, the surface material exhibits one or more functions or functional properties. For example, the surface material may be selected to achieve or facilitate: indication, such as visual indication of liquids; venting, such as guiding or allowing air or gas flow through the thickness of the surface material; retention of water or liquid within the surface material; electrical discharge or conductivity of the surface material; chemical transport through the thickness of the surface material; acoustic passage through the thickness of the surface material; and / or combinations of these functions or properties.

[0043] Optional Layer

[0044] The adhesive-coated surface materials and / or laminates described herein may include one or more additional layers or components. Non-limiting examples of such layers include: protective layers, bonding coatings, transparent layers, colored layers, white layers, reflective layers, fluid transfer layers, strength promoting layers, surface coatings, print-receiving layers, printable layers, marking layers, functional layers, etc.

[0045] Laminated properties

[0046] The laminates described herein may possess specific and useful properties or functions. In some embodiments, the techniques described herein enable the formation of laminates in which the transfer, propagation, and / or migration of liquids, gases, sound waves, electric currents, and / or other reagents or elements can occur and be controlled to pass through or through the laminate in the Z direction. As mentioned herein, the “Z direction” refers to the direction through the thickness dimension of the laminate or a portion thereof; therefore, the “X direction” and / or “Y direction” mentioned refer to directions perpendicular to the Z direction and correspond to the width and length dimensions of the laminate.

[0047] Non-limiting representative examples of laminates with specific functions provided by the subject matter of this invention include liquid indicator laminates, venting laminates, water-absorbing laminates, sound channeling laminates, conductive laminates, and laminates having combinations of these functions and / or laminates having one or more of these functions and combinations of other functions.

[0048] For example, liquid indicator laminates can be produced such that the rate of indicator color change is related to the choice of face material and the properties of the porous adhesive. Discontinuous structures (e.g., created by pores in the adhesive layer or region) can allow, for example, liquid to flow from one side of the adhesive through the discontinuous adhesive to the other side and produce permanent color changes when dyes or other reagents in the functional coating of the laminate dissolve.

[0049] In one embodiment, a liquid indicator laminate is provided. The rate or speed of the indicator color change is related to surface material properties such as the absorbency of the liquid and the porosity of the patterned adhesive in the Z direction. The indication is typically irreversible and can be measured by color change or by simple visual comparison.

[0050] Discoloration of a laminate's surface or region can be measured and quantified by optical changes, such as through CIE Labs, or by simple visual comparison. Discoloration can be permanent or non-permanent. It can also be temporary and revert to its initial state after a period of time. In some implementations, this time period is predetermined.

[0051] This phenomenon of transmission through discontinuities in the adhesive in the Z direction can be achieved in other labeling applications, particularly pressure-sensitive adhesive labels, such as those used for venting the substrate, for example, by means of air channels in the Z direction; and for marking a moist substrate, for example, by means of liquid channels in the Z direction, discharge in the Z direction, chemical transport from one layer to another in the Z direction, and / or acoustic channels in the Z direction. This phenomenon allows a medium or reagent to pass through, transfer, and / or migrate from one side of the adhesive region of the laminate to the other side of the adhesive region. Although medium penetration or transmission is referred to as being in the Z direction, it will be understood that the subject matter of the invention is not limited to this and may also include penetration / transmission in the X and / or Y directions.

[0052] In some embodiments, the laminate described herein includes layers or regions of a secondary adhesive. The secondary adhesive is typically used to adhere the laminate to a target substrate. The secondary adhesive may comprise one or more adhesives that are the same as or different from the patterned or porous adhesive. A description of representative examples of secondary adhesives is provided herein. In such an adhesive configuration, a primary adhesive may be applied to a facestock, a secondary adhesive may be applied to a release liner, and the applied adhesive and release liner may be laminated together such that the primary adhesive and secondary adhesive are in direct contact with each other. Alternatively or additionally, both the primary adhesive and secondary adhesive may be applied to either the facestock or the release liner and then laminated together. The layering of the primary adhesive and secondary adhesive relative to the facestock and release liner is contemplated to be facestock, primary adhesive, secondary adhesive and release liner, or facestock, secondary adhesive, primary adhesive, release liner. Regardless of the order of the primary and secondary adhesives, given that the other adhesive may be continuous, at least one of the primary and secondary adhesives is contemplated to be patterned.

[0053] In some embodiments, a range of different arrangements of layers and components can be utilized. In some embodiments using a patterned adhesive (e.g., a layer of discontinuous adhesive), the layer is disposed between the functional face material and the pad or functional layer. Furthermore, in liquid indicator laminates, the patterned adhesive may be disposed between the functional face material and a layer or region of the functional reagent sensitive to liquids passing through the laminate. Additionally, in liquid indicator laminates, a layer or region of the functional reagent may be disposed between the patterned adhesive and the carrier layer.

[0054] The techniques and features described herein enable the production of adhesive-coated laminates and / or adhesive-coated face materials having fluid / air management properties, controlled removability, and / or unique thermal and / or electrical conductivity. Furthermore, the use of these techniques and features enables the reduction of materials, such as adhesives, and thereby enables cost savings. However, it will be understood that the subject matter of this invention includes the adhesive-coated face materials and laminates described herein formed by methods other than those described herein.

