Method and apparatus for packing glass sheets with interleaf paper

Abstract

An interleaf for glass sheets includes a substrate and a coating material deposited on the substrate wherein the coating material includes a dispersing medium, a water soluble surfactant, and a water insoluble defoamer.

Description

SP24-235METHOD AND PPARATUS FOR PACKING GLASS SHEETS WITH INTERLEAF PAPERCross Reference to Related Application

[0001] This application claims the benefit of priority under 35 U.S.C. §119 of U.S. Provisional Application Serial No. 63 / 692352 filed on September 9, 2024, the content of which is relied upon and incorporated herein by reference in its entirety.Field

[0002] The present disclosure relates generally to methods and apparatuses for packing glass sheets with interleaf paper.Background

[0003] In the packing and transportation of glass sheets, such as glass sheets used for display applications, an interleaf material, such as an interleaf paper, is commonly interposed between glass sheets in order to help protect the sheets from damage. In addition to imparting physical protection, interleaf materials are also designed to minimize the transfer of contaminants onto the glass surface. Moreover, such interleaf materials should not impart undesirable levels of electrostatic charge to the glass or undesirably adhere to the glass surface. Additionally, such materials should perform well over time in a variety of different environments, such as in varying temperature and / or humidity conditions. There is a continued need for interleaf materials to meet these and other requirements in a cost effective manner.SUMMARY

[0004] Embodiments disclosed herein include an interleaf that includes a substrate including a first major surface and an opposing second major surface. The interleaf also includes a coating material deposited on at least one of the first major surface or second major surface. The coating material includes a dispersing medium, water soluble surfactant, and a water insoluble defoamer.

[0005] Embodiments disclosed herein also include an interleaf coating material. The coating material includes a dispersing medium, water soluble surfactant, and a water insoluble defoamer.SP24-235

[0006] In addition, embodiments disclosed herein include a method of packing glass sheets that includes positioning two or more glass sheets in a packing apparatus and disposing an interleaf between adjacent glass sheets of the two or more glass sheets. The interleaf includes a substrate including a first major surface and an opposing second major surface. The interleaf also includes a coating material deposited on at least one of the first major surface or second major surface. The coating material includes a dispersing medium, water soluble surfactant, and a water insoluble defoamer.

[0007] Additional features and advantages of the embodiments disclosed herein will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the disclosed embodiments as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0008] It is to be understood that both the foregoing general description and the following detailed description present embodiments intended to provide an overview or framework for understanding the nature and character of the claimed embodiments. The accompanying drawings are included to provide further understanding and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the disclosure, and together with the description serve to explain the principles and operations thereof.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a side perspective view of an exemplary packing apparatus in accordance with embodiments disclosed herein;

[0010] FIG. 2 is a side perspective view of a plurality of glass sheets and interleafs disposed between adjacent glass sheets in an exemplary packing apparatus in accordance with embodiments disclosed herein;

[0011] FIG. 3 is perspective view of an exemplary glass sheet in accordance with embodiments disclosed herein;

[0012] FIGS. 4 is a perspective view of an exemplary interleaf in accordance with embodiments disclosed herein;

[0013] FIG. 5 is an exploded cross-sectional view of a portion of an exemplary interleaf in accordance with embodiments disclosed herein;SP24-235

[0014] FIG. 6 is a schematic side view of an interleaf coating method in accordance with embodiments disclosed herein;

[0015] FIG. 7 is a chart showing water contact angle before and after washing for glass sheets sandwiched between interleafs having varying coating compositions;

[0016] FIG. 8 is a chart showing percent volume increase of varying coating compositions; and

[0017] FIGS. 9-11 are charts showing particle counts on glass sheets sandwiched between different interleafs of interest.DETAILED DESCRIPTION

[0018] Reference will now be made in detail to the present preferred embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. However, this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0019] Ranges can be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, for example by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0020] Directional terms as used herein - for example up, down, right, left, front, back, top, bottom - are made only with reference to the figures as drawn and are not intended to imply absolute orientation.

[0021] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order, nor that with any apparatus specific orientations be required. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. This holds for anySP24-235 possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps, operational flow, order of components, or orientation of components; plain meaning derived from grammatical organization or punctuation, and; the number or type of embodiments described in the specification.

