Hybrid expandable compositions and uses thereof

Abstract

Hybrid intumescent compositions are disclosed that provide improved expansion and loft properties. The hybrid intumescent compositions are particularly useful for providing thermal insulation and / or cushioning to substrates.

Description

[Technical Field]

[0001] The present invention relates to hybrid expandable compositions that provide improved expansion and loft properties. In particular, the present invention includes compositions for use in providing thermal insulation and / or cushioning to substrates and methods for making said compositions. [Background technology]

[0002] There is a need for biodegradable and / or compostable packaging and containers. One such packaging includes a cellulose-based substrate made from renewable materials that can be recycled, composted, and / or biodegraded. The package is made by bonding two cellulose substrates together, with multiple voids between the two cellulose substrates. These alternative packages have the disadvantage of lower insulation and structural integrity compared to plastic packaging. Handling or bending the package compresses the voids, destroying the insulation in the compressed areas. Various technologies are described in U.S. Patent Nos. 9,580,629, 8,747,603, 9,273,230, 9,657,200, 2014 / 0087109, 2017 / 0130399, 2017 / 0130058, 2016 / 0263876, and WO2019 / 018523. Some techniques improve structural integrity by including additional or thicker substrates or by enhancing air gap insulation. Such additions increase the carbon footprint or increase the overall cost of the package. Effective insulation and structural integrity are needed in the art to produce environmentally and economically sound packages and containers. Summary of the Invention [Means for solving the problem]

[0003] The present invention relates to hybrid expandable compositions that provide improved expansion and loft properties.

[0004] In a first embodiment of the present invention, a hybrid expandable composition having improved thermal insulation and cushioning properties is provided, comprising: (i) a binder system that is a mixture of an emulsion polymer binder having a Tg range of about -40°C to about 60°C and (ii) a starch or dextrin; a plurality of pre-expanded or expandable microspheres; and a water-soluble salt.

[0005] Another embodiment of the present invention provides a hybrid expandable composition characterized by having a closed cell structure and an open cell structure, prepared from a hybrid expandable composition comprising: about 30 to about 80 wt. % of a hybrid binder system mixture; about 1 to about 15 wt. % of a plurality of microspheres; about 0.1 to about 5 wt. % of a water-soluble salt; and up to about 5 wt. % of an additive.

[0006] Yet another embodiment of the present invention comprises: (i) about 30 to about 80 wt. % of a binder system which is a mixture of (i) an emulsion polymer binder having a Tg range of about -40°C to about 60°C and (ii) starch or dextrin; (ii) about 1 to about 15 wt. % of a plurality of microspheres; (iv) about 0.1 to about 5 wt. % of a water-soluble salt; and (v) up to about 5% by weight of additives preparing a hybrid expandable composition comprising: applying the hybrid expandable composition onto a substrate; Rapidly heating the hybrid expandable composition; A method of forming a hybrid expandable material is provided that includes cooling the hybrid expandable composition to harden the hybrid expandable material. [Brief explanation of the drawings]

[0007] [Figure 1A] FIG. 1A is a side view of unexpanded Sample 3. [Figure 1B] FIG. 1B is a side view of expanded Sample 3. [Figure 2]FIG. 2 is a graph of force (g) versus indentation (mm) from the elasticity test of Sample 3. [Figure 3] FIG. 3 shows the peak force of each elastic force test for Sample 3. [Figure 4A] FIG. 4A is a top view photograph of an expanded comparative sample containing 20% ​​microspheres. [Figure 4B] FIG. 4B is a top view photograph of expanded sample 3. [Figure 5A] FIG. 5A is a side view of an expanded comparative sample containing 20% ​​microspheres. [Figure 5B] FIG. 5B is a side view of expanded sample 3. DETAILED DESCRIPTION OF THE INVENTION

[0008] (Detailed Description of the Invention) Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. In case of conflict, the present specification, including definitions, will prevail. Preferred methods and materials are described below, but methods and materials similar or equivalent to those described herein can be used to practice or test this disclosure. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. The materials, methods, and examples disclosed herein are for illustrative purposes only and are not intended to be limiting.