[0055] Topcoat formulations and applications

[0056] In the exemplary embodiments discussed herein, a surface coating is deposited on a substrate using any suitable method. Suitable methods in these embodiments include any suitable coating techniques. Embodiments include depositing a coating on a substrate using any suitable liquid deposition method. Without limitation, examples of suitable methods include bath coating, spray coating, slot coating, spin coating, curtain coating, gravure coating, reverse gravure printing coating, reverse roll coating, roller-squeezed (i.e., gap) coating, metering bar coating, air knife coating, or any combination thereof. Bath coating includes immersion or soaking in an aqueous solution. In one embodiment, the coating is deposited by immersion in an aqueous solution. In other embodiments, the coating is deposited by spraying an aqueous solution.

[0057] This disclosure specifically relates to the deposition of polyelectrolyte complex (PEC) coatings on a membrane substrate using the application of polyelectrolyte complex aggregates. Solutions including this utilize a "one-pot" aqueous solution. This method produces coatings with flame-retardant (FR) properties comparable to those obtained using layer-by-layer (LbL) assembly methods, while employing far fewer processing steps. By controlling the electrostatic interactions between the dissolved polyelectrolytes, a stable polymer solution can be deposited and cured.

[0058] To avoid additional processing steps caused by buffering, this method can be further simplified by generating polyelectrolyte complex agglomerates to deposit all the components required for a flame-retardant coating in a single step. Agglomerates are condensed phases with liquid-like droplets, typically formed from polymer molecules with opposite charges. They are extensively studied in colloid and interface science due to their significant material properties. Agglomeration occurs by mixing two polyelectrolytes with complementary charges, which typically results in the precipitation of a solid polyelectrolyte complex from solution, but the ionic interactions between the polymers can be shielded by adding a salt. This results in three potential “phases” of the polyelectrolyte mixture: a solid complex, a viscous agglomerate with a high polymer concentration, and a solution in which ionic crosslinking is completely shielded by the added salt. Agglomerates can be applied by rod / strip coating or flexographic printing to produce conformal flame-retardant coatings. This method has been shown to impart gas-barrier properties to PET films. Furthermore, polyelectrolyte complexes deposited in a two-step process have been shown to impart flame-retardant properties to a variety of textiles. In both cases, the resulting coatings exhibit properties comparable to LbL coatings with significantly lower complexity.

[0059] It is speculated that the condensation of polyelectrolytes used in the flame-retardant PEC / LbL coating is an effective flame-retardant treatment for PET films. Figure 1Several exemplary polyelectrolyte structures are shown. Initial work focused on developing flame-retardant aggregates comprising polyamines (e.g., polyethyleneimine or PEI and polyethyleneimine or PVAm) and sodium polyphosphate (or poly(sodium phosphate), PSP). It was found that while PEI / PSP aggregates form relatively effective coatings, once coated, these aggregates cannot be converted back into solid complexes (a barrier to coating durability).

[0060] It was determined that PVAm / PSP aggregates (which can form solid complexes by altering salinity due to their ability to accept various synergistic additives) could be incorporated, making them an ideal candidate for developing halogen-free flame-retardant treatments for PET films. The combination of PVAm / APP / ammonium pentaborate (APB), where APB acts as a plasticizing salt, was then tested. After several formulation adjustments, tetra(hydroxymethyl)chlorination... (THPC) crosslinked PAAm / APP / APB consistently achieved a VTM-0 rating at 22 gsm, comparable to the control (referred to as the control system and hereinafter referred to as Comparative Example 2).

[0061] The exemplary polycationic materials disclosed herein include, but are not limited to, amine-containing compounds and imine-containing compounds. Specifically, exemplary embodiments may include PVAm, PAAm, and PEI. In exemplary embodiments, at least one polycationic material is used and the amount of the polycationic material is from about 0.1 wt% to about 20 wt%. Sometimes, when a mixture of polycationic materials is used in exemplary embodiments, the respective weight percentages may be the same. For example, a mixture of PVAm and PAAm may each have equal weight percentages of about 0.05 wt% and about 10 wt%, thereby equaling the total amount of about 0.1 wt% and about 20 wt% in the composition.

[0062] The exemplary polyanionic materials disclosed herein include, but are not limited to, polyphosphate compounds. Specifically, exemplary embodiments may include PSP and APP. In exemplary embodiments, at least one polyanionic material is used and the amount of the polyanionic material is from about 0.1% by weight to about 50% by weight.

[0063] The exemplary plasticizers of this disclosure are non-halogenated. Specifically, in one exemplary embodiment, APB is used as the plasticizer. In the exemplary embodiment, at least one plasticizer is used and the amount of the plasticizer is from about 0.1% by weight to about 35% by weight.

[0064] In various exemplary embodiments, other additives may optionally be used. For example, a solvent or carrier may be added to a particular embodiment. For example, in some embodiments, water may be used in amounts from about 0.1% by weight to about 70% by weight.

[0065] Furthermore, in some other embodiments, a crosslinking agent may be added. In an exemplary embodiment, the crosslinking agent is tetrahydroxymethyl chloride. It is added in amounts ranging from approximately 0.1% to 4% by weight.

[0066] In other embodiments, a crystallization inhibitor is added to the composition. In an exemplary embodiment, the crystallization inhibitor is boric acid and it is added in an amount of about 0.1% by weight to about 30% by weight.

[0067] In other embodiments, ionic salts may be added. In such embodiments, sodium chloride, calcium chloride, magnesium chloride, and mixtures thereof may be added. When used, the amount of the ionic salt is from about 0.1% by weight to about 3% by weight. In other embodiments, various polyvalent salts may be used because they can act as ionic crosslinking agents between negatively charged portions in the aggregate.

[0068] In other embodiments, a carbonization accelerator may be added. In such embodiments, pentaerythritol may be the added carbonization accelerator. When used, the amount of the carbonization accelerator is from about 0.1% by weight to about 15% by weight.

