阅读说明：本技术 用于纸板的可热密封的屏障涂层 (Heat sealable barrier coating for paperboard ) 是由 L·J·福丁 K·L·维斯 于 2018-09-05 设计创作，主要内容包括：本发明提供了一种纸板坯料和由其制成的杯。该坯料包括具有第一侧面和第二侧面的纸板基底。第一聚合物层可设置在纸板基底的第一侧面的至少一部分上,并且第二聚合物层可设置在纸板基底的第二侧面的至少一部分上。第一聚合物层和第二聚合物层均可包含至少一种为热塑性的聚合物组分。第二聚合物层还包含至少一种聚合物组分,其不存在于第一聚合物层中,并且具有高于第一聚合物层的所有聚合物组分的玻璃化转变温度。(The invention provides a paperboard blank and a cup made therefrom. The blank includes a paperboard substrate having a first side and a second side. The first polymer layer may be disposed on at least a portion of the first side of the paperboard substrate and the second polymer layer may be disposed on at least a portion of the second side of the paperboard substrate. Both the first polymer layer and the second polymer layer may comprise at least one polymer component that is thermoplastic. The second polymer layer also includes at least one polymer component that is not present in the first polymer layer and has a glass transition temperature that is higher than all of the polymer components of the first polymer layer.)

1. A paperboard blank, comprising:

a paperboard substrate having a first side and a second side;

a first polymer layer disposed on at least a portion of the first side of the paperboard substrate; and

a second polymer layer disposed on at least a portion of the second side of the paperboard substrate, wherein the first polymer layer and the second polymer layer each comprise at least one polymer component that is thermoplastic, and the second polymer layer further comprises a polymer component that is not present in the first polymer layer, the polymer component having a higher glass transition temperature than the polymer component of the first polymer layer.

2. The paperboard blank of claim 1, wherein the first polymer layer and the second polymer layer both comprise styrene acrylic.

3. The paperboard blank of claim 1, wherein the polymer component of the second polymer layer that is not present in the first polymer layer and has a higher glass transition temperature than the polymer component of the first polymer layer is a polyester.

4. The paperboard blank of claim 1, wherein at least one of the first side and the second side of the paperboard substrate is at least partially coated with clay.

5. The paperboard blank of claim 1, wherein the polymer component in the second polymer layer that is not present in the first polymer layer has a glass transition temperature that is at least 5 ° f higher than the glass transition temperature of any polymer component in the first polymer layer.

6. The paperboard blank of claim 1, wherein the first polymer layer or the second polymer layer comprises a vinylidene chloride terpolymer.

7. The paperboard blank of claim 1, wherein the first polymer layer or the second polymer layer comprises polyvinylidene chloride.

8. A paperboard blank, comprising:

a paperboard substrate having a first side and a second side;

a first polymer layer disposed on at least a portion of the first side of the paperboard substrate; and

a second polymer layer disposed on at least a portion of the second side of the paperboard substrate, wherein the first polymer layer and the second polymer layer each comprise at least one polymer component that is styrene acrylic, and the second polymer layer further comprises a polymer component having a glass transition temperature that is at least 15 ° F higher than the polymer component of the first polymer layer.

9. The paperboard blank of claim 8, wherein the polymer component in the second polymer layer having a glass transition temperature at least 15 ° f higher than the polymer component of the first polymer layer is a polyester.

10. The paperboard blank of claim 8, wherein at least one of the first side and the second side of the paperboard substrate is at least partially coated with calcium carbonate.

11. The paperboard blank of claim 8, wherein the first polymer layer or the second polymer layer comprises a vinylidene chloride terpolymer.

12. The paperboard blank of claim 8, wherein the first polymer layer or the second polymer layer comprises polyvinylidene chloride.