[0009] As used herein, the term "comprise" can include "consisting of" and "consisting essentially of" embodiments. The terms "comprise(s)," "include(s)," "having," "has," "can," "contain(s)," and variations thereof, as used herein, are intended to be open-ended transitional phrases, terms, or words that require the presence of the specified ingredients / steps and permit the presence of others. However, such descriptions should also be construed as describing the composition or process as "consisting of" and "consisting essentially of" the listed ingredients / steps, whereby only the specified ingredients / steps are permitted to be present along with impurities that may result therefrom, and to the exclusion of other ingredients / steps.

[0010] Numerical values ​​herein, particularly with respect to polymers or polymer compositions, represent average values ​​for compositions that may include individual polymers of different properties. Furthermore, unless otherwise specified, numerical values ​​should be understood to include numerical values ​​that are the same when converted to the same number of significant figures, and numerical values ​​that differ from the stated value by no more than experimental error of conventional measurement techniques of the type described herein to determine the value.

[0011] All ranges disclosed herein are inclusive of the recited endpoints and are independently combinable (e.g., the range "from 2 to 10" includes the endpoints 2 and 10, and all intermediate values). The endpoints of the ranges and any values ​​disclosed herein are not limited to the exact range or value. These ranges and / or values ​​are sufficiently imprecise to include values ​​that are close to or approximate the range. As used herein, approximation language may be applied to modify any quantitative expression that can change without resulting in a change in the associated basic function. Thus, values ​​modified by terms such as "about" may, in some cases, not be limited to the exact value specified. In at least some instances, approximation language may correspond to the precision of the device used to measure the value. The modifier "about" should be considered to disclose a range defined by the absolute values ​​of the two endpoints. For example, the phrase "from about 2 to about 4" also discloses the range "from 2 to 4." The term "about" may refer to plus or minus 10% of the indicated numerical value. For example, "about 10%" can indicate a range of 9% to 11, and "about 1" can mean 0.9 to 1.1. Other meanings of "about" will be apparent from the context, such as rounding; for example, "about 1" can mean 0.5 to 1.4.

[0012] The present invention provides a hybrid intumescent composition that, once expanded, provides insulating properties and structural integrity for use. The hybrid intumescent compositions described herein can be useful on recyclable, compostable, or biodegradable substrates. The hybrid intumescent compositions described herein require fewer synthetic materials than traditional packaging, which requires plastic bubble wrap to provide cushioning and insulation. The end result is a less expensive, more environmentally friendly product. Hybrid intumescent compositions useful herein include paper products for consumer use, such as packaging, containers, envelopes, and boxes.

[0013] The present invention is based on the discovery of a hybrid expandable composition for use in manufacturing thermal insulation and protective products based on a hybrid system of open-cell and closed-cell foams. When formed together, the combination of open-cell and closed-cell foams provides structural integrity and protective insulating properties to products with a low carbon footprint. Additionally, the hybrid foam allows the product to use thinner (lower basis weight) substrates, further reducing the carbon footprint.

[0014] In a first embodiment, the hybrid expandable composition comprises: (i) an emulsion polymer binder having a Tg range of about -40°C to about 60°C and (ii) a binder system that is a mixture of starch or dextrin; a plurality of pre-expanded or expandable microspheres; and a water-soluble salt. The composition may further comprise one or more antifoaming agents, plasticizers, preservatives, surfactants, rheology modifiers, fillers, pigments, dyes, stabilizers, polyvinyl alcohol, wetting agents, and mixtures thereof. Other materials that do not adversely affect the composition and its insulating properties can be used as needed.

[0015] Various combinations of (i) emulsion polymer binders having a Tg range of about -40°C to about 60°C and (ii) starches or dextrins can be utilized to form this binder mixture. However, the binders may be used at temperatures below 25°C, 0.1 s -1 Shear viscosity greater than 10 Pas measured at 25°C, 100 s using Brookfield -1 The viscosity should be less than about 2 Pas as measured at 1000 W. This viscosity range improves shelf life and coatability.