[0069] The percentages of the compounds discussed above can be expressed as wet or dry formulations. A wet formulation contains a certain amount of water, solvent, or carrier shortly after application, allowing the mixture to flow sufficiently for the coating application. A dry formulation is what remains after the wet coating has been dried by an external heater or under potential drying conditions following application. The percentage can be derived from the water content, depending on the initial amount of water contained. For example, if 50% by weight of water is used in a wet formulation, the concentration of the remaining components in the dry formulation will be doubled.

[0070] All solutions were prepared using 18 MΩ deionized (DI) water. Polyethyleneimine (Mw = 25,000 g / mol), hydrochloric acid (HCl, 37%), sodium hydroxide (NaOH, 98%), APB (99%), sodium chloride (NaCl, ACS reagent), THPC (80%), glutaraldehyde (GA, 50 wt% in solution), boric acid (BioReagent, 99.5%), calcium chloride, urea (ReagentPlus, 99.5%), diammonium hydrogen phosphate (98.0%), pentaerythritol (PER, 98%), and sodium metasilicate were purchased from Sigma-Aldrich (St. Louis, MO). Polyethyleneimine (PVAm) was supplied by Solenis (product name Xelorex-1300NA). Ammonium polyphosphate (soluble APP, trade name APP-W) was purchased from Century Multech (Flushing, NY). Poly(allylamine) hydrochloride (PAAm) was purchased from Beckmann-Kenko (Bassum, Germany). Vermiculite clay (VMT) was purchased from Specialty Vermiculite Corp. (Cambridge, MA). Montmorillonite clay (MMT) was purchased from BYK Additives Inc. (Wesel, Germany). Poly(ethylene oxide) (PEO, MW = 4,000,000 g / mol) was purchased from Polysciences (Warrington, PA). Divinyl sulfone (DVS, 96%) was purchased from TCI America. Avery Dennison (AD) provided polyethylene terephthalate (PET) films (25.4 µm thick) as substrates for testing. Commercially available flame-retardant treated PET (referred to as the control) was provided for comparison with the formulations contained herein.

[0071] The resulting coating can be applied to either side of the substrate to which fire protection is desired. Although it is called a topcoat, it can be a coating on either side of the material. For example, in some embodiments, the topcoat will be applied to the interior of the material because potential fires may originate from internal locations. In other embodiments, it can be applied to the exterior of the material because the fire risk itself may originate from the outside. In yet another embodiment, it can be applied to both sides to prevent fire risks from both directions.

[0072] Condensate preparation

[0073] Prepare separate equimass solutions of PVAm, PAAm, or a combination of both (15 wt%) and APP (45 wt%) and shake until homogeneous. Add APB to the polycationic solution and dissolve as much as possible, then pour into the APP solution and stir until homogeneous (yielding a solution of 7.5 wt% PVAm or PAAm and 22.5 wt% APP). Then anneal the mixture in a 70°C oven for approximately 72 hours, after which turn off the oven and allow the mixture to cool slowly and separate the phases overnight. The molar concentration of APB in the solution is reported as the number of moles of APB per kilogram of polyamine / polyphosphate mixture (i.e., a solution of 1 M APB is reported as 273.1 g of APB added to 1 kg of 7.5% polyamine / 22.5% polyphosphate). Separate the dilute polymer-poor phase of the aggregate from the viscous polymer-rich phase. Incorporate the additive into the aggregate by first adding the solid additive to a scintillation bottle and then pipetting an appropriate amount of the aggregate. After heating in a 70°C oven for 1 hour, the mixture is then vortexed at 3000 rpm.

[0074] Coating preparation

[0075] The PET film was adhered to the glass plate with tape and stretched taut, then corona treated (BD-20C, Electro-technical Products, Inc., Chicago, IL). A 1 wt% PEI undercoat was then applied using a 2-mil gap bird bar (wet thickness 25.4 µm, Gardco AP-B5358, Paul N. Gardner Company, Pompano Beach, FL). The entire plate / coated PET assembly was then dried in a 70°C oven for 20 minutes. The aggregate mixture was then applied to the surface using the same bird bar applicator with either a 2-mil or 1-mil gap. The coating was allowed to dry for one hour before testing or applying a topcoat. Crosslinking agents and other topcoats were applied via spraying using a Yatich spray gun (Colorado Springs, CO) and dried before testing.

[0076] The coating weight was measured by weighing tare weights of 1” diameter PET discs (from a hammer-driven puncher, McMaster-Carr, Elmhurst, IL). The weight of individual 1” diameter coated PET discs was then obtained to determine the coating weight, in grams per m². 2 (gsm). The thickness of coated PET was measured using the Mitutoyo Digimatic Indicator (Aurora, IL), but this measurement is far less reliable than the gsm value.

[0077] UL-94 VTM (ASTM D4804-19) Sample Method

[0078] Samples were prepared according to ASTM D4804-19.9, the standard test method for determining the flammability of non-rigid solid plastics. A 20 cm × 5 cm coated PET sample was wound around a 13 mm diameter rod, and the lower end of the vertically suspended sample was exposed to a 20 mm methane flame for two 3-second applications. The afterflame was recorded as the time the sample remained ignited after the flame was removed.

[0079] Place a cotton ball under the suspended sample to monitor for any molten droplets. For the best rating (VTM-0), the afterflame of the sample must be ≤10 seconds, the cotton must not be ignited, and the flame must not extend the entire length of the sample. The VTM-1 rating can be achieved under the same ignition and consumption conditions, but the afterflame time must not exceed 30 seconds. Finally, an unrated sample indicates that the entire sample was consumed by the flame, and the cotton was ignited by burning particles or droplets.