[0022] As used herein, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a” component includes aspects having two or more such components, unless the context clearly indicates otherwise.

[0023] As used herein, the term “water soluble” refers to a substance that is independently dissolvable in water (e.g., at least 25 milligrams of solute per milliliter of water at 25°C).

[0024] As used herein, the term “water insoluble” refers to a substance that is independently minimally dissolvable or not dissolvable in water (e.g., less than 0. 1 milligram of solute per milliliter of water at 25 °C).

[0025] As used herein, the term “surfactant” refers to a substance that tends to reduce the surface tension of a solvent in which it is dissolved.

[0026] As used herein, the term “defoamer” refers to a substance that tends to reduce or hinder the formation of foam in solutions.

[0027] As used herein, the term “lignin” refers to a crosslinked phenolic biopolymer having a weight average molecular weight of at least about 5,000 grams per mole.

[0028] As used herein, the term “polysaccharide” refers to a polymeric carbohydrate having monosaccharide units bound by glyosidic linkages. Examples include cellulose, amylose, glucan, xylan, mannan, arabinan, and galactan.

[0029] As used herein, the term “HLB ratio” refers to the balance of the size and strength of the hydrophilic and lipophilic moieties of a surfactant molecule. The HLB scale ranges from 0 to 20, wherein a low HLB number implies a strong oil affinity and a high HLB value indicates a high water solubility (See, e.g., Kraiova and Sjoblom, Surfactants Used in Food Industry: A Review, 2009).

[0030] FIG. 1 shows a side perspective view of an exemplary packing apparatus 100 in accordance with embodiments disclosed herein. Packing apparatus 100 includes cover 102, support member 104, seat 106, pallet 108, and at least one support post 110. Packing apparatus 100 is configured to enclose a plurality of glass sheets positioned therein.

[0031] In certain exemplary embodiments, cover 102 can comprise a metal, a polymer, a polymer composite, and or metal / polymer laminate. In certain exemplary embodiments,SP24-235 support member 104, seat 106, pallet 108, and / or support post 110 can comprise a metal, such as aluminum or stainless steel, or a polymer composite.

[0032] FIG. 2 shows a side perspective view of a plurality of glass sheets 10 and interleafs 20 disposed between adjacent glass sheets 10 in an exemplary packing apparatus 100 in accordance with embodiments disclosed herein. Glass sheets 10 and interleafs 20 are positioned on cushioning member 112, which is in turn positioned over seat 106, wherein cushioning member 112 may be adhered to seat 106 with a suitable adhesive. Cushioning member 112 may, for example, comprise a resilient polymeric material, such as a material comprising ethylene-propylene-diene terpolymer.

[0033] FIG. 3 shows a perspective view of an exemplary glass sheet 10 in accordance with embodiments disclosed herein. Glass sheet 10 has a first major surface 12, an opposing second major surface 14 extending in a generally parallel direction to the first major surface 12 (on the opposite side of the glass sheet 10 as the first maj or surface 12) and an edge surface 16 extending between the first major surface 12 and the second major surface 14 and extending in a generally perpendicular direction to the first and second major surfaces 12, 14.

[0034] Glass sheet 10 may comprise a variety of glass compositions. For example, embodiments disclosed herein include those in which glass sheet 10 comprises an alkali free glass composition, comprising 58-65 weight percent (wt%) SiCh, 14-20wt% AI2O3, 8-12wt% B2O3, l-3wt% MgO, 5-10wt% CaO, and 0.5-2wt% SrO. Glass sheet 10 may also comprise an alkali free glass composition, comprising 58-65wt% SiC>2, 16-22wt% AI2O3, l-5wt% B2O3, l-4wt% MgO, 2-6wt% CaO, l-4wt% SrO, and 5-10wt% BaO. In addition, glass sheet 10 may comprise an alkali free glass composition, comprising 57-61wt% SiO2, 17-21wt% AI2O3, 5-8wt% B2O3, l-5wt% MgO, 3-9wt% CaO, 0-6wt% SrO, and 0-7wt% BaO. Glass sheet 10 may also comprise an alkali containing glass composition, comprising 55-72wt% SiO2, 12-24wt% AI2O3, 10-I8wt% Na2O, 0-10wt% B2O3, 0-5wt% K2O, 0-5wt% MgO, and 0- 5wt% CaO, which, in certain embodiments, may also comprise l-5wt% K2O and l-5wt% MgO.