[0016] The emulsion polymer may contain any desired polymeric components, including vinyl acetate ethylene dispersions, polyvinyl acetate, polyvinyl acetate polyvinyl alcohol, dextrin-stabilized polyvinyl acetate, polyvinyl acetate copolymers, vinyl acetate ethylene copolymers, vinyl acrylics, styrene acrylics, acrylics, styrene butyl rubbers, polyurethanes, starches, and mixtures thereof. Particularly preferred emulsion polymer components are vinyl acetate ethylene dispersions, and polyvinyl acetate and starch. Preferably, the emulsion polymer is stabilized with a hydrophilic protective colloid. The emulsion polymer has a Tg range of about -40°C to about 60°C, preferably about -40°C to about 0°C; most preferably about -35°C to about -5°C.

[0017] The starch or dextrin component can be from about 5 to about 30% by weight, based on the total weight of the hybrid leavening composition.

[0018] Dextrins are typically prepared by heating starch in the presence of acid at temperatures below 150°C, usually under mild hydrolysis conditions (79-120°C for 3 to 8 hours in 0.2-2% H2SO4 or HCl) in a 30-40% suspension. According to the Merck Index (Dextrin Monograph No. 2953, 2006), the solubility range of white dextrins is 5% to 90%. White dextrins have lower water solubility and viscosity than yellow dextrins and British gums. Preferred white dextrins for hybrid bulking compositions have a solubility range of about 25% to about 75%.

[0019] The starch can be native and / or modified. Native starch can be selected from corn, potato, rice, tapioca, or other starch sources. Modified starch is prepared by chemically, physically, or enzymatically modifying certain starches.

[0020] The microspheres can be pre-expanded or expandable microspheres in the hybrid expandable composition. Pre-expanded microspheres are fully expanded and do not require further expansion. Hybrid expandable microspheres useful in the present invention should be capable of expanding in size in the presence of heat and / or radiation energy (e.g., including microwave, infrared, radio frequency, and / or ultrasonic energy). Microspheres useful in the present invention include, for example, thermally expandable polymer microspheres having a hydrocarbon core and a natural, semi-synthetic, or synthetic shell. Preferred expandable microspheres include those with a hydrocarbon core and a polyacrylonitrile and / or polyacrylate shell (such as those sold under the trade name Dualite®) and other similar microspheres (such as those sold under the trade name Expancel®). Hybrid expandable microspheres can have any unexpanded size, including diameters of about 10 microns to about 30 microns. In the presence of heat, the hybrid expandable microspheres of the present invention can increase in diameter by about 3 to about 10 times. That is, the diameter of the hybrid expandable microspheres can be expandable from about 300% of the starting diameter to about 1,000% of the starting diameter, and most desirably, the diameter of the hybrid expandable microspheres can be expandable from about 350% to about 600% of the starting diameter. Upon expansion, the microspheres provide a closed cell foam structure, providing loft to the hybrid expandable composition.

[0021] Hybrid expandable microspheres have a specific temperature at which they begin to expand and a second temperature at which they reach maximum expansion. Different grades of microspheres have different expansion temperatures (Texp) and maximum expansion temperatures (Tmax). For example, one particularly useful microsphere has a Texp of about 80°C and a Tmax of about 120°C, while another useful microsphere has a Texp of about 135°C and a Tmax of about 200°C. While any specific grade of microsphere can be used, the Texp and Tmax of the microspheres should be considered during formulation and processing in the present invention. Desirably, the temperature at which these microspheres begin to expand (Texp) is about 80°C to about 135°C. The temperature at which the microspheres reach maximum expansion (Tmax) is desirably about 120°C to about 200°C. The selection of specific microspheres and their respective Texp and Tmax is not critical to the present invention, but processing temperatures can be varied accordingly.