[0080] Small flame test

[0081] A substantially flat sample, including a front and a back side, is provided. The sample is then attached to an adhesive component with its back side facing down. The adhesive component is then also adhered to a combustible layer having a front and a back side. The adhesive component contacts the back side of the sample 102 and the front side of the combustible layer. The sample, the adhesive component, and the combustible layer together constitute a sample construction. The sample construction is then attached to a frame. At least a portion of the sample construction is attached to the frame, and at least a portion is not attached to the frame. The sample construction is then exposed to a flame source perpendicular to the front side of the sample.

[0082] In one embodiment, the sample is typically a laminated structure. In another embodiment, it is a label material. The sample is cut or pressed into a substantially circular shape and has a diameter of about 0.5 inches to about 1.5 inches.

[0083] In one embodiment, the adhesive can be any adhesive. In other embodiments, the adhesive is a pressure-sensitive adhesive. In one embodiment, the combustible layer is made of filter paper. In this or another embodiment, the combustible layer is made of cellulose. In a specific example, combustible layer 106 is Whatman® paper filter #3 (Cytiva Marlborough, MA, USA). The combustible layer is cut or pressed into a substantially circular shape and has a diameter of about 0.25 inches to about 1.25 inches.

[0084] In an exemplary embodiment, the frame is aluminum, but can be any metal or alloy with a melting point above 400°C. The frame includes at least one hole, and in an exemplary embodiment, the hole is substantially circular. The diameter of the at least one hole is smaller than the diameter of the sample and the combustible layer. In an exemplary embodiment, the diameter is from about 0.25 inches to about 0.75 inches. Furthermore, in an exemplary embodiment, the ratio of the diameter of the at least one hole to the diameter of the sample is from about 1:6 to about 2:3, and the ratio of the diameter of the at least one hole to the diameter of the combustible layer is from about 1:5 to about 1:1. The at least one hole, the sample, and the combustible layer, all of which are circular, are also concentric with respect to each other. In one embodiment, the flame source is a flame jet. In one exemplary embodiment, the flame source is applied to the sample for about 1 second to about 3 seconds. In another embodiment, the flame source is applied to the sample for about 2 seconds.

[0085] Furthermore, the system used for testing may include a timer operably connected to a switch and a solenoid. The switch is then operably connected to a flame source (in this case, a blowtorch), while the solenoid is operably connected to a gate. The timer is set to a value in seconds. This value will trigger the switch before the start of the time interval from the start of combustion at the flame source. The gate can then be activated by the solenoid to expose the sample to be tested. When the timer reaches its value, the switch is operable to shut off the flame source, while the solenoid moves the gate back to its initial position.

[0086] An exemplary method includes providing a substantially flat sample including a front and a back; adhering the sample to a substantially flat combustible layer including a front and a back with an adhesive, and adhering the sample to the back of the sample at the front of the combustible layer to create a sample configuration; attaching the sample configuration to a frame, wherein at least a portion of the sample is attached to the frame and at least a portion is not attached to the frame; exposing the sample configuration to a flame source substantially perpendicular to the front of the sample for a period of time; removing the flame source; inspecting the label material for fire damage; and inspecting the back of the combustible material for fire damage.

[0087] One exemplary implementation describes using a hammer-driven punch to punch out 1” diameter circular samples of coated PET and PSA. A ¾” diameter circular sample of filter paper (Whatman Filter #3, 387 µm, purchased from VWR) is punched out using a hand punch. PSA is applied to the coated surface of the PET and the release liner is removed. The PSA is then adhered to the filter paper and the system is mounted in a sample holder. The sample holder is positioned with the center of the sample circular sample exposed to the tip of a flame. The flame exposure time (2.0 seconds) is automated using a digital timer provided by Avery Dennison.

[0088] Example 1—Basic Formulation PVAm / APP / APB Aggregates

[0089] A base formulation of 7.5% PVAm / 22.5% APP / 0.5 M APB was prepared as the starting point for further experiments and is represented as Example 1. The individual cohesive coating was tacky and had a VTM-1 rating in the UL-94 flame test.

[0090] Example 2—Basic + THPC

[0091] Adding 1% THPC as a topcoat (via spray deposition) achieves a non-sticky coating and improved flame performance. The crosslinked PET coating produces a VTM-0 rating with an average afterflame of approximately 4.5 seconds. The results are shown in Table 1 below. Further improvements were made to the base formulation, including changes to the topcoat and the incorporation of known flame-retardant additives into the aggregate, to further explore ways to improve the flame performance of the coated PET.

[0092] Example 3—VMT

[0093] It was hypothesized that incorporating vermiculite clay (VMT) into the THPC crosslinking solution could improve flame performance. Unfortunately, this was not the case. Therefore, it was further hypothesized that adding a clay layer after the crosslinking agent deposition could further improve the flame performance of the coating while maintaining the reduction in tackiness. Thus, Example 3 was prepared by subsequently spraying a 1% VMT solution onto the dried crosslinked coating. This produced a non-tacky, hazy brown coating. However, as shown in Table 1 below, adding VMT as a topcoat resulted in deteriorated flame performance (VTM-1).