13. A cup, comprising:

a sidewall having a first side and a second side, wherein a first polymer layer is disposed on at least a portion of the first side of the sidewall and a second polymer layer is disposed on at least a portion of the second side of the sidewall,

wherein the first polymer layer and the second polymer layer each comprise at least one polymer component that is thermoplastic, and the second polymer layer further comprises a polymer component that is not present in the first polymer layer, the polymer component having a higher glass transition temperature than the polymer component of the first polymer layer.

14. The cup of claim 13, wherein the first polymer layer and the second polymer layer both comprise styrene acrylic.

15. The cup of claim 13, wherein the polymer component of the second polymer layer that is not present in the first polymer layer and has a higher glass transition temperature than the polymer component of the first polymer layer is a polyester.

16. The cup of claim 13, wherein at least one of the first side and the second side of the sidewall is at least partially coated with calcium carbonate.

17. The cup of claim 13, wherein the polymer component in the second polymer layer that is not present in the first polymer layer has a glass transition temperature that is at least 15 ° f higher than the glass transition temperature of any polymer component in the first polymer layer.

18. The cup of claim 13, wherein the first polymer layer or the second polymer layer comprises a vinylidene chloride terpolymer.

19. The cup of claim 13, further comprising a bottom panel secured proximate a lower edge of the sidewall, wherein the second polymer layer is disposed on at least a portion of the bottom panel that is in contact with the lower edge of the first surface of the sidewall.

20. A cup, comprising:

a sidewall having a first side and a second side; and

a bottom panel secured proximate a lower edge of the side walls, wherein a first polymer layer is disposed on the first side of the side walls and a second polymer layer is disposed on at least a portion of an edge of the bottom panel contacting the side walls, the side walls having the first polymer layer disposed thereon, and

wherein the first polymer layer and the second polymer layer each comprise at least one polymer component that is thermoplastic, and the second polymer layer further comprises a polymer component that is not present in the first polymer layer, the polymer component having a higher glass transition temperature than the polymer component of the first polymer layer.

21. The cup of claim 20, wherein the first polymer layer and the second polymer layer both comprise styrene acrylic.

22. The cup of claim 20, wherein the polymer component of the second polymer layer that is not present in the first polymer layer and has a higher glass transition temperature than the polymer component of the first polymer layer is a polyester.

23. The cup of claim 20 wherein at least one of the first side and the second side of the sidewall is at least partially coated with calcium carbonate.

24. The cup of claim 20, wherein the polymer component in the second polymer layer that is not present in the first polymer layer has a glass transition temperature that is at least 15 ° f higher than the glass transition temperature of any polymer component in the first polymer layer.

25. The cup of claim 20, wherein the first polymer layer or the second polymer layer comprises a vinylidene chloride terpolymer.

Technical Field

Embodiments described herein relate generally to paperboard blanks for paper products, methods of making the same, and paperboard products made therefrom. More particularly, the embodiments described relate generally to cup stock.

Background

Disclosure of Invention

The invention provides a paperboard blank, a cup made from the blank and a method of making the same. The blank includes a paperboard substrate having a first side and a second side. The first polymer layer may be disposed on at least a portion of the first side of the paperboard substrate and the second polymer layer may be disposed on at least a portion of the second side of the paperboard substrate. Both the first polymer layer and the second polymer layer may comprise at least one polymer component that is thermoplastic. The second polymer layer also includes at least one polymer component that is not present in the first polymer layer and has a glass transition temperature that is higher than all of the polymer components of the first polymer layer. The blank may be used to make a cup or other beverage container.

The cup can include a sidewall having a first side and a second side, wherein a first polymer layer is disposed on at least a portion of the first side of the sidewall and a second polymer layer is disposed on at least a portion of the second side of the sidewall. Both the first polymer layer and the second polymer layer may comprise at least one polymer component that is thermoplastic. The second polymer layer further comprises a polymer component that is not present in the first polymer layer, and the polymer component has a higher glass transition temperature than the polymer component of the first polymer layer.

Drawings

Fig. 1 shows a schematic view of an exemplary blank according to one or more described embodiments.