[0022] The water-soluble salt in the hybrid expandable composition is selected from the group consisting of sodium chloride, potassium chloride, sodium nitrate, potassium nitrate, potassium sulfate, ammonium sulfate, and mixtures thereof. Without being bound by theory, the salt heats the water in the composition more quickly, reducing the time required for the composition to expand. When added, about 0.1 to about 5, preferably about 0.5 to 3 wt. % can be used based on the total weight of the composition.

[0023] The composition may further comprise one or more antifoaming agents, plasticizers, preservatives, surfactants, rheology modifiers, fillers, pigments, dyes, stabilizers, polyvinyl alcohol, wetting agents, and mixtures thereof. Additives including antifoaming agents, plasticizers, preservatives, surfactants, rheology modifiers, fillers, pigments, dyes, stabilizers, polyvinyl alcohol, or wetting agents can be added in amounts up to 5% by weight based on the total weight of the hybrid expandable composition.

[0024] In another embodiment, the hybrid expandable composition comprises: a. about 30 to about 80 weight percent of a binder system; b. about 1 to about 15 wt. % microspheres; c. about 0.1 to about 5 wt. % of a water-soluble salt; and d. Contains up to about 5% by weight of additives.

[0025] Depending on the binder system, the hybrid intumescent composition will adhere to the substrate when wet. Furthermore, the hybrid intumescent composition will maintain adhesion to the substrate upon expansion. While strong adhesion is not required, it is desirable for the composition to remain on the substrate for an extended period of time to provide insulation and cushioning. One skilled in the art can modify the adhesion level to increase or decrease adhesion to a particular substrate.

[0026] A method of forming a hybrid expandable material is also provided, in which forming the hybrid expandable material comprises: a. preparing the hybrid expandable composition; b. applying the hybrid expandable composition onto a substrate; c. Rapidly heating the hybrid expandable composition; d. Cooling the hybrid expandable composition.

[0027] The composition may be prepared immediately prior to molding, or may be prepared in advance and stored until needed.

[0028] The hybrid intumescent composition can be applied to a substrate in any desired configuration, including a series of dots, stripes, waves, checkerboards, any common polyhedral shape with a substantially flat base, and combinations thereof. Additionally, the hybrid intumescent composition can be applied to a first surface in a series of cylinders. If desired, the hybrid intumescent composition can be applied to the entire substrate. Optionally, a second substrate can be applied on top of the hybrid intumescent composition to form a first substrate-intumescent composition-second substrate sandwich configuration. In another embodiment, multiple substrates can be utilized to form multilayer articles to provide enhanced thermal insulation and cushioning. For articles with more than two substrates, the hybrid intumescent composition can be applied in an offset pattern from the previous substrate (the pattern configuration on each substrate is offset from the configuration above and below) to provide strength to the article. The substrate can be a cellulose substrate, wood, or a plastic film with a melting point above about 100°C. Particularly preferred substrates are fiberboard, chipboard, corrugated cardboard, corrugated cardboard inner board, solid bleached board, solid bleached sulfite board, solid unbleached board, white-lined chipboard, kraft paper, kraft board, binder board, and coated paper. Alternatively, the substrate may be oriented polypropylene film, cellophane, polyester film, polypropylene film, polyethylene film, metallized film, compostable polymer film, biodegradable polymer film, or bio-based film. Furthermore, the substrate may be substantially planar or non-planar, such as media typically found in corrugated substrates.

[0029] To expand the hybrid expandable composition, rapid heating, including microwave, infrared, radio frequency, and / or ultrasonic energy heating, is required. Rapid heating creates an open-cell structure from the binder in the expandable composition. When used in the composition, the maximum heating temperature should not be approximately 30°F higher than the Tmax of the hybrid expandable microspheres. Temperatures approximately 30°F higher than Tmax can cause the microspheres to rupture.