[0094] Example 4—GA Crosslinking

[0095] Other crosslinking agents were explored as alternatives to THPC, including glutaraldehyde (GA) and divinyl sulfone (DVS), as they have proven successful in crosslinking other polyamines. Even with variations in concentration and curing temperature, DVS did not reduce the tackiness of the aggregated coating. The purpose of crosslinking agents is to provide a reduction in tackiness while contributing to improved flame performance. Since DVS failed to reduce coating tackiness, focus shifted to GA as a crosslinking agent.

[0096] After applying 1% GA, the tackiness decreased, but the afterflame time exceeded 30 seconds in the UL-94 flame test, resulting in an unrated VTM rating, as shown in Example 4 in Table 1. This confirms that THPC is an ideal crosslinking agent because it both reduces tackiness and improves the flame-retardant behavior of the coating.

[0097] Examples 5, 6 and 7—Fire Resistant (FR) Additives

[0098] Attempts to incorporate additional expansive components into the aggregates have revealed that guanidine hydrochloride (a common FR foaming agent) does not significantly improve the flame performance of the coating, as now shown. However, other additives (carbon sources and / or acid sources) may contribute to the expansion behavior of the film.

[0099] Pentaerythritol (PER, char accelerator) as Example 5, diammonium hydrogen phosphate (acid source) as Example 6, and urea (foaming agent) as Example 7 were each independently studied as agglomerate additives to improve the flame performance of agglomerate coatings. All additives were added to the agglomerate at a concentration of 5% by weight (approximately 10% dry basis) in the wet agglomerate. The combination of ammonium phosphate and urea produced a transparent, viscous film without significantly improving flame performance. Compared to the pure agglomerate coating, the addition of PER produced an opaque, rigid coating with slightly lower viscousness and improved flame performance. At this point, the opacity of the coating excludes PER as a viable FR additive, but it has the potential to be incorporated into the current "optimal" agglomerate system to improve char formation and flame performance.

[0100] Comparison of examples A and B

[0101] Comparative Example A was pure PET, while Comparative Example B was a commercially available FR film or control coating of unknown composition.

[0102] Table 1—UL-94 Test Results

[0103]

[0104] Examples 8 and 9—Wet-Wet Processing and Wet-Dry Processing

[0105] With the addition of a topcoat improving the flame properties of coated PET, determining the optimal processing method is crucial. Spray coating has been identified as a highly effective way to apply the topcoat to coated PET (compared to dip coating). Therefore, determining the feasibility of "wet-to-wet" versus "wet-to-dry" processing is essential.

[0106] In the wet-dry process, the primed PET is coated with a cohesive and allowed to dry completely in an oven at 70°C (approximately 30 minutes), followed by the application of a topcoat by spraying. This is shown in Table 2 as Example 8.

[0107] In the wet-wet process, prior to spraying, the coated PET is placed in the oven for 5 minutes for partial drying to promote diffusion of the topcoat into the aggregate coating. This is shown in Table 2 as Example 9.

[0108] As shown in Table 2, the wet-to-wet topcoat application method did not significantly improve the flame performance of THPC-crosslinked PVAm / APP / APB. This is likely because the pressure of the liquid spraying damaged the coating, leading to inhomogeneity. This, along with ease of production, is why the wet-to-dry process was chosen as the topcoat application method.

[0109] Table 2

[0110]

[0111] Examples 10 to 13—Changes in the basic cohesive formulation

[0112] Compared to the control coating, the THPC-crosslinked PVAm / APP / APB coating, processed using a wet-dry method, produced the most promising combustion results, with a short afterflame time and a VTM-0 rating. However, further modifications to the coating system are possible to further improve coating durability and flame performance.

[0113] Specifically, to reduce coating crystallization, boric acid was proposed and incorporated into the base aggregate at different weight ratios. Finally, the coating weight and thickness of each coating were reported to ensure that the coatings met given targets.

[0114] Boric acid was added to PVAm / APP / 0.5 M APB at a ratio of 4:5 wt% in Example 10 and 1:5 wt% (boric acid:APB) in Example 11 to reduce the crystallinity of the resulting coating. It was found that 1:5 wt% exhibited better agglomerate formation and improved flame performance (VTM-0) compared to 4:5 wt% (VTM1), as shown in Table 3. However, incorporating boric acid into the agglomerates did not result in a significant reduction in crystallinity. Boric acid was also incorporated as a topcoat into the PVAm / APP / APB agglomerates, but it did not prevent crystallization.

[0115] Poly(allylamine) hydrochloride (PAAm) was used instead of poly(ethyleneamine) at the same concentration to compare the properties of polyamines and aggregate formation, differences in coating crystallinity, and flame performance. The resulting PAAm / APP / 0.5 M APB aggregates were more viscous than their PVAm counterparts, resulting in extremely brittle coatings. However, the PAAm / APP / APB aggregates were non-viscous, had no crystallization issues, and exhibited excellent flame performance, with the pure aggregates producing a VTM-0 rating. To adjust viscosity and brittleness, the APB concentration was reduced to 0.25 M, which made application easier and produced non-viscous coatings with equally good flame performance, as shown in Table 3 as Example 12.

[0116] Given the promising results shown by the PAAm / APP / APB formulation, combinations of different ratios (1:1, 1:2, 2:1) of PAAm and PVAm at a total concentration of 7.5 wt% were evaluated. Among the different ratios, the 2:1 PVAm:PAAm system was the only one exhibiting significant phase separation. The polymer-rich phase was less viscous compared to previously successful aggregates, suggesting that less material may be present in the solution. As shown in Table 3 as Example 13, the resulting film had a significantly lower coating weight and worse flame performance than the PAAm / APP / APB formulation. Even with high coating weights, variations in APB concentration, and crosslinking, the flame performance of the coating did not improve.