[0035] In certain exemplary embodiments, glass sheet 10 has a thickness of less than about 1 millimeter, such as a thickness ranging from about 0.1 millimeters to about 1 millimeter, including from about 0.2 millimeters to about 0.8 millimeters, and further including from about 0.3 millimeters to about 0.7 millimeters, including about 0.5 millimeters.

[0036] FIG. 4 shows a perspective view of an exemplary interleaf 20 in accordance with embodiments disclosed herein. Interleaf 20 has a first major surface 22 and an opposingSP24-235 second major surface 24 extending in a generally parallel direction to the first major surface 22 (on the opposite side of the interleaf 20 as the first major surface 22).

[0037] FIG. 5 shows an exploded cross-sectional view of a portion of an exemplary interleaf 20 in accordance with embodiments disclosed herein. Interleaf 20 has a first major surface 22 and an opposing second major surface 24 extending in a generally parallel direction to the first major surface 22 (on the opposite side of the interleaf 20 as the first major surface 22). Interleaf 20 includes a substrate 30 comprising a first major surface 32 and an opposing second major surface 34 extending in a generally parallel direction to the first major surface 32. Interleaf 20 also includes a coating material 40 deposited on each of the first major surface 32 and the second major surface 34 of the substrate 30.

[0038] In certain exemplary embodiments, substrate 30 comprises paper. In certain exemplary embodiments, substrate 30 consists essentially of paper. Such embodiments include those in which the paper comprises a polysaccharide content of at least 60 weight percent and a total lignin content of at least 5 weight percent, such as a polysaccharide content of from 60 weight percent to 95 weight percent and a total lignin content of from 5 weight percent to 40 weight percent.

[0039] Embodiments disclosed herein include those in which coating material 40 includes a dispersing medium, a water soluble surfactant, and a water insoluble defoamer. Such embodiments include those in which a combined weight percent of the of the water soluble surfactant and the water insoluble defoamer in the coating material 40 ranges from 0. lwt% to 0.5wt%, such as from 0.2wt% to 0.4wt% prior to application or deposition of coating material 40 on interleaf 20. Such embodiments also include those in which a combined weight precent of the water soluble surfactant and the water insoluble defoamer in the coating material 40 deposited on interleaf 20 (e.g., subsequent to a drying step) ranges from 0.5wt% to 2.5wt%, such as from lwt% to 2wt%.

[0040] In certain exemplary embodiments, the dispersing medium comprises at least one of polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), polyacrylamide (PAAm), polyethylene glycol (PEG), hydroxypropyl methylcellulose (HPMC), Chitosan, com starch, potato starch, dextrin, poly 4 styrene sulfonate, and / or polydiallyl dimethyl ammonium chloride. In certain exemplary embodiments, the dispersing medium comprises PVA. In certain exemplary embodiments, the dispersing medium consists essentially of PVA.

[0041] In certain exemplary embodiments, the water soluble surfactant comprises at least one water soluble alcohol ethoxylate. Exemplary water soluble alcohol ethoxylates include, but are not limited to, ethoxylated 2,4,7,9-tetramethyl 5 decyn-4,7-diol (e.g., Surfynol® 465SP24-235 or Surfynol® 420 available from Evonik) and nonionic secondary alcohol ethoxylates such as Tergitol® 15-S-9 or Tergitol® 17-R-4 available from Dow Chemical.

[0042] In certain exemplary embodiments, the water insoluble defoamer comprises at least one water insoluble alcohol ethoxylate. Exemplary water insoluble alcohol ethoxylates include, but are not limited to, Tergitol® 15-S-3 available from Dow Chemical. Other exemplary water insoluble defoamers include organic based molecular defoamers, such as Surfynol® MD20 available from Evonik.

[0043] In certain exemplary embodiments, the water soluble surfactant comprises an HLB ratio of at least 10, including an HLB ratio of from 10 to 13, such as an HLB ratio of from 10.5 to 12.5, and further such as an HLB ratio of from 11 to 12.