[0030] Hybrid expandable compositions are characterized by having both closed and open cell structures upon expansion. The closed cell structure comes from the microspheres, while the open cell structure comes from the binder system. A binder mixture of an emulsion polymer binder and starch or dextrin provides these open cell structures. Without being bound by any particular theory, the rapid heating of the starch or dextrin combined with the space created by the microspheres and the additional elasticity from the emulsion polymer allows the composition to create higher loft, or expansion, of the hybrid expandable system. The combination of both closed and open cell structures results in a synergistic effect of higher expansion. While higher loadings of microspheres may provide similar expansion, loading limitations occur when the binder polymer is unable to fill the gaps between the expanded spheres. Furthermore, such systems become too brittle to provide protective insulation (padding) and cushioning. Systems without microspheres cannot provide significant loft. Additionally, this particular synergistic foaming system provides resilience and maintains closed and open cell structure even when pressure is applied.

[0031] As the hybrid intumescent material cools, the closed and open cell structures harden. During this cooling phase, the height of the substrate can be normalized by applying pressure to the substrate, resulting in a consistent height of the intumescent material across the substrate.

[0032] It has been discovered that the hybrid expandable compositions of the present invention can provide the necessary protective insulation and cushioning for packages and containers. The adhesives and coatings can be applied to a substrate to form the desired packages and containers. The adhesive can be applied continuously or discontinuously to the edges of the substrate to seal the packages and containers. In another embodiment, the adhesive can be selectively applied to non-edge portions to hold the substrates together. The packages and containers can be formed as envelopes, pouches, bags, boxes, cartons, cases, lids, wraps, clamshells, cups, food containers, and the like.

[0033] In one embodiment, a package is formed from the hybrid expandable composition interspersed between two substrates in a non-continuous pattern. For example, an adhesive can be applied to the edge of one substrate to hold the two substrates together and form a planar article. A second, single planar article can then be adhered to three-quarters of the surface with the same or a different adhesive to form a pouch. Alternatively, a single planar article can be folded at one seam and the other two edges sealed together with the same adhesive but with a different adhesive to form a pouch. It is also conceivable to attach a pressure-sensitive adhesive strip to the last remaining edge to seal the package. In one embodiment, the final edge can be formed as a flap with a pressure-sensitive adhesive applied to the flap. The pressure-sensitive adhesive can have a liner cover that can be later removed to close and seal the flap. Planar articles containing the hybrid expandable material can serve as the basis for forming articles including adhesive-applied envelopes, bags, boxes, cartons, cases, lids, wraps, clamshells, cups, and food containers. Alternatively, the articles can be molded first and then expanded using the hybrid expandable composition and adhesive to form the desired article.

[0034] The adhesives described above may also be made from renewable, compostable, or biodegradable materials to further reduce carbon footprint. Both hot melt and water-based adhesives are contemplated, as they can be processed simultaneously with the hybrid intumescent composition. As the hybrid intumescent composition expands during rapid heating, the hot melt and water-based adhesives cure and bond the substrates.

[0035] Due to uneven heating in a domestic microwave oven, some of the expanded foam may not be symmetrical. The height of the "expanded sandwich" can be measured and used as a guide to the degree of expansion. However, height alone cannot be used to determine the degree of expansion of a hybrid composition; other factors such as percent solids, viscosity, expansion rate, foam loss, and foam resilience are used to evaluate the foamed material.

[0036] Foam resilience is a measure of four factors of a foam's ability to recover after repeated compression. These factors are initial compression force, initial foam height, foam height loss (indentation), and the slope of the force decline. Thus, resilience characteristics do not represent a single quantitative number, but rather a four-pronged approach to determining the most resilient expanded foam and its desired values. Foam height is the initial height of the expandable composition after it is rapidly heated and dried. A high initial foam height is desirable. Initial force is the resistance of the foam material to compression. The higher the initial force, the stronger the foam material's resistance to compression. Foam loss is the initial decrease in foam height after repeated compression cycles. Low foam loss is desirable because it indicates good recovery from repeated compression cycles. The slope is obtained from a semi-logarithmic fit of the decrease in peak compression force over a five-cycle resilience test. A low slope indicates that the foam recovers well from repeated compression.