[0117] Table 3 - UL-94 test results for different base formulations

[0118]

[0119] Examples 14 and 15—Improved Aggregates

[0120] After evaluating the flame performance of various improved cohesive formulations, PAAm / APP / 0.25 M APB was determined to have the best flame performance and will be considered the "base formulation" for further advancement. As a way to standardize and simultaneously reduce the coating weight and thickness of these films, a 1-mil gap (Example 14) was used to apply the cohesive, compared to a 2-mil gap (Example 15). Similar to the PVAm / APP / APB system, various topcoats and additives were evaluated with the new PAAm / APP / APB formulation to optimize coating performance.

[0121] Examples 16 to 20—Changes in the topcoat

[0122] In the previous base formulation (PVAm / APP / APB), the addition of THPC crosslinking agent as a topcoat resulted in a significant improvement in the flame performance of the coating. THPC is expected to have the same effect on the new base formulation PAAm / APP / APB. Although the reduction in coating weight and film thickness due to the thinner rod gap slightly reduced the flame performance of the pure cohesive coating, the addition of 1% THPC as a topcoat produced excellent flame performance at a similar coating weight and thickness to the pure cohesive coating, as shown in Table 4 below. PAAm / APP / APB (Example 16) crosslinked with THPC at a 1 mil gap exhibited a very short afterflame time (approximately 1.5 seconds each), producing a VTM-0 rating.

[0123] The same condensate deposited using a 2-mil gap (Example 17) did indeed exhibit slightly better flame performance, but the large difference in film thickness made it difficult to compare with the performance of the pure condensate. The PAAm / APP / APB crosslinked with THPC was the best-performing coating to date, with an afterflame time almost identical to the control coating, a thickness of only 13 μm, and a coating weight of 22 gsm.

[0124] Initially, NaCl and CaCl2 were incorporated into the agglomerates as additives. After the addition of NaCl failed to improve the flame performance of the coating, and CaCl2 achieved complexation of the agglomerate components, calcium salts were explored as alternative topcoats for THPC. At the same concentration (1 wt%), CaCl2-topcoated agglomerates exhibited improved flame performance compared to pure agglomerates. Similar to the pure agglomerates and THPC systems, the thinner coating with a 1-mil gap (Example 18) exhibited slightly worse flame performance compared to the 2-mil gap coating (Example 19). However, using smaller gaps resulted in more consistent coating weight, thickness, and flame performance, simplifying the comparison of coating performance. It is evident from these results that the addition of CaCl2 contributes to the flame performance of the coating, as indicated by the VTM-0 rating, but the THPC-crosslinked agglomerate coating still outperforms the CaCl2 topcoat at nearly the same coating weight and film thickness.

[0125] Since both THPC and CaCl2 improve the flame performance of cohesive coatings, it was hypothesized that a combination of these two components applied as a single topcoat could further improve the flame performance. However, as shown in Table 4 as Example 20, adding THPC+CaCl2 at a 1:1 weight ratio as a topcoat did not perform as well as a topcoat containing only the individual components. Even at different ratios (1:2, 1:10), adding a second component to the topcoat did not result in improved flame performance. Finally, applying THPC and CaCl2 in subsequent steps, producing a total of three layers (excluding the undercoat), did not significantly improve the coating performance.

[0126] Table 4 - UL-94 test results of PAAm / APP / 0.25 M APB base formulation with topcoat

[0127]

[0128] Examples 21 to 24—Agglomerate Additives

[0129] The THPC-crosslinked PAAm / APP / APB coating exhibited excellent flame performance in the UL-94 test, but the coating itself was somewhat brittle and prone to small cracking. While this did not change the fire-retardant properties of the coating, it led to other issues with the appearance of the final product. To reduce the brittleness / shrinkage of the coating, flame-retardant fillers such as poly(ethylene oxide) (PEO) (Example 21), montmorillonite clay (MMT) (Example 22), and sodium silicate (Example 23) were each independently incorporated into the base coagulant (0.25 M APB) at a concentration of 1% by weight. Both PEO and MMT were well integrated into the coagulant, and all three coagulant coatings were transparent and tacky. As shown in Table 5 below, the formulation without additives achieved a VTM-0 rating, but compared to PAAm / APP / APB, adding 1% MMT to the coagulant resulted in the best flame performance and a significantly lower coating weight.

[0130] Then, in Example 24, THPC was applied to the promising improved formulation (PAAm / APP / 0.25 M APB+MMT). Although the combination achieved a VTM-0 rating, it still could not compare with the best performing formulation (i.e., THPC-crosslinked PAAm / APP / 0.25 M APB, Examples 16 and 17).

[0131] Table 5 - UL-94 for PAAm / APP / 0.25 M APB formulations with various additives

[0132]

[0133] Test results of the best performing formulation

[0134] The performance of the control coating was evaluated using a microflame test compared to the best-performing formulation to date. For example... Figure 2As shown, under 2.0 seconds of flame exposure, two of the three Comparative Example B samples (column a) burned through completely, while all the best-performing cohesive formulations remained intact. Although all formulations appeared to have similar performance in the micro-test, the pure PAAm / APP / APB cohesive (1 mil) (column b) in Example 14 appeared to be the most successful, with the smallest burn area on the back side of the sample. The cohesive coating with a 1% THPC topcoat in Example 16 (column c) and the cohesive coating with a 1% CaCl2 topcoat in Example 18 (column d) exhibited similar flame performance, with the CaCl2 topcoat having a slightly darker burn area on the back side. Finally, the incorporation of MMT into the PAAm / APP / 0.25 M APB cohesive followed by a 1% THPC topcoat in Example 24 (column e) achieved similar performance compared to either the 1% THPC or 1% CaCl2 topcoat. However, the carbonization formation of this coating is smoother compared to other cohesive coatings, which may be due to the clay additives forming a ceramic carbonization barrier that prevents the appearance of expanded bubbles observed in other cohesive systems.