[0044] Application of coating material 40 to substrate 30 can be accomplished by methods known to persons having ordinary skill in the art such as, for example, dip coating, wash coating, spray coating, roll coating, and / or spin coating. In addition, application of coating material 40 to substrate 30 can be accomplished as shown in FIG. 6 wherein, coating applicator 200 includes substrate (e.g., paper) dispenser 202 from which substrate 30 is discharged through first applicator 204 from which coating material 40 is deposited onto a first surface of substrate 30. Coated substrate 30 (i.e., interleaf 20) is then passed through a series of wire-wound metering rods 206 (e.g., Mayer rods), around turning rods 208, and through first drying apparatus 210 to further dry coating material 40 onto first surface of substrate 30. Interleaf 20 is subsequently flipped after which coating material 40 is deposited onto a second surface of substrate 30 via second applicator 212. Interleaf 20 is then again passed through a series of wire-wound metering rods 206, around turning rods 208, and through second drying apparatus 214 to further dry coating material 40 onto second surface of substrate 30.

[0045] Examples

[0046] Embodiments disclosed herein are further illustrated by the following non-limiting examples.

[0047] Example 1 :

[0048] Samples of Twin Rivers 3 paper from Twin Rivers Paper Company (Madawaska, Maine) were each coated with a PVA-based coating formulation comprising varying amounts of water soluble surfactants and / or water insoluble defoamers. Specifically, a first coating formulation comprised 0.4wt% Tergitol® 15-S-3, 25wt% PVA, with the balance water (“Coating Formulation 1”), a second coating formulation comprised 0.125wt% Tergitol® 15- S-9, 0. 125wt% Tergitol® 15-S-3, 25wt% PVA, with the balance water (“Coating FormulationSP24-2352”), and a third coating formulation comprised 0.25wt% Surfynol® MD20, 0.25wt% Surfynol® 465, 25wt% PVA, with the balance water (“Coating Formulation 3”). Subsequent to coating, the samples were dried for 24 hours at 25°C. Then, the samples were each stacked between sheets of Coming® Eagle XG® glass each having a thickness of 0.5 millimeters and major surface dimensions of 4 inches by 4 inches and stored at 54% relative humidity at 25°C for a period of 6 months under a weight of 3 kilograms. Subsequently, samples and glass sheets were separated followed by a washing procedure of 1 minute with Semiclean KG at 50°C with ultrasonics (104 kHz), followed by a 1 minute rinse in deionized water at 50°C, which was then followed by a spin rinse dry with nitrogen. Before and after the washing procedure, a water contact angle with the glass sheets was measured using a goniometer.

[0049] FIG. 7 shows water contact angles before and after washing for glass sheets sandwiched between interleafs having the coating compositions described above. As can be seen from FIG. 7, the combination of a water soluble surfactant and a water insoluble defoamer resulted in a lower water contact angle before and after washing than in coating compositions containing only a water insoluble defoamer. Specifically, the combination of a water soluble surfactant and a water insoluble defoamer resulted in a water contact angle of less than 10 degrees, such as a water contact angle of between 5 degrees and 10 degrees.

[0050] Example 2:

[0051] Coating Formulations 1, 2, and 3 of Example 1 were each subjected to stability testing wherein samples were visually analyzed by observing the degree of phase separation of each sample with the results shown in Table 1. As can be seen from Table 1, the combination of a water soluble surfactant and a water insoluble defoamer resulted in longer shelf stability than in coating compositions containing only a water insoluble defoamer.Table 1 : Coating Formulation Shelf Stability

[0052] Example 3:

[0053] Four different coating formulations were prepared wherein the first coating formulation comprised 0.25wt% Tergitol® 15-S-3, 25wt% PVA, with the balance water, the second coating formulation comprised 0.125wt% Tergitol® 15-S-9, 0.125wt% Tergitol® 15-SP24-235S-3, 25wt% PVA, with the balance water, a third coating formulation comprised 0.25wt% Surfynol® MD20, 25wt% PVA, with the balance water, and a fourth coating formulation comprised 0.25wt% Surfynol® MD20, 0.25wt% Surfynol® 465, 25wt% PVA, with the balance water. Each of these formulations were subjected to a foaming procedure wherein each 50 milliliters of each formulation was first weighed in a graduated cylinder to determine an initial formulation density. Next, 250 milliliters of each solution was poured into a 500 milliliter beaker and then stirred for 20 minutes with a Stir-Pak stirrer at a setting of 4 (500 rpm). After stirring, each formulation was transferred to a graduated cylinder wherein 50 milliliters of each formulation was again weighed to determine a first post stirring density, which, in turn, was used to calculate a volume percentage change due to foaming. After two hours, the same procedure was used to determine a second post stirring density and corresponding percent volume change due to foaming.

[0054] FIG. 8 shows percent volume increase of varying coating compositions subjected to the foaming procedure described above. As can be seen from FIG. 8, the combination of a water soluble surfactant and a water insoluble defoamer resulted in less percentage volume increase due to foaming than in coating compositions containing only a water insoluble defoamer.

[0055] Example 4:

[0056] Samples of 4 inch by 4 inch Coming® Eagle XG® glass were initially cleaned to have less than one observed particle per square centimeter (using a Toray laser particle counter) and a water contact angle of less than 5 degrees (as measured by a Kruss analyzer). A stack was then prepared, alternating between the interleaf of interest and glass. Specifically, the side of the paper being tested was stacked against the “A” side of the glass, and oriented vertically “upward” during stacking and vibration experiments. The stack was aged at controlled 54% relative humidity at approximately 25°C overnight prior to the experiment. The stack was then placed inside an apparatus meant to simulate commercial glass packing conditions, referred to herein as mini dense pack (MDP), which is affixed to a vibration table unit with a humidity chamber assembled around the stack apparatus and controlled to the desired level (50% relative humidity at approximately 25°C) for the duration of a two hour vibration experiment. The vibration frequencies experienced during the experiment were selected and controlled based on field testing of shipping environments experienced by large-scale glass sheets from manufacturing. After the vibration, the stack was unstacked and placed in a black carrier box. The number of particles on the surface after vibration, referred to herein as “After MDP”, were counted using the Toray laser particleSP24-235 counter. The glass was then subjected to a standard wash procedure wherein the glass was exposed to a detergent bath for 1 minute, a water bath for 1 minute, followed by a rinse-spin dry step. The number of particles on the surface after washing, referred to herein as “After MDP+wash”, were again counted using the Toray laser particle counter.

[0057] This experiment was repeated for three interleafs of interest, namely: (1) uncoated GCIP-D paper (Tokushu, Japan), which was used as a control; (2) Catalyst 57 gsm paper from Paper Excellence (Vancouver, Canada) coated with a formulation comprising 0.125wt% Tergitol® 15-S-9, 0.125wt% Tergitol® 15-S-3, 25wt% PVA, with the balance water (i.e., Coating Formulation 2 of Example 1): and (3) Catalyst 57 gsm paper coated with a formulation comprising 0.25wt% Surfynol® MD20, 0.25wt% Surfynol® 465, 25wt% PVA, with the balance water (i.e., Coating Formulation 3 of Example 1). For each interleaf of interest, particles were counted in three size ranges, small (“S”) 0.3-0.5 microns, medium (“M”) 0.5-1 microns, and large (“L”) greater than 1 micron.

[0058] FIGS. 9-11 show particle counts on glass sheets sandwiched between the different interleafs of interest described above. As can be seen from FIGS. 9-11, the presence of a coating composition comprising a combination of a water soluble surfactant and a water insoluble defoamer resulted in lower particle counts after washing as compared to uncoated paper. Specifically, the coating compositions comprising a combination of a water soluble surfactant and a water insoluble defoamer resulted in less than 10 particles per square centimeter, such as from 5 particles to 10 particles per square centimeter on glass sheets sandwiched between interleafs coated with these compositions.