[0037] [Table 1]

[0038] The present invention may be better understood through an analysis of the following examples, which are non-limiting and are intended only to help illustrate the invention. [Example]

[0039] Example 1 - Forming a sample The following samples were made by mixing the ingredients in the following order in a container at room temperature and using an overhead paddle mixer at approximately 300 rpm: water, salt, microspheres, binder system, and then additives, from lowest to highest viscosity. The ingredients for each sample are listed in Table 1.

[0040] [Table 2]

[0041] Example 2 - Sample performance characteristics For each sample, the percent solids, viscosity, expansion rate, slope, initial force, foam height, foam loss, and resilience test cycles were measured and are shown in Table 2. [Table 3]

[0042] The percent solids was determined by weighing approximately 1.0 ml of sample into a pre-weighed dish on an analytical balance and then placing it in an oven at 130° C. for 30 minutes. After drying, the sample was reweighed and the percent solids calculated and reported in Table 2.

[0043] The shear viscosity of the samples was measured at 25 °C with an ARES-Fluid rheometer equipped with 2.5 cm diameter parallel plates. A drop of sample was placed on the geometry, and the gap was set to approximately 0.2 mm so that the liquid sample just filled the gap between the plates. The shear rate sweep was 0.01 s. -1 From the 1000s -1 It is done in 0.1 seconds from the dataset. -1 and 100s -1Two data points were taken and reported in Table 2.

[0044] Foam height is the height of the sample after it has expanded. A known mass of the expandable sample, typically 20–100 milligrams, was placed as a hemispherical dot / drop on a thin glass coverslip and placed directly on the turntable near the top edge of the ring track of a 1 kW domestic microwave oven. This was then heated at full power for 10 seconds. The hemispherical dot expanded to a symmetrical "mushroom cap" or very close to it. Because the freshly expanded foam still contained moisture during expansion, it was left to dry or solidify. A side view of the dried foam was then photographed, referencing the known width. The profile was digitized using image analysis software (ImageJ or Fiji), allowing for the determination of foam height and volume.

[0045] Figure 1 shows a side view of Sample 3. Figure 1A shows the unexpanded wet Sample 1, and Figure 1B shows the expanded and dried Sample 1.

[0046] The expansion ratio is the volume of the expanded dry foam divided by the volume of the liquid sample. As described above, expanded foam dots approximately 4-8 mm in height were formed in a microwave oven using sample sizes of 20-100 milligrams. Because the wet density of the sample was known, the wet volume was calculated, and thus the expansion ratio was obtained. Alternatively, a side profile of the wet drop was photographed and digitized to calculate the wet volume.

[0047] Five elastic force test cycles were performed to measure initial force, foam loss, and slope. These measurements were performed using a parallel platen setup on a Texture Analyzer (model TA.XPlus). A dedicated procedure was programmed in the Texture Analyzer software, and the test was automatically performed by computer. First, the top plate / probe was positioned 10 mm above the bottom plate. A sandwich sample with a paper-expanded sample-paper (expanded in a microwave oven as described above) configuration was then placed between the plates. The top plate was then slowly moved toward the sandwich until a force of 10 grams was felt by the force transducer. At that point, the top plate stopped and its position was recorded by the program, thereby recording the thickness of the sandwich (initial foam height). The top plate was then retracted 1 mm from the top surface of the sandwich. The program then performed five cyclic compression tests. The probe compression speed was 2 mm / s, and the compression distance was 3 mm. Because the probe started 1 mm apart, the actual compression achieved by the sandwich was 2 mm. The overall time, force, distance, and duration were recorded, and the computer program recorded the peak compression force for each cycle. The peak force for the first compression cycle was recorded as the initial force. On the fifth cycle, the foam height was measured, and the difference between the initial and final heights was calculated and reported as the foam loss. Generally, the peak force decreased with each cycle, and the sandwich thickness subsequently decreased as well. A chart was plotted to show the force (g) versus indentation (mm) for each test cycle. This is shown in Figure 2 for Sample 3.

[0048] To determine the slope, the peak force for each test cycle was plotted against the cycle number and fitted with a semi-logarithmic decay function. The slope (absolute value) was extracted for analysis and is shown in Figure 3.