[0135] Testing the Importance of Condensed Systems

[0136] To determine the importance of the active components in the aggregate phase, the flame performance of the dried aggregates and individual aggregate components was evaluated as solids suspended in a solvent. Samples of PAAm / APP / APB aggregates were placed in a 70°C oven for 48 hours to ensure complete drying. The dried aggregates were then ground into powder and added to 20% by weight of polystyrene (PS) in methyl ethyl ketone (MEK) at different concentrations (30 wt%, 50 wt%, and 60 wt%). The solution was then cast onto PET by scraping and dried in a 70°C oven to evaporate the solvent, leaving only the dried aggregate solids and polystyrene. PAAm, APP, and APB were added as solids to the same PS / MEK mixture at the same weight ratios (7.5 wt%, 22.5 wt%, and 0.5 M, respectively) to evaluate the performance of the bulk component compared to the components in the aggregates. The coating process was identical to that of the dried aggregate system, and the coatings for both systems were transparent with small particles uniformly distributed throughout. Table 6 summarizes the UL-94 flame test results for the dried aggregate coating and the bulk aggregate component coating. The length of the dried cohesive coating burned and melted and dripped during the first flame exposure, causing the cotton blanket to ignite, which is considered unrated at all concentrations. Similarly, coatings containing bulk cohesive components melted and dripped, resulting in an unrated VTM rating. While the cohesive phase enables molecular interactions to produce coatings that achieve ideal flame behavior, the solvent system requires non-reactive components (i.e., polystyrene) that contribute to the flammability of the material. For cohesive systems, all components present in the film positively contribute to the flame retardancy of the substrate.

[0137] Table 6. UL-94 test results of dried aggregates and aggregate components in PS / MEK.

[0138]

[0139] Further improvements can be made by reducing the brittleness of the PAAm / APP / APB coating, which can be achieved by reducing the total solids in the aggregates or by depositing less material through thinner rod gaps. To further improve coating uniformity and ease of fabrication, alternative deposition methods for THPC crosslinkers, such as blade coating, can be explored. However, the viscosity of THPC alone is insufficient for effective blade coating; therefore, thickeners such as PEO, carboxymethyl cellulose, or glass frit must be incorporated into the THPC solution to successfully apply the topcoat.

[0140] All definitions defined and used herein should be understood to take precedence over dictionary definitions, definitions in incorporated documents by reference, and / or the general meaning of the terms they define.

[0141] Unless explicitly stated otherwise, nouns without quantifiers as used herein in the specification and claims shall be understood to mean “at least one / one / one of”. The phrase “and / or” (if any) as used herein in the specification and claims shall be understood to mean “any one or both” of the elements in such a combination, i.e., elements that exist together in some cases and separately in others. Multiple elements listed with “and / or” shall be interpreted in the same manner, i.e., “one or more” of the elements in such a combination. Other elements may optionally be present in addition to those specifically indicated by the “and / or” clause, whether related to or unrelated to those specifically indicated. Thus, as a non-limiting example, when used in conjunction with open-ended language such as “comprising,” a reference to “A and / or B” may in one embodiment refer only to A (optionally including elements other than B); in another embodiment, it may refer only to B (optionally including elements other than A); in yet another embodiment, it may refer to both A and B (optionally including other elements); and so on. As used herein in the specification and claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when items in a separate list are separated, “or” or “and / or” should be understood to be inclusive, that is, including multiple elements or at least one of the elements in the list, but also including more than one, and optionally including other items not listed. Only when the opposite terms are explicitly indicated, such as “only one of…” or “exact one of…”, or when used in a claim, “consisting of…”, will refer to including multiple elements or exactly one of the elements in the list. Generally, when preceded by exclusive terms such as “any one,” “one of…,” “only one of…” or “exact one of…”, the term “or” as used herein should be understood only to indicate an exclusive alternative (i.e., “one or the other, but not both”). When used in a claim, “consisting substantially of…” should have its ordinary meaning as used in the field of patent law.

[0142] As used herein in the specification and claims, the phrase "at least one" when referring to a list of one or more elements should be understood to mean at least one element selected from any one or more elements in the list, but does not necessarily include all elements specifically listed in the list and at least one of each element, and does not exclude any combination of elements in the list. This definition also allows for the optional presence of elements other than those specifically indicated in the list of elements referred to in the phrase "at least one," whether related to or unrelated to those specifically indicated elements. Therefore, as a non-limiting example, "at least one of A and B" (or equivalently, "at least one of A or B", or equivalently, "at least one of A and / or B") in one embodiment may refer to at least one A, optionally including more than one A, with no B (and optionally including elements other than B); in another embodiment, it may refer to at least one B, optionally including more than one B, with no A (and optionally including elements other than A); in yet another embodiment, it may refer to at least one A, optionally including more than one A, and at least one B, optionally including more than one B (and optionally including other elements); and so on.