[0059] Embodiments disclosed herein, wherein an interleaf coating material includes a combination of a water soluble surfactant and a water insoluble defoamer, can enable improved dispersion of the defoamer in the coating material due at least in part to the presence of the water soluble surfactant. This combination can also further enable the function of the defoamer as a bubble suppressant while at the same time increase the wettability and hence stability of the defoamer in the coating material. Specifically, it can enable the defoamer to bloom on the surface of the coating material while maintaining sufficient dispersion of the defoamer such that the defoamer does not phase separate from the bulk of the coating material. This can, in turn, improve shelf stability of the coating over extended time periods. Embodiments disclosed herein can additionally enable highly washable glass surfaces with relatively low particle density subsequent to the glass being packed and transported between interleafs coated with coating materials as disclosed herein.SP24-235

[0060] It will be apparent to those skilled in the art that various modifications and variations can be made to embodiments of the present disclosure without departing from the spirit and scope of the disclosure. Thus, it is intended that the present disclosure cover such modifications and variations provided they come within the scope of the appended claims and their equivalents.

Claims

SP24-235What is claimed is:

1. An interleaf comprising: a substrate comprising a first major surface and an opposing second major surface; and a coating material deposited on at least one of the first major surface or second major surface, the coating material comprising: a dispersing medium; a water soluble surfactant; and a water insoluble defoamer.

2. The interleaf of claim 1, wherein the substrate comprises paper.

3. The interleaf of claim 2, wherein the paper comprises a polysaccharide content of at least 60 weight percent and a total lignin content of at least 5 weight percent.

4. The interleaf of claim 1, wherein a combined weight percent of the of the water soluble surfactant and the water insoluble defoamer in the coating material ranges from 0.5wt% to 2.5wt%.

5. The interleaf of claim 4, wherein the water soluble surfactant comprises at least one water soluble alcohol ethoxylate.

6. The interleaf of claim 4, wherein the water insoluble defoamer comprises at least one water insoluble alcohol ethoxylate.

7. The interleaf of claim 1, wherein the dispersing medium comprises at least one of polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), polyacrylamide (PAAm), polyethylene glycol (PEG), hydroxypropyl methylcellulose (HPMC), Chitosan, com starch, potato starch, dextrin, poly 4 styrene sulfonate, or polydiallyl dimethyl ammonium chloride.SP24-2358. The interleaf of claim 1, wherein the water soluble surfactant comprises anHLB ratio of at least 10.

9. An interleaf coating material comprising: a dispersing medium; a water soluble surfactant; and a water insoluble defoamer.

10. The interleaf coating material of claim 9, wherein a combined weight percent of the of the water soluble surfactant and the water insoluble defoamer in the coating material ranges from 0.5wt% to 2.5wt%.

11. The interleaf coating material of claim 10, wherein the water soluble surfactant comprises at least one at least one water soluble alcohol ethoxylate.

12. The interleaf coating material of claim 10, wherein the water insoluble defoamer comprises at least one water insoluble alcohol ethoxylate.

13. The interleaf coating material of claim 9, wherein the dispersing medium comprises at least one of polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), polyacrylamide (PAAm), polyethylene glycol (PEG), hydroxypropyl methylcellulose (HPMC), Chitosan, com starch, potato starch, dextrin, poly 4 styrene sulfonate, or polydiallyl dimethyl ammonium chloride.

14. The interleaf coating material of claim 9, wherein the water soluble surfactant comprises an HLB ratio of at least 10.

15. A method of packing glass sheets comprising: positioning two or more glass sheets in a packing apparatus; and disposing an interleaf between adjacent glass sheets of the two or more glass sheets, the interleaf comprising:SP24-235 a substrate comprising a first major surface and an opposing second major surface; and a coating material deposited on at least one of the first major surface or second major surface, the coating material comprising: a dispersing medium; a water soluble surfactant; and a water insoluble defoamer.

16. The method of claim 15, wherein the substrate comprises paper.

17. The method of claim 15, wherein a combined weight percent of the of the water soluble surfactant and the water insoluble defoamer in the coating material ranges from 0.5wt% to 2.5wt%.

18. The method of claim 17, wherein the water soluble surfactant comprises at least one water soluble alcohol ethoxylate.

19. The method of claim 17, wherein the water insoluble defoamer comprises at least one water insoluble alcohol ethoxylate.

20. The method of claim 15, wherein the water soluble surfactant comprises anHLB ratio of at least 10.

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