Fig. 2 shows a schematic cross-sectional view of the blank shown in fig. 1, shown along line 2-2, according to one or more described embodiments.

Fig. 3 shows a partially cut-away perspective view of an exemplary paper cup according to one or more described embodiments.

Detailed Description

It has surprisingly been found that coated paperboard has different polymer layers, wherein one side of the paperboard has at least one polymer component which is not present in the other side and which has a higher glass transition temperature (Tg) than the polymer component of the other side. This difference in Tg provides superior heat sealing compared to paperboard coated on both sides with polymer compositions having similar Tg. More surprisingly, it was found that when treating a thermoplastic material on a surface of a paperboard, the opposite surface shows a significantly more efficient heat sealing behaviour when blended with a second thermoplastic material not present in the opposite surface, and more specifically a second thermoplastic material having a higher glass transition temperature (Tg) than the thermoplastic material of the other side.

As used herein, the term "glass transition temperature" refers to the temperature (Tg) measured according to ASTM D3418 at which a thermoplastic transitions from a hard and relatively brittle "glassy" state to a viscous or rubbery state. The glass transition temperature (Tg) is lower than the melting temperature (Tm) of the crystalline state of the thermoplastic material.

By "thermoplastic polymer" is meant a polymer that can be melted by heating and then cooled without significantly changing properties. Thermoplastic polymers generally include, but are not limited to, styrene, acrylates, methacrylates, vinyls, polyhaloolefins, polyolefins, polyamides, polyesters, polycarbonates, polysulfones, polyacetals, polylactones, acrylonitrile butadiene styrene resins, polyphenylene oxides, polyphenylene sulfides, styrene-acrylic, styrene-butadiene, styrene-acrylonitrile resins, styrene maleic anhydride, polyimides, aromatic polyketones, or copolymers or mixtures of any two or more of the foregoing. The preferred polyhaloolefin is polyvinylidene chloride.

Suitable thermoplastic polymers may be or include acrylic acid or derivatives and salts thereof. For example, suitable polymers may include any one or more of the following: polyacrylic acids and polyacrylic acids, such as poly (benzyl acrylate), poly (butyl acrylate), poly (2-cyanobutyl acrylate), poly (2-ethoxyethyl acrylate), poly (ethyl acrylate), poly (2-ethylhexyl acrylate), poly (fluoromethyl acrylate), poly (5,5,6,6,7,7, 7-heptafluoro-3-oxyheptyl acrylate), poly (heptafluoro-2-propyl acrylate), poly (heptyl acrylate), poly (hexyl acrylate), poly (isobornyl acrylate), poly (isopropyl acrylate), poly (3-methoxybutyl acrylate), poly (methyl acrylate), poly (nonyl acrylate), poly (octyl acrylate), poly (propyl acrylate), poly (p-tolyl acrylate), poly (acrylic acid) and their derivatives and salts; polyacrylamides such as poly (acrylamide), poly (N-butylacrylamide), poly (N, N-dibutylacrylamide), poly (N-dodecylacrylamide), and poly (morpholinylacrylamide); polymethacrylic acids and poly (methacrylates) such as poly (benzyl methacrylate), poly (octyl methacrylate), poly (butyl methacrylate), poly (2-chloroethyl methacrylate), poly (2-cyanoethyl methacrylate), poly (dodecyl methacrylate), poly (2-ethylhexyl methacrylate), poly (ethyl methacrylate), poly (1,1, 1-trifluoro-2-propyl methacrylate), poly (hexyl methacrylate), poly (2-hydroxyethyl methacrylate), poly (2-hydroxypropyl methacrylate), poly (isopropyl methacrylate), poly (methacrylic acid), poly (methyl methacrylate) in various forms such as atactic, isotactic, syndiotactic and heteric; and poly (propyl methacrylate); polymethacrylamides such as poly (4-carboxyphenylmethacrylamide); other alpha-and beta-substituted poly (acrylic acids) and poly (methacrylic acids) such as poly (chlorobutyl acrylate), poly (ethylethoxycarbonyl methacrylate), poly (methyl fluoroacrylate) and poly (methylphenyl acrylate).