[0143] The implementation scheme refers to the method or embodiment of the content of this disclosure. References to "implementation scheme," "one implementation scheme," "some implementation schemes," "a specific implementation scheme," or "other implementation schemes," etc., in the specification mean that a specific feature, structure, or characteristic described in connection with the implementation scheme is included in at least some embodiments of the invention, but not necessarily in all embodiments of the invention. The various appearances of "implementation scheme," "one implementation scheme," "some implementation schemes," "a specific implementation scheme," or "other implementation schemes," etc., do not necessarily all refer to the same implementation scheme.

[0144] If this specification states that "may," "may," or "can" include a component, feature, structure, or characteristic, it is not necessary to include that particular component, feature, structure, or characteristic. If the specification or claims refer to an element without a quantifier, this does not imply the existence of only one such element. If the specification or claims refer to an "additional" element, this does not preclude the existence of more than one additional element.

[0145] As used herein, including as in the embodiments, unless otherwise expressly stated, all numbers are to be interpreted as if they begin with the words “about” or “approximately”, even if the term is not explicitly stated. When describing size and / or location, the phrase “about” or “approximately” may be used to indicate that the described value and / or location is within a reasonably expected range of value and / or location. For example, numerical values ​​may have values ​​of + / -0.0%, + / -1%, + / -2%, + / -5%, + / -10%, etc., of the value (or range of values). Any numerical range described herein is intended to include all subranges contained herein.

[0146] Furthermore, any method of performing the contents of this disclosure may be performed in a different order than those described herein. Therefore, unless explicitly stated otherwise, the order of the methods should not be construed as limiting. It will be appreciated that performing some steps of the method in a different order can achieve similar results.

[0147] In the claims and in the foregoing description, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “constituting,” etc., shall be understood as open-ended, that is, meaning including but not limited to. As set forth in the Patent Examination Procedure Manual of the U.S. Patent Office, only the transitional phrases “constituting of” and “constituting substantially of” shall be closed or semi-closed transitional phrases, respectively.

[0148] In the foregoing description, certain terms have been used for the purpose of brevity, clarity, and understanding. Since such terms are used for descriptive purposes and are intended to be interpreted broadly, they do not imply unnecessary limitations beyond the requirements of the prior art.

[0149] Furthermore, the descriptions and illustrations of various embodiments of this disclosure are exemplary, and this disclosure is not limited to the exact details shown or described.

Claims

1. A composition comprising: about 0.1 wt% to about 20 wt% of at least one polycation; about 0.1 wt% to about 50 wt% of at least one polyanion; and about 0.1% to about 35 wt% of at least one plasticizing salt.

2. The composition of claim 1, wherein at least one of the polycations is a polyvinylamine, a polyallylamine hydrochloride, and a combination of polyvinylamine and polyallylamine hydrochloride.

3. The composition of claim 2, wherein the weight percent of polyvinylamine and polyallylamine are equal.

4. The composition of claim 2, wherein the weight percent of polyvinylamine is about 0.1 wt% to about 20 wt%.

5. The composition of claim 2, wherein the weight percent of poly(allylamine) is about 0.1 wt% to about 20 wt%.

6. The composition of claim 1, wherein the at least one polyanion comprises polyammonium phosphate.

7. The composition of claim 1, wherein the at least one plasticizing salt comprises ammonium pentaborate tetrahydrate.

8. The composition of claim 1, further comprising about 0.1 wt% to about 4 wt% of a crosslinking agent.

9. The composition of claim 8, wherein the crosslinking agent comprises tetramethylol chloride .

10. The composition of claim 1, further comprising about 0.1 wt% to about 30 wt% of boric acid.

11. The composition of claim 1, further comprising about 0.1 wt% to about 3 wt% of calcium chloride.

12. The composition of claim 1, further comprising at least about 0.1 wt% to about 15 wt% of a charring promoter.

13. The composition of claim 12, wherein the charring promoter is pentaerythritol.

14. A method for manufacturing a heat resistant, flame retardant multilayer laminate comprising: providing a polymeric or paper facestock layer; providing a polymeric adhesive layer; providing a polymeric topcoat layer; depositing a heat resistant, flame retardant composition on the polymeric topcoat layer, wherein the composition comprises: about 0.1 wt% to about 20 wt% of at least one polycation, about 0.1 wt% to about 50 wt% of at least one polyanion, and about 0.1% to about 35 wt% of at least one plasticizing salt; and sandwiching the facestock layer between the topcoat layer and the adhesive layer.

15. The method of claim 14, wherein the depositing comprises spraying.

16. The method of claim 14, wherein at least one of the polycations in the composition is a polyvinylamine, a polyallylamine hydrochloride, and a mixture thereof.

17. The method of claim 14, wherein the at least one polyanion in the composition comprises polyammonium phosphate.

18. The method of claim 14, wherein the at least one plasticizing salt in the composition comprises ammonium pentaborate tetrahydrate.

19. The method of claim 14, wherein the composition further comprises about 0.1 wt% to about 4 wt% of a crosslinking agent.

20. The method of claim 14, wherein the composition further comprises tetra- methylol chloroformal .

21. A method for manufacturing a heat resistant, flame retardant multilayer laminate comprising: depositing a heat resistant, flame retardant composition on a polymeric topcoat layer positioned on a polymeric or paper facestock layer, wherein the composition comprises: about 0.1 wt% to about 20 wt% of at least one polycation, about 0.1 wt% to about 50 wt% of at least one polyanion, and about 0.1% to about 35 wt% of at least one plasticizing salt. about 0.1 wt% to about 20 wt% of at least one polycation, about 0.1 wt% to about 50 wt% of at least one polyanion, and about 0.1% to about 35 wt% of at least one plasticizing salt; and sandwiching the facestock layer between the topcoat layer and the adhesive layer.

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