[0049] Figure 4 shows a top view of a torn, expanded sample, photographed at close range with a DSLR Nikon camera equipped with a 40mm micro-Nikkor DX lens. The sample pictured in Figure 4A is made with 70% polyvinyl alcohol, 20% microspheres, 1% salt, 2% water, and 7% additives. Figure 4B shows Sample 3. Both samples contain a similar amount of void space, even with only 4% microspheres.

[0050] Figure 5 is a side view of the same sample as Figure 4. From the side, Sample 3 has only 4% microspheres, but both pictures show similar voids. Also, Figure 5B has more visible open cell structure than Figure 5A.

[0051] Foam height increases with the addition of microspheres to starch / dextrin (Comparative Sample B) and emulsion polymer (Comparative Sample C). However, when both are mixed as a binder system, foam height increases significantly (Samples 1-5). Importantly, mixing both as a binder system results in less foam loss. The use of a combined binder system results in lower tilt and improved resilience.

Claims

1. a. A binder system comprising (i) an emulsion polymer binder having a Tg range of -40°C to 60°C and (ii) a mixture of starch or dextrin; c. a plurality of pre-expanded or expandable microspheres; and d. Water-soluble salts A hybrid expandable composition comprising:

2. 10. The hybrid expandable composition of claim 1, wherein the emulsion polymer is selected from the group consisting of ethylene vinyl acetate, vinyl acetate ethylene dispersion, polyvinyl acetate, polyvinyl acetate polyvinyl alcohol, dextrin stabilized polyvinyl acetate, polyvinyl acetate copolymer, vinyl acetate-ethylene copolymer, vinyl acrylic, styrene acrylic, acrylic, styrene butyl rubber, polyurethane, and mixtures thereof.

3. 10. The hybrid expandable composition of claim 1, wherein the dextrin has a water solubility range of 25% to 75%.

4. 10. The hybrid expandable composition of claim 1, wherein the microspheres have a shell prepared from a natural, semi-synthetic, or synthetic polymer.

5. 10. The hybrid expandable composition of claim 1, wherein the microspheres have an expansion onset temperature of 80°C to 120°C.

6. 10. The hybrid intumescent composition of claim 1, wherein the water-soluble salt is selected from the group consisting of sodium chloride, potassium chloride, sodium nitrate, potassium nitrate, potassium sulfate, ammonium sulfate, and mixtures thereof.

7. a. 30 to 80 wt. % of a binder system; b. 1-15 wt. % of a plurality of microspheres; c. 0.1 to 5 wt. % of a water-soluble salt; and d. up to 5% by weight of additives selected from the group consisting of antifoaming agents, plasticizers, preservatives, surfactants, rheology modifiers, fillers, pigments, dyes, stabilizers, polyvinyl alcohol, wetting agents, and mixtures thereof 1. A hybrid foam prepared from a hybrid expandable composition comprising:

8. 10. An article comprising the hybrid intumescent composition of claim 1 and a substrate that is at least one of a cellulose substrate, wood, or a plastic film having a melting point above 100°C.

9. 9. The article of claim 8, which is a cup, food container, case, carton, bag, box, lid, package, envelope, wrap, or clamshell.

10. a. (i) 30 to 80 wt. % of a binder system which is a mixture of (1) an emulsion polymer binder having a Tg range of -40°C to 60°C and (2) starch or dextrin; (ii) 1 to 15 wt. % of a plurality of microspheres; (iv) 0.1 to 5% by weight of a water-soluble salt; and (v) up to 5% by weight of additives preparing a hybrid expandable composition comprising: b. applying the hybrid expandable composition onto a substrate in a configuration selected from the group consisting of dots, stripes, waves, checkerboard patterns, any general polyhedral shape having a substantially flat base, cylinders, and combinations thereof; c. Rapidly heating the hybrid expandable composition using microwave, infrared, radio frequency, and / or ultrasonic energy; d. A method of forming a hybrid foam comprising the step of cooling a hybrid expandable composition, whereby a hybrid foam is formed.

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