Exemplary thermoplastic polymers may also comprise one or more polyolefins, including polyolefin homopolymers and polyolefin copolymers. Exemplary polyolefins may be prepared from monoolefin monomers including, but not limited to, monomers having 2 to 7 carbon atoms such as ethylene, propylene, 1-butene, isobutylene, 1-pentene, 1-hexene, 1-octene, 3-methyl-1-pentene, 4-methyl-1-pentene, 5-methyl-l-hexene, mixtures thereof and copolymers thereof with (meth) acrylates and/or vinyl acetate. Exemplary polyolefins may also include: polymers comprising one or more linear, branched or cyclic C2 to C40 olefins, preferably polymers comprising propylene copolymerized with one or more C3 to C40 olefins, preferably C3 to C20 alpha olefins, more preferably C3 to CIO alpha olefins. The polyolefin may further comprise: polymers comprising ethylene, including but not limited to ethylene copolymerized with C3 to C40 olefins, preferably C3 to C20 alpha olefins, more preferably propylene and/or butene. Unless otherwise indicated, the term "copolymer" refers to a polymer derived from two or more monomers (including terpolymers, tetrapolymers, etc.), and the term "polymer" refers to any carbon-containing compound having repeating units from one or more different monomers.

Certain examples are shown in the provided figures and described in detail below. In describing these examples, similar or identical reference numbers are used to identify common or similar elements. The figures are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated or schematic in the interest of clarity and/or conciseness.

Fig. 1 shows a schematic view of an exemplary blank 100 according to one or more embodiments, and fig. 2 shows a schematic cross-sectional view along line 2-2 of the blank 100 shown in fig. 1. The coated paperboard 100 may include a first polymer layer 110 disposed on at least a portion of the first side 125 of the paperboard substrate 130, and a second polymer layer 150 disposed on at least a portion of the second side 135 of the paperboard substrate 130. In another embodiment, the coated paperboard 100 may include the first polymer layer 110 disposed on at least a portion of the first side 125 of the paperboard substrate 130, and the second side 135 of the paperboard substrate 130 may be exposed. Each polymer layer 110, 150 may be one or more individual layers or films, each layer or film having a thickness in a range of from as low as about 0.002mm, about 0.005mm, about 0.01mm, about 0.03mm, about 0.05mm, about 0.07mm, or from about 0.1mm to as high as about 0.15mm, about 0.17mm, about 0.2mm, about 0.25mm, about 0.3mm, or about 0.35 mm.

The one or more first polymer layers 110 and second polymer layers 150 can be disposed on either side of the paperboard substrate 130 using any suitable method, including dip coating, rod coating, knife coating, gravure and reverse roll coating, slide coating, bead coating, extrusion coating, curtain coating, and the like. Other suitable coating methods include, but are not limited to, wound wire rod coating, slot coating, slide hopper coating, gravure printing, curtain coating, and the like. Some of these methods allow two or more layers to be applied simultaneously, which is preferred from a manufacturing economy standpoint. Additional coating techniques and drying methods are described in more detail in U.S. patent No. 6,884,479. After coating, the layer can be dried by simple evaporation, which can be accelerated using known techniques such as, for example, convection heating.

Each polymer layer 110, 150 can include any number of polymer components. Each polymer layer 110, 150 may include one or more thermoplastic polymer components to provide the paperboard 100 with sufficient liquid-resistant properties. The first polymer layer 110 and the second polymer layer 150 can be the same except that the second polymer layer 150 is a blend of two or more polymer components having different glass transition temperatures — one glass transition temperature for each component. The blend in the second polymer layer 150 comprises at least one polymer component that is not present in the first polymer layer 110 and has a higher glass transition temperature than the polymer component of the first polymer layer 110. In other words, the second polymer layer 150 may have at least one polymer component that is not present in the first polymer layer 130 and that has a glass transition temperature that is higher than all of the glass transition temperatures of each of the polymer components of the first polymer layer 110.

In certain embodiments, each polymer component in the polymer layers 110, 150 may have a glass transition temperature ranging from as low as about-20 ° f, about 0 ° f, or from about 50 ° f to as high as about 80 ° f, 120 ° f, or 160 ° f. Each component in the polymer layers 110, 150 may also have a glass transition temperature in the following range: about-20F to about 200F; about-20 ° F to about 50 ° F; about-20F to about 38F; about-10 ° F to about 80 ° F; about 0F to about 150F; or from about 50F to about 280F. In certain embodiments, the glass transition temperature of each polymer component in both polymer layers 110, 150 is less than room temperature (e.g., less than 78 ° f/25 ℃). In certain embodiments, the glass transition temperature of the polymer component in the first polymer layer 110 is less than room temperature (e.g., less than 78 ° f/25 ℃). In certain embodiments, the glass transition temperature of the polymer component in the first polymer layer 110 is approximately or above room temperature (e.g., less than 78 ° f/25 ℃). In certain embodiments, the glass transition temperature of each polymer component in the second polymer layer 150 may be less than 32 ° f, about 66 ° f, or about 86 ° f. In certain embodiments, the glass transition temperature of each polymer component in the first polymer layer 110 may be less than 32 ° f, about 60 ° f, about 90 ° f, or about 140 ° f.

The difference between the highest glass transition temperature component in the first polymer layer 110 and the highest glass transition temperature component in the second polymer layer 150 (highest polymer component Tg of the second layer 150 minus the highest polymer component Tg of the first layer 110) can be at least 10 ° f, 15 ° f, or 20 ° f or greater. This difference may also be referred to as a "Tg difference". The Tg difference may be about 5F, about 10F, about 15F, about 18F, about 25F, or about 27F. The Tg difference may also be in the range of as low as about 5F, 10F, 15F or 20F to as high as about 40F, 70F or 100F. The Tg difference can also be from 5F to 30F, from 10F to 150F; 15 ° f to 125 ° f; 10 to 70 ° F; or from 32F to 83F.

Surface treatment for substrates

Prior to application of the polymer layers 110, 150, one or both of the outer surfaces of the paperboard may be surface treated to increase the surface energy to make the paperboard surface more amenable to metallization, coating, printing inks, and/or lamination. The surface treatment may be carried out according to one of the methods known in the art, including corona discharge, flame, plasma, chemical treatment or treatment by means of a polarized flame.

The surface to be coated may be further treated to increase its surface energy prior to applying the top coat to the outer surface. For example, the surface to be coated may be treated using flame treatment, plasma, corona discharge, chlorination of the film (e.g., exposing the film surface to gaseous chlorine), treatment with an oxidizing agent such as chromic acid, hot air or steam treatment, flame treatment, and the like. While any of these techniques can be effectively employed to pretreat the surface, a preferred method may be corona discharge, with such electron treatment methods involving exposing the surface to a high voltage corona discharge while passing the film between a pair of spaced electrodes. After treating the surface, the polymer layer 110, 150 may then be applied thereto.

In one or more embodiments, the primer coating may be applied as a top coat to one or more surfaces of the substrate. The primer may be applied to the surface prior to applying the polymeric layer 110, 150 or prior to applying another top coat. When a primer is to be applied, the underlying surface may be treated by one of the methods previously described.

Suitable primer materials are well known in the art and include, for example, epoxy and Polyethyleneimine) (PEI) materials. U.S. Pat. No. 3,753,769, U.S. Pat. No. 4,058,645 and U.S. Pat. No. 4,439,493, respectively, are incorporated herein by reference, disclosing the use and application of such primers. The primer provides an overall adhesive active surface for a thorough and secure bond with a subsequently applied polymer layer, and may be applied to the substrate by conventional solution coating methods (e.g., by roll application).

The preferred surface treatment under the heat sealable barrier layer is size press coating (mostly starch, but also polyvinyl alcohol, polymer latex polymers and clays or other minerals present). While size press coating can help prevent penetration of the heat seal layer, subsequent coatings can also be applied to further smooth the surface (so that there are no pinholes in the barrier from pre-existing "high spots") and also provide smaller pore sizes on the surface to help ensure that the dispersed polymer remains on the surface rather than being dragged in with the water dispersed therein. The resistant layer is likely a conventional paper coating comprising primarily inorganic particles (calcium carbonate or clay) and a small amount of a polymeric binder to hold the particles together.

Paperboard substrate

Paperboard substrate 130 can be or include any paperboard material capable of forming a desired paper container. Paperboard materials suitable for use as the paperboard substrate 130 may have a basis weight of from about 60 pounds to about 250 pounds per 3,000 square feet of paperboard substrate or from about 120 pounds to about 250 pounds per 3,000 square feet of paperboard substrate. The basis weight of the paperboard material can range from as low as about 60lbs, 75lbs, or 120lbs to as high as about 200lbs, 230lbs, or 250lbs per square foot of paperboard substrate. The paperboard material may have a thickness of as low as about 125 μm, about 175 μm, about 200 μm, about 225 μm, or about 250 μm to as high as about 350 μm, about 400 μm, about 450 μm, about 500 μm, about 550 μm, or about 600 μm. As another example, the paperboard material can have a thickness of from about 185 μm to about 475 μm, from about 215 μm to about 425 μm, or from about 235 μm to about 375 μm.

As described above, the paperboard substrate 130 may be uncoated or coated prior to the addition of the first polymer layer 110 and the second polymer layer 150. For example, one or both sides of substrate 130 may be coated with one or more layers, including size press, wax, and or clay. Each coating may have a thickness in a range of from as low as about 0.002mm, about 0.005mm, about 0.01mm, about 0.03mm, about 0.05mm, about 0.07mm, or about 0.1mm to as high as about 0.15mm, about 0.17mm, about 0.2mm, about 0.25mm, about 0.3mm, or about 0.35 mm.

Commercially available paperboard materials that may be used as the paperboard substrate 130 may include, but are not limited to, Solid Bleached Sulfate (SBS) cupstock, bleached virgin board, unbleached virgin board, recycled bleached board, recycled unbleached board, or any combination thereof. For example, SBS cup stock available from Georgia-Pacific Corporation (Georgia-Pacific Corporation) may be used as the second layer 150.

Cup with elastic band

The coated paperboard 100 may be a blank that is formed into a paper product, such as a bowl, tray, container, tray, platter, deep dish container, fluted product, or cup. The terms "paper product," "paper container," "paperboard product," and "paperboard container" are intended to be interchangeable herein. For simplicity and ease of description, the embodiments provided herein will be further described with reference to a paper cup as shown in fig. 3.

Fig. 3 illustrates a partially cut-away perspective view of an exemplary paper cup 300 in accordance with one or more embodiments. The paper cup 300 may include a side wall 305, a bottom panel or cup bottom 320, and a brim roll 315. Referring to fig. 1-3, the blank 100 may have a first or "top" edge 107, a second or "bottom" edge 109, a third or "left" edge 111, and a fourth or "right" edge 113. The first edge 107 and the second edge 109 are opposite to each other, and the third edge 111 and the fourth edge 113 are opposite to each other. The blank 100 may be formed into a paper cup 300 having a frustoconical outer side wall 305. The third edge 111 and the fourth edge 113 may overlap each other to form a sidewall 305 having a seam 310, the first edge 107 may be crimped to form a brim 315, and a bottom panel 320 may be secured to the sidewall 305 at or adjacent to the second edge 109.

The side wall 305 may be formed by rolling or otherwise placing the third and fourth edges 111, 113 of the coated paperboard 100 shown in fig. 1 in contact with each other to form a seam 310. For example, the coated paperboard 100 may be formed around a mandrel to form the seam 310. Thus, the first edge 107 may form a first or "top" edge of the sidewall 305 and the second edge 109 may form a second or "bottom" edge of the sidewall 305. The sidewall 305 may be heat sealed to provide a sealed seam 310.

The floor 320 may be disposed on the sidewall 305 or otherwise secured to the sidewall 305, such as near or adjacent to a second edge of the sidewall, such that the sidewall 305 and the floor 320 define a container volume 530. The bottom panel 320 may be coupled, secured, joined, fastened, attached, connected, or otherwise secured to the side wall 305 by an adhesive and/or any other method known in the art, including heat sealing. The bottom sheet 320 may be coated in a polymeric material capable of forming a seal between the first polymeric layers 110 of the coated paperboard 100. For example, the base plate 320 may be coated with the second polymer layer 150.

The outer and/or inner surfaces of the side walls 305 may include one or more printed patterns that may be applied to the coated paperboard 100. "printed pattern" and similar terms may refer to an ink printed pattern for aesthetic purposes. However, such features may have functional aspects such as indicating fill lines.

The paper cup 300 may have any suitable container volume 530. For example, the container volume 330 may range from as low as about 20mL, about 40mL, about 60mL, about 80mL, or about 100mL to as high as about 120mL, about 200mL, about 300mL, about 400mL, about 500mL, about 750mL, about 1,000mL, about 1,300mL, or about 1,500 mL. For example, the container volume 595 may be about 150mL to about 500mL, about 450mL to about 1,000mL, about 400mL to about 900mL, or about 800mL to about 1,300 mL.

Any one or more of the layers 110, 130, 150 of the paperboard 100 may include one or more additives to improve processability or handling. Suitable additives may include, but are not limited to, opacifiers, pigments, colorants, fillers, spacers, crosslinkers, surfactants, defoamers, rheology modifiers, slip agents, antioxidants, antistatic agents, moisture barrier additives, gas barrier additives, and combinations thereof. Examples of suitable opacifiers, pigments or colorants are iron oxide, carbon black, aluminum, titanium dioxide (TiO)₂) Calcium carbonate (CaCO)₃) Polybutylene terephthalate (PBT), talc, β nucleating agents, and combinations thereof.

The slip agent may include higher fatty acid amides, higher fatty acid esters, waxes, silicone oils and metal soaps. Such slip agents may be used in amounts ranging from 0.1 to 2 weight percent, based on the total weight of the layer to which they may be added.

Suitable antioxidants may include phenolic antioxidants. Antioxidants can generally be used in amounts ranging from 0.1 to 2 weight percent, based on the total weight of the layer to which they can be added.

Antistatic agents may include alkali metal sulfonates, polyether-modified polydiorganosiloxanes, polyalkylphenylsiloxanes and tertiary amines. Such antistatic agents may be used in an amount ranging from about 0.05 to 3 weight percent, based on the total weight of the layer.

Fillers useful in the present invention may include finely divided inorganic solid materials such as silica, fumed silica, diatomaceous earth, calcium carbonate, calcium silicate, aluminum silicate, kaolin, talc, bentonite, clay and pulp.

Suitable moisture and gas barrier additives may include effective amounts of low molecular weight resins, hydrocarbon resins, especially petroleum resins, styrene resins, cyclopentadiene resins, and terpene resins.

Such additives may be used in effective amounts, which vary depending on the desired characteristics. To prevent clogging, for example, one or both of the layers 110, 150 may include one or more anti-block particles or slip additives. Metal, such as aluminum, may be disposed on one or both sides of the paperboard 100 to provide good barrier properties, which may be desirable for certain food packaging applications. The total amount of additives may include up to about 20 wt% of the layer, but some embodiments may include additives in an amount up to about 30 wt% of the layer.